WorldWideScience

Sample records for circumstellar environments experiment

  1. White dwarf atmospheres and circumstellar environments

    CERN Document Server

    Hoard, Donald W

    2012-01-01

    Written by selected astronomers at the forefront of their fields, this timely and novel book compiles the latest results from research on white dwarf stars, complementing existing literature by focusing on fascinating new developments in our understanding of the atmospheric and circumstellar environments of these stellar remnants. Complete with a thorough refresher on the observational characteristics and physical basis for white dwarf classification, this is a must-have resource for researchers interested in the late stages of stellar evolution, circumstellar dust and nebulae, and the future

  2. The Circumstellar Environment of VY CMa

    Science.gov (United States)

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

    1999-05-01

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

  3. Mid-IR Observations of Mira Circumstellar Environment

    OpenAIRE

    Marengo, Massimo; Karovska, Margarita; Fazio, Giovanni G.; Hora, Joseph L.; Hoffmann, William F.; Dayal, Aditya; Deutsch, Lynne K.

    2001-01-01

    This paper presents results from high-angular resolution mid-IR imaging of the Mira AB circumbinary environment using the MIRAC3 camera at the NASA Infrared Telescope Facility (IRTF). We resolved the dusty circumstellar envelope at 9.8, 11.7 and 18 micron around Mira A (o Ceti), and measured the size of the extended emission. Strong deviations from spherical symmetry are detected in the images of Mira AB system, including possible dust clumps in the direction of the companion (Mira B). These ...

  4. Astrobiological Effects of Stellar Radiation in Circumstellar Environments

    Science.gov (United States)

    Cuntz, Manfred; Gurdemir, Levent; Guinan, Edward F.; Kurucz, Robert L.

    2006-10-01

    The centerpiece of all life on Earth is carbon-based biochemistry. Previous scientific research has suggested that biochemistry based on carbon may also play a decisive role in extraterrestrial life forms, i.e., alien life outside of Earth, if existent. In the following, we explore if carbon-based macromolecules (such as DNA) in the environments of stars other than the Sun are able to survive the effects of energetic stellar radiation, such as UV-C in the wavelength band between 200 and 290 nm. We focus on main-sequence stars akin to the Sun, but of hotter (F-type stars) and cooler (K- and M-type stars) surface temperature. Emphasis is placed on investigating the radiative environment in stellar habitable zones (HZs). Stellar habitable zones have an important relevance in astrobiology because they constitute circumstellar regions in which a planet of suitable size can have surface temperatures for water to exist in liquid form.

  5. A Rigidly Rotating Magnetosphere Model for the Circumstellar Environments of Magnetic OB Stars

    Science.gov (United States)

    Townsend, R.; Owocki, S.; Groote, D.

    2005-11-01

    We report on a new model for the circumstellar environments of rotating, magnetic hot stars. This model predicts the channeling of wind plasma into a corotating magnetosphere, where -- supported against gravity by centrifugal forces -- it can steadily accumulate over time. We apply the model to the B2p star σ Ori E, demonstrating that it can simultaneously reproduce the spectroscopic, photometric and magnetic variations exhibited by the star.

  6. Archival Legacy Investigations of Circumstellar Environments (ALICE): Statistical assessment of point source detections

    Science.gov (United States)

    Choquet, Élodie; Pueyo, Laurent; Soummer, Rémi; Perrin, Marshall D.; Hagan, J. Brendan; Gofas-Salas, Elena; Rajan, Abhijith; Aguilar, Jonathan

    2015-09-01

    The ALICE program, for Archival Legacy Investigation of Circumstellar Environment, is currently conducting a virtual survey of about 400 stars, by re-analyzing the HST-NICMOS coronagraphic archive with advanced post-processing techniques. We present here the strategy that we adopted to identify detections and potential candidates for follow-up observations, and we give a preliminary overview of our detections. We present a statistical analysis conducted to evaluate the confidence level on these detection and the completeness of our candidate search.

  7. Mass loss of evolved massive stars: the circumstellar environment at high angular resolution

    International Nuclear Information System (INIS)

    Montarges, Miguel

    2014-01-01

    Mass loss of evolved stars is still largely mysterious, despite its importance as the main evolution engine for the chemical composition of the interstellar medium. For red supergiants (RSG), the triggering of the outflow and the mechanism of dust condensation remain unknown. Concerning red giant stars, we still do not know how their mass loss is able to form a bipolar planetary nebula. During my PhD thesis, I observed evolved stars with high angular resolution techniques. They allowed us to study the surface and the close environment of these stars, from where mass loss originates. With near-infrared interferometric observations, I characterized the water vapor and carbon monoxide envelope of the nearby RSG Betelgeuse. I also monitored a hot spot on its surface and analyzed the structure of its convection, as well as that of Antares (another very nearby supergiant) thanks to radiative hydrodynamical simulations. Diffraction-limited imaging techniques (near-infrared adaptive optics, ultraviolet space telescope) allowed me to observe the evolution of inhomogeneities in the circumstellar envelope of Betelgeuse and to discover a circumstellar disk around L2 Puppis, an asymptotic giant branch star. These multi-scale and multi-wavelength observations obtained at several epochs allowed us to monitor the evolution of the structures and to derive information on the dynamics of the stellar environment. With a wider stellar sample expected in the next few years, this observing program will allow a better understanding of the mass loss of evolved stars. (author)

  8. H i and CO in the circumstellar environment of the S-type star RS Cancri

    Science.gov (United States)

    Libert, Y.; Winters, J. M.; Le Bertre, T.; Gérard, E.; Matthews, L. D.

    2010-06-01

    Context. The history of mass loss during the AGB phase is key to understanding the stellar evolution and the gas and dust replenishment of the interstellar medium. The mass-loss phenomenon presents fluctuations with a wide variety of timescales and spatial scales and requires combining data from multiple tracers. Aims: We study the respective contributions of the central source and of the external medium to the complex geometry of circumstellar ejecta. Methods: This paper presents Plateau de Bure Interferometer and IRAM 30-m telescope CO rotational line observations, along with H i data obtained with the Nançay Radio Telescope for the oxygen-rich semi-regular variable RS Cnc, in order to probe its circumstellar environment on different scales. Results: We detect both the CO(1-0) and the CO(2-1) rotational lines from RS Cnc. The line profiles are composite, comprising two components of half-width ~2 km s-1 and ~8 km s-1, respectively. Whereas the narrow velocity component seems to originate in an equatorial disk in the central part of the CO envelope, the broad component reveals a bipolar structure, with a north-south velocity gradient. In addition, we obtain new H i data on the source and around it in a field of almost 1 square degree. The H i line is centered on vLSR = 7 km s-1 in agreement with CO observations. A new reduction process reveals a complex extended structure in the northwest direction, of estimated size ~18', with a position angle (~310°) opposite the direction of the stellar proper motion (~140°). We derive an H i mass of ~3 × 10-2 M_⊙ for this structure. Based on a non spherical simulation, we find that this structure is consistent with arising from the interaction of the star undergoing mass loss at an average rate of ~10-7 M⊙ yr-1 over ~2-3 × 105 years with the interstellar medium. Conclusions: Using CO and H i lines, we show that the circumstellar environment around RS Cnc includes two related but well separated regions. With CO, we

  9. Binary energy source of the HH 250 outflow and its circumstellar environment

    Science.gov (United States)

    Comerón, Fernando; Reipurth, Bo; Yen, Hsi-Wei; Connelley, Michael S.

    2018-04-01

    Aims: Herbig-Haro flows are signposts of recent major accretion and outflow episodes. We aim to determine the nature and properties of the little-known outflow source HH 250-IRS, which is embedded in the Aquila clouds. Methods: We have obtained adaptive optics-assisted L-band images with the NACO instrument on the Very Large Telescope (VLT), together with N- and Q-band imaging with VISIR also on the VLT. Using the SINFONI instrument on the VLT we carried out H- and K-band integral field spectroscopy of HH 250-IRS, complemented with spectra obtained with the SpeX instrument at the InfraRed Telescope Facility (IRTF) in the JHKL bands. Finally, the SubMillimeter Array (SMA) interferometer was used to study the circumstellar environment of HH 250-IRS at 225 and 351 GHz with CO (2-1) and CO (3-2) maps and 0.9 mm and 1.3 mm continuum images. Results: The HH 250-IRS source is resolved into a binary with 0.''53 separation, corresponding to 120 AU at the adopted distance of 225 pc. The individual components show heavily veiled spectra with weak CO absorption indicative of late-type stars. Both are Class I sources, but their spectral energy distributions between 1.5 μm and 19 μm differ markedly and suggest the existence of a large cavity around one of the components. The millimeter interferometric observations indicate that the gas mainly traces a circumbinary envelope or disk, while the dust emission is dominated by one of the circumstellar envelopes. Conclusions: HH 250-IRS is a new addition to the handful of multiple systems where the individual stellar components, the circumstellar disks and a circumbinary disk can be studied in detail, and a rare case among those systems in which a Herbig-Haro flow is present. Based on observations obtained with the VLT (Cerro Paranal, Chile) in programs 089.C-0196(A), 095.C-0488(A), and 095.C-0488(B), as well as with IRTF (Mauna Kea, Hawaii), SMA (Mauna Kea, Hawaii), and the Nordic Optical Telescope (La Palma, Canary Islands, Spain

  10. Resolving the clumpy circumstellar environment of the B[e] supergiant LHA 120-S 35

    Science.gov (United States)

    Torres, A. F.; Cidale, L. S.; Kraus, M.; Arias, M. L.; Barbá, R. H.; Maravelias, G.; Borges Fernandes, M.

    2018-05-01

    Context. B[e] supergiants are massive post-main-sequence stars, surrounded by a complex circumstellar environment where molecules and dust can survive. The shape in which the material is distributed around these objects and its dynamics as well as the mechanisms that give rise to these structures are not well understood. Aims: The aim is to deepen our knowledge of the structure and kinematics of the circumstellar disc of the B[e] supergiant LHA 120-S 35. Methods: High-resolution optical spectra were obtained in three different years. Forbidden emission lines, that contribute to trace the disc at different distances from the star, are modelled in order to determine the kinematical properties of their line-forming regions, assuming Keplerian rotation. In addition, we used low-resolution near-infrared spectra to explore the variability of molecular emission. Results: LHA 120-S 35 displays an evident spectral variability in both optical and infrared regions. The P-Cygni line profiles of H I, as well as those of Fe II and O I, suggest the presence of a strong bipolar clumped wind. We distinguish density enhancements in the P-Cygni absorption component of the first Balmer lines, which show variations in both velocity and strength. The P-Cygni profile emission component is double-peaked, indicating the presence of a rotating circumstellar disc surrounding the star. We also observe line-profile variations in the permitted and forbidden features of Fe II and O I. In the infrared, we detect variations in the intensity of the H I emission lines as well as in the emission of the CO band-heads. Moreover, we find that the profiles of each [Ca II] and [O I] emission lines contain contributions from spatially different (complete or partial) rings. Globally, we find evidence of detached multi-ring structures, revealing density variations along the disc. We identify an inner ring, with sharp edge, where [Ca II] and [O I] lines share their forming region with the CO molecular bands

  11. Advancing spaceborne tools for the characterization of planetary ionospheres and circumstellar environments

    Science.gov (United States)

    Douglas, Ewan Streets

    This work explores remote sensing of planetary atmospheres and their circumstellar surroundings. The terrestrial ionosphere is a highly variable space plasma embedded in the thermosphere. Generated by solar radiation and predominantly composed of oxygen ions at high altitudes, the ionosphere is dynamically and chemically coupled to the neutral atmosphere. Variations in ionospheric plasma density impact radio astronomy and communications. Inverting observations of 83.4 nm photons resonantly scattered by singly ionized oxygen holds promise for remotely sensing the ionospheric plasma density. This hypothesis was tested by comparing 83.4 nm limb profiles recorded by the Remote Atmospheric and Ionospheric Detection System aboard the International Space Station to a forward model driven by coincident plasma densities measured independently via ground-based incoherent scatter radar. A comparison study of two separate radar overflights with different limb profile morphologies found agreement between the forward model and measured limb profiles. A new implementation of Chapman parameter retrieval via Markov chain Monte Carlo techniques quantifies the precision of the plasma densities inferred from 83.4 nm emission profiles. This first study demonstrates the utility of 83.4 nm emission for ionospheric remote sensing. Future visible and ultraviolet spectroscopy will characterize the composition of exoplanet atmospheres; therefore, the second study advances technologies for the direct imaging and spectroscopy of exoplanets. Such spectroscopy requires the development of new technologies to separate relatively dim exoplanet light from parent star light. High-contrast observations at short wavelengths require spaceborne telescopes to circumvent atmospheric aberrations. The Planet Imaging Concept Testbed Using a Rocket Experiment (PICTURE) team designed a suborbital sounding rocket payload to demonstrate visible light high-contrast imaging with a visible nulling coronagraph

  12. MIDCOURSE SPACE EXPERIMENT VERSUS IRAS TWO-COLOR DIAGRAMS AND THE CIRCUMSTELLAR ENVELOPE-SEQUENCE OF OXYGEN-RICH LATE-TYPE STARS

    International Nuclear Information System (INIS)

    Sjouwerman, Lorant O.; Capen, Stephanie M.; Claussen, Mark J.

    2009-01-01

    We present Midcourse Space Experiment (MSX) two-color diagrams that can be used to characterize circumstellar environments of sources with good quality MSX colors in terms of IRAS color regions for oxygen-rich stars. With these diagrams, we aim to provide a new tool that can be used to study circumstellar environments and to improve detection rates for targeted surveys for circumstellar maser emission similar to the IRAS two-color diagram. This new tool is especially useful for regions in the sky where IRAS was confused, in particular in the Galactic plane and bulge region. Unfortunately, using MSX colors alone does not allow one to distinguish between carbon-rich and oxygen-rich objects. An application of this tool on 86 GHz SiO masers shows that for this type of masers an instantaneous detection rate of 60% to 80% can be achieved if target sources are selected according to MSX color (region). Our investigations may have revealed an error in the MSX point source catalog version 2.3. That is, the photometry of the 21.3 μm (MSX E filter) band for most weak 8.28 μm (or MSX A filter) band sources seems off by about a factor 2 (0.5-1 mag too bright).

  13. Hydrogenated Benzene in Circumstellar Environments: Insights into the Photostability of Super-hydrogenated PAHs

    Science.gov (United States)

    Quitián-Lara, Heidy M.; Fantuzzi, Felipe; Nascimento, Marco A. C.; Wolff, Wania; Boechat-Roberty, Heloisa M.

    2018-02-01

    Polycyclic aromatic hydrocarbons (PAHs), comprised of fused benzene (C6H6) rings, emit infrared radiation (3–12 μm) due to the vibrational transitions of the C–H bonds of the aromatic rings. The 3.3 μm aromatic band is generally accompanied by the band at 3.4 μm assigned to the vibration of aliphatic C–H bonds of compounds such as PAHs with an excess of peripheral H atoms (H n –PAHs). Herein we study the stability of fully hydrogenated benzene (or cyclohexane, C6H12) under the impact of stellar radiation in the photodissociation region (PDR) of NGC 7027. Using synchrotron radiation and time-of-flight mass spectrometry, we investigated the ionization and dissociation processes at energy ranges of UV (10–200 eV) and soft X-rays (280–310 eV). Density Functional Theory (DFT) calculations were used to determine the most stable structures and the relevant low-lying isomers of singly charged C6H12 ions. Partial Ion Yield (PIY) analysis gives evidence of the higher tendency toward dissociation of cyclohexane in comparison to benzene. However, because of the high photoabsorption cross-section of benzene at the C1s resonance edge, its photodissociation and photoionization cross-sections are enhanced, leading to a higher efficiency of dissociation of benzene in the PDR of NGC 7027. We suggest that a similar effect is experienced by PAHs in X-ray photon-rich environments, which ultimately acts as an auxiliary protection mechanism of super-hydrogenated polycyclic hydrocarbons. Finally, we propose that the single photoionization of cyclohexane could enhance the abundance of branched molecules in interstellar and circumstellar media.

  14. The circumstellar environment of evolved stars as traced by molecules and dust. The diagnostic power of Herschel

    Science.gov (United States)

    Lombaert, Robin

    2013-12-01

    Low-to-intermediate mass stars end their life on the asymptotic giant branch (AGB), an evolutionary phase in which the star sheds most of its mantle into the circumstellar environment through a stellar wind. This stellar wind expands at relatively low velocities and enriches the interstellar medium with elements newly made in the stellar interior. The physical processes controlling the gas and dust chemistry in the outflow, as well as the driving mechanism of the wind itself, are poorly understood and constitute the broader context of this thesis work. In a first chapter, we consider the thermodynamics of the high-density wind of the oxygen-rich star oh, using observations obtained with the PACS instrument onboard the Herschel Space Telescope. Being one of the most abundant molecules, water vapor can be dominant in the energy balance of the inner wind of these types of stars, but to date, its cooling contribution is poorly understood. We aim to improve the constraints on water properties by careful combination of both dust and gas radiative-transfer models. This unified treatment is needed due to the high sensitivity of water excitation to dust properties. A combination of three types of diagnostics reveals a positive radial gradient of the dust-to-gas ratio in oh. The second chapter deals with the dust chemistry of carbon-rich winds. The 30-mic dust emission feature is commonly identified as due to magnesium sulfide (MgS). However, the lack of short-wavelength measurements of the optical properties of this dust species prohibits the determination of the temperature profile of MgS, and hence its feature strength and shape, questioning whether this species is responsible for the 30-mic feature. By considering the very optically thick wind of the extreme carbon star LL Peg, this problem can be circumvented because in this case the short-wavelength optical properties are not important for the radial temperature distribution. We attribute the 30-mic feature to MgS, but

  15. Experimental and Observational Studies of Molecular Hydrogen in Interstellar and Circumstellar Environments

    Science.gov (United States)

    Hoadley, Keri

    2017-08-01

    Understanding the evolution of gas over the lifetime of protoplanetary disks provides us with important clues about how planet formation mechanisms drive the diversity of exoplanetary systems observed to date. In the first part of my thesis, I discuss how I use fluorescent emission observations of molecular hydrogen (H2) in the far-ultraviolet (far-UV) with the Hubble Space Telescope to study the warm molecular regions (a rocket experiment designed to probe the warm and cool atoms and molecules near sites of recent star formation in the local interstellar medium. I present the science goals, design, research and development components, and calibration of the CHESS instrument. I provide results on observations taken during both launches of CHESS, with detailed analysis of the epsilon Per sightline, as inferred from the flight data. I conclude by providing future works and simple estimates of the performance of an instrument like CHESS on LUVOIR to study planet-forming environments.

  16. X-RAY EMISSION FROM SUPERNOVAE IN DENSE CIRCUMSTELLAR MATTER ENVIRONMENTS: A SEARCH FOR COLLISIONLESS SHOCKS

    International Nuclear Information System (INIS)

    Ofek, E. O.; Gal-Yam, A.; Yaron, O.; Arcavi, I.; Fox, D.; Cenko, S. B.; Filippenko, A. V.; Bloom, J. S.; Sullivan, M.; Gnat, O.; Frail, D. A.; Horesh, A.; Kulkarni, S. R.; Corsi, A.; Quimby, R. M.; Gehrels, N.; Nugent, P. E.; Kasliwal, M. M.; Bildsten, L.; Poznanski, D.

    2013-01-01

    The optical light curve of some supernovae (SNe) may be powered by the outward diffusion of the energy deposited by the explosion shock (the so-called shock breakout) in optically thick (τ ∼> 30) circumstellar matter (CSM). Recently, it was shown that the radiation-mediated and radiation-dominated shock in an optically thick wind must transform into a collisionless shock and can produce hard X-rays. The X-rays are expected to peak at late times, relative to maximum visible light. Here we report on a search, using Swift/XRT and Chandra, for X-ray emission from 28 SNe that belong to classes whose progenitors are suspected to be embedded in dense CSM. Our sample includes 19 Type IIn SNe, one Type Ibn SN, and eight hydrogen-poor superluminous SNe (SLSN-I such as SN 2005ap). Two SNe (SN 2006jc and SN 2010jl) have X-ray properties that are roughly consistent with the expectation for X-rays from a collisionless shock in optically thick CSM. However, the X-ray emission from SN 2006jc can also be explained as originating in an optically thin region. Thus, we propose that the optical light curve of SN 2010jl is powered by shock breakout in CSM. We suggest that two other events (SN 2010al and SN 2011ht) were too X-ray bright during the SN maximum optical light to be explained by the shock-breakout model. We conclude that the light curves of some, but not all, SNe IIn/Ibn are powered by shock breakout in CSM. For the rest of the SNe in our sample, including all of the SLSN-I events, our X-ray limits are not deep enough and were typically obtained too early (i.e., near the SN maximum light) for definitive conclusions about their nature. Late-time X-ray observations are required in order to further test whether these SNe are indeed embedded in dense CSM. We review the conditions required for a shock breakout in a wind profile. We argue that the timescale, relative to maximum light, for the SN to peak in X-rays is a probe of the column density and the density profile above the

  17. ALMA observations of anisotropic dust mass loss in the inner circumstellar environment of the red supergiant VY Canis Majoris

    Science.gov (United States)

    O'Gorman, E.; Vlemmings, W.; Richards, A. M. S.; Baudry, A.; De Beck, E.; Decin, L.; Harper, G. M.; Humphreys, E. M.; Kervella, P.; Khouri, T.; Muller, S.

    2015-01-01

    The processes leading to dust formation and the subsequent role it plays in driving mass loss in cool evolved stars is an area of intense study. Here we present high resolution ALMA Science Verification data of the continuum emission around the highly evolved oxygen-rich red supergiant VY CMa. These data enable us to study the dust in its inner circumstellar environment at a spatial resolution of 129 mas at 321 GHz and 59 mas at 658 GHz, thus allowing us to trace dust on spatial scales down to 11 R⋆ (71 AU). Two prominent dust components are detected and resolved. The brightest dust component, C, is located 334 mas (61 R⋆) southeast of the star and has a dust mass of at least 2.5 × 10-4 M⊙. It has a dust emissivity spectral index of β = -0.1 at its peak, implying that it is optically thick at these frequencies with a cool core of Td ≲ 100 K. Interestingly, not a single molecule in the ALMA data has emission close to the peak of this massive dust clump. The other main dust component, VY, is located at the position of the star and contains a total dust mass of 4.0 × 10-5 M⊙. It also contains a weaker dust feature extending over 60 R⋆ to the north with the total component having a typical dust emissivity spectral index of β = 0.7. We find that at least 17% of the dust mass around VY CMa is located in clumps ejected within a more quiescent roughly spherical stellar wind, with a quiescent dust mass loss rate of 5 × 10-6 M⊙yr-1. The anisotropic morphology of the dust indicates a continuous, directed mass loss over a few decades, suggesting that this mass loss cannot be driven by large convection cells alone. Appendices are available in electronic form at http://www.aanda.org

  18. Fullerenes and fulleranes in circumstellar envelopes

    International Nuclear Information System (INIS)

    Zhang, Yong; Kwok, Sun; Sadjadi, SeyedAbdolreza

    2016-01-01

    Three decades of search have recently led to convincing discoveries of cosmic fullerenes. The presence of C_6_0 and C"+ _6_0 in both circumstellar and interstellar environments suggests that these molecules and their derivatives can be efficiently formed in circumstellar envelopes and survive in harsh conditions. Detailed analysis of the infrared bands from fullerenes and their connections with the local properties can provide valuable information on the physical conditions and chemical processes that occurred in the late stages of stellar evolution. The identification of C"+ _6_0 as the carrier of four diffuse interstellar bands (DIBs) suggests that fullerene- related compounds are abundant in interstellar space and are essential for resolving the DIB mystery. Experiments have revealed a high hydrogenation rate when C_6_0 is exposed to atomic hydrogen, motivating the attempt to search for cosmic fulleranes. In this paper, we present a short review of current knowledge of cosmic fullerenes and fulleranes and briefly discuss the implications on circumstellar chemistry. (paper)

  19. A multi-wavelength investigation of the radio-loud supernova PTF11qcj and its circumstellar environment

    Energy Technology Data Exchange (ETDEWEB)

    Corsi, A. [Department of Physics, The George Washington University, 725 21st St, NW, Washington, DC 20052 (United States); Ofek, E. O.; Gal-Yam, A.; Xu, D. [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel); Frail, D. A. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Kulkarni, S. R.; Horesh, A.; Carpenter, J.; Arcavi, I.; Cao, Y.; Mooley, K.; Sesar, B. [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Fox, D. B. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Kasliwal, M. M. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Sullivan, M.; Maguire, K.; Pan, Y.-C. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Cenko, S. B. [NASA Goddard Space Flight Center, Code 685, Greenbelt, MD 20771 (United States); Sternberg, A. [Max-Planck-Institut fur Astrophysik, D-85741 Garching (Germany); Bersier, D., E-mail: corsi@gwu.edu [Astrophysics Research Institute, Liverpool John Moores University, Liverpool (United Kingdom); and others

    2014-02-10

    We present the discovery, classification, and extensive panchromatic (from radio to X-ray) follow-up observations of PTF11qcj, a supernova (SN) discovered by the Palomar Transient Factory (PTF). Our observations with the Karl G. Jansky Very Large Array show that this event is radio-loud: PTF11qcj reached a radio peak luminosity comparable to that of the famous gamma-ray-burst-associated SN 1998bw (L {sub 5} {sub GHz} ≈ 10{sup 29} erg s{sup –1} Hz{sup –1}). PTF11qcj is also detected in X-rays with the Chandra Observatory, and in the infrared band with Spitzer. Our multi-wavelength analysis probes the SN interaction with circumstellar material. The radio observations suggest a progenitor mass-loss rate of ∼10{sup –4} M {sub ☉} yr{sup –1} × (v{sub w} /1000 km s{sup –1}), and a velocity of ≈0.3-0.5 c for the fastest moving ejecta (at ≈10 days after explosion). However, these estimates are derived assuming the simplest model of SN ejecta interacting with a smooth circumstellar wind, and do not account for possible inhomogeneities in the medium and asphericity of the explosion. The radio data show deviations from such a simple model, as well as a late-time re-brightening. The X-ray flux from PTF11qcj is compatible with the high-frequency extrapolation of the radio synchrotron emission (within the large uncertainties). A light echo from pre-existing dust is in agreement with our infrared data. Our pre-explosion data from the PTF suggest that a precursor eruption of absolute magnitude M{sub r} ≈ –13 mag may have occurred ≈2.5 yr prior to the SN explosion. Overall, PTF11qcj fits the expectations from the explosion of a Wolf-Rayet star. Precursor eruptions may be a feature characterizing the final pre-explosion evolution of such stars.

  20. CONFIRMATION OF CIRCUMSTELLAR PHOSPHINE

    Energy Technology Data Exchange (ETDEWEB)

    Agúndez, M.; Cernicharo, J. [Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, E-28049 Cantoblanco (Spain); Decin, L. [Sterrenkundig Instituut Anton Pannekoek, University of Amsterdam, Science Park 904, NL-1098 Amsterdam (Netherlands); Encrenaz, P. [LERMA, Observatoire de Paris, 61 Av. de l' Observatoire, F-75014 Paris (France); Teyssier, D. [European Space Astronomy Centre, Urb. Villafranca del Castillo, P.O. Box 50727, E-28080 Madrid (Spain)

    2014-08-01

    Phosphine (PH{sub 3}) was tentatively identified a few years ago in the carbon star envelopes IRC +10216 and CRL 2688 from observations of an emission line at 266.9 GHz attributable to the J = 1-0 rotational transition. We report the detection of the J = 2-1 rotational transition of PH{sub 3} in IRC +10216 using the HIFI instrument on board Herschel, which definitively confirms the identification of PH{sub 3}. Radiative transfer calculations indicate that infrared pumping in excited vibrational states plays an important role in the excitation of PH{sub 3} in the envelope of IRC +10216, and that the observed lines are consistent with phosphine being formed anywhere between the star and 100 R {sub *} from the star, with an abundance of 10{sup –8} relative to H{sub 2}. The detection of PH{sub 3} challenges chemical models, none of which offer a satisfactory formation scenario. Although PH{sub 3} holds just 2% of the total available phosphorus in IRC +10216, it is, together with HCP, one of the major gas phase carriers of phosphorus in the inner circumstellar layers, suggesting that it could also be an important phosphorus species in other astronomical environments. This is the first unambiguous detection of PH{sub 3} outside the solar system, and is a further step toward a better understanding of the chemistry of phosphorus in space.

  1. An Interferometric Study of the Post-AGB Binary 89 Herculis. 1: Spatially Resolving the Continuum Circumstellar Environment at Optical and Near-IR Wavelengths with the VLTI, NPOI, IOTA, PTI, and the CHARA Array

    Science.gov (United States)

    2013-01-01

    Herculis I. Spatially resolving the continuum circumstellar environment at optical and near-IR wavelengths with the VLTI, NPOI, IOTA , PTI, and the CHARA...public release; distribution unlimited 13. SUPPLEMENTARY NOTES A&A 559, A111 (2013) 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION...Array ( IOTA ) and the Center for High Angular Resolution Astronomy (CHARA) Array, covering 0.5 to 2.2 μm and with baselines from 15 to 278 m. Here we

  2. The Spectroscopic Evolution of the Symbiotic-like Recurrent Nova V407 Cygni During Its 2010 Outburst. 2. The Circumstellar Environment and the Aftermath

    Science.gov (United States)

    Shore, S. N.; Wahlgren, G. M.; Augusteijn, T.; Liimets, T.; Koubsky, P.; Slechta, M.; Votruba, V.

    2011-01-01

    The nova outburst of V407 Cyg in 2010 Mar. 10 was the first observed for this star but its close resemblance to the well known symbiotic-like recurrent nova RS Oph suggests that it is also a member of this rare type of Galactic novae. The nova was the first detected at gamma-ray energies and is the first known nova explosion for this system. The extensive multiwavelength coverage of this outburst makes it an ideal comparison with the few other outbursts known for similar systems. We extend our previous analysis of the Mira and the expanding shock from the explosion to detail the time development of the photoionized Mira wind, circumstellar medium, and shocked circumstellar environment to derive their physical parameters and how they relate to large scale structure of the environment, extending the previous coverage to more than 500 days after outburst. We use optical spectra obtained at high resolution with the Nordic Optical Telescope (NOT) (R approx. =.45000 to 65000) and medium resolution Ondrejov Observatory (R approx. = 12000) data and compare the line variations with publicly available archival measurements at 30 GHz OVNR and at X-rays with Swift during the first four months of the outburst, through the end of the epoch of strong XR emission. We use nebular diagnostics and high resolution profile variations to derive the densities and locations of the extended emission. We find that the higher the ionization and/or the higher the excitation energy, the more closely the profiles resemble the He II/Ca V-type high velocity shock profile discussed in Paper I. This also accounts for the comparative development of the [N II] and [O III] isoelectronic transitions: the [O III] 4363A profile does not show the low velocity peaks while the excited [N II] 5754A does. If nitrogen is mainly N(+3) or higher in the shock, the upper state of the [N II] nebular lines will contribute but if the oxygen is O(+2) then this line is formed by recombination, masking the nebular

  3. Simple Analytic Collisional Rates for non-LTE Vibrational Populations in Astrophysical Environments: the Cases of Circumstellar SiO Masers and Shocked H2

    Science.gov (United States)

    Bieniek, Ronald

    2008-05-01

    Rates for collisionally induced transitions between molecular vibrational levels are important in modeling a variety of non-LTE processes in astrophysical environments. Two examples are SiO masering in circumstellar envelopes in certain late-type stars [1] and the vibrational populations of molecular hydrogen in shocked interstellar medium [cf 2]. A simple exponential-potential model of molecular collisions leads to a two-parameter analytic expression for state-to-state and thermally averaged rates for collisionally induced vibrational-translational (VT) transitions in diatomic molecules [3,4]. The thermally averaged rates predicted by this formula have been shown to be in excellent numerical agreement with absolute experimental and quantum mechanical rates over large temperature ranges and initial vibrational excitation levels in a variety of species, e.g., OH, O2, N2 [3] and even for the rate of H2(v=1)+H2, which changes by five orders of magnitude in the temperature range 50-2000 K [4]. Analogous analytic rates will be reported for vibrational transitions in SiO due to collisions with H2 and compared to the numerical fit of quantum-mechanical rates calculated by Bieniek and Green [5]. [1] Palov, A.P., Gray, M.D., Field, D., & Balint-Kurti, G.G. 2006, ApJ, 639, 204. [2] Flower, D. 2007, Molecular Collisions in the Interstellar Medium (Cambridge: Cambridge Univ. Press) [3] Bieniek, R.J. & Lipson, S.J. 1996, Chem. Phys. Lett. 263, 276. [4] Bieniek, R.J. 2006, Proc. NASA LAW (Lab. Astrophys. Workshop) 2006, 299; http://www.physics.unlv.edu/labastro/nasalaw2006proceedings.pdf. [5] Bieniek, R.J., & Green, S. 1983, ApJ, 265, L29 and 1983, ApJ, 270, L101.

  4. An interferometric study of the post-AGB binary 89 Herculis. I. Spatially resolving the continuum circumstellar environment at optical and near-IR wavelengths with the VLTI, NPOI, IOTA, PTI, and the CHARA Array

    Science.gov (United States)

    Hillen, M.; Verhoelst, T.; Van Winckel, H.; Chesneau, O.; Hummel, C. A.; Monnier, J. D.; Farrington, C.; Tycner, C.; Mourard, D.; ten Brummelaar, T.; Banerjee, D. P. K.; Zavala, R. T.

    2013-11-01

    Context. Binary post-asymptotic giant branch (post-AGB) stars are interesting laboratories to study both the evolution of binaries as well as the structure of circumstellar disks. Aims: A multiwavelength high angular resolution study of the prototypical object 89 Herculis is performed with the aim of identifying and locating the different emission components seen in the spectral energy distribution. Methods: A large interferometric data set, collected over the past decade and covering optical and near-infrared wavelengths, is analyzed in combination with the spectral energy distribution and flux-calibrated optical spectra. In this first paper only simple geometric models are applied to fit the interferometric data. Combining the interferometric constraints with the photometry and the optical spectra, we re-assess the energy budget of the post-AGB star and its circumstellar environment. Results: We report the first (direct) detection of a large (35-40%) optical circumstellar flux contribution and spatially resolve its emission region. Given this large amount of reprocessed and/or redistributed optical light, the fitted size of the emission region is rather compact and fits with(in) the inner rim of the circumbinary dust disk. This rim dominates our K band data through thermal emission and is rather compact, emitting significantly already at a radius of twice the orbital separation. We interpret the circumstellar optical flux as due to a scattering process, with the scatterers located in the extremely puffed-up inner rim of the disk and possibly also in a bipolar outflow seen pole-on. A non-local thermodynamic equilibrium gaseous origin in an inner disk cannot be excluded but is considered highly unlikely. Conclusions: This direct detection of a significant amount of circumbinary light at optical wavelengths poses several significant questions regarding our understanding of both post-AGB binaries and the physics in their circumbinary disks. Although the

  5. Laboratory Studies Of Circumstellar Carbonaceous Grain Formation

    Science.gov (United States)

    Contreras, Cesar; Sciamma-O'Brien, Ella; Salama, Farid

    2014-06-01

    The study of the formation processes of dust is essential to understand the budget of extraterrestrial organic molecules. Although dust with all its components plays an important role in the evolution of interstellar (IS) chemistry and in the formation of organic molecules, little is known on the formation processes of carbonaceous dust. We report the progress that was recently achieved in this domain using NASA Ames’ COSmIC facility (Contreras & Salama 2013, ApJS, 208, 6). PAHs are important chemical building blocks of IS dust. They are detected in IDPs and in meteoritic samples. Additionally, observational, laboratory, and theoretical studies have shown that PAHs are an important, ubiquitous component of the ISM. The formation of PAHs from smaller molecules has not been extensively studied. Therefore, we have performed laboratory experiments to study the dynamic processes of carbon grain formation, starting from the smallest hydrocarbon molecules into the formation of larger PAH and further into nanograins. Studies of IS dust analogs formed from a variety of PAH and hydrocarbon precursors as well as species that include the atoms O, N, and S, have recently been performed in our laboratory using the COSmIC facility to provide conditions that simulate IS and circumstellar environments. The species formed in the COSmiC chamber through a pulsed discharge nozzle plasma source are detected and characterized with a cavity ringdown spectrometer coupled to a time-of-flight mass spectrometer, thus providing both spectroscopic and ion mass information in-situ. Analysis of solid soot particles was also conducted using scanning electron microscopy at the UCSC/NASA Ames’ MACS facility. The SEM analysis of the deposition of soot from methane and acetylene precursors seeded in argon plasmas provide examples on the types of nanoparticles and micrograins that are produced in these gas mixtures under our experimental conditions. From these measurements, we derive information on

  6. Information literacy experiencies inside virtual learning environments

    Directory of Open Access Journals (Sweden)

    Patricia Hernández Salazar

    2016-03-01

    Full Text Available Objective. Suggest the use of virtual learning environments as an Information Literacy (IL alternative. Method. Analysis of the main elements of web sites. To achieve this purpose the article includes the relationship between IL and the learning virtual environment (by defining both phrases; phases to create virtual IL programs; processes to elaborate didactic media; the applications that may support this plan; and the description of eleven examples of learning virtual environments IL experiences from four countries (Mexico, United States of America, Spain and United Kingdom these examples fulfill the conditions expressed. Results. We obtained four comparative tables examining five elements of each experience: objectives; target community; institution; country; and platform used. Conclusions. Any IL proposal should have a clear definition; IL experiences have to follow a didactic systematic process; described experiences are based on IL definition; the experiences analyzed are similar; virtual learning environments can be used as alternatives of IL.

  7. Specimen environments in thermal neutron scattering experiments

    International Nuclear Information System (INIS)

    Cebula, D.J.

    1980-11-01

    This report is an attempt to collect into one place outline information concerning the techniques used and basic design of sample environment apparatus employed in neutron scattering experiments. Preliminary recommendations for the specimen environment programme of the SNS are presented. The general conclusion reached is that effort should be devoted towards improving reliability and efficiency of operation of specimen environment apparatus and developing systems which are robust and easy to use, rather than achieving performance at the limits of technology. (author)

  8. Organic compounds in circumstellar and interstellar environments.

    Science.gov (United States)

    Kwok, Sun

    2015-06-01

    Recent research has discovered that complex organic matter is prevalent throughout the Universe. In the Solar System, it is found in meteorites, comets, interplanetary dust particles, and planetary satellites. Spectroscopic signatures of organics with aromatic/aliphatic structures are also found in stellar ejecta, diffuse interstellar medium, and external galaxies. From space infrared spectroscopic observations, we have found that complex organics can be synthesized in the late stages of stellar evolution. Shortly after the nuclear synthesis of the element carbon, organic gas-phase molecules are formed in the stellar winds, which later condense into solid organic particles. This organic synthesis occurs over very short time scales of about a thousand years. In order to determine the chemical structures of these stellar organics, comparisons are made with particles produced in the laboratory. Using the technique of chemical vapor deposition, artificial organic particles have been created by injecting energy into gas-phase hydrocarbon molecules. These comparisons led us to believe that the stellar organics are best described as amorphous carbonaceous nanoparticles with mixed aromatic and aliphatic components. The chemical structures of the stellar organics show strong similarity to the insoluble organic matter found in meteorites. Isotopic analysis of meteorites and interplanetary dust collected in the upper atmospheres have revealed the presence of pre-solar grains similar to those formed in old stars. This provides a direct link between star dust and the Solar System and raises the possibility that the early Solar System was chemically enriched by stellar ejecta with the potential of influencing the origin of life on Earth.

  9. CIRCUMSTELLAR SHELLS IN ABSORPTION IN TYPE Ia SUPERNOVAE

    International Nuclear Information System (INIS)

    Borkowski, Kazimierz J.; Blondin, John M.; Reynolds, Stephen P.

    2009-01-01

    Progenitors of Type Ia supernovae (SNe) have been predicted to modify their ambient circumstellar (CSM) and interstellar environments through the action of their powerful winds. While there is X-ray and optical evidence for circumstellar interaction in several remnants of Type Ia SNe, widespread evidence for such interaction in Type Ia SNe themselves has been lacking. We consider prospects for the detection of CSM shells that have been predicted to be common around Type Ia SNe. Such shells are most easily detected in Na I absorption lines. Variable (declining) absorption is expected to occur soon after the explosion, primarily during the SN rise time, for shells located within ∼1-10 pc of a SN. The distance of the shell from the SN can be determined by measuring the timescale for line variability.

  10. The composition of circumstellar and interstellar dust

    NARCIS (Netherlands)

    Tielens, AGGM; Woodward, CE; Biscay, MD; Shull, JM

    2001-01-01

    A large number of solid dust components have been identified through analysis of stardust recovered from meteorites, and analysis of IR observations of circumstellar shells and the interstellar medium. These include graphite, hydrogenated amorphous carbon, diamond, PAHs, silicon-, iron-, and

  11. Tracing Planets in Circumstellar Discs

    Directory of Open Access Journals (Sweden)

    Uribe Ana L.

    2013-04-01

    Full Text Available Planets are assumed to form in circumstellar discs around young stellar objects. The additional gravitational potential of a planet perturbs the disc and leads to characteristic structures, i.e. spiral waves and gaps, in the disc density profile. We perform a large-scale parameter study on the observability of these planet-induced structures in circumstellar discs in the (submm wavelength range for the Atacama Large (SubMillimeter Array (ALMA. On the basis of hydrodynamical and magneto-hydrodynamical simulations of star-disc-planet models we calculate the disc temperature structure and (submm images of these systems. These are used to derive simulated ALMA maps. Because appropriate objects are frequent in the Taurus-Auriga region, we focus on a distance of 140 pc and a declination of ≈ 20°. The explored range of star-disc-planet configurations consists of six hydrodynamical simulations (including magnetic fields and different planet masses, nine disc sizes with outer radii ranging from 9 AU to 225 AU, 15 total disc masses in the range between 2.67·10-7 M⊙ and 4.10·10-2 M⊙, six different central stars and two different grain size distributions, resulting in 10 000 disc models. At almost all scales and in particular down to a scale of a few AU, ALMA is able to trace disc structures induced by planet-disc interaction or the influence of magnetic fields in the wavelength range between 0.4...2.0 mm. In most cases, the optimum angular resolution is limited by the sensitivity of ALMA. However, within the range of typical masses of protoplane tary discs (0.1 M⊙...0.001 M⊙ the disc mass has a minor impact on the observability. At the distance of 140 pc it is possible to resolve discs down to 2.67·10-6 M⊙ and trace gaps in discs with 2.67·10-4 M⊙ with a signal-to-noise ratio greater than three. In general, it is more likely to trace planet-induced gaps in magneto-hydrodynamical disc models, because gaps are wider in the presence of

  12. Controlled environment experiments in pollution studies

    Energy Technology Data Exchange (ETDEWEB)

    Zeitzschel, B

    1978-12-01

    In the last decade society has become aware of the increasing negative effects of human waste products introduced to the oceans. There is proof evidence, at least for some areas of the world ocean, that the marine environment is seriously in danger. The scientific community is very concerned, arguing that there is an urgent need for basic research in this field because too little is known on the harzardous effects of man-made pollutants on the structure and functioning of marine ecosystems. There are two wanys to perform experiments under conrolled environment conditions: (1) in the laboratory; (2) in in-situ experiments with enclosures. Most laboratory experiments are designed to study the influence and the tolerance spectrum of specific pollutants, e.g. copper or DDT, on any specific organism, e.g. a mussel or a fish. In these experiments it is fairly difficult to simulate natural conditions. The concentrations of the pollutants are generally fairly high, often several orders of magnitude higher than in the ocean. It is questionable if the results from these experiments can be extrapolated to nature. In the second approach (enclosures of various sizes in-situ or in landbased facilities), fibre-glass containers and plastic bags have been used successfully in the last years, e.g. in the UK, USA, Canada, France, and W. Germany. The main goal of these experiments is to study the long-term effect of low-level perturbations on natural populations of the pelagic or benthic ecosystem. Examples of recent results are discussed in detail. 33 references.

  13. Improving the Urban Environment experiences in Peshawar

    International Nuclear Information System (INIS)

    Malik, M.

    2001-01-01

    This paper summarizes the experiences of the Pak-German Urban Industrial Environment Protection (UIEP) Program that was implemented in Peshawar, North-West Frontier Province (NWFP), Pakistan from May 1996 to October 2000. Under the UIEP, which had the goal of improving the environmental situation in NWFP, pilot-projects focusing on air pollution control from vehicular emissions and brick kilns, improvement of solid waste collection and disposal of outdated pesticides were implemented. In addition, a number of studies and surveys focusing on hospital waste management, pressure horns, ambient noise level, fuel and oil adulteration and ambient air quality were undertaken. The paper highlights the strategies used for the implementation of the pilot-projects and presents useful data concerning the urban environment of NWFP. (author)

  14. Personal Pervasive Environments: Practice and Experience

    Directory of Open Access Journals (Sweden)

    Enrique Soriano

    2012-05-01

    Full Text Available In this paper we present our experience designing and developing two different systems to enable personal pervasive computing environments, Plan B and the Octopus. These systems were fully implemented and have been used on a daily basis for years. Both are based on synthetic (virtual file system interfaces and provide mechanisms to adapt to changes in the context and reconfigure the system to support pervasive applications. We also present the main differences between them, focusing on architectural and reconfiguration aspects. Finally, we analyze the pitfalls and successes of both systems and review the lessons we learned while designing, developing, and using them.

  15. Studies of Young, Star-forming Circumstellar Disks

    Science.gov (United States)

    Bae, Jaehan

    2017-08-01

    . When a planet forms in a disk, the gravitational interaction between the planet and disk can create structures, such as spiral arms and gaps. In Chapter 5, I compared the disk structures formed by planetary companions in numerical simulations with the observed structures in the disk surrounding an 8 Myr-old Herbig Ae star SAO 206462. Based on the experiments, I made predictions for the mass and position of a currently unrevealed planet, which can help guide future observations to search for more conclusive evidence for the existence of a planetary companion in the system. In Chapter 6, I showed for the first time in global simulation domains that spiral waves, driven for instance by planets or gravitational instability, can be unstable due to resonant interactions with inertial modes, breaking into turbulence. In Chapter 7, I showed that the spiral wave instability operates on the waves launched by planets and that the resulting turbulence can significantly stir up solid particles from the disk midplane. The stirring of solid particles can have influences on the observation appearance of the parent disk and on the subsequent assembly of planetary bodies in the disk. Finally, in Chapter 8, I investigated the dispersal of circumstellar disks via photoevaporative winds, finding that the photoevaporative loss alone, coupled with a range of initial angular momenta of protostellar clouds, can explain the observed decline of the disk frequency with increasing age. The findings and future possibilities are summarized in Chapter 9.

  16. On circumstellar molecules in the Pleiades.

    Science.gov (United States)

    Hobbs, L. M.

    1972-01-01

    Consideration of both old and new observations of the interstellar 4232-A line of CH(+) for the brightest members of the Pleiades. These observations suggest that the molecules are circumstellar in some sense, perhaps resembling in this respect the micron-sized grains inferred to be present in this region.

  17. A surgical virtual environment for navigating experience.

    NARCIS (Netherlands)

    Luursema, J.M.; Kommers, Petrus A.M.

    2004-01-01

    A computer generated pre-surgical planning and teaching environment is proposed for training and evaluating novice surgeons. Although this environment is generic and can be put into practice in any medical specialisation where such 3D imaging techniques are in use, in this project we specifically

  18. The Danish experience of strategic environment assesment

    DEFF Research Database (Denmark)

    Kørnøv, Lone

    2004-01-01

    The article recounts a number of examples of the Danish experience with Strategic Environmental Assessment (SEA).......The article recounts a number of examples of the Danish experience with Strategic Environmental Assessment (SEA)....

  19. LASL experience in decontamination of the environment

    International Nuclear Information System (INIS)

    Ahlquist, A.J.

    1979-01-01

    Since 1972 the Los Alamos Scientific Laboratory (LASL) has been actively involved in land area surveys for radioactive contamination and has gained considerable experience in cleanup of lands considered to have unacceptable levels of radioactive contamination. Experience and means of arriving at recommendations for decontamination at levels as low as reasonably achievable

  20. LASL experience in decontamination of the environment

    International Nuclear Information System (INIS)

    Ahlquist, A.J.

    1979-01-01

    Since 1972 the Los Alamos Scientific Laboratory (LASL) has been actively involved in land area surveys for radioactive contamination and has gained considerable experience in cleanup of lands considered to have unacceptable levels of radioactive contamination. This paper describes our experience and means of arriving at recommendations for ALARA

  1. Millimeter wave studies of circumstellar chemistry

    Science.gov (United States)

    Tenenbaum, Emily Dale

    2010-06-01

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

  2. Evidence for circumstellar obscuration of OB stars

    International Nuclear Information System (INIS)

    Bohannan, B.

    1975-01-01

    Reddish found a strong increase of color excess with increasing stellar luminosity: here referred to as the Reddish Effect: in ten young galactic clusters and associations. New photometric and spectroscopic observations drawn from the literature are combined with data used by Reddish to reconsider the color excess versus intrinsic magnitude diagrams of the same ten stellar groups. The reality of the Effect is questioned in all but one of the systems; this was accomplished by identifying possible foreground stars and by recognizing some of the brightest stars as supergiants, then applying correct intrinsic color indices. After careful reanalysis, the one stellar group to retain an indication of the Reddish Effect is Cygnus OB2. No correlation of reddening with luminosity was found for five additional very young stellar groups in the southern hemisphere; these groups should exhibit the Effect if it is a natural consequence of stellar evolution. Reddish ascribed the correlation to massive circumstellar remnants of material from which the stars formed. However, a peculiar dispersion in color excess could also be attributed to patchy dust within the stellar group. In several stellar systems previously identified as displaying the Reddish Effect, a correlation of observed color excess with dust and gas concentrations is noted on Palomar Sky Survey prints. If present, circumstellar dust clouds should []anifest their existence in modes other than a correlation of color excess with luminosity. The following possibilities are considered and all show negative results: correlation of color excess with spectral type; correlation of reddening slope E/subU//sub -//subB//E/subB//sub -//subV/ with spectral type; observable infrared excess. The preceding astrophysical arguments strongly imply that circumstellar dust remnants from stellar formation do not remain around stars during their main-sequence lifetimes. (auth)

  3. Study at radio wavelengths of circumstellar envelopes around red giants

    International Nuclear Information System (INIS)

    Do Thi Hoai

    2015-01-01

    The thesis studies mass losing AGB stars and their circumstellar environments, with focus on the development of stellar outflows and their interaction with the surrounding medium. It uses emission from two tracers: carbon monoxide (CO), through its rotational lines in the millimeter range, probes the inner regions of the circumstellar shells out to photodissociation distances, while atomic hydrogen (HI, 21 cm) is better suited to the study of the external regions. The high spectral and spatial resolutions achieved in radio observations allow for a detailed exploration of the kinematics of the relatively slow outflows of red giants. After having introduced the subject, I discuss the case of an S-type star (RS Cnc) that has been observed in CO with the IRAM telescopes, as well as in HI with the VLA, concentrating on the modelling of the spatially resolved CO line profiles and illustrating the complementarity between HI and CO. Results of the CO modelling of other AGB stars observed at IRAM (EP Aqr, XHer and RXBoo) and of a post-AGB star observed with ALMA, the Red Rectangle, are also presented. The formation of the HI line profile in various cases of mass losing AGB stars, in particular YCVn for which a model is presented, is studied next, exploring several effects that might explain the lack of detected emission from stars with high mass loss rates. Similarities between the bipolar outflows of the AGB stars that have been studied, all having mass loss rates in the region of 10"-"7 solar masses per year and displaying nearly spherical morphologies are discussed together with the information on the gas temperature obtained from the simultaneous observation of two CO lines. (author)

  4. Changing the food environment: the French experience.

    Science.gov (United States)

    Chauliac, Michel; Hercberg, Serge

    2012-07-01

    The French National Nutrition and Health Program was launched in 2001. To achieve its objectives, 2 main preventive strategies were identified: 1) provide information and education to help individuals make healthy food and physical activity choices; and 2) improve the food and physical environment so that making healthy choices is easier. School regulations have been established to improve the nutritional quality of meals served to children and adolescents, and vending machines have been banned. Since 2007, companies in France's food industry have had the option of signing the national government's "Charte d'engagement volontaire de progrès nutritionnel" (charter of commitments to nutritional improvements) which aims to benefit all consumers. A standard reference document, developed by public authorities as the basis for decisions made by a committee of experts in the food industry, aims to validate the voluntary commitments made by companies to improve the nutrient content of the foods they produce. There is strict follow-up. A Food Quality Observatory was created in 2009 to monitor the nutrient quality of the food supply in France. Various results show the positive impact of these actions.

  5. Utilizing Urban Environments for Effective Field Experiences

    Science.gov (United States)

    MacAvoy, S. E.; Knee, K.

    2014-12-01

    Research surveys suggest that students are demanding more applied field experiences from their undergraduate environmental science programs. For geoscience educators at liberal arts colleges without field camps, university vehicles, or even geology departments, getting students into the field is especially rewarding - and especially challenging. Here, we present strategies that we have used in courses ranging from introductory environmental science for non-majors, to upper level environmental methods and geology classes. Urban locations provide an opportunity for a different type of local "field-work" than would otherwise be available. In the upper-level undergraduate Environmental Methods class, we relied on a National Park area located a 10-minute walk from campus for most field exercises. Activities included soil analysis, measuring stream flow and water quality parameters, dendrochronology, and aquatic microbe metabolism. In the non-majors class, we make use of our urban location to contrast water quality in parks and highly channelized urban streams. Here we share detailed lesson plans and budgets for field activities that can be completed during a class period of 2.5 hours with a $75 course fee, show how these activities help students gain quantitative competency, and provide student feedback about the classes and activities.

  6. Composite grains: Application to circumstellar dust

    Directory of Open Access Journals (Sweden)

    D. B. Vaidya

    2011-09-01

    Full Text Available Using the discrete dipole approximation (DDA we calculate the absorption efficiency of the composite grain, made up of a host silicate spheroid and inclusions of graphite, in the spectral region 5.0-25.0μm. We study the absorption as a function of the voulume fraction of the inclusions. In particular, we study the variation in the 10.0μm and 18.0μm emission features with the volume fraction of the inclusions. Using the extinction efficiencies, of the composite grains we calculate the infrared fluxes at several dust temperatures and compare the model curves with the observed infrared emission curves (IRAS-LRS, obtained for circumstellar dust shells around oxygen rich M-type stars.

  7. Indian deepsea environment experiment (index): Achievements and applications

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, R.

    impact experiment. Evaluation of impact of simulated disturbance in the benthic environment shows vertical mixing of sediment, lateral distribution of particles, changes in geochemical and biochemical conditions as well as reduction in biomass...

  8. Optimising the Blended Learning Environment: The Arab Open University Experience

    Science.gov (United States)

    Hamdi, Tahrir; Abu Qudais, Mohammed

    2018-01-01

    This paper will offer some insights into possible ways to optimise the blended learning environment based on experience with this modality of teaching at Arab Open University/Jordan branch and also by reflecting upon the results of several meta-analytical studies, which have shown blended learning environments to be more effective than their face…

  9. Practical Applications and Experiences in K-20 Blended Learning Environments

    Science.gov (United States)

    Kyei-Blankson, Lydia, Ed.; Ntuli, Esther, Ed.

    2014-01-01

    Learning environments continue to change considerably and is no longer confined to the face-to-face classroom setting. As learning options have evolved, educators must adopt a variety of pedagogical strategies and innovative technologies to enable learning. "Practical Applications and Experiences in K-20 Blended Learning Environments"…

  10. Web experience effects in a virtual shopping interaction environment

    NARCIS (Netherlands)

    Lorenzo-Romero, C.; Constantinides, Efthymios; Gomez-Borja, M.A.; Lin, A.; Foster, J.; Scifleet, P.

    2013-01-01

    The objective of this chapter is to contextualize the concepts of web atmospherics and web experience in the particular case of a shopping situation in the Internet environment. Based on a broader concept of user experience, the chapter identifies the main influencers of consumer behaviour in the

  11. Introduction of sample environment equipment for neutron scattering experiments

    International Nuclear Information System (INIS)

    Shimojo, Yutaka; Ihata, Yoshiaki; Kaneko, Koji; Takeda, Masayasu

    2013-02-01

    Neutron scattering experiments have been frequently performed under variety of sample conditions, such as various temperatures, pressures, magnetic fields and stresses, and those complex conditions to fully utilize superior properties of neutron. To this aim, a number of sample environment equipment, refrigerators, furnaces, pressure cells, superconducting magnets are equipped in JRR-3 to be used for experiments. In this document, all available sample environment equipment in both JRR-3 reactor and guide halls are summarized. We hope this document would help neutron scattering users to perform effective and excellent experiments. (author)

  12. Constraints on Circumstellar Dust Grain Sizes from High Spatial Resolution Observations in the Thermal Infrared

    Science.gov (United States)

    Bloemhof, E. E.; Danen, R. M.; Gwinn, C. R.

    1996-01-01

    We describe how high spatial resolution imaging of circumstellar dust at a wavelength of about 10 micron, combined with knowledge of the source spectral energy distribution, can yield useful information about the sizes of the individual dust grains responsible for the infrared emission. Much can be learned even when only upper limits to source size are available. In parallel with high-resolution single-telescope imaging that may resolve the more extended mid-infrared sources, we plan to apply these less direct techniques to interpretation of future observations from two-element optical interferometers, where quite general arguments may be made despite only crude imaging capability. Results to date indicate a tendency for circumstellar grain sizes to be rather large compared to the Mathis-Rumpl-Nordsieck size distribution traditionally thought to characterize dust in the general interstellar medium. This may mean that processing of grains after their initial formation and ejection from circumstellar atmospheres adjusts their size distribution to the ISM curve; further mid-infrared observations of grains in various environments would help to confirm this conjecture.

  13. CIRCUMSTELLAR DEBRIS DISKS: DIAGNOSING THE UNSEEN PERTURBER

    Energy Technology Data Exchange (ETDEWEB)

    Nesvold, Erika R. [Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Rd., Washington, DC 20015 (United States); Naoz, Smadar; Vican, Laura [Department of Physics and Astronomy, UCLA, 475 Portola Plaza, Los Angeles, CA 90095 (United States); Farr, Will M. [School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT (United Kingdom)

    2016-07-20

    The first indication of the presence of a circumstellar debris disk is usually the detection of excess infrared emission from the population of small dust grains orbiting the star. This dust is short-lived, requiring continual replenishment, and indicating that the disk must be excited by an unseen perturber. Previous theoretical studies have demonstrated that an eccentric planet orbiting interior to the disk will stir the larger bodies in the belt and produce dust via interparticle collisions. However, motivated by recent observations, we explore another possible mechanism for heating a debris disk: a stellar-mass perturber orbiting exterior to and inclined to the disk and exciting the disk particles’ eccentricities and inclinations via the Kozai–Lidov mechanism. We explore the consequences of an exterior perturber on the evolution of a debris disk using secular analysis and collisional N -body simulations. We demonstrate that a Kozai–Lidov excited disk can generate a dust disk via collisions and we compare the results of the Kozai–Lidov excited disk with a simulated disk perturbed by an interior eccentric planet. Finally, we propose two observational tests of a dust disk that can distinguish whether the dust was produced by an exterior brown dwarf or stellar companion or an interior eccentric planet.

  14. CIRCUMSTELLAR SHELL FORMATION IN SYMBIOTIC RECURRENT NOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Kevin; Bildsten, Lars [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106 (United States)

    2012-12-20

    We present models of spherically symmetric recurrent nova shells interacting with circumstellar material (CSM) in a symbiotic system composed of a red giant (RG) expelling a wind and a white dwarf accreting from this material. Recurrent nova eruptions periodically eject material at high velocities ({approx}> 10{sup 3} km s{sup -1}) into the RG wind profile, creating a decelerating shock wave as CSM is swept up. High CSM densities cause the shocked wind and ejecta to have very short cooling times of days to weeks. Thus, the late-time evolution of the shell is determined by momentum conservation instead of energy conservation. We compute and show evolutionary tracks of shell deceleration, as well as post-shock structure. After sweeping up all the RG wind, the shell coasts at a velocity {approx}100 km s{sup -1}, depending on system parameters. These velocities are similar to those measured in blueshifted CSM from the symbiotic nova RS Oph, as well as a few Type Ia supernovae that show evidence of CSM, such as 2006X, 2007le, and PTF 11kx. Supernovae occurring in such systems may not show CSM interaction until the inner nova shell gets hit by the supernova ejecta, days to months after the explosion.

  15. Circumstellar disks around binary stars in Taurus

    International Nuclear Information System (INIS)

    Akeson, R. L.; Jensen, E. L. N.

    2014-01-01

    We have conducted a survey of 17 wide (>100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10 –4 M ☉ . We compare the properties of our sample to the population of known disks in Taurus and find that the disks from this binary sample match the scaling between stellar mass and millimeter flux of F mm ∝M ∗ 1.5--2.0 to within the scatter found in previous studies. We also compare the properties of the primaries to those of the secondaries and find that the secondary/primary stellar and disk mass ratios are not correlated; in three systems, the circumsecondary disk is more massive than the circumprimary disk, counter to some theoretical predictions.

  16. Circumstellar disks around binary stars in Taurus

    Energy Technology Data Exchange (ETDEWEB)

    Akeson, R. L. [NASA Exoplanet Science Institute, IPAC/Caltech, Pasadena, CA 91125 (United States); Jensen, E. L. N. [Swarthmore College, Department of Physics and Astronomy, Swarthmore, PA 19081 (United States)

    2014-03-20

    We have conducted a survey of 17 wide (>100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10{sup –4} M {sub ☉}. We compare the properties of our sample to the population of known disks in Taurus and find that the disks from this binary sample match the scaling between stellar mass and millimeter flux of F{sub mm}∝M{sub ∗}{sup 1.5--2.0} to within the scatter found in previous studies. We also compare the properties of the primaries to those of the secondaries and find that the secondary/primary stellar and disk mass ratios are not correlated; in three systems, the circumsecondary disk is more massive than the circumprimary disk, counter to some theoretical predictions.

  17. How Nurses Experience Their Work as a Learning Environment

    OpenAIRE

    Skår, Randi

    2010-01-01

    This article explores and illuminates the meaning of nurses’ experiences with their work as a learning environment. A qualitative hermeneutic approach guided the research process and the analysis and interpretation of the transcribed interview-texts of eleven graduate nurses. Three core themes emerged from these informants’ descriptions of their work as a learning environment: ‘participation in the work community’, ‘to engage in interpersonal relations’ and ‘accessing important...

  18. Framework for Virtual Cognitive Experiment in Virtual Geographic Environments

    Directory of Open Access Journals (Sweden)

    Fan Zhang

    2018-01-01

    Full Text Available Virtual Geographic Environment Cognition is the attempt to understand the human cognition of surface features, geographic processes, and human behaviour, as well as their relationships in the real world. From the perspective of human cognition behaviour analysis and simulation, previous work in Virtual Geographic Environments (VGEs has focused mostly on representing and simulating the real world to create an ‘interpretive’ virtual world and improve an individual’s active cognition. In terms of reactive cognition, building a user ‘evaluative’ environment in a complex virtual experiment is a necessary yet challenging task. This paper discusses the outlook of VGEs and proposes a framework for virtual cognitive experiments. The framework not only employs immersive virtual environment technology to create a realistic virtual world but also involves a responsive mechanism to record the user’s cognitive activities during the experiment. Based on the framework, this paper presents two potential implementation methods: first, training a deep learning model with several hundred thousand street view images scored by online volunteers, with further analysis of which visual factors produce a sense of safety for the individual, and second, creating an immersive virtual environment and Electroencephalogram (EEG-based experimental paradigm to both record and analyse the brain activity of a user and explore what type of virtual environment is more suitable and comfortable. Finally, we present some preliminary findings based on the first method.

  19. Circumstellar Gas in Young Planetary Debris Disks

    Science.gov (United States)

    Roberge, A.

    Circumstellar (CS) disks orbiting young stars fall into two categories: primordial disks, composed of unprocessed interstellar dust and gas, and debris disks, produced by the destruction of solid planetary bodies. In the first class, the most abundant gas is H_2; in the second, it appears that the H_2 gas has disappeared, possibly through incorporation into gas giant planets. The lifetime of H_2 gas in a CS disk is therefore of great importance, as it dictates the timescale for the formation of giant planets. FUSE observations of H_2 in CS disk systems have shown that FUV absorption spectroscopy may sensitively probe for small amounts of gas along the line of sight to the star. Most importantly, the FUSE non-detection of H_2 gas in the Beta Pictoris disk suggests that the primordial gas lifetime is less than about 12 Myr, and that gas giant planets must form very quickly. However, this suggestion is based on one system, and needs to be tested in additional systems with a range of ages, especially since there are indications that age is not the only factor in the evolution of a CS disk. We propose for FUSE observations of 3 additional debris disk systems, Fomalhaut, HD3003, and HD2884. Fomalhaut is an intermediate age debris disk, one of the Fabulous Four CS disks first discovered in 1984. The other two disks are younger, with ages similar to that of Beta Pic. All three stars are brighter in the FUV than Beta Pic, permitting us to sensitively probe for traces of H_2 gas. We will also measure the amount of secondary atomic gas produced from planetary bodies in these disks, in an effort to understand the entire evolution of CS gas in young planetary systems.

  20. Procedural Zelda : A PCG Environment for Player Experience Research

    NARCIS (Netherlands)

    Heijne, Norbert; Bakkes, Sander

    2017-01-01

    To contribute to the domain of player experience research, this paper presents a new PCG environment with a relatively wide expressive range that builds upon the iconic The Legend of Zelda: A Link to the Past action-RPG game; it contributes by providing the openly-available Procedural Zelda

  1. The physics analysis environment of the ZEUS experiment

    International Nuclear Information System (INIS)

    Bauerdick, L.A.T.; Derugin, O.; Gilkinson, D.; Kasemann, M.; Manczak, O.

    1995-12-01

    The ZEUS Experiment has over the last three years developed its own model of the central computing environment for physics analysis. This model has been designed to provide ZEUS physicists with powerful and user friendly tools for data analysis as well as to be truly scalable and open. (orig.)

  2. The experience of demanding work environments in younger workers.

    Science.gov (United States)

    Winding, T N; Labriola, M; Nohr, E A; Andersen, J H

    2015-06-01

    Investigating whether certain individual or background characteristics are associated with an increased risk of experiencing an excessively demanding work environment in younger workers may help to reduce future inequality in health and maximize their labour market participation. To describe the work environment of Danish 20- to 21-year olds and to investigate the influence of family socioeconomic background and individual characteristics at age 14-15 on later experience of physical and psychosocial work environments. We obtained information on subjects' school performance, vulnerability, health and parental socioeconomic status from registers and a questionnaire completed in 2004. A questionnaire concerning eight measures of subjects' psychosocial and physical work environment in 2010 was used to determine the outcomes of interest. The study population consisted of 679 younger workers aged 20-21. The psychosocial work environment was in general good but younger workers experienced more demanding physical work than the general working population. Overall, individual as well as family factors had a limited impact on their assessment of the work environment. Low self-esteem at age 14-15 was associated with experiencing high demands and lack of trust and fairness at work, whereas low parental socioeconomic status was associated with a demanding physical work environment. This study showed a social gradient in experiencing a demanding physical work environment at age 20-21. The psychosocial work environment experienced by younger workers was generally good, but vulnerable young people may need special attention to protect them from or prepare them for psychosocially demanding jobs later in life. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. The experience of work in a call centre environment

    Directory of Open Access Journals (Sweden)

    Sanet Hauptfleisch

    2006-10-01

    Full Text Available This qualitative research study explored the work experience in a call centre environment in an information technology call centre based in South Africa, which service foreign customers exclusively. Three data collection methods were used, namely narratives, in-depth interviews with call centre consultants, and observation. Following a grounded theory approach, four themes were elicited, namely the perceptions of team members, uncertainty created by a constantly changing environment, perceived distances due to management practices, and depersonalisation experienced while actually dealing with customers. In addition to this, the reported impact of these themes on work performance was explored and compared to existing research.

  4. Multibeam smart antenna field trial experiments in mobile radio environments

    Science.gov (United States)

    Perini, Patrick

    1996-01-01

    Several types of high gain multibeam antennas were tested and compared to traditional sector and omni antennas in various mobile radio environments. A vehicle equipped with a mobile transmitter drove in several mobile radio environments while the received signal strength (RSS) was recorded on multiple antenna channels attached to multibeam, sector and omni directional antennas. The RSS data recorded included the fast (rayleigh) fading and was averaged into local means based on the mobile's position/speed. Description of the experiment and analysis of the gain improvement, average RSS, diversity gain are presented.

  5. The Living With a Star Space Environment Testbed Experiments

    Science.gov (United States)

    Xapsos, Michael A.

    2014-01-01

    The focus of the Living With a Star (LWS) Space Environment Testbed (SET) program is to improve the performance of hardware in the space radiation environment. The program has developed a payload for the Air Force Research Laboratory (AFRL) Demonstration and Science Experiments (DSX) spacecraft that is scheduled for launch in August 2015 on the SpaceX Falcon Heavy rocket. The primary structure of DSX is an Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA) ring. DSX will be in a Medium Earth Orbit (MEO). This oral presentation will describe the SET payload.

  6. Sample Environment in Experiments using X-Ray Synchrotron Radiation

    DEFF Research Database (Denmark)

    Buras, B

    1984-01-01

    beam experiments with wavelength chosen at will from the continuous spectrum. Another type of insertion device, called undulator produces quasi-monochromatic radiation. The insertion devices enable the tailoring of the emitted S.R. to the requirements of the users and can be treated as the first......Modern electron (positron) storage rings are able to emit very intense X-ray radiation with a continuous spectrum extending to 0.1 A, from bending magnets and insertion devices (wavelength shifters and multipole wigglers). It can be used directly for white beam experiments and/or for monochromatic...... optical element of the beam line. This feature is especially important for experiments with samples in special environment because the latter imposes limitations both on scattering and absorption experiments. However, these limitations can be minimized in each case by finding the best match between...

