Detection of the supercycle in V4140 Sagittarii: First eclipsing ER Ursae Majoris-like object

NASA Astrophysics Data System (ADS)

Kato, Taichi; Hambsch, Franz-Josef; Cook, Lewis M.

2018-06-01

We observed the deeply eclipsing SU UMa-type dwarf nova V4140 Sgr and established the very short supercycle of 69.7(3) d. There were several short outbursts between superoutbursts. These values, together with the short orbital period (0.06143 d), were similar to, but not as extreme as, those of ER UMa-type dwarf novae. The object is thus the first, long sought, eclipsing ER UMa-like object. This ER UMa-like nature can naturally explain the high (apparent) quiescent viscosity and unusual temperature profile in quiescence, which were claimed observational features against the thermal-tidal instability model. The apparently unusual outburst behavior can be reasonably explained by a combination of this ER UMa-like nature and the high orbital inclination, and there is no need to introduce mass transfer bursts from its donor star.

Variability in the Milky Way: Contact Binaries as Diagnostic Tools

NASA Astrophysics Data System (ADS)

de Grijs, R.; Chen, X.; Deng, L.

2017-07-01

We used the 50 cm Binocular Network (50BiN) telescope at Delingha Station (Qinghai Province) of Purple Mountain Observatory (Chinese Academy of Sciences) to obtain simultaneous V- and R-band observations of the old open cluster NGC 188. Our aim was a search for populations of variable stars. We derived light-curve solutions for six W Ursae Majoris (W UMa) eclipsing-binary systems and estimated their orbital parameters. The resulting distance to the W UMas is independent of the physical characteristics of the host cluster. We next determined the current best period-luminosity relations for contact binaries (CBs; scatter σ<0.10 mag). We conclude that CBs can be used as distance tracers with better than 5% uncertainty. We apply our new relations to the 102 CBs in the Large Magellanic Cloud, which yields a distance modulus of (m-M)V,0=18.41±0.20 mag.

The boron abundance of Procyon

NASA Technical Reports Server (NTRS)

Lemke, Michael; Lambert, David L.; Edvardsson, Bengt

1993-01-01

The B I 2496.8 A resonance line and HST/GHRS echelle spectra are used with model atmospheres and synthetic spectra to derive the B abundance of the F dwarfs Procyon (Alpha Canis Minoris), Theta Ursae Majoris, and Iota Pegasi. The B abundance of Theta UMa and Iota Peg is similar to that derived by Boesgaard and Heacox (1978) from the B II resonance line in spectra of A- and B-type stars. These two dwarfs show normal abundances of Li, Be, and B. Procyon, which is highly depleted in Li and Be, is depleted in B by a factor of at least 3. Comparison of the spectra of Procyon and the halo dwarf HD 140283 shows that the B abundance assigned by Duncan et al. (1992) to three halo dwarfs is not greatly overestimated as a result of contamination of the B I line by an unidentified line.

Identifying the Young Low-mass Stars within 25 pc. II. Distances, Kinematics, and Group Membership

NASA Astrophysics Data System (ADS)

Shkolnik, Evgenya L.; Anglada-Escudé, Guillem; Liu, Michael C.; Bowler, Brendan P.; Weinberger, Alycia J.; Boss, Alan P.; Reid, I. Neill; Tamura, Motohide

2012-10-01

We have conducted a kinematic study of 165 young M dwarfs with ages of lsim300 Myr. Our sample is composed of stars and brown dwarfs with spectral types ranging from K7 to L0, detected by ROSAT and with photometric distances of lsim25 pc assuming that the stars are single and on the main sequence. In order to find stars kinematically linked to known young moving groups (YMGs), we measured radial velocities for the complete sample with Keck and CFHT optical spectroscopy and trigonometric parallaxes for 75 of the M dwarfs with the CAPSCam instrument on the du Pont 2.5 m Telescope. Due to their youthful overluminosity and unresolved binarity, the original photometric distances for our sample underestimated the distances by 70% on average, excluding two extremely young (lsim3 Myr) objects found to have distances beyond a few hundred parsecs. We searched for kinematic matches to 14 reported YMGs and identified 10 new members of the AB Dor YMG and 2 of the Ursa Majoris group. Additional possible candidates include six Castor, four Ursa Majoris, two AB Dor members, and one member each of the Her-Lyr and β Pic groups. Our sample also contains 27 young low-mass stars and 4 brown dwarfs with ages lsim150 Myr that are not associated with any known YMG. We identified an additional 15 stars that are kinematic matches to one of the YMGs, but the ages from spectroscopic diagnostics and/or the positions on the sky do not match. These warn against grouping stars together based only on kinematics and that a confluence of evidence is required to claim that a group of stars originated from the same star-forming event. Based on observations collected at the W. M. Keck Observatory, the Canada-France-Hawaii Telescope, the du Pont Telescope at Las Campanas Observatory, and the Subaru Telescope. The Keck Observatory is operated as a scientific partnership between the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation. The CFHT is operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

Superhumps in cataclysmic variables: I. T. Leonis

NASA Astrophysics Data System (ADS)

Lemm, Kristi; Patterson, Joseph; Thomas, Gino; Skillman, David R.

1993-10-01

We report photometry of the dwarf nova T Leonis during its 1993 supermaximum. The principle outburst lasted approximately 20 days, during which large-amplitude superhumps were consistently seen in the light curve. The mean period was 86.7 + or - 0.1 min, about 2.4% longer than the orbital period determined from radial-velocity measurements. Analysis of data obtained during the 1987 supermaximum implies that the superhump period decreased slowly, with dP/dt = - 6 x 10-5, or dP/dm = -0.6 min. mag. These are typical values for SU Ursae Majoris-type dwarf novae. At the end of the outburst, the star suddenly brightened again to magnitude 13, from which it declined on a time scale of about 1 day and without superhumps. It is possible that this event was a normal outburst. This suggests that superoutbursts can trigger normal outbursts, and may explain the 'bump' frequently found in the light curves of SU UMa stars very late in a superoutburst.

Habitable moons around extrasolar giant planets

NASA Technical Reports Server (NTRS)

Williams, D. M.; Kasting, J. F.; Wade, R. A.

1997-01-01

Possible planetary objects have now been discovered orbiting nine different main-sequence stars. These companion objects (some of which might actually be brown dwarfs) all have a mass at least half that of Jupiter, and are therefore unlikely to be hospitable to Earth-like life: jovian planets and brown dwarfs support neither a solid nor a liquid surface near which organisms might dwell. Here we argue that rocky moons orbiting these companions could be habitable if the planet-moon system orbits the parent star within the so-called 'habitable zone', where life-supporting liquid water could be present. The companions to the stars 16 Cygni B and 47 Ursae Majoris might satisfy this criterion. Such a moon would, however, need to be large enough (>0.12 Earth masses) to retain a substantial and long-lived atmosphere, and would also need to possess a strong magnetic field in order to prevent its atmosphere from being sputtered away by the constant bombardment of energetic ions from the planet's magnetosphere.

Habitable moons around extrasolar giant planets.

PubMed

Williams, D M; Kasting, J F; Wade, R A

1997-01-16

Possible planetary objects have now been discovered orbiting nine different main-sequence stars. These companion objects (some of which might actually be brown dwarfs) all have a mass at least half that of Jupiter, and are therefore unlikely to be hospitable to Earth-like life: jovian planets and brown dwarfs support neither a solid nor a liquid surface near which organisms might dwell. Here we argue that rocky moons orbiting these companions could be habitable if the planet-moon system orbits the parent star within the so-called 'habitable zone', where life-supporting liquid water could be present. The companions to the stars 16 Cygni B and 47 Ursae Majoris might satisfy this criterion. Such a moon would, however, need to be large enough (>0.12 Earth masses) to retain a substantial and long-lived atmosphere, and would also need to possess a strong magnetic field in order to prevent its atmosphere from being sputtered away by the constant bombardment of energetic ions from the planet's magnetosphere.

ASCA X-ray spectra of the active single stars Beta Ceti and pi(1) Ursae Majoris

NASA Technical Reports Server (NTRS)

Drake, S. A.; Singh, K. P.; White, N. E.; Simon, Theodore

1994-01-01

We present X-ray spectra obtaiined by ASCA of two single, active stars, the G dwarf pi(1) UMa, and the G9/K0 giant Beta Cet. The spectra of both stars require the presence of at least two plasma components with different temperatures, 0.3-0.4 keV and approximately 0.7 keV, in order for acceptable fits to be obtained. The spectral resolving power and signal-to-noise ratio of the solid state imaging spectrometer (SIS) spectra allow us to formally constrain the coronal abundances of a number of elements. In Beta Cet, we find Mg to be overabundant, while other elements such as O, Ne, and N are underabundant, relative to the solar photospheric values. From the lower signal-to-noise ratio SIS spectrum of pi(1) UMa, we find evidence for underabundances of O, Ne, and Fe. These results are discussed in the context of the present understanding of elemental abundances in solar and stellar coronae.

BE Ursae Majoris: A detached binary with a unique reprocessing spectrum

NASA Technical Reports Server (NTRS)

Steiner, Joao E.; Ferguson, Donald H.; Liebert, James; Tokarz, Susan; Cutri, Roc; Green, Richard F.; Willner, S. P.

1987-01-01

New infrared photometry, optical and UV spectrophotometry, and a photographic ephemeris are presented for the detached binary BE UMa. Results show the primary to be a DO white dwarf with an effective temperature of 80,000 + or - 15,000 K and a mass of 0.6 + or - 0.1 solar masses. No evidence is found for variability of the primary. The main sequence secondary star is shown to be of early M spectral type, with a formal range of M1 to M5 being possible. A reflection effect in reprocessed line and continuum radiation is produced by EUV radiation from the primary incident on the secondary atmosphere. It is suggested that the temperature of the reprocessed component of the secondary's atmosphere is in the 5000 to 8500 K range, and that emission lines of decreasing ionization form deeper in the irradiated envelope. Relatively narrow He II and high excitation metal lines are formed from recombination and continuum fluorescence processes.

X-ray and optical observations of the ultrashort period dwarf nova SW Ursae Majoris - A likely new DQ Herculis star

NASA Technical Reports Server (NTRS)

Shafter, A. W.; Szkody, P.; Thorstensen, J. R.

1986-01-01

Time-resolved X-ray and optical photometric and optical spectroscopic observations of the ultrashort period cataclysmic variable SW UMa are reported. The spectroscopic observations reveal the presence of an s-wave component which is almost in phase with the extreme line wings and presumably the white dwarf. This very unusual phasing in conjunction with the available optical and X-ray data seems to indicate that a region of enhanced emission exists on the opposite side of the disk from the expected location of the hot spot. The photometric observations reveal the presence of a hump in the light curve occurring at an orbital phase which is consistent with the phase at which the region of enhanced line emission is most favorably seen. Changes in the hump amplitude are seen from night to night, and a 15.9 min periodicity is evident in the light curve. The optical and X-ray periodicities suggest that SW UMa is a member of the DQ Her class of cataclysmic variables.

Copernicus observations of the Ap star Epsilon Ursae Majoris

NASA Technical Reports Server (NTRS)

Mallama, A. D.; Molnar, M. R.

1977-01-01

Spectral scans of the Ap star Epsilon UMa made with the Copernicus satellite show strong line blanketing from profuse Cr II and Fe II lines. In the spectral region covering 1900 to 3000 A, about 500 lines are present which suppress the apparent continuum by at least 15-30%. An accurate line-identification list is compiled showing Eu II present in addition to Mn II and Ni II. The identification of Eu II, however, rests on very stringent identification limits for Fe II. If these are relaxed, the existence of Eu II is dubious. There are no broad features in this spectral region which would suggest strong photoionization discontinuities by metals, but one feature near 2137 A might contain the photoionization edge due to Cr I 5S lying 0.94 eV above the ground level. However, a significant correlation between the line-blanketing strength and the amplitude of the OAO-2 ultraviolet light curves was found such that both monotonically increase in the same proportion toward shorter wavelengths. This gives additional strength to the suggestion that variations in the metal line-blanketing cause the observed photometric variations.

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.

New SX Phoenicis Variables in the Globular Cluster NGC 4833

NASA Astrophysics Data System (ADS)

Darragh, A. N.; Murphy, B. W.

2012-07-01

We report the discovery of 6 SX Phoenicis stars in the southern globular cluster NGC 4833. Images were obtained from January through June 2011 with the Southeastern Association for Research in Astronomy 0.6 meter telescope located at Cerro Tololo Interamerican Observatory. The ISIS image subtraction method was used to search for variable stars in the cluster. We confirmed 17 previously cataloged variables and have identified 10 new variables. Of the total number of confirmed variables in our 10×10 arcmin^2 field, we classified 10 RRab variables, with a mean period of 0.69591 days, 7 RRc, with a mean period of 0.39555 days, 2 possible RRe variables with a mean period of 0.30950 days, a W Ursae Majoris contact binary, an Algol-type binary, and the 6 SX Phoenicis stars with a mean period of 0.05847 days. The periods, relative numbers of RRab and RRc variables, and Bailey diagram are indicative of the cluster being of the Oosterhoff type II. We present the phased-light curves, periods of previously known variables and the periods and classifications of the newly discovered variables, and their location on the color-magnitude diagram.

The faint young Sun paradox: an observational test of an alternative solar model

NASA Technical Reports Server (NTRS)

Gaidos, E. J.; Gudel, M.; Blake, G. A.

2000-01-01

We report the results of deep observations at radio (3.6 cm) wavelengths of the nearby solar-type star pi 01 Ursa Majoris with the Very Large Array (VLA) intended to test an alternative theory of solar luminosity evolution. The standard model predicts a solar luminosity only 75% of the present value and surface temperatures below freezing on Earth and Mars at 4 Ga, seemingly in conflict with geologic evidence for liquid water on these planets. An alternative model invokes a compensatory mass loss through a declining solar wind that results in a more consistent early luminosity. The free-free emission from an enhanced wind around nearby young Sun-like stars should be detectable at microwave frequencies. Our observations of pi 01 UMa, a 300 million year-old solar-mass star, place an upper limit on the mass loss rate of 4-5 x 10(-11) M(solar) yr-1. Total mass loss from such a star over 4 Gyr would be less than 6%. If this star is indeed an analog of the early Sun, it casts doubt on the alternative model as a solution to the faint young Sun paradox, particularly for Mars.

New precision orbits of bright double-lined spectroscopic binaries. IX. HD 54371, HR 2692, and 16 ursa majoris

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

Fekel, Francis C.; Williamson, Michael H.; Muterspaugh, Matthew W.

2015-02-01

With extensive sets of new radial velocities we have determined orbital elements for three previously known spectroscopic binaries, HD 54371, HR 2692, and 16 UMa. All three systems have had the lines of their secondaries detected for the first time. The orbital periods range from 16.24 to 113.23 days, and the three binaries have modestly or moderately eccentric orbits. The secondary to primary mass ratios range from 0.50 to 0.64. The orbital dimensions (a{sub 1} sin i and a{sub 2} sin i) and minimum masses (m{sub 1} sin{sup 3} i and m{sub 2} sin{sup 3} i) of the binary componentsmore » all have accuracies of ⩽1%. With our spectroscopic results and the Hipparcos data, we also have determined astrometric orbits for two of the three systems, HR 2692 and 16 UMa. The primaries of HD 54371 and 16 UMa are solar-type stars, and their secondaries are likely K or M dwarfs. The primary of HR 2692 is a late-type subgiant and its secondary is a G or K dwarf. The primaries of both HR 2692 and 16 UMa may be pseudosynchronously rotating, while that of HD 54371 is rotating faster than its pseudosynchronous velocity.« less

Distinct pattern of Th17/Treg cells in pregnant women with a history of unexplained recurrent spontaneous abortion.

PubMed

Qian, Jinfeng; Zhang, Na; Lin, Jing; Wang, Caiyan; Pan, Xinyao; Chen, Lanting; Li, Dajin; Wang, Ling

2018-05-13

The aim of the current study was to determine the pattern of immune cells and related functional molecules in peripheral blood and at the maternal-fetal interface in women with unexplained recurrent spontaneous abortion (URSA). In part I, 155 women were included and divided into four groups: non-pregnant controls with no history of URSA (NPCs), pregnant controls with no history of URSA (PCs), non-pregnant women with a history of URSA (NPUs), and pregnant women with a history of URSA (PUs). Venous blood samples were collected and analyzed. In part II, 35 subjects with URSA and 40 subjects in the early stage of normal pregnancy who chose to undergo an abortion were recruited. Samples of the decidua were collected, and the proportion of immune cells and the expression of related molecules were evaluated. Peripheral regulatory T cells (Treg cells) increased in PCs compared to NPCs, but in women with URSA the flux of Treg cells disappeared when pregnancy occurred. Levels of interleukin-10 (IL-10), cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), and IL-17 and the ratio of Th17/Treg cells in peripheral blood remained stable among the four groups. At the maternal-fetal interface, the percentage of Treg cells, the level of CTLA-4 of CD4 + CD25 + CD127 lo cells and CD4 + Foxp3 + cells were significantly lower in women with URSA compared to controls, respectively. Levels of transforming growth factor-β1 (TGF-β1) mRNA and protein in the decidua significantly decreased in URSA while levels of IL-6 and tumor necrosis factor-ɑ (TNF-ɑ) and the Th17/Treg ratio significantly increased. In conclusion, peripheral Treg cells did not increase in pregnant women with URSA. The decrease in Treg cells and levels of CTLA-4 and TGF-β1 and as well as the increase in levels of IL-6 and TNF-ɑ, and the Th17/Treg ratio at the maternal-fetal interface might contribute to inappropriate maternal-fetal immune tolerance in URSA.

Effects of 1,25(OH)2 vitamin D3 on cytokine production by endometrial cells of women with recurrent spontaneous abortion.

PubMed

Tavakoli, Maryam; Jeddi-Tehrani, Mahmood; Salek-Moghaddam, Alireza; Rajaei, Samira; Mohammadzadeh, Afsaneh; Sheikhhasani, Shahrzad; Kazemi-Sefat, Golnaz-Ensieh; Zarnani, Amir Hassan

2011-09-01

To investigate immunomodulatory effect of 1,25(OH)2 vitamin D3 (1,25(OH)2D3) on cytokine production by endometrial cells of women with unexplained recurrent spontaneous abortion (URSA). In vitro study. Academic research center. Patients with URSA and healthy controls. Treatment with 1,25(OH)2D3. Production of interferon γ (IFN-γ), interleukin-10 (IL-10), transforming growth factor β (TGF-β), IL-17, IL-6, and IL-8 by whole endometrial cells (WECs) and endometrial stromal cells in the presence and absence of 1,25(OH)2D3 and 1α-hydroxylase activity of these cell populations were measured in patients with URSA and healthy controls. 1,25(OH)2D3 interfered with production of cytokines by WECs of the control and URSA groups, except IL-8 which was increased in URSA group. In endometrial stromal cells, 1,25(OH)2D3 down-regulated cytokine production as well with stimulatory effect on the production of TGF-β in patients with URSA. Cytokine profile of WECs from patients with URSA skewed toward TH2 phenotype after treatment with 1,25(OH)2D3. Endometrial cells of both groups had comparable capacity to produce 1,25(OH)2D3. Considering the complex network of immunoregulation at the fetomaternal interface, potential beneficial effects of vitamin D3 in patients with URSA need to be investigated in clinical practice. Comparable levels of 1,25(OH)2D3 production and similar trend of cytokine expression by WECs of URSA and control groups after vitamin D3 treatment reflect the same local metabolic machinery of this hormone. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

A Multimodal Deep Log-Based User Experience (UX) Platform for UX Evaluation

PubMed Central

Ali Khan, Wajahat; Hur, Taeho; Muhammad Bilal, Hafiz Syed; Ul Hassan, Anees; Lee, Sungyoung

2018-01-01

The user experience (UX) is an emerging field in user research and design, and the development of UX evaluation methods presents a challenge for both researchers and practitioners. Different UX evaluation methods have been developed to extract accurate UX data. Among UX evaluation methods, the mixed-method approach of triangulation has gained importance. It provides more accurate and precise information about the user while interacting with the product. However, this approach requires skilled UX researchers and developers to integrate multiple devices, synchronize them, analyze the data, and ultimately produce an informed decision. In this paper, a method and system for measuring the overall UX over time using a triangulation method are proposed. The proposed platform incorporates observational and physiological measurements in addition to traditional ones. The platform reduces the subjective bias and validates the user’s perceptions, which are measured by different sensors through objectification of the subjective nature of the user in the UX assessment. The platform additionally offers plug-and-play support for different devices and powerful analytics for obtaining insight on the UX in terms of multiple participants. PMID:29783712

A Multimodal Deep Log-Based User Experience (UX) Platform for UX Evaluation.

PubMed

Hussain, Jamil; Khan, Wajahat Ali; Hur, Taeho; Bilal, Hafiz Syed Muhammad; Bang, Jaehun; Hassan, Anees Ul; Afzal, Muhammad; Lee, Sungyoung

2018-05-18

The user experience (UX) is an emerging field in user research and design, and the development of UX evaluation methods presents a challenge for both researchers and practitioners. Different UX evaluation methods have been developed to extract accurate UX data. Among UX evaluation methods, the mixed-method approach of triangulation has gained importance. It provides more accurate and precise information about the user while interacting with the product. However, this approach requires skilled UX researchers and developers to integrate multiple devices, synchronize them, analyze the data, and ultimately produce an informed decision. In this paper, a method and system for measuring the overall UX over time using a triangulation method are proposed. The proposed platform incorporates observational and physiological measurements in addition to traditional ones. The platform reduces the subjective bias and validates the user's perceptions, which are measured by different sensors through objectification of the subjective nature of the user in the UX assessment. The platform additionally offers plug-and-play support for different devices and powerful analytics for obtaining insight on the UX in terms of multiple participants.

User Experience Evaluation Methods in Product Development (UXEM'09)

NASA Astrophysics Data System (ADS)

Roto, Virpi; Väänänen-Vainio-Mattila, Kaisa; Law, Effie; Vermeeren, Arnold

High quality user experience (UX) has become a central competitive factor of product development in mature consumer markets [1]. Although the term UX originated from industry and is a widely used term also in academia, the tools for managing UX in product development are still inadequate. A prerequisite for designing delightful UX in an industrial setting is to understand both the requirements tied to the pragmatic level of functionality and interaction and the requirements pertaining to the hedonic level of personal human needs, which motivate product use [2]. Understanding these requirements helps managers set UX targets for product development. The next phase in a good user-centered design process is to iteratively design and evaluate prototypes [3]. Evaluation is critical for systematically improving UX. In many approaches to UX, evaluation basically needs to be postponed until the product is fully or at least almost fully functional. However, in an industrial setting, it is very expensive to find the UX failures only at this phase of product development. Thus, product development managers and developers have a strong need to conduct UX evaluation as early as possible, well before all the parts affecting the holistic experience are available. Different types of products require evaluation on different granularity and maturity levels of a prototype. For example, due to its multi-user characteristic, a community service or an enterprise resource planning system requires a broader scope of UX evaluation than a microwave oven or a word processor that is meant for a single user at a time. Before systematic UX evaluation can be taken into practice, practical, lightweight UX evaluation methods suitable for different types of products and different phases of product readiness are needed. A considerable amount of UX research is still about the conceptual frameworks and models for user experience [4]. Besides, applying existing usability evaluation methods (UEMs) without adaptation to evaluate UX may lead to some scoping issues. Consequently, there is a strong need to put UX evaluation from research into practice.

Another look at AM Herculis - radio-astrometric campaign with the e-EVN at 6 cm

NASA Astrophysics Data System (ADS)

Gawroński, M. P.; Goździewski, K.; Katarzyński, K.; Rycyk, G.

2018-03-01

We conducted radio-interferometric observations of the well-known binary cataclysmic system AM Herculis. This particular system is formed from a magnetic white dwarf (primary) and a red dwarf (secondary), and it is the prototype of so-called polars. Our observations were conducted with the European VLBI Network (EVN) in e-EVN mode at 5 GHz. We obtained six astrometric measurements spanning 1 yr, which make it possible to update the annual parallax for this system with the best precision to date (π = 11.29 ± 0.08 mas), which is equivalent to a distance of 88.6 ± 0.6 pc. The system was observed mostly in the quiescent phase (visual magnitude mv ˜ 15.3), when the radio emission was at the level of about 300 μJy. Our analysis suggests that the radio flux of AM Herculis is modulated with the orbital motion. Such specific properties of the radiation can be explained using an emission mechanism like the scenario proposed for V471 Tau and, in general, for RS CVn-type stars. In this scenario, the radio emission arises near the surface of the red dwarf, where the global magnetic field strength may reach a few kG. We argue that the quiescent radio emission distinguishes AM Herculis and AR Ursae Majoris (a second known persistent radio polar) from other polars, which are systems with a magnetized secondary star.

Searching for Planets Around other Stars

NASA Technical Reports Server (NTRS)

1998-01-01

In this colloquim presentation, Professor of Astronomy, Geoffrey Marcy discusses the discovery of planets orbiting other stars. Using the Doppler shift caused by stellar wobble that is caused by nearby planetary mass, astronomers have been able to infer the existence of Jupiter-sized planets around other stars. Using a special spectrometer at Lick Observatory, the wobble of several stars have been traced over the years required to generate an accurate pattern required to infer the stellar wobble. Professor Marcy, discusses the findings of planets around 47 Ursae Majoris, 16 Cygni B, 51 Pegasus, and 56 Rho 1 Cne. In the case of 56 Rho 1 Cne the planet appears to be close to the star, within 1.5 astronomical units. The observations from the smaller Lick Observatory will be augmented by new observations from the larger telescope at the Kek observatory. This move will allow observations of smaller planets, as opposed to the massive planets thus far discovered. The astronomers also hope to observe smaller stars with the Kek data. Future spaceborne observations will allow the discovery of even smaller planets. A spaceborne interferometer is in the planning stages, and an even larger observatory, called the Terrestrial Planet Finder, is hoped for. Professor Marcy shows artists' renderings of two of the planets thus far discovered. He also briefly discusses planetary formation and shows slides of both observations from the Orion Nebula and models of stellar system formation.

[Association between the C46T polymorphism of coagulation factor Ⅻ gene and the involvement of factor Ⅻ activity in patients with unexplained recurrent spontaneous abortion].

PubMed

Jin, Y H; Shen, X L; Wang, M S; Xu, X M; Liu, M N; Zhao, Z S; Zheng, J Y

2016-08-25

To explore the association between the C46T polymorphism of coagulation factor Ⅻ (FⅫ) gene and the involvement of FⅫ activity (FⅫ:C) in patients with unexplained recurrent spontaneous abortion (URSA), and to elucidate its role in the pathogenesis of URSA. This study included 203 patients with URSA (URSA group) and 171 healthy women with at least one child and no history of infertility or miscarriage (control group) in the southern area of Zhejiang Province. The C46T polymorphism of the FⅫ gene was analyzed with matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS) in all subjects. The values of prothrombin time, activated partial thromboplastin time (APTT), fibrinogen, FⅫ:C and other coagulant parameters were determined. The frequency distribution of the wild-type (CC), heterozygote (CT), homozygote (TT) genotypes and C and T alleles were compared between the patients and controls. A comprehensive analysis of association was conducted between C46T genotypes and the FⅫ:C levels in URSA patients. The CC, CT, TT genotypes of the FⅫ gene were observed in 7 (3.4%, 7/203), 83 (40.9%, 83/203) and 113 (55.7%, 113/203) patients with URSA versus 7 (4.1%, 7/171), 46 (26.9%, 46/171) and 118 (69.0%, 118/171) controls. The frequency of CT in the patients with URSA was significantly higher than that in controls, but the frequency of TT in the patients was lower than that in controls (χ(2)=7.939, OR=1.884, 95%CI: 1.210-2.935, P<0.05). The frequencies of allele C and allele T were observed in 97 (23.9%, 97/406) and 309 (76.1%, 309/406) patients with URSA versus 60 (17.5%, 60/342) and 282 (82.5%, 282/342) controls. The distribution frequency of allele T in URSA group was lower than that in control group (χ(2)=4.510, OR=1.475, 95%CI: 1.029-2.115, P<0.05). The FⅫ: C levels in the patients were (102±13)% in CC genotype, (78±11)% in CT genotype and (59±9)% in TT genotype, respectively. The differences of the FⅫ: C levels between the CC and CT, CT and TT, CC and TT genotypes in the patients were significant (all P<0.05). The low level of FⅫ:C maybe result from the T allele of the FⅫ gene in URSA patients. The CT genotype might be relative to the pathogenesis of URSA in a Chinese Han female population from the southern area of Zhejiang province.

Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. 3; Measurement for URSA Minor

NASA Technical Reports Server (NTRS)

Piatek, Slawomir; Pryor, Carlton; Bristow, Paul; Olszewski, Edward W.; Harris, Hugh C.; Mateo, Mario; Minniti, Dante; Tinney, Christopher G.

2005-01-01

This article presents a measurement of the proper motion of the Ursa Minor dwarf spheroidal galaxy determined from images taken with the Hubble Space Telescope in two distinct fields. Each field contains a quasi-stellar object that serves as the "reference point". Integrating the motion of Ursa Minor in a realistic potential for the Milky Way produces orbital elements. The perigalacticon and apogalacticon are 40 (10, 76) and 89 (78, 160) kpc, respectively, where the values in the parentheses represent the 95% confidence intervals derived from Monte Carlo experiments. The eccentricity of the orbit is 0.39 (0.09, 0.79), and the orbital period is 1.5 (1.1, 2.7) Gyr. The orbit is retrograde and inclined by 124 degrees (94 deg, 36 deg ) to the Galactic plane. Ursa Minor is not a likely member of a proposed stream of galaxies on similar orbits around the Milky Way, nor is the plane of its orbit coincident with a recently proposed planar alignment of galaxies around the Milky Way. Comparing the orbits of Ursa Minor and Carina shows no reason for the different star formation histories of these two galaxies. Ursa Minor must contain dark matter to have a high probability of having survived disruption by the Galactic tidal force until the present.

Using virtual reality to assess user experience.

PubMed

Rebelo, Francisco; Noriega, Paulo; Duarte, Emília; Soares, Marcelo

2012-12-01

The aim of this article is to discuss how user experience (UX) evaluation can benefit from the use of virtual reality (VR). UX is usually evaluated in laboratory settings. However, considering that UX occurs as a consequence of the interaction between the product, the user, and the context of use, the assessment of UX can benefit from a more ecological test setting. VR provides the means to develop realistic-looking virtual environments with the advantage of allowing greater control of the experimental conditions while granting good ecological validity. The methods used to evaluate UX, as well as their main limitations, are identified.The currentVR equipment and its potential applications (as well as its limitations and drawbacks) to overcome some of the limitations in the assessment of UX are highlighted. The relevance of VR for UX studies is discussed, and a VR-based framework for evaluating UX is presented. UX research may benefit from a VR-based methodology in the scopes of user research (e.g., assessment of users' expectations derived from their lifestyles) and human-product interaction (e.g., assessment of users' emotions since the first moment of contact with the product and then during the interaction). This article provides knowledge to researchers and professionals engaged in the design of technological interfaces about the usefulness of VR in the evaluation of UX.

Optical–Mid-infrared Period–Luminosity Relations for W UMa-type Contact Binaries Based on Gaia DR 1: 8% Distance Accuracy

NASA Astrophysics Data System (ADS)

Chen, Xiaodian; Deng, Licai; de Grijs, Richard; Wang, Shu; Feng, Yuting

2018-06-01

W Ursa Majoris (W UMa)-type contact binary systems (CBs) are useful statistical distance indicators because of their large numbers. Here, we establish (orbital) period–luminosity relations (PLRs) in 12 optical to mid-infrared bands (GBVRIJHK s W1W2W3W4) based on 183 nearby W UMa-type CBs with accurate Tycho–Gaia parallaxes. The 1σ dispersion of the PLRs decreases from optical to near- and mid-infrared wavelengths. The minimum scatter, 0.16 mag, implies that W UMa-type CBs can be used to recover distances to 7% precision. Applying our newly determined PLRs to 19 open clusters containing W UMa-type CBs demonstrates that the PLR and open cluster CB distance scales are mutually consistent to within 1%. Adopting our PLRs as secondary distance indicators, we compiled a catalog of 55,603 CB candidates, of which 80% have distance estimates based on a combination of optical, near-infrared, and mid-infrared photometry. Using Fourier decomposition, 27,318 high-probability W UMa-type CBs were selected. The resulting 8% distance accuracy implies that our sample encompasses the largest number of objects with accurate distances within a local volume with a radius of 3 kpc available to date. The distribution of W UMa-type CBs in the Galaxy suggests that in different environments, the CB luminosity function may be different: larger numbers of brighter (longer-period) W UMa-type CBs are found in younger environments.

A long-term optical and X-ray ephemeris of the polar EK Ursae Majoris

NASA Astrophysics Data System (ADS)

Beuermann, K.; Diese, J.; Paik, S.; Ploch, A.; Zachmann, J.; Schwope, A. D.; Hessman, F. V.

2009-11-01

Aims: We searched for long-term period changes in the polar EK UMa using new optical data and archival X-ray/EUV data. Methods: An optical ephemeris was derived from data taken remotely with the MONET/N telescope and compared with the X-ray ephemeris based on Einstein, ROSAT, and EUVE data. A three-parameter fit to the combined data sets yields the epoch, the period, and the phase offset between the optical minima and the X-ray absorption dips. An added quadratic term is insignificant and sets a limit to the period change. Results: The derived linear ephemeris is valid over 30 years and the common optical and X-ray period is P = 0.0795440225(24) days. There is no evidence of long-term O-C variations or a period change over the past 17 years (ΔP = -0.14 ± 0.50 ms). We suggest that the observed period is the orbital period and that the system is tightly synchronized. The limit on ΔP and the phase constancy of the bright part of the light curve indicate that O-C variations of the type seen in the polars DP Leo and HU Aqr or the pre-CV NN Ser do not seem to occur in EK UMa. The X-ray dips lag the optical minima by 9.5° ± 0.7° in azimuth, providing some insight into the accretion geometry.

Automated classification of periodic variable stars detected by the wide-field infrared survey explorer

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

Masci, Frank J.; Grillmair, Carl J.; Cutri, Roc M.

2014-07-01

We describe a methodology to classify periodic variable stars identified using photometric time-series measurements constructed from the Wide-field Infrared Survey Explorer (WISE) full-mission single-exposure Source Databases. This will assist in the future construction of a WISE Variable Source Database that assigns variables to specific science classes as constrained by the WISE observing cadence with statistically meaningful classification probabilities. We have analyzed the WISE light curves of 8273 variable stars identified in previous optical variability surveys (MACHO, GCVS, and ASAS) and show that Fourier decomposition techniques can be extended into the mid-IR to assist with their classification. Combined with other periodicmore » light-curve features, this sample is then used to train a machine-learned classifier based on the random forest (RF) method. Consistent with previous classification studies of variable stars in general, the RF machine-learned classifier is superior to other methods in terms of accuracy, robustness against outliers, and relative immunity to features that carry little or redundant class information. For the three most common classes identified by WISE: Algols, RR Lyrae, and W Ursae Majoris type variables, we obtain classification efficiencies of 80.7%, 82.7%, and 84.5% respectively using cross-validation analyses, with 95% confidence intervals of approximately ±2%. These accuracies are achieved at purity (or reliability) levels of 88.5%, 96.2%, and 87.8% respectively, similar to that achieved in previous automated classification studies of periodic variable stars.« less

RZ Leonis Minoris bridging between ER Ursae Majoris-type dwarf nova and nova-like system

NASA Astrophysics Data System (ADS)

Kato, Taichi; Ishioka, Ryoko; Isogai, Keisuke; Kimura, Mariko; Imada, Akira; Miller, Ian; Masumoto, Kazunari; Nishino, Hirochika; Kojiguchi, Naoto; Kawabata, Miho; Sakai, Daisuke; Sugiura, Yuki; Furukawa, Hisami; Yamamura, Kenta; Kobayashi, Hiroshi; Matsumoto, Katsura; Wang, Shiang-Yu; Chou, Yi; Ngeow, Chow-Choong; Chen, Wen-Ping; Panwar, Neelam; Lin, Chi-Sheng; Hsiao, Hsiang-Yao; Guo, Jhen-Kuei; Lin, Chien-Cheng; Omarov, Chingis; Kusakin, Anatoly; Krugov, Maxim; Starkey, Donn R.; Pavlenko, Elena P.; Antonyuk, Kirill A.; Sosnjvskij, Aleksei A.; Antonyuk, Oksana I.; Pit, Nikolai V.; Baklanov, Alex V.; Babina, Julia V.; Itoh, Hiroshi; Padovan, Stefano; Akazawa, Hidehiko; Kafka, Stella; de Miguel, Enrique; Pickard, Roger D.; Kiyota, Seiichiro; Shugarov, Sergey Yu.; Chochol, Drahomir; Krushevska, Viktoriia; Sekeráš, Matej; Pikalova, Olga; Sabo, Richard; Dubovsky, Pavol A.; Kudzej, Igor; Ulowetz, Joseph; Dvorak, Shawn; Stone, Geoff; Tordai, Tamás; Dubois, Franky; Logie, Ludwig; Rau, Steve; Vanaverbeke, Siegfried; Vanmunster, Tonny; Oksanen, Arto; Maeda, Yutaka; Kasai, Kiyoshi; Katysheva, Natalia; Morelle, Etienne; Neustroev, Vitaly V.; Sjoberg, George

2016-12-01

We observed RZ LMi, which is renowned for its extremely short (˜19 d) supercycle and is a member of a small, unusual class of cataclysmic variables called ER UMa-type dwarf novae, in 2013 and 2016. In 2016, the supercycles of this object substantially lengthened in comparison to the previous measurements to 35, 32, and 60 d for three consecutive superoutbursts. We consider that the object virtually experienced a transition to the nova-like state (permanent superhumper). This observed behavior reproduced the prediction of the thermal-tidal instability model extremely well. We detected a precursor in the 2016 superoutburst and detected growing (stage A) superhumps with a mean period of 0.0602(1) d in 2016 and in 2013. Combined with the period of superhumps immediately after the superoutburst, the mass ratio is not as small as in WZ Sge-type dwarf novae, having orbital periods similar to RZ LMi. By using least absolute shrinkage and selection operator (Lasso) two-dimensional power spectra, we detected possible negative superhumps with a period of 0.05710(1) d. We estimated an orbital period of 0.05792 d, which suggests a mass ratio of 0.105(5). This relatively large mass ratio is even above that of ordinary SU UMa-type dwarf novae, and it is also possible that the exceptionally high mass-transfer rate in RZ LMi may be a result of a stripped secondary with an evolved core in a system evolving toward an AM CVn-type object.

[Association of methionine synthase reductase gene polymorphism with unexplained recurrent spontaneous abortion].

PubMed

Guo, Qian-nan; Liao, Shi-xiu; Kang, Bing; Zhang, Ju-xin; Wang, Rui-li; Ding, Xue-bing; Zhang, Wei-hua

2012-10-01

To explore the relationship between the polymorphism of methionine synthase reductase (MTRR) A66G and the susceptibility to unexplained repeated spontaneous abortion (URSA). Total of 200 Henan Han couples with URSA (URSA group) and 76 Henan Han healthy couples without URSA (control group) were enrolled in this study. Their MTRR A66G genotypes were determined by PCR restriction fragment length polymorphism (PCR-RFLP). (1) The allele frequencies of MTRR A66G: the frequencies of allele A and allele G in URSA group were 76.5% (153/200) in husband and 72.8% (146/200) in wife, 23.5% (47/200) in husband and 27.2% (54/200) in wife, respectively. The frequencies of allele A and allele G in control group were 78.9% (60/76) in husband and 78.3% (59/76) in wife, 21.1% (16/76) in husband and 21.7% (16/76) in wife, respectively. The frequencies of allele A and allele G were not significantly different between female and male subjects within the same experimental group (P > 0.05), and also there were not significantly different between the same gender subjects at URAS and control groups (P > 0.05). (2) The genotype frequencies of MTRR A66G: the frequencies of genotype AA, AG and GG in URSA group were 57.0% (114/200) in husband and 52.0% (104/200) in wife, 39.0% (78/200) in husband and 41.5% (83/200) in wife, 4.0% (8/200) in husband and 6.5% (13/200) in wife, prepectively. The frequencies of genotype AA, AG and GG in control group were 59.2% (45/76) in husband and 59.2% (50/76) in wife, 39.5% (30/76) in husband and 38.2% (29/76) in wife; 1.3% (1/76) in husband and 2.6% (2/76) in wife, prepectively. The frequencies of genotype AA, AG and GG were not significantly different between female and male subjects within the same group (P > 0.05), and also there were not significantly different between the same gender subjects at URSA and control groups (P > 0.05).(3)Combined genotype of couples: the combined genotype frequencies of GG + GG, GG + AG, GG + AA, AG + AG, AG + AA and AA + AA in URSA group were 1.0% (2/200), 2.5% (5/200), 6.0% (12/200), 20.0% (40/200), 38.0% (76/200), and 32.5% (65/200), prepectively; the combined genotype frequencies in control group were 0, 1.3% (1/76), 2.6% (2/76), 17.1% (13/76), 42.1% (32/76), 36.8% (28/76), prepectively. The combined genotype analysis between the two groups were also not significantly different (P > 0.05). The polymorphism of MTRR A66G gene was not associated with the susceptibility to URSA (P > 0.05), and so it was not the inherited genetic risk factor of URSA.

Mission Planning for Heterogeneous UxVs Operating in a Post-Disaster Urban Environment

DTIC Science & Technology

2017-09-01

FOR HETEROGENEOUS UxVs OPERATING IN A POST -DISASTER URBAN ENVIRONMENT by Choon Seng Leon Mark Tan September 2017 Thesis Advisor: Oleg...September 2017 3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE MISSION PLANNING FOR HETEROGENEOUS UxVs OPERATING IN A POST ...UxVs OPERATING IN A POST -DISASTER URBAN ENVIRONMENT Choon Seng Leon Mark Tan Civilian Engineer, ST Aerospace Ltd., Singapore B. Eng (Hons

[Study on the relationship of MTHFR polymorphisms with unexplained recurrent spontaneous abortion].

PubMed

Li, Xiao-mei; Zhang, You-zhong; Xu, Yan-xue; Jiang, Sen

2004-02-01

To assess the relationship of methylenetetrahydrofolate reductase (MTHFR) C677T genotypes to unexplained recurrent spontaneous abortion (URSA). This study included two groups:57 currently non-pregnant women with a history of URSA (URSA group), and 50 currently non-pregnant women with a history of having given birth to at least one live baby and without any history of spontaneous abortion, still-born fetus, placental thrombosis and intrauterine growth retardation(IUGR)(control group). The fasting serum-Hcy was measured with high pressure liquid chromatography. Folic acid and vitamin B(12) were detected by radioimmune assay; antiphospholipid antibody (ACA) was detected by ELISA. MTHFR C677T gene polymorphisms were detected by the technique of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). C/C genotype in URSA group was significantly lower than that in control group, the total mutant T allele frequency was significantly higher than that in control group. There was no significant difference in respect of "age, rural area/city, period, primary/secondary abortion" between the genotype distributions of MTHFR C677T. The T/T genotype and C/T+T/T genotypes frequencies for "abortion times>or=3" were higher than those for "abortion time <3". MTHFR C677T gene polymorphism is a genetic risk factor for URSA.

Discovery and Biochemical Characterization of the UDP-Xylose Biosynthesis Pathway in Sphaerobacter thermophilus.

PubMed

Gu, Bin; Laborda, Pedro; Wei, Shuang; Duan, Xu-Chu; Song, Hui-Bo; Liu, Li; Voglmeir, Josef

2016-01-01

The biosynthesis of UDP-xylose requires the stepwise oxidation/ decarboxylation of UDP-glucose, which is catalyzed by the enzymes UDPglucuronic acid dehydrogenase (UGD) and UDP-xylose synthase (UXS). UDPxylose biosynthesis is ubiquitous in animals and plants. However, only a few UGD and UXS isoforms of bacterial origin have thus far been biochemically characterized. Sphaerobacter thermophilus DSM 20745 is a bacterium isolated from heated sewage sludge, and therefore can be a valuable source of thermostable enzymes of biotechnological interest. However, no biochemical characterizations of any S. thermophilus enzymes have yet been reported. Herein, we describe the cloning and characterization of putative UGD (StUGD) and UXS (StUXS) isoforms from this organism. HPLC- and plate reader-based activity tests of the recombinantly expressed StUGD and StUXS showed that they are indeed active enzymes. Both StUGD and StUXS showed a temperature optimum of 70°C, and a reasonable thermal stability up to 60°C. No metal ions were required for enzymatic activities. StUGD had a higher pH optimum than StUXS. The simple purification procedures and the thermotolerance of StUGD and StUXS make them valuable biocatalysts for the synthesis of UDP-glucuronic acid and UDP-xylose at elevated temperatures. The biosynthetic potential of StUGD was further exemplified in a coupled enzymatic reaction with an UDP-glucuronosyltransferase, allowing the glucuronylation of the natural model substrate bilirubin.

Ursa Major: ot losya do medvedya %t Ursa Major: from elk to bear

NASA Astrophysics Data System (ADS)

Lushnikova, A. V.

In the article material from various cultural and linguistic sources (Indo-European - Slavic, Indo-Iranian; Uralo-Altaic, Tungus, Ancient Egyptian, Babylonian) is used in order to trace up the chronology of the designation of Ursa Majopr, a constellation which has been playing an important role for people different regions since ancient times. It was used for observing of the visible yearly motion of the Sun, for working out seasonal changes; being a circumpolar and non-hiding behind the horizon it has been perceived as a symbol of immortality, its peculiar positional change during a year lay down in plot of the Uralo-Siberian myths about a cosmic hunt for the Elk, myths about deluge. Data from Uralo-Siberian mythology are analyzed. Designations of Ursa Major in the form of a horned hoofed animal such as elk, deer, cow (Uralo-Altaic, Tungus, Slavic, Indo-Iranian languages; Ancient Greece, Crete, Ancient Egypt) and connected with it (or derived from it) denominations and images of "enclosed space" - "vehicle for travelling and carrying goods" (a wagon, a boat) - "instrument for hunting-fishing, a ritual thing" - "household construction" are taken in consideration. The conclusion is made that the transition of the Ursa Major designation from elk to bear could follow the general tendency to shift from so-called matriarchy to patriarchy, to substitute female deities with male ones, which was reflected "in the rise" of the predatory animal cults (not earlier than II mil. B.C.). To prove this, lexical examples of resemblance and coincidences in designation of homed hoofed (elk, deer) and predatory (bear, wolf) animals should be analyzed. Such a goal-directed investigation of the chronology of Ursa Major designations has never been carried out.

Enhanced ergonomics approaches for product design: a user experience ecosystem perspective and case studies.

PubMed

Xu, Wei

2014-01-01

This paper first discusses the major inefficiencies faced in current human factors and ergonomics (HFE) approaches: (1) delivering an optimal end-to-end user experience (UX) to users of a solution across its solution lifecycle stages; (2) strategically influencing the product business and technology capability roadmaps from a UX perspective and (3) proactively identifying new market opportunities and influencing the platform architecture capabilities on which the UX of end products relies. In response to these challenges, three case studies are presented to demonstrate how enhanced ergonomics design approaches have effectively addressed the challenges faced in current HFE approaches. Then, the enhanced ergonomics design approaches are conceptualised by a user-experience ecosystem (UXE) framework, from a UX ecosystem perspective. Finally, evidence supporting the UXE, the advantage and the formalised process for executing UXE and methodological considerations are discussed. Practitioner Summary: This paper presents enhanced ergonomics approaches to product design via three case studies to effectively address current HFE challenges by leveraging a systematic end-to-end UX approach, UX roadmaps and emerging UX associated with prioritised user needs and usages. Thus, HFE professionals can be more strategic, creative and influential.

Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. III. Measurement for Ursa Minor

NASA Astrophysics Data System (ADS)

Piatek, Slawomir; Pryor, Carlton; Bristow, Paul; Olszewski, Edward W.; Harris, Hugh C.; Mateo, Mario; Minniti, Dante; Tinney, Christopher G.

2005-07-01

This article presents a measurement of the proper motion of the Ursa Minor dwarf spheroidal galaxy determined from images taken with the Hubble Space Telescope in two distinct fields. Each field contains a quasi-stellar object that serves as the ``reference point.'' The measured proper motion for Ursa Minor, expressed in the equatorial coordinate system, is (μα,μδ)=(-50+/-17,22+/-16) mas century-1. Removing the contributions of the solar motion and the motion of the local standard of rest yields the proper motion in the Galactic rest frame: (μGrfα,μGrfδ)=(-8+/-17,38+/-16) mas century-1. The implied space velocity with respect to the Galactic center has a radial component of Vr=-75+/-44 km s-1 and a tangential component of Vt=144+/-50 km s-1. Integrating the motion of Ursa Minor in a realistic potential for the Milky Way produces orbital elements. The perigalacticon and apogalacticon are 40 (10, 76) and 89 (78, 160) kpc, respectively, where the values in the parentheses represent the 95% confidence intervals derived from Monte Carlo experiments. The eccentricity of the orbit is 0.39 (0.09, 0.79), and the orbital period is 1.5 (1.1, 2.7) Gyr. The orbit is retrograde and inclined by 124° (94°, 136°) to the Galactic plane. Ursa Minor is not a likely member of a proposed stream of galaxies on similar orbits around the Milky Way, nor is the plane of its orbit coincident with a recently proposed planar alignment of galaxies around the Milky Way. Comparing the orbits of Ursa Minor and Carina shows no reason for the different star formation histories of these two galaxies. Ursa Minor must contain dark matter to have a high probability of having survived disruption by the Galactic tidal force until the present. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

WFPC2 Observations of the URSA Minor Dwarf Spheroidal Galaxy

NASA Technical Reports Server (NTRS)

Mighell, Kenneth J.; Burke, Christopher J.

1999-01-01

We present our analysis of archival Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) observations in F555W (approximately V) and F814W (approximately I) of the central region of the Ursa Minor dwarf spheroidal galaxy. The V versus V - I color-magnitude diagram features a sparsely populated blue horizontal branch, a steep thin red giant branch, and a narrow subgiant branch. The main sequence reaches approximately 2 magnitudes below the main-sequence turnoff (V(sup UMi, sub TO) approximately equals 23.27 +/- 0.11 mag) of the median stellar population. We compare the fiducial sequence of the Galactic globular cluster M92 (NGC 6341). The excellent match between Ursa Minor and M92 confirms that the median stellar population of the UMi dSph galaxy is metal poor ([Fe/H](sub UMi) approximately equals [Fe/H](sub M92) approximately equals -2.2 dex) and ancient (age(sub UMi)approximately equalsage(sub M92) approximately equals 14 Gyr). The B - V reddening and the absorption in V are estimated to be E(B - V) = 0.03 +/- 0.01 mag and A(sup UMi, sub V) = 0.09 +/- 0.03 mag. A new estimate of the distance modulus of Ursa Minor, (m - M)(sup UMi, sub 0) = 19.18 +/- 0.12 mag, has been derived based on fiducial-sequence fitting M92 [DELTA.V(sub UMi - M92) = 4.60 +/- 0.03 mag and DELTA(V - I)(sub UMi - M92) = 0.010 +/- 0.005 mag] and the adoption of the apparent V distance modulus for M92 of (m - M)(sup M92, sub V) = 14.67 +/- 0.08 mag (Pont et al. 1998, A&A, 329, 87). The Ursa Minor dwarf spheroidal galaxy is then at a distance of 69 +/- 4 kpc from the Sun. These HST observations indicate that Ursa Minor has had a very simple star formation history consisting mainly of a single major burst of star formation about 14 Gyr ago which lasted approximately < 2 Gyr. While we may have missed minor younger stellar populations due to the small field-of-view of the WFPC2 instrument, these observations clearly show that most of the stars in the central region Ursa Minor dwarf spheroidal galaxy are ancient. If the ancient Galactic globular clusters, like M92, formed concurrently with the early formation of the Milky Way galaxy itself, then the Ursa Minor dwarf spheroidal is probably as old as the Milky Way.

Expression of GRIM-19 in unexplained recurrent spontaneous abortion and possible pathogenesis.

PubMed

Yang, Yang; Cheng, Laiyang; Deng, Xiaohui; Yu, Hongling; Chao, Lan

2018-05-08

Is aberrant expression of gene associated with retinoid-interferon-induced mortality-19 (GRIM-19) associated with unexplained recurrent spontaneous abortion (URSA)? GRIM-19 deficiency may regulate regulatory T cell/ T helper 17 cell (Treg/Th17) balance partly through reactive oxygen species (ROS) - mammalian target of rapamycin (mTOR) signaling axis in URSA. Immunological disorders may cause impaired maternal immune tolerance to the fetus and result in fetal rejection. The differentiation of Treg and Th17 cells is controlled by phosphoinositide 3-kinase (PI3K)/Akt/mTOR signaling pathway. GRIM-19 participates in the immune response, but its role in URSA is largely unknown. The current study included 28 URSA patients and 30 non-pregnant healthy women. The proportion of Treg and Th17 cells in peripheral blood of URSA patients and control subjects were assessed with flow cytometry. The expression of GRIM-19 in peripheral blood lymphocytes (PBLs) was measured with quantitative real-time PCR and western blot analysis. Furthermore, the ROS level in the PBLs of URSA patients and control subjects were assessed by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining. Then, Akt/mTOR expression in the PBLs was measured. Downregulation of GRIM-19 in Jurkat cells was performed by specific small interfering RNA (siRNA). Then, intracellular ROS production and the expression of p-mTOR, which is known to enhance Th17 differentiation and decrease Treg cell differentiation, were detected. Finally, N-acetylcysteine (NAC) was used to decrease the intracellular ROS level, and the expression of p-mTOR was measured. The proportion of Treg cells was reduced in URSA patients, whereas the proportion of Th17 cells was increased. The expression of GRIM-19 was significantly lower in PBLs of URSA patients. Furthermore, there is a considerable increase in intracellular ROS production and a high level of p-Akt and p-mTOR expression in the PBLs of URSA patients compared with the control subjects. In parallel to this, downregulation of GRIM-19 in the Jurkat cells by siRNA results in an increased ROS production and an increased expression of p-mTOR. Importantly, the upregulation of p-mTOR resulting from GRIM-19 loss was significantly reversed in the cells treatment with ROS inhibitor N-acetyl-L-cysteine (NAC), indicating that ROS was indeed required for GRIM-19 depletion induced p-mTOR expression. None. A large number of researches have confirmed that the differentiation of Treg and Th17 cells is controlled by PI3K/Akt/mTOR signaling pathway. We have not shown the regulatory role of ROS and PI3K/Akt/mTOR in Treg and Th17 differentiation in this study. Our study has demonstrated that GRIM-19 deficiency may play a role in regulating Treg/Th17 balance partly through ROS - mTOR signaling axis in URSA. The present study offers a new perspective to the roles of GRIM-19 in immunoregulation. This work was supported by the National Natural Science Foundation of China (grant numbers 81571511, 81701528, 81370711 and 30901603), the Shandong Provincial Natural Science Foundation (grant number ZR2017PH052 and ZR2013HM090) and the Science Foundation of Qilu Hospital of Shandong University, Fundamental Research Funds of Shandong University (grant numbers 2015QLQN50 and 2015QLMS24). The authors declare that there is no conflict of interest that could prejudice the impartiality of the present research.

NSVS 7051868: A system in a key evolutionary stage. First multi-color photometric study

NASA Astrophysics Data System (ADS)

Barani, C.; Martignoni, M.; Acerbi, F.

2017-01-01

The first CCD photometric complete light curves of the eclipsing binary NSVS 7051868 were obtained during six nights in January 2016 in the B, V and Ic bands using the 0.25 m telescope of the Stazione Astronomica Betelgeuse in Magnago, Italy. These observations confirm the short period (P = 0.517 days) variation found by Shaw and collaborators in their online list (http://www.physast.uga.edu/ jss/nsvs/) of periodic variable stars found in the Northern Sky Variability Survey. The light curves were modelled using the Wilson-Devinney code and the elements obtained from this analysis are used to compute the physical parameters of the system in order to study its evolutionary status. A grid of solutions for several fixed values of mass ratio was calculated. A reasonable fit of the synthetic light curves of the data indicate that NSVS 7051868 is an A-subtype W Ursae Majoris contact binary system, with a low mass ratio of q = 0.22, a degree of contact factor f = 35.5% and inclination i = 85°. Our light curves shows a time of constant light in the secondary eclipse of approximately 0.1 in phase. The light curve solution reveals a component temperature difference of about 700 K. Both the value of the fill-out factor and the temperature difference suggests that NSVS 7051868 is a system in a key evolutionary stage of the Thermal Relaxation Oscillation theory. The distance to NSVS 7051868 was calculated as 180 pc from this analysis, taking into account interstellar extinction.

3D interactive augmented reality-enhanced digital learning systems for mobile devices

NASA Astrophysics Data System (ADS)

Feng, Kai-Ten; Tseng, Po-Hsuan; Chiu, Pei-Shuan; Yang, Jia-Lin; Chiu, Chun-Jie

2013-03-01

With enhanced processing capability of mobile platforms, augmented reality (AR) has been considered a promising technology for achieving enhanced user experiences (UX). Augmented reality is to impose virtual information, e.g., videos and images, onto a live-view digital display. UX on real-world environment via the display can be e ectively enhanced with the adoption of interactive AR technology. Enhancement on UX can be bene cial for digital learning systems. There are existing research works based on AR targeting for the design of e-learning systems. However, none of these work focuses on providing three-dimensional (3-D) object modeling for en- hanced UX based on interactive AR techniques. In this paper, the 3-D interactive augmented reality-enhanced learning (IARL) systems will be proposed to provide enhanced UX for digital learning. The proposed IARL systems consist of two major components, including the markerless pattern recognition (MPR) for 3-D models and velocity-based object tracking (VOT) algorithms. Realistic implementation of proposed IARL system is conducted on Android-based mobile platforms. UX on digital learning can be greatly improved with the adoption of proposed IARL systems.

Gas Removal in the Ursa Minor Galaxy: Linking Hydrodynamics and Chemical Evolution Models

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

Caproni, Anderson; Lanfranchi, Gustavo Amaral; Baio, Gabriel Henrique Campos

2017-04-01

We present results from a non-cosmological, three-dimensional hydrodynamical simulation of the gas in the dwarf spheroidal galaxy Ursa Minor. Assuming an initial baryonic-to-dark-matter ratio derived from the cosmic microwave background radiation, we evolved the galactic gas distribution over 3 Gyr, taking into account the effects of the types Ia and II supernovae. For the first time, we used in our simulation the instantaneous supernovae rates derived from a chemical evolution model applied to spectroscopic observational data of Ursa Minor. We show that the amount of gas that is lost in this process is variable with time and radius, being themore » highest rates observed during the initial 600 Myr in our simulation. Our results indicate that types Ia and II supernovae must be essential drivers of the gas loss in Ursa Minor galaxy (and probably in other similar dwarf galaxies), but it is ultimately the combination of galactic winds powered by these supernovae and environmental effects (e.g., ram-pressure stripping) that results in the complete removal of the gas content.« less

Man o' War Mutation in UDP-α-D-Xylose Synthase Favors the Abortive Catalytic Cycle and Uncovers a Latent Potential for Hexamer Formation

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

Walsh, Jr., Richard M.; Polizzi, Samuel J.; Kadirvelraj, Renuka

The man o’ war (mow) phenotype in zebrafish is characterized by severe craniofacial defects due to a missense mutation in UDP-α-D-xylose synthase (UXS), an essential enzyme in proteoglycan biosynthesis. The mow mutation is located in the UXS dimer interface ~16 Å away from the active site, suggesting an indirect effect on the enzyme mechanism. We have examined the structural and catalytic consequences of the mow mutation (R236H) in the soluble fragment of human UXS (hUXS), which shares 93% sequence identity with the zebrafish enzyme. In solution, hUXS dimers undergo a concentration-dependent association to form a tetramer. Sedimentation velocity studies showmore » that the R236H substitution induces the formation of a new hexameric species. Using two new crystal structures of the hexamer, we show that R236H and R236A substitutions cause a local unfolding of the active site that allows for a rotation of the dimer interface necessary to form the hexamer. The disordered active sites in the R236H and R236A mutant constructs displace Y231, the essential acid/base catalyst in the UXS reaction mechanism. The loss of Y231 favors an abortive catalytic cycle in which the reaction intermediate, UDP-α-D-4-keto-xylose, is not reduced to the final product, UDP-α-D-xylose. Surprisingly, the mow-induced hexamer is almost identical to the hexamers formed by the deeply divergent UXS homologues from Staphylococcus aureus and Helicobacter pylori (21% and 16% sequence identity, respectively). The persistence of a latent hexamer-building interface in the human enzyme suggests that the ancestral UXS may have been a hexamer.« less

Arcturus and the Bears

NASA Astrophysics Data System (ADS)

Antonello, E.

2009-08-01

Arcturus is the brightest star in Bootes. The ancient Greek name Arktouros means Bear Guard. The star, however, is not close to Ursa Maior (Big She-Bear) and Ursa Minor (Little She-Bear), as the name would suggest. This curious discrepancy could be explained by the star proper motion, assuming the name Bear Guard is a remote cultural heritage. The proper motion analysis could allow us to get an insight also into an ancient myth regarding Ursa Maior. Though we cannot explain scientifically such a myth, some interesting suggestions can be obtained about its possible origin, in the context of the present knowledge of the importance of the cult of the bear both during the Palaeolithic times and for several primitive populations of modern times, as shown by the ethnological studies.

Optical and Infrared Spectral Features of Nova Canis Majoris 2018

NASA Astrophysics Data System (ADS)

Rudy, Richard; Mauerhan, Jon; Crawford, Kirk; Russell, Ray; Wiktorowicz, Sloane

2018-04-01

Optical and IR spectra from 0.47-2.5 microns (resolution: 5-30 angstroms) of Nova Canis Majoris (CBET 4499), were obtained 2018 April 21.14 (UT) with the Aerospace Corporation's 1.0 m telescope using its Visible and Infrared Imaging Spectrograph (VNIRIS).

Bridging the Gap between User Experience Research and Design in Industry: An Analysis of Two Common Communication Tools--Personas and Scenarios

ERIC Educational Resources Information Center

Putnam, Cynthia

2010-01-01

User experience (UX) research in the design of technology products utilizes human-centered design (HCD) methods to summarize and explain pertinent information about end users to designers. However, UX researchers cannot effectively communicate the needs and goals of users if designers do not find UX research (a) easy to integrate into design…

Second-Order Characteristic Methods for Advection-Difusion Equations and Comparison to Other Schemes

DTIC Science & Technology

1997-01-01

ow boundary conditions for equation are described by the following formulation Z b a Ux tnwixdx Z b a t V U DUx x t n wix x...dx Z b a Ux tnwixdx Z b a t V U DUx x t n wix xdx Z b a t fx tn fx tn wixdx where the trial function Ux

Draco

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

(the Dragon; abbrev. Dra, gen. Draconis; area 1083 sq. deg.) A northern constellation which lies between Ursa Major and Cepheus, and encloses Ursa Minor on three sides. The center of the constellation culminates at midnight in May, though part of it is on the meridian from mid-February to late July. Draco represents the dragon Ladon in Greek mythology, which guarded the golden apple tree that was...

Potential involvement of placental AhR in unexplained recurrent spontaneous abortion.

PubMed

Wu, Y; Chen, X; Chang, X; Huang, Y J; Bao, S; He, Q; Li, Y; Zheng, J; Duan, T; Wang, K

2016-01-01

Recurrent spontaneous abortion (RSA) is a common complication of pregnancy. Recent studies have demonstrated that the aryl hydrocarbon receptor (AhR) might play important roles in establishing and maintaining early pregnancy. In this study, we found that placental AhR protein levels were significantly lower and placental CYP1A1 mRNA levels were higher in unexplained RSA (URSA) patients than in control subjects. The results of immunohistochemical analyzes showed that placental AhR was expressed in syncytiotrophoblast cells and that the level of AhR was markedly lower in these cells in URSA subjects than in control subjects. β-Naphthoflavone (β-NF, an AhR ligand) at 5μM significantly inhibited proliferation and migration in HTR-8/SVneo cells and was associated with the activation of AhR. Moreover, overexpressing AhR in JAR cells significantly increased CYP1A1 mRNA levels and inhibited cell migration. These results indicate that AhR is highly activated in URSA placentas and that the activation of AhR in the placenta might impair trophoblast cell proliferation and migration, possibly leading to the occurrence of URSA. Copyright © 2015 Elsevier Inc. All rights reserved.

Switching the JLab Accelerator Operations Environment from an HP-UX Unix-based to a PC/Linux-based environment

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

Mcguckin, Theodore

2008-10-01

The Jefferson Lab Accelerator Controls Environment (ACE) was predominantly based on the HP-UX Unix platform from 1987 through the summer of 2004. During this period the Accelerator Machine Control Center (MCC) underwent a major renovation which included introducing Redhat Enterprise Linux machines, first as specialized process servers and then gradually as general login servers. As computer programs and scripts required to run the accelerator were modified, and inherent problems with the HP-UX platform compounded, more development tools became available for use with Linux and the MCC began to be converted over. In May 2008 the last HP-UX Unix login machinemore » was removed from the MCC, leaving only a few Unix-based remote-login servers still available. This presentation will explore the process of converting an operational Control Room environment from the HP-UX to Linux platform as well as the many hurdles that had to be overcome throughout the transition period (including a discussion of« less

The Ursa Major cluster of galaxies - III. Optical observations of dwarf galaxies and the luminosity function down to MR=-11

NASA Astrophysics Data System (ADS)

Trentham, Neil; Tully, R. Brent; Verheijen, Marc A. W.

2001-07-01

Results are presented of a deep optical survey of the Ursa Major cluster, a spiral-rich cluster of galaxies at a distance of 18.6Mpc which contains about 30 per cent of the light but only 5 per cent of the mass of the nearby Virgo cluster. Fields around known cluster members and a pattern of blind fields along the major and minor axes of the cluster were studied with mosaic CCD cameras on the Canada-France-Hawaii Telescope. The dynamical crossing time for the Ursa Major cluster is only slightly less than a Hubble time. Most galaxies in the local Universe exist in similar moderate-density environments. The Ursa Major cluster is therefore a good place to study the statistical properties of dwarf galaxies, since this structure is at an evolutionary stage representative of typical environments, yet has enough galaxies that reasonable counting statistics can be accumulated. The main observational results of our survey are as follows. (i) The galaxy luminosity function is flat, with a logarithmic slope α=-1.1 for -17

Undergraduate Research at SETI in Astrobiology

NASA Astrophysics Data System (ADS)

Kress, Monika; Phillips, C.; DeVore, E.; Hubickyj, O.

2012-05-01

The SETI Institute and San Jose State University (SJSU) have begun a partnership (URSA: Undergraduate Research at the SETI Institute in Astrobiology) in which undergraduate science and engineering majors from SJSU participate in research at the SETI Institute during the academic year. We are currently in our second year of the three-year NASA-funded grant. The goal of this program is to expose future scientists, engineers and educators to the science of astrobiology and to NASA in general, and by so doing, to prepare them for the transition to their future career in the Silicon Valley or beyond. The URSA students are mentored by a SETI Institute scientist who conducts research at the SETI Institute headquarters or nearby at NASA Ames Research Center. The SETI Institute is a private, nonprofit organization dedicated to scientific research, education and public outreach. Its mission is to explore, understand and explain the origin, nature and prevalence of life in the universe. SJSU is a large urban public university that serves the greater Silicon Valley area in California. Students at SJSU come from diverse ethnic, cultural and socioeconomic backgrounds. Many of them face financial pressures that force them to pursue part-time work. URSA students are paid to work for 10 hours/week during the academic year, and also participate in monthly group meetings where they practice their presentation skills and discuss future plans. We encourage underserved and underrepresented students, including women, minority, and those who are the first in their family to go to college, to apply to the URSA program and provide ongoing mentoring and support as needed. While preparing students for graduate school is not a primary goal, some of our students have gone on to MS or PhD programs or plan to do so. The URSA program is funded by NASA EPOESS.

Preliminary elements of the low mass ratio and moderate fill-out factor VSX J045718.3+405643 (GSC 02898-02901)

NASA Astrophysics Data System (ADS)

Acerbi, F.; Martignoni, M.; Barani, C.

2018-05-01

We present the results of our investigation of the geometrical parameters of the W UMa-type binary system VSX J045718.3+405643 (short name VSX J0457) based on new CCD B, V and Ic light curves. Our observations were carried out during six nights in November and December 2016 using the 0.25 m telescope of the Stazione Astronomica Betelgeuse in Magnago, Northern Italy. Six new times of minima and light elements have been determined and the observed light curves were analysed using the Wilson-Devinney code. The output model reveals that the system is a contact binary of A-Subtype of the W Ursae Majoris systems with a mass ratio of q ∼ 0.26 and a degree of contact factor f ∼ 32%. The primary component is hotter than the secondary by 95 K, this suggests us that the system is under thermal contact. The high orbital inclination (i = 82°.2) implies that VSX J0457 is a total eclipsing binary system and the photometric parameters here obtained are quite reliable. The absolute physical parameters of the two components in VSX J0457 are estimated. Based on these estimated parameters the evolutionary state of the system components is investigated and discussed. Combining our photometric solution with the 3-D correlation obtained for contact binaries by Gazeas (2009) we derive the masses and radii of the components of this eclipsing system as M1 = 1.44M⊙, M2 = 0.38M⊙, R1 = 1.55R⊙ and R2 = 0.87R⊙. The distance to VSX J0457 was calculated as 147 pc from this analysis, taking into account interstellar extinction.

