A statistical spectropolarimetric study of Herbig Ae/Be stars

NASA Astrophysics Data System (ADS)

Ababakr, K. M.; Oudmaijer, R. D.; Vink, J. S.

2017-11-01

We present H α linear spectropolarimetry of a large sample of Herbig Ae/Be stars. Together with newly obtained data for 17 objects, the sample contains 56 objects, the largest such sample to date. A change in linear polarization across the H α line is detected in 42 (75 per cent) objects, which confirms the previous finding that the circumstellar environment around these stars on small spatial scales has an asymmetric structure, which is typically identified with a disc. A second outcome of this research is that we confirm that Herbig Ae stars are similar to T Tauri stars in displaying a line polarization effect, while depolarization is more common among Herbig Be stars. This finding had been suggested previously to indicate that Herbig Ae stars form in the same manner than T Tauri stars through magnetospheric accretion. It appears that the transition between these two differing polarization line effects occurs around the B7-B8 spectral type. This would in turn not only suggest that Herbig Ae stars accrete in a similar fashion as lower mass stars, but also that this accretion mechanism switches to a different type of accretion for Herbig Be stars. We report that the magnitude of the line effect caused by electron scattering close to the stars does not exceed 2 per cent. Only a very weak correlation is found between the magnitude of the line effect and the spectral type or the strength of the H α line. This indicates that the detection of a line effect only relies on the geometry of the line-forming region and the geometry of the scattering electrons.

Observations of the peculiar object MWC 560 in outburst

NASA Technical Reports Server (NTRS)

Michalitsianos, A. G.; Maran, S. P.; Oliversen, R. J.; Bopp, B.; Kontizas, E.

1991-01-01

The results of ultraviolet spectroscopy, photoelectric photometry, and supplemental high-resolution H(alpha) spectroscopy of a photometric outburst of MWC 560 are discussed. Ultraviolet spectra are shown to be consistent with the ejection of an optically thick shell that produced strong absorption blends of Fe II and Cr II. The velocities reported exceed by far those previously found in symbiotic stars or recurrent novas. In addition to the variable high-velocity system of broad absorption features, a relatively stable system of Mg II, Mg I, Fe II, Cr II, and other ionic absorptions is observed. It is pointed out that the spectroscopic phenomena in MWC 560 resemble those found in XX Ophiuchi, but the velocities in the MWC 560 are an order of magnitude higher than those found in XX Oph.

The Asymmetrical Wind of the Candidate Luminous Blue Variable MWC 314

NASA Technical Reports Server (NTRS)

Wisniewski, John P.; Babler, Brian L.; Bjorkman, Karen S.; Kurchakov, Anatoly V.; Meade,Marilyn R.; Miroshnichenko, Anatoly S.

2006-01-01

We present the results of long-term spectropolarimetric and spectroscopic monitoring of MWC 314, a candidate Luminous Blue Variable star. We detect the first evidence of H alpha variability in MWC 314, and find no apparent periodicity in this emission. The total R-band polarization is observed to vary between 2.21% and 3.00% at a position angle consistently around approximately 0 degrees, indicating the presence of a time-variable intrinsic polarization component, hence an asymmetrical circumstellar envelope. We find suggestive evidence that MWC 314's intrinsic polarization exhibits a wavelength-independent magnitude varying between 0.09% and 0.58% at a wavelength-independent position angle covering all four quadrants of the Stokes Q-U plane. Electron scattering off of density clumps in MWC 314's wind is considered as the probable mechanism responsible for these variations.

The excess infrared emission of Herbig Ae/Be stars - Disks or envelopes?

NASA Technical Reports Server (NTRS)

Hartmann, Lee; Kenyon, Scott J.; Calvet, Nuria

1993-01-01

It is suggested that the near-IR emission in many Herbig Ae/Be stars arises in surrounding dusty envelopes, rather than circumstellar disks. It is shown that disks around Ae/Be stars are likely to remain optically thick at the required accretion rates. It is proposed that the IR excesses of many Ae/Be stars originate in surrounding dust nebulae instead of circumstellar disks. It is suggested that the near-IR emission of the envelope is enhanced by the same processes that produce anomalous strong continuum emission at temperatures of about 1000 K in reflection nebulae surrounding hot stars. This near-IR emission could be due to small grains transiently heated by UV photons. The dust envelopes could be associated with the primary star or a nearby companion star. Some Ae/Be stars show evidence for the 3.3-6.3-micron emission features seen in reflection nebulae around hot stars, which lends further support to this suggestion.

Broad absorption line symbiotic stars: highly ionized species in the fast outflow from MWC 560

NASA Astrophysics Data System (ADS)

Lucy, Adrian B.; Knigge, Christian; Sokoloski, J. L.

2018-07-01

In symbiotic binaries, jets and disc winds may be integral to the physics of accretion on to white dwarfs from cool giants. The persistent outflow from symbiotic star MWC 560 (≡V694 Mon) is known to manifest as broad absorption lines (BALs), most prominently at the Balmer transitions. We report the detection of high-ionization BALs from C IV, Si IV, N V, and He II in International Ultraviolet Explorer spectra obtained on 1990 April 29-30, when an optical outburst temporarily erased the obscuring `iron curtain' of absorption troughs from Fe II and similar ions. The C IV and Si IV BALs reached maximum radial velocities at least 1000 km s-1 higher than contemporaneous Mg II and He II BALs; the same behaviours occur in the winds of quasars and cataclysmic variables. An iron curtain lifts to unveil high-ionization BALs during the P Cygni phase observed in some novae, suggesting by analogy a temporary switch in MWC 560 from persistent outflow to discrete mass ejection. At least three more symbiotic stars exhibit broad absorption with blue edges faster than 1500 km s-1; high-ionization BALs have been reported in AS 304 (≡V4018 Sgr), while transient Balmer BALs have been reported in Z And and CH Cyg. These BAL-producing fast outflows can have wider opening angles than has been previously supposed. BAL symbiotics are short-time-scale laboratories for their giga-scale analogues, broad absorption line quasars (BALQSOs), which display a similarly wide range of ionization states in their winds.

Broad absorption line symbiotic stars: highly ionized species in the fast outflow from MWC 560

NASA Astrophysics Data System (ADS)

Lucy, Adrian B.; Knigge, Christian; Sokoloski, J. L.

2018-04-01

In symbiotic binaries, jets and disk winds may be integral to the physics of accretion onto white dwarfs from cool giants. The persistent outflow from symbiotic star MWC 560 (≡V694 Mon) is known to manifest as broad absorption lines (BALs), most prominently at the Balmer transitions. We report the detection of high-ionization BALs from C IV, Si IV, N V, and He II in International Ultraviolet Explorer spectra obtained on 1990 April 29 - 30, when an optical outburst temporarily erased the obscuring `iron curtain' of absorption troughs from Fe II and similar ions. The C IV and Si IV BALs reached maximum radial velocities at least 1000 km s-1 higher than contemporaneous Mg II and He II BALs; the same behaviors occur in the winds of quasars and cataclysmic variables. An iron curtain lifts to unveil high-ionization BALs during the P Cygni phase observed in some novae, suggesting by analogy a temporary switch in MWC 560 from persistent outflow to discrete mass ejection. At least three more symbiotic stars exhibit broad absorption with blue edges faster than 1500 km s-1; high-ionization BALs have been reported in AS 304 (≡V4018 Sgr), while transient Balmer BALs have been reported in Z And and CH Cyg. These BAL-producing fast outflows can have wider opening angles than has been previously supposed. BAL symbiotics are short-timescale laboratories for their giga-scale analogs, broad absorption line quasars (BALQSOs), which display a similarly wide range of ionization states in their winds.

Polarized Disk Emission from Herbig Ae/Be Stars Observed Using Gemini Planet Imager: HD 144432, HD 150193, HD 163296, and HD 169142

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monnier, John D.; Aarnio, Alicia; Adams, Fred C.

In order to look for signs of ongoing planet formation in young disks, we carried out the first J -band polarized emission imaging of the Herbig Ae/Be stars HD 150193, HD 163296, and HD 169142 using the Gemini Planet Imager, along with new H band observations of HD 144432. We confirm the complex “double ring” structure for the nearly face-on system HD 169142 first seen in H -band, finding the outer ring to be substantially redder than the inner one in polarized intensity. Using radiative transfer modeling, we developed a physical model that explains the full spectral energy distribution andmore » J - and H -band surface brightness profiles, suggesting that the differential color of the two rings could come from reddened starlight traversing the inner wall and may not require differences in grain properties. In addition, we clearly detect an elongated, off-center ring in HD 163296 (MWC 275), locating the scattering surface to be 18 au above the midplane at a radial distance of 77 au, co-spatial with a ring seen at 1.3 mm by ALMA linked to the CO snow line. Lastly, we report a weak tentative detection of scattered light for HD 150193 (MWC 863) and a non-detection for HD 144432; the stellar companion known for each of these targets has likely disrupted the material in the outer disk of the primary star. For HD 163296 and HD 169142, the prominent outer rings we detect could be evidence for giant planet formation in the outer disk or a manifestation of large-scale dust growth processes possibly related to snow-line chemistry.« less

First L-Band Interferometric Observations of a Young Stellar Object: Probing the Circumstellar Environment of MWC 419

NASA Astrophysics Data System (ADS)

Ragland, S.; Akeson, R. L.; Armandroff, T.; Colavita, M. M.; Danchi, W. C.; Hillenbrand, L. A.; Millan-Gabet, R.; Ridgway, S. T.; Traub, W. A.; Vasisht, G.; Wizinowich, P. L.

2009-09-01

We present spatially resolved K- and L-band spectra (at spectral resolution R = 230 and R = 60, respectively) of MWC 419, a Herbig Ae/Be star. The data were obtained simultaneously with a new configuration of the 85 m baseline Keck Interferometer. Our observations are sensitive to the radial distribution of temperature in the inner region of the disk of MWC 419. We fit the visibility data with both simple geometric and more physical disk models. The geometric models (uniform disk and Gaussian) show that the apparent size increases linearly with wavelength in the 2-4 μm wavelength region, suggesting that the disk is extended with a temperature gradient. A model having a power-law temperature gradient with radius simultaneously fits our interferometric measurements and the spectral energy distribution data from the literature. The slope of the power law is close to that expected from an optically thick disk. Our spectrally dispersed interferometric measurements include the Br γ emission line. The measured disk size at and around Br γ suggests that emitting hydrogen gas is located inside (or within the inner regions) of the dust disk.

Excitation Mechanism of O I Lines in Herbig Ae/Be Stars

NASA Astrophysics Data System (ADS)

Mathew, Blesson; Manoj, P.; Narang, Mayank; Banerjee, D. P. K.; Nayak, Pratheeksha; Muneer, S.; Vig, S.; Pramod Kumar, S.; Paul, K. T.; Maheswar, G.

2018-04-01

We have investigated the role of a few prominent excitation mechanisms viz. collisional excitation, recombination, continuum fluorescence, and Lyman beta fluorescence on the O I line spectra in Herbig Ae/Be stars. The aim is to understand which of them is the central mechanism that explains the observed O I line strengths. The study is based on an analysis of the observed optical spectra of 62 Herbig Ae/Be stars and near-infrared spectra of 17 Herbig Ae/Be stars. The strong correlation observed between the line fluxes of O I λ8446 and O I λ11287, as well as a high positive correlation between the line strengths of O I λ8446 and Hα suggest that Lyman beta fluorescence is the dominant excitation mechanism for the formation of O I emission lines in Herbig Ae/Be stars. Furthermore, from an analysis of the emission line fluxes of O I λλ7774, 8446, and comparing the line ratios with those predicted by theoretical models, we assessed the contribution of collisional excitation in the formation of O I emission lines.

Einstein X-ray observations of Herbig Ae/Be stars

NASA Technical Reports Server (NTRS)

Damiani, F.; Micela, G.; Sciortino, S.; Harnden, F. R., Jr.

1994-01-01

We have investigated the X-ray emission from Herbig Ae/Be stars, using the full set of Einstein Imaging Proportional Counter (IPC) observations. Of a total of 31 observed Herbig stars, 11 are confidently identified with X-ray sources, with four additonal dubious identifications. We have used maximum likelihood luminosity functions to study the distribution of X-ray luminosity, and we find that Be stars are significantly brighter in X-rays than Ae stars and that their X-ray luminosity is independent of projected rotational velocity v sin i. The X-ray emission is instead correlated with stellar bolometric luminosity and with effective temperature, and also with the kinetic luminosity of the stellar wind. These results seem to exclude a solar-like origin for the X-ray emission, a possibility suggested by the most recent models of Herbig stars' structure, and suggest an analogy with the X-ray emission of O (and early B) stars. We also observe correlations between X-ray luminosity and the emission at 2.2 microns (K band) and 25 microns, which strengthen the case for X-ray emission of Herbig stars originating in their circumstellar envelopes.

The embedded population around Herbig Ae/Be stars

NASA Astrophysics Data System (ADS)

Testi, L.; Stanga, R. M.; Natta, A.; Palla, F.; Prusti, T.; Baffa, C.; Hunt, L. K.; Lisi, F.

Herbig Ae/Be stars are intermediate mass young stars in the pre-main sequence phase of evolution. There are only few stars of this type known so far, and all of them seem to be relatively isolated, in contrast to their low mass counterparts, the T Tauri stars. A possible explanation of this fact is that other young stars formed near the known YSO are deeply embedded in the molecular cloud environment and are not detectable at optical wavelengths. We used the new ARcetri Near Infrared CAmera (ARNICA) to survey in the J, H and K bands the regions of sky around Herbig stars. The aim of this work is to identify embedded YSO and investigate the clustering properties of these young stars.

COMPACT DUST CONCENTRATION IN THE MWC 758 PROTOPLANETARY DISK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marino, S.; Casassus, S.; Perez, S.

2015-11-01

The formation of planetesimals requires that primordial dust grains grow from micron- to kilometer-sized bodies. Dust traps caused by gas pressure maxima have been proposed as regions where grains can concentrate and grow fast enough to form planetesimals, before radially migrating onto the star. We report new VLA Ka and Ku observations of the protoplanetary disk around the Herbig Ae/Be star MWC 758. The Ka image shows a compact emission region in the outer disk, indicating a strong concentration of big dust grains. Tracing smaller grains, archival ALMA data in band 7 continuum shows extended disk emission with an intensitymore » maximum to the northwest of the central star, which matches the VLA clump position. The compactness of the Ka emission is expected in the context of dust trapping, as big grains are trapped more easily than smaller grains in gas pressure maxima. We develop a nonaxisymmetric parametric model inspired by a steady-state vortex solution with parameters adequately selected to reproduce the observations, including the spectral energy distribution. Finally, we compare the radio continuum with SPHERE scattered light data. The ALMA continuum spatially coincides with a spiral-like feature seen in scattered light, while the VLA clump is offset from the scattered light maximum. Moreover, the ALMA map shows a decrement that matches a region devoid of scattered polarized emission. Continuum observations at a different wavelength are necessary to conclude whether the VLA-ALMA difference is an opacity or a real dust segregation.« less

Wind diagnostics and correlations with the near-infrared excess in Herbig Ae/Be stars

NASA Astrophysics Data System (ADS)

Corcoran, M.; Ray, T. P.

1998-03-01

Intermediate dispersion spectroscopic observations of 37 Herbig Ae/Be stars reveal that the equivalent widths of their [OI]lambda 6300 and Hα emission lines, are related to their near-infrared colours in the same fashion as the T-Tauri stars. Such a correlation strongly supports the idea that the winds from Herbig Ae/Be stars arise in the same manner as those from T-Tauri stars, i.e. through accretion driven mass-loss. We also find that the [OI]lambda 6300 line luminosity correlates better with excess infrared luminosity than with stellar luminosities, again supporting the idea that Herbig Ae/Be winds are accretion driven. If one includes the lower mass analogues of the Herbig Ae/Be stars with forbidden line emission, i.e. the classical T-Tauri stars, the correlation between mass-loss rate and infrared excess spans 5 orders of magnitude in luminosity and a range of masses from 0.5Msun to approximately 10Msun. Our observations therefore extend the findings of Cohen et al. (1989) and Cabrit et al. (1990) for low mass young stars and, taken in conjunction with other evidence (Corcoran & Ray 1997), strongly support the presence of circumstellar disks around intermediate mass stars with forbidden line emission. An implication of our findings is that the same outflow model must be applicable to these Herbig Ae/Be stars and the classical T Tauri stars. Based on observations made at the La Palma Observatory, the Caltech Submillimeter Observatory, and the European Southern Observatory/Max Planck Institute 2.2m Telescope.

Resolving the Circumstellar Environment of the Galactic B[e] Supergiant Star MWC 137 from Large to Small Scales

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kraus, Michaela; Nickeler, Dieter H.; Liimets, Tiina

The Galactic object MWC 137 has been suggested to belong to the group of B[e] supergiants. However, with its large-scale optical bipolar ring nebula and high-velocity jet and knots, it is a rather atypical representative of this class. We performed multiwavelength observations spreading from the optical to the radio regimes. Based on optical imaging and long-slit spectroscopic data, we found that the northern parts of the large-scale nebula are predominantly blueshifted, while the southern regions appear mostly redshifted. We developed a geometrical model consisting of two double cones. Although various observational features can be approximated with such a scenario, themore » observed velocity pattern is more complex. Using near-infrared integral-field unit spectroscopy, we studied the hot molecular gas in the vicinity of the star. The emission from the hot CO gas arises in a small-scale disk revolving around the star on Keplerian orbits. Although the disk itself cannot be spatially resolved, its emission is reflected by the dust arranged in arc-like structures and the clumps surrounding MWC 137 on small scales. In the radio regime, we mapped the cold molecular gas in the outskirts of the optical nebula. We found that large amounts of cool molecular gas and warm dust embrace the optical nebula in the east, south, and west. No cold gas or dust was detected in the north and northwestern regions. Despite the new insights into the nebula kinematics gained from our studies, the real formation scenario of the large-scale nebula remains an open issue.« less

Few Skewed Disks Found in First Closure-Phase Survey of Herbig Ae/Be Stars

NASA Astrophysics Data System (ADS)

Monnier, J. D.; Berger, J.-P.; Millan-Gabet, R.; Traub, W. A.; Schloerb, F. P.; Pedretti, E.; Benisty, M.; Carleton, N. P.; Haguenauer, P.; Kern, P.; Labeye, P.; Lacasse, M. G.; Malbet, F.; Perraut, K.; Pearlman, M.; Zhao, M.

2006-08-01

Using the three-telescope IOTA interferometer on Mount Hopkins, we report results from the first near-infrared (λ=1.65 μm) closure-phase survey of young stellar objects (YSOs). These closure phases allow us to unambiguously detect departures from centrosymmetry (i.e., skew) in the emission pattern from YSO disks on the scale of ~4 mas, expected from generic ``flared disk'' models. Six of 14 targets showed small, yet statistically significant nonzero closure phases, with largest values from the young binary system MWC 361-A and the (pre-main-sequence?) Be star HD 45677. Our observations are quite sensitive to the vertical structure of the inner disk, and we confront the predictions of the ``puffed-up inner wall'' models of Dullemond, Dominik, & Natta (DDN). Our data support disk models with curved inner rims because the expected emission appears symmetrically distributed around the star over a wide range of inclination angles. In contrast, our results are incompatible with the models possessing vertical inner walls because they predict extreme skewness (i.e., large closure phases) from the near-IR disk emission that is not seen in our data. In addition, we also present the discovery of mysterious H-band ``halos'' (~5%-10% of light on scales 0.01"-0.50") around a few objects, a preliminary ``parametric imaging'' study for HD 45677, and the first astrometric orbit for the young binary MWC 361-A.

Angular Momentum in Disk Wind Revealed in the Young Star MWC 349A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Qizhou; Claus, Brian; Watson, Linda

Disk winds are thought to play a critical role in star birth. As winds extract excess angular momentum from accretion disks, matter in the disk can be transported inward to the star to fuel mass growth. However, observational evidence of wind carrying angular momentum has been very limited. We present Submillimeter Array (SMA) observations of the young star MWC 349A in the H26 α and H30 α recombination lines. The high signal-to-noise ratios made possible by the maser emission process allow us to constrain the relative astrometry of the maser spots to milli-arcsecond precision. Previous observations of the H30 αmore » line with the SMA and the Plateau de Bure interferometer (PdBI) showed that masers are distributed in the disk and wind. Our new high-resolution observations of the H26 α line reveal differences in spatial distribution from that of the H30 α line. H26 α line masers in the disk are excited in a thin annulus with a radius of about 25 au, while the H30 α line masers are formed in a slightly larger annulus with a radius of 30 au. This is consistent with expectations for maser excitation in the presence of an electron density variation of approximately R {sup −4}. In addition, the H30 α and H26 α line masers arise from different parts in the wind. This difference is also expected from maser theory. The wind component of both masers exhibits line-of-sight velocities that closely follow a Keplerian law. This result provides strong evidence that the disk wind extracts significant angular momentum, thereby facilitating mass accretion in the young star.« less

On the inner disc structure of MWC480: evidence for asymmetries?

NASA Astrophysics Data System (ADS)

Jamialahmadi, N.; Lopez, B.; Berio, Ph.; Matter, A.; Flament, S.; Fathivavsari, H.; Ratzka, T.; Sitko, M. L.; Spang, A.; Russell, R. W.

2018-01-01

Studying the physical conditions structuring the young circumstellar discs is required for understanding the onset of planet formation. Of particular interest is the protoplanetary disc surrounding the Herbig star MWC480. The structure and properties of the circumstellar disc of MWC480 are studied by infrared interferometry and interpreted from a modelling approach. New observations are driving this study, in particular, some recent Very Large Telescope Interferometer (VLTI)/MIDI data acquired in 2013 December. Our one-component disc model could not reproduce simultaneously all our data: the spectral energy distribution, the near-infrared Keck Interferometer data and the mid-infrared data obtained with the MIDI instrument. In order to explain all measurements, one possibility is to add an asymmetry in our one-component disc model with the assumption that the structure of the disc of MWC480 has not varied with time. Several scenarios are tested, and the one considering the presence of an azimuthal bright feature in the inner component of the disc model provides a better fit of the data.

Hydrodynamical Simulations of the Jet in the Symbiotic Star MWC 560. 3; Application to X-ray Jets in Symbiotic Stars

NASA Technical Reports Server (NTRS)

Stute, Matthias; Sahai, Raghvendra

2007-01-01

In Papers I and II in this series, we presented hydrodynamical simulations of jet models with parameters representative of the symbiotic system MWC 560. These were simulations of a pulsed, initially underdense jet in a high-density ambient medium. Since the pulsed emission of the jet creates internal shocks and since the jet velocity is very high, the jet bow shock and the internal shocks are heated to high temperatures and should therefore emit X-ray radiation. In this paper, we investigate in detail the X-ray properties of the jets in our models. We have focused our study on the total X-ray luminosity and its temporal variability, the resulting spectra, and the spatial distribution of the emission. Temperature and density maps from our hydrodynamical simulations with radiative cooling presented in the second paper are used, together with emissivities calculated with the atomic database ATOMDB. The jets in our models show extended and variable X-ray emission, which can be characterized as a sum of hot and warm components with temperatures that are consistent with observations of CH Cyg and R Aqr. The X-ray spectra of our model jets show emission-line features that correspond to observed features in the spectra of CH Cyg. The innermost parts of our pulsed jets show iron line emission in the 6.4-6.7 keV range, which may explain such emission from the central source in R Aqr. We conclude that MWC 560 should be detectable with Chandra or XMM-Newton, and such X-ray observations will prove crucial for understanding jets in symbiotic stars.

Deciphering the X-ray Emission of the Nearest Herbig Ae Star

NASA Technical Reports Server (NTRS)

Skinner, Stephen L.

2004-01-01

In this research program, we obtained and analyzed an X-ray observation of the young nearby intermediate mass pre-main sequence star HD 104237 using the XMM-Newton space-based observatory. The observation was obtained on 17 Feb. 2002. This observation yielded high-quality X-ray images, spectra, and timing data which provided valuable information on the physical processes responsible for the X-ray emission. This star is a member of the group of so-called Herbig Ae/Be stars, which are young intermediate mass (approx. 2 - 4 solar masses) pre-main sequence (PMS) stars a few million years old that have not yet begun core hydrogen burning. The objective of the XMM-Newton observation was to obtain higher quality data than previously available in order to constrain possible X-ray emission mechanisms. The origin of the X-ray emission from Herbig Ae/Be stars is not yet known. These intermediate mass PMS stars lie on radiative tracks and are not expected to emit X-rays via solar-like magnetic processes, nor are their winds powerful enough to produce X-rays by radiative wind shocks as in more massive O-type stars. The emission could originate in unseen low-mass companions, or it may be intrinsic to the Herbig stars themselves if they still have primordial magnetic fields or can sustain magnetic activity via a nonsolar dynamo.

Mid Infrared Hydrogen Recombination Line Emission from the Maser Star MWC 349A

NASA Technical Reports Server (NTRS)

Smith, Howard A.; Strelnitski, V.; Miles, J. W.; Kelly, D. M.; Lacy, J. H.

1997-01-01

We have detected and spectrally resolved the mid-IR hydrogen recombination lines H6(alpha)(12.372 micrometers), H7(alpha)(19.062 micrometers), H7(beta)(l1.309 micrometers) and H8(gamma)(12.385 micrometers) from the star MWC349A. This object has strong hydrogen maser emission (reported in the millimeter and submillimeter hydrogen recombination lines from H36(alpha) to H21(alpha)) and laser emission (reported in the H15(alpha), H12(alpha) and H10(alpha) lines). The lasers/masers are thought to arise predominantly in a Keplerian disk around the star. The mid-IR lines do not show evident signs of lasing, and can be well modeled as arising from the strong stellar wind, with a component arising from a quasi-static atmosphere around the disk, similar to what is hypothesized for the near IR (less than or equal to 4 micrometers) recombination lines. Since populations inversions in the levels producing these mid-IR transitions are expected at densities up to approximately 10(exp 11)/cu cm, these results imply either that the disk does not contain high-density ionized gas over long enough path lengths to produce a gain approximately 1, and/or that any laser emission from such regions is small compared to the spontaneous background emission from the rest of the source as observed with a large beam. The results reinforce the interpretation of the far-IR lines as true lasers.

Two-Decade Monitoring of MWC349 in Optical and Radio: New Results

NASA Astrophysics Data System (ADS)

Thomashow, Eydon; Jorgenson, Regina A.; Strelnitski, Vladimir; Walker, Gary; Maria Mitchell Observatory (MMO) Research Experiences for Undergraduate (REU) Interns, 2017

2018-01-01

Maria Mitchell Observatory (MMO) has completed the two-decade long monitoring of MWC 349 in the optical and radio domains. This poster presentation will be primarily devoted to the new results obtained by optical photometry with broad and narrow band filters and observations of the variability in the masing H30 radio line during the observational season of 2017. The H30 emission arises in the circumstellar disk of the MWC 349A component of the visual double star (with 2.4 arcsec separation between the A and B components). Variable optical emission is also believed to be due to star A. By combining our optical observations with earlier MMO observations, we not only confirmed the previously known quasi-period of ~230 days, but confirmed a second period of ~700 days. One of the most interesting results of radio monitoring is the long-term variability of the systemic radial velocity of star A, as determined through averaging the radial velocities of the two masing peaks arising in the circumstellar disk. This may be the first case where a possible hidden close companion of a star (a lower mass star or a massive protoplanet) is detected by monitoring the radial velocity of the star via the spectral line radiation from its disk. E.T. completed this project as a 2017 MMO NSF REU intern and would like to thank the other interns for their help in conducting the optical observations. This project was supported in part by the NSF REU grant AST-1358980 and by the Nantucket Maria Mitchell Association.

The One Micron Fe II Lines in Active Galaxies and Emission Line Stars

NASA Astrophysics Data System (ADS)

Rudy, R. J.; Mazuk, S.; Puetter, R. C.; Hamann, F. W.

1999-05-01

The infrared multiplet of Fe II lines at 0.9997, 1.0501, 1.0863, and 1.1126 microns are particularly strong relative to other red and infrared Fe II features. They reach their greatest strength, relative to the hydrogen lines, in the Seyfert 1 galaxy I Zw 1, and are a common, although not ubiquitous feature, in the broad line regions of active galaxies. In addition, they are seen in a diverse assortment of Galactic sources including young stars, Herbig Ae and Be stars, luminous blue variables, proto-planetary nebulae, and symbiotic novae. They are probably excited by Lyman alpha florescence but the exact path of the cascade to their upper levels is uncertain. They arise in dense, sheltered regions of low ionization and are frequently observed together with the infrared Ca II triplet and the Lyman beta excited O I lines 8446 and 11287. The strengths of the four Fe II features, relative to each other, are nearly constant from object to object suggesting a statistical population of their common upper multiplet. Their intensities, in comparison to the Paschen lines, indicate that they can be important coolants for regions with high optical depths in the hydrogen lines. In addition to I Zw 1 and other active galaxies, we present spectra for the Galactic sources MWC 17, MWC 84, MWC 340, MWC 922, PU Vul, and M 1-92. We review the status of the Fe II observations and discuss the excitation process and possible implications. This work was supported by the IR&D program of the Aerospace Corporation. RCP and FWH acknowledge support from NASA.

Report on the Workshop Herbig Ae/Be Stars: The Missing Link in Star Formation

NASA Astrophysics Data System (ADS)

de Wit, W.-J.; Oudmaijer, R. D.; van den Ancker, M. E.; Calvet, N.

2014-09-01

The workshop highlighted the many recent advances within the field of Herbig Ae/Be stars and the close links to star and planet formation. Topics such as magnetospheric accretion and the evolution of dust in discs, the structure of circumstellar discs and the role of walls and gaps and their links to planet formation from many observational aspects were covered. The workshop was dedicated to the life and works of George H. Herbig, who sadly passed away at the end of last year.

Peculiarities of the circumstellar envelopes of some Herbig Ae/Be stars

NASA Astrophysics Data System (ADS)

Pogodin, M. A.

1985-10-01

The results of a spectral and photometric investigation of nine Herbig Ae/Be stars in the visible region of the spectrum in the period from 1978 to 1982 are presented. Certain physical and kinematic parameters of the circumstellar envelopes of the investigated objects are determined on the basis of the observational material obtained and Sobolev's (1947) probabilistic method for moving envelopes. It is shown that the observed spectral characteristics of the envelopes of Herbig Ae/Be stars and their variability can be explained by using models of extended isothermal envelopes with varying structural-kinematic parameters. The existence of a correlation between the amount of dust IR excess and the presence of signs of H2O absorption in the spectra of the investigated objects is noted.

Improved Constraints on the Disk around MWC 349A from the 23 m LBTI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sallum, S.; Eisner, J. A.; Hinz, P. M.

2017-07-20

We present new spatially resolved observations of MWC 349A from the Large Binocular Telescope Interferometer (LBTI), a 23 m baseline interferometer made up of two, co-mounted 8 m telescopes. MWC 349A is a B[e] star with an unknown evolutionary state. Proposed scenarios range from a young stellar object, to a B[e] supergiant, to a tight binary system. Radio continuum and recombination line observations of this source revealed a sub-arcsecond bipolar outflow surrounding an ∼100 mas circumstellar disk. Follow-up infrared studies detected the disk, and suggested that it may have skew and an inner clearing. Our new infrared interferometric observations, whichmore » have more than twice the resolution of previously published data sets, support the presence of both skew and a compact infrared excess. They rule out inner clearings with radii greater than ∼14 mas. We show the improvements in disk parameter constraints provided by LBTI, and discuss the inferred disk parameters in the context of the posited evolutionary states for MWC 349A.« less

Parameterizing the dust around Herbig Ae/Be stars: Multiwavelength imaging radiative transfer modeling, and near-infrared instrumentation

NASA Astrophysics Data System (ADS)

Doering, Ryan Lee

Herbig Ae/Be stars are considered the intermediate-mass analogs of the low-mass pre-main sequence T Tauri stars. Observations reveal that they are surrounded by dusty matter that may provide the solid-state material for building planets. Determining the dust parameters provides constraints for planet formation theory, and yields information about the matter around intermediate-mass stars as they approach the main sequence. In this dissertation, I present the results of a multiwavelength imaging and radiative transfer modeling study of Herbig Ae/Be stars, and a near-infrared instrumentation project, with the aim of parameterizing the dust in these systems. The Hubble Space Telescope was used to search for optical light scattered by dust in a sample of young stars. This survey provided the first scattered-light image of the circumstellar environment around the Herbig Ae/Be star HD 97048. Structure is observed in the dust distribution similar to that seen in other Herbig Ae/Be systems. A ground-based near-infrared imaging study of Herbig Ae/ Be candidates was also carried out. Photometry was collected for spectral energy distribution construction, and binary candidates were resolved. A mid- infrared image of the low-mass debris system, AU Microscopii, is presented, being relevant to the study of Herbig Ae/Be stars. Detailed dust modeling of HD 97048 and HD 100546 was carried out with a two- component geometry consisting of a flared disk and an extended envelope. The models achieve a reasonable global fit to the spectral energy distributions, and produce images with the desired geometry. The disk midplane densities are found to go as r -0.5 and r -1.8 , giving disk dust masses of 3.0 × 10^-4 and 5.9 × 10 ^5 [Special characters omitted.] for HD 97048 and HD 100546, respectively. A gas-to-dust mass ratio lower limit of 3.2 was calculated for HD 97048. In order to advance the imaging capabilities available for observations of Herbig Ae/Be stars, I have participated in

The (BETA) Pictoris Phenomenon Among Herbig Ae/Be Stars

NASA Technical Reports Server (NTRS)

Grady, C. A.; Perez, M. R.; Talavera, A.; Bjorkman, K. S.; deWinter, D.; The, P.-S.; Molster, F. J.; vandenAncker, M. E.; Sitko, M. L.; Morrison, N. D.;

Infrared Observations of FS CMa Stars

NASA Astrophysics Data System (ADS)

Sitko, Michael L.; Russell, R. W.; Lynch, D. K.; Grady, C. A.; Hammel, H. B.; Beerman, L. C.; Day, A. N.; Huelsman, D.; Rudy, R. J.; Brafford, S. M.; Halbedel, E. M.

2009-01-01

A subset of non-supergiant B[e] stars has recently been recognized as forming a fairly unique class of objects with very strong emission lines, infrared excesses, and locations not associated with star formation. The exact evolutionary state of these stars, named for the prototype FS CMa, is uncertain, and they have often been classified as isolated Herbig AeBe stars. We present infrared observations of two of these stars, HD 45677 (FS CMa), HD 50138 (MWC 158), and the candidate FS CMa star HD 190073 (V1295 Aql) that span over a decade in time. All three exhibit an emission band at 10 microns due to amorphous silicates, confirming that much (if not all) of the infrared excess is due to dust. HD 50138 is found to exhibit 20% variability between 3-13 microns that resembles that found in pre-main sequence systems (HD 163296 and HD 31648). HD 45677, despite large changes at visual wavelengths, has remained relatively stable in the infrared. To date, no significant changes have been observed in HD 190073. This work is supported in part by NASA Origins of Solar Systems grant NAG5-9475, NASA Astrophysics Data Program contract NNH05CD30C, and the Independent Research and Development program at The Aerospace Corporation.

Using the MWC model to describe heterotropic interactions in hemoglobin

PubMed Central

Rapp, Olga

2017-01-01

Hemoglobin is a classical model allosteric protein. Research on hemoglobin parallels the development of key cooperativity and allostery concepts, such as the ‘all-or-none’ Hill formalism, the stepwise Adair binding formulation and the concerted Monod-Wymann-Changuex (MWC) allosteric model. While it is clear that the MWC model adequately describes the cooperative binding of oxygen to hemoglobin, rationalizing the effects of H+, CO2 or organophosphate ligands on hemoglobin-oxygen saturation using the same model remains controversial. According to the MWC model, allosteric ligands exert their effect on protein function by modulating the quaternary conformational transition of the protein. However, data fitting analysis of hemoglobin oxygen saturation curves in the presence or absence of inhibitory ligands persistently revealed effects on both relative oxygen affinity (c) and conformational changes (L), elementary MWC parameters. The recent realization that data fitting analysis using the traditional MWC model equation may not provide reliable estimates for L and c thus calls for a re-examination of previous data using alternative fitting strategies. In the current manuscript, we present two simple strategies for obtaining reliable estimates for MWC mechanistic parameters of hemoglobin steady-state saturation curves in cases of both evolutionary and physiological variations. Our results suggest that the simple MWC model provides a reasonable description that can also account for heterotropic interactions in hemoglobin. The results, moreover, offer a general roadmap for successful data fitting analysis using the MWC model. PMID:28793329

The First Simultaneous X-Ray/Radio Detection of the First Be/BH System MWC 656

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ribó, M.; Paredes, J. M.; Marcote, B.

2017-02-01

MWC 656 is the first known Be/black hole (BH) binary system. Be/BH binaries are important in the context of binary system evolution and sources of detectable gravitational waves because they are possible precursors of coalescing neutron star/BH binaries. X-ray observations conducted in 2013 revealed that MWC 656 is a quiescent high-mass X-ray binary (HMXB), opening the possibility to explore X-ray/radio correlations and the accretion/ejection coupling down to low luminosities for BH HMXBs. Here we report on a deep joint Chandra /VLA observation of MWC 656 (and contemporaneous optical data) conducted in 2015 July that has allowed us to unambiguously identifymore » the X-ray counterpart of the source. The X-ray spectrum can be fitted with a power law with Γ ∼ 2, providing a flux of ≃4 × 10{sup −15} erg cm{sup −2} s{sup −1} in the 0.5–8 keV energy range and a luminosity of L {sub X} ≃ 3 × 10{sup 30} erg s{sup −1} at a 2.6 kpc distance. For a 5 M{sub ⊙} BH this translates into ≃5 × 10{sup −9} L {sub Edd}. These results imply that MWC 656 is about 7 times fainter in X-rays than it was two years before and reaches the faintest X-ray luminosities ever detected in stellar-mass BHs. The radio data provide a detection with a peak flux density of 3.5 ± 1.1 μ Jy beam{sup −1}. The obtained X-ray/radio luminosities for this quiescent BH HMXB are fully compatible with those of the X-ray/radio correlations derived from quiescent BH low-mass X-ray binaries. These results show that the accretion/ejection coupling in stellar-mass BHs is independent of the nature of the donor star.« less

Searching for Hα emitting sources around MWC 758. SPHERE/ZIMPOL high-contrast imaging

NASA Astrophysics Data System (ADS)

Huélamo, N.; Chauvin, G.; Schmid, H. M.; Quanz, S. P.; Whelan, E.; Lillo-Box, J.; Barrado, D.; Montesinos, B.; Alcalá, J. M.; Benisty, M.; Gregorio-Monsalvo, I. de; Mendigutía, I.; Bouy, H.; Merín, B.; de Boer, J.; Garufi, A.; Pantin, E.

2018-05-01

Context. MWC 758 is a young star surrounded by a transitional disk. The disk shows an inner cavity and spiral arms that could be caused by the presence of protoplanets. Recently, a protoplanet candidate has been detected around MWC 758 through high-resolution L'-band observations. The candidate is located inside the disk cavity at a separation of 111 mas from the central star, and at an average position angle of 165.5°. Aims: We aim at detecting accreting protoplanet candidates within the disk of MWC 758 through angular spectral differential imaging (ASDI) observations in the optical regime. In particular, we explore the emission at the position of the detected planet candidate. Methods: We have performed simultaneous adaptive optics observations in the Hα line and the adjacent continuum using SPHERE/ZIMPOL at the Very Large Telescope (VLT). Results: The data analysis does not reveal any Hα signal around the target. The derived contrast curve in the B_Ha filter allows us to derive a 5σ upper limit of 7.6 mag at 111 mas, the separation of the previously detected planet candidate. This contrast translates into a Hα line luminosity of LHα ≲ 5×10-5 L⊙ at 111 mas. Assuming that LHα scales with Lacc as in classical T Tauri stars (CTTSs) as a first approximation, we can estimate an accretion luminosity of Lacc < 3.7 × 10-4 L⊙ for the protoplanet candidate. For the predicted mass range of MWC 758b, 0.5-5 MJup, this implies accretion rates smaller than Ṁ < 3.4 × (10-8-10-9)M⊙ yr-1, for an average planet radius of 1.1 RJup. Therefore, our estimates are consistent with the predictions of accreting circumplanetary accretion models for Rin = 1RJup. The ZIMPOL line luminosity is consistent with the Hα upper limit predicted by these models for truncation radii ≲3.2 RJup. Conclusions: The non-detection of any Hα emitting source in the ZIMPOL images does not allow us to unveil the nature of the L' detected source. Either it is a protoplanet candidate or a

V694 Mon (MWC 560) spectroscopy requested

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2017-05-01

The observing campaign from 2016 on V694 Mon (MWC 560) (AAVSO Alert Notice 538) has been continued, but with different requirements. Photometry is no longer specifically requested on a regular basis (although ongoing observations that do not interfere with other obligations are welcome). Spectroscopy on a cadence of a week or two is requested to monitor changes in the disk outflow. Investigator Adrian Lucy writes: "Adrian Lucy and Dr. Jeno Sokoloski (Columbia University) have requested spectroscopic monitoring of the broad-absorption-line symbiotic star V694 Mon (MWC 560), as a follow-up to coordinated multi-wavelength observations obtained during its recent outburst (ATel #8653, #8832, #8957; #10281). This system is a perfect place in which to study the relationship between an accretion disk and disk winds/jets, and a high-value target for which even low-resolution spectra can be extraordinarily useful...Optical brightening in MWC 560 tends to predict higher-velocity absorption, but sometimes jumps in absorption velocity also appear during optical quiescence (e.g., Iijima 2001, ASPCS, 242, 187). If such a velocity jump occurs during photometric quiescence, it may prompt radio observations to confirm and test the proposed outflow origin for recently-discovered flat-spectrum radio emission (Lucy et al. ATel #10281)...Furthermore, volunteer spectroscopic monitoring of this system has proved useful in unpredictable ways. For example, 'amateur' spectra obtained by Somogyi Péter in 2015 December demonstrated that the velocity of absorption was very low only a month before an optical outburst peak prompted absorption troughs up to 3000 km/s, which constrains very well the timing of the changes to the outflow to a degree that would not have been otherwise possible. Any resolution can be useful. A wavelength range that can accommodate a blueshift of at least 140 angstroms (6000 km/s) from the rest wavelengths of H-alpha at 6562 angstroms and/or H-beta at 4861 angstroms is

Observations of V694 Mon (MWC 560) requested for Chandra campaign

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2016-02-01

Dr. Jeno Sokoloski (Columbia University) and Mr. Adrian Lucy (graduate student, Columbia University) have requested AAVSO observations of the jet-driving symbiotic star V694 Mon (MWC 560), which is in outburst, in support of upcoming Chandra observations to investigate the state of the inner accretion disk during this outburst. Beginning now and continuing through April 2016, Sokoloski writes, "multi-band photometry (UBVRI, but especially UBV), spectroscopy, and minute-time-resolution light curves of the optical flickering are requested. Series of exposures in B or V will be very interesting." Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

Disk Evaporation in Star Forming Regions

NASA Technical Reports Server (NTRS)

Hollenbach, David; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

Young stars produce sufficient ultraviolet photon luminosity and mechanical luminosity in their winds to significantly affect the structure and evolution of the accretion disks surrounding them. The Lyman continuum photons create a nearly static, ionized, isothermal 10(exp 4) K atmosphere forms above the neutral disk at small distances from the star. Further out, they create a photoevaporative flow which relatively rapidly destroys the disk. The resulting slow (10-50 km/s) ionized outflow, which persists for approx. greater than 10(exp 5) years for disk masses M(sub d) approx. 0.3M(sub *), may explain the observational characteristics of many ultracompact HII regions. We compare model results to the observed radio free-free spectra and luminosities of ultracompact HII regions and to the interesting source MWC349, which is observed to produce hydrogen masers. We apply the results to Ae and Be stars in order to determine the lifetimes of disks around such stars. We also apply the results to the early solar nebula to explain the the dispersal of the solar nebula and the differences in hydrogen content in the giant planets. Finally, we model the small bright objects ("proplyds") observed in the Orion Nebula as disks around young, low mass stars which are externally illuminated by the UV photons from the nearby massive star Theta(sup 1) C.

High-Contrast NIR Polarization Imaging of MWC480

NASA Technical Reports Server (NTRS)

McElwain, M. W.; Kusakabe, N.; Hashimoto, J.; Kudo, T.; Kandori, R.; Miyama, S.; Morino, J.-I.; Suto, H.; Suzuki, R.; Tamura, M.;

Reprocessing of Archival Direct Imaging Data of Herbig Ae/Be Stars

NASA Astrophysics Data System (ADS)

Safsten, Emily; Stephens, Denise C.

2017-01-01

Herbig Ae/Be (HAeBe) stars are intermediate mass (2-10 solar mass) pre-main sequence stars with circumstellar disks. They are the higher mass analogs of the better-known T Tauri stars. Observing planets within these young disks would greatly aid in understanding planet formation processes and timescales, particularly around massive stars. So far, only one planet, HD 100546b, has been confirmed to orbit a HAeBe star. With over 250 HAeBe stars known, and several observed to have disks with structures thought to be related to planet formation, it seems likely that there are as yet undiscovered planetary companions within the circumstellar disks of some of these young stars.Direct detection of a low-luminosity companion near a star requires high contrast imaging, often with the use of a coronagraph, and the subtraction of the central star's point spread function (PSF). Several processing algorithms have been developed in recent years to improve PSF subtraction and enhance the signal-to-noise of sources close to the central star. However, many HAeBe stars were observed via direct imaging before these algorithms came out. We present here current work with the PSF subtraction program PynPoint, which employs a method of principal component analysis, to reprocess archival images of HAeBe stars to increase the likelihood of detecting a planet in their disks.

Parameterizing the Dust Around Herbig Ae/Be Stars: Multiwavelength Imaging, Radiative Transfer Modeling, and Near-Infrared Instrumentation

NASA Astrophysics Data System (ADS)

Doering, Ryan L.

2009-01-01

Determining Herbig Ae/Be star dust parameters provides constraints for planet formation theory, and yields information about the matter around intermediate-mass stars as they approach the main sequence. In this dissertation talk, I present the results of a multiwavelength imaging and radiative transfer modeling study of Herbig Ae/Be stars, and a near-infrared instrumentation project, with the aim of parameterizing the dust in these systems. The Hubble Space Telescope was used to search for optical light scattered by dust in a sample of young stars. This survey provided the first scattered-light image of the circumstellar environment around the Herbig Ae/Be star HD 97048. Structure is observed in the dust distribution similar to that seen in other Herbig Ae/Be systems. A ground-based near-infrared imaging study of Herbig Ae/Be candidates was also carried out. Photometry was collected for spectral energy distribution construction, and binary candidates were resolved. Detailed dust modeling of HD 97048 and HD 100546 was carried out with a two-component geometry consisting of a flared disk and an extended envelope. The models achieve a reasonable global fit to the spectral energy distributions, and produce images with the desired geometry. The disk midplane densities are found to go as r-0.5 and r-1.8, giving disk dust masses of 3.0 x 10-4 and 5.9 x 10-5 Msun for HD 97048 and HD 100546, respectively. A gas-to-dust mass ratio lower limit of 3.2 was calculated for HD 97048. Furthermore, I have participated in the development of the WIYN High Resolution Infrared Camera. The instrument operates in the near-infrared ( 0.8 - 2.5 microns), includes 13 filters, and has a pixel size of 0.1 arcsec, resulting in a field of view of 3 arcmin x 3 arcmin. An angular resolution of 0.25 arcsec is anticipated. I provide an overview of the instrument and report performance results.

Determining the Frequency and Structure of Mass Flows Around Herbig Ae/Be Stars

NASA Astrophysics Data System (ADS)

Johns-Krull, Christopher

One of the key scientific goals being pursued by NASA, as outlined in its Strategic Plan, is to understand how individual stars form and how those processes that affect star formation also impact the formation of planetary systems. Ultimately, we wish to know how the Earth formed and how life arose on our planet. This knowledge will lead to an understanding of whether there are other life bearing planets in our galaxy and throughout the Universe. In pursuit of this knowledge, we must consider the process of star and planetary system formation for stars of all masses so that we can test and refine our theories related to the origin of life on our planet. It is now well established that planets form in disks of gas and dust that surround newly formed stars. Key factors that determine the structure and lifetime of these disks, thereby determining the likelihood of planet formation, include how rapidly the disk material accretes onto the central star or is expelled in powerful outflows of material that are routinely observed from young stars. It is the goal of this project to study the prevalence of outflows and accretion signature in a class of young stars known as Herbig Ae/Be stars. These stars are higher mass than stars like the Sun; however, they possess unique qualities that allows us to use the study of their accretion and outflow characteristics to test our understanding of these phenomena on solar like stars. This project will combine archival International Ultraviolet Explorer (IUE) satellite data and archival Far-Ultraviolet Spectroscopic Explorer (FUSE) satellite data with spectra at other wavelengths to robustly study the incidence of accretion and outflow signatures around Herbig Ae/Be stars. The IUE and FUSE data are also sensitive to the temperature of these flows and will allow us to understand their overall structure much more completely. This overall project will comprise the PhD thesis research of a graduate student at Rice University. The budget

Dust Around Herbig Ae Stars: Additional Constraints from their Photometric and Polarimetric Variability

NASA Technical Reports Server (NTRS)

Krivova, N. A.; Ilin, V. B.; Fischer, O.

1996-01-01

For the Herbig Ae stars with Algol-like minima (UX Ori, WW Vul, etc), the effects of circumstellar dust include: excess infrared emission, anomalous ultraviolet extinction, the 'blueing' of the stars in minima accompanying by an increase of intrinsic polarization. Using a Monte-Carlo code for polarized radiation transfer we have simulated these effects and compared the results obtained for different models with the observational data available. We found that the photometric and polarimetric behavior of the stars provided essential additional constraints on the circumstellar dust models. The models with spheroidal shell geometry and compact (non-fluffy) dust grains do not appear to be able to explain all the data.

A symmetric bipolar nebula around MWC 922.

PubMed

Tuthill, P G; Lloyd, J P

2007-04-13

We report regular and symmetric structure around dust-enshrouded Be star MWC 922 obtained with infrared imaging. Biconical lobes that appear nearly square in aspect, forming this "Red Square" nebula, are crossed by a series of rungs that terminate in bright knots or "vortices," and an equatorial dark band crossing the core delimits twin hyperbolic arcs. The intricate yet cleanly constructed forms that comprise the skeleton of the object argue for minimal perturbation from global turbulent or chaotic effects. We also report the presence of a linear comb structure, which may arise from optically projected shadows of a periodic feature in the inner regions, such as corrugations in the rim of a circumstellar disk. The sequence of nested polar rings draws comparison with the triple-ring system seen around the only naked-eye supernova in recent history: SN1987A.

A search for strong, ordered magnetic fields in Herbig Ae/Be stars

NASA Astrophysics Data System (ADS)

Wade, G. A.; Bagnulo, S.; Drouin, D.; Landstreet, J. D.; Monin, D.

2007-04-01

The origin of magnetic fields in intermediate- and high-mass stars is fundamentally a mystery. Clues towards solving this basic astrophysical problem can likely be found at the pre-main-sequence (PMS) evolutionary stage. With this work, we perform the largest and most sensitive search for magnetic fields in PMS Herbig Ae/Be (HAeBe) stars. We seek to determine whether strong, ordered magnetic fields, similar to those of main-sequence Ap/Bp stars, can be detected in these objects, and if so, to determine the intensities, geometrical characteristics, and statistical incidence of such fields. 68 observations of 50 HAeBe stars have been obtained in circularly polarized light using the FORS1 spectropolarimeter at the ESO VLT. An analysis of both Balmer and metallic lines reveals the possible presence of weak longitudinal magnetic fields in photospheric lines of two HAeBe stars, HD 101412 and BF Ori. Results for two additional stars, CPD-53 295 and HD 36112, are suggestive of the presence of magnetic fields, but no firm conclusions can be drawn based on the available data. The intensity of the longitudinal fields detected in HD 101412 and BF Ori suggest that they correspond to globally ordered magnetic fields with surface intensities of order 1 kG. On the other hand, no magnetic field is detected in 4 other HAeBe stars in our sample in which magnetic fields had previously been confirmed. Monte Carlo simulations of the longitudinal field measurements of the undetected stars allow us to place an upper limit of about 300 G on the general presence of aligned magnetic dipole magnetic fields, and of about 500 G on perpendicular dipole fields. Taking into account the results of our survey and other published results, we find that the observed bulk incidence of magnetic HAeBe stars in our sample is 8-12 per cent, in good agreement with that of magnetic main-sequence stars of similar masses. We also find that the rms longitudinal field intensity of magnetically detected HAe

DIAGNOSING MASS FLOWS AROUND HERBIG Ae/Be STARS USING THE HE I λ10830 LINE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cauley, P. Wilson; Johns-Krull, Christopher M., E-mail: pcauley@wesleyan.edu, E-mail: cmj@rice.edu

2014-12-20

We examine He I λ10830 profile morphologies for a sample of 56 Herbig Ae/Be stars (HAEBES). We find significant differences between HAEBES and classical T-Tauri stars (CTTS) in the statistics of both blueshifted absorption (i.e., mass outflows) and redshifted absorption features (i.e., mass infall or accretion). Our results suggest that, in general, Herbig Be (HBe) stars do not accrete material from their inner disks in the same manner as CTTS, which are believed to accrete material via magnetospheric accretion, whereas Herbig Ae (HAe) stars generally show evidence for magnetospheric accretion. We find no evidence in our sample of narrow blueshiftedmore » absorption features, which are typical indicators of inner disk winds and are common in He I λ10830 profiles of CTTS. The lack of inner-disk-wind signatures in HAEBES, combined with the paucity of detected magnetic fields on these objects, suggests that accretion through large magnetospheres that truncate the disk several stellar radii above the surface is not as common for HAe and late-type HBe stars as it is for CTTS. Instead, evidence is found for smaller magnetospheres in the maximum redshifted absorption velocities in our HAEBE sample. These velocities are, on average, a smaller fraction of the system escape velocity than is found for CTTS, suggesting accretion is taking place closer to the star. Smaller magnetospheres, and evidence for boundary layer accretion in HBe stars, may explain the less common occurrence of redshifted absorption in HAEBES. Evidence is found that smaller magnetospheres may be less efficient at driving outflows compared to CTTS magnetospheres.« less

Resolving the Circumstellar Environment of the Galactic B[e] Supergiant Star MWC 137 from Large to Small Scales

NASA Astrophysics Data System (ADS)

Kraus, Michaela; Liimets, Tiina; Cappa, Cristina E.; Cidale, Lydia S.; Nickeler, Dieter H.; Duronea, Nicolas U.; Arias, Maria L.; Gunawan, Diah S.; Oksala, Mary E.; Borges Fernandes, Marcelo; Maravelias, Grigoris; Curé, Michel; Santander-García, Miguel

2017-11-01

The Galactic object MWC 137 has been suggested to belong to the group of B[e] supergiants. However, with its large-scale optical bipolar ring nebula and high-velocity jet and knots, it is a rather atypical representative of this class. We performed multiwavelength observations spreading from the optical to the radio regimes. Based on optical imaging and long-slit spectroscopic data, we found that the northern parts of the large-scale nebula are predominantly blueshifted, while the southern regions appear mostly redshifted. We developed a geometrical model consisting of two double cones. Although various observational features can be approximated with such a scenario, the observed velocity pattern is more complex. Using near-infrared integral-field unit spectroscopy, we studied the hot molecular gas in the vicinity of the star. The emission from the hot CO gas arises in a small-scale disk revolving around the star on Keplerian orbits. Although the disk itself cannot be spatially resolved, its emission is reflected by the dust arranged in arc-like structures and the clumps surrounding MWC 137 on small scales. In the radio regime, we mapped the cold molecular gas in the outskirts of the optical nebula. We found that large amounts of cool molecular gas and warm dust embrace the optical nebula in the east, south, and west. No cold gas or dust was detected in the north and northwestern regions. Despite the new insights into the nebula kinematics gained from our studies, the real formation scenario of the large-scale nebula remains an open issue. Based on observations collected with (1) the ESO VLT Paranal Observatory under programs 094.D-0637(B) and 097.D-0033(A), (2) the MPG 2.2 m telescope at La Silla Observatory, Chile, under programs 096.A-9030(A) and 096.A-9039(A), (3) the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the

PDS 144: The First Confirmed Herbig Ae-Herbig Ae Wide Binary

NASA Technical Reports Server (NTRS)

Hornbeck, J. B.; Grady, C. A.; Perrin, M. D.; Wisniewski, J. P.; Tofflemire, B. M.; Brown, A.; Holtzman, J. A.; Arraki, K.; Hamaguchi, K.; Woodgate, B.;

PAH Emission from Disks around Intermediate-Mass Stars: The Peculiar Aroma of Hydrocarbons Orbiting Herbig Ae/Be Stars

NASA Astrophysics Data System (ADS)

Keller, L. D.; Sloan, G. C.

2009-12-01

Over half of the intermediate-mass young stellar objects in the Galaxy (e.g. Herbig Ae/Be stars or HAeBe) have high-contrast emission in the mid-infrared spectral features of polycyclic aromatic hydrocarbons (PAHs) above the continuum produced by thermal emission from dust in the circumstellar disks. We have examined the PAH emission in detail for 30 HAeBe stars observed with the Spitzer IRS. We have identified some trends that, should they survive in a larger sample of HAeBe stars, will allow us to infer large-scale disk geometry (both inner and outer) and the degree of photo-processing of organic molecular material in HAeBe disks: HAeBe stars apparently have distinctive PAH spectra among the many other astronomical environments that are characterized by strong PAH emission; strong PAH emission is not necessarily an indicator of a particular disk geometry; PAH spectra of HAeBe stars change systematically with stellar effective temperature; PAH in HAeBe disks are ionized. As part of a Spitzer archival project we are applying our spectral analysis methods to an even larger sample of HAeBe stars observed with the IRS and currently available in the Spitzer archive. Here we report preliminary results as we begin the larger study.

Measurements of mass accretion rates in Herbig Ae/Be stars

NASA Astrophysics Data System (ADS)

Donehew, Brian

Herbig Ae/Be stars(HAeBes) are young stellar objects of spectral class F2 through B0, with the central star often surrounded by a circumstellar disk of gas and dust. They are the higher mass analogs to T Tauri stars. The interaction between the star and the disk is not well understood, nor is the disk structure. The central star will often accrete mass from the disk, and the mass accretion rate is an important parameter for modeling the disk structure and evolution. The methods for measuring mass accretion rates of T Tauri stars are generally not applicable to HAeBe stars. As such, reliable measurements of mass accretion rates for HAeBes are rare. Garrison(1978) saw that the Balmer Discontinuity of HAeBes was veiled, and attributed this veiling to accretion luminosity. Building on Garrison(1978) and the work of Muzerolle et al. (2004), I determine the mass accretion rates and accretion luminosities of a large sample of HAeBe stars by measuring the veiling of the Balmer Discontinuity due to the accretion luminosity. Muzerolle et al. (1998) established a strong correlation between the accretion luminosity of T Tauri stars and the luminosity of Br gamma, and this correlation seems to extend to the evolutionary precursors to HAeBes, intermediate T Tauri stars, as well Calvet et al. (2004). I test this correlation for HAeBes and discover that it is valid for HAe stars but not for HBe stars. From examining the HAeBes of my sample from spectral range A3 to B7, there does not seem to be a particular spectral type at which the correlation fails. A few of the late HBe stars are consistent with the correlation, but most of the HBe stars have Br gamma luminosities much larger than what one would expect from the correlation. This suggests that there might be a significant stellar wind component to the Br gamma luminosity for many of the HBe stars. T Tauri stars accrete mass from their disks magnetospherically, in which the strong stellar field of the star truncates the disk at

Observations of Herbig Ae/Be Stars with Herschel/PACS: The Atomic and Molecular Contents of Their Protoplanetary Discs

NASA Technical Reports Server (NTRS)

Meeus, G.; Montesinos, B.; Mendigutia, I.; Kamp, I.; Thi, W. F.; Eiroa, C.; Grady, C. A.; Mathews, G.; Sandell, G.; Martin-Zaidi, C.;

A STUDY OF RO-VIBRATIONAL OH EMISSION FROM HERBIG Ae/Be STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brittain, Sean D.; Reynolds, Nickalas; Najita, Joan R.

