WorldWideScience

Sample records for huygens probe entry

  1. Huygens probe entry dynamic model and accelerometer data analysis

    Science.gov (United States)

    Colombatti, Giacomo; Aboudan, Alessio; Ferri, Francesca; Angrilli, Francesco

    2008-04-01

    During the first phase of Huygens arrival into Titan's atmosphere the probe is subjected to gravitational and aerodynamic forces in aerodynamic hypersonic regime. Atmospheric drag exerts a strong deceleration on the capsule measured by Huygens atmospheric structure instrument (HASI) servo accelerometer. A 6 DOF (Degree of Freedom) model of the Huygens probe entry dynamics has been developed and used for data analysis. The accelerometer data are analysed and the model allows the retrieval of dynamics information of Huygens probe from 1545 km altitude down to end of the entry phase. Probe's initial conditions (velocity and position) were refined to match the measured deceleration profile resulting in a different altitude at interface epoch with respect to those of the Cassini Navigation Team. Velocity and position of probe at interface epoch are compatible with those used by Descent Trajectory Working Group (DTWG). Measurements acquired before atmosphere detection are used to estimate probe's angular rate, bound attitude and characterise the angle of attack profile which results to be lower than 4∘ during the whole entry. Probe's spin calculated (6.98 RPM) is slightly different with respect to DTWG of 7.28 RPM but considering a 2% error in the Inertia matrix these results are inside the 1-σ error band.

  2. New Results on Titan’s Atmosphere and Surface from Huygens Probe Measurements

    Science.gov (United States)

    Lorenz, Ralph

    2013-10-01

    The global Titan perspective afforded by ongoing Cassini observations, and prospects for future in-situ exploration, have prompted a re-examination of Huygens data, yielding new results in several areas. Gravity waves have been detected (Lorenz, Ferri and Young, submitted) in the HASI descent temperature data, with 2K amplitude. These waves are seen above about 60km, and analysis suggests they may therefore be controlled by interaction of upward-propagating waves with the zonal wind field. A curious cessation of detection of sound pulses by a Surface Science Package ultrasound instrument about 15 minutes after the probe landed appears to be best explained (Lorenz et al., submitted) by an accumulation of polyatomic vapors such as ethane, sweated out of the ground by the warm probe. Such gases have high acoustic attenuation, and were independently measured by the probe GCMS. A new integrated timeline product, which arranges second-by-second measurements from several Huygens sensors on a convenient, common tabulation, has been archived on the PDS Atmospheres node. Also archived is an independent retrieval of Doppler information from VLBI receivers that has a higher time resolution than the DWE archive product, and an expanded event summary product that documents when key observations, system events and anomalies occurred. Finally, a troubling discrepancy exists between radio occultation and infrared soundings from Cassini, and the lower stratospheric temperature retrieved from the HASI accelerometer record. Two factors may contribute to this discrepancy - the assumed probe mass history, and the assumed zonal wind profile. The sensitivity of the recovered temperature profile to these factors is examined : in particular it is noted that the speed relative to the atmosphere in the late part of entry, when the hypersonic entry speed has been largely bled away by drag, is particularly sensitive to assumed winds, and it is in this altitude region where the recovered density

  3. ICES ON TITAN: LABORATORY MEASUREMENTS THAT COMPLEMENT THE HUYGENS PROBE

    Energy Technology Data Exchange (ETDEWEB)

    J. ROBINSON; ET AL

    2000-08-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The composition of the cold bodies in the outer solar system may hold some of the key molecular clues concerning the composition of the prestellax molecular cloud that gave rise to the solar system. We studied the physical chemistry and heterogeneous (gas/surface) reactivity of extraterrestrial ice analogs of the surfaces of Saturn's moon Titan. This program coupled our surface spectroscopic techniques with physical adsorption measurements. We addressed several of the pressing questions regarding Titan such as: Is storage of hydrocarbons in Titan's water ice crust feasible? Do heterogeneous processes influence the atmospheric chemical composition of Titan? Are phase transitions to be expected? These data can be incorporated into photochemical models with the goal of improved modeling of the chemical composition and meteorology of Titan's atmosphere. Titan will be probed by the Cassini-Huygens Mission. Our results on Titan ice analogs can be used to help interpret the mission data.

  4. First Results From the Gas Chromatograph Mass Spectrometer (GCMS) Experiment on the Cassini-Huygens Probe

    Science.gov (United States)

    Niemann, Hasso B.; Demick, J.; Haberman, J.; Harpold, D.; Kasprzak, W.; Raaen, E.; Way, S.; Atreya, S.; Carignan, G.; Bauer, S.

    2005-01-01

    The Huygens Probe of the Cassini Huygens Mission entered the atmosphere of the moon Titan on January 14,2005. The GCMS was part of the instrument complement on the Probe to measure in situ the chemical composition of the atmosphere during the probe descent and to support the Aerosol Collector Pyrolyser (ACP) experiment by serving as detector for the pyrolization products. The GCMS employed a quadrupole mass filter with a secondary electron multiplier detection system and a gas sampling system providing continuous direct atmospheric composition measurements and batch sampling through three gas chromatographic (GC) columns. The mass spectrometer employed five electron impact ion sources with available electron energies of either 70 or 25 eV. Three ion sources served as detectors for the GC columns and two were dedicated to direct atmosphere sampling and ACP gas sampling, respectively. The GCMS gas inlet was heated to prevent condensation, and served to evaporate surface constituents after impact.

  5. VLBI experiment with the Huygens Probe during its descent in the atmosphere of Titan : An evidence for meridional wind

    NARCIS (Netherlands)

    Pogrebenko, Sergei; Gurvits, Leonid; Avruch, Ian; Cimo, Giuseppe; Team, Huygens VLBI Tracking

    Phase-referencing VLBI observations of the Huygens Probe were performed during its descent in the atmosphere of Titan on 14 January 2005 using a global network of 17 radio telescopes. The Probe's position in the Titanographic frame was determined with the accuracy of about 1 km relative to a priori

  6. Project Prometheus and Future Entry Probe Missions

    Science.gov (United States)

    Spilker, Thomas R.

    2005-01-01

    A viewgraph presentation on project Prometheus and future entry probe missions is shown. The topics include: 1) What Is Project Prometheus?; 2) What Capabilities Can Project Prometheus Offer? What Mission Types Are Being Considered?; 3) Jupiter Icy Moons Orbiter (JIMO); 4) How Are Mission Opportunities Changing?; 5) Missions Of Interest a Year Ago; 6) Missions Now Being Considered For Further Study; 7) Galileo-Style (Conventional) Probe Delivery; 8) Galileo-Style Probe Support; 9) Conventional Delivery and Support of Multiple Probes; 10) How Entry Probe Delivery From an NEP Vehicle Is Different; and 11) Concluding Remarks.

  7. The Huygens Atmospheric Structure Instrument (HASI): Expected Results at Titan and Performance Verification in Terrestrial Atmosphere

    Science.gov (United States)

    Ferri, F.; Fulchignoni, M.; Colombatti, G.; Stoppato, P. F. Lion; Zarnecki, J. C.; Harri, A. M.; Schwingenschuh, K.; Hamelin, M.; Flamini, E.; Bianchini, G.; Angrilli, F.

    2005-01-01

    The Huygens ASI is a multi-sensor package resulting from an international cooperation, it has been designed to measure the physical quantities characterizing Titan's atmosphere during the Huygens probe mission. On 14th January, 2005, HASI will measure acceleration, pressure, temperature and electrical properties all along the Huygens probe descent on Titan in order to study Titan s atmospheric structure, dynamics and electric properties. Monitoring axial and normal accelerations and providing direct pressure and temperature measurements during the descent, HASI will mainly contribute to the Huygens probe entry and trajectory reconstruction. In order to simulate the Huygens probe descent and verify HASI sensors performance in terrestrial environment, stratospheric balloon flight experiment campaigns have been performed, in collaboration with the Italian Space Agency (ASI). The results of flight experiments have allowed to determine the atmospheric vertical profiles and to obtain a set of data for the analysis of probe trajectory and attitude reconstruction.

  8. Lessons learned from planetary entry probe missions

    Science.gov (United States)

    Niemann, Hasso; Atreya, Sushil K.; Kasprzak, Wayne

    Probing the atmospheres and surfaces of the planets and their moons with fast moving entry probes has been a very useful and essential technique to obtain in situ or quasi in situ scientific data (ground truth) which could not otherwise be obtained from fly by or orbiter only missions and where balloon, aircraft or lander missions are too complex and too costly. Planetary entry probe missions have been conducted successfully on Venus, Mars, Jupiter and Titan after having been first demonstrated in the Earth's atmosphere. Future planetary missions should also include more entry probe missions back to Venus and to the outer planets. The success of and science returns from past missions, the need for more and unique data, and a continuously advancing technology generate confidence that future missions will be even more successful with respect to science return and technical performance. There are, however, unique challenges associated with entry probe missions and with building instruments for an entry probe, as compared to orbiters, landers, or rovers. Conditions during atmospheric entry are extreme. There are operating time constraints due to the usually short duration of the probe descent, and the instruments experience rapid environmental changes in temperature and pressure. In addition, there are resource limitations, i.e. mass, power, size and bandwidth. Because of the protective heat shield and the high acceleration the probe experiences during entry, the ratio of payload to total probe mass is usually much smaller than in other missions. Finally, the demands on the instrument design are determined in large part by conditions (pressure, temperature, composition) unique to the particular body under study, and as a result, there is no one-size-fits-all instrument for an atmospheric probe. Many of these requirements are more easily met by miniaturizing the probe instrumentation and consequently reducing the required size of the probe. Improved heat shield

  9. Using speed of sound measurements to constrain the Huygens probe descent profile

    Science.gov (United States)

    Svedhem, Håkan; Lebreton, Jean-Pierre; Zarnecki, John; Hathi, Brijen

    2004-02-01

    The Acoustic Properties Investigation (API) is a set of sensors for acoustic measurements in gases or liquids, making a part of the Surface Science Package (SSP) on the Huygens probe. It consists of two units, API-V (Velocity of sound) and API-S (Sounding). The API-V has two ultrasonic transducers sending and receiving acoustic pulses over an unobstructed path of 15 cm. An accurate timing circuit is measuring the time it takes to propagate over the distance. Measurements are made in both directions to eliminate the effect of a constant drift of the medium. The transducers have been optimised to operate at low pressure (high altitude) and will operate from about 60 km down to the surface. They will also perform well in case of landing in a liquid. The API-S unit is an acoustic sounder, sending short pulses at 15 kHz every second and listening for echoes in between. It will detect droplets in the atmosphere and for the last 100 m it will characterise the acoustic scattering properties of the surface below. It will also give an accurate value for the descend velocity during the last 100 m. In case of landing in a (liquid) lake/ocean it will measure the depth of the late-ocean down to a maximum of about 1000 m. Accurate measurements of the velocity of sound will, together with knowledge on the temperature, enable the mean molecular weight to be calculated along the descent trajectory. The temperature will be measured by complementary sensors inside the SSP Top Hat, near the API-V, and to a high accuracy by the HASI instrument at the periphery of the Huygens probe. The API units and associated electronics has been designed and build at the Research and Scientific Support Department at ESTEC, where also the testing and initial calibration has been done. Detailed calibration has been performed with different gas mixtures and at different temperatures in the Titan simulation chamber at the University of Kent, Canterbury, UK. Further supporting studies are planned in the

  10. The Hera Saturn Entry Probe Mission

    CERN Document Server

    Mousis, O; Spilker, T; Venkatapathy, E; Poncy, J; Frampton, R; Coustenis, A; Reh, K; Lebreton, J -P; Fletcher, L N; Hueso, R; Amato, M J; Colaprete, A; Ferri, F; Stam, D; Wurz, P; Atreya, S; Aslam, S; Banfield, D J; Calcutt, S; Fischer, G; Holland, A; Keller, C; Kessler, E; Leese, M; Levacher, P; Morse, A; Munoz, O; Renard, J -B; Sheridan, S; Schmider, F -X; Snik, F; Waite, J H; Bird, M; Cavalié, T; Deleuil, M; Fortney, J; Gautier, D; Guillot, T; Lunine, J I; Marty, B; Nixon, C; Orton, G S; Sanchez-Lavega, A

    2015-01-01

    The Hera Saturn entry probe mission is proposed as an M--class mission led by ESA with a contribution from NASA. It consists of one atmospheric probe to be sent into the atmosphere of Saturn, and a Carrier-Relay spacecraft. In this concept, the Hera probe is composed of ESA and NASA elements, and the Carrier-Relay Spacecraft is delivered by ESA. The probe is powered by batteries, and the Carrier-Relay Spacecraft is powered by solar panels and batteries. We anticipate two major subsystems to be supplied by the United States, either by direct procurement by ESA or by contribution from NASA: the solar electric power system (including solar arrays and the power management and distribution system), and the probe entry system (including the thermal protection shield and aeroshell). Hera is designed to perform in situ measurements of the chemical and isotopic compositions as well as the dynamics of Saturn's atmosphere using a single probe, with the goal of improving our understanding of the origin, formation, and ev...

  11. The Hera Saturn entry probe mission

    Science.gov (United States)

    Mousis, O.; Atkinson, D. H.; Spilker, T.; Venkatapathy, E.; Poncy, J.; Frampton, R.; Coustenis, A.; Reh, K.; Lebreton, J.-P.; Fletcher, L. N.; Hueso, R.; Amato, M. J.; Colaprete, A.; Ferri, F.; Stam, D.; Wurz, P.; Atreya, S.; Aslam, S.; Banfield, D. J.; Calcutt, S.; Fischer, G.; Holland, A.; Keller, C.; Kessler, E.; Leese, M.; Levacher, P.; Morse, A.; Muñoz, O.; Renard, J.-B.; Sheridan, S.; Schmider, F.-X.; Snik, F.; Waite, J. H.; Bird, M.; Cavalié, T.; Deleuil, M.; Fortney, J.; Gautier, D.; Guillot, T.; Lunine, J. I.; Marty, B.; Nixon, C.; Orton, G. S.; Sánchez-Lavega, A.

    2016-10-01

    The Hera Saturn entry probe mission is proposed as an M-class mission led by ESA with a contribution from NASA. It consists of one atmospheric probe to be sent into the atmosphere of Saturn, and a Carrier-Relay spacecraft. In this concept, the Hera probe is composed of ESA and NASA elements, and the Carrier-Relay Spacecraft is delivered by ESA. The probe is powered by batteries, and the Carrier-Relay Spacecraft is powered by solar panels and batteries. We anticipate two major subsystems to be supplied by the United States, either by direct procurement by ESA or by contribution from NASA: the solar electric power system (including solar arrays and the power management and distribution system), and the probe entry system (including the thermal protection shield and aeroshell). Hera is designed to perform in situ measurements of the chemical and isotopic compositions as well as the dynamics of Saturn's atmosphere using a single probe, with the goal of improving our understanding of the origin, formation, and evolution of Saturn, the giant planets and their satellite systems, with extrapolation to extrasolar planets. Hera's aim is to probe well into the cloud-forming region of the troposphere, below the region accessible to remote sensing, to the locations where certain cosmogenically abundant species are expected to be well mixed. By leading to an improved understanding of the processes by which giant planets formed, including the composition and properties of the local solar nebula at the time and location of giant planet formation, Hera will extend the legacy of the Galileo and Cassini missions by further addressing the creation, formation, and chemical, dynamical, and thermal evolution of the giant planets, the entire solar system including Earth and the other terrestrial planets, and formation of other planetary systems.

  12. Titan Imagery with Keck AO during and after Probe Entry

    Energy Technology Data Exchange (ETDEWEB)

    de Pater, I; Adamkovics, M; Bouchez, A H; Brown, M E; Gibbard, S G; Marchis, F; Roe, H G; Schaller, E L; Young, E

    2006-02-03

    We present adaptive optics data from the 10-m W.M. Keck telescope that were taken during the time the Huygens probe descended through Titan's atmosphere, and on the days following touch-down. The spatial resolution of the images is typically {approx}0.04-inch, or {approx}240 km on Titan (60 km/pixel). No probe entry signal was detected at levels exceeding 0.8 {micro}Jy (3-{sigma}) per pixel (0.01-inch), which although within the range of predicted flux levels, cannot constrain any models. We present data on Titan's surface, troposphere and stratosphere during the days following probe entry, when the solar phase angle varied from 0.05{sup o} up to 0.8{sup o}, with the Sun in the West. Contrary to expectation, the data often showed the East side to be brightest. Adding data obtained with Keck and Gemini over the past few years reveals that the East-West asymmetry can be explained by a combination of the solar phase angle effect together with a general preponderance of haze on Titan's East or morning hemisphere. The troposphere was characterized by quiescent weather; only a few small clouds were present near the south pole, at typical altitudes of 30-40 km. While stratospheric haze was prominent over the northern hemisphere, tropospheric haze dominated the south, from the S. pole up to latitudes of {approx} -45{sup o}. An intriguing observation is that obtained at 1.22 {micro}m, which revealed haze in the form of a collar at -60{sup o}, in contrast to the polar haze cap as usually seen. A comparison of narrow band JHK images of Titan's surface with that obtained by Cassini ISS shows a striking resemblance in small-scale features. After a decent attempt to remove the atmosphere from the images, the surface contrast between dark and bright areas may be larger at 2 {micro}m than at 1.6 and 1.3 {micro}m. If true, this could imply that the dark areas on Titan's surface are covered by a coarser grained frost than the bright areas, and/or that there

  13. The electrical properties of Titan's surface at the Huygens landing site measured with the PWA-HASI Mutual Impedance Probe. New approach and new findings

    Science.gov (United States)

    Hamelin, Michel; Lethuillier, Anthony; Le Gall, Alice; Grard, Réjean; Béghin, Christian; Schwingenschuh, Konrad; Jernej, Irmgard; López-Moreno, José-Juan; Brown, Vic; Lorenz, Ralph D.; Ferri, Francesca; Ciarletti, Valérie

    2016-05-01

    Ten years after the successful landing of the Huygens Probe on the surface of Titan, we reassess the derivation of ground complex permittivity using the PWA-MIP/HASI measurements (Permittivity, Waves and Altimetry-Mutual Impedance Probe/Huygens Atmospheric Structure Instrument) at the frequencies 45, 90 and 360 Hz. For this purpose, we have developed a numerical method, namely "the capacity-influence matrix method", able to account for new insights on the Huygens Probe attitude at its final resting position. We find that the surface of Titan at the landing site has a dielectric constant of 2.5 ± 0.3 and a conductivity of 1.2 ± 0.6 nS/m, in agreement with previously published results but with much more reliable error estimates. These values speak in favour of a photochemical origin of the material in the first meter of the subsurface. We also propose, for the first time, a plausible explanation for the sudden change observed by PWA-MIP ∼11 min after landing: this change corresponds to a drop in the ground conductivity, probably due to the removal of a superficial conductive layer in association with the release of volatile materials warmed by the Huygens Probe.

  14. Planetary Entry Probes and Mass Spectroscopy: Tools and Science Results from In Situ Studies of Planetary Atmospheres and Surfaces

    Science.gov (United States)

    Niemann, Hasso B.

    2007-01-01

    Probing the atmospheres and surfaces of the planets and their moons with fast moving entry probes has been a very useful and essential technique to obtain in situ or quasi in situ scientific data (ground truth) which could not otherwise be obtained from fly by or orbiter only missions and where balloon, aircraft or lander missions are too complex and costly. Planetary entry probe missions have been conducted successfully on Venus, Mars, Jupiter and Titan after having been first demonstrated in the Earth's atmosphere. Future missions will hopefully also include more entry probe missions back to Venus and to the outer planets. 1 he success of and science returns from past missions, the need for more and better data, and a continuously advancing technology generate confidence that future missions will be even more successful with respect to science return and technical performance. I'he pioneering and tireless work of Al Seiff and his collaborators at the NASA Ames Research Center had provided convincing evidence of the value of entry probe science and how to practically implement flight missions. Even in the most recent missions involving entry probes i.e. Galileo and Cassini/Huygens A1 contributed uniquely to the science results on atmospheric structure, turbulence and temperature on Jupiter and Titan.

  15. Convective and radiative heating of a Saturn entry probe

    Science.gov (United States)

    Tiwari, S. N.; Szema, K. Y.; Moss, J. N.; Subramanian, S. V.

