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Sample records for 8-m gemini south

  1. AO operations at Gemini South

    NASA Astrophysics Data System (ADS)

    Marin, Eduardo; Cardwell, Andrew; Pessev, Peter

    2014-08-01

    The 8m Gemini South telescope is entering an exciting new era of AO operations, which put it at the forefront of astronomical AO in terms of both wide field AO, and extreme-AO systems. Major milestones achieved were the successful commissioning of GeMS, in 2012, and GPI, in late 2013 and early 2014. Currently we are operating two of the worlds most advanced astronomical AO systems. Gemini, running primarily in queue, must balance the promise of AO with the demands of the community to use non-AO instruments. We discuss the current state of the two AO systems, and their operational models. The preparations that go into planning each AO run, the difficulties in scheduling around non-AO instruments, and the differences between scheduling LGS AO and non-LGS AO are discussed.

  2. Acquisition and guiding unit for Gemini 8-m telescopes: a progress report

    NASA Astrophysics Data System (ADS)

    Heilemann, Wolfgang; Naumann, Helgard

    1998-07-01

    An international partnership of the USA, UK, Canada, Chile, Argentina and Brazil are projecting two high performance 8- meter Aperture Optical/Infrared Telescopes to be commissioned between the years 1998 and 2000 at Mauna Kea, Hawaii, and Cerro Pachon, Chile. The aim is to exploit the best natural observing conditions to undertake a broad range of astronomical research programs within the national communities of other countries. Zeiss was awarded two mayor contracts within this project, to design, manufacture and test the secondary mirrors and the Gemini Acquisition and Guiding system (GAG) for the 8m telescopes. The current paper refers to the GAG. The Gemini Acquisition and Guiding Unit are complex integrated systems, including optics, mechanical assemblies, detectors and control and signal processing software. The project is to be accomplished under subcontract and in cooperation with the Royal Greenwich Observatory in the United Kingdom. We briefly review the technological and astronomical background of the project and the technical specification of the GAG. The paper describes the design of the Acquisition and Guidance Unit, highlights some design criteria and discusses the expected performance. A report about the actual status of work is given.

  3. Gemini planet imager integration to the Gemini South telescope software environment

    NASA Astrophysics Data System (ADS)

    Rantakyrö, Fredrik T.; Cardwell, Andrew; Chilcote, Jeffrey; Dunn, Jennifer; Goodsell, Stephen; Hibon, Pascale; Macintosh, Bruce; Quiroz, Carlos; Perrin, Marshall D.; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Winge, Claudia; Galvez, Ramon; Gausachs, Gaston; Hardie, Kayla; Hartung, Markus; Luhrs, Javier; Poyneer, Lisa; Thomas, Sandrine

    2014-08-01

    The Gemini Planet Imager is an extreme AO instrument with an integral field spectrograph (IFS) operating in Y, J, H, and K bands. Both the Gemini telescope and the GPI instrument are very complex systems. Our goal is that the combined telescope and instrument system may be run by one observer operating the instrument, and one operator controlling the telescope and the acquisition of light to the instrument. This requires a smooth integration between the two systems and easily operated control interfaces. We discuss the definition of the software and hardware interfaces, their implementation and testing, and the integration of the instrument with the telescope environment.

  4. Properties of Ellipticity Correlation with Atmospheric Structure from Gemini South

    SciTech Connect

    Asztalos, S J; Treadway, T; de Vries, W H; Rosenberg, L J; Burke, D; Claver, C; Saha, A; Puxley, P

    2006-12-21

    Cosmic shear holds great promise for a precision independent measurement of {Omega}{sub m}, the mass density of the universe relative to the critical density. The signal is expected to be weak, so a thorough understanding of systematic effects is crucial. An important systematic effect is the atmosphere: shear power introduced by the atmosphere is larger than the expected signal. Algorithms exist to extract the cosmic shear from the atmospheric component, though a measure of their success applied to a range of seeing conditions is lacking. To gain insight into atmospheric shear, Gemini South imaging in conjunction with ground condition and satellite wind data were obtained. We find that under good seeing conditions Point-Spread-Function (PSF) correlations persist well beyond the separation typical of high-latitude stars. Under these conditions, ellipticity residuals based on a simple PSF interpolation can be reduced to within a factor of a few of the shot-noise induced ellipticity floor. We also find that the ellipticity residuals are highly correlated with wind direction. Finally, we correct stellar shapes using a more sophisticated procedure and generate shear statistics from stars. Under all seeing conditions in our data set the residual correlations lie everywhere below the target signal level. For good seeing we find that the systematic error attributable to atmospheric turbulence is comparable in magnitude to the statistical error (shape noise) over angular scales relevant to present lensing surveys.

  5. Properties of Ellipticity Correlation with Atmospheric Structure From Gemini South

    SciTech Connect

    Asztalos, Stephen J.; de Vries, W.H.; Rosenberg, L.J; Treadway, T.; Burke, D.; Claver, C.; Saha, A.; Puxley, P.; /Gemini Observ., La Serena

    2007-01-17

    Cosmic shear holds great promise for a precision independent measurement of {Omega}{sub m}, the mass density of the universe relative to the critical density. The signal is expected to be weak, so a thorough understanding of systematic effects is crucial. An important systematic effect is the atmosphere: shear power introduced by the atmosphere is larger than the expected signal. Algorithms exist to extract the cosmic shear from the atmospheric component, though a measure of their success applied to a range of seeing conditions is lacking. To gain insight into atmospheric shear, Gemini South imaging in conjunction with ground condition and satellite wind data were obtained. We find that under good seeing conditions Point-Spread-Function (PSF) correlations persist well beyond the separation typical of high-latitude stars. Under these conditions, ellipticity residuals based on a simple PSF interpolation can be reduced to within a factor of a few of the shot-noise induced ellipticity floor. We also find that the ellipticity residuals are highly correlated with wind direction. Finally, we correct stellar shapes using a more sophisticated procedure and generate shear statistics from stars. Under all seeing conditions in our data set the residual correlations lie everywhere below the target signal level. For good seeing we find that the systematic error attributable to atmospheric turbulence is comparable in magnitude to the statistical error (shape noise) over angular scales relevant to present lensing surveys.

  6. Gemini primary mirror support system

    NASA Astrophysics Data System (ADS)

    Stepp, Larry M.; Huang, Eugene W.; Cho, Myung K.

    1994-06-01

    The primary mirror selected for the Gemini 8-m Telescopes is a thin meniscus made of Corning ULE(superscript TM) glass. The conceptual design of the Gemini support system has evolved in response to the properties of the meniscus mirror and the functional requirements of the Gemini Telescopes. This paper describes the design requirements, the design features, and predicted performance of this system.

  7. Gemini-South+FLAMINGOS Demonstration Science: Near-Infrared Spectroscopy of the z = 5.77 Quasar SDSS J083643.85+005453.3

    NASA Astrophysics Data System (ADS)

    Stern, Daniel; Hall, Patrick B.; Barrientos, L. Felipe; Bunker, Andrew J.; Elston, Richard; Ledlow, M. J.; Raines, S. Nicholas; Willis, Jon

    2003-10-01

    We report an infrared 1-1.8 μm (J+H-band), low-resolution (R=450) spectrogram of the highest redshift radio-loud quasar currently known, SDSS J083643.85+005453.3, obtained during the spectroscopic commissioning run of the FLAMINGOS multiobject, near-IR spectrograph at the 8 m Gemini-South Observatory. These data show broad emission from both C IV λ1549 and C III] λ1909, with strengths comparable to lower redshift quasar composite spectra. The implication is that there is substantial enrichment of the quasar environment, even at times less than a billion years after the big bang. The redshift derived from these features is z=5.774+/-0.003, more accurate and slightly lower than the z=5.82 reported in the discovery paper based on the partially absorbed Lyα emission line. The infrared continuum is significantly redder than lower redshift quasar composites. Fitting the spectrum from 1.0 to 1.7 μm with a power law fν~ν-α, the derived power-law index is α=1.55 compared to the average continuum spectral index <α>=0.44 derived from the first Sloan Digital Sky Survey composite quasar. Assuming an SMC-like extinction curve, we infer a color excess of E(B-V)=0.09+/-0.01. Only ~6% of quasars in the optically selected Sloan Digital Sky Survey show comparable levels of dust reddening. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina).

  8. The Gemini Planet Imager

    SciTech Connect

    Macintosh, B; al., e

    2006-05-02

    The next major frontier in the study of extrasolar planets is direct imaging detection of the planets themselves. With high-order adaptive optics, careful system design, and advanced coronagraphy, it is possible for an AO system on a 8-m class telescope to achieve contrast levels of 10{sup -7} to 10{sup -8}, sufficient to detect warm self-luminous Jovian planets in the solar neighborhood. Such direct detection is sensitive to planets inaccessible to current radial-velocity surveys and allows spectral characterization of the planets, shedding light on planet formation and the structure of other solar systems. We have begun the construction of such a system for the Gemini Observatory. Dubbed the Gemini Planet Imager (GPI), this instrument should be deployed in 2010 on the Gemini South telescope. It combines a 2000-actuator MEMS-based AO system, an apodized-pupil Lyot coronagraph, a precision infrared interferometer for real-time wavefront calibration at the nanometer level, and a infrared integral field spectrograph for detection and characterization of the target planets. GPI will be able to achieve Strehl ratios > 0.9 at 1.65 microns and to observe a broad sample of science targets with I band magnitudes less than 8. In addition to planet detection, GPI will also be capable of polarimetric imaging of circumstellar dust disks, studies of evolved stars, and high-Strehl imaging spectroscopy of bright targets. We present here an overview of the GPI instrument design, an error budget highlighting key technological challenges, and models of the system performance.

  9. Characterization and monitoring of Flamingos-II, a near-IR imager and spectrograph at Gemini South

    NASA Astrophysics Data System (ADS)

    Krogsrud, David; Diaz, Ruben; Ferrero, Gabriel; Mora, Marcelo; Navarete, Felipe; Schirmer, Mischa

    2015-01-01

    We present results of the characterization and continual monitoring of the Flamingos-II instrument. Currently installed at Gemini South Observatory, Flamingos-II is a near-IR imager and longslit/multi-object spectrograph. In addition to the characterization of the detector, methodologies and results of the Science Verification pipeline, Telluric corrections, and Multi-Object Spectrograph (MOS) mask design software are presented.

  10. Instrumentation at Gemini Observatory

    NASA Astrophysics Data System (ADS)

    Kleinman, S. J.; Boccas, Maxime; Goodsell, Stephen J.; Gomez, Percy; Murowinski, Rick; Chené, André-Nicolas; Henderson, David

    2014-07-01

    Gemini South's instrument suite has been completely transformed since our last biennial update. We commissioned the Gemini Multi-Conjugate Adaptive Optics System (GeMS) and its associated Gemini South Adaptive Optics Imager (GSAOI) as well as Flamingos-2, our long-slit and multi-object infrared imager and spectrograph, and the Gemini Planet Imager (GPI). We upgraded the CCDs in GMOS-S, our multi-object optical imager and spectrograph, with the GMOS-N CCD upgrade scheduled for 2015. Our next instrument, the Gemini High-resolution Optical SpecTrograph (GHOST) is in its preliminary design stage and we are making plans for the instrument to follow:Gen4#3.

  11. The Gemini Planet Imager: From Science to Design to Construction

    SciTech Connect

    Macintosh, B; Graham, J R; Palmer, D; Doyon, R; Dunn, J; Gavel, D; Larkin, J; Oppenheimer, B; Saddlemyer, L; Sivaramakrishnan, A; Wallace, J K; Bauman, B; Erickson, D; Marois, C; Poyneer, L; Soummer, R

    2008-07-01

    The Gemini Planet Imager (GPI) is a facility instrument under construction for the 8-m Gemini South telescope. It combines a 1500 subaperture AO system using a MEMS deformable mirror, an apodized-pupil Lyot coronagraph, a high-accuracy IR interferometer calibration system, and a near-infrared integral field spectrograph to allow detection and characterization of self-luminous extrasolar planets at planet/star contrast ratios of 10{sup -7}. I will discuss the evolution from science requirements through modeling to the final detailed design, provide an overview of the subsystems and show models of the instrument's predicted performance.

  12. Integration and test of the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Thomas, Sandrine J.; Poyneer, Lisa; De Rosa, Rob; Macintosh, Bruce; Dillon, Daren; Wallace, James K.; Palmer, David; Gavel, Donald; Bauman, Brian; Saddlemyer, Leslie; Goodsell, Stephen

    2011-10-01

    Exoplanet imaging is driving a race to higher contrast imaging, both from earth and from space. Next-generation instruments such as the Gemini Planet Imager (GPI) and SPHERE are designed to achieve contrast ratios of 10-6 - 10-7 this requires very good wavefront correction and coronagraphic control of diffraction. GPI is a facility instrument, now in integration and test, with first light on the 8-m Gemini South telescope expected by the middle of 2012. It combines a 1700 subaperture AO system using a MEMS deformable mirror, an apodized-pupil Lyot coronagraph, a high-accuracy IR interferometric wavefront calibration system, and a nearinfrared integral field spectrograph to allow detection and characterization of self-luminous extrasolar planets at planet/star contrast ratios of 10-7. In this paper we will discuss the status of the integration and test now taking place at the University of Santa Cruz California.

  13. Gemini Space Program emblem

    NASA Technical Reports Server (NTRS)

    1965-01-01

    The insignia of the Gemini space program is a disc of dark blue as a background for a gold Zodiac Gemini symbol. A white star on each of the two vertical curves of the Gemini symbol represent the Gemini twins, Pollux and Castor.

  14. Gemini planet imager observational calibrations VII: on-sky polarimetric performance of the Gemini planet imager

    NASA Astrophysics Data System (ADS)

    Wiktorowicz, Sloane J.; Millar-Blanchaer, Max; Perrin, Marshall D.; Graham, James R.; Fitzgerald, Michael P.; Maire, Jérôme; Ingraham, Patrick; Savransky, Dmitry; Macintosh, Bruce A.; Thomas, Sandrine J.; Chilcote, Jeffrey K.; Draper, Zachary H.; Song, Inseok; Cardwell, Andrew; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Rantakyrö, Fredrik; Sadakuni, Naru

    2014-07-01

    We present on-sky polarimetric observations with the Gemini Planet Imager (GPI) obtained at straight Cassegrain focus on the Gemini South 8-m telescope. Observations of polarimetric calibrator stars, ranging from nearly un- polarized to strongly polarized, enable determination of the combined telescope and instrumental polarization. We find the conversion of Stokes I to linear and circular instrumental polarization in the instrument frame to be I --> (QIP, UIP, PIP, VIP) = (-0.037 +/- 0.010%, +0.4338 +/- 0.0075%, 0.4354 +/- 0.0075%, -6.64 +/- 0.56%). Such precise measurement of instrumental polarization enables ~0.1% absolute accuracy in measurements of linear polarization, which together with GPI's high contrast will allow GPI to explore scattered light from circumstellar disk in unprecedented detail, conduct observations of a range of other astronomical bodies, and potentially even study polarized thermal emission from young exoplanets. Observations of unpolarized standard stars also let us quantify how well GPI's differential polarimetry mode can suppress the stellar PSF halo. We show that GPI polarimetry achieves cancellation of unpolarized starlight by factors of 100-200, reaching the photon noise limit for sensitivity to circumstellar scattered light for all but the smallest separations at which the calibration for instrumental polarization currently sets the limit.

  15. A two deformable-mirror concept to improve the laser efficiency of Gemini South MCAO (GeMS)

    NASA Astrophysics Data System (ADS)

    Béchet, Clémentine; Guesalaga, Andrés; Neichel, Benoit; Fesquet, Vincent; Guzman, Dani

    2013-12-01

    Gem's is the first laser-based multi-conjugate adaptive optics offeredto the astronomical community. Its asterism of 5 laser guide stars hasrecently proved to provide very uniform turbulence correction over the85''x85'' observation field, opening the new era of wide-field highangular resolution studies from the ground. Good AO performance requireshowever good wavefront sensing measurements from the laser guide stars,which directly depends on the quality of the laser spot image. Theoptimization of the lasers launched out of the telescope requires tofollow frequent and constraining calibrations and alignments procedures(quasi-static aberrations), in order to guarantee satisfying amplitudeand phase of the beam. These complex and time-consuming procedures willstrongly penalize the availability of Gem's.A laser beam shaping concept has been recently suggested to overcomesuch issues. It consists in applying, in the beam transfer optics, afield-conjugation thanks to 2 deformable mirrors. We review thisconcept. In particular, we discuss the criterion to be optimized and thedesired amplitude and phase shapes at the output of the Gemini beamtransfer optics. We deduce the control to be applied to the mirrors fromthe optimization of the signal-to-noise ratio of the wavefront sensingin Gem's. An iterative algorithm is used to estimate the phases, with aweighted least-squares unwrapper to avoid branch points. This algorithmefficiency is demonstrated with adequate beam shaping simulations.Discussion is made about how to implement such concept at Gemini.

  16. Gemini South Multi-Object Spectrograph (GMOS-S) detector Video boards upgrade: improved performance for the Hamamatsu CCDs.

    NASA Astrophysics Data System (ADS)

    Gimeno, German; Boucher, Luc; Chiboucas, Kristin; Hibon, Pascale; Lazo, Manuel; Murowinski, Richard; Rippa, Matthew; Rogers, Rolando; Rojas, Roberto; Roth, Katherine; White, John

    2016-01-01

    GMOS-S was upgraded with new Hamamatsu CCDs on June 2014, featuring an improved red sensitivity with respect to the previous detectors and significantly less fringing. Early after the commissioning, an issue was identified when observing in any of the binned readout modes, namely that saturated pixels produced a decrease of counts with respect to the bias level in neighboring pixels. This effect, also known as 'banding', spanned the entire width of the amplifier, and while it did not destroy information, it rendered data reduction very cumbersome. Making matters worse, due to the saturation of a bad column on amplifier number 5 (on CCD2, near the middle of the focal plane), it ended up affecting the entire amplifier for almost all exposures longer than a minute. A team of Gemini instrument scientists and engineers investigated the issue and identified the root cause of the problem as originated in the ARC controller video boards. After significant lab testing, it was verified that a newly available revision of the video boards would solve the problem, though modification of the software was required in order to be compatible with them. This work was performed during the last semester of 2014 and the first semester of 2015. The new video boards were installed and commissioned during August 2015. As of September 1st, the new boards are fully installed and integrated, and the 'banding' effect has been completely eliminated. A short period of time was devoted to the recharacterization of the detector system and the new values for the gains, read noise and full well capacity have been derived. As an added benefit, the full well was increased by ~ 10 percent with respect to the previous value. The GMOS-S new detectors are now operating normally in the Gemini observing queue, and performing at full capacity.

  17. Gemini Planet Imager: From Integration And Test To Planning Observations

    NASA Astrophysics Data System (ADS)

    Thomas, Sandrine; Macintosh, B.; Palmer, D.; Saddlemyer, L.; Wallace, J. K.; Gavel, D.; Larkin, J.; Graham, J.; Doyon, R.; Oppenheimer, B.; GOODSell, S.; GPI Team

    2012-01-01

    Achieving higher contrast is an ongoing theme in exoplanet imaging, both from earth and from space. Next-generation instruments such as the Gemini Planet Imager and SPHERE are designed to achieve contrast ratios of 106 - 107 from the ground; this requires very good static and dynamic wavefront correction as well as very good coronagraphic control of diffraction. GPI is a facility instrument, now in integration and test at the Laboratory for Adaptive Optics in Santa Cruz California. Its first light on the 8-m Gemini South telescope is expected by the end of 2012. GPI combines a high density MEMS deformable mirror (1700 subapertures), an apodized-pupil Lyot coronagraph and a high-accuracy IR interferometer calibration system. The instrument is a near-infrared integral field spectrograph (IFS) that will allow detection and characterization of self-luminous extrasolar planets at planet/star contrast ratios of 10-7. One additional feature of the IFS is a polarimetric mode to characterize scattered light from disks. We will discuss the status of the integration and test happening at the University of Santa Cruz California and discuss its scientific capabilities.

  18. Current and future facility instruments at the Gemini Observatory

    NASA Astrophysics Data System (ADS)

    Jensen, Joseph B.; Kleinman, Scot J.; Simons, Douglas A.; Lazo, Manuel; Rigaut, François; White, John K.

    2008-07-01

    At the present time, several new Gemini instruments are being delivered and commissioned. The Near-Infrared Coronagraph has been extensively tested and commissioned on the Gemini-South telescope, and will soon begin a large survey to discover extrasolar planets. The FLAMINGOS-2 near-IR multi-object spectrograph is nearing completion at the University of Florida, and is expected to be delivered to Gemini-South by the end of 2008. Gemini's Multi-Conjugate Adaptive Optics bench has been successfully integrated and tested in the lab, and now awaits integration with the laser system and the Gemini-South AO Imager on the telescope. We also describe our efforts to repair thermal damage to the Gemini Near-IR Spectrograph that occurred last year. Since the last update, progress has been made on several of Gemini's next generation of ambitious "Aspen" instruments. The Gemini Planet Imager is now in the final design phase, and construction is scheduled to begin shortly. Two competitive conceptual design studies for the Wide-Field Fiber Multi-Object Spectrometer have now started. The Mauna Kea ground layer monitoring campaign has collected data for well over a year in support of the planning process for a future Ground Layer Adaptive Optics system.

  19. Gemini IRAF: Data reduction software for the Gemini telescopes

    NASA Astrophysics Data System (ADS)

    Gemini Observatory; AURA

    2016-08-01

    The Gemini IRAF package processes observational data obtained with the Gemini telescopes. It is an external package layered upon IRAF and supports data from numerous instruments, including FLAMINGOS-2, GMOS-N, GMOS-S, GNIRS, GSAOI, NIFS, and NIRI. The Gemini IRAF package is organized into sub-packages; it contains a generic tools package, "gemtools", along with instrument-specific packages. The raw data from the Gemini facility instruments are stored as Multi-Extension FITS (MEF) files. Therefore, all the tasks in the Gemini IRAF package, intended for processing data from the Gemini facility instruments, are capable of handling MEF files.

  20. The Gemini NICI Planet-Finding Campaign: The Companion Detection Pipeline

    NASA Astrophysics Data System (ADS)

    Wahhaj, Zahed; Liu, Michael C.; Biller, Beth A.; Nielsen, Eric L.; Close, Laird M.; Hayward, Thomas L.; Hartung, Markus; Chun, Mark; Ftaclas, Christ; Toomey, Douglas W.

    2013-12-01

    We present high-contrast image processing techniques used by the Gemini NICI Planet-Finding Campaign to detect faint companions to bright stars. The Near-Infrared Coronographic Imager (NICI) is an adaptive optics instrument installed on the 8 m Gemini South telescope, capable of angular and spectral difference imaging and specifically designed to image exoplanets. The Campaign data pipeline achieves median contrasts of 12.6 mag at 0.''5 and 14.4 mag at 1'' separation, for a sample of 45 stars (V = 4.3-13.9 mag) from the early phase of the campaign. We also present a novel approach to calculating contrast curves for companion detection based on 95% completeness in the recovery of artificial companions injected into the raw data, while accounting for the false-positive rate. We use this technique to select the image processing algorithms that are more successful at recovering faint simulated point sources. We compare our pipeline to the performance of the Locally Optimized Combination of Images (LOCI) algorithm for NICI data and do not find significant improvement with LOCI. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  1. Legacy of Gemini

    NASA Technical Reports Server (NTRS)

    1967-01-01

    In the perspective of a single composite mission, this documentary illustrates the major accomplishments of the Gemini two man space flights and the significance of these flights to the Apollo Program. This film includes outstanding photography of the Earth and man in space.

  2. Gemini planet imager one button approach

    NASA Astrophysics Data System (ADS)

    Dunn, Jennifer; Kerley, Dan; Saddlemyer, Leslie; Smith, Malcolm; Wooff, Robert; Savransky, Dmitry; Palmer, David; Macintosh, Bruce; Weiss, Jason; Quiroz, Carlos; Rantakyrö, Fredrik T.; Goodsell, Stephen J.

    2014-07-01

    The Gemini Planet Imager (GPI) is an "extreme" adaptive optics coronagraph system that is now on the Gemini South telescope in Chile. This instrument is composed of three different systems that historically have been separate instruments. These systems are the extreme Adaptive Optics system, with deformable mirrors, including a high-order 64x64 element MEMS system; the Science Instrument, which is a near-infrared integral field spectrograph; and the Calibration system, a precision IR wavefront sensor that also holds key coronagraph components. Each system coordinates actions that require precise timing. The observatory is responsible for starting these actions and has typically done this asynchronously across independent systems. Despite this complexity we strived to provide an interface that is as close to a onebutton approach as possible. This paper will describe the sequencing of these systems both internally and externally through the observatory.

  3. The Gemini NICI planet-finding campaign: The companion detection pipeline

    SciTech Connect

    Wahhaj, Zahed; Liu, Michael C.; Nielsen, Eric L.; Chun, Mark; Ftaclas, Christ; Biller, Beth A.; Close, Laird M.; Hayward, Thomas L.; Hartung, Markus

    2013-12-10

    We present high-contrast image processing techniques used by the Gemini NICI Planet-Finding Campaign to detect faint companions to bright stars. The Near-Infrared Coronographic Imager (NICI) is an adaptive optics instrument installed on the 8 m Gemini South telescope, capable of angular and spectral difference imaging and specifically designed to image exoplanets. The Campaign data pipeline achieves median contrasts of 12.6 mag at 0.''5 and 14.4 mag at 1'' separation, for a sample of 45 stars (V = 4.3-13.9 mag) from the early phase of the campaign. We also present a novel approach to calculating contrast curves for companion detection based on 95% completeness in the recovery of artificial companions injected into the raw data, while accounting for the false-positive rate. We use this technique to select the image processing algorithms that are more successful at recovering faint simulated point sources. We compare our pipeline to the performance of the Locally Optimized Combination of Images (LOCI) algorithm for NICI data and do not find significant improvement with LOCI.

  4. Gemini facility calibration unit

    NASA Astrophysics Data System (ADS)

    Ramsay-Howat, Suzanne K.; Harris, John W.; Gostick, David C.; Laidlaw, Ken; Kidd, Norrie; Strachan, Mel; Wilson, Ken

    2000-08-01

    High-quality, efficient calibration instruments is a pre- requisite for the modern observatory. Each of the Gemini telescopes will be equipped with identical facility calibration units (GCALs) designed to provide wavelength and flat-field calibrations for the suite of instruments. The broad range of instrumentation planned for the telescopes heavily constrains the design of GCAL. Short calibration exposures are required over wavelengths from 0.3micrometers to 5micrometers , field sizes up to 7 arcminutes and spectral resolution from R-5 to 50,000. The output from GCAL must mimic the f-16 beam of the telescope and provide a uniform illumination of the focal plane. The calibration units are mounted on the Gemini Instrument Support Structure, two meters from the focal pane, necessitating the use of large optical components. We will discuss the opto-mechanical design of the Gemini calibration unit, with reference to those feature which allow these stringent requirements to be met. A novel reflector/diffuser unit replaces the integration sphere more normally found in calibration systems. The efficiency of this system is an order of magnitude greater than for an integration sphere. A system of two off-axis mirrors reproduces the telescope pupil and provides the 7 foot focal plane. The results of laboratory test of the uniformity and throughput of the GCAL will be presented.

  5. Gemini Scout Control Software

    SciTech Connect

    Clinton Hobart, Justin Garretson

    2010-11-23

    The Gemini Scout Control Software consists of two Windows applications that allow the Gemini Scout vehicle to be controlled by an operator. The Embedded application runs on the vehicle's Gemini Scout Control Software onboard computer and controls the vehicle's various motors and sensors. This application reports the vehicle's status and receives vehicle commands overthe local-area-network. The Embedded applicationalso allows the user to control the vehicle using a USB game-pad connected directly to the vehicle. The Operator Control Unit (OCU) application runs on an external PC and communicates with the vehicle via an Ethernet connection. The OCU application sends commands to and receives data from the Embedded application running on the vehicle. The OCU application also communicates directly with the digital video encoders and radios in order to display video from the vehicle's cameras and the status of the radio link. The OCU application has a graphical user interface (GUI) that displays the vehicle's status and allows the user to change various vehicle settings. Finally, the OCU application receives input from a USB game-pad connected to the PC in order to control the vehicle's functions.

  6. Gemini Scout Control Software

    2010-11-23

    The Gemini Scout Control Software consists of two Windows applications that allow the Gemini Scout vehicle to be controlled by an operator. The Embedded application runs on the vehicle's Gemini Scout Control Software onboard computer and controls the vehicle's various motors and sensors. This application reports the vehicle's status and receives vehicle commands overthe local-area-network. The Embedded applicationalso allows the user to control the vehicle using a USB game-pad connected directly to the vehicle. Themore » Operator Control Unit (OCU) application runs on an external PC and communicates with the vehicle via an Ethernet connection. The OCU application sends commands to and receives data from the Embedded application running on the vehicle. The OCU application also communicates directly with the digital video encoders and radios in order to display video from the vehicle's cameras and the status of the radio link. The OCU application has a graphical user interface (GUI) that displays the vehicle's status and allows the user to change various vehicle settings. Finally, the OCU application receives input from a USB game-pad connected to the PC in order to control the vehicle's functions.« less

  7. Project Gemini online digital archive

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2012-01-01

    An archive containing the first high-resolution digital scans of the original flight films from Project Gemini, the second U.S. human spaceflight program, was unveiled by the NASA Johnson Space Center and Arizona State University's (ASU) School of Earth and Space Exploration on 6 January. The archive includes images from 10 flights. Project Gemini, which ran from 1964 to 1966, followed Project Mercury and preceded the Apollo spacecraft. Mercury and Apollo imagery are also available through ASU. For more information, see http://tothemoon.ser.asu.edu/gallery/gemini and http://apollo.sese.asu.edu/index.html.

  8. Janus and Gemini Nanoplates

    NASA Astrophysics Data System (ADS)

    Cheng, Zhengdong; Mejia, Andres; Chang, Ya-Wen; He, Peng; Diaz, Agustin; Clearfield, Abraham

    2011-03-01

    Janus particles were used to make stable Pickering emulsions (emulsions stabilized by particles). Here we demonstrated a novel method to produce high aspect ratio Janus plates with atomic thickness. Gemini plates with only the edges functionalized are also fabricated. These novel nanoplates are observed to have super surface activity. Most importantly, these particles overcome the two opposite effects in the stabilization of Pickering emulsions using spherical particles: stabilization requires particles as small as possible; but smaller particles are easy to escape the interface due to Brownian motion since the adsorption energy to the oil-water interface is proportional to the diameter of the spheres. Our nanoplates have a large aspect ratio due to the extremely thin thickness, which offers extraordinary stability to the liquid film between two emulsions to prevent coalescence. In the meantime, their large lateral surface area offers strong adsorption energy at the oil-water interface.

  9. Gemini Planet Imager First Light and Campaign Survey

    NASA Astrophysics Data System (ADS)

    Patience, J.; Macintosh, B. A.; Graham, J. R.; Gpies Team

    2014-03-01

    Detecting, characterizing, and modeling exoplanets are among the fastestgrowing and highest-profile fields in current international astrophysics research. With direct imaging, it is possible to investigate the frequency of planetary systems with an architecture similar to that of the Solar System by detecting Jupiter-like planets in orbits comparable to the location of the giant planets in the Solar System. The detection and characterization of a new population of wide orbit exoplanets is essential to obtain a full census of planetary systems and to provide crucial tests of planet formation and evolution theories. Directly imaged planets also present important systems for which the atmospheric properties can be characterized. Achieving this potential is the fundamental goal of the Gemini Planet Imager (GPI). GPI, a facility instrument for the Gemini South Observatory, will be the most sensitive planet imager ever constructed, an order of magnitude more powerful than current facilities and capable of discovering young (<1 GYr) planets from 5-100 AU. The Gemini Observatory has allocated our team 890 hours of telescope time to carry out the Gemini Planet Imager Exoplanet Survey (GPIES) - the largest single allocation in the history of Gemini. The GPIES survey is designed to observe ~600 young, nearby stars, at high sensitivity, optimized to provide detection and basic characterization of 20-50 1-10 MJ planets.

  10. Gemini 9 spacecraft recovery operations

    NASA Technical Reports Server (NTRS)

    1966-01-01

    The Gemini 9-A spacecraft, with Astronauts Thomas Stafford and Eugene Cernan still inside, in water as the aircraft carrier U.S.S. Wasp, the recovery ship, comes alongside to recover the astronauts and their spaceship.

  11. Gemini Frontier Fields: Wide-field Adaptive Optics Ks-band Imaging of the Galaxy Clusters MACS J0416.1-2403 and Abell 2744

    NASA Astrophysics Data System (ADS)

    Schirmer, M.; Carrasco, E. R.; Pessev, P.; Garrel, V.; Winge, C.; Neichel, B.; Vidal, F.

    2015-04-01

    We have observed two of the six Frontier Fields galaxy clusters, MACS J0416.1-2403 and Abell 2744, using the Gemini Multi-Conjugate Adaptive Optics System (GeMS) and the Gemini South Adaptive Optics Imager (GSAOI). With 0.″ 08-0.″ 10 FWHM our data are nearly diffraction-limited over a 100\\prime\\prime × 100\\prime\\prime wide area. GeMS/GSAOI complements the Hubble Space Telescope (HST) redwards of 1.6 μm with twice the angular resolution. We reach a 5σ depth of {{K}s}˜ 25.6 mag (AB) for compact sources. In this paper, we describe the observations, data processing, and initial public data release. We provide fully calibrated, co-added images matching the native GSAOI pixel scale as well as the larger plate scales of the HST release, adding to the legacy value of the Frontier Fields. Our work demonstrates that even for fields at high galactic latitude where natural guide stars are rare, current multi-conjugated adaptive optics technology at 8 m telescopes has opened a new window on the distant universe. Observations of a third Frontier Field, Abell 370, are planned. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). Based on observations made with ESO Telescopes at the La Silla and Paranal Observatories, Chile.

  12. The Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Graham, James R.; Macintosh, Bruce; Perrin, Marshall D.; Ingraham, Patrick; Konopacky, Quinn M.; Marois, Christian; Poyneer, Lisa; Bauman, Brian; Barman, Travis; Burrows, Adam Seth; Cardwell, Andrew; Chilcote, Jeffrey K.; De Rosa, Robert John J.; Dillon, Daren; Doyon, Rene; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P.; Gavel, Donald; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Kalas, Paul; Larkin, James E.; Maire, Jerome; Marchis, Franck; Marley, Mark S.; McBride, James; Millar-Blanchaer, Max; Morzinski, Kathleen M.; Nielsen, Eric L.; Norton, Andew; Oppenheimer, Rebecca; Palmer, David; Patience, Jenny; Pueyo, Laurent; Rantakyro, Fredrik; Sadakuni, Naru; Saddlemeyer, Leslie; Savransky, Dmitry; Serio, Andrew W.; Soummer, Remi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wang, Jason; Wiktorowicz, Sloane; Wolff, Schulyer; Gpi/Gpies Team

    2015-01-01

    The Gemini Planet Imager (GPI) is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of GPI has been tuned for maximum sensitivity to faint planets near bright stars. GPI has undergone a year of commissioning, verification, and calibration work. We have achieved an estimated H-band contrast (5-sigma) of 106 at 0.75 arcseconds and 105 at 0.35 arcseconds in spectral mode, and suppression of unpolarized starlight by a factor of 800 in imaging polarimetry mode. Early science observations include study of the spectra of β Pic b and HR 8799, orbital investigations of β Pic b and PZ Tel, and observations of the debris disk systems associated with β Pic, AU Mic, and HR 4796A. An 890-hour exoplanet survey with GPI is scheduled to begin in late 2014. A status report for the campaign will be presented.

  13. Recovery of Gemini 4 spacecraft and astronauts

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Recovery of Gemini 4 spacecraft and astronauts. Views include Astronaut James A. McDivitt, command pilot of the Gemini 4 space flight, sitting in life raft awaiting pickup by helicopter from the recovery ship, the aircraft carrier U.S.S. Wasp (33490); Navy frogmen stand on the flotation collar of the Gemini 4 spacecraft during recovery operations (33491).

  14. Index maps for Gemini earth photography

    NASA Technical Reports Server (NTRS)

    Giddings, L. E.

    1975-01-01

    Index maps for the Gemini missions are presented; these are for the Gemini 3 through Gemini 12 missions. The maps are divided into four sections: the whole earth; the Western Hemisphere and eastern Pacific Ocean; Africa, India, and the Near East; and Asia, Australia, and the Pacific Ocean.

  15. Gemini Multi-Object Spectrograph Upgrades: Hamamatsu CCDs and AO

    NASA Astrophysics Data System (ADS)

    Roth, Katherine; Gimeno, G.; Murowinski, R.; Kleinman, S.; Trujillo, C. A.; Lai, O.

    2014-01-01

    The Gemini Multi-Object Spectrographs (GMOS) at both Gemini North and South have provided crucial access to longslit, MOS and IFU moderate resolution optical spectroscopy for the Gemini international partnership for over a decade. The interim installment of e2v deep depletion CCDs at GMOS-N in November 2011, providing enhanced red sensitivity, was the first major upgrade for either GMOS since the implementation of the Nod&Shuffle mode in 2002. We present plans to replace the original EEV detectors in GMOS-S with new Hamamatsu CCDs, extending wavelength coverage out beyond 1.03 microns. GMOS-N upgrade to Hamamatsu CCDs will follow the successful deployment on GMOS-S. With the extension of GMOS sensitivity further to long wavelengths it becomes even more attractive to extend the number of observing modes to include adaptive optics imaging and spectroscopy. As has already been demonstrated with GEMS/GMOS-S imaging, adaptive optics in the 0.8-1 micron wavelength regime on Gemini can effectively transform IQ70 conditions to IQ20 and more than double the spatial resolution over the natural seeing. We present plans to move forward with plans to enable GMOS + adaptive optics as a regular user mode at both sites.

  16. El Observatorio Gemini - Status actual

    NASA Astrophysics Data System (ADS)

    Levato, H.

    Se hace una breve descripción de la situación actual del Observatorio Gemini y de las últimas decisiones del Board para incrementar la eficiencia operativa. Se hace también una breve referencia al uso argentino del observatorio.

  17. Observations of Beta Pictoris b with the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Chilcote, J.; Graham, J.; Barman, T.; Fitzgerald, M.; Larkin, J.; Macintosh, B.; Bauman, B.; Burrows, A.; Cardwell, A.; De Rosa, R.; Dillon, D.; Doyon, R.; Dunn, J.; Erikson, D.; Gavel, D.; Goodsell, S.; Hartung, M.; Hibon, P.; Ingraham, P.; Kalas, P.; Konopacky, Q.; Maire, J.; Marchis, F.; Marley, M.; Mcbride, J.; Millar-Blanchaer, M.; Morzinski, K.; Norton, A.; Oppenheimer, B.; Palmer, D.; Patience, J.; Pueyo, L.; Rantakyro, F.; Sadakuni, N.; Saddlemyer, L.; Savransky, D.; Serio, A.; Soummer, R.; Sivaramakrishnan, A.; Song, I.; Thomas, S.; Wallace, K.; Wiktorowicz, S.; Wolff, S.

    2014-09-01

    Using the recently installed Gemini Planet Imager (GPI), we present measurements of the planetary companion to the nearby young star beta Pic. GPI is a facility class instrument located at Gemini South designed to image and provide low-resolution spectra of Jupiter sized, self-luminous planetary companions around young nearby stars. We present the current imaged spectrum and atmospheric models of the planet based upon GPI's R ˜50 integral field spectrograph. Further, we present a joint analysis of the GPI and NACO astrometry, and the Snellen et al. (2014) radial velocity measurement of beta Pic b that provides the first constraint on the argument of periastron, providing a causal link to the infalling, evaporating bodies.

  18. A Virtual Field Trip to the Gemini Observatory

    NASA Astrophysics Data System (ADS)

    Fisher, R. Scott; Michaud, P. D.

    2010-01-01

    Live from Gemini (LfG) is a virtual field trip using video conferencing technology to connect primary, secondary and post-secondary students with scientists and educators at the Gemini Observatory. As a pilot project, LfG is rapidly becoming one of the observatory's most often-requested educational programs for learners of all ages. The program aligns exceptionally well with national science (and technology) standards, as well as existing school curricula. This combination makes it easy for teachers to justify participation in the program, especially as the necessary video conferencing technology becomes ever more ubiquitous in classrooms and technology learning centers around the world. In developing and testing this pilot project, a programmatic approach and philosophy evolved that includes post-field-trip educational materials, multi-disciplinary subject matter (astronomy, geology, mathematics, meteorology, engineering and even language - the program is offered in Spanish from Gemini South in Chile), and the establishment of a personal connection and rapport with students. The presenters work to create a comfortable interaction despite the perceived technological barriers. The authors’ experiences with the LfG pilot project convince us that this model is viable for almost any astronomical observatory and should be considered by any dynamic, technology- and education-oriented facility.

  19. The Gemini Deep Planet Survey

    NASA Astrophysics Data System (ADS)

    Lafrenière, David; Doyon, René; Marois, Christian; Nadeau, Daniel; Oppenheimer, Ben R.; Roche, Patrick F.; Rigaut, François; Graham, James R.; Jayawardhana, Ray; Johnstone, Doug; Kalas, Paul G.; Macintosh, Bruce; Racine, René

    2007-12-01

    We present the results of the Gemini Deep Planet Survey, a near-infrared adaptive optics search for giant planets and brown dwarfs around 85 nearby young stars. The observations were obtained with the Altair adaptive optics system at the Gemini North telescope, and angular differential imaging was used to suppress the speckle noise of the central star. Typically, the observations are sensitive to angular separations beyond 0.5" with 5 σ contrast sensitivities in magnitude difference at 1.6 μm of 9.5 at 0.5", 12.9 at 1", 15.0 at 2", and 16.5 at 5". These sensitivities are sufficient to detect planets more massive than 2 MJ with a projected separation in the range 40-200 AU around a typical target. Second-epoch observations of 48 stars with candidates (out of 54) have confirmed that all candidates are unrelated background stars. A detailed statistical analysis of the survey results is presented. Assuming a planet mass distribution dn/dm~m-1.2 and a semimajor-axis distribution dn/da~a-1, the 95% credible upper limits on the fraction of stars with at least one planet of mass 0.5-13 MJ are 0.28 for the range 10-25 AU, 0.13 for 25-50 AU, and 0.093 for 50-250 AU; this result is weakly dependent on the semimajor-axis distribution power-law index. The 95% credible interval for the fraction of stars with at least one brown dwarf companion having a semimajor axis in the range 25-250 AU is 0.019+0.083-0.015, irrespective of any assumption on the mass and semimajor-axis distributions. The observations made as part of this survey have resolved the stars HD 14802, HD 166181, and HD 213845 into binaries for the first time. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National

  20. Gemini surfactants with a disaccharide spacer.

    PubMed

    Menger, F M; Mbadugha, B N

    2001-02-01

    A gemini surfactant is an amphiphile possessing (in sequence) the following: hydrocarbon tail/polar group/spacer/polar group/hydrocarbon tail. Widespread interest in geminis has emerged recently from both industrial and academic laboratories. In the present contribution, two related families of geminis have been synthesized, both with trehalose, a disaccharide, as a polar spacer. One family, Series-A, is nonionic and has amide groups separating the long chains from the trehalose spacer. The other family, Series-B, has quaternary ammonium ions connecting the long chains to the trehalose spacer. It was found that Series-A geminis are water insoluble despite the two amides and multiple hydroxyls. When hydrated or extruded, these geminis form microscopically visible vesicular and tubular structures above their transition temperatures (which were determined calorimetrically). Insoluble monomolecular films, constructed from these geminis, have interfacial areas that are dominated by the sugar spacer although intermolecular chain/chain interactions seem to stabilize the films. Thus, the behavior of Series-A geminis in many ways parallels that of phospholipids and simple double-chain surfactants. It is as if the trehalose is less of a spacer than a large but conventional headgroup. In contrast, cationic Series-B geminis are water soluble and form micelles with critical micelle concentrations an order of magnitude lower than that of corresponding conventional surfactants. Molecular modeling using the Amber force field explains the difference in properties between the two families of geminis. Series-A are tubular in shape and thus prefer bilayer packing as do other amphiphiles in which the headgroups are similar in width to the sum of the tail diameters. Series-B geminis are conical-shaped and pack more readily into spherical micelles. This work entails synthesis, tensiometry, conductance, microscopy, surface balance studies, calorimetry, light scattering, and molecular

  1. Gemini spectra of 12000 K white dwarf stars

    NASA Astrophysics Data System (ADS)

    Kepler, S. O.; Castanheira, B. G.; Costa, A. F. M.; Koester, D.

    2006-11-01

    We report signal-to-noise ratio (S/N) ~= 100 optical spectra for four DA white dwarf stars acquired with the GMOS spectrograph of the 8-m Gemini north telescope. These stars have 18 < g < 19 and are around Teff ~ 12000 K, where the hydrogen lines are close to maximum. Our purpose is to test if the effective temperatures and surface gravities derived from the relatively low-S/N ( ~ 21) optical spectra acquired by the Sloan Digital Sky Survey through model atmosphere fitting are trustworthy. Our spectra range from 3800 to 6000 Å, therefore including Hβ to H9. The H8 line was only marginally present in the SDSS spectra, but is crucial to determine the gravity. When we compare the values published by Kleinman et al. and Eisenstein et al. with our line-profile technique (LPT) fits, the average differences are: ΔTeff ~= 320 K, systematically lower in the SDSS, and Δ log g ~= 0.24 dex, systematically larger in the SDSS. The correlation between the gravity and the effective temperature can only be broken at wavelengths bluer than 3800 Å. The uncertainties in Teff are 60 per cent larger, and in log g larger by a factor of 4, than the internal uncertainties of Kleinman et al. and Eisenstein et al. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil) and CONICET (Argentina). E-mail: kepler@if.ufrgs.br

  2. Characterizing Transiting Exoplanet Atmospheres with Gemini/GMOS: First Results

    NASA Astrophysics Data System (ADS)

    Huitson, Catherine; Desert, Jean-Michel; Bean, Jacob; Fortney, Jonathan J.; Stevenson, Kevin B.; Bergmann, Marcel

    2015-01-01

    We present the first results from a 4-year ground-based survey of nine transiting exoplanet atmospheres. The program uses the Multi-Object Spectrograph (GMOS) on both Gemini north and south to repetitively measure transit lightcurves of individual exoplanets at high spectrophotometric precision. I will present the first results from this program. We attain photometric precisions per spectral bin of 200-600 ppm. Such precision enables us to construct transmission spectra of hot Jupiters. These transmission spectra reveal the dominant upper-atmosphere absorbers in the optical bandpass. Our overarching goal is to understand the prevalence and formation of high altitude clouds and hazes, and other important atmospheric constituents.

  3. Gemini

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Twins; abbrev. Gem, gen. Geminorum; area 514 sq. deg.) A northern zodiacal constellation which lies between Auriga and Canis Minor, and culminates at midnight in early January. It represents Castor and Pollux, the twin sons of Leda, Queen of Sparta, in Greek mythology, whose brotherly love was rewarded by a place among the stars. Its brightest stars were cataloged by Ptolemy (c. AD 100-175) ...

  4. Schirra, Stafford and Gemini on Deck

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Astronaut Walter H. Schirra Jr. (on right), Command pilot, climbs from his Gemini VI spacecraft as he and Astronaut Thomas P. Stafford (not in view) arrive aboard the aircraft carrier U.S.S. Wasp. They are assisted by various McDonell Douglas technicians. The Gemini VI spacecraft splashed down in the western Atlantic recover area at 10:29 a.m. (EST) December 16, 1965, after a successful 25 hr. 52 minute mission in space.

  5. Point spread function reconstruction on the Gemini Canopus bench

    NASA Astrophysics Data System (ADS)

    Gilles, Luc; Neichel, Benoit; Veran, Jean-Pierre; Ellerbroek, Brent

    2013-12-01

    This paper discusses an open loop, single-conjugate, point spread function reconstruction experiment performed with a bright calibration source and synthetic turbulence injected on the ground-level deformable mirror of the Multi Conjugate Adaptive Optics Canopus bench at Gemini South. Time histories of high-order Shack-Hartmann wavefront sensor slopes were recorded on the telemetry circular buffer, and time histories of short exposure K-band point spread functions with and without turbulence injected were recorded with the Gemini South Adaptive Optics Imager. We discuss the processing of the data and show that the long exposure background- and tip/tilt-removed turbulence image can be reconstructed at a percent level accuracy from the tip/tilt-removed de-noised wavefront sensor slope covariance matrix and from the long exposure background- and tip/tilt-removed static image. Future experiments are planned with multiple calibration sources at infinite and finite range and turbulence injected on 2 deformable mirrors, aiming at validating the recently published point spread function reconstruction algorithm [Gilles et. al. Appl. Opt. 51, 7443 (2012)] for closed loop laser guide star multi-conjugate adaptive optics.

  6. The Gemini NICI Planet-Finding Campaign: Deep Imaging of Stars in the Solar Neighborhood

    NASA Astrophysics Data System (ADS)

    Biller, Beth A.; Wahhaj, Z.; Liu, M.; Chun, M.; Close, L.; Ftaclas, C.; Hartung, M.; Hayward, T.; Nielsen, E.; Toomey, D.; NICI Planet-Finding Campaign Team

    2010-01-01

    The novel Near Infrared Coronagraphic Imager (NICI) on the 8-m Gemini South telescope combines a number of techniques to attenuate starlight and suppress superspeckles for direct detection of exoplanets: 1) Lyot coronagraphic imaging, 2) dual channel imaging for Spectral Differential Imaging (SDI) and 3) operation in a fixed Cassegrain rotator mode for Angular Differential Imaging (ADI). The combination of these techniques allows unprecedented contrasts of dmag > 14 (median value) at 1" in H band. We are currently conducting a 50 night planet-finding campaign using NICI. Although the majority of our survey targets are young (<300 Myr, so as to catch young planets while they are still self-luminous), we are also observing a subset of nearby stars in the immediate solar neighborhood. While these objects are old (and hence, planetary companions will be faint), they are still desirable targets for planet searches due to the excellent physical resolution possible around these stars. Additionally, their large proper motions also mean that planet candidates can be quickly confirmed. NICI is the first instrument with achieved star-planet contrasts high enough to image supergiant planets around these stars (M > 10 MJup). Here, we report on results from observations of 3 such nearby stars. At respective distances of 1.39 pc, 2.35 pc, and 3.8 pc, Proxima Centauri, Wolf 359, and Luyten's Star are the 1st, 3rd, and 22nd closest stars to the Sun. While our search yielded numerous candidate companions, especially around Proxima Centauri, all of these candidates were found to be background in second epoch observations.

  7. Gemini 11 prime and back-up crews at Gemini Mission Simulator at Cape Kennedy

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Gemini 11 prime and back-up crews at Gemini Mission Simulator at Cape Kennedy, Florida. Left to right are Astronauts William A. Anders, back-up crew pilot; Richard F. Gordon Jr., prime crew pilot; Charles Conrad Jr. (foot on desk), prime crew command pilot; and Neil A. Armstrong, back-up crew command pilot.

  8. Women Astronomers at Gemini: A Success Story

    NASA Astrophysics Data System (ADS)

    Rodgers, Bernadette; Jorgensen, I.; Barker, N.; Edwards, M.; Trancho, G.

    2010-01-01

    Gemini Observatory has been very successful at attracting, hiring and retaining female Scientists. We present data on the growth of the scientific staff since the start of the Observatory, and science fellow recruiting from 2006-2008. At Gemini 31% of the Science Staff holding PhDs are female compared with 13.9% within the United States. The Science Management is 75% female, as is 50% of the Gemini Directorate. This critical mass of female representation within the science staff and management appears to have had a positive effect on female recruitment and hiring. The science fellow recruitment during the past 3 years has attracted 21-38% female applicants and 57% of new hires during this period have been female scientists. Perhaps even more significant, the retention rate of female science staff at Gemini is 88%, compared to 64% for male science staff. There are likely many factors that contribute to this success, but the conclusion is that Gemini has earned a reputation in the scientific community as a place where female scientists are valued and can be successful.

  9. 1.8-M solar telescope in China: the CLST

    NASA Astrophysics Data System (ADS)

    Rao, Changhui; Gu, Naiting; Zhu, Lei; Liu, Yangyi; Huang, Jinlong; Li, Cheng; Cheng, Yuntao; Cao, Xuedong; Zhang, Ming; Zhang, Lanqiang; Liu, Hong; Wan, Yongjian; Xian, Hao; Ma, Wenli; Bao, Hua; Zhang, Xiaojun; Guan, Chunlin; Chen, Donghong; Li, Mei

    2014-07-01

    For better understanding and forecasting of the solar activity and the corresponding impacts human technologies and life on earth, the high resolution observations for Sun are needed. The Chinese Large Solar Telescope (CLST) with 1.8 m aperture is being built. The CLST is a classic Gregorian configuration telescope with open structure, alt-azimuth mount, retractable dome, and a large mechanical de-rotator. The optical system with all reflective design has the field of view of larger than 3 arc-minute. The 1.8 m primary mirror is a honeycomb sandwiches fused silica lightweight mirror with ULE material and active cooling. The adaptive optics system will be developed to provide the capability for diffraction limited observations at visible wavelengths. The CLST design and development phase began in 2011 and 2012 respectively. We plan for the CLST's starting of commission in 2017. A multi-wavelength tomographic imaging system with seven wavelengths range from visible to near-infrared wavelength is considered as the first light scientific instruments. In this paper the main system configuration and the corresponding post focal instruments are described. Furthermore, the latest progress and current status of the CLST are also reported.

  10. Integral field spectroscopy with the Gemini Near-Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Allington-Smith, Jeremy R.; Dubbeldam, Cornelis M.; Content, Robert; Dunlop, Colin J.; Robertson, David J.; Elias, Jay; Rodgers, Bernadette; Turner, James E.

    2004-09-01

    The Astronomical Instrumentation Group (AIG) of the University of Durham has recently completed an integral field unit (IFU) for use on the Gemini-South telescope with the Gemini Near-Infrared Spectrograph (GNIRS) built by the National Optical Astronomy Observatories (NOAO, USA). When the IFU is deployed remotely inside the instrument cryostat, GNIRS is converted into an integral field spectrograph with a field of 5 × 3 arcsec2 and spatial sampling of 0.15 × 0.15 arcsec2, optimised for 1-2.5μm but operable up to 5μm. We present summaries of the design and construction and results from laboratory testing. We also show results obtained at the telescope where a throughput of 90% was measured at 2.5μm, and show that this is consistent with predictions of a simple model where surface scattering is the dominant loss mechanism. The throughput data are well fit by the roughness measured in the laboratory. Finally, we show a few examples of astrophysical data from the commissioning run in April 2004.

  11. The Astrometric Calibration of the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Tran, Debby; Konopacky, Quinn; GPIES Collaboration

    2016-06-01

    The Gemini Planet Imager (GPI), housed on the 8-meter Gemini South telescope in Chile, is an instrument designed to detect Jupiter-like extrasolar planets by direct imaging. It relies on adaptive optics to correct the effects of atmospheric turbulence, along with an advanced coronagraph and calibration system. One of the scientific goals of GPI is to measure the orbital properties of the planets it discovers. Because these orbits have long periods, precise measurements of the relative position between the star and the planet (relative astrometry) are required. In this poster, I will present the astrometric calibration of GPI. We constrain the plate scale and orientation of the camera by observing different binary star systems with both GPI and another well-calibrated instrument, NIRC2, at the Keck telescope in Hawaii. We measure their separations with both instruments and use that information to calibrate the plate scale. By taking these calibration measurements over the course of one year, we have measured the plate scale to 0.05% and shown that it is stable across multiple epochs. I will also discuss our effort to correct for optical distortion using pinhole masks in the laboratory.

  12. Summary analysis of the Gemini entry aerodynamics

    NASA Technical Reports Server (NTRS)

    Whitnah, A. M.; Howes, D. B.

    1972-01-01

    The aerodynamic data that were derived in 1967 from the analysis of flight-generated data for the Gemini entry module are presented. These data represent the aerodynamic characteristics exhibited by the vehicle during the entry portion of Gemini 2, 3, 5, 8, 10, 11, and 12 missions. For the Gemini, 5, 8, 10, 11, and 12 missions, the flight-generated lift-to-drag ratios and corresponding angles of attack are compared with the wind tunnel data. These comparisons show that the flight generated lift-to-drag ratios are consistently lower than were anticipated from the tunnel data. Numerous data uncertainties are cited that provide an insight into the problems that are related to an analysis of flight data developed from instrumentation systems, the primary functions of which are other than the evaluation of flight aerodynamic performance.

  13. The Gemini Instrument Feasibilities Studies project

    NASA Astrophysics Data System (ADS)

    Hibon, Pascale; Goodsell, Stephen J.; Hardie, Kayla

    2015-01-01

    The Gemini Instrument Feasibilities Studies (GIFS) project is part of a program that will provide a number of community-created science-driven instrumentation design study reports and presentations to the observatory, conforming to a number of desired principles.By the time of the AAS, Gemini will have received a number of proposals and will be evaluating them shortly afterwards with the expectation of placing 3 or more feasibility study contracts based on a facility instrument costing between USD 8,000,000 and USD 12,000,000. These instrument studies will provide synergies with new capabilities coming online (e.g. LSST, JWST, ALMA, etc)Following the project, Gemini together with the Gemini Science and Technical Advisory Committee (STAC) and input from the wider community will decide on the top-level instrument requirements for the next facility instrument (Gen4#3) and launch a targeted Request for Proposals to design, build, test and deliver a suitable instrument. Gemini expects to release an RfP for Gen4#3 in Q4 2015.Each feasibility study will include fully developed science case(s), optical, mechanical, electronic and software design elements at the conceptual level as needed to demonstrate the technical viability. In particular, each design study will thoroughly identify and mitigate key risks.Each study team will present a status summary presentation at the 2015 Meeting on the Science and Future of Gemini held in Toronto in June 2015. The final GIFS reports and presentations are expected in Sept 2015.We will discuss the status of GIFS and the currently plans for Gen4#3.

  14. Exploración con GEMINI-GMOS del sistema de cúmulos globulares de NGC 5044

    NASA Astrophysics Data System (ADS)

    Faifer, F. R.; Cellone, S. A.; Smith Castelli, A. V.; Bassino, L. P.; Forte, J. C.

    We present preliminary results of the first photometric study of the globular cluster system associated to the elliptical galaxy NGC 5044, the dominant object in the homonymous group. These results are based on data recently (semester 2009A) obtained with the Multi Object Spectrograph GMOS at the Gemini South telescope. FULL TEXT IN SPANISH

  15. Arabian Peninsula and northeast Africa as seen from Gemini 11 spacecraft

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Arabian Peninsula (on left) and northeast Africa (on right) as seen from the Gemini 11 spacecraft at an altitude of 340 nautical miles during its 27th revolution of the earth, looking southeast. Saudia Arabia, South Arabia, Yemen and Aden Protectorate are at left. At bottom right is Ethiopia. French Somaliland is in center on right shore. Somali is at upper right. Body of water at bottom is Red Sea. Gulf of Aden is in center; and at top left is Indian Ocean.

  16. Enhancement of soil retention for phenanthrene in binary cationic gemini and nonionic surfactant mixtures: characterizing two-step adsorption and partition processes through experimental and modeling approaches.

    PubMed

    Zhao, Shan; Huang, Gordon; An, Chunjiang; Wei, Jia; Yao, Yao

    2015-04-01

    The enhancement of soil retention for phenanthrene (PHE) through the addition of a binary mixture of cationic gemini (12-2-12) and nonionic surfactants (C12E10) was investigated. The maximum apparent sorption coefficient Kd(*) reached 4247.8 mL/g through the addition of mixed 12-2-12 gemini and C12E10 surfactants, which was markedly higher than the summed individual results in the presence of individual 12-2-12 gemini (1148.6 mL/g) or C12E10 (210.0 mL/g) surfactant. However, the sorption of 12-2-12 gemini was inhibited by the increasing C12E10 dose; and a higher initial 12-2-12 gemini dose showed a higher "desorption" rate. The present study also addressed the sorption behavior of the single 12-2-12 gemini surfactant at the soil/aqueous interface. The sorption isotherm was divided into two steps to elucidate the sorption process; and the sorption schematics were proposed to elaborate the growth of surfactant aggregates corresponding to the various steps of the sorption isotherm. Finally, a two-step adsorption and partition model (TAPM) was developed to simulate the sorption process. Analysis of the equilibrium data indicated that the sorption isotherms of 12-2-12 gemini fitted the TAPM model better. Thermodynamic calculations confirmed that the 12-2-12 gemini sorption at the soil/aqueous interface was spontaneous and exothermic from 288 to 308K. PMID:25576782

  17. Geo-Engineering through Internet Informatics (GEMINI)

    SciTech Connect

    Doveton, John H.; Watney, W. Lynn

    2003-03-06

    The program, for development and methodologies, was a 3-year interdisciplinary effort to develop an interactive, integrated Internet Website named GEMINI (Geo-Engineering Modeling through Internet Informatics) that would build real-time geo-engineering reservoir models for the Internet using the latest technology in Web applications.

  18. Structural Design Considerations for an 8-m Space Telescope

    NASA Technical Reports Server (NTRS)

    Arnold, William R. Sr.; Stahl, H. Philip

    2009-01-01

    NASA's upcoming ARES V launch vehicle, with its' immerse payload capacities (both volume and mass) has opened the possibilities for a whole new paradigm of space observatories. It becomes practical to consider a monolith mirror of sufficient size to permit significant scientific advantages, both in collection area and smoothness or figure at a reasonable price. The technologies and engineering to manufacture and test 8 meter class monoliths is mature, with nearly a dozen of such mirrors already in operation around the world. This paper will discuss the design requirements to adapt an 8m meniscus mirror into a Space Telescope System, both launch and operational considerations are included. With objects this massive and structurally sensitive, the mirror design must include all stages of the process. Based upon the experiences of the Hubble Space Telescope, testing and verification at both component and integrated system levels are considered vital to mission success. To this end, two different component level test methods for gravity sag (the so call zero- gravity simulation or test mount) are proposed, with one of these methods suitable for the full up system level testing as well.

  19. Observations Of The LCROSS Impact With NIFS On The Gemini North Telescope

    NASA Astrophysics Data System (ADS)

    Roth, Katherine; Stephens, A. W.; Trujillo, C. A.; McDermid, R. M.; Woodward, C. E.; Walls, B. D.; Coulson, D. M.; Matulonis, A. C.; Ball, J. G.; Wooden, D. H.

    2010-01-01

    The Lunar CRater Observation and Sensing Satellite (LCROSS) Centaur rocket impacted a permanently shadowed crater near the south pole of the Moon at 11:31 UTC 2009 October 09. Gemini, one of several telescopes in a coordinated network observing the impact, conducted observations using NIFS to obtain 3D K-band imaging spectroscopy to detect water ice in the ejected plume of material. The spectral slope of the NIFS data can constrain the grain size and height distribution as the plume evolves, measuring the total mass and the water ice concentration in the plume. These observations provided an engineering challenge for Gemini, including the need to track non-sidereal with constantly changing track rates and guide on small bright moon craters, in order to keep the impact site within the NIFS field-of-view. High quality images taken by GMOS-N, NIRI and the acquisition camera during engineering periods at specific lunar libration and illumination were also used by the LCROSS ground based observing team to supplement slit positioning and offset plans for other ground based observatories. LCROSS mission support and engineering has resulted in improved telescope functionality for non-sidereal targets, including the ability to upload and import target ephemerides directly into the TCS, starting in semester 2010B. In this poster we present the engineering results and observing improvements which will facilitate enhanced user capabilities of the Gemini telescopes arising from the intensive LCROSS support challenge. Gemini Observatory is operated by AURA, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the NSF (United States), the STFC (United Kingdom), the NRC (Canada), CONICYT (Chile), the ARC (Australia), Ministério da Ciência e Tecnologia (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). In part this research was supported by NASA through contracts to SWRI and NSF grant AST-0706980 to the U

  20. Visible Spectroscopic Observation Of Asteroid 162173 (1999ju3) With The Gemini-s Telescope

    NASA Astrophysics Data System (ADS)

    Sugita, Seiji; Kuroda, D.; Kameda, S.; Hasegawa, S.; Kamata, S.; Abe, M.; Ishiguro, M.; Takato, N.; Yoshikawa, M.

    2012-10-01

    Asteroid 162173 (1999JU3; hereafter JU3) is the target of the Hayabusa-2 mission. Its visible reflectance spectra have been observed a few times [1,2], and obtained spectra exhibit a wide variety of spectral patterns ranging from a spectra with absorption in the UV region (May 1999) to a flat spectrum with a faint broad absorption centered around 0.6 microns (September 2007) and that with UV absorption and strong broad absorption centered around 0.7 micron (July 2007). The apparent large spectral variation may be due to variegation on the asteroid surface. Such variegation would make a large influence on remote sensing strategy for Hayabusa-2 before its sampling operations. In order to better constraint the spectral properties of JU3, we conducted visible spectroscopic observations at the GEMINI-South observatory 8.1-m telescope with the GMOS instrument. We could obtain three different sets of data in June and July 2012. Although the JU3 rotation phases of two of the observation are close to each other, the other is about 120 degrees away from the two. Our preliminary analyses indicate that these three spectra are slightly reddish but generally flat across the observed wavelength range (0.47 - 0.89 microns). The observed flat spectra are most similar to the spectrum obtained in September 2007, which probably has the highest signal-to-noise ratio among the previous three spectra. This result suggests that material with a flat spectrum probably covers a dominant proportion of the JU3 surface and that the other two types of previously obtained spectra may not cover a very large fraction of the JU3 surface. [1] Binzel, R. P. et al. (2001) Icarus, 151, 139-149; [2] Vilas, F. (2008) AJ, 135, 1101-1105.

  1. User interface for the control of the Gemini Telescopes

    NASA Astrophysics Data System (ADS)

    Smith, Steven S.; Gillies, Kim K.

    1997-09-01

    A discussion of the interactive operator user interface developed for the Gemini 8-m Telescopes is presented. Topics include the use of a layered synthesized view of the area of interest on the sky, a data driven approach to the control of the subsystems, and an adaptive view on the health of those subsystems. The synthesized view utilizes information from pre-existing databases; guide, wavefront and scientific detector image data; as well as operating and performance limits. This information is presented to the user in layers, with each layer containing an observer, subsystem or other logically oriented view. The ability to control which layers are presented, as well as which parameters are directly modifiable is vested in both the user and the configuration software. Implementing this above a data driven control interface encourages the use of observing templates. Exhaustive parameter control with parallel realization in the lower level mechanisms results in fast, fine grained and repeatable control. Combining the major control interfaces, each with a different view of the desired behavior, error in behavior, and possible corrections allows the operator to spend more time optimizing observations, rather than setting up equipment. Maximizing time with quality light falling on the science detectors is a primary goal.

  2. Gemini helium closed cycle cooling system

    NASA Astrophysics Data System (ADS)

    Lazo, Manuel; Galvez, Ramon; Rogers, Rolando; Solis, Hernan; Tapia, Eduardo; Maltes, Diego; Collins, Paul; White, John; Cavedoni, Chas; Yamasaki, Chris; Sheehan, Michael P.; Walls, Brian

    2008-07-01

    The Gemini Observatory presents the Helium Closed Cycle Cooling System that provides cooling capacity at cryogenic temperatures for instruments and detectors. It is implemented by running three independent helium closed cycle cooling circuits with several banks of compressors in parallel to continuously supply high purity helium gas to cryocoolers located about 100-120 meters apart. This poster describes how the system has been implemented, the required helium pressures and gas flow to reach cryogenic temperature, the performance it has achieved, the helium compressors and cryocoolers in use and the level of vibration the cryocoolers produce in the telescope environment. The poster also describes the new technology for cryocoolers that Gemini is considering in the development of new instruments.

  3. Final A&T stages of the Gemini Planet Finder

    NASA Astrophysics Data System (ADS)

    Hartung, Markus; Macintosh, Bruce; Poyneer, Lisa; Savransky, Dimitri; Gavel, Donald; Palmer, Dave; Thomas, Sandrine; Dillon, Daren; Chilcote, Jeffrey; Ingraham, Patrick; Sadakuni, Naru; Wallace, Kent; Perrin, Marshall; Marois, Christian; Maire, Jerome; Rantakyro, Fredrik; Hibon, Pascale; Saddlemyer, Les; Goodsell, Stephen

    2013-12-01

    The Gemini Planet Finder (GPI) is currently in its final Acceptance & Testing stages at the University of Santa Cruz, California. GPI is an XAO system based on a tweeter & woofer architecture (43 & 9 actuators across the pupil), with the tweeter being a Boston Michromachines 64^2 MEMS device. The XAO AO system is tightly integrated with a Lyot apodizing coronagraph. Acceptance has started in February 2013. After the conclusive acceptance review shipment is scheduled mid 2013 to ensure readiness for commissioning at the Gemini South telescope on Cerro Pachon, Chile, end of 2013, matching the summer window of the southern hemisphere. According to current estimates the 3 year (~800 allocated hours) planet finding campaign might discover, image, and spectroscopically analyze 20 to 40 new exo-planets.Final acceptance testing of the integrated instrument can always emerge a number of unforeseen challenges as we are eventually using cold chamber and flexure rig installations. The latest developments will be reported. Also, we will give an overview of GPI's lab performance, the interplay between subsystems such as the calibration unit (CAL) with the AO bench. (The CAL principal purpose is to maintain a clean and centered XAO PSF on the coronagraph.) We report on-going optimizations on the AO controler loop to filter vibrations and last but not least achieved contrast performance applying speckle nulling. Furthermore, we will give an outlook of possible but challenging future upgrades as the implementation of a predictive controler or exchanging the conventional 48x48 SH WFS with a pyramid. With the ELT area arising, GPI will proof as a versatile and path-finding testbed for AO technologies on the next generation of ground-based telescopes.

  4. Gemini 4 Recovery with Green Marker Dye

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Overhead view of the Gemini 4 spacecraft showing the yellow flotation collar used to stabilize the spacecraft in choppy seas. The green marker dye is highly visible from the air and is used as a locating aid. A crewmember is being hoisted aboard a U.S. Navy helicopter during recovery operations following the successful four-day, 62 revolution mission highlighted by Ed White's space walk.

  5. SN 1987A after 18 Years: Mid-Infrared GEMINI and SPITZER Observations of the Remnant

    NASA Technical Reports Server (NTRS)

    Bouchet, Patrice; Dwek, Eli; Danziger, John; Arendt, Richard G.; DeBuizer, James M.; Park, Sangwook; Suntzeff, Nicholas B.; Kirshner, Robert P.; Challis, Peter

    2007-01-01

    We present high resolution 11.7 and 18.3 micron mid-IR images of SN 1987A obtained on day 6526 since the explosion with the Thermal-Region Camera and Spectrograph (T-ReCS) attached to the Gemini South 8m telescope. The 11.7 micron flux has increased significantly since our last observations on day 6067. The images clearly show that all the emission arises from the equatorial ring (ER). Nearly contemporaneous spectra obtained on day 6184 with the MIPS at 24 micron, on day 6130 with the IRAC in 3.6- 8 micron region, and on day 6190 with the IRS in the 12-37 micron instruments on board the Spitzer Space Telescope's show that the emission consists of thermal emission from silicate dust that condensed out in the red giant wind of the progenitor star. The dust temperature is 1662(sup +18) (sub -12) K, and the emitting dust mass is (2.6(sup +2.0 (sub -1.4)) x 10 (exp -6) M(solar). Lines of [Ne II] 12.82 micron and [Ne III] 15.56 pm are clearly present in the Spitzer spectrum, as well as a weak [Si II] 3 34.8 micron line. We also detect two lines near 26 micron which we tentatively ascribe to [Fe II] 25.99 pm and [0 IV] 25.91 micron. Comparison of the mid-IR Gemini 11.7 micron image with X-ray images obtained by Chandra, UV-optical images obtained by HST, and radio synchrotron images obtained by the ATCA show generally good correlation of the images across all wavelengths. Because of the limited resolution of the mid-IR images we cannot uniquely determine the location. or heating mechanism of the dust giving rise to the emission. The dust could be collisionally heated by the X-ray emitting plasma, providing a unique diagnostic of plasma conditions. Alternatively, the dust could be radiatively heated in the dense UV-optical knots that are overrun by the advancing supernova blast wave. In either case the dust-to-gas mass ratio in the circumstellar medium around the supernova is significantly lower than that in the general interstellar medium of the LMC, suggesting either a

  6. Gemini 10 prime crew during post flight press conference

    NASA Technical Reports Server (NTRS)

    1966-01-01

    At podium during Gemini 10 press conference are (l-r) Dr. Robert C. Seamans, Astronauts John Young and Michael Collins and Dr. Robert R. Gilruth (39895); Wide angle view of the Manned Spacecraft Center (MSC) News Center during the Gemini 10 prime crew post flight press conference (38786); Astronaut Young draws diagram on chalk board of tethered extravehicular activity accomplished during Gemini 10 flight (39897).

  7. Portrait of Gemini 11 prime and backup crews

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Portrait of Gemini 11 prime and backup crews. Seated are the Gemini 11 prime crewmembers (l.-r.) Astronauts Richard F. Gordon Jr., prime crew pilot, and Charles Conrad Jr., prime crew command pilot. Standing are (l.-r.) Astronauts William A. Anders, backup crew pilot, and Neil Armstrong, backup crew command pilot. They are in their space suits next to a mock-up of the Gemini spacecraft.

  8. Gemini 8 prime crew and other astronauts at prelaunch breakfast

    NASA Technical Reports Server (NTRS)

    1966-01-01

    The Gemini 8 prime crew, along with several fellow astronauts, have a hearty breakfast of steak and eggs on the morning of the Gemini 8 launch. Seated clockwise around the table, starting at lower left, are Donald K. Slayton, Manned Spaceflight Center (MSC) Assistant Director for Flight Crew Operations; Astronaut Neil A. Armstrong, Gemini 8 command pilot; Scientist-Astronaut F. Curtis Michel; Astronaut R. Walter Cunningham; Astronaut Alan B. Shepard Jr. (face obscured), Chief, MSC Astronaut Office; Astronaut David R. Scott, Gemini 8 pilot; and Astronaut Roger B. Chaffee.

  9. The Transformation of Observatory Newsletters - A Gemini Perspective

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoyu

    2015-08-01

    Astronomical observatories publish newsletters to communicate the observatory’s new discoveries and activities with its user communities, funding agencies, and general public. Gemini Observatory started publishing the newsletter in March 1992. Over the years, it transformed from a no-frills black and white publication to a full-color magazine type newsletter with a special name “GeminiFocus”. Since 2012, the contents of GeminiFocus moved from print to digital with an additional print issue of the Year in Review. The newsletter transformation is in sync with the rapid development of the internet technologies. We discuss here the evolvement of Gemini newsletter and the lessons learned.

  10. Gemini Observatory's Innovative Education and Outreach for 2006 and Beyond

    NASA Astrophysics Data System (ADS)

    Harvey, J.

    2006-08-01

    Gemini Observatory, in preparation for its bold informal science plan for the next five years, is making an exciting effort to bring education outside our typical borders and into our partner countries and beyond. We will introduce some of the innovative outreach programs that have been highly successful in Hawaii/US and explain how Gemini's PIO efforts will further develop new concepts as we move forward in our next phase of education and outreach. In this presentation we will highlight a few of Gemini's highly successful initiatives: - Stars Over Mauna Kea Newspaper Tabloid, the second bi-annual publication giving a comprehensive review of astronomy on Mauna Kea - Hawaii's Journey through the Universe program which has been touted as the flagship program in the US. I will discuss how we envision introducing this novel education approach to our seven partner countries. - StarTeachers International teacher's exchange - The newly developed partnership between the Imiloa Astronomy Education Center's planetarium and Gemini's StarLab programs. - Extension of our Family Astro programs internationally. - Gemini's student "Time on the Telescope" mentor program. - "Gemini Live," a videoconference between our astronomers at the control room of Gemini and classrooms around the world. - The unique partnership created between Gemini's PIO department and the Department of Education in Hawaii, and how other astronomical facilities could play a prominent role in their state's/country's informal science education development.

  11. Portrait of the Gemini 8 prime and backup crews

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Portrait of the Gemini 8 prime and backup crews. Astronauts David R. Scott (left), pilot, and Astronaut Neil A. Armstrong, command pilot, are the prime crew of the Gemini 8 mission. Backup crew (left to right, standing), are Astronauts Richard F. Gordon Jr., pilot, and Charles Conrad Jr., command pilot.