2016-10-20

We present a study of ro-vibrational OH and CO emission from 21 disks around Herbig Ae/Be stars. We find that the OH and CO luminosities are proportional over a wide range of stellar ultraviolet luminosities. The OH and CO line profiles are also similar, indicating that they arise from roughly the same radial region of the disk. The CO and OH emission are both correlated with the far-ultraviolet luminosity of the stars, while the polycyclic aromatic hydrocarbon (PAH) luminosity is correlated with the longer wavelength ultraviolet luminosity of the stars. Although disk flaring affects the PAH luminosity, it is notmore » a factor in the luminosity of the OH and CO emission. These properties are consistent with models of UV-irradiated disk atmospheres. We also find that the transition disks in our sample, which have large optically thin inner regions, have lower OH and CO luminosities than non-transition disk sources with similar ultraviolet luminosities. This result, while tentative given the small sample size, is consistent with the interpretation that transition disks lack a gaseous disk close to the star.« less

New Light on Dark Energy

NASA Astrophysics Data System (ADS)

2008-01-01

Using ESO's Very Large Telescope Interferometer, astronomers have probed the inner parts of the disc of material surrounding a young stellar object, witnessing how it gains its mass before becoming an adult. ESO PR Photo 03/08 ESO PR Photo 03a/08 The disc around MWC 147 (Artist's Impression) The astronomers had a close look at the object known as MWC 147, lying about 2,600 light years away towards the constellation of Monoceros ('the Unicorn'). MWC 147 belongs to the family of Herbig Ae/Be objects. These have a few times the mass of our Sun and are still forming, increasing in mass by swallowing material present in a surrounding disc. MWC 147 is less than half a million years old. If one associated the middle-aged, 4.6 billion year old Sun with a person in his early forties, MWC 147 would be a 1-day-old baby [1]. The morphology of the inner environment of these young stars is however a matter of debate and knowledge of it is important to better understand how stars and their cortège of planets form. The astronomers Stefan Kraus, Thomas Preibisch, and Keiichi Ohnaka have used the four 8.2-m Unit Telescopes of ESO's Very Large Telescope to this purpose, combining the light from two or three telescopes with the MIDI and AMBER instruments. "With our VLTI/MIDI and VLTI/AMBER observations of MWC147, we combine, for the first time, near- and mid-infrared interferometric observations of a Herbig Ae/Be star, providing a measurement of the disc size over a wide wavelength range [2]," said Stefan Kraus, lead-author of the paper reporting the results. "Different wavelength regimes trace different temperatures, allowing us to probe the disc's geometry on the smaller scale, but also to constrain how the temperature changes with the distance from the star." The near-infrared observations probe hot material with temperatures of up to a few thousand degrees in the innermost disc regions, while the mid-infrared observations trace cooler dust further out in the disc. The

Ultraviolet continuum variability and visual flickering in the peculiar object MWC 560

NASA Technical Reports Server (NTRS)

Michalitsianos, A. G.; Perez, M.; Shore, S. N.; Maran, S. P.; Karovska, M.; Sonneborn, G.; Webb, J. R.; Barnes, Thomas G., III; Frueh, Marian L.; Oliversen, R. J.

1993-01-01

High-speed U-band photometry of the peculiar emission object MWC 560 obtained with the ground-based instrumentation, and V-band photometry obtained with the International Ultraviolet Explorer-Fine Error Sensor indicates irregular brightness variations are quasi-periodic. Multiple peaks of relative brightness power indicate statistically significant quasi periods existing in a range of 3-35 minutes, that are superposed on slower hourly varying components. We present a preliminary model that explains the minute and hourly time-scale variations in MWC 560 in terms of a velocity-shear instability that arises because a white dwarf magnetosphere impinges on an accretion disk. We also find evidence for Fe II multiplet pseudocontinuum absorption opacity in far-UV spectra of CH Cygni which is also present in MWC 560. Both CH Cyg and MWC 560 may be in an evolutionary stage that is characterized by strong UV continuum opacity which changes significantly during outburst, occurring before they permanently enter the symbiotic nebular emission phase.

Gas dynamics in the inner few AU around the Herbig B[e] star MWC297. Indications of a disk wind from kinematic modeling and velocity-resolved interferometric imaging

NASA Astrophysics Data System (ADS)

Hone, Edward; Kraus, Stefan; Kreplin, Alexander; Hofmann, Karl-Heinz; Weigelt, Gerd; Harries, Tim; Kluska, Jacques

2017-10-01

Aims: Circumstellar accretion disks and outflows play an important role in star formation. By studying the continuum and Brγ-emitting region of the Herbig B[e] star MWC297 with high-spectral and high-spatial resolution we aim to gain insight into the wind-launching mechanisms in young stars. Methods: We present near-infrared AMBER (R = 12 000) and CRIRES (R = 100 000) observations of the Herbig B[e] star MWC297 in the hydrogen Brγ-line. Using the VLTI unit telescopes, we obtained a uv-coverage suitable for aperture synthesis imaging. We interpret our velocity-resolved images as well as the derived two-dimensional photocenter displacement vectors, and fit kinematic models to our visibility and phase data in order to constrain the gas velocity field on sub-AU scales. Results: The measured continuum visibilities constrain the orientation of the near-infrared-emitting dust disk, where we determine that the disk major axis is oriented along a position angle of 99.6 ± 4.8°. The near-infrared continuum emission is 3.6 × more compact than the expected dust-sublimation radius, possibly indicating the presence of highly refractory dust grains or optically thick gas emission in the inner disk. Our velocity-resolved channel maps and moment maps reveal the motion of the Brγ-emitting gas in six velocity channels, marking the first time that kinematic effects in the sub-AU inner regions of a protoplanetary disk could be directly imaged. We find a rotation-dominated velocity field, where the blue- and red-shifted emissions are displaced along a position angle of 24° ± 3° and the approaching part of the disk is offset west of the star. The visibility drop in the line as well as the strong non-zero phase signals can be modeled reasonably well assuming a Keplerian velocity field, although this model is not able to explain the 3σ difference that we measure between the position angle of the line photocenters and the position angle of the dust disk. We find that the fit can be

Near-IR Spectroscopy of Herbig Ae/Be Companion Stars

NASA Astrophysics Data System (ADS)

Rodgers, B. M.; van der Bliek, N. S.; Brandvig, B.; Thomas, S.; Doppmann, G.; Bouvier, J.

2005-12-01

We present first results of a program to obtain near-infrared spectra of candidate companions to intermediate mass pre-main sequence Herbig Ae/Be (HAEBE) stars. Accurate spectral classification is critical to proper identification of the secondary star and interpretation of its spectral energy distribution. Spectra also allow analysis of emission lines and other stellar charcteristics such as veiling and rotation, to determine the companion's evolutionary status and help establish binarity. Of the first six objects observed with GNIRS on Gemini South (AS310 NW, HD76534, HD150193, HR5999, HD141569 and CO Ori), we find two B+B companion pairs, three early A primaries with T Tauri type secondaries (G, K and M type), and a peculiar F+F pair in which the secondary star is the primary emission star (respectively). If true binaries, three systems are similar spectral type pairs but with very different extinction and emission properties. The three late-type secondaries all exhibit significant near-infrared excess, but only weak emission lines. Other components of our project are an AO-fed near-infrared imaging survey of a large sample of HAEBE systems (N. S. van der Bliek et al. poster) and modeling of companion spectral energy distributions (B. Brandvig et al. poster). Together, these three complementary approaches will result in the most thorough accounting of multiple HAEBE systems to date. Our initial spectroscopy sample contains about 40 objects taken from the literature, roughly half from Bouvier and Corporon (2001). Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil

Spectroscopy, MOST photometry, and interferometry of MWC 314: is it an LBV or an interacting binary?

NASA Astrophysics Data System (ADS)

Richardson, Noel D.; Moffat, Anthony F. J.; Maltais-Tariant, Raphaël; Pablo, Herbert; Gies, Douglas R.; Saio, Hideyuki; St-Louis, Nicole; Schaefer, Gail; Miroshnichenko, Anatoly S.; Farrington, Chris; Aldoretta, Emily J.; Artigau, Étienne; Boyajian, Tabetha S.; Gordon, Kathryn; Jones, Jeremy; Matson, Rachel; McAlister, Harold A.; O'Brien, David; Raghavan, Deepak; Ramiaramanantsoa, Tahina; Ridgway, Stephen T.; Scott, Nic; Sturmann, Judit; Sturmann, Laszlo; Brummelaar, Theo ten; Thomas, Joshua D.; Turner, Nils; Vargas, Norm; Zharikov, Sergey; Matthews, Jaymie; Cameron, Chris; Guenther, David; Kuschnig, Rainer; Rowe, Jason; Rucinski, Slavek; Sasselov, Dimitar; Weiss, Werner

2016-01-01

MWC 314 is a bright candidate luminous blue variable (LBV) that resides in a fairly close binary system, with an orbital period of 60.753 ± 0.003 d. We observed MWC 314 with a combination of optical spectroscopy, broad-band ground- and space-based photometry, as well as with long baseline, near-infrared interferometry. We have revised the single-lined spectroscopic orbit and explored the photometric variability. The orbital light curve displays two minima each orbit that can be partially explained in terms of the tidal distortion of the primary that occurs around the time of periastron. The emission lines in the system are often double-peaked and stationary in their kinematics, indicative of a circumbinary disc. We find that the stellar wind or circumbinary disc is partially resolved in the K'-band with the longest baselines of the CHARA Array. From this analysis, we provide a simple, qualitative model in an attempt to explain the observations. From the assumption of Roche Lobe overflow and tidal synchronization at periastron, we estimate the component masses to be M1 ≈ 5 M⊙ and M2 ≈ 15 M⊙, which indicates a mass of the LBV that is extremely low. In addition to the orbital modulation, we discovered two pulsational modes with the MOST satellite. These modes are easily supported by a low-mass hydrogen-poor star, but cannot be easily supported by a star with the parameters of an LBV. The combination of these results provides evidence that the primary star was likely never a normal LBV, but rather is the product of binary interactions. As such, this system presents opportunities for studying mass-transfer and binary evolution with many observational techniques.

Line Identifications and Preliminary Synthesis of High-resolution Infrared Spectra of CP and Herbig Ae Stars

NASA Astrophysics Data System (ADS)

Cowley, Charles R.; Castelli, F.; Hubrig, S.; Wolff, B.; Elkin, V.

2012-01-01

We report on surveys of infrared spectra of chemically peculiar and Herbig Ae stars based on CRIRES (Kaufl, et al. SPIE, 5492, 1218 2004). We discuss the magnetic CP stars Gamma Equ and HD 154708, and multiple-phase observations of the Herbig Ae star HD 101412. The Be star HR 4537 and HgMn HR 6620 were also examined. The primary emphasis of the present work is on line identifications primarily in four regions, 1065-1091, 1084-1109,1550-1587, and 2276-2313nm (with order gaps). Observations were reduced with recipes available from the ESO CRIRES data reduction pipeline. Wavelength calibration is determined from daytime ThAr arc lamp exposures. Generally speaking, this is not rich in atomic lines. The strongest features are the Paschen line P6 (1093.81nm), and He I (108.30nm). The latter shows phase variations indicative of a more complex magnetic field than that of a pure dipole. No individual molecular lines were found in these early stars, though CO emission from circumstellar material is likely present in HR 4537 and HD 101412. We used atomic line lists from Kurucz's site (kurucz.harvard.edu) and VALD (http://vald.astro.univie.ac.at/ cf. Kupka et al. 1999, A&AS, 138, 119), supplemented by Outred (J. Phys. Chem. Ref. Data 7, 1, 1978). The following spectra were identified in Gamma Equ: C I, Si I, Ca I, Mg I, II, Cr I, Fe I, Sr II, and Ce III (1584.75nm). The Ap star spectra show broad Zeeman patterns compatible with published models and field strengths. Synthetic calculations used SYNTHE and SYNTHMAG (Piskunov N. E., 1999, in Astrophys. Space Sci. Library Vol. 243, Solar polarization. Kluwer, p 515). The γ Equ model is from Heiter et al. (2002, A&A, 392, 619). and the line list from VALD.

HIGH-RESOLUTION MID-INFRARED IMAGING OF THE CIRCUMSTELLAR DISKS OF HERBIG Ae/Be STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marinas, N.; Telesco, C. M.; Packham, C.

2011-08-20

We have imaged the circumstellar environments of 17 Herbig Ae/Be stars at 12 and 18 {mu}m using MICHELLE on Gemini North and T-ReCS on Gemini South. Our sample contained eight Group I sources, those having large rising near- to far-infrared (IR) fluxes, and nine Group II sources, those having more modest mid-IR fluxes relative to their near-IR flux (in the classification of Meeus et al.). We have resolved extended emission from all Group I sources in our target list. The majority of these sources have radially symmetric mid-IR emission extending from a radius of 10 AU to hundreds of AU.more » Only one of the nine Group II sources is resolved at the FWHM level, with another two Group II sources resolved at fainter levels. Models by Dullemond et al. explain the observed spectral energy distribution of Group II sources using self-shadowed cold disks. If this is the case for all the Group II sources, we do not expect to detect extended emission with this study, since the IR emission measured should arise from a region only a few AU in size, which is smaller than our resolution. The fact that we do resolve some of the Group II sources implies that their disks are not completely flat, and might represent an intermediate stage. We also find that none of the more massive (>3 M{sub sun}) Herbig Ae/Be stars in our sample belongs to Group I, which may point to a relationship between stellar mass and circumstellar dust evolution. Disks around more massive stars might evolve faster so that stars are surrounded by a more evolved flat disk by the time they become optically visible, or they might follow a different evolutionary path altogether.« less

Photometric and Polarimetric Activity of the Herbig Ae Star VX Cas

NASA Astrophysics Data System (ADS)

Shakhovskoi, D. N.; Rostopchina, A. N.; Grinin, V. P.; Minikulov, N. Kh.

2003-04-01

We present the results of our simultaneous photometric and polarimetric observations of the Herbig Ae/Be star VX Cas acquired in 1987 2001. The star belongs to the UX Ori subtype of young variable stars and exhibits a rather low level of photometric activity: only six Algol-like minima with amplitudes ΔV>1m were recorded in 15 years of observations. Two of these minima, in 1998 and 2001, were the deepest in the history of the star’s photometric studies, with V amplitudes of about 2m. In each case, the dimming was accompanied by an increase in the linear polarization in agreement with the law expected for variable circumstellar extinction. The highest V polarization was about 5%. Observations of VX Cas in the deep minima revealed a turnover of the color tracks, typical of stars of this type and due to an increased contribution from radiation scattered in the circumstellar disk. We separated the observed polarization of VX Cas into interstellar (P is) and intrinsic (P in) components. Their position angles differ by approximately 60°, with P is dominating in the bright state and P in dominating during the deep minima. The competition of these two polarization components leads to changes in both the degree and position angle of the polarization during the star’s brightness variations. Generally speaking, in terms of the behavior of the brightness, color indices, and linear polarization, VX Cas is similar to other UX Ori stars studied by us earlier. A number of episodes of photometric and polarimetric activity suggest that, in their motion along highly eccentric orbits, circumstellar gas and dust clouds can enter the close vicinity of the star (and be disrupted there).

New Observations of Candidate Herbig Ae/Be Stars in the LMC and SMC

NASA Astrophysics Data System (ADS)

Bjorkman, K. S.; Wisniewski, J. P.; Bjorkman, J. E.; Hesselbach, E. N.

2005-12-01

Based on analysis of the EROS microlensing data set, Lamers, Beaulieu, & de Wit (1999) and de Wit, Beaulieu, & Lamers (2002) identified 21 candidate Herbig Ae/Be (HAeBe) stars in the Large Magellanic Cloud (LMC). They based the selection of candidates on the irregular photometric variability exhibited by these stars, which bore some resemblance to the variability exhibited by known Galactic HAeBe stars. The candidate stars identified were designated as EROS LMC HAeBe Candidates, or ELHCs. A smaller number (7) of candidate stars identified in the SMC (Beaulieu et al. 2001; de Wit et al. 2003) were similarly designated ESHCs. Using the CTIO 0.9m telescope and imaging camera, we obtained B, V, R, and Hα photometry of 2 fields in the LMC encompassing 12 of the ELHCs. We used the CTIO 4m Blanco telescope with the Hydra multi-object spectrograph to obtain optical spectroscopy of all the ELHC stars as well as the ESHC stars. Further observations included JHK photometry of both the ELHC and ESHC fields using the CTIO 4m plus the ISPI infrared imager. We will discuss the results from our observations, and comment on the implications for the tentative identification of these stars as candidate HAeBe stars. We will also compare our results with the recent findings of de Wit et al. (2005). This work has been supported in part by NASA LTSA grant (KSB) NAG5-8054 and NASA GSRP Fellowship (JPW) NGT5-5069 to the University of Toledo. We thank the NOAO TAC for providing observing time for this project, and for providing travel support for JPW.

Observations of Herbig Ae/Be stars with Herschel/PACS. The atomic and molecular contents of their protoplanetary discs

NASA Astrophysics Data System (ADS)

Meeus, G.; Montesinos, B.; Mendigutía, I.; Kamp, I.; Thi, W. F.; Eiroa, C.; Grady, C. A.; Mathews, G.; Sandell, G.; Martin-Zaïdi, C.; Brittain, S.; Dent, W. R. F.; Howard, C.; Ménard, F.; Pinte, C.; Roberge, A.; Vandenbussche, B.; Williams, J. P.

2012-08-01

We observed a sample of 20 representative Herbig Ae/Be stars and 5 A-type debris discs with PACS onboard Herschel, as part of the GAS in Protoplanetary Systems (GASPS) project. The observations were done in spectroscopic mode, and cover the far-infrared lines of [O i], [C ii], CO, CH+, H2O, and OH. We have a [O i] 63 μm detection rate of 100% for the Herbig Ae/Be and 0% for the debris discs. The [O i] 145 μm line is only detected in 25% and CO J = 18-17 in 45% (and fewer cases for higher J transitions) of the Herbig Ae/Be stars, while for [C ii] 157 μm, we often find spatially variable background contamination. We show the first detection of water in a Herbig Ae disc, HD 163296, which has a settled disc. Hydroxyl is detected as well in this disc. First seen in HD 100546, CH+ emission is now detected for the second time in a Herbig Ae star, HD 97048. We report fluxes for each line and use the observations as line diagnostics of the gas properties. Furthermore, we look for correlations between the strength of the emission lines and either the stellar or disc parameters, such as stellar luminosity, ultraviolet and X-ray flux, accretion rate, polycyclic aromatic hydrocarbon (PAH) band strength, and flaring. We find that the stellar ultraviolet flux is the dominant excitation mechanism of [O i] 63 μm, with the highest line fluxes being found in objects with a large amount of flaring and among the largest PAH strengths. Neither the amount of accretion nor the X-ray luminosity has an influence on the line strength. We find correlations between the line flux of [O i] 63 μm and [O i] 145 μm, CO J = 18-17 and [O i] 6300 Å, and between the continuum flux at 63 μm and at 1.3 mm, while we find weak correlations between the line flux of [O i] 63 μm and the PAH luminosity, the line flux of CO J = 3-2, the continuum flux at 63 μm, the stellar effective temperature, and the Brγ luminosity. Finally, we use a combination of the[O i] 63 μm and 12CO J = 2-1 line fluxes to

40 CFR Table 1 to Subpart Fff of... - Municipal Waste Combustor Units (MWC Units) Excluded From Subpart FFF 1

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 9 2013-07-01 2013-07-01 false Municipal Waste Combustor Units (MWC... FOR DESIGNATED FACILITIES AND POLLUTANTS Federal Plan Requirements for Large Municipal Waste... Part 62—Municipal Waste Combustor Units (MWC Units) Excluded From Subpart FFF 1 State MWC units Alabama...

Near-Infrared Polarimetric Imaging of Disks around Young Intermediate-mass Stars in SEEDS

NASA Astrophysics Data System (ADS)

Fukagawa, Misato; Hashimoto, Jun; Grady, C. A.; Momose, Munetake; Wisniewski, J. P.; Okamoto, Yoshiko; Muto, Takayuki; Kusakabe, Nobuhiko; Bonnefoy, Mickael; Kotani, Takayuki; Maruta, Yayoi; Tamura, Motohide; Seeds/Hiciao/Ao188 Collaboration,

2013-07-01

We present our recent results to directly image circumstellar disks around Herbig Fe/Ae/Be stars in scattered light with Subaru. Observations of such young disks are critically important to understand how disks evolve possibly under the mutual interaction with new-born planets. One of the observational approaches is direct imaging in scattered light, and the progress in this field since PPV can be found in the ability to prove inner regions of disks. This improvement largely owes to the technique of polarization differential imaging (PDI) which provides higher contrast by extracting scattered light from the disk while suppressing unpolarized stellar light. Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) is the project dedicated to exoplanet hunting and study of circumstellar disks by direct imaging. Since its beginning in 2009, thirteen Herbig Fe/Ae/Be stars have been observed primarily in H band (1.6 micron). The PDI method has been employed with adaptive optics, enabling us to look into the inner region as close as 0.2 arcsec (˜30 AU) in radius with the typical angular resolution of 0.06 arcsec (˜8 AU). As a result, the SEEDS imagery has newly uncovered rich structures such as spiral arms, inner holes, and gaps for (pre-)transitional disks while suggested the variably illuminated disks for primordial systems. The highlight is the discovery of two spiral arms each for SAO 206462 and MWC 758. The spiral feature has been uniquely found toward Herbig Fe/Aes so far, which might be due to their warmer disks producing arms loosely wound and more easily detected. The observed morphology can be interpreted by the density-wave model, and those disks are implied to harbor Jupiter-mass companions as the exciting sources of the spiral structures according to these models.

A high-sensitivity survey of radio continuum emission from Herbig Ae/Be stars

NASA Technical Reports Server (NTRS)

Skinner, Stephen L.; Brown, Alexander; Stewart, Ron T.

1993-01-01

Results of a high-sensitivity VLA/Australia Telescope survey of radio continuum emission from the 57 Herbig Ae/Be stars and candidates in the 1984 catalog of Finkenzeller and Mundt are presented. Twelve stars were detected at the primary observing wavelength of 3.6 cm, on the basis that not less than 4 sigma radio sources lie within 1 arcsec of the optical positions. It is suggested that the radio emission is predominantly thermal and in many cases wind-related. The unusual eclipsing binary TY CrA is an exception and is classified as a nonthermal radio source on the basis of its decidedly negative spectral index (alpha = -1.2). A simple spherically symmetric free-fall accretion model is used to show that the predicted radio fluxes due to accretion at rates, estimated in the literature, of about 10 exp -6 to 10 exp -5 solar mass/yr are one to four orders of magnitude larger than observed.

Spectral Variability of the Herbig Ae/Be Star HD 37806

NASA Astrophysics Data System (ADS)

Pogodin, M. A.; Pavlovskiy, S. E.; Kozlova, O. V.; Beskrovnaya, N. G.; Alekseev, I. Yu.; Valyavin, G. G.

2018-03-01

Results are reported from a spectroscopic study of the Herbig Ae/Be star HD 37806 from 2009 through 2017 using high resolution spectrographs at the Crimean Astrophysical Observatory and the OAN SPM Observatory in Mexico. 72 spectra of this object near the Hα, Hβ, HeI 5876 and D NaI lines are analyzed. The following results were obtained: 1. The type of spectral profile of the Hα line can change from P Cyg III to double emission and vice versa over a time scale on the order of a month. 2. Narrow absorption components are observed in the profiles of the Hα and D NaI lines with radial velocities that vary over a characteristic time on the order of a day. 3. On some days, the profiles of the Hβ, HeI 5876, and D NaI lines show signs of accretion of matter to the star with a characteristic lifetime of a few days. A possible interpretation of these phenomena was considered. The transformation of the Hα profile may be related to a change in the outer latitudinal width of the boundary of the wind zone. The narrow variable absorption lines may be caused by the rotation of local azimuthal inhomogeneities in the wind zone owing to the interaction of the disk with the star's magnetosphere in a propeller regime. Several current theoretical papers that predict the formation of similar inhomogeneous wind structures were examined. It is suggested that the episodes with signs of accretion in the spectral line profiles cannot be a consequence of the modulation of these profiles by the star's rotation but are more likely caused by sudden, brief changes in the accretion rate. These spectral observations of HD 37806 should be continued in a search for cyclical variability in the spectral parameters in order to identify direct signs of magnetospheric accretion and detect possible binary behavior in this object.

The evidence for clumpy accretion in the Herbig Ae star HR 5999

NASA Technical Reports Server (NTRS)

Perez, M. R.; Grady, C. A.; The, P. S.

1993-01-01

Analysis of IUE high- and low-dispersion spectra of the young Herbig Ae star HR 5999 (HD 144668) covering 1978-1992 revealed dramatic changes in the Mg II h and k (2795.5, 2802.7 A) emission profiles, changes in the column density and distribution in radial velocity of accreting gas, and flux in the Ly(alpha), O I, and C IV emission lines, which are correlated with the UV excess luminosity. Variability in the spectral type inferred from the UV spectral energy distribution, ranging from A5 IV-III in high state to A7 III in the low state, was also observed. The trend of earlier inferred spectral type with decreasing wavelength and with increasing UV continuum flux has previously been noted as a signature of accretion disks in lower mass pre-main sequence stars (PMS) and in systems undergoing FU Orionis-type outbursts. Our data represent the first detection of similar phenomena in an intermediate mass (M greater than or equal to 2 solar mass) PMS star. Recent IUE spectra show gas accreting toward the star with velocities as high as plus 300 km/s, much as is seen toward beta Pic, and suggest that we also view this system through the debris disk. The absence of UV lines with the rotational broadening expected given the optical data (A7 IV, V sini=180 plus or minus 20 km/s for this system) also suggests that most of the UV light originates in the disk, even in the low continuum state. The dramatic variability in the column density of accreting gas, is consistent with clumpy accretion, such as has been observed toward beta Pic, is a hallmark of accretion onto young stars, and is not restricted to the clearing phase, since detectable amounts of accretion are present for stars with 0.5 Myr less than t(sub age) less than 2.8 Myr. The implications for models of beta Pic and similar systems are briefly discussed.

Medium-resolution échelle spectroscopy of the Red Square Nebula, MWC 922

NASA Astrophysics Data System (ADS)

Wehres, N.; Ochsendorf, B. B.; Tielens, A. G. G. M.; Cox, N. L. J.; Kaper, L.; Bally, J.; Snow, T. P.

2017-05-01

Context. Medium-resolution échelle spectra of the Red Square Nebula surrounding the star MWC 922 are presented. The spectra have been obtained in 2010 and 2012 using the X-shooter spectrograph mounted on the Very Large Telescope (VLT) in Paranal, Chile. The spectrum covers a wavelength range between 300 nm-2.5 μm and shows that the nebula is rich in emission lines. Aims: We aim to identify the emission lines and use them as a tool to determine the physical and chemical characteristics of the nebula. The emission lines are also used to put constraints on the structure of the nebula and on the nature of the central stars. Methods: We analyzed and identified emission lines that indicated that the Red Square Nebula consists of a low density bipolar outflow, eminent in the broad emission component seen in [Fe II], as well as in P Cygni line profiles indicative of fast outflowing material. The narrow component in the [Fe II] lines is most likely formed in the photosphere of a surrounding disk. Some of the emission lines show a pronounced double peaked profile, such as Ca II, indicating an accretion disk in Keplerian rotation around the central star. [O I] emission lines are formed in the neutral atomic zone separating the ionized disk photosphere from the molecular gas in the interior of the disk, which is prominent in molecular CO emission in the near-IR. [N II] and [S II] emission clearly originates in a low density but fairly hot (7 000-10 000 K) nebular environment. H I recombination lines trace the extended nebula as well as the photosphere of the disk. Results: These findings put constraints on the evolution of the central objects in MWC 922. The Red Square shows strong similarities to the Red Rectangle Nebula, both in morphology and in its mid-IR spectroscopic characteristics. As for the Red Rectangle, the observed morphology of the nebula reflects mass-loss in a binary system. Specifically, we attribute the biconical morphology and the associated rung

A Study of Rovibrational H2O, OH, and CO emission from the Herbig Ae/Be star HD 250550

NASA Astrophysics Data System (ADS)

Leiendecker, Harrison; Brittain, Sean; Jensen, Stanley; Najita, Joan R.; Carr, John S.

2018-01-01

We present high-resolution spectroscopy (R∼75,000) of the Herbig Ae/Be star HD 250550. The L-band spectroscopy was obtained with the infrared echelle spectrograph (iSHELL) from The NASA Infrared Telescope Facility. We will describe the performance of the instrument and compare the CO and OH emission and upper limit on H2O emission to other Herbig Ae/Be stars. Specifically, L-band observationsof the ro-vibrational OH emission from the disk surrounding HD 250550 is compared to emission properties of the sources studied by Brittain et al. (2016). The OH 2Π3/2 P4.5 (1+,1-) doublet and the P5.5 (1+) line are spectrally resolved and have the same spectral profile as the CO ro-vibrational lines indicating that they arise from the same emitting region of the disk. The relative fluxes of the ro-vibrational lines from CO indicate that the rotational temperature of the gas is 1060 ± 115 K. The relative fluxes of the ro-vibrational lines from OH are consistent with this temperature.

Interpreting the spectral behavior of MWC 314

NASA Astrophysics Data System (ADS)

Frasca, A.; Miroshnichenko, A. S.; Rossi, C.; Friedjung, M.; Marilli, E.; Muratorio, G.; Busà, I.

2016-01-01

Context. MWC 314 is one of the most luminous stars in the Milky Way. Its fundamental parameters are similar to those of luminous blue variables (LBVs), although no large photometric variations have been recorded. Moreover, it shows no evidence of either a dust shell or a relevant spectral variability. Aims: The main purpose of this work is to clarify the origin of the radial velocity and line profile variations exhibited by absorption and emission lines. Methods: We analyzed the radial velocity (RV) variations displayed by the absorption lines from the star's atmosphere using high-resolution optical spectra and fitting the RV curve with an eccentric orbit model. We also studied the RV and profile variations of some permitted and forbidden emission lines of metallic ions with a simple geometric model. The behavior of the Balmer and He I lines has also been investigated. Results: Fourier analysis applied to the RV of the absorption lines clearly shows a 60-day periodicity. A dense coverage of the RV curve allowed us to derive accurate orbital parameters. The RV of the Fe II emission lines varies in the same way, but with a smaller amplitude. Additionally, the intensity ratio of the blue/red peaks of these emission lines correlates with the RV variations. The first three members of the Balmer series as well as [N II] lines display a nearly constant RV and no profile variations in phase with the orbital motion instead. The He I λ5876 Å line shows a strongly variable profile with broad and blue-shifted absorption components that reach velocities of ≤-1000 km s-1 in some specific orbital phases. Conclusions: Our data and analysis provide strong evidence that the object is a binary system composed of a supergiant B[e] star and an undetected companion. The emission lines with a non-variable RV could originate in a circumbinary region. For the Fe II emission lines, we propose a simple geometrical two-component model where a compact source of Fe II emission, moving

Undergraduate Observations of Separation and Position Angle of Double Stars ARY 6 AD and ARY 6 AE at Manzanita Observatory

NASA Astrophysics Data System (ADS)

Hoffert, Michael J.; Weise, Eric; Clow, Jenna; Hirzel, Jacquelyn; Leeder, Brett; Molyneux, Scott; Scutti, Nicholas; Spartalis, Sarah; Tokuhara, Corey

2014-05-01

Six beginning astronomy students, part of an undergraduate stellar astronomy course, one advanced undergraduate student assistant, and a professor measured the position angles and separations of Washington Double Stars (WDS) 05460 + 2119 (also known as ARY 6 AD and ARY 6 AE). The measurements were made at the Manzanita Observatory (116° 20'42" W, 32° 44' 5" N) of the Tierra Astronomical Institute on 10 Blackwood Rd. in Boulevard, California (www.youtube.com/watch?v=BHVdcMGBGDU), at an elevation of 4,500 ft. A Celestron 11" HD Edge telescope was used to measure the position angles and separations of ARY 6 AD and ARY 6 AE. The averages of our measurements are as follows: separation AD: trial 1 124.1 arcseconds and trial 2 124.5 arcseconds. The average of separation for AE: trial 1 73.3 arcseconds and trial 2 73.8 arcseconds. The averages of position angle for AD: trial 1 159.9 degrees and trial 2 161.3 degrees. The averages of position angle for AE: trial 1 232.6 degrees and trial 2 233.7 degrees.

NuSTAR AND SWIFT Observations of the Fast Rotating Magnetized White Dwarf AE Aquarii

NASA Technical Reports Server (NTRS)

Kitaguchi, Takao; An, Hongjun; Beloborodov, Andrei M.; Gotthelf, Eric V.; Hayashi, Takayuki; Kaspi, Victoria M.; Rana, Vikram R.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.;

NuStar and Swift Observations of the Fast Rotating Magnetized White Dwarf AE Aquarii

NASA Technical Reports Server (NTRS)

Kitaguchi, Takao; An, Hongjun; Beloborodov, Andrei M.; Gotthelf, Eric V.; Hayashi, Takayuki; Kaspi, Victoria M.; Rana, Vikram R.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.;

Observational aspects of Herbig Ae/Be stars and of candidate young A/B stars

NASA Astrophysics Data System (ADS)

de Winter, Dolf

1996-06-01

The thesis consists of several studies on candidate young stars of which most material is published or in press and which can be divided into three parts roughly. Part A is about Herbig Ae/Be stars. A complete review of the observational properties of HAeBes is given in Chapter A1 together with a renewed up-to-date catalogue of HAeBes and HAeBe candidates. As an example of the selection of HAeBes from candidate stars, the observational properties of three candidates is discussed in Chapter A2. They are in particular interesting as they are relatively bright with respect to other HAeBes candidates. An advantage of bright HAeBes is that high resolution spectroscopy can be obtained. For two well know HAeBe objects with a favourable oriented disk, UX and BF Ori, a high resolution spectroscopy monitoring programme is presented in Chapters A3 and A4. First results presented indicate that the disk material of UX Ori is accreting in the form of comet-like bodies. Such pioneering results are also found for BF Ori but more details of the cometaries are given. As discussed in Chapter A1, the IR-excess is one of the fundamental discriminators for the selection of HAeBe candidates. A good understanding of the origin of the IR-excess of HAeBe candidates is necessary to study the disk material that ultimately could produce (proto-)planetary systems. Chapter A5 discusses the amount of IR-excess of HAeBe candidates and ideas about the probable origin. In Part B objects are discussed which were originally selected as HAeBe candidates, but for which a more detailed analysis of the observational characteristics show that they are probably more evolved. This group contains very interesting objects as is shown in Chapters B1, B2 and B3, in which the discovery of a new galactic Luminous Blue Variable (LBV) is reported, WRA 751. A well known B[e] star is HD 45677. The B[e]-group was collected to consist of evolved objects with masses less than those of LBVs and comparable with B[e] stars

Multi-epoch Detections of Water Ice Absorption in Edge-on Disks around Herbig Ae Stars: PDS 144N and PDS 453

NASA Astrophysics Data System (ADS)

Terada, Hiroshi; Tokunaga, Alan T.

2017-01-01

We report the multi-epoch detections of water ice in 2.8-4.2 μ {{m}} spectra of two Herbig Ae stars, PDS 144N (A2 IVe) and PDS 453 (F2 Ve), which have an edge-on circumstellar disk. The detected water ice absorption is found to originate from their protoplanetary disks. The spectra show a relatively shallow absorption of water ice of around 3.1 μ {{m}} for both objects. The optical depths of the water ice absorption are ˜0.1 and ˜0.2 for PDS 144N and PDS 453, respectively. Compared to the water ice previously detected in low-mass young stellar objects with an edge-on disk with a similar inclination angle, these optical depths are significantly lower. It suggests that stronger UV radiation from the central stars effectively decreases the water ice abundance around the Herbig Ae stars through photodesorption. The water ice absorption in PDS 453 shows a possible variation of the feature among the six observing epochs. This variation could be due to a change of absorption materials passing through our line of sight to the central star. The overall profile of the water ice absorption in PDS 453 is quite similar to the absorption previously reported in the edge-on disk object d216-0939, and this unique profile may be seen only at a high inclination angle in the range of 76°-80°.

AE AURIGAE: FIRST DETECTION OF NON-THERMAL X-RAY EMISSION FROM A BOW SHOCK PRODUCED BY A RUNAWAY STAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopez-Santiago, J.; Pereira, V.; De Castro, E.

2012-09-20

Runaway stars produce shocks when passing through interstellar medium at supersonic velocities. Bow shocks have been detected in the mid-infrared for several high-mass runaway stars and in radio waves for one star. Theoretical models predict the production of high-energy photons by non-thermal radiative processes in a number sufficiently large to be detected in X-rays. To date, no stellar bow shock has been detected at such energies. We present the first detection of X-ray emission from a bow shock produced by a runaway star. The star is AE Aur, which was likely expelled from its birthplace due to the encounter ofmore » two massive binary systems and now is passing through the dense nebula IC 405. The X-ray emission from the bow shock is detected at 30'' northeast of the star, coinciding with an enhancement in the density of the nebula. From the analysis of the observed X-ray spectrum of the source and our theoretical emission model, we confirm that the X-ray emission is produced mainly by inverse Compton upscattering of infrared photons from dust in the shock front.« less

40 CFR Table 1 to Subpart Fff of... - Municipal Waste Combustor Units (MWC Units) Excluded From Subpart FFF 1

Code of Federal Regulations, 2012 CFR

2012-07-01

... municipal solid waste at the following MWC sites: (a) Foster Wheeler Charleston Resource Recovery Facility... 40 Protection of Environment 9 2012-07-01 2012-07-01 false Municipal Waste Combustor Units (MWC... FOR DESIGNATED FACILITIES AND POLLUTANTS Federal Plan Requirements for Large Municipal Waste...

40 CFR Table 1 to Subpart Fff of... - Municipal Waste Combustor Units (MWC Units) Excluded From Subpart FFF 1

Code of Federal Regulations, 2014 CFR

2014-07-01

... municipal solid waste at the following MWC sites: (a) Foster Wheeler Charleston Resource Recovery Facility... 40 Protection of Environment 9 2014-07-01 2014-07-01 false Municipal Waste Combustor Units (MWC... FOR DESIGNATED FACILITIES AND POLLUTANTS Federal Plan Requirements for Large Municipal Waste...

Detection of Polarized Infrared Emission by Polycyclic Aromatic Hydrocarbons in the MWC 1080 Nebula

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Han; Telesco, Charles M.; Pantin, Eric

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in astrophysical environments, as revealed by their pronounced emission features at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 μ m commonly ascribed to the C–H and C–C vibrational modes. Although these features have long been predicted to be polarized, previous searches for PAH polarization led to null or, at best, tentative detections. Here we report the definite detection of polarized PAH emission at 11.3 μ m in the nebula associated with the Herbig Be star MWC 1080. We measure a polarization degree of 1.9% ± 0.2%, which is unexpectedly high compared to models. Thismore » poses a challenge in the current understanding of the alignment of PAHs, which is required to polarize the PAH emission but thought to be substantially suppressed. PAH alignment with a magnetic field via a resonance paramagnetic relaxation process may account for such a high level of polarization.« less

Detection of Polarized Infrared Emission by Polycyclic Aromatic Hydrocarbons in the MWC 1080 Nebula

NASA Astrophysics Data System (ADS)

Zhang, Han; Telesco, Charles M.; Hoang, Thiem; Li, Aigen; Pantin, Eric; Wright, Christopher M.; Li, Dan; Barnes, Peter

2017-07-01

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in astrophysical environments, as revealed by their pronounced emission features at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 μm commonly ascribed to the C-H and C-C vibrational modes. Although these features have long been predicted to be polarized, previous searches for PAH polarization led to null or, at best, tentative detections. Here we report the definite detection of polarized PAH emission at 11.3 μm in the nebula associated with the Herbig Be star MWC 1080. We measure a polarization degree of 1.9% ± 0.2%, which is unexpectedly high compared to models. This poses a challenge in the current understanding of the alignment of PAHs, which is required to polarize the PAH emission but thought to be substantially suppressed. PAH alignment with a magnetic field via a resonance paramagnetic relaxation process may account for such a high level of polarization.

Effect of Photodesorption on the Snow Lines at the Surface of Optically Thick Circumstellar Disks around Herbig Ae/Be Stars

NASA Astrophysics Data System (ADS)

Oka, Akinori; Inoue, Akio K.; Nakamoto, Taishi; Honda, Mitsuhiko

2012-03-01

We investigate the effect of photodesorption on the snow line position at the surface of a protoplanetary disk around a Herbig Ae/Be star, motivated by the detection of water ice particles at the surface of the disk around HD142527 by Honda et al. For this aim, we obtain the density and temperature structure in the disk with a 1+1D radiative transfer and determine the distribution of water ice particles in the disk by the balance between condensation, sublimation, and photodesorption. We find that photodesorption induced by far-ultraviolet radiation from the central star depresses the ice-condensation front toward the mid-plane and pushes the surface snow line significantly outward when the stellar effective temperature exceeds a certain critical value. This critical effective temperature depends on the stellar luminosity and mass, the water abundance in the disk, and the yield of photodesorption. We present an approximate analytic formula for the critical temperature. We separate Herbig Ae/Be stars into two groups on the HR diagram according to the critical temperature: one is the disks where photodesorption is effective and from which we may not find ice particles at the surface, and the other is the disks where photodesorption is not effective. We estimate the snow line position at the surface of the disk around HD142527 to be 100-300 AU, which is consistent with the water ice detection at >140 AU in the disk. All the results depend on the dust grain size in a complex way, and this point requires more work in the future.

A Survey of CH3CN and HC3N in Protoplanetary Disks

NASA Astrophysics Data System (ADS)

Bergner, Jennifer B.; Guzmán, Viviana G.; Öberg, Karin I.; Loomis, Ryan A.; Pegues, Jamila

2018-04-01

The organic content of protoplanetary disks sets the initial compositions of planets and comets, thereby influencing subsequent chemistry that is possible in nascent planetary systems. We present observations of the complex nitrile-bearing species CH3CN and HC3N toward the disks around the T Tauri stars AS 209, IM Lup, LkCa 15, and V4046 Sgr as well as the Herbig Ae stars MWC 480 and HD 163296. HC3N is detected toward all disks except IM Lup, and CH3CN is detected toward V4046 Sgr, MWC 480, and HD 163296. Rotational temperatures derived for disks with multiple detected lines range from 29 to 73 K, indicating emission from the temperate molecular layer of the disk. V4046 Sgr and MWC 480 radial abundance profiles are constrained using a parametric model; the gas-phase CH3CN and HC3N abundances with respect to HCN are a few to tens of percent in the inner 100 au of the disk, signifying a rich nitrile chemistry at planet- and comet-forming disk radii. We find consistent relative abundances of CH3CN, HC3N, and HCN between our disk sample, protostellar envelopes, and solar system comets; this is suggestive of a robust nitrile chemistry with similar outcomes under a wide range of physical conditions.

Determinations of the {sup 12}C/{sup 13}C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harrison, Thomas E.; Marra, Rachel E., E-mail: tharriso@nmsu.edu, E-mail: rmarra@nmsu.edu

We present new moderate-resolution near-infrared spectroscopy of three CVs obtained using GNIRS on Gemini-North. These spectra covered three {sup 13}CO bandheads found in the K -band, allowing us to derive the isotopic abundance ratios for carbon. We find small {sup 12}C/{sup 13}C ratios for all three donor stars. In addition, these three objects show carbon deficits, with AE Aqr being the most extreme ([C/Fe] = −1.4). This result confirms the conjecture that the donor stars in some long-period CVs have undergone considerable nuclear evolution prior to becoming semi-contact binaries. In addition to the results for carbon, we find that themore » abundance of sodium is enhanced in these three objects, and the secondary stars in both RU Peg and SS Cyg suffer magnesium deficits. Explaining such anomalies appears to require higher mass progenitors than commonly assumed for the donor stars of CVs.« less

Variability of Disk Emission in Pre-main-sequence and Related Stars. IV. Investigating the Structural Changes in the Inner Disk Region of MWC 480

NASA Astrophysics Data System (ADS)

Fernandes, Rachel B.; Long, Zachary C.; Pikhartova, Monika; Sitko, Michael L.; Grady, Carol A.; Russell, Ray W.; Luria, David M.; Tyler, Dakotah B.; Bayyari, Ammar; Danchi, William; Wisniewski, John P.

2018-04-01

We present five epochs of near-IR observations of the protoplanetary disk around MWC 480 (HD 31648) obtained with the SpeX spectrograph on NASA’s Infrared Telescope Facility between 2007 and 2013, inclusive. Using the measured line fluxes in the Pa β and Br γ lines, we found the mass accretion rates to be (1.26–2.30) × 10‑7 M ⊙ yr‑1 and (1.4–2.01) × 10‑7 M ⊙ yr‑1, respectively, but which varied by more than 50% from epoch to epoch. The spectral energy distribution reveals a variability of about 30% between 1.5 and 10 μm during this same period of time. We investigated the variability using of the continuum emission of the disk in using the Monte-Carlo Radiative Transfer Code HOCHUNK3D. We find that varying the height of the inner rim successfully produces a change in the NIR flux but lowers the far-IR emission to levels below all measured fluxes. Because the star exhibits bipolar flows, we utilized a structure that simulates an inner disk wind to model the variability in the near-IR, without producing flux levels in the far-IR that are inconsistent with existing data. For this object, variable near-IR emission due to such an outflow is more consistent with the data than changing the scale height of the inner rim of the disk.

Spectroastrometric Study of Ro-vibrational CO Emission from the Herbig Ae Star HD 179218 with ISHELL on the NASA Infrared Telescope Facility

NASA Astrophysics Data System (ADS)

Brittain, Sean D.; Carr, John S.; Najita, Joan R.

2018-07-01

We present analysis of commissioning M-band data acquired with the infrared echelle spectrograph (iSHELL) on NASA’s Infrared Telescope Facility. In this paper we describe the delivered performance of the instrument for these M-band observations and the data reduction process. The feasibility of using iSHELL for spectro-astrometry is tested on the Herbig Ae/Be star HD 179218 and we show that sub-milliarcsecond fidelity is achievable..

Undergraduate Observations of Separation and Position Angle of Double Stars WDS J05460+2119AB (ARY 6AD and ARY 6 AE) at Manzanita Observatory (Abstract)

NASA Astrophysics Data System (ADS)

HOffert, M. J.; Weise, E.; Clow, J.; Hirzel, J.; Leeder, B.; Molyneux, S.; Scutti, N.; Spartalis, S.; Takuhara, C.

2014-12-01

(Abstract only) Six beginning astronomy students, part of an undergraduate stellar astronomy course, one advanced undergraduate student assistant, and a professor measured the position angles and separations of Washington Double Stars (WDS) J05460+2119 (= WDS J05460+2119AB; also known as ARY 6 AD and ARY 6 AE). The measurements were made at the Manzanita Observatory (116º 20' 42" W, 32º 44' 5" N) of the Tierra Astronomical Institute on 10 Blackwood Road in Boulevard, California (www.youtube.com/watch?v=BHVdeMGBGDU), at an elevation of 4,500 ft. A Celestron 11-inch HD Edge telescope was used to measure the position angles and separations of ARY 6 AD and ARY 6 AE. The averages of our measurements are as follows: separation AD: trial 1 124.1 arcseconds and trial 2 124.5 arcseconds; separation AE: trial 1 73.3 arcseconds and trial 2 73.8 arcseconds. The averages of positon angle for AD: trial 1 159.9 degrees and trial 2 161.3 degrees, for AE: trial 1 232.6 degrees and trial 2 233.7 degrees.

THE IMPACT OF PARTICULATE EMISSIONS CONTROL ON THE CONTROL OF OTHER MWC AIR EMISSIONS

EPA Science Inventory

On December 20, 1989, the Environmental Protection Agency (EPA) proposed revised new source performance standards for new municipal waste combustion (MWC) units and guidelines for existing sources. The proposed national regulations require tighter particulate matter control and a...

AN IONIZED OUTFLOW FROM AB AUR, A HERBIG AE STAR WITH A TRANSITIONAL DISK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodríguez, Luis F.; Zapata, Luis A.; Ortiz-León, Gisela N.

AB Aur is a Herbig Ae star with a transitional disk. Transitional disks present substantial dust clearing in their inner regions, most probably because of the formation of one or more planets, although other explanations are still viable. In transitional objects, accretion is found to be about an order of magnitude smaller than in classical full disks. Since accretion is believed to be correlated with outflow activity, centimeter free-free jets are expected to be present in association with these systems, at weaker levels than in classical protoplanetary (full) systems. We present new observations of the centimeter radio emission associated withmore » the inner regions of AB Aur and conclude that the morphology, orientation, spectral index, and lack of temporal variability of the centimeter source imply the presence of a collimated, ionized outflow. The radio luminosity of this radio jet is, however, about 20 times smaller than that expected for a classical system of similar bolometric luminosity. We conclude that centimeter continuum emission is present in association with stars with transitional disks, but at levels than are becoming detectable only with the upgraded radio arrays. On the other hand, assuming that the jet velocity is 300 km s{sup –1}, we find that the ratio of mass loss rate to accretion rate in AB Aur is ∼0.1, similar to that found for less evolved systems.« less

Determinations of the 12C/13C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi

NASA Astrophysics Data System (ADS)

Harrison, Thomas E.; Marra, Rachel E.

2017-07-01

We present new moderate-resolution near-infrared spectroscopy of three CVs obtained using GNIRS on Gemini-North. These spectra covered three 13CO bandheads found in the K-band, allowing us to derive the isotopic abundance ratios for carbon. We find small 12C/13C ratios for all three donor stars. In addition, these three objects show carbon deficits, with AE Aqr being the most extreme ([C/Fe] = -1.4). This result confirms the conjecture that the donor stars in some long-period CVs have undergone considerable nuclear evolution prior to becoming semi-contact binaries. In addition to the results for carbon, we find that the abundance of sodium is enhanced in these three objects, and the secondary stars in both RU Peg and SS Cyg suffer magnesium deficits. Explaining such anomalies appears to require higher mass progenitors than commonly assumed for the donor stars of CVs. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), and Ministério da Ciência, Tecnologia e Inovação (Brazil).

Revealing the sub-AU asymmetries of the inner dust rim in the disk around the Herbig Ae star R Coronae Austrinae

NASA Astrophysics Data System (ADS)

Kraus, S.; Hofmann, K.-H.; Malbet, F.; Meilland, A.; Natta, A.; Schertl, D.; Stee, P.; Weigelt, G.

2009-12-01

Context: Unveiling the structure of the disks around intermediate-mass pre-main-sequence stars (Herbig Ae/Be stars) is essential for our understanding of the star and planet formation process. In particular, models predict that in the innermost AU around the star, the dust disk forms a “puffed-up” inner rim, which should result in a strongly asymmetric brightness distribution for disks seen under intermediate inclination. Aims: Our aim is to constrain the sub-AU geometry of the inner disk around the Herbig Ae star R CrA and search for the predicted asymmetries. Methods: Using the VLTI/AMBER long-baseline interferometer, we obtained 24 near-infrared (H- and K-band) spectro-interferometric observations on R CrA. Observing with three telescopes in a linear array configuration, each data set samples three equally spaced points in the visibility function, providing direct information about the radial intensity profile. In addition, the observations cover a wide position angle range (~97°), also probing the position angle dependence of the source brightness distribution. Results: In the derived visibility function, we detect the signatures of an extended (Gaussian FWHM ~ 25 mas) and a compact component (Gaussian FWHM ~ 5.8 mas), with the compact component contributing about two-thirds of the total flux (both in H- and K-band). The brightness distribution is highly asymmetric, as indicated by the strong closure phases (up to ~40°) and the detected position angle dependence of the visibilities and closure phases. To interpret these asymmetries, we employ various geometric as well as physical models, including a binary model, a skewed ring model, and a puffed-up inner rim model with a vertical or curved rim shape. For the binary and vertical rim model, no acceptable fits could be obtained. On the other hand, the skewed ring model and the curved puffed-up inner rim model allow us to simultaneously reproduce the measured visibilities and closure phases. From these

High-resolution 25 μm Imaging of the Disks around Herbig Ae/Be Stars

NASA Astrophysics Data System (ADS)

Honda, M.; Maaskant, K.; Okamoto, Y. K.; Kataza, H.; Yamashita, T.; Miyata, T.; Sako, S.; Fujiyoshi, T.; Sakon, I.; Fujiwara, H.; Kamizuka, T.; Mulders, G. D.; Lopez-Rodriguez, E.; Packham, C.; Onaka, T.

2015-05-01

We imaged circumstellar disks around 22 Herbig Ae/Be stars at 25 μm using Subaru/COMICS and Gemini/T-ReCS. Our sample consists of an equal number of objects from each of the two categories defined by Meeus et al.; 11 group I (flaring disk) and II (flat disk) sources. We find that group I sources tend to show more extended emission than group II sources. Previous studies have shown that the continuous disk is difficult to resolve with 8 m class telescopes in the Q band due to the strong emission from the unresolved innermost region of the disk. This indicates that the resolved Q-band sources require a hole or gap in the disk material distribution to suppress the contribution from the innermost region of the disk. As many group I sources are resolved at 25 μm, we suggest that many, but not all, group I Herbig Ae/Be disks have a hole or gap and are (pre-)transitional disks. On the other hand, the unresolved nature of many group II sources at 25 μm supports the idea that group II disks have a continuous flat disk geometry. It has been inferred that group I disks may evolve into group II through the settling of dust grains into the mid-plane of the protoplanetary disk. However, considering the growing evidence for the presence of a hole or gap in the disk of group I sources, such an evolutionary scenario is unlikely. The difference between groups I and II may reflect different evolutionary pathways of protoplanetary disks. Based on data collected at the Subaru Telescope, via the time exchange program between Subaru and the Gemini Observatory. The Subaru Telescope is operated by the National Astronomical Observatory of Japan.

Modeling of the hydrogen maser disk in MWC 349

NASA Astrophysics Data System (ADS)

Ponomarev, Victor O.; Smith, Howard A.; Strelnitski, Vladimir S.

1994-04-01

Maser amplification in a Keplerian circumstellar disk seen edge on-the idea put forward by Gordon (1992), Martin-Pintado, & Serabyn (1992), and Thum, Martin-Pintado, & Bachiller (1992) to explain the millimeter hydrogen recombination lines in MWC 349-is further justified and developed here. The double-peaked (vs. possible triple-peaked) form of the observed spectra is explained by the reduced emission from the inner portion of the disk, the portion responsible for the central ('zero velocity') component of a triple-peaked spectrum. Radial gradient of electron density and/or free-free absorption within the disk are identified as the probable causes of this central 'hole' in the disk and of its opacity. We calculate a set of synthetic maser spectra radiated by a homogeneous Keplerian ring seen edge-on and compare them to the H30-alpha observations of Thum et al., averaged over about 1000 days. We used a simple graphical procedure to solve an inverse problem and deduced the probable values of some basic disk and maser parameters. We find that the maser is essentially unsaturated, and that the most probable values of electron temperature. Doppler width of the microturbulence, and electron density, all averaged along the amplification path are, correspondingly, Te less than or equal to 11,000 K, Vmicro less than or equal to 14 km/s, ne approx. = (3 +/- 2) x 107/cu cm. The model shows that radiation at every frequency within the spectrum arises in a monochromatic 'hot spot.' The maximum optical depth within the 'hot spot' producing radiation at the spectral peak maximum is taumax approx. = 6 +/- 1; the effective width of the masing ring is approx. = 0.4-0.7 times its outer diameter; the size of the 'hot spot' responsible for the radiation at the spectral peak frequency is approx. = 0.2-0.3 times the distance between the two 'hot spots' corresponding to two peaks. An important derivation of our model is the dynamical mass of the central star, M* approx. = 26 solar masses

Polycyclic Aromatic Hydrocarbons in Protoplanetary Disks around Herbig Ae/Be and T Tauri Stars

NASA Astrophysics Data System (ADS)

Seok, Ji Yeon; Li, Aigen

2017-02-01

A distinct set of broad emission features at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 μm, is often detected in protoplanetary disks (PPDs). These features are commonly attributed to polycyclic aromatic hydrocarbons (PAHs). We model these emission features in the infrared spectra of 69 PPDs around 14 T Tauri and 55 Herbig Ae/Be stars in terms of astronomical PAHs. For each PPD, we derive the size distribution and the charge state of the PAHs. We then examine the correlations of the PAH properties (I.e., sizes and ionization fractions) with the stellar properties (e.g., stellar effective temperature, luminosity, and mass). We find that the characteristic size of the PAHs tends to correlate with the stellar effective temperature ({T}{eff}) and interpret this as the preferential photodissociation of small PAHs in systems with higher {T}{eff} of which the stellar photons are more energetic. In addition, the PAH size shows a moderate correlation with the red-ward wavelength shift of the 7.7 μm PAH feature that is commonly observed in disks around cool stars. The ionization fraction of PAHs does not seem to correlate with any stellar parameters. This is because the charging of PAHs depends on not only the stellar properties (e.g., {T}{eff}, luminosity) but also their spatial distribution in the disks. The marginally negative correlation between PAH size and stellar age suggests that continuous replenishment of PAHs via the outgassing of cometary bodies and/or the collisional grinding of planetesimals and asteroids is required to maintain the abundance of small PAHs against complete destruction by photodissociation.

IUE observations of new A star candidate proto-planetary systems

NASA Technical Reports Server (NTRS)

Grady, Carol A.

1994-01-01

As a result of the detection of accreting gas in the A5e PMS Herbig Ae star, HR 5999, most of the observations for this IUE program were devoted to Herbig Ae stars rather than to main sequence A stars. Mid-UV emission at optical minimum light was detected for UX Ori (A1e), BF Ori (A5e), and CQ Tau (F2e). The presence of accreting gas in HD 45677 and HD 50138 prompted reclassification of these stars as Herbig Be stars rather than as protoplanetary nebulae. Detailed results are discussed.

WISE Catches a Runaway Star in Flames

NASA Image and Video Library

2010-11-24

NASA Wide-field Infrared Survey captured this view of a runaway star racing away from its original home. Surrounded by a glowing cloud of gas and dust, the star AE Aurigae appears on fire. Appropriately, the cloud is called the Flaming Star nebula.

Using He I λ10830 to Diagnose Mass Flows Around Herbig Ae/Be Stars

NASA Astrophysics Data System (ADS)

Cauley, Paul W.; Johns-Krull, Christopher M.

2015-01-01

The pre-main sequence Herbig Ae/Be stars (HAEBES) are the intermediate mass cousins of the low mass T Tauri stars (TTSs). However, it is not clear that the same accretion and mass outflow mechanisms operate identically in both mass regimes. Classical TTSs (CTTSs) accrete material from their disks along stellar magnetic field lines in a scenario called magnetospheric accretion. Magnetospheric accretion requires a strong stellar dipole field in order to truncate the inner gas disk. These fields are either absent or very weak on a large majority of HAEBES, challenging the view that magnetospheric accretion is the dominant accretion mechanism. If magnetospheric accretion does not operate similarly around HAEBES as it does around CTTSs, then strong magnetocentrifugal outflows, which are directly linked to accretion and are ubiquitous around CTTSs, may be driven less efficiently from HAEBE systems. Here we present high resolution spectroscopic observations of the He I λ10830 line in a sample of 48 HAEBES. He I λ10830 is an excellent tracer of both mass infall and outflow which is directly manifested as red and blue-shifted absorption in the profile morphologies. These features, among others, are common in our sample. The occurrence of both red and blue-shifted absorption profiles is less frequent, however, than is found in CTTSs. Statistical contingency tests confirm this difference at a significant level. In addition, we find strong evidence for smaller disk truncation radii in the objects displaying red-shifted absorption profiles. This is expected for HAEBES experiencing magnetospheric accretion based on their large rotation rates and weak magnetic field strengths. Finally, the low incidence of blue-shifted absorption in our sample compared to CTTSs and the complete lack of simultaneous red and blue-shifted absorption features suggests that magnetospheric accretion in HAEBES is less efficient at driving strong outflows. The stellar wind-like outflows that are

New radio detections of early-type pre-main-sequence stars

NASA Technical Reports Server (NTRS)

Skinner, Stephen L.; Brown, Alexander; Linsky, Jeffrey L.

1990-01-01

Results of VLA radio continuum observations of 13 early-type pre-main-sequence stars selected from the 1984 catalog of Finkenzeller and Mundt are presented. The stars HD 259431 and MWC 1080 were detected at 3.6 cm, while HD 200775 and TY CrA were detected at both 3.6 and 6 cm. The flux density of HD 200775 has a frequency dependence consistent with the behavior expected for free-free emission originating in a fully ionized wind. However, an observation in A configuration suggests that the source geometry may not be spherically symmetric. In contrast, the spectral index of TY CrA is negative with a flux behavior implying nonthermal emission. The physical mechanism responsible for the nonthermal emission has not yet been identified, although gyrosynchrotron and synchrotron processes cannot be ruled out.

