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Sample records for ab rr lyrae

  1. NONLINEAR ASTEROSEISMOLOGY OF RR LYRAE

    Energy Technology Data Exchange (ETDEWEB)

    Molnar, L.; Kollath, Z.; Szabo, R. [Konkoly Observatory, MTA CSFK, H-1121 Budapest, Konkoly Thege Miklos ut 15-17 (Hungary); Bryson, S.; Mullally, F.; Thompson, S. E. [NASA Ames Research Center, MS 244-30, Moffet Field, CA 94035 (United States); Kolenberg, K., E-mail: molnar.laszlo@csfk.mta.hu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138 (United States)

    2012-09-20

    The observations of the Kepler Space Telescope revealed that fundamental-mode RR Lyrae stars may show various radial overtones. The presence of multiple radial modes may allow us to conduct nonlinear asteroseismology: comparison of mode amplitudes and frequency shifts between observations and models. Here we report the detection of three radial modes in the star RR Lyr, the eponym of the class, using the Kepler short cadence data: besides the fundamental mode, both the first and the ninth overtones can be derived from the data set. RR Lyrae shows period doubling, but switches occasionally to a state where a pattern of six pulsation cycles repeats instead of two. We found hydrodynamic models that show the same three modes and the period-six state, allowing for comparison with the observations.

  2. First Kepler Results on RR Lyrae Stars

    DEFF Research Database (Denmark)

    Kolenberg, K.; Szabó, R.; Kurtz, D. W.

    2010-01-01

    We present the first results of our analyses of selected RR Lyrae stars for which data have been obtained by the Kepler Mission. As expected, we find a significant fraction of the RRab stars to show the Blazhko effect, a still unexplained phenomenon that manifests itself as periodic amplitude...... and phase modulations of the light curve, on timescales of typically tens to hundreds of days. The long time span of the Kepler Mission of 3.5 yr and the unprecedentedly high precision of its data provide a unique opportunity for the study of RR Lyrae stars. Using data of a modulated star observed...... in the first roll as a showcase, we discuss the data, our analyses, findings, and their implications for our understanding of RR Lyrae stars and the Blazhko effect. With at least 40% of the RR Lyrae stars in our sample showing modulation, we confirm the high incidence rate that was only found in recent high...

  3. RR Lyrae Stars in M4

    Directory of Open Access Journals (Sweden)

    Kuehn Charles A

    2017-01-01

    Full Text Available Observations by Kepler/K2 have revolutionized the study of RR Lyrae stars by allowing the detection of new phenomna, such as low amplitude additional modes and period doubling, which had not previously been seen from the ground. During campaign 2, K2 observed the globular cluster M4, providiing the first opportunity to study a sizeable group of RR Lyrae stars that belong to a single population; the other RR Lyrae stars that have been observed from space are field stars in the galactic halo and thus belong to an assortment of populations. In this poster we present the results of our study of the RR Lyrae variables in M4 from K2 photometry. We have identified additional, low amplitude pulsation modes in both observed RRc stars. In 3 RRab stars we have found the Blazhko effect with periods of 16.6d, 22.4d, and 44.5d.

  4. Unmixing the Galactic Halo with RR Lyrae tagging

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    Belokurov, V.; Deason, A. J.; Koposov, S. E.; Catelan, M.; Erkal, D.; Drake, A. J.; Evans, N. W.

    2018-03-01

    We show that tagging RR Lyrae stars according to their location in the period-amplitude diagram can be used to shed light on the genesis of the Galactic stellar halo. The mixture of RR Lyrae of ab type, separated into classes along the lines suggested by Oosterhoff, displays a strong and coherent evolution with Galactocentric radius. The change in the RR Lyrae composition appears to coincide with the break in the halo's radial density profile at ˜25 kpc. Using simple models of the stellar halo, we establish that at least three different types of accretion events are necessary to explain the observed RRab behavior. Given that there exists a correlation between the RRab class fraction and the total stellar content of a dwarf satellite, we hypothesize that the field halo RRab composition is controlled by the mass of the progenitor contributing the bulk of the stellar debris at the given radius. This idea is tested against a suite of cosmological zoom-in simulations of Milky Way-like stellar halo formation. Finally, we study some of the most prominent stellar streams in the Milky Way halo and demonstrate that their RRab class fractions follow the trends established previously.

  5. RR Lyrae star distance scale and kinematics from inner bulge to 50 kpc

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    Dambis Andrei

    2017-01-01

    Full Text Available We use the currently most complete sample of ∼ 3500 type ab RR Lyraes in our Galaxy with available radial-velocity and [Fe/H] measurements to perform a statisticalparallax analysis for a subsample of ∼ 600 type ab RR Lyraes located within 5 kpc from the Sun to refine the parameters of optical and WISE W1-band period-metallicityluminosity relations and adjust our preliminary distances. The new zero point implies the rescaled estimates for the solar Galactocentric distance (RG = 7.99 ± 0.37 kpc and the LMC distance modulus (DMLMC = 18.39 ±0.09. We use the kinematic data for the entire sample to explore the dependence of the halo and thick-disk RR Lyrae velocity ellipsoids on Galactocentric distance from the inner bulge out to R ∼ 50 kpc.

  6. Gauging the Helium Abundance of the Galactic Bulge RR Lyrae Stars

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    Marconi, Marcella; Minniti, Dante

    2018-02-01

    We report the first estimate of the He abundance of the population of RR Lyrae stars in the Galactic bulge. This is done by comparing the recent observational data with the latest models. We use the large samples of ab-type RR Lyrae stars found by OGLE IV in the inner bulge and by the VVV survey in the outer bulge. We present the result from the new models computed by Marconi et al., showing that the minimum period for fundamental RR Lyrae pulsators depends on the He content. By comparing these models with the observations in a period versus effective temperature plane, we find that the bulk of the bulge ab-type RR Lyrae are consistent with primordial He abundance Y = 0.245, ruling out a significant He-enriched population. This work demonstrates that the He content of the bulge RR Lyrae is different from that of the bulk of the bulge population as traced by the red clump giants that appear to be significantly more He-rich. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes 179.B-2002 and 298.D-5048.

  7. Contamination of RR Lyrae stars from Binary Evolution Pulsators

    Science.gov (United States)

    Karczmarek, Paulina; Pietrzyński, Grzegorz; Belczyński, Krzysztof; Stępień, Kazimierz; Wiktorowicz, Grzegorz; Iłkiewicz, Krystian

    2016-06-01

    Binary Evolution Pulsator (BEP) is an extremely low-mass member of a binary system, which pulsates as a result of a former mass transfer to its companion. BEP mimics RR Lyrae-type pulsations but has different internal structure and evolution history. We present possible evolution channels to produce BEPs, and evaluate the contamination value, i.e. how many objects classified as RR Lyrae stars can be undetected BEPs. In this analysis we use population synthesis code StarTrack.

  8. Gauging the Galactic thick disk with RR Lyrae stars

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    Cruz G.

    2012-02-01

    Full Text Available In this contribution we present results from the QUEST RR Lyrae Survey of the thick disk. The survey spans ~480 sq. deg. at low latitude |b| < 30°, with multi-epoch VRI observations, obtained with the QUEST-I camera at the 1m Jürgen Stock Schmidt telescope located at the National Astronomical Observatory of Venezuela. This constitutes the first deep RR Lyrae survey of the Galactic thick disk conducted at low galactic latitudes, covering simultaneously a large range in radial (8RR Lyrae stars having accurate distances (errors <7% and individual reddenings derived from each star’s color curve at minimum light. Moreover, the use of RR Lyrae stars as tracers ensures negligible contamination from the Galactic thin disk. We find a thick disk mean scale height hZ = 0.94 ± 0.11kpc and scale length hR = 3.2 ± 0.4kpc, derived from the vertical and radial mean density profiles of RR Lyrae stars. We also find evidence of thick disk flaring and results that may suggest the thick disk radial density profile shows signs of antitruncation. We discuss our findings in the context of recent thick disk formation models.

  9. Period Changes of 23 Field RR Lyrae Stars

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    Soo-Chang Rey

    1994-12-01

    Full Text Available The secular period behavior of 23 field RR Lyrae stars is studied in order to determine if the observed period changes could be attributed, at least in the mean, to stellar evolution. The sample of stars is subdivided into two Oosterhoff groups based on the metallicity and period-shift. Despite the small sample size, we found a distinct bias toward positive period changes in the group variables. The period changes of the group variables in globular clusters. This provides yet another support for the Lee, Demarque, and Zinn(1990 evolutionary models of RR Lyrae stars and their explanation of the Sandage period-shift effect.

  10. Characterization of the VVV Survey RR Lyrae Population across the Southern Galactic Plane

    Energy Technology Data Exchange (ETDEWEB)

    Minniti, Dante; Palma, Tali; Pullen, Joyce; Tissera, Patricia [Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andrés Bello, Av. Fernández Concha 700, Las Condes, Santiago (Chile); Dékány, Istvan [Astronomisches Rechen-Institut, Zentrum fuer Astronomie der Universitaet Heidelberg, Moenchhofstr. 12-14, D-69120 Heidelberg (Germany); Majaess, Daniel [Mount Saint Vincent University, Halifax, Nova Scotia (Canada); Rejkuba, Marina; Valenti, Elena [European Southern Observatory, Karl-Schwarszchild-Str. 2, D-85748 Garching bei Muenchen (Germany); Alonso-García, Javier; Catelan, Marcio; Contreras Ramos, Rodrigo; Zoccali, Manuela [Instituto Milenio de Astrofísica, Santiago (Chile); Gonzalez, Oscar A. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom); Hempel, Maren [Pontificia Universidad Católica de Chile, Instituto de Astrofisica, Av. Vicuna Mackenna 4860, Santiago (Chile); Irwin, Mike [Institute of Astronomy, Cambridge University, Cambridge, CB3 0HA (United Kingdom); Lucas, Philip W. [Department of Astronomy, University of Hertfordshire, Hertfordshire (United Kingdom); Saito, Roberto K. [Departamento de Física, Universidade Federal de Santa Catarina, Trindade 88040-900, Florianópolis, SC (Brazil)

    2017-04-01

    Deep near-IR images from the VISTA Variables in the Vía Láctea (VVV) Survey were used to search for RR Lyrae stars in the Southern Galactic plane. A sizable sample of 404 RR Lyrae of type ab stars was identified across a thin slice of the fourth Galactic quadrant (295° < ℓ < 350°, −2.°24 < b < −1.°05). The sample’s distance distribution exhibits a maximum density that occurs at the bulge tangent point, which implies that this primarily Oosterhoff type I population of RRab stars does not trace the bar delineated by their red clump counterparts. The bulge RR Lyrae population does not extend beyond ℓ  ∼ 340°, and the sample’s spatial distribution presents evidence of density enhancements and substructure that warrants further investigation. Indeed, the sample may be employed to evaluate Galactic evolution models, and is particularly lucrative since half of the discovered RR Lyrae are within reach of Gaia astrometric observations.

  11. RR LYRAE ATMOSPHERICS: WRINKLES OLD AND NEW. A PREVIEW

    International Nuclear Information System (INIS)

    Preston, George W.

    2011-01-01

    I report some results of an echelle spectroscopic survey of RR Lyrae stars begun in 2006 that I presented in my Henry Norris Lecture of 2010 January 4. Topics include (1) atmospheric velocity gradients, (2) phase-dependent envelope turbulence as it relates to Peterson's discoveries of axial rotation on the horizontal branch and to Stothers' explanation of the Blazhko effect, (3) the three apparitions of hydrogen emission during a pulsation cycle, (4) the occurrence of He I lines in emission and absorption, (5) detection of He II emission and metallic line doubling in Blazhko stars, and finally (6) speculation about what helium observations of RR Lyrae stars in omega Centauri might tell us about the putative helium populations and the horizontal branch of that strange globular cluster.

  12. Absolute Magnitudes and Colors of RR Lyrae Stars in DECam Passbands from Photometry of the Globular Cluster M5

    Science.gov (United States)

    Vivas, A. Katherina; Saha, Abhijit; Olsen, Knut; Blum, Robert; Olszewski, Edward W.; Claver, Jennifer; Valdes, Francisco; Axelrod, Tim; Kaleida, Catherine; Kunder, Andrea; Narayan, Gautham; Matheson, Thomas; Walker, Alistair

    2017-09-01

    We characterize the absolute magnitudes and colors of RR Lyrae stars in the globular cluster M5 in the ugriz filter system of the Dark Energy Camera (DECam). We provide empirical period-luminosity (P-L) relationships in all five bands based on 47 RR Lyrae stars of the type ab and 14 stars of the type c. The P-L relationships were found to be better constrained for the fundamental-mode RR Lyrae stars in the riz passbands, with dispersions of 0.03, 0.02 and 0.02 mag, respectively. The dispersion of the color at minimum light was found to be small, supporting the use of this parameter as a means to obtain accurate interstellar extinctions along the line of sight up to the distance of the RR Lyrae star. We found a trend of color at minimum light with a pulsational period that, if taken into account, brings the dispersion in color at minimum light to ≤slant 0.016 mag for the (r-I), (I-z), and (r-z) colors. These calibrations will be very useful for using RR Lyrae stars from DECam observations as both standard candles for distance determinations and color standards for reddening measurements.

  13. Reddening and blanketing of RR-Lyrae stars, ch. 3

    International Nuclear Information System (INIS)

    Lub, J.

    1977-01-01

    The effects of metal line blanketing and interstellar reddening upon the colours of the RR-Lyrae Stars are discussed. Due to the faintness of these stars in the ultraviolet W channel (at lambda 3720 A) the photometry is in most cases reduced to a four-colour VBLU photometry, i.e. there are only three colour indices available for the determination of the four quantities: interstellar reddening, effective temperature, atmospheric pressure (or effective gravity), and metal line strength which determine the energy distribution that was measured

  14. Extended Aperture Photometry of K2 RR Lyrae stars

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    Plachy, Emese; Klagyivik, Péter; Molnár, László; Sódor, Ádám; Szabó, Róbert

    2017-10-01

    We present the method of the Extended Aperture Photometry (EAP) that we applied on K2 RR Lyrae stars. Our aim is to minimize the instrumental variations of attitude control maneuvers by using apertures that cover the positional changes in the field of view thus contain the stars during the whole observation. We present example light curves that we compared to the light curves from the K2 Systematics Correction (K2SC) pipeline applied on the automated Single Aperture Photometry (SAP) and on the Pre-search Data Conditioning Simple Aperture Photometry (PDCSAP) data.

  15. Extended Aperture Photometry of K2 RR Lyrae stars

    Directory of Open Access Journals (Sweden)

    Plachy Emese

    2017-01-01

    Full Text Available We present the method of the Extended Aperture Photometry (EAP that we applied on K2 RR Lyrae stars. Our aim is to minimize the instrumental variations of attitude control maneuvers by using apertures that cover the positional changes in the field of view thus contain the stars during the whole observation. We present example light curves that we compared to the light curves from the K2 Systematics Correction (K2SC pipeline applied on the automated Single Aperture Photometry (SAP and on the Pre-search Data Conditioning Simple Aperture Photometry (PDCSAP data.

  16. An Update on the Status of RR Lyrae Research - Report of the RRL2015 Meeting (October, Hungary) (Abstract)

    Science.gov (United States)

    Kolenberg, K.

    2016-06-01

    (Abstract only) In October 2015 we organized the first international meeting focused on RR Lyrae research, with the goal to discuss recent developments and future RR Lyrae plans. The Scientific rationale is the following:

  17. THE HORIZONTAL BRANCH OF NGC 1851: CONSTRAINTS FROM ITS RR LYRAE VARIABLES

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    Kunder, Andrea; De Propris, Roberto; Walker, Alistair [NOAO-Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Salaris, Maurizio [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom); Cassisi, Santi [INAF-Osservatorio Astronomico di Collurania, Via M. Maggini, I-64100 Teramo (Italy); Stetson, Peter B. [Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council, Victoria, BC (Canada); Catelan, Marcio; Amigo, Pia, E-mail: akunder@ctio.noao.edu, E-mail: mcatelan@astro.puc.cl [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago (Chile)

    2013-01-01

    We use the pulsational properties of the RR Lyrae variables in the globular cluster NGC 1851 to obtain detailed constraints of the various sub-stellar populations present along its horizontal branch. On the basis of detailed synthetic horizontal branch modeling, we find that minor helium variations (Y {approx} 0.248-0.280) are able to reproduce the observed periods and amplitudes of the RR Lyrae variables, as well as the frequency of fundamental and first-overtone RR Lyrae stars. Comparison of number ratios among the blue and red horizontal branch components and the two observed subgiant branches also suggest that the RR Lyrae variables originated from the progeny of the bright subgiant branch. The RR Lyrae variables with slightly enhanced helium (Y {approx} 0.270-0.280) have longer periods at a given amplitude, as is seen with Oosterhoff II (OoII) RR Lyrae variables, whereas the RR Lyrae variables with Y {approx} 0.248-0.270 have shorter periods, exhibiting properties of Oosterhoff I (OoI) variables. This correlation does suggest that the pulsational properties of RR Lyrae stars can be very useful for tracing the various subpopulations and can provide suitable constraints on the multiple population phenomenon. It appears to be of great interest to explore whether this conclusion can be generalized to other globular clusters hosting multiple populations.

  18. Anatomy of the Orphan Stream using RR Lyrae Stars

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    Hendel, David; Johnston, Kathryn; Scowcroft, Victoria; SMHASH

    2018-01-01

    Stellar tidal streams provide an opportunity to study the motion and structure of the disrupting galaxy as well as the gravitational potential of its host. Streams around the Milky Way are especially promising as new datasets make additional phase space dimensions available as constraints. We present observations of 32 stars thought to be RR Lyrae in the Orphan tidal stream as part of the {\\it Spitzer} Merger History and Shape of the Galactic Halo (SMHASH) program. The extremely tight correlation between the periods, luminosities, and metallicities of RR Lyrae variable stars in the {\\it Spitzer} IRAC $3.6\\mu$m band allows the determination of precise distances to individual stars; the median statistical distance uncertainty in this sample is $2.5\\%$. By fitting orbits in an example potential we obtain an upper limit on the mass of the Milky Way interior to 60 kpc of $\\mathrm{3.9_{-0.8}^{+1.2}\\times 10^{11} M_\\odot}$, bringing estimates based on the Orphan stream in line with those using other tracers. The SMHASH data also resolves the stream in line-of-sight depth, allowing unprecedented access its internal structure. Comparing this structure with n-body models we find that Orphan had an initial dark halo mass $\\sim \\mathrm{3 \\times 10^{9} M_\\odot}$, placing the progenitor amongst the classical dwarf spheriodals.

  19. RR Lyrae in LMC Globular Clusters: Insights into the Oosterhoff Phenomenon and Milky Way Formation

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    Kuehn, Charles A., III; Smith, H. A.; Catelan, M.; Taylor, L.; McClellan, R. E.; Looper, K.; DeLee, N.; Pritzl, B. J.

    2011-01-01

    We present results from a study of RR Lyrae stars in five globular clusters located in the Large Magellanic Cloud. The goal of this study was to look at the behavior and properties of RR Lyrae stars in Oosterhoff-intermediate globular clusters and compare them to RR Lyrae in Oosterhoff I and II clusters. New BVI photometric observations of these clusters were obtained with the SMARTS consortium telescopes and with the SOAR 4-meter telescope. We present light curves and Fourier properties for the RR Lyrae stars in our study as well as physical properties for these stars derived from their Fourier parameters. We compare these physical properties to those of RR Lyrae in Milky Way halo globular clusters and discuss implications for Milky Way halo formation.

  20. Variable stars in Leo A : RR Lyrae stars, short-period cepheids, and implications for stellar content

    NARCIS (Netherlands)

    Dolphin, AE; Saha, A; Claver, J; Skillman, ED; Cole, AA; Gallagher, JS; Tolstoy, E; Dohm-Palmer, RC; Mateo, M

    We present the results of a search for short-period variable stars in Leo A. We have found 92 candidate variables, including eight candidate RR Lyrae stars. From the RR Lyrae stars, we measure a distance modulus of (m - M)(0) = 24.51 +/- 0.12, or 0.80 +/- 0.04 Mpc. This discovery of RR Lyrae stars

  1. THE RR LYRAE VARIABLES AND HORIZONTAL BRANCH OF NGC 6656 (M22) {sup ,}

    Energy Technology Data Exchange (ETDEWEB)

    Kunder, Andrea; Walker, Alistair R.; Paredes Alvarez, Leonardo [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Stetson, Peter B. [Dominion Astrophysical Observatory, NRC-Herzberg, National Research Council, Victoria BC, V9E 2E7 (Canada); Cassisi, Santi [INAF-Osservatorio Astronomico di Collurania, Via M. Maggini, I-64100 Teramo (Italy); Layden, Andrew [Bowling Green State University, Bowling Green, OH 43403 (United States); Bono, Giuseppe [Dipartimento di Fisica, Universita di Roma Tor Vergata, Rome (Italy); Catelan, Márcio [Pontificia Universidad Católica de Chile, Departamento de Astronomía y Astrofísica, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago (Chile); Clem, James L. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States); Matsunaga, Noriyuki [Department of Astronomy, School of Science, The University of Tokyo (Japan); Salaris, Maurizio [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom); Lee, Jae-Woo [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Chaboyer, Brian, E-mail: akunder@ctio.noao.edu, E-mail: mcatelan@astro.puc.cl [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)

    2013-11-01

    The first calibrated broadband UBVI time-series photometry is presented for the RR Lyrae variable stars in NGC 6656 (M22), with observations spanning a range of 22 years. We have also redetermined the variability types and periods for the RR Lyrae stars identified previously by photographic observations, revising the number of fundamental-mode RR Lyrae variables (RR0) to 10 and the number of first-overtone variables (RR1) to 16. The mean periods of the RR0 and RR1 variables are (P) {sub RR0} = 0.66 ± 0.02 days and (P) {sub RR1} = 0.33 ± 0.01 days, respectively, supporting an Oosterhoff II classification for the cluster. The number ratio of RR1-type to all RR-type variables is N {sub 1}/N{sub RR} = 0.61, also consistent with an Oosterhoff II designation. Both the RR Lyrae stars' minimum light colors and the blue edge of the RR Lyrae instability strip suggest E( B – – V) = 0.36 ± 0.02 mag toward M22. Regarding the HB morphology of M22, we find (B-R)/(B+V+R) = +0.97 ± 0.1 and at least one ''gap'' located in an unusual part of the blue HB, in the middle of the so-called hot HB stars.

  2. Fourteen candidate RR Lyrae star streams in the inner Galaxy

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    Mateu, Cecilia; Read, Justin I.; Kawata, Daisuke

    2018-03-01

    We apply the GC3 stream-finding method to RR Lyrae stars (RRLSs) in the Catalina survey. We find 2 RRLS stream candidates at >4σ confidence and another 12 at >3.5σ confidence over the Galactocentric distance range 4 < D/kpc < 26. Of these, only two are associated with known globular clusters (NGC 1261 and Arp2). The remainder are candidate `orphan' streams, consistent with the idea that globular cluster streams are most visible close to dissolution. Our detections are likely a lower bound on the total number of dissolving globulars in the inner galaxy, since many globulars have few RRLSs, while only the brightest streams are visible over the Galactic RRLS background, particularly given the current lack of kinematical information. We make all of our candidate streams publicly available and provide a new galstreamsPYTHON library for the footprints of all known streams and overdensities in the Milky Way.

  3. Recent progress in the theoretical modelling of Cepheids and RR Lyrae stars

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    Marconi, Marcella

    2017-09-01

    Cepheids and RR Lyrae are among the most important primary distance indicators to calibrate the extragalactic distance ladder and excellent stellar population tracers, for Population I and Population II, respectively. In this paper I first mention some recent theoretical studies of Cepheids and RR Lyrae obtained with different theoretical tools. Then I focus the attention on new results based on nonlinear convective pulsation models in the context of some international projects, including VMC@VISTA and the Gaia collaboration. The open problems for both Cepheids and RR Lyrae are briefly discussed together with some challenging future application.

  4. DISTANCE SCALE ZERO POINTS FROM GALACTIC RR LYRAE STAR PARALLAXES

    International Nuclear Information System (INIS)

    We present new absolute trigonometric parallaxes and proper motions for seven Population II variable stars—five RR Lyr variables: RZ Cep, XZ Cyg, SU Dra, RR Lyr, and UV Oct; and two type 2 Cepheids: VY Pyx and κ Pav. We obtained these results with astrometric data from Fine Guidance Sensors, white-light interferometers on Hubble Space Telescope. We find absolute parallaxes in milliseconds of arc: RZ Cep, 2.12 ± 0.16 mas; XZ Cyg, 1.67 ± 0.17 mas; SU Dra, 1.42 ± 0.16 mas; RR Lyr, 3.77 ± 0.13 mas; UV Oct, 1.71 ± 0.10 mas; VY Pyx, 6.44 ± 0.23 mas; and κ Pav, 5.57 ± 0.28 mas; an average σ π /π = 5.4%. With these parallaxes, we compute absolute magnitudes in V and K bandpasses corrected for interstellar extinction and Lutz-Kelker-Hanson bias. Using these RR Lyrae variable star absolute magnitudes, we then derive zero points for M V -[Fe/H] and M K -[Fe/H]-log P relations. The technique of reduced parallaxes corroborates these results. We employ our new results to determine distances and ages of several Galactic globular clusters and the distance of the Large Magellanic Cloud. The latter is close to that previously derived from Classical Cepheids uncorrected for any metallicity effect, indicating that any such effect is small. We also discuss the somewhat puzzling results obtained for our two type 2 Cepheids.

  5. DISCOVERY OF RR LYRAE STARS IN THE NUCLEAR BULGE OF THE MILKY WAY

    Energy Technology Data Exchange (ETDEWEB)

    Minniti, Dante; Ramos, Rodrigo Contreras; Zoccali, Manuela; Gran, Felipe [Instituto Milenio de Astrofisica, Santiago (Chile); Rejkuba, Marina; Valenti, Elena [European Southern Observatory, Karl-Schwarszchild-Str. 2, D-85748 Garching bei Muenchen (Germany); Gonzalez, Oscar A., E-mail: dante@astrofisica.cl, E-mail: rcontrer@astro.puc.cl [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)

    2016-10-10

    Galactic nuclei, such as that of the Milky Way, are extreme regions with high stellar densities, and in most cases, the hosts of a supermassive black hole. One of the scenarios proposed for the formation of the Galactic nucleus is merging of primordial globular clusters. An implication of this model is that this region should host stars that are characteristically found in old Milky Way globular clusters. RR Lyrae stars are primary distance indicators, well known representatives of old and metal-poor stellar populations, and therefore are regularly found in globular clusters. Here we report the discovery of a dozen RR Lyrae type ab stars in the vicinity of the Galactic center, i.e., in the so-called nuclear stellar bulge of the Milky Way. This discovery provides the first direct observational evidence that the Galactic nuclear stellar bulge contains ancient stars (>10 Gyr old). Based on this we conclude that merging globular clusters likely contributed to the build-up of the high stellar density in the nuclear stellar bulge of the Milky Way.

  6. The VMC survey - XXVI. Structure of the Small Magellanic Cloud from RR Lyrae stars

    Science.gov (United States)

    Muraveva, T.; Subramanian, S.; Clementini, G.; Cioni, M.-R. L.; Palmer, M.; van Loon, J. Th.; Moretti, M. I.; de Grijs, R.; Molinaro, R.; Ripepi, V.; Marconi, M.; Emerson, J.; Ivanov, V. D.

    2018-01-01

    We present results from the analysis of 2997 fundamental mode RR Lyrae variables located in the Small Magellanic Cloud (SMC). For these objects, near-infrared time series photometry from the VISTA survey of the Magellanic Clouds system (VMC) and visual light curves from the OGLE IV (Optical Gravitational Lensing Experiment IV) survey are available. In this study, the multi-epoch Ks-band VMC photometry was used for the first time to derive intensity-averaged magnitudes of the SMC RR Lyrae stars. We determined individual distances to the RR Lyrae stars from the near-infrared period-absolute magnitude-metallicity (PM_{K_s}Z) relation, which has some advantages in comparison with the visual absolute magnitude-metallicity (MV-[Fe/H]) relation, such as a smaller dependence of the luminosity on interstellar extinction, evolutionary effects and metallicity. The distances we have obtained were used to study the three-dimensional structure of the SMC. The distribution of the SMC RR Lyrae stars is found to be ellipsoidal. The actual line-of-sight depth of the SMC is in the range 1-10 kpc, with an average depth of 4.3 ± 1.0 kpc. We found that RR Lyrae stars in the eastern part of the SMC are affected by interactions of the Magellanic Clouds. However, we do not see a clear bimodality observed for red clump stars, in the distribution of RR Lyrae stars.

  7. Imbalanced Learning for RR Lyrae Stars Based on SDSS and GALEX Databases

    Science.gov (United States)

    Zhang, Jingyi; Zhang, Yanxia; Zhao, Yongheng

    2018-03-01

    We apply machine learning and Convex-Hull algorithms to separate RR Lyrae stars from other stars like main-sequence stars, white dwarf stars, carbon stars, CVs, and carbon-lines stars, based on the Sloan Digital Sky Survey and Galaxy Evolution Explorer (GALEX). In low-dimensional spaces, the Convex-Hull algorithm is applied to select RR Lyrae stars. Given different input patterns of (u ‑ g, g ‑ r), (g ‑ r, r ‑ i), (r ‑ i, i ‑ z), (u ‑ g, g ‑ r, r ‑ i), (g ‑ r, r ‑ i, i ‑ z), (u ‑ g, g ‑ r, i ‑ z), and (u ‑ g, r ‑ i, i ‑ z), different convex hulls can be built for RR Lyrae stars. Comparing the performance of different input patterns, u ‑ g, g ‑ r, i ‑ z is the best input pattern. For this input pattern, the efficiency (the fraction of true RR Lyrae stars in the predicted RR Lyrae sample) is 4.2% with a completeness (the fraction of recovered RR Lyrae stars in the whole RR Lyrae sample) of 100%, increases to 9.9% with 97% completeness and to 16.1% with 53% completeness by removing some outliers. In high-dimensional spaces, machine learning algorithms are used with input patterns (u ‑ g, g ‑ r, r ‑ i, i ‑ z), (u ‑ g, g ‑ r, r ‑ i, i ‑ z, r), (NUV ‑ u, u ‑ g, g ‑ r, r ‑ i, i ‑ z), and (NUV ‑ u, u ‑ g, g ‑ r, r ‑ i, i ‑ z, r). RR Lyrae stars, which belong to the class of interest in our paper, are rare compared to other stars. For the highly imbalanced data, cost-sensitive Support Vector Machine, cost-sensitive Random Forest, and Fast Boxes is used. The results show that information from GALEX is helpful for identifying RR Lyrae stars, and Fast Boxes is the best performer on the skewed data in our case.

  8. VizieR Online Data Catalog: Mid-infrared study of RR Lyrae stars (Gavrilchenko+, 2014)

    Science.gov (United States)

    Gavrilchenko, T.; Klein, C. R.; Bloom, J. S.; Richards, J. W.

    2015-02-01

    The first goal was to find a large sample of WISE-observed RR Lyrae stars. A data base of previously identified RR Lyrae stars was created, combining information from General Catalogue of Variable Stars (GCVS), All Sky Automated Survey (ASAS), SIMBAD, VizieR, and individual papers. For many of the sources in this data base the only available data were the coordinates and RR Lyrae classification. When provided, information about the period, distance, subclass, and magnitude for several different wavebands was also stored. If a single source appeared in multiple surveys or papers, information from all relevant surveys was included, with markers indicating contradicting measurements between surveys. The resulting data base contains about 17000 sources, of which about 5000 sources have documented V-band periods. (3 data files).

  9. Discovery of Distant RR Lyrae Stars in the Milky Way Using DECam

    Science.gov (United States)

    Medina, Gustavo E.; Muñoz, Ricardo R.; Vivas, A. Katherina; Carlin, Jeffrey L.; Förster, Francisco; Martínez, Jorge; Galbany, Lluís; González-Gaitán, Santiago; Hamuy, Mario; de Jaeger, Thomas; Maureira, Juan Carlos; San Martín, Jaime

    2018-03-01

    We report the discovery of distant RR Lyrae stars, including the most distant known in the Milky Way, using data taken in the g-band with the Dark Energy Camera as part of the High cadence Transient Survey (HiTS; 2014 campaign). We detect a total of 173 RR Lyrae stars over a ∼120 deg2 area, including both known RR Lyrae and new detections. The heliocentric distances d H of the full sample range from 9 to >200 kpc, with 18 of them beyond 90 kpc. We identify three sub-groups of RR Lyrae as members of known systems: the Sextans dwarf spheroidal galaxy, for which we report 46 new discoveries, and the ultra-faint dwarf galaxies Leo IV and Leo V. Following an MCMC methodology, we fit spherical and ellipsoidal profiles of the form ρ(R) ∼ R n to the radial density distribution of RR Lyrae in the Galactic halo. The best fit corresponds to the spherical case, for which we obtain a simple power-law index of n=-{4.17}-0.20+0.18, consistent with recent studies made with samples covering shorter distances. The pulsational properties of the outermost RR Lyrae in the sample (d H > 90 kpc) differ from the ones in the halo population at closer distances. The distribution of the stars in a period-amplitude diagram suggest they belong to Oosterhoff-intermediate or Oosterhoff II groups, similar to what is found in the ultra-faint dwarf satellites around the Milky Way. The new distant stars discovered represent an important addition to the few existing tracers of the Milky Way potential in the outer halo.

  10. Does Kepler unveil the mystery of the Blazhko effect? First detection of period doubling in Kepler Blazhko RR Lyrae stars

    DEFF Research Database (Denmark)

    Szabó, R.; Kollath, Z.; Molnár, L.

    2010-01-01

    -doubling bifurcation in our non-linear RR Lyrae models computed by the Florida-Budapest hydrocode. This enabled us to trace the origin of this instability in RR Lyrae stars to a resonance, namely a 9:2 resonance between the fundamental mode and a high-order (ninth) radial overtone showing strange-mode characteristics...

  11. Gaia's Cepheids and RR Lyrae stars and luminosity calibrations based on Tycho-Gaia Astrometric Solution

    Science.gov (United States)

    Clementini, Gisella; Eyer, Laurent; Muraveva, Tatiana; Garofalo, Alessia; Ripepi, Vincenzo; Marconi, Marcella; Sarro, Luis; Palmer, Max; Luri, Xavier; Molinaro, Roberto; Rimoldini, Lorenzo; Szabados, Laszlo; Anderson, Richard I.; Musella, Ilaria

    2017-09-01

    Gaia Data Release 1 contains parallaxes for more than 700 Galactic Cepheids and RR Lyrae stars, computed as part of the Tycho-Gaia Astrometric Solution (TGAS). We have used TGAS parallaxes, along with literature (V, I, J, Ks, W1) photometry and spectroscopy, to calibrate the zero point of the period-luminosity and period-Wesenheit relations of classical and type II Cepheids, and the near-infrared period-luminosity, period-luminosity-metallicity and optical luminosity-metallicity relations of RR Lyrae stars. In this contribution we briefly summarise results obtained by fitting these basic relations adopting different techniques that operate either in parallax or distance (absolute magnitude) space.

  12. A HIGH-VELOCITY BULGE RR LYRAE VARIABLE ON A HALO-LIKE ORBIT

    International Nuclear Information System (INIS)

    Kunder, Andrea; Storm, J.; Rich, R. M.; Hawkins, K.; Poleski, R.; Johnson, C. I.; Shen, J.; Li, Z.-Y.; Cordero, M. J.; Nataf, D. M.; Bono, G.; Walker, A. R.; Koch, A.; De Propris, R.; Udalski, A.; Szymanski, M. K.; Soszynski, I.; Pietrzynski, G.; Ulaczyk, K.; Wyrzykowski, Ł.

    2015-01-01

    We report on the RR Lyrae variable star, MACHO 176.18833.411, located toward the Galactic bulge and observed within the data from the ongoing Bulge RR Lyrae Radial Velocity Assay, which has the unusual radial velocity of −372 ± 8 km s −1 and true space velocity of −482 ± 22 km s −1 relative to the Galactic rest frame. Located less than 1 kpc from the Galactic center and toward a field at (l, b) = (3, −2.5), this pulsating star has properties suggesting it belongs to the bulge RR Lyrae star population, yet a velocity indicating it is abnormal, at least with respect to bulge giants and red clump stars. We show that this star is most likely a halo interloper and therefore suggest that halo contamination is not insignificant when studying metal-poor stars found within the bulge area, even for stars within 1 kpc of the Galactic center. We discuss the possibility that MACHO 176.18833.411 is on the extreme edge of the bulge RR Lyrae radial velocity distribution, and also consider a more exotic scenario in which it is a runaway star moving through the Galaxy

  13. Abundance of Chemical Elements in RR Lyrae Variables and their Kinematic Parameters

    Science.gov (United States)

    Gozha, M. L.; Marsakov, V. A.; Koval', V. V.

    2018-03-01

    A catalog of the chemical and spatial-kinematic parameters of 415 RR Lyrae variables (Lyrids) in the galactic field is compiled. Spectroscopic determinations of the relative abundances of 13 chemical elements in 101 of the RR Lyrae variables are collected from 25 papers published between 1995 and 2017. The data from different sources are reduced to a single solar abundance scale. The mean weighted chemical abundances are calculated with coefficients inversely proportional to the reported errors. An analysis of the deviations in the published relative abundances in each star from the mean square values calculated from them reveals an absence of systematic biases among the results from the various articles. The rectangular coordinates of 407 of the RR Lyrae variables and the components of the three-dimensional (3D) velocities of 401 of the stars are calculated using data from several sources. The collected data on the abundances of chemical elements produced by various nuclear fusion processes for the RR Lyrae variables of the field, as well as the calculated 3D velocities, can be used for studying the evolution of the Galaxy.

  14. A HIGH-VELOCITY BULGE RR LYRAE VARIABLE ON A HALO-LIKE ORBIT

    Energy Technology Data Exchange (ETDEWEB)

    Kunder, Andrea; Storm, J. [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Rich, R. M. [Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, CA 90095-1562 (United States); Hawkins, K. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Poleski, R. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Johnson, C. I. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Shen, J.; Li, Z.-Y. [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Cordero, M. J. [Astronomisches Rechen-Institut: Zentrum für Astronomie, Mönchhofstr. 12-14, D-69120 Heidelberg (Germany); Nataf, D. M. [Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611 (Australia); Bono, G. [Dipartimento di Fisica, Universita di Roma Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Roma (Italy); Walker, A. R. [Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena (Chile); Koch, A. [Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Königstuhl 12, D-69117 Heidelberg (Germany); De Propris, R. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Turku (Finland); Udalski, A.; Szymanski, M. K.; Soszynski, I.; Pietrzynski, G.; Ulaczyk, K.; Wyrzykowski, Ł. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); and others

    2015-07-20

    We report on the RR Lyrae variable star, MACHO 176.18833.411, located toward the Galactic bulge and observed within the data from the ongoing Bulge RR Lyrae Radial Velocity Assay, which has the unusual radial velocity of −372 ± 8 km s{sup −1} and true space velocity of −482 ± 22 km s{sup −1} relative to the Galactic rest frame. Located less than 1 kpc from the Galactic center and toward a field at (l, b) = (3, −2.5), this pulsating star has properties suggesting it belongs to the bulge RR Lyrae star population, yet a velocity indicating it is abnormal, at least with respect to bulge giants and red clump stars. We show that this star is most likely a halo interloper and therefore suggest that halo contamination is not insignificant when studying metal-poor stars found within the bulge area, even for stars within 1 kpc of the Galactic center. We discuss the possibility that MACHO 176.18833.411 is on the extreme edge of the bulge RR Lyrae radial velocity distribution, and also consider a more exotic scenario in which it is a runaway star moving through the Galaxy.

  15. THE DETERMINATION OF REDDENING FROM INTRINSIC VR COLORS OF RR LYRAE STARS

    International Nuclear Information System (INIS)

    Kunder, Andrea; Chaboyer, Brian; Layden, Andrew

    2010-01-01

    New R-band observations of 21 local field RR Lyrae variable stars are used to explore the reliability of minimum light (V - R) colors as a tool for measuring interstellar reddening. For each star, R-band intensity mean magnitudes and light amplitudes are presented. Corresponding V-band light curves from the literature are supplemented with the new photometry, and (V - R) colors at minimum light are determined for a subset of these stars as well as for other stars in the literature. Two different definitions of minimum light color are examined, one which uses a Fourier decomposition to the V and R light curves to find (V - R) at minimum V-band light, (V - R) F min , and the other which uses the average color between the phase interval 0.5-0.8, (V - R) φ(0.5-0.8) min . From 31 stars with a wide range of metallicities and pulsation periods, the mean dereddened RR Lyrae color at minimum light is (V - R) F min,0 = 0.28 ± 0.02 mag and (V - R) φ(0.5-0.8) min,0 = 0.27 ± 0.02 mag. As was found by Guldenschuh et al. using (V - I) colors, any dependence of the star's minimum light color on metallicity or pulsation amplitude is too weak to be formally detected. We find that the intrinsic (V - R) of Galactic bulge RR Lyrae stars are similar to those found by their local counterparts and hence that bulge RR0 Lyrae stars do not have anomalous colors as compared to the local RR Lyrae stars.

  16. Mapping the Tidal Destruction of the Hercules Dwarf: A Wide-field DECam Imaging Search for RR Lyrae Stars

    Science.gov (United States)

    Garling, Christopher; Willman, Beth; Sand, David J.; Hargis, Jonathan; Crnojević, Denija; Bechtol, Keith; Carlin, Jeffrey L.; Strader, Jay; Zou, Hu; Zhou, Xu; Nie, Jundan; Zhang, Tianmeng; Zhou, Zhimin; Peng, Xiyan

    2018-01-01

    We investigate the hypothesized tidal disruption of the Hercules ultra-faint dwarf galaxy (UFD). Previous tidal disruption studies of the Hercules UFD have been hindered by the high degree of foreground contamination in the direction of the dwarf. We bypass this issue by using RR Lyrae stars, which are standard candles with a very low field-volume density at the distance of Hercules. We use wide-field imaging from the Dark Energy Camera on CTIO to identify candidate RR Lyrae stars, supplemented with observations taken in coordination with the Beijing–Arizona Sky Survey on the Bok Telescope. Combining color, magnitude, and light-curve information, we identify three new RR Lyrae stars associated with Hercules. All three of these new RR Lyrae stars lie outside its published tidal radius. When considered with the nine RR Lyrae stars already known within the tidal radius, these results suggest that a substantial fraction of Hercules’ stellar content has been stripped. With this degree of tidal disruption, Hercules is an interesting case between a visibly disrupted dwarf (such as the Sagittarius dwarf spheroidal galaxy) and one in dynamic equilibrium. The degree of disruption also shows that we must be more careful with the ways we determine object membership when estimating dwarf masses in the future. One of the three discovered RR Lyrae stars sits along the minor axis of Hercules, but over two tidal radii away. This type of debris is consistent with recent models that suggest Hercules’ orbit is aligned with its minor axis.

  17. The space photometry revolution and our understanding of RR Lyrae stars

    Directory of Open Access Journals (Sweden)

    Szabó R.

    2015-01-01

    Full Text Available The study of RR Lyrae stars has recently been invigorated thanks to the long, uninterrupted, ultra-precise time series data provided by the Kepler and CoRoT space telescopes. We give a brief overview of the new observational findings concentrating on the connection between period doubling and the Blazhko modulation, and the omnipresence of additional periodicities in all RR Lyrae subtypes, except for non-modulated RRab stars. Recent theoretical results demonstrate that if more than two modes are present in a nonlinear dynamical system such as a high-amplitude RR Lyrae star, the outcome is often an extremely intricate dynamical state. Thus, based on these discoveries, an underlying picture of complex dynamical interactions between modes is emerging which sheds new light on the century-old Blazhko-phenomenon, as well. New directions of theoretical efforts, like multidimensional hydrodynamical simulations, future space photometric missions and detailed spectroscopic investigations will pave the way towards a more complete understanding of the atmospheric and pulsation dynamics of these enigmatic touchstone objects.

  18. Gaia Data Release 1. Testing parallaxes with local Cepheids and RR Lyrae stars

    Science.gov (United States)

    Gaia Collaboration; Clementini, G.; Eyer, L.; Ripepi, V.; Marconi, M.; Muraveva, T.; Garofalo, A.; Sarro, L. M.; Palmer, M.; Luri, X.; Molinaro, R.; Rimoldini, L.; Szabados, L.; Musella, I.; Anderson, R. I.; Prusti, T.; de Bruijne, J. H. J.; Brown, A. G. A.; Vallenari, A.; Babusiaux, C.; Bailer-Jones, C. A. L.; Bastian, U.; Biermann, M.; Evans, D. W.; Jansen, F.; Jordi, C.; Klioner, S. A.; Lammers, U.; Lindegren, L.; Mignard, F.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; Valette, V.; van Leeuwen, F.; Walton, N. A.; Aerts, C.; Arenou, F.; Cropper, M.; Drimmel, R.; Høg, E.; Katz, D.; Lattanzi, M. G.; O'Mullane, W.; Grebel, E. K.; Holland, A. D.; Huc, C.; Passot, X.; Perryman, M.; Bramante, L.; Cacciari, C.; Castañeda, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Hernández, J.; Jean-Antoine-Piccolo, A.; Masana, E.; Messineo, R.; Mowlavi, N.; Nienartowicz, K.; Ordóñez-Blanco, D.; Panuzzo, P.; Portell, J.; Richards, P. J.; Riello, M.; Seabroke, G. M.; Tanga, P.; Thévenin, F.; Torra, J.; Els, S. G.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Lock, T.; Mercier, E.; Altmann, M.; Andrae, R.; Astraatmadja, T. L.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Busso, G.; Carry, B.; Cellino, A.; Cowell, S.; Creevey, O.; Cuypers, J.; Davidson, M.; De Ridder, J.; de Torres, A.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Frémat, Y.; García-Torres, M.; Gosset, E.; Halbwachs, J.-L.; Hambly, N. C.; Harrison, D. L.; Hauser, M.; Hestroffer, D.; Hodgkin, S. T.; Huckle, H. E.; Hutton, A.; Jasniewicz, G.; Jordan, S.; Kontizas, M.; Korn, A. J.; Lanzafame, A. C.; Manteiga, M.; Moitinho, A.; Muinonen, K.; Osinde, J.; Pancino, E.; Pauwels, T.; Petit, J.-M.; Recio-Blanco, A.; Robin, A. C.; Siopis, C.; Smith, M.; Smith, K. W.; Sozzetti, A.; Thuillot, W.; van Reeven, W.; Viala, Y.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Aguado, J. J.; Allan, P. M.; Allasia, W.; Altavilla, G.; Álvarez, M. A.; Alves, J.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Antoja, T.; Antón, S.; Arcay, B.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Barache, C.; Barata, C.; Barbier, A.; Barblan, F.; Barrado y Navascués, D.; Barros, M.; Barstow, M. A.; Becciani, U.; Bellazzini, M.; Bello García, A.; Belokurov, V.; Bendjoya, P.; Berihuete, A.; Bianchi, L.; Bienaymé, O.; Billebaud, F.; Blagorodnova, N.; Blanco-Cuaresma, S.; Boch, T.; Bombrun, A.; Borrachero, R.; Bouquillon, S.; Bourda, G.; Bragaglia, A.; Breddels, M. A.; Brouillet, N.; Brüsemeister, T.; Bucciarelli, B.; Burgess, P.; Burgon, R.; Burlacu, A.; Busonero, D.; Buzzi, R.; Caffau, E.; Cambras, J.; Campbell, H.; Cancelliere, R.; Cantat-Gaudin, T.; Carlucci, T.; Carrasco, J. M.; Castellani, M.; Charlot, P.; Charnas, J.; Chiavassa, A.; Clotet, M.; Cocozza, G.; Collins, R. S.; Costigan, G.; Crifo, F.; Cross, N. J. G.; Crosta, M.; Crowley, C.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; De Cat, P.; de Felice, F.; de Laverny, P.; De Luise, F.; De March, R.; de Souza, R.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; Di Matteo, P.; Diakite, S.; Distefano, E.; Dolding, C.; Dos Anjos, S.; Drazinos, P.; Durán, J.; Dzigan, Y.; Edvardsson, B.; Enke, H.; Evans, N. W.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Falcão, A. J.; Farràs Casas, M.; Federici, L.; Fedorets, G.; Fernández-Hernández, J.; Fernique, P.; Fienga, A.; Figueras, F.; Filippi, F.; Findeisen, K.; Fonti, A.; Fouesneau, M.; Fraile, E.; Fraser, M.; Fuchs, J.; Gai, M.; Galleti, S.; Galluccio, L.; Garabato, D.; García-Sedano, F.; Garralda, N.; Gavras, P.; Gerssen, J.; Geyer, R.; Gilmore, G.; Girona, S.; Giuffrida, G.; Gomes, M.; González-Marcos, A.; González-Núñez, J.; González-Vidal, J. J.; Granvik, M.; Guerrier, A.; Guillout, P.; Guiraud, J.; Gúrpide, A.; Gutiérrez-Sánchez, R.; Guy, L. P.; Haigron, R.; Hatzidimitriou, D.; Haywood, M.; Heiter, U.; Helmi, A.; Hobbs, D.; Hofmann, W.; Holl, B.; Holland, G.; Hunt, J. A. S.; Hypki, A.; Icardi, V.; Irwin, M.; Jevardat de Fombelle, G.; Jofré, P.; Jonker, P. G.; Jorissen, A.; Julbe, F.; Karampelas, A.; Kochoska, A.; Kohley, R.; Kolenberg, K.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Koubsky, P.; Krone-Martins, A.; Kudryashova, M.; Bachchan, R. K.; Lacoste-Seris, F.; Lanza, A. F.; Lavigne, J.-B.; Le Poncin-Lafitte, C.; Lebreton, Y.; Lebzelter, T.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lemaitre, V.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; Löffler, W.; López, M.; Lorenz, D.; MacDonald, I.; Magalhães Fernandes, T.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchal, O.; Marchant, J. M.; Marinoni, S.; Marrese, P. M.; Marschalkó, G.; Marshall, D. J.; Martín-Fleitas, J. M.; Martino, M.; Mary, N.; Matijevič, G.; McMillan, P. J.; Messina, S.; Michalik, D.; Millar, N. R.; Miranda, B. M. H.; Molina, D.; Molinaro, M.; Molnár, L.; Moniez, M.; Montegriffo, P.; Mor, R.; Mora, A.; Morbidelli, R.; Morel, T.; Morgenthaler, S.; Morris, D.; Mulone, A. F.; Narbonne, J.; Nelemans, G.; Nicastro, L.; Noval, L.; Ordénovic, C.; Ordieres-Meré, J.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Parsons, P.; Pecoraro, M.; Pedrosa, R.; Pentikäinen, H.; Pichon, B.; Piersimoni, A. M.; Pineau, F.-X.; Plachy, E.; Plum, G.; Poujoulet, E.; Prša, A.; Pulone, L.; Ragaini, S.; Rago, S.; Rambaux, N.; Ramos-Lerate, M.; Ranalli, P.; Rauw, G.; Read, A.; Regibo, S.; Reylé, C.; Ribeiro, R. A.; Riva, A.; Rixon, G.; Roelens, M.; Romero-Gómez, M.; Rowell, N.; Royer, F.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sarasso, M.; Savietto, H.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Segransan, D.; Shih, I.-C.; Smareglia, R.; Smart, R. L.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Süveges, M.; Surdej, J.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Tingley, B.; Trager, S. C.; Turon, C.; Ulla, A.; Utrilla, E.; Valentini, G.; van Elteren, A.; Van Hemelryck, E.; van Leeuwen, M.; Varadi, M.; Vecchiato, A.; Veljanoski, J.; Via, T.; Vicente, D.; Vogt, S.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Weingrill, K.; Wevers, T.; Wyrzykowski, Ł.; Yoldas, A.; Žerjal, M.; Zucker, S.; Zurbach, C.; Zwitter, T.; Alecu, A.; Allen, M.; Allende Prieto, C.; Amorim, A.; Anglada-Escudé, G.; Arsenijevic, V.; Azaz, S.; Balm, P.; Beck, M.; Bernstein, H.-H.; Bigot, L.; Bijaoui, A.; Blasco, C.; Bonfigli, M.; Bono, G.; Boudreault, S.; Bressan, A.; Brown, S.; Brunet, P.-M.; Bunclark, P.; Buonanno, R.; Butkevich, A. G.; Carret, C.; Carrion, C.; Chemin, L.; Chéreau, F.; Corcione, L.; Darmigny, E.; de Boer, K. S.; de Teodoro, P.; de Zeeuw, P. T.; Delle Luche, C.; Domingues, C. D.; Dubath, P.; Fodor, F.; Frézouls, B.; Fries, A.; Fustes, D.; Fyfe, D.; Gallardo, E.; Gallegos, J.; Gardiol, D.; Gebran, M.; Gomboc, A.; Gómez, A.; Grux, E.; Gueguen, A.; Heyrovsky, A.; Hoar, J.; Iannicola, G.; Isasi Parache, Y.; Janotto, A.-M.; Joliet, E.; Jonckheere, A.; Keil, R.; Kim, D.-W.; Klagyivik, P.; Klar, J.; Knude, J.; Kochukhov, O.; Kolka, I.; Kos, J.; Kutka, A.; Lainey, V.; LeBouquin, D.; Liu, C.; Loreggia, D.; Makarov, V. V.; Marseille, M. G.; Martayan, C.; Martinez-Rubi, O.; Massart, B.; Meynadier, F.; Mignot, S.; Munari, U.; Nguyen, A.-T.; Nordlander, T.; O'Flaherty, K. S.; Ocvirk, P.; Olias Sanz, A.; Ortiz, P.; Osorio, J.; Oszkiewicz, D.; Ouzounis, A.; Park, P.; Pasquato, E.; Peltzer, C.; Peralta, J.; Péturaud, F.; Pieniluoma, T.; Pigozzi, E.; Poels, J.; Prat, G.; Prod'homme, T.; Raison, F.; Rebordao, J. M.; Risquez, D.; Rocca-Volmerange, B.; Rosen, S.; Ruiz-Fuertes, M. I.; Russo, F.; Serraller Vizcaino, I.; Short, A.; Siebert, A.; Silva, H.; Sinachopoulos, D.; Slezak, E.; Soffel, M.; Sosnowska, D.; Straižys, V.; ter Linden, M.; Terrell, D.; Theil, S.; Tiede, C.; Troisi, L.; Tsalmantza, P.; Tur, D.; Vaccari, M.; Vachier, F.; Valles, P.; Van Hamme, W.; Veltz, L.; Virtanen, J.; Wallut, J.-M.; Wichmann, R.; Wilkinson, M. I.; Ziaeepour, H.; Zschocke, S.

    2017-09-01

    Context. Parallaxes for 331 classical Cepheids, 31 Type II Cepheids, and 364 RR Lyrae stars in common between Gaia and the Hipparcos and Tycho-2 catalogues are published in Gaia Data Release 1 (DR1) as part of the Tycho-Gaia Astrometric Solution (TGAS). Aims: In order to test these first parallax measurements of the primary standard candles of the cosmological distance ladder, which involve astrometry collected by Gaia during the initial 14 months of science operation, we compared them with literature estimates and derived new period-luminosity (PL), period-Wesenheit (PW) relations for classical and Type II Cepheids and infrared PL, PL-metallicity (PLZ), and optical luminosity-metallicity (MV-[Fe/H]) relations for the RR Lyrae stars, with zero points based on TGAS. Methods: Classical Cepheids were carefully selected in order to discard known or suspected binary systems. The final sample comprises 102 fundamental mode pulsators with periods ranging from 1.68 to 51.66 days (of which 33 with σϖ/ϖType II Cepheids include a total of 26 W Virginis and BL Herculis stars spanning the period range from 1.16 to 30.00 days (of which only 7 with σϖ/ϖcomputed using multi-band (V,I,J,Ks) photometry and spectroscopic metal abundances available in the literature, and by applying three alternative approaches: (I) linear least-squares fitting of the absolute magnitudes inferred from direct transformation of the TGAS parallaxes; (II) adopting astrometry-based luminosities; and (III) using a Bayesian fitting approach. The last two methods work in parallax space where parallaxes are used directly, thus maintaining symmetrical errors and allowing negative parallaxes to be used. The TGAS-based PL,PW,PLZ, and MV- [Fe/H] relations are discussed by comparing the distance to the Large Magellanic Cloud provided by different types of pulsating stars and alternative fitting methods. Results: Good agreement is found from direct comparison of the parallaxes of RR Lyrae stars for which both

  19. PROBING THE OUTER GALACTIC HALO WITH RR LYRAE FROM THE CATALINA SURVEYS

    Energy Technology Data Exchange (ETDEWEB)

    Drake, A. J.; Djorgovski, S. G.; Graham, M. J.; Mahabal, A.; Donalek, C.; Williams, R. [Department of Astronomy and the Center for Advanced Computing Research, California Institute of Technology, 1200 East California Boulevard, CA 91225 (United States); Catelan, M.; Torrealba, G. [Departamento de Astronomia y Astrofisica, Facultad de Fisica, Pontificia Universidad Catolica de Chile, Av. Vicuna Mackena 4860, 782-0436 Macul, Santiago (Chile); Belokurov, V.; Koposov, S. E. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Prieto, J. L. [Department of Astronomy, Princeton University, 4 Ivy Ln, Princeton, NJ 08544 (United States); Larson, S.; Christensen, E.; Beshore, E. [Department of Planetary Sciences, Lunar and Planetary Laboratory, The University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States)

    2013-01-20

    We present analysis of 12,227 type-ab RR Lyraes (RRLs) found among the 200 million public light curves in Catalina Surveys Data Release 1. These stars span the largest volume of the Milky Way ever surveyed with RRLs, covering {approx}20,000 deg{sup 2} of the sky (0 Degree-Sign < {alpha} < 360 Degree-Sign , -22 Degree-Sign < {delta} < 65 Degree-Sign ) to heliocentric distances of up to 60 kpc. Each of the RRLs is observed between 60 and 419 times over a six-year period. Using period finding and Fourier fitting techniques we determine periods and apparent magnitudes for each source. We find that the periods are generally accurate to {sigma} = 0.002% in comparison to 2842 previously known RRLs and 100 RRLs observed in overlapping survey fields. We photometrically calibrate the light curves using 445 Landolt standard stars and show that the resulting magnitudes are accurate to {approx}0.05 mag using Sloan Digital Sky Survey (SDSS) data for {approx}1000 blue horizontal branch stars and 7788 RRLs. By combining Catalina photometry with SDSS spectroscopy, we analyze the radial velocity and metallicity distributions for >1500 of the RRLs. Using the accurate distances derived for the RRLs, we show the paths of the Sagittarius tidal streams crossing the sky at heliocentric distances from 20 to 60 kpc. By selecting samples of Galactic halo RRLs, we compare their velocity, metallicity, and distance with predictions from a recent detailed N-body model of the Sagittarius system. We find that there are some significant differences between the distances and structures predicted and our observations.

  20. Modelling the nucleosynthetic properties of carbon-enhanced metal-poor RR Lyrae stars

    OpenAIRE

    Stancliffe, Richard J.; Kennedy, Catherine R.; Lau, Herbert H. B.; Beers, Timothy C.

    2013-01-01

    Certain carbon-enhanced metal-poor stars likely obtained their composition via pollution from some of the earliest generations of asymptotic giant branch stars and as such provide important clues to early Universe nucleosynthesis. Recently, Kinman et al. discovered that the highly carbon- and barium-enriched metal-poor star SDSS J1707+58 is in fact an RR Lyrae pulsator. This gives us an object in a definite evolutionary state where the effects of dilution of material during the Main Sequence ...

  1. The Blazhko Effect and Additional Excited Modes in RR Lyrae Stars

    Science.gov (United States)

    Benkő, J. M.; Szabó, R.

    2015-08-01

    Recent photometric space missions, such as CoRoT and Kepler, revealed that many RR Lyrae stars pulsate—beyond their main radial pulsation mode—in low-amplitude modes. Space data seem to indicate a clear trend that, namely, overtone (RRc) stars and modulated fundamental (RRab) RR Lyrae stars ubiquitously show additional modes, while non-Blazhko RRab stars never do. Two Kepler stars (V350 Lyr and KIC 7021124), however, apparently seemed to break this rule: they were classified as non-Blazhko RRab stars showing additional modes. We processed Kepler pixel photometric data of these stars. We detected a small amplitude (but significant) Blazhko effect for both stars by using the resulting light curves and O-C diagrams. This finding strengthens the apparent connection between the Blazhko effect and the excitation of additional modes. In addition, it yields a potential tool for detecting Blazhko stars through the additional frequency patterns, even if we have only short but accurate time series observations. V350 Lyr shows the smallest amplitude multiperiodic Blazhko effect ever detected.

  2. Modelling the nucleosynthetic properties of carbon-enhanced metal-poor RR Lyrae stars

    Science.gov (United States)

    Stancliffe, Richard J.; Kennedy, Catherine R.; Lau, Herbert H. B.; Beers, Timothy C.

    2013-10-01

    Certain carbon-enhanced metal-poor stars likely obtained their composition via pollution from some of the earliest generations of asymptotic giant branch stars and as such provide important clues to early Universe nucleosynthesis. Recently, Kinman et al. discovered that the highly carbon- and barium-enriched metal-poor star SDSS J1707+58 is in fact an RR Lyrae pulsator. This gives us an object in a definite evolutionary state where the effects of dilution of material during the main sequence are minimized owing to the object having passed through first dredge-up. We perform detailed stellar modelling of putative progenitor systems in which we accreted material from asymptotic giant branch stars in the mass range 1-2 M⊙. We investigate how the surface abundances are affected by the inclusion of mechanisms like thermohaline mixing and gravitational settling. While we are able to find a reasonable fit to the carbon and sodium abundances of SDSS J1707+58, suggesting accretion of around 0.1 M⊙ from a 2 M⊙ companion, the strontium and barium abundances remain problematic and this object may have experienced something other than a standard s-process. We have more success in fitting the abundances of the mildly carbon-enriched, metal-poor RR Lyrae pulsator TY Gru (CS 22881-071), which we suggest received 0.1 M⊙ of material from a companion of around 1 M⊙.

  3. TRACING THE ORPHAN STREAM TO 55 kpc WITH RR LYRAE STARS

    Energy Technology Data Exchange (ETDEWEB)

    Sesar, Branimir; Cohen, Judith G.; Bellm, Eric C.; Levitan, David; Tang, Sumin; Waszczak, Adam; Kulkarni, Shrinivas R.; Prince, Thomas A. [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Grillmair, Carl J.; Laher, Russ R.; Surace, Jason A. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Bhalerao, Varun B. [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007 (India); Ofek, Eran O., E-mail: bsesar@astro.caltech.edu [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel)

    2013-10-10

    We report positions, velocities, and metallicities of 50 ab-type RR Lyrae (RRab) stars observed in the vicinity of the Orphan stellar stream. Using about 30 RRab stars classified as being likely members of the Orphan stream, we study the metallicity and the spatial extent of the stream. We find that RRab stars in the Orphan stream have a wide range of metallicities, from –1.5 dex to –2.7 dex. The average metallicity of the stream is –2.1 dex, identical to the value obtained by Newberg et al. using blue horizontal branch stars. We find that the most distant parts of the stream (40-50 kpc from the Sun) are about 0.3 dex more metal-poor than the closer parts (within ∼30 kpc), suggesting a possible metallicity gradient along the stream's length. We have extended the previous studies and have mapped the stream up to 55 kpc from the Sun. Even after a careful search, we did not identify any more distant RRab stars that could plausibly be members of the Orphan stream. If confirmed with other tracers, this result would indicate a detection of the end of the leading arm of the stream. We have compared the distances of Orphan stream RRab stars with the best-fit orbits obtained by Newberg et al. We find that model 6 of Newberg et al. cannot explain the distances of the most remote Orphan stream RRab stars, and conclude that the best fit to distances of Orphan stream RRab stars and to the local circular velocity is provided by potentials where the total mass of the Galaxy within 60 kpc is M{sub 60} ∼ 2.7 × 10{sup 11} M{sub ☉}, or about 60% of the mass found by previous studies. More extensive modeling that would consider non-spherical potentials and the possibility of misalignment between the stream and the orbit is highly encouraged.

  4. Machine-learned Identification of RR Lyrae Stars from Sparse, Multi-band Data: The PS1 Sample

    Science.gov (United States)

    Sesar, Branimir; Hernitschek, Nina; Mitrović, Sandra; Ivezić, Željko; Rix, Hans-Walter; Cohen, Judith G.; Bernard, Edouard J.; Grebel, Eva K.; Martin, Nicolas F.; Schlafly, Edward F.; Burgett, William S.; Draper, Peter W.; Flewelling, Heather; Kaiser, Nick; Kudritzki, Rolf P.; Magnier, Eugene A.; Metcalfe, Nigel; Tonry, John L.; Waters, Christopher

    2017-05-01

    RR Lyrae stars may be the best practical tracers of Galactic halo (sub-)structure and kinematics. The PanSTARRS1 (PS1) 3π survey offers multi-band, multi-epoch, precise photometry across much of the sky, but a robust identification of RR Lyrae stars in this data set poses a challenge, given PS1's sparse, asynchronous multi-band light curves (≲ 12 epochs in each of five bands, taken over a 4.5 year period). We present a novel template fitting technique that uses well-defined and physically motivated multi-band light curves of RR Lyrae stars, and demonstrate that we get accurate period estimates, precise to 2 s in > 80 % of cases. We augment these light-curve fits with other features from photometric time-series and provide them to progressively more detailed machine-learned classification models. From these models, we are able to select the widest (three-fourths of the sky) and deepest (reaching 120 kpc) sample of RR Lyrae stars to date. The PS1 sample of ˜45,000 RRab stars is pure (90%) and complete (80% at 80 kpc) at high galactic latitudes. It also provides distances that are precise to 3%, measured with newly derived period-luminosity relations for optical/near-infrared PS1 bands. With the addition of proper motions from Gaia and radial velocity measurements from multi-object spectroscopic surveys, we expect the PS1 sample of RR Lyrae stars to become the premier source for studying the structure, kinematics, and the gravitational potential of the Galactic halo. The techniques presented in this study should translate well to other sparse, multi-band data sets, such as those produced by the Dark Energy Survey and the upcoming Large Synoptic Survey Telescope Galactic plane sub-survey.