    1984-01-01

    The extent of convective and radiative heating for a Saturn entry probe is investigated in the absence and presence of ablation mass injection. The flow in the shock layer is assumed to be axisymmetric, viscous and in local thermodynamic equilibrium. The importance of chemical nonequilibrium effects for both the radiative and convective nonblowing surface heating rates is demonstrated for prescribed entry conditions. Results indicate that the nonequilibrium chemistry can significantly influence the rate of radiative heating to the entry probes. With coupled carbon-phenolic ablation injection, the convective heating rates are reduced substantially. Turbulence has little effect on radiative heating but it increases the convective heating considerably.

  16. Second space Christmas for ESA: Huygens to begin its final journey to Titan/ Media activities.

    Science.gov (United States)

    2004-12-01

    At 1.25 billion km from Earth, after a 7-year journey through the Solar system, ESA’s Huygens probe is about to separate from the Cassini orbiter to enter a ballistic trajectory toward Titan, the largest and most mysterious moon of Saturn, in order to dive into its atmosphere on 14 January. This will be the first man-made object to explore in-situ this unique environment, whose chemistry is assumed to be very similar to that of the early Earth just before life began, 3.8 billion years ago. The Cassini-Huygens pair, a joint mission conducted by NASA, ESA and the Italian space agency (ASI), was launched into space on 15 October 1997. With the help of several gravity assist manoeuvres during flybys of Venus, Earth and Jupiter, it took almost 7 years for the spacecraft to reach Saturn. The Cassini orbiter, carrying Huygens on its flank, entered an orbit around Saturn on 1 July 2004, and began to investigate the ringed planet and its moons for a mission that will last at least four years. The first distant flyby of Titan took place on 2-3 July 2004. It provided data on Titan's atmosphere which were confirmed by the data obtained during the first close flyby on 26 October 2004 at an altitude of 1174 km. These data were used to validate the entry conditions of the Huygens probe. A second close flyby of Titan by Cassini-Huygens at an altitude of 1200 km is scheduled on 13 December and will provide additional data to further validate the entry conditions of the Huygens probe. On 17 December the orbiter will be placed on a controlled collision course with Titan in order to release Huygens on the proper trajectory, and on 21 December (some dates and times are subject to minor adjustment for operational reasons, except the entry time on 14 January which is know to within an accuracy of under 2 minutes) all systems will be set up for separation and the Huygens timers will be set to wake the probe a few hours before its arrival at Titan. The Huygens probe is due to separate on

  17. Shock Radiation Tests for Saturn and Uranus Entry Probes

    Science.gov (United States)

    Cruden, Brett A.; Bogdanoff, David W.

    2014-01-01

    This paper describes a test series in the Electric Arc Shock Tube at NASA Ames Research Center with the objective of quantifying shock-layer radiative heating magnitudes for future probe entries into Saturn and Uranus atmospheres. Normal shock waves are measured in Hydrogen/Helium mixtures (89:11 by mole) at freestream pressures between 13-66 Pa (0.1-0.5 Torr) and velocities from 20-30 km/s. No shock layer radiation is detected below 25 km/s, a finding consistent with predictions for Uranus entries. Between 25-30 km/s, radiance is quantified from the Vacuum Ultraviolet through Near Infrared, with focus on the Lyman-alpha and Balmer series lines of Hydrogen. Shock profiles are analyzed for electron number density and electronic state distribution. The shocks do not equilibrate over several cm, and distributions are demonstrated to be non-Boltzmann. Radiation data are compared to simulations of Decadal survey entries for Saturn and shown to be significantly lower than predicted with the Boltzmann radiation model.

  18. Fast E-sail Uranus entry probe mission

    CERN Document Server

    Janhunen, Pekka; Merikallio, Sini; Paton, Mark; Mengali, Giovanni; Quarta, Alessandro A

    2013-01-01

    The solar wind electric sail is a novel propellantless space propulsion concept. According to numerical estimates, the electric sail can produce a large total impulse per propulsion system mass. Here we consider using a 0.5 N electric sail for boosting a 550 kg spacecraft to Uranus in less than 6 years. The spacecraft is a stack consisting of the electric sail module which is jettisoned at Saturn distance, a carrier module and a probe for Uranus atmospheric entry. The carrier module has a chemical propulsion ability for orbital corrections and it uses its antenna for picking up the probe's data transmission and later relaying it to Earth. The scientific output of the mission is similar to what the Galileo Probe did at Jupiter. Measurement of the chemical and isotope composition of the Uranian atmosphere can give key constraints for different formation theories of the solar system. A similar method could also be applied to other giant planets and Titan by using a fleet of more or less identical electric sail e...

  19. DSMC Shock Simulation of Saturn Entry Probe Conditions

    Science.gov (United States)

    Higdon, Kyle J.; Cruden, Brett A.; Brandis, Aaron M.; Liechty, Derek S.; Goldstein, David B.; Varghese, Philip L.

    2016-01-01

    This work describes the direct simulation Monte Carlo (DSMC) investigation of Saturn entry probe scenarios and the influence of non-equilibrium phenomena on Saturn entry conditions. The DSMC simulations coincide with rarefied hypersonic shock tube experiments of a hydrogen-helium mixture performed in the Electric Arc Shock Tube (EAST) at the NASA Ames Research Center. The DSMC simulations are post-processed through the NEQAIR line-by-line radiation code to compare directly to the experimental results. Improved collision cross-sections, inelastic collision parameters, and reaction rates are determined for a high temperature DSMC simulation of a 7-species H2-He mixture and an electronic excitation model is implemented in the DSMC code. Simulation results for 27.8 and 27.4 km/s shock waves are obtained at 0.2 and 0.1 Torr, respectively, and compared to measured spectra in the VUV, UV, visible, and IR ranges. These results confirm the persistence of non-equilibrium for several centimeters behind the shock and the diffusion of atomic hydrogen upstream of the shock wave. Although the magnitude of the radiance did not match experiments and an ionization inductance period was not observed in the simulations, the discrepancies indicated where improvements are needed in the DSMC and NEQAIR models.

  20. Thermal Analysis of Small Re-Entry Probe

    Science.gov (United States)

    Agrawal, Parul; Prabhu, Dinesh K.; Chen, Y. K.

    2012-01-01

    The Small Probe Reentry Investigation for TPS Engineering (SPRITE) concept was developed at NASA Ames Research Center to facilitate arc-jet testing of a fully instrumented prototype probe at flight scale. Besides demonstrating the feasibility of testing a flight-scale model and the capability of an on-board data acquisition system, another objective for this project was to investigate the capability of simulation tools to predict thermal environments of the probe/test article and its interior. This paper focuses on finite-element thermal analyses of the SPRITE probe during the arcjet tests. Several iterations were performed during the early design phase to provide critical design parameters and guidelines for testing. The thermal effects of ablation and pyrolysis were incorporated into the final higher-fidelity modeling approach by coupling the finite-element analyses with a two-dimensional thermal protection materials response code. Model predictions show good agreement with thermocouple data obtained during the arcjet test.

  1. ESA and NASA agree new mission scenario for Cassini-Huygens

    Science.gov (United States)

    2001-07-01

    After six months of investigations and analysis by a joint ESA/NASA Huygens Recovery Task Force (HRTF), senior management from the two space agencies and members of the Cassini-Huygens scientific community have endorsed several modifications to the mission. These will ensure a return close to 100% of the Huygens science data, with no impact on the nominal prime Cassini tour after the third Titan encounter. The modifications have been introduced because of a design flaw in the Huygens communication system. This problem meant that the Huygens receiver was unable to compensate for the frequency shift between the signal emitted by the Probe and the one received by the Orbiter, due to the Doppler shift (**). This would have resulted in the loss of most of the unique data returned from the Probe during its descent through Titan’s dense atmosphere. To ensure that as much data as possible is returned from the pioneering Probe, the HRTF proposed a new schedule for Cassini’s first orbits around Saturn. The agreed scenario involves shortening Cassini’s first two orbits around the ringed planet and adding a third which provides the required new geometry for the Huygens mission to Titan. In the new scenario, the arrival at Saturn on 1 July 2004 remains unchanged. However, Cassini’s first flyby of Titan will now occur on 26 October, followed by another on 13 December. The Huygens Probe will be released towards Titan on 25 December, for an entry into the moon’s atmosphere 22 days later, on 14 January 2005, seven weeks later than originally planned. To reduce the Doppler shift in the signal from Huygens, the Cassini Orbiter will fly over Titan’s cloud tops at a much higher altitude than originally planned - 65,000 km instead of 1,200 km. This higher orbit has the added advantage that Cassini will be able to preserve the four-year baseline tour through the Saturn system, by resuming its original orbital plan in mid-February 2005. “In any complex space mission problems

  2. Encouragement from Jupiter for Europe's Titan Probe

    Science.gov (United States)

    1996-04-01

    remaining after searching reviews of the Probe's design and readiness. Shock tests will check that Huygens is not harmed by the firing of pyrotechnic devices used to release the protective shell and the parachutes, after the Probe's incandescent entry into Titan's atmosphere. In addition, the so-called Titan Test will be repeated. This subjects the Probe to a simulation of the very cold atmosphere of the target moon. A previous test showed some components in Huygens approaching the lower limit of acceptable temperatures. The repeated test will verify that subsequent minor modifications have succeeded in reducing effect of the chilling. Background facts about the Cassini/Huygens mission Huygens is a medium-sized mission of ESA's Horizon 2000 programme for space science, and a contribution to the joint NASA-ESA Cassini mission. Christiaan Huygens discovered Saturn's moon Titan in 1655, and the mission named after him aims to deliver a 343-kilogram Probe to Titan and carry a package of scientific instruments through the atmosphere. Six sets of instruments will analyse the chemical composition of the atmosphere, observe the weather and topography of Titan, and examine the nature of its surface. Titan is larger than the planet Mercury, and its unique atmosphere rich in nitrogen and hydrocarbons may resemble the atmosphere of the primitive Earth, before life began. Nominal dates for the Huygens mission are as follows: - launch, 6 October 1997 - arrival at Saturn, 26 June 2004 - release of Huygens, 6 November 2004 - entry into Titan's atmosphere, 27 November 2004. The Saturn Orbiter, the other element in the Cassini mission, will relay the signals from Huygens to the Earth, before settling down to prolonged observations of Saturn and its rings and moons. European and American scientists are partners in all the experiments, both in the Orbiter and in the Huygens Probe. Farthest out for Europe Huygens will travel to a greater distance from the Sun than any previous ESA mission, out

  3. Cassini-Huygens results on Titan's surface

    Institute of Scientific and Technical Information of China (English)

    Athena Coustenis; Mathieu Hirtzig

    2009-01-01

    Our understanding of Titan, Saturn's largest satellite, has recently been consid-erably enhanced, thanks to the Cassini-Huygens mission. Since the Saturn Orbit Injection in July 2004, the probe has been harvesting new insights of the Kronian system. In par-ticular, this mission orchestrated a climax on January 14, 2005 with the descent of the Huygens probe into Titan's thick atmosphere. The orbiter and the lander have provided us with picturesque views of extraterrestrial landscapes, new in composition but reassuringly Earth-like in shape. Thus, Saturn's largest satellite displays chains of mountains, fields of dark and damp dunes, lakes and possibly geologic activity. As on Earth, landscapes on Titan are eroded and modeled by some alien hydrology: dendritic systems, hydrocarbon lakes, and methane clouds imply periods of heavy rainfalls, even though rain was never observed directly. Titan's surface also proved to be geologically active - today or in the recent past - given the small number of impact craters listed to date, as well as a few possible cryovolcanic features. We attempt hereafter a synthesis of the most significant results of the Cassini-Huygens endeavor, with emphasis on the surface.

  4. Planetary Probe Entry Atmosphere Estimation Using Synthetic Air Data System

    Science.gov (United States)

    Karlgaard, Chris; Schoenenberger, Mark

    2017-01-01

    This paper develops an atmospheric state estimator based on inertial acceleration and angular rate measurements combined with an assumed vehicle aerodynamic model. The approach utilizes the full navigation state of the vehicle (position, velocity, and attitude) to recast the vehicle aerodynamic model to be a function solely of the atmospheric state (density, pressure, and winds). Force and moment measurements are based on vehicle sensed accelerations and angular rates. These measurements are combined with an aerodynamic model and a Kalman-Schmidt filter to estimate the atmospheric conditions. The new method is applied to data from the Mars Science Laboratory mission, which landed the Curiosity rover on the surface of Mars in August 2012. The results of the new estimation algorithm are compared with results from a Flush Air Data Sensing algorithm based on onboard pressure measurements on the vehicle forebody. The comparison indicates that the new proposed estimation method provides estimates consistent with the air data measurements, without the use of pressure measurements. Implications for future missions such as the Mars 2020 entry capsule are described.

  5. Analytical theories for spacecraft entry into planetary atmospheres and design of planetary probes

    Science.gov (United States)

    Saikia, Sarag J.

    This dissertation deals with the development of analytical theories for spacecraft entry into planetary atmospheres and the design of entry spacecraft or probes for planetary science and human exploration missions. Poincare's method of small parameters is used to develop an improved approximate analytical solution for Yaroshevskii's classical planetary entry equation for the ballistic entry of a spacecraft into planetary atmospheres. From this solution, other important expressions are developed including deceleration, stagnation-point heat rate, and stagnation-point integrated heat load. The accuracy of the solution is assessed via numerical integration of the exact equations of motion. The solution is also compared to the classical solutions of Yaroshevskii and Allen and Eggers. The new second-order analytical solution is more accurate than Yaroshevskii's fifth-order solution for a range of shallow (-3 deg) to steep (up to -90 deg) entry flight path angles, thereby extending the range of applicability of the solution as compared to the classical Yaroshevskii solution, which is restricted to an entry flight path of approximately -40 deg. Universal planetary entry equations are used to develop a new analytical theory for ballistic entry of spacecraft for moderate to large initial flight path angles. Chapman's altitude variable is used as the independent variable. Poincare's method of small parameters is used to develop an analytical solution for the velocity and the flight path angle. The new solution is used to formulate key expressions for range, time-of-flight, deceleration, and aerodynamic heating parameters (e.g., stagnation-point heat rate, total stagnation-point heat load, and average heat input). The classical approximate solution of Chapman's entry equation appears as the zero-order term in the new solution. The new solution represents an order of magnitude enhancement in the accuracy compared to existing analytical solutions for moderate to large entry

  6. Europe reaches new frontier - Huygens lands on Titan

    Science.gov (United States)

    2005-01-01

    The first scientific data arrived at the European Space Operations Centre (ESOC) in Darmstadt, Germany, this afternoon at 17:19 CET. Huygens is mankind’s first successful attempt to land a probe on another world in the outer Solar System. “This is a great achievement for Europe and its US partners in this ambitious international endeavour to explore Saturn system,” said Jean-Jacques Dordain, ESA’s Director General. Following its release from the Cassini mothership on 25 December, Huygens reached Titan’s outer atmosphere after 20 days and a 4 million km cruise. The probe started its descent through Titan’s hazy cloud layers from an altitude of about 1270 km at 11:13 CET. During the following three minutes Huygens had to decelerate from 18 000 to 1400 km per hour. A sequence of parachutes then slowed it down to less than 300 km per hour. At a height of about 160 km the probe’s scientific instruments were exposed to Titan’s atmosphere. At about 120 km, the main parachute was replaced by a smaller one to complete the descent, with an expected touchdown at 13:34 CET. Preliminary data indicate that the probe landed safely, likely on a solid surface. The probe began transmitting data to Cassini four minutes into its descent and continued to transmit data after landing at least as long as Cassini was above Titan’s horizon. The certainty that Huygens was alive came already at 11:25 CET today, when the Green Bank radio telescope in West Virginia, USA, picked up a fain but unmistakable radio signal from the probe. Radio telescopes on Earth continued to receive this signal well past the expected lifetime of Huygens. Huygens data, relayed by Cassini, were picked up by NASA’s Deep Space Network and delivered immediately to ESA’s European Space Operation Centre in Darmstadt, Germany, where the scientific analysis is currently taking place. “Titan was always the target in the Saturn system where the need for ‘ground truth’ from a probe was critical. It

  7. Titan from Cassini-Huygens

    CERN Document Server

    Brown, Robert H; Waite, J. Hunter

    2010-01-01

    This book reviews our current knowledge of Saturn's largest moon Titan featuring the latest results obtained by the Cassini-Huygens mission. A global author team addresses Titan’s origin and evolution, internal structure, surface geology, the atmosphere and ionosphere as well as magnetospheric interactions. The book closes with an outlook beyond the Cassini-Huygens mission. Colorfully illustrated, this book will serve as a reference to researchers as well as an introduction for students.

  8. Temperature variations in Titan's upper atmosphere: Impact on Cassini/Huygens

    Directory of Open Access Journals (Sweden)

    B. Kazeminejad

    2005-06-01

    Full Text Available Temperature variations of Titan's upper atmosphere due to the plasma interaction of the satellite with Saturn's magnetosphere and Titan's high altitude monomer haze particles can imply an offset of up to ±30K from currently estimated model profiles. We incorporated these temperature uncertainties as an offset into the recently published Vervack et al. (2004 (Icarus, Vol. 170, 91-112 engineering model and derive extreme case (i.e. minimum and maximum profiles temperature, pressure, and density profiles. We simulated the Huygens probe hypersonic entry trajectory and obtain, as expected, deviations of the probe trajectory for the extreme atmosphere models compared to the simulation based on the nominal one. These deviations are very similar to the ones obtained with the standard Yelle et al. (1997 (ESA SP-1177 profiles. We could confirm that the difference in aerodynamic drag is of an order of magnitude that can be measured by the probe science accelerometer. They represent an important means for the reconstruction of Titan's upper atmospheric properties. Furthermore, we simulated a Cassini low Titan flyby trajectory. No major trajectory deviations were found. The atmospheric torques due to aerodynamic drag, however, are twice as high for our high temperature profile as the ones obtained with the Yelle maximum profile and more than 5 times higher than the worst case estimations from the Cassini project. We propose to use the Cassini atmospheric torque measurements during its low flybys to derive the atmospheric drag and to reconstruct Titan's upper atmosphere density, pressure, and temperature. The results could then be compared to the reconstructed profiles obtained from Huygens probe measurements. This would help to validate the probe measurements and decrease the error bars.

  9. The Huygens Doppler Wind Experiment: Results from Titan

    Science.gov (United States)

    Folkner, W. M.; Bird, M. K.; Dutta-Roy, R.; Allison, M.; Asmar, S. W.; Atkinson, D. H.; Edenhofer, P.; Plettemeier, D.; Tyler, L. H.; Preston, R. A.; Gurvits, L.

    2005-05-01

    The ESA Huygens Probe entered and descended for nearly 2.5 hours through the atmosphere of Titan on 14 January 2005. Huygens survived impact on the surface and continued its telemetry broadcast to the NASA Cassini spacecraft on two separate radio links, denoted Channels A and B, respectively, for an additional 1.2 hours. The instrumentation for the Huygens Doppler Wind Experiment (DWE) consisting of two Ultra-Stable Oscillators in the transmitter (TUSO) and receiver (RUSO), were implemented only in Channel A. Whereas Channel B functioned flawlessly during the entire mission, the receiver for Channel A was never able to lock onto the Huygens signal because the DWE-RUSO had not been properly programmed into the critical probe radio relay sequence. All data on Channel A, including the DWE measurements and probe telemetry, were thus lost. In spite of this setback, the Channel A signal was successfully received at many radio telescopes on Earth. The precision of these Doppler measurements, considered as an aggregate, is roughly equivalent to that which had been foreseen from the measurements on board Cassini. We present an overview of the DWE ground-based observations and the Titan wind profile derived from them.

  10. Cassini at Saturn Huygens results

    CERN Document Server

    Harland, David M

    2007-01-01

    "Cassini At Saturn - Huygens Results" will bring the story of the Cassini-Huygens mission and their joint exploration of the Saturnian system right up to date. Cassini is due to enter orbit around Saturn on the 1 July 2004 and the author will have 8 months of scientific data available for review, including the most spectacular images of Saturn, its rings and satellites ever obtained by a space mission. As the Cassini spacecraft approached its destination in spring 2004, the quality of the images already being returned by the spacecraft clearly demonstrate the spectacular nature of the close-range views that will be obtained. The book will contain a 16-page colour section, comprising a carefully chosen selection of the most stunning images to be released during the spacecraft's initial period of operation. The Huygens craft will be released by Cassini in December 2004 and is due to parachute through the clouds of Saturn's largest moon, Titan, in January 2005.