Exploring the crowded central region of ten Galactic globular clusters using EMCCDs. Variable star searches and new discoveries

NASA Astrophysics Data System (ADS)

Figuera Jaimes, R.; Bramich, D. M.; Skottfelt, J.; Kains, N.; Jørgensen, U. G.; Horne, K.; Dominik, M.; Alsubai, K. A.; Bozza, V.; Calchi Novati, S.; Ciceri, S.; D'Ago, G.; Galianni, P.; Gu, S.-H.; Harpsøe, K. B. W.; Haugbølle, T.; Hinse, T. C.; Hundertmark, M.; Juncher, D.; Korhonen, H.; Mancini, L.; Popovas, A.; Rabus, M.; Rahvar, S.; Scarpetta, G.; Schmidt, R. W.; Snodgrass, C.; Southworth, J.; Starkey, D.; Street, R. A.; Surdej, J.; Wang, X.-B.; Wertz, O.

2016-04-01

Aims: We aim to obtain time-series photometry of the very crowded central regions of Galactic globular clusters; to obtain better angular resolution thanhas been previously achieved with conventional CCDs on ground-based telescopes; and to complete, or improve, the census of the variable star population in those stellar systems. Methods: Images were taken using the Danish 1.54-m Telescope at the ESO observatory at La Silla in Chile. The telescope was equipped with an electron-multiplying CCD, and the short-exposure-time images obtained (ten images per second) were stacked using the shift-and-add technique to produce the normal-exposure-time images (minutes). Photometry was performed via difference image analysis. Automatic detection of variable stars in the field was attempted. Results: The light curves of 12 541 stars in the cores of ten globular clusters were statistically analysed to automatically extract the variable stars. We obtained light curves for 31 previously known variable stars (3 long-period irregular, 2 semi-regular, 20 RR Lyrae, 1 SX Phoenicis, 3 cataclysmic variables, 1 W Ursae Majoris-type and 1 unclassified) and we discovered 30 new variables (16 long-period irregular, 7 semi-regular, 4 RR Lyrae, 1 SX Phoenicis and 2 unclassified). Fluxes and photometric measurements for these stars are available in electronic form through the Strasbourg astronomical Data Center. Based on data collected by the MiNDSTEp team with the Danish 1.54m telescope at ESO's La Silla observatory in Chile.Full Table 1 is only available at CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/588/A128

A Transparently-Scalable Metadata Service for the Ursa Minor Storage System

DTIC Science & Technology

2010-06-25

provide application-level guarantees. For example, many document editing programs imple- ment atomic updates by writing the new document ver- sion into a...Transparently-Scalable Metadata Service for the Ursa Minor Storage System 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...operations that could involve multiple servers, how close existing systems come to transparent scala - bility, how systems that handle multi-server

Realizing Autonomy via Intelligent Hybrid Control: Adaptable Autonomy for Achieving UxV RSTA Team Decision Superiority (also known as Intelligent Multi-UxV Planner with Adaptive Collaborative/Control Technologies (IMPACT))

DTIC Science & Technology

2018-01-30

algorithms. Due to this, Fusion was built with the goal of extensibility throughout the architecture. The Fusion infrastructure enables software...DISTRIBUTION STATEMENT A: Approved for public release. Cleared, 88PA, Case# 2018-0820. b. Trigger a Highly Mobile ...modes were developed in IMPACT (i.e., normal full coverage patrol (NFCP) and highly mobile (HM)). In both NFCP and HM, all UxVs patrol their assigned

User Experience Evaluations in Rehabilitation Video Games for Children: A Systematic Mapping of the Literature.

PubMed

Rico-Olarte, Carolina; López, Diego M; Blobel, Bernd; Kepplinger, Sara

2017-01-01

In recent years, the interest in user experience (UX) evaluation methods for assessing technology solutions, especially in health systems for children with special needs like cognitive disabilities, has increased. Conduct a systematic mapping study to provide an overview in the field of UX evaluations in rehabilitation video games for children. The definition of research questions, the search for primary studies and the extraction of those studies by inclusion and exclusion criteria lead to the mapping of primary papers according to a classification scheme. Main findings from this study include the detection of the target population of the selected studies, the recognition of two different ways of evaluating UX: (i) user evaluation and (ii) system evaluation, and UX measurements and devices used. This systematic mapping specifies the research gaps identified for future research works in the area.

Ultraviolet studies of nova-like variables with the IUE

NASA Technical Reports Server (NTRS)

Guinan, E. F.

1983-01-01

KQ Mon is a new UX UMa-type nova-like variable. Optical spectra taken in 1978 reveal very shallow Balmer absorption lines and He I (wavelength 4471) absorption. There was no evidence of orbital variations but the appearance of the optical spectrum and the presence of low amplitude flickering suggested a strong similarity to CD-42 degrees 14462 (=V3885 Sgr) and other members of the UX UMa class. KQ Mon was observed at low dispersion with the IUE satellite. Six spectra taken with the short wavelength prime (SWP) camera are dominated by strong broad absorption lines due to N V, O I, Si III, Si IV, C IV, He II, N IV, and A1 III. There is little evidence of orbital phase modulation over the time baseline of the observations. Unlike UV observations of other UX UMa-type objects, KQ Mon exhibits no emission lines or P Cygni-type profiles and the velocity displacements appear to be smaller, suggesting the absence of a hot, high velocity wind characterizing other UX UMa stars. The relationship of KQ Mon to other UX UMa disk stars is discussed and a model is suggested to explain their observed properties and the lack of major outbursts.

The general symmetry algebra structure of the underdetermined equation ux=(vxx)2

NASA Astrophysics Data System (ADS)

Kersten, Paul H. M.

1991-08-01

In a recent paper, Anderson, Kamran, and Olver [``Interior, exterior, and generalized symmetries,'' preprint (1990)] obtained the first- and second-order generalized symmetry algebra for the system ux=(vxx)2, leading to the noncompact real form of the exceptional Lie algebra G2. Here, the structure of the general higher-order symmetry algebra is obtained. Moreover, the Lie algebra G2 is obtained as ordinary symmetry algebra of the associated first-order system. The general symmetry algebra for ux=f(u,v,vx,...,) is established also.

FUSE Observations of the Bright, Eclipsing Nova-like Cataclysmic Variable, UX UMa (FUSE 2000)

NASA Technical Reports Server (NTRS)

Long, Knox; Froning, Cynthia

2004-01-01

This was a project to study the disk and wind of the eclipsing nova-like variable UX UMa, in order to better define the wind geometry of the system, including the nature of the transition region between the disk photosphere and the supersonic wind. We proposed to use phase resolved spectroscopy of the system, taking advantage of the fact that UX UMa is an eclipsing system, to isolate different regions of the wind and to use a Monte Carlo radiative transfer code to simulate the spectra through the eclipse.

Correlation between protein expression of FOXP3 and level of FOXP3 promoter methylation in recurrent spontaneous abortion.

PubMed

Hou, Wenhui; Li, Zhuyu; Li, Yinguang; Fang, Liyuan; Li, Jie; Huang, Jia; Li, Xiaoqing; You, Zeshan

2016-11-01

The aim of this study was to investigate the level of Forkhead box P3 (FOXP3) promoter methylation and protein expression in recurrent spontaneous abortion and to elucidate the pathogenesis of unexplained recurrent spontaneous abortion (URSA). We assessed a total of 56 URSA patients with a normal embryo, 24 recurrent spontaneous abortion (RSA) patients with an abnormal embryo (as control group 1), and 39 normal pregnant women (as control group 2). The expression of FOXP3 protein in deciduas was assessed through Western blot, and the level of FOXP3 promoter methylation was detected using bisulfite-assisted genomic sequencing polymerase chain reaction. The expressing quantity of FOXP3 protein in the URSA group was significantly lower than that in control groups 1 and 2, both with a P-value < 0.05. By contrast, no statistical difference was observed in the expressing quantity of FOXP3 protein of the two control groups (P = 0.212). The FOXP3 promoter methylation level in the URSA group was significantly higher than that in the two control groups, both of which exhibited a statistical difference of P-values < 0.05. Meanwhile, no statistical difference was observed in the FOXP3 promoter methylation level of the two control groups (P = 0.141). A negative correlation was found between the FOXP3 promoter methylation level and the expressing quantity of FOXP3 protein (r = -0.861, P < 0.05). Increasing FOXP3 promoter methylation levels may cause abnormal immune tolerance through the downregulation expression of the FOXP3 protein, which in turn leads to URSA. © 2016 The Authors. Journal of Obstetrics and Gynaecology Research published by John Wiley & Sons Australia, Ltd on behalf of Japan Society of Obstetrics and Gynecology.

UX Tau A Artist Concept

NASA Image and Video Library

2007-11-28

This artist concept is of the one-million-year-old star system called UX Tau A, approximately 450 light-years away. NASA Spitzer Space Telescope showed a gap in the dusty planet-forming disk swirling around the system central sun-like star.

Towards an Open, Distributed Software Architecture for UxS Operations

NASA Technical Reports Server (NTRS)

Cross, Charles D.; Motter, Mark A.; Neilan, James H.; Qualls, Garry D.; Rothhaar, Paul M.; Tran, Loc; Trujillo, Anna C.; Allen, B. Danette

2015-01-01

To address the growing need to evaluate, test, and certify an ever expanding ecosystem of UxS platforms in preparation of cultural integration, NASA Langley Research Center's Autonomy Incubator (AI) has taken on the challenge of developing a software framework in which UxS platforms developed by third parties can be integrated into a single system which provides evaluation and testing, mission planning and operation, and out-of-the-box autonomy and data fusion capabilities. This software framework, named AEON (Autonomous Entity Operations Network), has two main goals. The first goal is the development of a cross-platform, extensible, onboard software system that provides autonomy at the mission execution and course-planning level, a highly configurable data fusion framework sensitive to the platform's available sensor hardware, and plug-and-play compatibility with a wide array of computer systems, sensors, software, and controls hardware. The second goal is the development of a ground control system that acts as a test-bed for integration of the proposed heterogeneous fleet, and allows for complex mission planning, tracking, and debugging capabilities. The ground control system should also be highly extensible and allow plug-and-play interoperability with third party software systems. In order to achieve these goals, this paper proposes an open, distributed software architecture which utilizes at its core the Data Distribution Service (DDS) standards, established by the Object Management Group (OMG), for inter-process communication and data flow. The design decisions proposed herein leverage the advantages of existing robotics software architectures and the DDS standards to develop software that is scalable, high-performance, fault tolerant, modular, and readily interoperable with external platforms and software.

Chemical tagging of the Ursa Major moving group. A northern selection of FGK stars

NASA Astrophysics Data System (ADS)

Tabernero, H. M.; Montes, D.; González Hernández, J. I.; Ammler-von Eiff, M.

2017-01-01

Context. Stellar kinematic groups are kinematically coherent groups of stars that might have a common origin. These groups spread through the Galaxy over time owing to tidal effects caused by Galactic rotation and disk heating. However, the chemical information survives these processes. Aims: The information provided by analysis of chemical elements can reveal the origin of these kinematic groups. Here we investigate the origin of the stars that belong to the Ursa Major (UMa) moving group (MG). Methods: We present high-resolution spectroscopic observations obtained from three different spectrographs of kinematically selected FGK stars of the Ursa Major moving group. Stellar atmospheric parameters (Teff, log g, ξ, and [Fe/H]) were determined using our own automatic code (StePar), which makes use of the sensitivity of iron equivalent widths (EWs) measured in the spectra. We critically compared the StePar results with other methods (Teff values derived using the infrared flux method (IRFM) and log g values based on Hipparcos parallaxes). We derived the chemical abundances of 20 elements and their [X/Fe] ratios for all stars in the sample. We performed a differential abundance analysis with respect to a reference star of the UMa MG (HD 115043). We also carried out a systematic comparison of the abundance pattern of the Ursa Major MG and the Hyades SC with the thin disk stellar abundances. Results: Our chemical tagging analysis indicates that the Ursa Major MG is less affected by field star contamination than other moving groups (such as the Hyades SC). We find a roughly solar iron composition [Fe/H] = 0.03 ± 0.07 dex for the finally selected stars, whereas the [X/Fe] ratios are roughly subsolar except for super-solar Barium abundance. Conclusions: We conclude that 29 out of 44 (I.e., 66%) candidate stars have similar chemical compositions. In addition, we find that the abundance pattern of the Ursa Major MG might be marginally different from that of the Hyades SC. Based on observations obtained with the HERMES spectrograph at the Observatorio del Roque de los Muchachos (La Palma), the FOCES spectrograph at Calar Alto, and with the Coudé-Échelle spectrograph of the Alfred-Jensch-Teleskop at the Thüringer Landessternwarte Tautenburg.The reduced spectra (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/597/A33

Electronic and Magnetic Structures, Magnetic Hyperfine Fields and Electric Field Gradients in UX3 (X = In, Tl, Pb) Intermetallic Compounds

NASA Astrophysics Data System (ADS)

Khan, Sajid; Yazdani-Kachoei, Majid; Jalali-Asadabadi, Saeid; Farooq, Muhammad Bilal; Ahmad, Iftikhar

2018-02-01

Cubic uranium compounds such as UX3 (X is a non-transition element of groups IIIA or IVA) exhibit highly diverse magnetic properties, including Pauli paramagnetism, spin fluctuation and anti-ferromagnetism. In the present paper, we explore the structural, electronic and magnetic properties as well as the hyperfine fields (HFFs) and electric field gradients (EFGs) with quadrupole coupling constant of UX3 (X = In, Tl, Pb) compounds using local density approximation, Perdew-Burke-Ernzerhof parametrization of generalized gradient approximation (PBE-GGA) including the Hubbard U parameter (GGA + U), a revised version of PBE-GGA that improves equilibrium properties of densely packed solids and their surfaces (PBEsol-GGA), and a hybrid functional (HF-PBEsol). The spin orbit-coupling calculations have been added to investigate the relativistic effect of electrons in these materials. The comparison between the experimental parameters and our calculated structural parameters we confirm the consistency and effectiveness of our theoretical tools. The computed magnetic moments show that magnetic moment increases from indium to lead in the UX3 family, and all these compounds are antiferromagnetic in nature. The EFGs and HFFs, as well as the quadrupole coupling constant of UX3 (X = In, Tl, Pb), are discussed in detail. These properties primarily originate from f and p states of uranium and post-transition sites.

Pore Water Chemistry as Sensitive Indicators for Fluid Flow in Brazos-Trinity Basin #4 and Ursa Basin, Northeast Gulf of Mexico (IODP Expedition 308)

NASA Astrophysics Data System (ADS)

Jiang, S.; Gilhooly, W.; Takano, Y.; Flemings, P.; Behrmann, J.; John, C.

2005-12-01

Rapid sediment loading drives overpressure in marine sedimentary basins around the world. During IODP Expedition 308, two basins (Brazos-Trinity Basin #4 and Ursa Basin) with large different sedimentary loading of turbidite and hemipelagic sediments in the northeast Gulf of Mexico, were investigated to characterize in-situ spatial variations in temperature, pressure, and rock and fluid physical properties and chemistry. Pore water chemical compositions including alkalinity, salinity, pH, anions (Cl, SO4, PO4, H4SiO4), cations (Na, K, Ca, Mg), trace metals (Li, B, Sr, Ba, Fe, Mn), were analyzed in four drill holes at sites U1319, U1320, U1322, and U1324, in the Brazos-Trinity Basin #4 and Ursa Basin. At all sites, pore water chemistry shows great variability at shallow depths with maximam or miminum values corresponding well to seismic reflectors and lithostratigraphic units. The sulfate profile shows a dramatic decrease in SO4 content with a sulfate-methane interface (SMI) of 15 mbsf at Site 1319 and 22 mbsf at Site 1320 in the Brazos-Trinity Basin #4 Basin. In contrast, the sulfate- methane interfaces (SMI) are much deeper in Ursa Basin, i.e., 74 mbsf at Site 1322, and 94 mbsf at Site 2324. The deep SMI in Ursa Basin suggest relatively slow anaerobic degradation of organic matter considering the location of drilling site though we do not determine sulfate reducing rate with organic matter or methane as substrate at this leg. The downhole consumption of sulfate coincides with a concomitant increase in alkalinity and a decrease of Mn, Ca, Mg, Sr, and Li. Furthermore, initial pore water chemistry results appear to be influence by hydrogeologic fluid flow in both basins. Coincidence between pore water profile concentration maxima and parallel seismic reflectors may suggest that these seismic surfaces occur along specific stratigraphic units, which serve as channels for lateral fluid flow. Overall, the downhole variations in interstitial water chemistry may reflect a combination of processes, including anaerobic degradation of organic matter, diagenetic carbonate precipitation/dissolution, and fluid flow pathways.

The User Experience

ERIC Educational Resources Information Center

Schmidt, Aaron

2010-01-01

User experience (UX) is about arranging the elements of a product or service to optimize how people will interact with it. In this article, the author talks about the importance of user experience and discusses the design of user experiences in libraries. He first looks at what UX is. Then he describes three kinds of user experience design: (1)…

High-Resolution Near-Infrared Polarimetry of a Circumstellar Disk around UX Tau A

NASA Technical Reports Server (NTRS)

Serabyn, G.; Grady, C. A.; Currie, T.

2012-01-01

We present H-band polarimetric imagery of UX Tau A taken with HiCIAO/AO188 on the Subaru Telescope. UX Tau A has been classified as a pre-transitional disk object, with a gap structure separating its inner and outer disks. Our imagery taken with the 0.15" (21 AU) radius coronagraphic mask has revealed a strongly polarized circumstellar disk surrounding UX Tau A which extends to 120 AU, at a spatial resolution of 0.1" (14 AU). It is inclined by 46 degrees plus or minus 2 degrees as the west side is nearest. Although SED modeling and sub-millimeter imagery suggested the presence of a gap in the disk, with the inner edge of the outer disk estimated to be located at 25 - 30 AU, we detect no evidence of a gap at the limit of our inner working angle (23AU) at the near-infrared wavelength. We attribute the observed strong polarization (up to 66 %) to light scattering by dust grains in the disk. However, neither polarization models of the circumstellar disk based on Rayleigh scattering nor Mie scattering approximations were consistent with the observed azimuthal profile of the polarization degrees of the disk. Instead, a geometric optics model of the disk with nonspherical grains with the radii of 30 micrometers is consistent with the observed profile. We suggest that the dust grains have experienced frequent collisional coagulations and have grown in the circumstellar disk of UX Tau A.

Optical flare events on the RS Canum Venaticorum star UX Arietis

NASA Astrophysics Data System (ADS)

Cao, Dong-Tao; Gu, Sheng-Hong

2017-05-01

Based on long-term high-resolution spectroscopic observations obtained during five observing runs from 2001 to 2004, we study optical flare events and chromospheric activity variability of the very active RS CVn star UX Ari. By means of the spectral subtraction technique, several optical chromospheric activity indicators (including the He i D3, Na i D1, D2 doublet, Hα and Ca ii IRT lines) covered in our echelle spectra were analyzed. Four large optical flare events were detected on UX Ari during our observations, which show prominent He i D3 line emission together with great enhancement in emission of the Hα and Ca ii IRT lines and strong filled-in or emission reversal features in the Na i D1, D2 doublet lines. The newly detected flares are much more energetic than previous discoveries, especially for the flare identified during the 2002 December observing run. Optical flare events on UX Ari are more likely to be observed around two quadratures of the system, except for our optical flares detected during the 2004 November observing run. Moreover, we have found rotational modulation of chromospheric activity in the Hα and Ca ii IRT lines, which suggests the presence of chromospherically active longitudes over the surface of UX Ari. The change in chromospherically active longitudes among our observing runs, as well as the variation in chromospheric activity level from 2001 to 2004, indicates a long-term evolution of active regions.

High-Resolution Near-Infrared Polarimetry of a Circumstellar Disk around UX Tau A

NASA Astrophysics Data System (ADS)

Tanii, Ryoko; Itoh, Yoichi; Kudo, Tomoyuki; Hioki, Tomonori; Oasa, Yumiko; Gupta, Ranjan; Sen, Asoke K.; Wisniewski, John P.; Muto, Takayuki; Grady, Carol A.; Hashimoto, Jun; Fukagawa, Misato; Mayama, Satoshi; Hornbeck, Jeremy; Sitko, Michael L.; Russell, Ray W.; Werren, Chelsea; Curé, Michel; Currie, Thayne; Ohashi, Nagayoshi; Okamoto, Yoshiko; Momose, Munetake; Honda, Mitsuhiko; Inutsuka, Shu-ichi; Takeuchi, Taku; Dong, Ruobing; Abe, Lyu; Brandner, Wolfgang; Brandt, Timothy D.; Carson, Joseph; Egner, Sebastian E.; Feldt, Markus; Fukue, Tsubasa; Goto, Miwa; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko S.; Henning, Thomas; Hodapp, Klaus W.; Ishii, Miki; Iye, Masanori; Janson, Markus; Kandori, Ryo; Knapp, Gillian R.; Kusakabe, Nobuhiko; Kuzuhara, Masayuki; Matsuo, Taro; McElwain, Michael W.; Miyama, Shoken; Morino, Jun-ichi; Moro-Martín, Amaya; Nishimura, Tetsuro; Pyo, Tae-Soo; Serabyn, Eugene; Suto, Hiroshi; Suzuki, Ryuji; Takami, Michihiro; Takato, Naruhisa; Terada, Hiroshi; Thalmann, Christian; Tomono, Daigo; Turner, Edwin L.; Watanabe, Makoto; Yamada, Toru; Takami, Hideki; Usuda, Tomonori; Tamura, Motohide

2012-12-01

We present H-band polarimetric imagery of UX Tau A taken with HiCIAO/AO188 on the Subaru Telescope. UX Tau A has been classified as a pre-transitional disk object, with a gap structure separating its inner and outer disks. Our imagery taken with the 0.''15 (21 AU) radius coronagraphic mask has revealed a strongly polarized circumstellar disk surrounding UX Tau A, which extends to 120 AU, at a spatial resolution of 0.''1 (14 AU). It is inclined by 46° ± 2°, since the west side is nearest. Although SED modeling and sub-millimeter imagery have suggested the presence of a gap in the disk, with the inner edge of the outer disk estimated to be located at 25-30 AU, we detect no evidence of a gap at the limit of our inner working angle (23 AU) at the near-infrared wavelength. We attribute the observed strong polarization (up to 66%) to light scattering by dust grains in the disk. However, neither polarization models of the circumstellar disk based on Rayleigh-scattering nor Mie-scattering approximations were consistent with the observed azimuthal profile of the polarization degrees of the disk. Instead, a geometric optics model of the disk with nonspherical grains with radii of 30μm is consistent with the observed profile. We suggest that the dust grains have experienced frequent collisional coagulations, and have grown in the circumstellar disk of UX Tau A.

Resolving the inner disk of UX Orionis

NASA Astrophysics Data System (ADS)

Kreplin, A.; Madlener, D.; Chen, L.; Weigelt, G.; Kraus, S.; Grinin, V.; Tambovtseva, L.; Kishimoto, M.

2016-05-01

Aims: The cause of the UX Ori variability in some Herbig Ae/Be stars is still a matter of debate. Detailed studies of the circumstellar environment of UX Ori objects (UXORs) are required to test the hypothesis that the observed drop in photometry might be related to obscuration events. Methods: Using near- and mid-infrared interferometric AMBER and MIDI observations, we resolved the inner circumstellar disk region around UX Ori. Results: We fitted the K-, H-, and N-band visibilities and the spectral energy distribution (SED) of UX Ori with geometric and parametric disk models. The best-fit K-band geometric model consists of an inclined ring and a halo component. We obtained a ring-fit radius of 0.45 ± 0.07 AU (at a distance of 460 pc), an inclination of 55.6 ± 2.4°, a position angle of the system axis of 127.5 ± 24.5°, and a flux contribution of the over-resolved halo component to the total near-infrared excess of 16.8 ± 4.1%. The best-fit N-band model consists of an elongated Gaussian with a HWHM ~ 5 AU of the semi-major axis and an axis ration of a/b ~ 3.4 (corresponding to an inclination of ~72°). With a parametric disk model, we fitted all near- and mid-infrared visibilities and the SED simultaneously. The model disk starts at an inner radius of 0.46 ± 0.06 AU with an inner rim temperature of 1498 ± 70 K. The disk is seen under an nearly edge-on inclination of 70 ± 5°. This supports any theories that require high-inclination angles to explain obscuration events in the line of sight to the observer, for example, in UX Ori objects where orbiting dust clouds in the disk or disk atmosphere can obscure the central star. Based on observations made with ESO telescopes at Paranal Observatory under program IDs: 090.C-0769, 074.C-0552.

Dwarf novae

NASA Technical Reports Server (NTRS)

Ladous, Constanze

1993-01-01

Dwarf novae are defined on grounds of their semi-regular brightness variations of some two to five magnitudes on time scales of typically 10 to 100 days. Historically several different classification schemes have been used. Today, dwarf novae are divided into three sub-classes: the U Geminorum stars, the SU Ursae Majoris stars, and the Z Camelopardalis stars. Outbursts of dwarf novae occur at semi-periodic intervals of time, typically every 10 to 100 days; amplitudes range from typically 2 to 5 mag. Within certain limits values are characteristic for each object. Relations between the outburst amplitude, or the total energy released during outburst, and the recurrence time have been found, as well as relations between the orbital period and the outburst decay time, the absolute magnitude during outburst maximum, and the widths of long and short outbursts, respectively. Some dwarf novae are known to have suspended their normal outburst activity altogether for a while. They later resumed it without having undergone any observable changes. The optical colors of dwarf novae all are quite similar during outburst, considerably bluer than during the quiescent state. During the outburst cycle, characteristic loops in the two color diagram are performed. At a time resolution on the order of minutes, strictly periodic photometric changes due to orbital motion become visible in the light curves of dwarf novae. These are characteristic for each system. Remarkably little is known about orbital variations during the course of an outburst. On time-scales of minutes and seconds, further more or less periodic types of variability are seen in dwarf novae. Appreciable flux is emitted by dwarf novae at all wavelengths from the X-rays to the longest IR wavelengths, and in some cases even in the radio. Most dwarf novae exhibit strong emission line spectra in the optical and UV during quiescence, although some have only very weak emissions in the optical and/or weak absorptions at UV wavelengths.

Plant Diversity in Live Fences and Pastures, Two Examples from the Mexican Humid Tropics

NASA Astrophysics Data System (ADS)

Ruiz-Guerra, Betsabé; Rosas, Noé Velázquez; López-Acosta, Juan Carlos

2014-09-01

This study analyzes the potential uses of live fences and pastures as reservoirs of plant diversity for two regions with different management histories, Los Tuxtlas (LT) and Uxpanapa (UX), Veracruz, México. We studied two habitats, live fences and pastures, analyzed their species richness, diversity, structure and plant composition and classified species according to plant regeneration modes (light-demanding and shade tolerant), seed dispersal syndrome and their local uses. We recorded 62 species of trees at LT and 48 at UX. Live fences were more diverse than pastures in both regions. The LT site showed to analyze the relationship a higher diversity of plants in regeneration stages than the one at UX. However, UX had higher diversity of adult plants in the pastures than LT. Composition and structure of live fences were different between regions, as well as within live fences and pastures, 53 % of species were light-demanding and 40 % were shade tolerant; 70 % of the species were dispersed by birds. Differences between sites are associated with the modifications in live fences structure, which changed according to managerial practices and the use of local species; this may influence plant regeneration modes as well as the visits of avian dispersal agents. In LT, all species found in live fences were useful to humans, whereas in UX, less than half were used by the local population. Our results underline the importance of live fences and isolated trees in pasture habitats as potential sites to host native and useful species from tropical rain forests in livestock landscapes.

Overpressure, Low Effective Stress, and Slope Failure in the Ursa Region, Deep-Water Gulf of Mexico

NASA Astrophysics Data System (ADS)

Sawyer, D. E.; Flemings, P. B.

2004-12-01

Slope failures are associated with overpressured pore fluids and low effective stresses in the Quaternary strata of the Ursa Region, deep-water Gulf of Mexico. At Ursa, a permeable turbidite sandstone (the Blue Unit) is overlain by a low-permeability mudstone. Overpressure in the mudstone, measured with a pore pressure penetrometer (piezoprobe), begin within a few meters of the seafloor and extend 250-450 meters down to the Blue Unit. The overpressure ratio (λ *=(Pp-Phydrostatic)\\ (Sv-Phydrostatic), where Sv is the overburden stress, Pp is pore pressure, and Phydrostatic is the hydrostatic pressure) ranges from 0.8 where the overburden is thin to 0.4 where the overburden is thick. Detachment surfaces, mapped with high resolution 3D seismic data, are associated with zones where effective stresses are low. Four subsurface slumps were mapped and are oriented generally northwest-southeast. Slump surface areas are less than 250 km2 and maximum scarp-wall height on the largest slide is ˜120 meters. We interpret that asymmetric loading of the Blue Unit by low-permeable mudstone has driven fluids to where overburden is thin, decreased effective stress, and generated slope instability.

Clinical Efficacy of Low Molecular Heparin on Unexplained Recurrent Spontaneous Abortion.

PubMed

Xu, Guang-Li; Hu, Xiao-Fang; Han, Yong-Mei; Wei, Ai-Wu

2018-06-01

To study the clinical effect of low molecular heparin on unexplained recurrent spontaneous abortion (URSA). A total of 120 URSA patients were collected in our hospital from October 2015 to September 2017. They were divided into two groups: control group (n = 60) and observation group (n = 60). The patients in the control group were administered with progesterone and human chorionic gonadotropin, and the observation group with low molecular heparin. Pregnancy outcomes, incidence of complications in pregnancy and adverse drug reactions were compared in the two groups. The pregnancy success rate of patients in the observation group (90.00%) is higher than that in the control group (68.33%) (p < 0.05). The incidence of complications in pregnancy in the observation group (90.00%) is lower than those in the control group (68.33%) (p < 0.05). The incidence of adverse drug reactions between the patients in the observation group (20.00%) and those in the control group (23.33%) showed no significant difference (p > 0.05). Low molecular heparin treatment can improve pregnancy success rate and reduce the incidence of complications in the URSA patients. Low molecular heparin is characterized by safety and reliability and has potential for application in clinic.

Designing Unmanned Systems with Greater Autonomy: Using a Federated, Partially Open Systems Architecture Approach

DTIC Science & Technology

2014-01-01

system UAV unmanned aircraft vehicle UCI User -Computer Interface UCS UAS control segment Abbreviations xxix UGS unmanned ground system UGV unmanned ...made substantial progress in the deployment of more capable sensors, unmanned aircraft systems (UAS), and other unmanned systems (UxS). Innovative...progress in fielding more, and more capable unmanned aircraft systems (UAS) to meet the needs of warfighters

Living with an autonomous spatiotemporal home heating system: Exploration of the user experiences (UX) through a longitudinal technology intervention-based mixed-methods approach.

PubMed

Kruusimagi, Martin; Sharples, Sarah; Robinson, Darren

2017-11-01

Rising energy demands place pressure on domestic energy consumption, but savings can be delivered through home automation and engaging users with their heating and energy behaviours. The aim of this paper is to explore user experiences (UX) of living with an automated heating system regarding experiences of control, understanding of the system, emerging thermal behaviours, and interactions with the system as this area is not sufficiently researched in the existing homes setting through extended deployment. We present a longitudinal deployment of a quasi-autonomous spatiotemporal home heating system in three homes. Users were provided with a smartphone control application linked to a self-learning heating algorithm. Rich qualitative and quantitative data presented here enabled a holistic exploration of UX. The paper's contribution focuses on highlighting key aspects of UX living with an automated heating systems including (i) adoption of the control interface into the social context, (ii) how users' vigilance in maintaining preferred conditions prevailed as a better indicator of system over-ride than gross deviation from thermal comfort, (iii) limited but motivated proactivity in system-initiated communications as best strategy for soliciting user feedback when inference fails, and (iv) two main motivations for interacting with the interface - managing irregularities when absent from the house and maintaining immediate comfort, latter compromising of a checking behaviour that can transit to a system state alteration behaviour depending on mismatches. We conclude by highlighting the complex socio-technical context in which thermal decisions are made in a situated action manner, and by calling for a more holistic, UX-focused approach in the design of automated home systems involving user experiences. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Rotation and activity among solar-type stars of the Ursa Major Group

NASA Technical Reports Server (NTRS)

Soderblom, David R.; Mayor, Michel

1993-01-01

We examine rotation and chromospheric activity among G and K dwarfs recently shown to be members of the Ursa Major Group (UMaG). Rotation periods for UMaG stars are smaller than for stars of the same colors in the Hyades, and by an amount corresponding to the Skumanich relation. Most UMaG stars have about the same level of Ca II and K emission, implying that they also have nearly uniform intrinsic rotation rates. That means that the diversity of rotation rates and levels of activity seen among solar-type stars in the Alpha Persei and Pleiades clusters has largely converged by the age of UMaG (0.3 Gyr).

2018 Ground Robotics Capabilities Conference and Exhibiton

DTIC Science & Technology

2018-04-11

Transportable Robot System (MTRS) Inc 1 Non -standard Equipment (approved) Explosive Ordnance Disposal Common Robotic System-Heavy (CRS-H) Inc 1 AROC: 3-Star...and engineering • AI risk mitigation methodologies and techniques are at best immature – E.g., V&V; Probabilistic software analytics; code level...controller to minimize potential UxS mishaps and unauthorized Command and Control (C2). • PSP-10 – Ensure that software systems which exhibit non

Defense Science Board Task Force Report: The Role of Autonomy in DoD Systems

DTIC Science & Technology

2012-07-01

ASD(R&E) and the Military Services should schedule periodic, on-site collaborations that bring together academia, government and not-for-profit labs...expressing UxV activities, increased problem solving, planning and scheduling capabilities to enable dynamic tasking of distributed UxVs and tools for...industrial, governmental and military. Manufacturing has long exploited planning for logistics and matching product demand to production schedules

Exploring organisational competences in Human Factors and UX project work: managing careers, project tactics and organisational strategy.

PubMed

Furniss, Dominic; Curzon, Paul; Blandford, Ann

2018-06-01

Organisational competence in Human Factors and UX (user experience) has not been looked at before despite its relevance to project success. We define organisational competence as the collective competence of the individuals, bringing together their complementary abilities to deliver an outcome that is typically more than the sum of its parts. Twenty-two UX and Human Factors practitioners were interviewed about their project work in two contrasting domains: web design and safety-critical systems to explore organisational competences. Through doing a FRAM analysis, 29 functions and 6 main areas of competences were identified: the central project process; the process of learning about the problem; maintaining and developing client relations; staff development; evolving practices; and the management of documentation for audit and quality control. These dynamic and situated competences form a web of interactions. Managing competences is essential for project success. Implications for managing careers, project tactics and organisational strategy are discussed. Practitioner Summary: Organisational competences impact how routine and non-routine project work is performed, but these have received little attention in the literature. Six key areas of competences in Human Factors and UX project work were identified from practitioner interviews. Managing combinations of adaptive competences is important for developing careers, project tactics and organisational strategies.

The Spotted Active Binary UX Arietis

NASA Astrophysics Data System (ADS)

Hummel, Christian

2018-04-01

UX Arietis is one of the most active members of the RS CVn class of binaries in which spin-up of a sub-giant/giant star by a close companion led to the creation of magnetic fields which in turn are responsible for the radio and X-ray flares of UX Ariestis as well as its photometric variability. We observed this binary with the MIRC beam combiner at the CHARA array and made images of a single large spot rotating in and out of view over a month in 2012. A precise orbit was derived using the Wilson-Devinney code to account for the effect of the spot on the measured visibilities. Archival and new radial velocities taken at the NOT were also corrected for spot activity and allowed us to determine precise stellar masses and luminosities for the components. Consistency with the predicted locations in the HR-diagram is achieved after a careful analysis of the effect of spots. The orbit can be used to establish the relative locations of the stellar components at times when radio observations by Ros and Massi (2007) with the VLBA detected two radio components moving around each other. We tentatively conclude that radio emission in UX Arietis flows along magnetic flux tubes between the stars.

The Chemical Signature of SNIax in the Stars of Ursa Minor?

NASA Astrophysics Data System (ADS)

Cescutti, Gabriele; Kobayashi, Chiaki

2018-06-01

Recently, a new class of supernovae Ia was discovered: the supernovae Iax; the increasing sample of these objects share common features as lower maximum-light velocities and typically lower peak magnitudes.In our scenario, the progenitors of the SNe Iax are very massive white dwarfs, possibly hybrid C+O+Ne white dwarfs; due to the accretion from a binary companion, they reach the Chandrasekhar mass and undergo a central carbon deflagration, but the deflagration is quenched when it reaches the outer O+Ne layer. This class of SNe Ia are expected to be rarer than standard SNe Ia and do not affect the chemical evolution in the solar neighbourhood; however, they have a short delay time and they could influence the evolution of metal-poor systems. Therefore, we have included in a stochastic chemical evolution model for the dwarf spheroidal galaxy Ursa minor the contribution of SNe Iax.The model predicts a spread in [Mn/Fe] in the ISM medium at low metallicity and - at the same time - a decrease of the [alpha/Fe] elements, as in the classical time delay model. This is in surprising agreement with the observed abundances in stars of Ursa minor and provide a strong indication to the origin of this new classes of SNIa.

On quasi-periodic solutions for generalized Boussinesq equation with quadratic nonlinearity

NASA Astrophysics Data System (ADS)

Shi, Yanling; Xu, Junxiang; Xu, Xindong

2015-02-01

In this paper, one-dimensional generalized Boussinesq equation: utt - uxx + (u2 + uxx)xx = 0 with boundary conditions ux(0, t) = ux(π, t) = uxxx(0, t) = uxxx(π, t) = 0 is considered. It is proved that the equation admits a Whitney smooth family of small-amplitude quasi-periodic solutions with 2-dimensional Diophantine frequencies. The proof is based on an infinite dimensional Kolmogorov-Arnold-Moser theorem and Birkhoff normal form.

Transportable Manned and Robotic Digital Geophysical Mapping Tow Vehicle, Phase 1

DTIC Science & Technology

2007-08-01

by using the UX PROCESS QC/QA tools to evaluate quality. Areas evaluated included induced noise, position and track accuracy, synchronization/latency... tools . To gain additional data on productivity and the effect of alternate direction of travel we mapped an unobstructed subset of the Grid 1-4 area...independently evaluated by using the UX PROCESS QC/QA tools to evaluate quality. Areas evaluated included induced noise, position and track

Copernicus observations of Ly-alpha and Mg II emission from HR 1099 /V711 Tauri/ and UX Ari

NASA Technical Reports Server (NTRS)

Weiler, E. J.

1978-01-01

Ultraviolet observations of two RS CVn binaries obtained with Copernicus are described. High-resolution (0.05 A) U1 observations indicate that both HR 1099 and UX Ari display broad Ly-alpha emission. The Ly-alpha emission strength from HR 1099 is variable and seems to be correlated with orbital phase, while the UX Ari results indicate no significant variation. Moderate resolution (0.51 A) V2 scans of both systems show variable Mg II h and k emission-line profiles which usually matched the velocity of the more active star in each binary. Additionally, displaced emission components were seen at velocities of up to + or - 250 km/s, indicative of high-velocity gas motions. The radial velocities of these emission features from HR 1099 are marginally correlated with orbital phase. Highly active and variable chromospheric phenomena are found to be the most consistent explanation of these results.

X-ray and radio observations of flares from the RS Canum Venaticorum system UX ARIETIS

NASA Astrophysics Data System (ADS)

Tsuru, T.; Makishima, K.; Ohashi, T.; Inoue, H.; Koyama, K.; Turner, M. J. L.; Barstow, M. A.; McHardy, I. M.; Pye, J. P.; Tsunemi, H.; Kitamoto, S.; Taylor, A. R.; Nelson, R. F.

In July 1987 the RS CVn system UX Ari was observed in the 2-20-keV X-ray band by Ginga, immediately followed by 5-GHz radio observations. UX Ari was found to be very active at both radio and X-ray frequencies. Quiescent X-ray emission with a luminosity of 3 x 10 to the 31st erg/s (in the 2-20-keV band) was detected, together with two intense X-ray flares up to 2 x 10 to the 32nd and 6 x 10 to the 31st erg/s, respectively. Both flare and quiescent X-ray spectra are well fitted by single-temperature thermal bremsstrahlung models, with the continuum temperature and emission measure in the range 4-7 kev (in kT) and (2-10) x 10 to the 54th/cu cm, respectively.

Astrometry of the Red Supergiant Star VY Canis Majoris with VERA

NASA Astrophysics Data System (ADS)

Choi, Y. K.; Hirota, T.; Honma, M.; Kobayashi, H.

2009-08-01

We present observational results on the red supergiant VY Canis Majoris with VERA. We have observed 22 GHz H_2O masers and 43 GHz SiO masers (v=1 and 2 J=1-0) around VY CMa for 13 months. We successfully detected a parallax of 0.87 ± 0.08 mas, corresponding to 1.15 +0.10 -0.09 kpc of distance using H_2O masers. As results of phase--referencing analyses, we have measured absolute positions for both the H_2O masers and SiO masers. The proper motions of the H_2O masers show the tendency of expansion.

Astrometry of red supergiant VY Canis Majoris with VERA

NASA Astrophysics Data System (ADS)

Choi, Y. K.; Hirota, T.; Honma, M.; Kobayashi, H.

2008-07-01

We present observational results on the red supergiant VY Canis Majoris with VERA. We have observed 22 GHz H2O masers and 43 GHz SiO masers (v=1 and 2 J=1-0) around VY CMa for 13 months. We succesfully detected a parallax of 0.87 ± 0.08 mas, corresponding to the distance of 1.15 +0.10-0.09 kpc using H2O masers. As the result of phase-referencing analyses, we have measured absolute positions for both H2O masers and SiO masers. The H2O maser features show rapid expansion off the central star.

Complete 3D kinematics of upper extremity functional tasks.

PubMed

van Andel, Carolien J; Wolterbeek, Nienke; Doorenbosch, Caroline A M; Veeger, DirkJan H E J; Harlaar, Jaap

2008-01-01

Upper extremity (UX) movement analysis by means of 3D kinematics has the potential to become an important clinical evaluation method. However, no standardized protocol for clinical application has yet been developed, that includes the whole upper limb. Standardization problems include the lack of a single representative function, the wide range of motion of joints and the complexity of the anatomical structures. A useful protocol would focus on the functional status of the arm and particularly the orientation of the hand. The aim of this work was to develop a standardized measurement method for unconstrained movement analysis of the UX that includes hand orientation, for a set of functional tasks for the UX and obtain normative values. Ten healthy subjects performed four representative activities of daily living (ADL). In addition, six standard active range of motion (ROM) tasks were executed. Joint angles of the wrist, elbow, shoulder and scapula were analyzed throughout each ADL task and minimum/maximum angles were determined from the ROM tasks. Characteristic trajectories were found for the ADL tasks, standard deviations were generally small and ROM results were consistent with the literature. The results of this study could form the normative basis for the development of a 'UX analysis report' equivalent to the 'gait analysis report' and would allow for future comparisons with pediatric and/or pathologic movement patterns.

CRUSER (Consortium for Robotics and Unmanned Systems Education and Research)

DTIC Science & Technology

2013-07-08

LPI) comms: covert and innovative networks – such as the “Digital Semaphore ” concept being taken to field experimentation in FY13. 3)  UxS support of...Resolution Full Motion Video for Unmanned Systems and Remote Sensing Jeff Weekley, NPS Digital Semaphore Dr. Don Brutzman, NPS •  7-10 May 2012... Semaphore CRUSER  Thread  1   Sept  2011   Warfare   InnovaKon   Workshop   May  2012   Technical   ConKnuum   Apr  2013

Infrared observations of circumstellar ammonia in OH/IR supergiants

NASA Technical Reports Server (NTRS)

Mclaren, R. A.; Betz, A. L.

1980-01-01

Ammonia has been detected in the circumstellar envelopes of VY Canis Majoris, VX Sagittarii, and IRC +10420 by means of several absorption lines in the nu-2 vibration-rotation band near 950 kaysers. The line profiles are well resolved (0.2 km/sec resolution) and show the gas being accelerated to terminal expansion velocities near 30 km/sec. The observations reveal a method for determining the position of the central star on VLBI maps of OH maser emission to an accuracy of approximately 0.2 arcsec. A firm lower limit of 2 x 10 to the 15th/sq cm is obtained for the NH3 column density in VY Canis Majoris.

SDSS J162520.29+120308.7 - a new SU Ursae Majoris star in the period gap

NASA Astrophysics Data System (ADS)

Olech, A.; de Miguel, E.; Otulakowska, M.; Thorstensen, J. R.; Rutkowski, A.; Novak, R.; Masi, G.; Richmond, M.; Staels, B.; Lowther, S.; Stein, W.; Ak, T.; Boyd, D.; Koff, R.; Patterson, J.; Eker, Z.

2011-08-01

We report results of an extensive world-wide observing campaign devoted to the recently discovered dwarf nova SDSS J162520.29+120308.7 (SDSS J1625). The data were obtained during the July 2010 eruption of the star and in August and September 2010 when the object was in quiescence. During the July 2010 superoutburst, SDSS J1625 clearly displayed superhumps with a mean period of Psh = 0.095942(17) days (138.16 ± 0.02 min) and a maximum amplitude reaching almost 0.4 mag. The superhump period was not stable, decreasing very rapidly at a rate of Ṗ = -1.63(14) × 10-3 at the beginning of the superoutburst and increasing at a rate of Ṗ = 2.81(20) × 10-4 in the middle phase. At the end of the superoutburst, it stabilized around the value of Psh = 0.09531(5) day. During the first twelve hours of the superoutburst, a low-amplitude double wave modulation was observed whose properties are almost identical to early superhumps observed in WZ Sge stars. The period of early superhumps, the period of modulations observed temporarily in quiescence, and the period derived from radial velocity variations are the same within measurement errors, allowing us to estimate the most probable orbital period of the binary to be Porb = 0.09111(15) days (131.20 ± 0.22 min). This value clearly indicates that SDSS J1625 is another dwarf nova in the period gap. Knowledge of the orbital and superhump periods allows us to estimate the mass ratio of the system to be q ≈ 0.25. This high value poses serious problems for both the thermal and tidal instability (TTI) model describing the behaviour of dwarf novae and for some models explaining the origin of early superhumps. The reduced lightcurve data are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/532/A64

The cataclysmic variables from the Palomar-Green survey

NASA Astrophysics Data System (ADS)

Ringwald, F. A.

1993-09-01

This thesis explores the cataclysmic variables (CVs) found by the Palomar-Green (PG) survey. This is the first compilation of a statistically complete sample of CVs found by ultraviolet color excess, and not outburst behavior. Blue and red follow-up spectrophotometry suggests that 22 of 68 objects classified originally as CVs are hot subdwarfs. Cool companions may be mimicking CVs' flat energy distributions, although the possibility remains that some are face-on CVs. Spectra taken with the International Ultraviolet Explorer satellite prove useful for distinguishing difficult cases. With the CV sample defined, the orbital periods for eleven systems are investigated with radial velocity studies. At 16th magnitude, CV number counts increase by 2.3 mag-1, although this may level off. The luminosity function is examined for the first time, and a trend toward higher space density at low luminosity is suspected. Outburst properties are compiled, and low-luminosity dwarf novae inflate the total space density to 6 x 10-6 pc-3. I describe all the PG CVs and candidate objects, and show spectra for most. This sample should be useful for population studies, such as measuring the space density with trigonometric parallaxes, or finding the fraction of eclipsing CVs. A new class of nova-likes, the SW Sextantis stars, is characterized by absorption events of the emission lines at spectroscopic phase 0.5, accompanied by large phase lags between the lightcurves and the radial velocity curves and strong high-excitation emission. There are at least six such CVs in this sample of 33, so this mysterious behavior must be common and not peculiar, as previously thought. Five of these six objects eclipse. Serendipitous results for individual CVs include finding low-frequency quasi-periodic variations in the radial velocity curve of the dwarf nova BZ Ursae Majoris. While erratic from epoch to epoch, these are too coherent to be pure noise. Another dwarf nova, HX Pegasi, is caught with time-resolved spectrophotometry on the rise to outburst. This is the second-ever such observation, and the first with red spectra. HX Pegasi is also confirmed as having a novel subdwarf-K red star.

Sr-Nd isotopes constrain on the deposit history of the basins in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Li, Y.; Jiang, S.

2015-12-01

The Brazos-Trinity Basin IV and Ursa Basin are situated on the northern slope of the Gulf of Mexico. The Ursa basin lies in the center of late Pleistocene Mississippi River deposition, received the sediment deposition during Marine Isotope Stage (MIS) 2- 4. The Brazos-Trinity Basin IV belongs to a part of the Brazos-Trinity fan, it recorded the turbidite deposition and hemiplegic deposition during MIS1- 5. The Sr and Nd isotopic composition of the detrital composition of the sediment in both basins indicates the change of the sediment provenance during the basin-filled process. In the Ursa basin, The difference of 87Sr/86Sr ratio and ɛNd of the detrital component between MIS1,2 (87Sr/86Sr ~ 0.7219 - 0.7321, ɛNd ~ -12 - -13.4) and MIS3,4(87Sr/86Sr ~ 0.7310 - 0.7354, ɛNd ~ -16 - -17.9) is suggested to be related with the provenance change of the detrital particles since LGM. The addition of detrital particle from Appalachians with less radiogenic 87Sr/86Sr and positive ɛNd altered the character of the sediment of the Mississippi River during the last glaciation and deglaciation. In the Brazos-Trinity Basin IV, the narrow range of 87Sr/86Sr and ɛNd indicate that the sediment source of Brazos-Trinity Basin IV had not changed obviously during MIS5e to MIS2, mostly from coastal rivers such as Brazos River, Trinity River and Sabine River. The pre-fan with 87Sr/86Sr ~0.735 and ɛNd ~ -14.5 to -16.9, which is very similar to the deep sediment in the Ursa Basin with 87Sr/86Sr ~0.733 to 0.735 and ɛNd ~ -16 to -18. It is suggested that sediments of the pre-fan of the Brazos-Trinity Basin IV were supplied from the ancestral Mississippi River Delta during the low sea level (MIS 6). During the MIS5, the discharge of Mississippi River is thought switched to its present course, ~300 km to the east.

Conservation laws and symmetries of a generalized Kawahara equation

NASA Astrophysics Data System (ADS)

Gandarias, Maria Luz; Rosa, Maria; Recio, Elena; Anco, Stephen

2017-06-01

The generalized Kawahara equation ut = a(t)uxxxxx + b(t)uxxx + c(t) f (u)ux appears in many physical applications. A complete classification of low-order conservation laws and point symmetries is obtained for this equation, which includes as a special case the usual Kawahara equation ut = αuux + βu2ux + γuxxx + μuxxxxx. A general connection between conservation laws and symmetries for the generalized Kawahara equation is derived through the Hamiltonian structure of this equation and its relationship to Noether's theorem using a potential formulation.

Earthdata Search Usability Study Process

NASA Technical Reports Server (NTRS)

Reese, Mark

2016-01-01

User experience (UX) design is the process of enhancing user satisfaction by improving various aspects of the user's interaction with an application or website. One aspect of UX design is usability, or the extent to which an application can be used to to accomplish tasks efficiently, effectively, and with satisfaction. NASA's Earthdata Search Client recently underwent a focused usability testing project to measure usability and gain valuable user feedback and insights to increase usability for its end-users. This presentation focuses on the process by which the usability tests were administered and the lessons learned throughout the process.

Short-Wavelength Infrared Views of Messier 81

NASA Image and Video Library

2003-12-18

The magnificent spiral arms of the nearby galaxy Messier 81 are highlighted in this NASA Spitzer Space Telescope image. Located in the northern constellation of Ursa Major which also includes the Big Dipper.

Interferometric Observations of the SiO High J Transition Maser associated with VY Canis Majoris with the Submillimeter Array

NASA Astrophysics Data System (ADS)

Shinnaga, H.; Moran, J. M.; Young, K. H.; Ho, P. T. P.

2005-12-01

We imaged the SiO maser emission of J=5-4 in the v=1 state associated with the peculiar red supergiant VY Canis Majoris using the partially completed Submillimeter Array. We identified seven maser components and measured the relative positions at sub-arcsecond scale in the high J transition for the first time. We have also measured the polarization of these maser components. The strongest maser feature has a linear polarization of ˜ 60%, and its direction of polarization is approximately aligned with the bipolar axis. Such a high degree of polarization suggests that radiative pumping is probably responsible for the maser inversion. Five of the other maser features have significant linear polarization.

UX Tau A

NASA Technical Reports Server (NTRS)

2007-01-01

This is an artist's rendition of the one-million-year-old star system called UX Tau A, located approximately 450 light-years away. Observations from NASA's Spitzer Space Telescope showed a gap in the dusty planet-forming disk swirling around the system's central sun-like star.

Spitzer saw a gap in UX Tau A's disk that extends from 0.2 to 56 astronomical units (an astronomical unit is the distance between the sun and Earth). The gap extends from the equivalent of Mercury to Pluto in our solar system, and is sandwiched between thick inner and outer disks on either side. Astronomers suspect that the gap was carved out by one or more forming planets.

Such dusty disks are where planets are thought to be born. Dust grains clump together like snowballs to form larger rocks, and then the bigger rocks collide to form the cores of planets. When rocks revolve around their central star, they act like cosmic vacuum cleaners, picking up all the gas and dust in their path and creating gaps.

Although gaps have been detected in disks swirling around young stars before, UX Tau A is special because the gap is sandwiched between two thick disks of dust. An inner thick dusty disk hugs the central star, then, moving outward, there is a gap, followed by another thick doughnut-shaped disk. Other systems with gaps contain very little to no dust near the central star. In other words, those gaps are more like big holes in the centers of disks.

Some scientists suspect that these holes could have been carved out by a process called photoevaporation. Photoevaporation occurs when radiation from the central star heats up the gas and dust around it to the point where it evaporates away. The fact that there is thick disk swirling extremely close to UX Tau A's central star rules out the photoevaporation scenario. If photoevaporation from the star played a role, then large amounts of dust would not be floating so close to the star.

Binding pattern of intermediate UDP-4-keto-xylose to human UDP-xylose synthase: Synthesis and STD NMR of model keto-saccharides.

PubMed

Puchner, Claudia; Eixelsberger, Thomas; Nidetzky, Bernd; Brecker, Lothar

2017-01-02

Human UDP-xylose synthase (hUXS1) exclusively converts UDP-glucuronic acid to UDP-xylose via intermediate UDP-4-keto-xylose (UDP-Xyl-4O). Synthesis of model compounds like methyl-4-keto-xylose (Me-Xyl-4O) is reported to investigate the binding pattern thereof to hUXS1. Hence, selective oxidation of the desired hydroxyl function required employment of protecting group chemistry. Solution behavior of synthesized keto-saccharides was studied without enzyme via 1 H and 13 C NMR spectroscopy with respect to existent forms in deuterated potassium phosphate buffer. Keto-enol tautomerism was observed for all investigated keto-saccharides, while gem-diol hydrate forms were only observed for 4-keto-xylose derivatives. Saturation transfer difference (STD) NMR was used to study binding of synthesized keto-gylcosides to wild type hUXS1. Resulting epitope maps were correlated to earlier published molecular modeling studies of UDP-Xyl-4O. STD NMR results of Me-Xyl-4O are in good agreement with simulations of the intermediate UDP-Xyl-4O indicating a strong interaction of proton H3 with the enzyme, potentially caused by active site residue Ala 79 . In contrast, pyranoside binding pattern studies of methyl uronic acids showed some differences compared to previously published STD NMR results of UDP-glycosides. In general, obtained results can contribute to a better understanding in binding of UDP-glycosides to other UXS enzyme family members, which have high structural similarities in the active site. Copyright © 2016. Published by Elsevier Ltd.

Intelligent Agent Transparency in Human-Agent Teaming for Multi-UxV Management.

PubMed

Mercado, Joseph E; Rupp, Michael A; Chen, Jessie Y C; Barnes, Michael J; Barber, Daniel; Procci, Katelyn

2016-05-01

We investigated the effects of level of agent transparency on operator performance, trust, and workload in a context of human-agent teaming for multirobot management. Participants played the role of a heterogeneous unmanned vehicle (UxV) operator and were instructed to complete various missions by giving orders to UxVs through a computer interface. An intelligent agent (IA) assisted the participant by recommending two plans-a top recommendation and a secondary recommendation-for every mission. A within-subjects design with three levels of agent transparency was employed in the present experiment. There were eight missions in each of three experimental blocks, grouped by level of transparency. During each experimental block, the IA was incorrect three out of eight times due to external information (e.g., commander's intent and intelligence). Operator performance, trust, workload, and usability data were collected. Results indicate that operator performance, trust, and perceived usability increased as a function of transparency level. Subjective and objective workload data indicate that participants' workload did not increase as a function of transparency. Furthermore, response time did not increase as a function of transparency. Unlike previous research, which showed that increased transparency resulted in increased performance and trust calibration at the cost of greater workload and longer response time, our results support the benefits of transparency for performance effectiveness without additional costs. The current results will facilitate the implementation of IAs in military settings and will provide useful data to the design of heterogeneous UxV teams. © 2016, Human Factors and Ergonomics Society.

Science Notes.

ERIC Educational Resources Information Center

Talbot, Chris; And Others

1991-01-01

Twenty science experiments are presented. Topics include recombinant DNA, physiology, nucleophiles, reactivity series, molar volume of gases, spreadsheets in chemistry, hydrogen bonding, composite materials, radioactive decay, magnetism, speed, charged particles, compression waves, heat transfer, Ursa Major, balloons, current, and expansion of…

Galaxy in Different Lights

NASA Image and Video Library

2014-10-08

The comparison from NASA Hubble telescope and Chandra X-ray Observatory highlights how different the universe can look when viewed in other wavelengths of light. M82 is located 12 million light-years away in the Ursa Major constellation.

Large dust grains in the wind of VY Canis Majoris

NASA Astrophysics Data System (ADS)

Scicluna, P.; Siebenmorgen, R.; Wesson, R.; Blommaert, J. A. D. L.; Kasper, M.; Voshchinnikov, N. V.; Wolf, S.

2015-12-01

Massive stars live short lives, losing large amounts of mass through their stellar wind. Their mass is a key factor determining how and when they explode as supernovae, enriching the interstellar medium with heavy elements and dust. During the red supergiant phase, mass-loss rates increase prodigiously, but the driving mechanism has proven elusive. Here we present high-contrast optical polarimetric-imaging observations of the extreme red supergiant VY Canis Majoris and its clumpy, dusty, mass-loss envelope, using the new extreme-adaptive-optics instrument SPHERE at the VLT. These observations allow us to make the first direct and unambiguous detection of submicron dust grains in the ejecta; we derive an average grain radius ~0.5 μm, 50 times larger than in the diffuse ISM, large enough to receive significant radiation pressure by photon scattering. We find evidence for varying grain sizes throughout the ejecta, highlighting the dynamical nature of the envelope. Grains with 0.5 μm sizes are likely to reach a safe distance from the eventual explosion of VY Canis Majoris; hence it may inject upwards of 10-2 M⊙ of dust into the ISM. Based on observations made with European Southern Observatory (ESO) telescopes at the La Silla Paranal Observatory under program 60.A-9368(A).Appendix A is available in electronic form at http://www.aanda.org

Near-Earth and near-Mars asteroids: Prognosis of pyroxene types

NASA Technical Reports Server (NTRS)

Shestopalov, D. I.; Golubeva, L. F.

1991-01-01

The diagnostic signs of ferrous absorption band at 505nm and color index (u-x) found at main-belt asteroids and 6-parametric classification of light stone meteorites have been the basis of the work. The colorimetric data of light near-Earth and near-Mars asteroids from TRIAD and ECAS were analyzed. Composition fields of pyroxenes were obtained for these asteroids by the value of (u-x) and 505-nm ferrous absorption band position within the pyroxenes quadrilateral. Pyroxenes of the S-asteroids from Apollo-Amor which have spectral parameters similar to achondrites may be presented by the diopside series.

Designing an intuitive web application for drug discovery scientists.

PubMed

Karamanis, Nikiforos; Pignatelli, Miguel; Carvalho-Silva, Denise; Rowland, Francis; Cham, Jennifer A; Dunham, Ian

2018-06-01

We discuss how we designed the Open Targets Platform (www.targetvalidation.org), an intuitive application for bench scientists working in early drug discovery. To meet the needs of our users, we applied lean user experience (UX) design methods: we started engaging with users very early and carried out research, design and evaluation activities within an iterative development process. We also emphasize the collaborative nature of applying lean UX design, which we believe is a foundation for success in this and many other scientific projects. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Accuracy Investigation of Creating Orthophotomaps Based on Images Obtained by Applying Trimble-UX5 UAV

NASA Astrophysics Data System (ADS)

Hlotov, Volodymyr; Hunina, Alla; Siejka, Zbigniew

2017-06-01

The main purpose of this work is to confirm the possibility of making largescale orthophotomaps applying unmanned aerial vehicle (UAV) Trimble- UX5. A planned altitude reference of the studying territory was carried out before to the aerial surveying. The studying territory has been marked with distinctive checkpoints in the form of triangles (0.5 × 0.5 × 0.2 m). The checkpoints used to precise the accuracy of orthophotomap have been marked with similar triangles. To determine marked reference point coordinates and check-points method of GNSS in real-time kinematics (RTK) measuring has been applied. Projecting of aerial surveying has been done with the help of installed Trimble Access Aerial Imaging, having been used to run out the UX5. Aerial survey out of the Trimble UX5 UAV has been done with the help of the digital camera SONY NEX-5R from 200m and 300 m altitude. These aerial surveying data have been calculated applying special photogrammetric software Pix 4D. The orthophotomap of the surveying objects has been made with its help. To determine the precise accuracy of the got results of aerial surveying the checkpoint coordinates according to the orthophotomap have been set. The average square error has been calculated according to the set coordinates applying GNSS measurements. A-priori accuracy estimation of spatial coordinates of the studying territory using the aerial surveying data have been calculated: mx=0.11 m, my=0.15 m, mz=0.23 m in the village of Remeniv and mx=0.26 m, my=0.38 m, mz=0.43 m in the town of Vynnyky. The accuracy of determining checkpoint coordinates has been investigated using images obtained out of UAV and the average square error of the reference points. Based on comparative analysis of the got results of the accuracy estimation of the made orthophotomap it can be concluded that the value the average square error does not exceed a-priori accuracy estimation. The possibility of applying Trimble UX5 UAV for making large-scale orthophotomaps has been investigated. The aerial surveying output data using UAV can be applied for monitoring potentially dangerous for people objects, the state border controlling, checking out the plots of settlements. Thus, it is important to control the accuracy the got results. Having based on the done analysis and experimental researches it can be concluded that applying UAV gives the possibility to find data more efficiently in comparison with the land surveying methods. As the result, the Trimble UX5 UAV gives the possibility to survey built-up territories with the required accuracy for making orthophotomaps with the following scales 1: 2000, 1: 1000, 1: 500.

The Universe First Fireworks

NASA Image and Video Library

2006-12-18

This is an image from NASA Spitzer Space Telescope of stars and galaxies in the Ursa Major constellation. This infrared image covers a region of space so large that light would take up to 100 million years to travel across it.

Two new triterpene saponins from the anti-inflammatory saponin fraction of Ilex pubescens root.

PubMed

Wang, Jing-Rong; Zhou, Hua; Jiang, Zhi-Hong; Liu, Liang

2008-07-01

The saponin fraction from the ethanolic extracts of the root of Ilex pubescens Hook. et Arn. (Ilexaceae) was found to exhibit potent anti-inflammatory effects on carrageenan-induced paw edema in rats. Two novel triterpene saponins, pubescenosides C and D (1 and 2, resp.), together with five known saponins were isolated from this saponin fraction. The structures of 1 and 2 were elucidated as (20beta)-3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-xylopyranosyl]ursa-12,18-dien-28-oic acid 28-O-beta-D-glucopyranosyl ester, and (20beta)-3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-xylopyranosyl]ursa- 12,18-dien-28-oic acid 28-O-beta-D-glucopyranosyl ester, respectively, on the basis of chemical and spectroscopic data. Five known saponins isolated from the saponin fraction were identified as ilexsaponin B(1), B(2), B(3), A(1), and chikusetsusaponin IV(a).

Unveiling the molecular bipolar outflow of the peculiar red supergiant VY Canis Majoris

NASA Astrophysics Data System (ADS)

Shinnaga, Hiroko; Claussen, Mark J.; Lim, Jeremy; Dinh-van-Trung; Tsuboi, Masato

2003-04-01

We carried out polarimetric spectral-line imaging of the molecular outflow of the peculiar red supergiant VY Canis Majoris in SiO J=1-0 line in the ground vibrational state, which contains highly linearly-polarized velocity components, using the Very Large Array. We succeeded in unveiling the highly linearly polarized bipolar outflow for the first time at subarcsecond spatial resolution. The results clearly show that the direction of linear polarization of the brightest maser components is parallel to the outflow axis. The results strongly suggest that the linear polarization of the SiO maser is closely related to the outflow phenomena of the star. Furthermore, the results indicate that the linear polarization observed in the optical and infrared also occur due to the outflow phenomena.

557 GHz Observations of Water Vapor Outflow from VY Canis Majoris and W Hydrae

NASA Astrophysics Data System (ADS)

Harwit, Martin; Bergin, Edwin A.

2002-02-01

We report the first detection of thermal water vapor emission in the 557 GHz, 110-101 ground-state transition of ortho-H2O toward VY Canis Majoris. In observations obtained with the Submillimeter Wave Astronomy Satellite, we measured a flux of ~450 Jy, in a spectrally resolved line centered on a velocity vLSR=25 km s-1 with an FWHM of ~35 km s-1, somewhat dependent on the assumed line shape. We analyze the line shape in the context of three different radial outflow models for which we provide analytical expressions. We also detected a weaker 557 GHz emission line from W Hydrae. We find that these and other H2O emission-line strengths scale as suggested by Zubko and Elitzur.

User Experience Evaluation of a Smoking Cessation App in People With Serious Mental Illness

PubMed Central

Rizo, Javier; Kientz, Julie A.; McDonell, Michael G.; Ries, Richard K.; Sobel, Kiley

2016-01-01

Introduction: Smoking rates among people with serious mental illness are 3 to 4 times higher than the general population, yet currently there are no smoking cessation apps specifically designed to address this need. We report the results of a User Experience (UX) evaluation of a National Cancer Institute smoking cessation app, QuitPal, and provide user centered design data that can be used to tailor smoking cessation apps for this population. Methods: Two hundred forty hours of field experience with QuitPal, 10 hours of recorded interviews and task performances, usage logs and a self-reported usability scale, informed the results of our study. Participants were five individuals recruited from a community mental health clinic with a reported serious mental illness history. Performance, self-reports, usage logs and interview data were triangulated to identify critical usability errors and UX themes emerging from this population. Results: Data suggests QuitPal has below average levels of usability, elevated time on task performances and required considerable amounts of guidance. UX themes provided critical information to tailor smoking cessation apps for this population, such as the importance of breaking down “cessation” into smaller steps and use of a reward system. Conclusions: This is the first study to examine the UX of a smoking cessation app among people with serious mental illness. Data from this study will inform future research efforts to expand the effectiveness and reach of smoking cessation apps for this highly nicotine dependent yet under-served population. Implications: Data from this study will inform future research efforts to expand the effectiveness and reach of smoking cessation apps for people with serious mental illness, a highly nicotine dependent yet under-served population. PMID:26581430

Arp 148& - Mayall Object

NASA Image and Video Library

2008-04-24

Arp 148 is nicknamed Mayall object and is located in the constellation of Ursa Major, the Great Bear, about 500 million light-years away. This image is part of a large collection of images of merging galaxies taken by NASA Hubble Space Telescope.

Nonlinear Propagation of Alfven Waves Driven by Observed Photospheric Motions: Application to the Coronal Heating and Spicule Formation

NASA Astrophysics Data System (ADS)

Matsumoto, Takuma; Shibata, Kazunari

We have performed MHD simulations of Alfven wave propagation along an open ux tube in the solar atmosphere. In our numerical model, Alfven waves are generated by the photospheric granular motion. As the wave generator, we used a derived temporal spectrum of the photo-spheric granular motion from G-band movies of Hinode/SOT. It is shown that the total energy ux at the corona becomes larger and the transition region height becomes higher in the case when we use the observed spectrum rather than white/pink noise spectrum as the wave gener-ator. This difference can be explained by the Alfven wave resonance between the photosphere and the transition region. After performing Fourier analysis on our numerical results, we have found that the region between the photosphere and the transition region becomes an Alfven wave resonant cavity. We have conrmed that there are at least three resonant frequencies, 1, 3 and 5 mHz, in our numerical model. Alfven wave resonance is one of the most effective mechanisms to explain the dynamics of the spicules and the sufficient energy ux to heat the corona.

Relativistic MHD simulations of collision-induced magnetic dissipation in poynting-flux-dominated jets/outflows

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

Deng, Wei; Li, Hui; Zhang, Bing

We perform 3D relativistic ideal MHD simulations to study the collisions between high-σ (Poynting- ux-dominated) blobs which contain both poloidal and toroidal magnetic field components. This is meant to mimic the interactions inside a highly variable Poynting- ux-dominated jet. We discover a significant electromagnetic field (EMF) energy dissipation with an Alfvenic rate with the efficiency around 35%. Detailed analyses show that this dissipation is mostly facilitated by the collision-induced magnetic reconnection. Additional resolution and parameter studies show a robust result that the relative EMF energy dissipation efficiency is nearly independent of the numerical resolution or most physical parameters in themore » relevant parameter range. The reconnection outflows in our simulation can potentially form the multi-orientation relativistic mini-jets as needed for several analytical models. We also find a linear relationship between the σ values before and after the major EMF energy dissipation process. In conclusion, our results give support to the proposed astrophysical models that invoke signi cant magnetic energy dissipation in Poynting- ux-dominated jets, such as the internal collision-induced magnetic reconnection and turbulence (ICMART) model for GRBs, and reconnection triggered mini-jets model for AGNs.« less

Relativistic MHD simulations of collision-induced magnetic dissipation in poynting-flux-dominated jets/outflows

DOE PAGES

Deng, Wei; Li, Hui; Zhang, Bing; ...