  5. The occurrence of binary evolution pulsators in classical instability strip of RR Lyrae and Cepheid variables

    Science.gov (United States)

    Karczmarek, P.; Wiktorowicz, G.; Iłkiewicz, K.; Smolec, R.; Stępień, K.; Pietrzyński, G.; Gieren, W.; Belczynski, K.

    2017-04-01

    Single star evolution does not allow extremely low-mass stars to cross the classical instability strip (IS) during the Hubble time. However, within binary evolution framework low-mass stars can appear inside the IS once the mass transfer (MT) is taken into account. Triggered by a discovery of low-mass (0.26 M⊙) RR Lyrae-like variable in a binary system, OGLE-BLG-RRLYR-02792, we investigate the occurrence of similar binary components in the IS, which set up a new class of low-mass pulsators. They are referred to as binary evolution pulsators (BEPs) to underline the interaction between components, which is crucial for substantial mass-loss prior to the IS entrance. We simulate a population of 500 000 metal-rich binaries and report that 28 143 components of binary systems experience severe MT (losing up to 90 per cent of mass), followed by at least one IS crossing in luminosity range of RR Lyrae (RRL) or Cepheid variables. A half of these systems enter the IS before the age of 4 Gyr. BEPs display a variety of physical and orbital parameters, with the most important being the BEP mass in range 0.2-0.8 M⊙, and the orbital period in range 10-2 500 d. Based on the light curve only, BEPs can be misclassified as genuine classical pulsators, and as such they would contaminate genuine RRL and classical Cepheid variables at levels of 0.8 and 5 per cent, respectively. We state that the majority of BEPs will remain undetected and we discuss relevant detection limitations.

  6. On the RR Lyrae Stars in Globulars. V. The Complete Near-infrared (JHK s ) Census of ω Centauri RR Lyrae Variables

    Science.gov (United States)

    Braga, V. F.; Stetson, P. B.; Bono, G.; Dall’Ora, M.; Ferraro, I.; Fiorentino, G.; Iannicola, G.; Marconi, M.; Marengo, M.; Monson, A. J.; Neeley, J.; Persson, S. E.; Beaton, R. L.; Buonanno, R.; Calamida, A.; Castellani, M.; Di Carlo, E.; Fabrizio, M.; Freedman, W. L.; Inno, L.; Madore, B. F.; Magurno, D.; Marchetti, E.; Marinoni, S.; Marrese, P.; Matsunaga, N.; Minniti, D.; Monelli, M.; Nonino, M.; Piersimoni, A. M.; Pietrinferni, A.; Prada-Moroni, P.; Pulone, L.; Stellingwerf, R.; Tognelli, E.; Walker, A. R.; Valenti, E.; Zoccali, M.

    2018-03-01

    We present a new complete near-infrared (NIR, JHK s ) census of RR Lyrae stars (RRLs) in the globular ω Cen (NGC 5139). We collected 15,472 JHK s images with 4–8 m class telescopes over 15 years (2000–2015) covering a sky area around the cluster center of 60 × 34 arcmin2. These images provided calibrated photometry for 182 out of the 198 cluster RRL candidates with 10 to 60 measurements per band. We also provide new homogeneous estimates of the photometric amplitude for 180 (J), 176 (H) and 174 (K s ) RRLs. These data were supplemented with single-epoch JK s magnitudes from VHS and with single-epoch H magnitudes from 2MASS. Using proprietary optical and NIR data together with new optical light curves (ASAS-SN) we also updated pulsation periods for 59 candidate RRLs. As a whole, we provide JHK s magnitudes for 90 RRab (fundamentals), 103 RRc (first overtones) and one RRd (mixed-mode pulsator). We found that NIR/optical photometric amplitude ratios increase when moving from first overtone to fundamental and to long-period (P > 0.7 days) fundamental RRLs. Using predicted period–luminosity–metallicity relations, we derive a true distance modulus of 13.674 ± 0.008 ± 0.038 mag (statistical error and standard deviation of the median) based on spectroscopic iron abundances, and of 13.698 ± 0.004 ± 0.048 mag based on photometric iron abundances. We also found evidence of possible systematics at the 5%–10% level in the zero-point of the period–luminosity relations based on the five calibrating RRLs whose parallaxes had been determined with the HST. This publication makes use of data gathered with the Magellan/Baade Telescope at Las Campanas Observatory, the Blanco Telescope at Cerro Tololo Inter-American Observatory, NTT at La Silla (ESO Program IDs: 64.N-0038(A), 66.D-0557(A), 68.D-0545(A), 073.D-0313(A), ID 073.D-0313(A) and 59.A-9004(D)), VISTA at Paranal (ESO Program ID: 179.A-2010) and VLT at Paranal (ESO Program ID: ID96406).

  7. Gaia’s Cepheids and RR Lyrae stars and luminosity calibrations based on Tycho-Gaia Astrometric Solution

    Directory of Open Access Journals (Sweden)

    Clementini Gisella

    2017-01-01

    Full Text Available Gaia Data Release 1 contains parallaxes for more than 700 Galactic Cepheids and RR Lyrae stars, computed as part of the Tycho-Gaia Astrometric Solution (TGAS. We have used TGAS parallaxes, along with literature (V, I, J, Ks, W1 photometry and spectroscopy, to calibrate the zero point of the period-luminosity and period-Wesenheit relations of classical and type II Cepheids, and the near-infrared period-luminosity, period-luminosity-metallicity and optical luminosity-metallicity relations of RR Lyrae stars. In this contribution we briefly summarise results obtained by fitting these basic relations adopting different techniques that operate either in parallax or distance (absolute magnitude space.

  8. The first all-sky view of the Milky Way stellar halo with Gaia+2MASS RR Lyrae

    Science.gov (United States)

    Iorio, G.; Belokurov, V.; Erkal, D.; Koposov, S. E.; Nipoti, C.; Fraternali, F.

    2018-02-01

    We exploit the first Gaia data release to study the properties of the Galactic stellar halo as traced by RR Lyrae. We demonstrate that it is possible to select a pure sample of RR Lyrae using only photometric information available in the Gaia+2MASS catalogue. The final sample contains about 21 600 RR Lyrae covering an unprecedented fraction ( ˜ 60 per cent) of the volume of the Galactic inner halo (R < 28 kpc). We study the morphology of the stellar halo by analysing the RR Lyrae distribution with parametric and non-parametric techniques. Taking advantage of the uniform all-sky coverage, we test halo models more sophisticated than usually considered in the literature, such as those with varying flattening, tilts and/or offset of the halo with respect to the Galactic disc. A consistent picture emerges: the inner halo is well reproduced by a smooth distribution of stars settled on triaxial density ellipsoids. The shortest axis is perpendicular to the Milky Way's disc, while the longest axis forms an angle of ˜70° with the axis connecting the Sun and the Galactic Centre. The elongation along the major axis is mild (p = 1.27), and the vertical flattening is shown to evolve from a squashed state with q ≈ 0.57 in the centre to a more spherical q ≈ 0.75 at the outer edge of our data set. Within the radial range probed, the density profile of the stellar halo is well approximated by a single power law with exponent α = -2.96. We do not find evidence of tilt or offset of the halo with respect to the Galaxy's disc.

  9. VizieR Online Data Catalog: Standard Galactic field RR Lyrae. I. Photometry (Monson+, 2017)

    Science.gov (United States)

    Monson, A. J.; Beaton, R. L.; Scowcroft, V.; Freedman, W. L.; Madore, B. F.; Rich, J. A.; Seibert, M.; Kollmeier, J. A.; Clementini, G.

    2017-06-01

    The Three-hundred MilliMeter Telescope (TMMT) is a fully robotic, 300mm telescope at Las Campanas Observatory (LCO), for which the nightly operation and data processing have been completely automated. Over the course of two years data were collected on 179 individual nights for our sample of the 55 RR Lyrae in the B, V, and IC broadband filters. Of these nights, 76 were under photometric conditions and calibrated directly. The 103 nonphotometric nights were roughly calibrated by using the default transformation equations, but only provide differential photometry relative to the calibrated frames. This resulted in 59698 final individual observations. Individual data points have a typical photometric precision of 0.02mag. The statistical error falls rapidly with hundreds of observations, with the zero-point uncertainties being the largest source of uncertainty in the final reported mean magnitude. To compare the results of our TMMT campaign to previous studies of these RR Lyrae (RRL) and to fill gaps in our TMMT phase coverage, we have compiled available broadband data from literature published over the past 30 years and spanning our full wavelength coverage (0.4 to 4.5μm) from the optical to mid-infrared. We have homogenized these diverse data sets to the following filter systems: Johnson UBV, Kron-Cousins RI, 2MASS J,H,Ks, and Spitzer [3.6], [4.5]. The All Sky Automated Survey (ASAS; http://www.astrouw.edu.pl/asas/) is a long-term project monitoring all stars brighter than V~14mag. The program covers both hemispheres, with telescopes at Las Campanas Observatory in Chile and Haleakala on Maui, both of which provide simultaneous I and V photometry. The GEOS RR Lyr Survey (http://www.ast.obs-mip.fr/users/leborgne/dbRR/grrs.html) is a long-term program utilizing TAROT (http://tarot.obs-hp.fr/) at Calern Observatory (Nice University, France). Annual data releases from this project add times for maximum light for program stars over the last year of observations. In

  10. PERIOD–COLOR AND AMPLITUDE–COLOR RELATIONS AT MAXIMUM AND MINIMUM LIGHT FOR RR LYRAE STARS IN THE SDSS STRIPE 82 REGION

    International Nuclear Information System (INIS)

    Ngeow, Chow-Choong; Kanbur, Shashi M.; Schrecengost, Zachariah; Bhardwaj, Anupam; Singh, Harinder P.

    2017-01-01

    Investigation of period–color (PC) and amplitude–color (AC) relations at the maximum and minimum light can be used to probe the interaction of the hydrogen ionization front (HIF) with the photosphere and the radiation hydrodynamics of the outer envelopes of Cepheids and RR Lyraes. For example, theoretical calculations indicated that such interactions would occur at minimum light for RR Lyrae and result in a flatter PC relation. In the past, the PC and AC relations have been investigated by using either the ( V − R ) MACHO or ( V − I ) colors. In this work, we extend previous work to other bands by analyzing the RR Lyraes in the Sloan Digital Sky Survey Stripe 82 Region. Multi-epoch data are available for RR Lyraes located within the footprint of the Stripe 82 Region in five ( ugriz ) bands. We present the PC and AC relations at maximum and minimum light in four colors: ( u − g ) 0 , ( g − r ) 0 , ( r − i ) 0 , and ( i − z ) 0 , after they are corrected for extinction. We found that the PC and AC relations for this sample of RR Lyraes show a complex nature in the form of flat, linear or quadratic relations. Furthermore, the PC relations at minimum light for fundamental mode RR Lyrae stars are separated according to the Oosterhoff type, especially in the ( g − r ) 0 and ( r − i ) 0 colors. If only considering the results from linear regressions, our results are quantitatively consistent with the theory of HIF-photosphere interaction for both fundamental and first overtone RR Lyraes.

  11. PERIOD–COLOR AND AMPLITUDE–COLOR RELATIONS AT MAXIMUM AND MINIMUM LIGHT FOR RR LYRAE STARS IN THE SDSS STRIPE 82 REGION

    Energy Technology Data Exchange (ETDEWEB)

    Ngeow, Chow-Choong [Graduate Institute of Astronomy, National Central University, Jhongli 32001, Taiwan (China); Kanbur, Shashi M.; Schrecengost, Zachariah [Department of Physics, SUNY Oswego, Oswego, NY 13126 (United States); Bhardwaj, Anupam; Singh, Harinder P. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2017-01-10

    Investigation of period–color (PC) and amplitude–color (AC) relations at the maximum and minimum light can be used to probe the interaction of the hydrogen ionization front (HIF) with the photosphere and the radiation hydrodynamics of the outer envelopes of Cepheids and RR Lyraes. For example, theoretical calculations indicated that such interactions would occur at minimum light for RR Lyrae and result in a flatter PC relation. In the past, the PC and AC relations have been investigated by using either the ( V − R ){sub MACHO} or ( V − I ) colors. In this work, we extend previous work to other bands by analyzing the RR Lyraes in the Sloan Digital Sky Survey Stripe 82 Region. Multi-epoch data are available for RR Lyraes located within the footprint of the Stripe 82 Region in five ( ugriz ) bands. We present the PC and AC relations at maximum and minimum light in four colors: ( u − g ){sub 0}, ( g − r ){sub 0}, ( r − i ){sub 0}, and ( i − z ){sub 0}, after they are corrected for extinction. We found that the PC and AC relations for this sample of RR Lyraes show a complex nature in the form of flat, linear or quadratic relations. Furthermore, the PC relations at minimum light for fundamental mode RR Lyrae stars are separated according to the Oosterhoff type, especially in the ( g − r ){sub 0} and ( r − i ){sub 0} colors. If only considering the results from linear regressions, our results are quantitatively consistent with the theory of HIF-photosphere interaction for both fundamental and first overtone RR Lyraes.

  12. Metal-rich RRc Stars in the Carnegie RR Lyrae Survey

    Science.gov (United States)

    Sneden, Christopher; Preston, George W.; Kollmeier, Juna A.; Crane, Jeffrey D.; Morrell, Nidia; Prieto, José L.; Shectman, Stephen A.; Skowron, Dorota M.; Thompson, Ian B.

    2018-01-01

    We describe and employ a stacking procedure to investigate abundances derived from the low signal-to-noise ratio spectra obtained in the Carnegie RR Lyrae Survey (CARRS). We find iron metallicities that extend from [Fe/H] ∼ ‑2.5 to values at least as large as [Fe/H] ∼ ‑0.5 in the 274-spectrum CARRS RRc data set. We consider RRc sample contamination by high amplitude solar metallicity δ Scuti stars (HADS) at periods less than 0.3 days, where photometric discrimination between RRc and δ Scuti stars has proven to be problematic. We offer a spectroscopic discriminant, the well-marked overabundance of heavy elements, principally [Ba/H], that is a common, if not universal, characteristic of HADS of all periods and axial rotations. No bona fide RRc stars known to us have verified heavy-element overabundances. Three out of 34 stars in our sample with [Fe/H] > ‑0.7 exhibit anomalously strong features of Sr, Y, Zr, Ba, and many rare earths. However, carbon is not enhanced in these three stars, and we conclude that their elevated n-capture abundances have not been generated in interior neutron-capture nucleosynthesis. Contamination by HADS appears to be unimportant, and metal-rich RRc stars occur in approximately the same proportion in the Galactic field as do metal-rich RRab stars. An apparent dearth of metal-rich RRc is probably a statistical fluke. Finally, we show that RRc stars have a similar inverse period–metallicity relationship as has been found for RRab stars.

  13. ON THE RR LYRAE STARS IN GLOBULARS. IV. ω CENTAURI OPTICAL UBVRI PHOTOMETRY

    Energy Technology Data Exchange (ETDEWEB)

    Braga, V. F.; Bono, G.; Buonanno, R. [Department of Physics, Università di Roma Tor Vergata, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Stetson, P. B. [NRC-Herzberg, Dominion Astrophysical Observatory, 5071 West Saanich Road, Victoria BC V9E 2E7 (Canada); Dall’Ora, M. [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); Ferraro, I.; Iannicola, G.; Castellani, M. [INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monte Porzio Catone (Italy); Fiorentino, G. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Freyhammer, L. M. [Jeremiah Horrocks Institute of Astrophysics, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Marengo, M.; Neeley, J. [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Valenti, E. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Munchen (Germany); Calamida, A. [National Optical Astronomy Observatory, 950 N Cherry Avenue, Tucson, AZ 85719 (United States); Da Silva, R.; Fabrizio, M.; Giuffrida, G. [ASDC, via del Politecnico snc, I-00133 Roma (Italy); Degl’Innocenti, S. [INFN, Sezione di Pisa, Largo Pontecorvo 3, I-56127, Pisa (Italy); Di Cecco, A. [INAF-Osservatorio Astronomico di Teramo, Via Mentore Maggini snc, Loc. Collurania, I-64100 Teramo (Italy); Freedman, W. L. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); and others

    2016-12-01

    New accurate and homogeneous optical UBVRI photometry has been obtained for variable stars in the Galactic globular cluster ω Cen (NGC 5139). We secured 8202 CCD images covering a time interval of 24 years and a sky area of 84 × 48 arcmin. The current data were complemented with data available in the literature and provided new, homogeneous pulsation parameters (mean magnitudes, luminosity amplitudes, periods) for 187 candidate ω Cen RR Lyrae (RRLs). Among them we have 101 RRc (first overtone) and 85 RRab (fundamental) variables, and a single candidate RRd (double-mode) variable. Candidate Blazhko RRLs show periods and colors that are intermediate between the RRc and RRab variables, suggesting that they are transitional objects. A comparison of the period distribution and the Bailey diagram indicates that RRLs in ω Cen show a long-period tail not present in typical Oosterhoff II (OoII) globulars. The RRLs in dwarf spheroidals and in ultra-faint dwarfs have properties between Oosterhoff intermediate and OoII clusters. Metallicity plays a key role in shaping the above evidence. These findings do not support the hypothesis that ω Cen is the core remnant of a spoiled dwarf galaxy. Using optical period–Wesenheit relations that are reddening-free and minimally dependent on metallicity we find a mean distance to ω Cen of 13.71 ± 0.08 ± 0.01 mag (semi-empirical and theoretical calibrations). Finally, we invert the I -band period–luminosity–metallicity relation to estimate individual RRLs’ metal abundances. The metallicity distribution agrees quite well with spectroscopic and photometric metallicity estimates available in the literature.

  14. Toward a Better Understanding of the Distance Scale from RR Lyrae Variable Stars: A Case Study for the Inner Halo Globular Cluster NGC 6723

    Science.gov (United States)

    Lee, Jae-Woo; López-Morales, Mercedes; Hong, Kyeongsoo; Kang, Young-Woon; Pohl, Brian L.; Walker, Alistair

    2014-01-01

    We present BV photometry for 54 variables in the metal-rich inner halo globular cluster NGC 6723. With the discovery of new RR Lyrae variables (RRLs), we obtain langP abrang = 0.541 ± 0.066 and langP crang = 0.292 ± 0.030 day, n(c)/n(ab+c) = 0.167, and langV(RR)rangint = 15.459 ± 0.055. We carry out the Fourier decomposition analysis and obtain [Fe/H]ZW = -1.23 ± 0.11 and E(B - V) = 0.063 ± 0.015 for NGC 6723. By calibrating the zero point from the recent absolute trigonometric parallax measurements for RR Lyr, we derive the revised MV (RR)-[Fe/H] relation, providing MV (RR) = 0.52 at [Fe/H] = -1.50 and (m - M)0 = 18.54 for the Large Magellanic Cloud, in excellent agreement with others. We obtain (m - M)0 = 14.65 ± 0.05, equivalent to a distance from the Sun of 8.47 ± 0.17 kpc, for NGC 6723 from various distance measurement methods using RRLs. We find that RRLs in NGC 6723 do not have magnitude dependency on the radial distance because there is not a severe degree of apparent crowdedness. Finally, we show that a relation exists between the degree of photometric contamination and the apparent crowdedness of the central region of globular cluster systems, |\\bar{\\mu } - \\mu _r| \\propto log \\rho _c d^2. The use of this relation can play a significant role in mitigating the discrepancy in establishing a cosmic distance scale using RRLs in resolved stellar populations in near-field cosmology. Partially based on observations made with telescopes operated by the SMARTS consortium.

  15. Metallic Line Doubling and van hoof Effect in the Spectra of the Variable Star RR Lyrae

    Science.gov (United States)

    Sefyani Lakrizi, Fouad; Benhida, Abdelmjid; Gillet, Denis; Mathias, phillipe; de France, Thibault; Benkhaldoun, Zouhair; Lazrek, Mohamed; Daassou, Ahmed

    2015-08-01

    The Oukaïmeden observatory is situated at an altitude of 2700m in the High Atlas mountain range, 78km south of Marrakech 7°52’52’’ west and 31°12’32’’ north. The quality of the sky is considered exceptional, not only for imaging but also for photometry. Indeed, the average measured seeing is of the order of 1 arc second which ensures high quality spectrum recording with a good signal-to-noise ratio. In this communication, we will present our observations of the phenomenon of metallic absorption lines, doubling in the spectra of the variable star RR Lyrae on Fe II (l4923.921 Å), as well as of sodium D lines. In emission, we observed the lines of hydrogen Hα, Hβ and Hγ with a very strong intensity (50 % above the continuum). We also observed the Van Hoof effect which consists of a difference between the radial velocity of the line of the Fe II (λ4923.921 Å) and that of the line Hβ. These observations were carried out with a small spectrograph of approximately 12000 resolution, installed on a 14 inch telescope, during the night of October 12th 2013. This date corresponded to the maximal phase of the Blazhko cycle. The doubling of the lines was interpreted by Schwarzschild on the basis of an atmosphere in two layers. Based on this interpretation we were able to measure the radial velocity of the shock wave deducted from the difference between both red and blue spectral components on the lines Hα of hydrogen, D of the sodium and the Fe II during the doubling of observed lines. The shock wave reached the maximal speed of 160 kms-1 so confirming the hypersonic regime to which atmosphere is submitted during this maximum phase of the Blazhko cycle. We will also present a comparison of our results with those obtained with high resolution spectrographs and thus confirm the validity of our results.

  16. Variaciones seculares de período en las RR Lyrae de ω~Centauri

    Science.gov (United States)

    Marraco, H. G.; Milesi, G. E.

    Utilizando 689 observaciones de 35 estrellas RR Lyrae del cúmulo globular ω Centauri hemos obtenido nuevas determinaciones de sus períodos y sus correspondientes variaciones seculares. Las observaciones fueron obtenidas de la literatura con la excepción de un grupo 66 determinaciones que se presentan por vez primera aquí. Utilizando el parámetro testigo σ descripto en Marraco & Muzzio (Publ. Astron. Soc. Pacific 92, 700, 1980), hemos realizado un ajuste bidimensional en P y β (donde β es la variación secular del período). Con este fin la totalidad de las 689 observaciones fueron llevadas a un sistema fotométrico común. Para esto se realizó un cuidadoso análisis de los numerosos errores en la identificación de las estrellas de las series de comparación. Los resultados de los ajustes bidimensionales fueron analizados utilizando técnicas de procesamiento de imágenes. Con este fin el parámetro de ajuste σ fue representado como función de P y β. En las imágenes resultantes se buscaron los mínimos y al menor de ellos se lo aceptó como período instantáneo verdadero y su variación secular β. La determinación precisa de cada parámetro se realizó mediante ajuste de gaussianas y se determinaron sus errores. A modo de ejemplo la variable #8 fue analizada en una matriz de 501 × 501 elementos representando el parámetro σ para valores comprendidos entre 0,521034 valores el parámetro testigo resulta σ= 0,127 . Si no se tiene en cuenta la variación secular del período y se busca aquél de mejor ajuste para β = 0, se obtiene P = 0,5212960 días, pero entonces el parámetro de ajuste resulta tan alto como σ = 0,23 .

  17. Constraints on the Distance Moduli, Helium and Metal Abundances, and Ages of Globular Clusters from their RR Lyrae and Non-variable Horizontal-branch Stars. I. M3, M15, and M92

    Science.gov (United States)

    VandenBerg, Don A.; Denissenkov, P. A.; Catelan, Márcio

    2016-08-01

    Up-to-date isochrones, zero-age horizontal-branch (ZAHB) loci, and evolutionary tracks for core He-burning stars are applied to the color-magnitude diagrams of M3, M15, and M92, focusing in particular on their RR Lyrae populations. Periods for the ab- and c-type variables are calculated using the latest theoretical calibrations of {log} {P}{ab} and {log} {P}c as a function of luminosity, mass, effective temperature ({T}{{eff}}), and metallicity. Our models are generally able to reproduce the measured periods to well within the uncertainties implied by the stellar properties on which pulsation periods depend, as well as the mean periods and cluster-to-cluster differences in and , on the assumption of well-supported values of E(B-V), {(m-M)}V, and [Fe/H]. While many of RR Lyrae in M3 lie close to the same ZAHB that fits the faintest horizontal-branch (HB) stars at bluer or redder colors, the M92 variables are all significantly evolved stars from ZAHB locations on the blue side of the instability strip. M15 appears to contain a similar population of HB stars as M92, along with additional helium-enhanced populations not present in the latter which comprise most of its RR Lyrae stars. The large number of variables in M15 and the similarity of the observed values of and in M15 and M92 can be explained by HB models that allow for variations in Y. Similar ages (˜12.5 Gyr) are found for all three clusters, making them significantly younger than the field halo subgiant HD 140283. Our analysis suggests a preference for stellar models that take diffusive processes into account.

  18. A Data-driven Study of RR Lyrae Near-IR Light Curves: Principal Component Analysis, Robust Fits, and Metallicity Estimates

    Science.gov (United States)

    Hajdu, Gergely; Dékány, István; Catelan, Márcio; Grebel, Eva K.; Jurcsik, Johanna

    2018-04-01

    RR Lyrae variables are widely used tracers of Galactic halo structure and kinematics, but they can also serve to constrain the distribution of the old stellar population in the Galactic bulge. With the aim of improving their near-infrared photometric characterization, we investigate their near-infrared light curves, as well as the empirical relationships between their light curve and metallicities using machine learning methods. We introduce a new, robust method for the estimation of the light-curve shapes, hence the average magnitudes of RR Lyrae variables in the K S band, by utilizing the first few principal components (PCs) as basis vectors, obtained from the PC analysis of a training set of light curves. Furthermore, we use the amplitudes of these PCs to predict the light-curve shape of each star in the J-band, allowing us to precisely determine their average magnitudes (hence colors), even in cases where only one J measurement is available. Finally, we demonstrate that the K S-band light-curve parameters of RR Lyrae variables, together with the period, allow the estimation of the metallicity of individual stars with an accuracy of ∼0.2–0.25 dex, providing valuable chemical information about old stellar populations bearing RR Lyrae variables. The methods presented here can be straightforwardly adopted for other classes of variable stars, bands, or for the estimation of other physical quantities.

  19. VizieR Online Data Catalog: CTIO/DECam photometry of RR Lyrae stars in M5 (Vivas+, 2017)

    Science.gov (United States)

    Vivas, A. K.; Saha, A.; Olsen, K.; Blum, R.; Olszewski, E. W.; Claver, J.; Valdes, F.; Axelrod, T.; Kaleida, C.; Kunder, A.; Narayan, G.; Matheson, T.; Walker, A.

    2017-11-01

    Observations were obtained during 2013 (2013 Jun 7-9, and 2013 Jun 21) and 2014 (2014 Mar 7-9) with the Dark Energy Camera (DECam) imager on the 4m Blanco Telescope at Cerro Tololo Inter-American Observatory (CTIO), Chile. Repeated DECam images of a field centered on M5 (R.A.=15:18:33.2, decl.=+02:04:51.7, J2000.0) were obtained using the u,g,r,i, and z filters. The large field of view (FOV) of DECam (2.2°) easily covers the whole globular cluster with only the central CCDs of the camera. A total of 66 RR Lyrae stars and 1 SX Phe were recognized in the field of M5. The individual measurements for the periodic variable stars are provided in Table2. In Table3, we present the list of periodic variable stars. (3 data files).

  20. EPIC 201585823, a rare triple-mode RR Lyrae star discovered in K2 mission data

    DEFF Research Database (Denmark)

    Kurtz, Donald W.; Bowman, Dominic M.; Ebo, Simon J.

    2016-01-01

    We have discovered a new, rare triple-mode RR Lyr star, EPIC 201585823, in the Kepler K2 mission Campaign 1 data. This star pulsates primarily in the fundamental and first-overtone radial modes, and, in addition, a third non-radial mode. The ratio of the period of the non-radial mode to that of t......We have discovered a new, rare triple-mode RR Lyr star, EPIC 201585823, in the Kepler K2 mission Campaign 1 data. This star pulsates primarily in the fundamental and first-overtone radial modes, and, in addition, a third non-radial mode. The ratio of the period of the non-radial mode...... to that of the first-overtone radial mode, 0.616 285, is remarkably similar to that seen in 11 other triple-mode RR Lyr stars, and in 260 RRc stars observed in the Galactic bulge. This systematic character promises new constraints on RR Lyr star models. We detected subharmonics of the non-radial mode frequency, which...

  1. The Araucaria Project: The Distance to the Fornax Dwarf Galaxy from Near-infrared Photometry of RR Lyrae Stars

    Science.gov (United States)

    Karczmarek, Paulina; Pietrzyński, Grzegorz; Górski, Marek; Gieren, Wolfgang; Bersier, David

    2017-12-01

    We have obtained single-phase near-infrared (NIR) magnitudes in the J and K bands for 77 RR Lyrae (RRL) stars in the Fornax Dwarf Spheroidal Galaxy. We have used different theoretical and empirical NIR period-luminosity-metallicity calibrations for RRL stars to derive their absolute magnitudes, and found a true, reddening-corrected distance modulus of 20.818+/- 0.015{{(statistical)}}+/- 0.116{{(systematic)}} mag. This value is in excellent agreement with the results obtained within the Araucaria Project from the NIR photometry of red clump stars (20.858 ± 0.013 mag), the tip of the red giant branch (20.84+/- 0.04+/- 0.14 mag), as well as with other independent distance determinations to this galaxy. The effect of metallicity and reddening is substantially reduced in the NIR domain, making this method a robust tool for accurate distance determination at the 5% level. This precision is expected to reach the level of 3% once the zero points of distance calibrations are refined thanks to the Gaia mission. NIR period-luminosity-metallicity relations of RRL stars are particularly useful for distance determinations to galaxies and globular clusters up to 300 kpc, that lack young standard candles, like Cepheids. Based on data collected with the VLT/HAWK-I instrument at ESO Paranal Observatory, Chile, as a part of programme 082.D-0123(B).

  2. VizieR Online Data Catalog: RR Lyrae stars from the PS1 3π survey (Sesar+, 2017)

    Science.gov (United States)

    Sesar, B.; Hernitschek, N.; Mitrovic, S.; Ivezic, Z.; Rix, H.-W.; Cohen, J. G.; Bernard, E. J.; Grebel, E. K.; Martin, N. F.; Schlafly, E. F.; Burgett, W. S.; Draper, P. W.; Flewelling, H.; Kaiser, N.; Kudritzki, R. P.; Magnier, E. A.; Metcalfe, N.; Tonry, J. L.; Waters, C.

    2018-04-01

    Building on the work by Hernitschek+ (2016, J/ApJ/817/73), in this paper, we use the final PS1 data release (PV3) to significantly increase the completeness and purity of the PS1 sample of RR Lyrae stars. Pan-STARRS1 (PS1; Kaiser+ 2010, see II/349) is a wide-field optical/near-IR survey telescope system located at the Haleakala Observatory on the island of Maui in Hawai'i. The largest survey undertaken by the telescope, the PS1 3π survey (Chambers K.C. 2011, BAAS, 43, 113.01), has observed the entire sky north of decl. -30° in five filter bands, reaching 5σ single-epoch depths of about 22.0, 22.0, 21.9, 21.0, and 19.8mag in gP1, rP1, iP1, zP1, and yP1 bands, respectively. The uncertainty in photometric calibration of the survey is <~0.01mag, and the astrometric precision of single-epoch detections is 10mas. (4 data files).

  3. The Distance to M54 using Infrared Photometry of RR Lyrae Variable Stars and the Implications of its Relation to the Sagittarius Dwarf Galaxy

    Science.gov (United States)

    Gupta, Arvind F.; Beaton, Rachael L.; Majewski, Steven R.; SMHASH Team

    2018-01-01

    CDM cosmological models predict that dark matter halo density profiles will have central cusps. Yet for many dwarf spheroidal galaxies (dSphs), this expectation is in contrast with observations of cored, rather than cusped, halos. This 'cusp-core problem' is apparent in the Sagittarius Dwarf Galaxy (Sgr), one of the largest satellites of the Milky Way. The globular cluster M54, one of several clusters associated with Sgr, coincides in on-sky position with the center of the main body of Sgr. While several studies find that M54 lies within the center of Sgr, other findings show that M54 is offset from the center by several kiloparsecs along our line of sight. The latter requires Sgr to have a cored dark matter distribution. In the presence of a cuspy halo, the orbit of M54 would have decayed via dynamical friction and the cluster would have fallen to the center of Sgr. A clear determination of the relation of the two bodies may help us better understand the distribution of dark matter in Sgr and other dSphs. Here we present a measurement of the distance modulus to M54 using a set of RR Lyrae variable stars in near-infrared Magellan data mid-infrared Spitzer data. The magnitudes of individual stars are measured using multi-epoch PSF photometry and light curve fitting. From precise RR Lyrae period-luminosity relations at these wavelengths, we then find the mean M54 distance modulus to be 17.126 ± 0.023 (ran) ± 0.080 (sys). Our result is consistent with a distance measurement to Sgr derived via nearly identical methods and thus also consistent with the expectation of a central cusp in the dark matter density profile of Sgr.

  4. Pulsating star products from the Palomar Transient Factory: Ultra-long period Cepheids in M31 and RR Lyrae in Kepler field

    Directory of Open Access Journals (Sweden)

    Ngeow Chow-Choong

    2017-01-01

    Full Text Available The Palomar Transient Factory (PTF and its successor, the intermediate PTF (iPTF, are wide-field synoptic sky surveys aimed to detect transients. Even though the main science goal for PTF/iPTF is to detect various types of transients, the synoptic nature of the surveys can also be used for the study of variable stars. In this proceedings contribution, I will first give a brief introduction to PTF/iPTF, followed by the two pulsating stars studies using the PTF/iPTF data: the Ultra-Long Period Cepheids (ULPC in M31 and the RR Lyrae in the Kepler field. For the formal study, we searched the M31’s ULPC using PTF imaging data, and follow up the candidates with other telescopes. Our finding revealed that there are only two ULPC in M31. I will give a brief implication of our finding in distance scale studies. For the latter study, I will present our work on the derivation of metallicity-light curve relation in native PTF/iPTF R-band using the RRab stars in the Kepler field.

  5. A Near-infrared RR Lyrae Census along the Southern Galactic Plane: The Milky Way’s Stellar Fossil Brought to Light

    Science.gov (United States)

    Dékány, István; Hajdu, Gergely; Grebel, Eva K.; Catelan, Márcio; Elorrieta, Felipe; Eyheramendy, Susana; Majaess, Daniel; Jordán, Andrés

    2018-04-01

    RR Lyrae stars (RRLs) are tracers of the Milky Way’s fossil record, holding valuable information on its formation and early evolution. Owing to the high interstellar extinction endemic to the Galactic plane, distant RRLs lying at low Galactic latitudes have been elusive. We attained a census of 1892 high-confidence RRLs by exploiting the near-infrared photometric database of the VVV survey’s disk footprint spanning ∼70° of Galactic longitude, using a machine-learned classifier. Novel data-driven methods were employed to accurately characterize their spatial distribution using sparsely sampled multi-band photometry. The RRL metallicity distribution function (MDF) was derived from their K s -band light-curve parameters using machine-learning methods. The MDF shows remarkable structural similarities to both the spectroscopic MDF of red clump giants and the MDF of bulge RRLs. We model the MDF with a multi-component density distribution and find that the number density of stars associated with the different model components systematically changes with both the Galactocentric radius and vertical distance from the Galactic plane, equivalent to weak metallicity gradients. Based on the consistency with results from the ARGOS survey, three MDF modes are attributed to the old disk populations, while the most metal-poor RRLs are probably halo interlopers. We propose that the dominant [Fe/H] component with a mean of ‑1 dex might correspond to the outskirts of an ancient Galactic spheroid or classical bulge component residing in the central Milky Way. The physical origins of the RRLs in this study need to be verified by kinematical information.

  6. An optimized method to identify RR Lyrae stars in the SDSS×Pan-STARRS1 overlapping area using a bayesian generative technique

    International Nuclear Information System (INIS)

    Abbas, Mohamad; Grebel, Eva K.; Martin, N. F.; Kaiser, N.; Burgett, W. S.; Huber, M. E.; Waters, C.

    2014-01-01

    We present a method for selecting RR Lyrae (RRL) stars (or other types of variable stars) in the absence of a large number of multi-epoch data and light curve analyses. Our method uses color and variability selection cuts that are defined by applying a Gaussian Mixture Bayesian Generative Method (GMM) on 636 pre-identified RRL stars instead of applying the commonly used rectangular cuts. Specifically, our method selects 8115 RRL candidates (heliocentric distances < 70 kpc) using GMM color cuts from the Sloan Digital Sky Survey (SDSS) and GMM variability cuts from the Panoramic Survey Telescope and Rapid Response System 1 3π survey (PS1). Comparing our method with the Stripe 82 catalog of RRL stars shows that the efficiency and completeness levels of our method are ∼77% and ∼52%, respectively. Most contaminants are either non-variable main-sequence stars or stars in eclipsing systems. The method described here efficiently recovers known stellar halo substructures. It is expected that the current completeness and efficiency levels will further improve with the additional PS1 epochs (∼3 epochs per filter) that will be observed before the conclusion of the survey. A comparison between our efficiency and completeness levels using the GMM method to the efficiency and completeness levels using rectangular cuts that are commonly used yielded a significant increase in the efficiency level from ∼13% to ∼77% and an insignificant change in the completeness levels. Hence, we favor using the GMM technique in future studies. Although we develop it over the SDSS×PS1 footprint, the technique presented here would work well on any multi-band, multi-epoch survey for which the number of epochs is limited.

  7. On a New Theoretical Framework for RR Lyrae Stars. II. Mid-infrared Period–Luminosity–Metallicity Relations

    Energy Technology Data Exchange (ETDEWEB)

    Neeley, Jillian R.; Marengo, Massimo; Trueba, Nicolas [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Bono, Giuseppe; Braga, Vittorio F.; Magurno, Davide [Department of Physics, Università di Roma Tor Vergara, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Dall’Ora, Massimo; Marconi, Marcella [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiarello 16, I-80131 Napoli (Italy); Tognelli, Emanuele; Moroni, Pier G. Prada [Dipartimento di Fisica, Università di Pisa, Lago Bruno Pontecorvo 3, I-56127, Pisa (Italy); Beaton, Rachael L.; Madore, Barry F.; Seibert, Mark [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Freedman, Wendy L. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Monson, Andrew J. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Scowcroft, Victoria [Department of Physics, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Stetson, Peter B., E-mail: jrneeley@iastate.edu [NRC-Herzberg, Dominion Astrophysical Observatory, 5071 West Saanich Road, Victoria BC V9E 2E7 (Canada)

    2017-06-01

    We present new theoretical period–luminosity–metallicity (PLZ) relations for RR Lyræ stars (RRLs) at Spitzer and WISE wavelengths. The PLZ relations were derived using nonlinear, time-dependent convective hydrodynamical models for a broad range of metal abundances ( Z = 0.0001–0.0198). In deriving the light curves, we tested two sets of atmospheric models and found no significant difference between the resulting mean magnitudes. We also compare our theoretical relations to empirical relations derived from RRLs in both the field and in the globular cluster M4. Our theoretical PLZ relations were combined with multi-wavelength observations to simultaneously fit the distance modulus, μ {sub 0}, and extinction, A {sub V}, of both the individual Galactic RRL and of the cluster M4. The results for the Galactic RRL are consistent with trigonometric parallax measurements from Gaia ’ s first data release. For M4, we find a distance modulus of μ {sub 0} = 11.257 ± 0.035 mag with A {sub V}= 1.45 ± 0.12 mag, which is consistent with measurements from other distance indicators. This analysis has shown that, when considering a sample covering a range of iron abundances, the metallicity spread introduces a dispersion in the PL relation on the order of 0.13 mag. However, if this metallicity component is accounted for in a PLZ relation, the dispersion is reduced to ∼0.02 mag at mid-infrared wavelengths.

  8. Anisotropic Lyra cosmology

    Indian Academy of Sciences (India)

    Anisotropic Bianchi Type-I cosmological models have been studied on the basis of Lyra's geometry. Two types of models, one with constant deceleration parameter and the other with variable deceleration parameter have been derived by considering a time-dependent displacement field.

  9. Dynamical investigation of modulated Kepler RR Lyrae stars

    Directory of Open Access Journals (Sweden)

    Plachy E.

    2015-01-01

    Full Text Available We performed a non-linear dynamical analysis on the Blazhko modulation for the first time. Our results suggest that the detection of chaotic nature behind the phenomenon is limited by the instrumental effects and the data processing problems of the Kepler pipeline concerning high-amplitude variable stars.

  10. Testing parallaxes with local Cepheids and RR Lyrae stars

    Czech Academy of Sciences Publication Activity Database

    Clementini, G.; Eyer, L.; Ripepi, V.; Marconi, M.; Muraveva, T.; Garofalo, A.; Sarro, L.M.; Palmer, M.; Luri, X.; Koubský, Pavel; Votruba, Viktor

    2017-01-01

    Roč. 605, September (2017), A79/1-A79/29 E-ISSN 1432-0746 R&D Projects: GA MŠk(CZ) LG15010 Grant - others:ESA(XE) ESA-PECS project no. 98058 Institutional support: RVO:67985815 Keywords : astrometry * parallaxes * stars Subject RIV: BN - Astronomy , Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 5.014, year: 2016

  11. Static traversable wormholes in Lyra manifold

    Science.gov (United States)

    Jahromi, A. Sayahian; Moradpour, H.

    At first, considering the Einstein framework, we introduce some new static traversable wormholes and study the effects of a dark energy-like source on them. Thereinafter, a brief review on Einstein field equations in Lyra manifold is presented, and we address some static traversable wormholes in the Lyra manifold which satisfy the energy conditions. It is also shown that solutions introduced in the Einstein framework may also meet the energy conditions in the Lyra manifold. Finally, we focus on vacuum Lyra manifold and find some traversable asymptotically flat wormholes. In summary, our study shows that it is theoretically possible to find a Lyra displacement vector field in a manner in which traversable wormholes satisfy the energy conditions in a Lyra manifold.

  12. RR photons

    CERN Document Server

    Camara, Pablo G; Marchesano, Fernando

    2011-01-01

    Type II string compactifications to 4d generically contain massless Ramond-Ramond U(1) gauge symmetries. However there is no massless matter charged under these U(1)'s, which makes a priori difficult to measure any physical consequences of their existence. There is however a window of opportunity if these RR U(1)'s mix with the hypercharge $U(1)_Y$ (hence with the photon). In this paper we study in detail different avenues by which $U(1)_{RR}$ bosons may mix with D-brane U(1)'s. We concentrate on Type IIA orientifolds and their M-theory lift, and provide geometric criteria for the existence of such mixing, which may occur either via standard kinetic mixing or via the mass terms induced by St\\"uckelberg couplings. The latter case is particularly interesting, and appears whenever D-branes wrap torsional $p$-cycles in the compactification manifold. We also show that in the presence of torsional cycles discrete gauge symmetries and Aharanov-Bohm strings and particles appear in the 4d effective action, and that ty...

  13. Higher dimensional homogeneous cosmology in Lyra geometry

    Indian Academy of Sciences (India)

    Assuming a homogeneous perfect fluid with ρ = ρ() and = (), we have obtained exact solutions for cosmological models in higher-dimension based on Lyra geometry. Depending on the form of metric chosen, the model is similar to FRW type. The explicit solutions of the scale factor are found via the assumption of an ...

  14. Higher dimensional homogeneous cosmology in Lyra geometry

    Indian Academy of Sciences (India)

    ρ´tµ and p p´tµ, we have obtained exact solutions for cosmological models in higher-dimension based on Lyra geometry. Depending on the form of metric chosen, the model is similar to FRW type. The explicit solutions of the scale factor are found via the assumption of an equation of state p mρ, where m is a constant. Some.

  15. Bianchi-IX string cosmological model in Lyra geometry

    Indian Academy of Sciences (India)

    The most important among them are scalar–tensor theories proposed by Lyra. [6] and Brans–Dicke [6]. Lyra [6] proposed a modification of Riemannian geometry by introducing a gauge function into the structureless manifold that bears a close resemblance to Weyl's geometry. In general relativity, Einstein succeeded in ...

  16. Bianchi-IX string cosmological model in Lyra geometry

    Indian Academy of Sciences (India)

    Abstract. A class of cosmological solutions of massive strings for the Bianchi-IX space-time are obtained within the framework of Lyra geometry. Various physical and kinematical properties of the models are discussed.

  17. The ultraviolet spectrum of beta Lyrae

    International Nuclear Information System (INIS)

    Hack, M.; Hutchings, J.B.; Kondo, Y.; McCluskey, G.E.; Plavec, M.; Polidan, R.S.

    1975-01-01

    Details are presented of low-resolution (0.2--0.4 A) scans of the spectrum of β Lyrae in the region 1000-3000 A, obtained from the Copernicus OAO. The continuous spectrum appears to correspond to type B5 or later, while the line spectrum is largely dominated by very strong emission of lines characteristic of earlier spectral types. Small velocity variations, similar to those of the shell lines in the visible spectrum, are seen. Consideration of the intensity variations and profiles of the lines suggests that the ultraviolet emission lines originate in a large rotating, expanding volume, probably centered on the secondary star. No features can be identified with the secondary star itself. A discussion of models for the system is given, and it is considered that present evidence suggests that the second object is a mass-accreting black hole

  18. LYRA, a webserver for lymphocyte receptor structural modeling.

    Science.gov (United States)

    Klausen, Michael Schantz; Anderson, Mads Valdemar; Jespersen, Martin Closter; Nielsen, Morten; Marcatili, Paolo

    2015-07-01

    The accurate structural modeling of B- and T-cell receptors is fundamental to gain a detailed insight in the mechanisms underlying immunity and in developing new drugs and therapies. The LYRA (LYmphocyte Receptor Automated modeling) web server (http://www.cbs.dtu.dk/services/LYRA/) implements a complete and automated method for building of B- and T-cell receptor structural models starting from their amino acid sequence alone. The webserver is freely available and easy to use for non-specialists. Upon submission, LYRA automatically generates alignments using ad hoc profiles, predicts the structural class of each hypervariable loop, selects the best templates in an automatic fashion, and provides within minutes a complete 3D model that can be downloaded or inspected online. Experienced users can manually select or exclude template structures according to case specific information. LYRA is based on the canonical structure method, that in the last 30 years has been successfully used to generate antibody models of high accuracy, and in our benchmarks this approach proves to achieve similarly good results on TCR modeling, with a benchmarked average RMSD accuracy of 1.29 and 1.48 Å for B- and T-cell receptors, respectively. To the best of our knowledge, LYRA is the first automated server for the prediction of TCR structure. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  19. Kepler photometry of the prototypical Blazhko star RR Lyr: an old friend seen in a new light

    DEFF Research Database (Denmark)

    Kolenberg, Katrien; Bryson, S.; Szabó, R.

    2011-01-01

    We present our analysis of the long-cadence Kepler data for the well-studied Blazhko star RR Lyr, gathered during the first two quarters of the satellite's observations and covering a total of 127 d. Besides being of great importance for our understanding of RR Lyrae stars in general, these RR Lyr......-cadence sampling (one measurement per 29.4 min), the unprecedented precision (light-curve variations in detail. The multiplet structures at the main frequency and its harmonics, typical for Blazhko stars, are clearly detected up...... that there is no exact repetition in the light-curve changes from one modulation cycle to the next for RR Lyr. This may be due to additional periodicities in the star, or to transient or quasi-periodic changes....

  20. Higher-dimensional string theory in Lyra geometry

    Indian Academy of Sciences (India)

    Riemannian geometry. Halford [11] has pointed out that the constant displacement fieldφi in Lyra's geometry play the role of cosmological constant Λ in the normal general relativistic treatment. Ac- cording to Halford the present theory predicts the same effects within observational limits, as far as the classical solar system ...

  1. Bianchi-IX string cosmological model in Lyra geometry

    Indian Academy of Sciences (India)

    field in Lyra's geometry will either include a creation field and be equal to Hoyle's cre- ation field cosmology or contain a special vacuum field which together with the gauge vector term may be considered as a cosmological term. Subsequent investigations were done by several authors in scalar–tensor theory and cos-.

  2. Spectrophotometry of RR Telescopii

    International Nuclear Information System (INIS)

    Walker, A.R.

    1977-01-01

    The strongest emission lines in the nova-like variable RR Telescopii were measured during late 1974 using a spectrum scanner. The wavelength range 3350 to 7700 A was scanned with a resolution of 50 A. The results are compared with published spectrophotometry covering the period 1961 to 72, with the conclusion that few changes have taken place in the last 6 yr. No evidence was found that suggested the existence of a cool star, nor was there any indication of night-to-night changes in the emission line intensities. The spectrophotometry of the past 15 yr is consistent with an expanding shell, the emission from this shell being caused by high-energy radiation from an underlying star. (author)

  3. LYRA, a webserver for lymphocyte receptor structural modeling

    DEFF Research Database (Denmark)

    Klausen, Michael Schantz; Anderson, Mads Valdemar; Jespersen, Martin Closter

    2015-01-01

    the structural class of each hypervariable loop, selects the best templates in an automatic fashion, and provides within minutes a complete 3D model that can be downloaded or inspected online. Experienced users can manually select or exclude template structures according to case specific information. LYRA...... is based on the canonical structure method, that in the last 30 years has been successfully used to generate antibody models of high accuracy, and in our benchmarks this approach proves to achieve similarly good results on TCR modeling, with a benchmarked average RMSD accuracy of 1.29 and 1.48 Å for B...

  4. On the problem of the chemical composition of β Lyrae

    International Nuclear Information System (INIS)

    Bahyl, V.

    1982-01-01

    Two determinations of helium abundance in the primary β Lyrae's component existed before 1975. According to Boyarchuk (1959) helium is 631 times overabundant relative to hydrogen and according to Hack and Job (1965) the ratio He/H varies from 1 to 2.25 depending on the effective temperature. The author has examined this problem with the aim of deciding between these extreme results. He started from models of the atmosphere and calculated the theoretical profiles. He has found the best fit for the model Boehm-Vitense (1967), Tsub(eff) = 12,900K, log g = 2 and He/H = 2.72. (Auth.)

  5. UV-by photometry in M39 and delta Lyrae

    Energy Technology Data Exchange (ETDEWEB)

    Anthony-Twarog, B.J.

    1984-05-01

    Photoelectric UV-by observations have been obtained for stars in the mid-B to early-A spectral range in the fields of M39 and delta Lyrae. The color and luminosity calibrations of Crawford for B, A, and F stars have been employed, as well as the new calibration for A0 stars of Hilditch et al. (1983). The resulting distance modulus for M39 is 7.23, with a mean E(b-y) color excess of 0.025. A distance modulus of 7.29 and a mean reddening of 0.032 has been derived for ten stars in the field of delta Lyrae, but the existence of a cluster is not strongly indicated in the present study. Comparison of photometric and rotational velocity data for the M39 stars confirms a correlation between deltac/sub 0/ and rotational velocity for A and A0 stars, and suggests that an evolutionary correction of only -3deltac/sub 0/ be employed for stars in both spectral classes.

  6. First detection of multi-shocks in RR Lyrae stars from Antarctica : A possible explanation of the Blazhko effect

    International Nuclear Information System (INIS)

    Chadid, M.; Vernin, J.; Zalian, C.; Pouzenc, C.; Abe, L.; Agabi, A.; Aristidi, E.; Mékarnia, D.; Preston, G.; Liu, L.Y.; Trinquet, H.

    2014-01-01

    We present the first detection of multi-shocks propagating through the atmosphere of the Blazhko star S Arae using uninterrupted, accurate optical photometric data collected during one polar night, 150 days from Antarctica at Dome C, with the Photometer AntarctIca eXtinction (PAIX). We acquired 89,736 CCD frames during 323 pulsation cycles and 3 Blazhko cycles. We detected two new light curve properties in the PAIX light curve, jump and rump, which we associated with two new post-maximum shock waves Sh PM1 and Sh PM2 . jump, lump, rump, bump, and hump are induced by five shock waves, with different amplitudes and origins, Sh PM1 , Sh PM , Sh PM2 , Sh PM3 , and the main shock Sh H+He . Correlations between the length of rise time and light amplitude and Sh PM3 are monotonous during three Blazhko cycles, but the pulsation curve is double peaked. We discuss the physical mechanisms driving the modulation of these quantities. Finally, we hypothesize that the origin of the Blazhko effect is a dynamical interaction between a multi-shock structure and an outflowing wind in a coronal structure.

  7. First detection of multi-shocks in RR Lyrae stars from Antarctica : A possible explanation of the Blazhko effect

    Energy Technology Data Exchange (ETDEWEB)

    Chadid, M.; Vernin, J.; Zalian, C.; Pouzenc, C.; Abe, L.; Agabi, A.; Aristidi, E.; Mékarnia, D. [Université Nice Sophia-Antipolis, Observatoire de la Côte d' Azur, UMR 7293, Parc Valrose, F-06108 Nice Cedex 02 (France); Preston, G. [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Liu, L.Y. [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing (China); Trinquet, H., E-mail: chadid@unice.fr [DGA Matrise de l' Information, BP 7, F-35998 Rennes Armees (France)

    2014-11-01

    We present the first detection of multi-shocks propagating through the atmosphere of the Blazhko star S Arae using uninterrupted, accurate optical photometric data collected during one polar night, 150 days from Antarctica at Dome C, with the Photometer AntarctIca eXtinction (PAIX). We acquired 89,736 CCD frames during 323 pulsation cycles and 3 Blazhko cycles. We detected two new light curve properties in the PAIX light curve, jump and rump, which we associated with two new post-maximum shock waves Sh{sub PM1} and Sh{sub PM2}. jump, lump, rump, bump, and hump are induced by five shock waves, with different amplitudes and origins, Sh{sub PM1}, Sh{sub PM}, Sh{sub PM2}, Sh{sub PM3}, and the main shock Sh{sub H+He}. Correlations between the length of rise time and light amplitude and Sh{sub PM3} are monotonous during three Blazhko cycles, but the pulsation curve is double peaked. We discuss the physical mechanisms driving the modulation of these quantities. Finally, we hypothesize that the origin of the Blazhko effect is a dynamical interaction between a multi-shock structure and an outflowing wind in a coronal structure.

  8. A cautionary tale of interpreting O-C diagrams: period instability in a classical RR Lyr Star Z CVn mimicking as a distant companion

    Science.gov (United States)

    Skarka, M.; Liška, J.; Dřevěný, R.; Guggenberger, E.; Sódor, Á.; Barnes, T. G.; Kolenberg, K.

    2018-02-01

    We present a comprehensive study of Z CVn, an RR Lyrae star that shows long-term cyclic variations of its pulsation period. A possible explanation suggested from the shape of the O-C diagram is the light travel-time effect, which we thoroughly examine. We used original photometric and spectroscopic measurements and investigated the period evolution using available maximum times spanning more than one century. If the binary hypothesis is valid, Z CVn orbits around a black hole with minimal mass of 56.5 M_{⊙} on a very wide (Porbit = 78.3 yr) and eccentric orbit (e = 0.63). We discuss the probability of the formation of a black hole-RR Lyrae pair, and, although we found it possible, there is no observational evidence of the black hole in the direction to Z CVn. However, the main objection against the binary hypothesis is the comparison of the systemic radial velocity curve model and spectroscopic observations that clearly show that Z CVn cannot be bound in such a binary. Therefore, the variations of pulsation period are likely intrinsic to the star. This finding represents a discovery/confirmation of a new type of cyclic period changes in RR Lyrae stars. By the analysis of our photometric data, we found that the Blazhko modulation with period of 22.931 d is strongly dominant in amplitude. The strength of the phase modulation varies and is currently almost undetectable. We also estimated photometric physical parameters of Z CVn and investigated their variations during the Blazhko cycle using the inverse Baade-Wesselink method.

  9. Bianchi Type-I cosmological mesonic stiff fluid models in Lyra's ...

    Indian Academy of Sciences (India)

    Bianchi Type-I cosmological models in Lyra's geometry are obtained when the source of gravitational field is a perfect fluid coupled with massless mesonic scalar field. Some physical and kinematical properties of the models are also discussed.

  10. Navy Prototype Optical Interferometer Imaging of Line Emission Regions of Beta Lyrae Using Differential Phase Referencing

    National Research Council Canada - National Science Library

    Schmitt, H. R; Pauls, T. A; Tycner, C; Armstrong, J. T; Zavala, R. T; Benson, J. A; Gilbreath, G. C; Hindsley, R. B; Hutter, D. J; Johnston, K. J; Jorgensen, A. M; Mozurkewich, D

    2009-01-01

    ... have interferometric phases near zero. We used this property to correct for the effects of the instrument and atmosphere on the phases of Beta Lyrae and to obtain differential phases in the channel...

  11. High temperature plasma in β Lyrae observed from Copernicus

    International Nuclear Information System (INIS)

    Konda, Y.; McCluskey, G.E. Jr.; Plavec, M.; Polidan, R.S.

    1975-01-01

    High-resolution ultraviolet spectrophotometry of the complex close binary system βLyrae was performed with the Princeton Telescope Spectrometer on Copernicus. Observations were made at phases 0.0, 0.25, 0.5, and 0.75 with the resolution of 0.2A (far-ultraviolet) and 0.4A (mid-ultraviolet). The far-ultraviolet spectrum is completely dominated by emission lines indicating existence of high temperature plasma in the binary. The spectrum of this object is unlike any other object observed from Copernicus. It is believed that this high temperature plasma results from dynamic mass transfer taking place in this binary. The current results are compared with the OAO-2Wisconsin Experiment Package observations and other observational results. The possibility that the secondary component is a collapsed object is also discussed; the Copernicus observations are consistent with the hypothesis that the spectroscopically invisible secondary component is a black hole. (Auth.)

  12. LYRA, solar uv radiometer on the technology demonstration platform PROBA-2

    Science.gov (United States)

    Stockman, Y.; Hochedez, J.-F.; Schmutz, W.; BenMoussa, A.; Defise, J.-M.; Denis, F.; D'Olieslaeger, M.; Dominique, M.; Haenen, K.; Halain, J.-P.; Koller, S.; Koizumi, S.; Mortet, V.; Rochus, P.; Schühle, U.; Soltani, A.; Theissen, A.

    2017-11-01

    LYRA is a solar radiometer part of the PROBA 2 micro satellite payload. LYRA will monitor the solar irradiance in four soft X-Ray - VUV passbands. They have been chosen for their relevance to Solar Physics, Aeronomy and SpaceWeather: 1/ Lyman Alpha channel, 2/ Herzberg continuum range, 3/ Aluminium filter channel (including He II at 30.4 nm) and 4/ Zirconium filter channel. The radiometric calibration is traceable to synchrotron source standards. The stability will be monitored by on-board calibration sources (LEDs), which allow us to distinguish between potential degradations of the detectors and filters. Additionally, a redundancy strategy maximizes the accuracy and the stability of the measurements. LYRA will benefit from wide bandgap detectors based on diamond: it will be the first space assessment of revolutionary UV detectors. Diamond sensors make the instruments radiation-hard and solar-blind (insensitive to visible light) and therefore, make dispensable visible light blocking filters. To correlate the data of this new detector technology, well known technology, such as Si detectors are also embarked. The SWAP EUV imaging telescope will operate next to LYRA on PROBA-2. Together, they will provide a high performance solar monitor for operational space weather nowcasting and research. LYRA demonstrates technologies important for future missions such as the ESA Solar Orbiter.

  13. Variations in EUV Irradiance: Comparison between LYRA, ESP, and SWAP Integrated Flux

    Directory of Open Access Journals (Sweden)

    Mehmet Sarp Yalim

    2014-01-01

    Full Text Available The Sun Watcher Using Active Pixel System Detector and Image Processing (SWAP telescope and Large Yield Radiometer (LYRA are the two Sun observation instruments on-board PROBA2. SWAP extreme ultraviolet images, if presented in terms of the integrated flux over solar disk, in general, correlate well with LYRA channel 2–4 (zirconium filter and channels QD and 18 of EVE/ESP on-board SDO between 2010 and 2013. Hence, SWAP can be considered as an additional radiometric channel. We compare in detail LYRA channel 2–4 and SWAP integrated flux in July 2010 and in particular during the solar eclipse that occurred on July 11, 2010. During this eclipse, the discrepancy between the two data channels can be explained to be related to the occultation of active region 11087 by the Moon. In the second half of July 2010, LYRA channel 2–4 and SWAP integrated flux deviate from each other, but these differences can also be explained in terms of features appearing on the solar disk such as coronal holes and active regions. By additionally comparing with timeline of EVE/ESP, we can preliminarily interpret these differences in terms of the difference between the broad bandpass of LYRA channel 2–4 and the, relatively speaking, narrower bandpass of SWAP.

  14. Dietary preference and feeding selectivity of common dragonet Callionymus lyra in U.K.

    Science.gov (United States)

    Griffin, R; Pearce, B; Handy, R D

    2012-08-01

    The gut contents of 90 individuals of common dragonet Callionymus lyra were analysed, of which 76 contained prey, along with 100 corresponding benthic grab samples in order to assess the diet of C. lyra in relation to the availability of its prey in the environment. Forty-five prey taxa were identified in the diet from 350 potential prey taxa identified in the environment. Calculation of the index of relative importance (I(RI)) found the main food components were crustaceans (%I(RI) = 86·3), mostly the porcelain crab Pisidia longicornis (%I(RI) = 43) and other decapods (%I(RI) = 18). Polychaetes played only a supplementary role in the overall diet (%I(RI) = 12·5). This study demonstrated that C. lyra is predominantly an opportunistic feeder that can modify its feeding behaviour to exploit alternative, more abundant prey. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  15. Multicenter evaluation of the Quidel Lyra Direct C. difficile nucleic acid amplification assay.

    Science.gov (United States)

    Beck, Eric T; Buchan, Blake W; Riebe, Katherine M; Alkins, Brenda R; Pancholi, Preeti; Granato, Paul A; Ledeboer, Nathan A

    2014-06-01

    Clostridium difficile is a Gram-positive bacterium commonly found in health care and long-term-care facilities and is the most common cause of antibiotic-associated diarrhea. Rapid detection of this bacterium can assist physicians in implementing contact precautions and appropriate antibiotic therapy in a timely manner. The purpose of this study was to compare the clinical performance of the Quidel Lyra Direct C. difficile assay (Lyra assay) (Quidel, San Diego, CA) to that of a direct cell culture cytotoxicity neutralization assay (CCNA) and enhanced toxigenic culture. This study was performed at three geographically diverse laboratories within the United States using residual stool specimens submitted for routine C. difficile testing. Residual samples were tested using the Lyra assay on three real-time PCR platforms, and results were compared to those for direct CCNA and enhanced toxigenic culture. The test results for all platforms were consistent across all three test sites. The sensitivity and specificity of the Lyra assay on the SmartCycler II, ABI 7500 Fast DX, and ABI QuantStudio DX instruments compared to CCNA were 90.0% and 93.3%, 95.0% and 94.2%, and 93.8% and 95.0%, respectively. Compared to enhanced toxigenic culture, the sensitivity and specificity of the Lyra assay on the SmartCycler II, ABI 7500, and QuantStudio instruments were 82.1% and 96.9%, 89.3% and 98.8%, and 85.7% and 99.0%, respectively. Overall, the Lyra assay is easy to use and versatile and compares well to C. difficile culture methods. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  16. New polymorphic microsatellite markers in the greater false vampire bat Megaderma lyra (Chiroptera: Megadermatidae)

    Czech Academy of Sciences Publication Activity Database

    Tereba, A.; Čížková, Dagmar; Sundari, A. A.; Rajan, K. E.; Bogdanowicz, W.

    2011-01-01

    Roč. 3, č. 4 (2011), s. 749-751 ISSN 1877-7252 Institutional research plan: CEZ:AV0Z60930519 Keywords : Chiroptera * Megaderma lyra * Microsatellites * Polymorphism Subject RIV: EG - Zoology Impact factor: 0.485, year: 2011

  17. Bianchi Type-I cosmological mesonic stiff fluid models in Lyra's ...

    Indian Academy of Sciences (India)

    Introduction. Based on the cosmological principle, Einstein introduced the cosmological constant into his field equations in order to obtain a static model of the Universe since ... momentum tensor Tij is not conserved in Lyra's geometry. ... are respectively the energy–momentum tensors corresponding to perfect fluid and.

  18. NESDIS Blended Rain Rate (RR) Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The blended Rain Rate (RR) product is derived from multiple sensors/satellites. The blended products were merged from polar-orbiting and geostationary satellite...

  19. CCD photometry in the Vilnius photometric system. I. region in Lyra

    International Nuclear Information System (INIS)

    Boyle, R.P.; Smriglio, F.; Straizys, V.

    1990-01-01

    Three-dimensional photometric classification can be made for stars measured in the Vilnius seven-color intermediate-band system, even if they are reddened by dust. Such classification is important for questions relating to the structure and evolution of our Galaxy. Presented here for general use is CCD photometry of 231 field stars in Lyra observed with the 0.9 meter telescope of Kitt Peak National Observatory. The measurements are of higher accuracy than those of a photographic study in the same direction in Lyra for which they can also be used for a deeper calibration of the photographic photometry. The data sets cover two small fields each about 31 arcmin 2 and are complete to 90% for all stars up to the faint limit of V = 17.5

  20. A preliminary examination of genetic diversity in the Indian false vampire bat Megaderma lyra

    Directory of Open Access Journals (Sweden)

    Emmanuvel Rajan, K.

    2006-12-01

    Full Text Available Habitat loss and fragmentation have serious consequences for species extinction as well as genetic diversity within a species. Random Amplified Polymorphic DNA (RAPD analysis was employed to assess the genetic diversity within and between four natural populations of M. lyra. Our results suggest that the genetic diversity varied from 0.21 to 0.26 with a mean of 0.11 to 0.13 (± SD. The mean Gst value of 0.15 was obtained from all four populations and estimated average Nm (1.41 showing gene flow between the populations. AMOVA analysis showed 88.96% within and 11.04% among the studied populations. Cluster analyses of RAPD phenotypes showed that specimens were not grouped by geographical origin. The genetic diversity found in the M. lyra population may be explained by its breeding behaviors. Though preliminary, the results indicate that all four populations should be considered to maintain the genetic diversity.