  12. Development and Commissioning of the Integral Field Spectrograph for the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Chilcote, Jeffrey K.; Larkin, J. E.; Planet Imager instrument, Gemini; science Teams

    2014-01-01

    The Gemini Planet Imager (GPI) is one of a new generation of instruments being built to directly image extrasolar planets in the outer solar systems of young main sequence stars. By combining a 1700-actuactor adaptive optics system, an apodized-pupil Lyot coronagraph, a precision interferometric infrared wavefront sensor, and an integral field spectrograph (IFS), GPI’s goal is more than an order of magnitude improvement in contrast compared to existing high contrast systems. This presentation focuses on the performance and characterization of the GPI IFS which is based on concepts from the OSIRIS instrument employed at Keck. Like OSIRIS, the IFS utilizes an infrared transmissive lenslet array to sample an approximate 2.7 x 2.7 arcsecond field of view at the diffraction limit of the Gemini Telescopes. The IFS provides over 36,000 simultaneous low-resolution (R ~ 45) spectra across five bands between 1 and 2.5μm. Alternatively, the dispersing element can be replaced with a Wollaston prism to provide broadband polarimetry of the same five filter bands. The IFS construction was based at the University of California, Los Angeles in collaboration with the Université de Montreal, Immervision and Lawrence Livermore National Laboratory. The IFS was integrated with the other components of GPI in the fall of 2011. GPI has recently finished Integration & Testing at the University of California, Santa Cruz, and has been shipped to Gemini South where it is undergoing post delivery acceptance testing.

  13. Gemini-IFU Spectroscopy of HH 111

    NASA Astrophysics Data System (ADS)

    Cerqueira, A. H.; Vasconcelos, M. J.; Raga, A. C.; Feitosa, J.; Plana, H.

    2015-03-01

    We present new optical observations of the Herbig-Haro (HH) 111 jet using the Gemini Multi Object Spectrograph in its Integral Field Unit mode. Eight fields of 5\\prime\\prime × 3\\buildrel{\\prime\\prime}\\over{.} 5 have been positioned along and across the HH 111 jet, covering the spatial region from knot E to L in HH 111 (namely, knots E, F, G, H, J, K, and L). We present images and velocity channel maps for the [O i] 6300+6360, Hα, [N ii] 6548+6583, and [S ii] 6716+6730 lines, as well as for the [S ii] 6716/6730 line ratio. We find that the HH 111 jet has an inner region with lower excitation and higher radial velocity, surrounded by a broader region of higher excitation and lower radial velocity. Also, we find higher electron densities at lower radial velocities. These results imply that the HH 111 jet has a fast, axial region with lower velocity shocks surrounded by a lower velocity sheath with higher velocity shocks. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  14. Self-Assembly of Gemini Surfactants

    NASA Astrophysics Data System (ADS)

    Yethiraj, Arun; Mondal, Jagannath; Mahanthappa, Mahesh

    2013-03-01

    The self-assembly behavior of Gemini (dimeric or twin-tail) dicarboxylate disodium surfactants is studied using molecular dynamics simulations. This gemini architecture, in which two single tailed surfactants are joined through a flexible hydrophobic linker, has been shown to exhibit concentration-dependent aqueous self-assembly into lyotropic phases including hexagonal, gyroid, and lamellar morphologies. Our simulations reproduce the experimentally observed phases at similar amphiphile concentrations in water, including the unusual ability of these surfactants to form gyroid phases over unprecedentedly large amphiphile concentration windows. We demonstrate quanitative agreement between the predicted and experimentally observed domain spacings of these nanostructured materials. Through careful conformation analyses of the surfactant molecules, we show that the gyroid phase is electrostatically stabilized related to the lamellar phase. By starting with a lamellar phase, we show that decreasing the charge on the surfactant headgroups by carboxylate protonation or use of a bulkier tetramethyl ammonium counterion in place of sodium drives the formation of a gyroid phase.

  15. First light of the Gemini Planet Imager

    DOE PAGES

    Macintosh, Bruce; Graham, James R.; Ingraham, Patrick; Konopacky, Quinn; Marois, Christian; Perrin, Marshall; Poyneer, Lisa; Bauman, Brian; Barman, Travis; Burrows, Adam S.; et al

    2014-05-12

    The Gemini Planet Imager is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of the Gemini Planet Imager has been tuned for maximum sensitivity to faint planets near bright stars. During first-light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-σ contrast of 106 at 0.75 arcseconds and 105 at 0.35 arcseconds. Observations of Beta Pictoris clearly detect the planet, Beta Pictoris b, in a singlemore » 60-s exposure with minimal postprocessing. Beta Pictoris b is observed at a separation of 434 ± 6 milliarcseconds (mas) and position angle 211.8 ± 0.5°. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of 3 improvement in most parameters over previous solutions. The planet orbits at a semimajor axis of 9.0+0.8–0.4 AU near the 3:2 resonance with the previously known 6-AU asteroidal belt and is aligned with the inner warped disk. In conclusion, the observations give a 4% probability of a transit of the planet in late 2017.« less

  16. First light of the Gemini Planet Imager

    PubMed Central

    Macintosh, Bruce; Graham, James R.; Ingraham, Patrick; Konopacky, Quinn; Marois, Christian; Perrin, Marshall; Poyneer, Lisa; Bauman, Brian; Barman, Travis; Burrows, Adam S.; Cardwell, Andrew; Chilcote, Jeffrey; De Rosa, Robert J.; Dillon, Daren; Doyon, Rene; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P.; Gavel, Donald; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Kalas, Paul; Larkin, James; Maire, Jerome; Marchis, Franck; Marley, Mark S.; McBride, James; Millar-Blanchaer, Max; Morzinski, Katie; Norton, Andrew; Oppenheimer, B. R.; Palmer, David; Patience, Jennifer; Pueyo, Laurent; Rantakyro, Fredrik; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Soummer, Remi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wiktorowicz, Sloane; Wolff, Schuyler

    2014-01-01

    The Gemini Planet Imager is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of the Gemini Planet Imager has been tuned for maximum sensitivity to faint planets near bright stars. During first-light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-σ contrast of 106 at 0.75 arcseconds and 105 at 0.35 arcseconds. Observations of Beta Pictoris clearly detect the planet, Beta Pictoris b, in a single 60-s exposure with minimal postprocessing. Beta Pictoris b is observed at a separation of 434 ± 6 milliarcseconds (mas) and position angle 211.8 ± 0.5°. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of 3 improvement in most parameters over previous solutions. The planet orbits at a semimajor axis of 9.0−0.4+0.8 AU near the 3:2 resonance with the previously known 6-AU asteroidal belt and is aligned with the inner warped disk. The observations give a 4% probability of a transit of the planet in late 2017. PMID:24821792

  17. Tumbling and spaceflight: the Gemini VIII experience.

    PubMed

    Mohler, S R; Nicogossian, A E; McCormack, P D; Mohler, S R

    1990-01-01

    A malfunctioning orbital flight attitude thruster during the flight of Gemini VIII led to acceleration forces on astronauts Neil Armstrong (commander) and David Scott (pilot) that created the potential for derogation of oculo-vestibular and eye-hand coordination effects. The spacecraft attained an axial tumbling rotation of 50 rpm and would have exceeded this had not the commander accurately diagnosed the problem and taken immediate corrective action. By the time counter-measure controls were applied, both astronauts were experiencing vertigo and the physiological effects of the tumbling acceleration. Data from the recorders reveal that one astronaut experienced -Gy of 0.92 G-units, and the other +Gy of 0.92 for approximately 46 s. Both received a -Gz of 0.89 G-units from the waist up with a +Gz of 0.05 from the waist down. A substantial increase of time and/or an increase in rpm would ultimately have produced incapacitation of both astronauts. NASA corrected the Gemini thruster problem by changing the ignition system wiring. Future space-craft undertaking long-term missions could be equipped with unambiguous thruster fault displays and could have computer-controlled automatic cutoffs to control excessive thruster burns. PMID:2302130

  18. First light of the Gemini Planet imager.

    PubMed

    Macintosh, Bruce; Graham, James R; Ingraham, Patrick; Konopacky, Quinn; Marois, Christian; Perrin, Marshall; Poyneer, Lisa; Bauman, Brian; Barman, Travis; Burrows, Adam S; Cardwell, Andrew; Chilcote, Jeffrey; De Rosa, Robert J; Dillon, Daren; Doyon, Rene; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P; Gavel, Donald; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Kalas, Paul; Larkin, James; Maire, Jerome; Marchis, Franck; Marley, Mark S; McBride, James; Millar-Blanchaer, Max; Morzinski, Katie; Norton, Andrew; Oppenheimer, B R; Palmer, David; Patience, Jennifer; Pueyo, Laurent; Rantakyro, Fredrik; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Soummer, Remi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J Kent; Wiktorowicz, Sloane; Wolff, Schuyler

    2014-09-01

    The Gemini Planet Imager is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of the Gemini Planet Imager has been tuned for maximum sensitivity to faint planets near bright stars. During first-light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-σ contrast of 10(6) at 0.75 arcseconds and 10(5) at 0.35 arcseconds. Observations of Beta Pictoris clearly detect the planet, Beta Pictoris b, in a single 60-s exposure with minimal postprocessing. Beta Pictoris b is observed at a separation of 434 ± 6 milliarcseconds (mas) and position angle 211.8 ± 0.5°. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of 3 improvement in most parameters over previous solutions. The planet orbits at a semimajor axis of [Formula: see text] near the 3:2 resonance with the previously known 6-AU asteroidal belt and is aligned with the inner warped disk. The observations give a 4% probability of a transit of the planet in late 2017. PMID:24821792

  19. First light of the Gemini Planet imager.

    PubMed

    Macintosh, Bruce; Graham, James R; Ingraham, Patrick; Konopacky, Quinn; Marois, Christian; Perrin, Marshall; Poyneer, Lisa; Bauman, Brian; Barman, Travis; Burrows, Adam S; Cardwell, Andrew; Chilcote, Jeffrey; De Rosa, Robert J; Dillon, Daren; Doyon, Rene; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P; Gavel, Donald; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Kalas, Paul; Larkin, James; Maire, Jerome; Marchis, Franck; Marley, Mark S; McBride, James; Millar-Blanchaer, Max; Morzinski, Katie; Norton, Andrew; Oppenheimer, B R; Palmer, David; Patience, Jennifer; Pueyo, Laurent; Rantakyro, Fredrik; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Soummer, Remi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J Kent; Wiktorowicz, Sloane; Wolff, Schuyler

    2014-09-01

    The Gemini Planet Imager is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of the Gemini Planet Imager has been tuned for maximum sensitivity to faint planets near bright stars. During first-light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-σ contrast of 10(6) at 0.75 arcseconds and 10(5) at 0.35 arcseconds. Observations of Beta Pictoris clearly detect the planet, Beta Pictoris b, in a single 60-s exposure with minimal postprocessing. Beta Pictoris b is observed at a separation of 434 ± 6 milliarcseconds (mas) and position angle 211.8 ± 0.5°. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of 3 improvement in most parameters over previous solutions. The planet orbits at a semimajor axis of [Formula: see text] near the 3:2 resonance with the previously known 6-AU asteroidal belt and is aligned with the inner warped disk. The observations give a 4% probability of a transit of the planet in late 2017.

  20. First light of the Gemini Planet Imager

    SciTech Connect

    Macintosh, Bruce; Graham, James R.; Ingraham, Patrick; Konopacky, Quinn; Marois, Christian; Perrin, Marshall; Poyneer, Lisa; Bauman, Brian; Barman, Travis; Burrows, Adam S.; Cardwell, Andrew; Chilcote, Jeffrey; De Rosa, Robert J.; Dillon, Daren; Doyon, Rene; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P.; Gavel, Donald; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Kalas, Paul; Larkin, James; Maire, Jerome; Marchis, Franck; Marley, Mark S.; McBride, James; Millar-Blanchaer, Max; Morzinski, Katie; Norton, Andrew; Oppenheimer, B. R.; Palmer, David; Patience, Jennifer; Pueyo, Laurent; Rantakyro, Fredrik; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Soummer, Remi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wiktorowicz, Stone; Wolff, Schuyler

    2014-05-12

    The Gemini Planet Imager is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of the Gemini Planet Imager has been tuned for maximum sensitivity to faint planets near bright stars. During first-light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-σ contrast of 106 at 0.75 arcseconds and 105 at 0.35 arcseconds. Observations of Beta Pictoris clearly detect the planet, Beta Pictoris b, in a single 60-s exposure with minimal postprocessing. Beta Pictoris b is observed at a separation of 434 ± 6 milliarcseconds (mas) and position angle 211.8 ± 0.5°. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of 3 improvement in most parameters over previous solutions. The planet orbits at a semimajor axis of 9.0+0.8–0.4 AU near the 3:2 resonance with the previously known 6-AU asteroidal belt and is aligned with the inner warped disk. In conclusion, the observations give a 4% probability of a transit of the planet in late 2017.

  1. Tumbling and spaceflight: the Gemini VIII experience.

    PubMed

    Mohler, S R; Nicogossian, A E; McCormack, P D; Mohler, S R

    1990-01-01

    A malfunctioning orbital flight attitude thruster during the flight of Gemini VIII led to acceleration forces on astronauts Neil Armstrong (commander) and David Scott (pilot) that created the potential for derogation of oculo-vestibular and eye-hand coordination effects. The spacecraft attained an axial tumbling rotation of 50 rpm and would have exceeded this had not the commander accurately diagnosed the problem and taken immediate corrective action. By the time counter-measure controls were applied, both astronauts were experiencing vertigo and the physiological effects of the tumbling acceleration. Data from the recorders reveal that one astronaut experienced -Gy of 0.92 G-units, and the other +Gy of 0.92 for approximately 46 s. Both received a -Gz of 0.89 G-units from the waist up with a +Gz of 0.05 from the waist down. A substantial increase of time and/or an increase in rpm would ultimately have produced incapacitation of both astronauts. NASA corrected the Gemini thruster problem by changing the ignition system wiring. Future space-craft undertaking long-term missions could be equipped with unambiguous thruster fault displays and could have computer-controlled automatic cutoffs to control excessive thruster burns.

  2. DYNAMICAL MASS OF THE M8+M8 BINARY 2MASS J22062280 - 2047058AB {sup ,} {sup ,} {sup ,}

    SciTech Connect

    Dupuy, Trent J.; Bowler, Brendan P.; Liu, Michael C.

    2009-11-20

    We present Keck laser guide star adaptive optics imaging of the M8+M8 binary 2MASS J2206 - 2047AB. Together with archival Hubble Space Telescope, Gemini-North, and Very Large Telescope data, our observations span 8.3 yr of the binary's 35{sup +6}{sub -5} yr orbital period, and we determine a total dynamical mass of 0.15{sup +0.05} {sub -0.03} M{sub sun}, with the uncertainty dominated by the parallax error. Using the measured total mass and individual luminosities, the Tucson and Lyon evolutionary models both give an age for the system of 0.4{sup +9.6}{sub -0.2} Gyr, which is consistent with its thin disk space motion derived from the Besancon Galactic structure model. Our mass measurement combined with the Tucson (Lyon) evolutionary models also yields precise effective temperatures, giving 2660{sup +90}{sub -100} K and 2640{sup +90}{sub -100} K (2550{sup +90}{sub -100} K and 2530{sup +90}{sub -100} K) for components A and B, respectively. These temperatures are in good agreement with estimates for other M8 dwarfs (from the infrared flux method and the M8 mass benchmark LHS 2397aA), but atmospheric model fitting of the integrated-light spectrum gives hotter temperatures of 2800 +- 100 K for both components. This modest discrepancy can be explained by systematic errors in the atmospheric models or by a slight underestimation of the distance (and thus, mass and age) of the system. We also find that the observed near-infrared colors and magnitudes do not agree with those predicted by the Lyon Dusty models, given the known mass of the system.

  3. Active compensation of flexure on the High-Resolution Optical Spectrograph for Gemini

    NASA Astrophysics Data System (ADS)

    D'Arrigo, P.; Diego, Francisco; Walker, David D.

    1997-03-01

    Gravity-induced flexure has been a long-standing challenge in Cassegrain spectrographs at 4-meter class telescopes; it is the more so at the scale of 8-meter telescopes. This is of particular concern for the Gemini high resolution optical spectrograph, which will be Cassegrain-mounted for its routine mode of operation. In this paper we address the general flexure problem, and how to solve it with the use of active optics. We also present the results of an experimental active flexure compensation system for the ISIS (intermediate- dispersion spectroscopic and imaging system) spectrograph on the 4.2 m William Herschel Telescope (WHT). This instrument, called ISAAC (ISIS spectrograph automatic active collimator), is based on the concept of active correction, where spectrum drifts, due to the spectrograph flexing under the effect of gravity, are compensated by the movement of an active optical element (in this case a fine steering tip-tilt collimator mirror). The experiment showed that active compensation can reduce flexure down to less than 3 micrometer over four hours of telescope motions, dramatically improving the spectrograph performance. The results of the experiment are used to discuss a flexure compensation system for the high resolution optical spectrograph (HROS) for the 8 m Gemini telescope.

  4. Results from the Gemini NICI Planet-Finding Campaign

    NASA Astrophysics Data System (ADS)

    Biller, Beth A.; Liu, Michael C.; Wahhaj, Zahed; Nielsen, Eric L.; Hayward, Thomas L.; Chun, Mark R.; Close, Laird M.; Ftaclas, Christ; Males, Jared R.; Hartung, Markus; Reid, I. N.; Shkolnik, Evgenya; Skemer, Andrew J.; Tecza, Matthias; Thatte, Niranjan A.; Clarke, Fraser; Toomey, Douglas

    2014-08-01

    From 2008 December to 2012 September, the NICI (Near-Infrared Coronagraphic Imager at the Gemini-South 8.1-m) Planet-Finding Campaign (Liu et al. 2010) obtained deep, high-contrast AO imaging of a carefully selected sample of over 200 young, nearby stars. In the course of the campaign, we discovered four co-moving brown dwarf companions: PZ Tel B (36+/-6 MJup, 16.4+/-1.0 AU), CD-35 2722B (31+/-8 MJup, 67+/-4 AU), HD 1160B (33+12 -9 MJup, 81+/- AU), and HIP 79797Bb (55+20-19MJup, 3 AU from the previously known brown dwarf companion HIP 79797Ba), as well as numerous stellar binaries. Three survey papers have been published to date, covering: 1) high mass stars (Nielsen et al. 2013), 2) debris disk stars (Wahhaj et al. 2013), and 3) stars which are members of nearby young moving groups (Biller et al. 2013). In addition, the Campaign has yielded new orbital constraints for the ~8-10 MJup planet Pic β (Nielsen et al. 2014) and a high precision measurement of the star-disk offset for the well-known disk around HR 4796A (Wahhaj et al. 2014). Here we discuss constraints placed on the distribution of wide giant exoplanets from the NICI Campaign, new substellar companion discoveries, and characterization both of exoplanets and circumstellar disks.

  5. Geo-Engineering through Internet Informatics (GEMINI)

    SciTech Connect

    Watney, W. Lynn; Doveton, John H.; Victorine, John R.; Bohling, Goeffrey C.; Bhattacharya, Saibal; Byers, Alan P.; Carr, Timothy R.; Dubois, Martin K.; Gagnon, Glen; Guy, Willard J.; Look, Kurt; Magnuson, Mike; Moore, Melissa; Olea, Ricardo; Pakalapadi, Jayprakash; Stalder, Ken; Collins, David R.

    2002-06-25

    GEMINI will resolve reservoir parameters that control well performance; characterize subtle reservoir properties important in understanding and modeling hydrocarbon pore volume and fluid flow; expedite recognition of bypassed, subtle, and complex oil and gas reservoirs at regional and local scale; differentiate commingled reservoirs; build integrated geologic and engineering model based on real-time, iterate solutions to evaluate reservoir management options for improved recovery; provide practical tools to assist the geoscientist, engineer, and petroleum operator in making their tasks more efficient and effective; enable evaluations to be made at different scales, ranging from individual well, through lease, field, to play and region (scalable information infrastructure); and provide training and technology transfer to evaluate capabilities of the client.

  6. The Gemini Planet Imager: integration and status

    NASA Astrophysics Data System (ADS)

    Macintosh, Bruce A.; Anthony, Andre; Atwood, Jennifer; Barriga, Nicolas; Bauman, Brian; Caputa, Kris; Chilcote, Jeffery; Dillon, Daren; Doyon, René; Dunn, Jennifer; Gavel, Donald T.; Galvez, Ramon; Goodsell, Stephen J.; Graham, James R.; Hartung, Markus; Isaacs, Joshua; Kerley, Dan; Konopacky, Quinn; Labrie, Kathleen; Larkin, James E.; Maire, Jerome; Marois, Christian; Millar-Blanchaer, Max; Nunez, Arturo; Oppenheimer, Ben R.; Palmer, David W.; Pazder, John; Perrin, Marshall; Poyneer, Lisa A.; Quirez, Carlos; Rantakyro, Frederik; Reshtov, Vlad; Saddlemyer, Leslie; Sadakuni, Naru; Savransky, Dmitry; Sivaramakrishnan, Anand; Smith, Malcolm; Soummer, Remi; Thomas, Sandrine; Wallace, J. Kent; Weiss, Jason; Wiktorowicz, Sloane

    2012-09-01

    The Gemini Planet Imager is a next-generation instrument for the direct detection and characterization of young warm exoplanets, designed to be an order of magnitude more sensitive than existing facilities. It combines a 1700-actuator adaptive optics system, an apodized-pupil Lyot coronagraph, a precision interferometric infrared wavefront sensor, and a integral field spectrograph. All hardware and software subsystems are now complete and undergoing integration and test at UC Santa Cruz. We will present test results on each subsystem and the results of end-to-end testing. In laboratory testing, GPI has achieved a raw contrast (without post-processing) of 10-6 5σ at 0.4", and with multiwavelength speckle suppression, 2x10-7 at the same separation.

  7. Gemini: A long-range cargo transport

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The proposed Gemini, a long-range cargo transport, is designed as a high capacity, dedicated cargo transporter of 8'x8'x20' inter-modal containers, and long-range design. These requirements will result in a design that is larger than any existing aircraft. Due to the size, a conventional configuration would result in an aircraft unable to operate economically at existing airports. It is necessary to design for a minimum possible empty weight, wingspan, and landing gear track. After considering both a single fuselage biplane and a double fuselage biplane configuration, the design team choose the double fuselage biplane configuration. Both of these configuration choices result in a reduced wing root bending moment and subsequently in substantial savings in the wing weight. An overall decrease in the weight of the airplane, its systems, and fuel will be a direct result of the wing weight savings.

  8. Wavefront control for the Gemini Planet Imager

    SciTech Connect

    Poyneer, L A; Veran, J; Dillon, D; Severson, S; Macintosh, B

    2006-04-14

    The wavefront control strategy for the proposed Gemini Planet Imager, an extreme adaptive optics coronagraph for planet detection, is presented. Two key parts of this strategy are experimentally verified in a testbed at the Laboratory for Adaptive Optics, which features a 32 x 32 MEMS device. Detailed analytic models and algorithms for Shack-Hartmann wavefront sensor alignment and calibration are presented. It is demonstrated that with these procedures, the spatially filtered WFS and the Fourier Transform reconstructor can be used to flatten to the MEMS to 1 nm RMS in the controllable band. Performance is further improved using the technique of modifying the reference slopes using a measurement of the static wavefront error in the science leg.

  9. The Gemini Planet Imager Exoplanet Survey

    NASA Astrophysics Data System (ADS)

    Macintosh, Bruce

    The Gemini Planet Imager (GPI) is a next-generation coronagraph constructed for the Gemini Observatory. GPI will see first light this fall. It will be the most advanced planet-imaging system in operation - an order of magnitude more sensitive than any current instrument, capable of detecting and spectroscopically characterizing young Jovian planets 107 times fainter than their parent star at separations of 0.2 arcseconds. GPI was built from the beginning as a facility-class survey instrument, and the observatory will employ it that way. Our team has been selected by Gemini Observatory to carry out an 890-hour program - the GPI Exoplanet Survey (GPIES) campaign from 2014-2017. We will observe 600 stars spanning spectral types A-M. We will use published young association catalogs and a proprietary list in preparation that adds several hundred new young (<100 Myr, <75 pc) and adolescent (<300 Myr, <35 pc) stars. The range of separations studied by GPI is completely inaccessible to Doppler and transit techniques (even with Kepler or TESS)— GPI offers a new window into planet formation. We will use GPI to produce the first-ever robust census of giant planet populations in the 5-50 AU range, allowing us to: 1) illuminate the formation pathways of Jovian planets; 2) reconstruct the early dynamical evolution of systems, including migration mechanisms and the interaction with disks and belts of debris; and 3) bridge the gap between Jupiter and the brown dwarfs with the first examples of cool low- gravity planetary atmospheres. Simulations predict this survey will discover approximately 50 exoplanets, increasing the number of exoplanet images by an order of magnitude, enough for statistical investigation. This Origins of Solar Systems proposal will support the execution of the GPI Exoplanet Survey campaign. We will develop tools needed to execute the survey efficiently. We will refine the existing GPI data pipeline to a final version that robustly removes residual speckle

  10. First light of the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Macintosh, Bruce; Graham, James R.; Ingraham, Patrick; Konopacky, Quinn; Marois, Christian; Perrin, Marshall; Poyneer, Lisa; Bauman, Brian; Barman, Travis; Burrows, Adam S.; Cardwell, Andrew; Chilcote, Jeffrey; De Rosa, Robert J.; Dillon, Daren; Doyon, Rene; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P.; Gavel, Donald; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Kalas, Paul; Larkin, James; Maire, Jerome; Marchis, Franck; Marley, Mark S.; McBride, James; Millar-Blanchaer, Max; Morzinski, Katie; Norton, Andrew; Oppenheimer, B. R.; Palmer, David; Patience, Jennifer; Pueyo, Laurent; Rantakyro, Fredrik; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Soummer, Remi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wiktorowicz, Sloane; Wolff, Schuyler

    2014-09-01

    The Gemini Planet Imager is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of the Gemini Planet Imager has been tuned for maximum sensitivity to faint planets near bright stars. During first-light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-σ contrast of 106 at 0.75 arcseconds and 105 at 0.35 arcseconds. Observations of Beta Pictoris clearly detect the planet, Beta Pictoris b, in a single 60-s exposure with minimal postprocessing. Beta Pictoris b is observed at a separation of 434 ± 6 milliarcseconds (mas) and position angle 211.8 ± 0.5°. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of 3 improvement in most parameters over previous solutions. The planet orbits at a semimajor axis of 9.0-0.4+0.8AU near the 3:2 resonance with the previously known 6-AU asteroidal belt and is aligned with the inner warped disk. The observations give a 4% probability of a transit of the planet in late 2017.

  11. Structural Characterization of Novel Gemini Non-viral DNA

    SciTech Connect

    Foldvari,M.; Badea, I.; Wettig, S.; Verrall, R.; Bagonluri, M.

    2006-01-01

    The structural and physicochemical properties of novel cationic lipid-based DNA complexes have been investigated for the purpose of designing micro/nano-scale self-assembling delivery systems for cutaneous gene therapy. DNA/gemini surfactant (spacer n = 3-16; chain m = 12 or 16) complexes (1 : 10 charge ratio), with or without dioleoylphosphatidyl-ethanolamine (DOPE), designed for cellular transfection, were generally in the range of 100-200 nm as demonstrated by atomic force microscopy and particle size analysis. Small-angle X-ray scattering measurements indicated that the DNA/gemini complexes lacked long-range order, whereas DNA/gemini/DOPE complexes exhibited lamellar and polymorphic phases other than hexagonal. Correlation studies using transfection efficiency data in PAM 212 keratinocytes and in vitro skin absorption indicated that formulations containing gemini surfactants having the ability to induce structures other than lamellar in the resulting complexes, generally exhibited greater transfection activity and cutaneous absorption.

  12. Food packages for use on the Gemini 4 flight

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Food packages for use on the Gemini 4 flight. Packages include beef and gravy, peaches, strawberry cereal cubes and beef sandwiches. Water gun is used to reconstitute dehydrated food. Scissors are used to open the packages.

  13. Indonesian Islands as seen from Gemini 11 spacecraft

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Indonesian Islands (partial cloud cover): Sumatra, Java, Bali, Borneo, Sumbawa, as photographed from the Gemini 11 spacecraft during its 26th revolution of the earth, at an altitude of 570 nautical miles.

  14. View of Gemini 11 experiment S-13 Ultraviolet Astronomical Camera

    NASA Technical Reports Server (NTRS)

    1966-01-01

    View of Gemini 11 experiment S-13 Ultraviolet Astronomical Camera before flight. Its object was to obtain data on ultraviolet radiation of hot stars and to develop and evaluate basic techniques for photography of celestial objects from manned spacecraft.

  15. New serine-derived gemini surfactants as gene delivery systems.

    PubMed

    Cardoso, Ana M; Morais, Catarina M; Cruz, A Rita; Silva, Sandra G; do Vale, M Luísa; Marques, Eduardo F; de Lima, Maria C Pedroso; Jurado, Amália S

    2015-01-01

    Gemini surfactants have been extensively used for in vitro gene delivery. Amino acid-derived gemini surfactants combine the special aggregation properties characteristic of the gemini surfactants with high biocompatibility and biodegradability. In this work, novel serine-derived gemini surfactants, differing in alkyl chain lengths and in the linker group bridging the spacer to the headgroups (amine, amide and ester), were evaluated for their ability to mediate gene delivery either per se or in combination with helper lipids. Gemini surfactant-based DNA complexes were characterized in terms of hydrodynamic diameter, surface charge, stability in aqueous buffer and ability to protect DNA. Efficient formulations, able to transfect up to 50% of the cells without causing toxicity, were found at very low surfactant/DNA charge ratios (1/1-2/1). The most efficient complexes presented sizes suitable for intravenous administration and negative surface charge, a feature known to preclude potentially adverse interactions with serum components. This work brings forward a new family of gemini surfactants with great potential as gene delivery systems.

  16. GEMINI: Integrative Exploration of Genetic Variation and Genome Annotations

    PubMed Central

    Paila, Umadevi; Chapman, Brad A.; Kirchner, Rory; Quinlan, Aaron R.

    2013-01-01

    Modern DNA sequencing technologies enable geneticists to rapidly identify genetic variation among many human genomes. However, isolating the minority of variants underlying disease remains an important, yet formidable challenge for medical genetics. We have developed GEMINI (GEnome MINIng), a flexible software package for exploring all forms of human genetic variation. Unlike existing tools, GEMINI integrates genetic variation with a diverse and adaptable set of genome annotations (e.g., dbSNP, ENCODE, UCSC, ClinVar, KEGG) into a unified database to facilitate interpretation and data exploration. Whereas other methods provide an inflexible set of variant filters or prioritization methods, GEMINI allows researchers to compose complex queries based on sample genotypes, inheritance patterns, and both pre-installed and custom genome annotations. GEMINI also provides methods for ad hoc queries and data exploration, a simple programming interface for custom analyses that leverage the underlying database, and both command line and graphical tools for common analyses. We demonstrate GEMINI's utility for exploring variation in personal genomes and family based genetic studies, and illustrate its ability to scale to studies involving thousands of human samples. GEMINI is designed for reproducibility and flexibility and our goal is to provide researchers with a standard framework for medical genomics. PMID:23874191

  17. The Gemini Deep Planet Survey - GDPS

    SciTech Connect

    Lafreniere, D; Doyon, R; Marois, C; Nadeau, D; Oppenheimer, B R; Roche, P F; Rigaut, F; Graham, J R; Jayawardhana, R; Johnstone, D; Kalas, P G; Macintosh, B; Racine, R

    2007-06-01

    We present the results of the Gemini Deep Planet Survey, a near-infrared adaptive optics search for giant planets and brown dwarfs around nearby young stars. The observations were obtained with the Altair adaptive optics system at the Gemini North telescope and angular differential imaging was used to suppress the speckle noise of the central star. Detection limits for the 85 stars observed are presented, along with a list of all faint point sources detected around them. Typically, the observations are sensitive to angular separations beyond 0.5-inch with 5{sigma} contrast sensitivities in magnitude difference at 1.6 {micro}m of 9.6 at 0.5-inch, 12.9 at 1-inch, 15 at 2-inch, and 16.6 at 5-inch. For the typical target of the survey, a 100 Myr old K0 star located 22 pc from the Sun, the observations are sensitive enough to detect planets more massive than 2 M{sub Jup} with a projected separation in the range 40-200 AU. Depending on the age, spectral type, and distance of the target stars, the minimum mass that could be detected with our observations can be {approx}1 M{sub Jup}. Second epoch observations of 48 stars with candidates (out of 54) have confirmed that all candidates are unrelated background stars. A detailed statistical analysis of the survey results, which provide upper limits on the fractions of stars with giant planet or low mass brown dwarf companions, is presented. Assuming a planet mass distribution dn/dm {proportional_to} m{sup -1.2} and a semi-major axis distribution dn/da {proportional_to} a{sup -1}, the upper limits on the fraction of stars with at least one planet of mass 0.5-13 M{sub Jup} are 0.29 for the range 10-25 AU, 0.13 for 25-50 AU, and 0.09 for 50-250 AU, with a 95% confidence level; this result is weakly dependent on the semi-major axis distribution power-law index. Without making any assumption on the mass and semi-major axis distributions, the fraction of stars with at least one brown dwarf companion having a semi-major axis in the

  18. Gemini spectroscopy of the outer disk star cluster BH176

    NASA Astrophysics Data System (ADS)

    Sharina, M. E.; Donzelli, C. J.; Davoust, E.; Shimansky, V. V.; Charbonnel, C.

    2014-10-01

    Context. BH176 is an old metal-rich star cluster. It is spatially and kinematically consistent with belonging to the Monoceros Ring. It is larger in size and more distant from the Galactic plane than typical open clusters, and it does not belong to the Galactic bulge. Aims: Our aim is to determine the origin of this unique object by accurately determining its distance, metallicity, and age. The best way to reach this goal is to combine spectroscopic and photometric methods. Methods: We present medium-resolution observations of red clump and red giant branch stars in BH176 obtained with the Gemini South Multi-Object Spectrograph. We derive radial velocities, metallicities, effective temperatures, and surface gravities of the observed stars and use these parameters to distinguish member stars from field objects. Results: We determine the following parameters for BH176: Vh = 0 ± 15 km s-1, [Fe/H] = -0.1 ± 0.1, age 7 ± 0.5 Gyr, E(V - I) = 0.79 ± 0.03, distance 15.2 ± 0.2 kpc, α-element abundance [α/Fe] ~ 0.25 dex (the mean of [Mg/Fe], and [Ca/Fe]). Conclusions: BH176 is a member of old Galactic open clusters that presumably belong to the thick disk. It may have originated as a massive star cluster after the encounter of the forming thin disk with a high-velocity gas cloud or as a satellite dwarf galaxy. Appendix A is available in electronic form at http://www.aanda.org

  19. Experience with a new approach for instrument software at Gemini

    NASA Astrophysics Data System (ADS)

    Núñez, Arturo; Walker, Shane; Goodsell, Stephen; Dunn, Jennifer; Gillies, Kim

    2010-07-01

    Gemini Observatory is using a new approach with instrument software that takes advantage of the strengths of our instrument builders and at the same time better supports our own operational needs. A lightweight software library in conjunction with modern agile software development methodologies is being used to ameliorate the problems encountered with the development of the first and second-generation Gemini instruments. Over the last two years, Gemini and the team constructing the software for the Gemini Planet Imager (GPI) have been using an agile development process to implement the Gemini Instrument Application Interface (GIAPI) and the highlevel control software for the GPI instrument. The GPI is being tested and exercised with the GIAPI, and this has allowed us to perform early end-to-end testing of the instrument software. Early in 2009 for the first time in our development history, we were able to move instrument mechanisms with Gemini software during early instrument construction. As a result of this approach, we discovered and fixed software interface issues between Gemini and GPI. Resolving these problems at this stage is simpler and less expensive than when the full instrument is completed. GPI is currently approaching its integration and testing phase, which will occur in 2010. We expect that utilizing this new approach will yield a more robust software implementation resulting in smoother instrument integration, testing, and commissioning phases. In this paper we describe the key points of our approach and results of applying the new instrument API approach together with agile development methodologies. The paper concludes with lessons learned and suggestions for adapting agile approaches in other astronomy development projects.

  20. GEO-ENGINEERING MODELING THROUGH INTERNET INFORMATICS (GEMINI)

    SciTech Connect

    W. Lynn Watney; John H. Doveton

    2004-05-13

    GEMINI (Geo-Engineering Modeling through Internet Informatics) is a public-domain web application focused on analysis and modeling of petroleum reservoirs and plays (http://www.kgs.ukans.edu/Gemini/index.html). GEMINI creates a virtual project by ''on-the-fly'' assembly and analysis of on-line data either from the Kansas Geological Survey or uploaded from the user. GEMINI's suite of geological and engineering web applications for reservoir analysis include: (1) petrofacies-based core and log modeling using an interactive relational rock catalog and log analysis modules; (2) a well profile module; (3) interactive cross sections to display ''marked'' wireline logs; (4) deterministic gridding and mapping of petrophysical data; (5) calculation and mapping of layer volumetrics; (6) material balance calculations; (7) PVT calculator; (8) DST analyst, (9) automated hydrocarbon association navigator (KHAN) for database mining, and (10) tutorial and help functions. The Kansas Hydrocarbon Association Navigator (KHAN) utilizes petrophysical databases to estimate hydrocarbon pay or other constituent at a play- or field-scale. Databases analyzed and displayed include digital logs, core analysis and photos, DST, and production data. GEMINI accommodates distant collaborations using secure password protection and authorized access. Assembled data, analyses, charts, and maps can readily be moved to other applications. GEMINI's target audience includes small independents and consultants seeking to find, quantitatively characterize, and develop subtle and bypassed pays by leveraging the growing base of digital data resources. Participating companies involved in the testing and evaluation of GEMINI included Anadarko, BP, Conoco-Phillips, Lario, Mull, Murfin, and Pioneer Resources.

  1. Gemini-IFU spectroscopy of HH 111

    SciTech Connect

    Cerqueira, A. H.; Vasconcelos, M. J.; Feitosa, J.; Plana, H.; Raga, A. C.

    2015-03-01

    We present new optical observations of the Herbig–Haro (HH) 111 jet using the Gemini Multi Object Spectrograph in its Integral Field Unit mode. Eight fields of 5{sup ′′}×3.{sup ′′}5 have been positioned along and across the HH 111 jet, covering the spatial region from knot E to L in HH 111 (namely, knots E, F, G, H, J, K, and L). We present images and velocity channel maps for the [O i] 6300+6360, Hα, [N ii] 6548+6583, and [S ii] 6716+6730 lines, as well as for the [S ii] 6716/6730 line ratio. We find that the HH 111 jet has an inner region with lower excitation and higher radial velocity, surrounded by a broader region of higher excitation and lower radial velocity. Also, we find higher electron densities at lower radial velocities. These results imply that the HH 111 jet has a fast, axial region with lower velocity shocks surrounded by a lower velocity sheath with higher velocity shocks.

  2. Gemini, a Bifunctional Enzymatic and Fluorescent Reporter of Gene Expression

    PubMed Central

    Endy, Drew

    2009-01-01

    Background The development of collections of quantitatively characterized standard biological parts should facilitate the engineering of increasingly complex and novel biological systems. The existing enzymatic and fluorescent reporters that are used to characterize biological part functions exhibit strengths and limitations. Combining both enzymatic and fluorescence activities within a single reporter protein would provide a useful tool for biological part characterization. Methodology/Principal Findings Here, we describe the construction and quantitative characterization of Gemini, a fusion between the β-galactosidase (β-gal) α-fragment and the N-terminus of full-length green fluorescent protein (GFP). We show that Gemini exhibits functional β-gal activity, which we assay with plates and fluorometry, and functional GFP activity, which we assay with fluorometry and microscopy. We show that the protein fusion increases the sensitivity of β-gal activity and decreases the sensitivity of GFP. Conclusions/Significance Gemini is therefore a bifunctional reporter with a wider dynamic range than the β-gal α-fragment or GFP alone. Gemini enables the characterization of gene expression, screening assays via enzymatic activity, and quantitative single-cell microscopy or FACS via fluorescence activity. The analytical flexibility afforded by Gemini will likely increase the efficiency of research, particularly for screening and characterization of libraries of standard biological parts. PMID:19888458

  3. Sky Background Variability Measured on Maunakea at Gemini North Observatory

    NASA Astrophysics Data System (ADS)

    Smith, Adam B.; Roth, Katherine; Stephens, Andrew W.

    2016-01-01

    Gemini North has recently implemented a Quality Assessment Pipeline (QAP) that automatically reduces images in realtime to determine sky condition quantities, including background sky brightness from the optical to near-infrared. Processing archived images through the QAP and mining the results allows us to look for trends and systematic issues with the instruments and optics during the first decade of Gemini.Here we present the results of using the QAP calculated values to quantify how airglow affects the background sky brightness of images taken with Gemini's imaging instruments, GMOS and NIRI, as well as searching for other factors that may cause changes in the sky brightness. By investigating the dependence of measured sky brightness as a function of a variety of variables, including time after twilight, airmass, season, distance from the moon, air temperature, etc., we quantify the effect of sky brightness and its impact on the sensitivity of Gemini optical and near-infrared imaging data. These measurements will be used to determine new sky background relationships for Maunakea, and to improve the Gemini Integration Time Calculators (ITCs).

  4. Close-up view of Gemini 9 spacecraft taken during EVA

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Astronaut Eugene A. Cernan took this close-up view of the Gemini 9 spacecraft during his extravehicular activity on the Gemini 9 mission. Taken during the 32nd revolution of the 72 hr. 21 min. space flight.

  5. Astronaut Virgil Grissom shown through window of open hatch on Gemini craft

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Astronaut Virgil I. Grissom, the command pilot of the Gemini-Titan 3 three orbit mission, is shown through the window of the open hatch on Gemini spacecraft in the white room on the mornining of the launch.

  6. GEMINI/GeMS Observations Unveil the Structure of the Heavily Obscured Globular Cluster Liller 1.

    NASA Astrophysics Data System (ADS)

    Saracino, S.; Dalessandro, E.; Ferraro, F. R.; Lanzoni, B.; Geisler, D.; Mauro, F.; Villanova, S.; Moni Bidin, C.; Miocchi, P.; Massari, D.

    2015-06-01

    By exploiting the exceptional high-resolution capabilities of the near-IR camera GSAOI combined with the Gemini Multi-Conjugate Adaptive System at the GEMINI South Telescope, we investigated the structural and physical properties of the heavily obscured globular cluster Liller 1 in the Galactic bulge. We have obtained the deepest and most accurate color–magnitude diagram published so far for this cluster, reaching {{K}s}∼ 19 (below the main-sequence turnoff level). We used these data to redetermine the center of gravity of the system, finding that it is located about 2.″2 southeast from the literature value. We also built new star density and surface brightness profiles for the cluster and rederived its main structural and physical parameters (scale radii, concentration parameter, central mass density, total mass). We find that Liller 1 is significantly less concentrated (concentration parameter c=1.74) and less extended (tidal radius {{r}t}=298\\prime\\prime and core radius {{r}c}=5\\buildrel{\\prime\\prime}\\over{.} 39) than previously thought. By using these newly determined structural parameters, we estimated the mass of Liller 1 to be {{M}tot}=2.3+0.3-0.1× {{10}6} {{M}ȯ } ({{M}tot}=1.5+0.2-0.1× {{10}6} {{M}ȯ } for a Kroupa initial mass function), which is comparable to that of the most massive clusters in the Galaxy (ω Centari and Terzan 5). Also, Liller 1 has the second-highest collision rate (after Terzan 5) among all star clusters in the Galaxy, thus confirming that it is an ideal environment for the formation of collisional objects (such as millisecond pulsars). Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da

  7. GEMINI/GeMS Observations Unveil the Structure of the Heavily Obscured Globular Cluster Liller 1.

    NASA Astrophysics Data System (ADS)

    Saracino, S.; Dalessandro, E.; Ferraro, F. R.; Lanzoni, B.; Geisler, D.; Mauro, F.; Villanova, S.; Moni Bidin, C.; Miocchi, P.; Massari, D.

    2015-06-01

    By exploiting the exceptional high-resolution capabilities of the near-IR camera GSAOI combined with the Gemini Multi-Conjugate Adaptive System at the GEMINI South Telescope, we investigated the structural and physical properties of the heavily obscured globular cluster Liller 1 in the Galactic bulge. We have obtained the deepest and most accurate color-magnitude diagram published so far for this cluster, reaching {{K}s}˜ 19 (below the main-sequence turnoff level). We used these data to redetermine the center of gravity of the system, finding that it is located about 2.″2 southeast from the literature value. We also built new star density and surface brightness profiles for the cluster and rederived its main structural and physical parameters (scale radii, concentration parameter, central mass density, total mass). We find that Liller 1 is significantly less concentrated (concentration parameter c=1.74) and less extended (tidal radius {{r}t}=298\\prime\\prime and core radius {{r}c}=5\\buildrel{\\prime\\prime}\\over{.} 39) than previously thought. By using these newly determined structural parameters, we estimated the mass of Liller 1 to be {{M}tot}=2.3+0.3-0.1× {{10}6} {{M}⊙ } ({{M}tot}=1.5+0.2-0.1× {{10}6} {{M}⊙ } for a Kroupa initial mass function), which is comparable to that of the most massive clusters in the Galaxy (ω Centari and Terzan 5). Also, Liller 1 has the second-highest collision rate (after Terzan 5) among all star clusters in the Galaxy, thus confirming that it is an ideal environment for the formation of collisional objects (such as millisecond pulsars). Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da

  8. Gemini/GMOS imaging of globular cluster systems in five early-type galaxies

    NASA Astrophysics Data System (ADS)

    Faifer, Favio R.; Forte, Juan C.; Norris, Mark A.; Bridges, Terry; Forbes, Duncan A.; Zepf, Stephen E.; Beasley, Mike; Gebhardt, Karl; Hanes, David A.; Sharples, Ray M.

    2011-09-01

    In this paper, we present deep high-quality photometry of globular cluster systems (GCSs) belonging to five early-type galaxies, covering a range of mass and environment. Photometric data were obtained with the Gemini North and Gemini South telescopes in the filter passbands g', r' and i'. The combination of these filters with good seeing conditions allows an excellent separation between globular cluster (GC) candidates and unresolved field objects. In fact, our previously published spectroscopic data indicate a contamination level of only ˜10 per cent in our sample of GC candidates. Bimodal GC colour distributions are found in all five galaxies. Most of the GCSs appear bimodal even in the (g'-r') versus (r'-i') plane. A population of resolved/marginally resolved GC and ultracompact dwarf candidates was found in all the galaxies. A search for the so-called 'blue tilt' in the colour-magnitude diagrams reveals that NGC 4649 clearly shows this phenomenon, although no conclusive evidence was found for the other galaxies in the sample. This 'blue tilt' translates into a mass-metallicity relation given by Z∝M0.28 ±0.03. This dependence was found using a new empirical (g'-i') versus [Z/H] relation, which relies on an homogeneous sample of GC colours and metallicities. In this paper, we also explore the radial trends in both colour and surface density for the blue (metal-poor) and red (metal-rich) GC subpopulations. As usual, the red GCs show a steeper radial distribution than the blue GCs. Evidence of galactocentric colour gradients is found in some of the GCSs, which is more significant for the two S0 galaxies in the sample. Red GC subpopulations show similar colours and gradients to the galaxy halo stars in their inner region. A GC mean colour-galaxy luminosity relation, consistent with [Z/H]∝L0.26 ±0.08B, is present for the red GCs. Estimates of the total GC populations and specific frequency SN values are presented for NGC 3115, 3923 and 4649. Based on

  9. Gemini J-band observations of RX J0806.4-4123

    NASA Astrophysics Data System (ADS)

    Posselt, B.; Luhman, K. L.

    2016-07-01

    The detection of near-infrared (NIR) excess at the position of a star can indicate either a substellar companion or a disk around the respective star. In this work we probed whether a 2.5σ H-band flux enhancement at the position of the isolated neutron star RX J0806.4-4123 can be confirmed at another NIR wavelength. We observed RX J0806.4-4123 in the J-band with Gemini South equipped with FLAMINGOS-2. There was no significant detection of a J-band source at the neutron star position. However, similarly to the H-band we found a very faint (1.4σ) flux enhancement with a nominal magnitude of J=24.8 ± 0.5. The overall NIR-detection significance is 3.1σ. If real, this emission is too bright to come from the neutron star alone. Deeper near-infrared observations are necessary to confirm or refute the potential NIR excess. The confirmation of such NIR excess could imply that there is a substellar companion or a disk around RX J0806.4-4123. Based on observations obtained at the Gemini Observatory (Program ID: GS-2014B-Q-60) and ESO Paranal Observatory (Program ID: 74.C-0596)

  10. The system support associate model at Gemini Observatory

    NASA Astrophysics Data System (ADS)

    Hainaut, Marie-Claire; Coulson, Dolores

    2008-07-01

    At Gemini Observatory, the traditional employment position of telescope operator has been discarded in favor of a more diverse and flexible position known as System Support Associate (SSA). From the very beginning, the operational model of Gemini was designed to involve SSAs in observatory projects well beyond the strict operation of the telescope systems. We describe the motivation behind the original model, how it was eventually implemented and how it has evolved. We describe how the schedule allows SSAs to assume different roles within Gemini and how flexible time allows them to participate to a wide range of projects, increasing their motivation, deepening their knowledge and strengthening communication between groups, as well as allowing management to allocate resources to projects that would otherwise lack manpower. We give examples of such projects and comment on the difficulties inherent in the model.

  11. Thermal emissivity analysis of a GEMINI 8-meter telescopes design

    NASA Technical Reports Server (NTRS)

    St. Clair Dinger, Ann

    1993-01-01

    The GEMINI 8-meter Telescopes Project is designing twin 8-meter telescopes to be located in Hawaii and Chile. The GEMINI telescopes will have interchangeable secondary mirrors for use in the visible and IR. The APART/PADE program is being used to evaluate the effective IR emissivity of the IR configuration plus enclosure as a function of mirror contamination at three IR wavelengths. The goal is to design a telescope whose effective IR emissivity is no more than 2 percent when the mirrors are clean.

  12. Gemini 4 astronauts relax aboard Navy helicopter after recovery

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Gemini 4 astronauts, James A. McDivitt (right), command pilot, and Edward H. White II, (left), pilot, relax aboard a U.S. Navy helicopter on their way to the aircraft carrier U.S.S. Wasp after recovery from the Gemini 4 spacecraft. They had been picked up out of the Atlantic Ocean following a successful splashdown (33532); White (left) and McDivitt listen to the voice of President Lyndon B. Johnson as he congratulated them by telephone on the successful mission. They are shown aboard the carrier U.S.S. Wasp just after their recovery (33533).

  13. Performance of the Gemini Planet Imager's adaptive optics system.

    PubMed

    Poyneer, Lisa A; Palmer, David W; Macintosh, Bruce; Savransky, Dmitry; Sadakuni, Naru; Thomas, Sandrine; Véran, Jean-Pierre; Follette, Katherine B; Greenbaum, Alexandra Z; Ammons, S Mark; Bailey, Vanessa P; Bauman, Brian; Cardwell, Andrew; Dillon, Daren; Gavel, Donald; Hartung, Markus; Hibon, Pascale; Perrin, Marshall D; Rantakyrö, Fredrik T; Sivaramakrishnan, Anand; Wang, Jason J

    2016-01-10

    The Gemini Planet Imager's adaptive optics (AO) subsystem was designed specifically to facilitate high-contrast imaging. A definitive description of the system's algorithms and technologies as built is given. 564 AO telemetry measurements from the Gemini Planet Imager Exoplanet Survey campaign are analyzed. The modal gain optimizer tracks changes in atmospheric conditions. Science observations show that image quality can be improved with the use of both the spatially filtered wavefront sensor and linear-quadratic-Gaussian control of vibration. The error budget indicates that for all targets and atmospheric conditions AO bandwidth error is the largest term.

  14. Distributed user support and the Gemini Observatory help desk

    NASA Astrophysics Data System (ADS)

    Chan, Simon; Puxley, Phil J.

    2000-07-01

    The Gemini Observatory HelpDesk was activated early in 2000 to aid in the rapid and accurate resolution of queries concerning the Gemini telescopes and their capabilities. This system co- ordinates user support amongst staff within the Observatory and at National Offices in each partner country. The HelpDesk is based on a commercial product from Remedy Corporation that logs, tracks, forwards and escalates queries and self- generates a knowledgebase of previously asked questions. Timestamping of these events in the life cycle of a request and analysis of associated information provides valuable feedback on the static web content and performance of user support.

  15. THE GEMINI SPECTRAL LIBRARY OF NEAR-IR LATE-TYPE STELLAR TEMPLATES AND ITS APPLICATION FOR VELOCITY DISPERSION MEASUREMENTS

    SciTech Connect

    Winge, Claudia

    2009-11-01

    We present a spectroscopic library of late spectral type stellar templates in the near-IR range 2.15-2.42 {mu}m, at R = 5300-5900 resolution, oriented to support stellar kinematics studies in external galaxies, such as the direct determination of the masses of supermassive black holes in nearby active (or non-active) galaxies. The combination of high spectral resolution and state-of-the-art instrumentation available in 8 m class telescopes has made the analysis of circumnuclear stellar kinematics using the near-IR CO band heads one of the most used techniques for such studies, and this library aims to provide the supporting data sets required by the higher spectral resolution and larger spectral coverage currently achieved with modern near-IR spectrographs. Examples of the application for kinematical analysis are given for data obtained with two Gemini instruments, but the templates can be easily adjusted for use with other near-IR spectrographs at similar or lower resolution. The example data sets are also used to revisit the 'template mismatch' effect and the dependence of the velocity dispersion values obtained from the fitting process with the characteristics of the stellar templates. The library is available in electronic form from the Gemini Web pages.

  16. GEMINI-GMOS spectroscopy in the Antlia cluster

    NASA Astrophysics Data System (ADS)

    Faifer, F.; Smith Castelli, A. V.; Bassino, L. P.; Richtler, T.; Cellone, S. A.

    : We present preliminary results of a spectroscopic study performed in the Antlia cluster through GEMINI-GMOS data. They are related with new radial velocities that allow us to confirm the cluster membership of several new faint galaxies, as well as to identify very interesting background objects.

  17. Gemini 12 crew arrives aboard U.S.S. Wasp

    NASA Technical Reports Server (NTRS)

    1966-01-01

    A happy Gemini 12 prime crew arrives aboard the aircraft carrier, U.S.S. Wasp. Astronauts James A. Lovell Jr. (left), command pilot, and Edwin E. Aldrin Jr., pilot, had just been picked up from the splashdown area by helicopter.

  18. Designing Scalable PGAS Communication Subsystems on Cray Gemini Interconnect

    SciTech Connect

    Vishnu, Abhinav; Daily, Jeffrey A.; Palmer, Bruce J.

    2012-12-26

    The Cray Gemini Interconnect has been recently introduced as a next generation network architecture for building multi-petaflop supercomputers. Cray XE6 systems including LANL Cielo, NERSC Hopper, ORNL Titan and proposed NCSA BlueWaters leverage the Gemini Interconnect as their primary Interconnection network. At the same time, programming models such as the Message Passing Interface (MPI) and Partitioned Global Address Space (PGAS) models such as Unified Parallel C (UPC) and Co-Array Fortran (CAF) have become available on these systems. Global Arrays is a popular PGAS model used in a variety of application domains including hydrodynamics, chemistry and visualization. Global Arrays uses Aggregate Re- mote Memory Copy Interface (ARMCI) as the communication runtime system for Remote Memory Access communication. This paper presents a design, implementation and performance evaluation of scalable and high performance communication subsystems on Cray Gemini Interconnect using ARMCI. The design space is explored and time-space complexities of commu- nication protocols for one-sided communication primitives such as contiguous and uniformly non-contiguous datatypes, atomic memory operations (AMOs) and memory synchronization is presented. An implementation of the proposed design (referred as ARMCI-Gemini) demonstrates the efficacy on communication primitives, application kernels such as LU decomposition and full applications such as Smooth Particle Hydrodynamics (SPH) application.

  19. Gemini photographs of the world: A complete index

    NASA Technical Reports Server (NTRS)

    Giddings, L. E.

    1977-01-01

    The most authoritative catalogs of photographs of all Gemini missions are assembled. Included for all photographs are JSC (Johnson Space Center) identification number, percent cloud cover, geographical area in sight, and miscellaneous information. In addition, details are given on cameras, filters, films, and other technical details.

  20. Gemini high-resolution optical spectrograph conceptual design

    NASA Astrophysics Data System (ADS)

    Szeto, Kei; McConnachie, Alan; Anthony, André; Bohlender, David; Crampton, David; Desaulniers, Pierre; Dunn, Jennifer; Hardy, Tim; Hill, Alexis; Monin, Dmitry; Pazder, John; Schwab, Christian; Spano, Paola; Starkenburg, Else; Thibault, Simon; Walker, Gordon; Venn, Kim; Zhang, Hu

    2012-09-01

    A multiplexed moderate resolution (R = 34,000) and a single object high resolution (R = 90,000) spectroscopic facility for the entire 340 - 950nm wavelength region has been designed for Gemini. The result is a high throughput, versatile instrument that will enable precision spectroscopy for decades to come. The extended wavelength coverage for these relatively high spectral resolutions is achieved by use of an Echelle grating with VPH cross-dispersers and for the R = 90,000 mode utilization of an image slicer. The design incorporates a fast, efficient, reliable system for acquiring targets over the7 arcmin field of Gemini. This paper outlines the science case development and requirements flow-down process that leads to the configuration of the HIA instrument and describes the overall GHOS conceptual design. In addition, this paper discusses design trades examined during the conceptual design study instrument group of the Herzberg Institute of Astrophysics has been commissioned by the Gemini Observatory as one of the three competing organizations to conduct a conceptual design study for a new Gemini High-Resolution Optical Spectrograph (GHOS). This paper outlines the science case development and requirements flow-down process that leads to the configuration of the HIA instrument and describes the overall GHOS conceptual design. In addition, this paper discusses design trades examined during the conceptual design study.

  1. Classification of 3 DES supernovae by Gemini-North

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Foley, R. J.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; Gladney, L.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.; Childress, M.; D'Andrea, C.; Smith, M.; Sullivan, M.

    2015-11-01

    We report optical spectroscopy of 3 supernovae discovered by the Dark Energy Survey. The spectra (380-820nm) were obtained using GMOS on Gemini-North. Object classification was performed using SNID (Blondin & Tonry, 2007, ApJ, 666, 1024) and superfit (Howell et al, 2005, ApJ, 634, 119), the details of which are reported in the table below.

  2. Gemini 8 prime and backup crews during press conference

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Gemini 8 prime and backup crews during press conference. Left to right are Astronauts David R. Scott, prime crew pilot; Neil A. Armstrong, prime crew command pilot; Charles Conrad Jr., backup crew command pilot; and Richard F. Gordon Jr., backup crew pilot.

  3. Gemini Series Experiment Data Reduction and Storage Techniques

    SciTech Connect

    R. A. Berglin

    2011-11-01

    The presentation covers data formats expected from Gemini experiments; data quick look vs. in-depth analysis; iPDV object-oriented data storage; iPDV's traceability of analysis results; optimizing object memory usage in iPDV; and long-term archival of data objects by iPDV.

  4. Astrometric Calibration of the Gemini NICI Planet-Finding Campaign

    NASA Astrophysics Data System (ADS)

    Hayward, Thomas L.; Biller, Beth A.; Liu, Michael C.; Nielsen, Eric L.; Wahhaj, Zahed; Chun, Mark; Ftaclas, Christ; Hartung, Markus; Toomey, Douglas W.

    2014-12-01

    We describe the astrometric calibration of the Gemini NICI Planet-Finding Campaign. The Campaign requires a relative astrometric accuracy of ≈20 mas across multiyear timescales in order to distinguish true companions from background stars by verifying common proper motion and parallax with their parent stars. The calibration consists of a correction for instrumental optical image distortion, plus on-sky imaging of astrometric fields to determine the pixel scale and image orientation. We achieve an accuracy of lsim7 mas between the center and edge of the 18'' NICI field, meeting the 20 mas requirement. Most of the Campaign data in the Gemini Science Archive are accurate to this level but we identify a number of anomalies and present methods to correct the errors. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc. under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  5. Novel fluorinated gemini surfactants with γ-butyrolactone segments.

    PubMed

    Kawase, Tokuzo; Okada, Kazuyuki; Oida, Tatsuo

    2015-01-01

    In this work, novel γ-butyrolactone-type monomeric and dimeric (gemini) surfactants with a semifluoroalkyl group [Rf- (CH2)3-; Rf = C4F9, C6F13, C8F17] as the hydrophobic group were successfully synthesized. Dimethyl malonate was dimerized or connected using Br(CH2)sBr (s = 0, 1, 2, 3) to give tetraesters, and they were bis-allylated. Radical addition of fluoroalkyl using Rf-I and an initiator, i.e., 2,2'-azobisisobutyronitrile for C4F9 or di-t-butyl peroxide for C6F13 and C8F17, was perform at high temperature, with prolonged heating, to obtain bis(semifluoroalkyl)-dilactone diesters. These dilactone diesters were hydrolyzed using KOH/EtOH followed by decarboxylation in AcOH to afford γ-butyrolactonetype gemini surfactants. Common 1 + 1 semifluoroalkyl lactone surfactants were synthesized using the same method. Their surfactant properties [critical micelle concentration (CMC), γCMC, pC20, ΓCMC, and AG] were investigated by measuring the surface tension of the γ-hydroxybutyrate form prepared in aqueous tetrabutylammonium hydroxide solution. As expected, the CMC values of the gemini surfactants were more than one order of magnitude smaller than those of the corresponding 1 + 1 surfactants. Other properties also showed the excellent ability of the gemini structure to reduce the surface tension. These surfactants were easily and quantitatively recovered by acidification. The monomeric surfactant was recovered in the γ-hydroxybutyric acid form, and the gemini surfactant as a mixture of γ-butyrolactone and γ-hydroxybutyric acid forms.

  6. Gemini Planet Imager: Preliminary Design Report

    SciTech Connect

    Macintosh, B

    2007-05-10

    For the first time in history, direct and indirect detection techniques have enabled the exploration of the environments of nearby stars on scales comparable to the size of our solar system. Precision Doppler measurements have led to the discovery of the first extrasolar planets, while high-contrast imaging has revealed new classes of objects including dusty circumstellar debris disks and brown dwarfs. The ability to recover spectrophotometry for a handful of transiting exoplanets through secondary-eclipse measurements has allowed us to begin to study exoplanets as individual entities rather than points on a mass/semi-major-axis diagram and led to new models of planetary atmospheres and interiors, even though such measurements are only available at low SNR and for a handful of planets that are automatically those most modified by their parent star. These discoveries have galvanized public interest in science and technology and have led to profound new insights into the formation and evolution of planetary systems, and they have set the stage for the next steps--direct detection and characterization of extrasolar Jovian planets with instruments such as the Gemini Planet Imager (GPI). As discussed in Volume 1, the ability to directly detect Jovian planets opens up new regions of extrasolar planet phase space that in turn will inform our understanding of the processes through which these systems form, while near-IR spectra will advance our understanding of planetary physics. Studies of circumstellar debris disks using GPI's polarimetric mode will trace the presence of otherwise-invisible low-mass planets and measure the build-up and destruction of planetesimals. To accomplish the science mission of GPI will require a dedicated instrument capable of achieving contrast of 10{sup -7} or more. This is vastly better than that delivered by existing astronomical AO systems. Currently achievable contrast, about 10{sup -5} at separations of 1 arc second or larger, is

  7. 77 K Fatigue Crack Growth Rate of Modified CF8M Stainless Steel Castings

    SciTech Connect

    Walsh, R. P.; Toplosky, V. J.; Han, K.; Heitzenroeder, P. J.; Nelson, B. E.

    2006-03-31

    The National Compact Stellerator Experiment (NCSX) is the first of a new class of stellarators. The modular superconducting coils in the NCSX have complex geometry that are manufactured on cast stainless steel (modified CF8M) winding forms. Although CF8M castings have been used before at cryogenic temperature there is limited data available for their mechanical properties at low temperatures. The fatigue life behavior of the cast material is vital thus a test program to generate data on representative material has been conducted. Fatigue test specimens have been obtained from key locations within prototype winding forms to determine the 77 K fatigue crack growth rate. The testing has successfully developed a representative database that ensures confident design. The measured crack growth rates are analyzed in terms of the Paris law parameters and the crack growth properties are related to the materials microstructure.

  8. Remaining Sites Verification Package for the 100-F-26:12, 1.8-m (72-in.) Main Process Sewer Pipeline, Waste Site Reclassification Form 2007-034

    SciTech Connect

    J. M. Capron

    2008-04-29

    The 100-F-26:12 waste site was an approximately 308-m-long, 1.8-m-diameter east-west-trending reinforced concrete pipe that joined the North Process Sewer Pipelines (100-F-26:1) and the South Process Pipelines (100-F-26:4) with the 1.8-m reactor cooling water effluent pipeline (100-F-19). In accordance with this evaluation, the verification sampling results support a reclassification of this site to Interim Closed Out. The results of verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.

  9. 8 Meter Advanced Technology Large-Aperture Space Telescope (ATLAST-8m)

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2010-01-01

    ATLAST-8m (Advanced Technology Large Aperture Space Telescope) is a proposed 8-meter monolithic UV/optical/NIR space observatory (wavelength range 110 to 2500 nm) to be placed in orbit at Sun-Earth L2 by NASA's planned Ares V heavy lift vehicle. Given its very high angular resolution (15 mas @ 500 nm), sensitivity and performance stability, ATLAST-8m is capable of achieving breakthroughs in a broad range of astrophysics including: Is there life elsewhere in the Galaxy? An 8-meter UVOIR observatory has the performance required to detect habitability (H2O, atmospheric column density) and biosignatures (O2, O3, CH4) in terrestrial exoplanet atmospheres, to reveal the underlying physics that drives star formation, and to trace the complex interactions between dark matter, galaxies, and intergalactic medium. The ATLAST Astrophysics Strategic Mission Concept Study developed a detailed point design for an 8-m monolithic observatory including optical design; structural design/analysis including primary mirror support structure, sun shade and secondary mirror support structure; thermal analysis; spacecraft including structure, propulsion, GN&C, avionics, power systems and reaction wheels; mass and power budgets; and system cost. The results of which were submitted by invitation to NRC's 2010 Astronomy & Astrophysics Decadal Survey.

  10. Solar System Research with the Spacewatch 1.8-m Telescope

    NASA Technical Reports Server (NTRS)

    McMillan, Robert S.

    2001-01-01

    During this grant period, the 1.8-m Spacewatch telescope was put into routine operation to search for asteroids and comets ranging in location from near-Earth space to regions beyond the orbit of Neptune. All of these classes of objects can be detected simultaneously with our uniform scanning procedures. We are studying near Earth objects (NEOs), main belt asteroids, comets, Centaurs, and trans-Neptunian objects (TNOs), as well as the interrelationships of these classes and their bearing on the origin and evolution of the solar system. The Spacewatch 1.8-meter telescope is sensitive to V(mag) < 22.6 in sidereal scanning mode and is able to reach even fainter in longer 'staring' exposures, with a field of view 0.5 degrees square. These faint limits make the operation of the Spacewatch 1.8-m telescope complementary to asteroid surveys being done by other groups. Specifically, EAs smaller than 100 m in diameter and small main belt asteroids can be found, as well as more distant objects such as Centaurs/Scattered Disk Objects (SDOs) and TNOs. The 1.8-m telescope is also being used to do recoveries and astrometry of recently-discovered asteroids that subsequently become too faint for the other groups before good orbits are established.

  11. Detection of interleukin-8 mRNA and protein in human colorectal carcinoma cells.

    PubMed

    Brew, R; Southern, S A; Flanagan, B F; McDicken, I W; Christmas, S E

    1996-11-01

    Interleukin-8 (IL-8) is a member of the chemokine family of pro-inflammatory chemotactic cytokines and is secreted by some human colorectal carcinoma cell lines. We have used in situ hybridisation and immunohistochemistry to determine whether IL-8 mRNA and protein, respectively, are produced by human colorectal carcinoma cells in vivo. IL-8 mRNA was detected within the cytoplasm of tumour cells in all nine samples tested, including that of a tumour which had metastasised to a lymph node. Non-involved colonic mucosa within the same tissue blocks showed much weaker labelling. IL-8 protein was detected in 74% (23/31) of tumour samples and was mainly localised to the tumour cell cytoplasm. In 30% of cases, staining was heterogeneous, with between 1 and 30% of cells being positive. In some tumour cells, IL-8 showed a perinuclear distribution resembling that found by in situ hybridisation. Some infiltrating leucocytes, endothelial cells and fibroblast-like cells within the tumour sections were also positive for IL-8 mRNA and protein. The possibilities that colorectal tumours produce IL-8 to aid invasion and/or metastasis or as a tumour growth factor are discussed.

  12. The Gemini NICI planet-finding campaign: The offset ring of HR 4796 A

    NASA Astrophysics Data System (ADS)

    Wahhaj, Zahed; Liu, Michael C.; Biller, Beth A.; Nielsen, Eric L.; Hayward, Thomas L.; Kuchner, Marc; Close, Laird M.; Chun, Mark; Ftaclas, Christ; Toomey, Douglas W.

    2014-07-01

    We present J,H, CH4 short (1.578 μm), CH4 long (1.652 μm) and Ks-band images of the dust ring around the 10 Myr old star HR 4796 A obtained using the Near Infrared Coronagraphic Imager (NICI) on the Gemini-South 8.1 m Telescope. Our images clearly show for the first time the position of the star relative to its circumstellar ring thanks to NICI's translucent focal plane occulting mask. We employ a Bayesian Markov chain Monte Carlo method to constrain the offset vector between the two. The resulting probability distribution shows that the ring center is offset from the star by 16.7 ± 1.3 milliarcseconds along a position angle of 26 ± 3°, along the PA of the ring, 26.47 ± 0.04°. We find that the size of this offset is not large enough to explain the brightness asymmetry of the ring. The ring is measured to have mostly red reflectivity across the JHKs filters, which seems to indicate micron-sized grains. Just like Neptune's 3:2 and 2:1 mean-motion resonances delineate the inner and outer edges of the classical Kuiper belt, we find that the radial extent of the HR 4796 A and the Fomalhaut rings could correspond to the 3:2 and 2:1 mean-motion resonances of hypothetical planets at 54.7 AU and 97.7 AU in the two systems, respectively. A planet orbiting HR 4796 A at 54.7 AU would have to be less massive than 1.6 MJup so as not to widen the ring too much by stirring. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).Tables 5 and 6 are available in electronic form at

  13. Kinetics of aqueous lubrication in the hydrophilic hydrogel Gemini interface.

    PubMed

    Dunn, Alison C; Pitenis, Angela A; Urueña, Juan M; Schulze, Kyle D; Angelini, Thomas E; Sawyer, W Gregory

    2015-12-01

    The exquisite sliding interfaces in the human body share the common feature of hydrated dilute polymer mesh networks. These networks, especially when they constitute a sliding interface such as the pre-corneal tear film on the ocular interface, are described by the molecular weight of the polymer chains and a characteristic size of a minimum structural unit, the mesh size, ξ. In a Gemini interface where hydrophilic hydrogels are slid against each other, the aqueous lubrication behavior has been shown to be a function of sliding velocity, introducing a sliding timescale competing against the time scales of polymer fluctuation and relaxation at the surface. In this work, we examine two recent studies and postulate that when the Gemini interface slips faster than the single-chain relaxation time, chains must relax, suppressing the amplitude of the polymer chain thermal fluctuations.

  14. Kinetics of aqueous lubrication in the hydrophilic hydrogel Gemini interface.

    PubMed

    Dunn, Alison C; Pitenis, Angela A; Urueña, Juan M; Schulze, Kyle D; Angelini, Thomas E; Sawyer, W Gregory

    2015-12-01

    The exquisite sliding interfaces in the human body share the common feature of hydrated dilute polymer mesh networks. These networks, especially when they constitute a sliding interface such as the pre-corneal tear film on the ocular interface, are described by the molecular weight of the polymer chains and a characteristic size of a minimum structural unit, the mesh size, ξ. In a Gemini interface where hydrophilic hydrogels are slid against each other, the aqueous lubrication behavior has been shown to be a function of sliding velocity, introducing a sliding timescale competing against the time scales of polymer fluctuation and relaxation at the surface. In this work, we examine two recent studies and postulate that when the Gemini interface slips faster than the single-chain relaxation time, chains must relax, suppressing the amplitude of the polymer chain thermal fluctuations. PMID:26614802

  15. Gemini Observatory Takes its Local Communities on an Expanding Journey

    NASA Astrophysics Data System (ADS)

    Harvey, Janice; Michaud, Peter

    2012-08-01

    Currently in its 7th year (2011) Hawaii's annual Journey through the Universe (JttU) program is a flagship Gemini Observatory public education/outreach initiative involving a broad cross-section of the local Hawai'i Island astronomical community, the public, educators, businesses, local government officials, and thousands of local students. This paper describes the program, its history, planning, implementation, as well as the program's objectives and philosophy. The success of this program is documented here, as measured by continuous and expanding engagement of educators, the community, and the public, along with formal evaluation feedback and selected informal verbal testimony. The program's success also serves as justification for the planned adaptation of a version of the program in Chile in 2011 (adapted for Chilean educational and cultural differences). Finally, lessons learned are shared which have refined the program for Gemini's host communities but can also apply to any institution wishing to initiate a similar program.

  16. Gemini's instrumentation program: latest results and long-range plan

    NASA Astrophysics Data System (ADS)

    Boccas, Maxime; Kleinman, S. J.; Goodsell, Stephen; Tollestrup, Eric; Adamson, Andrew; Arriagada, Gustavo; Christou, Julian; Gonzalez, Patricio; Hanna, Kevin; Hartung, Markus; Lazo, Manuel; Mason, Rachel; Neichel, Benoît; Perez, Gabriel; Simons, Doug; Walls, Brian; White, John

    2012-09-01

    The Gemini Observatory is going through an extraordinary time with astronomical instrumentation. New powerful capabilities are delivered and are soon entering scientific operations. In parallel, new instruments are being planned and designed to align the strategy with community needs and enhance the competitiveness of the Observatory for the next decade. We will give a broad overview of the instrumentation program, focusing on achievements, challenges and strategies within a scientific, technical and management perspective. In particular we will discuss the following instruments and projects (some will have dedicated detailed papers in this conference): GMOS-CCD refurbishment, FLAMINGOS-2, GeMS (MCAO system and imager GSAOI), GPI, new generation of A&G, GRACES (fiber feed to CFHT ESPaDOnS) and GHOS (Gemini High-resolution Optical Spectrograph), and provide some updates about detector controllers, mid-IR instruments, Altair, GNIRS, GLAO and future workhorse instruments.

  17. Synthesis of organic rectorite with novel Gemini surfactants for copper removal

    NASA Astrophysics Data System (ADS)

    Han, Guocheng; Han, Yang; Wang, Xiaoying; Liu, Shijie; Sun, Runcang

    2014-10-01

    Three novel Gemini surfactants were used to prepare organic rectorite (OREC) under microwave irradiation, in comparison with single-chain surfactant ester quaternary ammonium salt (EQAS) and cetyltrimethyl ammonium bromide (CTAB). The structure and morphology of OREC were characterized by XRD, BET, FT-IR, TEM and TGA. The removal of Cu2+ on OREC from aqueous solution was performed. The results reveal that Gemini surfactants modified REC had larger interlayer distance and higher surface area than single-chain surfactants EQAS and CTAB, and the increasing amount or chain length of Gemini surfactants led to larger layer spacing and higher adsorption capacities. The adsorption behavior of Gemini surfactant modified REC can be better described by Freundlich adsorption isotherm model, with a maximum adsorption capacity of 15.16 mg g-1. The desorption and regeneration experiments indicate good reuse property of Gemini modified REC adsorbent. Therefore, this study may widen the utilization of Gemini surfactants modified layered silicates.

  18. Characterization and testing of FLAMINGOS-2: the Gemini facility near-infrared multi-object spectrometer and wide-field imager

    NASA Astrophysics Data System (ADS)

    Raines, Steven N.; Eikenberry, Stephen S.; Bandyopadhyay, Reba M.; Julian, Jeffrey A.; Hanna, Kevin T.; Warner, Craig D.; Julian, Roger E.; Bennett, J. Greg; DeWitt, Curtis N.; Frommeyer, Skip; Gonzalez, Anthony; Herlevich, Michael D.; Murphey, Charles

    2008-07-01

    FLAMINGOS-2 is a near-infrared wide-field imager and fully cryogenic multi-object spectrometer for Gemini Observatory being built by the University of Florida. FLAMINGOS-2 can simultaneously carry 9 custom cryogenic multi-object slit masks exchangeable without thermally cycling the entire instrument. Three selectable grisms provide resolving powers which are ~1300 to ~3000 over the entire spectrograph bandpass of 0.9-2.5 microns. We present and discuss characterization data for FLAMINGOS-2 including imaging throughput, image quality, spectral performance, and noise performance. After a lengthy integration process, we expect that FLAMINGOS-2 will be in the midst of commissioning at Gemini South by the fall of 2008.

  19. Interaction effects on galaxy pairs with Gemini/GMOS - II: oxygen abundance gradients

    NASA Astrophysics Data System (ADS)

    Rosa, D. A.; Dors, O. L.; Krabbe, A. C.; Hägele, G. F.; Cardaci, M. V.; Pastoriza, M. G.; Rodrigues, I.; Winge, C.