  11. Saturn from Cassini-Huygens

    CERN Document Server

    Dougherty, Michele K; Krimigis, Stamatios M

    2009-01-01

    This book reviews our current knowledge of Saturn featuring the latest results obtained by the Cassini-Huygens mission. A global author team addresses the planet’s origin and evolution, internal structure, composition and chemistry, the atmosphere and ionosphere, the magnetosphere, as well as its ring system. Furthermore, Saturn's icy satellites are discussed. The book closes with an outlook beyond the Cassini-Huygens mission. Colorfully illustrated, this book will serve as a reference to researchers as well as an introduction for students.

  12. Planetary Formation and Evolution Revealed with a Saturn Entry Probe: The Importance of Noble Gases

    CERN Document Server

    Fortney, Jonathan J; Baraffe, Isabelle; Burrows, Adam; Dodson-Robinson, Sarah E; Chabrier, Gilles; Guillot, Tristan; Helled, Ravit; Hersant, Franck; Hubbard, William B; Lissauer, Jack J; Marley, Mark S

    2009-01-01

    The determination of Saturn's atmospheric noble gas abundances are critical to understanding the formation and evolution of Saturn, and giant planets in general. These measurements can only be performed with an entry probe. A Saturn probe will address whether enhancement in heavy noble gases, as was found in Jupiter, are a general feature of giant planets, and their ratios will be a powerful constraint on how they form. The helium abundance will show the extent to which helium has phase separated from hydrogen in the planet's deep interior. Jupiter's striking neon depletion may also be tied to its helium depletion, and must be confirmed or refuted in Saturn. Together with Jupiter's measured atmospheric helium abundance, a consistent evolutionary theory for both planets, including "helium rain" will be possible. We will then be able to calibrate the theory of the evolution of all giant planets, including exoplanets. In addition, high pressure H/He mixtures under giant planet conditions are an important area of...

  13. Effects of probe shape change on flow phenomena during Jovian entry

    Science.gov (United States)

    Tiwari, S. N.; Subramanian, S. V.

    1979-01-01

    The effects of probe shape change on the flow phenomena around a Jovian entry body is investigated. The initial body shapes considered are: 45-degree sphere cone, 35-degree hyperboloid, and 45-degree ellipsoid. The radiating shock-layer flow is assumed to be axisymmetric, inviscid, and in chemical and local thermodynamic equilibrium. The radiative transfer is calculated with an existing nongray radiation model that accounts for molecular band, atomic line, and continuum transitions. The results indicate that the shock-standoff distance, shock temperature and density, wall pressure distribution and radiative heating to the body are influenced significantly because of the probe shape change. The effect of shape change on radiative heating of the afterbody was considerably larger for the sphere cone and ellipsoid than for the hyperboloid. For the peak heating conditions, the net radiative heating to the body was found to be highest for the ellipsoid

  14. Uncertainty Determination for Aeroheating in Uranus and Saturn Probe Entries by the Monte Carlo Method

    Science.gov (United States)

    Palmer, Grant; Prabhu, Dinesh; Cruden, Brett A.

    2013-01-01

    The 2013-2022 Decaedal survey for planetary exploration has identified probe missions to Uranus and Saturn as high priorities. This work endeavors to examine the uncertainty for determining aeroheating in such entry environments. Representative entry trajectories are constructed using the TRAJ software. Flowfields at selected points on the trajectories are then computed using the Data Parallel Line Relaxation (DPLR) Computational Fluid Dynamics Code. A Monte Carlo study is performed on the DPLR input parameters to determine the uncertainty in the predicted aeroheating, and correlation coefficients are examined to identify which input parameters show the most influence on the uncertainty. A review of the present best practices for input parameters (e.g. transport coefficient and vibrational relaxation time) is also conducted. It is found that the 2(sigma) - uncertainty for heating on Uranus entry is no more than 2.1%, assuming an equilibrium catalytic wall, with the uncertainty being determined primarily by diffusion and H(sub 2) recombination rate within the boundary layer. However, if the wall is assumed to be partially or non-catalytic, this uncertainty may increase to as large as 18%. The catalytic wall model can contribute over 3x change in heat flux and a 20% variation in film coefficient. Therefore, coupled material response/fluid dynamic models are recommended for this problem. It was also found that much of this variability is artificially suppressed when a constant Schmidt number approach is implemented. Because the boundary layer is reacting, it is necessary to employ self-consistent effective binary diffusion to obtain a correct thermal transport solution. For Saturn entries, the 2(sigma) - uncertainty for convective heating was less than 3.7%. The major uncertainty driver was dependent on shock temperature/velocity, changing from boundary layer thermal conductivity to diffusivity and then to shock layer ionization rate as velocity increases. While

  15. Long-life mission reliability for outer planet atmospheric entry probes

    Science.gov (United States)

    Mccall, M. T.; Rouch, L.; Maycock, J. N.

    1976-01-01

    The results of a literature analysis on the effects of prolonged exposure to deep space environment on the properties of outer planet atmospheric entry probe components are presented. Materials considered included elastomers and plastics, pyrotechnic devices, thermal control components, metal springs and electronic components. The rates of degradation of each component were determined and extrapolation techniques were used to predict the effects of exposure for up to eight years to deep space. Pyrotechnic devices were aged under accelerated conditions to an equivalent of eight years in space and functionally tested. Results of the literature analysis of the selected components and testing of the devices indicated that no severe degradation should be expected during an eight year space mission.

  16. Watch Cassini-Huygens setting off for Saturn and Titan

    Science.gov (United States)

    1997-10-01

    NASA's Cassini spacecraft, to which the Italian Space Agency ASI has made an important contribution, is crammed with instruments prepared by American and European scientists. It will spend four busy years in orbit around Saturn, and explore its famous rings and eighteen known moons. On its arrival at Saturn in 2004, the Cassini orbiter will release the European Space Agency's probe Huygens towards the largest moon, Titan.Also equipped by multinational scientific teams, Huygens will parachute through Titan's atmosphere to accomplish the most distant landing ever made, on the surface of another world. Television coverage of the launch for viewers in Europe On Monday 13 October the launch window for Cassini-Huygens opens at 4.55 a.m. Florida time (EDT). Starting at 4.00 a.m. Florida time (10.00 a.m. in most of western Europe and 9.00 a.m. in Great Britain and Ireland) ESA will provide a live TV transmission via satellite for European news organizations and other organizations wishing to receive it. Views of the launch will be accompanied by interviews with scientists and engineers of the Cassini-Huygens joint mission. A short news package will be transmitted near the end of transmission, and details will be announced on air. If the launch occurs promptly, ESA's TV operation will last until about 60 minutes after launch (i.e. about noon, European time). Technical details for TV reception Two satellites links are available, both carrying English on audio channel 1 and French on audio channel 2. Broadcasters and others with digital receivers will favour Intelsat K, while those with analogue receivers can use Eutelsat 2. Full information on transponders etc. is contained in an appendix to this press release. Paris press centre At ESA Headquarters in Paris, journalists will be able to view the TV transmission and to obtain news and background information about the Cassini-Huygens mission. The press centre will open at 10.00 a.m. on 13 October. If you wish to attend, please

  17. Modeling the disequilibrium species for Jupiter and Saturn: Implications for Juno and Saturn entry probe

    Science.gov (United States)

    Wang, D.; Lunine, J. I.; Mousis, O.

    2016-12-01

    Disequilibrium species have been used previously to probe the deep water abundances and the eddy diffusion coefficient for giant planets. In this abstract, we present a diffusion-kinetics code that predicts the abundances of disequilibrium species in the tropospheres of Jupiter and Saturn with updated thermodynamic and kinetic data. The dependence on the deep water abundance and the eddy diffusion coefficient is investigated. We quantified the disagreements in CO kinetics that comes from using different reaction networks and identified C2H6 as a useful tracer for the eddy diffusion coefficient. We first apply an H/P/O reaction network to Jupiter and Saturn's atmospheres and suggest a new PH3 destruction pathway. New chemical pathways for SiH4 and GeH4 destruction are also suggested, and another AsH3 destruction pathway is investigated thanks to new thermodynamic and kinetic data. These new models should enhance the interpretation of the measurement of disequilibrium species by JIRAM on board Juno and allow disentangling between methods for constraining the Saturn's deep water abundance with the Saturn entry probes envisaged by NASA or ESA.

  18. Influence of nonequilibrium radiation on heating of an ablating Jovian entry probe

    Science.gov (United States)

    Tiwari, S. N.; Subramanian, S. V.

    1980-01-01

    The influence of non-local thermodynamic equilibrium (NLTE) radiative transfer on the entire shock-layer flow phenomena around a Jovian entry body is investigated. The flow in the shock layer is assumed to be viscous, axisymmetric, laminar, and in chemical equilibrium. The entry body considered is a 35-deg hyperboloid and the results have been obtained for the peak heating entry conditions. The results indicate that the radiative heating of the entry body is significantly higher under NLTE conditions.

  19. The Cassini-Huygens mission

    CERN Document Server

    The joint NASA-ESA Cassini-Huygens mission promises to return four (and possibly more) years of unparalleled scientific data from the solar system’s most exotic planet, the ringed, gas giant, Saturn. Larger than Galileo with a much greater communication bandwidth, Cassini can accomplish in a single flyby what Galileo returned in a series of passes. Cassini explores the Saturn environment in three dimensions, using gravity assists to climb out of the equatorial plane to look down on the rings from above, to image the aurora and to study polar magnetospheric processes such as field-aligned currents. Since the radiation belt particle fluxes are much more benign than those at Jupiter, Cassini can more safely explore the inner regions of the magnetosphere. The spacecraft approaches the planet closer than Galileo could, and explores the inner moons and the rings much more thoroughly than was possible at Jupiter. This book is the second volume, in a three volume set, that describes the Cassini/Huygens mission. Thi...

  20. Big data en handschriften van Christiaan Huygens

    NARCIS (Netherlands)

    Damen, J.C.M.

    2013-01-01

    In de achtste aflevering van een serie combinatiebesprekingen (digitaalandspeciaal) schenkt Jos Damen aandacht aan een onderzoek naar big data van bibliotheekcatalogi en een catalogus van het werk van het Nederlandse genie Christiaan Huygens.

  1. Radio Telescopes Will Add to Cassini-Huygens Discoveries

    Science.gov (United States)

    2004-12-01

    When the European Space Agency's Huygens spacecraft makes its plunge into the atmosphere of Saturn's moon Titan on January 14, radio telescopes of the National Science Foundation's National Radio Astronomy Observatory (NRAO) will help international teams of scientists extract the maximum possible amount of irreplaceable information from an experiment unique in human history. Huygens is the 700-pound probe that has accompanied the larger Cassini spacecraft on a mission to thoroughly explore Saturn, its rings and its numerous moons. The Green Bank Telescope The Robert C. Byrd Green Bank Telescope CREDIT: NRAO/AUI/NSF (Click on image for GBT gallery) The Robert C. Byrd Green Bank Telescope (GBT) in West Virginia and eight of the ten telescopes of the continent-wide Very Long Baseline Array (VLBA), located at Pie Town and Los Alamos, NM, Fort Davis, TX, North Liberty, IA, Kitt Peak, AZ, Brewster, WA, Owens Valley, CA, and Mauna Kea, HI, will directly receive the faint signal from Huygens during its descent. Along with other radio telescopes in Australia, Japan, and China, the NRAO facilities will add significantly to the information about Titan and its atmosphere that will be gained from the Huygens mission. A European-led team will use the radio telescopes to make extremely precise measurements of the probe's position during its descent, while a U.S.-led team will concentrate on gathering measurements of the probe's descent speed and the direction of its motion. The radio-telescope measurements will provide data vital to gaining a full understanding of the winds that Huygens encounters in Titan's atmosphere. Currently, scientists know little about Titan's winds. Data from the Voyager I spacecraft's 1980 flyby indicated that east-west winds may reach 225 mph or more. North-south winds and possible vertical winds, while probably much weaker, may still be significant. There are competing theoretical models of Titan's winds, and the overall picture is best summarized as

  2. Huygens Atmospheric Structure Instrument (HASI) test by a stratospheric balloon experiment

    Science.gov (United States)

    Fulchignoni, M.; Gaborit, V.; Aboudam, A.; Angrilli, F.; Antonello, M.; Bastianello, S.; Bettanini, C.; Bianchini, G.; Colombatti, G.; Ferri, F.; Lion Stoppato, P.

    2002-09-01

    We developped a series of balloon experiments parachuting a 1:1 scale mock up of the Huygens probe from an altitude larger than 30 km in order to simulate at planetary scale the final part of the descent of the probe in the Titan atmosphere. The Earth atmosphere represents a natural laboratory where most of the physical parameters meet quite well the bulk condition of Titan's environment, with the exception of temperature. A first balloon experiment has been carried out in June 2001 and the results have been reported at the last DPS (V. Gaborit et al., BAAS 33, 38.03) The mock up of the probe descending in the Titan atmosphere for the Huygens Cassini Mission has been successfully launched with stratospheric balloon from Italian Space Agency Base "Luigi Broglio" in Sicily and recovered on May 30th 2002. The probe has been lifted at 32 km altitude and then released to perform a 45 minutes descent decelerated by parachute, to simulate Huygens mission at Titan. Preliminary aerodynamics study of the probe has focused on the achievement of a descent velocity profile and a spin rate profile, satisfying the Huygens mission to Titan requirements. The descent velocity and spin rate have been calculated by solving a system of ODE describing the translational and rotational motion of the probe trough the earth atmosphere during parachute aided descent Results of these calculations have driven the choice of an appropriate angle of attack of the blades in the bottom of the probe and ballast weight during flight. The probe is hosting spares of HASI sensors, housekeeping sensors and other dedicated sensors, Beagle II UV Sensors and Huygens SSP Tilt Sensor, for a total of 77 acquired sensor channels, sampled during ascent, drift and descent phase. Main goals are i) to verify sensor performance and perform a realistic functional test in dynamical and environmental conditions similar to those during the descent in Titan atmosphere; ii) to investigate impact at ground to check the

  3. User's guide for the computer code COLTS for calculating the coupled laminar and turbulent flow over a Jovian entry probe

    Science.gov (United States)

    Kumar, A.; Graeves, R. A.

    1980-06-01

    A user's guide for a computer code 'COLTS' (Coupled Laminar and Turbulent Solutions) is provided which calculates the laminar and turbulent hypersonic flows with radiation and coupled ablation injection past a Jovian entry probe. Time-dependent viscous-shock-layer equations are used to describe the flow field. These equations are solved by an explicit, two-step, time-asymptotic finite-difference method. Eddy viscosity in the turbulent flow is approximated by a two-layer model. In all, 19 chemical species are used to describe the injection of carbon-phenolic ablator in the hydrogen-helium gas mixture. The equilibrium composition of the mixture is determined by a free-energy minimization technique. A detailed frequency dependence of the absorption coefficient for various species is considered to obtain the radiative flux. The code is written for a CDC-CYBER-203 computer and is capable of providing solutions for ablated probe shapes also.

  4. Wind shear and turbulence on Titan: Huygens analysis

    Science.gov (United States)

    Lorenz, Ralph D.

    2017-10-01

    Wind shear measured by Doppler tracking of the Huygens probe is evaluated, and found to be within the range anticipated by pre-flight assessments (namely less than two times the Brunt-Väisälä frequency). The strongest large-scale shear encountered was ∼5 m/s/km, a level associated with 'Light' turbulence in terrestrial aviation. Near-surface winds (below 4 km) have small-scale fluctuations of ∼0.1 m/s on 1 s timescales, indicated both by probe tilt and Doppler tracking, and the characteristics of the fluctuation, of interest for future missions to Titan, can be reproduced with a simple autoregressive (AR(1)) model. The turbulent dissipation rate at an altitude of ∼500 m is found to be ∼0.2 cm2/s3, which may be a useful benchmark for atmospheric circulation models.

  5. Huygens file service and storage architecture

    NARCIS (Netherlands)

    Bosch, Peter; Mullender, Sape; Stabell-Kulo, Tage

    1993-01-01

    The Huygens file server is a high-performance file server which is able to deliver multi-media data in a timely manner while also providing clients with ordinary “Unix” like file I/O. The file server integrates client machines, file servers and tertiary storage servers in the same storage architectu

  6. Huygens file server and storage architecture

    NARCIS (Netherlands)

    Bosch, Peter; Mullender, Sape; Stabell-Kulo, Tage

    1993-01-01

    The Huygens file server is a high-performance file server which is able to deliver multi-media data in a timely manner while also providing clients with ordinary “Unix” like file I/O. The file server integrates client machines, file servers and tertiary storage servers in the same storage architectu

  7. A Fluorescent Probe for Detecting Mycobacterium tuberculosis and Identifying Genes Critical for Cell Entry

    Directory of Open Access Journals (Sweden)

    Dong Yang

    2016-12-01

    Full Text Available ABSTRACTThe conventional method for quantitating Mycobacterium tuberculosis (Mtb in vitro and in vivo relies on bacterial colony forming unit (CFU enumeration on agar plates. Due to the slow growth rate of Mtb, it takes 3-6 weeks to observe visible colonies on agar plates. Imaging technologies that are capable of quickly quantitating both active and dormant tubercle bacilli in vitro and in vivo would accelerate research towards the development of anti-TB chemotherapies and vaccines. We have developed a fluorescent probe that can directly label the Mtb cell wall components. The fluorescent probe, designated as DLF-1, has a strong affinity to the D-Ala-D-Ala unit of the late peptidoglycan intermediates in the bacterial cell wall. We demonstrate that DLF-1 is capable of detecting Mtb in both the active replicating and dormant states in vitro at 100 nM without inhibiting bacterial growth. The DLF-1 fluorescence signal correlated well with CFU of the labeled bacteria (R2=1 and 0.99 for active replicating and dormant Mtb, respectively. DLF-1 can also quantitate labeled Mtb inside of cells. The utility of DLF-1 probe to quantitate Mtb was also successfully applied to identify genes critical for cell invasion. In conclusion, this novel near infrared imaging probe provides a powerful new tool for enumerating Mtb with potential future use in bacterial virulence study.

  8. Modeling the disequilibrium species for Jupiter and Saturn: Implications for Juno and Saturn entry probe

    CERN Document Server

    Wang, Dong; Mousis, Olivier

    2016-01-01

    Disequilibrium species have been used previously to probe the deep water abundances and the eddy diffusion coefficient for giant planets. In this paper, we present a diffusion-kinetics code that predicts the abundances of disequilibrium species in the tropospheres of Jupiter and Saturn with updated thermodynamic and kinetic data. The dependence on the deep water abundance and the eddy diffusion coefficient is investigated. We quantified the disagreements in CO kinetics that comes from using different reaction networks and identified C$_2$H$_6$ as a useful tracer for the eddy diffusion coefficient. We first apply a H/P/O reaction network to Jupiter and Saturn's atmospheres and suggest a new PH$_3$ destruction pathway. New chemical pathways for SiH$_4$ and GeH$_4$ destruction are also suggested, and another AsH$_3$ destruction pathway is investigated thanks to new thermodynamic and kinetic data. These new models should enhance the interpretation of the measurement of disequilibrium species by JIRAM on board Jun...

  9. Digital simulation of a communication link for Pioneer Saturn Uranus atmospheric entry probe, part 1

    Science.gov (United States)

    Hinrichs, C. A.

    1975-01-01

    A digital simulation study is presented for a candidate modulator/demodulator design in an atmospheric scintillation environment with Doppler, Doppler rate, and signal attenuation typical of the conditions of an outer planet atmospheric probe. The simulation results indicate that the mean channel error rate with and without scintillation are similar to theoretical characterizations of the link. The simulation gives information for calculating other channel statistics and generates a quantized symbol stream on magnetic tape from which error correction decoding is analyzed. Results from the magnetic tape data analyses are also included. The receiver and bit synchronizer are modeled in the simulation at the level of hardware component parameters rather than at the loop equation level and individual hardware parameters are identified. The atmospheric scintillation amplitude and phase are modeled independently. Normal and log normal amplitude processes are studied. In each case the scintillations are low pass filtered. The receiver performance is given for a range of signal to noise ratios with and without the effects of scintillation. The performance is reviewed for critical reciever parameter variations.

  10. The Beagle 2 entry descent and landing system (EDLS) software - development and re-use of software for the Red Planet

    Science.gov (United States)

    Symonds, Martin

    2002-07-01

    This paper provides a brief introduction to the Beagle 2 Mars probe and the associated mission, followed by a description of Logica's software responsibility on this programme. The approach taken during software development and implementation of the missioncritical entry, descent and landing system software is then described. This has focussed on maximising re-use of expertise from similar programmes such as Huygens and Rosetta. At the same time effort was devoted to ensure that re-use was enabled within the programme as well as opening up the possibility for re-use on subsequent missions. Finally, the lessons learned are highlighted and a number of conclusions are drawn.