  1. QT/RR Coupling and Gender Differences

    Czech Academy of Sciences Publication Activity Database

    Halámek, Josef; Jurák, Pavel; Lipoldová, J.; Leinveber, Pavel

    2010-01-01

    Roč. 37, - (2010), s. 365-368 ISSN 0276-6574 R&D Projects: GA ČR GA102/08/1129 Institutional research plan: CEZ:AV0Z20650511 Keywords : THEW * QT/RR model * EXPDC Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering http://cinc.mit.edu/archives/2010/pdf/0365.pdf

  2. Þórr and wading

    DEFF Research Database (Denmark)

    Wills, Tarrin Jon

    2017-01-01

    Crossing rivers and boggy ground would have presented a number of dangers to early Scandinavians. There is a good deal of mythological evidence that Þórr is associated with the challenges of travelling by sea, as well as on various kinds of watery situations on land, such as rivers, lakes and bogs...... and marshes (as shown by runic inscriptions commemorating bridges and fords), and attempts an explanation of this relationship in terms of the mythological evidence....

  3. The complex case of V445 Lyr observed with Kepler: two Blazhko modulations, a non-radial mode, possible triple mode RR Lyrae pulsation, and more

    DEFF Research Database (Denmark)

    Guggenberger, E.; Kolenberg, K.; Nemec, J. M.

    2012-01-01

    Blazhko modulation, V445 Lyr also shows a rich spectrum of additional peaks in the frequency range between the fundamental pulsation and the first harmonic. Among those peaks, the second radial overtone could be identified, which, combined with a metallicity estimate of [Fe/H]=-2.0 dex from spectroscopy......, allowed to constrain the mass (0.55-0.65 M_sun) and luminosity (40-50 L_sun) of V445 Lyr through theoretical Petersen diagrams. A non-radial mode as well as possibly the first overtone are also excited. Furthermore, V445 Lyr shows signs of the period doubling phenomenon and a long term period change...

  4. The SuperWASP catalogue of 4963 RR Lyr stars: identification of 983 Blazhko effect candidates

    Science.gov (United States)

    Greer, P. A.; Payne, S. G.; Norton, A. J.; Maxted, P. F. L.; Smalley, B.; West, R. G.; Wheatley, P. J.; Kolb, U. C.

    2017-10-01

    Aims: We set out to compile a catalogue of RRab pulsating variables in the SuperWASP archive and identify candidate Blazhko effect objects within this catalogue. We analysed their light curves and power spectra for correlations in their common characteristics to further our understanding of the phenomenon. Methods: Pulsation periods were found for each SWASP RRab object using phase dispersion minimisation techniques. Low frequency periodic signals detected in the CLEAN power spectra of RRab stars were matched with modulation sidebands and combined with pairs of sidebands to produce a list of candidate Blazhko periods. A novel technique was used in an attempt to identify Blazhko effect stars by comparing scatter at different parts of the folded light curve. Pulsation amplitudes were calculated based on phase folded light curves. Results: The SuperWASP RRab catalogue consists of 4963 objects of which 3397 are previously unknown. We discovered 983 distinct candidates for Blazhko effect objects, 613 of these being previously unknown in the literature as RR Lyrae stars, and 894 are previously unknown to be Blazhko effect stars. Correlations were investigated between the scatter of points on the light curve, the periods and amplitudes of the objects' pulsations, and those of the Blazhko effect. Conclusions: A statistical analysis has been performed on a large population of Blazhko effect stars from the wide-field SuperWASP survey. No correlations were found between the Blazhko period and other parameters including the Blazhko amplitude, although we confirmed a lower rate of occurrence of the Blazhko effect in long pulsation period objects. Full Tables 1 and 2 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/607/A11

  5. In-flight performance of the solar UV radiometer LYRA/PROBA-2

    Science.gov (United States)

    Stockman, Y.; BenMoussa, A.; Dammasch, I.; Defise, J.-M.; Dominique, M.; Halain, J.-P.; Hochedez, J.-F.; Koller, S.; Schmutz, W.; Schühle, U.

    2017-11-01

    LYRA is a solar radiometer, part of the PROBA-2 micro-satellite payload (Fig. 1). The PROBA-2 [1] mission has been launched on 02 November 2009 with a Rockot launcher to a Sun-synchronous orbit at an altitude of 725 km. Its nominal operation duration is two years with possible extension of 2 years. PROBA-2 is a small satellite developed under an ESA General Support Technology Program (GSTP) contract to perform an in-flight demonstration of new space technologies and support a scientific mission for a set of selected instruments [2]. PROBA-2 host 17 technological demonstrators and 4 scientific instruments. The mission is tracked by the ESA Redu Mission Operation Center. One of the four scientific instruments is LYRA that monitors the solar irradiance at a high cadence (> 20 Hz) in four soft X-Ray to VUV large passbands: the "Lyman-Alpha" channel, the "Herzberg" continuum range, the "Aluminium" and "Zirconium" filter channels. The radiometric calibration is traceable to synchrotron source standards [3]. LYRA benefits from wide bandgap detectors based on diamond. It is the first space assessment of these revolutionary UV detectors for astrophysics. Diamond sensors make the instruments radiation-hard and solar-blind (insensitive to the strong solar visible light) and, therefore, visible light blocking filters become superfluous. To correlate the data of this new detector technology, silicon detectors with well known characteristics are also embarked. Due to the strict allocated mass and power budget (5 kg, 5W), and poor priority to the payload needs on such platform, an optimization and a robustness of the instrument was necessary. The first switch-on occured on 16 November 2009. Since then the instrument performances have been monitored and analyzed during the commissioning period. This paper presents the first-light and preliminary performance analysis.

  6. LRS Bianchi Type II Massive String Cosmological Models with Magnetic Field in Lyra's Geometry

    Directory of Open Access Journals (Sweden)

    Raj Bali

    2013-01-01

    Full Text Available Bianchi type II massive string cosmological models with magnetic field and time dependent gauge function ( in the frame work of Lyra's geometry are investigated. The magnetic field is in -plane. To get the deterministic solution, we have assumed that the shear ( is proportional to the expansion (. This leads to , where and are metric potentials and is a constant. We find that the models start with a big bang at initial singularity and expansion decreases due to lapse of time. The anisotropy is maintained throughout but the model isotropizes when . The physical and geometrical aspects of the model in the presence and absence of magnetic field are also discussed.

  7. QT/RR hysteresis as a function of RR excitation – implications for risk

    Czech Academy of Sciences Publication Activity Database

    Halámek, Josef; Jurák, Pavel; Somers, V. K.; Nykodým, J.; Leinveber, P.; Fráňa, P.; Eisenberger, M.; Kára, T.

    2005-01-01

    Roč. 4, č. 1 (2005), s. 98 [World Congress on Heart Disease - New Trends in Research, Diagnosis and Treatment /12./. 16.07.2005-19.07.2005, Vancouver] Institutional research plan: CEZ:AV0Z20650511 Keywords : ventricular repolarization * RR intervals Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery

  8. “O Farol do Bom Senso”: júri e ciência do direito penal em Roberto Lyra

    Directory of Open Access Journals (Sweden)

    Ricardo Sontag

    2014-06-01

    Full Text Available Este trabalho pretende analisar historicamente um dos tipos de argumentos expendidos por Roberto Lyra em defesa do júri. Segundo Lyra, existiam dois tipos básicos de argumentos contra o júri: os “técnico-jurídicos” e os “técnico-científicos”. Este trabalho pretende concentrar-se na oposição de Lyra aos argumentos “técnico-jurídicos”. Ao invés de buscar as origens distantes dos argumentos de Lyra, que poderiam remontar ao final do século XVIII e início do século XIX, procurou-se privilegiar um contexto histórico mais imediato, isto é, o dos debates em torno do papel da ciência jurídico-penal. Enquanto os esforços contra os argumentos “técnico-científicos” revelam uma divergência interna no âmbito do positivismo criminológico, a oposição aos argumentos “técnico-jurídicos” está vinculada aos embates de Lyra contra o tecnicismo jurídico-penal, que atribuía à aplicação precisa da lei positiva-estatal um papel que colocava em xeque o modo de funcionamento de grande parte da ciência do direito “bachaleresca” herdada do século XIX.

  9. RR-Interval variance of electrocardiogram for atrial fibrillation detection

    Science.gov (United States)

    Nuryani, N.; Solikhah, M.; Nugoho, A. S.; Afdala, A.; Anzihory, E.

    2016-11-01

    Atrial fibrillation is a serious heart problem originated from the upper chamber of the heart. The common indication of atrial fibrillation is irregularity of R peak-to-R-peak time interval, which is shortly called RR interval. The irregularity could be represented using variance or spread of RR interval. This article presents a system to detect atrial fibrillation using variances. Using clinical data of patients with atrial fibrillation attack, it is shown that the variance of electrocardiographic RR interval are higher during atrial fibrillation, compared to the normal one. Utilizing a simple detection technique and variances of RR intervals, we find a good performance of atrial fibrillation detection.

  10. Bianchi Type-III Cosmological Models in Lyra's Geometry in the Presence of Massive Scalar Field

    Science.gov (United States)

    Singh, J. K.; Rani, Sarita

    2015-02-01

    Spatially homogeneous and totally anisotropic Bianchi type-III cosmological models in the theory based on Lyra's geometry in Gauss normal gauge in the presence of an attractive massive scalar field have been investigated. To get the deterministic model in terms of cosmic time, it has been assumed that the expansion scalar Θ in the models is proportional to the shear scalar σ. Two models, one with variable deceleration parameter and another with constant deceleration parameter have been discussed. To discuss the model with constant deceleration parameter, we have used the special law of variation for Hubble's parameter proposed by (Berman Nuovo Cimento 74B, 184, 1983). The physical and geometrical properties of the models have been discussed. The energy conditions of the models are verified. It has been concluded that one of the universe models approaches to isotropy through the evolution of the universe, in some special cases.

  11. Reconstruction of the solar spectral UV irradiance for nowcasting of the middle atmosphere state on the basis of LYRA measurements

    Directory of Open Access Journals (Sweden)

    T. Egorova

    2008-06-01

    Full Text Available The LYRA instrument onboard ESA PROBA2 satellite will provide 6-hourly solar irradiance at the Lyman-alpha (121.6 nm and the Herzberg continuum (~200–220 nm wavelength range. Because the nowcasting of the neutral and ionic state of the middle atmosphere requires the solar irradiance for the wide spectral range (120–680 nm we have developed the statistical tool for the reconstruction of the full spectrum from the LYRA measurements. The accuracy of the reconstructed irradiance has been evaluated with 1-D transient radiative-convective model with neutral and ion chemistry using the daily solar spectral irradiance measured with SUSIM and SOLSTICE instruments onboard UARS satellite. We compared the results of transient 1-year long model simulations for 2000 driven by the observed and reconstructed solar irradiance and showed that the reconstruction of the full spectrum using linear regression equation based on the solar irradiance in two LYRA channels can be successfully used for nowcasting of the middle atmosphere. We have also identified conditions when the proposed approach does not yield spectral reconstruction with sufficient accuracy.

  12. Inheritance Patterns, Dominance and Cross-Resistance of Cry1Ab- and Cry1Ac-Selected Ostrinia furnacalis (Guenée

    Directory of Open Access Journals (Sweden)

    Tiantao Zhang

    2014-09-01

    Full Text Available Two colonies of Asian corn borer, Ostrinia furnacalis (Guenée, artificially selected from a Bt-susceptible colony (ACB-BtS for resistance to Cry1Ab (ACB-AbR and Cry1Ac (ACB-AcR toxins, were used to analyze inheritance patterns of resistance to Cry1 toxins. ACB-AbR and ACB-AcR evolved significant levels of resistance, with resistance ratios (RR of 39-fold and 78.8-fold to Cry1Ab and Cry1Ac, respectively. The susceptibility of ACB-AbR larvae to Cry1Ac and Cry1F toxins, which had not previously been exposed, were significantly reduced, being >113-fold and 48-fold, respectively. Similarly, susceptibility of ACB-AcR larvae to Cry1Ab and Cry1F were also significantly reduced (RR > nine-fold, RR > 18-fold, respectively, indicating cross-resistance among Cry1Ab, Cry1Ac, and Cry1F toxins. However, ACB-AbR and ACB-AcR larvae were equally susceptible to Cry1Ie as were ACB-BtS larvae, indicating no cross-resistance between Cry1Ie and Cry1Ab or Cry1Ac toxins; this may provide considerable benefits in preventing or delaying the evolution of resistance in ACB to Cry1Ab and Cry1Ac toxins. Backcrossing studies indicated that resistance to Cry1Ab toxin was polygenic in ACB-AbR, but monogenic in ACB-AcR, whilst resistance to Cry1Ac toxin was primarily monogenic in both ACB-AbR and ACB-AcR, but polygenic as resistance increased.

  13. Spectral of electrocardiographic RR intervals to indicate atrial fibrillation

    Science.gov (United States)

    Nuryani, Nuryani; Satrio Nugroho, Anto

    2017-11-01

    Atrial fibrillation is a serious heart diseases, which is associated on the risk of death, and thus an early detection of atrial fibrillation is necessary. We have investigated spectral pattern of electrocardiogram in relation to atrial fibrillation. The utilized feature of electrocardiogram is RR interval. RR interval is the time interval between a two-consecutive R peaks. A series of RR intervals in a time segment is converted to a signal with a frequency domain. The frequency components are investigated to find the components which significantly associate to atrial fibrillation. A segment is defined as atrial fibrillation or normal segments by considering a defined number of atrial fibrillation RR in the segment. Using clinical data of 23 patients with atrial fibrillation, we find that the frequency components could be used to indicate atrial fibrillation.

  14. Toy Models of Universe with an Effective Varying Λ-Term in Lyra Manifold

    Directory of Open Access Journals (Sweden)

    Martiros Khurshudyan

    2015-01-01

    Full Text Available Research on the accelerated expansion of our Universe captures a lot of attention. The dark energy (DE is a way to explain it. In this paper we will consider scalar field quintessence DE with ωDE>-1 EoS, where the dynamics of the DE models related to the dynamics of the scalar field. We are interested in the study of the behavior of the Universe in the presence of interacting quintessence DE models in Lyra manifold with a varying Λt. In a considered framework we also would like to propose a new form for Λt. We found that the models correspond to the transit Universe, which will enter the accelerated expansion phase and will remain there with a constant deceleration parameter q. We found also that the Λt is a decreasing function which takes a small positive value with Ωm≠0 and ΩQ→const dominating Ωm in the old Universe. Observational constraints are applied and causality issue via CS2 is discussed as a possible way to either reject or accept the models.

  15. The effect of temporal structure on rustling-sound detection in the gleaning bat, Megaderma lyra.

    Science.gov (United States)

    Hübner, M; Wiegrebe, L

    2003-05-01

    For a gleaning bat hunting prey from the ground, rustling sounds generated by prey movements are essential to invoke a hunting behaviour. The detection of prey-generated rustling sounds may depend heavily on the time structure of the prey-generated and the masking sounds due to their spectral similarity. Here, we systematically investigate the effect of the temporal structure on psychophysical rustling-sound detection in the gleaning bat, Megaderma lyra. A recorded rustling sound serves as the signal; the maskers are either Gaussian noise or broadband noise with various degrees of envelope fluctuations. Exploratory experiments indicate that the selective manipulation of the temporal structure of the rustling sound does not influence its detection in a Gaussian-noise masker. The results of the main experiment show, however, that the temporal structure of the masker has a strong and systematic effect on rustling-sound detection: When the width of irregularly spaced gaps in the masker exceeded about 0.3 ms, rustling-sound detection improved monotonically with increasing gap duration. Computer simulations of this experiment reveal that a combined detection strategy of spectral and temporal analysis underlies rustling-sound detection with fluctuating masking sounds.

  16. Exact solutions of bulk viscous with string cloud attached to strange quark matter for higher dimensional FRW universe in Lyra geometry

    Energy Technology Data Exchange (ETDEWEB)

    Çağlar, Halife, E-mail: hlfcglr@gmail.com [Çanakkale Onsekiz Mart University, Institute for Natural and Applied Sciences, Terzioğlu Campus, Çanakkale, 17020 (Turkey); Aygün, Sezgin, E-mail: saygun@comu.edu.tr [Çanakkale Onsekiz Mart University, Arts and Sciences Faculty, Department of Physics, Terzioğlu Campus, Çanakkale, 17020 (Turkey)

    2016-03-25

    In this study, we have investigated bulk viscous with strange quark matter attached to the string cloud for higher dimensional Friedman-Robertson-Walker (FRW) universe in Lyra geometry. By using varying deceleration parameter and conservation equations we have solved Einstein Field Equations (EFE’s) and obtained generalized exact solutions for our model. Also we have found that string is not survived for bulk viscous with strange quark matter attached to the string cloud in framework higher dimensional FRW universe in Lyra geometry. This result agrees with Kiran and Reddy, Krori et al, Sahoo and Mishra and Mohanty et al. in four and five dimensions.

  17. Exact solutions of bulk viscous with string cloud attached to strange quark matter for higher dimensional FRW universe in Lyra geometry

    International Nuclear Information System (INIS)

    Çağlar, Halife; Aygün, Sezgin

    2016-01-01

    In this study, we have investigated bulk viscous with strange quark matter attached to the string cloud for higher dimensional Friedman-Robertson-Walker (FRW) universe in Lyra geometry. By using varying deceleration parameter and conservation equations we have solved Einstein Field Equations (EFE’s) and obtained generalized exact solutions for our model. Also we have found that string is not survived for bulk viscous with strange quark matter attached to the string cloud in framework higher dimensional FRW universe in Lyra geometry. This result agrees with Kiran and Reddy, Krori et al, Sahoo and Mishra and Mohanty et al. in four and five dimensions.

  18. Evaluating autoimmunity markers (TPO Ab, Tg Ab and TM Ab in hypothyroid patients of Bushehr province

    Directory of Open Access Journals (Sweden)

    Iraj Nabipour

    2005-09-01

    Full Text Available Background: Chronic autoimmune thyroiditis (Hashimoto's Thyroiditis is the common cause of primary hypothyroidism in iodine sufficient countries. Iran is named an iodine sufficient country, in this century. Methods: A total of 88 hypothyroid patients, on suppressing dose of levothyroxine who were followed in a university endocrine disorder clinic were evaluated for serum thyroid autoimmunity markers: thyroid peroxidase antibody (TPO Ab, thyroglobulin antibody (Tg Ab and thyroid microsomal antibody (TM Ab using ELISA method. Results: The prevalence of TPO Ab, Tg Ab and TM Ab were 73.9%, 45.5% and 71.6%, respectively. Among the patients with high level of TPO Ab (> 75 u/ml, 45.3% had grade 1 or 2 of goiter (P< 0.05. Conclusion: Autoimmune thyroid disease (Hashimoto's thyroiditis is the most common cause of hypothyroidism in Bushehr province.

  19. The Globular Cluster NGC 6402 (M14). II. Variable Stars

    Science.gov (United States)

    Contreras Peña, C.; Catelan, M.; Grundahl, F.; Stephens, A. W.; Smith, H. A.

    2018-03-01

    We present time-series BVI photometry for the Galactic globular cluster NGC 6402 (M14). The data consist of ∼137 images per filter, obtained using the 0.9 and 1.0 m SMARTS telescopes at the Cerro Tololo Inter-American Observatory. The images were obtained during two observing runs in 2006–2007. The image-subtraction package ISIS, along with DAOPHOT II/ALLFRAME, was used to perform crowded-field photometry and search for variable stars. We identified 130 variables, eight of which are new discoveries. The variable star population is comprised of 56 ab-type RR Lyrae stars, 54 c-type RR Lyrae, 6 type II Cepheids, 1 W UMa star, 1 detached eclipsing binary, and 12 long-period variables. We provide Fourier decomposition parameters for the RR Lyrae, and discuss the physical parameters and photometric metallicity derived therefrom. The M14 distance modulus is also discussed, based on different approaches for the calibration of the absolute magnitudes of RR Lyrae stars. The possible presence of second-overtone RR Lyrae in M14 is critically addressed, with our results arguing against this possibility. By considering all of the RR Lyrae stars as members of the cluster, we derive =0.589 {{d}}{{a}}{{y}}{{s}}. This, together with the position of the RR Lyrae stars of both Bailey types in the period–amplitude diagram, suggests an Oosterhoff-intermediate classification for the cluster. Such an intermediate Oosterhoff type is much more commonly found in nearby extragalactic systems, and we critically discuss several other possible indications that may point to an extragalactic origin for this cluster. Based on observations obtained with the 0.9 m and 1 m telescopes at the Cerro Tololo Inter-American Observatory, Chile, operated by the SMARTS consortium.

  20. AB Manpower Plan 2007

    CERN Document Server

    Myers, Stephen

    2007-01-01

    The present exercise is not as such a "manpower plan" but a purely budgetary comparison of known plus requested resources with the known commitments over the period 2007-2012. From a purely budgetary point of view, AB will have the capacity to maintain all those recently hired staff who fulfill the criteria for long term employment at CERN. Following this budgetary exercise, AB proposes to perform a CERN-wide staff work plan so as to compare the manpower available to the quantity of work to be done in the totality of the work-packages. If there is a significant mismatch between these two quantities then we propose the following measures which would create personnel economies and allow us to redress the mismatch by increased recruitment: a new job severance scheme; CERN restructuring; use of the new CERN-ITER agreement; more flexibility in transfers from Materials to Personnel budgets. Failing this a re-examination of possible closure of lower priority facilities may be needed.

  1. EVIDENCE FOR A MILKY WAY TIDAL STREAM REACHING BEYOND 100 kpc

    Energy Technology Data Exchange (ETDEWEB)

    Drake, A. J.; Djorgovski, S. G.; Graham, M. J.; Mahabal, A.; Donalek, C.; Williams, R. [California Institute of Technology, 1200 E. California Blvd., CA 91225 (United States); Catelan, M.; Torrealba, G. [Pontificia Universidad Catolica de Chile, Departamento de Astronomia y Astrofisica, Facultad de Fisica, Av. Vicuna Mackena 4860, 782-0436 Macul, Santiago (Chile); Prieto, J. L. [Department of Astronomy, Princeton University, 4 Ivy Lane, Princeton, NJ 08544 (United States); Larson, S.; Christensen, E.; Beshore, E. [Department of Planetary Sciences, University of Arizona, Lunar and Planetary Laboratory, 1629 E. University Blvd., Tucson AZ 85721 (United States)

    2013-03-10

    We present the analysis of 1207 RR Lyrae found in photometry taken by the Catalina Survey's Mount Lemmon telescope. By combining accurate distances for these stars with measurements for {approx}14,000 type-ab RR Lyrae from the Catalina Schmidt telescope, we reveal an extended association that reaches Galactocentric distances beyond 100 kpc and overlaps the Sagittarius stream system. This result confirms earlier evidence for the existence of an outer halo tidal stream resulting from a disrupted stellar system. By comparing the RR Lyrae source density with that expected based on halo models, we find the detection has {approx}8{sigma} significance. We investigate the distances, radial velocities, metallicities, and period-amplitude distribution of the RR Lyrae. We find that both radial velocities and distances are inconsistent with current models of the Sagittarius stream. We also find tentative evidence for a division in source metallicities for the most distant sources. Following prior analyses, we compare the locations and distances of the RR Lyrae with photometrically selected candidate horizontal branch stars and find supporting evidence that this structure spans at least 60 Degree-Sign of the sky. We investigate the prospects of an association between the stream and the unusual globular cluster NGC 2419.

  2. Down regulation of a gene for cadherin, but not alkaline phosphatase, associated with Cry1Ab resistance in the sugarcane borer Diatraea saccharalis.

    Directory of Open Access Journals (Sweden)

    Yunlong Yang

    Full Text Available The sugarcane borer, Diatraea saccharalis, is a major target pest of transgenic corn expressing Bacillus thuringiensis (Bt proteins (i.e., Cry1Ab in South America and the mid-southern region of the United States. Evolution of insecticide resistance in such target pests is a major threat to the durability of transgenic Bt crops. Understanding the pests' resistance mechanisms will facilitate development of effective strategies for delaying or countering resistance. Alterations in expression of cadherin- and alkaline phosphatase (ALP have been associated with Bt resistance in several species of pest insects. In this study, neither the activity nor gene regulation of ALP was associated with Cry1Ab resistance in D. saccharalis. Total ALP enzymatic activity was similar between Cry1Ab-susceptible (Cry1Ab-SS and -resistant (Cry1Ab-RR strains of D. saccharalis. In addition, expression levels of three ALP genes were also similar between Cry1Ab-SS and -RR, and cDNA sequences did not differ between susceptible and resistant larvae. In contrast, altered expression of a midgut cadherin (DsCAD1 was associated with the Cry1Ab resistance. Whereas cDNA sequences of DsCAD1 were identical between the two strains, the transcript abundance of DsCAD1 was significantly lower in Cry1Ab-RR. To verify the involvement of DsCAD1 in susceptibility to Cry1Ab, RNA interference (RNAi was employed to knock-down DsCAD1 expression in the susceptible larvae. Down-regulation of DsCAD1 expression by RNAi was functionally correlated with a decrease in Cry1Ab susceptibility. These results suggest that down-regulation of DsCAD1 is associated with resistance to Cry1Ab in D. saccharalis.

  3. Genetic divergence of roundup ready (RR) soybean cultivars ...

    African Journals Online (AJOL)

    The aim of this study was to estimate the genetic diversity in 74 RR soybean cultivars from different Brazilian breeding programs. Analyzes were based on multivariate statistical techniques from phenotypic characteristics and microsatellite molecular markers (SSR). Ten agronomic traits were used in the analysis of the ...

  4. Menopause, hormone replacement and RR and QT modulation during sleep

    Czech Academy of Sciences Publication Activity Database

    Lanfranchi, P. A.; Gosselin, N.; Kára, T.; Jurák, Pavel; Somers, V. K.; Denesle, R.; Petit, D.; Carrier, J.; Nadeau, R.; Montplaisir, J.

    2005-01-01

    Roč. 6, č. 6 (2005), s. 561-566 ISSN 1389-9457 R&D Projects: GA ČR(CZ) GA102/05/0402 Keywords : Sleep * Menopause * RR interval * QT interval * Gender * Hormones Subject RIV: FS - Medical Facilities ; Equipment Impact factor: 2.711, year: 2005

  5. Heartbeat Classification Using Normalized RR Intervals and Morphological Features

    Directory of Open Access Journals (Sweden)

    Chun-Cheng Lin

    2014-01-01

    Full Text Available This study developed an automatic heartbeat classification system for identifying normal beats, supraventricular ectopic beats, and ventricular ectopic beats based on normalized RR intervals and morphological features. The proposed heartbeat classification system consists of signal preprocessing, feature extraction, and linear discriminant classification. First, the signal preprocessing removed the high-frequency noise and baseline drift of the original ECG signal. Then the feature extraction derived the normalized RR intervals and two types of morphological features using wavelet analysis and linear prediction modeling. Finally, the linear discriminant classifier combined the extracted features to classify heartbeats. A total of 99,827 heartbeats obtained from the MIT-BIH Arrhythmia Database were divided into three datasets for the training and testing of the optimized heartbeat classification system. The study results demonstrate that the use of the normalized RR interval features greatly improves the positive predictive accuracy of identifying the normal heartbeats and the sensitivity for identifying the supraventricular ectopic heartbeats in comparison with the use of the nonnormalized RR interval features. In addition, the combination of the wavelet and linear prediction morphological features has higher global performance than only using the wavelet features or the linear prediction features.

  6. Semeadura do híbrido Lyra de mamona (Ricinus communis L. sob plantio direto Seeding of castor bean (Ricinus communis L. hybrid Lyra in no-tillage system

    Directory of Open Access Journals (Sweden)

    Nilza Patrícia Ramos

    2008-04-01

    Full Text Available A semeadura mecanizada da mamona (Ricinus communis L. pode reduzir o tempo de operação e os custos associados à mão-de-obra, porém a escassez de informações nesta área tem prejudicado a adoção correta desta tecnologia. Assim, objetivou-se com esse trabalho verificar a regularidade da distribuição longitudinal de sementes do híbrido Lyra de mamona, em área de plantio direto e sua relação com rendimento de grãos; bem como a viabilidade da aplicação de cartas de controle para a avaliação do processo de semeadura, nesta cultura. O ensaio foi conduzido em área comercial de produção de grãos de mamona sob plantio direto, sendo avaliadas: distribuição longitudinal, porcentagens de espaçamentos normais, falhos e duplos na linha, número de planta por metro linear, altura de plantas, altura e comprimento do racemo primário e rendimento de grãos. Utilizou-se a estatística descritiva, a análise de correlações e as cartas de controle para a avaliação dos parâmetros propostos. Há necessidade de refinamento nas regulagens de semeadoras-adubadoras de precisão para a semeadura do híbrido Lyra de mamona, em áreas de plantio direto; a distribuição longitudinal de sementes de mamona influencia vários parâmetros fitotécnicos, incluindo o rendimento de grãos; a aplicação da carta de controle é uma ferramenta eficiente para a avaliação do processo de semeadura da mamona.The mechanized sowing of castor bean (Ricinus communis L. can reduce the operation time and the costs associated to labor, however the privation of information in this area have damaged the correct adoption of this technology. Thus, the research had as an aim to verify the regularity of longitudinal distribution of hybrid Lyra castor bean seeds, in a no-tillage system area, and its relationship with yield; and the viability of control charts for evaluation of sowing in this crop. The essay was carded out in a commercial area of grain production in no

  7. ECG R-R peak detection on mobile phones.

    Science.gov (United States)

    Sufi, F; Fang, Q; Cosic, I

    2007-01-01

    Mobile phones have become an integral part of modern life. Due to the ever increasing processing power, mobile phones are rapidly expanding its arena from a sole device of telecommunication to organizer, calculator, gaming device, web browser, music player, audio/video recording device, navigator etc. The processing power of modern mobile phones has been utilized by many innovative purposes. In this paper, we are proposing the utilization of mobile phones for monitoring and analysis of biosignal. The computation performed inside the mobile phone's processor will now be exploited for healthcare delivery. We performed literature review on RR interval detection from ECG and selected few PC based algorithms. Then, three of those existing RR interval detection algorithms were programmed on Java platform. Performance monitoring and comparison studies were carried out on three different mobile devices to determine their application on a realtime telemonitoring scenario.

  8. Response of Haloalkaliphilic Archaeon Natronococcus Jeotgali RR17 to Hypergravity

    Science.gov (United States)

    Thombre, Rebecca S.; Bhalerao, Aniruddha R.; Shinde, Vinaya D.; Dhar, Sunil Kumar; Shouche, Yogesh S.

    2017-06-01

    The survival of archaeabacteria in extreme inhabitable environments on earth that challenge organismic survival is ubiquitously known. However, the studies related to the effect of hypergravity on the growth and proliferation of archaea are unprecedented. The survival of organisms in hypergravity and rocks in addition to resistance to cosmic radiations, pressure and other extremities is imperative to study the possibilities of microbial travel between planets and endurance in hyperaccelerative forces faced during ejection of rocks from planets. The current investigation highlights the growth of an extremophilic archaeon isolated from a rocky substrate in hypergravity environment. The haloalkaliphilic archaeon, Natronococcus jeotgali RR17 was isolated from an Indian laterite rock, submerged in the Arabian sea lining Coastal Maharashtra, India. The endolithic haloarchaeon was subjected to hypergravity from 56 - 893 X gusing acceleration generated by centrifugal rotation. The cells of N. jeotgali RR17 proliferated and demonstrated good growth in hypergravity (223 X g). This is the first report on isolation of endolithic haloarchaeon N. jeotgali RR17 from an Indian laterite rock and its ability to proliferate in hypergravity. The present study demonstrates the ability of microbial life to survive and proliferate in hypergravity. Thus the inability of organismic growth in hypergravity may no longer be a limitation for astrobiology studies related to habitability of substellar objects, brown dwarfs and other planetary bodies in the universe besides planet earth.

  9. Identification of atrial fibrillation using electrocardiographic RR-interval difference

    Science.gov (United States)

    Eliana, M.; Nuryani, N.

    2017-11-01

    Automated detection of atrial fibrillation (AF) is an interesting topic. It is an account of very dangerous, not only as a trigger of embolic stroke, but it’s also related to some else chronical disease. In this study, we analyse the presence of AF by determining irregularities of RR-interval. We utilize the interval comparison to measure the degree of irregularities of RR-interval in a defined segment. The series of RR-interval is segmented with the length of 10 of them. In this study, we use interval comparison for the method. We were comparing all of the intervals there each other. Then we put the threshold to define the low difference and high difference (δ). A segment is defined as AF or Normal Sinus by the number of high δ, so we put the tolerance (β) of high δ there. We have used this method to test the 23 patients data from MIT-BIH. Using the approach and the clinical data we find accuracy, sensitivity, and specificity of 84.98%, 91.99%, and 77.85% respectively.

  10. Mobility and the Modern Intellectual: Translated Images from Early 20th-Century Literary Works in Spanish by Carmen Lyra and Luisa Luisi

    Directory of Open Access Journals (Sweden)

    Laura Kanost

    2018-02-01

    Full Text Available This essay juxtaposes original translations of contrasting images from the novel En una silla de ruedas [In a Wheelchair] by Costa Rican writer Carmen Lyra and Poemas de la inmovilidad [Poems of Immobility] by Uruguayan writer Luisa Luisi to reveal how representations of intellectuals who are paralyzed might complicate discourses of the artist, social hygiene, and eugenics in early 20th-century Spanish America. Lyra portrays her protagonist's paralysis as a tragedy, but his disability is also the source of social mobility that allows the novel to depict marginalized members of Costa Rican society. Luisi contests modernista aesthetics of perfect forms, countering with a multifaceted exploration of inner space enabled by physical stillness. Through their depictions of hospitals, asylums, and sanitariums, both writers bear witness to bodies the modernizing project would prefer to hide, and imagine alternative forms of progress.

  11. Edu Lobo e Carlos Lyra: O Nacional e o Popular na Canção de Protesto (Os Anos 60

    Directory of Open Access Journals (Sweden)

    Arnaldo Daraya Contier

    1998-01-01

    Full Text Available Trata-se de um estudo sobre as possíveis conexões entre a canção de protesto (Edu Lobo, Carlos Lyra e os discursos do CPC durante os anos 60. As criações artísticas são analisadas com vistas a captar os vínculos entre o nacional-popular na canção brasileira e o impressionismo (C. Debussy, o cool-jazz (Miles Davis, Rodgers and Hart, Heitor Villa-Lobos (modernismo, Waldemar Henrique.This is a study if the possible connections between the protest song (Edu Lobo, Carlos Lyra and the CPC discourses in the 1960s. The artistics creations are analysed with a view to pointing out the ties between the national-popular in Brazilian song and the impressionism (C. Debussy, the cool-jazz (Miles Davis, Rodgers and Hart, Heitor Villa-Lobos (modernism, Waldemar Henrique.

  12. 77 FR 27085 - R.R. Donnelley, Inc., Bloomsburg, PA; Notice of Negative Determination on Reconsideration

    Science.gov (United States)

    2012-05-08

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-80,485] R.R. Donnelley, Inc... workers of R.R. Donnelley, Inc., Bloomsburg, Pennsylvania (subject firm). The Department's Notice of... eligibility to apply for worker adjustment assistance for workers and former workers of R.R. Donnelley, Inc...

  13. A Probabilistic Approach to Fitting Period–luminosity Relations and Validating Gaia Parallaxes

    Energy Technology Data Exchange (ETDEWEB)

    Sesar, Branimir; Fouesneau, Morgan; Bailer-Jones, Coryn A. L.; Gould, Andy; Rix, Hans-Walter [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Price-Whelan, Adrian M., E-mail: bsesar@mpia.de [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2017-04-01

    Pulsating stars, such as Cepheids, Miras, and RR Lyrae stars, are important distance indicators and calibrators of the “cosmic distance ladder,” and yet their period–luminosity–metallicity (PLZ) relations are still constrained using simple statistical methods that cannot take full advantage of available data. To enable optimal usage of data provided by the Gaia mission, we present a probabilistic approach that simultaneously constrains parameters of PLZ relations and uncertainties in Gaia parallax measurements. We demonstrate this approach by constraining PLZ relations of type ab RR Lyrae stars in near-infrared W 1 and W 2 bands, using Tycho- Gaia Astrometric Solution (TGAS) parallax measurements for a sample of ≈100 type ab RR Lyrae stars located within 2.5 kpc of the Sun. The fitted PLZ relations are consistent with previous studies, and in combination with other data, deliver distances precise to 6% (once various sources of uncertainty are taken into account). To a precision of 0.05 mas (1 σ ), we do not find a statistically significant offset in TGAS parallaxes for this sample of distant RR Lyrae stars (median parallax of 0.8 mas and distance of 1.4 kpc). With only minor modifications, our probabilistic approach can be used to constrain PLZ relations of other pulsating stars, and we intend to apply it to Cepheid and Mira stars in the near future.

  14. Cross-resistance to purified Bt proteins, Bt corn and Bt cotton in a Cry2Ab2-corn resistant strain of Spodoptera frugiperda.

    Science.gov (United States)

    Yang, Fei; Kerns, David L; Head, Graham P; Price, Paula; Huang, Fangneng

    2017-12-01

    Gene-pyramiding by combining two or more dissimilar Bacillus thuringiensis (Bt) proteins into a crop has been used to delay insect resistance. The durability of gene-pyramiding can be reduced by cross-resistance. Fall armyworm, Spodoptera frugiperda, is a major target pest of the Cry2Ab2 protein used in pyramided Bt corn and cotton. Here, we provide the first experimental evaluation of cross-resistance in S. frugiperda selected with Cry2Ab2 corn to multiple Bt sources including purified Bt proteins, Bt corn and Bt cotton. Concentration - response bioassays showed that resistance ratios for Cry2Ab2-resistant (RR) relative to Cry2Ab2-susceptible (SS) S. frugiperda were -1.4 for Cry1F, 1.2 for Cry1A.105, >26.7 for Cry2Ab2, >10.0 for Cry2Ae and -1.1 for Vip3A. Larvae of Cry2Ab2-heterozygous (RS), SS and RR S. frugiperda were all susceptible to Bt corn and Bt cotton containing Cry1 (Cry1F or Cry1A.105) and/or Vip3A proteins. Pyramided Bt cotton containing Cry1Ac + Cry2Ab2 or Cry1Ab + Cry2Ae were also effective against SS and RS, but not RR. These findings suggest that Cry2Ab2-corn-selected S. frugiperda is not cross-resistant to Cry1F, Cry1A.105 or Vip3A protein, or corn and cotton plants containing these Bt proteins, but it can cause strong cross-resistance to Cry2Ae and Bt crops expressing similar Bt proteins. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  15. Lignification of the plant and seed quality of RR soybeans sprayed with herbicide glyphosate

    Directory of Open Access Journals (Sweden)

    Cristiane Fortes Gris

    2013-04-01

    Full Text Available Differences in levels of lignin in the plant between conventional and transgenic cultivars RR has been reported by several authors, however, there are few studies evaluating the influence of spraying of glyphosate on the lignin in the plant and RR soybean seeds. The aim of this study was to evaluate the physiological quality of RR transgenic soybean seeds and the lignin contents of plants sprayed with the herbicide glyphosate. The assays were conducted both in greenhouse and field in the municipality of Lavras, MG, in the agricultural year 2007/08. The experiment was arranged in a splitplot design with four replicates, considering the treatments hand weeding and herbicide glyphosate as plots, and five RR soybean cultivars (BRS 245 RR, BRS 247 RR, Valiosa RR, Silvânia RR and Baliza RR as splitplots. In the greenhouse, the cultivars tested were BRS 245 RR and Valiosa RR in a randomized block design with four replicates. The sprayings were carried out at stages V3, V7 and early R5 (3L/ha. The 1000 seed weight, mechanical injury, germination and germination velocity index, emergence velocity index, accelerated aging, electrical conductivity and water soaking seed test, lignin content in the seed coat, in the stem and legumes were determined. The spraying of glyphosate herbicide, in greenhouse and field, did not alter the physiological quality of seeds and the lignin contents in the plant.

  16. Ab-initio ZORA calculations

    NARCIS (Netherlands)

    Faas, S.; Snijders, Jaap; van Lenthe, J.H.; HernandezLaguna, A; Maruani, J; McWeeny, R; Wilson, S

    2000-01-01

    In this paper we present the first application of the ZORA (Zeroth Order Regular Approximation of the Dirac Fock equation) formalism in Ab Initio electronic structure calculations. The ZORA method, which has been tested previously in the context of Density Functional Theory, has been implemented in

  17. The Globular Cluster NGC 6402 (M14). II. Variable Stars

    DEFF Research Database (Denmark)

    Contreras Peña, C.; Catelan, M.; Grundahl, F.

    2018-01-01

    approaches for the calibration of the absolute magnitudes of RR Lyrae stars. The possible presence of second-overtone RR Lyrae in M14 is critically addressed, with our results arguing against this possibility. By considering all of the RR Lyrae stars as members of the cluster, we derive =0.589 {{d...

  18. CDKN2A/B

    Science.gov (United States)

    Kong, Yahui; Sharma, Rohit B; Ly, Socheata; Stamateris, Rachel E; Jesdale, William M; Alonso, Laura C

    2018-02-06

    Genome-wide association studies link the CDKN2A/B locus with T2D risk, but mechanisms increasing risk remain unknown. The CDKN2A/B locus encodes cell cycle inhibitors p14 , p15 , and p16, MTAP, and ANRIL , a lncRNA. The goal of this study was to determine whether CDKN2A/B T2D risk-SNPs impact locus gene expression, insulin secretion, or beta cell proliferation, in human islets. Islets from non-diabetic donors (n=95) were tested for SNP genotype ( rs10811661 , rs2383208 , rs564398 , rs10757283 ), gene expression ( p14 , p15 , p16 , MTAP , ANRIL , PCNA , KI67 , CCND2 ), insulin secretion (n=61) and beta cell proliferation (n=47). Intriguingly, locus genes were co-regulated in islets in two physically overlapping cassettes: p14 - p16-ANRIL , which increased with age, and MTAP - p15 , which did not. Risk-alleles at rs10811661 and rs2383208 were differentially associated with expression of ANRIL , but not p14 , p15, p16 or MTAP , in age-dependent fashion, such that younger homozygous-risk donors had higher ANRIL expression, equivalent to older donor levels. We identified several risk-SNP haplotype combinations that may impact locus gene expression, suggesting possible mechanisms by which SNPs impact locus biology. Risk-allele carriers at ANRIL coding SNP rs564398 had reduced beta cell proliferation index. In conclusion, CDKN2A/B locus SNPs may impact T2D risk by modulating islet gene expression and beta cell proliferation. © 2018 by the American Diabetes Association.

  19. Ventricular cycle length characteristics estimative of prolonged RR interval during atrial fibrillation.

    Science.gov (United States)

    Ciaccio, Edward J; Biviano, Angelo B; Gambhir, Alok; Einstein, Andrew J; Garan, Hasan

    2014-03-01

    When atrial fibrillation (AF) is incessant, imaging during a prolonged ventricular RR interval may improve image quality. It was hypothesized that long RR intervals could be predicted from preceding RR values. From the PhysioNet database, electrocardiogram RR intervals were obtained from 74 persistent AF patients. An RR interval lengthened by at least 250 ms beyond the immediately preceding RR interval (termed T0 and T1, respectively) was considered prolonged. A two-parameter scatterplot was used to predict the occurrence of a prolonged interval T0. The scatterplot parameters were: (1) RR variability (RRv) estimated as the average second derivative from 10 previous pairs of RR differences, T13-T2, and (2) Tm-T1, the difference between Tm, the mean from T13 to T2, and T1. For each patient, scatterplots were constructed using preliminary data from the first hour. The ranges of parameters 1 and 2 were adjusted to maximize the proportion of prolonged RR intervals within range. These constraints were used for prediction of prolonged RR in test data collected during the second hour. The mean prolonged event was 1.0 seconds in duration. Actual prolonged events were identified with a mean positive predictive value (PPV) of 80% in the test set. PPV was >80% in 36 of 74 patients. An average of 10.8 prolonged RR intervals per 60 minutes was correctly identified. A method was developed to predict prolonged RR intervals using two parameters and prior statistical sampling for each patient. This or similar methodology may help improve cardiac imaging in many longstanding persistent AF patients. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.

  20. RR Tel: Getting Under the Flux Limit: An Observation with FUSE

    Science.gov (United States)

    Sonnenborn, George (Technical Monitor); Kenyon, Scott J.

    2004-01-01

    The goal of this program is to acquire a FUSE spectrum of the symbiotic binary RR Tel. With these data, we plan to derive improved constraints on the hot component, the nebula, and perhaps the red giant wind. Based on results from AG Dra, we should also be able to use some line detections to improve atomic parameters for high ionization emission lines. This results would benefit the general FUSE community. As of this writing, the FUSE observation of RR Tel has not been made. Because RR Tel is a very bright UV source, the FUSE team is assessing the likelihood that RR Tel will have an adverse affect on the instrument.

  1. Computer control of ET-RR-1 hot cell manipulators

    International Nuclear Information System (INIS)

    Effat, A.M.; Rahman, F.A.

    1990-01-01

    The hot cell designed for remote handling of radioactive materials are, in effect, integral systems of safety devices for attaining adequate radiological protection for the operating personnel. Their operation involve potential hazards that are sometimes of great magnitude. The effect of an incident or accident could thus be fatal. some of these incident are due to the collision of the manipulator slave side with the radioactive objectives. Therefore in order to minimize the probability of such type of incidents, the movement of the manipulators is suggested (in the present investigation) to be kept under computer control. A model have been developed to control the movement of the hot cell manipulators in the slave side for Egypt first research reactor ET-RR-1, specially in the hidden sectors. The model is based on the use of a microprocessor and some accessories fixed to the manipulators slave side in a special manner such that it prevents the manipulator from colliding with radioactive objects. This is achieved by a signal transmitted to a specially designed brake which controls the movement of the upper arm of the manipulator master side. The hardware design of the model as well as the software are presented in details

  2. AIREKMOD-RR, Reactivity Transients in Nuclear Research Reactors

    International Nuclear Information System (INIS)

    Baggoura, B.; Mazrou, H.

    2001-01-01

    1 - Description of program or function: AIREMOD-RR is a point kinetics code which can simulate fast transients in nuclear research reactor cores. It can also be used for theoretical reactor dynamics studies. It is used for research reactor kinetic analysis and provides a point neutron kinetic capability. The thermal hydraulic behavior is governed by a one-dimensional heat balance equation. The calculations are restricted to a single equivalent unit cell which consists of fuel, clad and coolant. 2 - Method of solution: For transient reactor kinetic calculations a modified Runge Kutta numerical method is used. The external reactivity insertion, specified as a function of time, is converted in dollar ($) unit. The neutron density, energy release and feedback variables are given at each time step. The two types of reactivity feedback considered are: Doppler effect and moderator effect. A new expression for the reactivity dependence on the feedback variables has been introduced in the present version of the code. The feedback reactivities are fitted in power series expression. 3 - Restrictions on the complexity of the problem: The number of delayed neutron groups and the total number of equations are limited only by computer storage capabilities. - Coolant is always in liquid phase. - Void reactivity feedback is not considered

  3. Thermo-Mechanical Fatigue Crack Growth of RR1000

    Directory of Open Access Journals (Sweden)

    Christopher John Pretty

    2017-01-01

    Full Text Available Non-isothermal conditions during flight cycles have long led to the requirement for thermo-mechanical fatigue (TMF evaluation of aerospace materials. However, the increased temperatures within the gas turbine engine have meant that the requirements for TMF testing now extend to disc alloys along with blade materials. As such, fatigue crack growth rates are required to be evaluated under non-isothermal conditions along with the development of a detailed understanding of related failure mechanisms. In the current work, a TMF crack growth testing method has been developed utilising induction heating and direct current potential drop techniques for polycrystalline nickel-based superalloys, such as RR1000. Results have shown that in-phase (IP testing produces accelerated crack growth rates compared with out-of-phase (OOP due to increased temperature at peak stress and therefore increased time dependent crack growth. The ordering of the crack growth rates is supported by detailed fractographic analysis which shows intergranular crack growth in IP test specimens, and transgranular crack growth in 90° OOP and 180° OOP tests. Isothermal tests have also been carried out for comparison of crack growth rates at the point of peak stress in the TMF cycles.

  4. AP calculus AB/BC

    CERN Document Server

    Schwartz, Stu

    2013-01-01

    All Access for the AP® Calculus AB & BC Exams Book + Web + Mobile Everything you need to prepare for the Advanced Placement® exam, in a study system built around you! There are many different ways to prepare for an Advanced Placement® exam. What's best for you depends on how much time you have to study and how comfortable you are with the subject matter. To score your highest, you need a system that can be customized to fit you: your schedule, your learning style, and your current level of knowledge. This book, and the free online tools that come with it, will help you personalize your AP® Cal

  5. ABS: Sequence alignment by scanning

    KAUST Repository

    Bonny, Mohamed Talal

    2011-08-01

    Sequence alignment is an essential tool in almost any computational biology research. It processes large database sequences and considered to be high consumers of computation time. Heuristic algorithms are used to get approximate but fast results. We introduce fast alignment algorithm, called Alignment By Scanning (ABS), to provide an approximate alignment of two DNA sequences. We compare our algorithm with the well-known alignment algorithms, the FASTA (which is heuristic) and the \\'Needleman-Wunsch\\' (which is optimal). The proposed algorithm achieves up to 76% enhancement in alignment score when it is compared with the FASTA Algorithm. The evaluations are conducted using different lengths of DNA sequences. © 2011 IEEE.

  6. The CoRR hypothesis for genes in organelles.

    Science.gov (United States)

    Allen, John F

    2017-12-07

    Chloroplasts and mitochondria perform energy transduction in photosynthesis and respiration. These processes can be described in physico-chemical terms with no obvious requirement for co-located genetic systems, separat from those of the rest of the cell. Accordingly, biochemists once tended to regard endosymbiosis as untestable evolutionary speculation. Lynn Sagan's seminal 1967 paper "On the Origin of Mitosing Cells" outlined the evolution of eukaryotic cells by endosymbiosis of prokaryotes. The endosymbiont hypothesis is consistent with presence of DNA in chloroplasts and mitochondria, but does not assign it a function. Biochemistry and molecular biology now show that Sagan's proposal has an explanatory reach far beyond that originally envisaged. Prokaryotic origins of photosynthetic and respiratory mechanisms are apparent in protein structural insights into energy coupling. Genome sequencing confirms the underlying, prokaryotic architecture of chloroplasts and mitochondria and illustrates the profound influence of the original mergers of their ancestors' genes and proteins with those of their host cells. Peter Mitchell's 1961 chemiosmotic hypothesis applied the concept of vectorial catalysis that underlies biological energy transduction and cell structure, function, and origins. Continuity of electrical charge separation and membrane sidedness requires compartments within compartments, together with intricate mechanisms for transport within and between them. I suggest that the reason for the persistence of distinct genetic systems within bioenergetic organelles is the selective advantage of subcellular co-location of specific genes with their gene products. Co-location for Redox Regulation - CoRR - provides for a dialogue between chemical reduction-oxidation and the action of genes encoding its protein catalysts. These genes and their protein products are in intimate contact, and cannot be isolated from each other without loss of an essential mechanism of

  7. Altered relationship between R-R interval and R-R interval variability in endurance athletes with overtraining syndrome.

    Science.gov (United States)

    Kiviniemi, A M; Tulppo, M P; Hautala, A J; Vanninen, E; Uusitalo, A L T

    2014-04-01

    Autonomic dysfunction decreases within-subject correlation between R-R interval length (RRi) and vagally mediated RRi variability in cardiac disease. We tested the hypothesis that overtraining syndrome (OTS) may also weaken this relationship. Nine OTS and 10 control endurance athletes underwent 24-h electrocardiogram monitoring, which was repeated in eight OTS and nine control athletes after 6 months, when two OTS athletes still had symptoms of OTS. The power of high-frequency (HF) oscillations of RRi was analyzed in 5-min epochs over the whole recording. Quadratic regression was performed between 5-min values of RRi and log-transformed (ln) HF to obtain R(2) for each recording. The relationship between RRi and HFln was higher in the OTS athletes than controls [R(2): 0.87 (90% confidence interval, CI: 0.84-0.89) vs 0.78 (90% CI: 0.72-0.84); P = 0.034; effect size = 1.22]. Large decrease in R(2) was observed in six recovered OTS athletes after 6 months follow-up [ΔR(2): -0.12 (90% CI: -0.25-0.01); P = 0.11; effect size = 1.44] with no changes in the controls. Mean values of RRi and its variability did not differ between the groups. The within-subject correlation between RRi and vagally mediated RRi variability was stronger in endurance athletes with OTS compared with controls. The present findings may improve the detection of OTS and recovery from OTS in endurance athletes. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Co-continuous polycarbonate/ABS blends

    NARCIS (Netherlands)

    Inberg, J.P.F.; Gaymans, R.J.

    2002-01-01

    Co-continuous PC/ABS (50/50) blends were studied with a variable polybutadiene (PB) content (0–40%) in ABS. Polycarbonate (PC), styrene-acrylonitrile (SAN) and PB were blended in two steps using a twin screw extruder. Rectangular bars were injection moulded and notched Izod impact tested at

  9. Solvent (acetone-butanol: ab) production

    Science.gov (United States)

    This article describes production of butanol [acetone-butanol-ethanol, (also called AB or ABE or solvent)] by fermentation using both traditional and current technologies. AB production from agricultural commodities, such as corn and molasses, was an important historical fermentation. Unfortunately,...

  10. Rodent Research-1 (RR1) NASA Validation Flight: Mouse liver transcriptomic proteomic and epigenomic data

    Data.gov (United States)

    National Aeronautics and Space Administration — RR-1 is a validation flight to evaluate the hardware operational and science capabilities of the Rodent Research Project on the ISS. RNA DNA and protein were...

  11. Rodent Research-1 (RR1) National Lab Validation Flight: Mouse liver transcriptomic proteomic and epigenomic data

    Data.gov (United States)

    National Aeronautics and Space Administration — The Rodent Reasearch-1 National Lab (RR-1 CASIS) experiment was performed to study the effect of microgravity on muscle wasting. RNA DNA and protein were purified...

  12. Rodent Research-1 (RR1) NASA Validation Flight: Mouse soleus muscle transcriptomic and epigenomic data

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA s Rodent Research (RR) project is playing a critical role in advancing biomedical research on the physiological effects of space environments. Due to the...

  13. Rodent Research-1 (RR1) NASA Validation Flight: Mouse kidney transcriptomic proteomic and epigenomic data

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA s Rodent Research (RR) project is playing a critical role in advancing biomedical research on the physiological effects of space environments. Due to the...

  14. Rodent Research-1 (RR1) NASA Validation Flight: Mouse quadriceps muscle transcriptomic proteomic and epigenomic data

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA s Rodent Research (RR) project is playing a critical role in advancing biomedical research on the physiological effects of space environments. Due to the...

  15. Rodent Research-1 (RR1) NASA Validation Flight: Mouse gastrocnemius muscle transcriptomic proteomic and epigenomic data

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA s Rodent Research (RR) project is playing a critical role in advancing biomedical research on the physiological effects of space environments. Due to the...

  16. Rodent Research-1 (RR1) NASA Validation Flight: Mouse eye transcriptomic and epigenomic data

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA s Rodent Research (RR) project is playing a critical role in advancing biomedical research on the physiological effects of space environments. Due to the...

  17. Rodent Research-1 (RR1) NASA Validation Flight: Mouse adrenal gland transcriptomic proteomic and epigenomic data

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA s Rodent Research (RR) project is playing a critical role in advancing biomedical research on the physiological effects of space environments. Due to the...

  18. FPGA-RR: A Novel FPGA Architecture with RRAM-Based Reconfigurable Interconnects

    OpenAIRE

    Xiao, Bingjun

    2012-01-01

    In this paper we introduce a novel FPGA architecture with RRAM-based reconfiguration (FPGA-RR). This architecture focuses on the redesign of programmable interconnects, the dominant part of FPGA. By renovating the routing structure of FPGA using RRAMs, the architecture achieves significant benefits concerning area, performance and energy consumption. The implementation of FPGA-RR can be realized by the existing CMOS-compatible RRAM fabrication process. A customized CAD flow is provided for FP...

  19. DNA aptamer selection and aptamer-based fluorometric displacement assay for the hepatotoxin microcystin-RR

    International Nuclear Information System (INIS)

    Wu, Shijia; Li, Qi; Duan, Nuo; Wang, Zhouping; Ma, Haile

    2016-01-01

    Microcystin-RR (MC-RR) is a highly acute hepatotoxin produced by cyanobacteria. It is harmful to both humans and the environment. A novel aptamer was identified by the systemic evolution of ligands by exponential enrichment (SELEX) method as a recognition element for determination of MC-RR in aquatic products. The graphene oxide (GO) SELEX strategy was adopted to generate aptamers with high affinity and specificity. Of the 50 aptamer candidates tested, sequence RR-33 was found to display high affinity and selectivity, with a dissociation constant of 45.7 ± 6.8 nM. Aptamer RR-33 therefore was used as the recognition element in a fluorometric assay that proceeds as follows: (1) Biotinylated aptamer RR-33 is immobilized on the streptavidinylated wells of a microtiterplate, and carboxyfluorescein (FAM) labelled complementary DNA is then allowed to hybridize. (2) After removal of excess (unbound) cDNA, sample containing MC-RR is added and incubated at 37 °C for 2 h. (3) Displaced free cDNA is washed away and fluorescence intensity measured at excitation/emission wavelengths of 490/515 nm. The calibration plot is linear in the 0.20 to 2.5 ng·mL −1 concentration range, and the limit of detection is 80 pg·mL −1 . The results indicate that the GO-SELEX technology is appropriate for the screening of aptamers against small-molecule toxins. The detection scheme was applied to the determination of MC-RR in (spiked) water, mussel and fish and gave recoveries between 91 and 98 %. The method compares favorably to a known ELISA. Conceivably, this kind of assay is applicable to other toxins for which appropriate aptamers are available. (author)

  20. Nuevo cultivar de soja de la EEAOC: Yanasu RR New soybean cultivar released by the EEAOC: Yanasu RR

    Directory of Open Access Journals (Sweden)

    José R. Sánchez

    2012-06-01

    Full Text Available Durante las últimas décadas, el cultivo de la soja a nivel mundial tuvo un crecimiento tanto en superficie, como en productividad. En la Argentina sucedió de igual manera, particularmente a comienzos de este siglo, como resultante del uso de alta tecnología, convirtiendo a este cultivo y a sus subproductos en el pilar del sistema granario y exportador. El desarrollo del Noroeste Argentino (NOA coincidió con el proceso a nivel nacional. La Estación Experimental Agroindustrial Obispo Colombres (EEAOC de Tucumán buscó permanentemente producir cultivares adaptados a esta zona, siendo este el principal objetivo del subprograma Mejoramiento Genético del Proyecto Soja. Yanasu es una nueva variedad de soja liberada por la EEAOC, que completa su madurez fisiológica a los 123 días de su siembra (pertenece al grupo de madurez VIII corto y que logra excelentes potenciales de rendimiento. Fue obtenida a través de cruzamiento y posterior avance generacional en la subestación de Monte Redondo (San Agustín, Tucumán. Yanasu RR fue sometida a ensayos comparativos de rendimiento (ECR en cuatro diferentes sitios del área sojera tucumana durante la campañas 2005/2006 y 2006/2007, alcanzando rendimientos superiores a los testigos en la mayoría de los ensayos. Exhibe, entre otras características, baja o nula dehiscencia de vainas y un peso de 1000 semillas de 162,6 gramos. En cuanto a su sanidad, se destaca su tolerancia a las enfermedades cancro del tallo y mancha ojo de rana, así como ante patógenos de semillas como Cercospora kikuchii, Alternaria spp. y Macrophomina spp. Desde 2009/2010 se la incluyó en la Red de Evaluación de Variedades Comerciales del NOA, destacándose por encima del testigo en 12 localidades de la región, con un excelente potencial de rendimiento.In recent decades, soybean planted area, production, and productivity have increased worldwide. This has also occurred in Argentina, especially during the last century, based on

  1. AP calculus AB & BC crash course

    CERN Document Server

    Rosebush, J

    2012-01-01

    AP Calculus AB & BC Crash Course - Gets You a Higher Advanced Placement Score in Less Time Crash Course is perfect for the time-crunched student, the last-minute studier, or anyone who wants a refresher on the subject. AP Calculus AB & BC Crash Course gives you: Targeted, Focused Review - Study Only What You Need to Know Crash Course is based on an in-depth analysis of the AP Calculus AB & BC course description outline and actual AP test questions. It covers only the information tested on the exams, so you can make the most of your valuable study time. Written by experienced math teachers, our

  2. Topological Semimetals Studied by Ab Initio Calculations

    Science.gov (United States)

    Hirayama, Motoaki; Okugawa, Ryo; Murakami, Shuichi

    2018-04-01

    In topological semimetals such as Weyl, Dirac, and nodal-line semimetals, the band gap closes at points or along lines in k space which are not necessarily located at high-symmetry positions in the Brillouin zone. Therefore, it is not straightforward to find these topological semimetals by ab initio calculations because the band structure is usually calculated only along high-symmetry lines. In this paper, we review recent studies on topological semimetals by ab initio calculations. We explain theoretical frameworks which can be used for the search for topological semimetal materials, and some numerical methods used in the ab initio calculations.

  3. STELLAR ARCHEOLOGY IN THE GALACTIC HALO WITH ULTRA-FAINT DWARFS. VII. HERCULES

    Energy Technology Data Exchange (ETDEWEB)

    Musella, Ilaria; Ripepi, Vincenzo; Marconi, Marcella, E-mail: ilaria@na.astro.it, E-mail: ripepi@na.astro.it, E-mail: marcella@na.astro.it [INAF, Osservatorio Astronomico di Capodimonte, I-8013 Napoli (Italy); and others

    2012-09-10

    We present the first time-series study of the ultra-faint dwarf galaxy Hercules. Using a variety of telescope/instrument facilities we secured about 50 V and 80 B epochs. These data allowed us to detect and characterize 10 pulsating variable stars in Hercules. Our final sample includes six fundamental-mode (ab-type) and three first-overtone (c-type) RR Lyrae stars, and one Anomalous Cepheid. The average period of the ab-type RR Lyrae stars, (P{sub ab}) = 0.68 days ({sigma} = 0.03 days), places Hercules in the Oosterhoff II group, as found for almost the totality of the ultra-faint dwarf galaxies investigated so far for variability. The RR Lyrae stars were used to obtain independent estimates of the metallicity, reddening, and distance to Hercules, for which we find [Fe/H] = -2.30 {+-} 0.15 dex, E(B - V) = 0.09 {+-} 0.02 mag, and (m - M){sub 0} = 20.6 {+-} 0.1 mag, in good agreement with the literature values. We have obtained a V, B - V color-magnitude diagram (CMD) of Hercules that reaches V {approx} 25 mag and extends beyond the galaxy's half-light radius over a total area of 40' Multiplication-Sign 36'. The CMD and the RR Lyrae stars indicate the presence of a population as old and metal-poor as (at least) the Galactic globular cluster M68.

  4. Modeling study of the ABS relay valve

    Science.gov (United States)

    Lei, Ming; Lin, Min; Guo, Bin; Luo, Zai; Xu, Weidong

    2011-05-01

    The ABS (anti-lock braking system) relay valve is the key component of anti-lock braking system in most commercial vehicles such as trucks, tractor-trailers, etc. In this paper, structure of ABS relay valve and its work theory were analyzed. Then a mathematical model of ABS relay valve, which was investigated by dividing into electronic part, magnetic part, pneumatic part and mechanical part, was set up. The displacement of spools and the response of pressure increasing, holding, releasing of ABS relay valve were simulated and analyzed under conditions of control pressure 500 KPa, braking pressure 600 KPa, atmospheric pressure 100 KPa and air temperature 310 K. Thisarticle provides reliable theory for improving the performance and efficiency of anti-lock braking system of vehicles.

  5. Ridge Regression and Other Kernels for Genomic Selection with R Package rrBLUP

    Directory of Open Access Journals (Sweden)

    Jeffrey B. Endelman

    2011-11-01

    Full Text Available Many important traits in plant breeding are polygenic and therefore recalcitrant to traditional marker-assisted selection. Genomic selection addresses this complexity by including all markers in the prediction model. A key method for the genomic prediction of breeding values is ridge regression (RR, which is equivalent to best linear unbiased prediction (BLUP when the genetic covariance between lines is proportional to their similarity in genotype space. This additive model can be broadened to include epistatic effects by using other kernels, such as the Gaussian, which represent inner products in a complex feature space. To facilitate the use of RR and nonadditive kernels in plant breeding, a new software package for R called rrBLUP has been developed. At its core is a fast maximum-likelihood algorithm for mixed models with a single variance component besides the residual error, which allows for efficient prediction with unreplicated training data. Use of the rrBLUP software is demonstrated through several examples, including the identification of optimal crosses based on superior progeny value. In cross-validation tests, the prediction accuracy with nonadditive kernels was significantly higher than RR for wheat ( L. grain yield but equivalent for several maize ( L. traits.