VLBA DETERMINATION OF THE DISTANCE TO NEARBY STAR-FORMING REGIONS. IV. A PRELIMINARY DISTANCE TO THE PROTO-HERBIG AeBe STAR EC 95 IN THE SERPENS CORE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dzib, Sergio; Loinard, Laurent; Rodriguez, Luis F.

2010-08-01

Using the Very Long Base Array, we observed the young stellar object EC 95 in the Serpens cloud core at eight epochs from 2007 December to 2009 December. Two sources are detected in our field and are shown to form a tight binary system. The primary (EC 95a) is a 4-5 M {sub sun} proto-Herbig AeBe object (arguably the youngest such object known), whereas the secondary (EC 95b) is most likely a low-mass T Tauri star. Interestingly, both sources are non-thermal emitters. While T Tauri stars are expected to power a corona because they are convective while they go downmore » the Hayashi track, intermediate-mass stars approach the main sequence on radiative tracks. Thus, they are not expected to have strong superficial magnetic fields, and should not be magnetically active. We review several mechanisms that could produce the non-thermal emission of EC 95a and argue that the observed properties of EC 95a might be most readily interpreted if it possessed a corona powered by a rotation-driven convective layer. Using our observations, we show that the trigonometric parallax of EC 95 is {pi} = 2.41 {+-} 0.02 mas, corresponding to a distance of 414.9{sup +4.4} {sub -4.3} pc. We argue that this implies a distance to the Serpens core of 415 {+-} 5 pc and a mean distance to the Serpens cloud of 415 {+-} 25 pc. This value is significantly larger than previous estimates (d {approx} 260 pc) based on measurements of the extinction suffered by stars in the direction of Serpens. A possible explanation for this discrepancy is that these previous observations picked out foreground dust clouds associated with the Aquila Rift system rather than Serpens itself.« less

ASCA X-ray observations of pre-main-sequence stars

NASA Technical Reports Server (NTRS)

Skinner, S. L.; Walter, F. M.; Yamauchi, S.

1996-01-01

The results of recent Advanced Satellite for Cosmology and Astrophysics (ASCA) X-ray observations of two pre-main sequence stars are presented: the weak emission line T Tauri star HD 142361, and the Herbig Ae star HD 104237. The solid state imaging spectrometer spectra for HD 142361 shows a clear emission line from H-like Mg 7, and spectral fits reveal a multiple temperature plasma with a hot component of at least 16 MK. The spectra of HD 104237 show a complex temperature structure with the hottest plasma at temperatures of greater than 30 MK. It is concluded that mechanisms that predict only soft X-ray emission can be dismissed for Herbig Ae stars.

Inferring a Gap in the Group II Disk of the Herbig Ae/Be Star HD 142666

NASA Astrophysics Data System (ADS)

Ezra Rubinstein, Adam; Macías, Enrique; Espaillat, Catherine; Calvet, Nuria; Robinson, Connor; Zhang, Ke

2018-01-01

Disks around Herbig Ae/Be (HAeBe) stars have been classified into Group I or Group II, which are thought to be flared and flat disks respectively. Most Group I disks have been shown to have large gaps, suggesting ongoing planet formation, while no large gaps have been found in Group II disks. We analyzed the Group II disk of HD 142666 using irradiated accretion disk modeling of the broad-band spectral energy distribution along with the 1.3 millimeter spatial brightness distribution traced by Atacama Large Millimeter and Submillimeter Array (ALMA) observations. Our model is able to reproduce the available data, predicting a high degree of settling in the disk, which is consistent with the Group II classification of HD 142666. Although the ALMA observations did not have enough angular resolution to fully resolve the inner parts of the disk, the observed visibilities and synthesized image can only be reproduced when including a gap between ~5 to 12 au in our disk model. In addition, we also infer that the disk has an outer radius of ~65 au, which may be evidence of radial migration of dust or an unseen, low-mass companion that is truncating the outer disk. These results may suggest that Group II disks around HAeBe stars have gaps, possibly carved by young giant planets in the disk. Further ALMA observations of HD 142666 and other Group II disks are needed to discern if gaps are common in this class of objects, as well as to reveal their possible origin.

A Cavity of Large Grains in the Disk around the Group II Herbig Ae/Be Star HD 142666

NASA Astrophysics Data System (ADS)

Rubinstein, A. E.; Macías, E.; Espaillat, C. C.; Zhang, K.; Calvet, N.; Robinson, C.

2018-06-01

Herbig Ae/Be (HAeBe) stars have been classified into Group I or Group II, and were initially thought to be flared and flat disks, respectively. Several Group I sources have been shown to have large gaps, suggesting ongoing planet formation, while no large gaps have been found in the disks of Group II sources. We analyzed the disk around the Group II source, HD 142666, using irradiated accretion disk modeling of the broadband spectral energy distribution along with the 1.3 mm spatial brightness distribution traced by Atacama Large Millimeter and Submillimeter Array (ALMA) observations. Our model reproduces the available data, predicting a high degree of dust settling in the disk, which is consistent with the Group II classification of HD 142666. In addition, the observed visibilities and synthesized image could only be reproduced when including a depletion of large grains out to ∼ 16 au in our disk model, although the ALMA observations did not have enough angular resolution to fully resolve the inner parts of the disk. These results may suggest that some disks around Group II HAeBe stars have cavities of large grains as well. Further ALMA observations of Group II sources are needed to discern how commonly cavities occur in this class of objects, as well as to reveal their possible origins.

A tenuous X-ray corona enveloping AE Aquarii

NASA Astrophysics Data System (ADS)

Venter, L. A.; Meintjes, P. J.

2007-06-01

In this paper we propose that the observed unpulsed X-ray emission in AE Aquarii is the result of a very tenuous hot corona associated with the secondary star, which is pumped magnetohydrodynamically by the propeller action of the fast rotating white dwarf. It is shown that the closed coronal field of the secondary star envelops a substantial portion of the binary system, including the fast rotating magnetized white dwarf. This implies that the propeller outflow of material in AE Aquarii is initiated inside an enveloping magnetic cavity. The outflow crossing the secondary dead-zone field constitutes a βgen = (8πρv2esc/B2) >> 1 plasma, acting as a magnetohydrodynamic generator resulting in the induction of field-aligned currents in these closed magnetospheric circuits where βcir = (8πnkT/B2) << 1. The Ohmic heating of the coronal circuit can readily account for a Tx >= 107 K plasma in the coronal flux tubes connecting the generator and the stellar surface. Further, the bremsstrahlung losses of the thermal electrons in the coronal circuit can readily drive the observed unpulsed X-ray luminosity of Lx ~ 1031 ergs -1, which correlates with the luminosity and relatively large source implied by recent XMM-Newton observations.

Optical spectrophotometry of oscillations and flickering in AE Aquarii

NASA Technical Reports Server (NTRS)

Welsh, William F.; Horne, Keith; Oke, J. B.

1993-01-01

We observed rapid variations in the nova-like cataclysmic variable AE Aquarii for 1.7 hr with 4.3 s time resolution using the 30-channel (3227-10494 A) spectrophotometer on the Hale 5 m telescope. The 16.5 and 33.0 s oscillations show a featureless blue spectrum that can be represented by a blackbody with temperature and area much smaller than the accretion disk. Models consisting of the sum of a K star spectrum and a hydrogen slab in LTE at T = 6000-10,000 K can fit the spectrum of AE Aquarii reasonably well. The spectrum of a flare indicates optically thin gas with T = 8000-12,000 K. The energy released by the flare is large compared to typical stellar flares.

Evolutionary status of isolated B[e] stars

NASA Astrophysics Data System (ADS)

Lee, Chien-De; Chen, Wen-Ping; Liu, Sheng-Yuan

2016-08-01

Aims: We study a sample of eight B[e] stars with uncertain evolutionary status to shed light on the origin of their circumstellar dust. Methods: We performed a diagnostic analysis on the spectral energy distribution beyond infrared wavelengths, and conducted a census of neighboring region of each target to ascertain its evolutionary status. Results: In comparison to pre-main sequence Herbig stars, these B[e] stars show equally substantial excess emission in the near-infrared, indicative of existence of warm dust, but much reduced excess at longer wavelengths, so the dusty envelopes should be compact in size. Isolation from star-forming regions excludes the possibility of their pre-main sequence status. Six of our targets, including HD 50138, HD 45677, CD-24 5721, CD-49 3441, MWC 623, and HD 85567, have been previously considered as FS CMa stars, whereas HD 181615/6 and HD 98922 are added to the sample by this work. We argue that the circumstellar grains of these isolated B[e] stars, already evolved beyond the pre-main sequence phase, should be formed in situ. This is in contrast to Herbig stars, which inherit large grains from parental molecular clouds. It has been thought that HD 98922, in particular, is a Herbig star because of its large infrared excess, but we propose it being in a more evolved stage. Because dust condenses out of stellar mass loss in an inside-out manner, the dusty envelope is spatially confined, and anisotropic mass flows, or anomalous optical properties of tiny grains, lead to the generally low line-of-sight extinction toward these stars.

Milli-arcsecond images of the Herbig Ae star HD 163296

NASA Astrophysics Data System (ADS)

Renard, S.; Malbet, F.; Benisty, M.; Thiébaut, E.; Berger, J.-P.

2010-09-01

Context. The very close environments of young stars are the hosts of fundamental physical processes, such as planet formation, star-disk interactions, mass accretion, and ejection. The complex morphological structure of these environments has been confirmed by the now quite rich data sets obtained for a few objects by near-infrared long-baseline interferometry. Aims: We gathered numerous interferometric measurements for the young star HD 163296 with various interferometers (VLTI, IOTA, KeckI and CHARA), allowing for the first time an image independent of any a priori model to be reconstructed. Methods: Using the Multi-aperture image Reconstruction Algorithm (MiRA), we reconstruct images of HD 163296 in the H and K bands. We compare these images with reconstructed images obtained from simulated data using a physical model of the environment of HD 163296. Results: We obtain model-independent H and K-band images of the surroundings of HD 163296. The images detect several significant features that we can relate to an inclined asymmetric flared disk around HD 163296 with the strongest intensity at about 4-5 mas. Because of the incomplete spatial frequency coverage, we cannot state whether each of them individually is peculiar in any way. Conclusions: For the first time, milli-arcsecond images of the environment of a young star are produced. These images confirm that the morphology of the close environment of young stars is more complex than the simple models used in the literature so far.

Search for gamma-ray emission from AE Aquarii with seven year of Fermi LAT observations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jian; Torres, Diego F.; Rea, Nanda

2016-11-14

AE Aquarii (AE Aqr) is a cataclysmic binary hosting one of the fastest rotating (more » $${P}_{\\mathrm{spin}}$$ = 33.08 s) white dwarfs (WDs) known. Based on seven years of Fermi Large Area Telescope (LAT) Pass 8 data, we report on a deep search for gamma-ray emission from AE Aqr. When using X-ray observations from ASCA, XMM-Newton, Chandra, Swift, Suzaku, and NuSTAR, spanning 20 years, we substantially extend and improve the spin ephemeris of AE Aqr. Using this ephemeris, we searched for gamma-ray pulsations at the spin period of the WD. We detected no gamma-ray pulsations above 3σ significance. Neither phase-averaged gamma-ray emission nor gamma-ray variability of AE Aqr is detected by Fermi LAT. We also impose the most restrictive upper limit to the gamma-ray flux from AE Aqr to date: $$1.3\\times {10}^{-12}$$ erg cm -2 s -1 in the 100 MeV–300 GeV energy range, providing constraints on models.« less

Spatially extended polycyclic aromatic hydrocarbons in circumstellar disks around T Tauri and Herbig Ae stars

NASA Astrophysics Data System (ADS)

Geers, V. C.; van Dishoeck, E. F.; Visser, R.; Pontoppidan, K. M.; Augereau, J.-C.; Habart, E.; Lagrange, A. M.

2007-12-01

Aims:Our aim is to determine the presence and location of the emission from polycyclic aromatic hydrocarbons (PAHs) towards low and intermediate mass young stars with disks using large aperture telescopes. Methods: VLT-VISIR N-band spectra and VLT-ISAAC and VLT-NACO L-band spectra of 29 sources are presented, spectrally resolving the 3.3, 8.6, 11.2, and 12.6 μm PAH features. Spatial-extent profiles of the features and the continuum emission have been derived and used to associate the PAH emission with the disks. The results are discussed in the context of recent PAH-emission disk models. Results: The 3.3, 8.6, and 11.2 μm PAH features are detected toward a small fraction of the T Tauri stars, with typical upper limits between 1 × 10-15 and 5 × 10-17 W m-2. All 11.2 μm detections from a previous Spitzer survey are confirmed with (tentative) 3.3 μm detections, and both the 8.6 and the 11.2 μm features are detected in all PAH sources. For 6 detections, the spatial extent of the PAH features is confined to scales typically smaller than 0.12-0.34'', consistent with the radii of 12-60 AU disks at their distances (typically 150 pc). For 3 additional sources, WL 16, HD 100546, and TY CrA, one or more of the PAH features are more extended than the hot dust continuum of the disk, whereas for Oph IRS 48, the size of the resolved PAH emission is confirmed as smaller than for the large grains. For HD 100546, the 3.3 μm emission is confined to a small radial extent of 12±3 AU, most likely associated with the outer rim of the gap in this disk. Gaps with radii out to 10-30 AU may also affect the observed PAH extent for other sources. For both Herbig Ae and T Tauri stars, the small measured extents of the 8.6 and 11.2 μm features are consistent with larger (≥100 carbon atoms) PAHs. Based on observations obtained at the European Southern Observatory, Paranal, Chile, within the observing programs 164.I-0605 (ISAAC May 2002), 074.C-0413 (NACO, March/April 2005), 075.C-0420

A Decade of MWC 758 Disk Images: Where Are the Spiral-arm-driving Planets?

NASA Astrophysics Data System (ADS)

Ren, Bin; Dong, Ruobing; Esposito, Thomas M.; Pueyo, Laurent; Debes, John H.; Poteet, Charles A.; Choquet, Élodie; Benisty, Myriam; Chiang, Eugene; Grady, Carol A.; Hines, Dean C.; Schneider, Glenn; Soummer, Rémi

2018-04-01

Large-scale spiral arms have been revealed in scattered light images of a few protoplanetary disks. Theoretical models suggest that such arms may be driven by and corotate with giant planets, which has called for remarkable observational efforts to look for them. By examining the rotation of the spiral arms for the MWC 758 system over a 10 year timescale, we are able to provide dynamical constraints on the locations of their perturbers. We present reprocessed Hubble Space Telescope (HST)/NICMOS F110W observations of the target in 2005, and the new Keck/NIRC2 L‧-band observations in 2017. MWC 758's two well-known spiral arms are revealed in the NICMOS archive at the earliest observational epoch. With additional Very Large Telescope (VLT)/SPHERE data, our joint analysis leads to a pattern speed of 0\\buildrel{\\circ}\\over{.} {6}-0\\buildrel{\\circ\\over{.} 6}+3\\buildrel{\\circ\\over{.} 3} {yr}}-1 at 3σ for the two major spiral arms. If the two arms are induced by a perturber on a near-circular orbit, its best-fit orbit is at 89 au (0.″59), with a 3σ lower limit of 30 au (0.″20). This finding is consistent with the simulation prediction of the location of an arm-driving planet for the two major arms in the system.

Occultations from an Active Accretion Disk in a 72-day Detached Post-Algol System Detected by K2

NASA Astrophysics Data System (ADS)

Zhou, G.; Rappaport, S.; Nelson, L.; Huang, C. X.; Senhadji, A.; Rodriguez, J. E.; Vanderburg, A.; Quinn, S.; Johnson, C. I.; Latham, D. W.; Torres, G.; Gary, B. L.; Tan, T. G.; Johnson, M. C.; Burt, J.; Kristiansen, M. H.; Jacobs, T. L.; LaCourse, D.; Schwengeler, H. M.; Terentev, I.; Bieryla, A.; Esquerdo, G. A.; Berlind, P.; Calkins, M. L.; Bento, J.; Cochran, W. D.; Karjalainen, M.; Hatzes, A. P.; Karjalainen, R.; Holden, B.; Butler, R. P.

2018-02-01

Disks in binary systems can cause exotic eclipsing events. MWC 882 (BD –22 4376, EPIC 225300403) is such a disk-eclipsing system identified from observations during Campaign 11 of the K2 mission. We propose that MWC 882 is a post-Algol system with a B7 donor star of mass 0.542+/- 0.053 {M}ȯ in a 72-day orbit around an A0 accreting star of mass 3.24+/- 0.29 {M}ȯ . The 59.9+/- 6.2 {R}ȯ disk around the accreting star occults the donor star once every orbit, inducing 19-day long, 7% deep eclipses identified by K2 and subsequently found in pre-discovery All-Sky Automated Survey and All Sky Automated Survey for Supernovae observations. We coordinated a campaign of photometric and spectroscopic observations for MWC 882 to measure the dynamical masses of the components and to monitor the system during eclipse. We found the photometric eclipse to be gray to ≈1%. We found that the primary star exhibits spectroscopic signatures of active accretion, and we observed gas absorption features from the disk during eclipse. We suggest that MWC 882 initially consisted of a ≈3.6 M ⊙ donor star transferring mass via Roche lobe overflow to a ≈2.1 M ⊙ accretor in a ≈7-day initial orbit. Through angular momentum conservation, the donor star is pushed outward during mass transfer to its current orbit of 72 days. The observed state of the system corresponds with the donor star having left the red giant branch ∼0.3 Myr ago, terminating active mass transfer. The present disk is expected to be short-lived (102 yr) without an active feeding mechanism, presenting a challenge to this model.

The Beta Pictoris Phenomenon in Young Stars With Accreting Gas

NASA Technical Reports Server (NTRS)

Grady, Carol A.

1999-01-01

Program Hae2BPIC resulted in usable ISO spectra of three young, Herbig Ae stars: HR 5999 (A7e, t=0.6 Myr), SV Cep (al-2e, t=1-3 Myr), and MW Vul (Al-2e, t=1-3 Myr). While too small a sample to pursue our original goal of surveying the silicate emission in these young, protoplanetary disk systems, comparison of these data with ground-based IR spectra, and published ISO observations of other HAe stars (especially the posters at PPIV) reveals the following: The known binary stars in the sample show signatures of partially crystal line silicate features by t=0.6 Myr, at an epoch when ostensibly single Herbig Ae stars have substantially stronger silicate emission dominated by amorphous grains. The known binary stars also show deficits in the optically thick continuum flux relative to coeval single stars. Comparison of ISO spectra indicates that the flux deficit seen in WD 163296 over 10-100 microns relative to AB Aur reflects a real deficit of material interior to 300.

VizieR Online Data Catalog: Hα emitting sources around MWC758 (Huelamo+, 2018)

NASA Astrophysics Data System (ADS)

Huelamo, N.; Chauvin, G.; Schmid, H. M.; Quanz, S. P.; Whelan, E.; Lillo-Box, J.; Barrado, D.; Montesinos, B.; Alcala, J. M.; Benisty, M.; de Gregorio-Monsalvo, I.; Mendigutia, I.; Bouy, H.; Merin, B.; de Boer, J.; Garufi, A.; Pantin, E.

2018-06-01

The SPHERE Open Time observations (096.C-0267.A) were obtained on December 30, 2015. The ZIMPOL instrument of SPHERE was used in spectral and angular differential imaging modes. In addition to the pupil stabilized mode, ZIMPOL simultaneously imaged MWC758 in two different filters: B_Ha (λc=655.6nm and δλ=5.5nm) and Cnt_Ha (λc=644.9nm and δλ=4.1nm). We obtained 190 individual exposures of 60 seconds each, resulting in a total exposure time of 3 hours on-source (from 02:20UT to 05:24 UT). (2 data files).

INTERFEROMETRIC UPPER LIMITS ON MILLIMETER POLARIZATION OF THE DISKS AROUND DG Tau, GM Aur, AND MWC 480

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hughes, A. Meredith; Hull, Charles L. H.; Plambeck, Richard L.

2013-04-15

Millimeter-wavelength polarization measurements offer a promising method for probing the geometry of magnetic fields in circumstellar disks. Single dish observations and theoretical work have hinted that magnetic field geometries might be predominantly toroidal, and that disks should exhibit millimeter polarization fractions of 2%-3%. While subsequent work has not confirmed these high polarization fractions, either the wavelength of observation or the target sources differed from the original observations. Here we present new polarimetric observations of three nearby circumstellar disks at 2'' resolution with the Submillimeter Array and the Combined Array for Research in Millimeter Astronomy. We reobserve GM Aur and DGmore » Tau, the systems in which millimeter polarization detections have been claimed. Despite higher resolution and sensitivity at wavelengths similar to the previous observations, the new observations do not show significant polarization. We also add observations of a new HAeBe system, MWC 480. These observations demonstrate that a very low ({approx}<0.5%) polarization fraction is probably common at large ({approx}>100 AU) scales in bright circumstellar disks. We suggest that high-resolution observations may be worthwhile to probe magnetic field structure on linear distances smaller than the disk scale height, as well as in regions closer to the star that may have larger MRI-induced magnetic field strengths.« less

Progress on Magnetism in Massive Stars (MiMeS)

NASA Astrophysics Data System (ADS)

Neiner, C.; Alecian, E.; Mathis, S.

2011-12-01

We present the MiMeS project, which aims at studying all aspects of magnetism in massive stars to understand their characteristics, origin, incidence, evolution, and impact on other physical processes. We show examples of recent observational results obtained within this project on pulsating B stars (β Cephei and SPB stars) as well as Herbig Ae/Be stars. Recent theoretical progress obtained within MiMeS on the configuration and stability of magnetic fields is also summarized.

From Star Wars to 'turf wars'.

PubMed

1999-09-01

Just as we are witnessing the re-emergence of Star Wars, it seems the 'turf wars' that have dogged A&E care are back. Since its inception as a specialty, A&E nurses have been accused of being 'Jacks (and Jill's, to be politically correct) of all trades and masters of none'. The inference being that all we do is 'mind' patients until they receive definitive care. Clearly this is not the case. As A&E nurses have demonstrated over the years, our skills are in the recognition and management of acute illness or injury, regardless of the patient's age, physical or psychological condition. Rather than being a 'master of none' we are masters of immediate care.

A model for the spectroscopic variations of the peculiar symbiotic star MWC 560

NASA Technical Reports Server (NTRS)

Shore, Steven N.; Aufdenberg, Jason P.; Michalitsianos, A. G.

1994-01-01

In this note, we show that the ultraviolet and optical spectroscopic variability of this unique symbiotic star can be understood in terms of a time variable collimated stellar wind with a rapid acceleration near the source. Using the radial velocities observed during the ultraviolet bright phase, we find that a variation in the mass loss rate of a factor of ten can explain the ultraviolet spectral changes. The acceleration is far faster than normally observed in radiatively driven stellar winds and may be due to mechanical driving of the outflow from the disk.

Modeling and Observations of Massive Binaries with the B[e] Phenomenon

NASA Astrophysics Data System (ADS)

Lobel, A.; Martayan, C.; Mehner, A.; Groh, J. H.

2017-02-01

We report a long-term high-resolution spectroscopic monitoring program of LBVs and candidate LBVs with Mercator-HERMES. Based on 7 years of data, we recently showed that supergiant MWC 314 is a (Galactic) semi-detached eccentric binary with stationary permitted and forbidden emission lines in the optical and near-IR region. MWC 314 is a luminous and massive probable LBV star showing a strongly orbitally-modulated wind variability. We observe discrete absorption components in P Cyg He I lines signaling large-scale wind structures. In 2014 XMM observed X-rays indicating strong wind-wind collision in the close binary system (a ≃1 AU). A VLT-NACO imaging survey recently revealed that MWC 314 is a triple hierarchical system. We present a 3-D non-LTE radiative transfer model of the extended asymmetric wind structure around the primary B0 supergiant for modeling the orbital variability of P Cyg absorption (v∞˜1200 km s-1) in He I lines. An analysis of the HERMES monitoring spectra of the Galactic LBV star MWC 930 however does not show clear indications of a spectroscopic binary. The detailed long-term spectroscopic variability of this massive B[e] star is very similar to the spectroscopic variability of the prototypical blue hypergiant S Dor in the LMC. We observe prominent P Cyg line shapes in MWC 930 that temporarily transform into split absorption line cores during variability phases of its S Dor cycle over the past decade with a brightening in V of ˜ 1.2 mag. The line splitting phenomenon is very similar to the split metal line cores observed in pulsating Yellow Hypergiants ρ Cas (F-K Ia+) and HR 8752 (A-K Ia+) with [Ca II] and [N II] emission lines. We propose the line core splitting in MWC 930 is due to optically thick central line emission produced in the inner ionized wind region becoming mechanically shock-excited with the increase of R* and decrease of Teff of the LBV.

On the Absence of Non-thermal X-Ray Emission around Runaway O Stars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toalá, J. A.; Oskinova, L. M.; Ignace, R.

Theoretical models predict that the compressed interstellar medium around runaway O stars can produce high-energy non-thermal diffuse emission, in particular, non-thermal X-ray and γ -ray emission. So far, detection of non-thermal X-ray emission was claimed for only one runaway star, AE Aur. We present a search for non-thermal diffuse X-ray emission from bow shocks using archived XMM-Newton observations for a clean sample of six well-determined runaway O stars. We find that none of these objects present diffuse X-ray emission associated with their bow shocks, similarly to previous X-ray studies toward ζ Oph and BD+43°3654. We carefully investigated multi-wavelength observations ofmore » AE Aur and could not confirm previous findings of non-thermal X-rays. We conclude that so far there is no clear evidence of non-thermal extended emission in bow shocks around runaway O stars.« less

Free energy changes and components implicit in the MWC allosteric model for the cooperative oxygen binding of hemoglobin.#

PubMed Central

Bucci, Enrico

2013-01-01

Hill’s plots of oxygen binding isotherms reveal the presence of a transition between two different oxygen affinities at the beginning and end of the isotherm. They correspond to the two conformations anticipated by the MWC model, namely the T and R conformations at the beginning and end of oxygen binding, when the lower affinity of the T form develops into the higher affinity of the R form. The difference between the binding Gibbs free energies changes of the two affinities (ΔGL) is the free energy of binding cooperativity. Notably ΔGL is positive in favor of the T form, that moves to a higher energy level upon oxygen release. Osmotic stress reveals a higher volume/surface ratio of deoxyHb, with a positive ΔGW also in favor of the T form . Increasing protein concentration shifts the isotherms to the right indicating the formation of intermediate polymeric forms. Enthalpy of the intermediates show a strong absorption of heat at the third oxygenation step due to polymers formation with quinary, and above, structures. The disassembly of intermediate polymers releases energy with a negative ΔG that compensates and allow the positivity of ΔGL. High energy polymers are the barrier preventing the relaxation of the T and R conformations into one another. The MWC allosteric model is the best justification of oxygen binding cooperativity . PMID:23710673

A mid-IR study of the circumstellar environment of Herbig Be stars

NASA Astrophysics Data System (ADS)

Verhoeff, A. P.; Waters, L. B. F. M.; van den Ancker, M. E.; Min, M.; Stap, F. A.; Pantin, E.; van Boekel, R.; Acke, B.; Tielens, A. G. G. M.; de Koter, A.

2012-02-01

Context. The study of the formation of massive stars is complicated because of the short times scales, large distances, and obscuring natal clouds. There are observational and theoretical indications that the circumstellar environment of Herbig Be (HBe) stars is substantially different from that of their lower mass counterparts, the T Tauri and Herbig Ae stars. Aims: We map the spatial distribution and mineralogy of the warm circumstellar dust of a sample of HBe stars. We compare our results to a sample of less massive Herbig Ae stars. Methods: We used literature photometry to obtain optical extinctions and stellar parameters of the targets. We obtained N-band imaging and long-slit spectroscopic data with the VISIR instrument at the VLT and we analyzed these data. We performed photometry of the images and extracted spatial information. We corrected the spectra for extinction and performed mineralogical fits. We fitted Gaussian profiles to characterize the spatial extent of the spectra along the VISIR slit. Results: We find that the mid-infrared (IR) emission of the HBe stars is typically characterized by a circumstellar disk that efficiently reprocesses a substantial portion of the stellar flux. The mid-IR flux levels, the spatial compactness, and the dust composition are quite similar to those of the Herbig Ae stars. We find upper limits to the full-width-at-half-maximum (FWHM) size of the mid-IR emission of ~500 AU. The main differences with the lower mass stars are the lower overall IR excess with a greater variety in shapes, the weaker PAH reprocessing power, and the lack of a silica-forsterite relation. The discrepancies between VISIR and IRAS photometry, the far-IR contributions and the large PAH sizes of HBe stars are attributed to natal clouds. Conclusions: Our results suggest that the Herbig Be disks are flatter than those around lower mass stars and they are likely truncated from the outside by photoevaporation. Based on observations collected at the

A Multi-instrument and Multi-wavelength High Angular Resolution Study of MWC 614: Quantum Heated Particles Inside the Disk Cavity

NASA Astrophysics Data System (ADS)

Kluska, Jacques; Kraus, Stefan; Davies, Claire L.; Harries, Tim; Willson, Matthew; Monnier, John D.; Aarnio, Alicia; Baron, Fabien; Millan-Gabet, Rafael; Ten Brummelaar, Theo; Che, Xiao; Hinkley, Sasha; Preibisch, Thomas; Sturmann, Judit; Sturmann, Laszlo; Touhami, Yamina

2018-03-01

High angular resolution observations of young stellar objects are required to study the inner astronomical units of protoplanetary disks in which the majority of planets form. As they evolve, gaps open up in the inner disk regions and the disks are fully dispersed within ∼10 Myr. MWC 614 is a pretransitional object with a ∼10 au radius gap. We present a set of high angular resolution observations of this object including SPHERE/ZIMPOL polarimetric and coronagraphic images in the visible, Keck/NIRC2 near-infrared (NIR) aperture masking observations, and Very Large Telescope Interferometer (AMBER, MIDI, and PIONIER) and Center for High Angular Resolution Astronomy (CLASSIC and CLIMB) long-baseline interferometry at infrared wavelengths. We find that all the observations are compatible with an inclined disk (i ∼ 55° at a position angle of ∼20°–30°). The mid-infrared data set confirms that the disk inner rim is at 12.3 ± 0.4 au from the central star. We determined an upper mass limit of 0.34 M ⊙ for a companion inside the cavity. Within the cavity, the NIR emission, usually associated with the dust sublimation region, is unusually extended (∼10 au, 30 times larger than the theoretical sublimation radius) and indicates a high dust temperature (T ∼ 1800 K). As a possible result of companion-induced dust segregation, quantum heated dust grains could explain the extended NIR emission with this high temperature. Our observations confirm the peculiar state of this object where the inner disk has already been accreted onto the star, exposing small particles inside the cavity to direct stellar radiation. Based on observations made with the Keck observatory (NASA program ID N104N2) and with ESO telescopes at the Paranal Observatory (ESO program IDs 073.C-0720, 077.C-0226, 077.C-0521, 083.C-0984, 087.C-0498(A), 190.C-0963, 095.C-0883) and with the Center for High Angular Resolution Astronomy observatory.

CO and H(3)(+) in the protoplanetary disk around the star HD141569.

PubMed

Brittain, Sean D; Rettig, Terrence W

2002-07-04

Massive planets have now been found orbiting about 80 stars. A long outstanding question critical to theories of planet formation has been the timescale on which gas-giant planets form; in particular, stars more massive than the Sun may blow away the surrounding gas associated with their formation more quickly than it can be accumulated by the protoplanetary cores. Evidence for a protoplanet around a Herbig AeBe star (such stars are 2 3 times more massive than the Sun) would constrain the timescale of planet formation. Here we report the detection of CO and H(3)(+) emission from the 5-10-million-year-old Herbig AeBe star HD141569. We interpret the CO data as indicating that the inner disk surrounding the star is past the early phase of accretion and planetesimal formation, and that most of the gas has been cleared out to a distance of more than 17 astronomical units. CO effectively destroys H(3)(+) (ref. 2), so their presence in the same source is surprising. Moreover, H(3)(+) line emission has previously been detected only from the atmospheres of the giant planets in the Solar System. The H(3)(+) and CO may therefore be distributed in the disk at different circumstellar distances, or, alternatively, H(3)(+) may be located in the extended envelope of a protoplanet.

First Images from the PIONIER/VLTI optical interferometry imaging survey of Herbig Ae/Be stars

NASA Astrophysics Data System (ADS)

Kluska, Jacques; Malbet, Fabien; Berger, Jean-Philippe; Benisty, Myriam; Lazareff, Bernard; Le Bouquin, Jean-Baptiste; Baron, Fabien; Dominik, Carsten; Isella, Andrea; Juhasz, Attila; Kraus, Stefan; Lachaume, Régis; Ménard, François; Millan-Gabet, Rafael; Monnier, John; Pinte, Christophe; Thi, Wing-Fai; Thiébaut, Eric; Zins, Gérard

2013-07-01

The morphology of the close environment of herbig stars is being revealed step by step and appears to be quite complex. Many physical phenomena could interplay : the dust sublimation causing a puffed-up inner rim, a dusty halo, a dusty wind or an inner gaseous component. To investigate more deeply these regions, getting images at the first Astronomical Unit scale is crucial. This has become possible with near infrared instruments on the VLTi. We are carrying out the first Large Program survey of HAeBe stars with statistics on the geometry of these objects at the first astronomical unit scale and the first images of the very close environment of some of them. We have developed a new numerical method specific to young stellar objects which removes the stellar component reconstructing an image of the environment only. To do so we are using the differences in the spectral behaviour between the star and its environment. The images reveal the environement which is not polluted by the star and allow us to derive the best fit for the flux ratio and the spectral slope between the two components (stellar and environmental). We present the results of the survey with some statistics and the frist images of Herbig stars made by PIONIER on the VLTi.

Towards the effect of acoustic emission (AE) sensor positioning within AE signal parameters in sliding on bulk ultrafine-grained materials

NASA Astrophysics Data System (ADS)

Filippov, A. V.; Tarasov, S. Yu.; Podgornykh, O. A.; Chazov, P. A.; Shamarin, N. N.; Filippova, E. O.

2017-12-01

The effect of AE sensor positioning on the bulk ultrafine-grained materials used for sliding against steel ball has been investigated. Two versions of AE sensor positioning have been tested and showed the different attenuation levels. The experimentally obtained AE signal waveforms have been analyzed under the AE signal parameters such as a median frequency and AE energy. It was established that the AE sensor positioned on the sample supporting plate in the vicinity of the sample tested allowed redistribution of the signal energy from a low-frequency to high-frequency range as well as extending the median frequency range as compared to those obtained by mounting the sensor on the immobile sample holder.

A&E nursing in Iraq.

PubMed

Thompson, Lieutenant Sarah

2004-01-01

I am an A&E nurse. I work 12-hour shifts on a rotation of 12 hours on, 24 hours off, seven days a week. It takes me five minutes to walk to the A&E department where I work. As well as the scissors and pen torch you would expect a nurse to carry, I take body armour, goggles and a helmet to work. With outdoor temperatures regularly reaching more than 50°C, water is essential for any journey, however short. As I am sure you can tell, I do not work in an ordinary A&E department.

Association appoints new RCN A&E Chair.

PubMed

1999-09-01

Lynda Holt, A&E Clinical Manager at Warwick Hospital has become Chair of the RCN A&E Nursing Association following the resignation of Karen Castille who has been seconded to the Department of Health (England) to work on the A&E modernisation programme.

19 CFR 192.11 - Description of the AES.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 2 2012-04-01 2012-04-01 false Description of the AES. 192.11 Section 192.11... TREASURY (CONTINUED) EXPORT CONTROL Filing of Export Information Through the Automated Export System (AES) § 192.11 Description of the AES. AES is a voluntary program that allows all exporters required to report...

15 CFR 758.2 - Automated Export System (AES).

Code of Federal Regulations, 2014 CFR

2014-01-01

... 15 Commerce and Foreign Trade 2 2014-01-01 2014-01-01 false Automated Export System (AES). 758.2... CLEARANCE REQUIREMENTS § 758.2 Automated Export System (AES). The Census Bureau's Foreign Trade Statistics...) electronically using the Automated Export System (AES). In order to use AES, you must apply directly to the...

15 CFR 758.2 - Automated Export System (AES).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 15 Commerce and Foreign Trade 2 2013-01-01 2013-01-01 false Automated Export System (AES). 758.2... CLEARANCE REQUIREMENTS § 758.2 Automated Export System (AES). The Census Bureau's Foreign Trade Statistics...) electronically using the Automated Export System (AES). In order to use AES, you must apply directly to the...

19 CFR 192.11 - Description of the AES.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 2 2014-04-01 2014-04-01 false Description of the AES. 192.11 Section 192.11... TREASURY (CONTINUED) EXPORT CONTROL Filing of Export Information Through the Automated Export System (AES) § 192.11 Description of the AES. AES is a voluntary program that allows all exporters required to report...

19 CFR 192.11 - Description of the AES.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 2 2011-04-01 2011-04-01 false Description of the AES. 192.11 Section 192.11... TREASURY (CONTINUED) EXPORT CONTROL Filing of Export Information Through the Automated Export System (AES) § 192.11 Description of the AES. AES is a voluntary program that allows all exporters required to report...

19 CFR 192.11 - Description of the AES.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 2 2013-04-01 2013-04-01 false Description of the AES. 192.11 Section 192.11... TREASURY (CONTINUED) EXPORT CONTROL Filing of Export Information Through the Automated Export System (AES) § 192.11 Description of the AES. AES is a voluntary program that allows all exporters required to report...

15 CFR 758.2 - Automated Export System (AES).

Code of Federal Regulations, 2012 CFR

2012-01-01

... 15 Commerce and Foreign Trade 2 2012-01-01 2012-01-01 false Automated Export System (AES). 758.2... CLEARANCE REQUIREMENTS § 758.2 Automated Export System (AES). The Census Bureau's Foreign Trade Statistics...) electronically using the Automated Export System (AES). In order to use AES, you must apply directly to the...

Effect of ECAP processing on corrosion resistance of AE21 and AE42 magnesium alloys

NASA Astrophysics Data System (ADS)

Minárik, P.; Král, R.; Janeček, M.

2013-09-01

Corrosion properties of AE21 and AE42 magnesium alloys were investigated in the extruded state and after subsequent 8 passes of Equal Channel Angular Pressing (ECAP) via route Bc, by Electrochemical Impedance Spectroscopy (EIS) in 0.1 M NaCl solution. The resulting microstructure was observed by the Transmission Electron Microscope (TEM) and the Scanning Electron Microscope (SEM). Corrosion layer created after 7 days of immersion was observed by (SEM) in order to explain different evolution of the corrosion resistance after ECAP processing in both alloys. It was found that Al-rich Al11RE3 dispersed particles (present in both alloys) strongly influence the corrosion process and enhance the corrosion resistance. Ultra-fine grained structure was found to reduce the corrosion resistance in AE21. On the other hand, the microstructure of AE42 after ECAP and particularly the better distribution of the alloying elements in the matrix enhance the corrosion resistance when compared to the extruded material.

Educational preparation: Research in A&E.

PubMed

1996-02-01

Just as there is an evergrowing number of educational opportunities for A&E (1), there is growing recognition of the importance of research in the development of the 'art and science' of nursing. In A&E nursing there is a need to develop the science of our specialty to further enhance the treatment and care of patients. This paper asks some fundamental questions about research and researchers in A&E and identifies key research priorities for the coming years.

Imaging the cool stars in the interacting binaries AE Aqr, BV Cen and V426 Oph

NASA Astrophysics Data System (ADS)

Watson, C. A.; Steeghs, D.; Dhillon, V. S.; Shahbaz, T.

2007-10-01

It is well known that magnetic activity in late-type stars increases with increasing rotation rate. Using inversion techniques akin to medical imaging, the rotationally broadened profiles from such stars can be used to reconstruct `Doppler images' of the distribution of cool, dark starspots on their stellar surfaces. Interacting binaries, however, contain some of the most rapidly rotating late-type stars known and thus provide important tests of stellar dynamo models. Furthermore, magnetic activity is thought to play a key role in their evolution, behaviour and accretion dynamics. Despite this, we know comparatively little about the magnetic activity and its influence on such binaries. In this review we summarise the concepts behind indirect imaging of these systems, and present movies of the starspot distributions on the cool stars in some interacting binaries. We conclude with a look at the future opportunities that such studies may provide.

The AE-8 trapped electron model environment

NASA Technical Reports Server (NTRS)

Vette, James I.

1991-01-01

The machine sensible version of the AE-8 electron model environment was completed in December 1983. It has been sent to users on the model environment distribution list and is made available to new users by the National Space Science Data Center (NSSDC). AE-8 is the last in a series of terrestrial trapped radiation models that includes eight proton and eight electron versions. With the exception of AE-8, all these models were documented in formal reports as well as being available in a machine sensible form. The purpose of this report is to complete the documentation, finally, for AE-8 so that users can understand its construction and see the comparison of the model with the new data used, as well as with the AE-4 model.

Reflective intuition: defining A&E nursing.

PubMed

Cook, A

1996-01-01

A&E nurses may develop intuitive feelings about the condition of their patients. A&E nurses are practising reflective intuition, based on experience. Recognition of this skill could raise the professional status of nursing.

(abstract) Airborne Emission Spectrometer (AES)

NASA Technical Reports Server (NTRS)

Beer, Reinhard

1994-01-01

AES is a low-cost analog of the TES downlooking modes. Because AES operates at ambient temperature, limb-viewing is not possible. The first flight of AES took place in April 1994 on the NASA P3B aircraft out of Wallops Island, VA. While planned as an engineering test flight, spectra were successfully acquired both over the Atlantic Ocean and the area of the Great Dismal Swamp on the Virginia-North Carolina border. At this writing (July 1994), a second series of flights on the NASA DC8 aircraft out of Ames RC,CA is in progress. By the time of the workshop, a third series using the NASA C130 should have been accomplished.

An ALMA Survey of DCN/H13CN and DCO+/H13CO+ in Protoplanetary Disks

NASA Astrophysics Data System (ADS)

Huang, Jane; Öberg, Karin I.; Qi, Chunhua; Aikawa, Yuri; Andrews, Sean M.; Furuya, Kenji; Guzmán, Viviana V.; Loomis, Ryan A.; van Dishoeck, Ewine F.; Wilner, David J.

2017-02-01

The deuterium enrichment of molecules is sensitive to their formation environment. Constraining patterns of deuterium chemistry in protoplanetary disks is therefore useful for probing how material is inherited or reprocessed throughout the stages of star and planet formation. We present ALMA observations at ˜0.″6 resolution of DCO+, H13CO+, DCN, and H13CN in the full disks around T Tauri stars AS 209 and IM Lup, in the transition disks around T Tauri stars V4046 Sgr and LkCa 15, and in the full disks around Herbig Ae stars MWC 480 and HD 163296. We also present ALMA observations of HCN in the IM Lup disk. DCN, DCO+, and H13CO+ are detected in all disks, and H13CN in all but the IM Lup disk. We find efficient deuterium fractionation for the sample, with estimates of disk-averaged DCO+/HCO+ and DCN/HCN abundance ratios ranging from ˜0.02-0.06 and ˜0.005-0.08, respectively, which is comparable to values reported for other interstellar environments. The relative distributions of DCN and DCO+ vary between disks, suggesting that multiple formation pathways may be needed to explain the diverse emission morphologies. In addition, gaps and rings observed in both H13CO+ and DCO+ emission provide new evidence that DCO+ bears a complex relationship with the location of the midplane CO snowline.

Photospheres of hot stars. III - Luminosity effects at spectral type 09.5

NASA Technical Reports Server (NTRS)

Voels, Stephen A.; Bohannan, Bruce; Abbott, David C.; Hummer, D. G.

1989-01-01

Hydrogen and helium line profiles with high signal-to-noise ratios were obtained for four stars of spectral type 09.5 (Alpha Cam, Xi Ori A, Delta Ori A,AE Aur) that form a sequence in luminosity: Ia, Ib, II, V. The basic stellar parameters of these stars are determined by fitting the observed line profiles of weak photospheric absorption lines with profiles from models which include the effect of radiation scattered back onto the photosphere from their stellar winds, an effect referred to as wind blanketing. For these stars, the inclusion of wind blanketing is significant only for the most luminous star, Alpha Cam, for which the effective temperature was shifted about -2000 K relative to an unblanketed model.

Multiple Lookup Table-Based AES Encryption Algorithm Implementation

NASA Astrophysics Data System (ADS)

Gong, Jin; Liu, Wenyi; Zhang, Huixin

Anew AES (Advanced Encryption Standard) encryption algorithm implementation was proposed in this paper. It is based on five lookup tables, which are generated from S-box(the substitution table in AES). The obvious advantages are reducing the code-size, improving the implementation efficiency, and helping new learners to understand the AES encryption algorithm and GF(28) multiplication which are necessary to correctly implement AES[1]. This method can be applied on processors with word length 32 or above, FPGA and others. And correspondingly we can implement it by VHDL, Verilog, VB and other languages.

15 CFR Appendix B to Part 30 - AES Filing Codes

Code of Federal Regulations, 2013 CFR

2013-01-01

... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false AES Filing Codes B Appendix B to Part..., DEPARTMENT OF COMMERCE FOREIGN TRADE REGULATIONS Pt. 30, App. B Appendix B to Part 30—AES Filing Codes Part I... Manifest Use Only by AES Carriers) AE Shipment information filed through AES (See §§ 30.50 through 30.58...

15 CFR Appendix B to Part 30 - AES Filing Codes

Code of Federal Regulations, 2012 CFR

2012-01-01

... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false AES Filing Codes B Appendix B to Part..., DEPARTMENT OF COMMERCE FOREIGN TRADE REGULATIONS Pt. 30, App. B Appendix B to Part 30—AES Filing Codes Part I... Manifest Use Only by AES Carriers) AE Shipment information filed through AES (See §§ 30.50 through 30.58...

Characterization of Aes nuclear foci in colorectal cancer cells

PubMed Central

Itatani, Yoshiro; Sonoshita, Masahiro; Kakizaki, Fumihiko; Okawa, Katsuya; Stifani, Stefano; Itoh, Hideaki; Sakai, Yoshiharu; Taketo, M. Mark

2016-01-01

Amino-terminal enhancer of split (Aes) is a member of Groucho/Transducin-like enhancer (TLE) family. Aes is a recently found metastasis suppressor of colorectal cancer (CRC) that inhibits Notch signalling, and forms nuclear foci together with TLE1. Although some Notch-associated proteins are known to form subnuclear bodies, little is known regarding the dynamics or functions of these structures. Here, we show that Aes nuclear foci in CRC observed under an electron microscope are in a rather amorphous structure, lacking surrounding membrane. Investigation of their behaviour during the cell cycle by time-lapse cinematography showed that Aes nuclear foci dissolve during mitosis and reassemble after completion of cytokinesis. We have also found that heat shock cognate 70 (HSC70) is an essential component of Aes foci. Pharmacological inhibition of the HSC70 ATPase activity with VER155008 reduces Aes focus formation. These results provide insight into the understanding of Aes-mediated inhibition of Notch signalling. PMID:26229111

Distant star clusters of the Milky Way in MOND

NASA Astrophysics Data System (ADS)

Haghi, H.; Baumgardt, H.; Kroupa, P.

2011-03-01

We determine the mean velocity dispersion of six Galactic outer halo globular clusters, AM 1, Eridanus, Pal 3, Pal 4, Pal 15, and Arp 2 in the weak acceleration regime to test classical vs. modified Newtonian dynamics (MOND). Owing to the nonlinearity of MOND's Poisson equation, beyond tidal effects, the internal dynamics of clusters is affected by the external field in which they are immersed. For the studied clusters, particle accelerations are much lower than the critical acceleration a0 of MOND, but the motion of stars is neither dominated by internal accelerations (ai ≫ ae) nor external accelerations (ae ≫ ai). We use the N-body code N-MODY in our analysis, which is a particle-mesh-based code with a numerical MOND potential solver developed by Ciotti et al. (2006, ApJ, 640, 741) to derive the line-of-sight velocity dispersion by adding the external field effect. We show that Newtonian dynamics predicts a low-velocity dispersion for each cluster, while in modified Newtonian dynamics the velocity dispersion is much higher. We calculate the minimum number of measured stars necessary to distinguish between Newtonian gravity and MOND with the Kolmogorov-Smirnov test. We also show that for most clusters it is necessary to measure the velocities of between 30 to 80 stars to distinguish between both cases. Therefore the observational measurement of the line-of-sight velocity dispersion of these clusters will provide a test for MOND.

Changes in histopathology and cytokeratin AE1/AE3 expression in skin graft with different time on Indonesian local cats.

PubMed

Erwin; Etriwati; Gunanti; Handharyani, Ekowati; Noviana, Deni

2017-06-01

A good skin graft histopathology is followed by formation of hair follicle, sweat gland, sebaceous gland, blood vessel, lightly dense connective tissue, epidermis, and dermis layer. This research aimed to observe histopathology feature and cytokeratin AE1/AE3 expression on cat skin post skin grafting within a different period of time. Nine male Indonesian local cats aged 1-2 years old weighing 3-4 kg were separated into three groups. First surgery created defect wound of 2 cm × 2 cm in size to whole groups. The wounds were left alone for several days, differing in interval between each group, respectively: Group I (for 2 days), Group II (for 4 days), and Group III (for 6 days). The second surgery was done to each group which harvested skin of thoracic area and applied it on recipient wound bed. On day 24 th post skin graft was an examination of histopathology and cytokeratin AE1/AE3 immunohistochemistry. Group I donor skin's epidermis layer had not formed completely whereas epidermis of donor skin of Groups II and III had completely formed. In all group hair follicle, sweat gland, sebaceous gland, and neovascularization were found. The density of connective tissue in Group I was very solid than other groups. Cytokeratin AE1/AE3 expression was found on donor skin's epithelial cell in epidermis and dermis layer with very brown intensity for Group II, brown intensity for Group II, and lightly brown for Group I. Histopathological structure and cytokeratin AE1/AE3 expression post skin graft are better in Groups II and III compared to Group I.

NuSTAR Results and Future Plans for Magnetar and Rotation-Powered Pulsar Observations

NASA Technical Reports Server (NTRS)

An, H.; Kaspi, V. M.; Archibald, R.; Bachetti, M.; Bhalerao, V.; Bellm, E. C.; Beloborodov, A. M.; Boggs, S. E.; Chakrabarty, D.; Christensen, F. E.;

Characterization of Aes nuclear foci in colorectal cancer cells.

PubMed

Itatani, Yoshiro; Sonoshita, Masahiro; Kakizaki, Fumihiko; Okawa, Katsuya; Stifani, Stefano; Itoh, Hideaki; Sakai, Yoshiharu; Taketo, M Mark

2016-01-01

Amino-terminal enhancer of split (Aes) is a member of Groucho/Transducin-like enhancer (TLE) family. Aes is a recently found metastasis suppressor of colorectal cancer (CRC) that inhibits Notch signalling, and forms nuclear foci together with TLE1. Although some Notch-associated proteins are known to form subnuclear bodies, little is known regarding the dynamics or functions of these structures. Here, we show that Aes nuclear foci in CRC observed under an electron microscope are in a rather amorphous structure, lacking surrounding membrane. Investigation of their behaviour during the cell cycle by time-lapse cinematography showed that Aes nuclear foci dissolve during mitosis and reassemble after completion of cytokinesis. We have also found that heat shock cognate 70 (HSC70) is an essential component of Aes foci. Pharmacological inhibition of the HSC70 ATPase activity with VER155008 reduces Aes focus formation. These results provide insight into the understanding of Aes-mediated inhibition of Notch signalling. © The Authors 2015. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

Narrow-band Imagery with the Goddard Fabry-Perot: Probing the Epoch of Active Accretion for PMS Stars

NASA Technical Reports Server (NTRS)

Woodgate, Bruce E.; Grady, C.; Endres, M.; Williger, G.

2006-01-01

The STIS coronagraphic imaging sample of I'MS stars was surveyed with the Goddard Fabry-Perot (GFP) interferometer to determine what fraction of the stars drive jets, whether there is any difference in behavior for a group of intermediate-mass stars as compared with T Tauri stars, and to search for evolutionary effects. Compared to broad band imaging, the FGP achieves an emission-line nebulosity-to-star contrast gain of between 500 and 3000. To date, we have detected jets associated with classical T Tauri stars spanning a factor of 280 in mass accretion rate in approximately 50% of the STIS coronagraphic imaging sample. We also detected jets or Herbig-HARO knots associated with 5 Herbig Ae stars, all younger than 8 Myr, for a detection fraction which is smaller than the T Tauri survey.

AE Recorder Characteristics and Development.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Partridge, Michael E.; Curtis, Shane Keawe; McGrogan, David Paul

2016-11-01

The Anomalous Environment Recorder (AE Recorder) provides a robust data recording capability for multiple high-shock applications including earth penetrators. The AE Recorder, packaged as a 2.4" di ameter cylinder 3" tall, acquires 12 accelerometer, 2 auxiliary, and 6 discrete signal channels at 250k samples / second. Recording depth is 213 seconds plus 75ms of pre-trigger data. The mechanical, electrical, and firmware are described as well as support electro nics designed for the first use of the recorder.

Test and Verification of AES Used for Image Encryption

NASA Astrophysics Data System (ADS)

Zhang, Yong

2018-03-01

In this paper, an image encryption program based on AES in cipher block chaining mode was designed with C language. The encryption/decryption speed and security performance of AES based image cryptosystem were tested and used to compare the proposed cryptosystem with some existing image cryptosystems based on chaos. Simulation results show that AES can apply to image encryption, which refutes the widely accepted point of view that AES is not suitable for image encryption. This paper also suggests taking the speed of AES based image encryption as the speed benchmark of image encryption algorithms. And those image encryption algorithms whose speeds are lower than the benchmark should be discarded in practical communications.

A More Compact AES

NASA Astrophysics Data System (ADS)

Canright, David; Osvik, Dag Arne

We explore ways to reduce the number of bit operations required to implement AES. One way involves optimizing the composite field approach for entire rounds of AES. Another way is integrating the Galois multiplications of MixColumns with the linear transformations of the S-box. Combined with careful optimizations, these reduce the number of bit operations to encrypt one block by 9.0%, compared to earlier work that used the composite field only in the S-box. For decryption, the improvement is 13.5%. This work may be useful both as a starting point for a bit-sliced software implementation, where reducing operations increases speed, and also for hardware with limited resources.

22 CFR 120.30 - The Automated Export System (AES).

Code of Federal Regulations, 2012 CFR

2012-04-01

... 22 Foreign Relations 1 2012-04-01 2012-04-01 false The Automated Export System (AES). 120.30 Section 120.30 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.30 The Automated Export System (AES). The Automated Export System (AES) is the Department of...

22 CFR 120.30 - The Automated Export System (AES).

Code of Federal Regulations, 2014 CFR

2014-04-01

... 22 Foreign Relations 1 2014-04-01 2014-04-01 false The Automated Export System (AES). 120.30 Section 120.30 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.30 The Automated Export System (AES). The Automated Export System (AES) is the Department of...

22 CFR 120.30 - The Automated Export System (AES).

Code of Federal Regulations, 2011 CFR

2011-04-01

... 22 Foreign Relations 1 2011-04-01 2011-04-01 false The Automated Export System (AES). 120.30 Section 120.30 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.30 The Automated Export System (AES). The Automated Export System (AES) is the Department of...

22 CFR 120.30 - The Automated Export System (AES).

Code of Federal Regulations, 2013 CFR

2013-04-01

... 22 Foreign Relations 1 2013-04-01 2013-04-01 false The Automated Export System (AES). 120.30 Section 120.30 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.30 The Automated Export System (AES). The Automated Export System (AES) is the Department of...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Jane; Öberg, Karin I.; Qi, Chunhua

The deuterium enrichment of molecules is sensitive to their formation environment. Constraining patterns of deuterium chemistry in protoplanetary disks is therefore useful for probing how material is inherited or reprocessed throughout the stages of star and planet formation. We present ALMA observations at ∼0.″6 resolution of DCO{sup +}, H{sup 13}CO{sup +}, DCN, and H{sup 13}CN in the full disks around T Tauri stars AS 209 and IM Lup, in the transition disks around T Tauri stars V4046 Sgr and LkCa 15, and in the full disks around Herbig Ae stars MWC 480 and HD 163296. We also present ALMA observationsmore » of HCN in the IM Lup disk. DCN, DCO{sup +}, and H{sup 13}CO{sup +} are detected in all disks, and H{sup 13}CN in all but the IM Lup disk. We find efficient deuterium fractionation for the sample, with estimates of disk-averaged DCO{sup +}/HCO{sup +} and DCN/HCN abundance ratios ranging from ∼0.02–0.06 and ∼0.005–0.08, respectively, which is comparable to values reported for other interstellar environments. The relative distributions of DCN and DCO{sup +} vary between disks, suggesting that multiple formation pathways may be needed to explain the diverse emission morphologies. In addition, gaps and rings observed in both H{sup 13}CO{sup +} and DCO{sup +} emission provide new evidence that DCO{sup +} bears a complex relationship with the location of the midplane CO snowline.« less

22 CFR 120.30 - The Automated Export System (AES).

Code of Federal Regulations, 2010 CFR

2010-04-01

... DEFINITIONS § 120.30 The Automated Export System (AES). The Automated Export System (AES) is the Department of Commerce, Bureau of Census, electronic filing of export information. The AES shall serve as the primary...). Also, requests for special reporting may be made by DDTC on a case-by-case basis, (e.g., compliance...

Crack classification in concrete beams using AE parameters

NASA Astrophysics Data System (ADS)

Bahari, N. A. A. S.; Shahidan, S.; Abdullah, S. R.; Ali, N.; Zuki, S. S. Mohd; Ibrahim, M. H. W.; Rahim, M. A.

2017-11-01

The acoustic emission (AE) technique is an effective tool for the evaluation of crack growth. The aim of this study is to evaluate crack classification in reinforced concrete beams using statistical analysis. AE has been applied for the early monitoring of reinforced concrete structures using AE parameters such as average frequency, rise time, amplitude counts and duration. This experimental study focuses on the utilisation of this method in evaluating reinforced concrete beams. Beam specimens measuring 150 mm × 250 mm × 1200 mm were tested using a three-point load flexural test using Universal Testing Machines (UTM) together with an AE monitoring system. The results indicated that RA value can be used to determine the relationship between tensile crack and shear movement in reinforced concrete beams.

Energy efficiency analysis and implementation of AES on an FPGA

NASA Astrophysics Data System (ADS)

Kenney, David

The Advanced Encryption Standard (AES) was developed by Joan Daemen and Vincent Rjimen and endorsed by the National Institute of Standards and Technology in 2001. It was designed to replace the aging Data Encryption Standard (DES) and be useful for a wide range of applications with varying throughput, area, power dissipation and energy consumption requirements. Field Programmable Gate Arrays (FPGAs) are flexible and reconfigurable integrated circuits that are useful for many different applications including the implementation of AES. Though they are highly flexible, FPGAs are often less efficient than Application Specific Integrated Circuits (ASICs); they tend to operate slower, take up more space and dissipate more power. There have been many FPGA AES implementations that focus on obtaining high throughput or low area usage, but very little research done in the area of low power or energy efficient FPGA based AES; in fact, it is rare for estimates on power dissipation to be made at all. This thesis presents a methodology to evaluate the energy efficiency of FPGA based AES designs and proposes a novel FPGA AES implementation which is highly flexible and energy efficient. The proposed methodology is implemented as part of a novel scripting tool, the AES Energy Analyzer, which is able to fully characterize the power dissipation and energy efficiency of FPGA based AES designs. Additionally, this thesis introduces a new FPGA power reduction technique called Opportunistic Combinational Operand Gating (OCOG) which is used in the proposed energy efficient implementation. The AES Energy Analyzer was able to estimate the power dissipation and energy efficiency of the proposed AES design during its most commonly performed operations. It was found that the proposed implementation consumes less energy per operation than any previous FPGA based AES implementations that included power estimations. Finally, the use of Opportunistic Combinational Operand Gating on an AES cipher

Power Consumption and Calculation Requirement Analysis of AES for WSN IoT.

PubMed

Hung, Chung-Wen; Hsu, Wen-Ting

2018-05-23

Because of the ubiquity of Internet of Things (IoT) devices, the power consumption and security of IoT systems have become very important issues. Advanced Encryption Standard (AES) is a block cipher algorithm is commonly used in IoT devices. In this paper, the power consumption and cryptographic calculation requirement for different payload lengths and AES encryption types are analyzed. These types include software-based AES-CB, hardware-based AES-ECB (Electronic Codebook Mode), and hardware-based AES-CCM (Counter with CBC-MAC Mode). The calculation requirement and power consumption for these AES encryption types are measured on the Texas Instruments LAUNCHXL-CC1310 platform. The experimental results show that the hardware-based AES performs better than the software-based AES in terms of power consumption and calculation cycle requirements. In addition, in terms of AES mode selection, the AES-CCM-MIC64 mode may be a better choice if the IoT device is considering security, encryption calculation requirement, and low power consumption at the same time. However, if the IoT device is pursuing lower power and the payload length is generally less than 16 bytes, then AES-ECB could be considered.