2015-05-29

We perform 3D relativistic ideal MHD simulations to study the collisions between high-σ (Poynting- ux-dominated) blobs which contain both poloidal and toroidal magnetic field components. This is meant to mimic the interactions inside a highly variable Poynting- ux-dominated jet. We discover a significant electromagnetic field (EMF) energy dissipation with an Alfvenic rate with the efficiency around 35%. Detailed analyses show that this dissipation is mostly facilitated by the collision-induced magnetic reconnection. Additional resolution and parameter studies show a robust result that the relative EMF energy dissipation efficiency is nearly independent of the numerical resolution or most physical parameters in themore » relevant parameter range. The reconnection outflows in our simulation can potentially form the multi-orientation relativistic mini-jets as needed for several analytical models. We also find a linear relationship between the σ values before and after the major EMF energy dissipation process. In conclusion, our results give support to the proposed astrophysical models that invoke signi cant magnetic energy dissipation in Poynting- ux-dominated jets, such as the internal collision-induced magnetic reconnection and turbulence (ICMART) model for GRBs, and reconnection triggered mini-jets model for AGNs.« less

Ferromagnetism and Crystalline Electric Field Effects in Cubic UX2Zn20 (X=Co, Rh, Ir)

NASA Astrophysics Data System (ADS)

Bauer, E. D.; Ronning, F.; Silhanek, A.; Harrison, N.; Thompson, J. D.; Sarrao, J. L.; Movshovich, R.; Hundley, M. F.; Jaime, M.; Daniel, E.; Booth, C. H.

2006-03-01

The properties of a new class of cubic UX2Zn20 (X=Co, Rh, Ir) heavy fermion compounds have been investigated by means of magnetic susceptibility, specific heat, electrical resistivity, and x-ray absorption spectroscopy. Both UCo2Zn20 and URh2Zn20 show peaks in C(T) and χ(T) at ˜5-10 K suggesting the presence of crystalline electric field (CEF) effects in these materials, i.e., a localized 5f^2 configuration of uranium. In addition, measurements in high magnetic fields up to 40 T are consistent with a CEF model of a nonmagnetic ground state and a magnetic first excited state separated by ˜ 20 K. In contrast, UIr2Zn20 exhibits a first-order ferromagnetic transition at Tc=2.75 K with a saturation moment μsat=0.5 μB in the ferromagnetic state. All compounds in this series are heavy fermion materials with enhanced electronic specific heat coefficients γ˜ 150-300 mJ/molK^2. The physical properties of UX2Zn20 (X=Co, Rh, Ir) will be discussed.

Towards a holistic assessment of the user experience with hybrid BCIs.

PubMed

Lorenz, Romy; Pascual, Javier; Blankertz, Benjamin; Vidaurre, Carmen

2014-06-01

In recent years, brain-computer interfaces (BCIs) have become mature enough to immensely benefit from the expertise and tools established in the field of human-computer interaction (HCI). One of the core objectives in HCI research is the design of systems that provide a pleasurable user experience (UX). While the majority of BCI studies exclusively evaluate common efficiency measures such as classification accuracy and speed, single research groups have begun to look at further usability aspects such as ease of use, workload and learnability. However, these evaluation metrics only cover pragmatic aspects of UX while still not considering the hedonic quality of UX. In order to gain a holistic perspective on UX, hedonic quality aspects such as motivation and frustration were also taken into account for our evaluation of three BCI-driven interfaces, which were proposed to be used as a two-stage neuroprosthetic control within the EU project MUNDUS. At the first stage, one of six possible actions was selected and either confirmed or cancelled at the second stage. For the experiment, a solely event-related-potential-based interface (ERP-ERP) and two hybrid solutions were tested that were controlled by ERP and motor imagery (MI)--resulting in the two possible combinations: ERP selection/MI confirmation (ERP-MI) or MI selection/ERP confirmation (MI-ERP). Behavioural, subjective and encephalographic (EEG) data of 12 healthy subjects were collected during an online experiment with the three graphical user interfaces (GUIs). Results showed a significantly greater pragmatic quality (in terms of accuracy, efficiency, workload, use quality and learnability) for the ERP-ERP and ERP-MI GUIs in contrast to the MI-ERP GUI. Consequently, the MI-ERP GUI is least suited for use as a neuroprosthetic control. With respect to the comparison of the ERP-ERP and ERP-MI GUIs, no significant differences in pragmatic and hedonic quality of UX were found. Since throughout better results were obtained for the conventional approach and it was most preferred by the subjects, the ERP-ERP GUI seems more suitable for its deployment in actual end-users. Nevertheless, for individuals with stable MI patterns, the hybrid interface can be provided as an additional option of choice within the MUNDUS framework. Although the paramount goal in BCI research still remains the improvement of classification accuracy and communication speed, it is of significance to note that it is equally important for end-users to keep up their motivation and prevent frustration. By including pragmatic as well as hedonic quality aspects, this study is the first effort to gain a holistic perspective of the UX while interacting with BCI-driven assistive technology aimed at actual end-users. The broad-scale methodology provided valuable insights into the underlying dynamics causing the users' experience to differ across the GUIs. The results will be used to refine a BCI-driven neuroprosthesis and test it with end-users.

Towards a holistic assessment of the user experience with hybrid BCIs

NASA Astrophysics Data System (ADS)

Lorenz, Romy; Pascual, Javier; Blankertz, Benjamin; Vidaurre, Carmen

2014-06-01

Objective. In recent years, brain-computer interfaces (BCIs) have become mature enough to immensely benefit from the expertise and tools established in the field of human-computer interaction (HCI). One of the core objectives in HCI research is the design of systems that provide a pleasurable user experience (UX). While the majority of BCI studies exclusively evaluate common efficiency measures such as classification accuracy and speed, single research groups have begun to look at further usability aspects such as ease of use, workload and learnability. However, these evaluation metrics only cover pragmatic aspects of UX while still not considering the hedonic quality of UX. In order to gain a holistic perspective on UX, hedonic quality aspects such as motivation and frustration were also taken into account for our evaluation of three BCI-driven interfaces, which were proposed to be used as a two-stage neuroprosthetic control within the EU project MUNDUS. Approach. At the first stage, one of six possible actions was selected and either confirmed or cancelled at the second stage. For the experiment, a solely event-related-potential-based interface (ERP-ERP) and two hybrid solutions were tested that were controlled by ERP and motor imagery (MI)—resulting in the two possible combinations: ERP selection/MI confirmation (ERP-MI) or MI selection/ERP confirmation (MI-ERP). Behavioural, subjective and encephalographic (EEG) data of 12 healthy subjects were collected during an online experiment with the three graphical user interfaces (GUIs). Main results. Results showed a significantly greater pragmatic quality (in terms of accuracy, efficiency, workload, use quality and learnability) for the ERP-ERP and ERP-MI GUIs in contrast to the MI-ERP GUI. Consequently, the MI-ERP GUI is least suited for use as a neuroprosthetic control. With respect to the comparison of the ERP-ERP and ERP-MI GUIs, no significant differences in pragmatic and hedonic quality of UX were found. Since throughout better results were obtained for the conventional approach and it was most preferred by the subjects, the ERP-ERP GUI seems more suitable for its deployment in actual end-users. Nevertheless, for individuals with stable MI patterns, the hybrid interface can be provided as an additional option of choice within the MUNDUS framework. Significance. Although the paramount goal in BCI research still remains the improvement of classification accuracy and communication speed, it is of significance to note that it is equally important for end-users to keep up their motivation and prevent frustration. By including pragmatic as well as hedonic quality aspects, this study is the first effort to gain a holistic perspective of the UX while interacting with BCI-driven assistive technology aimed at actual end-users. The broad-scale methodology provided valuable insights into the underlying dynamics causing the users’ experience to differ across the GUIs. The results will be used to refine a BCI-driven neuroprosthesis and test it with end-users.

Optimization method for an evolutional type inverse heat conduction problem

NASA Astrophysics Data System (ADS)

Deng, Zui-Cha; Yu, Jian-Ning; Yang, Liu

2008-01-01

This paper deals with the determination of a pair (q, u) in the heat conduction equation u_t-u_{xx}+q(x,t)u=0, with initial and boundary conditions u(x,0)=u_0(x),\\qquad u_x|_{x=0}=u_x|_{x=1}=0, from the overspecified data u(x, t) = g(x, t). By the time semi-discrete scheme, the problem is transformed into a sequence of inverse problems in which the unknown coefficients are purely space dependent. Based on the optimal control framework, the existence, uniqueness and stability of the solution (q, u) are proved. A necessary condition which is a couple system of a parabolic equation and parabolic variational inequality is deduced.

Photometry, polarimetry, spectroscopy, and spectropolarimetry of the enigmatic Wolf-Rayet star EZ Canis Majoris

NASA Technical Reports Server (NTRS)

Robert, Carmelle; Moffat, Anthony F. J.; Drissen, Laurent; Lamontagne, Robert; Seggewiss, Wilhelm; Niemela, Virpi S.; Cerruti, Miguel A.; Barrett, Paul; Bailey, Jeremy; Garcia, Jorge

1992-01-01

New observations of the peculiar Wolf-Rayet star EZ Canis Majoris collected since 1987 are presented, and photometric, polarimetric, spectroscopic, and spectropolarimetric data are discussed. Linear polarization data are well fitted with an eccentric binary model where an additional free parameter is included to allow for epoch-dependent changes of the geometrical electron distribution in the W-R envelope. This yields a set of basic parameters, including an eccentricity e = 0.39 +/- 0.02 and an orbital inclination i = 114 deg +/- 3 deg. The spectroscopic data show global profile variations for all three observed strong emission lines He II 5412 A, C IV 5807 A, and He I 5876 A. Radial velocities of the lines vary with the 3.766-day period. Radially expanding inhomogeneities are superposed on the line profiles and variable polarization in the lines is observed.

The 3D morphology of the ejecta surrounding VY Canis Majoris

NASA Astrophysics Data System (ADS)

Jones, Terry Jay; Humphreys, Roberta M.; Helton, L. Andrew

2007-03-01

We use second epoch images taken with WFPC2 on the HST and imaging polarimetry taken with the HST/ACS/HRC to explore the three dimensional structure of the circumstellar dust distribution around the red supergiant VY Canis Majoris. Transverse motions, combined with radial velocities, provide a picture of the kinematics of the ejecta, including the total space motions. The fractional polarization and photometric colors provide an independent method of locating the physical position of the dust along the line-of-sight. Most of the individual arc-like features and clumps seen in the intensity image are also features in the fractional polarization map, and must be distinct geometric objects. The location of these features in the ejecta of VY CMa using kinematics and polarimetry agree well with each other, and strongly suggest they are the result of relatively massive ejections, probably associated with magnetic fields.

Distribution of SO_{2} and so in the Envelope of Vy-Canis Majoris: Insight Into Circumstellar Sulfur Chemistry

NASA Astrophysics Data System (ADS)

Adande, Gilles; Ziurys, L. M.

2013-06-01

Millimeter wave observations of SO_{2} and SO in the envelope of the O-rich supergiant VY-Canis Majoris have been conducted with the Submillimeter Telescope (SMT) of the Arizona Radio Observatory, between 210 and 290 GHz. A non LTE radiative transfer code has been written to fit the line profile of 22 lines of SO_{2} and 5 transitions of SO, and model their abundance and distribution within the circumstellar envelope. The rotational levels involved span a wide energy range, from 13 cm^{-1} to 104 cm^{-1} for SO_{2}, and 17 to 40 cm^{-1} for SO. The high number of transitions fitted provides strong constraints on the excitation conditions, hydrogen density and kinetic temperatures. The results will be discussed in relation to the formation processes and chemistry of these two species in O-rich molecular envelopes.

1ES 1113+432: Luminous, soft X-ray outburst from a nearby cataclysmic variable (AR Ursae Majoris)

NASA Technical Reports Server (NTRS)

Remillard, R. A.; Schachter, J. F.; Silber, A. D.; Slane, P.

1994-01-01

A remarkable X-ray transient from the Einstein Slew Survey, 1 ES 1113+432, is identified with a nearby, short-period cataclysmic variable. Wenzel (1993) has confirmed that the optical counterpart is the variable star, AR UMa (cataloged as 'semiregular'), erroneously reported 5.7 min southeast of the true position. One of the Einstein slew observations recorded a flux of 43 IPC counts/s, which is an order of magnitude above the flux observed from the brightest cataclysmic variables in other X-ray surveys. The outburst spectrum is extremely 'soft,' with an implied blackbody temperature of approximately 22 eV. The optical counterpart (V = 16.5) exhibits a strong UV component, TiO bands from an M star, and broadened Balmer emission lines. Optical states as bright as V approx. 13 were found on photographs from the Harvard Plate Library, confirming outburst behavior in the optical counterpart. The historical photographic record suggests that 1ES 1113+432 remains in a low-accretion state most of the time. Both of the soft X-ray spectrum and the transitions between high and low-accretion states are suggestive of the AM Her (magnetic) subclass. Photometric observations in the I band show 0.18 mag modulations at a period of 0.966 hr. These are interpreted as ellipsiodal variations in the secondary star for a binary period of 1.932 hr, which is near the lower boundary of the 'period gap' in the histogram, of orbital periods of accreting white dwarfs. Thus 1ES 1113+432 provides the rare opportunity to study a secondary star in a cataclysmic binary that has evolved through the period gap. The optical spectral features from the secondary imply a spectral type of approximately M6 and a distance of approximately 88 pc. The peak luminosity in the soft X-ray component (unabsorbed) is then estimated to be 3 X 10(exp 33) ergs/s, assuming emission from a blackbody slab with a temperature of 22 eV. While this luminosity is higher than previous measures of the soft X-ray component, it does not exceed the amount of radiation that could be emitted from the accretion-heated surface of a white dwarf.

MHC-I affects infection intensity but not infection status with a frequent avian malaria parasite in blue tits.

PubMed

Westerdahl, Helena; Stjernman, Martin; Råberg, Lars; Lannefors, Mimi; Nilsson, Jan-Åke

2013-01-01

Host resistance against parasites depends on three aspects: the ability to prevent, control and clear infections. In vertebrates the immune system consists of innate and adaptive immunity. Innate immunity is particularly important for preventing infection and eradicating established infections at an early stage while adaptive immunity is slow, but powerful, and essential for controlling infection intensities and eventually clearing infections. Major Histocompatibility Complex (MHC) molecules are central in adaptive immunity, and studies on parasite resistance and MHC in wild animals have found effects on both infection intensity (parasite load) and infection status (infected or not). It seems MHC can affect both the ability to control infection intensities and the ability to clear infections. However, these two aspects have rarely been considered simultaneously, and their relative importance in natural populations is therefore unclear. Here we investigate if MHC class I genotype affects infection intensity and infection status with a frequent avian malaria infection Haemoproteus majoris in a natural population of blue tits Cyanistes caeruleus. We found a significant negative association between a single MHC allele and infection intensity but no association with infection status. Blue tits that carry a specific MHC allele seem able to suppress H. majoris infection intensity, while we have no evidence that this allele also has an effect on clearance of the H. majoris infection, a result that is in contrast with some previous studies of MHC and avian malaria. A likely explanation could be that the clearance rate of avian malaria parasites differs between avian malaria lineages and/or between avian hosts.

MHC-I Affects Infection Intensity but Not Infection Status with a Frequent Avian Malaria Parasite in Blue Tits

PubMed Central

Westerdahl, Helena; Stjernman, Martin; Råberg, Lars; Lannefors, Mimi; Nilsson, Jan-Åke

2013-01-01

Host resistance against parasites depends on three aspects: the ability to prevent, control and clear infections. In vertebrates the immune system consists of innate and adaptive immunity. Innate immunity is particularly important for preventing infection and eradicating established infections at an early stage while adaptive immunity is slow, but powerful, and essential for controlling infection intensities and eventually clearing infections. Major Histocompatibility Complex (MHC) molecules are central in adaptive immunity, and studies on parasite resistance and MHC in wild animals have found effects on both infection intensity (parasite load) and infection status (infected or not). It seems MHC can affect both the ability to control infection intensities and the ability to clear infections. However, these two aspects have rarely been considered simultaneously, and their relative importance in natural populations is therefore unclear. Here we investigate if MHC class I genotype affects infection intensity and infection status with a frequent avian malaria infection Haemoproteus majoris in a natural population of blue tits Cyanistes caeruleus. We found a significant negative association between a single MHC allele and infection intensity but no association with infection status. Blue tits that carry a specific MHC allele seem able to suppress H. majoris infection intensity, while we have no evidence that this allele also has an effect on clearance of the H. majoris infection, a result that is in contrast with some previous studies of MHC and avian malaria. A likely explanation could be that the clearance rate of avian malaria parasites differs between avian malaria lineages and/or between avian hosts. PMID:24023631

Structure and mechanism of human UDP-xylose synthase: evidence for a promoting role of sugar ring distortion in a three-step catalytic conversion of UDP-glucuronic acid.

PubMed

Eixelsberger, Thomas; Sykora, Sabine; Egger, Sigrid; Brunsteiner, Michael; Kavanagh, Kathryn L; Oppermann, Udo; Brecker, Lothar; Nidetzky, Bernd

2012-09-07

UDP-xylose synthase (UXS) catalyzes decarboxylation of UDP-D-glucuronic acid to UDP-xylose. In mammals, UDP-xylose serves to initiate glycosaminoglycan synthesis on the protein core of extracellular matrix proteoglycans. Lack of UXS activity leads to a defective extracellular matrix, resulting in strong interference with cell signaling pathways. We present comprehensive structural and mechanistic characterization of the human form of UXS. The 1.26-Å crystal structure of the enzyme bound with NAD(+) and UDP reveals a homodimeric short-chain dehydrogenase/reductase (SDR), belonging to the NDP-sugar epimerases/dehydratases subclass. We show that enzymatic reaction proceeds in three chemical steps via UDP-4-keto-D-glucuronic acid and UDP-4-keto-pentose intermediates. Molecular dynamics simulations reveal that the D-glucuronyl ring accommodated by UXS features a marked (4)C(1) chair to B(O,3) boat distortion that facilitates catalysis in two different ways. It promotes oxidation at C(4) (step 1) by aligning the enzymatic base Tyr(147) with the reactive substrate hydroxyl and it brings the carboxylate group at C(5) into an almost fully axial position, ideal for decarboxylation of UDP-4-keto-D-glucuronic acid in the second chemical step. The protonated side chain of Tyr(147) stabilizes the enolate of decarboxylated C(4) keto species ((2)H(1) half-chair) that is then protonated from the Si face at C(5), involving water coordinated by Glu(120). Arg(277), which is positioned by a salt-link interaction with Glu(120), closes up the catalytic site and prevents release of the UDP-4-keto-pentose and NADH intermediates. Hydrogenation of the C(4) keto group by NADH, assisted by Tyr(147) as catalytic proton donor, yields UDP-xylose adopting the relaxed (4)C(1) chair conformation (step 3).

Probing the origin of UX Ori-type variability in the YSO binary CO Ori with VLTI/GRAVITY

NASA Astrophysics Data System (ADS)

Davies, C. L.; Kreplin, A.; Kluska, J.; Hone, E.; Kraus, S.

2018-03-01

The primary star in the young stellar object binary CO Ori displays UX Ori-type variability: irregular, high amplitude optical, and near-infrared photometric fluctuations where flux minima coincide with polarization maxima. This is attributed to changes in local opacity. In CO Ori A, these variations exhibit a 12.4 yr cycle. Here, we investigate the physical origin of the fluctuating opacity and its periodicity using interferometric observations of CO Ori obtained using VLTI/GRAVITY. Continuum K-band circum-primary and circum-secondary emission are marginally spatially resolved for the first time, while Brγ emission is detected in the spectrum of the secondary. We estimate a spectral type range for CO Ori B of K2-K5 assuming visual extinction, AV = 2 and a distance of 430 pc. From geometric modelling of the continuum visibilities, the circum-primary emission is consistent with a central point source plus a Gaussian component with a full width at half-maximum of 2.31 ± 0.04 mas, inclined at 30.2° ± 2.2° and with a major axis position angle of 40° ± 6°. This inclination is lower than that reported for the discs of other UX Ori-type stars, providing a first indication that the UX Ori phenomena may arise through fluctuations in circum-stellar material exterior to a disc, for example, in a dusty outflow. An additional wide, symmetric Gaussian component is required to fit the visibilities of CO Ori B, signifying a contribution from scattered light. Finally, closure phases of CO Ori A were used to investigate whether the 12.4 yr periodicity is associated with an undetected third component, as has been previously suggested. We rule out any additional companions contributing more than 3.6 per cent to the K-band flux within ˜7.3-20 mas of CO Ori A.

User Experience Evaluation of a Smoking Cessation App in People With Serious Mental Illness.

PubMed

Vilardaga, Roger; Rizo, Javier; Kientz, Julie A; McDonell, Michael G; Ries, Richard K; Sobel, Kiley

2016-05-01

Smoking rates among people with serious mental illness are 3 to 4 times higher than the general population, yet currently there are no smoking cessation apps specifically designed to address this need. We report the results of a User Experience (UX) evaluation of a National Cancer Institute smoking cessation app, QuitPal, and provide user centered design data that can be used to tailor smoking cessation apps for this population. Two hundred forty hours of field experience with QuitPal, 10 hours of recorded interviews and task performances, usage logs and a self-reported usability scale, informed the results of our study. Participants were five individuals recruited from a community mental health clinic with a reported serious mental illness history. Performance, self-reports, usage logs and interview data were triangulated to identify critical usability errors and UX themes emerging from this population. Data suggests QuitPal has below average levels of usability, elevated time on task performances and required considerable amounts of guidance. UX themes provided critical information to tailor smoking cessation apps for this population, such as the importance of breaking down "cessation" into smaller steps and use of a reward system. This is the first study to examine the UX of a smoking cessation app among people with serious mental illness. Data from this study will inform future research efforts to expand the effectiveness and reach of smoking cessation apps for this highly nicotine dependent yet under-served population. Data from this study will inform future research efforts to expand the effectiveness and reach of smoking cessation apps for people with serious mental illness, a highly nicotine dependent yet under-served population. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Low-latency situational awareness for UxV platforms

NASA Astrophysics Data System (ADS)

Berends, David C.

2012-06-01

Providing high quality, low latency video from unmanned vehicles through bandwidth-limited communications channels remains a formidable challenge for modern vision system designers. SRI has developed a number of enabling technologies to address this, including the use of SWaP-optimized Systems-on-a-Chip which provide Multispectral Fusion and Contrast Enhancement as well as H.264 video compression. Further, the use of salience-based image prefiltering prior to image compression greatly reduces output video bandwidth by selectively blurring non-important scene regions. Combined with our customization of the VLC open source video viewer for low latency video decoding, SRI developed a prototype high performance, high quality vision system for UxV application in support of very demanding system latency requirements and user CONOPS.

A minimum entropy principle in the gas dynamics equations

NASA Technical Reports Server (NTRS)

Tadmor, E.

1986-01-01

Let u(x bar,t) be a weak solution of the Euler equations, governing the inviscid polytropic gas dynamics; in addition, u(x bar, t) is assumed to respect the usual entropy conditions connected with the conservative Euler equations. We show that such entropy solutions of the gas dynamics equations satisfy a minimum entropy principle, namely, that the spatial minimum of their specific entropy, (Ess inf s(u(x,t)))/x, is an increasing function of time. This principle equally applies to discrete approximations of the Euler equations such as the Godunov-type and Lax-Friedrichs schemes. Our derivation of this minimum principle makes use of the fact that there is a family of generalized entrophy functions connected with the conservative Euler equations.

Local well-posedness for dispersion generalized Benjamin-Ono equations in Sobolev spaces

NASA Astrophysics Data System (ADS)

Guo, Zihua

We prove that the Cauchy problem for the dispersion generalized Benjamin-Ono equation ∂u+|∂u+uu=0, u(x,0)=u(x), is locally well-posed in the Sobolev spaces H for s>1-α if 0⩽α⩽1. The new ingredient is that we generalize the methods of Ionescu, Kenig and Tataru (2008) [13] to approach the problem in a less perturbative way, in spite of the ill-posedness results of Molinet, Saut and Tzvetkov (2001) [21]. Moreover, as a bi-product we prove that if 0<α⩽1 the corresponding modified equation (with the nonlinearity ±uuu) is locally well-posed in H for s⩾1/2-α/4.

Adiabatic decay of internal solitons due to Earth's rotation within the framework of the Gardner-Ostrovsky equation

NASA Astrophysics Data System (ADS)

Obregon, Maria; Raj, Nawin; Stepanyants, Yury

2018-03-01

The adiabatic decay of different types of internal wave solitons caused by the Earth's rotation is studied within the framework of the Gardner-Ostrovsky equation. The governing equation describing such processes includes quadratic and cubic nonlinear terms, as well as the Boussinesq and Coriolis dispersions: (ut + c ux + α u ux + α1 u2 ux + β uxxx)x = γ u. It is shown that at the early stage of evolution solitons gradually decay under the influence of weak Earth's rotation described by the parameter γ. The characteristic decay time is derived for different types of solitons for positive and negative coefficients of cubic nonlinearity α1 (both signs of that parameter may occur in the oceans). The coefficient of quadratic nonlinearity α determines only a polarity of solitary wave when α1 < 0 or the asymmetry of solitary waves of opposite polarity when α1 > 0. It is found that the adiabatic theory describes well the decay of solitons having bell-shaped profiles. In contrast to that, large amplitude table-top solitons, which can exist when α1 is negative, are structurally unstable. Under the influence of Earth's rotation, they transfer first to the bell-shaped solitons, which decay then adiabatically. Estimates of the characteristic decay time of internal solitons are presented for the real oceanographic conditions.

Are neutrons precursors of solar flares?

NASA Astrophysics Data System (ADS)

Martirosyan, H.

2001-08-01

The analysis of data of a worldwide network of neutron monitors (NM) shows, that at local noon and during approximately 4 hours after, the NM sometimes register statistically significant excess. Enhancement of count rate is approxi-mately ≈ 1.5÷2%. Depending on the geographical coordinates the time slice is determined, during which the global increase of a registered ux (characteristic time of the order of tens of hours) is observed. These data are correlated with data from space-borne sensors, proving significant increase ( ≈ 5 ÷ 10 times) of the low energy protons and electrons in near-earth space. In both cases the ux enhancement during tenths of hours is proceeding by an impulse phase of the next solar are. The analysis of data allows to put forward a hypothesis that the enhancement of the protons and electrons ux is stipulated by decay of solar neutrons with energies 10 ÷ 30 MeV . These neutrons during tenths of hours before an impulse phase of a are are born in active areas of the Sun, as a product of thermonuclear reactions (D + d → He3 + n, T + d → He4 + n). The part of neutrons are decaying in the interplanetary space, and part of high en-ergy neutrons (En > 20 V ) penetrate through terrestrial atmosphere (with probability ≈ 10-7 and are registered by neutron monitors.

Indirect dark matter searches in the dwarf satellite galaxy Ursa Major II with the MAGIC telescopes

NASA Astrophysics Data System (ADS)

Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Arcaro, C.; Baack, D.; Babić, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berse, R. Ch.; Berti, A.; Bhattacharyya, W.; Biland, A.; Blanch, O.; Bonnoli, G.; Carosi, R.; Carosi, A.; Ceribella, G.; Chatterjee, A.; Colak, S. M.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; Delfino, M.; Delgado, J.; Di Pierro, F.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Elsaesser, D.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Ishio, K.; Konno, Y.; Kubo, H.; Kushida, J.; Kuveždić, D.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Maggio, C.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Masuda, S.; Mazin, D.; Mielke, K.; Minev, M.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Moreno, V.; Moretti, E.; Nagayoshi, T.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nigro, C.; Nilsson, K.; Ninci, D.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pedaletti, G.; Peresano, M.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Righi, C.; Rugliancich, A.; Saito, T.; Satalecka, K.; Schweizer, T.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takahashi, M.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Teshima, M.; Torres-Albà, N.; Treves, A.; Tsujimoto, S.; Vanzo, G.; Vazquez Acosta, M.; Vovk, I.; Ward, J. E.; Will, M.; Zarić, D.

2018-03-01

The dwarf spheroidal galaxy Ursa Major II (UMaII) is believed to be one of the most dark-matter dominated systems among the Milky Way satellites and represents a suitable target for indirect dark matter (DM) searches. The MAGIC telescopes carried out a deep observation campaign on UMaII between 2014 and 2016, collecting almost one hundred hours of good-quality data. This campaign enlarges the pool of DM targets observed at very high energy (E gtrsim 50 GeV) in search for signatures of DM annihilation in the wide mass range between ~100 GeV and ~100 TeV. To this end, the data are analyzed with the full likelihood analysis, a method based on the exploitation of the spectral information of the recorded events for an optimal sensitivity to the explored DM models. We obtain constraints on the annihilation cross-section for different channels that are among the most robust and stringent achieved so far at the TeV mass scale from observations of dwarf satellite galaxies.

High Resolution Near-IR Imaging of VY Canis Majoris with LBT / LMIRCam (2 - 5 μm)

NASA Astrophysics Data System (ADS)

Shenoy, Dinesh; Jones, T. J.; Humphreys, R. M.; LMIRCam Instrument Team

2013-06-01

HST imaging of the famous red hypergiant VY Canis Majoris shows a complex circumstellar reflection nebula indicative of multiple asymmetric ejection episodes. Constructing a more complete picture of the mass loss mechanism compels extending high resolution imaging of massive stars such as VY CMa into the near-infrared, where the mechanism for emission from circumstellar ejecta transitions from scattering to thermal. We present LBT/LMIRCam observations of VY CMa at Ks (2.2 μm), L' (3.8 μm) and M (4.9 μm) at sub-arcsecond resolution, comparable to the HST in the optical. The peculiar Southwest (SW) Clump, first identified as a highly reddened feature seen only at the longest wavelength (1 μm) in the HST images, appears bright in the three LMIRCam filters. The SW Clump is found to be optically thick at all three wavelengths. A silicate grain model yields a lower limit mass on the order of 7E-4 M⊙

Physical Parameters of Components in Close Binary Systems: IV

NASA Astrophysics Data System (ADS)

Gazeas, K. D.; Baran, A.; Niarchos, P.; Zola, S.; Kreiner, J. M.; Ogloza, W.; Rucinski, S. M.; Zakrzewski, B.; Siwak, M.; Pigulski, A.; Drozdz, M.

2005-03-01

The paper presents new geometric, photometric and absolute parameters, derived from combined spectroscopic and photometric solutions, for ten contact binary systems. The analysis shows that three systems (EF Boo, GM Dra and SW Lac) are of W-type with shallow to moderate contact. Seven systems (V417 Aql, AH Aur, YY CrB, UX Eri, DZ Psc, GR Vir and NN Vir) are of A-type in a deep contact configuration. For six systems (V417 Aql, YY CrB, GM Dra, UX Eri, SW Lac and GR Vir) a spot model is introduced to explain the O'Connell effect in their light curves. The photometric and geometric elements of the systems are combined with the spectroscopic data taken at David Dunlap Observatory to yield the absolute parameters of the components.

PHOTOMETRIC, SPECTROSCOPIC, AND ORBITAL PERIOD STUDY OF THREE EARLY-TYPE SEMI-DETACHED SYSTEMS: XZ AQL, UX HER, AND AT PEG

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

Zola, S.; Baştürk, Ö.; Şenavcı, H. V.

2016-08-01

In this paper, we present a combined photometric, spectroscopic, and orbital period study of three early-type eclipsing binary systems: XZ Aql, UX Her, and AT Peg. As a result, we have derived the absolute parameters of their components and, on that basis, we discuss their evolutionary states. Furthermore, we compare their parameters with those of other binary systems and with theoretical models. An analysis of all available up-to-date times of minima indicated that all three systems studied here show cyclic orbital changes; their origin is discussed in detail. Finally, we performed a frequency analysis for possible pulsational behavior, and asmore » a result we suggest that XZ Aql hosts a δ Scuti component.« less

The Data Base for the May 1979 Marine Surface Layer Micrometeorological Experiment at San Nicolas Island, California.

DTIC Science & Technology

1982-05-07

ATIO VE LOC I TY HUMIDITY TEMP. L ENGTH ClIFF. 72% 7TO 160 4% 53% IS 5% A8t RZ lit 492 29% 23% END Of DATA RIiM 29 MARINE SURFACE LAYER...DRAG NO.AT GMM AlTOIM FL UX FLUX FLUX FL UX FLU X RTATIO VK LOC ITTY HUtMIDITY TEMP. LEN4GTH COE. 160% 161% 116% 167% 128% 9% 124% 295% s8% 109% 71...SCC PSI 90951!4 DRAG; NT, VT "MXT ’tI TIM ELS L X H Sy I 1(09rU F LT PtX ATIO VE LOC ITY ((IIDITIY TE MP. L EM!.TIH ItF 11% (1, .14% Il 195 Tx 5% 2A

Heat asymptotics for nonminimal Laplace type operators and application to noncommutative tori

NASA Astrophysics Data System (ADS)

Iochum, B.; Masson, T.

2018-07-01

Let P be a Laplace type operator acting on a smooth hermitean vector bundle V of fiber CN over a compact Riemannian manifold given locally by P = - [gμν u(x) ∂μ∂ν +vν(x) ∂ν + w(x) ] where u ,vν , w are MN(C) -valued functions with u(x) positive and invertible. For any a ∈ Γ(End(V)) , we consider the asymptotics Tr(ae-tP) ∼ t↓0+ ∑r=0∞ ar(a , P) t (r - d) / 2 where the coefficients ar(a , P) can be written as an integral of the functions ar(a , P) (x) = tr [ a(x) Rr(x) ] . The computation of R2 is performed opening the opportunity to calculate the modular scalar curvature for noncommutative tori.

Origin of Slope Failure in the Ursa Region, Northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Stigall, J.; Dugan, B.

2008-12-01

We use one-dimensional fluid flow and stability models to predict the evolution of overpressure and stability conditions of IODP Expedition Sites U1322 and U1324 in the Ursa region, northern Gulf of Mexico. Simulations of homogenous mud deposited at 3 and 12 mm/yr for Sites U1322 and U1324, with permeability (k) on the order of 10-17m2 and bulk compressibility of .4 /MPa, predict overpressures up to .45MPa and 1MPa in shallow sediments (<200m below sea floor). With limit equilibrium calculations for an infinite slope, these overpressures equate to a factor of safety (FS) greater than 10 and 4.5 for a internal friction angle of 26° and a seafloor slope of 2°. This implies stability throughout the last 50,000 years. Seismic and core observations, however, document major slope failures that span the entire Ursa region. Permeability in this region is well constrained by laboratory experiments, so we investigate how pulsed (high-to-low) sedimentation rates could have created unstable conditions, FS <1. Models with periods of high sedimentation generate overpressure that create unstable conditions while maintaining the time-averaged sedimentation rates. Other factors which are not possible to simulate in one dimension, such as a complex basin geometry, also influence the conditions that caused the past failures. A two-dimensional model linking lateral flow between the sites with the interpreted geometry from seismic stratigraphy gives a better picture of the flow field and instability within the basin. Asymmetrical loading of permeable sediments could have created a lateral difference in pore pressures which would have driven lateral flow from Site U1324 to Site U1322 where overpressures are higher than our one-dimensional models suggest. We anticipate that two-dimensional models with transient sedimentation patterns will enhance our understanding of flow in marginally stable environments and triggers of slope failures in passive margin systems.

Functional and Evolutionary Characterization of a UDP-Xylose Synthase Gene from the Plant Pathogen Xylella fastidiosa, Involved in the Synthesis of Bacterial Lipopolysaccharide.

PubMed

Alencar, Valquíria Campos; Jabes, Daniela Leite; Menegidio, Fabiano Bezerra; Sassaki, Guilherme Lanzi; de Souza, Lucas Rodrigo; Puzer, Luciano; Meneghetti, Maria Cecília Zorél; Lima, Marcelo Andrade; Tersariol, Ivarne Luis Dos Santos; de Oliveira, Regina Costa; Nunes, Luiz R

2017-02-07

Xylella fastidiosa is a plant-infecting bacillus, responsible for many important crop diseases, such as Pierce's disease of vineyards, citrus variegated chlorosis, and coffee leaf scorch (CLS), among others. Recent genomic comparisons involving two CLS-related strains, belonging to X. fastidiosa subsp. pauca, revealed that one of them carries a frameshift mutation that inactivates a gene encoding an oxidoreductase of the short-chain dehydrogenase/reductase (SDR) superfamily, which may play important roles in determining structural variations in bacterial glycans and glycoconjugates. However, the exact nature of this SDR has been a matter of controversy, as different annotations of X. fastidiosa genomes have implicated it in distinct reactions. To confirm the nature of this mutated SDR, a comparative analysis was initially performed, suggesting that it belongs to a subgroup of SDR decarboxylases, representing a UDP-xylose synthase (Uxs). Functional assays, using a recombinant derivative of this enzyme, confirmed its nature as XfUxs, and carbohydrate composition analyses, performed with lipopolysaccharide (LPS) molecules obtained from different strains, indicate that inactivation of the X. fastidiosa uxs gene affects the LPS structure among CLS-related X. fastidiosa strains. Finally, a comparative sequence analysis suggests that this mutation is likely to result in a morphological and evolutionary hallmark that differentiates two subgroups of CLS-related strains, which may influence interactions between these bacteria and their plant and/or insect hosts.

VizieR Online Data Catalog: Very metal poor stars in MW halo (Mashonkina+, 2017)

NASA Astrophysics Data System (ADS)

Mashonkina, L.; Jablonka, P.; Sitnova, T.; Pakhomov, Yu; North, P.

2017-10-01

Tables 3 and 4 from the article are presented. They include the LTE and NLTE abundances from individual lines and average abundances of the investigated stars in the dSphs Sculptor (Scl), Ursa Minor (UMi), Fornax (Fnx), Sextans (Sex), Bootes I (Boo), UMa II, and Leo IV and the Milky Way (MW) halo. (3 data files).

Overview of pulsed-power-driven high-energy-density plasma research at the University of Michigan

NASA Astrophysics Data System (ADS)

McBride, R. D.; Campbell, P. C.; Miller, S. M.; Woolstrum, J. M.; Yager-Elorriaga, D. A.; Steiner, A. M.; Jordan, N. M.; Lau, Y. Y.; Gilgenbach, R. M.; Safronova, A. S.; Kantsyrev, V. L.; Shlyaptseva, V. V.; Shrestha, I. K.; Butcher, C. J.; Laity, G. R.; Leckbee, J. J.; Wisher, M. L.; Slutz, S. A.; Cuneo, M. E.

2017-10-01

The Michigan Accelerator for Inductive Z-pinch Experiments (MAIZE) is a 3-m-diameter, single-cavity Linear Transformer Driver (LTD) at the University of Michigan (UM). MAIZE supplies a fast electrical pulse (0-1 MA in 100 ns for matched loads) to various experimental configurations, including wire-array z-pinches and cylindrical foil loads. This talk will report on projects aimed at upgrading the MAIZE facility (e.g., a new power feed and new diagnostics) as well as various physics campaigns on MAIZE (e.g., radiation source development, power flow, implosion instabilities, and other projects relevant to the MagLIF program at Sandia). In addition to MAIZE, UM is constructing a second, smaller LTD facility consisting of four 1.25-m-diameter cavities. These cavities were previously part of Sandia's 21-cavity Ursa Minor facility. The status of the four Ursa Minor cavities at UM will also be presented. This research was funded in part by the University of Michigan, a Faculty Development Grant from the Nuclear Regulatory Commission, the NNSA under DOE Grant DE-NA0003047 for UNR, and Sandia National Laboratories under DOE-NNSA contract DE-NA0003525.

A spectroscopic search for colliding stellar winds in O-type close binary systems. III - 29 UW Canis Majoris

NASA Technical Reports Server (NTRS)

Wiggs, Michael S.; Gies, Douglas R.

1993-01-01

The orbital-phase variations in the optical emission lines and UV P Cygni lines of the massive O-type binary 29 UW Canis Majoris are investigated in a search for evidence of colliding winds. High SNR spectra of the H-alpha and He I 6678-A emission lines are presented, and radial velocity curves for several features associated with the photosphere of the more luminous primary star are given. The H-alpha features consists of a P Cygni component that shares the motion of the primary, and which probably originates at the base of its wind, and a broad, stationary emission component. It is proposed that the broad emission forms in a plane midway between the stars where the winds collide. A simple geometric model is used to show that this placement of the broad component can explain the lack of orbital velocity shifts, the near-constancy of the emission strength throughout the orbit, the large velocities associated with the H-alpha wings, and the constancy of the velocity range observed.

Distance to VY Canis Majoris with VERA

NASA Astrophysics Data System (ADS)

Choi, Yoon Kyung; Hirota, Tomoya; Honma, Mareki; Kobayashi, Hideyuki; Bushimata, Takeshi; Imai, Hiroshi; Iwadate, Kenzaburo; Jike, Takaaki; Kameno, Seiji; Kameya, Osamu; Kamohara, Ryuichi; Kan-Ya, Yukitoshi; Kawaguchi, Noriyuki; Kijima, Masachika; Kim, Mi Kyoung; Kuji, Seisuke; Kurayama, Tomoharu; Manabe, Seiji; Maruyama, Kenta; Matsui, Makoto; Matsumoto, Naoko; Miyaji, Takeshi; Nagayama, Takumi; Nakagawa, Akiharu; Nakamura, Kayoko; Oh, Chung Sik; Omodaka, Toshihiro; Oyama, Tomoaki; Sakai, Satoshi; Sasao, Tetsuo; Sato, Katsuhisa; Sato, Mayumi; Shibata, Katsunori M.; Tamura, Yoshiaki; Tsushima, Miyuki; Yamashita, Kazuyoshi

2008-10-01

We report on astrometric observations of H2O masers around the red supergiant VY Canis Majoris carried out with VLBI Exploration of Radio Astrometry (VERA). Based on astrometric monitoring for 13 months, we successfully measured a trigonometric parallax of 0.88±0.08 mas, corresponding to a distance of 1.14+0.11-0.09kpc. This is the most accurate determined distance to VY CMa and the first one based on an annual parallax measurement. The luminosity of VY CMa has been overestimated due to a previously accepted distance. With our result, we re-estimated the luminosity of VY CMa to be (3±0.5) × 105Lodot using the bolometric flux integrated over optical and IR wavelengths. This improved luminosity value makes the location of VY CMa on the Hertzsprung-Russell (HR) diagram much closer to the theoretically allowable zone (i.e. the left side of the Hayashi track) than previous ones, though the uncertainty in the effective temperature of the stellar surface still does not permit us to make a final conclusion.

Molecular Abundances in the Circumstellar Envelope of Oxygen-Rich Supergiant VY Canis Majoris

NASA Astrophysics Data System (ADS)

Edwards, Jessica L.; Ziurys, Lucy

2014-06-01

A complete set of molecular abundances have been established for the Oxygen-rich circumstellar envelope (CSE) surrounding the supergiant star VY Canis Majoris (VY CMa). These data were obtained from The Arizona Radio Observatory (ARO) 1-mm spectral line survey of this object using the ARO Sub-millimeter Telescope (SMT), as well as complimentary transitions taken with the ARO 12-meter. The non-LTE radiative transfer code ESCAPADE has been used to obtain the molecular abundances and distributions in VY CMa, including modeling of the various asymmetric outflow geometries in this source. For example, SO and SO2 were determined to arise from five distinct outflows, four of which are asymmetric with respect to the central star. Abundances of these two sulfur-bearing molecules range from 3 x 10-8 - 2.5 x 10-7 for the various outflows. Similar results will be presented for molecules like CS, SiS, HCN, and SiO, as well as more exotic species like NS, PO, AlO, and AlOH. The molecular abundances between the various outflows will be compared and implications for supergiant chemistry will be discussed.

The Disk and Jet of the Classical T Tauri Star AA Tau

NASA Technical Reports Server (NTRS)

Cox, A. W.; Grady, C. A.; Hamel, H.; Hornbeck, Jeremy; Russell, R.; Sitko, M.; Woodgate, B.

2013-01-01

Previous studies of the classical T Tauri star AA Tau have interpreted the UX Orionis-like photopolarimetric variability as being due to a warp in the inner disk caused by an inclined stellar magnetic dipolefield. We test that these effects are macroscopically observable in the inclination and alignment of the disk. We use the HST/STIS coronagraphic detection of the disk to measure the outer disk radius and inclination, and find that the inner disk is both misinclined and misaligned with respect to the outer disk. AA Tau drives a faint jet which is also misaligned with respect to the projection of the outer disk minor axis. The jet is also poorly collimated near the star. The measured inclination, 71+/-1deg, is above the inclination range suggested for stars with UX Orionis-like variability, indicating that dust grains in the disk have grown and settled toward the disk midplane.

Representation of potential information gain to measure the price of anarchy on ISR activities

NASA Astrophysics Data System (ADS)

Ortiz-Peña, Hector J.; Hirsch, Michael; Karwan, Mark; Nagi, Rakesh; Sudit, Moises

2013-05-01

One of the main technical challenges facing intelligence analysts today is effectively determining information gaps from huge amounts of collected data. Moreover, getting the right information to/from the right person (e.g., analyst, warfighter on the edge) at the right time in a distributed environment has been elusive to our military forces. Synchronization of Intelligence, Surveillance, and Reconnaissance (ISR) activities to maximize the efficient utilization of limited resources (both in quantity and capabilities) has become critically important to increase the accuracy and timeliness of overall information gain. Given this reality, we are interested in quantifying the degradation of solution quality (i.e., information gain) as a centralized system synchronizing ISR activities (from information gap identification to information collection and dissemination) moves to a more decentralized framework. This evaluation extends the concept of price of anarchy, a measure of the inefficiency of a system when agents maximize decisions without coordination, by considering different levels of decentralization. Our initial research representing the potential information gain in geospatial and time discretized spaces is presented. This potential information gain map can represent a consolidation of Intelligence Preparation of the Battlefield products as input to automated ISR synchronization tools. Using the coordination of unmanned vehicles (UxVs) as an example, we developed a mathematical programming model for multi-perspective optimization in which each UxV develops its own fight plan to support mission objectives based only on its perspective of the environment (i.e., potential information gain map). Information is only exchanged when UxVs are part of the same communication network.

3.3 CM JVLA OBSERVATIONS OF TRANSITIONAL DISKS: SEARCHING FOR CENTIMETER PEBBLES

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

Zapata, Luis A.; Rodríguez, Luis F.; Palau, Aina, E-mail: lzapata@crya.unam.mx

We present sensitive (rms-noises ∼4–25 μ Jy) and high angular resolution (∼1″–2″) 8.9 GHz (3.3 cm) Karl G. Jansky Very Large Array radio continuum observations of 10 presumed transitional disks associated with young low-mass stars. We report the detection of radio continuum emission in 5 out of the 10 objects (RXJ1615, UX Tau A, LkCa15, RXJ1633, and SR 24s). In the case of LkCa15, the centimeter emission is extended, and has a similar morphology to that of the transitional disk observed at millimeter wavelengths with an inner depression. For these five detections, we construct the spectral energy distributions from themore » centimeter to submillimeter wavelengths, and find that they can be well fitted with a single (RXJ1633 and UX Tau A) or a two-component power law (LkCa15, RXJ1615, and SR 24s). For the cases where a single power law fits the data well, the centimeter emission is likely produced by optically thin dust with large grains (i.e., centimeter-size pebbles) present in the transitional disks. For the cases where a double power law fits the data, the centimeter emission might be produced by the combination of photoevaporation and a free–free jet. We conclude that RXJ1633 and UX Tau A are excellent examples of transitional disks where the structure of the emission from centimeter/millimeter pebbles can be studied. In the other cases, some other physical emitting mechanisms are also important in the centimeter regime.« less

3.3 CM JVLA Observations of Transitional Disks: Searching for Centimeter Pebbles

NASA Astrophysics Data System (ADS)

Zapata, Luis A.; Rodríguez, Luis F.; Palau, Aina

2017-01-01

We present sensitive (rms-noises ˜4-25 μJy) and high angular resolution (˜1″-2″) 8.9 GHz (3.3 cm) Karl G. Jansky Very Large Array radio continuum observations of 10 presumed transitional disks associated with young low-mass stars. We report the detection of radio continuum emission in 5 out of the 10 objects (RXJ1615, UX Tau A, LkCa15, RXJ1633, and SR 24s). In the case of LkCa15, the centimeter emission is extended, and has a similar morphology to that of the transitional disk observed at millimeter wavelengths with an inner depression. For these five detections, we construct the spectral energy distributions from the centimeter to submillimeter wavelengths, and find that they can be well fitted with a single (RXJ1633 and UX Tau A) or a two-component power law (LkCa15, RXJ1615, and SR 24s). For the cases where a single power law fits the data well, the centimeter emission is likely produced by optically thin dust with large grains (I.e., centimeter-size pebbles) present in the transitional disks. For the cases where a double power law fits the data, the centimeter emission might be produced by the combination of photoevaporation and a free-free jet. We conclude that RXJ1633 and UX Tau A are excellent examples of transitional disks where the structure of the emission from centimeter/millimeter pebbles can be studied. In the other cases, some other physical emitting mechanisms are also important in the centimeter regime.

Description and Features of UX-Analyze

DTIC Science & Technology

2009-02-01

POB model and GUI for EM63 Inversion The full Pasion -Oldenburg-Billings (POB) analysis assumes an axially symmetric (axial and transverse) tensor...output from the EM63 inversion. 1 Pasion , L.R., and Oldenburg, D.W., 2001, Locating and

Examples of Mass Wasting and Hemipelagic Sedimentation of Brazos-Trinity Basin #4 and Ursa Basin, Northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Schneider, J.; Moerz, T.; Bartetzko, A.; Iturrino, G. J.; Edeskar, T. M.; Flemings, P. B.; Behrmann, J. H.; John, C. M.

2005-12-01

Pleistocene sea level changes influenced the sedimentation history on the passive continental margin of the northern Gulf of Mexico coast. During IODP Expedition 308, the Brazos-Trinity #4 and Ursa Basin were drilled to study -overpressure, fluid flow and deformation processes in a passive margin setting. The Brazos-Trinity Basin #4 is located 200 km south of Galveston, Texas (USA) in ~1400 m water depth below an extended shelf section. Ursa Basin is located 150 km south of New Orleans, Louisiana (USA) in ~1000 m water depth south of the Mississippi river mouth. Despite their similar geotectonic setting both basins show fundamental differences in their style of mass wasting and drape sedimentation. Here we use core descriptions, core photographs, Formation MicroScanner (FMS) data and selected physical properties measurements (magnetic susceptibility, GRAPE density) to illustrate and compare styles of mass wasting and drape sedimentation on selected intervals for the first 4 Marine Isotope Stages. Special emphasis is given to the thickness and frequency of single depositional events. One aim is to estimate the mass wasting / hemipelagic accumulation ratio for both basins and compare it to the average sedimentation rates based on the preliminary shipboard age models. This information will be used in the future to study how sedimentation processes control permeability and pore pressure. In this upcoming project, starting in mid 2006, will use well-logging data to compute continuous porosity, permeability, and pore pressure profiles. These computations require input and reference data obtained from petrophysical and geotechnical core analyses and in situ measurements (e.g. matrix density to calculate porosity from the density log, permeability and porosity to derive porosity-permeability relations, effective stress to calculate pore pressure). Permeability and effective stress will be measured using oedometer tests on undisturbed samples. The detailed lithostratigraphic information, particularly turbidite thickness, and the permeability and pore pressure profiles will be used as input data for one-dimensional modeling of the compression history of two Sites using the civil engineering modeling software PLAXIS.

The 1 mm spectrum of VY Canis Majoris: Chemistry in an O-rich envelope

NASA Astrophysics Data System (ADS)

Tenenbaum, Emily D.; Milam, Stefanie N.; Apponi, Aldo J.; Woolf, Neville J.; Ziurys, Lucy M.; Schöier, Fredrik L.

2008-10-01

We present preliminary results of an unbiased spectral survey at 1 mm of the oxygen-rich supergiant, VY CMa. A number of exotic molecules have been detected, including NaCl and PO, and a relatively rich organic chemistry is observed. Results of the survey will be compared with carbon-rich stars.

Galactic water vapor emission: further observations of variability.

PubMed

Knowles, S H; Mayer, C H; Sullivan, W T; Cheung, A C

1969-10-10

Recent observations of the 1.35-centimeter line emission of water vapor from galactic sources show short-term variability in the spectra of several sources. Two additional sources, Cygnus 1 and NGC 6334N, have been observed, and the spectra of W49 and VY Canis Majoris were measured over a wider range of radial velocity.

On the modified intermediate long-wave equation

NASA Astrophysics Data System (ADS)

Naumkin, Pavel I.; Sánchez-Suárez, Isahi

2018-03-01

We consider the modified intermediate long-wave equation ut-∂xu3+1ϑux+VP∫R12ϑcoth(π(y-x)2ϑ)uyy(t,y)dy=0. We develop the factorization technique to study the large time asymptotics of solutions.

THE DENSITY OF MID-SIZED KUIPER BELT OBJECT 2002 UX25 AND THE FORMATION OF THE DWARF PLANETS

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

Brown, M. E., E-mail: mbrown@caltech.edu

The formation of the largest objects in the Kuiper belt, with measured densities of ∼1.5 g cm{sup –3} and higher, from the coagulation of small bodies, with measured densities below 1 g cm{sup –3}, is difficult to explain without invoking significant porosity in the smallest objects. If such porosity does occur, measured densities should begin to increase at the size at which significant porosity is no longer supported. Among the asteroids, this transition occurs for diameters larger than ∼350 km. In the Kuiper belt, no density measurements have been made between ∼350 km and ∼850 km, the diameter range where porosities might first begin tomore » drop. Objects in this range could provide key tests of the rock fraction of small Kuiper belt objects (KBOs). Here we report the orbital characterization, mass, and density determination of the 2002 UX25 system in the Kuiper belt. For this object, with a diameter of ∼650 km, we find a density of 0.82 ± 0.11 g cm{sup –3}, making it the largest solid known object in the solar system with a measured density below that of pure water ice. We argue that the porosity of this object is unlikely to be above ∼20%, suggesting a low rock fraction. If the currently measured densities of KBOs are a fair representation of the sample as a whole, creating ∼1000 km and larger KBOs with rock mass fractions of 70% and higher from coagulation of small objects with rock fractions as low as those inferred from 2002 UX25 is difficult.« less

Inducible Nitric Oxide Inhibitors Block NMDA Antagonist-Stimulated Motoric Behaviors and Medial Prefrontal Cortical Glutamate Efflux

PubMed Central

Bergstrom, Hadley C.; Darvesh, Altaf S.; Berger, S. P.

2015-01-01

Nitric oxide (NO) plays a critical role in the motoric and glutamate releasing action of N-methyl-D-aspartate (NMDA)-antagonist stimulants. Earlier studies utilized neuronal nitric oxide synthase inhibitors (nNOS) for studying the neurobehavioral effects of non-competitive NMDA-antagonist stimulants such as dizocilpine (MK-801) and phencyclidine (PCP). This study explores the role of the inducible nitric oxide synthase inhibitors (iNOS) aminoguanidine (AG) and (-)-epigallocatechin-3-gallate (EGCG) in NMDA-antagonist induced motoric behavior and prefrontal cortical glutamate efflux. Adult male rats were administered a dose range of AG, EGCG, or vehicle prior to receiving NMDA antagonists MK-801, PCP, or a conventional psychostimulant (cocaine) and tested for motoric behavior in an open arena. Glutamate in the medial prefrontal cortex (mPFC) was measured using in vivo microdialysis after a combination of AG or EGCG prior to MK-801. Acute administration of AG or EGCG dose-dependently attenuated the locomotor and ataxic properties of MK-801 and PCP. Both AG and EGCG were unable to block the motoric effects of cocaine, indicating the acute pharmacologic action of AG and EGCG is specific to NMDA antagonism and not generalizable to all stimulant class drugs. AG and EGCG normalized MK-801-stimulated mPFC glutamate efflux. These data demonstrate that AG and EGCG attenuates NMDA antagonist-stimulated motoric behavior and cortical glutamate efflux. Our results suggest that EGCG-like polyphenol nutraceuticals (contained in “green tea” and chocolate) may be clinically useful in protecting against the adverse behavioral dissociative and cortical glutamate stimulating effects of NMDA antagonists. Medications that interfere with NMDA antagonists such as MK-801 and PCP have been proposed as treatments for schizophrenia. PMID:26696891

Spatial heterodyne interferometry of VY Canis Major's, alpha Orionis, alpha Scorpii, and R leonis at 11 microns

NASA Technical Reports Server (NTRS)

Sutton, E. C.; Storey, J. W. V.; Betz, A. L.; Townes, C. H.; Spears, D. L.

1977-01-01

Using the technique of heterodyne interferometry, measurements were made of the spatial distribution of 11 micron radiation from four late type stars. The circumstellar shells surrounding VY Canis Majoris, alpha Orionis, and alpha Scorpii were resolved, whereas that of R Leonis was only partially resolved at a fringe spacing of 0.4 sec.

VY Canis Majoris: The Astrophysical Basis of Its Luminosity

NASA Astrophysics Data System (ADS)

Gehrz, Robert D.; Humphreys, R. M.; Jones, T. J.

2006-12-01

The luminosity of the famous red supergiant VY CMa ( L = 4 5 x 105 L ) is well-determined from its spectral energy distribution and distance, and places it near the empirical upper luminosity limit for cool hypergiants. In contrast, its surface temperature is fundamentally ill-defined. Implications for its location on the HR Diagram and its apparent size are discussed.

Interferometric Observation of the Highly Polarized SiO Maser Emission from the v = 1, J = 5-4 Transition Associated with VY Canis Majoris

NASA Astrophysics Data System (ADS)

Shinnaga, Hiroko; Moran, James M.; Young, Ken H.; Ho, Paul T. P.

2004-11-01

We used the Submillimeter Array to image the SiO maser emission in the v=1, J=5-4 transition associated with the peculiar red supergiant VY Canis Majoris. We identified seven maser components and measured their relative positions and linear polarization properties. Five of the maser components are coincident to within about 150 mas (~200 AU at the distance of 1.5 kpc); most of them may originate in the circumstellar envelope at a radius of about 50 mas from the star along with the SiO masers in the lowest rotational transitions. Our measurements show that two of the maser components may be offset from the inner stellar envelope (at the 3 σ level of significance) and may be part of a larger bipolar outflow associated with VY CMa identified by Shinnaga et al. The strongest maser feature at a velocity of 35.9 km s-1 has a 60% linear polarization, and its polarization direction is aligned with the bipolar axis. Such a high degree of polarization suggests that maser inversion is due to radiative pumping. Five of the other maser features have significant linear polarization.

Radio Interferometric Detection of TiO and TiO_2 in VY Canis Majoris: "seeds" of Inorganic Dust Formation

NASA Astrophysics Data System (ADS)

Brunken, S.; Muller, H. S. P.; Kaminski, T.; Menten, K. M.; Gott-Lieb, C. A.; Patel, N. A.; Young, K. H.; McCarthy, M. C.; Winters, J. M.; Decin, L.

2013-06-01

Circumstellar envelopes around late-type stars harbour a rich variety of molecular gas and copious amounts of dust, originating from the mass-loss of the central star during the asymptotic giant branch (AGB) or the red supergiant phase. The formation of dust in these objects, in particular the first nucleation stages out of gas phase molecules, is still poorly understood. Here we report the first detection of pure rotational transitions of the two simplest titanium oxides, TiO and TiO_2, towards the oxygen-rich red supergiant VY Canis Majoris (VY CMa). This actually represents the first secure identification of TiO_2 in space. Observations of several rotational emission lines of both species with the Submillimeter Array (SMA) in the 345 GHz-band and with the IRAM Plateau de Bure Interferometer (PdBI) around 220 GHz confirm the presence of these refractory species in the cool (<1000 K) circumstellar envelope in a region several times the size of the dust formation zone. The role of Ti oxides as "seeds" of inorganic dust formation in oxygen-rich circumstellar envelopes will be discussed in view of the present observations.

ESTCP Cost and Performance Report (UX-9909)

DTIC Science & Technology

2006-06-01

watts per square centimeter vii ACKNOWLEDGEMENTS We would like to express appreciation to John Schiavone of Sparta Inc, for his efforts...navsea.navy.mil Project Manager John Schiavone Sparta, Inc. 6000 Technology Drive, Building 3 Huntsville, AL 35805 (256) 837-5282, Ext. 2416 (256) 890

A Sex Chromosome piRNA Promotes Robust Dosage Compensation and Sex Determination in C. elegans.

PubMed

Tang, Wen; Seth, Meetu; Tu, Shikui; Shen, En-Zhi; Li, Qian; Shirayama, Masaki; Weng, Zhiping; Mello, Craig C

2018-03-26

In metazoans, Piwi-related Argonaute proteins engage piRNAs (Piwi-interacting small RNAs) to defend the genome against invasive nucleic acids, such as transposable elements. Yet many organisms-including worms and humans-express thousands of piRNAs that do not target transposons, suggesting that piRNA function extends beyond genome defense. Here, we show that the X chromosome-derived piRNA 21ux-1 downregulates XOL-1 (XO Lethal), a master regulator of X chromosome dosage compensation and sex determination in Caenorhabditis elegans. Mutations in 21ux-1 and several Piwi-pathway components sensitize hermaphrodites to dosage compensation and sex determination defects. We show that the piRNA pathway also targets xol-1 in C. briggsae, a nematode species related to C. elegans. Our findings reveal physiologically important piRNA-mRNA interactions, raising the possibility that piRNAs function broadly to ensure robust gene expression and germline development. Copyright © 2018. Published by Elsevier Inc.

Vorticity and helicity decompositions and dynamics with real Schur form of the velocity gradient

NASA Astrophysics Data System (ADS)

Zhu, Jian-Zhou

2018-03-01

The real Schur form (RSF) of a generic velocity gradient field ∇u is exploited to expose the structures of flows, in particular, our field decomposition resulting in two vorticities with only mutual linkage as the topological content of the global helicity (accordingly decomposed into two equal parts). The local transformation to the RSF may indicate alternative (co)rotating frame(s) for specifying the objective argument(s) of the constitutive equation. When ∇u is uniformly of RSF in a fixed Cartesian coordinate frame, i.e., ux = ux(x, y) and uy = uy(x, y), but uz = uz(x, y, z), the model, with the decomposed vorticities both frozen-in to u, is for two-component-two-dimensional-coupled-with-one-component-three-dimensional flows in between two-dimensional-three-component (2D3C) and fully three-dimensional-three-component ones and may help curing the pathology in the helical 2D3C absolute equilibrium, making the latter effectively work in more realistic situations.

A space weather forecasting system with multiple satellites based on a self-recognizing network.

PubMed

Tokumitsu, Masahiro; Ishida, Yoshiteru

2014-05-05

This paper proposes a space weather forecasting system at geostationary orbit for high-energy electron flux (>2 MeV). The forecasting model involves multiple sensors on multiple satellites. The sensors interconnect and evaluate each other to predict future conditions at geostationary orbit. The proposed forecasting model is constructed using a dynamic relational network for sensor diagnosis and event monitoring. The sensors of the proposed model are located at different positions in space. The satellites for solar monitoring equip with monitoring devices for the interplanetary magnetic field and solar wind speed. The satellites orbit near the Earth monitoring high-energy electron flux. We investigate forecasting for typical two examples by comparing the performance of two models with different numbers of sensors. We demonstrate the prediction by the proposed model against coronal mass ejections and a coronal hole. This paper aims to investigate a possibility of space weather forecasting based on the satellite network with in-situ sensing.

Reconstruction of the accretion disk in six cataclysmic variable stars

NASA Astrophysics Data System (ADS)

Rutten, R. G. M.; van Paradijs, J.; Tinbergen, J.

1992-07-01

The maximum-entropy eclipse-mapping algorithm is used to reconstruct images of the accretion disks of the novalike variable stars RW Tri, UX UMa, SW Sex, LX Ser, V 1315 Aql, and V363 Aur. The 2D disk intensity maps deduced from the light curves reveal the size of the disk and its radial intensity dependence. Black-body temperature maps deduced from the intensity maps at different wavelengths show that the disks in RW Tri, UX UMa, and V363 Aur have a radial temperature dependence which closely matches the fundamental theoretical run of the effective temperature with radial distance from disk center: T(eff) varies as R exp -3/4. The system V1315 Aql and SW Sex exhibit a much flatter run of T(R) in the inner region of the disk, while LX Ser appears to hold a position in between these two extremes. The consequences of these results for accretion disk models are also discussed.

Sky Luminaries in the Space Orienting Activity of Homo Sapiens in the Middle Palaeolithic

NASA Astrophysics Data System (ADS)

Kaurov, E. N.

Data describing the beginnings of the space orienting activity of Homo sapiens is analysed and systematized: observation of the Pole and the recognition of Ursa Major were used as the basis of the determination of the points of the compass. Data and results from astronomy, history of astronomy, archaeology and palaeoanthropology were used for the reconstruction of the evolution of the space orienting activity of Homo sapiens.

VizieR Online Data Catalog: Carbon in red giants in GCs and dSph galaxies (Kirby+, 2015)

NASA Astrophysics Data System (ADS)

Kirby, E. N.; Guo, M.; Zhang, A. J.; Deng, M.; Cohen, J. G.; Guhathakurta, P.; Shetrone, M. D.; Lee, Y. S.; Rizzi, L.

2015-07-01

We obtained Keck/DEIMOS spectra of the carbon G band in red giants in Milky Way (MW) globular clusters (GCs) and dwarf spheroidal galaxies (dSphs) between 2011 Jul 29 and 2012 Mar 19. The GCs are NGC 2419, NGC 4590 (M68), and NGC 7078 (M15). The dSphs are Sculptor, Fornax, Ursa Minor, and Draco. See table 1. (3 data files).

The Spectrum of VY Canis Majoris in 2000 February

NASA Astrophysics Data System (ADS)

Wallerstein, George; Gonzalez, Guillermo

2001-08-01

We present the current (2000 February) status of the optical spectrum of the irregularly variable M supergiant VY CMa, based on high-resolution CCD spectra. The emission spectrum is largely unchanged over the past 43 yr, with low-lying atomic lines as well as the molecules TiO and ScO in emission. Tables of observed wavelengths for both identified and unidentified lines are presented.

An Open-label Phase 2 Study of UX007 (Triheptanoin) in Subjects With Long-Chain Fatty Acid Oxidation Disorders (LC-FAOD)

ClinicalTrials.gov

2018-06-01

Long-chain Fatty Acid Oxidation Disorders (LC-FAOD); Carnitine Palmitoyltransferase (CPT II) Deficiency; Very Long Chain Acyl-CoA Dehydrogenase (VLCAD) Deficiency; Longchain 3-hydroxy-acyl-CoA Dehydrogenase (LCHAD) Deficiency; Trifunctional Protein (TFP) Deficiency

MONARCH: A Morphable Networked micro-ARCHitecture

DTIC Science & Technology

2002-09-01

USC INFORMATION INSTITUTE Principal Investigator John Granacki RESEARCH STAFF Jeff Draper Pedro Diniz Jeff LaCoss Co-Principal Investigator Michael...representative applications MONARCH Processing Card - 6Ux160 double euro card form factor - B ac kp la n e In te rc o n n ec t MONARCH chip EDGE MEMORY

VizieR Online Data Catalog: Photometry and spectroscopy of NP Per (Lacy+, 2016)

NASA Astrophysics Data System (ADS)

Lacy, C. H. S.; Fekel, F. C.; Pavlovski, K.; Torres, G.; Muterspaugh, M. W.

2016-09-01

From 2011 November through 2014 November, we acquired 56 high-quality spectra of NP Per with the Tennessee State University 2m Automatic Spectroscopic Telescope (AST) and a fiber-fed echelle spectrograph at Fairborn Observatory in southeast Arizona. Of these spectra, 55 were suitable for radial velocity measurements (see Table1). The detector for these observations was a Fairchild 486 CCD, having 4096*4096 15μ pixels. While the spectrograms have 48 orders ranging from 3800 to 8260Å, we have used just the orders that cover the wavelength region from 4920 to 7100Å. We made our observations with a fiber that produced a spectral resolution of 0.4Å, corresponding to a resolving power of 15000 at 6000Å. Our spectra have typical signal-to-noise ratios (S/Ns) of 40 at 6000Å. We began V-band photometric observations of NP Per with the URSA WebScope on 2003 December 2. URSA is a 10inch Schmidt-Cassegrain telescope made by Meade Instruments Corp., equipped with a V-band filter and a Santa Barbara Instruments Group ST8 CCD camera, housed in a Technical Innovations RoboDome, all controlled by a Macintosh computer in a control room under the observing deck of Kimpel Hall on the University of Arkansas campus at Fayetteville. A larger telescope, the NFO WebScope, was brought to bear on 2005 February 27. Nearly all the observations after this date were obtained with the NFO, which is a robotic 24inch Cassegrain reflector located near Silver City, NM, USA. Both telescopes used Bessel V filters consisting of 2.0mm of GG495 and 3.0mm of BG 39. Exposures were 120 seconds long for both telescopes, and the cadence was typically 150 seconds per image. The images contained the variable star (TYC 2371-0390-1=BD +31 0729) and 2 comparison stars (TYC 2371-156-1 and TYC 2371-1034-1) of approximately the same brightness and color as the variable star. The observations are given in Table6 for the URSA WebScope and in Table7 for the NFO WebScope. Dates of eclipses obtained from the literature are given in Table8. (6 data files).