  6. Seletividade de diferentes herbicidas à base de glyphosate a soja RR Selectivity of different glyphosate-derived herbicides to soybean RR

    Directory of Open Access Journals (Sweden)

    N. M. Correia

    2007-01-01

    Full Text Available Com o objetivo de avaliar a seletividade de variedades de soja transgênica (CD 214 RR e M-SOY 8008 RR a diferentes herbicidas à base de glyphosate (Roundup Ready, Roundup Transorb, Roundup Original, Roundup WG, Polaris, Gliz, Glifosato Nortox e Trop, foi desenvolvido experimento em condições de campo, no ano agrícola 2005/2006, na Fazenda de Ensino, Pesquisa e Produção da UNESP, campus de Jaboticabal, SP. O delineamento experimental utilizado foi o de blocos ao acaso, num esquema de parcelas subdivididas, com quatro repetições. Os herbicidas foram aplicados na dose de 1,2 kg ha-1 de equivalente ácido de glyphosate, quando as plantas de soja se encontravam com a segunda folha trifoliolada totalmente expandida. Não foram observados sintomas de intoxicação dos herbicidas nas plantas de soja. Quanto às demais características avaliadas, a interação variedade x herbicida não foi significativa, indicando que os fatores comportaram-se de forma independente. Entre as variedades, as plantas de M-SOY 8008 RR apresentaram maior altura e número de nós, porém obtiveram menor produtividade de grãos que as de CD 214 RR, devido ao menor número de grãos por vagem. No tocante aos herbicidas, não houve diferença significativa entre eles, ou seja, eles não influenciaram o desenvolvimento vegetativo e reprodutivo das plantas de soja.A field experiment was conducted at the Education, Research and Production Farm of UNESP in Jaboticabal, SP, Brazil, during the agricultural year 2005/2006 to evaluate the selectivity of the glyphosate-tolerant soybean varieties (CD 214 RR and M-SOY 8008 RR to different glyphosate-derived herbicides (Roundup Ready, Roundup Transorb, Roundup Original, Roundup WG, Polaris, Gliz, Glifosato Nortox, Trop.l. A randomized block in split-plot design was used with four replications. The herbicides had been applied at 1.2 kg ae ha-1, when the soybean plants had reached the second fully expanded leaf stage. No injury due

  7. The Two-Component Signal Transduction System VxrAB Positively Regulates Vibrio cholerae Biofilm Formation.

    Science.gov (United States)

    Teschler, Jennifer K; Cheng, Andrew T; Yildiz, Fitnat H

    2017-09-15

    Two-component signal transduction systems (TCSs), typically composed of a sensor histidine kinase (HK) and a response regulator (RR), are the primary mechanism by which pathogenic bacteria sense and respond to extracellular signals. The pathogenic bacterium Vibrio cholerae is no exception and harbors 52 RR genes. Using in-frame deletion mutants of each RR gene, we performed a systematic analysis of their role in V. cholerae biofilm formation. We determined that 7 RRs impacted the expression of an essential biofilm gene and found that the recently characterized RR, VxrB, regulates the expression of key structural and regulatory biofilm genes in V. cholerae vxrB is part of a 5-gene operon, which contains the cognate HK vxrA and three genes of unknown function. Strains carrying Δ vxrA and Δ vxrB mutations are deficient in biofilm formation, while the Δ vxrC mutation enhances biofilm formation. The overexpression of VxrB led to a decrease in motility. We also observed a small but reproducible effect of the absence of VxrB on the levels of cyclic di-GMP (c-di-GMP). Our work reveals a new function for the Vxr TCS as a regulator of biofilm formation and suggests that this regulation may act through key biofilm regulators and the modulation of cellular c-di-GMP levels. IMPORTANCE Biofilms play an important role in the Vibrio cholerae life cycle, providing protection from environmental stresses and contributing to the transmission of V. cholerae to the human host. V. cholerae can utilize two-component systems (TCS), composed of a histidine kinase (HK) and a response regulator (RR), to regulate biofilm formation in response to external cues. We performed a systematic analysis of V. cholerae RRs and identified a new regulator of biofilm formation, VxrB. We demonstrated that the VxrAB TCS is essential for robust biofilm formation and that this system may regulate biofilm formation via its regulation of key biofilm regulators and cyclic di-GMP levels. This research furthers

  8. Anisotropic Lyra cosmology

    Indian Academy of Sciences (India)

    Einstein geometrized gravitation. Weyl [1] was inspired by it and he was the first to try to unify gravitation and electromagnetism in a single space-time geometry. He showed how one can introduce a vector field in the Riemannian space-time with an intrinsic geometrical significance. But this theory was not accepted as it was ...

  9. Anisotropic Lyra cosmology

    Indian Academy of Sciences (India)

    and the other with variable deceleration parameter have been derived by considering a time-dependent displacement field. ... Sachs cosmological models with a time-dependent displacement field and have made a comparative study of the .... We have four independent equations above, viz. (12), (15), (17) and (20) for five.

  10. Entropy Analysis of RR and QT Interval Variability during Orthostatic and Mental Stress in Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Mathias Baumert

    2014-12-01

    Full Text Available Autonomic activity affects beat-to-beat variability of heart rate and QT interval. The aim of this study was to explore whether entropy measures are suitable to detect changes in neural outflow to the heart elicited by two different stress paradigms. We recorded short-term ECG in 11 normal subjects during an experimental protocol that involved head-up tilt and mental arithmetic stress and computed sample entropy, cross-sample entropy and causal interactions based on conditional entropy from RR and QT interval time series. Head-up tilt resulted in a significant reduction in sample entropy of RR intervals and cross-sample entropy, while mental arithmetic stress resulted in a significant reduction in coupling directed from RR to QT. In conclusion, measures of entropy are suitable to detect changes in neural outflow to the heart and decoupling of repolarisation variability from heart rate variability elicited by orthostatic or mental arithmetic stress.

  11. Degradation of microcystin-RR using boron-doped diamond electrode.

    Science.gov (United States)

    Zhang, Chunyong; Fu, Degang; Gu, Zhongze

    2009-12-30

    Microcystins (MCs), produced by blue-green algae, are one of the most common naturally occurring toxins found in natural environment. The presence of MCs in drinking water sources poses a great threat to people's health. In this study, the degradation behavior of microcystin-RR on boron-doped diamond (BDD) electrode was investigated under galvanostatic conditions. Such parameters as reaction time, supporting electrolyte and applied current density were varied in order to determine their effects on this oxidation process. The experimental results revealed the suitability of electrochemical processes employing BDD electrode for removing MC-RR from the solution. However, the efficient removal of MC-RR only occurred in the presence of sodium chloride that acted as redox mediators and the reaction was mainly affected by the chloride concentration (c(NaCl)) and applied current density (I(appl)). Full and quick removal of 0.50 microg/ml MC-RR in solution was achieved when the operating conditions of c(NaCl) and I(appl) were 20mM and 46.3 mA/cm(2), or 35 mM and 18.2 mA/cm(2) respectively. The kinetics for MC-RR degradation followed a pesudo-first order reaction in most cases, indicating the process was under mass transfer control. As a result of its excellent performance, the BDD technology could be considered as a promising alternative to promote the degradation of MC-RR than chlorination in drinking water supplies.

  12. Adipose tissue (P)RR regulates insulin sensitivity, fat mass and body weight.

    Science.gov (United States)

    Shamansurova, Zulaykho; Tan, Paul; Ahmed, Basma; Pepin, Emilie; Seda, Ondrej; Lavoie, Julie L

    2016-10-01

    We previously demonstrated that the handle-region peptide, a prorenin/renin receptor [(P)RR] blocker, reduces body weight and fat mass and may improve insulin sensitivity in high-fat fed mice. We hypothesized that knocking out the adipose tissue (P)RR gene would prevent weight gain and insulin resistance. An adipose tissue-specific (P)RR knockout (KO) mouse was created by Cre-loxP technology using AP2-Cre recombinase mice. Because the (P)RR gene is located on the X chromosome, hemizygous males were complete KO and had a more pronounced phenotype on a normal diet (ND) diet compared to heterozygous KO females. Therefore, we challenged the female mice with a high-fat diet (HFD) to uncover certain phenotypes. Mice were maintained on either diet for 9 weeks. KO mice had lower body weights compared to wild-types (WT). Only hemizygous male KO mice presented with lower total fat mass, higher total lean mass as well as smaller adipocytes compared to WT mice. Although food intake was similar between genotypes, locomotor activity during the active period was increased in both male and female KO mice. Interestingly, only male KO mice had increased O2 consumption and CO2 production during the entire 24-hour period, suggesting an increased basal metabolic rate. Although glycemia during a glucose tolerance test was similar, KO males as well as HFD-fed females had lower plasma insulin and C-peptide levels compared to WT mice, suggesting improved insulin sensitivity. Remarkably, all KO animals exhibited higher circulating adiponectin levels, suggesting that this phenotype can occur even in the absence of a significant reduction in adipose tissue weight, as observed in females and, thus, may be a specific effect related to the (P)RR. (P)RR may be an important therapeutic target for the treatment of obesity and its associated complications such as type 2 diabetes.

  13. Probabilistic safety analysis for control rod drive system of ET-RR-1

    International Nuclear Information System (INIS)

    Nasr, M.; Nasser, O.

    1988-01-01

    The International Atomic Energy Agency (IAEA) co-ordinated a Research programme on Probabilistic Safety Analysis (PSA) for research reactors; with the participation of several countries. In the framework of this project (Project Int. 9/063) the Egyptian Atomic Energy Authority decided to perform a PSA study on the ET-RR-1 (Egypt Thermal Research Reactor). The study is conducted in collaboration between the nuclear regulatory and safety centre (NRSC) and the reactor department of the nuclear research centre at Inchass. The present work is a part of the PSA study on ET-RR- it is concerning a probabilistic safety analysis of the control rod drive mechanism

  14. Ab initio valence calculations in chemistry

    CERN Document Server

    Cook, D B

    1974-01-01

    Ab Initio Valence Calculations in Chemistry describes the theory and practice of ab initio valence calculations in chemistry and applies the ideas to a specific example, linear BeH2. Topics covered include the Schrödinger equation and the orbital approximation to atomic orbitals; molecular orbital and valence bond methods; practical molecular wave functions; and molecular integrals. Open shell systems, molecular symmetry, and localized descriptions of electronic structure are also discussed. This book is comprised of 13 chapters and begins by introducing the reader to the use of the Schrödinge

  15. MELCOR 1.8.2 assessment: Aerosol experiments ABCOVE AB5, AB6, AB7, and LACE LA2

    Energy Technology Data Exchange (ETDEWEB)

    Souto, F.J.; Haskin, F.E. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering; Kmetyk, L.N. [Sandia National Labs., Albuquerque, NM (United States)

    1994-10-01

    The MELCOR computer code has been used to model four of the large-scale aerosol behavior experiments conducted in the Containment System Test Facility (CSTF) vessel. Tests AB5, AB6 and AB7 of the ABCOVE program simulate the dry aerosol conditions during a hypothetical severe accident in an LMFBR. Test LA2 of the LACE program simulates aerosol behavior in a condensing steam environment during a postulated severe accident in an LWR with failure to isolate the containment. The comparison of code results to experimental data show that MELCOR is able to correctly predict most of the thermal-hydraulic results in the four tests. MELCOR predicts reasonably well the dry aerosol behavior of the ABCOVE tests, but significant disagreements are found in the aerosol behavior modelling for the LA2 experiment. These results tend to support some of the concerns about the MELCOR modelling of steam condensation onto aerosols expressed in previous works. During these analyses, a limitation in the MELCOR input was detected for the specification of the aerosol parameters for more than one component. A Latin Hypercube Sampling (LHS) sensitivity study of the aerosol dynamic constants is presented for test AB6. The study shows the importance of the aerosol shape factors in the aerosol deposition behavior, and reveals that MELCOR input/output processing is highly labor intensive for uncertainty and sensitivity analyses based on LHS.

  16. Diode laser surgery. Ab interno and ab externo versus conventional surgery in rabbits.

    Science.gov (United States)

    Karp, C L; Higginbotham, E J; Edward, D P; Musch, D C

    1993-10-01

    Fibroblastic proliferation of subconjunctival tissues remains a primary mechanism of failure in filtration surgery. Minimizing the surgical manipulation of episcleral tissues may reduce scarring. Laser sclerostomy surgery involves minimal tissue dissection, and is gaining attention as a method of potentially improving filter duration in high-risk cases. Twenty-five New Zealand rabbits underwent filtration surgery in one eye, and the fellow eye remained as the unoperated control. Ten rabbits underwent ab externo diode laser sclerostomy surgery, ten underwent ab interno diode sclerostomy surgery, and five had posterior sclerostomy procedures. Filtration failure was defined as a less-than-4-mmHg intraocular pressure (IOP) difference between the operative and control eyes. The mean time to failure for the ab externo, ab interno, and conventional posterior sclerostomy techniques measured 17.4 +/- 11.5, 13.1 +/- 6.7, and 6.0 +/- 3.1 days, respectively. In a comparison of the laser-treated groups with the conventional procedure, the time to failure was significantly longer (P = 0.02) for the ab externo filter. The mean ab interno sclerostomy duration was longer than the posterior lip procedure, but this difference was not statistically significant (P = 0.15). The overall level of IOP reduction was similar in the three groups. These data suggest that diode laser sclerostomy is a feasible technique in rabbits, and the ab externo approach resulted in longer filter duration than the conventional posterior lip procedure in this model.

  17. Stability of UV exposed RR-P3BT films by spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Diware, Mangesh S.; Byun, J. S.; Hwang, S. Y.; Kim, T. J.; Kim, Y. D.

    2013-01-01

    Stability of regioregular poly(3-butylthiophene) (RR-P3BT) films under irradiation of ultra-violet (UV) light has been studied by spectroscopic ellipsometry at room temperature. Consistent decrease in dielectric function with UV exposure time showed the degree of degradation of polymer. This work suggests that, protective methods are mandatory to use this kind of material in optical devices.

  18. Toxicological Review of Cyanobacterial Toxins: Microcystins Lr, Rr, Yr and La (External Review Draft)

    Science.gov (United States)

    The National Center for Environmental Assessment has prepared the Toxicological Reviews of Cyanobacterial Toxins: Anatoxin-a, Cylindrospermopsin and Microcystins (LR, RR, YR and LA) as a series of dose-response assessments to support the health assessment of unregulated contamina...

  19. Drowsiness discrimination in an overnight driving simulation on the basis of RR and QT intervals

    Directory of Open Access Journals (Sweden)

    Heinze Christian

    2017-09-01

    Full Text Available We examined if ECG-based features are discrimi-native towards drowsiness. Twenty-five volunteers (19–32 years completed 7×40 minutes of monotonous overnight driving simulation, designed to induce drowsiness. ECG (512 s-1 was recorded continuously; subjective ratings of drowsiness on the Karolinska sleepiness scale (KSS were polled every five minutes. ECG recordings were divided into 5-min segments, each associated with the mean of one self- and two observer-KSS ratings. Those mean KSS values were binarized to obtain two classes not drowsy and drowsy. The Q-, R- and T-waves in the recordings were detected; R-peak positions were manually reviewed; the Q- and T-detection method was tested against the manual annotations of Physio-net’s QT database. Power spectral densities of RR intervals (RR-PSD and quantiles of the empirical distribution of heart-rate corrected QTc intervals were estimated. Support-vector machines and random-holdout cross-validation were used for the estimation of the classification error. Using either RR-PSD or QTc features yielded mean test errors of 79.3 ± 0.3 % and 82.7 ± 0.5 %, respectively. Merging RR and QTc features improved the accuracy to 88.3 ± 0.2 %. QTc intervals of the class drowsy were generally prolonged com-pared to not drowsy. Our findings indicate that the inclusion of QT intervals contribute to the discrimination of driver sleepiness.

  20. Measure of the QT-RR Dynamic Coupling in Patients with the Long QT Syndrome

    Czech Academy of Sciences Publication Activity Database

    Halámek, Josef; Couderc, J. P.; Jurák, Pavel; Vondra, Vlastimil; Zareba, W.; Viščor, Ivo; Leinveber, P.

    2012-01-01

    Roč. 17, č. 4 (2012), s. 323-330 ISSN 1082-720X R&D Projects: GA MŠk ME09050 Institutional support: RVO:68081731 Keywords : Long QT syndrome * Dynamic QT-RR coupling * Holter recording * QT adaptation * QT parameters Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 1.084, year: 2012

  1. Work space optimization of a r-r planar manipulator using particle ...

    African Journals Online (AJOL)

    Work space optimization of a r-r planar manipulator using particle swarm optimization technique. G. Chaitanya. 1*. , B. Muddu Krishna. 2. 1*Department of Mechanical Engineering, R.V.R &J.C College of Engineering, Guntur-19 (A.P), INDIA. 2 Department of Mechanical Engineering, R.V.R &J.C College of Engineering, ...

  2. Statistical modelling of the differences between successive R-R intervals.

    Science.gov (United States)

    Mandrekar, Sumithra J; Nagaraja, Haikady N; Berntson, Gary G

    2005-02-15

    Understanding the behaviour of R-R interval data and its successive differences is critical to the dynamics of cardiac control. Several time domain measures that quantify R-R interval variability have important clinical significance in terms of risk stratification and evaluating the effectiveness of treatment procedures. The present approach at examining the distributions of successive beat-to-beat differences of R-R interval data from different populations and under different conditions (baseline and reaction times) provides a valuable insight into their previously unexplored distributional properties. In particular, our analysis reveals that the successive differences have non-normal statistical distributions (a contradiction to the commonly used assumption of normality), and the absolute successive R-R interval differences approximately follows a Weibull distribution. As an illustration of the utility of this approach, we explore the statistical properties of the time domain measure: root mean square successive difference, study the association between the Weibull scale parameter estimate and respiratory sinus arrhythmia, and propose improvements in artifact detection algorithms. Copyright 2004 John Wiley & Sons, Ltd.

  3. Influence of Age and Aerobic Fitness on the Multifractal Characteristics of Electrocardiographic RR Time-Series

    Directory of Open Access Journals (Sweden)

    Michael James Lewis

    2013-05-01

    Full Text Available Multifractal properties of electrocardiographic inter-beat (RR time-series offer insight into its long-term correlation structure, independently of RR variability. Here we quantify multifractal characteristics of RR data during 24-hour diurnal-nocturnal activity in healthy participants. We tested the hypotheses that (1 age, gender and aerobic fitness influence RR multifractal properties, and that (2 these are influenced by circadian variation.Seventy adults (39 males aged 19-58 years and of various fitness levels were monitored using 24-hour ECG. Participants were dichotomised by median age and fitness for sub-group analysis. Gender and fitness were independent of age (p=0.1, p>0.5. Younger/older group ages were substantially different (p<0.0005 and were independent of gender and fitness. Multifractality was quantified using the probability spectrum of Hölder exponents (h, from which modal h (h* and the full-width and half-widths at half-maximum measures (FWHM, HWHM+ and HWHM- were derived. FWHM decreased (p=0.004 and h* increased (p=0.011 in older people, indicating diminished long-range RR correlations and weaker anti-persistent behavior. Anti-persistent correlation (h* was strongest in the youngest/fittest individuals and weakest in the oldest/least fit individuals (p=0.015. Long-range correlation (HWHM+/FWHM was strongest in the fittest males and weakest in the least fit females (p=0.007-0.033.Multifractal RR characteristics in our healthy participants showed strong age-dependence with diminished long-range anti-persistent correlation in older people. Circadian variation of these characteristics was influenced by fitness and gender: fitter males and females of all ages had the greatest degree of multifractality or long-range order. Multifractal characterisation appears to be a useful method for exploring the physiological basis of long-term correlation structure in RR time-series as well as the benefits thereon of physical fitness training.

  4. Ab Initio molecular dynamics with excited electrons

    NARCIS (Netherlands)

    Alavi, A.; Kohanoff, J.; Parrinello, M.; Frenkel, D.

    1994-01-01

    A method to do ab initio molecular dynamics suitable for metallic and electronically hot systems is described. It is based on a density functional which is costationary with the finite-temperature functional of Mermin, with state being included with possibly fractional occupation numbers.

  5. Relationship between electrocardiographic RR and QT interval variabilities and indices of ventricular function in healthy subjects

    International Nuclear Information System (INIS)

    Lewis, M J; Short, A L

    2008-01-01

    To date there has been no simultaneous characterization of the influence of physical exercise on cardiac ventricular function and cardiac electrical variability. Consequently, little is known about the relationship between the ventricular function and either heart rate (RR) or repolarization (QT) variability. In particular, the relationship between the QT variability index (QTVI) and ventricular function would be of clinical interest. Eight males of similar age (20.7 ± 0.4 years (mean ± SD)), mass (78.4 ± 7.7 kg) and aerobic fitness (50.7 ± 4.9 ml kg −1 min −1 ) undertook progressive bicycle exercise. A three-lead Holter ECG was recorded continuously during pre-exercise, exercise and recovery, and mean values of RR and QT, their variabilities (RMSSD and SDNN) and their relative variability (QTVI) were determined. Traditional indices of ventricular function were determined beat to beat via impedance cardiography, and beat-to-beat blood pressure was recorded via photoplethysmography. Multiple linear regression analysis using the stepwise method resulted in significant models for each of the dependent variables (RR, QT, RR and QT variabilities, QTVI), using indices of the ventricular function as predictor variables. Notably, the QTVI reflected both the stroke volume index (SVI) and the acceleration index (ACI), which are measures of cardiac 'output' per contraction and the force of contraction, respectively. This relationship was largely unperturbed by physical exercise, in contrast with the results for all other dependent variables. We conclude that the QTVI is a reasonably consistent measure of the cardiac ventricular function, and as such is a more useful index than other parameters based on RR or QT interval alone

  6. The role of echolocation in the hunting of terrestrial prey--new evidence for an underestimated strategy in the gleaning bat, Megaderma lyra.

    Science.gov (United States)

    Schmidt, S; Hanke, S; Pillat, J

    2000-10-01

    The observation that gleaning bats detect prey by its noises, together with difficulties in recording their faint sonar calls, have led some authors to conclude that gleaning bats may not use echolocation in certain hunting situations. In particular, it is conjectured that echolocation plays no role in the classification and tracking of prey. In the present study, we show that the gleaning bat, Megaderma lyra, is able to find silent and motionless prey on the ground. The significance of sonar for catching a variety of terrestrial prey is established in a standardized situation. Sonar calls were found to be emitted during all stages, i.e. approach, hovering above the prey, and return to the roost, of every hunting flight. The harmonic pattern of the calls differed significantly between these stages, calls with three or more prominent components prevailing during hovering. Bats identified prey and rejected dummies while hovering above them. During this stage, increased call rates and reduced call durations were found. Echolocation activity during, and the duration of, the hovering phase depended on prey type, in particular on prey movement. The prey-dependent shifts in sonar activity, the broadband call structure with an emphasis on higher harmonics, and a systematic shift of the calls' peak frequencies during hovering, are discussed as adaptations to identifying prey by sonar.

  7. Annotation and analysis of a large cuticular protein family with the R&R Consensus in Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    He Ningjia

    2008-01-01

    Full Text Available Abstract Background The most abundant family of insect cuticular proteins, the CPR family, is recognized by the R&R Consensus, a domain of about 64 amino acids that binds to chitin and is present throughout arthropods. Several species have now been shown to have more than 100 CPR genes, inviting speculation as to the functional importance of this large number and diversity. Results We have identified 156 genes in Anopheles gambiae that code for putative cuticular proteins in this CPR family, over 1% of the total number of predicted genes in this species. Annotation was verified using several criteria including identification of TATA boxes, INRs, and DPEs plus support from proteomic and gene expression analyses. Two previously recognized CPR classes, RR-1 and RR-2, form separate, well-supported clades with the exception of a small set of genes with long branches whose relationships are poorly resolved. Several of these outliers have clear orthologs in other species. Although both clades are under purifying selection, the RR-1 variant of the R&R Consensus is evolving at twice the rate of the RR-2 variant and is structurally more labile. In contrast, the regions flanking the R&R Consensus have diversified in amino-acid composition to a much greater extent in RR-2 genes compared with RR-1 genes. Many genes are found in compact tandem arrays that may include similar or dissimilar genes but always include just one of the two classes. Tandem arrays of RR-2 genes frequently contain subsets of genes coding for highly similar proteins (sequence clusters. Properties of the proteins indicated that each cluster may serve a distinct function in the cuticle. Conclusion The complete annotation of this large gene family provides insight on the mechanisms of gene family evolution and clues about the need for so many CPR genes. These data also should assist annotation of other Anopheles genes.

  8. Towards hydrogen metallization: an Ab initio approach

    International Nuclear Information System (INIS)

    Bernard, St.

    1998-01-01

    The quest for metallic hydrogen is a major goal for both theoretical and experimental condensed matter physics. Hydrogen and deuterium have been compressed up to 200 GPa in diamond anvil cells, without any clear evidence for a metallic behaviour. Loubeyere has recently suggested that hydrogen could metallize, at pressures within experimental range, in a new Van der Waals compound: Ar(H 2 ) 2 which is characterized at ambient pressure by an open and anisotropic sublattice of hydrogen molecules, stabilized by an argon skeleton. This thesis deals with a detailed ab initio investigation, by Car-Parrinello molecular dynamics methods, of the evolution under pressure of this compound. In a last chapter, we go to much higher pressures and temperatures, in order to compare orbital and orbital free ab initio methods for the dense hydrogen plasma. (author)

  9. Holocene paleoclimatic and paleohydrological changesin the Sárrét basin, NW Hungary

    Directory of Open Access Journals (Sweden)

    Pál Sümegi

    2008-12-01

    Full Text Available According to detailed sedimentological and paleontological analyses carried out on samples taken from the Sárrét–Nádasdladány core-profile, a complete environmental history of a neotectonic depression was drawn. The sequence is composed of fluvial-lacustrine and marshland deposits which started to accumulate during the Late Glacial and culminated at the beginning of the Holocene. The highly characteristic changes in the biofacies were linked to changes in the lithofacies within this sequence. A transition in the dominance of moving water species, observable initially in lacustrine species preferring well-lit, well-oxygenated conditions was observed. Eventually, the littoral and eutrophic lacustrine species, as well as marsh-dwellers, became dominant in the profile, marking the emergence of uniform peat land in the Sárrét Basin.

  10. New approach for visualization of relationships between RR and JT intervals.

    Directory of Open Access Journals (Sweden)

    Pranas Ziaukas

    Full Text Available This paper presents the concept of perfect matrices of Lagrange differences which are used to analyze relationships between RR and JT intervals during the bicycle ergometry exercise. The concept of the perfect matrix of Lagrange differences, its parameters, the construction of the load function and the corresponding optimization problem, the introduction of internal and external smoothing, embedding of the scalar parameter time series into the phase plane-all these computational techniques allow visualization of complex dynamical processes taking place in the cardiovascular system during the load and the recovery processes. Detailed analysis is performed with one person's RR and JT records only-but the presented techniques open new possibilities for novel interpretation of the dynamics of the cardiovascular system.

  11. POL ABS calibrations 2005-2007

    OpenAIRE

    Moate, B. D.; Thorne, P. D.; Cooke, R. D.; Betteridge, K. F. E.

    2007-01-01

    Suspended inorganic particles (such as sands) strongly scatter incident acoustic pressure waves at MHz frequencies, with the amplitude of the backscattered pressure being related to the mass concentration and nominal size of the particles in suspension. Over the past two decades, this physical premise has led to the development of transducer based Acoustic Backscatter Systems (ABS), usually designed to collect profile measurements at centimetric resolution over a metre or so of the near-bed r...

  12. Ab initio vel ex eventu. II

    Science.gov (United States)

    Thiessen, P. A.; Treder, H.-J.

    Jedes initium wird durch experimenta crucis zum eventus. Jedes theoretisch interpretierbare ex-eventu-Resultat führt auf ein neues Initium. Gerade dies ist die gemeinsame Aussage von Atomistik, Quantenmechanik und Relativitätstheorie.Translated AbstractAb initio vel ex eventu. IIEvery initium becomes an eventus by experimenta crucis. Every theoretically interpretable ex-eventu result leads to a new initium. Right this is the joint assertion of atomism, quantum mechanics, and relativity.

  13. Germacrene D Cyclization: An Ab Initio Investigation

    OpenAIRE

    Setzer, William N.

    2008-01-01

    Essential oils that contain large concentrations of germacrene D are typically accompanied by cadinane sesquiterpenoids. The acid-catalyzed cyclization of germacrene D to give cadinane and selinane sesquiterpenes has been computationally investigated using both density functional (B3LYP/6-31G*) and post Hartree-Fock (MP2/6-31G* *) ab initio methods. The calculated energies are in general agreement with experimentally observed product distributions, both from acid-catalyzed cyclizations as wel...

  14. Matrix string models for exact (2,2) string theories in RR backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Bonelli, Giulio E-mail: gbonelli@ulb.ac.be

    2003-01-20

    We formulate matrix string models on a class of exact string backgrounds with non-constant RR-flux parameterized by a holomorphic prepotential function and with manifest (2,2) supersymmetry. This lifts these string theories to M-theory exposing the non-perturbative string interaction which is studied by generalizing the instanton asymptotic expansion, well established in the flat background case, to this more general case. We obtain also a companion matrix model with four manifest supersymmetries in eleven dimensions.

  15. Research performed at the ET-RR-1 reactor using the neutron scattering equipment

    International Nuclear Information System (INIS)

    Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.

    1990-02-01

    This report represents the results of studies and measurements, performed at the ET-RR-1 reactor, using the neutron scattering equipment supplied by the IAEA according to the technical assistance project EGY/1/11/10. The results of these studies, starting in 1980 and continuing to date, are discussed; the use of the equipment, both as a neutron monochromator and fixed scattering angle spectrometer, is also assessed. (author). 19 refs, 17 figs

  16. Ab interno trabeculectomy: patient selection and perspectives

    Science.gov (United States)

    Vinod, Kateki; Gedde, Steven J

    2016-01-01

    Ab interno trabeculectomy is one among several recently introduced minimally invasive glaucoma surgeries that avoid a conjunctival incision and full-thickness sclerostomy involved in traditional glaucoma surgery. Ablation of the trabecular meshwork and inner wall of Schlemm’s canal is performed in an arcuate fashion via a clear corneal incision, alone or in combination with phacoemulsification cataract surgery. Intraocular pressure reduction following ab interno trabeculectomy is limited by resistance in distal outflow pathways and generally stabilizes in the mid-to-high teens. Relief of medication burden has been demonstrated by some studies. A very low rate of complications, most commonly transient hyphema and intraocular pressure elevations in the immediate postoperative period, have been reported. However, available data are derived from small retrospective and prospective case series. Randomized, controlled trials are needed to better elucidate the potential merits of ab interno trabeculectomy in the combined setting versus phacoemulsification cataract surgery alone and to compare it with other minimally invasive glaucoma surgeries. PMID:27574396

  17. Highly scalable Ab initio genomic motif identification

    KAUST Repository

    Marchand, Benoit

    2011-01-01

    We present results of scaling an ab initio motif family identification system, Dragon Motif Finder (DMF), to 65,536 processor cores of IBM Blue Gene/P. DMF seeks groups of mutually similar polynucleotide patterns within a set of genomic sequences and builds various motif families from them. Such information is of relevance to many problems in life sciences. Prior attempts to scale such ab initio motif-finding algorithms achieved limited success. We solve the scalability issues using a combination of mixed-mode MPI-OpenMP parallel programming, master-slave work assignment, multi-level workload distribution, multi-level MPI collectives, and serial optimizations. While the scalability of our algorithm was excellent (94% parallel efficiency on 65,536 cores relative to 256 cores on a modest-size problem), the final speedup with respect to the original serial code exceeded 250,000 when serial optimizations are included. This enabled us to carry out many large-scale ab initio motiffinding simulations in a few hours while the original serial code would have needed decades of execution time. Copyright 2011 ACM.

  18. Studies for the radiation levels and shielding in RR73, RR77 and UJ76 in IR7 for collimation phase 1 - 035

    CERN Document Server

    Tsoulou, A; Ferrari, A; CERN. Geneva. AB Department

    2005-01-01

    The Collimation project is one of the most crucial for the LHC performance. 54 movable, two-sided collimators will be placed in two insertions, i.e. IR3 and IR7, which will be among the most radioactive in the LHC. For a normal machine operation, it is essential that the electronics do not degrade or fail â€" at least very often â€" due to irradiation. The radiation levels initially estimated in IR7 (RR73/77 and UJ76) were too high for the electronics to tolerate. A shielding study was necessary to be done, in parallel with the study for the absorber positions. This article summarizes the shielding proposed and the radiation levels calculated for the final collimator and absorber positions as indicated by the FLUKA team.

  19. Studies for the radiation levels and shielding in RR73, RR77 and UJ76 in IR7 for collimation phase 1 - 372

    CERN Document Server

    Tsoulou, A; Ferrari, A

    2005-01-01

    The Collimation project is one of the most crucial for the LHC performance. 54 movable, two-sided collimators will be placed in two insertions, i.e. IR3 and IR7, which will be among the most radioactive in the LHC. For a normal machine operation, it is essential that the electronics do not degrade or fail â€" at least very often â€" due to irradiation. The radiation levels initially estimated in IR7 (RR73/77 and UJ76) were too high for the electronics to tolerate. A shielding study was necessary to be done, in parallel with the study for the absorber positions. This article summarizes the shielding proposed and the radiation levels calculated for the final collimator and absorber positions as indicated by the FLUKA team.

  20. Mantle cell lymphoma-like lymphomas in c-myc-3'RR/p53+/- mice and c-myc-3'RR/Cdk4R24C mice: differential oncogenic mechanisms but similar cellular origin.

    Science.gov (United States)

    Rouaud, Pauline; Fiancette, Rémi; Vincent-Fabert, Christelle; Magnone, Virginie; Cogné, Michel; Dubus, Pierre; Denizot, Yves

    2012-05-01

    Mantle cell lymphoma (MCL) is a malignant lymphoproliferative B-cell disorder that does not occur spontaneously in mice but experimental mice model have been developed. Recently two different mice models prone to develop MCL-like lymphomas were generated: c-myc-3'RR/Cdk4(R24C) mice and c-myc-3'RR/p53+/- mice. Comparison of their gene expression profiles does not highlight specific differences other than those in relation with their specific mutational status (i.e., Cdk4(R24C) mutation or p53 mutations). We propose that similarly to typical human MCL and its blastoid or cyclin-D1 variants that correspond to the same genetic entity, MCL-like lymphomas of c-myc-3'RR/ p53+/- mice and c-myc-3'RR/Cdk4(R24C) mice represent a spectrum of the same entity.

  1. Undoing Gender Through Legislation and Schooling: the Case of AB 537 and AB 394 IN California, USA

    Science.gov (United States)

    Knotts, Greg

    2009-11-01

    This article investigates California laws AB 537: The Student Safety and Violence Prevention Act of 2000, and the recently enacted AB 394: Safe Place to Learn Act. Both demand that gender identity and sexual orientation be added to the lexicon of anti-harassment protection in public education. However, despite these progressive measures, schools have an unconscious acceptance of heteronormativity and gendered norms, which undermines both the spirit and language of these laws. This paper examines how California schools can both change standard practices and realise the transformative social change that laws like AB 537 and AB 394 can instigate. I assert that the systemic implementation of these laws, through the adoption, enforcement and evaluation of existing AB 537 Task Force Recommendations, is necessary for their success. My second assertion is that AB 537 and AB 394 have the potential to change and reconstitute gender-based and heteronormative standards at school sites.

  2. Germacrene D cyclization: an Ab initio investigation.

    Science.gov (United States)

    Setzer, William N

    2008-01-01

    Essential oils that contain large concentrations of germacrene D are typically accompanied by cadinane sesquiterpenoids. The acid-catalyzed cyclization of germacrene D to give cadinane and selinane sesquiterpenes has been computationally investigated using both density functional (B3LYP/6-31G(*)) and post Hartree-Fock (MP2/6-31G(* *)) ab initio methods. The calculated energies are in general agreement with experimentally observed product distributions, both from acid-catalyzed cyclizations as well as distribution of the compounds in essential oils.

  3. Germacrene D Cyclization: An Ab Initio Investigation

    Directory of Open Access Journals (Sweden)

    William N. Setzer

    2008-01-01

    Full Text Available Essential oils that contain large concentrations of germacrene D are typically accompanied by cadinane sesquiterpenoids. The acid-catalyzed cyclization of germacrene D to give cadinane and selinane sesquiterpenes has been computationally investigated using both density functional (B3LYP/6-31G* and post Hartree-Fock (MP2/6-31G** ab initio methods. The calculated energies are in general agreement with experimentally observed product distributions, both from acid-catalyzed cyclizations as well as distribution of the compounds in essential oils.

  4. Rodent Research-1 (RR1) NASA Validation Flight: Mouse extensor digitorum longus muscle transcriptomic and epigenomic data

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA s Rodent Research (RR) project is playing a critical role in advancing biomedical research on the physiological effects of space environments. Due to the...

  5. Rodent Research-1 (RR1) NASA Validation Flight: Mouse tibialis anterior muscle transcriptomic proteomic and epigenomic data

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA s Rodent Research (RR) project is playing a critical role in advancing biomedical research on the physiological effects of space environments. Due to the...

  6. Raaka-ainevaraston layout-suunnittelu ja kehittäminen : kohde: RR-Sorvaus Oy

    OpenAIRE

    Fagerström, Toni

    2010-01-01

    Opinnäytetyön ensimmäisenä tavoitteena oli salolaisen RR-Sorvaus Oy:n varastointijärjestelmän kehittäminen. Työ aloitettiin varaston perustamisesta, koska yrityksellä ei ollut käytössään minkäänlaista varastojärjestelmää raaka-aineille. Toisena tavoitteena oli varastoon sitoutuneen pääoman pienentäminen ja siirtyminen tilausohjattuun toimintatapaan. Kolmantena tavoitteena oli löytää sopiva layout-ratkaisu varastoitaville raaka-aineille, sahalle ja yritykseen hankittavalle seinäkääntönosturill...

  7. Multipurpose RTOF Fourier diffractometer at the ET-RR-1 reactor

    International Nuclear Information System (INIS)

    Maayouf, R.M.A.; Tiitta, A.T.

    1993-09-01

    The present work represents a further study of the basic RTOF Fourier multipurpose diffractometer, to start with, at the ET-RR-1 reactor. The functions of the suggested arrangement are thoroughly discussed and the possibilities if its expansion are also assessed. The flexibility of the arrangement allows its further expansion both for stress measurement at 90 deg. scattering angle with two detector banks at opposite sides of the incident beam and for operation in the transmission diffraction mode. (orig.). (19 refs., 10 figs., 1 tab.)

  8. Detailed evaluation of ET-RR-2 neutronic design: approach to criticality

    International Nuclear Information System (INIS)

    Ashoub, N.; Amin, E.

    2000-01-01

    The ET-RR-2 safety analysis evaluation effort included the assessment of the reactor core nuclear design parameters. The present work complements the previous effort of neutronic calculations using NCNSRC computer code packages. This paper is the first in comprehensive neutronic calculation assessment up to the equilibrium core. It deals with evaluation of neutronic calculation submitted during the early phase of the licensing process; namely the proposal to assemble the first critical core, calculation of power peaking factor and determination of detailed energy group flux distribution in the core particularly in the cobalt irradiation position. The neutronic design criteria are examined qualitatively and quantitatively in the present paper

  9. Using Complexity Metrics With R-R Intervals and BPM Heart Rate Measures

    DEFF Research Database (Denmark)

    Wallot, Sebastian; Fusaroli, Riccardo; Tylén, Kristian

    2013-01-01

    of interpersonal coordination. However, there is no consensus about which measurements and analytical tools are most appropriate in mapping the temporal dynamics of heart rate and quite different metrics are reported in the literature. As complexity metrics of heart rate variability depend critically...... dynamics, but their power to do so critically depends on the type data that is employed: While R-R intervals are very susceptible to nonlinear analyses, the success of nonlinear methods for BPM data critically depends on their construction. Generally, ‘oversampled’ BPM time-series can be recommended...

  10. Quantum phases of AB2 fermionic chains

    International Nuclear Information System (INIS)

    Murcia-Correa, L S; Franco, R; Silva-Valencia, J

    2016-01-01

    A fermionic chain is a one-dimensional system with fermions that interact locally and can jump between sites in the lattice, in particular an AB n chain type, where A and B are sites that exhibit a difference in energy level of Δ and site B is repeated n-times, such that the unit cell has n +1 sites. A limit case of this model, called the ionic Hubbard model (n = 1), has been widely studied due to its interesting physics and applications. In this paper, we study the ground state of an AB 2 chain, which describes the material R 4 [Pt 2 (P 2 O 5 H 2 ) 4 X] · nH 2 O. Specifically, we consider a filling with two electrons per unit cell, and using the density matrix renormalization group method we found that the system exhibits the band insulator and Mott correlated insulator phases, as well as an intermediate phase between them. For couplings of Δ = 2,10 and 20, we estimate the critical points that separate these phases through the structure factor and the energy gap in the sector of charge and spin, finding that the position of the critical point rises as a function of Δ. (paper)

  11. Popular Herbig AE star AB Aur

    International Nuclear Information System (INIS)

    Shevchenko, V.S.

    1987-01-01

    The variability of AB Aur emission line H α , H β , H γ profiles, equivalent widths (EW λ ) and relative intensity have been observed on the photoelectric scanner. During the 20 d observation period EW λ H α ranged from 23.20 to 35.35 A. Mean EW λ H α is 27.25 A, daily average deviation is 3.60 ± 0.07 A. The minimum time of variability is 1 h . The chromospheric lines near-infrared triplet Ca II and KCaII and emission lines H β -H13, P12-P20, 0I 8446.5 A and the variability of other lines have been studied on the photographic and image-tube spectra. The intensity of these lines and EW λ changed 2-4 times during an interval from 1 h to several years. The AB Aur variability nature of emission lines made it possible to assume that the ''deep chromosphere'' is not a centre-symmetrical or axisymmetrical formation but is a conglomerate of different density and speed gas condensations

  12. Longitudinal wheel slip during ABS braking

    Science.gov (United States)

    Hartikainen, Lassi; Petry, Frank; Westermann, Stephan

    2015-02-01

    Anti-lock braking system (ABS) braking tests with two subcompact passenger cars were performed on dry and wet asphalt, as well as on snow and ice surfaces. The operating conditions of the tyres in terms of wheel slip were evaluated using histograms of the wheel slip data. The results showed different average slip levels for different road surfaces. It was also found that changes in the tyre tread stiffness affected the slip operating range through a modification of the slip value at which the maximum longitudinal force is achieved. Variation of the tyre footprint length through modifications in the inflation pressure affected the slip operating range as well. Differences in the slip distribution between vehicles with different brake controllers were also observed. The changes in slip operating range in turn modified the relative local sliding speeds between the tyre and the road. The results highlight the importance of the ABS controller's ability to adapt to changing slip-force characteristics of tyres and provide estimates of the magnitude of the effects of different tyre and road operating conditions.

  13. Biosorption of Acid Blue 290 (AB 290) and Acid Blue 324 (AB 324) dyes on Spirogyra rhizopus

    International Nuclear Information System (INIS)

    Ozer, Ayla; Akkaya, Goenuel; Turabik, Meral

    2006-01-01

    In this study, the biosorption of Acid Blue 290 and Acid Blue 324 on Spirogyra rhizopus, a green algae growing on fresh water, was studied with respect to initial pH, temperature, initial dye concentration and biosorbent concentration. The optimum initial pH and temperature values for AB 290 and AB 324 biosorption were found to be 2.0, 30 deg. C and 3.0, 25 deg. C, respectively. It was observed that the adsorbed AB 290 and AB 324 amounts increased with increasing the initial dye concentration up to 1500 and 750 mg/L, respectively. The Langmuir, Freundlich, Redlich-Peterson and Koble-Corrigan isotherm models were applied to the experimental equilibrium data and the isotherm constants were determined by using Polymath 4.1 software. The monolayer coverage capacities of S. rhizopus for AB 290 and AB 324 dyes were found as 1356.6 mg/g and 367.0 mg/g, respectively. The intraparticle diffusion model and the pseudo-second order kinetic model were applied to the experimental data in order to describe the removal mechanism of these acidic dyes by S. rhizopus. The pseudo-second order kinetic model described very well the biosorption kinetics of AB 290 and AB 324 dyes. Thermodynamic studies showed that the biosorption of AB 290 and AB 324 on S. rhizopus was exothermic in nature

  14. Biosorption of Acid Blue 290 (AB 290) and Acid Blue 324 (AB 324) dyes on Spirogyra rhizopus

    Energy Technology Data Exchange (ETDEWEB)

    Ozer, Ayla [University of Mersin, Department of Chemical Engineering, 33343 Ciftlikkoey-Mersin (Turkey)]. E-mail: ayozer@mersin.edu.tr; Akkaya, Goenuel [University of Mersin, Department of Chemical Engineering, 33343 Ciftlikkoey-Mersin (Turkey); Turabik, Meral [University of Mersin, Higher Vocational School of Mersin, Chemical Prog., Ciftlikkoey-Mersin (Turkey)

    2006-07-31

    In this study, the biosorption of Acid Blue 290 and Acid Blue 324 on Spirogyra rhizopus, a green algae growing on fresh water, was studied with respect to initial pH, temperature, initial dye concentration and biosorbent concentration. The optimum initial pH and temperature values for AB 290 and AB 324 biosorption were found to be 2.0, 30 deg. C and 3.0, 25 deg. C, respectively. It was observed that the adsorbed AB 290 and AB 324 amounts increased with increasing the initial dye concentration up to 1500 and 750 mg/L, respectively. The Langmuir, Freundlich, Redlich-Peterson and Koble-Corrigan isotherm models were applied to the experimental equilibrium data and the isotherm constants were determined by using Polymath 4.1 software. The monolayer coverage capacities of S. rhizopus for AB 290 and AB 324 dyes were found as 1356.6 mg/g and 367.0 mg/g, respectively. The intraparticle diffusion model and the pseudo-second order kinetic model were applied to the experimental data in order to describe the removal mechanism of these acidic dyes by S. rhizopus. The pseudo-second order kinetic model described very well the biosorption kinetics of AB 290 and AB 324 dyes. Thermodynamic studies showed that the biosorption of AB 290 and AB 324 on S. rhizopus was exothermic in nature.

  15. Biosorption of Acid Blue 290 (AB 290) and Acid Blue 324 (AB 324) dyes on Spirogyra rhizopus.

    Science.gov (United States)

    Ozer, Ayla; Akkaya, Gönül; Turabik, Meral

    2006-07-31

    In this study, the biosorption of Acid Blue 290 and Acid Blue 324 on Spirogyra rhizopus, a green algae growing on fresh water, was studied with respect to initial pH, temperature, initial dye concentration and biosorbent concentration. The optimum initial pH and temperature values for AB 290 and AB 324 biosorption were found to be 2.0, 30 degrees C and 3.0, 25 degrees C, respectively. It was observed that the adsorbed AB 290 and AB 324 amounts increased with increasing the initial dye concentration up to 1500 and 750 mg/L, respectively. The Langmuir, Freundlich, Redlich-Peterson and Koble-Corrigan isotherm models were applied to the experimental equilibrium data and the isotherm constants were determined by using Polymath 4.1 software. The monolayer coverage capacities of S. rhizopus for AB 290 and AB 324 dyes were found as 1356.6 mg/g and 367.0 mg/g, respectively. The intraparticle diffusion model and the pseudo-second order kinetic model were applied to the experimental data in order to describe the removal mechanism of these acidic dyes by S. rhizopus. The pseudo-second order kinetic model described very well the biosorption kinetics of AB 290 and AB 324 dyes. Thermodynamic studies showed that the biosorption of AB 290 and AB 324 on S. rhizopus was exothermic in nature.

  16. Workshop on automated beam steering and shaping (ABS). Proceedings

    International Nuclear Information System (INIS)

    Lindroos, M.

    1999-01-01

    A workshop on Automated Beam Steering and Shaping (ABS) was held at CERN in December 1998. This was the first workshop dedicated to this subject. The workshop had two major goals: to review the present status of ABS algorithms and systems around the world and to create a worldwide ABS community. These proceedings contain summary reports from all sessions, contributions from several presentations held at the workshop, and a complete set of abstracts for all presentations. (orig.)

  17. Bacillus thuringiensis Cry34Ab1/Cry35Ab1 interactions with western corn rootworm midgut membrane binding sites.

    Directory of Open Access Journals (Sweden)

    Huarong Li

    Full Text Available BACKGROUND: Bacillus thuringiensis (Bt Cry34Ab1/Cry35Ab1 are binary insecticidal proteins that are co-expressed in transgenic corn hybrids for control of western corn rootworm, Diabrotica virgifera virgifera LeConte. Bt crystal (Cry proteins with limited potential for field-relevant cross-resistance are used in combination, along with non-transgenic corn refuges, as a strategy to delay development of resistant rootworm populations. Differences in insect midgut membrane binding site interactions are one line of evidence that Bt protein mechanisms of action differ and that the probability of receptor-mediated cross-resistance is low. METHODOLOGY/PRINCIPAL FINDINGS: Binding site interactions were investigated between Cry34Ab1/Cry35Ab1 and coleopteran active insecticidal proteins Cry3Aa, Cry6Aa, and Cry8Ba on western corn rootworm midgut brush border membrane vesicles (BBMV. Competitive binding of radio-labeled proteins to western corn rootworm BBMV was used as a measure of shared binding sites. Our work shows that (125I-Cry35Ab1 binds to rootworm BBMV, Cry34Ab1 enhances (125I-Cry35Ab1 specific binding, and that (125I-Cry35Ab1 with or without unlabeled Cry34Ab1 does not share binding sites with Cry3Aa, Cry6Aa, or Cry8Ba. Two primary lines of evidence presented here support the lack of shared binding sites between Cry34Ab1/Cry35Ab1 and the aforementioned proteins: 1 No competitive binding to rootworm BBMV was observed for competitor proteins when used in excess with (125I-Cry35Ab1 alone or combined with unlabeled Cry34Ab1, and 2 No competitive binding to rootworm BBMV was observed for unlabeled Cry34Ab1 and Cry35Ab1, or a combination of the two, when used in excess with (125I-Cry3Aa, or (125I-Cry8Ba. CONCLUSIONS/SIGNIFICANCE: Combining two or more insecticidal proteins active against the same target pest is one tactic to delay the onset of resistance to either protein. We conclude that Cry34Ab1/Cry35Ab1 are compatible with Cry3Aa, Cry6Aa, or Cry8Ba

  18. Qualification of NISTmAb charge heterogeneity control assays.

    Science.gov (United States)

    Turner, Abigail; Schiel, John E

    2018-03-01

    The NISTmAb is a monoclonal antibody Reference Material from the National Institute of Standards and Technology; it is a class-representative IgG1κ intended serve as a pre-competitive platform for harmonization and technology development in the biopharmaceutical industry. The publication series of which this paper is a part describes NIST's overall control strategy to ensure NISTmAb quality and availability over its lifecycle. In this paper, the development and qualification of methods for monitoring NISTmAb charge heterogeneity are described. Capillary zone electrophoresis (CZE) and capillary isoelectric focusing (CIEF) assays were optimized and evaluated as candidate assays for NISTmAb quality control. CIEF was found to be suitable as a structural characterization assay yielding information on the apparent pI of the NISTmAb. CZE was found to be better suited for routine monitoring of NISTmAb charge heterogeneity and was qualified for this purpose. This paper is intended to provide relevant details of NIST's charge heterogeneity control strategy to facilitate implementation of the NISTmAb as a test molecule in the end user's laboratory. Graphical Abstract Representative capillary zone electropherogram of the NIST monoclonal antibody (NISTmAb). The NISTmAb is a publicly available research tool intended to facilitate advancement of biopharmaceutical analytics.

  19. Thermal neutron flux distribution in ET-RR-2 reactor thermal column

    Directory of Open Access Journals (Sweden)

    Imam Mahmoud M.

    2002-01-01

    Full Text Available The thermal column in the ET-RR-2 reactor is intended to promote a thermal neutron field of high intensity and purity to be used for following tasks: (a to provide a thermal neutron flux in the neutron transmutation silicon doping, (b to provide a thermal flux in the neutron activation analysis position, and (c to provide a thermal neutron flux of high intensity to the head of one of the beam tubes leading to the room specified for boron thermal neutron capture therapy. It was, therefore, necessary to determine the thermal neutron flux at above mentioned positions. In the present work, the neutron flux in the ET-RR-2 reactor system was calculated by applying the three dimensional diffusion depletion code TRITON. According to these calculations, the reactor system is composed of the core, surrounding external irradiation grid, beryllium block, thermal column and the water reflector in the reactor tank next to the tank wall. As a result of these calculations, the thermal neutron fluxes within the thermal column and at irradiation positions within the thermal column were obtained. Apart from this, the burn up results for the start up core calculated according to the TRITION code were compared with those given by the reactor designer.

  20. 78 FR 54149 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2013-09-03

    ...We are superseding airworthiness directive (AD) 2012-10-12 for all RR RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2- 61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. AD 2012-10-12 required inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for cracks. We are issuing this AD to require inspections of the IP compressor rotor shaft, as required by AD 2012- 10-12, to add on-wing inspections for the Trent 500 engines, and to add on-wing and in-shop inspections for the Trent 900 engines. This AD was prompted by detection of a crack in a Trent 500 IP compressor rotor shaft rear balance land during a shop visit. Further engineering evaluation, done by RR, concluded that the cracking may also exist in Trent 900 engines. We are issuing this AD to detect cracking on the IP compressor rotor shaft rear balance land, which could lead to uncontained engine failure and damage to the airplane.

  1. Properties of Asymmetric Detrended Fluctuation Analysis in the time series of RR intervals

    Science.gov (United States)

    Piskorski, J.; Kosmider, M.; Mieszkowski, D.; Krauze, T.; Wykretowicz, A.; Guzik, P.

    2018-02-01

    Heart rate asymmetry is a phenomenon by which the accelerations and decelerations of heart rate behave differently, and this difference is consistent and unidirectional, i.e. in most of the analyzed recordings the inequalities have the same directions. So far, it has been established for variance and runs based types of descriptors of RR intervals time series. In this paper we apply the newly developed method of Asymmetric Detrended Fluctuation Analysis, which so far has mainly been used with economic time series, to the set of 420 stationary 30 min time series of RR intervals from young, healthy individuals aged between 20 and 40. This asymmetric approach introduces separate scaling exponents for rising and falling trends. We systematically study the presence of asymmetry in both global and local versions of this method. In this study global means "applying to the whole time series" and local means "applying to windows jumping along the recording". It is found that the correlation structure of the fluctuations left over after detrending in physiological time series shows strong asymmetric features in both magnitude, with α+ physiological data after shuffling or with a group of symmetric synthetic time series.

  2. Toothpick test: a methodology for the detection of RR soybean plants1

    Directory of Open Access Journals (Sweden)

    Fabiana Mota da Silva

    Full Text Available Due to the large increase in the area cultivated with genetically modified soybean in Brazil, it has become necessary to determine methods that are fast and efficient for detecting these cultivars. The aim of this work was to test the efficiency of the toothpick method in the detection of RR soybean plants, as well as to distinguish between cultivars, for sensitivity caused by herbicide. Ten transgenic soybean cultivars, resistant to the active ingredient glyphosate, and ten conventional soybean cultivars were used. Toothpicks soaked in glyphosate were applied to all the plants at stage V6 and evaluations were made at 2, 4, 6, 8 and 10 days after application (DAA. The effects of the glyphosate on the cultivars, and the symptoms of phytotoxicity caused in the transgenic plants were evaluated by means of grading scales. The toothpick test is effective in identifying RR soybean cultivars and also in separating them into groups by sensitivity to the symptoms caused by the glyphosate.

  3. Optimization of Exopolysaccharide Production by Lactobacillus delbrueckii subsp. bulgaricus RR Grown in a Semidefined Medium

    Science.gov (United States)

    Kimmel, Stacy A.; Roberts, Robert F.; Ziegler, Gregory R.

    1998-01-01

    The optimal fermentation temperature, pH, and Bacto-casitone (Difco Laboratories, Detroit, Mich.) concentration for production of exopolysaccharide by Lactobacillus delbrueckii subsp. bulgaricus RR in a semidefined medium were determined by using response surface methods. The design consisted of 20 experiments, 15 unique combinations, and five replications. All fermentations were conducted in a fermentor with a 2.5-liter working volume and were terminated when 90% of the glucose in the medium had been consumed. The population of L. delbrueckii subsp. bulgaricus RR and exopolysaccharide content were measured at the end of each fermentation. The optimum temperature, pH, and Bacto-casitone concentration for exopolysaccharide production were 38°C, 5, and 30 g/liter, respectively, with a predicted yield of 295 mg of exopolysaccharide/liter. The actual yield under these conditions was 354 mg of exopolysaccharide/liter, which was within the 95% confidence interval (217 to 374 mg of exopolysaccharide/liter). An additional experiment conducted under optimum conditions showed that exopolysaccharide production was growth associated, with a specific production at the endpoint of 101.4 mg/g of dry cells. Finally, to obtain material for further characterization, a 100-liter fermentation was conducted under optimum conditions. Twenty-nine grams of exopolysaccharide was isolated from centrifuged, ultrafiltered fermentation broth by ethanol precipitation. PMID:9464404

  4. Photometric long-term variations and superhump occurrence in the Classical Nova RR Pictoris

    Science.gov (United States)

    Fuentes-Morales, I.; Vogt, N.; Tappert, C.; Schmidtobreick, L.; Hambsch, F.-J.; Vučković, M.

    2018-02-01

    We present an analysis of all available time-resolved photometry from the literature and new light curves obtained in 2013-2014 for the old nova RR Pictoris. The well-known hump light curve phased with the orbital period reveals significant variations over the last 42 yr in shape, amplitude and other details which apparently are caused by long-term variations in the disc structure. In addition, we found evidence for the presence of superhumps in 2007, with the same period ( ˜ 9 per cent longer than the orbital period), as reported earlier by other authors from observations in 2005. Possibly, superhumps arise quickly in RR Pic, but are sporadic events, because in all the other observing runs analysed no significant superhump signal was detected. We also determined an actual version of the Stolz-Schoembs relation between superhump period and orbital period, analysing separately dwarf novae, classical novae and nova-like stars, and conclude that this relation is of general validity for all superhumpers among the cataclysmic variables (CVs), in spite of small but significant differences among the sub-types mentioned above. We emphasize the importance of such a study in context with the still open question of the interrelation between the different sub-classes of CVs, crucial for our understanding of the long-term CV evolution.

  5. Ab initio design of coherent thermal sources

    Science.gov (United States)

    Drevillon, Jérémie; Ben-Abdallah, Philippe

    2007-12-01

    Emission of thermal light from a hot body has been considered for a long time as broadband and quasi-isotropic. Today, we know that this paradigm is wrong and it has been shown that many micro- and nanostructured materials are able to radiate in narrow spectral bands and around specific directions of space. However, so far, only heuristic strategies based on trial and error have been followed for engineering such sources. Here, we present a general method for the ab initio design of coherent thermal sources by using only the first principles of optics. Our results pave the way toward the inverse design of new composite emitting structures for high performance applications in optics.

  6. Ab initio electronic stopping power in materials

    International Nuclear Information System (INIS)

    Shukri, Abdullah-Atef

    2015-01-01

    The average energy loss of an ion per unit path length when it is moving through the matter is named the stopping power. The knowledge of the stopping power is essential for a variety of contemporary applications which depend on the transport of ions in matter, especially ion beam analysis techniques and ion implantation. Most noticeably, the use of proton or heavier ion beams in radiotherapy requires the knowledge of the stopping power. Whereas experimental data are readily available for elemental solids, the data are much more scarce for compounds. The linear response dielectric formalism has been widely used in the past to study the electronic stopping power. In particular, the famous pioneering calculations due to Lindhard evaluate the electronic stopping power of a free electron gas. In this thesis, we develop a fully ab initio scheme based on linear response time-dependent density functional theory to predict the impact parameter averaged quantity named the random electronic stopping power (RESP) of materials without any empirical fitting. The purpose is to be capable of predicting the outcome of experiments without any knowledge of target material besides its crystallographic structure. Our developments have been done within the open source ab initio code named ABINIT, where two approximations are now available: the Random-Phase Approximation (RPA) and the Adiabatic Local Density Approximation (ALDA). Furthermore, a new method named 'extrapolation scheme' have been introduced to overcome the stringent convergence issues we have encountered. These convergence issues have prevented the previous studies in literature from offering a direct comparison to experiment. First of all, we demonstrate the importance of describing the realistic ab initio electronic structure by comparing with the historical Lindhard stopping power evaluation. Whereas the Lindhard stopping power provides a first order description that captures the general features of the

  7. Giant magnetoresistance An ab-initio description

    CERN Document Server

    Binder, J

    2000-01-01

    A new theoretical concept to study the microscopic origin of Giant Magnetoresistance (GMR) from first principles is presented. The method is based on ab-initio electronic structure calculations within the spin density functional theory using a Screened KORRINGA-KOHNROSTOKER method. Scattering at impurity atoms in the multilayers is described by means of a GREEN's-function method. The scattering potentials are calculated self-consistently. The transport properties are treated quasi-classically solving the BOLTZMANN equation including the electronic structure of the layered system and the anisotropic scattering. The solution of the BOLTZMANN equation is performed iteratively taking into account both scattering out and scattering in terms (vertex corrections). The method is applied to Co/Cu and Fe/Cr multilayers. Trends of scattering cross sections, residual resistivities and GMR ratios are discussed for various transition metal impurities at different positions in the Co/Cu or Fe/Cr multilayers. Furthermore the...

  8. Absorção de manganês em soja RR sob efeito do glifosate

    Directory of Open Access Journals (Sweden)

    Gabriel José Massoni de Andrade

    2011-06-01

    Full Text Available Foi levantada a hipótese de que o glifosate aplicado à soja resistente ao herbicida poderia alterar a eficiência de absorção e translocação do nutriente na planta. Com o objetivo de estudar o acúmulo e distribuição do Mn, assim como a cinética de absorção de Mn pela soja geneticamente modificada sob efeito da aplicação de glifosate, foram conduzidos dois experimentos. No primeiro, os tratamentos foram constituídos por duas cultivares de soja quase isogênicas cultivadas em solução nutritiva (Conquista e Valiosa RR com aplicação ou não do herbicida. As concentrações de Mn empregadas na solução nutritiva foram: 0; 0,085; 0,125; 0,250; e 0,500 mg L-1. Após 25 dias de cultivo, parte do total de plantas de soja transgênica foi pulverizada com o herbicida. No segundo experimento, para avaliação da cinética de absorção do Mn da cultivar Valiosa RR, as plantas foram pulverizadas com glifosate aos 26 dias de cultivo nas doses de 0, 15 e 960 g ha-1 e.a. Constatou-se que a transgenia para resistência ao herbicida não altera a nutrição mangânica na cultivar de soja Valiosa RR. Mesmo reduzindo a massa de matéria seca de raiz, o glifosate não interfere na absorção e no transporte de Mn na planta de soja transgênica. Quanto à absorção do Mn pela cultivar transgênica, os parâmetros cinéticos Km, Vmáx. e Cmín. não são alterados pelo herbicida aplicado via foliar.

  9. Report on enrichment work at AB Atomenergi, 1965-1978

    International Nuclear Information System (INIS)

    Maartensson, M.

    1978-11-01

    A review of the Rand D performed at AB Atomenergi (now Studsvik Energiteknik AB) in the field of enrichment during the period 1965-1978. The report also describes the international development, and discusses the possibilities for continued Swedish efforts in this area. (L.E.)

  10. CRY 1AB trangenic cowpea obtained by nodal electroporation ...

    African Journals Online (AJOL)

    Electroporation-mediated genetic transformation was used to introduce Cry 1 Ab insecticidal gene into cowpea. Nodal buds were electroporated in planta with a plasmid carrying the Cry 1Ab and antibiotic resistance npt II genes driven by a 35S CaMV promoter. T1 seeds derived from electroporated branches were selected ...

  11. 12 CFR Appendixes A-B to Part 41 - [Reserved

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false [Reserved] A Appendixes A-B to Part 41 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY FAIR CREDIT REPORTING Appendixes A-B to Part 41 [Reserved] ...

  12. Clinicopathological features of type AB thymoma with liver metastases.

    Science.gov (United States)

    Wang, Zhenzheng; Li, Hui; Cao, Hongyan; Zheng, Jinfeng

    2014-01-01

    We studied the clinicopathological features of type AB thymoma with liver metastases and explore the histological types, diagnosis and differential diagnosis, treatment and prognosis for this disease. Liver metastasis specimens were derived from one case of type AB thymoma 5 years after operation and were examined histologically using light microscopy and immunohistochemistry. A comprehensive analysis was performed on the patient's clinical manifestations, histopathology, immunohistochemistry features, differential diagnosis, treatment and prognosis in combination with a review of the relevant literature. Metastases were detected 5 years after initial operation on a 49-year-old, female patient with type AB thymoma. The pathological diagnosis for the liver metastases was type AB thymoma. Immunohistochemistry staining showed CKpan (+), CD3 (+), CD2 (+), TdT (+), CD5 (+), P53 (+), Hep-1 (-), and Ki67-positive cells (25%). The expression level of galectin-3 was higher than in the mediastinal thymoma tissue identified 5 years prior. Liver metastases of type AB thymoma are extremely rare. This case indicated that type AB thymoma with low malignant potential might recur and develop distant metastases. Overexpression of p53, galectin-3 and Ki67 in type AB thymoma might coordinately manipulate the process of development, progression and malignant transformation of type AB thymomas.

  13. Undoing Gender through Legislation and Schooling: The Case of AB 537 and AB 394 in California, USA

    Science.gov (United States)

    Knotts, Greg

    2009-01-01

    This article investigates California laws AB 537: The Student Safety and Violence Prevention Act of 2000, and the recently enacted AB 394: Safe Place to Learn Act. Both demand that gender identity and sexual orientation be added to the lexicon of anti-harassment protection in public education. However, despite these progressive measures, schools…

  14. R-R interval variations influence the degree of mitral regurgitation in dogs with myxomatous mitral valve disease

    DEFF Research Database (Denmark)

    Reimann, M. J.; Moller, J. E.; Haggstrom, J.

    2014-01-01

    of congestive heart failure due to MMVD. The severity of MR was evaluated in apical four-chamber view using colour Doppler flow mapping (maximum % of the left atrium area) and colour Doppler M-mode (duration in ms). The influence of the ratio between present and preceding R-R interval on MR severity......Mitral regurgitation (MR) due to myxomatous mitral valve disease (MMVD) is a frequent finding in Cavalier King Charles Spaniels (CKCSs). Sinus arrhythmia and atrial premature complexes leading to R-R interval variations occur in dogs. The aim of the study was to evaluate whether the duration...... of the RR interval immediately influences the degree of MR assessed by echocardiography in dogs. Clinical examination including echocardiography was performed in 103 privately-owned dogs: 16 control Beagles, 70 CKCSs with different degree of MR and 17 dogs of different breeds with clinical signs...

  15. The Ancient stellar population of Leo A.

    NARCIS (Netherlands)

    Saha, Abhijit; Fiorentino, Giuliana; Tolstoy, Eline; Cole, Andrew

    The primary goal of our proposal is the characterisation of the oldest stellar populations in Leo A using the properties of ancient RR Lyrae variable stars as tracers. Well known and long established correlations exist between the periods and luminosities of RR Lyrae variable stars and their ages

  16. Structural and biophysical characterization of Bacillus thuringiensis insecticidal proteins Cry34Ab1 and Cry35Ab1.

    Directory of Open Access Journals (Sweden)

    Matthew S Kelker

    Full Text Available Bacillus thuringiensis strains are well known for the production of insecticidal proteins upon sporulation and these proteins are deposited in parasporal crystalline inclusions. The majority of these insect-specific toxins exhibit three domains in the mature toxin sequence. However, other Cry toxins are structurally and evolutionarily unrelated to this three-domain family and little is known of their three dimensional structures, limiting our understanding of their mechanisms of action and our ability to engineer the proteins to enhance their function. Among the non-three domain Cry toxins, the Cry34Ab1 and Cry35Ab1 proteins from B. thuringiensis strain PS149B1 are required to act together to produce toxicity to the western corn rootworm (WCR Diabrotica virgifera virgifera Le Conte via a pore forming mechanism of action. Cry34Ab1 is a protein of ∼14 kDa with features of the aegerolysin family (Pfam06355 of proteins that have known membrane disrupting activity, while Cry35Ab1 is a ∼44 kDa member of the toxin_10 family (Pfam05431 that includes other insecticidal proteins such as the binary toxin BinA/BinB. The Cry34Ab1/Cry35Ab1 proteins represent an important seed trait technology having been developed as insect resistance traits in commercialized corn hybrids for control of WCR. The structures of Cry34Ab1 and Cry35Ab1 have been elucidated to 2.15 Å and 1.80 Å resolution, respectively. The solution structures of the toxins were further studied by small angle X-ray scattering and native electrospray ion mobility mass spectrometry. We present here the first published structure from the aegerolysin protein domain family and the structural comparisons of Cry34Ab1 and Cry35Ab1 with other pore forming toxins.