  7. Physical processes in circumstellar disks around young stars

    CERN Document Server

    2011-01-01

    Circumstellar disks are vast expanses of dust that form around new stars in the earliest stages of their birth. Predicted by astronomers as early as the eighteenth century, they weren't observed until the late twentieth century, when interstellar imaging technology enabled us to see nascent stars hundreds of light years away. Since then, circumstellar disks have become an area of intense study among astrophysicists, largely because they are thought to be the forerunners of planetary systems like our own-the possible birthplaces of planets.            This volume brings

  8. Lead-Free Experiment in a Space Environment

    Science.gov (United States)

    Blanche, J. F.; Strickland, S. M.

    2012-01-01

    This Technical Memorandum addresses the Lead-Free Technology Experiment in Space Environment that flew as part of the seventh Materials International Space Station Experiment outside the International Space Station for approximately 18 months. Its intent was to provide data on the performance of lead-free electronics in an actual space environment. Its postflight condition is compared to the preflight condition as well as to the condition of an identical package operating in parallel in the laboratory. Some tin whisker growth was seen on a flight board but the whiskers were few and short. There were no solder joint failures, no tin pest formation, and no significant intermetallic compound formation or growth on either the flight or ground units.

  9. Evaluation of the Radiation Environment of the LHCb Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00341385; Corti, Gloria

    The unprecedented radiation levels of the Large Hadron Collider (LHC) during high-energy proton-proton collisions will have an impact on the operation of its experiments’ detectors and electronics. LHCb, one of the 4 major LHC experiments, has started operation in 2009 and from 2011 onward it has been collecting data at and above its design luminosity. Detectors and associated detector electronics are prone to damage if the radiation levels exceed the expected values. It is essential to monitor the radiation environment of the experimental area and compare it with predictions obtained from simulation studies in order to assess the situation and take corrective action in case of need. Understanding the existing radiation environment will also provide important input to the planning of maintenance and for operation at upgrade luminosity. A set of radiation detectors has been installed in the LHCb experimental area to measure different aspects of its radiation environment. Passive dosimeters including Thermo-L...

  10. Designing Interactive Storytelling: A Virtual Environment for Personal Experience Narratives

    OpenAIRE

    Ladeira , Ilda; Marsden , Gary; Green , Lesley

    2011-01-01

    Part 1: Long and Short Papers; International audience; We describe an ongoing collaboration with the District Six Museum, in Cape Town, aimed at designing a storytelling prototype for preserving personal experience narratives. We detail the design of an interactive virtual environment (VE) which was inspired by a three month ethnography of real-life oral storytelling. The VE places the user as an audience member in a virtual group listening to two storytelling agents capable of two forms of i...

  11. The research of nuclear experiment radiation environment wireless alarm device

    International Nuclear Information System (INIS)

    Wang Xiaoqiong; Wang Pan; Fang Fang

    2009-01-01

    This article introduces based on monolithic integrated circuit's nuclear experiment radiation environment wireless alarm device's software and hardware design. The system by G-M tube, high-pressured module, signal conditioning circuit, power source module, monolithic integrated circuit and wireless transmission module is composed. The device has low power consumption, high performance, high accuracy detection, easy maintenance, small size, simple operation, and other features, and has a broad application prospects. (authors)

  12. Virtual experiment of optical spatial filtering in Matlab environment

    Science.gov (United States)

    Ji, Yunjing; Wang, Chunyong; Song, Yang; Lai, Jiancheng; Wang, Qinghua; Qi, Jing; Shen, Zhonghua

    2017-08-01

    The principle of spatial filtering experiment has been introduced, and the computer simulation platform with graphical user interface (GUI) has been made out in Matlab environment. Using it various filtering processes for different input image or different filtering purpose will be completed accurately, and filtering effect can be observed clearly with adjusting experimental parameters. The physical nature of the optical spatial filtering can be showed vividly, and so experimental teaching effect will be promoted.

  13. Circumstellar Disk Lifetimes In Numerous Galactic Young Stellar Clusters

    Science.gov (United States)

    Richert, A. J. W.; Getman, K. V.; Feigelson, E. D.; Kuhn, M. A.; Broos, P. S.; Povich, M. S.; Bate, M. R.; Garmire, G. P.

    2018-04-01

    Photometric detections of dust circumstellar disks around pre-main sequence (PMS) stars, coupled with estimates of stellar ages, provide constraints on the time available for planet formation. Most previous studies on disk longevity, starting with Haisch, Lada & Lada (2001), use star samples from PMS clusters but do not consider datasets with homogeneous photometric sensitivities and/or ages placed on a uniform timescale. Here we conduct the largest study to date of the longevity of inner dust disks using X-ray and 1-8 {μ m} infrared photometry from the MYStIX and SFiNCs projects for 69 young clusters in 32 nearby star-forming regions with ages t ≤ 5 Myr. Cluster ages are derived by combining the empirical AgeJX method with PMS evolutionary models, which treat dynamo-generated magnetic fields in different ways. Leveraging X-ray data to identify disk-free objects, we impose similar stellar mass sensitivity limits for disk-bearing and disk-free YSOs while extending the analysis to stellar masses as low as M ˜ 0.1 M⊙. We find that the disk longevity estimates are strongly affected by the choice of PMS evolutionary model. Assuming a disk fraction of 100% at zero age, the inferred disk half-life changes significantly, from t1/2 ˜ 1.3 - 2 Myr to t1/2 ˜ 3.5 Myr when switching from non-magnetic to magnetic PMS models. In addition, we find no statistically significant evidence that disk fraction varies with stellar mass within the first few Myr of life for stars with masses <2 M⊙, but our samples may not be complete for more massive stars. The effects of initial disk fraction and star-forming environment are also explored.

  14. The interaction of Type Ia supernovae with their circumstellar medium

    NARCIS (Netherlands)

    Chiotellis, A.

    2013-01-01

    This thesis is focused on the study of a specific class of supernovae, named Type Ia (or thermonuclear) supernovae. In particular, we attempt to gain information about their origin through the study of the interaction of these supernovae with circumstellar structures that have been shaped by their

  15. Herschel/HIFI deepens the circumstellar NH3 enigma

    NARCIS (Netherlands)

    Menten, K. M.; Wyrowski, F.; Alcolea, J.; De Beck, E.; Decin, L.; Marston, A. P.; Bujarrabal, V.; Cernicharo, J.; Dominik, C.; Justtanont, K.; de Koter, A.; Melnick, G.; Neufeld, D. A.; Olofsson, H.; Planesas, P.; Schmidt, M.; Schoier, F. L.; Szczerba, R.; Teyssier, D.; Waters, L. B. F. M.; Edwards, K.; Olberg, M.; Phillips, T. G.; Morris, P.; Salez, M.; Caux, E.

    2010-01-01

    Context. Circumstellar envelopes (CSEs) of a variety of evolved stars have been found to contain ammonia (NH3) in amounts that exceed predictions from conventional chemical models by many orders of magnitude. Aims. The observations reported here were performed in order to better constrain the NH3

  16. Variable circumstellar obscuration of the carbon star R Fornacis

    International Nuclear Information System (INIS)

    Feast, M.W.; Whitelock, P.A.; Catchpole, R.M.; Roberts, G.; Overbeek, M.D.

    1984-01-01

    In 1983 the carbon Mira-type variable R For became unusually faint in the visible and infrared. This is interpreted as a change in circumstellar obscuration. For absorption by graphite spheres the required particle radius is 0.15 μm. (author)

  17. Lesbian, Gay, and Heterosexual Adoptive Parents' Experiences in Preschool Environments.

    Science.gov (United States)

    Goldberg, Abbie E

    2014-01-01

    Little research has examined the school experiences of lesbian/gay (LG) parent families or adoptive parent families. The current exploratory study examined the experiences of 79 lesbian, 75 gay male, and 112 heterosexual adoptive parents of preschool-age children with respect to their (a) level of disclosure regarding their LG parent and adoptive family status at their children's schools; (b) perceived challenges in navigating the preschool environment and advocating on behalf of their children and families; and (c) recommendations to teachers and schools about how to create affirming school environments with respect to family structure, adoption, and race/ethnicity. Findings revealed that the majority of parents were open about their LG and adoptive family status, and had not encountered challenges related to family diversity. Those parents who did experience challenges tended to describe implicit forms of marginalization, such as insensitive language and school assignments. Recommendations for teachers included discussing and reading books about diverse families, tailoring assignments to meet the needs of diverse families, and offering school community-building activities and events to help bridge differences across families.

  18. High-dependency care: experiences of the psychosocial work environment.

    Science.gov (United States)

    Rahman, Hanif Abdul; Naing, Lin; Abdul-Mumin, Khadizah

    2017-11-23

    to explore high-dependency care nurses' experiences of their psychosocial work environment. four focus groups were conducted with 23 emergency and critical care hospital nurses in Brunei. All sessions were recorded, transcribed verbatim and analysed using inductive-approach thematic analysis. three major themes were identified. 'Specialisation/specific skills' explained a fundamental requirement for the high-dependency care nurses to work effectively and efficiently in their workplace. 'Task completion' narrated the pressure they experienced to complete their tasks within time constraints exacerbated by a reduced number of staff. 'Acknowledgement' signified their need for fair and adequate reward for their hard work through career progression and promotion. this study facilitates the design of future interventions and policies that promote a healthy psychosocial work environment by ensuring nurses working in these areas have the required specialisation skills, there is a balance of workload and nurse-to-patient ratios, and they are offered fairness and equity in career progression and promotion.

  19. Discovery of a Circumstellar Disk in the Lagoon Nebula

    Science.gov (United States)

    1997-04-01

    Circumstellar disks of gas and dust play a crucial role in the formation of stars and planets. Until now, high-resolution images of such disks around young stars within the Orion Nebula obtained with the Hubble Space Telescope (HST) constituted the most direct proof of their existence. Now, another circumstellar disk has been detected around a star in the Lagoon Nebula - also known as Messier 8 (M8) , a giant complex of interstellar gas and dust with many young stars in the southern constellation of Sagittarius and four times more distant than the Orion Nebula. The observations were carried out by an international team of scientists led by Bringfried Stecklum (Thüringer Landessternwarte, Tautenburg, Germany) [1] who used telescopes located at the ESO La Silla observatory and also observations from the HST archive. These new results are paving the road towards exciting research programmes on star formation which will become possible with the ESO Very Large Telescope. The harsh environment of circumstellar disks The existence of circumstellar disks has been inferred from indirect measurements of young stellar objects, such as the spectral energy distribution, the analysis of the profiles of individual spectral lines and measurements of the polarisation of the emitted light [2]. Impressive images of such disks in the Orion Nebula, known as proplyds (PROto-PLanetarY DiskS), have been obtained by the HST during the recent years. They have confirmed the interpretation of previous ground-based emission-line observations and mapping by radio telescopes. Moreover, they demonstrated that those disks which are located close to hot and massive stars are subject to heating caused by the intense radiation from these stars. Subsequently, the disks evaporate releasing neutral gas which streams off. During this process, shock fronts (regions with increased density) with tails of ionised gas result at a certain distance between the disk and the hot star. These objects appear on

  20. Gas phase chemical kinetics at high temperature of carbonaceous molecules: application to circumstellar envelopes

    Science.gov (United States)

    Biennier, L.; Gardez, A.; Saidani, G.; Georges, R.; Rowe, B.; Reddy, K. P. J.

    2011-05-01

    Circumstellar shells of evolved stars are a theater of extremely rich physical and chemical processes. More than seventy molecules of varied nature have been identified in the envelopes through their spectral fingerprints in the microwave or far infrared regions. Many of them are carbon chain molecules and radicals and a significant number are unique to the circumstellar medium. However, observational data remain scarce and more than half of the detected species have been observed in only one object, the nearby carbon star IRC + 10216. Chemical kinetic models are needed to describe the formation of molecules in evolved circumstellar outflows. Upcoming terrestrial telescopes such as ALMA will increase the spatial resolution by several orders of magnitude and provide a wealth of data. The determination of relevant laboratory kinetics data is critical to keep up with the development of the observations and of the refinement of chemical models. Today, the majority of reactions studied in the laboratory are the ones involved in combustion and concerning light hydrocarbons. Our objective is to provide the scientific community with rate coefficients of reactions between abundant species in these warm environments. Cyanopolyynes from HC_2N to HC_9N have all been detected in carbon rich circumstellar envelopes in up to 10 sources for HC_3N. Neutral-neutral reactions of the CN radical with unsaturated hydrocarbons could be a dominant route in the formation of cyanopolyynes, even at low temperatures. Our approach aims to bridge the temperature gap between resistively heated flow tubes and shock tubes. The present kinetic measurements are obtained using a new reactor combining a high enthalpy source (Moudens et al. 2011) with a flow tube and a pulsed laser photolysis and laser induced fluorescence system to probe the undergoing chemical reactions. The high enthalpy flow tube has been used to measure the rate constant of the reaction of the CN radical with propane, propene

  1. Teachers' experiences of teaching in a blended learning environment.

    Science.gov (United States)

    Jokinen, Pirkko; Mikkonen, Irma

    2013-11-01

    This paper considers teachers' experiences of teaching undergraduate nursing students in a blended learning environment. The basic idea of the study programme was to support students to reflect on theory and practice, and provide with access to expert and professional knowledge in real-life problem-solving and decision making. Learning was organised to support learning in and about work: students worked full-time and this provided excellent opportunities for learning both in practice, online and face-to-face sessions. The aim of the study was to describe teachers' experiences of planning and implementing teaching and learning in a blended-learning-based adult nursing programme. The research method was qualitative, and the data were collected by three focus group interviews, each with four to six participants. The data were analysed using qualitative content analysis. The results show that the blended learning environment constructed by the combination of face-to-face learning and learning in practice with technology-mediated learning creates challenges that must be taken into consideration when planning and implementing blended teaching and learning. However, it provides good opportunities to enhance students' learning in and about work. This is because such programmes support student motivation through the presence of "real-life" and their relevance to the students' own places of work. Nevertheless, teachers require knowledge of different pedagogical approaches; they need professional development support in redesigning teaching and learning. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Clinical Education Environment Experiences of Operating Room Students

    Directory of Open Access Journals (Sweden)

    Tahereh khazaei

    2016-01-01

    Full Text Available Background and purpose: The objective of medical education is to train competent and qualified workforce in order to provide services in various health environments. One of the important objectives of Operating Room students is to train workforce who can involve in patient’s health and recovery. Training these students should cause clinical ability and independent decision making during surgery. Since students during internship face with many problems, this study has been conducted to explore and describe the challenges and experiences.Methods: This qualitative study is a phenomenology that was conducted based on 20 students in the last semester of Operating Room associate’s degree with purposive sampling. Deep and semi-structured interviews were used to collect data and data were analyzed by content analysis method.Results: The findings in 5 main themes: (1 Physical space and equipment in the operating room, (2 The student’s position in operating room, (3 Integrating knowledge and action, (4 Managing education environment and 5- Student’s viewpoint about operating room and working in it.Conclusions: Interviews with students revealed the educational environment challenges with which they are faced during their study. Teachers can provide solutions to overcome the challenges and create a positive atmosphere for students' learning using results of this study and students may continue their interest in education and improve the quality of their education.Keywords: CLINICAL EDUCATION, OPERATING ROOM STUDENTS, CHALLENGE

  3. A User-Centric View of Intelligent Environments: User Expectations, User Experience and User Role in Building Intelligent Environments

    Directory of Open Access Journals (Sweden)

    Eija Kaasinen

    2012-12-01

    Full Text Available Our everyday environments are gradually becoming intelligent, facilitated both by technological development and user activities. Although large-scale intelligent environments are still rare in actual everyday use, they have been studied for quite a long time, and several user studies have been carried out. In this paper, we present a user-centric view of intelligent environments based on published research results and our own experiences from user studies with concepts and prototypes. We analyze user acceptance and users’ expectations that affect users’ willingness to start using intelligent environments and to continue using them. We discuss user experience of interacting with intelligent environments where physical and virtual elements are intertwined. Finally, we touch on the role of users in shaping their own intelligent environments instead of just using ready-made environments. People are not merely “using” the intelligent environments but they live in them, and they experience the environments via embedded services and new interaction tools as well as the physical and social environment. Intelligent environments should provide emotional as well as instrumental value to the people who live in them, and the environments should be trustworthy and controllable both by regular users and occasional visitors. Understanding user expectations and user experience in intelligent environments, and providing users with tools to influence the environments can help to shape the vision of intelligent environments into meaningful, acceptable and appealing service entities for all those who live and act in them.

  4. GumTree-An integrated scientific experiment environment

    International Nuclear Information System (INIS)

    Lam, Tony; Hauser, Nick; Goetz, Andy; Hathaway, Paul; Franceschini, Fredi; Rayner, Hugh; Zhang, Lidia

    2006-01-01

    GumTree is an open source and multi-platform graphical user interface for performing neutron scattering and X-ray experiments. It handles the complete experiment life cycle from instrument calibration, data acquisition, and real time data analysis to results publication. The aim of the GumTree Project is to create a highly Integrated Scientific Experiment Environment (ISEE), allowing interconnectivity and data sharing between different distributed components such as motors, detectors, user proposal database and data analysis server. GumTree is being adapted to several instrument control server systems such as TANGO, EPICS and SICS, providing an easy-to-use front-end for users and simple-to-extend model for software developers. The design of GumTree is aimed to be reusable and configurable for any scientific instrument. GumTree will be adapted to six neutron beam instruments for the OPAL reactor at ANSTO. Other European institutes including ESRF, ILL and PSI have shown interest in using GumTree as their workbench for instrument control and data analysis

  5. GumTree - An Integrated Scientific Experiment Environment

    International Nuclear Information System (INIS)

    Lam, Tony; Hauser, Nick; Hathaway, Paul; Franceschini, Fredi; Rayner, Hugh; Zhang, Lidia; Goetz, Andy

    2005-01-01

    Full text: GumTree is an open source and multi-platform graphical user interface for performing neutron scattering and X-ray experiments. It handles the complete experiment life cycle from instrument calibration, data acquisition, and real time data analysis to results publication. The aim of the GumTree Project is to create a highly Integrated Scientific Experiment Environment (ISEE), allowing interconnectivity and data sharing between different distributed components such as motors, detectors, user proposal database and data analysis server. GumTree is being adapted to several instrument control server systems such as TANGO, EPICS and SICS, providing an easy-to-use front-end for users and simple-to-extend model for software developers. The design of GumTree is aimed to be reusable and configurable for any scientific instrument. GumTree will be adapted to six neutron beam instruments for the OPAL reactor at ANSTO. Other European institutes including ESRF, ILL and PSI have shown interest in using GumTree as their workbench for instrument control and data analysis. (authors)

  6. Experience of the Paris Research Consortium Climate-Environment-Society

    Science.gov (United States)

    Joussaume, Sylvie; Pacteau, Chantal; Vanderlinden, Jean Paul

    2016-04-01

    It is now widely recognized that the complexity of climate change issues translates itself into a need for interdisciplinary approaches to science. This allows to first achieve a more comprehensive vision of climate change and, second, to better inform the decision-making processes. However, it seems that willingness alone is rarely enough to implement interdisciplinarity. The purpose of this presentation is to mobilize reflexivity to revisit and analyze the experience of the Paris Consortium for Climate-Environment-Society. The French Consortium Climate-Environment-Society aims to develop, fund and coordinate interdisciplinary research into climate change and its impacts on society and environment. Launched in 2007, the consortium relies on the research expertise of 17 laboratories and federation in the Paris area working mainly in the fields of climatology, hydrology, ecology, health sciences, and the humanities and social sciences. As examples, economists and climatologists have studied greenhouse gas emission scenarios compatible with climate stabilization goals. Historical records have provided both knowledge about past climate change and vulnerability of societies. Some regions, as the Mediterranean and the Sahel, are particularly vulnerable and already have to cope with water availability, agricultural production and even health issues. A project showed that millet production in West Africa is expected to decline due to warming in a higher proportion than observed in recent decades. Climate change also raises many questions concerning health: combined effects of warming and air quality, impacts on the production of pollens and allergies, impacts on infectious diseases. All these issues lead to a need for approaches integrating different disciplines. Furthermore, climate change impacts many ecosystems which, in turn, affect its evolution. Our experience shows that interdisciplinarity supposes, in order to take shape, the conjunction between programming

  7. The chemistry of molecular anions in circumstellar sources

    Energy Technology Data Exchange (ETDEWEB)

    Agúndez, Marcelino [LUTH, Observatoire de Paris-Meudon, 5 Place Jules Janssen, 92190 Meudon (France); Cernicharo, José [Departamento de Astrofísica, CAB, CSIC-INTA, Ctra. de Torrejón a Ajalvir km 4, 28850 Madrid (Spain); Guélin, Michel [Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 Saint Martin d' Héres (France)

    2015-01-22

    The detection of negatively charged molecules in the interstellar and circumstellar medium in the past four years has been one of the most impacting surprises in the area of molecular astrophysics. It has motivated the interest of astronomers, physicists, and chemists on the study of the spectroscopy, chemical kinetics, and prevalence of molecular anions in the different astronomical regions. Up to six different molecular anions have been discovered in space to date, the last one being the small ion CN{sup −}, which has been observed in the envelope of the carbon star IRC +10216 and which contrary to the other larger anions is not formed by electron attachment to CN, but through reactions of large carbon anions with nitrogen atoms. Here we briefly review the current status of our knowledge of the chemistry of molecular anions in space, with particular emphasis on the circumstellar source IRC +10216, which to date is the astronomical source harboring the largest variety of anions.

  8. Observations of Circumstellar Thermochemical Equilibrium: The Case of Phosphorus

    Science.gov (United States)

    Milam, Stefanie N.; Charnley, Steven B.

    2011-01-01

    We will present observations of phosphorus-bearing species in circumstellar envelopes, including carbon- and oxygen-rich shells 1. New models of thermochemical equilibrium chemistry have been developed to interpret, and constrained by these data. These calculations will also be presented and compared to the numerous P-bearing species already observed in evolved stars. Predictions for other viable species will be made for observations with Herschel and ALMA.

  9. Circumstellar X-ray Emission from SN1978K

    Science.gov (United States)

    Schlegel, Eric M.; Colbert, E.; Petre, R.

    1995-02-01

    We present the X-ray light curve in the 0.2 2.4 keV band based on fiveROSAT observations of SN1978K in NGC 1313. The X-ray emission is believed to arise from the interaction of the reverse shock and the expanding debris from the supernova. The reverse shock becomes established after the outgoing shock runs into circumstellar matter.

  10. Ultraviolet extinction in M-supergiant circumstellar envelopes

    International Nuclear Information System (INIS)

    Buss, R.H. Jr.; Snow, T.P. Jr.

    1986-01-01

    Using International Ultraviolet (IUS) archival low-dispersion spectra, ultraviolet spectral extinctions were derived for the circumstellar envelopes of two M supergiants: HD 60414 and HD 213310. The observed stellar systems belong to a class of widely-separated spectroscopic binaries that are called VV Cephei stars. The total extinction was calculated by dividing the reddened fluxes with unreddened comparison fluxes of similar stars (g B2.5 for HD 213310 and a normalized s+B3 for HD 60414) from the reference atlas. After substracting the interstellar extinctions, which were estimated from the E(B-V) reddening of nearby stars, the resultant circumstellar extinctions were normalized at about 3.5 inverse microns. Not only is the 2175 A extinction bump absent in the circumstellar extinctions, but the far-ultraviolet extinction rise is also absent. The rather flat, ultraviolet extinction curves were interpreted as signatures of a population of noncarbonaceous, oxygen-rich grains with diameters larger than the longest observed wavelength

  11. Enantiomeric separation of complex organic molecules produced from irradiation of interstellar/circumstellar ice analogs

    Science.gov (United States)

    Nuevo, M.; Meierhenrich, U. J.; D'Hendecourt, L.; Muñoz Caro, G. M.; Dartois, E.; Deboffle, D.; Thiemann, W. H.-P.; Bredehöft, J.-H.; Nahon, L.

    Irradiation of interstellar/circumstellar ice analogs by ultraviolet (UV) light followed by warm up in the laboratory leads to the formation of complex organic molecules, stable at room temperature. Hydrolysis of the room temperature residue releases amino acids, the building blocks of proteins. These amino acids exist in two different forms (L and D), but proteins encountered in living beings consist exclusively of L enantiomers. The origin of this property, called homochirality, is still unknown. Amino acids can be detected and quantified by chemical techniques such as chiral gas chromatography coupled with mass spectrometry (GC-MS). Enantiomers of chiral organics are also known to interact selectively with circularly polarized light (CPL), leading to a selective production or destruction of the final compounds. This paper describes how we settled an experiment where amino acids are formed by irradiation of interstellar/circumstellar ice analogs with ultraviolet (UV) CPL, produced by a synchrotron radiation beamline, which allowed us to quantify the effect of such polarized light on the production of amino acids. These results can be compared to the enantiomeric excesses measured in primitive meteorites such as Murchison.

  12. School Nurses' Experiences and Perceptions of Healthy Eating School Environments.

    Science.gov (United States)

    Muckian, Jean; Snethen, Julia; Buseh, Aaron

    School nurses provide health promotion and health services within schools, as healthy children have a greater potential for optimal learning. One of the school nurses' role is in encouraging healthy eating and increasing the availability of fruits and vegetables in the school. The purpose of this study was to explore and describe school nurses' perceptions of their role in promoting increased fruit and vegetable consumption in the school setting. One avenue to increased availability of fruits and vegetables in schools is Farm to School programs mandated by the Federal government to improve the health of school children. School nurses are optimally positioned to work with Farm to School programs to promote healthy eating. A secondary aim was to explore school nurses' knowledge, experiences and/or perceptions of the Farm to School program to promote fruit and vegetable consumption in the school setting. Three themes emerged from the focus groups: If There Were More of Me, I Could Do More; Food Environment in Schools; School Nurses Promote Health. School nurses reported that they addressed health issues more broadly in their roles as educator, collaborator, advocate and modeling healthy behaviors. Most of the participants knew of Farm to School programs, but only two school nurses worked in schools that participated in the program. Consequently, the participants reported having little or no experiences with the Farm to School programs. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Simulated learning environment experience in nursing students for paediatric practice.

    Science.gov (United States)

    Mendoza-Maldonado, Yessy; Barría-Pailaquilén, René Mauricio

    The training of health professionals requires the acquisition of clinical skills in a safe and efficient manner, which is facilitated by a simulated learning environment (SLE). It is also an efficient alternative when there are limitations for clinical practice in certain areas. This paper shows the work undertaken in a Chilean university in implementing paediatric practice using SLE. Over eight days, the care experience of a hospitalized infant was studied applying the nursing process. The participation of a paediatrician, resident physician, nursing technician, and simulated user was included in addition to the use of a simulation mannequin and equipment. Simulation of care was integral and covered interaction with the child and family and was developed in groups of six students by a teacher. The different phases of the simulation methodology were developed from a pedagogical point of view. The possibility of implementing paediatric clinical practice in an efficient and safe way was confirmed. The experience in SLE was highly valued by the students, allowing them to develop different skills and abilities required for paediatric nursing through simulation. Copyright © 2018 Elsevier España, S.L.U. All rights reserved.

  14. Real-time control environment for the RFX experiment

    International Nuclear Information System (INIS)

    Barana, O.; Cavinato, M.; Luchetta, A.; Manduchi, G.; Taliercio, C.

    2005-01-01

    A comprehensive set of control schemes can be presently implemented on RFX due to the enhanced load assembly and renewed power supply system. The schemes include: plasma equilibrium control and resistive wall mode stabilization, aiming at controlling actively the discharge when the passive action of the shell vanishes; the rotation of the localised helical deformation to minimize the enhanced plasma-wall interaction; the MHD mode control and the 'intelligent shell', aiming at achieving a better comprehension of the underlying physics. To the purpose, an integrated, distributed, digital system has been developed consisting of a set of computing nodes. Each node can act either as pre-processing or control station, the former acquiring raw data and computing intermediate control parameters, the latter executing control algorithms and driving the power amplifiers. An overview of the system architecture is presented in the paper with reference to the software real-time environment providing both basic functions, such as data read-out and real-time communication, and useful tools to program control algorithms, to perform simulations and to commission the system. To simulate the control schemes, the real-time environment is extended to include a so called 'simulation mode', in which the real-time nodes exchange their input/output signals with one station running a suitable model of the experiment, for instance the two dimensional FEM code MAXFEA in the case of the equilibrium control. In this way the control system can be tested offline and the time needed for the commissioning of algorithms reduced

  15. Experiments with microcomputer-based artificial intelligence environments

    Science.gov (United States)

    Summers, E.G.; MacDonald, R.A.

    1988-01-01

    The U.S. Geological Survey (USGS) has been experimenting with the use of relatively inexpensive microcomputers as artificial intelligence (AI) development environments. Several AI languages are available that perform fairly well on desk-top personal computers, as are low-to-medium cost expert system packages. Although performance of these systems is respectable, their speed and capacity limitations are questionable for serious earth science applications foreseen by the USGS. The most capable artificial intelligence applications currently are concentrated on what is known as the "artificial intelligence computer," and include Xerox D-series, Tektronix 4400 series, Symbolics 3600, VAX, LMI, and Texas Instruments Explorer. The artificial intelligence computer runs expert system shells and Lisp, Prolog, and Smalltalk programming languages. However, these AI environments are expensive. Recently, inexpensive 32-bit hardware has become available for the IBM/AT microcomputer. USGS has acquired and recently completed Beta-testing of the Gold Hill Systems 80386 Hummingboard, which runs Common Lisp on an IBM/AT microcomputer. Hummingboard appears to have the potential to overcome many of the speed/capacity limitations observed with AI-applications on standard personal computers. USGS is a Beta-test site for the Gold Hill Systems GoldWorks expert system. GoldWorks combines some high-end expert system shell capabilities in a medium-cost package. This shell is developed in Common Lisp, runs on the 80386 Hummingboard, and provides some expert system features formerly available only on AI-computers including frame and rule-based reasoning, on-line tutorial, multiple inheritance, and object-programming. ?? 1988 International Association for Mathematical Geology.

  16. Orion EFT-1 Cavity Heating Tile Experiments and Environment Reconstruction

    Science.gov (United States)

    Salazar, Giovanni; Amar, Adam; Oliver, Brandon; Hyatt, Andrew; Rezin, Marc

    2016-01-01

    Developing aerothermodynamic environments for deep cavities, such as those produced by micrometeoroids and orbital debris impacts, poses a great challenge for engineers. In order to assess existing cavity heating models, two one-inch diameter cavities were flown on the Orion Multi-Purpose Crew Vehicle during Exploration Flight Test 1 (EFT1). These cavities were manufactured with depths of 1.0 in and 1.4 in, and they were both instrumented. Instrumentation included surface thermocouples upstream, downstream and within the cavities, and additional thermocouples at the TPS-structure interface. This paper will present the data obtained, and comparisons with computational predictions will be shown. Additionally, the development of a 3D material thermal model will be described, which will be used to account for the three-dimensionality of the problem when interpreting the data. Furthermore, using a multi-dimensional inverse heat conduction approach, a reconstruction of a time- and space-dependent flight heating distribution during EFT1 will be presented. Additional discussions will focus on instrumentation challenges and calibration techniques specific to these experiments. The analysis shown will highlight the accuracies and/or deficiencies of current computational techniques to model cavity flows during hypersonic re-entry.

  17. The Experience of Fluid Temporality in Adaptive Lighting Environments

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper

    2013-01-01

    The paper presents research on the experiential qualities emerging from the performative engagement within adaptive lighting environments. Being performatively engaged in an environment, where the lighting is continuously adapting, opens an experiential position with fuid temporality, and opens...... of adaptive lighting environments through the lighting research and designs of the four authors....

  18. Circumstellar Interaction in Supernovae in Dense Environments—An Observational Perspective

    Science.gov (United States)

    Chandra, Poonam

    2018-02-01

    In a supernova explosion, the ejecta interacting with the surrounding circumstellar medium (CSM) give rise to variety of radiation. Since CSM is created from the mass loss from the progenitor, it carries footprints of the late time evolution of the star. This is one of the unique ways to get a handle on the nature of the progenitor system. Here, I will focus mainly on the supernovae (SNe) exploding in dense environments, a.k.a. Type IIn SNe. Radio and X-ray emission from this class of SNe have revealed important modifications in their radiation properties, due to the presence of high density CSM. Forward shock dominance in the X-ray emission, internal free-free absorption of the radio emission, episodic or non-steady mass loss rate, and asymmetry in the explosion seem to be common properties of this class of SNe.

  19. Distribution coefficients for radionuclides in aquatic environments. Volume 2. Dialysis experiments in marine environments

    International Nuclear Information System (INIS)

    Sibley, T.H.; Nevissi, A.E.; Schell, W.R.

    1981-05-01

    The overall objective of this research program was to obtain new information that can be used to predict the fate of radionuclides that may enter the aquatic environment from nuclear power plants, waste storage facilities or fuel reprocessing plants. Important parameters for determining fate are the distribution of radionuclides between the soluble and particulate phases and the partitioning of radionuclides among various suspended particulates. This report presents the results of dialysis experiments that were used to study the distribution of radionuclides among suspended sediments, phytoplankton, organic detritus, and filtered sea water. Three experiments were conducted to investigate the adsorption kinetics and equilibrium distribution of (59)Fe, (60)Co, (65)Zn, (106)Ru, (137)Cs, (207)Bi, (238)Pu, and (241)Am in marine system. Diffusion across the dialysis membranes depends upon the physico-chemical form of the radionuclides, proceeding quite rapidly for ionic species of (137)Cs and (60)Co but much more slowly for radionuclides which occur primarily as colloids and solid precipitates such as (59)Fe, (207)Bi, and (241)Am. All the radionuclides adsorb to suspended particulates although the amount of adsorption depends upon the specific types and concentration of particulates in the system and the selected radionuclide. High affinity of some radionuclides - e.g., (106)Ru and (241)Am - for detritus and phytoplankton suggests that suspended organics may significantly affect the eventual fate of those radionuclides in marine ecosystems

  20. DYNAMICS OF CIRCUMSTELLAR DISKS. III. THE CASE OF GG Tau A

    International Nuclear Information System (INIS)

    Nelson, Andrew F.; Marzari, F.

    2016-01-01

    We present two-dimensional hydrodynamic simulations using the Smoothed Particle Hydrodynamic code, VINE, to model a self-gravitating binary system. We model configurations in which a circumbinary torus+disk surrounds a pair of stars in orbit around each other and a circumstellar disk surrounds each star, similar to that observed for the GG Tau A system. We assume that the disks cool as blackbodies, using rates determined independently at each location in the disk by the time dependent temperature of the photosphere there. We assume heating due to hydrodynamical processes and to radiation from the two stars, using rates approximated from a measure of the radiation intercepted by the disk at its photosphere. We simulate a suite of systems configured with semimajor axes of either a = 62 AU (“wide”) or a = 32 AU (“close”), and with assumed orbital eccentricity of either e = 0 or e = 0.3. Each simulation follows the evolution for ∼6500–7500 yr, corresponding to about three orbits of the torus around the center of mass. Our simulations show that strong, sharply defined spiral structures are generated from the stirring action of the binary and that, in some cases, these structures fragment into 1–2 massive clumps. The torus quickly fragments into several dozen such fragments in configurations in which either the binary is replaced by a single star of equal mass, or radiative heating is neglected. The spiral structures extend inwards to the circumstellar environment as large scale material streams for which most material is found on trajectories that return it to the torus on a timescale of 1–200 yr, with only a small fraction accreting into the circumstellar environment. The spiral structures also propagate outwards through the torus, generating net outwards mass flow, and eventually losing coherence at large distances from the stars. The torus becomes significantly eccentric in shape over most of its evolution. In all configurations, accretion onto the

  1. DYNAMICS OF CIRCUMSTELLAR DISKS. III. THE CASE OF GG Tau A

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Andrew F. [XCP-2, Mailstop T082, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Marzari, F., E-mail: andy.nelson@lanl.gov, E-mail: francesco.marzari@pd.infn.it [Università di Padova, Dipartimento di Fisica, via Marzolo 8, 35131 Padova (Italy)

    2016-08-20

    We present two-dimensional hydrodynamic simulations using the Smoothed Particle Hydrodynamic code, VINE, to model a self-gravitating binary system. We model configurations in which a circumbinary torus+disk surrounds a pair of stars in orbit around each other and a circumstellar disk surrounds each star, similar to that observed for the GG Tau A system. We assume that the disks cool as blackbodies, using rates determined independently at each location in the disk by the time dependent temperature of the photosphere there. We assume heating due to hydrodynamical processes and to radiation from the two stars, using rates approximated from a measure of the radiation intercepted by the disk at its photosphere. We simulate a suite of systems configured with semimajor axes of either a = 62 AU (“wide”) or a = 32 AU (“close”), and with assumed orbital eccentricity of either e = 0 or e = 0.3. Each simulation follows the evolution for ∼6500–7500 yr, corresponding to about three orbits of the torus around the center of mass. Our simulations show that strong, sharply defined spiral structures are generated from the stirring action of the binary and that, in some cases, these structures fragment into 1–2 massive clumps. The torus quickly fragments into several dozen such fragments in configurations in which either the binary is replaced by a single star of equal mass, or radiative heating is neglected. The spiral structures extend inwards to the circumstellar environment as large scale material streams for which most material is found on trajectories that return it to the torus on a timescale of 1–200 yr, with only a small fraction accreting into the circumstellar environment. The spiral structures also propagate outwards through the torus, generating net outwards mass flow, and eventually losing coherence at large distances from the stars. The torus becomes significantly eccentric in shape over most of its evolution. In all configurations, accretion onto the

  2. Light-scattering models applied to circumstellar dust properties

    International Nuclear Information System (INIS)

    Koehler, Melanie; Mann, Ingrid

    2004-01-01

    Radiation pressure force, Poynting-Robertson effect, and collisions are important to determine the size distribution of dust in circumstellar debris disks with the two former parameters depending on the light-scattering properties of grains. We here present Mie and discrete-dipole approximation (DDA) calculations to describe the optical properties of dust particles around β Pictoris, Vega, and Fomalhaut in order to study the influence of the radiation pressure force. We find that the differences between Mie and DDA calculations are lower than 30% for all porosities. Therefore, Mie calculations can be used to determine the cut-off limits which contribute to the size distribution for the different systems

  3. Circumstellar Material on and off the Main Sequence

    Science.gov (United States)

    Steele, Amy; Debes, John H.; Deming, Drake

    2017-06-01

    There is evidence of circumstellar material around main sequence, giant, and white dwarf stars that originates from the small-body population of planetary systems. These bodies tell us something about the chemistry and evolution of protoplanetary disks and the planetary systems they form. What happens to this material as its host star evolves off the main sequence, and how does that inform our understanding of the typical chemistry of rocky bodies in planetary systems? In this talk, I will discuss the composition(s) of circumstellar material on and off the main sequence to begin to answer the question, “Is Earth normal?” In particular, I look at three types of debris disks to understand the typical chemistry of planetary systems—young debris disks, debris disks around giant stars, and dust around white dwarfs. I will review the current understanding on how to infer dust composition for each class of disk, and present new work on constraining dust composition from infrared excesses around main sequence and giant stars. Finally, dusty and polluted white dwarfs hold a unique key to our understanding of the composition of rocky bodies around other stars. In particular, I will discuss WD1145+017, which has a transiting, disintegrating planetesimal. I will review what we know about this system through high speed photometry and spectroscopy and present new work on understanding the complex interplay of physics that creates white dwarf pollution from the disintegration of rocky bodies.

  4. Are young supernova remnants interacting with circumstellar gas

    International Nuclear Information System (INIS)

    Chevalier, R.A.

    1982-01-01

    The young remnants of galactic Type I supernovae (SN 1006, SN 1572, and SN 1604) appear to be interacting with moderately dense gas (n/sub O/> or =0.1 cm -3 ). If the gas in the ambient interstellar medium, the observations suggest that gas of this density is fairly pervasive. If the gas is circumstellar, there are important implications for the progenitors of Type I supernovae. A plausible density distribution for circumstellar gas is rhoinfinityr -2 . The expansion of a supernova into such a medium is examined and is compared with expansion into a uniform medium. The two cases can be distinguished on the basis of their density profiles and their rates of expansion. Currently available data factor the hypothesis of expansion in a uniform medium for all three Type I remnants; the evidence is the strongest for SN 1572 and the weakest for SN 1604. Further X-ray and radio observations of the galactic remnants and of extragalactic Type I supernovae should serve to test this hypothesis

  5. The experience of demanding work environments in younger workers

    DEFF Research Database (Denmark)

    Winding, Trine Nøhr; Labriola, Merete; Nohr, Ellen Aagaard

    2015-01-01

    younger workers aged 20-21. The psychosocial work environment was in general good but younger workers experienced more demanding physical work than the general working population. Overall, individual as well as family factors had a limited impact on their assessment of the work environment. Low self-esteem...... at age 20-21. The psychosocial work environment experienced by younger workers was generally good, but vulnerable young people may need special attention to protect them from or prepare them for psychosocially demanding jobs later in life....

  6. A circumstellar molecular gas structure associated with the massive young star Cepheus A-HW 2

    Science.gov (United States)

    Torrelles, Jose M.; Rodriguez, Luis F.; Canto, Jorge; Ho, Paul T. P.

    1993-01-01

    We report the detection via VLA-D observations of ammonia of a circumstellar high-density molecular gas structure toward the massive young star related to the object Cepheus A-HW 2, a firm candidate for the powering source of the high-velocity molecular outflow in the region. We suggest that the circumstellar molecular gas structure could be related to the circumstellar disk previously suggested from infrared, H2O, and OH maser observations. We consider as a plausible scenario that the double radio continuum source of HW 2 could represent the ionized inner part of the circumstellar disk, in the same way as proposed to explain the double radio source in L1551. The observed motions in the circumstellar molecular gas can be produced by bound motions (e.g., infall or rotation) around a central mass of about 10-20 solar masses (B0.5 V star or earlier).

  7. Early results of experiments with responsive open learning environments

    OpenAIRE

    Friedrich, M.; Wolpers, M.; Shen, R.; Ullrich, C.; Klamma, R.; Renzel, D.; Richert, A.; Heiden, B. von der

    2011-01-01

    Responsive open learning environments (ROLEs) are the next generation of personal learning environments (PLEs). While PLEs rely on the simple aggregation of existing content and services mainly using Web 2.0 technologies, ROLEs are transforming lifelong learning by introducing a new infrastructure on a global scale while dealing with existing learning management systems, institutions, and technologies. The requirements engineering process in highly populated test-beds is as important as the t...

  8. Environment exploration and SLAM experiment research based on ROS

    Science.gov (United States)

    Li, Zhize; Zheng, Wei

    2017-11-01

    Robots need to get the information of surrounding environment by means of map learning. SLAM or navigation based on mobile robots is developing rapidly. ROS (Robot Operating System) is widely used in the field of robots because of the convenient code reuse and open source. Numerous excellent algorithms of SLAM or navigation are ported to ROS package. hector_slam is one of them that can set up occupancy grid maps on-line fast with low computation resources requiring. Its characters above make the embedded handheld mapping system possible. Similarly, hector_navigation also does well in the navigation field. It can finish path planning and environment exploration by itself using only an environmental sensor. Combining hector_navigation with hector_slam can realize low cost environment exploration, path planning and slam at the same time

  9. Modeling Gene-Environment Interactions With Quasi-Natural Experiments.

    Science.gov (United States)

    Schmitz, Lauren; Conley, Dalton

    2017-02-01

    This overview develops new empirical models that can effectively document Gene × Environment (G×E) interactions in observational data. Current G×E studies are often unable to support causal inference because they use endogenous measures of the environment or fail to adequately address the nonrandom distribution of genes across environments, confounding estimates. Comprehensive measures of genetic variation are incorporated into quasi-natural experimental designs to exploit exogenous environmental shocks or isolate variation in environmental exposure to avoid potential confounders. In addition, we offer insights from population genetics that improve upon extant approaches to address problems from population stratification. Together, these tools offer a powerful way forward for G×E research on the origin and development of social inequality across the life course. © 2015 Wiley Periodicals, Inc.

  10. Flight Experiments for Living With a Star Space Environment Testbed (LWS-SET): Relationship to Technology

    Science.gov (United States)

    LaBel, Kenneth A.; Barth, Janet L.; Brewer, Dana A.

    2003-01-01

    This viewgraph presentation provides information on flight validation experiments for technologies to determine solar effects. The experiments are intended to demonstrate tolerance to a solar variant environment. The technologies tested are microelectronics, photonics, materials, and sensors.

  11. Managing Learning Experiences in an AACSB Environment: Beyond the Classroom

    Science.gov (United States)

    Spruell, James; Hawkins, Al; Vicknair, David

    2009-01-01

    The study explores the development and management of a rich learning environment that extends the traditional classroom to include significant co-curricular programs. Learning enrichment is guided by the individual mission of the business school, accreditation agency (AACSB), and in our case, the Jesuit mission. That central framework provides a…

  12. FOSS geospatial libraries in scientific workflow environments: experiences and directions

    CSIR Research Space (South Africa)

    McFerren, G

    2011-07-01

    Full Text Available of experiments. In context of three sets of research (wildfire research, flood modelling and the linking of disease outbreaks to multi-scale environmental conditions), we describe our efforts to provide geospatial capability for scientific workflow software...

  13. H12CN and H13CN excitation analysis in the circumstellar outflow of R Sculptoris

    Science.gov (United States)

    Saberi, M.; Maercker, M.; De Beck, E.; Vlemmings, W. H. T.; Olofsson, H.; Danilovich, T.

    2017-03-01

    Context. The 12CO/13CO isotopologue ratio in the circumstellar envelope (CSE) of asymptotic giant branch (AGB) stars has been extensively used as the tracer of the photospheric 12C/13C ratio. However, spatially-resolved ALMA observations of R Scl, a carbon rich AGB star, have shown that the 12CO/13CO ratio is not consistent over the entire CSE. Hence, it can not necessarily be used as a tracer of the 12C/13C ratio. The most likely hypothesis to explain the observed discrepancy between the 12CO/13CO and 12C/13C ratios is CO isotopologue selective photodissociation by UV radiation. Unlike the CO isotopologue ratio, the HCN isotopologue ratio is not affected by UV radiation. Therefore, HCN isotopologue ratios can be used as the tracer of the atomic C ratio in UV irradiated regions. Aims: We aim to present ALMA observations of H13CN(4-3) and APEX observations of H12CN(2-1), H13CN(2-1, 3-2) towards R Scl. These new data, combined with previously published observations, are used to determine abundances, ratio, and the sizes of line-emitting regions of the aforementioned HCN isotopologues. Methods: We have performed a detailed non-LTE excitation analysis of circumstellar H12CN(J = 1-0, 2-1, 3-2, 4-3) and H13CN(J = 2-1, 3-2, 4-3) line emission around R Scl using a radiative transfer code based on the accelerated lambda iteration (ALI) method. The spatial extent of the molecular distribution for both isotopologues is constrained based on the spatially resolved H13CN(4-3) ALMA observations. Results: We find fractional abundances of H12CN/H2 = (5.0 ± 2.0) × 10-5 and H13CN/H2 = (1.9 ± 0.4) × 10-6 in the inner wind (r ≤ (2.0 ± 0.25) ×1015 cm) of R Scl. The derived circumstellar isotopologue ratio of H12CN/H13CN = 26.3 ± 11.9 is consistent with the photospheric ratio of 12C/13C 19 ± 6. Conclusions: We show that the circumstellar H12CN/H13CN ratio traces the photospheric 12C/13C ratio. Hence, contrary to the 12CO/13CO ratio, the H12CN/H13CN ratio is not affected by UV

  14. Student perceptions of customer experience in a higher education environment

    Directory of Open Access Journals (Sweden)

    Albertus le Roux

    2014-11-01

    Research purpose: The main aim of the study was to measure students’ level of loyalty, advocacy intentions and perceptions of customer experience during service encounters with administrative staff of the North-West University. Motivation for the study: Positive experiences by students on-campus can increase their satisfaction levels which will lead to an increased propensity for further studies, develop a sense of loyalty and increase advocacy intentions to promote the university to others. Research approach, design and method: This quantitative research followed a descriptive research design. Self-administered questionnaires were handed out to 1295 students on the 3 campuses of the university. Main findings: Students on the Potchefstroom campus show much higher loyalty and advocacy intentions than their counterparts on the Vaal and Mafikeng campuses. Overall the findings indicate that the students have very positive perceptions of the professional appearance of staff members, and also think that their personal information is handled in a secure manner. Male and female students did not differ in their levels of customer experience. European language-speaking students reported a higher level of customer experience compared to their African language-speaking counterparts. The customer experience levels of students in the Potchefstroom Faculty of Health Sciences are higher than students in the Vaal Faculty of Humanities. Practical/managerial implications: It could be beneficial for the management of tertiary institutions to gain insight into the sources or factors that constitute positive experiences for students, for example convenient opening hours and ease of contacting staff by telephone. The training of newly appointed and existing staff could also be enhanced when they are sensitised regarding students’ perceptions of positive customer experiences. Contribution/value-add: The adoption of strategies by HEIs to attract and retain students and render excellent

  15. The chemistry in circumstellar envelopes of evolved stars: following the origin of the elements to the origin of life.

    Science.gov (United States)

    Ziurys, Lucy M

    2006-08-15

    Mass loss from evolved stars results in the formation of unusual chemical laboratories: circumstellar envelopes. Such envelopes are found around carbon- and oxygen-rich asymptotic giant branch stars and red supergiants. As the gaseous material of the envelope flows from the star, the resulting temperature and density gradients create a complex chemical environment involving hot, thermodynamically controlled synthesis, molecule "freeze-out," shock-initiated reactions, and photochemistry governed by radical mechanisms. In the circumstellar envelope of the carbon-rich star IRC+10216, >50 different chemical compounds have been identified, including such exotic species as C(8)H, C(3)S, SiC(3), and AlNC. The chemistry here is dominated by molecules containing long carbon chains, silicon, and metals such as magnesium, sodium, and aluminum, which makes it quite distinct from that found in molecular clouds. The molecular composition of the oxygen-rich counterparts is not nearly as well explored, although recent studies of VY Canis Majoris have resulted in the identification of HCO(+), SO(2), and even NaCl in this object, suggesting chemical complexity here as well. As these envelopes evolve into planetary nebulae with a hot, exposed central star, synthesis of molecular ions becomes important, as indicated by studies of NGC 7027. Numerous species such as HCO(+), HCN, and CCH are found in old planetary nebulae such as the Helix. This "survivor" molecular material may be linked to the variety of compounds found recently in diffuse clouds. Organic molecules in dense interstellar clouds may ultimately be traced back to carbon-rich fragments originally formed in circumstellar shells.

  16. Changing the Food Environment: The French Experience12

    OpenAIRE

    Chauliac, Michel; Hercberg, Serge

    2012-01-01

    The French National Nutrition and Health Program was launched in 2001. To achieve its objectives, 2 main preventive strategies were identified: 1) provide information and education to help individuals make healthy food and physical activity choices; and 2) improve the food and physical environment so that making healthy choices is easier. School regulations have been established to improve the nutritional quality of meals served to children and adolescents, and vending machines have been bann...

  17. Infrared observations of circumstellar ammonia in OH/IR supergiants

    Science.gov (United States)

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

    1980-01-01

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

  18. Infrared observations of circumstellar ammonia in OH/IR supergiants

    International Nuclear Information System (INIS)

    McLaren, R.A.; Betz, A.L.

    1980-01-01

    Ammonia has been detected in the circumstellar envelopes of VY Canis Majoris, VX Sagittarii, and IRC+10420 by means of several absorption lines in the ν 2 vibration-rotation band near 950 cm -1 . The line profiles are well resolved (0.2 km s -1 resolution) and show the gas being accelerated to terminal expansion velocities near 30 km s -1 . The observations reveal a method for determining the position of the central star on VLBI maps of OH maser emission to an accuracy of approx.0''.2. A firm lower limit of 2 x 10 15 cm -2 is obtained for the NH 3 column density in VY Canis Majoris

  19. Knowledge based instrumentation environment for future accelerator experiments

    International Nuclear Information System (INIS)

    Satyanarayana, B.

    1992-01-01

    Modern particle physics experiments are growing in complexity in terms of design and operation. Large scale accelerators producing very high energy particles are being employed, equipped with a variety of fine grain detectors to record the events. Main challenges in these experiments include: 1) Real-time supervision and fault diagnosis, 2)Trigger generation and monitoring, 3) Management of large volumes of event data, and 4) Track fitting and particle identification. The object of this paper is to propose artificial intelligence (AI) techniques to meet these challenges in an efficient way. Concepts are exemplified with the help of existing systems in this domain and new application areas in particle physics experiments are suggested for systems which are designed to work in different domains. (author). 11 refs

  20. Circumstellar grain extinction properties of recently discovered post AGB stars

    International Nuclear Information System (INIS)

    Buss, R.H. Jr.; Lamers, H.J.G.L.M.; Snow, T.P. Jr.

    1989-01-01

    The circumstellar grains of two hot evolved post asymptotic giant branch (post AGB) stars, HD 89353 and HD 213985 were examined. From ultraviolet spectra, energy balance of the flux, and Kurucz models, the extinction around 2175 A was derived. With visual spectra, an attempt was made to detect 6614 A diffuse band absorption arising from the circumstellar grains so that we could examine the relationship of these features to the infrared features. For both stars, we did not detect any diffuse band absorption at 6614 A, implying the carrier of this diffuse band is not the carrier of the unidentified infrared features not of the 2175 A bump. The linear ultraviolet extinction of the carbon-rich star HD 89353 was determined to continue across the 2175 A region with no sign of the bump; for HD 213985 it was found to be the reverse: a strong, wide bump in the mid-ultraviolet. The 213985 bump was found to be positioned at 2340 A, longward of its usual position in the interstellar medium. Since HD 213985 was determined to have excess carbon, the bump probably arises from a carbonaceous grain. Thus, in view of the ultraviolet and infrared properties of the two post AGB stars, ubiquitous interstellar infrared emission features do not seem to be associated with the 2175 A bump. Instead, the infrared features seem related to the linear ultraviolet extinction component: hydrocarbon grains of radius less than 300 A are present with the linear HD 89353 extinction; amorphous anhydrous carbonaceous grains of radius less than 50 A might cause the shifted ultraviolet extinction bump of HD 213985

  1. Grain Formation Processes in Oxygen-Rich Circumstellar Outflows: Testing the Metastable Eutectic Condensation Hypothesis and Measuring Atom-Grain & Grain-Grain Sticking Coefficients (A Sub-orbital Investigation)

    Science.gov (United States)

    Nuth, Joseph

    hypothesis would be a major step in establishing a simple, chemical kinetic model for the nucleation, growth and annealing of circumstellar oxide dust. Since strong convective flows in the terrestrial laboratory make it almost impossible to measure the growth and aggregation of freshly condensed, refractory grains, we will conduct experiments in microgravity to eliminate these flows. We propose to measure the efficiency of grain growth from simple SiO, AlO and FeO vapors and the sticking coefficients for dust coagulation via analyses of the grain morphology and size distribution of condensates collected and returned to earth during each rocket experiment. We will discuss the unique experimental systems used to produce our analog samples and the general nature of these materials. We note that these experimental systems were not designed to produce samples at equilibrium like typical petrologic systems. Indeed, they were designed to make samples that will help us to understand the properties of materials produced under highly dynamic conditions, quite far from equilibrium, that are often found in nature wherever steep temperature, pressure and/or compositional gradients result in highly unequilibrated solid systems. This design is an advantage as it presents the chance to compare and contrast samples produced at equilibrium with unequilibrated samples in order to identify distinctive traits that could be used to identify conditions under which natural samples have been formed. We will describe both the laboratory system and the rocket payload. We will present data from previous experiments in these systems and discuss why recovery of the flight payload and analyses of the particles produced is essential to build a rigorous, laboratory-based model of grain formation in astrophysical environments.

  2. Adult Student Expectations and Experiences in an Online Learning Environment

    Science.gov (United States)

    Bourdeaux, Renee; Schoenack, Lindsie

    2016-01-01

    This study investigated adult student experiences with instructors in online classes. Using expectancy violations theory as a lens, we conducted 22 interviews to understand reasons students enroll in online classes, expectations for instructors, and behaviors instructors employed that may or may not meet expectations. We conducted a thematic…

  3. The SWOOPE experience: Precollege students mapping the environment

    International Nuclear Information System (INIS)

    Eckhardt, R.C.; Hyer, D.K.

    1992-01-01

    SWOOPE (Students Watching Over Our Planet Earth) is an innovative environmental science education program for teachers and students sponsored by the Department of Energy and developed at the Los Alamos National Laboratory. The students, kindergarten through high school, gather data on an item of concern in the environment and send some of those data to a database at Los Alamos. Discussions and graphs of their results are sent back to them in newsletters. One of the key ideas of the program i s to involve the students in the process of science. They learn how to gather the data through a variety of hands-on science activities in the classroom and then take the measuring devices home to gather data in their own environment. Frequently, this involves their parents in the process as well. Although the measuring devices are usually simple and inexpensive, they are true scientific instruments, capable of gathering meaningful data. The collected data are available to scientists, agencies, and the community at large. Thus, the students participate in a truly collaborative scientific effort. Two SWOOPE Discovery Units, Water Quality and Radiation and Radon, were developed by teachers at summer institutes and have been piloted in the classroom over a two-year period. Currently, 112 teachers and almost 5000 students are using the materials. Data collected by students in the Radiation and Radon Unit include radon measurements and background measurements of ionizing radiation. The. student data on radon are being used b a study of home radon levels in New Mexico by the New Mexico Environment Department. Students in the Water Quality Unit are gathering data on city, ground and surface water that should also prove useful to environmental scientists. The water measurements include pH, temperature, turbidity, hardness, and the concentrations of nitrates, chlorine, and coliform bacteria

  4. Holding fast: the experience of collaboration in a competitive environment.

    Science.gov (United States)

    Fear, Heather; Barnett, Pauline

    2003-03-01

    Collaboration is one of the cornerstones of health promotion, with the literature indicating a range of circumstances under which it can either succeed or be undermined. In New Zealand in the 1990s, a market structure for health made collaboration of all kinds exceptionally difficult. This paper traces the efforts of a group of nutrition agencies (Agencies for Nutrition Action) to defy the popular wisdom and persist with collaborative efforts. The agencies were unsuccessful in their attempts to develop joint campaigns, but were very successful in advocacy and intersectoral action that did not threaten the position of individual agencies in the competitive environment. It is possible that the collaboration could have been more effective if agencies had been willing to surrender some autonomy and commit themselves to supporting a more independent new organization. However, this would have compromised not only their individual integrity but also their commitment to a relationship of equals. In 'holding fast' to a belief in health promotion, the ANA resisted being coopted by a now discredited market system, and emerged with its integrity and that of its participating agencies intact. ANA is now well positioned to work within an emerging policy environment that is more supportive of health promotion.

  5. Tracer experiment by using radioisotope in surface water environment

    International Nuclear Information System (INIS)

    Suh, K.S.; Kim, K.C.; Chun, I.Y.; Jung, S.H.; Lee, C.W.

    2007-01-01

    Complete text of publication follows. 1. Objective An expansion of industrial activities and urbanization result in still increasing amount of pollutants discharged into surface water. Discharged pollutants in surface water have harmful effects on the ecology of a river system and human beings. Pollutants discharged into surface water is transported and dispersed under conditions characteristic to particular natural water receiver. Radiotracer method is a useful tool for monitoring the pollutant dispersion and description of mixing process taking place in natural streams. A tracer experiment using radioisotope was carried out to investigate the characteristics of a pollutant transport and a determination of the diffusion coefficients in a river system. 2. Methods The upper area of the Keum river was selected for the tracer experiment, which is located in a mid west of Korea. The measurements of the velocity and bathymetry before a tracer experiment were performed to select the sampling lines for a detection of the radioisotope. The radioisotope was instantaneously injected into a flow as a point source by an underwater glass-vial crusher. The detection was made with 60 2inch NaI(Tl) scintillation detectors at 3 transverse lines at a downstream position. The multi-channel data acquisition systems were used to collect and process the signals transmitted from the detectors. Two-dimensional numerical models were used to simulate the hydraulic parameters and the concentration distributions of the radioisotope injected into the river. 3. Results and Conclusion The calculated results such as velocity and concentrations were compared with the measured ones. The dispersion characteristics of the radioisotope were analyzed according to a variation of the flow rate, water level and diffusion coefficients. Also, the diffusion coefficients were calculated by using the measured concentrations and the coefficients obtained from the field experiment were compared with the ones

  6. Greening the Danes? Experience with consumption and environment policies

    DEFF Research Database (Denmark)

    Christensen, Toke Haunstrup; Godskesen, Mirjam Irene; Gram-Hanssen, Kirsten

    2007-01-01

    structures, and information are all in accordance with each other, and this is only the case when sustainable consumption does not conflict with economic growth. A more fundamental critique thus concerns the failure of Danish consumer-oriented environmental policies to address consumption growth......Consumer-oriented environmental policies came high on the political agenda during the 1990s. Internationally, consumers were assigned a key role in environmental policies; also in Denmark, political initiatives were taken to promote sustainable consumer behaviour. In this article, the results...... of Danish policies related to consumption and environment are assessed by considering first, the environmental impacts of the political measures, and second, whether the policies have succeeded in addressing the dynamics behind increasing consumption. The study combines a theoretical understanding...

  7. A Regional Integrated Virtual Learning Environment: The AOU's Experience

    Directory of Open Access Journals (Sweden)

    Said Hammad

    2004-02-01

    Full Text Available In this paper we propose to construct a Regional Integrated Virtual Learning Environment (RIVLE for the Arab Open University (AOU. AOU is a new nonprofit learning institution with branches in six Arab countries and more branches scheduled to open in the near future. The university adopts an open learning methodology. We describe the major elements of the RIVLE and their interaction. We present a generic interface between the RIVLE and the Student Information System (SIS. We focus on the characteristics of the pedagogical model in the Arab Open University context and explain why RIVLE would be a perfect fit for this model. We argue that the potential benefits of a RIVLE are realized in such a setting. We also study the possibility of extending the RIVLE to existing learning institutions in the region.

  8. LHCb: Evaluation of the Radiation Environment of the LHCb Experiment

    CERN Multimedia

    Karacson, M

    2011-01-01

    The characterization of all aspects of the radiation field of the LHCb experiment is needed to understand the impact of the unprecedented radiation levels to which its detector and electronics are exposed to. The methodology on how this is done is described. Analysis of the measurements of active and passive sensors of various types which are distributed in and around the detector will be carried out. Appropriate cross calibrations will be applied and comparisons between them will be performed. Critical comparisons with simulation results obtained with the FLUKA Monte Carlo code are also an essential element of the study.

  9. EXTINCTION LAWS TOWARD STELLAR SOURCES WITHIN A DUSTY CIRCUMSTELLAR MEDIUM AND IMPLICATIONS FOR TYPE IA SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Nagao, Takashi; Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Nozawa, Takaya, E-mail: nagao@kusastro.kyoto-u.ac.jp [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2016-06-01

    Many astronomical objects are surrounded by dusty environments. In such dusty objects, multiple scattering processes of photons by circumstellar (CS) dust grains can effectively alter extinction properties. In this paper, we systematically investigate the effects of multiple scattering on extinction laws for steady-emission sources surrounded by the dusty CS medium using a radiation transfer simulation based on the Monte Carlo technique. In particular, we focus on whether and how the extinction properties are affected by properties of CS dust grains by adopting various dust grain models. We confirm that behaviors of the (effective) extinction laws are highly dependent on the properties of CS grains, especially the total-to-selective extinction ratio R{sub V}, which characterizes the extinction law and can be either increased or decreased and compared with the case without multiple scattering. We find that the criterion for this behavior is given by a ratio of albedos in the B and V bands. We also find that either small silicate grains or polycyclic aromatic hydrocarbons are necessary for realizing a low value of R{sub V} as often measured toward SNe Ia if the multiple scattering by CS dust is responsible for their non-standard extinction laws. Using the derived relations between the properties of dust grains and the resulting effective extinction laws, we propose that the extinction laws toward dusty objects could be used to constrain the properties of dust grains in CS environments.

  10. EXTINCTION LAWS TOWARD STELLAR SOURCES WITHIN A DUSTY CIRCUMSTELLAR MEDIUM AND IMPLICATIONS FOR TYPE IA SUPERNOVAE

    International Nuclear Information System (INIS)

    Nagao, Takashi; Maeda, Keiichi; Nozawa, Takaya

    2016-01-01

    Many astronomical objects are surrounded by dusty environments. In such dusty objects, multiple scattering processes of photons by circumstellar (CS) dust grains can effectively alter extinction properties. In this paper, we systematically investigate the effects of multiple scattering on extinction laws for steady-emission sources surrounded by the dusty CS medium using a radiation transfer simulation based on the Monte Carlo technique. In particular, we focus on whether and how the extinction properties are affected by properties of CS dust grains by adopting various dust grain models. We confirm that behaviors of the (effective) extinction laws are highly dependent on the properties of CS grains, especially the total-to-selective extinction ratio R V , which characterizes the extinction law and can be either increased or decreased and compared with the case without multiple scattering. We find that the criterion for this behavior is given by a ratio of albedos in the B and V bands. We also find that either small silicate grains or polycyclic aromatic hydrocarbons are necessary for realizing a low value of R V as often measured toward SNe Ia if the multiple scattering by CS dust is responsible for their non-standard extinction laws. Using the derived relations between the properties of dust grains and the resulting effective extinction laws, we propose that the extinction laws toward dusty objects could be used to constrain the properties of dust grains in CS environments.

  11. Generation of a Circumstellar Gas Disk by Hot Jupiter WASP-12b

    Science.gov (United States)

    Debrecht, Alex; Carroll-Nellenback, Jonathan; Frank, Adam; Fossati, Luca; Blackman, Eric G.; Dobbs-Dixon, Ian

    2018-05-01

    Observations of transiting extra-solar planets provide rich sources of data for probing the in-system environment. In the WASP-12 system, a broad depression in the usually-bright MgII h&k lines has been observed, in addition to atmospheric escape from the extremely hot Jupiter WASP-12b. It has been hypothesized that a translucent circumstellar cloud is formed by the outflow from the planet, causing the observed signatures. We perform 3D hydrodynamic simulations of the full system environment of WASP-12, injecting a planetary wind and stellar wind from their respective surfaces. We find that a torus of density high enough to account for the lack of MgII h&k line core emission in WASP-12 can be formed in approximately 13 years. We also perform synthetic observations of the Lyman-alpha spectrum at different points in the planet's orbit, which demonstrate that significant absorption occurs at all points in the orbit, not just during transits, as suggested by the observations.

  12. Dissociation of past and present experience in problem solving using a virtual environment.

    Science.gov (United States)

    Sturz, Bradley R; Bodily, Kent D; Katz, Jeffrey S

    2009-02-01

    An interactive 3D desktop virtual environment task was created to investigate learning mechanisms in human problem solving. Participants were assessed for previous video game experience, divided into two groups (Training and Control), and matched for gender and experience. The Training group learned specific skills within the virtual environment before being presented a problem. The Control group was presented the problem only. Completion time was faster for the Training group and was affected by level of previous video game experience. Results indicated problem solving was a function of specific and general experience and demonstrated a method for dissociating these two facets of experience.

  13. Observational constraints for the circumstellar disk of the B[e] star CPD-52 9243

    Science.gov (United States)

    Cidale, L. S.; Borges Fernandes, M.; Andruchow, I.; Arias, M. L.; Kraus, M.; Chesneau, O.; Kanaan, S.; Curé, M.; de Wit, W. J.; Muratore, M. F.

    2012-12-01

    Context. The formation and evolution of gas and dust environments around B[e] supergiants are still open issues. Aims: We intend to study the geometry, kinematics and physical structure of the circumstellar environment (CE) of the B[e] supergiant CPD-52 9243 to provide further insights into the underlying mechanism causing the B[e] phenomenon. Methods: The influence of the different physical mechanisms acting on the CE (radiation pressure, rotation, bi-stability or tidal forces) is somehow reflected in the shape and kinematic properties of the gas and dust regions (flaring, Keplerian, accretion or outflowing disks). To investigate these processes we mainly used quasi-simultaneous observations taken with high spatial resolution optical long-baseline interferometry (VLTI/MIDI), near-IR spectroscopy of CO bandhead features (Gemini/Phoenix and VLT/CRIRES) and optical spectra (CASLEO/REOSC). Results: High angular resolution interferometric measurements obtained with VLTI/MIDI provide strong support for the presence of a dusty disk(ring)-like structure around CPD-52 9243, with an upper limit for its inner edge of ~8 mas (~27.5 AU, considering a distance of 3.44 kpc to the star). The disk has an inclination angle with respect to the line of sight of 46 ± 7°. The study of CO first overtone bandhead evidences a disk structure in Keplerian rotation. The optical spectrum indicates a rapid outflow in the polar direction. Conclusions: The IR emission (CO and warm dust) indicates Keplerian rotation in a circumstellar disk while the optical line transitions of various species are consistent with a polar wind. Both structures appear simultaneously and provide further evidence for the proposed paradigms of the mass-loss in supergiant B[e] stars. The presence of a detached cold CO ring around CPD-52 9243 could be due to a truncation of the inner disk caused by a companion, located possibly interior to the disk rim, clearing the center of the system. More spectroscopic and

  14. New indoor environment chambers and field experiment offices for research on human comfort, health and productivity

    DEFF Research Database (Denmark)

    Toftum, Jørn; Langkilde, Gunnar; Fanger, Povl Ole

    2004-01-01

    The article describes three new indoor environment chambers, a new laboratory for the study of air movement in spaces and five offices for controlled environment exposures of human subjects in field experiments at the International Centre for Indoor Environment and Energy, Technical University of...... of Denmark. Together with three older chambers, the Centre now has at its disposal 12 spaces for studying indoor environments and their impact on human comfort, health and productivity.......The article describes three new indoor environment chambers, a new laboratory for the study of air movement in spaces and five offices for controlled environment exposures of human subjects in field experiments at the International Centre for Indoor Environment and Energy, Technical University...