Value of Hipparcos Catalogue shown by planet assessments

NASA Astrophysics Data System (ADS)

1996-08-01

The first detailed findings from Hipparcos, recently published in Astronomy and Astrophysics Letters, confirm the existence of planets around other stars. Hipparcos astronomers plucked out their data on three stars suspected of possessing attendant planets. Their distances, measured far more accurately than ever before, enables the astronomers to rule out, in two cases, the possibility that the supposed planets might be small stars. The discovery of alien planets in the first astronomical step towards fashioning a proper science out of the speculations about life beyond the solar system. Hipparcos makes a decisive contribution by setting an upper limit to their masses. Astronomers at the Geneva Observatory caused a sensation last year when they reported slight motions in the star 51 Pegasi, due to a massive planet orbiting around it. With a ground-based telescope they detected small shifts in the wavelength of light as 51 Pegasi moved slowly under the influence of its invisible companion. This year, astronomers at San Francisco State University confirmed the discovery and have subsequently reported two similar cases, in the stars 47 Ursae Majoris and 70 Virginis. Uncertainties about the orientation of the planets' orbits and the distances of the stars left a wide margin of doubt about the masses of the candidate planets. Accurate rangefinding by Hipparcos puts the star 47 Ursae Majoris at a distance of 46 light-years. Calculations then set an upper limit on the mass of the companion at 7 to 22 times the mass of Jupiter, the Sun's largest planet. The Sun itself is a thousand times more massive that Jupiter, and theorists believe that the smallest true star would have a mass of 80 Jupiters. Below that mass, the object cannot burn hydrogen in the nuclear fashion, which is the most characteristic source of energy for stars. In the range between 17 and 80 Jupiter masses an object is called a brown dwarf. It can in theory derive a little energy by burning heavy hydrogen, or deuterium. Even the "worst-case" mass quoted here for the companion of 47 Ursae Majoris, 22 Jupiter masses, is only a maximum, not a measurement. So the companion is almost certainly a true planet with less than 17 times the mass of Jupiter. For the star 70 Virginis, the distance newly established by Hipparcos is 59 light-years. Even on the least favourable assumptions about its orbit, the companion cannot have more than 65 Jupiter masses. It could be brown dwarf rather than a planet, but not a true star. Much more ambiguous is the result for 51 Pegasi. Its distance is 50 light-years and theoretically the companion could have more than 500 Jupiter masses, or half the mass of the Sun. This is a peculiar case anyway, because the companion is very close to 51 Pegasi. Small planets of the size of the Earth might be more promising as abodes of life than the large planets detectable by present astronomical methods. Space scientists are now reviewing methods of detecting the presence of life on alien planets by detecting the infrared signature of ozone in a planet's atmosphere. Ozone is a by-product of oxygen gas, which in turn is supposed to be generated only by life similar to that on the Earth. Meanwhile the detection of planets of whatever size is a tour de force for astronomers, and by analogy with the Solar System one may suppose that large planets are often likely to be accompanied by smaller ones. "Hipparcos was not conceived to look for planets," comments Michael Perryman, ESA's project scientist for Hipparcos, "and this example of assistance to our fellow-astronomers involves a very small sample of our measurements. But it is a timely result when we are considering planet-hunting missions for the 21st Century. The possibilities include a super-Hipparcos that could detect directly the wobbles in nearby stars due to the presence of planets." Hipparcos Catalogue ready for use The result from Hipparcos on alien planets coincides with the completion of the Hipparcos Catalogue and the distribution of the data to collaborating scientists. The Catalogue lists the positions, distances, motions and brightnesses of 118,000 stars, within a self-consistent framework for the whole sky. The results include remarkable detail on the orbits of double stars and the changing light output of variable stars. Thanks to the unprecedented accuracy of space observations with a specially conceived satellite, the Hipparcos Catalogue gives positions of the stars to much better than a millionth of a degree. This is over one hundred times more accurate than the most careful fixes of stars from observatories on the ground. With the Catalogue's completion, the Hipparcos mission achieves its purpose of revolutionizing astrometry, the positional science that has underpinned mankind's studies of the Universe since the satellite's namesake Hipparchus the Greek surveyed the sky in the 2nd Century BC. Another pioneer of astrometry was Tycho the Dane (16th Century AD) and he is commemorated in a second product of the Hipparcos mission. The Tycho Catalogue, which is nearing completion, lists a far larger number of stars, slightly more than a million. Their positions will be less precise than in the Hipparcos Catalogue, but still far better than the ground-based results, and will include valuable data on the colours of stars. The first chance to cull discoveries from the Hipparcos data resides with the teams in nine European countries who have laboured to achieve this breakthrough in astronomy. For some team members the effort goes back thirty years, to the first proposal of an astrometric satellite in France in 1966. ESA approved the mission in 1980 and Hipparcos was launched in August 1989. Despite finding itself in the wrong orbit, Hipparcos operated successfully until March 1993. Three more years have gone into data analysis, using computers in a dozen institutes across Europe for the most elaborate calculations in the history of astronomy. Members of the teams will now have privileged use of the data for nearly a year, before the release of the catalogues to the world-wide astronomical community in April 1997. The new precision in star-fixing promises an extraordinary harvest of new results, on subjects ranging from asteroids to cosmology. A vivid picture of the stars in motion in our corner of the Milky Way Galaxy is one expected outcome. Hipparcos has more than doubled the number of known variable stars, and has discovered many thousands of new double or multiple star systems. Striding the light-years by parallax The study of stars with candidate planets is a dramatic example of Hipparcos's new determinations of the distances of stars by the parallax principle. Many other discoveries will flow from it. Parallax is an unfamiliar name for a familiar concept, akin to stereoscopic vision. People judge distances in nearby scenes from the difference in direction of the two eyes when focused on an object. Military rangefinders use the same principle, with more widely separated optics. Astronomers adapt the Earth's orbit to make a huge rangefinder. At opposite seasons, the Earth is on opposite sides of the Sun, at vantage points 300 million kilometres apart. As a result, the bearings of stars change a little. Nearby stars shift more than very distant stars, and astronomers can measure their distances by trigonometry. Until now, unavoidable inaccuracies in observing the directions of stars from the ground have meant that the distances of only the closest stars can be measured directly by parallax, out to about 100 light-years. Even at short ranges the margin of uncertainty is often wide. Long chains of inference and observation extend the distance scale to much farther objects, including galaxies millions or billions of light-years away. From the resulting estimates, astronomers try to calculate the age of the Universe and arrive at conclusions about its origin and evolution. The foundation for these reckonings has been decidedly shaky. By measuring seasonal changes of direction to an accuracy of better than a millionth of degree, the Hipparcos mission has taken a great stride across the light-years and transformed the art of determining astronomical distances. Hipparcos has pushed the practical range of direct and accurate distance measurement out to about 1000 light-years. That means rangefinding for a thousand times as many stars as before. As for the nearer stars, parallax measurements of their distances are now far more accurate, thanks to Hipparcos. The star 70 Virginis, which figures in the planets study, illustrates the overwhelming power of the new data. Ground-based measurements of the shift in its position were wildly discrepant. The largest reported distance, 102 light-years, was more than three times the smallest, 29 light-years. By contrast, the uncertainty in the actual distance of 59.1 light-years, measured by Hipparcos, has been whittled down to about one per cent, or roughly half a light-year. Please note that as from 1 August 1996 you can access the ESA Space Science Newsletter on Internet, either via the home page : http://www.esrin.esa.it or directly on : http://www.estec.esa.nl/spdwww/h2000/html/snlmain.htm

The evolution of the lithium abundances of solar-type stars. II - The Ursa Major Group

NASA Technical Reports Server (NTRS)

Soderblom, David R.; Pilachowski, Catherine A.; Fedele, Stephen B.; Jones, Burton F.

1993-01-01

We draw upon a recent study of the membership of the Ursa Major Group (UMaG) to examine lithium among 0.3 Gyr old solar-type stars. For most G and K dwarfs, Li confirms the conclusions about membership in UMaG reached on the basis of kinematics and chromospheric activity. G and K dwarfs in UMaG have less Li than comparable stars in the Pleiades. This indicates that G and K dwarfs undergo Li depletion while they are on the main sequence, in addition to any pre-main-sequence depletion they may have experienced. Moreover, the Li abundances of the Pleiades K dwarfs cannot be attributed to main-sequence depletion alone, demonstrating that pre-main-sequence depletion of Li also takes place. The sun's Li abundance implies that the main-sequence mechanism becomes less effective with age. The hottest stars in UMaG have Li abundances like those of hot stars in the Pleiades and Hyades and in T Tauris, and the two genuine UMaG members with temperatures near Boesgaard's Li chasm have Li abundances consistent with that chasm developing fully by 0.3 Gyr for stars with UMaG's metallicity. We see differences in the abundance of Li between UMaG members of the same spectral types, indicating that a real spread in the lithium abundance exists within this group.

Retrogressive failures recorded in mass transport deposits in the Ursa Basin, Northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Sawyer, Derek E.; Flemings, Peter B.; Dugan, Brandon; Germaine, John T.

2009-10-01

Clay-rich mass transport deposits (MTDs) in the Ursa Basin, Gulf of Mexico, record failures that mobilized along extensional failure planes and transformed into long runout flows. Failure proceeded retrogressively: scarp formation unloaded adjacent sediment causing extensional failure that drove successive scarp formation updip. This model is developed from three-dimensional seismic reflection data, core and log data from Integrated Ocean Drilling Project (IODP) Expedition 308, and triaxial shear experiments. MTDs are imaged seismically as low-amplitude zones above continuous, grooved, high-amplitude basal reflections and are characterized by two seismic facies. A Chaotic facies typifies the downdip interior, and a Discontinuous Stratified facies typifies the headwalls/sidewalls. The Chaotic facies contains discontinuous, high-amplitude reflections that correspond to flow-like features in amplitude maps: it has higher bulk density, resistivity, and shear strength, than bounding sediment. In contrast, the Discontinuous Stratified facies contains relatively dim reflections that abut against intact pinnacles of parallel-stratified reflections: it has only slightly higher bulk density, resistivity, and shear strength than bounding sediment, and deformation is limited. In both facies, densification is greatest at the base, resulting in a strong basal reflection. Undrained shear tests document strain weakening (sensitivity = 3). We estimate that failure at 30 meters below seafloor will occur when overpressure = 70% of the hydrostatic effective stress: under these conditions soil will liquefy and result in long runout flows.

Temporal Data Fusion Approaches to Remote Sensing-Based Wetland Classification

NASA Astrophysics Data System (ADS)

Montgomery, Joshua S. M.

This thesis investigates the ecology of wetlands and associated classification in prairie and boreal environments of Alberta, Canada, using remote sensing technology to enhance classification of wetlands in the province. Objectives of the thesis are divided into two case studies, 1) examining how satellite borne Synthetic Aperture Radar (SAR), optical (RapidEye & SPOT) can be used to evaluate surface water trends in a prairie pothole environment (Shepard Slough); and 2) investigating a data fusion methodology combining SAR, optical and Lidar data to characterize wetland vegetation and surface water attributes in a boreal environment (Utikuma Regional Study Area (URSA)). Surface water extent and hydroperiod products were derived from SAR data, and validated using optical imagery with high accuracies (76-97% overall) for both case studies. High resolution Lidar Digital Elevation Models (DEM), Digital Surface Models (DSM), and Canopy Height Model (CHM) products provided the means for data fusion to extract riparian vegetation communities and surface water; producing model accuracies of (R2 0.90) for URSA, and RMSE of 0.2m to 0.7m at Shepard Slough when compared to field and optical validation data. Integration of Alberta and Canadian wetland classifications systems used to classify and determine economic value of wetlands into the methodology produced thematic maps relevant for policy and decision makers for potential wetland monitoring and policy development.

Connecting American Manufacturers (CAM) Virtual Manufacturing Marketplace (VMM)

DTIC Science & Technology

2013-11-01

88ABW-2013-5037 1.0 SUMMARY The Connecting American Manufacturing (CAM) initiative was designed to improve the sourcing capability for Department...addition, CAM was designed to increase the number of US companies bidding on DoD business. The team’s overall approach was based on three major...is to designate a North American Industry Classification System (NAICS) code for each opportunity. Every manufacturing opportunity is posted to

Chemical complexity in the winds of the oxygen-rich supergiant star VY Canis Majoris

NASA Astrophysics Data System (ADS)

Ziurys, L. M.; Milam, S. N.; Apponi, A. J.; Woolf, N. J.

2007-06-01

The interstellar medium is enriched primarily by matter ejected from old, evolved stars. The outflows from these stars create spherical envelopes, which foster gas-phase chemistry. The chemical complexity in circumstellar shells was originally thought to be dominated by the elemental carbon to oxygen ratio. Observations have suggested that envelopes with more carbon than oxygen have a significantly greater abundance of molecules than their oxygen-rich analogues. Here we report observations of molecules in the oxygen-rich shell of the red supergiant star VY Canis Majoris (VY CMa). A variety of unexpected chemical compounds have been identified, including NaCl, PN, HNC and HCO+. From the spectral line profiles, the molecules can be distinguished as arising from three distinct kinematic regions: a spherical outflow, a tightly collimated, blue-shifted expansion, and a directed, red-shifted flow. Certain species (SiO, PN and NaCl) exclusively trace the spherical flow, whereas HNC and sulphur-bearing molecules (amongst others) are selectively created in the two expansions, perhaps arising from shock waves. CO, HCN, CS and HCO+ exist in all three components. Despite the oxygen-rich environment, HCN seems to be as abundant as CO. These results suggest that oxygen-rich shells may be as chemically diverse as their carbon counterparts.

Mapping the Spatial Distribution of Metal-Bearing Oxides in VY Canis Majoris

NASA Astrophysics Data System (ADS)

Burkhardt, Andrew; Booth, S. Tom; Remijan, Anthony; Carroll, Brandon; Ziurys, Lucy M.

2015-06-01

The formation of silicate-based dust grains is not well constrained. Despite this, grain surface chemistry is essential to modern astrochemical formation models. In carbon-poor stellar envelopes, such as the red hypergiant VY Canis Majoris (VY CMa), metal-bearing oxides, the building blocks of silicate grains, dominate the grain formation, and thus are a key location to study dust chemistry. TiO_2, which was only first detected in the radio recently (Kaminski et al., 2013a), has been proposed to be a critical molecule for silicate grain formation, and not oxides containing more abundant metals (eg. Si, Fe, and Mg) (Gail and Sedlmayr, 1998). In addition, other molecules, such as SO_2, have been found to trace shells produced by numerous outflows pushing through the expanding envelope, resulting in a complex velocity structure (Ziurys et al., 2007). With the advanced capabilities of ALMA, it is now possible to individually resolve the velocity structure of each of these outflows and constrain the underlying chemistry in the region. Here, we present high resolution maps of rotational transitions of several metal-bearing oxides in VY CMa from the ALMA Band 7 and Band 9 Science Verification observations. With these maps, the physical parameters of the region and the formation chemistry of metal-bearing oxides will be studied.

Chemical complexity in the winds of the oxygen-rich supergiant star VY Canis Majoris.

PubMed

Ziurys, L M; Milam, S N; Apponi, A J; Woolf, N J

2007-06-28

The interstellar medium is enriched primarily by matter ejected from old, evolved stars. The outflows from these stars create spherical envelopes, which foster gas-phase chemistry. The chemical complexity in circumstellar shells was originally thought to be dominated by the elemental carbon to oxygen ratio. Observations have suggested that envelopes with more carbon than oxygen have a significantly greater abundance of molecules than their oxygen-rich analogues. Here we report observations of molecules in the oxygen-rich shell of the red supergiant star VY Canis Majoris (VY CMa). A variety of unexpected chemical compounds have been identified, including NaCl, PN, HNC and HCO+. From the spectral line profiles, the molecules can be distinguished as arising from three distinct kinematic regions: a spherical outflow, a tightly collimated, blue-shifted expansion, and a directed, red-shifted flow. Certain species (SiO, PN and NaCl) exclusively trace the spherical flow, whereas HNC and sulphur-bearing molecules (amongst others) are selectively created in the two expansions, perhaps arising from shock waves. CO, HCN, CS and HCO+ exist in all three components. Despite the oxygen-rich environment, HCN seems to be as abundant as CO. These results suggest that oxygen-rich shells may be as chemically diverse as their carbon counterparts.

An Interferometric Spectral Line and Imaging Survey of VY Canis Majoris in the 345 GHz Band

NASA Astrophysics Data System (ADS)

Kamiński, T.; Gottlieb, C. A.; Young, K. H.; Menten, K. M.; Patel, N. A.

2013-12-01

A spectral line survey of the oxygen-rich red supergiant VY Canis Majoris was made between 279 and 355 GHz with the Submillimeter Array (SMA). Two hundred twenty-three spectral features from 19 molecules (not counting isotopic species of some of them) were observed, including the rotational spectra of TiO, TiO2, and AlCl for the first time in this source. The parameters and an atlas of all spectral features are presented. Observations of each line with a synthesized beam of ~0.''9, reveal the complex kinematics and morphology of the nebula surrounding VY CMa. Many of the molecules are observed in high-lying rotational levels or in excited vibrational levels. From these, it was established that the main source of the submillimeter-wave continuum (dust) and the high-excitation molecular gas (the star) are separated by about 0.''15. Apparent coincidences between the molecular gas observed with the SMA, and some of the arcs and knots observed at infrared wavelengths and in the optical scattered light by the Hubble Space Telescope are identified. The observations presented here provide important constraints on the molecular chemistry in oxygen-dominated circumstellar environments and a deeper picture of the complex circumstellar environment of VY CMa.

Arcsecond Resolution Mapping of Sulfur Dioxide Emission in the Circumstellar Envelope of VY Canis Majoris

NASA Astrophysics Data System (ADS)

Fu, Roger R.; Moullet, Arielle; Patel, Nimesh A.; Biersteker, John; Derose, Kimberly L.; Young, Kenneth H.

2012-02-01

We report Submillimeter Array observations of SO2 emission in the circumstellar envelope (CSE) of the red supergiant VY Canis Majoris, with an angular resolution of ≈1''. SO2 emission appears in three distinct outflow regions surrounding the central continuum peak emission that is spatially unresolved. No bipolar structure is noted in the sources. A fourth source of SO2 is identified as a spherical wind centered at the systemic velocity. We estimate the SO2 column density and rotational temperature assuming local thermal equilibrium (LTE) as well as perform non-LTE radiative transfer analysis using RADEX. Column densities of SO2 are found to be ~1016 cm-2 in the outflows and in the spherical wind. Comparison with existing maps of the two parent species OH and SO shows the SO2 distribution to be consistent with that of OH. The abundance ratio f_{SO_{2}}/f_{SO} is greater than unity for all radii larger than 3 × 1016 cm. SO2 is distributed in fragmented clumps compared to SO, PN, and SiS molecules. These observations lend support to specific models of circumstellar chemistry that predict f_{SO_{2}}/f_{SO}>1 and may suggest the role of localized effects such as shocks in the production of SO2 in the CSE.

Exotic Metal Molecules in Oxygen-Rich Envelopes: Detection of AlOH (X1Σ^+) in VY Canis Majoris

NASA Astrophysics Data System (ADS)

Tenenbaum, E. D.; Ziurys, L. M.

2010-06-01

A new interstellar molecule, AlOH, has been detected toward the envelope of VY Canis Majoris, an oxygen-rich red supergiant. Three rotational transitions of AlOH were observed using the facilities of the Arizona Radio Observatory (ARO). The J = 9 → 8 and J = 7 → 6 lines at 1 mm were measured with the ARO Submillimeter Telescope (SMT), while the J = 5 → 4 transition at 2 mm was observed with the ARO 12 m antenna on Kitt Peak. The AlOH spectra exhibit quite narrow line widths, indicating that the emission arises from within the dust acceleration zone of the central circumstellar outflow. From a radiative transfer analysis, the abundance of AlOH relative to H_2 was found to be 1x10-7 for a source size of 0.26'' or 22 R_*. AlOH is likely formed just beyond the photosphere via thermodynamic equilibrium chemistry, and then disappears due to dust condensation. The AlOH/AlO abundance ratio found in VY CMa is ˜17. LTE calculations predict the monohydroxides should be the major carriers of Al, Ca, and Mg in O-rich envelopes, as opposed to the oxides or halides.

Experiences in porting NASTRAN (R) to non-traditional platforms

NASA Technical Reports Server (NTRS)

Davis, Gregory L.; Norton, Robert L.

1991-01-01

The 1990 UNIX version of NASTRAN was ported to two new platforms that are not supported by COSMIC: the Sun SPARC workstation and the Apple Macintosh using the A/UX version of UNIX. The experiences of the authers in porting NASTRAN is summarized here. Suggestions for users who might attempt similar ports are given.

Quantized Chiral Magnetic Current from Reconnections of Magnetic Flux

DOE PAGES

Hirono, Yuji; Kharzeev, Dmitri E.; Yin, Yi

2016-10-20

We introduce a new mechanism for the chiral magnetic e ect that does not require an initial chirality imbalance. The chiral magnetic current is generated by reconnections of magnetic ux that change the magnetic helicity of the system. The resulting current is entirely determined by the change of magnetic helicity, and it is quantized.

Laboratory Characterization of Solid Grade SW Brick

DTIC Science & Technology

2007-08-01

Society for Testing and Materials (ASTM) D 2216 (ASTM 2002e). Based on the appropriate values of posttest water content, wet density, and an assumed...strain path (UX/SP) tests. In addition to the mechanical property tests, nondestructive pulse-velocity measurements were performed on each specimen...Figure 3. Spring-arm lateral deformeter mounted on test specimen

Emergent ferromagnetism and T -linear scattering in USb 2 at high pressure

NASA Astrophysics Data System (ADS)

Jeffries, Jason R.; Stillwell, Ryan L.; Weir, Samuel T.; Vohra, Yogesh K.; Butch, Nicholas P.

2016-05-01

The material USb2 is a correlated, moderately heavy-electron compound within the uranium dipnictide (UX2) series. It is antiferromagnetic with a relatively high transition temperature TN=204 K and a large U-U separation. While the uranium atoms in the lighter dipnictides are considered to be localized, those of USb2 exhibit hybridization and itineracy, promoting uncertainty as to the continuity of the magnetic order within the UX2. We have explored the evolution of the magnetic order by employing magnetotransport measurements as a function of pressure and temperature. We find that the TN in USb2 is enhanced, moving towards that of its smaller sibling UAs2. But, long before reaching a TN as high as UAs2, the antiferromagnetism of USb2 is abruptly destroyed in favor of another magnetic ground state. We identify this pressure-induced ground state as being ferromagnetic based on the appearance of a strong anomalous Hall effect in the transverse resistance in magnetic field. With pressure, this emergent ferromagnetic state is suppressed and ultimately destroyed in favor of a non-Fermi-liquid ground state.

Coherent energy scale revealed by ultrafast dynamics of UX3 (X = Al, Sn, Ga) single crystals

NASA Astrophysics Data System (ADS)

Nair, Saritha K.; Zhu, J.-X.; Sarrao, J. L.; Taylor, A. J.; Chia, Elbert E. M.

2012-09-01

The temperature dependence of relaxation dynamics of UX3 (X = Al, Ga, Sn) compounds is studied using the time-resolved pump-probe technique in reflectance geometry. For UGa3, our data are consistent with the formation of a spin density wave gap as evidenced from the quasidivergence of the relaxation time τ near the Néel temperature TN. For UAl3 and USn3, the relaxation dynamics shows a change from single-exponential to two-exponential behavior below a particular temperature, suggestive of coherence formation of the 5f electrons with the conduction band electrons. This particular temperature can be attributed to the spin fluctuation temperature Tsf, a measure of the strength of Kondo coherence. Our Tsf is consistent with other data such as resistivity and susceptibility measurements. The temperature dependence of the relaxation amplitude and time of UAl3 and USn3 were also fitted by the Rothwarf-Taylor model. Our results show that ultrafast optical spectroscopy is sensitive to c-f Kondo hybridization in the f-electron systems.

VizieR Online Data Catalog: Light curves for the eclipsing binary V1094 Tau (Maxted+, 2015)

NASA Astrophysics Data System (ADS)

Maxted, P. F. L.; Hutcheon, R. J.; Torres, G.; Lacy, C. H. S.; Southworth, J.; Smalley, B.; Pavlovski, K.; Marschall, L. A.; Clausen, J. V.

2015-04-01

Photometric light curves of the detached eclipsing binary V1094 Tau in the Stroemgren u-,v-,b- and y-bands, and in the Johnson V-band. The curves in the Stroemgren bands were obtained with the Stroemgren Automatic Telescope (SAT) at ESO, La Silla. The curves in the V-band were obtained with the NFO telescope in New Mexico and with the URSA telescope at the University of Arkansas. (6 data files).

Effect of artificial aging on the bond durability of fissure sealants.

PubMed

Yun, Xiaofei; Li, Wei; Ling, Chen; Fok, Alex

2013-06-01

To evaluate the effect of artificial aging on the bond durability of fissure sealants in vitro. Twenty bovine incisors received 4 different sealant treatments and were divided into four groups: 1. Ultraseal XT plus (UX); 2. Enamel Loc (EL); 3. 35% phosphoric acid plus Enamel Loc (PEL); 4. Adper Prompt L-Pop plus Clinpro (PPC). Beam-shaped specimens were prepared and randomly divided into three subgroups. One subgroup underwent the microtensile bond strength (µTBS) test after 24-h storage in 37°C water. The other two subgroups were also subjected to the microtensile bond strength test after 5000 and 10,000 thermal cycles, respectively. Another twelve intact human third molars were sealed using 1 of 3 methods and were divided into 3 groups of 4 each: 1. Ultraseal XT plus; 2. Adper Prompt L-Pop plus Clinpro; and 3. Enamel Loc. Two specimens from each group were immersed in a 50% silver nitrate solution for 24 h, followed by exposure to fluorescent light for 8 h, before being scanned in a micro-CT (microcomputer tomography) machine. The other two were handled in the same way after undergoing 10,000 thermal cycles. The CT images obtained were evaluated. All samples from the EL group were broken during preparation, so no µTBS results were available. After 5000 thermal cycles, the bond strengths of the three other groups (UX, PEL, PPC) decreased significantly (p < 0.05). Longer thermocycling (10,000 cycles) resulted in more decreases in µTBS for group PEL and PPC, while the strength of the UX group remained relatively unchanged. After thermocycling, considerable silver penetration could be seen at the sealant/enamel interface of the EL group in micro-CT images. The etch-and-rinse procedure for sealant application promotes higher bond strength under artificial aging. Micro-CT, a nondestructive analytical tool, may be used to evaluate the sealant/enamel interface effectively.

User Data Spectrum Theory: Collecting, Interpreting, and Implementing User Data in Organizations

ERIC Educational Resources Information Center

Peer, Andrea Jo

2017-01-01

Organizations interested in increasing their user experience (UX) capacity lack the tools they need to know how to do so. This dissertation addresses this challenge via three major research efforts: 1) the creation of User Data Spectrum theory and a User Data Spectrum survey for helping organizations better invest resources to grow their UX…

77 FR 31871 - Land Acquisitions; Ione Band of Miwok Indians of California

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-30

... THAT CERTAIN BOUNDARY LINE AGREEMENT BY AND BETWEEN NORMAN V. WHEELER, ET UX, AND EVERETT FANCHER, ET... PARTICULARLY DESCRIBED IN PATENT THEREOF FROM THE UNITED STATES OF AMERICA TO JEREMIAH GREEN ET AL, DATED... 3 AND PARCEL 8, AS SHOWN AND DESIGNATED ON PARCEL MAP NO. 2290 FOR NORMAN V. AND BARBARA L. WHEELER...

User Experience in Digital Games: Differences between Laboratory and Home

ERIC Educational Resources Information Center

Takatalo, Jari; Hakkinen, Jukka; Kaistinen, Jyrki; Nyman, Gote

2011-01-01

Playing entertainment computer, video, and portable games, namely, digital games, is receiving more and more attention in academic research. Games are studied in different situations with numerous methods, but little is known about if and how the playing situation affects the user experience (UX) in games. In addition, it is hard to understand and…

The Ages of A-Stars. I. Interferometric Observations and Age Estimates for Stars in the Ursa Major Moving Group

NASA Astrophysics Data System (ADS)

Jones, Jeremy; White, R. J.; Boyajian, T.; Schaefer, G.; Baines, E.; Ireland, M.; Patience, J.; ten Brummelaar, T.; McAlister, H.; Ridgway, S. T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J.

2015-11-01

We have observed and spatially resolved a set of seven A-type stars in the nearby Ursa Major moving group with the Classic, CLIMB, and PAVO beam combiners on the Center for High Angular Resolution Astronomy Array. At least four of these stars have large rotational velocities (v{sin}i ≳ 170 {km} {{{s}}}-1) and are expected to be oblate. These interferometric measurements, the stars’ observed photometric energy distributions, and v{sin}i values are used to computationally construct model oblate stars from which stellar properties (inclination, rotational velocity, and the radius and effective temperature as a function of latitude, etc.) are determined. The results are compared with MESA stellar evolution models to determine masses and ages. The value of this new technique is that it enables the estimation of the fundamental properties of rapidly rotating stars without the need to fully image the star. It can thus be applied to stars with sizes comparable to the interferometric resolution limit as opposed to those that are several times larger than the limit. Under the assumption of coevality, the spread in ages can be used as a test of both the prescription presented here and the MESA evolutionary code for rapidly rotating stars. With our validated technique, we combine these age estimates and determine the age of the moving group to be 414 ± 23 Myr, which is consistent with, but much more precise than previous estimates.

Measurements of anisotropy in the cosmic microwave background radiation at 0.5 deg angular scales near the star gamma ursae minoris

NASA Technical Reports Server (NTRS)

Devlin, M. J.; Clapp, A. C.; Gundersen, J. O.; Hagmann, C. A.; Hristov, V. V.; Lange, A. E.; Lim, M. A.; Lubin, P. M.; Mauskopf, P. D.; Meinhold, P. R.

1994-01-01

We present results from a four-frequency observation of a 6 deg x 0.6 deg strip of the sky centered near the star Gamma Ursae Minoris (GUM) during the fourth flight of the Millimeter-wave Anistropy experiment(MAX). The observation was made with a 1.4 deg peak-to-peak sinusoidal chop in all bands. The FWHM beam sizes were 0.55 deg +/- 0.05 deg at 3.5 per cm and 0.75 deg +/- 0.05 deg at 6, 9, and 14 per cm. During this observation significant correlated structure was observed at 3.5, 6 and 9 per cm with amplitudes similar to those observed in the GUM region during the second and third fligts of MAX. The frequency spectrum is consistent with cosmic microwave background (CMB) and inconsistent with thermal emission from interstellar dust. The extrapolated amplitudes of synchrotron and free-free emission are too small to account for the amplitude of the observed structure, If all of the structure is attributed to CMB anisotropy with a Gaussian autocorrelation function and a coherence angle of 25 min, then the most probable values of delta T/T(sub CMB) in the 3.5, 6 and 9 per cm bads are (4.3 +2.7/-1.6) x 10(exp -5), 2.8 (+4.3/-1/1) x 10(exp -5), and 3.5 (+3.0/-1.6) x 10(exp -5) (95% confidence upper and lower limits), respectively.

Sirius in Ancient Greek and Roman Literature: From the Orphic Argonautics to the Astronomical Tables of Georgios Chrysococca

NASA Astrophysics Data System (ADS)

Theodossiou, Efstratios; Manimanis, Vassilios N.; Dimitrijevi, Milan S.; Mantarakis, Peter Z.

2011-11-01

The brightest star of the night sky, is Sirius, Alpha Canis Majoris (α CMa). Due to its intense brightness, Sirius had one of the dominant positions in ancient mythology, legends and traditions. In this paper the references of the many ancient classical Greek and Roman authors and poets who wrote about Sirius are examined, and the problem of its 'red' color reported in some of these references is discussed.

Infrared Space Observatory Observations of Far-Infrared Rotational Emission Lines of Water Vapor Toward the Supergiant Star VY Canis Majoris

NASA Technical Reports Server (NTRS)

Neufeld, David A.; Feuchtgruber, Helmut; Harwit, Martin; Melnick, Gary J.

1999-01-01

We report the detection of numerous far-infrared emission lines of water vapor toward the supergiant star VY Canis Majoris. A 29.5-45 micron grating scan of VY CMa, obtained using the Short-Wavelength Spectrometer (SWS) of the Infrared Space Observatory at a spectral resolving power lambda/delat.lambda of approximately 2000, reveals at least 41 spectral features due to water vapor that together radiate a total luminosity of approximately 25 solar luminosity . In addition to pure rotational transitions within the ground vibrational state, these features include rotational transitions within the (010) excited vibrational state. The spectrum also shows the (sup 2)product(sub 1/2) (J = 5/2) left arrow (sup 2)product(sub 3/2) (J = 3/2) OH feature near 34.6 micron in absorption. Additional SWS observations of VY CMa were carried out in the instrument's Fabry-Perot mode for three water transitions: the 7(sub 25)-6(sub 16) line at 29.8367 micron, the 4(sub 41)-3(sub 12) line at 31.7721 micron, and the 4(sub 32)-3(sub 03) line at 40.6909 micron. The higher spectral resolving power lambda/delta.lambda of approximately 30,000 thereby obtained permits the line profiles to be resolved spectrally for the first time and reveals the "P Cygni" profiles that are characteristic of emission from an outflowing envelope.

Identification of Phosphorus Monoxide (X2Πr) in VY Canis Majoris: Detection of the First PO Bond in Space

NASA Astrophysics Data System (ADS)

Tenenbaum, E. D.; Woolf, N. J.; Ziurys, L. M.

2007-09-01

A new interstellar molecule, PO (X2Πr), has been detected toward the envelope of the oxygen-rich supergiant star VY Canis Majoris (VY CMa) using the Submillimeter Telescope of the Arizona Radio Observatory. The J=5.5-->4.5 and J=6.5-->5.5 rotational transitions of PO at 240 and 284 GHz were observed, each of which consisted of well-defined lambda-doublets. The line profiles are roughly parabolic in shape, analogous to PN, and suggest that this species arises from the spherical wind in VY CMa, as opposed to the collimated blue- and redshifted outflows. Comparison of line intensities indicates that PO arises from a confined source roughly 1" in extent, with a column density of Ntot ~= 2.8 × 1015 cm-2, which corresponds to a fractional abundance of f~9×10-8, relative to H2. Consequently, PO and PN have similar concentrations in VY CMa, a result not predicted by either LTE or kinetic models of circumstellar chemistry. These phosphorus compounds may arise from shock-induced reactions in this active envelope. Phosphorus monoxide is the first interstellar molecule detected that contains a PO bond, a moiety essential in biochemical compounds. It is also the first new species to be identified in an oxygen-rich, as opposed to a carbon-rich, circumstellar envelope.

The Asymmetric Nebula Surrounding the Extreme Red Supergiant VY Canis Majoris

NASA Astrophysics Data System (ADS)

Smith, Nathan; Humphreys, Roberta M.; Davidson, Kris; Gehrz, Robert D.; Schuster, M. T.; Krautter, Joachim

2001-02-01

We present HST/WFPC2 images plus ground-based infrared images and photometry of the very luminous OH/IR star VY Canis Majoris. Our WFPC2 data show a complex distribution of knots and filamentary arcs in the asymmetric reflection nebula around the obscured central star. The reflection arcs may result from multiple, asymmetric ejection episodes due to localized events on VY CMa's surface. Such events probably involve magnetic fields and convection, by analogy with solar activity. Surface photometry indicates that the star may have experienced enhanced mass loss over the past 1000 yr. We also demonstrate that the apparent asymmetry of the nebula results from a combination of high extinction and backscattering by dust grains. Thermal-infrared images reveal a more symmetric distribution, elongated along a nearly east-west direction. VY CMa probably has a flattened disklike distribution of dust with a northeast-southwest polar axis and may be experiencing activity analogous to solar prominences. The presence of an axis of symmetry raises interesting questions for a star the size of Saturn's orbit. Magnetic fields and surface activity may play an important role in VY CMa's mass-loss history. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

The Three-Dimensional Morphology of VY Canis Majoris. II. Polarimetry and the Line-of-Sight Distribution of the Ejecta

NASA Astrophysics Data System (ADS)

Jones, Terry Jay; Humphreys, Roberta M.; Helton, L. Andrew; Gui, Changfeng; Huang, Xiang

2007-06-01

We use imaging polarimetry taken with the HST Advanced Camera for Surveys High Resolution Camera to explore the three-dimensional structure of the circumstellar dust distribution around the red supergiant VY Canis Majoris. The polarization vectors of the nebulosity surrounding VY CMa show a strong centrosymmetric pattern in all directions except directly east and range from 10% to 80% in fractional polarization. In regions that are optically thin, and therefore likely to have only single scattering, we use the fractional polarization and photometric color to locate the physical position of the dust along the line of sight. Most of the individual arclike features and clumps seen in the intensity image are also features in the fractional polarization map. These features must be distinct geometric objects. If they were just local density enhancements, the fractional polarization would not change so abruptly at the edge of the feature. The location of these features in the ejecta of VY CMa using polarimetry provides a determination of their three-dimensional geometry independent of, but in close agreement with, the results from our study of their kinematics (Paper I). Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

User Experience Design of History Game: An Analysis Review and Evaluation Study for Malaysia Context

ERIC Educational Resources Information Center

Wong, Seng Yue; Ghavifekr, Simin

2018-01-01

User experience (UX) and user interface design of an educational game are important in enhancing and sustaining the utilisation of Game Based Learning (GBL) in learning history. Thus, this article provides a detailed literature review on history learning problems, as well as previous studies on user experience in game design. Future studies on…

Using Vision and Speech Features for Automated Prediction of Performance Metrics in Multimodal Dialogs. Research Report. ETS RR-17-20

ERIC Educational Resources Information Center

Ramanarayanan, Vikram; Lange, Patrick; Evanini, Keelan; Molloy, Hillary; Tsuprun, Eugene; Qian, Yao; Suendermann-Oeft, David

2017-01-01

Predicting and analyzing multimodal dialog user experience (UX) metrics, such as overall call experience, caller engagement, and latency, among other metrics, in an ongoing manner is important for evaluating such systems. We investigate automated prediction of multiple such metrics collected from crowdsourced interactions with an open-source,…

An Empirical Study of User Experience on Touch Mice

ERIC Educational Resources Information Center

Chou, Jyh Rong

2016-01-01

The touch mouse is a new type of computer mouse that provides users with a new way of touch-based environment to interact with computers. For more than a decade, user experience (UX) has grown into a core concept of human-computer interaction (HCI), describing a user's perceptions and responses that result from the use of a product in a particular…

An efficient method for the creation of tunable optical line traps via control of gradient and scattering forces.

PubMed

Tietjen, Gregory T; Kong, Yupeng; Parthasarathy, Raghuveer

2008-07-07

Interparticle interaction energies and other useful physical characteristics can be extracted from the statistical properties of the motion of particles confined by an optical line trap. In practice, however, the potential energy landscape, U(x), imposed by the line provides an extra, and in general unknown, influence on particle dynamics. We describe a new class of line traps in which both the optical gradient and scattering forces acting on a trapped particle are designed to be linear functions of the line coordinate and in which their magnitude can be counterbalanced to yield a flat U(x). These traps are formed using approximate solutions to general relations concerning non-conservative optical forces that have been the subject of recent investigations [Y. Roichman, B. Sun, Y. Roichman, J. Amato-Grill, and D. G. Grier, Phys. Rev. Lett. 100, 013602-4 (2008).]. We implement the lines using holographic optical trapping and measure the forces acting on silica microspheres, demonstrating the tunability of the confining potential energy landscape. Furthermore, we show that our approach efficiently directs available laser power to the trap, in contrast to other methods.

Cloud-based distributed control of unmanned systems

NASA Astrophysics Data System (ADS)

Nguyen, Kim B.; Powell, Darren N.; Yetman, Charles; August, Michael; Alderson, Susan L.; Raney, Christopher J.

2015-05-01

Enabling warfighters to efficiently and safely execute dangerous missions, unmanned systems have been an increasingly valuable component in modern warfare. The evolving use of unmanned systems leads to vast amounts of data collected from sensors placed on the remote vehicles. As a result, many command and control (C2) systems have been developed to provide the necessary tools to perform one of the following functions: controlling the unmanned vehicle or analyzing and processing the sensory data from unmanned vehicles. These C2 systems are often disparate from one another, limiting the ability to optimally distribute data among different users. The Space and Naval Warfare Systems Center Pacific (SSC Pacific) seeks to address this technology gap through the UxV to the Cloud via Widgets project. The overarching intent of this three year effort is to provide three major capabilities: 1) unmanned vehicle control using an open service oriented architecture; 2) data distribution utilizing cloud technologies; 3) a collection of web-based tools enabling analysts to better view and process data. This paper focuses on how the UxV to the Cloud via Widgets system is designed and implemented by leveraging the following technologies: Data Distribution Service (DDS), Accumulo, Hadoop, and Ozone Widget Framework (OWF).

Ergonomic evaluation of ubiquitous computing with monocular head-mounted display

NASA Astrophysics Data System (ADS)

Kawai, Takashi; Häkkinen, Jukka; Yamazoe, Takashi; Saito, Hiroko; Kishi, Shinsuke; Morikawa, Hiroyuki; Mustonen, Terhi; Kaistinen, Jyrki; Nyman, Göte

2010-01-01

In this paper, the authors conducted an experiment to evaluate the UX in an actual outdoor environment, assuming the casual use of monocular HMD to view video content while short walking. In conducting the experiment, eight subjects were asked to view news videos on a monocular HMD while walking through a large shopping mall. Two types of monocular HMDs and a hand-held media player were used, and the psycho-physiological responses of the subjects were measured before, during, and after the experiment. The VSQ, SSQ and NASA-TLX were used to assess the subjective workloads and symptoms. The objective indexes were heart rate and stride and a video recording of the environment in front of the subject's face. The results revealed differences between the two types of monocular HMDs as well as between the monocular HMDs and other conditions. Differences between the types of monocular HMDs may have been due to screen vibration during walking, and it was considered as a major factor in the UX in terms of the workload. Future experiments to be conducted in other locations will have higher cognitive loads in order to study the performance and the situation awareness to actual and media environments.

Emergent ferromagnetism and T -linear scattering in USb 2 at high pressure [Emergent ferromagnetism in USb 2 under pressure

DOE PAGES

Jeffries, Jason R.; Stillwell, Ryan L.; Weir, Samuel T.; ...

2016-05-09

The material USb 2 is a correlated, moderately heavy-electron compound within the uranium dipnictide (UX 2) series. It is antiferromagnetic with a relatively high transition temperature T N = 204K and a large U-U separation. While the uranium atoms in the lighter dipnictides are considered to be localized, those of USb 2 exhibit hybridization and itineracy, promoting uncertainty as to the continuity of the magnetic order within the UX 2. We have explored the evolution of the magnetic order by employing magnetotransport measurements as a function of pressure and temperature. We find that the T N in USb 2 ismore » enhanced, moving towards that of its smaller sibling UAs 2. But, long before reaching a T N as high as UAs 2, the antiferromagnetism of USb 2 is abruptly destroyed in favor of another magnetic ground state. We identify this pressure-induced ground state as being ferromagnetic based on the appearance of a strong anomalous Hall effect in the transverse resistance in magnetic field. At last with pressure, this emergent ferromagnetic state is suppressed and ultimately destroyed in favor of a non-Fermi-liquid ground state.« less

Fast Fuzzy Arithmetic Operations

NASA Technical Reports Server (NTRS)

Hampton, Michael; Kosheleva, Olga

1997-01-01

In engineering applications of fuzzy logic, the main goal is not to simulate the way the experts really think, but to come up with a good engineering solution that would (ideally) be better than the expert's control, In such applications, it makes perfect sense to restrict ourselves to simplified approximate expressions for membership functions. If we need to perform arithmetic operations with the resulting fuzzy numbers, then we can use simple and fast algorithms that are known for operations with simple membership functions. In other applications, especially the ones that are related to humanities, simulating experts is one of the main goals. In such applications, we must use membership functions that capture every nuance of the expert's opinion; these functions are therefore complicated, and fuzzy arithmetic operations with the corresponding fuzzy numbers become a computational problem. In this paper, we design a new algorithm for performing such operations. This algorithm is applicable in the case when negative logarithms - log(u(x)) of membership functions u(x) are convex, and reduces computation time from O(n(exp 2))to O(n log(n)) (where n is the number of points x at which we know the membership functions u(x)).

Cohort: critical science

NASA Astrophysics Data System (ADS)

Digney, Bruce L.

2007-04-01

Unmanned vehicle systems is an attractive technology for the military, but whose promises have remained largely undelivered. There currently exist fielded remote controlled UGVs and high altitude UAV whose benefits are based on standoff in low complexity environments with sufficiently low control reaction time requirements to allow for teleoperation. While effective within there limited operational niche such systems do not meet with the vision of future military UxV scenarios. Such scenarios envision unmanned vehicles operating effectively in complex environments and situations with high levels of independence and effective coordination with other machines and humans pursing high level, changing and sometimes conflicting goals. While these aims are clearly ambitious they do provide necessary targets and inspiration with hopes of fielding near term useful semi-autonomous unmanned systems. Autonomy involves many fields of research including machine vision, artificial intelligence, control theory, machine learning and distributed systems all of which are intertwined and have goals of creating more versatile broadly applicable algorithms. Cohort is a major Applied Research Program (ARP) led by Defence R&D Canada (DRDC) Suffield and its aim is to develop coordinated teams of unmanned vehicles (UxVs) for urban environments. This paper will discuss the critical science being addressed by DRDC developing semi-autonomous systems.

Improving optical performance of GaN nanowires grown by selective area growth homoepitaxy: Influence of substrate and nanowire dimensions

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

Aseev, P., E-mail: pavel.aseev@isom.upm.es, E-mail: gacevic@isom.upm.es; Gačević, Ž., E-mail: pavel.aseev@isom.upm.es, E-mail: gacevic@isom.upm.es; Calleja, E.

2016-06-20

Series of GaN nanowires (NW) with controlled diameters (160–500 nm) and heights (420–1100 nm) were homoepitaxially grown on three different templates: GaN/Si(111), GaN/AlN/Si(111), and GaN/sapphire(0001). Transmission electron microscopy reveals a strong influence of the NW diameter on dislocation filtering effect, whereas photoluminescence measurements further relate this effect to the GaN NWs near-bandgap emission efficiency. Although the templates' quality has some effects on the GaN NWs optical and structural properties, the NW diameter reduction drives the dislocation filtering effect to the point where a poor GaN template quality becomes negligible. Thus, by a proper optimization of the homoepitaxial GaN NWs growth, the propagationmore » of dislocations into the NWs can be greatly prevented, leading to an exceptional crystal quality and a total dominance of the near-bandgap emission over sub-bandgap, defect-related lines, such as basal stacking faults and so called unknown exciton (UX) emission. In addition, a correlation between the presence of polarity inversion domain boundaries and the UX emission lines around 3.45 eV is established.« less

Modeling of transport phenomena in tokamak plasmas with neural networks

DOE PAGES

Meneghini, Orso; Luna, Christopher J.; Smith, Sterling P.; ...

2014-06-23

A new transport model that uses neural networks (NNs) to yield electron and ion heat ux pro les has been developed. Given a set of local dimensionless plasma parameters similar to the ones that the highest delity models use, the NN model is able to efficiently and accurately predict the ion and electron heat transport pro les. As a benchmark, a NN was built, trained, and tested on data from the 2012 and 2013 DIII-D experimental campaigns. It is found that NN can capture the experimental behavior over the majority of the plasma radius and across a broad range ofmore » plasma regimes. Although each radial location is calculated independently from the others, the heat ux pro les are smooth, suggesting that the solution found by the NN is a smooth function of the local input parameters. This result supports the evidence of a well-de ned, non-stochastic relationship between the input parameters and the experimentally measured transport uxes. Finally, the numerical efficiency of this method, requiring only a few CPU-μs per data point, makes it ideal for scenario development simulations and real-time plasma control.« less

Emergent ferromagnetism and T -linear scattering in USb 2 at high pressure [Emergent ferromagnetism in USb 2 under pressure

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

Jeffries, Jason R.; Stillwell, Ryan L.; Weir, Samuel T.

The material USb 2 is a correlated, moderately heavy-electron compound within the uranium dipnictide (UX 2) series. It is antiferromagnetic with a relatively high transition temperature T N = 204K and a large U-U separation. While the uranium atoms in the lighter dipnictides are considered to be localized, those of USb 2 exhibit hybridization and itineracy, promoting uncertainty as to the continuity of the magnetic order within the UX 2. We have explored the evolution of the magnetic order by employing magnetotransport measurements as a function of pressure and temperature. We find that the T N in USb 2 ismore » enhanced, moving towards that of its smaller sibling UAs 2. But, long before reaching a T N as high as UAs 2, the antiferromagnetism of USb 2 is abruptly destroyed in favor of another magnetic ground state. We identify this pressure-induced ground state as being ferromagnetic based on the appearance of a strong anomalous Hall effect in the transverse resistance in magnetic field. At last with pressure, this emergent ferromagnetic state is suppressed and ultimately destroyed in favor of a non-Fermi-liquid ground state.« less

Infrared emission from hydrogenated amorphous carbon and amorphous carbon grains in the interstellar medium

NASA Technical Reports Server (NTRS)

Duley, W. W.; Jones, A. P.; Taylor, S. D.; Williams, D. A.

1993-01-01

The correlations deduced by Boulanger et al. (1990) from IRAS maps of the Chamaeleon, Taurus and Ursa Major molecular cloud complexes are interpreted in terms of the evolutionary hydrogenated amorphous carbon model of interstellar dust. In particular, regions of relatively strong 12-micron emission may be regions where recently accreted carbon is being converted by ambient UV to small PAHs in situ. Regions of weak 12-micron emission are probably quiescent regions where carbon has been annealed to amorphous carbon. Observational consequences of these inferences are briefly described.

http://www.nasa.gov/feature/goddard/2016/hubble-team-breaks-cosmic-distance-record

NASA Image and Video Library

2016-03-03

By pushing NASA’s Hubble Space Telescope to its limits, an international team of astronomers has shattered the cosmic distance record by measuring the farthest galaxy ever seen in the universe. This surprisingly bright infant galaxy, named GN-z11, is seen as it was 13.4 billion years in the past, just 400 million years after the Big Bang. GN-z11 is located in the direction of the constellation of Ursa Major. Read more: go.nasa.gov/1oSqHad

VizieR Online Data Catalog: Spectrum of VY CMa in 220.65-224.25GHz range (Kaminski+, 2013)

NASA Astrophysics Data System (ADS)

Kaminski, T.; Gottlieb, C. A.; Menten, K. M.; Patel, N. A.; Young, K. H.; Brunken, S.; Muller, H. S. P.; McCarthy, M. C.; Winters, J. M.; Decin, L.

2013-02-01

A spectrum of VY Canis Majoris obtained with the Plateau de Bure Interferometer on 22 April and 13 October 2012 in the frequency range 220.65-224.25GHz. The interferometer was used in its D configuration with six antennas and the synthesized beam was 4.9x2.2-arcsec. The spectrum was extracted from the central pixel of the map obtained with the gridding of 0.65-arcsec. (2 data files).

UxV Data to the Cloud via Widgets

DTIC Science & Technology

2013-06-01

data when communications and bandwidth are available. 18th ICCRTS - 051 Introduction “ Information dominance enables end-to-end defense and...C2 capabilities.” Of particular concern is an adversary’s potential for contest our information dominance by “employing the full range of emerging...For Information Dominance . Vice Admiral Michael S. Rogers is the Commander of Fleet Cyber Command/ Commander Tenth Fleet. Together they authored

Inclusive Smartphone Interface Design in Context: Co(Re)designing the PIS.

PubMed

Magee, Paul; Ward, Gillian; Moody, Louise; Roebuck, Annette

2017-01-01

User-context optimises smartphone interface-design. Neglect of user-context during development, delays or prevents marginalised-consumer benefit. Working with People with Learning Disability (PWLD) to develop interfaces refined by communication-need will improve User-Experience (UX). In research, a Participant Information Sheet (PIS) discloses planned study-activity. This paper explains co-creation of a PIS based on communication-need of PWLD.

Different rates of soil drying after rainfall are observed by the SMOS satellite and the South Fork In Situ Soil Moisture Network

USDA-ARS?s Scientific Manuscript database

Soil moisture affects the spatial variation of land–atmosphere interactions through its in'uence on the balance of latent and sensible heat 'ux. Wetter soils are more prone to 'ooding because a smaller fraction of rainfall can in'ltrate into the soil. The Soil Moisture and Oceanic Salinity (SMOS) sa...

Making Scientific Data Usable and Useful

NASA Astrophysics Data System (ADS)

Satwicz, T.; Bharadwaj, A.; Evans, J.; Dirks, J.; Clark Cole, K.

2017-12-01

Transforming geological data into information that has broad scientific and societal impact is a process fraught with barriers. Data sets and tools are often reported to have poor user experiences (UX) that make scientific work more challenging than it needs be. While many other technical fields have benefited from ongoing improvements to the UX of their tools (e.g., healthcare and financial services) scientists are faced with using tools that are labor intensive and not intuitive. Our research team has been involved in a multi-year effort to understand and improve the UX of scientific tools and data sets. We use a User-Centered Design (UCD) process that involves naturalistic behavioral observation and other qualitative research methods adopted from Human-Computer Interaction (HCI) and related fields. Behavioral observation involves having users complete common tasks on data sets, tools, and websites to identify usability issues and understand the severity of the issues. We measure how successfully they complete tasks and diagnosis the cause of any failures. Behavioral observation is paired with in-depth interviews where users describe their process for generating results (from initial inquiry to final results). By asking detailed questions we unpack common patterns and challenges scientists experience while working with data. We've found that tools built using the UCD process can have a large impact on scientist work flows and greatly reduce the time it takes to process data before analysis. It is often challenging to understand the organization and nuances of data across scientific fields. By better understanding how scientists work we can create tools that make routine tasks less-labor intensive, data easier to find, and solve common issues with discovering new data sets and engaging in interdisciplinary research. There is a tremendous opportunity for advancing scientific knowledge and helping the public benefit from that work by creating intuitive, interactive, and powerful tools and resources for generating knowledge. The pathway to achieving that is through building a detailed understanding of users and their needs, then using this knowledge to inform the design of the data products, tools, and services scientists and non-scientists use to do their work.

Catalogue of Main Characteristics of Pulsations of 173 Semi-Regular Stars

NASA Astrophysics Data System (ADS)

Chinarova, L. L.; Andronov, I. L.

2000-12-01

The characteristics of brightness variations of 173 semi-regular stars are tabulated: the moments and brightness of the extrema; the effective periods, amplitudes and significance obtained by using different methods: a) the periodogram analysis (harmonic least squares t) with prewhitening to determine characteristics and significance of waves with 3 periods; b) the wavelet analysis to determine characteristics of statistically significant waves; ) the "running parabola" scalegram analysis to determine the optimal filter half - width for smoothing. The characteristics may be used for more precise classification of semi-regular variables. Characteristics of the 6509 extrema of 147 stars are listed. The electronic version is available via http://ila.webjump.om. The observations for the analysis have been taken from the AFOEV and VSOLJ databases (with a duration up to 94 years) for the stars: AQ, EH, EK, RS, RU, RV, ST, TV, TY, TZ, UX, VX And; GY, PX, S, V, V844 Aql; V, Z Aqr; T Ari; AG, RS, S, UU, Z Aur; RV, RW, RX, RZ, U, V, WY Boo; T Cae; RR, RS, RY, S, ST, U Cam; RT Cap; PZ, SV, UX, V393, V465, WZ Cas; T, Y Cen; AR, RU, RW, RX, SS, TY, W Cep; T Cet; RS, RT, T, X Cnc; RR, RS, TT CrB; V, Y Cvn; AA, AF, AI, AV, AW, BC, RS, RU, RV, RW, RZ, TT, V460, W Cyg; EU, U Del; RS, RY, S, TX, UX, WZ Dra; SY, Z Eri; IS, NQ, RS, SW, TU, TV, Y Gem; DE, MZ, RR, ST, SX, UU, X Her; FF, RT, U, V, W, Y Hya; RS Lac; RY, SX Leo; RX, S Lep; U, W LMi; Y, EG, R, SZ Lyr; RV, SW, X Mon; V759 Oph; BQ, FX, GT, RT, W Ori; AF, AK, SV, TX Peg; AD, BU, DY, FZ, RS, RU, S, SU, SY, T, UZ, W, XX Per; R Pic; RT, RW, Z Psc; BM Sco; S Sct; FG Ser; X Sge; AB, TT, W, Y Tau; W Tri; RX, RY, RZ, ST,SV, V, Y, Z UMa; R, V UMi; RT, SS, SW Vir; RU Vul.

STELLAR ARCHAEOLOGY IN THE GALACTIC HALO WITH THE ULTRA-FAINT DWARFS. VI. URSA MAJOR II

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

Dall'Ora, M.; Ripepi, Vincenzo; Marconi, Marcella

2012-06-10

We present a B, V color-magnitude diagram (CMD) of the Milky Way dwarf satellite Ursa Major II (UMa II), spanning the magnitude range from V {approx} 15 to V {approx} 23.5 mag and extending over an 18 Multiplication-Sign 18 arcmin{sup 2} area centered on the Galaxy. Our photometry goes down to about 2 mag below the Galaxy's main-sequence turnoff that we detected at V {approx} 21.5 mag. We have discovered a bona fide RR Lyrae variable star in UMa II, which we use to estimate a conservative dereddened distance modulus for the galaxy of (m - M){sub 0} = 17.70more » {+-} 0.04 {+-} 0.12 mag, where the first error accounts for the uncertainties of the calibrated photometry, and the second reflects our lack of information on the metallicity of the star. The corresponding distance to UMa II is 34.7{sup +0.6}{sub -0.7}({sup +2.0}{sub -1.9}) kpc. Our photometry shows evidence of a spread in the Galaxy's subgiant branch, compatible with a spread in metal abundance in the range between Z = 0.0001 and Z = 0.001. Based on our estimate of the distance, a comparison of the fiducial lines of the Galactic globular clusters M68 and M5 ([Fe/H] = -2.27 {+-} 0.04 dex and -1.33 {+-} 0.02 dex, respectively), with the position on the CMD of spectroscopically confirmed Galaxy members, may suggest the existence of stellar populations of different metal abundance/age in the central region of UMa II.« less

Application of Rhizon Porewater Samplers to Shipboard Operations, IODP Expedition 308, Northeast Gulf of Mexico

NASA Astrophysics Data System (ADS)

Gilhooly, W. P.; Macko, S. A.; Flemings, P. B.

2005-12-01

Pleistocene and Recent sediments within the Brazos-Trinity and Ursa Basins (northwestern Gulf of Mexico) were largely deposited by turbidity currents and have been deformed by a number of mass transport events. The geochemical composition of interstitial waters was determined in order to assess fluid flow within these sediments. Typical porewater sampling resolution, using advanced piston coring and the traditional Manheim squeezer technique, is approximately one sample every other core (20m) with the highest working resolution at one sample every 1.5m. In this study, Rhizon soil moisture samplers were used to attain high-resolution porewater profiles within sea floor surface sediments and for permeable sediments at depth. The small dimensions (2mm x 30mm) and pore-size (1μm) of the devices enable high-frequency placement within a core, specific targeting of the sequence of interest, and do not require sediment removal from the core, or filtering of extracted porewaters. Initial shipboard analyses derived from sediments at the Ursa Basin (Site 1322) indicate a linear decrease in salinity with depth at U1322 where the overpressure gradient is thought to be greatest. The less saline waters with depth lends evidence for potential mixing between deep-seated fluids and low salinity ones derived from the Blue Unit and seawater. Isotopic composition and concentrations of sulfur species (SO4 and H2S) dissolved in porewaters, as well as, ionic compositions (Cl, Na, K, Ca, Mg) and chemical composition of associated sediments (%C, %N, 13C, and 15N) are compared with chemical results obtained with squeezers.

Evidence for a Sub-Chandrasekhar-mass Type Ia Supernova in the Ursa Minor Dwarf Galaxy

NASA Astrophysics Data System (ADS)

McWilliam, Andrew; Piro, Anthony L.; Badenes, Carles; Bravo, Eduardo

2018-04-01

A long-standing problem is identifying the elusive progenitors of Type Ia supernovae (SNe Ia), which can roughly be split into Chandraksekhar and sub-Chandrasekhar-mass events. An important difference between these two cases is the nucleosynthetic yield, which is altered by the increased neutron excess in Chandrasekhar progenitors due to their pre-explosion simmering and high central density. Based on these arguments, we show that the chemical composition of the most metal-rich star in the Ursa Minor dwarf galaxy, COS 171, is dominated by nucleosynthesis from a low-metallicity, low-mass, sub-Chandrasekhar-mass SN Ia. Key diagnostic abundance ratios include Mn/Fe and Ni/Fe, which could not have been produced by a Chandrasekhar-mass SN Ia. Large deficiencies of Ni/Fe, Cu/Fe and Zn/Fe also suggest the absence of alpha-rich freeze-out nucleosynthesis, favoring low-mass white dwarf progenitors of SNe Ia, near 0.95 M ⊙, from comparisons to numerical detonation models. We also compare Mn/Fe and Ni/Fe ratios to the recent yields predicted by Shen et al., finding consistent results. To explain the [Fe/H] at ‑1.35 dex for COS 171 would require dilution of the SN Ia ejecta with ∼104 M ⊙ of material, which is expected for an SN remnant expanding into a warm interstellar medium with n ∼ 1 cm‑3. In the future, finding more stars with the unique chemical signatures we highlight here will be important for constraining the rate and environments of sub-Chandrasekhar SNe Ia.

Adaptive Optics Imaging of VY Canis Majoris at 2-5 μm with LBT/LMIRCam

NASA Astrophysics Data System (ADS)

Shenoy, Dinesh P.; Jones, Terry J.; Humphreys, Roberta M.; Marengo, Massimo; Leisenring, Jarron M.; Nelson, Matthew J.; Wilson, John C.; Skrutskie, Michael F.; Hinz, Philip M.; Hoffmann, William F.; Bailey, Vanessa; Skemer, Andrew; Rodigas, Timothy; Vaitheeswaran, Vidhya

2013-10-01

We present adaptive optics images of the extreme red supergiant VY Canis Majoris in the Ks , L', and M bands (2.15-4.8 μm) made with LMIRCam on the Large Binocular Telescope. The peculiar "Southwest Clump" previously imaged from 1 to 2.2 μm appears prominently in all three filters. We find its brightness is due almost entirely to scattering, with the contribution of thermal emission limited to at most 25%. We model its brightness as optically thick scattering from silicate dust grains using typical size distributions. We find a lower limit mass for this single feature of 5 × 10-3 M ⊙ to 2.5 × 10-2 M ⊙ depending on the assumed gas-to-dust ratio. The presence of the Clump as a distinct feature with no apparent counterpart on the other side of the star is suggestive of an ejection event from a localized region of the star and is consistent with VY CMa's history of asymmetric high-mass-loss events. The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University; and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.

Infrared Space Observatory Observations of Far-Infrared Rotational Emission Lines of Water Vapor toward the Supergiant Star VY Canis Majoris

NASA Astrophysics Data System (ADS)

Neufeld, David A.; Feuchtgruber, Helmut; Harwit, Martin; Melnick, Gary J.

1999-06-01

We report the detection of numerous far-infrared emission lines of water vapor toward the supergiant star VY Canis Majoris. A 29.5-45 μm grating scan of VY CMa, obtained using the Short-Wavelength Spectrometer (SWS) of the Infrared Space Observatory at a spectral resolving power λ/Δλ of ~2000, reveals at least 41 spectral features due to water vapor that together radiate a total luminosity of ~25 Lsolar. In addition to pure rotational transitions within the ground vibrational state, these features include rotational transitions within the (010) excited vibrational state. The spectrum also shows the 2Π1/2(J=5/2)<--2Π3/2(J=3/2) OH feature near 34.6 μm in absorption. Additional SWS observations of VY CMa were carried out in the instrument's Fabry-Perot mode for three water transitions: the 725-616 line at 29.8367 μm, the 441-312 line at 31.7721 μm, and the 432-303 line at 40.6909 μm. The higher spectral resolving power λ/Δλ of approximately 30,000 thereby obtained permits the line profiles to be resolved spectrally for the first time and reveals the ``P Cygni'' profiles that are characteristic of emission from an outflowing envelope. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands, and the UK) with the participation of ISAS and NASA.

The Arizona Radio Observatory 1 mm Spectral Survey of IRC +10216 and VY Canis Majoris (215-285 GHz)

NASA Astrophysics Data System (ADS)

Tenenbaum, E. D.; Dodd, J. L.; Milam, S. N.; Woolf, N. J.; Ziurys, L. M.

2010-10-01

A low noise (1σ rms ~ 3 mK) 1 mm spectral survey (214.5-285.5 GHz) of the oxygen-rich supergiant VY Canis Majoris and the carbon-rich asymptotic giant branch star IRC +10216 has been conducted using the Arizona Radio Observatory's 10 m Submillimeter Telescope. Here the complete data set is presented. This study, carried out with a new ALMA-type receiver, marks the first continuous band scan of an O-rich circumstellar envelope, and the most sensitive survey to date of IRC +10216. In VY CMa, 130 distinct molecular lines were detected, 14 of which cannot be identified; in IRC +10216, 717 lines were observed, with 126 features remaining unidentified. In the 1 mm bands of VY CMa and IRC +10216, emission is present from 18 and 32 different chemical compounds, respectively, with 10 species common to both sources. Many narrow emission lines were observed in both circumstellar shells, arising from vibrationally excited molecules and from refractory-containing species. Line profiles in VY CMa also exhibit a variety of different shapes, caused by the complex, asymmetric outflow of this object. The survey highlights the fact that C-rich and O-rich circumstellar envelopes are chemically interesting, and both are sources of new interstellar molecules. The high number of unidentified lines and the unreliable rest frequencies for known species such as NaCN indicate the need for additional laboratory spectroscopy studies.

Millimeter Detection of AlO (X^2 Σ ^+): Metal Oxide Chemistry in the Envelope of VY Canis Majoris

NASA Astrophysics Data System (ADS)

Tenenbaum, E. D.; Ziurys, L. M.

2009-06-01

A new circumstellar molecule, the radical AlO (X^2 Σ ^+), has been detected toward the envelope of the oxygen-rich supergiant star VY Canis Majoris (VY CMa) using the Arizona Radio Observatory (ARO). The N = 7 → 6 and 6 → 5 rotational transitions of AlO at 268 and 230 GHz were observed at 1 mm using the ARO Submillimeter Telescope (SMT) and the N = 4 → 3 line was detected at 2 mm using the ARO 12 m. Based on the shape of the line profiles, AlO most likely arises from the dust-forming region in the spherical outflow of VY CMa, as opposed to the blue- or red-shifted winds, with a source size of θ_s ˜ 0.5^''. Given this source size, the column density of AlO was found to be N_{tot} ˜ 2 × 10^{15} cm^{-2} for T_{rot} ˜ 230 K, with a fractional abundance, relative to H_2, of ˜ 10^{-8}. Gas-phase thermodynamic equilibrium chemistry is the likely formation mechanism for AlO in VY CMa, but shocks may disrupt the condensation process into Al_2O_3, allowing AlO to survive to a radius of ˜ 20 R_*. The detection of AlO in VY CMa is additional evidence of an active gas-phase refractory chemistry in oxygen-rich envelopes, and suggests such objects may be fruitful sources for other new oxide identifications.

Millimeter Detection of AlO (X 2Σ+): Metal Oxide Chemistry in the Envelope of VY Canis Majoris

NASA Astrophysics Data System (ADS)

Tenenbaum, E. D.; Ziurys, L. M.

2009-03-01

A new circumstellar molecule, the radical AlO (X 2Σ+), has been detected toward the envelope of the oxygen-rich supergiant star VY Canis Majoris (VY CMa) using the Arizona Radio Observatory (ARO). The N = 7 → 6 and 6 → 5 rotational transitions of AlO at 268 and 230 GHz were observed at 1 mm using the ARO Submillimeter Telescope (SMT) and the N = 4 → 3 line was detected at 2 mm using the ARO 12 m telescope. Based on the shape of the line profiles, AlO most likely arises from the dust-forming region in the spherical outflow of VY CMa, as opposed to the blue or redshifted winds, with a source size of θ s ~ 0farcs5. Given this source size, the column density of AlO was found to be N tot ~ 2 × 1015 cm-2 for T rot ~ 230 K, with a fractional abundance, relative to H2, of ~10-8. Gas-phase thermodynamic equilibrium chemistry is the likely formation mechanism for AlO in VY CMa, but either shocks disrupt the condensation process into Al2O3, or chemical "freezeout" occurs. The species therefore survives further into the circumstellar envelope to a radius of r ~ 20 R *. The detection of AlO in VY CMa is additional evidence of an active gas-phase refractory chemistry in oxygen-rich envelopes, and suggests such objects may be fruitful sources for other new oxide identifications.

Millimeter Detection Of AlO (X2Σ+) In The Oxygen-rich Envelope Of VY Canis Majoris

NASA Astrophysics Data System (ADS)

Tenenbaum, Emily D.; Ziurys, L. M.

2009-05-01

A new circumstellar molecule, the radical AlO (X 2Σ+), has been detected toward the envelope of the oxygen-rich supergiant star VY Canis Majoris (VY CMa) via three rotational emission lines. The N = 7 → 6 and 6 → 5 features of AlO were observed at 1 mm using the Arizona Radio Observatory Submillimeter Telescope (ARO SMT) and the N = 4 → 3 line was detected at 2 mm using the ARO 12 m dish. All lines exhibit noticeable hyperfine broadening due to the I = 5/2 spin of the aluminum nucleus. Based on simulations of the line profiles, AlO most likely arises from the dust-acceleration zone in the spherical outflow of VY CMa, with a source size of θs 0.5''. Given this source size, the column density of AlO was found to be Ntot 2 × 1015 cm-2 for Trot 230 K, with a fractional abundance, relative to H2, of 10-8. Gas-phase thermodynamic equilibrium chemistry is the likely formation mechanism for AlO in VY CMa, but shocks may disrupt the condensation process into Al2O3, allowing AlO to survive 20 stellar radii. The detection of AlO in VY CMa is additional evidence of an active gas-phase refractory chemistry in oxygen-rich envelopes, and suggests such objects may be fruitful sources for other new oxide identifications.