  11. Ongoing Capabilities and Developments of Re-Entry Plasma Ground Tests at EADS-ASTRIUM

    Science.gov (United States)

    Jullien, Pierre

    2008-01-01

    During re-entry, spacecrafts are subjected to extreme thermal loads. On mars, they may go through dust storms. These external heat loads are leading the design of re-entry vehicles or are affecting it for spacecraft facing solid propellant jet stream. Sizing the Thermal Protection System require a good knowledge of such solicitations and means to model and reproduce them on earth. Through its work on European projects, ASTRIUM has developed the full range of competences to deal with such issues. For instance, we have designed and tested the heat-shield of the Huygens probe which landed on Titan. In particular, our plasma generators aim to reproduce a wide variety of re-entry conditions. Heat loads are generated by the huge speed of the probes. Such conditions cannot be fully reproduced. Ground tests focus on reproducing local aerothermal loads by using slower but hotter flows. Our inductive plasma torch enables to test little samples at low TRL. Amongst the arc-jets, one was design to test architecture design of ISS crew return system and others fit more severe re-entry such as sample returns or Venus re-entry. The last developments aimed in testing samples in seeded flows. First step was to design and test the seeding device. Special diagnostics characterizing the resulting flow enabled us to fit it to the requirements.

  12. Christiaan Huygens and the Problem of the Hanging Chain

    Science.gov (United States)

    Bukowski, John F.

    2008-01-01

    The seventeen-year-old Christiaan Huygens was the first to prove that a hanging chain did not take the form of the parabola, as was commonly thought in the early seventeenth century. We will examine Huygen's geometrical proof, and we will investigate the later history of the catenary.

  13. Christiaan Huygens and the Problem of the Hanging Chain

    Science.gov (United States)

    Bukowski, John F.

    2008-01-01

    The seventeen-year-old Christiaan Huygens was the first to prove that a hanging chain did not take the form of the parabola, as was commonly thought in the early seventeenth century. We will examine Huygen's geometrical proof, and we will investigate the later history of the catenary.

  14. Simulation study of communication link for Pioneer Saturn/Uranus atmospheric entry probe. [signal acquisition by candidate modem for radio link

    Science.gov (United States)

    Hinrichs, C. A.

    1974-01-01

    A digital simulation is presented for a candidate modem in a modeled atmospheric scintillation environment with Doppler, Doppler rate, and signal attenuation typical of the radio link conditions for an outer planets atmospheric entry probe. The results indicate that the signal acquisition characteristics and the channel error rate are acceptable for the system requirements of the radio link. The simulation also outputs data for calculating other error statistics and a quantized symbol stream from which error correction decoding can be analyzed.

  15. Atmospheric Entry Experiments at IRS

    Science.gov (United States)

    Auweter-Kurtz, M.; Endlich, P.; Herdrich, G.; Kurtz, H.; Laux, T.; Löhle, S.; Nazina, N.; Pidan, S.

    2002-01-01

    simulations. PHLUX: Based on experiences with PYREX, a sensor for heat flux measurements is being developed at IRS. This experiment is to estimate the dissociation degree during a entry using measured heat fluxes on different catalytic sur- faces. Such information are of importance for the understanding of thermo-chemical relation between plasma and TPS wall. The sensor delivers heat fluxes at wall temperature while most of the existing heat flux measurement systems use heat sink based methodologies meaning that temperatures on these sensors are not the real wall temperatures. Such measurements were planned in the PYREX-KAT38 (X-38) program but had to be set back due to problems with the foreseen catalytic surfaces. Boundary Layer Probe is to determine the boundary layer thickness and pressure. The retractable probe is used to measure the pressure in the flight body boundary layer perpendicular to the material surface. The pressure curve can be used to determine the position and thickness of the shock front. Radiometer: With high enthalpy entries and many interplanetary missions such as missions to Mars or Venus, the radiative portion of the heat flux to a vehicle cannot be neglected. High enthalpy and radiative intensities of some car- bonaceous molecules cause high radiation intensities which is, e.g., the case for the Huygens mission. At IRS, the heat shield material for Huygens was tested and the qualification was carried out. Within this context a radiometer probe for wind tunnel application was developed.

  16. Titan's meridional wind profile and Huygens' orientation and swing inferred from the geometry of DISR imaging

    Science.gov (United States)

    Karkoschka, Erich

    2016-05-01

    The altitude and zonal motion of the Huygens probe descending through Titan's atmosphere was determined early under the assumption of no meridional motion (Bird et al. [2005]. Nature 438, 800-802). By comparing images taken during the descent, Karkoschka et al. (Karkoschka et al. [2007]. Planet. Space Sci. 55, 1895-1935) determined the meridional motion of Huygens, which was generally much smaller than its zonal motion. Here, we present a comprehensive geometrical analysis of all images taken during the descent that is four times more accurate than the previous study. The result is a meridional wind profile across Titan's troposphere with northward winds by up to 0.4 m/s with an average of 0.1 m/s above 1 km altitude, and southward winds below, peaking at 0.9 m/s near 0.4 km altitude. The imaging data extend down to 0.22 km altitude, although additional information came from the horizontal impact speed near 0.8 m/s southward (Schröder et al. [2012]. Planet. Space Sci. 73, 327-340). There is a region between 5 and 8 km altitude with no significant meridional wind. In the stratosphere, the average meridional wind was 1.2 ± 1.5 m/s northward, and zero meridional motion is possible down to 15 km altitude. We present the difference between the zonal speeds of Huygens and the wind that was ignored in previous publications and amounts to up to 7 m/s. We determined the three rotational angles of Huygens for the times of each exposure that showed surface features. During 26 exposures, the swing speed of Huygens was fast enough to smear images. Inferred swing speeds were up to 20°/s during the calm phase of the descent, consistent with up to 40°/s swings reported before during the rough phase. The improved geometric calibration of images allowed identification of many features also seen in Cassini radar images. This comparison yields the location of the Huygens LandingSite as 192.34 ± 02° West and 10.47 ± 0.02° South.

  17. Huygens-Fresnel Principle in Superspace

    CERN Document Server

    de Gomes, H A

    2006-01-01

    We first roughly present a summary of the optico-mechanical analogy, which has always been so profitable in physics. Then we put forward a geometrodynamical formulation of gravity suitable to our intentions, both formally and conceptually. We present difficulties in some approaches to canonically quantize gravity which can be ammended by the idea put forward in this paper, which we introduce in the last section. It consists basically in trying to find an intermediary between the quantization step going from the classical superhamiltonian constraint to the Wheeler-DeWitt equation. This is accomplished by inputing interference beyond the WKB approximation, through a sort of Huygens-Fresnel Principle (HFP) in superspace. It turns out that we can derive wave-like character for both domains from this principle by allowing backward angles of diffraction, and what is more, approximate to a high degree of accuracy Feynman's path integral method in any domain.

  18. Calorimeter probes for measuring high thermal flux. [in electric-arc jet facilities for planetary entry heating simulation

    Science.gov (United States)

    Russell, L. D.

    1979-01-01

    The paper describes expendable, slug-type calorimeter probes developed for measuring high heat-flux levels of 10-30 kW/sq cm in electric-arc jet facilities. The probes are constructed with thin tungsten caps mounted on Teflon bodies; the temperature of the back surface of the tungsten cap is measured, and its rate of change gives the steady-state, absorbed heat flux as the calorimeter probe heats to destruction when inserted into the arc jet. It is concluded that the simple construction of these probes allows them to be expendable and heated to destruction to obtain a measurable temperature slope at high heating rates.

  19. Saturn's Exploration Beyond Cassini-Huygens

    CERN Document Server

    Guillot, Tristan; Charnoz, Sébastien; Dougherty, Michele K; Read, Peter

    2009-01-01

    For its beautiful rings, active atmosphere and mysterious magnetic field, Saturn is a fascinating planet. It also holds some of the keys to understanding the formation of our Solar System and the evolution of giant planets in general. While the exploration by the Cassini-Huygens mission has led to great advances in our understanding of the planet and its moons, it has left us with puzzling questions: What is the bulk composition of the planet? Does it have a helium core? Is it enriched in noble gases like Jupiter? What powers and controls its gigantic storms? We have learned that we can measure an outer magnetic field that is filtered from its non-axisymmetric components, but what is Saturn's inner magnetic field? What are the rings made of and when were they formed? These questions are crucial in several ways: a detailed comparison of the compositions of Jupiter and Saturn is necessary to understand processes at work during the formation of these two planets and of the Solar System. This calls for the contin...

  20. Flow-radiation coupling for atmospheric entries using a Hybrid Statistical Narrow Band model

    Science.gov (United States)

    Soucasse, Laurent; Scoggins, James B.; Rivière, Philippe; Magin, Thierry E.; Soufiani, Anouar

    2016-09-01

    In this study, a Hybrid Statistical Narrow Band (HSNB) model is implemented to make fast and accurate predictions of radiative transfer effects on hypersonic entry flows. The HSNB model combines a Statistical Narrow Band (SNB) model for optically thick molecular systems, a box model for optically thin molecular systems and continua, and a Line-By-Line (LBL) description of atomic radiation. Radiative transfer calculations are coupled to a 1D stagnation-line flow model under thermal and chemical nonequilibrium. Earth entry conditions corresponding to the FIRE 2 experiment, as well as Titan entry conditions corresponding to the Huygens probe, are considered in this work. Thermal nonequilibrium is described by a two temperature model, although non-Boltzmann distributions of electronic levels provided by a Quasi-Steady State model are also considered for radiative transfer. For all the studied configurations, radiative transfer effects on the flow, the plasma chemistry and the total heat flux at the wall are analyzed in detail. The HSNB model is shown to reproduce LBL results with an accuracy better than 5% and a speed up of the computational time around two orders of magnitude. Concerning molecular radiation, the HSNB model provides a significant improvement in accuracy compared to the Smeared-Rotational-Band model, especially for Titan entries dominated by optically thick CN radiation.

  1. Pioneer Jupiter orbiter probe mission 1980, probe description

    Science.gov (United States)

    Defrees, R. E.

    1974-01-01

    The adaptation of the Saturn-Uranus Atmospheric Entry Probe (SUAEP) to a Jupiter entry probe is summarized. This report is extracted from a comprehensive study of Jovian missions, atmospheric model definitions and probe subsystem alternatives.

  2. How to handle a Huygens' box inside an enclosure

    DEFF Research Database (Denmark)

    Sørensen, Morten; Bonev, Ivan Bonev; Franek, Ondrej;

    2013-01-01

    It has been suggested that it is possible to replace printed circuit boards with a Huygens' box (HB) representation obtained from a near-field scan in simulation of far-fields from an apparatus. However, the surface equivalence theorem requires that the environment outside HB is the same in the n......It has been suggested that it is possible to replace printed circuit boards with a Huygens' box (HB) representation obtained from a near-field scan in simulation of far-fields from an apparatus. However, the surface equivalence theorem requires that the environment outside HB is the same...

  3. Photochemical enrichment of deuterium in Titan's atmosphere: new insights from Cassini-Huygens

    CERN Document Server

    Cordier, D; Lunine, I J; Moudens, A; Vuitton, V

    2008-01-01

    Cassini-Huygens data are used to re-examine the potential sources of the D/H enhancement over solar, measured in methane, in Titan's atmosphere. Assuming that the system is closed with respect to carbon, the use of constraints from the Huygens probe for the determination of the current mass of atmospheric methane and the most up-to-date determination of D/H from Cassini/CIRS infrared spectra allow us to show that photochemical enrichment of deuterium is not sufficient to be the sole mechanism yielding the measured D/H value. A possible fractionation between CH3D and CH4 during the escape process may slightly enhance the deuterium enrichment, but is not sufficient to explain the observed D/H value over the range of escape values proposed in the literature. Hence, alternative mechanisms such as a primordial deuterium enrichment must be combined with the photochemical enrichment in Titan's atmosphere in order to explain its current D/H value.

  4. Titan en Christiaan. Huygens in werk en leven

    NARCIS (Netherlands)

    Dijksterhuis, Fokko J.

    2000-01-01

    In three respects Christiaan Huygens (1629-1695) poses a biographical problem. Unlike contemporaries he hardly ever reflected upon what he thought he was doing; his versatility makes it hard to gain a balanced view of what he was doing; his personality seems almost absent from his writings. In the

  5. Titan's interior from Cassini-Huygens

    Science.gov (United States)

    Tobie, G.; Baland, R.-M.; Lefevre, A.; Monteux, J.; Cadek, O.; Choblet, G.; Mitri, G.

    2013-09-01

    The Cassini-Huygens mission has brought many informations about Titan that can be used to infer its interior structure: the gravity field coefficients (up to degree 3, [1]), the surface shape (up to degree 6, [2]), the tidal Love number [1], the electric field [3], and the orientation of its rotation axis [4]. The measured obliquity and gravity perturbation due to tides, as well as the electric field, are lines of evidence for the presence of an internal global ocean beneath the ice surface of Titan [5,1,3]. The observed surface shape and gravity can be used to further constrain the structure of the ice shell above the internal ocean. The presence of a significant topography associated with weak gravity anomalies indicates that deflections of internal interface or lateral density variations may exist to compensate the topography. To assess the sources of compensation, we consider interior models including interface deflections and/or density variations, which reproduces simultaneously the surface gravity and long-wavelength topography data [6]. Furthermore, in order to test the long-term mechanical stability of the internal mass anomalies, we compute the relaxation rate of each internal interface in response to surface mass load. We show that the topography can be explained either by defections of the ocean/ice interface or by density variations in an upper crust [6]. For non-perfectly compensated models of the outer ice shell, the present-day structure is stable only for a conductive layer above a relatively cold ocean (for bottom viscosity > 1016 Pa.s, T Love number and the obliquity. To derive the possible density profile, the obliquity is computed from a Cassini state model for a satellite with an internal liquid layer, each layer having an ellipsoidal shape consistent with the measured surface shape and gravity field [7]. We show that, once the observed surface flattening is taken into account, the measured obliquity can be reproduced only for internal models

  6. Titan Ground Complex Permittivity at the HUYGENS Landing Site; the PWA-HASI and Other Instruments Data Revisited

    Science.gov (United States)

    Hamelin, M.; Lethuillier, A.; Le Gall, A. A.; Grard, R.; Ciarletti, V.; Béghin, C.; Schwingenschuh, K.; Lorenz, R. D.; Lopez-Moreno, J. J.; Jernej, I.; Brown, V.; Ferri, F.

    2014-12-01

    Ten years after the successful landing of the HUYGENS probe on the surface of Titan, we reassess the complex permittivity measurements of the surface materials performed by the PWA-HASI experiment (Permittivity, Waves and Altimetry - Huygens Atmospheric Structure Instrument). The complex permittivity is inferred from the mutual impedance of a classical quadrupolar probe, ie. the ratio of the voltage measured by a receiving dipole over the current emitted by another dipole. Using a simple model of the quadrupole configuration, the dielectric constant of the material at the landing site was first estimated to be of the order of 1.8. A more realistic numerical model that took into account the influence of the HUYGENS gondola yielded a dielectric constant in the range 2-3 and a conductivity in the range 0.4 - 0.8 nS/m. due to uncertainties about the system geometry ( Grard et al., 2006). However, a puzzling experimental fact remains to be explained, namely a sudden variation of the amplitude and phase of the received voltage 11 mn after landing that cannot be associated with any lander mechanical disturbance. Permittivity estimations were based on the first 11 mn sequence. The present analysis takes advantage of a recent analysis of the landing process that provided more realistic final position and attitude for the HUYGENS lander (Schroder et al., 2012). The new results lie within former estimated ranges and attention is paid to their sensitivity to geometry and to the reference measurements collected immediately before landing. This point is particularly critical for the estimation of the conductivity. The complete data set has been analysed, including the sequence collected after the first 11 mn. We consider various scenarios that may explain the observed phase and amplitude discontinuity. We tested two layers ground models in order to investigate the possibility that the upper layer may have experienced a fast physical change due to deliquescence or outgasing

  7. Teaching Huygens in the Rue Huygens: Introducing the History of 17th-Century Mathematics in a Junior Secondary School.

    Science.gov (United States)

    Hallez, Maryvonne

    1992-01-01

    Recounts teaching mathematics to junior high school students in France in the context of seventeenth-century mathematics history. Examines extracts of original works by Leibniz on the origin of calculus and of Huygens on continued fractions. Investigates historical puzzles and a variety of mathematical problems arising out of the texts. (MDH)

  8. Analytical pyrolysis experiments of Titan aerosol analogues in preparation for the Cassini Huygens mission

    Science.gov (United States)

    Ehrenfreund, P.; Boon, J. J.; Commandeur, J.; Sagan, C.; Thompson, W. R.; Khare, B.

    1995-01-01

    Comparative pyrolysis mass spectrometric data of Titan aerosol analogs, called 'tholins', are presented. The Titan tholins were produced in the laboratory at Cornell by irradiation of simulated Titan atmospheres with high energy electrons in plasma discharge. Mass-spectrometry measurements were performed at FOM of the solid phase of various tholins by Curie-point pyrolysis Gas-Chromatography/Mass-Spectrometry (GCMS) and by temperature resolved in-source Pyrolysis Mass-Spectrometry to reveal the composition and evolution temperature of the dissociation products. The results presented here are used to further define the ACP (Aerosol Collector Pyrolyser)-GCMS experiment and provide a basis for modelling of aerosol composition on Titan and for the iterpretation of Titan atmosphere data from the Huygens probe in the future.

  9. Huygens Crater: Insights into Noachian Volcanism, Stratigraphy, and Aqueous Processes

    Science.gov (United States)

    Ackiss, S. E.; Wray, J. J.; Seelos, K. D.; Niles, P. B.

    2015-01-01

    Huygens crater is a well preserved peak ring structure on Mars centered at 13.5 deg S, 55.5 deg E in the Noachian highlands between Terras Tyrrhena and Sabaea near the NW rim of Hellas basin. With a diameter of approximately 470 km, it uplifted and exhumed pre-Noachian crustal materials from depths greater than 25 km, penetrating below the thick, ubiquitous layer of Hellas ejecta. In addition, Huygens served as a basin for subsequent aqueous activity, including erosion/deposition by fluvial valley networks and subsurface alteration that is now exposed by smaller impacts. Younger mafic-bearing plains that partially cover the basin floor and surrounding intercrater areas were likely emplaced by later volcanism.

  10. Shock tube spectroscopy of C3 + C2H mixture in the 140 to 700 nm range. [for Jovian entry probe ablation layer simulation

    Science.gov (United States)

    Prakash, S. G.; Park, C.

    1979-01-01

    Absorption spectroscopy has been performed in the reflected-shock region of a shock tube. Acetylene was shock-heated to produce a mixture, at around 4000 K, rich in C3 and C2H to simulate the ablation layer over the Jovian entry probe, and the spectral range from 140 to 700 nm was surveyed with an evacuable spectrograph. The observed spectra were dominated by those of C2 and C3 and an unknown band at wavelengths below 300 nm. The cross sections of the C3 Swings band in the 300 to 450 nm range agreed with previous measurements within a factor of 1.5. No absorption was observed in the wavelength range from 550 to 700 nm. The unknown broadband absorption with a peak cross section of 4 times 10 to the minus 17/sq cm at around 170 nm was attributed tentatively to the C2H radical. A preliminary calculation showed that the newly found absorption band would reduce the radiative heat flux to the stagnation point wall by about 12.5% in a typical flight condition.

  11. On Huygens' principle for Dirac operators associated to electromagnetic fields

    Directory of Open Access Journals (Sweden)

    CHALUB FABIO A.C.C.

    2001-01-01

    Full Text Available We study the behavior of massless Dirac particles, i.e., solutions of the Dirac equation with m = 0 in the presence of an electromagnetic field. Our main result (Theorem 1 is that for purely real or imaginary fields any Huygens type (in Hadamard's sense Dirac operators is equivalent to the free Dirac operator, equivalence given by changes of variables and multiplication (right and left by nonzero functions.