Submillimeter studies of main-sequence stars

NASA Technical Reports Server (NTRS)

Zuckerman, B.; Becklin, E. E.

1993-01-01

JCMT maps of the 800-micron emission from Vega, Fomalhaut, and Beta Pictoris are interpreted to indicate that they are not ringed by large reservoirs of distant orbiting dust particles that are too cold to have been detected by IRAS. A search for 800-micron emission from stars in the Pleiades and Ursa Majoris open clusters is reported. In comparison with the mass of dust particles near T Tauri and Herbig Ae stars, the JCMT data indicate a decline in dust mass during the initial 3 x 10 exp 8 yr that a star spends on the main sequence that is at least as rapid as (time) exp -2. It is estimated that in the Kuiper belt the ratio of total mass carried by small particles to that carried by comets is orders of magnitude smaller than this ratio is 1 AU from the sun. If 800-micron opacities calculated by Pollack et al. (1993) are correct, then the particles with radii less than 100 microns that dominate the FIR fluxes measured by IRAS cannot entirely account for the measured 800-micron fluxes at Vega, Beta Pic, and Fomalhaut; larger particles must be present as well.

Cloud Screening and Quality Control Algorithm for Star Photometer Data: Assessment with Lidar Measurements and with All-sky Images

NASA Technical Reports Server (NTRS)

Ramirez, Daniel Perez; Lyamani, H.; Olmo, F. J.; Whiteman, D. N.; Navas-Guzman, F.; Alados-Arboledas, L.

2012-01-01

This paper presents the development and set up of a cloud screening and data quality control algorithm for a star photometer based on CCD camera as detector. These algorithms are necessary for passive remote sensing techniques to retrieve the columnar aerosol optical depth, delta Ae(lambda), and precipitable water vapor content, W, at nighttime. This cloud screening procedure consists of calculating moving averages of delta Ae() and W under different time-windows combined with a procedure for detecting outliers. Additionally, to avoid undesirable Ae(lambda) and W fluctuations caused by the atmospheric turbulence, the data are averaged on 30 min. The algorithm is applied to the star photometer deployed in the city of Granada (37.16 N, 3.60 W, 680 ma.s.l.; South-East of Spain) for the measurements acquired between March 2007 and September 2009. The algorithm is evaluated with correlative measurements registered by a lidar system and also with all-sky images obtained at the sunset and sunrise of the previous and following days. Promising results are obtained detecting cloud-affected data. Additionally, the cloud screening algorithm has been evaluated under different aerosol conditions including Saharan dust intrusion, biomass burning and pollution events.

AE characteristic for monitoring of fatigue crack in steel bridge members

NASA Astrophysics Data System (ADS)

Yoon, Dong-Jin; Jung, Juong-Chae; Park, Philip; Lee, Seung-Seok

2000-06-01

Acoustic emission technique was employed for the monitoring of crack activity in both steel bridge members and laboratory specimen. Laboratory experiment was carried out to identify AE characteristics of fatigue cracks for compact tension specimen. The relationship between a stress intensity factor and AE signals activity as well as conventional AE parameter analysis was discussed. A field test was also conducted on a railway bridge, which contain several fatigue cracks. Crack activities were investigated while in service with strain measurement. From the results, in the laboratory tests, the features of three parameters such as the length of crack growth, the AE energy, and the cumulative AE events, showed the almost same trend in their increase as the number of fatigue cycle increased. From the comparisons of peak amplitude and AE energy with stress intensity factor, it was verified that the higher stress intensity factors generated AE signals with higher peak amplitude and a large number of AE counts. In the field test, real crack propagation signals were captured and the crack activity was verified in two cases.

High-cadence, High-resolution Spectroscopic Observations of Herbig Stars HD 98922 and V1295 Aquila

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aarnio, Alicia N.; Monnier, John D.; Calvet, Nuria

Recent observational work has indicated that mechanisms for accretion and outflow in Herbig Ae/Be star–disk systems may differ from magnetospheric accretion (MA) as it is thought to occur in T Tauri star–disk systems. In this work, we assess the temporal evolution of spectral lines probing accretion and mass loss in Herbig Ae/Be systems and test for consistency with the MA paradigm. For two Herbig Ae/Be stars, HD 98922 (B9e) and V1295 Aql (A2e), we have gathered multi-epoch (∼years) and high-cadence (∼minutes) high-resolution optical spectra to probe a wide range of kinematic processes. Employing a line equivalent width evolution correlation metricmore » introduced here, we identify species co-evolving (indicative of common line origin) via novel visualization. We interferometrically constrain often problematically degenerate parameters, inclination and inner-disk radius, allowing us to focus on the structure of the wind, magnetosphere, and inner gaseous disk in radiative transfer models. Over all timescales sampled, the strongest variability occurs within the blueshifted absorption components of the Balmer series lines; the strength of variability increases with the cadence of the observations. Finally, high-resolution spectra allow us to probe substructure within the Balmer series’ blueshifted absorption components: we observe static, low-velocity features and time-evolving features at higher velocities. Overall, we find the observed line morphologies and variability are inconsistent with a scaled-up T Tauri MA scenario. We suggest that as magnetic field structure and strength change dramatically with increasing stellar mass from T Tauri to Herbig Ae/Be stars, so too may accretion and outflow processes.« less

A large scale laboratory cage trial of Aedes densonucleosis virus (AeDNV).

PubMed

Wise de Valdez, Megan R; Suchman, Erica L; Carlson, Jonathan O; Black, William C

2010-05-01

Aedes aegypti (L.) (Diptera: Culicidae) the primary vector of dengue viruses (DENV1-4), oviposit in and around human dwellings, including sites difficult to locate, making control of this mosquito challenging. We explored the efficacy and sustainability of Aedes Densonucleosis Virus (AeDNV) as a biocontrol agent for Ae. aegypti in and among oviposition sites in large laboratory cages (> 92 m3) as a prelude to field trials. Select cages were seeded with AeDNV in a single oviposition site (OPS) with unseeded OPSs established at varied distances. Quantitative real-time polymerase chain reaction was used to track dispersal and accumulation of AeDNV among OPSs. All eggs were collected weekly from each cage and counted. We asked: (1) Is AeDNV dispersed over varying distances and can it accumulate and persist in novel OPSs? (2) Are egg densities reduced in AeDNV treated populations? AeDNV was dispersed to and sustained in novel OPSs. Virus accumulation in OPSs was positively correlated with egg densities and proximity to the initial infection source affected the timing of dispersal and maintenance of viral titers. AeDNV did not significantly reduce Ae. aegypti egg densities. The current study documents that adult female Ae. aegypti oviposition behavior leads to successful viral dispersal from treated to novel containers in large-scale cages; however, the AeDNV titers reached were not sufficient to reduce egg densities.

High-Energy X-Ray Detection of G359.89-0.08 (SGR A-E): Magnetic Flux Tube Emission Powered by Cosmic Rays?

NASA Technical Reports Server (NTRS)

Zhang, Shuo; Hailey, Charles J.; Baganoff, Frederick K.; Bauer, Franz E.; Boggs, Steven E.; Craig, William W.; Christensen, Finn E.; Gotthelf, Eric V.; Harrison, Fiona A.; Mori, Kaya;

Acoustic emissions (AE) monitoring of large-scale composite bridge components

NASA Astrophysics Data System (ADS)

Velazquez, E.; Klein, D. J.; Robinson, M. J.; Kosmatka, J. B.

2008-03-01

Acoustic Emissions (AE) has been successfully used with composite structures to both locate and give a measure of damage accumulation. The current experimental study uses AE to monitor large-scale composite modular bridge components. The components consist of a carbon/epoxy beam structure as well as a composite to metallic bonded/bolted joint. The bonded joints consist of double lap aluminum splice plates bonded and bolted to carbon/epoxy laminates representing the tension rail of a beam. The AE system is used to monitor the bridge component during failure loading to assess the failure progression and using time of arrival to give insight into the origins of the failures. Also, a feature in the AE data called Cumulative Acoustic Emission counts (CAE) is used to give an estimate of the severity and rate of damage accumulation. For the bolted/bonded joints, the AE data is used to interpret the source and location of damage that induced failure in the joint. These results are used to investigate the use of bolts in conjunction with the bonded joint. A description of each of the components (beam and joint) is given with AE results. A summary of lessons learned for AE testing of large composite structures as well as insight into failure progression and location is presented.

AE3D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spong, Donald A

AE3D solves for the shear Alfven eigenmodes and eigenfrequencies in a torodal magnetic fusion confinement device. The configuration can be either 2D (e.g. tokamak, reversed field pinch) or 3D (e.g. stellarator, helical reversed field pinch, tokamak with ripple). The equations solved are based on a reduced MHD model and sound wave coupling effects are not currently included.

19 CFR 192.11 - Description of the AES.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 2 2010-04-01 2010-04-01 false Description of the AES. 192.11 Section 192.11 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) EXPORT CONTROL Filing of Export Information Through the Automated Export System (AES...

Photoevaporating Disks around Young Stars: Ultracompact HII Regions and Protoplanetary Disks.

NASA Astrophysics Data System (ADS)

Johnstone, Douglas Ian

1995-01-01

Newly formed stars produce sufficient Lyman continuum luminosity phi to significantly alter the structure and evolution of the accretion disk surrounding them. In the absence of a stellar wind, a nearly static, photoionized, 10^4 K, disk atmosphere, with a scale height that increases with disk radius varpi as varpi^{3/2 }, forms inside the gravitational radius varpig ~ 1014(M_*/ M_odot) cm where M _* is the mass of the central star. This ionized atmosphere is maintained by both the direct radiation from the central star and the diffuse field produced in the disk atmosphere by the significant fraction of hydrogen recombinations directly to the ground state. Beyond varpig the material evaporated from the disk is capable of escaping from the system and produces an ionized disk wind. The mass-loss due to this disk wind peaks at varpig . The inclusion of a stellar wind into the basic picture reduces the height of the inner disk atmosphere and introduces a new scale radius varpi_ {w} where the thermal pressure of the material evaporated from the disk balances the ram pressure in the wind. In this case the mass-loss due to the disk wind peaks at varpiw and is enhanced over the no-wind case. The photoevaporation of disks around newly formed stars has significance to both ultracompact HII regions and the dispersal of solar-type nebulae. High mass stars are intrinsically hot and thus yield sufficient Lyman luminosity to create, even without a stellar wind, disk mass-loss rates of order 2 times 10 ^{-5}phi_sp{49} {1/2} M_odotyr ^{-1}, where phi 49 = phi/(10 49 Lyman continuum photons s^{-1}). This wind, which will last until the disk is dispersed, ~ 10^5 yrs if the disk mass is M_ {d}~0.3M_*, yields sizes, emission measures and ages consistent with observations of ultracompact HII regions. The well-observed high mass star MWC 349 may be the best example to date of an evaporating disk around a high mass star. On the other end of the stellar scale, many newly formed low

Herschel observations of the circumstellar environments of the Herbig Be stars R Mon and PDS 27

NASA Astrophysics Data System (ADS)

Jiménez-Donaire, M. J.; Meeus, G.; Karska, A.; Montesinos, B.; Bouwman, J.; Eiroa, C.; Henning, T.

2017-09-01

Context. The circumstellar environments of Herbig Be stars in the far-infrared are poorly characterised, mainly because they are often embedded and rather distant. The analysis of far-infrared spectroscopy allows us to make a major step forward by covering multiple rotational lines of molecules, e.g. CO, that are useful probes of the physical conditions of the gas. Aims: We characterise the gas and dust in the discs and environments of Herbig Be stars, and we compare the results with those of their lower-mass counterparts, the Herbig Ae stars. Methods: We report and analyse far-infrared observations of two Herbig Be stars, R Mon and PDS 27, obtained with the Herschel instruments PACS and SPIRE. We construct spectral energy distributions and derive the infrared excess. We extract line fluxes from the PACS and SPIRE spectra and construct rotational diagrams in order to estimate the excitation temperature of the gas. We derive CO, [O I] and [C I] luminosities to determine the physical conditions of the gas, and the dominant cooling mechanism. Results: We confirm that the Herbig Be stars are surrounded by remnants from their parental clouds, with an IR excess that mainly originates in a disc. In R Mon we detect [O I], [C I], [C II], CO (26 transitions), water and OH, while in PDS 27 we only detect [C I] and CO (8 transitions). We attribute the absence of OH and water in PDS 27 to UV photo-dissociation and photo-evaporation. From the rotational diagrams, we find several components for CO; we derive Trot949 ± 90 K, 358 ± 20 K and 77 ± 12 K for R Mon; 96 ± 12 K and 31 ± 4 K for PDS 27; and 25 ± 8 K and 27 ± 6 K for their respective compact neighbours. The forsterite feature at 69 μm was not detected in either of the sources, probably due to the lack of (warm) crystalline dust in a flat disc. We find that cooling by molecules is dominant in the Herbig Be stars, while this is not the case in Herbig Ae stars where cooling by [O I] dominates. Moreover, we show that in

Infrared Spectro-Interferometry of Massive Stars: Disks, Winds, Outflows, and Stellar Multiplicity

NASA Astrophysics Data System (ADS)

Kraus, Stefan

2007-06-01

Interferometry is the ultimate technology for overcoming the limitations which diffraction and the atmosphere-induced seeing impose on the resolution achievable with ground-based telescopes. The latest generation of long-baseline interferometric instruments (in particular VLTI/AMBER and VLTI/MIDI), combines the high spatial resolution (typically a few milliarcseconds) with spectroscopic capabilities, allowing one to characterize the geometry of a continuum-emitting region over a wide spectral range or to spatially resolve the emitting region of Doppler-broadened spectral lines in many velocity channels. One branch of astrophysics which might particularly benefit from these advances in technology is the study of massive (O-B type) stars. In order to characterize these stars and their companions and to study accretion and outflow processes in their vicinity with unprecedented angular resolution, we have performed interferometric studies on four key objects, representing the still most enigmatic evolutionary phases of massive stars; namely the pre-main-sequence (MWC 147, NGC 7538 IRS1, Theta 1 Orionis C) and the post-main-sequence phase (Eta Carinae). MWC 147: As indicated by its strong infrared excess, this young Herbig Be star (B6-type) is still associated with residual material from its formation; maybe arranged in a circumstellar disk. In order to investigate the geometry of the material, we combined, for the first time, long-baseline spectro-interferometric observations at near- (NIR) and mid-infrared (MIR) wavelengths (using VLTI/AMBER, VLTI/MIDI, and archival PTI data). Fitting analytic models to the obtained interferometric data revealed a significant elongation of the continuum-emitting region. For a physical interpretation, we modeled the geometry of the dust distribution using 2-D radiative transfer simulations of Keplerian disks with and without a puffed-up inner rim, simultaneously fitting the wavelength-dependent visibilities and the SED, which we

Testing fundamental physics with distant star clusters: theoretical models for pressure-supported stellar systems

NASA Astrophysics Data System (ADS)

Haghi, Hosein; Baumgardt, Holger; Kroupa, Pavel; Grebel, Eva K.; Hilker, Michael; Jordi, Katrin

2009-05-01

We investigate the mean velocity dispersion and the velocity dispersion profile of stellar systems in modified Newtonian dynamics (MOND), using the N-body code N-MODY, which is a particle-mesh-based code with a numerical MOND potential solver developed by Ciotti, Londrillo & Nipoti. We have calculated mean velocity dispersions for stellar systems following Plummer density distributions with masses in the range of 104 to 109Msolar and which are either isolated or immersed in an external field. Our integrations reproduce previous analytic estimates for stellar velocities in systems in the deep MOND regime (ai, ae << a0), where the motion of stars is either dominated by internal accelerations (ai >> ae) or constant external accelerations (ae >> ai). In addition, we derive for the first time analytic formulae for the line-of-sight velocity dispersion in the intermediate regime (ai ~ ae ~ a0). This allows for a much-improved comparison of MOND with observed velocity dispersions of stellar systems. We finally derive the velocity dispersion of the globular cluster Pal14 as one of the outer Milky Way halo globular clusters that have recently been proposed as a differentiator between Newtonian and MONDian dynamics.

77 FR 15098 - AES Hawaii, Inc.; Notice of Petition for Temporary Waiver

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-14

...] AES Hawaii, Inc.; Notice of Petition for Temporary Waiver Take notice that on March 5, 2012, pursuant... and Procedure, 18 CFR 292.205(c), AES Hawaii, Inc. (AES Hawaii) filed a Request for Temporary Waiver..., Hawaii. AES Hawaii makes such a request because of a forced boiler outage in the fourth quarter of 2011...

The global compendium of Aedes aegypti and Ae. albopictus occurrence

PubMed Central

Kraemer, Moritz U. G.; Sinka, Marianne E.; Duda, Kirsten A.; Mylne, Adrian; Shearer, Freya M.; Brady, Oliver J.; Messina, Jane P.; Barker, Christopher M.; Moore, Chester G.; Carvalho, Roberta G.; Coelho, Giovanini E.; Van Bortel, Wim; Hendrickx, Guy; Schaffner, Francis; Wint, G. R. William; Elyazar, Iqbal R. F.; Teng, Hwa-Jen; Hay, Simon I.

2015-01-01

Aedes aegypti and Ae. albopictus are the main vectors transmitting dengue and chikungunya viruses. Despite being pathogens of global public health importance, knowledge of their vectors’ global distribution remains patchy and sparse. A global geographic database of known occurrences of Ae. aegypti and Ae. albopictus between 1960 and 2014 was compiled. Herein we present the database, which comprises occurrence data linked to point or polygon locations, derived from peer-reviewed literature and unpublished studies including national entomological surveys and expert networks. We describe all data collection processes, as well as geo-positioning methods, database management and quality-control procedures. This is the first comprehensive global database of Ae. aegypti and Ae. albopictus occurrence, consisting of 19,930 and 22,137 geo-positioned occurrence records respectively. Both datasets can be used for a variety of mapping and spatial analyses of the vectors and, by inference, the diseases they transmit. PMID:26175912

The global compendium of Aedes aegypti and Ae. albopictus occurrence

NASA Astrophysics Data System (ADS)

Kraemer, Moritz U. G.; Sinka, Marianne E.; Duda, Kirsten A.; Mylne, Adrian; Shearer, Freya M.; Brady, Oliver J.; Messina, Jane P.; Barker, Christopher M.; Moore, Chester G.; Carvalho, Roberta G.; Coelho, Giovanini E.; van Bortel, Wim; Hendrickx, Guy; Schaffner, Francis; Wint, G. R. William; Elyazar, Iqbal R. F.; Teng, Hwa-Jen; Hay, Simon I.

2015-07-01

Aedes aegypti and Ae. albopictus are the main vectors transmitting dengue and chikungunya viruses. Despite being pathogens of global public health importance, knowledge of their vectors’ global distribution remains patchy and sparse. A global geographic database of known occurrences of Ae. aegypti and Ae. albopictus between 1960 and 2014 was compiled. Herein we present the database, which comprises occurrence data linked to point or polygon locations, derived from peer-reviewed literature and unpublished studies including national entomological surveys and expert networks. We describe all data collection processes, as well as geo-positioning methods, database management and quality-control procedures. This is the first comprehensive global database of Ae. aegypti and Ae. albopictus occurrence, consisting of 19,930 and 22,137 geo-positioned occurrence records respectively. Both datasets can be used for a variety of mapping and spatial analyses of the vectors and, by inference, the diseases they transmit.

15 CFR Appendix D to Part 30 - AES Filing Citation, Exemption and Exclusion Legends

Code of Federal Regulations, 2013 CFR

2013-01-01

... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false AES Filing Citation, Exemption and... Appendix D to Part 30—AES Filing Citation, Exemption and Exclusion Legends I. USML Proof of Filing Citation AES ITN Example: AES X20060101987654. II. AES Proof of Filing Citation subpart A § 30.7 AES ITN...

15 CFR Appendix D to Part 30 - AES Filing Citation, Exemption and Exclusion Legends

Code of Federal Regulations, 2011 CFR

2011-01-01

... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false AES Filing Citation, Exemption and... Appendix D to Part 30—AES Filing Citation, Exemption and Exclusion Legends I. USML Proof of Filing Citation AES ITN Example: AES X20060101987654. II. AES Proof of Filing Citation subpart A § 30.7 AES ITN...

15 CFR Appendix D to Part 30 - AES Filing Citation, Exemption and Exclusion Legends

Code of Federal Regulations, 2012 CFR

2012-01-01

... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false AES Filing Citation, Exemption and... Appendix D to Part 30—AES Filing Citation, Exemption and Exclusion Legends I. USML Proof of Filing Citation AES ITN Example: AES X20060101987654. II. AES Proof of Filing Citation subpart A § 30.7 AES ITN...

15 CFR Appendix D to Part 30 - AES Filing Citation, Exemption and Exclusion Legends

Code of Federal Regulations, 2014 CFR

2014-01-01

... 15 Commerce and Foreign Trade 1 2014-01-01 2014-01-01 false AES Filing Citation, Exemption and... Appendix D to Part 30—AES Filing Citation, Exemption and Exclusion Legends I. USML Proof of Filing Citation AES ITN Example: AES X20060101987654. II. AES Proof of Filing Citation subpart A § 30.7 AES ITN...

Reduced DIDS-sensitive chloride conductance in Ae1-/- mouse erythrocytes

PubMed Central

Alper, Seth L.; Vandorpe, David H.; Peters, Luanne L.; Brugnara, Carlo

2008-01-01

The resting membrane potential of the human erythrocyte is largely determined by a constitutive Cl- conductance ∼100-fold greater than the resting cation conductance. The 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS)-sensitive electroneutral Cl- transport mediated by the human erythroid Cl-/HCO3- exchanger, AE1 (SLC4A1, band 3) is ≥10,000-fold greater than can be accounted for by the Cl- conductance of the red cell. The molecular identities of conductive anion pathways across the red cell membrane remain poorly defined. We have examined red cell Cl- conductance in the Ae1-/- mouse as a genetic test of the hypothesis that Ae1 mediates DIDS-sensitive Cl- conductance in mouse red cells. We report here that wildtype mouse red cell membrane potential resembles that of human red cells in the predominance of its Cl- conductance. We show with four technical approaches that the DIDS-sensitive component of erythroid Cl- conductance is reduced or absent from Ae1-/- red cells. These results are consistent with the hypothesis that the Ae1 anion exchanger polypeptide can operate infrequently in a conductive mode. However, the fragile red cell membrane of the Ae1-/- mouse red cell exhibits reduced abundance or loss of multiple polypeptides. Thus, loss of one or more distinct, DIDS-sensitive anion channel polypeptide(s) from the Ae1-/- red cell membrane cannot be ruled out as an explanation for the reduced DIDS-sensitive anion conductance. PMID:18329299

VizieR Online Data Catalog: Equivalent width of 21 RR Lyrae stars (Pancino+, 2015)

NASA Astrophysics Data System (ADS)

Pancino, E.; Britavskiy, N.; Romano, D.; Cacciari, C.; Mucciarelli, A.; Clementini, G.

2015-02-01

Equivalent widths and atomic data of the absorption lines used in the abundance analysis, for each separate exposure at different phases. Observations of 15 RR Lyrae stars (DR And, X Ari, TW Boo, RZ Cam, RX Cet, U Com, RV CrB, SW CVn, UZ CVn, AE Dra, SZ Gem, VX Her, DH Hya, TU UMa, and RV UMa) and one BL Her star (UY Eri) were carried out with SARG@TNG, operated on the island of La Palma, Spain, during two separate runs in 2009 March and between September and November. Eight stars (SW Aqr, TW Cap, DH Hya, V Ind, SS Leo, V716 Oph, BK Tuc, and UV Vir) were observed with UVES@VLT, between 2009 April and August in service mode. (3 data files).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendigutía, I.; Brittain, S.; Eiroa, C.

This work presents X-Shooter/Very Large Telescope spectra of the prototypical, isolated Herbig Ae stars HD 31648 (MWC 480) and HD 163296 over five epochs separated by timescales ranging from days to months. Each spectrum spans over a wide wavelength range covering from 310 to 2475 nm. We have monitored the continuum excess in the Balmer region of the spectra and the luminosity of 12 ultraviolet, optical, and near-infrared spectral lines that are commonly used as accretion tracers for T Tauri stars. The observed strengths of the Balmer excesses have been reproduced from a magnetospheric accretion shock model, providing a meanmore » mass accretion rate of 1.11 × 10{sup –7} and 4.50 × 10{sup –7} M{sub ☉} yr{sup –1} for HD 31648 and HD 163296, respectively. Accretion rate variations are observed, being more pronounced for HD 31648 (up to 0.5 dex). However, from the comparison with previous results it is found that the accretion rate of HD 163296 has increased by more than 1 dex, on a timescale of ∼15 yr. Averaged accretion luminosities derived from the Balmer excess are consistent with the ones inferred from the empirical calibrations with the emission line luminosities, indicating that those can be extrapolated to HAe stars. In spite of that, the accretion rate variations do not generally coincide with those estimated from the line luminosities, suggesting that the empirical calibrations are not useful to accurately quantify accretion rate variability.« less

Genome-Wide Identification and Expression Analysis of the UGlcAE Gene Family in Tomato.

PubMed

Ding, Xing; Li, Jinhua; Pan, Yu; Zhang, Yue; Ni, Lei; Wang, Yaling; Zhang, Xingguo

2018-05-27

The UGlcAE has the capability of interconverting UDP-d-galacturonic acid and UDP-d-glucuronic acid, and UDP-d-galacturonic acid is an activated precursor for the synthesis of pectins in plants. In this study, we identified nine UGlcAE protein-encoding genes in tomato. The nine UGlcAE genes that were distributed on eight chromosomes in tomato, and the corresponding proteins contained one or two trans-membrane domains. The phylogenetic analysis showed that SlUGlcAE genes could be divided into seven groups, designated UGlcAE1 to UGlcAE6 , of which the UGlcAE2 were classified into two groups. Expression profile analysis revealed that the SlUGlcAE genes display diverse expression patterns in various tomato tissues. Selective pressure analysis indicated that all of the amino acid sites of SlUGlcAE proteins are undergoing purifying selection. Fifteen stress-, hormone-, and development-related elements were identified in the upstream regions (0.5 kb) of these SlUGlcAE genes. Furthermore, we investigated the expression patterns of SlUGlcAE genes in response to three hormones (indole-3-acetic acid (IAA), gibberellin (GA), and salicylic acid (SA)). We detected firmness, pectin contents, and expression levels of UGlcAE family genes during the development of tomato fruit. Here, we systematically summarize the general characteristics of the SlUGlcAE genes in tomato, which could provide a basis for further function studies of tomato UGlcAE genes.

Hot Gas Flows in T Tauri Stars

NASA Astrophysics Data System (ADS)

Ardila, David R.; Herczeg, G.; Gregory, S. G.; Ingleby, L.; France, K.; Brown, A.; Edwards, S.; Linsky, J.; Yang, H.; Valenti, J. A.; Johns-Krull, C. M.; Alexander, R.; Bergin, E. A.; Bethell, T.; Brown, J.; Calvet, N.; Espaillat, C.; Hervé, A.; Hillenbrand, L.; Hussain, G.; Roueff, E.; Schindhelm, E.; Walter, F. M.

2013-01-01

We describe observations of the hot gas 1e5 K) ultraviolet lines C IV and He II, in Classical and Weak T Tauri Stars (CTTSs, WTTSs). Our goal is to provide observational constraints for realistic models. Most of the data for this work comes from the Hubble proposal “The Disks, Accretion, and Outflows (DAO) of T Tau stars” (PI Herczeg). The DAO program is the largest and most sensitive high resolution spectroscopic survey of young stars in the UV ever undertaken and it provides a rich source of information for these objects. The sample of high resolution COS and STIS spectra presented here comprises 35 stars: one Herbig Ae star, 28 CTTSs, and 6 WTTSs. For CTTSs, the lines consist of two kinematic components. The relative strengths of the narrow and broad components (NC, BC) are similar in C IV but in He II the NC is stronger than the BC, and dominates the line profile. We do not find correlations between disk inclination and the velocity centroid, width, or shape of the CIV line profile. The NC of the C IV line in CTTSs increases in strength with accretion rate, and its contribution to the line increases from ˜20% to ˜80%, for the accretion rates considered here (1e-10 to 1e-7 Msun/yr). The CTTSs C IV lines are redshifted by ˜20 km/s while the CTTSs He II are redshifted by ˜10 km/s. Because the He II line and the C IV NC have the same width in CTTSs and in WTTSs, but are correlated with accretion, we suggest that they are produced in the stellar transition region. The accretion shock model predicts that the velocity of the post-shock emission should be 4x smaller than the velocity of the pre-shock emission. Identifying the post-shock emission with the NC and the pre-shock with the BC, we find that this is approximately the case in 11 out of 23 objects. The model cannot explain 11 systems in which the velocity of the NC is smaller than the velocity of the BC, or systems in which one of the velocities is negative (five CTTSs). The hot gas lines in some systems

Dust and gas around young stars

NASA Astrophysics Data System (ADS)

Chen, Christine Hsiao-Ching

To understand how asteroids, planets, and comets form in circumstellar disks of gas and dust, we have carried out a high resolution mid-infrared imaging study and a high resolution ultra violet spectroscopic study of the dust and gas around nearby pre-main sequence Herbig Ae stars and dusty main sequence stars. We have used the Keck I telescope to image at 11.7 μm and 17.9 μm the dust emission around ζ Lep, a main sequence A-type star with an infrared excess, 21.5 pc from the Sun. The excess is at most marginally resolved at 17.9 μm. The dust distance from the star is probably ≤6 AU, although some dust may extend to 9 AU. The mass of observed dust is ˜10 22 g. Since the lifetime of dust particles is about 104 yr because of the Poynting- Robertson effect, we robustly estimate at least 4 × 1026 g must reside in parent bodies which may be asteroids if the system is in a steady state and has an age of ˜300 Myr. This mass is approximately 200 times that contained within the main asteroid belt in our solar system. We have obtained FUSE spectra of σ Her, a nearby binary system, with a main sequence primary, that has a Vega-like infrared excess. We observe absorption in the excited fine structure lines C II* at 1037 Å, N II* at 1085 Å, and N II** at 1086 Å that are blueshifted by as much as ˜30 km/sec with respect to the star. Since these features are considerably narrower than the stellar lines and broader than interstellar features, the C II and N II are circumstellar. Since σ Her has a high luminosity, we suggest that there is a radiatively driven wind, arising from the circumstellar matter, rather than accretion as occurs around β Pic. Assuming that the gas is liberated by collisions between parent bodies at 20 AU, the approximate distance at which blackbody grains are in radiative equilibrium with the star and at which 3-body orbits become unstable, we infer dM/dt ˜6 × 10-12 M⊙ yr-1. This wind depletes the minimum mass of parent bodies in less than

AE 6: A model environment of trapped electrons for solar maximum

NASA Technical Reports Server (NTRS)

Teague, M. J.; Chan, K. W.; Vette, J. I.

1976-01-01

A projected inner zone electron model environment, AE 6, for the epoch 1980 is presented. It is intended to provide estimates of mission fluxes that spacecraft will encounter in the coming solar maximum years. AE 6 is presented by graphs of omnidirectional integral flux as a function of L shell, the ambient magnetic field B, and the energy E. Results of orbital integrations for altitudes from 150 n.m. to 18,000 n.m. are given for circular orbits with four different inclinations, using the AE 6 and the AE 4 solar maximum models for the inner and outer zones, respectively. The derivation of AE 6 is described, and a brief comparison is given of the radial profiles of equatorial fluxes from several related models. A short summary of the associated computer programs is included.

Applications of Advanced, Waveform Based AE Techniques for Testing Composite Materials

NASA Technical Reports Server (NTRS)

Prosser, William H.

1996-01-01

Advanced, waveform based acoustic emission (AE) techniques have been previously used to evaluate damage progression in laboratory tests of composite coupons. In these tests, broad band, high fidelity acoustic sensors were used to detect signals which were then digitized and stored for analysis. Analysis techniques were based on plate mode wave propagation characteristics. This approach, more recently referred to as Modal AE, provides an enhanced capability to discriminate and eliminate noise signals from those generated by damage mechanisms. This technique also allows much more precise source location than conventional, threshold crossing arrival time determination techniques. To apply Modal AE concepts to the interpretation of AE on larger composite structures, the effects of wave propagation over larger distances and through structural complexities must be well characterized and understood. In this research, measurements were made of the attenuation of the extensional and flexural plate mode components of broad band simulated AE signals in large composite panels. As these materials have applications in a cryogenic environment, the effects of cryogenic insulation on the attenuation of plate mode AE signals were also documented.

The flared inner disk of the Herbig Ae star AB Aurigae revealed by VLTI/MIDI in the N-band

NASA Astrophysics Data System (ADS)

di Folco, E.; Dutrey, A.; Chesneau, O.; Wolf, S.; Schegerer, A.; Leinert, Ch.; Lopez, B.

2009-06-01

Aims: We aim at using the long baselines of the VLT Interferometer and the mid-IR combiner MIDI (8-13 μm) to derive the morphology of the protoplanetary disk surrounding the Herbig Ae star AB Aurigae Methods: We present the first N-band analysis of AB Aur performed with a maximum angular resolution of 17 mas (2.5 AU at the Taurus-Auriga distance). We used the radiative transfer code MC3D and a silicate-dominated dust grain mixture to fit the spectral energy distribution (SED), together with the N-band dispersed visibilities (λ / δλ ~ 30) and to constrain the inner-disk spatial structure. Results: The silicate band is prominent in the ~ 300 mas FOV of the MIDI instrument, the emission reaches 70 to 90% of the total flux measured by ISO. The circumstellar emission (CSE) is resolved even at the shortest baselines. The spectrally dispersed visibilities show a steep drop between 8 and 9.5 μm, followed by a plateau between 10 and 13 μm. Our modelling shows that the observed SED and visibilities can be reproduced with a simple passive disk model. For such a weakly inclined disk (i ~ 30 deg), the mid-IR visibilities can directly determine the flaring index, while the scale height can be subsequently and unambiguously derived from the combination of the spectral and interferometric constraints. The modelling yields typical values for the scale height of about 8 AU at a radial distance of 100 AU and a flaring index in the range 1.25-1.30 for the explored range of model input parameters. Conclusions: The radial structure of the circumstellar inner disk around AB Aur is directly determined by MIDI. The radiative transfer modelling demonstrates the powerful synergy of interferometry and spectro-photometry to alleviate the degeneracy, which may hamper determining the disk morphology. Our analysis supports the classification of AB Aur among the flared disks of the first group in the Meeus classification. Based on observations collected at ESO (Paranal Observatory) with the

Request to monitor 2035-01 AE Aqr for multiwavelength campaign AND Reminder to monitor HT Cas, Z Cha, and OY Car

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2005-08-01

AAVSO Alert Notice 326 contains two topics. First: Dr. Christopher Mauche (Lawrence Livermore National Laboratory) has requested our assistance in monitoring the novalike intermediate polar AE Aqr in support of multiwavelength (gamma-ray, X-ray, UV, optical, and radio) observations scheduled for August-September 2005. AAVSO observations, particularly CCD ones, are requested to correlate with these multiwavelength observations; visual observations are also encouraged. Second: as announced in Alert Notice 317, Drs. Christopher Mauche, Peter Wheatley, and Koji Mukai have obtained time on XMM-Newton to observe HT Cas, Z Cha, or OY Car in outburst, and they have requested our assistance in monitoring these stars closely so we can inform them promptly when any of them go into outburst. Very prompt notification is essential because of the time required to trigger the satellite and the shortness of the outbursts of the target stars. Please monitor HT Cas, OY Car, and Z Cha closely from now through at least a month after the last observing window closes, and notify Headquarters immediately if any of the target stars goes into outburst. Both visual and CCD observations are encouraged. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

"Storms of crustal stress" and AE earthquake precursors

NASA Astrophysics Data System (ADS)

Gregori, G. P.; Poscolieri, M.; Paparo, G.; de Simone, S.; Rafanelli, C.; Ventrice, G.

2010-02-01

Acoustic emission (AE) displays violent paroxysms preceding strong earthquakes, observed within some large area (several hundred kilometres wide) around the epicentre. We call them "storms of crustal stress" or, briefly "crustal storms". A few case histories are discussed, all dealing with the Italian peninsula, and with the different behaviour shown by the AE records in the Cephalonia island (Greece), which is characterized by a different tectonic setting. AE is an effective tool for diagnosing the state of some wide slab of the Earth's crust, and for monitoring its evolution, by means of AE of different frequencies. The same effect ought to be detected being time-delayed, when referring to progressively lower frequencies. This results to be an effective check for validating the physical interpretation. Unlike a seismic event, which involves a much limited focal volume and therefore affects a restricted area on the Earth's surface, a "crustal storm" typically involves some large slab of lithosphere and crust. In general, it cannot be easily reckoned to any specific seismic event. An earthquake responds to strictly local rheological features of the crust, which are eventually activated, and become crucial, on the occasion of a "crustal storm". A "crustal storm" lasts typically few years, eventually involving several destructive earthquakes that hit at different times, at different sites, within that given lithospheric slab. Concerning the case histories that are here discussed, the lithospheric slab is identified with the Italian peninsula. During 1996-1997 a "crustal storm" was on, maybe elapsing until 2002 (we lack information for the period 1998-2001). Then, a quiet period occurred from 2002 until 26 May 2008, when a new "crustal storm" started, and by the end of 2009 it is still on. During the 1996-1997 "storm" two strong earthquakes occurred (Potenza and Colfiorito) - and (maybe) in 2002 also the Molise earthquake can be reckoned to this "storm". During the

The Gas Content Of Protoplanetary Herbig Ae/be Discs As Seen With Herschel

NASA Astrophysics Data System (ADS)

Meeus, Gwendolyn; Herschel OTKP, GASPS; Dent, B.

2011-09-01

The mechanisms determining planet formation are not (yet) well-understood. Primordial protoplanetary discs consist 99% out of gas, and only 1% out of dust. With time, those discs are believed to evolve from a flaring geometry into a flat geometry, as the initially small dust grains grow to larger sizes and settle towards the mid-plane. In the mean time, the gas will disperse, until so little is left that giant planets no longer can form. As an important piece of the puzzle of planet formation, it is important to understand the influence of the gas heating/cooling processes on the young disc structure, its chemical composition and finally how fast gas gets dispersed. In this talk, we study the protoplanetary discs around Herbig Ae/Be stars, young objects of intermediate mass, in the context of its gas content. We present Herschel PACS spectroscopic observations for a sample that was obtained within the GASPS (Gas in Protoplanetary Systems) Open Time Key Project, concentrating on the detection and characterisation of emission lines of the [OI], [CII], and CO, tracing the disc between 5 and 500 AU. We look for correlations between the observed line fluxes and stellar properties such as effective temperature, Halpha emission, accretion rates and UV flux, as well as the disc properties: degree of flaring, presence and strength of PAH emission and disc mass. We will present a few cases to show how simultaneous modeling (using the thermo-chemical disc code ProDiMo) of the atomic fine structure lines and both molecular lines can constrain the disc gas mass, once the disc structure is derived. Finally, we compare our gas line observations with those of young debris disc stars, for which the HAEBE stars are thought to be progenitors.

Management of alcohol misuse in Scotland: the role of A&E nurses.

PubMed

Anderson, S; Eadie, D R; MacKintosh, A M; Haw, S

2001-04-01

Despite national targets to reduce excessive drinking in Scotland, rates have increased dramatically since the mid-eighties. The role of Accident and Emergency (A&E) departments in the management of alcohol misuse is much debated. This postal survey was conducted with senior medical and nursing staff in A&E departments and minor injury units throughout Scotland to examine the prevalence of alcohol-related attendances and staff's attitudes towards identifying and responding to alcohol-related attendances. A 57% response rate was achieved, representing 87% of all A&E institutions in Scotland (n = 84). The results reveal an estimated 1 in 7 attendances in A&E in Scotland are alcohol-related, and 1 in 5 of these result in admission. However, over two-fifths of departments do not routinely screen for, or keep records of, patients who attend with alcohol problems. Intervention is normally limited to a brief dialogue and referral to the patient's GP. Despite considerable barriers, A&E nursing staff express a willingness to assume a preventive role, but acknowledge lack of appropriate training and sources of support. It is concluded that there is scope for developing identification and brief intervention services within A&E. However, such developments are dependent upon alcohol issues assuming a higher priority among senior A&E staff.

Ae2Sb2X4F2 (Ae = Sr, Ba): new members of the homologous series Ae2M(1+n)X(3+n)F2 designed from rock salt and fluorite 2D building blocks.

PubMed

Kabbour, Houria; Cario, Laurent

2006-03-20

We have designed new compounds within the homologous series Ae2F2M(1+n)X(3+n) (Ae = Sr, Ba; M = main group metal; n = integer) built up from the stacking of 2D building blocks of rock salt and fluorite types. By incrementally increasing the size of the rock salt 2D building blocks, we have obtained two new n = 1 members of this homologous series, namely, Sr2F2Sb2Se4 and Ba2F2Sb2Se4. We then succeeded in synthesizing these compounds using a high-temperature ceramic method. The structure refinements from the powder or single-crystal X-ray diffraction data confirmed presence of the expected alternating stacking of fluorite [Ae2F2] (Ae = Sr, Ba) and rock salt [Sb2Se4] 2D building blocks. However the Ba derivative shows a strong distortion of the [Sb2Se4] block and a concomitant change of the Sb atom coordination likely related to the lone-pair activity.

Phylodynamic analysis of the dissemination of HIV-1 CRF01_AE in Vietnam.

PubMed

Liao, Huanan; Tee, Kok Keng; Hase, Saiki; Uenishi, Rie; Li, Xiao-Jie; Kusagawa, Shigeru; Thang, Pham Hong; Hien, Nguyen Tran; Pybus, Oliver G; Takebe, Yutaka

2009-08-15

To estimate the epidemic history of HIV-1 CRF01_AE in Vietnam and adjacent Guangxi, China, we determined near full-length nucleotide sequences of CRF01_AE from a total of 33 specimens collected in 1997-1998 from different geographic regions and risk populations in Vietnam. Phylogenetic and Bayesian molecular clock analyses were performed to estimate the date of origin of CRF01_AE lineages. Our study reconstructs the timescale of CRF01_AE expansion in Vietnam and neighboring regions and suggests that the series of CRF01_AE epidemics in Vietnam arose by the sequential introduction of founder strains into new locations and risk groups. CRF01_AE appears to have been present among heterosexuals in South-Vietnam for more than a decade prior to its epidemic spread in the early 1990s. In the late 1980s, the virus spread to IDUs in Southern Vietnam and subsequently in the mid-1990s to IDUs further north. Our results indicate the northward dissemination of CRF01_AE during this time.

OPTICAL SPECTROSCOPY OF X-RAY-SELECTED YOUNG STARS IN THE CARINA NEBULA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vaidya, Kaushar; Chen, Wen-Ping; Lee, Hsu-Tai

We present low-resolution optical spectra for 29 X-ray sources identified as either massive star candidates or low-mass pre-main-sequence (PMS) star candidates in the clusters Trumpler 16 and Trumpler 14 of the Carina Nebula. Spectra of two more objects (one with an X-ray counterpart, and one with no X-ray counterpart), not originally our targets, but found close (∼3″) to two of our targets, are presented as well. Twenty early-type stars, including an O8 star, seven B1–B2 stars, two B3 stars, a B5 star, and nine emission-line stars, are identified. Eleven T Tauri stars, including eight classical T Tauri stars (CTTSs) and threemore » weak-lined T Tauri stars, are identified. The early-type stars in our sample are more reddened compared to the previously known OB stars of the region. The Chandra hardness ratios of our T Tauri stars are found to be consistent with the Chandra hardness ratios of T Tauri stars of the Orion Nebula Cluster. Most early-type stars are found to be nonvariable in X-ray emission, except the B2 star J104518.81–594217.9, the B3 star J104507.84–594134.0, and the Ae star J104424.76–594555.0, which are possible X-ray variables. J104452.20–594155.1, a CTTS, is among the brightest and the hardest X-ray sources in our sample, appears to be a variable, and shows a strong X-ray flare. The mean optical and near-infrared photometric variability in the V and K{sub s} bands, of all sources, is found to be ∼0.04 and 0.05 mag, respectively. The T Tauri stars show significantly larger mean variation, ∼0.1 mag, in the K{sub s} band. The addition of one O star and seven B1–B2 stars reported here contributes to an 11% increase of the known OB population in the observed field. The 11 T Tauri stars are the first ever confirmed low-mass PMS stars in the Carina Nebula region.« less

Application of TURBO-AE to Flutter Prediction: Aeroelastic Code Development

NASA Technical Reports Server (NTRS)

Hoyniak, Daniel; Simons, Todd A.; Stefko, George (Technical Monitor)

2001-01-01

The TURBO-AE program has been evaluated by comparing the obtained results to cascade rig data and to prediction made from various in-house programs. A high-speed fan cascade, a turbine cascade, a turbine cascade and a fan geometry that shower flutter in torsion mode were analyzed. The steady predictions for the high-speed fan cascade showed the TURBO-AE predictions to match in-house codes. However, the predictions did not match the measured blade surface data. Other researchers also reported similar disagreement with these data set. Unsteady runs for the fan configuration were not successful using TURBO-AE .

Propagation of Flexural Mode AE Signals in GR/EP Composite Plates

NASA Technical Reports Server (NTRS)

Prosser, W. H.; Gorman, M. R.

1992-01-01

It has been documented that AE signals propagate in thin plates as extensional and flexural plate modes. This was demonstrated using simulated AE sources (pencil lead breaks) by Gorman on thin aluminum and gr/ep composite plates and by Gorman and Prosser on thin aluminum plates. A typical signal from a pencil lead break source which identifies these two modes is shown. AE signals from transverse matrix cracking sources in gr/ep composite plates were also shown to propagate as plate modes by Gorman and Ziola. Smith showed that crack growth events in thin aluminum plates under spectrum fatigue loading produced signals that propagated as plate modes. Additionally, Prosser et al. showed that AE signals propagated as plate modes in a thin walled composite tube.

Time studies in A&E departments--a useful tool for management.

PubMed

Aharonson-Daniel, L; Fung, H; Hedley, A J

1996-01-01

A time and motion study was conducted in an accident and emergency (A&E) department in a Hong Kong Government hospital in order to suggest solutions for severe queuing problems found in A&E. The study provided useful information about the patterns of arrival and service; the throughput; and the factors that influence the length of the queue at the A&E department. Plans for building a computerized simulation model were dropped as new intelligence generated by the study enabled problem solving using simple statistical analysis and common sense. Demonstrates some potential benefits for management in applying operations research methods in busy clinical working environments. The implementation of the recommendations made by this study successfully eliminated queues in A&E.

Hot Gas Lines in T Tauri Stars

NASA Astrophysics Data System (ADS)

Ardila, David R.; Herczeg, Gregory J.; Gregory, Scott G.; Ingleby, Laura; France, Kevin; Brown, Alexander; Edwards, Suzan; Johns-Krull, Christopher; Linsky, Jeffrey L.; Yang, Hao; Valenti, Jeff A.; Abgrall, Hervé; Alexander, Richard D.; Bergin, Edwin; Bethell, Thomas; Brown, Joanna M.; Calvet, Nuria; Espaillat, Catherine; Hillenbrand, Lynne A.; Hussain, Gaitee; Roueff, Evelyne; Schindhelm, Eric R.; Walter, Frederick M.

2013-07-01

For Classical T Tauri Stars (CTTSs), the resonance doublets of N V, Si IV, and C IV, as well as the He II 1640 Å line, trace hot gas flows and act as diagnostics of the accretion process. In this paper we assemble a large high-resolution, high-sensitivity data set of these lines in CTTSs and Weak T Tauri Stars (WTTSs). The sample comprises 35 stars: 1 Herbig Ae star, 28 CTTSs, and 6 WTTSs. We find that the C IV, Si IV, and N V lines in CTTSs all have similar shapes. We decompose the C IV and He II lines into broad and narrow Gaussian components (BC and NC). The most common (50%) C IV line morphology in CTTSs is that of a low-velocity NC together with a redshifted BC. For CTTSs, a strong BC is the result of the accretion process. The contribution fraction of the NC to the C IV line flux in CTTSs increases with accretion rate, from ~20% to up to ~80%. The velocity centroids of the BCs and NCs are such that V BC >~ 4 V NC, consistent with the predictions of the accretion shock model, in at most 12 out of 22 CTTSs. We do not find evidence of the post-shock becoming buried in the stellar photosphere due to the pressure of the accretion flow. The He II CTTSs lines are generally symmetric and narrow, with FWHM and redshifts comparable to those of WTTSs. They are less redshifted than the CTTSs C IV lines, by ~10 km s-1. The amount of flux in the BC of the He II line is small compared to that of the C IV line, and we show that this is consistent with models of the pre-shock column emission. Overall, the observations are consistent with the presence of multiple accretion columns with different densities or with accretion models that predict a slow-moving, low-density region in the periphery of the accretion column. For HN Tau A and RW Aur A, most of the C IV line is blueshifted suggesting that the C IV emission is produced by shocks within outflow jets. In our sample, the Herbig Ae star DX Cha is the only object for which we find a P-Cygni profile in the C IV line, which

Suppression of RND3 activity by AES downregulation promotes cancer cell proliferation and invasion.

PubMed

Xia, Hongwei; Li, Mingxing; Chen, Liang; Leng, Weibing; Yuan, Dandan; Pang, Xiaohui; Chen, Liu; Li, Ronghui; Tang, Qiulin; Bi, Feng

2013-05-01

Amino-terminal enhancer of split (AES) is a member of the Groucho/TLE family. Although it has no DNA-binding site, AES can regulate transcriptional activity by interacting with transcriptional factors. Emerging evidence indicates that AES may play an important role in tumor metastasis, but the molecular mechanism is still poorly understood. In this study, we found that knockdown of AES by RNA interference (RNAi) downregulated RND3 expression at the mRNA and protein levels in MDA-MB-231 and HepG2, two cancer cell lines. Furthermore, luciferase assays showed that overexpression of AES significantly enhanced RND3 promoter activity. Moreover, inhibition of AES both in MDA-MB-231 and HepG2 cells by RNAi significantly promoted cell proliferation, cell cycle progression and invasion, consistent with the effects of RNAi-mediated RND3 knockdown in these cells. For the first time, data are presented showing that alteration of the malignant behavior of cancer cells by AES is related to RND3 regulation, and these findings also provide new insights into the mechanism of AES action in regulating tumor malignancy.

Immortalization of human AE pre-leukemia cells by hTERT allows leukemic transformation

PubMed Central

Wunderlich, Mark; Chou, Fu-Sheng; Mulloy, James C.

2016-01-01

Human CD34+ hematopoietic stem and progenitor cells (HSPC) expressing fusion protein AML1-ETO (AE), generated by the t(8;21)(q22;q22) rearrangement, manifest enhanced self-renewal and dysregulated differentiation without leukemic transformation, representing a pre-leukemia stage. Enabling replicative immortalization via telomerase reactivation is a crucial step in cancer development. However, AE expression alone is not sufficient to maintain high telomerase activity to immortalize human HSPC cells, which may hamper transformation. Here, we investigated the cooperativity of telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase, and AE in disease progression. Enforced expression of hTERT immortalized human AE pre-leukemia cells in a telomere-lengthening independent manner, and improved the pre-leukemia stem cell function by enhancing cell proliferation and survival. AE-hTERT cells retained cytokine dependency and multi-lineage differentiation potential similar to parental AE clones. Over the short-term, AE-hTERT cells did not show features of stepwise transformation, with no leukemogenecity evident upon initial injection into immunodeficient mice. Strikingly, after extended culture, we observed full transformation of one AE-hTERT clone, which recapitulated the disease evolution process in patients and emphasizes the importance of acquiring cooperating mutations in t(8;21) AML leukemogenesis. In summary, achieving unlimited proliferative potential via hTERT activation, and thereby allowing for acquisition of additional mutations, is a critical link for transition from pre-leukemia to overt disease in human cells. AE-hTERT cells represent a tractable model to study cooperating genetic lesions important for t(8;21) AML disease progression. PMID:27509060

Structural and mutational analyses of Aes, an inhibitor of MalT in Escherichia coli.

PubMed

Schiefner, André; Gerber, Kinga; Brosig, Alexander; Boos, Winfried

2014-02-01

The acyl esterase Aes effectively inhibits the transcriptional activity of MalT-the central activator of maltose and maltodextrin utilizing genes in Escherichia coli. To provide better insight into the nature of the interaction between Aes and MalT, we determined two different crystal structures of Aes-in its native form and covalently modified by a phenylmethylsulfonyl moiety at its active site serine. Both structures show distinct space groups and were refined to a resolution of 1.8 Å and 2.3 Å, respectively. The overall structure of Aes resembles a canonical α/β-hydrolase fold, which is extended by a funnel-like cap structure that forms the substrate-binding site. The catalytic triad of Aes, comprising residues Ser165, His292, and Asp262, is located at the bottom of this funnel. Analysis of the crystal-packing contacts of the two different space groups as well as analytical size-exclusion chromatography revealed a homodimeric arrangement of Aes. The Aes dimer adopts an antiparallel contact involving both the hydrolase core and the cap, with its twofold axis perpendicular to the largest dimension of Aes. To identify the surface area of Aes that is responsible for the interaction with MalT, we performed a structure-based alanine-scanning mutagenesis to pinpoint Aes residues that are significantly impaired in MalT inhibition, but still exhibit wild-type expression and enzymatic activity. These residues map to a shallow slightly concave surface patch of Aes at the opposite site of the dimerization interface and indicate the surface area that interacts with MalT. Copyright © 2013 Wiley Periodicals, Inc.

Mechanisms of Diagonal-Shear Failure in Reinforced Concrete Beams analyzed by AE-SiGMA

NASA Astrophysics Data System (ADS)

Ohno, Kentaro; Shimozono, Shinichiro; Sawada, Yosuke; Ohtsu, Masayasu

Serious shear failures in reinforced concrete (RC) structures were reported in the Hanshin-Awaji Earthquake. In particular, it was demonstrated that a diagonal-shear failure could lead to disastrous damage. However, mechanisms of the diagonal-shear failure in RC beams have not been completely clarified yet. In this study, the diagonal-shear failure in RC beams is investigated, applying acoustic emission (AE) method. To identify source mechanisms of AE signals, SiGMA (Simplified Green's functions for Moment tensor Analysis) procedure was applied. Prior to four-point bending tests of RC beams, theoretical waveforms were calculated to determine the optimal arrangement of AE sensors. Then, cracking mechanisms in experiments were investigated by applying the SiGMA procedure to AE waveforms. From results of the SiGMA analysis, dominant motions of micro-cracks are found to be of shear crack in all the loading stages. As the load increased, the number of tensile cracks increased and eventually the diagonal-shear failure occurred in the shear span. Prior to final failure, AE cluster of micro-cracks was intensely observed in the shear span. To classify AE sources into tensile and shear cracks, AE parameter analysis was also applied. As a result, most of AE hits are classified into tensile cracks. The difference between results obtained by the AE parameter analysis and by the SiGMA analysis is investigated and discussed.

AE8/AP8 Implementations in AE9/AP9, IRBEM, and SPENVIS

DTIC Science & Technology

2014-02-18

period applies to orbit generation only; AE8/AP8 utilizes geomagnetic field models from other epochs as specified in the table below.) SHIELDOSE2 model...finite and semi- infinite slab data tables for Bremsstrahlung have been reversed [Heynderickx, private communication, May 2013]. This correction is...Cain, J. C., S. J. Hendricks, R. A. Langel, and W. V. Hudson (1967), A proposed model for the international geomagnetic reference field, 1965, J

Molecular epidemiological study of HIV-1 CRF01_AE transmission in Hong Kong.

PubMed

Chen, J H K; Wong, K H; Li, P; Chan, K C; Lee, M P; Lam, H Y; Cheng, V C C; Yuen, K Y; Yam, W C

2009-08-15

The objective of this study was to investigate the transmission history of the HIV-1 CRF01_AE epidemics in Hong Kong between 1994 and 2007. A total of 465 HIV-1 CRF01_AE pol sequences were derived from an in-house or a commercial HIV-1 genotyping system. Phylogenies of CRF01_AE sequences were analyzed by the Bayesian coalescent method. CRF01_AE patient population included 363 males (78.1%) and 102 females (21.9%), whereas 65% (314 of 465) were local Chinese. Major transmission routes were heterosexual contact (63%), followed by intravenous drug use (IDU) (19%) and men having sex with men (MSM) (17%). From phylogenetic analysis, local CRF01_AE strains were from multiple origins with 3 separate transmission clusters identified. Cluster 1 consisted mainly of Chinese male IDUs and heterosexuals. Clusters 2 and 3 included mainly local Chinese MSM and non-Chinese Asian IDUs, respectively. Chinese reference isolates available from China (Fujian, Guangxi, or Liaoning) were clonally related to our transmission clusters, demonstrating the epidemiological linkage of CRF01_AE infections between Hong Kong and China. The 3 individual local transmission clusters were estimated to have initiated since late 1980s and late 1990s, causing subsequent epidemics in the early 2000s. This is the first comprehensive molecular epidemiological study of HIV-1 CRF01_AE in Hong Kong. It revealed that MSM contact is becoming a major route of local CRF01_AE transmission in Hong Kong. Epidemiological linkage of CRF01_AE between Hong Kong and China observed in this study indicates the importance of regular molecular epidemiological surveillance for the HIV-1 epidemic in our region.

AES Water Architecture Study Interim Results

NASA Technical Reports Server (NTRS)

Sarguisingh, Miriam J.

2012-01-01

The mission of the Advanced Exploration System (AES) Water Recovery Project (WRP) is to develop advanced water recovery systems in order to enable NASA human exploration missions beyond low earth orbit (LEO). The primary objective of the AES WRP is to develop water recovery technologies critical to near term missions beyond LEO. The secondary objective is to continue to advance mid-readiness level technologies to support future NASA missions. An effort is being undertaken to establish the architecture for the AES Water Recovery System (WRS) that meets both near and long term objectives. The resultant architecture will be used to guide future technical planning, establish a baseline development roadmap for technology infusion, and establish baseline assumptions for integrated ground and on-orbit environmental control and life support systems (ECLSS) definition. This study is being performed in three phases. Phase I of this study established the scope of the study through definition of the mission requirements and constraints, as well as indentifying all possible WRS configurations that meet the mission requirements. Phase II of this study focused on the near term space exploration objectives by establishing an ISS-derived reference schematic for long-duration (>180 day) in-space habitation. Phase III will focus on the long term space exploration objectives, trading the viable WRS configurations identified in Phase I to identify the ideal exploration WRS. The results of Phases I and II are discussed in this paper.

Clinical decision support tools in A&E nursing: a preliminary study.

PubMed

New, T D

This article describes how a large trust in the north east of England is in the process of developing a unique service for non-emergency patients in one of its main A&E departments. The Urgent Need Assessment Service (UNAS), co-located within the main A&E department, features the use of NHS Direct computerised algorithms to enable nurses to recommend the best treatment or course of action accurately and safely, for all patients attending the department who are categorised as blue or green status in accordance with the Manchester triage model of A&E assessment. The UNAS facility incorporates discretely staffed minor injuries and minor ailments services. UNAS assessment nurses are specially trained to use their A&E experience, together with the computer model, and to make an assessment in partnership with the patient, sharing information displayed on the computer screen and working together to reach a jointly agreed treatment plan or outcome. The UNAS pilot and evaluation commenced in September 1999 and results and outcomes are presented for the period from September 3 to December 31 2000. Approximately 75 per cent of all A&E attenders are given blue or green status. UNAS has led to faster treatment and reduced waiting times for these people, increasing patient satisfaction while enabling the A&E department to concentrate its resources on treating more serious cases. This pilot study has proved to be highly satisfactory to the majority of people who have been treated at UNAS. Those previously regarded as 'inappropriate attenders' might be better suited to treatment in a different department, separate from the traditional A&E department, with reduced waiting times, and under the care of specially trained nurses.

Ae Behavior of Smart Stress Memory Patch after Variable Amplitude Loading

NASA Astrophysics Data System (ADS)

Fujino, Y.; Nambu, S.; Enoki, M.