    2014-11-01

    In this paper, we derive oxygen abundance gradients from H II regions located in 11 galaxies in eight systems of close pairs. Long-slit spectra in the range 4400-7300 Å were obtained with the Gemini Multi-Object Spectrograph at Gemini South (GMOS-S). Spatial profiles of oxygen abundance in the gaseous phase along galaxy discs were obtained using calibrations based on strong emission lines (N2 and O3N2). We found oxygen gradients to be significantly flatter for all the studied galaxies than those in typical isolated spiral galaxies. Four objects in our sample, AM 1219A, AM 1256B, AM 2030A and AM 2030B, show a clear break in the oxygen abundance at galactocentric radius R/R25 between 0.2 and 0.5. For AM 1219A and AM 1256B, we found negative slopes for the inner gradients, and for AM 2030B, we found a positive slope. All three cases show a flatter behaviour to the outskirts of the galaxies. For AM 2030A, we found a positive slope for the outer gradient, while the inner gradient is almost compatible with a flat behaviour. We found a decrease of star formation efficiency in the zone that corresponds to the oxygen abundance gradient break for AM 1219A and AM 2030B. For the former, a minimum in the estimated metallicities was found very close to the break zone, which could be associated with a corotation radius. However, AM 1256B and AM 2030A, present a star formation rate maximum but not an extreme oxygen abundance value. All four interacting systems that show oxygen gradient breaks have extreme SFR values located very close to break zones.The H II regions located in close pairs of galaxies follow the same relation between the ionization parameter and the oxygen abundance as those regions in isolated galaxies.

  20. Gemini 8 crew stands on deck of recovery vessel

    NASA Technical Reports Server (NTRS)

    1966-01-01

    The Gemini 8 crew stands on the deck of the recovery vessel, the U.S.S. Leonard F. Mason, with three U.S. Air Force pararescue men. Left to right (standing) are Astronaut Neil A. Armstrong, command pilot; A/2C Glenn M. Moore; Astronaut David R. Scott, pilot; kneeling, left to right are A/1C Eldridge M. Neal; and S/Sgt Larry D. Huyett.

  1. Gemini's protected silver coatings: first two years in operation

    NASA Astrophysics Data System (ADS)

    Vucina, Tomislav; Boccas, Maxime; Araya, Claudio; Ahhee, Clayton

    2006-06-01

    The Gemini twins were the first large modern telescopes to receive protected Silver coatings on their mirrors in 2004. We report the performance evolution of these 4-layer coatings in terms of reflectivity and emissivity. We evaluate the durability of these thin films by comparison to the evolution of some samples that we have produced and exposed since 2002. Finally, we will explain our maintenance plan.

  2. Effect of liquid channeling on a 1.8-m distillation sieve tray

    SciTech Connect

    Proctor, S.J.; Biddulph, M.W.; Krishnamurthy, K.R.

    1998-06-01

    This paper describes an experimental investigation designed to establish the extent of the effects of liquid channeling and stagnant zones on the efficiency of a 1.8-m diameter sieve tray. The method used is to compare performance, in the same column and using the same system, with a novel tray which is known, from hydraulic studies, to remove stagnant zones. It is found that there is an observable loss in efficiency in the sieve tray, particularly at heavy loadings, and this will have implications for designers specifying high-capacity trays for new or upgraded columns.

  3. On-sky validation of an optimal LQG control with vibration mitigation: from the CANARY Multi-Object Adaptive Optics demonstrator to the Gemini Multi-Conjugated Adaptive Optics facility.

    NASA Astrophysics Data System (ADS)

    Sivo, Gaetano; Kulcsár, Caroline; Conan, Jean-Marc; Raynaud, Henri-François; Gendron, Éric; Basden, Alastair; Gratadour, Damien; Morris, Tim; Petit, Cyril; Meimon, Serge; Rousset, Gérard; Garrel, Vincent; Neichel, Benoit; van Dam, Marcos; Marin, Eduardo; Carrasco, Rodrigo; Schirmer, Mischa; Rambold, William; Moreno, Cristian; Montes, Vanessa; Hardie, Kayla; Trujillo, Chad

    2015-01-01

    Adaptive optics provides real time correction of wavefront perturbations on ground-based telescopes and allow to reach the diffraction limit performances. Optimizing control and performance is a key issue for ever more demanding instruments on ever larger telescopes affected not only by atmospheric turbulence, but also by vibrations, windshake and tracking errors. Linear Quadratic Gaussian control achieves optimal correction when provided with a temporal model of the disturbance. We present in this paper the first on-sky results of a Kalman filter based LQG control with vibration mitigation on the CANARY instrument at the Nasmyth platform of the 4.2-m William Herschel Telescope (La Palma, Spain). The results demonstrate a clear improvement of performance for full LQG compared with standard integrator control, and assess the additional improvement brought by vibration filtering with a tip-tilt model identified from on-sky data (by 10 points of Strehl ratio), thus validating the strategy retained on the instrument SPHERE (eXtreme-AO system for extra-solar planets detection and characterization) at the VLT. The MOAO on-sky pathfinder CANARY features two AO configurations that have both been tested: single- conjugated AO and multi-object AO with NGS and NGS+ Rayleigh LGS, together with vibration mitigation on tip and tilt modes. We finally present the ongoing development done to commission such a control law on a regular Sodium laser Multi-Conjuagated Adaptive Optics (MCAO) system GeMS at the 8-m Gemini South Telescope. This implementation does not require new hardware and is already available in the real-time computer.

  4. On the Shoulders of Titans: A History of Project Gemini

    NASA Technical Reports Server (NTRS)

    Hacker, B. C.

    1977-01-01

    Gemini was the intermediate manned space flight program between America's first steps into space with Mercury and the manned lunar expeditions of Apollo. Because of its position between these two other efforts, Gemini is probably less remembered. Still, it more than had its place in man's progress into this new frontier. Gemini accomplishments were manyfold. They included many firsts: first astronaut-controlled maneuvering in space; first rendezvous in space of one spacecraft with another; first docking of one spacecraft with a propulsive stage and use of that stage to transfer man to high altitude; first traverse of man into the earth's radiation belts; first extended manned flights of a week or more in duration; first extended stays of man outside his spacecraft; first controlled reentry and precision landing; and many more. These achievements were significant in ways one cannot truly evaluate even today, but two things stand out: (1) it was the time when America caught up and surpassed the Soviet Union in manned space flight, and (2) these demonstrations of capability were an absolute prerequisite to the phenomenal Apollo accomplishments then yet to come.

  5. Gemini - John W. Young in Rendezvous Docking Simulator

    NASA Technical Reports Server (NTRS)

    1963-01-01

    Astronaut John Young (above) was one of 14 astronauts, 8 NASA test pilots, and 2 McDonnell test pilots who took part in simulator studies. Young piloted the simulator on November 12, 1963 Arthur Vogeley wrote: 'Many of the astronauts have flown this simulator in support of the Gemini studies and they, without exception, appreciated the realism of the visual scene. The simulator has also been used in the development of pilot techniques to handle certain jet malfunctions in order that aborts could be avoided. In these situations large attitude changes are sometimes necessary and the false motion cues that were generated due to earth gravity were somewhat objectionable; however, the pilots were readily able to overlook these false motion cues in favor of the visual realism.' Roy F. Brissenden wrote:'The basic Gemini control studies developed the necessary techniques and demonstrated the ability of human pilots to perform final space docking with the specified Gemini-Agena systems using only visual references. ... Results... showed that trained astronauts can effect the docking with direct acceleration control and even with jet malfunctions as long as good visual conditions exist.... Probably more important than data results was the early confidence that the astronauts themselves gained in their ability to perform the maneuver in the ultimate flight mission.'

  6. Easier Phase IIs: Recent Improvements to the Gemini User Tools

    NASA Astrophysics Data System (ADS)

    Miller, Bryan; Nuñez, A.

    2013-01-01

    During 2011 and 2012 Gemini Observatory undertook a significant project to improve the software tools used by investigators to propose for and prepare observations. The main goal was to make the definition of observation details (the Phase II process) easier and faster. The main initiatives included rewriting the observing proposal tool (Phase I Tool) and making several major improvements to the Observing Tool, including automatic settings for arc and flat exposures, automatic guide star selection for all instruments and wavefront sensors, and more complete initial template observations with capabilities for simultaneous editing of many observations. This poster explains these major changes as well as outlines future development plans. The Gemini Observatory is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  7. Gemini 9-A spacecraft touches down in the Atlantic at end of mission

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Gemini 9-A space flight is concluded as the Gemini 9 spacecraft touches down in the Atlantic. In this view its parachute is still deployed as the spacecraft hits the water (34117); Astronauts Thomas Stafford (right) and Eugene Cernan wave to the crowd aboard the aircraft carrier U.S.S. Wasp as they emerge from their Gemini 9 capsule. John C. Stonesifer (far right), with the Manned Spacecraft Center's Landing and Recovery Division, was on board to greet the astronauts (34118).

  8. Novel Synthesis of Anionic Gemini Surfactants from 1, 4-Diol as a Key Block Material.

    PubMed

    Kawase, Tokuzo; Nakagawa, Mami; Higuchi, Yuuya; Oida, Tatsuo

    2015-01-01

    In this study, a series of all-hydrocarbon anionic gemini surfactants containing COOH (adipic acid-type and suberic acid-type), SO3Na, OSO3Na, and OP=O(OH)2 functional groups was developed from 1,4-diol and 1,4-diketone as a key block material. The effect of the surfactant head groups on the surface properties was investigated by surface tension and surface pressure-area (π-A) measurements. We found that the critical micelle concentrations (CMC) of the studied geminis were smaller by one order of magnitude than those of the corresponding 1+l-type surfactants. From π-A measurements, the limiting areas of COOH-type geminis were less than twofold of the area of the corresponding 1+1-type, which indicates that the gemini structure enabled tighter packing than is possible in surfactants of the 1+l-type. In contrast, the limiting area of the OP=O(OH)2-type gemini was larger than those of the COOH-type geminis. Furthermore, the suberic acid-type gemini showed a smaller limiting area than that of adipic acid-type gemini. Therefore, we can conclude that the flexibility of the gemini at the connecting position has a significant effect on formation of the monolayer at the air/water interface.

  9. 1.8-m solar telescope in China: Chinese Large Solar Telescope

    NASA Astrophysics Data System (ADS)

    Rao, Changhui; Gu, Naiting; Zhu, Lei; Huang, Jinlong; Li, Cheng; Cheng, Yuntao; Liu, Yangyi; Cao, Xuedong; Zhang, Ming; Zhang, Lanqiang; Liu, Hong; Wan, Yongjian; Xian, Hao; Ma, Wenli; Bao, Hua; Zhang, Xiaojun; Guan, Chunlin; Chen, Donghong; Li, Mei

    2015-04-01

    For better understanding and forecasting of solar activity, high resolution observations for the Sun are needed. Therefore, the Chinese Large Solar Telescope (CLST) with a 1.8-m aperture is being built. The CLST is a classic Gregorian configuration telescope with an open structure, alt-azimuth mount, retractable dome, and a large mechanical de-rotator. The optical system with an all reflective design has a field of view of larger than 3 arc-min. The 1.8-m primary mirror is a honeycomb sandwich fused silica lightweight mirror with an ultra lower expansion material and active cooling. The adaptive optics system will be developed to provide the capability for diffraction-limited observations at visible wavelengths. The CLST design and development phase began in 2011 and 2012, respectively. We plan for the CLST's start of commission to be in 2017. A multiwavelength tomographic imaging system, ranging from visible to near-infrared, is considered as the first light scientific instrument. The main system configuration and the corresponding postfocal instruments are described. Furthermore, the latest progress and current status of the CLST are also reported.

  10. The Ages, Metallicities, and Alpha Element Enhancements of Globular Clusters in the Elliptical NGC 5128: A Homogeneous Spectroscopic Study with Gemini/Gemini Multi-Object Spectrograph

    NASA Astrophysics Data System (ADS)

    Woodley, Kristin A.; Harris, William E.; Puzia, Thomas H.; Gómez, Matías; Harris, Gretchen L. H.; Geisler, Doug

    2010-01-01

    We present new integrated light spectroscopy of globular clusters (GCs) in NGC 5128, a nearby giant elliptical galaxy less than 4 Mpc away, in order to measure radial velocities and derive ages, metallicities, and alpha-element abundance ratios. Using the Gemini South 8 meter telescope with the instrument Gemini Multi-Object Spectrograph, we obtained spectroscopy in the range of ~3400-5700 Å for 72 GCs with a signal-to-noise ratio greater than 30 Å-1 and we have also discovered 35 new GCs within NGC 5128 from our radial velocity measurements. We measured and compared the Lick indices from Hδ A through Fe5406 with the single stellar population models of Thomas et al. in order to derive age, metallicity, and [α/Fe] values. We also measure Lick indices for 41 Milky Way GCs from Puzia et al. and Schiavon et al. with the same methodology for direct comparison. Our results show that 68% of the NGC 5128 GCs have old ages (>8 Gyr), 14% have intermediate ages (5-8 Gyr), and 18% have young ages (<5 Gyr). However, when we look at the metallicity of the GCs as a function of age, we find 92% of metal-poor GCs and 56% of metal-rich GCs in NGC 5128 have ages >8 Gyr, indicating that the majority of both metallicity subpopulations of GCs formed earlier, with a significant population of young and metal-rich GCs forming later. Our metallicity distribution function generated directly from spectroscopic Lick indices is clearly bimodal, as is the color distribution of the same set of GCs. Thus, the metallicity bimodality is real and not an artifact of the color to metallicity conversion. However, the metallicity distribution function obtained from comparison with the single stellar population models is consistent with a unimodal, bimodal, or multimodal shape. The [α/Fe] values are supersolar with a mean value of 0.14 ± 0.04, indicating a fast formation timescale. However, the GCs in NGC 5128 are not as [α/Fe] enhanced as the Milky Way GCs also examined in this study. Our measured

  11. The structure of the faint nebulosity and obscuration toward M8, M20, and W28

    NASA Astrophysics Data System (ADS)

    Hartl, H.; Malin, D. F.; MacGillivray, H. T.; Zealey, W. J.

    A study of filamentary nebulosity and dust clouds in the M8, M20, W28 region has been carried out using deep, UKSTU and ESO plate material. An arc of red nebulosity, centred near the W28 supernova remnant and passing across the face of M20 has been noted. Star counts show that W28 is embedded in a dense sheet of material (N0 > 120 cm-3). This sheet appears to be at a distance of less than 2100 pc. One possible interpretation is that the arc of nebulosity is part of a large, 1.5 degree diameter, shell formed by the expansion of the W28 SNR into an inhomogeneous medium.

  12. Memorized chiral arrangement of gemini surfactant assemblies in nanometric hybrid organic-silica helices.

    PubMed

    Ryu, Naoya; Okazaki, Yutaka; Hirai, Kana; Takafuji, Makoto; Nagaoka, Shoji; Pouget, Emilie; Ihara, Hirotaka; Oda, Reiko

    2016-04-30

    Hybrid nanohelices were obtained from silicification of self-assemblies of gemini surfactants with tartrate counterions. The chiral arrangement of these non-chiral gemini surfactants was preserved in the silica matrix even after the counterion exchange for a non-chiral bromide, and was capable of inducing the chiral organisation of a non-chiral dye, methyl orange. PMID:26961377

  13. Giant Micelles of Organoplatinum(II) Gemini Amphiphiles

    PubMed Central

    Maran, Umamageswaran; Conley, Hiram; Frank, Markus; Arif, Atta M.; Orendt, Anita M.; Britt, David; Hlady, Vladimir; Davis, Robert; Stang, Peter J.

    2008-01-01

    Organoplatinum(II) gemini amphiphiles with two different chain lengths are synthesized and characterized. Self-assembly at the air-water interface is investigated as a function of chain length and reduction in surface area by using Langmuir-trough techniques. The Langmuir-trough experiments lead to a conjecture that surface aggregates may be the adsorbing units. Atomic force microscopy on the transferred Langmuir-Schaefer films reveals spontaneous formation of wormlike micellar aggregates. A shear-induced transition and alignment are proposed for the observed effects. PMID:18439034

  14. Participación argentina en el Gemini Observatory

    NASA Astrophysics Data System (ADS)

    Cellone, S. A.; Faifer, F. R.; Smith-Castelli, A. V.; Ferreiro, D.; Ferrero, G.

    Since the beginning of the present century; Argentina has access to two twin telescopes each 8.1m in diameter. The Observatory covers both celestial hemispheres; and is equipped with modern instrumentation spanning from the optical to the mid-infrared. This paper gives a brief description of present instruments as well as those available in the near future; pointing to their possible impact on different research lines. The present situation of the Argentine participation in Gemini is illustrated with a few relevant statistical data; focusing the attention on the new agreement that should be signed by all the partners in 2015. FULL TEXT IN SPANISH

  15. Hot Compression of TC8M-1: Constitutive Equations, Processing Map, and Microstructure Evolution

    NASA Astrophysics Data System (ADS)

    Yue, Ke; Chen, Zhiyong; Liu, Jianrong; Wang, Qingjiang; Fang, Bo; Dou, Lijun

    2016-06-01

    Hot compression of TC8M-1 was carried out under isothermal working conditions with temperature from 1173 K to 1323 K (900 °C to 1050 °C), strain rate from 0.001 to 10/s, and height reduction from 20 to 80 pct (corresponding true strain from 0.22 to 1.61). Constitutive equations were constructed and apparent activation energies of 149.5 and 617.4 kJ/mol were obtained for deformation in the β and upper α/ β phase regions, respectively. Microstructure examination confirmed the dominant role of dynamic recrystallization in the α/ β phase region and that of dynamic recovery in the β phase region, with the occurrence of grain boundary sliding at very low strain rate (0.001/s) in both regions. Based on the dynamic materials model, processing maps were constructed, providing optimal domains for hot working at the temperature of 1253 K (980 °C) and the strain rate of 0.01 to 0.1/s, or at 1193 K to 1213 K (920 °C to 940 °C) and 0.001/s. Moreover, our results indicated that the initial temperature non-uniformity along the specimen axis before compression existed and influenced the strain distribution, which contributed to the abnormal oscillations and/or abrupt rise-up of true stress and inhomogeneous deformation.

  16. Stability Error Budget for an Aggressive Coronagraph on a 3.8 m Telescope

    NASA Technical Reports Server (NTRS)

    Shaklan, Stuart B.; Marchen, Luis; Krist, John; Rud, Mayer

    2011-01-01

    We evaluate in detail the stability requirements for a band-limited coronagraph with an inner working angle as small as 2 lambda/D coupled to an off-axis, 3.8-m diameter telescope. We have updated our methodologies since presenting a stability error budget for the Terrestrial Planet Finder Coronagraph mission that worked at 4 lambda/D and employed an 8th-order mask to reduce aberration sensitives. In the previous work, we determined the tolerances relative to the total light leaking through the coronagraph. Now, we separate the light into a radial component, which is readily separable from a planet signal, and an azimuthal component, which is easily confused with a planet signal. In the current study, throughput considerations require a 4th-order coronagraph. This, combined with the more aggressive working angle, places extraordinarily tight requirements on wavefront stability and opto-mechanical stability. We find that the requirements are driven mainly by coma that leaks around the coronagraph mask and mimics the localized signal of a planet, and pointing errors that scatter light into the background, decreasing SNR. We also show how the requirements would be relaxed if a low-order aberration detection system could be employed.

  17. Test results for the Gemini Planet Imager data reduction pipeline

    NASA Astrophysics Data System (ADS)

    Maire, Jérôme; Perrin, Marshall D.; Doyon, René; Chilcote, Jeffrey; Larkin, James E.; Weiss, Jason L.; Marois, Christian; Konopacky, Quinn M.; Millar-Blanchaer, Maxwell; Graham, James R.; Dunn, Jennifer; Galicher, Raphael; Marchis, Franck; Wiktorowicz, Sloane J.; Labrie, Kathleen; Thomas, Sandrine J.; Goodsell, Stephen J.; Rantakyro, Fredrik T.; Palmer, David W.; Macintosh, Bruce A.

    2012-09-01

    The Gemini Planet Imager (GPI) is a new facility instrument for the Gemini Observatory designed to detect and characterize planets and debris disks orbiting nearby stars; its science camera is a near infrared integral field spectrograph. We have developed a data pipeline for this instrument, which will be made publicly available to the community. The GPI data reduction pipeline (DRP) incorporates all necessary image reduction and calibration steps for high contrast imaging in both the spectral and polarimetric modes, including datacube generation, wavelength solution, astrometric and photometric calibrations, and speckle suppression via ADI and SSDI algorithms. It is implemented in IDL as a flexible modular system, and includes both command line and graphical interface tools including a customized viewer for GPI datacubes. This GPI data reduction pipeline is currently working very well, and is in use daily processing data during the instrument’s ongoing integration and test period at UC Santa Cruz. Here we summarize the results from recent pipeline tests, and present reductions of instrument test data taken with GPI. We will continue to refine and improve these tools throughout the rest of GPI’s testing and commissioning, and they will be released to the community, including both IDL source code and compiled versions that can be used without an IDL license.

  18. The lick-index calibration of the Gemini multi-object spectrographs

    SciTech Connect

    Puzia, Thomas H.; Miller, Bryan W.; Trancho, Gelys; Basarab, Brett; Mirocha, Jordan T.; Butler, Karen E-mail: bmiller@gemini.edu

    2013-06-01

    We present the calibration of the spectroscopic Lick/IDS standard line-index system for measurements obtained with the Gemini Multi-Object Spectrographs known as GMOS-North and GMOS-South. We provide linear correction functions for each of the 25 standard Lick line indices for the B600 grism and two instrumental setups, one with 0.''5 slit width and 1 × 1 CCD pixel binning (corresponding to ∼2.5 Å spectral resolution) and the other with 0.''75 slit width and 2 × 2 binning (∼4 Å). We find small and well-defined correction terms for the set of Balmer indices Hβ, Hγ {sub A}, and Hδ {sub A} along with the metallicity sensitive indices Fe5015, Fe5270, Fe5335, Fe5406, Mg{sub 2}, and Mgb that are widely used for stellar population diagnostics of distant stellar systems. We find other indices that sample molecular absorption bands, such as TiO{sub 1} and TiO{sub 2}, with very wide wavelength coverage or indices that sample very weak molecular and atomic absorption features, such as Mg{sub 1}, as well as indices with particularly narrow passband definitions, such as Fe4384, Ca4455, Fe4531, Ca4227, and Fe5782, which are less robustly calibrated. These indices should be used with caution.

  19. Gemini/GMOS photometry of intermediate-age star clusters in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Piatti, Andrés E.; Keller, Stefan C.; Mackey, A. Dougal; Da Costa, Gary S.

    2014-10-01

    We present Gemini South GMOS g, i photometry of 14 intermediate-age Large Magellanic Cloud (LMC) star clusters, namely: NGC 2155, 2161, 2162, 2173, 2203, 2209, 2213, 2231, 2249, Hodge 6, SL 244, 505, 674, and 769, as part of a continuing project to investigate the extended main-sequence turn-off (EMSTO) phenomenon. Extensive artificial star tests were made over the observed field of view. These tests reveal the observed behaviour of photometric errors with magnitude and crowding. The cluster stellar density radial profiles were traced from star counts over the extent of the observed field. We adopt cluster radii and build colour-magnitude diagrams (CMDs) with cluster features clearly identified. We used the cluster (g, g - i) CMDs to estimate ages from the matching of theoretical isochrones. The studied LMC clusters are confirmed to be intermediate-age clusters, which range in age 9.10 < log(t) < 9.60. NGC 2162 and NGC 2249 look like new EMSTO candidates, in addition to NGC 2209, on the basis of having dual red clumps.

  20. The Gemini Science User Support Department: A community-centered approach to user support

    NASA Astrophysics Data System (ADS)

    Chené, André-Nicolas; Thomas-Osip, Joanna

    2016-01-01

    The Gemini Science User Support Department (SUSD) was formed a little more than a year ago to create a collaborative community of users and staff and to consolidate existing post-observing support throughout the observatory for more efficient use of resources as well as better visibility amongst our user community. This poster is an opportunity to exchange ideas about how Gemini can improve your experience while working with the Observatory and present details about new avenues of post-observing support coming soon. We encourage your feedback at any time.Shortly after its creation, the SUSD conducted a complete revision of the communication cycle between Gemini and its community of researchers. The cycle was then revisited from the perspective of an astronomer interested in using Gemini for their research. This exercise led to a series of proposed changes that are currently under development, and the implementation of a sub-selection is expected in 2016, including the following. (1) Email notifications: Gemini users will receive new forms of email communications that are more instructive and tailored to their program. The objective is to direct the users more efficiently toward the useful links and documentation all along the lifecycle of the program, from phaseII to after the data are completely reduced. (2) HelpDesk system: The HelpDesk will become more user-friendly and transparent. (3) Webpages: The organization of the Gemini webpages will be redesigned to optimize navigation; especially for anything regarding more critical periods likes phaseIs and phaseIIs. (4) Data Reduction User Forum: Following recommendations from Gemini users, new capabilities were added to the forum, like email notifications, and a voting system, in order to make it more practical. This forum's objective is to bring the Gemini community together to exchange their ideas, thoughts, questions and solutions about data reduction, a sort of Reddit, StackOverflow or Slashdot for Gemini data.

  1. Upgrade and standardization of real-time software for telescope systems at the Gemini telescopes

    NASA Astrophysics Data System (ADS)

    Rambold, William N.; Gigoux, Pedro; Urrutia, Cristian; Ebbers, Angelic; Taylor, Philip; Rippa, Mathew J.; Rojas, Roberto; Cumming, Tom

    2014-07-01

    The real-time control systems for the Gemini Telescopes were designed and built in the 1990s using state-of-the-art software tools and operating systems of that time. Since these systems are in use every night they have not been kept upto- date and are now obsolete and very labor intensive to support. Gemini is currently engaged in a major upgrade of its telescope control systems. This paper reviews the studies performed to select and develop a new standard operating environment for Gemini real-time systems and the work performed so far in implementing it.

  2. Ceremonies for Gemini 10 crew on the U.S.S. Guadalcanal

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Twelve-year-old Bill Doyle of Virginia Beach, VA., shakes hands with Gemini 10 pilot Michael Collins aboard the recovery ship U.S.S. Guadalcanal. At right is John W. Young, Gemini 10 command pilot. Billy represented 41 youngsters permitted aboard the Guadalcanal to witness the recovery with their Naval fathers or close relatives, marking the first time dependents have been permitted aboard a ship during a Gemini recovery operation. In front of them is a large cake baked by the ship's cooks for the occasion.

  3. Experiment T001: Entry communication on the Gemini 3 mission

    NASA Technical Reports Server (NTRS)

    Schroeder, L. C.; Sims, T. E.; Cuddihy, W. F.

    1971-01-01

    Water addition to the Gemini 3 exhaust plasma was studied to determine its effectiveness in the establishment of communication links during the entry portion of the flight. Attenuation levels were measured with and without water injection at uhf frequencies of 230.4 and 296.8 megahertz and at the C-band frequency of 5690 megahertz. Ultrahigh frequency signals that had been blacked out were restored to significant levels, during early portions of the water-injection sequence, by the high flow rate injection. The C-band signal was enhanced by medium and high flow rate injections during the latter portion of the injection period. The uhf signal recovered during water injection resulted in an antenna pattern that was beamed in the radial direction of injection from the spacecraft. Postflight analysis showed that the uhf recovery data were consistent with injection-penetration theory.

  4. Fan-In Communications On A Cray Gemini Interconnect

    SciTech Connect

    Jones, Terry R; Settlemyer, Bradley W

    2014-01-01

    Using the Cray Gemini interconnect as our platform, we present a study of an important class of communication operations the fan-in communication pattern. By its nature, fan-in communications form hot spots that present significant challenges for any interconnect fabric and communication software stack. Yet despite the inherent challenges, these communication patterns are common in both applications (which often perform reductions and other collective operations that include fan-in communication such as barriers) and system software (where they assume an important role within parallel file systems and other components requiring high-bandwidth or low-latency I/O). Our study determines the effectiveness of differing clientserver fan-in strategies. We describe fan-in performance in terms of aggregate bandwidth in the presence of varying degrees of congestion, as well as several other key attributes. Comparison numbers are presented for the Cray Aries interconnect. Finally, we provide recommended communication strategies based on our findings.

  5. The synthesis and properties of a new nonionic Gemini surfactant

    NASA Astrophysics Data System (ADS)

    Ren, Yanmei; Lv, Tong; Wang, Qi; Tian, Zhenxing

    2010-07-01

    A new Gemini nonionic surfactant was prepared, taking anhydrous glucose, glycol, maleic anhydride, lauric acid as main materials, and the reaction was carried out by three steps. Firstly, glycol glucoside was synthesized by the direct glycosidation of the anhydrous glucose with glycol in the presence of acidic catalyst. The synthesis and the characterization of this have been reported previously.Secondly, reaction intermediate was prepared by ring opening reaction of maleic anhydride with glycol glucoside. The last, primary hydroxyl group in glucose of reaction intermediate was esterified with lauric acid for synthesis of target product. It was analyzed and characterized by IR, 1HNMR and 13CNMR. Besides, the critical micelle concentration (cmc) and the corresponding surface tension of the target product were measured to be 8.87×10-3molL-1 and 20.70mNm-1 (20°C), respectively.

  6. Gemini ester quat surfactants and their biological activity.

    PubMed

    Łuczyński, Jacek; Frąckowiak, Renata; Włoch, Aleksandra; Kleszczyńska, Halina; Witek, Stanisław

    2013-03-01

    Cationic gemini surfactants are an important class of surface-active compounds that exhibit much higher surface activity than their monomeric counterparts. This type of compound architecture lends itself to the compound being easily adsorbed at interfaces and interacting with the cellular membranes of microorganisms. Conventional cationic surfactants have high chemical stability but poor chemical and biological degradability. One of the main approaches to the design of readily biodegradable and environmentally friendly surfactants involves inserting a bond with limited stability into the surfactant molecule to give a cleavable surfactant. The best-known example of such a compound is the family of ester quats, which are cationic surfactants with a labile ester bond inserted into the molecule. As part of this study, a series of gemini ester quat surfactants were synthesized and assayed for their biological activity. Their hemolytic activity and changes in the fluidity and packing order of the lipid polar heads were used as the measures of their biological activity. A clear correlation between the hemolytic activity of the tested compounds and their alkyl chain length was established. It was found that the compounds with a long hydrocarbon chain showed higher activity. Moreover, the compounds with greater spacing between their alkyl chains were more active. This proves that they incorporate more easily into the lipid bilayer of the erythrocyte membrane and affect its properties to a greater extent. A better understanding of the process of cell lysis by surfactants and of their biological activity may assist in developing surfactants with enhanced selectivity and in widening their range of application.

  7. Monolayer behavior of asymmetrical ester-type tartaric gemini amphiphiles.

    PubMed

    Kawase, Tokuzo; Saito, Isao; Oida, Tatsuo

    2013-01-01

    The ester-type asymmetrical tartaric gemini amphiphiles (C(m)-C(n), where m and n are the number of carbon atoms of hydrophobic alkanoyl group, m+n=28) bearing two carboxyl groups and two different alkanoyl groups were prepared from L-tartaric acid, and the pressure-area (π-A) isotherms for a series of asymmetrical tartaric gemini amphiphiles were studied.The π-A isotherms of asymmetrical C(m)-C(n) monolayers were classified into two groups. Group 1: The asymmetry was small (n/m <1.55), and a phase transition of the monolayer from the liquid-expanded to the liquid condensed state, and a subsequent transition to solid phases were observed. Group 2: The asymmetry was large (n/m >1.8), and only liquid-expanded state of the monolayer film was observed. Based on the subphase temperature (T(sub)) dependence of monolayer static elasticity, es, the melting temperature (T(L)) of asymmetrical C(m)-C(n) monolayer was estimated to be T(L) = 31.7°C and 50.6°C for C₁₃-C₁₅ and C₁₂-C₁₆, respectively. Furthermore, assuming that asymmetrical C₁₃-C₁₅ can be viewed as an equimolar mixture of symmetrical 2C₁₃ and 2C₁₅, the temperature dependence of monolayers of 2C₁₃ and 2C₁₅ mixture at various ratios were also studied. As a result, all TL values of 2C14, C₁₃-C₁₅ and an equimolar mixture of 2C₁₃ and 2C₁₅ were almost the same. However, the variation of T(L) with the molar fraction of 2C₁₅ (X(2C15)) was remarkably different from that of solid melting point T(m) with X(2C15).

  8. Gemini 12 crew receive Official welcome aboard U.S.S. Wasp

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Astronauts James A. Lovell Jr. (left), command pilot, and Edwin E. Aldrin Jr., pilot, receive Official welcome as they arrive aboard the aircraft carrier U.S.S. Wasp after their splashdown at the end of the Gemini 12 mission.

  9. Synthesis and crystal structures of gold nanowires with Gemini surfactants as directing agents.

    PubMed

    Xu, Feng; Hou, Hao; Gao, Zhinong

    2014-12-15

    The preparation of crystalline gold nanowires (NWs) by using gemini surfactants as directing agents through a three-step seed-mediated method is reported. Unlike the nanorods with relatively low aspect ratios (typically below 20) obtained by using cetyltrimethylammonium bromide as a directing agent, the NWs obtained in this investigation can reach up to 4.4 μm, and the largest aspect ratio is calculated to be 210. For this, each of seven different gemini surfactants are utilized as directing agents, and the length and/or aspect ratio of the NWs can be tuned by varying the hydrocarbon chain lengths of the gemini surfactants. Both single and twinned crystalline structures are elucidated by selected-area electron diffraction and high-resolution transmission electron microscopy studies. The use of gemini surfactants not only advances the synthesis of gold nanostructures, but improves the understanding of the growth mechanism for seed-mediated growth.

  10. Hydrodynamic size of DNA/cationic gemini surfactant complex as a function of surfactant structure.

    PubMed

    Devínsky, Ferdinand; Pisárcik, Martin; Lacko, Ivan

    2009-06-01

    The present study deals with the determination of hydrodynamic size of DNA/cationic gemini surfactant complex in sodium bromide solution using the dynamic light scattering method. Cationic gemini surfactants with polymethylene spacer of variable length were used for the interaction with DNA. The scattering experiments were performed at constant DNA and sodium bromide concentrations and variable surfactant concentration in the premicellar and micellar regions as a function of surfactant spacer length. It was found that the DNA conformation strongly depends on the polymethylene spacer length as well as on the surfactant concentration relative to the surfactant critical micelle concentration. Gemini surfactant molecules with 4 methylene groups in the spacer were found to be the least efficient DNA compacting agent in the region above the surfactant cmc. Gemini molecules with the shortest spacer length (2 methylene groups) and the longest spacer length (8 methylene groups) investigated showed the most efficient DNA compaction ability. PMID:19592712

  11. Synthesis and crystal structures of gold nanowires with Gemini surfactants as directing agents.

    PubMed

    Xu, Feng; Hou, Hao; Gao, Zhinong

    2014-12-15

    The preparation of crystalline gold nanowires (NWs) by using gemini surfactants as directing agents through a three-step seed-mediated method is reported. Unlike the nanorods with relatively low aspect ratios (typically below 20) obtained by using cetyltrimethylammonium bromide as a directing agent, the NWs obtained in this investigation can reach up to 4.4 μm, and the largest aspect ratio is calculated to be 210. For this, each of seven different gemini surfactants are utilized as directing agents, and the length and/or aspect ratio of the NWs can be tuned by varying the hydrocarbon chain lengths of the gemini surfactants. Both single and twinned crystalline structures are elucidated by selected-area electron diffraction and high-resolution transmission electron microscopy studies. The use of gemini surfactants not only advances the synthesis of gold nanostructures, but improves the understanding of the growth mechanism for seed-mediated growth. PMID:25257473

  12. Target of Opportunity Observing in Queue Mode at the Gemini North Observatory

    NASA Astrophysics Data System (ADS)

    Roth, Katherine; Price, P.; Gillies, K.; Walker, S.; Miller, B.

    2009-01-01

    The Gemini Observatories primarily operate a multi-instrument queue, with observers selecting observations that are best suited to weather and seeing conditions. Queue operations give higher ranked programs a greater chance for completion than lower ranked programs requesting the same conditions and instrument configuration. Queue observing naturally lends itself to Target of Opportunity (ToO) support since the time required to switch between programs and instruments is very short, and the staff observer is trained to operate all the available instruments and modes. Gemini Observatory has supported pre-approved ToO programs since beginning queue operations, and has implemented a rapid (less than 15 minutes response time) ToO mode since 2005. The rapid response ToO mode has thus far been exclusively utilized by the Gemini community for optical and near-IR follow-up of Gamma Ray Bursts (GRBs), primarily discovered by the Swift satellite. We discuss the ToO implementation at Gemini Observatory including the ToO user interface and the procedures followed by observatory staff astronomers once a ToO trigger is received. We present the statistics of 4 years of rapid ToOs at Gemini North Observatory, and the advances in our understanding of GRBs, their host galaxies and the intergalactic medium that this important mode has enabled. Finally we discuss recent changes in both software and policy to improve standard and rapid ToO support at the Gemini Observatories. The Gemini Observatory is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciìncia e Tecnologia (Brazil), and SECYT (Argentina)

  13. Hierarchical Structure from the Self-Assembly of Giant Gemini Surfactants in Condensed State

    NASA Astrophysics Data System (ADS)

    Su, Hao; Wang, Zhao; Li, Yiwen; Cheng, Stephen

    2013-03-01

    In the past a few years, a new class of amphiphiles with both asymmetrical shapes and interactions named ``shape amphiphiles'' has been significantly intensified. Recently, a new kind of shape amphiphiles called ``Giant Gemini Surfactants'' consisting of two hydrophilic carboxylic acid-functionalized polyhedral oligomeric silsesquioxane (APOSS) heads and two hydrophobic polystyrene (PS) tails covalently linked via rigid spacers (p-phenylene versus biphenylene) has been successful behavior of giant gemini surfactants. We currently continue to investigate the spacer effects on the self-assembly behaviors of giant gemini surfactants in condensed state by utilizing DCS, SAXS and TEM. Preliminary results showed that giant gemini surfactants with different spacers have diverse phase behaviors. As we use the same 3.2k PS chains, the giant gemini surfactant with p-phenylene spacer showed double gyroid morphology, while the one with biphenylene spacer revealed cylindrical morphology. This study expands the scope of giant gemini surfactants and contributes a lot to the basic physical principles in self-assembly behavior.

  14. 8-mJ TEM(00) diode-end-pumped frequency-quadrupled Nd:YAG laser.

    PubMed

    Feugnet, G; Pocholle, J P

    1998-01-01

    A frequency-quadrupled Nd:YAG laser pumped by a commercially available high-brightness stack is described. A master oscillator power amplifier configuration was implanted, and the laser delivered energy of 8 mJ at 0.266microm . The laser was air cooled for easy use.

  15. The Gemini NICI Planet-Finding Campaign: The Offset Ring of HR 4796 A

    NASA Technical Reports Server (NTRS)

    Wahhaj, Zahed; Liu, Michael C.; Biller, Beth A.; Nielsen, Eric L.; Hayward, Thomas L.; Kuchner, Marc J.; Close, Laird M.; Chun, Mark; Ftaclas, Christ; Toomey, Douglas W.

    2014-01-01

    We present J, H, CH4 short (1.578 micrometers), CH4 long (1.652 micrometers) and K(sub s)-band images of the dust ring around the 10 Myr old star HR 4796 A obtained using the Near Infrared Coronagraphic Imager (NICI) on the Gemini-South 8.1 m Telescope. Our images clearly show for the first time the position of the star relative to its circumstellar ring thanks to NICI's translucent focal plane occulting mask. We employ a Bayesian Markov chain Monte Carlo method to constrain the offset vector between the two. The resulting probability distribution shows that the ring center is offset from the star by 16.7 +/- 1.3 milliarcseconds along a position angle of 26 +/- 3deg, along the PA of the ring, 26.47 +/- 0.04deg. We find that the size of this offset is not large enough to explain the brightness asymmetry of the ring. The ring is measured to have mostly red reflectivity across the JHKs filters, which seems to indicate micron-sized grains. Just like Neptune's 3:2 and 2:1 mean-motion resonances delineate the inner and outer edges of the classical Kuiper belt, we find that the radial extent of the HR 4796 A and the Fomalhaut rings could correspond to the 3:2 and 2:1 mean-motion resonances of hypothetical planets at 54.7 AU and 97.7 AU in the two systems, respectively. A planet orbiting HR 4796 A at 54.7 AU would have to be less massive than 1.6 Jup mass so as not to widen the ring too much by stirring.

  16. Design and analysis of the Gemini chain system in dual clutch transmission of automobile

    NASA Astrophysics Data System (ADS)

    Cheng, Yabing; Guo, Haitao; Fu, Zhenming; Wan, Nen; Li, Lei; Wang, Yang

    2015-01-01

    Chain drive system is widely used in the conditions of high-speed, overload, variable speed and load. Many studies are focused on the meshing theory and wear characteristics of chain drive system, but system design, analysis, and noise characteristics of the chain drive system are weak. System design and noise characteristic are studied for a new type Gemini chain of dual-clutch automatic transmission. Based on the meshing theory of silent chain, the design parameters of the Gemini chain system are calculated and the mathematical models and dynamic analysis models of the Gemini chain system are established. Dynamic characteristics of the Gemini chain system is simulated and the contact force of plate and pin, plate and sprockets, the chain tension forces, the transmission error and the stress of plates and pins are analyzed. According to the simulation results of the Gemini chain system, the noise experiment about system is carried out. The noise values are tested at different speed and load and spectral characteristics are analyzed. The results of simulation and experimental show that the contact forces of plate and pin, plate and sprockets are smaller than the allowable stress values, the chain tension force is less than ultimate tension and transmission error is limited in 1.2%. The noise values can meet the requirements of industrial design, and it is proved that the design and analysis method of the Gemini chain system is scientific and feasible. The design and test system is built from analysis to test of Gemini chain system. This research presented will provide a corresponding theoretical guidance for the design and dynamic characteristics and noise characteristics of chain drive system.

  17. The Gemini Planet Imager Exoplanet Survey (GPIES) Campaign Initial Results

    NASA Astrophysics Data System (ADS)

    Patience, Jennifer; Macintosh, Bruce; Graham, James R.; Barman, Travis; De Rosa, Robert; Konopacky, Quinn; Marley, Mark; Marois, Christian; Nielsen, Eric Ludwig; Pueyo, Laurent; Rajan, Abhijith; Rameau, Julien; Saumon, Didier; Wang, Jason

    2015-12-01

    The Gemini Planet Imager (GPI) is a next-generation coronagraphic integral field unit with the sensitivity and resolution to detect planetary companions with separations of 0”.2 to 1”.0 around a large set of stars. An 890-hour GPI survey of 600 young, nearby stars commenced in late-2014, and approximately 100 stars have been observed thus far. The central aims of the program are: (1) the discovery of a population of giant planets with orbital radii of 5-50 AU comparable to Solar System gas giant orbits, (2) the characterization of the atmospheric properties of young planetary companions, and (3) the exploration of planet-disk interactions. Initial results from GPI exoplanet observations include the discovery of a new planetary companion to a young F-star; the planet spectrum shows a strong signature of methane absorption, indicating a cooler temperature than previously imaged young planets. An overview of the survey scope, current detection limits, and initial results will be presented.

  18. Synthesis and Monolayer Behaviors of Succinic Acid-Type Gemini Surfactants Containing Semifluoroalkyl Groups.

    PubMed

    Kawase, Tokuzo; Nagase, Youhei; Oida, Tatsuo

    2016-01-01

    In this work, novel succinic acid-type gemini surfactants containing semifluoroalkyl groups, dl- and meso-2,3-bis[Rf-(CH2)n]-succinic acids (Rf = C4F9, C6F13, C8F17; n = 2, 9), were successfully synthesized, and the effects of Rf, methylene chain length (n), and stereochemistry on their monolayer behaviors were studied. Critical micelle concentrations (CMC) of dl- and meso-2,3-bis[C4F9(CH2)9]-succinic acids were one order of magnitude smaller than that of the corresponding 1+1 type surfactant, C4F9(CH2)9COOH. From surface pressure-area (π-A) measurements, the lift-off areas of the geminis were found to decrease in the order C4F9 ≥ C6F13 > C8F17, regardless of methylene chain length and stereochemistry. The zero-pressure molecular areas of the geminis were twice those of the corresponding 1+1 type surfactants. Based on Gibbs compression modulus analysis, it was clarified that 2,3-bis[C8F17(CH2)n]-succinic gemini with short methylene chains (n = 2) would form more rigid monolayers than those having long methylene chains (n = 9). Unlike for 2,3-bis(alkyl)-succinic acids, the effects of stereochemistry on the monolayer behavior of semifluoroalkylated geminis were small.

  19. Antibacterial Activity, in Vitro Cytotoxicity, and Cell Cycle Arrest of Gemini Quaternary Ammonium Surfactants.

    PubMed

    Zhang, Shanshan; Ding, Shiping; Yu, Jing; Chen, Xuerui; Lei, Qunfang; Fang, Wenjun

    2015-11-10

    Twelve gemini quaternary ammonium surfactants have been employed to evaluate the antibacterial activity and in vitro cytotoxicity. The antibacterial effects of the gemini surfactants are performed on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) with minimum inhibitory concentrations (MIC) ranging from 2.8 to 167.7 μM. Scanning electron microscopy (SEM) analysis results show that these surfactants interact with the bacterial cell membrane, disrupt the integrity of the membrane, and consequently kill the bacteria. The data recorded on C6 glioma and HEK293 human kidney cell lines using an MTT assay exhibit low half inhibitory concentrations (IC50). The influences of the gemini surfactants on the cell morphology, the cell migration ability, and the cell cycle are observed through hematoxylin-eosin (HE) staining, cell wound healing assay, and flow cytometric analyses, respectively. Both the values of MIC and IC50 decrease against the growth of the alkyl chain length of the gemini surfactants with the same spacer group. In the case of surfactants 12-s-12, the MICs and IC50s are found to decrease slightly with the spacer chain length changing from 2 to 8 and again to increase at higher spacer length (s = 10-12). All of the gemini surfactants show great antibacterial activity and cytotoxicity, and they might exhibit potential applications in medical fields.

  20. Synthesis and Monolayer Behaviors of Succinic Acid-Type Gemini Surfactants Containing Semifluoroalkyl Groups.

    PubMed

    Kawase, Tokuzo; Nagase, Youhei; Oida, Tatsuo

    2016-01-01

    In this work, novel succinic acid-type gemini surfactants containing semifluoroalkyl groups, dl- and meso-2,3-bis[Rf-(CH2)n]-succinic acids (Rf = C4F9, C6F13, C8F17; n = 2, 9), were successfully synthesized, and the effects of Rf, methylene chain length (n), and stereochemistry on their monolayer behaviors were studied. Critical micelle concentrations (CMC) of dl- and meso-2,3-bis[C4F9(CH2)9]-succinic acids were one order of magnitude smaller than that of the corresponding 1+1 type surfactant, C4F9(CH2)9COOH. From surface pressure-area (π-A) measurements, the lift-off areas of the geminis were found to decrease in the order C4F9 ≥ C6F13 > C8F17, regardless of methylene chain length and stereochemistry. The zero-pressure molecular areas of the geminis were twice those of the corresponding 1+1 type surfactants. Based on Gibbs compression modulus analysis, it was clarified that 2,3-bis[C8F17(CH2)n]-succinic gemini with short methylene chains (n = 2) would form more rigid monolayers than those having long methylene chains (n = 9). Unlike for 2,3-bis(alkyl)-succinic acids, the effects of stereochemistry on the monolayer behavior of semifluoroalkylated geminis were small. PMID:26743669

  1. The Gemini/NICI Planet-Finding Campaign: The Frequency of Planets around Young Moving Group Stars

    NASA Astrophysics Data System (ADS)

    Biller, Beth A.; Liu, Michael C.; Wahhaj, Zahed; Nielsen, Eric L.; Hayward, Thomas L.; Males, Jared R.; Skemer, Andrew; Close, Laird M.; Chun, Mark; Ftaclas, Christ; Clarke, Fraser; Thatte, Niranjan; Shkolnik, Evgenya L.; Reid, I. Neill; Hartung, Markus; Boss, Alan; Lin, Douglas; Alencar, Silvia H. P.; de Gouveia Dal Pino, Elisabete; Gregorio-Hetem, Jane; Toomey, Douglas

    2013-11-01

    We report results of a direct imaging survey for giant planets around 80 members of the β Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini/NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of ΔH = 13.9 mag at 1'' in combined CH4 narrowband ADI+SDI mode and median contrasts of ΔH = 15.1 mag at 2'' in H-band ADI mode. We found numerous (>70) candidate companions in our survey images. Some of these candidates were rejected as common-proper motion companions using archival data; we reobserved with Near-Infrared Coronagraphic Imager (NICI) all other candidates that lay within 400 AU of the star and were not in dense stellar fields. The vast majority of candidate companions were confirmed as background objects from archival observations and/or dedicated NICI Campaign followup. Four co-moving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36 ± 6 M Jup, 16.4 ± 1.0 AU), CD-35 2722B (31 ± 8 M Jup, 67 ± 4 AU), HD 12894B (0.46 ± 0.08 M ⊙, 15.7 ± 1.0 AU), and BD+07 1919C (0.20 ± 0.03 M ⊙, 12.5 ± 1.4 AU). From a Bayesian analysis of the achieved H band ADI and ASDI contrasts, using power-law models of planet distributions and hot-start evolutionary models, we restrict the frequency of 1-20 M Jup companions at semi-major axes from 10-150 AU to <18% at a 95.4% confidence level using DUSTY models and to <6% at a 95.4% using COND models. Our results strongly constrain the frequency of planets within semi-major axes of 50 AU as well. We restrict the frequency of 1-20 M Jup companions at semi-major axes from 10-50 AU to <21% at a 95.4% confidence level using DUSTY models and to <7% at a 95.4% using COND models. This survey is the deepest search to date for giant planets around young moving group stars. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc

  2. Solution Properties of Dissymmetric Sulfonate-type Anionic Gemini Surfactants.

    PubMed

    Yoshimura, Tomokazu; Akiba, Kazuki

    2016-01-01

    Dissymmetric and symmetric anionic gemini surfactants, N-alkyl-N'-alkyl-N,N'dipropanesulfonylethylenediamine (CmCnSul, where m and n represent alkyl chain lengths of m-n = 4-16, 6-14, 8-12, 10-10, and 12-12), were synthesized by two- or three-step reactions. Their physicochemical properties were characterized by equilibrium surface tension measurements, steady-state fluorescence spectroscopy of pyrene, and dynamic light scattering. The critical micelle concentration (CMC) of the dissymmetric surfactants C4C16Sul, C6C14Sul, and C8C12Sul was slightly lower than that of the symmetric surfactant C10C10Sul. The occupied area per molecule (A) of C8C12Sul was smaller than that of C10C10Sul, indicating that C8C12Sul has a high surface activity. However, the increase in the degree of dissymmetry from C8C12Sul to C6C14Sul and then to C4C16Sul resulted in high surface tension and large A. Based on the surface tension, the standard free energies of micellization (∆G°mic) and adsorption (∆G°ads), the efficiency of surface adsorption (pC20), and the effectiveness of surface adsorption (CMC/C20) were obtained. These parameters suggested that C8C12Sul formed micelles more readily than the other surfactants. The properties determined from the surface tension indicated that C8C12Sul's ability is intermediate between those of C10C10Sul and C12C12Sul. The pyrene fluorescence and dynamic light scattering results revealed that the micelle size depends on the longer of the two alkyl chains in dissymmetric surfactants.

  3. Thermodynamic investigation of the binding of dissymmetric pyrenyl-gemini surfactants to DNA.

    PubMed

    Wettig, Shawn D; Deubry, Rubena; Akbar, Javed; Kaur, Tranum; Wang, Haitang; Sheinin, Tatiana; Joseph, Jamie W; Slavcev, Roderick A

    2010-05-14

    Gemini surfactants have demonstrated significant potential for use in constructing non-viral transfection vectors for the delivery of genes into cells to induce protein expression. Previously, two asymmetric gemini surfactants containing pyrenyl groups in one of the alkyl tails of the surfactants were synthesized as fluorescence probes for use in mechanistic studies of the transfection process. Here we present the results of a thermodynamic investigation of the binding interaction(s) between the pyrenyl-modified surfactants and DNA. The thermodynamics of the interactions have been examined using isothermal titration calorimetry, light scattering, zeta potential, and circular dichroism measurements. Distinct differences are observed between the interaction of 12-s-12 vs. the pyrene modified py-s-12 surfactants with DNA; an intercalated binding is found for the py-s-12 surfactants that disrupts the typical interactions observed between DNA and gemini surfactants.

  4. A comparison of Gemini and ERTS imagery obtained over southern Morocco

    NASA Technical Reports Server (NTRS)

    Blodget, H. W.; Anderson, A. T.

    1973-01-01

    A mosaic constructed from three ERTS MSS band 5 images enlarged to 1:500,000 compares favorably with a similar scale geologic map of southern Morocco, and a near-similar scale Gemini 5 photo pair. A comparative plot of lineations and generalized geology on the three formats show that a significantly greater number of probable fractures are visible on the ERTS imagery than on the Gemini photography, and that both orbital formats show several times more lineaments than were previously mapped. A plot of mineral occurrences on the structural overlays indicates that definite structure-mineralization relationships exist; this finding is used to define underdeveloped areas which are prospective for mineralization. More detailed mapping is possible using MSS imagery than on Gemini 5 photographs, and in addition, the ERTS format is not restricted to limited coverage.

  5. A new look for Gemini: rapid-cured composites for an exchangeable top-end

    NASA Astrophysics Data System (ADS)

    Miziarski, Stan; McGrath, Andrew; Milby, N.; Brosius, D. E.; von Bertouch, M. J.

    2006-06-01

    The Gemini-sponsored WFMOS Feasibility Study investigated a wide-field, prime focus installation for the Gemini telescopes. As constructed, the Gemini design allows for multiple, interchangeable telescope top-ends, although this capability has never been implemented. Constrained by a particularly challenging top-end mass budget, we proposed a new top end specific to WFMOS, employing a carbon fiber reinforced plastic structure. An innovative, out-of-autoclave manufacturing process using balanced pressure and liquid heating and cooling enables high-specification, large CFRP structures to be constructed suitable for incorporation as fundamental parts of telescope structures. Advantages include low weight, enhanced overall telescope stiffness, and cost-effective construction with on-site final assembly. We describe the manufacturing process and the proposed top-end structure, as well as highlighting the advantages of this type of structure and material for large and extremely large telescopes in general.

  6. Structural and transfection properties of amine-substituted gemini surfactant-based nanoparticles

    SciTech Connect

    Wettig,S.; Badea, I.; Donkuru, M.; Verrall, R.; Foldvari, M.

    2007-01-01

    Increases in DNA transfection efficiencies for non-viral vectors can be achieved through rational design of novel cationic building blocks. Based on previous results examining DNA condensation by polyamines, novel gemini surfactants have been designed that incorporate aza or imino substituents within the spacer group in order to increase interactions with DNA and potentially improve their DNA transfection ability. Transfection efficiencies and cell toxicity of gemini nanoparticles constructed from plasmid DNA, gemini surfactant, and a neutral lipid were measured in COS7 cells using a luciferase assay. Structural properties of nanoparticles were examined by using circular dichroism, particle size, zeta potential, and small-angle X-ray scattering (SAXS) measurements. The incorporation of aza and imino substituents within the spacer group was observed to enhance the transfection ability of gemini surfactants. Incorporation of an imino group in the structure of the 1,9-bis(dodecyl)-1,1,9,9-tetramethyl-5-imino-1,9-nonanediammonium dibromide surfactant (12-7NH-12) resulted in a statistically significant (p < 0.01) 9-fold increase in transfection compared to an unsubstituted gemini surfactant and a 3-fold increase compared to the corresponding aza-substituted compound. A pH-dependent transition in size and zeta potential was observed to occur at pH 5.5 for complexes formed from the 12-7NH-12 compound. SAXS results show weakly ordered structures and the presence of multiple phases. The incorporation of a pH-active imino group within the spacer of the gemini surfactant results in a significant increase in transfection efficiency that can be related to both pH-induced changes in nanoparticle structure and the formation of multiple phases that more readily allow for membrane fusion that may facilitate DNA release.

  7. Modern Gemini-Approach to Technology Development for Human Space Exploration

    NASA Technical Reports Server (NTRS)

    White, Harold

    2010-01-01

    In NASA's plan to put men on the moon, there were three sequential programs: Mercury, Gemini, and Apollo. The Gemini program was used to develop and integrate the technologies that would be necessary for the Apollo program to successfully put men on the moon. We would like to present an analogous modern approach that leverages legacy ISS hardware designs, and integrates developing new technologies into a flexible architecture This new architecture is scalable, sustainable, and can be used to establish human exploration infrastructure beyond low earth orbit and into deep space.

  8. Deep-depletion Hamamatsu CCDs for the Gemini multi-object spectrograph

    NASA Astrophysics Data System (ADS)

    Hardy, Tim; Hanna, Kevin; Szeto, Kei; Burley, Greg

    2012-07-01

    The instrumentation group of the Herzberg Institute of Astrophysics was commissioned by the Gemini Observatory to develop a new focal plane assembly for the Gemini Multi-Object Spectrograph with an array of three deep-depletion Hamamatsu CCDs. The main objective of the upgrade is to improve the sensitivity of the instrument in the red and nearinfrared wavelengths, with the additional benefits of reduced fringing, faster readout, and better performance in the "nod and shuffle" mode. We describe what we learned about these relatively new CCDs, including several problems encountered during testing, and report on the performance of the system.

  9. An ultra short pulse reconstruction software applied to the GEMINI high power laser system

    NASA Astrophysics Data System (ADS)

    Galletti, Mario; Galimberti, Marco; Hooker, Chris; Chekhlov, Oleg; Tang, Yunxin; Bisesto, Fabrizio Giuseppe; Curcio, Alessandro; Anania, Maria Pia; Giulietti, Danilo

    2016-09-01

    The GRENOUILLE traces of Gemini pulses (15 J, 30 fs, PW, shot per 20 s) were acquired in the Gemini Target Area PetaWatt at the Central Laser Facility (CLF), Rutherford Appleton Laboratory (RAL). A comparison between the characterizations of the laser pulse parameters made using two different types of algorithms: Video Frog and GRenouille/FrOG (GROG), was made. The temporal and spectral parameters came out to be in great agreement for the two kinds of algorithms. In this experimental campaign it has been showed how GROG, the developed algorithm, works as well as VideoFrog algorithm with the PetaWatt pulse class.

  10. Weldability of corrosion-resistant high-nitrogen austenitic Kh22AG16N8M-type steels

    NASA Astrophysics Data System (ADS)

    Bannykh, O. A.; Blinov, V. M.; Kostina, M. V.; Blinov, E. V.; Zvereva, T. N.

    2007-10-01

    The influence of thermal treatment on the structures and mechanical properties of welds of corrosion-resistant high-nitrogen austenitic 05Kh22AG16N8M-type steels is studied. In these steels, austenite is found to be highly resistant to discontinuous precipitation and the formation of σ phase and δ ferrite upon cooling regardless of the temperature of heating for quenching (from 900 to 1250°C) and the cooling conditions (water, air, furnace). Welding of these steels can produce high-strength welds with an enhanced impact toughness.

  11. Machining of Christmas tree parts of 06Kh20N8M3D2L corrosion-resistant steel

    SciTech Connect

    Rubinov, S.R.; Balaoglanov, M.M.; Baluyants, E.G.

    1983-09-01

    To address the problem of corrosion cracking, equipment has been developed of 06Kh20N8M3D21 austenitic-ferritic corrosion-resistant multiply alloyed steel. But as this steel is difficult to machine investigations were made to determine the parameters and conditions for machining Christmas tree parts made of this steel. Turning, drilling, thread cutting, and milling are specified. The optimum conditions for machining Christmas tree parts were established in tests. The tests also showed that the coefficient of machinability of the steel is 3 or 4 times less than that of 20KhGSL steel, which is normally used for Christmas tree production.

  12. [Cr(III)8M(II)6](12+) Coordination Cubes (M(II)=Cu, Co).

    PubMed

    Sanz, Sergio; O'Connor, Helen M; Pineda, Eufemio Moreno; Pedersen, Kasper S; Nichol, Gary S; Mønsted, Ole; Weihe, Høgni; Piligkos, Stergios; McInnes, Eric J L; Lusby, Paul J; Brechin, Euan K

    2015-06-01

    [Cr(III)8M(II)6](12+) (M(II) =Cu, Co) coordination cubes were constructed from a simple [Cr(III) L3 ] metalloligand and a "naked" M(II) salt. The flexibility in the design proffers the potential to tune the physical properties, as all the constituent parts of the cage can be changed without structural alteration. Computational techniques (known in theoretical nuclear physics as statistical spectroscopy) in tandem with EPR spectroscopy are used to interpret the magnetic behavior.

  13. The Gemini/NICI Planet-Finding Campaign: The Frequency of Planets around Young Moving Group Stars

    NASA Astrophysics Data System (ADS)

    Biller, B.; Liu, M.; Wahhaj, Z.; Nielsen, E.; NICI Campaign Team

    2014-03-01

    We report results of a direct imaging survey for giant planets around 80 members of the β Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini/NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of ΔH = 13.9 mag at 1'' in combined CH4 narrowband ADI+SDI mode and median contrasts of ΔH = 15.1 mag at 2'' in H-band ADI mode. Four co-moving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36 ± 6 MJup, 16.4 ± 1.0 AU), CDñ35 2722B (31 ± 8 M Jup, 67 ± 4 AU), HD 12894B (0.46 ± 0.08 M., 15.7 ± 1.0 AU), and BD+07 1919C (0.20 ± 0.03 M., 12.5 ± 1.4 AU). From a Bayesian analysis of the achieved H band ADI and ASDI contrasts, using power-law models of planet distributions and hot-start evolutionary models, we restrict the frequency of 1-20 MJup companions at semi-major axes from 10-150 AU to <18% at a 95.4% confidence level using DUSTY models and to <6% at a 95.4% using COND models. This survey is the deepest search to date for giant planets around young moving group stars.

  14. Gulf Coast area from Texas to Louisiana seen from the Gemini 12 spacecraft

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Gulf Coast area from Matagorda Bay, Texas to Vermillion Bay, Louisiana, looking east, as seen from the Gemini 12 spacecraft during its 44th revolution of the earth. Galveston Bay is in center of picture. Houston and its environs are clearly visible. Note network of freeways and superhighways. Large lake near left center of picture is the Sam Rayburn Reservoir.

  15. U.S. Gulf Coast as seen from Gemini 11 spacecraft

    NASA Technical Reports Server (NTRS)

    1966-01-01

    U.S. Gulf coast area from Aransas Bay, Texas to Mobile Bay, Alabama, as seen from the Gemini 11 spacecraft during its 29th revolution of the earth. The Galveston Bay and Houston area is in center of photograph. Further eastward along the coast can be seen the Mississippi River delta and New Orleans area.

  16. Crewmen of the U.S.S. Wasp watching recovery of Gemini 7 spacecraft

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Crewmen of the aircraft carrier U.S.S. Wasp gather on deck to watch the recovery of the Gemini 7 spacecraft and astronauts. Note the signs hanging from the railings which say 'Seasons Greetings from WASP' and 'Spirit of 76'.

  17. Crewmen of the U.S.S. Wasp watching recovery of Gemini 6 spacecraft

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Crewmen of the aircraft carrier U.S.S. Wasp gather on deck to watch the recovery of the Gemini 6 spacecraft and astronauts. Note the signs hanging from the railings which say 'Seasons Greetings from WASP' and 'Spirit of 76'.

  18. Gemini 12 crew cut cake aboard U.S.S. Wasp

    NASA Technical Reports Server (NTRS)

    1966-01-01

    A happy Gemini 12 prime crew slice a cake made aboard the aircraft carrier, U.S.S. Wasp. Astronauts James A. Lovell Jr. (left), command pilot, and Edwin E. Aldrin Jr., pilot, had just been picked up from the splashdown area by helicopter.

  19. Gemini 9-A astronauts welcomed aboard U.S.S. Wasp

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Astronauts Thomas Stafford and Eugene Cernan (right) receive a warm welcome as they arrive aboard the prime recovery ship, the aircraft carrier U.S.S. Wasp. John C. Stonesifer, with the Manned Spacecraft Center's Landing and Recovery Division, stands next to microphone at left. The Gemini 9 spacecraft can be seen in the right background of the view.

  20. Some results of biomedical studies carried out in the Gemini and Apollo programs

    NASA Technical Reports Server (NTRS)

    Kopanev, V. I.; Yuganov, Y. M.

    1975-01-01

    Biomedical changes in Gemini and Apollo astronauts indicate physiological shifts in the majority of organs and systems of the body during space flight. Weightlessness conditions affected body weight, blood circulation, hematological indices, metabolisms, etc. Prophylactic measures to minimize the various physiological and psychological effects constitute activity and rest cycles, supplementary potassium addition to space food, artificial gravity, etc.

  1. Cationic gemini surfactants with cleavable spacer: chemical hydrolysis, biodegradation, and toxicity.

    PubMed

    Tehrani-Bagha, A R; Holmberg, K; van Ginkel, C G; Kean, M

    2015-07-01

    The paper describes synthesis and characterization of a new type of cationic gemini surfactant, which has dodecyl tails and a spacer that contains an ester bond. The nomenclature used to describe the structure is 12Q2OCO1Q12, with Q being a quaternary ammonium group and the numbers indicating the number of methylene or methyl groups. Due to the close proximity to the two quaternary ammonium groups, the ester bond is very stable on the acid side and very labile already at slightly alkaline conditions. The hydrolysis products are two single chain surfactants (i.e. 12Q2OH and 12Q1COOH) which are less surface active than the intact gemini surfactant. 12Q2OCO1Q12 was found to be readily biodegradable, i.e. it gave more than 60% biodegradation after 28 days. This is interesting because similar gemini surfactants but with ester bonds in the tails instead of the spacer, have previously been found not to be readily biodegradable. The gemini surfactant was found to be toxic to aquatic organisms (ErC50 value of 0.27 mg/l), although less toxic than the two hydrolysis products.

  2. Gemini 11 Commander Conrad and Pilot Gordon at post flight press conference

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Gemini 11 Commander Charles Conrad, Jr (left) and Pilot Richard F. Gordon, Jr describe mission activities during their post flight press conference at JSC. Gordon at the microphone talks about the extravehicular activity (EVA) photo projected behind the two crewmembers. During the EVA Gordon attached a tether to the Agena and retrieved a nuclear emulsion experiment package.

  3. Performance of the Gemini Planet Imager’s adaptive optics system

    DOE PAGES

    Poyneer, Lisa A.; Palmer, David W.; Macintosh, Bruce; Savransky, Dmitry; Sadakuni, Naru; Thomas, Sandrine; Véran, Jean-Pierre; Follette, Katherine B.; Greenbaum, Alexandra Z.; Mark Ammons, S.; et al

    2016-01-07

    The Gemini Planet Imager’s adaptive optics (AO) subsystem was designed specifically to facilitate high-contrast imaging. We give a definitive description of the system’s algorithms and technologies as built. Ultimately, the error budget indicates that for all targets and atmospheric conditions AO bandwidth error is the largest term.

  4. Gemini 4 prime crew with Official medical nurse for Astronaut crew members

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Gemini 4 prime crew, Astronauts Edward H. White II, (left), and James A. McDivitt (right) are shown with Lt. Dolores (Dee) O'Hare, US Air Force, Center Medical Office, Flight Medicine Branch, Manned Spaceflight Center (MSC). Lieutenant O'Hare has served during several space flights as Official medical nurse for the astronaut crew members on the missions.

  5. Biodegradability and aquatic toxicity of quaternary ammonium-based gemini surfactants: Effect of the spacer on their ecological properties.

    PubMed

    Garcia, M Teresa; Kaczerewska, Olga; Ribosa, Isabel; Brycki, Bogumił; Materna, Paulina; Drgas, Małgorzata

    2016-07-01

    Aerobic biodegradability and aquatic toxicity of five types of quaternary ammonium-based gemini surfactants have been examined. The effect of the spacer structure and the head group polarity on the ecological properties of a series of dimeric dodecyl ammonium surfactants has been investigated. Standard tests for ready biodegradability assessment (OECD 310) were conducted for C12 alkyl chain gemini surfactants containing oxygen, nitrogen or a benzene ring in the spacer linkage and/or a hydroxyethyl group attached to the nitrogen atom of the head groups. According to the results obtained, the gemini surfactants examined cannot be considered as readily biodegradable compounds. The negligible biotransformation of the gemini surfactants under the standard biodegradation test conditions was found to be due to their toxic effects on the microbial population responsible for aerobic biodegradation. Aquatic toxicity of gemini surfactants was evaluated against Daphnia magna. The acute toxicity values to Daphnia magna, IC50 at 48 h exposure, ranged from 0.6 to 1 mg/L. On the basis of these values, the gemini surfactants tested should be classified as toxic or very toxic to the aquatic environment. However, the dimeric quaternary ammonium-based surfactants examined result to be less toxic than their corresponding monomeric analogs. Nevertheless the aquatic toxicity of these gemini surfactants can be reduced by increasing the molecule hydrophilicity by adding a heteroatom to the spacer or a hydroxyethyl group to the polar head groups. PMID:27045632

  6. Feeding versus feedback in NGC 1068 probed with Gemini NIFS - I. Excitation

    NASA Astrophysics Data System (ADS)

    Riffel, Rogemar A.; Vale, Tiberio B.; Storchi-Bergmann, Thaisa; McGregor, Peter J.

    2014-07-01

    We present emission-line flux distributions and ratios for the inner ≈200 pc of the narrow-line region (NLR) of the Seyfert 2 galaxy NGC 1068, using observations obtained with the Gemini Near-infrared Integral Field Spectrograph (NIFS) in the J, H and K bands at a spatial resolution of ≈10 pc and spectral resolution of ≈5300. The molecular gas emission - traced by the K-band H2 emission lines - outlines an off-centred circumnuclear ring with a radius of ≈100 pc showing thermal excitation. The ionized gas emission lines show flux distributions mostly outlining the previously known [O III] λ5007 ionization bi-cone. But while the flux distributions in the H I and He II emission lines are very similar to that observed in [O III], the flux distribution in the [Fe II] emission lines is more extended and broader than a cone close to the nucleus, showing a `double bowl' or `hourglass' structure. This difference is attributed to the fact that the [Fe II] emission, besides coming from the fully ionized region, comes also from the more extended partially ionized regions, in gas excited mainly by X-rays from the active galactic nucleus. A contribution to the [Fe II] emission from shocks along the bi-cone axis to north-east and south-west of the nucleus is also supported by the enhancement of the [Fe II](1.2570 μm)/[P II](1.1885 μm) and [Fe II](1.2570 μm)/Paβ emission-line ratios at these locations and is attributed to the interaction of the radio jet with the NLR. The mass of ionized gas in the inner 200 pc of NGC 1068 is MH II ≈ 2.2 × 104 M⊙, while the mass of the H2 emitting gas is only MH2 ≈ 29 M⊙. Taking into account the dominant contribution of the cold molecular gas, we obtain an estimate of the total molecular gas mass of Mcold ≈ 2 × 107 M⊙.

  7. Theoretical model to investigate the alkyl chain and anion dependent interactions of gemini surfactant with bovine serum albumin.

    PubMed

    Vishvakarma, Vijay K; Kumari, Kamlesh; Patel, Rajan; Dixit, V S; Singh, Prashant; Mehrotra, Gopal K; Chandra, Ramesh; Chakrawarty, Anand Kumar

    2015-05-15

    Surfactants are used to prevent the irreversible aggregation of partially refolded proteins and they also assist in protein refolding. We have reported the design and screening of gemini surfactant to stabilize bovine serum albumin (BSA) with the help of computational tool (iGEMDOCK). A series of gemini surfactant has been designed based on bis-N-alkyl nicotinate dianion via varying the alkyl group and anion. On changing the alkyl group and anion of the surfactant, the value of Log P changes means polarity of surfactant can be tuned. Further, the virtual screening of the gemini surfactant has been carried out based on generic evolutionary method. Herein, thermodynamic data was studied to determine the potential of gemini surfactant as BSA stabilizer. Computational tools help to find out the efficient gemini surfactant to stabilize the BSA rather than to use the surfactant randomly and directionless for the stabilization. It can be confirmed through the experimental techniques. Previously, researcher synthesized one of the designed and used gemini surfactant to stabilize the BSA and their interactions were confirmed through various techniques and computational docking. But herein, the authors find the most competent gemini surfactant to stabilize BSA using computational tools on the basis of energy score. Different from the single chain surfactant, the gemini surfactants exhibit much stronger electrostatic and hydrophobic interactions with the protein and are thus effective at much lower concentrations. Based on the present study, it is expected that gemini surfactants may prove useful in the protein stabilization operations and may thus be effectively employed to circumvent the problem of misfolding and aggregation.

  8. ASTRO-1: a 1.8m unobscured space observatory for next generation UV/visible astrophysics and exoplanet exploration

    NASA Astrophysics Data System (ADS)

    Matthews, Gary W.; Egerman, Robert; Morse, Jon A.; Wilkes, Belinda

    2016-07-01

    The Hubble Space Telescope has been a scientific marvel that has provided unimaginable imagery and scientific discovery. Its exquisite UV/Visible imaging performance is unmatched from the ground. In NASA's future planning, the earliest possible successor mission would be in the 3030s, well beyond the expected lifetime of Hubble. The ASTRO-1 space telescope is a 1.8m off-axis (unobscured) observatory that looks to fill this critical void with Hubble-like performance to continue the scientific quest while also providing the possibility for exoplanet research with a coronagraphic instrument and/or a free flying starshade. BoldlyGo Institute seeks to reach beyond NASA funding to leverage the high public interest in space research and exploration, and the search for life beyond Earth.

  9. Stellar Archaeology and Galaxy Genesis: The Need for Large Area Multi-Object Spectrograph on 8 m-Class Telescopes

    NASA Astrophysics Data System (ADS)

    Irwin, Mike J.; Lewis, Geraint F.

    The origin and evolution of galaxies like the Milky Way and M31 remain among the key questions in astrophysics. The galaxies we see today in and around the Local Group are representatives of the general field population of the Universe and have been evolving for the majority of cosmic time. As our nearest neighbour systems they can be studied in far more detail than their distant counterparts and hence provide our best hope for understanding star formation and prototypical galaxy evolution over the lifetime of the Universe [K. Freeman, J. Bland-Hawthorn in Annu. Rev. Astron. Astrophys. 40, 487 (2002)]. Significant observational progress has been made, but we are still a long way from understanding galaxy genesis. To unravel this formative epoch, detailed large area multi-object spectroscopy of spatial, kinematic and chemical structures on 8 m-class telescopes are required, to provide the link between local near-field cosmology and predictions from the high-redshift Universe.

  10. Gemini Spectroscopy of Supernovae from the Supernova Legacy Survey: Improving High-Redshift Supernova Selection and Classification

    NASA Astrophysics Data System (ADS)

    Howell, D. A.; Sullivan, M.; Perrett, K.; Bronder, T. J.; Hook, I. M.; Astier, P.; Aubourg, E.; Balam, D.; Basa, S.; Carlberg, R. G.; Fabbro, S.; Fouchez, D.; Guy, J.; Lafoux, H.; Neill, J. D.; Pain, R.; Palanque-Delabrouille, N.; Pritchet, C. J.; Regnault, N.; Rich, J.; Taillet, R.; Knop, R.; McMahon, R. G.; Perlmutter, S.; Walton, N. A.

    2005-12-01

    We present new techniques for improving the efficiency of supernova (SN) classification at high redshift using 64 candidates observed at Gemini North and South during the first year of the Supernova Legacy Survey (SNLS). The SNLS is an ongoing 5 year project with the goal of measuring the equation of state of dark energy by discovering and following over 700 high-redshift SNe Ia using data from the Canada-France-Hawaii Telescope Legacy Survey. We achieve an improvement in the SN Ia spectroscopic confirmation rate: at Gemini 71% of candidates are now confirmed as SNe Ia, compared to 54% using the methods of previous surveys. This is despite the comparatively high redshift of this sample, in which the median SN Ia redshift is z=0.81 (0.155<=z<=1.01). These improvements were realized because we use the unprecedented color coverage and light curve sampling of the SNLS to predict whether a candidate is a SN Ia and to estimate its redshift, before obtaining a spectrum, using a new technique called the ``SN photo-z.'' In addition, we have improved techniques for galaxy subtraction and SN template χ2 fitting, allowing us to identify candidates even when they are only 15% as bright as the host galaxy. The largest impediment to SN identification is found to be host galaxy contamination of the spectrum-when the SN was at least as bright as the underlying host galaxy the target was identified more than 90% of the time. However, even SNe in bright host galaxies can be easily identified in good seeing conditions. When the image quality was better than 0.55", the candidate was identified 88% of the time. Over the 5 year course of the survey, using the selection techniques presented here, we will be able to add ~170 more confirmed SNe Ia than would be possible using previous methods. APC, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France. DSM/DAPNIA, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France.