  17. Ab initio phonon scattering by dislocations

    Science.gov (United States)

    Wang, Tao; Carrete, Jesús; van Roekeghem, Ambroise; Mingo, Natalio; Madsen, Georg K. H.

    2017-06-01

    Heat management in thermoelectric and power devices as well as in random access memories poses a grand challenge and can make the difference between a working and an abandoned device design. Despite the prevalence of dislocations in all these technologies, the modeling of their thermal resistance is based on 50-year-old analytical approximations, whose simplicity was driven by practical limitations rather than physical insight. We introduce an efficient ab initio approach based on Green's functions computed by two-dimensional reciprocal space integration. By combining elasticity theory and density functional theory, we calculate the scattering strength of a 90∘ misfit edge dislocation in Si. Because of the breakdown of the Born approximation, earlier literature models fail, even qualitatively. We find that a dislocation density larger than 109cm-2 is necessary to substantially influence thermal conductivity at room temperature and above. We quantify how much of the reduction of thermal conductivity measured in nanograined samples can be explained by realistic dislocation concentrations.

  18. Ab interno trabeculectomy in the adult patient.

    Science.gov (United States)

    SooHoo, Jeffrey R; Seibold, Leonard K; Kahook, Malik Y

    2015-01-01

    Glaucoma is a potentially blinding disease that affects millions of people worldwide. The mainstay of treatment is lowering of intraocular pressure (IOP) through the use of medications, laser and/or incisional surgery. The trabecular meshwork (TM) is thought to be the site of significant resistance to aqueous outflow in open angle glaucoma. Theoretically, an incision through TM or TM removal should decrease this resistance and lead to a significant reduction in IOP. This approach, commonly referred to as goniotomy or trabeculotomy, has been validated in the pediatric population and has been associated with long-term IOP control. In adults, however, removal of TM tissue has been historically associated with more limited and short-lived success. More recent evidence, reveals that even adult patients may benefit significantly from removal of diseased TM tissue and can lead to a significant reduction in IOP that is long-lasting and safe. In this review, we discuss current evidence and techniques for ab interno trabeculectomy using various devices in the adult patient.

  19. Lifshitz invariants from ab initio lattice dynamics

    Science.gov (United States)

    Schiaffino, Andrea; Stengel, Massimiliano

    The interaction between different order parameters is vital to explain the emergence of new functionalities (hybrid improper ferroelectricity, magnetoelectricity) in multiferroic systems. While considerable theoretical efforts have been directed in the past at studying couplings (e.g. trilinear or biquadratic) that occur in a homogeneous sample, recent research has revealed an increasing number of cases where the interesting physics emerges from inhomogeneities in some order parameter (e.g. flexoelectricity, domain walls), rather than the uniform bulk phase itself. These are usually described in phenomenological theories via symmetry-allowed gradient-mediated terms, the so-called Lifshitz invariants. Here I will present a general method to calculate such couplings ab initio, within the framework of density-functional perturbation theory. I will start with a brief overview on the most challenging aspects of these calculations, i.e. how to deal with the breakdown of the translational symmetry, and with the unusual electrostatic effects that occur in such a regime. Next, I will demonstrate this strategy in practice by presenting calculations of the most relevant gradient coefficients involving strain, octahedral tilts and polarization in ferroelastic SrTiO3. MINECO-Spain through Grants No. FIS2013-48668-C2-2-P and No. SEV-2015-0496, and by Generalitat de Catalunya (Grant No. 2014SRG301).

  20. Boiling treatment of ABS and PS plastics for flotation separation.

    Science.gov (United States)

    Wang, Chong-qing; Wang, Hui; Wu, Bao-xin; Liu, Qun

    2014-07-01

    A new physical method, namely boiling treatment, was developed to aid flotation separation of acrylonitrile-butadiene-styrene (ABS) and polystyrene (PS) plastics. Boiling treatment was shown to be effective in producing a hydrophilic surface on ABS plastic. Fourier Transform Infrared analysis was conducted to investigate the mechanism of boiling treatment of ABS. Surface rearrangement of polymer may be responsible for surface change of boiling treated ABS, and the selective influence of boiling treatment on the floatability of boiling treated plastics may be attributed to the difference in the molecular mobility of polymer chains. The effects of flotation time, frother concentration and particle size on flotation behavior of simple plastic were investigated. Based on flotation behavior of simple plastic, flotation separation of boiling treatment ABS and PS with different particle sizes was achieved efficiently. The purity of ABS and PS was up to 99.78% and 95.80%, respectively; the recovery of ABS and PS was up to 95.81% and 99.82%, respectively. Boiling treatment promotes the industrial application of plastics flotation and facilitates plastic recycling. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. AB0 blood subgroup allele frequencies in the Turkish population.

    Science.gov (United States)

    Akbas, Fahri; Aydin, Müge; Cenani, Asim

    2003-09-01

    We determined the AB0 blood group system with a PCR based technique termed APLP (Amplified Product Length Polymorphism) in the Turkish population. The method includes ten different allele specific primers and permits identification of the major AB0 genotypes and its suballeles (A1-A2-B-0A-02-0G-AG). The suballeles were amplified in a single tube reaction. We have determined AB0 phenotypes in 129 Turkish individuals. No significant deviation from the Hardy-Weinberg equilibrium was observed.

  2. [Find your way in the jungle of mAbs].

    Science.gov (United States)

    Watier, H

    2017-09-01

    The rapidly increasing number of approved monoclonal antibodies (mAbs) and the huge number of mAbs in clinical development are a matter of concern for who wants to easily identify targets, indications, mechanisms of action and possible adverse effects. The current nomenclature being of limited interest, simple rationales will be presented for helping practitioners in rapidly classify mAbs depending on their structure-pharmacology relationship and in evaluating their potential effects, particularly in transfusion medicine. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Association between RR interval and high-frequency heart rate variability acquired during short-term, resting recordings with free and paced breathing

    International Nuclear Information System (INIS)

    Sandercock, Gavin; Gladwell, Valerie; Beneke, Ralph; Dawson, Samantha; Nunan, David; Brodie, David

    2008-01-01

    High-frequency (HF) oscillations in RR interval from 0.15–0.40 Hz are widely accepted as a measure of cardiac vagal outflow but the HF/RR relationship appears complex, particularly with longer RR intervals. The aim of this study was to evaluate the HF/RR interval relationship during free and paced breathing. HF power and mean RR interval length were recorded in 150 men and 120 women (mean age 34.5 ± 11.4) during 5 min of supine rest with either free or paced (12 cycles min −1 ) breathing. Linear and quadratic models were used to assess the relationship between RR interval and the natural logarithm of HF power (lnHF). The RR interval length at which there was no further increase in lnHF was determined as the deflection point. ANCOVA was used to determine differences in the linear regression slopes for lnHF/RR with paced or free breathing. With free breathing (n = 131), the adjusted R 2 was similar between linear (15.3%) and quadratic (17.5%) fits and saturation of lnHF occurred within the recorded RR interval range (1326 ms). With paced breathing (n = 139), adjusted R 2 values were again similar between linear (22.4%) and quadratic (23.2%) fits. The deflection point was outside the range of recorded RR intervals at 1458 ms. ANCOVA showed a significant difference in the slope of the lnHF/RR regression lines between free and paced breathing. The lnHF/RR relationship is weaker when derived from between-subject recordings than from repeated within-subject samples. lnHF/RR showed evidence of saturation at ∼45 bpm with free breathing. With paced breathing, a deflection in lnHF was found outside the recorded RR interval range (∼41 bpm). Paced breathing creates a stronger lnHF/RR relationship. The slope of the lnHF/RR regression line with paced breathing is significantly different from that observed with free breathing. It appears that lnHF is a valid index of vagal outflow, except in subjects with very low heart rates. Paced breathing data collection protocols

  4. Revealing strategies of quorum sensing in Azospirillum brasilense strains Ab-V5 and Ab-V6.

    Science.gov (United States)

    Fukami, Josiane; Abrantes, Julia Laura Fernandes; Del Cerro, Pablo; Nogueira, Marco Antonio; Ollero, Francisco Javier; Megías, Manuel; Hungria, Mariangela

    2018-01-01

    Azospirillum brasilense is an important plant-growth promoting bacterium (PGPB) that requires several critical steps for root colonization, including biofilm and exopolysaccharide (EPS) synthesis and cell motility. In several bacteria these mechanisms are mediated by quorum sensing (QS) systems that regulate the expression of specific genes mediated by the autoinducers N-acyl-homoserine lactones (AHLs). We investigated QS mechanisms in strains Ab-V5 and Ab-V6 of A. brasilense, which are broadly used in commercial inoculants in Brazil. Neither of these strains carries a luxI gene, but there are several luxR solos that might perceive AHL molecules. By adding external AHLs we verified that biofilm and EPS production and cell motility (swimming and swarming) were regulated via QS in Ab-V5, but not in Ab-V6. Differences were observed not only between strains, but also in the specificity of LuxR-type receptors to AHL molecules. However, Ab-V6 was outstanding in indole acetic acid (IAA) synthesis and this molecule might mimic AHL signals. We also applied the quorum quenching (QQ) strategy, obtaining transconjugants of Ab-V5 and Ab-V6 carrying a plasmid with acyl-homoserine lactonase. When maize (Zea mays L.) was inoculated with the wild-type and transconjugant strains, plant growth was decreased with the transconjugant of Ab-V5-confirming the importance of an AHL-mediated QS system-but did not affect plant growth promotion by Ab-V6.

  5. Structural characterisation of the exopolysaccharide produced by Lactobacillus delbrückii subspecies bulgaricus rr grown in skimmed milk

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Gruter, M.; Leeflang, B.R.; Kuiper, J.; Kamerling, J.P.

    1993-01-01

    The exopolysaccharide of Lactobacillus delbrückii subsp. bulgaricus rr. isolated from skimmed milk, is a heteropolymer of D-galactopyranosyl, D-glucopyranosyl, and L-rhamnopyranosyl residues in the molar ratio 5:1:1. The structure was established by linkage analysis and 1D and 2D NMR spectroscopy of

  6. 75 FR 49368 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-Trent 900 Series Turbofan Engines

    Science.gov (United States)

    2010-08-13

    ... induction of an engine into the shop for maintenance involving the separation of pairs of major mating... Airworthiness Directives; Rolls-Royce plc (RR) RB211-Trent 900 Series Turbofan Engines AGENCY: Federal Aviation... condition on an aviation product. The MCAI describes the unsafe condition as: Wear, beyond Engine Manual...

  7. 76 FR 30529 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-535 Series Turbofan Engines

    Science.gov (United States)

    2011-05-26

    ... proposed AD to ``For the purpose of this AD, an ``engine shop visit'' is the induction of an engine into... service. Definitions (f) For the purpose of this AD, an ``engine shop visit'' is: (1) Induction of an... Airworthiness Directives; Rolls-Royce plc (RR) RB211-535 Series Turbofan Engines AGENCY: Federal Aviation...

  8. 77 FR 4648 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-535 Series Turbofan Engine

    Science.gov (United States)

    2012-01-31

    ...'' is induction of an engine into the shop for any purpose where: (1) All the blades are removed from... Airworthiness Directives; Rolls-Royce plc (RR) RB211-535 Series Turbofan Engine AGENCY: Federal Aviation... engines. That AD currently requires performing initial and repetitive visual and fluorescent penetrant...

  9. 76 FR 14797 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-Trent 900 Series Turbofan Engines

    Science.gov (United States)

    2011-03-18

    ...: Discussion The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of... Protection System (IPTOS). The purpose of the IPTOS functionality is to detect engine conditions that may.... Applicability (c) This AD applies to RR model RB211-Trent 970-84, 970B-84, 972-84, 972B-84, 977-84, 977B-84, and...

  10. Vasyl' Danylenko, ed. Ukrains'ka intelihentsiia i vlada: Zvedennia sekretnoho viddilu DPU USRR 1927–1929 rr.

    Directory of Open Access Journals (Sweden)

    Olena Palko

    2015-01-01

    Full Text Available Vasyl' Danylenko, ed. Ukrains'ka intelihentsiia i vlada: Zvedennia sekretnoho viddilu DPU USRR 1927–1929 rr. [The Ukrainian Intelligentsia and State Power. Summaries of the Secret Department of State Political Administration of the Ukrainian SSR for 1927–1929]. Kyiv: Tempora, 2012. 756 pp. Illustrations. Appendix. Indexes. 70 UAH, cloth.

  11. Realization of prediction of materials properties by ab initio ...

    Indian Academy of Sciences (India)

    Unknown

    IMR), Tohoku University, Sendai 980-8577, Japan. Abstract. Ab initio treatment is becoming realistic to predict physical, chemical, and even mechanical pro- perties of academically and industrially interesting materials. There is, however, some ...

  12. Cutaneous horn and thermal keratosis in erythema AB igne

    Directory of Open Access Journals (Sweden)

    Sood Apra

    2002-01-01

    Full Text Available A 46 - year - old Kashmiri lady developed erythema ab igne on both legs. She subsequently developed multiple keratoses and a cutaneous horn in the involved skin. An uncommon association of these three clinical conditions is being presented.

  13. Ab initio adiabatic and quasidiabatic potential energy surfaces of H ...

    Indian Academy of Sciences (India)

    s12039-015-1022-8. Ab initio adiabatic and quasidiabatic potential energy surfaces of H. ++. CN system. BHARGAVA ANUSURI and SANJAY KUMAR. ∗. Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India.

  14. Ab Initio Atomistic Thermodynamics for Surfaces: A Primer

    National Research Council Canada - National Science Library

    Rogal, Jutta; Reuter, Karsten

    2006-01-01

    .... These techniques are referred to as first-principles (or in latin: ab initio) to indicate that they do not rely on empirical or fitted parameters, which then makes them applicable for a wide range of realistic conditions...

  15. Genetics Home Reference: GM2-gangliosidosis, AB variant

    Science.gov (United States)

    ... can be inherited? More about Inheriting Genetic Conditions Diagnosis & Management Resources Genetic Testing (1 link) Genetic Testing Registry: Tay-Sachs disease, variant AB General Information from MedlinePlus (5 ...

  16. Study of the conductivity of Nylon 6/ABS blends

    Science.gov (United States)

    Saman, Mansor Mohamad

    In this research project the study was conducted on conductivity of acrylonitrile butadiene styrene (ABS)/Nylon 6 blend with carbon black as conductive filler. Three different blends of ABS/carbon black, Nylon 6/carbon black and ABS/Nylon 6/carbon black with various compositions were prepared by mixing together by using a single screw extruder. Each compound was reblended to achieve homogeneous mixture and the effect of processing was studied.Conductivity of the low resistance of blends were obtained by measuring sheet resistance using four-point probe as according to ASTM F 1529. The sheet resistance could only be detected for ABS/carbon black 20 wt % and above, and ABS/Nylon 6 with 80:20 ratio with 10 wt % of carbon black. Whereas, for Nylon 6/carbon black blends and the others high resistance of blends, their resistances were measured by Teraohmeter according to ASTM D 257 method. Percolation threshold (critical volume fraction) of the blends was studied to find actual conductive filler contents to avoid deterioration of mechanical properties. In this case, tensile tests were conducted according to ASTM D 638 to establish their mechanical properties. Meanwhile, scanning electron microscopy (SEM) was used to study the morphology of blended polymers, interface of polymer/carbon black and aggregation phenomenon between carbon black and polymers. The correlation between conductivity, mechanical properties and morphological characterisation of all the blends was studied.The results show that, the addition of carbon black up to 10%, increases conductivity and tensile strength of ABS/carbon black and Nylon 6/carbon black blends. Conductivity continues to increase with further addition of carbon black, but at the expense of tensile strength reduction due to the effect of brittle nature of carbon black.By adding ABS in ABS/Nylon 6/carbon black blends, conductivity increases, whereas tensile strength decreases. However, tensile strength of ABS/Nylon 6/carbon black blends

  17. Report on the Personnel Dosimetry at AB Atomenergi during 1965

    Energy Technology Data Exchange (ETDEWEB)

    Edvardsson, K.A.

    1966-10-15

    This report presents the results of the personnel dosimetry at AB Atomenergi during 1965. No doses exceeding the recommendations of ICRP were reported. For AB Atomenergi the average external total body dose during the year was 60 mrem which corresponds to 89.4 manrem. 31200 gamma films and 5850 neutron films were evaluated. 2067 urine analyses and 692 measurements of body activity were made.

  18. Rescue of failed filtering blebs with ab interno trephination.

    Science.gov (United States)

    Shihadeh, Wisam A; Ritch, Robert; Liebmann, Jeffrey M

    2006-06-01

    We evaluated the effectiveness of ab interno automated trephination as a technique for rescuing failed mature filtering blebs. A retrospective chart review of 40 failed blebs of 38 patients who had a posttrephination follow-up period of at least 3 months was done. With success defined as intraocular pressure (IOP) control with other modalities of management. Complications were few. We believe that ab interno trephination is an excellent option for rescuing selected failed filtering blebs.

  19. Report on the Personnel Dosimetry at AB Atomenergi during 1965

    International Nuclear Information System (INIS)

    Edvardsson, K.A.

    1966-10-01

    This report presents the results of the personnel dosimetry at AB Atomenergi during 1965. No doses exceeding the recommendations of ICRP were reported. For AB Atomenergi the average external total body dose during the year was 60 mrem which corresponds to 89.4 manrem. 31200 gamma films and 5850 neutron films were evaluated. 2067 urine analyses and 692 measurements of body activity were made

  20. The 2-alkyl-2H-indazole regioisomers of synthetic cannabinoids AB-CHMINACA, AB-FUBINACA, AB-PINACA, and 5F-AB-PINACA are possible manufacturing impurities with cannabimimetic activities

    OpenAIRE

    Longworth, Mitchell; Banister, Samuel D.; Mack, James B. C.; Glass, Michelle; Connor, Mark; Kassiou, Michael

    2016-01-01

    Indazole-derived synthetic cannabinoids (SCs) featuring an alkyl substituent at the 1-position and l-valinamide at the 3-carboxamide position (e.g., AB-CHMINACA) have been identified by forensic chemists around the world, and are associated with serious adverse health effects. Regioisomerism is possible for indazole SCs, with the 2-alkyl-2H-indazole regioisomer of AB-CHMINACA recently identified in SC products in Japan. It is unknown whether this regiosiomer represents a manufacturing impurit...

  1. 76 FR 65136 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2011-10-20

    ...We propose to supersede an existing airworthiness directive (AD) that applies to all RR model RB211-524G2-T-19, -524G3-T-19, -524H- T-36, and -524H2-T-19; and RB211-Trent 553-61, 553A2-61, 556-61, 556A2- 61, 556B-61, 556B2-61, 560-61, 560A2-61; RB211-Trent 768-60, 772-60, 772B-60; and RB211-Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B- 17, and 895-17 turbofan engines that have a high-pressure (HP) compressor stage 1 to 4 rotor disc with a part number (P/N) listed in Table 1 of this proposed AD. The existing AD currently requires repetitive inspections of the axial dovetail slots, and follow-on corrective action depending on findings. Since we issued that AD, we determined that the definition of shop visit is too restrictive in the existing AD. This proposed AD would continue to require those repetitive inspections and follow-on corrective actions, and it would change the definition of a shop visit to be less restrictive. We are proposing this AD to detect cracks in the HP compressor stage 1 and 2 disc posts, which could result in failure of the disc post and HP compressor blades, release of uncontained engine debris, and damage to the airplane.

  2. 76 FR 64283 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2011-10-18

    ...We propose to supersede an existing airworthiness directive (AD) that applies to all RR RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. The existing AD currently requires inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for cracks. Since we issued that AD, we received reports of one RB211-Trent 700 and two additional RB211-Trent 800 IP compressor rotor shafts that have been found cracked. This proposed AD would continue to require initial inspections, add additional inspections, and an optional terminating action. The cracking identified above could lead to IP compressor rotor shaft failure, uncontained engine failure, and damage to the airplane. We are proposing this AD to correct the unsafe condition on these products.

  3. 77 FR 2932 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2012-01-20

    ...We are revising an earlier proposed airworthiness directive (AD) for all RR RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B- 61, 556B2-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877- 17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. That NPRM proposed to supersede an existing AD that requires inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for cracks, which could lead to engine failure. This action revises that NPRM by changing the optional terminating action for RB211-Trent 700 and RB211-Trent 800 engines to mandatory terminating action. Since these actions impose an additional burden over that proposed in the NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.

  4. 77 FR 31176 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2012-05-25

    ...We are superseding an existing airworthiness directive (AD) for all RR RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. That AD currently requires inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for cracks. This new AD continues to require initial inspections, adds additional inspections, and a mandatory terminating action. This AD was prompted by additional cracking on RB211-Trent 700 and RB211-Trent 800 IP compressor rotor shafts found since the existing AD was issued. We are issuing this AD to detect cracking on the IP compressor rotor rear balance land. IP compressor rotor rear balance land cracking can lead to uncontained failure of the rotor and damage to the airplane.

  5. POPULARIZING EPIC NARRATIVE IN GEORGE R.R. MARTIN'S A GAME OF THRONES

    Directory of Open Access Journals (Sweden)

    Ida Rochani Adi

    2012-11-01

    Full Text Available This research is intended to show the sustainability of epic in latest years of human history through the most phenomenal fantasy in American literature, A Game of Thrones. Along with the capability of human beings in thinking dearly and sensibly, it is commonsensical that people tend to free themselves from irrationality. The reality shows, however, that the existence of epic fantasy still has power in appealing audiences or readers. This is the case with A Game of Thrones written by George RR Martin who was given the award of One of The Most Influential People in 2011 by Time magazine. This qualitative march, using genre approach, finds out that in order to be compatible with today's society, an epic seen in A Game of Thrones, which is commonly known as a story centering on the legendary hero and his heroic deed in oral folk tradition, keeps its power as an epic fantasy narrative through certain archetypes and formulas. Through genre analysis using semiotic approach, the research brings about conclusions that the elements of high fantasy, elements built through rational representation, and a smart combination of convention and invention brings about its popularity. It is also concluded that there is a close relationship between the myth and the mode of people living even in the most modern context.

  6. Degradation and detoxification of disperse dye Scarlet RR by Galactomyces geotrichum MTCC 1360.

    Science.gov (United States)

    Jadhav, S U; Ghodake, G S; Telke, A A; Tamboli, D P; Govindwar, S P

    2009-04-01

    Galactomyces geotrichum MTCC 1360 degraded the Scarlet RR (100 mg/l) dye within 18 h, under shaking conditions (150 rpm) in malt yeast medium. The optimum pH and the temperature for decolorization were pH 12 and 50 degrees , respectively. Enzymatic studies revealed an induction of the enzymes, including flavin reductase during the initial stage and lignin peroxidase after complete decolorization of the dye. Decolorization of the dye was induced by the addition of CaCO3 to the medium. EDTA had an inhibitory effect on the dye decolorization along with the laccase activity. The metabolites formed after complete decolorization were analyzed by UV-VIS, HPLC, and FTIR. The GC/MS identification of 3 H quinazolin-4- one, 2-ethylamino-acetamide, 1-chloro-4-nitro-benzene, N- (4-chloro-phenyl)-hydroxylamine, and 4-chloro-pheny-lamine as the final metabolites corroborated with the degradation pathway is suggested to understand the mechanism used by G.geotrichum and thereby aiding development of technologies for the application of this organism to the cleaning-up of aquatic and terrestrial environments.

  7. Epigenetic regulation of individual modules of the immunoglobulin heavy chain locus 3’ regulatory region (3’ RR

    Directory of Open Access Journals (Sweden)

    Barbara K Birshtein

    2014-04-01

    Full Text Available The Igh locus undergoes an amazing array of DNA rearrangements and modifications during B cell development. During early stages, the variable region gene is constructed from constituent variable (V, diversity (D and joining (J segments (VDJ joining. B cells that successfully express an antibody can be activated, leading to somatic hypermutation (SHM focused on the variable region, and class switch recombination (CSR, which substitutes downstream constant region genes for the originally used Cμ constant region gene. Many investigators, ourselves included, have sought to understand how these processes specifically target the Igh locus and avoid other loci and potential deleterious consequences of malignant transformation. Our laboratory has concentrated on a complex regulatory region (RR that is located downstream of Cα, the most 3’ of the Igh constant region genes. The ~40 kb 3’ RR, which is predicted to serve as a downstream major regulator of the Igh locus, contains two distinct segments: an ~28 kb region of four enhancers and an adjacent ~12 kb region containing multiple CTCF and Pax5 binding sites. Analysis of targeted mutations in mice by a number of investigators has concluded that the entire 3’ RR enhancer region is essential for SHM and CSR (but not for VDJ joining and for high levels of expression of multiple isotypes. The CTCF/Pax5 binding region is a candidate for influencing VDJ joining early in B cell development and serving as a potential insulator of the Igh locus. Components of the 3’ RR are subject to a variety of epigenetic changes during B cell development, i.e., DNAse I hypersensitivity, histone modifications and DNA methylation, in association with transcription factor binding. We propose that these changes provide a foundation by which regulatory elements in modules of the 3’ RR function by interacting with each other and with target sequences of the Igh locus.

  8. Development of orthogonal NISTmAb size heterogeneity control methods.

    Science.gov (United States)

    Turner, Abigail; Yandrofski, Katharina; Telikepalli, Srivalli; King, Jason; Heckert, Alan; Filliben, James; Ripple, Dean; Schiel, John E

    2018-03-01

    The NISTmAb is a monoclonal antibody Reference Material from the National Institute of Standards and Technology; it is a class-representative IgG1κ intended to serve as a pre-competitive platform for harmonization and technology development in the biopharmaceutical industry. The publication series of which this paper is a part describes NIST's overall control strategy to ensure NISTmAb quality and availability over its lifecycle. In this paper, the development of a control strategy for monitoring NISTmAb size heterogeneity is described. Optimization and qualification of size heterogeneity measurement spanning a broad size range are described, including capillary electrophoresis-sodium dodecyl sulfate (CE-SDS), size exclusion chromatography (SEC), dynamic light scattering (DLS), and flow imaging analysis. This paper is intended to provide relevant details of NIST's size heterogeneity control strategy to facilitate implementation of the NISTmAb as a test molecule in the end user's laboratory. Graphical abstract Representative size exclusion chromatogram of the NIST monoclonal antibody (NISTmAb). The NISTmAb is a publicly available research tool intended to facilitate advancement of biopharmaceutical analytics. HMW = high molecular weight (trimer and dimer), LMW = low molecular weight (2 fragment peaks). Peak labeled buffer is void volume of the column from L-histidine background buffer.

  9. Ab initio no core shell model

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Bruce R. [Univ. of Arizona, Tucson, AZ (United States); Navrátil, Petr [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vary, James P. [Ames Lab. and Iowa State Univ., Ames, IA (United States)

    2012-11-17

    A long-standing goal of nuclear theory is to determine the properties of atomic nuclei based on the fundamental interactions among the protons and neutrons (i.e., nucleons). By adopting nucleon-nucleon (NN), three-nucleon (NNN) and higher-nucleon interactions determined from either meson-exchange theory or QCD, with couplings fixed by few-body systems, we preserve the predictive power of nuclear theory. This foundation enables tests of nature's fundamental symmetries and offers new vistas for the full range of complex nuclear phenomena. Basic questions that drive our quest for a microscopic predictive theory of nuclear phenomena include: (1) What controls nuclear saturation; (2) How the nuclear shell model emerges from the underlying theory; (3) What are the properties of nuclei with extreme neutron/proton ratios; (4) Can we predict useful cross sections that cannot be measured; (5) Can nuclei provide precision tests of the fundamental laws of nature; and (6) Under what conditions do we need QCD to describe nuclear structure, among others. Along with other ab initio nuclear theory groups, we have pursued these questions with meson-theoretical NN interactions, such as CD-Bonn and Argonne V18, that were tuned to provide high-quality descriptions of the NN scattering phase shifts and deuteron properties. We then add meson-theoretic NNN interactions such as the Tucson-Melbourne or Urbana IX interactions. More recently, we have adopted realistic NN and NNN interactions with ties to QCD. Chiral perturbation theory within effective field theory ({chi}EFT) provides us with a promising bridge between QCD and hadronic systems. In this approach one works consistently with systems of increasing nucleon number and makes use of the explicit and spontaneous breaking of chiral symmetry to expand the strong interaction in terms of a dimensionless constant, the ratio of a generic small momentum divided by the chiral symmetry breaking scale taken to be about 1 GeV/c. The

  10. Study on Exothermic Oxidation of Acrylonitrile-butadiene-styrene (ABS Resin Powder with Application to ABS Processing Safety

    Directory of Open Access Journals (Sweden)

    Jenq-Renn Chen

    2010-08-01

    Full Text Available Oxidative degradation of commercial grade ABS (Acrylonitrile-butadiene-styrene resin powders was studied by thermal analysis. The instabilities of ABS containing different polybutadiene (PB contents with respect to temperature were studied by Differential Scanning Calorimeter (DSC. Thermograms of isothermal test and dynamic scanning were performed. Three exothermic peaks were observed and related to auto-oxidation, degradation and oxidative decomposition, respectively. Onset temperature of the auto-oxidation was determined to be around 193 °C. However, threshold temperature of oxidation was found to be as low as 140 °C by DSC isothermal testing. Another scan of the powder after degeneration in air showed an onset temperature of 127 °C. Reactive hazards of ABS powders were verified to be the exothermic oxidation of unsaturated PB domains, not the SAN (poly(styrene-acrylonitrile matrix. Heat of oxidation was first determined to be 2,800 ± 40 J per gram of ABS or 4,720 ± 20 J per gram of PB. Thermal hazards of processing ABS powder are assessed by adiabatic temperature rise at process conditions. IR spectroscopy associated with heat of oxidation verified the oxidative mechanism, and these evidences excluded the heat source from the degradation of SAN. A specially prepared powder of ABS without adding anti-oxidant was analyzed by DSC for comparing the exothermic behaviors. Exothermic onset temperatures were determined to be 120 °C and 80 °C by dynamic scanning and isothermal test, respectively. The assessment successfully explained fires and explosions in an ABS powder dryer and an ABS extruder.

  11. Polycarbonate and co-continuous polycarbonate/ABS blends: influence of notch radius

    NARCIS (Netherlands)

    Inberg, J.P.F.; Gaymans, R.J.

    2002-01-01

    The influence of notch tip radius in the range of 1–0.002 mm was studied on polycarbonate (PC) and co-continuous PC/acrylonitrile–butadiene–styrene (ABS). Co-continuous PC/ABS blend was obtained by mixing PC and ABS containing 15% polybutadiene (PB) in a twin screw extruder. PC and PC/ABS specimens

  12. 77 FR 13483 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2012-03-07

    ...We are superseding an existing airworthiness directive (AD) for all RR model RB211-524G2-T-19, -524G3-T-19, -524H-T-36, and -524H2- T-19; and RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61 556B2-61, 560-61, 560A2-61; RB211-Trent 768-60, 772-60, 772B-60; and RB211-Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895- 17 turbofan engines that have a high-pressure (HP) compressor stage 1 to 4 rotor disc with a part number (P/N) listed in Table 1 of the AD. That AD currently requires repetitive inspections of the axial dovetail slots, and follow-on corrective action depending on findings. Since we issued that AD, we determined that the definition of shop visit is too restrictive in the existing AD. This continues to require those repetitive inspections and follow-on corrective actions. This new AD changes the definition of a shop visit to be less restrictive. This AD was prompted by our determination that the definition of ``shop visit'' in the existing AD is too restrictive, in that it would require operators to inspect more often than required to ensure safety. We are issuing this AD to detect cracks in the HP compressor stage 1 and 2 disc posts, which could result in failure of the disc post and HP compressor blades, release of uncontained engine debris, and damage to the airplane.

  13. Global longitudinal strain corrected by RR interval is a superior predictor of all-cause mortality in patients with systolic heart failure and atrial fibrillation

    DEFF Research Database (Denmark)

    Modin, Daniel; Sengeløv, Morten; Jørgensen, Peter Godsk

    2018-01-01

    failure (HFrEF) with AF remains unknown. This study investigates the prognostic value of RR interval-corrected peak global longitudinal strain {GLSc = GLS/[RR^(1/2)]} in relation to all-cause mortality in HFrEF patients displaying AF during echocardiographic examination. METHODS AND RESULTS......: Echocardiograms from 151 patients with HFrEF and AF during examination were analysed offline. Peak global longitudinal strain (GLS) was averaged from 18 myocardial segments obtained from three apical views. GLS was indexed with the square root of the RR interval {GLSc = GLS/[RR^(1/2)]}. Endpoint was all......-cause mortality. During a median follow-up of 2.7 years, 40 patients (26.5%) died. Neither uncorrected GLS (P = 0.056) nor left ventricular ejection fraction (P = 0.053) was significantly associated with all-cause mortality. After RR^(1/2) indexation, GLSc became a significant predictor of all-cause mortality...

  14. TITRATION METHOD OF AB0 ANTIBODIES WITH THE USE OF MODERN GEL TECHNOLOGY IN AB0-INCOMPATIBLE TRANSPLANTATION

    Directory of Open Access Journals (Sweden)

    A. K. Porunova

    2014-01-01

    Full Text Available It is shown that developed method of titrating AB0 antibodies allows defi ning the titer of the investigational antibodies more precisely on 1–3 dilution of serum compared to the prototype method (titration method of antibodiesin saline medium on the plane. It is more obvious as it excludes hardly interpretable results due to the possibility of conducting visual assessment of agglutination reaction in the gel card thick column and requires less time foranalysis. The results can be saved for comparison with the results of further research. That is not possible under prototype titration method. Aim: our aim is to create a laboratory technique that can accurately, reliably and clearly produce titration of AB0 system antibodies, including in patients with low initial concentration of agglutinins in the blood; a technique more economical in terms of spending serum and that takes less time.Materials and methods: those modes were empirically chosen which allow titration of AB0 system agglutinins using gel technology based micro typing; to titer group antibodies 1640 serum assays of recipients in AB0-incompatibletransplantation were analyzed.The result of the use of specially developed method in organ transplantation from incompatible blood donors consists in enhancing accuracy, sensitivity of natural, complete and incomplete AB0 system immune antibodies titration, in its clarity, using of blood micro-doses for earlier detection of sensitizing of the patient, which is especially important in Pediatrics. Conclusion: the developed procedure of AB0-antibodies’ titration using modern gel technology makes possible a more precise monitoring of the titer of antibodies that is necessary to predict the graft rejection risk, to select the Protocol of preoperative preparation and postoperative management of patients, to assess the effectiveness of therapy in patients for whom it is diffi cult to fi nd a compatible blood type donor, and for whom today AB

  15. Um exemplo de análise contrastiva: o grafema r/rr em português e italiano

    Directory of Open Access Journals (Sweden)

    Lúcia Fulgêncio

    2011-10-01

    Full Text Available Neste trabalho é apresentado um exemplo de análise contrastiva entre a língua italiana e o português falado no Brasil, do ponto de vista fonético. Tomam-se os sons grafados ou <rr> e examinam-se as suas possibilidades re realização fonética em cada língua, individualmente, identificando o contexto de produção de cada realização fonológica. Posteriormente, comparam-se os sistemas fonológicos das duas línguas quanto a esse aspecto, indicando os ambientes de simetria ou dissimetria estrutural. A evidência dos ambientes onde ocorre dissimetria na realização de /<rr> pode ser útil para o professor de italiano para brasileiros (ou vice-versa, já que provavelmente esses ambientes constituirão pontos de maior dificuldade na aprendizagem da produção.In questo studio si presenta un essempio di analisi contrastiva a livello fonetico tra la ligua italiana e quella portoghese parlata in Brasile. Per ognuna delle due lingue vengono analizzate le possibilità di realizzazione fonetica dei grafemi o <rr> definendo il contesto di ogni realizzazione fonologica. In seguito sono comparati i sistemi fonologici dell’italiano e del portoghese per quanto concerne il tema proposto, e vengono indicati gli ambienti di simmetria e asimmetria strutturale. Mettere in risalto gli ambienti di asimmetria nella realizzazione di /<rr> può riverlarsi di grande utilità al professore di italiano a brasiliani o viceversa, dato che l’apprendimento dei suoni che ne risulta costituisce, probabilmente, non poca difficoltà.

  16. 76 FR 65997 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-535 Series Turbofan Engines

    Science.gov (United States)

    2011-10-25

    ...'' is induction of an engine into the shop for any purpose where: (1) All the blades are removed from...) RB211-535 Series Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... applies to all RR RB211-535E4-37, -535E4-B-37, -535E4-B-75, and -535E4-C-37 turbofan engines. The existing...

  17. 40 CFR 174.506 - Bacillus thuringiensis Cry34Ab1 and Cry35Ab1 proteins in corn; exemption from the requirement of...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Bacillus thuringiensis Cry34Ab1 and... Bacillus thuringiensis Cry34Ab1 and Cry35Ab1 proteins in corn are exempted from the requirement of a... REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.506 Bacillus...

  18. Cloning and expression analysis of transcription factor RrTTG1 related to prickle development in rose (Rosa Rugosa

    Directory of Open Access Journals (Sweden)

    Feng Li-Guo

    2015-01-01

    Full Text Available A prickle is an acuminate protuberance formed by the deformation of plant trichomes together with a few cortical cells. It is a type of multicellular eglandular trichome with special morphology, which originates from the phloem but is not connected to the xylem. Rosa rugosa is an important ornamental/commercial plant and an important raw material in the food and perfume industries. However, the firm prickles on its stems are inconvenient to field management, the harvesting of flowers and garden management. The TTG1 transcription factor related to the development of prickle was isolated from R. rugosa in the present study. Its expression patterns in different tissues and varieties were analyzed. Results showed the expression level of the RrTTG1 gene was highest in the leaves, followed by the stems, but was lower in the pericarps and petals. Moreover, the higher expression level of the RrTTG1 gene in all tissues of the ‘Ciguo rose’, as compared with that of the ‘Weihai wild rose’, follows the results of field morphological observation. Therefore, the RrTTG1 transcription factor is likely to regulate the development of rose prickles. This study allows for further discussion on the molecular mechanisms of prickle formation and development in R. rugosa and provides a molecular basis for the cultivation of roses with fewer or no prickles via genetic engineering.

  19. ABS 3D printed solutions for cryogenic applications

    Science.gov (United States)

    Bartolomé, E.; Bozzo, B.; Sevilla, P.; Martínez-Pasarell, O.; Puig, T.; Granados, X.

    2017-03-01

    3D printing has become a common, inexpensive and rapid prototyping technique, enabling the ad hoc fabrication of complex shapes. In this paper, we demonstrate that 3D printed objects in ABS can be used at cryogenic temperatures, offering flexible solutions in different fields. Firstly, a thermo-mechanical characterization of ABS 3D printed specimens at 77 K is reported, which allowed us to delimit the type of cryogenic uses where 3D printed pieces may be implemented. Secondly, we present three different examples where ABS 3D printed objects working at low temperatures have provided specific solutions: (i) SQUID inserts for angular magnetometry (low temperature material characterization field); (ii) a cage support for a metamaterial ;magnetic concentrator; (superconductivity application), and (iii) dedicated tools for cryopreservation in assisted reproductive techniques (medicine field).

  20. Control Performance of Vehicle Abs Featuring ER Valve Pressure Modulator

    Science.gov (United States)

    Cho, M. S.; Choi, S. B.; Wereley, N. M.

    In this work, an electrically controllable anti-lock brake system (ABS) for passenger vehicle is developed by utilizing electrorheological (ER) fluid. A pressure modulator which consists of a cylindrical ER valve and the hydraulic booster is constructed in order to achieve sufficient brake pressure variation during ABS operation. The principal design parameters of the modulator are determined by considering ER properties as well as required braking pressure. After investigating pressure controllability of the modulator, a vehicle model which is integrated with the proposed pressure modulator is formulated to design yaw rate controller. A sliding mode controller is designed to obtain desired yaw rate, and the friction forces between roads and wheels are estimated via the estimator. Braking performances of the proposed ABS under various roads are evaluated through the hardware-in-the-loop-simulation (HILS) and the steering stability during braking operation is demonstrated by undertaking split-μ test.

  1. Wheel slip control of ABS using ER valve pressure modulator

    Science.gov (United States)

    Choi, Seung-Bok; Cho, Myung-Soo; Kim, Yong-Il; Choi, Young-Tai; Wereley, Norman M.

    2004-07-01

    This paper presents a wheel slip control via sliding mode controller for a new anti-lock brake system (ABS) of a passenger vehicle using electrorheological (ER) valve pressure modulator. The principal design parameters of the ER valves and hydraulic booster are appropriately determined by considering braking pressure variation during ABS operation. An electrically controllable pressure modulator using the ER valves is then constructed and its governing equations are derived. Subsequently, the pressure control performance of the new pressure modulator is experimentally evaluated. The governing equations of motion for a quarter car wheel model are derived and the sliding mode controller is formulated for wheel slip control. Hardware in the loop simulation (HILS) for braking performance evaluation is undertaken in order to demonstrate the effectiveness of the proposed ABS associated with the ER valve pressure modulator.

  2. Ab initio simulation of transport phenomena in rarefied gases.

    Science.gov (United States)

    Sharipov, Felix; Strapasson, José L

    2012-09-01

    Ab initio potentials are implemented into the direct simulation Monte Carlo (DSMC) method. Such an implementation allows us to model transport phenomena in rarefied gases without any fitting parameter of intermolecular collisions usually extracted from experimental data. Applying the method proposed by Sharipov and Strapasson [Phys. Fluids 24, 011703 (2012)], the use of ab initio potentials in the DSMC requires the same computational efforts as the widely used potentials such as hard spheres, variable hard sphere, variable soft spheres, etc. At the same time, the ab initio potentials provide more reliable results than any other one. As an example, the transport coefficients of a binary mixture He-Ar, viz., viscosity, thermal conductivity, and thermal diffusion factor, have been calculated for several values of the mole fraction.

  3. Student Measurements of STFA 10AB (Theta Tauri)

    Science.gov (United States)

    Gillette, Sean; Estrada, Chris; Estrada, Reed; Aguilera, Sophia; Chavez, Valerie; Givens, Jalynn; Lindorfer, Sarah; Michels, Kaylie; Mobley, Makenzie; Reder, Gabriel; Renteria, Kayla; Shattles, Jenna; Wilkin, Aiden; Woodbury, Maisy; Rhoades, Breauna; Rhoades, Mark

    2017-04-01

    Eighth grade students at Vanguard Preparatory School measured the double star STFA 10AB using a 22-inch Newtonian Alt/Az telescope and a Celestron Micro Guide eyepiece. Bellatrix was used as the calibration star. The calculated means of multiple observations of STFA 10AB resulted in a separation of 45.18,” a scale constant of 7.88 arcseconds per division, and position angle of 257.9°. These measurements were compared to the most recent values in the Washington Double Star Catalog.

  4. Simplest AB-Thermonuclear Space Propulsion and Electric Generator

    OpenAIRE

    Bolonkin, Alexander

    2007-01-01

    The author applies, develops and researches mini-sized Micro- AB Thermonuclear Reactors for space propulsion and space power systems. These small engines directly convert the high speed charged particles produced in the thermonuclear reactor into vehicle thrust or vehicle electricity with maximum efficiency. The simplest AB-thermonuclear propulsion offered allows spaceships to reach speeds of 20,000 50,000 km/s (1/6 of light speed) for fuel ratio 0.1 and produces a huge amount of useful elect...

  5. Report on the Personnel Dosimetry at AB Atomenergi during 1962

    International Nuclear Information System (INIS)

    Edvardsson, K.A.; Hagsgaard, S.

    1963-12-01

    This report presents the results of the personnel dosimetry at AB Atomenergi during 1962. No doses exceeding the recommendations of ICRP have been reported. The sum of the reported external total body doses (≥ 100 mrem/quarter) is for the whole of AB Atomenergi during this year 74. 2 manrem corresponding to about 50 mrem/year and person or 1 % of the maximum permissible dose. 32500 gamma films and 6200 neutron films have been evaluated. The total number of urine analyses is 2700 and of whole body measurements 10

  6. Stability of A-B phase boundary in a constriction

    Energy Technology Data Exchange (ETDEWEB)

    Viljas, Janne; Thuneberg, Erkki

    2003-05-01

    We report on a Ginzburg-Landau calculation of the stability of a boundary between A and B phases of superfluid {sup 3}He in a two-dimensional constriction. In the macroscopic limit the stability follows a well-known relation, which depends on the surface tension {sigma}{sub AB} of the A-B boundary. In the narrow-constriction limit the surface tension is not well defined, but the interface is always stable, and a weak link between the A and B phases is obtained.

  7. An ABS control logic based on wheel force measurement

    Science.gov (United States)

    Capra, D.; Galvagno, E.; Ondrak, V.; van Leeuwen, B.; Vigliani, A.

    2012-12-01

    The paper presents an anti-lock braking system (ABS) control logic based on the measurement of the longitudinal forces at the hub bearings. The availability of force information allows to design a logic that does not rely on the estimation of the tyre-road friction coefficient, since it continuously tries to exploit the maximum longitudinal tyre force. The logic is designed by means of computer simulation and then tested on a specific hardware in the loop test bench: the experimental results confirm that measured wheel force can lead to a significant improvement of the ABS performances in terms of stopping distance also in the presence of road with variable friction coefficient.

  8. Use of ab initio quantum chemical methods in battery technology

    Energy Technology Data Exchange (ETDEWEB)

    Deiss, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Ab initio quantum chemistry can nowadays predict physical and chemical properties of molecules and solids. An attempt should be made to use this tool more widely for predicting technologically favourable materials. To demonstrate the use of ab initio quantum chemistry in battery technology, the theoretical energy density (energy per volume of active electrode material) and specific energy (energy per mass of active electrode material) of a rechargeable lithium-ion battery consisting of a graphite electrode and a nickel oxide electrode has been calculated with this method. (author) 1 fig., 1 tab., 7 refs.

  9. Bruksmakt och maktbruk : Robertsfors AB 1897-1968

    OpenAIRE

    Holmström, Per

    1988-01-01

    This thesis studies seven strategic decisions made in the family-owned forestry company Robertsfors AB, in Northern Sweden. During the present century Ro­bertsfors AB has developed from a patriarchally concern controlled into a capi­talistic industrial company. This also meant a radical change in the decision­making process. Two factors were decisive in this process: the managing direc­tor's values, and altered power relationships both within the company and exter­nally in relation to e g sta...

  10. Qualidade fisiológica e teor de lignina no tegumento de sementes de soja convencional e transgênica RR submetidas a diferentes épocas de colheita Physiological quality and lignin content in the coat seeds of conventional and RR transgenic soybean submitted to different harvest periods

    Directory of Open Access Journals (Sweden)

    Cristiane Fortes Gris

    2010-04-01

    Full Text Available Têm-se levantado à hipótese de que cultivares de soja RR possuem teores de lignina superiores aos convencionais, o que proporciona maior resistência a danos mecânicos e maior impermeabilidade do tegumento das sementes. Objetivou-se avaliar a qualidade fisiológica e o teor de lignina no tegumento das sementes de soja convencional e RR colhidas em três épocas, em Lavras-MG. Para tanto, as sementes colhidas nos estádios R7, R8 e após 20 dias de retardamento da colheita (R8+20, foram submetidas aos testes para avaliação da qualidade fisiológica e teor de lignina. As cultivares convencionais e RR avaliadas foram: BRS 133 vs BRS 245 RR, BRS 134 vs BRS 247 RR, Conquista vs Valiosa RR, Celeste vs Baliza RR e Jataí vs Silvânia RR. Foram realizados os testes de peso de mil sementes, germinação, envelhecimento acelerado, condutividade elétrica, dano mecânico, índice de velocidade de emergência, germinação após a imersão das sementes em água e teor de lignina no tegumento de sementes. Com exceção do teor de lignina no tegumento de sementes para o contraste Jataí vs Silvânia RR, não foram observadas diferenças entre os materiais RR e convencional, tendo, neste caso, a cv Silvânia RR apresentado resultados superiores aos da convencional. No entanto, houve diferença de comportamento entre os cultivares quanto à tolerância ao retardamento da colheita. Observou-se redução significativa na porcentagem de germinação e vigor das sementes avaliadas com o retardamento da colheita.One has raised the hypothesis that the RR soybean cultivars posses lignin contents higher than those of the conventional ones. The present work was conducted with the purpose of evaluating the physiological quality and lignin content in the coat of the conventional and RR soybean seeds collected in three times in Lavras-MG. To that end, the seeds collected at stages R7, R8 and after 20 days of collection delay (R8+20 were submitted to the tests for

  11. Ab initio structure determination via powder X-ray diffraction

    Indian Academy of Sciences (India)

    Although the method of structure completion when once the starting model is provided is facile through the Rietveld refinement technique, the structure solution ab initio os still not push-button technology. In this article a survey of the recent development in this area is provided with an illustration of the structure determination ...

  12. Comparative performance of Anigen © FMD NSP Ab ELISA (Korea ...

    African Journals Online (AJOL)

    Comparative performance of Anigen © FMD NSP Ab ELISA (Korea), NSP Priocheck® kit, liquid phase blocking ELISA kits and virus neutralisation tests in the detection of foot and mouth disease virus antibodies in animals sera from Kilifi county, Kenya.

  13. Bicanonical ab Initio Molecular Dynamics for Open Systems.

    Science.gov (United States)

    Frenzel, Johannes; Meyer, Bernd; Marx, Dominik

    2017-08-08

    Performing ab initio molecular dynamics simulations of open systems, where the chemical potential rather than the number of both nuclei and electrons is fixed, still is a challenge. Here, drawing on bicanonical sampling ideas introduced two decades ago by Swope and Andersen [ J. Chem. Phys. 1995 , 102 , 2851 - 2863 ] to calculate chemical potentials of liquids and solids, an ab initio simulation technique is devised, which introduces a fictitious dynamics of two superimposed but otherwise independent periodic systems including full electronic structure, such that either the chemical potential or the average fractional particle number of a specific chemical species can be kept constant. As proof of concept, we demonstrate that solvation free energies can be computed from these bicanonical ab initio simulations upon directly superimposing pure bulk water and the respective aqueous solution being the two limiting systems. The method is useful in many circumstances, for instance for studying heterogeneous catalytic processes taking place on surfaces where the chemical potential of reactants rather than their number is controlled and opens a pathway toward ab initio simulations at constant electrochemical potential.

  14. Cyanogen Azide. Ionization Potentials and Ab Initio SCF MO Calculation

    DEFF Research Database (Denmark)

    Bak, Börge; Jansen, Peter; Stafast, Herbert

    1975-01-01

    The Ne(I) and He(I) photoelectron(PE) spectra of cyanogen azide, NCN3, have been recorded at high resolution. Their interpretation is achieved by comparison with the PE spectrum of HN3 and an ab initio LCGO SCF MO calculation. Deviations from Koopmans' theorem of quite different magnitudes...

  15. Awareness and knowledge of pro-, prebiotics and ab cultures ...

    African Journals Online (AJOL)

    Awareness and knowledge of pro-, prebiotics and ab cultures among yoghurt buyers in four Pretoria suburbs and the factors determining their yoghurt buying decision. ... Their customers were sought after as income may influence functional food purchasing. The results indicated limited respondent awareness and ...

  16. Iron-substituted AB5-type MH electrode

    Indian Academy of Sciences (India)

    substituted AB5-type MH electrode. SUMITA SRIVASTAVAa,∗ and R K UPADHYAYAb. aDepartment of Physics, Government P.G. College, Uttarkashi 249 193, India. bDepartment of Physics, Government P.G. College, Rishikesh 249 201, India.

  17. Move of Purchasing Offices TS – AB* – AT*

    CERN Multimedia

    FI Department

    2008-01-01

    The TS – AB* - AT* Purchasing Offices and the Purchasing Pool have moved to Building 5 – 2nd and *3rd floors. The phone and fax numbers are unchanged. We apologize for any inconvenience caused by the move. Thank you for your understanding. Finance Department – Purchasing Service.

  18. In vitro Antimicrobial Activity of Homonataloin A/B and ...

    African Journals Online (AJOL)

    Homonataloin A/B was found to exhibit good activity against Staphylococcus aureus and all Salmonella spp. tested with MIC value of 25 μg/ml, whilst the activity of homonataloside (MIC = 25 μg/ml) was highest against Vibrio cholerae strains. Among the fungal strains tested, Candida albicans was the most susceptible ...

  19. Quantifying transition voltage spectroscopy of molecular junctions: Ab initio calculations

    DEFF Research Database (Denmark)

    Chen, Jingzhe; Markussen, Troels; Thygesen, Kristian Sommer

    2010-01-01

    Transition voltage spectroscopy (TVS) has recently been introduced as a spectroscopic tool for molecular junctions where it offers the possibility to probe molecular level energies at relatively low bias voltages. In this work we perform extensive ab initio calculations of the nonlinear current...

  20. Projector augmented wave method: ab initio molecular dynamics ...

    Indian Academy of Sciences (India)

    Unknown

    The projector augmented wave method is an all-electron method for efficient ab initio molecular dynamics simulations with full wave functions. .... In that case the muffin–tin approximation is used solely to define the basis set. ..... functions probe the local character of the auxiliary wave function in the atomic region. Examples ...

  1. The Properties of Some Simple Covalent Hydrides: An Ab Initio ...

    African Journals Online (AJOL)

    Some properties of the monomeric binary hydrides of the elements of the first two rows of the periodic table have been determined using ab initio molecular orbital theory. The properties in question are the energetic, structural, electronic, topological and vibrational characteristics. In general, a gradual convergence towards ...

  2. Hydrogen Bond Dynamics in Aqueous Solutions: Ab initio Molecular ...

    Indian Academy of Sciences (India)

    Rate equation for the decay of CHB(t) · Definition of Hydrogen Bonds · Results of Molecular Dynamics · Dynamics of anion-water and water-water hydrogen bonds · Structural relaxation of anion-water & water-water H-bonds · Ab initio Molecular Dynamics : · Slide 14 · Dynamics of hydrogen bonds : CPMD results · Slide 16.

  3. Ab initio calculation of the structural, mechanical and ...

    African Journals Online (AJOL)

    An ab initio plane-wave Pseudopotential calculations using the density functional theory (DFT) implementing the generalised gradient approximation (GGA) to study the structural, elastic constants, phonon dispersion curves, density of state and thermal properties of BeS. Also we calculated the shear modulus, Young's ...

  4. Early stage precipitation in aluminum alloys : An ab initio study

    NARCIS (Netherlands)

    Zhang, X.

    2017-01-01

    Multiscale computational materials science has reached a stage where many complicated phenomena or properties that are of great importance to manufacturing can be predicted or explained. The word “ab initio study” becomes commonplace as the development of density functional theory has enabled the

  5. Further Food for Thought on the "ABS Guide"

    Science.gov (United States)

    Hussain, Simon

    2012-01-01

    This paper replies to points raised by the editors of the "ABS Guide", Huw Morris, Charles Harvey, Aidan Kelly and Michael Rowlinson (2011) "Accounting Education: an international journal", 20(6), pp. 561-573) in response to a paper published in a previous issue of "Accounting Education" (Hussain, S. (2011)…

  6. Computational Experiments with ABS Algorithms for KKT Linear Systems

    Czech Academy of Sciences Publication Activity Database

    Bodon, E.; Del Popolo, A.; Lukšan, Ladislav; Spedicato, E.

    2001-01-01

    Roč. 16, č. 1-4 (2001), s. 85-99 ISSN 1055-6788 R&D Projects: GA ČR GA201/00/0080 Institutional research plan: AV0Z1030915 Keywords : ABS algorithms * KKT systems Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.623, year: 2001

  7. Young Modulus of Crystalline Polyethylene from ab Initio Molecular Dynamics

    NARCIS (Netherlands)

    Hageman, J.C.L.; Meier, Robert J.; Heinemann, M.; Groot, R.A. de

    1997-01-01

    The Young modulus for crystalline polyethylene is calculated using ab initio molecular dynamics based on density functional theory in the local density approximation (DFT-LDA). This modulus, which can be seen as the ultimate value for the Young modulus of polyethylene fibers, is found to be 334 GPa.

  8. Food for Thought on the "ABS Academic Journal Quality Guide"

    Science.gov (United States)

    Hussain, Simon

    2011-01-01

    This paper discusses issues relating to the use of the Association of Business Schools' (ABS) "Academic Journal Quality Guide" within UK business schools. It also looks at several specific issues raised by the Chair of the British Accounting Association/British Accounting and Finance Association regarding the ratings for top…

  9. Ab initio molecular dynamics simulation of laser melting of silicon

    NARCIS (Netherlands)

    Silvestrelli, P.-L.; Alavi, A.; Parrinello, M.; Frenkel, D.

    1996-01-01

    The method of ab initio molecular dynamics, based on finite temperature density functional theory, is used to simulate laser heating of crystal silicon. We have found that a high concentration of excited electrons dramatically weakens the covalent bond. As a result, the system undergoes a melting

  10. Ab initio study of phase equilibria in TiCx

    DEFF Research Database (Denmark)

    Korzhavyi, P.A.; Pourovskii, L.V.; Hugosson, H.W.

    2002-01-01

    The phase diagram for the vacancy-ordered structures in the substoichiometric TiCx (x = 0.5-1.0) has been established from Monte Carlo simulations with the long-range pair and multisite effective interactions obtained from ab initio calculations. Three ordered superstructures of vacancies (Ti2C, ...

  11. Ab initio calculations of mechanical properties: Methods and applications

    Czech Academy of Sciences Publication Activity Database

    Pokluda, J.; Černý, Miroslav; Šob, Mojmír; Umeno, Y.

    2015-01-01

    Roč. 73, AUG (2015), s. 127-158 ISSN 0079-6425 R&D Projects: GA ČR(CZ) GAP108/12/0311 Institutional support: RVO:68081723 Keywords : Ab initio methods * Elastic moduli * Intrinsic hardness * Stability analysis * Theoretical strength * Intrinsic brittleness/ductility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 31.083, year: 2015

  12. Realization of prediction of materials properties by ab initio ...

    Indian Academy of Sciences (India)

    Unknown

    Ab initio treatment is becoming realistic to predict physical, chemical, and even mechanical pro- perties of academically and ... materials under very high pressure in earth by direct method, and prediction of wavelength of emitted light from Na clusters with GW .... observed band gap value for semiconductors. This big. Quasi- ...

  13. Realization of prediction of materials properties by ab initio ...

    Indian Academy of Sciences (India)

    Ab initio treatment is becoming realistic to predict physical, chemical, and even mechanical properties of academically and industrially interesting materials. There is, however, some limitation in size and time of the system up to the order of several hundred atoms and ∼ 1 pico second, even if we use the fastest ...

  14. AB INITIO calculations of magneto-optical effects

    Czech Academy of Sciences Publication Activity Database

    Kuneš, Jan; Oppeneer, P. M.

    2002-01-01

    Roč. 2, - (2002), s. 141-146 ISSN 1346-7948 R&D Projects: GA AV ČR IAA1010214 Institutional research plan: CEZ:AV0Z1010914 Keywords : electronic structure * ab initio calculation * polar magneto-optical Kerr effect * transitiom metal * uranium intermetallics * CrO 2 Subject RIV: BM - Solid Matter Physics ; Magnetism

  15. Kinesin-2 KIF3AB exhibits novel ATPase characteristics.

    Science.gov (United States)

    Albracht, Clayton D; Rank, Katherine C; Obrzut, Steven; Rayment, Ivan; Gilbert, Susan P

    2014-10-03

    KIF3AB is an N-terminal processive kinesin-2 family member best known for its role in intraflagellar transport. There has been significant interest in KIF3AB in defining the key principles that underlie the processivity of KIF3AB in comparison with homodimeric processive kinesins. To define the ATPase mechanism and coordination of KIF3A and KIF3B stepping, a presteady-state kinetic analysis was pursued. For these studies, a truncated murine KIF3AB was generated. The results presented show that microtubule association was fast at 5.7 μm(-1) s(-1), followed by rate-limiting ADP release at 12.8 s(-1). ATP binding at 7.5 μm(-1) s(-1) was followed by an ATP-promoted isomerization at 84 s(-1) to form the intermediate poised for ATP hydrolysis, which then occurred at 33 s(-1). ATP hydrolysis was required for dissociation of the microtubule·KIF3AB complex, which was observed at 22 s(-1). The dissociation step showed an apparent affinity for ATP that was very weak (K½,ATP at 133 μm). Moreover, the linear fit of the initial ATP concentration dependence of the dissociation kinetics revealed an apparent second-order rate constant at 0.09 μm(-1) s(-1), which is inconsistent with fast ATP binding at 7.5 μm(-1) s(-1) and a Kd ,ATP at 6.1 μm. These results suggest that ATP binding per se cannot account for the apparent weak K½,ATP at 133 μm. The steady-state ATPase Km ,ATP, as well as the dissociation kinetics, reveal an unusual property of KIF3AB that is not yet well understood and also suggests that the mechanochemistry of KIF3AB is tuned somewhat differently from homodimeric processive kinesins. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Perspective: Ab initio force field methods derived from quantum mechanics

    Science.gov (United States)

    Xu, Peng; Guidez, Emilie B.; Bertoni, Colleen; Gordon, Mark S.

    2018-03-01

    It is often desirable to accurately and efficiently model the behavior of large molecular systems in the condensed phase (thousands to tens of thousands of atoms) over long time scales (from nanoseconds to milliseconds). In these cases, ab initio methods are difficult due to the increasing computational cost with the number of electrons. A more computationally attractive alternative is to perform the simulations at the atomic level using a parameterized function to model the electronic energy. Many empirical force fields have been developed for this purpose. However, the functions that are used to model interatomic and intermolecular interactions contain many fitted parameters obtained from selected model systems, and such classical force fields cannot properly simulate important electronic effects. Furthermore, while such force fields are computationally affordable, they are not reliable when applied to systems that differ significantly from those used in their parameterization. They also cannot provide the information necessary to analyze the interactions that occur in the system, making the systematic improvement of the functional forms that are used difficult. Ab initio force field methods aim to combine the merits of both types of methods. The ideal ab initio force fields are built on first principles and require no fitted parameters. Ab initio force field methods surveyed in this perspective are based on fragmentation approaches and intermolecular perturbation theory. This perspective summarizes their theoretical foundation, key components in their formulation, and discusses key aspects of these methods such as accuracy and formal computational cost. The ab initio force fields considered here were developed for different targets, and this perspective also aims to provide a balanced presentation of their strengths and shortcomings. Finally, this perspective suggests some future directions for this actively developing area.

  17. Processed CTD and Water Sample Data from Research Vessel Roger Revelle, Expedition RR1214, in the NE Pacific in November 2012 (NCEI Accession 0156228)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Expedition RR1214 by research vessel Roger Revelle was primarily a transit from French Polynesia to the US mainland. However, a small scientific program was...

  18. Interval ridge regression (iRR) as a fast and robust method for quantitative prediction and variable selection applied to edible oil adulteration.

    Science.gov (United States)

    Jović, Ozren; Smrečki, Neven; Popović, Zora

    2016-04-01

    A novel quantitative prediction and variable selection method called interval ridge regression (iRR) is studied in this work. The method is performed on six data sets of FTIR, two data sets of UV-vis and one data set of DSC. The obtained results show that models built with ridge regression on optimal variables selected with iRR significantly outperfom models built with ridge regression on all variables in both calibration (6 out of 9 cases) and validation (2 out of 9 cases). In this study, iRR is also compared with interval partial least squares regression (iPLS). iRR outperfomed iPLS in validation (insignificantly in 6 out of 9 cases and significantly in one out of 9 cases for p0.99). Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Protective mAbs and Cross-Reactive mAbs Raised by Immunization with Engineered Marburg Virus GPs.

    Directory of Open Access Journals (Sweden)

    Marnie L Fusco

    2015-06-01

    Full Text Available The filoviruses, which include the marburg- and ebolaviruses, have caused multiple outbreaks among humans this decade. Antibodies against the filovirus surface glycoprotein (GP have been shown to provide life-saving therapy in nonhuman primates, but such antibodies are generally virus-specific. Many monoclonal antibodies (mAbs have been described against Ebola virus. In contrast, relatively few have been described against Marburg virus. Here we present ten mAbs elicited by immunization of mice using recombinant mucin-deleted GPs from different Marburg virus (MARV strains. Surprisingly, two of the mAbs raised against MARV GP also cross-react with the mucin-deleted GP cores of all tested ebolaviruses (Ebola, Sudan, Bundibugyo, Reston, but these epitopes are masked differently by the mucin-like domains themselves. The most efficacious mAbs in this panel were found to recognize a novel "wing" feature on the GP2 subunit that is unique to Marburg and does not exist in Ebola. Two of these anti-wing antibodies confer 90 and 100% protection, respectively, one hour post-exposure in mice challenged with MARV.

  20. The melt rheological behavior of AB, ABA, BAB, and (AB)n block copolymers with monodisperse aramide segments

    NARCIS (Netherlands)

    Araichimani, A.; Dullaert, Konraad; Gaymans, R.J.

    2009-01-01

    The melt rheological behavior of segmented block copolymers with high melting diamide (A) hard segments (HS) and polyether (B) soft segments was studied. The block copolymers can be classified as B (monoblock), AB (diblock), ABA (triblock, diamide end segment), BAB (triblock, diamide mid-segment)

  1. Ab initio simulation of dislocation cores in metals; Simulation ab initio des coeurs de dislocation dans les metaux

    Energy Technology Data Exchange (ETDEWEB)

    Ventelon, L. [CEA Saclay, Dept. des Materiaux pour le Nucleaire (DEN/DANS/DMN/SRMP), 91 - Gif-sur-Yvette (France)

    2008-07-01

    In the framework of the multi scale simulation of metals and alloys plasticity, the aim of this study is to develop a methodology of ab initio dislocations study and to apply it to the [111] screw dislocation in the bc iron. (A.L.B.)