Recently, the structural health monitoring becomes increasingly great important to assure the ease and safety of our life, and it is required significantly to develop non-destructive evaluation for structures such as bridges and tunnels. Some sacrificed specimens have been developed to evaluate the fatigue damage of structures such as fatigue cycles and residual lifetime, but it can be applied only when the stress history is known beforehand. These fatigue sensors need no cable and can be used at low cost in contrast to strain gage. In previous study, a smart stress memory patch was developed as a new fatigue sensor. The patch can measure simultaneously the maximum stress, stress amplitude and the number of fatigue cycles by crack length measurement and Kaiser effect of Acoustic Emission (AE). The crack growth behavior under constant amplitude (CA) loading has been investigated, and AE behavior also has been evaluated only after CA loading. However, AE characteristics after variable amplitude (VA) loading in service are extremely important. Moreover, it is very important to control AE behavior of the smart patch in order to evaluate the applied stress using Kaiser effect. In this study, fatigue test with single overload was investigated to evaluate its influence. Moreover, effect of crack length and heat treatment on AE behavior was also investigated. Finally, AE behavior of the patch was evaluated after fatigue CA loading with overload or VA loading with log-normal distribution and overload.

Transitional Disks Associated with Intermediate-Mass Stars: Results of the SEEDS YSO Survey

NASA Technical Reports Server (NTRS)

Grady, C.; Fukagawa, M.; Maruta, Y.; Ohta, Y.; Wisniewski, J.; Hashimoto, J.; Okamoto, Y.; Momose, M.; Currie, T.; McElwain, M.;

Applying transpose matrix on advanced encryption standard (AES) for database content

NASA Astrophysics Data System (ADS)

Manurung, E. B. P.; Sitompul, O. S.; Suherman

2018-03-01

Advanced Encryption Standard (AES) is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) and has been adopted by the U.S. government and is now used worldwide. This paper reports the impact of transpose matrix integration to AES. Transpose matrix implementation on AES is aimed at first stage of chypertext modifications for text based database security so that the confidentiality improves. The matrix is also able to increase the avalanche effect of the cryptography algorithm 4% in average.

Optimization of DIII-D discharges to avoid AE destabilization

NASA Astrophysics Data System (ADS)

Varela, Jacobo; Spong, Donald; Garcia, Luis; Huang, Juan; Murakami, Masanori

2017-10-01

The aim of the study is to analyze the stability of Alfven Eigenmodes (AE) perturbed by energetic particles (EP) during DIII-D operation. We identify the optimal NBI operational regimes that avoid or minimize the negative effects of AE on the device performance. We use the reduced MHD equations to describe the linear evolution of the poloidal flux and the toroidal component of the vorticity in a full 3D system, coupled with equations of density and parallel velocity moments for the energetic particles, including the effect of the acoustic modes. We add the Landau damping and resonant destabilization effects using a closure relation. We perform parametric studies of the MHD and AE stability, taking into account the experimental profiles of the thermal plasma and EP, also using a range of values of the energetic particles β, density and velocity as well the effect of the toroidal couplings. We reproduce the AE activity observed in high poloidal β discharge at the pedestal and reverse shear discharges. This material based on work is supported both by the U.S. Department of Energy, Office of Science, under Contract DE-AC05-00OR22725 with UT-Battelle, LLC. Research sponsored in part by the Ministerio de Economia y Competitividad of Spain under the project.

Secure Multiparty AES

NASA Astrophysics Data System (ADS)

Damgård, Ivan; Keller, Marcel

We propose several variants of a secure multiparty computation protocol for AES encryption. The best variant requires 2200 + {{400}over{255}} expected elementary operations in expected 70 + {{20}over{255}} rounds to encrypt one 128-bit block with a 128-bit key. We implemented the variants using VIFF, a software framework for implementing secure multiparty computation (MPC). Tests with three players (passive security against at most one corrupted player) in a local network showed that one block can be encrypted in 2 seconds. We also argue that this result could be improved by an optimized implementation.

A high performance hardware implementation image encryption with AES algorithm

NASA Astrophysics Data System (ADS)

Farmani, Ali; Jafari, Mohamad; Miremadi, Seyed Sohrab

2011-06-01

This paper describes implementation of a high-speed encryption algorithm with high throughput for encrypting the image. Therefore, we select a highly secured symmetric key encryption algorithm AES(Advanced Encryption Standard), in order to increase the speed and throughput using pipeline technique in four stages, control unit based on logic gates, optimal design of multiplier blocks in mixcolumn phase and simultaneous production keys and rounds. Such procedure makes AES suitable for fast image encryption. Implementation of a 128-bit AES on FPGA of Altra company has been done and the results are as follow: throughput, 6 Gbps in 471MHz. The time of encrypting in tested image with 32*32 size is 1.15ms.

Synthesis, Crystal and Electronic Structures of the Pnictides AE 3TrPn 3 (AE = Sr, Ba; Tr = Al, Ga; Pn = P, As)

DOE PAGES

Stoyko, Stanislav; Voss, Leonard; He, Hua; ...

2015-09-24

New ternary arsenides AE 3TrAs 3 (AE = Sr, Ba; Tr = Al, Ga) and their phosphide analogs Sr 3GaP 3 and Ba 3AlP 3 have been prepared by reactions of the respective elements at high temperatures. Single-crystal X-ray diffraction studies reveal that Sr 3AlAs 3 and Ba 3AlAs 3 adopt the Ba 3AlSb 3-type structure (Pearson symbol oC56, space group Cmce, Z = 8). This structure is also realized for Sr 3GaP 3 and Ba 3AlP 3. Likewise, the compounds Sr 3GaAs 3 and Ba 3GaAs 3 crystallize with the Ba 3GaSb 3-type structure (Pearson symbol oP56, space groupmore » Pnma, Z = 8). Both structures are made up of isolated pairs of edge-shared AlPn 4 and GaPn 4 tetrahedra (Pn = pnictogen, i.e., P or As), separated by the alkaline-earth Sr 2+ and Ba 2+ cations. In both cases, there are no homoatomic bonds, hence, regardless of the slightly different atomic arrangements, both structures can be rationalized as valence-precise [AE 2+] 3[Tr 3+][Pn 3-] 3, or rather [AE 2+] 6[Tr 2Pn 6] 12-, i.e., as Zintl phases.« less

AES/GRG5: more than just a dominant-negative TLE/GRG family member.

PubMed

Beagle, Brandon; Johnson, Gail V W

2010-11-01

The human Transducin-like Enhancer of Split (TLE) and mouse homologue, Groucho gene-related protein (GRG), represent a family of conserved non-DNA binding transcriptional modulatory proteins divided into two subgroups based upon size. The long TLE/GRGs consist of four pentadomain proteins that are dedicated co-repressors for multiple transcription factors (TF). The second TLE/GRG subgroup is composed of the Amino-terminal Enhancer of Split (AES) in humans and its mouse homolog GRG5 (AES/GRG5). In contrast to the dedicated co-repressor function of long TLE/GRGs, AES/GRG5 can both positively or negatively modulate various TF as well as non-TF proteins in a long TLE/GRG-dependent or -independent manner. Therefore, AES/GRG5 is a functionally dynamic protein that is not exclusively defined by its role as a long TLE/GRG antagonist. AES/GRG5 may function in various developmental and pathological processes but the functional characteristics of endogenous AES/GRG5 in a physiologically relevant context remains to be determined. © 2010 Wiley-Liss, Inc.

A STAR-FORMING RING AROUND κ Ori 250 pc FROM THE SUN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pillitteri, I.; Wolk, S. J.; Megeath, S. T., E-mail: ipillitt@cfa.harvard.edu

2016-04-01

X-rays are a powerful probe of activity in early stages of star formation. They allow us to identify young stars even after they have lost the IR signatures of circumstellar disks and provide constraints on their distance. Here, we report on XMM-Newton observations that detect 121 young stellar objects (YSOs) in two fields between L1641 S and κ Ori. These observations extend the Survey of Orion A with XMM and Spitzer (SOXS). The YSOs are contained in a ring of gas and dust apparent at millimeter wavelengths, and in far-IR and near-IR surveys. The X-ray luminosity function of the YSOs detectedmore » in the two fields indicates a distance of 250–280 pc, much closer than the Orion A cloud and similar to distance estimates of κ Ori. We propose that the ring is a 5–8 pc diameter shell that has been swept up by κ Ori. This ring contains several groups of stars detected by Spitzer and WISE including one surrounding the Herbig Ae/Be stars V1818 Ori. In this interpretation, the κ Ori ring is one of several shells swept up by massive stars within the Orion Eridanus Superbubble and is unrelated to the southern portion of Orion A/L1641 S.« less

The association of Aedes aegypti and Ae. albopictus in Allende, Nuevo León, Mexico.

PubMed

Mercado-Hernandez, Roberto; Aguilar-Gueta, Juan de Dios; Fernandez-Salas, Ildefoso; Earl, Paul R

2006-03-01

The recent appearance of Aedes Stegomyia albopictus (Skuse) in Nuevo León (NL) worries health officials. It is a vector of dengue fever in Asia and is more resistant to lower temperatures than Ae. aegypti. The objective of this study was to learn about some ecological parameters of Ae. albopictus and their association with Ae. aegypti, and other culicids in Allende, NL, Mexico, during 1999. Allende is a small town close to metropolitan Monterrey, which has 4 million inhabitants. The design was random with monthly sampling of 175 ovitraps. Chi-square analyses were performed with data of presence, absence, frequency, and relative abundances. During the study, the species Culex tarsalis (Coquillet), Cx. thriambus (Dyar), Cx. pipiens (Linnaeus), Cx. coronator (Dyar and Knab), Ae. albopictus, Ae. aegypti, Toxorhynchites rutilus (Coquillet), and Ae. triseriatus (Say) were found. April is the month for large numbers of mosquito species. September had the highest populations in positive ovitraps (66.67%), followed by July (63.27% of traps). Aedes aegypti was the most abundant (65.13%), followed by Ae. albopictus (19.71%). Both Ae. albopictus and Ae. aegypti were found from April until December. Aedes aegypti was more abundant than Ae. albopictus, except in August, when they were similar (chi2 = 0.197, P < 0.05). We found significant association between the presence of both species for every study month (chi2 = 9.837, P < 0.05), with a contingency coefficient of 0.247. September and November were the months having the most mosquitoes in this association. Only considering Ae. albopictus, more were found in ovitraps in July (34.6%), followed by September (33.3%). However, its presence was not significant throughout the year. Of 2 zones, in town and at the river, prevalence indicated that Ae. albopictus preferred the river. This mosquito is in its establishment phase in this area and requires further studies.

/ae/ versus /?/: Vowel Fossilization in the Pronunciation of Turkish English Majors: Rehabilitation 1

ERIC Educational Resources Information Center

Demirezen, Mehmet

2017-01-01

In North American English (NAE) and British English, [ae] and [?] are open vowel phonemes which are articulated by a speaker easily without a build-up of air pressure. Among all English vowels, the greatest problem for most Turkish majors of English is the discrimination of [ae] and [?]. In English, [ae] is called the "short a" or ash,…

Histone deacetylase-related protein inhibits AES-mediated neuronal cell death by direct interaction.

PubMed

Zhang, Xiaoguang; Chen, Hsin-Mei; Jaramillo, Eduardo; Wang, Lulu; D'Mello, Santosh R

2008-08-15

Histone deacetylase-related protein (HDRP), an alternatively spliced and truncated form of histone deacetylase-9 that lacks a C-terminal catalytic domain, protects neurons from death. In an effort to understand the mechanism by which HDRP mediates its neuroprotective effect, we screened for proteins in the brain that interact with HDRP by using a yeast two-hybrid assay. One of the HDRP-interacting proteins identified in this screen was amino enhancer of split (AES), a 197-amino acid protein belonging to the Groucho family. Interaction between HDRP and AES was verified by in vitro binding assays, coimmunoprecipitation, and colocalization studies. To investigate the significance of the HDRP-AES association to the regulation of neuronal survival, we used cultured cerebellar granule neurons, which undergo apoptosis when treated with low potassium (LK) medium. We found that in contrast to HDRP, whose expression is markedly reduced by LK treatment, AES expression was not appreciably altered. Forced expression of AES in healthy neurons results in cell death, an action that is blocked by the coexpression of HDRP. AES is a truncated version of larger Groucho-related proteins, one of which is transducin-like enhancer of split (TLE)-1. We found that the expression of TLE1 is reduced in LK-treated neurons and the forced expression of TLE1 blocks LK-induced neuronal death as well as death induced by AES. Our results show that AES has apoptotic activity in neurons and suggest that neuroprotection by HDRP is mediated by the inhibition of this activity through direct interaction.

Genetic effect of the Aegilops caudata plasmon on the manifestation of the Ae. cylindrica genome.

PubMed

Tsunewaki, Koichiro; Mori, Naoki; Takumi, Shigeo

2014-01-01

In the course of reconstructing Aegilops caudata from its own genome (CC) and its plasmon, which had passed half a century in common wheat (genome AABBDD), we produced alloplasmic Ae. cylindrica (genome CCDD) with the plasmon of Ae. caudata. This line, designated (caudata)-CCDD, was found to express male sterility in its second substitution backcross generation (SB2) of (caudata)-AABBCCDD pollinated three times with the Ae. cylindrica pollen. We repeatedly backcrossed these SB2 plants with the Ae. cylindrica pollen until the SB5 generation, and SB5F2 progeny were produced by self-pollination of the SB5 plants. Thirteen morphological and physiological characters, including pollen and seed fertilities, of the (caudata)-CCDD SB5F2 were compared with those of the euplasmic Ae. cylindrica. The results indicated that the male sterility expressed by (caudata)-CCDD was due to genetic incompatibility between the Ae. cylindrica genome and Ae. caudata plasmon that did not affect any other characters of Ae. cylindrica. Also, we report that the genome integrity functions in keeping the univalent transmission rate high.

Observational Studies of the Clearing Phase in Proto-Planetary Disks Surrounding Intermediate Mass Stars

NASA Technical Reports Server (NTRS)

Grady, Carol A.

1999-01-01

A detailed study of circumstellar gas associated with young, intermediate-mass stars has demonstrated that, far from being unique or an infrequently occurring phenomenon, beta Pic-like infall activity is routinely observed in stars younger than 10-50 Myr when the observer's line of sight lies within 15 degrees of the disk mid-plane. Detailed studies of 2 Herbig Ae/Be stars, AB Aur and HD 163296 demonstrate that enhanced infall episodes last 20-60 hours, comparable to the duration of similar episodes in beta Pictoris. The infall activity is consistent with detection of the comae of swarms of star-grazing bodies of asteroidal to cometary composition. Episodic fluctuations in the infall activity are clearly present by approximately 6 Myr, and may indicate the presence of massive planets within the disk. This study has therefore, directly contributed to NASA's Origins of Planetary Systems theme by identifying under what conditions extra-solar planetesimals can be remotely sensed, indicating that such bodies appear to be routinely detectable among young stars in the 1-10 Myr range, and suggesting that temporal studies of spectroscopic variability may provide a means of identifying those systems harboring massive planets. This study has resulted in 2 refereed review papers, 13 other refereed papers, and 17 conference papers.

Searching for δ Scuti-type pulsation and characterising northern pre-main-sequence field stars

NASA Astrophysics Data System (ADS)

Díaz-Fraile, D.; Rodríguez, E.; Amado, P. J.

2014-08-01

Context. Pre-main-sequence (PMS) stars are objects evolving from the birthline to the zero-age main sequence (ZAMS). Given a mass range near the ZAMS, the temperatures and luminosities of PMS and main-sequence stars are very similar. Moreover, their evolutionary tracks intersect one another causing some ambiguity in the determination of their evolutionary status. In this context, the detection and study of pulsations in PMS stars is crucial for differentiating between both types of stars by obtaining information of their interiors via asteroseismic techniques. Aims: A photometric variability study of a sample of northern field stars, which previously classified as either PMS or Herbig Ae/Be objects, has been undertaken with the purpose of detecting δ Scuti-type pulsations. Determination of physical parameters for these stars has also been carried out to locate them on the Hertzsprung-Russell diagram and check the instability strip for this type of pulsators. Methods: Multichannel photomultiplier and CCD time series photometry in the uvby Strömgren and BVI Johnson bands were obtained during four consecutive years from 2007 to 2010. The light curves have been analysed, and a variability criterion has been established. Among the objects classified as variable stars, we have selected those which present periodicities above 4 d-1, which was established as the lowest limit for δ Scuti-type pulsations in this investigation. Finally, these variable stars have been placed in a colour-magnitude diagram using the physical parameters derived with the collected uvbyβ Strömgren-Crawford photometry. Results: Five PMS δ Scuti- and three probable β Cephei-type stars have been detected. Two additional PMS δ Scuti stars are also confirmed in this work. Moreover, three new δ Scuti- and two γ Doradus-type stars have been detected among the main-sequence objects used as comparison or check stars.

An Improved Recovery Algorithm for Decayed AES Key Schedule Images

NASA Astrophysics Data System (ADS)

Tsow, Alex

A practical algorithm that recovers AES key schedules from decayed memory images is presented. Halderman et al. [1] established this recovery capability, dubbed the cold-boot attack, as a serious vulnerability for several widespread software-based encryption packages. Our algorithm recovers AES-128 key schedules tens of millions of times faster than the original proof-of-concept release. In practice, it enables reliable recovery of key schedules at 70% decay, well over twice the decay capacity of previous methods. The algorithm is generalized to AES-256 and is empirically shown to recover 256-bit key schedules that have suffered 65% decay. When solutions are unique, the algorithm efficiently validates this property and outputs the solution for memory images decayed up to 60%.

Competence of Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus Mosquitoes as Zika Virus Vectors, China.

PubMed

Liu, Zhuanzhuan; Zhou, Tengfei; Lai, Zetian; Zhang, Zhenhong; Jia, Zhirong; Zhou, Guofa; Williams, Tricia; Xu, Jiabao; Gu, Jinbao; Zhou, Xiaohong; Lin, Lifeng; Yan, Guiyun; Chen, Xiao-Guang

2017-07-01

In China, the prevention and control of Zika virus disease has been a public health threat since the first imported case was reported in February 2016. To determine the vector competence of potential vector mosquito species, we experimentally infected Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus mosquitoes and determined infection rates, dissemination rates, and transmission rates. We found the highest vector competence for the imported Zika virus in Ae. aegypti mosquitoes, some susceptibility of Ae. albopictus mosquitoes, but no transmission ability for Cx. quinquefasciatus mosquitoes. Considering that, in China, Ae. albopictus mosquitoes are widely distributed but Ae. aegypti mosquito distribution is limited, Ae. albopictus mosquitoes are a potential primary vector for Zika virus and should be targeted in vector control strategies.

Competence of Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus Mosquitoes as Zika Virus Vectors, China

PubMed Central

Liu, Zhuanzhuan; Zhou, Tengfei; Lai, Zetian; Zhang, Zhenhong; Jia, Zhirong; Zhou, Guofa; Williams, Tricia; Xu, Jiabao; Gu, Jinbao; Zhou, Xiaohong; Lin, Lifeng; Yan, Guiyun

2017-01-01

In China, the prevention and control of Zika virus disease has been a public health threat since the first imported case was reported in February 2016. To determine the vector competence of potential vector mosquito species, we experimentally infected Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus mosquitoes and determined infection rates, dissemination rates, and transmission rates. We found the highest vector competence for the imported Zika virus in Ae. aegypti mosquitoes, some susceptibility of Ae. albopictus mosquitoes, but no transmission ability for Cx. quinquefasciatus mosquitoes. Considering that, in China, Ae. albopictus mosquitoes are widely distributed but Ae. aegypti mosquito distribution is limited, Ae. albopictus mosquitoes are a potential primary vector for Zika virus and should be targeted in vector control strategies. PMID:28430562

Performance analysis of AES-Blowfish hybrid algorithm for security of patient medical record data

NASA Astrophysics Data System (ADS)

Mahmud H, Amir; Angga W, Bayu; Tommy; Marwan E, Andi; Siregar, Rosyidah

2018-04-01

A file security is one method to protect data confidentiality, integrity and information security. Cryptography is one of techniques used to secure and guarantee data confidentiality by doing conversion to the plaintext (original message) to cipher text (hidden message) with two important processes, they are encrypt and decrypt. Some researchers proposed a hybrid method to improve data security. In this research we proposed hybrid method of AES-blowfish (BF) to secure the patient’s medical report data into the form PDF file that sources from database. Generation method of private and public key uses two ways of approach, those are RSA method f RSA and ECC. We will analyze impact of these two ways of approach for hybrid method at AES-blowfish based on time and Throughput. Based on testing results, BF method is faster than AES and AES-BF hybrid, however AES-BF hybrid is better for throughput compared with AES and BF is higher.

Phylogenetic and Temporal Dynamics of Human Immunodeficiency Virus Type 1 CRF01_AE in China

PubMed Central

Su, Xueli; Lu, Hongyan; Pang, Xinghuo; Yan, Hong; Feng, Xia; He, Xiong; Zeng, Yi

2013-01-01

To explore the epidemic history of HIV-1 CRF01_AE in China, 408 fragments of gag gene sequences of CRF01_AE sampled in 2002–2010 were determined from different geographical regions and risk populations in China. Phylogenetic analysis indicates that the CRF01_AE sequences can be grouped into four clusters, suggesting that at least four genetically independent CRF01_AE descendants are circulating in China, of which two were closely related to the isolates from Thailand and Vietnam. Cluster 1 has the most extensive distribution in China. In North China, cluster 1 and cluster 4 were mainly transmitted through homosexuality.The real substance of the recent HIV-1 epidemic in men who have sex with men(MSM) of North China is a rapid spread of CRF01_AE, or rather two distinctive natives CRF01_AE.The time of the most recent common ancestor (tMRCA) of four CRF01_AE clusters ranged from the years 1990.9 to 2003.8 in different regions of China. This is the first phylogenetic and temporal dynamics study of HIV-1 CRF01_AE in China. PMID:23365653

Suppression of colon cancer metastasis by Aes through inhibition of Notch signaling.

PubMed

Sonoshita, Masahiro; Aoki, Masahiro; Fuwa, Haruhiko; Aoki, Koji; Hosogi, Hisahiro; Sakai, Yoshiharu; Hashida, Hiroki; Takabayashi, Arimichi; Sasaki, Makoto; Robine, Sylvie; Itoh, Kazuyuki; Yoshioka, Kiyoko; Kakizaki, Fumihiko; Kitamura, Takanori; Oshima, Masanobu; Taketo, Makoto Mark

2011-01-18

Metastasis is responsible for most cancer deaths. Here, we show that Aes (or Grg5) gene functions as an endogenous metastasis suppressor. Expression of Aes was decreased in liver metastases compared with primary colon tumors in both mice and humans. Aes inhibited Notch signaling by converting active Rbpj transcription complexes into repression complexes on insoluble nuclear matrix. In tumor cells, Notch signaling was triggered by ligands on adjoining blood vessels, and stimulated transendothelial migration. Genetic depletion of Aes in Apc(Δ716) intestinal polyposis mice caused marked tumor invasion and intravasation that were suppressed by Notch signaling inhibition. These results suggest that inhibition of Notch signaling can be a promising strategy for prevention and treatment of colon cancer metastasis. Copyright © 2011 Elsevier Inc. All rights reserved.

Far-infrared observations of a star-forming region in the Corona Australis dark cloud

NASA Technical Reports Server (NTRS)

Cruz-Gonzalez, I.; Mcbreen, B.; Fazio, G. G.

1984-01-01

A high-resolution far-IR (40-250-micron) survey of a 0.9-sq-deg section of the core region of the Corona Australis dark cloud (containing very young stellar objects such as T Tauri stars, Herbig Ae and Be stars, Herbig-Haro objects, and compact H II regions) is presented. Two extended far-IR sources were found, one associated with the Herbig emission-line star R CrA and the other with the irregular emission-line variable star TY CrA. The two sources have substantially more far-IR radiation than could be expected from a blackbody extrapolation of their near-IR fluxes. The total luminosities of these sources are 145 and 58 solar luminosity, respectively, implying that the embedded objects are of intermediate or low mass. The infrared observations of the sources associated with R CrA and TY CrA are consistent with models of the evolution of protostellar envelopes of intermediate mass. However, the TY CrA source appears to have passed the evolutionary stage of expelling most of the hot dust near the central source, yielding an age of about 1 Myr.

Observational Studies of Protoplanetary Disks at Mid-Infrared Wavelengths

NASA Astrophysics Data System (ADS)

Li, Dan; Telesco, Charles; Wright, Christopher; Packham, Christopher; Marinas, Naibi

2013-07-01

We have used mid-infrared cameras on 8-to-10 m class telescopes to study the properties of young circumstellar disks. During the initial phases of this program we examined a large sample of mid-IR images of standard stars delivered by T-ReCS at Gemini South to evaluate its on-sky performance as characterized by, for example the angular resolution, the PSF shape, and the PSF temporal stability, properties that are most relevant to our high-angular resolution study of disks. With this information we developed an Interactive Data Language (IDL) package of routines optimized for reducing the data and correcting for image defects commonly seen in ground-based mid-IR data. We obtained, reduced, and analyzed mid-IR images and spectra of several Herbig Ae/Be disks (including HD 259431, MWC 1080, VV Ser) and the debris disk (β Pic), and derived their physical properties by means of radiative transfer modeling or spectroscopic decomposition and analyses. These results are highlighted here. During this study, we also helped commission CanariCam, a new mid-IR facility instrument built by the University of Florida for the 10.4 m Gran Telescopio Canarias (GTC) on La Palma, Canary Islands, Spain. CanariCam is an imager with spectroscopic, polarimetric, and coronagraphic capabilities, with the dual-beam polarimetry being a unique mode introduced with CanariCam for the first time to a 10 m telescope at mid-IR wavelengths. It is well known that measurements of polarization, originating from aligned dust grains in the disks and their environments, have the potential to shed light on the morphologies of the magnetic fields in these regions, information that is critical to understanding how stars and planets form. We have obtained polarimetric data of several Herbig Ae/Be disks and YSOs, and the data reduction and analyses are in process. We present preliminary results here. This poster is based upon work supported by the NSF under grant AST-0903672 and AST-0908624 awarded to C.M.T.

Amino-terminal enhancer of split gene AES encodes a tumor and metastasis suppressor of prostate cancer.

PubMed

Okada, Yoshiyuki; Sonoshita, Masahiro; Kakizaki, Fumihiko; Aoyama, Naoki; Itatani, Yoshiro; Uegaki, Masayuki; Sakamoto, Hiromasa; Kobayashi, Takashi; Inoue, Takahiro; Kamba, Tomomi; Suzuki, Akira; Ogawa, Osamu; Taketo, M Mark

2017-04-01

A major cause of cancer death is its metastasis to the vital organs. Few effective therapies are available for metastatic castration-resistant prostate cancer (PCa), and progressive metastatic lesions such as lymph nodes and bones cause mortality. We recently identified AES as a metastasis suppressor for colon cancer. Here, we have studied the roles of AES in PCa progression. We analyzed the relationship between AES expression and PCa stages of progression by immunohistochemistry of human needle biopsy samples. We then performed overexpression and knockdown of AES in human PCa cell lines LNCaP, DU145 and PC3, and determined the effects on proliferation, invasion and metastasis in culture and in a xenograft model. We also compared the PCa phenotypes of Aes/Pten compound knockout mice with those of Pten simple knockout mice. Expression levels of AES were inversely correlated with clinical stages of human PCa. Exogenous expression of AES suppressed the growth of LNCaP cells, whereas the AES knockdown promoted it. We also found that AES suppressed transcriptional activities of androgen receptor and Notch signaling. Notably, AES overexpression in AR-defective DU145 and PC3 cells reduced invasion and metastasis to lymph nodes and bones without affecting proliferation in culture. Consistently, prostate epithelium-specific inactivation of Aes in Pten flox/flox mice increased expression of Snail and MMP9, and accelerated growth, invasion and lymph node metastasis of the mouse prostate tumor. These results suggest that AES plays an important role in controlling tumor growth and metastasis of PCa by regulating both AR and Notch signaling pathways. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Using Kepler K2 to Measure the Binary Fraction of PN Central Stars

NASA Astrophysics Data System (ADS)

Jacoby, George H.; Hillwig, Todd; De Marco, Orsola; Hurowitz, Jonathan; Jones, David; Kronberger, Matthias; Harmer, Dianne

2018-01-01

During the initial Kepler mission, 5 Planetary Nebula (PN) central stars were observed. The light curves for 4 of these central stars indicated a history of close binary interactions. That large fraction was suggestive that the actual fraction of PN harboring close binaries is much larger than the known lower limit of 20%, but that sample is far too small to be compelling. We have since acquired Kepler K2 data for Campaigns 0, 2, 7, and 11, hosting PN samples of 3, 4, 8, and 185 targets, respectively. We will provide an update on the number of binary candidates found in each field, and in particular, the Galactic Bulge field of Campaign 11. We also will discuss the challenges of working with Kepler observations in the crowded Campaign 11 field and the impact of those challenges on our ability to estimate the fraction of PN central stars that are binaries. This study was supported in part by NASA grants NNX17AE64G and NNX17AF80G.

Prognostic assessment in COPD without lung function: the B-AE-D indices.

PubMed

Boeck, Lucas; Soriano, Joan B; Brusse-Keizer, Marjolein; Blasi, Francesco; Kostikas, Konstantinos; Boersma, Wim; Milenkovic, Branislava; Louis, Renaud; Lacoma, Alicia; Djamin, Remco; Aerts, Joachim; Torres, Antoni; Rohde, Gernot; Welte, Tobias; Martinez-Camblor, Pablo; Rakic, Janko; Scherr, Andreas; Koller, Michael; van der Palen, Job; Marin, Jose M; Alfageme, Inmaculada; Almagro, Pere; Casanova, Ciro; Esteban, Cristobal; Soler-Cataluña, Juan J; de-Torres, Juan P; Miravitlles, Marc; Celli, Bartolome R; Tamm, Michael; Stolz, Daiana

2016-06-01

Several composite markers have been proposed for risk assessment in chronic obstructive pulmonary disease (COPD). However, choice of parameters and score complexity restrict clinical applicability. Our aim was to provide and validate a simplified COPD risk index independent of lung function.The PROMISE study (n=530) was used to develop a novel prognostic index. Index performance was assessed regarding 2-year COPD-related mortality and all-cause mortality. External validity was tested in stable and exacerbated COPD patients in the ProCOLD, COCOMICS and COMIC cohorts (total n=2988).Using a mixed clinical and statistical approach, body mass index (B), severe acute exacerbations of COPD frequency (AE), modified Medical Research Council dyspnoea severity (D) and copeptin (C) were identified as the most suitable simplified marker combination. 0, 1 or 2 points were assigned to each parameter and totalled to B-AE-D or B-AE-D-C. It was observed that B-AE-D and B-AE-D-C were at least as good as BODE (body mass index, airflow obstruction, dyspnoea, exercise capacity), ADO (age, dyspnoea, airflow obstruction) and DOSE (dyspnoea, obstruction, smoking, exacerbation) indices for predicting 2-year all-cause mortality (c-statistic: 0.74, 0.77, 0.69, 0.72 and 0.63, respectively; Hosmer-Lemeshow test all p>0.05). Both indices were COPD specific (c-statistic for predicting COPD-related 2-year mortality: 0.87 and 0.89, respectively). External validation of B-AE-D was performed in COCOMICS and COMIC (c-statistic for 1-year all-cause mortality: 0.68 and 0.74; c-statistic for 2-year all-cause mortality: 0.65 and 0.67; Hosmer-Lemeshow test all p>0.05).The B-AE-D index, plus copeptin if available, allows a simple and accurate assessment of COPD-related risk. Copyright ©ERS 2016.

Prognostic assessment in COPD without lung function: the B-AE-D indices

PubMed Central

Boeck, Lucas; Blasi, Francesco; Kostikas, Konstantinos; Boersma, Wim; Milenkovic, Branislava; Louis, Renaud; Lacoma, Alicia; Djamin, Remco; Aerts, Joachim; Torres, Antoni; Rohde, Gernot; Welte, Tobias; Martinez-Camblor, Pablo; Rakic, Janko; Scherr, Andreas; Koller, Michael; van der Palen, Job; Marin, Jose M.; Alfageme, Inmaculada; Almagro, Pere; Casanova, Ciro; Esteban, Cristobal; Soler-Cataluña, Juan J.; de-Torres, Juan P.; Miravitlles, Marc; Celli, Bartolome R.; Tamm, Michael

2016-01-01

Several composite markers have been proposed for risk assessment in chronic obstructive pulmonary disease (COPD). However, choice of parameters and score complexity restrict clinical applicability. Our aim was to provide and validate a simplified COPD risk index independent of lung function. The PROMISE study (n=530) was used to develop a novel prognostic index. Index performance was assessed regarding 2-year COPD-related mortality and all-cause mortality. External validity was tested in stable and exacerbated COPD patients in the ProCOLD, COCOMICS and COMIC cohorts (total n=2988). Using a mixed clinical and statistical approach, body mass index (B), severe acute exacerbations of COPD frequency (AE), modified Medical Research Council dyspnoea severity (D) and copeptin (C) were identified as the most suitable simplified marker combination. 0, 1 or 2 points were assigned to each parameter and totalled to B-AE-D or B-AE-D-C. It was observed that B-AE-D and B-AE-D-C were at least as good as BODE (body mass index, airflow obstruction, dyspnoea, exercise capacity), ADO (age, dyspnoea, airflow obstruction) and DOSE (dyspnoea, obstruction, smoking, exacerbation) indices for predicting 2-year all-cause mortality (c-statistic: 0.74, 0.77, 0.69, 0.72 and 0.63, respectively; Hosmer–Lemeshow test all p>0.05). Both indices were COPD specific (c-statistic for predicting COPD-related 2-year mortality: 0.87 and 0.89, respectively). External validation of B-AE-D was performed in COCOMICS and COMIC (c-statistic for 1-year all-cause mortality: 0.68 and 0.74; c-statistic for 2-year all-cause mortality: 0.65 and 0.67; Hosmer–Lemeshow test all p>0.05). The B-AE-D index, plus copeptin if available, allows a simple and accurate assessment of COPD-related risk. PMID:27103389

Spectral Characteristics of Continuous Acoustic Emission (AE) Data from Laboratory Rock Deformation Experiments

NASA Astrophysics Data System (ADS)

Flynn, J. William; Goodfellow, Sebastian; Reyes-Montes, Juan; Nasseri, Farzine; Young, R. Paul

2016-04-01

Continuous acoustic emission (AE) data recorded during rock deformation tests facilitates the monitoring of fracture initiation and propagation due to applied stress changes. Changes in the frequency and energy content of AE waveforms have been previously observed and were associated with microcrack coalescence and the induction or mobilisation of large fractures which are naturally associated with larger amplitude AE events and lower-frequency components. The shift from high to low dominant frequency components during the late stages of the deformation experiment, as the rate of AE events increases and the sample approaches failure, indicates a transition from the micro-cracking to macro-cracking regime, where large cracks generated result in material failure. The objective of this study is to extract information on the fracturing process from the acoustic records around sample failure, where the fast occurrence of AE events does not allow for identification of individual AE events and phase arrivals. Standard AE event processing techniques are not suitable for extracting this information at these stages. Instead the observed changes in the frequency content of the continuous record can be used to characterise and investigate the fracture process at the stage of microcrack coalescence and sample failure. To analyse and characterise these changes, a detailed non-linear and non-stationary time-frequency analysis of the continuous waveform data is required. Empirical Mode Decomposition (EMD) and Hilbert Spectral Analysis (HSA) are two of the techniques used in this paper to analyse the acoustic records which provide a high-resolution temporal frequency distribution of the data. In this paper we present the results from our analysis of continuous AE data recorded during a laboratory triaxial deformation experiment using the combined EMD and HSA method.

Anisotropic electrical and thermal conductivity in Bi2AE2Co2O8+δ [AE = Ca, Sr1-xBax (x = 0.0, 0.25, 0.5, 0.75, 1.0)] single crystals

NASA Astrophysics Data System (ADS)

Dong, Song-Tao; Zhang, Bin-Bin; Xiong, Ye; Lv, Yang-Yang; Yao, Shu-Hua; Chen, Y. B.; Zhou, Jian; Zhang, Shan-Tao; Chen, Yan-Feng

2015-09-01

Bi2AE2Co2O8+δ (AE represents alkaline earth), constructed by stacking of rock-salt Bi2AE2O4 and triangle CoO2 layers alternatively along c-axis, is one of promising thermoelectric oxides. The most impressive feature of Bi2AE2Co2O8+δ, as reported previously, is their electrical conductivity mainly lying along CoO2 plane, adjusting Bi2AE2O4 layer simultaneously manipulates both thermal conductivity and electrical conductivity. It in turn optimizes thermoelectric performance of these materials. In this work, we characterize the anisotropic thermal and electrical conductivity along both ab-plane and c-direction of Bi2AE2Co2O8+δ (AE = Ca, Sr, Ba, Sr1-xBax) single crystals. The results substantiate that isovalence replacement in Bi2AE2Co2O8+δ remarkably modifies their electrical property along ab-plane; while their thermal conductivity along ab-plane only has a slightly difference. At the same time, both the electrical conductivity and thermal conductivity along c-axis of these materials also have dramatic changes. Certainly, the electrical resistance along c-axis is too high to be used as thermoelectric applications. These results suggest that adjusting nano-block Bi2AE2O4 layer in Bi2AE2Co2O8+δ cannot modify the thermal conductivity along high electrical conductivity plane (ab-plane here). The evolution of electrical property is discussed by Anderson localization and electron-electron interaction U. And the modification of thermal conductivity along c-axis is attributed to the microstructure difference. This work sheds more light on the manipulation of the thermal and electrical conductivity in the layered thermoelectric materials.

Some performance tests of a microarea AES. [Auger Electron Spectroscopy

NASA Technical Reports Server (NTRS)

Todd, G.; Poppa, H.

1978-01-01

An Auger electron spectroscopy (AES) system which has a submicron analysis capability is described. The system provides secondary electron imaging, as well as micro- and macro-area AES. The resolution of the secondary electron image of an oxidized Al contact pad on a charge-coupled device chip indicates a primary beam size of about 1000 A. For Auger mapping, a useful resolution of about 4000 A is reported

Complete chloroplast genomes of Aegilops tauschii Coss. and Ae. cylindrica Host sheds light on plasmon D evolution.

PubMed

Gogniashvili, Mari; Jinjikhadze, Tamar; Maisaia, Inesa; Akhalkatsi, Maia; Kotorashvili, Adam; Kotaria, Nato; Beridze, Tengiz; Dudnikov, Alexander Ju

2016-11-01

Hexaploid wheat (Triticum aestivum L., genomes AABBDD) originated in South Caucasus by allopolyploidization of the cultivated Emmer wheat T. dicoccum (genomes AABB) with the Caucasian Ae. tauschii ssp strangulata (genomes DD). Genetic variation of Ae. tauschii is an important natural resource, that is why it is of particular importance to investigate how this variation was formed during Ae. tauschii evolutionary history and how it is presented through the species area. The D genome is also found in tetraploid Ae. cylindrica Host (2n = 28, CCDD). The plasmon diversity that exists in Triticum and Aegilops species is of great significance for understanding the evolution of these genera. In the present investigation the complete nucleotide sequence of plasmon D (chloroplast DNA) of nine accessions of Ae. tauschii and two accessions of Ae. cylindrica are presented. Twenty-eight SNPs are characteristic for both TauL1 and TauL2 accessions of Ae. tauschii using TauL3 as a reference. Four SNPs are additionally observed for TauL2 lineage. The longest (27 bp) indel is located in the intergenic spacer Rps15-ndhF of SSC. This indel can be used for simple determination of TauL3 lineage among Ae. tauschii accessions. In the case of Ae. cylindrica additionally 7 SNPs were observed. The phylogeny tree shows that chloroplast DNA of TauL1 and TauL2 diverged from the TauL3 lineage. TauL1 lineage is relatively older then TauL2. The position of Ae. cylindrica accessions on Ae. tauschii phylogeny tree constructed on chloroplast DNA variation data is intermediate between TauL1 and TauL2. The complete nucleotide sequence of chloroplast DNA of Ae. tauschii and Ae. cylindrica allows to refine the origin and evolution of D plasmon of genus Aegilops.

Action stations to relieve A&E.

PubMed

Moore, Alison

Trusts have taken steps to avoid a repeat of list winter's pressures on A&E. Work is also under way on an NHS England blueprint to transform urgent and emergency care. Nurses will play a part in reshaping the system, but all the moment many are stressed by working under excessive pressure all year round.

Two types of geomagnetic storms and relationship between Dst and AE indexes

NASA Astrophysics Data System (ADS)

Shadrina, Lyudmila P.

2017-10-01

The study of the relationship between Dst and AE indices of the geomagnetic field and its manifestation in geomagnetic storms in the XXIII solar cycle was carried out. It is shown that geomagnetic storms are divided into two groups according to the ratio of the amplitude of Ds index decrease to the sum of the AE index during the main phase of the storm. For the first group it is characteristic that for small depressions of the Dst index, significant amounts of the AE index are observed. Most often these are storms with a gradual beginning and a long main phase associated with recurrent solar wind streams. Storms of the second group differ in large amplitudes of Dst index decrease, shorter duration of main phase and small amounts of AE-index. Usually these are sporadic geomagnetic storms with a sudden commencement caused by interplanetary disturbances of the CME type. The storms of these two types differ also in their geoeffects, including the effect on human health.

Preflight and Inflight Calibration of TES and AES

NASA Technical Reports Server (NTRS)

Rider, David M.

1997-01-01

The Thermal Emission Spectrometer (TES), an EOS CHEM platform instrument, and its companion instrument, the Airborne Emission Spectrometer (AES), are both Fourier transform spectrometers designed for remote sensing of the troposphere.

Herschel Studies of the Evolution and Environs of Young Stars in the DIGIT, WISH, and FOOSH Programs

NASA Astrophysics Data System (ADS)

Green, Joel D.; DIGIT OT Key Project Team; WISH GT Key Project Team; FOOSH OT1 Team

2012-01-01

The Herschel Space Observatory has enabled us to probe the physical conditions of outer disks, envelopes, and outflows of young stellar objects, including embedded objects, Herbig Ae/Be disks, and T Tauri disks. We will report on results from three projects, DIGIT, WISH, and FOOSH. The DIGIT (Dust, Ice, and Gas in Time) program (PI: Neal Evans) utilizes the full spectral range of the PACS instrument to explore simultaneously the solid and gas-phase chemistry around sources in all of these stages. WISH (Water in Star Forming Regions with Herschel, PI Ewine van Dishoeck) focuses on observations of key lines with HIFI and line scans of selected spectral regions with PACS. FOOSH (FU Orionis Objects Surveyed with Herschel, PI Joel Green) studies FU Orionis objects with full range PACS and SPIRE scans. DIGIT includes examples of low luminosity protostars, while FOOSH studies the high luminosity objects during outburst states. Rotational ladders of highly excited CO and OH emission are detected in both disks and protostars. The highly excited lines are more commonly seen in the embedded phases, where there appear to be two temperature components. Intriguingly, water is frequently detected in spectra of embedded sources, but not in the disk spectra. In addition to gas features, we explore the extent of the newly detected 69 um forsterite dust feature in both T Tauri and Herbig Ae/Be stars. When analyzed along with the Spitzer-detected dust features, these provide constraints on a population of colder crystalline material. We will present some models of individual sources, as well as some broad statistics of the emission from these stages of star and planet formation.

AE Geomagnetic Index Predictability for High Speed Solar Wind Streams: A Wavelet Decomposition Technique

NASA Technical Reports Server (NTRS)

Guarnieri, Fernando L.; Tsurutani, Bruce T.; Hajra, Rajkumar; Echer, Ezequiel; Gonzalez, Walter D.; Mannucci, Anthony J.

2014-01-01

High speed solar wind streams cause geomagnetic activity at Earth. In this study we have applied a wavelet interactive filtering and reconstruction technique on the solar wind magnetic field components and AE index series to allowed us to investigate the relationship between the two. The IMF Bz component was found as the most significant solar wind parameter responsible by the control of the AE activity. Assuming magnetic reconnection associated to southward directed Bz is the main mechanism transferring energy into the magnetosphere, we adjust parameters to forecast the AE index. The adjusted routine is able to forecast AE, based only on the Bz measured at the L1 Lagrangian point. This gives a prediction approximately 30-70 minutes in advance of the actual geomagnetic activity. The correlation coefficient between the observed AE data and the forecasted series reached values higher than 0.90. In some cases the forecast reproduced particularities observed in the signal very well.The high correlation values observed and the high efficacy of the forecasting can be taken as a confirmation that reconnection is the main physical mechanism responsible for the energy transfer during HILDCAAs. The study also shows that the IMF Bz component low frequencies are most important for AE prediction.

Secretome of transmissible Pseudomonas aeruginosa AES-1R grown in a cystic fibrosis lung-like environment.

PubMed

Scott, Nichollas E; Hare, Nathan J; White, Melanie Y; Manos, Jim; Cordwell, Stuart J

2013-12-06

Pseudomonas aeruginosa is the predominant cause of mortality in patients with cystic fibrosis (CF). We examined the secretome of an acute, transmissible CF P. aeruginosa (Australian epidemic strain 1-R; AES-1R) compared with laboratory-adapted PAO1. Culture supernatant proteins from rich (LB) and minimal (M9) media were compared using 2-DE and 2DLC-MS/MS, which revealed elevated abundance of PasP protease and absence of AprA protease in AES-1R. CF lung-like artificial sputum medium (ASMDM) contains serum and mucin that generally preclude proteomics of secreted proteins. ASMDM culture supernatants were subjected to 2DLC-MS/MS, which allowed the identification of 57 P. aeruginosa proteins, and qualitative spectral counting was used to estimate relative abundance. AES-1R-specific AES_7139 and PasP were more abundant in AES-1R ASMDM culture supernatants, while AprA could only be identified in PAO1. Relative quantitation was performed using selected reaction monitoring. Significantly elevated levels of PasP, LasB, chitin-binding protein (CbpD), and PA4495 were identified in AES-1R ASMDM supernatants. Quantitative PCR showed elevated pasP in AES-1R during early (18 h) ASMDM growth, while no evidence of aprA expression could be observed. Genomic screening of CF isolates revealed aes_7139 was present in all AES-1 and one pair of sequential nonepidemic isolates. Secreted proteins may be crucial in aiding CF-associated P. aeruginosa to establish infection and for adaptation to the CF lung.

Matt Rogers on AES Energy Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, Matt

2010-08-02

The Department of Energy and AES Energy Storage recently agreed to a $17.1M conditional loan guarantee commitment. This project will develop the first battery-based energy storage system to provide a more stable and efficient electrical grid for New York State's high-voltage transmission network. Matt Rogers is the Senior Advisor to the Secretary for Recovery Act Implementation.

Matt Rogers on AES Energy Storage

ScienceCinema

Rogers, Matt

2017-12-29

The Department of Energy and AES Energy Storage recently agreed to a $17.1M conditional loan guarantee commitment. This project will develop the first battery-based energy storage system to provide a more stable and efficient electrical grid for New York State's high-voltage transmission network. Matt Rogers is the Senior Advisor to the Secretary for Recovery Act Implementation.

The inner zone electron model AE-5

NASA Technical Reports Server (NTRS)

Teague, M. J.; Vette, J. I.

1972-01-01

A description is given of the work performed in the development of the inner radiation zone electron model, AE-5. A complete description of the omnidirectional flux model is given for energy thresholds E sub T in the range 4.0 E sub T/(MeV) 0.04 and for L values in the range 2.8 L 1.2 for an epoch of October 1967. Confidence codes for certain regions of B-L space and certain energies are given based on data coverage and the assumptions made in the analysis. The electron model programs that can be supplied to a user are referred to. One of these, a program for accessing the model flux at arbitrary points in B-L space and arbitrary energies, includes the latest outer zone electron model and proton model. The model AE-5, is based on data from five satellites, OGO 1, OGO 3, 1963-38C, OV3-3, and Explorer 26, spanning the period December 1964 to December 1967.

19 CFR 192.13 - Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 2 2011-04-01 2011-04-01 false Revocation of participants' AES post-departure... Filing of Export Information Through the Automated Export System (AES) § 192.13 Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures. (a) Reasons for revocation...

19 CFR 192.13 - Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 2 2012-04-01 2012-04-01 false Revocation of participants' AES post-departure... Filing of Export Information Through the Automated Export System (AES) § 192.13 Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures. (a) Reasons for revocation...

19 CFR 192.13 - Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 2 2014-04-01 2014-04-01 false Revocation of participants' AES post-departure... Filing of Export Information Through the Automated Export System (AES) § 192.13 Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures. (a) Reasons for revocation...

19 CFR 192.13 - Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 2 2013-04-01 2013-04-01 false Revocation of participants' AES post-departure... Filing of Export Information Through the Automated Export System (AES) § 192.13 Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures. (a) Reasons for revocation...

[Quantitative surface analysis of Pt-Co, Cu-Au and Cu-Ag alloy films by XPS and AES].

PubMed

Li, Lian-Zhong; Zhuo, Shang-Jun; Shen, Ru-Xiang; Qian, Rong; Gao, Jie

2013-11-01

In order to improve the quantitative analysis accuracy of AES, We associated XPS with AES and studied the method to reduce the error of AES quantitative analysis, selected Pt-Co, Cu-Au and Cu-Ag binary alloy thin-films as the samples, used XPS to correct AES quantitative analysis results by changing the auger sensitivity factors to make their quantitative analysis results more similar. Then we verified the accuracy of the quantitative analysis of AES when using the revised sensitivity factors by other samples with different composition ratio, and the results showed that the corrected relative sensitivity factors can reduce the error in quantitative analysis of AES to less than 10%. Peak defining is difficult in the form of the integral spectrum of AES analysis since choosing the starting point and ending point when determining the characteristic auger peak intensity area with great uncertainty, and to make analysis easier, we also processed data in the form of the differential spectrum, made quantitative analysis on the basis of peak to peak height instead of peak area, corrected the relative sensitivity factors, and verified the accuracy of quantitative analysis by the other samples with different composition ratio. The result showed that the analytical error in quantitative analysis of AES reduced to less than 9%. It showed that the accuracy of AES quantitative analysis can be highly improved by the way of associating XPS with AES to correct the auger sensitivity factors since the matrix effects are taken into account. Good consistency was presented, proving the feasibility of this method.

[Construction and pathogenic identification of aes-31 gene mutant of avian pathogenic Escherichia coli strain E058].

PubMed

Huan, Haixia; Zhang, Ke; Chen, Xiang; Gao, Song; Liu, Xiufan

2010-12-01

To find the primary function of aes-31 fragment through construction of defined mutation of Avian Pathogenic Escherichia coli strain E058 and animal experiments. The fragment of aes-31 was generated by PCR and cloned into pGEM-T-easy vector. A resultant suicide vector containing the aes-31 fragment named pMEG375-aes-31 was constructed and transformed to a receptor strain SM10. Then recombinant strain SM10 was hybridized with E058 strain in solid state. Mutant derivatives of strain E058 were generated by homologous recombination and were named E058 (delta aes-31). The 50% lethal dose (LD50) of E058 and E058 (delta aes-31) in commercial day-old chickens experimentally inoculated via intratrachea were 10(4.3) CFU and 10(3.5) CFU, respectively. The same way was used to inoculate with 10(8) CFU to obtain the pathogenic ability of E058 and E058 (delta aes-31) in 35-days-old SPF chickens. In the chicken challenge model,the mutant was tested to determine the individual function for virulence and persistence in 2-week-old SPF chicks. The pathogenicity test for E058 strain and E058 (delta aes-31) strain showed that the mutant had a higher mortality (75%) to 35-day-old specific pathogen-free (SPF) chicks than that of E058 (62.5%). In the chicken challenge model,there was no obviously CFUs difference in blood and lung in chicks of E058 group and E058 (delta aes-31) group 6 hours after inoculation. After 24 hours there was obvious CFUs difference in heart, liver, spleen, lung and blood in chicks of E058 group and E058 (delta aes-31) group. After 48 hours, there was also obvious CFUs difference in heart, liver and spleen in chicks of E058 group and E058 (delta aes-31) group E058 (delta aes-31) had a trend of increasing virulence in chicks. Aes-31 might be associated with negative regulatory gene for E058 virulence and its actual function needed further study.

Mumic acids A-E: new diterpenoids from mumiyo.

PubMed

Kiren, Yuko; Nugroho, Alfarius Eko; Hirasawa, Yusuke; Shirota, Osamu; Bekenova, Myrzaim; Narbekovich, Narbekov Omorbay; Shapilova, Marina; Maeno, Hiromichi; Morita, Hiroshi

2014-01-01

Five new diterpenoids belonging to labdane and isopimarane skeletons, mumic acids A-E (1-5), have been isolated from mumiyo. Their structures and absolute configurations were elucidated on the basis of spectroscopic data and chemical derivatization.

Atmosphere Explorer (AE) spacecraft system description

NASA Technical Reports Server (NTRS)

1972-01-01

The principal design and performance characteristics of the AE spacecraft system designed to support the Atmosphere Explorer C, D, and E missions are summarized. It has been prepared for the information of experimenters and other participants in the Atmosphere Explorer program as a general guide for design and operational planning. The description represents the spacecraft system as defined at the conclusion of the interface definition study.

Continuous AE crack monitoring of a dissimilar metal weldment at Limerick Unit 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hutton, P.H.; Friesel, M.A.; Dawson, J.F.

1993-12-01

Acoustic emission (AE) technology for continuous surveillance of a reactor component(s) to detect crack initiation and/or crack growth has been developed at Pacific Northwest Laboratory (PNL). The technology was validated off-reactor in several major tests, but it had not been validated by monitoring crack growth on an operating reactor system. A flaw indication was identified during normal inservice inspection of piping at Philadelphia Electric Company (PECO) Limerick Unit 1 reactor during the 1989 refueling outage. Evaluation of the flaw indication showed that it could remain in place during the subsequent fuel cycle without compromising safety. The existence of this flawmore » indication offered a long sought opportunity to validate AE surveillance to detect and evaluate crack growth during reactor operation. AE instrumentation was installed by PNL and PECO to monitor the flaw indication during two complete fuel cycles. This report discusses the results obtained from the AE monitoring over the period May 1989 to March 1992 (two fuel cycles).« less

Australian epidemic strain pseudomonas (AES-1) declines further in a cohort segregated cystic fibrosis clinic.

PubMed

Griffiths, Amanda L; Wurzel, Danielle F; Robinson, Phil J; Carzino, Rosemary; Massie, John

2012-01-01

To evaluate changes in prevalence of an epidemic strain of Pseudomonas aeruginosa (AES-1, Australian epidemic strain, type 1) in a paediatric cystic fibrosis (CF) centre practising cohort segregation, to describe the patients' clinical characteristics at acquisition and observe mortality rates. Cohort segregation was introduced in our paediatric CF clinic January 2000. The prevalence of AES-1 was analysed in 1999, 2002 and 2007. Age at acquisition, lung function, presence of bronchiectasis, hospitalisations, prior P. aeruginosa infection and mortality rates were collected. AES-1 infection was determined by pulse-field-gel-electrophoresis (PFGE) on airway specimen cultures taken three monthly. The prevalence of AES-1 declined from 21% in 1999 to 14% in 2002 (risk difference 7% (95% CI 1,13) p=0.0256) and to 6% in 2007 (risk difference 8% (95% CI 3,13) p=0.0018). New acquisitions after the introduction of cohort segregation were uncommon (10 by 2002 and another 7 by 2007) with a declining incidence of 3.3 cases/year (1999 to 2002) compared to 1.4 cases/year (2002 to 2007). Twenty-two of 32 (69%) deaths between 1999 and 2007 occurred in patients infected with AES-1. Cohort segregation has been associated with reductions in the prevalence of AES-1 in our CF clinic. Mortality was higher in patients infected with AES-1 than other organisms. Copyright © 2011 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

FUV Spectroscopy Of Outflows And Disks Around The Intermediate Mass Pre-main-sequence Stars HD135344B And HD104237

NASA Astrophysics Data System (ADS)

Brown, Alexander; Herczeg, G.; Brown, J. M.; Walter, F. M.; Ayres, T. R.; DAOof TAU Team

2011-01-01

The intermediate-mass, pre-main-sequence (Herbig Ae/Fe) stars HD135344B (F4) and HD104237 (A8 IV-V) are both still surrounded by almost face-on circumstellar disks. The disk around HD135344B is a ``transitional'' disk with a 25 AU radius cleared inner hole but still with some gas and dust very close to the star. We have obtained FUV spectra of these stars using the HST COS and STIS spectrographs that show that both stars have dramatic high-velocity (terminal velocity = 300-400 km/s) outflows and rich fluorescently-excited molecular hydrogen emission, originating primarily from warm gas in their disks. We present these FUV spectra and outline the outflow and disk properties implied by the observed emission and absorption line profiles. The profiles and widths of the molecular hydrogen lines provide strong constraints on the location of the emitting regions. This work is supported by HST grants for GO projects 11828 and 11616, and Chandra grant GO9-0015X to the University of Colorado.

Global temperature constraints on Aedes aegypti and Ae. albopictus persistence and competence for dengue virus transmission

PubMed Central

2014-01-01

Background Dengue is a disease that has undergone significant expansion over the past hundred years. Understanding what factors limit the distribution of transmission can be used to predict current and future limits to further dengue expansion. While not the only factor, temperature plays an important role in defining these limits. Previous attempts to analyse the effect of temperature on the geographic distribution of dengue have not considered its dynamic intra-annual and diurnal change and its cumulative effects on mosquito and virus populations. Methods Here we expand an existing modelling framework with new temperature-based relationships to model an index proportional to the basic reproductive number of the dengue virus. This model framework is combined with high spatial and temporal resolution global temperature data to model the effects of temperature on Aedes aegypti and Ae. albopictus persistence and competence for dengue virus transmission. Results Our model predicted areas where temperature is not expected to permit transmission and/or Aedes persistence throughout the year. By reanalysing existing experimental data our analysis indicates that Ae. albopictus, often considered a minor vector of dengue, has comparable rates of virus dissemination to its primary vector, Ae. aegypti, and when the longer lifespan of Ae. albopictus is considered its competence for dengue virus transmission far exceeds that of Ae. aegypti. Conclusions These results can be used to analyse the effects of temperature and other contributing factors on the expansion of dengue or its Aedes vectors. Our finding that Ae. albopictus has a greater capacity for dengue transmission than Ae. aegypti is contrary to current explanations for the comparative rarity of dengue transmission in established Ae. albopictus populations. This suggests that the limited capacity of Ae. albopictus to transmit DENV is more dependent on its ecology than vector competence. The recommendations, which we

Pseudomonas aeruginosa AES-1 exhibits increased virulence gene expression during chronic infection of cystic fibrosis lung.

PubMed

Naughton, Sharna; Parker, Dane; Seemann, Torsten; Thomas, Torsten; Turnbull, Lynne; Rose, Barbara; Bye, Peter; Cordwell, Stuart; Whitchurch, Cynthia; Manos, Jim

2011-01-01

Pseudomonas aeruginosa, the leading cause of morbidity and mortality in people with cystic fibrosis (CF), adapts for survival in the CF lung through both mutation and gene expression changes. Frequent clonal strains such as the Australian Epidemic Strain-1 (AES-1), have increased ability to establish infection in the CF lung and to superimpose and replace infrequent clonal strains. Little is known about the factors underpinning these properties. Analysis has been hampered by lack of expression array templates containing CF-strain specific genes. We sequenced the genome of an acute infection AES-1 isolate from a CF infant (AES-1R) and constructed a non-redundant micro-array (PANarray) comprising AES-1R and seven other sequenced P. aeruginosa genomes. The unclosed AES-1R genome comprised 6.254Mbp and contained 6957 putative genes, including 338 not found in the other seven genomes. The PANarray contained 12,543 gene probe spots; comprising 12,147 P. aeruginosa gene probes, 326 quality-control probes and 70 probes for non-P. aeruginosa genes, including phage and plant genes. We grew AES-1R and its isogenic pair AES-1M, taken from the same patient 10.5 years later and not eradicated in the intervening period, in our validated artificial sputum medium (ASMDM) and used the PANarray to compare gene expression of both in duplicate. 675 genes were differentially expressed between the isogenic pairs, including upregulation of alginate, biofilm, persistence genes and virulence-related genes such as dihydroorotase, uridylate kinase and cardiolipin synthase, in AES-1M. Non-PAO1 genes upregulated in AES-1M included pathogenesis-related (PAGI-5) genes present in strains PACS2 and PA7, and numerous phage genes. Elucidation of these genes' roles could lead to targeted treatment strategies for chronically infected CF patients.