  11. Solution properties and emulsification properties of amino acid-based gemini surfactants derived from cysteine.

    PubMed

    Yoshimura, Tomokazu; Sakato, Ayako; Esumi, Kunio

    2013-01-01

    Amino acid-based anionic gemini surfactants (2C(n)diCys, where n represents an alkyl chain with a length of 10, 12, or 14 carbons and "di" and "Cys" indicate adipoyl and cysteine, respectively) were synthesized using the amino acid cysteine. Biodegradability, equilibrium surface tension, and dynamic light scattering were used to characterize the properties of gemini surfactants. Additionally, the effects of alkyl chain length, number of chains, and structure on these properties were evaluated by comparing previously reported gemini surfactants derived from cystine (2C(n)Cys) and monomeric surfactants (C(n)Cys). 2C(n)diCys shows relatively higher biodegradability than does C(n)Cys and previously reported sugar-based gemini surfactants. Both critical micelle concentration (CMC) and surface tension decrease when alkyl chain length is increased from 10 to 12, while a further increase in chain length to 14 results in increased CMC and surface tension. This indicates that long-chain gemini surfactants have a decreased aggregation tendency due to the steric hindrance of the bulky spacer as well as premicelle formation at concentrations below the CMC and are poorly packed at the air/water interface. Formation of micelles (measuring 2 to 5 nm in solution) from 2C(n)diCys shows no dependence on alkyl chain length. Further, shaking the mixtures of aqueous 2C(n)diCys surfactant solutions and squalane results in the formation of oil-in-water type emulsions. The highly stable emulsions are formed using 2C₁₂diCys or 2C₁₄diCys solution and squalane in a 1:1 or 2:1 volume ratio.

  12. Growth Behavior, Geometrical Shape, and Second CMC of Micelles Formed by Cationic Gemini Esterquat Surfactants.

    PubMed

    Bergström, L Magnus; Tehrani-Bagha, Alireza; Nagy, Gergely

    2015-04-28

    Micelles formed by novel gemini esterquat surfactants have been investigated with small-angle neutron scattering (SANS). The growth behavior of the micelles is found to differ conspicuously depending on the length of the gemini surfactant spacer group. The gemini surfactant with a long spacer form rather small triaxial ellipsoidal tablet-shaped micelles that grow weakly with surfactant concentration in the entire range of measured concentrations. Geminis with a short spacer, on the other hand, form weakly growing oblates or tablets at low concentrations that start to grow much more strongly into polydisperse rodlike or wormlike micelles at higher concentrations. The latter behavior is consistent with the presence of a second CMC that marks the transition from the weakly to the strongly growing regime. It is found that the growth behavior in terms of aggregation number as a function of surfactant concentration always appear concave in weakly growing regimes, while switching to convex behavior in strongly growing regimes. As a result, we are able to determine the second CMC of the geminis with short spacer by means of suggesting a rather precise definition of it, located at the point of inflection of the growth curve that corresponds to the transition from concave to convex growth behavior. Our SANS results are rationalized by comparison with the recently developed general micelle model. In particular, this theory is able to explain and reproduce the characteristic appearances of the experimental growth curves, including the presence of a second CMC and the convex strongly growing regime beyond. By means of optimizing the agreement between predictions from the general micelle model and results from SANS experiments, we are able to determine the three bending elasticity constants spontaneous curvature, bending rigidity, and saddle-splay constant for each surfactant. PMID:25835031

  13. Synthesis and Electrochemical Characterization of M2Mn3O8 (M=Ca,Cu) Compounds and Derivatives

    SciTech Connect

    Park, Yong Joon; Doeff, Marca M.

    2005-08-25

    M{sub 2}Mn{sub 3}O{sub 8} (M=Ca{sup 2+}, Cu{sup 2+}) compounds were synthesized and characterized in lithium cells. The M{sup 2+} cations, which reside in the van der Waal's gaps between adjacent sheets of Mn{sub 3}O{sub 8}{sup 4-}, may be replaced chemically (by ion-exchange) or electrochemically with Li. More than 7 Li{sup +}/Cu{sub 2}Mn{sub 3}O{sub 8} may be inserted electrochemically, with concomitant reduction of Cu{sup 2+} to Cu metal, but less Li can be inserted into Ca{sub 2}Mn{sub 3}O{sub 8}. In the case of Cu{sup 2+}, this process is partially reversible when the cell is charged above 3.5 V vs. Li, but intercalation of Cu{sup +} rather than Cu{sup 2+} and Li{sup +}/Cu{sup +} exchange occurs during the subsequent discharge. If the cell potential is kept below 3.4 V, the Li in excess of 4Li{sup +}/Cu{sub 2}Mn{sub 3}O{sub 8} can be cycled reversibly. The unusual mobility of +2 cations in a layered structure has important implications both for the design of cathodes for Li batteries and for new systems that could be based on M{sup 2+} intercalation compounds.

  14. Mechanized welding of a Christmans tree of 06Kh20N8M3D2L steel

    SciTech Connect

    Leibzon, V.M.; kakhramanov, V.T.; Eshtokin, V.I.; Fataliev, S.O.; Fisher, V.O.; Pavlov, A.A.

    1986-03-01

    The most critical fitting of a well for the recovery of petroleum and gas with a high content of corrosive constituents is made of 06Kh20N8M3D2L steel. The quality, reliability, and life of a Christmas tree are determined primarily by the mechanical and corrosion properties of the weld joint. The authors report on the improvement of the existing method for welding the units of a Christmas tree. Argon and carbon dioxide were used as the protective medium in semiautomatic welding. The welding was done with a reverse polarity dc. An analysis of the data presented shows that the closest content to the base metal of chromium and nickel in the joint are provided in welding with OZL-41 electrodes. The molybdenum content in the joints welded with NZh-13 electrodes and Sv-08Kh19N10M38B wire in argon and carbon dioxide is at the level of the content of this element in the base metal.

  15. Tests of Dynamic Scale Model of Gemini Capsule in the Langley 20-Foot Free-Spinning Tunnel

    NASA Technical Reports Server (NTRS)

    1962-01-01

    Tests of Dynamic Scale Model of Gemini Capsule in the Langley 20-Foot Free-Spinning Tunnel. The film shows three spin tunnel tests of a 1/20 scale model of the Gemini capsule. In the first test, the capsule spins freely. In tests 2 and 3, a drogue parachute is attached to the capsule. [Entire movie available on DVD from CASI as Doc ID 20070030989. Contact help@sti.nasa.gov

  16. Efficient improvement of surface activity of tea saponin through Gemini-like modification by straightforward esterification.

    PubMed

    Feng, Jin; Chen, Ying; Liu, Xin; Liu, Songbai

    2015-03-15

    Novel strategy of Gemini-like modification has been applied in development of new nonionic surfactants, tea saponin esters, with enhanced surface activity by simple esterification. Tea saponin was treated with acyl chlorides of different chain length and different ratio of tea saponin and acyl chloride under alkaline condition. The structures of tea saponin esters were analysed and confirmed by FT-IR, NMR and ESI-MS. Surface activity investigation revealed that esterification with the chain length of C12 and C14 and the ratio of 1:4 to 1:6 produced superior surface activity compared with tea saponin. The exceptional surface activity of the new surfactants suggested their great potential application in food industry as green surfactants due to their environmental benign nature as well as simple and inexpensive preparation. The strategy of Gemini-like modification will facilitate development of green surfactants based on natural resources.

  17. A new MOS mask cutter facility at Gemini/Cerro Tololo observatories

    NASA Astrophysics Data System (ADS)

    Wyman, Robert T.; Trancho, Gelys; Tighe, Roberto

    2010-07-01

    The installation and commissioning of a new laser cutter facility in La Serena, Chile is a cooperative effort between Gemini Observatory and the Cerro Tololo Inter-American Observatory. This system enables the cutting of aluminum and carbon fiber slit masks for three multi-object spectrographs operating in Chile: GMOS-S, Flamingos-2, and Goodman spectrograph. Selection of the new laser cutter tool was based on slit mask specifications developed for two materials. Prior to the commissioning all slit mask production was performed at Gemini's Northern base facility with a similar laser cutter system. The new facility supports two observatories and enhances the capabilities for both. This paper will discuss the observatory arrangement with respect to mask data tracking and handling. The laser system and facility will be discussed along with mask cutting performance, process development and manufacturing methods.

  18. Integrating the Galileoscope into Successfully Established as Well as New Outreach Programs at Gemini Observatory

    NASA Astrophysics Data System (ADS)

    Harvey, J.; Michaud, P.; Slater, T.; Slater, S.; Goldstein, J.

    2011-09-01

    The annual Journey through the Universe program is a flagship Gemini public education/outreach event that engages the public, teachers, astronomers, engineers, and thousands of local students and staff from all of the Mauna Kea Observatories. Now going into its seventh year in Hawaii, the 2010 program has integrated the Galileoscope as an integral part of the ten-day program with teacher workshops, classroom telescope kits, and a new teacher resource package developed for the program. Through the generous donation of Galileoscopes from the Ric and Jean Edelman Foundation and the Astronomical Society of the Pacific, each Project/Family Astro site received Galileoscopes. Each family participating in Gemini's Family Astro event and training program will receive a Galileoscope to take home. Workshops will be offered to the Girl and Boy scouts, the Boys and Girls Club of Hawaii, the County of Hawaii's Department of Parks and Recreation's summer programs, and other community organizations.

  19. Magnetic measurement data of the 0.8-m prototype quadrupole magnets for the APS storage ring

    SciTech Connect

    Kim, S.H.

    1995-07-01

    From magnetic measurement data of the two 0.8-m prototype quadrupole magnets (P-SRQ-1 and P-SRQ-2) and the study of the geometries for the pole-end bevels and pole chamfers, the following conclusions have been made. Mechanical stability of the magnet poles has been achieved by modification of the weld procedures between two quadrants of the magnets. Stability of the magnet-pole positions was measured optically and was also concluded from the fact that the allowed coefficients, mainly sextupole and octupole terms, were independent of the magnet excitation currents. Unallowed multipole field coefficients for the second magnet, without correction of the magnet-pole positions, are smaller than for the first magnet. The field gradient integrals of the two magnets at 400A differ by less than 5 {times} 10{sup {minus}4} for r = 2.5 cm. This indicates that an acceptable magnet assembly procedure has been established. The 2-D calculations and ``body`` measurements for allowed coefficients after the main field, b{sub 5} and b{sub 9}, agree within 1.2 {times} 10{sup {minus}4} at r = 2.5 cm. This implies that the 2-D design geometry is basically correct and acceptable. As expected for a magnet with long and narrow poles, saturation effects of pole shims have been observed. In order to reduce fabrication cost for the end-plates, the geometries for the pole-end bevels and pole chamfers have been studied. By choosing a bevel angle of 61{degree}, instead of 45{degree}, it is possible to have acceptable allowed coefficients with dimensions of pole-chamfers up to 16.5 mm. This allows the design of the end-plate as one piece without removable pole-tip.

  20. TOWARD PRECISION PHOTOMETRY FOR THE ELT ERA: THE DOUBLE SUBGIANT BRANCH OF NGC 1851 OBSERVED WITH THE GEMINI/GeMS MCAO SYSTEM

    SciTech Connect

    Turri, P.; McConnachie, A. W.; Stetson, P. B.; Andersen, D. R.; Véran, J.-P.; Fiorentino, G.; Bono, G.

    2015-10-01

    The Extremely Large Telescopes currently under construction have a collecting area that is an order of magnitude larger than the present largest optical telescopes. For seeing-limited observations the performance will scale as the collecting area, but with the successful use of adaptive optics (AO), for many applications it will scale as D{sup 4} (where D is the diameter of the primary mirror). Central to the success of the ELTs, therefore, is the successful use of multi-conjugate adaptive optics (MCAO) which applies a high degree of correction over a field of view larger than the few arcseconds that limits classical AO systems. In this Letter, we report on the analysis of crowded field images taken on the central region of the galactic globular cluster NGC 1851 in the K{sub s} band using the Gemini Multi-conjugate Adaptive Optics System (GeMS) at the Gemini South Telescope, the only science-grade MCAO system in operation. We use this cluster as a benchmark to verify the ability to achieve precise near-infrared photometry by presenting the deepest K{sub s} photometry in crowded fields ever obtained from the ground. We construct a color–magnitude diagram in combination with the F606W band from the Hubble Space Telescope/Advanced Camera for Surveys. As well as detecting the “knee” in the lower main sequence at K{sub s} ≃ 20.5, we also detect the double subgiant branch of NGC 1851, which demonstrates the high photometric accuracy of GeMS in crowded fields.

  1. Toward Precision Photometry for the ELT Era: The Double Subgiant Branch of NGC 1851 Observed with the Gemini/GeMS MCAO System

    NASA Astrophysics Data System (ADS)

    Turri, P.; McConnachie, A. W.; Stetson, P. B.; Fiorentino, G.; Andersen, D. R.; Véran, J.-P.; Bono, G.

    2015-10-01

    The Extremely Large Telescopes currently under construction have a collecting area that is an order of magnitude larger than the present largest optical telescopes. For seeing-limited observations the performance will scale as the collecting area, but with the successful use of adaptive optics (AO), for many applications it will scale as D4 (where D is the diameter of the primary mirror). Central to the success of the ELTs, therefore, is the successful use of multi-conjugate adaptive optics (MCAO) which applies a high degree of correction over a field of view larger than the few arcseconds that limits classical AO systems. In this Letter, we report on the analysis of crowded field images taken on the central region of the galactic globular cluster NGC 1851 in the Ks band using the Gemini Multi-conjugate Adaptive Optics System (GeMS) at the Gemini South Telescope, the only science-grade MCAO system in operation. We use this cluster as a benchmark to verify the ability to achieve precise near-infrared photometry by presenting the deepest Ks photometry in crowded fields ever obtained from the ground. We construct a color-magnitude diagram in combination with the F606W band from the Hubble Space Telescope/Advanced Camera for Surveys. As well as detecting the “knee” in the lower main sequence at Ks ≃ 20.5, we also detect the double subgiant branch of NGC 1851, which demonstrates the high photometric accuracy of GeMS in crowded fields.

  2. Lipoplexes of dicationic gemini surfactants with DNA: Structural features of DNA compaction and transfection efficiency.

    PubMed

    Faizullin, D A; Zuev, Yu F; Zakharova, L Ya; Pokrovsky, A G; Korobeinikov, V A; Mukhametzyanov, T A; Konovalov, A I

    2015-01-01

    The internal structure of DNA lipoplexes with hydroxyethylated alkylammonium gemini surfactants (GS) with high transfection activity was studied by circular dichroism. It was shown that the efficiency of transfection of HEK293T cells with the pEGFP-N1 circular plasmid was different from zero only in the region of existence of chiral supramolecular DNA-GS complexes and reaches a maximum at concentrations at which the spontaneous aggregation of components is observed.

  3. Topical Non-Invasive Gene Delivery using Gemini Nanoparticles in Interferon-gamma-deficient Mice

    SciTech Connect

    Badea,I.; Wettig, S.; Verrall, R.; Foldvari, M.

    2007-01-01

    Cutaneous gene therapy, although a promising approach for many dermatologic diseases, has not progressed to the stage of clinical trials, mainly due to the lack of an effective gene delivery system. The main objective of this study was to construct and evaluate gemini nanoparticles as a topical formulation for the interferon gamma (IFN-{gamma}) gene in an IFN-{gamma}-deficient mouse model. Nanoparticles based on the gemini surfactant 16-3-16 (NP16-DNA) and another cationic lipid cholesteryl 3{beta}-(-N-[dimethylamino-ethyl] carbamate) [Dc-chol] (NPDc-DNA) were prepared and characterized. Zetasizer measurement indicated a bimodal distribution of 146 and 468 nm average particle sizes for the NP16-DNA ({zeta}-potential +51 mV) nanoparticles and monomodal distribution of 625 nm ({zeta}-potential +44 mV) for the NPDc-DNA. Circular dichroism studies showed that the gemini surfactant compacted the plasmid more efficiently compared to the Dc-chol. Small-angle X-ray scattering measurements revealed structural polymorphism in the NP16-DNA nanoparticles, with lamellar and Fd3m cubic phases present, while for the NPDc-DNA two lamellar phases could be distinguished. In vivo, both topically applied nanoparticles induced higher gene expression compared to untreated control and naked DNA (means of 0.480 and 0.398 ng/cm{sup 2} vs 0.067 and 0.167 ng/cm{sup 2}). However, treatment with NPDc-DNA caused skin irritation, and skin damage, whereas NP16-DNA showed no skin toxicity. In this study, we demonstrated that topical cutaneous gene delivery using gemini surfactant-based nanoparticles in IFN-{gamma}-deficient mice was safe and may provide increased gene expression in the skin due to structural complexity of NP16 nanoparticles (lamellar-cubic phases).

  4. Structure activity relationships in alkylammonium C12-gemini surfactants used as dermal permeation enhancers.

    PubMed

    Silva, Sérgio M C; Sousa, João J S; Marques, Eduardo F; Pais, Alberto A C C; Michniak-Kohn, Bozena B

    2013-10-01

    The purpose of this study was to determine the ability and the safety of a series of alkylammonium C12-gemini surfactants to act as permeation enhancers for three model drugs, namely lidocaine HCl, caffeine, and ketoprofen. In vitro permeation studies across dermatomed porcine skin were performed over 24 h, after pretreating the skin for 1 h with an enhancer solution 0.16 M dissolved in propylene glycol. The highest enhancement ratio (enhancement ratio (ER)=5.1) was obtained using G12-6-12, resulting in a cumulative amount of permeated lidocaine HCl of 156.5 μg cm−2. The studies with caffeine and ketoprofen revealed that the most effective gemini surfactant was the one with the shorter spacer, G12-2-12. The use of the latter resulted in an ER of 2.4 and 2.2 in the passive permeation of caffeine and ketoprofen, respectively. However, Azone was found to be the most effective permeation enhancer for ketoprofen, attaining a total of 138.4 μg cm−2 permeated, 2.7-fold over controls. This work demonstrates that gemini surfactants are effective in terms of increasing the permeation of drugs, especially in the case of hydrophilic ionized compounds, that do not easily cross the stratum corneum. Skin integrity evaluation studies did not indicate the existence of relevant changes in the skin structure after the use of the permeation enhancers, while the cytotoxicity studies allowed establishing a relative cytotoxicity profile including this class of compounds, single chain surfactants, and Azone. A dependence of the toxicity to HEK and to HDF cell lines on the spacer length of the various gemini molecules was found. PMID:23959685

  5. Questions and Answers for Ken Thomas' "Intra-Extra Vehicular Activity Russian and Gemini Spacesuits" Presentation

    NASA Technical Reports Server (NTRS)

    Thomas, Kenneth S.

    2016-01-01

    Kenneth Thomas will discuss the Intra-Extra Vehicular Activity Russian & Gemini spacesuits. While the United States and Russia adapted to existing launch- and reentry-type suits to allow the first human ventures into the vacuum of space, there were differences in execution and capabilities. Mr. Thomas will discuss the advantages and disadvantages of this approach compared to exclusively intravehicular or extra-vehicular suit systems.

  6. Gemini Spectroscopy of Galactic Bulge Sources: A Population of Hidden Accreting Binaries Revealed?

    NASA Astrophysics Data System (ADS)

    Wu, Jianfeng; Jonker, Peter; Torres, Manuel; Britt, Christopher; Johnson, Chris; Hynes, Robert I.; Greiss, Sandra; Steeghs, Danny; Maccarone, Tom; Heinke, Craig O.; Wevers, Thomas

    2015-01-01

    We present Gemini spectroscopy for 21 X-ray sources detected in the Galactic Bulge Survey (GBS), which aims to investigate X-ray binaries in the Galactic Bulge region. For the majority of the sources, we have obtained spectra of the objects that are likely the real optical counterparts to the X-ray sources. Line measurements, spectral classification, and radial velocity analysis were performed on the Gemini spectra. We discover a population of hidden accreting binaries whose Gemini spectra apparently show neither strong Hα emission nor Hα absorption. However, the residual spectra of some sources after subtracting the best-fit stellar spectroscopic templates contain a broad Hα emission line which likely originates in an accretion disk. These hidden accreting sources may constitute a substantial portion of the full accreting binary population. We also identify three likely candidates of eclipsing or high-inclination quiescent low-mass X-ray binaries based on their broad Hα emission line profile and/or their optical light curves. Significant Hα emission line variability was also observed for two GBS sources.

  7. Genetic diversity of Mexican brook lamprey Lampetra (Tetrapleurodon) geminis (Alvarez del Villar, 1966).

    PubMed

    Mejía, Omar; Polaco, Oscar J; Zúñiga, Gerardo

    2004-11-01

    Lampreys are the only surviving representatives of the oldest known vertebrates. The Mexican lamprey L. geminis (nonparasitic), is particularly interesting, because it is an endemic, biogeographical relict, and a threatened species. RAPD markers were used to describe genetic diversity in L. geminis. A total of 77 specimens were collected from five populations, three in the Río Grande de Morelia-Cuitzeo basin and two in the Río Duero-Lerma-Chapala basin, México. Eighty-eight RAPD markers were obtained from eight primers. Genetic diversity within each population was estimated using Shannon's index (S), heterozygosity (H) and gene diversity (h). These estimates revealed significant variation within populations, although a variance homogeneity test (HOMOVA) showed no significant differences among populations or between basins. Nei genetic distance values indicate a low genetic differentiation among populations. Analysis of molecular variance (AMOVA) indicates that most of the genetic diversity occurs within populations (91.4%), but that a statistically significant amount is found among populations (P < 0.001). Principal coordinates and cluster analyses of RAPD phenotypes show that specimens are not grouped by geographical origin. The genetic diversity found within L. geminis populations may be explained by its breeding system and an overlapping of generations. The scarce genetic differentiation among populations is likely to the low rate of DNA change that characterizes the lamprey group.

  8. Action of reactive oxygen species in the antifungal mechanism of gemini-pyridinium salts against yeast.

    PubMed

    Shirai, Akihiro; Ueta, Shouko; Maseda, Hideaki; Kourai, Hiroki; Omasa, Takeshi

    2012-06-01

    We previously found that the gemini quaternary salt (gemini-QUAT) containing two pyridinium residues per molecule, 3,3'- (2,7-dioxaoctane) bis (1-decylpyridinium bromide) (3DOBP-4,10) , exerted fungicidal activity against Saccharomyces cerevisiae and caused respiration inhibition and the cytoplasmic leakage of ATP, magnesium, and potassium ions. Here, we investigated how the gemini-QUAT, 3DOBP-4,10, exerts more powerful antimicrobial activity than the mono-QUAT N-cetylpyridinium chloride (CPC) and examined the association between reactive oxygen species (ROS) and the antimicrobial mechanism. Antifungal assays showed that the activity of 3DOBP-4,10 against two yeasts, S. cerevisiae and Candida albicans, was significantly elevated under aerobic conditions, and largely reduced under anaerobic conditions (nitrogen atmosphere) . Adding radical scavengers such as superoxide dismutase, catalase and potassium iodide (KI) also decreased the fungicidal activity of 3DOBP-4,10 but negligibly affected that of CPC. We measured survival under static conditions and found that the rapid fungicidal profile of 3DOBP-4,10 was lost, whereas that of CPC was slightly affected in the presence of KI. Our results suggest that 3DOBP-4,10 exerts powerful antimicrobial activity by penetrating the cell wall and membrane, which then allows oxygen to enter the cells, where it participates in the generation of intracellular ROS. The activity could thus be attributable to a synergic antimicrobial combination of the disruption of organelle membranes by the QUAT and oxidative stress imposed by ROS.

  9. The survival of terrestrial microorganisms in space at orbital altitudes during Gemini satellite experiments.

    PubMed

    Hotchin, J; Lorenz, P; Hemenway, C L

    1968-01-01

    In a previous series of rocket- and satellite-borne experiments, microorganisms were exposed to space between altitudes of 60 to 460 km for periods between 3 minutes and 4 months. The results showed that some of the unprotected microorganisms survived the direct exposure for up to 17 hours. Complete survival was found when the microorganisms were shielded from nonpenetrating radiation. These results made it desirable to systematically study the lethal influence of the space environment on a wider spectrum of unprotected microorganisms over various exposure periods. This communication presents the results of exposure experiments on board the Gemini XII satellite. The microorganisms were dried on plastic coated aluminum plates using techniques which will be described elsewhere. During the flight of the Gemini XII space capsule, the microorganisms were directly exposed to space for approximately 6 1/2 hours. After the successful completion of the Gemini XII mission the payload was returned to the laboratory for elution and titration of the microorganisms using techniques described elsewhere. The results showed that again survival of some microorganisms had occurred. An attempt is made to integrate these results with data obtained in previously published experiments.

  10. Managing target of opportunity (ToO) observations in queue mode at Gemini Observatory

    NASA Astrophysics Data System (ADS)

    Roth, Katherine C.; Carrasco, E. Rodrigo; Miller, Bryan W.; Stephens, Andrew W.; Jørgensen, Inger; Rodgers, Bernadette

    2010-07-01

    Target of opportunity observations (ToO) are an integral part of multi-instrument queue operations at Gemini Observatory. ToOs comprise a significant fraction of the queue (20-25% of the highest ranking band) and with the advent of large survey telescopes (eg. Pan-STARRS, LSST) dedicated to searching for transient events this fraction may reasonably be expected to increase significantly in the coming years. While some important aspects of ToO execution at Gemini Observatory are managed automatically (eg. trigger alerts, data distribution), other areas such as duplications checking, scheduling and relative priority determination still require manual intervention. In order to increase efficiency and improve our commitment to ToOs and queue observing in general, these aspects need to be formalized and incorporated into improved phase 2 checking, automated queue scheduling and on-the-fly nightly plan generation software. We discuss the different flavors of ToOs supported at Gemini Observatory and how each kind is scheduled with respect to existing queue observations. We present ideas for formalizing these practices into a system of dynamical prioritization which automatically self adjusts as new ToO observations are triggered, high priority targets become endangered, and timing windows near expiration.

  11. Implementing an Education and Outreach Program for the Gemini Observatory in Chile.

    NASA Astrophysics Data System (ADS)

    Garcia, M. A.

    2006-08-01

    Beginning in 2001, the Gemini Observatory began the development of an innovative and aggressive education and outreach program at its Southern Hemisphere site in northern Chile. A principal focus of this effort is centered on local education and outreach to communities surrounding the observatory and its base facility in La Serena Chile. Programs are now established with local schools using two portable StarLab planetaria, an internet-based teacher exchange called StarTeachers and multiple partnerships with local educational institutions. Other elements include a CD-ROM-based virtual tour that allows students, teachers and the public to experience the observatory's sites in Chile and Hawaii. This virtual environment allows interaction using a variety of immersive scenarios such as a simulated observation using real data from Gemini. Pilot projects like "Live from Gemini" are currently being developed which use internet videoconferencing technologies to bring the observatory's facilities into classrooms at universities and remote institutions. Lessons learned from the implementation of these and other programs will be introduced and the challenges of developing educational programming in a developing country will be shared.

  12. Action of reactive oxygen species in the antifungal mechanism of gemini-pyridinium salts against yeast.

    PubMed

    Shirai, Akihiro; Ueta, Shouko; Maseda, Hideaki; Kourai, Hiroki; Omasa, Takeshi

    2012-06-01

    We previously found that the gemini quaternary salt (gemini-QUAT) containing two pyridinium residues per molecule, 3,3'- (2,7-dioxaoctane) bis (1-decylpyridinium bromide) (3DOBP-4,10) , exerted fungicidal activity against Saccharomyces cerevisiae and caused respiration inhibition and the cytoplasmic leakage of ATP, magnesium, and potassium ions. Here, we investigated how the gemini-QUAT, 3DOBP-4,10, exerts more powerful antimicrobial activity than the mono-QUAT N-cetylpyridinium chloride (CPC) and examined the association between reactive oxygen species (ROS) and the antimicrobial mechanism. Antifungal assays showed that the activity of 3DOBP-4,10 against two yeasts, S. cerevisiae and Candida albicans, was significantly elevated under aerobic conditions, and largely reduced under anaerobic conditions (nitrogen atmosphere) . Adding radical scavengers such as superoxide dismutase, catalase and potassium iodide (KI) also decreased the fungicidal activity of 3DOBP-4,10 but negligibly affected that of CPC. We measured survival under static conditions and found that the rapid fungicidal profile of 3DOBP-4,10 was lost, whereas that of CPC was slightly affected in the presence of KI. Our results suggest that 3DOBP-4,10 exerts powerful antimicrobial activity by penetrating the cell wall and membrane, which then allows oxygen to enter the cells, where it participates in the generation of intracellular ROS. The activity could thus be attributable to a synergic antimicrobial combination of the disruption of organelle membranes by the QUAT and oxidative stress imposed by ROS. PMID:22790843

  13. THE GEMINI/NICI PLANET-FINDING CAMPAIGN: THE FREQUENCY OF PLANETS AROUND YOUNG MOVING GROUP STARS

    SciTech Connect

    Biller, Beth A.; Ftaclas, Christ; Liu, Michael C.; Wahhaj, Zahed; Nielsen, Eric L.; Hayward, Thomas L.; Hartung, Markus; Chun, Mark; Clarke, Fraser; Thatte, Niranjan; Shkolnik, Evgenya L.; Reid, I. Neill; Boss, Alan; Lin, Douglas; Alencar, Silvia H. P.; De Gouveia Dal Pino, Elisabete; Gregorio-Hetem, Jane [Universidade de Sao Paulo, IAG and others

    2013-11-10

    We report results of a direct imaging survey for giant planets around 80 members of the β Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini/NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of ΔH = 13.9 mag at 1'' in combined CH{sub 4} narrowband ADI+SDI mode and median contrasts of ΔH = 15.1 mag at 2'' in H-band ADI mode. We found numerous (>70) candidate companions in our survey images. Some of these candidates were rejected as common-proper motion companions using archival data; we reobserved with Near-Infrared Coronagraphic Imager (NICI) all other candidates that lay within 400 AU of the star and were not in dense stellar fields. The vast majority of candidate companions were confirmed as background objects from archival observations and/or dedicated NICI Campaign followup. Four co-moving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36 ± 6 M{sub Jup}, 16.4 ± 1.0 AU), CD–35 2722B (31 ± 8 M{sub Jup}, 67 ± 4 AU), HD 12894B (0.46 ± 0.08 M{sub ☉}, 15.7 ± 1.0 AU), and BD+07 1919C (0.20 ± 0.03 M{sub ☉}, 12.5 ± 1.4 AU). From a Bayesian analysis of the achieved H band ADI and ASDI contrasts, using power-law models of planet distributions and hot-start evolutionary models, we restrict the frequency of 1-20 M{sub Jup} companions at semi-major axes from 10-150 AU to <18% at a 95.4% confidence level using DUSTY models and to <6% at a 95.4% using COND models. Our results strongly constrain the frequency of planets within semi-major axes of 50 AU as well. We restrict the frequency of 1-20 M{sub Jup} companions at semi-major axes from 10-50 AU to <21% at a 95.4% confidence level using DUSTY models and to <7% at a 95.4% using COND models. This survey is the deepest search to date for giant planets around young moving group stars.

  14. The Gemini NICI Planet-finding Campaign: Discovery of a Substellar L Dwarf Companion to the Nearby Young M Dwarf CD-35 2722

    NASA Astrophysics Data System (ADS)

    Wahhaj, Zahed; Liu, Michael C.; Biller, Beth A.; Clarke, Fraser; Nielsen, Eric L.; Close, Laird M.; Hayward, Thomas L.; Mamajek, Eric E.; Cushing, Michael; Dupuy, Trent; Tecza, Matthias; Thatte, Niranjan; Chun, Mark; Ftaclas, Christ; Hartung, Markus; Reid, I. Neill; Shkolnik, Evgenya L.; Alencar, Silvia H. P.; Artymowicz, Pawel; Boss, Alan; de Gouveia Dal Pino, Elisabethe; Gregorio-Hetem, Jane; Ida, Shigeru; Kuchner, Marc; Lin, Douglas N. C.; Toomey, Douglas W.

    2011-03-01

    We present the discovery of a wide (67 AU) substellar companion to the nearby (21 pc) young solar-metallicity M1 dwarf CD-35 2722, a member of the ≈100 Myr AB Doradus association. Two epochs of astrometry from the NICI Planet-Finding Campaign confirm that CD-35 2722 B is physically associated with the primary star. Near-IR spectra indicate a spectral type of L4±1 with a moderately low surface gravity, making it one of the coolest young companions found to date. The absorption lines and near-IR continuum shape of CD-35 2722 B agree especially well the dusty field L4.5 dwarf 2MASS J22244381-0158521, while the near-IR colors and absolute magnitudes match those of the 5 Myr old L4 planetary-mass companion, 1RXS J160929.1-210524 b. Overall, CD-35 2722 B appears to be an intermediate-age benchmark for L dwarfs, with a less peaked H-band continuum than the youngest objects and near-IR absorption lines comparable to field objects. We fit Ames-Dusty model atmospheres to the near-IR spectra and find T eff= 1700-1900 K and log(g)= 4.5 ± 0.5. The spectra also show that the radial velocities of components A and B agree to within ±10 km s-1, further confirming their physical association. Using the age and bolometric luminosity of CD-35 2722 B, we derive a mass of 31 ± 8 M Jup from the Lyon/Dusty evolutionary models. Altogether, young late-M to mid-L type companions appear to be overluminous for their near-IR spectral type compared with field objects, in contrast to the underluminosity of young late-L and early-T dwarfs. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ci

  15. The plasma membrane of Leishmania donovani promastigotes is the main target for CA(1-8)M(1-18), a synthetic cecropin A-melittin hybrid peptide.

    PubMed Central

    Díaz-Achirica, P; Ubach, J; Guinea, A; Andreu, D; Rivas, L

    1998-01-01

    Reports on the lethal activity of animal antibiotic peptides have largely focused on bacterial rather than eukaryotic targets. In these, involvement of internal organelles as well as mechanisms different from those of prokaryotic cells have been described. CA(1-8)M(1-18) is a synthetic cecropin A-melittin hybrid peptide with leishmanicidal activity. Using Leishmania donovani promastigotes as a model system we have studied the mechanism of action of CA(1-8)M(1-18), its two parental peptides and two analogues. At micromolar concentration CA(1-8)M(1-18) induces a fast permeability to H+/OH-, collapse of membrane potential and morphological damage to the plasma membrane. Effects on other organelles are related to the loss of internal homeostasis of the parasite rather than to a direct effect of the peptide. Despite the fast kinetics of the process, the parasite is able to deactivate in part the effect of the peptide, as shown by the higher activity of the d-enantiomer of CA(1-8)M(1-18). Electrostatic interaction between the peptide and the promastigote membrane, the first event in the lethal sequence, is inhibited by polyanionic polysaccharides, including its own lipophosphoglycan. Thus, in common with bacteria, the action of CA(1-8)M(1-18) on Leishmania promastigotes has the same plasma membrane as target, but is unique in that different peptides show patterns of activity that resemble those observed on eukaryotic cells. PMID:9461543

  16. D-glucose derived novel gemini surfactants: synthesis and study of their surface properties, interaction with DNA, and cytotoxicity.

    PubMed

    Kumar, Vikash; Chatterjee, Amrita; Kumar, Nupur; Ganguly, Anasuya; Chakraborty, Indranil; Banerjee, Mainak

    2014-10-01

    Four new D-glucose derived m-s-m type gemini surfactants with variable spacer and tail length have been synthesized by a simple and efficient synthetic methodology utilizing the free C-3 hydroxy group of diisopropylidene glucose. The synthetic route to these gemini surfactants with a quaternary ammonium group as polar head group involves a sequence of simple reactions including alkylation, imine formation, quaternization of amine etc. The surface properties of the new geminis were evaluated by surface tension and conductivity measurements. These gemini surfactants showed low cytotoxicity by MTT assay on HeLa cell line. The DNA binding capabilities of these surfactants were determined by agarose gel electrophoresis, fluorescence titration, and DLS experiments. The preliminary studies by agarose gel electrophoresis indicated chain length dependent DNA binding abilities, further supported by ethidium bromide exclusion experiments. Two of the D-glucose derived gemini surfactants showed effective binding with pET-28a plasmid DNA (pDNA) at relatively low N/P ratio (i.e., cationic nitrogen/DNA phosphate molar ratio).

  17. Vesicles from pH-regulated reversible gemini amino-acid surfactants as nanocapsules for delivery.

    PubMed

    Lv, Jing; Qiao, Weihong; Li, Zongshi

    2016-10-01

    Reversible transition from micelles to vesicles by regulating pH were realized by gemini amino-acid surfactants N,N'-dialkyl-N,N'-diacetate ethylenediamine. Measurement results of ζ-potential at different pH and DLS at varying solvents revealed that the protonation between H(+) and double NCH2COO(-) groups (generating NH(+)CH2COO(-)), expressed as pKa1 and pKa2, is the key driving force to control the aggregation behaviors of gemini surfactant molecule. Effect of pH on the bilayer structure was studied in detail by using steady-state fluorescence spectroscopy of hydrophobic pyrene and Coumarin 153 (C153) respectively and fluorescence resonance energy transfer (FRET) from C153 to Rhodamine 6G (R6G). Various pH-regulated and pH-reversible self-assemblies were obtained in one surfactant system. Vitamin D3 was encapsulated in vesicle bilayers to form nano-VD3-capsules as VD3 supplement agent for health care products. By using the electrostatic attraction between Ca(2+) and double -COO(-) groups, nano-VD3-capsules with Ca(2+) coated outermost layers were prepared as a formulation for VD3 and calcium co-supplement agent. DLS and TEM were performed to check stability and morphology of the nano-capsules. It is concluded that the pH-regulated gemini amino-acid surfactants can be used to construct colloidal systems for delivering hydrophobic drugs or nutritions without lipids at human physiological pH level. PMID:27419647

  18. The interactions between cationic cellulose and Gemini surfactant in aqueous solution.

    PubMed

    Zhao, Shaojing; Cheng, Fa; Chen, Yu; Wei, Yuping

    2016-05-01

    Due to the extensive application of cationic cellulose in cosmetic, drug delivery and gene therapy, combining the improvement effect of surfactant-cellulose complexes, to investigate the properties of cellulose in aqueous solution is an important topic from both scientific and technical views. In this study, the phase behavior, solution properties and microstructure of Gemini surfactant sodium 5-nonyl-2-(4-(4-nonyl-2-sulfonatophenoxy)butoxy)phenyl sulfite (9-4-9)/cationic cellulose (JR400, the ammonium groups are directly bonded to the hydroxyethyl substituent with a degree substitution of 0.37) mixture was investigated using turbidity, fluorescence spectrophotometer and shear rheology techniques. As a control, the interaction of corresponding monovalent surfactant, sodium 2-ethoxy-5-nonylbenzenesulfonate (9-2) with JR400 in aqueous solution was also studied. Experimental results showed that 9-4-9/JR400 mixture has lower critical aggregation concentration (CAC) and critical micelle concentration (CMC) (about one order of magnitude) than 9-2/JR400 mixture. A low concentration of Gemini surfactant 9-4-9 appeared to induce an obvious micropolarity and viscosity value variation of the mixture, while these effects required a high concentration of corresponding monovalent one. Furthermore, dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements illuminated the formation and collapse procedure of network structure of the 9-4-9/JR400 mixture, which resulted in the increase and decrease of viscosity. These results suggest that the molecular structure of the surfactant has a great effect on its interaction with cationic cellulose. Moreover, the Gemini surfactant/cationic cellulose mixture may be used as a potencial stimuli-responsive drug delivery vector which not only load hydrophilic drugs, but also deliver hydrophobic substances. PMID:26876997

  19. Vesicles from pH-regulated reversible gemini amino-acid surfactants as nanocapsules for delivery.

    PubMed

    Lv, Jing; Qiao, Weihong; Li, Zongshi

    2016-10-01

    Reversible transition from micelles to vesicles by regulating pH were realized by gemini amino-acid surfactants N,N'-dialkyl-N,N'-diacetate ethylenediamine. Measurement results of ζ-potential at different pH and DLS at varying solvents revealed that the protonation between H(+) and double NCH2COO(-) groups (generating NH(+)CH2COO(-)), expressed as pKa1 and pKa2, is the key driving force to control the aggregation behaviors of gemini surfactant molecule. Effect of pH on the bilayer structure was studied in detail by using steady-state fluorescence spectroscopy of hydrophobic pyrene and Coumarin 153 (C153) respectively and fluorescence resonance energy transfer (FRET) from C153 to Rhodamine 6G (R6G). Various pH-regulated and pH-reversible self-assemblies were obtained in one surfactant system. Vitamin D3 was encapsulated in vesicle bilayers to form nano-VD3-capsules as VD3 supplement agent for health care products. By using the electrostatic attraction between Ca(2+) and double -COO(-) groups, nano-VD3-capsules with Ca(2+) coated outermost layers were prepared as a formulation for VD3 and calcium co-supplement agent. DLS and TEM were performed to check stability and morphology of the nano-capsules. It is concluded that the pH-regulated gemini amino-acid surfactants can be used to construct colloidal systems for delivering hydrophobic drugs or nutritions without lipids at human physiological pH level.

  20. New ester based gemini surfactants: the effect of different cationic headgroups on micellization properties and viscosity of aqueous micellar solution.

    PubMed

    Bhadani, Avinash; Tani, Misako; Endo, Takeshi; Sakai, Kenichi; Abe, Masahiko; Sakai, Hideki

    2015-07-15

    A new series of ester functionalized cationic gemini surfactants having different cationic headgroups (i.e. piperidinium, pyrrolidinium, morpholinium and quaternary ammonium) have been synthesized and characterized using NMR and Mass spectroscopy. These new gemini surfactants were investigated for their micellization and viscosity properties using surface tension, conductivity, fluorescence and rheology thechniques. The physicochemical properties of the aqueous surfactant system were influenced by polarity, size and the nature of cationic headgroups as the surface, thermodynamic and viscosity properties of these gemini surfactants were found to be dependent on the type of cationic headgroup. The current research finding establishes the structure-property relationship of the surfactant molecule specifically taking into account the dominant role displayed by the nature of the cationic headgroup. PMID:26145125

  1. Gemini: A hybrid plasma modelling capability for low pressure systems. User`s manual - V.1.7

    SciTech Connect

    Johannes, J.; Bartel, T.; Sears, D.; Payne, J.

    1996-10-01

    Gemini is the coupling of Icarus, the Sandia National Laboratories (SNL) 2-D Direct Simulation Monte Carlo (DMSC) code, to MPRES, the University of Houston 2-D finite element plasma reactor code. Thus, Gemini is not a stand alone code. The primary application of Gemini is the simulation of inductively coupled plasma reactors that operate at low pressures (< 10mtorr) where continuum formulations of the transport equations begin to break down. Plasma parameters (electron density (ne), electron temperature (Te) and electrostatic fields (Er and Ez)) are computed in MPRES and interpolated onto the DSMC grid. This allows transport of the neutrals and ions to be performed using the DSMC method while including electron impact reactions and field transport effects. A sample calculation including appropriate input files is given.

  2. The use of a high-order MEMS deformable mirror in the Gemini Planet Imager

    SciTech Connect

    Poyneer, L A; Bauman, B; Cornelissen, S; Jones, S; Macintosh, B; Palmer, D; Isaacs, J

    2010-12-17

    We briefly review the development history of the Gemini Planet Imager's 4K Boston Micromachines MEMS deformable mirror. We discuss essential calibration steps and algorithms to control the MEMS with nanometer precision, including voltage-phase calibration and influence function characterization. We discuss the integration of the MEMS into GPI's Adaptive Optics system at Lawrence Livermore and present experimental results of 1.5 kHz closed-loop control. We detail mitigation strategies in the coronagraph to reduce the impact of abnormal actuators on final image contrast.

  3. Comparación fotométrica en imágenes Gemini/GMOS:

    NASA Astrophysics Data System (ADS)

    Escudero, C. G.; Sesto, L. A.; González, N. M.; Faifer, F. R.; Smith Castelli, A.; Forte, J. C.

    2015-08-01

    We compare the performance and reliability of PSFEx and daophot ii in the construction and modeling of the Point Spread Function (PSF) on real images. Both methods were applied over photometric catalogs of globular cluster candidates in the elliptical galaxy NGC1395, generated with SExtractor on Gemini/GMOS images in the filters,,,. We use the PSF photometry obtained from both softwares to compare magnitudes, colour-colour and colour-magnitude diagrams. We also analyzed the new parameter spreadmodel used by SExtractor+PSFEx, which allows to separate point sources from extended objects.

  4. Implementation of modal combination rules for response spectrum analysis using GEMINI

    SciTech Connect

    Nukala, P K

    1999-06-01

    One of the widely used methodologies for describing the behavior of a structural system subjected to seismic excitation is response spectrum modal dynamic analysis. Several modal combination rules are proposed in the literature to combine the responses of individual modes in a response spectrum dynamic analysis. In particular, these modal combination rules are used to estimate the representative maximum value of a particular response of interest for design purposes. Furthermore, these combination rules also provide guidelines for combining the representative maximum values of the response obtained for each of the three orthogonal spatial components of an earthquake. This report mainly focuses on the implementation of different modal combination rules into GEMINI [I].

  5. Draft Genome Sequence of Aeribacillus pallidus Strain 8m3, a Thermophilic Hydrocarbon-Oxidizing Bacterium Isolated from the Dagang Oil Field (China)

    PubMed Central

    Poltaraus, Andrey B.; Sokolova, Diyana S.; Grouzdev, Denis S.; Ivanov, Timophey M.; Malakho, Sophia G.; Korshunova, Alena V.; Rozanov, Aleksey S.; Tourova, Tatiyana P.

    2016-01-01

    The draft genome sequence of Aeribacillus pallidus strain 8m3, a thermophilic aerobic oil-oxidizing bacterium isolated from production water from the Dagang high-temperature oil field, China, is presented here. The genome is annotated to provide insights into the genomic and phenotypic diversity of the genus Aeribacillus. PMID:27284131

  6. Role of spacer length in interaction between novel gemini imidazolium surfactants and Rhizopus oryzae lipase.

    PubMed

    Adak, Sunita; Datta, Sougata; Bhattacharya, Santanu; Banerjee, Rintu

    2015-11-01

    An insight into the effects of new ionic liquid-type gemini imidazolium cationic surfactants on the structure and function of the lipases is of prime importance for their potential application. Changes in the activity, stability and structure of Rhizopus oryzae lipase in the presence of novel gemini surfactants, [C16-3-C16im]Br2 and [C16-12-C16im]Br2 were probed in the present study. Surfactant with shorter spacer length, [C16-3-C16im]Br2 was found to be better in improving the hydrolytic activity and thermal stability of the lipase. For both the surfactants, activation was concentration dependent. CD spectroscopy results showed a decrease in α-helix and an increase in β-sheet content in the presence of these surfactants. A higher structural change observed in presence of [C16-12-C16im]Br2 correlated with lower enzyme activity. Isothermal titration calorimetric studies showed the binding to be spontaneous in nature based on sequential two site binding model. The forces involved in binding were found to differ for the two surfactants proving that the spacer length is an important factor which governs the interaction. These surfactants could be used as promising components both in enzyme modification and media engineering for attaining the desired goals in biocatalytic reactions.

  7. Solubilization of two organic dyes by cationic ester-containing gemini surfactants.

    PubMed

    Tehrani-Bagha, A R; Singh, R G; Holmberg, K

    2012-06-15

    Solubilization of two different types of organic dyes, Quinizarin with an anthraquinone structure and Sudan I with an azo structure, has been studied in aqueous solutions of a series of cationic gemini surfactants and of a conventional monomeric cationic surfactant, dodecyltrimethylammonium bromide (DTAB). Surfactant concentrations both above and below the critical micelle concentration were used. The concentration of solubilized dye at equilibrium was determined from the absorbance of the solution at λ(max) with the aid of a calibration curve. The solubilization power of the gemini surfactants was higher than that of DTAB and increased with increasing alkyl chain length. An increase in length of the spacer unit resulted in increased solubilization power while a hydroxyl group in the spacer did not have much effect. Ester bonds in the alkyl chains reduced the solubilization power with respect to both dyes. A comparison between the absorbance spectra of the dyes in micellar solution with spectra in a range of solvents of different polarity indicated that the dye is situated in a relatively polar environment. One may therefore assume that the dye is located just below the head group region of the micelle. Attractive π-cation interactions may play a role for orienting the dye to the outer region of the micelle.

  8. Gemini Planet Imager observational calibrations I: Overview of the GPI data reduction pipeline

    NASA Astrophysics Data System (ADS)

    Perrin, Marshall D.; Maire, Jérôme; Ingraham, Patrick; Savransky, Dmitry; Millar-Blanchaer, Max; Wolff, Schuyler G.; Ruffio, Jean-Baptiste; Wang, Jason J.; Draper, Zachary H.; Sadakuni, Naru; Marois, Christian; Rajan, Abhijith; Fitzgerald, Michael P.; Macintosh, Bruce; Graham, James R.; Doyon, René; Larkin, James E.; Chilcote, Jeffrey K.; Goodsell, Stephen J.; Palmer, David W.; Labrie, Kathleen; Beaulieu, Mathilde; De Rosa, Robert J.; Greenbaum, Alexandra Z.; Hartung, Markus; Hibon, Pascale; Konopacky, Quinn; Lafreniere, David; Lavigne, Jean-Francois; Marchis, Franck; Patience, Jenny; Pueyo, Laurent; Rantakyrö, Fredrik T.; Soummer, Rémi; Sivaramakrishnan, Anand; Thomas, Sandrine; Ward-Duong, Kimberly; Wiktorowicz, Sloane

    2014-07-01

    The Gemini Planet Imager (GPI) has as its science instrument an infrared integral field spectrograph/polarimeter (IFS). Integral field spectrographs are scientificially powerful but require sophisticated data reduction systems. For GPI to achieve its scientific goals of exoplanet and disk characterization, IFS data must be reconstructed into high quality astrometrically and photometrically accurate datacubes in both spectral and polarization modes, via flexible software that is usable by the broad Gemini community. The data reduction pipeline developed by the GPI instrument team to meet these needs is now publicly available following GPI's commissioning. This paper, the first of a series, provides a broad overview of GPI data reduction, summarizes key steps, and presents the overall software framework and implementation. Subsequent papers describe in more detail the algorithms necessary for calibrating GPI data. The GPI data reduction pipeline is open source, available from planetimager.org, and will continue to be enhanced throughout the life of the instrument. It implements an extensive suite of task primitives that can be assembled into reduction recipes to produce calibrated datasets ready for scientific analysis. Angular, spectral, and polarimetric differential imaging are supported. Graphical tools automate the production and editing of recipes, an integrated calibration database manages reference files, and an interactive data viewer customized for high contrast imaging allows for exploration and manipulation of data.

  9. Performance of the integral field spectrograph for the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Chilcote, Jeffrey K.; Larkin, James E.; Maire, Jérôme; Perrin, Marshall D.; Fitzgerald, Michael P.; Doyon, René; Thibault, Simon; Bauman, Brian; Macintosh, Bruce A.; Graham, James R.; Saddlemyer, Les

    2012-09-01

    We present performance results, from in-lab testing, of the Integral Field Spectrograph (IFS) for the Gemini Planet Imager (GPI). GPI is a facility class instrument for the Gemini Observatory with the primary goal of directly detecting young Jovian planets. The GPI IFS is based on concepts from the OSIRIS instrument at Keck and utilizes an infrared transmissive lenslet array to sample a rectangular 2.8 x 2.8 arcsecond field of view. The IFS provides low-resolution spectra across five bands between 1 and 2.5μm. Alternatively, the dispersing element can be replaced with a Wollaston prism to provide broadband polarimetry across the same five filter bands. The IFS construction was based at the University of California, Los Angeles in collaboration with the Université de Montr eal, Immervision and Lawrence Livermore National Laboratory. During its construction, we encountered an unusual noise source from microphonic pickup by the Hawaii-2RG detector. We describe this noise and how we eliminated it through vibration isolation. The IFS has passed its preship review and was shipped to University of California, Santa Cruz at the end of 2011 for integration with the remaining sub-systems of GPI. The IFS has been integrated with the rest of GPI and is delivering high quality spectral datacubes of GPI's coronagraphic field.

  10. GeMini: The Next-Generation Mechanically-Cooled Germanium Spectrometer

    SciTech Connect

    Burks, M

    2008-11-12

    The next-generation mechanically-cooled germanium spectrometer has been developed. GeMini (MINIature GErmanium spectrometer) has been designed to bring high-resolution gamma-ray spectroscopy to a range of demanding field environments. Intended applications include short-notice inspections, border patrol, port monitoring and emergency response, where positive nuclide identification of radioactive materials is required but power and liquid cryogen are not easily available. GeMini weighs 2.75 kg for the basic instrument and 4.5 kg for the full instrument including user interface and ruggedized hermetic packaging. It is very low power allowing it to operate for 10 hours on a single set of rechargeable batteries. This instrument employs technology adapted from the gamma-ray spectrometer currently flying on NASA's Mercury MESSENGER spacecraft. Specifically, infrared shielding techniques allow for a vast reduction of thermal load. This in turn allows for a smaller, lighter-weight design, well-suited for a hand-held instrument. Three working prototypes have been built and tested in the lab. The measured energy resolution is 3 keV fwhm at 662 keV gamma-rays. This paper will focus on the design and performance of the instrument.

  11. Binding behaviors of p-sulfonatocalix[4]arene with gemini guests.

    PubMed

    Zhao, Hong-Xia; Guo, Dong-Sheng; Liu, Yu

    2013-02-14

    A dozen of homoditopic cations, possessing different spacer lengths and rigidities, as well as sizes, shapes, and charges of terminal groups, were synthesized as candidate gemini guests for the complexation of p-sulfonatocalix[4]arenes (SC4A). The 12 gemini guests are divided into five species according to the different terminal groups: imidazolium (G1-G3), pyridinium (G4-G6), quinolinium (G7), viologen (G8-G11), and 1,4-diazabicyclo[2.2.2]octane (DBO, G12). Their binding structures and stoichiometries with SC4A were examined by NMR spectroscopy, which is helpful to construct diverse highly ordered assemblies. The obtained results show that the length of the linkers, as well as the charge numbers on the end groups have a pronounced effect on the binding stoichiometry, whereas the size and shape of the terminal groups have no significant influence. Furthermore, both the stability constants and thermodynamic parameters of SC4A with the terminal subunits were determined by the isothermal titration calorimetry experiments, which are valuable to understand the binding behavior, giving quantitatively deep insight.

  12. Interaction of a biosurfactant, Surfactin with a cationic Gemini surfactant in aqueous solution.

    PubMed

    Jin, Lei; Garamus, Vasil M; Liu, Fang; Xiao, Jingwen; Eckerlebe, Helmut; Willumeit-Römer, Regine; Mu, Bozhong; Zou, Aihua

    2016-11-01

    The interaction between biosurfactant Surfactin and cationic Gemini surfactant ethanediyl-1,3-bis(dodecyldimethylammonium bromide) (abbreviated as 12-3-12) was investigated using turbidity, surface tension, dynamic light scattering (DLS) and small angle neutron scattering (SANS). Analysis of critical micelle concentration (CMC) values in Surfactin/12-3-12 mixture indicates that there is synergism in formation of mixed Surfactin/12-3-12 micelles. Although Surfactin and 12-3-12 are oppositely charged in phosphate buffer solution (PBS, pH7.4), there are no precipitates observed at the concentrations below the CMC of Surfactin/12-3-12 system. However, at the concentration above CMC value, the Surfactin/12-3-12 mixture is severely turbid with high 12-3-12 content. DLS and SANS measurements follow the size and shape changes of mixed Surfactin/12-3-12 aggregates from small spherical micelles via elongated aggregates to large bulk complexes with increasing fraction of Gemini surfactant. PMID:27475707

  13. Synthesis and surface activities of a novel di-hydroxyl-sulfate-betaine-type zwitterionic gemini surfactants

    NASA Astrophysics Data System (ADS)

    Geng, Xiang F.; Hu, Xing Q.; Xia, Ji J.; Jia, Xue C.

    2013-04-01

    A series of novel di-hydroxyl-sulfate-betaine-type zwitterionic gemini surfactants of 1,2-bis[N-ethyl-N-(2-hydroxyl-3-sulfopropyl)-alkylammonium] alkyl betaines (DBAs-n, where s and n represent the spacer length of 2, 4 and 6 and the hydrocarbon chain length of 8, 12, 14, 16 and 18, respectively) were synthesized by reacting alkylamine with sodium 3-chloro-2-hydroxypropanesulfonate (the alternative sulphonated agent), followed by the reactions with а,ω-dibromoalkyl and then ethyl bromide. Their adsorption and aggregation properties were investigated by means of equilibrium surface tension, dynamic light-scattering (DLS) and transmission electron microscopy (TEM). DBAs-n gemini surfactants showed excellent surface activities and packed tightly at the interface. For example, the minimum CMC value for DBAs-n series was of the order of 10-5 M and the surface tension of water can be decreased as low as 22.2 mN/m. It was also found that the aggregates of DBAs-n solutions were significantly dependent on their hydrocarbon chain lengths. The aggregates changed from vesicles to entangled fiber-like micelles as the chain length increased from dodecyl to tetradecyl.

  14. Synthesis and properties of a lacquer wax-based quarternary ammonium gemini surfactant.

    PubMed

    Chen, Hongxia; Wang, Chengzhang; Ye, Jianzhong; Zhou, Hao; Lu, Li; Yang, Zhibing

    2014-03-24

    Lacquer wax is an important fatty resource obtained from the mesocarp of the berries of Toxicodendron vernicifluum. In order to expand the applications of lacquer wax, we hydrolyzed it after establishing the best conditions for the acid-catalyzed hydrolysis using a Box-Behnken design. Then we synthesized a quarternary ammonium gemini surfactant by a three-step reaction. The surface properties of an aqueous solution of the final product were investigated. The optimum conditions were 9% catalyst, 100 °C of reaction temperature and 14 h of reaction time, while the maximum free fatty acids (FFA)% was 99.67%. From the gas chromatography, the main fatty acids of the lacquer wax were palmitic, oleic and octadecanoic acid. The lacquer wax gemini surfactant was synthesized, and its structure was confirmed by IR and NMR. The experiments showed that the critical micelle concentration (CMC) is 5 × 10⁻⁴ mol·L⁻¹, the surface tension is 33.6 mN·m⁻¹. When the content of surfactant was 0.1%, the separation time of 5 mL water was 10 min.

  15. The AAO's Gemini High-Resolution Optical SpecTrograph (GHOST) concept

    NASA Astrophysics Data System (ADS)

    Ireland, Michael J.; Barnes, Stuart; Cochrane, David; Colless, Matthew; Connor, Peter; Horton, Anthony; Gibson, Steve; Lawrence, Jon; Martell, Sarah; McGregor, Peter; Nicolle, Tom; Nield, Kathryn; Orr, David; Robertson, J. G.; Ryder, Stuart; Sheinis, Andrew; Smith, Greg; Staszak, Nick; Tims, Julia; Xavier, Pascal; Young, Peter; Zheng, Jessica

    2012-09-01

    The Gemini High-Resolution Optical SpecTrograph (GHOST) will fill an important gap in the current suite of Gemini instruments. We will describe the Australian Astronomical Observatory (AAO)-led concept for GHOST, which consists of a multi-object, compact, high-efficiency, fixed-format, fiber-fed design. The spectrograph itself is a four-arm variant of the asymmetric white-pupil echelle Kiwispec spectrograph, Kiwisped, produced by Industrial Research Ltd. This spectrograph has an R4 grating and a 100mm pupil, and separate cross-disperser and camera optics for each of the four arms, carefully optimized for their respective wavelength ranges. We feed this spectrograph with a miniature lensletbased IFU that sub-samples the seeing disk of a single object into 7 hexagonal sub-images, reformatting this into a slit with a second set of double microlenses at the spectrograph entrance with relatively little loss due to focal-ratio degradation. This reformatting enables high spectral resolution from a compact design that fits well within the relatively tight GHOST budget. We will describe our baseline 2-object R~50,000 design with full wavelength coverage from the ultraviolet to the silicon cutoff, as well as the high-resolution single-object R~75,000 mode.

  16. Removal of phenol from synthetic waste water using Gemini micellar-enhanced ultrafiltration (GMEUF).

    PubMed

    Zhang, Wenxiang; Huang, Guohe; Wei, Jia; Li, Huiqin; Zheng, Rubing; Zhou, Ya

    2012-10-15

    Comprehensive studies were conducted on the phenol wastewater ultrafiltration (UF) with the help of various concentrations of cationic Gemini surfactant (N1-dodecyl-N1,N1,N2,N2-tetramethyl-N2-octylethane-1,2-diaminium bromide, CG), conventional cationic surfactant (dodecyl trimethyl ammonium bromide, DTAB), anionic surfactant (sodium dodecyl sulfate, SDS) and nonionic surfactant ((dodecyloxy)polyethoxyethanol, Brij35). A flat sheet module with polyethersulfone (PES) membrane was employed in this investigation. The effects of feed concentration (phenol and surfactant) on the retention of phenol and surfactant, permeate flux and membrane fouling by micelles were evaluated. The distribution coefficient (D), the loading of the micelles (L(m)) and the equilibrium distribution constant (K) were also utilized to estimate the micellar-enhanced ultrafiltration ability for phenol. Scanning electron microscope (SEM), Fourier transform infrared spectrometer with attenuated total reflectance accessory (ATR-FTIR) and mercury porosimeter were applied to analyze membrane surface morphology, membrane material characteristics and membrane fouling for the original and fouled membranes. Based on the above analysis, the performance of the selected Gemini surfactant was proved superior in the following aspects: retention of phenol/surfactant (peak value is 95.8% for phenol retention), permeate flux and membrane fouling with respect to other conventional surfactants possessing equal alkyl chain length. These results demonstrated that CG surfactant with exceptional structure has favorable prospects in the treatment of phenol wastewater by the micellar-enhanced ultrafiltration.

  17. Gemini planet imager observational calibrations IV: wavelength calibration and flexure correction for the integral field spectograph

    NASA Astrophysics Data System (ADS)

    Wolff, Schuyler G.; Perrin, Marshall D.; Maire, Jérôme; Ingraham, Patrick J.; Rantakyrö, Fredrik T.; Hibon, Pascale

    2014-08-01

    We present the wavelength calibration for the lenslet-based Integral Field Spectrograph (IFS) that serves as the science instrument for the Gemini Planet Imager (GPI). The GPI IFS features a 2.7" x 2.7" field of view and a 190 x 190 lenslet array (14.3 mas/lenslet) operating in Y, J, H, and K bands with spectral resolving power ranging from R ~ 35 to 78. Due to variations across the field of view, a unique wavelength solution is determined for each lenslet characterized by a two-dimensional position, the spectral dispersion, and the rotation of the spectrum with respect to the detector axes. The four free parameters are fit using a constrained Levenberg-Marquardt least-squares minimization algorithm, which compares an individual lenslet's arc lamp spectrum to a simulated arc lamp spectrum. This method enables measurement of spectral positions to better than 1/10th of a pixel on the GPI IFS detector using Gemini's facility calibration lamp unit GCAL, improving spectral extraction accuracy compared to earlier approaches. Using such wavelength calibrations we have measured how internal flexure of the spectrograph with changing zenith angle shifts spectra on the detector. We describe the methods used to compensate for these shifts when assembling datacubes from on-sky observations using GPI.

  18. Mode changes associated with oil droplet movement in solutions of gemini cationic surfactants.

    PubMed

    Banno, Taisuke; Miura, Shingo; Kuroha, Rie; Toyota, Taro

    2013-06-25

    Micrometer-sized self-propelled oil droplets in nonequilibrium systems have attracted much attention, since they form stable emulsions composed of oil, water, and surfactant which represent a primitive type of inanimate chemical machinery. In this work, we examined means of controlling the movement of oil droplets by studying the dynamics of n-heptyloxybenzaldehyde droplets in phosphate buffers containing alkanediyl-α,ω-bis(N-dodecyl-N,N-dimethylammonium bromide) (nG12) with either tetramethylene (4G12), octaethylene (8G12), or dodecamethylene (12G12) chains in the linker moiety. Significant differences in droplet dynamics were observed to be induced by changes in the linker structure of these gemini cationic surfactants. In a phosphate buffer containing 30 mM 4G12, self-propelled motion of droplets concurrent with the formation of molecular aggregates on their surfaces was observed, whereas the fusion of oil droplets was evident in both 8G12 and 12G12 solutions. We also determined that the surface activities and the extent of molecular self-assembly of the surfactants in phosphate buffer were strongly influenced by the alkyl chain length in the linker moiety. We therefore conclude that the surface activities of the gemini cationic surfactant have important effects on the oil-water interfacial tension of oil droplets and the formation of molecular aggregates and that both of these factors induce the unique movement of the droplets.

  19. Experimenting with Synthesis and Analysis of Cationic Gemini Surfactants in a Second-Semester General Chemistry Laboratory

    ERIC Educational Resources Information Center

    Anzovino, Mary E.; Greenberg, Andrew E.; Moore, John W.

    2015-01-01

    A laboratory experiment is described in which students synthesize a variety of cationic gemini surfactants and analyze their efficacy as fabric softeners. Students perform a simple organic synthesis reaction and two analytical tests (one qualitative and one quantitative), and use the class data to assess the synthesized products. The experiment…

  20. Interactions of bovine serum albumin with cationic imidazolium and quaternary ammonium gemini surfactants: effects of surfactant architecture.

    PubMed

    Zhou, Ting; Ao, Mingqi; Xu, Guiying; Liu, Teng; Zhang, Juan

    2013-01-01

    The interactions of BSA with a series of cationic imidazolium gemini surfactants ([C(n)-s-C(n)im]Br(2), n=10, 12, 14, s=2, 4, 6), quaternary ammonium surfactants (C(12)C(2)C(12)), and their corresponding monomers ([C(12)mim]Br and DTAB) are investigated by fluorescence using pyrene as a molecular probe, synchronous fluorescence, circular dichroism (CD), and UV-visible absorption spectra. These surfactants are used to elucidate the effects of surfactant hydrophilic head group, spacer length, and hydrophobic chain length on the conformation of BSA. The results of fluorescence spectra and CD show that the imidazolium gemini surfactants with shorter spacers or with longer hydrophobic chains have a larger effect on BSA unfolding, and the imidazolium gemini surfactant interacts with BSA more strongly than its corresponding monomer and the quaternary ammonium gemini surfactant. These conclusions have been confirmed by the binding constants (K(a)) and binding sites (n) for the BSA/surfactant system. Stern-Volmer quenching constants K(SV) of cationic surfactants binding to BSA are obtained, indicating that the probable quenching mechanism is initiated by ground-state complex formation rather than by dynamic collision. Moreover, the synchronous fluorescence spectra show that the surfactants mainly interact with tryptophan residues of BSA.

  1. 78 FR 40541 - GDT Tek, Inc., Gemini Explorations, Inc., Genetic Vectors, Inc., and Global Gate Property Corp...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-05

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION GDT Tek, Inc., Gemini Explorations, Inc., Genetic Vectors, Inc., and Global Gate Property Corp... accurate information concerning the securities of Genetic Vectors, Inc. because it has not filed...

  2. The influence of novel gemini surfactants containing cycloalkyl side-chains on the structural phases of DNA in solution.

    PubMed

    Pietralik, Zuzanna; Kumita, Janet R; Dobson, Christopher M; Kozak, Maciej

    2015-07-01

    Very important to gene therapy is the delivery system of the nucleic acids (called a vector), which will enhance the efficiency of the transport of new DNA into cells whilst protecting against damage. A promising alternative to the currently used viral vectors are the systems based on amphiphilic compounds - lipoplexes. Among them, gemini surfactants, which consist of two hydrophobic chains and two cationic heads connected by a linker - spacer group, appear to be promising candidates. The subject of this study involves two gemini surfactants, alkoxy derivatives of bis-imidazolium quaternary salts, differing in the length of their spacer groups and how they interact with two types of salmon sperm DNA (low and high molecular weight (MW)) or plasmid DNA (pDNA). The mixtures of gemini surfactants with nucleic acids of differing p/n ratios (positive-to-negative charge ratio) were characterised by small angle X-ray scattering (SAXS) of synchrotron radiation, dynamic light scattering (DLS), circular dichroism (CD) spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and gel electrophoresis techniques. This analysis allows for the selection of the most suitable and promising candidates for non-viral vectors in gene therapy, determination of the conditions needed to form stable complexes, identification of conformational changes in the DNA molecules upon interactions with gemini surfactants and in some cases, determination of the structures formed in these lipoplexes.

  3. Electrochemical bioplatforms for the simultaneous determination of interleukin (IL)-8 mRNA and IL-8 protein oral cancer biomarkers in raw saliva.

    PubMed

    Torrente-Rodríguez, R M; Campuzano, S; Ruiz-Valdepeñas Montiel, V; Gamella, M; Pingarrón, J M

    2016-03-15

    The development of electrochemical magnetobiosensors for the simultaneous determination of two biomarkers associated with salivary oral cancer, protein IL-8 and its messenger RNA (IL-8 mRNA) associated, in undiluted human saliva samples is reported in this work. The implemented methodology involves the use of functionalized magnetic beads, specific antibodies against IL-8 protein, a specific hairpin DNA sequence for IL-8 mRNA and amperometric detection at disposable dual screen printed carbon electrodes. This methodology exhibits high sensitivity and selectivity for the target analytes providing detection limits of 0.21 nM for IL-8 mRNA and 72.4 pgmL(-1) (far below the clinical established cut-off of 600 pgmL(-1)) for IL-8 protein in undiluted saliva samples. The dual amperometric magnetobiosensor was applied to the direct determination of both biomarkers in spiked raw saliva samples and to determine the endogenous content of IL-8 protein in saliva samples from 7 healthy individuals. The obtained results were statistically in agreement with those provided by a commercial ELISA kit.

  4. Near-infrared dust and line emission from the central region of Mrk1066: constraints from Gemini NIFS

    NASA Astrophysics Data System (ADS)

    Riffel, Rogemar A.; Storchi-Bergmann, Thaisa; Nagar, Neil M.

    2010-05-01

    We present integral field spectroscopy of the inner 700 × 700pc2 of the Seyfert galaxy Mrk1066 obtained with Gemini's Near-Infrared Integral Field Spectrograph (NIFS) at a spatial resolution of ~35pc. This high spatial resolution allowed us to observe, for the first time in this galaxy, an unresolved dust concentration with mass ~1.4 × 10-2Msolar. This unresolved concentration, with emission well reproduced by a blackbody with temperature ~830K, is possibly part of the nuclear dusty torus. We compared maps of emission-line flux distributions and ratios with a 3.6cm radio-continuum image and [OIII] image in order to investigate the origin of the near-infrared emission. The emission-line fluxes are elongated in PA = 135°/315° in agreement with the [OIII] and radio images and, except for the H lines, are brighter to the north-west than to the south-east. This close association with the radio hot spot implies that at least part of the emitting gas is co-spatial with the radio outflow. The H emission is stronger to the south-east, where we find a large region of star-formation. The strong correlation between the radio emission and the highest emission-line fluxes indicates that the radio jet plays a fundamental role at these intensity levels. At lower emission-line fluxes this correlation disappears suggesting a contribution from the plane of the galaxy to the observed emission. The H2 flux is more uniformly distributed and has an excitation temperature of ~2100K. Its origin appears to be circum-nuclear gas heated by X-rays from the central active nucleus. The [FeII] emission also is consistent with X-ray heating, but its spatial correlation with the radio jet and [OIII] emission indicates additional emission due to excitation and/or abundance changes caused by shocks in the radio jet. The coronal-line emission of [CaVIII] and [SIX] is unresolved by our observations indicating a distribution within 18pc from the nucleus. The reddening map obtained via the Pa

  5. SUBARU AND GEMINI OBSERVATIONS OF SS 433: NEW CONSTRAINT ON THE MASS OF THE COMPACT OBJECT

    SciTech Connect

    Kubota, K.; Ueda, Y.; Fabrika, S.; Barsukova, E. A.; Sholukhova, O.; Medvedev, A.; Goranskij, V. P.

    2010-02-01

    We present results of optical spectroscopic observations of the mass donor star in SS 433 with Subaru and Gemini, with an aim to best constrain the mass of the compact object. Subaru/Faint Object Camera and Spectrograph observations were performed on four nights of 2007 October 6-8 and 10, covering the orbital phase of phi = 0.96 - 0.26. We first calculate the cross-correlation function (CCF) of these spectra with that of the reference star HD 9233 in the wavelength range of 4740-4840 A. This region is selected to avoid 'strong' absorption lines accompanied with contaminating emission components, which most probably originate from the surroundings of the donor star, such as the wind and gas stream. The same analysis is applied to archive data of Gemini/GMOS taken at phi = 0.84 - 0.30 by Hillwig and Gies. From the Subaru and Gemini CCF results, the amplitude of the radial velocity curve of the donor star is determined to be 58.3 +- 3.8 km s{sup -1} with a systemic velocity of 59.2 +- 2.5 km s{sup -1}. Together with the radial velocity curve of the compact object, we derive the mass of the donor star and compact object to be M{sub O} = 12.4 +- 1.9 M{sub sun} and M{sub X} = 4.3 +- 0.6 M{sub sun}, respectively. We conclude, however, that these values should be taken as upper limits. From the analysis of the averaged absorption line profiles of strong lines (mostly ions) and weak lines (mostly neutrals) observed with Subaru, we find evidence for heating effects from the compact object. Using a simple model, we find that the true radial velocity amplitude of the donor star could be as low as 40 +- 5 km s{sup -1} in order to produce the observed absorption-line profiles. Taking into account the heating of the donor star may lower the derived masses to M{sub O} = 10.4{sup +2.3}{sub -1.9} M{sub sun} and M{sub X} = 2.5{sup +0.7}{sub -0.6} M{sub sun}. Our final constraint, 1.9 M{sub sun} <=M{sub X}<= 4.9 M{sub sun}, indicates that the compact object in SS 433 is most likely a

  6. Interaction of a green ester-bonded gemini surfactant with xanthine oxidase: Biophysical perspective.

    PubMed

    Akram, Mohd; Bhat, Imtiyaz Ahmad; Kabir-ud-Din

    2015-01-01

    A multi technique approach was utilized to explore the interaction between a novel green gemini surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-tetradecylammoniumacetoxy) dichloride (14-E2-14), with bovine milk xanthine oxidase (XO). Tensiometric, spectroscopic, microscopic and molecular modeling results demonstrate significant interaction and structural change of native xanthine oxidase upon 14-E2-14 combination. The results obtained in this study may be beneficial for scientists to calibrate conformation of the enzyme by novel biodegradable/green microstructures; consequently, it would likely add new impetus in understanding the treatment modes of various diseases like gout, hyperuricemia, liver and brain necrosis. Moreover, the 14-E2-14-XO interaction assists to unfurl new routes in the designing/selection of green-surfactant-protein mixtures widely used in food processing, cosmetics, and pharmaceutical industries.

  7. Interaction of a green ester-bonded gemini surfactant with xanthine oxidase: Biophysical perspective.

    PubMed

    Akram, Mohd; Bhat, Imtiyaz Ahmad; Kabir-ud-Din

    2015-01-01

    A multi technique approach was utilized to explore the interaction between a novel green gemini surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-tetradecylammoniumacetoxy) dichloride (14-E2-14), with bovine milk xanthine oxidase (XO). Tensiometric, spectroscopic, microscopic and molecular modeling results demonstrate significant interaction and structural change of native xanthine oxidase upon 14-E2-14 combination. The results obtained in this study may be beneficial for scientists to calibrate conformation of the enzyme by novel biodegradable/green microstructures; consequently, it would likely add new impetus in understanding the treatment modes of various diseases like gout, hyperuricemia, liver and brain necrosis. Moreover, the 14-E2-14-XO interaction assists to unfurl new routes in the designing/selection of green-surfactant-protein mixtures widely used in food processing, cosmetics, and pharmaceutical industries. PMID:25849998

  8. Effect of Gemini primary mirror position relative to the lateral support on mirror figure

    NASA Astrophysics Data System (ADS)

    Cho, Myung K.; Stepp, Larry M.

    2000-07-01

    The Gemini primary mirror support incorporates a system of hydraulic whiffletrees to carry the mirror weight and define its position. The six orthogonal kinematic degrees of freedom are controlled by six hydraulic zones--three axial, two lateral, plus a transverse lateral. By varying the fluid volumes in these hydraulic zones the mirror position can be adjusted in all six degrees of freedom. Because of the finite lengths of the linkages that connect the mirror to the lateral supports, any shift in mirror position changes the amplitudes and directions of the applied forces with a resulting effect on the static balance and mirror figure. These effects have been calculated for mirror translations and rotations in all six degrees of freedom, resulting in predictions of the changes in the axial and lateral support forces and in the mirror figure. This paper describes the modeling as well as experimental verification of the results.