  15. Experimenting with the virtual environment Moodle in Physics Education

    Science.gov (United States)

    Martins, Maria Ines; Dickman, Adriana

    2008-03-01

    The master's program in Physics Education of the Catholic University in the state of Minas Gerais, Brazil, includes the discipline ``Digital technologies in Physics education.'' The main goal of this discipline is to discuss the role of Information and Communication Technology (ICT) in the process of learning-teaching science. We introduce our students to several virtual platforms, both free and commercial, discussing their functionality and features. We encourage our students to get in touch with computer tools and resources by planning their own computer based course using the Moodle platform. We discuss different patterns of virtual environment courses, whose proposals are centered mainly in the students, or teacher-centered or even system-centered. The student is free to choose between only one topic and a year course to work with, since their interests vary from learning something more about a specific subject to a complete e-learning course covering the entire school year. (The courses are available online in the address sitesinf01.pucmg.br/moodle. Participation only requires filling out an application form.) After three editions of this discipline, we have several courses available. We realize that students tend to focus on traditional methods, always preserving their role as knowledge-givers. In conclusion, we can say that, in spite of exhaustive discussion about autonomy involved with ICTs abilities, most of the students used the new virtual medium to organize traditional teacher-centered courses.

  16. Remote Laboratory Experiments in a Virtual Immersive Learning Environment

    Directory of Open Access Journals (Sweden)

    Luca Berruti

    2008-01-01

    Full Text Available The Virtual Immersive Learning (VIL test bench implements a virtual collaborative immersive environment, capable of integrating natural contexts and typical gestures, which may occur during traditional lectures, enhanced with advanced experimental sessions. The system architecture is described, along with the motivations, and the most significant choices, both hardware and software, adopted for its implementation. The novelty of the approach essentially relies on its capability of embedding functionalities that stem from various research results (mainly carried out within the VICOM national project, and “putting the pieces together” in a well-integrated framework. These features, along with its high portability, good flexibility, and, above all, low cost, make this approach appropriate for educational and training purposes, mainly concerning measurements on telecommunication systems, at universities and research centers, as well as enterprises. Moreover, the methodology can be employed for remote access to and sharing of costly measurement equipment in many different activities. The immersive characteristics of the framework are illustrated, along with performance measurements related to a specific application.

  17. Experiences with a simulated learning environment - the SimuScape©: Virtual environments in medical education

    Directory of Open Access Journals (Sweden)

    Anna-Lena Thies

    2014-03-01

    Full Text Available INTRODUCTION: Simulation as a tool for medical education has gained considerable importance in the past years. Various studies have shown that the mastering of basic skills happens best if taught in a realistic and workplace-based context. It is necessary that simulation itself takes place in the realistic background of a genuine clinical or in an accordingly simulated learning environment. METHODS: A panoramic projection system that allows the simulation of different scenarios has been created at the medical school of the Westphalian Wilhelms-University  Muenster/Germany. The SimuScape© is a circular training room of six meters in diameter and has the capacity to generate pictures or moving images as well as the corresponding background noises for medical students, who are then able to interact with simulated patients inside a realistic environment. RESULTS: About 1,000 students have been instructed using the SimuScape© in the courses of emergency medicine, family medicine and anesthesia. The SimuScape©, with its 270°-panoramic projection, gives the students the impression “of being right in the center of action”.  It is a flexible learning environment that can be easily integrated into curricular teaching and which is in full operation for 10 days per semester. CONCLUSION: The SimuScape© allows the establishment of new medical areas outside the hospital and surgery for simulation and it is an extremely adaptable and cost-effective utilization of a lecture room. In this simulated environment it is possible to teach objectives like self-protection and patient care during disturbing environmental influences in practice.

  18. Circumstellar matter and the nature of the SN1987A progenitor star

    International Nuclear Information System (INIS)

    Chevalier, R.A.; Fransson, C.

    1987-01-01

    The radio observations of the supernova SN1987A can be interpreted in terms of its interaction with circumstellar matter. The early turn-on of the radio emission implies a relatively low density circumstellar medium. The optical properties of the supernova imply that the progenitor star had a smaller radius than that of a typical type II supernova progenitor. The mass loss properties are consistent with this hypothesis. The authors predict the thermal X-ray luminosity of the supernova, and note that it is below the current upper limit. A bright infrared dust echo is not expected. Weak ultraviolet emission lines from circumstellar gas may be visible. Although the circumstellar density is low, it is possible that the progenitor star did lose a substantial fraction of its mass prior to the supernova explosion. (author)

  19. Contribution to nuclear power stations to environment conservation (EDF experience)

    International Nuclear Information System (INIS)

    Astolfi, J.F.

    1993-01-01

    It is a world scale opinion now, that industrial activities, such as power generation, and energy use which still heavily rely on fossil fuels, are disproportionately instrumental in affecting our environment, and changing earth's physical conditions. For example, sulphur and nitrogen oxides, generated by coal and oil combustion, which can be harmful for our health, are also supposed to induce acid rains which damage our lakes and forests. Carbon dioxide emissions, which are unavoidable in most of combustion facilities, are acknowledged as instrumental in the open-quotes greenhouse effectclose quotes, which is supposed to bring about significant changes in the climate during forthcoming centuries. Facing such problems, severe regulations are now issued in most of industralized countries, mainly in the EEC, the aim of which is to reduce drastically pollutant discharge to the atmosphere. They obviously apply to power plants and as a consequence, utilities which operate fossil-fired units, will be prompted in the next future, to carry out sophisticated and expensive technical solutions to limitate pollutant emission to an acceptable level. In this respect, clean combustion technologies, such as fluidized beds, pollutant abatement systems such as flue gas desulphurization or denoxification, or even natural gas-fired plants like combined cycles, shall be designed and implemented, which will unavoidably increase the cost of power generation without totally solving the problem. In such a context, EDF opinion is that safe operation of nuclear power plants can make a substantial contribution in reducing pollution of the atmosphere, and this is highlighted by the example of the French nuclear program

  20. Interaction of NRCs with their environment - KAERI's experience

    International Nuclear Information System (INIS)

    Chang, In Soon

    2001-01-01

    Main players in KAERI's environment are the Government, nuclear industry (essentially nuclear power related), Academic community and the public. The Board of Trustees of KAERI has members from three important ministries of the Government and this Board formulates the nuclear R and D programme. The current programme plan covers a period of 1996-2006. The Korean nuclear industry has grown out of the core groups within KAERI. Until 1996, certain key areas in the design of nuclear steam supply system, nuclear fuel and nuclear waste management were still a part of KAERI responsibilities. However, with the growth of the nuclear power programme to 14 GW(e) (16 reactors), and more reactors under construction and plan, a decision has been taken to shift these activities to the industry, along with the personnel (600). The Government has also decided to secure financial resources for R and D by a contribution of 0.1 cents/kw·h from the nuclear utilities to a fund. In 1998 this fund collected 90 million US$ and 75% was made available to KAERI. So there is a very strong linkage between the Government, KAERI and the nuclear industry. With the academic community, KAERI takes post-graduate and post doctoral research students, gives R and D projects to the universities and has joint projects in some areas like fusion research. With public, KAERI has followed the policy of openness. It has made specific efforts to convey more easily understood benefits of radioisotopes and radiation. Also, communication is quite often targeted at specific groups rather than public at large. This policy has helped in the public acceptance of nuclear power which provided 41% of the electricity in 1998. (author)

  1. Circumstellar ammonia in oxygen-rich evolved stars

    Science.gov (United States)

    Wong, K. T.; Menten, K. M.; Kamiński, T.; Wyrowski, F.; Lacy, J. H.; Greathouse, T. K.

    2018-04-01

    Context. The circumstellar ammonia (NH3) chemistry in evolved stars is poorly understood. Previous observations and modelling showed that NH3 abundance in oxygen-rich stars is several orders of magnitude above that predicted by equilibrium chemistry. Aims: We would like to characterise the spatial distribution and excitation of NH3 in the oxygen-rich circumstellar envelopes (CSEs) of four diverse targets: IK Tau, VY CMa, OH 231.8+4.2, and IRC +10420. Methods: We observed NH3 emission from the ground state in the inversion transitions near 1.3 cm with the Very Large Array (VLA) and submillimetre rotational transitions with the Heterodyne Instrument for the Far-Infrared (HIFI) aboard Herschel Space Observatory from all four targets. For IK Tau and VY CMa, we observed NH3 rovibrational absorption lines in the ν2 band near 10.5 μm with the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility (IRTF). We also attempted to search for the rotational transition within the excited vibrational state (v2 = 1) near 2 mm with the IRAM 30m Telescope. Non-LTE radiative transfer modelling, including radiative pumping to the vibrational state, was carried out to derive the radial distribution of NH3 in the CSEs of these targets. Results: We detected NH3 inversion and rotational emission in all four targets. IK Tau and VY CMa show blueshifted absorption in the rovibrational spectra. We did not detect vibrationally excited rotational transition from IK Tau. Spatially resolved VLA images of IK Tau and IRC +10420 show clumpy emission structures; unresolved images of VY CMa and OH 231.8+4.2 indicate that the spatial-kinematic distribution of NH3 is similar to that of assorted molecules, such as SO and SO2, that exhibit localised and clumpy emission. Our modelling shows that the NH3 abundance relative to molecular hydrogen is generally of the order of 10-7, which is a few times lower than previous estimates that were made without considering radiative

  2. Classroom Assessment in Web-Based Instructional Environment: Instructors' Experience

    Directory of Open Access Journals (Sweden)

    Xin Liang

    2004-03-01

    Full Text Available While a great deal has been written on the advantage and benefits of online teaching, little is known on how..assessment is implemented in online classrooms to monitor and inform performance and progress. The..purpose of this study is to investigate the dynamics of WebCT classroom assessment by analyzing the..perceptions and experience of the instructors. Grounded theory method was employed to generate a - process..theory- . The study included 10 faculties who taught WebCT classes, and 216 students in the College of..Education in an urban university in the Mid west. Interviews and classroom observations were undertaken..on line. The findings indicated that, performance-based assessment, writing skills, interactive assessment..and learner autonomy were major assessment aspects to inform teaching and enhance learning. If one of..the major roles of online instruction is to increase self-directed learning, as part of the pedagogical..mechanism, web-based classroom assessment should be designed and practiced to impact learner autonomy.

  3. Guidelines to use tomato in experiments with a controlled environment.

    Directory of Open Access Journals (Sweden)

    Dietmar eSchwarz

    2014-11-01

    Full Text Available Domesticated tomato (Solanum lycopersicum is the most important horticultural crop worldwide. Low polymorphism at the DNA level conflicts with the wealth of morphological variation. Fruits vary widely in size, shape and colour. In contrast, genetic variation between the 16 wild relatives is tremendous. Several large seed banks provide tomato germplasm for both domesticated and wild accessions of tomato. Recently, the genomes of the inbred cultivar Heinz 1706 (≈900 Mb and S. pimpinellifolium (739 Mb were sequenced. Genomic markers and genome re-sequencing data are available for >150 cultivars and accessions. Transformation of tomato is relatively easy and T-DNA insertion line collections are available. Tomato is widely used as a model crop for fruit development but also for diverse physiological, cellular, biochemical, molecular and genetic studies. It can be easily grown in greenhouses or growth chambers. Plants grow, flower, and develop fruits well at daily light lengths between 8-16 hours. The required daily light integral of an experiment depends on growth stage and temperature investigated. Temperature must be 10-35°C, relative humidity 30-90 % and CO2 concentration 200-1500 µmol mol-1. Temperature determines the speed of the phenological development while daily light integral and CO2 concentration affect photosynthesis and biomass production. Seed to seed cultivation takes 100 days at 20°C and can be shortened or delayed by temperature. Tomato may be cultivated in soil, substrates, or aeroponically without any substrate. Root volume and water uptake requirements are primarily determined by transpiration demands of the plants. Many nutrient supply recipes and strategies are available to ensure sufficient supply as well as specific nutrient deficits/surplus. Using appropriate cultivation techniques makes tomato a convenient model plant for researchers, even for beginners.

  4. Guidelines to use tomato in experiments with a controlled environment

    Science.gov (United States)

    Schwarz, Dietmar; Thompson, Andrew J.; Kläring, Hans-Peter

    2014-01-01

    Domesticated tomato (Solanum lycopersicum) is the most important horticultural crop worldwide. Low polymorphism at the DNA level conflicts with the wealth of morphological variation. Fruits vary widely in size, shape, and color. In contrast, genetic variation between the 16 wild relatives is tremendous. Several large seed banks provide tomato germplasm for both domesticated and wild accessions of tomato. Recently, the genomes of the inbred cultivar “Heinz 1706” (≈900 Mb), and S. pimpinellifolium (739 Mb) were sequenced. Genomic markers and genome re-sequencing data are available for >150 cultivars and accessions. Transformation of tomato is relatively easy and T-DNA insertion line collections are available. Tomato is widely used as a model crop for fruit development but also for diverse physiological, cellular, biochemical, molecular, and genetic studies. It can be easily grown in greenhouses or growth chambers. Plants grow, flower, and develop fruits well at daily light lengths between 8 and 16 h. The required daily light integral of an experiment depends on growth stage and temperature investigated. Temperature must be 10–35°C, relative humidity 30–90%, and, CO2 concentration 200–1500 μmol mol−1. Temperature determines the speed of the phenological development while daily light integral and CO2 concentration affect photosynthesis and biomass production. Seed to seed cultivation takes 100 days at 20°C and can be shortened or delayed by temperature. Tomato may be cultivated in soil, substrates, or aeroponically without any substrate. Root volume, and water uptake requirements are primarily determined by transpiration demands of the plants. Many nutrient supply recipes and strategies are available to ensure sufficient supply as well as specific nutrient deficits/surplus. Using appropriate cultivation techniques makes tomato a convenient model plant for researchers, even for beginners. PMID:25477888

  5. Visualization environment for reviewing and experimenting with compaction equipment trajectories in context

    NARCIS (Netherlands)

    Vasenev, Alexandr; Hartmann, Timo; Miller, Seirgei Rosario; Doree, Andries G.

    Visualization Environments (VEs) can assist construction professionals in studying intricate interrelations between construction equipment trajectories and their context. Such VEs typically support them in either reviewing earlier conducted work or experimenting with possible alternatives. In the

  6. Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments.

    NARCIS (Netherlands)

    Dewiyanti, Silvia; Brand-Gruwel, Saskia; Jochems, Wim; Broers, Nick

    2008-01-01

    Dewiyanti, S., Brand-Gruwel, S., Jochems, W., & Broers, N. (2007). Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments. Computers in Human Behavior, 23, 496-514.

  7. EDUCATION REFORMS TOWARDS 21ST CENTURY SKILLS: TRANSFORMING STUDENTS' LEARNING EXPERIENCES THROUGH EFFECTIVE LEARNING ENVIRONMENTS

    OpenAIRE

    Harriet Wambui Njui

    2018-01-01

    This paper reviews literature on learning environments with a view to making recommendations on how teachers could create effective and high-quality learning environments that provide learners with transformative learning experiences as they go through the process of education. An effective learning environment is critical because quality education, which is essential to real learning and human development, is influenced by factors both inside and outside the classroom. Learning institutions ...

  8. Rapid disappearance of a warm, dusty circumstellar disk.

    Science.gov (United States)

    Melis, Carl; Zuckerman, B; Rhee, Joseph H; Song, Inseok; Murphy, Simon J; Bessell, Michael S

    2012-07-04

    Stars form with gaseous and dusty circumstellar envelopes, which rapidly settle into disks that eventually give rise to planetary systems. Understanding the process by which these disks evolve is paramount in developing an accurate theory of planet formation that can account for the variety of planetary systems discovered so far. The formation of Earth-like planets through collisional accumulation of rocky objects within a disk has mainly been explored in theoretical and computational work in which post-collision ejecta evolution typically is ignored, although recent work has considered the fate of such material. Here we report observations of a young, Sun-like star (TYC 8241 2652 1) where infrared flux from post-collisional ejecta has decreased drastically, by a factor of about 30, over a period of less than two years. The star seems to have gone from hosting substantial quantities of dusty ejecta, in a region analogous to where the rocky planets orbit in the Solar System, to retaining at most a meagre amount of cooler dust. Such a phase of rapid ejecta evolution has not been previously predicted or observed, and no currently available physical model satisfactorily explains the observations.

  9. Formation of polycyclic aromatic hydrocarbons in circumstellar envelopes

    International Nuclear Information System (INIS)

    Frenklach, M.; Feigelson, E.D.

    1989-01-01

    Production of polycyclic aromatic hydrocarbons in carbon-rich circumstellar envelopes was investigated using a kinetic approach. A detailed chemical reaction mechanism of gas-phase PAH formation and growth, containing approximately 100 reactions of 40 species, was numerically solved under the physical conditions expected in cool stellar winds. The chemistry is based on studies of soot production in hydrocarbon pyrolysis and combustion. Several first-ring and second-ring cyclization processes were considered. A linear lumping algorithm was used to describe PAH growth beyond the second aromatic ring. PAH production using this mechanism was examined with respect to a grid of idealized constant velocity stellar winds as well as several published astrophysical models. The basic result is that the onset of PAH production in the interstellar envelopes is predicted to occur within the temperature interval of 1100 to 900 K. The absolute amounts of the PAHs formed, however, are very sensitive to a number of parameters, both chemical and astrophysical, whose values are not accurately known. Astrophysically meaningful quantities of PAHs require particularly dense and slow stellar winds and high initial acetylene abundance. It is suggested that most of the PAHs may be produced in a relatively small fraction of carbon-rich red giants. 87 refs

  10. A WISE survey of circumstellar disks in Taurus

    International Nuclear Information System (INIS)

    Esplin, T. L.; Luhman, K. L.; Mamajek, E. E.

    2014-01-01

    We have compiled photometry at 3.4, 4.6, 12, and 22 μm from the all-sky survey performed by the Wide-field Infrared Survey Explorer (WISE) for all known members of the Taurus complex of dark clouds. Using these data and photometry from the Spitzer Space Telescope, we have identified members with infrared excess emission from circumstellar disks and have estimated the evolutionary stages of the detected disks, which include 31 new full disks and 16 new candidate transitional, evolved, evolved transitional, and debris disks. We have also used the WISE All-Sky Source Catalog to search for new disk-bearing members of Taurus based on their red infrared colors. Through optical and near-infrared spectroscopy, we have confirmed 26 new members with spectral types of M1-M7. The census of disk-bearing stars in Taurus should now be largely complete for spectral types earlier than ∼M8 (M ≳ 0.03 M ☉ ).

  11. A WISE survey of circumstellar disks in Taurus

    Energy Technology Data Exchange (ETDEWEB)

    Esplin, T. L.; Luhman, K. L. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Mamajek, E. E., E-mail: taran.esplin@psu.edu [Department of Physics and Astronomy, The University of Rochester, Rochester, NY 14627 (United States)

    2014-04-01

    We have compiled photometry at 3.4, 4.6, 12, and 22 μm from the all-sky survey performed by the Wide-field Infrared Survey Explorer (WISE) for all known members of the Taurus complex of dark clouds. Using these data and photometry from the Spitzer Space Telescope, we have identified members with infrared excess emission from circumstellar disks and have estimated the evolutionary stages of the detected disks, which include 31 new full disks and 16 new candidate transitional, evolved, evolved transitional, and debris disks. We have also used the WISE All-Sky Source Catalog to search for new disk-bearing members of Taurus based on their red infrared colors. Through optical and near-infrared spectroscopy, we have confirmed 26 new members with spectral types of M1-M7. The census of disk-bearing stars in Taurus should now be largely complete for spectral types earlier than ∼M8 (M ≳ 0.03 M {sub ☉}).

  12. RY Geminorum: an Algol binary with moderate circumstellar emission

    International Nuclear Information System (INIS)

    Hall, D.S.; Eaton, J.A.; Wilson, J.W.; Stuhlinger, T.

    1982-01-01

    RY Gem was observed extensively on the UBV system at two observatories over a period of 13 years. One new time of minimum, JD (Hel.) 2,444,215.490+-0.001 is derived, and a revised ephemeris for epochs since 1950: JD (Hel.)=2,439,732.6328+9sup(d).300567n is presented. Analyses carried out for both the Russell model and the Roche model give consistent values for the geometrical elements of the system: rsub(h)=r 1 =0.093+-0.001, rsub(c)=r 2 =0.2285+-0.0008, i=83 deg.5+-0 deg.2. For any reasonable value of the mass of the hotter component, the system consists of an early A-type star only slightly (Osup(m).5) above the main sequence and a cooler component having the surface temperature and gravity of a K1,3-K4,5 star. The most likely absolute dimensions of the components are M 1 =2.0+-03Msub(sun), R 1 =2.3+-0.1Rsub(sun) and M 2 =0.31+-0.06Msub(sun), R 2 =5.6+-0.2Rsub(sun). The effects of ring emission, which were removed from the observations before they were analyzed, seem to be typical of circumstellar emission in many other long-period Algol systems. (author)

  13. Young Stellar Variability of GM Cephei by Circumstellar Dust Clumps

    Science.gov (United States)

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

    2018-04-01

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

  14. THE MORPHOLOGY OF IRC+10420's CIRCUMSTELLAR EJECTA

    International Nuclear Information System (INIS)

    Tiffany, Chelsea; Humphreys, Roberta M.; Jones, Terry J.; Davidson, Kris

    2010-01-01

    Images of the circumstellar ejecta associated with the post-red supergiant IRC+10420 show a complex ejecta with visual evidence for episodic mass loss. In this paper, we describe the transverse motions of numerous knots, arcs, and condensations in the inner ejecta measured from second epoch Hubble Space Telescope/WFPC2 images. When combined with the radial motions for several of the features, the total space motion and direction of the outflows show that they were ejected at different times, in different directions, and presumably from separate regions on the surface of the star. These discrete structures in the ejecta are kinematically distinct from the general expansion of the nebula and their motions are dominated by their transverse velocities. They are apparently all moving within a few degrees of the plane of the sky. We are thus viewing IRC+10420 nearly pole-on and looking nearly directly down onto its equatorial plane. We also discuss the role of surface activity and magnetic fields on IRC+10420's recent mass-loss history.

  15. ALIGNMENT OF PROTOSTARS AND CIRCUMSTELLAR DISKS DURING THE EMBEDDED PHASE

    International Nuclear Information System (INIS)

    Spalding, Christopher; Batygin, Konstantin; Adams, Fred C.

    2014-01-01

    Star formation proceeds via the collapse of a molecular cloud core over multiple dynamical timescales. Turbulence within cores results in a spatially non-uniform angular momentum of the cloud, causing a stochastic variation in the orientation of the disk forming from the collapsing material. In the absence of star-disk angular momentum coupling, such disk-tilting would provide a natural mechanism for the production of primordial spin-orbit misalignments in the resulting planetary systems. However, owing to high accretion rates in the embedded phase of star formation, the inner edge of the circumstellar disk extends down to the stellar surface, resulting in efficient gravitational and accretional angular momentum transfer between the star and the disk. Here, we demonstrate that the resulting gravitational coupling is sufficient to suppress any significant star-disk misalignment, with accretion playing a secondary role. The joint tilting of the star-disk system leads to a stochastic wandering of star-aligned bipolar outflows. Such wandering widens the effective opening angle of stellar outflows, allowing for more efficient clearing of the remainder of the protostar's gaseous envelope. Accordingly, the processes described in this work provide an additional mechanism responsible for sculpting the stellar initial mass function

  16. EVIDENCE FOR ASYMMETRIC DISTRIBUTION OF CIRCUMSTELLAR MATERIAL AROUND TYPE Ia SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, Francisco; Gonzalez-Gaitan, Santiago; Anderson, Joseph; Marchi, Sebastian; Gutierrez, Claudia; Hamuy, Mario; Cartier, Regis [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Pignata, Giuliano [Departamento Ciencias Fisicas, Universidad Andres Bello, Av. Republica 252, Santiago (Chile)

    2012-08-01

    We study the properties of low-velocity material in the line of sight toward nearby Type Ia supernovae (SNe Ia) that have measured late phase nebular velocity shifts (v{sub neb}), thought to be an environment-independent observable. We have found that the distribution of equivalent widths of narrow blended Na I D1 and D2 and Ca II H and K absorption lines differs significantly between those SNe Ia with negative and positive v{sub neb}, with generally stronger absorption for SNe Ia with v{sub neb} {>=} 0. A similar result had been found previously for the distribution of colors of SNe Ia, which was interpreted as a dependence of the temperature of the ejecta with viewing angle. Our work suggests that (1) a significant part of these differences in color should be attributed to extinction, (2) this extinction is caused by an asymmetric distribution of circumstellar material (CSM), and (3) the CSM absorption is generally stronger on the side of the ejecta opposite to where the ignition occurs. Since it is difficult to explain (3) via any known physical processes that occur before explosion, we argue that the asymmetry of the CSM is originated after explosion by a stronger ionizing flux on the side of the ejecta where ignition occurs, probably due to a stronger shock breakout and/or more exposed radioactive material on one side of the ejecta. This result has important implications for both progenitor and explosion models.

  17. Pyrene synthesis in circumstellar envelopes and its role in the formation of 2D nanostructures

    Science.gov (United States)

    Zhao, Long; Kaiser, Ralf I.; Xu, Bo; Ablikim, Utuq; Ahmed, Musahid; Joshi, Dharati; Veber, Gregory; Fischer, Felix R.; Mebel, Alexander M.

    2018-05-01

    For the past decades, the hydrogen-abstraction/acetylene-addition (HACA) mechanism has been instrumental in attempting to untangle the origin of polycyclic aromatic hydrocarbons (PAHs) as identified in carbonaceous meteorites such as Allende and Murchison. However, the fundamental reaction mechanisms leading to the synthesis of PAHs beyond phenanthrene (C14H10) are still unknown. By exploring the reaction of the 4-phenanthrenyl radical (C14H9•) with acetylene (C2H2) under conditions prevalent in carbon-rich circumstellar environments, we show evidence of a facile, isomer-selective formation of pyrene (C16H10). Along with the hydrogen-abstraction/vinylacetylene-addition (HAVA) mechanism, molecular mass growth processes from pyrene may lead through systematic ring expansions not only to more complex PAHs, but ultimately to 2D graphene-type structures. These fundamental reaction mechanisms are crucial to facilitate an understanding of the origin and evolution of the molecular universe and, in particular, of carbon in our Galaxy.

  18. Home care nurses' experience of job stress and considerations for the work environment.

    Science.gov (United States)

    Samia, Linda W; Ellenbecker, Carol Hall; Friedman, Donna Haig; Dick, Karen

    2012-01-01

    Home care nurses report increased stress in their jobs due to work environment characteristics that impact professional practice. Stressors and characteristics of the professional practice environment that moderate nurses' experience of job stress were examined in this embedded multiple case study. Real life experiences within a complex environment were drawn from interviews and observations with 29 participants across two home care agencies from one eastern U.S. state. Findings suggest that role overload, role conflict, and lack of control can be moderated in agencies where there are meaningful opportunities for shared decision making and the nurse-patient relationship is supported.

  19. A Solid-State NMR Experiment: Analysis of Local Structural Environments in Phosphate Glasses

    Science.gov (United States)

    Anderson, Stanley E.; Saiki, David; Eckert, Hellmut; Meise-Gresch, Karin

    2004-01-01

    An experiment that can be used to directly study the local chemical environments of phosphorus in solid amorphous materials is demonstrated. The experiment aims at familiarizing the students of chemistry with the principles of solid-state NMR, by having them synthesize a simple phosphate glass, and making them observe the (super 31)P NMR spectrum,…

  20. Synchronous and Asynchronous Communication in an Online Environment: Faculty Experiences and Perceptions

    Science.gov (United States)

    Huang, Xiaoxia; Hsiao, E-Ling

    2012-01-01

    The purpose of this study was to examine online instructors' experiences and perceptions of online teaching and their communication with students in an online environment. More specifically, the study focused on the questions regarding: (1) instructors' general experiences and perceptions of online teaching; (2) instructors' general experiences…

  1. What Students Really Learn: Contrasting Medical and Nursing Students' Experiences of the Clinical Learning Environment

    Science.gov (United States)

    Liljedahl, Matilda; Boman, Lena Engqvist; Fält, Charlotte Porthén; Bolander Laksov, Klara

    2015-01-01

    This paper explores and contrasts undergraduate medical and nursing students' experiences of the clinical learning environment. Using a sociocultural perspective of learning and an interpretative approach, 15 in-depth interviews with medical and nursing students were analysed with content analysis. Students' experiences are described using a…

  2. Teacher Candidates' Experiences with Clinical Teaching in Reading Instruction: A Comparison between the Professional Development School Environment and the Non-Professional Development School Environment

    Science.gov (United States)

    Hopper, Cynthia J.

    2016-01-01

    Teacher candidates experience a variety of school settings when enrolled in teacher education methods courses. Candidates report varied experiences when in public school classrooms. This dissertation investigated clinical experiences of teacher candidates when placed in two different environments for clinical teaching. The two environments were a…

  3. ALMA OBSERVATIONS OF HD 141569’s CIRCUMSTELLAR DISK

    Energy Technology Data Exchange (ETDEWEB)

    White, J. A.; Boley, A. C. [Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Hughes, A. M.; Flaherty, K. M. [Department of Astronomy, Van Vleck Observatory, Wesleyan University, 96 Foss Hill Drive, Middletown, CT 06459 (United States); Ford, E. [Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802-2111 (United States); Wilner, D.; Payne, M. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Corder, S., E-mail: jawhite@astro.ubc.ca [North American ALMA Science Center, National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA, 22903 (United States)

    2016-09-20

    We present ALMA band 7 (345 GHz) continuum and {sup 12}CO( J = 3-2) observations of the circumstellar disk surrounding HD 141569. At an age of about 5 Myr, the disk has a complex morphology that may be best interpreted as a nascent debris system with gas. Our 870 μ m ALMA continuum observations resolve a dust disk out to approximately 56 au from the star (assuming a distance of 116 pc) with 0.″38 resolution and 0.07 mJy beam{sup −1} sensitivity. We measure a continuum flux density for this inner material of 3.8 ± 0.4 mJy (including calibration uncertainties). The {sup 12}CO(3-2) gas is resolved kinematically and spatially from about 30 to 210 au. The integrated {sup 12}CO(3-2) line flux density is 15.7 ± 1.6 Jy km s{sup −1}. We estimate the mass of the millimeter debris and {sup 12}CO(3-2) gas to be ≳0.04 M {sub ⊕} and ∼2 × 10{sup −3} M {sub ⊕}, respectively. If the millimeter grains are part of a collisional cascade, then we infer that the inner disk (<50 au) has ∼160 M {sub ⊕} contained within objects less than 50 km in radius, depending on the planetesimal size distribution and density assumptions. Markov Chain Monte Carlo modeling of the system reveals a disk morphology with an inclination of 53.°4 centered around an M = 2.39 M {sub ⊙} host star ( M sin( i ) = 1.92 M {sub ⊙}). We discuss whether the gas in HD 141569's disk may be second generation. If it is, the system can be used to study the clearing stages of planet formation.

  4. A qualitative exploration of chiropractic and physiotherapy teachers' experiences and conceptualizations of the educational environment

    Science.gov (United States)

    Palmgren, Per J.; Liljedahl, Matilda; Lindquist, Ingrid; Laksov, Klara Bolander

    2018-01-01

    Objective: There has been increasing scholarly interest in the role of environments in health care professional education, and the value of these has been widely acknowledged as an influential factor in educational quality. However, little is known about how teachers experience the environment, and there is a recognizable absence of a perspective from chiropractic and physiotherapy faculties. The aim of this study was to explore and contrast chiropractic and physiotherapy teachers' experiences and conceptualizations of the meaning of the educational environment. Methods: In this qualitative study, we performed semistructured interviews with 14 teachers, purposefully selected to obtain richness, variation, and breadth in the data. The data were analyzed using inductive qualitative content analysis. Results: The most noteworthy findings were, first, that chiropractic teachers experienced the meaning of the environment as motivating a vocational practice and modeling ideal, supporting and managing stressed students, and including students in the community of chiropractors. Physiotherapy teachers experienced the meaning of the environment as putting the pedagogical vision into practice, balancing students' expectations, and providing the prerequisites to grow within the profession. Second, both groups of teachers held common conceptualizations of the constituents of the environment as physical, organizational, relational, communicational, and pedagogical; however, they attached different connotations to these dimensions. Conclusion: The findings conveyed a variance in the experience of the meaning of the educational environment that can be attributed to contextual and cultural differences. PMID:29257707

  5. Grand-design Spiral Arms in a Young Forming Circumstellar Disk

    Energy Technology Data Exchange (ETDEWEB)

    Tomida, Kengo; Lin, Chia Hui [Department of Earth and Space Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Machida, Masahiro N. [Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan); Hosokawa, Takashi [Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Sakurai, Yuya, E-mail: tomida@vega.ess.sci.osaka-u.ac.jp [Department of Physics, The University of Tokyo, Tokyo 113-0033 (Japan)

    2017-01-20

    We study formation and long-term evolution of a circumstellar disk in a collapsing molecular cloud core using a resistive magnetohydrodynamic simulation. While the formed circumstellar disk is initially small, it grows as accretion continues, and its radius becomes as large as 200 au toward the end of the Class-I phase. A pair of grand-design spiral arms form due to gravitational instability in the disk, and they transfer angular momentum in the highly resistive disk. Although the spiral arms disappear in a few rotations as expected in a classical theory, new spiral arms form recurrently as the disk, soon becoming unstable again by gas accretion. Such recurrent spiral arms persist throughout the Class-0 and I phases. We then perform synthetic observations and compare our model with a recent high-resolution observation of a young stellar object Elias 2–27, whose circumstellar disk has grand-design spiral arms. We find good agreement between our theoretical model and the observation. Our model suggests that the grand-design spiral arms around Elias 2–27 are consistent with material arms formed by gravitational instability. If such spiral arms commonly exist in young circumstellar disks, it implies that young circumstellar disks are considerably massive and gravitational instability is the key process of angular momentum transport.

  6. Grand-design Spiral Arms in a Young Forming Circumstellar Disk

    International Nuclear Information System (INIS)

    Tomida, Kengo; Lin, Chia Hui; Machida, Masahiro N.; Hosokawa, Takashi; Sakurai, Yuya

    2017-01-01

    We study formation and long-term evolution of a circumstellar disk in a collapsing molecular cloud core using a resistive magnetohydrodynamic simulation. While the formed circumstellar disk is initially small, it grows as accretion continues, and its radius becomes as large as 200 au toward the end of the Class-I phase. A pair of grand-design spiral arms form due to gravitational instability in the disk, and they transfer angular momentum in the highly resistive disk. Although the spiral arms disappear in a few rotations as expected in a classical theory, new spiral arms form recurrently as the disk, soon becoming unstable again by gas accretion. Such recurrent spiral arms persist throughout the Class-0 and I phases. We then perform synthetic observations and compare our model with a recent high-resolution observation of a young stellar object Elias 2–27, whose circumstellar disk has grand-design spiral arms. We find good agreement between our theoretical model and the observation. Our model suggests that the grand-design spiral arms around Elias 2–27 are consistent with material arms formed by gravitational instability. If such spiral arms commonly exist in young circumstellar disks, it implies that young circumstellar disks are considerably massive and gravitational instability is the key process of angular momentum transport.

  7. No Evidence of Circumstellar Gas Surrounding Type Ia Supernova SN 2017cbv

    Science.gov (United States)

    Ferretti, Raphael; Amanullah, Rahman; Bulla, Mattia; Goobar, Ariel; Johansson, Joel; Lundqvist, Peter

    2017-12-01

    Nearby type Ia supernovae (SNe Ia), such as SN 2017cbv, are useful events to address the question of what the elusive progenitor systems of the explosions are. Hosseinzadeh et al. suggested that the early blue excess of the light curve of SN 2017cbv could be due to the supernova ejecta interacting with a non-degenerate companion star. Some SN Ia progenitor models suggest the existence of circumstellar (CS) environments in which strong outflows create low-density cavities of different radii. Matter deposited at the edges of the cavities should be at distances at which photoionization due to early ultraviolet (UV) radiation of SNe Ia causes detectable changes to the observable Na I D and Ca II H&K absorption lines. To study possible narrow absorption lines from such material, we obtained a time series of high-resolution spectra of SN 2017cbv at phases between ‑14.8 and +83 days with respect to B-band maximum, covering the time at which photoionization is predicted to occur. Both narrow Na I D and Ca II H&K are detected in all spectra, with no measurable changes between the epochs. We use photoionization models to rule out the presence of Na I and Ca II gas clouds along the line of sight of SN 2017cbv between ∼8 × 1016–2 × 1019 cm and ∼1015–1017 cm, respectively. Assuming typical abundances, the mass of a homogeneous spherical CS gas shell with radius R must be limited to {M}{{H} {{I}}}{CSM}R/{10}17[{cm}])}2 {M}ȯ . The bounds point to progenitor models that deposit little gas in their CS environment.

  8. INTERNATIONAL EXPERIENCE OF CLOUD ORIENTED LEARNING ENVIRONMENT DESIGN IN SECONDARY SCHOOLS

    Directory of Open Access Journals (Sweden)

    Svitlana G. Lytvynova

    2014-06-01

    Full Text Available The article highlights the foreign experience of designing of cloud oriented learning environments (COLE in general secondary education. The projects in Russia, Germany, Czech Republic, Australia, China, Israel, Africa, Singapore, Brazil, Egypt, Colombia and the United States are analyzed. The analysis of completed projects found out the common problems of implementing of cloud oriented learning environments (security of personal data, technical problems of integration of cloud environments with existing systems, and productivity of cloud services and their advantages for secondary education (mobility of participants, volumetric cloud data storage, universally accessibility, regular software updating, ease of use, etc..

  9. The impact of distraction in natural environments on user experience research

    DEFF Research Database (Denmark)

    Greifeneder, Elke

    2012-01-01

    Laboratories have long been seen as reasonable proxies for user experience research. Yet, this assumption may have become unreliable. The trend toward multiple activities in the users' natural environment, where people simultaneously use a digital library, join a chat or read an incoming Facebook....... The existence and impact of distraction is measured in a standard laboratory setting and in a remote setting that explicitly allows users to work in their own natural environment. The data indicates that there are significant differences between results from the laboratory and natural environment setting...

  10. Time Perception and the Experience of Time When Immersed in an Altered Sensory Environment.

    Science.gov (United States)

    Glicksohn, Joseph; Berkovich-Ohana, Aviva; Mauro, Federica; Ben-Soussan, Tal D

    2017-01-01

    The notion that exposure to a monotonous sensory environment could elicit reports indicating aberrant subjective experience and altered time perception is the impetus for the present report. Research has looked at the influence of exposure to such environments on time perception, reporting that the greater the environmental variation, the shorter is the time estimation obtained by the method of production. Most conditions for creating an altered sensory environment, however, have not facilitated an immersive experience, one that directly impacts both time perception and subjective experience. In this study, we invited our participants to enter a whole-body altered sensory environment for a 20-min session, wherein they were asked to relax without falling asleep. The session included white-colored illumination of the chamber with eyes closed (5 min), followed by 10 min of illuminating the room with color, after which a short report of subjective experience was collected using a brief questionnaire; this was followed by an additional 5 min of immersion in white light with closed eyes. The participants were then interviewed regarding their subjective experience, including their experience of time within the chamber. Prior to entering the chamber, the participants completed a time-production (TP) task. One group of participants then repeated the task within the chamber, at the end of the session; a second group of participants repeated the task after exiting the chamber. We shall report on changes in TP, and present data indicating that when produced time is plotted as a function of target duration, using a log-log plot, the major influence of sensory environment is on the intercept of the psychophysical function. We shall further present data indicating that for those participants reporting a marked change in time experience, such as "the sensation of time disappeared," their TP data could not be linearized using a log-log plot, hence indicating that for these

  11. Time Perception and the Experience of Time When Immersed in an Altered Sensory Environment

    Directory of Open Access Journals (Sweden)

    Joseph Glicksohn

    2017-10-01

    Full Text Available The notion that exposure to a monotonous sensory environment could elicit reports indicating aberrant subjective experience and altered time perception is the impetus for the present report. Research has looked at the influence of exposure to such environments on time perception, reporting that the greater the environmental variation, the shorter is the time estimation obtained by the method of production. Most conditions for creating an altered sensory environment, however, have not facilitated an immersive experience, one that directly impacts both time perception and subjective experience. In this study, we invited our participants to enter a whole-body altered sensory environment for a 20-min session, wherein they were asked to relax without falling asleep. The session included white-colored illumination of the chamber with eyes closed (5 min, followed by 10 min of illuminating the room with color, after which a short report of subjective experience was collected using a brief questionnaire; this was followed by an additional 5 min of immersion in white light with closed eyes. The participants were then interviewed regarding their subjective experience, including their experience of time within the chamber. Prior to entering the chamber, the participants completed a time-production (TP task. One group of participants then repeated the task within the chamber, at the end of the session; a second group of participants repeated the task after exiting the chamber. We shall report on changes in TP, and present data indicating that when produced time is plotted as a function of target duration, using a log–log plot, the major influence of sensory environment is on the intercept of the psychophysical function. We shall further present data indicating that for those participants reporting a marked change in time experience, such as “the sensation of time disappeared,” their TP data could not be linearized using a log–log plot, hence

  12. Automation and Control Learning Environment with Mixed Reality Remote Experiments Architecture

    Directory of Open Access Journals (Sweden)

    Frederico M. Schaf

    2007-05-01

    Full Text Available This work aims to the use of remotely web-based experiments to improve the learning process of automation and control systems theory courses. An architecture combining virtual learning environments, remote experiments, students guide and experiments analysis is proposed based on a wide state of art study. The validation of the architecture uses state of art technologies and new simple developed programs to implement the case studies presented. All implementations presented use an internet accessible virtual learning environment providing educational resources, guides and learning material to create a distance learning course associated with the remote mixed reality experiment. This work is part of the RExNet consortium, supported by the European Alfa project.

  13. Towards understanding experiences of women aspiring to senior management positions within a business environment

    OpenAIRE

    2012-01-01

    D.Phil. Equality, status and remuneration of women in the workforce remain of on-going interest and concern. Although extensive research has been conducted into this field, intensely personal experiences of women in the work environment is an important area to be researched, as this may hold the key to assisting them in successfully reaching the higher echelons within the business world. Insight into women’s workplace experiences is a worldwide need in order to improve empowerment and equa...

  14. The SAMPLE experience: The development of a rich media online mathematics learning environment

    OpenAIRE

    Chang, Jen

    2006-01-01

    This report documents the development of Sample Architecture for Mathematically Productive Learning Experiences (SAMPLE), a rich media, online, mathematics learning environment created to meet the needs of middle school educators. It explores some of the current pedagogical challenges in mathematics education, and their amplified impacts when coupled with under-prepared teachers, a decidedly wide-spread phenomenon. The SAMPLE publishing experience is discussed in terms of its instructional de...

  15. Measuring the Customer Experience in Online Environments: A Structural Modeling Approach

    OpenAIRE

    Thomas P. Novak; Donna L. Hoffman; Yiu-Fai Yung

    2000-01-01

    Intuition and previous research suggest that creating a compelling online environment for Web consumers will have numerous positive consequences for commercial Web providers. Online executives note that creating a compelling online experience for cyber customers is critical to creating competitive advantage on the Internet. Yet, very little is known about the factors that make using the Web a compelling experience for its users, and of the key consumer behavior outcomes of this compelling exp...

  16. Sensorimotor body-environment interaction serves to regulate emotional experience and exploratory behavior

    Directory of Open Access Journals (Sweden)

    Martin Dobricki

    2016-10-01

    Full Text Available Almost all living species regularly explore environments that they experience as pleasant, aversive, arousing or frightening. We postulate that such exploratory behavior and emotional experience both are regulated based on the interdependent perception of one’s body and stimuli that collectively define a spatial context such as a cliff. Here we examined this by testing if the interaction of the sensory input on one’s gait and the sensory input on the spatial context is modulating both the emotional experience of the environment and its exploration through head motion. To this end, we asked healthy humans to explore a life-sized Virtual Reality simulation of a forest glade by physically walking around in this environment on two narrow rectangular platforms connected by a plank. The platforms and the plank were presented such that they were either placed on ground or on the top of two high bridge piers. Hence, the forest glade was presented either as a “ground” or as a “height” context. Within these two spatial contexts the virtual plank was projected either on the rigid physical floor or onto a bouncy physical plank. Accordingly, the gait of our participants while they crossed the virtual plank was either “smooth” or “bouncy.” We found that in the height context bouncy gait compared to smooth gait increased the orientation of the head below the horizon and intensified the experience of the environment as negative. Whereas, within the ground context bouncy gait increased the orientation of the head towards and above the horizon and made that the environment was experienced as positive. Our findings suggest that the brain of healthy humans is using the interaction of the sensory input on their gait and the sensory input on the spatial context to regulate both the emotional experience of the environment and its exploration through head motion. Keywords: Neuroscience, Psychology

  17. Spectral Evidence for an Inner Carbon-rich Circumstellar Belt in the Young HD 36546 A-star System

    Energy Technology Data Exchange (ETDEWEB)

    Lisse, C. M. [JHU-APL, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Sitko, M. L. [Department of Physics, University of Cincinnati, Cincinnati, OH 45221-0011 and Space Science Institute, Boulder, CO 80301 (United States); Russell, R. W. [The Aerospace Corporation, Los Angeles, CA 90009 (United States); Marengo, M. [Department of Physics and Astronomy, 12 Physics Hall, Iowa State University, Ames, IA 50010 (United States); Currie, T. [Subaru Telescope, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, Hilo, HI 96720 (United States); Melis, C. [Center for Astrophysics and Space Sciences, University of California, San Diego, CA 92093-0424 (United States); Mittal, T. [Department of Earth and Planetary Sciences, McCone Hall, University of California at Berkeley, Berkeley, CA 94720 (United States); Song, I., E-mail: carey.lisse@jhuapl.edu, E-mail: ron.vervack@jhuapl.edu, E-mail: sitkoml@ucmail.uc.edu, E-mail: ray.russell@aero.org, E-mail: mmarengo@iastate.edu, E-mail: currie@naoj.org, E-mail: cmelis@ucsd.edu, E-mail: tmittal2@berkeley.edu, E-mail: song@physast.uga.edu [Department of Physics and Astronomy, University of Georgia, Athens, GA 30602-2451 (United States)

    2017-05-10

    Using the NASA/IRTF SpeX and BASS spectrometers we have obtained 0.7–13 μ m observations of the newly imaged 3–10 Myr old HD 36546 disk system. The SpeX spectrum is most consistent with the photospheric emission expected from an L {sub *} ∼ 20 L {sub ⊙}, solar abundance A1.5V star with little to no extinction, and excess emission from circumstellar dust detectable beyond 4.5 μ m. Non-detections of CO emission lines and accretion signatures point to the gas-poor circumstellar environment of a very old transition disk. Combining the SpeX + BASS spectra with archival WISE / AKARI / IRAS / Herschel photometry, we find an outer cold dust belt at ∼135 K and 20–40 au from the primary, likely coincident with the disk imaged by Subaru, and a new second inner belt with a temperature ∼570 K and an unusual, broad SED maximum in the 6–9 μ m region, tracing dust at 1.1–2.2 au. An SED maximum at 6–9 μ m has been reported in just two other A-star systems, HD 131488 and HD 121191, both of ∼10 Myr age. From Spitzer , we have also identified the ∼12 Myr old A7V HD 148657 system as having similar 5–35 μ m excess spectral features. The Spitzer data allows us to rule out water emission and rule in carbonaceous materials—organics, carbonates, SiC—as the source of the 6–9 μ m excess. Assuming a common origin for the four young A-star systems’ disks, we suggest they are experiencing an early era of carbon-rich planetesimal processing.

  18. METAMORPHOSIS OF SN 2014C: DELAYED INTERACTION BETWEEN A HYDROGEN POOR CORE-COLLAPSE SUPERNOVA AND A NEARBY CIRCUMSTELLAR SHELL

    International Nuclear Information System (INIS)

    Milisavljevic, D.; Margutti, R.; Kamble, A.; Patnaude, D. J.; Raymond, J. C.; Challis, P.; Drout, M. R.; Grindlay, J. E.; Kirshner, R. P.; Lunnan, R.; Miller, G. F.; Parrent, J. T.; Sanders, N. E.; Eldridge, J. J.; Fong, W.; Bietenholz, M.; Chornock, R.; Fransson, C.; Fesen, R. A.; Mackey, J.

    2015-01-01

    We present optical observations of supernova SN 2014C, which underwent an unprecedented slow metamorphosis from H-poor type Ib to H-rich type IIn over the course of one year. The observed spectroscopic evolution is consistent with the supernova having exploded in a cavity before encountering a massive shell of the progenitor star’s stripped hydrogen envelope. Possible origins for the circumstellar shell include a brief Wolf–Rayet fast wind phase that overtook a slower red supergiant wind, eruptive ejection, or confinement of circumstellar material by external influences of neighboring stars. An extended high velocity Hα absorption feature seen in near-maximum light spectra implies that the progenitor star was not completely stripped of hydrogen at the time of core collapse. Archival pre-explosion Subaru Telescope Suprime-Cam and Hubble Space Telescope Wide Field Planetary Camera 2 images of the region obtained in 2009 show a coincident source that is most likely a compact massive star cluster in NGC 7331 that hosted the progenitor system. By comparing the emission properties of the source with stellar population models that incorporate interacting binary stars we estimate the age of the host cluster to be 30–300 Myr, and favor ages closer to 30 Myr in light of relatively strong Hα emission. SN 2014C is the best observed member of a class of core-collapse supernovae that fill the gap between events that interact strongly with dense, nearby environments immediately after explosion and those that never show signs of interaction. Better understanding of the frequency and nature of this intermediate population can contribute valuable information about the poorly understood final stages of stellar evolution

  19. METAMORPHOSIS OF SN 2014C: DELAYED INTERACTION BETWEEN A HYDROGEN POOR CORE-COLLAPSE SUPERNOVA AND A NEARBY CIRCUMSTELLAR SHELL

    Energy Technology Data Exchange (ETDEWEB)

    Milisavljevic, D.; Margutti, R.; Kamble, A.; Patnaude, D. J.; Raymond, J. C.; Challis, P.; Drout, M. R.; Grindlay, J. E.; Kirshner, R. P.; Lunnan, R.; Miller, G. F.; Parrent, J. T.; Sanders, N. E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, 02138 (United States); Eldridge, J. J. [Department of Physics, University of Auckland, Private Bag 92019, Auckland (New Zealand); Fong, W. [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Bietenholz, M. [Hartebeesthoek Radio Observatory, P.O. Box 443, Krugersdorp 1740 (South Africa); Chornock, R. [Astrophysical Institute, Department of Physics and Astronomy, 251B Clippinger Lab, Ohio University, Athens, OH 45701 (United States); Fransson, C. [Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE106 91 Stockholm (Sweden); Fesen, R. A. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Lab, Hanover, NH 03755 (United States); Mackey, J., E-mail: dmilisav@cfa.harvard.edu [Argelander-Institut für Astronomie, Auf dem Hgel 71, D-53121 Bonn (Germany); and others

    2015-12-20

    We present optical observations of supernova SN 2014C, which underwent an unprecedented slow metamorphosis from H-poor type Ib to H-rich type IIn over the course of one year. The observed spectroscopic evolution is consistent with the supernova having exploded in a cavity before encountering a massive shell of the progenitor star’s stripped hydrogen envelope. Possible origins for the circumstellar shell include a brief Wolf–Rayet fast wind phase that overtook a slower red supergiant wind, eruptive ejection, or confinement of circumstellar material by external influences of neighboring stars. An extended high velocity Hα absorption feature seen in near-maximum light spectra implies that the progenitor star was not completely stripped of hydrogen at the time of core collapse. Archival pre-explosion Subaru Telescope Suprime-Cam and Hubble Space Telescope Wide Field Planetary Camera 2 images of the region obtained in 2009 show a coincident source that is most likely a compact massive star cluster in NGC 7331 that hosted the progenitor system. By comparing the emission properties of the source with stellar population models that incorporate interacting binary stars we estimate the age of the host cluster to be 30–300 Myr, and favor ages closer to 30 Myr in light of relatively strong Hα emission. SN 2014C is the best observed member of a class of core-collapse supernovae that fill the gap between events that interact strongly with dense, nearby environments immediately after explosion and those that never show signs of interaction. Better understanding of the frequency and nature of this intermediate population can contribute valuable information about the poorly understood final stages of stellar evolution.

  20. Environment

    DEFF Research Database (Denmark)

    Valentini, Chiara

    2017-01-01

    The term environment refers to the internal and external context in which organizations operate. For some scholars, environment is defined as an arrangement of political, economic, social and cultural factors existing in a given context that have an impact on organizational processes and structures....... For others, environment is a generic term describing a large variety of stakeholders and how these interact and act upon organizations. Organizations and their environment are mutually interdependent and organizational communications are highly affected by the environment. This entry examines the origin...... and development of organization-environment interdependence, the nature of the concept of environment and its relevance for communication scholarships and activities....

  1. Narratives from the Online Frontier: A K-12 Student's Experience in an Online Learning Environment

    Science.gov (United States)

    Barbour, Michael; Siko, Jason; Sumara, JaCinda; Simuel-Everage, Kaye

    2012-01-01

    Despite a large increase in the number of students enrolled in online courses, published research on student experiences in these environments is minimal. This article reports the narrative analysis of a series of interviews conducted with a female student at a brick-and-mortar school enrolled in a single virtual school course. Her narratives…

  2. The Context of Child Care for Toddlers: The "Experience Expectable Environment"

    Science.gov (United States)

    La Paro, Karen M.; Gloeckler, Lissy

    2016-01-01

    An experience expectable environment in child care classrooms is one in which teachers consistently provide positive and nurturing interactions within daily routines and activities to enhance children's learning. Growing numbers of children are being enrolled in child care at earlier ages and staying for longer periods of time each day which is…

  3. Nursing Faculty Experiences of Virtual Learning Environments for Teaching Clinical Reasoning

    Science.gov (United States)

    Zacharzuk-Marciano, Tara

    2017-01-01

    Nurses need sharp, clinical reasoning skills to respond to critical situations and to be successful at work in a complex and challenging healthcare system. While past research has focused on using virtual learning environments to teach clinical reasoning, there has been limited research on the experiences of nursing faculty and there is a need for…

  4. Virtual Learning Environments and Learning Forms -experiments in ICT-based learning

    DEFF Research Database (Denmark)

    Helbo, Jan; Knudsen, Morten

    2004-01-01

    This paper report the main results of a three year experiment in ICT-based distance learning. The results are based on a full scale experiment in the education, Master of Industrial Information Technology (MII) and is one of many projects deeply rooted in the project Virtual Learning Environments...... didactic model has until now been a positive experience........ The main problem is that we do not find the same self regulatoring learning effect in the group work among the off-campus students as is the case for on-campus students. Based on feedback from evaluation questionnaires and discussions with the students didactic adjustments have been made. The revised...

  5. Facilitative and obstructive factors in the clinical learning environment: Experiences of pupil enrolled nurses

    Directory of Open Access Journals (Sweden)

    Eucebious Lekalakala-Mokgele

    2015-03-01

    Full Text Available Background: The clinical learning environment is a complex social entity that influences student learning outcomes in the clinical setting. Students can experience the clinical learning environment as being both facilitative and obstructive to their learning. The clinical environment may be a source of stress, creating feelings of fear and anxiety which in turn affect the students’ responses to learning. Equally, the environment can enhance learning if experienced positively. Objectives: This study described pupil enrolled nurses’ experiences of facilitative and obstructive factors in military and public health clinical learning settings. Method: Using a qualitative, contextual, exploratory descriptive design, three focus group interviews were conducted until data saturation was reached amongst pupil enrolled nurses in a military School of Nursing. Results: Data analysed provided evidence that acceptance by clinical staff and affordance of self-directed learning facilitated learning. Students felt safe to practise when they were supported by the clinical staff. They felt a sense of belonging when the staff showed an interest in and welcomed them. Learning was obstructed when students were met with condescending comments. Wearing of a military uniform in the public hospital and horizontal violence obstructed learning in the clinical learning environment. Conclusion: Students cannot have effective clinical preparation if the environment is not conducive to and supportive of clinical learning, The study shows that military nursing students experience unique challenges as they are trained in two professions that are hierarchical in nature. The students experienced both facilitating and obstructing factors to their learning during their clinical practice. Clinical staff should be made aware of factors which can impact on students’ learning. Policies need to be developed for supporting students in the clinical learning

  6. Facilitative and obstructive factors in the clinical learning environment: Experiences of pupil enrolled nurses.

    Science.gov (United States)

    Lekalakala-Mokgele, Eucebious; Caka, Ernestine M

    2015-03-31

    The clinical learning environment is a complex social entity that influences student learning outcomes in the clinical setting. Students can experience the clinical learning environment as being both facilitative and obstructive to their learning. The clinical environment may be a source of stress, creating feelings of fear and anxiety which in turn affect the students' responses to learning. Equally, the environment can enhance learning if experienced positively. This study described pupil enrolled nurses' experiences of facilitative and obstructive factors in military and public health clinical learning settings. Using a qualitative, contextual, exploratory descriptive design, three focus group interviews were conducted until data saturation was reached amongst pupil enrolled nurses in a military School of Nursing. Data analysed provided evidence that acceptance by clinical staff and affordance of self-directed learning facilitated learning. Students felt safe to practise when they were supported by the clinical staff. They felt a sense of belonging when the staff showed an interest in and welcomed them. Learning was obstructed when students were met with condescending comments. Wearing of a military uniform in the public hospital and horizontal violence obstructed learning in the clinical learning environment. Students cannot have effective clinical preparation if the environment is not conducive to and supportive of clinical learning, The study shows that military nursing students experience unique challenges as they are trained in two professions that are hierarchical in nature. The students experienced both facilitating and obstructing factors to their learning during their clinical practice. Clinical staff should be made aware of factors which can impact on students' learning. Policies need to be developed for supporting students in the clinical learning environment.

  7. NASA Virtual Glovebox: An Immersive Virtual Desktop Environment for Training Astronauts in Life Science Experiments

    Science.gov (United States)

    Twombly, I. Alexander; Smith, Jeffrey; Bruyns, Cynthia; Montgomery, Kevin; Boyle, Richard

    2003-01-01

    The International Space Station will soon provide an unparalleled research facility for studying the near- and longer-term effects of microgravity on living systems. Using the Space Station Glovebox Facility - a compact, fully contained reach-in environment - astronauts will conduct technically challenging life sciences experiments. Virtual environment technologies are being developed at NASA Ames Research Center to help realize the scientific potential of this unique resource by facilitating the experimental hardware and protocol designs and by assisting the astronauts in training. The Virtual GloveboX (VGX) integrates high-fidelity graphics, force-feedback devices and real- time computer simulation engines to achieve an immersive training environment. Here, we describe the prototype VGX system, the distributed processing architecture used in the simulation environment, and modifications to the visualization pipeline required to accommodate the display configuration.

  8. THE VIRTUAL LEARNING ENVIRONMENTS IN VOCATIONAL EDUCATION: A REPORT OF BLENDED LEARNING EXPERIENCES

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Prado Constantino

    2013-07-01

    Full Text Available This paper presents an experiment in uses of virtual learning environments (VLE in the vocational education, evaluated by the Educational Supervision of Vocational and Secondary Schools of Paula Souza Center. The experience occurred in Etec "Jacinto Ferreira de Sá", São Paulo, Brazil, between 2009 and 2011, where the reported activities were organized and developed in the degree of Music, with students of different ages. Using specifics instruments to qualitative research for data collection were selected class record books, the reports to the virtual environment, the records of the participants' personal reflections, interviews and examination of the minutes of class councils involved. The experience has served as a basis for replication in other contexts and vocational courses presented by the institution.

  9. What students really learn: contrasting medical and nursing students' experiences of the clinical learning environment.

    Science.gov (United States)

    Liljedahl, Matilda; Boman, Lena Engqvist; Fält, Charlotte Porthén; Bolander Laksov, Klara

    2015-08-01

    This paper explores and contrasts undergraduate medical and nursing students' experiences of the clinical learning environment. Using a sociocultural perspective of learning and an interpretative approach, 15 in-depth interviews with medical and nursing students were analysed with content analysis. Students' experiences are described using a framework of 'before', 'during' and 'after' clinical placements. Three major themes emerged from the analysis, contrasting the medical and nursing students' experiences of the clinical learning environment: (1) expectations of the placement; (2) relationship with the supervisor; and (3) focus of learning. The findings offer an increased understanding of how medical and nursing students learn in the clinical setting; they also show that the clinical learning environment contributes to the socialisation process of students not only into their future profession, but also into their role as learners. Differences between the two professions should be taken into consideration when designing interprofessional learning activities. Also, the findings can be used as a tool for clinical supervisors in the reflection on how student learning in the clinical learning environment can be improved.

  10. Focusing on the Environment to Improve Youth Participation: Experiences and Perspectives of Occupational Therapists.

    Science.gov (United States)

    Anaby, Dana; Law, Mary; Teplicky, Rachel; Turner, Laura

    2015-10-23

    The environment plays a key role in supporting children's participation and can serve as a focus of intervention. This study aimed to elicit the perceptions and experiences of occupational therapists who had applied the PREP approach--Pathways and Resources for Engagement and Participation. PREP is a novel 12-week intervention for youth with physical disabilities, aimed at improving participation in leisure community-based activities by modifying aspects of the environment. Using a qualitative post-intervention only design, 12 therapists took part in individual semi-structured interviews, in which the therapists reflected on their experience using PREP to enable participation. A thematic analysis was conducted. Four themes emerged from the data; two of which were informative in nature, describing elements of the PREP intervention that target multi-layered composition of the environment and use strategies that involve leveraging resources and problem solving. The two remaining themes were reflective in nature, illustrating a new take on the Occupational Therapy role and re-positioning the concept of participation in therapy practices. Results emphasize aspects of the environment that can serve as effective targets of intervention, guided by the PREP approach. Findings can broaden the scope and focus of occupational therapy practice by redefining views on participation and the environment.

  11. Evaluation for the design of experience in virtual environments: modeling breakdown of interaction and illusion.

    Science.gov (United States)

    Marsh, T; Wright, P; Smith, S

    2001-04-01

    New and emerging media technologies have the potential to induce a variety of experiences in users. In this paper, it is argued that the inducement of experience presupposes that users are absorbed in the illusion created by these media. Looking to another successful visual medium, film, this paper borrows from the techniques used in "shaping experience" to hold spectators' attention in the illusion of film, and identifies what breaks the illusion/experience for spectators. This paper focuses on one medium, virtual reality (VR), and advocates a transparent or "invisible style" of interaction. We argue that transparency keeps users in the "flow" of their activities and consequently enhances experience in users. Breakdown in activities breaks the experience and subsequently provides opportunities to identify and analyze potential causes of usability problems. Adopting activity theory, we devise a model of interaction with VR--through consciousness and activity--and introduce the concept of breakdown in illusion. From this, a model of effective interaction with VR is devised and the occurrence of breakdown in interaction and illusion is identified along a continuum of engagement. Evaluation guidelines for the design of experience are proposed and applied to usability problems detected in an empirical study of a head-mounted display (HMD) VR system. This study shows that the guidelines are effective in the evaluation of VR. Finally, we look at the potential experiences that may be induced in users and propose a way to evaluate user experience in virtual environments (VEs) and other new and emerging media.

  12. Models for the circumstellar medium of long gamma-ray burst progenitor candidates

    NARCIS (Netherlands)

    Marle, A.J. van

    2006-01-01

    Long gamma-ray bursts are highly energetic events that are thought to occur when certain massive stars, that end their lives as Wolf-Rayet stars, collapse at the end of their evolution. We present models of the circumstellar medium around those massive stars that are thought to be possible

  13. Online public health preparedness training programs: an evaluation of user experience with the technological environment.

    Science.gov (United States)

    Nambisan, Priya

    2010-01-01

    Several public health education programs and government agencies across the country have started offering virtual or online training programs in emergency preparedness for people who are likely to be involved in managing or responding to different types of emergency situations such as natural disasters, epidemics, bioterrorism, etc. While such online training programs are more convenient and cost-effective than traditional classroom-based programs, their success depends to a great extent on the underlying technological environment. Specifically, in an online technological environment, different types of user experiences come in to play-users' utilitarian or pragmatic experience, their fun or hedonic experience, their social experience, and most importantly, their usability experience-and these different user experiences critically shape the program outcomes, including course completion rates. This study adopts a multi-disciplinary approach and draws on theories in human computer interaction, distance learning theories, usability research, and online consumer behavior to evaluate users' experience with the technological environment of an online emergency preparedness training program and discusses its implications for the design of effective online training programs. . Data was collected using a questionnaire from 377 subjects who had registered for and participated in online public health preparedness training courses offered by a large public university in the Northeast. Analysis of the data indicates that as predicted, participants had higher levels of pragmatic and usability experiences compared to their hedonic and sociability experiences. Results also indicate that people who experienced higher levels of pragmatic, hedonic, sociability and usability experiences were more likely to complete the course(s) they registered for compared to those who reported lower levels. The study findings hold important implications for the design of effective online emergency

  14. Data Quality Monitoring : Automatic MOnitoRing Environment (AMORE ) Web Administration Tool in ALICE Experiment

    CERN Document Server

    Nagi, Imre

    2013-01-01

    ALICE (A Large Ion Collider Experiment) is the heavy-ion detector designed to study the physics of strongly interacting matter and the quark-gluon plasma at the CERN Large Hadron Collider (LHC). The quality of the acquired data evolves over time depending on the status of the detectors, its components and the operating environment. To get an excellent performance of detector, all detector configurations have to be set perfectly so that the data-taking can be done in an optimal way. This report describes a new implementation of the administration tools of the ALICE’s DQM framework called AMORE (Automatic MonitoRing Environment) with web technologies.

  15. Simulation experience enhances physical therapist student confidence in managing a patient in the critical care environment.

    Science.gov (United States)

    Ohtake, Patricia J; Lazarus, Marcilene; Schillo, Rebecca; Rosen, Michael

    2013-02-01

    Rehabilitation of patients in critical care environments improves functional outcomes. This finding has led to increased implementation of intensive care unit (ICU) rehabilitation programs, including early mobility, and an associated increased demand for physical therapists practicing in ICUs. Unfortunately, many physical therapists report being inadequately prepared to work in this high-risk environment. Simulation provides focused, deliberate practice in safe, controlled learning environments and may be a method to initiate academic preparation of physical therapists for ICU practice. The purpose of this study was to examine the effect of participation in simulation-based management of a patient with critical illness in an ICU setting on levels of confidence and satisfaction in physical therapist students. A one-group, pretest-posttest, quasi-experimental design was used. Physical therapist students (N=43) participated in a critical care simulation experience requiring technical (assessing bed mobility and pulmonary status), behavioral (patient and interprofessional communication), and cognitive (recognizing a patient status change and initiating appropriate responses) skill performance. Student confidence and satisfaction were surveyed before and after the simulation experience. Students' confidence in their technical, behavioral, and cognitive skill performance increased from "somewhat confident" to "confident" following the critical care simulation experience. Student satisfaction was highly positive, with strong agreement the simulation experience was valuable, reinforced course content, and was a useful educational tool. Limitations of the study were the small sample from one university and a control group was not included. Incorporating a simulated, interprofessional critical care experience into a required clinical course improved physical therapist student confidence in technical, behavioral, and cognitive performance measures and was associated with high

  16. Exploring experiences of the food environment among immigrants living in the Region of Waterloo, Ontario.

    Science.gov (United States)

    Rodriguez, Paulina I; Dean, Jennifer; Kirkpatrick, Sharon; Berbary, Lisbeth; Scott, Steffanie

    2016-06-09

    This exploratory study aimed to shed light on the role of the food environment in shaping food access among immigrants living in the Region of Waterloo, Ontario. In this qualitative case study, in-depth interviews aided by photovoice were conducted with nine immigrants, and key informant (KI) interviews were conducted with nine community stakeholders (e.g., settlement workers, planners) who held expert knowledge of the local context with respect to both the food system and experiences of immigrants in interacting with this system. In this paper, we focus specifically on insights related to the food environment, applying the Analysis Grid for Environments Linked to Obesity Framework to assess economic, physical, socio-cultural and political aspects. Economic features of the food environment, including food prices and differential costs of different types of food, emerged as factors related to food access. However, interactions with the food environment were shaped by broader economic factors, such as limited employment opportunities and low income. Most immigrants felt that they had good geographic access to food, though KIs expressed concerns about the types of outlet and food that were most accessible. Immigrants discussed social networks and cultural food practices, whereas KIs discussed political issues related to supporting food security in the Region. This exploratory case study is consistent with prior research in highlighting the economic constraints within which food access exists but suggests that there may be a need to further dissect food environments.

  17. Interstellar Chemistry Special Feature: The chemistry in circumstellar envelopes of evolved stars: Following the origin of the elements to the origin of life

    Science.gov (United States)

    Ziurys, Lucy M.

    2006-08-01

    Mass loss from evolved stars results in the formation of unusual chemical laboratories: circumstellar envelopes. Such envelopes are found around carbon- and oxygen-rich asymptotic giant branch stars and red supergiants. As the gaseous material of the envelope flows from the star, the resulting temperature and density gradients create a complex chemical environment involving hot, thermodynamically controlled synthesis, molecule "freeze-out," shock-initiated reactions, and photochemistry governed by radical mechanisms. In the circumstellar envelope of the carbon-rich star IRC+10216, >50 different chemical compounds have been identified, including such exotic species as C8H, C3S, SiC3, and AlNC. The chemistry here is dominated by molecules containing long carbon chains, silicon, and metals such as magnesium, sodium, and aluminum, which makes it quite distinct from that found in molecular clouds. The molecular composition of the oxygen-rich counterparts is not nearly as well explored, although recent studies of VY Canis Majoris have resulted in the identification of HCO+, SO2, and even NaCl in this object, suggesting chemical complexity here as well. As these envelopes evolve into planetary nebulae with a hot, exposed central star, synthesis of molecular ions becomes important, as indicated by studies of NGC 7027. Numerous species such as HCO+, HCN, and CCH are found in old planetary nebulae such as the Helix. This "survivor" molecular material may be linked to the variety of compounds found recently in diffuse clouds. Organic molecules in dense interstellar clouds may ultimately be traced back to carbon-rich fragments originally formed in circumstellar shells.