The Arizona Radio Observatory 1 mm Spectral Survey of IRC (plus)10216 and VY Canis Majoris (215-285 GHz)

NASA Technical Reports Server (NTRS)

Tenenbaum, E. D.; Dodd, J. L.; Milam, S. N.; Woolf, N. J.; Ziurys, L. M.

2010-01-01

A low noise (1(sigma) rms approx. 3 mK) 1. nun spectral survey (214.5-285.5 GHz) of the oxygen-rich supergiant VY Canis Majoris and the carbon-rich asymptotic giant branch star IRC +10216 has been conducted using the Arizona Radio Observatory's 10 m Submillimeter Telescope. Here the complete data set is presented. This study, carried out with a new ALMA-type receiver, marks the first continuous band scan of an O-rich circumstellar envelope, and the most sensitive survey to date of IRC +10216. In VY CMa, 130 distinct molecular lines were detected, 14 of which cannot be identified; in IRC +10216, 717 lines were observed, with 126 features remaining unidentified. In the 1 mm bands of VY CMa and IRC +10216, emission is present from 18 and 32 different chemical compounds, respectively, with 10 species common to both sources. Many narrow emission lines were observed in both circumstellar shells, arising from vibrationally excited molecules and from refractory-containing species. Line profiles in VY CMa also exhibit a variety of different shapes, caused by the complex, asymmetric outflow of this object. The survey highlights the fact that C-rich and O-rich circumstellar envelopes are chemically interesting, and both are sources of new interstellar molecules. The high number of unidentified lines and the unreliable, rest frequencies for known species such as NaCN indicate the need for additional laboratory spectroscopy studies.

Adler hantavirus, a new genetic variant of Tula virus identified in Major's pine voles (Microtus majori) sampled in southern European Russia.

PubMed

Tkachenko, Evgeniy A; Witkowski, Peter T; Radosa, Lukas; Dzagurova, Tamara K; Okulova, Nataliya M; Yunicheva, Yulia V; Vasilenko, Ludmila; Morozov, Vyacheslav G; Malkin, Gennadiy A; Krüger, Detlev H; Klempa, Boris

2015-01-01

Although at least 30 novel hantaviruses have been recently discovered in novel hosts such as shrews, moles and even bats, hantaviruses (family Bunyaviridae, genus Hantavirus) are primarily known as rodent-borne human pathogens. Here we report on identification of a novel hantavirus variant associated with a rodent host, Major's pine vole (Microtus majori). Altogether 36 hantavirus PCR-positive Major's pine voles were identified in the Krasnodar region of southern European Russia within the years 2008-2011. Initial partial L-segment sequence analysis revealed novel hantavirus sequences. Moreover, we found a single common vole (Microtusarvalis) infected with Tula virus (TULV). Complete S- and M-segment coding sequences were determined from 11 Major's pine voles originating from 8 trapping sites and subjected to phylogenetic analyses. The data obtained show that Major's pine vole is a newly recognized hantavirus reservoir host. The newfound virus, provisionally called Adler hantavirus (ADLV), is closely related to TULV. Based on amino acid differences to TULV (5.6-8.2% for nucleocapsid protein, 9.4-9.5% for glycoprotein precursor) we propose to consider ADLV as a genotype of TULV. Occurrence of ADLV and TULV in the same region suggests that ADLV is not only a geographical variant of TULV but a host-specific genotype. High intra-cluster nucleotide sequence variability (up to 18%) and geographic clustering indicate long-term presence of the virus in this region. Copyright © 2014. Published by Elsevier B.V.

Development of Prototype Production ESR Facilities

DTIC Science & Technology

1977-07-01

CJISTHIBUTION STATEMENT (ot (he aUxIr&cl entnred in lil^ck 21), If ctlfferert from Wfv.rtj 18. SiJPPi EMENTARV NOTES M9. Kfc y WORDS...Unlike in conventional foundry methods, electroslag castings are made in water-cooled metal molds by remelting of consumable electrodes in... CONSUMABLE ELECTRODE TOP MOLD SLAQ POOL MOLTEN METAL POOL LEVEL DETECTOR MOLTEN METAL POOL ESP INCrOT COPPER LINER mTER JACKET

Distributed Intrusion Detection for Computer Systems Using Communicating Agents

DTIC Science & Technology

2000-01-01

Log for a variety of suspicious events (like repeated failed login attempts), and alerts the IDAgent processes immediately via pipes when it finds...UX, IBM LAN Server, Raptor Eagle Firewalls, ANS Interlock Firewalls, and SunOS BSM. This program appears to be robust across many platforms. EMERALD ...Neumann, 1999] is a system developed by SRI International with research funding from DARPA. The EMERALD project will be the successor to Next

Physics of Cool Stars: Densities, Sizes, and Energetics

NASA Technical Reports Server (NTRS)

Dupree, Andrea K.

2001-01-01

The ORFEUS 1 (Orbiting and Retrievable Far and Extreme Ultraviolet Spectrometer) telescope obtained far ultraviolet spectra (lambda-lambda 912-1218) of luminous cool stars as a part of our observing program. Two classes of objects were measured: luminous single stars beta Dra (HD 159181) and two hybrid stars alpha Aqr (HD 209750) and alpha TrA (HD 150798) and two active binary systems: 44i Boo and UX Ari.

MR 201424 Final Report Addendum

DTIC Science & Technology

2016-09-01

FINAL REPORT ADDENDUM Munitions Classification Library ESTCP Project MR-201424 SEPTEMBER 2016 Mr. Craig Murray Dr. Nagi Khadr Parsons Dr...solver and multi-solver library databases, and only the TEMTADS 2X2 and the MetalMapper advanced TEM systems are supported by UX-Analyze, data on...other steps (section 3.4) before getting into the data collection activities (sections 3.5-3.7). All inversions of library quality data collected over

Remote Excavation of Heavily Contaminated UXO Sites. The Range Master

DTIC Science & Technology

2007-09-05

NUMBER 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 6. AUTHOR(S) 7. PERFORMING ORGANIZATION NAME(S) AND...Master) ESTCP Project UX-200327 ii Final Phase II Report, September 2007 3.5.5 Sampling Plan...Explosive HSP Health and Safety Program HTRW Hazardous, Toxic, and Radioactive Waste HTW Hazardous and Toxic Waste HW Hazardous Waste IAW In

Hand-Held UXO Discriminator

DTIC Science & Technology

2010-04-01

structure design showed that we could achieve both of these goals with a 14-in (0.35 m) sensor cube. To avoid the reliance on accurate multiple...differenced pair receiver. 4. Conclusions We have designed and built a sensor package of a 14-in (0.35 m) cube based on the...funding (UX-1225, MM-0437, and MM-0838), we have successfully designed and built a cart-mounted Berkeley UXO Discriminator (BUD) and demonstrated its

Pulsatile Flow and Transport of Blood past a Cylinder: Basic Transport for an Artificial Lung.

NASA Astrophysics Data System (ADS)

Zierenberg, Jennifer R.

2005-11-01

The fluid mechanics and transport for flow of blood past a single cylinder is investigated using CFD. This work refers to an artificial lung in which oxygen travels through fibers oriented perpendicularly to the incoming blood flow. A pulsatile blood flow was considered: Ux=U0[ 1+A( φt ) ], where Ux is the velocity far from the cylinder. The Casson equation was used to describe the shear thinning and yield stress properties of blood. The presence of hemoglobin (i.e. facilitated diffusion) was considered. We examined the effect of A, U0 and φ on the flow and transport by varying the dimensionless parameters: A; Reynolds number, Re; and Womersley parameter, α. Two different feed gases were considered: pure O2 and air. The flow and concentration fields were computed for Re = 5, 10, and 40, 0 <=A<= 0.75, α = 0.25, 0.4, and Schmidt number, Sc = 1000. Vortices attached downstream of the cylinder are found to oscillate in size and strength as α and A are varied. Mass transport is found to primarily depend on Re and to increase with increasing Re, α and decreasing A. The presence of hemoglobin increases mass transport. Supported by NIH HL69420, NSF Fellowship

Measurement and Analysis of Failures in Computer Systems

NASA Technical Reports Server (NTRS)

Thakur, Anshuman

1997-01-01

This thesis presents a study of software failures spanning several different releases of Tandem's NonStop-UX operating system running on Tandem Integrity S2(TMR) systems. NonStop-UX is based on UNIX System V and is fully compliant with industry standards, such as the X/Open Portability Guide, the IEEE POSIX standards, and the System V Interface Definition (SVID) extensions. In addition to providing a general UNIX interface to the hardware, the operating system has built-in recovery mechanisms and audit routines that check the consistency of the kernel data structures. The analysis is based on data on software failures and repairs collected from Tandem's product report (TPR) logs for a period exceeding three years. A TPR log is created when a customer or an internal developer observes a failure in a Tandem Integrity system. This study concentrates primarily on those TPRs that report a UNIX panic that subsequently crashes the system. Approximately 200 of the TPRs fall into this category. Approximately 50% of the failures reported are from field systems, and the rest are from the testing and development sites. It has been observed by Tandem developers that fewer cases are encountered from the field than from the test centers. Thus, the data selection mechanism has introduced a slight skew.

Coherence of simulated atmospheric boundary-layer turbulence

NASA Astrophysics Data System (ADS)

Jiadong, Zeng; Zhiguo, Li; Mingshui, Li

2017-12-01

The coherences in a plane perpendicular to incoming flow are measured in wind tunnel simulations of atmospheric turbulent flow. The measured coherences are compared with analytical expressions tailored to field measurements and with theoretical coherence models which assume homogeneous turbulence and the von Kármán’s spectrum. The comparison indicates that the simulated atmospheric boundary layer flow is approximately horizontally homogeneous turbulence. Based on the above assumption and the systematic analysis of lateral coherence, it can be concluded that the lateral coherences of simulated atmospheric boundary turbulence can be determined accurately using the von Kármán spectrum and the turbulence parameters measured by a few measurement points. The measured results also show that the spatial characteristics of vertical coherences are closely related to the dimensionless parameter {{Δ }}z/({\\bar{z}}0.3{L}ux 0.7). The vertical coherence at two heights can be roughly estimated by the ratio to {{Δ }}z/({\\bar{z}}0.3{L}ux 0.7). The relationship between the phase angles of u-, v- and w-components and the vertical separation distance and the height from the ground is further analyzed. Finally, the roles of the type of land surface roughness, the height from the ground, the turbulence intensity and the integral length scale in lateral and vertical coherences are also discussed in this study.

ASSIGNMENT OF 5069 A DIFFUSE INTERSTELLAR BAND TO HC{sub 4}H{sup +}: DISAGREEMENT WITH LABORATORY ABSORPTION BAND

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

Maier, J. P.; Chakrabarty, S.; Mazzotti, F. J.

2011-03-10

Krelowski et al. have reported a weak, diffuse interstellar band (DIB) at 5069 A which appears to match in both mid-wavelength and width the A {sup 2}{Pi}{sub u}-X {sup 2}{Pi}{sub g} gas-phase origin absorption band of HC{sub 4}H{sup +}. Here, we present laboratory rotational profiles at low temperatures which are then compared with the 5069 A DIB using {approx}0.1 and 0.3 A line widths based on a realistic line-of-sight interstellar velocity dispersion. Neither the band shape nor the wavelength of the maximum absorption match, which makes the association of the 5069 A DIB with HC{sub 4}H{sup +} unlikely. The magneticmore » dipole transition X {sup 2}{Pi}{sub g} {Omega} = 1/2{yields}X {sup 2}{Pi}{sub g} {Omega} = 3/2 within the ground electronic state which competes with collisional excitation is also considered. In addition, we present the laboratory gas-phase spectrum of the A {sup 2}{Pi}{sub u}-X {sup 2}{Pi}{sub g} transition of HC{sub 4}H{sup +} measured at 25 K in an ion trap and identify further absorption bands at shorter wavelengths for comparison with future DIB data.« less

My Summer Internship at Kennedy Space Center

NASA Technical Reports Server (NTRS)

Philpott, Hobert Leon

2011-01-01

During my summer internship at Kennedy Space Center, I worked on several projects with my mentor Grace Johnson in the Education Programs Office. My primary project was the CubeSat project in which my job was to help mentor Merritt Island High School students in the building of a CubeSat. CubeSats are picosatellites that are used to carry out auxiliary missions; they "piggy back" into orbit on launch vehicles launching primary missions. CubeSats come in the sizes of 1U (10 by 10 by 10 cm) 2U (1Ux2) and 3U (1Ux3). The Cube Sats are housed in a protective deploying device called a Poly Picosatellite Orbital Deplored (P-POD). I also participated in a Balloon Workshop with the MIHS students. This was an intense 4-day project in which we constructed a balloon satellite equipped with a camera whose main goal was to obtain video images of the curvature of the earth at high altitudes and relay it back down to our ground station. I also began developing my own science research program for minority serving institutions to be implemented when funding becomes available. In addition to the projects that I completed during my internship, I got the opportunity to go on various tours of the technological facilities here at Kennedy Space Center.

Obstructions to Existence in Fast-Diffusion Equations

NASA Astrophysics Data System (ADS)

Rodriguez, Ana; Vazquez, Juan L.

The study of nonlinear diffusion equations produces a number of peculiar phenomena not present in the standard linear theory. Thus, in the sub-field of very fast diffusion it is known that the Cauchy problem can be ill-posed, either because of non-uniqueness, or because of non-existence of solutions with small data. The equations we consider take the general form ut=( D( u, ux) ux) x or its several-dimension analogue. Fast diffusion means that D→∞ at some values of the arguments, typically as u→0 or ux→0. Here, we describe two different types of non-existence phenomena. Some fast-diffusion equations with very singular D do not allow for solutions with sign changes, while other equations admit only monotone solutions, no oscillations being allowed. The examples we give for both types of anomaly are closely related. The most typical examples are vt=( vx/∣ v∣) x and ut= uxx/∣ ux∣. For these equations, we investigate what happens to the Cauchy problem when we take incompatible initial data and perform a standard regularization. It is shown that the limit gives rise to an initial layer where the data become admissible (positive or monotone, respectively), followed by a standard evolution for all t>0, once the obstruction has been removed.

Young Stellar Variability of GM Cephei by Circumstellar Dust Clumps

NASA Astrophysics Data System (ADS)

Huang, Po-Chieh; Chen, Wen-Ping; Hu, Chia-Ling; Burkhonov, Otabek; Ehgamberdiev, Shuhrat; Liu, Jinzhong; Naito, Hiroyuki; Pakstiene, Erika; Qvam, Jan Kare Trandem; Rätz, Stefanie; Semkov, Evgeni

2018-04-01

UX Orionis stars are a sub-type of Herbig Ae/be or T Tauri stars exhibiting sporadic extinction of stellar light due to circumstellar dust obscuration. GM Cep is such an UX Orionis star in the young (∼ 4 Myr) open cluster Trumpler 37 at ∼ 900 pc, showing a prominent infrared access, H-alpha emission, and flare activity. Our multi-color photometric monitoring from 2009 to 2016 showed (i) sporadic brightening on a time scale of days due to young stellar accretion, (ii) cyclic, but not strictly periodical, occultation events, each lasting for a couple months, with a probable recurrence time of about two years, (iii) normal dust reddening as the star became redder when dimmer, (iv) the unusual "blueing" phenomena near the brightness minima, during which the star appeared bluer when dimmer, and (v) a noticeable polarization, from 3 to 9 percent in g', r', and i' -bands. The occultation events may be caused by dust clumps, signifying the density inhomogeneity in a young stellar disk from grain coagulation to planetesimal formation. The level of polarization was anti-correlated with the brightness in the bright state, when the dust clump backscattered stellar light. We discussed two potential hypotheses: orbiting dust clumps versus dust clumps along a spiral arm structure.

Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging: III. Measurement for URSA Minor

DTIC Science & Technology

2005-07-01

velocity of 249:2 1:5 km s1 from the radial velocities of 35 giants. Armandroff et al. (1995) combined the data from Hargreaves Fig. 1.—Left: Image...dispersion; Hargreaves et al. (1994) find 7:5þ1:00:9 km s 1 from a sample of 35 giants, and Armandroff et al. (1995) find 8:8 0:8 km s1 from a sample of...beyond this radius, the ve- locity dispersion drops sharply to about 2 km s1. Hargreaves et al. (1994) and Armandroff et al. (1995) assume virial

A Keck/DEIMOS spectroscopic survey of faint Galactic satellites: searching for the least massive dwarf galaxies

NASA Astrophysics Data System (ADS)

Martin, N. F.; Ibata, R. A.; Chapman, S. C.; Irwin, M.; Lewis, G. F.

2007-09-01

We present the results of a spectroscopic survey of the recently discovered faint Milky Way satellites Boötes, Ursa Major I, Ursa Major II and Willman 1 (Wil1). Using the DEep Imaging Multi-Object Spectrograph mounted on the Keck II telescope, we have obtained samples that contain from ~15 to ~85 probable members of these satellites for which we derive radial velocities precise to a few kms-1 down to i ~ 21-22. About half of these stars are observed with a high enough signal-to-noise ratio to estimate their metallicity to within +/-0.2 dex. The characteristics of all the observed stars are made available, along with those of the Canes Venatici I dwarf galaxy that have been analysed in a companion paper. From this data set, we show that Ursa Major II is the only object that does not show a clear radial velocity peak. However, the measured systemic radial velocity (vr = 115 +/- 5kms-1) is in good agreement with simulations in which this object is the progenitor of the recently discovered Orphan Stream. The three other satellites show velocity dispersions that make them highly dark matter dominated systems (under the usual assumptions of symmetry and virial equilibrium). In particular, we show that despite its small size and faintness, the Wil1 object is not a globular cluster given its metallicity scatter over -2.0 <~ [Fe/H] <~ -1.0 and is therefore almost certainly a dwarf galaxy or dwarf galaxy remnant. We measure a radial velocity dispersion of only 4.3+2.3-1.3kms-1 around a systemic velocity of -12.3 +/- 2.3kms-1 which implies a mass-to-light ratio of ~700 and a total mass of ~5 × 105Msolar for this satellite, making it the least massive satellite galaxy known to date. Such a low mass could mean that the 107Msolar limit that had until now never been crossed for Milky Way and Andromeda satellite galaxies may only be an observational limit and that fainter, less massive systems exist within the Local Group. However, more modelling and an extended search for potential extratidal stars are required to rule out the possibility that these systems have not been significantly heated by tidal interaction. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The observatory was made possible by the generous financial support of the W. M. Keck Foundation. E-mail: martin@mpia-hd.mpg.de ‡ Canadian Space Agency Fellow.

The eight micron band of silicon monoxide in the expanding cloud around VY Canis Majoris

NASA Technical Reports Server (NTRS)

Geballe, T. R.; Lacy, J. H.; Beck, S. C.

1978-01-01

Observations of vibration-rotation transitions of silicon monoxide in VY CMa show that the lines originate in accelerating, expanding, and cool (600 K) layers of a circumstellar cloud at a distance of roughly 0.15 minutes from the central star. The central stellar velocity, as estimated from observed SiO P Cygni line profiles, is somewhat redshifted from the midpoint of the maser emission features. Most of the silicon is probably in the form of dust grains. The isotopic ratios of silicon are nearly terrestrial.

Rapid Fluctuations of Water Maser Emission in VY Canis Majoris

NASA Astrophysics Data System (ADS)

Zheng, Xing Wu; Scalise, Eugenio, Jr.; Han, Fu

1998-11-01

We report the observational results of short timescale monitoring of the 22 GHz water maser emission in VY CMa. A quasi-sinusoidal fluctuation has been detected with the relative flux intensity change of 20%-25% and a period of 10.3 day for two dominant features. This detected variability appears to be superimposed on the normal maser lines. We cannot easily explain the rapid fluctuation with the variation of the radiative input or the strong interstellar scintillation along the line of sight. The variation may be caused by the periodic shock.

The 8 micron band of silicon monoxide in the expanding cloud around VY Canis Majoris

NASA Technical Reports Server (NTRS)

Geballe, T. R.; Lacy, J. H.; Beck, S. C.

1979-01-01

Observations of vibration-rotation transitions of silicon monoxide in VY CMa show that the lines originate in accelerating, expanding, and cool (about 600 K) layers of a circumstellar cloud at a distance of approximately 0.15 arcsec from the central star. The central stellar velocity, as estimated from observed SiO P Cygni line profiles, is somewhat redshifted from the midpoint of the maser emission features. Most of the silicon is probably in the form of dust grains. The isotopic ratios of silicon are nearly terrestrial.

SDP_mharwit_1: Demonstration of HIFI Linear Polarization Analysis of Spectral Features

NASA Astrophysics Data System (ADS)

Harwit, M.

2010-03-01

We propose to observe the polarization of the 621 GHz water vapor maser in VY Canis Majoris to demonstrate the capability of HIFI to make polarization observations of Far-Infrared/Submillimeter spectral lines. The proposed Demonstration Phase would: - Show that HIFI is capable of interesting linear polarization measurements of spectral lines; - Test out the highest spectral resolving power to sort out closely spaced Doppler components; - Determine whether the relative intensities predicted by Neufeld and Melnick are correct; - Record the degree and direction of linear polarization for the closely-Doppler shifted peaks.

The Circumstellar Environment of VY CMa

NASA Astrophysics Data System (ADS)

Smith, N.; Humphreys, R. M.; Krautter, J.; Gehrz, R. D.; Davidson, K.; Jones, T. J.; Hubrig, S.

1999-05-01

VY Canis Majoris is one of the most luminous known M supergiants. It is near the upper liminosity limit for cool stars on the HR Diagram. The optical star is partially obscured by its own circumstellar material. We present preliminary results of recent HST/WFPC2 optical imaging, and ground-based near-IR and mid-IR imaging of VY CMa and its circumstellar environment. We compare these results with previously obtained images of the related, but more evolved object IRC+10420 and discuss implications for their possible evolutionary and mass loss histories.

Addressing Earth Science Data Access Challenges through User Experience Research

NASA Astrophysics Data System (ADS)

Hemmings, S. N.; Banks, B.; Kendall, J.; Lee, C. M.; Irwin, D.; Toll, D. L.; Searby, N. D.

2013-12-01

The NASA Capacity Building Program (Earth Science Division, Applied Sciences Program) works to enhance end-user capabilities to employ Earth observation and Earth science (EO/ES) data in decision-making. Open data access and user-tailored data delivery strategies are critical elements towards this end. User Experience (UX) and User Interface (UI) research methods can offer important contributions towards addressing data access challenges, particularly at the interface of science application/product development and product transition to end-users. This presentation focuses on developing nation contexts and describes methods, results, and lessons learned from two recent UX/UI efforts conducted in collaboration with NASA: the SERVIRglobal.net redesign project and the U.S. Water Partnership (USWP) Portal development effort. SERVIR, a collaborative venture among NASA, USAID, and global partners, seeks to improve environmental management and climate change response by helping governments and other stakeholders integrate EO and geospatial technologies into decision-making. The USWP, a collaboration among U.S. public and private sectors, harnesses U.S.-based resources and expertise to address water challenges in developing nations. SERVIR's study, conducted from 2010-2012, assessed and tested user needs, preferences, and online experiences to generate a more user-friendly online data portal at SERVIRglobal.net. The portal provides a central access interface to data and products from SERVIR's network of hubs in East Africa, the Hindu Kush Himalayas, and Mesoamerica. The second study, conducted by the USWP Secretariat and funded by the U.S. Department of State, seeks to match U.S.-based water information resources with developing nation stakeholder needs. The USWP study utilizes a multi-pronged approach to identify key design requirements and to understand the existing water data portal landscape. Adopting UX methods allows data distributors to design customized UIs that help users find, interpret, and obtain appropriate content quickly. The data access challenge for both SERVIR and USWP consisted of organizing a wide range of content for their respective user bases, which are diverse, international, and in some cases loosely characterized. The UX/UI design approach generated profiles of prototypical users and corresponding task flows and organizational schemes for their preferred types of content. Wireframe acceptance testing by SERVIR helped elicit and optimize how users interact with the information online. These approaches produced customized UIs and knowledge management strategies to address the data access challenges faced by each user type. Both studies revealed critical considerations for user experiences in developing nations (e.g., low-bandwidth internet connections, rolling power outages at data storage or network centers). For SERVIR, these findings influenced not only the portal infrastructure; they also informed the transition of the platform to a Cloud-based model, as well as the development of custom data delivery tools such as SMS and other mobile solutions. While SERVIR's data access solutions are customized for the network's community of users, they are also standardized and interoperable according to GEO and ISO standards, providing a model for other initiatives such as the ongoing USWP Portal development effort.

THE LEECH EXOPLANET IMAGING SURVEY: ORBIT AND COMPONENT MASSES OF THE INTERMEDIATE-AGE, LATE-TYPE BINARY NO UMa

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

Schlieder, Joshua E.; Skemer, Andrew J.; Hinz, Philip

2016-02-10

We present high-resolution Large Binocular Telescope LBTI/LMIRcam images of the spectroscopic and astrometric binary NO UMa obtained as part of the LBT Interferometer Exozodi Exoplanet Common Hunt exoplanet imaging survey. Our H-, K{sub s}-, and L′-band observations resolve the system at angular separations <0.″09. The components exhibit significant orbital motion over a span of ∼7 months. We combine our imaging data with archival images, published speckle interferometry measurements, and existing spectroscopic velocity data to solve the full orbital solution and estimate component masses. The masses of the K2.0 ± 0.5 primary and K6.5 ± 0.5 secondary are 0.83 ± 0.02 M{sub ⊙} and 0.64 ± 0.02 M{sub ⊙},more » respectively. We also derive a system distance of d = 25.87 ± 0.02 pc and revise the Galactic kinematics of NO UMa. Our revised Galactic kinematics confirm NO UMa as a nuclear member of the ∼500 Myr old Ursa Major moving group, and it is thus a mass and age benchmark. We compare the masses of the NO UMa binary components to those predicted by five sets of stellar evolution models at the age of the Ursa Major group. We find excellent agreement between our measured masses and model predictions with little systematic scatter between the models. NO UMa joins the short list of nearby, bright, late-type binaries having known ages and fully characterized orbits.« less

Turbine Engine Flowpath Averaging Techniques

DTIC Science & Technology

1980-10-01

u~%x AEDC- TMR- 8 I-G 1 • R. P TURBINE ENGINE FLOWPATH AVERAGING TECHNIQUES T. W. Skiles ARO, Inc. October 1980 Final Report for Period...COVERED 00-01-1980 to 00-10-1980 4. TITLE AND SUBTITLE Turbine Engine Flowpath Averaging Techniques 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...property for gas turbine engines were investigated. The investigation consisted of a literature review and review of turbine engine current flowpath

Crystal Growth and Characterization of THO2 and UxTh1-xO2

DTIC Science & Technology

2013-03-01

bulk actinide crystals would open up new possibilities for the detection of weapons of mass destruction, the study of the effect of aging on...way of growing bulk actinide materials of optical quality. These refractory oxide single crystals offer potential applications in thorium nuclear...fuel technology, wide-band-gap uranium-based direct-conversion solid state neutron detectors, and understanding how actinide fuels age with time. ThO2

An algorithm for the Baker-Campbell-Hausdorff formula

NASA Astrophysics Data System (ADS)

Matone, Marco

2015-05-01

A simple algorithm, which exploits the associativity of the BCH formula, and that can be generalized by iteration, extends the remarkable simplification of the BakerCampbell-Hausdorff (BCH) formula, recently derived by Van-Brunt and Visser. We show that if [ X, Y] = uX + vY + cI, [ Y, Z] = wY + zZ + dI, and, consistently with the Jacobi identity, [ X, Z] = mX + nY + pZ + eI, then

Initial Evaluation of the Intelligent Multi-UxV Planner with Adaptive Collaborative/Control Technologies (IMPACT)

DTIC Science & Technology

2017-02-17

Psychology. Brooke, J. (1996). SUS: a ‘quick and dirty ’ usability scale. In P. Jordan, B. Thomas, I. McClelland, & B. Weerdmeester (Eds.), Usability...level modeling, International Journal of Human Computer Studies, Vol. 45(3). Menzies, T. (1996b). On the Practicality of Abductive Validation, ECAI...1). Shima, T., & Rasmussen, S. (2009). UAV Cooperative Decision and Control: Challenges and Practical Approaches, SIAM Publications, ISBN

Material Response Characterization

DTIC Science & Technology

1977-08-01

models fit to vertical UX and TX data and a mean stress tension cutoff criterion. Because tests on the Kayenta sands one materials had revealed a definite...parameters. 9 This data characterizing the anisotropic response of the upper 30 feet of Kayenta material should not just be filed away; it should be used...9. Johnson, J. N., et al, "Anisotropic Mechanical Properties of Kayenta Sandstone (MIXED COMPANY Site) for Ground Motion Calculations," Terra Tek TR

Millimeter wave studies of circumstellar chemistry

NASA Astrophysics Data System (ADS)

Tenenbaum, Emily Dale

2010-06-01

Millimeter wave studies of molecules in circumstellar envelopes and a planetary nebula have been conducted. Using the Submillimeter Telescope (SMT) of the Arizona Radio Observatory (ARO) on Mt. Graham, a comparative spectral survey from 215-285 GHz was carried out of the carbon-rich asymptotic giant branch star IRC +10216 and the oxygen-rich supergiant VY Canis Majoris. A total of 858 emission lines were observed in both objects, arising from 40 different molecules. In VY Canis Majoris, AlO, AlOH, and PO were detected for the first time in interstellar space. In IRC +10216, PH3 was detected for the first time beyond the solar system, and C3O, and CH2NH were found for the first time in a circumstellar envelope. Additionally, in the evolved planetary nebula, the Helix, H2CO, C2H, and cyclic-C3H2 were observed using the SMT and the Kitt Peak 12 m telescopes. The presence of these three molecules in the Helix suggests that relatively complex chemistry occurs in planetary nebulae, despite the harsh ultraviolet field. Overall, the research on molecules in circumstellar and planetary nebulae furthers our understanding of the nature of the material that is fed back into the interstellar medium from evolved stars. Besides telescope work, laboratory research was also conducted -- the rotational spectrum of ZnCl was measured and its bond length and rotational constants were determined. Lastly, in partial fulfillment of a graduate certificate in entrepreneurial chemistry, the commercial applications of terahertz spectroscopy were explored through literature research.

United States Air Force High School Apprenticeship Program. 1990 Program Management Report. Volume 1

DTIC Science & Technology

1991-04-18

12.59498 50 0750 B AURIGA COLURE 2.1 88.96491 44.94464 51 3765 A ANDROMEDA SIRRAH*** 2.1 1.44934 28.81448 52 0878 C VELA 2.2 136.53879 - 43.22989 53...251.73003 - 14.2043273 4471 B ANDROMEDA MIRACH 2.4 16.73107 .j.3560474 5093 A PHOENIX ----- 2.4 5.95429 - 42,5773775 7876 B URSA MAJOR MERAK 2.4...158 0734 N ANDROMEDA 3.1 340.16360 29.95928 159 9696 C SAGITTARIUS 3.1 270.64865 - 30.42661 160 4538 Z CENTAURUS 3.1 208.10213 - 47.04302 161 3629 W

Interpretation of 2-probe turbulence measurements in an axisymmetric contraction

NASA Technical Reports Server (NTRS)

Marion-Moulin, C.; Tan-Atichat, J.; Nagib, H. M.

1983-01-01

Simultaneous measurements of the streamwise and radial velocity components at two points, one on and one off the centerline with variable radial separation, were digitally recorded and processed at several stations along a four to one contraction with controlled upstream turbulence conditions. Various statistical quantities are presented including spectra and coherence functions. The integral L sub ux, L sub um, L sub vx, L sub vm were also estimated and their variation along the contraction is examined.

OSSE Observations of Active Galaxies and Quasars

DTIC Science & Technology

1993-01-01

exception of Centaurus A and NGC 4151, there is little evidence of signi cant ux variability in the OSSE data sets for most of the Seyfert galaxies observed... Centaurus A. The other Seyfert 1 galaxies that have been detected generally show weak emission at hard x-ray energies, except for NGC 4151, which has a...detections will be given elsewhere as the nal analysis is completed for each object. Variability has been detected in three objects: Centaurus A

Validation Summary Report: Verdix Corporation, VADSself HP 9000 Series 700 VAda-110-7575, Version 6.2, HP 9000/720 Under HP/UX 8.0.7 (Host & Target), 930226W1.11311

DTIC Science & Technology

1993-02-26

2-89) Prescribed by ANSI Sid 239-128 AVF Control Number: AVF-VSR-561-0293 Date VSR Completed: 15 February 1993 93-01-25- VRX Ada COMPILER VALIDATION...Agreement Number: 93-01-2S- VRX See section 3.1 for any additional information about the testing environment. As a result of this validation effort

User-Centred Design Using Gamestorming.

PubMed

Currie, Leanne

2016-01-01

User-centered design (UX) is becoming a standard in software engineering and has tremendous potential in healthcare. The purpose of this tutorial will be to demonstrate and provide participants with practice in user-centred design methods that involve 'Gamestorming', a form of brainstorming where 'the rules of life are temporarily suspended'. Participants will learn and apply gamestorming methods including persona development via empathy mapping and methods to translate artefacts derived from participatory design sessions into functional and design requirements.

Assessing the Impact of Low Workload in Supervisory Control of Networked Unmanned Vehicles

DTIC Science & Technology

2010-06-01

influence is expected to contain men and women between the ages of 18 and 50 with an interest in using computers. You should read the information below...controlling land, air, and sea vehicles of all different types from the same supervisory control interface. As human supervisory control of UxVs...expressions indicated when boredom was occurring. Video coding shows that humans deal with boredom in different ways. Some individuals are more

Smart Collection and Storage Method for Network Traffic Data

DTIC Science & Technology

2014-09-01

to the root of an incident or under- stand what goes on in a network may mean looking at data from weeks, months, or even years ago, as has been the...KB 1.01% 69.42 TB 694.20 TB 6,941.99 TB SuSE 6.3 .pcap 51,706 KB 1.01% 104.03 TB 1,040.27 TB 10,402.68 TB HP-UX nettl .trc0 53,391 KB 1.04% 451.13

Third All-Union Symposium on Wave Diffraction.

DTIC Science & Technology

1982-08-02

the Half - Plane of Waves, Formed on the Surface of Liquid and on the Interface in the Laminar Liquid by the Periodically Functioning Source, by...majority of the cases is of basic practical interest. For this way of integration it is displaced into lower half - plane Im xɘ and are computed deductions...and f(x) exponentially decrease, then u(x, p) is continued as meromorphic function for the variable/alternating p into half - plane Re p>-b,

Enhancing Therapeutic Cellular Prostate Cancer Vaccines

DTIC Science & Technology

2013-06-01

associated antigens Present ation Time: Tuesday, Apr 09, 2013, ! 00 PM - 5 00 PM Loc ation : Poster Board Number Author Block: Ab stract...an m.unber of m:utrophils cow11ed in leo 40Ux fidds ± SEM. The tota l tissue area across which cells were counted was quantified and determined’ to...2005), EtTccls of "Y~t.:mlo anll loc -.u CXC chemokine administration on the ethanol-indtrced suppre;;sion of pulmonary neutrophil recmitrnent

Porting and refurbishment of the WSS TNG control software

NASA Astrophysics Data System (ADS)

Caproni, Alessandro; Zacchei, Andrea; Vuerli, Claudio; Pucillo, Mauro

2004-09-01

The Workstation Software Sytem (WSS) is the high level control software of the Italian Galileo Galilei Telescope settled in La Palma Canary Island developed at the beginning of '90 for HP-UX workstations. WSS may be seen as a middle layer software system that manages the communications between the real time systems (VME), different workstations and high level applications providing a uniform distributed environment. The project to port the control software from the HP workstation to Linux environment started at the end of 2001. It is aimed to refurbish the control software introducing some of the new software technologies and languages, available for free in the Linux operating system. The project was realized by gradually substituting each HP workstation with a Linux PC with the goal to avoid main changes in the original software running under HP-UX. Three main phases characterized the project: creation of a simulated control room with several Linux PCs running WSS (to check all the functionality); insertion in the simulated control room of some HPs (to check the mixed environment); substitution of HP workstation in the real control room. From a software point of view, the project introduces some new technologies, like multi-threading, and the possibility to develop high level WSS applications with almost every programming language that implements the Berkley sockets. A library to develop java applications has also been created and tested.

Inverse scattering transform for the KPI equation on the background of a one-line soliton*Inverse scattering transform for the KPI equation on the background of a one-line soliton

NASA Astrophysics Data System (ADS)

Fokas, A. S.; Pogrebkov, A. K.

2003-03-01

We study the initial value problem of the Kadomtsev-Petviashvili I (KPI) equation with initial data u(x1,x2,0) = u1(x1)+u2(x1,x2), where u1(x1) is the one-soliton solution of the Korteweg-de Vries equation evaluated at zero time and u2(x1,x2) decays sufficiently rapidly on the (x1,x2)-plane. This involves the analysis of the nonstationary Schrödinger equation (with time replaced by x2) with potential u(x1,x2,0). We introduce an appropriate sectionally analytic eigenfunction in the complex k-plane where k is the spectral parameter. This eigenfunction has the novelty that in addition to the usual jump across the real k-axis, it also has a jump across a segment of the imaginary k-axis. We show that this eigenfunction can be reconstructed through a linear integral equation uniquely defined in terms of appropriate scattering data. In turn, these scattering data are uniquely constructed in terms of u1(x1) and u2(x1,x2). This result implies that the solution of the KPI equation can be obtained through the above linear integral equation where the scattering data have a simple t-dependence.

Synergistic anti-Campylobacter jejuni activity of fluoroquinolone and macrolide antibiotics with phenolic compounds

PubMed Central

Oh, Euna; Jeon, Byeonghwa

2015-01-01

The increasing resistance of Campylobacter to clinically important antibiotics, such as fluoroquinolones and macrolides, is a serious public health problem. The objective of this study is to investigate synergistic anti-Campylobacter jejuni activity of fluoroquinolones and macrolides in combination with phenolic compounds. Synergistic antimicrobial activity was measured by performing a checkerboard assay with ciprofloxacin and erythromycin in the presence of 21 phenolic compounds. Membrane permeability changes in C. jejuni by phenolic compounds were determined by measuring the level of intracellular uptake of 1-N-phenylnaphthylamine (NPN). Antibiotic accumulation assays were performed to evaluate the level of ciprofloxacin accumulation in C. jejuni. Six phenolic compounds, including p-coumaric acid, sinapic acid, caffeic acid, vanillic acid, gallic acid, and taxifolin, significantly increased the susceptibility to ciprofloxacin and erythromycin in several human and poultry isolates. The synergistic antimicrobial effect was also observed in ciprofloxacin- and erythromycin-resistant C. jejuni strains. The phenolic compounds also substantially increased membrane permeability and antibiotic accumulation in C. jejuni. Interestingly, some phenolic compounds, such as gallic acid and taxifolin, significantly reduced the expression of the CmeABC multidrug efflux pump. Phenolic compounds increased the NPN accumulation in the cmeB mutant, indicating phenolic compounds may affect the membrane permeability. In this study, we successfully demonstrated that combinational treatment of C. jejuni with antibiotics and phenolic compounds synergistically inhibits C. jejuni by impacting both antimicrobial influx and efflux. PMID:26528273

Kinematics of the CSE in VY CMa

NASA Astrophysics Data System (ADS)

Choi, Yoon Kyung

2009-07-01

We report on astrometric results of H2O and SiO masers in the circumstellar envelopes of VY Canis Majoris (VY CMa) carried out with VERA for 2 years. Absolute positions and proper motions of 3 different frequencies of masers were measured with phase-referencing analyses. Using the positions and the 3-dimensional velocities of the masers, we considered the 3-dimensional structures and kinematics of the circumstellar envelopes around VY CMa. The H2O masers show bipolar outflow along the line of sight, and the SiO masers have both expanding and contracting motions with less than 5 km/s.

Dust-forming molecules in VY Canis Majoris (and Betelgeuse)

NASA Astrophysics Data System (ADS)

Kamiński, T.; Gottlieb, C. A.; Schmidt, M. R.; Patel, N. A.; Young, K. H.; Menten, K. M.; Brünken, S.; Müller, H. S. P.; Winters, J. M.; McCarthy, M. C.

2013-05-01

The formation of inorganic dust in circumstellar environments of evolved stars is poorly understood. Spectra of molecules thought to be most important for the nucleation, i.e. AlO, TiO, and TiO2, have been recently detected in the red supergiant VY CMa. These molecules are effectively formed in VY CMa and the observations suggest that non-equilibrium chemistry must be involved in their formation and nucleation into dust. In addition to exploring the recent observations of VY CMa, we briefly discuss the possibility of detecting these molecules in the "dust-poor" circumstellar environment of Betelgeuse.

Maser observation in VY CMa with VERA

NASA Astrophysics Data System (ADS)

Choi, Yoon Kyung

We present the results of multi-epoch VERA (VLBI Exploration of Radio Astrometry) observations of H2O masers at 22 GHz and ^28SiO masers at 43 GHz in the supergiant VY Canis Majoris (hereafter, VY CMa). We estimate the inner motion of H2O masers over 6 months and that of SiO masers over 1 month. Using the inner motion, we calculated the statistical parallax of VY CMa. The size of the emitting region for ^28SiO masers is R_SiO ~1.81-2.89 R_* and it is consistent with the previous study.

Radio Photosphere and Mass-Loss Envelope of VY Canis Majoris

NASA Astrophysics Data System (ADS)

Lipscy, S. J.; Jura, M.; Reid, M. J.

2005-06-01

We have used the VLA to detect emission from the supergiant VY CMa at radio wavelengths and have constructed 3000-4500 K isothermal outer atmospheres constrained by the data. These models produce a radio photosphere at 1.5-2 R*. An extrapolation of the model can account for the observed total mass-loss rate of the star. We also present mid-infrared imaging of the supergiant which suggests that warm dust is extended in the same direction as the near-infrared reflection nebula around VY CMa. The origin of the asymmetries in the outflow remains an unsolved problem.

Erratum: ``Interferometric Observation of the Highly Polarized SiO Maser Emission from the v = 1, J = 5-4 Transition Associated with VY Canis Majoris'' (ApJ, 616, L47 [2004])

NASA Astrophysics Data System (ADS)

Shinnaga, Hiroko; Moran, James M.; Young, Ken H.; Ho, Paul T. P.

2004-12-01

Because of an error in transferring proof corrections, units for the 310 GHz flux were incorrectly given in Jy instead of mJy in § 3.3 of this Letter. In the first paragraph of § 3.3, the fourth sentence should correctly read: ``The fluxes at 301 and 658 GHz measured with the SMA recently were 340+/-10 mJy and 7.8+/-2.6 Jy, respectively.'' The Press sincerely regrets this error.

Quantum corrections to quasi-periodic solution of Sine-Gordon model and periodic solution of phi4 model

NASA Astrophysics Data System (ADS)

Kwiatkowski, G.; Leble, S.

2014-03-01

Analytical form of quantum corrections to quasi-periodic solution of Sine-Gordon model and periodic solution of phi4 model is obtained through zeta function regularisation with account of all rest variables of a d-dimensional theory. Qualitative dependence of quantum corrections on parameters of the classical systems is also evaluated for a much broader class of potentials u(x) = b2f(bx) + C with b and C as arbitrary real constants.

Image Compression Research.

DTIC Science & Technology

1981-08-01

FOR THE COI4MANDER:9P 4 4:JOHN P. HUSS Acting Chief, Plans Office If your address has changed or if you wish to be removed from the .RADC mailing list...these transformations are not sensitive to changes in local image characteristics, and so may work much better on some image blocks than on others. The...i,j=l i n i j=1 ij The feature u(x) is a good measure of bloc’, " busyness " and for this reason provides a high correlation with block information

Proceedings of the 13th Army Symposium on Solid Mechanics, 17-19 August 1993, Plymouth, Massachusetts.

DTIC Science & Technology

1993-01-01

the material relating the average stresses Ux(= Uz) to the eigenstrains e * is (Mallick and Krajcinovic, 1992a,b) 21 (yt)+ (p), 2 d-x(y, s) +R3 (y, s... eigenstrain in the material due to chemical shrinkage and thermal dilatation. During the chemical reaction of bonding two reacting monomers must reduce their...reaction (3) and connectivity dependent material properties and eigenstrains (4). However, the most prominent source of complexity is the fact that the

Periodic Solutions of Prescribed Energy for a Class of Hamiltonian Systems.

DTIC Science & Technology

1984-09-01

near ag1+2d’ e.g. X(x) ( C, (3.6) IU(x) - U(;)I e. PIuq (;)12 + o(q) 4 K2 PLq Now for £(x) 4 C, by ($3) and (3.6), -2 V(x) - (U(x) - (1 + 2d)) - 2...H(z(t)) E constant so ’(z) - 1 implies that z(t) e D. Lastly since A 0 0, making the change of time scale t + AtI shows z is a 2irA periodic solution

Capillary surfaces in a wedge: Differing contact angles

NASA Technical Reports Server (NTRS)

Concus, Paul; Finn, Robert

1994-01-01

The possible zero-gravity equilibrium configurations of capillary surfaces u(x, y) in cylindrical containers whose sections are (wedge) domains with corners are investigated mathematically, for the case in which the contact angles on the two sides of the wedge may differ. In such a situation the behavior can depart in significant qualitative ways from that for which the contact angles on the two sides are the same. Conditions are described under which such qualitative changes must occur. Numerically computed surfaces are depicted to indicate the behavior.

Fixed Wing Performance. Theory and Flight Test Techniques

DTIC Science & Technology

1977-07-01

L , J JA , iii hit I.IbS*I u Se t UX 1-4, Xl -4 TEST PROCEDURES AND TECHTNIUE,_ Pertinent Particulars a. At the time these tests are performed, the...7 , - • • . • • • • ••: • - • • -V• ,• • • • . . . REFERENCES Section XV 1. Anthropometry of Naval Aviators, 1964, NAEC-ACEL--533. 2. Cockpit...glare shlelds, etc. Htuman e~gineering persokmet are prepared to se particuiar equipments to attain quarititative data in cockpi’ anthropometry N NOT

Measurements of Ocean Surface Turbulence and Wave-Turbulence Interactions (PREPRINT)

DTIC Science & Technology

2008-02-19

measurements described here were obtained from a Þeld experiment conducted from R /P 1In the case of gas transfer, these molecular layers can also be at the...ßux data. The eddy covariance sys- tem included a three-axis anemometer/thermometer (Campbell CSAT 3), an open path infrared hygrometer/CO2 sensor...boom of R /P FLIP approximately 18 m from the hull at an elevation of 13 m above mean sea level (MSL). The infrared optical system was set-up with the

Comparative Spectra of Oxygen-Rich Versus Carbon-Rich Circumstellar Shells: VY Canis Majoris and IRC(plus)10216 at 215-285 GHz

NASA Technical Reports Server (NTRS)

Tenebaum, E. D.; Dodd, J. L.; Milam, S. N.; Woolf, N. J.; Ziurys, L. M.

2010-01-01

A sensitive (1sigma rms at 1 MHz resolution approx.3 mK) 1 mm spectral line survey (214.5-285.5 GHz) of VY Canis Majoris (VY CMa) and IRC +10216 has been conducted to compare the chemistries of oxygen- and carbon-rich circumstellar envelopes. This study was carried out using the Submillimeter Telescope of the Arizona Radio Observatory with a new Atacama Large Millimeter Array type receiver. This survey is the first to chemically characterize an O-rich circumstellar shell at millimeter wavelengths. In VY CMa, 128 emission features were detected arising from 18 different molecules; and in IRC +10216, 720 lines were observed, assigned to 32 different species. The 1 mm spectrum of VY CMa is dominated by SO, and SiS; in IRC +10216, C4H and SiC2 are the most recurrent species. Ten molecules were common to both sources: CO, SiS, SiO, CS, CN, HCN, HNC, NaCl, PN, and HCO(+). Sulfur plays an important role in VY CMa, but saturated/ unsaturated carbon dominates the molecular content of IRC +102.16, producing CH2NH, for example. Although the molecular complexity of IRC +10216 is greater, VY CMa supports a unique "inorganic" chemistry leading to the oxides PO, AlO, and AlOH. Only diatomic and triatomic compounds were observed in VY CMa, while species with four or more atoms are common in IRC +10216, reflecting carbon's ability to form multiple strong bonds, unlike oxygen. In VY CMa, a new water maser (v2 = 2) has been found, as well as vibrationally excited NaCl. Toward IRC +10216, vibrationally excited CCH was detected for the first time.

Hubble's Cosmic Bubbles

NASA Image and Video Library

2017-12-08

This entrancing image shows a few of the tenuous threads that comprise Sh2-308, a faint and wispy shell of gas located 5,200 light-years away in the constellation of Canis Major (The Great Dog). Sh2-308 is a large bubble-like structure wrapped around an extremely large, bright type of star known as a Wolf-Rayet Star — this particular star is called EZ Canis Majoris. These type of stars are among the brightest and most massive stars in the Universe, tens of times more massive than our own sun, and they represent the extremes of stellar evolution. Thick winds continually poured off the progenitors of such stars, flooding their surroundings and draining the outer layers of the Wolf-Rayet stars. The fast wind of a Wolf-Rayet star therefore sweeps up the surrounding material to form bubbles of gas. EZ Canis Majoris is responsible for creating the bubble of Sh2-308 — the star threw off its outer layers to create the strands visible here. The intense and ongoing radiation from the star pushes the bubble out farther and farther, blowing it bigger and bigger. Currently the edges of Sh2-308 are some 60 light-years apart! Beautiful as these cosmic bubbles are, they are fleeting. The same stars that form them will also cause their death, eclipsing and subsuming them in violent supernova explosions. Credit: ESA/Hubble & NASA NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Oxygen-rich Mass Loss with a Pinch of Salt: NaCl in the Circumstellar Gas of IK Tauri and VY Canis Majoris

NASA Astrophysics Data System (ADS)

Milam, S. N.; Apponi, A. J.; Woolf, N. J.; Ziurys, L. M.

2007-10-01

The NaCl molecule has been observed in the circumstellar envelopes of VY Canis Majoris (VY CMa) and IK Tauri (IK Tau)-the first identifications of a metal refractory in oxygen-rich shells of evolved stars. Five rotational transitions of NaCl at 1 and 2 mm were detected toward VY CMa and three 1 mm lines were observed toward IK Tau, using the telescopes of the Arizona Radio Observatory. In both objects, the line widths of the NaCl profiles were extremely narrow relative to those of other molecules, indicating that sodium chloride has not reached the terminal outflow velocity in either star, likely a result of early condensation onto grains. Modeling the observed spectra suggests abundances, relative to H2, of f~5×10-9 in VY CMa and f~4×10-9 in IK Tau, with source sizes of 0.5" and 0.3", respectively. The extent of these sources is consistent with the size of the dust acceleration zones in both stars. NaCl therefore appears to be at least as abundant in O-rich shells as compared to C-rich envelopes, where f~(0.2-2)×10-9, although it appears to condense out earlier in the O-rich case. Chemical equilibrium calculations indicate that NaCl is the major carrier of sodium at T~1100 K for oxygen-rich stars, with predicted fractional abundances in good agreement with the observations. These measurements suggest that crystalline salt may be an important condensate for sodium in both C- and O-rich circumstellar shells.

Sulfur Chemistry in the Envelope of VY Canis Majoris: Detailed Analysis of SO and SO2 Emission

NASA Astrophysics Data System (ADS)

Adande, G. R.; Edwards, J. L.; Ziurys, L. M.

2013-11-01

Detailed radiative transfer modeling has been carried out for SO2 and SO originating in the envelope of the O-rich supergiant star VY Canis Majoris (VY CMa). A total of 27 transitions of SO2 and 7 transitions of SO lying in the energy range 3.0-138.2 cm-1 were analyzed using a new non-LTE radiative transfer code that incorporates non-spherical geometries. The spectra were primarily obtained from the Arizona Radio Observatory (ARO) 1 mm spectral survey of VY CMa, conducted with the Submillimeter Telescope; additional lines were measured with the ARO 12 m antenna at 2 and 3 mm. SO2 and SO were found to arise from five distinct outflows within the envelope, four which are asymmetric with respect to the star. Three flows arise from high-velocity red-shifted material, one from a blue-shifted wind, and the final from a classic "spherical" expansion. In the spherical component, the peak fractional abundance, relative to H2, of both molecules is f ~ 2.5 × 10-7 at r ~ 25 R *, and steadily decreases outward. SO2 appears to be a "parent" molecule, formed near the stellar photosphere. In the asymmetric outflows, both SO and SO2 are more prominent at large stellar radii in dense (106-107 cm-3), clumpy material, achieving their maximum abundance between 200 and 600 R * with f ~ 3.0 × 10-8-1.5 × 10-7. These results suggest that in the collimated outflows, both species are either produced by shock chemistry or are remnant inner shell material swept up in the high-velocity winds.

Comparative Spectra of Oxygen-rich Versus Carbon-rich Circumstellar Shells: VY Canis Majoris and IRC +10216 at 215-285 GHz

NASA Astrophysics Data System (ADS)

Tenenbaum, E. D.; Dodd, J. L.; Milam, S. N.; Woolf, N. J.; Ziurys, L. M.

2010-09-01

A sensitive (1σ rms at 1 MHz resolution ~3 mK) 1 mm spectral line survey (214.5-285.5 GHz) of VY Canis Majoris (VY CMa) and IRC +10216 has been conducted to compare the chemistries of oxygen- and carbon-rich circumstellar envelopes. This study was carried out using the Submillimeter Telescope of the Arizona Radio Observatory with a new Atacama Large Millimeter Array type receiver. This survey is the first to chemically characterize an O-rich circumstellar shell at millimeter wavelengths. In VY CMa, 128 emission features were detected arising from 18 different molecules; and in IRC +10216, 720 lines were observed, assigned to 32 different species. The 1 mm spectrum of VY CMa is dominated by SO2 and SiS; in IRC +10216, C4H and SiC2 are the most recurrent species. Ten molecules were common to both sources: CO, SiS, SiO, CS, CN, HCN, HNC, NaCl, PN, and HCO+. Sulfur plays an important role in VY CMa, but saturated/unsaturated carbon dominates the molecular content of IRC +10216, producing CH2NH, for example. Although the molecular complexity of IRC +10216 is greater, VY CMa supports a unique "inorganic" chemistry leading to the oxides PO, AlO, and AlOH. Only diatomic and triatomic compounds were observed in VY CMa, while species with four or more atoms are common in IRC +10216, reflecting carbon's ability to form multiple strong bonds, unlike oxygen. In VY CMa, a new water maser (v 2 = 2) has been found, as well as vibrationally excited NaCl. Toward IRC +10216, vibrationally excited CCH was detected for the first time.

Strong magnetic field generated by the extreme oxygen-rich red supergiant VY Canis Majoris

NASA Astrophysics Data System (ADS)

Shinnaga, Hiroko; Claussen, Mark J.; Yamamoto, Satoshi; Shimojo, Masumi

2017-12-01

Evolved stars experience high mass-loss rates forming thick circumstellar envelopes (CSEs). The circumstellar material is made of the result of stellar nucleosynthesis and, as such, plays a crucial role in the chemical evolution of galaxies and the universe. Since asymmetric geometries of CSEs are common, and with very complex structures for some cases, radiative pressure from the stars can explain only a small portion of the mass-loss processes; thus the essential driving mechanism is still unknown, particularly for high-mass stars. Here we report on magnetic field measurements associated with the well-known extreme red supergiant (RSG) VY Canis Majoris (VY CMa). We measured the linear polarization and the Zeeman splitting of the SiO v = 0, J = 1-0 transition using a sensitive radio interferometer. The measured magnetic field strengths are surprisingly high; their upper limits range between 150 and 650 G within 530 au (˜80 R*) of the star. The lower limit of the field strength is expected to be at least ˜10 G based on the high degree of linear polarization. Since the field strengths are very high, the magnetic field must be a key element in understanding the stellar evolution of VY CMa, as well as the dynamical and chemical evolution of the complex CSE of the star. M-type RSGs, with large stellar surface, were thought to be very slow rotators. This would seem to make a dynamo in operation difficult, and would also dilute any fossil magnetic field. At least for VY CMa, we expect that powerful dynamo processes must still be active to generate the intense magnetic field.

Exotic Metal Molecules in Oxygen-rich Envelopes: Detection of AlOH (X1Σ+) in VY Canis Majoris

NASA Astrophysics Data System (ADS)

Tenenbaum, E. D.; Ziurys, L. M.

2010-03-01

A new interstellar molecule, AlOH, has been detected toward the envelope of VY Canis Majoris (VY CMa), an oxygen-rich red supergiant. Three rotational transitions of AlOH were observed using the facilities of the Arizona Radio Observatory (ARO). The J = 9 → 8 and J = 7 → 6 lines at 1 mm were measured with the ARO Submillimeter Telescope, while the J = 5 → 4 transition at 2 mm was observed with the ARO 12 m antenna on Kitt Peak. The AlOH spectra exhibit quite narrow line widths of 16-23 km s-1, as found for NaCl in this source, indicating that the emission arises from within the dust acceleration zone of the central circumstellar outflow. From a radiative transfer analysis, the abundance of AlOH relative to H2 was found to be ~1 × 10-7 for a source size of 0.26'' or 22 R* . In contrast, AlCl was not detected with f <= 5 × 10-8. AlOH is likely formed just beyond the photosphere via thermodynamic equilibrium chemistry and then disappears due to dust condensation. The AlOH/AlO abundance ratio found in VY CMa is ~17. Therefore, AlOH appears to be the dominant gas-phase molecular carrier of aluminum in this oxygen-rich shell. Local thermodynamic equilibrium calculations predict that the monohydroxides should be the major carriers of Al, Ca, and Mg in O-rich envelopes, as opposed to the oxides or halides. The apparent predominance of aluminum-bearing molecules in VY CMa may reflect proton addition processes in H-shell burning.

Probing Hypergiant Mass Loss with Adaptive Optics Imaging and Polarimetry in the Infrared: MMT-Pol and LMIRCam Observations of IRC +10420 and VY Canis Majoris

NASA Astrophysics Data System (ADS)

Shenoy, Dinesh P.; Jones, Terry J.; Packham, Chris; Lopez-Rodriguez, Enrique

2015-07-01

We present 2-5 μm adaptive optics (AO) imaging and polarimetry of the famous hypergiant stars IRC +10420 and VY Canis Majoris. The imaging polarimetry of IRC +10420 with MMT-Pol at 2.2 μ {m} resolves nebular emission with intrinsic polarization of 30%, with a high surface brightness indicating optically thick scattering. The relatively uniform distribution of this polarized emission both radially and azimuthally around the star confirms previous studies that place the scattering dust largely in the plane of the sky. Using constraints on scattered light consistent with the polarimetry at 2.2 μ {m}, extrapolation to wavelengths in the 3-5 μm band predicts a scattered light component significantly below the nebular flux that is observed in our Large Binocular Telescope/LMIRCam 3-5 μm AO imaging. Under the assumption this excess emission is thermal, we find a color temperature of ˜500 K is required, well in excess of the emissivity-modified equilibrium temperature for typical astrophysical dust. The nebular features of VY CMa are found to be highly polarized (up to 60%) at 1.3 μm, again with optically thick scattering required to reproduce the observed surface brightness. This star’s peculiar nebular feature dubbed the “Southwest Clump” is clearly detected in the 3.1 μm polarimetry as well, which, unlike IRC +10420, is consistent with scattered light alone. The high intrinsic polarizations of both hypergiants’ nebulae are compatible with optically thick scattering for typical dust around evolved dusty stars, where the depolarizing effect of multiple scatters is mitigated by the grains’ low albedos. Observations reported here were obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona.

Quasar Host Galaxies/Neptune Rotation/Galaxy Building Blocks/Hubble Deep Field/Saturn Storm

NASA Technical Reports Server (NTRS)

2001-01-01

Computerized animations simulate a quasar erupting in the core of a normal spiral galaxy, the collision of two interacting galaxies, and the evolution of the universe. Hubble Space Telescope (HST) images show six quasars' host galaxies (including spirals, ellipticals, and colliding galaxies) and six clumps of galaxies approximately 11 billion light years away. A false color time lapse movie of Neptune displays the planet's 16-hour rotation, and the evolution of a storm on Saturn is seen though a video of the planet's rotation. A zoom sequence starts with a ground-based image of the constellation Ursa major and ends with the Hubble Deep Field through progressively narrower and deeper views.

Hybrid Coatings Enriched with Tetraethoxysilane for Corrosion Mitigation of Hot-Dip Galvanized Steel in Chloride Contaminated Simulated Concrete Pore Solutions

PubMed Central

Figueira, Rita B.; Callone, Emanuela; Silva, Carlos J. R.; Pereira, Elsa V.; Dirè, Sandra

2017-01-01

Hybrid sol-gel coatings, named U(X):TEOS, based on ureasilicate matrices (U(X)) enriched with tetraethoxysilane (TEOS), were synthesized. The influence of TEOS addition was studied on both the structure of the hybrid sol-gel films as well as on the electrochemical properties. The effect of TEOS on the structure of the hybrid sol-gel films was investigated by solid state Nuclear Magnetic Resonance. The dielectric properties of the different materials were investigated by electrochemical impedance spectroscopy. The corrosion behavior of the hybrid coatings on HDGS was studied in chloride-contaminated simulated concrete pore solutions (SCPS) by polarization resistance measurements. The roughness of the HDGS coated with hybrids was also characterized by atomic force microscopy. The structural characterization of the hybrid materials proved the effective reaction between Jeffamine® and 3-isocyanate propyltriethoxysilane (ICPTES) and indicated that the addition of TEOS does not seem to affect the organic structure or to increase the degree of condensation of the hybrid materials. Despite the apparent lack of influence on the hybrids architecture, the polarization resistance measurements confirmed that TEOS addition improves the corrosion resistance of the hybrid coatings (U(X):TEOS) in chloride-contaminated SCPS when compared to samples prepared without any TEOS (U(X)). This behavior could be related to the decrease in roughness of the hybrid coatings (due TEOS addition) and to the different metal coating interaction resulting from the increase of the inorganic component in the hybrid matrix. PMID:28772667

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

Cherdyntsev, V.V.; Kazachevskii, I.V.; Kuzmina, E.A.

The ratio of Th isotopes (Io,/sup -/UX/sub 1/, Th/sup 232/, RdTh) and U isotopes (U/sup 234/ and U/sup 238/) in natural waters, fossil bones, and soils, as well as in shells of fresh-water mollusks of the Paleolithic site Molodovo and other areas of the Dniester foreland was investigated. In the waters of Molodovo are distinguished waters of neogenic limestones with a low value of gamma =U/sup 234//U/sup 238/ = 10.3 x 10.5 and waters of the Paleozoic: gamma = 1.34, apparently feeding the quarternary stratum. The mineralization of fossil bones was realized in the Upper Paleolith by waters with lowmore » values and in the Middle Paleolith by waters with high gamma -values. Uranium migration was confirmed by the investigation of the radioelement ratios in fossil bones of the sites Molodovo I and Molodovo V. This process apparently did not affect the Mousterian layers of the site Molodovo V, so that the age of the layers, according to Io/UX/sub 1/ and gamma , equaling 130 thousand years, is near to the truth. The age of the fossil soil of the lower horizon of Molodovo I (end of Riss -RissWurm) is more than 260 thousand years. In the shells of fresh-water mollusks an intensive migration of U and Ra isotopes occurs For example, an exceptional high value RdTh/Th = 12.3 450 deg C in a 0.9 (activity units) was obtained. (auth)« less

Belowground Response to Drought in a Tropical Forest Soil. II. Change in Microbial Function Impacts Carbon Composition

PubMed Central

Bouskill, Nicholas J.; Wood, Tana E.; Baran, Richard; Hao, Zhao; Ye, Zaw; Bowen, Ben P.; Lim, Hsiao Chien; Nico, Peter S.; Holman, Hoi-Ying; Gilbert, Benjamin; Silver, Whendee L.; Northen, Trent R.; Brodie, Eoin L.

2016-01-01

Climate model projections for tropical regions show clear perturbation of precipitation patterns leading to increased frequency and severity of drought in some regions. Previous work has shown declining soil moisture to be a strong driver of changes in microbial trait distribution, however, the feedback of any shift in functional potential on ecosystem properties related to carbon cycling are poorly understood. Here we show that drought-induced changes in microbial functional diversity and activity shape, and are in turn shaped by, the composition of dissolved and soil-associated carbon. We also demonstrate that a shift in microbial functional traits that favor the production of hygroscopic compounds alter the efflux of carbon dioxide following soil rewetting. Under drought the composition of the dissolved organic carbon pool changed in a manner consistent with a microbial metabolic response. We hypothesize that this microbial ecophysiological response to changing soil moisture elevates the intracellular carbon demand stimulating extracellular enzyme production, that prompts the observed decline in more complex carbon compounds (e.g., cellulose and lignin). Furthermore, a metabolic response to drought appeared to condition (biologically and physically) the soil, notably through the production of polysaccharides, particularly in experimental plots that had been pre-exposed to a short-term drought. This hysteretic response, in addition to an observed drought-related decline in phosphorus concentration, may have been responsible for a comparatively modest CO2 efflux following wet-up in drought plots relative to control plots. PMID:27014243

Evidence for Stable v = 0, j = 1 → 0 SiO Maser Emission from VY Canis Majoris

NASA Astrophysics Data System (ADS)

McIntosh, G. C.; Rislow, B.

2009-02-01

Observations of the SiO v = 0, J = 1 → 0 spectra from VY CMa from 2003 through 2006 indicate an unusually long-lived, highly linearly polarized maser emission at a V lsr of approximately 18.5 km s-1. A time series cross-correlation analysis has been developed for calculating the characteristic lifetime of linearly polarized spectra. Applying the cross-correlation to these spectra indicates a characteristic lifetime of 5600 ± 400 days. These emission characteristics may be generated in a region of relatively stable outflow geometry and magnetic field rather than in the more ephemeral circumstellar environment.

An infrared upconverter for astronomical imaging

NASA Technical Reports Server (NTRS)

Boyd, R. W.; Townes, C. H.

1977-01-01

An imaging upconverter has been constructed which is suitable for use in the study of the thermal 10-micron radiation from astronomical sources. The infrared radiation is converted to visible radiation by mixing in a 1-cm-long proustite crystal. The phase-matched 2-kayser bandpass is tunable from 9 to 11 microns. The conversion efficiency is 2 by 10 to the -7th power and the field of view of 40 arc seconds on the sky contains several hundred picture elements, approximately diffraction-limited resolution in a large telescope. The instrument has been used in studies of the sun, moon, Mercury, and VY Canis Majoris.

Deformation Analyses and Lithologic Characterization in Overpressured Basins Based on Logging While Drilling and Wireline Results from the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Iturrino, G. J.; Pirmez, C.; Moore, J. C.; Reichow, M. K.; Dugan, B. E.; Sawyer, D. E.; Flemings, P. B.; Shipboard Scientific Party, I.

2005-12-01

IODP Expedition 308 drilled transects along the Brazos-Trinity IV and Ursa Basins in the western and eastern Gulf of Mexico, respectively, for examining how sedimentation, overpressure, fluid flow, and deformation are coupled in passive margin settings. A total of eight holes were logged using either logging while drilling (LWD) or wireline techniques to evaluate the controls on slope stability, understand the timing of sedimentation and slumping, establish the petrophysical properties of shallow sediments, and provide a better understanding of turbidite systems. Overall, the log responses vary for the different lithostratigraphic units and associated regional seismic reflectors. The data acquired also make bed-to-bed correlation between sites possible, which is valuable for the study of sandy turbidites and studies of regional deformation. The thick sedimentary successions drilled at these basins show records of the evolution of channel-levee systems composed of low relief channels that were incapable of confining the turbidity currents causing an overspill of sand and silt. In addition, mass transport deposits at shallow depths, and transitions between interbedded silt, sand, and mud units are common features identified in many of the downhole logging data. In the Ursa Basin sediments, resistivity-at-the-bit images show significant deformation of the overlying hemipelagic drape and distal turbidites that were drilled in these areas. Numerous dipping beds throughout these intervals with dips ranging from 5 to 55 degrees confirm core observations. Steeply deformed beds, with dips as high as 65 degrees, and folded and faulted beds suggest down slope remobilization as mass-transport deposits. Resistivity images also show evidence of these mass-transport deposits where steep dips and folds suggest the presence of overturned beds within a series of cyclic intervals that we interpret as a succession of sand-silt-mud lamina. Preliminary structural analyses suggest that many of the deformation features trend in an E-W direction with the majority dipping to the north.

Overview of the evolution of clay mineralogy in the Gulf of Mexico: implications for regional climate and drainage history of the Mississippi and Brazos-Trinity Rivers

NASA Astrophysics Data System (ADS)

Adatte, T.; John, C. M.; Flemings, P. B.; Behrmann, J.