  12. Generalized Huygens principle with pulsed-beam wavelets

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Thorkild [Seknion Inc., Boston, MA (United States); Kaiser, Gerald [Signals and Waves, Austin, TX (United States)], E-mail: thorkild.hansen@att.net, E-mail: kaiser@wavelets.com

    2009-11-27

    Huygens' geometric construction explaining wave motion has a well-known problem with unphysical back-propagation due to the spherical nature of the secondary wavelets. We solve this by analytically continuing the surface of integration. If the surface is a sphere S{sub R} of radius R, this is done by complexifying R to {alpha} = R + ia. The resulting complex sphere S{sub {alpha}} is shown to be equivalent to the real tangent disk bundle with base S{sub R} consisting of all disks with radius a tangent to S{sub R}. Huygens' secondary source points are thus replaced by disks, and his secondary wavelets by well-focused pulsed beams propagating outward. This solves the back-propagation problem. The generalized Huygens principle is a completeness relation for these pulsed-beam wavelets enabling a pulsed-beam representation of all radiation fields. Furthermore, this yields a natural and extremely efficient way to compute radiation fields numerically because all pulsed beams missing a given observer can be ignored with minimal error. Increasing the disk radius a sharpens the focus of the pulsed beams, which in turn raises the compression ratio of the representation.

  13. Lenses and waves Christiaan Huygens and the mathematical science of optics in the seventeenth century

    CERN Document Server

    Dijksterhuis, Fokko Jan

    2004-01-01

    In 1690, Christiaan Huygens (1629-1695) published Traité de la Lumière, containing his renowned wave theory of light. It is considered a landmark in seventeenth-century science, for the way Huygens mathematized the corpuscular nature of light and his probabilistic conception of natural knowledge. This book discusses the development of Huygens' wave theory, reconstructing the winding road that eventually led to Traité de la Lumière. For the first time, the full range of manuscript sources is taken into account. In addition, the development of Huygens' thinking on the nature of light is put in t

  14. Cassini-Huygens Ion Neutral Mass Spectrometer and the Future

    Science.gov (United States)

    Waite, J. Hunter

    2014-05-01

    The Cassini-Huygens Ion Neutral Mass Spectrometer (Cassini INMS) designed and built by Hasso Niemann has revolutionized our understanding of the Saturn system and demonstrated the importance of mass spectrometry as a tool for understanding formation, evolution, and chemical processes. In this talk that honors the accomplishments of Hasso I will discuss: 1) the major discoveries of INMS at Titan, Enceladus, and the other icy moons of Saturn, 2) the new perspective this has given us on understanding the formation and evolution of the outer solar system, and 3) the implications for future studies in the outer solar system using mass spectrometry.

  15. Lenses and Waves - Christiaan Huygens and the Mathematical Science of Optics in the Seventeenth Century

    NARCIS (Netherlands)

    Dijksterhuis, Fokko J.

    2004-01-01

    In 1690, Christiaan Huygens (1629-1695) published Traité de la Lumière, containing his renowned wave theory of light. It is considered a landmark in seventeenth-century science, for the way Huygens mathematized the corpuscular nature of light and his probabilistic conception of nature knowledge.

  16. Estimation of Radiation Limit from a Huygens' Box under Non-Free-Space Conditions

    DEFF Research Database (Denmark)

    Franek, Ondrej; Sørensen, Morten; Bonev, Ivan Bonev

    2013-01-01

    The recently studied Huygens' box method has difficulties when radiation of an electronic module is to be determined under non-free-space conditions, i.e. with an enclosure. We propose an estimate on radiation limit under such conditions based only on the Huygens' box data from free...

  17. Exact Finite-Difference Time-Domain Modelling of Broadband Huygens' Metasurfaces with Lorentz Dispersions

    CERN Document Server

    Smy, Tom J

    2016-01-01

    An explicit time-domain finite-difference technique for modelling zero-thickness Huygens' metasurfaces based on Generalized Sheet Transition Conditions (GSTCs), is proposed and demonstrated using full-wave simulations. The Huygens' metasurface is modelled using electric and magnetic surface susceptibilities, which are found to follow a double-Lorentz dispersion profile. To solve zero-thickness Huygens' metasurface problems for general broadband excitations, the double-Lorentz dispersion profile is combined with GSTCs, leading to a set of first-order differential fields equations in time-domain. Identifying the exact equivalence between Huygens' metasurfaces and coupled RLC oscillator circuits, the field equations are then subsequently solved using standard circuit modelling techniques based on a finite-difference formulation. Several examples including generalized refraction are shown to illustrate the temporal evolution of scattered fields from the Huygens' metasurface under plane-wave normal incidence, in b...

  18. Discontinuous Electromagnetic Fields Using Huygens Sources For Wavefront Manipulation

    CERN Document Server

    Selvanayagam, Michael

    2013-01-01

    We introduce the idea of discontinuous electric and magnetic fields at a boundary to design and shape wavefronts in an arbitrary manner. To create this discontinuity in the field we use electric and magnetic currents which act like a Huygens source to radiate the desired wavefront. These currents can be synthesized either by an array of electric and magnetic dipoles or by a combined impedance and admittance surface. A dipole array is an active implementation to impose discontinuous fields while the impedance/admittance surface acts as a passive one. We then expand on our previous work showing how electric and magnetic dipole arrays can be used to cloak an object demonstrating two novel cloaking schemes. We also show how to arbitrarily refract a beam using a set of impedance and admittance surfaces. Refraction using the idea of discontinuous fields is shown to be a more general case of refraction using phase discontinuities.

  19. Strong terahertz absorption in all-dielectric Huygens' metasurfaces.

    Science.gov (United States)

    Cole, Michael A; Powell, David A; Shadrivov, Ilya V

    2016-09-19

    We propose an all dielectric metamaterial that acts as a perfect terahertz absorber without a ground plane. The unit cell consists of a dielectric cylinder embedded in a low index material. In order to achieve near-perfect terahertz absorption (99.5%) we employ impedance matching of the electric and magnetic resonances within the cylinders of the Huygens' metasurface. The impedance matching is controlled by changing the aspect ratio between the height and diameter of the cylinder. We show that the absorption resonance can be tuned to particular frequencies from 0.3 to 1.9 THz via changing the geometry of the structure while keeping a nearly constant aspect ratio of the cylinders.

  20. Chiral Huygens metasurfaces for nonlinear structuring of linearly polarized light

    CERN Document Server

    Lesina, A Calà; Ramunno, L

    2016-01-01

    We report on a chiral nanostructure, which we term a "butterfly nanoantenna," that, when used in a metasurface, allows the direct conversion of a linearly polarized beam into a nonlinear optical far-field of arbitrary complexity. The butterfly nanoantenna exhibits field enhancement in its gap for every incident linear polarization, which can be exploited to drive nonlinear optical emitters within the gap, for the structuring of light within a frequency range not accessible by linear plasmonics. As the polarization, phase and amplitude of the field in the gap are highly controlled, nonlinear emitters within the gap behave as an idealized Huygens source. A general framework is thereby proposed wherein the butterfly nanoantennas can be arranged on a surface to produce a highly structured far-field nonlinear optical beam with high purity. A third harmonic Laguerre-Gauss beam carrying an optical orbital angular momentum of 41 is demonstrated as an example, through large-scale simulations on a high-performance comp...

  1. Huygens landing site to be named after Hubert Curien

    Science.gov (United States)

    2007-03-01

    The naming ceremony for the Huygens landing site, which will be known as the "Hubert Curien Memorial Station", will be held at ESA’s Headquarters on 14 March, in the presence of ESA Council delegates and of Professor Curien’s wife, Mrs Perrine Curien, and one of their sons. Media interested in attending are invited to submit the reply form below. Huygens' landing on Saturn’s largest moon in January 2005 represented one of the greatest successes achieved by humankind in the history of space exploration. The part played by ESA, in cooperation with NASA and the Italian Space Agency (ASI), was made possible thanks to the commitment of a man who, for several decades, worked to promote and strengthen the role of scientific research in his home country - France - and in Europe. Among his numerous responsibilities, Hubert Curien was French Minister of Research and Space under four Prime Ministers. As Chairman of the ESA Council from 1981 to 1984, Professor Curien played a crucial part in setting up ESA's former long-term science programme, "Horizon 2000", which included the Huygens mission among its projects. Professor Roger Bonnet, current President of COSPAR, and former ESA Director of Science (1983-2001), commented: "Curien’s diplomatic skills were hugely influential in bringing about the birth of European space science. In 1985, his support was pivotal when the European ministers had to decide how to build a solid space science programme and ensure that it would be financially sustainable in the long term." "ESA's present science programme, Cosmic Vision, draws on the heritage left by Hubert Curien", said Professor David Southwood, ESA's current Director of Science. "He encouraged cooperation between nations in the belief that space research is fundamental to the progress and welfare of a knowledge-based society like ours. He also promoted the concept of long-term planning", he continued. "It would seem almost inconceivable today to initiate any space venture

  2. Efficient polarization insensitive complex wavefront control using Huygens' metasurfaces based on dielectric resonant meta-atoms

    CERN Document Server

    Chong, Katie E; Staude, Isabelle; James, Anthony; Dominguez, Jason; Liu, Sheng; Subramania, Ganapathi S; Decker, Manuel; Neshev, Dragomir N; Brener, Igal; Kivshar, Yuri S

    2016-01-01

    Subwavelength-thin metasurfaces have shown great promises for the control of optical wavefronts, thus opening new pathways for the development of efficient flat optics. In particular, Huygens' metasurfaces based on all-dielectric resonant meta-atoms have already shown a huge potential for practical applications with their polarization insensitivity and high transmittance efficiency. Here, we experimentally demonstrate a polarization insensitive holographic Huygens' metasurface based on dielectric resonant meta-atoms capable of complex wavefront control at telecom wavelengths. Our metasurface produces a hologram image in the far-field with 82% transmittance efficiency and 40% imaging efficiency. Such efficient complex wavefront control shows that Huygens' metasurfaces based on resonant dielectric meta-atoms are a big step towards practical applications of metasurfaces in wavefront design related technologies, including computer-generated holograms, ultra-thin optics, security and data storage devices.

  3. On the Huygens principle for bianisotropic mediums with symmetric permittivity and permeability dyadics

    Science.gov (United States)

    Faryad, Muhammad; Lakhtakia, Akhlesh

    2017-02-01

    Mathematical statements of the Huygens principle relate the electric and magnetic field phasors at an arbitrary location in a source-free region enclosed by a surface to the tangential components of the electric and magnetic field phasors over that surface, via the dyadic Green functions applicable to the linear homogeneous medium occupying that region. We have mathematically formulated the Huygens principle for the electric and magnetic field phasors when the permittivity and permeability dyadics of the medium are symmetric, the symmetric parts of the two magnetoelectric dyadics of the medium are negative of each other, and both magnetoelectric dyadics also contain anti-symmetric terms. We have also formulated the Huygens principle for the electric (resp. magnetic) field phasor in a medium whose permittivity (resp. permeability) is scalar, the permeability (resp. permittivity) is symmetric, the symmetric parts of the two magnetoelectric dyadics reduce to dissimilar scalars, and anti-symmetric parts of the two magnetoelectric dyadics are identical.

  4. High-efficiency light-wave control with all-dielectric optical Huygens' metasurfaces

    CERN Document Server

    Decker, Manuel; Falkner, Matthias; Dominguez, Jason; Neshev, Dragomir N; Brener, Igal; Pertsch, Thomas; Kivshar, Yuri S

    2014-01-01

    Optical metasurfaces have developed as a breakthrough concept for advanced wave-front engineering enabled by subwavelength resonant nanostructures. However, reflection and/or absorption losses as well as low polarisation-conversion efficiencies pose a fundamental obstacle for achieving high transmission efficiencies that are required for practical applications. Here we demonstrate, for the first time to our knowledge, highly efficient all-dielectric metasurfaces for near-infrared frequencies using arrays of silicon nanodisks as meta-atoms. We employ the main features of Huygens' sources, namely spectrally overlapping electric and magnetic dipole resonances of equal strength, to demonstrate Huygens' metasurfaces with a full transmission-phase coverage of 360 degrees and near-unity transmission, and we confirm experimentally full phase coverage combined with high efficiency in transmission. Based on these key properties, we show that all-dielectric Huygens' metasurfaces could become a new paradigm for flat opti...

  5. Twenty Years of Systems Engineering on the Cassini-Huygens Mission

    Science.gov (United States)

    Manor-Chapman, Emily

    2013-01-01

    Over the past twenty years, the Cassini-Huygens Mission has successfully utilized systems engineering to develop and execute a challenging prime mission and two mission extensions. Systems engineering was not only essential in designing the mission, but as knowledge of the system was gained during cruise and science operations, it was critical in evolving operational strategies and processes. This paper discusses systems engineering successes, challenges, and lessons learned on the Cassini-Huygens Mission gathered from a thorough study of mission plans and developed scenarios, and interviews with key project leaders across its twenty-year history.

  6. Huygens' principle, the free Schrodinger particle and the quantum anti-centrifugal force

    DEFF Research Database (Denmark)

    Cirone, M.A.; Dahl, Jens Peder; Fedorov, M.

    2002-01-01

    Huygens' principle following from the d'Alembert wave equation is not valid in two-dimensional space. A Schrodinger particle of vanishing angular momentum moving freely in two dimensions experiences an attractive force-the quantum anti-centrifugal force-towards its centre. We connect these two...

  7. Huygens-Feynman-Fresnel principle as the basis of applied optics.

    Science.gov (United States)

    Gitin, Andrey V

    2013-11-01

    The main relationships of wave optics are derived from a combination of the Huygens-Fresnel principle and the Feynman integral over all paths. The stationary-phase approximation of the wave relations gives the correspondent relations from the point of view of geometrical optics.

  8. Influence of nearby obstacles on the feasibility of a Huygens box as a field source

    DEFF Research Database (Denmark)

    Franek, Ondrej; Sørensen, Morten; Ebert, Hans;

    2012-01-01

    A method of substituting an electronic module with its Huygens box representation for the purpose of calculating the emitted field is discussed. It is pointed out that nearby obstacles may have harmful effect on the accuracy of such method. This is subsequently proven by performing finite-differe...

  9. Violation of the strong Huygen's principle and timelike signals from the early universe.

    Science.gov (United States)

    Blasco, Ana; Garay, Luis J; Martín-Benito, Mercedes; Martín-Martínez, Eduardo

    2015-04-10

    We analyze the implications of the violations of the strong Huygen's principle in the transmission of information from the early Universe to the current era via massless fields. We show that much more information reaches us through timelike channels (not mediated by real photons) than is carried by rays of light, which are usually regarded as the only carriers of information.

  10. Huygens' principle, the free Schrodinger particle and the quantum anti-centrifugal force

    DEFF Research Database (Denmark)

    Cirone, M.A.; Dahl, Jens Peder; Fedorov, M.

    2002-01-01

    Huygens' principle following from the d'Alembert wave equation is not valid in two-dimensional space. A Schrodinger particle of vanishing angular momentum moving freely in two dimensions experiences an attractive force-the quantum anti-centrifugal force-towards its centre. We connect these two ph...

  11. US Ports of Entry

    Data.gov (United States)

    Department of Homeland Security — HSIP Non-Crossing Ports-of-Entry A Port of Entry is any designated place at which a CBP officer is authorized to accept entries of merchandise to collect duties, and...

  12. O tratado sobre a luz de Huygens: comentários

    OpenAIRE

    Krapas, Sonia; Departamento de Física – UFF Niterói – RJ; Queiroz, Glória Regina Pessôa Campello; Instituto de Física - UERJ Rio de Janeiro – RJ; Uzêda, Diego; Instituto de Ciências e Tecnologia Maria Thereza – FAMATh Niterói – RJ

    2011-01-01

    http://dx.doi.org/10.5007/2175-7941.2011v28n1p123Huygens é conhecido no ensino introdutório de Física por dar conta da refração segundo um modelo ondulatório. Livros didáticos lhe rendem homenagens atribuindo seu nome a um princípio, mas em sua obra máxima, Tratado sobre a luz, é possível se ver muito mais: sua inventividade na defesa de um modelo ondulatório para a luz como alternativo ao modelo corpuscular. Neste trabalho, tenta-se evidenciar o raciocínio de Huygens, mostrando que, apesar d...

  13. Highly-efficient all-dielectric Huygens' surface holograms (Conference Presentation)

    Science.gov (United States)

    Chong, Katie; Wang, Lei; Staude, Isabelle; James, Anthony; Dominguez, Jason; Subramania, Ganapathi; Liu, Sheng; Decker, Manuel; Neshev, Dragomir N.; Brener, Igal; Kivshar, Yuri S.

    2016-04-01

    Optical metasurfaces have developed as a breakthrough concept for advanced wave-front. Key to these "designer metasurfaces"[1] is that they provide full 360 degree phase coverage and that their local phase can be precisely controlled. The local control of phase, amplitude and polarization on an optically thin plane will lead to a new class of flat optical components in the areas of integrated optics, flat displays, energy harvesting and mid-infrared photonics, with increased performance and functionality. However, reflection and/or absorption losses as well as low polarization-conversion efficiencies pose a fundamental obstacle for achieving high transmission efficiencies that are required for practical applications. A promising way to overcome these limitations is the use of metamaterial Huygens' surfaces [2-4], i.e., reflection-less surfaces that can also provide full 360 degree phase coverage in transmission. Plasmonic implementations of Huygens' surfaces for microwave [2] and the mid-infrared spectral range [3], where the intrinsic losses of the metals are negligible, have been suggested, however, these designs cannot be transferred to near-infrared or even visible frequencies because of the high dissipative losses of plasmonic structures at optical frequencies. Here, we demonstrate the first holographic metasurface utilizing the concept of all-dielectric Huygens' surfaces thereby achieving record transmission efficiencies of approximately 82% at 1477nm wavelength. Our low-loss Huygens' surface is realized by two-dimensional subwavelength arrays of loss-less silicon nanodisks with both electric and magnetic dipole resonances [4]. By controlling the intrinsic properties of the resonances, i.e. their relative electric and magnetic polarizabilities, quality factors and spectral position, we can design silicon nanodisks to behave as near-ideal Huygens' particles. This allows us to realize all-dielectric Huygens' surfaces providing full 360 degree phase coverage

  14. A Huygens Surface Approach to Antenna Implementation in Near-Field Radar Imaging System Simulations

    Science.gov (United States)

    2015-08-01

    critical geometrical details; re- casting the FDTD update equations on a grid conformal to a curvilinear coordinate system (e.g., cylindrical); and...Imaging System Simulations by Traian Dogaru and DaHan Liao Approved for public release; distribution unlimited...A Huygens Surface Approach to Antenna Implementation in Near-Field Radar Imaging System Simulations by Traian Dogaru and DaHan Liao Sensors

  15. Huygens-Fresnel principle for N-photon states of light

    OpenAIRE

    2010-01-01

    We show that the propagation of a N-photon field in space and time can be described by a generalized Huygens-Fresnel integral. Using two examples, we then demonstrate how familiar Fourier optics techniques applied to a N-photon wave function can be used to engineer the propagation of entanglement and to design the way the detection of one photon shapes the state of the others.

  16. Planetary/DOD entry technology flight experiments. Volume 2: Planetary entry flight experiments

    Science.gov (United States)

    Christensen, H. E.; Krieger, R. J.; Mcneilly, W. R.; Vetter, H. C.

    1976-01-01

    The technical feasibility of launching a high speed, earth entry vehicle from the space shuttle to advance technology for the exploration of the outer planets' atmospheres was established. Disciplines of thermodynamics, orbital mechanics, aerodynamics propulsion, structures, design, electronics and system integration focused on the goal of producing outer planet environments on a probe shaped vehicle during an earth entry. Major aspects of analysis and vehicle design studied include: planetary environments, earth entry environment capability, mission maneuvers, capabilities of shuttle upper stages, a comparison of earth entry planetary environments, experiment design and vehicle design.

  17. Framing Space: UK Newspaper Reporting of the Beagle 2 and Cassini-Huygens Space Missions

    Science.gov (United States)

    Jergovic, B.; Miller, S.

    2008-05-01

    Relatively little scholarly work has been done on looking at the portrayal of astronomy and space science in the media. This short article examines the UK press coverage of two space missions: the Beagle 2 mission to Mars and the Cassini-Huygens mission to Saturn and its moon Titan. In both cases, the leading scientists exerted a strong influence on what journalists reported, to the extent that some journalists appeared to be almost "embedded" in the mission. For the most part the coverage is positive in tone and the loss of the Beagle 2 spacecraft does not reflect badly on the (later) Cassini-Huygens coverage. Most journalists only covered the actual mission events and, in the case of Huygens, did not follow up to cover the peer-reviewed scientific articles that appeared later. Off-the-cuff comments made by scientists at the time of the missions were widely reported. There appears to be an appreciation by journalists and (by inference) their readership that this was science in the making, and that allowances should be made if these comments later turned out to be inaccurate.