  18. Circumstellar Disks and Outflows in Turbulent Molecular Cloud Cores: Possible Formation Mechanism for Misaligned Systems

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Tomoaki [Faculty of Sustainability Studies, Hosei University, Fujimi, Chiyoda-ku, Tokyo 102-8160 (Japan); Machida, Masahiro N. [Department of Earth and Planetary Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Inutsuka, Shu-ichiro, E-mail: matsu@hosei.ac.jp [Department of Physics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan)

    2017-04-10

    We investigate the formation of circumstellar disks and outflows subsequent to the collapse of molecular cloud cores with the magnetic field and turbulence. Numerical simulations are performed by using an adaptive mesh refinement to follow the evolution up to ∼1000 years after the formation of a protostar. In the simulations, circumstellar disks are formed around the protostars; those in magnetized models are considerably smaller than those in nonmagnetized models, but their size increases with time. The models with stronger magnetic fields tend to produce smaller disks. During evolution in the magnetized models, the mass ratios of a disk to a protostar is approximately constant at ∼1%–10%. The circumstellar disks are aligned according to their angular momentum, and the outflows accelerate along the magnetic field on the 10–100 au scale; this produces a disk that is misaligned with the outflow. The outflows are classified into two types: a magnetocentrifugal wind and a spiral flow. In the latter, because of the geometry, the axis of rotation is misaligned with the magnetic field. The magnetic field has an internal structure in the cloud cores, which also causes misalignment between the outflows and the magnetic field on the scale of the cloud core. The distribution of the angular momentum vectors in a core also has a non-monotonic internal structure. This should create a time-dependent accretion of angular momenta onto the circumstellar disk. Therefore, the circumstellar disks are expected to change their orientation as well as their sizes in the long-term evolutions.

  19. Experiences to be a family caregiver of dependent elderly in the home environment

    Directory of Open Access Journals (Sweden)

    Alcimar Marcelo do Couto

    2016-02-01

    Full Text Available Objective: to understand the experience of caring for dependent elderly in the home environment, from the perspective of family caregivers that present burden and emotional distress. Methods: this is a qualitative research with a contribution in the Theory Grounded in Data. There were home visits for observation and semi-structured interviews with nine relatives of dependent elderly in self-care. Results: with the coding and analysis of empirical data, one can understand the daily cares in the care relationship with their elderly dependent relatives. The consolidated experiences underlie on positive experiences, such as solidarity by the established interaction and the maintenance of self-esteem, and negative as changes in daily routine and health, with stress identification related to the caregiver role. Conclusion: in the understanding of the family, their experiences as a caregiver in the home context varied between positive and negative aspects, which respectively minimize and maximize the feeling of burden and emotional distress.

  20. Virtual Learning Environments and Learning Forms -experiments in ICT-based learning

    DEFF Research Database (Denmark)

    Helbo, Jan; Knudsen, Morten

    2004-01-01

    This paper report the main results of a three year experiment in ICT-based distance learning. The results are based on a full scale experiment in the education, Master of Industrial Information Technology (MII) and is one of many projects deeply rooted in the project Virtual Learning Environments...... and Learning forms (ViLL). The experiment was to transfer a well functioning on-campus engineering program based on project organized collaborative learning to a technology supported distance education program. After three years the experiments indicate that adjustments are required in this transformation....... The main problem is that we do not find the same self regulatoring learning effect in the group work among the off-campus students as is the case for on-campus students. Based on feedback from evaluation questionnaires and discussions with the students didactic adjustments have been made. The revised...

  1. Formative experience mediated by virtual learning environment: science and mathematics teachers’ education in the amazon region

    Directory of Open Access Journals (Sweden)

    France Fraiha Martins

    2012-06-01

    Full Text Available This article reports results of a qualitative research, in the narrative modality. We investigated the formative experiences of teachers of Mathematics and Science through distance learning in the Amazon region, experienced in a course through the Virtual Learning Environment (VLE. We investigated under what conditions this education experience was a catalyst for teachers’ reflections on the Amazonian context of teaching science and mathematics. By using Discursive Textual Analysis some categories e merged: graduating in the Amazon region: obstacles and confrontations; AVA and Technologies: meaning (s of the education experience and the impact of the experience in the perceptions of teachers’ practices and training. The analysis of the results reveals the obstacles to the training in this context. The dynamics experienced by the use of VLE technologies and of the teachers reverberated methodological insights regarding the use of technology in teaching practices, indicating also the VLE as an alternative of (self education on the Amazon reality

  2. Learning your way in a city: experience and gender differences in configurational knowledge of one's environment.

    Science.gov (United States)

    De Goede, Maartje; Postma, Albert

    2015-01-01

    Males tend to outperform females in their knowledge of relative and absolute distances in spatial layouts and environments. It is unclear yet in how far these differences are innate or develop through life. The aim of the present study was to investigate whether gender differences in configurational knowledge for a natural environment might be modulated by experience. In order to examine this possibility, distance as well as directional knowledge of the city of Utrecht in the Netherlands was assessed in male and female inhabitants who had different levels of familiarity with this city. Experience affected the ability to solve difficult distance knowledge problems, but only for females. While the quality of the spatial representation of metric distances improved with more experience, this effect was not different for males and females. In contrast directional configurational measures did show a main gender effect but no experience modulation. In general, it seems that we obtain different configurational aspects according to different experiential time schemes. Moreover, the results suggest that experience may be a modulating factor in the occurrence of gender differences in configurational knowledge, though this seems dependent on the type of measurement. It is discussed in how far proficiency in mental rotation ability and spatial working memory accounts for these differences.

  3. CREATING SUPPORTIVE LEARNING ENVIRONMENTS: EXPERIENCES OF LESBIAN AND GAY-PARENTED FAMILIES IN SOUTH AFRICAN SCHOOLS

    Directory of Open Access Journals (Sweden)

    Diana Breshears

    2016-06-01

    Full Text Available Through in-depth interviews with 21 parents and 12 children in lesbian/gayparented families, we explored the experiences of this unique family form in South African schools. Specifically, families reflected on their positive and negative experiences in the children’s education and used these reflections to offer advice to teachers and administrators wishing better to support lesbian/ gay-parented families. The results of our study offer an understanding of the challenges and needs of this diverse family in the school system, as well as a starting point for administrators and teachers wanting to create inclusive environments for all family types.

  4. Collaborative Virtual 3D Environment for Internet-Accessible Physics Experiments

    Directory of Open Access Journals (Sweden)

    Bettina Scheucher

    2009-08-01

    Full Text Available Abstract—Immersive 3D worlds have increasingly raised the interest of researchers and practitioners for various learning and training settings over the last decade. These virtual worlds can provide multiple communication channels between users and improve presence and awareness in the learning process. Consequently virtual 3D environments facilitate collaborative learning and training scenarios. In this paper we focus on the integration of internet-accessible physics experiments (iLabs combined with the TEALsim 3D simulation toolkit in Project Wonderland, Sun's toolkit for creating collaborative 3D virtual worlds. Within such a collaborative environment these tools provide the opportunity for teachers and students to work together as avatars as they control actual equipment, visualize physical phenomenon generated by the experiment, and discuss the results. In particular we will outline the steps of integration, future goals, as well as the value of a collaboration space in Wonderland's virtual world.

  5. Can Professional Environments in Schools Promote Teacher Development? Explaining Heterogeneity in Returns to Teaching Experience

    Science.gov (United States)

    Kraft, Matthew A.; Papay, John P.

    2014-01-01

    Although wide variation in teacher effectiveness is well established, much less is known about differences in teacher improvement over time. We document that average returns to teaching experience mask large variation across individual teachers and across groups of teachers working in different schools. We examine the role of school context in explaining these differences using a measure of the professional environment constructed from teachers responses to state-wide surveys. Our analyses show that teachers working in more supportive professional environments improve their effectiveness more over time than teachers working in less supportive contexts. On average, teachers working in schools at the 75th percentile of professional environment ratings improved 38% more than teachers in schools at the 25th percentile after 10 years. PMID:25866426

  6. Conflict management style, supportive work environments and the experience of work stress in emergency nurses.

    Science.gov (United States)

    Johansen, Mary L; Cadmus, Edna

    2016-03-01

    To examine the conflict management style that emergency department (ED) nurses use to resolve conflict and to determine whether their style of managing conflict and a supportive work environment affects their experience of work stress. Conflict is a common stressor that is encountered as nurses strive to achieve patient satisfaction goals while delivering quality care. How a nurse perceives support may impact work stress levels and how they deal with conflict. A correlational design examined the relationship between supportive work environment, and conflict management style and work stress in a sample of 222 ED nurses using the expanded nurse work stress scale; the survey of perceived organisational support; and the Rahim organisational conflict inventory-II. Twenty seven percent of nurses reported elevated levels of work stress. A supportive work environment and avoidant conflict management style were significant predictors of work stress. Findings suggest that ED nurses' perception of a supportive work environment and their approach to resolving conflict may be related to their experience of work stress. Providing opportunities for ED nurses in skills training in constructive conflict resolution may help to reduce work stress and to improve the quality of patient care. © 2015 John Wiley & Sons Ltd.

  7. Severe fuel damage in steam and helium environments observed in in-reactor experiments

    International Nuclear Information System (INIS)

    Saito, S.; Shiozawa, S.

    1984-01-01

    The bahavior of severe fuel damages has been studied in gaseous environments simulating core uncovery accidents in the in-reactor experiments utilizing the NSRR. Two types of cladding relocation modes, azimuthal flow and melt-down, were revealed through the parametric experiments. The azimuthal flow was evident in an oxidizing environment in case of no oxide film break. The melt-down can be categorized into flow-down and move-down, according to the velocity of the melt-down. Cinematographies showed that the flow-down was very fast as water flows down while the move-down appeared to be much slower. The flow-down was possible in an unoxidizing environment, whereas the move-down of molten cladding occured through a crack induced in an oxide film in an oxidizing environment. The criterion of the relocation modes was developed as a function of peak cladding temperature and oxidation condition. It was also found that neither immediate quench nor fuel fracture occurred upon flooding when cladding temperature was about 1800 0 C at water injection. The external mechanical force is needed for fuel fracture. (orig.)

  8. Designing new collaborative learning spaces in clinical environments: experiences from a children's hospital in Australia.

    Science.gov (United States)

    Bines, Julie E; Jamieson, Peter

    2013-09-01

    Hospitals are complex places that provide a rich learning environment for students, staff, patients and their families, professional groups and the community. The "new" Royal Children's Hospital opened in late 2011. Its mission is focused on improving health and well-being of children and adolescents through leadership in healthcare, research and education. Addressing the need to create "responsive learning environments" aligned with the shift to student-centred pedagogy, two distinct learning environments were developed within the new Royal Children's Hospital; (i) a dedicated education precinct providing a suite of physical environments to promote a more active, collaborative and social learning experience for education and training programs conducted on the Royal Children's Hospital campus and (ii) a suite of learning spaces embedded within clinical areas so that learning becomes an integral part of the daily activities of this busy Hospital environment. The aim of this article is to present the overarching educational principles that lead the design of these learning spaces and describe the opportunities and obstacles encountered in the development of collaborative learning spaces within a large hospital development.

  9. Teachers' and postgraduate nursing students' experience of the educational environment in Iran: A qualitative Research.

    Science.gov (United States)

    Hajihosseini, Fatemeh; Tafreshi, Mansoureh Zagheri; Hosseini, Meimanat; Baghestani, Ahmad Reza

    2017-08-01

    The learning environment has a significant role in determining nursing students' academic achievements and course satisfaction. Creating a proper educational environment is therefore necessary for improving the quality of teaching and learning, and for delivering competent graduates to society. The present study was conducted to explore teachers' and postgraduate nursing students' experience of the educational environment in Iran. This qualitative study uses an inductive approach and conventional content analysis. Data were collected through semi-structured face-to-face interviews with seven PhD students, seven faculty members (directors) and two focus groups comprising of fourteen master's students in total, selected from three major universities in Tehran, Iran. Seven subcategories were extracted from the data, including the organizational context, interactive climate, teachers' competency, student appreciation, research centeredness, educational guidance and professionalism. The educational environment of postgraduate nursing programs in Iran encompasses different dimensions that can serve as both key points for educational environment evaluators and as guidelines for officials at different levels, to modify the weaknesses and improve the strengths of the system.

  10. Teachers’ and postgraduate nursing students’ experience of the educational environment in Iran: A qualitative Research

    Science.gov (United States)

    Hajihosseini, Fatemeh; Tafreshi, Mansoureh Zagheri; Hosseini, Meimanat; Baghestani, Ahmad Reza

    2017-01-01

    Background The learning environment has a significant role in determining nursing students’ academic achievements and course satisfaction. Creating a proper educational environment is therefore necessary for improving the quality of teaching and learning, and for delivering competent graduates to society. Objective The present study was conducted to explore teachers’ and postgraduate nursing students’ experience of the educational environment in Iran. Methods This qualitative study uses an inductive approach and conventional content analysis. Data were collected through semi-structured face-to-face interviews with seven PhD students, seven faculty members (directors) and two focus groups comprising of fourteen master’s students in total, selected from three major universities in Tehran, Iran. Results Seven subcategories were extracted from the data, including the organizational context, interactive climate, teachers’ competency, student appreciation, research centeredness, educational guidance and professionalism. Conclusion The educational environment of postgraduate nursing programs in Iran encompasses different dimensions that can serve as both key points for educational environment evaluators and as guidelines for officials at different levels, to modify the weaknesses and improve the strengths of the system. PMID:28979741

  11. Clinical learning environment and supervision: experiences of Norwegian nursing students - a questionnaire survey.

    Science.gov (United States)

    Skaalvik, Mari Wolff; Normann, Hans Ketil; Henriksen, Nils

    2011-08-01

    To measure nursing students' experiences and satisfaction with their clinical learning environments. The primary interest was to compare the results between students with respect to clinical practice in nursing homes and hospital wards. Clinical learning environments are important for the learning processes of nursing students and for preferences for future workplaces. Working with older people is the least preferred area of practice among nursing students in Norway. A cross-sectional design. A validated questionnaire was distributed to all nursing students from five non-randomly selected university colleges in Norway. A total of 511 nursing students completed a Norwegian version of the questionnaire, Clinical Learning Environment, Supervision and Nurse Teacher (CLES+T) evaluation scale in 2009. Data including descriptive statistics were analysed using the Statistical Program for the Social Sciences. Factor structure was analysed by principal component analysis. Differences across sub-groups were tested with chi-square tests and Mann-Whitney U test for categorical variables and t-tests for continuous variables. Ordinal logistic regression analysis of perceptions of the ward as a good learning environment was performed with supervisory relationships and institutional contexts as independent variables, controlling for age, sex and study year. The participating nursing students with clinical placements in nursing homes assessed their clinical learning environment significantly more negatively than those with hospital placements on nearby all sub-dimensions. The evidence found in this study indicates that measures should be taken to strengthen nursing homes as learning environments for nursing students. To recruit more graduated nurses to work in nursing homes, actions to improve the learning environment are needed. © 2011 Blackwell Publishing Ltd.

  12. Coupled heat transfer model and experiment study of semitransparent barrier materials in aerothermal environment

    Science.gov (United States)

    Wang, Da-Lin; Qi, Hong

    Semi-transparent materials (such as IR optical windows) are widely used for heat protection or transfer, temperature and image measurement, and safety in energy , space, military, and information technology applications. They are used, for instance, ceramic coatings for thermal barriers of spacecrafts or gas turbine blades, and thermal image observation under extreme or some dangerous environments. In this paper, the coupled conduction and radiation heat transfer model is established to describe temperature distribution of semitransparent thermal barrier medium within the aerothermal environment. In order to investigate this numerical model, one semi-transparent sample with black coating was considered, and photothermal properties were measured. At last, Finite Volume Method (FVM) was used to solve the coupled model, and the temperature responses from the sample surfaces were obtained. In addition, experiment study was also taken into account. In the present experiment, aerodynamic heat flux was simulated by one electrical heater, and two experiment cases were designed in terms of the duration of aerodynamic heating. One case is that the heater irradiates one surface of the sample continually until the other surface temperature up to constant, and the other case is that the heater works only 130 s. The surface temperature responses of these two cases were recorded. Finally, FVM model of the coupling conduction-radiation heat transfer was validated based on the experiment study with relative error less than 5%.

  13. Mentor experiences of international healthcare students' learning in a clinical environment: A systematic review.

    Science.gov (United States)

    Mikkonen, Kristina; Elo, Satu; Tuomikoski, Anna-Maria; Kääriäinen, Maria

    2016-05-01

    Globalisation has brought new possibilities for international growth in education and professional mobility among healthcare professionals. There has been a noticeable increase of international degree programmes in non-English speaking countries in Europe, creating clinical learning challenges for healthcare students. The aim of this systematic review was to describe mentors' experiences of international healthcare students' learning in a clinical environment. The objective of the review was to identify what influences the success or failure of mentoring international healthcare students when learning in the clinical environment, with the ultimate aim being to promote optimal mentoring practice. A systematic review was conducted according to the guidelines of the Centre for Reviews and Dissemination. Seven electronic databases were used to search for the published results of previous research: CINAHL, Medline Ovid, Scopus, the Web of Science, Academic Search Premiere, Eric, and the Cochrane Library. Search inclusion criteria were planned in the PICOS review format by including peer-reviewed articles published in any language between 2000 and 2014. Five peer-reviewed articles remained after the screening process. The results of the original studies were analysed using a thematic synthesis. The results indicate that a positive intercultural mentor enhanced reciprocal learning by improving the experience of international healthcare students and reducing stress in the clinical environment. Integrating international healthcare students into work with domestic students was seen to be important for reciprocal learning and the avoidance of discrimination. Many healthcare students were found to share similar experiences of mentoring and learning irrespective of their cultural background. However, the role of a positive intercultural mentor was found to make a significant difference for international students: such mentors advocated and mediated cultural differences and

  14. NEDE: an open-source scripting suite for developing experiments in 3D virtual environments.

    Science.gov (United States)

    Jangraw, David C; Johri, Ansh; Gribetz, Meron; Sajda, Paul

    2014-09-30

    As neuroscientists endeavor to understand the brain's response to ecologically valid scenarios, many are leaving behind hyper-controlled paradigms in favor of more realistic ones. This movement has made the use of 3D rendering software an increasingly compelling option. However, mastering such software and scripting rigorous experiments requires a daunting amount of time and effort. To reduce these startup costs and make virtual environment studies more accessible to researchers, we demonstrate a naturalistic experimental design environment (NEDE) that allows experimenters to present realistic virtual stimuli while still providing tight control over the subject's experience. NEDE is a suite of open-source scripts built on the widely used Unity3D game development software, giving experimenters access to powerful rendering tools while interfacing with eye tracking and EEG, randomizing stimuli, and providing custom task prompts. Researchers using NEDE can present a dynamic 3D virtual environment in which randomized stimulus objects can be placed, allowing subjects to explore in search of these objects. NEDE interfaces with a research-grade eye tracker in real-time to maintain precise timing records and sync with EEG or other recording modalities. Python offers an alternative for experienced programmers who feel comfortable mastering and integrating the various toolboxes available. NEDE combines many of these capabilities with an easy-to-use interface and, through Unity's extensive user base, a much more substantial body of assets and tutorials. Our flexible, open-source experimental design system lowers the barrier to entry for neuroscientists interested in developing experiments in realistic virtual environments. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Impact of protected mealtimes on ward mealtime environment, patient experience and nutrient intake in hospitalised patients.

    Science.gov (United States)

    Hickson, M; Connolly, A; Whelan, K

    2011-08-01

    Malnutrition is a common problem in hospitalised inpatients, resulting in a range of negative clinical, patient-centred and economic sequelae. Protected mealtimes (PM) aim to enhance the quality of the mealtime experience and maximise nutrient intake in hospitalised patients. The present study aimed to measure mealtime environment, patient experience and nutrient intake before and after the implementation of PM.   PM were implemented in a large teaching hospital through a range of different approaches. Direct observations were used to assess ward-level mealtime environment (e.g. dining room use, removal of distractions) (40 versus 34 wards) and individual patient experience (e.g. assistance with eating, visitors present) (253 versus 237 patients), and nutrient intake was assessed with a weighed food intake at lunch (39 versus 60 patients) at baseline and after the implementation of PM, respectively. Mealtime experience showed improvements in three objectives: more patients were monitored using food/fluid charts (32% versus 43%, P = 0.02), more were offered the opportunity to wash hands (30% versus 40%, P = 0.03) and more were served meals at uncluttered tables (54% versus 64%, P = 0.04). There was no difference in the number of patients experiencing mealtime interruptions (32% versus 25%, P = 0.14). There was no difference in energy intake (1088 versus 837 kJ, P = 0.25) and a decrease in protein intake (14.0 versus 7.5 g, P = 0.04) after PM. Only minor improvements in mealtime experience were made after the implementation of PM and so it is not unexpected that macronutrient intake did not improve. The implementation of PM needs to be evaluated to ensure improvements in mealtime experience are made such that measurable improvements in nutritional and clinical outcomes ensue. © 2011 The Authors. Journal of Human Nutrition and Dietetics © 2011 The British Dietetic Association Ltd.

  16. Using the computer-driven VR environment to promote experiences of natural world immersion

    Science.gov (United States)

    Frank, Lisa A.

    2013-03-01

    In December, 2011, over 800 people experienced the exhibit, :"der"//pattern for a virtual environment, created for the fully immersive CAVETM at the University of Wisconsin-Madison. This exhibition took my nature-based photographic work and reinterpreted it for virtual reality (VR).Varied responses such as: "It's like a moment of joy," or "I had to see it twice," or "I'm still thinking about it weeks later" were common. Although an implied goal of my 2D artwork is to create a connection that makes viewers more aware of what it means to be a part of the natural world, these six VR environments opened up an unexpected area of inquiry that my 2D work has not. Even as the experience was mediated by machines, there was a softening at the interface between technology and human sensibility. Somehow, for some people, through the unlikely auspices of a computer-driven environment, the project spoke to a human essence that they connected with in a way that went beyond all expectations and felt completely out of my hands. Other interesting behaviors were noted: in some scenarios some spoke of intense anxiety, acrophobia, claustrophobia-even fear of death when the scene took them underground. These environments were believable enough to cause extreme responses and disorientation for some people; were fun, pleasant and wonder-filled for most; and were liberating, poetic and meditative for many others. The exhibition seemed to promote imaginative skills, creativity, emotional insight, and environmental sensitivity. It also revealed the CAVETM to be a powerful tool that can encourage uniquely productive experiences. Quite by accident, I watched as these nature-based environments revealed and articulated an essential relationship between the human spirit and the physical world. The CAVETM is certainly not a natural space, but there is clear potential to explore virtual environments as a path to better and deeper connections between people and nature. We've long associated contact

  17. Examples of Small-scale Urban Area. Experiment Energy Leap Built Environment; Voorbeeldenboek Kleinschalige Binnenstedelijke Gebieden. Experiment Energiesprong Gebouwde Omgeving

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-03-15

    The Dutch government considers the transition process to be necessary and stimulates investments in energy innovations in the built environment. This innovation effort is the programme 'Energy Leap' (Energiesprong), which is being carried out by the Steering Group Experimental Housing (SEV) on behalf of the Dutch Ministry of the Interior and Kingdom Relations (BZK). The programme is derived from the Innovation Agenda for Energy in the Built Environment. The examples in this book are intended to inspire (potential) participants in the Experiment Energy Leap for Small-scale Urban Areas. The examples focus explicitly on the reduction of CO2 emissions in urban areas, and thus, in addition to CO2 reduction on a building level, the aspects of energy supply, (local) energy production and the energy infrastructure [Dutch] Het SEV-programma Energiesprong (SEV is Stuurgroep Experimenten Volkshuisvesting) beoogt een substantiele bijdrage te leveren aan de condities waaronder de energietransitie effectief tot stand kan komen. In dit basisplan wordt uiteengezet hoe de markt daartoe moet kunnen komen en welke activiteiten daarvoor worden ondersteund, opgezet en/of uitgevoerd vanuit Energiesprong. Het SEV-programma Energiesprong wordt in opdracht van het Ministerie van Binnenlandse Zaken en Koninkrijksrelaties (BZK) uitgevoerd. Het programma is afgeleid van de Innovatie Agenda energie Gebouwde Omgeving. Dit voorbeeldenboek dient ter inspiratie van (potentiele) deelnemers aan het Experiment Energiesprong kleinschalige Binnenstedelijke Gebieden. De voorbeelden richten zich expliciet op de CO2-reductie van binnenstedelijke gebieden en daarmee, naast de CO2-reductie op woning- en gebouwniveau, op de aspecten energievoorziening, (locale) energieopwekking en energie-infrastructuur.

  18. A new practice environment measure based on the reality and experiences of nurses working lives.

    Science.gov (United States)

    Webster, Joan; Flint, Anndrea; Courtney, Mary

    2009-01-01

    To explore the underlying organizational issues affecting a nurses' decision to leave and to develop a contemporary practice environment measure based on the experiences of nurses working lives. Turnover had reached an unacceptable level in our organization but underlying reasons for leaving were unknown. In-depth interviews were conducted with 13 nurses who had resigned. Transcripts were analysed using the constant comparative method. Information from the interviews informed the development a new practice environment tool, which has undergone initial testing using the Content Validity Index and Chronbach's alpha. Two domains ('work life' and 'personal life/professional development') and five themes ('feeling safe', 'feeling valued', 'getting things done', 'professional development' and 'being flexible') emerged from the interviews. A content validity score for the new instrument was 0.79 and Chronbach's alpha 0.93. The new practice environment tool has shown useful initial reliability and validity but requires wider testing in other settings. The reality and experiences of nurses working lives can be identified through exit interviews conducted by an independent person. Information from such interviews is useful in identifying an organization's strength and weaknesses and to develop initiatives to support retention.

  19. Paramedics' experiences of financial medicine practices in the pre-hospital environment. A pilot study

    Directory of Open Access Journals (Sweden)

    Craig Vincent-Lambert

    2016-10-01

    Objectives: This qualitative pilot study explored and described the experiences of South African Paramedics with regard to the practicing of financial medicine in the local pre-hospital emergency care environment. Method: A sample of South African Paramedics were interviewed either face-to-face or telephonically. The interviews were audio recorded and transcripts produced. Content analysis was conducted to explore, document and describe the participants' experiences with regard to financial medicine practices in the local pre-hospital environment. Results: It emerged that all of the participants had experienced a number of financial medicine practices and associated unethical conduct. Examples included Over-servicing, Selective Patient Treatment, Fraudulent Billing Practices, Eliciting of kickbacks, incentives or benefits and Deliberate Time Wasting. Conclusion: The results of this study are concerning as the actions of service providers described by the participants constitute gross violations of the ethical and professional guidelines for health care professionals. The authors recommend additional studies be conducted to further explore these findings and to establish the reasons for, and ways of, limiting financial medicine practices in the South African emergency care environment.

  20. Using a Virtual Environment to Deliver Evidence-Based Interventions: The Facilitator's Experience

    Science.gov (United States)

    Villarruel, Antonia; Tschannen, Dana; Valladares, Angel; Yaksich, Joseph; Yeagley, Emily; Hawes, Armani

    2015-01-01

    Background Evidence-based interventions (EBIs) have the potential to maximize positive impact on communities. However, despite the quantity and quality of EBIs for prevention, the need for formalized training and associated training-related expenses, such as travel costs, program materials, and input of personnel hours, pose implementation challenges for many community-based organizations. In this study, the community of inquiry (CoI) framework was used to develop the virtual learning environment to support the adaptation of the ¡Cuídate! (Take Care of Yourself!) Training of Facilitators curriculum (an EBI) to train facilitators from community-based organizations. Objective The purpose of this study was to examine the feasibility of adapting a traditional face-to-face facilitator training program for ¡Cuídate!, a sexual risk reduction EBI for Latino youth, for use in a multi-user virtual environment (MUVE). Additionally, two aims of the study were explored: the acceptability of the facilitator training and the level of the facilitators’ knowledge and self-efficacy to implement the training. Methods A total of 35 facilitators were trained in the virtual environment. We evaluated the facilitators' experience in the virtual training environment and determined if the learning environment was acceptable and supported the acquisition of learning outcomes. To this end, the facilitators were surveyed using a modified community of inquiry survey, with questions specific to the Second Life environment and an open-ended questionnaire. In addition, a comparison to face-to-face training was conducted using survey methods. Results Results of the community of inquiry survey demonstrated a subscale mean of 23.11 (SD 4.12) out of a possible 30 on social presence, a subscale mean of 8.74 (SD 1.01) out of a possible 10 on teaching presence, and a subscale mean of 16.69 (SD 1.97) out of a possible 20 on cognitive presence. The comparison to face-to-face training showed no

  1. Improving delivery of a health-promoting-environments program: experiences from Queensland Health.

    Science.gov (United States)

    Dwyer, S

    1997-01-01

    The purpose of this paper is to outline the key components of a statewide multisite health-promoting-environments program. Contemporary health-promotion programs in settings such as schools, workplaces and hospitals use organisational development theory to address the health issues of the setting, including the physical environment, the organisational environment, and the specific health needs of the employees and consumers of the service. Program principles include management of each project by the participant organisation or site (for example, a school or workplace), using resources available within the organisation and the local community, voluntary participation, social justice and participant-based priority setting, and evaluation and monitoring. Adoption of these principles implies a shift in the role of the health worker from implementer to facilitator. Based on the experience of Queensland Health, it is proposed that the essential building blocks of the health-promoting-environments program are an intersectoral policy base, a model for action, training and resources, local facilitators, support from local organisations, a supportive network of sites, marketing of the program, and a state-based evaluation and monitoring system. The program in Queensland was able to develop a significant number of these components over the 1990-1996 period. In regard to evaluation, process measures can be built around the program components; however, further research is required for development of impact indicators and benchmarks on quality.

  2. Collaborative learning environments and collective creation in 3 weeks bside project experience

    Directory of Open Access Journals (Sweden)

    Carlos Javier Rodríguez Sánchez

    2016-07-01

    Full Text Available This  paper proposes  a  socio-critical review  and  reflection  related to collaborative learning environment as pedagogical agent and its relationship with artistic-practice communities of collective creativity. The main goal of this research is to introduce the case study 3 weeks bside project experience (3WBPE, from now on. Through participatory action research and the analysis of different concepts and their practical and theoretical aspects. In the framework of an education self-manage- ment development universe, the project pro- cess is based on a collaborative learning. It is focused on the constructions of a common discourse about the idea of territory that is represented in a publication and site specific exhibition. 3WBPE allowed setting up stanc- es that suggest a social interaction transfer related to construction of belong, participa- tion and transformation environment, ques- tion a teacher role or collective creation of a project, emphasizing the importance of pro- cess as a goal, beyond of culture artifact pro- ductions. It was dealt with dialog structures, where a social harmony supposed a personal and common reflection space about author’s stance, nigh socio-culture environments and the bond within the education, arts and visu- al culture focused in the horizontal and flexi- ble work capacity, that proposes a collabora- tive learning environment settings.

  3. Technical experiences of implementing a wireless tracking and facial biometric verification system for a clinical environment

    Science.gov (United States)

    Liu, Brent; Lee, Jasper; Documet, Jorge; Guo, Bing; King, Nelson; Huang, H. K.

    2006-03-01

    By implementing a tracking and verification system, clinical facilities can effectively monitor workflow and heighten information security in today's growing demand towards digital imaging informatics. This paper presents the technical design and implementation experiences encountered during the development of a Location Tracking and Verification System (LTVS) for a clinical environment. LTVS integrates facial biometrics with wireless tracking so that administrators can manage and monitor patient and staff through a web-based application. Implementation challenges fall into three main areas: 1) Development and Integration, 2) Calibration and Optimization of Wi-Fi Tracking System, and 3) Clinical Implementation. An initial prototype LTVS has been implemented within USC's Healthcare Consultation Center II Outpatient Facility, which currently has a fully digital imaging department environment with integrated HIS/RIS/PACS/VR (Voice Recognition).

  4. A qualitative report on the subjective experience of intravenous psilocybin administered in an FMRI environment.

    Science.gov (United States)

    Turton, S; Nutt, D J; Carhart-Harris, R L

    2014-01-01

    This report documents the phenomenology of the subjective experiences of 15 healthy psychedelic experienced volunteers who were involved in a functional magnetic resonance imaging (fMRI) study that was designed to image the brain effects of intravenous psilocybin. The participants underwent a semi-structured interview exploring the effects of psilocybin in the MRI scanner. These interviews were analysed by Interpretative Phenomenological Analysis. The resultant data is ordered in a detailed matrix, and presented in this paper. Nine broad categories of phenomenology were identified in the phenomenological analysis of the experience; perceptual changes including visual, auditory and somatosensory distortions, cognitive changes, changes in mood, effects of memory, spiritual or mystical type experiences, aspects relating to the scanner and research environment, comparisons with other experiences, the intensity and onset of effects, and individual interpretation of the experience. This article documents the phenomenology of psilocybin when given in a novel manner (intravenous injection) and setting (an MRI scanner). The findings of the analysis are consistent with previous published work regarding the subjective effects of psilocybin. There is much scope for further research investigating the phenomena identified in this paper.

  5. CIRCUMSTELLAR MAGNETITE FROM THE LAP 031117 CO3.0 CHONDRITE

    Energy Technology Data Exchange (ETDEWEB)

    Zega, Thomas J. [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd, Tucson, AZ 85721-0092 (United States); Haenecour, Pierre; Floss, Christine [Laboratory for Space Sciences and Physics Department, Washington University, One Brookings Drive, Campus Box 1105, St. Louis, MO 63130 (United States); Stroud, Rhonda M., E-mail: tzega@lpl.arizona.edu [Materials Science and Technology Division, Code 6366, Naval Research Laboratory, 4555 Overlook Ave, SW Washington, DC 20375 (United States)

    2015-07-20

    We report the first microstructural confirmation of circumstellar magnetite, identified in a petrographic thin section of the LaPaz Icefield 031117 CO3.0 chondrite. The O-isotopic composition of the grain indicates an origin in a low-mass (∼2.2 M{sub ⊙}), approximately solar metallicity red/asymptotic giant branch (RGB/AGB) star undergoing first dredge-up. The magnetite is a single crystal measuring 750 × 670 nm, is free of defects, and is stoichiometric Fe{sub 3}O{sub 4}. We hypothesize that the magnetite formed via oxidation of previously condensed Fe dust within the circumstellar envelope of its progenitor star. Using an empirically derived rate constant for this reaction, we calculate that such oxidation could have occurred over timescales ranging from approximately ∼9000–500,000 years. This timescale is within the lifetime of estimates for dust condensation within RGB/AGB stars.

  6. Heterodyne spatial interferometry of circumstellar dust shells at a wavelength of 11 microns

    International Nuclear Information System (INIS)

    Sutton, E.C.

    1979-01-01

    The spatial distribution of the 11 micron thermal emission from circumstellar dust envelopes has been studied using an infrared heterodyne interferometer. Circumstellar dust envelopes often exist around cool, late-type stars. These envelopes radiate strongly at 11 microns, particularly if they are composed of silicate grains, which have a strong emission feature near this wavelength. By measuring the spatial distribution of this dust emission it is possible to probe the temperatures and densities of the circumstellar material and thereby to gain an understanding of the structures of circumstellar envelopes. Among the sources which have been observed with this interferometer are α Orionis, o Ceti, VY Canis Majoris, and IRC + 10216. The 11 micron brightness distributions of these objects all have spatially extended dust-emission components which are resolved in these measurements. The dust envelopes of α Orionis and o Ceti are optically thin, having optical depths at 11 microns of 0.02 and 0.04, respectively. In addition, variations are seen in the 11 micron brightness distribution of o Ceti which correlate with the stellar variability. These variations primarily represent changes in the relative amount of spatially compact photospheric emission and spatially extended dust emission. The source VY Canis Majoris, on the other had, has a dust envelope which is optically thick at 11 microns. The dust envelope of IRC + 10216, although optically thick at visible wavelengths, does not seem to be optically thick at 11 microns since there is a spatially compact component of the 11 micron brightness distribution which presumably represents emission from the central star

  7. Disk Detective: Discovery of New Circumstellar Disk Candidates through Citizen Science

    OpenAIRE

    Kuchner, Marc J.; Silverberg, Steven M.; Bans, Alissa S.; Bhattacharjee, Shambo; Kenyon, Scott J.; Debes, John H.; Currie, Thayne; Garcia, Luciano; Jung, Dawoon; Lintott, Chris; McElwain, Michael; Padgett, Deborah L.; Rebull, Luisa M.; Wisniewski, John P.; Nesvold, Erika

    2016-01-01

    The Disk Detective citizen science project aims to find new stars with 22 μm excess emission from circumstellar dust using data from NASA's Wide-field Infrared Survey Explorer (WISE) mission. Initial cuts on the AllWISE catalog provide an input catalog of 277,686 sources. Volunteers then view images of each source online in 10 different bands to identify false positives (galaxies, interstellar matter, image artifacts, etc.). Sources that survive this online vetting are followed up with spectr...

  8. The Polluted Atmosphere of the White Dwarf NLTT 25792 and the Diversity of Circumstellar Environments

    Czech Academy of Sciences Publication Activity Database

    Vennes, Stephane; Kawka, Adela

    2013-01-01

    Roč. 779, č. 1 (2013), 70/1-70/10 ISSN 0004-637X R&D Projects: GA ČR GA13-14581S; GA ČR GAP209/12/0217 Institutional support: RVO:67985815 Keywords : stars * abundances * atmospheres Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 6.280, year: 2013

  9. THE CIRCUMSTELLAR ENVIRONMENT OF R CORONAE BOREALIS: WHITE DWARF MERGER OR FINAL-HELIUM-SHELL FLASH?

    Energy Technology Data Exchange (ETDEWEB)

    Clayton, Geoffrey C.; Andrews, J. E. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Sugerman, Ben E. K. [Department of Physics and Astronomy, Goucher College, 1021 Dulaney Valley Rd., Baltimore, MD 21204 (United States); Adam Stanford, S. [IGPP, Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Whitney, B. A. [Space Science Institute, 4750 Walnut St. Suite 205, Boulder, CO 80301 (United States); Honor, J.; Babler, B. [Department of Astronomy, 475 North Charter St., University of Wisconsin, Madison, WI 53706 (United States); Barlow, M. J. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Gordon, K. D.; Bond, Howard E.; Matsuura, M. [STScI, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Geballe, T. R. [Gemini Observatory, 670 N. A' ohoku Place, Hilo, HI 96720 (United States); De Marco, O. [Department of Physics, Macquarie University, Sydney, NSW 2109 (Australia); Lawson, W. A. [School of PEMS, University of New South Wales, ADFA, P.O. Box 7916, Canberra, ACT 2610 (Australia); Sibthorpe, B. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Olofsson, G. [Department of Astronomy, Stockholm University, AlbaNova University Center, Roslagstullsbacken 21, SE-10691 Stockholm (Sweden); Polehampton, E. [Space Science and Technology Department, Rutherford Appleton Laboratory, Didcot OX11 0QX (United Kingdom); Gomez, H. L.; Hargrave, P. C. [School of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff, Wales CF24 3YB (United Kingdom); Ivison, R. J., E-mail: gclayton@phys.lsu.edu, E-mail: jandrews@phys.lsu.edu, E-mail: ben.sugerman@goucher.edu, E-mail: stanford@physics.ucdavis.edu, E-mail: bwhitney@spacescience.org, E-mail: jhonor@astro.wisc.edu, E-mail: brian@astro.wisc.edu, E-mail: mjb@star.ucl.ac.uk [UK Astronomy Technology Centre, ROE, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); and others

    2011-12-10

    In 2007, R Coronae Borealis (R CrB) went into a historically deep and long decline. In this state, the dust acts like a natural coronagraph at visible wavelengths, allowing faint nebulosity around the star to be seen. Imaging has been obtained from 0.5 to 500 {mu}m with Gemini/GMOS, Hubble Space Telescope/WFPC2, Spitzer/MIPS, and Herschel/SPIRE. Several of the structures around R CrB are cometary globules caused by wind from the star streaming past dense blobs. The estimated dust mass of the knots is consistent with their being responsible for the R CrB declines if they form along the line of sight to the star. In addition, there is a large diffuse shell extending up to 4 pc away from the star containing cool 25 K dust that is detected all the way out to 500 {mu}m. The spectral energy distribution of R CrB can be well fitted by a 150 AU disk surrounded by a very large diffuse envelope which corresponds to the size of the observed nebulosity. The total masses of the disk and envelope are 10{sup -4} and 2 M{sub Sun }, respectively, assuming a gas-to-dust ratio of 100. The evidence pointing toward a white dwarf merger or a final-helium-shell flash origin for R CrB is contradictory. The shell and the cometary knots are consistent with a fossil planetary nebula. Along with the fact that R CrB shows significant lithium in its atmosphere, this supports the final-helium-shell flash. However, the relatively high inferred mass of R CrB and its high fluorine abundance support a white dwarf merger.

  10. THE CIRCUMSTELLAR ENVIRONMENT OF R CORONAE BOREALIS: WHITE DWARF MERGER OR FINAL-HELIUM-SHELL FLASH?

    International Nuclear Information System (INIS)

    Clayton, Geoffrey C.; Andrews, J. E.; Sugerman, Ben E. K.; Adam Stanford, S.; Whitney, B. A.; Honor, J.; Babler, B.; Barlow, M. J.; Gordon, K. D.; Bond, Howard E.; Matsuura, M.; Geballe, T. R.; De Marco, O.; Lawson, W. A.; Sibthorpe, B.; Olofsson, G.; Polehampton, E.; Gomez, H. L.; Hargrave, P. C.; Ivison, R. J.

    2011-01-01

    In 2007, R Coronae Borealis (R CrB) went into a historically deep and long decline. In this state, the dust acts like a natural coronagraph at visible wavelengths, allowing faint nebulosity around the star to be seen. Imaging has been obtained from 0.5 to 500 μm with Gemini/GMOS, Hubble Space Telescope/WFPC2, Spitzer/MIPS, and Herschel/SPIRE. Several of the structures around R CrB are cometary globules caused by wind from the star streaming past dense blobs. The estimated dust mass of the knots is consistent with their being responsible for the R CrB declines if they form along the line of sight to the star. In addition, there is a large diffuse shell extending up to 4 pc away from the star containing cool 25 K dust that is detected all the way out to 500 μm. The spectral energy distribution of R CrB can be well fitted by a 150 AU disk surrounded by a very large diffuse envelope which corresponds to the size of the observed nebulosity. The total masses of the disk and envelope are 10 –4 and 2 M ☉ , respectively, assuming a gas-to-dust ratio of 100. The evidence pointing toward a white dwarf merger or a final-helium-shell flash origin for R CrB is contradictory. The shell and the cometary knots are consistent with a fossil planetary nebula. Along with the fact that R CrB shows significant lithium in its atmosphere, this supports the final-helium-shell flash. However, the relatively high inferred mass of R CrB and its high fluorine abundance support a white dwarf merger.

  11. Evolution of silicate dust in interstellar, circumstellar and cometary environments: the role of irradiation and temperature

    International Nuclear Information System (INIS)

    Davoisne, Carine

    2006-01-01

    Due to the development of observational and analytical tools, our knowledge of the silicate dust has considerably increased these last years. Dust is formed around evolved stars and injected in the interstellar medium (ISM) in which it travels. Dust is then incorporated in the proto-planetary disks around young stars. During its life cycle, the silicate dust is subjected by numerous processes. The aim of this PhD work is firstly to study the chemical and morphological modifications of silicate dust in supernovae shock waves then to indicate its evolution when it is incorporated around young stars. We have developed low energy ion irradiations in situ in a photoelectron spectrometer (XPS). The chemical and morphological changes have been measured respectively by XPS and atomic force microscopy. We have also carried out thermal annealing under controlled atmosphere of amorphous silicates. The structural and chemical modifications have been observed by analytical transmission electron microscopy. We have shown that ion irradiation induces chemical and morphological changes in silicate. In the ISM, supernovae shock waves are thus a major process which could affect the silicate dust evolution. The microstructure obtained after thermal annealing strongly depends on oxygen fugacity. They often offer a good comparison with those observed in primitive materials present in our solar system. The recrystallization of amorphous interstellar precursors in the inner accretion disk is thus an efficient process to form crystalline silicates which are furthermore incorporated in small parent bodies (asteroids or comets). (author) [fr

  12. Radio observations reveal a smooth circumstellar environment around the extraordinary type Ib supernova 2012au

    Energy Technology Data Exchange (ETDEWEB)

    Kamble, Atish; Soderberg, Alicia M.; Margutti, Raffaella; Milisavljevic, Dan; Chakraborti, Sayan; Dittmann, Jason; Drout, Maria; Sanders, Nathan [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Chomiuk, Laura [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Medvedev, Mikhail [The Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045 (United States); Chevalier, Roger [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Chugai, Nikolai [Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya 48, 109017 Moscow (Russian Federation); Fransson, Claes [Department of Astronomy, The Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Nakar, Ehud, E-mail: atish.vyas@gmail.com [Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)

    2014-12-10

    We present extensive radio and X-ray observations of SN 2012au, an energetic, radio-luminous supernova of Type Ib that exhibits multi-wavelength properties bridging subsets of hydrogen-poor superluminous supernovae, hypernovae, and normal core-collapse supernovae. The observations closely follow models of synchrotron emission from a shock-heated circumburst medium that has a wind density profile (ρ∝r {sup –2}). We infer a sub-relativistic velocity for the shock wave v ≈ 0.2 c and a radius of r ≈ 1.4 × 10{sup 16}cm at 25 days after the estimated date of explosion. For a wind velocity of 1000 km s{sup –1}, we determine the mass-loss rate of the progenitor to be M-dot =3.6×10{sup −6} M{sub ⊙} yr{sup −1}, consistent with the estimates from X-ray observations. We estimate the total internal energy of the radio-emitting material to be E ≈ 10{sup 47} erg, which is intermediate to SN 1998bw and SN 2002ap. The evolution of the radio light curve of SN 2012au is in agreement with its interaction with a smoothly distributed circumburst medium and the absence of stellar shells ejected from previous outbursts out to r ≈ 10{sup 17} cm from the supernova site. We conclude that the bright radio emission from SN 2012au was not dissimilar from other core-collapse supernovae despite its extraordinary optical properties, and that the evolution of the SN 2012au progenitor star was relatively quiet, marked with a steady mass loss, during the final years preceding explosion.

  13. Experience of Multisensory Environments in Public Space among People with Visual Impairment

    Directory of Open Access Journals (Sweden)

    Gavin R. Jenkins

    2015-07-01

    Full Text Available This qualitative study explored the role of sensory characteristics embedded in the built environment and whether they support or hinder people with visual impairment in their use of public spaces. An online survey link was e-mailed to the presidents and committee members of each state’s chapters and associations of the National Federation of the Blind in the United States, resulting in 451 direct invitations to participate. Written responses of the survey questions from 48 respondents with visual impairment were analyzed. Three main themes: Barriers, Supporters, and Context-Dependence emerged from the respondents’ experience of multisensory characteristics within the built environment. The four subthemes subsumed in Barriers were: (1 Population specific design, (2 Extreme sensory backgrounds, (3 Uneven ground surfaces and objects, and (4 Inconsistent lighting. For Supporters, respondents provided specific examples of various sensory characteristics in built environments, including audible cues and echoes, smells, tactile quality of the ground surface, and temperature. Context-Dependence referred to the effects of sensory characteristics embedded in public spaces depending on one’s vision condition, the proximity to the sensory cues and the purpose of the activities one was performing at that moment. Findings provide occupational therapy practitioners an in-depth understanding of the transactional relationship between embedded sensory characteristics in the built environment, occupations, and people with visual impairment in order to make appropriate modifications or removal of barriers that affect occupational performance and engagement. Suggestions for occupational therapists as well as architects, designers, planners, policy makers/legislators related to functional sensory cues in the design of built environments were provided to increase accessibility in the use of public spaces by people with visual impairment.

  14. Global Indicators Analysis and Consultancy Experience Insights into Correlation between Entrepreneurial Activities and Business Environment

    Directory of Open Access Journals (Sweden)

    Jovan Krivokapić

    2015-02-01

    Full Text Available Many researches and practical experiences clearly indicate the existence of a strong relationship between entrepreneurial activities and the business environment in which these activities are initiated. Although this topic has been quite ignored until the late twentieth century, a lot of studies and consulting practice have contributed to the fact that there are now a number of theories concerning mentioned correlation. These theories aim to offer a model that would provide better utilization of the possibilities from the business environment which could be very important for the development from both macroeconomic and microeconomic aspects. An increasing number of articles on this topic says enough about its importance, and numerous researches by many reputable globally recognized institutions go in favor of this claim. There are many indicators that observe the economic situation in a country or a region from different aspects, so the analyses of these indicators make it possible to determine the specific relationships between entrepreneurial activities and the local and the global business environment. Given the complexity of these relations, the impact cannot be observed partially, without taking into consideration other important factors, but more detailed analyses, however, result in some useful conclusions, which in the proper context can have a positive impact on many economic factors. It is very important to emphasize the fact that the correlation between the business environment and entrepreneurial activities is bidirectional, since this influence is mutual, so that changes in one of these factors can and usually cause some modifications in the other. Frequent series of such iterations actually lead to changes in the business environment, while entrepreneurial activity changes its shape and affects the economy of a country or a region, which is of particular importance for its competitiveness in the era of globalization.

  15. Experience of Multisensory Environments in Public Space among People with Visual Impairment.

    Science.gov (United States)

    Jenkins, Gavin R; Yuen, Hon K; Vogtle, Laura K

    2015-07-23

    This qualitative study explored the role of sensory characteristics embedded in the built environment and whether they support or hinder people with visual impairment in their use of public spaces. An online survey link was e-mailed to the presidents and committee members of each state's chapters and associations of the National Federation of the Blind in the United States, resulting in 451 direct invitations to participate. Written responses of the survey questions from 48 respondents with visual impairment were analyzed. Three main themes: Barriers, Supporters, and Context-Dependence emerged from the respondents' experience of multisensory characteristics within the built environment. The four subthemes subsumed in Barriers were: (1) Population specific design, (2) Extreme sensory backgrounds, (3) Uneven ground surfaces and objects, and (4) Inconsistent lighting. For Supporters, respondents provided specific examples of various sensory characteristics in built environments, including audible cues and echoes, smells, tactile quality of the ground surface, and temperature. Context-Dependence referred to the effects of sensory characteristics embedded in public spaces depending on one's vision condition, the proximity to the sensory cues and the purpose of the activities one was performing at that moment. Findings provide occupational therapy practitioners an in-depth understanding of the transactional relationship between embedded sensory characteristics in the built environment, occupations, and people with visual impairment in order to make appropriate modifications or removal of barriers that affect occupational performance and engagement. Suggestions for occupational therapists as well as architects, designers, planners, policy makers/legislators related to functional sensory cues in the design of built environments were provided to increase accessibility in the use of public spaces by people with visual impairment.

  16. An optoelectronic detecting based environment perception experiment for primer students using multiple-layer laser scanner

    Science.gov (United States)

    Wang, Shifeng; Wang, Rui; Zhang, Pengfei; Dai, Xiang; Gong, Dawei

    2017-08-01

    One of the motivations of OptoBot Lab is to train primer students into qualified engineers or researchers. The series training programs have been designed by supervisors and implemented with tutoring for students to test and practice their knowledge from textbooks. An environment perception experiment using a 32 layers laser scanner is described in this paper. The training program design and laboratory operation is introduced. The four parts of the experiments which are preparation, sensor calibration, 3D space reconstruction, and object recognition, are the participating students' main tasks for different teams. This entire program is one of the series training programs that play significant role in establishing solid research skill foundation for opto-electronic students.

  17. The development of a distributed computing environment for the design and modeling of plasma spectroscopy experiments

    International Nuclear Information System (INIS)

    Nash, J.K.; Eme, W.G.; Lee, R.W.; Salter, J.M.

    1994-10-01

    The design and analysis of plasma spectroscopy experiments can be significantly complicated by relatively routine computational tasks arising from the massive amount of data encountered in the experimental design and analysis stages of the work. Difficulties in obtaining, computing, manipulating and visualizing the information represent not simply an issue of convenience -- they have a very real limiting effect on the final quality of the data and on the potential for arriving at meaningful conclusions regarding an experiment. We describe ongoing work in developing a portable UNIX environment shell with the goal of simplifying and enabling these activities for the plasma-modeling community. Applications to the construction of atomic kinetics models and to the analysis of x-ray transmission spectroscopy will be shown

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

    Science.gov (United States)

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

    2012-01-01

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

  19. Understanding the Influence of Environment on Adults’ Walking Experiences: A Meta-Synthesis Study

    Directory of Open Access Journals (Sweden)

    Sara Dadpour

    2016-07-01

    Full Text Available The environment has an important impact on physical activity, especially walking. The relationship between the environment and walking is not the same as for other types of physical activity. This study seeks to comprehensively identify the environmental factors influencing walking and to show how those environmental factors impact on walking using the experiences of adults between the ages of 18 and 65. The current study is a meta-synthesis based on a systematic review. Seven databases of related disciplines were searched, including health, transportation, physical activity, architecture, and interdisciplinary databases. In addition to the databases, two journals were searched. Of the 11,777 papers identified, 10 met the eligibility criteria and quality for selection. Qualitative content analysis was used for analysis of the results. The four themes identified as influencing walking were “safety and security”, “environmental aesthetics”, “social relations”, and “convenience and efficiency”. “Convenience and efficiency” and “environmental aesthetics” could enhance the impact of “social relations” on walking in some aspects. In addition, “environmental aesthetics” and “social relations” could hinder the influence of “convenience and efficiency” on walking in some aspects. Given the results of the study, strategies are proposed to enhance the walking experience.

  20. Nursing care in a high-technological environment: Experiences of critical care nurses.

    Science.gov (United States)

    Tunlind, Adam; Granström, John; Engström, Åsa

    2015-04-01

    Management of technical equipment, such as ventilators, infusion pumps, monitors and dialysis, makes health care in an intensive care setting more complex. Technology can be defined as items, machinery and equipment that are connected to knowledge and management to maximise efficiency. Technology is not only the equipment itself, but also the knowledge of how to use it and the ability to convert it into nursing care. The aim of this study is to describe critical care nurses' experience of performing nursing care in a high technology healthcare environment. Qualitative, personal interviews were conducted during 2012 with eight critical care nurses in the northern part of Sweden. Interview transcripts were analysed using qualitative content analysis. Three themes with six categories emerged. The technology was described as a security that could facilitate nursing care, but also one that could sometimes present obstacles. The importance of using the clinical gaze was highlighted. Nursing care in a high technological environment must be seen as multi-faceted when it comes to how it affects CCNs' experience. The advanced care conducted in an ICU could not function without high-tech equipment, nor could care operate without skilled interpersonal interaction and maintenance of basal nursing. That technology is seen as a major tool and simultaneously as a barrier to patient-centred care. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Game controller modification for fMRI hyperscanning experiments in a cooperative virtual reality environment.

    Science.gov (United States)

    Trees, Jason; Snider, Joseph; Falahpour, Maryam; Guo, Nick; Lu, Kun; Johnson, Douglas C; Poizner, Howard; Liu, Thomas T

    2014-01-01

    Hyperscanning, an emerging technique in which data from multiple interacting subjects' brains are simultaneously recorded, has become an increasingly popular way to address complex topics, such as "theory of mind." However, most previous fMRI hyperscanning experiments have been limited to abstract social interactions (e.g. phone conversations). Our new method utilizes a virtual reality (VR) environment used for military training, Virtual Battlespace 2 (VBS2), to create realistic avatar-avatar interactions and cooperative tasks. To control the virtual avatar, subjects use a MRI compatible Playstation 3 game controller, modified by removing all extraneous metal components and replacing any necessary ones with 3D printed plastic models. Control of both scanners' operation is initiated by a VBS2 plugin to sync scanner time to the known time within the VR environment. Our modifications include:•Modification of game controller to be MRI compatible.•Design of VBS2 virtual environment for cooperative interactions.•Syncing two MRI machines for simultaneous recording.

  2. A Mid-Infrared Study of the Circumstellar Dust Composition and Phase Behavior of Oxygen-rich Mira Variables

    Science.gov (United States)

    Guth, Tina

    2017-08-01

    The elements essential as building blocks of life, such as carbon and oxygen, have long been considered to come from exploding stars, known as supernovae. However, in the last several years, observations obtained with improved telescopes and instruments have shown that these heavier elements, i.e. elements beyond helium, are readily found in mass-loss products of stars called Asymptotic Giant Branch (AGB) stars. The sub-category of AGB stars that have regular pulsation periods of 200 - 500 days, called Mira variables, are of particular interest. These regular pulsators are quite bright in both the optical and infrared wavelengths, and exhibit large changes in magnitude that are easily observable. Studying their circumstellar dust environment allows astronomers to determine the presence of compounds, such as silicates and oxides, which are indicative of common elements found on Earth - oxygen, carbon, and silicon. Mira variables are dynamic stars, which implies that the circumstellar dust composition should change as the star goes through its pulsation cycle. In order to study the dust behavior with pulsational phase, repeated infrared observations were obtained with the Spitzer Space Telescope. This infrared, space-based telescope was launched in 2003 and carries the Infrared Spectrograph (IRS) instrument, which produces brightness versus wavelength, i.e. a spectrum (Houck et al., 2004). Due to the pulsation period of these stars, they were observed approximately monthly during the campaign run in 2008-9. This work focuses on the high-resolution data over a wavelength range of 9.8 - 40 microns because it provides a high signal-to-noise ratio and examines the part of the spectrum where dust features are most apparent. The full dataset obtained with Spitzer consists of 25 stars and covers nearly 100 spectra spanning all three chemical subclasses, however the focus of this dissertation is on investigating the dusty environment of oxygen-rich Mira variables. First, an

  3. Relations Between Self-Reported and Linguistic Monitoring Assessments of Affective Experience in an Extreme Environment.

    Science.gov (United States)

    Smith, Nathan

    2018-03-01

    Approaches for monitoring psychosocial health in challenging environments are needed to maintain the performance and safety of personnel. The purpose of the present research was to examine the relationship between 2 candidate methods (self-reported and linguistics) for monitoring affective experience during extreme environment activities. A single-subject repeated-measures design was used in the present work. The participant was a 46-year-old individual scheduled to complete a self-supported ski expedition across Arctic Greenland. The expedition lasted 28 days, and conditions included severe cold, low stimulation, whiteouts, limited habitability, and threats to life and limb. During the expedition, the participant completed a daily self-report log including assessment of psychological health (perceptions of control and affect) and a video diary (emotion). Video diary entries were subjected to linguistic inquiry and word count analyses before the links between self-report and linguistic data across the expedition period were tested. Similarities in the pattern of self-reported and linguistic assessments emerged across the expedition period. A number of predictable correlations were identified between self-reported and linguistic assessments of affective/emotional experience. Overall, there was better agreement between self-reports and linguistic analytics for indicators of negative affect/emotion. Future research should build on this initial study to further test the links between self-reported affect and emotional states monitored via linguistics. This could help develop methods for monitoring psychological health in extreme environments and support organizational decision making. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  4. The limits of extremophilic life expanded under extraterrestrial environment-simulated experiments

    Science.gov (United States)

    Lage, C.; Dalmaso, G.; Teixeira, L.; Bendia, A.; Rosado, A.

    2012-09-01

    Astrobiology is a brand new area of science that seeks to understand the origin and dynamics of life in the universe. Several hypotheses to explain life in the cosmic context have been developed throughout human history, but only now technology has allowed many of them to be tested. Laboratory experiments have been able to show how chemical elements essential to life, carbon, nitrogen, oxygen and hydrogen combine in biologically important compounds. Interestingly, these compounds are found universally. As these compounds were combined to the point of originating cells and complex organisms is still a challenge to be unveiled by science. However, our 4.5 billion years-old solar system was born within a 10-billion years-old universe. Thus, simple cells like microorganisms may have had time to form in planets older than ours or other suitable molecular places in the universe. One hypothesis to explain the origin of life on Earth is called panspermia, which predicts that microbial life could have been formed in the universe billions of years ago, traveling between planets, and inseminating units of life that could have become more complex in habitable planets like ours. A project designed to test the viability of extremophile microorganisms exposed to simulated extraterrestrial environments is ongoing at the Carlos Chagas Filho Institute of Biophysics to test whether microbial life could withstand those inhospitable environments. Ultra-resistant (known or novel ones) microorganisms collected from terrestrial extreme environments, extremophiles, have been exposed to intense radiation sources simulating solar radiation (at synchrotron accelerators), capable of emitting in a few hours radiation equivalent of million years accumulated doses. The results obtained in these experiments reveal the interesting possibility of the existence of microbial life beyond Earth.

  5. Built environment affecting visitors' walking choice in commercial areas? - A study with GPS experiments

    Science.gov (United States)

    Hahm, Y.; Yoon, H.

    2016-12-01

    Retail location is one of the most critical factors explaining the success of store operations. Store owners prefer to choose locations with high visibility and convenient transportation, which might be likely reasons for higher pedestrian volume, hence larger chance to capture impulse shoppers, resulting in more profits. While researches have focused on discerning relationship between pedestrian route choice and physical environments via indirect measures such as survey questionnaire and interviews, recent technologies such as Global Positioning System (GPS) enables collecting direct and precise waking route data. In this study, we investigate the physical environments in which pedestrians prefer to be in commercial district, and further analyze if such locations encompass stores with higher store revenues. The primary method is GPS experiment and travel diary for over hundred visitors of the study site, Hongik University commercial areas in Seoul, South Korea, and statistical analysis, Structural Equation Model (SEM). With SEM, we could assess endogenous latent variables indicating built environments, such as Density, Diversity, Destination Accessibility, Design, and Retail Attraction, and exogenous latent variable, the pedestrian walking choice, based on the observation of pedestrian volume and walking speed. Observed variables include the number of stores, building uses, kind of retail, and pedestrian volume, and walking speed. This research will shed light on planning commercial districts, emphasizing the role of pedestrian walking in the success of retail business, and providing a clue on how to encourage pedestrian visitation by improving physical environment. This work is supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (No. 2015R1C1A2A01055615)

  6. The Influence of Trainee Gaming Experience and Computer Self-Efficacy on Learner Outcomes of Videogame-Based Learning Environments

    National Research Council Canada - National Science Library

    Orvis, Karin A; Orvis, Kara L; Belanich, James; Mullin, Laura N

    2005-01-01

    .... The purpose of the current research was to investigate the influence of two trainee characteristics, prior videogame experience and computer self-efficacy, on learner outcomes of a videogame-based training environment...

  7. MxCuBE: a synchrotron beamline control environment customized for macromolecular crystallography experiments

    International Nuclear Information System (INIS)

    Gabadinho, José; Beteva, Antonia; Guijarro, Matias; Rey-Bakaikoa, Vicente; Spruce, Darren

    2010-01-01

    MxCuBE is a beamline control environment optimized for the needs of macromolecular crystallography. This paper describes the design of the software and the features that MxCuBE currently provides. The design and features of a beamline control software system for macromolecular crystallography (MX) experiments developed at the European Synchrotron Radiation Facility (ESRF) are described. This system, MxCuBE, allows users to easily and simply interact with beamline hardware components and provides automated routines for common tasks in the operation of a synchrotron beamline dedicated to experiments in MX. Additional functionality is provided through intuitive interfaces that enable the assessment of the diffraction characteristics of samples, experiment planning, automatic data collection and the on-line collection and analysis of X-ray emission spectra. The software can be run in a tandem client-server mode that allows for remote control and relevant experimental parameters and results are automatically logged in a relational database, ISPyB. MxCuBE is modular, flexible and extensible and is currently deployed on eight macromolecular crystallography beamlines at the ESRF. Additionally, the software is installed at MAX-lab beamline I911-3 and at BESSY beamline BL14.1

  8. Perception Shapes Experience: The Influence of Actual and Perceived Classroom Environment Dimensions on Girls' Motivations for Science

    Science.gov (United States)

    Spearman, Juliette; Watt, Helen M. G.

    2013-01-01

    The classroom environment influences students' academic outcomes, but it is often students' perceptions that shape their classroom experiences. Our study examined the extent to which observed classroom environment features shaped perceptions of the classroom, and explained levels of, and changes in, girls' motivation in junior secondary school…

  9. The South African Military Nursing College Pupil Enrolled Nurses’ experiences of the clinical learning environment

    Directory of Open Access Journals (Sweden)

    Ernestina M. Caka

    2013-06-01

    Full Text Available The study focused on the clinical learning experiences of Pupil Enrolled Nurses (PENs within the military health service. The purpose of the research was to explore and describe the learning experiences of PENs within the Military health clinical learning environment. An explorative, descriptive, contextual design which is qualitative in nature was used to guide the study. The military as a training institution prides itself on preparing nurses both as soldiers and nurses, this could be both challenging and exasperating for students, as the scopes are diverse. Being notably very hierarchical, the military’s rules constantly take precedence over nursing rules. For the duration of nursing training, students are allocated in the clinical learning area to acquire competencies such as problem solving, cognitive and psychomotor skills (Kuiper & Pesut 2003:383. Students learn how to merge theory and practice and apply theories in the practical sense. This is however, not done in isolation from the military codes, as they are intertwined. Attendance of military parades and drills are incorporated during this phase. This could create missed opportunities from the clinical learning as students are expected to leave the clinical setting for this purpose. Three focus group sessions were conducted and the experiences of the students, as narrated by themselves, yielded valuable insights. The researcher wrote field notes and assisted with the management of the audio tapes for easy retrieval of information. Data was analysed by the researcher, independent of the cocoder. Two themes relating to the PENs’ learning experiences emerged from the data analysed: (1 facilitators of clinical learning, (2 and barriers to clinical learning. The findings obtained depicted those factors which facilitated and obstructed student learning. These findings made it possible for the researcher to make recommendations concerning positive interventions which could be taken to

  10. Relationships between middle childhood outdoor experiences and an adult individual's knowledge of the environment

    Science.gov (United States)

    Gillette, Brandon A.

    During the last several decades, the nature of childhood has changed. There is not much nature in it anymore. Numerous studies in environmental education, environmental psychology, and conservation psychology show that the time children spend outdoors encourages healthy physical development, enriches creativity and imagination, and enhances classroom performance. Additional research shows that people's outdoor experiences as children, and adults can lead to more positive attitudes and behavior towards the environment, along with more environmental knowledge with which to guide public policy decisions. The overall purpose of this study was to examine the effect of middle childhood (age 6-11) outdoor experiences on an individual's current knowledge of the environment. This correlational study evaluated the following potential relationships: 1) The effect of "outdoorsiness" (defined as a fondness or enjoyment of the outdoors and related activities) on an individual's environmental knowledge; 2) The effect of gender on an individual's level of outdoorsiness; 3) The effect of setting (urban, suburban, rural, farm) on an individual's level of outdoorsiness and environmental knowledge; 4) The effect of formal [science] education on an individual's level of outdoorsiness and environmental knowledge; and 5) The effect of informal, free-choice learning on an individual's level of outdoorsiness and environmental knowledge. Outdoorsiness was measured using the Natural Experience Scale (NES), which was developed through a series of pilot surveys and field-tested in this research study. Participants included 382 undergraduate students at the University of Kansas with no preference or bias given to declared or undeclared majors. The information from this survey was used to analyze the question of whether outdoor experiences as children are related in some way to an adult's environmental knowledge after accounting for other factors of knowledge acquisition such as formal education

  11. Experiences from Real-World Deployment of Context-Aware Technologies in a Hospital Environment

    DEFF Research Database (Denmark)

    Bardram, Jakob Eyvind; Hansen, Thomas Riisgaard; Mogensen, Martin

    2006-01-01

    and discuss our experiences from an ongoing deployment of a suite of context-aware technologies and applications in a hospital environment, including a context-awareness infrastructure, a location tracking system, and two context-aware applications running on interactive wall displays and mobile phones. Based......Context-aware computing is a central concept in ubiquitous computing and many suggestions for context-aware technologies and applications have been proposed. There is, however, little evidence on how these concepts and technologies play out in a real-world setting. In this paper we describe...... on an analysis of the use of these systems, we observe that many of the ideas behind context-aware computing are valid, and that the context-aware applications are useful for clinicians in their work. By reflecting on the nature of the designed context-aware technologies, we present a model which states...

  12. Technetium-99 behavior in the terrestrial environment. Field observations and radiotracer experiments

    International Nuclear Information System (INIS)

    Tagami, Keiko

    2003-01-01

    Obtaining data on 99 Tc in the rice paddy field environment is important because Tc is a redox sensitive element. The behavior of Tc is expected to be different under upland field and rice paddy field conditions since the redox conditions in the soil environment differ. However, most of the data on the nuclide behavior in soil were obtained under upland field conditions. To understand the global fallout 99 Tc distributions in soil samples collected in Japan, a simple and rapid separation method was developed in order to determine low-levels of 99 Tc in soil samples by an inductively coupled plasma mass spectrometry. Also, radiotracer experiments using soils under aerobic and anaerobic conditions were carried out to clarify the Tc behavior under paddy field conditions. The results of determination of global fallout 99 Tc in Japanese soils indicated that the radionuclide had been accumulating in rice paddy fields. The mechanisms can be explained by the immobilization of Tc in soil under anaerobic conditions. From the radiotracer experiments, it was clear that under waterlogged conditions, the highly mobile TcO 4 - in soil was readily changed to other immobilized forms, such as TcO 2 , TcS 2 and organically bound forms. To this immobilization, the microbial activity seemed to have an important role in Tc sorption reactions. When the soil, which was once kept in anaerobic conditions, was air-dried again and kept in aerobic conditions, the chemical forms of immobilized Tc did not change remarkably. Interestingly, the similar Tc behavior was observed in a real wet forest near the Chernobyl Reactor. (author)

  13. Managing the environment and metamorphoses of the State: the French experience

    Directory of Open Access Journals (Sweden)

    Cécilia Claeys-Mekdade

    2007-01-01

    Full Text Available This article examines the evolution of the State’s role in management of the environment. The French experience, characterised by a highly-centralised State, presents researchers with a situation where anypermanence, like any change, tends to be extreme. Therefore it acts as a starting point for our analysis of changes in the State’s role in the management of nature, which was formerly considered as a resource to be exploited, and is now redefined as an environment to be protected. In particular, diachronic analysis enables us to grasp the dynamics of these social changes. On the basis of an interdisciplinary exchange between a historian and a sociologist, this article suggests that we should qualify theories of the disappearance of the State by giving ourselves the means to differentiate, in management of theenvironment, what is new and what is not, by highlighting the capacity for “integration of criticism” (BOLTANSKI; CHIAPELLO, 1999 by institutions. The environment is an instrument of hybridisation that questions old dichotomies: between nature and culture, between local and national, between the particular and the general, between vernacular knowledge and scientific knowledge. This questioning tends to deprive science and politics of their respective monopolies as representatives of nature and of society. Against this background, the central State becomes a manager of socio-natural diversity, thetechnocratic State gives a voice to local know-how, and the State concedes a certain plurality to the general public interest of which it no longer has quite a complete monopoly. The State is no longer quite what it was, in its role and its functioning, but the State endures. Thus, the society is changing, but the categories of the XX° century are not totally obsolete yet.