2005-12-01

In this paper we present the overview and preliminary results of the analysis of clay minerals in two mini basins drilled during IODP Expedition 308. The goal of our project is to explore the vertical and temporal trends in clay mineralogy in the Ursa Basin and the Brazos-Trinity basin #4. The Brazos-Trinity basin was the sink for sands and clays carried by the Brazos and Trinity Rivers, while the Ursa basin was the sink for sediments carried by the Mississippi river. Reconstructing clay minerals (phyllosilicates <2μm in size) accumulations at these locations could thus potentially yield information on changes in the transport and the source of the siliclastic material transported in the course of the Pleistocene by these three rivers. Moreover, because the type of clay formed in soils through weathering processes largely depend on temperature and amount of precipitation, the dataset generated could provide clues on past climate changes. Some of the mechanisms that are hypothesized to play a major role in controlling clay accumulation in the basins investigated are reworking of clays on the American continent (controlled at the time-scale investigated here by changes in precipitation) and turbidity current deposition (controlled mainly by sea-level changes and thus glacio-eustasy). Finally, a major focusing point of Expedition 308 was sediment physical properties in an overpressured basin. Because each clay mineral specie has a specific average grain sizes, physical properties and cation exchange capacity, the clay mineral composition of the sediment investigated here (dominated by clay-sized particles) may partly control how these sediments react to changes in pressure and temperature. Thus, clay mineral data could contribute to our understanding of the physical properties of the sediments in overpressured basins, and collaborations with geotechnical scientist are planned.

The formation of the Milky Way halo and its dwarf satellites; a NLTE-1D abundance analysis. I. Homogeneous set of atmospheric parameters

NASA Astrophysics Data System (ADS)

Mashonkina, L.; Jablonka, P.; Pakhomov, Yu.; Sitnova, T.; North, P.

2017-08-01

We present a homogeneous set of accurate atmospheric parameters for a complete sample of very and extremely metal-poor stars in the dwarf spheroidal galaxies (dSphs) Sculptor, Ursa Minor, Sextans, Fornax, Boötes I, Ursa Major II, and Leo IV. We also deliver a Milky Way (MW) comparison sample of giant stars covering the - 4 < [Fe/H] < - 1.7 metallicity range. We show that, in the [Fe/H] ≿ - 3.7 regime, the non-local thermodynamic equilibrium (NLTE) calculations with non-spectroscopic effective temperature (Teff) and surface gravity (log g) based on the photometric methods and known distance provide consistent abundances of the Fe I and Fe II lines. This justifies the Fe I/Fe II ionisation equilibrium method to determine log g for the MW halo giants with unknown distance. The atmospheric parameters of the dSphs and MW stars were checked with independent methods. In the [Fe/H] > - 3.5 regime, the Ti I/Ti II ionisation equilibrium is fulfilled in the NLTE calculations. In the log g - Teff plane, all the stars sit on the giant branch of the evolutionary tracks corresponding to [Fe/H] = - 2 to - 4, in line with their metallicities. For some of the most metal-poor stars of our sample, we achieve relatively inconsistent NLTE abundances from the two ionisation stages for both iron and titanium. We suggest that this is a consequence of the uncertainty in the Teff-colour relation at those metallicities. The results of this work provide the basis for a detailed abundance analysis presented in a companion paper. Tables A.1 and A.2 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/604/A129

Searching for Flickering Giants in the Ursa Minor Dwarf Spheroidal Galaxy

NASA Astrophysics Data System (ADS)

Montiel, Edward J.; Mighell, K. J.

2010-01-01

We present a preliminary analysis of three epochs of archival Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) observations of a single field in the Ursa Minor (UMi) dwarf spheroidal (dSph) galaxy. These observations were obtained in 2000, 2002, and 2004 (GO-7341, GO-8776, GO-2004; PI: Olszewski). We expand upon the work of Mighell and Roederer 2004 who reported the existence of low-amplitude variability in red giant stars in the UMi dSph. We report the 16 brightest point sources (F606W <= 21.5 mag) that we are able to match between all 3 epochs. The 112 observations were analyzed with HSTphot. We tested for variability with a chi-squared statistic that had a softened photometric error where 0.01 mag was added in quadrature to the reported HSTphot photometric error. We find that all 13 stars and 3 probable galaxies exhibit the same phenomenon as described in Mighell and Roederer with peak to peak amplitudes ranging from 54 to 125 mmags on 10 minute timescales. If these objects were not varying, the deviates should be normally distributed. However, we find that the deviates have a standard deviation of 1.4. This leads to three possible conclusions: (1) the observed phenomenon is real, (2) an additional systematic error of 7 mmag needs to be added to account for additional photometric errors (possibly due to dithering), or (3) there was a small instrumental instability with the WFPC2 instrument from 2000 to 2004. E.J.M. was supported by the NOAO/KPNO Research Experience for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program and the Department of Defense ASSURE program through Scientific Program Order No. 13 (AST-0754223) of the Cooperative Agreement No.AST-0132798 between the Association of Universities for Research in Astronomy (AURA) and the NSF.

Understanding space science under the northern lights

NASA Astrophysics Data System (ADS)

Koskinen, H.

What is space science? The answers to this question can be very variable indeed. In fact, space research is a field where science, technology, and applications are so closely tied together that it is often difficult to recognize the central role of science. However, as paradoxical as it may sound, it appears that the less-educated public often appreciates the value of space science better than highly educated policy makers and bureaucrats who tend to evaluate the importance of space activities in terms of economic and societal benefits only. In a country like Finland located below the zone, where auroras are visible during the long dark winter nights, the space is perhaps closer to the public than in countries where the visible objects are the Moon, planets and stars somewhere far away. This positive fact has been very useful, for example, in popularization of such an abstract concept as space weather. In Finland it is possible to see space weather and this rises the curiosity about the processes behind this magnificent phenomenon. Of course, also in Finland the beautiful SOHO images of the Sun and the Hubble Space Telescope pictures of the remote universe attract the attention of the large public. We also have an excellent vehicle in increasing the public understanding in the society of Finnish amateur astronomers Ursa. It is an organization for anyone interested in practically everything from visual phenomena in the air to the remote galaxies and the Big Bang. Ursa publishes a high-quality monthly magazine in Finnish and runs local amateur clubs. Last year its 80th birthday exhibition was one of the best-visited public events in Helsinki. It clearly gave a strong evidence of wide public interest in space in general and in space science in particular. Only curious people can grasp the beauty and importance of the underlying science. Thus, we should focus our public space science education and outreach primarily on waking up the curiosity of the public instead of providing ready answers from above.

THE DEARTH OF NEUTRAL HYDROGEN IN GALACTIC DWARF SPHEROIDAL GALAXIES

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

Spekkens, Kristine; Urbancic, Natasha; Mason, Brian S.

We present new upper limits on the neutral hydrogen (H I) content within the stellar half-light ellipses of 15 Galactic dwarf spheroidal galaxies (dSphs), derived from pointed observations with the Green Bank Telescope (GBT) as well as Arecibo L-band Fast ALFA survey and Galactic All-Sky Survey data. All of the limits M{sub H} {sub I}{sup lim} are more stringent than previously reported values, and those from the GBT improve upon constraints in the literature by a median factor of 23. Normalizing by V-band luminosity L{sub V} and dynamical mass M {sub dyn}, we find M{sub H} {sub I}{sup lim}/L{sub V}∼10{supmore » −3} M{sub ⊙}/L{sub ⊙} and M{sub H} {sub I}{sup lim}/M{sub dyn}∼5×10{sup −5}, irrespective of location in the Galactic halo. Comparing these relative H I contents to those of the Local Group and nearby neighbor dwarfs compiled by McConnachie, we find that the Galactic dSphs are extremely gas-poor. Our H I upper limits therefore provide the clearest picture yet of the environmental dependence of the H I content in Local Volume dwarfs. If ram pressure stripping explains the dearth of H I in these systems, then orbits in a relatively massive Milky Way are favored for the outer halo dSph Leo I, while Leo II and Canes Venatici I have had a pericentric passage in the past. For Draco and Ursa Minor, the interstellar medium mass that should accumulate through stellar mass loss in between pericentric passages exceeds M{sub H} {sub I}{sup lim} by a factor of ∼30. In Ursa Minor, this implies that either this material is not in the atomic phase, or that another mechanism clears the recycled gas on shorter timescales.« less

Naval Research Logistics Quarterly. Volume 28. Number 2,

DTIC Science & Technology

1981-06-01

Milwaukee Arnoldo Hax, Massachusetts Institute of Technology James G. Taylor, Naval Postgraduate School Alan J. Hoffman, IBM Corporation Harvey M. Wagner...geieral distributiiins /t). If /-I itself i,, if’ phase Itpe with representation (Pr .R f then f14) .1 = exp Ux )4r cxp IRA ) R (A it X ’rI exp l/t) c...23. n = 2 and m = I1, n = 4 in respective CPI times of 23.26 sec and 10.28 sec on IBM 360/65. Kuenne and Soland’s 191 largest reported problem was

Conference on Ordinary and Partial Differential Equations, 29 March to 2 April 1982.

DTIC Science & Technology

1982-04-02

Azztr. Boundary value problems for elliptic and parabolic equations in domains with corners The paper concerns initial - Dirichlet and initial - mixed...boundary value problems for parabolic equations. a ij(x,t)u x + ai(x,t)Ux. + a(x,t)u-u = f(x,t) i3 1 x Xl,...,Xn , n 2. We consider the case of...moment II Though it is well known, that the electron possesses an anomalous magnetic moment, this term has not been considered so far in the mathematical

Summer Study Program in Geophysical Fluid Dynamics - The Influence of Convection on Large-Scale Circulations - 1988

DTIC Science & Technology

1989-07-01

the vector of the body force." lo., ,P /’P l> 16 __ __ _ __ ___P . 19 U In the first lecture we define the buoyancy force, develop a simplified...force and l’is a unit vector along the motion vector . Integrating Bernoulli’s law over a closed loop one gets: I also [ C by integrating along the...convection. It is conveiient to write these equations as evolution equations for a atate vector U(x, z, t) where x is the horizontal coordinate vector

METHOD FOR PREPARING URANIUM MONOCARBIDE-PLUTONIUM MONOCARBIDE SOLID SOLUTION

DOEpatents

Ogard, A.E.; Leary, J.A.; Maraman, W.J.

1963-03-19

A method is given for preparing solid solutions of uranium monocarbide- plutonium monocarbide. In this method, the powder form of uranium dioxide, plutonium dioxide, and graphite are mixed in a ratio determined by the equation: xUO/sub 2/ + yPuO/sub 2/ + (2+z)C yields UxPu/sub y/C/sub z/ +2CO, where x + y equ al 1.0 and z is greater than 0.9 but less than 1.0. The resulting mixture is compacted and heated in a vacuum at a temperature of 1850 deg C. (AEC)

Wind erosion from a sagebrush steppe burned by wildfire: measurements of PM10 and total horizontal sediment flux

USGS Publications Warehouse

Wagenbrenner, Natalie S.; Germino, Matthew J.; Lamb, Brian K.; Robichaud, Peter R.; Foltz, Randy B.

2013-01-01

above the soil surface, had a maximum PM10 vertical flux of 100 mg m-2 s-1, and generated a large dust plume that was visible in satellite imagery. The peak PM10 concentration measured on-site at a height of 2 m in the downwind portion of the burned area was 690 mg m-3. Our results indicate that wildfire can convert a relatively stable landscape into one that is a major dust source.

Through the elliptical haze

NASA Image and Video Library

2015-11-30

Like a lighthouse in the fog the luminous core of NGC 2768 slowly fades outwards to a dull white haze in this image taken by the NASA/ESA Hubble Space Telescope. NGC 2768 is an elliptical galaxy in the constellation of Ursa Major (The Great Bear). It is a huge bundle of stars, dominated by a bright central region, where a supermassive black hole feasts on a constant stream of gas and dust being fed to it by its galactic host. The galaxy is also marked by a prominent plume of dust reaching out from the centre and lying perpendicular to the galaxy’s plane. This dust conceals a symmetrical, s-shaped pair of jets that are being produced by the supermassive black hole as it feeds.

Combined ultraviolet studies of astronomical source

NASA Technical Reports Server (NTRS)

Dupress, A. K.; Baliunas, S. L.; Blair, W. P.; Hartmann, L. W.; Huchra, J. P.; Raymond, J. C.; Smith, G. H.; Soderblom, D. R.

1985-01-01

As part of its Ultraviolet Studies of Astronomical Sources the Smithsonian Astrophysical Observatory for the period 1 Feb. 1985 to 31 July 1985 observed the following: the Cygnus Loop; oxygen-rich supernova remnants in 1E0102-72; the Large Magellanic Cloud supernova remnants; P Cygni profiles in dwarf novae; soft X-ray photoionization of interstellar gas; spectral variations in AM Her stars; the mass of Feige 24; atmospheric inhomogeneities in Lambda Andromedae and FF Aquarii; photometric and spectroscopic observation of Capella; Alpha Orionis; metal deficient giant stars; M 67 giants; high-velocity winds from giant stars; accretion disk parameters in cataclysmic variables; chromospheric emission of late-type dwarfs in visual binaries; chromospheres and transient regions of stars in the Ursa Major group; and low-metallicity blue galaxies.

Imaging the Disk and Jet of the Classical T Tauri Star AA Tau

NASA Astrophysics Data System (ADS)

Cox, Andrew; Grady, C.; Hammel, H. B.; Hornbeck, J.; Russell, R. W.; Sitko, M. L.; Woodgate, B. E.

2013-01-01

Previous studies of the classical T Tauri star AA Tau have interpreted the UX Orionis-like photo-polarimetric variability as being due to a warp in the inner disk caused by an inclined stellar magnetic dipole field. We test that these effects are macroscopically observable in the inclination and alignment of the disk. We use HST/STIS coronagraphic imagery to measure the V magnitude of the star for both STIS corona graphic observations, compare these data with optical photometry in the literature and find that unlike other classical T Tauri stars observed on the same HST program, the disk is most robustly detected at optical minimum light. We measure the outer disk radius, major axis position angle, and disk inclination, and find that the inner disk, as reported in the literature, is both mis-inclined and misaligned with respect to the outer disk. AA Tau drives a faint jet which is also misaligned with respect to the projection of the outer disk minor axis and which is poorly collimated near the star. The measured outer disk inclination, 71±1 degrees, is out of the inclination band suggested for stars with UX Orionis-like variability where no grain growth has occurred in the disk. The faintness of the disk, the small disk size, and visibility of the star and despite the high inclination, all indicate that the disk must have experienced grain growth and settling toward the disk midplane, which we verify by comparing the observed disk with model imagery from the literature.

Structure and thermodynamics of uranium-containing iron garnets

NASA Astrophysics Data System (ADS)

Guo, Xiaofeng; Navrotsky, Alexandra; Kukkadapu, Ravi K.; Engelhard, Mark H.; Lanzirotti, Antonio; Newville, Matthew; Ilton, Eugene S.; Sutton, Stephen R.; Xu, Hongwu

2016-09-01

Use of crystalline garnet as a waste form phase appears to be advantageous for accommodating actinides from nuclear waste. Previous studies show that large amounts of uranium (U) and its analogues such as cerium (Ce) and thorium (Th) can be incorporated into the garnet structure. In this study, we synthesized U loaded garnet phases, Ca3UxZr2-xFe3O12 (x = 0.5-0.7), along with the endmember phase, Ca3(Zr2)SiFe3+2O12, for comparison. The oxidation states of U were determined by X-ray photoelectron and absorption spectroscopies, revealing the presence of mixed pentavalent and hexavalent uranium in the phases with x = 0.6 and 0.7. The oxidation states and coordination environments of Fe were measured using transmission 57Fe-Mössbauer spectroscopy, which shows that all iron is tetrahedrally coordinated Fe3+. U substitution had a significant effect on local environments, the extent of U substitution within this range had a minimal effect on the structure, and unlike in the x = 0 sample, Fe exists in two different environments in the substituted garnets. The enthalpies of formation of garnet phases from constituent oxides and elements were first time determined by high temperature oxide melt solution calorimetry. The results indicate that these substituted garnets are thermodynamically stable under reducing conditions. Our structural and thermodynamic analysis further provides explanation for the formation of natural uranium garnet, elbrusite-(Zr), and supports the potential use of Ca3UxZr2-xFe3O12 as viable waste form phases for U and other actinides.

The Recognition of Words from Phonemes in Continuous Speech.

DTIC Science & Technology

1981-12-01

C A BAKER UNCLASSIFIED AFIT/GE/EE/810ŝ NL EEEEEEIIEEEEI EEEEEEEEEEEEEE EEEEIIEEEIIEI IIIEEEEIIEIIEE EIEEEEEEEEIIEE IIIEIIEEEEEEEE r- ~. 7 c ~ F IVV...82 06 16 011 AFIT/GE/EE/ 81 D -9 THE RECOGNITION OF WORDS FROM PHONEMES IN CONTINUOUS SPEECH THESIS AFIT/GE/EE/81D-9 Claude A. Baker Captain USAF...33. OU Qbey 14. ZX zoo 34. UX foot 15. SH 5h e 35. UU b.Qt 16. ZH azure 36. UH up 17. MX me 37. UH about 18. NX no 38. ER woQrd 19. NG sinkg 39. XX NA

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.

Anomalous Eclipses of the Young Star RW Aur A

NASA Astrophysics Data System (ADS)

Lamzin, S.; Cheryasov, D.; Chuntonov, G.; Dodin, A.; Grankin, K.; Malanchev, K.; Nadzhip, A.; Safonov, B.; Shakhovskoy, D.; Shenavrin, V.; Tatarnikov, A.; Vozyakova, O.

2017-06-01

Results of UBVRIJHKLM photometry, VRI polarimetry and optical spectroscopy of a young star RW Aur A obtained during 2010-11 and 2014-16 dimming events are presented. During the second dimming the star decreased its brightness to ΔV >4.5 mag, polarization of its light in I-band was up to 30 %, and color-magnitude diagramm was similar to that of UX Ori type stars. We conclude that the reason of both dimmings is an eclipses of the star by dust screen, but the size of the screen is much larger than in the case of UXORs.

Analysis of Advanced CI Applications

DTIC Science & Technology

1981-03-01

rner Street Boston, ,/iA 021 10 Atcn« L,r. Fred Quelle AF^L/Of (ianscum AHB, MA 01/31 Atun « ./r. John Oanny AF..L/AL0 Kirtiand AHB...M d/11 / Atun « .jr. J. d. Hoyye ArJC/OL Andrew^ Ar’d, DO 20.334 Atv,n« oapt Oyole AFdC/X^rU Andrews Af-d, ÜO 20334 8 10 II...8217’■ ..:., ■■ . >. ■ — Ini Mil/Li;icoin Lab H. ). üux l-i Le ; in ji-on, MA U^l /.j Atun » iJr. ü. üreenwooj 4U Naval

Elastodynamic Impact into Piezoelectric Media

DTIC Science & Technology

2014-09-01

NUMBER 5b. GRANT NUMBER 4. TITLE AND SUBTITLE 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5e. TASK NUMBER 6. AUTHOR(S) 5f. WORK UNIT NUMBER...m2, and h = e/ǫ. In addition, from Newton’s second law, ρ ∂2u(x, t) ∂t2 = ∂σ(x, t) ∂x , for t > 0, x ∈ (−∞,∞) , (4) where ρ is the mass density in kg...the second is given by the boundary condition between the target and the half-space derived elsewhere,11 σ1(l, t) = zhv1(l, t) , (23) and the third

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

Drryl P. Butt; Brian Jaques

Research conducted for this NERI project has advanced the understanding and feasibility of nitride nuclear fuel processing. In order to perform this research, necessary laboratory infrastructure was developed; including basic facilities and experimental equipment. Notable accomplishments from this project include: the synthesis of uranium, dysprosium, and cerium nitrides using a novel, low-cost mechanical method at room temperature; the synthesis of phase pure UN, DyN, and CeN using thermal methods; and the sintering of UN and (Ux, Dy1-x)N (0.7 ≤ X ≤ 1) pellets from phase pure powder that was synthesized in the Advanced Materials Laboratory at Boise State University.

International Conference on Control and Estimation of Distributed Parameter Systems: Nonlinear Phenomena Held in Vorau, Austria on July 18-24, 1993

DTIC Science & Technology

1993-07-24

detection anit charact(erization in smart material structures 21 NI. BER;OUNIoUX, T. N’IANNIKK6) AN) D. TmIA: Optimnality conditions for non-qumalified...UISA DAMAGE DETECTION AND CHARACTERIZATION IN SMART MATERIAL STRUCTURES HI. TF. BANKS AND) Y, WAN(, C~enter for Rtsvarchliti Scientific Cumpiptatioii...111,u’, + +pt,’, ,x 123 22 (3.3) 0~’ ={( othi’i-wist’. Wie iitmt sought to dlemnonstrat~e tiht capabliity of1 pieoll"t~tItrit m~aterialds inl smart

Research into Traveling Wave Control in Flexible Structures

DTIC Science & Technology

1990-06-15

Displacement is the measured variable in all of the rod examples. Y = F I s i n(k + k 0) _______________ ikEA 21- k [ (24)- -- .r k k 0 F - Choosing m = 4 in...the value of Eq. (25) function of position is given by becomes U2 for that mode. U(X)= F 4 ( 2 e + e (21) Figure 3 shows the magnitudes of the ikEA ...for providing a reasonable length sensor. ___ sin(k_ The dash-dot curve in Fig. 4 shows the ikEA 1- _ 2 1- e-as (28) magnitude and phase of a

Chemistry in the final stages of stellar evolution: Millimeter and submillimeter observations of supergiants and planetary nebulae

NASA Astrophysics Data System (ADS)

Edwards, Jessica Louise

High mass loss rates in evolved stars make them the major contributors to recycling processed material back into the interstellar medium. This mass loss creates large circumstellar shells, rich in molecular material. This dissertation presents millimeter and submillimeter studies of the end stages of low mass and high mass stars in order to probe their molecular content in more detail. In low mass stars, the molecular material is carried on into the planetary nebula (PN) stage. Observations of CS, HCO+, and CO in planetary nebulae (PNe) of various post-asymptotic giant branch ages have shown that molecular abundances in these objects do not significantly vary with age, as previously thought. More detailed observations of the slightly oxygen-rich PN NGC 6537 resulted in the detection of CN, HCN, HNC, CCH, CS, SO, H 2CO, HCO+ and N2H+, as well as numerous 13C isotopologues. Observations of the middle-aged PN M2-48 showed the presence of CN, HCN, HNC, CS, SO, SO2, SiO, HCO+, N2H+, and several 13C isotopologues. These observations represent the first detections of CS, SO, SO2, and SiO in any planetary nebula. The implications of these observations are discussed. A 1 mm spectral survey of the supergiant star NML Cygni has been carried out with the Arizona Radio Observatory Submillimeter Telescope resulting in the observation of 102 emission features arising from 17 different molecules and 4 unidentified features. The line profiles observed in this circumstellar shell are asymmetric and vary between different molecules, akin to what has been seen in another supergiant, VY Canis Majoris. The non-LTE radiative transfer code ESCAPADE has been used to model molecular abundances in the various asymmetric outflows of VY Canis Majoris, showing just how chemically and kinematically complex these supergiant circumstellar envelopes really are.

Detection of a Hot Subdwarf Companion to the Be Star FY Canis Majoris

NASA Astrophysics Data System (ADS)

Peters, Geraldine J.; Gies, Douglas R.; Grundstrom, Erika D.; McSwain, M. Virginia

2008-10-01

The rapid rotation of Be stars may be caused in some cases by past mass and angular momentum accretion in an interacting binary in which the mass donor is currently viewed as a small, hot subdwarf stripped of its outer envelope. Here we report on the spectroscopic detection of such a subdwarf in the Be binary system FY Canis Majoris from the analysis of data acquired by the IUE spacecraft and KPNO Coudé Feed Telescope over the course of 16 and 21 yr, respectively. We present a double-lined spectroscopic orbit for the binary based on radial velocities from the IUE spectra and use the orbital solutions with a Doppler tomography algorithm to reconstruct the components' UV spectra. The subdwarf is hot (Teff = 45 +/- 5 kK) and has a mass of about 1.3 M⊙ and a radius of about 0.6 R⊙. It contributes about 4% as much flux as the Be star does in the FUV. We also present observations of the Hα and He I λ6678 emission features that are formed in the circumstellar disk of the Be star. Orbital flux and velocity variations in the He I λ6678 profile indicate that much of the emission forms along the disk rim facing the hot subdwarf where the disk is probably heated by the incident radiation from the subdwarf. A study of the FUV infall shell lines discovered in the 1980s confirms their episodic presence but reveals that they tend to be found around both quadrature phases, unlike the pattern in Algol binaries. Phase-dependent variations in the UV N V doublet suggest the presence of a N-enhanced wind from the subdwarf and a possible shock-interaction region between the stars where the subdwarf's wind collides with the disk of the Be star.

Direct imaging and new technologies to search for substellar companions around MGs cool dwarfs

NASA Astrophysics Data System (ADS)

Gálvez-Ortiz, M. C.; Clarke, J. R. A.; Pinfield, D. J.; Folkes, S. L.; Jenkins, J. S.; García Pérez, A. E.; Burningham, B.; Day-Jones, A. C.; Jones, H. R. A.

2011-07-01

We describe here our project based in a search for sub-stellar companions (brown dwarfs and exo-planets) around young ultra-cool dwarfs (UCDs) and characterise their properties. We will use current and future technology (high contrast imaging, high-precision Doppler determinations) from the ground and space (VLT, ELT and JWST), to find companions to young objects. Members of young moving groups (MGs) have clear advantages in this field. We compiled a catalogue of young UCD objects and studied their membership to five known young moving groups: Local Association (Pleiades moving group, 20-150 Myr), Ursa Mayor group (Sirius supercluster, 300 Myr), Hyades supercluster (600 Myr), IC 2391 supercluster (35 Myr) and Castor moving group (200 Myr). To assess them as members we used different kinematic and spectroscopic criteria.

Laboratory investigation of coupled deformation and fluid flow in mudrock: implications for slope stability in the Ursa Basin, Gulf of Mexico

NASA Astrophysics Data System (ADS)

Flemings, P. B.; Song, I.; Saffer, D. M.

2012-04-01

Integrated Ocean Drilling Program (IODP) Expedition 308 was dedicated to the study of fluid flow, overpressure, and slope stability in the Ursa Basin, on the continental slope of the Gulf of Mexico. In this location, turbidite channel levees deposited a wedge-shaped body: the deposition rate in the thick part of the wedge exceeded 12 mm/yr. This rapid deposition of fine grained sediments generated excess pore pressure observed near the seafloor. IODP drilling focused on three Sites: U1322, U1323, and U1324, along the steepest slope (2°) on the eastern section of the Ursa Canyon levee deposits. In this study, we conducted a suite of deformation experiments on samples from Site 1324, to understand the stress-strain behavior and stress history of the recovered core material. Our samples were taken from depths of 30-160 meters below seafloor, and are composed of ~40% silt and ~60% clay, with porosities ranging from ~42-55%. We first conducted uniaxial consolidation tests to determine pre-consolidation stresses and define deformation behavior due to simulated vertical loading. In a subset of tests, we subjected the samples to undrained shearing following consolidation, to define the friction angle and define relationships between stress state and deformation. We find that the lateral effective stress during uniaxial compression is 56-64% of the vertical effective stress (avg. K0=0.6). Pre-consolidation stresses suggest that pore pressure is hydrostatic to 50 mbsf (meters below seafloor), and is overpressured below this, with excess pressures up to 70% of the hydrostatic effective vertical stress (λ*=0.7) at 160 mbsf. The time coefficient of consolidation (cv) in these experiments is ~2.2x10-8 m2/s. Undrained shear tests define a failure envelope with a residual friction angle (φ) of 23° and zero cohesion. In our shearing tests, we observed no pore pressure change during initial (primarily elastic) shear deformation, but note a monotonic increase in pore pressure during the later plastic shear deformation, possibly due to re-organization of sediment grains. Our consolidated undrained tests suggest that the slope in the study area should remain stable during sedimentation, despite the high overpressure (λ*=0.7). However, this stress condition could be affected by gravitational and seepage forces that cause horizontal extension along the slope. In this case, a reduction in horizontal confining stress would render the slope sediments unstable (drive them to active failure) as defined by the Coulomb criterion. If shear strain during slope failure leads to plastic deformation of the sediments, this would also induce a pore pressure increase, further decreasing the factor of safety (FS) for landslides. For the landslides of the slope (i.e., FS=1.0), the overpressure rate λ* should reach 0.92 for the given slope (2°). However, active normal faulting takes place at lower values of λ* (0.2-0.8). Our analysis suggests that the instability of the slope may arise more likely from normal faults dipping stiff (45°+φ/2) than from landslides slipping on a plane parallel to such a gentle slope of seafloor.

Same-Day Identification and Antimicrobial Susceptibility Testing of Bacteria in Positive Blood Culture Broths Using Short-Term Incubation on Solid Medium with the MicroFlex LT, Vitek-MS, and Vitek2 Systems

PubMed Central

Ha, Jihye; Han, Geum Hee; Kim, Myungsook; Lee, Kyungwon

2018-01-01

Background Early and appropriate antibiotic treatment improves the clinical outcome of patients with septicemia; therefore, reducing the turn-around time for identification (ID) and antimicrobial susceptibility test (AST) results is essential. We established a method for rapid ID and AST using short-term incubation of positive blood culture broth samples on solid media, and evaluated its performance relative to that of the conventional method using two rapid ID systems and a rapid AST method. Methods A total of 254 mono-microbial samples were included. Positive blood culture samples were incubated on blood agar plates for six hours and identified by the MicroFlex LT (Bruker Daltonics) and Vitek-MS (bioMeriéux) systems, followed by AST using the Vitek2 System (bioMeriéux). Results The correct species-level ID rates were 82.3% (209/254) and 78.3% (199/254) for the MicroFlex LT and Vitek-MS platforms, respectively. For the 1,174 microorganism/antimicrobial agent combinations tested, the rapid AST method showed total concordance of 97.8% (1,148/1,174) with the conventional method, with a very major error rate of 0.5%, major error rate of 0.7%, and minor error rate of 1.0%. Conclusions Routine implementation of this short-term incubation method could provide ID results on the day of blood culture-positivity detection and one day earlier than the conventional AST method. This simple method will be very useful for rapid ID and AST of bacteria from positive blood culture bottles in routine clinical practice. PMID:29401558

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).

NICER and MAXI Observations of Two Large X-ray Flares from RS CVn Binaries

NASA Astrophysics Data System (ADS)

Drake, Stephen A.; Hamaguchi, Kenji; Corcoran, Michael Francis; Iwakiri, Wataru; Sasaki, Ryo; Kawai, Hiroki; Tsuboi, Yohko; Enoto, Teruaki; NICER Science Team

2018-01-01

NICER has observed two giant X-ray flares on the active binary systems, GT Mus and UX Ari, in response to their detections by the MAXI all-sky X-ray monitor onboard the ISS, with a delay of about a day in each case. The large effective area of the NICER X-ray optics means that high signal-to-noise spectra with more than 200,000 counts were obtained in relatively short exposures totaling less than an hour in each set of observations.MAXI detected a transient of 5.5 x 10^-10 erg/s/cm2 at the position of the active RS CVn binary GT Mus (G5/8 III + ?) early on 2017 July 19. NICER started its observations about 1 day later, and intermittently monitored the decay for the next 2.5 days, accumulating about 1,600 seconds exposure. The NICER light curve shows a smooth, gradual flux decline by a factor of two for the first 2 days, followed by an apparent flattening in the last half day. The dominant plasma temperature remained at ~40 million K during this period, suggesting an ongoing continuous heating during the decay phase.NICER also followed up another MAXI-detected flare in October 2017, this one from the nearby active system, UX Ari. NICER's X-ray spectrum shows clear neon and oxygen lines, while the emissionfrom iron ions is not as prominent as it is in most flares, implying an abundance of only ~10% solar which is significantly lower than previous inferred coronal Fe abundances for this star, although this result is dependent on the NICER gain correction.

Imaging the Disk and Jet of the Classical T Tauri Star AA Tau

NASA Technical Reports Server (NTRS)

Cox, Andrew W.; Grady, Carol A.; Hammel, Heidi B.; Hornbeck, Jeremy; Russell, Ray W.; Sitko, Michael L.; Woodgate, Bruce E.

2013-01-01

Previous studies of the classical T Tauri star AA Tau have interpreted the UX-Orionis-like photo-polarimetric variability as being due to a warp in the inner disk caused by an inclined stellar magnetic dipole field. We test that these effects are macroscopically observable in the inclination and alignment of the disk. We use Hubble Space Telescope (HST)/STIS coronagraphic imagery to measure the V magnitude of the star for both STIS coronagraphic observations, compare these data with optical photometry in the literature, and find that, unlike other classical T Tauri stars observed in the same HST program, the disk is most robustly detected in scattered light at stellar optical minimum light.We measure the outer disk radius, 1 inch.15 plus-minus 0 inch.10, major-axis position angle, and disk inclination and find that the inner disk, as reported in the literature, is both misinclined and misaligned with respect to the outer disk. AA Tau drives a faint jet, detected in both STIS observations and in follow-on Goddard Fabry-Perot imagery, which is also misaligned with respect to the projection of the outer disk minor axis and is poorly collimated near the star, but which can be traced 21 inches from the star in data from 2005. The measured outer disk inclination, 71deg plus-minus 1deg, is out of the range of inclinations suggested for stars with UX-Orionis-like variability when no grain growth has occurred in the disk. The faintness of the disk, small disk size, and detection of the star despite the high inclination all indicate that the dust disk must have experienced grain growth and settling toward the disk midplane, which we verify by comparing the observed disk with model imagery from the literature.

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

Pott, Jorg-Uwe; Perrin, Marshall D.; Furlan, Elise

With the Keck Interferometer, we have studied at 2 {mu}m the innermost regions of several nearby, young, dust-depleted 'transitional' disks. Our observations target five of the six clearest cases of transitional disks in the Taurus/Auriga star-forming region (DM Tau, GM Aur, LkCa 15, UX Tau A, and RY Tau) to explore the possibility that the depletion of optically thick dust from the inner disks is caused by stellar companions rather than the more typical planet-formation hypothesis. At the 99.7% confidence level, the observed visibilities exclude binaries with flux ratios of at least 0.05 and separations ranging from 2.5 to 30more » mas (0.35-4 AU) over {approx}>94% of the area covered by our measurements. All targets but DM Tau show near-infrared (NIR) excess in their spectral energy distribution (SED) higher than our companion flux ratio detection limits. While a companion has previously been detected in the candidate transitional disk system CoKu Tau/4, we can exclude similar mass companions as the typical origin for the clearing of inner dust in transitional disks and of the NIR excess emission. Unlike CoKu Tau/4, all our targets show some evidence of accretion. We find that all but one of the targets are clearly spatially resolved, and UX Tau A is marginally resolved. Our data are consistent with hot material on small scales (0.1 AU) inside of and separated from the cooler outer disk, consistent with the recent SED modeling. These observations support the notion that some transitional disks have radial gaps in their optically thick material, which could be an indication for planet formation in the habitable zone ({approx} a few AU) of a protoplanetary disk.« less

IMAGING THE DISK AND JET OF THE CLASSICAL T TAURI STAR AA TAU

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

Cox, Andrew W.; Grady, Carol A.; Hammel, Heidi B.

2013-01-01

Previous studies of the classical T Tauri star AA Tau have interpreted the UX-Orionis-like photo-polarimetric variability as being due to a warp in the inner disk caused by an inclined stellar magnetic dipole field. We test that these effects are macroscopically observable in the inclination and alignment of the disk. We use Hubble Space Telescope (HST)/STIS coronagraphic imagery to measure the V magnitude of the star for both STIS coronagraphic observations, compare these data with optical photometry in the literature, and find that, unlike other classical T Tauri stars observed in the same HST program, the disk is most robustlymore » detected in scattered light at stellar optical minimum light. We measure the outer disk radius, 1.''15 {+-} 0.''10, major-axis position angle, and disk inclination and find that the inner disk, as reported in the literature, is both misinclined and misaligned with respect to the outer disk. AA Tau drives a faint jet, detected in both STIS observations and in follow-on Goddard Fabry-Perot imagery, which is also misaligned with respect to the projection of the outer disk minor axis and is poorly collimated near the star, but which can be traced 21'' from the star in data from 2005. The measured outer disk inclination, 71 Degree-Sign {+-} 1 Degree-Sign , is out of the range of inclinations suggested for stars with UX-Orionis-like variability when no grain growth has occurred in the disk. The faintness of the disk, small disk size, and detection of the star despite the high inclination all indicate that the dust disk must have experienced grain growth and settling toward the disk midplane, which we verify by comparing the observed disk with model imagery from the literature.« less

Same-Day Identification and Antimicrobial Susceptibility Testing of Bacteria in Positive Blood Culture Broths Using Short-Term Incubation on Solid Medium with the MicroFlex LT, Vitek-MS, and Vitek2 Systems.

PubMed

Ha, Jihye; Hong, Sung Kuk; Han, Geum Hee; Kim, Myungsook; Yong, Dongeun; Lee, Kyungwon

2018-05-01

Early and appropriate antibiotic treatment improves the clinical outcome of patients with septicemia; therefore, reducing the turn-around time for identification (ID) and antimicrobial susceptibility test (AST) results is essential. We established a method for rapid ID and AST using short-term incubation of positive blood culture broth samples on solid media, and evaluated its performance relative to that of the conventional method using two rapid ID systems and a rapid AST method. A total of 254 mono-microbial samples were included. Positive blood culture samples were incubated on blood agar plates for six hours and identified by the MicroFlex LT (Bruker Daltonics) and Vitek-MS (bioMeriéux) systems, followed by AST using the Vitek2 System (bioMeriéux). The correct species-level ID rates were 82.3% (209/254) and 78.3% (199/254) for the MicroFlex LT and Vitek-MS platforms, respectively. For the 1,174 microorganism/antimicrobial agent combinations tested, the rapid AST method showed total concordance of 97.8% (1,148/1,174) with the conventional method, with a very major error rate of 0.5%, major error rate of 0.7%, and minor error rate of 1.0%. Routine implementation of this short-term incubation method could provide ID results on the day of blood culture-positivity detection and one day earlier than the conventional AST method. This simple method will be very useful for rapid ID and AST of bacteria from positive blood culture bottles in routine clinical practice. © The Korean Society for Laboratory Medicine

Orbital Elements and Stellar Parameters of the Active Binary UX Arietis

NASA Astrophysics Data System (ADS)

Hummel, C. A.; Monnier, J. D.; Roettenbacher, R. M.; Torres, G.; Henry, G. W.; Korhonen, H.; Beasley, A.; Schaefer, G. H.; Turner, N. H.; Ten Brummelaar, T.; Farrington, C. D.; Sturmann, J.; Sturmann, L.; Baron, F.; Kraus, S.

2017-08-01

Stellar activity observed as large surface spots, radio flares, or emission lines is often found in binary systems. UX Arietis exhibits these signs of activity, originating on the K0 subgiant primary component. Our aim is to resolve the binary, measure the orbital motion, and provide accurate stellar parameters such as masses and luminosities to aid in the interpretation of the observed phenomena. Using the CHARA six-telescope optical long-baseline array on Mount Wilson, California, we obtained amplitudes and phases of the interferometric visibility on baselines up to 330 m in length, resolving the two components of the binary. We reanalyzed archival Center for Astrophysics spectra to disentangle the binary component spectra and the spectrum of the third component, which was resolved by speckle interferometry. We also obtained new spectra with the Nordic Optical Telescope, and we present new photometric data that we use to model stellar surface spot locations. Both interferometric visibilities and spectroscopic radial velocities are modeled with a spotted primary stellar surface using the Wilson-Devinney code. We fit the orbital elements to the apparent orbit and radial velocity data to derive the distance (52.1 ± 0.8 pc) and stellar masses ({M}{{P}}=1.30+/- 0.06 {M}⊙ , {M}{{S}}=1.14+/- 0.06 {M}⊙ ). The radius of the primary can be determined to be {R}{{P}}=5.6+/- 0.1 {R}⊙ and that of the secondary to be {R}{{S}}=1.6+/- 0.2 {R}⊙ . The equivalent spot coverage of the primary component was found to be 62% with an effective temperature 20% below that of the unspotted surface.

Comparison of risk of malignancy indices; RMI 1-4 in borderline ovarian tumor.

PubMed

Yenen, M C; Alanbay, I; Aktürk, E; Ercan, C M; Coksuer, H; Karaşahin, E; Ozan, H; Dede, M

2012-01-01

The aim of this study was to evaluate prognostic values of the risk of malignancy index (RMI)/1-4 in patients with borderline ovarian tumors (BOTs). The study consisted of 50 patients with BOT diagnosed and treated between 2005-2010 and 50 patients with benign adnexal massses between 2009-2010 as a control comparison group in the retropsective study. Preoperative serum CA125, U score, tumor size (S), and menopausal status were recorded. The RMI 1-3 was calculated according to the formula; UxMxCA125 and RMI4 formulation was; UxMxCA125xS. S equaled 1 for tumor size <7 cm and was 2 when size a 7 cm. The RMI 1-4 indices were calculated for all patients together with the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy (DA). The performances of RMI indices were evaluated by McNemar's test and determined the best score cutoff value by the receiver operating characteristic (ROC) curve. The mean age, median value of CA125, ultrasound score, menopausal status, median values of RMI 1-4 of BOTs were statistically higher than benign adnexal masses. The sensitivity of RMI 1-4 was 26, 36, 62, and 60% at cutoff 200 level, respectively. The areas under curve of RMI 1-4 were found to be 0.676, 0.665, 0.668 and 0.734, respectively. DA of RMI 1-4 was found to be 56, 59, 50, and 71, respectively. When RMI 1-4 indices were compared with each other RMI 4 was the best RMI for BOTs. RMI 4 was the best predictive RMI for preoperative discrimination of BOT at a cutoff level of 200.

Characteristic Lifetime Of A Polarized Feature In The V=0, J=1-0 Sio Maser VY Canis Majoris

NASA Astrophysics Data System (ADS)

Rislow, Benjamin; McIntosh, G. C.

2008-05-01

A time series cross correlation analysis has been developed for calculating the characteristic lifetime of linearly polarized features in the spectrum of silicon monoxide masers. Our observations of VY CMa in the v=0, J=1→0; transition from June 2003 to March 2006 revealed a highly linearly polarized feature at Vlsr=18.5 km s-1. Applying the cross correlation to this feature gave a characteristic lifetime of 2800 days. This time is much longer than the v=1, J=2→1; transition's lifetime of 645 days and indicates that the two transitions occur under different physical conditions. This research was supported by the University of Minnesota and the University of Minnesota, Morris.

Dark matter searches with Cherenkov telescopes: nearby dwarf galaxies or local galaxy clusters?

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

Sánchez-Conde, Miguel A.; Cannoni, Mirco; Gómez, Mario E.

2011-12-01

In this paper, we compare dwarf galaxies and galaxy clusters in order to elucidate which object class is the best target for gamma-ray DM searches with imaging atmospheric Cherenkov telescopes (IACTs). We have built a mixed dwarfs+clusters sample containing some of the most promising nearby dwarf galaxies (Draco, Ursa Minor, Wilman 1 and Segue 1) and local galaxy clusters (Perseus, Coma, Ophiuchus, Virgo, Fornax, NGC 5813 and NGC 5846), and then compute their DM annihilation flux profiles by making use of the latest modeling of their DM density profiles. We also include in our calculations the effect of DM substructure.more » Willman 1 appears as the best candidate in the sample. However, its mass modeling is still rather uncertain, so probably other candidates with less uncertainties and quite similar fluxes, namely Ursa Minor and Segue 1, might be better options. As for galaxy clusters, Virgo represents the one with the highest flux. However, its large spatial extension can be a serious handicap for IACT observations and posterior data analysis. Yet, other local galaxy cluster candidates with more moderate emission regions, such as Perseus, may represent good alternatives. After comparing dwarfs and clusters, we found that the former exhibit annihilation flux profiles that, at the center, are roughly one order of magnitude higher than those of clusters, although galaxy clusters can yield similar, or even higher, integrated fluxes for the whole object once substructure is taken into account. Even when any of these objects are strictly point-like according to the properties of their annihilation signals, we conclude that dwarf galaxies are best suited for observational strategies based on the search of point-like sources, while galaxy clusters represent best targets for analyses that can deal with rather extended emissions. Finally, we study the detection prospects for present and future IACTs in the framework of the constrained minimal supersymmetric standard model. We find that the level of the annihilation flux from these targets is below the sensitivities of current IACTs and the future CTA.« less

Dark Matter Searches with Cherenkov Telescopes: Nearby Dwarf Galaxies or Local Galaxy Clusters?

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

Sanchez-Conde, Miguel A.; /KIPAC, Menlo Park /SLAC /IAC, La Laguna /Laguna U., Tenerife; Cannoni, Mirco

2012-06-06

In this paper, we compare dwarf galaxies and galaxy clusters in order to elucidate which object class is the best target for gamma-ray DM searches with imaging atmospheric Cherenkov telescopes (IACTs). We have built a mixed dwarfs+clusters sample containing some of the most promising nearby dwarf galaxies (Draco, Ursa Minor, Wilman 1 and Segue 1) and local galaxy clusters (Perseus, Coma, Ophiuchus, Virgo, Fornax, NGC 5813 and NGC 5846), and then compute their DM annihilation flux profiles by making use of the latest modeling of their DM density profiles. We also include in our calculations the effect of DM substructure.more » Willman 1 appears as the best candidate in the sample. However, its mass modeling is still rather uncertain, so probably other candidates with less uncertainties and quite similar fluxes, namely Ursa Minor and Segue 1, might be better options. As for galaxy clusters, Virgo represents the one with the highest flux. However, its large spatial extension can be a serious handicap for IACT observations and posterior data analysis. Yet, other local galaxy cluster candidates with more moderate emission regions, such as Perseus, may represent good alternatives. After comparing dwarfs and clusters, we found that the former exhibit annihilation flux profiles that, at the center, are roughly one order of magnitude higher than those of clusters, although galaxy clusters can yield similar, or even higher, integrated fluxes for the whole object once substructure is taken into account. Even when any of these objects are strictly point-like according to the properties of their annihilation signals, we conclude that dwarf galaxies are best suited for observational strategies based on the search of point-like sources, while galaxy clusters represent best targets for analyses that can deal with rather extended emissions. Finally, we study the detection prospects for present and future IACTs in the framework of the constrained minimal supersymmetric standard model. We find that the level of the annihilation flux from these targets is below the sensitivities of current IACTs and the future CTA.« less

Dark matter searches with Cherenkov telescopes: nearby dwarf galaxies or local galaxy clusters?

NASA Astrophysics Data System (ADS)

Sánchez-Conde, Miguel A.; Cannoni, Mirco; Zandanel, Fabio; Gómez, Mario E.; Prada, Francisco

2011-12-01

In this paper, we compare dwarf galaxies and galaxy clusters in order to elucidate which object class is the best target for gamma-ray DM searches with imaging atmospheric Cherenkov telescopes (IACTs). We have built a mixed dwarfs+clusters sample containing some of the most promising nearby dwarf galaxies (Draco, Ursa Minor, Wilman 1 and Segue 1) and local galaxy clusters (Perseus, Coma, Ophiuchus, Virgo, Fornax, NGC 5813 and NGC 5846), and then compute their DM annihilation flux profiles by making use of the latest modeling of their DM density profiles. We also include in our calculations the effect of DM substructure. Willman 1 appears as the best candidate in the sample. However, its mass modeling is still rather uncertain, so probably other candidates with less uncertainties and quite similar fluxes, namely Ursa Minor and Segue 1, might be better options. As for galaxy clusters, Virgo represents the one with the highest flux. However, its large spatial extension can be a serious handicap for IACT observations and posterior data analysis. Yet, other local galaxy cluster candidates with more moderate emission regions, such as Perseus, may represent good alternatives. After comparing dwarfs and clusters, we found that the former exhibit annihilation flux profiles that, at the center, are roughly one order of magnitude higher than those of clusters, although galaxy clusters can yield similar, or even higher, integrated fluxes for the whole object once substructure is taken into account. Even when any of these objects are strictly point-like according to the properties of their annihilation signals, we conclude that dwarf galaxies are best suited for observational strategies based on the search of point-like sources, while galaxy clusters represent best targets for analyses that can deal with rather extended emissions. Finally, we study the detection prospects for present and future IACTs in the framework of the constrained minimal supersymmetric standard model. We find that the level of the annihilation flux from these targets is below the sensitivities of current IACTs and the future CTA.

Ada Compiler Validation Summary Report. Certificate Number: 910721I1. 11194, Telesoft TeleGen2 (Trademark) Ada Host Development System, Version 4.1, for MacII Systems MacIIfx under A/UX 2.0 Host and Target.

DTIC Science & Technology

1991-07-18

controls Lhe execution of programs and that System provides services such as resource allocation, scheduling, input/output control, and data management...greater than 5330 making the cnecking of :his :ctet-;e 17pra:n2zal. 2-3 _MPLMENTAT: ZN DEPENDENC ::S 2.3 TEST MCDIFICAT:CNS Modificat-ons (see section...implementation. it also indicates te default options. The options invoked explicitly for validation testing are ven on the next page, wnich was supplied by the

Finite Difference Calculation of an Inviscid Transonic Flow over Oscillating Airfoils,

DTIC Science & Technology

1980-10-01

8217 processing results based on: W , withn c’rapns, etc, were preparec. 1Ihese programs wer,< wr it tvfl iP. theO odk ! for a FACOM2 _075 :cmptr wit- array...and numbers of mesh images used in the calculation in each are shown collectively in Table I. The numbers of the figures showing the results of the...pressure .. ... a 6 distributions - odk - A. -0.0 0. 1.0 EXERIMfNT iM O. 745 ____P_____%d ____ I TIJOEM0I1 OZ-8*KA7M OT "NSITI0N STRIP &6=0.5" AN II"UX

Validation Summary Report: TLD Systems, Ltd., TLD HP 9000/MIL-STD-1750A Ada Compiler System, Ver 2.9.0, HP-UX Ver 7.0 (Host) to running TLDmps (Target), 920319W1.11243

DTIC Science & Technology

1992-04-30

9G.dgal. Wath ~nglon. DC 20503l 1. AGENCY USE (Leave 2. REPORT j3. REPORT TYPE AND DATES I Final: 30 April 92 4. TITLE AND 5.FUNDING Validation Summary...2-4 CHAPTER 3 PROCESSING INFORMATION 3.1 TESTING EVIRaONMflr.. ............ ............ 3-1 3.2 SUM’MARYYOOTE TRESUT ESU.L...ACVC an Ada implementation must process each test of the customized test suite according to the Ada Standard. 1.4 DEFINITION OF TERMS Ada Compiler

Local-in-space blow-up criteria for a class of nonlinear dispersive wave equations

NASA Astrophysics Data System (ADS)

Novruzov, Emil

2017-11-01

This paper is concerned with blow-up phenomena for the nonlinear dispersive wave equation on the real line, ut -uxxt +[ f (u) ] x -[ f (u) ] xxx +[ g (u) + f″/(u) 2 ux2 ] x = 0 that includes the Camassa-Holm equation as well as the hyperelastic-rod wave equation (f (u) = ku2 / 2 and g (u) = (3 - k) u2 / 2) as special cases. We establish some a local-in-space blow-up criterion (i.e., a criterion involving only the properties of the data u0 in a neighborhood of a single point) simplifying and precising earlier blow-up criteria for this equation.

Analytical Approach to (2+1)-Dimensional Boussinesq Equation and (3+1)-Dimensional Kadomtsev-Petviashvili Equation

NASA Astrophysics Data System (ADS)

Sarıaydın, Selin; Yıldırım, Ahmet

2010-05-01

In this paper, we studied the solitary wave solutions of the (2+1)-dimensional Boussinesq equation utt -uxx-uyy-(u2)xx-uxxxx = 0 and the (3+1)-dimensional Kadomtsev-Petviashvili (KP) equation uxt -6ux 2 +6uuxx -uxxxx -uyy -uzz = 0. By using this method, an explicit numerical solution is calculated in the form of a convergent power series with easily computable components. To illustrate the application of this method numerical results are derived by using the calculated components of the homotopy perturbation series. The numerical solutions are compared with the known analytical solutions. Results derived from our method are shown graphically.

Spatial complexity of solutions of higher order partial differential equations

NASA Astrophysics Data System (ADS)

Kukavica, Igor

2004-03-01

We address spatial oscillation properties of solutions of higher order parabolic partial differential equations. In the case of the Kuramoto-Sivashinsky equation ut + uxxxx + uxx + u ux = 0, we prove that for solutions u on the global attractor, the quantity card {x epsi [0, L]:u(x, t) = lgr}, where L > 0 is the spatial period, can be bounded by a polynomial function of L for all \\lambda\\in{\\Bbb R} . A similar property is proven for a general higher order partial differential equation u_t+(-1)^{s}\\partial_x^{2s}u+ \\sum_{k=0}^{2s-1}v_k(x,t)\\partial_x^k u =0 .

A New Mathematical and Computational Framework for BVPs and IVPs in Solids, Fluids, Gases and their Interactions

DTIC Science & Technology

2015-02-04

their numerical solutions for solid-liquid and liquid-solid phase transition: In the third area of research we consider development of mathematical models...momentum must be equal to the sum of the forces acting on the volume of matter) in terms of a dissipative force (the third term in (I.71)). Using (I.70...case, the momentum and constitutive equations (in the absence of body forces) in the x1-coordinate direction are ρ 0 ∂2ux1 ∂t2 + ∂p ∂x1 − ∂( dσx1x1

UW VLSI chip tester

NASA Astrophysics Data System (ADS)

McKenzie, Neil

1989-12-01

We present a design for a low-cost, functional VLSI chip tester. It is based on the Apple MacIntosh II personal computer. It tests chips that have up to 128 pins. All pin drivers of the tester are bidirectional; each pin is programmed independently as an input or an output. The tester can test both static and dynamic chips. Rudimentary speed testing is provided. Chips are tested by executing C programs written by the user. A software library is provided for program development. Tests run under both the Mac Operating System and A/UX. The design is implemented using Xilinx Logic Cell Arrays. Price/performance tradeoffs are discussed.

RR Lyrae in the UMi dSph Galaxy

NASA Astrophysics Data System (ADS)

Kuehn, Charles; Kinemuchi, Karen; Jeffery, Elizabeth; Grabowski, Kathleen; Nemec, James; Herrera, Daniel

2018-01-01

Over the past two years we have obtained observations of the Ursa Minor dwarf spheroidal galaxy with the goal of completing an updated catalog of the variable stars in the dwarf galaxy. In addition to finding new variable stars, this updated catalog will allow us to look at period changes in the variables and to determine stellar characteristic for the RR Lyrae stars in the dSph. We will compare the RR Lyrae stellar characteristics to other RR Lyrae stars found in the Local Group dSph galaxies; these comparisons can give us insights to the near-field cosmology of the Local Group. In this poster we present our updated catalog of RR Lyrae stars in the UMi dSph; the updated catalog includes Fourier decomposition parameters, metallicities, and other physical properties for the RR Lyrae stars.

The 1993 Finnish Interdisciplinary Seminar on SETI - A review of aims, approaches and conclusions

NASA Astrophysics Data System (ADS)

Seppanen, Jouko

1993-10-01

The communications of the International Interdisciplinary Seminar on SETI, held on March 6-7, 1993 in Vantaa, Finland, are reviewed and the contents and conclusions of papers summarized. The seminar was organized jointly by the Finnish Artificial Intelligence Society (FAIS), Finnish Astronomical Society, Ursa Astronomical Association and Heureka - The Finnish Science Centre. As the ninth in a series of intelligence-related seminars of FAIS, SETI was chosen as the topic for spring 1993, noting the new ten year NASA SETI program HRMS (High Resolution Micro-wave Survey), commenced on Columbus Day, October 12, 1992. The aims and the interdisciplinary format of the seminar are described, the main results and conclusions of papers are restated, and the seminar publications introduced. The summaries of papers are based on their abstracts and contain excerpts from texts.

Detection of a Compact Radio Source near the Center of a Gravitational Lens: Quasar Image or Galactic Core?

PubMed

Gorenstein, M V; Shapiro, I I; Cohen, N L; Corey, B E; Falco, E E; Marcaide, J M; Rogers, A E; Whitney, A R; Porcas, R W; Preston, R A; Rius, A

1983-01-07

By use of a new, very sensitive interferometric system, a faint, compact radio source has been detected near the center of the galaxy that acts as the main part of a gravitational lens. This lens forms two previously discovered images of the quasar Q09S7+561, which lies in the direction of the constellation Ursa Major. The newly detected source has a core smaller than 0.002 arc second in diameter with a flux density of 0.6 +/- 0.1 millijansky at the 13-centimeter wavelength of the radio observations. This source could be the predicted third image of the transparent gravitational lens, the central core of the galaxy, or some combination of the two. It is not yet possible to choose reliably between these alternatives.

A 60-NIGHT Campaign on Dwarf Novae - Part One - Photometric Variability of Su-Ursae and Yz-Cancri

NASA Astrophysics Data System (ADS)

van Paradijs, J.; Charles, P. A.; Harlaftis, E. T.; Arevalo, M. J.; Baruch, J. E. F.; Callanan, P. J.; Casares, J.; Dhillon, V. S.; Gimenez, A.; Gonzalez, R.; Matinez-Pais, I. G.; Jones, D. H. P.; Hassall, B. J. M.; Hellier, C.; Kidger, M. R.; Lazaro, C.; Marsh, T. R.; Mason, K. O.; Mukai, K.; Naylor, T.; Reglero, V.; Rutten, R. G. M.; Smith, R. C.

1994-04-01

A 60-night campaign on SU UMa, YZ Cnc and some secondary targets was carried out during 1988 December and 1989 January at the Observatorio del Roque de Los Muchachos (the 1988 International Time Project). The aim was to study the behaviour of these dwarf novae through their outburst cycle. Here we present the overall light curves of the main targets, SU UMa and YZ Cnc, which show that the optical fluxes continue to decrease after the end of the outburst. For YZ Cnc we find that, during quiescence, orbital variability is present, which may be interpreted as modulation caused by the bright-spot region. Near the end of an outburst, a weak, sinusoidal variation is observed; we discuss the possibility that this arises either from the secondary star or the accretion disc.

Pinwheel Looks 'Fab' in Infrared

NASA Technical Reports Server (NTRS)

2008-01-01

The tangled arms of the Pinwheel galaxy, otherwise known as Messier 101, are decked out in red in this new infrared image from NASA's Spitzer Space Telescope.

The Pinwheel galaxy is located 27 million light-years away in the constellation Ursa Major. It is what's called a flocculent spiral, which means that its spiral arms are not well defined.

The red color shows the dust, while the blue glow around the galaxy is from starlight.

In this infrared composite, blue indicates light with a wavelength of 3.6 microns, green corresponds to 4.5 microns, and red to 5.8 and 8.0 microns. The contribution from starlight (measured at 3.6 microns) has been subtracted from the 5.8- and 8-micron images to enhance the visibility of the dust features.

Phosphorus Chemistry in Oxygen Rich Stars

NASA Astrophysics Data System (ADS)

Bernal, Jacob; Schmidt, Deborah; Anderson, Julie; Ziurys, Lucy M.

2017-06-01

Observations of PO and PN have been carried out at the Arizona Radio Observatory at 1, 2, and 3 mm. Multiple transitions of PO and PN have been detected towards the O-rich AGB stars TX Cam and RCas. Data obtained toward supergiant stars VY Canis Majoris and NML Cyg have also been analyzed. Abundances were obtained for these molecules in all four objects using the radiative transfer code ESCAPADE, which is suitable for symmetric and asymmetric stellar outflows. The abundances of PN and PO were found to be in the range 10^{-8} - 10^{-7} relative to H_{2}. While PN appears to be a parent molecule formed by LTE chemistry near the stellar photosphere, PO appears to be created further out from the star at r > 400 R_*.

Ultraviolet photometry from the Orbiting Astronomical Observatory. XXVIII - Ultraviolet light curves for Alpha Lupi and BW Vulpeculae

NASA Technical Reports Server (NTRS)

Lesh, J. R.

1978-01-01

Photometric data from the Wisconsin Experiment Package on OAO-2 have been used to construct light curves at three ultraviolet wavelengths for Alpha Lup and at seven wavelengths for BW Vul. Both stars are well-known variables of the Beta Cephei (Beta Canis Majoris) type. The light curves for Alpha Lup are in good agreement with the radial-velocity period. A temperature variation of 400-500 K is derived. The BW Vul light curves confirm recent ephemerides based on a secularly varying period and show a stillstand near light maximum at some wavelengths. Both stars exhibit increasing light amplitude at the shortest ultraviolet wavelengths. There is little evidence for cycle-to-cycle variations on a time scale of the order of 1 day.

Carbon Chemistry in the Envelope of VY Canis Majoris: Implications for Oxygen-Rich Evolved Stars

NASA Astrophysics Data System (ADS)

Ziurys, L. M.; Tenenbaum, E. D.; Pulliam, R. L.; Woolf, N. J.; Milam, S. N.

2009-04-01

Observations of the carbon-bearing molecules CO, HCN, CS, HNC, CN, and HCO+ have been conducted toward the circumstellar envelope of the oxygen-rich red supergiant star, VY Canis Majoris (VY CMa), using the Arizona Radio Observatory (ARO). CO and HCN were also observed toward the O-rich shells of NML Cyg, TX Cam, IK Tau, and W Hya. Rotational transitions of these species at 1 mm, 0.8 mm, and 0.4 mm were measured with the ARO Submillimeter Telescope, including the J = 6 → 5 line of CO at 691 GHz toward TX Cam and W Hya. The ARO 12 m was used for 2 mm and 3 mm observations. Four transitions were observed for HCO+ in VY CMa, the first definitive identification of this ion in a circumstellar envelope. Molecular line profiles from VY CMa are complex, indicating three separate outflows: a roughly spherical flow and separate red- and blueshifted winds, as suggested by earlier observations. Spectra from the other sources appear to trace a single outflow component. The line data were modeled with a radiative transfer code to establish molecular abundances relative to H2 and source distributions. Abundances for CO derived for these objects vary over an order of magnitude, f ~ 0.4-5 × 10-4, with the lower values corresponding to the supergiants. For HCN, a similar range in abundance is found (f ~ 0.9-9 × 10-6), with no obvious dependence on the mass-loss rate. In VY CMa, HCO+ is present in all three outflows with f ~ 0.4-1.6 × 10-8 and a spatial extent similar to that of CO. HNC is found only in the red- and blueshifted components with [HCN]/[HNC] ~ 150-190, while [CN]/[HCN] ~ 0.01 in the spherical flow. All three velocity components are traced in CS, which has a confined spatial distribution and f ~ 2-6 × 10-7. These observations suggest that carbon-bearing molecules in O-rich shells are produced by a combination of photospheric shocks and photochemistry. Shocks may play a more prominent role in the supergiants because of their macroturbulent velocities.

Freely Drifting Swallow Float Array: May 1987 Trip Report

DTIC Science & Technology

1988-05-01

co’-4 v-4~ I00 I.U I6z oJy 2ZIWO Is Y)L Figur X.4x ca C)CD U) Lo Cc r(no _0 I IC VV ~.N L) Figue X. 4bD !K U.n a1 u iP K ( o 0) 1 1(: I.,L Il 4, U ch...La. Pw ~’(rh I y- El - tD Efp KL Cr) -- - If MaIKuOOPzlwO FigreXr)b. -~ jtn x4 a(I-~)WIo u- _0 c ca CO _ -4 I’a) Fic’uX15~ 4-0C es ~ -J-L p -S.7e -f-i

Pre-Deployment Handbook Papua New Guinea

DTIC Science & Technology

2014-03-01

ai M or eh ea d W ea m Ku pi an o A ng or am Te le fo m in Ta la se a G lo uc es te r...rit ai n B ou ga in vi lle C ho is eu l S an ta Y sa be l W oo dl ar k P oc kl in gt on R ee f D ’E nt re ca st ea ux Is la nd s Lo ui si ad e A...rc hi pe la go B is m a rc k A rc h ip e la g o Ta sk ul K ar ka r Lo ng K iw ai U

Word Frequency Analysis. MOS: 45K. Skill Levels 1 & 2.

DTIC Science & Technology

1981-05-01

ACCESSION No. 3. RECIPIENT’S CATALOG 14UMBER 4. TITLE...change. Accession For DTIC TAB [ Ux~amo~ed []Just iriction D_.st ribution, pYAvai labilit 7 codt.s A o Avi ado S* HEADQUARTERS DATA CONTROL NMEIII m...6 (’N "N 6 . "!4 ON Cf c4:’i 6 Cu-L /’Uc.RE" L ~u:ir 6 6 Z72 : SS7 2 t N 6’vy \\ .C.1F? 6 H% ’ e y N ’CIo6’ 6 A fg; 6 l~ 14 6 r I 5’J 6 ’~1!6 ’",13P 6

Improving UXS Network Availability with Asymmetric Polarized MIMO

DTIC Science & Technology

2013-06-01

physical area PA of the antenna by the efficiency of the aperture ( 0 1ap  ) as given by 2 4 ap PG A    . (16) For example, uniformly...2/3 48 -66 5 16-QAM 3/ 4 36 -70 4 16-QAM 1/2 24 -74 3 QPSK 3/ 4 18 -77 2 QPSK 1/2 12 -79 1 BPSK 3/ 4 9 -81 0 BPSK 1/2 6 -82 The standard only...used with the downlink receiver with 2 inputs ( 2 2 ) or 4 inputs ( 2 2p ). For the 2 2 configuration, the 3 dB power loss when 0 5.  is a

Usability Testing as a Method to Refine a Health Sciences Library Website.

PubMed

Denton, Andrea H; Moody, David A; Bennett, Jason C

2016-01-01

User testing, a method of assessing website usability, can be a cost-effective and easily administered process to collect information about a website's effectiveness. A user experience (UX) team at an academic health sciences library has employed user testing for over three years to help refine the library's home page. Test methodology used in-person testers using the "think aloud" method to complete tasks on the home page. Review of test results revealed problem areas of the design and redesign; further testing was effective in refining the page. User testing has proved to be a valuable method to engage users and provide feedback to continually improve the library's home page.

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.

Evolution in slow motion

NASA Image and Video Library

2015-09-14

It is known today that merging galaxies play a large role in the evolution of galaxies and the formation of elliptical galaxies in particular. However there are only a few merging systems close enough to be observed in depth. The pair of interacting galaxies picture seen here — known as NGC 3921 — is one of these systems. NGC 3921 — found in the constellation of Ursa Major (The Great Bear) — is an interacting pair of disc galaxies in the late stages of its merger. Observations show that both of the galaxies involved were about the same mass and collided about 700 million years ago. You can see clearly in this image the disturbed morphology, tails and loops characteristic of a post-merger. The clash of galaxies caused a rush of star formation and previous Hubble observations showed over 1000 bright, young star clusters bursting to life at the heart of the galaxy pair.

An ancient eye test--using the stars.

PubMed

Bohigian, George M

2008-01-01

Vision testing in ancient times was as important as it is today. The predominant vision testing in some cultures was the recognition and identification of constellations and celestial bodies of the night sky. A common ancient naked eye test used the double star of the Big Dipper in the constellation Ursa Major or the Big Bear. The second star from the end of the handle of the Big Dipper is an optical double star. The ability to perceive this separation of these two stars, Mizar and Alcor, was considered a test of good vision and was called the "test" or presently the Arab Eye Test. This article is the first report of the correlation of this ancient eye test to the 20/20 line in the current Snellen visual acuity test. This article describes the astronomy, origin, history, and the practicality of this test and how it correlates with the present day Snellen visual acuity test.

Long-Wavelength Infrared Views of Messier 81

NASA Technical Reports Server (NTRS)

2003-01-01

The magnificent and dusty spiral arms of the nearby galaxy Messier 81 are highlighted in these NASA Spitzer Space Telescope images. Located in the northern constellation of Ursa Major (which also includes the Big Dipper), this galaxy is easily visible through binoculars or a small telescope. M81 is located at a distance of 12 million light-years.

The three-panel mosaic is a series of images obtained with the multiband imaging photometer for Spitzer. Thermal infrared emission at 24 microns (top), 70 microns (center) and 160 microns (bottom) is shown in the images. Note that the effective spatial resolution degrades as ones moves to longer wavelengths.

At these wavelengths, Spitzer sees the dust, rather than the stars, within the disc of silicates and carbonaceous grains. It is well-mixed with gas, which is best seen at radio wavelengths, to form the essential ingredients for future star formation.

Potential, velocity, and density fields from redshift-distance samples: Application - Cosmography within 6000 kilometers per second

NASA Technical Reports Server (NTRS)

Bertschinger, Edmund; Dekel, Avishai; Faber, Sandra M.; Dressler, Alan; Burstein, David

1990-01-01

A potential flow reconstruction algorithm has been applied to the real universe to reconstruct the three-dimensional potential, velocity, and mass density fields smoothed on large scales. The results are shown as maps of these fields, revealing the three-dimensional structure within 6000 km/s distance from the Local Group. The dominant structure is an extended deep potential well in the Hydra-Centaurus region, stretching across the Galactic plane toward Pavo, broadly confirming the Great Attractor (GA) model of Lynden-Bell et al. (1988). The Local Supercluster appears to be an extended ridge on the near flank of the GA, proceeding through the Virgo Southern Extension to the Virgo and Ursa Major clusters. The Virgo cluster and the Local Group are both falling toward the bottom of the GA potential well with peculiar velocities of 658 + or - 121 km/s and 565 + or - 125 km/s, respectively.

http://www.nasa.gov/feature/goddard/2016/hubble-team-breaks-cosmic-distance-record

NASA Image and Video Library

2016-03-03

By pushing NASA’s Hubble Space Telescope to its limits, an international team of astronomers has shattered the cosmic distance record by measuring the farthest galaxy ever seen in the universe. This surprisingly bright infant galaxy, named GN-z11, is seen as it was 13.4 billion years in the past, just 400 million years after the Big Bang. GN-z11 is located in the direction of the constellation of Ursa Major. Read more: go.nasa.gov/1oSqHad NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The first linear polarization spectra of Wolf-Rayet stars in the ultraviolet - EZ Canis Majoris and Theta Muscae

NASA Technical Reports Server (NTRS)

Schulte-Ladbeck, R. E.; Nordsieck, K. H.; Code, A. D.; Anderson, C. M.; Babler, B. L.; Bjorkman, K. S.; Clayton, G. C.; Magalhaes, A. M.; Meade, M. R.; Shepherd, D.