  9. GEMINI PLANET IMAGER SPECTROSCOPY OF THE HR 8799 PLANETS c AND d

    SciTech Connect

    Ingraham, Patrick; Macintosh, Bruce; Marley, Mark S.; Saumon, Didier; Marois, Christian; Dunn, Jennifer; Erikson, Darren; Barman, Travis; Bauman, Brian; Burrows, Adam; Chilcote, Jeffrey K.; Fitzgerald, Michael P.; De Rosa, Robert J.; Dillon, Daren; Gavel, Donald; Doyon, René; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Graham, James R.; and others

    2014-10-10

    During the first-light run of the Gemini Planet Imager we obtained K-band spectra of exoplanets HR 8799 c and d. Analysis of the spectra indicates that planet d may be warmer than planet c. Comparisons to recent patchy cloud models and previously obtained observations over multiple wavelengths confirm that thick clouds combined with horizontal variation in the cloud cover generally reproduce the planets' spectral energy distributions. When combined with the 3 to 4 μm photometric data points, the observations provide strong constraints on the atmospheric methane content for both planets. The data also provide further evidence that future modeling efforts must include cloud opacity, possibly including cloud holes, disequilibrium chemistry, and super-solar metallicity.

  10. Discovery and spectroscopy of the young Jovian planet 51 Eri b with the Gemini Planet Imager

    DOE PAGES

    Macintosh, B.; Graham, J. R.; Barman, T.; De Rosa, R. J.; Konopacky, Q.; Marley, M. S.; Marois, C.; Nielsen, E. L.; Pueyo, L.; Rajan, A.; et al

    2015-10-02

    Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water-vapor absorption. Modeling of the spectra and photometry yields a luminosity (normalized by the luminosity of the Sun) of 1.6 to 4.0 × 10–6 and an effective temperature of 600 to 750 kelvin. For this age and luminosity, “hot-start” formation models indicate a mass twicemore » that of Jupiter. As a result, this planet also has a sufficiently low luminosity to be consistent with the “cold-start” core-accretion process that may have formed Jupiter.« less

  11. Gemini Planet Imager Spectroscopy of the HR 8799 Planets c and d

    DOE PAGES

    Ingraham, Patrick; Marley, Mark S.; Saumon, Didier; Marois, Christian; Macintosh, Bruce; Barman, Travis; Bauman, Brian; Burrows, Adam; Chilcote, Jeffrey K.; De Rosa, Robert J.; et al

    2014-09-30

    During the first-light run of the Gemini Planet Imager we obtained K-band spectra of exoplanets HR 8799 c and d. Analysis of the spectra indicates that planet d may be warmer than planet c. Comparisons to recent patchy cloud models and previously obtained observations over multiple wavelengths confirm that thick clouds combined with horizontal variation in the cloud cover generally reproduce the planets’ spectral energy distributions.When combined with the 3 to 4μm photometric data points, the observations provide strong constraints on the atmospheric methane content for both planets. Lastly, the data also provide further evidence that future modeling efforts mustmore » include cloud opacity, possibly including cloud holes, disequilibrium chemistry, and super-solar metallicity.« less

  12. The Gemini secondary mirror tip/tilt system: past, present, and future

    NASA Astrophysics Data System (ADS)

    Carter, Christopher J.; Rippa, Mathew J.; Rojas, Roberto; Sheehan, Michael P.

    2008-07-01

    The Gemini Observatory is currently in the early stages of a major upgrade of the Secondary Mirror Tip/tilt Systems (M2TS). Although these systems continue to deliver good fast-steering and chopping performance at both sites, there are persistent and occasionally time-consuming issues that need to be addressed in order for them to deliver their full potential and further reduce downtime. We present an overview of the system, outline its capabilities, and review the early commissioning process and some of the issues encountered. We describe the augmentation of the original system with data logging features which made possible some critical servo tuning work that was key in delivering improved performance. The hardware and software upgrade project to date is discussed, along with a brief overview of items it intends to address.

  13. Discovery and spectroscopy of the young jovian planet 51 Eri b with the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Macintosh, B.; Graham, J. R.; Barman, T.; De Rosa, R. J.; Konopacky, Q.; Marley, M. S.; Marois, C.; Nielsen, E. L.; Pueyo, L.; Rajan, A.; Rameau, J.; Saumon, D.; Wang, J. J.; Patience, J.; Ammons, M.; Arriaga, P.; Artigau, E.; Beckwith, S.; Brewster, J.; Bruzzone, S.; Bulger, J.; Burningham, B.; Burrows, A. S.; Chen, C.; Chiang, E.; Chilcote, J. K.; Dawson, R. I.; Dong, R.; Doyon, R.; Draper, Z. H.; Duchêne, G.; Esposito, T. M.; Fabrycky, D.; Fitzgerald, M. P.; Follette, K. B.; Fortney, J. J.; Gerard, B.; Goodsell, S.; Greenbaum, A. Z.; Hibon, P.; Hinkley, S.; Cotten, T. H.; Hung, L.-W.; Ingraham, P.; Johnson-Groh, M.; Kalas, P.; Lafreniere, D.; Larkin, J. E.; Lee, J.; Line, M.; Long, D.; Maire, J.; Marchis, F.; Matthews, B. C.; Max, C. E.; Metchev, S.; Millar-Blanchaer, M. A.; Mittal, T.; Morley, C. V.; Morzinski, K. M.; Murray-Clay, R.; Oppenheimer, R.; Palmer, D. W.; Patel, R.; Perrin, M. D.; Poyneer, L. A.; Rafikov, R. R.; Rantakyrö, F. T.; Rice, E. L.; Rojo, P.; Rudy, A. R.; Ruffio, J.-B.; Ruiz, M. T.; Sadakuni, N.; Saddlemyer, L.; Salama, M.; Savransky, D.; Schneider, A. C.; Sivaramakrishnan, A.; Song, I.; Soummer, R.; Thomas, S.; Vasisht, G.; Wallace, J. K.; Ward-Duong, K.; Wiktorowicz, S. J.; Wolff, S. G.; Zuckerman, B.

    2015-10-01

    Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water-vapor absorption. Modeling of the spectra and photometry yields a luminosity (normalized by the luminosity of the Sun) of 1.6 to 4.0 × 10-6 and an effective temperature of 600 to 750 kelvin. For this age and luminosity, “hot-start” formation models indicate a mass twice that of Jupiter. This planet also has a sufficiently low luminosity to be consistent with the “cold-start” core-accretion process that may have formed Jupiter.

  14. Discovery and spectroscopy of the young jovian planet 51 Eri b with the Gemini Planet Imager.

    PubMed

    Macintosh, B; Graham, J R; Barman, T; De Rosa, R J; Konopacky, Q; Marley, M S; Marois, C; Nielsen, E L; Pueyo, L; Rajan, A; Rameau, J; Saumon, D; Wang, J J; Patience, J; Ammons, M; Arriaga, P; Artigau, E; Beckwith, S; Brewster, J; Bruzzone, S; Bulger, J; Burningham, B; Burrows, A S; Chen, C; Chiang, E; Chilcote, J K; Dawson, R I; Dong, R; Doyon, R; Draper, Z H; Duchêne, G; Esposito, T M; Fabrycky, D; Fitzgerald, M P; Follette, K B; Fortney, J J; Gerard, B; Goodsell, S; Greenbaum, A Z; Hibon, P; Hinkley, S; Cotten, T H; Hung, L-W; Ingraham, P; Johnson-Groh, M; Kalas, P; Lafreniere, D; Larkin, J E; Lee, J; Line, M; Long, D; Maire, J; Marchis, F; Matthews, B C; Max, C E; Metchev, S; Millar-Blanchaer, M A; Mittal, T; Morley, C V; Morzinski, K M; Murray-Clay, R; Oppenheimer, R; Palmer, D W; Patel, R; Perrin, M D; Poyneer, L A; Rafikov, R R; Rantakyrö, F T; Rice, E L; Rojo, P; Rudy, A R; Ruffio, J-B; Ruiz, M T; Sadakuni, N; Saddlemyer, L; Salama, M; Savransky, D; Schneider, A C; Sivaramakrishnan, A; Song, I; Soummer, R; Thomas, S; Vasisht, G; Wallace, J K; Ward-Duong, K; Wiktorowicz, S J; Wolff, S G; Zuckerman, B

    2015-10-01

    Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water-vapor absorption. Modeling of the spectra and photometry yields a luminosity (normalized by the luminosity of the Sun) of 1.6 to 4.0 × 10(-6) and an effective temperature of 600 to 750 kelvin. For this age and luminosity, "hot-start" formation models indicate a mass twice that of Jupiter. This planet also has a sufficiently low luminosity to be consistent with the "cold-start" core-accretion process that may have formed Jupiter. PMID:26272904

  15. Discovery and spectroscopy of the young jovian planet 51 Eri b with the Gemini Planet Imager.

    PubMed

    Macintosh, B; Graham, J R; Barman, T; De Rosa, R J; Konopacky, Q; Marley, M S; Marois, C; Nielsen, E L; Pueyo, L; Rajan, A; Rameau, J; Saumon, D; Wang, J J; Patience, J; Ammons, M; Arriaga, P; Artigau, E; Beckwith, S; Brewster, J; Bruzzone, S; Bulger, J; Burningham, B; Burrows, A S; Chen, C; Chiang, E; Chilcote, J K; Dawson, R I; Dong, R; Doyon, R; Draper, Z H; Duchêne, G; Esposito, T M; Fabrycky, D; Fitzgerald, M P; Follette, K B; Fortney, J J; Gerard, B; Goodsell, S; Greenbaum, A Z; Hibon, P; Hinkley, S; Cotten, T H; Hung, L-W; Ingraham, P; Johnson-Groh, M; Kalas, P; Lafreniere, D; Larkin, J E; Lee, J; Line, M; Long, D; Maire, J; Marchis, F; Matthews, B C; Max, C E; Metchev, S; Millar-Blanchaer, M A; Mittal, T; Morley, C V; Morzinski, K M; Murray-Clay, R; Oppenheimer, R; Palmer, D W; Patel, R; Perrin, M D; Poyneer, L A; Rafikov, R R; Rantakyrö, F T; Rice, E L; Rojo, P; Rudy, A R; Ruffio, J-B; Ruiz, M T; Sadakuni, N; Saddlemyer, L; Salama, M; Savransky, D; Schneider, A C; Sivaramakrishnan, A; Song, I; Soummer, R; Thomas, S; Vasisht, G; Wallace, J K; Ward-Duong, K; Wiktorowicz, S J; Wolff, S G; Zuckerman, B

    2015-10-01

    Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water-vapor absorption. Modeling of the spectra and photometry yields a luminosity (normalized by the luminosity of the Sun) of 1.6 to 4.0 × 10(-6) and an effective temperature of 600 to 750 kelvin. For this age and luminosity, "hot-start" formation models indicate a mass twice that of Jupiter. This planet also has a sufficiently low luminosity to be consistent with the "cold-start" core-accretion process that may have formed Jupiter.

  16. Gemini H-band spectroscopy of the Galactic microquasar GRS 1915+105

    NASA Astrophysics Data System (ADS)

    McConnell, O.; Callanan, P.; Reynolds, M.

    2014-07-01

    Since its discovery in 1994 (Castro-Tirado 1994) GRS 1915+105 has become one of the most intensely studied of all the X-ray binaries in the Galaxy. This Galactic microquasar system is unique in that it has remained in outburst for the past 20 years: furthermore, initial measurements suggested a relatively high black hole mass of 14 ± 4 M_{⊙} (Greiner et al. 2001), outside the predicted mass range for such transients (Ozel et al. 2010). Here we present new Gemini H-band observations, and discuss the degree to which they can be used to refine the black hole mass in comparison to more recent estimates (Hurley et al 2013, Steeghs et al 2013). In addition, previous work found phase dependent emission of the CO bandheads in the K-band, and we present evidence of double peaked emission lines, indicative of ongoing mass transfer via the accretion disk.

  17. Direct observation of extrasolar planets and the development of the gemini planet imager integral field spectrograph

    NASA Astrophysics Data System (ADS)

    Chilcote, Jeffrey Kaplan

    This thesis is focused on the development and testing of a new instrument capable of finding and characterizing recently-formed Jupiter-sized planets orbiting other stars. To observe these planets, I present the design, construction and testing of the Gemini Planet Imager (GPI) Integral Field Spectrograph (IFS). GPI is a facility class instrument for the Gemini Observatory with the primary goal of directly detecting young Jovian planets. The GPI IFS utilizes an infrared transmissive lenslet array to sample a rectangular 2.7 x 2.7 arcsecond field of view and provide low-resolution spectra across five bands between 1 and 2.5 mum. The dispersing element can be replaced with a Wollaston prism to provide broadband polarimetry across the same five filter bands. The IFS construction was based at the University of California, Los Angeles in collaboration with the Universite de Montreal, Immervision and Lawrence Livermore National Laboratory. I will present performance results, from in-lab testing, of the Integral Field Spectrograph (IFS) for the Gemini Planet Imager (GPI). The IFS is a large, complex, cryogenic, optical system requiring several years of development and testing. I will present the design and integration of the mechanical and optical performance of the spectrograph optics. The IFS passed its pre-ship review in 2011 and was shipped to University of California, Santa Cruz for integration with the remaining sub-systems of GPI. The UCLA built GPI IFS was integrated with the rest of GPI and is delivering high quality spectral datacubes of GPI's coronagraphic field. Using the NIRC2 instrument located at the Keck Observatory, my collaborators and I observed the planetary companion to beta Pictoris in L' (3.5--4.1mum). Observations taken in the fall of 2009 and 2012 are used to find the location and inclination of the planet relative to the massive debris disk orbiting beta Pictoris. We find that the planet's orbit has a position angle on the sky of 211

  18. Discovery and spectroscopy of the young Jovian planet 51 Eri b with the Gemini Planet Imager

    SciTech Connect

    Macintosh, B.; Graham, J. R.; Barman, T.; De Rosa, R. J.; Konopacky, Q.; Marley, M. S.; Marois, C.; Nielsen, E. L.; Pueyo, L.; Rajan, A.; Rameau, J.; Saumon, D.; Wang, J. J.; Patience, J.; Ammons, M.; Arriaga, P.; Artigau, E.; Beckwith, S.; Brewster, J.; Bruzzone, S.; Bulger, J.; Burningham, B.; Burrows, A. S.; Chen, C.; Chiang, E.; Chilcote, J. K.; Dawson, R. I.; Dong, R.; Doyon, R.; Draper, Z. H.; Duchene, G.; Esposito, T. M.; Fabrycky, D.; Fitzgerald, M. P.; Follette, K. B.; Fortney, J. J.; Gerard, B.; Goodsell, S.; Greenbaum, A. Z.; Hibon, P.; Hinkley, S.; Cotten, T. H.; Hung, L. -W.; Ingraham, P.; Johnson-Groh, M.; Kalas, P.; Lafreniere, D.; Larkin, J. E.; Lee, J.; Line, M.; Long, D.; Maire, J.; Marchis, F.; Matthews, B. C.; Max, C. E.; Metchev, S.; Millar-Blanchaer, M. A.; Mittal, T.; Morley, C. V.; Morzinski, K. M.; Murray-Clay, R.; Oppenheimer, R.; Palmer, D. W.; Patel, R.; Perrin, M. D.; Poyneer, L. A.; Rafikov, R. R.; Rantakyro, F. T.; Rice, E. L.; Rojo, P.; Rudy, A. R.; Ruffio, J. -B.; Ruiz, M. T.; Sadakuni, N.; Saddlemyer, L.; Salama, M.; Savransky, D.; Schneider, A. C.; Sivaramakrishnan, A.; Song, I.; Soummer, R.; Thomas, S.; Vasisht, G.; Wallace, J. K.; Ward-Duong, K.; Wiktorowicz, S. J.; Wolff, S. G.; Zuckerman, B.

    2015-10-02

    Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water-vapor absorption. Modeling of the spectra and photometry yields a luminosity (normalized by the luminosity of the Sun) of 1.6 to 4.0 × 10–6 and an effective temperature of 600 to 750 kelvin. For this age and luminosity, “hot-start” formation models indicate a mass twice that of Jupiter. As a result, this planet also has a sufficiently low luminosity to be consistent with the “cold-start” core-accretion process that may have formed Jupiter.

  19. Gemini Planet Imager Spectroscopy of the HR 8799 Planets c and d

    SciTech Connect

    Ingraham, Patrick; Marley, Mark S.; Saumon, Didier; Marois, Christian; Macintosh, Bruce; Barman, Travis; Bauman, Brian; Burrows, Adam; Chilcote, Jeffrey K.; De Rosa, Robert J.; Dillon, Daren; Doyon, René; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P.; Gavel, Donald; Goodsell, Stephen J.; Graham, James R.; Hartung, Markus; Hibon, Pascale; Kalas, Paul G.; Konopacky, Quinn; Larkin, James A.; Marchis, Franck; McBride, James; Millar-Blanchaer, Max; Morzinski, Katie M.; Norton, Andrew; Oppenheimer, Rebecca; Palmer, Dave W.; Patience, Jenny; Perrin, Marshall D.; Poyneer, Lisa A.; Pueyo, Laurent; Rantakyrö, Fredrik; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Soummer, Rémi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Kent Wallace, J.; Wiktorowicz, Sloane J.; Wolff, Schuyler G.

    2014-09-30

    During the first-light run of the Gemini Planet Imager we obtained K-band spectra of exoplanets HR 8799 c and d. Analysis of the spectra indicates that planet d may be warmer than planet c. Comparisons to recent patchy cloud models and previously obtained observations over multiple wavelengths confirm that thick clouds combined with horizontal variation in the cloud cover generally reproduce the planets’ spectral energy distributions.When combined with the 3 to 4μm photometric data points, the observations provide strong constraints on the atmospheric methane content for both planets. Lastly, the data also provide further evidence that future modeling efforts must include cloud opacity, possibly including cloud holes, disequilibrium chemistry, and super-solar metallicity.

  20. Tracking Publications Based on Telescope Sharing among Gemini, Subaru, and Keck: An Update

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Tsang, E.; Kamisato, P.

    2015-04-01

    Gemini Observatory, Subaru Telescope, and Keck Observatory collectively operate five 8-10 meters telescopes on the summit of Mauna Kea on the Island of Hawaii and at Cerro Pachon in Chile. The three institutions began a telescope exchange program in 2005 to expand the range of backend instruments available to their respective users. A participating observatory's users can apply for telescope time from the other two observatories through the time exchange program. To measure the success of the program, we collected publications that resulted from the exchange program for the period from 2005 to 2013. Bibliometric analysis was performed on these publications to measure the productivity and impact of the exchange program. This is an enhanced and updated version of the paper presented at the IAU Commission 5 working Group Libraries session in Beijing, 2012.

  1. Observations of Rosetta Target (21) Lutetia with Keck and Gemini Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Conrad, A. R.; Merline, W. J.; Drummond, J.; Carry, B.; Tamblyn, P. M.; Chapman, C. R.; Dumas, C.; Weaver, H. A.

    2009-12-01

    In support of the NASA/ESA Rosetta mission’s plans to observe asteroid (21) Lutetia during a 2010 July flyby, and in conjunction with a larger ground-based plus HST campaign to support this mission, we observed Lutetia from Keck and Gemini-North during several nights spanning 2008 Oct through 2009 Jan. Observations were made using adaptive optics in the near-IR, primarily at K-band (2.1 micron), and were timed to coincide with the asteroid's most recent opposition at a distance of about 1.4 AU. From these data, we determined Lutetia’s triaxial size and shape to be 132 x 101 x 76 km, with maximum expected uncertainties of 4 x 3 x 31 km. The spin pole is found to be at (RA, Dec) = (48, +9) deg or ecliptic (long, lat) = (49,-8) deg, with a formal uncertainty radius (not including systematics) of 3 deg. We have calibrated our technique of deriving dimensions of asteroids from AO images against Pluto and 4 satellites of Saturn with accurate diameters, and we expect that our systematics (included in the size uncertainties above) are no more than 3%. We also searched for satellites and our preliminary results indicate no detection of a satellite larger than about 1 km over a significant fraction of the Hill sphere (10-240 asteroid radii). Improved limits are expected from a more refined analysis. We are grateful for telescope time made available to us by S. Kulkarni and M. Busch (Cal Tech) for a portion of this dataset. We also thank our collaborators on Team Keck, the Keck science staff, for making possible some of these observations and for observing time granted at Gemini under NOAO time allocation. Plane-of-sky short and long axes of (21) Lutetia taken from Keck AO images on 2008 Dec 2.

  2. Monomeric and gemini surfactants as antimicrobial agents - influence on environmental and reference strains.

    PubMed

    Koziróg, Anna; Brycki, Bogumił

    2015-01-01

    Quaternary ammonium salts (QAS) belong to surfactant commonly used both, in the household and in different branches of industry, primarily in the process of cleaning and disinfection. They have several positive features inter alia effectively limiting the development of microorganisms on many surfaces. In the present work, two compounds were used as biocides: hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) that belongs to the gemini surfactant (GS), and its single analogue - dodecyl(trimethyl)ammonium bromide (DTAB). Two fold dilution method was used to determine the minimum concentration of compounds (MIC) which inhibit the growth of bacteria: Staphylococcus aureus (ATCC 6538 and an environmental strain), Pseudomonas aeruginosa (ATCC 85327 and an environmental strain), and yeast Candida albicans (ATCC 11509 and an environmental strain). The viability of cells in liquid cultures with addition of these substances at ¼ MIC, ½ MIC and MIC concentrations were also determined. The obtained results show that DTAB inhibits the growth of bacteria at the concentration of 0.126-1.010 µM/ml, and gemini surfactant is active at 0.036-0.029 µM/ml. Therefore, GS is active at more than 17-70-fold lower concentrations than its monomeric analogue. Strains isolated from natural environment are less sensitive upon testing biocides than the references strains. Both compounds at the MIC value reduced the number of cells of all strains. The use of too low concentration of biocides can limit the growth of microorganisms, but often only for a short period of time in case of special environmental strains. Later on, they can adapt to adverse environmental conditions and begin to evolve defence mechanisms.

  3. Monomeric and gemini surfactants as antimicrobial agents - influence on environmental and reference strains.

    PubMed

    Koziróg, Anna; Brycki, Bogumił

    2015-01-01

    Quaternary ammonium salts (QAS) belong to surfactant commonly used both, in the household and in different branches of industry, primarily in the process of cleaning and disinfection. They have several positive features inter alia effectively limiting the development of microorganisms on many surfaces. In the present work, two compounds were used as biocides: hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) that belongs to the gemini surfactant (GS), and its single analogue - dodecyl(trimethyl)ammonium bromide (DTAB). Two fold dilution method was used to determine the minimum concentration of compounds (MIC) which inhibit the growth of bacteria: Staphylococcus aureus (ATCC 6538 and an environmental strain), Pseudomonas aeruginosa (ATCC 85327 and an environmental strain), and yeast Candida albicans (ATCC 11509 and an environmental strain). The viability of cells in liquid cultures with addition of these substances at ¼ MIC, ½ MIC and MIC concentrations were also determined. The obtained results show that DTAB inhibits the growth of bacteria at the concentration of 0.126-1.010 µM/ml, and gemini surfactant is active at 0.036-0.029 µM/ml. Therefore, GS is active at more than 17-70-fold lower concentrations than its monomeric analogue. Strains isolated from natural environment are less sensitive upon testing biocides than the references strains. Both compounds at the MIC value reduced the number of cells of all strains. The use of too low concentration of biocides can limit the growth of microorganisms, but often only for a short period of time in case of special environmental strains. Later on, they can adapt to adverse environmental conditions and begin to evolve defence mechanisms. PMID:26641636

  4. Effects of spacer chain length of amino acid-based gemini surfactants on wormlike micelle formation.

    PubMed

    Sakai, Kenichi; Nomura, Kazuyuki; Shrestha, Rekha Goswami; Endo, Takeshi; Sakamoto, Kazutami; Sakai, Hideki; Abe, Masahiko

    2014-01-01

    We studied the effects of the spacer chain length of amino acid-based gemini surfactants on the formation of wormlike micelles in aqueous solutions. The surfactants used were synthesized by reacting dodecanoylglutamic acid anhydride with diamine compounds (ethylenediamine, pentanediamine, and octanediamine), and were abbreviated as 12-GsG-12 (s: the spacer chain length of 2, 5, and 8 methylene units). These surfactants yielded viscoelastic wormlike micellar solutions at pH 9 upon mixing with a cationic monomeric surfactant, hexadecyltrimethylammonium bromide (HTAB). We found that the rheological behavior was strongly dependent on the spacer chain length and HTAB concentration. When the shortest spacer chain analogue (12-G2G-12) was used, an increased HTAB concentration resulted in the following structural transformations of the micelles: (i) spherical or rodlike micelles; (ii) anionic wormlike micelles exhibiting a transient network structure; (iii) anionic wormlike micelles with a micellar branching or interconnected structure; and (iv) cationic wormlike micelles. Similarly, when the middle spacer chain analogue (12-G5G-12) was used, a structural transformation from anionic to cationic wormlike micelles occurs; however, molecular aggregates with a lower positive curvature were also formed in this transition region. When the longest spacer analogue (12-G8G-12) was used, the formation of cation-rich molecular aggregates was not observed. These transition behaviors were attributed to the packing geometry of the gemini surfactants with HTAB. Additionally, as the spacer chain length increased, the zero-shear viscosity in the anionic wormlike micellar region decreased, suggesting limited one-dimensional micellar growth of spherical, rodlike, or anionic wormlike micelles.

  5. Expression of aquaporin-3 and -8 mRNAs in the parr and smolt stages of sockeye salmon, Oncorhynchus nerka: effects of cortisol treatment and seawater acclimation.

    PubMed

    Choi, Young Jae; Shin, Hyun Suk; Kim, Na Na; Cho, Sung Hwoan; Yamamoto, Yuzo; Ueda, Hiroshi; Lee, Jehee; Choi, Cheol Young

    2013-06-01

    This study aimed to examine the role of 2 aquaporin (AQP) isoforms (AQP3, and -8) in sockeye salmon (Oncorhynchus nerka) in response to a hyperosmotic challenge from freshwater to seawater (SW) during the parr and smoltification (smolt) stages. AQP3 mRNA was primarily detected in the osmoregulatory organs, such as gills, while AQP8 mRNA was primarily found in the intestine. These results suggested that AQP isoforms play a role in osmoregulation in specific osmoregulatory organs. Similarly, AQP3 mRNA expression in the gills (mean values:1.06 ± 0.05 [parr] and 1.29 ± 0.07 [smolt]) was significantly higher than AQP8 mRNA levels (parr: 0.04 ± 0.003; smolt: 0.14 ± 0.004), and in the intestine, AQP8 mRNA expression (parr: 0.89 ± 0.007; smolt: 1.91 ± 0.03) was significantly higher than AQP3 mRNA levels (parr: 0.24 ± 0.006; smolt: 0.83 ± 0.005); these expression patterns were similar in vivo and in vitro. Additionally, AQP mRNA levels were lower in cortisol treated than in control groups. Therefore, these results suggest that AQPs play important roles in the water absorption mechanisms associated with multiple AQP isoforms, and that cortisol enhances the hypo-osmoregulatory capacity of fish in SW, and also controls the expression of AQPs in a hyperosmotic environment. PMID:23507572

  6. Aqueous Two-Phase System (ATPS) Containing Gemini (12-3-12,2Br-)and SDS 1: Phase Diagram and Properties of ATPS

    SciTech Connect

    Shang, Yazhuo; Liu, Honglai; Hu, Ying; Prausnitz, John M.

    2005-07-21

    Two phases coexist in an aqueous system that contains the two surfactants cationic gemini 12-3-12,2Br- and anionic SDS. An aqueous two-phase system (ATPS) is formed in a narrow region of the ternary phase diagram different from that of traditional aqueous cationic-anionic surfactant systems. In that region, the molar ratio of gemini to SDS varies with the total concentration of surfactants. ATPS not only has higher stability but also has longer phase separation time for the new systems than that of the traditional system. Furthermore, the optical properties of ATPS are different at different total concentrations. All of these experimental observations can be attributed to the unique properties of gemini surfactant and the synergy between the cationic gemini surfactant and the anionic surfactant SDS.

  7. Vadose Zone Remediation Assessment: M-Area Process Sewer Soil Vapor Extraction Units 782-5M, 782-7M, and 782-8M

    SciTech Connect

    Riha, B.D.

    2001-04-20

    This study focuses on the status of the vadose zone remediation along 1600 ft of the process sewer line between the M-Area security fence and the M-Area settling basin. Three soil vapor extraction (SVE) units 782-5M, 782-7M, and 782-8M, connected to 4 vertical wells and 3 horizontal wells have been addressing the vadose zone volatile organic contamination (VOC) since 1995. The specific objectives of this study were to obtain soil gas and sediment samples, evaluate SVE units and vadose zone remediation, and make recommendations to address further remediation needs.

  8. [Results obtained from more intensive antenatal and intranatal attention to gemini pregnancy at gynaecological hospital of Karl-Marx-Stadt region (author's transl)].

    PubMed

    Schmidt, J; Cimutta, B; Müller, K

    1979-01-01

    Studies undertaken into gemini births between 1968 and 1977 have shown that reduction in perinatal mortality has been obtainable from high-intensity programmes of antenatal and intranatal attention to multiparae. Perinatal mortality had accounted for 13.4 per cent, between 1968 and 1974, and dropped to 7.4 per cent, between 1975 and 1977. This achievement is analysed and discussed. More improvement may best be expected from earlier detection of gemini pregnancy and earlier action of intensive care.

  9. Structural studies of the formation of lipoplexes between siRNA and selected bis-imidazolium gemini surfactants.

    PubMed

    Andrzejewska, W; Pietralik, Z; Skupin, M; Kozak, M

    2016-10-01

    Dicationic (gemini) surfactants are agents that can be used for the preparation of stable complexes of nucleic acids, particularly siRNA for therapeutic purposes. In this study, we demonstrated that bis-imidazolium gemini surfactants with variable lengths of dioxyalkyl linker groups (from dioxyethyl to dioxydodecyl) and dodecyl side chains are excellent for the complexation of siRNA. All of these compounds effectively complexed siRNA in a charge ratio range (p/n) of 1.5-10. The low resolution structure of siRNA oligomers was characterised by small angle scattering of synchrotron radiation (SR-SAXS) and ab initio modelling. The structures of the formed complexes were also analysed using SR-SAXS, circular dichroism studies and electrophoretic mobility tests. The most promising agents for complexation with siRNA were the surfactants that contained dioxyethyl and dioxyhexyl spacer groups. PMID:27424091

  10. Processing requirements of secure C3/I and battle management systems - Development of Gemini trusted multiple microcomputer base

    NASA Astrophysics Data System (ADS)

    Tao, T. F.; Schell, R. R.

    The present investigation is concerned with the potential applications of trusted computer system technologies in space. It is suggested that the rapidly expanding roles of new space defense missions will require space-borne command, control, communication, intelligence, and battle management (C2/I-BM) systems. The trusted computer system technology can be extended to develop new computer architectures which are able to support the broader requirements of C3/I-BM processing. The Gemini Trusted Multiple Microcomputer Base product is being developed to meet the demanding requirements and to support simultaneously the multiple capabilities. Attention is given to recent important events of trusted computer system developments, and to the Gemini system architecture.

  11. The Gemini Planet-finding Campaign: The Frequency Of Giant Planets around Debris Disk Stars

    NASA Astrophysics Data System (ADS)

    Wahhaj, Zahed; Liu, Michael C.; Nielsen, Eric L.; Biller, Beth A.; Hayward, Thomas L.; Close, Laird M.; Males, Jared R.; Skemer, Andrew; Ftaclas, Christ; Chun, Mark; Thatte, Niranjan; Tecza, Matthias; Shkolnik, Evgenya L.; Kuchner, Marc; Reid, I. Neill; de Gouveia Dal Pino, Elisabete M.; Alencar, Silvia H. P.; Gregorio-Hetem, Jane; Boss, Alan; Lin, Douglas N. C.; Toomey, Douglas W.

    2013-08-01

    We have completed a high-contrast direct imaging survey for giant planets around 57 debris disk stars as part of the Gemini NICI Planet-Finding Campaign. We achieved median H-band contrasts of 12.4 mag at 0.''5 and 14.1 mag at 1'' separation. Follow-up observations of the 66 candidates with projected separation <500 AU show that all of them are background objects. To establish statistical constraints on the underlying giant planet population based on our imaging data, we have developed a new Bayesian formalism that incorporates (1) non-detections, (2) single-epoch candidates, (3) astrometric and (4) photometric information, and (5) the possibility of multiple planets per star to constrain the planet population. Our formalism allows us to include in our analysis the previously known β Pictoris and the HR 8799 planets. Our results show at 95% confidence that <13% of debris disk stars have a >=5 M Jup planet beyond 80 AU, and <21% of debris disk stars have a >=3 M Jup planet outside of 40 AU, based on hot-start evolutionary models. We model the population of directly imaged planets as d 2 N/dMdavpropm α a β, where m is planet mass and a is orbital semi-major axis (with a maximum value of a max). We find that β < -0.8 and/or α > 1.7. Likewise, we find that β < -0.8 and/or a max < 200 AU. For the case where the planet frequency rises sharply with mass (α > 1.7), this occurs because all the planets detected to date have masses above 5 M Jup, but planets of lower mass could easily have been detected by our search. If we ignore the β Pic and HR 8799 planets (should they belong to a rare and distinct group), we find that <20% of debris disk stars have a >=3 M Jup planet beyond 10 AU, and β < -0.8 and/or α < -1.5. Likewise, β < -0.8 and/or a max < 125 AU. Our Bayesian constraints are not strong enough to reveal any dependence of the planet frequency on stellar host mass. Studies of transition disks have suggested that about 20% of stars are undergoing planet

  12. Enhanced aqueous solubility of polycyclic aromatic hydrocarbons by green diester-linked cationic gemini surfactants and their binary solutions

    NASA Astrophysics Data System (ADS)

    Panda, Manorama; Fatma, Nazish; Kabir-ud-Din

    2016-07-01

    Three homologues of a novel biodegradable diester-linked cationic gemini surfactant series, CmH2m+1 (CH3)2N+(CH2COOCH2)2N+(CH3)2CmH2m+1.2Cl- (m-E2-m; m = 12, 14, 16), were used for investigation of the solubilization of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, anthracene and pyrene in single as well as binary surfactant solutions. Physicochemical parameters of the pure/mixed systems were derived by conductivity and surface tension measurements. Dissolution capacity of the equimolar binary surfactant solutions towards the PAHs was studied from the molar solubilization ratio (MSR), micelle-water partition coefficient (Km) and free energy of solubilization (ΔGs0) of the solubilizates. Influence of hydrophobic chain length of the dimeric surfactants on solubilization was characterized. Aqueous solubility of the PAHs was enhanced linearly with concentration of the surfactant in all the pure and mixed gemini-gemini surfactant systems.

  13. Gemini: a UK twin birth cohort with a focus on early childhood weight trajectories, appetite and the family environment.

    PubMed

    van Jaarsveld, Cornelia H M; Johnson, Laura; Llewellyn, Clare; Wardle, Jane

    2010-02-01

    Gemini is a cohort study of young twins in the United Kingdom designed to assess genetic and environmental influences on early childhood weight trajectories with a focus on infant appetite and the family environment. A total of 2402 families with twins born in England and Wales between March and December 2007 agreed to participate and returned completed baseline questionnaires. The sample includes 1586 same-sex and 816 opposite-sex twins. The study is currently funded for 5 years of follow-up, but is planned to continue into early adolescence and beyond, pending funding. With current funding of the study, families will be followed up when twins are: 8 months old (baseline), and then at 15, 20, 24, 36 and 48 months of age. Gemini is in its early stages, with baseline and first follow-up data collection completed. This is the first twin cohort to focus on childhood weight gain with detailed and repeated measures of children's appetite, food preferences, activity behavior and parental feeding styles, alongside detailed and repeated collection of anthropometrics. This article reviews the rationale for the Gemini study, its representativeness and the main measures.

  14. Physical Characterization of Gemini Surfactant-Based Synthetic Vectors for the Delivery of Linear Covalently Closed (LCC) DNA Ministrings.

    PubMed

    Sum, Chi Hong; Nafissi, Nafiseh; Slavcev, Roderick A; Wettig, Shawn

    2015-01-01

    In combination with novel linear covalently closed (LCC) DNA minivectors, referred to as DNA ministrings, a gemini surfactant-based synthetic vector for gene delivery has been shown to exhibit enhanced delivery and bioavailability while offering a heightened safety profile. Due to topological differences from conventional circular covalently closed (CCC) plasmid DNA vectors, the linear topology of LCC DNA ministrings may present differences with regards to DNA interaction and the physicochemical properties influencing DNA-surfactant interactions in the formulation of lipoplexed particles. In this study, N,N-bis(dimethylhexadecyl)-α,ω-propanediammonium(16-3-16)gemini-based synthetic vectors, incorporating either CCC plasmid or LCC DNA ministrings, were characterized and compared with respect to particle size, zeta potential, DNA encapsulation, DNase sensitivity, and in vitro transgene delivery efficacy. Through comparative analysis, differences between CCC plasmid DNA and LCC DNA ministrings led to variations in the physical properties of the resulting lipoplexes after complexation with 16-3-16 gemini surfactants. Despite the size disparities between the plasmid DNA vectors (CCC) and DNA ministrings (LCC), differences in DNA topology resulted in the generation of lipoplexes of comparable particle sizes. The capacity for ministring (LCC) derived lipoplexes to undergo complete counterion release during lipoplex formation contributed to improved DNA encapsulation, protection from DNase degradation, and in vitro transgene delivery.

  15. Gemini/GMOS Spectroscopy of 26 Strong-lensing-selected Galaxy Cluster Cores

    NASA Astrophysics Data System (ADS)

    Bayliss, Matthew B.; Hennawi, Joseph F.; Gladders, Michael D.; Koester, Benjamin P.; Sharon, Keren; Dahle, Håkon; Oguri, Masamune

    2011-03-01

    We present results from a spectroscopic program targeting 26 strong-lensing cluster cores that were visually identified in the Sloan Digital Sky Survey (SDSS) and the Second Red-Sequence Cluster Survey (RCS-2). The 26 galaxy cluster lenses span a redshift range of 0.2 < z < 0.65, and our spectroscopy reveals 69 unique background sources with redshifts as high as z = 5.200. We also identify redshifts for 262 cluster member galaxies and measure the velocity dispersions and dynamical masses for 18 clusters where we have redshifts for N >= 10 cluster member galaxies. We account for the expected biases in dynamical masses of strong-lensing-selected clusters as predicted by results from numerical simulations and discuss possible sources of bias in our observations. The median dynamical mass of the 18 clusters with N >= 10 spectroscopic cluster members is M Vir = 7.84 × 1014 M sun h -1 0.7, which is somewhat higher than predictions for strong-lensing-selected clusters in simulations. The disagreement is not significant considering the large uncertainty in our dynamical data, systematic uncertainties in the velocity dispersion calibration, and limitations of the theoretical modeling. Nevertheless our study represents an important first step toward characterizing large samples of clusters that are identified in a systematic way as systems exhibiting dramatic strong-lensing features. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: The United States, The United Kingdom, Canada, Chile, Australia, Brazil, and Argentina, with supporting data collected at the Subaru Telescope, operated by the National Astronomical Observatory of Japan; the 2.5 m Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los

  16. SPATIALLY RESOLVED M-BAND EMISSION FROM IO’S LOKI PATERA–FIZEAU IMAGING AT THE 22.8 m LBT

    SciTech Connect

    Conrad, Albert; Veillet, Christian; Kleer, Katherine de; Pater, Imke de; Leisenring, Jarron; Defrère, Denis; Hinz, Philip; Skemer, Andy; Camera, Andrea La; Bertero, Mario; Boccacci, Patrizia; Arcidiacono, Carmelo; Hofmann, Karl-Heinz; Schertl, Dieter; Weigelt, Gerd; Kürster, Martin; Rathbun, Julie; Skrutskie, Michael; Spencer, John; Woodward, Charles E.

    2015-05-15

    The Large Binocular Telescope Interferometer mid-infrared camera, LMIRcam, imaged Io on the night of 2013 December 24 UT and detected strong M-band (4.8 μm) thermal emission arising from Loki Patera. The 22.8 m baseline of the Large Binocular Telescope provides an angular resolution of ∼32 mas (∼100 km at Io) resolving the Loki Patera emission into two distinct maxima originating from different regions within Loki’s horseshoe lava lake. This observation is consistent with the presence of a high-temperature source observed in previous studies combined with an independent peak arising from cooling crust from recent resurfacing. The deconvolved images also reveal 15 other emission sites on the visible hemisphere of Io including two previously unidentified hot spots.

  17. Cu NQR Study of Impurity-doped YBa_2(Cu_1-xM_x)_4O8 (M=Ni, Zn)

    NASA Astrophysics Data System (ADS)

    Itoh, Yutaka; Machi, Takato; Watanabe, Nobuaki; Koshizuka, Naoki

    2001-03-01

    We report Cu NQR measurements of ^63Cu(2) nuclear spin-lattice relaxation curves for the impurity-doped powdered YBa_2(Cu_1-xM_x)_4O8 (M=Ni, x=0 ~0.042 M=Zn, x=0 ~0.022) from 4.2 K to 300 K. We estimated the host and the impurity-induced Cu nuclear spin-lattice relaxation times from the nonexponential recovery curves. Near the superconductor-to-semiconductor transition at the critical impurity concentration, we observed that the wipeout effect works at low temperature and that the pseudo spin-gap behavior of the host Cu nuclear spin-lattice relaxation rate (1/T_1T)_HOST is suppressed. We associate these results with the localization effect in conduction. This work was supported by New Energy and Industrial Technology Development Organization (NEDO) as Collaborative Research and Development of Fundamental Technologies for Superconductivity Applications.

  18. Monitoring non-periodic comet C/2011 L4 PANSTARRS using Joan Oró 0.8 m robotic telescope at OAdM

    NASA Astrophysics Data System (ADS)

    Trigo-Rodríguez, J. M.; Rodríguez, D.; Lacruz, J.; Sánchez, A.

    2013-09-01

    Comet C/2011 L4 PANSTARRS was discovered in June 2011 by R. Wainscoat and D. Tholen using the Pan-STARRS telescope located near the summit of Haleakala, on the island of Maui in Hawaii (USA) [1]. Once its orbit was computed it was noticed its non-periodic nature and the favorable geometry during its approach to perihelion in March 2013. It first became visible to the naked eye from the Southern hemisphere, and later on it started to be seen during mid-March from the Northern one. Due to the limited observational period in right conditions we introduce here some observations obtained taken from robotic 0.8 m Telescope Joan Oró (JO) from the Observatori Astronòmic del Montsec (OAdM: www.oadm.cat) and other Spanish observatories.

  19. RECOVERY OF THE CANDIDATE PROTOPLANET HD 100546 b WITH GEMINI/NICI AND DETECTION OF ADDITIONAL (PLANET-INDUCED?) DISK STRUCTURE AT SMALL SEPARATIONS

    SciTech Connect

    Currie, Thayne; Kudo, Tomoyuki; Muto, Takayuki; Honda, Mitsuhiko; Brandt, Timothy D.; Grady, Carol; Fukagawa, Misato; Burrows, Adam; Janson, Markus; Kuzuhara, Masayuki; McElwain, Michael W.; Follette, Katherine; Hashimoto, Jun; Henning, Thomas; Kandori, Ryo; Kusakabe, Nobuhiko; Morino, Jun-ichi; Nishikawa, Jun; Kwon, Jungmi; Mede, Kyle; and others

    2014-12-01

    We report the first independent, second epoch (re-)detection of a directly imaged protoplanet candidate. Using L' high-contrast imaging of HD 100546 taken with the Near-Infrared Coronagraph and Imager on Gemini South, we recover ''HD 100546 b'' with a position and brightness consistent with the original Very Large Telescope/NAos-COnica detection from Quanz et al., although data obtained after 2013 will be required to decisively demonstrate common proper motion. HD 100546 b may be spatially resolved, up to ≈12-13 AU in diameter, and is embedded in a finger of thermal IR-bright, polarized emission extending inward to at least 0.''3. Standard hot-start models imply a mass of ≈15 M{sub J} . However, if HD 100546 b is newly formed or made visible by a circumplanetary disk, both of which are plausible, its mass is significantly lower (e.g., 1-7 M{sub J} ). Additionally, we discover a thermal IR-bright disk feature, possibly a spiral density wave, at roughly the same angular separation as HD 100546 b but 90° away. Our interpretation of this feature as a spiral arm is not decisive, but modeling analyses using spiral density wave theory implies a wave launching point exterior to ≈0.''45 embedded within the visible disk structure: plausibly evidence for a second, hitherto unseen, wide-separation planet. With one confirmed protoplanet candidate and evidence for one to two others, HD 100546 is an important evolutionary precursor to intermediate-mass stars with multiple super-Jovian planets at moderate/wide separations like HR 8799.

  20. Recovery of the Candidate Protoplanet HD 100546 b with Gemini/NICI and Detection of Additional (Planet-induced?) Disk Structure at Small Separations

    NASA Astrophysics Data System (ADS)

    Currie, Thayne; Muto, Takayuki; Kudo, Tomoyuki; Honda, Mitsuhiko; Brandt, Timothy D.; Grady, Carol; Fukagawa, Misato; Burrows, Adam; Janson, Markus; Kuzuhara, Masayuki; McElwain, Michael W.; Follette, Katherine; Hashimoto, Jun; Henning, Thomas; Kandori, Ryo; Kusakabe, Nobuhiko; Kwon, Jungmi; Mede, Kyle; Morino, Jun-ichi; Nishikawa, Jun; Pyo, Tae-Soo; Serabyn, Gene; Suenaga, Takuya; Takahashi, Yasuhiro; Wisniewski, John; Tamura, Motohide

    2014-12-01

    We report the first independent, second epoch (re-)detection of a directly imaged protoplanet candidate. Using L' high-contrast imaging of HD 100546 taken with the Near-Infrared Coronagraph and Imager on Gemini South, we recover "HD 100546 b" with a position and brightness consistent with the original Very Large Telescope/NAos-COnica detection from Quanz et al., although data obtained after 2013 will be required to decisively demonstrate common proper motion. HD 100546 b may be spatially resolved, up to ≈12-13 AU in diameter, and is embedded in a finger of thermal IR-bright, polarized emission extending inward to at least 0.''3. Standard hot-start models imply a mass of ≈15 MJ . However, if HD 100546 b is newly formed or made visible by a circumplanetary disk, both of which are plausible, its mass is significantly lower (e.g., 1-7 MJ ). Additionally, we discover a thermal IR-bright disk feature, possibly a spiral density wave, at roughly the same angular separation as HD 100546 b but 90° away. Our interpretation of this feature as a spiral arm is not decisive, but modeling analyses using spiral density wave theory implies a wave launching point exterior to ≈0.''45 embedded within the visible disk structure: plausibly evidence for a second, hitherto unseen, wide-separation planet. With one confirmed protoplanet candidate and evidence for one to two others, HD 100546 is an important evolutionary precursor to intermediate-mass stars with multiple super-Jovian planets at moderate/wide separations like HR 8799.

  1. Hydrophilic interaction liquid chromatography-tandem mass spectrometry quantitative method for the cellular analysis of varying structures of gemini surfactants designed as nanomaterial drug carriers.

    PubMed

    Donkuru, McDonald; Michel, Deborah; Awad, Hanan; Katselis, George; El-Aneed, Anas

    2016-05-13

    Diquaternary gemini surfactants have successfully been used to form lipid-based nanoparticles that are able to compact, protect, and deliver genetic materials into cells. However, what happens to the gemini surfactants after they have released their therapeutic cargo is unknown. Such knowledge is critical to assess the quality, safety, and efficacy of gemini surfactant nanoparticles. We have developed a simple and rapid liquid chromatography electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the quantitative determination of various structures of gemini surfactants in cells. Hydrophilic interaction liquid chromatography (HILIC) was employed allowing for a short simple isocratic run of only 4min. The lower limit of detection (LLOD) was 3ng/mL. The method was valid to 18 structures of gemini surfactants belonging to two different structural families. A full method validation was performed for two lead compounds according to USFDA guidelines. The HILIC-MS/MS method was compatible with the physicochemical properties of gemini surfactants that bear a permanent positive charge with both hydrophilic and hydrophobic elements within their molecular structure. In addition, an effective liquid-liquid extraction method (98% recovery) was employed surpassing previously used extraction methods. The analysis of nanoparticle-treated cells showed an initial rise in the analyte intracellular concentration followed by a maximum and a somewhat more gradual decrease of the intracellular concentration. The observed intracellular depletion of the gemini surfactants may be attributable to their bio-transformation into metabolites and exocytosis from the host cells. Obtained cellular data showed a pattern that grants additional investigations, evaluating metabolite formation and assessing the subcellular distribution of tested compounds.

  2. Energy and nutrient intakes of young children in the UK: findings from the Gemini twin cohort.

    PubMed

    Syrad, H; Llewellyn, C H; van Jaarsveld, C H M; Johnson, L; Jebb, S A; Wardle, J

    2016-05-28

    Data on the diets of young children in the UK are limited, despite growing evidence of the importance of early diet for long-term health. We used the largest contemporary dietary data set to describe the intake of 21-month-old children in the UK. Parents of 2336 children aged 21 months from the UK Gemini twin cohort completed 3-d diet diaries in 2008/2009. Family background information was obtained from questionnaires completed 8 months after birth. Mean total daily intakes of energy, macronutrients (g and %E) and micronutrients from food and beverages, including and excluding supplements, were derived. Comparisons with UK dietary reference values (DRV) were made using t tests and general linear regression models, respectively. Daily energy intake (kJ), protein (g) and most micronutrients exceeded DRV, except for vitamin D and Fe, where 96 or 84 % and 70 or 6 % of children did not achieve the reference nutrient intake or lower reference nutrient intake (LRNI), respectively, even with supplementation. These findings reflect similar observations in the smaller sample of children aged 18-36 months in the National Diet and Nutrition Survey. At a population level, young children in the UK are exceeding recommended daily intakes of energy and protein, potentially increasing their risk of obesity. The majority of children are not meeting the LRNI for vitamin D, largely reflecting inadequate use of the supplements recommended at this age. Parents may need more guidance on how to achieve healthy energy and nutrient intakes for young children.

  3. GEMINI: Initial behavioral results after full severance of the cervical spinal cord in mice

    PubMed Central

    Kim, C-Yoon; Oh, Hanseul; Hwang, In-Kyu; Hong, Ki-Sung

    2016-01-01

    Background: The GEMINI spinal cord fusion protocol has been developed to achieve a successful cephalosomatic anastomosis. Here, we report the preliminary data on the use of a fusogen [polyethylene glycol (PEG)] after full cervical cord transection in mice to facilitate the fusion of both ends of a sharply transected spinal cord. Methods: Cervical laminectomy and a complete, visually confirmed cervical cord (C 5) transection was performed on female albino mice (n = 16). In Group 1 (n = 8), a fusogen, (PEG) was used to bridge the gap between the cut ends of the spinal cord. Group 2 received the same spinal cord transection but was treated with saline. Outcome was assessed daily using a standard scale (modified 22-point Basso-Beattie-Bresnahan scale) and filmed on camera. Results: The PEG group (group 1) showed partial restoration of motor function after 4 weeks of observation; group 2 (placebo) did not recover any useful motor activity. Conclusion: In this preliminary experiment, PEG, but not saline, promoted partial motor recovery in mice submitted to full cervical transection. PMID:27656325

  4. GEMINI: Initial behavioral results after full severance of the cervical spinal cord in mice

    PubMed Central

    Kim, C-Yoon; Oh, Hanseul; Hwang, In-Kyu; Hong, Ki-Sung

    2016-01-01

    Background: The GEMINI spinal cord fusion protocol has been developed to achieve a successful cephalosomatic anastomosis. Here, we report the preliminary data on the use of a fusogen [polyethylene glycol (PEG)] after full cervical cord transection in mice to facilitate the fusion of both ends of a sharply transected spinal cord. Methods: Cervical laminectomy and a complete, visually confirmed cervical cord (C 5) transection was performed on female albino mice (n = 16). In Group 1 (n = 8), a fusogen, (PEG) was used to bridge the gap between the cut ends of the spinal cord. Group 2 received the same spinal cord transection but was treated with saline. Outcome was assessed daily using a standard scale (modified 22-point Basso-Beattie-Bresnahan scale) and filmed on camera. Results: The PEG group (group 1) showed partial restoration of motor function after 4 weeks of observation; group 2 (placebo) did not recover any useful motor activity. Conclusion: In this preliminary experiment, PEG, but not saline, promoted partial motor recovery in mice submitted to full cervical transection.

  5. Adaptive Optics for Direct Detection of Extrasolar Planets: The Gemini Planet Imager

    SciTech Connect

    Macintosh, B; Graham, J; Palmer, D; Doyon, R; Gavel, D; Larkin, J; Oppenheimer, B; Saddlemyer, L; Wallace, J K; Bauman, B; Erikson, D; Poyneer, L; Sivaramakrishnan, A; Soummer, R; Veran, J

    2007-04-24

    The direct detection of photons emitted or reflected by extrasolar planets, spatially resolved from their parent star, is a major frontier in the study of other solar systems. Direct detection will provide statistical information on planets in 5-50 AU orbits, inaccessible to current Doppler searches, and allow spectral characterization of radius, temperature, surface gravity, and perhaps composition. Achieving this will require new dedicated high-contrast instruments. One such system under construction is the Gemini Planet Imager (GPI.) This combines a high-order/high-speed adaptive optics system to control wavefront errors from the Earth's atmosphere, an advanced coronagraph to block diffraction, ultrasmooth optics, a precision infrared interferometer to measure and correct systematic errors, and a integral field spectrograph/polarimeter to image and characterize target planetary systems. We predict that GPI will be able to detect planets with brightness less than 10{sup -7} of their parent star, sufficient to observe warm self-luminous planets around a large population of targets.

  6. The Peculiar Debris Disk of HD 111520 as Resolved by the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Draper, Zachary H.; Duchêne, Gaspard; Millar-Blanchaer, Maxwell A.; Matthews, Brenda C.; Wang, Jason J.; Kalas, Paul; Graham, James R.; Padgett, Deborah; Ammons, S. Mark; Bulger, Joanna; Chen, Christine; Chilcote, Jeffrey K.; Doyon, René; Fitzgerald, Michael P.; Follette, Kate B.; Gerard, Benjamin; Greenbaum, Alexandra Z.; Hibon, Pascale; Hinkley, Sasha; Macintosh, Bruce; Ingraham, Patrick; Lafrenière, David; Marchis, Franck; Marois, Christian; Nielsen, Eric L.; Oppenheimer, Rebecca; Patel, Rahul; Patience, Jenny; Perrin, Marshall; Pueyo, Laurent; Rajan, Abhijith; Rameau, Julien; Sivaramakrishnan, Anand; Vega, David; Ward-Duong, Kimberly; Wolff, Schuyler G.

    2016-08-01

    Using the Gemini Planet Imager, we have resolved the circumstellar debris disk around HD 111520 at a projected range of ˜30–100 AU in both total and polarized H-band intensity. The disk is seen edge-on at a position angle of 165° along the spine of emission. A slight inclination and asymmetric warp are covariant and alter the interpretation of the observed disk emission. We employ three point-spread function subtraction methods to reduce the stellar glare and instrumental artifacts to confirm that there is a roughly 2:1 brightness asymmetry between the NW and SE extension. This specific feature makes HD 111520 the most extreme example of asymmetric debris disks observed in scattered light among similar highly inclined systems, such as HD 15115 and HD 106906. We further identify a tentative localized brightness enhancement and scale height enhancement associated with the disk at ˜40 AU away from the star on the SE extension. We also find that the fractional polarization rises from 10% to 40% from 0.″5 to 0.″8 from the star. The combination of large brightness asymmetry and symmetric polarization fraction leads us to believe that an azimuthal dust density variation is causing the observed asymmetry.

  7. Thermo-responsive properties driven by hydrogen bonding in aqueous cationic gemini surfactant systems.

    PubMed

    Wei, Xi-Lian; Han, Chuan-Hong; Geng, Pei-Pei; Chen, Xiao-Xiao; Guo, Yan; Liu, Jie; Sun, De-Zhi; Zhang, Jun-Hong; Yu, Meng-Jiao

    2016-02-01

    A series of unexpected thermo-responsive phenomena were discovered in an aqueous solution of the cationic gemini surfactant, 2-hydroxypropyl-1,3-bis(alkyldimethylammonium chloride) (n-3(OH)-n(2Cl), n = 14, 16), in the presence of an inorganic salt. The viscosity change trend for the 14-3(OH)-14(2Cl) system was investigated in the 20-40 °C temperature range. As the temperature increased, the viscosity of the solution first decreased to a minimum point corresponding to 27 °C, and then increased until a maximum was reached, after which the viscosity decreased again. In the 16-3(OH)-16(2Cl) system, the gelling temperature (T(gel)) and viscosity changes upon heating were similar to those in the 14-3(OH)-14(2Cl) system above 27 °C. The reversible conversion of elastic hydrogel to wormlike micelles in the aqueous solution of the 16-3(OH)-16(2Cl) system in the presence of an inorganic salt was observed at relatively low temperatures. Various techniques were used to study and verify the phase-transition processes in these systems, including rheological measurements, cryogenic transmission electron microscopy (cryo-TEM), electric conductivity, and differential scanning calorimetry. The abovementioned phenomena were explained by the formation and destruction of intermolecular hydrogen bonds, and the transition mechanisms of the aggregates were analyzed accordingly.

  8. A Gemini Planet Imager investigation of the atmosphere of the HD 95086b planet

    NASA Astrophysics Data System (ADS)

    De Rosa, Robert J.; Pueyo, Laurent; Patience, Jenny; Graham, James R.; Gemini Planet Imager Team

    2015-01-01

    We present Gemini Planet Imager (GPI) near-infrared observations of the ~5 Mjup companion to the young, dusty A-type star HD 95086, observed during the course of the verification and commissioning of the instrument. By combining binned low-resolution H and K-band IFS spectra from GPI, with literature near and mid-IR photometry, we have undertaken the most comprehensive analysis of the spectral energy distribution of HD 95086 b to-date. Comparing these observational results with atmospheric models, we constrain key parameters such as the effective temperature and surface gravity, and place the results in the context of analyses of other directly imaged planetary-mass companions (e.g. HR 8799 bcde, β Pic b), and other substellar companions at a similar age (e.g. HD 106906 b, GQ Lup b). We also comment on the sensitivity of companions interior and exterior to HD 95086 b. Lastly, we present the color-corrections derived during the course of this study that are required to transform photometry obtained with GPI in the K1 and K2 filters into both the MKO and 2MASS photometric systems, essential for the propoer interpretation of K-band photometry measurements obtained with GPI.

  9. NEAR-INFRARED OBSERVATIONS OF GQ LUP b USING THE GEMINI INTEGRAL FIELD SPECTROGRAPH NIFS

    SciTech Connect

    Lavigne, Jean-Francois; Doyon, Rene; Lafreniere, David; Marois, Christian; Barman, Travis

    2009-10-20

    We present new JHK spectroscopy (R approx 5000) of GQ Lup b, acquired with the Near-Infrared Integral Field Spectrograph and the adaptive optics system ALTAIR at the Gemini North telescope. Angular differential imaging was used in the J and H bands to suppress the speckle noise from GQ Lup A; we show that this approach can provide improvements in signal-to-noise ratio (S/N) by a factor of 2-6 for companions located at subarcsecond separations. Based on high-quality observations and Global Astrometric lnterferometer for Astrophysics synthetic spectra, we estimate the companion effective temperature to T {sub eff} = 2400 +- 100 K, its gravity to log g = 4.0 +- 0.5, and its luminosity to log(L/L {sub sun}) = -2.47 +- 0.28. Comparisons with the predictions of the DUSTY evolutionary tracks allow us to constrain the mass of GQ Lup b to 8-60 M {sub Jup}, most likely in the brown dwarf regime. Compared with the spectra published by Seifahrt and collaborators, our spectra of GQ Lup b are significantly redder (by 15%-50%) and do not show important Pabeta emission. Our spectra are in excellent agreement with the lower S/N spectra previously published by McElwain and collaborators.

  10. Constraints on the Architecture of the HD 95086 Planetary System with the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Rameau, Julien; Nielsen, Eric L.; De Rosa, Robert J.; Blunt, Sarah C.; Patience, Jenny; Doyon, René; Graham, James R.; Lafrenière, David; Macintosh, Bruce; Marchis, Franck; Bailey, Vanessa; Chilcote, Jeffrey K.; Duchene, Gaspard; Esposito, Thomas M.; Hung, Li-Wei; Konopacky, Quinn M.; Maire, Jérôme; Marois, Christian; Metchev, Stanimir; Perrin, Marshall D.; Pueyo, Laurent; Rajan, Abhijith; Savransky, Dmitry; Wang, Jason J.; Ward-Duong, Kimberly; Wolff, Schuyler G.; Ammons, S. Mark; Hibon, Pascale; Ingraham, Patrick; Kalas, Paul; Morzinski, Katie M.; Oppenheimer, Rebecca; Rantakyearö, Fredrik T.; Thomas, Sandrine

    2016-05-01

    We present astrometric monitoring of the young exoplanet HD 95086 b obtained with the Gemini Planet Imager between 2013 and 2016. A small but significant position angle change is detected at constant separation; the orbital motion is confirmed with literature measurements. Efficient Monte Carlo techniques place preliminary constraints on the orbital parameters of HD 95086 b. With 68% confidence, a semimajor axis of {61.7}-8.4+20.7 au and an inclination of 153\\fdg {0}-13.5+9.7 are favored, with eccentricity less than 0.21. Under the assumption of a coplanar planet-disk system, the periastron of HD 95086 b is beyond 51 au with 68% confidence. Therefore, HD 95086 b cannot carve the entire gap inferred from the measured infrared excess in the SED of HD 95086. We use our sensitivity to additional planets to discuss specific scenarios presented in the literature to explain the geometry of the debris belts. We suggest that either two planets on moderately eccentric orbits or three to four planets with inhomogeneous masses and orbital properties are possible. The sensitivity to additional planetary companions within the observations presented in this study can be used to help further constrain future dynamical simulations of the planet-disk system.

  11. Fabrication of narrow-slit masks for the Gemini Multiobject Spectrograph

    NASA Astrophysics Data System (ADS)

    Szeto, Kei; Stilburn, James R.; Bond, Tim; Roberts, Scott; Sebesta, Jerry; Saddlemyer, Leslie K.

    1997-03-01

    The fabrication requirements of the Gemini multi-object spectrograph (GMOS) slit mask is discussed particularly in terms of the slit-to-slit position, slit geometry and the telescope operation. The demand for precision slit masks with high quality slits of width of less than quarter arcsecond and an allowable fabrication time of two hours required examination of innovative fabrication processes and mask materials. Different fabrication processes including high precision cutting processes, water-jet and laser machining systems are evaluated according to cost, speed and efficiency, and the findings are documented. Different candidate mask materials including low thermal expansion metals and novel materials such as graphite paper and carbon-fiber composite sheet, are evaluated according to their relevant mechanical and physical properties, and the findings are also documented. In addition to identifying that the most suitable mask material is unidirectional carbon fiber sheet and the corresponding fabrication process is a Nd:YAG laser machining system, the mask handling system for GMOS is described and methodology to minimize systematic fabrication errors is also proposed.

  12. The Peculiar Debris Disk of HD 111520 as Resolved by the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Draper, Zachary H.; Duchêne, Gaspard; Millar-Blanchaer, Maxwell A.; Matthews, Brenda C.; Wang, Jason J.; Kalas, Paul; Graham, James R.; Padgett, Deborah; Ammons, S. Mark; Bulger, Joanna; Chen, Christine; Chilcote, Jeffrey K.; Doyon, René; Fitzgerald, Michael P.; Follette, Kate B.; Gerard, Benjamin; Greenbaum, Alexandra Z.; Hibon, Pascale; Hinkley, Sasha; Macintosh, Bruce; Ingraham, Patrick; Lafrenière, David; Marchis, Franck; Marois, Christian; Nielsen, Eric L.; Oppenheimer, Rebecca; Patel, Rahul; Patience, Jenny; Perrin, Marshall; Pueyo, Laurent; Rajan, Abhijith; Rameau, Julien; Sivaramakrishnan, Anand; Vega, David; Ward-Duong, Kimberly; Wolff, Schuyler G.

    2016-08-01

    Using the Gemini Planet Imager, we have resolved the circumstellar debris disk around HD 111520 at a projected range of ˜30-100 AU in both total and polarized H-band intensity. The disk is seen edge-on at a position angle of 165° along the spine of emission. A slight inclination and asymmetric warp are covariant and alter the interpretation of the observed disk emission. We employ three point-spread function subtraction methods to reduce the stellar glare and instrumental artifacts to confirm that there is a roughly 2:1 brightness asymmetry between the NW and SE extension. This specific feature makes HD 111520 the most extreme example of asymmetric debris disks observed in scattered light among similar highly inclined systems, such as HD 15115 and HD 106906. We further identify a tentative localized brightness enhancement and scale height enhancement associated with the disk at ˜40 AU away from the star on the SE extension. We also find that the fractional polarization rises from 10% to 40% from 0.″5 to 0.″8 from the star. The combination of large brightness asymmetry and symmetric polarization fraction leads us to believe that an azimuthal dust density variation is causing the observed asymmetry.

  13. Aggregation behaviors of gelatin with cationic gemini surfactant at air/water interface.

    PubMed

    Wu, Dan; Xu, Guiying; Feng, Yujun; Li, Yiming

    2007-03-10

    The dilational rheological properties of gelatin with cationic gemini surfactant 1,2-ethane bis(dimethyl dodecyl ammonium bromide) (C(12)C(2)C(12)) at air/water interface were investigated using oscillating barriers method at low frequency (0.005-0.1 Hz), which was compared with single-chain surfactant dodecyltrimethyl ammonium bromide (DTAB). The results indicate that the maximum dilational modulus and the film stability of gelatin-C(12)C(2)C(12) are higher than those of gelatin-DTAB. At high concentration of C(12)C(2)C(12) or DTAB, the dilational modulus of gelatin-surfactant system becomes close to that corresponding to pure surfactant, suggesting gelatin at interface is replaced by surfactant. This replacement is also observed by surface tension measurement. However, it is found that gelatin-C(12)C(2)C(12) system has two obvious breaks but gelatin-DTAB has not in surface tension isotherms. These phenomena are ascribed to the double charges and strong hydrophobicity of C(12)C(2)C(12). Based on these experimental results, a mechanism of gelatin-surfactant interaction at air/water interface is proposed.

  14. Energy and nutrient intakes of young children in the UK: findings from the Gemini twin cohort.

    PubMed

    Syrad, H; Llewellyn, C H; van Jaarsveld, C H M; Johnson, L; Jebb, S A; Wardle, J

    2016-05-28

    Data on the diets of young children in the UK are limited, despite growing evidence of the importance of early diet for long-term health. We used the largest contemporary dietary data set to describe the intake of 21-month-old children in the UK. Parents of 2336 children aged 21 months from the UK Gemini twin cohort completed 3-d diet diaries in 2008/2009. Family background information was obtained from questionnaires completed 8 months after birth. Mean total daily intakes of energy, macronutrients (g and %E) and micronutrients from food and beverages, including and excluding supplements, were derived. Comparisons with UK dietary reference values (DRV) were made using t tests and general linear regression models, respectively. Daily energy intake (kJ), protein (g) and most micronutrients exceeded DRV, except for vitamin D and Fe, where 96 or 84 % and 70 or 6 % of children did not achieve the reference nutrient intake or lower reference nutrient intake (LRNI), respectively, even with supplementation. These findings reflect similar observations in the smaller sample of children aged 18-36 months in the National Diet and Nutrition Survey. At a population level, young children in the UK are exceeding recommended daily intakes of energy and protein, potentially increasing their risk of obesity. The majority of children are not meeting the LRNI for vitamin D, largely reflecting inadequate use of the supplements recommended at this age. Parents may need more guidance on how to achieve healthy energy and nutrient intakes for young children. PMID:27093345

  15. OCTOCAM: a fast multi-channel imager and spectrograph for the Gemini telescopes

    NASA Astrophysics Data System (ADS)

    de Ugarte Postigo, Antonio

    2015-08-01

    OCTOCAM has been proposed as a future instrument for Gemini and is currently going through a feasibility study phase. Its a multi-channel instrument based on the use of high-efficiency dichroics to divide the light into eight optical and near-infrared arms. In its imaging mode it has a field of view of 3’x3’ that is simultaneously observed in eight bands. It is also designed to obtain spectroscopy from 370 to 2,400 nm in a single shot, with a spectral resolution of ~3,000. OCTOCAM will be capable of obtaining full-Stokes spectropolarimetry to study geometry and magnetic fields of astrophysical phenomena. It will be equipped with a mini-IFU (Integral Field Unit) to perform resolved spectroscopic studies in an area of a few arcseconds. Furthermore, thanks to the use of state of the art detectors, it will be able to reach high readout speeds, allowing science cases aimed at high time-resolution. We expect full frame rate reaching speeds of tens of Hertz, which will be even higher for windowed modes. This will also mean that OCTOCAM will virtually eliminate dead times in most observing modes, allowing duty cycles of roughly 100%. In this way, OCTOCAM will cover a region of the (spectral-resolution)-(spectral-coverage)-(temporal-resolution) diagram that is not occupied by any other single instrument in the world.

  16. A Systematic Deuteration Survey in the Gemini OB1 Molecular Cloud

    NASA Astrophysics Data System (ADS)

    Shirley, Yancy L.

    2014-01-01

    Recent maps of dust continuum emission from molecular clouds at submillimeter wavelengths have made it possible to survey and to study the chemistry of entire core and clump populations within a single cloud. One very strong chemical process in star-forming regions is the fractionation of deuterium in molecules which results in an increase in the deuterium ratio many orders of magnitude over the ISM [D]/[H] ratio and provides a chemical probe of cold, dense regions. We present a survey of DCO+ 3-2 emission toward the clump population in the high-mass, star-forming Gemini OB1 molecular cloud complex identified from 1.1 mm continuum imaging by the Bolocam Galactic Plane Survey (BGPS). The peak 1.1 mm continuum positions of 52 clumps were observed with the 10m Heinrich Hertz Submillimeter Telescope operated by the Arizona Radio Observatory. We compare to observations of HCO+ and H13CO+ from the BGPS spectroscopic survey of Shirley et al. to determine the deuterium ratio. We find that DCO+ emission is detected toward 90% of the clumps with a median deuterium ratio of a few percent. DCO+ fractionation anti-correlates with gas kinetic temperature and linewidth, a measure of the amount of turbulence within the clumps.

  17. South Africa

    Atmospheric Science Data Center

    2013-04-16

    article title:  Red Tide Strands South African Rock Lobsters     ... and on atmospheric and oceanic conditions. At Elands Bay in South Africa's Western Cape province, about 1000 tons of rock lobsters beached ...

  18. Supersonic Testing of 0.8 m Disk Gap Band Parachutes in the Wake of a 70 Deg Sphere Cone Entry Vehicle

    NASA Technical Reports Server (NTRS)

    Sengupta, Anita; Wernet, Mark; Roeder, James; Kelsch, Richard; Witkowski, Al; Jones, Thomas

    2009-01-01

    Supersonic wind tunnel testing of Viking-type 0.8 m Disk-Gap-Band (DGB) parachutes was conducted in the NASA Glenn Research Center 10'x10' wind-tunnel. The tests were conducted in support of the Mars Science Laboratory Parachute Decelerator System development and qualification program. The aerodynamic coupling of the entry-vehicle wake to parachute flow-field is under investigation to determine the cause and functional dependence of a supersonic canopy breathing phenomenon referred to as area oscillations, characteristic of DGB's above Mach 1.5 operation. Four percent of full-scale parachutes (0.8 m) were constructed similar to the flight-article in material and construction techniques. The parachutes were attached to a 70-deg sphere-cone entry-vehicle to simulate the Mars flight configuration. The parachutes were tested in the wind-tunnel from Mach 2 to 2.5 in a Reynolds number range of 2x105 to 1x106, representative of a Mars deployment. Three different test configurations were investigated. In the first two configurations, the parachutes were constrained horizontally through the vent region to measure canopy breathing and wake interaction for fixed trim angles of 0 and 10 degrees from the free-stream. In the third configuration the parachute was unconstrained, permitted to trim and cone, similar to free-flight (but capsule motion is constrained), varying its alignment relative to the entry-vehicle wake. Non-intrusive test diagnostics were chosen to quantify parachute performance and provide insight into the flow field structure. An in-line loadcell provided measurement of unsteady and mean drag. Shadowgraph of the upstream parachute flow field was used to capture bow-shock motion and wake coupling. Particle image velocimetry provided first and second order flow field statistics over a planar region of the flow field, just upstream of the parachute. A photogrammetric technique was used to quantify fabric motion using multiple high speed video cameras to record

  19. Cyanide-bridged [Fe8M6] clusters displaying single-molecule magnetism (M=Ni) and electron-transfer-coupled spin transitions (M=Co).

    PubMed

    Mitsumoto, Kiyotaka; Oshiro, Emiko; Nishikawa, Hiroyuki; Shiga, Takuya; Yamamura, Yasuhisa; Saito, Kazuya; Oshio, Hiroki

    2011-08-22

    Cyanide-bridged metal complexes of [Fe(8)M(6)(μ-CN)(14)(CN)(10)(tp)(8)(HL)(10)(CH(3)CN)(2)][PF(6)](4)⋅n CH(3)CN⋅m H(2)O (HL=3-(2-pyridyl)-5-[4-(diphenylamino)phenyl]-1H-pyrazole), tp(-) =hydrotris(pyrazolylborate), 1: M=Ni with n=11 and m=7, and 2: M=Co with n=14 and m=5) were prepared. Complexes 1 and 2 are isomorphous, and crystallized in the monoclinic space group P2(1)/n. They have tetradecanuclear cores composed of eight low-spin (LS) Fe(III) and six high-spin (HS) M(II) ions (M=Ni and Co), all of which are bridged by cyanide ions, to form a crown-like core structure. Magnetic susceptibility measurements revealed that intramolecular ferro- and antiferromagnetic interactions are operative in 1 and in a fresh sample of 2, respectively. Ac magnetic susceptibility measurements of 1 showed frequency-dependent in- and out-of-phase signals, characteristic of single-molecule magnetism (SMM), while desolvated samples of 2 showed thermal- and photoinduced intramolecular electron-transfer-coupled spin transition (ETCST) between the [(LS-Fe(II))(3) (LS-Fe(III))(5)(HS-Co(II))(3)(LS-Co(III))(3)] and the [(LS-Fe(III))(8)(HS-Co(II))(6)] states. PMID:21830241

  20. Structural and electronic properties of graphite and graphite intercalation compounds MC[sub 8] (M = K, Rb, Cs) governing their scanning tunneling microscopy images

    SciTech Connect

    Whangbo, M.H.; Liang, W.; Ren, J. ); Magonov, S.N.; Wawkuschewski, A. )

    1994-08-04

    Several puzzling observations in the scanning tunneling microscopy (STM) and atomic force microscopy (AFM) studies of highly oriented pyrolytic graphite (HOPG) and its intercalation compounds MC[sub 8] (M = K, Rb, Cs) were investigated on the basis of atom-atom potential and Coulombic interaction energy calculations. The charge or spin density wave state of a graphite monolayer is found inconsistent with an identical peak registry of the HOPG STM images obtained at plus and minus bias voltages. Simultaneous STM/AFM measurements of HOPG show the STM and AFM images to have an identical peak registry, which implies that the local hardness of the surface monolayer is larger at the B-site than at the A-site. We confirm this implication by estimating the local hardness in the surface monolayer of a graphite bilayer in terms of atom-atom potential calculations. The essential characteristics of the Moire STM images of HOPG are correctly predicted by the local hardness map obtained for the surface monolayer of a graphite bilayer in terms of atom-atom potential calculations. This supports the notion that the tip-force-induced topography change in the surface monolayer is generally responsible for Moire STM patterns in layered materials. 29 refs., 5 figs., 2 tabs.

  1. Three-Dimensional Assignment of the Structures of Atomic Clusters: an Example of Au8M (M=Si, Ge, Sn) Anion Clusters.

    PubMed

    Liu, Yi-Rong; Huang, Teng; Gai, Yan-Bo; Zhang, Yang; Feng, Ya-Juan; Huang, Wei

    2015-12-03

    Identification of different isomer structures of atomic and molecular clusters has long been a challenging task in the field of cluster science. Here we present a three-dimensional (3D) assignment method, combining the energy (1D) and simulated (2D) spectra to assure the assignment of the global minimum structure. This method is more accurate and convenient than traditional methods, which only consider the total energy and first vertical detachment energies (VDEs) of anion clusters. There are two prerequisites when the 3D assignment method is ultilized. First, a reliable global minimum search algorithm is necessary to explore enough valleys on the potential energy surface. Second, trustworthy simulated spectra are necessary, that is to say, spectra that are in quantitative agreement. In this paper, we demonstrate the validity of the 3D assignment method using Au8M(-) (M=Si, Ge, Sn) systems. Results from this study indicate that the global minimum structures of Au8Ge(-) and Au8Sn(-) clusters are different from those described in previous studies.