  18. Optical properties of Titan's aerosols: comparison between DISR/Huygens observations and VIMS/Cassini solar occultation observations

    Science.gov (United States)

    Marmuse, Florian; Sotin, Christophe; Lawrence, Kenneth J.; Brown, Robert H.; Baines, Kevin; Buratti, Bonnie; Clark, Roger Nelson; Nicholson, Philip D.

    2016-10-01

    Titan, the only satellite with a dense atmosphere, presents a hydrocarbon cycle that includes the formation and sedimentation of organic aerosols. The optical properties of Titan's haze inferred from measurement of the Huygens probe were recently revisited by Doose et al. (Icarus, 2016). The present study uses the solar occultation observations in equatorial regions of Titan that have been acquired by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft to infer similar information in a broader wavelength range. Preliminary studies have proven the interest of those solar occultation data in the seven atmospheric windows to constrain the aerosol number density, but could not directly compare with the Descent Imager and Spectral Radiometer (DISR) data because models predict that the density profile vary with latitude. The present study compares the DISR measurements of aerosol extinction coefficients and the solar occultation data acquired by the VIMS instrument onboard Cassini. These sets of data differ in their acquisition method and time, spectral range, and altitude: the DISR measurements have been taken in 2005, along a vertical line of sight, in the visible spectral range (490-950nm) and under 140km of altitude. The relevant solar occultation data at equator have been acquired in 2009, along a horizontal line of sight, in the IR range (0.9-5.1µm), with sun light scanning all altitudes for a long enough wavelength, namely in the five-micron atmospheric window. These sets of data have been analyzed previously, separately and using different models. Here, we present a cross analysis of these sets of data, that allows us to test the different models describing the density profile of aerosols. In addition to providing wavelength dependence of the extinction coefficient, the comparison allows us to assess the impact of refraction in Titan's atmosphere. It also provides optical depth and scattering properties that are crucial information

  19. Reflection formulae for ray tracing in uniaxial anisotropic media using Huygens's principle.

    Science.gov (United States)

    Alemán-Castañeda, Luis A; Rosete-Aguilar, Martha

    2016-11-01

    Ray tracing in uniaxial anisotropic materials is important because they are widely used for instrumentation, liquid-crystal displays, laser cavities, and quantum experiments. There are previous works regarding ray tracing refraction and reflection formulae using the common electromagnetic theory approach, but only the refraction formulae have been deduced using Huygens's principle. In this paper we obtain the reflection expressions using this unconventional approach with a specific coordinate system in which both refraction and reflection formulae are simplified as well as their deduction. We compute some numerical examples to compare them with the common expressions obtained using electromagnetic theory.

  20. Huygens' principle and radiation tails in a weak Schwarzschild fields

    Energy Technology Data Exchange (ETDEWEB)

    Piir, I. (Tartuskij Gosudarstvennyj Univ. (USSR))

    1983-01-01

    In approximation of a weak gravitational field the formula generalized Poisson formula for the wave equation is derived and the mechanism of tail aprearance of radial waves is discussed. It is shown that if the initial data of the Cauchy problem differ from zero in the two-connnected region of the initial hypersurface embracing by its internal boundary the Schwarzchild singularity there always arises the radiation tail through a linear approximation of the Huygens principle realized everywhere in a flat space-time.

  1. Gravitational waves in Friedman-Lemaitre-Robertson-Walker cosmology, material perturbations and the Huygens principle

    CERN Document Server

    Kulczycki, Wojciech

    2016-01-01

    We analyze propagation equations for the polar modes of gravitational waves in cosmological space-times. We prove that polar gravitational waves must perturb --- unlike axial modes --- the material content of the Friedman-Lemaitre-Robertson-Walker spacetimes. The whole gravitational dynamics reduces to the single "master equation" that has the same form as for axial modes. That allows us to conclude that the status of the Huygens principle is the same for axial and gravitational waves. In particular, this principle is valid exactly in radiation spacetimes with the vanishing cosmological constant, and it is broken otherwise.

  2. The Cassini-Huygens visit to Saturn an historic mission to the ringed planet

    CERN Document Server

    Meltzer, Michael

    2015-01-01

    Cassini-Huygens was the most ambitious and successful space journey ever launched to the outer Solar System. This book examines all aspects of the journey: its conception and planning; the lengthy political processes needed to make it a reality; the engineering and development required to build the spacecraft; its 2.2-billion mile journey from Earth to the Ringed Planet; and the amazing discoveries from the mission. The author traces how the visions of a few brilliant scientists matured, gained popularity, and eventually became a reality. Innovative technical leaps were necessary to assemble such a multifaceted spacecraft and reliably operate it while it orbited a planet so far from our own. The Cassini-Huygens spacecraft design evolved from other deep space efforts, most notably the Galileo mission to Jupiter, enabling the voluminous, paradigm-shifting scientific data collected by the spacecraft.  Some of these discoveries are absolute gems. A small satellite that scientists once thought of as a dead pi...

  3. A model for the vertical sound speed and absorption profiles in Titan's atmosphere based on Cassini-Huygens data.

    Science.gov (United States)

    Petculescu, Andi; Achi, Peter

    2012-05-01

    Measurements of thermodynamic quantities in Titan's atmosphere during the descent of Huygens in 2005 are used to predict the vertical profiles for the speed and intrinsic attenuation (or absorption) of sound. The calculations are done using one author's previous model modified to accommodate non-ideal equations of state. The vertical temperature profile places the tropopause about 40 km above the surface. In the model, a binary nitrogen-methane composition is assumed for Titan's atmosphere, quantified by the methane fraction measured by the gas chromatograph/mass spectrometer (GCMS) onboard Huygens. To more accurately constrain the acoustic wave number, the variation of thermophysical properties (specific heats, viscosity, and thermal conductivity) with altitude is included via data extracted from the NIST Chemistry WebBook [URL webbook.nist.gov, National Institute of Standards and Technology Chemistry WebBook (Last accessed 10/20/2011)]. The predicted speed of sound profile fits well inside the spread of the data recorded by Huygens' active acoustic sensor. In the N(2)-dominated atmosphere, the sound waves have negligible relaxational dispersion and mostly classical (thermo-viscous) absorption. The cold and dense environment of Titan can sustain acoustic waves over large distances with relatively small transmission losses, as evidenced by the small absorption. A ray-tracing program is used to assess the bounds imposed by the zonal wind-measured by the Doppler Wind Experiment on Huygens-on long-range propagation.

  4. Sizes of the Smallest Particles at the Outer B Ring Edge, Huygens Ringlet, and Strange Ringlet

    Science.gov (United States)

    Eckert, Stephanie; Colwell, Josh E.; Becker, Tracy M.; Esposito, Larry W.

    2016-10-01

    The Cassini Ultraviolet Imaging Spectrograph (UVIS)'s High Speed Photometer (HSP) has observed stellar occultations of Saturn's rings that reveal ring structure at high resolution. We observe diffraction spikes at the sharp edges of some rings and ringlets where the observed signal exceeds the unocculted star signal, indicating that small particles are diffracting light into the detector. Becker et al. (2015 Icarus doi:10.1016/j.icarus.2015.11.001) analyzed data at the A ring edge and edges of the Encke gap. The smallest particle sizes were a few mm. We use the same technique to analyze the diffraction signal at the outer edge of the B ring and the edges of the so-called Strange ringlet near the outer edge of the Huygens Gap. While we see diffraction from sub-cm particles in the Strange Ringlet, detections from the wider Huygens Ringlet which resides in between the Strange Ringlet and the outer edge of the B ring are weaker and narrower, indicating a cutoff of the size distribution above 1 cm. At the outer edge of the B ring we find strong diffraction signals in 7 of 19 occultations for which the signal and geometry make the detection possible. The typical value of the smallest particle size (amin) is 4 mm and the derived slope of the power-law size distribution (q) is 2.9. The average amin is similar to the 4.5 mm average observed at the A ring outer edge while the q value is lower than the A ring outer edge value of 3.2. In the Strange Ringlet we find strong diffraction signals in 2 of 19 possible occultations for the outer edge and 1 of 17 possible occultations for the inner edge. The smallest particle size is ~5 mm and the derived slope of the power-law size distribution is 3.3. These values are similar to the average values at the A ring outer edge. The absence of a broad diffraction signal at the Huygens Ringlet suggests a different size distribution for that ring than for the Strange Ringlet and the outer several km of the B ring or perhaps less vigorous

  5. DLMS Voice Data Entry.

    Science.gov (United States)

    1980-06-01

    between operator and computer displayed on ADM-3A 20c A-I Possible Hardware Configuration for a Multistation Cartographic VDES ...this program a Voice Recognition System (VRS) which can be used to explore the use of voice data entry ( VDE ) in the DIMS or other cartographic data...Multi-Station Cartographic Voice Data Entry System An engineering development model voice data entry system ( VDES ) could be most efficiently

  6. Cavity-excited Huygens' metasurface antennas: near-unity aperture efficiency from arbitrarily-large apertures

    CERN Document Server

    Epstein, Ariel; Eleftheriades, George V

    2015-01-01

    One of the long-standing problems in antenna engineering is the realization of highly-directive beams using low-profile devices. In this paper we provide a solution to this problem by means of Huygens' metasurfaces (HMSs), based on the equivalence principle. This principle states that a given excitation can be transformed to a desirable aperture field by inducing suitable electric and magnetic surface currents. Building on this concept, we propose and demonstrate cavity-excited HMS antennas, where the single-source cavity excitation is designed to optimize aperture illumination, while the HMS facilitates the current distribution that ensures phase purity of aperture fields. The HMS breaks the coupling between the excitation and radiation spectrum typical to standard partially-reflecting surfaces, allowing tailoring of the aperture properties to produce a desirable radiation pattern. As shown, a single semianalytical formalism can be followed to achieve control of a variety of radiation features, such as the d...

  7. Passive Lossless Huygens Metasurfaces for Conversion of Arbitrary Source Field to Directive Radiation

    CERN Document Server

    Epstein, Ariel

    2014-01-01

    We present a semi-analytical formulation of the interaction between a given source field and a scalar Huygens metasurface (HMS), a recently introduced promising concept for wavefront manipulation based on a sheet of orthogonal electric and magnetic dipoles. Utilizing the equivalent surface impedance representation of these metasurfaces, we establish that an arbitrary source field can be converted into directive radiation via a passive lossless HMS if two physical conditions are met: local power conservation and local impedance equalization. Expressing the fields via their plane-wave spectrum and harnessing the slowly-varying envelope approximation we obtain semi-analytical formulae for the scattered fields, and prescribe the surface reactance required for the metasurface implementation. The resultant design procedure indicates that the local impedance equalization induces a Fresnel-like reflection, while local power conservation forms a radiating virtual aperture which follows the total excitation field magni...

  8. Dielectric Huygens' Metasurface for High-Efficiency Hologram Operating in Transmission Mode.

    Science.gov (United States)

    Zhao, Wenyu; Jiang, Huan; Liu, Bingyi; Song, Jie; Jiang, Yongyuan; Tang, Chengchun; Li, Junjie

    2016-01-01

    Conventional metasurface holograms relying on metal antennas for phase manipulation suffer from strong Ohmic loss and incomplete polarization conversion. The efficiency is limited to rather small values when operating in transmission mode. Here, we implement a high-efficiency transmissive metasurface hologram by leveraging the recently developed Huygens' metasurface to construct an electric and magnetic sheet with a transmission efficiency up to 86% and optical efficiency of 23.6%. The high-efficiency originates from the simultaneous excitations of the Mie-type electric and magnetic dipole resonances in the meta-atoms composed of silicon nanodisks. Our hologram shows high fidelity over a wide spectral range and promises to be an outstanding alternative for display applications.

  9. Entry at Venus

    Science.gov (United States)

    Venkatapathy, Ethiraj; Smith, Brandon

    2016-01-01

    This is lecture to be given at the IPPW 2016, as part of the 2 day course on Short Course on Destination Venus: Science, Technology and Mission Architectures. The attached presentation material is intended to be introduction to entry aspects of Venus in-situ robotic missions. The presentation introduces the audience to the aerodynamic and aerothermodynamic aspects as well as the loads, both aero and thermal, generated during entry. The course touches upon the system design aspects such as TPS design and both high and low ballistic coefficient entry system concepts that allow the science payload to be protected from the extreme entry environment and yet meet the mission objectives.

  10. Structure and physical conditions in the Huygens region of the Orion nebula

    Science.gov (United States)

    O'Dell, C. R.; Ferland, G. J.; Peimbert, M.

    2017-02-01

    Hubble Space Telescope images, MUSE maps of emission lines, and an atlas of high velocity resolution emission-line spectra have been used to establish for the first time correlations of the electron temperature, electron density, radial velocity, turbulence, and orientation within the main ionization front of the nebula. From the study of the combined properties of multiple features, it is established that variations in the radial velocity are primarily caused by the photoevaporating ionization front being viewed at different angles. There is a progressive increase of the electron temperature and density with decreasing distance from the dominant ionizing star θ1 Ori C. The product of these characteristics (ne × Te) is the most relevant parameter in modelling a blister-type nebula like the Huygens region, where this quantity should vary with the surface brightness in Hα. Several lines of evidence indicate that small-scale structure and turbulence exist down to the level of our resolution of a few arcseconds. Although photoevaporative flow must contribute at some level to the well-known non-thermal broadening of the emission lines, comparison of quantitative predictions with the observed optical line widths indicates that it is not the major additive broadening component. Derivation of Te values for H+ from radio+optical and optical-only ionized hydrogen emission showed that this temperature is close to that derived from [N II] and that the transition from the well-known flat extinction curve which applies in the Huygens region to a more normal steep extinction curve occurs immediately outside of the Bright Bar feature of the nebula.

  11. Incorporation of a spatial source distribution and a spatial sensor sensitivity in a laser ultrasound propagation model using a streamlined Huygens' principle.

    Science.gov (United States)

    Laloš, Jernej; Babnik, Aleš; Možina, Janez; Požar, Tomaž

    2016-03-01

    The near-field, surface-displacement waveforms in plates are modeled using interwoven concepts of Green's function formalism and streamlined Huygens' principle. Green's functions resemble the building blocks of the sought displacement waveform, superimposed and weighted according to the simplified distribution. The approach incorporates an arbitrary circular spatial source distribution and an arbitrary circular spatial sensitivity in the area probed by the sensor. The displacement histories for uniform, Gaussian and annular normal-force source distributions and the uniform spatial sensor sensitivity are calculated, and the corresponding weight distributions are compared. To demonstrate the applicability of the developed scheme, measurements of laser ultrasound induced solely by the radiation pressure are compared with the calculated waveforms. The ultrasound is induced by laser pulse reflection from the mirror-surface of a glass plate. The measurements show excellent agreement not only with respect to various wave-arrivals but also in the shape of each arrival. Their shape depends on the beam profile of the excitation laser pulse and its corresponding spatial normal-force distribution.

  12. Double entry bookkeeping vs single entry bookkeeping

    Directory of Open Access Journals (Sweden)

    Ileana Andreica

    2016-11-01

    Full Text Available Abstract: A financial management eficiently begin, primarily, with an accounting record kept in the best possible conditions, this being conditioned on the adoption of a uniform forms, rational, clear and simple accounting. Throughout history, there have been known two forms of accounting: the simple and double entry. Romanian society after 1990 underwent a substantial change in social structure, the sector on which put a great emphasis being private, that of small manufacturers, peddler, freelance, who work independently and authorized or as associative form (family enterprises, various associations (owners, tenants, etc., liberal professions, etc.. They are obliged to keep a simple bookkeeping, because they have no juridical personality. Companies with legal personality are required to keep double entry bookkeeping; therefore, knowledge and border demarcation between the two forms of organisation of accounting is an essential. The material used for this work is mainly represented by the financial and accounting documents, by the analysis of the economic, by legislative updated sources, and as the method was used the comparison method, using hypothetical data, in case of an authorized individual and a legal entity. Based on the chosen material, an authorized individual (who perform single entry accounting system and a juridical entity (who perform double entry accounting system were selected comparative case studies, using hypothetical data, were analysed advantages and disadvantages in term of fiscal, if using two accounting systems, then were highlighted some conclusion that result.

  13. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2013-01-01

    Mobile probing is a method, developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time and space......). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings point...... to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face). The development...

  14. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2012-01-01

    Mobile probing is a method, which has been developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time...... and space). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings...... point to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face...

  15. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2012-01-01

    Mobile probing is a method, which has been developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time...... and space). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings...... point to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face...

  16. What can High Resolution Inertial Rotation Sensing do for the Geosciences? (Christiaan Huygens Medal Lecture)

    Science.gov (United States)

    Schreiber, Karl Ulrich

    2016-04-01

    Strap-Down inertial gyroscopes are essential for the attitude control of aircrafts - they keep helicopters and planes in the sky. What if the same technology is strapped to the Earth? It will allow the observation and understanding of the geophysical processes behind minute changes of the rate of rotation as well as variations of the orientation of the instantaneous axis of rotation of the Earth. Unlike the highly dynamic aircraft motion geophysical signals are very small and act on much longer timescales. Therefore we have to make a suitable gyro for the application in the Geosciences significantly more sensitive and stable than aircraft gyros, improving them by many orders of magnitude. Large scale optical interferometers suggest themselves for this purpose, but the requirements are demanding. We have built and explored a variety of monolithic and heterolithic ring lasers, spanning areas between 1 and more than 800 m2. On this road of applying a locally installed high resolution active optical interferometer to a global measurement quantity (earth rotation), we have encountered a number of serious challenges some of which already puzzled Christiaan Huygens some 300 years ago.

  17. Structure and Physical Conditions in the Huygens Region of the Orion Nebula

    CERN Document Server

    O'Dell, C R; Peimbert, M

    2016-01-01

    HST images, MUSE maps of emission-lines, and an atlas of high velocity resolution emission-line spectra have been used to establish for the firrst time correlations of the electron temperature, electron density, radial velocity, turbulence, and orientation within the main ionization front of the nebula. From the study of the combined properties of multiple features, it is established that variations in the radial velocity are primarily caused by the photo-evaporating ionization front being viewed at different angles. There is a progressive increase of the electron temperature and density with decreasing distance from the dominant ionizing star Theta1 Ori C. The product of these characteristics (NexTe) is the most relevant parameter in modeling a blister-type nebula like the Huygens Region, where this quantity should vary with the surface brightness in Halpha. Several lines of evidence indicate that small-scale structure and turbulence exists down to the level of our resolution of a few arcseconds. Although ph...

  18. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2013-01-01

    to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face). The development...

  19. Shuttle entry guidance

    Science.gov (United States)

    Harpold, J. C.; Graves, C. A., Jr.

    1978-01-01

    This paper describes the design of the entry guidance for the Space Shuttle Orbiter. This guidance provides the steering commands for trajectory control from initial penetration of the earth's atmosphere until the terminal area guidance is activated at an earth-relative speed of 2500 fps. At this point, the Orbiter is at a distance of about 50 nmi from the runway threshold, and at an altitude of about 80,000 ft. The entry guidance design is based on an analytic solution of the equations of motion defining the drag acceleration profile that meets the terminal criteria of the entry flight while maintaining the flight within systems and operational constraints. Guidance commands, which are based on a control law that ensures damping of oscillatory type trajectory motion, are computed to steer the Orbiter to this drag acceleration profile.