1992-01-01

During the 1990 December Astro-1 Space Shuttle mission, spectropolarimetry was conducted in the wavelength region from 1400 to 3200 A of the Wolf-Rayet stars EZ CMa (WN5) and Theta Mus (WC6 + O9.5I) with the Wisconsin Ultraviolet Photo-Polarimeter Experiment. The UV polarization of EZ CMa displays features which correspond to emission lines. This indicates a large, about 0.8 percent, intrinsic UV-continuum polarization, and provides further evidence that the wind of EZ CMa is highly distorted. The polarization of Theta Mus does not change across emission lines, or the strong interstellar 2200 A feature. The polarization decreases smoothly to shorter wavelengths, at constant position angle. The combined UV-optical polarization spectrum of Theta Mus can be described well with interstellar polarization following a Serkowski law.

Expanding the Chemistry of Actinide Metallocene Bromides. Synthesis, Properties and Molecular Structures of the Tetravalent and Trivalent Uranium Bromide Complexes: (C 5Me 4R) 2UBr 2, (C 5Me 4R) 2U(O-2,6- iPr 2C 6H 3)(Br), and [K(THF)][(C 5Me 4R) 2UBr 2] (R = Me, Et)

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

Lichtscheidl, Alejandro Gaston; Pagano, Justin K.; Scott, Brian Lindley

The organometallic uranium species (C 5Me 4R) 2UBr 2 (R = Me, Et) were obtained by treating their chloride analogues (C 5Me 4R) 2UCl 2 (R = Me, Et) with Me 3SiBr. Treatment of (C 5Me 4R) 2UCl 2 and (C 5Me 4R) 2UBr 2 (R = Me, Et) with K(O-2,6- iPr 2C 6H 3) afforded the halide aryloxide mixed-ligand complexes (C 5Me 4R) 2U(O-2,6- iPr 2C 6H 3)(X) (R = Me, Et; X = Cl, Br). Complexes (C 5Me 4R) 2U(O-2,6- iPr 2C 6H 3)(Br) (R = Me, Et) can also be synthesized by treating (C 5Me 4R) 2U(O-2,6-more » iPr 2C 6H 3)(Cl) (R = Me, Et) with Me 3SiBr, respectively. Reduction of (C 5Me 4R) 2UCl 2 and (C 5Me 4R) 2UBr 2 (R = Me, Et) with KC 8 led to isolation of uranium(III) “ate” species [K(THF)][(C 5Me 5) 2UX 2] (X = Cl, Br) and [K(THF) 0.5][(C 5Me 4Et) 2UX 2] (X = Cl, Br), which can be converted to the neutral complexes (C 5Me 4R) 2U[N(SiMe 3) 2] (R = Me, Et). Analyses by nuclear magnetic resonance spectroscopy, X-ray crystallography, and elemental analysis are also presented.« less

Characterization of Antixenosis in Soybean Genotypes to Bemisia tabaci (Hemiptera: Aleyrodidae) Biotype B.

PubMed

Baldin, E L L; Cruz, P L; Morando, R; Silva, I F; Bentivenha, J P F; Tozin, L R S; Rodrigues, T M

2017-08-01

Bemisia tabaci biotype B (Gennadius) is one of the most important soybean pest worldwide. Herein, 15 soybean genotypes were evaluated, to characterize the occurrence of antixenosis to B. tabaci biotype B. Initially, a multiple-choice test with all genotypes was carried out, evaluating the settling and oviposition preference at 3 d after infestation, and the colonization by nymphs after 48 d of infestation. Subsequently, a no-choice test, using 14 genotypes, was conducted with infested plants individually, and the number of eggs was counted after 72 h. Then, 10 genotypes were selected (indicative of resistance and susceptibility), which were evaluated for whitefly settling 24, 48, and 72 h after infestation and for oviposition 72 h after infestation. The trichomes of the leaflets were characterized for density, size, and inclination to establish possible correlations with the settling and oviposition in the genotypes. In the first multiple-choice test, involving 15 genotypes, 'IAC-17,' 'IAC-19,' and UX-2569-159 expressed antixenosis against B. tabaci. 'Jackson,' 'P98Y11,' and PI-229358 exhibited the same behavior in the no-choice test. In the multiple-choice test, 'Jackson,' 'P98Y11,' and 'TMG1176 RR' were the least attractive and least used for oviposition. The antixenosis shown by 'Jackson,' 'P98Y11,' and PI-229358 may be related to the characteristics of the trichomes (lower density and inclined). Based on the experiments carried out, 'IAC-17,' 'IAC-19,' 'Jackson,' 'P98Y11,' PI-229358, TMG1176 RR, and UX-2569-159 are considered promising for resistance to B. tabaci biotype B and may be exploited in soybean breeding programs for resistance to insects. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Expanding the Chemistry of Actinide Metallocene Bromides. Synthesis, Properties and Molecular Structures of the Tetravalent and Trivalent Uranium Bromide Complexes: (C 5Me 4R) 2UBr 2, (C 5Me 4R) 2U(O-2,6- iPr 2C 6H 3)(Br), and [K(THF)][(C 5Me 4R) 2UBr 2] (R = Me, Et)

DOE PAGES

Lichtscheidl, Alejandro Gaston; Pagano, Justin K.; Scott, Brian Lindley; ...

2016-01-06

The organometallic uranium species (C 5Me 4R) 2UBr 2 (R = Me, Et) were obtained by treating their chloride analogues (C 5Me 4R) 2UCl 2 (R = Me, Et) with Me 3SiBr. Treatment of (C 5Me 4R) 2UCl 2 and (C 5Me 4R) 2UBr 2 (R = Me, Et) with K(O-2,6- iPr 2C 6H 3) afforded the halide aryloxide mixed-ligand complexes (C 5Me 4R) 2U(O-2,6- iPr 2C 6H 3)(X) (R = Me, Et; X = Cl, Br). Complexes (C 5Me 4R) 2U(O-2,6- iPr 2C 6H 3)(Br) (R = Me, Et) can also be synthesized by treating (C 5Me 4R) 2U(O-2,6-more » iPr 2C 6H 3)(Cl) (R = Me, Et) with Me 3SiBr, respectively. Reduction of (C 5Me 4R) 2UCl 2 and (C 5Me 4R) 2UBr 2 (R = Me, Et) with KC 8 led to isolation of uranium(III) “ate” species [K(THF)][(C 5Me 5) 2UX 2] (X = Cl, Br) and [K(THF) 0.5][(C 5Me 4Et) 2UX 2] (X = Cl, Br), which can be converted to the neutral complexes (C 5Me 4R) 2U[N(SiMe 3) 2] (R = Me, Et). Analyses by nuclear magnetic resonance spectroscopy, X-ray crystallography, and elemental analysis are also presented.« less

URSA MAIOR: a One Liter Nanosatellite Bus for Low Cost Access to Space

NASA Astrophysics Data System (ADS)

Santoni, F.

One of the main limitations in the access to space for developing countries is the economical effort typically required by space missions. Secondly, space activity is a field of very high technology, requiring technical skills, education and practice, at a level which is seldom reached by developing countries. Interventions aimed to facilitate access to space for developing countries should be focussed primarily on the missions allowing access to space at reasonable cost. Moreover, perhaps more importantly, they should emphasize conducting the mission design, construction, ground testing and operation in orbit as an open activity, accessible to developing countries personnel, in order to set up an education process, which is not just selling a product ready satellite. Universities could have a very important role in this activity. Many Universities around the world have designed, built and launched small satellites. Università di Roma "La Sapienza" set up a program for the construction of small satellites in an academic environment, involving directly the students in the design, construction, ground testing and operation in orbit. The first satellite built in the framework of this program, UNISAT, was successfully launched in September 2000. The second, UNISAT-2, initially scheduled for launch in 2001, has been delayed by the launch provider to late 2002. These two satellites, based on a modular design, emphasizing ease of construction and assembly, weight roughly 10 kg. The realization of these satellites was made possible within the regular financing given to university research programs, keeping down cost by the use of commercial off the shelf components instead of space rated ones. The microsatellite experience at Università di Roma "La Sapienza", is going further with the development of a new nanosatellite bus, URSA MAIOR (Università di Roma "la SApienza" Micro Autonomous Imager in ORbit), aiming at cutting down cost and possibly improving performance. The whole satellite has a volume of one liter and a target weight of one kilogram. It can support small scientific missions, such as Earth imaging, and, potentially, small communications payloads. All the on-board components are commercial off the shelf, including solar panels, completely assembled in the University laboratories. Commercial Li-Ion batteries are the energy storage device. Three axis attitude stabilization is provided by a bias momentum wheel, with magnetic coils for active nutation damping and pointing control. Academic personnel and students are involved in the whole process of the nanosatellite design, construction and ground test. All the phases of the projects are open to the participation of the students, contributing ideas and solution to the technical problems, under the supervision of the academic staff. All the subsystems and components are designed to be assembled in a normally equipped electronics laboratory, without any potentially harmful materials or operations. For example the Li-Ion battery pack have been assembled following a procedure, primarily focussed on ease of integration and assembly by not experienced people, such as students, in a normally equipped University electronics laboratory. Packing materials were selected with no special requirements in terms of toxicity control, potential harmful operations, environmental cleanliness, or expensive curing machines. The space education experience made at Università di Roam "La Sapienza", with all the phases of the space program opened to students, realizing small satellites with small economical budgets seems to be a useful tool to give access to space to developing countries. These could have a piece of hardware in space at reachable costs, realizing small earth imaging or communication missions, and at the same time could obtain space education through hands-on experience, filling, at least in part, the technological gap. The paper describes the nanosatellite bus URSA MAIOR in some detail, showing how it could be exploited as useful tool to give developing countries access to space, as well as space education.

KWIK Smoke Obscuration Model: User’s Guide.

DTIC Science & Technology

1982-09-01

t ’ustr ( td I IK,j) 384: prt 3o :: pr t 6 k AC 1-4G" 36~b : pr t " ~ L 3b7: if j~i;prt &t(t1,] 3 8 8: it J=2;pr. "&str(Zjl,1,KI) 3 0 9: j~r t "I 39u...t.2~t71. * j3 3 2u: w r t 7uX ,"i(Lz~j i21iJ "c3wt70, )i: lnt 4 5X, "irI I U uIL - = 01 17.2;wrt 701,kq3 j~b: Lirt. 45x,"a..~c4 uAT - LiLY = g,t4.2

Guidelines and Data to Support Plans for Reallocating Food during Crisis Relocation. Regional Appendix. FEMA Region VII,

DTIC Science & Technology

1982-09-01

using approximation techniques developed in earlier SYSTAN work (Food Systn.em Suport of the Rclocntion Strategy, September, 1975). Using this technique...INC VOONE IA 1 0 0 0 1 0 5,000 SUFER VALU STORES INC DES MOINES IA I 0 0 1 0 0 3,000 COUNTY TOTAL: 3 1 0 1 1 0 3,750 M;,HASKA FARE!AY STORES INC SOCNE...5,000 SUFER VALU SCPES INC DES tFOINES IA 1 0 0 1 0 0 3,000 U’lITED A G SIORES OMAHA NE 3 3 0 0 0 0 2,250 COUNTY TOTAL: 6 3 0 1 2 0 15,250 SI[’UX

LYNX: A Linked Eulerian and Lagrangian Code. Volume II. LYNX Computer Listing

DTIC Science & Technology

1975-11-01

177« 178« 179» ISO* 18|» 182« 183» IBM * 185* 1B6« 187» 198« 189« 190« |f|i 192» 193« 194» 195» 196« 197» 198» 199* 200» 201...XPLC ID) ,Y(JD) ,TAUI ID) ,YB(IJD) .FBI IJD) ,T 1 3B ( ID ) • XCT I IJD) »VOBUjD» ,ZZ(NN0IM) ,VV(NND1M) »OBFUL •BETA tAP •OTCP iTP ...CELL CONTAINING PARTICLE NO I. •OB IOUFUL •BETA »AP •UTCP iTP •COMPEN ,SHEN •YP1 »YP2 •KMAX ,KBAR • 1JMA< ,IK»UX

On the wind geometry of the Wolf-Rayet star EZ Canis Majoris

NASA Technical Reports Server (NTRS)

Schulte-Ladbeck, R. E.; Nordsieck, K. H.; Taylor, M.; Nook, M. A.; Bjorkman, K. S.; Magalhaes, A. M.; Anderson, C. M.

1991-01-01

Recent models of Wolf-Rayet star winds have been tailored to EZ CMa, and make predictions of the envelope structure and location of line-emitting regions. It is discussed how the wind structure of EZ CMa can be probed observationally through electron distribution integrals as measured by spectropolarimetry, and then present, analyze, and interpret a time-dependent spectropolarimetric data set of EZ CMa. The observations further the view of an electron-scattering wind that is axisymmetric, rotating, and expanding, with a variable mass-loss rate being responsible for the quasi-periodic polarimetric variability. It is demonstrated that the emission lines of EZ CMa are partially polarized, indicating that line photons are electron-scattered in the wind. The polarization in N V lambda 4945 and N IV lambda 4058 is observed to be larger than that of He II lambda 4686 and He I lambda 5876, as expected from ionization stratification.

Submillimeter vibrationally excited water emission from the peculiar red supergiant VY Canis Majoris

NASA Astrophysics Data System (ADS)

Menten, K. M.; Philipp, S. D.; Güsten, R.; Alcolea, J.; Polehampton, E. T.; Brünken, S.

2006-08-01

Context: .Vibrationally excited emission from the SiO and H2O molecules probes the innermost circumstellar envelopes of oxygen-rich red giant and supergiant stars. VY CMa is the most prolific known emission source in these molecules. Aims: .Observations were made to search for rotational lines in the lowest vibrationally excited state of H2O. Methods: .The APEX telescope was used for observations of H2O lines at frequencies around 300 GHz. Results: .Two vibrationally excited H2O lines were detected, a third one could not be found. In one of the lines we find evidence for weak maser action, similar to known (sub)millimeter ν2 = 1 lines. We find that the other line's intensity is consistent with thermal excitation by the circumstellar infrared radiation field. Several SiO lines were detected together with the H2O lines.

Wide-field Infrared Survey Explorer

NASA Technical Reports Server (NTRS)

Padgett, Deborah

2012-01-01

We present WISE (Wide-field Infrared Survey Explorer) mid-infrared photometry of young stellar object candidates in the Canis Majoris clouds at a distance of 1 kpc. WISE has identified 682 objects with apparent 12 and 22 micron excess emission in a 7 deg x 10 deg field around the CMa Rl cloud . While a substantial fraction of these candidates are likely galaxies, AGB stars, and artifacts from confusion along the galactic plane, others are part of a spectacular cluster of YSOs imaged by WISE along a dark filament in the R1 cloud. Palomar Double Spectrograph observations of several sources in this cluster confirm their identity as young A and B stars with strong emission lines. In this contribution, we plot the optical -mid-infrared spectral energy distribution for the WISE YSO candidates and discuss potential contaminants to the sample . The data demonstrate the utility of WISE in performing wide-area surveys for young stellar objects.

The Dual-channel Extreme Ultraviolet Continuum Experiment: Sounding Rocket EUV Observations of Local B Stars to Determine Their Potential for Supplying Intergalactic Ionizing Radiation

NASA Astrophysics Data System (ADS)

Erickson, Nicholas; Green, James C.; France, Kevin; Stocke, John T.; Nell, Nicholas

2018-06-01

We describe the scientific motivation and technical development of the Dual-channel Extreme Ultraviolet Continuum Experiment (DEUCE). DEUCE is a sounding rocket payload designed to obtain the first flux-calibrated spectra of two nearby B stars in the EUV 650-1150Å bandpass. This measurement will help in understanding the ionizing flux output of hot B stars, calibrating stellar models and commenting on the potential contribution of such stars to reionization. DEUCE consists of a grazing incidence Wolter II telescope, a normal incidence holographic grating, and the largest (8” x 8”) microchannel plate detector ever flown in space, covering the 650-1150Å band in medium and low resolution channels. DEUCE will launch on December 1, 2018 as NASA/CU sounding rocket mission 36.331 UG, observing Epsilon Canis Majoris, a B2 II star.

A revised catalog of CfA galaxy groups in the Virgo/Great Attractor flow field

NASA Technical Reports Server (NTRS)

Nolthenius, Richard

1993-01-01

A new identification of groups and clusters in the CfAl Catalog of Huchra, et al. (1983) is presented, using a percolation algorithm to identify density enhancements. The procedure differs from that of the original Geller and Huchra (1983; GH) catalog in several important respects; galaxy distances are calculated from the Virgo-Great Attractor flow model of Faber and Burnstein (1988), the adopted distance linkage criteria is only approx. 1/4 as large as in the Geller and Huchra catalog, the sky link relation is taken from Nolthenius and White (1987), correction for interstellar extinction is included, and 'by-hand' adjustments to group memberships are made in the complex regions of Virgo/Coma I/Ursa Major and Coma/A1367 (to allow for varying group velocity dispersions and to trim unphysical 'spider arms'). Since flow model distances are poorly determined in these same regions, available distances from the IR Tully-Fisher planetary nebula luminosity function and surface brightness resolution methods are adopted if possible.

Outskirts of Local Group Dwarf Galaxies Revealed by Subaru Hyper Suprime-Cam

NASA Astrophysics Data System (ADS)

Komiyama, Yutaka

2017-03-01

Local Group galaxies are important targets since their stellar populations can be resolved, and their properties can be investigated in detail with the help of stellar evolutionary models. The newly-built instrument for the 8.2m Subaru Telescope, Hyper Suprime-Cam (HSC), which has a 1 Giga pixel CCD camera with 1.5 degrees field of view, is the best instrument for observing Local Group galaxies. We have carried out a survey for Local Group dwarf galaxies using HSC aiming to shed light on the outskirts of these galaxies. The survey covers target galaxies out beyond the tidal radii down to a depth unexplored by previous surveys. Thanks to the high spatial resolution and high sensitivity provided by the Subaru Telescope, we are able to investigate properties such as spatial distribution and stellar population from the very center of galaxies to the outskirts. In this article, I will show results for the dwarf irregular galaxy NGC 6822 and the dwarf spheroidal galaxy Ursa Minor.

Fast-Neutron Activation of Long-Lived Isotopes in Enriched Ge

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

Elliott, Steven R.; Guiseppe, Vincente; LaRoque, B. H.

2010-11-16

We measured the production of 57Co, 54Mn, 68Ge, 65Zn, and 60Co in an sample of Ge enriched in isotope 76 due to high-energy neutron interactions. These isotopes are critical in understanding background in Ge detectors used for double-beta decay experiments. These isotopes are produced by cosmogenic-neutron interactions in the detectors while they reside on the Earth's surface. We compared the measured production to that predicted by cross-section calculations based on CEM03.02. The cross section calculations over-predict our measurements by approximately a factor of 2-3 depending on isotope. We then use the measured cosmic-ray neutron ux and our results to predictmore » the cosmogenic production rate with an accuracy near 15%.« less

Unusual equilibration of a particle in a potential with a thermal wall

NASA Astrophysics Data System (ADS)

Bhat, Deepak; Sabhapandit, Sanjib; Kundu, Anupam; Dhar, Abhishek

2017-11-01

We consider a particle in a one-dimensional box of length L, with a Maxwell bath at one end and a reflecting wall at the other end. Using a renewal approach, as well as directly solving the master equation, we show that the system exhibits a slow power law relaxation, with a logarithmic correction, towards the final equilibrium state. We extend the renewal approach to a class of confining potentials of the form U(x) \\propto x^α , x>0 , where we find that the relaxation is ∼ t-(α+2)/(α-2) for α >2 , with a logarithmic correction when (α+2)/(α-2) is an integer. For α <2 the relaxation is exponential. Interestingly for α=2 (harmonic potential) the localised bath cannot equilibrate the particle.

AGN Obscuration Through Dusty Infrared Dominated Flows. II. Multidimensional, Radiation-Hydrodynamics Modeling

NASA Technical Reports Server (NTRS)

Dorodnitsyn, Anton; Kallman, Tim; Bisno\\vatyiI-Kogan, Gennadyi

2011-01-01

We explore a detailed model in which the active galactic nucleus (AGN) obscuration results from the extinction of AGN radiation in a global ow driven by the pressure of infrared radiation on dust grains. We assume that external illumination by UV and soft X-rays of the dusty gas located at approximately 1pc away from the supermassive black hole is followed by a conversion of such radiation into IR. Using 2.5D, time-dependent radiation hydrodynamics simulations in a ux-limited di usion approximation we nd that the external illumination can support a geometrically thick obscuration via out ows driven by infrared radiation pressure in AGN with luminosities greater than 0:05 L(sub edd) and Compton optical depth, Tau(sub T) approx > & 1.

On the Propagation of Nonlinear Acoustic Waves in Viscous and Thermoviscous Fluids

DTIC Science & Technology

2012-01-01

continuity and momentum equations, which in 1D reduce to ϱt + uϱx + ϱux = 0, (6) ϱ(ut + uux) = −℘x +  4 3 µ + µB  uxx, (7) respectively, recalling that all...1F ′ −  1 − v2n v3−2nn  F = ϵβF 2 (n = 0, 1), (14) i.e., the associated ODEs of the former and latter are Bernoulli equations. Integrating these...12), are of the Bernoulli type, namely, (Red)−1F ′ −  1 − v2n vn  F = ϵ  1 2 n +  β − 1 2 n  v2n  F 2, (20) which when integrated yield the

Installation Restoration Program. Site Investigation Report. Volume 4. 152nd Tactical Reconnaissance Group, Nevada Air National Guard, Reno Cannon International Airport, Reno, Nevada

DTIC Science & Technology

1994-04-01

1597 SDG LA3 ID KaMBER COmOVouD lZXP PORN SP 443 m/m 442 u/x CALC LAB CALC LIMIT RLAIz R3LATrVZ 0 AD= I AIDO ERROR -BU AWN 1 1545 DF930308A21 DFTPP...1597 SAWPLZ SAM) E 0 CONPOUUD SPIKU 8 ANPLZ NATRIX M HD 15 mm M I0 MI D CAL APC NUMIER TYPE ADDED RESULT SPIKE t 1EA t VRI RPD VWi 1566 1545 1,4-DICKL...1597 E1DO LAB ID XMNDI CONPOUND ZXP PORN EPZC1176 u/s 1174 u/u CALC LAB CALC ILIMIT RELATIVE RELATIVE I ABUN I £303 ERROR 1545 B7930307356 3PB y y

Department of Defense Data Model, Version 1, Fy 1998, Volume 5.

DTIC Science & Technology

1998-05-31

TM E LULU LU UJ < 15 LU H tgt hhhh °-11 UJ < i? .55 1 Ul HLU LU 111 Ul Ul a...CC DC DC DC DC TDC < (3 UJ O o oaoooo E 0(5 O O OOO o < UJ o _l UJ UJ UJ UJ UJ UJ 9 o zes o o a a a cj oao ooooo o U. LL U. U. U. U- U- u. u...X UJ E N TM FI E R C C A TI O E JO 1- ><-’ < 3 ui 9 a OO zn< _i < 0 (5B O ioo O X O 0 _i CO _l< z 0 z zzz 0 000 1- 1- l-l- 0 0

Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group

NASA Astrophysics Data System (ADS)

King, Jeremy R.; Villarreal, Adam R.; Soderblom, David R.; Gulliver, Austin F.; Adelman, Saul J.

2003-04-01

Utilizing Hipparcos parallaxes, original radial velocities and recent literature values, new Ca II H and K emission measurements, literature-based abundance estimates, and updated photometry (including recent resolved measurements of close doubles), we revisit the Ursa Major moving group membership status of some 220 stars to produce a final clean list of nearly 60 assured members, based on kinematic and photometric criteria. Scatter in the velocity dispersions and H-R diagram is correlated with trial activity-based membership assignments, indicating the usefulness of criteria based on photometric and chromospheric emission to examine membership. Closer inspection, however, shows that activity is considerably more robust at excluding membership, failing to do so only for <=15% of objects, perhaps considerably less. Our UMa members demonstrate nonzero vertex deviation in the Bottlinger diagram, behavior seen in older and recent studies of nearby young disk stars and perhaps related to Galactic spiral structure. Comparison of isochrones and our final UMa group members indicates an age of 500+/-100 Myr, some 200 Myr older than the canonically quoted UMa age. Our UMa kinematic/photometric members' mean chromospheric emission levels, rotational velocities, and scatter therein are indistinguishable from values in the Hyades and smaller than those evinced by members of the younger Pleiades and M34 clusters, suggesting these characteristics decline rapidly with age over 200-500 Myr. None of our UMa members demonstrate inordinately low absolute values of chromospheric emission, but several may show residual fluxes a factor of >=2 below a Hyades-defined lower envelope. If one defines a Maunder-like minimum in a relative sense, then the UMa results may suggest that solar-type stars spend 10% of their entire main-sequence lives in periods of precipitously low activity, which is consistent with estimates from older field stars. As related asides, we note six evolved stars (among our UMa nonmembers) with distinctive kinematics that lie along a 2 Gyr isochrone and appear to be late-type counterparts to disk F stars defining intermediate-age star streams in previous studies, identify a small number of potentially very young but isolated field stars, note that active stars (whether UMa members or not) in our sample lie very close to the solar composition zero-age main sequence, unlike Hipparcos-based positions in the H-R diagram of Pleiades dwarfs, and argue that some extant transformations of activity indices are not adequate for cool dwarfs, for which Ca II infrared triplet emission seems to be a better proxy than Hα-based values for Ca II H and K indices.

Motion of an elastic capsule in a square microfluidic channel.

PubMed

Kuriakose, S; Dimitrakopoulos, P

2011-07-01

In the present study we investigate computationally the steady-state motion of an elastic capsule along the centerline of a square microfluidic channel and compare it with that in a cylindrical tube. In particular, we consider a slightly over-inflated elastic capsule made of a strain-hardening membrane with comparable shearing and area-dilatation resistance. Under the conditions studied in this paper (i.e., small, moderate, and large capsules at low and moderate flow rates), the capsule motion in a square channel is similar to and thus governed by the same scaling laws with the capsule motion in a cylindrical tube, even though in the channel the cross section in the upstream portion of large capsules is nonaxisymmetric (i.e., square-like with rounded corners). When the hydrodynamic forces on the membrane increase, the capsule develops a pointed downstream edge and a flattened rear (possibly with a negative curvature) so that the restoring tension forces are increased as also happens with droplets. Membrane tensions increase significantly with the capsule size while the area near the downstream tip is the most probable to rupture when a capsule flows in a microchannel. Because the membrane tensions increase with the interfacial deformation, a suitable Landau-Levich-Derjaguin-Bretherton analysis reveals that the lubrication film thickness h for large capsules depends on both the capillary number Ca and the capsule size a; our computations determine the latter dependence to be (in dimensionless form) h ~ a(-2) for the large capsules studied in this work. For small and moderate capsule sizes a, the capsule velocity Ux and additional pressure drop ΔP+ are governed by the same scaling laws as for high-viscosity droplets. The velocity and additional pressure drop of large thick capsules also follow the dynamics of high-viscosity droplets, and are affected by the lubrication film thickness. The motion of our large thick capsules is characterized by a Ux-U ~ h ~ a(-2) approach to the undisturbed average duct velocity and an additional pressure drop ΔP+ ~a(3)/h ~ a(5). By combining basic physical principles and geometric properties, we develop a theoretical analysis that explains the power laws we found for large capsules.

Protoplanetary Disks in Multiple Star Systems

NASA Astrophysics Data System (ADS)

Harris, Robert J.

Most stars are born in multiple systems, so the presence of a stellar companion may commonly influence planet formation. Theory indicates that companions may inhibit planet formation in two ways. First, dynamical interactions can tidally truncate circumstellar disks. Truncation reduces disk lifetimes and masses, leaving less time and material for planet formation. Second, these interactions might reduce grain-coagulation efficiency, slowing planet formation in its earliest stages. I present three observational studies investigating these issues. First is a spatially resolved Submillimeter Array (SMA) census of disks in young multiple systems in the Taurus-Auriga star-forming region to study their bulk properties. With this survey, I confirmed that disk lifetimes are preferentially decreased in multiples: single stars have detectable millimeter-wave continuum emission twice as often as components of multiples. I also verified that millimeter luminosity (proportional to disk mass) declines with decreasing stellar separation. Furthermore, by measuring resolved-disk radii, I quantitatively tested tidal-truncation theories: results were mixed, with a few disks much larger than expected. I then switch focus to the grain-growth properties of disks in multiple star systems. By combining SMA, Combined Array for Research in Millimeter Astronomy (CARMA), and Jansky Very Large Array (VLA) observations of the circumbinary disk in the UZ Tau quadruple system, I detected radial variations in the grain-size distribution: large particles preferentially inhabit the inner disk. Detections of these theoretically predicted variations have been rare. I related this to models of grain coagulation in gas disks and find that our results are consistent with growth limited by radial drift. I then present a study of grain growth in the disks of the AS 205 and UX Tau multiple systems. By combining SMA, Atacama Large Millimeter/submillimeter Array (ALMA), and VLA observations, I detected radial variations of the grain-size distribution in the AS 205 A disk, but not in the UX Tau A disk. I find that some combination of radial drift and fragmentation limits growth in the AS 205 A disk. In the final chapter, I summarize my findings that, while multiplicity clearly influences bulk disk properties, it does not obviously inhibit grain growth. Other investigations are suggested.

Assesment of access to bibliographic databases and telemetry databases in Astronomy: A groundswell for development.

NASA Astrophysics Data System (ADS)

Diaz-Merced, Wanda Liz; Casado, Johanna; Garcia, Beatriz; Aarnio, Alicia; Knierman, Karen; Monkiewicz, Jacqueline; Alicia Aarnio.

2018-01-01

Big Data" is a subject that has taken special relevance today, particularly in Astrophysics, where continuous advances in technology are leading to ever larger data sets. A multimodal approach in perception of astronomical data data (achieved through sonification used for the processing of data) increases the detection of signals in very low signal-to-noise ratio limits and is of special importance to achieve greater inclusion in the field of Astronomy. In the last ten years, different software tools have been developed that perform the sonification of astronomical data from tables or databases, among them the best known and in multiplatform development are Sonification Sandbox, MathTrack, and xSonify.In order to determine the accessibility of software we propose to start carrying out a conformity analysis of ISO (International Standard Organization) 9241-171171: 2008. This standard establishes the general guidelines that must be taken into account for accessibility in software design, and it is applied to software used in work, public places, and at home. To analyze the accessibility of web databases, we take into account the "Web Content Content Accessibility Guidelines (WCAG) 2.0", accepted and published by ISO in the ISO / IEC 40500: 2012 standard.In this poster, we present a User Centered Design (UCD), Human Computer Interaction (HCI), and User Experience (UX) framework to address a non-segregational provision of access to bibliographic databases and telemetry databases in Astronomy. Our framework is based on an ISO evaluation on a selection of data bases such as ADS, Simbad and SDSS. The WCAG 2.0 and ISO 9241-171171: 2008 should not be taken as absolute accessibility standards: these guidelines are very general, are not absolute, and do not address particularities. They are not to be taken as a substitute for UCD, HCI, UX design and evaluation. Based on our results, this research presents the framework for a focus group and qualitative data analysis aimed to lay the foundations for the employment of UCD functionalities on astronomical databases.

Feedback traps for virtual potentials

NASA Astrophysics Data System (ADS)

Gavrilov, Momčilo; Bechhoefer, John

2017-03-01

Feedback traps are tools for trapping and manipulating single charged objects, such as molecules in solution. An alternative to optical tweezers and other single-molecule techniques, they use feedback to counteract the Brownian motion of a molecule of interest. The trap first acquires information about a molecule's position and then applies an electric feedback force to move the molecule. Since electric forces are stronger than optical forces at small scales, feedback traps are the best way to trap single molecules without `touching' them (e.g. by putting them in a small box or attaching them to a tether). Feedback traps can do more than trap molecules: they can also subject a target object to forces that are calculated to be the gradient of a desired potential function U(x). If the feedback loop is fast enough, it creates a virtual potential whose dynamics will be very close to those of a particle in an actual potential U(x). But because the dynamics are entirely a result of the feedback loop-absent the feedback, there is only an object diffusing in a fluid-we are free to specify and then manipulate in time an arbitrary potential U(x,t). Here, we review recent applications of feedback traps to studies on the fundamental connections between information and thermodynamics, a topic where feedback plays an even more fundamental role. We discuss how recursive maximum-likelihood techniques allow continuous calibration, to compensate for drifts in experiments that last for days. We consider ways to estimate work and heat, using them to measure fluctuating energies to a precision of ±0.03 kT over these long experiments. Finally, we compare work and heat measurements of the costs of information erasure, the Landauer limit of kT ln 2 per bit of information erased. We argue that, when you want to know the average heat transferred to a bath in a long protocol, you should measure instead the average work and then infer the heat using the first law of thermodynamics. This article is part of the themed issue 'Horizons of cybernetical physics'.

Theoretical spectroscopy study of the low-lying electronic states of UX and UX{sup +}, X = F and Cl

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

Bross, David H.; Peterson, Kirk A., E-mail: kipeters@wsu.edu

Spectroscopic constants (T{sub e}, r{sub e}, B{sub 0}, ω{sub e}, and ω{sub e}x{sub e}) have been calculated for the low-lying electronic states of UF, UF{sup +}, UCl, and UCl{sup +} using complete active space 2nd-order perturbation theory (CASPT2), with a series of correlation consistent basis sets. The latter included those based on both pseudopotential (PP) and all-electron Douglas-Kroll-Hess Hamiltonians for the U atom. Spin orbit (SO) effects were included a posteriori using the state interacting method using both PP and Breit Pauli (BP) operators, as well as from exact two-component methods for U{sup +} and UF{sup +}. Complete basis setmore » (CBS) limits were obtained by extrapolation where possible and the PP and BP calculations were compared at their respective CBS limits. The PP-based method was shown to be reliable in calculating spectroscopic constants, in particular when using the state interacting method with CASPT2 energies (SO-CASPT2). The two component calculations were limited by computational resources and could not include electron correlation from the nominally closed shell 6s and 6p orbitals of U. UF and UCl were both calculated to have Ω = 9/2 ground states. The first excited state of UCl was calculated to be an Ω = 7/2 state at 78 cm{sup −1} as opposed to the same state at 435 cm{sup −1} in UF, and the other low-lying states of UCl showed a similar compression relative to UF. Likewise, UF{sup +} and UCl{sup +} both have Ω = 4 ground states and the manifold of low-lying excited Ω = 3, 2, 1, 0 states was energetically closer together in UCl{sup +} than in UF{sup +}, ranging up to 776 cm{sup −1} in UF{sup +} and only 438 cm{sup −1} in UCl{sup +}. As in previous studies, the final PP-based SO-CASPT2 results for UF{sup +} and UF agree well with experiment and are expected to be predictive for UCl and UCl{sup +}, which are reported here for the first time.« less

Theoretical spectroscopy study of the low-lying electronic states of UX and UX +, X = F and Cl

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

Bross, David H.; Peterson, Kirk A.

Spectroscopic constants (T e, r e, B 0, ω e, ω ex e) have been calculated for the low-lying electronic states of UF, UF +, UCl, and UCl + using complete active space 2nd-order perturbation theory (CASPT2), with a series of correlation consistent basis sets. The latter included those based on both pseudopotential (PP) and all-electron Douglas-Kroll-Hess (DK) Hamiltonians for the U atom. Spin orbit effects were included a posteri using the state interacting method using both PP and Breit Pauli (BP) operators, as well as from exact two-component (X2C) methods for U + and UF +. Complete basis setmore » (CBS) limits were obtained by extrapolation where possible and the PP and BP calculations were compared at their respective CBS limits. The PP-based method was shown to be reliable in calculating spectroscopic constants, in particular when using the state interacting method with CASPT2 energies (SO-CASPT2). The two component calculations were limited by computational resources and could not include electron correlation from the nominally closed shell 6s and 6p orbitals of U. UF and UCl were both calculated to have Ω=9/2 ground states. The first excited state of UCl was calculated to be an Ω=7/2 state at 78 cm -1 as opposed to the same state at 435 cm-1 in UF, and the other low-lying states of UCl showed a similar compression relative to UF. Likewise UF+ and UCl+ both have Ω=4 ground states and the manifold of low-lying excited Ω = 3, 2, 1, 0 states were energetically closer together in UCl + than in UF +, ranging up to 776 cm -1 in UF + and only 438 cm -1 in UCl +. As in previous research, the final PP-based SO-CASPT2 results for UF + and UF agree well with experiment, and are expected to be predictive for UCl and UCl +, which are reported here for the first time.« less

Theoretical spectroscopy study of the low-lying electronic states of UX and UX +, X = F and Cl

DOE PAGES

Bross, David H.; Peterson, Kirk A.

2015-11-13

Spectroscopic constants (T e, r e, B 0, ω e, ω ex e) have been calculated for the low-lying electronic states of UF, UF +, UCl, and UCl + using complete active space 2nd-order perturbation theory (CASPT2), with a series of correlation consistent basis sets. The latter included those based on both pseudopotential (PP) and all-electron Douglas-Kroll-Hess (DK) Hamiltonians for the U atom. Spin orbit effects were included a posteri using the state interacting method using both PP and Breit Pauli (BP) operators, as well as from exact two-component (X2C) methods for U + and UF +. Complete basis setmore » (CBS) limits were obtained by extrapolation where possible and the PP and BP calculations were compared at their respective CBS limits. The PP-based method was shown to be reliable in calculating spectroscopic constants, in particular when using the state interacting method with CASPT2 energies (SO-CASPT2). The two component calculations were limited by computational resources and could not include electron correlation from the nominally closed shell 6s and 6p orbitals of U. UF and UCl were both calculated to have Ω=9/2 ground states. The first excited state of UCl was calculated to be an Ω=7/2 state at 78 cm -1 as opposed to the same state at 435 cm-1 in UF, and the other low-lying states of UCl showed a similar compression relative to UF. Likewise UF+ and UCl+ both have Ω=4 ground states and the manifold of low-lying excited Ω = 3, 2, 1, 0 states were energetically closer together in UCl + than in UF +, ranging up to 776 cm -1 in UF + and only 438 cm -1 in UCl +. As in previous research, the final PP-based SO-CASPT2 results for UF + and UF agree well with experiment, and are expected to be predictive for UCl and UCl +, which are reported here for the first time.« less

Neutrino Factory Targets and the MICE Beam

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

Walaron, Kenneth Andrew

2007-01-01

The future of particle physics in the next 30 years must include detailed study of neutrinos. The first proof of physics beyond the Standard Model of particle physics is evident in results from recent neutrino experiments which imply that neutrinos have mass and flavour mixing. The Neutrino Factory is the leading contender to measure precisely the neutrino mixing parameters to probe beyond the Standard Model physics. Significantly, one must look to measure the mixing angle θ 13 and investigate the possibility of leptonic CP violation. If found this may provide a key insight into the origins of the matter/anti- mattermore » asymmetry seen in the universe, through the mechanism of leptogenesis. The Neutrino Factory will be a large international multi-billion dollar experiment combining novel new accelerator and long-baseline detector technology. Arguably the most important and costly features of this facility are the proton driver and cooling channel. This thesis will present simulation work focused on determining the optimal proton driver energy to maximise pion production and also simulation of the transport of this pion °ux through some candidate transport lattices. Bench-marking of pion cross- sections calculated by MARS and GEANT4 codes to measured data from the HARP experiment is also presented. The cooling channel aims to reduce the phase-space volume of the decayed muon beam to a level that can be e±ciently injected into the accelerator system. The Muon Ionisation Cooling Experiment (MICE) hosted by the Rutherford Appleton laboratory, UK is a proof-of-principle experiment aimed at measuring ionisation cooling. The experiment will run parasitically to the ISIS accelerator and will produce muons from pion decay. The MICE beamline provides muon beams of variable emittance and momentum to the MICE experiment to enable measurement of cooling over a wide range of beam conditions. Simulation work in the design of this beamline is presented in this thesis as are results from an experiment to estimate the °ux from the target into the beamline acceptance.« less

DET/MPS - THE GSFC ENERGY BALANCE PROGRAM, DIRECT ENERGY TRANSFER/MULTIMISSION SPACECRAFT MODULAR POWER SYSTEM (MACINTOSH A/UX VERSION)

NASA Technical Reports Server (NTRS)

Jagielski, J. M.

1994-01-01

The DET/MPS programs model and simulate the Direct Energy Transfer and Multimission Spacecraft Modular Power System in order to aid both in design and in analysis of orbital energy balance. Typically, the DET power system has the solar array directly to the spacecraft bus, and the central building block of MPS is the Standard Power Regulator Unit. DET/MPS allows a minute-by-minute simulation of the power system's performance as it responds to various orbital parameters, focusing its output on solar array output and battery characteristics. While this package is limited in terms of orbital mechanics, it is sufficient to calculate eclipse and solar array data for circular or non-circular orbits. DET/MPS can be adjusted to run one or sequential orbits up to about one week, simulated time. These programs have been used on a variety of Goddard Space Flight Center spacecraft projects. DET/MPS is written in FORTRAN 77 with some VAX-type extensions. Any FORTRAN 77 compiler that includes VAX extensions should be able to compile and run the program with little or no modifications. The compiler must at least support free-form (or tab-delineated) source format and 'do do-while end-do' control structures. DET/MPS is available for three platforms: GSC-13374, for DEC VAX series computers running VMS, is available in DEC VAX Backup format on a 9-track 1600 BPI tape (standard distribution) or TK50 tape cartridge; GSC-13443, for UNIX-based computers, is available on a .25 inch streaming magnetic tape cartridge in UNIX tar format; and GSC-13444, for Macintosh computers running AU/X with either the NKR FORTRAN or AbSoft MacFORTRAN II compilers, is available on a 3.5 inch 800K Macintosh format diskette. Source code and test data are supplied. The UNIX version of DET requires 90K of main memory for execution. DET/MPS was developed in 1990. A/UX and Macintosh are registered trademarks of Apple Computer, Inc. VMS, DEC VAX and TK50 are trademarks of Digital Equipment Corporation. UNIX is a registered trademark of AT&T Bell Laboratories.

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

Goldstein, A.; Veres, P.; Burns, E.

We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger (BBH) event GW170104. No candidate electromagnetic counterparts was detected by either GBM or LAT. A detailed analysis of the GBM and LAT data over timescales from seconds to days covering the LIGO localization region is presented. The resulting ux upper bound from the GBM is (5.2{9.4) 10 -7 erg cm -2 s -1 in the 10-1000 keV range and from the LAT is (0.2{13) 10 -9 erg cm -2 s -1 in the 0.1{1 GeV range. We also describemore » the improvements to our automated pipelines and analysis techniques for searching for and characterizing the potential electromagnetic counterparts for future gravitational wave events from Advanced LIGO/VIRGO.« less

Muon-Neutrino Electron Elastic Scattering and a Search for the Muon-Neutrino Magnetic Moment in the NOvA Near Detector

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

Wang, Biao

We use the NOvA near detector and the NuMI beam at Fermilab to study the neutrino- electron elastic scattering and the muon neutrino magnetic process beyond the Standard Model physics. The particle identications of neutrino on electron elastic scattering are trained by using the multi-layer neural networks. This thesis provides a general discussion of this technique and shows a good agreement between data and MC for the neutrino-electron elastic weak scattering. So that beneting from the precise cross-section of this channel, we are able to tune the neutrino beam ux simulation in the future. Giving the exposure of 3:62 1020more » POT in the NOvA near detector, we report 1:58 10« less

The Effect of Brand on the Evaluation of Websites

NASA Astrophysics Data System (ADS)

de Angeli, Antonella; Hartmann, Jan; Sutcliffe, Alistair

The effect of brand on consumer attitudes towards real and virtual goods is largely documented in consumer psychology and marketing. There is an obvious link between the design of a website and its brand. Yet, this effect has attracted little attention from the HCI community. This paper presents empirical evidence showing that brand attitude influences the evaluation of websites. The effect was reliable across different measures: people holding better attitudes were more positive in the evaluation of aesthetics, pleasure and usability. A sample of students (N=145) with a background in HCI was tested, suggesting that brand may influence the output of expert evaluators. The study provides support to the proposition of UX as a contextual-dependent response to the interaction with computing systems and has important implications for the design and evaluation of websites which are discussed in the conclusion.

Very long baseline interferometric observations of the hydroxyl masers in VY Canis Majoris

NASA Technical Reports Server (NTRS)

Reid, M. J.; Muhleman, D. O.

1978-01-01

Results are presented for spectral-line VLBI observations of the OH emission from VY CMa. The main-line (1665 and 1667 MHz) emission was mapped with an angular resolution of 0.02 arcsec by analyzing interferometer phase data. The main-line emission comes from many maser components of apparent size less than 0.03 arcsec which are separated by up to 0.5 arcsec. New maser features near the center of the OH spectra were detected and found to lie within the region encompassed by the low-velocity OH emission. The 1612-MHz emission was mapped by Fourier inversion of the VLBI data from two baselines. All spatially isolated maser components appeared smaller than 0.15 arcsec; however, the maser emission is very complex at most velocities. Maser components within a velocity range of 1.3 km/s are often separated by more than 1 arcsec, while components more than 10 km/s apart in each emission complex are often coincident to 0.2 arcsec.

The Publicly Available Prebiotic Interstellar Molecular Survey (primos): Expanding Spectroscopic Characterizations, Extending to New Sources, and Adding to the Known Molecular Inventory

NASA Astrophysics Data System (ADS)

McGuire, Brett A.; Carroll, P. Brandon; Corby, Joanna F.; Loomis, Ryan A.; Blake, Geoffrey A.; Hollis, Jan M.; Lovas, Frank J.; Jewell, Philip R.; Remijan, Anthony J.

2013-06-01

The publicly available Green Bank Telescope PRebiotic Interstellar MOlecular Survey (PRIMOS) conducted towards Sgr B2(N) provides high resolution, high-sensitivity observations with near-continuous frequency coverage from ˜300 MHz - 50 GHz. Of the eleven new molecular detections in the last year, five (45%) are a direct result of the PRIMOS observations. Further, these observations have recently been used to detect the predicted, but previously unobserved, J = 1-0 and J=2-1 transitions of the newly detected l-C_3H^+ ion. Here, we discuss the analysis of these transitions, as well as recent work to extend the PRIMOS observations to three new regions of interest: VY Canis Majoris, IRC+10216, and NGC 2023. Finally, we highlight the utility of cm-wave surveys in new molecular detections, as well as the value of publicly-available surveys in the approaching era of data-enabled, analysis-limited astrochemistry.

The Aro 1 mm Survey of the Oxygen-Rich Envelope of Supergiant Star NML Cygnus

NASA Astrophysics Data System (ADS)

Edwards, Jessica L.; Ziurys, L. M.; Woolf, N. J.

2011-06-01

Although a number of molecular line surveys of carbon-rich circumstellar envelopes (CSE) have been performed, only one oxygen-rich CSE, that of VY Canis Majoris (VY CMa), has been studied in depth. The Arizona Radio Observatory (ARO) 1 mm survey of VY CMa showed a very different and interesting chemistry dominated by sulfur- and silicon-bearing compounds as well as a number of more exotic species. A similar survey of the oxygen rich star NML Cygnus (NML Cyg) from 215 to 285 GHz is currently under way using the ARO Sub-millimeter Telescope. Initial observations show that this circumstellar envelope appears to be as chemically rich as that of VY CMa. Molecules including 12CO, 13CO, 12CN, 13CN, HCN, HCO+, CS, SO{_2}, SiO and 30SiO have been observed in NML Cyg. Line profiles of this source also suggest that there may be multiple outflows and that the circumstellar envelope is not spherically symmetric. Current results will be presented.

An Interferometric 270--355 GHz Spectral Line Survey of the Red Supergiant VY CMa

NASA Astrophysics Data System (ADS)

Menten, K. M.; Young, K. H.; Patel, N. A.; Gottlieb, C. A.; Thaddeus, P.; McCarthy, M. C.; Gurwell, M. A.; Belloche, A.; Kaminski, T.; Verheyen, L.; Decin, L.; Brunken, S.; Holger, S. P. M.

2011-05-01

We have used the Submillimeter Array to image the molecular line emission in the circumstellar envelope of the peculiar red supergiant star VY Canis Majoris over the whole 870 μm atmospheric window. Employing adaptive calibration using the object's continuum emission we achieve high quality one arcsecond resolution imaging of the whole 280--355 GHz range within which we find 211 distinct spectral lines from 33 molecules (including isotopologues) plus 40 unidentified lines. From the distribution of molecules we are obtaining their abundances and isotopologic abundance ratios. Using data for multiple transitions in a number of molecules we are deriving the physical conditions in the circumstellar envelope to reach a picture of the star's chemistry that can be compared with models. Our legacy survey is accompanied by a strong laboratory effort that helps with the identification of possibly newly found molecules traced by unidentified lines. We shall create a publicly accessible database of spectral-line channel-maps of the emission from all the lines detected in the survey.

The quenching of the ultra-faint dwarf galaxies in the reionization era

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

Brown, Thomas M.; Tumlinson, Jason; Kalirai, Jason S.

2014-12-01

We present new constraints on the star formation histories of six ultra-faint dwarf galaxies: Bootes I, Canes Venatici II, Coma Berenices, Hercules, Leo IV, and Ursa Major I. Our analysis employs a combination of high-precision photometry obtained with the Advanced Camera for Surveys on the Hubble Space Telescope, medium-resolution spectroscopy obtained with the DEep Imaging Multi-Object Spectrograph on the W. M. Keck Observatory, and updated Victoria-Regina isochrones tailored to the abundance patterns appropriate for these galaxies. The data for five of these Milky Way satellites are best fit by a star formation history where at least 75% of the starsmore » formed by z ∼ 10 (13.3 Gyr ago). All of the galaxies are consistent with 80% of the stars forming by z ∼ 6 (12.8 Gyr ago) and 100% of the stars forming by z ∼ 3 (11.6 Gyr ago). The similarly ancient populations of these galaxies support the hypothesis that star formation in the smallest dark-matter sub-halos was suppressed by a global outside influence, such as the reionization of the universe.« less

THE PRIMEVAL POPULATIONS OF THE ULTRA-FAINT DWARF GALAXIES

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

Brown, Thomas M.; Tumlinson, Jason; Kalirai, Jason S.

We present new constraints on the star formation histories of the ultra-faint dwarf (UFD) galaxies, using deep photometry obtained with the Hubble Space Telescope (HST). A galaxy class recently discovered in the Sloan Digital Sky Survey, the UFDs appear to be an extension of the classical dwarf spheroidals to low luminosities, offering a new front in efforts to understand the missing satellite problem. They are the least luminous, most dark-matter-dominated, and least chemically evolved galaxies known. Our HST survey of six UFDs seeks to determine if these galaxies are true fossils from the early universe. We present here the preliminarymore » analysis of three UFD galaxies: Hercules, Leo IV, and Ursa Major I. Classical dwarf spheroidals of the Local Group exhibit extended star formation histories, but these three Milky Way satellites are at least as old as the ancient globular cluster M92, with no evidence for intermediate-age populations. Their ages also appear to be synchronized to within {approx}1 Gyr of each other, as might be expected if their star formation was truncated by a global event, such as reionization.« less

Absolute Properties of the Eclipsing Binary Star BF Draconis

NASA Astrophysics Data System (ADS)

Lacy, Claud H. Sandberg; Torres, Guillermo; Fekel, Francis C.; Sabby, Jeffrey A.; Claret, Antonio

2012-06-01

BF Dra is now known to be an eccentric double-lined F6+F6 binary star with relatively deep (0.7 mag) partial eclipses. Previous studies of the system are improved with 7494 differential photometric observations from the URSA WebScope and 9700 from the NFO WebScope, 106 high-resolution spectroscopic observations from the Tennessee State University 2 m automatic spectroscopic telescope and the 1 m coudé-feed spectrometer at Kitt Peak National Observatory, and 31 accurate radial velocities from the CfA. Very accurate (better than 0.6%) masses and radii are determined from analysis of the two new light curves and four radial velocity curves. Theoretical models match the absolute properties of the stars at an age of about 2.72 Gyr and [Fe/H] = -0.17, and tidal theory correctly confirms that the orbit should still be eccentric. Our observations of BF Dra constrain the convective core overshooting parameter to be larger than about 0.13 Hp . We find, however, that standard tidal theory is unable to match the observed slow rotation rates of the components' surface layers.

Detection of extrasolar planets by the large deployable reflector

NASA Technical Reports Server (NTRS)

Hollenbach, D. J.; Takahashi, T.

1984-01-01

The best wavelength for observing Jupiter-size planetary companions to stars other than the Sun is one at which a planet's thermal emission is strongest; typically this would occur in the far-infrared region. It is assumed that the orbiting infrared telescope used is diffraction-limited so that the resolution of the planet from the central star is accomplished in the wings of the star's Airy pattern. Proxima Centauri, Barnard's Star, Wolf 359, and Epsilon Eridani are just a few of the many nearest main-sequence stars that could be studied with the large deployable relfector (LDR). The detectability of a planet improves for warmer planets and less luminous stars; therefore, planets around white dwarfs and those young planets which have sufficient internal gravitational energy release so as to cause a significant increase in their temperatures are considered. If white dwarfs are as old as they are usually assumed to be (5-10 billion yr), then only the nearest white dwarf (Sirius B) is within the range of LDR. The Ursa Major cluster and Perseu cluster are within LDR's detection range mainly because of their proximity and young age, respectively.

Recent Results of the Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Ivanov, Dmitri

2015-04-01

The Telescope Array (TA) is the largest cosmic ray experiment in the northern hemisphere and covers 10 PeV to 100 EeV range. TA is a hybrid detector that uses air fluorescence detectors combined with a ground array. TA consists of 507 plastic scintillation counters on a 1.2km square grid, overlooked by 3 fluorescence detector stations, and measures cosmic rays above 1 EeV. TA has collected 6.5 years of data. Results from the TA low energy extension (TALE), which sees cosmic rays down to 10 PeV, will also be shown. This contribution will consist of three parts. First, we will present the cosmic ray energy spectrum measured over 4 decades in energy. Next, we will discuss the latest results of the measurements of cosmic ray mass composition by the TA fluorescence detectors. Finally, we will show the latest results of the TA anisotropy measurements at the highest energies, where we have seen a concentration of events, called the ``hotspot,'' centered in the Ursa Major. For the Telescope Array Collaboration. Done...processed 1261 records...10:46:59 Beginning APS data extraction...10:47:48

Recent results from the Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Abbasi, Rasha; Telescope Array Collaboration

2016-03-01

The Telescope Array (TA) is the largest ultrahigh energy cosmic rays detector in the northern hemisphere. TA is a hybrid detector comprised of three air fluorescence stations and a large surface array consisting of 507 scintillator counters. Each of the three fluorescence stations, located at the periphery of the ground array, views 108 degrees in azimuth and up to 30 degrees in elevation. The surface detectors are arranged in a square grid of 1.2 km spacing, covering over 700 square kilometers. TA has collected more than seven years of data. In this talk, we will present some of the main results on the cosmic rays composition and energy spectrum obtained by TA and its low energy extension (TALE). Finally, we will present our results from the search for arrival direction anisotropy, including the observed large excess of events at the highest energies, seen in the region of the northern sky centered on Ursa Major. Based on the current results, the ``hot spot'' in particular, TA is pursuing the expansion of the surface array to four times its current size.

The dwarf galaxy population of nearby galaxy clusters

NASA Astrophysics Data System (ADS)

Lisker, Thorsten; Wittmann, Carolin; Pak, Mina; Janz, Joachim; Bialas, Daniel; Peletier, Reynier; Grebel, Eva; Falcon Barroso, Jesus; Toloba, Elisa; Smakced Collaboration, Focus Collaboration

2015-01-01

The Fornax, Virgo, Ursa Major and Perseus galaxy clusters all have very different characteristics, in terms of their density, mass, and large-scale environment. We can regard these clusters as laboratories for studying environmental influence on galaxy evolution, using the sensitive low-mass galaxies as probes for external mechanisms. Here we report on recent and ongoing observational studies of the said clusters with imaging and spectroscopy, as well as on the interpretation of present-day cluster galaxy populations with the aid of cosmological simulations.Multicolor imaging data allow us to identify residual star formation in otherwise red early-type dwarf galaxies, which hold clues to the strength of gas stripping processes. Major-axis spectra and 2D kinematical maps provide insight regarding the amount of rotational support and how much dynamical heating a dwarf galaxy may have experienced. To this end, dedicated N-body simulations that follow the evolution of galaxies since early epochs reveal their path through parameter space, and can be compared to observations in order to understand the time-integrated effect of environmental influence.

Spectroscopic study on the iodine molecule by a sequential three-photon excitation

NASA Astrophysics Data System (ADS)

Ishiwata, Takashi; Ohtoshi, Hirokazu; Sakaki, Mamoru; Tanaka, Ikuzo

1984-02-01

A three-photon absorption technique which utilizes a visible B 3Π0+u-X 1Σ+g transition followed by a simultaneous two-photon absorption was applied to study an ion-pair state of molecular iodine. The derived molecular parameters were Te=51 707 cm-1, ωe=131 cm-1, and Be=0.021 90 cm-1 for the F'(0+u) ion-pair state, which dissociates to I-(1S)+I+(1D). The excitation of I2 to a single rovibronic level of the F' state was achieved and its fluorescence spectrum showed two discrete band systems corresponding to the transitions to: (1) the ground state at higher vibrational levels; and (2) the weakly bound state (Te=19 286 cm-1, ωe=64 cm-1, and re=3.65 Å) converging to the I(2P3/2)+I(2P1/2) products.

Lamp of adjustable spectrum for photographic usage

NASA Astrophysics Data System (ADS)

Mazikowski, Adam; Feldzensztajn, Mateusz

2017-08-01

Photography is a unique rapidly growing interdisciplinary field encompassing aspects of science, art and technology. Expectations of photographers are steadily increasing with the development of technology. One of the areas playing a crucial role in photography is lighting. Consequently, several types of light sources for photographic use have been developed. The ongoing research in this field concentrates on lamps with tunable CCT (Correlated Color Temperature). In this paper, we present a lamp, which emission spectrum can be tailored without affecting the output luminous ux. Intended for photographic uses, the lamp is based on an integrating sphere and a selection of LEDs. As the LED drivers, DC-DC converters controlled by a Raspberry PI were applied. Design process, including the selection of LED wavelengths, is presented. Output characteristics of the lamp were measured using the setup containing the spectrometer. The results of these experiments show good agreement with the spectrum set on the microcomputer.

Fermi Observations of the LIGO Event GW170104

DOE PAGES

Goldstein, A.; Veres, P.; Burns, E.; ...

2017-08-28

We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger (BBH) event GW170104. No candidate electromagnetic counterparts was detected by either GBM or LAT. A detailed analysis of the GBM and LAT data over timescales from seconds to days covering the LIGO localization region is presented. The resulting ux upper bound from the GBM is (5.2{9.4) 10 -7 erg cm -2 s -1 in the 10-1000 keV range and from the LAT is (0.2{13) 10 -9 erg cm -2 s -1 in the 0.1{1 GeV range. We also describemore » the improvements to our automated pipelines and analysis techniques for searching for and characterizing the potential electromagnetic counterparts for future gravitational wave events from Advanced LIGO/VIRGO.« less

The Rapidly Rotating Sun

NASA Technical Reports Server (NTRS)

Hanasoge, Shravan M.; Duvall, Thomas L., Jr.; Sreenivasan, Katepalli R.

2012-01-01

Convection in the solar interior is thought to comprise structures at a continuum of scales, from large to small. This conclusion emerges from phenomenological studies and numerical simulations though neither covers the proper range of dynamical parameters of solar convection. In the present work, imaging techniques of time-distance helioseismology applied to observational data reveal no long-range order in the convective motion. We conservatively bound the associated velocity magnitudes, as a function of depth and the spherical-harmonic degree l to be 20-100 times weaker than prevailing estimates within the wavenumber band l < 60. The observationally constrained kinetic energy is approximately a thousandth of the theoretical prediction, suggesting the prevalence of an intrinsically different paradigm of turbulence. A fundamental question arises: what mechanism of turbulence transports the heat ux of a solar luminosity outwards? The Sun is seemingly a much faster rotator than previously thought, with advection dominated by Coriolis forces at scales l < 60.

New Scattered Disk Object and Centaur Colors

NASA Astrophysics Data System (ADS)

Brucker, Melissa; Wilcox, P.; Stansberry, J.

2013-10-01

We report B, V, and R magnitudes for scattered disk objects and centaurs from observations taken in December 2011 and August 2013 using the Lowell Observatory Perkins Telescope with PRISM and observations taken in March 2012 at the Vatican Advanced Technology Telescope (VATT) on Mt. Graham, Arizona. Targeted scattered disk objects include 2002 CY224, 2003 UY117, 2006 QJ181, 2008 CT190, 2009 YG19, 2010 FD49, 2010 VZ98. Targeted centaurs include 2002 QX47, 2005 UJ438, 2006 UX184, and 2007 RH283. We will determine if the resultant centaur colors follow the bimodal distribution (B-R either red or gray) previously detected. We will also compare the resultant scattered disk object colors to those published for other scattered disk objects. This work is based on observations with the Perkins Telescope at Lowell Observatory, and with the VATT: The Alice P. Lennon Telescope and the Thomas J. Bannan Astrophysics Facility.

Predicting Scenarios for Successful Autodissemination of Pyriproxyfen by Malaria Vectors from Their Resting Sites to Aquatic Habitats; Description and Simulation Analysis of a Field-Parameterizable Model.

PubMed

Kiware, Samson S; Corliss, George; Merrill, Stephen; Lwetoijera, Dickson W; Devine, Gregor; Majambere, Silas; Killeen, Gerry F

2015-01-01

Large-cage experiments indicate pyriproxifen (PPF) can be transferred from resting sites to aquatic habitats by Anopheles arabiensis--malaria vector mosquitoes to inhibit emergence of their own offspring. PPF coverage is amplified twice: (1) partial coverage of resting sites with PPF contamination results in far higher contamination coverage of adult mosquitoes because they are mobile and use numerous resting sites per gonotrophic cycle, and (2) even greater contamination coverage of aquatic habitats results from accumulation of PPF from multiple oviposition events. Deterministic mathematical models are described that use only field-measurable input parameters and capture the biological processes that mediate PPF autodissemination. Recent successes in large cages can be rationalized, and the plausibility of success under full field conditions can be evaluated a priori. The model also defines measurable properties of PPF delivery prototypes that may be optimized under controlled experimental conditions to maximize chances of success in full field trials. The most obvious flaw in this model is the endogenous relationship that inevitably occurs between the larval habitat coverage and the measured rate of oviposition into those habitats if the target mosquito species is used to mediate PPF transfer. However, this inconsistency also illustrates the potential advantages of using a different, non-target mosquito species for contamination at selected resting sites that shares the same aquatic habitats as the primary target. For autodissemination interventions to eliminate malaria transmission or vector populations during the dry season window of opportunity will require comprehensive contamination of the most challenging subset of aquatic habitats [Formula: see text] that persist or retain PPF activity (Ux) for only one week [Formula: see text], where Ux = 7 days). To achieve >99% contamination coverage of these habitats will necessitate values for the product of the proportional coverage of the ovipositing mosquito population with PPF contamination (CM) by the ovitrap-detectable rates of oviposition by wild mosquitoes into this subset of habitats [Formula: see text], divided by the titre of contaminated mosquitoes required to render them unproductive [Formula: see text], that approximately approach unity [Formula: see text]. The simple multiplicative relationship between CM and [Formula: see text], and the simple exponential decay effect they have upon uncontaminated aquatic habitats, allows application of this model by theoreticians and field biologists alike.

A rotating, expanding disk in the Wolf-Rayet star EZ Canis Majoris?

NASA Technical Reports Server (NTRS)

Schulte-Ladbeck, R. E.; Nordsieck, K. H.; Nook, M. A.; Magalhaes, A. M.; Taylor, M.

1990-01-01

The discovery of linear polarization changes across the extended wings of He II lines, mainly the strong 4-3 transition at 4686 A, in the WN5 star EZ CMa, is reported. When the polarization across the line profiles is plotted in the Stokes parameters plane, it traces loops clockwise from the blue wing through line center to the red, rather than straight lines. Such polarization loops are reminiscent of what is observed in the Balmer lines of Be stars. The continuum polarization in EZ CMa can be understood by an axisymmetric, electron-scattering envelope, with the decrease in polarization in He II being caused by an increase in absorptive opacity in the lines and dilution by unpolarized line emission, while the variations in position angle are due to the Doppler-shifted absorptive opacity and/or scattered line photons. As the sense of rotation in the loops is also independent of phase of this alleged Wolf-Rayet + compact binary, the polarized line profiles are the signature of a rotating, expanding wind geometry around a single star.

Interferometric Studies of Red Giants with MAPPIT

NASA Astrophysics Data System (ADS)

Ireland, Michael J.

2002-06-01

Powerful new tools for the analysis of wavelength-dispersed aperture masking data are presented, as applied to the MAPPIT instrument of the 3.9 m Anglo-Australia Telescope. By using both baseline and wavelength bootstrapping simultaneously, solutions were found for the phase of wavefronts degraded by atmospheric and instrumental effects. This allowed coherent processing of many data sets, greatly improving signal-to-noise both at the longest baselines for well resolved objects, and at all baselines in for data in TiO absorption bands. Using this new techniques, as well as power spectrum-based techniques, wavelength-dependent diameters are found in the range 650-950 nm for the following stars: R Carinae, R Leonis, omicron Ceti, R Hydrae, W Hydrae, R Doradus, L2 Puppis, alpha Orionis, gamma Crucis, eta Carinae and VY Canis Majoris. All the Mira-like stars showed greater than 50% variation in diameter over the available wavelength range. L2 Puppis, a semi-regular variable resolved for the first time, showed a variation in diameter consistent with scattering by a recently ejected shell of dust.

A Millimeter Polarimeter for the 45-m Telescope at Nobeyama

NASA Astrophysics Data System (ADS)

Shinnaga, Hiroko; Tsuboi, Masato; Kasuga, Takashi

1999-04-01

We have designed and constructed a tunable polarimeter to cover frequencies from 35 GHz to 250 GHz (8.6 mm and 1.2 mm in wavelength) for the 45-m telescope at Nobeyama Radio Observatory. Both circular and linear polarizations can be measured by the polarimeter. The insertion loss was measured to be 0.14 +/- 0.05 dB in the 100-GHz band. The overall instrumental polarization of the system in the 100 GHz band is as low as <= 3%. The performance of the polarimeter in astronomical observations was tested by simultaneously measuring the linear polarization of the J = 2--1 transition of SiO in the v = 0 and 1 states at 86 GHz toward VY Canis Majoris. The observation revealed that the J = 2--1 emission in the v = 0 state of the object is highly linear polarized, which suggests that the emission originates through maser action in the circumstellar region. The details of the design, construction, and tests are presented. Nobeyama Radio Observatory is a branch of the National Astronomical Observatory, operated by the Ministry of Education, Science, Sports and Culture.

Mid-Infrared Interferometry on Spectral Lines. II. Continuum (Dust) Emission Around IRC +10216 and VY Canis Majoris

NASA Astrophysics Data System (ADS)

Monnier, J. D.; Danchi, W. C.; Hale, D. S.; Lipman, E. A.; Tuthill, P. G.; Townes, C. H.

2000-11-01

The University of California Berkeley Infrared Spatial Interferometer has measured the mid-infrared visibilities of the carbon star IRC +10216 and the red supergiant VY CMa. The dust shells around these sources have been previously shown to be time variable, and these new data are used to probe the evolution of the dust shells on a decade timescale, complementing contemporaneous studies at other wavelengths. Self-consistent, spherically symmetric models at maximum and minimum light both show the inner radius of the IRC +10216 dust shell to be much larger (150 mas) than expected from the dust-condensation temperature, implying that dust production has slowed or stopped in recent years. Apparently, dust does not form every pulsational cycle (638 days), and these mid-infrared results are consistent with recent near-infrared imaging, which indicates little or no new dust production in the last 3 yr. Spherically symmetric models failed to fit recent VY CMa data, implying that emission from the inner dust shell is highly asymmetric and/or time variable.

First mm-VLBI Observations between the TRAO 14-m and the NRO 45-m Telescopes: Observations of 86 GHz SiO Masers in VY Canis Majoris

NASA Astrophysics Data System (ADS)

Shibata, Katsunori M.; Chung, Hyung-Soo; Kameno, Seiji; Roh, Duk-Gyoo; Umemoto, Tomofumi; Kim, Kwang-Dong; Asada, Keiichi; Han, Seog-Tae; Mochizuki, Nanako; Cho, Se-Hyung; Sawada-Satoh, Satoko; Kim, Hyun-Goo; Bushimata, Takeshi; Minh, Young Chol; Miyaji, Takeshi; Kuno, Nario; Mikoshiba, Hiroshi; Sunada, Kazuyoshi; Inoue, Makoto; Kobayashi, Hideyuki

2004-06-01

We have made VLBI observations at 86GHz using a 1000-km baseline between Korea and Japan with successful detections of SiO v = 1, J = 2 - 1 maser emissions from VY CMa and Orion KL in 2001 June. This was the first VLBI result for this baseline and the first astronomical VLBI observation for the Korean telescope. Since then, we observed SiO v = 1, J = 2 - 1 maser emission in VY CMa in 2002 January and 2003 February and derived the distributions of the maser emissions. Our results show that the maser emissions extend over 2-4 stellar radii, and were within the inner radius of the dust shell. We observed other SiO maser sources and continuum sources, and 86-GHz continuum emissions were detected from three continuum sources. It was verified that this baseline has a performance comparable to the most sensitive baseline in the VLBA and the CMVA, and is capable of investigating the proper motions of maser features in circumstellar envelopes using monitoring observations.