  2. Jet Stream Converges Prior to 6.8M Niigata Chuetsu-oki Earthquake of Japan on 2007/07/16

    NASA Astrophysics Data System (ADS)

    Wu, H.

    2007-12-01

    The 6.8M Niigata Chuetsu-oki earthquake occurred on 2007/07/16 and resulted in 11 deaths and at least 1000 injuries have been reported, and 342 buildings were completely destroyed. The 108km/hr isobar jet stream line converged around an epicenter on 2007/07/01 12:00 and 2007/07/02 06:00. Before a devastating earthquake occurs, the underground water level usually changes caused by the rock squishing or loosening. This study assumed that rock squishing or loosening caused air inhalation or exhalation that creates an internal gravity wave. This phenomenon will change the jet streams at an altitude of 10 km. Ps. The predicted Data:07/06/26-07/07/26 Japan(37.4N140.0E)M 6.0 100% The Actual Data: 07/07/16 Japan (37.576N138.469E) 6.6M 10km This earthquake prediction had been predicted on http://tw.myblog.yahoo.com/wu10002002/ and sent to Dr. Dimitar Ouzounov in advance.

  3. Effects of the A-site cation number on the properties of Ln5/8M3/8MnO 3 manganites

    NASA Astrophysics Data System (ADS)

    Collado, J. A.; García-Muñoz, J. L.; Aranda, M. A. G.

    2010-05-01

    The properties of manganites can be tuned by changing the doping level x in Ln1-xM xMnO 3. A second mechanism allows tuning of magnetic and electronic properties, for fixed x values, by varying the average A-cation radius, < r A>. Moreover, for fixed x and < r A> values, the changes in the A-cation size variance, σ2, also modify the ferromagnetic and metal-insulator transition temperatures. Here, we investigate the influence of the number of A-site cations on Ln5/8M3/8MnO 3 manganites, where x, < r A> and σ2 values are kept constant, and in the absence of phase separation phenomena. We have found that the number of cation species at the A site ( N A) has a strong influence on the width of the ferromagnetic and metal-insulator transitions, and a small influence on the average transition temperature. This behavior is opposite to that observed for increasing values of the variance σ2 in manganites, with the same x and < r A> values, where average transition temperatures are strongly reduced.

  4. Magnetodielectric effects in A -site cation-ordered chromate spinels Li M C r4O8 (M =Ga and In)

    NASA Astrophysics Data System (ADS)

    Saha, Rana; Fauth, Francois; Avdeev, Maxim; Kayser, Paula; Kennedy, Brendan J.; Sundaresan, A.

    2016-08-01

    We report the occurrence of a magnetodielectric effect and its correlation with structure and magnetism in the A -site ordered chromate spinel oxides Li M C r4O8 (M =Ga , In). In addition to magnetic and dielectric measurements, temperature dependent synchrotron and neutron diffraction experiments have been carried out for the Ga compound. The results are compared and contrasted with that of a corresponding conventional B -site magnetic chromate spinel oxide, ZnC r2O4 . Like ZnC r2O4 , the A -site ordered chromate spinels exhibit a magnetodielectric effect at the magnetic ordering temperature (TN˜13 -15 K ), resulting from magnetoelastic coupling through a spin Jahn-Teller effect. While the presence of a broad magnetic anomaly, associated with a short-range magnetic ordering (TSO˜45 K ) in ZnC r2O4 , does not cause any dielectric anomaly, a sharp change in dielectric constant has been observed in LiInC r4O8 at the magnetic anomaly, which is associated with the opening of a spin gap (TSG˜60 K ). Contrary to the In compound, a broad dielectric anomaly exists at the onset of short-range antiferromagnetic ordering (TSO˜55 K ) in LiGaC r4O8 . The differences in dielectric behavior of these compounds have been discussed in terms of breathing distortion of the C r4 tetrahedra.

  5. Three-Dimensional Assignment of the Structures of Atomic Clusters: an Example of Au8M (M=Si, Ge, Sn) Anion Clusters

    NASA Astrophysics Data System (ADS)

    Liu, Yi-Rong; Huang, Teng; Gai, Yan-Bo; Zhang, Yang; Feng, Ya-Juan; Huang, Wei

    2015-12-01

    Identification of different isomer structures of atomic and molecular clusters has long been a challenging task in the field of cluster science. Here we present a three-dimensional (3D) assignment method, combining the energy (1D) and simulated (2D) spectra to assure the assignment of the global minimum structure. This method is more accurate and convenient than traditional methods, which only consider the total energy and first vertical detachment energies (VDEs) of anion clusters. There are two prerequisites when the 3D assignment method is ultilized. First, a reliable global minimum search algorithm is necessary to explore enough valleys on the potential energy surface. Second, trustworthy simulated spectra are necessary, that is to say, spectra that are in quantitative agreement. In this paper, we demonstrate the validity of the 3D assignment method using Au8M- (M = Si, Ge, Sn) systems. Results from this study indicate that the global minimum structures of Au8Ge- and Au8Sn- clusters are different from those described in previous studies.

  6. Large-scale, low-cost synthesis of monodispersed gold nanorods using a gemini surfactant

    NASA Astrophysics Data System (ADS)

    Xu, Yong; Zhao, Yang; Chen, Lei; Wang, Xuchun; Sun, Jianxia; Wu, Haihua; Bao, Feng; Fan, Jian; Zhang, Qiao

    2015-04-01

    In this work, we demonstrate that monodispersed gold nanorods (AuNRs) can be obtained in a large-scale and cost-effective way. By using an industrial grade gemini surfactant (P16-8-16), the cost of the synthesis of high-quality AuNRs can be significantly reduced by 90%. The synthesis can be scaled up to over 4 L. The aspect ratio of AuNRs can be well tuned from ~2.4 to ~6.3, resulting in a wide tunability of the SPR properties. Systematic studies reveal that P16-8-16 could have a dual function: it can not only act as a capping ligand to stabilize AuNRs but also it can pre-reduce Au3+ to Au+ by the unsaturated C&z.dbd;C bond. Furthermore, the shape of AuNRs can be tailored from straight nanorods to ``dog-bones'' by simply varying the concentration of the surfactant. A mechanistic study shows that the shape change can be attributed to the presence of excess bromide ions because of the complex effect between bromide ions and gold ions. This work will not only help to achieve the industrial production of AuNRs, but also promote research into practical applications of various nanomaterials.In this work, we demonstrate that monodispersed gold nanorods (AuNRs) can be obtained in a large-scale and cost-effective way. By using an industrial grade gemini surfactant (P16-8-16), the cost of the synthesis of high-quality AuNRs can be significantly reduced by 90%. The synthesis can be scaled up to over 4 L. The aspect ratio of AuNRs can be well tuned from ~2.4 to ~6.3, resulting in a wide tunability of the SPR properties. Systematic studies reveal that P16-8-16 could have a dual function: it can not only act as a capping ligand to stabilize AuNRs but also it can pre-reduce Au3+ to Au+ by the unsaturated C&z.dbd;C bond. Furthermore, the shape of AuNRs can be tailored from straight nanorods to ``dog-bones'' by simply varying the concentration of the surfactant. A mechanistic study shows that the shape change can be attributed to the presence of excess bromide ions because of the

  7. Time variability of Neptune's horizontal and vertical cloud structure revealed by VLT/SINFONI and Gemini/NIFS from 2009 to 2013

    NASA Astrophysics Data System (ADS)

    Irwin, P. G. J.; Fletcher, L. N.; Tice, D.; Owen, S. J.; Orton, G. S.; Teanby, N. A.; Davis, G. R.

    2016-06-01

    New observations of Neptune's clouds in the near infrared were acquired in October 2013 with SINFONI on ESO's Very Large Telescope (VLT) in Chile. SINFONI is an Integral Field Unit spectrometer returning a 64 × 64 pixel image with 2048 wavelengths. Image cubes in the J-band (1.09-1.41 μm) and H-band (1.43-1.87 μm) were obtained at spatial resolutions of 0.1″and 0.025″per pixel, while SINFONI's adaptive optics provided an effective resolution of approximately 0.1″. Image cubes were obtained at the start and end of three successive nights to monitor the temporal development of discrete clouds both at short timescales (i.e. during a single night) as well as over the longer period of the three-day observing run. These observations were compared with similar H-band observations obtained in September 2009 with the NIFS Integral Field Unit spectrometer on the Gemini-North telescope in Hawaii, previously reported by Irwin et al. (2011) [Icarus, 216, 141-158], and previously unreported Gemini/NIFS observations at lower spatial resolution made in 2011. We find both similarities and differences between these observations, spaced over four years. The same overall cloud structure is seen with high, bright clouds visible at mid-latitudes (30-40°N,S), with slightly lower clouds observed at lower latitudes, together with small discrete clouds seen circling the pole at a latitude of approximately 60°S. However, while discrete clouds were visible at this latitude at both the main cloud deck level (at 2-3 bar) and in the upper troposphere (100-500 mb) in 2009, no distinct deep (2-3 bar), discrete circumpolar clouds were visible in 2013, although some deep clouds were seen at the southern edge of the main cloud belt at 30-40°S, which have not been observed before. The nature of the deep sub-polar discrete clouds observed in 2009 is intriguing. While it is possible that in 2013 these deeper clouds were masked by faster moving, overlying features, we consider that it is

  8. A comprehensive study on micellization of dissymmetric pyrrolidinium headgroup-based gemini surfactants.

    PubMed

    Zou, Min; Dong, Jinfeng; Yang, Guangfu; Li, Xuefeng

    2015-04-21

    Three groups of pyrrolidinium headgroup-based gemini surfactants of 1,1'-(propane-1,3-diyl)bis(1-alkyl pyrrolidinium) bromide, in categories of symmetric CmC3CmPB (m = 10, 12, 14), dissymmetric CmC3C14PB (m = 10, 12, 14) and CmC3CnPB (m = 8, 10, 12, m + n = 24) surfactants, are studied using equilibrium surface tension, conductivity, fluorescence, and NMR techniques. The importance of the dissymmetry on the micellization has been revealed in detail. The increase in the hydrophobic chain length m for CmC3CmPB and CmC3C14PB or in the dissymmetry (n/m) for CmC3CnPB can strengthen the aggregation ability and surface activity of the surfactants significantly, i.e., a lower critical micelle concentration (cmc) and a lower surface tension at cmc (γcmc). However, the aggregation number at cmc (N*) obeys the opposite variation tendency and it becomes smaller upon increasing m or n/m, due to the formation of premicelles. Thermodynamic results reveal that the contribution of enthalpy (ΔH) to the Gibbs free energy (ΔG) is strengthened by increasing m or n/m during the spontaneous micellization process. Moreover, (1)H NMR results confirm the microenvironment change of the surfactants from polar water to micelles during the micellization, and 2D Noesy NMR spectra suggest that the methylene groups in the ring should adopt a conformation toward the nonpolar micellar core rather than in the polar water.

  9. DETECTABILITY OF EXOPLANETS IN THE {beta} PIC MOVING GROUP WITH THE GEMINI PLANET IMAGER

    SciTech Connect

    Kataria, Tiffany; Simon, Michal

    2010-07-15

    We model the detectability of exoplanets around stars in the {beta} Pic Moving Group (BPMG) using the Gemini Planet Imager (GPI), a coronagraphic instrument designed to detect companions by imaging. Members of the BPMG are considered promising targets for exoplanet searches because of their youth ({approx}12 Myr) and proximity (median distance {approx}35 pc). We wrote a modeling procedure to generate hypothetical companions of given mass, age, eccentricity, and semi-major axis, and place them around BPMG members that fall within the V-band range of the GPI. We count companions lying within the GPI's field of view and H-band fluxes that have a host-companion flux ratio placing them within its sensitivity as possible detections. The fraction of companions that could be detected depends on their brightness at 12 Myr, and hence formation mechanism, and on their distribution of semi-major axes. We used brightness models for formation by disk instability and core-accretion. We considered the two extreme cases of the semi-major axis distribution-the log-normal distribution of the nearby F- and G-type stars and a power-law distribution indicated by the exoplanets detected by the radial velocity technique. We find that the GPI could detect exoplanets of all the F and G spectral type stars in the BPMG sample with a probability that depends on the brightness model and semi-major axis distribution. At spectral type K-M1, exoplanet detectability depends on brightness and hence distance of the host star. GPI will be able to detect the companions of M stars later than M1 only if they are closer than 10 pc. Of the four A stars in the BPMG sample, only one has a V-band brightness in the range of GPI; the others are too bright.

  10. Gemini Planet Imager Observations of the AU Microscopii Debris Disk: Asymmetries within One Arcsecond

    NASA Astrophysics Data System (ADS)

    Wang, Jason J.; Graham, James R.; Pueyo, Laurent; Nielsen, Eric L.; Millar-Blanchaer, Max; De Rosa, Robert J.; Kalas, Paul; Ammons, S. Mark; Bulger, Joanna; Cardwell, Andrew; Chen, Christine; Chiang, Eugene; Chilcote, Jeffrey K.; Doyon, René; Draper, Zachary H.; Duchêne, Gaspard; Esposito, Thomas M.; Fitzgerald, Michael P.; Goodsell, Stephen J.; Greenbaum, Alexandra Z.; Hartung, Markus; Hibon, Pascale; Hinkley, Sasha; Hung, Li-Wei; Ingraham, Patrick; Larkin, James E.; Macintosh, Bruce; Maire, Jerome; Marchis, Franck; Marois, Christian; Matthews, Brenda C.; Morzinski, Katie M.; Oppenheimer, Rebecca; Patience, Jenny; Perrin, Marshall D.; Rajan, Abhijith; Rantakyrö, Fredrik T.; Sadakuni, Naru; Serio, Andrew; Sivaramakrishnan, Anand; Soummer, Rémi; Thomas, Sandrine; Ward-Duong, Kimberly; Wiktorowicz, Sloane J.; Wolff, Schuyler G.

    2015-10-01

    We present Gemini Planet Imager (GPI) observations of AU Microscopii, a young M dwarf with an edge-on, dusty debris disk. Integral field spectroscopy and broadband imaging polarimetry were obtained during the commissioning of GPI. In our broadband imaging polarimetry observations, we detect the disk only in total intensity and find asymmetries in the morphology of the disk between the southeast (SE) and northwest (NW) sides. The SE side of the disk exhibits a bump at 1″ (10 AU projected separation) that is three times more vertically extended and three times fainter in peak surface brightness than the NW side at similar separations. This part of the disk is also vertically offset by 69 ± 30 mas to the northeast at 1″ when compared to the established disk midplane and is consistent with prior Atacama Large Millimeter/submillimeter Array and Hubble Space Telescope/Space Telescope Imaging Spectrograph observations. We see hints that the SE bump might be a result of detecting a horizontal sliver feature above the main disk that could be the disk backside. Alternatively, when including the morphology of the NW side, where the disk midplane is offset in the opposite direction ∼50 mas between 0.″4 and 1.″2, the asymmetries suggest a warp-like feature. Using our integral field spectroscopy data to search for planets, we are 50% complete for ∼4 MJup planets at 4 AU. We detect a source, resolved only along the disk plane, that could either be a candidate planetary mass companion or a compact clump in the disk.

  11. Gemini Planet Imager observations of the AU Microscopii debris disk: Asymmetries within one arcsecond

    SciTech Connect

    Wang, Jason J.; Graham, James R.; Pueyo, Laurent; Nielsen, Eric L.; Millar-Blanchaer, Max; De Rosa, Robert J.; Kalas, Paul; Ammons, S. Mark; Bulger, Joanna; Cardwell, Andrew; Chen, Christine; Chiang, Eugene; Chilcote, Jeffrey K.; Doyon, René; Draper, Zachary H.; Duchêne, Gaspard; Fitzgerald, Michael P.; Goodsell, Stephen J.; Greenbaum, Alexandra Z.; Hartung, Markus; Hibon, Pascale; Hinkley, Sasha; Hung, Li -Wei; Ingraham, Patrick; Larkin, James E.; Macintosh, Bruce; Maire, Jerome; Marchis, Franck; Marois, Christian; Matthews, Brenda C.; Morzinski, Katie M.; Oppenheimer, Rebecca; Patience, Jenny; Perrin, Marshall D.; Rajan, Abhijith; Rantakyrö, Fredrik T.; Sadakuni, Naru; Serio, Andrew; Sivaramakrishnan, Anand; Soummer, Rémi; Thomas, Sandrine; Ward-Duong, Kimberly; Wiktorowicz, Sloane J.; Wolff, Schuyler G.

    2015-09-23

    We present Gemini Planet Imager (GPI) observations of AU Microscopii, a young M dwarf with an edge-on, dusty debris disk. Integral field spectroscopy and broadband imaging polarimetry were obtained during the commissioning of GPI. In our broadband imaging polarimetry observations, we detect the disk only in total intensity and find asymmetries in the morphology of the disk between the southeast (SE) and northwest (NW) sides. The SE side of the disk exhibits a bump at 1'' (10 AU projected separation) that is three times more vertically extended and three times fainter in peak surface brightness than the NW side at similar separations. This part of the disk is also vertically offset by 69 ± 30 mas to the northeast at 1'' when compared to the established disk midplane and is consistent with prior Atacama Large Millimeter/submillimeter Array and Hubble Space Telescope/Space Telescope Imaging Spectrograph observations. We see hints that the SE bump might be a result of detecting a horizontal sliver feature above the main disk that could be the disk backside. Alternatively, when including the morphology of the NW side, where the disk midplane is offset in the opposite direction ~50 mas between 0farcs4 and 1farcs2, the asymmetries suggest a warp-like feature. Using our integral field spectroscopy data to search for planets, we are 50% complete for ~4 MJup planets at 4 AU. Lastly, we detect a source, resolved only along the disk plane, that could either be a candidate planetary mass companion or a compact clump in the disk.

  12. Gemini Planet Imager observations of the AU Microscopii debris disk: Asymmetries within one arcsecond

    DOE PAGES

    Wang, Jason J.; Graham, James R.; Pueyo, Laurent; Nielsen, Eric L.; Millar-Blanchaer, Max; De Rosa, Robert J.; Kalas, Paul; Ammons, S. Mark; Bulger, Joanna; Cardwell, Andrew; et al

    2015-09-23

    We present Gemini Planet Imager (GPI) observations of AU Microscopii, a young M dwarf with an edge-on, dusty debris disk. Integral field spectroscopy and broadband imaging polarimetry were obtained during the commissioning of GPI. In our broadband imaging polarimetry observations, we detect the disk only in total intensity and find asymmetries in the morphology of the disk between the southeast (SE) and northwest (NW) sides. The SE side of the disk exhibits a bump at 1'' (10 AU projected separation) that is three times more vertically extended and three times fainter in peak surface brightness than the NW side atmore » similar separations. This part of the disk is also vertically offset by 69 ± 30 mas to the northeast at 1'' when compared to the established disk midplane and is consistent with prior Atacama Large Millimeter/submillimeter Array and Hubble Space Telescope/Space Telescope Imaging Spectrograph observations. We see hints that the SE bump might be a result of detecting a horizontal sliver feature above the main disk that could be the disk backside. Alternatively, when including the morphology of the NW side, where the disk midplane is offset in the opposite direction ~50 mas between 0farcs4 and 1farcs2, the asymmetries suggest a warp-like feature. Using our integral field spectroscopy data to search for planets, we are 50% complete for ~4 MJup planets at 4 AU. Lastly, we detect a source, resolved only along the disk plane, that could either be a candidate planetary mass companion or a compact clump in the disk.« less

  13. Interactions of cationic trimeric, gemini and monomeric surfactants with trianionic curcumin in aqueous solution.

    PubMed

    Wang, Meina; Wu, Chunxian; Tang, Yongqiang; Fan, Yaxun; Han, Yuchun; Wang, Yilin

    2014-05-21

    Interactions of trianionic curcumin (Cur(3-)) with a series of cationic surfactants, monomeric surfactant dodecyl trimethylammonium bromide (DTAB), dimeric surfactant hexamethylene-1,6-bis(dodecyldimethylammonium bromide) (12-6-12) and trimeric surfactant tri(dodecyldimethylammonioacetoxy)diethyltriamine trichloride (DTAD), have been investigated in aqueous solution of pH 13.0. Surface tension and spectral measurements indicate that the cationic surfactants display a similar surfactant concentration dependent interaction process with Cur(3-), involving three interaction stages. At first the three cationic surfactants electrostatically bind on Cur(3-) to form the surfactant-Cur(3-) complex. Then the bound and unbound cationic surfactants with Cur(3-) aggregate into surfactant-Cur(3-) mixed micelles through hydrophobic interactions above the critical micelle concentration of the surfactants (CMCC) in the presence of Cur(3-). Finally excess unbound surfactants self-assemble into micelles like those without Cur(3-). For all the three surfactants, the addition of Cur(3-) only decreases the critical micelle concentration of 12-6-12 but does not affect the critical micelle concentration of DTAB and DTAD. As the oligomeric degree of surfactants increases, the intermolecular interaction of the cationic surfactants with Cur(3-) increases and the surfactant amount needed for Cur(3-) encapsulation decreases. Compared with 12-6-12, either the weaker interaction of DTAB with Cur(3-) or stronger interaction of DTAD with Cur(3-) limits the stability or solubility of Cur(3-) in surfactant micelles. Therefore, gemini surfactant 12-6-12 is the best choice to effectively suppress Cur(3-) degradation at very low concentrations. Isothermal titration microcalorimetry, surface tension and (1)H NMR results reveal that 12-6-12 and Cur(3-) form a (12-6-12)2-Cur(3-) complex and start to form micelles at extremely decreased concentrations, where either 12-6-12 or Cur(3-) works as a bridge

  14. Shocks and star formation in Stephan's Quintet. I. Gemini spectroscopy of Hα-bright knots

    SciTech Connect

    Konstantopoulos, I. S.; Cluver, M. E.; Appleton, P. N.; Guillard, P.; Trancho, G.; Bastian, N.; Charlton, J. C.; Fedotov, K.; Gallagher, S. C.; Smith, L. J.; Struck, C. J.

    2014-03-20

    We present a Gemini-GMOS spectroscopic study of Hubble Space Telescope (HST)-selected Hα-emitting regions in Stephan's Quintet (HCG 92), a nearby compact galaxy group, with the aim of disentangling the processes of shock-induced heating and star formation in its intra-group medium. The ≈40 sources are distributed across the system, but most densely concentrated in the ∼kiloparsec-long shock region. Their spectra neatly divide them into narrow- and broad-line emitters, and we decompose the latter into three or more emission peaks corresponding to spatial elements discernible in HST imaging. The emission-line ratios of the two populations of Hα-emitters confirm their nature as H II regions (90% of the sample) or molecular gas heated by a shock front propagating at ≲300 km s{sup –1}. Their redshift distribution reveals interesting three-dimensional structure with respect to gas-phase baryons, with no H II regions associated with shocked gas, no shocked regions in the intruder galaxy NGC 7318B, and a sharp boundary between shocks and star formation. We conclude that star formation is inhibited substantially, if not entirely, in the shock region. Attributing those H II regions projected against the shock to the intruder, we find a lopsided distribution of star formation in this galaxy, reminiscent of pileup regions in models of interacting galaxies. The Hα luminosities imply mass outputs, star formation rates, and efficiencies similar to nearby star-forming regions. Two large knots are an exception to this, being comparable in stellar output to the prolific 30 Doradus region. We also examine Stephan's Quintet in the context of compact galaxy group evolution, as a paradigm for intermittent star formation histories in the presence of a rich, X-ray-emitting intra-group medium. All spectra are provided as supplemental materials.

  15. Gemini North Multi-Object Spectrograph (GMOS-N) CCDs Upgrade: Project Status and Future Plans

    NASA Astrophysics Data System (ADS)

    Kleinman, Scot; Hardy, T.; Murowinski, R.; Szeto, K.; Walls, B.; Roth, K.; Chiboucas, K.; Schiavon, R.; Gimeno, G.; White, J.; Simons, D.; Rippa, M.; Labrie, K.; Dunn, J.; Hanna, K.; Cavedoni, C.; Bombino, S.

    2012-01-01

    The GMOS-N CCDs have been recently upgraded with new e2v deep-depletion devices, replacing the original EEV CCDs in use since the instrument was commissioned in late 2001. These new detectors have improved sensitivity in both the red and the blue, and were immediately used for queue observing while commissioning and detector on-sky characterization proceeded in parallel. These devices provide an incremental, yet significant upgrade which will be followed by the planned replacement of the focal plane with fully-depleted Hamamatsu red and blue sensitive devices. The interim e2v upgrade was designed to satisfy the needs of the Gemini scientific community in a timely fashion until issues encountered with the Hamamatsu CCD upgrade could be more fully addressed. Here, we present a project status update on the GMOS-N CCDs upgrade project, including details of the e2v deep-depletion CCD installation and plans for the eventual Hamamatsu upgrade. We discuss some of the complications and lessons learned during the course of the Hamamatsu project, and present the current schedule for installation of the Hamamatsu CCDs. In addition to further improved QE in the red, the Hamamatsu project will deliver faster readout times, 10% more spectral coverage, and improved detector controller software providing integrated support for nod & shuffle. By combining multiple CCDs with different anti-reflective coatings, the coming Hamamatsu focal plane array will retain the increased blue sensitivity recently realized by the e2V installation and provide an additional factor of 2 increase in QE longward of 940 nm.

  16. The Gemini NICI planet-finding campaign: the orbit of the young exoplanet β Pictoris b

    SciTech Connect

    Nielsen, Eric L.; Liu, Michael C.; Chun, Mark; Ftaclas, Christ; Wahhaj, Zahed; Biller, Beth A.; Hayward, Thomas L.; Kuchner, Marc J.; Rodigas, Timothy J.; Toomey, Douglas W.

    2014-10-20

    We present new astrometry for the young (12-21 Myr) exoplanet β Pictoris b taken with the Gemini/NICI and Magellan/MagAO instruments between 2009 and 2012. The high dynamic range of our observations allows us to measure the relative position of β Pic b with respect to its primary star with greater accuracy than previous observations. Based on a Markov Chain Monte Carlo analysis, we find the planet has an orbital semi-major axis of 9.1{sub −0.5}{sup +5.3} AU and orbital eccentricity <0.15 at 68% confidence (with 95% confidence intervals of 8.2-48 AU and 0.00-0.82 for semi-major axis and eccentricity, respectively, due to a long narrow degenerate tail between the two). We find that the planet has reached its maximum projected elongation, enabling higher precision determination of the orbital parameters than previously possible, and that the planet's projected separation is currently decreasing. With unsaturated data of the entire β Pic system (primary star, planet, and disk) obtained thanks to NICI's semi-transparent focal plane mask, we are able to tightly constrain the relative orientation of the circumstellar components. We find the orbital plane of the planet lies between the inner and outer disks: the position angle (P.A.) of nodes for the planet's orbit (211.8 ± 0.°3) is 7.4σ greater than the P.A. of the spine of the outer disk and 3.2σ less than the warped inner disk P.A., indicating the disk is not collisionally relaxed. Finally, for the first time we are able to dynamically constrain the mass of the primary star β Pic to 1.76{sub −0.17}{sup +0.18} M {sub ☉}.

  17. Spectroscopic Characterization of HD 95086 b with the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    De Rosa, Robert J.; Rameau, Julien; Patience, Jenny; Graham, James R.; Doyon, René; Lafrenière, David; Macintosh, Bruce; Pueyo, Laurent; Rajan, Abhijith; Wang, Jason J.; Ward-Duong, Kimberly; Hung, Li-Wei; Maire, Jérôme; Nielsen, Eric L.; Ammons, S. Mark; Bulger, Joanna; Cardwell, Andrew; Chilcote, Jeffrey K.; Galvez, Ramon L.; Gerard, Benjamin L.; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Johnson-Groh, Mara; Kalas, Paul; Konopacky, Quinn M.; Marchis, Franck; Marois, Christian; Metchev, Stanimir; Morzinski, Katie M.; Oppenheimer, Rebecca; Perrin, Marshall D.; Rantakyrö, Fredrik T.; Savransky, Dmitry; Thomas, Sandrine

    2016-06-01

    We present new H (1.5-1.8 μm) photometric and K 1 (1.9-2.2 μm) spectroscopic observations of the young exoplanet HD 95086 b obtained with the Gemini Planet Imager. The H-band magnitude has been significantly improved relative to previous measurements, whereas the low-resolution K 1 (λ /δ λ ≈ 66) spectrum is featureless within the measurement uncertainties and presents a monotonically increasing pseudo-continuum consistent with a cloudy atmosphere. By combining these new measurements with literature L\\prime photometry, we compare the spectral energy distribution (SED) of the planet to other young planetary-mass companions, field brown dwarfs, and to the predictions of grids of model atmospheres. HD 95086 b is over a magnitude redder in {K}1-L\\prime color than 2MASS J12073346-3932539 b and HR 8799 c and d, despite having a similar L\\prime magnitude. Considering only the near-infrared measurements, HD 95086 b is most analogous to the brown dwarfs 2MASS J2244316+204343 and 2MASS J21481633+4003594, both of which are thought to have dusty atmospheres. Morphologically, the SED of HD 95086 b is best fit by low temperature ({T}{{eff}} = 800-1300 K), low surface gravity spectra from models which simulate high photospheric dust content. This range of effective temperatures is consistent with field L/T transition objects, but the spectral type of HD 95086 b is poorly constrained between early L and late T due to its unusual position the color-magnitude diagram, demonstrating the difficulty in spectral typing young, low surface gravity substellar objects. As one of the reddest such objects, HD 95086 b represents an important empirical benchmark against which our current understanding of the atmospheric properties of young extrasolar planets can be tested.

  18. GEMINI PLANET IMAGER OBSERVATIONS OF THE AU MICROSCOPII DEBRIS DISK: ASYMMETRIES WITHIN ONE ARCSECOND

    SciTech Connect

    Wang, Jason J.; Graham, James R.; De Rosa, Robert J.; Kalas, Paul; Chiang, Eugene; Duchêne, Gaspard; Pueyo, Laurent; Chen, Christine; Greenbaum, Alexandra Z.; Nielsen, Eric L.; Millar-Blanchaer, Max; Ammons, S. Mark; Bulger, Joanna; Cardwell, Andrew; Goodsell, Stephen J.; Chilcote, Jeffrey K.; Doyon, René; Draper, Zachary H.; Esposito, Thomas M.; Fitzgerald, Michael P.; and others

    2015-10-01

    We present Gemini Planet Imager (GPI) observations of AU Microscopii, a young M dwarf with an edge-on, dusty debris disk. Integral field spectroscopy and broadband imaging polarimetry were obtained during the commissioning of GPI. In our broadband imaging polarimetry observations, we detect the disk only in total intensity and find asymmetries in the morphology of the disk between the southeast (SE) and northwest (NW) sides. The SE side of the disk exhibits a bump at 1″ (10 AU projected separation) that is three times more vertically extended and three times fainter in peak surface brightness than the NW side at similar separations. This part of the disk is also vertically offset by 69 ± 30 mas to the northeast at 1″ when compared to the established disk midplane and is consistent with prior Atacama Large Millimeter/submillimeter Array and Hubble Space Telescope/Space Telescope Imaging Spectrograph observations. We see hints that the SE bump might be a result of detecting a horizontal sliver feature above the main disk that could be the disk backside. Alternatively, when including the morphology of the NW side, where the disk midplane is offset in the opposite direction ∼50 mas between 0.″4 and 1.″2, the asymmetries suggest a warp-like feature. Using our integral field spectroscopy data to search for planets, we are 50% complete for ∼4 M{sub Jup} planets at 4 AU. We detect a source, resolved only along the disk plane, that could either be a candidate planetary mass companion or a compact clump in the disk.

  19. GRB 150101B: Confirmation of a fading optical counterpart

    NASA Astrophysics Data System (ADS)

    Fong, Wen-fai; Berger, Edo; Fox, Derek; Shappee, Ben

    2015-01-01

    We re-observed the field of the short/soft GRB 150101B (Cummings, GCN #17267) with the Gemini Multi-Object Spectrograph (GMOS) mounted on the Gemini-South 8-m telescope starting on 2015 Jan 12.326 UT, 10.7 days after the BAT trigger and 9.0 days after our initial Magellan observations (Fong et al., GCN #17271).

  20. Reaching the Diffraction Limit - Differential Speckle and Wide-Field Imaging for the Gemini-N Telescope

    NASA Technical Reports Server (NTRS)

    Scott, Nic J.; Howell, Steve; Horch, Elliott

    2016-01-01

    Speckle imaging allows telescopes to achieve di raction limited imaging performance. The technique requires cameras capable of reading out frames at a very fast rate, e ectively `freezing out' atmospheric seeing. The resulting speckles can be correlated and images reconstructed that are at the di raction limit of the telescope. These new instruments are based on the successful performance and design of the Di erential Speckle Survey Instrument (DSSI) [2, 1]. The instruments are being built for the Gemini-N and WIYN telescopes and will be made available to the community via the peer review proposal process. We envision their primary use to be validation and characterization of exoplanet targets from the NASA K2 and TESS missions and RV discovered exoplanets. Such targets will provide excellent follow-up candidates for both the WIYN and Gemini telescopes [3]. Examples of DSSI data are shown in the gures below. We expect similar data quality in speckle imaging mode with the new instruments. Additionally, both cameras will have a wide- eld mode and standard SDSS lters. They will be highly versatile instruments and it is that likely many other science programs will request time on the cameras. The limiting magnitude for speckle observations, will remain around 13-14th at WIYN and 16-17th at Gemini, while wide- eld, normal CCD imaging operation should be able to go to much fainter, providing usual CCD imaging and photometric capabilities. The instruments will also have high utility as scoring cameras for telescope engineering purposes, or other applications where high time resolution is needed. Instrument support will be provided, including a software pipeline that takes raw speckle data to fully reconstructed images.

  1. View looking south from pavilion, showing south entrance house, south ...

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

    View looking south from pavilion, showing south entrance house, south wing, and engine house - Fairmount Waterworks, East bank of Schuylkill River, Aquarium Drive, Philadelphia, Philadelphia County, PA

  2. Chromospheric activity on the late-type star V1355 Ori using Lijiang 1.8-m and 2.4-m telescopes

    NASA Astrophysics Data System (ADS)

    Pi, Qing-Feng; Zhang, Li-Yun; Chang, Liang; Han, Xian-Ming; Lu, Hong-Peng; Zhang, Xi-Liang; Wang, Dai-Mei

    2016-10-01

    We obtained new high-resolution spectra using the Lijiang 1.8-m and 2.4-m telescopes to investigate the chromospheric activities of V1355 Ori as indicated in the behaviors of Ca ii H&K, Hδ, Hγ, Hβ, Na i D1, D2, Hα and Ca ii infrared triplet (IRT) lines. The observed spectra show obvious emissions above the continuum in Ca ii H&K lines, absorptions in the Hδ, Hγ, Hβ and Na i D1, D2 lines, variable behavior (filled-in absorption, partial emission with a core absorption component or emission above the continuum) in the Hα line, and weak self-reversal emissions in the strong filled-in absorptions of the Ca ii IRT lines. We used a spectral subtraction technique to analyze our data. The results show no excess emission in the Hδ and Hγ lines, very weak excess emissions in the Na i D1, D2 lines, excess emission in the Hβ line, clear excess emission in the Hα line, and excess emissions in the Ca ii IRT lines. The value of the ratio of EW8542/EW8498 is in the range 0.9 to 1.7, which implies that chromospheric activity might have been caused by plage events. The value of the ratio E Hα/E Hβ is above 3, indicating that the Balmer lines would arise from prominence-like material. We also found time variations in light curves associated with equivalent widths of chromospheric activity lines in the Na i D1, D2, Ca ii IRT and Hα lines in particular. These phenomena can be explained by plage events, which are consistent with the behavior of chromospheric activity indicators.

  3. Effect of cation site-disorder on the structure and magneto-transport properties of Ln5/8M3/8MnO 3 manganites

    NASA Astrophysics Data System (ADS)

    Collado, J. A.; Frontera, C.; García-Muñoz, J. L.; Aranda, M. A. G.

    2005-06-01

    Five members of Ln5/8M3/8MnO 3 series with A-cation size variance ( σ2) ranging between 3×10 -4 and 71×10 -4 Å 2, and the same A-cation size =1.2025 Å, have been synthesized by the ceramic method. The five manganites are single phase and they crystallize in the Pnma perovskite superstructure. The five compositions display ferromagnetic-paramagnetic transitions at temperatures ranging between 130 and 270 K, for the highest and lowest variance sample, respectively. The samples with smaller variances show sharp magnetization transitions and the samples with the larger variances display broad transitions. These transitions have also been studied by differential scanning calorimetry, DSC, and some enthalpy changes are reported. The resistivity study indicates that all samples display the expected metal-to-insulator transitions at temperatures ranging between 140 and 270 K. The samples have been analysed at room temperature by ultra-high-resolution synchrotron powder diffraction and the structural and microstructural features are reported. Furthermore, Nd 5/8Sr 0.255Ca 0.12MnO 3 ( σ2=40×10-4 Å2) and Sm 0.225Nd 0.4Sr 0.308Ca 0.067MnO 3 ( σ2=53×10-4 Å2) samples have also been studied by synchrotron powder diffraction at 140 K, below the transition temperatures. Both samples are found to be single phase above and below the transition by ultra-high-resolution synchrotron powder diffraction. The microstructure of the samples has been investigated through Williamson-Hall plots. Sample broadenings are markedly anisotropic and strongly dominated by microstrains with average values of the Δ d/ d term close to 14×10 -4. A direct correlation is found between the microstrain values and the widths of the magnetization transitions.

  4. Microwave-assisted modification on montmorillonite with ester-containing Gemini surfactant and its adsorption behavior for triclosan.

    PubMed

    Liu, Bo; Lu, Junxiang; Xie, Yu; Yang, Bin; Wang, Xiaoying; Sun, Runcang

    2014-03-15

    To obtain effective adsorbent that can remove emerging organic pollutant of triclosan (TCS) in aquatic environment, different ester-containing Gemini surfactant-modified MMT (EMMT) were prepared under microwave irradiation. The whole process was rapid, uniform, easy and energy-efficient. The structures and morphology of EMMT were characterized by XRD, TEM, FT-IR, SEM and TGA. The results revealed that the saturated intercalation amount of this surfactant was 0.8 times to cation exchange capacity (CEC) of MMT, and there was electrostatic interaction between ester-containing Gemini surfactant and MMT. In addition, they bound in the ways of intercalation, intercalation-adsorption or adsorption, which relied on the dosage of the surfactant. The surface of EMMT was hydrophobic, rough and fluffy, which contributed to its strong adsorption capacity. The adsorption equilibrium data of EMMT for TCS were fitted to Langmuir and Freundlich isothermal adsorption model. The result showed that Langmuir isothermal adsorption model could describe the adsorption behavior better, the adsorption behavior of TCS on EMMT was confirmed to a surface monolayer adsorption, and notably the theoretical maximum adsorption capacity was up to 133 mg/g. Therefore, this work lays important foundation on developing effective and safe absorbent materials for the treatment of emerging organic pollutants.

  5. FLAMINGOS-2: the facility near-infrared wide-field imager and multi-object spectrograph for Gemini

    NASA Astrophysics Data System (ADS)

    Eikenberry, Stephen; Elston, Richard; Raines, S. Nicholas; Julian, Jeff; Hanna, Kevin; Warner, Craig; Julian, Roger; Bandyopadhyay, Reba; Bennett, J. Greg; Bessoff, Aaron; Branch, Matt; Corley, Richard; Dewitt, Curtis; Eriksen, John-David; Frommeyer, Skip; Gonzalez, Anthony; Herlevich, Michael; Hon, David; Marin-Franch, Antonio; Marti, Jose; Murphey, Charlie; Rambold, William; Rashkin, David; Leckie, Brian; Gardhouse, W. Rusty; Fletcher, Murray; Hardy, Tim; Dunn, Jennifer; Wooff, Robert

    2008-07-01

    We report on the design and status of the FLAMINGOS-2 instrument - a fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048×2048-pixel HAWAII-2 0.9-2.4 μm detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined plates or 3 long slits for spectroscopy over a 6×2-arcminute field of view, and selectable grisms provide resolutions from ~1300 to ~3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi- Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3×1-arcminute field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On- Instrument WaveFront Sensor subsystems. We also present the current status of the project and future plans, including on-sky delivery planned for late 2008.

  6. FLAMINGOS-2: the facility near-infrared wide-field imager and multi-object spectrograph for Gemini

    NASA Astrophysics Data System (ADS)

    Eikenberry, Stephen; Bandyopadhyay, Reba; Bennett, J. Greg; Bessoff, Aaron; Branch, Matt; Charcos, Miguel; Corley, Richard; Dewitt, Curtis; Eriksen, John-David; Elston, Richard; Frommeyer, Skip; Gonzalez, Anthony; Hanna, Kevin; Herlevich, Michael; Hon, David; Julian, Jeff; Julian, Roger; Lasso, Nestor; Marin-Franch, Antonio; Marti, Jose; Murphey, Charlie; Raines, S. N.; Rambold, William; Rashkind, David; Warner, Craig; Leckie, Brian; Gardhouse, W. R.; Fletcher, Murray; Hardy, Tim; Dunn, Jennifer; Wooff, Robert; Pazder, John

    2012-09-01

    We report on the design, on-sky performance, and status of the FLAMINGOS-2 instrument - the fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048x2048- pixel HAWAII-2 0.9-2.4 μm detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined plates or 3 long slits for spectroscopy over a 6x2-arcminute field of view, and selectable grisms provide resolutions from ~1300 to ~3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi-Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3x1-arcminute field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On-Instrument WaveFront Sensor subsystems. We also present the on-sky performance measured during acceptance testing in 2009, as well as current status of the project and future plans.

  7. Microwave-assisted modification on montmorillonite with ester-containing Gemini surfactant and its adsorption behavior for triclosan.

    PubMed

    Liu, Bo; Lu, Junxiang; Xie, Yu; Yang, Bin; Wang, Xiaoying; Sun, Runcang

    2014-03-15

    To obtain effective adsorbent that can remove emerging organic pollutant of triclosan (TCS) in aquatic environment, different ester-containing Gemini surfactant-modified MMT (EMMT) were prepared under microwave irradiation. The whole process was rapid, uniform, easy and energy-efficient. The structures and morphology of EMMT were characterized by XRD, TEM, FT-IR, SEM and TGA. The results revealed that the saturated intercalation amount of this surfactant was 0.8 times to cation exchange capacity (CEC) of MMT, and there was electrostatic interaction between ester-containing Gemini surfactant and MMT. In addition, they bound in the ways of intercalation, intercalation-adsorption or adsorption, which relied on the dosage of the surfactant. The surface of EMMT was hydrophobic, rough and fluffy, which contributed to its strong adsorption capacity. The adsorption equilibrium data of EMMT for TCS were fitted to Langmuir and Freundlich isothermal adsorption model. The result showed that Langmuir isothermal adsorption model could describe the adsorption behavior better, the adsorption behavior of TCS on EMMT was confirmed to a surface monolayer adsorption, and notably the theoretical maximum adsorption capacity was up to 133 mg/g. Therefore, this work lays important foundation on developing effective and safe absorbent materials for the treatment of emerging organic pollutants. PMID:24461850

  8. A gemini quaternary ammonium poly (ether ether ketone) anion-exchange membrane for alkaline fuel cell: design, synthesis, and properties.

    PubMed

    Si, Jiangju; Lu, Shanfu; Xu, Xin; Peng, Sikan; Xiu, Ruijie; Xiang, Yan

    2014-12-01

    To reconcile the tradeoff between conductivity and dimensional stability in AEMs, a novel Gemini quaternary ammonium poly (ether ether ketone) (GQ-PEEK) membrane was designed and successfully synthesized by a green three-step procedure that included polycondensation, bromination, and quaternization. Gemini quaternary ammonium cation groups attached to the anti-swelling PEEK backbone improved the ionic conductivity of the membranes while undergoing only moderate swelling. The grafting degree (GD) of the GQ-PEEK significantly affected the properties of the membranes, including their ion-exchange capacity, water uptake, swelling, and ionic conductivity. Our GQ-PEEK membranes exhibited less swelling (≤ 40 % at 25-70 °C, GD 67 %) and greater ionic conductivity (44.8 mS cm(-1) at 75 °C, GD 67 %) compared with single quaternary ammonium poly (ether ether ketone). Enhanced fuel cell performance was achieved when the GQ-PEEK membranes were incorporated into H2 /O2 single cells. PMID:25346412

  9. pH-induced motion control of self-propelled oil droplets using a hydrolyzable gemini cationic surfactant.

    PubMed

    Miura, Shingo; Banno, Taisuke; Tonooka, Taishi; Osaki, Toshihisa; Takeuchi, Shoji; Toyota, Taro

    2014-07-15

    Self-propelled motion of micrometer-sized substances has drawn much attention as an autonomous transportation system. One candidate vehicle is a chemically driven micrometer-sized oil droplet. However, to the best of our knowledge, there has been no report of a chemical reaction system controlling the three-dimensional motion of oil droplets underwater. In this study, we developed a molecular system that controlled the self-propelled motion of 4-heptyloxybenzaldehyde oil droplets by using novel gemini cationic surfactants containing carbonate linkages (2G12C). We found that, in emulsions containing sodium hydroxide, the motion time of the self-propelled oil droplets was longer in the presence of 2G12C than in the presence of gemini cationic surfactants without carbonate linkages. Moreover, in 2G12C solution, oil droplets at rest underwent unidirectional, self-propelled motion in a gradient field toward a higher concentration of sodium hydroxide. Even though they stopped within several seconds, they restarted in the same direction. 2G12C was gradually hydrolyzed under basic conditions to produce a pair of the corresponding monomeric surfactants, which exhibit different interfacial properties from 2G12C. The prolonged and restart motion of the oil droplets were explained by the increase in the heterogeneity of the interfacial tension of the oil droplets.

  10. High Precision Lightcurves of A Mutual Event of Transneptunian Binary (79360) Sila-Nunam From Gemini Observatory

    NASA Astrophysics Data System (ADS)

    Verbiscer, Anne J.; Grundy, W.; Benecchi, S.; Rabinowitz, D.; Skrutskie, M. F.

    2013-10-01

    Cold-classical Kuiper Belt binary (79360) Sila-Nunam is in the midst of a decade-long mutual event season in which its nearly equal-sized components occult and eclipse each other as viewed from Earth (Grundy et al. 2012 Icarus 220, 74-83). On 14 February 2013 UT, the Gemini Multi-Object Spectrograph (GMOS-N) camera at Gemini Observatory on Mauna Kea, Hawai'i imaged nearly an entire inferior event in which Nunam, the smaller of the two objects, eclipsed and occulted Sila. Alternating 200-second exposures in Sloan r' and i' filters continuously during the 9.3-hour event produced lightcurves containing information about sizes, colors, shapes, and albedo patterns on the system components. This mutual event is a rare opportunity to determine physical characteristics of a surface which has likely been unaltered since the time of Solar System formation. A. Verbiscer acknowledges support from NASA Planetary Astronomy. W. Grundy acknowledges support from NSF Planetary Astronomy.

  11. Gemini North/NIRI Spectra of Pluto and Charon: Simultaneous Analysis of the Surface and Atmosphere

    NASA Astrophysics Data System (ADS)

    Cook, Jason C.; Cruikshank, Dale P.; Young, Leslie A.

    2014-11-01

    We report on our analysis of blended Pluto and Charon spectra over the wavelength range 1.4 to 2.5 μm as obtained by the NIRI instrument on Gemini North on June 25-28, 2004. The data have a resolving power (λ/Δλ) around 1500 and a SNR around 200 per pixel. The observed blended spectra are compared to models that combine absorption from the solid ice on the surface using Hapke theory, and absorption from the gaseous atmosphere. We assume the spectrum is a combination of several spatially separate spectral units: a CH4-rich ice unit, a volatile unit (an intimate mixture of N2, CH4 and CO), and a Charon unit (H2O, ammonia hydrate and kaolinite). We test for the presence of hydrocarbons (i.e. C2H6) and nitriles (i.e. HCN) and examine cases where additional ices are present as either pure separate spatial units, mixed with the CH4-rich unit or part of the volatile unit. We conclude that 2-4% of Pluto’s surface is covered with pure-C2H6 ice and our identification of solid C2H6 is significantly strengthened when absorption due to gaseous CH4 is included. The inclusion of Pluto’s atmosphere demonstrates that low-resolution, high-SNR observations are capable of detecting Pluto’s atmosphere during a time when Pluto’s atmosphere may have been undergoing rapid changes (1988-2002) and no high-resolution spectra were obtained. In particular, we identify features at 1.665 and 2.317 μm as the Q-branch of the 2ν3 and ν3+ν4 bands of gaseous CH4, respectively. The later band is also evident in many previously published spectra of Pluto. Our analysis finds it is unnecessary to include 13CO to explain the depth of the 2.405 μm, which has been previously suggested to be a spectral blended with C2H6, but we cannot definitively rule out its presence.Funding for this work has been provided by NASA-PATM grant NNX12AK62G.

  12. THE GEMINI PLANET-FINDING CAMPAIGN: THE FREQUENCY OF GIANT PLANETS AROUND DEBRIS DISK STARS

    SciTech Connect

    Wahhaj, Zahed; Liu, Michael C.; Nielsen, Eric L.; Ftaclas, Christ; Chun, Mark; Biller, Beth A.; Hayward, Thomas L.; Thatte, Niranjan; Tecza, Matthias; Shkolnik, Evgenya L.; Kuchner, Marc; Reid, I. Neill; De Gouveia Dal Pino, Elisabete M.; Gregorio-Hetem, Jane; Boss, Alan; Lin, Douglas N. C.; and others

    2013-08-20

    We have completed a high-contrast direct imaging survey for giant planets around 57 debris disk stars as part of the Gemini NICI Planet-Finding Campaign. We achieved median H-band contrasts of 12.4 mag at 0.''5 and 14.1 mag at 1'' separation. Follow-up observations of the 66 candidates with projected separation <500 AU show that all of them are background objects. To establish statistical constraints on the underlying giant planet population based on our imaging data, we have developed a new Bayesian formalism that incorporates (1) non-detections, (2) single-epoch candidates, (3) astrometric and (4) photometric information, and (5) the possibility of multiple planets per star to constrain the planet population. Our formalism allows us to include in our analysis the previously known {beta} Pictoris and the HR 8799 planets. Our results show at 95% confidence that <13% of debris disk stars have a {>=}5 M{sub Jup} planet beyond 80 AU, and <21% of debris disk stars have a {>=}3 M{sub Jup} planet outside of 40 AU, based on hot-start evolutionary models. We model the population of directly imaged planets as d {sup 2} N/dMda{proportional_to}m {sup {alpha}} a {sup {beta}}, where m is planet mass and a is orbital semi-major axis (with a maximum value of a{sub max}). We find that {beta} < -0.8 and/or {alpha} > 1.7. Likewise, we find that {beta} < -0.8 and/or a{sub max} < 200 AU. For the case where the planet frequency rises sharply with mass ({alpha} > 1.7), this occurs because all the planets detected to date have masses above 5 M{sub Jup}, but planets of lower mass could easily have been detected by our search. If we ignore the {beta} Pic and HR 8799 planets (should they belong to a rare and distinct group), we find that <20% of debris disk stars have a {>=}3 M{sub Jup} planet beyond 10 AU, and {beta} < -0.8 and/or {alpha} < -1.5. Likewise, {beta} < -0.8 and/or a{sub max} < 125 AU. Our Bayesian constraints are not strong enough to reveal any dependence of the planet

  13. Gemini Planet Imager Exoplanet Survey: Key Results Two Years Into The Survey

    NASA Astrophysics Data System (ADS)

    Marchis, Franck; Rameau, Julien; Nielsen, Eric L.; De Rosa, Robert J.; Esposito, Thomas; Draper, Zachary H.; Macintosh, Bruce; Graham, James R.; GPIES

    2016-10-01

    The Gemini Planet Imager Exoplanet Survey (GPIES) is targeting 600 young, nearby stars using the GPI instrument. We report here on recent results obtained with this instrument from our team.Rameau et al. (ApJL, 822 2, L2, 2016) presented astrometric monitoring of the young exoplanet HD 95086 b obtained with GPI between 2013 and 2016. Efficient Monte Carlo techniques place preliminary constraints on the orbital parameters of HD 95086 b. Under the assumption of a coplanar planet–disk system, the periastron of HD 95086 b is beyond 51 AU. Therefore, HD 95086 b cannot carve the entire gap inferred from the measured infrared excess in the SED of HD 95086. Additional photometric and spectroscopic measurements reported by de Rosa et al. (2016, apJ, in press) showed that the spectral energy distribution of HD 95086 b is best fit by low temperature (T~800-1300 K), low surface gravity spectra from models which simulate high photospheric dust content. Its temperature is typical to L/T transition objects, but the spectral type is poorly constrained. HD 95086 b is an important exoplanet to test our models of atmospheric properties of young extrasolar planets.Direct detections of debris disk are keys to infer the collisional past and understand the formation of planetary systems. Two debris disks were recently studied with GPI:- Draper et al. (submitted to ApJ, 2016) show the resolved circumstellar debris disk around HD 111520 at a projected range of ~30-100 AU using both total and polarized H-band intensity. Structures in the disks such as a large brightness asymmetry and symmetric polarization fraction are seen. Additional data would confirm if a large disruption event from a stellar fly-by or planetary perturbations altered the disk density- Esposito et al. (submitted to ApJ, 2016) combined Keck NIRC2 data taken at 1.2-2.3 microns and GPI 1.6 micron total intensity and polarized light detections that probes down to projected separations less than 10 AU to show that the HD

  14. Gemini NorthNIRI Spectra of Pluto and Charon: Simultaneous Analysis of the Surface and Atmosphere

    NASA Technical Reports Server (NTRS)

    Cook, Jason C.; Cruikshank, Dale P.; Young, Leslie A.

    2014-01-01

    94035We report on our analysis of blended Pluto and Charon spectra over the wavelength range 1.4 to 2.5 m as obtained by the NIRI instrument on Gemini North on June 25-28, 2004. The data have a resolving power () around 1500 and a SNR around 200 per pixel. The observed blended spectra are compared to models that combine absorption from the solid ice on the surface using Hapke theory, and absorption from the gaseous atmosphere. We assume the spectrum is a combination of several spatially separate spectral units: a CH4-rich ice unit, a volatile unit (an intimate mixture of N2, CH4 and CO), and a Charon unit (H2O, ammonia hydrate and kaolinite). We test for the presence of hydrocarbons (i.e. C2H6) and nitriles (i.e. HCN) and examine cases where additional ices are present as either pure separate spatial units, mixed with the CH4-rich unit or part of the volatile unit. We conclude that 2-4 of Plutos surface is covered with pure-C2H6 and our identification of C2H6 is significantly strengthened when absorption due to gaseous CH4 is included. The inclusion of Plutos atmosphere demonstrates that low-resolution, high-SNR observations are capable of detecting Plutos atmosphere during a time when Plutos atmosphere may have been undergoing rapid changes (1988-2002) and no high-resolution spectra were obtained. In particular, we identify features at 1.665 and 2.317 m as the Q-branch of the 23 and 3+4 bands of gaseous CH4, respectively. The later band is also evident in many previously published spectra of Pluto. Our analysis finds it is unnecessary to include 13CO to explain the depth of the 2.405 m, which has been previously suggested to be a spectral blended with C2H6, but we cannot definitively rule out its presence. Funding for this work (Cook) has been provided by a NASA-PATM grant.

  15. Gemini and Keck Observations of Slowly Rotating, Bilobate Active Asteroid (300163)

    NASA Astrophysics Data System (ADS)

    Waniak, Waclaw; Drahus, Michal

    2016-10-01

    One of the most puzzling questions regarding Active Asteroids is the mechanism of their activation. While some Active Asteroids show protracted and often recurrent mass loss, consistent with seasonal ice sublimation, some other eject dust impulsively as a result of a catastrophic disruption (e.g. Jewitt et al. 2015, Asteroids IV, 221). It has been suggested that ice can be excavated from the cold near-surface interior by an impact (Hsieh & Jewitt 2006, Science 312, 561) or, for small objects susceptible to YORP torques, by near-critical spin rate (Sheppard & Trujillo 2014, AJ 149, 44). But impact and rapid spin can also cause a catastrophic disruption (e.g. Jewitt et al. 2015, Asteroids IV, 221). It therefore becomes apparent that the different types of mass loss observed in Active Asteroids can be best classified and understood based on the nucleus spin rates (Drahus et al. 2015, ApJL 802, L8), but unfortunately the rotation periods have been measured for a very limited number of these objects. With this in mind we have initiated a survey of light curves of small Active Asteroids on the largest ground-based optical telescopes. Here we present the results for (300163), also known as 288P and 2006 VW139, which is a small 2.6-km sized asteroid that exhibited a comet-like activity over 100 days in the second half of 2011 (Hsieh et al. 2012, ApJL 748, L15; Licandro et al. 2013, A&A 550, A17; Agarwal et al. 2016, AJ 151, 12). Using Keck/DEIMOS and Gemini/GMOS-S working in tandem on UT 2015 May 21–22 we have detected an inactive nucleus and measured a complete, dense, high-S/N rotational light curve. The light curve has a double-peaked period of 16 hours, an amplitude of 0.4 mag, and moderately narrow minima suggesting a bilobate or contact-binary shape. The long rotation period clearly demonstrates a non-rotational origin of activity of this object, consistent with an impact. Furthermore, among the five small Active Asteroids with known rotation periods (300163) is

  16. Effect of gemini (alkanediyl-α,ω-bis(dimethylcetylammonium bromide)) (16-s-16, s = 4, 5, 6) surfactants on the interaction of ninhydrin with chromium-glycylphenylalanine

    NASA Astrophysics Data System (ADS)

    Kumar, Dileep; Rub, Malik Abdul; Akram, Mohd.; Kabir-ud-Din

    2014-11-01

    The effect of gemini (alkanediyl-α,ω-bis(dimethylcetylammonium bromide)) (16-s-16, s = 4, 5, 6) surfactants on the interaction of ninhydrin with chromium(III) complex of glycylphenylalanine ([Cr(III)-Gly-Phe]2+) has been investigated using UV-visible spectrophotometer at different temperatures. The order of reaction with respect to [Cr(III)-Gly-Phe]2+ is unity while it is fractional with respect to ninhydrin. Whereas, the values of rate constant (kψ) increase and leveling-off regions, like conventional single chain cetyltrimethylammonium bromide (CTAB) surfactant, were observed with geminis, later produces a third region of increasing kψ at higher gemini surfactant concentrations. This unusual third-region effect of the gemini micelles is assigned to changes in their micellar morphologies. The results obtained in micellar media were treated in terms of pseudo-phase model. The values of thermodynamic parameters (Ea, ΔH# and ΔS#) and binding constants (KA and KNin) have been evaluated.

  17. Effect of gemini (alkanediyl-α,ω-bis(dimethylcetylammonium bromide)) (16-s-16, s=4, 5, 6) surfactants on the interaction of ninhydrin with chromium-glycylphenylalanine.

    PubMed

    Kumar, Dileep; Rub, Malik Abdul; Akram, Mohd; Kabir-ud-Din

    2014-11-11

    The effect of gemini (alkanediyl-α,ω-bis(dimethylcetylammonium bromide)) (16-s-16, s=4, 5, 6) surfactants on the interaction of ninhydrin with chromium(III) complex of glycylphenylalanine ([Cr(III)-Gly-Phe]2+) has been investigated using UV-visible spectrophotometer at different temperatures. The order of reaction with respect to [Cr(III)-Gly-Phe]2+ is unity while it is fractional with respect to ninhydrin. Whereas, the values of rate constant (kψ) increase and leveling-off regions, like conventional single chain cetyltrimethylammonium bromide (CTAB) surfactant, were observed with geminis, later produces a third region of increasing kψ at higher gemini surfactant concentrations. This unusual third-region effect of the gemini micelles is assigned to changes in their micellar morphologies. The results obtained in micellar media were treated in terms of pseudo-phase model. The values of thermodynamic parameters (Ea, ΔH# and ΔS#) and binding constants (KA and KNin) have been evaluated. PMID:24878435

  18. Evidence for a 3 X 10^8 M_⊙ Black Hole in NGC 7052 from Hubble Space Telescope Observations of the Nuclear Gas Disk

    NASA Astrophysics Data System (ADS)

    van der Marel, Roeland P.; van den Bosch, Frank C.

    1998-11-01

    We present a Hubble Space Telescope (HST) study of the nuclear region of the E4 radio galaxy NGC 7052, which has a nuclear disk of dust and gas. The Second Wide Field and Planetary Camera (WFPC2) was used to obtain B, V, and I broadband images and an Hα + [N II] narrowband image. The images yield the stellar surface brightness profile, the optical depth of the dust, and the flux distribution of the ionized gas. The Faint Object Spectrograph was used to obtain Hα + [N II] spectra at six different positions along the major axis, using a 0.26" diameter circular aperture. The emission lines yield the rotation curve of the ionized gas and the radial profile of its velocity dispersion. The observed rotation velocity at r = 0.2" from the nucleus is V = 155 +/- 17 km s^-1. The Gaussian dispersion of the emission lines increases from sigma ~ 70 km s^-1 at r = 1" to sigma ~ 400 km s^-1 on the nucleus. To interpret the gas kinematics, we construct axisymmetric models in which the gas and dust reside in a disk in the equatorial plane of the stellar body and are viewed at an inclination of 70 deg. It is assumed that the gas moves on circular orbits, with an intrinsic velocity dispersion due to turbulence (or otherwise nongravitational motion). The latter is required to fit the observed increase in the line widths toward the nucleus and must reach a value in excess of 500 km s^-1 in the central 0.1". The circular velocity is calculated from the combined gravitational potential of the stars and a possible nuclear black hole. Models without a black hole predict a rotation curve that is shallower than observed (V_pred = 92 km s^-1 at r = 0.2") and are ruled out at greater than 99% confidence. Models with a black hole of mass M_a=3.3^+2.3_-1.3x10^8 M_⊙ provide an acceptable fit. The best-fitting model with a black hole adequately reproduces the observed emission-line shapes on the nucleus, which have a narrower peak and broader wings than a Gaussian. NGC 7052 can be added to the

  19. A Gemini/GMOS study of the physical conditions and kinematics of the blue compact dwarf galaxy Mrk 996

    NASA Astrophysics Data System (ADS)

    Telles, Eduardo; Thuan, Trinh X.; Izotov, Yuri I.; Carrasco, Eleazar R.

    2014-01-01

    Aims: We present an integral field spectroscopic study with the Gemini Multi-Object Spectrograph (GMOS) of the unusual blue compact dwarf (BCD) galaxy Mrk 996. Methods: We show through velocity and dispersion maps, emission-line intensity and ratio maps, and by a new technique of electron density limit imaging that the ionization properties of different regions in Mrk 996 are correlated with their kinematic properties. Results: From the maps, we can spatially distinguish a very dense high-ionization zone with broad lines in the nuclear region, and a less dense low-ionization zone with narrow lines in the circumnuclear region. Four kinematically distinct systems of lines are identified in the integrated spectrum of Mrk 996, suggesting stellar wind outflows from a population of Wolf-Rayet (WR) stars in the nuclear region, superposed on an underlying rotation pattern. From the intensities of the blue and red bumps, we derive a population of ~473 late nitrogen (WNL) stars and ~98 early carbon (WCE) stars in the nucleus of Mrk 996, resulting in a high N(WR)/N(O+WR) of 0.19. We derive, for the outer narrow-line region, an oxygen abundance 12 + log (O/H) = 7.94 ± 0.30 (~0.2 Z⊙) by using the direct Te method derived from the detected narrow [O iii]λ4363 line. The nucleus of Mrk 996 is, however, nitrogen-enhanced by a factor of ~20, in agreement with previous CLOUDY modeling. This nitrogen enhancement is probably due to nitrogen-enriched WR ejecta, but also to enhanced nitrogen line emission in a high-density environment. Although we have made use here of two new methods - principal component analysis (PCA) tomography and a method for mapping low- and high-density clouds - to analyze our data, new methodology is needed to further exploit the wealth of information provided by integral field spectroscopy. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative

  20. Complexation of β-cyclodextrin with a gemini surfactant studied by isothermal titration microcalorimetry and surface tensiometry.

    PubMed

    Benkő, Mária; Király, László A; Puskás, Sándor; Király, Zoltán

    2014-06-17

    We report on the inclusion complex formation of β-cyclodextrin (βCD) with a cocogem surfactant (counterion-coupled gemini surfactant; (bis(4-(2-alkyl)benzenesulfonate)-Jeffamine salt, abbreviated as ABSJ), studied by isothermal titration calorimetry (ITC) and surface tension (SFT) measurements. We measured the critical micelle concentration (cmc) of ABSJ in water by the two experimental techniques in the temperature range 283-343 K, and determined the thermodynamic parameters of the complex formation directly by ITC and indirectly by the SFT. The stoichiometry (N), the binding constant (K), and the enthalpy of complexation were determined, and the Gibbs free energy and the entropy term were calculated from the experimental data. A novel method is presented for the determination of N and K by using surface tensiometry.

  1. Gemini Alkyldeoxy-D-Glucitolammonium Salts as Modern Surfactants and Microbiocides: Synthesis, Antimicrobial and Surface Activity, Biodegradation

    PubMed Central

    Brycki, Bogumił; Szulc, Adrianna

    2014-01-01

    Dimeric quaternary alkylammonium salts possess a favourable surface and antimicrobial activity. In this paper we describe synthesis, spectroscopic analysis, surface and antimicrobial activity as well as biodegradability of polymethylene-α,ω-bis(N,N-dialkyl-N-deoxy-D-glucitolammonium iodides), a new group of dimeric quaternary ammonium salts. This new group of gemini surfactants can be produced from chemicals which come from renewable sources. The structure of products has been determined by the FTIR and 1H and 13C NMR spectroscopy. The biodegradability, surface activity and antimicrobial efficacy against Escherichia coli, Staphylococcus aureus, Candida albicans, Aspergillus niger and Penicillium chrysogenum were determined. The influence of the number of alkyl chains and their lengths on surface and antimicrobial properties has been shown. In general, dimeric quaternary alkyldeoxy-D-glucitolammonium salts with long alkyl substituents show favourable surface properties and an excellent antimicrobial activity. PMID:24416314

  2. Synergistic behaviour of ZnO nanoparticles and gemini surfactants on the dynamic and equilibrium oil/water interfacial tension.

    PubMed

    Fereidooni Moghadam, Tahereh; Azizian, Saeid; Wettig, Shawn

    2015-03-21

    In this work the effect of ZnO nanoparticles on the interfacial behaviour of gemini surfactants (12-3-12 and 14-3-14) at the oil/water interface was investigated. Equilibrium and dynamic interfacial tension in the absence and presence of ZnO was measured and compared. The results show that the synergistic interactions between the surfactants and nanoparticles decrease the interfacial tension beyond that observed for each component, alone. Modelling of dynamic data with two different models indicates that the mechanism of surfactant migration (with and without ZnO) is mixed diffusion-kinetic-control. The Gibbs free energy of micellization and the Gibbs free energy of adsorption in the absence and presence of ZnO were calculated and compared. Finally the effect of addition of ZnO nanoparticles on emulsion stability was also examined.

  3. Insight into sorption mechanism of phenanthrene onto gemini modified palygorskite through a multi-level fuzzy-factorial inference approach.

    PubMed

    Zhao, Shan; Huang, Gordon; Wang, Shuo; Wang, Xiuquan; Huang, Wendy

    2016-07-28

    A multi-level fuzzy-factorial inference approach was proposed to examine the sorption behavior of phenanthrene on palygorskite modified with a gemini surfactant. Fuzzy set theory was used to determine five experimentally controlled environmental factors with triangular membership functions, including initial concentration, added humid acid dose, ionic strength, temperature, and pH. The statistical significance of factors and their interactions affecting the sorption process was revealed through a multi-level factorial experiment. Initial concentration, ionic strength, and pH were identified as the most significant factors based on the multi-way ANOVA results. Examination of curvature effects of factors revealed the nonlinear complexity inherent in the sorption process. The potential interactions among experimental factors were detected, which is meaningful for providing a deep insight into the sorption mechanisms under the influences of factors at different levels. PMID:27163726

  4. The effect of the spacer rigidity on the aggregation behavior of two ester-containing Gemini surfactants.

    PubMed

    Zhang, Zhiguo; Zheng, Peizhu; Guo, Yimin; Yang, Yan; Chen, Zhiyun; Wang, Xiaoyong; An, Xueqin; Shen, Weiguo

    2012-08-01

    Two Gemini surfactants with very similar structure but different spacer rigidity, namely 1-dodecanaminium,N,N'-[[(2E)-1,4-dioxo-2-butene-1,4-diyl]bis(oxy-2,1-ethanediyl)]bis[N,N-dimethyl-,bromide] (12-fo-12) and 1-dodecanaminium, N,N'-[(1,4-dioxo-1,4-butanediyl)bis(oxy-2,1-ethanediyl)] bis[N,N-dimethyl-, bromide] (12-su-12), and their monomeric counterpart 1-dodecanaminium, N-[2-(acetyloxy)ethyl]-N,N-dimethyl-, bromide (DTAAB) were synthesized and their aggregation behavior in aqueous solutions was studied by measurements of surface tension, conductivity, isothermal titration calorimetry, dynamic light scattering, and transmission electron microscopy. It was found that the Krafft point of 12-fo-12 was 18.6°C, significantly higher than that of 12-su-12 (7.6°C) and DTAAB (<0°C). The minimum surface areas per surfactant A(min) at the water-air interface of DTAAB, 12-su-12, and 12-fo-12 were determined. It was found that the value of A(min) of DTAAB was larger than half that of 12-su-12 but smaller than half that of 12-fo-12. The values of the degree of association β of the three surfactants were found to be in a sequence of DTAAB>12-su-12>12-fo-12, which was in accord with the sequence of the entropy of micellization. The enthalpies of micellization of the two Gemini surfactants were found to be more negative than double that of DTAAB, and 12-fo-12 had the most negative standard enthalpy of micellization. It was also found that 12-su-12 and DTAAB formed micelles in aqueous solutions, while 12-fo-12 could form micelles and vesicles dependent on the concentration.

  5. High S/N Keck and Gemini AO imaging of Uranus during 2012-2014: New cloud patterns, increasing activity, and improved wind measurements

    NASA Astrophysics Data System (ADS)

    Sromovsky, L. A.; de Pater, I.; Fry, P. M.; Hammel, H. B.; Marcus, P.

    2015-09-01

    We imaged Uranus in the near infrared from 2012 into 2014, using the Keck/NIRC2 camera and Gemini/NIRI camera, both with adaptive optics. We obtained exceptional signal to noise ratios by averaging 8-16 individual exposures in a planet-fixed coordinate system. These noise-reduced images revealed many low-contrast discrete features and large scale cloud patterns not seen before, including scalloped waveforms just south of the equator, and an associated transverse ribbon wave near 6°S. In all three years numerous small (600-700 km wide) and mainly bright discrete features were seen within the north polar region (north of about 55°N). Two small dark spots with bright companions were seen at middle latitudes. Over 850 wind measurements were made, the vast majority of which were in the northern hemisphere. Winds at high latitudes were measured with great precision, revealing an extended region of solid body rotation between 62°N and at least 83°N, at a rate of 4.08 ± 0.015°/h westward relative to the planet's interior (radio) rotation of 20.88°/h westward. Near-equatorial speeds measured with high accuracy give different results for waves and small discrete features, with eastward drift rates of 0.4°/h and 0.1°/h respectively. The region of polar solid body rotation is a close match to the region of small-scale polar cloud features, suggesting a dynamical relationship. The winds from prior years and those from 2012-2014 are consistent with a mainly symmetric wind profile up to middle latitudes, with a small asymmetric component of ∼0.09°/h peaking near ±30°, and about 60% greater amplitude if only prior years are included, suggesting a declining mid-latitude asymmetry. While winds at high southern latitudes (50-90°S) are unconstrained by groundbased observations, a recent reanalysis of 1986 Voyager 2 observations by Karkoschka (Karkoschka [2015]. Icarus 250, 294-307) has revealed an extremely large north-south asymmetry in this region, which might be

  6. [South] Korea.

    PubMed

    1987-04-01

    The Republic of Korea occupies approximately 38,000 square miles in the southern position of a mountaineous peninsula. It shares a land boundary with North Korea. With a population of more than 40 million people, South Korea has 1 of the highest population densities in the world. The language spoken is a Uralic language, closely akin to Japanese, Hungarian, Finnish, and Mongolian, and the traditional religions are Shamanism and Buddhism. Over the course of time, South Korea has been invaded and fought over by its neighbors. The US and the Soviet Union have never been able to reach a unification agreement for North and South Korea. The 3rd Republic era, begun in 1963, saw a time of rapid industrialization and a great deal of economic growth. The 5th Republic began with a new constitution and new elections brought about the election of a president to a 7-year term of office beginning in 1981. Economic growth has been remarkable over the last 25 years despite the fact that North Korea possesses most of the mineral and hydroelectric resources and the existing heavy industrial base built by the Japanese while South Korea has the limited agricultural resources and had, initially, a large unskilled labor pool. Serious industrial growth began in South Korea in the early 1960s and the GNP grew at an annual rate of 10% during the period 1963-78. Current GNP is now, at $2000, well beyond that of its neighbors to the north. The outlook for longterm growth is good; however, the military threat posed by North Korea and the absence of foreign economic assistance has resulted in Korea spending 1/3 of its budget on defense. South Korea is active in international affairs and in the UN. Economic realities have forced Korea to give economics priority in their foreign policy. There has been an on-again, off-again quality to dialogue between the 2 nations. However, the US is committed to maintaining peace on the Korean peninsula. In order to do so, they have supplied manpower and

  7. [South] Korea.

    PubMed

    1987-04-01

    The Republic of Korea occupies approximately 38,000 square miles in the southern position of a mountaineous peninsula. It shares a land boundary with North Korea. With a population of more than 40 million people, South Korea has 1 of the highest population densities in the world. The language spoken is a Uralic language, closely akin to Japanese, Hungarian, Finnish, and Mongolian, and the traditional religions are Shamanism and Buddhism. Over the course of time, South Korea has been invaded and fought over by its neighbors. The US and the Soviet Union have never been able to reach a unification agreement for North and South Korea. The 3rd Republic era, begun in 1963, saw a time of rapid industrialization and a great deal of economic growth. The 5th Republic began with a new constitution and new elections brought about the election of a president to a 7-year term of office beginning in 1981. Economic growth has been remarkable over the last 25 years despite the fact that North Korea possesses most of the mineral and hydroelectric resources and the existing heavy industrial base built by the Japanese while South Korea has the limited agricultural resources and had, initially, a large unskilled labor pool. Serious industrial growth began in South Korea in the early 1960s and the GNP grew at an annual rate of 10% during the period 1963-78. Current GNP is now, at $2000, well beyond that of its neighbors to the north. The outlook for longterm growth is good; however, the military threat posed by North Korea and the absence of foreign economic assistance has resulted in Korea spending 1/3 of its budget on defense. South Korea is active in international affairs and in the UN. Economic realities have forced Korea to give economics priority in their foreign policy. There has been an on-again, off-again quality to dialogue between the 2 nations. However, the US is committed to maintaining peace on the Korean peninsula. In order to do so, they have supplied manpower and

  8. South Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of South Africa was acquired on May 14, 2000, by NASA's Moderate-resolution Imaging Spectroradiometer, or MODIS. The image was produced using a combination of the sensor's 250-m and 500-m resolution visible wavelength bands. As part of the opening ceremony to begin the joint U.S.-South Africa SAFARI Field Experiment, NASA presented print copies of this image as GIFts to Dr. Ben Ngubane, Minister of Arts, Science and Technology, and Honorable Advocate Ngoaka Ramathlodi, Premier of the Northern Province, South Africa. The area shown in this image encompasses seven capital cities and a number of the region's distinctive geological features can be seen clearly. Toward the northern (top) central part of the image, the browns and tans comprise the Kalahari Desert of southern Botswana. The Tropic of Capricorn runs right through the heart of the Kalahari and the Botswanan capital city of Gaborone sits on the Limpopo River, southeast of the Kalahari. Along the western coastline of the continent is the country of Namibia, where the Namib Desert is framed against the sea by the Kaokoveld Mountains. The Namibian capital of Windhoek is obscured by clouds. Looking closely in the center of the image, the Orange River can be seen running from east to west, demarcating the boundary between Namibia and South Africa. On the southwestern corner of the continent is the hook-like Cape of Good Hope peninsula and Cape Town, the parliamentary capital of South Africa. Running west to east away from Cape Town are the Great Karroo Mountains. The shadow in this image conveys a sense of the very steep grade of the cliffs along the southern coast of South Africa. Port Elizabeth sits on the southeasternmost point of South Africa, and a large phytoplankton bloom can be seen in the water about 100 miles east of there. Moving northward along the east coast, the Drakensberg Mountains are visible. The two small nations of Lesotho and Swaziland are in this region, completely

  9. Interaction between dipeptide (glycyl-phenylalanine) and ninhydrin: role of CTAB and gemini (16-s-16, s=4, 5, 6) surfactant micelles.