  2. The crystal structure of the AhRR-ARNT heterodimer reveals the structural basis of the repression of AhR-mediated transcription.

    Science.gov (United States)

    Sakurai, Shunya; Shimizu, Toshiyuki; Ohto, Umeharu

    2017-10-27

    2,3,7,8-Tetrachlorodibenzo- p -dioxin and related compounds are extraordinarily potent environmental toxic pollutants. Most of the 2,3,7,8-tetrachlorodibenzo- p -dioxin toxicities are mediated by aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor belonging to the basic helix-loop-helix (bHLH) Per-ARNT-Sim (PAS) family. Upon ligand binding, AhR forms a heterodimer with AhR nuclear translocator (ARNT) and induces the expression of genes involved in various biological responses. One of the genes induced by AhR encodes AhR repressor (AhRR), which also forms a heterodimer with ARNT and represses the activation of AhR-dependent transcription. The control of AhR activation is critical for managing AhR-mediated diseases, but the mechanisms by which AhRR represses AhR activation remain poorly understood, because of the lack of structural information. Here, we determined the structure of the AhRR-ARNT heterodimer by X-ray crystallography, which revealed an asymmetric intertwined domain organization presenting structural features that are both conserved and distinct among bHLH-PAS family members. The structures of AhRR-ARNT and AhR-ARNT were similar in the bHLH-PAS-A region, whereas the PAS-B of ARNT in the AhRR-ARNT complex exhibited a different domain arrangement in this family reported so far. The structure clearly disclosed that AhRR competitively represses AhR binding to ARNT and target DNA and further suggested the existence of an AhRR-ARNT-specific repression mechanism. This study provides a structural basis for understanding the mechanism by which AhRR represses AhR-mediated gene transcription. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Stability of cyanotoxins, microcystin-LR, microcystin-RR and nodularin in seawater and BG-11 medium of different salinity

    OpenAIRE

    Hanna Mazur; Marcin Pliñski

    2001-01-01

    Microcystins and nodularin are potent hepatotoxins produced by fresh and seawater cyanobacteria. The persistence of three hepatotoxins - microcystin-LR, microcystin-RR and nodularin - was investigated in sterile BG-11 medium of different salinity and in water collected from the Gulf of Gdansk. After 21 days of incubation at 17 ± 1oC and constant illumination of about 40 µmol photon m-2 s-1 the concentration of toxins decreased by about 30-37%. No significant changes in toxin concent...

  4. A review on research activities using the SANS spectrometer in transmission geometry at ET-RR-1 reactor

    International Nuclear Information System (INIS)

    Adib, M.

    1999-01-01

    The phased double rotor facility operating at ET-RR-1 reactor (2MW) was rearranged to operate as SANS spectrometer in transmission geometry. The rotors are suspended in magnetic fields and are spinning up to 16,000 rpm producing bursts of polyenergetic neutrons with wavelengths from 0.2 nm to 6.5 nm and beam divergence of 17' on the sample. The review on research activities using the SANS spectrometer and its applications for powder particle size determination and the long wavelength fluctuation of magnetization of the Fe-Ni alloys are discussed. (author)

  5. Research on the Solid State Fermentation of Jerusalem Artichoke Pomace for Producing R,R-2,3-Butanediol by Paenibacillus polymyxa ZJ-9.

    Science.gov (United States)

    Cao, Can; Zhang, Li; Gao, Jian; Xu, Hong; Xue, Feng; Huang, Weiwei; Li, Yan

    2017-06-01

    R,R-2,3-butanediol (R,R-2,3-BD) was produced by Paenibacillus polymyxa ZJ-9, which was capable of utilizing inulin without previous hydrolysis. The Jerusalem artichoke pomace (JAP) derived from the conversion of Jerusalem artichoke powder into inulin extract, which was usually used for biorefinery by submerged fermentation (SMF), was utilized in solid state fermentation (SSF) to produce R,R-2,3-BD. In this study, the fermentation parameters of SSF were optimized and determined in flasks. A novel bioreactor was designed and assembled for the laboratory scale-up of SSF, with a maximum yield of R,R-2,3-BD (67.90 g/kg (JAP)). This result is a 36.3% improvement compared with the flasks. Based on the same bath of Jerusalem artichoke powder, the total output of R,R-2,3-BD increased by 38.8% for the SSF of JAP combined with the SMF of inulin extraction. Overall, the utilization of JAP for R,R-2,3-BD production was beneficial to the comprehensive utilization of Jerusalem artichoke tuber.

  6. Development of Anti-lock Braking System (ABS) for Vehicles Braking

    OpenAIRE

    Minh Vu Trieu; Oamen Godwin; Vassiljeva Kristina; Teder Leo

    2016-01-01

    This paper develops a real laboratory of anti-lock braking system (ABS) for vehicle and conducts real experiments to verify the ability of this ABS to prevent the vehicle wheel from being locked while braking. Two controllers of PID and fuzzy logic are tested for analysis and comparison. This ABS laboratory is designed for bachelor and master students to simulate and analyze performances of ABS with different control techniques on various roads and load conditions. Thi...

  7. FREQUENCY ANALYSIS OF PHOTOGRAPHIC OBSERVATIONS OF PULSATING STARS

    OpenAIRE

    Bezdenezhnyi, V. P.

    2017-01-01

    The Fourier analysis are performed for photoelectric and photographic B-observations (Goranskij and Shugarov, 1979) of RR Lyrae star RW Ari. Besides the main frequency f0 and four its first harmonics two more frequencies are found: f1 =f0 /3 and f2 =0.711f0 c/d. It permits to identify frequencies: f0 as fs, introduced by us earlier (Bezdenezhnyi, 1997b) for RR Lyrae star T Sex, and f2 - as f1H. Such analysis of photographic author's observations of RR Lyrae star BK Dra is performed too. It is...

  8. Degradation efficiency and mechanism of azo dye RR2 by a novel ozone aerated internal micro-electrolysis filter.

    Science.gov (United States)

    Zhang, Xian-Bing; Dong, Wen-Yi; Sun, Fei-Yun; Yang, Wei; Dong, Jiao

    2014-07-15

    A newly designed ozone aerated internal micro-electrolysis filter (OIEF) was developed to investigate its degradation efficiencies and correlated reaction mechanisms of RR2 dye. Complete decolorization and 82% TOC removal efficiency were stably achieved in OIEF process. Based on the comprehensive experimental results, an empirical equation was proposed to illustrate the effects of initial dye concentration and ozone dosage rate on color removal. The results indicated that OIEF process could be operated at wide pH range without significant treatment efficiencies change, while the optimum pH for RR2 dye degradation was 9.0. There were 15, 8 and 6 kinds of identified intermediates during ozonation, IE and OIEF treatment processes, respectively. Less identified intermediates and their lower concentrations in OIEF may attribute to its rather excellent mineralization performance. It was found that ozonation, Fe(2+)/Fe(3+) catalyzed ozonation, the redox reactions of electro-reduction and electro-oxidation are the most important mechanisms in OIEF process. The catalytic effect of Fe(2+)/Fe(3+) would induce mutual conversion between dissolved Fe(2+) and Fe(3+), and then decrease the dissolution rate of ZVI. The excellent treatment performance proved that the OIEF process is one promising technology applied for reactive azo dyes and other refractory wastewater treatment. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Optimization of the Parameters Affecting the Fenton Process for Decolorization of Reactive Red 198 (RR-198 from the Aqueous Phase

    Directory of Open Access Journals (Sweden)

    Mansooreh Dehghani

    2015-10-01

    Full Text Available Background: Recently, there has been a great concern about the consumption of dyes because of their toxicity, mutagenicity, carcinogenicity, and persistence in the aquatic environment. Reactive dyes are widely used in textile industry. Advanced oxidation processes are one of the cost-effective methods for the removal of these dyes. The main aims of this study were determining the feasibility of using Fenton process in removing Reactive Red 198 (RR-198 dye from aqueous solution and determining the optimal conditions. Methods: This is a cross-sectional study conducted at a laboratory scale. A total of 69 samples were considered and the effect of pH, Fe (II concentration, H2O2 concentration, initial dye concentration and reaction time were investigated. Results: According to the results, a maximum removal efficiency of 92% was obtained at pH of 3 and the reaction time of 90 min; also, the concentration of Fe (II, H2O2, initial dye concentration were 100 mg/L, 50 mg/L, and 100 mg/L, respectively. The results revealed that by increasing the concentration of Fe (II, H2O2 and initial dye, the removal efficiency was increased. Conclusions: The results showed that Fenton process could be used as a cost-effective method for removing RR-198 dye from textile wastewater efficiently.

  10. Augmented wave ab initio EFG calculations: some methodological warnings

    International Nuclear Information System (INIS)

    Errico, Leonardo A.; Renteria, Mario; Petrilli, Helena M.

    2007-01-01

    We discuss some accuracy aspects inherent to ab initio electronic structure calculations in the understanding of nuclear quadrupole interactions. We use the projector augmented wave method to study the electric-field gradient (EFG) at both Sn and O sites in the prototype cases SnO and SnO 2 . The term ab initio is used in the standard context of the also called first principles methods in the framework of the Density Functional Theory. As the main contributions of EFG calculations to problems in condensed matter physics are related to structural characterizations on the atomic scale, we discuss the 'state of the art' on theoretical EFG calculations and make a brief critical review on the subject, calling attention to some fundamental theoretical aspects

  11. Augmented wave ab initio EFG calculations: some methodological warnings

    Energy Technology Data Exchange (ETDEWEB)

    Errico, Leonardo A. [Departamento de Fisica-IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CC67 (1900) La Plata (Argentina); Renteria, Mario [Departamento de Fisica-IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CC67 (1900) La Plata (Argentina); Petrilli, Helena M. [Instituto de Fisica-DFMT, Universidade de Sao Paulo, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil)]. E-mail: hmpetril@macbeth.if.usp.br

    2007-02-01

    We discuss some accuracy aspects inherent to ab initio electronic structure calculations in the understanding of nuclear quadrupole interactions. We use the projector augmented wave method to study the electric-field gradient (EFG) at both Sn and O sites in the prototype cases SnO and SnO{sub 2}. The term ab initio is used in the standard context of the also called first principles methods in the framework of the Density Functional Theory. As the main contributions of EFG calculations to problems in condensed matter physics are related to structural characterizations on the atomic scale, we discuss the 'state of the art' on theoretical EFG calculations and make a brief critical review on the subject, calling attention to some fundamental theoretical aspects.

  12. Soliton solutions for ABS lattice equations: I. Cauchy matrix approach

    Science.gov (United States)

    Nijhoff, Frank; Atkinson, James; Hietarinta, Jarmo

    2009-10-01

    In recent years there have been new insights into the integrability of quadrilateral lattice equations, i.e. partial difference equations which are the natural discrete analogues of integrable partial differential equations in 1+1 dimensions. In the scalar (i.e. single-field) case, there now exist classification results by Adler, Bobenko and Suris (ABS) leading to some new examples in addition to the lattice equations 'of KdV type' that were known since the late 1970s and early 1980s. In this paper, we review the construction of soliton solutions for the KdV-type lattice equations and use those results to construct N-soliton solutions for all lattice equations in the ABS list except for the elliptic case of Q4, which is left to a separate treatment.

  13. Chemical and Electrochemical Metallic Covering of ABS polymers

    Directory of Open Access Journals (Sweden)

    Florentina Cziple

    2009-10-01

    Full Text Available The aim of this paper is the deposition of metallic layers on the surface of ABS plastic material, by means of two consecutive procedures, namely: the first is represented by the conductibility through chemical or electro-chemical metallic covering of the polymeric support and the second procedure is the electrodeposition of the metal through galvanization. The chemical mehtod consists in the submission of ABS polymers to some conductibility operations of the plastic material surface through chemical copper plating (chemical roughing, degreasing with ultra-sounds, chemical sensitivation, activation and proper conductibility of the material surface. The electrochemical deposition of nickel was made on the plastic material activated in the mixture solution of graphite with potassium carbonate.

  14. Polariton Bose condensate in an open system: Ab initio approach

    Science.gov (United States)

    Elistratov, A. A.; Lozovik, Yu. E.

    2018-01-01

    In the framework of path-integral formalism and Keldysh technique for a nonequilibrium system we explore the kinetics of the polariton condensate in a quantum well embedded in an optical microcavity. We take into account pumping and leakage of excitons and photons. We make an ab initio derivation of the equations governing the dynamics of the condensates and reservoirs and show that the real open polariton system has a non-Markovian character at times comparable to the Rabi oscillation period.

  15. Report on the Personnel Dosimetry at AB Atomenergi during 1967

    International Nuclear Information System (INIS)

    Carlsson, J.; Wahlberg, T.

    1968-12-01

    This report presents the results of personnel dosimetry at AB Atomenergi during 1967. The external total body gamma dose for all employees (quarterly doses ≤ 100 mrem are not reported) corresponds to 140 manrem. The highest external total body gamma dose during 1967 to one person was 5700 mrem. 24700 gamma films and 3900 neutron films were evaluated. 1988 urine analyses and 989 measurements of body activity were made

  16. Personality at Work: A Study of Type A-B

    Directory of Open Access Journals (Sweden)

    Amber Raza

    2007-10-01

    Full Text Available The objective of this study was to measure the impact of stressors on personality types in Call Centers. Based on literature survey five potential workplace stressors were identified, namely (1 Task Demands, (2 Role Demands, (3 Interpersonal Demands, (4 Organizational Structure and (5 Organizational Leadership. Based on the literature survey, a relationship model was developed that was inclusive of the above stressors, and three personality types, which were Type A, Type AB and Type B.The sample size for the study was 100. The subjects were supervisors and agents drawn non-randomly from various Call Centers of Karachi. All the subjects completed a questionnaire comprised of 27 questions based on occupational stress index (Srivasta and Singh 1981 and AB Personality Continuum (National Institute of Safety and Health 1975. The three personality types A, B & AB all go through stress, however it is the Type A, which thrives on stress. The sources of stress measured in the study were Task Demand, Role Demand, Interpersonal Demands, Organizational Structure and Organizational Leadership.The stressor that most contributed to the Personality type A’s stress in the study was Interpersonal Demand (0.38, which is justified by the literature review as Personality type A are not team players and prefer to work alone.Whereas Personality type B was stressed because of Role Demand (0.38 which is also proved by the literature review as personality type B are laid back and do not take there roles seriously. Hence it can be concluded that it type A tends to cope well with stress as compared to type AB and type B. The performance of the respondents can be made better if the supervisors are aware of the personality types and thereby motivate them according.

  17. Probing the A-B interface of superfluid helium-3

    Science.gov (United States)

    Haley, Richard

    2015-03-01

    At temperatures around 1 mK helium-3 forms a BCS spin triplet condensate. The order parameter is sufficiently complex that more than one superfluid phase exists, each exhibiting a different broken symmetry, and there is a model first order transition between the two most stable phases, labeled A and B. The Lancaster Ultra-Low Temperature Group has developed techniques to probe the properties of the A-B interface in the deep sub-mK regime where the superfluid is in the pure condensate limit. Shaped and controllable magnetic fields are used to induce the transition, and to stabilize and move the A-B phase boundary inside the experimental volume. The latent heat of the transition has been measured, and the nucleation behavior shown to be incompatible with conventional thermodynamic models. Since superfluid helium-3 is inherently pure, and the order parameter transforms continuously across the A-B interface, it is the most coherent two-dimensional structure to which we have experimental access. It has been proposed that this 2D surface in the surrounding 3D bulk volume is a good analog of a cosmological brane separating two distinct quantum vacuum states; experiments that simulate brane annihilation and the creation of topological defects have been carried out at Lancaster. Other investigations have included measurements of the surface tension and wetting behavior of the interface. During these studies it was discovered that a large, unpredicted frictional force was acting on the interface even though it is moving through a pure superfluid. Recent breakthrough work on the dynamics of the A-B interface has finally solved this puzzle. Current experiments include a setup where the interface region is probed directly using quartz tuning fork resonators that couple to the local density of broken Cooper pair quasiparticle excitations and thus give insight into the order parameter energy gap structure as A transforms to B.

  18. Ab initio nuclear structure - the large sparse matrix eigenvalue problem

    International Nuclear Information System (INIS)

    Vary, James P; Maris, Pieter; Ng, Esmond; Yang, Chao; Sosonkina, Masha

    2009-01-01

    The structure and reactions of light nuclei represent fundamental and formidable challenges for microscopic theory based on realistic strong interaction potentials. Several ab initio methods have now emerged that provide nearly exact solutions for some nuclear properties. The ab initio no core shell model (NCSM) and the no core full configuration (NCFC) method, frame this quantum many-particle problem as a large sparse matrix eigenvalue problem where one evaluates the Hamiltonian matrix in a basis space consisting of many-fermion Slater determinants and then solves for a set of the lowest eigenvalues and their associated eigenvectors. The resulting eigenvectors are employed to evaluate a set of experimental quantities to test the underlying potential. For fundamental problems of interest, the matrix dimension often exceeds 10 10 and the number of nonzero matrix elements may saturate available storage on present-day leadership class facilities. We survey recent results and advances in solving this large sparse matrix eigenvalue problem. We also outline the challenges that lie ahead for achieving further breakthroughs in fundamental nuclear theory using these ab initio approaches.

  19. Ab Initio Nuclear Structure and Reaction Calculations for Rare Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Draayer, Jerry P. [Louisiana State Univ., Baton Rouge, LA (United States)

    2014-09-28

    We have developed a novel ab initio symmetry-adapted no-core shell model (SA-NCSM), which has opened the intermediate-mass region for ab initio investigations, thereby providing an opportunity for first-principle symmetry-guided applications to nuclear structure and reactions for nuclear isotopes from the lightest p-shell systems to intermediate-mass nuclei. This includes short-lived proton-rich nuclei on the path of X-ray burst nucleosynthesis and rare neutron-rich isotopes to be produced by the Facility for Rare Isotope Beams (FRIB). We have provided ab initio descriptions of high accuracy for low-lying (including collectivity-driven) states of isotopes of Li, He, Be, C, O, Ne, Mg, Al, and Si, and studied related strong- and weak-interaction driven reactions that are important, in astrophysics, for further understanding stellar evolution, X-ray bursts and triggering of s, p, and rp processes, and in applied physics, for electron and neutrino-nucleus scattering experiments as well as for fusion ignition at the National Ignition Facility (NIF).

  20. Monte Carlo simulation of AB-copolymers with saturating bonds

    CERN Document Server

    Chertovich, A V; Khokhlov, A R; Bohr, J

    2003-01-01

    Structural transitions in a single AB-copolymer chain where saturating bonds can be formed between A-and B-units are studied by means of Monte Carlo computer simulations using the bond fluctuation model. Three transitions are found, coil-globule, coil-hairpin and globule-hairpin, depending on the nature of a particular AB-sequence: statistical random sequence, diblock sequence and 'random-complementary' sequence (one-half of such an AB-sequence is random with Bernoulli statistics while the other half is complementary to the first one). The properties of random-complementary sequences are closer to those of diblock sequences than to the properties of random sequences. The model (although quite rough) is expected to represent some basic features of real RNA molecules, i.e. the formation of secondary structure of RNA due to hydrogen bonding of corresponding bases and stacking interactions of the base pairs in helixes. We introduce the notation of RNA-like copolymers and discuss in what sense the sequences studie...

  1. Pressure tracking control of vehicle ABS using piezo valve modulator

    Science.gov (United States)

    Jeon, Juncheol; Choi, Seung-Bok

    2011-03-01

    This paper presents a wheel slip control for the ABS(anti-lock brake system) of a passenger vehicle using a controllable piezo valve modulator. The ABS is designed to optimize for braking effectiveness and good steerability. As a first step, the principal design parameters of the piezo valve and pressure modulator are appropriately determined by considering the braking pressure variation during the ABS operation. The proposed piezo valve consists of a flapper, pneumatic circuit and a piezostack actuator. In order to get wide control range of the pressure, the pressure modulator is desired. The modulator consists of a dual-type cylinder filled with different substances (fluid and gas) and a piston rod moving vertical axis to transmit the force. Subsequently, a quarter car wheel slip model is formulated and integrated with the governing equation of the piezo valve modulator. A sliding mode controller to achieve the desired slip rate is then designed and implemented. Braking control performances such as brake pressure and slip rate are evaluated via computer simulations.

  2. Towards hydrogen metallization: an Ab initio approach; Vers la metallisation de l`hydrogene: approche AB initio

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, St

    1998-12-31

    The quest for metallic hydrogen is a major goal for both theoretical and experimental condensed matter physics. Hydrogen and deuterium have been compressed up to 200 GPa in diamond anvil cells, without any clear evidence for a metallic behaviour. Loubeyere has recently suggested that hydrogen could metallize, at pressures within experimental range, in a new Van der Waals compound: Ar(H{sub 2}){sub 2} which is characterized at ambient pressure by an open and anisotropic sublattice of hydrogen molecules, stabilized by an argon skeleton. This thesis deals with a detailed ab initio investigation, by Car-Parrinello molecular dynamics methods, of the evolution under pressure of this compound. In a last chapter, we go to much higher pressures and temperatures, in order to compare orbital and orbital free ab initio methods for the dense hydrogen plasma. (author) 109 refs.

  3. Hospital antibiotic management in Poland--results of the ABS maturity survey of the ABS International group.

    Science.gov (United States)

    Olczak-Pienkowska, Anna; Mazinska, Beata; Ozorowski, Tomasz; Hryniewicz, Waleria

    2008-01-01

    The increasing incidence of antibiotic resistance is a serious worldwide problem, as underlined by European Union documents. The project ABS International has been appointed to identify strengths and weaknesses of hospitals with regard to issues related to antibiotic policy. The questionnaire "ABS hospital mature" was developed within the study to analyze the ABS-related maturities in nine member states of the EU. Several fields of antibiotic strategy in hospitals were explored. In Poland the questionnaire was sent to over 100 hospitals and the responses were delivered to the National Medicines Institute (the project representative in Poland) via the internet. The hospitals involved represented three referral levels according to services provided. Within the hospital, the questionnaire was filled out by a microbiologist or an infectious disease specialist. Within the examined fields there were no serious differences between the referral levels. Microbial diagnostics obtained the highest score, whereas "antibiotic-related relationships" and "antibiotic-related personnel development" ranked lowest. Maturity in the field of the antibiotic strategy differs among Polish hospitals. The highest score in the general assessment was assigned to hospitals at secondary referral level. Knowledge on issues of antibiotic resistance and microbiological services and procedures obtained the highest score but its implementation was not sufficient. Results suggest a need to increase the number of specialists in antibiotic usage and policy, and to improve collaboration within and between hospitals.

  4. RPL18aB helps maintain suspensor identity during early embryogenesis.

    Science.gov (United States)

    Xie, Fei; Yan, Hailong; Sun, Yang; Wang, Yameng; Chen, Hong; Mao, Wanying; Zhang, Liyao; Sun, Mengxiang; Peng, Xiongbo

    2018-04-01

    During embryogenesis, plants are thought to use a mechanism that allows the suspensor to maintain its identity. Here, we reported that RPL18aB is involved in this mechanism in Arabidopsis thaliana. The suspensor cells proliferated in rpl18aB and formed a multicellular structure rather than undergo programmed cell death, as in wild type. Suspensors of rpl18aB expressed the embryo proper marker, DRN::GFP, but not the suspensor marker, WOX8::GFP. In addition, auxin accumulated throughout the suspensors of rpl18aB proembryos. Suspensor-specific expression of RPL18aB could rescue the cell proliferation defects in rpl18aB suspensors. These findings supported a role for RPL18aB in maintaining suspensor identity. © 2017 Institute of Botany, Chinese Academy of Sciences.

  5. Acute and residual effects in adolescent rats resulting from exposure to the novel synthetic cannabinoids AB-PINACA and AB-FUBINACA.

    Science.gov (United States)

    Kevin, Richard C; Wood, Katie E; Stuart, Jordyn; Mitchell, Andrew J; Moir, Michael; Banister, Samuel D; Kassiou, Michael; McGregor, Iain S

    2017-06-01

    Synthetic cannabinoids (SCs) have rapidly proliferated as recreational drugs, and may present a substantial health risk to vulnerable populations. However, information on possible effects of long-term use is sparse. This study compared acute and residual effects of the popular indazole carboxamide SC compounds AB-PINACA and AB-FUBINACA in adolescent rats with ∆ 9 -tetrahydrocannabinol (THC) and control treatments. Albino Wistar rats were injected (i.p.) with AB-PINACA or AB-FUBINACA every second day (beginning post-natal day (PND) 31), first at a low dose (0.2 mg/kg on 6 days) followed by a higher dose (1 mg/kg on a further 6 days). THC-treated rats received equivalent doses of 6 × 1 mg/kg and 6 × 5 mg/kg. During drug treatment, THC, AB-PINACA, and AB-FUBINACA decreased locomotor activity at high and low doses, increased anxiety-like behaviours and audible vocalisations, and reduced weight gain. Two weeks after dosing was completed, all cannabinoid pre-treated rats exhibited object recognition memory deficits. These were notably more severe in rats pre-treated with AB-FUBINACA. However, social interaction was reduced in the THC pre-treated group only. Six weeks post-dosing, plasma levels of cytokines interleukin (IL)-1α and IL-12 were reduced by AB-FUBINACA pre-treatment, while cerebellar endocannabinoids were reduced by THC and AB-PINACA pre-treatment. The acute effects of AB-PINACA and AB-FUBINACA were broadly similar to those of THC, suggesting that acute SC toxicity in humans may be modulated by dose factors, including inadvertent overdose and product contamination. However, some lasting residual effects of these different cannabinoid receptor agonists were subtly different, hinting at recruitment of different mechanisms of neuroadaptation.

  6. Influence of HBcAb positivity in the organ donor in heart transplantation.

    Science.gov (United States)

    Chamorro, C; Aparicio, M

    2012-11-01

    There is a significant risk of hepatitis B transmission from HBsAg (-), HBcAb (+) donors in liver transplantation, but there is little information about hepatitis B transmission from HBcAb heart donors. The present study examines the influence of HBcAb presence in relation to heart donor acceptance and offers an update of the published studies. Survey and medical database update from 1994 to October 2011. Spanish heart transplantation teams. Not applicable. Acceptance of heart transplant from an HBcAb (+) organ donor. Twelve out of 15 surveyed teams were seen to vaccinate against HBV, and two quantify HBsAb titers. Seven teams specifically request donor HBcAb status. If the latter proves positive, two do not accept transplantation, two accept if the donor is also HBsAb (+), one selects the receptor under emergency conditions, and three use drug prophylaxis isolatedly or complementary to the above. Only one case of hepatitis B has been reported in a HBcAb (-) and HBsAb (-) receptor that did not receive prophylactic measures. There have been reports of seroconversion of the HBcAb and HBsAb markers, though with an uncertain etiology. HBcAb seropositivity influences acceptance of a heart donor, but agreement is lacking. There is limited information on receptor evolution. To date there has been one reported case of hepatitis B after heart transplant. Although rare, an HBcAb (+) donor can harbor occult HBV infection. The risk of infection can be prevented with appropriate HBsAb titers following vaccination or by pharmacological measures. Copyright © 2011 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  7. On new bulk singularity structures, RR couplings in the asymmetric picture and their all order α{sup '} corrections

    Energy Technology Data Exchange (ETDEWEB)

    Hatefi, Ehsan [Queen Mary University of London, Centre for Research in String Theory, School of Physics and Astronomy, London (United Kingdom); TU Wien, Institute for Theoretical Physics, Vienna (Austria)

    2017-08-15

    We have analyzed in detail four and five point functions of the string theory amplitudes, including a closed string Ramond-Ramond (RR) in an asymmetric picture and either two or three transverse scalar fields in both IIA and IIB. The complete forms of these S-matrices are derived and these asymmetric S-matrices are also compared with their own symmetric results. This leads us to explore two different kinds of bulk singularity structures as well as various new couplings in the asymmetric picture of the amplitude in type II string theory. All order α{sup '} higher derivative corrections to these new couplings have been discovered as well. Several remarks for these two new bulk singularity structures and for contact interactions of the S-matrix have also been made. (orig.)

  8. NMR Studies on Key Residues That Affect Phosphorylation and Dephosphorylation Processes of Bacterial Response Regulator RR468

    Directory of Open Access Journals (Sweden)

    WANG Dan

    2017-12-01

    Full Text Available Response regulator proteins are important components of the two-component signal transduction systems, and essential in transferring the signal delivered from the sensor histidine kinase and eliciting an adaptive response. Phosphorylation and dephosphorylation of the response regulator proteins determine the direction of the signal transduction process. The phosphorylation and dephosphorylation sites of the response regulator proteins play an important role in exerting their function. Here we studied some key residues of response regulator RR468 from Thermotoga maritima. Site-directed mutagenesis experiments were performed to the key sites M55 and K85, which are located in loop b3-a3 and loop b4-a4, respectively. The structure and dynamics feature of the two mutants were investigated with liquid nuclear magnetic resonance (NMR spectroscopy. The results of functional experiments demonstrated that the two residues could affect the phosphorylation and dephosphorylation processes.

  9. Stability of cyanotoxins, microcystin-LR, microcystin-RR and nodularin in seawater and BG-11 medium of different salinity

    Directory of Open Access Journals (Sweden)

    Hanna Mazur

    2001-09-01

    Full Text Available Microcystins and nodularin are potent hepatotoxins produced by fresh and seawater cyanobacteria. The persistence of three hepatotoxins - microcystin-LR, microcystin-RR and nodularin - was investigated in sterile BG-11 medium of different salinity and in water collected from the Gulf of Gdansk. After 21 days of incubation at 17 ± 1oC and constant illumination of about 40 µmol photon m-2 s-1 the concentration of toxins decreased by about 30-37%. No significant changes in toxin concentration in the BG-11 media of different salinity were observed. When toxins were incubated in non-sterile seawater, their concentrations decreased markedly. It is likely that some strains of bacteria are responsible for the breakdown of the toxins. Nodularin turned out to be more resistant to biodegradation than the two microcystins. The influence of certain components of cyanobacteria cells on the accelerated rate of toxin degradation was also considered.

  10. On new bulk singularity structures, RR couplings in the asymmetric picture and their all order α ' corrections

    Science.gov (United States)

    Hatefi, Ehsan

    2017-08-01

    We have analyzed in detail four and five point functions of the string theory amplitudes, including a closed string Ramond-Ramond (RR) in an asymmetric picture and either two or three transverse scalar fields in both IIA and IIB. The complete forms of these S-matrices are derived and these asymmetric S-matrices are also compared with their own symmetric results. This leads us to explore two different kinds of bulk singularity structures as well as various new couplings in the asymmetric picture of the amplitude in type II string theory. All order α ' higher derivative corrections to these new couplings have been discovered as well. Several remarks for these two new bulk singularity structures and for contact interactions of the S-matrix have also been made.

  11. Vigor da cultivar BMX Potência RR de soja durante o beneficiamento e períodos de armazenamento

    Directory of Open Access Journals (Sweden)

    Adrieli N. K. Juvino

    2014-08-01

    Full Text Available Objetivou-se, com este trabalho, avaliar o vigor das sementes de soja durante as etapas do beneficiamento e ao longo do armazenamento. O experimento foi desenvolvido no Instituto Federal Goiano, Câmpus Rio Verde, e na empresa Sementes Goiás. Utilizou-se o delineamento inteiramente casualizado, segundo o esquema fatorial triplo 6 x 2 x 4 (seis etapas do beneficiamento, duas condições de armazenamento e quatro tempos de armazenamento com três repetições. Foram utilizadas sementes de soja Glycine max (L. Merrill, cultivar BMX Potência RR. As sementes foram avaliadas ao longo do armazenamento (0, 3, 6 e 9 meses quanto ao teor de água, teste de tetrazólio e emergência em areia. Os dados foram analisados por meio de análise de variância e regressão adotando-se o nível de 0,05 de significância. Concluiu-se que o beneficiamento das sementes de soja não afetou a qualidade fisiológica das sementes e a cultivar BMX Potência RR apresentou qualidade fisiológica superior pelo teste tetrazólio (acima de 80% apesar do vigor, germinação e emergência se apresentarem altos durante nove meses de armazenamento e o comprimento de raiz e de plantas jovens normais foi influenciado negativamente pelo tempo. Em câmara climatizada as sementes apresentam maior viabilidade dependendo do teor de água do produto.

  12. HHV-6A/B Integration and the Pathogenesis Associated with the Reactivation of Chromosomally Integrated HHV-6A/B.

    Science.gov (United States)

    Collin, Vanessa; Flamand, Louis

    2017-06-26

    Unlike other human herpesviruses, human herpesvirus 6A and 6B (HHV-6A/B) infection can lead to integration of the viral genome in human chromosomes. When integration occurs in germinal cells, the integrated HHV-6A/B genome can be transmitted to 50% of descendants. Such individuals, carrying one copy of the HHV-6A/B genome in every cell, are referred to as having inherited chromosomally-integrated HHV-6A/B (iciHHV-6) and represent approximately 1% of the world's population. Interestingly, HHV-6A/B integrate their genomes in a specific region of the chromosomes known as telomeres. Telomeres are located at chromosomes' ends and play essential roles in chromosomal stability and the long-term proliferative potential of cells. Considering that the integrated HHV-6A/B genome is mostly intact without any gross rearrangements or deletions, integration is likely used for viral maintenance into host cells. Knowing the roles played by telomeres in cellular homeostasis, viral integration in such structure is not likely to be without consequences. At present, the mechanisms and factors involved in HHV-6A/B integration remain poorly defined. In this review, we detail the potential biological and medical impacts of HHV-6A/B integration as well as the possible chromosomal integration and viral excision processes.

  13. Ab initio simulations for material properties inside Jupiter

    Science.gov (United States)

    French, Martin; Becker, Andreas; Lorenzen, Winfried; Nettelmann, Nadine; Bethkenhagen, Mandy; Wicht, Johannes; Redmer, Ronald

    2013-07-01

    The behavior of warm dense matter is of paramount importance for interior and dynamo models for solar and extrasolar giant planets. For instance, nonmetal-to-metal transitions (e.g. metallization in hydrogen), demixing phenomena (in H-He or C-N-O-H mixtures), and new exotic phases (e.g. with proton conduction in water and ammonia) may occur at high pressures and elevated temperatures. These effects have to be taken into account consistently in corresponding planetary models. Therefore, we apply ab initio molecular dynamics simulations based on finite-temperature density functional theory to calculate thermophysical properties of warm dense matter. In particular we determine the equation of state (thermal and caloric), material (sound velocity, specific heat) and transport properties (electrical and thermal conductivity, viscosity, diffusion coefficient) along the adiabat of Jupiter, i.e. from ambient conditions up to the multi-megabar range [1,2]. This ab initio data set can be used as input in future interior (structure) and dynamo models (magnetic fields, flow dynamics) for this planet. Similar data sets can also be compiled for interior conditions of other solar giant planets so that important problems such as the size of planetary cores necessary for the accretion of gaseous (H/He) or icy (C-N-O hydrides) envelopes, the origin, location and stability of layer boundaries, or the source of an excess (e.g. Saturn) or deficit luminosity (e.g. Uranus) can be studied. The increasing sample of extrasolar planets poses new questions that can be addressed based on such ab initio data sets, e.g. to explain the wide range of radii for planets with similar mass. [1] N. Nettelmann, A. Becker, B. Holst, R. Redmer, Astrophys. J. 750, 52 (2012). [2] M. French, A. Becker, W. Lorenzen, N. Nettelmann, M. Bethkenhagen, J. Wicht, R. Redmer, Astrophys. J. Suppl. Ser. 202, 5 (2012).

  14. Ab-initio theory of scanning tunneling microscopy

    Science.gov (United States)

    di Ventra, M.; Pantelides, S. T.

    1998-03-01

    An ab-initio theory of the Scanning Tunneling Microscope (STM) has been developed by treating the sample and the tip as a single system. The theory combines density functional theory with the Kubo-Greenwood linear-response formalism for the conductivity( See, e.g., N.F. Mott in Conduction in Non-Crystalline Materials), (Oxford University Press, Oxford, 1987).. The current is computed by taking into account the atomic relaxations that occur on both the surface and the tip due to their mutal interactions. Illustrative examples will be presented for the case of a clean Al(110) surface and the same surface with a vacancy.

  15. Pseudopotential for ab initio calculations of uranium compounds

    Science.gov (United States)

    Smirnov, G. S.; Pisarev, V. V.; Stegailov, V. V.

    2018-01-01

    The density functional theory (DFT) is a research tool of the highest importance for electronic structure calculations. It is often the only affordable method for ab initio calculations of complex materials. The pseudopotential approach allows reducing the total number of electrons in the model that speeds up calculations. However, there is a lack of pseudopotentials for heavy elements suitable for condensed matter DFT models. In this work, we present a pseudopotential for uranium developed in the Goedecker–Teter–Hutter form. Its accuracy is illustrated using several molecular and solid-state calculations.

  16. Ab initio calculation of tensile strength in iron

    Czech Academy of Sciences Publication Activity Database

    Friák, Martin; Šob, Mojmír; Vitek, V.

    2003-01-01

    Roč. 83, 31-34 (2003), s. 3529-3537 ISSN 1478-6435. [Multiscale Materials Modelling: Working Theory for Industry /1./. London, 17.06.2002-20.06.2002] R&D Projects: GA AV ČR IAA1041302; GA ČR GA202/03/1351; GA MŠk OC 523.90 Institutional research plan: CEZ:AV0Z2041904 Keywords : ab initio calculations * electronic structure * theoretical tensile strength Subject RIV: BM - Solid Matter Physics ; Magnetism

  17. Iterative projection algorithms for ab initio phasing in virus crystallography.

    Science.gov (United States)

    Lo, Victor L; Kingston, Richard L; Millane, Rick P

    2016-12-01

    Iterative projection algorithms are proposed as a tool for ab initio phasing in virus crystallography. The good global convergence properties of these algorithms, coupled with the spherical shape and high structural redundancy of icosahedral viruses, allows high resolution phases to be determined with no initial phase information. This approach is demonstrated by determining the electron density of a virus crystal with 5-fold non-crystallographic symmetry, starting with only a spherical shell envelope. The electron density obtained is sufficiently accurate for model building. The results indicate that iterative projection algorithms should be routinely applicable in virus crystallography, without the need for ancillary phase information. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Stretching siloxanes: An ab initio molecular dynamics study

    Science.gov (United States)

    Lupton, E. M.; Nonnenberg, C.; Frank, I.; Achenbach, F.; Weis, J.; Bräuchle, C.

    2005-10-01

    We present an ab initio molecular dynamics study of siloxane elastomers placed under tensile stress for comparison with single molecule AFM experiments. Of particular interest is stress-induced chemical bond breaking in the high force regime, where a description of the molecular electronic structure is essential to determine the rupture mechanism. We predict an ionic mechanism for the bond breaking process with a rupture force of 4.4 nN for an isolated siloxane decamer pulled at a rate of 27.3 m/s and indicate lower values at experimental polymer lengths and pulling rates.

  19. Ab initio modeling of small proteins by iterative TASSER simulations

    Directory of Open Access Journals (Sweden)

    Zhang Yang

    2007-05-01

    Full Text Available Abstract Background Predicting 3-dimensional protein structures from amino-acid sequences is an important unsolved problem in computational structural biology. The problem becomes relatively easier if close homologous proteins have been solved, as high-resolution models can be built by aligning target sequences to the solved homologous structures. However, for sequences without similar folds in the Protein Data Bank (PDB library, the models have to be predicted from scratch. Progress in the ab initio structure modeling is slow. The aim of this study was to extend the TASSER (threading/assembly/refinement method for the ab initio modeling and examine systemically its ability to fold small single-domain proteins. Results We developed I-TASSER by iteratively implementing the TASSER method, which is used in the folding test of three benchmarks of small proteins. First, data on 16 small proteins (α-root mean square deviation (RMSD of 3.8Å, with 6 of them having a Cα-RMSD α-RMSD α-RMSD of the I-TASSER models was 3.9Å, whereas it was 5.9Å using TOUCHSTONE-II software. Finally, 20 non-homologous small proteins (α-RMSD of 3.9Å was obtained for the third benchmark, with seven cases having a Cα-RMSD Conclusion Our simulation results show that I-TASSER can consistently predict the correct folds and sometimes high-resolution models for small single-domain proteins. Compared with other ab initio modeling methods such as ROSETTA and TOUCHSTONE II, the average performance of I-TASSER is either much better or is similar within a lower computational time. These data, together with the significant performance of automated I-TASSER server (the Zhang-Server in the 'free modeling' section of the recent Critical Assessment of Structure Prediction (CASP7 experiment, demonstrate new progresses in automated ab initio model generation. The I-TASSER server is freely available for academic users http://zhang.bioinformatics.ku.edu/I-TASSER.

  20. Hydrogen diffusion in liquid aluminum from ab initio molecular dynamics

    Science.gov (United States)

    Jakse, N.; Pasturel, A.

    2014-05-01

    Ab initio molecular dynamics simulations are used to describe the diffusion of hydrogen in liquid aluminum at different temperatures. Quasi-instantaneous jumps separating periods of localized vibrations around a mean position are found to characterize the hydrogen motion at the microscopic scale. The hydrogen motion is furthermore analyzed using the van Hove function. We highlight a non-Fickian behavior for the hydrogen diffusion due to a large spatial distribution of hydrogen jumps. We show that a generalized continuous time random walk (CTRW) model describes the experimental diffusion coefficients in a satisfactory manner. Finally, the impact of impurities and alloying elements on hydrogen diffusion in aluminum is discussed.

  1. Tailoring magnetoresistance at the atomic level: An ab initio study

    KAUST Repository

    Tao, Kun

    2012-01-05

    The possibility of manipulating the tunneling magnetoresistance (TMR) of antiferromagnetic nanostructures is predicted in the framework of ab initio calculations. By the example of a junction composed of an antiferromagnetic dimer and a spin-polarized scanning tunneling microscopy tip we show that the TMR can be tuned and even reversed in sign by lateral and vertical movements of the tip. Moreover, our finite-bias calculations demonstrate that the magnitude and the sign of the TMR can also be tuned by an external voltage. © 2012 American Physical Society.

  2. Manganês via foliar em soja convencional e transgênica RR: efeitos na qualidade de sementes, atividade enzimática, lignina e produtividade

    OpenAIRE

    Carvalho, Everson Reis

    2013-01-01

    O manganês (Mn) está associado à ativação de enzimas, tais como as relacionadas à síntese de lignina, que pode afetar a qualidade das sementes. Existem relatos de que plantas de soja transgênicas, tolerantes ao glifosato (RR), são menos eficientes do que as convencionais no acúmulo de Mn e que cultivares RR possuem teores de lignina superiores. No entanto, os resultados são ainda discrepantes. Assim, objetivou-se neste trabalho avaliar o efeito da aplicação foliar com Mn em soja, no processo ...

  3. [Evaluation of the principles of distribution of electrocardiographic R-R intervals for elaboration of methods of automated diagnosis of cardiac rhythm disorders].

    Science.gov (United States)

    Tsukerman, B M; Finkel'shteĭn, I E

    1987-07-01

    A statistical analysis of prolonged ECG records has been carried out in patients with various heart rhythm and conductivity disorders. The distribution of absolute R-R duration values and relationships between adjacent intervals have been examined. A two-step algorithm has been constructed that excludes anomalous and "suspicious" intervals from a sample of consecutively recorded R-R intervals, until only the intervals between contractions of veritably sinus origin remain in the sample. The algorithm has been developed into a programme for microcomputer Electronica NC-80. It operates reliably even in cases of complex combined rhythm and conductivity disorders.

  4. Ab initio dynamics of the cytochrome P450 hydroxylation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Elenewski, Justin E.; Hackett, John C, E-mail: jchackett@vcu.edu [Department of Physiology and Biophysics and The Massey Cancer Center, School of Medicine, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23219-1540 (United States)

    2015-02-14

    The iron(IV)-oxo porphyrin π-cation radical known as Compound I is the primary oxidant within the cytochromes P450, allowing these enzymes to affect the substrate hydroxylation. In the course of this reaction, a hydrogen atom is abstracted from the substrate to generate hydroxyiron(IV) porphyrin and a substrate-centered radical. The hydroxy radical then rebounds from the iron to the substrate, yielding the hydroxylated product. While Compound I has succumbed to theoretical and spectroscopic characterization, the associated hydroxyiron species is elusive as a consequence of its very short lifetime, for which there are no quantitative estimates. To ascertain the physical mechanism underlying substrate hydroxylation and probe this timescale, ab initio molecular dynamics simulations and free energy calculations are performed for a model of Compound I catalysis. Semiclassical estimates based on these calculations reveal the hydrogen atom abstraction step to be extremely fast, kinetically comparable to enzymes such as carbonic anhydrase. Using an ensemble of ab initio simulations, the resultant hydroxyiron species is found to have a similarly short lifetime, ranging between 300 fs and 3600 fs, putatively depending on the enzyme active site architecture. The addition of tunneling corrections to these rates suggests a strong contribution from nuclear quantum effects, which should accelerate every step of substrate hydroxylation by an order of magnitude. These observations have strong implications for the detection of individual hydroxylation intermediates during P450 catalysis.

  5. Microhook ab interno trabeculotomy, a novel minimally invasive glaucoma surgery

    Directory of Open Access Journals (Sweden)

    Tanito M

    2017-12-01

    Full Text Available Masaki Tanito Division of Ophthalmology, Matsue Red Cross Hospital, Matsue, Japan Abstract: Trabeculotomy (LOT is performed to reduce the intraocular pressure in patients with glaucoma, both in children and adults. It relieves the resistance to aqueous flow by cleaving the trabecular meshwork and the inner walls of Schlemm’s canal. Microhook ab interno LOT (µLOT, a novel minimally invasive glaucoma surgery, incises trabecular meshwork using small hooks that are inserted through corneal side ports. An initial case series reported that both µLOT alone and combination of µLOT and cataract surgery normalize the intraocular pressure during the early postoperative period in Japanese patients with glaucoma. Microhook can incise the inner wall of Schlemm’s canal without damaging its outer wall easier than the regular straight knife that is used during goniotomy. Advantages of µLOT include: a wider extent of LOT (two-thirds of the circumference, a simpler surgical technique, being less invasiveness to the ocular surface, a shorter surgical time than traditional ab externo LOT, and no requirement for expensive devices. In this paper, the surgical technique of µLOT and tips of the technique are introduced. Keywords: trabecular meshwork, Schlemm’s canal, intraocular pressure, surgical procedure, glaucoma

  6. Finite Elements in Ab Initio Electronic-Structure Calulations

    Science.gov (United States)

    Pask, J. E.; Sterne, P. A.

    Over the course of the past two decades, the density functional theory (DFT) (see e.g., [1]) of Hohenberg, Kohn, and Sham has proven to be an accurate and reliable basis for the understanding and prediction of a wide range of materials properties from first principles (ab initio), with no experimental input or empirical parameters. However, the solution of the Kohn-Sham equations of DFT is a formidable task and this has limited the range of physical systems which can be investigated by such rigorous, quantum mechanical means. In order to extend the interpretive and predictive power of such quantum mechanical theories further into the domain of "real materials", involving nonstoichiometric deviations, defects, grain boundaries, surfaces, interfaces, and the like; robust and efficient methods for the solution of the associated quantum mechanical equations are critical. The finite-element (FE) method (see e.g., [2]) is a general method for the solution of partial differential and integral equations which has found wide application in diverse fields ranging from particle physics to civil engineering. Here, we discuss its application to large-scale ab initio electronic-structure calculations.

  7. AB INITIO SIMULATIONS FOR MATERIAL PROPERTIES ALONG THE JUPITER ADIABAT

    International Nuclear Information System (INIS)

    French, Martin; Becker, Andreas; Lorenzen, Winfried; Nettelmann, Nadine; Bethkenhagen, Mandy; Redmer, Ronald; Wicht, Johannes

    2012-01-01

    We determine basic thermodynamic and transport properties of hydrogen-helium-water mixtures for the extreme conditions along Jupiter's adiabat via ab initio simulations, which are compiled in an accurate and consistent data set. In particular, we calculate the electrical and thermal conductivity, the shear and longitudinal viscosity, and diffusion coefficients of the nuclei. We present results for associated quantities like the magnetic and thermal diffusivity and the kinematic shear viscosity along an adiabat that is taken from a state-of-the-art interior structure model. Furthermore, the heat capacities, the thermal expansion coefficient, the isothermal compressibility, the Grüneisen parameter, and the speed of sound are calculated. We find that the onset of dissociation and ionization of hydrogen at about 0.9 Jupiter radii marks a region where the material properties change drastically. In the deep interior, where the electrons are degenerate, many of the material properties remain relatively constant. Our ab initio data will serve as a robust foundation for applications that require accurate knowledge of the material properties in Jupiter's interior, e.g., models for the dynamo generation.

  8. ABS-NET: Fully Decentralized Runtime Adaptation for Distributed Objects

    Directory of Open Access Journals (Sweden)

    Karl Palmskog

    2013-10-01

    Full Text Available We present a formalized, fully decentralized runtime semantics for a core subset of ABS, a language and framework for modelling distributed object-oriented systems. The semantics incorporates an abstract graph representation of a network infrastructure, with network endpoints represented as graph nodes, and links as arcs with buffers, corresponding to OSI layer 2 interconnects. The key problem we wish to address is how to allocate computational tasks to nodes so that certain performance objectives are met. To this end, we use the semantics as a foundation for performing network-adaptive task execution via object migration between nodes. Adaptability is analyzed in terms of three Quality of Service objectives: node load, arc load and message latency. We have implemented the key parts of our semantics in a simulator and evaluated how well objectives are achieved for some application-relevant choices of network topology, migration procedure and ABS program. The evaluation suggests that it is feasible in a decentralized setting to continually meet both the objective of a node-balanced task allocation and make headway towards minimizing communication, and thus arc load and message latency.

  9. Improved radioimaging and tumor localization with monoclonal F(ab')2

    International Nuclear Information System (INIS)

    Wahl, R.L.; Parker, C.W.; Philpott, G.W.

    1983-01-01

    Monoclonal anti-tumor antibodies have great promise for radioimmunodetection and localization of tumors. Fab and F(ab')2 fragments, which lack the Fc fragment of antibody (Ab), are cleared more rapidly from the circulation and may have less nonspecific tissue binding than intact Ab. In radioimaging studies using a murine monoclonal antibody to carcinoembryonic antigen in a human colon carcinoma xenografted into hamsters, F(ab')2 fragments were shown superior to Fab fragments and intact antibody for scintiscanning. In double-label experiments with anti-CEA antibody and control monoclonal IgG, F(ab')2 fragments were found to give better and more rapid specific tumor localization than intact antibody or Fab fragments. F(ab')2 fragments offer significant promise for tumor imaging and possibly therapy

  10. Phosphoric acid doped AB-PBI membranes and its applications in high temperature PEMFC

    DEFF Research Database (Denmark)

    He, Ronghuan; Qingfeng, Li; Bjerrum, Niels

    2005-01-01

    Poly(2,5-benzimidazole) (ab-PBI) was prepared from 3,4-diaminobenzoic acid via a polymerisation reaction. The obtained polymer exhibits excellent thermal stability in a temperature range ….. The membrane of ab-PBI when doped with phosphoric acid at room temperaturepresents high proton conductivit......C with phosphoric acid doped ab-PBI as the electrolyte under atmospheric pressure at 200°C without humidification....

  11. R-matrix and RR-matrix calculations for cross sections for photoionization of outermost subshell in nobile gas atoms

    International Nuclear Information System (INIS)

    Tiwary, S.N.

    2000-02-01

    Photon impact integral ionization cross section (σ) as well as photoelectron asymmetry parameter (β) for the reactions hν+Ne(1s 2 2s 2 2p 6 ) → Ne + (1s 2 2s 2 2p 5 ) + e - , hν+Ar(1s 2 2s 2 2p 6 3s 2 3p 6 ) → Ar + (1s 2 2s 2 2p 6 3s 2 3p 5 ) + e - , hν+Kr(1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 6 ) → Kr + (1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 5 ) + e - and hν+Xe(1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 6 4d 10 5s 2 5p 6 ) → Xe + (1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 6 4d 10 5s 2 5p 5 ) + e - have been calculated in the L-S and j-j coupling schemes using Hartree-Fock (HF) wavefunctions within the reliable non-relativistic R-matrix as well as relativistic R-matrix (RR-matrix) methods in both the length and velocity gauges in the energy range of experimental data available. Comparison is made with all available experimental data as well as other theoretical results. Our present theoretical investigation clearly demonstrates that there is a good agreement between our present R-matrix results and RR-matrix results as well as with other results in the case of neon which reflects that the correlation and relativity are not important in this case, in the energy range of present consideration. Whereas in the case of xenon (Z=54), the independent-particle approximation completely breaks down, i.e., HF cross sections are both qualitatively as well as quantitatively incorrect in the entire energy range which exhibit that the multielectron correlation as well as relativity are both important but interchannel interactions are more important than the intrachannel interaction and relativity for obtaining high precision results. (author)

  12. Resíduos de glifosato e ácido aminometilfosfônico e teores de isoflavonas em soja BRS 244 RR e BRS 154 Residues of glyphosate and aminomethylphosphonic acid and levels of isoflavones in BRS 244 RR and BRS 154 soybean

    Directory of Open Access Journals (Sweden)

    Giani Mariza Bärwald Bohm

    2008-12-01

    Full Text Available A principal forma de controle das plantas daninhas durante o cultivo de soja geneticamente modificada (GM RR BRS 244 RR é o uso de glifosato. Porém, existem dúvidas quanto à segurança desse herbicida, à qualidade dos grãos e do solo da soja GM RR cultivada em Planossolo. Resíduos da molécula do glifosato e do metabólito ácido aminometilfosfônico (AMPA podem estar presentes nos grãos, bem como, podem afetar a concentração de isoflavonas. Por isso, avaliaram-se as sojas BRS 244 RR e BRS 154 cultivadas nos seguintes tratamentos: T1 - soja BRS 244 RR, sem aplicação de herbicida, com capina manual aos 28 dias após o plantio (dap; T2 - soja BRS 154 sem aplicação de herbicida, com capina manual também aos 28 dap; T3 - soja BRS 244 RR com uma aplicação de glifosato a 960 g ia ha-1 aos 28 dap; T4 - soja BRS 244 RR com duas aplicações de glifosato a 960 g ia ha-1 aos 28 e 56 dap; T5 - soja BRS 244 RR com uma aplicação de herbicida imazetapir a 100 g ia ha-1 aos 28 dap; T6 - soja BRS 154 com uma aplicação de herbicida imazetapir a 100 g ia ha-1 aos 28 dap. Verificou-se que a aplicação de glifosato no controle de plantas daninhas resultou em teores elevados de glifosato e ácido aminometilfosfônico no solo. Nos grãos, o teor de isoflavonas não parece ser significativamente afetado pela aplicação de glifosato, mas os resíduos desse herbicida foram superiores ao permitido pela legislação vigente, que é de 10 mg.kg-1.The use of Glyphosate is the best way to control weed growing when cultivating genetically modified soybean (GMRR BRS 244 RR. However, there have been doubts about the safety of this herbicide use concerning its effects on the quality of grains and on the soil of Albaqualf cultivated GMRR soybean. Glyphosate and the metabolite aminomethylphosphonic acid (AMPA residues can be present in the grains and affect the isoflavones concentration. Therefore, BRS 244 RR and BRS 154 soybeans with the following

  13. Comparative Study of Electroless Copper Film on Different Self-Assembled Monolayers Modified ABS Substrate

    Directory of Open Access Journals (Sweden)

    Jiushuai Xu

    2014-04-01

    Full Text Available Copper films were grown on (3-Mercaptopropyltrimethoxysilane (MPTMS, (3-Aminopropyltriethoxysilane (APTES and 6-(3-(triethoxysilylpropylamino-1,3,5- triazine-2,4-dithiol monosodium (TES self-assembled monolayers (SAMs modified acrylonitrile-butadiene-styrene (ABS substrate via electroless copper plating. The copper films were examined using scanning electron microscopy (SEM and X-ray diffraction (XRD. Their individual deposition rate and contact angle were also investigated to compare the properties of SAMs and electroless copper films. The results indicated that the formation of copper nuclei on the TES-SAMs modified ABS substrate was faster than those on the MPTMS-SAMs and APTES-SAMs modified ABS substrate. SEM images revealed that the copper film on TES-SAM modified ABS substrate was smooth and uniform, and the density of copper nuclei was much higher. Compared with that of TES-SAMs modified resin, the coverage of copper nuclei on MPTMS and APTES modified ABS substrate was very limited and the copper particle size was too big. The adhesion property test demonstrated that all the SAMs enhanced the interfacial interaction between copper plating and ABS substrate. XRD analysis showed that the copper film deposited on SAM-modified ABS substrate had a structure with Cu(111 preferred orientation, and the copper film deposited on TES-SAMs modified ABS substrate is better than that deposited on MPTMS-SAMs or APTES-SAMs modified ABS resins in electromigrtion resistance.

  14. Identification of Bacillus thuringiensis Cry1AbMod binding-proteins from Spodoptera frugiperda.

    Science.gov (United States)

    Martínez de Castro, Diana L; García-Gómez, Blanca I; Gómez, Isabel; Bravo, Alejandra; Soberón, Mario

    2017-12-01

    Bacillus thuringiensis Cry toxins are currently used for pest control in transgenic crops but evolution of resistance by the insect pests threatens the use of this technology. The Cry1AbMod toxin was engineered to lack the alpha helix-1 of the parental Cry1Ab toxin and was shown to counter resistance to Cry1Ab and Cry1Ac toxins in different insect species including the fall armyworm Spodoptera frugiperda. In addition, Cry1AbMod showed enhanced toxicity to Cry1Ab-susceptible S. frugiperda populations. To gain insights into the mechanisms of this Cry1AbMod-enhanced toxicity, we isolated the Cry1AbMod toxin binding proteins from S. frugiperda brush border membrane vesicles (BBMV), which were identified by pull-down assay and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The LC-MS/MS results indicated that Cry1AbMod toxin could bind to four classes of aminopeptidase (N1, N3, N4 y N5) and actin, with the highest amino acid sequence coverage acquired for APN 1 and APN4. In addition to these proteins, we found other proteins not previously described as Cry toxin binding proteins. This is the first report that suggests the interaction between Cry1AbMod and APN in S. frugiperda. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Development of Anti-lock Braking System (ABS) for Vehicles Braking

    Science.gov (United States)

    Minh, Vu Trieu; Oamen, Godwin; Vassiljeva, Kristina; Teder, Leo

    2016-11-01

    This paper develops a real laboratory of anti-lock braking system (ABS) for vehicle and conducts real experiments to verify the ability of this ABS to prevent the vehicle wheel from being locked while braking. Two controllers of PID and fuzzy logic are tested for analysis and comparison. This ABS laboratory is designed for bachelor and master students to simulate and analyze performances of ABS with different control techniques on various roads and load conditions. This paper provides educational theories and practices on the design of control for system dynamics.

  16. The combined benefits of motorcycle antilock braking systems (ABS) in preventing crashes and reducing crash severity.

    Science.gov (United States)

    Rizzi, Matteo; Kullgren, Anders; Tingvall, Claes

    2016-01-01

    Several studies have reported the benefits of motorcycle antilock braking systems (ABS) in reducing injury crashes, due to improved stability and braking performance. Both aspects may prevent crashes but may also reduce the crash severity when a collision occurs. However, it is still unknown to what extent the reductions in injury crashes with ABS may be due to a combination of these mechanisms. Swedish hospital and police reports (2003-2012) were used. The risk for permanent medical impairment (RPMI) was calculated, showing the risk of at least 1 or 10% permanent medical impairment. In total, 165 crashes involving ABS-equipped motorcycles were compared with 500 crashes with similar motorcycles without ABS. The analysis was performed in 3 steps. First, the reduction in emergency care visits with ABS was calculated using an induced exposure approach. Secondly, the injury mitigating effects of ABS were investigated. The mean RPMI 1+ and RPMI 10+ were analyzed for different crash types. The distributions of impairing injuries (PMI 1+) and severely impairing injuries (PMI 10+) were also analyzed. In the third step, the total reduction of PMI 1+ and PMI 10+ injured motorcyclists was calculated by combining the reductions found in the previous steps. An additional analysis of combined braking systems (CBS) together with ABS was also performed. The results showed that emergency care visits were reduced by 47% with ABS. In the second step, it was found that the mean RPMI 1+ and RPMI 10+ with ABS were 15 and 37% lower, respectively. Finally, the third step showed that the total reductions in terms of crash avoidance and mitigation of PMI 1+ and PMI 10+ injured motorcyclists with ABS were 67 and 55%, respectively. However, PMI 1+ and PMI 10+ leg injuries were not reduced by ABS to the same extent. Indications were found suggesting that the benefits of ABS together with CBS may be greater than ABS alone. This article indicated that motorcycle ABS reduced impairing injuries

  17. Global longitudinal strain corrected by RR interval is a superior predictor of all-cause mortality in patients with systolic heart failure and atrial fibrillation

    DEFF Research Database (Denmark)

    Modin, Daniel; Sengeløv, Morten; Jørgensen, Peter Godsk

    2017-01-01

    AIMS: Quantification of systolic function in patients with atrial fibrillation (AF) is challenging. A novel approach, based on RR interval correction, to counteract the varying heart cycle lengths in AF has recently been proposed. Whether this method is superior in patients with systolic heart fa...

  18. 75 FR 51654 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-22B and RB211-524 Series Turbofan Engines

    Science.gov (United States)

    2010-08-23

    ... engine shop visit is the induction of an engine into the shop for maintenance involving the separation of... Airworthiness Directives; Rolls-Royce plc (RR) RB211-22B and RB211-524 Series Turbofan Engines AGENCY: Federal... in the associated engine manual. The cracks have been found to initiate from corrosion pits...

  19. Cyclodialysis ab interno as a surgical approach to intractable glaucoma.

    Science.gov (United States)

    Jordan, Jens F; Dietlein, Thomas S; Dinslage, Sven; Lüke, Christoph; Konen, Walter; Krieglstein, Günter K

    2007-08-01

    In glaucoma filtration surgery, the problem of subconjunctival scarring has still not been satisfactorily solved. Suprachoroidal drainage of aqueous humour offers a promising, alternative option for intractable glaucoma. We here present a clinical study on the surgical approach of gonioscopic cyclodialysis ab interno. Twenty-eight eyes of 20 patients with intractable glaucoma were included in this prospective, consecutive, case-control study. The eyes had had a mean of 4.4 +/- 2.4 previous antiglaucomatous interventions. Baseline intraocular pressure (IOP) was 34.3 +/- 10.5 mmHg despite maximum therapy. Under gonioscopic control, cyclodialysis ab interno was performed over two clock times to gain access to the suprachoroidal space. No additional trabecular meshwork surgery was performed. Success was defined as a lowering of IOP to below 21 mmHg without the need for further medication or intervention. Mean postoperative IOP was 14.6 +/- 12.4 mmHg. Mean follow-up (FU) for all eyes was 121.8 days. After a mean of 60 days, 21 eyes (75%) needed further surgical intervention. Qualified success was seen in four eyes (14.3%), with a mean FU of 383.6 days. Three eyes (10.7%) showed absolute success after a mean FU period of 202.7 days. In our series, we obtained the best results for phakic eyes, followed by pseudophakic and aphakic eyes. The results of this study do not provide convincing evidence of the functional efficacy of cyclodialysis ab interno. Nevertheless, the technique is easy to perform and offers safe and atraumatic access to the resorptive capability of the choroid. Conjunctival manipulation is avoided. Contrary to reports in the current literature, in our series, the best results were obtained for phakic eyes, though the small number of eyes included does not allow reliable statistics. Further studies will need to focus on the use of different space-retaining substances or a widening of the cyclodialysis cleft to improve surgical outcome.

  20. Chemical Composition of RR Lyn – an Eclipsing Binary System with Am and λ Boo Type Components

    Directory of Open Access Journals (Sweden)

    Yeuncheol Jeong

    2017-06-01

    Full Text Available High-resolution spectroscopic observations of the eclipsing binary system RR Lyn were made using the 1.8 m telescope at the Bohuynsan Optical Astronomical Observatory in Korea. The spectral resolving power was R = 82,000, with a signal to noise ratio of S/N > 150. We found the effective temperatures and surface gravities of the primary and secondary components to be equal to Teff = 7,920 & 7,210 K and log(g = 3.80 & 4.16, respectively. The abundances of 34 and 17 different chemical elements were found in the atmospheric components. Correlations between the derived abundances with condensation temperatures and the second ionization potentials of these elements are discussed. The primary component is a typical metallic line star with the abundances of light and iron group elements close to solar values, while elements with atomic numbers Z > 30 are overabundant by 0.5–1.5 dex with respect to solar values. The secondary component is a λ Boo type star. In this type of stars, CNO abundances are close to solar values, while the abundance pattern shows a negative correlation with condensation temperatures.

  1. Solid-solution stability and preferential site-occupancy in (R-R')2Fe14B compounds

    Science.gov (United States)

    Colin, C. V.; Ito, M.; Yano, M.; Dempsey, N. M.; Suard, E.; Givord, D.

    2016-06-01

    The rare-earth (R) uniaxial anisotropy of R2Fe14B compounds with magnetic R atoms (e.g., Nd or Pr) is at the origin of the exceptional hard magnetic properties achieved in magnets based on these compounds. The uniaxial anisotropy found in Ce2Fe14B is attributed mainly to the magnetism of Fe. Ce is the most abundant R element and there has been much recent effort to fabricate magnets in which Ce is partially substituted for Nd. In the present neutron study of (R1-xCex)2Fe14B (R = La or Nd), Ce is found to enter the R2Fe14B phase over the entire composition range. The crystallographic parameters decrease with increasing Ce content and the Ce atoms preferentially occupy the smaller 4f sites. It is concluded that Ce in these (RR')2Fe14B compounds essentially maintains the intermediate valence character found in Ce2Fe14B. It is proposed that, in this intermediate valence state, Ce weakly contributes to uniaxial anisotropy, thus making a link with the fact that significant coercivity is preserved in Ce-substituted NdFeB magnets.

  2. Analysis of shot-peening and residual stress relaxation in the nickel-based superalloy RR1000

    International Nuclear Information System (INIS)

    Foss, B.J.; Gray, S.; Hardy, M.C.; Stekovic, S.; McPhail, D.S.; Shollock, B.A.