  20. 对特殊监管区域出入境检验检疫监管规定的分析与探讨%Analysis and probing of special supervision district entry-exit inspection and quarantme supervision regulation

    Institute of Scientific and Technical Information of China (English)

    李文青; 刘宏波; 阎青

    2012-01-01

    Due to the General Administration of Quality Supervision for special areas’ supervision is according to the old and single fact,which is not match with its development status.And current Entry and Exit Inspection and Quarantine are found,which can’t satisfy the inspection of special supervision areas’ need.In this situation,the Quality Administration issued the"On the Supervision and Management of Special Inspection and Quarantine Area(drafts)",to seek the advice from the internals of Inspection and Quarantine.By careful analysis the Inspection and Quarantine agencies’ historic evolution and advantages and disadvantages of custom clearance management,the author puts forward some ideas and opinions;hopes these ideas can help the inspection work keep pace with The Times,and more in line with the actual business needs.%由于出入境检验检疫机构对海关特殊监管区域进行监管的依据陈旧单一,与特殊监管区域的发展现状并不匹配,并且已经越来越不能满足特殊监管区域监管工作的实际需要。在上述情况下,质检总局下发了《关于对〈特殊监管区域检验检疫监督管理办法〉(征求意见稿)征求意见的函》,向检验检疫系统内征求对该办法的修改意见和建议。笔者通过认真分析检验检疫机构对特殊监管区域监督管理方面的历史沿革和利弊,提出了自己的一些见解和观点,希望能够对该办法的修订有所帮助并使检验检疫机构对特殊监管区域的监管工作能做到与时俱进,更加符合实际的业务需求。

  1. Built But Not Used, Needed But Not Built: Ground System Guidance Based On Cassini-Huygens Experience

    Science.gov (United States)

    Larsen, Barbara S.

    2006-01-01

    These reflections share insight gleaned from Cassini-Huygens experience in supporting uplink operations tasks with software. Of particular interest are developed applications that were not widely adopted and tasks for which the appropriate application was not planned. After several years of operations, tasks are better understood providing a clearer picture of the mapping of requirements to applications. The impact on system design of the changing user profile due to distributed operations and greater participation of scientists in operations is also explored. Suggestions are made for improving the architecture, requirements, and design of future systems for uplink operations.

  2. In Vitro Assessment of Optical Properties of Blood by Applying the Extended Huygens-Fresnel Principle to Time-Domain Optical Coherence Tomography Signal at 1300 nm

    Directory of Open Access Journals (Sweden)

    Dan P. Popescu

    2008-01-01

    Full Text Available A direct method for the measurement of the optical attenuation coefficient and the scattering anisotropy parameter based on applying the extended Huygens-Fresnel principle to optical coherence tomography images of blood is demonstrated. The images are acquired with a low-power probing beam at the wavelength of 1300 nm. Values of 12.15 mm−1 and 0.95 are found for the total attenuation coefficient and the scattering anisotropy factor, respectively. Also, as a preliminary step, the optical refraction index is determined with a precision of two decimal numbers directly from optical coherence images. The total attenuation coefficient and the scattering anisotropy factor are determined with precisions within experimental error margins of 5% and 2%, respectively. Readable OCT signal is obtained for a maximum propagation of light into blood of 0.25 mm. At the maximum probed depth, the measured signal is almost 103 smaller than its initial intensity when entering the sample.

  3. Deployable Entry-system Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Deployable Entry-system ProjecT (ADEPT) will develop requirements for the ADEPT flight test.  Prior entry systems used high mass thermal protection...

  4. Implications of internal processes in the interpretation of Titan's volatile inventory measured by Cassini-Huygens

    Science.gov (United States)

    Tobie, Gabriel; Gautier, D.; Hersant, F.; Lunine, J. I.

    2010-04-01

    Based on a series of data collected by Cassini-Huygens, we constrain the composition of the primordial bricks that formed Titan and quantify the chemical exchanges that occurred on Titan between the interior and the atmosphere since its accretion. Assuming that the bricks that formed Titan had a composition close to that of Enceladus and that of the planetesimals in the feeding zone of Saturn, we show that accretional melting generate an CH4-CO2-H2S - dominated atmosphere of more than 10 bars in equilibrium with a water ocean. The partial atmospheric pressure of ammonia remains low (ammonia into nitrogen is possible just after accretion but requires the water ocean remains in contact with the atmosphere during at least 10-50 millions of years. We show that most of the gas species, except N2 and 36Ar, released during accretion are likely to be re-incorporated in the interior during the post-accretional cooling phase, owing to efficient clathration at the water/ocean interface. During this process, xenon is predicted to be almost entirely removed from the primitive atmosphere and to be stored in the form of clathrate hydrate in the interior. The composition of gases released during the rest of the evolution is determined by the stability of each gas species relative to the clathrate phase and is expected to be dominated by CH4 and CO2, and to contain small amounts of argon and CO. It can be anticipated from our analysis that flows and deposits of CO2-rich materials would be associated to cryovolcanic events. Although the detection of 40Ar clearly support that interaction with the silicate phase has occurred during Titan's history, it is still unclear if significant chemical exchanges has occurred with the rocky core. Only detection of 38Ar and of the other noble gas isotopes by a future mission will permit to determine how the silicate phase has contributed to the volatile budget of Titan. Isotopic ratios in the surface materials (H2O, CO2 ice, organic matters, gas

  5. Re-entry and simulation

    Science.gov (United States)

    Jian, H.; Guangming, X.

    1983-11-01

    The physics of re-entry are discussed with emphasis on the re-entry trajectory of a ballistic missile. Factors discussed include re-entry speed, ablation, aerodynamic heating, and the plasma sheath shield. Experimental techniques used to simulate the aerodynamics and performance of missile systems include the computer, the wind tunnel, and free flight. Each of these is briefly discussed.

  6. Entry Vehicle Control System Design for the Mars Smart Lander

    Science.gov (United States)

    Calhoun, Philip C.; Queen, Eric M.

    2002-01-01

    The NASA Langley Research Center, in cooperation with the Jet Propulsion Laboratory, participated in a preliminary design study of the Entry, Descent and Landing phase for the Mars Smart Lander Project. This concept utilizes advances in Guidance, Navigation and Control technology to significantly reduce uncertainty in the vehicle landed location on the Mars surface. A candidate entry vehicle controller based on the Reaction Control System controller for the Apollo Lunar Excursion Module digital autopilot is proposed for use in the entry vehicle attitude control. A slight modification to the phase plane controller is used to reduce jet-firing chattering while maintaining good control response for the Martian entry probe application. The controller performance is demonstrated in a six-degree-of-freedom simulation with representative aerodynamics.

  7. Music in Spain in the 1670s through the eyes of Sébastien Chièze and Constantijn Huygens

    Directory of Open Access Journals (Sweden)

    Rasch, Rudolf A.

    2007-12-01

    Full Text Available In this contribution the various remarks about music in Spain that can be found in the correspondence between Sébastien Chièze (envoy on behalf of the Prince of Orange in Madrid and Constantijn Huygens (The Hague from 1672 to 1679 are discussed. Huygens asked Chièze to find for him a copy of Salinas’s De musica (1577, as well as Spanish airs and pieces for guitar. It took Chièze two years to find a copy of De musica in Spain and have it sent safely to Holland. Huygens did not like the Spanish airs sent by Chièze, by composers such as Juan del Vado, José Marín, Cristóbal Galán, and Juan Hidalgo. He found them too “African”. Nor did he like the guitar tablature, which turned the notation as he was used to seeing it upside down. Chièze also had a guitar made for Huygens in Madrid, but this instrument also met with disapproval. In the end, Chièze asked two Bolognese acquaintances, Giulio and Guido Bovio, to search for a suitable lute for Huygens in Bologna. They found two, but it is unknown whether these ever arrived in Holland. The contribution shows the importance of foreign (diplomatic contacts in the acquisition of musical articles, such as books about music, musical compositions and musical instruments.

    Este artículo trata de las diversas observaciones a propósito de la música en España, que se encuentran en la correspondencia entre Sébastien Chièze (embajador del Príncipe de Orange en Madrid y Constantijn Huygens (La Haya, entre 1672 y 1679. Huygens pidió a Chièze que le encontrara un ejemplar del De musica de Salinas (1577, así como tonadas españolas y piezas para guitarra. A Chièze le llevó dos años hallar una copia del De musica en territorio español y hacer que el libro llegara a Holanda sano y salvo. Las tonadas remitidas por Chièze (de compositores tales como Juan del Vado, José Marín, Cristóbal Galán y Juan Hidalgo, no gustaron nada a Huygens, que las halló demasiado “africanas”. Como

  8. Dynamics of Water Entry

    CERN Document Server

    Truscott, Tadd T; Techet, Alexandra H

    2008-01-01

    The hydrodynamics associated with water-entry of spheres can be highly variable with respect to the material and kinematic properties of the sphere. This series of five fluid dynamics videos illustrates several subtle but interesting variations that can be seen. The first series of videos contrasts the nature of impact ($Fr = U_o/\\sqrt{gd} = 5.15$) between a hydrophilic (wetting angle of $\\alpha$ = 60$^\\circ$) and hydrophobic sphere ($\\alpha$ = 120$^\\circ$), and illustrates how surface coating can affect whether or not an air cavity is formed; the views from the side and from above are synchronized in time. The second video series illustrates how spin and surface treatments can alter the splash and cavity formation following water entry. The spinning sphere ($S = \\omega r / U_o = 1.7$; $Fr = 5.15$) causes a wedge of fluid to be drawn into the cavity due to the no-slip condition and follows a curved trajectory. The non-spinning sphere ($Fr = 5.15$) has two distinct surface treatments on the left and right hemi...

  9. Quantitative evaluation of scattering in optical coherence tomography skin images using the extended Huygens-Fresnel theorem.

    Science.gov (United States)

    Avanaki, Mohammad R N; Podoleanu, Adrian Gh; Schofield, John B; Jones, Carole; Sira, Manu; Liu, Yan; Hojjat, Ali

    2013-03-10

    An optical properties extraction algorithm is developed based on enhanced Huygens-Fresnel light propagation theorem, to extract the scattering coefficient of a specific region in an optical coherence tomography (OCT) image. The aim is to quantitatively analyze the OCT images. The algorithm is evaluated using a set of phantoms with different concentrations of scatterers, designed based on Mie theory. The algorithm is then used to analyze basal cell carcinoma and healthy eyelid tissues, demonstrating distinguishable differences in the scattering coefficient between these tissues. In this study, we have taken advantage of the simplification introduced by the utilization of a dynamic focus OCT system. This eliminates the need to deconvolve the reflectivity profile with the confocal gate profile, as the sensitivity of the OCT system is constant throughout the axial range.

  10. 19 CFR 142.17 - One entry summary for multiple entries.

    Science.gov (United States)

    2010-04-01

    ...; DEPARTMENT OF THE TREASURY (CONTINUED) ENTRY PROCESS Entry Summary Documentation § 142.17 One entry summary... for which entries or immediate transportation entries have been filed. However, this provision is not.... (ii) Immediate transportation entries. Immediate transportation entries may be consolidated if the...

  11. Membrane fusion during poxvirus entry.

    Science.gov (United States)

    Moss, Bernard

    2016-12-01

    Poxviruses comprise a large family of enveloped DNA viruses that infect vertebrates and invertebrates. Poxviruses, unlike most DNA viruses, replicate in the cytoplasm and encode enzymes and other proteins that enable entry, gene expression, genome replication, virion assembly and resistance to host defenses. Entry of vaccinia virus, the prototype member of the family, can occur at the plasma membrane or following endocytosis. Whereas many viruses encode one or two proteins for attachment and membrane fusion, vaccinia virus encodes four proteins for attachment and eleven more for membrane fusion and core entry. The entry-fusion proteins are conserved in all poxviruses and form a complex, known as the Entry Fusion Complex (EFC), which is embedded in the membrane of the mature virion. An additional membrane that encloses the mature virion and is discarded prior to entry is present on an extracellular form of the virus. The EFC is held together by multiple interactions that depend on nine of the eleven proteins. The entry process can be divided into attachment, hemifusion and core entry. All eleven EFC proteins are required for core entry and at least eight for hemifusion. To mediate fusion the virus particle is activated by low pH, which removes one or more fusion repressors that interact with EFC components. Additional EFC-interacting fusion repressors insert into cell membranes and prevent secondary infection. The absence of detailed structural information, except for two attachment proteins and one EFC protein, is delaying efforts to determine the fusion mechanism.

  12. Shuttle entry guidance revisited

    Science.gov (United States)

    Mease, Kenneth D.; Kremer, Jean-Paul

    1992-08-01

    The Shuttle entry guidance concept is reviewed which is aimed at tracking a reference drag trajectory that leads to the specified range and velocity for the initiation of the terminal energy management phase. An approximate method of constructing the domain of attraction is proposed, and its validity is ascertained by simulation. An alternative guidance law yielding global exponential tracking in the absence of control saturation is derived using a feedback linearization method. It is noted that the alternative guidance law does not improve on the stability and performance of the current guidance law, for the operating domain and control capability of the Shuttle. It is suggested that the new guidance law with a larger operating domain and increased lift-to-drag capability would be superior.

  13. Shuttle entry guidance revisited

    Science.gov (United States)

    Mease, Kenneth D.; Kremer, Jean-Paul

    1992-01-01

    The Shuttle entry guidance concept is reviewed which is aimed at tracking a reference drag trajectory that leads to the specified range and velocity for the initiation of the terminal energy management phase. An approximate method of constructing the domain of attraction is proposed, and its validity is ascertained by simulation. An alternative guidance law yielding global exponential tracking in the absence of control saturation is derived using a feedback linearization method. It is noted that the alternative guidance law does not improve on the stability and performance of the current guidance law, for the operating domain and control capability of the Shuttle. It is suggested that the new guidance law with a larger operating domain and increased lift-to-drag capability would be superior.

  14. Water Entry of Projectiles

    Science.gov (United States)

    Truscott, Tadd T.; Epps, Brenden P.; Belden, Jesse

    2014-01-01

    The free-surface impact of solid objects has been investigated for well over a century. This canonical problem is influenced by many physical parameters, including projectile geometry, material properties, fluid properties, and impact parameters. Through advances in high-speed imaging and visualization techniques, discoveries about the underlying physics have improved our understanding of these phenomena. Improvements to analytical and numerical models have led to critical insights into cavity formation, the depth and time of pinch-off, forces, and trajectories for myriad different impact parameters. This topic spans a wide range of regimes, from low-speed entry phenomena dominated by surface tension to high-speed ballistics, for which cavitation is important. This review surveys experimental, theoretical, and numerical studies over this broad range, utilizing canonical images where possible to enhance intuition and insight into the rich phenomena.

  15. Probe Storage

    NARCIS (Netherlands)

    Gemelli, Marcellino; Abelmann, Leon; Engelen, Johan B.C.; Khatib, Mohammed G.; Koelmans, Wabe W.; Zaboronski, Olog; Campardo, Giovanni; Tiziani, Federico; Laculo, Massimo

    2011-01-01

    This chapter gives an overview of probe-based data storage research over the last three decades, encompassing all aspects of a probe recording system. Following the division found in all mechanically addressed storage systems, the different subsystems (media, read/write heads, positioning, data chan

  16. Cultural probes

    DEFF Research Database (Denmark)

    Madsen, Jacob Østergaard

    2016-01-01

    The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation.......The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation....

  17. Tactile Data Entry System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Building on our successful Phase I Tactile Data Entry program, Barron Associates proposes development of a Glove-Enabled Computer Operations (GECO) system to permit...

  18. Entry, Descent, Landing Animation (Animation)

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Entry, Descent, Landing animation This animation illustrates the path the Stardust return capsule will follow once it enters Earth's atmosphere.

  19. Entry, Descent, Landing Animation (Animation)

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Entry, Descent, Landing animation This animation illustrates the path the Stardust return capsule will follow once it enters Earth's atmosphere.

  20. Orion Entry Handling Qualities Assessments

    Science.gov (United States)

    Bihari, B.; Tiggers, M.; Strahan, A.; Gonzalez, R.; Sullivan, K.; Stephens, J. P.; Hart, J.; Law, H., III; Bilimoria, K.; Bailey, R.

    2011-01-01

    The Orion Command Module (CM) is a capsule designed to bring crew back from the International Space Station (ISS), the moon and beyond. The atmospheric entry portion of the flight is deigned to be flown in autopilot mode for nominal situations. However, there exists the possibility for the crew to take over manual control in off-nominal situations. In these instances, the spacecraft must meet specific handling qualities criteria. To address these criteria two separate assessments of the Orion CM s entry Handling Qualities (HQ) were conducted at NASA s Johnson Space Center (JSC) using the Cooper-Harper scale (Cooper & Harper, 1969). These assessments were conducted in the summers of 2008 and 2010 using the Advanced NASA Technology Architecture for Exploration Studies (ANTARES) six degree of freedom, high fidelity Guidance, Navigation, and Control (GN&C) simulation. This paper will address the specifics of the handling qualities criteria, the vehicle configuration, the scenarios flown, the simulation background and setup, crew interfaces and displays, piloting techniques, ratings and crew comments, pre- and post-fight briefings, lessons learned and changes made to improve the overall system performance. The data collection tools, methods, data reduction and output reports will also be discussed. The objective of the 2008 entry HQ assessment was to evaluate the handling qualities of the CM during a lunar skip return. A lunar skip entry case was selected because it was considered the most demanding of all bank control scenarios. Even though skip entry is not planned to be flown manually, it was hypothesized that if a pilot could fly the harder skip entry case, then they could also fly a simpler loads managed or ballistic (constant bank rate command) entry scenario. In addition, with the evaluation set-up of multiple tasks within the entry case, handling qualities ratings collected in the evaluation could be used to assess other scenarios such as the constant bank angle

  1. Currency union entries and trade

    OpenAIRE

    Nitsch, Volker

    2005-01-01

    Recent research suggests that adopting a common currency increases bilateral trade. In this paper, I explore experiences of currency union entry in the post-war period and find no effect on trade. Previous results derived from a large panel data set (covering more than 200 countries from 1948 through 1997) appear to depend crucially on the assumption of symmetry between currency union exits and entries: While countries leaving a currency union experience significant declines in trade, currenc...

  2. Mobile probes

    DEFF Research Database (Denmark)

    2016-01-01

    A project investigating the effectiveness of a collection of online resources for teachers' professional development used mobile probes as a data collection method. Teachers received questions and tasks on their mobile in a dialogic manner while in their everyday context as opposed to in an inter......A project investigating the effectiveness of a collection of online resources for teachers' professional development used mobile probes as a data collection method. Teachers received questions and tasks on their mobile in a dialogic manner while in their everyday context as opposed...... to in an interview. This method provided valuable insight into the contextual use, i.e. how did the online resource transfer to the work practice. However, the research team also found that mobile probes may provide the scaffolding necessary for individual and peer learning at a very local (intra-school) community...... level. This paper is an initial investigation of how the mobile probes process proved to engage teachers in their efforts to improve teaching. It also highlights some of the barriers emerging when applying mobile probes as a scaffold for learning....

  3. Possible Niches For Extant Life On Titan In Light Of The First Six Years Of Cassini/Huygens Results

    Science.gov (United States)

    Grinspoon, David H.; Schulze-Makuch, D.

    2010-10-01

    At the 2005 DPS meeting we presented an assessment of the possibility of extant life on Titan after the first year of the Cassini mission at Saturn. We suggested then that hydrogenation of photochemically produced acetylene could provide metabolic energy for near-surface organisms and also replenish atmospheric methane (Schulze-Makuch and Grinspoon, 2005). In this talk we will offer a brief reassessment of the possibility of extant life in light of five more years of the Cassini/Huygens results, including the recent reports suggesting a lack of acetylene on the surface (Clark et al., 2010) and a possible sink of H2 at the surface (Strobel, 2010). Both results are consistent with earlier predictions for the existence of an acetylene-powered biosphere on Titan (Schulze-Makuch and Grinspoon, 2005; McKay and Smith, 2005), but can potentially be explained by more prosaic phenomena. D. Schulze-Makuch and D. H. Grinspoon(2005), Biologically Enhanced Energy and Carbon Cycling on Titan? Astrobiology 5, 560-567; Clarke, R.N. et al. (2020), Detection and Mapping of Hydrocarbon Deposits on Titan, JGR-Planets; Strobel, D.F(2010) Molecular hydrogen in Titan's atmosphere: Implications of the measured tropospheric and thermospheric mole fractions. Icarus; McKay, C.P., Smith, H.D.( 2005) Possibilities for methanogenic life in liquid methane on the surface of Titan. Icarus 178, 274-276.

  4. Cavity-excited Huygens' metasurface antennas for near-unity aperture illumination efficiency from arbitrarily large apertures.

    Science.gov (United States)

    Epstein, Ariel; Wong, Joseph P S; Eleftheriades, George V

    2016-01-21

    One of the long-standing problems in antenna engineering is the realization of highly directive beams using low-profile devices. In this paper, we provide a solution to this problem by means of Huygens' metasurfaces (HMSs), based on the equivalence principle. This principle states that a given excitation can be transformed to a desirable aperture field by inducing suitable electric and (equivalent) magnetic surface currents. Building on this concept, we propose and demonstrate cavity-excited HMS antennas, where the single-source-fed cavity is designed to optimize aperture illumination, while the HMS facilitates the current distribution that ensures phase purity of aperture fields. The HMS breaks the coupling between the excitation and radiation spectra typical to standard partially reflecting surfaces, allowing tailoring of the aperture properties to produce a desirable radiation pattern, without incurring edge-taper losses. The proposed low-profile design yields near-unity aperture illumination efficiencies from arbitrarily large apertures, offering new capabilities for microwave, terahertz and optical radiators.