    PubMed

    Kumar, Dileep; Rub, Malik Abdul; Akram, Mohd; Kabir-ud-Din

    2014-03-15

    The kinetics of interaction of dipeptide glycylphenylalanine (Gly-Phe) with ninhydrin have been studied by following the reaction spectrophotometrically at 70 °C and a particular pH 5.0 in the absence and presence of conventional cetyltrimethylammonium bromide (CTAB) and gemini (alkanediyl-α,ω-bis(dimethylhexadecylammonium bromide)) surfactants. The rate shows first- and fractional-order dependence on [Gly-Phe] and [ninhydrin], respectively. The surfactants were found to catalyse the reaction. Furthermore, whereas the typical rate constant (kΨ) increase and leveling-off regions are observed with geminis, just like as seen with conventional surfactants, the former produced a third region of increasing kΨ at higher concentrations. A kinetic rate law consistent with experimental results has been derived on the basis of the proposed mechanism. PMID:24461852

  10. OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. IV. OBSERVATIONS OF KEPLER, CoRoT, AND HIPPARCOS STARS FROM THE GEMINI NORTH TELESCOPE

    SciTech Connect

    Horch, Elliott P.; Howell, Steve B.; Everett, Mark E.; Ciardi, David R. E-mail: steve.b.howell@nasa.gov E-mail: ciardi@ipac.caltech.edu

    2012-12-01

    We present the results of 71 speckle observations of binary and unresolved stars, most of which were observed with the DSSI speckle camera at the Gemini North Telescope in 2012 July. The main purpose of the run was to obtain diffraction-limited images of high-priority targets for the Kepler and CoRoT missions, but in addition, we observed a number of close binary stars where the resolution limit of Gemini was used to better determine orbital parameters and/or confirm results obtained at or below the diffraction limit of smaller telescopes. Five new binaries and one triple system were discovered, and first orbits are calculated for other two systems. Several systems are discussed in detail.

  11. Laser operations at the 8-10m class telescopes Gemini, Keck, and the VLT: lessons learned, old and new challenges

    NASA Astrophysics Data System (ADS)

    Amico, Paola; Campbell, Randall D.; Christou, Julian C.

    2010-07-01

    Laser Guide Star (LGS) assisted Adaptive Optics routine operations have commenced at three of the major astronomical observatories, in 2004 (Keck) and 2006 (VLT and Gemini) respectively. Subaru is also on the verge of putting its LGS facility into operations. In this paper we concentrate on the operational aspect of the laser facilities: we discuss common problems such as weather constraints, beam collisions, aircraft avoidance and optimal telescope scheduling. We highlight important differences between the observatories, especially in view of the valuable lessons learnt. While it is true that the three observatories have made quick progress and achieved important scientific results during the first years of operations, there is much room left for improvement in terms of the efficiency that can be obtained on sky. We compare and contrast the more recently implemented LGS systems of VLT and Gemini operated in service and queue modes to the more mature LGS operation at Keck that employs classical PI scheduled observing.

  12. Facile controlled synthesis of micro/nanostructure MCrO 4 (M = Ba, Pb) by using Gemini surfactant C 12-PEG-C 12 as a soft template

    NASA Astrophysics Data System (ADS)

    Chang, Wengui; Shen, Yuhua; Xie, Anjian; Liu, Xue

    2010-04-01

    Gemini surfactants, double sodium α-sulfonic polyethylene glycol laurate (abbreviated C 12-PEG-C 12), were prepared and applied as soft templates in the controlled synthesis of BaCrO 4 and PbCrO 4 micro/nanocrystals. The template effects were investigated by adjusting the length of the spacer, using PEG400 and PEG4000, of the Gemini surfactant. The results indicated that the size and morphology of BaCrO 4 and PbCrO 4 micro/nanocrystals varied with the change in spacer length of C 12-PEG-C 12, suggesting that the different lengths of the polyethylene glycol group spacers in the Gemini surfactants played a key role in determining the size and shape of the MCrO 4 micro/nanoparticles. The dynamic process of the formation of the novel morphology BaCrO 4 crystals showed that the morphology grew from a round-bar polyhedron, to regular polyhedron, to approximate octahedron to a uniform pistachio nut shape. The growth mechanism of the BaCrO 4 micro/nanocrystals was explained that C 12-PEG-C 12 had a greater interfacial adsorption and would effectively control the shape evolution during the crystal growth, while PbCrO 4 could be explained that the Gemini surfactants can undergo liquid-crystalline phase transitions with long channels providing a soft template effect and derived the nanorods formation. Room temperature fluorescence spectra were studied and these showed that the pistachio-shaped BaCrO 4 microcrystals and PbCrO 4 nanorods possess photoactive luminescence properties with emission peaks at 470 and 549 nm, respectively.

  13. Gemini Surfactants Based on Bis-Imidazolium Alkoxy Derivatives as Effective Agents for Delivery of Nucleic Acids: A Structural and Spectroscopic Study

    PubMed Central

    Pietralik, Zuzanna; Kołodziejska, Żaneta; Weiss, Marek; Kozak, Maciej

    2015-01-01

    The success rate of gene therapy depends on the efficient transfection of genetic material into cells. The golden mean between harmlessness and high effectiveness can be provided by synthetic lipid-like molecules that are similar to the components of biological membranes. Cationic gemini surfactants are one such moiety and because of their favourable physicochemical properties (double positive electric charge, reduced toxicity, low values of critical micelle concentration), they show great potential as delivery system components for genetic material in gene therapy. The aim of this study was to investigate the process of the complexation of cationic gemini surfactants with nucleic acids: double-stranded DNA of different sizes (21 bp, ~185 bp, ~20 kbp) and siRNA (21 bp). The tested series of dicationic surfactants consists of bis-imidazolium quaternary salts with varying lengths of hydrophobic side chains (m = 5, 6, 7, 8, 9, 11, 12, 14, 16). On the basis of the data obtained by circular dichroism spectroscopy and electrophoresis, we concluded that the studied gemini surfactants with long side chains effectively bind nucleic acids at low concentrations, which leads to the formation of stable lipoplexes. Images obtained by atomic force microscopy also confirmed the formation of vesicular structures, i.e., complexes between DNA and surfactants. The cytotoxicity of selected surfactants was also tested on HeLa cells. The surfactant toxicity significantly depends on surfactant geometry (the length of hydrophobic chain). PMID:26641889

  14. Gemini Surfactants Based on Bis-Imidazolium Alkoxy Derivatives as Effective Agents for Delivery of Nucleic Acids: A Structural and Spectroscopic Study.

    PubMed

    Pietralik, Zuzanna; Kołodziejska, Żaneta; Weiss, Marek; Kozak, Maciej

    2015-01-01

    The success rate of gene therapy depends on the efficient transfection of genetic material into cells. The golden mean between harmlessness and high effectiveness can be provided by synthetic lipid-like molecules that are similar to the components of biological membranes. Cationic gemini surfactants are one such moiety and because of their favourable physicochemical properties (double positive electric charge, reduced toxicity, low values of critical micelle concentration), they show great potential as delivery system components for genetic material in gene therapy. The aim of this study was to investigate the process of the complexation of cationic gemini surfactants with nucleic acids: double-stranded DNA of different sizes (21 bp, ~185 bp, ~20 kbp) and siRNA (21 bp). The tested series of dicationic surfactants consists of bis-imidazolium quaternary salts with varying lengths of hydrophobic side chains (m = 5, 6, 7, 8, 9, 11, 12, 14, 16). On the basis of the data obtained by circular dichroism spectroscopy and electrophoresis, we concluded that the studied gemini surfactants with long side chains effectively bind nucleic acids at low concentrations, which leads to the formation of stable lipoplexes. Images obtained by atomic force microscopy also confirmed the formation of vesicular structures, i.e., complexes between DNA and surfactants. The cytotoxicity of selected surfactants was also tested on HeLa cells. The surfactant toxicity significantly depends on surfactant geometry (the length of hydrophobic chain).

  15. Gemini Surfactants Based on Bis-Imidazolium Alkoxy Derivatives as Effective Agents for Delivery of Nucleic Acids: A Structural and Spectroscopic Study.

    PubMed

    Pietralik, Zuzanna; Kołodziejska, Żaneta; Weiss, Marek; Kozak, Maciej

    2015-01-01

    The success rate of gene therapy depends on the efficient transfection of genetic material into cells. The golden mean between harmlessness and high effectiveness can be provided by synthetic lipid-like molecules that are similar to the components of biological membranes. Cationic gemini surfactants are one such moiety and because of their favourable physicochemical properties (double positive electric charge, reduced toxicity, low values of critical micelle concentration), they show great potential as delivery system components for genetic material in gene therapy. The aim of this study was to investigate the process of the complexation of cationic gemini surfactants with nucleic acids: double-stranded DNA of different sizes (21 bp, ~185 bp, ~20 kbp) and siRNA (21 bp). The tested series of dicationic surfactants consists of bis-imidazolium quaternary salts with varying lengths of hydrophobic side chains (m = 5, 6, 7, 8, 9, 11, 12, 14, 16). On the basis of the data obtained by circular dichroism spectroscopy and electrophoresis, we concluded that the studied gemini surfactants with long side chains effectively bind nucleic acids at low concentrations, which leads to the formation of stable lipoplexes. Images obtained by atomic force microscopy also confirmed the formation of vesicular structures, i.e., complexes between DNA and surfactants. The cytotoxicity of selected surfactants was also tested on HeLa cells. The surfactant toxicity significantly depends on surfactant geometry (the length of hydrophobic chain). PMID:26641889

  16. Relationship of axonal voltage-gated sodium channel 1.8 (NaV1.8) mRNA accumulation to sciatic nerve injury-induced painful neuropathy in rats.

    PubMed

    Ruangsri, Supanigar; Lin, Audrey; Mulpuri, Yatendra; Lee, Kyung; Spigelman, Igor; Nishimura, Ichiro

    2011-11-18

    Painful peripheral neuropathy is a significant clinical problem; however, its pathological mechanism and effective treatments remain elusive. Increased peripheral expression of tetrodotoxin-resistant voltage-gated sodium channel 1.8 (NaV1.8) has been shown to associate with chronic pain symptoms in humans and experimental animals. Sciatic nerve entrapment (SNE) injury was used to develop neuropathic pain symptoms in rats, resulting in increased NaV1.8 mRNA in the injured nerve but not in dorsal root ganglia (DRG). To study the role of NaV1.8 mRNA in the pathogenesis of SNE-induced painful neuropathy, NaV1.8 shRNA vector was delivered by subcutaneous injection of cationized gelatin/plasmid DNA polyplex into the rat hindpaw and its subsequent retrograde transport via sciatic nerve to DRG. This in vivo NaV1.8 shRNA treatment reversibly and repeatedly attenuated the SNE-induced pain symptoms, an effect that became apparent following a distinct lag period of 3-4 days and lasted for 4-6 days before returning to pretreatment levels. Surprisingly, apparent knockdown of NaV1.8 mRNA occurred only in the injured nerve, not in the DRG, during the pain alleviation period. Levels of heteronuclear NaV1.8 RNA were unaffected by SNE or shRNA treatments, suggesting that transcription of the Scn10a gene encoding NaV1.8 was unchanged. Based on these data, we postulate that increased axonal mRNA transport results in accumulation of functional NaV1.8 protein in the injured nerve and the development of painful neuropathy symptoms. Thus, targeted delivery of agents that interfere with axonal NaV1.8 mRNA may represent effective neuropathic pain treatments. PMID:21965668

  17. Neutron reflectometry of quaternary gemini surfactants as a function of alkyl chain length: anomalies arising from ion association and premicellar aggregation.

    PubMed

    Li, Pei Xun; Dong, Chu Chuan; Thomas, Robert K; Penfold, J; Wang, Yilin

    2011-03-15

    We have measured the structure and properties of a series of dicationic quaternary ammonium compounds α,ω-bis(N-alkyl dimethyl ammonium)hexane halides (Cn-C6-Cn) for values of the alkyl chain length n of 8, 9, 10, 11, 12, and 16, and a series of α,ω-bis(N-alkyl dimethyl ammonium)diethylether halides (Cn-C2OC2-Cn) for values of n of 8, 12, and 16, as well as C8-C12-C8 and C12-C10-C12 at the air/water interface. Although the critical micelle concentration (CMC) in the two series decreases in the normal way, that is, logarithmically, with increasing chain length, the limiting surface tension at the CMC and the limiting area per molecule both increase with chain length, in the opposite direction from comparable single chain surfactants. The structures of the surface layers, which were determined by neutron reflectometry, indicate that the anomalous behavior of the surface tension and area are probably caused by poor packing of the gemini side chains between adjacent molecules. Comparison of the directly determined surface coverage using neutron reflectometry and the apparent coverage determined by application of the Gibbs equation to surface tension data gives an experimental measurement of the prefactor in the Gibbs equation, which should be 3 for these geminis. It was found to vary from about 3 for the two C16 geminis down to about 1.5 for the two C8 geminis. We have devised a simple quantitative model that explains this variation and earlier observations that the Gibbs prefactor for C12-Cn-C12 (n varying from 3 to 12) is around 2. The model is consistent with the conductivity, NMR, and fluorescence measurements of other authors. This model shows that both dimerization and ion association are required to explain the surface tension behavior of cationic gemini bromide surfactants and that, in many cases, the prefactor itself varies with concentration.

  18. Molecular investigation of the interaction between ionic liquid type gemini surfactant and lysozyme: A spectroscopic and computational approach.

    PubMed

    Maurya, Jitendra Kumar; Mir, Muzaffar Ul Hassan; Singh, Upendra Kumar; Maurya, Neha; Dohare, Neeraj; Patel, Seema; Ali, Anwar; Patel, Rajan

    2015-07-01

    Herein, we are reporting the interaction of ionic liquid type gemini surfactant, 1,4-bis(3-dodecylimidazolium-1-yl) butane bromide ([C12-4-C12 im]Br2) with lysozyme by using Steady state fluorescence, UV-visible, Time resolved fluorescence, Fourier transform-infrared (FT-IR) spectroscopy techniques in combination with molecular modeling and docking method. The steady state fluorescence spectra suggested that the fluorescence of lysozyme was quenched by [C12-4-C12 im]Br2 through static quenching mechanism as confirmed by time resolved fluorescence spectroscopy. The binding constant for lysozyme-[C12-4-C12 im]Br2 interaction have been measured by UV-visible spectroscopy and found to be 2.541 × 10(5) M(-1). The FT-IR results show conformational changes in the secondary structure of lysozyme by the addition of [C12-4-C12 im]Br2. Moreover, the molecular docking study suggested that hydrogen bonding and hydrophobic interactions play a key role in the protein-surfactant binding. Additionally, the molecular dynamic simulation results revealed that the lysozyme-[C12-4-C12 im]Br2 complex reaches an equilibrium state at around 3 ns.

  19. Unique Phase Behaviors in the Gemini Surfactant/EAN Binary System: The Role of the Hydroxyl Group.

    PubMed

    Li, Qintang; Wang, Xudong; Yue, Xiu; Chen, Xiao

    2015-12-22

    The hydroxyl group in the spacer of a cationic Gemini surfactant (12-3OH-12) caused dramatic changes of the phase behaviors in a protic ionic liquid (EAN). Here, the effects of the hydroxyl group on micellization and lyotropic liquid crystal formation were investigated through the surface tension, small-angle X-ray scattering, polarized optical microscopy, and rheological measurements. With the hydroxyl group in the spacer, the critical micellization concentration of 12-3OH-12 was found to be lower than that of the homologue without hydroxyl (12-3-12) and the 12-3OH-12 molecules packed more densely at the air/EAN interface. It was then interesting to observe a coexistence of two separated phases at wide concentration and temperature ranges in this 12-3OH-12/EAN system. Such a micellar phase separation was rarely observed in the ionic surfactant binary system. With the increase of surfactant concentration, the reverse hexagonal and bicontinuous cubic phases appeared in sequence, whereas only a reverse hexagonal phase was found in 12-3-12/EAN system. But, the hexagonal phases formed with 12-3OH-12 exhibited lower viscoelasticity and thermostability than those observed in 12-3-12/EAN system. Such unique changes in phase behaviors of 12-3OH-12 were ascribed to their enhanced solvophilic interactions of 12-3OH-12 and relatively weak solvophobic interactions in EAN.

  20. FIRST SCATTERED-LIGHT IMAGE OF THE DEBRIS DISK AROUND HD 131835 WITH THE GEMINI PLANET IMAGER

    SciTech Connect

    Hung, Li-Wei; Arriaga, Pauline; Fitzgerald, Michael P.; Esposito, Thomas M.; Duchêne, Gaspard; Kalas, Paul G.; De Rosa, Robert J.; Graham, James R.; Maire, Jérôme; Chilcote, Jeffrey K.; Marois, Christian; Millar-Blanchaer, Maxwell A.; Bruzzone, Sebastian; Rajan, Abhijith; Pueyo, Laurent; Wolff, Schuyler G.; Chen, Christine H.; Konopacky, Quinn; Ammons, S. Mark; Draper, Zachary H.; and others

    2015-12-10

    We present the first scattered-light image of the debris disk around HD 131835 in the H band using the Gemini Planet Imager. HD 131835 is a ∼15 Myr old A2IV star at a distance of ∼120 pc in the Sco-Cen OB association. We detect the disk only in polarized light and place an upper limit on the peak total intensity. No point sources resembling exoplanets were identified. Compared to its mid-infrared thermal emission,  in scattered light the disk shows similar orientation but different morphology. The scattered-light disk extends from ∼75 to ∼210 AU in the disk plane with roughly flat surface density. Our Monte Carlo radiative transfer model can describe the observations with a model disk composed of a mixture of silicates and amorphous carbon. In addition to the obvious brightness asymmetry due to stronger forward scattering, we discover a weak brightness asymmetry along the major axis, with the northeast side being 1.3 times brighter than the southwest side at a 3σ level.

  1. PEERING INTO THE GIANT-PLANET-FORMING REGION OF THE TW HYDRAE DISK WITH THE GEMINI PLANET IMAGER

    SciTech Connect

    Rapson, Valerie A.; Kastner, Joel H.; Millar-Blanchaer, Maxwell A.; Dong, Ruobing

    2015-12-20

    We present Gemini Planet Imager (GPI) adaptive optics near-infrared images of the giant-planet-forming regions of the protoplanetary disk orbiting the nearby (D = 54 pc), pre-main-sequence (classical T Tauri) star TW Hydrae. The GPI images, which were obtained in coronagraphic/polarimetric mode, exploit starlight scattered off small dust grains to elucidate the surface density structure of the TW Hya disk from ∼80 AU to within ∼10 AU of the star at ∼1.5 AU resolution. The GPI polarized intensity images unambiguously confirm the presence of a gap in the radial surface brightness distribution of the inner disk. The gap is centered near ∼23 AU, with a width of ∼5 AU and a depth of ∼50%. In the context of recent simulations of giant-planet formation in gaseous, dusty disks orbiting pre-main-sequence stars, these results indicate that at least one young planet with a mass ∼0.2 M{sub J} could be present in the TW Hya disk at an orbital semimajor axis similar to that of Uranus. If this (proto)planet is actively accreting gas from the disk, it may be readily detectable by GPI or a similarly sensitive, high-resolution infrared imaging system.

  2. The synthesis and structure of gemini QASs of 1,4:3,6-dianhydro-L-iditol

    NASA Astrophysics Data System (ADS)

    Sikora, Karol; Nowacki, Andrzej; Sikorski, Artur; Dmochowska, Barbara

    2015-12-01

    New, efficient, straightforward method of synthesizing quaternary diammonium salts of 1,4:3,6-dianhydro-L-iditol have been developed. This paper presents the synthesis and structural analysis of diammonium (gemini) salts, including their X-ray diffraction analysis, wherein the linking structure of nitrogen atoms consists of two fused furanoid rings. 1,4:3,6-dianhydro-2,5-di-O-triflyl-D-mannitol and four tertiary amines, i.e., 4-(N,N-dimethylamino)pyridine (DMAP), pyridine, trimethylamine and N,N-dimethyloctylamine, were used for the synthesis. All the syntheses were carried out under mild conditions by the direct nucleophilic displacement of the O-triflil group by the amine. Walden inversion of configuration at C2 and C5 atoms has occurred during the reaction, giving products with L-ido configuration. Furthermore, NMR and X-ray conformational analysis of 1,4:3,6-dianhydrohexitol residue was done. In most cases furanoid rings adopt the twisted conformation both in the crystal and in solution.

  3. FRD in optical fibres at low temperatures: investigations for Gemini's Wide-field Fibre Multi-Object Spectrograph

    NASA Astrophysics Data System (ADS)

    de Oliveira, A. C.; de Oliveira, L. S.; Dos Santos, J. B.; Arruda, M. V.; Dos Santos, L. G. C.; Rodrigues, F.; de Castro, F. L. F.

    2011-06-01

    While there is no direct evidence for the deterioration in Focal Ratio Degradation (FRD) of optical fibres in severe temperature gradients, the fibre ends inserted into metallic containment devices such as steel ferrules can be a source of stress, and hence increased FRD at low temperatures. In such conditions, instruments using optical fibres may suffer some increase in FRD and consequent loss of system throughput when they are working in environments with significant thermal gradients, a common characteristic of ground-based observatories. In this paper we present results of experiments with optical fibres inserted in different materials as a part of our prototyping study for Gemini's Wide-field Multi-Object Spectrograph (WFMOS) project. Thermal effects and the use of new holding techniques will be discussed in the context of Integral Field Units and multi-fibres systems. In this work, we have used careful methodologies that give absolute measurements of FRD to quantify the advantages of using epoxy-based composites rather than metals as support structures for the fibre ends. This is shown to be especially important in minimizing thermally induced stresses in the fibre terminations. Not only is this important for optimizing fibre spectrograph performance but the benefits of using such materials are demonstrated in the minimization of positional variations and the avoidance of metal-to-glass delamination. Furthermore, by impregnating the composites with small zirconium oxide particles the composite materials supply their own fine polishing grit which aids significantly to the optical quality of the finished product.

  4. FURTHER EVIDENCE OF THE PLANETARY NATURE OF HD 95086 b FROM GEMINI/NICI H-BAND DATA

    SciTech Connect

    Meshkat, T.; Kenworthy, M.; Bailey, V.; Su, K. Y. L.; Rameau, J.; Chauvin, G.; Lagrange, A.-M.; Boccaletti, A.; Mamajek, E. E.; Currie, T.

    2013-10-01

    We present our analysis of the Gemini/NICI H-band data of HD 95086, following the discovery of the planet HD 95086 b in L'. The H-band data reach a contrast of 12.7 mag relative to the host star at 5σ levels in the location of HD 95086 b, and no point source is found. Our non-detection and H – L' color limit rules out the possibility that the object is a foreground L/T dwarf and that, if it is bound to HD 95086, it is a genuine planetary mass object. We estimate a new pre-main-sequence isochronal age for HD 95086 of 17 ± 4 Myr, which is commensurate with previous mean age estimates for the Lower Cen-Crux subgroup. Adopting an age of 17 Myr, the color limit is inconsistent with the COND model, marginally consistent with the BT-SETTL model, and consistent with the DUSTY model.

  5. THE GEMINI NICI PLANET-FINDING CAMPAIGN: DISCOVERY OF A MULTIPLE SYSTEM ORBITING THE YOUNG A STAR HD 1160

    SciTech Connect

    Nielsen, Eric L.; Liu, Michael C.; Wahhaj, Zahed; Bowler, Brendan; Kraus, Adam; Chun, Mark; Ftaclas, Christ; Biller, Beth A.; Hayward, Thomas L.; Shkolnik, Evgenya L.; Tecza, Matthias; Clarke, Fraser; Close, Laird M.; Hartung, Markus; Males, Jared R.; Skemer, Andrew J.; Reid, I. Neill; Alencar, Silvia H. P.; Burrows, Adam; and others

    2012-05-01

    We report the discovery of two low-mass companions to the young A0V star HD 1160 at projected separations of 81 {+-} 5 AU (HD 1160 B) and 533 {+-} 25 AU (HD 1160 C) by the Gemini NICI Planet-Finding Campaign. Very Large Telescope images of the system taken over a decade for the purpose of using HD 1160 A as a photometric calibrator confirm that both companions are physically associated. By comparing the system to members of young moving groups and open clusters with well-established ages, we estimate an age of 50{sup +50}{sub -40} Myr for HD 1160 ABC. While the UVW motion of the system does not match any known moving group, the small magnitude of the space velocity is consistent with youth. Near-IR spectroscopy shows HD 1160 C to be an M3.5 {+-} 0.5 star with an estimated mass of 0.22{sup +0.03}{sub -0.04} M{sub Sun }, while NIR photometry of HD 1160 B suggests a brown dwarf with a mass of 33{sup +12}{sub -9} M{sub Jup}. The very small mass ratio (0.014) between the A and B components of the system is rare for A star binaries, and would represent a planetary-mass companion were HD 1160 A to be slightly less massive than the Sun.

  6. POLARIMETRY WITH THE GEMINI PLANET IMAGER: METHODS, PERFORMANCE AT FIRST LIGHT, AND THE CIRCUMSTELLAR RING AROUND HR 4796A

    SciTech Connect

    Perrin, Marshall D.; Duchene, Gaspard; Graham, James R.; Kalas, Paul G.; Millar-Blanchaer, Max; Fitzgerald, Michael P.; Chilcote, Jeffrey; Wiktorowicz, Sloane J.; Dillon, Daren; Gavel, Donald; Macintosh, Bruce; Bauman, Brian; Cardwell, Andrew; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; De Rosa, Robert J.; Doyon, René; Dunn, Jennifer; Erikson, Darren; and others

    2015-02-01

    We present the first results from the polarimetry mode of the Gemini Planet Imager (GPI), which uses a new integral field polarimetry architecture to provide high contrast linear polarimetry with minimal systematic biases between the orthogonal polarizations. We describe the design, data reduction methods, and performance of polarimetry with GPI. Point-spread function (PSF) subtraction via differential polarimetry suppresses unpolarized starlight by a factor of over 100, and provides sensitivity to circumstellar dust reaching the photon noise limit for these observations. In the case of the circumstellar disk around HR 4796A, GPI's advanced adaptive optics system reveals the disk clearly even prior to PSF subtraction. In polarized light, the disk is seen all the way in to its semi-minor axis for the first time. The disk exhibits surprisingly strong asymmetry in polarized intensity, with the west side ≳ 9 times brighter than the east side despite the fact that the east side is slightly brighter in total intensity. Based on a synthesis of the total and polarized intensities, we now believe that the west side is closer to us, contrary to most prior interpretations. Forward scattering by relatively large silicate dust particles leads to the strong polarized intensity on the west side, and the ring must be slightly optically thick in order to explain the lower brightness in total intensity there. These findings suggest that the ring is geometrically narrow and dynamically cold, perhaps shepherded by larger bodies in the same manner as Saturn's F ring.

  7. First scattered-light image of the debris disk around HD 131835 with the Gemini Planet Imager

    DOE PAGES

    Hung, Li -Wei; Duchêne, Gaspard; Arriaga, Pauline; Fitzgerald, Michael P.; Maire, Jérôme; Marois, Christian; Millar-Blanchaer, Maxwell A.; Bruzzone, Sebastian; Rajan, Abhijith; Pueyo, Laurent; et al

    2015-12-09

    Here, we present the first scattered-light image of the debris disk around HD 131835 in the H band using the Gemini Planet Imager. HD 131835 is a ~15 Myr old A2IV star at a distance of ~120 pc in the Sco-Cen OB association. We detect the disk only in polarized light and place an upper limit on the peak total intensity. No point sources resembling exoplanets were identified. Compared to its mid-infrared thermal emission, in scattered light the disk shows similar orientation but different morphology. The scattered-light disk extends from ~75 to ~210 AU in the disk plane with roughlymore » flat surface density. Our Monte Carlo radiative transfer model can describe the observations with a model disk composed of a mixture of silicates and amorphous carbon. In addition to the obvious brightness asymmetry due to stronger forward scattering, we discover a weak brightness asymmetry along the major axis, with the northeast side being 1.3 times brighter than the southwest side at a 3σ level.« less

  8. First scattered-light image of the debris disk around HD 131835 with the Gemini Planet Imager

    SciTech Connect

    Hung, Li -Wei; Duchêne, Gaspard; Arriaga, Pauline; Fitzgerald, Michael P.; Maire, Jérôme; Marois, Christian; Millar-Blanchaer, Maxwell A.; Bruzzone, Sebastian; Rajan, Abhijith; Pueyo, Laurent; Kalas, Paul G.; De Rosa, Robert J.; Graham, James R.; Konopacky, Quinn; Wolff, Schuyler G.; Ammons, S. Mark; Chen, Christine H.; Chilcote, Jeffrey K.; Draper, Zachary H.; Esposito, Thomas M.; Gerard, Benjamin; Goodsell, Stephen; Greenbaum, Alexandra; Hibon, Pascale; Hinkley, Sasha; Macintosh, Bruce; Marchis, Franck; Metchev, Stanimir; Nielsen, Eric L.; Oppenheimer, Rebecca; Patience, Jennifer L.; Perrin, Marshall D.; Rantakyrö, Fredrik T.; Sivaramakrishnan, Anand; Wang, Jason J.; Ward-Duong, Kimberly; Wiktorowicz, Sloane J.

    2015-12-09

    Here, we present the first scattered-light image of the debris disk around HD 131835 in the H band using the Gemini Planet Imager. HD 131835 is a ~15 Myr old A2IV star at a distance of ~120 pc in the Sco-Cen OB association. We detect the disk only in polarized light and place an upper limit on the peak total intensity. No point sources resembling exoplanets were identified. Compared to its mid-infrared thermal emission, in scattered light the disk shows similar orientation but different morphology. The scattered-light disk extends from ~75 to ~210 AU in the disk plane with roughly flat surface density. Our Monte Carlo radiative transfer model can describe the observations with a model disk composed of a mixture of silicates and amorphous carbon. In addition to the obvious brightness asymmetry due to stronger forward scattering, we discover a weak brightness asymmetry along the major axis, with the northeast side being 1.3 times brighter than the southwest side at a 3σ level.

  9. Astrometric confirmation and preliminary orbital parameters of the young exoplanet 51 Eridani b with the Gemini Planet Imager

    SciTech Connect

    De Rosa, Robert J.; Nielsen, Eric L.; Blunt, Sarah C.; Graham, James R.; Konopacky, Quinn M.; Marois, Christian; Pueyo, Laurent; Rameau, Julien; Ryan, Dominic M.; Wang, Jason J.; Bailey, Vanessa; Chontos, Ashley; Fabrycky, Daniel C.; Follette, Katherine B.; Macintosh, Bruce; Marchis, Franck; Ammons, S. Mark; Arriaga, Pauline; Chilcote, Jeffrey K.; Cotten, Tara H.; Doyon, René; Duchêne, Gaspard; Fitzgerald, Michael P.; Gerard, Benjamin; Goodsell, Stephen J.; Greenbaum, Alexandra Z.; Hibon, Pascale; Ingraham, Patrick; Johnson-Groh, Mara; Kalas, Paul G.; Lafrenière, David; Maire, Jerome; Metchev, Stanimir; Millar-Blanchaer, Maxwell A.; Morzinski, Katie M.; Oppenheimer, Rebecca; Patel, Rahul I.; Patience, Jennifer L.; Perrin, Marshall D.; Rajan, Abhijith; Rantakyrö, Fredrik T.; Ruffio, Jean-Baptiste; Schneider, Adam C.; Sivaramakrishnan, Anand; Song, Inseok; Tran, Debby; Vasisht, Gautam; Ward-Duong, Kimberly; Wolff, Schuyler G.

    2015-11-13

    We present new Gemini Planet Imager observations of the young exoplanet 51 Eridani b that provide further evidence that the companion is physically associated with 51 Eridani. Combining this new astrometric measurement with those reported in the literature, we significantly reduce the posterior probability that 51 Eridani b is an unbound foreground or background T-dwarf in a chance alignment with 51 Eridani to 2 × 10–7, an order of magnitude lower than previously reported. If 51 Eridani b is indeed a bound object, then we have detected orbital motion of the planet between the discovery epoch and the latest epoch. By implementing a computationally efficient Monte Carlo technique, preliminary constraints are placed on the orbital parameters of the system. The current set of astrometric measurements suggest an orbital semimajor axis of ${14}_{-3}^{+7}$ AU, corresponding to a period of ${41}_{-12}^{+35}$ years (assuming a mass of 1.75 M⊙ for the central star), and an inclination of ${138}_{-13}^{+15}$ deg. The remaining orbital elements are only marginally constrained by the current measurements. As a result, these preliminary values suggest an orbit that does not share the same inclination as the orbit of the distant M-dwarf binary, GJ 3305, which is a wide physically bound companion to 51 Eridani.

  10. Astrometric confirmation and preliminary orbital parameters of the young exoplanet 51 Eridani b with the Gemini Planet Imager

    DOE PAGES

    De Rosa, Robert J.; Nielsen, Eric L.; Blunt, Sarah C.; Graham, James R.; Konopacky, Quinn M.; Marois, Christian; Pueyo, Laurent; Rameau, Julien; Ryan, Dominic M.; Wang, Jason J.; et al

    2015-11-13

    We present new Gemini Planet Imager observations of the young exoplanet 51 Eridani b that provide further evidence that the companion is physically associated with 51 Eridani. Combining this new astrometric measurement with those reported in the literature, we significantly reduce the posterior probability that 51 Eridani b is an unbound foreground or background T-dwarf in a chance alignment with 51 Eridani to 2 × 10–7, an order of magnitude lower than previously reported. If 51 Eridani b is indeed a bound object, then we have detected orbital motion of the planet between the discovery epoch and the latest epoch. By implementing a computationally efficient Monte Carlo technique, preliminary constraints are placed on the orbital parameters of the system. The current set of astrometric measurements suggest an orbital semimajor axis ofmore » $${14}_{-3}^{+7}$$ AU, corresponding to a period of $${41}_{-12}^{+35}$$ years (assuming a mass of 1.75 M⊙ for the central star), and an inclination of $${138}_{-13}^{+15}$$ deg. The remaining orbital elements are only marginally constrained by the current measurements. As a result, these preliminary values suggest an orbit that does not share the same inclination as the orbit of the distant M-dwarf binary, GJ 3305, which is a wide physically bound companion to 51 Eridani.« less

  11. Polarimetry with the Gemini Planet Imager. Methods, performance at first light, and the circumstellar ring around HR 4796A

    SciTech Connect

    Perrin, Marshall D.; Duchene, Gaspard; Millar-Blanchaer, Max; Fitzgerald, Michael P.; Graham, James R.; Wiktorowicz, Sloane J.; Kalas, Paul G.; Macintosh, Bruce; Bauman, Brian; Cardwell, Andrew; Chilcote, Jeffrey; De Rosa, Robert J.; Dillon, Daren; Doyon, René; Dunn, Jennifer; Erikson, Darren; Gavel, Donald; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Kerley, Daniel; Konapacky, Quinn; Larkin, James E.; Maire, Jérôme; Marchis, Franck; Marois, Christian; Mittal, Tushar; Morzinski, Katie M.; Oppenheimer, B. R.; Palmer, David W.; Patience, Jennifer; Poyneer, Lisa; Pueyo, Laurent; Rantakyrö, Fredrik T.; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Soummer, Rémi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wang, Jason J.; Wolff, Schuyler G.

    2015-01-28

    We report he first results from the polarimetry mode of the Gemini Planet Imager (GPI), which uses a new integral field polarimetry architecture to provide high contrast linear polarimetry with minimal systematic biases between the orthogonal polarizations. We describe the design, data reduction methods, and performance of polarimetry with GPI. Point-spread function (PSF) subtraction via differential polarimetry suppresses unpolarized starlight by a factor of over 100, and provides sensitivity to circumstellar dust reaching the photon noise limit for these observations. In the case of the circumstellar disk around HR 4796A, GPI’s advanced adaptive optics system reveals the disk clearly even prior to PSF subtraction. In polarized light, the disk is seen all the way in to its semi-minor axis for the first time. The disk exhibits surprisingly strong asymmetry in polarized intensity, with the west side ≳9 times brighter than the east side despite the fact that the east side is slightly brighter in total intensity. Based on a synthesis of the total and polarized intensities, we now believe that the west side is closer to us, contrary to most prior interpretations. Forward scattering by relatively large silicate dust particles leads to the strong polarized intensity on the west side, and the ring must be slightly optically thick in order to explain the lower brightness in total intensity there. In conclusion, these findings suggest that the ring is geometrically narrow and dynamically cold, perhaps shepherded by larger bodies in the same manner as Saturn’s F ring.

  12. Polarimetry with the Gemini Planet Imager: methods, performance at first light, and the circumstellar ring around HR 4796A

    SciTech Connect

    Perrin, Marshall D.; Duchene, Gaspard; Millar-Blanchaer, Max; Fitzgerald, Michael P.; Graham, James R.; Wiktorowicz, Sloane J.; Kalas, Paul G.; Macintosh, Bruce; Bauman, Brian; Cardwell, Andrew; Chilcote, Jeffrey; De Rosa, Robert J.; Dillon, Daren; Doyon, René; Dunn, Jennifer; Erikson, Darren; Gavel, Donald; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Kerley, Daniel; Konapacky, Quinn; Larkin, James E.; Maire, Jérôme; Marchis, Franck; Marois, Christian; Mittal, Tushar; Morzinski, Katie M.; Oppenheimer, B. R.; Palmer, David W.; Patience, Jennifer; Poyneer, Lisa; Pueyo, Laurent; Rantakyrö, Fredrik T.; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Soummer, Rémi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wang, Jason J.; Wolff, Schuyler G.

    2015-01-28

    We present the first results from the polarimetry mode of the Gemini Planet Imager (GPI), which uses a new integral field polarimetry architecture to provide high contrast linear polarimetry with minimal systematic biases between the orthogonal polarizations. We describe the design, data reduction methods, and performance of polarimetry with GPI. Point spread function subtraction via di erential polarimetry suppresses unpolarized starlight by a factor of over 100, and provides sensitivity to circumstellar dust reaching the photon noise limit for these observations. In the case of the circumstellar disk around HR 4796A, GPI's advanced adaptive optics system reveals the disk clearly even prior to PSF subtraction. In polarized light, the disk is seen all the way in to its semi-minor axis for the first time. The disk exhibits surprisingly strong asymmetry in polarized intensity, with the west side ≳ 9 times brighter than the east side despite the fact that the east side is slightly brighter in total intensity. Based on a synthesis of the total and polarized intensities, we now believe that the west side is closer to us, contrary to most prior interpretations. Forward scattering by relatively large silicate dust particles leads to the strong polarized intensity on the west side, and the ring must be slightly optically thick in order to explain the lower brightness in total intensity there. These findings suggest that the ring is geometrically narrow and dynamically cold, perhaps shepherded by larger bodies in the same manner as Saturn's F ring.

  13. A spectroscopic and molecular dynamic approach on the interaction between ionic liquid type gemini surfactant and human serum albumin.

    PubMed

    Maurya, Jitendra Kumar; Mir, Muzaffar Ul Hassan; Maurya, Neha; Dohare, Neeraj; Ali, Anwar; Patel, Rajan

    2016-10-01

    The interactions of imidazolium bashed ionic liquid-type cationic gemini surfactant ([C12-4-C12im]Br2) with HSA were studied by fluorescence, time-resolved fluorescence, UV-visible, circular dichroism, molecular docking and molecular dynamic simulation methods. The results showed that the [C12-4-C12im]Br2 quenched the fluorescence of HSA through dynamic quenching mechanism as confirmed by time-resolved spectroscopy. The Stern-Volmer quenching constant (Ksv) and relevant thermodynamic parameters such as enthalpy change (ΔH), Gibbs free energy change (ΔG) and entropy change (ΔS) for interaction system were calculated at different temperatures. The results revealed that hydrophobic forces played a major role in the interactions process. The results of synchronous fluorescence, UV-visible and CD spectra demonstrated that the binding of [C12-4-C12im]Br2 with HSA induces conformational changes in HSA. Inquisitively, the molecular dynamics study contribute towards understanding the effect of binding of [C12-4-C12im]Br2 on HSA to interpret the conformational change in HSA upon binding in aqueous solution. Moreover, the molecular modelling results show the possible binding sites in the interaction system.

  14. A Gemini/GMOS Study of Intermediate Luminosity Early-type Virgo Cluster Galaxies. I. Globular Cluster and Stellar Kinematics

    NASA Astrophysics Data System (ADS)

    Li, Biao; Peng, Eric W.; Zhang, Hong-xin; Blakeslee, John P.; Côté, Patrick; Ferrarese, Laura; Jordán, Andrés; Liu, Chengze; Mei, Simona; Puzia, Thomas H.; Takamiya, Marianne; Trancho, Gelys; West, Michael J.

    2015-06-01

    We present a kinematic analysis of the globular cluster (GC) systems and diffuse stellar light of four intermediate luminosity (sub-L*) early-type galaxies in the Virgo cluster based on Gemini Multi-Object Spectrographs (GMOS) data. Our galaxy sample is fainter (-23.8\\lt {{M}K}\\lt -22.7) than most previous studies, nearly doubling the number of galaxies in this magnitude range that now have GC kinematics. The data for the diffuse light extends to 4Re, and the data for the GCs reaches 8-12Re. We find that the kinematics in these outer regions are all different despite the fact that these four galaxies have similar photometric properties, and are uniformly classified as “fast rotators” from their stellar kinematics within 1Re. The GC systems exhibit a wide range of kinematic morphology. The rotation axis and amplitude can change between the inner and outer regions, including a case of counter-rotation. This difference shows the importance of wide-field kinematic studies, and shows that stellar and GC kinematics can change significantly as one moves beyond the inner regions of galaxies. Moreover, the kinematics of the GC systems can differ from that of the stars, suggesting that the formation of the two populations are also distinct.

  15. The Triaxial Ellipsoid Diameters and Rotational Pole of Asteroid (9) Metis from AO at Gemini and Keck

    NASA Astrophysics Data System (ADS)

    Drummond, Jack D.; Merline, W. J.; Conrad, A.; Dumas, C.; Tamblyn, P.; Christou, J.; Carry, B.; Chapman, C.

    2012-10-01

    From Adaptive Optics (AO) images of (9) Metis at 14 epochs over 2008 December 8 and 9 at Gemini North, triaxial ellipsoid diameters of 218x175x112 km are derived with fitting uncertainties of 3x3x47 km. However, by including just two more AO images from Keck-II in June and August of 2003 in a global fit, the fitting uncertainty of the small axis drops by more than a third because of the lower sub-Earth latitude afforded in 2003 (-28°) compared to 2008 (+47°), and the triaxial ellipsoid diameters become 218x175x129 km with fitting uncertainties of 3x3x14 km. We have estimated the systematic uncertainty of our method to be 4.1, 2.7, and 3.8%, respectively, for the three diameters. These values were recently derived (Drummond et al., in prep) from a comparison of KOALA (Carry et al, Planetary and Space Science 66, 200-212) and our triaxial ellipsoid analysis of four asteroids. Quadratically adding this systematic error with the fitting error, the total uncertainty for Metis becomes 9x5x15 km. Concurrently, we find an EQJ2000 rotational pole at [RA; Dec]=[185° +19°] or in ecliptic coordinates, [λ ; β ]=[176° +20°] (ECJ2000).

  16. Polarimetry with the Gemini Planet Imager: Methods, Performance at First Light, and the Circumstellar Ring around HR 4796A

    NASA Astrophysics Data System (ADS)

    Perrin, Marshall D.; Duchene, Gaspard; Millar-Blanchaer, Max; Fitzgerald, Michael P.; Graham, James R.; Wiktorowicz, Sloane J.; Kalas, Paul G.; Macintosh, Bruce; Bauman, Brian; Cardwell, Andrew; Chilcote, Jeffrey; De Rosa, Robert J.; Dillon, Daren; Doyon, René; Dunn, Jennifer; Erikson, Darren; Gavel, Donald; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Kerley, Daniel; Konapacky, Quinn; Larkin, James E.; Maire, Jérôme; Marchis, Franck; Marois, Christian; Mittal, Tushar; Morzinski, Katie M.; Oppenheimer, B. R.; Palmer, David W.; Patience, Jennifer; Poyneer, Lisa; Pueyo, Laurent; Rantakyrö, Fredrik T.; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Soummer, Rémi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wang, Jason J.; Wolff, Schuyler G.

    2015-02-01

    We present the first results from the polarimetry mode of the Gemini Planet Imager (GPI), which uses a new integral field polarimetry architecture to provide high contrast linear polarimetry with minimal systematic biases between the orthogonal polarizations. We describe the design, data reduction methods, and performance of polarimetry with GPI. Point-spread function (PSF) subtraction via differential polarimetry suppresses unpolarized starlight by a factor of over 100, and provides sensitivity to circumstellar dust reaching the photon noise limit for these observations. In the case of the circumstellar disk around HR 4796A, GPI's advanced adaptive optics system reveals the disk clearly even prior to PSF subtraction. In polarized light, the disk is seen all the way in to its semi-minor axis for the first time. The disk exhibits surprisingly strong asymmetry in polarized intensity, with the west side >~ 9 times brighter than the east side despite the fact that the east side is slightly brighter in total intensity. Based on a synthesis of the total and polarized intensities, we now believe that the west side is closer to us, contrary to most prior interpretations. Forward scattering by relatively large silicate dust particles leads to the strong polarized intensity on the west side, and the ring must be slightly optically thick in order to explain the lower brightness in total intensity there. These findings suggest that the ring is geometrically narrow and dynamically cold, perhaps shepherded by larger bodies in the same manner as Saturn's F ring.

  17. Searching for Binary Y Dwarfs with the Gemini Multi-conjugate Adaptive Optics System (GeMS)

    NASA Astrophysics Data System (ADS)

    Opitz, Daniela; Tinney, C. G.; Faherty, Jacqueline K.; Sweet, Sarah; Gelino, Christopher R.; Kirkpatrick, J. Davy

    2016-03-01

    The NASA Wide-field Infrared Survey Explorer (WISE) has discovered almost all the known members of the new class of Y-type brown dwarfs. Most of these Y dwarfs have been identified as isolated objects in the field. It is known that binaries with L- and T-type brown dwarf primaries are less prevalent than either M-dwarf or solar-type primaries, they tend to have smaller separations and are more frequently detected in near-equal mass configurations. The binary statistics for Y-type brown dwarfs, however, are sparse, and so it is unclear if the same trends that hold for L- and T-type brown dwarfs also hold for Y-type ones. In addition, the detection of binary companions to very cool Y dwarfs may well be the best means available for discovering even colder objects. We present results for binary properties of a sample of five WISE Y dwarfs with the Gemini Multi-Conjugate Adaptive Optics System. We find no evidence for binary companions in these data, which suggests these systems are not equal-luminosity (or equal-mass) binaries with separations larger than ˜0.5-1.9 AU. For equal-mass binaries at an age of 5 Gyr, we find that the binary binding energies ruled out by our observations (i.e., 1042 erg) are consistent with those observed in previous studies of hotter ultra-cool dwarfs.

  18. A uGNI-Based Asynchronous Message-driven Runtime System for Cray Supercomputers with Gemini Interconnect

    SciTech Connect

    Sun, Yanhua; Zheng, Gengbin; Olson, Ryan M; Jones, Terry R; Kale, Laxmikant V

    2012-01-01

    Gemini as the network for new Cray XE/XT systems features low latency, high bandwidth and strong scalability. Its hardware support for remote direct memory access enables efficient implementation of the global address space programming languages. Although the Generic Network Interface (GNI) is designed to support message-passing applications, it is still challenging to attain good performance for applications written in alternative programming models, such as the message-driven programming model. In our earlier work we showed that CHARM++, an object-oriented message-driven programming model, scales up to the full Jaguar Cray machine. In this paper, we describe a general and light-weight asynchronous Low-level RunTime System (LRTS) for CHARM+, and its implementation on the uGNI software stack for Cray XE systems. Several techniques are presented to exploit the uGNI capability by reducing memory copy and registration overhead, taking advantage of persistent communication, and improving intra-node communication. Our micro-benchmark results demonstrate that the uGNI-based runtime system outperforms the MPI-based implementation by up to 50% in terms of message latency. For communication intensive applications such as N-Queens, this implementation scales up to 15,360 cores of a Cray XE6 machine and is 70% faster than an MPI-based implementation. In molecular dynamics application NAMD, the performance is also considerably improved by as high as 18%.

  19. Peering into the Giant-planet-forming Region of the TW Hydrae Disk with the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Rapson, Valerie A.; Kastner, Joel H.; Millar-Blanchaer, Maxwell A.; Dong, Ruobing

    2015-12-01

    We present Gemini Planet Imager (GPI) adaptive optics near-infrared images of the giant-planet-forming regions of the protoplanetary disk orbiting the nearby (D = 54 pc), pre-main-sequence (classical T Tauri) star TW Hydrae. The GPI images, which were obtained in coronagraphic/polarimetric mode, exploit starlight scattered off small dust grains to elucidate the surface density structure of the TW Hya disk from ∼80 AU to within ∼10 AU of the star at ∼1.5 AU resolution. The GPI polarized intensity images unambiguously confirm the presence of a gap in the radial surface brightness distribution of the inner disk. The gap is centered near ∼23 AU, with a width of ∼5 AU and a depth of ∼50%. In the context of recent simulations of giant-planet formation in gaseous, dusty disks orbiting pre-main-sequence stars, these results indicate that at least one young planet with a mass ∼0.2 MJ could be present in the TW Hya disk at an orbital semimajor axis similar to that of Uranus. If this (proto)planet is actively accreting gas from the disk, it may be readily detectable by GPI or a similarly sensitive, high-resolution infrared imaging system.

  20. First Scattered-light Image of the Debris Disk around HD 131835 with the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Hung, Li-Wei; Duchêne, Gaspard; Arriaga, Pauline; Fitzgerald, Michael P.; Maire, Jérôme; Marois, Christian; Millar-Blanchaer, Maxwell A.; Bruzzone, Sebastian; Rajan, Abhijith; Pueyo, Laurent; Kalas, Paul G.; De Rosa, Robert J.; Graham, James R.; Konopacky, Quinn; Wolff, Schuyler G.; Ammons, S. Mark; Chen, Christine H.; Chilcote, Jeffrey K.; Draper, Zachary H.; Esposito, Thomas M.; Gerard, Benjamin; Goodsell, Stephen; Greenbaum, Alexandra; Hibon, Pascale; Hinkley, Sasha; Macintosh, Bruce; Marchis, Franck; Metchev, Stanimir; Nielsen, Eric L.; Oppenheimer, Rebecca; Patience, Jennifer L.; Perrin, Marshall D.; Rantakyrö, Fredrik T.; Sivaramakrishnan, Anand; Wang, Jason J.; Ward-Duong, Kimberly; Wiktorowicz, Sloane J.

    2015-12-01

    We present the first scattered-light image of the debris disk around HD 131835 in the H band using the Gemini Planet Imager. HD 131835 is a ∼15 Myr old A2IV star at a distance of ∼120 pc in the Sco-Cen OB association. We detect the disk only in polarized light and place an upper limit on the peak total intensity. No point sources resembling exoplanets were identified. Compared to its mid-infrared thermal emission, in scattered light the disk shows similar orientation but different morphology. The scattered-light disk extends from ∼75 to ∼210 AU in the disk plane with roughly flat surface density. Our Monte Carlo radiative transfer model can describe the observations with a model disk composed of a mixture of silicates and amorphous carbon. In addition to the obvious brightness asymmetry due to stronger forward scattering, we discover a weak brightness asymmetry along the major axis, with the northeast side being 1.3 times brighter than the southwest side at a 3σ level.

  1. Synthesis of Multibranched Gold Nanoechinus Using a Gemini Cationic Surfactant and Its Application for Surface Enhanced Raman Scattering.

    PubMed

    Vijayaraghavan, Priya; Liu, Cheng-Hong; Hwang, Kuo Chu

    2016-09-14

    High-yield multibranched Au nanoechinus possessing lengthy and dense branched nanorods on the surface were synthesized using a seed-mediated surfactant-directed approach in the presence of gemini cationic surfactant N,N,N'N'-tetramethyl-N,N'-ditetradecylethane-1,2-diaminium bromide (C14C2C14Br2), HAuCl4, AgNO3, and ascorbic acid. C14C2C14Br2 surfactant provides a versatile template in designing the unique morphology of Au nanoechinus with the assistance of AgNO3. UV-vis spectroscopic analysis proves that Au nanoechinus possess a unique intense broad localized surface plasmon resonance (LSPR) peak, which extends from 400 to 1700 nm in the NIR region making a highly potential platform for biomedical applications. Systematic time-dependent TEM, UV-vis-NIR, and XRD analysis were performed to monitor the morphological evolution of multibranched Au nanoechinus. It was found that the surface of branched nanorods of Au NE preferentially grew along (111) crystal planes. Furthermore, as-synthesized Au nanoechinus shows excellent SERS enhancement ability for dopamine inside HeLa cells. PMID:27556284

  2. South Polarscape

    NASA Technical Reports Server (NTRS)

    2006-01-01

    25 March 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a spectacular summertime view of a portion of the south polar residual cap. Large, semi-continuous mesas are separated by circular and other oddly-shaped depressions. These features are all formed in frozen carbon dioxide; the scarps which bound the mesas and pit walls retreat at a rate of about 3 meters (a little more than 3 yards) each martian southern summer.

    Location near: 87.7oS, 357.3oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  3. Cationic liposomes formulated with DMPC and a gemini surfactant traverse the cell membrane without causing a significant bio-damage.

    PubMed

    Stefanutti, E; Papacci, F; Sennato, S; Bombelli, C; Viola, I; Bonincontro, A; Bordi, F; Mancini, G; Gigli, G; Risuleo, G

    2014-10-01

    Cationic liposomes have been intensively studied both in basic and applied research because of their promising potential as non-viral molecular vehicles. This work was aimed to gain more information on the interactions between the plasmamembrane and liposomes formed by a natural phospholipid and a cationic surfactant of the gemini family. The present work was conducted with the synergistic use of diverse experimental approaches: electro-rotation measurements, atomic force microscopy, ζ-potential measurements, laser scanning confocal microscopy and biomolecular/cellular techniques. Electro-rotation measurements pointed out that the interaction of cationic liposomes with the cell membrane alters significantly its dielectric and geometric parameters. This alteration, being accompanied by significant changes of the membrane surface roughness as measured by atomic force microscopy, suggests that the interaction with the liposomes causes locally substantial modifications to the structure and morphology of the cell membrane. However, the results of electrophoretic mobility (ζ-potential) experiments show that upon the interaction the electric charge exposed on the cell surface does not vary significantly, pointing out that the simple adhesion on the cell surface of the cationic liposomes or their fusion with the membrane is to be ruled out. As a matter of fact, confocal microscopy images directly demonstrated the penetration of the liposomes inside the cell and their diffusion within the cytoplasm. Electro-rotation experiments performed in the presence of endocytosis inhibitors suggest that the internalization is mediated by, at least, one specific pathway. Noteworthy, the liposome uptake by the cell does not cause a significant biological damage.

  4. The Giant Gemini GMOS survey of zem > 4.4 quasars - I. Measuring the mean free path across cosmic time

    NASA Astrophysics Data System (ADS)

    Worseck, Gábor; Prochaska, J. Xavier; O'Meara, John M.; Becker, George D.; Ellison, Sara L.; Lopez, Sebastian; Meiksin, Avery; Ménard, Brice; Murphy, Michael T.; Fumagalli, Michele

    2014-12-01

    We have obtained spectra of 163 quasars at zem > 4.4 with the Gemini Multi Object Spectrometers, the largest publicly available sample of high-quality, low-resolution spectra at these redshifts. From this data set, we generated stacked quasar spectra in three redshift intervals at z ˜ 5 to model the average rest-frame Lyman continuum flux and to assess the mean free path λ _mfp^{912} of the intergalactic medium to H I-ionizing radiation. At mean redshifts zq = (4.56, 4.86, 5.16), we measure λ _mfp^{912}=(22.2 ± 2.3, 15.1 ± 1.8, 10.3 ± 1.6)h_{70}^{-1} proper Mpc with uncertainties dominated by sample variance. Combining our results with measurements from lower redshifts, the data are well modelled by a power law λ _mfp^{912}=A[(1+zright)/5]^η with A=(37 ± 2)h_{70}^{-1} Mpc and η = -5.4 ± 0.4 at 2.3 < z < 5.5. This rapid evolution requires a physical mechanism - beyond cosmological expansion - which reduces the effective Lyman limit opacity. We speculate that the majority of H I Lyman limit opacity manifests in gas outside galactic dark matter haloes, tracing large-scale structures (e.g. filaments) whose average density and neutral fraction decreases with cosmic time. Our measurements of the mean free path shortly after H I reionization serve as a valuable boundary condition for numerical models thereof. Our measured λ _mfp^{912}≈ 10 Mpc at z = 5.2 confirms that the intergalactic medium is highly ionized without evidence for a break that would indicate a recent end to H I reionization.

  5. Cationic liposomes formulated with DMPC and a gemini surfactant traverse the cell membrane without causing a significant bio-damage.

    PubMed

    Stefanutti, E; Papacci, F; Sennato, S; Bombelli, C; Viola, I; Bonincontro, A; Bordi, F; Mancini, G; Gigli, G; Risuleo, G

    2014-10-01

    Cationic liposomes have been intensively studied both in basic and applied research because of their promising potential as non-viral molecular vehicles. This work was aimed to gain more information on the interactions between the plasmamembrane and liposomes formed by a natural phospholipid and a cationic surfactant of the gemini family. The present work was conducted with the synergistic use of diverse experimental approaches: electro-rotation measurements, atomic force microscopy, ζ-potential measurements, laser scanning confocal microscopy and biomolecular/cellular techniques. Electro-rotation measurements pointed out that the interaction of cationic liposomes with the cell membrane alters significantly its dielectric and geometric parameters. This alteration, being accompanied by significant changes of the membrane surface roughness as measured by atomic force microscopy, suggests that the interaction with the liposomes causes locally substantial modifications to the structure and morphology of the cell membrane. However, the results of electrophoretic mobility (ζ-potential) experiments show that upon the interaction the electric charge exposed on the cell surface does not vary significantly, pointing out that the simple adhesion on the cell surface of the cationic liposomes or their fusion with the membrane is to be ruled out. As a matter of fact, confocal microscopy images directly demonstrated the penetration of the liposomes inside the cell and their diffusion within the cytoplasm. Electro-rotation experiments performed in the presence of endocytosis inhibitors suggest that the internalization is mediated by, at least, one specific pathway. Noteworthy, the liposome uptake by the cell does not cause a significant biological damage. PMID:25017801

  6. Resolving the HD 100546 Protoplanetary System with the Gemini Planet Imager: Evidence for Multiple Forming, Accreting Planets

    NASA Astrophysics Data System (ADS)

    Currie, Thayne; Cloutier, Ryan; Brittain, Sean; Grady, Carol; Burrows, Adam; Muto, Takayuki; Kenyon, Scott J.; Kuchner, Marc J.

    2015-12-01

    We report Gemini Planet Imager H-band high-contrast imaging/integral field spectroscopy and polarimetry of the HD 100546, a 10 Myr old early-type star recently confirmed to host a thermal infrared (IR) bright (super-)Jovian protoplanet at wide separation, HD 100546 b. We resolve the inner disk cavity in polarized light, recover the thermal IR-bright arm, and identify one additional spiral arm. We easily recover HD 100546 b and show that much of its emission plausibly originates from an unresolved point source. The point-source component of HD 100546 b has extremely red IR colors compared to field brown dwarfs, qualitatively similar to young cloudy super-Jovian planets; however, these colors may instead indicate that HD 100546 b is still accreting material from a circumplanetary disk. Additionally, we identify a second point-source-like peak at rproj ˜ 14 AU, located just interior to or at the inner disk wall consistent with being a <10-20 MJ candidate second protoplanet—“HD 100546 c”—and lying within a weakly polarized region of the disk but along an extension of the thermal IR-bright spiral arm. Alternatively, it is equally plausible that this feature is a weakly polarized but locally bright region of the inner disk wall. Astrometric monitoring of this feature over the next 2 years and emission line measurements could confirm its status as a protoplanet, rotating disk hot spot that is possibly a signpost of a protoplanet, or a stationary emission source from within the disk.

  7. Near-infrared detection and characterization of the exoplanet HD 95086 b with the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Galicher, R.; Rameau, J.; Bonnefoy, M.; Baudino, J.-L.; Currie, T.; Boccaletti, A.; Chauvin, G.; Lagrange, A.-M.; Marois, C.

    2014-05-01

    HD 95086 is an intermediate-mass debris-disk-bearing star. VLT/NaCo 3.8 μm observations revealed it hosts a 5 ± 2 MJup companion (HD 95086 b) at ≃56 AU. Follow-up observations at 1.66 and 2.18 μm yielded a null detection, suggesting extremely red colors for the planet and the need for deeper direct-imaging data. In this Letter, we report H-(1.7 μm) and K1-(2.05 μm) band detections of HD 95086 b from Gemini Planet Imager (GPI) commissioning observations taken by the GPI team. The planet position in both spectral channels is consistent with the NaCo measurements and we confirm it to be comoving. Our photometry yields colors of H - L' = 3.6 ± 1.0 mag and K1 - L' = 2.4 ± 0.7 mag, consistent with previously reported 5-σ upper limits in H and Ks. The photometry of HD 95086 b best matches that of 2M 1207 b and HR 8799 cde. Comparing its spectral energy distribution with the BT-SETTL and LESIA planet atmospheric models yields Teff ~ 600-1500 K and log g ~ 2.1-4.5. Hot-start evolutionary models yield M = 5 ± 2 MJup. Warm-start models reproduce the combined absolute fluxes of the object for M = 4-14 MJup for a wide range of plausible initial conditions (Sinit = 8-13 kB/baryon). The color-magnitude diagram location of HD 95086 b and its estimated Teff and log g suggest that the planet is a peculiar L - T transition object with an enhanced amount of photospheric dust. Based on public data taken at the GPI commissioning.

  8. Polymerizable gemini surfactants at solid/solution interfaces: adsorption and polymerization on melamine formaldehyde particles and capsule fabrication.

    PubMed

    Sakai, Kenichi; Izumi, Keiko; Sakai, Hideki; Abe, Masahiko

    2010-03-15

    Organic capsules have been fabricated via three steps, by using the polymerizable gemini surfactant (1,2-bis(dimethyl(11-methacryloyloxy)undecylammonio) hexane dibromide, PC11-6-11) as a single wall component. In the first fabrication step, the surfactant spontaneously adsorbs on acid-dissolvable melamine formaldehyde (MF) particles in aqueous media. The adsorption isotherm data reveal that the adsorbed amount of PC11-6-11 (per chain) is greater than that of the corresponding monomeric surfactant ((11-methacryloyloxy)undecyltrimethylammonium bromide, PC11), resulting from the greater intermolecular association of PC11-6-11 at the solid/solution interface. The closely packed adsorbed layer of PC11-6-11 provides an opportunity to give a polymer thin film, as a result of in situ photo-polymerization on MF particles (in the second fabrication step) and subsequent acid dissolution of the core MF particles (in the third fabrication step). The dynamic light scattering (DLS) measurements have shown that the apparent hydrodynamic diameter of PC11-6-11 capsules is reversibly changed in response to a change in ionic strength: the increased background electrolyte concentration results in deswelling of the capsules, and vice versa. It seems likely that this swelling/deswelling behavior is primarily driven by the electrostatic interaction between quaternary ammonium groups within the polymerized film. We have also studied the capture and release capabilities of glucose into/from the capsule core and found that (i) glucose is encapsulated into the capsule core at high electrolyte concentrations and (ii) the glucose molecules encapsulated into the core are gradually released when the outer electrolyte solution is replaced by pure water. We believe, therefore, that the PC11-6-11 capsules fabricated here are useful as stimulus-responsive smart vehicles.

  9. A Combined Very Large Telescope and Gemini Study of the Atmosphere of the Directly Imaged Planet, β Pictoris b

    NASA Astrophysics Data System (ADS)

    Currie, Thayne; Burrows, Adam; Madhusudhan, Nikku; Fukagawa, Misato; Girard, Julien H.; Dawson, Rebekah; Murray-Clay, Ruth; Kenyon, Scott; Kuchner, Marc; Matsumura, Soko; Jayawardhana, Ray; Chambers, John; Bromley, Ben

    2013-10-01

    We analyze new/archival VLT/NaCo and Gemini/NICI high-contrast imaging of the young, self-luminous planet β Pictoris b in seven near-to-mid IR photometric filters, using advanced image processing methods to achieve high signal-to-noise, high precision measurements. While β Pic b's near-IR colors mimic those of a standard, cloudy early-to-mid L dwarf, it is overluminous in the mid-infrared compared to the field L/T dwarf sequence. Few substellar/planet-mass objects—i.e., κ And b and 1RXJ 1609B—match β Pic b's JHKsL' photometry and its 3.1 μm and 5 μm photometry are particularly difficult to reproduce. Atmosphere models adopting cloud prescriptions and large (~60 μm) dust grains fail to reproduce the β Pic b spectrum. However, models incorporating thick clouds similar to those found for HR 8799 bcde, but also with small (a few microns) modal particle sizes, yield fits consistent with the data within the uncertainties. Assuming solar abundance models, thick clouds, and small dust particles (langarang = 4 μm), we derive atmosphere parameters of log (g) = 3.8 ± 0.2 and T eff = 1575-1650 K, an inferred mass of 7^{+4}_{-3} MJ , and a luminosity of log(L/L ⊙) ~-3.80 ± 0.02. The best-estimated planet radius, ≈1.65 ± 0.06 RJ , is near the upper end of allowable planet radii for hot-start models given the host star's age and likely reflects challenges constructing accurate atmospheric models. Alternatively, these radii are comfortably consistent with hot-start model predictions if β Pic b is younger than ≈7 Myr, consistent with a late formation well after its host star's birth ~12^{+8}_{-4} Myr ago.

  10. Polarimetry with the Gemini Planet Imager. Methods, performance at first light, and the circumstellar ring around HR 4796A

    DOE PAGES

    Perrin, Marshall D.; Duchene, Gaspard; Millar-Blanchaer, Max; Fitzgerald, Michael P.; Graham, James R.; Wiktorowicz, Sloane J.; Kalas, Paul G.; Macintosh, Bruce; Bauman, Brian; Cardwell, Andrew; et al

    2015-01-28

    We report he first results from the polarimetry mode of the Gemini Planet Imager (GPI), which uses a new integral field polarimetry architecture to provide high contrast linear polarimetry with minimal systematic biases between the orthogonal polarizations. We describe the design, data reduction methods, and performance of polarimetry with GPI. Point-spread function (PSF) subtraction via differential polarimetry suppresses unpolarized starlight by a factor of over 100, and provides sensitivity to circumstellar dust reaching the photon noise limit for these observations. In the case of the circumstellar disk around HR 4796A, GPI’s advanced adaptive optics system reveals the disk clearly evenmore » prior to PSF subtraction. In polarized light, the disk is seen all the way in to its semi-minor axis for the first time. The disk exhibits surprisingly strong asymmetry in polarized intensity, with the west side ≳9 times brighter than the east side despite the fact that the east side is slightly brighter in total intensity. Based on a synthesis of the total and polarized intensities, we now believe that the west side is closer to us, contrary to most prior interpretations. Forward scattering by relatively large silicate dust particles leads to the strong polarized intensity on the west side, and the ring must be slightly optically thick in order to explain the lower brightness in total intensity there. In conclusion, these findings suggest that the ring is geometrically narrow and dynamically cold, perhaps shepherded by larger bodies in the same manner as Saturn’s F ring.« less

  11. RESOLVING THE HD 100546 PROTOPLANETARY SYSTEM WITH THE GEMINI PLANET IMAGER: EVIDENCE FOR MULTIPLE FORMING, ACCRETING PLANETS

    SciTech Connect

    Currie, Thayne; Cloutier, Ryan; Brittain, Sean; Grady, Carol; Kuchner, Marc J.; Burrows, Adam; Muto, Takayuki; Kenyon, Scott J.

    2015-12-01

    We report Gemini Planet Imager H-band high-contrast imaging/integral field spectroscopy and polarimetry of the HD 100546, a 10 Myr old early-type star recently confirmed to host a thermal infrared (IR) bright (super-)Jovian protoplanet at wide separation, HD 100546 b. We resolve the inner disk cavity in polarized light, recover the thermal IR-bright arm, and identify one additional spiral arm. We easily recover HD 100546 b and show that much of its emission plausibly originates from an unresolved point source. The point-source component of HD 100546 b has extremely red IR colors compared to field brown dwarfs, qualitatively similar to young cloudy super-Jovian planets; however, these colors may instead indicate that HD 100546 b is still accreting material from a circumplanetary disk. Additionally, we identify a second point-source-like peak at r{sub proj} ∼ 14 AU, located just interior to or at the inner disk wall consistent with being a <10–20 M{sub J} candidate second protoplanet—“HD 100546 c”—and lying within a weakly polarized region of the disk but along an extension of the thermal IR-bright spiral arm. Alternatively, it is equally plausible that this feature is a weakly polarized but locally bright region of the inner disk wall. Astrometric monitoring of this feature over the next 2 years and emission line measurements could confirm its status as a protoplanet, rotating disk hot spot that is possibly a signpost of a protoplanet, or a stationary emission source from within the disk.

  12. A Combined Very Large Telescope and Gemini Study of the Atmosphere of the Directly Imaged Planet, Beta Pictoris b

    NASA Technical Reports Server (NTRS)

    Currie, Thayne; Burrows, Adam; Madhusudhan, Nikku; Fukagawa, Misato; Girard, Julien H.; Dawson, Rebekah; Murray-Clay, Ruth; Kenyon, Scott; Kuchner, Marc J.; Matsumura, Soko; Jayawardhana, Ray; Chambers, John; Bromley, Ben

    2013-01-01

    We analyze new/archival VLT/NaCo and Gemini/NICI high-contrast imaging of the young, self-luminous planet Beta Pictoris b in seven near-to-mid IR photometric filters, using advanced image processing methods to achieve high signal-to-noise, high precision measurements. While Beta Pic b's near-IR colors mimic those of a standard, cloudy early-to-mid L dwarf, it is overluminous in the mid-infrared compared to the field L/T dwarf sequence. Few substellar/planet-mass objects-i.e., ? And b and 1RXJ 1609B-match Beta Pic b's JHKsL photometry and its 3.1 micron and 5 micron photometry are particularly difficult to reproduce. Atmosphere models adopting cloud prescriptions and large (approx. 60 micron)dust grains fail to reproduce the Beta Pic b spectrum. However, models incorporating thick clouds similar to those found forHR8799 bcde, but also with small (a fewmicrons) modal particle sizes, yield fits consistent with the data within the uncertainties. Assuming solar abundance models, thick clouds, and small dust particles (a = 4 micron), we derive atmosphere parameters of log(g) = 3.8 +/- 0.2 and Teff = 1575-1650 K, an inferred mass of 7+4 -3 MJ, and a luminosity of log(L/L) approx. -3.80 +/- 0.02. The best-estimated planet radius, is approx. equal to 1.65 +/- 0.06 RJ, is near the upper end of allowable planet radii for hot-start models given the host star's age and likely reflects challenges constructing accurate atmospheric models. Alternatively, these radii are comfortably consistent with hot-start model predictions if Beta Pic b is younger than is approx. equal to 7 Myr, consistent with a late formation well after its host star's birth approx. 12+8 -4 Myr ago.

  13. How the Type of Cosurfactant Impacts Strongly on the Size and Interfacial Composition in Gemini 12-2-12 RMs Explored by DLS, SLS, and FTIR Techniques.

    PubMed

    Cuenca, Victor E; Falcone, R Darío; Silber, Juana J; Correa, N Mariano

    2016-01-28

    The limited amount of information about reverse micelles (RMs) made with gemini surfactants, the effect of the n-alcohols in their interface, and the water-entrapped structure in the polar core motivated us to perform this work. Thus, in the present contribution, we use dynamic light scattering (DLS), static light scattering (SLS), and FT-IR techniques to obtain information on RMs structure created, with the gemini dimethylene-1,2-bis(dodecyldimethylammonium) bromide (G12-2-12) surfactant and compare the results with its monomer: dodecyltrimethylammonium bromide (DTAB). In this way, the size of the aggregates formed in different nonpolar organic solvents, the effect of the chain length of n-alcohols used as cosurfactants, and the water-entrapped structure were explored. The data show that the structure of the cosurfactant needed to stabilize the RMs plays a fundamental role, affecting the size and behavior of the aggregates. In contrast to what happens with the RMs formed with the monomer DTAB, water entrapped inside G12-2-12 RMs displays different interaction with the interface depending on the hydrocarbon chain length of the n-alcohol used as cosurfactant. Thus, n-pentanol and n-octanol molecules are located in different regions in the RMs interfaces formed with the gemini surfactant. n-Octanol locates at the RMs interface among the surfactant hydrocarbon tails increasing the water-surfactant polar headgroup interaction. On the other hand, n-pentanol locates at the RMs interface near the polar core, limiting the interaction of water with the micellar inner interface and favoring the water-water interaction in the polar core.

  14. Polarized Light Imaging of the HD 142527 Transition Disk with the Gemini Planet Imager: Dust around the Close-in Companion

    NASA Astrophysics Data System (ADS)

    Rodigas, Timothy J.; Follette, Katherine B.; Weinberger, Alycia; Close, Laird; Hines, Dean C.

    2014-08-01

    When giant planets form, they grow by accreting gas and dust. HD 142527 is a young star that offers a scaled-up view of this process. It has a broad, asymmetric ring of gas and dust beyond ~100 AU and a wide inner gap. Within the gap, a low-mass stellar companion orbits the primary star at just ~12 AU, and both the primary and secondary are accreting gas. In an attempt to directly detect the dusty counterpart to this accreted gas, we have observed HD 142527 with the Gemini Planet Imager in polarized light at Y band (0.95-1.14 μm). We clearly detect the companion in total intensity and show that its position and photometry are generally consistent with the expected values. We also detect a point source in polarized light that may be spatially separated by ~ a few AU from the location of the companion in total intensity. This suggests that dust is likely falling onto or orbiting the companion. Given the possible contribution of scattered light from this dust to previously reported photometry of the companion, the current mass limits should be viewed as upper limits only. If the dust near the companion is eventually confirmed to be spatially separated, this system would resemble a scaled-up version of the young planetary system inside the gap of the transition disk around LkCa 15. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministrio da Cincia, Tecnologia e Inovao (Brazil), and Ministerio de Ciencia, Tecnologa e Innovacin Productiva (Argentina).

  15. The Gemini NICI Planet-finding Campaign: Discovery of a Close Substellar Companion to the Young Debris Disk Star PZ Tel

    NASA Astrophysics Data System (ADS)

    Biller, Beth A.; Liu, Michael C.; Wahhaj, Zahed; Nielsen, Eric L.; Close, Laird M.; Dupuy, Trent J.; Hayward, Thomas L.; Burrows, Adam; Chun, Mark; Ftaclas, Christ; Clarke, Fraser; Hartung, Markus; Males, Jared; Reid, I. Neill; Shkolnik, Evgenya L.; Skemer, Andrew; Tecza, Matthias; Thatte, Niranjan; Alencar, Silvia H. P.; Artymowicz, Pawel; Boss, Alan; de Gouveia Dal Pino, Elisabete; Gregorio-Hetem, Jane; Ida, Shigeru; Kuchner, Marc J.; Lin, Douglas; Toomey, Douglas

    2010-09-01

    We report the discovery of a tight substellar companion to the young solar analog PZ Tel, a member of the β Pic moving group observed with high-contrast adaptive optics imaging as part of the Gemini Near-Infrared Coronagraphic Imager Planet-Finding Campaign. The companion was detected at a projected separation of 16.4 ± 1.0 AU (0farcs33 ± 0farcs01) in 2009 April. Second-epoch observations in 2010 May demonstrate that the companion is physically associated and shows significant orbital motion. Monte Carlo modeling constrains the orbit of PZ Tel B to eccentricities >0.6. The near-IR colors of PZ Tel B indicate a spectral type of M7 ± 2 and thus this object will be a new benchmark companion for studies of ultracool, low-gravity photospheres. Adopting an age of 12+8 -4 Myr for the system, we estimate a mass of 36 ± 6 M Jup based on the Lyon/DUSTY evolutionary models. PZ Tel B is one of the few young substellar companions directly imaged at orbital separations similar to those of giant planets in our own solar system. Additionally, the primary star PZ Tel A shows a 70 μm emission excess, evidence for a significant quantity of circumstellar dust that has not been disrupted by the orbital motion of the companion. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  16. Adaptive optics point spread function reconstruction: lessons learned from on-sky experiment on Altair/Gemini and pathway for future systems

    NASA Astrophysics Data System (ADS)

    Jolissaint, Laurent; Christou, Julian; Wizinowich, Peter; Tolstoy, Eline

    2010-07-01

    We present the results of an on-sky point spread function reconstruction (PSF-R) experiment for the Gemini North telescope adaptive optics system, Altair, in the simplest mode, bright on-axis natural guise star. We demonstrate that our PSF-R method does work for system performance diagnostic but suffers from hidden telescope and system aberrations that are not accounted for in the model, making the reconstruction unsuccessful for Altair, for now. We discuss the probable origin of the discrepancy. In the last section, we propose alternative PSF-R methods for future multiple natural and laser guide stars systems.