    2013-01-01

    This work assesses the residual stress relaxation of the nickel-based alloy RR1000 due to thermal exposure and dwell-fatigue loading. A number of different characterization methods, including X-ray residual stress analysis, electron back-scattered diffraction, microhardness testing and focused ion beam secondary electron imaging, contributed to a detailed study of the shot-peened region. Thermal exposure at 700 °C resulted in a large reduction in the residual stresses and work-hardening effects in the alloy, but the subsurface remained in a beneficial compressive state. Oxidizing environments caused recrystallization in the near surface, but did not affect the residual stress-relaxation behaviour. Dwell-fatigue loading caused the residual stresses to return to approximately zero at nearly all depths. This work forms part of an ongoing investigation to determine the effects of shot-peening in this alloy with the motivation to improve the fatigue and oxidation resistance at 700 °C

  3. Ab initio and kinetic modeling studies of formic acid oxidation

    DEFF Research Database (Denmark)

    Marshall, Paul; Glarborg, Peter

    2015-01-01

    A detailed chemical kinetic model for oxidation of formic acid (HOCHO) in flames has been developed, based on theoretical work and data from literature. Ab initio calculations were used to obtain rate coefficients for reactions of HOCHO with H, O, and HO2. Modeling predictions with the mechanism...... have been compared to the experimental results of de Wilde and van Tiggelen (1968) who measured the laminar burning velocities for HOCHO flames over a range of stoichiometries and dilution ratios. The modeling predictions are generally satisfactory. The governing reaction mechanisms are outlined based...... on calculations with the kinetic model. Formic acid is consumed mainly by reaction with OH, yielding OCHO, which dissociates rapidly to CO2 + H, and HOCO, which may dissociate to CO + OH or CO2 + H, or react with H, OH, or O2 to form more stable products. The branching fraction of the HOCHO + OH reaction, as well...

  4. Erythema ab igne: new technology rebounding upon its users?

    Science.gov (United States)

    Salgado, Fernanda; Handler, Marc Z; Schwartz, Robert A

    2018-04-01

    Erythema ab igne (EAI) is a persistent, chronic skin condition resulting from prolonged exposure to infrared radiation, experienced as heat. Once associated with traditional warming sources like wood burning stoves or open fires, modern, infrared exposure originates also from newer sources like laptops and heating pads and may be creating a rebound of EAI. The epidemiology may be different too, with younger patients than previously seen. Localized EAI over an area of pain in the abdomen or lower back can be a sign of an underlying disorder, including cancer. Prognosis of EAI is good, with removal of the heat source resulting in complete remission. In chronic cases in which premalignant cutaneous dysplasia has resulted, additional treatments may be necessary including topical retinoids, 5-fluorouracil cream, and laser treatments. Rarely, cancers such as squamous cell carcinoma, Merkel cell carcinoma, and cutaneous marginal zone B cell lymphoma have been associated with longstanding EAI. © 2017 The International Society of Dermatology.

  5. Erythema Ab igne after footbath with Chinese herbal remedies

    Directory of Open Access Journals (Sweden)

    Jeng-Feng Chen

    2011-01-01

    Full Text Available Erythema ab igne (EAI is a reticulated, telangiectatic, and hyperpigmented skin eruption resulting from chronic exposure to long-term moderate heat. The incidence has decreased substantially today because of the advent of modern central heating systems. Recently, we encountered a patient who developed EAI after 2 weeks of footbaths with Chinese herbal remedies, which she used to treat her acute ankle sprain. Alternative Chinese medicine, such as herbal footbath, is a prevalent medical practice to treat acute pains as well as many chronic musculoskeletal ailments among Chinese and Asian populations. It has also become increasingly popular in Western countries in the past decade. Herein, we would like to report an uncommon case of iatrogenic EAI caused by footbath and raise the attention of clinicians to such rare, potentially malignant-transforming, dermatosis.

  6. Monte Carlo simulation of the abBA experiment

    Science.gov (United States)

    Frlež, Emil

    2004-10-01

    The abBA collaboration proposes to conduct a program of precise measurements of neutron beta decay correlation coefficients a, b, A, and B at a cold neutron beam facility. We have performed studies of the energy and timing response of a pair of silicon detectors. To this end we have compared (i) the industry-standard SIMION 3D 7.0 program, and (ii) a GEANT4-based code with the addition of appropriate adiabatic invariants in simulating the propagation of the decay electrons and protons in the electromagnetic spectrometer. We use these results to examine the systematic effects and to determine the precision with which the physics parameters a, b, A, and B can be extracted in practice.

  7. Symplectic ab initio no-core shell model

    Energy Technology Data Exchange (ETDEWEB)

    Draayer, J. P.; Dytrych, T.; Sviratcheva, K. D.; Bahri, C. [Department of Physics and Astronomy, Lousiana State University, Baton Rouge, 70803 Lousiana (United States); Vary, J. P. [Department of Physics and Astronomy, Iowa State University, Ames, 50011 Iowa (United States)

    2008-12-15

    The present study confirms the significance of the symplectic Sp(3,R) symmetry in nuclear dynamics as unveiled, for the first time, by examinations of realistic nucleon-nucleon interactions as well as of eigenstates calculated in the framework of the ab initio No-Core Shell Model (NCSM). The results reveal that the NCSM wave functions for light nuclei highly overlap (at the {approx} 90% level) with only a few of the most deformed Sp(3,R)-symmetric basis states. This points to the possibility of achieving convergence of higher-lying collective modes and reaching heavier nuclei by expanding the NCSM basis space beyond its current limits through Sp(3,R) basis states. Furthermore the symplectic symmetry is found to be favored by the JISP 16 and CD-Bonn realistic nucleon-nucleon interactions, which points to a more fundamental origin of the symplectic symmetry. (Author)

  8. Molybdenum-titanium phase diagram evaluated from ab initio calculations

    Science.gov (United States)

    Barzilai, Shmuel; Toher, Cormac; Curtarolo, Stefano; Levy, Ohad

    2017-07-01

    The design of next generation β -type titanium implants requires detailed knowledge of the relevant stable and metastable phases at temperatures where metallurgical heat treatments can be performed. Recently, a standard specification for surgical implant applications was established for Mo-Ti alloys. However, the thermodynamic properties of this binary system are not well known and two conflicting descriptions of the β -phase stability have been presented in the literature. In this study, we use ab initio calculations to investigate the Mo-Ti phase diagram. These calculations predict that the β phase is stable over a wide concentration range, in qualitative agreement with one of the reported phase diagrams. In addition, they predict stoichiometric compounds, stable at temperatures below 300 ∘C , which have not yet been detected by experiments. The resulting solvus, which defines the transition to the β -phase solid solution, therefore occurs at lower temperatures and is more complex than previously anticipated.

  9. Maximizing planet packing in the alpha Centauri AB system

    Science.gov (United States)

    Quarles, Billy L.; Lissauer, Jack J.; Kaib, Nathan A.

    2017-06-01

    Recent observational searches have prompted a rebirth of inquiry surrounding the alpha Centauri AB system. Moreover, numerical studies have suggested that planets can form within dynamically stable zones close to the parent stars. Our previous work (Quarles & Lissauer 2016) determined how individual planets interact with the host binary and the dynamical imprint that arises on billion year timescales. We investigate how the prospects of stability can be altered due to interplanetary interactions within multiple planet systems orbiting either stellar component. We find that systems of tightly packed Earth-mass planets can persist on timescales greater than the age of the binary within each star’s habitable zone. Additionally, the number of planets and the spacing in mutual Hill radii depends on the assumed initial eccentricity due to a forced eccentricity induced by the binary companion.

  10. Ab initio dynamical exchange interactions in frustrated antiferromagnets

    Science.gov (United States)

    Simoni, Jacopo; Stamenova, Maria; Sanvito, Stefano

    2017-08-01

    The ultrafast response to an optical pulse excitation of the spin-spin exchange interaction in transition metal antiferromagnets is studied within the framework of the time-dependent spin-density functional theory. We propose a formulation for the full dynamical exchange interaction, which is nonlocal in space, and it is derived starting from ab initio arguments. Then, we investigate the effect of the laser pulse on the onset of the dynamical process. It is found that we can distinguish two types of excitations, both activated immediately after the action of the laser pulse. While the first one can be associated to a Stoner-like excitation and involves the transfer of spin from one site to another, the second one is related to the ultrafast modification of a Heisenberg-like exchange interaction and can trigger the formation of spin waves in the first few hundred femtoseconds of the time evolution.

  11. Superfluid 3He A-B surface tension

    International Nuclear Information System (INIS)

    Bartkowiak, M.; Haley, R.P.; Fisher, S.N.; Guenault, A.M.; Pickett, G.R.; Skyba, P.

    2003-01-01

    We have made two different measurements of interfacial energies below 300 μK, at zero pressure and in magnetic fields up to 400 mT. A variable magnetic field profile allows us to stabilize and precisely manipulate the position of the A-B interface. First, we can derive the difference in wall wetting energies from the behaviour of the phase boundary as it enters and exits a stack of glass capillary tubes. Secondly, we can measure the surface tension from the level of over- or under-magnetization needed to force the interface through an aperture. These are the first surface energy measurements in high magnetic fields in the zero-temperature limit. Our results are in surprising agreement with earlier measurements at high pressure close to T c

  12. Ab initio Eliashberg Theory: Making Genuine Predictions of Superconducting Features

    Science.gov (United States)

    Sanna, Antonio; Flores-Livas, José A.; Davydov, Arkadiy; Profeta, Gianni; Dewhurst, Kay; Sharma, Sangeeta; Gross, E. K. U.

    2018-04-01

    We present an application of Eliashberg theory of superconductivity to study a set of novel superconducting systems with a wide range of structural and chemical properties. The set includes three intercalated group-IV honeycomb layered structures, SH3 at 200 GPa (the superconductor with the highest measured critical temperature), the similar system SeH3 at 150 GPa, and a lithium doped mono-layer of black phosphorus. The theoretical approach we adopt is a recently developed, fully ab initio Eliashberg approach that takes into account the Coulomb interaction in a full energy-resolved fashion avoiding any free parameters like μ*. This method provides reasonable estimations of superconducting properties, including TC and the excitation spectra of superconductors.

  13. Ab initio electron propagator theory of molecular wires. I. Formalism.

    Science.gov (United States)

    Dahnovsky, Yu; Zakrzewski, V G; Kletsov, A; Ortiz, J V

    2005-11-08

    Ab initio electron propagator methodology may be applied to the calculation of electrical current through a molecular wire. A new theoretical approach is developed for the calculation of the retarded and advanced Green functions in terms of the electron propagator matrix for the bridge molecule. The calculation of the current requires integration in a complex half plane for a trace that involves terminal and Green's-function matrices. Because the Green's-function matrices have complex poles represented by matrices, a special scheme is developed to express these "matrix poles" in terms of ordinary poles. An expression for the current is derived for a terminal matrix of arbitrary rank. For a single terminal orbital, the analytical expression for the current is given in terms of pole strengths, poles, and terminal matrix elements of the electron propagator. It is shown that Dyson orbitals with high pole strengths and overlaps with terminal orbitals are most responsible for the conduction of electrical current.

  14. Ab initio Potential Energy Surface for H-H2

    Science.gov (United States)

    Partridge, Harry; Bauschlicher, Charles W., Jr.; Stallcop, James R.; Levin, Eugene

    1993-01-01

    Ab initio calculations employing large basis sets are performed to determine an accurate potential energy surface for H-H2 interactions for a broad range of separation distances. At large distances, the spherically averaged potential determined from the calculated energies agrees well with the corresponding results determined from dispersion coefficients; the van der Waals well depth is predicted to be 75 +/- (mu)E(sub h). Large basis sets have also been applied to reexamine the accuracy of theoretical repulsive potential energy surfaces. Multipolar expansions of the computed H-H2 potential energy surface are reported for four internuclear separation distances (1.2, 1.401, 1.449, and 1.7a(sub 0) of the hydrogen molecule. The differential elastic scattering cross section calculated from the present results is compared with the measurements from a crossed beam experiment.

  15. Reactive Monte Carlo sampling with an ab initio potential

    International Nuclear Information System (INIS)

    Leiding, Jeff; Coe, Joshua D.

    2016-01-01

    We present the first application of reactive Monte Carlo in a first-principles context. The algorithm samples in a modified NVT ensemble in which the volume, temperature, and total number of atoms of a given type are held fixed, but molecular composition is allowed to evolve through stochastic variation of chemical connectivity. We discuss general features of the method, as well as techniques needed to enhance the efficiency of Boltzmann sampling. Finally, we compare the results of simulation of NH 3 to those of ab initio molecular dynamics (AIMD). We find that there are regions of state space for which RxMC sampling is much more efficient than AIMD due to the “rare-event” character of chemical reactions.

  16. Thermal transport properties of antimonene: an ab initio study.

    Science.gov (United States)

    Wang, Shudong; Wang, Wenhua; Zhao, Guojun

    2016-11-16

    Searching for low thermal conductivity materials is crucial for thermoelectric devices. Here we report on the phonon transport properties of recently fabricated single layer antimony, antimonene [Ares, et al., Adv. Mater., 2016, 28, 6332]. Ab initio calculations in combination with the Boltzmann transport equation (BTE) for phonons show that antimonene has a low lattice thermal conductivity (15.1 W m -1 K -1 at 300 K), indicating its potential thermoelectric applications. The low lattice thermal conductivity is due to its small group velocity, low Debye temperature and large buckling height. We also investigate in detail the mode contributions to total thermal conductivity and find at low frequency that the longitudinal acoustic (LA) branch dominates the thermal conductivity. Moreover, we show that the lattice thermal conductivity of antimonene can further be reduced by minimizing the sample size. Our findings open the field for thermoelectric applications based on antimonene.

  17. Ab initio engineering of materials with stacked hexagonal tin frameworks

    Science.gov (United States)

    Shao, Junping; Beaufils, Clément; Kolmogorov, Aleksey N.

    2016-07-01

    The group-IV tin has been hypothesized to possess intriguing electronic properties in an atom-thick hexagonal form. An attractive pathway of producing sizable 2D crystallites of tin is based on deintercalation of bulk compounds with suitable tin frameworks. Here, we have identified a new synthesizable metal distannide, NaSn2, with a 3D stacking of flat hexagonal layers and examined a known compound, BaSn2, with buckled hexagonal layers. Our ab initio results illustrate that despite being an exception to the 8-electron rule, NaSn2 should form under pressures easily achievable in multi-anvil cells and remain (meta)stable under ambient conditions. Based on calculated Z2 invariants, the predicted NaSn2 may display topologically non-trivial behavior and the known BaSn2 could be a strong topological insulator.

  18. Ab initio studies on proton affinities of substituted furans

    International Nuclear Information System (INIS)

    Lee, Gab Yong; Lee, Hyun Mee

    1998-01-01

    The geometry of furan, relevant to the binding of bis-furan lexitropsin that contains this ring to the base pair of minor groove of DNA, is optimized by semiempirical (MNDO) and ab initio (Hartree-Fock) methods. The proton affinity and electronic structure are evaluated at the 6-31G and 6-31G level of theory for the optimized geometry. The proton affinities are also studied for various substituted furans with the electron donating and -withdrawing groups to estimate the substituent effect on the proton affinity of furans. It has been found that the electron-donating substituents increase the proton affinity of of furan, whereas the electron-withdrawing substituents decrease it. This result can be explained with atomic charge and electron density at oxygen of substituted furans

  19. Modeling Deployment Decisions for Elastic Services with ABS

    Directory of Open Access Journals (Sweden)

    Einar Broch Johnsen

    2016-10-01

    Full Text Available The use of cloud technology can offer significant savings for the deployment of services, provided that the service is able to make efficient use of the available virtual resources to meet service-level requirements. To avoid software designs that scale poorly, it is important to make deployment decisions for the service at design time, early in the development of the service itself. ABS offers a formal, model-based approach which integrates the design of services with the modeling of deployment decisions. In this paper, we illustrate the main concepts of this approach by modeling a scalable pool of workers with an auto-scaling strategy and by using the model to compare deployment decisions with respect to client traffic with peak loads.

  20. Quantum plasmonics: from jellium models to ab initio calculations

    Directory of Open Access Journals (Sweden)

    Varas Alejandro

    2016-08-01

    Full Text Available Light-matter interaction in plasmonic nanostructures is often treated within the realm of classical optics. However, recent experimental findings show the need to go beyond the classical models to explain and predict the plasmonic response at the nanoscale. A prototypical system is a nanoparticle dimer, extensively studied using both classical and quantum prescriptions. However, only very recently, fully ab initio time-dependent density functional theory (TDDFT calculations of the optical response of these dimers have been carried out. Here, we review the recent work on the impact of the atomic structure on the optical properties of such systems. We show that TDDFT can be an invaluable tool to simulate the time evolution of plasmonic modes, providing fundamental understanding into the underlying microscopical mechanisms.

  1. Non-stoichiometric AB5 alloys for metal hydride electrodes

    Science.gov (United States)

    Reilly, James J.; Adzic, Gordana D.; Johnson, John R.; Vogt, Thomas; McBreen, James

    2001-01-01

    The present invention provides a non-stoichiometric alloy comprising a composition having the formula AB.sub.5+X an atomic ratio wherein A is selected from the group consisting of the rare earth metals, yttrium, mischmetal, or a combination thereof; B is nickel and tin, or nickel and tin and at least a third element selected from the group consisting of the elements in group IVA of the periodic table, aluminum, manganese, iron, cobalt, copper, antimony or a combination thereof; X is greater than 0 and less than or equal to about 2.0; and wherein at least one substituted A site is occupied by at least one of the B elements. An electrode incorporating said alloy and an electrochemical cell incorporating said electrode are also described.

  2. Constructing ab initio and empirical potential energy surfaces for water

    International Nuclear Information System (INIS)

    Kain, Jacqueline Sophie

    2001-01-01

    The infrared spectrum of water is possibly one of the most well studied and yet portions of it are still poorly understood. Recently, significant advances have been made in assigning water spectra using variational nuclear calculations. The major factor determining the accuracy of ro-vibrational spectra of water is the accuracy of the underlying Potential Energy Surface. Even the most accurate ab initio Potential Energy Surface does not reproduce the Born-Oppenheimer surface to sufficient accuracy for spectroscopic studies. Furthermore, effects beyond this model such as the adiabatic correction, the relativistic correction and the non-adiabatic correction have to be considered. This thesis includes a discussion on how the relativistic correction was calculated, for the water molecule, from first-order perturbation theory. The relativistic correction improved vibrational stretching motion while making the prediction of the bending modes far worse. For rotational motion the relativistic effect had an increasing effect with increasing Ka. A further alteration to the ab initio calculations is introduced by adjusting the barrier to linearity in the water potential. This alteration to the barrier was considered in order to compensate for the lack of convergence of quantum chemical calculations of the Born-Oppenheimer surface. This barrier attempts to represent the change in the potential from linear to equilibrium. We show the improvements this has on the calculated energy levels by comparison with the HITRAN database. This then led the way to the improved spectroscopic potential presented here in this thesis. This new spectroscopic potential reduces the overall standard deviation significantly for vibrational and rotational energy levels. (author)

  3. Effect of gamma irradiation on nutritional components and Cry1Ab protein in the transgenic rice with a synthetic cry1Ab gene from Bacillus thuringiensis

    International Nuclear Information System (INIS)

    Wu Dianxing; Ye Qingfu; Wang Zhonghua; Xia Yingwu

    2004-01-01

    The effects of gamma irradiation on the transgenic rice containing a synthetic cry1Ab gene from Bacillus thuringiensis were investigated. There was almost no difference in the content of the major nutritional components, i.e. crude protein, crude lipid, eight essential amino acids and total ash between the irradiated grains and the non-irradiated transgenic rice. However, the amounts of Cry1Ab protein and apparent amylose in the irradiated transgenic rice were reduced significantly by the doses higher than 200 Gy. In vivo observation showed that Cry1Ab protein contents also decreased in the fresh leaf tissues of survival seedlings after irradiation with 200 Gy or higher doses and showed inhibition of seedling growth. The results indicate that gamma irradiation might improve the quality of transgenic rice due to removal of the toxic Cry1Ab protein

  4. Cell Culture Systems To Study Human Herpesvirus 6A/B Chromosomal Integration.

    Science.gov (United States)

    Gravel, Annie; Dubuc, Isabelle; Wallaschek, Nina; Gilbert-Girard, Shella; Collin, Vanessa; Hall-Sedlak, Ruth; Jerome, Keith R; Mori, Yasuko; Carbonneau, Julie; Boivin, Guy; Kaufer, Benedikt B; Flamand, Louis

    2017-07-15

    Human herpesviruses 6A/B (HHV-6A/B) can integrate their viral genomes in the telomeres of human chromosomes. The viral and cellular factors contributing to HHV-6A/B integration remain largely unknown, mostly due to the lack of efficient and reproducible cell culture models to study HHV-6A/B integration. In this study, we characterized the HHV-6A/B integration efficiencies in several human cell lines using two different approaches. First, after a short-term infection (5 h), cells were processed for single-cell cloning and analyzed for chromosomally integrated HHV-6A/B (ciHHV-6A/B). Second, cells were infected with HHV-6A/B and allowed to grow in bulk for 4 weeks or longer and then analyzed for the presence of ciHHV-6. Using quantitative PCR (qPCR), droplet digital PCR, and fluorescent in situ hybridization, we could demonstrate that HHV-6A/B integrated in most human cell lines tested, including telomerase-positive (HeLa, MCF-7, HCT-116, and HEK293T) and telomerase-negative cell lines (U2OS and GM847). Our results also indicate that inhibition of DNA replication, using phosphonoacetic acid, did not affect HHV-6A/B integration. Certain clones harboring ciHHV-6A/B spontaneously express viral genes and proteins. Treatment of cells with phorbol ester or histone deacetylase inhibitors triggered the expression of many viral genes, including U39 , U90 , and U100 , without the production of infectious virus, suggesting that the tested stimuli were not sufficient to trigger full reactivation. In summary, both integration models yielded comparable results and should enable the identification of viral and cellular factors contributing to HHV-6A/B integration and the screening of drugs influencing viral gene expression, as well as the release of infectious HHV-6A/B from the integrated state. IMPORTANCE The analysis and understanding of HHV-6A/B genome integration into host DNA is currently limited due to the lack of reproducible and efficient viral integration systems. In the

  5. Comparison Between Structures and Properties of ABS Nanocomposites Derived from Two Different Kinds of OMT

    Science.gov (United States)

    Cai, Yibing; Huang, Fenglin; Xia, Xin; Wei, Qufu; Tong, Xutao; Wei, Anfang; Gao, Weidong

    2010-03-01

    In the present work, the hexadecyl triphenyl phosphonium bromide (P16) and cetyl pyridium chloride (CPC) were used to modify montmorillonite (MMT) based on the structural characteristic of the engineering thermoplastic acrylonitrile-butadiene-styrene copolymer (ABS) and the principle of “like dissolves like”, and then used to prepare the ABS/organic-modified montmorillonite (OMT) nanocomposites by melt-intercalation method. The influences of two different kinds of OMT on the structures and properties of the ABS nanocomposites were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution electron microscopy (HREM), thermogravimetric analyses (TGA), Cone calorimetry and dynamic mechanical analyses (DMA), respectively. The increased basal spacing showed that ABS intercalated into the gallery of the OMT. The morphology indicated that the OMT dispersed well in the ABS resin and the intercalated structure for ABS/OMT-P16 nanocomposites and intercalated-exfoliated structure for ABS/OMT-CPC nanocomposites were respectively formed. The TGA results revealed that onset temperature of thermal degradation and charred residue at 700 °C of the ABS nanocomposites was remarkably enhanced compared to the pure ABS. It was also found from the Cone calorimetry tests that the peak of heat release rate (PHRR) decreased significantly, contributing to the reduced flammability. The DMA measurements indicated that the loading of silicate clays improved the storage modulus of the ABS resin. The partial exfoliation of the OMT-CPC within ABS nanocomposites was advantageous to increasing thermal stability properties, decreasing flammability properties, and improving mechanical properties.

  6. Preclinical profile of AB-423, an inhibitor of Hepatitis B virus pgRNA encapsidation.

    Science.gov (United States)

    Mani, Nagraj; Cole, Andrew G; Phelps, Janet R; Ardzinski, Andrzej; Cobarrubias, Kyle D; Cuconati, Andrea; Dorsey, Bruce D; Evangelista, Ellen; Fan, Kristi; Guo, Fang; Guo, Haitao; Guo, Ju-Tao; Harasym, Troy O; Kadhim, Salam; Kultgen, Steven G; Lee, Amy C H; Li, Alice H L; Long, Quanxin; Majeski, Sara A; Mao, Richeng; McClintock, Kevin D; Reid, Stephen P; Rijnbrand, Rene; Snead, Nicholas M; Micolochick Steuer, Holly M; Stever, Kim; Tang, Sunny; Wang, Xiaohe; Zhao, Qiong; Sofia, Michael J

    2018-03-19

    AB-423 is a sulfamoylbenzamide (SBA) class of HBV capsid inhibitor in Phase 1 clinical trials. In cell culture models AB-423 showed potent inhibition of HBV replication (EC 50 /EC 90 = 0.08-0.27 μM/0.33-1.32 μM) with no significant cytotoxicity (CC 50 >10 μM). Addition of 40% human serum resulted in a 5-fold increase in the EC 50 values. AB-423 inhibited HBV genotypes A through D and nucleos/tide-resistant variants in vitro Treatment of HepDES19 cells with AB-423 resulted in capsid particles devoid of encapsidated pgRNA and rcDNA indicating it is a class II capsid inhibitor. In a de novo infection model AB-423 prevented the conversion of encapsidated rcDNA to cccDNA presumably by interfering with the capsid uncoating process. Molecular docking of AB-423 into crystal structures of heteroaryldihydropyrimidines and an SBA and biochemical studies suggest that AB-423 likely also binds to the dimer:dimer interface of core protein. In vitro dual combination studies with AB-423 and anti-HBV agents such as nucleos/tide analogs, RNAi agents, or interferon-α resulted in additive to synergistic antiviral activity. Pharmacokinetic studies with AB-423 in CD-1 mice showed significant systemic exposures and higher liver accumulation. A 7-day BID administration of AB-423 in a hydrodynamic injection mouse model of HBV model resulted in a dose-dependent reduction in serum HBV DNA levels and combination with ETV or ARB-1467 resulted in a trend towards greater antiviral activity than either agent alone consistent with the results of the in vitro combination studies. The overall preclinical profile of AB-423 supports further evaluation for safety, pharmacokinetics and antiviral activity in CHB patients. Copyright © 2018 American Society for Microbiology.

  7. Quality assessment of fruit pulps industrialized and commercialized in the city of Boa Vista – RR = Avaliação da qualidade de polpas de frutos industrializadas e comercializadas no município de Boa Vista – RR

    Directory of Open Access Journals (Sweden)

    Cássia Rejane Nascimento

    2012-12-01

    Full Text Available This work aimed to study the quality of frozen pulp, manufactured and marketed in Boa Vista - RR, through physico-chemical analysis. It were selected six Agroindustries that produce and market pulp in establishments located in Fair Passarão, supermarkets and home of juices, identified by the letters A, B, C, D, E and F. The variables studied were: soluble solids, titratable acidity and vitamin C, of the flavors: acerola, caja, cupuaçu, guava, soursop and passion fruit. The experiment was conducted in completely randomized design, being analyzed six brands of fruits pulps and six different fruits, with three replicates. The observed results demonstrate that none of the companies processing fruit pulp detail their identification inaccordance with the legislation. In the variables studied, only the cupuaçu pulp brands C and D and soursop brands B, C, D and E were in accordance with the technical regulation for fixing the identity and quality standard. Considering the variables in question, it was found that variations in the levels encountered and not adequacy of these standards could be minimized by the standardization of raw materials and processes used. =Objetivou-se com o presente trabalho estudar a qualidade de polpas congeladas, fabricadas e comercializadas no município de Boa Vista – RR, por meio de análises físico-químicas. Foram selecionadas seis Agroindústrias que produzem polpa e comercializam em estabelecimentos próprios localizados na Feira do Passarão, supermercados e casa de sucos, sendo identificadas pelas letras A, B, C, D, E e F. As variáveis estudadas foram: sólidos solúveis, acidez titulável e vitamina C, dos sabores: acerola, cajá, cupuaçu, goiaba, graviola e maracujá. O experimento foi conduzido em delineamento inteiramentecasualizado, sendo analisadas seis marcas de polpas e seis frutos diferentes, com três repetições. Os resultados observadosdemonstram que nenhuma das empresas de processamento de polpa

  8. Expression of Cry1Ab and Cry2Ab by a polycistronic transgene with a self-cleavage peptide in rice.

    Directory of Open Access Journals (Sweden)

    Qichao Zhao

    Full Text Available Insect resistance to Bacillus thuringiensis (Bt crystal protein is a major threat to the long-term use of transgenic Bt crops. Gene stacking is a readily deployable strategy to delay the development of insect resistance while it may also broaden insecticidal spectrum. Here, we report the creation of transgenic rice expressing discrete Cry1Ab and Cry2Ab simultaneously from a single expression cassette using 2A self-cleaving peptides, which are autonomous elements from virus guiding the polycistronic viral gene expression in eukaryotes. The synthetic coding sequences of Cry1Ab and Cry2Ab, linked by the coding sequence of a 2A peptide from either foot and mouth disease virus or porcine teschovirus-1, regardless of order, were all expressed as discrete Cry1Ab and Cry2Ab at high levels in the transgenic rice. Insect bioassays demonstrated that the transgenic plants were highly resistant to lepidopteran pests. This study suggested that 2A peptide can be utilized to express multiple Bt genes at high levels in transgenic crops.

  9. Embedded atom approach for gold–silicon system from ab initio

    Indian Academy of Sciences (India)

    In the present paper, an empirical embedded atom method (EAM) potential for gold–silicon (Au–Si) is developed by fitting to ab initio force (the 'force matching' method) and experimental data. The force database is generated within ab initio molecular dynamics (AIMD). The database includes liquid phase at various ...

  10. Polycarbonate and co-continuous polycarbonate/ABS blends: influence of specimen thickness

    NARCIS (Netherlands)

    Inberg, J.P.F.; Gaymans, R.J.

    2002-01-01

    The influence of specimen thickness on the fracture behaviour of polycarbonate (PC) and co-continuous PC/ABS (50/50) blends was studied in single edge notch tensile tests at 1 m/s and different temperatures (−80 to 130 °C). Specimen thickness ranged from 0.1 to 8 mm. In the co-continuous PC/ABS

  11. Ab initio and Gordon--Kim intermolecular potentials for two nitrogen molecules

    International Nuclear Information System (INIS)

    Ree, F.H.; Winter, N.W.

    1980-01-01

    Both ab initio MO--LCAO--SCF and the electron-gas (or Gordon--Kim) methods have been used to compute the intermolecular potential (Phi) of N 2 molecules for seven different N 2 --N 2 orientations. The ab initio calculations were carried out using a [4s3p] contracted Gaussian basis set with and without 3d polarization functions. The larger basis set provides adequate results for Phi>0.002 hartree or intermolecular separations less than 6.5--7 bohr. We use a convenient analytic expression to represent the ab initio data in terms of the intermolecular distance and three angles defining the orientations of the two N 2 molecules. The Gordon--Kim method with Rae's self-exchange correction yields Phi, which agrees reasonably well over a large repulsive range. However, a detailed comparison of the electron kinetic energy contributions shows a large difference between the ab initio and the Gordon--Kim calculations. Using the ab initio data we derive an atom--atom potential of the two N 2 molecules. Although this expression does not accurately fit the data at some orientations, its spherical average agrees with the corresponding average of the ab initio Phi remarkably well. The spherically averaged ab initio Phi is also compared with the corresponding quantities derived from experimental considerations. The approach of the ab initio Phi to the classical quadrupole--quadrupole interaction at large intermolecular separation is also discussed

  12. AB(2) functional polyesters via ring opening polymerization: synthesis and characterization

    NARCIS (Netherlands)

    Velthoen, I.W.; Dijkstra, Pieter J.; Feijen, Jan

    2009-01-01

    Aliphatic AB2 functional polyesters were conveniently prepared by the ring opening polymerization of ε-caprolactone and L-lactide in the presence of the AB2 functional initiator 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) and Sn(Oct)2 as the catalyst. In L-lactide polymerization, both bis-MPA

  13. Embedded atom approach for gold–silicon system from ab initio ...

    Indian Academy of Sciences (India)

    In the present paper, an empirical embedded atom method (EAM) potential for gold–silicon (Au–Si) is developed by fitting to ab initio force (the 'force matching' method) and experimental data. The force database is generated within ab initio molecular dynamics (AIMD). The database includes liquid phase at various ...

  14. Essentially Small Riemann Sums Fungsi Terintegral Henstock-dunford Pada [A,b

    OpenAIRE

    Solikhin; Sumanto, Y.D; Khabibah, Siti

    2014-01-01

    In this paper we study Henstock-Dunford integral on [a,b]. We discuss some properties of the integrable. We shall define essentially small Riemann sums (ESRS) and show that it is necessary and sufficient condition for function to be Henstock-Dunford integral on [a,b].

  15. Ab interno trabeculectomy: ultrastructural evidence and early tissue response in a human eye.

    Science.gov (United States)

    Ferrari, Ettore; Ortolani, Fulvia; Petrelli, Lucia; Contin, Magali; Pognuz, Derri Roman; Marchini, Maurizio; Bandello, Francesco

    2007-10-01

    To report the results of ultrastructural analysis of the postoperative effects of ab interno trabeculectomy in a human eye. Department of Ophthalmology, Palmanova Hospital, Palmanova, Udine, Italy. A 60-year-old woman with cataract and glaucoma had enucleation for a choroidal melanoma 10 days after ab interno trabeculectomy combined with phacoemulsification. A second ab interno trabeculectomy was performed after enucleation to evaluate the outcomes of the previous trabeculectomy. Light and transmission electron microscopy analyses were performed on samples excised from areas (1) not subjected to a procedure (control samples), (2) that had ab interno trabeculectomy before enucleation, and (3) that had ab interno trabeculectomy immediately after enucleation. Control samples showed normal trabecular features. Semithin sections of all ab interno trabeculectomy samples showed full-thickness removal of trabeculum segments, with Schlemm's canal lumen opening into the anterior chamber and apparent preservation of the adjacent structures. On ultrathin sections of samples that had ab interno trabeculectomy before enucleation, the endothelium lining the outer wall of Schlemm's canal and other angle components showed intact ultrastructural features. In trabecular beams that were not removed, the extracellular matrix appeared to have maintained its fine texture and was free of activated fibroblasts or leucocyte infiltrates. Observations confirm that ab interno trabeculectomy causes direct communication between Schlemm's canal lumen and the anterior chamber in vivo and immediately after enucleation during the early postoperative period. The absence of an evident inflammatory reaction in the examined case should be considered with caution because of possible tumor-induced immune suppression.

  16. Leonid Apananski müüs AB Grupi maa oma firmale / Silva Männik

    Index Scriptorium Estoniae

    Männik, Silva, 1974-

    1999-01-01

    Ilmunud ka: Den za Dnjom Nov/26 lk. 8. Apananski müüs AB Kindlustuse Grupile kuulunud Maakri tänava kinnistu. Skeem: AB Grupist on välja viidud ligikaudu 70 milj. krooni. Ilmunud ka: Den za Dnjom 23. nov. lk. 3

  17. Application of Cry1Ab/Ac Bt strip for screening of resistance for ...

    African Journals Online (AJOL)

    In this study, the efficacy of using Cry1Ab/Ac Bt strip for detecting Maruca resistant transgene in transgenic cowpea was systematically investigated for the first time through field derived progenies. The results show ... Keywords: Bacillus thuriengiensis, Cry1Ab/Ac Bt strips, transgenic cowpea, Maruca vitrata. African Journal of ...

  18. Inhibition of cholera toxin and other AB toxins by polyphenolic compounds

    Science.gov (United States)

    All AB-type protein toxins have intracellular targets despite an initial extracellular location. These toxins use different methods to reach the cytosol and have different effects on the target cell. Broad-spectrum inhibitors against AB toxins are therefore hard to develop because the toxins use dif...

  19. Die gesprek tussen AB du Toit en EP Sanders oor Paulus en die ...

    African Journals Online (AJOL)

    Die pad vorentoe. PF Craffert. Universiteit van Suid-Afrika. Abstract. The debate between AB du Toit and EP Sanders on. Paul and Palestinian Judaism: The road ahead. The aim of the article is to analyse the underlying structure of the critical reaction of AB du Toit against. EP Sanders's Pauline interpretation. It is shown that.

  20. Engine with hydraulic fuel injection and ABS circuit using a single high pressure pump

    Science.gov (United States)

    Bartley, Bradley E.; Blass, James R.; Gibson, Dennis H.

    2001-01-01

    An engine system comprises a hydraulically actuated fuel injection system and an ABS circuit connected via a fluid flow passage that provides hydraulic fluid to both the fuel injection system and to the ABS circuit. The hydraulically actuated system includes a high pressure pump. The fluid control passage is in fluid communication with an outlet from the high pressure pump.

  1. Influence of Cellulose on the Mechanical and Thermal Stability of ABS Plastic Composites

    Directory of Open Access Journals (Sweden)

    K. Crews

    2016-01-01

    Full Text Available Microcrystalline cellulose was explored as possible biodegradable fillers in the fabrication of ABS plastic composites. TGA indicates that upon inclusion of cellulose microcrystals the thermal stability of the ABS plastics was improved significantly when compared to the neat ABS plastic counterparts. Furthermore, inclusion of extracted cellulose from plant biomass showed a higher thermal stability with maximum decomposition temperatures around 131.95°C and 124.19°C for cellulose from cotton and Hibiscus sabdariffa, respectively, when compared to that of the purchased cellulose. In addition, TMA revealed that the average CTE value for the neat ABS and 1 : 1 ratio of cellulose to ABS fabricated in this study was significantly lower than the reported CTE (ca. 73.8 μm/m°C.

  2. Preparation of a pure 99mTc-F(ab')2 radioimmunoconjugate by direct labeling methods

    International Nuclear Information System (INIS)

    Griffiths, G.L.; Jones, A.L.; Hansen, H.J.; Goldenberg, D.M.

    1994-01-01

    Intact IgG and Fab' can be labeled directly with 99m Tc to give quantitative incorporation of radioactivity into the protein. With F(ab') 2 the reductive conditions yield a mixture of 99m Tc-F(ab') 2 and 99m Tc-Fab'. We now report a direct labeling method to produce only 99m Tc-F(ab') 2 in quantitative yield and contaminated with 99m Tc-Fab'. The properties, stability and biodistribution of the 99m Tc-F(ab') 2 have been compared to 99m Tc-Fab'. This new technology will allow us to compare technetium direct-labeled IgG, F(ab') 2 and Fab' derivatives of the same antibody for radioimmunodetection. (author)

  3. FTIR analysis on aging characteristics of ABS/PC blend under UV-irradiation in air

    Science.gov (United States)

    Li, Jiarong; Chen, Fu; Yang, Long; Jiang, Long; Dan, Yi

    2017-09-01

    Fourier Transform Infrared Spectroscopy (FTIR) is adopted to study the aging characteristics of poly(acrylonitrile-butadiene-styrene)/polycarbonate (ABS/PC) blend under UV-irradiation in air by analyzing the variation of the three main absorbance at about 967 cm- 1, 1720 cm- 1 and 3420 cm- 1 associated with carbon-hydrogen bonds belonging to 1,4 butadiene, carbonyl and hydroxyl groups, respectively. Results indicate that, under UV-irradiation in air, the photo-oxidation of the blend is not a simple combination of the photo-oxidation of corresponding ABS and PC themselves and takes place predominantly at the ABS component. Due to the interaction between the two components and the Fries rearrangement taken place in the PC component during the UV-irradiation in air, the ABS/PC blends behave higher photo-stability than ABS has.

  4. Summation of Parquet diagrams as an ab initio method in nuclear structure calculations

    International Nuclear Information System (INIS)

    Bergli, Elise; Hjorth-Jensen, Morten

    2011-01-01

    Research highlights: → We present a Green's function based approach for doing ab initio nuclear structure calculations. → In particular the sum the subset of so-called Parquet diagrams. → Applying the theory to a simple but realistic model, results in good agreement with other ab initio methods. → This opens up for ab initio calculations for medium-heavy nuclei. - Abstract: In this work we discuss the summation of the Parquet class of diagrams within Green's function theory as a possible framework for ab initio nuclear structure calculations. The theory is presented and some numerical details are discussed, in particular the approximations employed. We apply the Parquet method to a simple model, and compare our results with those from an exact solution. The main conclusion is that even at the level of approximation presented here, the results shows good agreement with other comparable ab initio approaches.

  5. Qualidade fisiológica de sementes de soja convencional e transgênica RR produzidas sob aplicação foliar de manganês

    Directory of Open Access Journals (Sweden)

    Everson Reis Carvalho

    2014-09-01

    Full Text Available Sementes de soja com alta qualidade fisiológica são essenciais à obtenção de produtividade elevada e um dos fatores que afetam a produção de sementes é a nutrição mineral. O objetivo neste trabalho foi avaliar o efeito da aplicação foliar de manganês, em diferentes doses e estádios de aplicação, na qualidade fisiológica de sementes de soja, em cultivares convencionais e em suas derivadas transgênicas RR, com distintos teores de lignina do tegumento. O ensaio foi conduzido em blocos casualizados, com três repetições e esquema fatorial 4 x 4 x 2, sendo quatro cultivares de soja, duas convencionais e suas derivadas transgênicas RR (BRS Celeste e BRS Baliza RR; BRSGO Jataí e BRS Silvânia RR, quatro doses de Mn via foliar (0; 200; 400 e 600 g Mn ha-1 e dois estádios de aplicação (R1 e R3. A qualidade fisiológica das sementes foi estimada, antes e após seis meses de armazenamento, por meio dos testes: Germinação, Envelhecimento acelerado, Emergência de plântulas, Condutividade elétrica e Tetrazólio (Viabilidade, vigor e danos mecânicos. Realizou-se também a quantificação de lignina no tegumento das sementes. A aplicação foliar de Mn proporciona incrementos na qualidade fisiológica nas sementes de soja produzidas. Sementes das cultivares de soja Celeste e Baliza RR apresentam melhor qualidade fisiológica quando comparadas às de Jataí e Silvânia RR. Sementes de cultivares de soja com maior teor de lignina no tegumento não apresentam necessariamente melhor qualidade fisiológica, sendo a qualidade das sementes relacionada a outros fatores intrínsecos ao genótipo.

  6. Radioimmunoimaging using F(ab')2 fragment of monoclonal antibodies against human alpha-fetoprotein

    International Nuclear Information System (INIS)

    Sakahara, Harumi; Endo, Keigo; Nakashima, Tetsuo; Koizumi, Mitsuru; Ohta, Hitoya; Torizuka, Kanji; Okada, Kenichiro; Yoshida, Osamu; Nishi, Shinzo.

    1985-01-01

    Using monoclonal antibodies against human α-fetoprotein (AFP), radioiodinated F(ab') 2 fragments were compared with whole IgG as a radiotracer for radioimmunoimaging of cancer. F(ab') 2 fragments were obtained by pepsin digestion of whole IgG (IgGl). IgG and F(ab') 2 were labeled with 125 I or 131 I by the chloramine-T method with almost full retention of antibody activity. F(ab') 2 fragments were cleared more rapidly from the circulation in normal mice with a half life of 6.3 hours than whole IgG with a half life of 5.5 days. Radioactivity of F(ab') 2 in various organs also decreased faster than IgG. In nude mice transplanted with AFP-producing human testicular tumor, F(ab') 2 fragments demonstrated superior scintigrams to whole IgG at 2 days after the injection, because of the fast disappearance of background radioactivity. Although absolute accumulation of 131 I labeled F(ab') 2 in the tumor was less than that of 131 I labeled IgG, tumor to other organ ratios were much higher with F(ab') 2 than those of IgG. The tumor to blood ratio of 131 I labeled F(ab') 2 was 1.04 at day 2, whereas tumor to blood ratio of 131 I labeled IgG was 0.55 at day 2 and 0.92 at day 4, respectively. These results indicated that for the radiolabeling of monoclonal antibodies, F(ab') 2 fragments would be superior to whole IgG in the radioimmunoimaging of cancer. (author)

  7. Acúmulo de nutrientes em soja convencional e soja RR em diferentes tipos de controle de planta daninha Nutrient accumulation in conventional and glyphosate-resistant soybean under different types of weed control

    Directory of Open Access Journals (Sweden)

    L.H.S. Zobiole

    2012-03-01

    Full Text Available O cultivo da soja - Glycine max (Roundup Ready® - RR tem aumentado, e pouco tem sido relatada a influência do glyphosate sobre o estado nutricional das plantas. O objetivo deste trabalho foi comparar o acúmulo de nutrientes em diferentes estádios fenológicos entre os cultivares BRS 184 (convencional e BRS 243 RR (transgênico, com mesmo ciclo vegetativo e reprodutivo, sob diferentes sistemas de manejo de plantas daninhas (capina e herbicida. O acúmulo de nutrientes e matéria seca na soja convencional foi superior ao da soja RR tratada com glyphosate, indicando que um nível maior de nutrientes pode ser requerido pelos cultivares RR para atingir a eficiência fisiológica e, provavelmente, uma nova recomendação de adubação para as culturas RR deve ser levada em consideração devido à redução da eficiência nutricional imposta pelo glyphosate.The cultivation of soybean-Glycine max (Roundup Ready® - RR has increased and little has been reported on the influence of glyphosate on the nutritional status of the plants. The aim of this work was to compare nutrient accumulation at different phenological stages between the cultivars BRS 184 (conventional and BRS 243 RR (transgenic, with the same crop cycle, under different weed management systems (hand weed and herbicide. Nutrient accumulation and dry matter in conventional soybean was superior to that in the glyphosate-treated RR soybean, indicating that a higher level of nutrients might be required for the RR cultivars to achieve physiological efficiency and a new fertilizer recommendation for RR crops may be considered, due to the reduced nutritional efficiency imposed by glyphosate.

  8. Comportamento da soja RR em distintos ambientes de produção, submetida a diferentes manejos, formulações e doses de glyphosate

    OpenAIRE

    Alfredo Junior Paiola Albrecht

    2014-01-01

    Os benefícios advindos da tecnologia Roundup Ready são expressivos, e a aceitação desta tecnologia pelos produtores rurais é inegável, dando suporte para o rápido crescimento das áreas da soja RR. Mas ao mesmo tempo resultados de pesquisas recentes indicam que o glyphosate aplicado em pós-emergência, em soja RR, pode em algumas situações, além de gerar efeitos fitotóxicos, influenciar o balanço nutricional, afetar a fotossíntese, a rizosfera, o acúmulo de biomassa, a síntese de aminoácidos e ...

  9. Evaluation of corn hybrids expressing Cry1F, cry1A.105, Cry2Ab2, Cry34Ab1/Cry35Ab1, and Cry3Bb1 against southern United States insect pests.

    Science.gov (United States)

    Siebert, M W; Nolting, S P; Hendrix, W; Dhavala, S; Craig, C; Leonard, B R; Stewart, S D; All, J; Musser, F R; Buntin, G D; Samuel, L

    2012-10-01

    Studies were conducted across the southern United States to characterize the efficacy of multiple Bacillus thuringiensis (Bt) events in a field corn, Zea mays L., hybrid for control of common lepidopteran and coleopteran pests. Cry1F protein in event TC1507 and Cry1A.105 + Cry2Ab2 proteins in event MON 89034 were evaluated against pests infesting corn on above-ground plant tissue including foliage, stalks, and ears. Cry34Ab1/Cry35Ab1 proteins in event DAS-59122-7 and Cry3Bb1 in event MON 88017 were evaluated against the larvae of Mexican corn rootworm, Diabrotica virgifera zeae Krysan and Smith, which occur below-ground. Field corn hybrids containing Cry1F, Cry1A.105 + Cry2Ab2, Cry34Ab1/Cry35Ab1, and Cry3Bb1 insecticidal proteins (SmartStax) consistently demonstrated reductions in plant injury and/or reduced larval survivorship as compared with a non-Bt field corn hybrid. Efficacy provided by a field corn hybrid with multiple Bt proteins was statistically equal to or significantly better than corn hybrids containing a single event active against target pests. Single event field corn hybrids provided very high levels of control of southwestern corn borer, Diatraea grandiosella (Dyar), lesser cornstalk borer, Elasmopalpus lignosellus (Zeller), and fall armyworm, Spodoptera frugiperda (J.E. Smith), and were not significantly different than field corn hybrids with multiple events. Significant increases in efficacy were observed for a field corn hybrid with multiple Bt events for sugarcane borer, Diatraea saccharalis (F.), beet armyworm, Spodoptera exigua (Hübner), corn earworm, Helicoverpa zea (Boddie), and Mexican corn rootworm. Utilization of field corn hybrids containing multiple Bt events provides a means for managing insect resistance to Bt proteins and reduces non-Bt corn refuge requirements.

  10. Ab initio modelling of transition metals in diamond

    International Nuclear Information System (INIS)

    Watkins, M; Mainwood, A

    2003-01-01

    Transition metals (TM) from the first transition series are commonly used as solvent catalysts in the synthesis of diamond by high pressure, high temperature processes. Ab initio calculations on these metals, in finite clusters of tetrahedrally coordinated carbon, enable us to investigate trends in their stability and properties. By carrying out systematic studies of interstitial, substitutional and semi-vacancy TM defects, we show that the electronic structure of the TMs is complicated by the presence of 'dangling bonds' when the TM disrupts the crystal lattice: interstitial defects conform to the Ludwig-Woodbury (LW) model, whilst substitutional and semi-vacancy defects move from approximating the LW model early in the transition series to approaching the vacancy model for the heavier metals. Multi-configurational self-consistent field methods allow genuine many-electron states to be modelled; for neutral interstitial, and all substitutional TMs, the crystal fields are found to exceed the exchange energies in strength. Consequently, low spin states are found for these defects. We find substitutional defects to be the most stable, but that semi-vacancy TMs are very similar in energy to the substitutional defects late in the transition series; interstitial defects are only metastable in diamond. Given appropriate charge compensators neutral and positively charged interstitial TM defects were stable, while negatively charged species appeared to be strongly disfavoured

  11. Ab initio transport across bismuth selenide surface barriers

    KAUST Repository

    Narayan, Awadhesh

    2014-11-24

    © 2014 American Physical Society. We investigate the effect of potential barriers in the form of step edges on the scattering properties of Bi2Se3(111) topological surface states by means of large-scale ab initio transport simulations. Our results demonstrate the suppression of perfect backscattering, while all other scattering processes, which do not entail a complete spin and momentum reversal, are allowed. Furthermore, we find that the spin of the surface state develops an out-of-plane component as it traverses the barrier. Our calculations reveal the existence of quasibound states in the vicinity of the surface barriers, which appear in the form of an enhanced density of states in the energy window corresponding to the topological state. For double barriers we demonstrate the formation of quantum well states. To complement our first-principles results we construct a two-dimensional low-energy effective model and illustrate its shortcomings. Our findings are discussed in the context of a number of recent experimental works.

  12. Ab initio prediction of nano-structured materials using supercomputer

    International Nuclear Information System (INIS)

    Kumar, V.; Kawazoe, Y.

    2003-01-01

    Full text: Nano-structured materials are currently attracting great attention due to their promise in future nano-technologies. In the scale of a nanometer, properties of matter are sensitive to the atomic details that are often difficult to obtain from experiments. Impurities could change the properties very significantly. Predictive computer simulations based on ab initio methods are playing a very important role in not only supporting and explaining the experimental findings but also suggesting new possibilities. We shall present a brief overview of the current research done in our group using the supercomputing facilities of the IMR in designing and predicting nano-structured materials. These include the areas of molecular electronics, carbon fullerenes and nanotubes, super-structures on surfaces, multilayers, clusters and nanowires using calculational approaches such as all electron mixed basis, augmented plane wave, localized basis and pseudopotential plane wave methods. More accurate descriptions based on GW and QMC methods are also used. The possibilities of doing large scale calculations are also allowing the study of biological systems such as DNA. We shall discuss in more detail our recent predictions of novel metal encapsulated silicon fullerenes and nanotubes that offer new possibilities in developing silicon based technologies at the nano-scale

  13. Ab Initio Liquid Water Dynamics in Aqueous TMAO Solution.

    Science.gov (United States)

    Usui, Kota; Hunger, Johannes; Sulpizi, Marialore; Ohto, Tatsuhiko; Bonn, Mischa; Nagata, Yuki

    2015-08-20

    Ab initio molecular dynamics (AIMD) simulations in trimethylamine N-oxide (TMAO)-D2O solution are employed to elucidate the effects of TMAO on the reorientational dynamics of D2O molecules. By decomposing the O-D groups of the D2O molecules into specific subensembles, we reveal that water reorientational dynamics are retarded considerably in the vicinity of the hydrophilic TMAO oxygen (O(TMAO)) atom, due to the O-D···O(TMAO) hydrogen-bond. We find that this reorientational motion is governed by two distinct mechanisms: The O-D group rotates (1) after breaking the O-D···O(TMAO) hydrogen-bond, or (2) together with the TMAO molecule while keeping this hydrogen-bond intact. While the orientational slow-down is prominent in the AIMD simulation, simulations based on force field models exhibit much faster dynamics. The simulated angle-resolved radial distribution functions illustrate that the O-D···O(TMAO) hydrogen-bond has a strong directionality through the sp(3) orbital configuration in the AIMD simulation, and this directionality is not properly accounted for in the force field simulation. These results imply that care must be taken when modeling negatively charged oxygen atoms as single point charges; force field models may not adequately describe the hydration configuration and dynamics.

  14. Ab initio calculations of free-energy reaction barriers

    International Nuclear Information System (INIS)

    Bucko, T

    2008-01-01

    The theoretical description of chemical reactions was until recently limited to a 'static' approach in which important parameters such as the rate constant are deduced from the local topology of the potential energy surface close to minima and saddle points. Such an approach has, however, serious limitations. The growing computational power allows us now to use advanced simulation techniques to determine entropic effects accurately for medium-sized systems at ab initio level. Recently, we have implemented free-energy simulation techniques based on molecular dynamics, in particular on the blue-moon ensemble technique and on metadynamics, in the popular DFT code VASP. In the thermodynamic integration (blue-moon ensemble) technique, the free-energy profile is calculated as the path integral over the restoring forces along a parametrized reaction coordinate. In metadynamics, an image of the free-energy surface is constructed on the fly during the simulation by adding small repulsive Gaussian-shaped hills to the Lagrangian driving the dynamics. The two methods are tested on a simple chemical reaction-the nucleophilic substitution of methyl chloride by a chlorine anion

  15. Ab-initio calculations for dilute magnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Belhadji, Brahim

    2008-03-03

    This thesis focusses on ab-initio calculations for the electronic structure and the magnetic properties of dilute magnetic semiconductors (DMS). In particular we aim at the understanding of the complex exchange interactions in these systems. Our calculations are based on density functional theory, being ideally suited for a description of the material specific properties of the considered DMS. Moreover we use the KKR Green function method in connection with the coherent potential approximation (CPA), which allows to include the random substitutional disorder in a mean field-like approximation for the electronic structure. Finally we calculate the exchange coupling constants J{sub ij} between two impurities in a CPA medium by using the Lichtenstein formula and from this calculate the Curie temperature by a numerically exact Monte Carlo method. Based on this analysis we found and investigated four different exchange mechanisms being of importance in DMS systems: Double exchange, p-d exchange, antiferromagnetic superexchanges, and ferromagnetic superexchange. A second topic we have investigated in this thesis is the pressure dependence of the exchange interactions and the Curie temperatures in (Ga,Mn)As and (In,Mn)As, using the LDA and the LDA+U approximations. Exact calculations of T{sub C} by Monte Carlo simulations show a somehow different behavior. (orig.)

  16. Development of materials science by Ab initio powder diffraction analysis

    International Nuclear Information System (INIS)

    Fujii, Kotaro

    2015-01-01

    Crystal structure is most important information to understand properties and behavior of target materials. Technique to analyze unknown crystal structures from powder diffraction data (ab initio powder diffraction analysis) enables us to reveal crystal structures of target materials even we cannot obtain a single crystal. In the present article, three examples are introduced to show the power of this technique in the field of materials sciences. The first example is dehydration/hydration of the pharmaceutically relevant material erythrocycin A. In this example, crystal structures of two anhydrous phases were determined from synchrotron X-ray powder diffraction data and their different dehydration/hydration properties were understood from the crystal structures. In the second example, a crystal structure of a three dimensional metal-organic-framework prepared by a mechanochemical reaction was determined from laboratory X-ray powder diffraction data and the reaction scheme has been revealed. In the third example, a crystal structure of a novel oxide-ion conductor of a new structure family was determined from synchrotron X-ray and neutron powder diffraction data which gave an important information to understand the mechanism of the oxide-ion conduction. (author)

  17. An Ab Initio Based Potential Energy Surface for Water

    Science.gov (United States)

    Partridge, Harry; Schwenke, David W.; Langhoff, Stephen R. (Technical Monitor)

    1996-01-01

    We report a new determination of the water potential energy surface. A high quality ab initio potential energy surface (PES) and dipole moment function of water have been computed. This PES is empirically adjusted to improve the agreement between the computed line positions and those from the HITRAN 92 data base. The adjustment is small, nonetheless including an estimate of core (oxygen 1s) electron correlation greatly improves the agreement with experiment. Of the 27,245 assigned transitions in the HITRAN 92 data base for H2(O-16), the overall root mean square (rms) deviation between the computed and observed line positions is 0.125/cm. However the deviations do not correspond to a normal distribution: 69% of the lines have errors less than 0.05/cm. Overall, the agreement between the line intensities computed in the present work and those contained in the data base is quite good, however there are a significant number of line strengths which differ greatly.

  18. Perovskite transparent conducting oxides: an ab initio study.

    Science.gov (United States)

    Dabaghmanesh, S; Saniz, R; Amini, M N; Lamoen, D; Partoens, B

    2013-10-16

    We present an ab initio study of the electronic structure and of the formation energies of various point defects in BaSnO3 and SrGeO3. We show that La and Y impurities substituting Ba or Sr are shallow donors with a preferred 1 + charge state. These defects have a low formation energy within all the suitable equilibrium growth conditions considered. Oxygen vacancies behave as shallow donors as well, preferring the 2 + charge state. Their formation energies, however, are higher in most growth conditions, indicating a limited contribution to conductivity. The calculated electron effective mass in BaSnO3, with a value of 0.21 m(e), and the very high mobility reported recently in La-doped BaSnO3 single-crystals, suggest that remarkably low scattering rates can be achieved in the latter. In the case of SrGeO3, our results point to carrier density and mobility values in the low range for typical polycrystalline TCOs, in line with experiment.

  19. Accurate ab initio vibrational energies of methyl chloride

    International Nuclear Information System (INIS)

    Owens, Alec; Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter

    2015-01-01

    Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level ab initio theory for the two main isotopologues of methyl chloride, CH 3 35 Cl and CH 3 37 Cl. The respective PESs, CBS-35  HL , and CBS-37  HL , are based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set (CBS) limit, and incorporate a range of higher-level (HL) additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, scalar relativistic effects, and diagonal Born-Oppenheimer corrections. Variational calculations of the vibrational energy levels were performed using the computer program TROVE, whose functionality has been extended to handle molecules of the form XY 3 Z. Fully converged energies were obtained by means of a complete vibrational basis set extrapolation. The CBS-35  HL and CBS-37  HL PESs reproduce the fundamental term values with root-mean-square errors of 0.75 and 1.00 cm −1 , respectively. An analysis of the combined effect of the HL corrections and CBS extrapolation on the vibrational wavenumbers indicates that both are needed to compute accurate theoretical results for methyl chloride. We believe that it would be extremely challenging to go beyond the accuracy currently achieved for CH 3 Cl without empirical refinement of the respective PESs

  20. Accurate ab initio vibrational energies of methyl chloride

    Energy Technology Data Exchange (ETDEWEB)

    Owens, Alec, E-mail: owens@mpi-muelheim.mpg.de [Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany); Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT London (United Kingdom); Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan [Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT London (United Kingdom); Thiel, Walter [Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany)

    2015-06-28

    Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level ab initio theory for the two main isotopologues of methyl chloride, CH{sub 3}{sup 35}Cl and CH{sub 3}{sup 37}Cl. The respective PESs, CBS-35{sup  HL}, and CBS-37{sup  HL}, are based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set (CBS) limit, and incorporate a range of higher-level (HL) additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, scalar relativistic effects, and diagonal Born-Oppenheimer corrections. Variational calculations of the vibrational energy levels were performed using the computer program TROVE, whose functionality has been extended to handle molecules of the form XY {sub 3}Z. Fully converged energies were obtained by means of a complete vibrational basis set extrapolation. The CBS-35{sup  HL} and CBS-37{sup  HL} PESs reproduce the fundamental term values with root-mean-square errors of 0.75 and 1.00 cm{sup −1}, respectively. An analysis of the combined effect of the HL corrections and CBS extrapolation on the vibrational wavenumbers indicates that both are needed to compute accurate theoretical results for methyl chloride. We believe that it would be extremely challenging to go beyond the accuracy currently achieved for CH{sub 3}Cl without empirical refinement of the respective PESs.

  1. Double-walled silicon nanotubes: an ab initio investigation

    Science.gov (United States)

    Lima, Matheus P.

    2018-02-01

    The synthesis of silicon nanotubes realized in the last decade demonstrates multi-walled tubular structures consisting of Si atoms in {{sp}}2 and the {{sp}}3 hybridizations. However, most of the theoretical models were elaborated taking as the starting point {{sp}}2 structures analogous to carbon nanotubes. These structures are unfavorable due to the natural tendency of the Si atoms to undergo {{sp}}3. In this work, through ab initio simulations based on density functional theory, we investigated double-walled silicon nanotubes proposing layered tubes possessing most of the Si atoms in an {{sp}}3 hybridization, and with few {{sp}}2 atoms localized at the outer wall. The lowest-energy structures have metallic behavior. Furthermore, the possibility to tune the band structure with the application of a strain was demonstrated, inducing a metal-semiconductor transition. Thus, the behavior of silicon nanotubes differs significantly from carbon nanotubes, and the main source of the differences is the distortions in the lattice associated with the tendency of Si to make four chemical bonds.

  2. The wonderful complexity of the Mira AB system

    Science.gov (United States)

    Ramstedt, S.; Mohamed, S.; Vlemmings, W. H. T.; Maercker, M.; Montez, R.; Baudry, A.; De Beck, E.; Lindqvist, M.; Olofsson, H.; Humphreys, E. M. L.; Jorissen, A.; Kerschbaum, F.; Mayer, A.; Wittkowski, M.; Cox, N. L. J.; Lagadec, E.; Leal-Ferreira, M. L.; Paladini, C.; Pérez-Sánchez, A.; Sacuto, S.

    2014-10-01

    We have mapped the 12CO(3-2) line emission around the Mira AB system at 0.̋5 resolution using the Atacama Large Millimeter/submillimeter Array (ALMA). The CO map shows amazing complexity. The circumstellar gas has been shaped by different dynamical actors during the evolution of the system, and several morphological components can be identified. The companion is marginally resolved in continuum emission and is currently at 0.̋487 ± 0.̋006 separation. In the main line component, centered on the stellar velocity, spiral arcs around Mira A are found. The spiral appears to be relatively flat and oriented in the orbital plane. An accretion wake behind the companion is clearly visible, and the projected arc separation is about 5''. In the blue wing of the line emission, offset from the main line, several large (~5-10'') opposing arcs are found. We tentatively suggest that this structure is created by the wind of Mira B blowing a bubble in the expanding envelope of Mira A. Appendix A is available in electronic form at http://www.aanda.org

  3. Fatigue Characteristics of 3D Printed Acrylonitrile Butadiene Styrene (ABS)

    Science.gov (United States)

    Padzi, M. M.; Bazin, M. M.; Muhamad, W. M. W.

    2017-11-01

    Recently, the use of 3D printer technology has become significant to industries, especially when involving the new product development. 3D printing is a technology, which produces the 3D product or prototype using a layer-by-layer technique. However, there becomes less research on the mechanical performance of the 3D printed component. In the present work, fatigue characteristics of 3D printed specimen have been studied. Acrylonitrile butadiene styrene (ABS) has been chosen as a material research due to its wide applications. Two types of specimen used, which is the 3D printing and moulding specimens. Fused deposition modelling (FDM) technique was used to produce the specimens. The dog bone shape part was produced based on ASTM D638 standard and the tensile test has been carried out to get the mechanical properties. Fatigue test was carried out at 40%, 60% and 80% of the tensile strength. The moulded part shows higher fatigue cycles compared to 3D printed part for all loading percentages. Fatigue lives for 40%, 60% and 80%, were 911, 2645 and 26948 cycles, respectively. The results indicated that 3D printed part has a lower fatigue life, which may not suitable for industrial applications. However, the 3D printed part could be improved by using various parameters and may be introduced in low strength application.

  4. Ab initio theory of magnetic correlations in itinerant magnets

    International Nuclear Information System (INIS)

    Ling, M.F.