Pseudomonas aeruginosa AES-1 Exhibits Increased Virulence Gene Expression during Chronic Infection of Cystic Fibrosis Lung

PubMed Central

Naughton, Sharna; Parker, Dane; Seemann, Torsten; Thomas, Torsten; Turnbull, Lynne; Rose, Barbara; Bye, Peter; Cordwell, Stuart; Whitchurch, Cynthia; Manos, Jim

2011-01-01

Pseudomonas aeruginosa, the leading cause of morbidity and mortality in people with cystic fibrosis (CF), adapts for survival in the CF lung through both mutation and gene expression changes. Frequent clonal strains such as the Australian Epidemic Strain-1 (AES-1), have increased ability to establish infection in the CF lung and to superimpose and replace infrequent clonal strains. Little is known about the factors underpinning these properties. Analysis has been hampered by lack of expression array templates containing CF-strain specific genes. We sequenced the genome of an acute infection AES-1 isolate from a CF infant (AES-1R) and constructed a non-redundant micro-array (PANarray) comprising AES-1R and seven other sequenced P. aeruginosa genomes. The unclosed AES-1R genome comprised 6.254Mbp and contained 6957 putative genes, including 338 not found in the other seven genomes. The PANarray contained 12,543 gene probe spots; comprising 12,147 P. aeruginosa gene probes, 326 quality-control probes and 70 probes for non-P. aeruginosa genes, including phage and plant genes. We grew AES-1R and its isogenic pair AES-1M, taken from the same patient 10.5 years later and not eradicated in the intervening period, in our validated artificial sputum medium (ASMDM) and used the PANarray to compare gene expression of both in duplicate. 675 genes were differentially expressed between the isogenic pairs, including upregulation of alginate, biofilm, persistence genes and virulence-related genes such as dihydroorotase, uridylate kinase and cardiolipin synthase, in AES-1M. Non-PAO1 genes upregulated in AES-1M included pathogenesis-related (PAGI-5) genes present in strains PACS2 and PA7, and numerous phage genes. Elucidation of these genes' roles could lead to targeted treatment strategies for chronically infected CF patients. PMID:21935417

Cluster Chemistry in Electron-Poor Ae-Pt-Cd Systems (Ae=Ca, Sr, Ba): (Sr,Ba)Pt2Cd4, Ca6Pt8Cd16, and Its Known Antitype Er6Pd16Sb8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samal, Saroj L.; Gulo, Fakhili; Corbett, John D.

Three new ternary polar intermetallic compounds, cubic Ca6Pt8Cd16, and tetragonal (Sr, Ba)Pt2Cd4 have been discovered during explorations of the Ae–Pt–Cd systems. Cubic Ca6Pt8Cd16 (Fm-3m, Z = 4, a = 13.513(1) Å) contains a 3D array of separate Cd8 tetrahedral stars (TS) that are both face capped along the axes and diagonally bridged by Pt atoms to generate the 3D anionic network Cd8[Pt(1)]6/2[Pt(2)]4/8. The complementary cationic surface of the cell consists of a face-centered cube of Pt(3)@Ca6 octahedra. This structure is an ordered ternary variant of Sc11Ir4 (Sc6Ir8Sc16), a stuffed version of the close relative Na6Au7Cd16, and a network inverse ofmore » the recent Er6Sb8Pd16 (compare Ca6Pt8Cd16). The three groups of elements each occur in only one structural version. The new AePt2Cd4, Ae = Sr, Ba, are tetragonal (P42/mnm,Z = 2, a ≈ 8.30 Å, c ≈ 4.47 Å) and contain chains of edge-sharing Cd4 tetrahedra along c that are bridged by four-bonded Ba/Sr. LMTO-ASA and ICOHP calculation results and comparisons show that the major bonding (Hamilton) populations in Ca6Pt8Cd16 and Er6Sb8Pd16 come from polar Pt–Cd and Pd–Sb interactions, that Pt exhibits larger relativistic contributions than Pd, that characteristic size and orbital differences are most evident for Sb 5s, Pt8, and Pd16, and that some terms remain incomparable, Ca–Cd versus Er–Pd.« less

Star-triangle and star-star relations in statistical mechanics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baxter, R.J.

1997-01-20

The homogeneous three-layer Zamolodchikov model is equivalent to a four-state model on the checkerboard lattice which closely resembles the four-state critical Potts model, but with some of its Boltzmann weights negated. Here the author shows that it satisfies a star-to-reverse-star (or simply star-star) relation, even though they know of no star-triangle relation for this model. For any nearest-neighbor checkerboard model, they show that this star-star relation is sufficient to ensure that the decimated model (where half the spins have been summed over) satisfies a twisted Yang-Baxter relation. This ensures that the transfer matrices of the original model commute in pairs,more » which is an adequate condition for solvability.« less

Processing of N-linked oligosaccharide depends on its location in the anion exchanger, AE1, membrane glycoprotein.

PubMed

Li, J; Quilty, J; Popov, M; Reithmeier, R A

2000-07-01

The human erythrocyte anion exchanger (AE)1 (Band 3) contains a single complex N-linked oligosaccharide that is attached to Asn(642) in the fourth extracellular loop of this polytopic membrane protein, while other isoforms (AE2, AE3 and trout AE1) are N-glycosylated on the preceding extracellular loop. Human AE1 expressed in transfected human embryonic kidney (HEK)-293 or COS-7 cells contained a high-mannose oligosaccharide. The lack of oligosaccharide processing was not due to retention of AE1 in the endoplasmic reticulum since biotinylation assays showed that approx. 30% of the protein was expressed at the cell surface. Moving the N-glycosylation site to the preceding extracellular loop in an AE1 glycosylation mutant (N555) resulted in processing of the oligosaccharide and production of a complex form of AE1. A double N-glycosylation mutant (N555/N642) contained both a high-mannose and a complex oligosaccharide chain. The complex form of the N555 mutant could be biotinylated showing that this form of the glycoprotein was at the cell surface. Pulse-chase experiments showed that the N555 mutant was efficiently converted from a high-mannose to a complex oligosaccharide with a half-time of approx. 4 h, which reflected the time course of trafficking of AE1 from the endoplasmic reticulum to the plasma membrane. The turnover of the complex form of the N555 mutant occurred with a half-life of approx. 15 h. The results show that the oligosaccharide attached to the endogenous site in extracellular loop 4 in human AE1 is not processed in HEK-293 or COS-7 cells, while the oligosaccharide attached to the preceding loop is converted into the complex form.

Hypolipidemic effects of starch and γ-oryzanol from wx/ae double-mutant rice on BALB/c.KOR-Apoe(shl) mice.

PubMed

Nakaya, Makoto; Shojo, Aiko; Hirai, Hiroaki; Matsumoto, Kenji; Kitamura, Shinichi

2013-01-01

waxy/amylose-extender (wx/ae) double-mutant japonica rice (Oryza sativa L.) produces resistant starch (RS) and a large amount of γ-oryzanol. Our previous study has shown the hypolipidemic effect of wx/ae brown rice on mice. To identify the functional constituents of the hypolipidemic activity in wx/ae rice, we prepared pure wx/ae starch and γ-oryzanol from wx/ae rice and investigated their effect on the lipid metabolism in BALB/c.KOR/Stm Slc-Apoe(shl) mice. The mice were fed for 3 weeks a diet containing non-mutant rice starch, non-mutant rice starch plus γ-oryzanol, wx/ae starch, or wx/ae starch plus γ-oryzanol. γ-Oryzanol by itself had no effect on the lipid metabolism, and wx/ae starch prevented an accumulation of triacylglycerol (TAG) in the liver. Interestingly, the combination of wx/ae starch plus γ-oryzanol not only prevented a TAG accumulation in the liver, but also partially suppressed the rise in plasma TAG concentration, indicating that wx/ae starch and γ-oryzanol could have a synergistic effect on the lipid metabolism.

Crustal stress, seismicity, acoustic emission (AE), and tectonics: the Kefallinì;a (Greece) case study

NASA Astrophysics Data System (ADS)

Gregori, G. P.; Poscolieri, M.; Paparo, G.; Ventrice, G.; de Simone, S.; Rafanelli, C.

2009-04-01

New inferences - confirming previous results (see references)- are presented dealing with a few years Acoustic Emission (AE) records collected at Kefallinìa (Ionian Islands, Greece). A physical distinction between HF (high frequency) vs. LF (low frequency) AE is required. Step-wise changes of the AE underground conductivity are evidenced, and can be suitably handled. "Smooth" results concern (i) the annual variation, (ii) some long-lasting stress "solitons" crossing through the area, and (iii) tidal effects. In particular, every AE station can be operated like a monitoring station both for Earth's tides and for the free oscillations of the Earth. In addition, Kefallinìa exhibits a much peculiar groundwater circulation, in which conduit flow is dominant, that originates a specific (and unique) AE effect. By means of AE time-series analysis, "extreme" or "catastrophic" events can be also monitored and possibly related to relevant tectonic occurrences (either earthquakes, or maybe other occasional phenomena). They can be investigated, and have a regional - rather than local - character. Therefore, every interpretation based on a single station record - being biased by some arbitrariness - can only result indicative. A standardized procedure and software is proposed for routine AE data handling and analysis. References.: Lagios et al., 2004. In Proc. SCI 2004 (The 8th World Multi-Conference on Systemics, Cybernetics and Informatic), Orlando, Florida, July 1004, 6 pp. Poscolieri et al., 2006. In. G. Cello and B. D. Malamud, (eds), 2006. Geol. Soc. London, Special Publ., 261, 63-78. Poscolieri et al., 2006a. Nat. Hazards Earth Syst. Sci., 6, 961-971.

Validation of the French version of the Acceptability E-scale (AES) for mental E-health systems.

PubMed

Micoulaud-Franchi, Jean-Arthur; Sauteraud, Alain; Olive, Jérôme; Sagaspe, Patricia; Bioulac, Stéphanie; Philip, Pierre

2016-03-30

Despite the increasing use of E-health systems for mental-health organizations, there is a lack of psychometric tools to evaluate their acceptability by patients with mental disorders. Thus, this study aimed to translate and validate a French version of the Acceptability E-scale (AES), a 6-item self-reported questionnaire that evaluates the extent to which patients find E-health systems acceptable. A forward-backward translation of the AES was performed. The psychometric properties of the French AES version, with construct validity, internal structural validity and external validity (Pearson's coefficient between AES scores and depression symptoms on the Beck Depression Inventory II) were analyzed. In a sample of 178 patients (mean age=46.51 years, SD=12.91 years), the validation process revealed satisfactory psychometric properties: factor analysis revealed two factors: "Satisfaction" (3 items) and "Usability" (3 items) and Cronbach's alpha was 0.7. No significant relation was found between AES scores and depression symptoms. The French version of the AES revealed a two-factor scale that differs from the original version. In line with the importance of acceptability in mental health and with a view to E-health systems for patients with mental disorders, the use of the AES in psychiatry may provide important information on acceptability (i.e., satisfaction and usability). Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Adverse Effects (AEs) of Topical NSAIDs in Older Adults with Osteoarthritis (OA): a Systematic Review of the Literature

PubMed Central

Makris, UE.; Kohler, MJ.; Fraenkel, L.

2010-01-01

Objective To systematically review the literature on reported adverse effects (AEs) associated with topical NSAID use in older adults with osteoarthritis (OA). Methods A systematic search of Medline (1950 to November 2009), Scopus, Embase, Web of Science, Cochrane databases, Dissertation and American College of Rheumatology Meeting Abstracts was performed to identify original randomized controlled trials, case reports, observational studies, editorials or dissertations reporting AEs from topical NSAIDs in older adults with OA. Information was sought on study and participant characteristics, detailed recording of application site and systemic AEs as well as withdrawals due to AEs. Results The initial search yielded 953 articles of which 19 met eligibility criteria. Subjects receiving topical NSAIDs reported up to 39.3% application site AEs, and up to 17.5% systemic AEs. Five cases of warfarin potentiation with topical agents were reported; 1 resulting in gastrointestinal bleeding. In formal trials, the withdrawal rate from AEs ranged from 0-21% in the topical agents, 0-25% in the oral NSAIDs, and 0-16% in the placebo group. Conclusion In summary, although topical NSAIDs are safer than oral NSAIDs (fewer severe gastrointestinal AEs), a substantial proportion of older adults report systemic AEs with topical agents. Moreover, the withdrawal rate due to AEs with topical agents is comparable to that of oral NSAIDs. Given the safety profile and withdrawal rates described in this study, further data are needed to determine the incremental benefits of topical NSAIDs compared to other treatment modalities in older adults with OA. PMID:20360183

A Three-dimensional Simulation of a Magnetized Accretion Disk: Fast Funnel Accretion onto a Weakly Magnetized Star

NASA Astrophysics Data System (ADS)

Takasao, Shinsuke; Tomida, Kengo; Iwasaki, Kazunari; Suzuki, Takeru K.

2018-04-01

We present the results of a global, three-dimensional magnetohydrodynamics simulation of an accretion disk with a rotating, weakly magnetized central star. The disk is threaded by a weak, large-scale poloidal magnetic field, and the central star has no strong stellar magnetosphere initially. Our simulation investigates the structure of the accretion flows from a turbulent accretion disk onto the star. The simulation reveals that fast accretion onto the star at high latitudes occurs even without a stellar magnetosphere. We find that the failed disk wind becomes the fast, high-latitude accretion as a result of angular momentum exchange mediated by magnetic fields well above the disk, where the Lorentz force that decelerates the rotational motion of gas can be comparable to the centrifugal force. Unlike the classical magnetospheric accretion scenario, fast accretion streams are not guided by magnetic fields of the stellar magnetosphere. Nevertheless, the accretion velocity reaches the free-fall velocity at the stellar surface due to the efficient angular momentum loss at a distant place from the star. This study provides a possible explanation why Herbig Ae/Be stars whose magnetic fields are generally not strong enough to form magnetospheres also show indications of fast accretion. A magnetically driven jet is not formed from the disk in our model. The differential rotation cannot generate sufficiently strong magnetic fields for the jet acceleration because the Parker instability interrupts the field amplification.

A high voltage power supply for the AE-C and D low energy electron experiment

NASA Technical Reports Server (NTRS)

Gillis, J. A.

1974-01-01

A description is given of the electrical and mechanical design and operation of high voltage power supplies for space flight use. The supply was used to generate the spiraltron high voltage for low energy electron experiment on AE-C and D. Two versions of the supply were designed and built; one design is referred to as the low power version (AE-C) and the other as the high power version (AE-D). Performance is discussed under all operating conditions.

19 CFR 192.12 - Criteria for denial of applications requesting AES post-departure (Option 4) filing status...

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 2 2012-04-01 2012-04-01 false Criteria for denial of applications requesting AES...) EXPORT CONTROL Filing of Export Information Through the Automated Export System (AES) § 192.12 Criteria for denial of applications requesting AES post-departure (Option 4) filing status; appeal procedures...

19 CFR 192.12 - Criteria for denial of applications requesting AES post-departure (Option 4) filing status...

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 2 2011-04-01 2011-04-01 false Criteria for denial of applications requesting AES...) EXPORT CONTROL Filing of Export Information Through the Automated Export System (AES) § 192.12 Criteria for denial of applications requesting AES post-departure (Option 4) filing status; appeal procedures...

19 CFR 192.12 - Criteria for denial of applications requesting AES post-departure (Option 4) filing status...

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 2 2014-04-01 2014-04-01 false Criteria for denial of applications requesting AES...) EXPORT CONTROL Filing of Export Information Through the Automated Export System (AES) § 192.12 Criteria for denial of applications requesting AES post-departure (Option 4) filing status; appeal procedures...

19 CFR 192.12 - Criteria for denial of applications requesting AES post-departure (Option 4) filing status...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 2 2010-04-01 2010-04-01 false Criteria for denial of applications requesting AES...) EXPORT CONTROL Filing of Export Information Through the Automated Export System (AES) § 192.12 Criteria for denial of applications requesting AES post-departure (Option 4) filing status; appeal procedures...

19 CFR 192.12 - Criteria for denial of applications requesting AES post-departure (Option 4) filing status...

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 2 2013-04-01 2013-04-01 false Criteria for denial of applications requesting AES...) EXPORT CONTROL Filing of Export Information Through the Automated Export System (AES) § 192.12 Criteria for denial of applications requesting AES post-departure (Option 4) filing status; appeal procedures...

Using a Delphi approach to develop a strategy for A&E in defence nursing.

PubMed

Kenward, Gary; Berry, Andy; Despres, Julian; McLeod, Judith

The Armed Forces has seen an increase in the number of operational deployments overseas and a greater demand for Accident and Emergency (A&E) trained nurses. This article describes a modified Delphi study used to contribute to the development of a strategy for emergency nursing in the Defence Nursing Services. Twenty-eight A&E specialists took part and the key issues raised were recruitment and retention, staff development, new roles, research priorities, increased internal recruitment of A&E nurses to meet operational demands, and the need for a structured career pathway to help retention. The most pressing areas requiring research were evaluation of the nurse practitioner role, clinical competencies and managing heat injuries in the operational setting. The modified Delphi study provided a valuable and detailed insight into the challenges and aspirations of the military A&E nursing cadre and has assisted in developing a strategy for emergency nursing.

Characterization of the aes gene of Escherichia coli encoding an enzyme with esterase activity.

PubMed Central

Peist, R; Koch, A; Bolek, P; Sewitz, S; Kolbus, T; Boos, W

1997-01-01

malQ mutants of Escherichia coli lacking amylomaltase cannot grow on maltose. They express the maltose system constitutively and are sensitive to maltose when grown on another carbon source. In an attempt to isolate a multicopy suppressor that would result in growth on maltose, we transformed a malQ mutant with a gene bank of E. coli DNA which had been digested with Sau3a and cloned in pBR322. We screened the transformants on MacConkey maltose plates. A colony was isolated that appeared to be resistant to maltose and was pink on these plates, but it was still unable to grow on minimal medium with maltose as the carbon source. The plasmid was isolated, and the gene causing this phenotype was characterized. The deduced amino acid sequence of the encoded protein shows homology to that of lipases and esterases. We termed the gene aes, for acetyl esterase. Extracts of cells harboring plasmid-encoded aes under its own promoter exhibit a fivefold higher capacity to hydrolyze p-nitrophenyl acetate than do extracts of cells of plasmid-free strains. Similarly, strains harboring plasmid-encoded aes are able to grow on triacetyl glycerol (triacetin) whereas the plasmid-free strains are not. The expression of plasmid-encoded aes resulted in strong repression of the maltose transport genes in malT+ strains (10-fold reduction), but not in a malT(Con) strain which is independent of the inducer. Also, overproduction of MalT counteracted the Aes-dependent repression, indicating a direct interaction between MalT and Aes. PMID:9401025

Recent results from the SIMECA code and VLTI observations

NASA Astrophysics Data System (ADS)

Meilland, A.; Stee, Ph.

We present recent results on active hot stars using the first VLTI/MIDI and VLTI/AMBER observations, and the SIMECA code developed by Stee (1994). α Arae was the first classical Be star observed with MIDI (June 2003) and AMBER (February 2005). The size of its circumstellar envelope was measured and thanks to the spectrally-resolved interferometric AMBER observations, we were able, for the first time to evidence the Keplerian rotation of the circumstellar disc. MWC 297 is one of the brightest Herbig Be star, and it was then observed during the first commissioning run of AMBER in May 2004. The data obtained were good enough to allow us to infer the accretion disc extension, as well as to put strong constraints on the stellar wind geometry and kinematics.

Functional characterization and modified rescue of novel AE1 mutation R730C associated with overhydrated cation leak stomatocytosis.

PubMed

Stewart, Andrew K; Kedar, Prabhakar S; Shmukler, Boris E; Vandorpe, David H; Hsu, Ann; Glader, Bertil; Rivera, Alicia; Brugnara, Carlo; Alper, Seth L

2011-05-01

We report the novel, heterozygous AE1 mutation R730C associated with dominant, overhydrated, cation leak stomatocytosis and well-compensated anemia. Parallel elevations of red blood cell cation leak and ouabain-sensitive Na(+) efflux (pump activity) were apparently unaccompanied by increased erythroid cation channel-like activity, and defined ouabain-insensitive Na(+) efflux pathways of nystatin-treated cells were reduced. Epitope-tagged AE1 R730C at the Xenopus laevis oocyte surface exhibited severely reduced Cl(-) transport insensitive to rescue by glycophorin A (GPA) coexpression or by methanethiosulfonate (MTS) treatment. AE1 mutant R730K preserved Cl(-) transport activity, but R730 substitution with I, E, or H inactivated Cl(-) transport. AE1 R730C expression substantially increased endogenous oocyte Na(+)-K(+)-ATPase-mediated (86)Rb(+) influx, but ouabain-insensitive flux was minimally increased and GPA-insensitive. The reduced AE1 R730C-mediated sulfate influx did not exhibit the wild-type pattern of stimulation by acidic extracellular pH (pH(o)) and, unexpectedly, was partially rescued by exposure to sodium 2-sulfonatoethyl methanethiosulfonate (MTSES) but not to 2-aminoethyl methanethiosulfonate hydrobromide (MTSEA) or 2-(trimethylammonium)ethyl methanethiosulfonate bromide (MTSET). AE1 R730E correspondingly exhibited acid pH(o)-stimulated sulfate uptake at rates exceeding those of wild-type AE1 and AE1 R730K, whereas mutants R730I and R730H were inactive and pH(o) insensitive. MTSES-treated oocytes expressing AE1 R730C and untreated oocytes expressing AE1 R730E also exhibited unprecedented stimulation of Cl(-) influx by acid pH(o). Thus recombinant cation-leak stomatocytosis mutant AE1 R730C exhibits severely reduced anion transport unaccompanied by increased Rb(+) and Li(+) influxes. Selective rescue of acid pH(o)-stimulated sulfate uptake and conferral of acid pH(o)-stimulated Cl(-) influx, by AE1 R730E and MTSES-treated R730C, define residue R730 as

Neutron Stars and NuSTAR

NASA Astrophysics Data System (ADS)

Bhalerao, Varun

2012-05-01

My thesis centers around the study of neutron stars, especially those in massive binary systems. To this end, it has two distinct components: the observational study of neutron stars in massive binaries with a goal of measuring neutron star masses and participation in NuSTAR, the first imaging hard X-ray mission, one that is extremely well suited to the study of massive binaries and compact objects in our Galaxy. The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission that will carry the first focusing high energy X-ray telescope to orbit. NuSTAR has an order-of-magnitude better angular resolution and has two orders of magnitude higher sensitivity than any currently orbiting hard X-ray telescope. I worked to develop, calibrate, and test CdZnTe detectors for NuSTAR. I describe the CdZnTe detectors in comprehensive detail here - from readout procedures to data analysis. Detailed calibration of detectors is necessary for analyzing astrophysical source data obtained by the NuSTAR. I discuss the design and implementation of an automated setup for calibrating flight detectors, followed by calibration procedures and results. Neutron stars are an excellent probe of fundamental physics. The maximum mass of a neutron star can put stringent constraints on the equation of state of matter at extreme pressures and densities. From an astrophysical perspective, there are several open questions in our understanding of neutron stars. What are the birth masses of neutron stars? How do they change in binary evolution? Are there multiple mechanisms for the formation of neutron stars? Measuring masses of neutron stars helps answer these questions. Neutron stars in high-mass X-ray binaries have masses close to their birth mass, providing an opportunity to disentangle the role of "nature" and "nurture" in the observed mass distributions. In 2006, masses had been measured for only six such objects, but this small sample showed the greatest diversity in masses

A method for reduction of Acoustic Emission (AE) data with application in machine failure detection and diagnosis

NASA Astrophysics Data System (ADS)

Vicuña, Cristián Molina; Höweler, Christoph

2017-12-01

The use of AE in machine failure diagnosis has increased over the last years. Most AE-based failure diagnosis strategies use digital signal processing and thus require the sampling of AE signals. High sampling rates are required for this purpose (e.g. 2 MHz or higher), leading to streams of large amounts of data. This situation is aggravated if fine resolution and/or multiple sensors are required. These facts combine to produce bulky data, typically in the range of GBytes, for which sufficient storage space and efficient signal processing algorithms are required. This situation probably explains why, in practice, AE-based methods consist mostly in the calculation of scalar quantities such as RMS and Kurtosis, and the analysis of their evolution in time. While the scalar-based approach offers the advantage of maximum data reduction; it has the disadvantage that most part of the information contained in the raw AE signal is lost unrecoverably. This work presents a method offering large data reduction, while keeping the most important information conveyed by the raw AE signal, useful for failure detection and diagnosis. The proposed method consist in the construction of a synthetic, unevenly sampled signal which envelopes the AE bursts present on the raw AE signal in a triangular shape. The constructed signal - which we call TriSignal - also permits the estimation of most scalar quantities typically used for failure detection. But more importantly, it contains the information of the time of occurrence of the bursts, which is key for failure diagnosis. Lomb-Scargle normalized periodogram is used to construct the TriSignal spectrum, which reveals the frequency content of the TriSignal and provides the same information as the classic AE envelope. The paper includes application examples in planetary gearbox and low-speed rolling element bearing.

19 CFR 4.76 - Procedures and responsibilities of carriers filing outbound vessel manifest information via the AES.

Code of Federal Regulations, 2012 CFR

2012-04-01

... outbound vessel manifest information via the AES. 4.76 Section 4.76 Customs Duties U.S. CUSTOMS AND BORDER... manifest information via the AES. (a) The sea carrier's module. The Sea Carrier's Module is a component of the Automated Export System (AES) (see, part 192, subpart B, of this chapter) that allows for the...

19 CFR 4.76 - Procedures and responsibilities of carriers filing outbound vessel manifest information via the AES.

Code of Federal Regulations, 2014 CFR

2014-04-01

... outbound vessel manifest information via the AES. 4.76 Section 4.76 Customs Duties U.S. CUSTOMS AND BORDER... manifest information via the AES. (a) The sea carrier's module. The Sea Carrier's Module is a component of the Automated Export System (AES) (see, part 192, subpart B, of this chapter) that allows for the...

19 CFR 4.76 - Procedures and responsibilities of carriers filing outbound vessel manifest information via the AES.

Code of Federal Regulations, 2011 CFR

2011-04-01

... outbound vessel manifest information via the AES. 4.76 Section 4.76 Customs Duties U.S. CUSTOMS AND BORDER... manifest information via the AES. (a) The sea carrier's module. The Sea Carrier's Module is a component of the Automated Export System (AES) (see, part 192, subpart B, of this chapter) that allows for the...

19 CFR 4.76 - Procedures and responsibilities of carriers filing outbound vessel manifest information via the AES.

Code of Federal Regulations, 2013 CFR

2013-04-01

... outbound vessel manifest information via the AES. 4.76 Section 4.76 Customs Duties U.S. CUSTOMS AND BORDER... manifest information via the AES. (a) The sea carrier's module. The Sea Carrier's Module is a component of the Automated Export System (AES) (see, part 192, subpart B, of this chapter) that allows for the...

19 CFR 4.76 - Procedures and responsibilities of carriers filing outbound vessel manifest information via the AES.

Code of Federal Regulations, 2010 CFR

2010-04-01

... outbound vessel manifest information via the AES. 4.76 Section 4.76 Customs Duties U.S. CUSTOMS AND BORDER... manifest information via the AES. (a) The sea carrier's module. The Sea Carrier's Module is a component of the Automated Export System (AES) (see, part 192, subpart B, of this chapter) that allows for the...

IrAE – an asparaginyl endopeptidase (legumain) in the gut of the hard tick Ixodes ricinus

PubMed Central

Sojka, Daniel; Hajdušek, Ondřej; Dvořák, Jan; Sajid, Mohammed; Franta, Zdeněk; Schneider, Eric L.; Craik, Charles S.; Vancová, Marie; Burešová, Veronika; Bogyo, Matthew; Sexton, Kelly B.; McKerrow, James H.; Caffrey, Conor R.; Kopáček, Petr

2008-01-01

Ticks are ectoparasitic blood-feeders and important vectors for pathogens including arboviruses, rickettsiae, spirochetes and protozoa. As obligate blood-feeders, one possible strategy to retard disease transmission is disruption of the parasite’s ability to digest host proteins. However, the constituent peptidases in the parasite gut and their potential interplay in the digestion of the blood meal are poorly understood. We have characterized a novel asparaginyl endopeptidase (legumain) from the hard tick Ixodes ricinus (termed IrAE), which is the first such characterization of a clan CD family C13 cysteine peptidase (protease) in arthropods. By RT-PCR of different tissues, IrAE mRNA was only expressed in the tick gut. Indirect immunofluorescence and electron microscopy localized IrAE in the digestive vesicles of gut cells and within the peritrophic matrix. IrAE was functionally expressed in Pichia pastoris and reacted with a specific peptidyl fluorogenic substrate, and acyloxymethyl ketone and aza-asparagine Michael acceptor inhibitors. IrAE activity was unstable at pH ≥ 6.0 and was shown to have a strict specificity for asparagine at P1 using a positional scanning synthetic combinatorial library. The enzyme hydrolyzed protein substrates with a pH optimum of 4.5, consistent with the pH of gut cell digestive vesicles. Thus, IrAE cleaved the major protein of the blood meal, hemoglobin, to a predominant peptide of 4 kDa. Also, IrAE trans-processed and activated the zymogen form of Schistosoma mansoni cathepsin B1 – an enzyme contributing to hemoglobin digestion in the gut of that bloodfluke. The possible functions of IrAE in the gut digestive processes of I. ricinus are compared with those suggested for other hematophagous parasites. PMID:17336985

Clinical and molecular genetic features of Hb H and AE Bart's diseases in central Thai children.

PubMed

Traivaree, Chanchai; Boonyawat, Boonchai; Monsereenusorn, Chalinee; Rujkijyanont, Piya; Photia, Apichat

2018-01-01

α-Thalassemia, one of the major thalassemia types in Thailand, is caused by either deletion or non-deletional mutation of one or both α-globin genes. Inactivation of three α-globin genes causes hemoglobin H (Hb H) disease, and the combination of Hb H disease with heterozygous hemoglobin E (Hb E) results in AE Bart's disease. This study aimed to characterize the clinical and hematological manifestations of 76 pediatric patients with Hb H and AE Bart's diseases treated at Phramongkutklao Hospital, a tertiary care center for thalassemia patients in central Thailand. Seventy-six unrelated pediatric patients, 58 patients with Hb H disease and 18 patients with AE Bart's disease, were enrolled in this study. Their clinical presentations, transfusion requirement, laboratory findings, and mutation analysis were retrospectively reviewed and analyzed. A total of 76 pediatric patients with Hb H and AE Bart's diseases who mainly lived in central Thailand were included in this study. The clinical severities of patients with non-deletional mutations were more severe than those with deletional mutations. Eighty-six percent of patients with non-deletional AE Bart's disease required more blood transfusion compared to 12.5% of patients with deletional AE Bart's disease. Non-deletional AE Bart's disease also had a history of urgent blood transfusion with the average of 6±0.9 times compared to 1±0.3 times in patients with deletional Hb H disease. The difference was statistically significant. This study revealed the differences in clinical spectrum between patients with Hb H disease and those with AE Bart's disease in central Thailand. The differentiation of α-thalassemia is essential for appropriate management of patients. The molecular diagnosis is useful for diagnostic confirmation and genotype-phenotype correlation.

Observations of Circumstellar Disks with Infrared Interferometry

NASA Technical Reports Server (NTRS)

Akeson, Rachel

2008-01-01

Star formation is arguably the area of astrophysics in which infrared interferometry has had the biggest impact. The optically thick portion of T Tauri and Herbig Ae/Be disks DO NOT extend to a few stellar radii of the stellar surface. Emission is coming from near the dust sublimation radius, but not all from a single radius. The Herbig Ae stars can be either flared or self-shadowed but very massive (early Be) stars are geometrically thin. The Herbig Ae stars can be either flared or self-shadowed but very massive (early Be) stars are geometrically thin. Observational prospects are rapidly improving: a) Higher spectral resolution will allow observations of the gas: jets, winds, accretion. b) Closure phase and imaging will help eliminate model uncertainties/dependencies.

Monte Carlo simulation of star/linear and star/star blends with chemically identical monomers

NASA Astrophysics Data System (ADS)

Theodorakis, P. E.; Avgeropoulos, A.; Freire, J. J.; Kosmas, M.; Vlahos, C.

2007-11-01

The effects of chain size and architectural asymmetry on the miscibility of blends with chemically identical monomers, differing only in their molecular weight and architecture, are studied via Monte Carlo simulation by using the bond fluctuation model. Namely, we consider blends composed of linear/linear, star/linear and star/star chains. We found that linear/linear blends are more miscible than the corresponding star/star mixtures. In star/linear blends, the increase in the volume fraction of the star chains increases the miscibility. For both star/linear and star/star blends, the miscibility decreases with the increase in star functionality. When we increase the molecular weight of linear chains of star/linear mixtures the miscibility decreases. Our findings are compared with recent analytical and experimental results.

MMR immunisation status among Dublin paediatric A&E attenders.

PubMed

Murphy, A W; Power, R; Kinlen, D M; Johnson, Z

1994-01-01

The objectives of this study were to establish the need for opportunistic MMR immunisation among paediatric A&E attenders to the three Dublin paediatric hospitals and to examine the relationship between immunisation status and socioeconomic factors. Design was that of a two month cross sectional study. Survey data was then compared with information on the Eastern Health Board (EHB) records system. Small area and multiple regression analysis of socioeconomic factors derived from participants addresses was also performed. Subjects were 337 children who attended these departments and were aged between fifteen months and five years. For 66% of cases there was a history of MMR immunisation, 30% gave a negative history and 4% did not know. Of those giving a negative history, one third said immunisation had been omitted for no specific reason. EHB records suggested that 39% were immunised, 41% were not and 20% were not on file. Eligibility for the GMS was not associated with failure to immunise. Small area and multiple regression analysis showed little association between immunisation uptake and socioeconomic factors. An opportunistic MMR immunisation policy in A&E Departments would make an important contribution to increasing overall uptake figures. Parental knowledge of the implications of measles and the effectiveness of immunisation needs to be improved. Computerised child health systems must have high data quality standards and access to these systems should be made available in A&E departments.

The effect of CFRP on retrofitting of damaged HSRC beams using AE technique

NASA Astrophysics Data System (ADS)

Soffian Noor, M. S.; Noorsuhada, M. N.

2017-12-01

This paper presents the effect of carbon fibre reinforced polymer (CFRP) on retrofitted high strength reinforced concrete (HSRC) beams using acoustic emission (AE) technique. Two RC beam parameters were prepared. The first was the control beam which was undamaged HSRC beam. The second was the damaged HSRC beam retrofitted with CFRP on the soffit. The main objective of this study is to assess the crack modes of HSRC beams using AE signal strength. The relationship between signal strength, load and time were analysed and discussed. The crack pattern observed from the visual observation was also investigated. HSRC beam retrofitted with CFRP produced high signal strength compared to control beam. It demonstrates the effect of the AE signal strength for interpretation and prediction of failure modes that might occur in the beam specimens.

ETV VR/VS Magee Scientific Model AE33 Aethalometer

EPA Science Inventory

The objective of the ETV AMS Center is to verify the performance characteristics of environmental monitoring technologies for air, water, and soil. This report provides results for the verification testing of the Magee Scientific Model AE33 Aethalometer.

The circumstellar environments of dusty main sequence stars

NASA Astrophysics Data System (ADS)

Gebrim, Antonio S. Hales

-light images of dust-disks around dust excess stars. This technique allows one to automatically suppress the unpolarised light from the central star, increasing the dynamic range for detecting polarised light scattered by the dust present in circumstellar discs. The detections of extended disks around the classical T Tauri star TW Hya and the Herbig Ac star HD 169142 are reported, as well as the strong but spatially unresolved polarization signals measured toward two other Herbig Ae stars. Monte Carlo scattering simulations are used to fit the J-, H- and K-band polarization images of the disk around TW Hya, providing new constraints on the geometry of TW Hya's disk. The third part of this thesis is dedicated to studying the gas content and dynamics around dust-excess stars. The evolution of circumstellar gas is thought to be strongly linked to the formation of gaseous giant planets similar to Jupiter, Saturn and most currently known extra-solar planets. However, the timescales over which circumstellar gas discs dissipate remains poorly constrained, mainly due to the observational difficulties associated with detecting small amounts of circumstellar gas. An analysis of high-resolution (R 50 000) optical spectroscopic data of a sample of 'Vega-like' candidates from the catalogue of Mannings & Barlow (1998) is presented. Analysis of the stellar spectra allows one to search for narrow absorption features due to circumstellar gas and possible Falling Evaporating Bodies, similar to the ones seen in the (3 Pictoris system. None of the stars from this sample show emission line activity in either Ha, Ca II or Na I, indicating that accretion of material onto the stars has ceased and suggesting they are true main sequence Vega-like stars. Four stars were found to exhibit narrow absorption features near the cores of the photospheric Ca II and Na I D lines, with HD 110058 being the strongest candidate to host a (3 Pictoris-like gas disk. If confirmed, HD 110058 would represent the Vega

A Comparison of Van Allen Belt Radiation Environment Modeling Programs: AE8/AP8 Legacy, AE9/AP9, and SPENVIS

NASA Technical Reports Server (NTRS)

Reed, Evan; Pellish, Jonathan

2016-01-01

In the space surrounding Earth there exists an active radiation environment consisting mostly of electrons and protons that have been trapped by Earths magnetic field. This radiation, also known as the Van Allen Belts, has the potential to damage man-made satellites in orbit; thus, proper precautions must be taken to shield NASA assets from this phenomenon. Data on the Van Allen Belts has been collected continuously by a multitude of space-based instruments since the beginning of space exploration. Subsequently, using theory to fill in the gaps in the collected data, computer models have been developed that take in the orbital information of a hypothetical mission and output the expected particle fluence and flux for that orbit. However, as new versions of the modeling system are released, users are left wondering how the new version differs from the old. Therefore, we performed a comparison of three different editions of the modeling system: AE8/AP8 (legacy), which is included in the model 9 graphical user interface as an option for ones calculations, AE9/AP9, and the Space Environment Information System (SPENVIS), which is an online-based form of AE8/AP8 developed by NASA and the European Space Agency that changed the code to allow the program to extrapolate data to predict fluence and flux at higher energies. Although this evaluation is still ongoing, it is predicted that the model 8 (legacy) and SPENVIS version will have identical outputs with the exception of the extended energy levels from SPENVIS, while model 9 will provide different fluences than model 8 based on additional magnetic field descriptions and on-orbit data.

Realization and optimization of AES algorithm on the TMS320DM6446 based on DaVinci technology

NASA Astrophysics Data System (ADS)

Jia, Wen-bin; Xiao, Fu-hai

2013-03-01

The application of AES algorithm in the digital cinema system avoids video data to be illegal theft or malicious tampering, and solves its security problems. At the same time, in order to meet the requirements of the real-time, scene and transparent encryption of high-speed data streams of audio and video in the information security field, through the in-depth analysis of AES algorithm principle, based on the hardware platform of TMS320DM6446, with the software framework structure of DaVinci, this paper proposes the specific realization methods of AES algorithm in digital video system and its optimization solutions. The test results show digital movies encrypted by AES128 can not play normally, which ensures the security of digital movies. Through the comparison of the performance of AES128 algorithm before optimization and after, the correctness and validity of improved algorithm is verified.

Wireless AE Event and Environmental Monitoring for Wind Turbine Blades at Low Sampling Rates

NASA Astrophysics Data System (ADS)

Bouzid, Omar M.; Tian, Gui Y.; Cumanan, K.; Neasham, J.

Integration of acoustic wireless technology in structural health monitoring (SHM) applications introduces new challenges due to requirements of high sampling rates, additional communication bandwidth, memory space, and power resources. In order to circumvent these challenges, this chapter proposes a novel solution through building a wireless SHM technique in conjunction with acoustic emission (AE) with field deployment on the structure of a wind turbine. This solution requires a low sampling rate which is lower than the Nyquist rate. In addition, features extracted from aliased AE signals instead of reconstructing the original signals on-board the wireless nodes are exploited to monitor AE events, such as wind, rain, strong hail, and bird strike in different environmental conditions in conjunction with artificial AE sources. Time feature extraction algorithm, in addition to the principal component analysis (PCA) method, is used to extract and classify the relevant information, which in turn is used to classify or recognise a testing condition that is represented by the response signals. This proposed novel technique yields a significant data reduction during the monitoring process of wind turbine blades.

AML1/ETO induces self-renewal in hematopoietic progenitor cells via the Groucho-related amino-terminal AES protein.

PubMed

Steffen, Björn; Knop, Markus; Bergholz, Ulla; Vakhrusheva, Olesya; Rode, Miriam; Köhler, Gabriele; Henrichs, Marcel-Philipp; Bulk, Etmar; Hehn, Sina; Stehling, Martin; Dugas, Martin; Bäumer, Nicole; Tschanter, Petra; Brandts, Christian; Koschmieder, Steffen; Berdel, Wolfgang E; Serve, Hubert; Stocking, Carol; Müller-Tidow, Carsten

2011-04-21

The most frequent translocation t(8;21) in acute myeloid leukemia (AML) generates the chimeric AML1/ETO protein, which blocks differentiation and induces self-renewal in hematopoietic progenitor cells. The underlying mechanisms mediating AML1/ETO-induced self-renewal are largely unknown. Using expression microarray analysis, we identified the Groucho-related amino-terminal enhancer of split (AES) as a consistently up-regulated AML1/ETO target. Elevated levels of AES mRNA and protein were confirmed in AML1/ETO-expressing leukemia cells, as well as in other AML specimens. High expression of AES mRNA or protein was associated with improved survival of AML patients, even in the absence of t(8;21). On a functional level, knockdown of AES by RNAi in AML1/ETO-expressing cell lines inhibited colony formation. Similarly, self-renewal induced by AML1/ETO in primary murine progenitors was inhibited when AES was decreased or absent. High levels of AES expression enhanced formation of immature colonies, serial replating capacity of primary cells, and colony formation in colony-forming unit-spleen assays. These findings establish AES as a novel AML1/ETO-induced target gene that plays an important role in the self-renewal phenotype of t(8;21)-positive AML.

Draft Genome Sequence of Brevibacterium linens AE038-8, an Extremely Arsenic-Resistant Bacterium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maizel, Daniela; Utturkar, Sagar M.; Brown, Steven D.

To understand the arsenic biogeocycles in the groundwaters at Tucumán, Argentina, we isolated Brevibacterium linens sp. strain AE38-8, obtained from arsenic-contaminated well water. This strain is extremely resistant to arsenicals and has arsenic resistance (ars) genes in its genome. Here, we report the draft genome sequence of B. linens AE38-8.

Draft Genome Sequence of Brevibacterium linens AE038-8, an Extremely Arsenic-Resistant Bacterium

DOE PAGES

Maizel, Daniela; Utturkar, Sagar M.; Brown, Steven D.; ...

2015-04-16

To understand the arsenic biogeocycles in the groundwaters at Tucumán, Argentina, we isolated Brevibacterium linens sp. strain AE38-8, obtained from arsenic-contaminated well water. This strain is extremely resistant to arsenicals and has arsenic resistance (ars) genes in its genome. Here, we report the draft genome sequence of B. linens AE38-8.

Degradability, biocompatibility, and osteogenesis of biocomposite scaffolds containing nano magnesium phosphate and wheat protein both in vitro and in vivo for bone regeneration.

PubMed

Xia, Yan; Zhou, Panyu; Wang, Fei; Qiu, Chao; Wang, Panfeng; Zhang, Yuntong; Zhao, Liming; Xu, Shuogui

2016-01-01

In this study, bioactive scaffold of nano magnesium phosphate (nMP)/wheat protein (WP) composite (MWC) was fabricated. The results revealed that the MWC scaffolds had interconnected not only macropores (sized 400-600 μm) but also micropores (sized 10-20 μm) on the walls of macropores. The MWC scaffolds containing 40 w% nMP had an appropriate degradability in phosphate-buffered saline and produced a weak alkaline microenvironment. In cell culture experiments, the results revealed that the MWC scaffolds significantly promoted the MC3T3-E1 cell proliferation, differentiation, and growth into the scaffolds. The results of synchrotron radiation microcomputed tomography and analysis of the histological sections of the in vivo implantation revealed that the MWC scaffolds evidently improved the new bone formation and bone defects repair as compared with WP scaffolds. Moreover, it was found that newly formed bone tissue continued to increase with the gradual reduction of materials residual in the MWC scaffolds. Furthermore, the immunohistochemical analysis further offered the evidence of the stimulatory effects of MWC scaffolds on osteogenic-related cell differentiation and new bone regeneration. The results indicated that MWC scaffolds with good biocompability and degradability could promote osteogenesis in vivo, which would have potential for bone tissue repair.

Unseen but present danger: improving the safe prescribing of anti-embolism stockings (AES).

PubMed

Bradley, Alison

2014-01-01

A strong evidence base exists supporting thromboprophylaxis for venous thromboembolism (VTE) in surgical patients. Given the ageing population, obesity epidemic, and rise in type 2 diabetes, VTE and peripheral vascular disease (PAD) are likely to become an escalating problem. PAD is a contraindication to the use of anti-embolism stockings (AES). Half of those patients diagnosed with PAD report no symptoms, potentially underestimating its prevalence. Implementation of guidelines for thromboprophylaxis, including the safe prescribing of AES, is therefore imperative. The aims of this project were to establish whether thromboprophylaxis was being prescribed correctly, and appropriately, to all surgical inpatients. This included documented evidence that peripheral pulses had been examined - and, in the case of diabetic patients, that there was documentation of full peripheral neurovascular examination - before AES were prescribed. Data were collected from case notes of all surgical inpatients. Foundation year 1 doctors (FY1s) completed a questionnaire assessing their knowledge of local guidelines. Teaching sessions and posters summarising local guidelines were delivered to FY1s. Appropriate pharmacological prescribing improved from 57.69% to 100%. AES were appropriately prescribed for 65.38% of patients. Post intervention this increased to 79.17%. 0% had documented peripheral neurovascular examination. This increased to 50% post intervention.

A Novel Byte-Substitution Architecture for the AES Cryptosystem.

PubMed

Hossain, Fakir Sharif; Ali, Md Liakot

2015-01-01

The performance of Advanced Encryption Standard (AES) mainly depends on speed, area and power. The S-box represents an important factor that affects the performance of AES on each of these factors. A number of techniques have been presented in the literature, which have attempted to improve the performance of the S-box byte-substitution. This paper proposes a new S-box architecture, defining it as ultra low power, robustly parallel and highly efficient in terms of area. The architecture is discussed for both CMOS and FPGA platforms, and the pipelined architecture of the proposed S-box is presented for further time savings and higher throughput along with higher hardware resources utilization. A performance analysis and comparison of the proposed architecture is also conducted with those achieved by the existing techniques. The results of the comparison verify the outperformance of the proposed architecture in terms of power, delay and size.

Boron detection from blood samples by ICP-AES and ICP-MS during boron neutron capture therapy.

PubMed

Linko, S; Revitzer, H; Zilliacus, R; Kortesniemi, M; Kouri, M; Savolainen, S

2008-01-01

The concept of boron neutron capture therapy (BNCT) involves infusion of a (10)B containing tracer into the patient's bloodstream followed by local neutron irradiation(s). Accurate estimation of the blood boron level for the treatment field before irradiation is required. Boron concentration can be quantified by inductively coupled plasma atomic emission spectrometry (ICP-AES), mass spectrometry (ICP-MS), spectrofluorometric and direct current atomic emission spectrometry (DCP-AES) or by prompt gamma photon detection methods. The blood boron concentrations were analysed and compared using ICP-AES and ICP-MS to ensure congruency of the results if the analysis had to be changed during the treatment, e.g. for technical reasons. The effect of wet-ashing on the results was studied in addition. The mean of all samples analysed with ICP-MS was 5.8 % lower than with ICP-AES coupled to wet-ashing (R (2) = 0.88). Without wet-ashing, the mean of all samples analysed with ICP-MS was 9.1 % higher than with ICP-AES (R (2) = 0.99). Boron concentration analysed from whole blood samples with ICP-AES correlated well with the values of ICP-MS with wet-ashing of the sample matrix, which is generally considered the reference method. When using these methods in parallel at certain intervals during the treatments, reliability of the blood boron concentration values remains satisfactory, taking into account the required accuracy of dose determination in the irradiation of cancer patients.

Validation of the Italian version of the Apathy Evaluation Scale (AES-I) in institutionalized geriatric patients.

PubMed

Borgi, Marta; Caccamo, Floriana; Giuliani, Alessandro; Piergentili, Alessandro; Sessa, Sonia; Reda, Emilia; Alleva, Enrico; Cirulli, Francesca; Miraglia, Fabio

2016-01-01

Apathy is a very common symptom in the institutionalized elderly and represents a condition of both clinical and public health importance. The Apathy Evaluation Scale (AES) has been shown to be a valid and reliable tool for characterizing, quantifying and differentiating apathy in various health conditions. The aims of this study were to establish the validity and reliability of the Italian version of the AES, and to assess the severity of apathy in a sample of Italian institutionalized geriatric patients. Data were collected from clinical interviews using the AES informant version (AES-I). Associations between measures of apathy and depression, cognitive functioning and perceived quality of life were evaluated, as well as the effects of the living environment on apathetic symptoms. Multiple forms of reliability and validity (i.e. test-retest, internal consistency, discriminability of apathy rating from a standard measure of depression) were satisfied. Our results also show that the characteristics of the care setting may affect the severity of apathetic symptoms. The AES-I Italian version is a reliable and valid instrument for measuring apathy in Italian patients, also allowing a direct comparison with data gathered in other countries.

The L7Ae protein binds to two kink-turns in the Pyrococcus furiosus RNase P RNA

PubMed Central

Lai, Stella M.; Lai, Lien B.; Foster, Mark P.; Gopalan, Venkat

2014-01-01

The RNA-binding protein L7Ae, known for its role in translation (as part of ribosomes) and RNA modification (as part of sn/oRNPs), has also been identified as a subunit of archaeal RNase P, a ribonucleoprotein complex that employs an RNA catalyst for the Mg2+-dependent 5′ maturation of tRNAs. To better understand the assembly and catalysis of archaeal RNase P, we used a site-specific hydroxyl radical-mediated footprinting strategy to pinpoint the binding sites of Pyrococcus furiosus (Pfu) L7Ae on its cognate RNase P RNA (RPR). L7Ae derivatives with single-Cys substitutions at residues in the predicted RNA-binding interface (K42C/C71V, R46C/C71V, V95C/C71V) were modified with an iron complex of EDTA-2-aminoethyl 2-pyridyl disulfide. Upon addition of hydrogen peroxide and ascorbate, these L7Ae-tethered nucleases were expected to cleave the RPR at nucleotides proximal to the EDTA-Fe–modified residues. Indeed, footprinting experiments with an enzyme assembled with the Pfu RPR and five protein cofactors (POP5, RPP21, RPP29, RPP30 and L7Ae–EDTA-Fe) revealed specific RNA cleavages, localizing the binding sites of L7Ae to the RPR's catalytic and specificity domains. These results support the presence of two kink-turns, the structural motifs recognized by L7Ae, in distinct functional domains of the RPR and suggest testable mechanisms by which L7Ae contributes to RNase P catalysis. PMID:25361963

Converting neutron stars into strange stars

NASA Technical Reports Server (NTRS)

Olinto, A. V.

1991-01-01

If strange matter is formed in the interior of a neutron star, it will convert the entire neutron star into a strange star. The proposed mechanisms are reviewed for strange matter seeding and the possible strange matter contamination of neutron star progenitors. The conversion process that follows seeding and the recent calculations of the conversion timescale are discussed.

Repression of HNF1α-mediated transcription by amino-terminal enhancer of split (AES)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Eun Hee; Gorman, Amanda A.; Singh, Puja

2015-12-04

HNF1α (Hepatocyte Nuclear Factor 1α) is one of the master regulators in pancreatic beta-cell development and function, and the mutations in Hnf1α are the most common monogenic causes of diabetes mellitus. As a member of the POU transcription factor family, HNF1α exerts its gene regulatory function through various molecular interactions; however, there is a paucity of knowledge in their functional complex formation. In this study, we identified the Groucho protein AES (Amino-terminal Enhancer of Split) as a HNF1α-specific physical binding partner and functional repressor of HNF1α-mediated transcription, which has a direct link to glucose-stimulated insulin secretion in beta-cells that ismore » impaired in the HNF1α mutation-driven diabetes. - Highlights: • We identified AES as a transcriptional repressor for HNF1α in pancreatic beta-cell. • AES's repressive activity was HNF1α-specific and was not observed with HNF1β. • AES interacts with the transactivation domain of HNF1α. • Small molecules can be designed or discovered to disrupt this interaction and improve insulin secretion and glucose homeostasis.« less

RESEARCH AREA -- MUNICIPAL WASTE COMBUSTION (AIR POLLUTION TECHNOLOGY BRANCH, AIR POLLUTION PREVENTION AND CONTROL DIVISION, NRMRL)

EPA Science Inventory

The municipal waste combustion (MWC) program supports the development of revised rules for air pollutant emissions from the MWC source category. Basic research is performed on MWC pollutant formation and control mechanisms for acid gas, trace organic, and trace metal emissions. T...

Assimilation and implications of AE-9/AP-9 in the design process of JPL missions

NASA Astrophysics Data System (ADS)

de Soria-Santacruz Pich, M.; Jun, I.

2015-12-01

The NASA AE-8/AP-8 has been the standard geospace environment specification for decades. This model describes the energetic particle environment around the Earth and is currently the default model used in the design of space missions at the Jet Propulsion Laboratory (JPL). Moreover, the model plays a critical role in the determination of the shielding and survivability of the satellites orbiting our planet. A recent update supported by the Air Force Research Laboratory (AFRL) and the National Reconnaissance Office (NRO), the AE-9/AP-9 model, was released in September 2012 and included many improvements like increased spatial resolution and the specification of the uncertainty due to instrument errors or space weather variability. A current effort at JPL is in place with the objective of making a decision within the Laboratory on the transition from AE-8/AP-8 to the new AE-9/AP-9. In this study we present the results of this effort, which involves the comparison between both versions of the model for different satellite orbits, the comparison between AE-9/AP-9 and in-situ satellite data from the Van Allen Probes and the OSTM/Jason 2 satellite, and the implications of adopting the new model for spacecraft design in terms of survivability, shielding, single event effects, and spacecraft charging.

Structural, elastic, electronic, optical and thermoelectric properties of the Zintl-phase Ae3AlAs3 (Ae = Sr, Ba)

NASA Astrophysics Data System (ADS)

Benahmed, A.; Bouhemadou, A.; Alqarni, B.; Guechi, N.; Al-Douri, Y.; Khenata, R.; Bin-Omran, S.

2018-05-01

First-principles calculations were performed to investigate the structural, elastic, electronic, optical and thermoelectric properties of the Zintl-phase Ae3AlAs3 (Ae = Sr, Ba) using two complementary approaches based on density functional theory. The pseudopotential plane-wave method was used to explore the structural and elastic properties whereas the full-potential linearised augmented plane wave approach was used to study the structural, electronic, optical and thermoelectric properties. The calculated structural parameters are in good consistency with the corresponding measured ones. The single-crystal and polycrystalline elastic constants and related properties were examined in details. The electronic properties, including energy band dispersions, density of states and charge-carrier effective masses, were computed using Tran-Blaha modified Becke-Johnson functional for the exchange-correlation potential. It is found that both studied compounds are direct band gap semiconductors. Frequency-dependence of the linear optical functions were predicted for a wide photon energy range up to 15 eV. Charge carrier concentration and temperature dependences of the basic parameters of the thermoelectric properties were explored using the semi-classical Boltzmann transport model. Our calculations unveil that the studied compounds are characterised by a high thermopower for both carriers, especially the p-type conduction is more favourable.

Combinations of 148 navigation stars and the star tracker

NASA Technical Reports Server (NTRS)

Duncan, R.

1980-01-01

The angular separation of all star combinations for 148 nav star on the onboard software for space transportation system-3 flight and following missions is presented as well as the separation of each pair that satisfies the viewing constraints of using both star trackers simultaneously. Tables show (1) shuttle star catalog 1980 star position in M 1950 coordinates; (2) two star combination of 148 nav stars; and (3) summary of two star-combinations of the star tracker 5 deg filter. These 148 stars present 10,875 combinations. For the star tracker filters of plus or minus 5 deg, there are 875 combinations. Formalhaut (nav star 26) has the best number of combinations, which is 33.

Clinical evaluation and radiographic assessment of bone lysis of the AES total ankle replacement.

PubMed

Besse, Jean-Luc; Brito, Nuno; Lienhart, Christophe

2009-10-01

AES mobile-bearing total ankle replacement is evolved from the Buechel Pappas model. We report medium-term results of a prospective study with AES. All patients who underwent AES TAR for ankle arthritis, by a single surgeon, from 2003 to 2006 were included, excluding neurologic disease, talar osteonecrosis and malalignment more than 20 degrees. All were reviewed at 6 months, 1 year, and at yearly intervals thereafter. X-rays were analyzed by three observers, using a 10-zone protocol. Fifty consecutive AES implants in 47 patients (mean age, 56 years; range, 21 to 79 year) were included, with at least 2 years' followup (mean 40 months). Preoperative diagnosis was mainly post-traumatic (50%) and osteoarthritis secondary to instability (36%). Associated procedures were performed in 38%. Eighty-two percent had good functional results. The mean AOFAS score rose from 36.9 +/- 1.7 preoperatively to 85.4 +/- 12, dorsiflexion from 3 degrees to 7.3 degrees, and plantarflexion from 30.8 degrees to 37.8 degrees. Two ankles underwent secondary arthrodesis for talar subsidence and mechanical dislocation. Ninety-eight percent of implants were well positioned at 90 degrees +/-4. Mean prosthesis ROM on X-ray was 22.1 degrees. There were tibia/implant interface cysts (greater than 5 mm) in 62% of cases, and talar/implant interface cysts in 43%. Although functional outcomes were comparable to the other mobile TAR in the literature, bone lysis with the AES prosthesis was more frequent with risk of subsidence. We therefore stopped implantation of this prosthesis and recommend preventive grafting for severe lysis.

The AES total ankle replacement: A mid-term analysis of 93 cases.

PubMed

Henricson, Anders; Knutson, Kaj; Lindahl, Johan; Rydholm, Urban

2010-06-01

There are few studies concerning specific total ankle arthroplasties. This study reports mid-term survival data for the AES prosthesis. Ninety-three AES ankle arthroplasties were performed by the senior authors. The mean follow-up was 3.5 years. The 5-year survivorship and also the number of simultaneous procedures, reoperations, additional procedures and revisions are analyzed. The 5-year survivorship with revision for any reason as end-point was 90%. Simultaneous procedures were performed in 25 patients, deltoid release and subtalar fusion being the most common. There were seven revisions, one due to loosening, and two due to infection, instability and fractures, respectively. Twenty-seven reoperations or additional procedures were performed in 23 patients with a procedure for malleolar impingement being the most common reoperation, and correction of hindfoot varus being the most common reason for an additional procedure. The AES total ankle replacement seems to be a reasonably safe procedure in experienced hands. Copyright 2009 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

An AES chip with DPA resistance using hardware-based random order execution

NASA Astrophysics Data System (ADS)

Bo, Yu; Xiangyu, Li; Cong, Chen; Yihe, Sun; Liji, Wu; Xiangmin, Zhang

2012-06-01

This paper presents an AES (advanced encryption standard) chip that combats differential power analysis (DPA) side-channel attack through hardware-based random order execution. Both decryption and encryption procedures of an AES are implemented on the chip. A fine-grained dataflow architecture is proposed, which dynamically exploits intrinsic byte-level independence in the algorithm. A novel circuit called an HMF (Hold-Match-Fetch) unit is proposed for random control, which randomly sets execution orders for concurrent operations. The AES chip was manufactured in SMIC 0.18 μm technology. The average energy for encrypting one group of plain texts (128 bits secrete keys) is 19 nJ. The core area is 0.43 mm2. A sophisticated experimental setup was built to test the DPA resistance. Measurement-based experimental results show that one byte of a secret key cannot be disclosed from our chip under random mode after 64000 power traces were used in the DPA attack. Compared with the corresponding fixed order execution, the hardware based random order execution is improved by at least 21 times the DPA resistance.

Infrared observations of AE Aquarii

NASA Technical Reports Server (NTRS)

Tanzi, E. G.; Chincarini, G.; Tarenghi, M.

1981-01-01

Broadband infrared observations of the cataclysmic variable AE Aquarii are reported. The observations were obtained in the J, H, K and L filters with the InSb photometer attached to the 1-m telescope of the European Southern Observatory. The infrared energy distribution observed from 0.35 to 3.5 microns for phase 0.5 suggests a spectral type of K5 V for the secondary and a distance to the system of approximately 70 pc if an absolute magnitude of 7.3 is assumed. Monitoring of the flux at 2.2 microns reveals a variability with an amplitude of approximately 0.3 magnitude over one third of the orbital period, the nature of which is under investigation.