Simultaneous IUE and Ground Based Observations of SS Cygni and HL Canis Majoris

NASA Astrophysics Data System (ADS)

Mansperger, C. S.; Kaitchuck, R. H.; Garnavich, P.; Dinshaw, N.

1993-05-01

SS Cyg and HL CMa were observed by IUE for three consecutive nights in November of 1992. During the first two nights, simultaneous photometric ground based observations of SS Cyg were made at the Ball State University Observatory. SS Cyg and HL CMa were observed simultaneously with the 90-inch telescope at the Steward Observatory on the last two nights of this run. These spectroscopic observations covered the wavelength range of 4100 Angstroms to 5000 Angstroms, while the spectra taken with the short wavelength camera on IUE resulted in wavelength coverage from 1150 Angstroms to 1980 Angstroms. SS Cyg is a U Gem type dwarf nova with an orbital period of 6.6 hours. Good simultaneous UV and optical orbital coverage was obtained for this system. HL CMa is a Z Cam type dwarf nova with an outburst period of 18 days. The AAVSO reports that this system was in outburst 4 days after the observing run. Therefore, HL CMa may have been in a preoutburst state during these observations. The C IV and H \\beta emission lines appeared to have weakened during this time.

Inferring the Diets of Extinct Giant Lemurs from Osteological Correlates of Muscle Dimensions.

PubMed

Perry, Jonathan M G

2018-02-01

The jaw adductor muscles of extinct mammals are often reconstructed to elucidate paleoecological relationships and to make broad comparisons among taxa. Muscle lever arms, bite load arms, muscle dimensions, and gape are often also reconstructed to better understand feeding. Several different approaches to these and related goals are discussed here. A protocol for reconstructing muscle dimensions and bite force using biomechanically informative skull measurements and osteological proxies of muscle dimensions is described and applied to a case study of subfossil Malagasy lemurs. The results of this case study show that most subfossil lemurs emphasized the masseter and medial pterygoid muscles over the temporalis. This supports the inference that these extinct lemurs depended heavily on tough food like leaves. Exceptions include signals of hard-object feeding in Archaeolemur that vary between A. majori and A. edwardsi. Reconstructions of soft-tissue and function are important for understanding past ecological relationships. Even those based on well-supported osteological proxies from extant analogues have limitations for making precise inferences. Anat Rec, 301:343-362, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Moduli Dark Matter and the Search for Its Decay Line using Suzaku X-Ray Telescope

NASA Technical Reports Server (NTRS)

Kusenko, Alexander; Loewenstein, Michael; Yanagida, Tsutomu T.

2013-01-01

Light scalar fields called moduli arise from a variety of different models involving supersymmetry and/or string theory; thus their existence is a generic prediction of leading theories for physics beyond the standard model. They also present a formidable, long-standing problem for cosmology. We argue that an anthropic solution to the moduli problem exists in the case of small moduli masses and that it automatically leads to dark matter in the form of moduli. The recent discovery of the 125 GeV Higgs boson implies a lower bound on the moduli mass of about a keV. This form of dark matter is consistent with the observed properties of structure formation, and it is amenable to detection with the help of x-ray telescopes. We present the results of a search for such dark matter particles using spectra extracted from the first deep x-ray observations of the Draco and Ursa Minor dwarf spheroidal galaxies, which are darkmatter- dominated systems with extreme mass-to-light ratios and low intrinsic backgrounds. No emission line is positively detected, and we set new constraints on the relevant new physics.

Identifying Type Ia Supernova Mechanisms in Dwarf Spheroidal Galaxies through Analysis of Iron-peak Elemental Abundances

NASA Astrophysics Data System (ADS)

Guo, Rachel; Xie, Justin Long; Kirby, Evan N.

2017-01-01

Through the fusion of nucleons to produce elements heavier than hydrogen and helium, stellar nucleosynthesis produces most of the elements in the universe. Such is the case in a supernova explosion, which creates most of the elements on the periodic table—including iron-peak elements, atomic numbers 21 through 30—through nucleosynthesis and ejects them into the interstellar medium. In this study, we determine the best theoretical supernova model appropriate for the stars in the dwarf spheroidal galaxies Sculptor, Fornax, Ursa Minor, and Leo II by calculating the abundances of iron-peak elements in these stars. To determine iron-peak elemental abundances, we compare synthesized spectra with observed spectra from medium-resolution spectroscopy and determine the best-fitting spectrum by way of a chi-squared minimization. Through inspecting the relationship between the iron-peak element abundances and the abundance of iron itself and by comparing them to previously hypothesized supernova model theories, we discover that the near-Chandrasekhar mass “n1” model, as predicted by Seitenzahl et al., most accurately represents the trends and patterns within our data, presenting new insight into Type Ia supernovae mechanisms within the Milky Way and beyond.

STAR FORMATION IN ULTRA-FAINT DWARFS: CONTINUOUS OR SINGLE-AGE BURSTS?

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

Webster, David; Bland-Hawthorn, Joss; Sutherland, Ralph, E-mail: d.webster@physics.usyd.edu.au

2015-01-30

We model the chemical evolution of six ultra-faint dwarfs (UFDs): Bootes I, Canes Venatici II, Coma Berenices, Hercules, Leo IV, and Ursa Major I based on their recently determined star formation histories. We show that two single-age bursts cannot explain the observed [α/Fe] versus [Fe/H] distribution in these galaxies and that some self-enrichment is required within the first burst. An alternative scenario is modeled, in which star formation is continuous except for short interruptions when one or more supernovae temporarily blow the dense gas out from the center of the system. This model allows for self-enrichment and can reproduce themore » chemical abundances of the UFDs in which the second burst is only a trace population. We conclude that the most likely star formation history is one or two extended periods of star formation, with the first burst lasting for at least 100 Myr. As found in earlier work, the observed properties of UFDs can be explained by formation at a low mass (M{sub vir}∼10{sup 7} M{sub ⊙}), rather than being stripped remnants of much larger systems.« less

HUBBLE FINDS A BARE BLACK HOLE POURING OUT LIGHT

NASA Technical Reports Server (NTRS)

2002-01-01

NASA's Hubble Space Telescope has provided a never-before-seen view of a warped disk flooded with a torrent of ultraviolet light from hot gas trapped around a suspected massive black hole. [Right] This composite image of the core of the galaxy was constructed by combining a visible light image taken with Hubble's Wide Field Planetary Camera 2 (WFPC2), with a separate image taken in ultraviolet light with the Faint Object Camera (FOC). While the visible light image shows a dark dust disk, the ultraviolet image (color-coded blue) shows a bright feature along one side of the disk. Because Hubble sees ultraviolet light reflected from only one side of the disk, astronomers conclude the disk must be warped like the brim of a hat. The bright white spot at the image's center is light from the vicinity of the black hole which is illuminating the disk. [Left] A ground-based telescopic view of the core of the elliptical galaxy NGC 6251. The inset box shows Hubble Space Telescope's field of view. The galaxy is 300 million light-years away in the constellation Ursa Minor. Photo Credit: Philippe Crane (European Southern Observatory), and NASA

Hubble Peers Through the Elliptical Haze

NASA Image and Video Library

2017-12-08

Like a lighthouse in the fog, the luminous core of NGC 2768 slowly fades outwards to a dull white haze in this image taken by the NASA/ESA Hubble Space Telescope. NGC 2768 is an elliptical galaxy in the constellation of Ursa Major (The Great Bear). It is a huge bundle of stars, dominated by a bright central region, where a supermassive black hole feasts on a constant stream of gas and dust being fed to it by its galactic host. The galaxy is also marked by a prominent plume of dust reaching out from the center and lying perpendicular to the galaxy’s plane. This dust conceals a symmetrical, S-shaped pair of jets that are being produced by the supermassive black hole as it feeds. Credit: ESA/Hubble, NASA and S. Smartt (Queen's University Belfast) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The Little Cub: Discovery of an Extremely Metal-poor Star-forming Galaxy in the Local Universe

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

Hsyu, Tiffany; Prochaska, J. Xavier; Bolte, Michael

We report the discovery of the Little Cub, an extremely metal-poor star-forming galaxy in the local universe, found in the constellation Ursa Major (a.k.a. the Great Bear). We first identified the Little Cub as a candidate metal-poor galaxy based on its Sloan Digital Sky Survey photometric colors, combined with spectroscopy using the Kast spectrograph on the Shane 3 m telescope at Lick Observatory. In this Letter, we present high-quality spectroscopic data taken with the Low Resolution Imaging Spectrometer at Keck Observatory, which confirm the extremely metal-poor nature of this galaxy. Based on the weak [O iii] λ 4363 Å emissionmore » line, we estimate a direct oxygen abundance of 12 + log(O/H) = 7.13 ± 0.08, making the Little Cub one of the lowest-metallicity star-forming galaxies currently known in the local universe. The Little Cub appears to be a companion of the spiral galaxy NGC 3359 and shows evidence of gas stripping. We may therefore be witnessing the quenching of a near-pristine galaxy as it makes its first passage about a Milky Way–like galaxy.« less

Early gas stripping as the origin of the darkest galaxies in the Universe.

PubMed

Mayer, L; Kazantzidis, S; Mastropietro, C; Wadsley, J

2007-02-15

The known galaxies most dominated by dark matter (Draco, Ursa Minor and Andromeda IX) are satellites of the Milky Way and the Andromeda galaxies. They are members of a class of faint galaxies, devoid of gas, known as dwarf spheroidals, and have by far the highest ratio of dark to luminous matter. None of the models proposed to unravel their origin can simultaneously explain their exceptional dark matter content and their proximity to a much larger galaxy. Here we report simulations showing that the progenitors of these galaxies were probably gas-dominated dwarf galaxies that became satellites of a larger galaxy earlier than the other dwarf spheroidals. We find that a combination of tidal shocks and ram pressure swept away the entire gas content of such progenitors about ten billion years ago because heating by the cosmic ultraviolet background kept the gas loosely bound: a tiny stellar component embedded in a relatively massive dark halo survived until today. All luminous galaxies should be surrounded by a few extremely dark-matter-dominated dwarf spheroidal satellites, and these should have the shortest orbital periods among dwarf spheroidals because they were accreted early.

HIGH-RESOLUTION SPECTROSCOPY OF EXTREMELY METAL-POOR STARS IN THE LEAST EVOLVED GALAXIES: LEO IV

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

Simon, Joshua D.; McWilliam, Andrew; Thompson, Ian B.

2010-06-10

We present high-resolution Magellan/MIKE spectroscopy of the brightest star in the ultra-faint dwarf galaxy Leo IV. We measure an iron abundance of [Fe/H] = -3.2, adding to the rapidly growing sample of extremely metal-poor (EMP) stars being identified in Milky Way satellite galaxies. The star is enhanced in the {alpha} elements Mg, Ca, and Ti by {approx}0.3 dex, very similar to the typical Milky Way halo abundance pattern. All of the light and iron-peak elements follow the trends established by EMP halo stars, but the neutron-capture elements Ba and Sr are significantly underabundant. These results are quite similar to thosemore » found for stars in the ultra-faint dwarfs Ursa Major II, Coma Berenices, Booetes I, and Hercules, suggesting that the chemical evolution of the lowest-luminosity galaxies may be universal. The abundance pattern we observe is consistent with predictions for nucleosynthesis from a Population III supernova explosion. The extremely low metallicity of this star also supports the idea that a significant fraction ({approx}>10%) of the stars in the faintest dwarfs have metallicities below [Fe/H] = -3.0.« less

The discrepancy between dynamical and theoretical mass in the triplet-system 2MASS J10364483+1521394

NASA Astrophysics Data System (ADS)

Calissendorff, Per; Janson, Markus; Köhler, Rainer; Durkan, Stephen; Hippler, Stefan; Dai, Xiaolin; Brandner, Wolfgang; Schlieder, Joshua; Henning, Thomas

2017-08-01

We combine new Lucky Imaging astrometry from New Technology Telescope/AstraLux Sur with already published astrometry from the AstraLux Large M-dwarf Multiplicity Survey to compute orbital elements and individual masses of the 2MASS J10364483+1521394 triple system belonging to the Ursa-Major moving group. The system consists of one primary low-mass M-dwarf orbited by two less massive companions, for which we determine a combined dynamical mass of MB + C = 0.48 ± 0.14 M⊙. We show from the companions' relative motions that they are of equal mass (with a mass ratio of 1.00 ± 0.03), thus 0.24 ± 0.07 M⊙ individually, with a separation of 3.2 ± 0.3 AU, and we conclude that these masses are significantly higher (30%) than what is predicted by theoretical stellar evolutionary models. The biggest uncertainty remains the distance to the system, here adopted as 20.1 ± 2.0 pc based on trigonometric parallax, whose ambiguity has a major impact on the result. With the new observational data we are able to conclude that the orbital period of the BC pair is 8.41+0.04-0.02yr.

VizieR Online Data Catalog: V-band photometry and RVs of V482 Persei system (Torres+, 2017)

NASA Astrophysics Data System (ADS)

Torres, G.; Lacy, C. H. S.; Fekel, F. C.; Wolf, M.; Muterspaugh, M. W.

2018-05-01

Differential photometry of V482 Per was obtained by measuring images collected with two different robotic telescopes: the URSA WebScope at the University of Arkansas at Fayetteville, AR, and the NFO WebScope near Silver City, NM. All observations were made through a Bessel V filter. Observations were made between 2001 December and 2016 January, and are presented in Tables 1 and 2. V482 Per was monitored spectroscopically with two different instruments. We observed it between 2009 November and 2017 February at the Harvard-Smithsonian Center for Astrophysics (CfA) with the Tillinghast Reflector Echelle Spectrograph (TRES) on the 1.5m Tillinghast reflector at the Fred L. Whipple Observatory (Mount Hopkins, AZ). The wavelength coverage is approximately 3900-9100Å, with a resolving power R~44000. From 2011 November through 2017 April, we additionally acquired 37 useful spectra of V482 Per with the Tennessee State University 2m Automatic Spectroscopic Telescope (AST) and a fiber-fed echelle spectrograph at the Fairborn Observatory in southeast Arizona. We used only the wavelength region from 4920 to 7100Å, with a resolving power R~15000 at 6000Å. (6 data files).

The Little Cub: Discovery of an Extremely Metal-poor Star-forming Galaxy in the Local Universe

NASA Astrophysics Data System (ADS)

Hsyu, Tiffany; Cooke, Ryan J.; Prochaska, J. Xavier; Bolte, Michael

2017-08-01

We report the discovery of the Little Cub, an extremely metal-poor star-forming galaxy in the local universe, found in the constellation Ursa Major (a.k.a. the Great Bear). We first identified the Little Cub as a candidate metal-poor galaxy based on its Sloan Digital Sky Survey photometric colors, combined with spectroscopy using the Kast spectrograph on the Shane 3 m telescope at Lick Observatory. In this Letter, we present high-quality spectroscopic data taken with the Low Resolution Imaging Spectrometer at Keck Observatory, which confirm the extremely metal-poor nature of this galaxy. Based on the weak [O III] λ4363 Å emission line, we estimate a direct oxygen abundance of 12 + log(O/H) = 7.13 ± 0.08, making the Little Cub one of the lowest-metallicity star-forming galaxies currently known in the local universe. The Little Cub appears to be a companion of the spiral galaxy NGC 3359 and shows evidence of gas stripping. We may therefore be witnessing the quenching of a near-pristine galaxy as it makes its first passage about a Milky Way-like galaxy.

Determination of unknown coefficient in a non-linear elliptic problem related to the elastoplastic torsion of a bar

NASA Astrophysics Data System (ADS)

Hasanov, Alemdar; Erdem, Arzu

2008-08-01

The inverse problem of determining the unknown coefficient of the non-linear differential equation of torsional creep is studied. The unknown coefficient g = g({xi}2) depends on the gradient{xi} : = |{nabla}u| of the solution u(x), x [isin] {Omega} [sub] Rn, of the direct problem. It is proved that this gradient is bounded in C-norm. This permits one to choose the natural class of admissible coefficients for the considered inverse problem. The continuity in the norm of the Sobolev space H1({Omega}) of the solution u(x;g) of the direct problem with respect to the unknown coefficient g = g({xi}2) is obtained in the following sense: ||u(x;g) - u(x;gm)||1 [->] 0 when gm({eta}) [->] g({eta}) point-wise as m [->] {infty}. Based on these results, the existence of a quasi-solution of the inverse problem in the considered class of admissible coefficients is obtained. Numerical examples related to determination of the unknown coefficient are presented.

Neutrino Flux Prediction for the NuMI Beamline

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

Aliaga Soplin, Leonidas

2016-01-01

The determination of the neutrino flux in any conventional neutrino beam presents a challenge for the current and future short and long baseline neutrino experiments. The uncertainties associated with the production and attenuation of the hadrons in the beamline materials along with those associated with the beam optics have a big effect in the flux spectrum knowledge. For experiments like MINERvA, understanding the flux is crucial since it enters directly into every neutrino-nucleus cross-sections measurements. The foundation of this work is predicting the neutrino flux at MINERvA using dedicated measurements of hadron production in hadron-nucleus collisions and incorporating in-situ MINERvAmore » data that can provide additional constraints. This work also includes the prospect for predicting the flux at other detectors like the NOvA Near detector. The procedure and conclusions of this thesis will have a big impact on future hadron production experiments and on determining the fl ux for the upcoming DUNE experiment.« less

Revised Uniform Summary of Surface Weather Observations for Vandenberg AFB, California, MSC 723930. Parts A-F

DTIC Science & Technology

1985-05-01

4 sq Al U-X z a’ M 4n al Ni Z u 0I a, -z Con % ui1 ~o* uU cc< 0u :’_ - x LZ Wa IL aw 44 _ X1 9 .j u " ift 13 4 W WIL Of 110’~ aR e Mi Ui 6 U2, D 0 4 u...ginA r ln In n n 4 .0 at ~ N t . I- -iN 0000v 0 v0 0 A0.. 00vN4 - V 0M iNinMfN N. M a 0 P. P. 0000 00000 Samoa 000memo40 gMO P: 1. 0 m9,a a .1 z *J Z...u oa . ow i ob to- fa U F a 0 a 4 0 0 00 Co Eq Eq 0 W vw Moo f - 0 *a 1040 - d - oo - -w_--_ _ 4Fe A AV 42~ PRO i it a 1 -- ’We-- _ - - - te 03 0 0

A service based adaptive U-learning system using UX.

PubMed

Jeong, Hwa-Young; Yi, Gangman

2014-01-01

In recent years, traditional development techniques for e-learning systems have been changing to become more convenient and efficient. One new technology in the development of application systems includes both cloud and ubiquitous computing. Cloud computing can support learning system processes by using services while ubiquitous computing can provide system operation and management via a high performance technical process and network. In the cloud computing environment, a learning service application can provide a business module or process to the user via the internet. This research focuses on providing the learning material and processes of courses by learning units using the services in a ubiquitous computing environment. And we also investigate functions that support users' tailored materials according to their learning style. That is, we analyzed the user's data and their characteristics in accordance with their user experience. We subsequently applied the learning process to fit on their learning performance and preferences. Finally, we demonstrate how the proposed system outperforms learning effects to learners better than existing techniques.

A Service Based Adaptive U-Learning System Using UX

PubMed Central

Jeong, Hwa-Young

2014-01-01

In recent years, traditional development techniques for e-learning systems have been changing to become more convenient and efficient. One new technology in the development of application systems includes both cloud and ubiquitous computing. Cloud computing can support learning system processes by using services while ubiquitous computing can provide system operation and management via a high performance technical process and network. In the cloud computing environment, a learning service application can provide a business module or process to the user via the internet. This research focuses on providing the learning material and processes of courses by learning units using the services in a ubiquitous computing environment. And we also investigate functions that support users' tailored materials according to their learning style. That is, we analyzed the user's data and their characteristics in accordance with their user experience. We subsequently applied the learning process to fit on their learning performance and preferences. Finally, we demonstrate how the proposed system outperforms learning effects to learners better than existing techniques. PMID:25147832

A Refined Nonlinear Analysis of Laminated Composite Plates and Shells.

DTIC Science & Technology

1987-08-01

become (consistent with the assumptions in Eq. (26)1. ga o + 31CI+f C 0~ + g +:0 3 o + gX3 1 + f, 1 3 + fj A cG3 03 a AcaA 03 a~i + g 2 (29) where...g a df/dx3, and 0o u (0 + u0 ) + 10 +u ,( 0 0 + Cie al a 31 + 3~ ~~ 31 31 E (u 1 + u~a C 7 u~3 0 U 0 o 11 01 0 1 0 0 13 1o 1£3 A (um + u a 1 uO) K...A 7 U 3 1heu3 1 x %3 ’fu3x C1 1 10 o 1 1 0 1 00A£3 *- 7f UXI .31 c . £ 0 7f UkaUx *33 7 U31 3 1a *0o.. I 0 ; 111lu (30)633 a= 3SUG £33 f aUa The

Synthetic Spectral Ananlysis of the Nova-Like Variable KQ Mon

NASA Astrophysics Data System (ADS)

Wolfe, Aaron; Sion, E.

2011-01-01

KQ Mon is classified as a nova-like variable with an uncertain orbital period of 0.128 d. Optical spectra (Zwitter, T. & Munari, U.1994, A&AS, 107, 503) reveal no emission lines but strong Balmer absorption features. High speed flickering has been observed indicative of accretion. IUE spectra reveal deep absorption lines due to C III, C II, Si III, Si IV, C IV, He II but no P Cygni profiles indicative of outflow. Its classification in Ritter and Kolb (2006) as a UX UMa type nova-like is uncertain. We have carried out the first synthetic spectral analysis of the IUE archival spectra of KQ Mon with realistic accretion disk models with vertical structure and high gravity photosphere models. The results of our model atmosphere and model accretion disk analyses are presented. We discuss the properties that we have derived for KQ Mon and compare KQ Mon with other nova-like variables viewed at low inclination. This work was supported in part by NSF grant AST0807892 to Villanova University.

A spectrophotometric study of RW Trianguli

NASA Astrophysics Data System (ADS)

Groot, P. J.; Rutten, R. G. M.; van Paradijs, J.

2004-04-01

On the basis of spectrophotometric observations we reconstruct the accretion disk of the eclipsing novalike cataclysmic variable RW Tri in the wavelength region 3600-7000 Å. We find a radial temperature profile that is, on average, consistent with that expected on the basis of the theory of optically thick, steady state accretion disks and infer a mass-accretion rate in RW Tri of ˜10-8 M⊙ yr-1. The line emission is dominated by two areas: one around the hot-spot region and one near the white dwarf. Both emission regions have appreciable vertical extension, and seem to be decoupled from the velocity field in the disk. In our observations RW Tri shows a number of features that are characteristic of the SW Sex sub-class of novalike stars. The appearance of a novalike system as a UX UMa/RW Tri or SW Sex star seems to be mainly governed by the mass-transfer rate from the secondary at the time of observation.

The medium is NOT the message or Indefinitely long-term file storage at Leeds University

NASA Technical Reports Server (NTRS)

Holdsworth, David

1996-01-01

Approximately 3 years ago we implemented an archive file storage system which embodies experiences gained over more than 25 years of using and writing file storage systems. It is the third in-house system that we have written, and all three systems have been adopted by other institutions. This paper discusses the requirements for long-term data storage in a university environment, and describes how our present system is designed to meet these requirements indefinitely. Particular emphasis is laid on experiences from past systems, and their influence on current system design. We also look at the influence of the IEEE-MSS standard. We currently have the system operating in five UK universities. The system operates in a multi-server environment, and is currently operational with UNIX (SunOS4, Solaris2, SGI-IRIX, HP-UX), NetWare3 and NetWare4. PCs logged on to NetWare can also archive and recover files that live on their hard disks.

Invariant graphs of a family of non-uniformly expanding skew products over Markov maps

NASA Astrophysics Data System (ADS)

Walkden, C. P.; Withers, T.

2018-06-01

We consider a family of skew-products of the form where T is a continuous, expanding, locally eventually onto Markov map and is a family of homeomorphisms of . A function is said to be an invariant graph if is an invariant set for the skew-product; equivalently, u(T(x))  =  g x (u(x)). A well-studied problem is to consider the existence, regularity and dimension-theoretic properties of such functions, usually under strong contraction or expansion conditions (in terms of Lyapunov exponents or partial hyperbolicity) in the fibre direction. Here we consider such problems in a setting where the Lyapunov exponent in the fibre direction is zero on a set of periodic orbits but expands except on a neighbourhood of these periodic orbits. We prove that u either has the structure of a ‘quasi-graph’ (or ‘bony graph’) or is as smooth as the dynamics, and we give a criteria for this to happen.

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

Laha, Ranjan; Brodsky, Stanley J.

The discovery of extraterrestrial neutrinos in the 30 TeV { PeV energy range by IceCube provides new constraints on high energy astrophysics. An important background to the signal are the prompt neutrinos which originate from the decay of charm hadrons produced by high energy cosmic- ray particles interacting in the Earth's atmosphere. It is conventional to use pQCD calculations of charm hadroproduction based on gluon splitting g ! c c alone. However, QCD predicts an additional \\intrinsic" component of the heavy quark distribution which arises from diagrams where heavy quarks are multiply connected to the proton's valence quarks. We estimatemore » the prompt neutrino spectrum due to intrinsic charm. We nd that the atmospheric prompt neutrino ux from intrinsic charm is comparable to the pQCD contribution once we normalize the intrinsic charm di erential cross sections to the ISR and the LEBC-MPS collaboration data. In future, IceCube will constrain the intrinsic charm content of the proton and will contribute to one of the major uncertainties in high energy physics phenomenology.« less

Spectral Element Method for the Simulation of Unsteady Compressible Flows

NASA Technical Reports Server (NTRS)

Diosady, Laslo Tibor; Murman, Scott M.

2013-01-01

This work uses a discontinuous-Galerkin spectral-element method (DGSEM) to solve the compressible Navier-Stokes equations [1{3]. The inviscid ux is computed using the approximate Riemann solver of Roe [4]. The viscous fluxes are computed using the second form of Bassi and Rebay (BR2) [5] in a manner consistent with the spectral-element approximation. The method of lines with the classical 4th-order explicit Runge-Kutta scheme is used for time integration. Results for polynomial orders up to p = 15 (16th order) are presented. The code is parallelized using the Message Passing Interface (MPI). The computations presented in this work are performed using the Sandy Bridge nodes of the NASA Pleiades supercomputer at NASA Ames Research Center. Each Sandy Bridge node consists of 2 eight-core Intel Xeon E5-2670 processors with a clock speed of 2.6Ghz and 2GB per core memory. On a Sandy Bridge node the Tau Benchmark [6] runs in a time of 7.6s.

Pure rotational spectra of TiO and TiO2 in VY Canis Majoris

NASA Astrophysics Data System (ADS)

Kamiński, T.; Gottlieb, C. A.; Menten, K. M.; Patel, N. A.; Young, K. H.; Brünken, S.; Müller, H. S. P.; McCarthy, M. C.; Winters, J. M.; Decin, L.

2013-03-01

We report the first detection of pure rotational transitions of TiO and TiO2 at (sub-)millimeter wavelengths towards the red supergiant VY CMa. A rotational temperature, Trot, of about 250 K was derived for TiO2. Although Trot was not well constrained for TiO, it is likely somewhat higher than that of TiO2. The detection of the Ti oxides confirms that they are formed in the circumstellar envelopes of cool oxygen-rich stars and may be the "seeds" of inorganic-dust formation, but alternative explanations for our observation of TiO and TiO2 in the cooler regions of the envelope cannot be ruled out at this time. The observations suggest that a significant fraction of the oxides is not converted to dust, but instead remains in the gas phase throughout the outflow. Based on observations carried out with the Submillimeter Array and IRAM Plateau de Bure Interferometer.Plateau de Bure data (FITS file) is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A113

Laboratory Studies Of Astrophysically-interesting Phosphorus-bearing Molecules

NASA Astrophysics Data System (ADS)

Ziurys, Lucy M.; Halfen, D. T.; Sun, M.; Clouthier, D. J.

2009-05-01

Over the past year, there has been a renewed interest in the presence of phosphorus-containing molecules in the interstellar medium. Recent observations have increased the number of known interstellar phosphorus-bearing species from two (PN, CP) to six with the identification of HCP, CCP, and PH3 in the carbon-rich circumstellar shell of IRC+10216 and PO in the oxygen-rich envelope of VY Canis Majoris. More species of this type may be present in the ISM, but laboratory rest frequencies, necessary for such detections, are not generally known for many potential molecules. To fill in this gap, we have been conducting measurements of the pure rotational spectra of phosphorus-containing molecules of astrophysical interest, using both millimeter/submm direct absorption and Fourier transform microwave (FTMW) spectroscopy. We have developed a new phosphorus source for this purpose. These methods cover the frequency ranges 65-850 GHz and 4-40 GHz, respectively. Our recent study of the CCP radical (X2Πr) using both of these techniques has resulted in its identification in IRC+10216. Rotational spectra of other molecules such as PCN, HPS, and CH3PH2 have been recorded. We will report on these species and additional new laboratory developments

ALMA sub-mm maser and dust distribution of VY Canis Majoris

NASA Astrophysics Data System (ADS)

Richards, A. M. S.; Impellizzeri, C. M. V.; Humphreys, E. M.; Vlahakis, C.; Vlemmings, W.; Baudry, A.; De Beck, E.; Decin, L.; Etoka, S.; Gray, M. D.; Harper, G. M.; Hunter, T. R.; Kervella, P.; Kerschbaum, F.; McDonald, I.; Melnick, G.; Muller, S.; Neufeld, D.; O'Gorman, E.; Parfenov, S. Yu.; Peck, A. B.; Shinnaga, H.; Sobolev, A. M.; Testi, L.; Uscanga, L.; Wootten, A.; Yates, J. A.; Zijlstra, A.

2014-12-01

Aims: Cool, evolved stars have copious, enriched winds. Observations have so far not fully constrained models for the shaping and acceleration of these winds. We need to understand the dynamics better, from the pulsating stellar surface to ~10 stellar radii, where radiation pressure on dust is fully effective. Asymmetric nebulae around some red supergiants imply the action of additional forces. Methods: We retrieved ALMA Science Verification data providing images of sub-mm line and continuum emission from VY CMa. This enables us to locate water masers with milli-arcsec accuracy and to resolve the dusty continuum. Results: The 658, 321, and 325 GHz masers lie in irregular, thick shells at increasing distances from the centre of expansion. For the first time this is confirmed as the stellar position, coinciding with a compact peak offset to the NW of the brightest continuum emission. The maser shells overlap but avoid each other on scales of up to 10 au. Their distribution is broadly consistent with excitation models but the conditions and kinematics are complicated by wind collisions, clumping, and asymmetries. Appendices are available in electronic form at http://www.aanda.org

The Infrared Continuum Spectrum of VY Canis Majoris

NASA Astrophysics Data System (ADS)

Harwit, Martin; Malfait, Koen; Decin, Leen; Waelkens, Christoffel; Feuchtgruber, Helmut; Melnick, Gary J.

2001-08-01

We combine spectra of VY CMa obtained with the short- and long-wavelength spectrometers, SWS and LWS, on the Infrared Space Observatory3 to provide a first detailed continuum spectrum of this highly luminous star. The circumstellar dust cloud through which the star is observed is partially self-absorbing, which makes for complex computational modeling. We review previous work and comment on the range of uncertainties about the physical traits and mineralogical composition of the modeled disk. We show that these uncertainties significantly affect the modeling of the outflow and the estimated mass loss. In particular, we demonstrate that a variety of quite diverse models can produce good fits to the observed spectrum. If the outflow is steady, and the radiative repulsion on the dust cloud dominates the star's gravitational attraction, we show that the total dust mass loss rate is ~4×10-6 Msolar yr-1, assuming that the star is at a distance of 1.5 kpc. Several indications, however, suggest that the outflow from the star may be spasmodic. We discuss this and other problems facing the construction of a physically coherent model of the dust cloud and a realistic mass-loss analysis.

Hubble Space Telescope Imaging of the Mass-losing Supergiant VY Canis Majoris

NASA Astrophysics Data System (ADS)

Kastner, Joel H.; Weintraub, David A.

1998-04-01

The highly luminous M supergiant VY CMa is a massive star that appears to be in its final death throes, losing mass at high rate en route to exploding as a supernova. Subarcsecond-resolution optical images of VY CMa, obtained with the Faint Object Camera (FOC) aboard the Hubble Space Telescope, vividly demonstrate that mass loss from VY CMa is highly anisotropic. In the FOC images, the optical ``star'' VY CMa constitutes the bright, well-resolved core of an elongated reflection nebula. The imaged nebula is ~3" (~4500 AU) in extent and is clumpy and highly asymmetric. The images indicate that the bright core, which lies near one edge of the nebula, is pure scattered starlight. We conclude that at optical wavelengths VY CMa is obscured from view along our line of sight by its own dusty envelope. The presence of the extended reflection nebula then suggests that this envelope is highly flattened and/or that the star is surrounded by a massive circumstellar disk. Such axisymmetric circumstellar density structure should have profound effects on post-red supergiant mass loss from VY CMa and, ultimately, on the shaping of the remnant of the supernova that will terminate its post-main-sequence evolution.

Metal-Containing Molecules Beyond the Solar System: a Laboratory and Radio Astronomical Perspective

NASA Astrophysics Data System (ADS)

Ziurys, L. M.

2010-06-01

Although the history of interstellar molecules began around 1970, with the millimeter-wave detection of CO in the Orion Nebula, metal-containing species have been somewhat elusive for astronomical searches. Only in the past two decades have metal-bearing molecules been identified in space, starting with metal halides (NaCl, KCl, AlCl, and AlF), and then metal cyanide and isocyanide species (MgNC, MgCN, NaCN, and AlNC). Moreover, the metal-containing molecules seemed to be present in a single astronomical object: the envelope of a dying, carbon-rich star, IRC+10216. However, with improvements both in laboratory spectroscopy and telescope sensitivity, it is becoming clear that the relevance of metal-containing species in astrophysics is increasing. Metal oxide and hydroxide species, such as AlO and AlOH, have recently been identified in interstellar space. Metal-containing molecules are now being found in other astronomical sources, such as the oxygen-rich shell surrounding VY Canis Majoris, a supergiant star. These new astronomical discoveries will be presented, as well as the laboratory measurements that made them possible. New directions in rotational spectroscopy of metal-bearing molecules will also be discussed.

Mid-Infrared Interferometry on Spectral Lines. III. Ammonia and Silane around IRC +10216 and VY Canis Majoris

NASA Astrophysics Data System (ADS)

Monnier, J. D.; Danchi, W. C.; Hale, D. S.; Tuthill, P. G.; Townes, C. H.

2000-11-01

Using the University of California Berkeley Infrared Spatial Interferometer with a radio frequency (RF) filter bank, the first interferometric observations of mid-infrared molecular absorption features of ammonia (NH3) and silane (SiH4) with very high spectral resolution (λ/Δλ~105) were made. Under the assumptions of spherical symmetry and uniform outflow, these new data permitted the molecular stratification around carbon star IRC +10216 and red supergiant VY CMa to be investigated. For IRC +10216, both ammonia and silane were found to form in the dusty outflow significantly beyond both the dust formation and gas acceleration zones. Specifically, ammonia was found to form before silane in a region of decaying gas turbulence (>~20R*), while the silane is produced in a region of relatively smooth gas flow much farther from the star (>~80R*). The depletion of gas-phase SiS onto grains soon after dust formation may fuel silane-producing reactions on the grain surfaces. For VY CMa, a combination of interferometric and spectral observations suggest that NH3 is forming near the termination of the gas acceleration phase in a region of high gas turbulence (~40R*).

Hubble Observes Galaxies' Evolution in Slow Motion

NASA Image and Video Library

2017-12-08

It is known today that merging galaxies play a large role in the evolution of galaxies and the formation of elliptical galaxies in particular. However there are only a few merging systems close enough to be observed in depth. The pair of interacting galaxies seen here — known as NGC 3921 — is one of these systems. NGC 3921 — found in the constellation of Ursa Major (The Great Bear) — is an interacting pair of disk galaxies in the late stages of its merger. Observations show that both of the galaxies involved were about the same mass and collided about 700 million years ago. You can see clearly in this image the disturbed morphology, tails and loops characteristic of a post-merger. The clash of galaxies caused a rush of star formation and previous Hubble observations showed over 1,000 bright, young star clusters bursting to life at the heart of the galaxy pair. Image credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Star-Hopping

NASA Astrophysics Data System (ADS)

Garfinkle, Robert A.

1997-07-01

Introduction; Preface; Acknowledgements; 1. How to use this book and what you are going to see; 2. How the sky works, determining your field of view, observing tips and how to navigate in the night sky; 3. January - Taurus and Orion: the bull and hunter; 4. February - Canis Minor, Canis Major, and Puppis: dog days in February and Jason's Argo; 5. March - Cancer, Leo, and Corvus: a crab, the king of the beasts, and a crow; 6. April - Ursa Major: a dipper round tripper; 7. May - Coma Berenices and Virgo: the sparkling hair of Berenice and the wheat maiden and her bushel of galaxies; 8. June - Libra and Lupus: the balance scales and the wolf; 9. July - Scorpius, Sagittarius, and Scutum: the scorpion, archer, and shield of John Sobieski; 10. August - Draco: following the trail of the dragon; 11. September - Cygnus, Lyra, Vulpecula, and Sagitta: the swan, lyre, fox, and arrow; 12. October - Andromeda and Perseus: the chained lady and her rescuer; 13. November - Cepheus and Cassiopeia: the king and queen of Joppa; 14. December - Pisces, Triangulum, and Aries: of fishes, a triangle, and a ram; 15. Messier Marathon, a sundown to sunup hop across the skies; Appendix A: Classification tables; Appendix B: The constellations; Appendix C: The Greek alphabet; Appendix D: Decimalization of the day; Glossary; Bibliography; Index.

VizieR Online Data Catalog: The G+M eclipsing binary V530 Orionis photometry (Torres+, 2014)

NASA Astrophysics Data System (ADS)

Torres, G.; Lacy, C. H. S.; Pavlovski, K.; Feiden, G. A.; Sabby, J. A.; Bruntt, H.; Clausen, J. V.

2017-08-01

V530 Ori was monitored spectroscopically with three different instruments over a period of more than 17 yr. Observations began at the Harvard-Smithsonian Center for Astrophysics (CfA) in 1996 June with a Cassegrain-mounted echelle spectrograph ("Digital Speedometer", DS; Latham 1992ASPC...32..110L) attached to the 1.5 m Tillinghast reflector at the F. L. Whipple Observatory (Mount Hopkins, AZ). We gathered a further 30 spectra of V530 Ori at the Kitt Peak National Observatory (KPNO) from 1999 March to 2001 January, using the coude-feed telescope and the coude spectrometer. Finally, 41 additional observations were obtained at the CfA from 2009 November to 2014 March with the Tillinghast Reflector Echelle Spectrograph (TRES; Furesz 2008, PhD thesis , Univ. Szeged, Hungary) on the 1.5 m telescope mentioned earlier. Two sets of V-band images of V530 Ori were obtained with independent robotic telescopes operating at the University of Arkansas (URSA WebScope) and near Silver City, NM (NFO WebScope) from 2001 January to 2012 February. Differential photometric measurements of V530 Ori were also gathered with the Stromgren Automatic Telescope at ESO (La Silla, Chile), during several campaigns from 2001 January to 2006 February. (5 data files).

Why Are Galaxies So Smooth?

NASA Image and Video Library

2009-04-30

This image from NASA's Spitzer Space Telescope shows the spiral galaxy NGC 2841, located about 46 million light-years from Earth in the constellation Ursa Major. The galaxy is helping astronomers solve one of the oldest puzzles in astronomy: Why do galaxies look so smooth, with stars sprinkled evenly throughout? An international team of astronomers has discovered that rivers of young stars flow from their hot, dense stellar nurseries, dispersing out to form large, smooth distributions. This image is a composite of three different wavelengths from Spitzer's infrared array camera. The shortest wavelengths are displayed inblue, and mostly show the older stars in NGC 2841, as well as foreground stars in our own Milky Way galaxy. The cooler areas are highlighted in red, and show the dusty, gaseous regions of the galaxy. Blue shows infrared light of 3.6 microns, green represents 4.5-micron light and red, 8.0-micron light. The contribution from starlight measured at 3.6 microns has been subtracted from the 8.0-micron data to enhance the visibility of the dust features.The shortest wavelengths are displayed inblue, and mostly show the older stars in NGC 2841, as well as foreground stars in our own Milky Way galaxy. http://photojournal.jpl.nasa.gov/catalog/PIA12001

$$\\mathscr{H}_2$$ optimal control techniques for resistive wall mode feedback in tokamaks

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

Clement, Mitchell; Hanson, Jeremy; Bialek, Jim

DIII-D experiments show that a new, advanced algorithm improves resistive wall mode (RWM) stability control in high performance discharges using external coils. DIII-D can excite strong, locked or nearly locked external kink modes whose rotation frequencies and growth rates are on the order of the magnetic ux di usion time of the vacuum vessel wall. The VALEN RWM model has been used to gauge the e ectiveness of RWM control algorithms in tokamaks. Simulations and experiments have shown that modern control techniques like Linear Quadratic Gaussian (LQG) control will perform better, using 77% less current, than classical techniques when usingmore » control coils external to DIII-D's vacuum vessel. Experiments were conducted to develop control of a rotating n = 1 perturbation using an LQG controller derived from VALEN and external coils. Feedback using this LQG algorithm outperformed a proportional gain only controller in these perturbation experiments over a range of frequencies. Results from high N experiments also show that advanced feedback techniques using external control coils may be as e ective as internal control coil feedback using classical control techniques.« less

Observational studies of the clearing phase in proto-planetary disk systems

NASA Technical Reports Server (NTRS)

Grady, Carol A.

1994-01-01

A summary of the work completed during the first year of a 5 year program to observationally study the clearing phase of proto-planetary disks is presented. Analysis of archival and current IUE data, together with supporting optical observations has resulted in the identification of 6 new proto-planetary disk systems associated with Herbig Ae/Be stars, the evolutionary precursors of the beta Pictoris system. These systems exhibit large amplitude light and optical color variations which enable us to identify additional systems which are viewed through their circumstellar disks including a number of classical T Tauri stars. On-going IUE observations of Herbig Ae/Be and T Tauri stars with this orientation have enabled us to detect bipolar emission plausibly associated with disk winds. Preliminary circumstellar extinction studies were completed for one star, UX Ori. Intercomparison of the available sample of edge-on systems, with stars ranging from 1-6 solar masses, suggests that the signatures of accreting gas, disk winds, and bipolar flows and the prominence of a dust-scattered light contribution to the integrated light of the system decreases with decreasing IR excess.

Discovery of a New Classical Nova Shell Around a Nova-like Cataclysmic Variable

NASA Astrophysics Data System (ADS)

Guerrero, Martín A.; Sabin, Laurence; Tovmassian, Gagik; Santamaría, Edgar; Michel, Raul; Ramos-Larios, Gerardo; Alarie, Alexandre; Morisset, Christophe; Bermúdez Bustamante, Luis C.; González, Chantal P.; Wright, Nicholas J.

2018-04-01

The morphology and optical spectrum of IPHASX J210204.7+471015, a nebula classified as a possible planetary nebula are, however, strikingly similar to those of AT Cnc, a classical nova shell around a dwarf nova. To investigate its true nature, we have obtained high-resolution narrowband [O III] and [N II] images and deep optical spectra. The nebula shows an arc of [N II]-bright knots notably enriched in nitrogen, while an [O III]-bright bow shock is progressing throughout the ISM. Diagnostic line ratios indicate that shocks are associated with the arc and bow shock. The central star of this nebula has been identified by its photometric variability. Time-resolved photometric and spectroscopic data of this source reveal a period of 4.26 hr, which is attributed to a binary system. The optical spectrum is notably similar to that of RW Sex, a cataclysmic variable star (CV) of the UX UMa nova-like (NL) type. Based on these results, we propose that IPHASX J210204.7 + 471015 is a classical nova shell observed around a CV-NL system in quiescence.

Characterization of an ultraviolet imaging detector with high event rate ROIC (HEROIC) readout

NASA Astrophysics Data System (ADS)

Nell, Nicholas; France, Kevin; Harwit, Alex; Bradley, Scott; Franka, Steve; Freymiller, Ed; Ebbets, Dennis

2016-07-01

We present characterization results from a photon counting imaging detector consisting of one microchannel plate (MCP) and an array of two readout integrated circuits (ROIC) that record photon position. The ROICs used in the position readout are the high event rate ROIC (HEROIC) devices designed to handle event rates up to 1 MHz per pixel, recently developed by the Ball Aerospace and Technologies Corporation in collaboration with the University of Colorado. An opaque cesium iodide (CsI) photocathode sensitive in the far-ultraviolet (FUV; 122-200 nm), is deposited on the upper surface of the MCP. The detector is characterized in a chamber developed by CU Boulder that is capable of illumination with vacuum-ultraviolet (VUV) monochromatic light and measurement of absolute ux with a calibrated photodiode. Testing includes investigation of the effects of adjustment of internal settings of the HEROIC devices including charge threshold, gain, and amplifier bias. The detector response to high count rates is tested. We report initial results including background, uniformity, and quantum detection efficiency (QDE) as a function of wavelength.

NASA GTE TRACE-P Augmentation

NASA Technical Reports Server (NTRS)

Sandholm, Scott; Conners, Vickie (Technical Monitor)

2005-01-01

There were three major tasks and objectives that the Tropospheric Trace Gas and Airborne Measurement Group's (TTGAMG) worked on for different aspects of this grant: 1) Migrate the data acquisition system from HP-UX to Linux, thus reducing future costs as the result of software and operating system (OS) upgrades and improving upon usability as membership in the group changes; 2) Rework the Optical Parametric Oscillator (OPO) cavities. These are the OPOs that are integral to the Georgia Institute of Technology Airborne Laser Induced Fluorescent Experiment (GITALIFE) that the TTGAMG flew on TRACE-P. The objective was to improve upon optimizing the pump laser energy and narrowing the linewidth of the UV wavelength generated by the OPOs; 3) Improve and expand the interactive website on http://tmbk2.eas.gatech.edu by adding 3-D graphing, improve the response time for Joe Surfer Dude, improve performance, usability, and expand the database. If I were to assign a letter grade to each of the above tasks, I would give the TTGAMG two Bs and an A to the tasks listed above.

Facile Reductive Silylation of UO22+ to Uranium(IV) Chloride.

PubMed

Kiernicki, John J; Zeller, Matthias; Bart, Suzanne C

2017-01-19

General reductive silylation of the UO 2 2+ cation occurs readily in a one-pot, two-step stoichiometric reaction at room temperature to form uranium(IV) siloxides. Addition of two equivalents of an alkylating reagent to UO 2 X 2 (L) 2 (X=Cl, Br, I, OTf; L=triphenylphosphine oxide, 2,2'-bipyridyl) followed by two equivalents of a silyl (pseudo)halide, R 3 Si-X (R=aryl, alkyl, H; X=Cl, Br, I, OTf, SPh), cleanly affords (R 3 SiO) 2 UX 2 (L) 2 in high yields. Support is included for the key step in the process, reduction of U VI to U V . This procedure is applicable to a wide range of commercially available uranyl salts, silyl halides, and alkylating reagents. Under this protocol, one equivalent of SiCl 4 or two equivalents of Me 2 SiCl 2 results in direct conversion of the uranyl to uranium(IV) tetrachloride. Full spectroscopic and structural characterization of the siloxide products is reported. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

UNIX-based operating systems robustness evaluation

NASA Technical Reports Server (NTRS)

Chang, Yu-Ming

1996-01-01

Robust operating systems are required for reliable computing. Techniques for robustness evaluation of operating systems not only enhance the understanding of the reliability of computer systems, but also provide valuable feed- back to system designers. This thesis presents results from robustness evaluation experiments on five UNIX-based operating systems, which include Digital Equipment's OSF/l, Hewlett Packard's HP-UX, Sun Microsystems' Solaris and SunOS, and Silicon Graphics' IRIX. Three sets of experiments were performed. The methodology for evaluation tested (1) the exception handling mechanism, (2) system resource management, and (3) system capacity under high workload stress. An exception generator was used to evaluate the exception handling mechanism of the operating systems. Results included exit status of the exception generator and the system state. Resource management techniques used by individual operating systems were tested using programs designed to usurp system resources such as physical memory and process slots. Finally, the workload stress testing evaluated the effect of the workload on system performance by running a synthetic workload and recording the response time of local and remote user requests. Moderate to severe performance degradations were observed on the systems under stress.

Dynamics of a Nonlocal Dispersal Model with a Nonlocal Reaction Term

NASA Astrophysics Data System (ADS)

Ma, Li; Guo, Shangjiang; Chen, Ting

In this paper, we study a class of nonlocal dispersal problem with a nonlocal term arising in population dynamics: ut = 𝒟u + u λ ‑ f(u) ‑∫ΩK(x,y)g(u(y))dy,in Ω × (0, +∞), u(x, 0) = u0(x) ≥ 0, in Ω,u = 0, in ℝN\\Ω × (0, +∞), where Ω ⊂ ℝN (N ≥ 1) is a bounded domain, λ ∈ ℝ, 𝒟u(x,t) =∫ΩJ(x ‑ y)[u(y,t) ‑ u(x,t)]dy represents the nonlocal dispersal operator with continuous and non-negative dispersal kernel. The kernel K ∈ C(Ω¯ ×Ω¯) is assumed to be non-negative and is allowed to have a degeneracy in a smooth subdomain Ω0 of Ω. When K is either positive or vanishes in a subdomain, we respectively investigate the existence, multiplicity and asymptotical stability of positive steady states under the local/global variation of parameter by means of sub-supersolution method, Lyapunov-Schmidt reduction, and bifurcation theory.

Radiation Coupling with the FUN3D Unstructured-Grid CFD Code

NASA Technical Reports Server (NTRS)

Wood, William A.

2012-01-01

The HARA radiation code is fully-coupled to the FUN3D unstructured-grid CFD code for the purpose of simulating high-energy hypersonic flows. The radiation energy source terms and surface heat transfer, under the tangent slab approximation, are included within the fluid dynamic ow solver. The Fire II flight test, at the Mach-31 1643-second trajectory point, is used as a demonstration case. Comparisons are made with an existing structured-grid capability, the LAURA/HARA coupling. The radiative surface heat transfer rates from the present approach match the benchmark values within 6%. Although radiation coupling is the focus of the present work, convective surface heat transfer rates are also reported, and are seen to vary depending upon the choice of mesh connectivity and FUN3D ux reconstruction algorithm. On a tetrahedral-element mesh the convective heating matches the benchmark at the stagnation point, but under-predicts by 15% on the Fire II shoulder. Conversely, on a mixed-element mesh the convective heating over-predicts at the stagnation point by 20%, but matches the benchmark away from the stagnation region.

A Riemann-Hilbert Approach for the Novikov Equation

NASA Astrophysics Data System (ADS)

Boutet de Monvel, Anne; Shepelsky, Dmitry; Zielinski, Lech

2016-09-01

We develop the inverse scattering transform method for the Novikov equation u_t-u_{txx}+4u^2u_x=3u u_xu_{xx}+u^2u_{xxx} considered on the line xin(-∞,∞) in the case of non-zero constant background. The approach is based on the analysis of an associated Riemann-Hilbert (RH) problem, which in this case is a 3× 3 matrix problem. The structure of this RH problem shares many common features with the case of the Degasperis-Procesi (DP) equation having quadratic nonlinear terms (see [Boutet de Monvel A., Shepelsky D., Nonlinearity 26 (2013), 2081-2107, arXiv:1107.5995]) and thus the Novikov equation can be viewed as a ''modified DP equation'', in analogy with the relationship between the Korteweg-de Vries (KdV) equation and the modified Korteweg-de Vries (mKdV) equation. We present parametric formulas giving the solution of the Cauchy problem for the Novikov equation in terms of the solution of the RH problem and discuss the possibilities to use the developed formalism for further studying of the Novikov equation.

$$\\mathscr{H}_2$$ optimal control techniques for resistive wall mode feedback in tokamaks

DOE PAGES

Clement, Mitchell; Hanson, Jeremy; Bialek, Jim; ...

2018-02-28

DIII-D experiments show that a new, advanced algorithm improves resistive wall mode (RWM) stability control in high performance discharges using external coils. DIII-D can excite strong, locked or nearly locked external kink modes whose rotation frequencies and growth rates are on the order of the magnetic ux di usion time of the vacuum vessel wall. The VALEN RWM model has been used to gauge the e ectiveness of RWM control algorithms in tokamaks. Simulations and experiments have shown that modern control techniques like Linear Quadratic Gaussian (LQG) control will perform better, using 77% less current, than classical techniques when usingmore » control coils external to DIII-D's vacuum vessel. Experiments were conducted to develop control of a rotating n = 1 perturbation using an LQG controller derived from VALEN and external coils. Feedback using this LQG algorithm outperformed a proportional gain only controller in these perturbation experiments over a range of frequencies. Results from high N experiments also show that advanced feedback techniques using external control coils may be as e ective as internal control coil feedback using classical control techniques.« less

SOLID SOLUTION EFFECTS ON THE THERMAL PROPERTIES IN THE MgAl2O4-MgGa2O4

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

O'Hara, Kelley; Smith, Jeffrey D; Sander, Todd P.

Solid solution eects on thermal conductivity within the MgO-Al2O3-Ga2O3 system were studied. Samples with systematically varied additions of MgGa2O4 to MgAl2O4 were prepared and the laser ash technique was used to determine thermal diusivity at temperatures between 200C and 1300C. Heat capacity as a function of temperature from room temperature to 800C was also determined using dierential scanning calorimetry. Solid solution in the MgAl2O4-MgGa2O4 system decreases the thermal conductivity up to 1000C. At 200C thermal conductivity decreased 24% with a 5 mol% addition of MgGa2O4 to the system. At 1000C the thermal conductivity decreased 13% with a 5 mol% addition.more » Steady state calculations showed a 12.5% decrease in heat ux with 5 mol% MgGa2O4 considered across a 12 inch thickness.« less

Dollar Summary of Federal Supply Classification and Service Category by Company, FY 85. Part 10 (7035-9150).

DTIC Science & Technology

1985-01-01

U nU p U ) ( A W c AV )U IlDl00 0 (0 0 0a( 0C x III z z zzzz .II, I_ . b4 " " . Iac ) tNe x x x k~e Y e x x w f1 e h L&, ala. " " . . . . ala aL a...4 1 4 1 4 14 w4 m4 14 14 u4 14 14 w4 14 LL Z 4 " 15. x. "n 1-2111 w < f1 -40 >- co0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 z a10 LA 01 U)X 2 2 2...a a acca ala a an 1 am W n U A ( n U maA U n ( ) C U ) ( ) V )( 0ma, a 0 C Dc ( p0 . ma a D ( D C D 0 c 9 c 9 C 9 0 C amaw w w w w iu jw w L w u L L

Using Cassini CIRS Data to Constrain Enceladus' Libration State

NASA Technical Reports Server (NTRS)

Hurford, T. A.; Helfenstein, P.; Spencer, J. R.; Nimmo, P.

2010-01-01

Given the non-spherical shape of Enceladus, the satellite may experience gravitational torques that will cause it to physically librate as it orbits Saturn. Physical libration would produce a diurnal oscillation in the longitude of Enceladus' tidal bulge, which could have a profound effect on the diurnal stresses experienced by the surface of the satellite. Although Cassini ISS has placed an observational upper limit on Enceladus' libration amplitude, small amplitude librations may have geologically significant consequences. For example, a physical libration will affect heat production along the tiger stripes as produced by tidal shear heating. We have modeled the expected power emitted along the tiger stripes for various types of physical libration and have quantified which types of physical libration best reproduce the observed power f1ux as detailed in Cassini CIRS data. We find that including a physical libration does allow better fits to the observations and we have identified regions of the libration phase space that where these fits are optimized. A physical libration has important implications for tidal dissipation within Ence1adus and if identified may provide an additional constraint on its interior mass distribution.

Accretion and outflow activity on the late phases of pre-main-sequence evolution. The case of RZ Piscium

NASA Astrophysics Data System (ADS)

Potravnov, I. S.; Mkrtichian, D. E.; Grinin, V. P.; Ilyin, I. V.; Shakhovskoy, D. N.

2017-03-01

RZ Psc is an isolated high-latitude post-T Tauri star that demonstrates a UX Ori-type photometric activity. The star shows very weak spectroscopic signatures of accretion, but at the same time possesses the unusual footprints of the wind in Na I D lines. In the present work we investigate new spectroscopic observations of RZ Psc obtained in 2014 during two observation runs. We found variable blueshifted absorption components (BACs) in lines of the other alcali metals, K I 7699 Å and Ca II IR triplet. We also confirmed the presence of a weak emission component in the Hα line, which allowed us to estimate the mass accretion rate on the star as Ṁ ≤ 7 × 10-12M⊙ yr-1. We could not reveal any clear periodicity in the appearance of BACs in sodium lines. Nevertheless, the exact coincidence of the structure and velocities of the Na I D absorptions observed with the interval of about one year suggests that such a periodicity should exist.

Debunking the Myth of Two-Temperature Coronae for RS CVn Systems Using Contemporaneous

NASA Astrophysics Data System (ADS)

Linsky, Jeffrey L.

For many years the standard analysis of low energy resolution x-ray observations of active late-type stars with the IPC, PSPC, TGS, and SSS has been to assume that the stellar coronae have plasma at only two temperatures. This type of analysis is constrained by the small information content and limited bandpass of the data but has NO PHYSICAL BASIS WHATSOEVER. We propose to test this hypothesis and to go beyond it to derive continuous emission measure distributions for the coronae of three very bright RS CVn systems (sigma-2 Cor Bor, UX Ari and VY Ari) using CONTEMPORANEOUS high resolution EUVE spectra and the improved x-ray energy resolution of ASCA. EUVE provides Fe lines with a broad range of ionization to derive the emission measure EM(T) independent of any uncertainties in the coronal abundances, while ASCA provides information on the hot plasma as seen in blended features of Mg, Si, S, and Fe and can test for coronal abundances different from the photosphere. We will model the quiescent and flare emission with magnetic loops.

Transient dynamics capability at Sandia National Laboratories

NASA Technical Reports Server (NTRS)

Attaway, Steven W.; Biffle, Johnny H.; Sjaardema, G. D.; Heinstein, M. W.; Schoof, L. A.

1993-01-01

A brief overview of the transient dynamics capabilities at Sandia National Laboratories, with an emphasis on recent new developments and current research is presented. In addition, the Sandia National Laboratories (SNL) Engineering Analysis Code Access System (SEACAS), which is a collection of structural and thermal codes and utilities used by analysts at SNL, is described. The SEACAS system includes pre- and post-processing codes, analysis codes, database translation codes, support libraries, Unix shell scripts for execution, and an installation system. SEACAS is used at SNL on a daily basis as a production, research, and development system for the engineering analysts and code developers. Over the past year, approximately 190 days of CPU time were used by SEACAS codes on jobs running from a few seconds up to two and one-half days of CPU time. SEACAS is running on several different systems at SNL including Cray Unicos, Hewlett Packard PH-UX, Digital Equipment Ultrix, and Sun SunOS. An overview of SEACAS, including a short description of the codes in the system, are presented. Abstracts and references for the codes are listed at the end of the report.

Infrared observations of RS CVn stars

NASA Technical Reports Server (NTRS)

Berriman, G.; De Campli, W. M.; Werner, M. W.; Hatchett, S. P.

1983-01-01

The paper presents infrared photometry of the RS CVn binary stars AR Lac (1.2-10 microns) and MM Her (1.2-3.5 microns) as they egressed from their primary and secondary eclipses; of the eclipsing systems RS CVn and Z Her at maximum light (1.2-10 microns) and of the non-eclipsing systems UX Ari and HR 1099 (1.2-10 microns). An analysis of these and published V data based on flux ratio diagrams (linear analogues of color-color diagrams) shows that G and K stars supply the infrared light of these systems. In AR Lac, the combined light of a G5-K0 subgiant and either a late F dwarf or an early F subgiant can account for the observed visual and infrared light curves. None of these systems shows infrared emission from circumstellar matter. This result is simply understood: dust grains would not be expected to form in the physical conditions surrounding the subgiant, and the corona and chromosphere (whose properties have been deduced from spectroscopic X-ray observations) should not produce appreciable infrared emission.

Validation of Magnetospheric Magnetohydrodynamic Models

NASA Astrophysics Data System (ADS)

Curtis, Brian

Magnetospheric magnetohydrodynamic (MHD) models are commonly used for both prediction and modeling of Earth's magnetosphere. To date, very little validation has been performed to determine their limits, uncertainties, and differences. In this work, we performed a comprehensive analysis using several commonly used validation techniques in the atmospheric sciences to MHD-based models of Earth's magnetosphere for the first time. The validation techniques of parameter variability/sensitivity analysis and comparison to other models were used on the OpenGGCM, BATS-R-US, and SWMF magnetospheric MHD models to answer several questions about how these models compare. The questions include: (1) the difference between the model's predictions prior to and following to a reversal of Bz in the upstream interplanetary field (IMF) from positive to negative, (2) the influence of the preconditioning duration, and (3) the differences between models under extreme solar wind conditions. A differencing visualization tool was developed and used to address these three questions. We find: (1) For a reversal in IMF Bz from positive to negative, the OpenGGCM magnetopause is closest to Earth as it has the weakest magnetic pressure near-Earth. The differences in magnetopause positions between BATS-R-US and SWMF are explained by the influence of the ring current, which is included in SWMF. Densities are highest for SWMF and lowest for OpenGGCM. The OpenGGCM tail currents differ significantly from BATS-R-US and SWMF; (2) A longer preconditioning time allowed the magnetosphere to relax more, giving different positions for the magnetopause with all three models before the IMF Bz reversal. There were differences greater than 100% for all three models before the IMF Bz reversal. The differences in the current sheet region for the OpenGGCM were small after the IMF Bz reversal. The BATS-R-US and SWMF differences decreased after the IMF Bz reversal to near zero; (3) For extreme conditions in the solar wind, the OpenGGCM has a large region of Earthward flow velocity (Ux) in the current sheet region that grows as time progresses in a compressed environment. BATS-R-US Bz , rho and Ux stabilize to a near constant value approximately one hour into the run under high compression conditions. Under high compression, the SWMF parameters begin to oscillate approximately 100 minutes into the run. All three models have similar magnetopause positions under low pressure conditions. The OpenGGCM current sheet velocities along the Sun-Earth line are largest under low pressure conditions. The results of this analysis indicate the need for accounting for model uncertainties and differences when comparing model predictions with data, provide error bars on model prediction in various magnetospheric regions, and show that the magnetotail is sensitive to the preconditioning time.

Long-term magnetic activity in close binary systems. I. Patterns of color variations

NASA Astrophysics Data System (ADS)

Messina, S.

2008-03-01

Aims:This is the first of a series of papers in which we present the results of a long-term photometric monitoring project carried out at Catania Astrophysical Observatory aimed at studying magnetic activity in late-type components of close binary systems, its dependence on global stellar parameters, and its evolution on different time scales from days to years. In this first paper, we present the complete observation dataset and new results of an investigation into the origin of brightness and color variations observed in the well-known magnetically active close binary stars: AR Psc, VY Ari, UX Ari, V711 Tau, EI Eri, V1149 Ori, DH Leo, HU Vir, RS CVn, V775 Her, AR Lac, SZ Psc, II Peg and BY Dra Methods: About 38 000 high-precision photoelectric nightly observations in the U, B and V filters are analysed. Correlation and regression analyses of the V magnitude vs. U-B and B-V color variations are carried out and a comparison with model variations for a grid of active region temperature and filling factor values is also performed. Results: We find the existence of two different patterns of color variation. Eight stars in our sample: BY Dra, VY Ari, V775 Her, II Peg, V1149 Ori, HU Vir, EI Eri and DH Leo become redder when they become fainter, as is expected from the presence of active regions consisting of cool spots. The other six stars show the opposite behaviour, i.e. they become bluer when they become fainter. For V711 Tau this behaviour could be explained by the increased relative U- and B-flux contribution by the earlier-type component of the binary system when the cooler component becomes fainter. On the other hand, for AR Psc, UX Ari, RS CVn, SZ Psc and AR Lac the existence of hot photospheric faculae must be invoked. We also found that in single-lined and double-lined binary stars in which the fainter component is inactive or much less active the V magnitude is correlated to B-V and U-B color variations in more than 60% of observation seasons. The correlation is found in less than 40% of observation seasons when the fainter component has a non-negligible level of activity and/or hot faculae are present but they are either spatially or temporally uncorrelated to spots. I dedicate this paper to the memory of the P.I. of this project, Prof. Marcello Rodonò, who suddenly passed away on October 23, 2005. To him my sincere estimation and deepest gratitude. Based on observations collected at INAF-Catania Astrophysical Observatory, Italy.

Leucocytozoon Diversity and Possible Vectors in the Neotropical highlands of Colombia.

PubMed

Lotta, Ingrid A; Pacheco, M Andreína; Escalante, Ananias A; González, Angie D; Mantilla, Juan S; Moncada, Ligia I; Adler, Peter H; Matta, Nubia E

2016-04-01

Studies of the lowland avifauna in the Neotropical Region have shown a paucity of Leucocytozoon species. However, surveys conducted in the Colombian highlands revealed a great diversity of these parasites infecting resident birds. To further investigate the relationship between Leucocytozoon diversity, the potential vectors, and altitudinal distribution, birds from 41 families were sampled at low and high elevations in Colombia. Blood samples were screened by microscopy, and a fragment of cytochrome b was amplified from Leucocytozoon-positive samples. The complete mitochondrial genome was also obtained for each morphospecies of Leucocytozoon. Leucocytozoon species were detected in resident birds, with various degrees of host specificity, at elevations from 2,400 to 3,950 meters above sea level, where five new host-parasite associations were discovered. Phylogenetic analysis based on the cytochrome b fragment suggested that two nominal taxa, L. fringillinarum and L. majoris, are species complexes. Blood sources of Simuliidae revealed generalist-feeding habits that included avian and mammalian hosts. Molecular analysis of parasites in black flies indicated a close relationship with the parasites found in birds. Our investigation provides further evidence that the distribution and transmission of Leucocytozoon species in the Neotropics are influenced by elevation, with the highest prevalence between 2,400 and 3,200 m asl. Copyright © 2016 Elsevier GmbH. All rights reserved.

Spatially extended K Iλ7699 emission in the nebula of VY CMa: kinematics and geometry

NASA Astrophysics Data System (ADS)

Smith, Nathan

2004-04-01

Long-slit echelle spectra reveal bright extended emission from the K Iλ7699 resonance line in the reflection nebula surrounding the extreme red supergiant VY Canis Majoris. The central star has long been known for its unusually bright K I emission lines, but this is the first report of intrinsic emission from K I in the nebula. The extended emission is not just a reflected spectrum of the star, but is due to resonant scattering by K atoms in the outer nebula itself, and is therefore a valuable probe of the kinematics and geometry of the circumstellar environment of VY CMa. Dramatic velocity structure is seen in the long-slit spectra, and most lines of sight through the nebula intersect multiple distinct velocity components. A faint `halo' at large distances from the star does appear to show a reflected spectrum, however, and suggests a systemic velocity of +40 km s-1 with respect to the Sun. The most striking feature is blueshifted emission from the filled interior of a large shell seen in images; the kinematic structure is reminiscent of a Hubble flow, and provides strong evidence for asymmetric and episodic mass loss due to localized eruptions on the stellar surface.

Suggestion for the detection of TiO2 in interstellar medium

NASA Astrophysics Data System (ADS)

Kumar Sharma, Mohit; Sharma, Monika; Chandra, Suresh

2017-09-01

Since all the carbon in oxygen-rich stars is locked into carbon monoxide (CO), how the formation of dust takes place in their environment is a matter of great interest. Being a refractory species, the titanium dioxide (TiO2) is thought to play important role in the dust-condensation sequence. The TiO2 is detected in the environment of red supergiant VY Canis Majoris through sub-millimeter wavelengths. All these lines are between the levels lying at high energies for which large kinetic temperature in the region is required. Based on the detailed study of transfer of radiation, we propose for the identification of TiO2 through its transitions between low lying levels. Using spectroscopic data, we have calculated energies of 100 rotational levels of para-TiO2 (up to 82 cm^{-1}) and the Einstein A-coefficients for radiative transitions between the levels. These Einstein A-coefficients along with the scaled values of collisional rate coefficients, we have solved a set of 100 statistical equilibrium equations coupled with 436 equations of radiative transfer. We have found 9 transitions having anomalous absorption and 6 transitions showing emission features. These transitions may help in identification of TiO2 in a cosmic object.

VY Canis Majoris: Observational Studies of the Outflow

NASA Astrophysics Data System (ADS)

Harwit, M.

2001-12-01

A number of recent studies carried out with the Infrared Space Observatory, ISO, and the Submillimeter Wave Astronomy Satellite, SWAS, provide new information on the chemical composition of the dust and the geometry of the outflow. With ISO, we have obtained a near-, mid-, and far-infrared spectrum of VY CMa that shows the strong preponderance of amorphous, as contrasted to crystalline, silicates. The sharp spectral slope in the near-infrared suggests the presence also of iron grains. While an excellent theoretical fit to the data is obtained, we emphasize that this is far from unique. A resolution of ambiguities will require a self-consistent model that considers not only radiative transfer, but also plausible elemental abundances, laboratory studies of chemical condensation sequences, and gas dynamics. With SWAS we have obtained a high-resolution spectrum of the 557GHz ground state transition of ortho-water. The spectral profile enables us to rule out a number of outflow geometries proposed in the literature. With ISO we also obtained the intensities and velocity structure of several other spectral lines of water. Most of these lines must be optically thick but effectively thin, a circumstance that permits us to make use of recent gas-dynamic models to locate the radial position in the outflow where individual lines are emitted.