    1997-01-01

    One of the challenging problems in modern magnetism is the description of the paramagnetic state because at finite temperatures the effect of spin fluctuation plays a fundamental role in altering the electronic structure. In magnetic metals, the magnetic properties are linked to the underlying spin-polarised electronic structure in a highly complex manner. In recent years, first-principles electronic structure theories based on the spin density functional (SDF) theory have been able to provide a quantitative account of many ground-state magnetic properties. In this article, the effect of spin fluctuation on the spin-polarised electronic structure and thus the magnetic properties will be discussed and its incorporation into ab initio calculations explained. If the magnetic and compositional ordering energies of magnetic metallic alloys are close, the compositional and magnetic correlations can profoundly influence each other. A theoretical formalism for treating these correlations within the framework of a first-principle electronic structure theory will be elaborated and the application to a number of magnetic alloys discussed and compared with experiments. (author)

  5. Períodos de dessecação de Urochloa ruziziensis e seu reflexo na produtividade da soja RR Burn-down timing of Urochloa ruziziensis and its effect on RR soybean yield

    Directory of Open Access Journals (Sweden)

    M.P. Nepomuceno

    2012-09-01

    Full Text Available Com o objetivo de avaliar os efeitos de períodos de dessecação de Urochloa ruziziensis na implantação e na produtividade da soja transgênica no sistema de plantio direto, foram conduzidos dois experimentos em campo, nos municípios de Colina-SP, no ano agrícola de 2007/08, e Jaboticabal-SP, em 2009/10. Em Colina, utilizou-se uma área de pastagem de U. ruziziensis, conduzida há sete anos. Nesse local foram testados quatro períodos de dessecação da cobertura vegetal: 30, 20, 10 e 0 dias antes da semeadura da soja. No experimento de Jaboticabal, a área utilizada tinha histórico de pastagem com U. ruziziensis, que no ano agrícola 2008/09 foi cultivada com milho. Após a colheita do milho ocorreu reinfestação natural de U. ruziziensis na área, correspondendo a mais de 80% de cobertura vegetal. Nesse experimento, os tratamentos corresponderam a seis períodos de dessecação: 25, 20, 16, 12, 7 e 0 dias após a aplicação. Nos dois experimentos utilizou-se 1,44 kg e.a. ha-1 do herbicida glyphosate e o cultivar de soja M-SOY 7908 RR. O delineamento experimental foi o de blocos ao acaso, com quatro repetições. Foram avaliados o estande da cultura aos 20 dias após a semeadura da soja e na pré-colheita, a altura de plantas, a altura de inserção da primeira vagem, o número de vagens por planta e o rendimento de grãos (produtividade estimada em kg ha-1. Os resultados foram submetidos à análise de variância (teste F, com as médias sendo comparadas pelo teste de Tukey a 5% de probabilidade. A dessecação de U. ruziziensis no mesmo dia da semeadura da soja reduziu a altura das plantas, o número de vagens por planta e a produtividade de grãos. O período recomendado para o manejo químico de U. ruziziensis com glyphosate está entre 10 e 20 dias antes da semeadura da soja. Pôde-se concluir que o período de dessecação de U. ruziziensis alterou a produtividade da cultura.Two field trials were carried out to evaluate the

  6. Effect of oscillatory breathing on the variability of the RR Intervals and its prognostic importance in individuals with left ventricular global systolic dysfunction

    Directory of Open Access Journals (Sweden)

    Barbosa Paulo Roberto Benchimol

    2003-01-01

    Full Text Available OBJECTIVE: To assess the effect of the oscillatory breathing on the variability of RR intervals (VRR and on prognostic significance after one year follow-up in subjects with left ventricular global systolic dysfunction. METHODS: We studied 76 subjects, whose age ranged from 40 to 80 years, paired for age and gender, divided into two groups: group I - 34 healthy subjects; group II - 42 subjects with left ventricular global systolic dysfunction (ejection fraction < 0.40. The ECG signals were acquired during 600s in supine position, and analyzed the variation of the thoracic amplitude and the VRR. Clinical and V-RR variables were applied into a logistic multivariate model to foretell survival after one year follow-up. RESULTS: Oscillatory breathing was detected in 35.7% of subjects in vigil state of group II, with a concentration of the spectral power in the very low frequency band, and was independent of the presence of diabetes, functional class, ejection fraction, cause of ventricular dysfunction and survival after one year follow-up. In the logistic regression model, ejection fraction was the only independent variable to predict survival. CONCLUSION: 1 Oscillatory breathing pattern is frequent during wakefulness in the left ventricular global systolic dysfunction and concentrates spectral power in the very low band of V-RR; 2 it does not relate to severity and cause of left ventricular dysfunction; 3 ejection fraction is the only independent predictive variable for survival in this group of subjects.

  7. Production of R,R-2,3-butanediol of ultra-high optical purity from Paenibacillus polymyxa ZJ-9 using homologous recombination.

    Science.gov (United States)

    Zhang, Li; Cao, Can; Jiang, Ruifan; Xu, Hong; Xue, Feng; Huang, Weiwei; Ni, Hao; Gao, Jian

    2018-04-11

    The present study describes the use of metabolic engineering to achieve the production of R,R-2,3-butanediol (R,R-2,3-BD) of ultra-high optical purity (>99.99%). To this end, the diacetyl reductase (DAR) gene (dud A) of Paenibacillus polymyxa ZJ-9 was knocked out via homologous recombination between the genome and the previously constructed targeting vector pRN5101-L'C in a process based on homologous single-crossover. PCR verification confirmed the successful isolation of the dud A gene disruption mutant P. polymyxa ZJ-9-△dud A. Moreover, fermentation results indicated that the optical purity of R,R-2,3-BD increased from about 98% to over 99.99%, with a titer of 21.62 g/L in Erlenmeyer flasks. The latter was further increased to 25.88 g/L by fed-batch fermentation in a 5-L bioreactor. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Abdominal strengthening using the AbVice machine as measured by surface electromyographic activation levels.

    Science.gov (United States)

    Avedisian, Lori; Kowalsky, Don S; Albro, Richard C; Goldner, Daniel; Gill, Robert C

    2005-08-01

    Twenty-four college students served as subjects in a study that examined the effect of a prototypical abdominal muscle strengthening device (AbVice) compared with other devices currently on the market. The purpose of the present study was to investigate a prototypical device (AbVice) that incorporates contraction of the hamstring and gluteal musculature in conjunction with the abdominals, which may assist in decreasing activation of the hip flexors by allowing greater activity levels of the abdominal musculature via the theory of reflex inhibition, compared with other devices currently available on the market (AbRoller and AbRocker). The repeated-measures study included 17 women and 7 men who ranged in age from 20-23 years (mean +/- SD age, 21.3 +/- 1.5 years). Each subject underwent a single session of data collection during which they completed 10 repetitions of abdominal crunches per device. Subjects completed 4 different crunch sets (AbRocker, AbRoller, standard crunch, AbVice). Counterbalancing of the device was used to negate the effect of fatigue. Speed of repetitions was ensured via use of a metronome set at 40 b.min(-1) to permit similar contraction times and rest periods between repetitions. Rest between conditions was 3 minutes. Mean activation levels of surface electromyography (EMG) were recorded for each condition at the following locations on the right side of the body: rectus abdominis 2.5 cm superior to the umbilicus, rectus abdominis 2.5 cm inferior to the umbilicus, external oblique abdominis 1.0 cm medial to the anterior superior iliac spine, and external oblique abdominis less than 1.0 cm superior to the inguinal ligament. Mean (SD) activation was 1,165.21 mV (634.60 mV) with the AbVice, 242.92 mV (263.03 mV) with the AbRocker, 753.29 mV (514.80 mV) with the standard crunch, and 757.67 mV (542.85 mV) with the AbRoller. Broken down by sex, women had the following mean (SD) EMG values: 1,079.76 mV (705.02 mV) with the AbVice, 680.35 mV (535.35 m

  9. Intermediate steroid withdrawal after renal transplantation and anti-HLA antibodies (HLA-Abs) development.

    Science.gov (United States)

    Monfá, Elena; San Segundo, David; San Millán, Juan Carlos Ruiz; Sanabria, Judith; Albines, Zoila; Rodrigo, Emilio; Romón, Iñigo; Asensio, Esther; Arias, Manuel; López-Hoyos, Marcos

    Steroid withdrawal in renal transplantation is desirable to avoid their adverse effects. However, by decreasing the immunosuppression, could lead to an increased risk for the development of HLA-Abs. Evaluate the relationship between steroid withdrawal and development of HLA-Abs in renal transplantation. We analyzed sera by Luminex from 182 kidney transplants performed from 1998 to 2011, before and two years after transplantation. All the patients had a pretransplant PRA (panel reactive of antibodies) 20%, we detected HLA-Abs pretransplant by Luminex in 11.5% of patients in both groups, of which, 66.6%, versus 53% (p 0.058), developed new specificities, with a similar percentage of donor specific antibodies (DSA) in both groups (33.33% vs 36.36%), pNS. In the subgroup without pretransplant HLA-Abs (group-I; n=115, group-II; n=45), 6.08% developed de novo HLA-Abs, being DSA 3.4% (Group-I) versus 7.69% in group II with 3.84% DSA (pNS). Steroid withdrawal at 7 months of renal transplantation does not entail a higher risk in terms of HLA-Abs development in patients without pretransplant HLA-Abs and treatment with tacrolimus and MMF, although larger studies are needed to confirm these findings. Copyright © 2017 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

  10. High Yield Chemical Vapor Deposition Growth of High Quality Large-Area AB Stacked Bilayer Graphene

    Science.gov (United States)

    Liu, Lixin; Zhou, Hailong; Cheng, Rui; Yu, Woo Jong; Liu, Yuan; Chen, Yu; Shaw, Jonathan; Zhong, Xing; Huang, Yu; Duan, Xiangfeng

    2012-01-01

    Bernal stacked (AB stacked) bilayer graphene is of significant interest for functional electronic and photonic devices due to the feasibility to continuously tune its band gap with a vertical electrical field. Mechanical exfoliation can be used to produce AB stacked bilayer graphene flakes but typically with the sizes limited to a few micrometers. Chemical vapor deposition (CVD) has been recently explored for the synthesis of bilayer graphene but usually with limited coverage and a mixture of AB and randomly stacked structures. Herein we report a rational approach to produce large-area high quality AB stacked bilayer graphene. We show that the self-limiting effect of graphene growth on Cu foil can be broken by using a high H2/CH4 ratio in a low pressure CVD process to enable the continued growth of bilayer graphene. A high temperature and low pressure nucleation step is found to be critical for the formation of bilayer graphene nuclei with high AB stacking ratio. A rational design of a two-step CVD process is developed for the growth of bilayer graphene with high AB stacking ratio (up to 90 %) and high coverage (up to 99 %). The electrical transport studies demonstrated that devices made of the as-grown bilayer graphene exhibit typical characteristics of AB stacked bilayer graphene with the highest carrier mobility exceeding 4,000 cm2/V·s at room temperature, comparable to that of the exfoliated bilayer graphene. PMID:22906199

  11. Characteristics of Cry1Ab Protein from Bioinsecticides and Insect Resistant GM Crops

    Directory of Open Access Journals (Sweden)

    Żmijewska Ewelina

    2016-06-01

    Full Text Available Biological insecticides are an effective method used in plant protection. One of the most widely used active substances in biological insecticides is Cry1Ab protein, which is toxic for lepidopteran insects. This protein is produced during bacterial sporulation by Bacillus thuringiensis. Other sources of Cry1Ab protein are genetically modified plants (GM with expression of cry1Ab gene. Cry1Ab protein in both bioinsecticides and GM plants is present in the form of protoxin, which requires activation by enzymatic treatment in the gut of susceptible insects. So far, Cry1Ab mode of action is not fully understood, but there are 3 main concepts describing it. Two of them assume that a toxic protein after binding to receptors in the insect gut penetrates into the cells, causing pore formation in the gut, which leads to the death of the sensitive insect. In the third model Cry1Ab toxic action is a result of toxin-induced chemical processes initiating a cell death pathway. This work describes the structure and mode of action of Cry1Ab protein, present in biological insecticides and genetically modified plants.

  12. Antibacterial properties of Acinetobacter baumannii phage Abp1 endolysin (PlyAB1).

    Science.gov (United States)

    Huang, Guangtao; Shen, Xiaodong; Gong, Yali; Dong, Zhiwei; Zhao, Xia; Shen, Wei; Wang, Jing; Hu, Fuquan; Peng, Yizhi

    2014-12-12

    Acinetobacter baumannii has emerged as one of the most important hospital-acquired pathogens in the world, because of its resistance to almost all available antibiotic drugs. Endolysins from phages are attracting increasing interest as potential antimicrobial agents, especially for drug-resistant bacteria. We previously isolated and characterized Abp1, a virulent phage targeting the multidrug-resistant A. baumannii strain, AB1. To evaluate the antimicrobial potential of endolysin from the Abp1 phage, the endolysin gene plyAB1 was cloned and over-expressed in Escherichia coli, and the lytic activity of the recombinant protein (PlyAB1) was tested by turbidity assessment and bacteria counting assays. PlyAB1 exhibits a marked lytic activity against A. baumannii AB1, as shown by a decrease in the number of live bacteria following treatment with the enzyme. Moreover, PlyAB1 displayed a highly specific lytic effect against all of the 48 hospital-derived pandrug-resistant A. baumannii isolates that were tested. These isolates were shown to belong to different ST clones by multilocus sequence typing. The results presented here show that PlyAB1 has potential as an antibiotic against drug-resistant A. baumannii.

  13. A comparison of trunk muscle activation: Ab Circle vs. traditional modalities.

    Science.gov (United States)

    Willardson, Jeffrey M; Behm, David G; Huang, Stacey Y; Rehg, Maranda D; Kattenbraker, Mark S; Fontana, Fabio E

    2010-12-01

    The purpose of this study was to compare the activation of the rectus abdominis (RA), external oblique abdominis (EO), lower abdominal stabilizers (LASs), and lumbar erector spinae (LES) during performance of 3 traditional trunk exercises vs. exercise on the Ab Circle device. Surface electromyography was used to assess 12 subjects (6 men, 6 women) for 6 exercise conditions, including: abdominal crunch, side bridge, quadruped, and Ab Circle levels 1-3. For the RA, the abdominal crunch elicited significantly greater activity vs. the Ab Circle level 1, and the side bridge elicited significantly greater activity vs. the Ab Circle levels 1 and 2. For the EO, the side bridge elicited significantly greater activity vs. the quadruped. No significant differences were noted between conditions for the LASs. For the LES, the side bridge and quadruped elicited significantly greater activity vs. the abdominal crunch. The results of this study indicate that the anterior, posterior, and lateral trunk musculature can be activated to similar or even greater levels by performing the 3 traditional trunk exercises vs. the Ab Circle. This was particularly evident for the side bridge exercise, which elicited significantly greater activity of the RA vs. the Ab Circle levels 1 and 2, and elicited similar activity of the EO, LASs, and LES at all 3 Ab Circle levels.

  14. Numerical evaluation of ABS parts fabricated by fused deposition modeling and vapor smoothing

    Directory of Open Access Journals (Sweden)

    Sung-Uk Zhang

    2017-12-01

    Full Text Available The automotive industry has focused to use polymer materials in order to increase energy efficiency. So, the industry pays attention to use 3D printing technologies using several polymers. Among several 3D printer technologies, fused deposition modeling (FDM is one of the popular 3D printing technologies due to an inexpensive extrusion machine and multi-material printing. FDM could use thermoplastics such as ABS, PLA, ULTEM so on. However, it has a problem related to the post-processing because FDM has relatively poor layer resolution. In this study, the mechanical properties of ABS parts fabricated by FDM were measured. The ABS parts were divided into one with vapor smoothing process and the other without the vapor smoothing process which is one of the post-processing methods. Using dynamic mechanical analysis (DMA and dilatometer, temperature-dependent storage modulus and CTE for ABS specimens were measured. Based on the measured thermo-mechanical properties of ABS parts, finite element analysis was performed for an automotive bumper made of ABS. Moreover, response surface methodology was applied to study relationships among design parameters of thickness of the bumper, ambient temperature, and application of the vapor smoothing process. In result, a design guideline for a ABS product could be provided without time-consuming experiments

  15. On The Possible Leakage of ET-RR1 Liquid Waste Tank: Hydrological and Migration Modes Studies

    Directory of Open Access Journals (Sweden)

    N. S. Mahmoud

    2005-01-01

    Full Text Available The first Egyptian (ET-RR1 research reactor has been in operation since 1961 at the Egyptian Atomic Energy Authority (EAEA Inshas site. Therefore, at present, it faces a serious problem due to aging equipment, especially those directly in contact with the environment such as the underground settling tanks of nuclear and radioactive waste. The possible leakage of radionuclides from these aging tanks and their migration to the aquifer was studied using instantaneous release.This study was done based on the geological and hydrological characteristics of the site, which were obtained from the hydrogeological data of 25 wells previously drilled at the site of the reactor[1]. These data were used to calculate the trend of water levels, hydraulic gradient, and formulation of water table maps from 1993–2002. This information was utilized to determine water velocity in the unsaturated zone.Radionuclides released from the settling tank to the aquifer were screened according to the radionuclides that have high migration ability and high activity. The amount of fission and activation products of the burned fuels that contaminated the water content of the reactor pool were considered as 10% of the original spent fuel. The radionuclides considered in this case were H-3, Sr-90, Zr-93, Tc-99, Cd-113, Cs-135, Cs-137, Sm-151, Pu-238, Pu-240, Pu-241, and Am-241.The instantaneous release was analyzed by theoretical calculations, taking into consideration the migration mechanism of the various radionuclides through the soil space between the tank bottom and the aquifer. The migration mechanism through the unsaturated zone was considered depending on soil type, thickness of the unsaturated zone, water velocity, and other factors that are specific for each radionuclide, namely retardation factor, which is the function of the specific distribution coefficient of each radionuclide. This was considered collectively as delay time. Meanwhile, the mechanism of

  16. 40 CFR 174.529 - Bacillus thuringiensis modified Cry1Ab protein as identified under OECD Unique Identifier SYN...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Bacillus thuringiensis modified Cry1Ab... Tolerance Exemptions § 174.529 Bacillus thuringiensis modified Cry1Ab protein as identified under OECD... Bacillus thuringiensis modified Cry1Ab protein as identified under OECD Unique Identifier SYN-IR67B-1 are...

  17. Cationization increases brain distribution of an amyloid-beta protofibril selective F(ab')2 fragment

    OpenAIRE

    Syvänen, Stina; Edén, Desireé; Sehlin, Dag

    2017-01-01

    Antibodies and fragments thereof are, because of high selectivity for their targets, considered as potential therapeutics and biomarkers for several neurological disorders. However, due to their large molecular size, antibodies/fragments do not easily penetrate into the brain. The aim of the present study was to improve the brain distribution via adsorptive-mediated transcytosis of an amyloid-beta (A beta) protofibril selective F(ab')2 fragment (F(ab')2-h158). F(ab')2-h158 was cationized to d...

  18. Hydrothermal Synthesis of Bi2S3 Nanostructures and ABS-Based Polymeric Nanocomposite

    Directory of Open Access Journals (Sweden)

    D. Ghanbari

    2014-04-01

    Full Text Available Bismuth sulfide nano-rods and nano-flowers were synthesized via a hydrothermal reaction at a relatively low temperature. Thioglycolic acid is used as sulfur source and capping agent simultaneously. Bi2S3 nanostructures were then added to acrylonitrile-butadiene-styrene (ABS copolymer. The thermal stability behavior of ABS filled with bismuth sulfide nano-rods were investigated by thermogravimetric analysis (TGA. Nanostructures were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and atomic force microscopy (AFM. The flame retardancy behavior of ABS-Bi2S3 was studied by UL-94 analysis.

  19. Hospital antibiotic management in Hungary--results of the ABS maturity survey of the ABS International group.

    Science.gov (United States)

    Ternak, Gabor; Almasi, Istvan; Rakoczi, Eva

    2008-01-01

    The prudent use of antibiotics is considered a very important issue in hospitals throughout Europe. The project ABS International developed a questionnaire to survey antibiotic-related structures and services in the hospitals of participating countries. This article describes the situation in Hungary. Questionnaires were sent to all the hospitals in Hungary, which numbered 182 at the time of the survey. A total of 68 hospitals, accounting for 37.4% of all hospitals, returned the answered questionnaires. These 68 hospitals accounted for 52.4% of the hospital beds available in Hungary at the time of the survey. The answers were stratified according to the function and position of the hospitals and analyzed by calculating means, medians and standard deviations of various parameters. The cumulative maturity figure for Hungary was 3.42+/-0.55. The lowest cumulative figures were found in chronic-care hospitals and the highest in the university hospitals. Significant differences were found in the availability of diagnostic services. The level of control of antibiotic consumption was similar between hospitals. The availability of bedside microbiological tests, such as legionella antigen detection, was rated as poor. Resources dedicated for antibiotic officers were very minor. Antibiotic stewardship cannot be conducted without appropriate resources (time, financing) provided by hospital management or the authorities. The technical background (microbiology, organizations, etc.) on which to build is already available in Hungarian hospitals.

  20. Hospital antibiotic management in Slovenia--results of the ABS maturity survey of the ABS International group.

    Science.gov (United States)

    Cizman, Milan; Bajec, Tom; Sibanc, Branko; Pal, Emil; Gorisek, Jelka Rebersek; Remec, Tatjana; Stefancic, Metka; Martincic, Tatjana; Najdenov, Brigita; Strancar, Katja; Salemovic, Danilo; Bogovic, Metka; Ovnic, Alenka

    2008-01-01

    The ever-increasing resistance to antibiotics is a serious worldwide problem. Antibiotic strategies for appropriate use of antimicrobials in hospitals are not well defined. A questionnaire on "ABS maturity of hospitals" was the basis of an analysis as a part of an EU project. This questionnaire was sent to 12 hospitals in Slovenia including 11 general hospitals and one university hospital. All 12 hospitals returned the questionnaires. Maturity of antibiotic strategies were considered moderate (3.74). Antibiotic consumption had the highest maturity ratio (4.44), followed by diagnostics (3.96), antibiotic-related relationships (3.58), antibiotic-related personnel development (3.44) and antibiotic-related organization (3.36). The availability of data on antibiotic consumption had the highest ranking; designation of and time resources for antibiotic officers were ranked lowest. In Slovenia the maturity of antibiotic strategies in general hospitals and in one university hospital is moderate. The data provide a basis for further development of antibiotic-related issues in hospitals.

  1. Higher dimensional homogeneous cosmology in Lyra geometry

    Indian Academy of Sciences (India)

    is argued that the extra dimensions are observable at the present time, owing to their size being assumed to be of ... While attempting to unify gravitation and electromagnetism in a single space-time ge- ometry, Weyl [4] showed .... From eqs (25), (26) and (9) we obtain, after some mathematical manipulation, a first inte- gral.

  2. Efficient conformational space exploration in ab initio protein folding simulation.

    Science.gov (United States)

    Ullah, Ahammed; Ahmed, Nasif; Pappu, Subrata Dey; Shatabda, Swakkhar; Ullah, A Z M Dayem; Rahman, M Sohel

    2015-08-01

    Ab initio protein folding simulation largely depends on knowledge-based energy functions that are derived from known protein structures using statistical methods. These knowledge-based energy functions provide us with a good approximation of real protein energetics. However, these energy functions are not very informative for search algorithms and fail to distinguish the types of amino acid interactions that contribute largely to the energy function from those that do not. As a result, search algorithms frequently get trapped into the local minima. On the other hand, the hydrophobic-polar (HP) model considers hydrophobic interactions only. The simplified nature of HP energy function makes it limited only to a low-resolution model. In this paper, we present a strategy to derive a non-uniform scaled version of the real 20×20 pairwise energy function. The non-uniform scaling helps tackle the difficulty faced by a real energy function, whereas the integration of 20×20 pairwise information overcomes the limitations faced by the HP energy function. Here, we have applied a derived energy function with a genetic algorithm on discrete lattices. On a standard set of benchmark protein sequences, our approach significantly outperforms the state-of-the-art methods for similar models. Our approach has been able to explore regions of the conformational space which all the previous methods have failed to explore. Effectiveness of the derived energy function is presented by showing qualitative differences and similarities of the sampled structures to the native structures. Number of objective function evaluation in a single run of the algorithm is used as a comparison metric to demonstrate efficiency.

  3. Machine Learning Force Field Parameters from Ab Initio Data

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ying [Argonne; Li, Hui [Department; Pickard, Frank C. [Laboratory; Narayanan, Badri [Center; Sen, Fatih G. [Center; Chan, Maria K. Y. [Center; Computational; Sankaranarayanan, Subramanian K. R. S. [Center; Computational; Brooks, Bernard R. [Laboratory; Roux, Benoît [Department; Center; Computational

    2017-08-11

    Machine learning (ML) techniques with the genetic algorithm (GA) have been applied to determine a polarizable force field parameters using only ab initio data from quantum mechanics (QM) calculations of molecular clusters at the MP2/6-31G(d,p), DFMP2(fc)/jul-cc-pVDZ, and DFMP2(fc)/jul-cc-pVTZ levels to predict experimental condensed phase properties (i.e., density and heat of vaporization). The performance of this ML/GA approach is demonstrated on 4943 dimer electrostatic potentials and 1250 cluster interaction energies for methanol. Excellent agreement between the training data set from QM calculations and the optimized force field model was achieved. The results were further improved by introducing an offset factor during the machine learning process to compensate for the discrepancy between the QM calculated energy and the energy reproduced by optimized force field, while maintaining the local “shape” of the QM energy surface. Throughout the machine learning process, experimental observables were not involved in the objective function, but were only used for model validation. The best model, optimized from the QM data at the DFMP2(fc)/jul-cc-pVTZ level, appears to perform even better than the original AMOEBA force field (amoeba09.prm), which was optimized empirically to match liquid properties. The present effort shows the possibility of using machine learning techniques to develop descriptive polarizable force field using only QM data. The ML/GA strategy to optimize force fields parameters described here could easily be extended to other molecular systems.

  4. Cosmic-ray modulation: an ab initio approach

    International Nuclear Information System (INIS)

    Engelbrecht, N.E.; Burger, R.A.

    2014-01-01

    A better understanding of cosmic-ray modulation in the heliosphere can only be gained through a proper understanding of the effects of turbulence on the diffusion and drift of cosmic rays. We present an ab initio model for cosmic-ray modulation, incorporating for the first time the results yielded by a two-component turbulence transport model. This model is solved for periods of minimum solar activity, utilizing boundary values chosen so that model results are in fair to good agreement with spacecraft observations of turbulence quantities, not only in the solar ecliptic plane but also along the out-of-ecliptic trajectory of the Ulysses spacecraft. These results are employed as inputs for modelled slab and 2D turbulence energy spectra. The latter spectrum is chosen based on physical considerations, with a drop-off at the very lowest wavenumbers commencing at the 2D outerscale. There currently exist no models or observations for this quantity, and it is the only free parameter in this study. The modelled turbulence spectra are used as inputs for parallel mean free path expressions based on those derived from quasi-linear theory and perpendicular mean free paths from extended nonlinear guiding center theory. Furthermore, the effects of turbulence on cosmic-ray drifts are modelled in a self-consistent way, employing a recently developed model for drift along the wavy current sheet. The resulting diffusion coefficients and drift expressions are applied to the study of galactic cosmic-ray protons and antiprotons using a three dimensional, steady-state cosmic-ray modulation code, and sample solutions in fair agreement with multiple spacecraft observations are presented. (author)

  5. Cosmic-ray modulation: an ab initio approach

    Energy Technology Data Exchange (ETDEWEB)

    Engelbrecht, N.E.; Burger, R.A., E-mail: 12580996@nwu.ac.za [Center for Space Research, North-West University, Potchefstroom (South Africa)

    2014-07-01

    A better understanding of cosmic-ray modulation in the heliosphere can only be gained through a proper understanding of the effects of turbulence on the diffusion and drift of cosmic rays. We present an ab initio model for cosmic-ray modulation, incorporating for the first time the results yielded by a two-component turbulence transport model. This model is solved for periods of minimum solar activity, utilizing boundary values chosen so that model results are in fair to good agreement with spacecraft observations of turbulence quantities, not only in the solar ecliptic plane but also along the out-of-ecliptic trajectory of the Ulysses spacecraft. These results are employed as inputs for modelled slab and 2D turbulence energy spectra. The latter spectrum is chosen based on physical considerations, with a drop-off at the very lowest wavenumbers commencing at the 2D outerscale. There currently exist no models or observations for this quantity, and it is the only free parameter in this study. The modelled turbulence spectra are used as inputs for parallel mean free path expressions based on those derived from quasi-linear theory and perpendicular mean free paths from extended nonlinear guiding center theory. Furthermore, the effects of turbulence on cosmic-ray drifts are modelled in a self-consistent way, employing a recently developed model for drift along the wavy current sheet. The resulting diffusion coefficients and drift expressions are applied to the study of galactic cosmic-ray protons and antiprotons using a three dimensional, steady-state cosmic-ray modulation code, and sample solutions in fair agreement with multiple spacecraft observations are presented. (author)

  6. AN AB INITIO MODEL FOR COSMIC-RAY MODULATION

    Energy Technology Data Exchange (ETDEWEB)

    Engelbrecht, N. E.; Burger, R. A. [Center for Space Research, North-West University, Potchefstroom 2520 (South Africa)

    2013-07-20

    A proper understanding of the effects of turbulence on the diffusion and drift of cosmic rays (CRs) is of vital importance for a better understanding of CR modulation in the heliosphere. This study presents an ab initio model for CR modulation, incorporating for the first time the results yielded by a two-component turbulence transport model. This model is solved for solar minimum heliospheric conditions, utilizing boundary values chosen so that model results are in reasonable agreement with spacecraft observations of turbulence quantities in the solar ecliptic plane and along the out-of-ecliptic trajectory of the Ulysses spacecraft. These results are employed as inputs for modeled slab and two-dimensional (2D) turbulence energy spectra. The modeled 2D spectrum is chosen based on physical considerations, with a drop-off at the very lowest wavenumbers. There currently exist no models or observations for the wavenumber where this drop-off occurs, and it is considered to be the only free parameter in this study. The modeled spectra are used as inputs for parallel mean free path expressions based on those derived from quasi-linear theory and perpendicular mean free paths from extended nonlinear guiding center theory. Furthermore, the effects of turbulence on CR drifts are modeled in a self-consistent way, also employing a recently developed model for wavy current sheet drift. The resulting diffusion and drift coefficients are applied to the study of galactic CR protons and antiprotons using a 3D, steady-state CR modulation code, and sample solutions in fair to good agreement with multiple spacecraft observations are presented.

  7. Lithium Insertion In Silicon Nanowires: An ab Initio Study

    KAUST Repository

    Zhang, Qianfan

    2010-09-08

    The ultrahigh specific lithium ion storage capacity of Si nanowires (SiNWs) has been demonstrated recently and has opened up exciting opportunities for energy storage. However, a systematic theoretical study on lithium insertion in SiNWs remains a challenge, and as a result, understanding of the fundamental interaction and microscopic dynamics during lithium insertion is still lacking. This paper focuses on the study of single Li atom insertion into SiNWs with different sizes and axis orientations by using full ab initio calculations. We show that the binding energy of interstitial Li increases as the SiNW diameter grows. The binding energies at different insertion sites, which can be classified as surface, intermediate, and core sites, are quite different. We find that surface sites are energetically the most favorable insertion positions and that intermediate sites are the most unfavorable insertion positions. Compared with the other growth directions, the [110] SiNWs with different diameters always present the highest binding energies on various insertion locations, which indicates that [110] SiNWs are more favorable by Li doping. Furthermore, we study Li diffusion inside SiNWs. The results show that the Li surface diffusion has a much higher chance to occur than the surface to core diffusion, which is consistent with the experimental observation that the Li insertion in SiNWs is layer by layer from surface to inner region. After overcoming a large barrier crossing surface-to-intermediate region, the diffusion toward center has a higher possibility to occur than the inverse process. © 2010 American Chemical Society.

  8. Adjuvant Ab Interno Tumor Treatment After Proton Beam Irradiation.

    Science.gov (United States)

    Seibel, Ira; Riechardt, Aline I; Heufelder, Jens; Cordini, Dino; Joussen, Antonia M

    2017-06-01

    This study was performed to show long-term outcomes concerning globe preservation in uveal melanoma patients after proton beam therapy with the main focus on outcomes according to different adjuvant ab interno surgical procedures. Retrospective cohort study. All patients treated with primary proton beam therapy for choroidal or ciliary body melanoma between June 1998 and June 2015 were included. A total of 2499 patients underwent primary proton beam therapy, with local tumor control and globe preservation rates of 95.9% and 94.8% after 5 years, respectively. A total of 110 (4.4%) patients required secondary enucleation. Unresponsive neovascular glaucoma was the leading cause of secondary enucleation in 78 of the 2499 patients (3.1%). The 5-year enucleation-free survival rate was 94.8% in the endoresection group, 94.3% in the endodrainage group, and 93.5% in the comparator group. The log-rank test showed P = .014 (comparator group vs endoresection group) and P = .06 (comparator group vs endodrainage-vitrectomy group). Patients treated with endoresection or endodrainage-vitrectomy developed less radiation retinopathy (30.5% and 37.4% after 5 years, P = .001 and P = .048 [Kaplan-Meier], respectively) and less neovascular glaucoma (11.6% and 21.3% after 5 years, P = .001 and P = .01 [Kaplan-Meier], respectively) compared with the comparator group (52.3% radiation retinopathy and 57.8% neovascular glaucoma after 5 years). This study suggests that in larger tumors the enucleation and neovascular glaucoma rates might be reduced by adjuvant surgical procedures. Although endoresection is the most promising adjuvant treatment option, the endodrainage-vitrectomy is recommended in patients who are ineligible for endoresection. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. TH-AB-BRB-02: ET-Reloaded

    International Nuclear Information System (INIS)

    Wu, Q.

    2016-01-01

    CA183390, NIH R01CA188300, Varian Medical Systems V. Yu, Varian Medical Systems, AAPM Summer Undergraduate Fellowship, NSF graduate fellowship S. Nill, Elekta AB. Cancer Research UK under Programme C33589/A19727, NIHR Biomedical Research Centre at The Royal Marsden and The Institute of Cancer Research.

  10. TH-AB-BRB-03: 4n Radiotherapy

    International Nuclear Information System (INIS)

    Sheng, K.

    2016-01-01

    CA183390, NIH R01CA188300, Varian Medical Systems V. Yu, Varian Medical Systems, AAPM Summer Undergraduate Fellowship, NSF graduate fellowship S. Nill, Elekta AB. Cancer Research UK under Programme C33589/A19727, NIHR Biomedical Research Centre at The Royal Marsden and The Institute of Cancer Research.

  11. Optical properties of highly compressed polystyrene: An ab initio study

    Science.gov (United States)

    Hu, S. X.; Collins, L. A.; Colgan, J. P.; Goncharov, V. N.; Kilcrease, D. P.

    2017-10-01

    Using all-electron density functional theory, we have performed an ab initio study on x-ray absorption spectra of highly compressed polystyrene (CH). We found that the K -edge shifts in strongly coupled, degenerate polystyrene cannot be explained by existing continuum-lowering models adopted in traditional plasma physics. To gain insights into the K -edge shift in warm, dense CH, we have developed a model designated as "single mixture in a box" (SMIAB), which incorporates both the lowering of the continuum and the rising of the Fermi surface resulting from high compression. This simple SMIAB model correctly predicts the K -edge shift of carbon in highly compressed CH in good agreement with results from quantum molecular dynamics (QMD) calculations. Traditional opacity models failed to give the proper K -edge shifts as the CH density increased. Based on QMD calculations, we have established a first-principles opacity table (FPOT) for CH in a wide range of densities and temperatures [ρ =0.1 -100 g /c m3 and T =2000 -1 000 000 K ]. The FPOT gives much higher Rosseland mean opacity compared to the cold-opacity-patched astrophysics opacity table for warm, dense CH and favorably compares to the newly improved Los Alamos atomic model for moderately compressed CH (ρCH≤10 g /c m3 ), but remains a factor of 2 to 3 higher at extremely high densities (ρCH≥50 g /c m3 ). We anticipate the established FPOT of CH will find important applications to reliable designs of high-energy-density experiments. Moreover, the understanding of K -edge shifting revealed in this study could provide guides for improving the traditional opacity models to properly handle the strongly coupled and degenerate conditions.

  12. Rapid Solidification of AB{sub 5} Hydrogen Storage Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gulbrandsen-Dahl, Sverre

    2002-01-01

    This doctoral thesis is concerned with rapid solidification of AB{sub 5} materials suitable for electrochemical hydrogen storage. The primary objective of the work has been to characterise the microstructure and crystal structure of the produced AB{sub 5} materials as a function of the process parameters, e.g. the cooling rate during rapid solidification, the determination of which has been paid special attention to. The thesis is divided into 6 parts, of which Part I is a literature review, starting with a short presentation of energy storage alternatives. Then a general review of metal hydrides and their utilisation as energy carriers is presented. This part also includes more detailed descriptions of the crystal structure, the chemical composition and the hydrogen storage properties of AB{sub 5} materials. Furthermore, a description of the chill-block melt spinning process and the gas atomisation process is given. In Part II of the thesis a digital photo calorimetric technique has been developed and applied for obtaining in situ temperature measurements during chill-block melt spinning of a Mm(NiCoMnA1){sub 5} hydride forming alloy (Mm = Mischmetal of rare earths). Compared with conventional colour transmission temperature measurements, this technique offers a special advantage in terms of a high temperature resolutional and positional accuracy, which under the prevailing experimental conditions were found to be {+-}29 K and {+-} 0.1 mm, respectively. Moreover, it is shown that the cooling rate in solid state is approximately 2.5 times higher than that observed during solidification, indicating that the solid ribbon stayed in intimate contact with the wheel surface down to very low metal temperatures before the bond was broken. During this contact period the cooling regime shifted from near ideal in the melt puddle to near Newtonian towards the end, when the heat transfer from the solid ribbon to the wheel became the rate controlling step. In Part III of the

  13. A cross-metathesis approach to the stereocontrolled synthesis of the AB ring segment of ciguatoxin

    OpenAIRE

    Kadota, Isao; Abe, Takashi; Uni, Miyuki; Takamura, Hiroyoshi; Yamamoto, Yoshinori

    2008-01-01

    Synthesis of the AB ring segments of ciguatoxin is described. The present synthesis includes a Lewis acid mediated cyclization of allylstannane with aldehyde, cross-metathesis reaction introducing the side chain, and Grieco-Nishizawa dehydration on the A ring.

  14. Ab initio Molecular Orbital Studies of the Vibrational Spectra of some ...

    African Journals Online (AJOL)

    Ab initio Molecular Orbital Studies of the Vibrational Spectra of some van der Waals Complexes. Part 4. Complexes of Sulphur Dioxide with Carbon Dioxide, Carbonyl Sulphide, Carbon Disulphide and Nitrous Oxide.

  15. Domino Wittig Diels-Alder reaction: An expeditious entry into the AB ring system of furanosesquiterpenes

    Digital Repository Service at National Institute of Oceanography (India)

    Patre, R.E.; Gawas, S.; Sen, S.; Parameswaran, P.S.; Tilve, S.G.

    A domino Wittig Diels - Alder reaction has been employed in delineating a short and flexible synthetic stratagem for ready access to the AB ring system and the tricyclic framework of furanosesquiterpenes, such as the bioactive natural products...

  16. The end of a myth – Bt (Cry1Ab maize does not harm green lacewings

    Directory of Open Access Journals (Sweden)

    Joerg eRomeis

    2014-08-01

    Full Text Available A concern with Bt-transgenic insect-resistant plants is their potential to harm non-target organisms. Early studies reported that Cry1Ab-producing Bt maize and purified Cry1Ab harmed larvae of the green lacewing, Chrysoperla carnea. Although these effects could not be confirmed in subsequent studies, some authors still refer to them as evidence that Bt maize harms beneficial species. We provide a comprehensive review of the studies evaluating the effects of Bt (Cry1Ab maize on C. carnea. The evidence indicates that this important predator is not affected by Bt maize or by the produced Cry1Ab protein. We discuss how conceptual models can assist environmental risk assessments, and we emphasize the importance of robust and reproducible studies.

  17. The end of a myth-Bt (Cry1Ab) maize does not harm green lacewings.

    Science.gov (United States)

    Romeis, Jörg; Meissle, Michael; Naranjo, Steven E; Li, Yunhe; Bigler, Franz

    2014-01-01

    A concern with Bt-transgenic insect-resistant plants is their potential to harm non-target organisms. Early studies reported that Cry1Ab-producing Bt maize and purified Cry1Ab harmed larvae of the green lacewing, Chrysoperla carnea. Although these effects could not be confirmed in subsequent studies, some authors still refer to them as evidence that Bt maize harms beneficial species. We provide a comprehensive review of the studies evaluating the effects of Bt (Cry1Ab) maize on C. carnea. The evidence indicates that this important predator is not affected by Bt maize or by the produced Cry1Ab protein. We discuss how conceptual models can assist environmental risk assessments, and we emphasize the importance of robust and reproducible studies.

  18. The end of a myth—Bt (Cry1Ab) maize does not harm green lacewings

    Science.gov (United States)

    Romeis, Jörg; Meissle, Michael; Naranjo, Steven E.; Li, Yunhe; Bigler, Franz

    2014-01-01

    A concern with Bt-transgenic insect-resistant plants is their potential to harm non-target organisms. Early studies reported that Cry1Ab-producing Bt maize and purified Cry1Ab harmed larvae of the green lacewing, Chrysoperla carnea. Although these effects could not be confirmed in subsequent studies, some authors still refer to them as evidence that Bt maize harms beneficial species. We provide a comprehensive review of the studies evaluating the effects of Bt (Cry1Ab) maize on C. carnea. The evidence indicates that this important predator is not affected by Bt maize or by the produced Cry1Ab protein. We discuss how conceptual models can assist environmental risk assessments, and we emphasize the importance of robust and reproducible studies. PMID:25161661

  19. Remodeling of the AB site of rat parvalbumin and oncomodulin into a canonical EF-hand

    DEFF Research Database (Denmark)

    Cox, J A; Durussel, I; Scott, D J

    1999-01-01

    Parvalbumin (PV) and the homologous protein oncomodulin (OM) contain three EF-hand motifs, but the first site (AB) cannot bind Ca2+. Here we aimed to recreate the putative ancestral proteins [D19-28E]PV and [D19-28E]OM by replacing the 10-residue-long nonfunctional loop in the AB site by a 12...... fluorescence. The metal-free oncomodulins are partially unfolded and seem not to possess a hydrophobic core. Our data indicate that AB-remodeled parvalbumin has the potential to regulate cell functions, whereas it is unlikely that [D19-28E]OM can play a regulatory role in vivo. The predicted evolution...... of the AB site from a canonical to an abortive EF-hand may have been dictated by the need for stronger interaction with Mg2+ and Ca2+, and a high conformational stability of the metal-free forms....

  20. Ab initio study of gas phase and water-assisted tautomerization of ...

    Indian Academy of Sciences (India)

    WINTEC

    Ab initio study of gas phase and water-assisted tautomerization of maleimide and formamide. 623. Figure 4. Keto to enol conversion of (a) maleimide and (b) formamide in gas phase. (c) maleimide and (d) forma- mide with water.

  1. Application of Cry1Ab/Ac Bt strip for screening of resistance for ...

    African Journals Online (AJOL)

    ABU ZAYD

    2013-10-02

    Envirologix, 2008). ... gene, while the appearance of only the top (control) line indicates a negative response. Cry1Ab gene .... gene was found to be in Mendelian fashion in all the six cowpea crosses, the results indicate.

  2. Isolation and Characterization of a Virulent Bacteriophage AB1 of Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Jia Shiru

    2010-04-01

    Full Text Available Abstract Background Acinetobacter baumannii is an emerging nosocomial pathogen worldwide with increasing prevalence of multi-drug and pan-drug resistance. A. baumannii exists widely in natural environment, especially in health care settings, and has been shown difficult to be eradicated. Bacteriophages are often considered alternative agent for controlling bacterial infection and contamination. In this study, we described the isolation and characterization of one virulent bacteriophage AB1 capable of specifically infecting A. baumannii. Results A virulent bacteriophage AB1, specific for infecting a clinical strain A. baumannii KD311, was first isolated from marine sediment sample. Restriction analysis indicated that phage AB1 was a dsDNA virus with an approximate genome size of 45.2 kb to 46.9 kb. Transmission electron microscopy showed that phage AB1 had an icosahedral head with a non-contractile tail and collar or whisker structures, and might be tentatively classified as a member of the Siphoviridae family. Proteomic pattern of phage AB1, generated by SDS-PAGE using purified phage particles, revealed five major bands and six minor bands with molecular weight ranging from 14 to 80 kilo-dalton. Also determined was the adsorption rate of phage AB1 to the host bacterium, which was significantly enhanced by addition of 10 mM CaCl2. In a single step growth test, phage AB1 was shown having a latent period of 18 minutes and a burst size of 409. Moreover, pH and thermal stability of phage AB1 were also investigated. At the optimal pH 6.0, 73.2% of phages survived after 60 min incubation at 50°C. When phage AB1 was used to infect four additional clinical isolates of A. baumannii, one clinical isolate of Stenotrophomonas maltophilia, and Pseudomonas aeruginosa lab strains PAK and PAO1, none of the tested strains was found susceptible, indicating a relatively narrow host range for phage AB1. Conclusion Phage AB1 was capable of eliciting efficient lysis

  3. Structural Nonrigitidy of Nucleid Acid Bases. Post-Hartree-Fock ab initio Study

    Czech Academy of Sciences Publication Activity Database

    Shishkin, O. V.; Gorb, L.; Hobza, Pavel; Leszczynski, J.

    2000-01-01

    Roč. 80, 4/5 (2000), s. 1116-1124 ISSN 0020-7608 Grant - others:NSF(US) 94-4-756-01; NIH(US) G12RR13459 Institutional research plan: CEZ:AV0Z4040901 Keywords : uracyl * thymine * isocytosine guanine and adenine Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.317, year: 2000

  4. Radioiodine Labeled Anti-MIF McAb: A Potential Agent for Inflammation Imaging

    Directory of Open Access Journals (Sweden)

    Chao Zhang

    2007-01-01

    Full Text Available Macrophage migration inhibitory factor (MIF is a proinflammatory cytokine that may play a role in the pathogenesis of inflammation. Radiolabeled anti-MIF McAb can be used to detect in vivo inflammatory changes. The objective of this study was to investigate in vivo biology of radioiodinated anti-MIF McAb using the inflammation model mice. Anti-MIF McAb was radioiodinated with NaI125 by Iodogen method. Animal models were induced in the mice by intramuscular injection of S. aureus, E. coli, and turpentine oil. The biodistribution studies with radioiodinated anti-MIF McAb were performed on inflammation mice. The relationship between inflammatory lesions and anti-MIF McAb binding was investigated using the percent of injected dose per gram tissue (% ID/g of tissue samples and whole-body autoradiography. The radioactivity of I125-anti-MIF McAb in the inflammatory tissue increased gradually for three inflammation models. The highest uptake was found in S. aureus group and the lowest was in E. coli group. The uptake in turpentine oil group was average. Whole-body autoradiography showed that all inflammation foci could be visualized clearly from 24 hours after injection, but 48 hours images were much clearer in accordance with the high T/NT ratio. These results demonstrate the ability of radioiodinated anti-MIF McAb to measure in vivo inflammatory events represented by high expression of MIF and suggests that radiolabeled anti-MIF McAb warrants further investigation as a potential inflammation-seeking agent for imaging to detect inflammatory disorders.

  5. URHEILUN SPONSOROINTI JA LUMILAUTAILU : FOREX Bank Ab:n mahdollisuudet lumilautailun sponsorointiin

    OpenAIRE

    Autio, Suvi

    2011-01-01

    FOREX Bank Ab on Pohjoismaiden suurin valuutanvaihtoon erikoistunut yritys. FOREXin liikeideana on tarjota maasta lähteville ja maahan saapuville matkailijoille valuuttaa joustaviin kellonaikoihin, keskeisillä paikoilla, sekä kilpailukykyisillä kursseilla ja toimitusmaksuilla. Opinnäytetyön aiheena oli urheilun sponsorointi ja lumilautailu. Opinnäytetyön tarkoituksena oli selvittää FOREX Bank Ab:n sponsoroinnin nykytilaa ja lumilautailun sopivuutta FOREXin sponsorointikohteeksi. Teoriaosu...

  6. Ab initio Quantum Chemical and Experimental Reaction Kinetics Studies in the Combustion of Bipropellants

    Science.gov (United States)

    2017-03-24

    NUMBER (Include area code) 24 March 2017 Briefing Charts 01 March 2017 - 31 March 2017 Ab initio Quantum Chemical and Experimental Reaction Kinetics...Laboratory AFRL/RQRS 1 Ara Road Edwards AFB, CA 93524 *Email: ghanshyam.vaghjiani@us.af.mil Ab initio Quantum Chemical and Experimental Reaction ...Clearance 17161 Zador et al., Prog. Energ. Combust. Sci., 37 371 (2011) Why Quantum Chemical Reaction Kinetics Studies? DISTRIBUTION A: Approved for

  7. An ab initio study of plutonium oxides surfaces; Etude ab initio des surfaces d'oxydes de Pu

    Energy Technology Data Exchange (ETDEWEB)

    Jomard, G.; Bottin, F.; Amadon, B

    2007-07-01

    By means of first-principles calculations, we have studied the atomic structure as well as the thermodynamic stability of various plutonium dioxide surfaces in function of their environment (in terms of oxygen partial pressure and temperature). All these simulations have been performed with the ABINIT code. It is well known that DFT fails to describe correctly plutonium-based materials since 5f electrons in such systems are strongly correlated. In order to go beyond DFT, we have treated PuO{sub 2} and {beta}-Pu{sub 2}O{sub 3} in a DFT+U framework. We show that the couple of parameters (U,J) that works well for pure Pu is also well designed for describing ground state (GS) properties of these two oxides. The major improvement with respect with DFT is that we are able to predict an insulating GS in agreement with experiments. The presence of a gap in the DOS (Density of States) of plutonium oxides should play a significant role in the predicted surface reactivity. However, performing DFT+U calculations on surfaces of plutonium oxide from scratch was too ambitious. That is why we decided, as a first step, to study the stability of the (100), (110) and (111) surfaces of PuO{sub 2} in a DFT-GGA framework. For each of these orientations, we considered various terminations. These ab initio results have been introduced in a thermodynamic model which allows us to predict the relative stability of the different terminations as a function of temperature and oxygen partial pressure (p{sub O{sub 2}}). We conclude that at room temperature and for p{sub O{sub 2}}{approx}10 atm., the polar O{sub 2}-(100) termination is favoured. The stabilization of such a polar stoichiometric surface is surprising and should be confirmed by DFT+U calculations before any final conclusion. (authors)

  8. Optimal immunization cocktails can promote induction of broadly neutralizing Abs against highly mutable pathogens

    Science.gov (United States)

    Shaffer, J. Scott; Moore, Penny L.; Kardar, Mehran; Chakraborty, Arup K.

    2016-01-01

    Strategies to elicit Abs that can neutralize diverse strains of a highly mutable pathogen are likely to result in a potent vaccine. Broadly neutralizing Abs (bnAbs) against HIV have been isolated from patients, proving that the human immune system can evolve them. Using computer simulations and theory, we study immunization with diverse mixtures of variant antigens (Ags). Our results show that particular choices for the number of variant Ags and the mutational distances separating them maximize the probability of inducing bnAbs. The variant Ags represent potentially conflicting selection forces that can frustrate the Darwinian evolutionary process of affinity maturation. An intermediate level of frustration maximizes the chance of evolving bnAbs. A simple model makes vivid the origin of this principle of optimal frustration. Our results, combined with past studies, suggest that an appropriately chosen permutation of immunization with an optimally designed mixture (using the principles that we describe) and sequential immunization with variant Ags that are separated by relatively large mutational distances may best promote the evolution of bnAbs. PMID:27791170

  9. Significant loss of hepatitis A Ab after allogeneic hematopoietic SCT in pediatric patients.

    Science.gov (United States)

    Unal Ince, E; Ertem, M; Ileri, T; Sayili, A; Belgemen, T; Uysal, Z

    2010-01-01

    Loss of specific immunity after hematopoietic SCT (HSCT) is well documented for polio, measles, mumps and tetanus. There are limited studies reporting the loss of Hepatitis A virus immunity and no reports evaluating the effect of donor immunity on Hepatitis A virus (HAV) immunity loss after HSCT. A total of 49 of the 81 patients who received HSCT at the Ankara University Pediatric HSCT Unit from January 1997 to December 2006 had HAV serology tested before HSCT and were evaluated for seroprevalence, and 30 of 49 patients were evaluated for the loss of Ab and for the effect of donor immunity on the loss of HAV Abs. The seroprevalence before HSCT was 75.5%. Loss of Ab was detected in 43.5% (10/23) of the patients. The median time to loss of Ab was 12 months (12-32 months), and 60% of these patients were seronegative at 12 months after HSCT. After HSCT, 46.7% of the patients were seronegative. Loss of Ab was higher in the seronegative donor group (75 vs 26%). The loss of HAV Ab is high after allogeneic HSCT for pediatric patients. Reimmunization should be considered for the continuation of individual and community immunity. Further studies with larger study groups are warranted to clarify the role of donor immunity on the loss of HAV immunity.

  10. Hepatoma-Targeted Radionuclide Immune Albumin Nanospheres: 131I-antiAFPMcAb-GCV-BSA-NPs

    Science.gov (United States)

    Lin, Mei; Huang, Junxing; Zhang, Dongsheng; Jiang, Xingmao; Zhang, Jia; Yu, Hong; Xiao, Yanhong; Shi, Yujuan; Guo, Ting

    2016-01-01

    An effective strategy has been developed for synthesis of radionuclide immune albumin nanospheres (131I-antiAFPMcAb-GCV-BSA-NPs). In vitro as well as in vivo targeting of 131I-antiAFPMcAb-GCV-BSA-NPs to AFP-positive hepatoma was examined. In cultured HepG2 cells, the uptake and retention rates of 131I-antiAFPMcAb-GCV-BSA-NPs were remarkably higher than those of 131I alone. As well, the uptake rate and retention ratios of 131I-antiAFPMcAb-GCV-BSA-NPs in AFP-positive HepG2 cells were also significantly higher than those in AFP-negative HEK293 cells. Compared to 131I alone, 131I-antiAFPMcAb-GCV-BSA-NPs were much more easily taken in and retained by hepatoma tissue, with a much higher T/NT. Due to good drug-loading, high encapsulation ratio, and highly selective affinity for AFP-positive tumors, the 131I-antiAFPMcAb-GCV-BSA-NPs are promising for further effective radiation-gene therapy of hepatoma. PMID:26981334

  11. Hepatoma-Targeted Radionuclide Immune Albumin Nanospheres: (131)I-antiAFPMcAb-GCV-BSA-NPs.

    Science.gov (United States)

    Lin, Mei; Huang, Junxing; Zhang, Dongsheng; Jiang, Xingmao; Zhang, Jia; Yu, Hong; Xiao, Yanhong; Shi, Yujuan; Guo, Ting

    2016-01-01

    An effective strategy has been developed for synthesis of radionuclide immune albumin nanospheres ((131)I-antiAFPMcAb-GCV-BSA-NPs). In vitro as well as in vivo targeting of (131)I-antiAFPMcAb-GCV-BSA-NPs to AFP-positive hepatoma was examined. In cultured HepG2 cells, the uptake and retention rates of (131)I-antiAFPMcAb-GCV-BSA-NPs were remarkably higher than those of (131)I alone. As well, the uptake rate and retention ratios of (131)I-antiAFPMcAb-GCV-BSA-NPs in AFP-positive HepG2 cells were also significantly higher than those in AFP-negative HEK293 cells. Compared to (131)I alone, (131)I-antiAFPMcAb-GCV-BSA-NPs were much more easily taken in and retained by hepatoma tissue, with a much higher T/NT. Due to good drug-loading, high encapsulation ratio, and highly selective affinity for AFP-positive tumors, the (131)I-antiAFPMcAb-GCV-BSA-NPs are promising for further effective radiation-gene therapy of hepatoma.

  12. PptAB Exports Rgg Quorum-Sensing Peptides in Streptococcus.

    Directory of Open Access Journals (Sweden)

    Jennifer C Chang

    Full Text Available A transposon mutagenesis screen designed to identify mutants that were defective in peptide-pheromone signaling of the Rgg2/Rgg3 pathway in Streptococcus pyogenes generated insertions in sixteen loci displaying diminished reporter activity. Fourteen unique transposon insertions were mapped to pptAB, an ABC-type transporter recently described to export sex pheromones of Enterococcus faecalis. Consistent with an idea that PptAB exports signaling peptides, the pheromones known as SHPs (short hydrophobic peptides were no longer detected in cell-free culture supernatants in a generated deletion mutant of pptAB. PptAB exporters are conserved among the Firmicutes, but their function and substrates remain unclear. Therefore, we tested a pptAB mutant generated in Streptococcus mutans and found that while secretion of heterologously expressed SHP peptides required PptAB, secretion of the S. mutans endogenous pheromone XIP (sigX inducing peptide was only partially disrupted, indicating that a secondary secretion pathway for XIP exists.

  13. Studies of the distribution of intrathecally injected 125I-tetanus antitoxin-F(ab')2

    International Nuclear Information System (INIS)

    Hanauske, A.R.

    1981-01-01

    Overall F(ab') 2 and antitetanus-f(ab') 2 - fragments were labelled with 125 I and injected i.th. into normal juvenile cats and adult rats. One group of rats was normal; in the other, unilateral local tetanus had been induced by injection of tetanus toxin into a M. gastrocnemius. The animals were sacrificed 24 h after the i.th. injection, and tissue samples were taken for histoautoradiography. 125 I-antitetanus-F(ab') 2 permeated into the extracellular space of the spinal cord, roots, and ganglia but not into the neuronal intracellular space. 125 I-overall-F(ab') showed identical permeation behaviour. 125 I-antitetanus-F(ab') 2 reacted with tetanus toxin issuing from the motoneurons after i.th. injection, forming an immunocomplex around the motorneurons. The immunocomplex was not formed around pseudo-unipolar ganglian cells in the spinal ganglia even though some of the ganglian cells contained tetanus toxin, and 125 I-antitetanus-F(ab') 2 was present in the extracellular space. As an explanation, it was suggested that tetanus toxin does not permeate into the extracellular space through the membrane of the pseudo-unipolar ganglian cells so that immune reactions will not occur. These findings help to explain the widely divergent results of tetanus therapy by means of i.th. injection of tetanus antitoxin. Recommendations for future therapy measures are derived from the findings. (orig./MG) [de

  14. Evaluation of tumor targeting with radiolabeled F(ab2 fragment of a humanized monoclonal antibody

    Directory of Open Access Journals (Sweden)

    "Babaei MH

    2002-08-01

    Full Text Available Humanized monoclonal antibody U36 and its F(ab'2 fragment, radio labeled with 125I, were tested for tumor localization in nude mice bearing a squamous cell carcinoma xenograft line derived from a head and neck carcinoma. Monoclonal antibody IgG or F(ab'2 fragment were injected in parallel and at days 1, 2 and 3, mice were dissected for determination of isotope biodistribution. IgG as well as F(ab'2 showed highly specific localization in tumor tissue. The mean tumor uptake (n=3 is expressed as the percentage of the injected dose per gram of tumor tissue (%ID/g. %ID/g of IgG was 11.7% at day 1 and decreased to 10.9% at day 3 whereas %ID/g of F(ab'2 was 2.9% at day 1 and decreased on following days. Tumor to blood ratios (T/B at day 1 were 0.86 for IgG and 1.32 for F(ab'2 and reached a maximum at day 3 with values of 4.41 and 1.84 respectively. These findings suggest that the superior tumor to non-tumor ratios in the day of 1 render the F(ab'2 fragment more qualified for specific targeting radioisotopes to tumor xenografts in this exprimental setting.

  15. ABS-SOCI: An Agent-Based Simulator of Student Sociograms

    Directory of Open Access Journals (Sweden)

    Iván García-Magariño

    2017-11-01

    Full Text Available Sociograms can represent the social relations between students. Some kinds of sociograms are more suitable than others for achieving a high academic performance of students. However, for now, at the beginning of an educative period, it is not possible to know for sure how the sociogram of a group of students will be or evolve during a semester or an academic year. In this context, the current approach presents an Agent-Based Simulator (ABS that predicts the sociogram of a group of students taking into consideration their psychological profiles, by evolving an initial sociogram through time. This simulator is referred to as ABS-SOCI (ABS for SOCIograms. For instance, this can be useful for organizing class groups for some subjects of engineering grades, anticipating additional learning assistance or testing some teaching strategies. As experimentation, ABS-SOCI has been executed 100 times for each one of four real scenarios. The results show that ABS-SOCI produces sociograms similar to the real ones considering certain sociometrics. This similarity has been corroborated by statistical binomial tests that check whether there are significant differences between the simulations and the real cases. This experimentation also includes cross-validation and an analysis of sensitivity. ABS-SOCI is free and open-source to (1 ensure the reproducibility of the experiments; (2 to allow practitioners to run simulations; and (3 to allow developers to adapt the simulator for different environments.

  16. Clinical significance of detection of GAD-Ab, ICA and IAA in patients with diabetes mellitus

    International Nuclear Information System (INIS)

    Zhou Jinhong; Liu Zhenzong; Wang Huimin

    2006-01-01

    To explore value of combined detection of glutamic acid decarboxylase antibody(GAD-Ab), islet cell antibody (ICA) and insulin autoantibody (IAA) in patients with diabetes mellitus (DM). Serum GAD-Ab, ICA and IAA were detected by chemiluminescent immunoassay and RIA in 46 of type 1 diabetes mellitus (1 DM), 78 of 2 DM respectively, and in 50 nondiabetic subjects as control group, and analysed according to the positive rates of different groups. Results showed that the positive rate of GAD-Ab was 67.39%, ICA 39.73%, IAA 23.91% in 1 DM,and that of GAD-Ab was 8.97%, ICA 15.39%, IAA 10.26% in 2 DM respectively. The positive rate of combined detection of GAD-Ab, ICA and IAA was 91.30% in patients with 1 DM, and 29.49% which was higher than that in control group (P<0.01). The detection of serum GAD-Ab,ICA and IAA might be regarded as clinical significance for classification, treatment and predict prognosis of DM. (authors)

  17. Cry1Ab protein from Bt transgenic rice does not residue in rhizosphere soil

    International Nuclear Information System (INIS)

    Wang Haiyan; Ye Qingfu; Wang Wei; Wu Licheng; Wu Weixiang

    2006-01-01

    Expression of Cry1Ab protein in Bt transgenic rice (KMD) and its residue in the rhizosphere soil during the whole growth in field, as well as degradation of the protein from KMD straw in five soils under laboratory incubation were studied. The residue of Cry1Ab protein in KMD rhizosphere soil was undetectable (below the limit of 0.5 ng/g air-dried soil). The Cry1Ab protein contents in the shoot and root of KMD were 3.23-8.22 and 0.68-0.89 μg/g (fresh weight), respectively. The half-lives of the Cry1Ab protein in the soils amended with KMD straw (4%, w/w) ranged from 11.5 to 34.3 d. The residence time of the protein varied significantly in a Fluvio-marine yellow loamy soil amended with KMD straw at the rate of 3, 4 and 7%, with half-lives of 9.9, 13.8 and 18 d, respectively. In addition, an extraction method for Cry1Ab protein in soil was developed, with extraction efficiencies of 46.4-82.3%. - Cry1Ab protein was not detected in the rhizosphere soil of field-grown Bt transgenic rice

  18. PptAB Exports Rgg Quorum-Sensing Peptides in Streptococcus.

    Science.gov (United States)

    Chang, Jennifer C; Federle, Michael J

    2016-01-01

    A transposon mutagenesis screen designed to identify mutants that were defective in peptide-pheromone signaling of the Rgg2/Rgg3 pathway in Streptococcus pyogenes generated insertions in sixteen loci displaying diminished reporter activity. Fourteen unique transposon insertions were mapped to pptAB, an ABC-type transporter recently described to export sex pheromones of Enterococcus faecalis. Consistent with an idea that PptAB exports signaling peptides, the pheromones known as SHPs (short hydrophobic peptides) were no longer detected in cell-free culture supernatants in a generated deletion mutant of pptAB. PptAB exporters are conserved among the Firmicutes, but their function and substrates remain unclear. Therefore, we tested a pptAB mutant generated in Streptococcus mutans and found that while secretion of heterologously expressed SHP peptides required PptAB, secretion of the S. mutans endogenous pheromone XIP (sigX inducing peptide) was only partially disrupted, indicating that a secondary secretion pathway for XIP exists.

  19. Complexation of AB+, AB+C, ACB+, and A(B+-stat-C) block copolymer micelles with poly(styrene sulfonate) as models for tunable gene delivery vectors

    Science.gov (United States)

    Laaser, Jennifer; Jiang, Yaming; Lohmann, Elise; Reineke, Theresa; Lodge, Timothy

    We investigate the complexation of poly(styrene sulfonate) with micelles with mixed cationic/hydrophilic coronas as models for tunable gene delivery vectors. The micelles are self-assembled from AB+, AB+C, ACB+, and A(B+-stat-C) block polymer architectures, where the hydrophobic A blocks (poly(styrene)) form the micelle cores, and the cationic B blocks (poly(dimethylamino ethyl methacrylate)) and hydrophilic, nonionic C blocks (poly(poly(ethylene glycol) methyl ether methacrylate)) form the coronas. We find that hydrophilic units do not change the colloidal stability of the complexes, and complexes based on all four micelle architectures form broad, multimodal size distributions. While complexes based on the AB+, AB+C, and ACB+polymer architectures are kinetically trapped at low ionic strength, however, those based on the A(B+-stat-C) architecture rapidly rearrange into single-micelle complexes when the linear polyanion is in excess. This suggests that the randomly-placed hydrophilic units break up the ion pairing between the cationic and anionic chains and promote formation of over-charged complexes. Design of the micelle architecture may thus provide a powerful way control the structure and stability of micelle-polyelectrolyte complexes for gene delivery applications.

  20. A survey of HK, HPt, and RR domains and their organization in two-component systems and phosphorelay proteins of organisms with fully sequenced genomes

    Directory of Open Access Journals (Sweden)

    Baldiri Salvado

    2015-08-01

    Full Text Available Two Component Systems and Phosphorelays (TCS/PR are environmental signal transduction cascades in prokaryotes and, less frequently, in eukaryotes. The internal domain organization of proteins and the topology of TCS/PR cascades play an important role in shaping the responses of the circuits. It is thus important to maintain updated censuses of TCS/PR proteins in order to identify the various topologies used by nature and enable a systematic study of the dynamics associated with those topologies. To create such a census, we analyzed the proteomes of 7,609 organisms from all domains of life with fully sequenced and annotated genomes. To begin, we survey each proteome searching for proteins containing domains that are associated with internal signal transmission within TCS/PR: Histidine Kinase (HK, Response Regulator (RR and Histidine Phosphotranfer (HPt domains, and analyze how these domains are arranged in the individual proteins. Then, we find all types of operon organization and calculate how much more likely are proteins that contain TCS/PR domains to be coded by neighboring genes than one would expect from the genome background of each organism. Finally, we analyze if the fusion of domains into single TCS/PR proteins is more frequently observed than one might expect from the background of each proteome. We find 50 alternative ways in which the HK, HPt, and RR domains are observed to organize into single proteins. In prokaryotes, TCS/PR coding genes tend to be clustered in operons. 90% of all proteins identified in this study contain just one of the three domains, while 8% of the remaining proteins combine one copy of an HK, a RR, and/or an HPt domain. In eukaryotes, 25% of all TCS/PR proteins have more than one domain. These results might have implications for how signals are internally transmitted within TCS/PR cascades. These implications could explain the selection of the various designs in alternative circumstances.