A Novel Byte-Substitution Architecture for the AES Cryptosystem

PubMed Central

Hossain, Fakir Sharif; Ali, Md. Liakot

2015-01-01

The performance of Advanced Encryption Standard (AES) mainly depends on speed, area and power. The S-box represents an important factor that affects the performance of AES on each of these factors. A number of techniques have been presented in the literature, which have attempted to improve the performance of the S-box byte-substitution. This paper proposes a new S-box architecture, defining it as ultra low power, robustly parallel and highly efficient in terms of area. The architecture is discussed for both CMOS and FPGA platforms, and the pipelined architecture of the proposed S-box is presented for further time savings and higher throughput along with higher hardware resources utilization. A performance analysis and comparison of the proposed architecture is also conducted with those achieved by the existing techniques. The results of the comparison verify the outperformance of the proposed architecture in terms of power, delay and size. PMID:26491967

Decryption-decompression of AES protected ZIP files on GPUs

NASA Astrophysics Data System (ADS)

Duong, Tan Nhat; Pham, Phong Hong; Nguyen, Duc Huu; Nguyen, Thuy Thanh; Le, Hung Duc

2011-10-01

AES is a strong encryption system, so decryption-decompression of AES encrypted ZIP files requires very large computing power and techniques of reducing the password space. This makes implementations of techniques on common computing system not practical. In [1], we reduced the original very large password search space to a much smaller one which surely containing the correct password. Based on reduced set of passwords, in this paper, we parallel decryption, decompression and plain text recognition for encrypted ZIP files by using CUDA computing technology on graphics cards GeForce GTX295 of NVIDIA, to find out the correct password. The experimental results have shown that the speed of decrypting, decompressing, recognizing plain text and finding out the original password increases about from 45 to 180 times (depends on the number of GPUs) compared to sequential execution on the Intel Core 2 Quad Q8400 2.66 GHz. These results have demonstrated the potential applicability of GPUs in this cryptanalysis field.

AE monitoring instrumentation for high performance superconducting dipoles and quadrupoles, Phase 2

NASA Astrophysics Data System (ADS)

Iwasa, Y.

1986-01-01

In the past year and a half, attention has been focused on the development of instrumentation for on-line monitoring of high-performance superconducting dipoles and quadrupoles. This instrumentation has been completed and satisfactorily demonstrated on a prototype Fermi dipole. Conductor motion is the principal source of acoustic emission (AE) and the major cause of quenches in the dipole, except during the virgin run when other sources are also present. The motion events are mostly microslips. The middle of the magnet is most susceptible to quenches. This result agrees with the peak field location in the magnet. In the virgin state the top and bottom of the magnet appeared acoustically similar but diverged after training, possibly due to minute structural asymmetry, for example differences in clamping and welding strength; however, the results do not indicate any major structural defects. There is good correlation between quench current and AE starting current. The correlation is reasonable if mechanical disturbances are indeed responsible for quench. Based on AE cumulative history, the average frictional power dissipation in the whole dipole winding is estimated to be approx. 10 (MU)W cm(-3). We expect to implement the following in the next phase of this project: Application of room-temperature techniques to detecting structural defects in the dipole; application of the system to other dipoles and quadrupoles in the same series to compare their performances; and further investigation of AE starting current approx. quench current relationship. Work has begun on the room temperature measurements. Preliminary Stress Wave Factor measurements have been made on a model dipole casing.

Amino-terminal enhancer of split (AES) interacts with the oncoprotein NUP98-HOXA9 and enhances its transforming ability.

PubMed

Sarma, Nayan J; Yaseen, Nabeel R

2011-11-11

NUP98-HOXA9 is the prototype of NUP98 fusion oncoproteins that cause acute myeloid leukemia. It consists of an N-terminal FG-rich portion of the nucleoporin NUP98 fused to the homeodomain region of the homeobox protein HOXA9, and acts as an aberrant transcription factor. To identify interacting partners of NUP98-HOXA9, we used a cytoplasmic yeast two-hybrid assay to avoid the nonspecific trans-activation that would occur with the traditional yeast two-hybrid assay due to the transactivating properties of NUP98-HOXA9. We identified amino-terminal enhancer of split (AES), a transcriptional regulator of the transducin-like enhancer/Groucho family as a novel interaction partner of NUP98-HOXA9. The interaction was confirmed by in vitro pulldown and co-immunoprecipitation assays and was shown to require the FG repeat region of NUP98-HOXA9. Immunofluorescence analysis showed that AES localizes primarily to the interior of the nucleus. AES also showed a strong interaction with wild-type NUP98. AES augmented the transcriptional activity of NUP98-HOXA9. In the presence of NUP98-HOXA9, AES caused an increase in long-term proliferation of primary human CD34+ cells with a marked increase in the numbers of primitive cells. These effects of AES were not observed in the absence of NUP98-HOXA9. AES knockdown diminished the transcriptional and proliferative effects of NUP98-HOXA9. AES caused a shift away from the erythroid lineage in cells expressing NUP98-HOXA9. These data establish AES as an interacting partner of NUP98-HOXA9 and show that it cooperates with NUP98-HOXA9 in transcriptional regulation and cell transformation.

Amino-terminal Enhancer of Split (AES) Interacts with the Oncoprotein NUP98-HOXA9 and Enhances Its Transforming Ability*

PubMed Central

Sarma, Nayan J.; Yaseen, Nabeel R.

2011-01-01

NUP98-HOXA9 is the prototype of NUP98 fusion oncoproteins that cause acute myeloid leukemia. It consists of an N-terminal FG-rich portion of the nucleoporin NUP98 fused to the homeodomain region of the homeobox protein HOXA9, and acts as an aberrant transcription factor. To identify interacting partners of NUP98-HOXA9, we used a cytoplasmic yeast two-hybrid assay to avoid the nonspecific trans-activation that would occur with the traditional yeast two-hybrid assay due to the transactivating properties of NUP98-HOXA9. We identified amino-terminal enhancer of split (AES), a transcriptional regulator of the transducin-like enhancer/Groucho family as a novel interaction partner of NUP98-HOXA9. The interaction was confirmed by in vitro pulldown and co-immunoprecipitation assays and was shown to require the FG repeat region of NUP98-HOXA9. Immunofluorescence analysis showed that AES localizes primarily to the interior of the nucleus. AES also showed a strong interaction with wild-type NUP98. AES augmented the transcriptional activity of NUP98-HOXA9. In the presence of NUP98-HOXA9, AES caused an increase in long-term proliferation of primary human CD34+ cells with a marked increase in the numbers of primitive cells. These effects of AES were not observed in the absence of NUP98-HOXA9. AES knockdown diminished the transcriptional and proliferative effects of NUP98-HOXA9. AES caused a shift away from the erythroid lineage in cells expressing NUP98-HOXA9. These data establish AES as an interacting partner of NUP98-HOXA9 and show that it cooperates with NUP98-HOXA9 in transcriptional regulation and cell transformation. PMID:21937451

O stars and Wolf-Rayet stars

NASA Technical Reports Server (NTRS)

Conti, Peter S.; Underhill, Anne B.; Jordan, Stuart (Editor); Thomas, Richard (Editor)

1988-01-01

Basic information is given about O and Wolf-Rayet stars indicating how these stars are defined and what their chief observable properties are. Part 2 of the volume discussed four related themes pertaining to the hottest and most luminous stars. Presented are: an observational overview of the spectroscopic classification and extrinsic properties of O and Wolf-Rayet stars; the intrinsic parameters of luminosity, effective temperature, mass, and composition of the stars, and a discussion of their viability; stellar wind properties; and the related issues concerning the efforts of stellar radiation and wind on the immediate interstellar environment are presented.

Stars

NASA Astrophysics Data System (ADS)

Capelato, Hugo Vicente

1999-01-01

We will begin our study with a more or less superficial inspection of the "forest" of stars that we see in the skies. The first thing we notice is that, as sources of light, they are much weaker than the Sun. Second, their apparent colors vary; from a bluish-white in most of them to a reddish-yellow, which is rarer. There is also a third aspect, though it is not very obvious to the naked eye: most of the stars group themselves in small families of two, three or more members. A good example is the Alpha Centauri, the closest star to us, which, in fact, is a triple system of stars. Another is the group of 7 stars that make up the Pleiades, which will be discussed later on. In fact, almost half of the stars are double systems with only two members, called binary stars. Most of these double stars, though together, are separated by several astronomical units (one astronomical unit, AU, is the distance from Earth to the sun: see Chapter 1), and revolve around each other over periods of several years. And yet the revolutions of some binary stars, separated by much smaller distances, occur in only a few hours! These stars are so close to each other that they can share enveloping material. Often this exchange occurs in a somewhat violent manner. Local explosions may occur, expelling matter away from the system. In other binary systems, where one of the components is a very compact, dense star, companion material flows more calmly, making up a light disk around the compact star.

77 FR 71189 - AES Beaver Valley, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-29

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-442-000] AES Beaver Valley, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding, of AES Beaver...

75 FR 70742 - AES Laurel Mountain, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-18

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-2036-000] AES Laurel Mountain, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket... proceeding of AES Laurel Mountain, LLC's application for market-based rate authority, with an accompanying...

A study of the initial oxidation of evaporated thin films of aluminum by AES, ELS, and ESD

NASA Technical Reports Server (NTRS)

Bujor, M.; Larson, L. A.; Poppa, H.

1982-01-01

The room temperature, low pressure, oxidation of evaporated aluminum thin films has been studied by AES, ELS, and ESD. ESD was the most sensitive of the three methods to characterize a clean aluminum surface. Two oxidation stages were distinguished in the 0-3000 L oxygen exposure range. Between 0 and 50 L, the chemisorption of oxygen atoms was characterized by a fast decrease of the 67 eV AES Al peak and the 10 eV surface plasmon peak, and by a simultaneous increase of the oxygen AES and ESD signals. After 50 L, a change in slope in all AES and ESD signal variations was attributed to the slow growth of a thin layer of aluminum oxide, which after 3000 L was still only a few angstroms thick.

The effector gene xopAE of Xanthomonas euvesicatoria 85-10 is part of an operon and encodes an E3 ubiquitin ligase.

PubMed

Popov, Georgy; Majhi, Bharat Bhusan; Sessa, Guido

2018-05-21

The type III effector XopAE from the Xanthomonas euvesicatoria strain 85-10 ( Xe 85-10) was previously shown to inhibit plant immunity and enhance pathogen-induced disease symptoms. Evolutionary analysis of 60 xopAE alleles ( AEal ) revealed that the xopAE locus is conserved in multiple Xanthomonas species. The majority of xopAE alleles (55 out of 60) encodes a single ORF ( xopAE ), while in 5 alleles, including AEal 37 of the Xe 85-10 strain, a frame-shift splits the locus into two ORFs ( hpaF and a truncated xopAE ). To test whether the second ORF of AEal 37 ( xopAE 85-10 ) is translated, we examined expression of YFP fused downstream to truncated or mutant forms of the locus in Xanthomonas bacteria. YFP fluorescence was detected at maximal levels when the reporter was in proximity of an internal ribosome-binding site upstream to a rare ATT start codon in the xopAE 85-10 ORF, but severely reduced when these elements were abolished. In agreement with the notion that xopAE 85- 10 is a functional gene, its protein product was translocated into plant cells by the type III secretion system and translocation was dependent on its upstream ORF hpaF. Homology modeling predicted that XopAE 85-10 contains an E3 ligase XL-box domain at the C-terminus, and in vitro assays demonstrated that this domain displays mono-ubiquitination activity. Remarkably, the XL-box was essential for XopAE 85-10 to inhibit PAMP-induced gene expression in Arabidopsis protoplasts. Together, these results indicate that the xopAE 85-10 gene resides in a functional operon, which utilizes the alternative start codon ATT, and encodes a novel XL-box E3 ligase. Importance Xanthomonas bacteria utilize a type III secretion system to cause disease in many crops. This study provides insights into evolution, translocation and biochemical function of the XopAE type III secreted effector contributing to the understanding of Xanthomonas-host interactions. We establish XopAE as core effector of seven Xanthomonas

A robust star identification algorithm with star shortlisting

NASA Astrophysics Data System (ADS)

Mehta, Deval Samirbhai; Chen, Shoushun; Low, Kay Soon

2018-05-01

A star tracker provides the most accurate attitude solution in terms of arc seconds compared to the other existing attitude sensors. When no prior attitude information is available, it operates in "Lost-In-Space (LIS)" mode. Star pattern recognition, also known as star identification algorithm, forms the most crucial part of a star tracker in the LIS mode. Recognition reliability and speed are the two most important parameters of a star pattern recognition technique. In this paper, a novel star identification algorithm with star ID shortlisting is proposed. Firstly, the star IDs are shortlisted based on worst-case patch mismatch, and later stars are identified in the image by an initial match confirmed with a running sequential angular match technique. The proposed idea is tested on 16,200 simulated star images having magnitude uncertainty, noise stars, positional deviation, and varying size of the field of view. The proposed idea is also benchmarked with the state-of-the-art star pattern recognition techniques. Finally, the real-time performance of the proposed technique is tested on the 3104 real star images captured by a star tracker SST-20S currently mounted on a satellite. The proposed technique can achieve an identification accuracy of 98% and takes only 8.2 ms for identification on real images. Simulation and real-time results depict that the proposed technique is highly robust and achieves a high speed of identification suitable for actual space applications.

Rutting and fatigue properties of plant mixes from AE stone.

DOT National Transportation Integrated Search

2006-06-01

Loose mix from A.E. Stone, Inc. in Egg Harbor Township, NJ was supplied to the : Rutgers Asphalt Pavement Laboratory (RAPL) for evaluation. Three different plant : mixes were supplied for permanent deformation (rutting) and flexural fatigue testing; ...

Winter Refuge for Aedes aegypti and Ae. albopictus Mosquitoes in Hanoi during Winter

PubMed Central

Tsunoda, Takashi; Cuong, Tran Chi; Dong, Tran Duc; Yen, Nguyen Thi; Le, Nguyen Hoang; Phong, Tran Vu; Minakawa, Noboru

2014-01-01

Dengue occurs throughout the year in Hanoi, Vietnam, despite winter low temperatures <10°C. During July 2010 to March 2012, we surveyed monthly for Aedes larvae and pupae in 120 houses in 8 Hanoi districts. Aedes albopictus preferred discarded containers in summer and pupal density drastically decreased in winter. Aedes aegypti preferred concrete tanks and this preference increased in winter. Even in winter, the lowest water temperature found in concrete tanks was >14°C, exceeding the developmental zero point of Ae. aegypti. Although jars, drums and concrete tanks were the dominant containers previously (1994–97) in Hanoi, currently the percentage of residences with concrete tanks was still high while jars and drums were quite low. Our study showed that concrete tanks with broken lids allowing mosquitoes access were important winter refuge for Ae. aegypti. We also indicate a concern about concrete tanks serving as foci for Ae. aegypti to expand their distribution in cooler regions. PMID:24752230

Adaptor protein 1 B mu subunit does not contribute to the recycling of kAE1 protein in polarized renal epithelial cells.

PubMed

Almomani, Ensaf Y; Touret, Nicolas; Cordat, Emmanuelle

2018-04-13

Mutations in the gene encoding the kidney anion exchanger 1 (kAE1) can lead to distal renal tubular acidosis (dRTA). dRTA mutations reported within the carboxyl (C)-terminal tail of kAE1 result in apical mis-targeting of the exchanger in polarized renal epithelial cells. As kAE1 physically interacts with the μ subunit of epithelial adaptor protein 1 B (AP-1B), we investigated the role of heterologously expressed μ1B subunit of the AP-1B complex for kAE1 retention to the basolateral membrane in polarized porcine LLC-PK1 renal epithelial cells that are devoid of endogenous AP-1B. We confirmed the interaction and close proximity between kAE1 and μ1B using immunoprecipitation and proximity ligation assay, respectively. Expressing the human μ1B subunit in these cells decreased significantly the amount of cell surface kAE1 at the steady state, but had no significant effect on kAE1 recycling and endocytosis. We show that (i) heterologous expression of μ1B displaces the physical interaction of endogenous GAPDH with kAE1 WT supporting that both AP-1B and GAPDH proteins bind to an overlapping site on kAE1 and (ii) phosphorylation of tyrosine 904 within the potential YDEV interaction motif does not alter the kAE1/AP-1B interaction. We conclude that μ1B subunit is not involved in recycling of kAE1.

Cull sow knife-separable lean content evaluation at harvest and lean mass content prediction equation development.

PubMed

Abell, Caitlyn E; Stalder, Kenneth J; Hendricks, Haven B; Fitzgerald, Robert F

2012-07-01

The objectives of this study were to develop a prediction equation for carcass knife-separable lean within and across USDA cull sow market weight classes (MWC) and to determine carcass and individual primal cut knife separable lean content from cull sows. There were significant percent lean and fat differences in the primal cuts across USDA MWC. The two lighter USDA MWC had a greater percent carcass lean and lower percent fat compared to the two heavier MWC. In general, hot carcass weight explained the majority of carcass lean variation. Additionally, backfat was a significant variation source when predicting cull sow carcass lean. The findings support using a single lean prediction equation across MWC to assist processors when making cull sow purchasing decisions and determine the mix of animals from various USDA MWC that will meet their needs when making pork products with defined lean:fat content. Copyright © 2012 Elsevier Ltd. All rights reserved.

Systematic search for high-energy gamma-ray emission from bow shocks of runaway stars

DOE PAGES

Schulz, A.; Ackermann, M.; Buehler, R.; ...

2014-05-01

Context. It has been suggested that the bow shocks of runaway stars are sources of high-energy gamma rays (E > 100 MeV). Theoretical models predicting high-energy gamma-ray emission from these sources were followed by the first detection of non-thermal radio emission from the bow shock of BD+43°3654 and non-thermal X-ray emission from the bow shock of AE Aurigae. Aims. We perform the first systematic search for MeV and GeV emission from 27 bow shocks of runaway stars using data collected by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope (Fermi). Methods. We analysed 57 months of Fermi-LATmore » data at the positions of 27 bow shocks of runaway stars extracted from the Extensive stellar BOw Shock Survey catalogue (E-BOSS). A likelihood analysis was performed to search for gamma-ray emission that is not compatible with diffuse background or emission from neighbouring sources and that could be associated with the bow shocks. Results. None of the bow shock candidates is detected significantly in the Fermi-LAT energy range. We therefore present upper limits on the high-energy emission in the energy range from 100MeV to 300 GeV for 27 bow shocks of runaway stars in four energy bands. For the three cases where models of the high-energy emission are published we compare our upper limits to the modelled spectra. Our limits exclude the model predictions for ζ Ophiuchi by a factor ≈ 5.« less

19 CFR 192.13 - Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures.

Code of Federal Regulations, 2010 CFR

2010-04-01

... (Option 4) filing privileges; appeal procedures. 192.13 Section 192.13 Customs Duties U.S. CUSTOMS AND... Filing of Export Information Through the Automated Export System (AES) § 192.13 Revocation of participants' AES post-departure (Option 4) filing privileges; appeal procedures. (a) Reasons for revocation...

BOREAS AES MARSII Surface Meteorological Data

NASA Technical Reports Server (NTRS)

Atkinson, G. Barrie; Funk, Barry; Hall, Forrest G. (Editor); Knapp, David E. (Editor)

2000-01-01

Canadian AES personnel collected several data sets related to surface and atmospheric meteorological conditions over the BOREAS region. This data set contains 15-minute meteorological data from six MARSII meteorology stations in the BOREAS region in Canada. Parameters include site, time, temperature, dewpoint, visibility, wind speed, wind gust, wind direction, two cloud groups, precipitation, and station pressure. Temporally, the data cover the period of May to September 1994. Geo-graphically, the stations are spread across the provinces of Saskatchewan and Manitoba. The data are provided in tabular ASCII files, and are classified as AFM-Staff data.

BOREAS AES READAC Surface Meteorological Data

NASA Technical Reports Server (NTRS)

Atkinson, G. Barrie; Funk, Barry; Hall, Forrest G. (Editor); Knapp, David E. (Editor)

2000-01-01

Canadian AES personnel collected and processed data related to surface atmospheric meteorological conditions over the BOREAS region. This data set contains 15-minute meteorological data from one READAC meteorology station in Hudson Bay, Saskatchewan. Parameters include day, time, type of report, sky condition, visibility, mean sea level pressure, temperature, dewpoint, wind, altimeter, opacity, minimum and maximum visibility, station pressure, minimum and maximum air temperature, a wind group, precipitation, and precipitation in the last hour. The data were collected non-continuously from 24-May-1994 to 20-Sep-1994. The data are provided in tabular ASCII files, and are classified as AFM-Staff data.

On the origin of the peculiar cataclysmic variable AE Aquarii

NASA Astrophysics Data System (ADS)

Beskrovnaya, N. G.; Ikhsanov, N. R.

2015-02-01

The nova-like variable AE Aquarii is a close binary system containing a red dwarf and a magnetized white dwarf rotating with the period of 33 s. A short spin period of the white dwarf is caused by an intensive mass exchange between the system components during a previous epoch. We show that a high rate of disk accretion onto the white dwarf surface resulted in temporary screening of its magnetic field and spin-up of the white dwarf to its present spin period. Transition of the white dwarf to the ejector state occurred at a final stage of the spin-up epoch after its magnetic field had emerged from the accreted plasma due to diffusion. In the frame of this scenario AE Aqr represents a missing link in the chain of Polars evolution and the white dwarf resembles a recycled pulsar.

Insecticide susceptibility of Aedes albopictus and Ae. aegypti from Brazil and the Swiss-Italian border region.

PubMed

Suter, Tobias; Crespo, Mônica Maria; de Oliveira, Mariana Francelino; de Oliveira, Thaynan Sama Alves; de Melo-Santos, Maria Alice Varjal; de Oliveira, Cláudia Maria Fontes; Ayres, Constância Flávia Junqueira; Barbosa, Rosângela Maria Rodrigues; Araújo, Ana Paula; Regis, Lêda Narcisa; Flacio, Eleonora; Engeler, Lukas; Müller, Pie; Silva-Filha, Maria Helena Neves Lobo

2017-09-19

Aedes aegypti and Ae. albopictus are two highly invasive mosquito species, both vectors of several viruses, including dengue, chikungunya and Zika. While Ae. aegypti is the primary vector in the tropics and sub-tropics, Ae. albopictus is increasingly under the public health watch as it has been implicated in arbovirus-transmission in more temperate regions, including continental Europe. Vector control using insecticides is the pillar of most control programmes; hence development of insecticide resistance is of great concern. As part of a Brazilian-Swiss Joint Research Programme we set out to assess whether there are any signs of existing or incipient insecticide resistance primarily against the larvicide Bacillus thuringiensis svar. israelensis (Bti), but also against currently applied and potentially alternative insecticides in our areas, Recife (Brazil) and the Swiss-Italian border region. Following World Health Organization guidelines, dose-response curves for a range of insecticides were established for both colonized and field caught Ae. aegypti and Ae. albopictus. The larvicides included Bti, two of its toxins, Cry11Aa and Cry4Ba, Lysinibacillus sphaericus, Vectomax CG®, a formulated combination of Bti and L. sphaericus, and diflubenzuron. In addition to the larvicides, the Swiss-Italian Ae. albopictus populations were also tested against five adulticides (bendiocarb, dichlorodiphenyltrichloroethane, malathion, permethrin and λ-cyhalothrin). Showing a similar dose-response, all mosquito populations were fully susceptible to the larvicides tested and, in particular, to Bti which is currently used both in Brazil and Switzerland. In addition, there were no signs of incipient resistance against Bti as larvae were equally susceptible to the individual toxins, Cry11Aa and Cry4Ba. The field-caught Swiss-Italian populations were susceptible to the adulticides tested but DDT mortality rates showed signs of reduced susceptibility. The insecticides currently used for

Role of Cl- -HCO3- exchanger AE3 in intracellular pH homeostasis in cultured murine hippocampal neurons, and in crosstalk to adjacent astrocytes.

PubMed

Salameh, Ahlam I; Hübner, Christian A; Boron, Walter F

2017-01-01

A polymorphism of human AE3 is associated with idiopathic generalized epilepsy. Knockout of AE3 in mice lowers the threshold for triggering epileptic seizures. The explanations for these effects are elusive. Comparisons of cells from wild-type vs. AE3 -/- mice show that AE3 (present in hippocampal neurons, not astrocytes; mediates HCO 3 - efflux) enhances intracellular pH (pH i ) recovery (decrease) from alkali loads in neurons and, surprisingly, adjacent astrocytes. During metabolic acidosis (MAc), AE3 speeds initial acidification, but limits the extent of pH i decrease in neurons and astrocytes. AE3 speeds re-alkalization after removal of MAc in neurons and astrocytes, and speeds neuronal pH i recovery from an ammonium prepulse-induced acid load. We propose that neuronal AE3 indirectly increases acid extrusion in (a) neurons via Cl - loading, and (b) astrocytes by somehow enhancing NBCe1 (major acid extruder). The latter would enhance depolarization-induced alkalinization of astrocytes, and extracellular acidification, and thereby reduce susceptibility to epileptic seizures. The anion exchanger AE3, expressed in hippocampal (HC) neurons but not astrocytes, contributes to intracellular pH (pH i ) regulation by facilitating the exchange of extracellular Cl - for intracellular HCO 3 - . The human AE3 polymorphism A867D is associated with idiopathic generalized epilepsy. Moreover, AE3 knockout (AE3 -/- ) mice are more susceptible to epileptic seizure. The mechanism of these effects has been unclear because the starting pH i in AE3 -/- and wild-type neurons is indistinguishable. The purpose of the present study was to use AE3 -/- mice to investigate the role of AE3 in pH i homeostasis in HC neurons, co-cultured with astrocytes. We find that the presence of AE3 increases the acidification rate constant during pH i recovery from intracellular alkaline loads imposed by reducing [CO 2 ]. The presence of AE3 also speeds intracellular acidification during the early phase of

An Optimal Image-Based Method for Identification of Acoustic Emission (AE) Sources in Plate-Like Structures Using a Lead Zirconium Titanate (PZT) Sensor Array.

PubMed

Yan, Gang; Zhou, Li

2018-02-21

This paper proposes an innovative method for identifying the locations of multiple simultaneous acoustic emission (AE) events in plate-like structures from the view of image processing. By using a linear lead zirconium titanate (PZT) sensor array to record the AE wave signals, a reverse-time frequency-wavenumber (f-k) migration is employed to produce images displaying the locations of AE sources by back-propagating the AE waves. Lamb wave theory is included in the f-k migration to consider the dispersive property of the AE waves. Since the exact occurrence time of the AE events is usually unknown when recording the AE wave signals, a heuristic artificial bee colony (ABC) algorithm combined with an optimal criterion using minimum Shannon entropy is used to find the image with the identified AE source locations and occurrence time that mostly approximate the actual ones. Experimental studies on an aluminum plate with AE events simulated by PZT actuators are performed to validate the applicability and effectiveness of the proposed optimal image-based AE source identification method.

An Optimal Image-Based Method for Identification of Acoustic Emission (AE) Sources in Plate-Like Structures Using a Lead Zirconium Titanate (PZT) Sensor Array

PubMed Central

Zhou, Li

2018-01-01

This paper proposes an innovative method for identifying the locations of multiple simultaneous acoustic emission (AE) events in plate-like structures from the view of image processing. By using a linear lead zirconium titanate (PZT) sensor array to record the AE wave signals, a reverse-time frequency-wavenumber (f-k) migration is employed to produce images displaying the locations of AE sources by back-propagating the AE waves. Lamb wave theory is included in the f-k migration to consider the dispersive property of the AE waves. Since the exact occurrence time of the AE events is usually unknown when recording the AE wave signals, a heuristic artificial bee colony (ABC) algorithm combined with an optimal criterion using minimum Shannon entropy is used to find the image with the identified AE source locations and occurrence time that mostly approximate the actual ones. Experimental studies on an aluminum plate with AE events simulated by PZT actuators are performed to validate the applicability and effectiveness of the proposed optimal image-based AE source identification method. PMID:29466310

Drug-resistant molecular mechanism of CRF01_AE HIV-1 protease due to V82F mutation

NASA Astrophysics Data System (ADS)

Liu, Xiaoqing; Xiu, Zhilong; Hao, Ce

2009-05-01

Human immunodeficiency virus type 1 protease (HIV-1 PR) is one of the major targets of anti-AIDS drug discovery. The circulating recombinant form 01 A/E (CRF01_AE, abbreviated AE) subtype is one of the most common HIV-1 subtypes, which is infecting more humans and is expanding rapidly throughout the world. It is, therefore, necessary to develop inhibitors against subtype AE HIV-1 PR. In this work, we have performed computer simulation of subtype AE HIV-1 PR with the drugs lopinavir (LPV) and nelfinavir (NFV), and examined the mechanism of resistance of the V82F mutation of this protease against LPV both structurally and energetically. The V82F mutation at the active site results in a conformational change of 79's loop region and displacement of LPV from its proper binding site, and these changes lead to rotation of the side-chains of residues D25 and I50'. Consequently, the conformation of the binding cavity is deformed asymmetrically and some interactions between PR and LPV are destroyed. Additionally, by comparing the interactive mechanisms of LPV and NFV with HIV-1 PR we discovered that the presence of a dodecahydroisoquinoline ring at the P1' subsite, a [2-(2,6-dimethylphenoxy)acetyl]amino group at the P2' subsite, and an N2 atom at the P2 subsite could improve the binding affinity of the drug with AE HIV-1 PR. These findings are helpful for promising drug design.

Ammonia Excretion in an Osmoregulatory Syncytium Is Facilitated by AeAmt2, a Novel Ammonia Transporter in Aedes aegypti Larvae

PubMed Central

Durant, Andrea C.; Donini, Andrew

2018-01-01

The larvae of the mosquito Aedes aegypti inhabit ammonia rich septic tanks in tropical regions of the world that make extensive use of these systems, explaining the prevalence of disease during dry seasons. Since ammonia (NH3/NH4+) is toxic to animals, an understanding of the physiological mechanisms of ammonia excretion permitting the survival of A. aegypti larvae in high ammonia environments is important. We have characterized a novel ammonia transporter, AeAmt2, belonging to the Amt/MEP/Rh family of ammonia transporters. Based on the amino acid sequence, the predicted topology of AeAmt2 consists of 11 transmembrane helices with an extracellular N-terminus and a cytoplasmic C-terminus region. Alignment of the predicted AeAmt2 amino acid sequence with other Amt/MEP proteins from plants, bacteria, and yeast highlights the presence of conserved residues characteristic of ammonia conducting channels in this protein. AeAmt2 is expressed in the ionoregulatory anal papillae of A. aegypti larvae where it is localized to the apical membrane of the epithelium. dsRNA-mediated knockdown of AeAmt2 results in a significant decrease in NH4+ efflux from the anal papillae, suggesting a key role in facilitating ammonia excretion. The effect of high environmental ammonia (HEA) on expression of AeAmt2, along with previously characterized AeAmt1, AeRh50-1, and AeRh50-2 in the anal papillae was investigated. We show that changes in expression of ammonia transporters occur in response to acute and chronic exposure to HEA, which reflects the importance of these transporters in the physiology of life in high ammonia habitats. PMID:29695971

Low Cost Design of an Advanced Encryption Standard (AES) Processor Using a New Common-Subexpression-Elimination Algorithm

NASA Astrophysics Data System (ADS)

Chen, Ming-Chih; Hsiao, Shen-Fu

In this paper, we propose an area-efficient design of Advanced Encryption Standard (AES) processor by applying a new common-expression-elimination (CSE) method to the sub-functions of various transformations required in AES. The proposed method reduces the area cost of realizing the sub-functions by extracting the common factors in the bit-level XOR/AND-based sum-of-product expressions of these sub-functions using a new CSE algorithm. Cell-based implementation results show that the AES processor with our proposed CSE method has significant area improvement compared with previous designs.

Massive Stars

NASA Astrophysics Data System (ADS)

Livio, Mario; Villaver, Eva

2009-11-01

Participants; Preface Mario Livio and Eva Villaver; 1. High-mass star formation by gravitational collapse of massive cores M. R. Krumholz; 2. Observations of massive star formation N. A. Patel; 3. Massive star formation in the Galactic center D. F. Figer; 4. An X-ray tour of massive star-forming regions with Chandra L. K. Townsley; 5. Massive stars: feedback effects in the local universe M. S. Oey and C. J. Clarke; 6. The initial mass function in clusters B. G. Elmegreen; 7. Massive stars and star clusters in the Antennae galaxies B. C. Whitmore; 8. On the binarity of Eta Carinae T. R. Gull; 9. Parameters and winds of hot massive stars R. P. Kudritzki and M. A. Urbaneja; 10. Unraveling the Galaxy to find the first stars J. Tumlinson; 11. Optically observable zero-age main-sequence O stars N. R. Walborn; 12. Metallicity-dependent Wolf-Raynet winds P. A. Crowther; 13. Eruptive mass loss in very massive stars and Population III stars N. Smith; 14. From progenitor to afterlife R. A. Chevalier; 15. Pair-production supernovae: theory and observation E. Scannapieco; 16. Cosmic infrared background and Population III: an overview A. Kashlinsky.

Performance evaluation of the Fiber Bragg Grating (FBG) sensing device and comparison with piezoelectric sensors for AE detection

NASA Astrophysics Data System (ADS)

Zhang, Chuang; Bond, Leonard J.

2017-02-01

Structural health monitoring (SHM) of engineering structures in service has assumed a significant role in assessing their safety and integrity. Several sensing modalities have been developed to monitor cracking, using acoustic emission (AE). Piezoelectric sensors are commonly used in AE systems, however, for some applications there are limitations and challenges. One alternative approach that is being investigated is using Fiber Bragg Grating (FBG) sensors which have emerged as a reliable, in situ and nondestructive tool in some applications for monitoring and diagnostics in large-scale structure. The main objective of this work is to evaluate and compare the AE sensing characteristics for FBG and piezoelectric sensors. A ball drop impact is used as the source for generating waves in an Aluminum plate. The source repeatability was verified and a 4-channel FBG AE detection device was used to compare with the response of PZT sensors, investigating amplitude and frequency response which can indicate sensitivity. The low sensitivity and slow sampling rate are identified, for the unit investigated, as the main factors limiting FBG engineering AE applications.

Strange stars

NASA Technical Reports Server (NTRS)

Alcock, Charles; Farhi, Edward; Olinto, Angela

1986-01-01

Strange matter, a form of quark matter that is postulated to be absolute stable, may be the true ground stage of the hadrons. If this hypothesis is correct, neutron stars may convert to 'strange stars'. The mass-radius relation for strange stars is very different from that of neutron stars; there is no minimum mass, and for mass of 1 solar mass or less, mass is proportional to the cube of the radius. For masses between 1 solar mass and 2 solar masses, the radii of strange stars are about 10 km, as for neutron stars. Strange stars may have an exposed quark surface, which is capable of radiating at rates greatly exceeding the Eddington limit, but has a low emissivity for X-ray photons. The stars may have a thin crust with the same composition as the preneutron drip outer layer of a conventional neutron star crust. Strange stars cool efficiently via neutrino emission.

Houttuynoids A-E, anti-herpes simplex virus active flavonoids with novel skeletons from Houttuynia cordata.

PubMed

Chen, Shao-Dan; Gao, Hao; Zhu, Qin-Chang; Wang, Ya-Qi; Li, Ting; Mu, Zhen-Qiang; Wu, Hong-Ling; Peng, Tao; Yao, Xin-Sheng

2012-04-06

Houttuynoids A-E (1-5), a new type of flavonoid with houttuynin tethered to hyperoside, and their presumed biosynthetic precursor hyperoside (6) were isolated from the whole plant of Houttuynia cordata. Their structures were elucidated by analysis of 1D and 2D NMR. A hypothetical biogenetic pathway for houttuynoids A-E was proposed. Compounds 1-5 exhibited potent anti-HSV (herpes simplex viruses) activity.

A PROP1-binding factor, AES cloned by yeast two-hybrid assay represses PROP1-induced Pit-1 gene expression.

PubMed

Sugiyama, Yuka; Ikeshita, Nobuko; Shibahara, Hiromi; Yamamoto, Daisuke; Kawagishi, Mayuko; Iguchi, Genzo; Iida, Keiji; Takahashi, Yutaka; Kaji, Hidesuke; Chihara, Kazuo; Okimura, Yasuhiko

2013-08-25

PROP1 mutation causes combined pituitary hormone deficiency (CPHD). Several mutations are located in a transactivation domain (TAD) of Prop1, and the loss of TAD binding to cofactors is likely the cause of CPHD. PROP1 cofactors have not yet been identified. In the present study, we aimed to identify the PROP1-interacting proteins from the human brain cDNA library. Using a yeast two-hybrid assay, we cloned nine candidate proteins that may bind to PROP1. Of those nine candidates, amino-terminal enhancer of split (AES) was the most abundant, and we analyzed the AES function. AES dose-dependently decreased the PROP1-induced Pit-1 reporter gene expression. An immunoprecipitation assay revealed the relationship between AES and PROP1. In a mammalian two-hybrid assay, a leucine zipper-like motif of the AES Q domain was identified as a region that interacted with TAD. These results indicated that AES was a corepressor of PROP1. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

aes, the gene encoding the esterase B in Escherichia coli, is a powerful phylogenetic marker of the species.

PubMed

Lescat, Mathilde; Hoede, Claire; Clermont, Olivier; Garry, Louis; Darlu, Pierre; Tuffery, Pierre; Denamur, Erick; Picard, Bertrand

2009-12-29

Previous studies have established a correlation between electrophoretic polymorphism of esterase B, and virulence and phylogeny of Escherichia coli. Strains belonging to the phylogenetic group B2 are more frequently implicated in extraintestinal infections and include esterase B2 variants, whereas phylogenetic groups A, B1 and D contain less virulent strains and include esterase B1 variants. We investigated esterase B as a marker of phylogeny and/or virulence, in a thorough analysis of the esterase B-encoding gene. We identified the gene encoding esterase B as the acetyl-esterase gene (aes) using gene disruption. The analysis of aes nucleotide sequences in a panel of 78 reference strains, including the E. coli reference (ECOR) strains, demonstrated that the gene is under purifying selection. The phylogenetic tree reconstructed from aes sequences showed a strong correlation with the species phylogenetic history, based on multi-locus sequence typing using six housekeeping genes. The unambiguous distinction between variants B1 and B2 by electrophoresis was consistent with Aes amino-acid sequence analysis and protein modelling, which showed that substituted amino acids in the two esterase B variants occurred mostly at different sites on the protein surface. Studies in an experimental mouse model of septicaemia using mutant strains did not reveal a direct link between aes and extraintestinal virulence. Moreover, we did not find any genes in the chromosomal region of aes to be associated with virulence. Our findings suggest that aes does not play a direct role in the virulence of E. coli extraintestinal infection. However, this gene acts as a powerful marker of phylogeny, illustrating the extensive divergence of B2 phylogenetic group strains from the rest of the species.

Inner disk clearing around the Herbig Ae star HD 139614: Evidence for a planet-induced gap?

NASA Astrophysics Data System (ADS)

Matter, A.; Labadie, L.; Augereau, J. C.; Kluska, J.; Crida, A.; Carmona, A.; Gonzalez, J. F.; Thi, W. F.; Le Bouquin, J.-B.; Olofsson, J.; Lopez, B.

2016-02-01

Spatially resolving the inner dust cavity (or gap) of the so-called (pre-)transitional disks is a key to understanding the connection between the processes of planetary formation and disk dispersal. The disk around the Herbig star HD 139614 is of particular interest since it presents a pretransitional nature with an au-sized gap structure that is spatially resolved by mid-infrared interferometry in the dust distribution. With the aid of new near-infrared interferometric observations, we aim to characterize the 0.1-10 au region of the HD 139614 disk further and then identify viable mechanisms for the inner disk clearing. We report the first multiwavelength modeling of the interferometric data acquired on HD 139614 with the VLTI instruments PIONIER, AMBER, and MIDI, complemented by Herschel/PACS photometric measurements. We first performed a geometrical modeling of the new near-infrared interferometric data, followed by radiative transfer modeling of the complete dataset using the code RADMC3D. We confirm the presence of a gap structure in the warm μm-sized dust distribution, extending from about 2.5 au to 6 au, and constrained the properties of the inner dust component: e.g., a radially increasing dust surface density profile, and a depletion in dust of ~103 relative to the outer disk. Since self-shadowing and photoevaporation appears unlikely to be responsible for the au-sized gap of HD 139614, we thus tested if dynamical clearing could be a viable mechanism using hydrodynamical simulations to predict the structure of the gaseous disk. Indeed, a narrow au-sized gap is consistent with the expected effect of the interaction between a single giant planet and the disk. Assuming that small dust grains are well coupled to the gas, we found that an approximately 3 Mjup planet located at ~4.5 au from the star could, in less than 1 Myr, reproduce most of the aspects of the dust surface density profile, while no significant depletion (in gas) occurred in the inner disk, in

[Determination of multi-element contents in gypsum by ICP-AES].

PubMed

Guo, Zhong-bao; Bai, Yong-zhi; Cui, Jin-hua; Mei, Yi-fei; Ma, Zhen-zhu

2014-08-01

The content of multi-element in gypsum was determined by ICP-AES. The sample was pretreated by acid-soluble method or alkali-fusion method. Acid-soluble method is suitable for the determination of CaO, SOs, Al2O3, Fe2O3, MgO, K2O, Na2O, TiO2, P2O5, MnO, SrO and BaO. Alkali-fusion method is suitable for the determination of CaO, SO3, SiO2, Al2O3, Fe2O3, MgO, TiO2, P2O5, MnO, SrO, BaO and B2O3. Different series standard solutions were prepared considering the properties and content of elements and solution matrix. The limit of detection and quantification were confirmed for each element under their best analysis spectral lines. The recoveries of the two pretreatment methods were from 93% to 110%, besides that for TiO2 was 81%-87% as pretreated by acid-soluble method. All RSDs (n=6) of tests were from 0.70%-3.42%. The accuracies of CaO and SO3 with ICP-AES method were less than the chemical analysis method. The determination of CaO and SO3 with ICP-AES method is only suitable for the case of low accuracy requirement. The results showed that the method can be used for the determination of multi-element contents in gypsum, with simple operation, fast analysis and reliable results. Total elements can be analysed with both acid-soluble method and alkali-fusion method.

75 FR 8326 - AES ES Westover, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-24

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER10-712-000] AES ES Westover, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket... proceeding of AES ES Westover, LLC's application for market-based rate authority, with an accompanying rate...

An appraisal of the psychometric properties of the Clinician version of the Apathy Evaluation Scale (AES-C).

PubMed

Clarke, Diana E; Van Reekum, Robert; Patel, Jigisha; Simard, Martine; Gomez, Everlyne; Streiner, David L

2007-01-01

This article examines the psychometric properties of the clinician version of the Apathy Evaluation Scale (AES-C) to determine its ability to characterize, quantify and differentiate apathy. Critical appraisals of the item-reduction processes, effectiveness of the administration, coding and scoring procedures, and the reliability and validity of the scale were carried out. For training, administration and rating of the AES-C, clearer guidelines, including a more standardized list of verbal and non-verbal apathetic cues, are needed. There is evidence of high internal consistency for the scale across studies. In addition, the original study reported good test-retest and inter-rater reliability coefficients. However, there is a lack of replication on these more stable and informative measures of reliability and as such they warrant further investigation. The research evidence confirms that the AES-C shows good discriminant, convergent and criterion validity. However, evidence of its predictive validity is limited. As this aspect of validity refers to the scale's ability to predict future outcomes, which is important for treatment and rehabilitation planning, further assessment of the predictive validity of the AES-C is needed. In conclusion, the AES-C is a reliable and valid measure for the characterization and quantification of apathy. Copyright (c) 2007 John Wiley & Sons, Ltd.

Analysis of high-purity germanium dioxide by ETV-ICP-AES with preliminary concentration of trace elements.

PubMed

Medvedev, Nickolay S; Shaverina, Anastasiya V; Tsygankova, Alphiya R; Saprykin, Anatoly I

2016-08-01

The paper presents a combined technique of germanium dioxide analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES) with preconcentration of trace elements by distilling off matrix and electrothermal (ETV) introduction of the trace elements concentrate into the ICP. Evaluation of metrological characteristics of the developed technique of high-purity germanium dioxide analysis was performed. The limits of detection (LODs) for 25 trace elements ranged from 0.05 to 20ng/g. The accuracy of proposed technique is confirmed by "added-found" («or spiking») experiment and comparing the results of ETV-ICP-AES and ICP-AES analysis of high purity germanium dioxide samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Harmonization in preclinical epilepsy research: A joint AES/ILAE translational initiative.

PubMed

Galanopoulou, Aristea S; French, Jacqueline A; O'Brien, Terence; Simonato, Michele

2017-11-01

Among the priority next steps outlined during the first translational epilepsy research workshop in London, United Kingdom (2012), jointly organized by the American Epilepsy Society (AES) and the International League Against Epilepsy (ILAE), are the harmonization of research practices used in preclinical studies and the development of infrastructure that facilitates multicenter preclinical studies. The AES/ILAE Translational Task Force of the ILAE has been pursuing initiatives that advance these goals. In this supplement, we present the first reports of the working groups of the Task Force that aim to improve practices of performing rodent video-electroencephalography (vEEG) studies in experimental controls, generate systematic reviews of preclinical research data, and develop preclinical common data elements (CDEs) for epilepsy research in animals. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Multiphysics Simulation of Low-Amplitude Acoustic Wave Detection by Piezoelectric Wafer Active Sensors Validated by In-Situ AE-Fatigue Experiment

PubMed Central

Giurgiutiu, Victor

2017-01-01

Piezoelectric wafer active sensors (PWAS) are commonly used for detecting Lamb waves for structural health monitoring application. However, in most applications of active sensing, the signals are of high-amplitude and easy to detect. In this article, we have shown a new avenue of using the PWAS transducer for detecting the low-amplitude fatigue-crack related acoustic emission (AE) signals. Multiphysics finite element (FE) simulations were performed with two PWAS transducers bonded to the structure. Various configurations of the sensors were studied by using the simulations. One PWAS was placed near to the fatigue-crack and the other one was placed at a certain distance from the crack. The simulated AE event was generated at the crack tip. The simulation results showed that both PWAS transducers were capable of sensing the AE signals. To validate the multiphysics simulation results, an in-situ AE-fatigue experiment was performed. Two PWAS transducers were bonded to the thin aerospace test coupon. The fatigue crack was generated in the test coupon which had produced low-amplitude acoustic waves. The low-amplitude fatigue-crack related AE signals were successfully captured by the PWAS transducers. The distance effect on the captured AE signals was also studied. It has been shown that some high-frequency contents of the AE signal have developed as they travel away from the crack. PMID:28817081

A brightness-referenced star identification algorithm for APS star trackers.

PubMed

Zhang, Peng; Zhao, Qile; Liu, Jingnan; Liu, Ning

2014-10-08

Star trackers are currently the most accurate spacecraft attitude sensors. As a result, they are widely used in remote sensing satellites. Since traditional charge-coupled device (CCD)-based star trackers have a limited sensitivity range and dynamic range, the matching process for a star tracker is typically not very sensitive to star brightness. For active pixel sensor (APS) star trackers, the intensity of an imaged star is valuable information that can be used in star identification process. In this paper an improved brightness referenced star identification algorithm is presented. This algorithm utilizes the k-vector search theory and adds imaged stars' intensities to narrow the search scope and therefore increase the efficiency of the matching process. Based on different imaging conditions (slew, bright bodies, etc.) the developed matching algorithm operates in one of two identification modes: a three-star mode, and a four-star mode. If the reference bright stars (the stars brighter than three magnitude) show up, the algorithm runs the three-star mode and efficiency is further improved. The proposed method was compared with other two distinctive methods the pyramid and geometric voting methods. All three methods were tested with simulation data and actual in orbit data from the APS star tracker of ZY-3. Using a catalog composed of 1500 stars, the results show that without false stars the efficiency of this new method is 4~5 times that of the pyramid method and 35~37 times that of the geometric method.

Toward the first stars: hints from the CEMP-no stars

NASA Astrophysics Data System (ADS)

Choplin, A.

2017-12-01

CEMP-no stars are iron-deficient, carbon-rich stars, with no or little s- and r-elements. Because of their very low iron content, they are often considered to be closely linked to the first stars. Their origin is still a matter of debate. Understanding their formation could provide very valuable information on the first stars, early nucleosynthesis, early galactic chemical evolution and first supernovae. The most explored formation scenario for CEMP-no stars suggests that CEMP-no stars formed from the ejecta (wind and/or supernova) of a massive source star, that lived before the CEMP-no star. Here we discuss models of fast rotating massive source stars with and without triggering a late mixing event just before the end of the life of the source star. We find that without this late mixing event, the bulk of observed CEMP-no stars cannot be reproduced by our models. On the opposite, the bulk is reproductible if adding the late mixing event in the source star models.

Asymmetry of inverted-topology repeats in the AE1 anion exchanger suggests an elevator-like mechanism

PubMed Central

Faraldo-Gómez, José D.

2017-01-01

The membrane transporter anion exchanger 1 (AE1), or band 3, is a key component in the processes of carbon-dioxide transport in the blood and urinary acidification in the renal collecting duct. In both erythrocytes and the basolateral membrane of the collecting-duct α-intercalated cells, the role of AE1 is to catalyze a one-for-one exchange of chloride for bicarbonate. After decades of biochemical and functional studies, the structure of the transmembrane region of AE1, which catalyzes the anion-exchange reaction, has finally been determined. Each protomer of the AE1 dimer comprises two repeats with inverted transmembrane topologies, but the structures of these repeats differ. This asymmetry causes the putative substrate-binding site to be exposed only to the extracellular space, consistent with the expectation that anion exchange occurs via an alternating-access mechanism. Here, we hypothesize that the unknown, inward-facing conformation results from inversion of this asymmetry, and we propose a model of this state constructed using repeat-swap homology modeling. By comparing this inward-facing model with the outward-facing experimental structure, we predict that the mechanism of AE1 involves an elevator-like motion of the substrate-binding domain relative to the nearly stationary dimerization domain and to the membrane plane. This hypothesis is in qualitative agreement with a wide range of biochemical and functional data, which we review in detail, and suggests new avenues of experimentation. PMID:29167180

Organizing for empowerment: an interview with AES's Roger Sant and Dennis Bakke. Interview by Suzy Wetlaufer.

PubMed

Sant, R; Bakke, D

1999-01-01

The topic of empowerment is receiving a lot of attention, but how many employees are truly empowered? At the global electricity giant AES Corporation, the answer is all 40,000 of them. In this interview, chairman Roger Sant and CEO Dennis Bakke reflect on their trials and triumphs in creating an exceptional company and explain how their employee-run company works. When they founded AES in 1981, Sant and Bakke set out to create a company where people could have engaging experiences on a daily basis--a company that embodied the principles of fairness, integrity, social responsibility, and fun. Putting those principles into action has created something unique--an ecosystem of real empowerment. What does that system look like? Rather than having a traditional hierarchical chain of command, AES is organized around small teams that are responsible for operations and maintenance. Moreover, AES has eliminated functional departments; there's no corporate marketing division or human resources department. For the system to work, every person must become a well-rounded generalist--a mini-CEO. That, in turn, redefines the jobs of the people at headquarters. Instead of setting strategy and making the "the big decisions," Sant and Bakke act as advisers, guardians of the principles, accountability officers, and chief encouragers. Can other companies successfully adopt the mechanics of such a system? Not unless they first adopt the shared principles that have guided AES since its inception. "Empowerment without values isn't empowerment," says Sant. "It's just technique," adds Bakke.

Simultaneous observations of reaction kinetics, creep behavior, and AE activities during syndeformational antigorite dehydration at high pressures

NASA Astrophysics Data System (ADS)

Kubo, T.; Iwasato, T.; Higo, Y.; Kato, T.; Kaneshima, S.; Uehara, S.; Koizumi, S.; Imamura, M.; Tange, Y.

2015-12-01

Intermediate-depth earthquakes are seismic activities in Wadati-Benioff zone at depths from 60 km to 300 km, where subducting plates deform plastically rather than brittle failure. Although it has been reported that unstable faulting occurred during antigorite dehydration even at higher pressures than ~2 GPa (e.g., Jung et al., 2009), the recent study by Chernak and Hirth (2011) revealed that the syndefromational antigorite dehydration does not produces stick-slip instabilities but stable fault slip. In the present study, we newly developed an AE monitoring system for high-pressure reaction-deformation processes combined with D-DIA and synchrotron monochromatic X-ray to observe reaction kinetics, creep behaviors, and AE activities simultaneously. We applied this technique to investigate shear instability during syndeformational antigorite dehydration. High-pressure deformation experiments were conducted up to ~8 GPa, ~1050 K, and strain rates of 3.4-9.2 x 10-5 s-1 in compression using a D-DIA type apparatus installed at BL-04B1, SPring-8. 50 keV mono X-ray were used to measure reaction kinetics and stress-strain data. To monitor shear instabilities by detecting AEs, six piezoelectric devices were positioned between first and second stage anvils of MA 6-6 type system. We used three kinds of starting materials of polycrystalline antigorite, fine-grained forsterite polycrystal, and two-phase mixtures of antigorite and San Carlos olivine (10%, 30%, and 50%atg). Clear contrasts were observed in AE activities between forsterite and antigorite samples. AE activities detected within the forsterite polycrystal suggested (semi) brittle behaviors at low pressures during the cold compression stage.
Almost no AEs were detected within the antigorite samples during any stages of cold compression, ramping, deformation, and syndeformational dehydration although localized deformation textures were observed in recovered samples. Instead, we detected some AEs outside the sample

Everyone is working together to ease the pressures in A&E.

PubMed

Kimber, Mark

2015-01-27

Nurse consultant Janet Youd, chair of the RCN Emergency Care Association, says nurses struggling to cope with unprecedented pressures in A&E departments should be awarded an extra half day's annual leave (Online News January 8).

Shot peening influence on corrosion resistance of AE21 magnesium alloy.

DOT National Transportation Integrated Search

2010-12-15

"Evaluation of the electrochemical characteristics of the AE21 magnesium alloy is presented in the article. : The surfaces of tested alloys were treated by grinding and grinding followed by sodium bicarbonate shotpeening. : The specimens were evaluat...

A Brightness-Referenced Star Identification Algorithm for APS Star Trackers

PubMed Central

Zhang, Peng; Zhao, Qile; Liu, Jingnan; Liu, Ning

2014-01-01

Star trackers are currently the most accurate spacecraft attitude sensors. As a result, they are widely used in remote sensing satellites. Since traditional charge-coupled device (CCD)-based star trackers have a limited sensitivity range and dynamic range, the matching process for a star tracker is typically not very sensitive to star brightness. For active pixel sensor (APS) star trackers, the intensity of an imaged star is valuable information that can be used in star identification process. In this paper an improved brightness referenced star identification algorithm is presented. This algorithm utilizes the k-vector search theory and adds imaged stars' intensities to narrow the search scope and therefore increase the efficiency of the matching process. Based on different imaging conditions (slew, bright bodies, etc.) the developed matching algorithm operates in one of two identification modes: a three-star mode, and a four-star mode. If the reference bright stars (the stars brighter than three magnitude) show up, the algorithm runs the three-star mode and efficiency is further improved. The proposed method was compared with other two distinctive methods the pyramid and geometric voting methods. All three methods were tested with simulation data and actual in orbit data from the APS star tracker of ZY-3. Using a catalog composed of 1500 stars, the results show that without false stars the efficiency of this new method is 4∼5 times that of the pyramid method and 35∼37 times that of the geometric method. PMID:25299950

Validation of the new trapped environment AE9/AP9/SPM at low Earth orbit

NASA Astrophysics Data System (ADS)

Badavi, Francis F.

2014-09-01

The completion of the international space station (ISS) in 2011 has provided the space research community an ideal proving ground for future long duration human activities in space. Ionizing radiation measurements in ISS form the ideal tool for the validation of radiation environmental models, nuclear transport codes and nuclear reaction cross sections. Indeed, prior measurements on the space transportation system (STS; shuttle) provided vital information impacting both the environmental models and the nuclear transport code developments by indicating the need for an improved dynamic model of the low Earth orbit (LEO) trapped environment. Additional studies using thermo-luminescent detector (TLD), tissue equivalent proportional counter (TEPC) area monitors, and computer aided design (CAD) model of earlier ISS configurations, confirmed STS observations that, as input, computational dosimetry requires an environmental model with dynamic and directional (anisotropic) behavior, as well as an accurate six degree of freedom (DOF) definition of the vehicle attitude and orientation along the orbit of ISS. At LEO, a vehicle encounters exposure from trapped particles and attenuated galactic cosmic rays (GCR). Within the trapped field, a challenge arises from properly estimating the amount of exposure acquired. There exist a number of models to define the intensities of the trapped particles during the solar quiet and active times. At active times, solar energetic particles (SEP) generated by solar flare or coronal mass ejection (CME) also contribute to the exposure at high northern and southern latitudes. Among the more established trapped models are the historic and popular AE8/AP8, dating back to the 1980s, the historic and less popular CRRES electron/proton, dating back to 1990s and the recently released AE9/AP9/SPM. The AE9/AP9/SPM model is a major improvement over the older AE8/AP8 and CRRES models. This model is derived from numerous measurements acquired over four

Star centroiding error compensation for intensified star sensors.

PubMed

Jiang, Jie; Xiong, Kun; Yu, Wenbo; Yan, Jinyun; Zhang, Guangjun

2016-12-26

A star sensor provides high-precision attitude information by capturing a stellar image; however, the traditional star sensor has poor dynamic performance, which is attributed to its low sensitivity. Regarding the intensified star sensor, the image intensifier is utilized to improve the sensitivity, thereby further improving the dynamic performance of the star sensor. However, the introduction of image intensifier results in star centroiding accuracy decrease, further influencing the attitude measurement precision of the star sensor. A star centroiding error compensation method for intensified star sensors is proposed in this paper to reduce the influences. First, the imaging model of the intensified detector, which includes the deformation parameter of the optical fiber panel, is established based on the orthographic projection through the analysis of errors introduced by the image intensifier. Thereafter, the position errors at the target points based on the model are obtained by using the Levenberg-Marquardt (LM) optimization method. Last, the nearest trigonometric interpolation method is presented to compensate for the arbitrary centroiding error of the image plane. Laboratory calibration result and night sky experiment result show that the compensation method effectively eliminates the error introduced by the image intensifier, thus remarkably improving the precision of the intensified star sensors.

Dosimetry of 64Cu-DOTA-AE105, a PET tracer for uPAR imaging.

PubMed

Persson, Morten; El Ali, Henrik H; Binderup, Tina; Pfeifer, Andreas; Madsen, Jacob; Rasmussen, Palle; Kjaer, Andreas

2014-03-01

(64)Cu-DOTA-AE105 is a novel positron emission tomography (PET) tracer specific to the human urokinase-type plasminogen activator receptor (uPAR). In preparation of using this tracer in humans, as a new promising method to distinguish between indolent and aggressive cancers, we have performed PET studies in mice to evaluate the in vivo biodistribution and estimate human dosimetry of (64)Cu-DOTA-AE105. Five mice received iv tail injection of (64)Cu-DOTA-AE105 and were PET/CT scanned 1, 4.5 and 22 h post injection. Volume-of-interest (VOI) were manually drawn on the following organs: heart, lung, liver, kidney, spleen, intestine, muscle, bone and bladder. The activity concentrations in the mentioned organs [%ID/g] were used for the dosimetry calculation. The %ID/g of each organ at 1, 4.5 and 22 h was scaled to human value based on a difference between organ and body weights. The scaled values were then exported to OLINDA software for computation of the human absorbed doses. The residence times as well as effective dose equivalent for male and female could be obtained for each organ. To validate this approach, of human projection using mouse data, five mice received iv tail injection of another (64)Cu-DOTA peptide-based tracer, (64)Cu-DOTA-TATE, and underwent same procedure as just described. The human dosimetry estimates were then compared with observed human dosimetry estimate recently found in a first-in-man study using (64)Cu-DOTA-TATE. Human estimates of (64)Cu-DOTA-AE105 revealed the heart wall to receive the highest dose (0.0918 mSv/MBq) followed by the liver (0.0815 mSv/MBq), All other organs/tissue were estimated to receive doses in the range of 0.02-0.04 mSv/MBq. The mean effective whole-body dose of (64)Cu-DOTA-AE105 was estimated to be 0.0317 mSv/MBq. Relatively good correlation between human predicted and observed dosimetry estimates for (64)Cu-DOTA-TATE was found. Importantly, the effective whole body dose was predicted with very high precision

Role of Cl−–HCO3 − exchanger AE3 in intracellular pH homeostasis in cultured murine hippocampal neurons, and in crosstalk to adjacent astrocytes

PubMed Central

Salameh, Ahlam I.; Hübner, Christian A.