  17. [South] Yemen.

    PubMed

    1989-12-01

    Yemen has an area of 112,000 square miles, the terrain is mountainous in the interior, and has a flat and sandy coast. The climate is extremely hot with little rainfall. 2.2 million is the population level with an annual growth rate of 2.6%. The ethnic background is Arab, the religion is Islam and the language is Arabic. 50 years is the average life expectancy and the infant mortality rate is 142/1000. The labor force is 42% agriculture, fisheries, industry and commerce 31%, and services 27%. A republic formed in 1967, the government has a constitution approved in 1978. They have 1 party, the Yemeni Socialist Party with a executive presidium, a supreme people's council and a federal high court. Natural resources include oil and fish, and agricultural products are cotton, hides, skins, and coffee. In 1962 the Federation of South Arabia was formed and a treaty was signed in 1959 for independence by 1968. There was much turmoil from 1967 until 1986 when Haydar Bakr Al-Attus gained power, and there are still strong internal rivalries. The economy has been concentrated in the city of Aden, and with the loss of tourist trade in 1967, and closing of the British base, it has declined by more than 20% by 1968. Attempts are being made to build roads, fisheries, villages, a power plant, and agriculture and irrigation projects.

  18. Chemical compatibility of (La{sub 0.6}Ca{sub 0.4}){sub x}Fe{sub 0.8}M{sub 0.2}O{sub 3} with yttria-stabilized zirconia

    SciTech Connect

    Kindermann, L.; Das, D.; Nickel, H.; Hilpert, K.; Appel, C.C.; Poulson, F.W.

    1997-02-01

    LaFeO{sub 3}-based perovskites are of interest as cathode material for the development of advanced solid oxide fuel cells operating at temperatures significantly lower than 900 C. The compatibility of the selected materials is necessary to guarantee long-term operation of a solid oxide fuel cell. Systematic investigations on the reactivity between the solid electrolyte yttria-stabilized zirconia (ZrO{sub 2} + 8 mole percent Y{sub 2}O{sub 3}) and the perovskites (La{sub 0.6}Ca{sub 0.4}){sub x}Fe{sub 0.8}M{sub 0.2}O{sub 3} (x = 1, 0.9; M = Cr, Mn, Co, Ni) were carried out. The results obtained are discussed.

  19. Crystal structure of Na 2MMgP 2O 8 ( M: Ba, Sr, Ca) orthophosphates and their luminescence properties activated by Eu 2+; analogous structural behaviors of glaserite-type phosphates and silicates

    NASA Astrophysics Data System (ADS)

    Yonesaki, Yoshinori; Matsuda, Chihiro

    2011-12-01

    Rietveld refinements of X-ray powder diffraction data and vibrational spectroscopy have confirmed the crystal structure of Na 2MMgP 2O 8 ( M: Ba, Sr, Ca) prepared by a standard solid state reaction. They have glaserite-type layered structure. Na 2MMgP 2O 8 has a trigonal P3¯ form for M=Ba, and monoclinic P2 1/ c forms for M=Sr and Ca. The observed structural transition is analogous to the corresponding layered orthosilicate M3MgSi 2O 8. Eu 2+-doped Na 2MMgP 2O 8 exhibits an intense blue to violet emission under ultraviolet excitation, based on 5 d-4 f electron transition of Eu 2+ ions. The emission character is very sensitive to the structural transition induced by M2+ and the subsequent site symmetry changes.

  20. Nanostructured Gd 0.8Sr 0.2Fe 0.8M 0.2O 3 (M=Cr, Ga) materials for solid oxide fuel cell cathodes

    NASA Astrophysics Data System (ADS)

    Ruiz de Larramendi, I.; Pinedo, R.; Ortiz-Vitoriano, N.; Ruiz de Larramendi, J. I.; Arriortua, M. I.; Rojo, T.

    Polycrystalline samples of Gd0.8Sr0.2Fe0.8M0.2O3 (M=Cr, Ga) are prepared by combustion route and pore wetting technique in order to compare the influence of the morphology in the performance of two cathodes for Solid Oxide Fuel Cells. When polycarbonate membranes are used as templates nanowire arrays with a diameter of 50-70 nm are obtained. Comparing the results obtained by Electrochemical Impedance Spectroscopy (EIS) measurements, it is clearly observed that the cathodic resistance considerably decreases when optimized synthesis parameters are used, obtaining a better performance for the Gd0.8Sr0.2Fe0.8Ga0.2O3 nanowires with an area specific resistance (ASR) value at 850 ∘C of 0.195 Ω cm2.

  1. A Novel Surface Structure Consisting of Contact-active Antibacterial Upper-layer and Antifouling Sub-layer Derived from Gemini Quaternary Ammonium Salt Polyurethanes

    PubMed Central

    He, Wei; Zhang, Yi; Li, Jiehua; Gao, Yunlong; Luo, Feng; Tan, Hong; Wang, Kunjie; Fu, Qiang

    2016-01-01

    Contact-active antibacterial surfaces play a vital role in preventing bacterial contamination of artificial surfaces. In the past, numerous researches have been focused on antibacterial surfaces comprising of antifouling upper-layer and antibacterial sub-layer. In this work, we demonstrate a reversed surface structure which integrate antibacterial upper-layer and antifouling sub-layer. These surfaces are prepared by simply casting gemini quaternary ammonium salt waterborne polyurethanes (GWPU) and their blends. Due to the high interfacial energy of gemini quaternary ammonium salt (GQAS), chain segments containing GQAS can accumulate at polymer/air interface to form an antibacterial upper-layer spontaneously during the film formation. Meanwhile, the soft segments composed of polyethylene glycol (PEG) formed the antifouling sub-layer. Our findings indicate that the combination of antibacterial upper-layer and antifouling sub-layer endow these surfaces strong, long-lasting antifouling and contact-active antibacterial properties, with a more than 99.99% killing efficiency against both gram-positive and gram-negative bacteria attached to them. PMID:27561546

  2. A 1H NMR Study of Host/Guest Supramolecular Complexes of a Curcumin Analogue with β-Cyclodextrin and a β-Cyclodextrin-Conjugated Gemini Surfactant.

    PubMed

    Poorghorban, Masoomeh; Karoyo, Abdalla H; Grochulski, Pawel; Verrall, Ronald E; Wilson, Lee D; Badea, Ildiko

    2015-08-01

    Host systems based on β-cyclodextrin (βCD) were employed as pharmaceutical carriers to encapsulate a poorly soluble drug, curcumin analogue (NC 2067), in order to increase its water solubility. βCD was chemically conjugated with an amphiphilic gemini surfactant with the ability to self-assemble and to form nanoscale supramolecular structures. The conjugated molecule, βCDgemini surfactant (βCDg), was shown to be a promising drug delivery agent. In this report, its physicochemical properties were assessed in aqueous solution using 1D and 2D 1H NMR spectroscopy. The results showed that the apolar hydrocarbon domain of the gemini surfactant was self-included within the βCD internal cavity. The host/guest complexes composed of native βCD or βCDg with NC 2067 were examined using 1D/2D ROESY NMR methods. The stoichiometry of βCD/NC 2067 complex was estimated using Job's method via 1H NMR spectroscopy. The binding geometry of NC 2067 within βCD was proposed using molecular docking and further supported by 1D and 2D ROESY NMR results. Addition of NC 2067 to βCDg revealed minimal changes to the overall structure of the βCDg system, in agreement with the formation of a βCDg/NC 2067 ternary complex. PMID:26083126

  3. A Novel Surface Structure Consisting of Contact-active Antibacterial Upper-layer and Antifouling Sub-layer Derived from Gemini Quaternary Ammonium Salt Polyurethanes

    NASA Astrophysics Data System (ADS)

    He, Wei; Zhang, Yi; Li, Jiehua; Gao, Yunlong; Luo, Feng; Tan, Hong; Wang, Kunjie; Fu, Qiang

    2016-08-01

    Contact-active antibacterial surfaces play a vital role in preventing bacterial contamination of artificial surfaces. In the past, numerous researches have been focused on antibacterial surfaces comprising of antifouling upper-layer and antibacterial sub-layer. In this work, we demonstrate a reversed surface structure which integrate antibacterial upper-layer and antifouling sub-layer. These surfaces are prepared by simply casting gemini quaternary ammonium salt waterborne polyurethanes (GWPU) and their blends. Due to the high interfacial energy of gemini quaternary ammonium salt (GQAS), chain segments containing GQAS can accumulate at polymer/air interface to form an antibacterial upper-layer spontaneously during the film formation. Meanwhile, the soft segments composed of polyethylene glycol (PEG) formed the antifouling sub-layer. Our findings indicate that the combination of antibacterial upper-layer and antifouling sub-layer endow these surfaces strong, long-lasting antifouling and contact-active antibacterial properties, with a more than 99.99% killing efficiency against both gram-positive and gram-negative bacteria attached to them.

  4. Novel serine-based gemini surfactants as chemical permeation enhancers of local anesthetics: A comprehensive study on structure-activity relationships, molecular dynamics and dermal delivery.

    PubMed

    Teixeira, Raquel S; Cova, Tânia F G G; Silva, Sérgio M C; Oliveira, Rita; do Vale, M Luísa C; Marques, Eduardo F; Pais, Alberto A C C; Veiga, Francisco J B

    2015-06-01

    This work aims at studying the efficacy of a series of novel biocompatible, serine-based surfactants as chemical permeation enhancers for two different local anesthetics, tetracaine and ropivacaine, combining an experimental and computational approach. The surfactants consist of gemini molecules structurally related, but with variations in headgroup charge (nonionic vs. cationic) and in the hydrocarbon chain lengths (main and spacer chains). In vitro permeation and molecular dynamics studies combined with cytotoxicity profiles were performed to investigate the permeation of both drugs, probe skin integrity, and rationalize the interactions at molecular level. Results show that these enhancers do not have significant deleterious effects on the skin structure and do not cause relevant changes on cell viability. Permeation across the skin is clearly improved using some of the selected serine-based gemini surfactants, namely the cationic ones with long alkyl chains and shorter spacer. This is noteworthy in the case of ropivacaine hydrochloride, which is not easily administered through the stratum corneum. Molecular dynamics results provide a mechanistic view of the surfactant action on lipid membranes that essentially corroborate the experimental observations. Overall, this study suggests the viability of these serine-based surfactants as suitable and promising delivery agents in pharmaceutical formulations.

  5. A Novel Surface Structure Consisting of Contact-active Antibacterial Upper-layer and Antifouling Sub-layer Derived from Gemini Quaternary Ammonium Salt Polyurethanes.

    PubMed

    He, Wei; Zhang, Yi; Li, Jiehua; Gao, Yunlong; Luo, Feng; Tan, Hong; Wang, Kunjie; Fu, Qiang

    2016-01-01

    Contact-active antibacterial surfaces play a vital role in preventing bacterial contamination of artificial surfaces. In the past, numerous researches have been focused on antibacterial surfaces comprising of antifouling upper-layer and antibacterial sub-layer. In this work, we demonstrate a reversed surface structure which integrate antibacterial upper-layer and antifouling sub-layer. These surfaces are prepared by simply casting gemini quaternary ammonium salt waterborne polyurethanes (GWPU) and their blends. Due to the high interfacial energy of gemini quaternary ammonium salt (GQAS), chain segments containing GQAS can accumulate at polymer/air interface to form an antibacterial upper-layer spontaneously during the film formation. Meanwhile, the soft segments composed of polyethylene glycol (PEG) formed the antifouling sub-layer. Our findings indicate that the combination of antibacterial upper-layer and antifouling sub-layer endow these surfaces strong, long-lasting antifouling and contact-active antibacterial properties, with a more than 99.99% killing efficiency against both gram-positive and gram-negative bacteria attached to them. PMID:27561546

  6. A COMBINED VERY LARGE TELESCOPE AND GEMINI STUDY OF THE ATMOSPHERE OF THE DIRECTLY IMAGED PLANET, β PICTORIS b

    SciTech Connect

    Currie, Thayne; Jayawardhana, Ray; Burrows, Adam; Madhusudhan, Nikku; Fukagawa, Misato; Girard, Julien H.; Dawson, Rebekah; Murray-Clay, Ruth; Kenyon, Scott; Kuchner, Marc; Matsumura, Soko; Chambers, John; Bromley, Ben

    2013-10-10

    We analyze new/archival VLT/NaCo and Gemini/NICI high-contrast imaging of the young, self-luminous planet β Pictoris b in seven near-to-mid IR photometric filters, using advanced image processing methods to achieve high signal-to-noise, high precision measurements. While β Pic b's near-IR colors mimic those of a standard, cloudy early-to-mid L dwarf, it is overluminous in the mid-infrared compared to the field L/T dwarf sequence. Few substellar/planet-mass objects—i.e., κ And b and 1RXJ 1609B—match β Pic b's JHK{sub s}L' photometry and its 3.1 μm and 5 μm photometry are particularly difficult to reproduce. Atmosphere models adopting cloud prescriptions and large (∼60 μm) dust grains fail to reproduce the β Pic b spectrum. However, models incorporating thick clouds similar to those found for HR 8799 bcde, but also with small (a few microns) modal particle sizes, yield fits consistent with the data within the uncertainties. Assuming solar abundance models, thick clouds, and small dust particles ((a) = 4 μm), we derive atmosphere parameters of log (g) = 3.8 ± 0.2 and T{sub eff} = 1575-1650 K, an inferred mass of 7{sup +4}{sub -3} M{sub J} , and a luminosity of log(L/L{sub ☉}) ∼–3.80 ± 0.02. The best-estimated planet radius, ≈1.65 ± 0.06 R{sub J} , is near the upper end of allowable planet radii for hot-start models given the host star's age and likely reflects challenges constructing accurate atmospheric models. Alternatively, these radii are comfortably consistent with hot-start model predictions if β Pic b is younger than ≈7 Myr, consistent with a late formation well after its host star's birth ∼12{sup +8}{sub -4} Myr ago.

  7. Interactions of Divalent and Trivalent Metal Counterions with Anionic Sulfonate Gemini Surfactant and Induced Aggregate Transitions in Aqueous Solution.

    PubMed

    Liu, Zhang; Cao, Meiwen; Chen, Yao; Fan, Yaxun; Wang, Dong; Xu, Hai; Wang, Yilin

    2016-05-01

    Interactions of multivalent metal counterions with anionic sulfonate gemini surfactant 1,3-bis(N-dodecyl-N-propanesulfonate sodium)-propane (C12C3C12(SO3)2) and the induced aggregate transitions in aqueous solution have been studied. Divalent metal ions Ca(2+), Mg(2+), Cu(2+), Zn(2+), Mn(2+), Co(2+), and Ni(2+) and trivalent metal ions Al(3+), Fe(3+), and Cr(3+) were chosen. The results indicate that the critical micelle concentration (CMC) of C12C3C12(SO3)2 is greatly reduced by the ions, and the aggregate morphologies of C12C3C12(SO3)2 are adjusted by changing the nature and molar ratio of the metal ions. These metal ions can be classified into four groups because the ions in each group have very similar interaction mechanisms with C12C3C12(SO3)2: (I) Cu(2+) and Zn(2+); (II) Ca(2+), Mn(2+) and Mg(2+); (III) Ni(2+) and Co(2+); and (IV) Cr(3+), Al(3+) and Fe(3+). Cu(2+), Mg(2+), Ni(2+), and Al(3+) then were selected as representatives for each group to further study their interaction with C12C3C12(SO3)2. C12C3C12(SO3)2 interacts with the multivalent metal ions by electrostatic interaction and coordination interaction. C12C3C12(SO3)2 forms prolate micelles and plate-like micelles with Cu(2+), vesicles and wormlike micelles with Al(3+) or Ni(2+), and viscous three-dimensional network structure with Mg(2+). Moreover, precipitation does not take place in aqueous solution even at a high ion/surfactant ratio. The related mechanisms have been discussed. The present work provides guidance on how to apply the anionic surfactant into the solutions containing the multivalent metal ions, and those aggregates may have potential usage in separating heavy metal ions from aqueous solutions.

  8. THE GEMINI NICI PLANET-FINDING CAMPAIGN: THE FREQUENCY OF GIANT PLANETS AROUND YOUNG B AND A STARS

    SciTech Connect

    Nielsen, Eric L.; Liu, Michael C.; Chun, Mark; Ftaclas, Christ; Wahhaj, Zahed; Biller, Beth A.; Hayward, Thomas L.; Hartung, Markus; Alencar, Silvia H. P.; Artymowicz, Pawel; Boss, Alan; Clarke, Fraser; De Gouveia Dal Pino, Elisabete; Gregorio-Hetem, Jane; Kuchner, Marc; Lin, Douglas N. C.; and others

    2013-10-10

    We have carried out high contrast imaging of 70 young, nearby B and A stars to search for brown dwarf and planetary companions as part of the Gemini NICI Planet-Finding Campaign. Our survey represents the largest, deepest survey for planets around high-mass stars (≈1.5-2.5 M{sub ☉}) conducted to date and includes the planet hosts β Pic and Fomalhaut. We obtained follow-up astrometry of all candidate companions within 400 AU projected separation for stars in uncrowded fields and identified new low-mass companions to HD 1160 and HIP 79797. We have found that the previously known young brown dwarf companion to HIP 79797 is itself a tight (3 AU) binary, composed of brown dwarfs with masses 58{sup +21}{sub -20} M{sub Jup} and 55{sup +20}{sub -19} M{sub Jup}, making this system one of the rare substellar binaries in orbit around a star. Considering the contrast limits of our NICI data and the fact that we did not detect any planets, we use high-fidelity Monte Carlo simulations to show that fewer than 20% of 2 M{sub ☉} stars can have giant planets greater than 4 M{sub Jup} between 59 and 460 AU at 95% confidence, and fewer than 10% of these stars can have a planet more massive than 10 M{sub Jup} between 38 and 650 AU. Overall, we find that large-separation giant planets are not common around B and A stars: fewer than 10% of B and A stars can have an analog to the HR 8799 b (7 M{sub Jup}, 68 AU) planet at 95% confidence. We also describe a new Bayesian technique for determining the ages of field B and A stars from photometry and theoretical isochrones. Our method produces more plausible ages for high-mass stars than previous age-dating techniques, which tend to underestimate stellar ages and their uncertainties.

  9. 12. VIEW LOOKING SOUTH FROM PAVILION, SHOWING SOUTH ENTRANCE HOUSE, ...

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

    12. VIEW LOOKING SOUTH FROM PAVILION, SHOWING SOUTH ENTRANCE HOUSE, SOUTH WING, AND ENGINE HOUSE - Fairmount Waterworks, East bank of Schuylkill River, Aquarium Drive, Philadelphia, Philadelphia County, PA

  10. Caracterización espectro-fotométrica del entorno de una muestra de blazares en el óptico

    NASA Astrophysics Data System (ADS)

    Torres-Zafra, J.; Cellone, S.; Andruchow, I.

    2016-08-01

    BLLac objects are a class of active galactic nuclei characterized by presenting optical spectra without evident features; for this reason it is very difficult to determine their redshifts (). In this paper we perform a spectrophotometric study of the environment of three BLLac type objects: 3C 66A, PG1,553113 and PKS0332403, using data obtained with the Multi-Object Spectrograph and Camera, instrument at the 8m Gemini North and Gemini South telescopes. The analysis of these data allows us to detect galaxy cluster candidates with redshifts of , and respectively. Therefore, we discuss the probability of membership of the sources studied here to these structures.

  11. The Gemini Cluster Astrophysics Spectroscopic Survey (GCLASS): The Role of Environment and Self-regulation in Galaxy Evolution at z ~ 1

    NASA Astrophysics Data System (ADS)

    Muzzin, Adam; Wilson, Gillian; Yee, H. K. C.; Gilbank, David; Hoekstra, Henk; Demarco, Ricardo; Balogh, Michael; van Dokkum, Pieter; Franx, Marijn; Ellingson, Erica; Hicks, Amalia; Nantais, Julie; Noble, Allison; Lacy, Mark; Lidman, Chris; Rettura, Alessandro; Surace, Jason; Webb, Tracy

    2012-02-01

    We evaluate the effects of environment and stellar mass on galaxy properties at 0.85 Gemini Cluster Astrophysics Spectroscopic Survey. We confirm that for galaxies with log M */M ⊙ > 9.3 the well-known correlations between environment and properties such as star-forming fraction (f SF), star formation rate (SFR), specific SFR (SSFR), D n (4000), and color are already in place at z ~ 1. We separate the effects of environment and stellar mass on galaxies by comparing the properties of star-forming and quiescent galaxies at fixed environment and fixed stellar mass. The SSFR of star-forming galaxies at fixed environment is correlated with stellar mass; however, at fixed stellar mass it is independent of environment. The same trend exists for the D n (4000) measures of both the star-forming and quiescent galaxies and shows that their properties are determined primarily by their stellar mass, not by their environment. Instead, it appears that environment's primary role is to control the fraction of star-forming galaxies. Using the spectra we identify candidate poststarburst galaxies and find that those with 9.3 < log M */M ⊙ < 10.7 are 3.1 ± 1.1 times more common in high-density regions compared to low-density regions. The clear association of poststarbursts with high-density regions as well as the lack of a correlation between the SSFRs and D n (4000)s of star-forming galaxies with their environment strongly suggests that at z ~ 1 the environmental-quenching timescale must be rapid. Lastly, we construct a simple quenching model which demonstrates that the lack of a correlation between the D n (4000) of quiescent galaxies and their environment results naturally if self quenching dominates over environmental quenching at z > 1, or if the evolution of the self-quenching rate mirrors the evolution of the environmental-quenching rate at z > 1, regardless of which

  12. South Fork Latrine, oblique view showing south and east sides; ...

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

    South Fork Latrine, oblique view showing south and east sides; view northwest - Fort McKinley, South Fork Latrine, West side of East Side Drive, approximately 225 feet south of Weymouth Way, Great Diamond Island, Portland, Cumberland County, ME

  13. This is a CCD image taken 20 July UT (19 July CDT) at 02:00 UT (9:00pm CDT) with the 0.8m telescope

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is a CCD image taken 20 July UT (19 July CDT) at 02:00 UT (9:00pm CDT) with the 0.8m telescope of The University of Texas McDonald Observatory. An 893nm filter which isolates absorption by methane gas was used. This filter makes high cloud features appear bright. North is at the top and west is to the right. This image was obtained prior to sunset. In this image, impact sites from fragments L and G are clearly visible. This image was taken 4 hours after the L impact. The L impact site is the one nearest the west (right) limb. Notice the central dark region and the fountain pattern to the southwest. The G impact site is on the central meridian. It shows a central impact spot with a diffuse fan which also points to the southwest. The G impact occurred 4 Jupiter days before this image. The impact site for fragment H is just coming onto the east limb (left) and can be seen where it appears detached from the planet and may be a very high cloud. This image was taken by Dr. Wayne Pryor (University of Colorado), Dr. Chan Na (Southwest Research Institute) and Dr. Anita Cochran (University of Texas).

  14. New South Wales

    Atmospheric Science Data Center

    2013-04-16

    ... city of Sydney was clouded with smoke when more than 80 wildfires raged across the state of New South Wales. These images were captured ... at JPL December 30, 2001 - Smoke from wildfires covers New South Wales. project:  MISR ...

  15. Developing a Metadata Infrastructure to facilitate data driven science gateway and to provide Inspire/GEMINI compliance for CLIPC

    NASA Astrophysics Data System (ADS)

    Mihajlovski, Andrej; Plieger, Maarten; Som de Cerff, Wim; Page, Christian

    2016-04-01

    indicators Key is the availability of standardized metadata, describing indicator data and services. This will enable standardization and interoperability between the different distributed services of CLIPC. To disseminate CLIPC indicator data, transformed data products to enable impacts assessments and climate change impact indicators a standardized meta-data infrastructure is provided. The challenge is that compliance of existing metadata to INSPIRE ISO standards and GEMINI standards needs to be extended to further allow the web portal to be generated from the available metadata blueprint. The information provided in the headers of netCDF files available through multiple catalogues, allow us to generate ISO compliant meta data which is in turn used to generate web based interface content, as well as OGC compliant web services such as WCS and WMS for front end and WPS interactions for the scientific users to combine and generate new datasets. The goal of the metadata infrastructure is to provide a blueprint for creating a data driven science portal, generated from the underlying: GIS data, web services and processing infrastructure. In the presentation we will present the results and lessons learned.

  16. Latinos in the South.

    ERIC Educational Resources Information Center

    Shaw, Emily Elliott, Ed.

    2002-01-01

    This newsletter theme issue contains five articles about the growing Latino population in the South and its impact on communities, particularly in rural areas. "Social Capital of Mexican Communities in the South" (Ruben Hernandez-Leon, Victor Zuniga) argues that, to understand and advocate for Mexican newcomer communities in the South, scholars,…

  17. A Study of the Interaction between a Family of Gemini Amphiphilic Pseudopeptides and Model Monomolecular Film Membranes Formed with a Cardiolipin.

    PubMed

    Gorczyca, Marcelina; Korchowiec, Beata; Korchowiec, Jacek; Trojan, Sonia; Rubio-Magnieto, Jenifer; Luis, Santiago V; Rogalska, Ewa

    2015-06-01

    The interaction between five gemini amphiphilic pseudopeptides (GAPs) differing by the length of the central spacer and a model membrane lipid, 1,3-bis[1,2-dimyristoyl-sn-glycero-3-phospho]-sn-glycerol (cardiolipin) were studied with the aim to evaluate their possible antimicrobial properties. To this end, monomolecular films were formed at the air/water interface with pure cardiolipin or cardiolipin/GAPs mixtures; film properties were determined using surface pressure and surface potential measurements, as well as polarization-modulation infrared reflection-absorption spectroscopy. Moreover, to better understand the GAPs-phospholipid interaction at the molecular level, molecular dynamics simulations were performed. The results obtained indicate that the length of the central spacer has an effect on the interaction of GAPs with cardiolipin and on the properties of the lipid film. The GAPs with the longer linkers can be expected to be useful for biological membrane modification and for possible antimicrobial applications. PMID:25959677

  18. Surface modification of poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) elastomer via covalent immobilization of nonionic sugar-based Gemini surfactants.

    PubMed

    Xin, Zhirong; Du, Binbin; Yan, Shunjie; Du, Shanshan; Ding, Jiaotong; Yang, Zongfeng; Ren, Wanzhong

    2014-07-01

    Gemini surfactants (GS) with sugar-containing head-groups and different alkyl chains were successfully prepared. Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) elastomer was grafted with glycidyl methacrylate (GMA) by means of UV-induced graft polymerization, and then the pGMA-grafted film was chemically immobilized with the GS. The surface graft polymerization was confirmed by ATR-FTIR and XPS. The wettability and hemocompatibility of the modified surface were characterized by means of water contact angle, protein adsorption, and platelet adhesion assays. The results showed that amphiphilic surfactant-containing polymer surfaces presented protein-resistant behavior and anti-platelet adhesion after functionalization with GS, GS1 and GS2. Besides, the hemocompatibility of the modified surface deteriorated as the length of hydrophobic chain of GS increased.

  19. Surface modification of poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) elastomer via covalent immobilization of nonionic sugar-based Gemini surfactants.

    PubMed

    Xin, Zhirong; Du, Binbin; Yan, Shunjie; Du, Shanshan; Ding, Jiaotong; Yang, Zongfeng; Ren, Wanzhong

    2014-07-01

    Gemini surfactants (GS) with sugar-containing head-groups and different alkyl chains were successfully prepared. Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) elastomer was grafted with glycidyl methacrylate (GMA) by means of UV-induced graft polymerization, and then the pGMA-grafted film was chemically immobilized with the GS. The surface graft polymerization was confirmed by ATR-FTIR and XPS. The wettability and hemocompatibility of the modified surface were characterized by means of water contact angle, protein adsorption, and platelet adhesion assays. The results showed that amphiphilic surfactant-containing polymer surfaces presented protein-resistant behavior and anti-platelet adhesion after functionalization with GS, GS1 and GS2. Besides, the hemocompatibility of the modified surface deteriorated as the length of hydrophobic chain of GS increased. PMID:24854325

  20. A SLUGGS and Gemini/GMOS combined study of the elliptical galaxy M60: wide-field photometry and kinematics of the globular cluster system

    NASA Astrophysics Data System (ADS)

    Pota, Vincenzo; Brodie, Jean P.; Bridges, Terry; Strader, Jay; Romanowsky, Aaron J.; Villaume, Alexa; Jennings, Zach; Faifer, Favio R.; Pastorello, Nicola; Forbes, Duncan A.; Campbell, Ainsley; Usher, Christopher; Foster, Caroline; Spitler, Lee R.; Caldwell, Nelson; Forte, Juan C.; Norris, Mark A.; Zepf, Stephen E.; Beasley, Michael A.; Gebhardt, Karl; Hanes, David A.; Sharples, Ray M.; Arnold, Jacob A.

    2015-06-01

    We present new wide-field photometry and spectroscopy of the globular clusters (GCs) around NGC 4649 (M60), the third brightest galaxy in the Virgo cluster. Imaging of NGC 4649 was assembled from a recently obtained Hubble Space Telescope/Advanced Camera for Surveys mosaic, and new Subaru/Suprime-Cam and archival Canada-France-Hawaii Telescope/MegaCam data. About 1200 sources were followed up spectroscopically using combined observations from three multi-object spectrographs: Keck/Deep Imaging Multi-Object Spectrograph, Gemini/Gemini Multi-Object Spectrograph and Multiple Mirror Telescope/Hectospec. We confirm 431 unique GCs belonging to NGC 4649, a factor of 3.5 larger than previous data sets and with a factor of 3 improvement in velocity precision. We confirm significant GC colour bimodality and find that the red GCs are more centrally concentrated, while the blue GCs are more spatially extended. We infer negative GC colour gradients in the innermost 20 kpc and flat gradients out to large radii. Rotation is detected along the galaxy major axis for all tracers: blue GCs, red GCs, galaxy stars and planetary nebulae. We compare the observed properties of NGC 4649 with galaxy formation models. We find that formation via a major merger between two gas-poor galaxies, followed by satellite accretion, can consistently reproduce the observations of NGC 4649 at different radii. We find no strong evidence to support an interaction between NGC 4649 and the neighbouring spiral galaxy NGC 4647. We identify interesting GC kinematic features in our data, such as counter-rotating subgroups and bumpy kinematic profiles, which encode more clues about the formation history of NGC 4649.

  1. Analysis of mixed micellar behavior of cationic gemini alkanediyl-α,ω-bis(dimethylcetylammonium bromide) series with ionic and nonionic hydrotropes in aqueous medium at different temperatures.

    PubMed

    Khan, Iqrar Ahmad; Khanam, Ahmad Jahan; Sheikh, Mohmad Shafi; Kabir-ud-Din

    2011-12-29

    The interaction between cationic symmetrical gemini alkanediyl-α,ω-bis(dimethylcetylammonium bromide) series (16-s-16, s = 5, 6, abbreviated as G5 and G6) with hydrotropes (cationic: aniline hydrochloride, para-toluidine hydrochloride, and ortho-toluidine hydrochloride; nonionic: phenol, resorcinol, and pyrogallol) in aqueous medium has been investigated at four different temperatures ranging from 298.15 to 313.15 K. Different physicochemical parameters such as critical micelle concentration (cmc), interaction parameter (β(m), an energetic parameter that represents the excess Gibbs free energy of mixing), activity coefficients (f(i)), mole fraction of hydrotrope in mixed micelles at ideal mixing conditions (X(1)(ideal))(,) excess free energy of mixing (Δ(mix)G(E)), standard enthalpy (Δ(mic)H°), entropy (Δ(mic)S°), and Gibbs free energy (Δ(mic)G°) of micellization were evaluated and then intracompared. For further understanding, similar studies were carried out with their conventional counterpart cetyltrimethyl ammonium bromide (CTAB) and then compared. The bulk behaviors were explored using different theoretical models of Clint, Rubingh, and Motomura for justification and comparison of results of different binary combinations of hydrotropes with the gemini series and CTAB. Synergistic interaction was observed in all binary combinations at all temperatures in the micelles which decreases slightly with increasing temperature. This study will give insight into the selection of surfactants in different applications as their properties get modified by interaction with hydrotropes, thus influencing their solution behavior which, in turn, modifying the phase-forming behavior, microemulsion, liquid crystal forming systems, clouding phenomenon, cleaning, and laundry processes besides solubilization. The ability of hydrotropes to dramatically alter the solubility of other molecules in a medium can be exploited for the purpose of selective encapsulation and release

  2. Subseasonal teleconnections South America - South Africa

    NASA Astrophysics Data System (ADS)

    Grimm, Alice; Reason, Chris

    2016-04-01

    There is marked subseasonal variability over South America and southern Africa. Based on previous work showing that a teleconnection exists between the South American monsoon system and interannual summer rainfall variability over southern Africa, this study shows teleconnections between subseasonal variability over these landmasses. Observed daily gauge precipitation data for 1970-1999 are gridded to 1° resolution for South America and 2.5° for South Africa. At each grid point, anomalies of daily precipitation are calculated and submitted to a bandpass Lanczos filter to isolate subseasonal oscillations in the 20-90 day band. For each season, the filtered precipitation anomalies for the South African grid boxes are correlated with filtered precipitation anomalies in the grid boxes over South America. Lags from 0 up to 12 days are applied to the South African data, in order to investigate convection anomalies over South America that could produce atmospheric perturbations associated with South African precipitation anomalies. The significance of correlation between the filtered data takes autocorrelation into account and uses effective sample sizes. The results shown represent the best correlations for different climatic regimes such as the winter-rainfall dominated southwestern Cape, the all season rainfall South Coast and the summer-rainfall dominated Limpopo region. NCEP re-analyses are used to composite subseasonal anomalies in OLR, 200 hPa streamfunction, and vertically integrated moisture flux associated with precipitation anomaly above one standard deviation in the filtered series (positive phases) of the South African selected regions. The possible origin of the atmospheric circulation anomalies associated with those positive phases is determined using influence functions (IFs) of a vorticity equation model with a divergence source. The model is linearized about a realistic basic state and includes the divergence of the basic state and the advection of

  3. Terrorism in South Korea.

    PubMed

    Wang, Soon Joo; Choi, Jin Tae; Arnold, Jeffrey

    2003-01-01

    South Korea has experienced > 30 suspected terrorism-related events since 1958, including attacks against South Korean citizens in foreign countries. The most common types of terrorism used have included bombings, shootings, hijackings, and kidnappings. Prior to 1990, North Korea was responsible for almost all terrorism-related events inside of South Korea, including multiple assassination attempts on its presidents, regular kidnappings of South Korean fisherman, and several high-profile bombings. Since 1990, most of the terrorist attacks against South Korean citizens have occurred abroad and have been related to the emerging worldwide pattern of terrorism by international terrorist organizations or deranged individuals. The 1988 Seoul Olympic Games provided a major stimulus for South Korea to develop a national emergency response system for terrorism-related events based on the participation of multiple ministries. The 11 September 2001 World Trade Center and Pentagon attacks and the 2001 United States of America (US) anthrax letter attacks prompted South Korea to organize a new national system of emergency response for terrorism-related events. The system is based on five divisions for the response to specific types of terrorist events, involving conventional terrorism, bioterrorism, chemical terrorism, radiological terrorism, and cyber-terrorism. No terrorism-related events occurred during the 2002 World Cup and Asian Games held in South Korea. The emergency management of terrorism-related events in South Korea is adapting to the changing risk of terrorism in the new century.

  4. Terrorism in South Korea.

    PubMed

    Wang, Soon Joo; Choi, Jin Tae; Arnold, Jeffrey

    2003-01-01

    South Korea has experienced > 30 suspected terrorism-related events since 1958, including attacks against South Korean citizens in foreign countries. The most common types of terrorism used have included bombings, shootings, hijackings, and kidnappings. Prior to 1990, North Korea was responsible for almost all terrorism-related events inside of South Korea, including multiple assassination attempts on its presidents, regular kidnappings of South Korean fisherman, and several high-profile bombings. Since 1990, most of the terrorist attacks against South Korean citizens have occurred abroad and have been related to the emerging worldwide pattern of terrorism by international terrorist organizations or deranged individuals. The 1988 Seoul Olympic Games provided a major stimulus for South Korea to develop a national emergency response system for terrorism-related events based on the participation of multiple ministries. The 11 September 2001 World Trade Center and Pentagon attacks and the 2001 United States of America (US) anthrax letter attacks prompted South Korea to organize a new national system of emergency response for terrorism-related events. The system is based on five divisions for the response to specific types of terrorist events, involving conventional terrorism, bioterrorism, chemical terrorism, radiological terrorism, and cyber-terrorism. No terrorism-related events occurred during the 2002 World Cup and Asian Games held in South Korea. The emergency management of terrorism-related events in South Korea is adapting to the changing risk of terrorism in the new century. PMID:15074497

  5. 10. BUILDING: SECOND FLOOR (East Section), VIEW SOUTH: EAST, SOUTH ...

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

    10. BUILDING: SECOND FLOOR (East Section), VIEW SOUTH: EAST, SOUTH AND WEST WALLS OF COLD STORAGE, ALSO SHOWING REMNANTS OF COOLING PIPES - Boston Beer Company, 225-249 West Second Street, South Boston, Suffolk County, MA

  6. 13. OBLIQUE OF UNDERSIDE OF SOUTH TRUSS SPAN, SOUTH APPROACH ...

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

    13. OBLIQUE OF UNDERSIDE OF SOUTH TRUSS SPAN, SOUTH APPROACH SPAN, AND SOUTH PIER, SHOWING FLOOR SYSTEM AND BEARINGS. LOOKING NORTH. - Flintville Bridge, Spanning Broad Creek at Flintville Road (Maryland Route 623), Castleton, Harford County, MD

  7. 118. Stage basement. View, facing south, of the south hydraulic ...

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

    118. Stage basement. View, facing south, of the south hydraulic ram (type D) in the middle row. Photo was taken before the stage flooring was removed. - Auditorium Building, 430 South Michigan Avenue, Chicago, Cook County, IL

  8. 253. 441 SOUTH NINETEENTH STREET, WEST FRONT AND SOUTH SIDE, ...

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

    253. 441 SOUTH NINETEENTH STREET, WEST FRONT AND SOUTH SIDE, AND 1829, SOUTH FRONT AND WEST SIDE, TOWARD NORTHEAST - Russell Neighborhood, Bounded by Congress & Esquire Alley, Fifteenth & Twenty-first Streets, Louisville, Jefferson County, KY

  9. 3. SOUTH SIDE. Edwards Air Force Base, South Base ...

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

    3. SOUTH SIDE. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  10. 9. West elevation, west end of south wing wall, south ...

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

    9. West elevation, west end of south wing wall, south abutment and south railing panel looking east - Western Maryland Railway Bridge, Spanning Maryland Route 51 at Spring Gap, Cumberland, Allegany County, MD

  11. Efficient Cellular Knockdown Mediated by siRNA Nanovectors of Gemini Cationic Lipids Having Delocalizable Headgroups and Oligo-Oxyethylene Spacers.

    PubMed

    Martínez-Negro, María; Kumar, Krishan; Barrán-Berdón, Ana L; Datta, Sougata; Kondaiah, Paturu; Junquera, Elena; Bhattacharya, Santanu; Aicart, Emilio

    2016-08-31

    The use of small interfering RNAs (siRNAs) to silence specific genes is one of the most promising approaches in gene therapy, but it requires efficient nanovectors for successful cellular delivery. Recently, we reported liposomal gene carriers derived from a gemini cationic lipid (GCL) of the 1,2-bis(hexadecyl dimethyl imidazolium) oligo-oxyethylene series ((C16Im)2(C2H4O)nC2H4 with n = 1, 2, or 3) and 1,2-dioleyol phosphatidylethanolamine as highly efficient cytofectins for pDNA. On the basis of the satisfactory outcomes of the previous study, the present work focuses on the utility of coliposomes of these gemini lipids with the biocompatible neutral lipid mono oleoyl glycerol (MOG) as highly potent vectors for siRNA cellular transport in the presence of serum. The (C16Im)2(C2H4O)nC2H4/MOG-siRNA lipoplexes were characterized through (i) a physicochemical study (zeta potential, cryo-transmission electron microscopy, small-angle X-ray scattering, and fluorescence anisotropy) to establish the relationship between size, structure, fluidity, and the interaction between siRNA and the GCL/MOG gene vectors and (ii) a biological analysis (flow cytometry, fluorescence microscopy, and cell viability) to report the anti-GFP siRNA transfections in HEK 293T, HeLa, and H1299 cancer cell lines. The in vitro biological analysis confirms the cellular uptake and indicates that a short spacer, a very low molar fraction of GCL in the mixed lipid, and a moderate effective charge ratio of the lipoplex yielded maximum silencing efficacy. At these experimental conditions, the siRNA used in this work is compacted by the GCL/MOG nanovectors by forming two cubic structures (Ia3d and Pm3n) that are correlated with excellent silencing activity. These liposomal nanocarriers possess high silencing activity with a negligible cytotoxicity, which strongly supports their practical use for in vivo knockdown studies. PMID:27508330

  12. South Africa's Constitutional Change.

    ERIC Educational Resources Information Center

    Getman, Thomas

    1987-01-01

    Describes the striking dichotomy of South Africa's beauty and the squalor resulting from the apartheid policies of the government. Reviews reactions of black South Africans to recent constitutional changes and details efforts to secure more sweeping reform. Includes stories of several individuals who have taken actions which oppose the system of…

  13. Language in South Africa.

    ERIC Educational Resources Information Center

    Mesthrie, Rajend, Ed.

    This collection of 24 papers focuses on language and society in South Africa. Part 1, "The Main Language Groupings," includes (1) "South Africa: A Sociolinguistic Overview" (R. Mesthrie); (2) "The Khoesan Languages" (A. Traill); (3) "The Bantu Languages: Sociohistorical Perspectives" (Robert K. Herbert and Richard Bailey); (4) "Afrikaans:…

  14. South Persian Gulf Region

    NASA Technical Reports Server (NTRS)

    1981-01-01

    This oblique view of the south Persian Gulf region (26.0N, 54.0E) was taken over Iran looking west across the south Persian Gulf into the Trucial Coast of the United Arab Emirates and the prominent Qatar peninsula. Rich in petroleum resources, this region supplies much of the world's oil needs from its many ports and off shore loading facilities.

  15. Historical Capsule: South Africa.

    ERIC Educational Resources Information Center

    Cole, Robert

    1988-01-01

    Briefly traces the history of South Africa from British acquisition in 1815 through the creation of the Union of South Africa in 1910. Presents a chronicle of the year 1900 to show part of the European achievement in close-up. Lists accomplishments in literature, fine arts, science, technology, music, theater, and dance. (GEA)

  16. Dielectric Analysis for the Spherical and Rodlike Micelle Aggregates Formed from a Gemini Surfactant: Driving Forces of Micellization and Stability of Micelles.

    PubMed

    Wang, Shanshan; Zhao, Kongshuang

    2016-08-01

    The self-aggregation behavior of Gemini surfactant 12-2-12 (ethanediyl-1,2-bis(dimethyldodecylammonium bromide)) in water was investigated by dielectric relaxation spectroscopy (DRS) over a frequency range from 40 Hz to 110 MHz. Dielectric determination shows that well-defined spherical micelles formed when the concentration of the surfactant was above a critical micelle concentration CMC1 of 3 mM and rodlike micelles formed above CMC2, 16 mM. The formation mechanism of the spherical micelles and their transition mechanism to clubbed micelles were proposed by calculating the degree of counterion binding of the micelles. The interactions between the head groups and the hydrophobic chains of the surfactant led to the formation of the micelles, whereas the transition is mainly attributed to the interaction among the hydrophobic chains. By analyzing the dielectric relaxation observed at about 10(7) Hz based on the interface polarization theory, the permittivity and conductivity of micelle aggregates (spherical and clubbed) and volume fraction of micelles were calculated theoretically as well as the electrical properties of the solution medium. Furthermore, we also calculated the electrokinetic parameters of the micelle particle surface, surface conductivity, surface charge density, and zeta potential, using the relaxation parameters and phase parameters. On the basis of these results, the balance of forces controlling morphological transitions, interfacial electrokinetic properties, and the stability of the micelle aggregates was discussed. PMID:27396495

  17. Interaction of bovine serum albumin (BSA) with novel gemini surfactants studied by synchrotron radiation scattering (SR-SAXS), circular dichroism (CD), and nuclear magnetic resonance (NMR).

    PubMed

    Gospodarczyk, W; Szutkowski, K; Kozak, M

    2014-07-24

    The interaction of three dicationic (gemini) surfactants-3,3'-[1,6-(2,5-dioxahexane)]bis(1-dodecylimidazolium) chloride (oxyC2), 3,3'-[1,16-(2,15-dioxahexadecane)]bis(1-dodecylimidazolium) chloride (oxyC12), and 1,4-bis(butane)imidazole-1-yl-3-dodecylimidazolium chloride (C4)--with bovine serum albumin (BSA) has been studied by the use of small-angle X-ray scattering (SAXS), circular dichroism (CD), and (1)H nuclear magnetic resonance diffusometry. The results of CD studies show that the conformation of BSA was changed dramatically in the presence of all studied surfactants. The greater decrease (from 56 to 24%) in the α-helical structure of BSA was observed for oxyC2 surfactant. The radii of gyration estimated from SAXS data varied between 3 and 26 nm for the BSA/oxyC2 and BSA/oxyC12 systems. The hydrodynamic radius of the BSA/surfactant system estimated from NMR diffusometry varies between 5 and 11 nm for BSA/oxyC2 and 5 and 8 nm for BSA/oxyC12.

  18. POLARIZED LIGHT IMAGING OF THE HD 142527 TRANSITION DISK WITH THE GEMINI PLANET IMAGER: DUST AROUND THE CLOSE-IN COMPANION

    SciTech Connect

    Rodigas, Timothy J.; Weinberger, Alycia; Follette, Katherine B.; Close, Laird; Hines, Dean C.

    2014-08-20

    When giant planets form, they grow by accreting gas and dust. HD 142527 is a young star that offers a scaled-up view of this process. It has a broad, asymmetric ring of gas and dust beyond ∼100 AU and a wide inner gap. Within the gap, a low-mass stellar companion orbits the primary star at just ∼12 AU, and both the primary and secondary are accreting gas. In an attempt to directly detect the dusty counterpart to this accreted gas, we have observed HD 142527 with the Gemini Planet Imager in polarized light at Y band (0.95-1.14 μm). We clearly detect the companion in total intensity and show that its position and photometry are generally consistent with the expected values. We also detect a point source in polarized light that may be spatially separated by ∼ a few AU from the location of the companion in total intensity. This suggests that dust is likely falling onto or orbiting the companion. Given the possible contribution of scattered light from this dust to previously reported photometry of the companion, the current mass limits should be viewed as upper limits only. If the dust near the companion is eventually confirmed to be spatially separated, this system would resemble a scaled-up version of the young planetary system inside the gap of the transition disk around LkCa 15.

  19. Structure - membrane activity relationship in a family of peptide-based gemini amphiphiles: An insight from experimental and theoretical model systems.

    PubMed

    Korchowiec, Beata; Gorczyca, Marcelina; Korchowiec, Jacek; Rubio-Magnieto, Jenifer; Lotfallah, Ahmed H; Luis, Santiago V; Rogalska, Ewa

    2016-10-01

    A study of the interaction between five gemini amphiphilic valine-based pseudopeptides (GAPs) differing by the length of the central aliphatic spacer linking two amino acid subunits, and a model bacterial membrane lipid, 1,2-dimyristoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DMPG), is here presented. Pure DMPG, pure GAPs and mixed GAPs/DMPG monolayers were formed at the air-water interface using Langmuir technique. The properties of the Langmuir films were investigated using surface pressure measurements, polarization modulation-infrared reflection-absorption spectroscopy, and Brewster angle microscopy. The atomic level information concerning the orientation of molecules in the monolayer and hydration of the polar headgroups was obtained from molecular dynamics simulations. It was demonstrated that the length of the central spacer in the GAPs structure is important for the properties of the mixed films; the disorganization of the membrane increases with the length of the spacer. The latter point is important for developing possible antimicrobial agents based on GAPs.

  20. Photometric performance of LGS MCAO with science-based metrics: first results from Gemini/GeMS observations of Galactic globular clusters

    NASA Astrophysics Data System (ADS)

    Turri, Paolo; McConnachie, Alan W.; Stetson, Peter B.; Fiorentino, Giuliana; Andersen, David R.; Bono, Giuseppe; Véran, Jean-Pierre

    2014-08-01

    Multi-conjugate adaptive optics can achieve diffraction limited images over a field of arcminutes and is a central technology for the future ELTs: Gemini/GeMS is the first facility-class LGS MCAO system to operate. With it we have taken images in J and Ks bands of the globular cluster NGC 1851 for which we also have HST/ACS observations in the visible. In this paper we present the deepest to date near-infrared photometry of NGC 1851 providing a wide colour baseline CMD that reaches the lower main sequence to have a new insight into the stellar populations of this globular cluster. The use of the GGCs' lower main sequence knee to determine its age is one of the science drivers for the observation of GGCs with MCAO given its visibility in the infrared and because it requires high Strehl ratios to measure the faint stars' photometry. In addition to the stellar population analysis, these data allow to examine the photometric performance of the instrument using a large number of point sources distributed across the field. We analyze the photometric performance of the instrument and the field dependence of the PSF, a central part on the prediction and improvement of the performance of future LGS MCAO systems like NFIRAOS for the Thirty Meter Telescope.

  1. Conformational changes of DNA in the presence of 12-s-12 gemini surfactants (s=2 and 10). Role of the spacer's length in the interaction surfactant-polynucleotide.

    PubMed

    García, J P; Marrón, E; Martín, V I; Moyá, M L; Lopez-Cornejo, P

    2014-06-01

    A multifaceted study on the interaction of calf-thymus DNA with two different cationic gemini surfactants alkanediyl-α-ω-bis(dodecyldimethyl-amonium)bromide, 12-s-12,2Br(-) (with s=2, G2, and 10, G10) was carried out. The measurements were done at different molar ratios X=[surfactant]/[DNA]. Results show two different conformational changes in DNA: a first compaction of the polynucleotide corresponding to a partial conformational (not total) change of DNA from an extended coil state to a globular state that happens at the lower molar ratio X. A second change corresponds to a breaking of the partial condensation, that is, the transition from the compacted state to a new more extended conformation (for the higher X values) different to the initial extension. According to circular dichroism spectra and dynamic light scattering measurements, this new state of DNA seems to be similar to a ψ-phase. Measurements confirm that interactions involved in the compaction are different to those previously obtained for the analog surfactant CTAB. X values at which the conformational changes happen depend on the length of the spacer in the surfactant along with the charge of the polar heads.

  2. THE GEMINI NICI PLANET-FINDING CAMPAIGN: DISCOVERY OF A CLOSE SUBSTELLAR COMPANION TO THE YOUNG DEBRIS DISK STAR PZ Tel

    SciTech Connect

    Biller, Beth A.; Liu, Michael C.; Wahhaj, Zahed; Dupuy, Trent J.; Ftaclas, Christ; Nielsen, Eric L.; Close, Laird M.; Males, Jared; Skemer, Andrew; Hayward, Thomas L.; Hartung, Markus; Chun, Mark; Clarke, Fraser; Tecza, Matthias; Thatte, Niranjan; Reid, I. Neill; Shkolnik, Evgenya L.; Alencar, Silvia H. P.; Artymowicz, Pawel

    2010-09-01

    We report the discovery of a tight substellar companion to the young solar analog PZ Tel, a member of the {beta} Pic moving group observed with high-contrast adaptive optics imaging as part of the Gemini Near-Infrared Coronagraphic Imager Planet-Finding Campaign. The companion was detected at a projected separation of 16.4 {+-} 1.0 AU (0.''33 {+-} 0.''01) in 2009 April. Second-epoch observations in 2010 May demonstrate that the companion is physically associated and shows significant orbital motion. Monte Carlo modeling constrains the orbit of PZ Tel B to eccentricities >0.6. The near-IR colors of PZ Tel B indicate a spectral type of M7 {+-} 2 and thus this object will be a new benchmark companion for studies of ultracool, low-gravity photospheres. Adopting an age of 12{sup +8} {sub -4} Myr for the system, we estimate a mass of 36 {+-} 6 M {sub Jup} based on the Lyon/DUSTY evolutionary models. PZ Tel B is one of the few young substellar companions directly imaged at orbital separations similar to those of giant planets in our own solar system. Additionally, the primary star PZ Tel A shows a 70 {mu}m emission excess, evidence for a significant quantity of circumstellar dust that has not been disrupted by the orbital motion of the companion.

  3. [Travel destinations South America].

    PubMed

    Neumayr, Andreas

    2013-06-01

    The number of tourists visiting South America comprises only a small fraction of the worldwide stream of international travellers (approx. 980 Mio. in 2011). Nevertheless, their number has markedly increased in the last years (2000: 15.3 Mio.; 2005: 18.3 Mio.; 2010: 23.6 Mio.; 2011: 26.1 Mio.) and in 2011, South America was ranked top in the list of worldwide travel destinations with the highest increase in annual international tourist arrivals (10.4 %)[1]. This article aims at providing a practice-oriented overview on vaccinations, malaria prophylaxis, and other relevant health risks to be considered when counselling travellers visiting South America.

  4. Neosporosis in South America.

    PubMed

    Moore, D P

    2005-01-20

    This work gathers reports about Neospora-infections in South America. Neospora-infections have been reported from Argentina, Brazil, Chile, Paraguay, Peru and Uruguay. Evidence of exposure to N. caninum was mentioned in cattle, goats, sheep, dogs, cats, water buffaloes, alpacas, llamas, South American opossums, wolves and other wild canids. No antibodies were found in horses. Interesting epidemiological and pathological data were described. Two isolations were performed from dogs, one from cattle, and recently five from water buffaloes. Since the cattle industry is important in South America and reproductive losses caused by Neospora-infection have been identified, more investigations are needed in order to understand its epidemiology and control the disease.

  5. View looking south out the door opening from the south ...

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

    View looking south out the door opening from the south side of the rotunda extension onto the "dog house" or vestibule positioned where the west Verandah of the south wing turns ninety degrees and continues along the south wall of the central pavilion. - U. S. Naval Asylum, Biddle Hall, Gray's Ferry Avenue, Philadelphia, Philadelphia County, PA

  6. Ladybugs of South Dakota

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Images of the 79 species of Coccinellidae occurring in South Dakota are presented in taxonomic order. Information on each species includes genus-species name, sub-familial classification, and lengths and widths....

  7. South African Particulates

    Atmospheric Science Data Center

    2013-04-16

    ... Extensive burning of grass and shrubland for land management and agriculture comprises a principal source of these aerosols. ... 2000 - Airborne particulates over South Africa. project:  MISR category:  gallery date:  ...

  8. Mercury's South Polar Region

    NASA Video Gallery

    This animation shows 89 wide-angle camera (WAC) images of Mercury’s south polar region acquired by the Mercury Dual Imaging System (MDIS) over one complete Mercury solar day (176 Earth days). Thi...

  9. Lunar South Pole Illumination

    NASA Video Gallery

    Simulated illumination conditions over the lunar South Pole region, from ~80°S to the pole. The movie runs for 28 days, centered on the LCROSS impact date on October 9th, 2009. The illumination ca...

  10. Dust in active galactic nuclei. Mid-infrared T-ReCS/Gemini spectra using the new RedCan pipeline

    NASA Astrophysics Data System (ADS)

    González-Martín, O.; Rodríguez-Espinosa, J. M.; Díaz-Santos, T.; Packham, C.; Alonso-Herrero, A.; Esquej, P.; Ramos Almeida, C.; Mason, R.; Telesco, C.

    2013-05-01

    Context. The unified model of active galactic nuclei (AGN) claims that the properties of AGN depend on the viewing angle of the observer with respect to a toroidal distribution of dust surrounding the nucleus. Both the mid-infrared (MIR) attenuation and continuum luminosity are expected to be related to dust associated with the torus. Therefore, isolating the nuclear component is essential for studying the MIR emission of AGN. Aims: This work is aimed at studying the MIR emission of AGN with the highest spatial resolution available to date, isolating its contribution from extended emission. We would like to address three fundamental questions: (1) how important is the AGN contribution to the MIR spectrum; (2) where dust attenuation arises; and (3) how does spatial resolution affect these issues. Methods: We compiled all the T-ReCS spectra (Gemini Observatory) available in the N-band for 22 AGN: 5 Type-1 and 17 Type-2 AGN. The high angular resolution of the T-ReCS spectra allowed us to probe physical regions of 57 pc (median). We used a novel pipeline called RedCan capable of producing flux- and wavelength-calibrated spectra for the CanariCam (GTC) and T-ReCS (Gemini) instruments. We measured the fine-structure [S IV] at 10.5 μm and the PAH at 11.3 μm line strengths, together with the silicate absorption/emission features. We also compiled Spitzer/IRS spectra to understand how spatial resolution influences the results. We complemented our sample with the results of 19 VISIR/VLT spectra (Paranal Observatory) and 20 nearby, highly obscured AGN (NH > 1.5 × 1024 cm-2) Spitzer spectra. Results: The 11.3 μm PAH feature is only clearly detected in the nuclear spectra of two AGN, while it is more common in the Spitzer data. For those two objects, the AGN emission in NGC 7130 accounts for more than 80% of the MIR continuum at 12 μm, while in the case of NGC 1808 the AGN does not dominate the MIR emission. This is confirmed by the correlation between the MIR and X

  11. The Next Generation Virgo Cluster Survey. XII. Stellar Populations and Kinematics of Compact, Low-mass Early-type Galaxies from Gemini GMOS-IFU Spectroscopy

    NASA Astrophysics Data System (ADS)

    Guérou, Adrien; Emsellem, Eric; McDermid, Richard M.; Côté, Patrick; Ferrarese, Laura; Blakeslee, John P.; Durrell, Patrick R.; MacArthur, Lauren A.; Peng, Eric W.; Cuillandre, Jean-Charles; Gwyn, Stephen

    2015-05-01

    We present Gemini Multi Object Spectrograph integral-field unit (GMOS-IFU) data of eight compact, low-mass early-type galaxies (ETGs) in the Virgo cluster. We analyze their stellar kinematics and stellar population and present two-dimensional maps of these properties covering the central 5″ × 7″ region. We find a large variety of kinematics, from nonrotating to highly rotating objects, often associated with underlying disky isophotes revealed by deep images from the Next Generation Virgo Cluster Survey. In half of our objects, we find a centrally concentrated younger and more metal-rich stellar population. We analyze the specific stellar angular momentum through the λR parameter and find six fast rotators and two slow rotators, one having a thin counterrotating disk. We compare the local galaxy density and stellar populations of our objects with those of 39 more extended low-mass Virgo ETGs from the SMAKCED survey and 260 massive (M > 1010 {{M}⊙ }) ETGs from the ATLAS3D sample. The compact low-mass ETGs in our sample are located in high-density regions, often close to a massive galaxy, and have, on average, older and more metal-rich stellar populations than less compact low-mass galaxies. We find that the stellar population parameters follow lines of constant velocity dispersion in the mass-size plane, smoothly extending the comparable trends found for massive ETGs. Our study supports a scenario where low-mass compact ETGs have experienced long-lived interactions with their environment, including ram-pressure stripping and gravitational tidal forces, that may be responsible for their compact nature.

  12. Gemini long-slit observations of luminous obscured quasars: Further evidence for an upper limit on the size of the narrow-line region

    SciTech Connect

    Hainline, Kevin N.; Hickox, Ryan C.; Greene, Jenny E.; Myers, Adam D.; Zakamska, Nadia L.; Liu, Guilin; Liu, Xin

    2014-05-20

    We examine the spatial extent of the narrow-line regions (NLRs) of a sample of 30 luminous obscured quasars at 0.4 < z < 0.7 observed with spatially resolved Gemini-N GMOS long-slit spectroscopy. Using the [O III] λ5007 emission feature, we estimate the size of the NLR using a cosmology-independent measurement: the radius where the surface brightness falls to 10{sup –15} erg s{sup –1} cm{sup –2} arcsec{sup –2}. We then explore the effects of atmospheric seeing on NLR size measurements and conclude that direct measurements of the NLR size from observed profiles are too large by 0.1-0.2 dex on average, as compared to measurements made to best-fit Sérsic or Voigt profiles convolved with the seeing. These data, which span a full order of magnitude in IR luminosity (log (L {sub 8} {sub μm}/erg s{sup –1}) = 44.4-45.4), also provide strong evidence that there is a flattening of the relationship between NLR size and active galactic nucleus luminosity at a seeing-corrected size of ∼7 kpc. The objects in this sample have high luminosities which place them in a previously under-explored portion of the size-luminosity relationship. These results support the existence of a maximal size of the NLR around luminous quasars; beyond this size, there is either not enough gas or the gas is over-ionized and does not produce enough [O III] λ5007 emission.

  13. THE GEMINI/HST CLUSTER PROJECT: STRUCTURAL AND PHOTOMETRIC PROPERTIES OF GALAXIES IN THREE z = 0.28-0.89 CLUSTERS

    SciTech Connect

    Chiboucas, Kristin; Joergensen, Inger; Barr, Jordi; Collobert, Maela; Davies, Roger; Flint, Kathleen E-mail: ijorgensen@gemini.edu E-mail: maela.collobert@gmail.com E-mail: kflint@nationalpostdoc.org

    2009-10-01

    We present the data processing and analysis techniques we are using to determine the structural and photometric properties of galaxies in our Gemini/HST Galaxy Cluster Project sample. The goal of this study is to understand cluster galaxy evolution in terms of scaling relations and structural properties of cluster galaxies at redshifts 0.15 < z < 1.0. To derive parameters such as total magnitude, half-light radius, effective surface brightness, and Sersic n, we fit r {sup 1/4} law and Sersic function two-dimensional surface brightness profiles to each of the galaxies in our sample. Using simulated galaxies, we test how the assumed profile affects the derived parameters and how the uncertainties affect our Fundamental Plane results. We find that while fitting galaxies that have Sersic index n < 4 with r {sup 1/4} law profiles systematically overestimates the galaxy radius and flux, the combination of profile parameters that enter the Fundamental Plane has uncertainties that are small. Average systematic offsets and associated random uncertainties in magnitude and log r{sub e} for n>2 galaxies fitted with r {sup 1/4} law profiles are -0.1 {+-} 0.3 and 0.1 {+-} 0.2, respectively. The combination of effective radius and surface brightness, log r{sub e} - {beta}log (I) {sub e}, that enters the Fundamental Plane produces offsets smaller than -0.02 {+-} 0.10. This systematic error is insignificant and independent of galaxy magnitude or size. A catalog of photometry and surface brightness profile parameters is presented for three of the clusters in our sample, RX J0142.0+2131, RX J0152.7-1357, and RX J1226.9+3332 at redshifts 0.28, 0.83, and 0.89, respectively.

  14. Thermodynamics of micelle formation of the counterion coupled gemini surfactant Bis(4-(2-dodecyl)benzenesulfonate)-Jeffamine salt and its dynamic adsorption on sandstone.

    PubMed

    Páhi, Annamária B; Király, Zoltán; Mastalir, Agnes; Dudás, József; Puskás, Sándor; Vágó, Arpád

    2008-12-01

    A novel counterion-coupled gemini (cocogem) surfactant, DBSJ, was synthetized via the 2:1 coupling reaction between 4-(2-dodecyl)benzenesulfonic acid (Lutensit A-LBS) and polypropyleneglycol-bis(2-aminopropyl) ether (Jeffamine D230). The surfactant had a polydispersity index of Mw/Mn = 1.04, as determined by electrospray-ionization mass spectrometry. The micellar properties of DBSJ in water were investigated in the temperature range 283-348 K by conductometry and titration microcalorimetry. The critical micelle concentration (cmc) of the cocogem was found to be more than 1 order of magnitude less than that of monomeric sodium 4-(2-dodecyl)benzenesulfonate (SDBS). The mean degree of dissociation in the temperature range studied proved to be alpha = 0.39. The calorimetric enthalpies of micelle formation agreed well with the enthalpies calculated via the van't Hoff relation. The cmc versus T curve passes through a minimum just below room temperature, after which the micelle formation changes from endothermic to exothermic. The Gibbs free energy of micelle formation was nearly constant as the temperature was increased, due to enthalpy/entropy compensation. The isotherm for DBSJ adsorption from aqueous solution onto sandstone was determined by continuous flow frontal analysis solid/liquid chromatography at 298 K and 60 bar. The adsorption of DBSJ on sandstone followed an S-type isotherm. Surface aggregation occurred over an extended range of concentration. Surface saturation was reached at a solution concentration more than 1 order of magnitude less than for monomeric SDBS. This finding is a point of concern in the chemical flooding of oil reservoir rocks to enhance oil recovery.

  15. 1 to 2.4 microns spectrum and orbital properties of the Giant Planet Beta Pictoris b obtained with the Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Pueyo, Laurent; Chilcote, Jeffrey; Millar-Blanchaer, Max; Barman, Travis; Fitzgerald, Michael P.; Graham, James R.; Larkin, James; Kalas, Paul G.; dawson, Rebekah; Wang, Jason; Perrin, Marshall; Moon, Dae-Sik; Macintosh, Bruce

    2015-12-01

    We present a low-resolution multi-band spectrum of the planetary companion to the nearby young star beta Pictoris using the Gemini Planet Imager (GPI). GPI is designed to image and provide low-resolution spectra of Jupiter sized, self-luminous planetary companions around young nearby stars. While H-bandis the primary workhorse for the GPI Exoplanet Survey, the instrument is capable of observing in the near infrared covering Y, J, H, and K bands. These observations of Beta Pic Pictoris b were taken covering multiple bands as part of GPI’s verification and commissioning phase in 2013 and 2014. Using atmospheric models along with the H-band data we recently reported an effective temperature of 1600-1700 K and a surface gravity of log (g) = 3.5-4.5 (cgs units). A similar exercise was also carried out by an independent team using the J band data, and did yield similar conclusions. These values agree well with ”hot-start” predictions from planetary evolution models for a gas giant with mass between 10 and 12 M Jup and age between 10 and 20 Myr. Here we revisit these conclusions in light of a joint analysis of these two datasets along with the longer wavelength GPI spectrum in K band, and present refined constraints on the atmospheric properties of this giant planet. In addition, we present an updated orbit for Beta Pictoris b based on astrometric measurements taken using commissioning and subsequent monitoring observations, spanning 14 months. The planet has a semi-major axis of 9.2 (+1.5 -0.4) AU, with an eccentricity e≤ 0.26. The position angle of the ascending node is Ω=31.75 deg±0.15, offset from both the outer main disk and the inner disk seen in the GPI image. We finally discuss these properties in the context of planet-disk dynamical interactions.

  16. Anaglyph, South America

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This anaglyph (stereoscopic view) of South America was generated with data from the Shuttle Radar Topography Mission (SRTM). It is best viewed at or near full resolution with anaglyph glasses. For this broad view the resolution of the data was first reduced to 30 arcseconds (about 928 meters north-south but variable east-west), matching the best previously existing global digital topographic data set called GTOPO30. The data were then resampled to a Mercator projection with approximately square pixels (about one kilometer, or 0.6 miles, on each side). Even at this decreased resolution the variety of landforms comprising the South American continent is readily apparent.

    Topographic relief in South America is dominated by the Andes Mountains, which extend all along the Pacific Coast. These mountains are created primarily by the convergence of the Nazca and South American tectonic plates. The Nazca Plate, which underlies the eastern Pacific Ocean, slides under western South America resulting in crustal thickening, uplift, and volcanism. Another zone of plate convergence occurs along the northwestern coast of South America where the Caribbean Plate also slides under the South American Plate and forms the northeastern extension of the Andes Mountains.

    East of the Andes, much of northern South America drains into the Amazon River, the world's largest river in terms of both watershed area and flow volume. Topographic relief is very low in much of the Amazon Basin but SRTM data provide an excellent detailed look at the basin's three-dimensional drainage pattern, including the geologic structural trough (syncline) that hosts the eastern river channel.

    North of the Amazon, the Guiana Highlands commonly stand in sharp contrast to the surrounding lowlands, indeed hosting the world's tallest waterfall, Angel Falls (979 meters or 3212 feet). Folded and fractured bedrock structures are distinctive in the topographic pattern.

    South of the Amazon, the Brazilian

  17. South China Sea.

    PubMed

    Morton, B; Blackmore, G

    2001-12-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the

  18. South China Sea.

    PubMed

    Morton, B; Blackmore, G

    2001-12-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the

  19. South Polar Scarps

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-438, 31 July 2003

    The terrain of the south polar residual ice cap, made up mostly of frozen carbon dioxide, has come to be known by many as 'swiss cheese terrain,' because many areas of the cap resemble slices of swiss cheese. However, not all of the south polar cap looks like a tasty lunch food. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a series of curving scarps formed by erosion and sublimation of carbon dioxide from the south polar cap. This area is located near 86.3oS, 51.2oW. The image is illuminated by sunlight from the upper left; the area is about 1.5 km (0.9 mi) wide.

  20. South Polar Variety

    NASA Technical Reports Server (NTRS)

    2005-01-01

    28 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a view of linear troughs and mesas formed in the frozen carbon dioxide of the martian south polar residual cap. This image, obtained in May 2005, is a reminder that not all of the south polar cap landscapes resemble 'swiss cheese.'

    Location near: 86.7oS, 24.8oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  1. South Polar Cap

    NASA Technical Reports Server (NTRS)

    2005-01-01

    8 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows landforms created by sublimation processes on the south polar residual cap of Mars. The bulk of the ice in the south polar residual cap is frozen carbon dioxide.

    Location near: 86.6oS, 342.2oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  2. 1. WEST AND SOUTH SIDES, FROM APPROXIMATELY 25 FEET SOUTH ...

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

    1. WEST AND SOUTH SIDES, FROM APPROXIMATELY 25 FEET SOUTH OF SOUTHEASTERN CORNER OF BUILDING 441-B, LOOKING NORTHEAST. - Oakland Naval Supply Center, Heating Plant, On Northwest Corner of K Street & Fifth Street, Oakland, Alameda County, CA

  3. 5. Mispillion Lighthouse, South Elevation Mispillion Lighthouse, South bank ...

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

    5. Mispillion Lighthouse, South Elevation - Mispillion Lighthouse, South bank of Mispillion River at its confluence with Delaware River at northeast end of County Road 203, 7 miles east of Milford, Milford, Sussex County, DE

  4. View of south entrance to #157 through south breezeway arches ...

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

    View of south entrance to #157 through south breezeway arches - National Home for Disabled Volunteer Soldiers, Pacific Branch, Mental Health Buildings, 11301 Wilshire Boulevard, West Los Angeles, Los Angeles County, CA

  5. DETAIL VIEW, OXEYE WINDOW, SOUTH WALL OF SOUTH GARRET. THE ...

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

    DETAIL VIEW, OX-EYE WINDOW, SOUTH WALL OF SOUTH GARRET. THE MUNTIN PATTERN USED IN THIS WINDOW WAS REFERRED TO AS “GOTHIC” IN THE EIGHTEENTH CENTURY - The Woodlands, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

  6. 64. Credit JTL. West and south elevations from across South ...

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

    64. Credit JTL. West and south elevations from across South Battle Creek. Note penstock descending hill in background and new powerhouse construction in foreground. - Battle Creek Hydroelectric System, Battle Creek & Tributaries, Red Bluff, Tehama County, CA

  7. 18. WEST PART OF SOUTH SIDE OF SOUTH WING AND ...

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

    18. WEST PART OF SOUTH SIDE OF SOUTH WING AND PART OF REAR OF FRONT (WEST) PORTION OF BUILDING, LOOKING NORTHWEST (Harms) - Dairy Industry Building, Iowa State University campus, Ames, Story County, IA

  8. Detail of south wing south elevation wall section; camera facing ...

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

    Detail of south wing south elevation wall section; camera facing northwest - Mare Island Naval Shipyard, Defense Electronics Equipment Operating Center, I Street, terminus west of Cedar Avenue, Vallejo, Solano County, CA

  9. INTERIOR FOURTH FLOOR, SOUTH HALF, LOOKING SOUTH. NOTE MUSHROOM COLUMNS ...

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

    INTERIOR FOURTH FLOOR, SOUTH HALF, LOOKING SOUTH. NOTE MUSHROOM COLUMNS AND CEILING HAS WOODEN NAILERS. - Colt Fire Arms Company, North Armory, 36-150 Huyshope Avenue, 17-170 Van Dyke Avenue, 49 Vredendale Avenue, Hartford, Hartford County, CT

  10. 27. INTERIOR, FIRST FLOOR, SOUTH ENTRANCE, SOUTH LOBBY, DETAIL OF ...

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

    27. INTERIOR, FIRST FLOOR, SOUTH ENTRANCE, SOUTH LOBBY, DETAIL OF BRONZE SEAL IN FLOOR (4' x 5' negative; 8' x 10' print) - U.S. Department of the Interior, Eighteenth & C Streets Northwest, Washington, District of Columbia, DC

  11. 7. SOUTH ELEVATION OF BUILDING 262 (SOUTH SENTRY POST) IN ...

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

    7. SOUTH ELEVATION OF BUILDING 262 (SOUTH SENTRY POST) IN STORAGE AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

  12. Looking South at south End of Green Room Including Scrubber ...

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

    Looking South at south End of Green Room Including Scrubber for Incinerator within Recycle Recovery Building - Hematite Fuel Fabrication Facility, Recycle Recovery Building, 3300 State Road P, Festus, Jefferson County, MO

  13. 22. VIEW SOUTH, INTERIOR OF SOUTH PIT, SHOWING FINAL STEP ...

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

    22. VIEW SOUTH, INTERIOR OF SOUTH PIT, SHOWING FINAL STEP IN GEARING THAT DRIVES OPERATING WHEEL, WITH HYDRAULIC SHAFT BRAKE - Mystic River Bridge, Spanning Mystic River at U.S. Route 1, Groton, New London County, CT

  14. 13. South room first floor. View looking southwest. South addition ...

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

    13. South room first floor. View looking southwest. South addition visible through doorway. - Fort Hill Farm, Mansion, West of Staunton (Roanoke) River between Turkey & Caesar's Runs, Clover, Halifax County, VA

  15. 14. South room first floor. View looking south. East porch ...

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

    14. South room first floor. View looking south. East porch visible through window. - Fort Hill Farm, Mansion, West of Staunton (Roanoke) River between Turkey & Caesar's Runs, Clover, Halifax County, VA

  16. 170. GWMP SOUTH OF GREAT HUNTING CREEK LOOKING SOUTH. (NOTE ...

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

    170. GWMP SOUTH OF GREAT HUNTING CREEK LOOKING SOUTH. (NOTE ASPHALT PAVEMENT AND FILLED LAND) - George Washington Memorial Parkway, Along Potomac River from McLean to Mount Vernon, VA, Mount Vernon, Fairfax County, VA

  17. View south; detail view of column A13, south bay ...

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

    View south; detail view of column A13, south bay - Naval Base Philadelphia-Philadelphia Naval Shipyard, Foundry-Propeller Shop, North of Porter Avenue, west of Third Street West, Philadelphia, Philadelphia County, PA

  18. 12. VIEW OF SOUTH SIDE OF SOUTH WING OF TECHWOOD ...

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

    12. VIEW OF SOUTH SIDE OF SOUTH WING OF TECHWOOD DORMITORY, LOOKING NORTHWEST FROM NEAR CENTER OF SOUTH SIDE. ORIGINAL CASEMENT WINDOWS HAVE BEEN REPLACED WITH SASH WINDOWS, SOME WITH SCREENS. - Techwood Homes, McDaniel Dormitory, 581-587 Techwood Drive, Atlanta, Fulton County, GA

  19. 51. VIEW SOUTH, WIDE VIEW INTO SOUTH STREET RAMP NECKDOWN, ...

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

    51. VIEW SOUTH, WIDE VIEW INTO SOUTH STREET RAMP NECKDOWN, SHOWING UNDERSIDE FRAMING OF CENTER RAMP SECTION AND BOTH EAST AND WEST SPLITS, AND STEEL BENTS - Route 1 Extension, Southbound Viaduct, Spanning Conrail Yards, Wilson Avenue, Delancy Street, & South Street on Routes 1 & 9 Southbound, Newark, Essex County, NJ

  20. 7. DETAIL, LOOKING SOUTH, INTERIOR OF SOUTH ARCH, SHOWING DRAINAGE ...

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

    7. DETAIL, LOOKING SOUTH, INTERIOR OF SOUTH ARCH, SHOWING DRAINAGE HOLE IN THE WEST END OF THE SOUTH WALL AND VERTICAL QUARRY DRILLING HOLES ON THE STONE FACE - Mulladay Hollow Bridge, Spanning Mulladay Hollow Creek at County Road No.61, Eureka Springs, Carroll County, AR