  14. Gene-environment interaction in Major Depression: focus on experience-dependent biological systems

    Directory of Open Access Journals (Sweden)

    Nicola eLopizzo

    2015-05-01

    Full Text Available Major Depressive Disorder (MDD is a multifactorial and polygenic disorder, where multiple and partially overlapping sets of susceptibility genes interact each other and with the environment, predisposing individuals to the development of the illness. Thus, MDD results from a complex interplay of vulnerability genes and environmental factors that act cumulatively throughout individual's lifetime. Among these environmental factors, stressful life experiences, especially those occurring early in life, have been suggested to exert a crucial impact on brain development, leading to permanent functional changes that may contribute to life long risk for mental health outcomes. In this review we will discuss how genetic variants (polymorphisms, SNPs within genes operating in neurobiological systems that mediate stress response and synaptic plasticity, can impact, by themselves, the vulnerability risk for MDD; we will also consider how this MDD risk can be further modulated when gene X environment interaction is taken into account. Finally, we will discuss the role of epigenetic mechanisms, and in particular of DNA methylation and miRNAs expression changes, in mediating the effect of the stress on the vulnerability risk to develop MDD. Taken together, in this review we aim to underlie the role of genetic and epigenetic processes involved in stress and neuroplasticity related biological systems on development of MDD after exposure to early life stress, thereby building the basis for future research and clinical interventions.

  15. Hypersonic Engine Leading Edge Experiments in a High Heat Flux, Supersonic Flow Environment

    Science.gov (United States)

    Gladden, Herbert J.; Melis, Matthew E.

    1994-01-01

    A major concern in advancing the state-of-the-art technologies for hypersonic vehicles is the development of an aeropropulsion system capable of withstanding the sustained high thermal loads expected during hypersonic flight. Three aerothermal load related concerns are the boundary layer transition from laminar to turbulent flow, articulating panel seals in high temperature environments, and strut (or cowl) leading edges with shock-on-shock interactions. A multidisciplinary approach is required to address these technical concerns. A hydrogen/oxygen rocket engine heat source has been developed at the NASA Lewis Research Center as one element in a series of facilities at national laboratories designed to experimentally evaluate the heat transfer and structural response of the strut (or cowl) leading edge. A recent experimental program conducted in this facility is discussed and related to cooling technology capability. The specific objective of the experiment discussed is to evaluate the erosion and oxidation characteristics of a coating on a cowl leading edge (or strut leading edge) in a supersonic, high heat flux environment. Heat transfer analyses of a similar leading edge concept cooled with gaseous hydrogen is included to demonstrate the complexity of the problem resulting from plastic deformation of the structures. Macro-photographic data from a coated leading edge model show progressive degradation over several thermal cycles at aerothermal conditions representative of high Mach number flight.

  16. Early Childhood Educators' Experiences in Their Work Environments: Shaping (Im)possible Ways of Being an Educator?

    Science.gov (United States)

    Cumming, Tamara

    2015-01-01

    The purpose of this article is to explore the complex interrelations between educators' work environments and their experiences as an entryway for thinking differently about workforce stability and sustainability. Concepts of macro- and micropolitics (drawn from the work of Deleuze and Guattari) are used to explore one educator's experiences in…

  17. Environment

    International Nuclear Information System (INIS)

    McIntyre, A.D.; Turnbull, R.G.H.

    1992-01-01

    The development of the hydrocarbon resources of the North Sea has resulted in both offshore and onshore environmental repercussions, involving the existing physical attributes of the sea and seabed, the coastline and adjoining land. The social and economic repercussions of the industry were equally widespread. The dramatic and speedy impact of the exploration and exploitation of the northern North Sea resources in the early 1970s, on the physical resources of Scotland was quickly realised together with the concern that any environmental and social damage to the physical and social fabric should be kept to a minimum. To this end, a wide range of research and other activities by central and local government, and other interested agencies was undertaken to extend existing knowledge on the marine and terrestrial environments that might be affected by the oil and gas industry. The outcome of these activities is summarized in this paper. The topics covered include a survey of the marine ecosystems of the North Sea, the fishing industry, the impact of oil pollution on seabirds and fish stocks, the ecology of the Scottish coastline and the impact of the petroleum industry on a selection of particular sites. (author)

  18. On the potential for using immersive virtual environments to support laboratory experiment contextualisation

    Science.gov (United States)

    Machet, Tania; Lowe, David; Gütl, Christian

    2012-12-01

    This paper explores the hypothesis that embedding a laboratory activity into a virtual environment can provide a richer experimental context and hence improve the understanding of the relationship between a theoretical model and the real world, particularly in terms of the model's strengths and weaknesses. While an identified learning objective of laboratories is to support the understanding of the relationship between models and reality, the paper illustrates that this understanding is hindered by inherently limited experiments and that there is scope for improvement. Despite the contextualisation of learning activities having been shown to support learning objectives in many fields, there is traditionally little contextual information presented during laboratory experimentation. The paper argues that the enhancing laboratory activity with contextual information affords an opportunity to improve students' understanding of the relationship between the theoretical model and the experiment (which is effectively a proxy for the complex real world), thereby improving their understanding of the relationship between the model and reality. The authors propose that these improvements can be achieved by setting remote laboratories within context-rich virtual worlds.

  19. Urban Field Experiences for Undergraduate Liberal Arts Students: Using Compromised Environments as Living Laboratories

    Science.gov (United States)

    MacAvoy, S. E.; Knee, K.

    2015-12-01

    While urban environments may lack the beauty of relatively pristine field sites, they can be used to deliver an effective demonstration of actual environmental damage. Students demanding applied field experiences from their undergraduate environmental science programs can be well served in urban settings. Here, we present strategies for integrating degraded urban systems into the undergraduate field experience. Urban locations provide an opportunity for a different type of local "field-work" than would otherwise be available. In the upper-level undergraduate Environmental Methods class, we relied on a National Park area located a 10-minute walk from campus for most field exercises. Activities included soil analysis, measuring stream flow and water quality parameters, dendrochronology, and aquatic microbe metabolism. In the non-majors class, we make use of our urban location to contrast water quality in parks and highly channelized urban streams. Students spend labs immersed in streams and wetlands heavily impacted by the urban runoff their city generates. Here we share lesson plans and budgets for field activities that can be completed during a class period of 2.5 hours with a $75 course fee, show how these activities help students gain quantitative competency.

  20. Use of Unpalatable Forages by Ruminants: The Influence of Experience with the Biophysical and Social Environment

    Directory of Open Access Journals (Sweden)

    Roberto A. Distel

    2018-04-01

    Full Text Available Unpalatable forage resources (low nutrient density, potentially toxic metabolites are widespread and represent a challenge for ruminant nutrition, health, and welfare. Our objective was to synthesize the role of biophysical and social experience on the use of unpalatable forages by ruminants, and highlight derived behavioural solutions for the well-being of soils, plants, and animals. Environmental experiences early in life modulate gene expression and promote learning, which alters morpho-physiological and psychological mechanisms that modify behavioural responses and change food and habitat selection. In this process, ruminants can become better adapted to the habitat where they are reared. Moreover, experiential learning provides flexibility in diet selection, which is critical for changing foraging environments. Learned associations between unpalatable and palatable foods, if ingested in appropriate amounts, sequence, and close temporal association, induce the development of preference for the former type of food. In this way, a more uniform use of resources can be achieved from the landscape level down to the individual plant, with the associated benefits to ecosystem integrity and stability. Ruminants can also learn the medicinal benefits of ingesting foods with toxins (e.g., condensed tannins and saponins with antiparasitic properties. This knowledge on behavioural processes can be translated into behavioural applications that provide low-cost solutions to many challenges that producers face in managing sustainable livestock production systems.

  1. Toward autonomous rotorcraft flight in degraded visual environments: experiments and lessons learned

    Science.gov (United States)

    Stambler, Adam; Spiker, Spencer; Bergerman, Marcel; Singh, Sanjiv

    2016-05-01

    Unmanned cargo delivery to combat outposts will inevitably involve operations in degraded visual environments (DVE). When DVE occurs, the aircraft autonomy system needs to be able to function regardless of the obscurant level. In 2014, Near Earth Autonomy established a baseline perception system for autonomous rotorcraft operating in clear air conditions, when its m3 sensor suite and perception software enabled autonomous, no-hover landings onto unprepared sites populated with obstacles. The m3's long-range lidar scanned the helicopter's path and the perception software detected obstacles and found safe locations for the helicopter to land. This paper presents the results of initial tests with the Near Earth perception system in a variety of DVE conditions and analyzes them from the perspective of mission performance and risk. Tests were conducted with the m3's lidar and a lightweight synthetic aperture radar in rain, smoke, snow, and controlled brownout experiments. These experiments showed the capability to penetrate through mild DVE but the perceptual capabilities became degraded with the densest brownouts. The results highlight the need for not only improved ability to see through DVE, but also for improved algorithms to monitor and report DVE conditions.

  2. Interpolation Environment of Tensor Mathematics at the Corpuscular Stage of Computational Experiments in Hydromechanics

    Science.gov (United States)

    Bogdanov, Alexander; Degtyarev, Alexander; Khramushin, Vasily; Shichkina, Yulia

    2018-02-01

    Stages of direct computational experiments in hydromechanics based on tensor mathematics tools are represented by conditionally independent mathematical models for calculations separation in accordance with physical processes. Continual stage of numerical modeling is constructed on a small time interval in a stationary grid space. Here coordination of continuity conditions and energy conservation is carried out. Then, at the subsequent corpuscular stage of the computational experiment, kinematic parameters of mass centers and surface stresses at the boundaries of the grid cells are used in modeling of free unsteady motions of volume cells that are considered as independent particles. These particles can be subject to vortex and discontinuous interactions, when restructuring of free boundaries and internal rheological states has place. Transition from one stage to another is provided by interpolation operations of tensor mathematics. Such interpolation environment formalizes the use of physical laws for mechanics of continuous media modeling, provides control of rheological state and conditions for existence of discontinuous solutions: rigid and free boundaries, vortex layers, their turbulent or empirical generalizations.

  3. Deep Sea Shell Taphonomy: Interactive benthic experiments in hydrate environments of Barkley Canyon, Ocean Networks Canada.

    Science.gov (United States)

    Best, Mairi; Purser, Autun

    2015-04-01

    In order to quantify and track the rates and processes of modification of biogenic carbonate in gas hydrate environments, and their possible environmental/ecological correlates, ongoing observations of experimentally deployed specimens are being made using a remotely controlled crawler with camera and sensors. The crawler is connected to NEPTUNE Canada, an 800km, 5-node, regional cabled ocean network across the northern Juan de Fuca Plate, northeastern Pacific, part of Ocean Networks Canada. One of 15 study areas is an environment of exposed hydrate mounds along the wall of Barkley Canyon, at ˜865m water depth. This is the home of a benthic crawler developed by Jacobs University of Germany, who is affectionately known as Wally. Wally is equipped with a range of sensors including cameras, methane sensor, current meter, fluorometer, turbidity meter, CTD, and a sediment microprofiler with probes for oxygen, methane, sulphide, pH, temperature, and conductivity. In conjunction with this sensor suite, a series of experiments have been designed to assess the cycling of biogenic carbon and carbonate in this complex environment. The biota range from microbes, to molluscs, to large fish, and therefore the carbon inputs include both a range of organic carbon compounds as well as the complex materials that are "biogenic carbonate". Controlled experimental specimens were deployed of biogenic carbonate (Mytilus edulis fresh shells) and cellulose (pieces of untreated pine lumber) that had been previously well characterized (photographed, weighed, and numbered, matching valves and lumber kept as controls). Deployment at the sediment/water interface was in such a way to maximize natural burial exhumation cycles but to minimize specimen interaction. 10 replicate specimens of each material were deployed in two treatments: 1) adjacent to a natural life and death assemblage of chemosynthetic bivalves and exposed hydrate on a hydrate mound and 2) on the muddy seafloor at a distance

  4. Predicting DUI decisions in different legal environments: investigating deterrence with a conjoint experiment.

    Science.gov (United States)

    Yao, Jie; Johnson, Mark B; Beck, Kenneth H

    2014-01-01

    Driving under the influence (DUI) enforcement practices and sanctions contribute differentially to the certainty, swiftness, and severity of punishment, which are the key components of general deterrence theory. This study used a conjoint experiment to understand the decision-making process of potential DUI offenders and tested how variation in enforcement and legal punishment affects drinking and driving decisions. It sought to verify and quantify the unique deterrent effects of certainty, severity, and swiftness and to predict the rates of drinking and driving in different legal environments. One hundred twenty-one college seniors and graduate students at the University of Maryland participated in the Web-based conjoint experiment. They were randomly assigned to 4 blocks, each of which included 9 hypothetical scenarios composed of different levels of DUI enforcement and penalties. Respondents were asked to state their likelihood of drinking and driving under each scenario, as well as their estimated chance of being caught by the police for DUI. Intensified enforcement, harsh jail penalty, and immediate long license suspension were found to be the strongest deterrents to drinking and driving. Alternative ways to get home were also important in reducing people's willingness to drive. These factors accounted for most of the attribute effect on the DUI decision, whereas delayed punishment due to judicial processing, fine penalty, and legal blood alcohol concentration (BAC) limit had negligible effects. For the personal characteristics, college seniors and those who had previously driven after drinking were more likely to choose to drink and drive, whereas those who expect a jail penalty for a DUI offense were less likely to drive. Our research confirmed and quantified certainty of punishment as the greatest deterrent to DUI, but it also indicated the equally important effect of a severe jail penalty. It provides evidence on the feasibility of using a conjoint

  5. A High-mass Protobinary System with Spatially Resolved Circumstellar Accretion Disks and Circumbinary Disk

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, S.; Kluska, J.; Kreplin, A.; Bate, M.; Harries, T. J.; Hone, E.; Anugu, A. [School of Physics, Astrophysics Group, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Hofmann, K.-H.; Weigelt, G. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Monnier, J. D. [Department of Astronomy, University of Michigan, 311 West Hall, 1085 South University Avenue, Ann Arbor, MI 48109 (United States); De Wit, W. J. [ESO, Alonso de Cordova 3107, Vitacura, Santiago 19 (Chile); Wittkowski, M., E-mail: skraus@astro.ex.ac.uk [ESO, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München (Germany)

    2017-01-20

    High-mass multiples might form via fragmentation of self-gravitational disks or alternative scenarios such as disk-assisted capture. However, only a few observational constraints exist on the architecture and disk structure of high-mass protobinaries and their accretion properties. Here, we report the discovery of a close (57.9 ± 0.2 mas = 170 au) high-mass protobinary, IRAS17216-3801, where our VLTI/GRAVITY+AMBER near-infrared interferometry allows us to image the circumstellar disks around the individual components with ∼3 mas resolution. We estimate the component masses to ∼20 and ∼18 M {sub ⊙} and find that the radial intensity profiles can be reproduced with an irradiated disk model, where the inner regions are excavated of dust, likely tracing the dust sublimation region in these disks. The circumstellar disks are strongly misaligned with respect to the binary separation vector, which indicates that the tidal forces did not have time to realign the disks, pointing toward a young dynamical age of the system. We constrain the distribution of the Br γ and CO-emitting gas using VLTI/GRAVITY spectro-interferometry and VLT/CRIRES spectro-astrometry and find that the secondary is accreting at a higher rate than the primary. VLT/NACO imaging shows L ′-band emission on (3–4)× larger scales than the binary separation, matching the expected dynamical truncation radius for the circumbinary disk. The IRAS17216-3801 system is ∼3× more massive and ∼5× more compact than other high-mass multiplies imaged at infrared wavelength and the first high-mass protobinary system where circumstellar and circumbinary dust disks could be spatially resolved. This opens exciting new opportunities for studying star–disk interactions and the role of multiplicity in high-mass star formation.

  6. Strengthening maintenance and reconstruction of scientific experiment building and creating a good working environment for scientific research and production

    International Nuclear Information System (INIS)

    Fu Jianping

    2005-01-01

    The quality of scientific experiment building directly influences the scientific research work and production. To create a good working environment for scientific research and production, it is necessary to strengthen the maintenance and reconstruction for old scientific experiment building. The paper briefly introduces the site supervisory work of maintaining and reconstructing old scientific experiment building in Beijing Research Institute of Uranium Geology, as well as some measures taken to ensure the project quality, and the reconstructed building. (authors)

  7. Radiative transfer in gray circumstellar dust envelopes: VY Canis Majoris revisited

    International Nuclear Information System (INIS)

    Schwartz, R.D.

    1975-01-01

    The circumstellar dust model for VY CMa proposed by Herbig is reinvestigated using a generalized form of Huang's theory of radiative transfer. The resultant envelope parameters and the emergent energy distribution are found to be insensitive to the choice of Eddington factor for a given envelope inner boundary temperature. Observed fluxes from 0.43 to 74 μ are incorporated into the model, and problems relating to grain emissivity for lambda>30 μ and grain survival at the indicated inner boundary temperature of 1855degreeK are discussed

  8. Direct imaging of extra-solar planetary systems with the Circumstellar Imaging Telescope (CIT)

    International Nuclear Information System (INIS)

    Terrile, R.J.

    1988-01-01

    In a joint study conducted by the Jet Propulsion Laboratory and the Perkin-Elmer Corporation it was found that an earth orbital, 1.5 meter diameter low scattered light coronagraphic telescope can achieve a broad range of scientific objectives including the direct detection of Jupiter-sized planets around the nearby stars. Recent major advances in the understanding of coronagraphic performance and in the field of super smooth mirror fabrication allow such an instrument to be designed and built within current technology. Such a project, called the Circumstellar Imaging Telescope (CIT), is currently being proposed. 10 references

  9. Perceptions of sexual harassment in Swedish high schools: experiences and school-environment problems.

    Science.gov (United States)

    Witkowska, Eva; Menckel, Ewa

    2005-02-01

    Sexual harassment in schools is recognized as a public-health problem detrimental to girls' psychosomatic health. This study examines the magnitude of sexual harassment and types of behaviours related to sexual harassment that female students are exposed to in a school environment, and their perceptions of them as problems in school. A random sample of 540 female high school students, from all over Sweden, responded to an anonymous self-report mail questionnaire consisting of items related to personal experiences of different behaviours related to sexual harassment during the previous school year. Sexual harassment was identified by 49% of the female students as a problem present in their schools. The most common types were verbal behaviours, such as: sexualized conversations, attractiveness rating, demeaning comments about gender, name-calling, and sexual personal comments. The most common non-verbal displays were: sexualized contact seeking and sexual looks. Behaviours in the sexual assault and teacher-to-student categories were less prevalent. In all four categories, the respondents who reported exposure to a particular behaviour were significantly more likely to identify that behaviour as a problem in their school. However, many non-exposed respondents also perceived such behaviours as problems in their school. Female high-school students in Sweden are exposed to a variety of inappropriate and/or unacceptable behaviours of a sexual nature, or based on sex, that may infringe their right to a supportive, respectful and safe learning environment or their dignity. Greater efforts are needed to analyse and prevent sexual harassment in schools.

  10. Older People's Experiences of Mobility and Mood in an Urban Environment: A Mixed Methods Approach Using Electroencephalography (EEG) and Interviews.

    Science.gov (United States)

    Tilley, Sara; Neale, Chris; Patuano, Agnès; Cinderby, Steve

    2017-02-04

    There are concerns about mental wellbeing in later life in older people as the global population becomes older and more urbanised. Mobility in the built environment has a role to play in improving quality of life and wellbeing, as it facilitates independence and social interaction. Recent studies using neuroimaging methods in environmental psychology research have shown that different types of urban environments may be associated with distinctive patterns of brain activity, suggesting that we interact differently with varying environments. This paper reports on research that explores older people's responses to urban places and their mobility in and around the built environment. The project aim was to understand how older people experience different urban environments using a mixed methods approach including electroencephalography (EEG), self-reported measures, and interview results. We found that older participants experience changing levels of "excitement", "engagement" and "frustration" (as interpreted by proprietary EEG software) whilst walking between a busy built urban environment and an urban green space environment. These changes were further reflected in the qualitative themes that emerged from transcribed interviews undertaken one week post-walk. There has been no research to date that has directly assessed neural responses to an urban environment combined with qualitative interview analysis. A synergy of methods offers a deeper understanding of the changing moods of older people across time whilst walking in city settings.

  11. Smoking environments in transition: the experiences of recent Chinese migrants to Canada.

    Science.gov (United States)

    Li, Jia; Collins, Damian

    2017-01-01

    International migrants experience first-hand differences between countries in terms of the social meanings, spatial regulation and prevalence of smoking. This research centred on the smoking-related perceptions, experiences and behaviours of recent migrants from China to Canada. Eight focus groups were held in Edmonton, Alberta, in July-October 2013 to explore migrants' understandings of the practices and meanings of smoking in both countries. There were 58 participants (37 non-smokers and 21 smokers), most of whom were international students. Qualitative content analysis of focus group transcripts was undertaken to identify key themes. Participants observed that smoking remains almost ubiquitous in China due to ineffective spatial restrictions and the social importance of smoking among men. By contrast, smoking bans in Canada were perceived as effective due to widespread compliance and expectations of enforcement. They were conscious that male smoking was both less prevalent and less socially valued in Canada; conversely, female smoking was perceived as more accepted in Canada than in China. There was broad agreement that smoking was tolerated in Canada, provided it occurred in appropriate places. Complying with widespread spatial restrictions brought about changes in smokers' behaviours: they smoked less often, and consumed fewer cigarettes. Because smoking was more difficult to perform, participants thought the Canadian context supported quitting. Non-smokers were enthusiastic about smoke-free environments in Canada, and had become acculturated to air that did not smell of smoke. These findings affirm the importance of comprehensive smoking bans, backed by enforcement, in contributing to the denormalisation of smoking and the protection of non-smokers. © 2015 The Authors. Health and Social Care in the Community Published by John Wiley & Sons Ltd.

  12. Nutrition Care Process Implementation: Experiences in Various Dietetics Environments in Sweden.

    Science.gov (United States)

    Lövestam, Elin; Boström, Anne-Marie; Orrevall, Ylva

    2017-11-01

    The Nutrition Care Process (NCP) and Nutrition Care Process Terminology (NCPT) are currently being implemented by nutrition and dietetics practitioners all over the world. Several advantages have been related to this implementation, such as consistency and clarity of dietetics-related health care records and the possibility to collect and research patient outcomes. However, little is known about dietitians' experiences of the implementation process. The aim of this qualitative study was to explore Swedish dietitians' experiences of the NCP implementation process in different dietetics environments. Thirty-seven Swedish dietitians from 13 different dietetics workplaces participated in seven focus group discussions that were audiotaped and carefully transcribed. A thematic secondary analysis was performed, after which all the discussions were re-read, following the implementation narrative from each workplace. In the analysis, The Promoting Action on Research Implementation in Health Services implementation model was used as a framework. Main categories identified in the thematic analysis were leadership and implementation strategy, the group and colleagues, the electronic health record, and evaluation. Three typical cases are described to illustrate the diversity of these aspects in dietetics settings: Case A represents a small hospital with an inclusive leadership style and discussion-friendly culture where dietitians had embraced the NCP/NCPT implementation. Case B represents a larger hospital with a more hierarchical structure where dietitians were more ambivalent toward NCP/NCPT implementation. Case C represents the only dietitian working at a small multiprofessional primary care center who received no dietetics-related support from management or colleagues. She had not started NCP/NCPT implementation. The diversity of dietetics settings and their different prerequisites should be considered in the development of NCP/NCPT implementation strategies. Tailored

  13. FIREX (Fire Influence on Regional and Global Environments Experiment): Measurements of Nitrogen Containing Volatile Organic Compounds

    Science.gov (United States)

    Warneke, C.; Schwarz, J. P.; Yokelson, R. J.; Roberts, J. M.; Koss, A.; Coggon, M.; Yuan, B.; Sekimoto, K.

    2017-12-01

    A combination of a warmer, drier climate with fire-control practices over the last century have produced a situation in which we can expect more frequent fires and fires of larger magnitude in the Western U.S. and Canada. There are urgent needs to better understand the impacts of wildfire and biomass burning (BB) on the atmosphere and climate system, and for policy-relevant science to aid in the process of managing fires. The FIREX (Fire Influence on Regional and Global Environment Experiment) research effort is a multi-year, multi-agency measurement campaign focused on the impact of BB on climate and air quality from western North American wild fires, where research takes place on scales ranging from the flame-front to the global atmosphere. FIREX includes methods development and small- and large-scale laboratory and field experiments. FIREX will include: emission factor measurements from typical North American fuels in the fire science laboratory in Missoula, Montana; mobile laboratory deployments; ground site measurements at sites influenced by BB from several western states. The main FIREX effort will be a large field study with multiple aircraft and mobile labs in the fire season of 2019. One of the main advances of FIREX is the availability of various new measurement techniques that allows for smoke evaluation in unprecedented detail. The first major effort of FIREX was the fire science laboratory measurements in October 2016, where a large number of previously understudied Nitrogen containing volatile organic compounds (NVOCs) were measured using H3O+CIMS and I-CIMS instruments. The contribution of NVOCs to the total reactive Nitrogen budget and the relationship to the Nitrogen content of the fuel are investigated.

  14. Radiative transfer in spherical circumstellar dust envelopes. III. Dust envelope models of some well known infrared stars

    International Nuclear Information System (INIS)

    Apruzese, J.P.

    1975-01-01

    The radiative transfer techniques described elsewhere by the author have been employed to construct dust envelope models of several well known infrared stars. The resulting calculations indicate that the infrared emissivity of circumstellar grains generally must be higher than that which many calculations of small nonsilicate grains yield. This conclusion is dependent to some degree on the (unknown) size of the stellar envelopes considered, but is quite firm in the case of the spatially resolved envelope of IRC+10216. Further observations of the spatial distribution of the infrared radiation from stellar envelopes will be invaluable in deciphering the properties of the circumstellar grains

  15. SiO maser emission as a density tracer of circumstellar envelopes

    Science.gov (United States)

    Stroh, Michael; Pihlstrom, Ylva; Sjouwerman, Lorant

    2018-06-01

    The circumstellar envelopes (CSEs) of evolved stars offer a method to construct a sample of point-masses along the full Galactic plane, which can be used to test models of the gravitational potential. In the CSEs of red giants, SiO maser emission is frequently observed at 43 and 86 GHz, providing line-of-sight velocities. The Bulge Asymmetries and Dynamical Evolution (BAaDE) project aims to explore the complex structure of the inner Galaxy and Galactic Bulge, by observing 43 GHz SiO at the Very Large Array and 86 GHz SiO at the Atacama Large Millimeter/submillimeter Array, with an expected final sample of about 20,000 line-of-sight velocities and positions. We observed the 43 GHz and 86 GHz transitions near-simultaneously in a subsample of the sources using the Australia Telescope Compact Array and found that on average the 43 GHz v=1 line is 1.3 times stronger than the 86 GHz v=1 line. The presence of a detectable 43 GHz v=3 line alters the statistics, consistent with the SiO masers displaying 43 GHz v=3 emission arising in a denser regime in the circumstellar shell compared to those without. Comparing our results with radiative models implies that the 43 GHz v=3 line is a tracer of density variations caused by stellar pulsations. We will discuss these results in the context of the BAaDE project.

  16. Shifting of the resonance location for planets embedded in circumstellar disks

    Science.gov (United States)

    Marzari, F.

    2018-03-01

    Context. In the early evolution of a planetary system, a pair of planets may be captured in a mean motion resonance while still embedded in their nesting circumstellar disk. Aims: The goal is to estimate the direction and amount of shift in the semimajor axis of the resonance location due to the disk gravity as a function of the gas density and mass of the planets. The stability of the resonance lock when the disk dissipates is also tested. Methods: The orbital evolution of a large number of systems is numerically integrated within a three-body problem in which the disk potential is computed as a series of expansion. This is a good approximation, at least over a limited amount of time. Results: Two different resonances are studied: the 2:1 and the 3:2. In both cases the shift is inwards, even if by a different amount, when the planets are massive and carve a gap in the disk. For super-Earths, the shift is instead outwards. Different disk densities, Σ, are considered and the resonance shift depends almost linearly on Σ. The gas dissipation leads to destabilization of a significant number of resonant systems, in particular if it is fast. Conclusions: The presence of a massive circumstellar disk may significantly affect the resonant behavior of a pair of planets by shifting the resonant location and by decreasing the size of the stability region. The disk dissipation may explain some systems found close to a resonance but not locked in it.

  17. Infrared spectrophotometry and radiative transfer in optically thick circumstellar dust envelopes

    International Nuclear Information System (INIS)

    Merrill, K.M.

    1976-01-01

    The Two-Micron Sky Survey of Neugebauer and Leighton and, more recently, the AFCRL Infrared Sky Survey of Walker and Price have detected numerous compact, isolated, bright infrared sources which are not identified with previously cataloged stars. Observations of many such objects suggest that extensive circumstellar dust envelopes modify the flux from a central source. The present investigations employ broad bandpass photometry at lambda lambda 1.65 μm to 12.5 μm and narrow bandpass spectrophotometry (Δ lambda/lambda approximately 0.015) at lambda lambda 2-4 μm and lambda lambda 8-13 μm to determine the properties of a large sample of such infrared sources. Infrared spectrophotometry can clearly differentiate between normal stars of spectral types M(''oxygen-rich'') and C (''carbon-rich'') on the basis of characteristic absorption bands arising in cool stellar atmospheres. Most of the 2 μ Sky Survey and many of the AFCRL Sky Survey sources appear to be stars of spectral types M and C which are differentiated from normal cool comparison stars only by the presence of extensive circumstellar dust envelopes. Due to the large optical depth of the envelopes, the flux from the star and from the dust cannot be simply separated. Hence solutions of radiative transfer through spherically symmetric envelopes of arbitrary optical depth were generated by a generalized computer code which employed opacities of real dust

  18. Mass loss from OH/IR stars - Models for the infrared emission of circumstellar dust shells

    Science.gov (United States)

    Justtanont, K.; Tielens, A. G. G. M.

    1992-01-01

    The IR emission of a sample of 24 OH/IR stars is modeled, and the properties of circumstellar dust and mass-loss rate of the central star are derived. It is shown that for some sources the observations of the far-IR emission is well fitted with a lambda exp -1 law, while some have a steeper index of 1.5. For a few sources, the presence of circumstellar ice grains is inferred from detailed studies of the observed 10-micron feature. Dust mass-loss rates are determined from detailed studies for all the stars in this sample. They range from 6.0 x 10 exp -10 solar mass/yr for an optically visible Mira to 2.2 x 10 exp -6 solar mass/yr for a heavily obscured OH/IR star. These dust mass-loss rates are compared to those calculated from IRAS photometry using 12-, 25-, and 60-micron fluxes. The dust mass-loss rates are also compared to gas mass-loss rates determined from OH and CO observations. For stars with tenuous shells, a dust-to-gas ratio of 0.001 is obtained.

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

    Science.gov (United States)

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

    2012-02-01

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

  20. ARCSECOND RESOLUTION MAPPING OF SULFUR DIOXIDE EMISSION IN THE CIRCUMSTELLAR ENVELOPE OF VY CANIS MAJORIS

    International Nuclear Information System (INIS)

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

    2012-01-01

    We report Submillimeter Array observations of SO 2 emission in the circumstellar envelope (CSE) of the red supergiant VY Canis Majoris, with an angular resolution of ≈1''. SO 2 emission appears in three distinct outflow regions surrounding the central continuum peak emission that is spatially unresolved. No bipolar structure is noted in the sources. A fourth source of SO 2 is identified as a spherical wind centered at the systemic velocity. We estimate the SO 2 column density and rotational temperature assuming local thermal equilibrium (LTE) as well as perform non-LTE radiative transfer analysis using RADEX. Column densities of SO 2 are found to be ∼10 16 cm –2 in the outflows and in the spherical wind. Comparison with existing maps of the two parent species OH and SO shows the SO 2 distribution to be consistent with that of OH. The abundance ratio f SO 2 /f SO is greater than unity for all radii larger than 3 × 10 16 cm. SO 2 is distributed in fragmented clumps compared to SO, PN, and SiS molecules. These observations lend support to specific models of circumstellar chemistry that predict f SO 2 /f SO >1 and may suggest the role of localized effects such as shocks in the production of SO 2 in the CSE.

  1. The peculiar balmer decrement of SN 2009ip: Constraints on circumstellar geometry

    Energy Technology Data Exchange (ETDEWEB)

    Levesque, Emily M.; Stringfellow, Guy S.; Bally, John; Keeney, Brian A. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado 389-UCB, Boulder, CO 80309 (United States); Ginsburg, Adam G., E-mail: Emily.Levesque@colorado.edu [European Southern Observatory, ESO Headquarters, Karl-Schwarzschild-Strasse 2, D-95748 Garching bei München (Germany)

    2014-01-01

    We present optical and near-IR spectroscopic observations of the luminous blue variable SN 2009ip during its remarkable photometric evolution of 2012. The spectra sample three key points in the SN 2009ip light curve, corresponding to its initial brightening in August (2012-A) and its dramatic rebrightening in early October (2012-B). Based on line fluxes and velocities measured in our spectra, we find a surprisingly low I(Hα)/I(Hβ) ratio (∼1.3-1.4) in the 2012-B spectra. Such a ratio implies either a rare Case B recombination scenario where Hα, but not Hβ, is optically thick, or an extremely high density for the circumstellar material of n{sub e} > 10{sup 13} cm{sup –3}. The Hα line intensity yields a minimum radiating surface area of ≳20,000 AU{sup 2} in Hα at the peak of SN 2009ip's photometric evolution. Combined with the nature of this object's spectral evolution in 2012, a high circumstellar density and large radiating surface area imply the presence of a thin disk geometry around the central star (and, consequently, a possible binary companion), suggesting that the observed 2012-B rebrightening of SN 2009ip can be attributed to the illumination of the disk's inner rim by fast-moving ejecta produced by the underlying events of 2012-A.

  2. THE PDS 66 CIRCUMSTELLAR DISK AS SEEN IN POLARIZED LIGHT WITH THE GEMINI PLANET IMAGER

    International Nuclear Information System (INIS)

    Wolff, Schuyler G.; Greenbaum, Alexandra Z.; Perrin, Marshall; Hines, Dean C.; Millar-Blanchaer, Maxwell A.; Nielsen, Eric L.; Wang, Jason; Dong, Ruobing; Duchêne, Gaspard; Graham, James R.; Kalas, Paul; Cardwell, Andrew; Chilcote, Jeffrey; Draper, Zachary H.; Fitzgerald, Michael P.; Hung, Li-Wei; Goodsell, Stephen J.; Grady, Carol A.; Hartung, Markus; Hibon, Pascale

    2016-01-01

    We present H- and K-band imaging polarimetry for the PDS 66 circumstellar disk obtained during the commissioning of the Gemini Planet Imager (GPI). Polarization images reveal a clear detection of the disk in to the 0.″12 inner working angle (IWA) in the H band, almost three times closer to the star than the previous Hubble Space Telescope (HST) observations with NICMOS and STIS (0.″35 effective IWA). The centro-symmetric polarization vectors confirm that the bright inner disk detection is due to circumstellar scattered light. A more diffuse disk extends to a bright outer ring centered at 80 AU. We discuss several physical mechanisms capable of producing the observed ring + gap structure. GPI data confirm enhanced scattering on the east side of the disk that is inferred to be nearer to us. We also detect a lateral asymmetry in the south possibly due to shadowing from material within the IWA. This likely corresponds to a temporally variable azimuthal asymmetry observed in HST/STIS coronagraphic imaging

  3. THE PDS 66 CIRCUMSTELLAR DISK AS SEEN IN POLARIZED LIGHT WITH THE GEMINI PLANET IMAGER

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, Schuyler G.; Greenbaum, Alexandra Z. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Perrin, Marshall; Hines, Dean C. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Millar-Blanchaer, Maxwell A. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Nielsen, Eric L. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Wang, Jason; Dong, Ruobing; Duchêne, Gaspard; Graham, James R.; Kalas, Paul [Astronomy Department, University of California, Berkeley, Berkeley, CA 94720 (United States); Cardwell, Andrew [LBT Observatory, University of Arizona, 933 N. Cherry Avenue, Room 552, Tucson, AZ 85721 (United States); Chilcote, Jeffrey [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Draper, Zachary H. [University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2 (Canada); Fitzgerald, Michael P.; Hung, Li-Wei [Department of Physics and Astronomy, University of California, Los Angeles, 430 Portola Plaza, Los Angeles, CA 90095 (United States); Goodsell, Stephen J. [Gemini Observatory, 670 N. A’ohoku Place, Hilo, HI 96720 (United States); Grady, Carol A. [Eureka Scientific, 2452 Delmer, Suite 100, Oakland, CA 96002 (United States); Hartung, Markus; Hibon, Pascale, E-mail: swolff9@jh.edu [Gemini Observatory, Casilla 603, La Serena (Chile); and others

    2016-02-10

    We present H- and K-band imaging polarimetry for the PDS 66 circumstellar disk obtained during the commissioning of the Gemini Planet Imager (GPI). Polarization images reveal a clear detection of the disk in to the 0.″12 inner working angle (IWA) in the H band, almost three times closer to the star than the previous Hubble Space Telescope (HST) observations with NICMOS and STIS (0.″35 effective IWA). The centro-symmetric polarization vectors confirm that the bright inner disk detection is due to circumstellar scattered light. A more diffuse disk extends to a bright outer ring centered at 80 AU. We discuss several physical mechanisms capable of producing the observed ring + gap structure. GPI data confirm enhanced scattering on the east side of the disk that is inferred to be nearer to us. We also detect a lateral asymmetry in the south possibly due to shadowing from material within the IWA. This likely corresponds to a temporally variable azimuthal asymmetry observed in HST/STIS coronagraphic imaging.

  4. IDENTIFYING NEARBY, YOUNG, LATE-TYPE STARS BY MEANS OF THEIR CIRCUMSTELLAR DISKS

    International Nuclear Information System (INIS)

    Schneider, Adam; Song, Inseok; Melis, Carl; Zuckerman, B.; Bessell, Mike

    2012-01-01

    It has recently been shown that a significant fraction of late-type members of nearby, very young associations (age ∼<10 Myr) display excess emission at mid-IR wavelengths indicative of dusty circumstellar disks. We demonstrate that the detection of mid-IR excess emission can be utilized to identify new nearby, young, late-type stars including two definite new members ('TWA 33' and 'TWA 34') of the TW Hydrae Association (TWA). Both new TWA members display mid-IR excess emission in the Wide-field Infrared Survey Explorer catalog and they show proper motion and youthful spectroscopic characteristics—namely, Hα emission, strong lithium absorption, and low surface gravity features consistent with known TWA members. We also detect mid-IR excess—the first unambiguous evidence of a dusty circumstellar disk—around a previously identified UV-bright, young, accreting star (2M1337) that is a likely member of the Lower-Centaurus Crux region of the Scorpius-Centaurus Complex.

  5. Sci—Fri PM: Topics — 05: Experience with linac simulation software in a teaching environment

    International Nuclear Information System (INIS)

    Carlone, Marco; Harnett, Nicole; Jaffray, David; Norrlinger, Bern; Prooijen, Monique van; Milne, Emily

    2014-01-01

    Medical linear accelerator education is usually restricted to use of academic textbooks and supervised access to accelerators. To facilitate the learning process, simulation software was developed to reproduce the effect of medical linear accelerator beam adjustments on resulting clinical photon beams. The purpose of this report is to briefly describe the method of operation of the software as well as the initial experience with it in a teaching environment. To first and higher orders, all components of medical linear accelerators can be described by analytical solutions. When appropriate calibrations are applied, these analytical solutions can accurately simulate the performance of all linear accelerator sub-components. Grouped together, an overall medical linear accelerator model can be constructed. Fifteen expressions in total were coded using MATLAB v 7.14. The program was called SIMAC. The SIMAC program was used in an accelerator technology course offered at our institution; 14 delegates attended the course. The professional breakdown of the participants was: 5 physics residents, 3 accelerator technologists, 4 regulators and 1 physics associate. The course consisted of didactic lectures supported by labs using SIMAC. At the conclusion of the course, eight of thirteen delegates were able to successfully perform advanced beam adjustments after two days of theory and use of the linac simulator program. We suggest that this demonstrates good proficiency in understanding of the accelerator physics, which we hope will translate to a better ability to understand real world beam adjustments on a functioning medical linear accelerator

  6. Star Formation in High Pressure, High Energy Density Environments: Laboratory Experiments of ISM Dust Analogs

    International Nuclear Information System (INIS)

    Breugel, W. van; Bajt, S.; Bradley, J.; Bringa, E.; Dai, Z.; Felter, T.; Graham, G.; Kucheyev, S.; Torres, D.; Tielens, A.; Baragiola, R.; Dukes, C.; Loeffler, M.

    2005-01-01

    Dust grains control the chemistry and cooling, and thus the gravitational collapse of interstellar clouds. Energetic particles, shocks and ionizing radiation can have a profound influence on the structure, lifetime and chemical reactivity of the dust, and therefore on the star formation efficiency. This would be especially important in forming galaxies, which exhibit powerful starburst (supernovae) and AGN (active galactic nucleus) activity. How dust properties are affected in such environments may be crucial for a proper understanding of galaxy formation and evolution. The authors present the results of experiments at LLNL which show that irradiation of the interstellar medium (ISM) dust analog forsterite (Mg 2 SiO 4 ) with swift heavy ions (10 MeV Xe) and a large electronic energy deposition amorphizes its crystalline structure, without changing its chemical composition. From the data they predict that silicate grains in the ISM, even in dense and cold giant molecular clouds, can be amorphized by heavy cosmic rays (CR's). This might provide an explanation for the observed absence of crystalline dust in the ISM clouds of the Milky Way galaxy. This processing of dust by CR's would be even more important in forming galaxies and galaxies with active black holes

  7. THE ROLE OF TEENAGEERS’ LIFE EXPERIENCE ACTUALIZATION IN THE FRAMEWORK OF THE SAFE SOCIAL ENVIRONMENT FORMATION

    Directory of Open Access Journals (Sweden)

    O. A. Selivanov

    2013-01-01

    Full Text Available The paper looks at the problem of social security and emphasizes the urgent need for developing the general theory of social security, its concepts and models designed to meet the requirements of time and specify different aspects and levels of socialization process – federal, regional and municipal. The author regards actualization of teenagers’ life experience as a promising direction for exploring the opportunities for creating the safe social environment.The individual socio-psychological functioning is delineated as a multilevel correlation of internal and external human resources used for resolving difficult situations. According to the author, the prompt mobilization of internal resources of a teenager, training the ability to apply the external resources for solving the problem and developing the safe behavior can improve the quality of life in the modern society. Along with the risks of modern information society, the author emphasizes a number of dangerous social trends: disruption of social institutions, ifantilization of education, distortion of historical cultural channels, and devaluation of the collectivism idea.In author’s opinion, teenagers should get some special knowledge and individual training to develop the skills of safe behavior in actual situations; and the prospects of the modern society considerably depend on the above procedures. 

  8. Sci—Fri PM: Topics — 05: Experience with linac simulation software in a teaching environment

    Energy Technology Data Exchange (ETDEWEB)

    Carlone, Marco; Harnett, Nicole; Jaffray, David [Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Norrlinger, Bern; Prooijen, Monique van; Milne, Emily [Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON (Canada)

    2014-08-15

    Medical linear accelerator education is usually restricted to use of academic textbooks and supervised access to accelerators. To facilitate the learning process, simulation software was developed to reproduce the effect of medical linear accelerator beam adjustments on resulting clinical photon beams. The purpose of this report is to briefly describe the method of operation of the software as well as the initial experience with it in a teaching environment. To first and higher orders, all components of medical linear accelerators can be described by analytical solutions. When appropriate calibrations are applied, these analytical solutions can accurately simulate the performance of all linear accelerator sub-components. Grouped together, an overall medical linear accelerator model can be constructed. Fifteen expressions in total were coded using MATLAB v 7.14. The program was called SIMAC. The SIMAC program was used in an accelerator technology course offered at our institution; 14 delegates attended the course. The professional breakdown of the participants was: 5 physics residents, 3 accelerator technologists, 4 regulators and 1 physics associate. The course consisted of didactic lectures supported by labs using SIMAC. At the conclusion of the course, eight of thirteen delegates were able to successfully perform advanced beam adjustments after two days of theory and use of the linac simulator program. We suggest that this demonstrates good proficiency in understanding of the accelerator physics, which we hope will translate to a better ability to understand real world beam adjustments on a functioning medical linear accelerator.

  9. Cognitive endophenotypes, gene-environment interactions and experience-dependent plasticity in animal models of schizophrenia.

    Science.gov (United States)

    Burrows, Emma L; Hannan, Anthony J

    2016-04-01

    Schizophrenia is a devastating brain disorder caused by a complex and heterogeneous combination of genetic and environmental factors. In order to develop effective new strategies to prevent and treat schizophrenia, valid animal models are required which accurately model the disorder, and ideally provide construct, face and predictive validity. The cognitive deficits in schizophrenia represent some of the most debilitating symptoms and are also currently the most poorly treated. Therefore it is crucial that animal models are able to capture the cognitive dysfunction that characterizes schizophrenia, as well as the negative and psychotic symptoms. The genomes of mice have, prior to the recent gene-editing revolution, proven the most easily manipulable of mammalian laboratory species, and hence most genetic targeting has been performed using mouse models. Importantly, when key environmental factors of relevance to schizophrenia are experimentally manipulated, dramatic changes in the phenotypes of these animal models are often observed. We will review recent studies in rodent models which provide insight into gene-environment interactions in schizophrenia. We will focus specifically on environmental factors which modulate levels of experience-dependent plasticity, including environmental enrichment, cognitive stimulation, physical activity and stress. The insights provided by this research will not only help refine the establishment of optimally valid animal models which facilitate development of novel therapeutics, but will also provide insight into the pathogenesis of schizophrenia, thus identifying molecular and cellular targets for future preclinical and clinical investigations. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Data link air traffic control and flight deck environments: Experiment in flight crew performance

    Science.gov (United States)

    Lozito, Sandy; Mcgann, Alison; Corker, Kevin

    1993-01-01

    This report describes an experiment undertaken in a full mission simulation environment to investigate the performance impact of, and human/system response to, data-linked Air Traffic Control (ATC) and automated flight deck operations. Subjects were twenty pilots (ten crews) from a major United States air carrier. Crews flew the Advanced Concepts Flight Simulator (ACFS), a generic 'glass cockpit' simulator at NASA Ames. The method of data link used was similar to the data link implementation plans for a next-generation aircraft, and included the capability to review ATC messages and directly enter ATC clearance information into the aircraft systems. Each crew flew experimental scenarios, in which data reflecting communication timing, errors and clarifications, and procedures were collected. Results for errors and clarifications revealed an interaction between communication modality (voice v. data link) and communication type (air/ground v. intracrew). Results also revealed that voice crews initiated ATC contact significantly more than data link crews. It was also found that data link crews performed significantly more extraneous activities during the communication task than voice crews. Descriptive data from the use of the review menu indicate the pilot-not-flying accessing the review menu most often, and also suggest diffulty in accessing the target message within the review menu structure. The overall impact of communication modality upon air/ground communication and crew procedures is discussed.

  11. Development of an Acoustic Localization Method for Cavitation Experiments in Reverberant Environments

    Science.gov (United States)

    Ranjeva, Minna; Thompson, Lee; Perlitz, Daniel; Bonness, William; Capone, Dean; Elbing, Brian

    2011-11-01

    Cavitation is a major concern for the US Navy since it can cause ship damage and produce unwanted noise. The ability to precisely locate cavitation onset in laboratory scale experiments is essential for proper design that will minimize this undesired phenomenon. Measuring the cavitation onset is more accurately determined acoustically than visually. However, if other parts of the model begin to cavitate prior to the component of interest the acoustic data is contaminated with spurious noise. Consequently, cavitation onset is widely determined by optically locating the event of interest. The current research effort aims at developing an acoustic localization scheme for reverberant environments such as water tunnels. Currently cavitation bubbles are being induced in a static water tank with a laser, allowing the localization techniques to be refined with the bubble at a known location. The source is located with the use of acoustic data collected with hydrophones and analyzed using signal processing techniques. To verify the accuracy of the acoustic scheme, the events are simultaneously monitored visually with the use of a high speed camera. Once refined testing will be conducted in a water tunnel. This research was sponsored by the Naval Engineering Education Center (NEEC).

  12. The influence of learning environment on trainee pharmacy technicians' education and training experiences.

    Science.gov (United States)

    Schafheutle, Ellen I; Jee, Samuel D; Willis, Sarah C

    2017-12-16

    In Great Britain (GB), pharmacy technicians (PTs) are registered professionals, with their education and training regulated; little is known about this or the learning environment in which it takes place. This study aimed to profile recently registered pre-registration trainee pharmacy technicians (PTPTs) in GB and capture views on PTPTs' training experiences, focussing on differences in community and hospital settings. A mixed methods study was conducted in 2013-14, following university ethics approval. One-to-one, semi-structured telephone interviews with face-to-face and distance education providers, and hospital and community pharmacy employers of PTPTs explored views on education delivery, work-based learning, and assessment. Interviews were transcribed verbatim, analysed thematically and findings informed design of a census survey of all 1457 recently registered PTs, investigating satisfaction with various aspects of their training. Quantitative data were analysed using SPSS v20, employing comparative statistics (Mann-Whitney U, Chi-Square). Six-hundred and forty-six questionnaires were returned (response rate 44.3%), 632 were usable. Three-quarters (75.9%) of respondents had trained in community; the majority (88.0%) were female, the average age was 35.26 ± 10.22. Those based in hospitals were more satisfied with their training: hospital trainees worked in larger teams and tended to be better supported, they had more study time, and were more likely to complete their training in the intended two-year period. Interviews with staff in 17 Further Education colleges, 6 distance providers, 16 community pharmacies and 15 NHS organisations confirmed survey findings and offered explanations into why differences in training experiences may exist. This study has identified differences between PTPTs' work-based experiences in hospital and community pharmacy. Perceiving PTPTs as 'apprentices' vs. 'employees' may define how their training is managed by employers

  13. How scientific experiments are designed: Problem solving in a knowledge-rich, error-rich environment

    Science.gov (United States)

    Baker, Lisa M.

    While theory formation and the relation between theory and data has been investigated in many studies of scientific reasoning, researchers have focused less attention on reasoning about experimental design, even though the experimental design process makes up a large part of real-world scientists' reasoning. The goal of this thesis was to provide a cognitive account of the scientific experimental design process by analyzing experimental design as problem-solving behavior (Newell & Simon, 1972). Three specific issues were addressed: the effect of potential error on experimental design strategies, the role of prior knowledge in experimental design, and the effect of characteristics of the space of alternate hypotheses on alternate hypothesis testing. A two-pronged in vivo/in vitro research methodology was employed, in which transcripts of real-world scientific laboratory meetings were analyzed as well as undergraduate science and non-science majors' design of biology experiments in the psychology laboratory. It was found that scientists use a specific strategy to deal with the possibility of error in experimental findings: they include "known" control conditions in their experimental designs both to determine whether error is occurring and to identify sources of error. The known controls strategy had not been reported in earlier studies with science-like tasks, in which participants' responses to error had consisted of replicating experiments and discounting results. With respect to prior knowledge: scientists and undergraduate students drew on several types of knowledge when designing experiments, including theoretical knowledge, domain-specific knowledge of experimental techniques, and domain-general knowledge of experimental design strategies. Finally, undergraduate science students generated and tested alternates to their favored hypotheses when the space of alternate hypotheses was constrained and searchable. This result may help explain findings of confirmation

  14. Environment sensitization through arts: an experience with communities along Amazon rivers

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Wanderleia Isabel P. de; Gusmao, Dulce Milena Almeida [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2009-07-01

    In Brazil, the deforestation, pollution, losses in historic and cultural patrimony are each time more common in communities which, due to the great distances from urban centers, lack of any level of information. Normally, in these communities, theaters do not exist, nor local cinemas or places where people can have access to any type of art and culture. In this context, the Amazon suffers from the same problems than other regions in Brazil, however allied to logistic difficulties and other local specificities. That way, this work is about an experience lived in the Urucu-Coari-Manaus gas pipeline construction and assembly process, in which 18 communities were involved in a work of Environmental Education through arts: music, theater, movies, and others. In those communities there is great disinformation or distortion regarding programs and environmental plans from Urucu-Coari-Manaus gas pipeline, mainly due to the distance from urban centers and lack of communication vehicles. But this initiative did not come from an obligation or legal recommendations, but from a necessity to reach this public using an assertive communication. This work's specific goals were: To use the interpenetration between art and education and the playful, creative and humorous language of specific artistic interventions, adjusted to that public and its peculiarities, in order to lead the dialogue between different knowledge, that is, between traditional culture and environmental concepts paved in studies and scientific data, and to spread Urucu-Manaus gas pipeline environmental programs; To arise, in the artistic interventions, that specific public's participation and integration, always focusing the environmental message and the respect for the Amazonian culture; To value, in all artistic interventions, people's traditional knowledge, the Amazonian environment and, mainly, the importance of each local inhabitant for that environment's conservation, important for us all

  15. Examining the Relationship between the Research Training Environment, Course Experiences, and Graduate Students’ Research Self-Efficacy Beliefs

    Directory of Open Access Journals (Sweden)

    Steven Chesnut

    2015-10-01

    Full Text Available This study examined the relationship between graduate students’ research training environment, course experience, and research self-efficacy beliefs. The findings of the descriptive and regression analyses suggest that graduate students’ (n = 161 general research, quantitative, and qualitative research self-efficacy beliefs varied and that these beliefs were related to different aspects of the research training environment and course experiences, including their own personal research experiences. While course experience variables were significant predictors of quantitative and qualitative research self-efficacy, they were not predictive of general research methods self-efficacy. Also, while mentorship was a significant predictor of general research methods self-efficacy, it was not a significant predictor of quantitative and qualitative research self-efficacy. The implications of this study for research and graduate education are discussed.

  16. Designing Recreational Virtual Environments for Older Adult Nursing Home Residents - How Nature And Content Matter For Improving Augmented Exercise Experiences

    DEFF Research Database (Denmark)

    Bruun-Pedersen, Jon Ram; Serafin, Stefania; Maculewicz, Justyna

    2016-01-01

    In this paper, we discuss the design for restorative virtual environments (RVEs), specifically developed to augment rehabilitation exercise for older adult users living at nursing homes, in order to increase exercise motivation. User evaluations on these RVE designs suggest that the soundscapes did...... not have a noticeable role for user experience. Moreover, soundscapes might simply be perceived congruent with the visuals, and thus seamlessly accepted by users as an inherent part of the augmented exercise experience....

  17. Touch in Computer-Mediated Environments: An Analysis of Online Shoppers’ Touch-Interface User Experiences

    OpenAIRE

    Chung, Sorim

    2016-01-01

    Over the past few years, one of the most fundamental changes in current computer-mediated environments has been input devices, moving from mouse devices to touch interfaces. However, most studies of online retailing have not considered device environments as retail cues that could influence users’ shopping behavior. In this research, I examine the underlying mechanisms between input device environments and shoppers’ decision-making processes. In particular, I investigate the impact of input d...

  18. Culturally and linguistically diverse healthcare students' experiences of learning in a clinical environment: A systematic review of qualitative studies.

    Science.gov (United States)

    Mikkonen, Kristina; Elo, Satu; Kuivila, Heli-Maria; Tuomikoski, Anna-Maria; Kääriäinen, Maria

    2016-02-01

    Learning in the clinical environment of healthcare students plays a significant part in higher education. The greatest challenges for culturally and linguistically diverse healthcare students were found in clinical placements, where differences in language and culture have been shown to cause learning obstacles for students. There has been no systematic review conducted to examine culturally and linguistically diverse healthcare students' experiences of their learning in the clinical environment. This systematic review aims to identify culturally and linguistically diverse healthcare students' experiences of learning in a clinical environment. The search strategy followed the guidelines of the Centre of Reviews and Dissemination. The original studies were identified from seven databases (CINAHL, Medline Ovid, Scopus, Web of Science, Academic Search Premiere, Eric and Cochrane Library) for the period 2000-2014. Two researchers selected studies based on titles, abstracts and full texts using inclusion criteria and assessed the quality of studies independently. Twelve original studies were chosen for the review. The culturally and linguistically diverse healthcare students' learning experiences were divided into three influential aspects of learning in a clinical environment: experiences with implementation processes and provision; experiences with peers and mentors; and experiences with university support and instructions. The main findings indicate that culturally and linguistically diverse healthcare students embarking on clinical placements initially find integration stressful. Implementing the process of learning in a clinical environment requires additional time, well prepared pedagogical orientation, prior cultural and language education, and support for students and clinical staff. Barriers to learning by culturally and linguistically diverse healthcare students were not being recognized and individuals were not considered motivated; learners experienced the

  19. Taking Science Online: Evaluating Presence and Immersion through a Laboratory Experience in a Virtual Learning Environment for Entomology Students

    Science.gov (United States)

    Annetta, Leonard; Klesath, Marta; Meyer, John

    2009-01-01

    A 3-D virtual field trip was integrated into an online college entomology course and developed as a trial for the possible incorporation of future virtual environments to supplement online higher education laboratories. This article provides an explanation of the rationale behind creating the virtual experience, the Bug Farm; the method and…

  20. A laboratory experiment on the behaviour of soil-derived core and intact polar GDGTs in aquatic environments

    NARCIS (Netherlands)

    Peterse, F.; Moy, C. M.; Eglinton, T. I.

    2015-01-01

    We have performed incubation experiments in order to examine the behaviour of soil-derived branched glycerol dialkyl glycerol tetraether (brGDGT) membrane lipids upon entering an aquatic environment and to evaluate the processes that potentially take place during their fluvial transport from land to

  1. A comparative study on the flow experience in web-based and text-based interaction environments.

    Science.gov (United States)

    Huang, Li-Ting; Chiu, Chen-An; Sung, Kai; Farn, Cheng-Kiang

    2011-01-01

    The purpose of this study was to explore a substantial phenomenon related to flow experiences (immersion) in text-based interaction systems. Most previous research emphasizes the effects of challenge/skill, focused attention, telepresence, web characteristics, and systems' interface design on users' flow experiences in online environments. However, text-based interaction systems without telepresence features and web characteristics still seem to create opportunities for flow experience. To explore this phenomenon, this study incorporates subject involvement and interpersonal interaction as critical antecedents into the model of flow experience, as well as considers the existence of telepresence. Results reveal that subject involvement, interpersonal interaction, and interactivity speed are critical to focused attention, which enhances users' immersion. With regard to the effect of telepresence, the perceived attractiveness of the interface is a significant facilitator determining users' immersion in web-based, rather than in text-based, interaction environments. Interactivity speed is unrelated to immersion in both web-based and text-based interaction environments. The influence of interpersonal involvement is diminished in web-based interaction environments. The implications and limitations of this study are discussed.

  2. ISS-studio: a prototype for a user-friendly tool for designing interactive experiments in problem solving environments

    NARCIS (Netherlands)

    Zhao, Z.; van Albada, G.D.; Tirado-Ramos, A.; Zajac, K.; Sloot, P.M.A.

    2003-01-01

    In Problem Solving Environments (PSE), Interactive Simulation Systems (ISS) are an important interactive mode for studying complex scientific problems. But efficient and user-friendly tools for designing interactive experiments lack in many PSEs. Mechanisms, such as data flow and control flow

  3. Profile control simulations and experiments on TCV : A controller test environment and results using a model-based predictive controller

    NARCIS (Netherlands)

    Maljaars, E.; Felici, F.; Blanken, T.C.; Galperti, C.; Sauter, O.; de Baar, M.R.; Carpanese, F.; Goodman, T.P.; Kim, D.; Kim, S.H.; Kong, M.G.; Mavkov, B.; Merle, A.; Moret, J.M.; Nouailletas, R.; Scheffer, M.; Teplukhina, A.A.; Vu, N.M.T.

    2017-01-01

    The successful performance of a model predictive profile controller is demonstrated in simulations and experiments on the TCV tokamak, employing a profile controller test environment. Stable high-performance tokamak operation in hybrid and advanced plasma scenarios requires control over the safety

  4. Profile control simulations and experiments on TCV: a controller test environment and results using a model-based predictive controller

    NARCIS (Netherlands)

    Maljaars, B.; Felici, F.; Blanken, T. C.; Galperti, C.; Sauter, O.; de Baar, M. R.; Carpanese, F.; Goodman, T. P.; Kim, D.; Kim, S. H.; Kong, M.; Mavkov, B.; Merle, A.; Moret, J.; Nouailletas, R.; Scheffer, M.; Teplukhina, A.; Vu, T.

    2017-01-01

    The successful performance of a model predictive profile controller is demonstrated in simulations and experiments on the TCV tokamak, employing a profile controller test environment. Stable high-performance tokamak operation in hybrid and advanced plasma scenarios requires control over the safety

  5. Experiencing the "Wild Woods": The Impact of Pedagogy on Children's Experience of a Natural Environment

    Science.gov (United States)

    Mawson, William Brent

    2014-01-01

    Outdoor play environments offer a wide range of potential affordances to both teachers and children. Teachers' pedagogy is a strong determining factor in children's ability to utilise the affordances of a particular environment. This article describes the way in which a group of teachers and children in a New Zealand education and care centre…

  6. Touch in Computer-Mediated Environments: An Analysis of Online Shoppers' Touch-Interface User Experiences

    Science.gov (United States)

    Chung, Sorim

    2016-01-01

    Over the past few years, one of the most fundamental changes in current computer-mediated environments has been input devices, moving from mouse devices to touch interfaces. However, most studies of online retailing have not considered device environments as retail cues that could influence users' shopping behavior. In this research, I examine the…

  7. The Virtual GloveboX (VGX: a Semi-immersive Virtual Environment for Training Astronauts in Life Sciences Experiments

    Directory of Open Access Journals (Sweden)

    I. Alexander Twombly

    2004-06-01

    Full Text Available The International Space Station will soon provide an unparalleled research facility for studying the near- and longer-term effects of microgravity on living systems. Using the Space Station Glovebox Facility - a compact, fully contained reach-in environment - astronauts will conduct technically challenging life sciences experiments. Virtual environment technologies are being developed at NASA Ames Research Center to help realize the scientific potential of this unique resource by facilitating the experimental hardware and protocol designs and by assisting the astronauts in training. The "Virtual GloveboX" (VGX integrates high-fidelity graphics, force-feedback devices and real-time computer simulation engines to achieve an immersive training environment. Here, we describe the prototype VGX system, the distributed processing architecture used in the simulation environment, and modifications to the visualization pipeline required to accommodate the display configuration.

  8. Women's perceived work environment after stress-related rehabilitation: experiences from the ReDO project.

    Science.gov (United States)

    Wästberg, Birgitta A; Erlandsson, Lena-Karin; Eklund, Mona

    2016-01-01

    The study aimed to investigate (a) if women's perceptions of their work environment changed during a 16-week rehabilitation period and at a 12-month follow-up; (b) whether such changes were related to outcomes in terms of return to work, well-being and valued occupations. Eighty-four gainfully employed women on sick-leave due to stress-related disorders responded to instruments assessing perceptions of the work environment, well-being (self-esteem, self-mastery, quality of life, perceived stress, self-rated health) and perceived occupational value. Data about return to work were collected from registers. Non-parametric statistics were used. The increase in the women's ratings of their work environment was non-significant between baseline and completed rehabilitation but was statistically significant between baseline and the 12-month follow-up. No relationships were found between changes in perceptions of the work environment and outcomes after the rehabilitation. At the follow-up, however, there were associations between perceived work environment changes in a positive direction and return to work; improved self-esteem, self-mastery, quality of life, perceived occupational value and self-rated health; and reduced stress. It seems important to consider the work environment in rehabilitation for stress-related problems, and a follow-up appears warranted to detect changes and associations not visible immediately after rehabilitation. Work environment Perceptions of the work environment seem important for return to work, although other factors are likely to contribute as well. Perceptions of the work environment are associated with several aspects of well-being. When developing rehabilitation interventions a focus on the clients' perceptions of their work environment seems vital.

  9. INTERPRETATION OF INFRARED VIBRATION-ROTATION SPECTRA OF INTERSTELLAR AND CIRCUMSTELLAR MOLECULES

    International Nuclear Information System (INIS)

    Lacy, John H.

    2013-01-01

    Infrared vibration-rotation lines can be valuable probes of interstellar and circumstellar molecules, especially symmetric molecules, which have no pure rotational transitions. But most such observations have been interpreted with an isothermal absorbing slab model, which leaves out important radiative transfer and molecular excitation effects. A more realistic non-LTE and non-isothermal radiative transfer model has been constructed. The results of this model are in much better agreement with the observations, including cases where lines in one branch of a vibration-rotation band are in absorption and another in emission. In general, conclusions based on the isothermal absorbing slab model can be very misleading, but the assumption of LTE may not lead to such large errors, particularly if the radiation field temperature is close to the gas temperature.

  10. A Model of Silicate Grain Nucleation and Growth in Circumstellar Outflows

    Science.gov (United States)

    Paquette, John A.; Ferguson, Frank T.; Nuth, Joseph A., III

    2011-01-01

    Based on its abundance, high bond energy, and recent measurements of its vapor pressure SiO is a natural candidate for dust nucleation in circumstellar outflows around asymptotic giant branch stars. In this paper, we describe a model of the nucleation and growth of silicate dust in such outflows. The sensitivity of the model to varying choices of poorly constrained chemical parameters is explored, and the merits of using scaled rather than classical nucleation theory are briefly considered, An elaboration of the model that includes magnesium and iron as growth species is then presented and discussed. The composition of the bulk of the grains derived from the model is consistent with olivines and pyroxenes, but somewhat metal-rich grains and very small, nearly pure SiO grains are also produced,

  11. Heating the Primordial Soup: X-raying the Circumstellar Disk of RY Lupi

    Science.gov (United States)

    Principe, David

    2015-09-01

    X-ray irradiation of circumstellar disks plays a vital role in their chemical evolution yet few high resolution X-ray observations exist characterizing both the disk-illuminating radiation field and the soft energy spectrum absorbed by the disk. We propose HETG spectroscopic observations of RY Lupi, a rare example of a nearly edge-on, actively accreting star-disk system within 150 pc. We aim to take advantage of its unique viewing geometry with the goals of (a) determining the intrinsic X-ray spectrum of the central pre-MS star so as to establish whether its X-ray emission can be attributed to accretion shocks or coronal emission, and (b) model the spectrum of X-rays absorbed by its gaseous disk. These results will serve as essential input to models of irradiated, planet-forming disks.

  12. The circumstellar envelopes of F and G type supergiants in the large magellanic cloud

    International Nuclear Information System (INIS)

    Hagen, W.; Humphreys, R.M.; Stencel, R.E.

    1981-01-01

    We have obtained high-dispersion echellograms at 2.5 and 5.1 A/mm of four F and G-type supergiants (Msub(V) approximately -9) in the large Magellanic Cloud for the purpose of studying their outer atmospheres as compared to their Milky Way counterparts. Line doubling at Na I D indicates extensive circumstellar envelopes and mass loss rates in excess of 10 -5 M . yr -1 with outflow velocities of 10-60 km s -1 . Deep exposures at Ca II H and K reveal new information about the chromospheres of extragalactic stars. The presence of H and K wing emission lines augments this, and also provides an independent way of estimating Msub(V). (author)

  13. MOLECULAR LINE OBSERVATIONS OF THE CARBON-RICH CIRCUMSTELLAR ENVELOPE CIT 6 AT 7 mm WAVELENGTHS

    Energy Technology Data Exchange (ETDEWEB)

    Chau, Wayne; Zhang Yong; Nakashima, Jun-ichi; Kwok, Sun [Department of Physics, University of Hong Kong (Hong Kong); Deguchi, Shuji [Nobeyama Radio Observatory, National Astronomical Observatory, Minamimaki, Minamisaku, Nagano 384-1305 (Japan)

    2012-11-20

    We present a {lambda}7 mm spectral line survey of the carbon-rich circumstellar envelope (CSE) CIT 6 using the 45 m telescope at the Nobeyama Radio Observatory. A total of 25 spectral features belonging to five molecular species (HC{sub 3}N, HC{sub 5}N, HC{sub 7}N, SiO, and CS) are detected, enabling us to investigate the chemistry of cyanopolyyne chains. The line strengths are compared with those of the proto-typical carbon-rich CSE IRC+10216. The results show that the cyanopolyyne molecules are enhanced in CIT 6, suggesting that it is more evolved than IRC+10216. In order to investigate the structure of CIT 6, we have constructed a three-dimensional spatiokinematic model. By comparing the observed line profiles with the models, we conclude that this envelope is asymmetric and is composed of several incomplete shells.

  14. Circumstellar envelopes of Cepheids: a possible bias affecting the distance scale?

    Science.gov (United States)

    Kervella, Pierre; Gallenne, Alexandre; Mérand, Antoine

    2013-02-01

    Circumstellar envelopes (CSEs) have been detected around many Cepheids, first based on long-baseline interferometry, and now also using other observing techniques. These envelopes are particularly interesting for two reasons: their presence could impact the Cepheid distance scale, and they may be valuable tracers of stellar mass loss. Here we focus on their potential impact on the calibration of the Cepheid distance scale. We consider the photometric contribution of the envelopes in the visible, near-, and thermal-infrared domains. We conclude that the impact of CSEs on the apparent luminosities of Cepheids is negligible at visible wavelengths and generally weak (case. Overall, the contribution of CSEs to the usual period-luminosity relations (from the visible to the K band) is mostly negligible. They could affect calibrations at longer wavelengths, although the presence of envelopes may have been partially taken into account in the existing empirical calibrations.

  15. The character and behaviour of circumstellar shells at T Tauri stars

    International Nuclear Information System (INIS)

    Goetz, W.