2016-01-01

Key points A polymorphism of human AE3 is associated with idiopathic generalized epilepsy. Knockout of AE3 in mice lowers the threshold for triggering epileptic seizures. The explanations for these effects are elusive.Comparisons of cells from wild‐type vs. AE3–/– mice show that AE3 (present in hippocampal neurons, not astrocytes; mediates HCO3 – efflux) enhances intracellular pH (pHi) recovery (decrease) from alkali loads in neurons and, surprisingly, adjacent astrocytes.During metabolic acidosis (MAc), AE3 speeds initial acidification, but limits the extent of pHi decrease in neurons and astrocytes.AE3 speeds re‐alkalization after removal of MAc in neurons and astrocytes, and speeds neuronal pHi recovery from an ammonium prepulse‐induced acid load.We propose that neuronal AE3 indirectly increases acid extrusion in (a) neurons via Cl– loading, and (b) astrocytes by somehow enhancing NBCe1 (major acid extruder). The latter would enhance depolarization‐induced alkalinization of astrocytes, and extracellular acidification, and thereby reduce susceptibility to epileptic seizures. Abstract The anion exchanger AE3, expressed in hippocampal (HC) neurons but not astrocytes, contributes to intracellular pH (pHi) regulation by facilitating the exchange of extracellular Cl– for intracellular HCO3 –. The human AE3 polymorphism A867D is associated with idiopathic generalized epilepsy. Moreover, AE3 knockout (AE3–/–) mice are more susceptible to epileptic seizure. The mechanism of these effects has been unclear because the starting pHi in AE3–/– and wild‐type neurons is indistinguishable. The purpose of the present study was to use AE3–/– mice to investigate the role of AE3 in pHi homeostasis in HC neurons, co‐cultured with astrocytes. We find that the presence of AE3 increases the acidification rate constant during pHi recovery from intracellular alkaline loads imposed by reducing [CO2]. The presence of AE3 also speeds intracellular

Genotypic characterization of CRF01_AE env genes derived from human immunodeficiency virus type 1-infected patients residing in central Thailand.

PubMed

Utachee, Piraporn; Jinnopat, Piyamat; Isarangkura-Na-Ayuthaya, Panasda; de Silva, Udayanga Chandimal; Nakamura, Shota; Siripanyaphinyo, Uamporn; Wichukchinda, Nuanjun; Tokunaga, Kenzo; Yasunaga, Teruo; Sawanpanyalert, Pathom; Ikuta, Kazuyoshi; Auwanit, Wattana; Kameoka, Masanori

2009-02-01

CRF01_AE is a major subtype of human immunodeficiency virus type 1 (HIV-1) circulating in Southeast Asia, including Thailand. HIV-1 env genes were amplified by polymerase chain reaction from blood samples of HIV-1-infected patients residing in Thailand in 2006, and cloned into the pNL4-3-derived reporter viral construct. Generated envelope protein (Env)-recombinant virus was examined for its infectivity, and then 35 infectious CRF01_AE Env-recombinant viruses were selected. Sequencing analysis revealed that the interclone variation of the deduced amino acid sequences was higher in CRF01_AE env genes isolated in 2006 than in those isolated in the early 1990s, suggesting that env gene variation has been increasing gradually among CRF01_AE viruses prevalent in Thailand. We also examined the characteristics of the deduced amino acid sequences of 35 CRF01_AE env genes. Our results may provide useful information to help in better understanding the genotype of env genes of CRF01_AE viruses currently circulating in Thailand.

Design and application of star map simulation system for star sensors

NASA Astrophysics Data System (ADS)

Wu, Feng; Shen, Weimin; Zhu, Xifang; Chen, Yuheng; Xu, Qinquan

2013-12-01

Modern star sensors are powerful to measure attitude automatically which assure a perfect performance of spacecrafts. They achieve very accurate attitudes by applying algorithms to process star maps obtained by the star camera mounted on them. Therefore, star maps play an important role in designing star cameras and developing procession algorithms. Furthermore, star maps supply significant supports to exam the performance of star sensors completely before their launch. However, it is not always convenient to supply abundant star maps by taking pictures of the sky. Thus, star map simulation with the aid of computer attracts a lot of interests by virtue of its low price and good convenience. A method to simulate star maps by programming and extending the function of the optical design program ZEMAX is proposed. The star map simulation system is established. Firstly, based on analyzing the working procedures of star sensors to measure attitudes and the basic method to design optical system by ZEMAX, the principle of simulating star sensor imaging is given out in detail. The theory about adding false stars and noises, and outputting maps is discussed and the corresponding approaches are proposed. Then, by external programming, the star map simulation program is designed and produced. Its user interference and operation are introduced. Applications of star map simulation method in evaluating optical system, star image extraction algorithm and star identification algorithm, and calibrating system errors are presented completely. It was proved that the proposed simulation method provides magnificent supports to the study on star sensors, and improves the performance of star sensors efficiently.

A Mathematical Model Supports a Key Role for Ae4 (Slc4a9) in Salivary Gland Secretion.

PubMed

Vera-Sigüenza, Elías; Catalán, Marcelo A; Peña-Münzenmayer, Gaspar; Melvin, James E; Sneyd, James

2018-02-01

We develop a mathematical model of a salivary gland acinar cell with the objective of investigating the role of two [Formula: see text] exchangers from the solute carrier family 4 (Slc4), Ae2 (Slc4a2) and Ae4 (Slc4a9), in fluid secretion. Water transport in this type of cell is predominantly driven by [Formula: see text] movement. Here, a basolateral [Formula: see text] adenosine triphosphatase pump (NaK-ATPase) and a [Formula: see text]-[Formula: see text]-[Formula: see text] cotransporter (Nkcc1) are primarily responsible for concentrating the intracellular space with [Formula: see text] well above its equilibrium potential. Gustatory and olfactory stimuli induce the release of [Formula: see text] ions from the internal stores of acinar cells, which triggers saliva secretion. [Formula: see text]-dependent [Formula: see text] and [Formula: see text] channels promote ion secretion into the luminal space, thus creating an osmotic gradient that promotes water movement in the secretory direction. The current model for saliva secretion proposes that [Formula: see text] anion exchangers (Ae), coupled with a basolateral [Formula: see text] ([Formula: see text]) (Nhe1) antiporter, regulate intracellular pH and act as a secondary [Formula: see text] uptake mechanism (Nauntofte in Am J Physiol Gastrointest Liver Physiol 263(6):G823-G837, 1992; Melvin et al. in Annu Rev Physiol 67:445-469, 2005. https://doi.org/10.1146/annurev.physiol.67.041703.084745 ). Recent studies demonstrated that Ae4 deficient mice exhibit an approximate [Formula: see text] decrease in gland salivation (Peña-Münzenmayer et al. in J Biol Chem 290(17):10677-10688, 2015). Surprisingly, the same study revealed that absence of Ae2 does not impair salivation, as previously suggested. These results seem to indicate that the Ae4 may be responsible for the majority of the secondary [Formula: see text] uptake and thus a key mechanism for saliva secretion. Here, by using 'in-silico' Ae2 and Ae4 knockout

Local environmental and meteorological conditions influencing the invasive mosquito Ae. albopictus and arbovirus transmission risk in New York City.

PubMed

Little, Eliza; Bajwa, Waheed; Shaman, Jeffrey

2017-08-01

Ae. albopictus, an invasive mosquito vector now endemic to much of the northeastern US, is a significant public health threat both as a nuisance biter and vector of disease (e.g. chikungunya virus). Here, we aim to quantify the relationships between local environmental and meteorological conditions and the abundance of Ae. albopictus mosquitoes in New York City. Using statistical modeling, we create a fine-scale spatially explicit risk map of Ae. albopictus abundance and validate the accuracy of spatiotemporal model predictions using observational data from 2016. We find that the spatial variability of annual Ae. albopictus abundance is greater than its temporal variability in New York City but that both local environmental and meteorological conditions are associated with Ae. albopictus numbers. Specifically, key land use characteristics, including open spaces, residential areas, and vacant lots, and spring and early summer meteorological conditions are associated with annual Ae. albopictus abundance. In addition, we investigate the distribution of imported chikungunya cases during 2014 and use these data to delineate areas with the highest rates of arboviral importation. We show that the spatial distribution of imported arboviral cases has been mostly discordant with mosquito production and thus, to date, has provided a check on local arboviral transmission in New York City. We do, however, find concordant areas where high Ae. albopictus abundance and chikungunya importation co-occur. Public health and vector control officials should prioritize control efforts to these areas and thus more cost effectively reduce the risk of local arboviral transmission. The methods applied here can be used to monitor and identify areas of risk for other imported vector-borne diseases.

Local environmental and meteorological conditions influencing the invasive mosquito Ae. albopictus and arbovirus transmission risk in New York City

PubMed Central

Bajwa, Waheed; Shaman, Jeffrey

2017-01-01

Ae. albopictus, an invasive mosquito vector now endemic to much of the northeastern US, is a significant public health threat both as a nuisance biter and vector of disease (e.g. chikungunya virus). Here, we aim to quantify the relationships between local environmental and meteorological conditions and the abundance of Ae. albopictus mosquitoes in New York City. Using statistical modeling, we create a fine-scale spatially explicit risk map of Ae. albopictus abundance and validate the accuracy of spatiotemporal model predictions using observational data from 2016. We find that the spatial variability of annual Ae. albopictus abundance is greater than its temporal variability in New York City but that both local environmental and meteorological conditions are associated with Ae. albopictus numbers. Specifically, key land use characteristics, including open spaces, residential areas, and vacant lots, and spring and early summer meteorological conditions are associated with annual Ae. albopictus abundance. In addition, we investigate the distribution of imported chikungunya cases during 2014 and use these data to delineate areas with the highest rates of arboviral importation. We show that the spatial distribution of imported arboviral cases has been mostly discordant with mosquito production and thus, to date, has provided a check on local arboviral transmission in New York City. We do, however, find concordant areas where high Ae. albopictus abundance and chikungunya importation co-occur. Public health and vector control officials should prioritize control efforts to these areas and thus more cost effectively reduce the risk of local arboviral transmission. The methods applied here can be used to monitor and identify areas of risk for other imported vector-borne diseases. PMID:28832586

ALMA detection of the rotating molecular disk wind from the young star HD 163296

NASA Astrophysics Data System (ADS)

Klaassen, P. D.; Juhasz, A.; Mathews, G. S.; Mottram, J. C.; De Gregorio-Monsalvo, I.; van Dishoeck, E. F.; Takahashi, S.; Akiyama, E.; Chapillon, E.; Espada, D.; Hales, A.; Hogerheijde, M. R.; Rawlings, M.; Schmalzl, M.; Testi, L.

2013-07-01

Disk winds have been postulated as a mechanism for angular momentum release in protostellar systems for decades. HD 163296 is a Herbig Ae star surrounded by a disk and has been shown to host a series of HH knots (HH 409) with bow shocks associated with the farthest knots. Here we present ALMA science verification data of CO J = 2-1 and J = 3-2 emission, which are spatially coincident with the blue shifted jet of HH knots, and offset from the disk by -18.6 km s-1. The emission has a double corkscrew morphology and extends more than 10'' from the disk with embedded emission clumps coincident with jet knots. We interpret this double corkscrew as emission from material in a molecular disk wind, and that the compact emission near the jet knots is being heated by the jet that is moving at much higher velocities. We show that the J = 3-2 emission is likely heavily filtered by the interferometer, but the J = 2-1 emission suffers less due to the larger beam and sensitivity to larger scale structures. Excitation analysis suggests temperatures exceeding 900 K in these compact features, with the wind mass, momentum and energy being of order 10-5 M⊙, 10-4 M⊙ km s-1 and 1040 erg, respectively. The high mass loss rate suggests that this star is dispersing the disk faster than it is funneling mass onto the star.

Spectroscopic classification of AT2018aes as a supernova impostor

NASA Astrophysics Data System (ADS)

Andrews, Jennifer; Smith, Nathan; Van Dyk, Schuyler D.

2018-03-01

A visual-wavelength optical spectrum of AT2018aes obtained on UT 2018 Mar 13 (JD 2458190.84) with the Magellan Clay telescope (+ LDSS3 spectrograph, VPH-all grism) reveals a narrow H-alpha emission line with a velocity of 525 km/s, with wings extending to roughly +/-1000 km/s.

Far-infrared properties of flare stars and dM stars

NASA Technical Reports Server (NTRS)

Mullan, D. J.; Stencel, R. E.; Backman, D. E.

1989-01-01

Results are reported from a search of the IRAS data base for flare stars and for a control sample of dM stars. At 12 microns, 70-80 percent of both samples have been detected. The K-12 colors of flare stars are significantly different from those of dM stars: for a given K magnitude, a flare star is about 70 percent brighter at 12 microns than a dM star. At 100 microns, 27 percent of the flare stars which are sources at 12 microns have been detected, while none of the comparable dM stars has been detected. Implications for microflaring are discussed.

X-ray sources associated with young stellar objects in the star formation region CMa R1

NASA Astrophysics Data System (ADS)

Santos-Silva, Thais; Gregorio-Hetem, Jane; Montmerle, Thierry

2013-07-01

In previous works we studied the star formation scenario in the molecular cloud Canis Major R1 (CMa R1), derived from the existence of young stellar population groups near the Be stars Z CMa and GU CMa. Using data from the ROSAT X-ray satellite, having a field-of-view of ~ 1° in diameter, Gregorio-Hetem et al. (2009) discovered in this region young stellar objects mainly grouped in two clusters of different ages, with others located in between. In order to investigate the nature of these objects and to test a possible scenario of sequential star formation in this region, four fields (each 30 arcmin diameter, with some overlap) have been observed with the XMM-Newton satellite, with a sensitivity about 10 times better than ROSAT. The XMM-Newton data are currently under analysis. Preliminary results indicate the presence of about 324 sources, most of them apparently having one or more near-infrared counterparts showing typical colors of young stars. The youth of the X-ray sources was also confirmed by X-ray hardness ratio diagrams (XHRD), in different energy bands, giving an estimate of their Lx/Lbol ratios. In addition to these results, we present a detailed study of the XMM field covering the cluster near Z CMa. Several of these sources were classified as T Tauri and Herbig Ae/Be stars, using optical spectroscopy obtained with Gemini telescopes, in order to validate the use of XHRD applied to the entire sample. This classification is also used to confirm the relation between the luminosities in the near-infrared and X-ray bands expected for the T Tauri stars in CMa R1. In the present work we show the results of the study based on the spectra of about 90 sources found nearby Z CMa. We checked that the X-ray spectra (0.3 to 10 keV) of young objects is different from that observed in field stars and extragalactic objects. Some of the candidates also have light curve showing flares that are typical of T Tauri stars, which confirms the young nature of these X

Aloe-emodin (AE) nanoparticles suppresses proliferation and induces apoptosis in human lung squamous carcinoma via ROS generation in vitro and in vivo.

PubMed

Wu, Yuan-Yuan; Zhang, Jing-Hua; Gao, Jing-Hua; Li, Yong-Sheng

2017-08-26

Human lung squamous cell carcinoma is a deadly cancer for which present therapeutic strategies are inadequate. And traditional chemotherapy results in severe systemic toxicity. Compounds from living organisms often exert a biological activity, triggering several targets, which may be useful for the improvement of novel pharmaceuticals. Aloe-emodin (AE), a well-known natural compound, is a primary component of anthraquinones in Aloe vera and exhibits anti-proliferative and apoptotic effects on various tumor cells. However, the translational and clinical use of AE has been limited owing to its rapid degradation and poor bioavailability. To improve its efficacy, a poly (lactic-co-glycolic acid) based AE nanoparticle formulation (NanoAE) was prepared. Our study indicated that compared to the free AE, nanoAE significantly suppressed cancer cell proliferation, induced cell cycle arrest and apoptosis, evidenced by high cleavage of Caspase-3, poly (ADP-ribose) polymerase (PARP), Caspase-8 and Caspase-9. NanoAE enhanced reactive oxygen species (ROS) production, along with Mitogen-activated protein kinases (MAPKs) activation and PI3K/AKT inactivation. Cell proliferation, apoptosis and MAPKs and PI3K/AKT were dependent on ROS production in nanoAE-treated groups. In vivo, nanoAE exhibited inhibitory effects on the tumor growth with little toxicity. Together, our results indicated that nanoAE might be an effective treatment for human lung squamous cell carcinoma. Copyright © 2017. Published by Elsevier Inc.

New Secure E-mail System Based on Bio-Chaos Key Generation and Modified AES Algorithm

NASA Astrophysics Data System (ADS)

Hoomod, Haider K.; Radi, A. M.

2018-05-01

The E-mail messages exchanged between sender’s Mailbox and recipient’s Mailbox over the open systems and insecure Networks. These messages may be vulnerable to eavesdropping and itself poses a real threat to the privacy and data integrity from unauthorized persons. The E-mail Security includes the following properties (Confidentiality, Authentication, Message integrity). We need a safe encryption algorithm to encrypt Email messages such as the algorithm Advanced Encryption Standard (AES) or Data Encryption Standard DES, as well as biometric recognition and chaotic system. The proposed E-mail system security uses modified AES algorithm and uses secret key-bio-chaos that consist of biometric (Fingerprint) and chaotic system (Lu and Lorenz). This modification makes the proposed system more sensitive and random. The execution time for both encryption and decryption of the proposed system is much less from original AES, in addition to being compatible with all Mail Servers.

Pulsating Stars

NASA Astrophysics Data System (ADS)

Catelan, M.; Smith, H. A.

2015-03-01

This book surveys our understanding of stars which change in brightness because they pulsate. Pulsating variable stars are keys to distance scales inside and beyond the Milky Way galaxy. They test our understanding not only of stellar pulsation theory but also of stellar structure and evolution theory. Moreover, pulsating stars are important probes of the formation and evolution of our own and neighboring galaxies. Our understanding of pulsating stars has greatly increased in recent years as large-scale surveys of pulsating stars in the Milky Way and other Local Group galaxies have provided a wealth of new observations and as space-based instruments have studied particular pulsating stars in unprecedented detail.

Modelling and observations of molecules in discs around young stars

NASA Astrophysics Data System (ADS)

Ilee, John David

2013-04-01

This thesis contains a study of molecules within circumstellar discs around young stars. Firstly, the chemistry of a disc around a young, Class 0 protostar is modelled. Such discs are thought to be massive, and thus experience gravitational instabilities, which produce spiral density waves. These affect the chemistry in three ways; by desorbing molecules from dust grains, by providing extra energy for new reactions to take place, and by mixing the internal structure of the disc to provide a rich chemistry near the midplane. Secondly, high resolution near-infrared spectra of 20 massive young stellar objects are presented. The objects display CO first overtone bandhead emission, which is excited in the conditions expected within circumstellar discs. The emission is modelled using a simple analytic model of a Keplerian disc, and good fits are found to all spectra. On average, the discs correspond to being geometrically thin, spread across a wide range of inclinations. The discs are located within the dust sublimation radius, providing strong evidence that the CO emission originates in small gaseous discs, supporting the scenario in which massive stars form via disc accretion. Finally, medium resolution near-infrared spectra of 5 Herbig Ae/Be stars are presented. The spectra cover both CO bandhead and Br gamma emission. Accretion rates are derived from the measuring the Br gamma emission and through modelling the CO emission, however these accretion rates are found to be inconsistent. High resolution archival data of one of the targets is presented, and it is shown that this CO disc model is unable to fit the high resolution data. Therefore, it is concluded that to properly fit CO spectra, high resolution data are needed, and that previously published information determined from low resolution spectra should be treated with caution.

DCO+, DCN, and N2D+ reveal three different deuteration regimes in the disk around the Herbig Ae star HD 163296

NASA Astrophysics Data System (ADS)

Salinas, V. N.; Hogerheijde, M. R.; Mathews, G. S.; Öberg, K. I.; Qi, C.; Williams, J. P.; Wilner, D. J.

2017-10-01

Context. Deuterium fractionation has been used to study the thermal history of prestellar environments. Their formation pathways trace different regions of the disk and may shed light into the physical structure of the disk, including locations of important features for planetary formation. Aims: We aim to constrain the radial extent of the main deuterated species; we are particularly interested in spatially characterizing the high and low temperature pathways for enhancing deuteration of these species. Methods: We observed the disk surrounding the Herbig Ae star HD 163296 using ALMA in Band 6 and obtained resolved spectral imaging data of DCO+ (J = 3 - 2), DCN (J = 3 - 2) and N2D+ (J = 3 - 2) with synthesized beam sizes of 0.̋53 × 0.̋42, 0.̋53 × 0.̋42, and 0.̋50 × 0.̋39, respectively. We adopted a physical model of the disk from the literature and use the 3D radiative transfer code LIME to estimate an excitation temperature profile for our detected lines. We modeled the radial emission profiles of DCO+, DCN, and N2D+, assuming their emission is optically thin, using a parametric model of their abundances and our excitation temperature estimates. Results: DCO+ can be described by a three-region model with constant-abundance rings centered at 70 AU, 150 AU, and 260 AU. The DCN radial profile peaks at about 60 AU and N2D+ is seen in a ring at 160 AU. Simple models of both molecules using constant abundances reproduce the data. Assuming reasonable average excitation temperatures for the whole disk, their disk-averaged column densities (and deuterium fractionation ratios) are 1.6-2.6×1012 cm-2 (0.04-0.07), 2.9-5.2×1012 cm-2 ( 0.02), and 1.6-2.5×1011 cm-2 (0.34-0.45) for DCO+, DCN, and N2D+, respectively. Conclusions: Our simple best-fit models show a correlation between the radial location of the first two rings in DCO+ and the DCN and N2D+ abundance distributions that can be interpreted as the high and low temperature deuteration pathways regimes. The

Impaired trafficking of human kidney anion exchanger (kAE1) caused by hetero-oligomer formation with a truncated mutant associated with distal renal tubular acidosis.

PubMed

Quilty, Janne A; Cordat, Emmanuelle; Reithmeier, Reinhart A F

2002-12-15

Autosomal dominant distal renal tubular acidosis (dRTA) has been associated with several mutations in the anion exchanger AE1 gene. The effect of an 11-amino-acid C-terminal dRTA truncation mutation (901 stop) on the expression of kidney AE1 (kAE1) and erythroid AE1 was examined in transiently transfected HEK-293 cells. Unlike the wild-type proteins, kAE1 901 stop and AE1 901 stop mutants exhibited impaired trafficking from the endoplasmic reticulum to the plasma membrane as determined by immunolocalization, cell-surface biotinylation, oligosaccharide processing and pulse-chase experiments. The 901 stop mutants were able to bind to an inhibitor affinity resin, suggesting that these mutant membrane proteins were not grossly misfolded. Co-expression of wild-type and mutant kAE1 or AE1 resulted in intracellular retention of the wild-type proteins in a pre-medial Golgi compartment. This dominant negative effect was due to hetero-oligomer formation of the mutant and wild-type proteins. Intracellular retention of kAE1 in the alpha-intercalated cells of the kidney would account for the impaired acid secretion into the urine characteristic of dRTA.

I-Love relations for incompressible stars and realistic stars

NASA Astrophysics Data System (ADS)

Chan, T. K.; Chan, AtMa P. O.; Leung, P. T.

2015-02-01

In spite of the diversity in the equations of state of nuclear matter, the recently discovered I-Love-Q relations [Yagi and Yunes, Science 341, 365 (2013), 10.1126/science.1236462], which relate the moment of inertia, tidal Love number (deformability), and the spin-induced quadrupole moment of compact stars, hold for various kinds of realistic neutron stars and quark stars. While the physical origin of such universality is still a current issue, the observation that the I-Love-Q relations of incompressible stars can well approximate those of realistic compact stars hints at a new direction to approach the problem. In this paper, by establishing recursive post-Minkowskian expansion for the moment of inertia and the tidal deformability of incompressible stars, we analytically derive the I-Love relation for incompressible stars and show that the so-obtained formula can be used to accurately predict the behavior of realistic compact stars from the Newtonian limit to the maximum mass limit.

76 FR 39868 - AES Thames, L.L.C.; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-07

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-3913-000] AES Thames, L.L.C.; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of AES Thames, LLC...

LINFLUX-AE: A Turbomachinery Aeroelastic Code Based on a 3-D Linearized Euler Solver

NASA Technical Reports Server (NTRS)

Reddy, T. S. R.; Bakhle, M. A.; Trudell, J. J.; Mehmed, O.; Stefko, G. L.

2004-01-01

This report describes the development and validation of LINFLUX-AE, a turbomachinery aeroelastic code based on the linearized unsteady 3-D Euler solver, LINFLUX. A helical fan with flat plate geometry is selected as the test case for numerical validation. The steady solution required by LINFLUX is obtained from the nonlinear Euler/Navier Stokes solver TURBO-AE. The report briefly describes the salient features of LINFLUX and the details of the aeroelastic extension. The aeroelastic formulation is based on a modal approach. An eigenvalue formulation is used for flutter analysis. The unsteady aerodynamic forces required for flutter are obtained by running LINFLUX for each mode, interblade phase angle and frequency of interest. The unsteady aerodynamic forces for forced response analysis are obtained from LINFLUX for the prescribed excitation, interblade phase angle, and frequency. The forced response amplitude is calculated from the modal summation of the generalized displacements. The unsteady pressures, work done per cycle, eigenvalues and forced response amplitudes obtained from LINFLUX are compared with those obtained from LINSUB, TURBO-AE, ASTROP2, and ANSYS.

Chandra and HST Observations of the High Energy (X-ray/UV) Radiation Fields for an Evolutionary Sequence of Pre-Main-Sequence Stars

NASA Astrophysics Data System (ADS)

Brown, Alexander; Herczeg, G. J.; Brown, J. M.; Walter, F. M.; Valenti, J.; Ardila, D.; Hillenbrand, L. A.; Edwards, S.; Johns-Krull, C. M.; Alexander, R.; Bergin, E. A.; Calvet, N.; Bethell, T. J.; Ingleby, L.; Bary, J. S.; Audard, M.; Baldovin, C.; Roueff, E.; Abgrall, H.; Gregory, S. G.; Ayres, T. R.; Linsky, J. L.

2010-03-01

Pre-main-sequence (PMS) stars are strong X-ray and UV emitters and the high energy radiation from the central stars directly influences the physical and chemical processes in their protoplanetary disks. Gas and dust in protoplanetary systems are excited by these photons, which are the dominant ionization source for hundreds of AU around the star. X-rays penetrate deep into disks and power complex chemistry on grain surfaces. ``Transitional disks'' are an important short-lived evolutionary stage for PMS stars and protoplanetary systems. These disks have transformed most of the dust and gas in their inner regions into planetesimals or larger solid bodies. As dust disks disappear after ages of roughly 5 Myr high levels of stellar magnetic activity persist and continue to bathe the newly-forming protoplanetary systems with intense high energy radiation. We present new X-ray and UV spectra for a sample of PMS stars at a variety of evolutionary stages, including the classical T Tauri stars DE Tau and DK Tau, the transitional disk stars GM Aur and HD135344B, the Herbig Ae star HD104237, and the weak-lined T Tauri star LkCa4, the Eta Cha cluster [age 7 Myr] members RECX1, RECX-11, and RECX-15, and TW Hya association [age 8 Myr] member TWA-2. These include the first results from our 111 orbit HST Large project and associated X-ray data. New and archival Chandra, XMM, and Swift X-ray spectra and HST COS+STIS FUV spectra are being used to reconstruct the full high energy (X-ray/EUV/FUV/NUV) spectra of these stars, thus allowing detailed modeling of the physics and chemistry of their circumstellar environments. The UV spectra provide improved emission line profiles revealing details of the magnetically-heated plasma and accretion and outflow processes. This work is supported by Chandra grants GO8-9024X, GO9-0015X and GO9-0020B and proposal 11200754 and HST GO grants 11336, 11616, and 11828.

Search for OB stars running away from young star clusters. II. The NGC 6357 star-forming region

NASA Astrophysics Data System (ADS)

Gvaramadze, V. V.; Kniazev, A. Y.; Kroupa, P.; Oh, S.

2011-11-01

Dynamical few-body encounters in the dense cores of young massive star clusters are responsible for the loss of a significant fraction of their massive stellar content. Some of the escaping (runaway) stars move through the ambient medium supersonically and can be revealed via detection of their bow shocks (visible in the infrared, optical or radio). In this paper, which is the second of a series of papers devoted to the search for OB stars running away from young ( ≲ several Myr) Galactic clusters and OB associations, we present the results of the search for bow shocks around the star-forming region NGC 6357. Using the archival data of the Midcourse Space Experiment (MSX) satellite and the Spitzer Space Telescope, and the preliminary data release of the Wide-Field Infrared Survey Explorer (WISE), we discovered seven bow shocks, whose geometry is consistent with the possibility that they are generated by stars expelled from the young (~1-2 Myr) star clusters, Pismis 24 and AH03 J1725-34.4, associated with NGC 6357. Two of the seven bow shocks are driven by the already known OB stars, HD 319881 and [N78] 34. Follow-up spectroscopy of three other bow-shock-producing stars showed that they are massive (O-type) stars as well, while the 2MASS photometry of the remaining two stars suggests that they could be B0 V stars, provided that both are located at the same distance as NGC 6357. Detection of numerous massive stars ejected from the very young clusters is consistent with the theoretical expectation that star clusters can effectively lose massive stars at the very beginning of their dynamical evolution (long before the second mechanism for production of runaway stars, based on a supernova explosion in a massive tight binary system, begins to operate) and lends strong support to the idea that probably all field OB stars have been dynamically ejected from their birth clusters. A by-product of our search for bow shocks around NGC 6357 is the detection of three circular

Expression of metastasis suppressor gene AES driven by a Yin Yang (YY) element in a CpG island promoter and transcription factor YY2.

PubMed

Kakizaki, Fumihiko; Sonoshita, Masahiro; Miyoshi, Hiroyuki; Itatani, Yoshiro; Ito, Shinji; Kawada, Kenji; Sakai, Yoshiharu; Taketo, M Mark

2016-11-01

We recently found that the product of the AES gene functions as a metastasis suppressor of colorectal cancer (CRC) in both humans and mice. Expression of amino-terminal enhancer of split (AES) protein is significantly decreased in liver metastatic lesions compared with primary colon tumors. To investigate its downregulation mechanism in metastases, we searched for transcriptional regulators of AES in human CRC and found that its expression is reduced mainly by transcriptional dysregulation and, in some cases, by additional haploidization of its coding gene. The AES promoter-enhancer is in a typical CpG island, and contains a Yin-Yang transcription factor recognition sequence (YY element). In human epithelial cells of normal colon and primary tumors, transcription factor YY2, a member of the YY family, binds directly to the YY element, and stimulates expression of AES. In a transplantation mouse model of liver metastases, however, expression of Yy2 (and therefore of Aes) is downregulated. In human CRC metastases to the liver, the levels of AES protein are correlated with those of YY2. In addition, we noticed copy-number reduction for the AES coding gene in chromosome 19p13.3 in 12% (5/42) of human CRC cell lines. We excluded other mechanisms such as point or indel mutations in the coding or regulatory regions of the AES gene, CpG methylation in the AES promoter enhancer, expression of microRNAs, and chromatin histone modifications. These results indicate that Aes may belong to a novel family of metastasis suppressors with a CpG-island promoter enhancer, and it is regulated transcriptionally. © 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Do All O Stars Form in Star Clusters?

NASA Astrophysics Data System (ADS)

Weidner, C.; Gvaramadze, V. V.; Kroupa, P.; Pflamm-Altenburg, J.

The question whether or not massive stars can form in isolation or only in star clusters is of great importance for the theory of (massive) star formation as well as for the stellar initial mass function of whole galaxies (IGIMF-theory). While a seemingly easy question it is rather difficult to answer. Several physical processes (e.g. star-loss due to stellar dynamics or gas expulsion) and observational limitations (e.g. dust obscuration of young clusters, resolution) pose severe challenges to answer this question. In this contribution we will present the current arguments in favour and against the idea that all O stars form in clusters.

Evidence for feedback and stellar-dynamically regulated bursty star cluster formation: the case of the Orion Nebula Cluster

NASA Astrophysics Data System (ADS)

Kroupa, Pavel; Jeřábková, Tereza; Dinnbier, František; Beccari, Giacomo; Yan, Zhiqiang

2018-04-01

A scenario for the formation of multiple co-eval populations separated in age by about 1 Myr in very young clusters (VYCs, ages less than 10 Myr) and with masses in the range 600-20 000 M⊙ is outlined. It rests upon a converging inflow of molecular gas building up a first population of pre-main sequence stars. The associated just-formed O stars ionise the inflow and suppress star formation in the embedded cluster. However, they typically eject each other out of the embedded cluster within 106 yr, that is before the molecular cloud filament can be ionised entirely. The inflow of molecular gas can then resume forming a second population. This sequence of events can be repeated maximally over the life-time of the molecular cloud (about 10 Myr), but is not likely to be possible in VYCs with mass <300 M⊙, because such populations are not likely to contain an O star. Stellar populations heavier than about 2000 M⊙ are likely to have too many O stars for all of these to eject each other from the embedded cluster before they disperse their natal cloud. VYCs with masses in the range 600-2000 M⊙ are likely to have such multi-age populations, while VYCs with masses in the range 2000-20 000 M⊙ can also be composed solely of co-eval, mono-age populations. More massive VYCs are not likely to host sub-populations with age differences of about 1 Myr. This model is applied to the Orion Nebula Cluster (ONC), in which three well-separated pre-main sequences in the colour-magnitude diagram of the cluster have recently been discovered. The mass-inflow history is constrained using this model and the number of OB stars ejected from each population are estimated for verification using Gaia data. As a further consequence of the proposed model, the three runaway O star systems, AE Aur, μ Col and ι Ori, are considered as significant observational evidence for stellar-dynamical ejections of massive stars from the oldest population in the ONC. Evidence for stellar

KENNEDY SPACE CENTER, FLA. - At Cape Canaveral Air Force Station, the Space Infrared Telescope Facility (SIRTF) observatory is moved into NASA Spacecraft Hangar AE. SIRTF will remain in the clean room at Hangar AE until it returns to the pad in early August.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - At Cape Canaveral Air Force Station, the Space Infrared Telescope Facility (SIRTF) observatory is moved into NASA Spacecraft Hangar AE. SIRTF will remain in the clean room at Hangar AE until it returns to the pad in early August.

Gravity waves in the thermosphere observed by the AE satellites

NASA Technical Reports Server (NTRS)

Gross, S. H.; Reber, C. A.; Huang, F. T.

1983-01-01

Atmospheric Explorer (AE) satellite data were used to investigate the spectra characteristics of wave-like structure observed in the neutral and ionized components of the thermosphere. Power spectral analysis derived by the maximum entropy method indicate the existence of a broad spectrum of scale sizes for the fluctuations ranging from tens to thousands of kilometers.

[Determination of 24 metal elements and their compounds in air of workplace by ICP-AES].

PubMed

Wang, Xiang; Qiu, Jianguo; Zhao, Zhonglin; Guo, Ying

2014-06-01

To establish a method for determination of the levels of 24 metal elements and their compounds in the air of workplace by inductively coupled plasma-atomic emission spectroscopy (ICP- AES). Sampling filters were digested by microwave, and diluted to 25 ml. Twenty-four elements (Mg, Ni, K, Mo, Zn, Ca, Ba, Pb, Mn, Cd, Cr, Co, Cu, Sr, Bi, Tl, Sn, Li, Sb, Zr, In, V, Y, and Be) were simultaneously measured by ICP-AES. The detection limits for 24 elements were 0.001∼0.029 mg/L; liner correlation coefficient r values were all equal to or above 0.9994; the relative standard derivations were less than 5%; the recovery rates were 91.2%∼103.9%; the degradation rates in 7 days were less than 9.7%. ICP-AES technique is a simple, rapid, accurate, and reliable method, which can be used to measure 24 metal elements and their compounds in the air of workplace.

Medium and large-scale variations of dynamo-induced electric fields from AE ion drift measurements

NASA Technical Reports Server (NTRS)

Coley, W. R.; Mcclure, J. P.

1986-01-01

Current models of the low latitude electric field are largely based on data from incoherent scatter radars. These observations are extended through the addition of the rather extensive high quality electric field measurements from the Ion Drift Meter (IDM) aboard the Atmosphere Explorer (AE) spacecraft. Some preliminary results obtained from the Unified Abstract files of satellite AE-E are presented. This satellite was active from the end of 1975 through June 1981 in various elliptical and circular orbits having an inclination near 20 deg. The resulting data can be examined for the variation of ion drift with latitude, longitude, season, solar cycle, altitude, and magnetic activity. The results presented deal primarily with latitudinal variations of the drift features. Diagrams of data are given and briefly interpreted. The preliminary results presented here indicate that IDM data from the AE and the more recent Dynamics Explorer B spacecraft should continue to disclose some interesting and previously unobserved dynamical features of the low latitude F region.

A comparative validation of the abbreviated Apathy Evaluation Scale (AES-10) with the Neuropsychiatric Inventory apathy subscale against diagnostic criteria of apathy.

PubMed

Leontjevas, Ruslan; Evers-Stephan, Alexandra; Smalbrugge, Martin; Pot, Anne Margriet; Thewissen, Viviane; Gerritsen, Debby L; Koopmans, Raymond T C M

2012-03-01

To compare the Neuropsychiatric Inventory apathy subscale (NPIa) with the abbreviated Apathy Evaluation Scale (AES-10) on discriminant validity and on their performance to distinguish residents as apathetic or nonapathetic. Cross-sectional design. Nursing home. 100 residents of 4 dementia special care units (n = 58) and 3 somatic units (n = 42). Primary professional caregivers were interviewed to score the AES-10 and NPIa. The elderly care physician and the psychologist of each unit examined residents for clinical apathy using diagnostic criteria. The AES-10 and NPIa correlated moderately with each other (r(s) = 0.62, P < .0001). The AES-10 correlated weakly (r(s) = 0.27, P = .024) and the NPIa moderately (r(s) = 0.46, P = .001) with the Cornell Scale for Depression in Dementia. Receiver operating characteristic analysis showed an area under the curve (AUC) of 0.72 (P < .01) for AES-10 and 0.67 (P < .05) for NPIa. The AES-10 produced higher sums of sensitivity and negative predictive value than the NPIa. Explorative analyses revealed that both instruments produced higher scores in dementia independently of having an apathy diagnosis, whereas AUCs were significant in nondementia (AES-10: AUC = 0.88, P < .001; NPIa: AUC = 0.77, P = .023), but not in dementia. Both the AES-10 and NPIa may be used to distinguish apathetic from nonapathetic residents in a heterogeneous sample with and without dementia, or in residents without dementia. The AES-10 may be preferable to the NPIa apathy subscale when ruling out or screening for apathy. The performance of the scales against diagnostic criteria of apathy in dementia need to be further examined. Copyright © 2012 American Medical Directors Association, Inc. Published by Elsevier Inc. All rights reserved.

Bursting star formation and the overabundance of Wolf-Rayet stars

NASA Technical Reports Server (NTRS)

Bodigfee, G.; Deloore, C.

1985-01-01

The ratio of the number of WR-stars to their OB progenitors appears to be significantly higher in some extragalactic systems than in our Galaxy. This overabundance of Wolf-Rayet-stars can be explained as a consequence of a recent burst of star formation. It is suggested that this burst is the manifestation of a long period nonlinear oscillation in the star formation process, produced by positive feedback effects between young stars and the interstellar medium. Star burst galaxies with large numbers of WR-stars must generate gamma - fluxes but due to the distance, all of them are beyond the reach of present-day ray detectors, except probably 30 Dor.

TRIGGERED STAR FORMATION SURROUNDING WOLF-RAYET STAR HD 211853

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Tie; Wu Yuefang; Zhang Huawei

The environment surrounding Wolf-Rayet (W-R) star HD 211853 is studied in molecular, infrared, as well as radio, and H I emission. The molecular ring consists of well-separated cores, which have a volume density of 10{sup 3} cm{sup -3} and kinematic temperature {approx}20 K. Most of the cores are under gravitational collapse due to external pressure from the surrounding ionized gas. From the spectral energy distribution modeling toward the young stellar objects, the sequential star formation is revealed on a large scale in space spreading from the W-R star to the molecular ring. A small-scale sequential star formation is revealed towardmore » core 'A', which harbors a very young star cluster. Triggered star formations are thus suggested. The presence of the photodissociation region, the fragmentation of the molecular ring, the collapse of the cores, and the large-scale sequential star formation indicate that the 'collect and collapse' process functions in this region. The star-forming activities in core 'A' seem to be affected by the 'radiation-driven implosion' process.« less

WNL Stars - the Most Massive Stars in the Universe?

NASA Astrophysics Data System (ADS)

Schnurr, Olivier; Moffat, Anthony F. J.; St-Louis, Nicole; Skalkowski, Gwenael; Niemela, Virpi; Shara, Michael M.

2001-08-01

We propose to carry out an intensive and complete time-dependent spectroscopic study of all 47 known WNL stars in the LMC, an ideal laboratory to study the effect of lower ambient metallicity, Z, on stellar evolution. WNL stars are luminous, cooler WR stars of the nitrogen sequence. This will allow us to: 1) determine the binary frequency. The Roche-lobe overflow (RLOF) mechanism in close binaries is predicted to be responsible for the formation of a significant fraction of WR stars in low Z environments such as the LMC. 2) determine the masses. Since some of these stars (denoted WNL(h) or WNLh) are supposed to be hydrogen-burning and thus main-sequence stellar objects of the highest luminosity, they may be the most massive stars known. 3) study wind-wind collision (WWC) effects in WR+O binaries involving very luminous WNL stars with strong winds. Interesting in itself as a high-energy phenomenon, WWC is in competition with conservative RLOF (i.e. mass transfer to the secondary star), and therefore has to be taken into account in this context.

WNLh Stars - The Most Massive Stars in the Universe?

NASA Astrophysics Data System (ADS)

Schnurr, Olivier; St-Louis, Nicole; Moffat, Anthony F. J.; Foellmi, Cedric

2002-08-01

We propose to conclude our intensive and complete time-dependent spectroscopic study of all 47 known WNL stars in the LMC, an ideal laboratory to study the effect of lower ambient metallicity, Z, on stellar evolution. WNL stars are luminous, cooler WR stars of the nitrogen sequence. This will allow us to: 1) determine the binary frequency. The Roche-lobe overflow (RLOF) mechanism in close binaries is predicted to be responsible for the formation of a significant fraction of WR stars in low Z environments such as the LMC. 2) determine the masses. Since some of these stars (denoted WNL(h) or WNLh) are supposed to be hydrogen-burning and thus main-sequence stellar objects of the highest luminosity, they may be the most massive stars known. 3) study wind-wind collision (WWC) effects in WR+O binaries involving very luminous WNL stars with strong winds. Interesting in itself as a high-energy phenomenon, WWC is in competition with conservative RLOF (i.e. mass transfer to the secondary star), and therefore has to be taken into account in this context.

Nurses in Northern Ireland feel blamed for A&E problems, says RCN.

PubMed

2014-08-05

Emergency nurses in Northern Ireland believe they are being scapegoated for delays in A&E departments when these are the result of broader failings in the health and social care system, the RCN has warned.

Role of adaptor proteins and clathrin in the trafficking of human kidney anion exchanger 1 (kAE1) to the cell surface.

PubMed

Junking, Mutita; Sawasdee, Nunghathai; Duangtum, Natapol; Cheunsuchon, Boonyarit; Limjindaporn, Thawornchai; Yenchitsomanus, Pa-thai

2014-07-01

Kidney anion exchanger 1 (kAE1) plays an important role in acid-base homeostasis by mediating chloride/bicarbornate (Cl-/HCO3-) exchange at the basolateral membrane of α-intercalated cells in the distal nephron. Impaired intracellular trafficking of kAE1 caused by mutations of SLC4A1 encoding kAE1 results in kidney disease - distal renal tubular acidosis (dRTA). However, it is not known how the intracellular sorting and trafficking of kAE1 from trans-Golgi network (TGN) to the basolateral membrane occurs. Here, we studied the role of basolateral-related sorting proteins, including the mu1 subunit of adaptor protein (AP) complexes, clathrin and protein kinase D, on kAE1 trafficking in polarized and non-polarized kidney cells. By using RNA interference, co-immunoprecipitation, yellow fluorescent protein-based protein fragment complementation assays and immunofluorescence staining, we demonstrated that AP-1 mu1A, AP-3 mu1, AP-4 mu1 and clathrin (but not AP-1 mu1B, PKD1 or PKD2) play crucial roles in intracellular sorting and trafficking of kAE1. We also demonstrated colocalization of kAE1 and basolateral-related sorting proteins in human kidney tissues by double immunofluorescence staining. These findings indicate that AP-1 mu1A, AP-3 mu1, AP-4 mu1 and clathrin are required for kAE1 sorting and trafficking from TGN to the basolateral membrane of acid-secreting α-intercalated cells. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Star Polymers.

PubMed

Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

2016-06-22

Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

Identification of stars in a J1744.0 star catalogue Yixiangkaocheng

NASA Astrophysics Data System (ADS)

Ahn, S.-H.

2012-05-01

The stars in the Chinese star catalogue, Yixiangkaocheng, which were edited by the Jesuit astronomer Kögler in AD 1744 and published in AD 1756, are identified with their counterparts in the Hipparcos catalogue. The equinox of the catalogue is confirmed to be J1744.0. By considering the precession of equinox, proper motions and nutation, the star closest to the location of each star in Yixiangkaocheng, having a proper magnitude, is selected as the corresponding identified star. I identified 2848 stars and 13 nebulosities out of 3083 objects in Yixiangkaocheng, and so the identification rate reached 92.80 per cent. I find that the magnitude classification system in Yixiangkaocheng agrees with the modern magnitude system. The catalogue includes dim stars, whose visual magnitudes are larger than 7, but most of these stars have Flamsteed designations. I find that the stars whose declination is lower than -30° have relatively larger offsets and different systematic behaviour from other stars. This indicates that there might be two different sources of stars in Yixiangkaocheng. In particular, I find that μ1 Sco and γ1 Sgr approximately mark the boundary between two different source catalogues. The observer's location, as estimated from these facts, agrees with the latitude of Greenwich where Flamsteed made his observations. The positional offsets between the Yixiangkaocheng stars and the Hipparcos stars are 0.6 arcmin, which implies that the source catalogue of stars with δ > -30° must have come from telescopic observations. Nebulosities in Yixiangkaocheng are identified with a few double stars, o Cet (the variable star, Mira), the Andromeda galaxy, ω Cen and NGC6231. These entities are associated with listings in Halley's Catalogue of the Southern Stars of AD 1679 as well as Flamsteed's catalogue of AD 1690.

The determination of mercury in mushrooms by CV-AAS and ICP-AES techniques.

PubMed

Jarzynska, Grazyna; Falandysz, Jerzy

2011-01-01

This research presents an example of an excellent applied study on analytical problems due to hazardous mercury determination in environmental materials and validity of published results on content of this element in wild growing mushrooms. The total mercury content has been analyzed in a several species of wild-grown mushrooms and some herbal origin certified reference materials, using two analytical methods. One method was commonly known and well validated the cold-vapour atomic absorption spectroscopy (CV-AAS) after a direct sample pyrolysis coupled to the gold wool trap, which was a reference method. A second method was a procedure that involved a final mercury measurement using the inductively-coupled plasma atomic emission spectroscopy (ICP-AES) at λ 194.163 nm, which was used by some authors to report on a high mercury content of a large sets of wild-grown mushrooms. We found that the method using the ICP-AES at λ 194.163 nm gave inaccurate and imprecise results. The results of this study imply that because of unsuitability of total mercury determination using the ICP-AES at λ 194.163 nm, the reports on great concentrations of this metal in a large sets of wild-grown mushrooms, when examined using this method, have to be studied with caution, since data are highly biased.

Massive stars, disks, and clustered star formation

NASA Astrophysics Data System (ADS)

Moeckel, Nickolas Barry

The formation of an isolated massive star is inherently more complex than the relatively well-understood collapse of an isolated, low-mass star. The dense, clustered environment where massive stars are predominantly found further complicates the picture, and suggests that interactions with other stars may play an important role in the early life of these objects. In this thesis we present the results of numerical hydrodynamic experiments investigating interactions between a massive protostar and its lower-mass cluster siblings. We explore the impact of these interactions on the orientation of disks and outflows, which are potentially observable indications of encounters during the formation of a star. We show that these encounters efficiently form eccentric binary systems, and in clusters similar to Orion they occur frequently enough to contribute to the high multiplicity of massive stars. We suggest that the massive protostar in Cepheus A is currently undergoing a series of interactions, and present simulations tailored to that system. We also apply the numerical techniques used in the massive star investigations to a much lower-mass regime, the formation of planetary systems around Solar- mass stars. We perform a small number of illustrative planet-planet scattering experiments, which have been used to explain the eccentricity distribution of extrasolar planets. We add the complication of a remnant gas disk, and show that this feature has the potential to stabilize the system against strong encounters between planets. We present preliminary simulations of Bondi-Hoyle accretion onto a protoplanetary disk, and consider the impact of the flow on the disk properties as well as the impact of the disk on the accretion flow.

A new family of magnetic stars: the Am stars

NASA Astrophysics Data System (ADS)

Blazère, A.; Neiner, C.; Petit, P.; Lignières, F.

2016-12-01

We presented the discovery of an ultra-weak field in three Am stars, β UMa, θ Leo, and Alhena, thanks to ultra-deep spectropolarimetric observations. Two of the three stars of this study shown peculiar magnetic signatures with prominent positive lobes like the one of Sirius A that are not expected in the standard theory of the Zeeman effect. Alhena, contrary to Sirius A, β UMa and θ Leo, show normal signatures. These detections of ultra-weak fields in Am stars suggest the existence of a new family of magnetic intermediate-mass stars: the Am stars. However the various shapes of the signatures required further observation to identify the physical processes at work in these stars. A preliminary explanation is based on microturbulence.

Effect of Spindle Parameters of Woodworking Band Saw on the AE Value of Crack Band Saw Blade in Compound Material Processing (1)

NASA Astrophysics Data System (ADS)

Gao, Jin-gui; Jiang, Zhao-fang; Luo, Lai-peng

2017-04-01

Taking the MJ3210A motion band saw as the research object, the AE value of the band saw blade vibration was obtained by analyzing the VIBSYS vibration signal acquisition and analysis software system in Beijing, and the change of the AE value of the band saw and the crack was found out. The experimental results show that in the MJ3210A sports car sawing machine, the band saw blade with width of 130 mm is used, and the AE value of the cracked band saw blade is well in the high band saw blade AE value. Under the best working condition of the band saw, the band saw blade AE If the value exceeds 104.7 dB (A) above, it means that the band saw blade has at least one crack length greater than 1.38 mm for the crack defect and the need to replace the band saw blade in time. Different species with saw blade of the AE value is different, white pine wood minimum, the largest oak wood; according to a variety of wood processing AE instrument value to determine the band saw blade crack to the situation; so as to fully rational use of band saw blade, The failure and the degree of development to find a new method.

[Determination of diborane in the air of workplace by ICP-AES].

PubMed

Ding, Chun-Guang; Zhang, Jing; Yan, Hui-Fang

2011-06-01

A sampling method was established to collect diborane in the air of workplace and an ICP-AES method was developed to determine the Boron in desorbed solution. Diborane in the air of workplace was collected by solid sorbent tube filled with oxidant impregnated activated carbon. The adsorbed diborane was desorbed into 3% H2O2 aqueous, and then the desorbed Boron was determined by ICP-AES. The sampling efficiency of this method was 99.6% with the desorption efficiency of diborane with 5.660 microg and 56.6 microg spiked were 90.9% and 99.5%, respectively. Both the intra-and inter-precision RSD were less than 8%. The standard curve of this method ranged from 0.1 to 10.0 microg/ml (Boron), and the LOD and LOQ were 0.011 mg/m3 and 0.035 mg/m3 (15L samples) respectively. The method established was suitable for diborane sampling and determination in the air of workplace.

BOREAS AES Five-Day Averaged Surface Meteorological and Upper Air Data

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Strub, Richard; Newcomer, Jeffrey A.

2000-01-01

The Canadian Atmospheric Environment Service (AES) provided BOREAS with hourly and daily surface meteorological data from 23 of the AES meteorological stations located across Canada and upper air data from 1 station at The Pas, Manitoba. Due to copyright restrictions on the full resolution surface meteorological data, this data set contains 5-day average values for the surface parameters. The upper air data are provided in their full resolution form. The 5-day averaging was performed in order to create a data set that could be publicly distributed at no cost. Temporally, the surface meteorological data cover the period of January 1975 to December 1996 and the upper air data cover the period of January 1961 to November 1996. The data are provided in tabular ASCII files, and are classified as AFM-staff data. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

The open cluster IC 1805 and its vicinity: investigation of stars in the Vilnius, IPHAS, 2MASS, and WISE systems

NASA Astrophysics Data System (ADS)

Straižys, V.; Boyle, R. P.; Janusz, R.; Laugalys, V.; Kazlauskas, A.

2013-06-01

The results of CCD photometry in the Vilnius seven-color system down to V = 18 mag are presented for 242 stars in the direction of the young open cluster IC 1805 that is located in the active star-forming region W4 in the Cas OB6 association. Photometric data were used to classify stars into spectral and luminosity classes, and to determine their interstellar reddenings, extinctions and distances. We confirm the CH3OH and H2O maser VLBA parallax results that the cluster is located close to the front side of the Perseus arm, at a distance about 2.0 kpc. In the color-magnitude diagram, zero-age main sequence (ZAMS) stars of the cluster extend to spectral class A0. The extinction values for the majority of the cluster stars are between 2.2 and 2.7 mag, with a mean value of 2.46 mag. This extinction originates mainly between the Sun and the outer edge of the Local arm, in accordance with the distribution of CO clouds. In the Perseus arm and beyond, the extinction was investigated using the classification and reddening determination for A0-F0 stars measured in the r, i, Hα system of the IPHAS survey to r = 19 mag. The extinction AV within the Perseus arm ranges from 2.5-4.5 mag at the front edge to 3.0-5.0 mag at the far edge. Possibly, we have found about 20 early A-type stars located in the Outer arm. The 2MASS JHKs photometry for red giants gives much higher extinction values (up to about 6 mag), which would correspond to the stars located behind dense clouds of both arms. In the area, using the WISE, 2MASS, and IPHAS photometry data, 18 possible young stellar objects (YSOs) of low masses are identified. Six high-mass YSOs (five Ae/Be stars and a F6e star) are known from previous investigations. Full Table 1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/554/A3

Activity and distribution of intracellular carbonic anhydrase II and their effects on the transport activity of anion exchanger AE1/SLC4A1.

PubMed

Al-Samir, Samer; Papadopoulos, Symeon; Scheibe, Renate J; Meißner, Joachim D; Cartron, Jean-Pierre; Sly, William S; Alper, Seth L; Gros, Gerolf; Endeward, Volker

2013-10-15

We have investigated the previously published 'metabolon hypothesis' postulating that a close association of the anion exchanger 1 (AE1) and cytosolic carbonic anhydrase II (CAII) exists that greatly increases the transport activity of AE1. We study whether there is a physical association of and direct functional interaction between CAII and AE1 in the native human red cell and in tsA201 cells coexpressing heterologous fluorescent fusion proteins CAII-CyPet and YPet-AE1. In these doubly transfected tsA201 cells, YPet-AE1 is clearly associated with the cell membrane, whereas CAII-CyPet is homogeneously distributed throughout the cell in a cytoplasmic pattern. Förster resonance energy transfer measurements fail to detect close proximity of YPet-AE1 and CAII-CyPet. The absence of an association of AE1 and CAII is supported by immunoprecipitation experiments using Flag-antibody against Flag-tagged AE1 expressed in tsA201 cells, which does not co-precipitate native CAII but co-precipitates coexpressed ankyrin. Both the CAII and the AE1 fusion proteins are fully functional in tsA201 cells as judged by CA activity and by cellular HCO3(-) permeability (P(HCO3(-))) sensitive to inhibition by 4,4-Diisothiocyano-2,2-stilbenedisulfonic acid. Expression of the non-catalytic CAII mutant V143Y leads to a drastic reduction of endogenous CAII and to a corresponding reduction of total intracellular CA activity. Overexpression of an N-terminally truncated CAII lacking the proposed site of interaction with the C-terminal cytoplasmic tail of AE1 substantially increases intracellular CA activity, as does overexpression of wild-type CAII. These variously co-transfected tsA201 cells exhibit a positive correlation between cellular P(HCO3(-)) and intracellular CA activity. The relationship reflects that expected from changes in cytoplasmic CA activity improving substrate supply to or removal from AE1, without requirement for a CAII-AE1 metabolon involving physical interaction. A functional

[Convertibility of the data determined by ICP-AES and FAAS for soil available K and Na].

PubMed

Zhang, Jian-min; Wang, Meng; Ge, Xiao-ping; Wu, Jian-zhi; Ge, Ying; Li, Shi-peng; Chang, Jie

2009-05-01

In recent years, inductively coupled plasma atomic emission spectrometry (ICP-AES) have been commonly used to determine the soil available K and Na with the extraction solution of HCl-H2SO4, while previous data of soil available K and Na were measured by flame atomic absorption spectrometry (FAAS) with the extraction solution of NH4OAc. In order to utilize previous data, quest for the convertibility of the data determined by ICP-AES and FAAS, and compare the data determined by both methods, the authors chose four types of soil to determine soil available K and Na by ICP-AES and FAAS, respectively. Four types of soil represent grit soil, clay, silt from river and silt from sea, respectively. Soil samples included four types of soil and these samples represent different soil nutrition. The authors analyzed the correlations of two kinds of measured data. The paired samples t-test proves that there was significantly positively correlation between these two methods. The correlation coefficient of the data between these two methods for measuring soil available K is 0.98. The results of soil available K determined by the two methods can be conversed through the formula, y = l.14x + 6.53 (R2 = 0.91, n=24, p < 0.001). As for Na, although there is a significantly positively correlation between these two methods, the slopes of single model of clay and grit soil were different from that of general model. And so the results determined by the two methods can be conversed through different formula according to the types of soil, that is, for clay: y = l.23x + 10.03; for grit soil: y = 3.12x - 23.03; for silt: y = 0.60x. In conclusion, the authors' results showed that previous data of available K and Na measured by FAAS with the extraction solution of NH4OAc were available. And these data were comparable to the data measured by ICP-AES through definite formula The authors' results also suggested that ICP-AES was preferable when many elements were measured at the same time. Under

Induced Star Formation

NASA Astrophysics Data System (ADS)

Kennicutt, Robert C., Jr.

Overview: Induced Star Formation and Interactions Introduction Historical Background: First Hints Systematic Studies: Starbursts Interactions and Nuclear activity IRAS and Ultralumious starburst Galaxies The 1990's: HST, Supercomputers, and the Distant Universe Key Questions and Issues Organization of Lectures Star Formation Properties of Normal Galaxies Observational Techniques Results: Star Formation in Normal Galaxies Interpretation: Star Formation Histories Global Star Formation in interacting Galaxies A Gallery of Interactions and Mergers Star Formation Statistics: Guilt By Association Tests SFRs in Interacting vs Noninteracting Galaxies Kinematic Properties and Regulation of SFRs Induced Nuclear Activity and Star Formation Background: Nuclear Spectra and Classification Nuclear Star Formation and Starbursts Nuclear Star Formation and Interactions Induced AGN Activity: Statistics of Seyfert Galaxies Environments of Quasars Kinematic Clues to the Triggering of AGNs Infrared Luminous Galaxies and Starbursts Background: IR Luminous Galaxies and IRAS Infrared Luminosity Function and Spectra Infrared Structure and Morphology Interstellar Gas X-Ray Emission and Superwinds Optical, UV, and Near-Infrared Spectra Radio Continuum Emission Evidence for Interactions and Mergers The Power Source: Starbursts or Dusty AGNs? Spectral Diagnostics of Starbursts Evolutionary Synthesis Models Applications: Integrated Colors of Interacting Galaxies Applications: Hα Emission, Colors, and SFRs Applications: Spectral Modelling of Evolved Starbursts Infrared Starbursts and the IMF in starbursts Triggering and Regulation of Star Formation: The Problem Introduction: Star Formation as a Nonlinear Process The schmidt Law in Normal Galaxies Star Formation Regimes in Interacting Galaxies Summary Triggering and Regulation of Starbusts: Theoretical Ideas Gravitational Star Formation Thresholds Cloud Collision Models Radial Transport of Gas: Clues from Barred Galaxies Simulations of Starbursts

Detection method based on Kalman filter for high speed rail defect AE signal on wheel-rail rolling rig