    1988-01-01

    T Tauri stars are extremely young low-mass stars in the pre-main sequence stage. A brief review of investigations made at the Sonneberg observatory concerning the character and the behaviour of circumstellar shells at T Tauri stars is given. They lead to the construction of a shell model on the basis of observational facts. The idea rests upon the causal connection between the gas and dust shell phenomenon and the cosmogonic mass loss of the stars, which is the connecting link between the stars and their shells and which appears in the early phase of the pre-main sequence stage and decreases, like the accompanying shell phenomena, during the evolution of the stars. (author)

  16. A review of human thermal comfort experiments in controlled and semi-controlled environments

    NARCIS (Netherlands)

    Craenendonck, Van Stijn; Lauriks, Leen; Vuye, Cedric; Kampen, Jarl

    2018-01-01

    There are three main methods to improve thermal comfort in existing buildings: modeling, experiments and measurements. Regarding experiments, no standardized procedure exists. This article provides an answer to the question: “What is the most common practice for human thermal comfort experiments in

  17. Navigating a strange and complex environment: experiences of Sudanese refugee women using a new nutrition resource

    Directory of Open Access Journals (Sweden)

    Mannion CA

    2014-04-01

    Full Text Available Cynthia A Mannion, Shelley Raffin-Bouchal, Christena Jane HenshawFaculty of Nursing, University of Calgary, Calgary, Alberta, CanadaBackground: Refugees experience dietary changes as part of the daily challenges they face resettling in a new country. Sudanese women seek to care and feed their families, but face language barriers in the marketplace, limited access to familiar foods, and forced new food choices. This study aimed to understand the acceptability of a purse-sized nutrition resource, “The Market Guide”, which was developed to help recently immigrated Sudanese refugee women identify and purchase healthy foods and navigate grocery stores.Methods: Eight women participated in a focus group, four of whom were also observed during accompanied grocery store visits. Individual interviews were conducted with four health care workers at the resettlement center to gather perceptions about the suitability of The Market Guide. Focus groups and interviews were audiotaped and transcribed. Data from field notes and transcripts were analyzed using grounded theory for preliminary open codes, followed by selective and theoretical coding.Results: The Market Guide was of limited use to Sudanese women. Their response to this resource revealed the struggles of women acculturating during their first year in Calgary, Canada. We discovered the basic social process, “Navigating through a strange and complex environment: learning ways to feed your family.” Language, transportation, and an unfamiliar marketplace challenged women and prevented them from exercising their customary role of “knowing” which foods were “safe and good” for their families. The nutrition resource fell short of informing food choices and purchases, and we discovered that “learning to feed your family” is a relational process where trusted persons, family, and friends help navigate dietary acculturation.Conclusion: Emergent theory based on the basic social process may

  18. Characterizing the Evolution of Circumstellar Systems with the Hubble Space Telescope and the Gemini Planet Imager

    Science.gov (United States)

    Wolff, Schuyler; Schuyler G. Wolff

    2018-01-01

    The study of circumstellar disks at a variety of evolutionary stages is essential to understand the physical processes leading to planet formation. The recent development of high contrast instruments designed to directly image the structures surrounding nearby stars, such as the Gemini Planet Imager (GPI) and coronagraphic data from the Hubble Space Telescope (HST) have made detailed studies of circumstellar systems possible. In my thesis work I detail the observation and characterization of three systems. GPI polarization data for the transition disk, PDS 66 shows a double ring and gap structure with a temporally variable azimuthal asymmetry. This evolved morphology could indicate shadowing from some feature in the innermost regions of the disk, a gap-clearing planet, or a localized change in the dust properties of the disk. Millimeter continuum data of the DH Tau system places limits on the dust mass that is contributing to the strong accretion signature on the wide-separation planetary mass companion, DH Tau b. The lower than expected dust mass constrains the possible formation mechanism, with core accretion followed by dynamical scattering being the most likely. Finally, I present HST scattered light observations of the flared, edge-on protoplanetary disk ESO H$\\alpha$ 569. I combine these data with a spectral energy distribution to model the key structural parameters such as the geometry (disk outer radius, vertical scale height, radial flaring profile), total mass, and dust grain properties in the disk using the radiative transfer code MCFOST. In order to conduct this work, I developed a new tool set to optimize the fitting of disk parameters using the MCMC code \\texttt{emcee} to efficiently explore the high dimensional parameter space. This approach allows us to self-consistently and simultaneously fit a wide variety of observables in order to place constraints on the physical properties of a given disk, while also rigorously assessing the uncertainties in

  19. How nurses and their work environment affect patient experiences of the quality of care: a qualitative study

    Science.gov (United States)

    2014-01-01

    Background Healthcare organisations monitor patient experiences in order to evaluate and improve the quality of care. Because nurses spend a lot of time with patients, they have a major impact on patient experiences. To improve patient experiences of the quality of care, nurses need to know what factors within the nursing work environment are of influence. The main focus of this research was to comprehend the views of Dutch nurses on how their work and their work environment contribute to positive patient experiences. Methods A descriptive qualitative research design was used to collect data. Four focus groups were conducted, one each with 6 or 7 registered nurses in mental health care, hospital care, home care and nursing home care. A total of 26 nurses were recruited through purposeful sampling. The interviews were audiotaped, transcribed and subjected to thematic analysis. Results The nurses mentioned essential elements that they believe would improve patient experiences of the quality of nursing care: clinically competent nurses, collaborative working relationships, autonomous nursing practice, adequate staffing, control over nursing practice, managerial support and patient-centred culture. They also mentioned several inhibiting factors, such as cost-effectiveness policy and transparency goals for external accountability. Nurses feel pressured to increase productivity and report a high administrative workload. They stated that these factors will not improve patient experiences of the quality of nursing care. Conclusions According to participants, a diverse range of elements affect patient experiences of the quality of nursing care. They believe that incorporating these elements into daily nursing practice would result in more positive patient experiences. However, nurses work in a healthcare context in which they have to reconcile cost-efficiency and accountability with their desire to provide nursing care that is based on patient needs and preferences, and

  20. Skylab experiments. Volume 3: Materials science. [Skylab experiments on metallurgy, crystal growth, semiconductors, and combustion physics in weightless environment for high school level education

    Science.gov (United States)

    1973-01-01

    The materials science and technology investigation conducted on the Skylab vehicle are discussed. The thirteen experiments that support these investigations have been planned to evaluate the effect of a weightless environment on melting and resolidification of a variety of metals and semiconductor crystals, and on combustion of solid flammable materials. A glossary of terms which define the space activities and a bibliography of related data are presented.

  1. The South African Military Nursing College Pupil Enrolled Nurses’ experiences of the clinical learning environment

    Directory of Open Access Journals (Sweden)

    Ernestina M. Caka

    2013-06-01

    Full Text Available The study focused on the clinical learning experiences of Pupil Enrolled Nurses (PENs within the military health service. The purpose of the research was to explore and describe the learning experiences of PENs within the Military health clinical learning environment. An explorative, descriptive, contextual design which is qualitative in nature was used to guide the study. The military as a training institution prides itself on preparing nurses both as soldiers and nurses, this could be both challenging and exasperating for students, as the scopes are diverse. Being notably very hierarchical, the military’s rules constantly take precedence over nursing rules. For the duration of nursing training, students are allocated in the clinical learning area to acquire competencies such as problem solving, cognitive and psychomotor skills (Kuiper & Pesut 2003:383. Students learn how to merge theory and practice and apply theories in the practical sense. This is however, not done in isolation from the military codes, as they are intertwined. Attendance of military parades and drills are incorporated during this phase. This could create missed opportunities from the clinical learning as students are expected to leave the clinical setting for this purpose. Three focus group sessions were conducted and the experiences of the students, as narrated by themselves, yielded valuable insights. The researcher wrote field notes and assisted with the management of the audio tapes for easy retrieval of information. Data was analysed by the researcher, independent of the cocoder. Two themes relating to the PENs’ learning experiences emerged from the data analysed: (1 facilitators of clinical learning, (2 and barriers to clinical learning. The findings obtained depicted those factors which facilitated and obstructed student learning. These findings made it possible for the researcher to make recommendations concerning positive interventions which could be taken to

  2. Colon cancer modulation by a diabetic environment: A single institutional experience

    OpenAIRE

    Prieto, Isabel; del Puerto-Nevado, Laura; Gonzalez, Nieves; Portal-Nu?ez, Sergio; Zazo, Sandra; Corton, Marta; Minguez, Pablo; Gomez-Guerrero, Carmen; Arce, Jose Miguel; Sanz, Ana Belen; Mas, Sebastian; Aguilera, Oscar; Alvarez-Llamas, Gloria; Esbrit, Pedro; Ortiz, Alberto

    2017-01-01

    Background Multiple observational studies suggest an increased risk of colon cancer in patients with diabetes mellitus (DM). This can theoretically be the result of an influence of the diabetic environment on carcinogenesis or the tumor biologic behavior. Aim To gain insight into the influence of a diabetic environment on colon cancer characteristics and outcomes. Material and methods Retrospective analysis of clinical records in an academic tertiary care hospital with detailed analysis of 81...

  3. Patients’ experience of important factors in the healthcare environment in oncology care

    Directory of Open Access Journals (Sweden)

    Helle Wijk

    2013-08-01

    Full Text Available Background and objective. The aim of this study was to describe what factors of the healthcare environment are perceived as being important to patients in oncology care. Design. A qualitative design was adopted using focus group interviews. Setting and participants. The sample was 11 patients with different cancer diagnoses in an oncology ward at a university hospital in west Sweden. Results. Analysis of the patients’ perceptions of the environment indicated a complex entity comprising several aspects. These came together in a structure consisting of three main categories: safety, partnership with the staff, and physical space. The care environment is perceived as a complex entity, made up of several physical and psychosocial aspects, where the physical factors are subordinated by the psychosocial factors. It is clearly demonstrated that the patients’ primary desire was a psychosocial environment where they were seen as a unique person; the patients wanted opportunities for good encounters with staff, fellow patients, and family members, supported by a good physical environment; and the patients valued highly a place to withdraw and rest. Conclusions. This study presents those attributes that are valued by cancer patients as crucial and important for the support of their well-being and functioning. The results show that physical aspects were subordinate to psychosocial factors, which emerged strongly as being the most important in a caring environment.

  4. Neighborhood Environments and Physical Activity: A Longitudinal Study of Adolescents in a Natural Experiment.

    Science.gov (United States)

    Nicosia, Nancy; Datar, Ashlesha

    2018-05-01

    Experimental and quasi-experimental evidence on the relationship between adolescents' physical activity and their physical activity environments is scarce. This study provides natural experimental evidence using within-person longitudinal variation in physical activity environments resulting from the compulsory re-assignment of military families to new installations, termed permanent changes of station. Adolescents in Army families (N=749) reported usual weekly minutes of moderate and vigorous physical activity in 2013-2015. Objective measures of the physical activity environment, including the number of fitness and recreation facilities within 2 miles, were constructed for adolescents' neighborhoods using GIS methods. In 2017, individual-level fixed-effects models with and without a comparison group estimated the relationship between usual weekly minutes of physical activity and physical activity environments among permanent changes of station movers using within-person variation. Increases in opportunities for physical activity were significantly and positively associated with increases in total (p<0.05) and vigorous physical activity (p<0.05) among adolescents who experienced permanent changes of station moves. The relationships were statistically significant for permanent changes of station movers living off-installation (p<0.05) and hence subject to greater variation in physical activity environments and those with more time to adjust to their new environments (p<0.05). Significant findings persisted when broader measures of physical activity environments were utilized. The decline in physical activity and alarming obesity levels during adolescence suggest that this age may represent an important opportunity to address the obesity epidemic. This study provides evidence that increasing opportunities for physical activity may be an important pathway to improving their levels of physical activity and, consequently, obesity. Copyright © 2018 American Journal of

  5. In-air and pressurized water reactor environment fatigue experiments of 316 stainless steel to study the effect of environment on cyclic hardening

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish, E-mail: smohanty@anl.gov; Soppet, William K., E-mail: soppet@anl.gov; Majumdar, Saurindranath, E-mail: majumdar@anl.gov; Natesan, Krishnamurti, E-mail: natesan@anl.gov

    2016-05-15

    Argonne National Laboratory (ANL), under the sponsorship of Department of Energy's Light Water Reactor Sustainability (LWRS) program, is trying to develop a mechanistic approach for more accurate life estimation of LWR components. In this context, ANL has conducted many fatigue experiments under different test and environment conditions on type 316 stainless steel (316 SS) material which is widely used in the US reactors. Contrary to the conventional S ∼ N curve based empirical fatigue life estimation approach, the aim of the present DOE sponsored work is to develop an understanding of the material ageing issues more mechanistically (e.g. time dependent hardening and softening) under different test and environmental conditions. Better mechanistic understanding will help develop computer-based advanced modeling tools to better extrapolate stress-strain evolution of reactor components under multi-axial stress states and hence help predict their fatigue life more accurately. Mechanics-based modeling of fatigue such as by using finite element (FE) tools requires the time/cycle dependent material hardening properties. Presently such time-dependent material hardening properties are hardly available in fatigue modeling literature even under in-air conditions. Getting those material properties under PWR environment, are even harder. Through this work we made preliminary attempt to generate time/cycle dependent stress-strain data both under in-air and PWR water conditions for further study such as for possible development of material models and constitutive relations for FE model implementation. Although, there are open-ended possibility to further improve the discussed test methods and related material estimation techniques we anticipate that the data presented in this paper will help the metal fatigue research community particularly, the researchers who are dealing with mechanistic modeling of metal fatigue such as using FE tools. In this paper the fatigue

  6. Creating Supportive Learning Environments: Experiences of Lesbian and Gay-Parented Families in South African Schools

    Science.gov (United States)

    Breshears, Diana; Lubbe-De Beer, Carien

    2016-01-01

    Through in-depth interviews with 21 parents and 12 children in lesbian/gay-parented families, we explored the experiences of this unique family form in South African schools. Specifically, families reflected on their positive and negative experiences in the children's education and used these reflections to offer advice to teachers and…

  7. Coherent operation of detector systems and their readout electronics in a complex experiment control environment

    Energy Technology Data Exchange (ETDEWEB)

    Koestner, Stefan [CERN (Switzerland)], E-mail: koestner@mpi-halle.mpg.de

    2009-09-11

    With the increasing size and degree of complexity of today's experiments in high energy physics the required amount of work and complexity to integrate a complete subdetector into an experiment control system is often underestimated. We report here on the layered software structure and protocols used by the LHCb experiment to control its detectors and readout boards. The experiment control system of LHCb is based on the commercial SCADA system PVSS II. Readout boards which are outside the radiation area are accessed via embedded credit card sized PCs which are connected to a large local area network. The SPECS protocol is used for control of the front end electronics. Finite state machines are introduced to facilitate the control of a large number of electronic devices and to model the whole experiment at the level of an expert system.

  8. Learning your way in a city: experience and gender differences in configurational knowledge of one’s environment

    Directory of Open Access Journals (Sweden)

    Maartje ede Goede

    2015-04-01

    Full Text Available Males tend to outperform females in their knowledge of relative and absolute distances in spatial layouts and environments. It is unclear yet in how far these differences are innate or develop through life. The aim of the present study was to investigate whether gender differences in configurational knowledge for a natural environment might be modulated by experience. In order to examine this possibility, distance as well as directional knowledge of the city of Utrecht in the Netherlands was assessed in male and female inhabitants who had different levels of familiarity with this city. Experience affected the ability to solve difficult distance knowledge problems, but only for females. While the quality of the spatial representation of metric distances improved with more experience, this effect was not different for males and females. In contrast directional configurational measures did show a main gender effect but no experience modulation. In general, it seems that we obtain different configurational aspects according to different experiential time schemes. Moreover, the results suggest that experience may be a modulating factor in the occurrence of gender differences in configurational knowledge, though this seems dependent on the type of measurement. It is discussed in how far proficiency in mental rotation ability and spatial working memory accounts for these differences.

  9. Learning your way in a city: experience and gender differences in configurational knowledge of one’s environment

    Science.gov (United States)

    De Goede, Maartje; Postma, Albert

    2015-01-01

    Males tend to outperform females in their knowledge of relative and absolute distances in spatial layouts and environments. It is unclear yet in how far these differences are innate or develop through life. The aim of the present study was to investigate whether gender differences in configurational knowledge for a natural environment might be modulated by experience. In order to examine this possibility, distance as well as directional knowledge of the city of Utrecht in the Netherlands was assessed in male and female inhabitants who had different levels of familiarity with this city. Experience affected the ability to solve difficult distance knowledge problems, but only for females. While the quality of the spatial representation of metric distances improved with more experience, this effect was not different for males and females. In contrast directional configurational measures did show a main gender effect but no experience modulation. In general, it seems that we obtain different configurational aspects according to different experiential time schemes. Moreover, the results suggest that experience may be a modulating factor in the occurrence of gender differences in configurational knowledge, though this seems dependent on the type of measurement. It is discussed in how far proficiency in mental rotation ability and spatial working memory accounts for these differences. PMID:25914663

  10. Hacking the hospital environment: young adults designing youth-friendly hospital rooms together with young people with cancer experiences.

    Science.gov (United States)

    Boisen, Kirsten A; Boisen, Anne; Thomsen, Stine Legarth; Matthiesen, Simon Meggers; Hjerming, Maiken; Hertz, Pernille Grarup

    2015-12-09

    There is a need for youth-friendly hospital environments as the ward environment may affect both patient satisfaction and health outcomes. To involve young people in designing youth-friendly ward environment. We arranged a design competition lasting 42 h (Hackathon). Students in architecture, design, engineering, communication and anthropology participated (27 young adults) - forming eight groups. Adolescents and young adults (AYA) with current or former cancer experience participated as sparring partners. We provided workspace and food during the weekend. The groups presented their products to a jury and relevant stakeholders. The groups created eight unique design concepts. The young designers were extremely flexible listening to ideas and experiences from the young patients, which led to common features including individual and flexible design, privacy in two-bed wardrooms and social contact with other hospitalized AYA. The winning project included an integrated concept for both wardrooms and the AYA day room, including logos and names for the rooms and an 'energy wall' in the day room. A hackathon event was an effective mode of youth participation. The design concepts and ideas were in line with current evidence regarding pleasing hospital environment and youth-friendly inpatient facilities and may be applicable to other young patients.

  11. Smart Environments for Collaborative Design, Implementation, and Interpretation of Scientific Experiments

    NARCIS (Netherlands)

    van der Vet, P.E.; Kulyk, Olga Anatoliyivna; Wassink, I.; Fikkert, F.W.; Rauwerda, Han; van Dijk, Elisabeth M.A.G.; van der Veer, Gerrit C.; Breit, Timo; Huang, Thomas S.; Nijholt, Antinus; Pantic, Maja; Pentland, Alex

    2007-01-01

    Ambient intelligence promises to enable humans to smoothly interact with their environment, mediated by computer technology. In the literature on ambient intelligence, empirical scientists are not often mentioned. Yet they form an interesting target group for this technology. In this position paper,

  12. New grid based test bed environment for carrying out ad-hoc networking experiments

    CSIR Research Space (South Africa)

    Johnson, D

    2006-09-01

    Full Text Available and the third is to do analysis on a real test bed network which has implemented the ad-hoc networking protocol. This paper concerns the third option. Most researchers who have done work on test bed environments have used either indoor Wifi inter-office links...

  13. A metacomputing environment for demanding applications: design, implementation, experiments and business benefit

    NARCIS (Netherlands)

    Meliones, A.N.; Varvarigou, T.A.; Tsagronis, P.; Emmen, A.; Barosan, I.

    1999-01-01

    The paper describes the design, implementation, and use of a commercial metacomputing environment for computationally intensive loosely-coupled parallel applications. Much weight has been laid on practical and commercialisation aspects, and on business benefit. This distinguishes this work from many

  14. Experience in Education Environment Virtualization within the Automated Information System "Platonus" (Kazakhstan)

    Science.gov (United States)

    Abeldina, Zhaidary; Moldumarova, Zhibek; Abeldina, Rauza; Makysh, Gulmira; Moldumarova, Zhuldyz Ilibaevna

    2016-01-01

    This work reports on the use of virtual tools as means of learning process activation. A good result can be achieved by combining the classical learning with modern computer technology. By creating a virtual learning environment and using multimedia learning tools one can obtain a significant result while facilitating the development of students'…

  15. Active Learning Environments with Robotic Tangibles: Children's Physical and Virtual Spatial Programming Experiences

    Science.gov (United States)

    Burleson, Winslow S.; Harlow, Danielle B.; Nilsen, Katherine J.; Perlin, Ken; Freed, Natalie; Jensen, Camilla Nørgaard; Lahey, Byron; Lu, Patrick; Muldner, Kasia

    2018-01-01

    As computational thinking becomes increasingly important for children to learn, we must develop interfaces that leverage the ways that young children learn to provide opportunities for them to develop these skills. Active Learning Environments with Robotic Tangibles (ALERT) and Robopad, an analogous on-screen virtual spatial programming…

  16. Paramedics' experiences of financial medicine practices in the pre-hospital environment. A pilot study

    Directory of Open Access Journals (Sweden)

    Craig Vincent-Lambert

    2016-12-01

    Conclusion: The results of this study are concerning as the actions of service providers described by the participants constitute gross violations of the ethical and professional guidelines for health care professionals. The authors recommend additional studies be conducted to further explore these findings and to establish the reasons for, and ways of, limiting financial medicine practices in the South African emergency care environment.

  17. Cross-national social work case analysis: learning from international experience within an electronic environment

    NARCIS (Netherlands)

    R. Kloppenburg; V. Gevorgianiene; V. Jakutiene; Peter Hendriks

    2008-01-01

    This article presents the results of a pilot of a cross-national learning process within the context of social work education. The pilot was carried out in the electronic environment by students from four European universities (Hogeschool Utrecht, Sheffield, Tartu and Vilnius). The analysis of the

  18. Systematic Work Environment Management: experiences from implementation in Swedish small-scale enterprises.

    Science.gov (United States)

    Gunnarsson, Kristina; Andersson, Ing-Marie; Rosén, Gunnar

    2010-01-01

    Small-scale enterprises face difficulties in fulfilling the regulations for organising Systematic Work Environment Management. This study compared three groups of small-scale manufacturing enterprises with and without support for implementing the provision. Two implementation methods, supervised and network method, were used. The third group worked according to their own ideas. Twenty-three enterprises participated. The effects of the implementation were evaluated after one year by semi-structured dialogue with the manager and safety representative. Each enterprise was classified on compliance with ten demands concerning the provision. The work environment was estimated by the WEST-method. Impact of the implementation on daily work was also studied. At the follow-up, the enterprises in the supervised method reported slightly more improvements in the fulfilment of the demands in the provision than the enterprises in the network method and the enterprises working on their own did. The effect of the project reached the employees faster in the enterprises with the supervised method. In general, the work environment improved to some extent in all enterprises. Extensive support to small-scale enterprises in terms of advise and networking aimed to fulfil the regulations of Systematic Work Environment Management had limited effect - especially considering the cost of applying these methods.

  19. Energy, environment, and health: what can we learn from the nuclear experience

    International Nuclear Information System (INIS)

    Richmond, C.R.

    1978-01-01

    The following topics are discussed: effects of coal vs. nuclear energy on health and environment; the effects of exposure to pollutants on morbidity and mortality; carcinogenesis; mutagenesis; teratogenesis; dose-response for chronic low-level exposures; establishment of standards for environmental pollutants; detection of environmental pollutants; and cost of protection against pollutants

  20. Exploring the Lived Experiences of Program Managers Regarding an Automated Logistics Environment

    Science.gov (United States)

    Allen, Ronald Timothy

    2014-01-01

    Automated Logistics Environment (ALE) is a new term used by Navy and aerospace industry executives to describe the aggregate of logistics-related information systems that support modern aircraft weapon systems. The development of logistics information systems is not always well coordinated among programs, often resulting in solutions that cannot…

  1. Virtual reality experiments linking social environment and psychosis: A pilot study

    NARCIS (Netherlands)

    Veling, W.; Brinkman, W.P.; Dorrestijn, E.; van der Gaag, M.

    2014-01-01

    Initial studies with healthy subjects and individuals with high risk for psychosis have suggested that virtual reality (VR) environments may be used to investigate social and psychological mechanisms of psychosis. One small study reported that VR can safely be used in individuals with current

  2. The retention characteristics of nonvolatile SNOS memory transistors in a radiation environment: Experiment and model

    International Nuclear Information System (INIS)

    McWhorter, P.J.; Miller, S.L.; Dellin, T.A.; Axness, C.L.

    1987-01-01

    Experimental data and a model to accurately and quantitatively predict the data are presented for retention of SNOS memory devices over a wide range of dose rates. A wide range of SNOS stack geometries are examined. The model is designed to aid in screening nonvolatile memories for use in a radiation environment

  3. Market Garden: a Simulation Environment for Research and User Experience in Smart Grids

    NARCIS (Netherlands)

    B.J. Liefers (Bart); F.N. Claessen (Felix); E.J. Pauwels (Eric); P.A.N. Bosman (Peter); J.A. La Poutré (Han)

    2014-01-01

    htmlabstractMarket Garden is a scalable research environment and demonstration tool, in which market mechanisms for smart energy systems and the interaction between end users, traders, system operators, and markets can be simulated. Users can create scenarios in a user-friendly editor in which a

  4. Experiences and Challenges of International Students in Technology-Rich Learning Environments

    Science.gov (United States)

    Habib, Laurence; Johannesen, Monica; Øgrim, Leikny

    2014-01-01

    This article presents a study of international students and their use of technology in a Scandinavian institution of Higher Education. A special emphasis is placed on patterns of use of a virtual learning environment (VLE) that is available to all the study programmes at the institution. Actor-Network Theory (ANT) is used as a theoretical approach…

  5. Creating a Learner-Centered Environment in Nursing Education: An Immersion Experience

    Science.gov (United States)

    Steiner, Susan H.; Floyd, Evelyn; Hewett, Beverly J.; Lewis, Nicole C.; Walker, Eldon H.

    2010-01-01

    A call for change in nursing education has been issued in order to prepare the nurse of the future in a changing health care delivery system with increasing complexity. The learning environment is changing, including the faculty role. Innovative research-based pedagogies are suggested as a way to challenge traditional nursing education. The…

  6. Nurses' Perceptions of Pediatric Intensive Care Unit Environment and Work Experience After Transition to Single-Patient Rooms.

    Science.gov (United States)

    Kudchadkar, Sapna R; Beers, M Claire; Ascenzi, Judith A; Jastaniah, Ebaa; Punjabi, Naresh M

    2016-09-01

    The architectural design of the pediatric intensive care unit may play a major role in optimizing the environment to promote patients' sleep while improving stress levels and the work experience of critical care nurses. To examine changes in nurses' perceptions of the environment of a pediatric critical care unit for promotion of patients' sleep and the nurses' work experience after a transition from multipatient rooms to single-patient rooms. A cross-sectional survey of nurses was conducted before and after the move to a new hospital building in which all rooms in the pediatric critical care unit were single-patient rooms. Nurses reported that compared with multipatient rooms, single-patient private rooms were more conducive to patients sleeping well at night and promoted a more normal sleep-wake cycle (P noise in single-patient rooms (33%) than in multipatient rooms (79%; P pediatric intensive care unit environment for promoting patients' sleep and the nurses' own work experience. ©2016 American Association of Critical-Care Nurses.

  7. Decision-Making in a Dynamic Environment: The Effects of Experience and Information Uncertainty

    National Research Council Canada - National Science Library

    Kobus, D

    2000-01-01

    .... Fifty-two Marines with varying amounts of command-post experience assessed the situation as it developed, determined tactical leverage points, formed a plan of action, and submitted battle orders...

  8. Experiments for detection of gaseous Po-210 originated from microbial activity in the environment

    International Nuclear Information System (INIS)

    Ishimoto, A.; Momoshima, N.

    2006-01-01

    We attempted to detect gaseous Po-210 (half-life 138d) emitted from organisms in the environment. Gaseous Po-210 was tried to collect in 0.5 M nitric acid solution after passing the atmospheric air through filters and a distilled water bubbler, which would remove aerosols existing in the air. The activity of Po-210 was determined by alpha spectrometry after radiochemical separation and electrolytic deposition of Po-210 on a silver disk. Twenty seven point four mBq of Po-210 was observed when 800 m 3 atmospheric air was sampled. Blank of Po-210 in regents and the sampling system was 4.9-6.8 mBq. The concentration of Po-210 observed in the atmospheric air was, thus about 5 times higher than the background; the results strongly support existence of gaseous Po-210 in the environment. (author)

  9. Experiences of simulated tracer dispersal studies using effluent discharges at Tarapur aquatic environment

    International Nuclear Information System (INIS)

    Sudheendran, V.; Baburajan, A.; Sawane, Pratibha; Rao, D.D.; Hegde, A.G.

    2007-01-01

    The nuclear complex in Tarapur, Maharashtra is a multi facility nuclear site comprising of power reactors and research facilities. Each facility has independent liquid effluent discharge line to Arabian Sea. Experimental studies were conducted to evaluate dilution factors in the aquatic environment using liquid effluent releases as tracer from one of the facilities. 3 H and 137 Cs radioisotopes present in the routine releases were used as simulated tracer nuclides. The dilution factors(D.F) observed for tritium were in the range of 20-20000 in a distance range of 10 m to 1500 m respectively and for 137 Cs the D.F. were in the range of 50 to 900 over a distance range of 10-200 m. The paper describes the analytical methodology and sampling scenarios and the results of dilution factors obtained for Tarapur aquatic environment. (author)

  10. Presence and User Experience in a Virtual Environment under the Influence of Ethanol: An Explorative Study.

    Science.gov (United States)

    Lorenz, Mario; Brade, Jennifer; Diamond, Lisa; Sjölie, Daniel; Busch, Marc; Tscheligi, Manfred; Klimant, Philipp; Heyde, Christoph-E; Hammer, Niels

    2018-04-23

    Virtual Reality (VR) is used for a variety of applications ranging from entertainment to psychological medicine. VR has been demonstrated to influence higher order cognitive functions and cortical plasticity, with implications on phobia and stroke treatment. An integral part for successful VR is a high sense of presence - a feeling of 'being there' in the virtual scenario. The underlying cognitive and perceptive functions causing presence in VR scenarios are however not completely known. It is evident that the brain function is influenced by drugs, such as ethanol, potentially confounding cortical plasticity, also in VR. As ethanol is ubiquitous and forms part of daily life, understanding the effects of ethanol on presence and user experience, the attitudes and emotions about using VR applications, is important. This exploratory study aims at contributing towards an understanding of how low-dose ethanol intake influences presence, user experience and their relationship in a validated VR context. It was found that low-level ethanol consumption did influence presence and user experience, but on a minimal level. In contrast, correlations between presence and user experience were strongly influenced by low-dose ethanol. Ethanol consumption may consequently alter cognitive and perceptive functions related to the connections between presence and user experience.

  11. Linking agriculture and environment: theoretical framework and experiences from developed and developing countries

    International Nuclear Information System (INIS)

    Siwar, C.; Hossain, E.

    2005-01-01

    Despite significantly contributing to country's overall economic development through providing employment for the people and supplying raw materials for agro- and resource based industrial development, agriculture is putting serious burden on the environment in the process of production and consumption of agricultural produce. It is the largest consumer and polluter of water resources and contributor of atmospheric pollution, land degradation and forest reduction. Agriculture-environmental relationship is complex and the relationship depends on the spatial and biophysical factors and country's level of economic development. This paper tried to document the linkages between agricultural practices and policies with environment. The channels, through which agriculture impacts the environment, is discussed. It is seen that multilateral trade liberalization in agriculture interacts with the domestic agricultural policy reforms to determine the environmental impacts of agriculture. It is seen that agricultural policy reforms and agricultural trade liberalization can have separate environmental effects in the developed and developing countries. A wide range of theoretical and empirical literatures are reviewed, in this paper, to understand the concepts, linkages and environmental problems. Finally, this paper ends up with the conclusion that integrating environmental considerations into domestic agricultural policies and implementing agro-environmental programmes may ensure the decline of environmental problems of agriculture in both the developed and developing countries. (author)

  12. Colon cancer modulation by a diabetic environment: A single institutional experience.

    Science.gov (United States)

    Prieto, Isabel; Del Puerto-Nevado, Laura; Gonzalez, Nieves; Portal-Nuñez, Sergio; Zazo, Sandra; Corton, Marta; Minguez, Pablo; Gomez-Guerrero, Carmen; Arce, Jose Miguel; Sanz, Ana Belen; Mas, Sebastian; Aguilera, Oscar; Alvarez-Llamas, Gloria; Esbrit, Pedro; Ortiz, Alberto; Ayuso, Carmen; Egido, Jesus; Rojo, Federico; Garcia-Foncillas, Jesus

    2017-01-01

    Multiple observational studies suggest an increased risk of colon cancer in patients with diabetes mellitus (DM). This can theoretically be the result of an influence of the diabetic environment on carcinogenesis or the tumor biologic behavior. To gain insight into the influence of a diabetic environment on colon cancer characteristics and outcomes. Retrospective analysis of clinical records in an academic tertiary care hospital with detailed analysis of 81 diabetic patients diagnosed of colon cancer matched with 79 non-diabetic colon cancer patients. The impact of streptozotocin-induced diabetes on the growth of colon cancer xenografts was studied in mice. The incidence of DM in 1,137 patients with colorectal cancer was 16%. The diabetic colon cancer cases and non-diabetic colon cancer controls were well matched for demographic and clinical variables. The ECOG Scale Performance Status was higher (worse) in diabetics (ECOG ≥1, 29.1% of controls vs 46.9% of diabetics, p = 0.02), but no significant differences were observed in tumor grade, adjuvant therapy, tumor site, lymphovascular invasion, stage, recurrence, death or cancer-related death. Moreover, no differences in tumor variables were observed between patients treated or not with metformin. In the xenograft model, tumor growth and histopathological characteristics did not differ between diabetic and nondiabetic animals. Our findings point towards a mild or negligible effect of the diabetes environment on colon cancer behavior, once cancer has already developed.

  13. Calculation to experiment comparison of SPND signals in various nuclear reactor environments

    Energy Technology Data Exchange (ETDEWEB)

    Barbot, Loic; Radulovic, Vladimir; Fourmentel, Damien [CEA, DEN, DER, Instrumentation, Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-Lez-Durance, (France); Snoj, Luka [Jozef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, (Slovenia); Tarchalski, Mikolaj [National Centre for Nuclear Research, ulica Andrzeja Soltana 7, 05-400 Otwock (Swierk), (Poland); Dewynter-Marty, Veronique [CEA, DEN, DANS, DRSN, SIREN, LESCI, Saclay, F-91191 Gif sur Yvette, (France); Malouch, Fadhel [CEA, DEN, DANS, DM2S, SERMA, Saclay, F-91191 Gif sur Yvette, (France)

    2015-07-01

    In the perspective of irradiation experiments in the future Jules Horowitz Reactor (JHR), the Instrumentation Sensors and Dosimetry Laboratory of CEA Cadarache (France) is developing a numerical tool for SPND design, simulation and operation. In the frame of the SPND numerical tool qualification, dedicated experiments have been performed both in the Slovenian TRIGA Mark II reactor (JSI) and very recently in the French CEA Saclay OSIRIS reactor, as well as a test of two detectors in the core of the Polish MARIA reactor (NCBJ). A full description of experimental set-ups and neutron-gamma calculations schemes are provided in the first part of the paper. Calculation to experiment comparison of the various SPNDs in the different reactors is thoroughly described and discussed in the second part. Presented comparisons show promising final results. (authors)

  14. Do Natural Experiments of Changes in Neighborhood Built Environment Impact Physical Activity and Diet? A Systematic Review.

    Science.gov (United States)

    MacMillan, Freya; George, Emma S; Feng, Xiaoqi; Merom, Dafna; Bennie, Andrew; Cook, Amelia; Sanders, Taren; Dwyer, Genevieve; Pang, Bonnie; Guagliano, Justin M; Kolt, Gregory S; Astell-Burt, Thomas

    2018-01-26

    Physical activity and diet are major modifiable risk factors for chronic disease and have been shown to be associated with neighborhood built environment. Systematic review evidence from longitudinal studies on the impact of changing the built environment on physical activity and diet is currently lacking. A systematic review of natural experiments of neighborhood built environment was conducted. The aims of this systematic review were to summarize study characteristics, study quality, and impact of changes in neighborhood built environment on physical activity and diet outcomes among residents. Natural experiments of neighborhood built environment change, exploring longitudinal impacts on physical activity and/or diet in residents, were included. From five electronic databases, 2084 references were identified. A narrative synthesis was conducted, considering results in relation to study quality. Nineteen papers, reporting on 15 different exposures met inclusion criteria. Four studies included a comparison group and 11 were pre-post/longitudinal studies without a comparison group. Studies reported on the impact of redeveloping or introducing cycle and/or walking trails ( n = 5), rail stops/lines ( n = 4), supermarkets and farmers' markets ( n = 4) and park and green space ( n = 2). Eight/15 studies reported at least one beneficial change in physical activity, diet or another associated health outcome. Due to limitations in study design and reporting, as well as the wide array of outcome measures reported, drawing conclusions to inform policy was challenging. Future research should consider a consistent approach to measure the same outcomes (e.g., using measurement methods that collect comparable physical activity and diet outcome data), to allow for pooled analyses. Additionally, including comparison groups wherever possible and ensuring high quality reporting is essential.

  15. Do Natural Experiments of Changes in Neighborhood Built Environment Impact Physical Activity and Diet? A Systematic Review

    Directory of Open Access Journals (Sweden)

    Freya MacMillan

    2018-01-01

    Full Text Available Physical activity and diet are major modifiable risk factors for chronic disease and have been shown to be associated with neighborhood built environment. Systematic review evidence from longitudinal studies on the impact of changing the built environment on physical activity and diet is currently lacking. A systematic review of natural experiments of neighborhood built environment was conducted. The aims of this systematic review were to summarize study characteristics, study quality, and impact of changes in neighborhood built environment on physical activity and diet outcomes among residents. Natural experiments of neighborhood built environment change, exploring longitudinal impacts on physical activity and/or diet in residents, were included. From five electronic databases, 2084 references were identified. A narrative synthesis was conducted, considering results in relation to study quality. Nineteen papers, reporting on 15 different exposures met inclusion criteria. Four studies included a comparison group and 11 were pre-post/longitudinal studies without a comparison group. Studies reported on the impact of redeveloping or introducing cycle and/or walking trails (n = 5, rail stops/lines (n = 4, supermarkets and farmers’ markets (n = 4 and park and green space (n = 2. Eight/15 studies reported at least one beneficial change in physical activity, diet or another associated health outcome. Due to limitations in study design and reporting, as well as the wide array of outcome measures reported, drawing conclusions to inform policy was challenging. Future research should consider a consistent approach to measure the same outcomes (e.g., using measurement methods that collect comparable physical activity and diet outcome data, to allow for pooled analyses. Additionally, including comparison groups wherever possible and ensuring high quality reporting is essential.

  16. Designing Playful Interactive Installations for Urban Environments - The SwingScape Experience

    DEFF Research Database (Denmark)

    Grønbæk, Kaj; Kortbek, Karen Johanne; Christensen, Claus Møller

    2012-01-01

    . The design issues include: creating playful and collective interaction, making a familiar swing interaction simulate the experience of a music mixing board, providing gentle integration of multimedia (light and sound) in the atmosphere of an urban space, and finally making installations robust and safe...... at an urban playground. The objectives of SwingScape are to encourage physical activity as well as creating a playful and social experience in an urban space. The interaction techniques include movement sensors built into swings, LED lights, and an ambient loudspeaker system covering approx. 180 square meters...

  17. Radiation education using local environment. Educational experiment using Misasa spring water

    International Nuclear Information System (INIS)

    Nakamura, Mariko; Esaka, Takao; Kamata, Masahiro

    2005-01-01

    Hoping that use of natural radioactivity as teaching materials helps learners to understand the existence of radiation in nature, the authors developed several kinds of safe and inexpensive experiments for elementary and junior high school education using hot spring water taken from Misasa, situated in Tottori prefecture, Japan. Here, they report the details of experimental procedure to observe the radioactive equilibrium between Rn 222 released from the hot spring water and its daughters as well as the decay after isolation from Rn 222. The experiment needs no hazardous chemicals nor Bunsen burners, and can be carried out in normal classrooms without any special apparatus. (S. Ohno)

  18. Spectroscopic Evolution of Disintegrating Planetesimals: Minute to Month Variability in the Circumstellar Gas Associated with WD 1145+017

    Energy Technology Data Exchange (ETDEWEB)

    Redfield, Seth; Cauley, P. Wilson; Duvvuri, Girish M. [Astronomy Department and Van Vleck Observatory, Wesleyan University, Middletown, CT 06459 (United States); Farihi, Jay [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Parsons, Steven G. [Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH (United Kingdom); Gänsicke, Boris T., E-mail: sredfield@wesleyan.edu [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2017-04-10

    With the recent discovery of transiting planetary material around WD 1145+017, a critical target has been identified that links the evolution of planetary systems with debris disks and their accretion onto the star. We present a series of observations, five epochs over a year, taken with Keck and the VLT, which for the first time show variability of circumstellar absorption in the gas disk surrounding WD 1145+017 on timescales of minutes to months. Circumstellar absorption is measured in more than 250 lines of 14 ions among 10 different elements associated with planetary composition, e.g., O, Mg, Ca, Ti, Cr, Mn, Fe, and Ni. Broad circumstellar gas absorption with a velocity spread of 225 km s{sup −1} is detected, but over the course of a year blueshifted absorption disappears, while redshifted absorption systematically increases. A correlation of equivalent width and oscillator strength indicates that the gas is not highly optically thick (median τ ≈ 2). We discuss simple models of an eccentric disk coupled with magnetospheric accretion to explain the basic observed characteristics of these high-resolution and high signal-to-noise observations. Variability is detected on timescales of minutes in the two most recent observations, showing a loss of redshifted absorption for tens of minutes, coincident with major transit events and consistent with gas hidden behind opaque transiting material. This system currently presents a unique opportunity to learn how the gas causing the spectroscopic, circumstellar absorption is associated with the ongoing accretion evidenced by photospheric contamination, as well as the transiting planetary material detected in photometric observations.

  19. Exploring the circumstellar disk-like structure of the B[e] supergiant LHA 120-S 73

    Czech Academy of Sciences Publication Activity Database

    Torres, A.F.; Cidale, L.S.; Kraus, Michaela; Arias, M.L.; Maravelias, Grigorios; Borges Fernandes, M.; Vallverdú, R.

    2016-01-01

    Roč. 58, č. 1 (2016), s. 120-122 E-ISSN 1669-9521 R&D Projects: GA MŠk(CZ) 7AMB14AR017; GA MŠk LG14013 Institutional support: RVO:67985815 Keywords : stars * early-type * circumstellar matter Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics http://www.astronomiaargentina.org.ar/b58/2016baaa...58...120T.pdf

  20. The Environment for Professional Interaction and Relevant Practical Experience in AACSB-Accredited Accounting Programs.

    Science.gov (United States)

    Arlinghaus, Barry P.

    2002-01-01

    Responses from 276 of 1,128 faculty at Association to Advance Collegiate Schools of Business-accredited schools indicated that 231 were certified; only 96 served in professional associations; large numbers received financial support for professional activities, but only small numbers felt involvement or relevant experience (which are required for…

  1. Hyperfine interaction with polarized atomic environment - the nuclear tilted-foil experiment

    International Nuclear Information System (INIS)

    Niv, Y.

    1985-01-01

    The nuclear tilted-foil experimental field has matured from the early time-integral measurements to the current multifoil time-differential precession and polarization configurations, leading to a wide range of measurements - magnetic moments, quadrupole moments and parity-non-conservation. The physical basis of these experiments is discussed and experimental results are reviewed. (Auth.)

  2. Motivating and achievement-eliciting pop-ups in online environments: A user experience perspective

    NARCIS (Netherlands)

    Bittner, Jenny; Zondervan, Robin

    2015-01-01

    The aim of the present research was to develop pop-up windows that motivate users and evoke a positive user experience. Several variants of achievement eliciting pop-ups were designed and tested on a real business-website. A pre-test examined the effectiveness of 24 combinations of pictures and

  3. Pre-Service Post Graduate Teachers' First Time Experience with Constructivist Learning Environment (CLE) Using MOODLE

    Science.gov (United States)

    Boopathiraj, C.; Chellamani, K.

    2015-01-01

    The aim of this study is to enlighten and discuss Post Graduate student teachers' first time experiences and their level of satisfaction with the use of Moodle Learning Management System (LMS) during their "Research Methods in Education" course offered online. This study investigated 30 pre-service Post Graduate student teachers' to…

  4. Investigating the Key Attributes to Enhance Students' Learning Experience in 21st Century Class Environment

    Science.gov (United States)

    Leow, Fui-Theng; Neo, Mai; Hew, Soon Hin

    2016-01-01

    The 21st century marks the beginning of digital age with the extensive use of digital media, mobile devices, and Internet resources. Recent studies found that this digital era has expanded the landscape of student experiences, and educational technologies as well as increased the educator's awareness on embracing technologies to promote effective…

  5. Laser Light Scattering, from an Advanced Technology Development Program to Experiments in a Reduced Gravity Environment

    Science.gov (United States)

    Meyer, William V.; Tscharnuter, Walther W.; Macgregor, Andrew D.; Dautet, Henri; Deschamps, Pierre; Boucher, Francois; Zuh, Jixiang; Tin, Padetha; Rogers, Richard B.; Ansari, Rafat R.

    1994-01-01

    Recent advancements in laser light scattering hardware are described. These include intelligent single card correlators; active quench/active reset avalanche photodiodes; laser diodes; and fiber optics which were used by or developed for a NASA advanced technology development program. A space shuttle experiment which will employ aspects of these hardware developments is previewed.

  6. Experiences with automatic N and P measurements of an activated sludge process in a research environment

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard; Temmink, H.

    1996-01-01

    Some of the advantages of on-line automatic measurement of ammonia, nitrate and phosphate for studying activated sludge systems are pointed out with the help of examples of batch experiments. Sample taking is performed by cross-flow filtration and measurement of all three analytes is performed by...

  7. Changing expression of vertebrate immunity genes in an anthropogenic environment: a controlled experiment.

    Science.gov (United States)

    Hablützel, Pascal I; Brown, Martha; Friberg, Ida M; Jackson, Joseph A

    2016-09-01

    The effect of anthropogenic environments on the function of the vertebrate immune system is a problem of general importance. For example, it relates to the increasing rates of immunologically-based disease in modern human populations and to the desirability of identifying optimal immune function in domesticated animals. Despite this importance, our present understanding is compromised by a deficit of experimental studies that make adequately matched comparisons between wild and captive vertebrates. We transferred post-larval fishes (three-spined sticklebacks), collected in the wild, to an anthropogenic (captive) environment. We then monitored, over 11 months, how the systemic expression of immunity genes changed in comparison to cohort-matched wild individuals in the originator population (total n = 299). We found that a range of innate (lyz, defbl2, il1r-like, tbk1) and adaptive (cd8a, igmh) immunity genes were up-regulated in captivity, accompanied by an increase in expression of the antioxidant enzyme, gpx4a. For some genes previously known to show seasonality in the wild, this appeared to be reduced in captive fishes. Captive fishes tended to express immunity genes, including igzh, foxp3b, lyz, defbl2, and il1r-like, more variably. Furthermore, although gene co-expression patterns (analyzed through gene-by-gene correlations and mutual information theory based networks) shared common structure in wild and captive fishes, there was also significant divergence. For one gene in particular, defbl2, high expression was associated with adverse health outcomes in captive fishes. Taken together, these results demonstrate widespread regulatory changes in the immune system in captive populations, and that the expression of immunity genes is more constrained in the wild. An increase in constitutive systemic immune activity, such as we observed here, may alter the risk of immunopathology and contribute to variance in health in vertebrate populations exposed to

  8. Stress experiences in neighborhood and social environments (SENSE): a pilot study to integrate the quantified self with citizen science to improve the built environment and health.

    Science.gov (United States)

    Chrisinger, Benjamin W; King, Abby C

    2018-06-05

    models. Interactive data maps allowed participants to (1) reflect on data collected during the neighborhood walk, (2) see how EDA levels changed over the course of the walk in relation to objective neighborhood features (using basemap and DT app photos), and (3) compare their data to other participants along the same route. Participants identified a variety of social and environmental features that contributed to or detracted from their well-being. This initial investigation sets the stage for further research combining qualitative and quantitative data capture and interpretation to identify objective and perceived elements of the built environment influence our embodied experience in different settings. It provides a systematic process for simultaneously collecting multiple kinds of data, and lays a foundation for future statistical and spatial analyses in addition to more in-depth interpretation of how these responses vary within and between individuals.

  9. Monte Carlo simulations of the radiation environment for the CMS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mallows, S., E-mail: sophie.mallows@cern.ch [KIT, Karlsruhe (Germany); Azhgirey, I.; Bayshev, I. [IHEP, Protvino (Russian Federation); Bergstrom, I.; Cooijmans, T.; Dabrowski, A.; Glöggler, L.; Guthoff, M. [CERN, Geneva (Switzerland); Kurochkin, I. [IHEP, Protvino (Russian Federation); Vincke, H.; Tajeda, S. [CERN, Geneva (Switzerland)

    2016-07-11

    Monte Carlo radiation transport codes are used by the CMS Beam Radiation Instrumentation and Luminosity (BRIL) project to estimate the radiation levels due to proton–proton collisions and machine induced background. Results are used by the CMS collaboration for various applications: comparison with detector hit rates, pile-up studies, predictions of radiation damage based on various models (Dose, NIEL, DPA), shielding design, estimations of residual dose environment. Simulation parameters, and the maintenance of the input files are summarized, and key results are presented. Furthermore, an overview of additional programs developed by the BRIL project to meet the specific needs of CMS community is given.

  10. Monte Carlo simulations of the radiation environment for the CMS Experiment

    CERN Document Server

    AUTHOR|(CDS)2068566; Bayshev, I.; Bergstrom, I.; Cooijmans, T.; Dabrowski, A.; Glöggler, L.; Guthoff, M.; Kurochkin, I.; Vincke, H.; Tajeda, S.

    2016-01-01

    Monte Carlo radiation transport codes are used by the CMS Beam Radiation Instrumentation and Luminosity (BRIL) project to estimate the radiation levels due to proton-proton collisions and machine induced background. Results are used by the CMS collaboration for various applications: comparison with detector hit rates, pile-up studies, predictions of radiation damage based on various models (Dose, NIEL, DPA), shielding design, estimations of residual dose environment. Simulation parameters, and the maintenance of the input files are summarised, and key results are presented. Furthermore, an overview of additional programs developed by the BRIL project to meet the specific needs of CMS community is given.

  11. Analysis of the Experience of a Virtual Learning Environment Integration Into a Biochemistry Course Offered to Undergraduate Students

    Directory of Open Access Journals (Sweden)

    M.B. Espíndola

    2009-05-01

    Full Text Available As Information and Communication Technology (ICT becomes available in educational contexts, it is important that educators experiment different ways to deal with ICT tools in the teaching -learning process at the University basic sciences level. The challenge is to integrate ICT throughout the learning subjects in order to improve the quality of the learning process to students. This paper presents the results of an experience using a Virtual Learning Management System (VLMS, named Constructore, applied in the Biochemistry discipline at the Federal University of Rio de Janeiro (UFRJ for undergraduate medical students. Using Constructore, we developed a learning environment intended for integrating online activities and traditional course content. The course was focused on the integration of energy-yielding metabolism, exploring  metabolic adaptations in different physiological or pathological states such as starvation, diabetes and exercise. The course environment was structured with three modules, each of them presenting problem-based exercises to be answered after retrieving rele vant information in original scientific articles. Based on the analysis of  a semi-open questionnaire, the results provided evidence that the virtual environment stimulated students to critically read relevant scientific articles and to acquire skills to build and to integrate their knowledge through content association.

  12. Student nurses' experiences of the clinical learning environment in relation to the organization of supervision: a questionnaire survey.

    Science.gov (United States)

    Sundler, Annelie J; Björk, Maria; Bisholt, Birgitta; Ohlsson, Ulla; Engström, Agneta Kullén; Gustafsson, Margareta

    2014-04-01

    The aim was to investigate student nurses' experiences of the clinical learning environment in relation to how the supervision was organized. The clinical environment plays an essential part in student nurses' learning. Even though different models for supervision have been previously set forth, it has been stressed that there is a need both of further empirical studies on the role of preceptorship in undergraduate nursing education and of studies comparing different models. A cross-sectional study with comparative design was carried out with a mixed method approach. Data were collected from student nurses in the final term of the nursing programme at three universities in Sweden by means of a questionnaire. In general the students had positive experiences of the clinical learning environment with respect to pedagogical atmosphere, leadership style of the ward manager, premises of nursing, supervisory relationship, and role of the nurse preceptor and nurse teacher. However, there were significant differences in their ratings of the supervisory relationship (ppedagogical atmosphere (p 0.025) depending on how the supervision was organized. Students who had the same preceptor all the time were more satisfied with the supervisory relationship than were those who had different preceptors each day. Students' comments on the supervision confirmed the significance of the preceptor and the supervisory relationship. The organization of the supervision was of significance with regard to the pedagogical atmosphere and the students' relation to preceptors. Students with the same preceptor throughout were more positive concerning the supervisory relationship and the pedagogical atmosphere. © 2013.

  13. Entering 'A NEW REALM' of KIBO Payload Operations - Continuous efforts for microgravity experiment environment and lessons learned from real time experiment operations in KIBO -

    International Nuclear Information System (INIS)

    Sakagami, K; Goto, M; Matsumoto, S; Ohkuma, H

    2011-01-01

    On January 22nd, 2011(JST), KOUNOTORI2 (H-II Transfer Vehicle: HTV2) was successfully launched from Tanegashima Space Center toward the International Space Station (ISS) and two new JAXA payload racks, Kobairo rack and MSPR (Multi-purpose Small Payload Rack) were transferred to ISS/KIBO (Japanese Experiment Module: JEM). In addition to Saibo rack and Ryutai rack which are already in operation in KIBO, in total 4 Japanese experiment payload racks start operations in KIBO. Then KIBO payload operations embark on a new realm, full utilization phase. While the number and variety of microgravity experiments become increasing, simultaneous operation constraints should be considered to achieve multitask payload operations in ISS/KIBO and ever more complicated cooperative operations between crewmember and flight control team/science team are required. Especially for g-jitter improvement in ISS/KIBO, we have greatly advanced cooperative operations with crewmember in the recent increment based on the microgravity data analysis results. In this paper, newly operating Japanese experiment payloads characteristics and some methods to improve g-jitter environment are introduced from the front line of KIBO payload operations.

  14. Teaching Design in Adolescent Environments: Twinning Secondary and Tertiary Learning Experiences

    Directory of Open Access Journals (Sweden)

    David Jones

    2004-06-01

    Full Text Available Increasingly our landscape architecture teaching and educational pedagogies are facing an internationalisation in approach and expectation. We are positioned within a tertiary learning layer in a tripartite educational system for which each layer assumes certain expectations and outcomes. But their vertical linkages are unclear, and we incorrectly assume continuity of knowledge and skill learning strategies. It is a horizontally stratified teaching setting that we have to work within and while we can think of internationalisation as occurring within our level we need to appreciate that internationalisation is also occurring at the secondary level. This paper discusses the educational environment within which globalisation is occurring, and reviews a project model that builds bridges vertically between secondary and tertiary learning environments. The project displays possibilities in both secondary and tertiary educational sectors, but especially in enhancing and improving the design fluency of our annual incoming cohorts who often possess a naive understanding of built environmental design. Commencing in 1998 as an experimental project, it has been recognised at the South Australian state level as a forward-thinking initiative that has radically transformed secondary school Design teacher's perspectives as to educational possibilities, and substantially matured attitudes to landscape design by both suites of participants. As a consequence, it is an educational project that has experienced requests from numerous secondary schools around the State to participate.

  15. DISK DETECTIVE: DISCOVERY OF NEW CIRCUMSTELLAR DISK CANDIDATES THROUGH CITIZEN SCIENCE

    Energy Technology Data Exchange (ETDEWEB)

    Kuchner, Marc J.; McElwain, Michael; Padgett, Deborah L. [NASA Goddard Space Flight Center Exoplanets and Stellar Astrophysics Laboratory, Code 667 Greenbelt, MD 21230 (United States); Silverberg, Steven M.; Wisniewski, John P. [Homer L. Dodge Department of Physics and Astronomy The University of Oklahoma 440 W. Brooks St. Norman, OK 73019 (United States); Bans, Alissa S. [Valparaiso University, Department of Physics and Astronomy, Neils Science Center, 1610 Campus Drive East, Valparaiso, IN 46383 (United States); Bhattacharjee, Shambo [International Space University 1 Rue Jean-Dominique Cassini F-67400 Illkirch-Graffenstaden (France); Kenyon, Scott J. [Smithsonian Astrophysical Observatory 60 Garden Street Cambridge, MA 02138 (United States); Debes, John H. [Space Telescope Science Institute 3700 San Martin Dr. Baltimore, MD 21218 (United States); Currie, Thayne [National Astronomical Observatory of Japan 650 N A’ohokhu Place Hilo, HI 96720 (United States); García, Luciano [Observatorio Astronómico de Córdoba Universidad Nacional de Córdoba Laprida 854, X5000BGR, Córdoba (Argentina); Jung, Dawoon [Korea Aerospace Research Institute Lunar Exploration Program Office 169-84 Gwahak-ro, Yuseong-gu, Daejeon 34133 (Korea, Republic of); Lintott, Chris [Denys Wilkinson Building Keble Road Oxford, OX1 3RH (United Kingdom); Rebull, Luisa M. [Infrared Processing and Analaysis Center Caltech M/S 314-6 1200 E. California Blvd. Pasadena, CA 91125 (United States); Nesvold, Erika, E-mail: Marc.Kuchner@nasa.gov, E-mail: michael.w.mcelwain@nasa.gov, E-mail: deborah.l.padgett@nasa.gov, E-mail: carol.a.grady@nasa.gov, E-mail: silverberg@ou.edu, E-mail: wisniewski@ou.edu [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305 (United States); Collaboration: Disk Detective Collaboration; and others

    2016-10-20

    The Disk Detective citizen science project aims to find new stars with 22 μ m excess emission from circumstellar dust using data from NASA’s Wide-field Infrared Survey Explorer ( WISE ) mission. Initial cuts on the AllWISE catalog provide an input catalog of 277,686 sources. Volunteers then view images of each source online in 10 different bands to identify false positives (galaxies, interstellar matter, image artifacts, etc.). Sources that survive this online vetting are followed up with spectroscopy on the FLWO Tillinghast telescope. This approach should allow us to unleash the full potential of WISE for finding new debris disks and protoplanetary disks. We announce a first list of 37 new disk candidates discovered by the project, and we describe our vetting and follow-up process. One of these systems appears to contain the first debris disk discovered around a star with a white dwarf companion: HD 74389. We also report four newly discovered classical Be stars (HD 6612, HD 7406, HD 164137, and HD 218546) and a new detection of 22 μ m excess around the previously known debris disk host star HD 22128.

  16. SUPERNOVA PTF 09UJ: A POSSIBLE SHOCK BREAKOUT FROM A DENSE CIRCUMSTELLAR WIND

    International Nuclear Information System (INIS)

    Ofek, E. O.; Neill, J. D.; Kulkarni, S. R.; Forster, K.; Kasliwal, M. M.; Law, N.; Martin, C.; Quimby, R. M.; Rabinak, I.; Arcavi, I.; Waxman, E.; Gal-Yam, A.; Cenko, S. B.; Bloom, J. S.; Filippenko, A. V.; Poznanski, D.; Nugent, P. E.; Jacobsen, J.; Bildsten, L.; Howell, D. A.

    2010-01-01

    Type-IIn supernovae (SNe IIn), which are characterized by strong interaction of their ejecta with the surrounding circumstellar matter (CSM), provide a unique opportunity to study the mass-loss history of massive stars shortly before their explosive death. We present the discovery and follow-up observations of an SN IIn, PTF 09uj, detected by the Palomar Transient Factory (PTF). Serendipitous observations by Galaxy Evolution Explorer (GALEX) at ultraviolet (UV) wavelengths detected the rise of the SN light curve prior to the PTF discovery. The UV light curve of the SN rose fast, with a timescale of a few days, to a UV absolute AB magnitude of about -19.5. Modeling our observations, we suggest that the fast rise of the UV light curve is due to the breakout of the SN shock through the dense CSM (n ∼ 10 10 cm -3 ). Furthermore, we find that prior to the explosion the progenitor went through a phase of high mass-loss rate (∼0.1 M sun yr -1 ) that lasted for a few years. The decay rate of this SN was fast relative to that of other SNe IIn.

  17. Intracluster dust, circumstellar shells, and the wavelength dependence of polarization in orion

    International Nuclear Information System (INIS)

    Breger, M.

    1977-01-01

    The wavelength dependence of polarization of 21 polarized stars near the Orion Nebula has been measured. Most stars fit the standard interstellar law. The wavelength of maximum linear polarization, lambda/sub max/, ranges from normal values to 0.71μm. The polarimetric, spectroscopic, and photometric data support a normal reddening law (Rapprox. =3) for most Orion stars, and present evidence for unusually large grain sizes in front of some Orion stars. For the stars BR 545 and BR 885 large values of lambda/sub max/ are associated with unusually large values of total to selective extinction.A division of the observed polarization into intracluster dust and circumstellar shell components shows that the presence of shells does not usually lead to linear polarization in the optical wavelength region. Also, no association of polarization with known light variability could be found. The nature of the intracluster dust clouds is discussed briefly.The results of searches for circular polarization as well as short-period variability are presented in two appendices

  18. Measurement of Circumstellar Disk Sizes in the Upper Scorpius OB Association with ALMA

    Science.gov (United States)

    Barenfeld, Scott A.; Carpenter, John M.; Sargent, Anneila I.; Isella, Andrea; Ricci, Luca

    2017-12-01

    We present detailed modeling of the spatial distributions of gas and dust in 57 circumstellar disks in the Upper Scorpius OB Association observed with ALMA at submillimeter wavelengths. We fit power-law models to the dust surface density and CO J = 3–2 surface brightness to measure the radial extent of dust and gas in these disks. We found that these disks are extremely compact: the 25 highest signal-to-noise disks have a median dust outer radius of 21 au, assuming an {R}-1 dust surface density profile. Our lack of CO detections in the majority of our sample is consistent with these small disk sizes assuming the dust and CO share the same spatial distribution. Of seven disks in our sample with well-constrained dust and CO radii, four appear to be more extended in CO, although this may simply be due to the higher optical depth of the CO. Comparison of the Upper Sco results with recent analyses of disks in Taurus, Ophiuchus, and Lupus suggests that the dust disks in Upper Sco may be approximately three times smaller in size than their younger counterparts, although we caution that a more uniform analysis of the data across all regions is needed. We discuss the implications of these results for disk evolution.

  19. The Physics and Chemistry of Oxygen-Rich Circumstellar Envelopes as Traced by Simple Molecules

    Science.gov (United States)

    Wong, Ka Tat

    2018-04-01

    The physics and chemistry of the circumstellar envelopes (CSEs) of evolved stars are not fully understood despite decades of research. This thesis addresses two issues in the study of the CSEs of oxygen-rich (O-rich) evolved stars. In the first project, the ammonia (NH3) chemistry of O-rich stars is investigated with multi-wavelength observations; in the second project, the extended atmosphere and inner wind of the archetypal asymptotic giant branch (AGB) star o Ceti (Mira) is studied with high-angular resolution observations. One of the long-standing mysteries in circumstellar chemistry is the perplexing overabundance of the NH3 molecule. NH3 in O-rich evolved stars has been found in much higher abundance, by several orders of magnitude, than that expected in equilibrium chemistry. Several mechanisms have been suggested in the literature to explain this high NH3 abundance, including shocks in the inner wind, photodissociation of nitrogen by interstellar ultraviolet radiation, and nitrogen enrichment in stellar nucleosynthesis; however, none of these suggestions can fully explain the abundances of NH3 and various other molecular species in the CSEs of O-rich stars. In order to investigate the distribution of NH3 in O-rich CSEs, observations of the spectral lines of NH3 from a diverse sample of evolved stars and in different wavelength regimes are necessary. In this thesis, the NH3 line emission and absorption from four O-rich stars are studied. These targets include the AGB star IK Tauri, the pre-planetary nebula OH 231.8+4.2, the red supergiant VY Canis Majoris, and the yellow hypergiant IRC +10420. The amount of NH3 observational data has increased drastically thanks to the recent advancement of instrumentation. Observations of NH3 rotational line emission at submillimetre/far-infrared wavelengths were possible with the Herschel Space Observatory (2009–2013). The new wideband correlator in the upgraded Karl G. Janksy Very Large Array (VLA) provided data of

  20. IUE observations of circumstellar emission from the late-type variable R AQR (M6 + pec)

    Science.gov (United States)

    Hobbs, R. W.; Michalitsianos, A. G.; Kafatos, M.

    1981-01-01

    The IUE observations of R Aqr (M7 + pec) obtained in low dispersion are discussed with particular reference to circumstellar emission. Strong permitted, semiforbidden, and forbidden emission lines are seen, superimposed on a bright ultraviolet continuum. It is deduced that the strong emission line spectrum that involves C III, C IV, Si III, (0 II) and (0 III) probably arises from a dense compact nebula the size of which is comparable to the orbital radius of the binary system of which R Aqr is the primary star. The low excitation emission lines of Fe II, Mg II, 0 I, and Si II probably a white dwarf, comparable to or somewhat brighter than the Sun, since such a star can produce enough ionizing photons to excite the continuum and emission line spectrum and yet be sufficiently faint as to escape detection by direct observation. The UV continuum is attributed to Balmer recombination from the dense nebula and not to blackbody emission from the hot companion.

  1. THE FIRST DETERMINATION OF THE VISCOSITY PARAMETER IN THE CIRCUMSTELLAR DISK OF A Be STAR

    Energy Technology Data Exchange (ETDEWEB)

    Carciofi, Alex C.; Bjorkman, Jon E.; Haubois, Xavier [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao 1226, Cidade Universitaria, 05508-900, Sao Paulo, SP (Brazil); Otero, Sebastian A. [American Association of Variable Star Observers, 49 Bay State Road, Cambridge, MA 02138 (United States); Okazaki, Atsuo T. [Faculty of Engineering, Hokkai-Gakuen University, Toyohira-ku, Sapporo 062-8605 (Japan); Stefl, Stanislav; Rivinius, Thomas [European Organisation for Astronomical Research in the Southern Hemisphere, Casilla 19001, Santiago 19 (Chile); Baade, Dietrich, E-mail: carciofi@usp.br, E-mail: jon@physics.utoledo.edu [European Organisation for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild-Str. 2, 85748 Garching bei Muenchen (Germany)

    2012-01-15

    Be stars possess gaseous circumstellar decretion disks, which are well described using standard {alpha}-disk theory. The Be star 28 CMa recently underwent a long outburst followed by a long period of quiescence, during which the disk dissipated. Here we present the first time-dependent models of the dissipation of a viscous decretion disk. By modeling the rate of decline of the V-band excess, we determine that the viscosity parameter {alpha} = 1.0 {+-} 0.2, corresponding to a mass injection rate M-dot =(3.5{+-}1.3) Multiplication-Sign 10{sup -8} M{sub Sun} yr{sup -1}. Such a large value of {alpha} suggests that the origin of the turbulent viscosity is an instability in the disk whose growth is limited by shock dissipation. The mass injection rate is more than an order of magnitude larger than the wind mass-loss rate inferred from UV observations, implying that the mass injection mechanism most likely is not the stellar wind, but some other mechanism.

  2. Structures, Bonding, and Energetics of Potential Triatomic Circumstellar Molecules Containing Group 15 and 16 Elements.

    Science.gov (United States)

    Turner, Walter E; Agarwal, Jay; Schaefer, Henry F

    2015-12-03

    The recent discovery of PN in the oxygen-rich shell of the supergiant star VY Canis Majoris points to the formation of several triatomic molecules involving oxygen, nitrogen, and phosphorus; these are also intriguing targets for main-group synthetic inorganic chemistry. In this research, high-level ab initio electronic structure computations were conducted on the potential circumstellar molecule OPN and several of its heavier group 15 and 16 congeners (SPN, SePN, TePN, OPP, OPAs, and OPSb). For each congener, four isomers were examined. Optimized geometries were obtained with coupled cluster theory [CCSD(T)] using large Dunning basis sets [aug-cc-pVQZ, aug-cc-pV(Q+d)Z, and aug-cc-pVQZ-PP], and relative energies were determined at the complete basis set limit of CCSDT(Q) from focal point analyses. The linear phosphorus-centered molecules were consistently the lowest in energy of the group 15 congeners by at least 6 kcal mol(-1), resulting from double-triple and single-double bond resonances within the molecule. The linear nitrogen-centered molecules were consistently the lowest in energy of the group 16 congeners by at least 5 kcal mol(-1), due to the electronegative central nitrogen atom encouraging electron delocalization throughout the molecule. For OPN, OPP, and SPN, anharmonic vibrational frequencies and vibrationally corrected rotational constants are predicted; good agreement with available experimental data is observed.

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

    Science.gov (United States)

    Edwards, Jessica L.; Ziurys, Lucy

    2014-06-01

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

  4. A CHARA ARRAY SURVEY OF CIRCUMSTELLAR DISKS AROUND NEARBY Be-TYPE STARS

    International Nuclear Information System (INIS)

    Touhami, Y.; Gies, D. R.; McAlister, H. A.; Matson, R.

    2013-01-01

    We report on a high angular resolution survey of circumstellar disks around 24 northern sky Be stars. The K-band continuum survey was made using the CHARA Array long baseline interferometer (baselines of 30-331 m). The interferometric visibilities were corrected for the flux contribution of stellar companions in those cases where the Be star is a member of a known binary or multiple system. For those targets with good (u, v) coverage, we used a four-parameter Gaussian elliptical disk model to fit the visibilities and to determine the axial ratio, position angle, K-band photospheric flux contribution, and angular diameter of the disk's major axis. For the other targets with relatively limited (u, v) coverage, we constrained the axial ratio, inclination angle, and/or disk position angle where necessary in order to resolve the degeneracy between possible model solutions. We also made fits of the ultraviolet and infrared spectral energy distributions (SEDs) to estimate the stellar angular diameter and infrared flux excess of each target. The mean ratio of the disk diameter (measured in K-band emission) to stellar diameter (from SED modeling) is 4.4 among the 14 cases where we reliably resolved the disk emission, a value which is generally lower than the disk size ratio measured in the higher opacity Hα emission line. We estimated the equatorial rotational velocity from the projected rotational velocity and disk inclination for 12 stars, and most of these stars rotate close to or at the critical rotational velocity.

  5. THE INCIDENCE OF NON-SPHERICAL CIRCUMSTELLAR ENVELOPES IN ASYMPTOTIC GIANT BRANCH STARS

    International Nuclear Information System (INIS)

    Politano, Michael; Taam, Ronald E.

    2011-01-01

    The relative occurrence of asymmetric structures in the circumstellar envelopes (CSEs) of asymptotic giant branch (AGB) stars in detached binary star systems is studied based on a population synthesis method. The effects of envelope shaping by the gravitational interaction of the companion on an outflowing stellar wind are incorporated using previously derived empirical fits to numerical simulations. It is shown that significant asymmetries in the CSE, characterized by a ratio of the density in the equatorial direction relative to the polar direction, can exceed 10 for AGB stars characterized by luminosities in the range of 1000-10, 000 L sun in systems with orbital separations of 3-30 AU and mass ratios of 0.25-1. The incidence of such systems relative to a present-day field population of AGB stars (single + binary) is estimated to be 1%-6%, depending upon input parameter choices. For more modest density contrasts exceeding a factor of two, the incidence increases to 4%-15%. With the advent of future high-resolution molecular line studies of CSEs with the Atacama Large Millimeter Array, it is anticipated that the number of AGB stars exhibiting detectable asymmetries will significantly increase.

  6. DISK DETECTIVE: DISCOVERY OF NEW CIRCUMSTELLAR DISK CANDIDATES THROUGH CITIZEN SCIENCE

    International Nuclear Information System (INIS)

    Kuchner, Marc J.; McElwain, Michael; Padgett, Deborah L.; Silverberg, Steven M.; Wisniewski, John P.; Bans, Alissa S.; Bhattacharjee, Shambo; Kenyon, Scott J.; Debes, John H.; Currie, Thayne; García, Luciano; Jung, Dawoon; Lintott, Chris; Rebull, Luisa M.; Nesvold, Erika

    2016-01-01

    The Disk Detective citizen science project aims to find new stars with 22 μ m excess emission from circumstellar dust using data from NASA’s Wide-field Infrared Survey Explorer ( WISE ) mission. Initial cuts on the AllWISE catalog provide an input catalog of 277,686 sources. Volunteers then view images of each source online in 10 different bands to identify false positives (galaxies, interstellar matter, image artifacts, etc.). Sources that survive this online vetting are followed up with spectroscopy on the FLWO Tillinghast telescope. This approach should allow us to unleash the full potential of WISE for finding new debris disks and protoplanetary disks. We announce a first list of 37 new disk candidates discovered by the project, and we describe our vetting and follow-up process. One of these systems appears to contain the first debris disk discovered around a star with a white dwarf companion: HD 74389. We also report four newly discovered classical Be stars (HD 6612, HD 7406, HD 164137, and HD 218546) and a new detection of 22 μ m excess around the previously known debris disk host star HD 22128.

  7. RESOLVING THE CIRCUMSTELLAR DISK AROUND THE MASSIVE PROTOSTAR DRIVING THE HH 80-81 JET

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco-Gonzalez, Carlos [Max-Planck-Institut fuer Radioastronomie (MPIfR), Auf dem Huegel 69, 53121 Bonn (Germany); Galvan-Madrid, Roberto [European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching (Germany); Anglada, Guillem; Osorio, Mayra [Instituto de Astrofisica de Andalucia, CSIC, Camino Bajo de Huetor 50, E-18008 Granada (Spain); D' Alessio, Paola; Rodriguez, Luis F. [Centro de Radioastronomia y Astrofisica UNAM, Apartado Postal 3-72 (Xangari), 58089 Morelia, Michoacan (Mexico); Hofner, Peter [Physics Department, New Mexico Tech, 801 Leroy Pl., Socorro, NM 87801 (United States); Linz, Hendrik [Max-Planck-Institut fuer Astronomie (MPIA), Koenigstuhl 17, 69117 Heidelberg (Germany); Araya, Esteban D., E-mail: carrasco@mpifr-bonn.mpg.de [Physics Department, Western Illinois University, 1 University Circle, Macomb, IL 61455 (United States)

    2012-06-20

    We present new high angular resolution observations toward the driving source of the HH 80-81 jet (IRAS 18162-2048). Continuum emission was observed with the Very Large Array at 7 mm and 1.3 cm, and with the Submillimeter Array at 860 {mu}m, with angular resolutions of {approx}0.''1 and {approx}0.''8, respectively. Submillimeter observations of the sulfur oxide (SO) molecule are reported as well. At 1.3 cm the emission traces the well-known radio jet, while at 7 mm the continuum morphology is quadrupolar and seems to be produced by a combination of free-free and dust emission. An elongated structure perpendicular to the jet remains in the 7 mm image after subtraction of the free-free contribution. This structure is interpreted as a compact accretion disk of {approx}200 AU radius. Our interpretation is favored by the presence of rotation in our SO observations observed at larger scales. The observations presented here add to the small list of cases where the hundred-AU scale emission from a circumstellar disk around a massive protostar has been resolved.

  8. On the Origin of the Spiral Morphology in the Elias 2–27 Circumstellar Disk

    Energy Technology Data Exchange (ETDEWEB)

    Meru, Farzana; Juhász, Attila; Ilee, John D.; Clarke, Cathie J.; Rosotti, Giovanni P.; Booth, Richard A., E-mail: farzana.meru@ast.cam.ac.uk, E-mail: juhasz@ast.cam.ac.uk, E-mail: jdilee@ast.cam.ac.uk [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2017-04-20

    The young star Elias 2–27 has recently been observed to posses a massive circumstellar disk with two prominent large-scale spiral arms. In this Letter, we perform three-dimensional Smoothed Particle Hydrodynamics simulations, radiative transfer modeling, synthetic ALMA imaging, and an unsharped masking technique to explore three possibilities for the origin of the observed structures—an undetected companion either internal or external to the spirals, and a self-gravitating disk. We find that a gravitationally unstable disk and a disk with an external companion can produce morphology that is consistent with the observations. In addition, for the latter, we find that the companion could be a relatively massive planetary-mass companion (≲10–13 M {sub Jup}) and located at large radial distances (between ≈300–700 au). We therefore suggest that Elias 2–27 may be one of the first detections of a disk undergoing gravitational instabilities, or a disk that has recently undergone fragmentation to produce a massive companion.

  9. Disk Detective: Discovery of New Circumstellar Disk Candidates Through Citizen Science

    Science.gov (United States)

    Kuchner, Marc J.; Silverberg, Steven M.; Bans, Alissa S.; Bhattacharjee, Shambo; Kenyon, Scott J.; Debes, John H.; Currie, Thayne; Garcia, Luciano; Jung, Dawoon; Lintott, Chris; hide

    2016-01-01

    The Disk Detective citizen science project aims to find new stars with 22 micron excess emission from circumstellar dust using data from NASAs Wide-field Infrared Survey Explorer (WISE) mission. Initial cuts on the AllWISE catalog provide an input catalog of 277,686 sources. Volunteers then view images of each source online in 10different bands to identify false positives (galaxies, interstellar matter, image artifacts, etc.). Sources that survive this online vetting are followed up with spectroscopy on the FLWO Tillinghast telescope. This approach should allow us to unleash the full potential of WISE for finding new debris disks and proto planetary disks. We announce a first list of 37 new disk candidates discovered by the project, and we describe our vetting and follow-up process. One of these systems appears to contain the first debris disk discovered around a star with a white dwarf companion: HD 74389. We also report four newly discovered classical Be stars (HD 6612, HD 7406, HD 164137,and HD 218546) and a new detection of 22 micron excess around the previously known debris disk host star HD 22128.

  10. The circumstellar shells and mass loss rates of four M supergiants

    International Nuclear Information System (INIS)

    Bernat, A.P.

    1977-01-01

    A reanalysis of the physical structure of the circumstellar gas shells of four bright M supergiants, Betelgeuse, Antares, α Herculis, and μ Cephei, has been undertaken. The observational data include old Hale Observatories plates, recent McDonald Struve telescope plates, and McDonald 2.7 m photoelectric scans. These data are analyzed in the full expanding spherical geometry formulation of the radiative transfer equation.The results of the present analysis indicate that column densities in the gas shells must be revised downward compared with the previous plane-parallel results. However, the physical extents of the shells are considerably larger than previously assumed. These extents are inferred through ionization modeling, Weymann's Ca II technique, and direct observation. Also inferred are schematic wavelength-dependent chromospheric color temperatures. These results lead to much larger mass loss rates (in the range 6.7 x 10 -7 to 4.2 x 10 -4 M/sub sun/ yr -2 ) than previously inferred. The influence of these large rates of mass loss on the evolution of both stars and the Galaxy is briefly discussed

  11. Strong late-time circumstellar interaction in the peculiar supernova iPTF14hls

    Science.gov (United States)

    Andrews, Jennifer E.; Smith, Nathan

    2018-06-01

    We present a moderate-resolution spectrum of the peculiar Type II supernova (SN) iPTF14hls taken on day 1153 after discovery. This spectrum reveals the clear signature of shock interaction with dense circumstellar material (CSM). We suggest that this CSM interaction may be an important clue for understanding the extremely unusual photometric and spectroscopic evolution seen over the first 600 d of iPTF14hls. The late-time spectrum shows a double-peaked intermediate-width H α line indicative of expansion speeds around 1000 km s-1, with the double-peaked shape hinting at a disc-like geometry in the CSM. If the CSM were highly asymmetric, perhaps in a disc or torus that was ejected from the star 3-6 yr prior to explosion, the CSM interaction could have been overrun and hidden below the SN ejecta photosphere from a wide range of viewing angles. In that case, CSM interaction luminosity would have been thermalized well below the photosphere, potentially sustaining the high luminosity without exhibiting the traditional observational signatures of strong CSM interaction (narrow H α emission and X-rays). Variations in density structure of the CSM could account for the multiple rebrightenings of the light curve. We propose that a canonical 1 × 1051 erg explosion energy with enveloped CSM interaction as seen in some recent SNe, rather than an entirely new explosion mechanism, may be adequate to explain the peculiar evolution of iPTF14hls.

  12. Effects of cutting parameters and machining environments on surface roughness in hard turning using design of experiment

    Science.gov (United States)

    Mia, Mozammel; Bashir, Mahmood Al; Dhar, Nikhil Ranjan

    2016-07-01

    Hard turning is gradually replacing the time consuming conventional turning process, which is typically followed by grinding, by producing surface quality compatible to grinding. The hard turned surface roughness depends on the cutting parameters, machining environments and tool insert configurations. In this article the variation of the surface roughness of the produced surfaces with the changes in tool insert configuration, use of coolant and different cutting parameters (cutting speed, feed rate) has been investigated. This investigation was performed in machining AISI 1060 steel, hardened to 56 HRC by heat treatment, using coated carbide inserts under two different machining environments. The depth of cut, fluid pressure and material hardness were kept constant. The Design of Experiment (DOE) was performed to determine the number and combination sets of different cutting parameters. A full factorial analysis has been performed to examine the effect of main factors as well as interaction effect of factors on surface roughness. A statistical analysis of variance (ANOVA) was employed to determine the combined effect of cutting parameters, environment and tool configuration. The result of this analysis reveals that environment has the most significant impact on surface roughness followed by feed rate and tool configuration respectively.

  13. Microbial degradation of crude oil in marine environments tested in a flask experiment

    International Nuclear Information System (INIS)

    Aldrett, Salvador; Bonner, James S.; Mills, Marc A.; Autenrieth, Robin L.; Stephens, Frank L.

    1997-01-01

    Thirteen different bioremediation products were evaluated for their effectiveness in biodegrading petroleum hydrocarbons. All 13 products tested in this experiment were listed on the NCP product schedule. Of these 13 products, 12 were bioaugmentation agents and one was a biostimulation agent. All the products were tested for toxicity levels initially, using standardized protocols. The products were sampled and analyzed three times over a 28-day period for most-probable number (MPN) of hydrocarbon degraders and total petroleum hydrocarbon as separate fractions. A subsample was analyzed for MPN, and the rest of the sample was extracted and fractionated in total saturated petroleum hydrocarbons (TsPH) and total aromatic petroleum hydrocarbons (TarPH). This experiment revealed that the petroleum hydrocarbons were biodegraded to an extent significantly greater than that achieved by the naturally occurring microorganisms. (author)

  14. Botanic garden as an environment for informal education: experience of Kaunas Botanical Garden

    OpenAIRE

    Jurkonis, Nerijus

    2017-01-01

    According to Willison (1994), botanic gardens have an obvious and vital role to play in conserving plants, but conservation cannot succeed without education. Kaunas botanical garden (KBG) of Vytautas Magnus University, Lithuania has experience in a diverse range of education activities: from traditional guided excursions which present botanical collections, to informal education for preschoolers and schoolchildren. KBG is a partner in the Lithuanian Academy of Science’s project for the ‘Devel...

  15. Working in international environment based on training experiences in Greece, Finland and Spain

    OpenAIRE

    Cierechowicz, Izabela

    2016-01-01

    In various places around the world management looks different and has other preferences or focuses. We could think if it is a matter of business, country or maybe person. Personally, I believe that the way how management is done depends on many reasons, however some are more obvious than the others. Based on my training experiences in Greece, Finland and Spain I could compare how different management can be. What is interesting, in each place everything worked perfectly in completely dif...

  16. Dataset of two experiments of the application of gamified peer assessment model into online learning environment MeuTutor

    Directory of Open Access Journals (Sweden)

    Thyago Tenório

    2017-06-01

    Full Text Available In this dataset, we present the collected data of two experiments with the application of the gamified peer assessment model into online learning environment MeuTutor to allow the comparison of the obtained results with others proposed models. MeuTutor is an intelligent tutoring system aims to monitor the learning of the students in a personalized way, ensuring quality education and improving the performance of its members (Tenório et al., 2016 [1]. The first experiment evaluated the effectiveness of the peer assessment model through metrics as final grade (result, time to correct the activities and associated costs. The second experiment evaluated the gamification influence into peer assessment model, analyzing metrics as access number (logins, number of performed activities and number of performed corrections. In this article, we present in table form for each metric: the raw data of each treatment; the summarized data; the application results of the normality test Shapiro–Wilk; the application results of the statistical tests T-Test and/or Wilcoxon. The presented data in this article are related to the article entitled “A gamified peer assessment model for on-line learning environments in a competitive context” (Tenório et al., 2016 [1].

  17. The Cumulative Disadvantages of Socially Toxic Family Environments: A Comparison of Early Life Experiences of Incarcerated Men and University Students

    Directory of Open Access Journals (Sweden)

    Joseph Michalski

    2017-12-01

    Full Text Available The paper examines the antecedents of criminal behavior through the process of retrospective family and life course histories in which incarcerated male inmates and male university students are compared. The main focus is on early childhood experiences and parental behaviors. The study data derive from intensive, face-to-face interviews with 38 men incarcerated for violent offences and a matched group of 66 men attending university at the same time. The interviews focus on the relative importance of adverse childhood experiences and linkages with adolescence. The interviews demonstrated that nearly four-fifths of the inmates experienced toxic family environments by the time they reached adolescence, as compared with only two of the university students. Qualitative analyses flesh out the major themes, experiences, and “risk factors” that helped shape the trajectories of both groups of men. The socially toxic family environments and sub-optimal parenting practices that most inmates endured produced long-term, adverse effects in reducing their capacities for resilience, forging healthy relationships with their peers, and remaining in school.

  18. Dataset of two experiments of the application of gamified peer assessment model into online learning environment MeuTutor.

    Science.gov (United States)

    Tenório, Thyago; Bittencourt, Ig Ibert; Isotani, Seiji; Pedro, Alan; Ospina, Patrícia; Tenório, Daniel

    2017-06-01

    In this dataset, we present the collected data of two experiments with the application of the gamified peer assessment model into online learning environment MeuTutor to allow the comparison of the obtained results with others proposed models. MeuTutor is an intelligent tutoring system aims to monitor the learning of the students in a personalized way, ensuring quality education and improving the performance of its members (Tenório et al., 2016) [1]. The first experiment evaluated the effectiveness of the peer assessment model through metrics as final grade (result), time to correct the activities and associated costs. The second experiment evaluated the gamification influence into peer assessment model, analyzing metrics as access number (logins), number of performed activities and number of performed corrections. In this article, we present in table form for each metric: the raw data of each treatment; the summarized data; the application results of the normality test Shapiro-Wilk; the application results of the statistical tests T -Test and/or Wilcoxon. The presented data in this article are related to the article entitled "A gamified peer assessment model for on-line learning environments in a competitive context" (Tenório et al., 2016) [1].

  19. Earth Radiation Budget Experiment (ERBE) Data Sets for Global Environment and Climate Change Studies

    Science.gov (United States)

    Bess, T. Dale; Carlson, Ann B.; Denn, Fredrick M.

    1997-01-01

    For a number of years there has been considerable interest in the earth's radiation budget (ERB) or energy balance, and entails making the best measurements possible of absorbed solar radiation, reflected shortwave radiation (RSW), thermal outgoing longwave radiation (OLR), and net radiation. ERB data are fundamental to the development of realistic climate models and studying natural and anthropogenic perturbations of the climate. Much of the interest and investigations in the earth's energy balance predated the age of earth-orbiting satellites (Hunt et al., 1986). Beginning in the mid 1960's earth-orbiting satellites began to play an important role in making measurements of the earth's radiation flux although much effort had gone into measuring ERB parameters prior to 1960 (House et al., 1986). Beginning in 1974 and extending until the present time, three different satellite experiments (not all operating at the same time) have been making radiation budget measurements almost continually in time. Two of the experiments were totally dedicated to making radiation budget measurements of the earth, and the other experiment flown on NOAA sun-synchronous AVHRR weather satellites produced radiation budget parameters as a by-product. The heat budget data from the AVHRR satellites began collecting data in June 1974 and have operated almost continuously for 23 years producing valuable data for long term climate monitoring.

  20. Designing experiments on thermal interactions by secondary-school students in a simulated laboratory environment

    Science.gov (United States)

    Lefkos, Ioannis; Psillos, Dimitris; Hatzikraniotis, Euripides

    2011-07-01

    Background and purpose: The aim of this study was to explore the effect of investigative activities with manipulations in a virtual laboratory on students' ability to design experiments. Sample Fourteen students in a lower secondary school in Greece attended a teaching sequence on thermal phenomena based on the use of information and communication technology, and specifically of the simulated virtual laboratory 'ThermoLab'. Design and methods A pre-post comparison was applied. Students' design of experiments was rated in eight dimensions; namely, hypothesis forming and verification, selection of variables, initial conditions, device settings, materials and devices used, process and phenomena description. A three-level ranking scheme was employed for the evaluation of students' answers in each dimension. Results A Wilcoxon signed-rank test revealed a statistically significant difference between the students' pre- and post-test scores. Additional analysis by comparing the pre- and post-test scores using the Hake gain showed high gains in all but one dimension, which suggests that this improvement was almost inclusive. Conclusions We consider that our findings support the statement that there was an improvement in students' ability to design experiments.

  1. Implementation experiences of ISO/IEEE11073 standard applied to new use cases for e-health environments.

    Science.gov (United States)

    Martinez, I; Escayola, J; Martinez-Espronceda, M; Serrano, L; Trigo, J D; Led, S; Garcia, J

    2009-01-01

    Recent advances in biomedical engineering and continuous technological innovations in last decade are promoting new challenges, especially in e-Health environments. In this context, the medical devices interoperability is one of the interest fields wherein these improvements require a standard-based design in order to achieve homogeneous solutions. Furthermore, the spreading of wearable devices, oriented to the paradigm of patient environment and supported by wireless technologies as Bluetooth or ZigBee, is bringing new medical use cases based on Ambient Assisted Living, home monitoring of elderly, heart failure, chronic, under palliative care or patients who have undergone surgery, urgencies and emergencies, or even fitness auto-control and health follow-up. In this paper, several implementation experiences based on ISO/IEEE11073 standard are detailed. These evolved e-Health services can improve the quality of the patient's care, increase the user's interaction, and assure these e-Health applications to be fully compatible with global telemedicine systems.

  2. Service experience and stress corrosion of Inconel 600 bellows expansion joints in turbine steam environments

    International Nuclear Information System (INIS)

    Kramer, L.D.; Michael, S.T.; Pement, F.W.

    The purpose of this paper is to discuss the service history of Inconel 600 expansion bellows, to illustrate a typical case of failure, propose S.C.C. mechanisms, and to rationalize the most probable mechanism. Inconel 600 is fully resistant to high-purity power plant steam (720 deg F maximum) for on-going service lifetimes which greatly exceed the incubation periods which are reported or postulated in the literature for delayed stress corrosion cracking in high-purity water tests (630-660 deg F). The only observed stress corrosion environments which are sufficiently rapidly deleterious to be consistent with failure lifetimes are molten NaOH in superheated steam or a very concentrated aqueous caustic solution containing silica contamination. (author)

  3. Experience in using workstations as hosts in an accelerator control environment

    International Nuclear Information System (INIS)

    Abola, A.; Casella, R.; Clifford, T.; Hoff, L.; Katz, R.; Kennell, S.; Mandell, S.; McBreen, E.; Weygand, D.P.

    1987-01-01

    A new control system has been used for light ion acceleration at the Alternating Gradient Synchrotron (AGS). The control system uses Apollo workstations in the dual role of console hardware computer and controls system host. It has been found that having a powerful dedicated CPU with a demand paging virtual memory OS featuring strong interprocess communication, mapped memory shared files, shared code, and multi-window capabilities, allows us to provide an efficient operation environment in which users may view and manage several control processes simultaneously. The same features which make workstations good console computers also provide an outstanding platform for code development. The software for the system, consisting of about 30K lines of ''C'' code, was developed on schedule, ready for light ion commissioning. System development is continuing with work being done on applications programs

  4. Experience in using workstations as hosts in an accelerator control environment

    International Nuclear Information System (INIS)

    Abola, A.; Casella, R.; Clifford, T.; Hoff, L.; Katz, R.; Kennell, S.; Mandell, S.; McBreen, E.; Weygand, D.P.

    1987-03-01

    A new control system has been used for light ion acceleration at the Alternating Gradient Synchrotron (AGS). The control system uses Apollo workstations in the dual role of console hardware computer and controls system host. It has been found that having a powerful dedicated CPU with a demand paging virtual memory OS featuring strong interprocess communication, mapped memory shared files, shared code, and multi-window capabilities, allows us to provide an efficient operation environment in which users may view and manage several control processes simultaneously. The same features which make workstations good console computers also provide an outstanding platform for code development. The software for the system, consisting of about 30K lines of ''C'' code, was developed on schedule, ready for light ion commissioning. System development is continuing with work being done on applications programs

  5. Integrating knowledge and control into hypermedia-based training environments: Experiments with HyperCLIPS

    Science.gov (United States)

    Hill, Randall W., Jr.

    1990-01-01

    The issues of knowledge representation and control in hypermedia-based training environments are discussed. The main objective is to integrate the flexible presentation capability of hypermedia with a knowledge-based approach to lesson discourse management. The instructional goals and their associated concepts are represented in a knowledge representation structure called a 'concept network'. Its functional usages are many: it is used to control the navigation through a presentation space, generate tests for student evaluation, and model the student. This architecture was implemented in HyperCLIPS, a hybrid system that creates a bridge between HyperCard, a popular hypertext-like system used for building user interfaces to data bases and other applications, and CLIPS, a highly portable government-owned expert system shell.

  6. Preliminary results of thermal igniter experiments in H2-air-steam environments

    International Nuclear Information System (INIS)

    Lowry, W.

    1981-01-01

    Thermal igniters (glow plugs), proposed by the Tennessee Valley Authority for intentional ignition of hydrogen in nuclear reactor containment, have been tested for functionability in mixtures of air, hydrogen, and steam. Test environments included 6% to 16% hydrogen concentrations in air, and 8%, 10%, and 12% hydrogen in mixtures with 30% and 40% steam fractions. All were conducted in a 10.6 ft 3 insulated pressure vessel. For all of these tests the glow plug successfully initiated combustion. Dry air/hydrogen tests exhibited a distinct tendency for complete combustion at hydrogen concentrations between 8% and 9%. Steam suppressed both peak pressures and completeness of combustion. No combustion could be initiated at or above a 50% steam fraction. Circulation of the mixture with a fan increased the completeness of combustion. The glow plug showed no evidence of performance degradation throughout the program

  7. Teaching and learning experiences in a collaborative distance-education environment.

    Science.gov (United States)

    Martin, Peter; Scheetz, Laura Temple

    2011-01-01

    The Great Plains Distance Education Alliance (Great Plains IDEA) emphasizes the importance of a collaborative environment for instructors and students in distance education. The authors highlight a number of important principles for distance-education programs and point out similarities and differences when compared to traditional face-face-to classes such as communication, classroom management, connectivity, and technical challenges. They summarize general topics concerning the faculty, the syllabus, office hours, the calendar, and announcements. Three essential lesson components are noted: an overview, the lesson itself, and supplemanetary material. The authors also take the student perspective, emphasizing the diversity of students, the importance of computer proficiency, and student interactions. Finally, they summarize a first round of course evaluations in the Great Plains IDEA gerontology master's program.

  8. Pan Eurasian EXperiment (PEEX) - towards a new multinational environment and climate research effort in Eurasia

    Science.gov (United States)

    Petäjä, Tuukka; Kulmala, Markku; Lappalainen, Hanna; Sipilä, Mikko; Sorvari, Sanna; Alekseychik, Pavel; Paramonov, Mikhail; Kerminen, Veli-Matti; Zilitinkevich, Sergej

    2013-04-01

    Boreal forests are a substantial source of greenhouse gases, biogenic volatile organic compounds (BVOCs) and natural aerosols, the critical atmospheric components related to climate change processes. A large fraction of boreal forests of the world is situated in Siberian region. Representative measurements of carbon dioxide (CO2) and methane (CH4) concentrations, BVOC emissions and aerosols production from Siberian are of special importance when estimating global budgets of climate change relevant factors. The scope of a new concept of the Pan Eurasian Experiment (PEEX) is to set up a process for planning of a large-scale, long-term, coordinated observations and modeling experiment in the Pan Eurasian region, especially to cover ground base, airborne and satellite observations together with global and regional models to find out different forcing and feedback mechanisms in the changing climate. University of Helsinki together with Finnish Meteorological institute are organizing the Pan-Eurasian Experiment and to gather all the European and Russian key players in the field of climate and Earth system science to plan the future research activities in the Pan-Eurasian region. In the European scale PEEX is part of the JPI Climate Fast Track Activity 1.3. "Changing cryosphere in the climate system - from observations to climate modeling". PEEX research topics are closely related the NordForsk's Top Research Initiative CRAICC - Cryosphere - atmosphere interaction in the changing Arctic climate. PEEX is also a central part of the ongoing the Finnish Cultural Foundation - Earth System modeling Working Group activity (2012-2013). PEEX scientific aims and future actions to develop Pan Eurasian research infrastructure can be linked to several EC and ESA funded activities aiming to develop next generation research infrastructures and data products: EU-FP7-ACTRIS-I3-project (Aerosols, Clouds, and Trace gases Research InfraStructure Network-project 2011-2015); ICOS a research

  9. Using Teleducation and Field Experiences to further the Understanding of Coastal Environments

    Science.gov (United States)

    Macko, S. A.; Szuba, T. A.; Shugart, H.

    2007-05-01

    This project is an outreach and education program with a partner in the K-12 schools at Accomack County on the Eastern Shore of Virginia. It endeavors to build a community knowledgeable of the importance the ocean plays daily in our lives, and our own impact on the ocean. It is an program built in stages that: 1) Establish high speed live interactive classes (teleducation) linkages with the Eastern Shore High Schools with earth science teachers enabling them to remotely participate in University of Virginia classes in Oceanography (designed on a faculty development basis or acquire NSTA certification in Earth Science Education, as well as participation by seniors in the Accomack Schools; 2) Establish field experiences for teachers and selected students that involve travel to both the Virginia Coast Reserve Long Term Ecological Research (VCR/LTER) Center, UVA to observe first- hand the science programs at those locations and participate in cutting edge coastal marine research efforts. These experiences improve student understanding of the ocean-atmosphere biogeophysical system and encourage students to explore the sciences as a field of study and possible vocation. Advanced high school students and science teachers from Accomack County Public Schools participated in an experience involving field and laboratory methods employed in a NSF-sponsored study of the coupled natural-human dynamics on the Eastern Shore of Virginia over the past 500 years (NSF-Biocomplexity). Students and teachers worked with researchers of the VCR facility in Oyster, VA, collected sediment cores from Chesapeake Bay tributaries, and traveled to the Organic Geochemistry Laboratory at UVA, in Charlottesville, VA to prepare and analyze samples for isotopic and palynological information. In a first of its kind connectivity, in June/July, 2006, using high speed internet connections, a summer class in Oceanography was live, interactively broadcast (teleducation) from UVA to Arcadia High School on

  10. Nuclear acceptance and the regulatory environment: hard lessons from American experience

    International Nuclear Information System (INIS)

    Rowden, M.A.

    1982-01-01

    This paper discusses the efforts of those involved in the American nuclear power programme to earn public acceptance from the outset. It points out that the excessively stringent protection measures and the preoccupation with a catastrophic accident have probably contributed to making the public wary of nuclear power. In the light of experience following the Three Mile Island accident there will probably be a more realistic approach in future and acceptable and comparative risks, coupled with cost benefit will be considered, rather than unattainable goals. (U.K.)

  11. Aiding the environment: the Australian Development Agency's experience of implementing an environmental management system

    International Nuclear Information System (INIS)

    Keen, Meg; Sullivan, Marjorie

    2005-01-01

    Aid agencies, like commercial businesses, are increasingly concerned with incorporating sound environmental management into their operations. Different approaches are being used to integrate sustainability into development assistance to ensure that environmental impacts are assessed and managed. One approach being used by AusAID, the Australian aid agency, is to implement an environmental management system (EMS) across program and project areas. This paper examines how AusAID has adapted the EMS approach to suit aid agency operations, and some of the lessons from the Australian experience

  12. New Educational Environments Aimed at Developing Intercultural Understanding While Reinforcing the Use of English in Experience-Based Learning

    Directory of Open Access Journals (Sweden)

    Leonard R. Bruguier

    2012-07-01

    Full Text Available New learning environments with communication and information tools are increasingly accessible with technology playing a crucial role in expanding and reconceptualizing student learning experiences. This paper reviews the outcome of an innovative course offered by four universities in three countries: Canada, the United States, and Mexico. Course objectives focused on broadening the understanding of indigenous and non-indigenous peoples primarily in relation to identity as it encouraged students to reflect on their own identity while improving their English skills in an interactive and experiential manner and thus enhancing their intercultural competence.

  13. Qualitative Data Gathering Challenges in a Politically Unstable Rural Environment: A Zimbabwean Experience

    Directory of Open Access Journals (Sweden)

    Tabitha Grace Mukeredzi

    2012-02-01

    Full Text Available Gaining access to participants in rural, politically unstable settings demands authority and consent not only from the participants and immediate line managers, but also from other players with interests in the research sites. This paper discusses data gathering experiences and challenges encountered during fieldwork for a PhD amidst a politically volatile situation in Zimbabwe in mid-2008. The article highlights the challenges encountered, how the researcher overcame some of them, and was stymied by others. Specifically, political challenges related to gaining access to schools and participants, which created time constraints and frustrations, fears and anxieties for the researcher. Issues of poor topography and interview space also emerged as other challenges. The paper proposes that the snags and surprises, the feelings of frustration, fear and anger that go with researching participants in politically unstable settings should not stall the research process but instead, handled with flexibility and patience, and used as motivation to continue. The experiences not only enhance the researcher's own reflexivity and reflectivity but also provide insights into the human conditions and actions as viewed from multiple perspectives.

  14. Experiences of using the Theoretical Domains Framework across diverse clinical environments: a qualitative study

    Science.gov (United States)

    Phillips, Cameron J; Marshall, Andrea P; Chaves, Nadia J; Jankelowitz, Stacey K; Lin, Ivan B; Loy, Clement T; Rees, Gwyneth; Sakzewski, Leanne; Thomas, Susie; To, The-Phung; Wilkinson, Shelley A; Michie, Susan

    2015-01-01

    Background The Theoretical Domains Framework (TDF) is an integrative framework developed from a synthesis of psychological theories as a vehicle to help apply theoretical approaches to interventions aimed at behavior change. Purpose This study explores experiences of TDF use by professionals from multiple disciplines across diverse clinical settings. Methods Mixed methods were used to examine experiences, attitudes, and perspectives of health professionals in using the TDF in health care implementation projects. Individual interviews were conducted with ten health care professionals from six disciplines who used the TDF in implementation projects. Deductive content and thematic analysis were used. Results Three main themes and associated subthemes were identified including: 1) reasons for use of the TDF (increased confidence, broader perspective, and theoretical underpinnings); 2) challenges using the TDF (time and resources, operationalization of the TDF) and; 3) future use of the TDF. Conclusion The TDF provided a useful, flexible framework for a diverse group of health professionals working across different clinical settings for the assessment of barriers and targeting resources to influence behavior change for implementation projects. The development of practical tools and training or support is likely to aid the utility of TDF. PMID:25834455

  15. Healthcare Providers' Formative Experiences with Race and Black Male Patients in Urban Hospital Environments.

    Science.gov (United States)

    Plaisime, Marie V; Malebranche, David J; Davis, Andrea L; Taylor, Jennifer A

    2017-12-01

    We explored health providers' formative personal and professional experiences with race and Black men as a way to assess their potential influence on interactions with Black male patients. Utilizing convenience sampling with snowballing techniques, we identified healthcare providers in two urban university hospitals. We compared Black and White providers' experiences based on race and level of training. We used the Gardener's Tale to conceptualize how racism may lead to racial health disparities. A semi-structured interview guide was used to conduct in-person interviews (n = 16). Using the grounded theory approach, we conducted three types of coding to examine data patterns. We found two themes reflective of personally mediated racism: (1) perception of Black males accompanied by two subthemes (a) biased care and (b) fear and discomfort and (2) cognitive dissonance. While this latter theme is more reflective of Jones's internalized racism level, we present its results because its novelty is compelling. Perception of Black males and cognitive dissonance appear to influence providers' approaches with Black male patients. This study suggests the need to develop initiatives and curricula in health professional schools that address provider racial bias. Understanding the dynamics operating in the patient-provider encounter enhances the ability to address and reduce health disparities.

  16. PICTURE: a sounding rocket experiment for direct imaging of an extrasolar planetary environment

    Science.gov (United States)

    Mendillo, Christopher B.; Hicks, Brian A.; Cook, Timothy A.; Bifano, Thomas G.; Content, David A.; Lane, Benjamin F.; Levine, B. Martin; Rabin, Douglas; Rao, Shanti R.; Samuele, Rocco; Schmidtlin, Edouard; Shao, Michael; Wallace, J. Kent; Chakrabarti, Supriya

    2012-09-01

    The Planetary Imaging Concept Testbed Using a Rocket Experiment (PICTURE 36.225 UG) was designed to directly image the exozodiacal dust disk of ǫ Eridani (K2V, 3.22 pc) down to an inner radius of 1.5 AU. PICTURE carried four key enabling technologies on board a NASA sounding rocket at 4:25 MDT on October 8th, 2011: a 0.5 m light-weight primary mirror (4.5 kg), a visible nulling coronagraph (VNC) (600-750 nm), a 32x32 element MEMS deformable mirror and a milliarcsecond-class fine pointing system. Unfortunately, due to a telemetry failure, the PICTURE mission did not achieve scientific success. Nonetheless, this flight validated the flight-worthiness of the lightweight primary and the VNC. The fine pointing system, a key requirement for future planet-imaging missions, demonstrated 5.1 mas RMS in-flight pointing stability. We describe the experiment, its subsystems and flight results. We outline the challenges we faced in developing this complex payload and our technical approaches.

  17. Experiences of using the Theoretical Domains Framework across diverse clinical environments: a qualitative study.

    Science.gov (United States)

    Phillips, Cameron J; Marshall, Andrea P; Chaves, Nadia J; Jankelowitz, Stacey K; Lin, Ivan B; Loy, Clement T; Rees, Gwyneth; Sakzewski, Leanne; Thomas, Susie; To, The-Phung; Wilkinson, Shelley A; Michie, Susan

    2015-01-01

    The Theoretical Domains Framework (TDF) is an integrative framework developed from a synthesis of psychological theories as a vehicle to help apply theoretical approaches to interventions aimed at behavior change. This study explores experiences of TDF use by professionals from multiple disciplines across diverse clinical settings. Mixed methods were used to examine experiences, attitudes, and perspectives of health professionals in using the TDF in health care implementation projects. Individual interviews were conducted with ten health care professionals from six disciplines who used the TDF in implementation projects. Deductive content and thematic analysis were used. Three main themes and associated subthemes were identified including: 1) reasons for use of the TDF (increased confidence, broader perspective, and theoretical underpinnings); 2) challenges using the TDF (time and resources, operationalization of the TDF) and; 3) future use of the TDF. The TDF provided a useful, flexible framework for a diverse group of health professionals working across different clinical settings for the assessment of barriers and targeting resources to influence behavior change for implementation projects. The development of practical tools and training or support is likely to aid the utility of TDF.

  18. Gender differences in experiences of sexual harassment: data from a male-dominated environment.

    Science.gov (United States)

    Street, Amy E; Gradus, Jaimie L; Stafford, Jane; Kelly, Kacie

    2007-06-01

    The goal of this investigation was to examine gender differences in experiences of sexual harassment during military service and the negative mental health symptoms associated with these experiences. Female (n = 2,319) and male (n = 1,627) former reservists were surveyed about sexual harassment during their military service and current mental health symptoms. As expected, women reported a higher frequency of sexual harassment. Further, women had increased odds of experiencing all subtypes of sexual harassment. Being female conferred the greatest risk for experiencing the most serious forms of harassment. For both men and women, sexual harassment was associated with more negative current mental health. However, at higher levels of harassment, associations with some negative mental health symptoms were stronger for men than women. Although preliminary, the results of this investigation suggest that although women are harassed more frequently than men, clinicians must increase their awareness of the potential for sexual harassment among men in order to provide the best possible care to all victims of harassment. Copyright 2007 APA.

  19. Effects of different vegetation on temperature in an urban building environment. Micro-scale numerical experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Guenter [Hannover Univ. (Germany). Inst. fuer Meteorologie und Klimatologie

    2012-08-15

    A three-dimensional micro-scale model is used to study the effects of various greenery on temperature in a built-up environment. Green design elements like roofs and facades, lawns in courtyards and single trees are studied individually as well as in various combinations. Measures for comparison are temperatures at 2 m height and mean temperatures for the urban atmosphere up to the building height. Different types of greenery can reduce local temperatures up to 15 K during specific daytime hours. However, this extraordinary effect is restricted to a short time and especially to the direct surroundings, while an impact over larger distances is small. Roof and facade greenery have hardly any influence on temperature at the 2 m level but reduce daytime heating of the urban atmosphere to a minor degree, while the relevance of trees is more or less limited to the shadow effect. A significant decrease in urban temperatures can be achieved only with a large number of very different individual green elements. The largest effect on the urban atmosphere was simulated for a change in albedo resulting in a temperature decrease of some degrees around noon. (orig.)

  20. Enhancement of User Quality of Experience (QoE) for Service Migration in Context Aware Environment

    DEFF Research Database (Denmark)

    Saeed, Aamir

    condition, device resources utilization and user mobility may be outdated, and have potential to invoke an unnecessary migration which impacts the satisfaction level of user. Firstly, the work presented in this thesis propose a service migration framework (SMF) for designing application with migration...... decision for massively multiplayer online game server (MMOG) was simulated. Due to communication delay and load transfer delay, the shared context is often outdated, and may trigger unnecessary migration. A prediction based approach was presented, to use estimated future server state as additional context...... individual user responsiveness. In summary, the thesis identified core elements of migration process. The mapping of loss of user experience as QoE loss score value, provides a performance metric for measuring performance of migratory application. Furthermore, the impact of out dated information in dynamic...

  1. A Reliable and Distributed LIMS for Efficient Management of the Microarray Experiment Environment

    Directory of Open Access Journals (Sweden)

    Jin Hee-Jeong

    2007-03-01

    Full Text Available A microarray is a principal technology in molecular biology. It generates thousands of expressions of genotypes at once. Typically, a microarray experiment contains many kinds of information, such as gene names, sequences, expression profiles, scanned images, and annotation. So, the organization and analysis of vast amounts of data are required. Microarray LIMS (Laboratory Information Management System provides data management, search, and basic analysis. Recently, microarray joint researches, such as the skeletal system disease and anti-cancer medicine have been widely conducted. This research requires data sharing among laboratories within the joint research group. In this paper, we introduce a web based microarray LIMS, SMILE (Small and solid MIcroarray Lims for Experimenters, especially for shared data management. The data sharing function of SMILE is based on Friend-to-Friend (F2F, which is based on anonymous P2P (Peer-to-Peer, in which people connect directly with their “friends”. It only allows its friends to exchange data directly using IP addresses or digital signatures you trust. In SMILE, there are two types of friends: “service provider”, which provides data, and “client”, which is provided with data. So, the service provider provides shared data only to its clients. SMILE provides useful functions for microarray experiments, such as variant data management, image analysis, normalization, system management, project schedule management, and shared data management. Moreover, it connections with two systems: ArrayMall for analyzing microarray images and GENAW for constructing a genetic network. SMILE is available on http://neobio.cs.pusan.ac.kr:8080/smile.

  2. Connecting food environments and health through the relational nature of aesthetics: Gaining insight through the community gardening experience

    Science.gov (United States)

    Hale, James; Knapp, Corrine; Bardwell, Lisa; Buchenau, Michael; Marshall, Julie; Sancar, Fahriye; Litt, Jill S

    2011-01-01

    Current environmental and health challenges require us to identify ways to better align aesthetics, ecology, and health. At the local level, community gardens are increasingly praised for their therapeutic qualities. They also provide a lens through which we can explore relational processes that connect people, ecology and health. Using key-informant interview data, this research explores gardeners’ tactile, emotional, and value-driven responses to the gardening experience and how these responses influence health at various ecological levels (n=67 participants, 28 urban gardens). Our findings demonstrate that gardeners’ aesthetic experiences generate meaning that encourages further engagement with activities that may lead to positive health outcomes. Gardeners directly experience nearby nature by ‘getting their hands dirty’ and growing food. They enjoy the way vegetables taste and form emotional connections with the garden. The physical and social qualities of garden participation awaken the senses and stimulate a range of responses that influence interpersonal processes (learning, affirming, expressive experiences) and social relationships that are supportive of positive health-related behaviors and overall health. This research suggests that the relational nature of aesthetics, defined as the most fundamental connection between people and place, can help guide community designers and health planners when designing environment and policy approaches to improve health behaviors. PMID:21596466

  3. Connecting food environments and health through the relational nature of aesthetics: gaining insight through the community gardening experience.

    Science.gov (United States)

    Hale, James; Knapp, Corrine; Bardwell, Lisa; Buchenau, Michael; Marshall, Julie; Sancar, Fahriye; Litt, Jill S

    2011-06-01

    Current environmental and health challenges require us to identify ways to better align aesthetics, ecology, and health. At the local level, community gardens are increasingly praised for their therapeutic qualities. They also provide a lens through which we can explore relational processes that connect people, ecology and health. Using key-informant interview data, this research explores gardeners' tactile, emotional, and value-driven responses to the gardening experience and how these responses influence health at various ecological levels (n = 67 participants, 28 urban gardens). Our findings demonstrate that gardeners' aesthetic experiences generate meaning that encourages further engagement with activities that may lead to positive health outcomes. Gardeners directly experience nearby nature by 'getting their hands dirty' and growing food. They enjoy the way vegetables taste and form emotional connections with the garden. The physical and social qualities of garden participation awaken the senses and stimulate a range of responses that influence interpersonal processes (learning, affirming, expressive experiences) and social relationships that are supportive of positive health-related behaviors and overall health. This research suggests that the relational nature of aesthetics, defined as the most fundamental connection between people and place, can help guide community designers and health planners when designing environment and policy approaches to improve health behaviors. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Empowerment, environment and person-centred care: A qualitative study exploring the hospital experience for adults with cognitive impairment.

    Science.gov (United States)

    Prato, Laura; Lindley, Lyndsay; Boyles, Miriam; Robinson, Louise; Abley, Clare

    2018-01-01

    It is acknowledged that there are many challenges to ensuring a positive hospital experience for patients with cognitive impairment. The study ('Improving hospital care for adults with cognitive impairment') aimed to explore the positive and negative experiences of older adults with cognitive impairment (dementia and delirium) and their relatives and/or carers, during an acute hospital stay, from admission to discharge, using a qualitative, case study methodology. Six participants with cognitive impairment, eight relatives and 59 members of the health care team were recruited. Data was collected via ethnographic, observational periods at each stage of the hospital journey and through the use of semi-structured interviews with relatives, carers and health care staff including: medical staff; nursing staff; physiotherapists and ward managers. Interpretive phenomenological analysis was used to facilitate data analysis. 52 hours 55 minutes of ethnographic observations and 18 interviews with ward staff and relatives were undertaken. Three superordinate themes emerged from the data as crucial in determining the quality of the hospital experience: valuing the person; activities of empowerment and disempowerment and the interaction of environment with patient well-being. Whether the patient's hospital experience was positive or negative was powerfully influenced by family involvement and ward staff actions and communication. Participants identified a requirement for a ward based activity service for patients with cognitive impairment. Further research must be undertaken focusing on the development of ward based activities for patients with cognitive impairment, alongside a move towards care which explores measures to improve and expand relative involvement in hospital care.

  5. Experience with PACS in an ATM/Ethernet switched network environment.

    Science.gov (United States)

    Pelikan, E; Ganser, A; Kotter, E; Schrader, U; Timmermann, U

    1998-03-01

    Legacy local area network (LAN) technologies based on shared media concepts are not adequate for the growth of a large-scale picture archiving and communication system (PACS) in a client-server architecture. First, an asymmetric network load, due to the requests of a large number of PACS clients for only a few main servers, should be compensated by communication links to the servers with a higher bandwidth compared to the clients. Secondly, as the number of PACS nodes increases, the network throughout should not measurably cut production. These requirements can easily be fulfilled using switching technologies. Here asynchronous transfer mode (ATM) is clearly one of the hottest topics in networking because the ATM architecture provides integrated support for a variety of communication services, and it supports virtual networking. On the other hand, most of the imaging modalities are not yet ready for integration into a native ATM network. For a lot of nodes already joining an Ethernet, a cost-effective and pragmatic way to benefit from the switching concept would be a combined ATM/Ethernet switching environment. This incorporates an incremental migration strategy with the immediate benefits of high-speed, high-capacity ATM (for servers and high-sophisticated display workstations), while preserving elements of the existing network technologies. In addition, Ethernet switching instead of shared media Ethernet improves the performance considerably. The LAN emulation (LANE) specification by the ATM forum defines mechanisms that allow ATM networks to coexist with legacy systems using any data networking protocol. This paper points out the suitability of this network architecture in accordance with an appropriate system design.

  6. Evaluating pesticide effects on freshwater invertebrate communities in alpine environment: a model ecosystem experiment.

    Science.gov (United States)

    Ippolito, A; Carolli, M; Varolo, E; Villa, S; Vighi, M

    2012-10-01

    Pesticide loads in streams are potentially one of the most relevant stressors for macroinvertebrate communities. Nevertheless, real effects provoked at the community level are still largely unknown. Model ecosystems are frequently used as tools for the risk assessment of pesticides, especially for their regulation, however, they can be also applied to site-specific risk assessment in order to gain better understanding of the responses of aquatic ecosystems to chemical stress. In the present work, an experimental system was composed of 5 artificial streams that reproduced a mountain lotic environment under controlled conditions. This study was aimed to better understand, whether (and how) the biological community was influenced by pesticides pulse exposures. 5 mixture load events were simulated over the productive season (March-July 2010): biological community was regularly sampled and nominal concentrations of water were tested. The results were interpreted comparing the output of different metrics and statistical methodologies. The sensitivity of different metrics was analyzed considering single exposure events (maximum Toxic Units) as well as overall temporal trends. Results showed how some common taxonomic metrics (e.g. taxa richness, Shannon's index, total abundance of organisms, and the Extended Biotic Index) were not suitable to identify the effects of pesticides at community level. On the contrary EPT%, SPEAR(pesticide) and the Principal Response Curve methodology proved to be sensitive to this kind of stress, providing comparable results. Temporal trends of these metrics proved to be related to the concentration of chemicals. Remarkably, the first Principal Response Curve illustrates the trend followed by the most vulnerable species, while the second is more related to the trend of opportunistic species. A high potential risk for the invertebrate community was highlighted by a statistically significant decline of 40 points (comparison with the control) in

  7. Partitioning of alcohol ethoxylates and polyethylene glycols in the marine environment: Field samplings vs laboratory experiments

    Energy Technology Data Exchange (ETDEWEB)

    Traverso-Soto, Juan M. [Departamento de Química Física, Facultad de Ciencias del Mar y Ambientales, Campus de Excelencia Internacional del Mar (CEI-MAR), Universidad de Cádiz, Campus Río San Pedro s/n, Puerto Real, Cádiz 11510 (Spain); Brownawell, Bruce J. [School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794-5000 (United States); González-Mazo, Eduardo [Departamento de Química Física, Facultad de Ciencias del Mar y Ambientales, Campus de Excelencia Internacional del Mar (CEI-MAR), Universidad de Cádiz, Campus Río San Pedro s/n, Puerto Real, Cádiz 11510 (Spain); Lara-Martín, Pablo A., E-mail: pablo.lara@uca.es [Departamento de Química Física, Facultad de Ciencias del Mar y Ambientales, Campus de Excelencia Internacional del Mar (CEI-MAR), Universidad de Cádiz, Campus Río San Pedro s/n, Puerto Real, Cádiz 11510 (Spain)

    2014-08-15

    Nowadays, alcohol ethoxylates (AEOs) constitute the most important group of non-ionic surfactants, used in a wide range of applications such as household cleaners and detergents. Significant amounts of these compounds and their degradation products (polyethylene glycols, PEGs, which are also used for many other applications) reach aquatic environments, and are eliminated from the water column by degradation and sorption processes. This work deals with the environmental distribution of AEOs and PEGs in the Long Island Sound Estuary, a setting impacted by sewage discharges from New York City (NYC). The distribution of target compounds in seawater was influenced by tides, consistent with salinity differences, and concentrations in suspended solid samples ranged from 1.5 to 20.5 μg/g. The more hydrophobic AEOs were mostly attached to the particulate matter whereas the more polar PEGs were predominant in the dissolved form. Later, the sorption of these chemicals was characterized in the laboratory. Experimental and environmental sorption coefficients for AEOs and PEGs showed average values from 3607 to 164,994 L/kg and from 74 to 32,862 L/kg, respectively. The sorption data were fitted to a Freundlich isotherm model with parameters n and log K{sub F} between 0.8–1.2 and 1.46–4.39 L/kg, respectively. AEO and PEG sorptions on marine sediment were also found to be mostly not affected by changes in salinity. - Highlights: • AEO and PEG levels in estuaries are influenced by tides and suspended solids. • Sediment–water partition coefficients in the lab and in the field are comparable. • Sorption is depending on both hydrophilic and hydrophobic interactions. • Sorption data fits Freundlich isotherms, showing K{sub F} values from 29 to 24,892 L/kg. • Sorption is very weakly influenced by salinity changes.

  8. DNA Radiation Environments Program: Fall 1989 2-meter box experiments and analysis

    International Nuclear Information System (INIS)

    Santoro, R.T.

    1991-05-01

    This effort, sponsored by the Defense Nuclear Agency under the Radiation Environments Program, was carried out to obtain measured data for benchmarking MASH, the Monte Carlo Adjoint Code System. MASH was developed to replace the Vehicle Code System, VCS, that has been used by the Department of Defense and NATO for calculating neutron and gamma-ray radiation fields and shielding protection factors inside armored vehicles and structures from nuclear weapon radiation. Free-field data were obtained at distances of 170- and 400-meters from the APR while in-box measurements were made at 400 meters only. The box, included to obtain neutron and gamma-ray reduction factors, was a 2-meter cube configuration having 0.1016-m-thick steel walls. Calculated data were obtained using MASH by analysts from the Oak Ridge National Laboratory and Science Applications International Corporation. Calculated (C) results were compared with experimental (E) data in terms of C/E ratios. Free-field and in-box neutron kerma generally agreed within ±20%, although some C/E comparisons fell outside this range depending upon the detector against which the calculated data were compared. For those cases where the C/E ratio is marginal or unacceptable, problems in the detector systems were acknowledged to be principal cause of the discrepancy. Generally poor agreement (∼25-35%) was achieved among the C/E ratios for the free-field gamma-ray kerma at the 170- and 400-m locations while excellent (10%, or better) C/E values were obtained for the in-box conditions. The discrepancy for the free-field comparison was attributed to the failure by the analysts to include a tree line adjacent to the measurement site in the calculational geometry. C/E values for the neutron and gamma-ray reduction factors ranged from 1% to 23% depending on the detector. 4 refs., 2 figs., 14 tabs

  9. Impact of policy and built environment changes on obesity-related outcomes: a systematic review of naturally occurring experiments.

    Science.gov (United States)

    Mayne, S L; Auchincloss, A H; Michael, Y L

    2015-05-01

    Policies and changes to the built environment are promising targets for obesity prevention efforts and can be evaluated as 'natural'- or 'quasi'-experiments. This systematic review examined the use of natural- or quasi-experiments to evaluate the efficacy of policy and built environment changes on obesity-related outcomes (body mass index, diet or physical activity). PubMed (Medline) was searched for studies published 2005-2013; 1,175 abstracts and 115 papers were reviewed. Of the 37 studies included, 18 studies evaluated impacts on nutrition/diet, 17 on physical activity and 3 on body mass index. Nutrition-related studies found greater effects because of bans/restrictions on unhealthy foods, mandates offering healthier foods, and altering purchase/payment rules on foods purchased using low-income food vouchers compared with other interventions (menu labelling, new supermarkets). Physical activity-related studies generally found stronger impacts when the intervention involved improvements to active transportation infrastructure, longer follow-up time or measured process outcomes (e.g., cycling rather than total physical activity), compared with other studies. Only three studies directly assessed body mass index or weight, and only one (installing light-rail system) observed a significant effect. Studies varied widely in the strength of their design and studies with weaker designs were more likely to report associations in the positive direction. © 2015 World Obesity.

  10. Real behavior in virtual environments: psychology experiments in a simple virtual-reality paradigm using video games.

    Science.gov (United States)

    Kozlov, Michail D; Johansen, Mark K

    2010-12-01

    The purpose of this research was to illustrate the broad usefulness of simple video-game-based virtual environments (VEs) for psychological research on real-world behavior. To this end, this research explored several high-level social phenomena in a simple, inexpensive computer-game environment: the reduced likelihood of helping under time pressure and the bystander effect, which is reduced helping in the presence of bystanders. In the first experiment, participants had to find the exit in a virtual labyrinth under either high or low time pressure. They encountered rooms with and without virtual bystanders, and in each room, a virtual person requested assistance. Participants helped significantly less frequently under time pressure but the presence/absence of a small number of bystanders did not significantly moderate helping. The second experiment increased the number of virtual bystanders, and participants were instructed to imagine that these were real people. Participants helped significantly less in rooms with large numbers of bystanders compared to rooms with no bystanders, thus demonstrating a bystander effect. These results indicate that even sophisticated high-level social behaviors can be observed and experimentally manipulated in simple VEs, thus implying the broad usefulness of this paradigm in psychological research as a good compromise between experimental control and ecological validity.

  11. Grid heterogeneity in in-silico experiments: an exploration of drug screening using DOCK on cloud environments.

    Science.gov (United States)

    Yim, Wen-Wai; Chien, Shu; Kusumoto, Yasuyuki; Date, Susumu; Haga, Jason

    2010-01-01

    Large-scale in-silico screening is a necessary part of drug discovery and Grid computing is one answer to this demand. A disadvantage of using Grid computing is the heterogeneous computational environments characteristic of a Grid. In our study, we have found that for the molecular docking simulation program DOCK, different clusters within a Grid organization can yield inconsistent results. Because DOCK in-silico virtual screening (VS) is currently used to help select chemical compounds to test with in-vitro experiments, such differences have little effect on the validity of using virtual screening before subsequent steps in the drug discovery process. However, it is difficult to predict whether the accumulation of these discrepancies over sequentially repeated VS experiments will significantly alter the results if VS is used as the primary means for identifying potential drugs. Moreover, such discrepancies may be unacceptable for other applications requiring more stringent thresholds. This highlights the need for establishing a more complete solution to provide the best scientific accuracy when executing an application across Grids. One possible solution to platform heterogeneity in DOCK performance explored in our study involved the use of virtual machines as a layer of abstraction. This study investigated the feasibility and practicality of using virtual machine and recent cloud computing technologies in a biological research application. We examined the differences and variations of DOCK VS variables, across a Grid environment composed of different clusters, with and without virtualization. The uniform computer environment provided by virtual machines eliminated inconsistent DOCK VS results caused by heterogeneous clusters, however, the execution time for the DOCK VS increased. In our particular experiments, overhead costs were found to be an average of 41% and 2% in execution time for two different clusters, while the actual magnitudes of the execution time

  12. UV SURFACE ENVIRONMENT OF EARTH-LIKE PLANETS ORBITING FGKM STARS THROUGH GEOLOGICAL EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Rugheimer, S.; Sasselov, D. [Harvard Smithsonian Center for Astrophysics, 60 Garden st., 02138 MA Cambridge (United States); Segura, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, México (Mexico); Kaltenegger, L., E-mail: srugheimer@cfa.harvard.edu [Carl Sagan Institute, Cornell University, Ithaca, NY 14853 (United States)

    2015-06-10

    The UV environment of a host star affects the photochemistry in the atmosphere, and ultimately the surface UV environment for terrestrial planets and therefore the conditions for the origin and evolution of life. We model the surface UV radiation environment for Earth-sized planets orbiting FGKM stars in the circumstellar Habitable Zone for Earth through its geological evolution. We explore four different types of atmospheres corresponding to an early-Earth atmosphere at 3.9 Gyr ago and three atmospheres covering the rise of oxygen to present-day levels at 2.0 Gyr ago, 0.8 Gyr ago, and modern Earth. In addition to calculating the UV flux on the surface of the planet, we model the biologically effective irradiance, using DNA damage as a proxy for biological damage. We find that a pre-biotic Earth (3.9 Gyr ago) orbiting an F0V star receives 6 times the biologically effective radiation as around the early Sun and 3520 times the modern Earth–Sun levels. A pre-biotic Earth orbiting GJ 581 (M3.5 V) receives 300 times less biologically effective radiation, about 2 times modern Earth–Sun levels. The UV fluxes calculated here provide a grid of model UV environments during the evolution of an Earth-like planet orbiting a range of stars. These models can be used as inputs into photo-biological experiments and for pre-biotic chemistry and early life evolution experiments.

  13. UV SURFACE ENVIRONMENT OF EARTH-LIKE PLANETS ORBITING FGKM STARS THROUGH GEOLOGICAL EVOLUTION

    International Nuclear Information System (INIS)

    Rugheimer, S.; Sasselov, D.; Segura, A.; Kaltenegger, L.

    2015-01-01

    The UV environment of a host star affects the photochemistry in the atmosphere, and ultimately the surface UV environment for terrestrial planets and therefore the conditions for the origin and evolution of life. We model the surface UV radiation environment for Earth-sized planets orbiting FGKM stars in the circumstellar Habitable Zone for Earth through its geological evolution. We explore four different types of atmospheres corresponding to an early-Earth atmosphere at 3.9 Gyr ago and three atmospheres covering the rise of oxygen to present-day levels at 2.0 Gyr ago, 0.8 Gyr ago, and modern Earth. In addition to calculating the UV flux on the surface of the planet, we model the biologically effective irradiance, using DNA damage as a proxy for biological damage. We find that a pre-biotic Earth (3.9 Gyr ago) orbiting an F0V star receives 6 times the biologically effective radiation as around the early Sun and 3520 times the modern Earth–Sun levels. A pre-biotic Earth orbiting GJ 581 (M3.5 V) receives 300 times less biologically effective radiation, about 2 times modern Earth–Sun levels. The UV fluxes calculated here provide a grid of model UV environments during the evolution of an Earth-like planet orbiting a range of stars. These models can be used as inputs into photo-biological experiments and for pre-biotic chemistry and early life evolution experiments

  14. EXPERIENCE THE FORMATION OF THE INNOVATION ENVIRONMENT IN THE STATE INNOVATION STRATEGY OF CHINA

    Directory of Open Access Journals (Sweden)

    M. S. Reshetnikova

    2016-01-01

    Full Text Available Among main strategic goals of China in the second half of XX century was the creation of a superpower with an efficient economy, which occupies a leading position in the world. Modernization of the country was inextricably linked to the formation of its own self-sustaining innovation system. Using the experience of recognized innovation leaders such as the Soviet Union, France and the United States, China has transformed the elements of its innovation strategy, adjusting it to the circumstances of global innovative activity. The result of government policy was the creation of one of the world's largest national innovation system (NIS. Today China's NIS is a complex set of both public and private institutions, which are closely interrelated. Their joint activities focus on the creation, use and improvement of new and high technologies. The current NIS combines the features of both the administrative-command and market systems and components, folding under the influence of the major trends of global economy, especially the internationalization of innovation activities. Analysis of innovative development strategy pursued by China, allowed to define a distinct periodization that was influenced by the changes taking place in the global economy. The main steps of China's NIS development are the following: formation of incremental type innovation system, upgrading the innovation system, the shift from the strategy of "market in exchange for technology" to "interaction and integration into the world market" and the creation of its own high-tech products. The uniqueness of the political system and structure of economy impact on the state strategy in R&D and NIS, forming both the strengths and weaknesses. The analysis of China's government strategy of innovative development shows that it is significantly and deliberately worked on extensive scientific development indicators. However, this strategy did not lead to a breakthrough in basic research and the

  15. The experiences from implementing decision support technology to address water management plans in an operational environment

    Energy Technology Data Exchange (ETDEWEB)

    McArdle, S. [4DM Inc., Toronto, ON (Canada); Tonkin, C. [Ontario Power Generation Inc., Toronto, ON (Canada)

    2005-07-01

    This presentation described Ontario Power Generation's experience in implementing a decision support tool to enable water management plans for its operations through technology solutions. All hydroelectric producers in Ontario are required to make water management plans in order to maintain water levels and flows in their operating regions. This regulation was created in response to environmental concerns as well as to changes in the electricity market and growth of residential and cottage property near water bodies. In order to keep informed and to address compliance issues, operators and managers need situation awareness information to balance operational decisions. The online Adaptive Water Management System (AWMS) decision support tool was recently adopted by Ontario Power Generation to provide information needed to address the requirements of Water Management Plans. The AWMS provides users with information on water levels and flows; the ability to implement, modify, and manage daily instructions at the facilities; track conditions in the watershed; and, provide a status of compliance. The tool was developed by 4DM Inc. in collaboration with Ottawa St. Lawrence Plant Group for the Madawaska River Watershed Management, a model partnership between operator, regulator and Public Advisory Committee to develop a water management plan.

  16. Track measurement in the high multiplicity environment at the CBM Experiment

    International Nuclear Information System (INIS)

    Ghosh, Pradeep

    2014-01-01

    In the Compressed Baryonic Matter (CBM) Experiment at FAIR, the Silicon Tracking System (STS) will perform track reconstruction and momentum determination of the charged particles created in interactions of heavy-ion beams with nuclear targets. The STS will consist of 8 tracking layers located at distances between 30 cm and 100 cm downstream of the target inside the 1 Tm magnetic dipole field. An ultra-low material budget is required to achieve momentum resolution of the order of Δp/p = 1%. Therefore, the front-end electronics is placed outside the physics aperture. The active volume of the STS is built from 300 μm thick double-sided silicon microstrip sensors mounted onto lightweight carbon fiber support ladders. The sensors will be read out through ultra-thin micro-cables with fast self-triggering electronics at the periphery of the stations where also other infrastructure such as cooling can be placed. In this paper, the development status of the detector system, highlighting the overview of the STS layout, tracking algorithm and performance simulations are presented.

  17. Climate and atmosphere simulator for experiments on ecological systems in changing environments.

    Science.gov (United States)

    Verdier, Bruno; Jouanneau, Isabelle; Simonnet, Benoit; Rabin, Christian; Van Dooren, Tom J M; Delpierre, Nicolas; Clobert, Jean; Abbadie, Luc; Ferrière, Régis; Le Galliard, Jean-François

    2014-01-01

    Grand challenges in global change research and environmental science raise the need for replicated experiments on ecosystems subjected to controlled changes in multiple environmental factors. We designed and developed the Ecolab as a variable climate and atmosphere simulator for multifactor experimentation on natural or artificial ecosystems. The Ecolab integrates atmosphere conditioning technology optimized for accuracy and reliability. The centerpiece is a highly contained, 13-m(3) chamber to host communities of aquatic and terrestrial species and control climate (temperature, humidity, rainfall, irradiance) and atmosphere conditions (O2 and CO2 concentrations). Temperature in the atmosphere and in the water or soil column can be controlled independently of each other. All climatic and atmospheric variables can be programmed to follow dynamical trajectories and simulate gradual as well as step changes. We demonstrate the Ecolab's capacity to simulate a broad range of atmospheric and climatic conditions, their diurnal and seasonal variations, and to support the growth of a model terrestrial plant in two contrasting climate scenarios. The adaptability of the Ecolab design makes it possible to study interactions between variable climate-atmosphere factors and biotic disturbances. Developed as an open-access, multichamber platform, this equipment is available to the international scientific community for exploring interactions and feedbacks between ecological and climate systems.

  18. Adding Value to Total Joint Arthroplasty Care in an Academic Environment: The Utah Experience.

    Science.gov (United States)

    Pelt, Christopher E; Anderson, Mike B; Erickson, Jill A; Gililland, Jeremy M; Peters, Christopher L

    2018-06-01

    Adding value in a university-based academic health care system provides unique challenges when compared to other health care delivery models. Herein, we describe our experience in adding value to joint arthroplasty care at the University of Utah, where the concept of value-based health care reform has become an embraced and driving force. To improve the value, new resources were needed for care redesign, physician leadership, and engagement in alternative payment models. The changes that occurred at our institution are described. Real-time data and knowledgeable personnel working behind the scenes, while physicians provide clinical care, help move clinical pathway redesigns. Engaged physicians are essential to the successful implementation of value creation and care pathway redesign that can lead to improvements in value. An investment of money and resources toward added infrastructure and personnel is often needed to realize large-scale improvements. Alignment of providers, payers, and hospital administration, including by means of gainsharing programs, can lead to improvements. Although significant care pathway redesign efforts may realize substantial initial cost savings, savings may be asymptotic in nature, which calls into question the likely sustainability of programs that incentivize or penalize payments based on historical targets. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Rapid population growth and fragile environments: the sub-Saharan African and south Asian experience.

    Science.gov (United States)

    Caldwell, J C; Caldwell, P

    1994-02-18

    product of political mismanagement and civil disorder; 6) deforestation is as important an issue as protection of the livelihoods of forest populations. Case studies were provided for Ekiti district of Nigeria, the West and East African Savannahs, Karnataka state in South India, arid South Asia, and Nepal. The protection of the most fragile environments subject to population pressure can be managed with respect for human dignity through general economic development and external assistance.

  20. The Low-luminosity Type IIP Supernova 2016bkv with Early-phase Circumstellar Interaction

    Science.gov (United States)

    Nakaoka, Tatsuya; Kawabata, Koji S.; Maeda, Keiichi; Tanaka, Masaomi; Yamanaka, Masayuki; Moriya, Takashi J.; Tominaga, Nozomu; Morokuma, Tomoki; Takaki, Katsutoshi; Kawabata, Miho; Kawahara, Naoki; Itoh, Ryosuke; Shiki, Kensei; Mori, Hiroki; Hirochi, Jun; Abe, Taisei; Uemura, Makoto; Yoshida, Michitoshi; Akitaya, Hiroshi; Moritani, Yuki; Ueno, Issei; Urano, Takeshi; Isogai, Mizuki; Hanayama, Hidekazu; Nagayama, Takahiro

    2018-06-01

    We present optical and near-infrared observations of a low-luminosity (LL) Type IIP supernova (SN) 2016bkv from the initial rising phase to the plateau phase. Our observations show that the end of the plateau is extended to ≳140 days since the explosion, indicating that this SN takes one of the longest times to finish the plateau phase among Type IIP SNe (SNe IIP), including LL SNe IIP. The line velocities of various ions at the middle of the plateau phase are as low as 1000–1500 km s‑1, which is the lowest even among LL SNe IIP. These measurements imply that the ejecta mass in SN 2016bkv is larger than that of the well-studied LL IIP SN 2003Z. In the early phase, SN 2016bkv shows a strong bump in the light curve. In addition, the optical spectra in this bump phase exhibit a blue continuum accompanied by a narrow Hα emission line. These features indicate an interaction between the SN ejecta and the circumstellar matter (CSM) as in SNe IIn. Assuming the ejecta–CSM interaction scenario, the mass loss rate is estimated to be ∼ 1.7× {10}-2 {M}ȯ yr‑1 within a few years before the SN explosion. This is comparable to or even larger than the largest mass loss rate observed for the Galactic red supergiants (∼ {10}-3 {M}ȯ yr‑1 for VY CMa). We suggest that the progenitor star of SN 2016bkv experienced a violent mass loss just before the SN explosion.

  1. Heating the Primordial Soup: X-raying the Circumstellar Disk of T Cha

    Science.gov (United States)

    Principe, David; Huenemoerder, D.; Kastner, J. H.; Bessell, M. S.; Sacco, G.

    2014-01-01

    The classical T Tauri Star (cTTS) T Chamaeleontis (T Cha) presents a unique opportunity to probe pre-main sequence star-disk interactions and late-stage circumstellar disk evolution. T Cha is the only known example of a nearly edge-on, actively accreting star/disk system within ~110 pc, and furthermore may be orbited by a low-mass companion or massive planet that has cleared an inner hole in its disk. The star is characterized by strong variability in the optical 3 magnitudes in the V band) as well as large and variable extinction (AV in the range of 1-5). Like most cTTS, T Cha is also a luminous X-ray source. We present preliminary results of two observations (totaling 150 ks) of T Cha with Chandra’s HETGS. Our motivations are to (a) determine the intrinsic X-ray spectrum of T Cha, so as to establish whether its X-ray emission can be attributed to accretion shocks, coronal emission, or a combination; (b) investigate whether its X-ray flux exhibits modulation that may be related to the stellar rotational period 3.3 days); and (c) take advantage of the nearly-edge-on disk viewing geometry to model the spectrum of X-rays absorbed by the gaseous disk orbiting T Cha. These results will serve as much-needed input to models of magnetospheric accretion and irradiated, planet-forming disks. This research is supported via award number GO3-14022X to RIT issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS803060. Additional support is provided by National Science Foundation grant AST-1108950 to RIT.

  2. Measuring the Progenitor Masses and Dense Circumstellar Material of Type II Supernovae

    Science.gov (United States)

    Morozova, Viktoriya; Piro, Anthony L.; Valenti, Stefano

    2018-05-01

    Recent modeling of hydrogen-rich Type II supernova (SN II) light curves suggests the presence of dense circumstellar material (CSM) surrounding the exploding progenitor stars. This has important implications for the activity and structure of massive stars near the end of their lives. Since previous work focused on just a few events, here we expand to a larger sample of 20 well-observed SNe II. For each event we are able to constrain the progenitor zero-age main-sequence (ZAMS) mass, explosion energy, and the mass and radial extent of the dense CSM. We then study the distribution of each of these properties across the full sample of SNe. The inferred ZAMS masses are found to be largely consistent with a Salpeter distribution with minimum and maximum masses of 10.4 and 22.9 M ⊙, respectively. We also compare the individual ZAMS masses we measure with specific SNe II that have pre-explosion imaging to check their consistency. Our masses are generally comparable to or higher than the pre-explosion imaging masses, potentially helping ease the red supergiant problem. The explosion energies vary from (0.1–1.3) × 1051 erg, and for ∼70% of the SNe we obtain CSM masses in the range between 0.18 and 0.83 M ⊙. We see a potential correlation between the CSM mass and explosion energy, which suggests that pre-explosion activity has a strong impact on the structure of the star. This may be important to take into account in future studies of the ability of the neutrino mechanism to explode stars. We also see a possible correlation between the CSM radial extent and ZAMS mass, which could be related to the time with respect to explosion when the CSM is first generated.

  3. Circumstellar envelopes seen in radio (OH masers) and in the infrared observations (IRAS)

    International Nuclear Information System (INIS)

    David, Pedro-Correia-de-Matos

    1992-01-01

    Intermediate mass stars, namely from one to nine solar masses, eject mass into the surrounding interstellar medium at high rates (up to 1/10000 solar masses per year) in their late stages of evolution on the so called asymptotic giant branch (AGB). Indeed, the presence of a circumstellar envelope (CSE) composed of dust and gas is one of the principal features of the objects on the AGB. Because of the high opacity at visible wavelength of the CSE, most of these objects can only be observed at infrared and radio frequencies. This study was undertaken using infrared and radio data from a large sample of CSE sources. The infrared data was obtained from the infrared astronomical satellite (IRAS) data base. For a selection of IRAS objects, radio observations were made of the OH maser at 1612 and 1667 MHz at the Nancay radio telescope, France. This work consists in two parts, one is theoretical in nature, the other observational. The theoretical part is concerned with the modeling of IRAS low resolution spectra (LRS catalog) and IRAS photometry through the use of a radiative transfer code. Confrontation between models and data has yielded such results as a better definition of the grain optical properties and the behavior of the CSE as it evolves. A model of a shock wave (a possible lifting engine of the CSE) propagating in the atmosphere of Mira stars (AGB) is described. On the observational side, a large number of objects has been surveyed for the presence of OH masers at 1612 and 1667 MHz. A statistical analysis has established more clearly the evolutionary status of CSE and the OH maser characteristics. A compiling of detection rates for the occurrence of masers, average location of these masing CSEs in the Galaxy, and OH maser characteristics is reported for use in future work. (author) [fr

  4. Stripped-envelope supernova SN 2004dk is now interacting with hydrogen-rich circumstellar material

    Science.gov (United States)

    Mauerhan, Jon C.; Filippenko, Alexei V.; Zheng, WeiKang; Brink, Thomas; Graham, Melissa L.; Shivvers, Isaac; Clubb, Kelsey

    2018-05-01

    The dominant mechanism and time scales over which stripped-envelope supernovae (SNe) progenitor stars shed their hydrogen envelopes are uncertain. Observations of Type Ib and Ic SNe at late phases could reveal the optical signatures of interaction with distant circumstellar material (CSM) providing important clues on the origin of the necessary pre-SN mass loss. We report deep late-time optical spectroscopy of the Type Ib explosion SN 2004dk 4684 days (13 years) after discovery. We detect strong Hα emission with an intermediate line width of ˜400 km s-1 and luminosity ˜2.5 × 1039 erg s-1, signaling that the SN blast wave has caught up with the hydrogen-rich CSM lost by the progenitor system. The line luminosity is the highest ever reported for a SN at this late stage. Prominent emission features of He I, Fe, and Ca are also detected. The spectral characteristics are consistent with CSM energized by the forward shock, and resemble the late-time spectra of the persistently interacting Type IIn SNe 2005ip and 1988Z. We suggest that the onset of interaction with H-rich CSM was associated with a previously reported radio rebrightening at ˜1700 days. The data indicate that the mode of pre-SN mass loss was a relatively slow dense wind that persisted millennia before the SN, followed by a short-lived Wolf-Rayet phase that preceded core-collapse and created a cavity within an extended distribution of CSM. We also present new spectra of SNe 2014C, PTF11iqb, and 2009ip, all of which also exhibit continued interaction with extended CSM distributions.

  5. A Search for Phosphine in Circumstellar Envelopes: PH3 in IRC +10216 and CRL 2688?

    Science.gov (United States)

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

    2008-06-01

    We present the results of a search for the JK = 10→ 00 transition of PH3 (phosphine) at 267 GHz toward several circumstellar envelopes using the Arizona Radio Observatory 10 m Submillimeter Telescope (SMT). In the carbon-rich shells of IRC +10216 and CRL 2688, we have detected emission lines exactly at the PH3 frequency. Toward the oxygen-rich supergiant VY Canis Majoris, only an upper limit was obtained, while in the evolved carbon-rich proto-planetary nebula CRL 618, the transition is contaminated by vibrationally excited HC3N (ν7 = 4). The line shape in IRC +10216 appears to consist of two distinct components: a flat-topped profile with a width of ~28 km s-1, as is typical for this source, and a narrower feature approximately 4 km s-1 wide. The narrow component likely arises from the inner envelope (r < 8R*) where the gas has not reached the terminal expansion velocity, or it is nonthermal emission. Based on the broader component, the abundance of PH3 with respect to H2 is estimated to be 5 × 10-8 in a region with a radius of r < 150R*. If the narrower component is thermal, it implies a phosphine abundance of ~5 × 10-7 close to the stellar photosphere (r < 8R*). In CRL 2688, the PH3 abundance is less constrained, with plausible values ranging from 3 × 10-8 to 4 × 10-7, assuming a spherical distribution. Phosphine appears to be present in large concentrations in the inner envelope of C-rich AGB stars, and thus may function as a parent molecule for other phosphorus species.

  6. FIRST DETECTION OF NEAR-INFRARED LINE EMISSION FROM ORGANICS IN YOUNG CIRCUMSTELLAR DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Mandell, Avi M.; Mumma, Michael J.; Villanueva, Geronimo [Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Bast, Jeanette; Van Dishoeck, Ewine F. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Blake, Geoffrey A. [California Institute of Technology, Division of Geological and Planetary Sciences, MS 150-21, Pasadena, CA 91125 (United States); Salyk, Colette, E-mail: Avi.Mandell@nasa.gov [Department of Astronomy, University of Texas, Austin, TX 78712 (United States)

    2012-03-10

    We present an analysis of high-resolution spectroscopy of several bright T Tauri stars using the CRIRES spectrograph on the Very Large Telescope and NIRSPEC spectrograph on the Keck Telescope, revealing the first detections of emission from HCN and C{sub 2}H{sub 2} in circumstellar disks at near-infrared wavelengths. Using advanced data reduction techniques, we achieve a dynamic range with respect to the disk continuum of {approx}500 at 3 {mu}m, revealing multiple emission features of H{sub 2}O, OH, HCN, and C{sub 2}H{sub 2}. We also present stringent upper limits for two other molecules thought to be abundant in the inner disk, CH{sub 4} and NH{sub 3}. Line profiles for the different detected molecules are broad but centrally peaked in most cases, even for disks with previously determined inclinations of greater than 20 Degree-Sign , suggesting that the emission has both a Keplerian and non-Keplerian component as observed previously for CO emission. We apply two different modeling strategies to constrain the molecular abundances and temperatures: we use a simplified single-temperature local thermal equilibrium (LTE) slab model with a Gaussian line profile to make line identifications and determine a best-fit temperature and initial abundance ratios, and we compare these values with constraints derived from a detailed disk radiative transfer model assuming LTE excitation but utilizing a realistic temperature and density structure. Abundance ratios from both sets of models are consistent with each other and consistent with expected values from theoretical chemical models, and analysis of the line shapes suggests that the molecular emission originates from within a narrow region in the inner disk (R < 1 AU).

  7. The First 40 Million Years of Circumstellar Disk Evolution: The Signature of Terrestrial Planet Formation

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Huan Y. A.; Rieke, George H.; Su, Kate Y. L.; Gáspár, András, E-mail: hyameng@lpl.arizona.edu [Steward Observatory, Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

    2017-02-10

    We characterize the first 40 Myr of evolution of circumstellar disks through a unified study of the infrared properties of members of young clusters and associations with ages from 2 Myr up to ∼40 Myr: NGC 1333, NGC 1960, NGC 2232, NGC 2244, NGC 2362, NGC 2547, IC 348, IC 2395, IC 4665, Chamaeleon I, Orion OB1a and OB1b, Taurus, the β Pictoris Moving Group, ρ Ophiuchi, and the associations of Argus, Carina, Columba, Scorpius–Centaurus, and Tucana–Horologium. Our work features: (1) a filtering technique to flag noisy backgrounds; (2) a method based on the probability distribution of deflections, P ( D ), to obtain statistically valid photometry for faint sources; and (3) use of the evolutionary trend of transitional disks to constrain the overall behavior of bright disks. We find that the fraction of disks three or more times brighter than the stellar photospheres at 24 μ m decays relatively slowly initially and then much more rapidly by ∼10 Myr. However, there is a continuing component until ∼35 Myr, probably due primarily to massive clouds of debris generated in giant impacts during the oligarchic/chaotic growth phases of terrestrial planets. If the contribution from primordial disks is excluded, the evolution of the incidence of these oligarchic/chaotic debris disks can be described empirically by a log-normal function with the peak at 12–20 Myr, including ∼13% of the original population, and with a post-peak mean duration of 10–20 Myr.

  8. The First 40 Million Years of Circumstellar Disk Evolution: The Signature of Terrestrial Planet Formation

    International Nuclear Information System (INIS)

    Meng, Huan Y. A.; Rieke, George H.; Su, Kate Y. L.; Gáspár, András

    2017-01-01

    We characterize the first 40 Myr of evolution of circumstellar disks through a unified study of the infrared properties of members of young clusters and associations with ages from 2 Myr up to ∼40 Myr: NGC 1333, NGC 1960, NGC 2232, NGC 2244, NGC 2362, NGC 2547, IC 348, IC 2395, IC 4665, Chamaeleon I, Orion OB1a and OB1b, Taurus, the β Pictoris Moving Group, ρ Ophiuchi, and the associations of Argus, Carina, Columba, Scorpius–Centaurus, and Tucana–Horologium. Our work features: (1) a filtering technique to flag noisy backgrounds; (2) a method based on the probability distribution of deflections, P ( D ), to obtain statistically valid photometry for faint sources; and (3) use of the evolutionary trend of transitional disks to constrain the overall behavior of bright disks. We find that the fraction of disks three or more times brighter than the stellar photospheres at 24 μ m decays relatively slowly initially and then much more rapidly by ∼10 Myr. However, there is a continuing component until ∼35 Myr, probably due primarily to massive clouds of debris generated in giant impacts during the oligarchic/chaotic growth phases of terrestrial planets. If the contribution from primordial disks is excluded, the evolution of the incidence of these oligarchic/chaotic debris disks can be described empirically by a log-normal function with the peak at 12–20 Myr, including ∼13% of the original population, and with a post-peak mean duration of 10–20 Myr.

  9. The First 40 Million Years of Circumstellar Disk Evolution: The Signature of Terrestrial Planet Formation

    Science.gov (United States)

    Meng, Huan Y. A.; Rieke, George H.; Su, Kate Y. L.; Gáspár, András

    2017-02-01

    We characterize the first 40 Myr of evolution of circumstellar disks through a unified study of the infrared properties of members of young clusters and associations with ages from 2 Myr up to ˜40 Myr: NGC 1333, NGC 1960, NGC 2232, NGC 2244, NGC 2362, NGC 2547, IC 348, IC 2395, IC 4665, Chamaeleon I, Orion OB1a and OB1b, Taurus, the β Pictoris Moving Group, ρ Ophiuchi, and the associations of Argus, Carina, Columba, Scorpius-Centaurus, and Tucana-Horologium. Our work features: (1) a filtering technique to flag noisy backgrounds; (2) a method based on the probability distribution of deflections, P(D), to obtain statistically valid photometry for faint sources; and (3) use of the evolutionary trend of transitional disks to constrain the overall behavior of bright disks. We find that the fraction of disks three or more times brighter than the stellar photospheres at 24 μm decays relatively slowly initially and then much more rapidly by ˜10 Myr. However, there is a continuing component until ˜35 Myr, probably due primarily to massive clouds of debris generated in giant impacts during the oligarchic/chaotic growth phases of terrestrial planets. If the contribution from primordial disks is excluded, the evolution of the incidence of these oligarchic/chaotic debris disks can be described empirically by a log-normal function with the peak at 12-20 Myr, including ˜13% of the original population, and with a post-peak mean duration of 10-20 Myr.

  10. The Circumstellar Disk and Asymmetric Outflow of the EX Lup Outburst System

    Science.gov (United States)

    Hales, A. S.; Pérez, S.; Saito, M.; Pinte, C.; Knee, L. B. G.; de Gregorio-Monsalvo, I.; Dent, B.; López, C.; Plunkett, A.; Cortés, P.; Corder, S.; Cieza, L.

    2018-06-01

    We present Atacama Large Millimeter/submillimeter Array (ALMA) observations at 0.″3 resolution of EX Lup, the prototype of the EXor class of outbursting pre-main-sequence stars. The circumstellar disk of EX Lup is resolved for the first time in 1.3 mm continuum emission and in the J = 2–1 spectral line of three isotopologues of CO. At the spatial resolution and sensitivity achieved, the compact dust continuum disk shows no indications of clumps, fragments, or asymmetries above the 5σ level. Radiative transfer modeling constrains the characteristic radius of the dust disk to 23 au and the total dust mass to 1.0 × 10‑4 M ⊙ (33 M ⊕), similar to other EXor sources. The 13CO and C18O line emissions trace the disk rotation and are used to constrain the disk geometry, kinematics, and a total gas disk mass of 5.1 × 10‑4 M ⊙. The 12CO emission extends out to a radius of 200 au and is asymmetric, with one side deviating from Keplerian rotation. We detect blueshifted, 12CO arc-like emission located 0.″8 to the northwest and spatially disconnected from the disk emission. We interpret this extended structure as the brightened walls of a cavity excavated by an outflow, which are more commonly seen in FUor sources. Such outflows have also been seen in the borderline FU/EXor object V1647 Ori, but not toward EXor objects. Our detection provides evidence that the outflow phenomenon persists into the EXor phase, suggesting that FUor and EXor objects are a continuous population in which outflow activity declines with age, with transitional objects such as EX Lup and V1647 Ori.

  11. A deep Spitzer survey of circumstellar disks in the young double cluster, h and χ Persei

    Energy Technology Data Exchange (ETDEWEB)

    Cloutier, Ryan; Currie, Thayne; Jayawardhana, Ray [University of Toronto, 50 St. George Street, Toronto, ON, M5S 2J7 (Canada); Rieke, George H. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Kenyon, Scott J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02140 (United States); Balog, Zoltan, E-mail: cloutier@cita.utoronto.ca, E-mail: currie@astro.utoronto.ca, E-mail: grieke@as.arizona.edu, E-mail: skenyon@cfa.harvard.edu [Max Planck Institute for Astrophysics, Königstuhl 17, D-69117 Heidelberg (Germany)

    2014-12-01

    We analyze very deep Infrared Array Camera and Multiband Imaging Photometer for Spitzer (MIPS) photometry of ∼12, 500 members of the 14 Myr old Double Cluster, h and χ Persei, building upon our earlier, shallower Spitzer Cycle 1 studies. Numerous likely members show infrared (IR) excesses at 8 μm and 24 μm, indicative of circumstellar dust. The frequency of stars with 8 μm excess is at least 2% for our entire sample, slightly lower (higher) for B/A stars (later type, lower mass stars). Optical spectroscopy also identifies gas in about 2% of systems, but with no clear trend between the presence of dust and gas. Spectral energy distribution modeling of 18 sources with detections at optical wavelengths through MIPS 24 μm reveals a diverse set of disk evolutionary states, including a high fraction of transitional disks, though similar data for all disk-bearing members would provide constraints. Using Monte Carlo simulations, we combine our results with those for other young clusters to study the global evolution of dust/gas disks. For nominal cluster ages, the e-folding times (τ{sub 0}) for the frequency of warm dust and gas are 2.75 Myr and 1.75 Myr, respectively. Assuming a revised set of ages for some clusters, these timescales increase to 5.75 and 3.75 Myr, respectively, implying a significantly longer typical protoplanetary disk lifetime than previously thought. In both cases, the transitional disk duration, averaged over multiple evolutionary pathways, is ≈1 Myr. Finally, 24 μm excess frequencies for 4-6 M {sub ☉} stars appear lower than for 1-2.5 M {sub ☉} stars in other 10-30 Myr old clusters.

  12. A new Wolf-Rayet star and its circumstellar nebula in Aquila

    Science.gov (United States)

    Gvaramadze, V. V.; Kniazev, A. Y.; Hamann, W.-R.; Berdnikov, L. N.; Fabrika, S.; Valeev, A. F.

    2010-04-01

    We report the discovery of a new Wolf-Rayet star in Aquila via detection of its circumstellar nebula (reminiscent of ring nebulae associated with late WN stars) using the Spitzer Space Telescope archival data. Our spectroscopic follow-up of the central point source associated with the nebula showed that it is a WN7h star (we named it WR121b). We analysed the spectrum of WR121b by using the Potsdam Wolf-Rayet model atmospheres, obtaining a stellar temperature of ~=50kK. The stellar wind composition is dominated by helium with ~20 per cent of hydrogen. The stellar spectrum is highly reddened [E(B - V) = 2.85mag]. Adopting an absolute magnitude of Mv = -5.7, the star has a luminosity of logL/Lsolar = 5.75 and a mass-loss rate of 10-4.7Msolaryr-1, and resides at a distance of 6.3kpc. We searched for a possible parent cluster of WR121b and found that this star is located at ~=1° from the young star cluster embedded in the giant HII region W43 (containing a WN7+a/OB? star - WR121a). We also discovered a bow shock around the O9.5III star ALS9956, located at from the cluster. We discuss the possibility that WR121b and ALS9956 are runaway stars ejected from the cluster in W43. Based on observations collected at the German-Spanish Astronomical Center, Calar Alto, jointly operated by the Max-Planck-Institut für Astronomie Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC). E-mail: vgvaram@mx.iki.rssi.ru (VVG); akniazev@saao.ac.za (AYK); wrh@astro.physik.uni-potsdam.de (WRH); berdnik@sai.msu.ru (LNB); fabrika@sao.ru (SF); azamat@sao.ru (AFV)

  13. Models of the circumstellar medium of evolving, massive runaway stars moving through the Galactic plane

    Science.gov (United States)

    Meyer, D. M.-A.; Mackey, J.; Langer, N.; Gvaramadze, V. V.; Mignone, A.; Izzard, R. G.; Kaper, L.

    2014-11-01

    At least 5 per cent of the massive stars are moving supersonically through the interstellar medium (ISM) and are expected to produce a stellar wind bow shock. We explore how the mass-loss and space velocity of massive runaway stars affect the morphology of their bow shocks. We run two-dimensional axisymmetric hydrodynamical simulations following the evolution of the circumstellar medium of these stars in the Galactic plane from the main sequence to the red supergiant phase. We find that thermal conduction is an important process governing the shape, size and structure of the bow shocks around hot stars, and that they have an optical luminosity mainly produced by forbidden lines, e.g. [O III]. The Hα emission of the bow shocks around hot stars originates from near their contact discontinuity. The Hα emission of bow shocks around cool stars originates from their forward shock, and is too faint to be observed for the bow shocks that we simulate. The emission of optically thin radiation mainly comes from the shocked ISM material. All bow shock models are brighter in the infrared, i.e. the infrared is the most appropriate waveband to search for bow shocks. Our study suggests that the infrared emission comes from near the contact discontinuity for bow shocks of hot stars and from the inner region of shocked wind for bow shocks around cool stars. We predict that, in the Galactic plane, the brightest, i.e. the most easily detectable bow shocks are produced by high-mass stars moving with small space velocities.

  14. Optical spectroscopy of the blue supergiant Sk-69° 279 and its circumstellar shell with SALT

    Science.gov (United States)

    Gvaramadze, V. V.; Kniazev, A. Y.; Maryeva, O. V.; Berdnikov, L. N.

    2018-02-01

    We report the results of optical spectroscopy of the blue supergiant Sk-69° 279 and its circular shell in the Large Magellanic Cloud (LMC) with the Southern African Large Telescope (SALT). We classify Sk-69° 279 as an O9.2 Iaf star and analyse its spectrum by using the stellar atmosphere code CMFGEN, obtaining a stellar temperature of ≈30 kK, a luminosity of log (L*/ L⊙) = 5.54, a mass-loss rate of log (\\dot{M}/ M_{⊙} yr^{-1}) = -5.26, and a wind velocity of 800km s-1. We found also that Sk-69° 279 possesses an extended atmosphere with an effective temperature of ≈24 kK and that its surface helium and nitrogen abundances are enhanced, respectively, by factors of ≈2 and 20-30. This suggests that either Sk-69° 279 was initially a (single) fast-rotating ( ≳ 400 km s- 1) star, which only recently evolved off the main sequence, or that it is a product of close binary evolution. The long-slit spectroscopy of the shell around Sk-69° 279 revealed that its nitrogen abundance is enhanced by the same factor as the stellar atmosphere, which implies that the shell is composed mostly of the CNO processed material lost by the star. Our findings support previous propositions that some massive stars can produce compact circumstellar shells and, presumably, appear as luminous blue variables while they are still on the main sequence or have only recently left it.

  15. Experiences of using the Theoretical Domains Framework across diverse clinical environments: a qualitative study

    Directory of Open Access Journals (Sweden)

    Phillips CJ

    2015-03-01

    Framework (TDF is an integrative framework developed from a synthesis of psychological theories as a vehicle to help apply theoretical approaches to interventions aimed at behavior change. Purpose: This study explores experiences of TDF use by professionals from multiple disciplines across diverse clinical settings. Methods: Mixed methods were used to examine experiences, attitudes, and perspectives of health professionals in using the TDF in health care implementation projects. Individual interviews were conducted with ten health care professionals from six disciplines who used the TDF in implementation projects. Deductive content and thematic analysis were used. Results: Three main themes and associated subthemes were identified including: 1 reasons for use of the TDF (increased confidence, broader perspective, and theoretical underpinnings; 2 challenges using the TDF (time and resources, operationalization of the TDF and; 3 future use of the TDF. Conclusion: The TDF provided a useful, flexible framework for a diverse group of health professionals working across different clinical settings for the assessment of barriers and targeting resources to influence behavior change for implementation projects. The development of practical tools and training or support is likely to aid the utility of TDF. Keywords: barriers and enablers, behavioral change, evidence-based practice, implementation, health care, Theoretical Domains Framework

  16. Field experiment determinations of distribution coefficients of actinide elements in alkaline lake environments

    International Nuclear Information System (INIS)

    Simpson, H.J.; Trier, R.M.; Li, Y.H.; Anderson, R.F.

    1984-01-01

    Radionuclide concentrations of a number of elements (Am, Pu, U, Pa, Th, Ac, Ra, Po, Pb, Cs, and Sr) have been measured in the water and sediments of a group of alkaline lakes in the western USA. These data demonstrate greatly enhanced soluble phase concentrations of elements with oxidation states of III, IV, V, and VI as the result of carbonate complexing. Dissolved concentrations of isotopes of U, Pa, and Th in a lake with pH = 10 and a total inorganic carbon concentration of 4 x 10 -1 moles/1 were greater than those in sea water (pH = 8, ΣCO 2 = 2 x 10 -3 moles/1) by order of magnitude for 233 U, 238 U (--10 2 ), 231 Pa, 228 Th, 230 Th (--10 3 ) and 22 Th (--10 5 ). Concentrations of fallout /sup 239,240/Pu in the more alkaline lakes were equivalent to effective distribution coefficients of --10 3 , about a factor of 10 2 lower than in most other natural lakes, rivers, estuaries and coastal marine waters. Measurements of radionuclides in natural systems are essential for assessment of the likely fate of radionuclides which may be released from high level waste repositories to ground water. Laboratory-scale experiments using tracer additions of radionuclides to mixtures of water and sediment yielded distribution coefficients which were significantly different from those derived from field measurements (10 1 -10 2 lower for Po and Pu). Order of magnitude calculations from thermodynamic data of expected maximum U and Th concentrations, limited by pure phase solubilities, suggest that carbonate complexing can enhance solubility by many orders of magnitude in natural waters, even at relatively low carbonate ion concentrations

  17. Profile control simulations and experiments on TCV: a controller test environment and results using a model-based predictive controller

    Science.gov (United States)

    Maljaars, E.; Felici, F.; Blanken, T. C.; Galperti, C.; Sauter, O.; de Baar, M. R.; Carpanese, F.; Goodman, T. P.; Kim, D.; Kim, S. H.; Kong, M.; Mavkov, B.; Merle, A.; Moret, J. M.; Nouailletas, R.; Scheffer, M.; Teplukhina, A. A.; Vu, N. M. T.; The EUROfusion MST1-team; The TCV-team

    2017-12-01

    The successful performance of a model predictive profile controller is demonstrated in simulations and experiments on the TCV tokamak, employing a profile controller test environment. Stable high-performance tokamak operation in hybrid and advanced plasma scenarios requires control over the safety factor profile (q-profile) and kinetic plasma parameters such as the plasma beta. This demands to establish reliable profile control routines in presently operational tokamaks. We present a model predictive profile controller that controls the q-profile and plasma beta using power requests to two clusters of gyrotrons and the plasma current request. The performance of the controller is analyzed in both simulation and TCV L-mode discharges where successful tracking of the estimated inverse q-profile as well as plasma beta is demonstrated under uncertain plasma conditions and the presence of disturbances. The controller exploits the knowledge of the time-varying actuator limits in the actuator input calculation itself such that fast transitions between targets are achieved without overshoot. A software environment is employed to prepare and test this and three other profile controllers in parallel in simulations and experiments on TCV. This set of tools includes the rapid plasma transport simulator RAPTOR and various algorithms to reconstruct the plasma equilibrium and plasma profiles by merging the available measurements with model-based predictions. In this work the estimated q-profile is merely based on RAPTOR model predictions due to the absence of internal current density measurements in TCV. These results encourage to further exploit model predictive profile control in experiments on TCV and other (future) tokamaks.

  18. Nursing home nurses' experiences of resident transfers to the emergency department: no empathy for our work environment difficulties.

    Science.gov (United States)

    Tsai, Hsiu-Hsin; Tsai, Yun-Fang; Huang, Hsiu-Li

    2016-03-01

    To explore the experiences of nursing home nurses when they transfer residents from nursing homes to the emergency department in Taiwan. The transfer of residents between nursing homes and emergency departments challenges continuity of care. Understanding nursing home nurses' experiences during these transfers may help to improve residents' continuity of care. However, few empirical data are available on these nurses' transfer experiences worldwide, and none could be found in Asian countries. Qualitative descriptive study. Data were collected from August 2012-June 2013 in audiotaped, individual, in-depth interviews with 25 nurses at five nursing homes in Taiwan. Interview transcripts were analysed by constant comparative analysis. Analysis of interview transcripts revealed that the core theme of nursing home nurses' transfer experience was discontinuity in nursing home to emergency department transitions. This core theme comprised three themes: discontinuity in family involvement, discontinuity in medical resources and expectations, and discontinuity in nurses' professional role. Nursing home nurses need a working environment that is better connected to residents' family members and more immediate and/or easier access to acute care for residents. Communication between nurses and residents' family could be improved by using text messages or social media by mobile phones, which are widely used in Taiwan and worldwide. To improve access to acute care, we suggest developing a real-time telehealth transfer system tailored to the medical culture and policies of each country. This system should facilitate communication among nursing home staff, family members and hospital staff. Our findings on nurses' experiences during transfer of nursing home residents to the emergency department can be used to design more effective transfer policies such as telemedicine systems in Taiwan and other Asian countries or in those with large populations of Chinese immigrants. © 2016 John

  19. Making the informal formal: An examination of why and how teachers and students leverage experiences in informal learning environments

    Science.gov (United States)

    Schneider, Barbara P.

    This study was an effort to understand the impact of informal learning environments (museums, aquaria, nature centers, and outdoor education programs) on school groups by developing a picture of why and how teachers and their students leverage experiences in these settings. This work relied on the self-reported visions for science education of formal and informal teachers as a means of creating a portrait or profile of the teacher visitor thus providing a new way to assess the quality of informal visits based on vision elements. Multi-level, year long case studies at six school sites and their partnering informal centers that included multiple interviews, observations (250 hours) of both school based and field trip activities, as well as focus group interviews with students two months past their field trip experience comprised the bulk of data collection activities. In addition to this more intensive work with case study teachers data was gathered from a broader group of participants through surveys (n = 396) and one-time classroom teacher interviews (n = 36) in an effort to validate or confirm case study findings. I discovered that central to informal and formal teachers' visions was a view of education as empowerment. I explored such goals as empowering students to conceive of themselves and their worlds differently, empowering students by sharing responsibility for what and how they learn, and empowering students by creating environments where everyone can contribute meaningfully. Much of what classroom teachers did to leverage the informal experience in supporting their visions of education related to these goals. For example teachers used shared experiences in informal settings as a way for their students to gain better access to and understanding of the classroom curriculum thereby increasing student participation and allowing more students to be successful. They also changed their approach to content by basing the classroom curriculum on students' interests

  20. Undergraduate nursing students' experience related to their clinical learning environment and factors affecting to their clinical learning process.

    Science.gov (United States)

    Arkan, Burcu; Ordin, Yaprak; Yılmaz, Dilek

    2018-03-01

    Clinical education is an essential part of nursing education. The purpose of this study was to explore nurse students' experiences related to cinical learning environments, factors effecting to clinical learning process. Descriptive qualitative design was used in this study, and data were collected from 2nd class nursing student (n = 14). The study took the form of in-depth interviews between August-October 2015. The qualitative interviews were analyzed by using simple content analysis. Data were analyzed manually. Experiences nurse students are described five themes. The themes of the study are (1) effecting persons to clinical learning, (2) educational atmosphere, (3) students' personal charactering, (4) the impact of education in school, and (5) students' perceptions related to clinical learning. Participants stated that they experienced many difficulties during clinical learning process. All students importantly stated that nurse teacher is very effecting to clinical learning. This study contributes to the literature by providing data on beginner nursing student' experiences about clinical learning process. The data of this present study show to Turkish nursing student is affecting mostly from persons in clinical learning. The data of this present study will guide nurse teacher when they plan to interventions to be performed to support student during clinical learning process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. CRYSTALLIZATION EXPERIMENTS ON AMORPHOUS MAGNESIUM SILICATE. II. EFFECT OF STACKING FAULTS ON INFRARED SPECTRA OF ENSTATITE

    International Nuclear Information System (INIS)

    Murata, K.; Chihara, H.; Koike, C.; Takakura, T.; Imai, Y.; Tsuchiyama, A.; Noguchi, T.

    2009-01-01

    We carried out experiments of low-temperature infrared spectroscopy and transmission electron microscopy of enstatite (MgSiO 3 ) synthesized by heating of amorphous magnesium silicate. There is a discrepancy between the infrared feature of enstatite obtained in this experiment and that of fine powdered single crystals. This reflects stacking disorder of enstatite. We show that circumstellar dust emission of enstatite is similar to the infrared feature measured in this experiment. This result strongly suggests that circumstellar enstatite has abundant stacking faults and is different from the single crystal.

  2. FIRST L-BAND INTERFEROMETRIC OBSERVATIONS OF A YOUNG STELLAR OBJECT: PROBING THE CIRCUMSTELLAR ENVIRONMENT OF MWC 419

    International Nuclear Information System (INIS)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    2009-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, Michaela; Nickeler, Dieter H. [Astronomický ústav, Akademie věd České republiky, v.v.i., Fričova 298, 251 65 Ondřejov (Czech Republic); Liimets, Tiina [Tartu Observatory, 61602 Tõravere, Tartumaa (Estonia); Cappa, Cristina E.; Duronea, Nicolas U. [Instituto Argentino de Radioastronomía, CONICET, CCT-La Plata, C.C.5., 1894, Villa Elisa (Argentina); Cidale, Lydia S.; Arias, Maria L. [Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900, La Plata (Argentina); Gunawan, Diah S.; Maravelias, Grigoris; Curé, Michel [Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, Casilla 5030, Valparaíso (Chile); Oksala, Mary E. [California Lutheran University, Department of Physics, Thousand Oaks, CA 91360 (United States); Fernandes, Marcelo Borges [Observatório Nacional, Rua General José Cristino 77, 20921-400 São Cristovão, Rio de Janeiro (Brazil); Santander-García, Miguel, E-mail: michaela.kraus@asu.cas.cz [Observatorio Astronómico Nacional (IGN), C/Alfonso XII 3, E-28014, Madrid (Spain)

    2017-11-01

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

  5. CIRCUMSTELLAR ENVIRONMENT AND EFFECTIVE TEMPERATURE OF THE YOUNG SUBSTELLAR ECLIPSING BINARY 2MASS J05352184-0546085

    International Nuclear Information System (INIS)

    Mohanty, Subhanjoy; Stassun, Keivan G.; Mathieu, Robert D.

    2009-01-01

    We present new Spitzer IRAC/PU/MIPS photometry from 3.6 to 24 μm, and new Gemini GMOS photometry at 0.48 μm, of the young brown dwarf eclipsing binary 2MASS J05352184-0546085, located in the Orion Nebula Cluster. No excess disk emission is detected. The measured fluxes at λ ≤ 8 μm are within 1σ (∼ -10 M sun ) if it extends in to within ∼0.1 AU of the binary (the approximate tidal truncation radius), or it must be optically thick with a large inner hole, >0.6-10 AU in radius depending on degree of flaring. The consequence in all cases is that disk accretion is likely to be negligible or absent. This supports the recent proposal that the strong Hα emission in the primary (more massive) brown dwarf results from chromospheric activity, and thereby bolsters the hypothesis that the surprising T eff inversion observed between the components is due to strong magnetic fields on the primary. Our data also set constraints on the T eff of the components independent of spectral type, and thereby on models of the aforementioned magnetic field effects. We discuss the consequences for the derived fundamental properties of young brown dwarfs and very low mass stars in general. Specifically, if very active isolated young brown dwarfs and very low mass stars suffer the same activity/field related effects as the 2M0535-05 primary, the low-mass stellar/substellar initial mass function currently derived from standard evolutionary tracks may be substantially in error.

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

    Science.gov (United States)

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

    2017-11-01

    The Galactic object MWC 137 has been suggested to belong to the group of B[e] supergiants. However, with its large-scale optical bipolar ring nebula and high-velocity jet and knots, it is a rather atypical representative of this class. We performed multiwavelength observations spreading from the optical to the radio regimes. Based on optical imaging and long-slit spectroscopic data, we found that the northern parts of the large-scale nebula are predominantly blueshifted, while the southern regions appear mostly redshifted. We developed a geometrical model consisting of two double cones. Although various observational features can be approximated with such a scenario, the observed velocity pattern is more complex. Using near-infrared integral-field unit spectroscopy, we studied the hot molecular gas in the vicinity of the star. The emission from the hot CO gas arises in a small-scale disk revolving around the star on Keplerian orbits. Although the disk itself cannot be spatially resolved, its emission is reflected by the dust arranged in arc-like structures and the clumps surrounding MWC 137 on small scales. In the radio regime, we mapped the cold molecular gas in the outskirts of the optical nebula. We found that large amounts of cool molecular gas and warm dust embrace the optical nebula in the east, south, and west. No cold gas or dust was detected in the north and northwestern regions. Despite the new insights into the nebula kinematics gained from our studies, the real formation scenario of the large-scale nebula remains an open issue. Based on observations collected with (1) the ESO VLT Paranal Observatory under programs 094.D-0637(B) and 097.D-0033(A), (2) the MPG 2.2 m telescope at La Silla Observatory, Chile, under programs 096.A-9030(A) and 096.A-9039(A), (3) the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the 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), under program GN-2013B-Q-11, (4) the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias, (5) the APEX telescope under the program CHILE-9711B-2016. APEX is a collaboration between the Max-Planck-Institut für Radioastronomie, the European Southern Observatory, and the Onsala Observatory, and (6) the Perek 2 m telescope at Ondřejov Observatory, Czech Republic.

  7. ALMA observations of anisotropic dust mass loss in the inner circumstellar environment of the red supergiant VY Canis Majoris

    NARCIS (Netherlands)

    O'Gorman, E.; Vlemmings, W.; Richards, A.M.S.; Baudry, A.; De Beck, E.; Decin, L.; Harper, G.M.; Humphreys, E.M.; Kervella, P.; Khouri, T.; Muller, S.

    2015-01-01

    The processes leading to dust formation and the subsequent role it plays in driving mass loss in cool evolved stars is an area of intense study. Here we present high resolution ALMA Science Verification data of the continuum emission around the highly evolved oxygen-rich red supergiant VY CMa. These

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

    Czech Academy of Sciences Publication Activity Database

    Kraus, Michaela; Liimets, T.; Cappa, C.E.; Cidale, L.S.; Nickeler, Dieter Horst; Duronea, N.; Arias, M.L.; Gunawan, D.S.; Oksala, M.E.; Borges Fernandes, M.; Maravelias, G.; Curé, M.; Santander-Garcia, M.

    2017-01-01

    Roč. 154, č. 5 (2017), 186/1-186/16 ISSN 0004-6256 R&D Projects: GA ČR(CZ) GA17-02337S; GA ČR(CZ) GA16-05011S; GA MŠk LG14013 Institutional support: RVO:67985815 Keywords : emission-line stars * stellar populations * hii-regions Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 2.609, year: 2016

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

    International Nuclear Information System (INIS)

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

    2017-01-01

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

  10. The Galactic unclassified B[e] star HD50138 II. Interferometric constraints on the close circumstellar environment

    Czech Academy of Sciences Publication Activity Database

    Borges Fernandes, M.; Meilland, A.; Bendjoya, P.; de Souza, A.D.; Niccolini, G.; Chesneau, O.; Millour, F.; Spang, A.; Stee, P.; Kraus, Michaela

    2011-01-01

    Roč. 258, April (2011), A20/1-A20/9 ISSN 0004-6361 R&D Projects: GA AV ČR KJB300030701 Institutional research plan: CEZ:AV0Z10030501 Keywords : stars * winds * outflows Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.587, year: 2011

  11. Early experience of a novel-environment in isolation primes a fearful phenotype characterized by persistent amygdala activation.

    Science.gov (United States)

    Daskalakis, Nikolaos P; Diamantopoulou, Anastasia; Claessens, Sanne E F; Remmers, Elisa; Tjälve, Marika; Oitzl, Melly S; Champagne, Danielle L; de Kloet, E Ronald

    2014-01-01

    Prolonged maternal separation (MS) activates the neonate's hypothalamus-pituitary-adrenal axis causing elevated basal and stress-induced corticosterone levels that may initiate amygdala-dependent fear learning. Here we test the hypothesis that the adult fearful phenotype is programmed by the pup's stressful experience during prolonged MS rather than by prolonged maternal absence per se. For this purpose, Wistar rat pups were exposed, on postnatal-day (pnd) 3, to: (i) repeated-MS in home-environment (HOME-SEP), 8h-MS daily for three days with the pups remaining together in the home-cage; (ii) repeated-MS in a novel-environment (NOVEL-SEP), with the same separation procedure, but now the pups were individually housed in a novel-environment during the 8h dam's absence; (iii) repeated handling, which consisted of daily brief (15 min instead of 8h) MS in the home-altogether or in a novel-environment individually (HOME-HAN and NOVEL-HAN, respectively); (iv) no-separation/no-handling (NON-SEP/NON-HAN) control condition, in which pups were left undisturbed in their home-cage. Compared to HOME-SEP rats, the NOVEL-SEP rats showed one day after the last MS enhanced stress-induced amygdala c-Fos expression and ACTH-release, despite of reduced adrenal corticosterone secretion. The higher amygdala c-Fos expression, ACTH-release and reduced corticosterone output observed postnatally, persisted into adulthood of the NOVEL-SEP animals. Behaviorally, NOVEL-SEP juvenile rats displayed deficits in social play, had intact spatial memory in the peri-pubertal period and showed more contextual fear memory compared to HOME-SEP in adulthood. Finally, NOVEL-HAN, compared to HOME-HAN, displayed increased stress-induced corticosterone output, no deficits in social play and reduced contextual fear. In conclusion, programming of an adult fearful phenotype linked to amygdala priming develops if pups are repeatedly isolated from peers in a novel-environment, while away from the dam for a prolonged

  12. The Lack of Chemical Equilibrium does not Preclude the Use of the Classical Nucleation Theory in Circumstellar Outflows

    Science.gov (United States)

    Paquette, John A.; Nuth, Joseph A., III

    2011-01-01

    Classical nucleation theory has been used in models of dust nucleation in circumstellar outflows around oxygen-rich asymptotic giant branch stars. One objection to the application of classical nucleation theory (CNT) to astrophysical systems of this sort is that an equilibrium distribution of clusters (assumed by CNT) is unlikely to exist in such conditions due to a low collision rate of condensable species. A model of silicate grain nucleation and growth was modified to evaluate the effect of a nucleation flux orders of magnitUde below the equilibrium value. The results show that a lack of chemical equilibrium has only a small effect on the ultimate grain distribution.

  13. THE REINCARNATION OF INTERSTELLAR DUST: THE IMPORTANCE OF ORGANIC REFRACTORY MATERIAL IN INFRARED SPECTRA OF COMETARY COMAE AND CIRCUMSTELLAR DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Hiroshi, E-mail: hiroshi_kimura@cps-jp.org [Graduate School of Science, Kobe University, c/o CPS (Center for Planetary Science), Chuo-ku Minatojima Minamimachi 7-1-48, Kobe 650-0047 (Japan)

    2013-09-20

    We consider the reincarnation of interstellar dust to be reborn in protoplanetary disks as aggregates consisting of submicron-sized grains with a crystalline or amorphous silicate core and an organic-rich carbonaceous mantle. We find that infrared spectra of reincarnated interstellar dust reproduce emission peaks at correct wavelengths where the peaks were observed in cometary comae, debris disks, and protoplanetary disks if the volume fraction of organic refractory meets the constraints on elemental abundances. We discuss what we can learn from the infrared spectra of reincarnated interstellar dust in cometary comae and circumstellar disks.

  14. The Reincarnation of Interstellar Dust: The Importance of Organic Refractory Material in Infrared Spectra of Cometary Comae and Circumstellar Disks

    Science.gov (United States)

    Kimura, Hiroshi

    2013-09-01

    We consider the reincarnation of interstellar dust to be reborn in protoplanetary disks as aggregates consisting of submicron-sized grains with a crystalline or amorphous silicate core and an organic-rich carbonaceous mantle. We find that infrared spectra of reincarnated interstellar dust reproduce emission peaks at correct wavelengths where the peaks were observed in cometary comae, debris disks, and protoplanetary disks if the volume fraction of organic refractory meets the constraints on elemental abundances. We discuss what we can learn from the infrared spectra of reincarnated interstellar dust in cometary comae and circumstellar disks.

  15. THE REINCARNATION OF INTERSTELLAR DUST: THE IMPORTANCE OF ORGANIC REFRACTORY MATERIAL IN INFRARED SPECTRA OF COMETARY COMAE AND CIRCUMSTELLAR DISKS

    International Nuclear Information System (INIS)

    Kimura, Hiroshi

    2013-01-01

    We consider the reincarnation of interstellar dust to be reborn in protoplanetary disks as aggregates consisting of submicron-sized grains with a crystalline or amorphous silicate core and an organic-rich carbonaceous mantle. We find that infrared spectra of reincarnated interstellar dust reproduce emission peaks at correct wavelengths where the peaks were observed in cometary comae, debris disks, and protoplanetary disks if the volume fraction of organic refractory meets the constraints on elemental abundances. We discuss what we can learn from the infrared spectra of reincarnated interstellar dust in cometary comae and circumstellar disks

  16. Sensitivity to cocaine in adult mice is due to interplay between genetic makeup, early environment and later experience.

    Science.gov (United States)

    Di Segni, Matteo; Andolina, Diego; Coassin, Alessandra; Accoto, Alessandra; Luchetti, Alessandra; Pascucci, Tiziana; Luzi, Carla; Lizzi, Anna Rita; D'Amato, Francesca R; Ventura, Rossella

    2017-10-01

    Although early aversive postnatal events are known to increase the risk to develop psychiatric disorders later in life, rarely they determine alone the nature and outcome of the psychopathology, indicating that interaction with genetic factors is crucial for expression of psychopathologies in adulthood. Moreover, it has been suggested that early life experiences could have negative consequences or confer adaptive value in different individuals. Here we suggest that resilience or vulnerability to adult cocaine sensitivity depends on a "triple interaction" between genetic makeup x early environment x later experience. We have recently showed that Repeated Cross Fostering (RCF; RCF pups were fostered by four adoptive mothers from postnatal day 1 to postnatal day 4. Pups were left with the last adoptive mother until weaning) experienced by pups affected the response to a negative experience in adulthood in opposite direction in two genotypes leading DBA2/J, but not C57BL/6J mice, toward an "anhedonia-like" phenotype. Here we investigate whether exposure to a rewarding stimulus, instead of a negative one, in adulthood induces an opposite behavioral outcome. To test this hypothesis, we investigated the long-lasting effects of RCF on cocaine sensitivity in C57 and DBA female mice by evaluating conditioned place preference induced by different cocaine doses and catecholamine prefrontal-accumbal response to cocaine using a "dual probe" in vivo microdialysis procedure. Moreover, cocaine-induced c-Fos activity was assessed in different brain regions involved in processing of rewarding stimuli. Finally, cocaine-induced spine changes were evaluated in the prefrontal-accumbal system. RCF experience strongly affected the behavioral, neurochemical and morphological responses to cocaine in adulthood in opposite direction in the two genotypes increasing and reducing, respectively, the sensitivity to cocaine in C57 and DBA mice. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Operating a railway system within a challenging environment: Economic history and experiences of Zimbabwe’s national railways

    Directory of Open Access Journals (Sweden)

    Charles Mbohwa

    2008-11-01

    Full Text Available This paper presents a historical background to the development of the railways in Zimbabwe and then discusses their current state. Besides being a landlocked country in Southern Africa, Zimbabwe has since 2000 been saddled with socio-economic and political challenges which have seen a decline in all economic indices, hence posing some challenges to its railways. This article discusses the challenges faced by the railways as a result of high inflation, unstable currency exchange rate, brain drain, poor management, government interference in management, customs border delays, and energy shortage. The problems have been addressed in unique ways and unusual solutions are proposed. These include customer financing for maintenance and spares and the resuscitation of steam locomotives. The presented solutions, lessons and issues from this experience contribute to discussions and study of railway logistics in challenging environments. Finally, current and future research issues, which have a global appeal, are presented.

  18. Embodied thermal environments: an examination of older-people's sensory experiences in a variety of residential types

    International Nuclear Information System (INIS)

    Henshaw, Victoria; Guy, Simon

    2015-01-01

    Thermal sensations of space, namely temperature, humidity and the movement of air, can be difficult to separate from other sensory information such as the sound of fans or ventilation equipment, or the smell of damp or cool fresh air. Despite this factor, efforts to reduce the consumption of energy through the installation of low-carbon technologies including sealed whole-building systems frequently isolate the thermal environment and fail to recognise and respond to the influence of other sensory information on personal preferences and behaviours. Older people represent an increasing proportion of the UK's population, can be faced with a range of physiological challenges associated with ageing, and sometimes have long-established personal preferences. Drawing from data collected across the Conditioning Demand Project, this paper explores the embodied nature of older people's experiences of low-carbon and more traditional thermal technologies in private residences, extra-care housing and residential care-homes, focussing specifically upon auditory and olfactory stimulus. Exploring the management of the sensory experience across these settings, we analyse each case to inform the development of new design and policy approaches to tackling housing for older people. In doing so, we further build connections between energy research and debates around sensory urbanism. -- Highlights: •Some thermal technologies present particular sensory issues and problems for older people. •Older people use a range of sensory stimuli in evaluating and controlling thermal environments. •Older people use non-thermal sensory information when selecting between thermal technologies. •Sensory information plays an important role in thermal technology maintenance

  19. SN 2017dio: A Type-Ic Supernova Exploding in a Hydrogen-rich Circumstellar Medium

    Science.gov (United States)

    Kuncarayakti, Hanindyo; Maeda, Keiichi; Ashall, Christopher J.; Prentice, Simon J.; Mattila, Seppo; Kankare, Erkki; Fransson, Claes; Lundqvist, Peter; Pastorello, Andrea; Leloudas, Giorgos; Anderson, Joseph P.; Benetti, Stefano; Bersten, Melina C.; Cappellaro, Enrico; Cartier, Régis; Denneau, Larry; Della Valle, Massimo; Elias-Rosa, Nancy; Folatelli, Gastón; Fraser, Morgan; Galbany, Lluís; Gall, Christa; Gal-Yam, Avishay; Gutiérrez, Claudia P.; Hamanowicz, Aleksandra; Heinze, Ari; Inserra, Cosimo; Kangas, Tuomas; Mazzali, Paolo; Melandri, Andrea; Pignata, Giuliano; Rest, Armin; Reynolds, Thomas; Roy, Rupak; Smartt, Stephen J.; Smith, Ken W.; Sollerman, Jesper; Somero, Auni; Stalder, Brian; Stritzinger, Maximilian; Taddia, Francesco; Tomasella, Lina; Tonry, John; Weiland, Henry; Young, David R.

    2018-02-01

    SN 2017dio shows both spectral characteristics of a type-Ic supernova (SN) and signs of a hydrogen-rich circumstellar medium (CSM). Prominent, narrow emission lines of H and He are superposed on the continuum. Subsequent evolution revealed that the SN ejecta are interacting with the CSM. The initial SN Ic identification was confirmed by removing the CSM interaction component from the spectrum and comparing with known SNe Ic and, reversely, adding a CSM interaction component to the spectra of known SNe Ic and comparing them to SN 2017dio. Excellent agreement was obtained with both procedures, reinforcing the SN Ic classification. The light curve constrains the pre-interaction SN Ic peak absolute magnitude to be around {M}g=-17.6 mag. No evidence of significant extinction is found, ruling out a brighter luminosity required by an SN Ia classification. These pieces of evidence support the view that SN 2017dio is an SN Ic, and therefore the first firm case of an SN Ic with signatures of hydrogen-rich CSM in the early spectrum. The CSM is unlikely to have been shaped by steady-state stellar winds. The mass loss of the progenitor star must have been intense, \\dot{M}∼ 0.02{({ε }{{H}α }/0.01)}-1 ({v}{wind}/500 km s‑1) ({v}{shock}/10,000 km s‑1)‑3 M ⊙ yr‑1, peaking at a few decades before the SN. Such a high mass-loss rate might have been experienced by the progenitor through eruptions or binary stripping. Based on observations made with the NOT, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. This work is based (in part) on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile as part of PESSTO, (the Public ESO Spectroscopic Survey for Transient Objects Survey) ESO program 188.D-3003, 191.D-0935, 197.D-1075. Based on observations made with the Liverpool Telescope operated on the

  20. Natural Environments and Childhood Experiences Promoting Physical Activity, Examining the Mediational Effects of Feelings about Nature and Social Networks.

    Science.gov (United States)

    Calogiuri, Giovanna

    2016-04-21

    The importance of natural environments (NEs) for physical activity (PA) has been studied extensively. However, there is scant evidence to explain the motivational processes underlying the NE-PA relation. The aim of this study was to investigate the NE-PA relation using an ecological framework, focusing on perception of NEs, childhood experiences and possible intra- and inter-individual mediators. Data were retrieved from a cross-sectional survey among 2168 adults from all over Norway. In addition, the coverage of NEs by municipalities was retrieved from national registers. Logistic regression showed that, unlike the self-reported proximity to NEs, higher ratings of perceived supportiveness of NEs for PA predicted participation in NE-based PA for at least 60 min/week or 150 min/week, before and after controlling for socio-demographic characteristics. Reporting frequent experiences in nature during childhood was also an important predictor of higher levels of NE-based PA. Furthermore, a mediational analysis showed that the effect of both predictors was mediated by "feelings about nature" and "social networks". These findings indicate that to encourage the use of local NE for PA, not only should environmental perceptions be taken into account, positive feelings towards nature alongside opportunities to share activity in nature with others should also be promoted.

  1. Being Bullied in Virtual Environments: Experiences and Reactions of Male and Female Students to a Male or Female Oppressor

    Directory of Open Access Journals (Sweden)

    Nicole Krämer

    2018-03-01

    Full Text Available Bullying is a pressing societal problem. As such, it is important to gain a better understanding of the mechanisms involved in bullying and of resilience factors which might protect victims. Moreover, it is necessary to provide tools that can train potential victims to strengthen their resilience. To facilitate both of these goals, the current study tests a recently developed virtual environment that puts participants in the role of a victim who is being oppressed by a superior. In a 2 × 2 between-subjects experiment (N = 81, we measured the effects of gender of the oppressor and gender of the participant on psychophysiological reactions, subjective experiences and willingness to report the event. The results reveal that even when a male and a female bully show the exact same behavior, the male bully is perceived as more threatening. In terms of gender of the victim, the only difference that emerged was a more pronounced increase in heart rate in males. The results were moderated by the personality factors social gender, neuroticism, and need to belong, while self-esteem did not show any moderating influence.

  2. What to expect from immersive virtual environment exposure: influences of gender, body mass index, and past experience.

    Science.gov (United States)

    Stanney, Kay M; Hale, Kelly S; Nahmens, Isabelina; Kennedy, Robert S

    2003-01-01

    For those interested in using head-coupled PC-based immersive virtual environment (VE) technology to train, entertain, or inform, it is essential to understand the effects this technology has on its users. This study investigated potential adverse effects, including the sickness associated with exposure and extreme responses (emesis, flashbacks). Participants were exposed to a VE for 15 to 60 min, with either complete or streamlined navigational control and simple or complex scenes, after which time measures of sickness were obtained. More than 80% of participants experienced nausea, oculomotor disturbances, and/or disorientation, with disorientation potentially lasting > 24 hr. Of the participants, 12.9% prematurely ended their exposure because of adverse effects; of these, 9.2% experienced an emetic response, whereas only 1.2% of all participants experienced emesis. The results indicate that designers may be able to reduce these rates by limiting exposure duration and reducing the degrees of freedom of the user's navigational control. Results from gender, body mass, and past experience comparisons indicated it may be possible to identify those who will experience adverse effects attributable to exposure and warn such individuals. Applications for this research include military, entertainment, and any other interactive systems for which designers seek to avoid adverse effects associated with exposure.

  3. Natural Environments and Childhood Experiences Promoting Physical Activity, Examining the Mediational Effects of Feelings about Nature and Social Networks

    Directory of Open Access Journals (Sweden)

    Giovanna Calogiuri

    2016-04-01

    Full Text Available The importance of natural environments (NEs for physical activity (PA has been studied extensively. However, there is scant evidence to explain the motivational processes underlying the NE-PA relation. The aim of this study was to investigate the NE-PA relation using an ecological framework, focusing on perception of NEs, childhood experiences and possible intra- and inter-individual mediators. Data were retrieved from a cross-sectional survey among 2168 adults from all over Norway. In addition, the coverage of NEs by municipalities was retrieved from national registers. Logistic regression showed that, unlike the self-reported proximity to NEs, higher ratings of perceived supportiveness of NEs for PA predicted participation in NE-based PA for at least 60 min/week or 150 min/week, before and after controlling for socio-demographic characteristics. Reporting frequent experiences in nature during childhood was also an important predictor of higher levels of NE-based PA. Furthermore, a mediational analysis showed that the effect of both predictors was mediated by “feelings about nature” and “social networks”. These findings indicate that to encourage the use of local NE for PA, not only should environmental perceptions be taken into account, positive feelings towards nature alongside opportunities to share activity in nature with others should also be promoted.

  4. The construction of work–life balance: The experience of Black employees in a call-centre environment

    Directory of Open Access Journals (Sweden)

    Sonia C.B. Potgieter

    2010-08-01

    Research purpose: The objective of the study was to explore Black employees’ construction of work–life balance in a customer care environment. Motivation for the study: The conceptual debate regarding the construct of work–life balance in general as well as limited qualitative research with regard to Black employees’ experience of work–life balance in a South African context motivated the study. Research design, approach and method: This qualitative study was designed from an interpretivist perspective. Ten employees, selected through purposeful sampling, participated in the study. Data was gathered through in-depth interviews and grounded theory was applied during data analysis. Main findings: The grounded theory analysis of the data yielded six themes central to participants’ construction of work–life balance. The findings suggest that work–life balance is conceptualised as a continuous, subjective and holistic valuation of satisfaction derived from multiple roles in relation to the importance to the individual at a given point in time. Practical/managerial implications: Findings provide valuable managerial information to guide suitable strategies enhancing the work–life balance experience and by implication employees’ general wellbeing, job satisfaction and commitment. Contributions/value-add: This study contributes to the evolving body of knowledge with regard to work–life balance and provides a unique context-specific perspective to the conceptual understanding of the construct.

  5. The relationship between internet-gaming experience and executive functions measured by virtual environment compared with conventional laboratory multitasks.

    Directory of Open Access Journals (Sweden)

    Yong-Quan Chen

    Full Text Available The aim of this study was to investigate if individuals with frequent internet gaming (IG experience exhibited better or worse multitasking ability compared with those with infrequent IG experience. The individuals' multitasking abilities were measured using virtual environment multitasks, such as Edinburgh Virtual Errands Test (EVET, and conventional laboratory multitasks, such as the dual task and task switching. Seventy-two young healthy college students participated in this study. They were split into two groups based on the time spent on playing online games, as evaluated using the Internet Use Questionnaire. Each participant performed EVET, dual-task, and task-switching paradigms on a computer. The current results showed that the frequent IG group performed better on EVET compared with the infrequent IG group, but their performance on the dual-task and task-switching paradigms did not differ significantly. The results suggest that the frequent IG group exhibited better multitasking efficacy if measured using a more ecologically valid task, but not when measured using a conventional laboratory multitasking task. The differences in terms of the subcomponents of executive function measured by these task paradigms were discussed. The current results show the importance of the task effect while evaluating frequent internet gamers' multitasking ability.

  6. In vitro experimental environments lacking or containing soil disparately affect competition experiments of Aspergillus flavus and co-occurring fungi in maize grains.

    Science.gov (United States)

    Falade, Titilayo D O; Syed Mohdhamdan, Sharifah H; Sultanbawa, Yasmina; Fletcher, Mary T; Harvey, Jagger J W; Chaliha, Mridusmita; Fox, Glen P

    2016-07-01

    In vitro experimental environments are used to study interactions between microorganisms, and to predict dynamics in natural ecosystems. This study highlights that experimental in vitro environments should be selected to match closely the natural environment of interest during in vitro studies to strengthen extrapolations about aflatoxin production by Aspergillus and competing organisms. Fungal competition and aflatoxin accumulation were studied in soil, cotton wool or tube (water-only) environments, for Aspergillus flavus competition with Penicillium purpurogenum, Fusarium oxysporum or Sarocladium zeae within maize grains. Inoculated grains were incubated in each environment at two temperature regimes (25 and 30°C). Competition experiments showed interaction between the main effects of aflatoxin accumulation and the environment at 25°C, but not so at 30°C. However, competition experiments showed fungal populations were always interacting with their environments. Fungal survival differed after the 72-h incubation in different experimental environments. Whereas all fungi incubated within the soil environment survived, in the cotton wool environment none of the competitors of A. flavus survived at 30°C. With aflatoxin accumulation, F. oxysporum was the only fungus able to interdict aflatoxin production at both temperatures. This occurred only in the soil environment and fumonisins accumulated instead. Smallholder farmers in developing countries face serious mycotoxin contamination of their grains, and soil is a natural reservoir for the associated fungal propagules, and a drying and storage surface for grains on these farms. Studying fungal dynamics in the soil environment and other environments in vitro can provide insights into aflatoxin accumulation post-harvest.

  7. POLARIMETRY WITH THE GEMINI PLANET IMAGER: METHODS, PERFORMANCE AT FIRST LIGHT, AND THE CIRCUMSTELLAR RING AROUND HR 4796A

    International Nuclear Information System (INIS)

    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

    2015-01-01

    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

  8. Development of Experience-based Learning about Atmospheric Environment with Quantitative Viewpoint aimed at Education for Sustainable Development

    Science.gov (United States)

    Saitoh, Y.; Tago, H.

    2014-12-01

    The word "ESD (Education for Sustainable Development)" has spread over the world in UN decade (2005 - 2014), and the momentum of the educational innovation aimed at ESD also has grown in the world. Especially, environmental educations recognized as one of the most important ESD have developed in many countries including Japan, but most of those are still mainly experiences in nature. Those could develop "Respect for Environment" of the educational targets of ESD, however we would have to take a further step in order to enhance "Ability of analysis and thinking logically about the environment" which are also targets of ESD.Thus, we developed experienced-learning program about atmospheric particulate matter (PM2.5), for understanding the state of the environment objectively based on quantitative data. PM2.5 is known for harmful, and various human activities are considered a source of it, therefore environmental standards for PM2.5 have been established in many countries. This program was tested on junior high school students of 13 - 15 years old, and the questionnaire survey also was conducted to them before and after the program for evaluating educational effects. Students experienced to measure the concentration of PM2.5 at 5 places around their school in a practical manner. The measured concentration of PM2.5 ranged from 19 to 41 μg/m3/day, that value at the most crowded roadside exceeded Japan's environmental standard (35 μg/m3/day). Many of them expressed "Value of PM2.5 is high" in their individual discussion notes. As a consistent with that, the answer "Don't know" to the question "What do you think about the state of the air?" markedly decreased after the program, on the other hand the answer "Pollution" to the same question increased instead. From above-mentioned, it was considered that they could judge the state of the air objectively. Consequently, the questionnaire result "Concern about Air Pollution" increased significantly after the program compared

  9. The construction of work–life balance: The experience of Black employees in a call-centre environment

    Directory of Open Access Journals (Sweden)

    Sonia C.B. Potgieter

    2010-03-01

    Full Text Available Orientation: Work–life balance, as a crucial aspect of employee and organisational wellness, remains an interesting field of research, especially due to the changing demographic employee profile.Research purpose: The objective of the study was to explore Black employees’ construction of work–life balance in a customer care environment.Motivation for the study: The conceptual debate regarding the construct of work–life balance in general as well as limited qualitative research with regard to Black employees’ experience of work–life balance in a South African context motivated the study.Research design, approach and method: This qualitative study was designed from an interpretivist perspective. Ten employees, selected through purposeful sampling, participated in the study. Data was gathered through in-depth interviews and grounded theory was applied during data analysis.Main findings: The grounded theory analysis of the data yielded six themes central to participants’ construction of work–life balance. The findings suggest that work–life balance is conceptualised as a continuous, subjective and holistic valuation of satisfaction derived from multiple roles in relation to the importance to the individual at a given point in time.Practical/managerial implications: Findings provide valuable managerial information to guide suitable strategies enhancing the work–life balance experience and by implication employees’ general wellbeing, job satisfaction and commitment.Contributions/value-add: This study contributes to the evolving body of knowledge with regard to work–life balance and provides a unique context-specific perspective to the conceptual understanding of the construct.

  10. Acoustic Heritage and Audio Creativity: the Creative Application of Sound in the Representation, Understanding and Experience of Past Environments

    Directory of Open Access Journals (Sweden)

    Damian Murphy

    2017-06-01

    Full Text Available Acoustic Heritage is one aspect of archaeoacoustics, and refers more specifically to the quantifiable acoustic properties of buildings, sites and landscapes from our architectural and archaeological past, forming an important aspect of our intangible cultural heritage. Auralisation, the audio equivalent of 3D visualisation, enables these acoustic properties, captured via the process of measurement and survey, or computer-based modelling, to form the basis of an audio reconstruction and presentation of the studied space. This article examines the application of auralisation and audio creativity as a means to explore our acoustic heritage, thereby diversifying and enhancing the toolset available to the digital heritage or humanities researcher. The Open Acoustic Impulse Response (OpenAIR library is an online repository for acoustic impulse response and auralisation data, with a significant part having been gathered from a broad range of heritage sites. The methodology used to gather this acoustic data is discussed, together with the processes used in generating and calibrating a comparable computer model, and how the data generated might be analysed and presented. The creative use of this acoustic data is also considered, in the context of music production, mixed media artwork and audio for gaming. More relevant to digital heritage is how these data can be used to create new experiences of past environments, as information, interpretation, guide or artwork and ultimately help to articulate new research questions and explorations of our acoustic heritage.

  11. OASYS (OrAnge SYnchrotron Suite): an open-source graphical environment for x-ray virtual experiments

    Science.gov (United States)

    Rebuffi, Luca; Sanchez del Rio, Manuel

    2017-08-01

    The evolution of the hardware platforms, the modernization of the software tools, the access to the codes of a large number of young people and the popularization of the open source software for scientific applications drove us to design OASYS (ORange SYnchrotron Suite), a completely new graphical environment for modelling X-ray experiments. The implemented software architecture allows to obtain not only an intuitive and very-easy-to-use graphical interface, but also provides high flexibility and rapidity for interactive simulations, making configuration changes to quickly compare multiple beamline configurations. Its purpose is to integrate in a synergetic way the most powerful calculation engines available. OASYS integrates different simulation strategies via the implementation of adequate simulation tools for X-ray Optics (e.g. ray tracing and wave optics packages). It provides a language to make them to communicate by sending and receiving encapsulated data. Python has been chosen as main programming language, because of its universality and popularity in scientific computing. The software Orange, developed at the University of Ljubljana (SLO), is the high level workflow engine that provides the interaction with the user and communication mechanisms.

  12. The effect of farrowing environment and previous experience on the maternal behaviour of sows in indoor pens and outdoor huts.

    Science.gov (United States)

    Wülbers-Mindermann, M; Berg, C; Illmann, G; Baulain, U; Algers, B

    2015-04-01

    Outdoor farrowing huts facilitate a less restricted maternal behaviour in sows compared with sows kept indoors in farrowing pens. The aim of our study was to investigate whether there are behavioural differences between primiparous sows kept outdoors in farrowing huts and indoors in pens, and whether the maternal behaviour during the second parity, when all sows were kept outdoors in farrowing huts, would differ between sows that have experienced the indoor or the outdoor environment, respectively, during their first parturition. A total of 26 Yorkshire×Swedish Landrace sows were studied. Of these, 11 sows were housed outdoors in farrowing huts during both parturitions (group=OUTOUT). The other 15 sows were kept indoors in a barn with single farrowing pens during their first parturition. During their second parturition, sows were kept outdoors in farrowing huts (group=INOUT). The behaviour was video recorded from 2 h prepartum to 48 h postpartum. The sows' responsiveness to playbacks of a piglet's screams was tested on days 2 to 3 postpartum. Parity 1: during the last 2 h prepartum, OUTOUT sows had a higher proportion of observations in the sternal lying position (Pbehavioural differences between INOUT and OUTOUT sows. In conclusion, it is not problematic for a second parity sow with initial maternal experience from an indoor farrowing pen to be kept outdoors in farrowing huts during its following farrowing.

  13. Indian deep-sea environment experiment (INDEX): Monitoring the restoration of marine enviroment after artificial disturbance to simulate deep-sea mining in central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, R.

    the restoration of marine environment after artificial disturbance to simulate deep-sea mining in Central Indian Basin Guest Editor Rahul Sharma Note from guest editor A special issue on Indian Deep-sea Environment Experiment (INDEX) conducted by the scientists... in Geochemical Associations in Artificially Disturbed Deep-Sea Sediments B. Nagender Nath, G. Parthiban, S. Banaulikar, and Subhadeep Sarkar Marine Georesources and Geotechnology, 24:61–62, 2006 Copyright # Taylor & Francis Group, LLC ISSN: 1064-119X print/1521...

  14. A Case Study of the Experiences of Instructors and Students in a Virtual Learning Environment (VLE) with Different Cultural Backgrounds

    Science.gov (United States)

    Lim, Keol; Kim, Mi Hwa

    2015-01-01

    The use of virtual learning environments (VLEs) has become more common and educators recognized the potential of VLEs as educational environments. The learning community in VLEs can be a mixture of people from all over the world with different cultural backgrounds. However, despite many studies about the use of virtual environments for learning,…