  5. Huygens and Barrow, Newton and Hooke. Pioneers in mathematical analysis and catastrophe theory from evolvents to quasicrystals.

    Science.gov (United States)

    Arnol'D, V. I.

    This book is an English translation of the Russian original of 1989. It is based on a college lecture commemorating the tercentenary of Newton's book Philosophiae Naturalis Principia Mathematica. The author retraces the beginnings of mathematical analysis and theoretical physics in the works of the great scientists of the 17th century, and recounts the history of the discovery of the law of gravitation, discussions Newton had with Hooke and Leibniz, and much more. Some of Huygens' and Newton's ideas, several centuries ahead of their time, were developed only recently. The author follows the link between their inception and the break-throughs in contemporary mathematics and physics. The book provides present-day generalizations of Newton's theorems on the elliptical shape of orbits, attraction of spheres, and on the transcendence of Abelian integrals; it offers a brief review of the theory of regular and chaotic movement in celestial mechanics, including, for example, the problem of ports in the distribution of smaller planets and a discussion of the structure of planetary rings.

  6. Conductivity Probe

    Science.gov (United States)

    2008-01-01

    The Thermal and Electrical Conductivity Probe (TECP) for NASA's Phoenix Mars Lander took measurements in Martian soil and in the air. The needles on the end of the instrument were inserted into the Martian soil, allowing TECP to measure the propagation of both thermal and electrical energy. TECP also measured the humidity in the surrounding air. The needles on the probe are 15 millimeters (0.6 inch) long. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  7. 19 CFR 191.143 - Drawback entry.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) DRAWBACK Foreign-Built Jet Aircraft Engines Processed in the United States § 191.143 Drawback entry. (a) Filing of entry. Drawback entries covering these foreign-built jet aircraft engines shall be filed on Customs Form 7551, modified to show that the entry covers jet aircraft engines processed...

  8. 19 CFR 142.16 - Entry summary documentation.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Entry summary documentation. 142.16 Section 142.16... TREASURY (CONTINUED) ENTRY PROCESS Entry Summary Documentation § 142.16 Entry summary documentation. (a) Entry summary not filed at time of entry. When the entry documentation is filed before the entry...

  9. Pollution Probe.

    Science.gov (United States)

    Chant, Donald A.

    This book is written as a statement of concern about pollution by members of Pollution Probe, a citizens' anti-pollution group in Canada. Its purpose is to create public awareness and pressure for the eventual solution to pollution problems. The need for effective government policies to control the population explosion, conserve natural resources,…

  10. Autonomous gliding entry guidance with

    Directory of Open Access Journals (Sweden)

    Guo Jie

    2015-10-01

    Full Text Available This paper presents a novel three-dimensional autonomous entry guidance for relatively high lift-to-drag ratio vehicles satisfying geographic constraints and other path constraints. The guidance is composed of onboard trajectory planning and robust trajectory tracking. For trajectory planning, a longitudinal sub-planner is introduced to generate a feasible drag-versus-energy profile by using the interpolation between upper boundary and lower boundary of entry corridor to get the desired trajectory length. The associated magnitude of the bank angle can be specified by drag profile, while the sign of bank angle is determined by lateral sub-planner. Two-reverse mode is utilized to satisfy waypoint constraints and dynamic heading error corridor is utilized to satisfy no-fly zone constraints. The longitudinal and lateral sub-planners are iteratively employed until all of the path constraints are satisfied. For trajectory tracking, a novel tracking law based on the active disturbance rejection control is introduced. Finally, adaptability tests and Monte Carlo simulations of the entry guidance approach are performed. Results show that the proposed entry guidance approach can adapt to different entry missions and is able to make the vehicle reach the prescribed target point precisely in spite of geographic constraints.

  11. Reconstruction of the Genesis Entry

    Science.gov (United States)

    Desai, Prasun N.; Qualls, Garry D.; Schoenenberger, Mark

    2007-01-01

    An overview of the reconstruction analyses performed for the Genesis capsule entry is described. The results indicate that the actual entry prior to the drogue deployment failure was very close to the pre-entry predictions. The capsule landed 8.3 km south of the desired target at Utah Test and Training Range. Analysis on infrared video footage (obtained from the tracking stations) during the descent estimated the onset of the capsule tumble at Mach 0.9. Frequency analysis on the infrared video data indicates that the aerodynamics generated for the Genesis capsule reasonably predicted the drag and static stability. Observations of the heatshield support the pre-entry simulation estimates of a small hypersonic angles-of-attack, since there is very little, if any, charring of the shoulder region or the aftbody. Through this investigation, an overall assertion can be made that all the data gathered from the Genesis entry is consistent with flight performance that was close to the nominal preentry prediction. Consequently, the design principles and methodologies utilized for the flight dynamics, aerodynamics, and aerothermodynamics analyses have been corroborated.

  12. Membongkar Akuntansi Double Entry Systems

    Directory of Open Access Journals (Sweden)

    Whedy Prasetyo

    2013-08-01

    Full Text Available Double entry isa process of recording transactions that always involve at least two accounts ofwhich changes (increases or decreases have consequences to maintain a balance equation. This is a simple basic accounting, that the use of the funds must alwaysbe equal to the acquisition of funds. The equation is not able to include some business events that are responses to the development of business environment. A proposed view is based on the interaction of researcher (New Bond with accountant (Mrs M to dismantle the double entry accounting through Maurice Merleau Ponty's approach (1906-1961. The results prove that physical aspects of knowledge willcontinue to evolve according to environmental interactions.

  13. Re-entry flight clearance

    NARCIS (Netherlands)

    Juliana, S.

    2006-01-01

    The objective of the research was to identify and evaluate promising mathematical techniques for re-entry flight clearance. To fulfil this objective, two mathematical methods were investigated and developed: μ analysis for linear models and interval analysis for both linear and non-linear model

  14. Components of Visual Prior Entry

    Science.gov (United States)

    Schneider, Keith A.; Bavelier, Daphne

    2003-01-01

    The prior entry hypothesis contends that attention accelerates sensory processing, shortening the time to perception. Typical observations supporting the hypothesis may be explained equally well by response biases, changes in decision criteria, or sensory facilitation. In a series of experiments conducted to discriminate among the potential…

  15. Entry Facilitation by Environmental Groups

    NARCIS (Netherlands)

    van der Made, Allard; Schoonbeek, Lambert

    We consider a model of vertical product differentiation where consumers care about the environmental damage their consumption causes. An environmental group is capable of increasing consumers' environmental concern via a costly campaign. We show that the prospect of such a campaign can induce entry

  16. Entry Facilitation by Environmental Groups

    NARCIS (Netherlands)

    van der Made, Allard; Schoonbeek, Lambert

    2009-01-01

    We consider a model of vertical product differentiation where consumers care about the environmental damage their consumption causes. An environmental group is capable of increasing consumers' environmental concern via a costly campaign. We show that the prospect of such a campaign can induce entry

  17. Cubesat Application for Planetary Entry (CAPE) Missions: Micro-Return Capsule (MIRCA)

    Science.gov (United States)

    Esper, Jaime

    2016-01-01

    The Cubesat Application for Planetary Entry Missions (CAPE) concept describes a high-performing Cubesat system which includes a propulsion module and miniaturized technologies capable of surviving atmospheric entry heating, while reliably transmitting scientific and engineering data. The Micro Return Capsule (MIRCA) is CAPE's first planetary entry probe flight prototype. Within this context, this paper briefly describes CAPE's configuration and typical operational scenario, and summarizes ongoing work on the design and basic aerodynamic characteristics of the prototype MIRCA vehicle. CAPE not only opens the door to new planetary mission capabilities, it also offers relatively low-cost opportunities especially suitable to university participation. In broad terms, CAPE consists of two main functional components: the "service module" (SM), and "CAPE's entry probe" (CEP). The SM contains the subsystems necessary to support vehicle targeting (propulsion, ACS, computer, power) and the communications capability to relay data from the CEP probe to an orbiting "mother-ship". The CEP itself carries the scientific instrumentation capable of measuring atmospheric properties (such as density, temperature, composition), and embedded engineering sensors for Entry, Descent, and Landing (EDL). The first flight of MIRCA was successfully completed on 10 October 2015 as a "piggy-back" payload onboard a NASA stratospheric balloon launched from Ft. Sumner, NM.

  18. 19 CFR 142.3a - Entry numbers.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Entry numbers. 142.3a Section 142.3a Customs... (CONTINUED) ENTRY PROCESS Entry Documentation § 142.3a Entry numbers. (a) Placement on CBP forms. The importer or broker shall place an 11 character entry number on the entry and corresponding entry...

  19. Bi-weekly waterfowl survey data entry

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Data sheet for the entry of bi-weekly waterfowl survey data from the state of Kansas. This Excel file contains the data entry sheet and a chart displaying waterfowl...

  20. HERA: an atmospheric probe to unveil the depths of Saturn

    Science.gov (United States)

    Mousis, Olivier; Atkinson, David H.; Amato, Michael; Aslam, Shahid; Atreya, Sushil K.; Blanc, Michel; Bolton, Scott J.; Brugger, Bastien; Calcutt, Simon; Cavalié, Thibault; Charnoz, Sébastien; Coustenis, Athena; DELEUIL, Magali; Ferri, Francesca; Fletcher, Leigh N.; Guillot, Tristan; Hartogh, Paul; Holland, Andrew; Hueso, Ricardo; Keller, Christoph; Kessler, Ernst; Lebreton, Jean-Pierre; leese, Mark; Lellouch, Emmanuel; Levacher, Patrick; Marty, Bernard; Morse, Andrew; Nixon, Conor; Reh, Kim R.; Renard, Jean-Baptiste; Sanchez-Lavega, Agustin; Schmider, François-Xavier; Sheridan, Simon; Simon, Amy A.; Snik, Frans; Spilker, Thomas R.; Stam, Daphne M.; Venkatapathy, Ethiraj; Vernazza, Pierre; Waite, J. Hunter; Wurz, Peter

    2016-10-01

    The Hera Saturn entry probe mission is proposed as an M-class mission led by ESA with a significant collaboration with NASA. It consists of a Saturn atmospheric probe and a Carrier-Relay spacecraft. Hera will perform in situ measurements of the chemical and isotopic compositions as well as the dynamics of Saturn's atmosphere, with the goal of improving our understanding of the origin, formation, and evolution of Saturn, the giant planets and their satellite systems, with extrapolation to extrasolar planets.The primary science objectives will be addressed by an atmospheric entry probe that would descend under parachute and carry out in situ measurements beginning in the stratosphere to help characterize the location and properties of the tropopause, and continue into the troposphere to pressures of at least 10 bars. All of the science objectives, except for the abundance of oxygen, which may be only addressed indirectly via observations of species whose abundances are tied to the abundance of water, can be achieved by reaching 10 bars. As in previous highly successful collaborative efforts between ESA and NASA, the proposed mission has a baseline concept based on a NASA-provided carrier/data relay spacecraft that would deliver the ESA-provided atmospheric probe to the desired atmospheric entry point at Saturn. ESA's proposed contribution should fit well into the M5 Cosmic Vision ESA call cost envelope.A nominal mission configuration would consist of a probe that detaches from the carrier one to several months prior to probe entry. Subsequent to probe release, the carrier trajectory would be deflected to optimize the over-flight phasing of the probe descent location for both probe data relay as well as performing carrier approach and flyby science, and would allow multiple retransmissions of the probe data for redundancy. The Saturn atmospheric entry probe would in many respects resemble the Jupiter Galileo probe. It is anticipated that the probe architecture for

  1. Flavivirus Entry Receptors: An Update

    Directory of Open Access Journals (Sweden)

    Manuel Perera-Lecoin

    2013-12-01

    Full Text Available Flaviviruses enter host cells by endocytosis initiated when the virus particles interact with cell surface receptors. The current model suggests that flaviviruses use at least two different sets of molecules for infectious entry: attachment factors that concentrate and/or recruit viruses on the cell surface and primary receptor(s that bind to virions and direct them to the endocytic pathway. Here, we present the currently available knowledge regarding the flavivirus receptors described so far with specific attention to C-type lectin receptors and the phosphatidylserine receptors, T-cell immunoglobulin and mucin domain (TIM and TYRO3, AXL and MER (TAM. Their role in flavivirus attachment and entry as well as their implication in the virus biology will be discussed in depth.

  2. 19 CFR 122.42 - Aircraft entry.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Aircraft entry. 122.42 Section 122.42 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY AIR COMMERCE REGULATIONS Aircraft Entry and Entry Documents; Electronic Manifest Requirements...

  3. Sunk costs, entry deterrence, and financial constraints

    NARCIS (Netherlands)

    Arping, S.; Diaw, K.M.

    2008-01-01

    This paper studies how sunk costs affect a financially constrained incumbent's ability to deter entry into its market. Sunk costs make it less attractive to the incumbent to accommodate entry by liquidating assets in place and exiting the market. This may render entry by a prospective rival

  4. Sport entries and qualification manual: Nanjing 2014

    OpenAIRE

    2014-01-01

    Sport entries constitute an important part of the delegation registration process of the Nanjing 2014 Summer Youth Olympic Games. This manual aims to introduce to NOCs the process, relevant policies and requirements regarding sport entries so as to ensure that NOCs can successfully complete the entries for their athletes to the Nanjing 2014 Youth Olympic Games.

  5. Methodology and Politics in Science: The Fate of Huygens' 1673 Proposal of the Seconds Pendulum as an International Standard of Length and Some Educational Suggestions

    Science.gov (United States)

    Matthews, Michael R.

    This paper is part of a larger work on the history, philosophy and utilisation of pendulum motion studies (Matthews 2000). The paper deals with the fate of Christiaan Huygens 1673 proposal to use the length of a seconds pendulum (effectively one metre) as a universal, natural and objective standard of length. This is something which, if it had been adopted, would have been of inestimable scientific, commercial and cultural benefit. Why it was not originally adopted in the late seventeenth century, and why it was again rejected in the late eighteenth century (1795) when the Revolutionary Assembly in France adopted the metric system with the metre being defined as one ten-millionth of the quarter meridan distance - raise interesting questions about the methodology and politics of science. Given that pendulum motion is a standard component of all science courses throughout the world, and given that most science education reforms, including the US National Science Education Standards and recent Australian state reforms, require that something of the big picture of science be conveyed to students (the relationship of science to culture, commerce, history and philosophy) - it is suggested that these educational goals can be advanced by teaching about the fate of Huygens' proposal.

  6. Conceptual shape optimization of entry vehicles applied to capsules and winged fuselage vehicles

    CERN Document Server

    Dirkx, Dominic

    2017-01-01

    This book covers the parameterization of entry capsules, including Apollo capsules and planetary probes, and winged entry vehicles such as the Space Shuttle and lifting bodies. The aerodynamic modelling is based on a variety of panel methods that take shadowing into account, and it has been validated with flight and wind tunnel data of Apollo and the Space Shuttle. The shape optimization is combined with constrained trajectory analysis, and the multi-objective approach provides the engineer with a Pareto front of optimal shapes. The method detailed in Conceptual Shape Optimization of Entry Vehicles is straightforward, and the output gives the engineer insight in the effect of shape variations on trajectory performance. All applied models and algorithms used are explained in detail, allowing for reconstructing the design tool to the researcher’s requirements. Conceptual Shape Optimization of Entry Vehicles will be of interest to both researchers and graduate students in the field of aerospace engineering, an...

  7. 19 CFR 143.36 - Form of immediate delivery, entry and entry summary.

    Science.gov (United States)

    2010-04-01

    ... Form of immediate delivery, entry and entry summary. (a) Electronic form of data. If Customs determines... 19 Customs Duties 2 2010-04-01 2010-04-01 false Form of immediate delivery, entry and entry summary. 143.36 Section 143.36 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF...

  8. ExoMars Entry, Descent, and Landing Science

    Science.gov (United States)

    Karatekin, Özgür; Forget, Francois; Withers, Paul; Colombatti, Giacomo; Aboudan, Alessio; Lewis, Stephen; Ferri, Francesca; Van Hove, Bart; Gerbal, Nicolas

    2016-07-01

    Schiaparelli, the Entry Demonstrator Module (EDM) of the ESA ExoMars Program will to land on Mars on 19th October 2016. The ExoMars Atmospheric Mars Entry and Landing Investigations and Analysis (AMELIA) team seeks to exploit the Entry Descent and Landing (EDL) engineering measurements of Schiaparelli for scientific investigations of Mars' atmosphere and surface. ExoMars offers a rare opportunity to perform an in situ investigation of the martian environment over a wide altitude range. There has been only 7 successfully landing on the surface of Mars, from the Viking probes in the 1970's to the Mars Science Laboratory (MSL) in 2012. ExoMars EDM is equipped with an instrumented heat shield like MSL. These novel flight sensors complement conventional accelerometer and gyroscope instrumentation, and provide additional information to reconstruct atmospheric conditions with. This abstract outlines general atmospheric reconstruction methodology using complementary set of sensors and in particular the use of surface pressure and radio data. In addition, we discuss the lessons learned from previous EDL and the plans for ExoMars AMELIA data analysis.

  9. Matrix Completion from Noisy Entries

    CERN Document Server

    Keshavan, Raghunandan H; Oh, Sewoong

    2009-01-01

    Given a matrix M of low-rank, we consider the problem of reconstructing it from noisy observations of a small, random subset of its entries. The problem arises in a variety of applications, from collaborative filtering (the `Netflix problem') to structure-from-motion and positioning. We study a low complexity algorithm introduced by Keshavan et al.(2009), based on a combination of spectral techniques and manifold optimization, that we call here OptSpace. We prove performance guarantees that are order-optimal in a number of circumstances.

  10. Proximal Probes Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Proximal Probes Facility consists of laboratories for microscopy, spectroscopy, and probing of nanostructured materials and their functional properties. At the...

  11. Adaptive Text Entry for Mobile Devices

    DEFF Research Database (Denmark)

    Proschowsky, Morten Smidt

    for mobile devices and a framework for adaptive context-aware language models. Based on analysis of current text entry methods, the requirements to the new text entry methods are established. Transparent User guided Prediction (TUP) is a text entry method for devices with one dimensional touch input. It can......The reduced size of many mobile devices makes it difficult to enter text with them. The text entry methods are often slow or complicated to use. This affects the performance and user experience of all applications and services on the device. This work introduces new easy-to-use text entry methods...... to improve the models of human motor behaviour. TUP-Key is a variant of TUP, designed for 12 key phone keyboards. It is introduced in the thesis but has not been implemented or evaluated. Both text entry methods support adaptive context-aware language models. YourText is a framework for adaptive context...

  12. Preventing re-entry to foster care.

    Science.gov (United States)

    Carnochan, Sarah; Rizik-Baer, Daniel; Austin, Michael J

    2013-01-01

    Re-entry to foster care generally refers to circumstances in which children who have been discharged from foster care to be reunified with their family of origin, adopted, or provided kinship guardianship are returned to foster care. In the context of the federal performance measurement system, re-entry refers specifically to a return to foster care following an unsuccessful reunification. The federal Children and Family Services Review measures re-entry to foster care with a single indicator, called the permanency of reunification indicator, one of four indicators comprising the reunification composite measure. This review focuses on research related to the re-entry indicator, including the characteristics of children, caregivers and families, as well as case and child welfare services that are associated with a higher or lower risk of re-entry to foster care. Promising post-reunification services designed to prevent re-entry to foster care are described.

  13. Scientific Value of a Saturn Atmospheric Probe Mission

    Science.gov (United States)

    Simon-Miller, A. A.; Lunine, J. I.; Atreya, S. K.; Spilker, T. R.; Coustenis, A.; Atkinson, D. H.

    2012-01-01

    Atmospheric entry probe mISSions to the giant planets can uniquely discriminate between competing theories of solar system formation and the origin and evolution of the giant planets and their atmospheres. This provides for important comparative studies of the gas and ice giants, and to provide a laboratory for studying the atmospheric chemistries, dynamics, and interiors of all the planets including Earth. The giant planets also represent a valuable link to extrasolar planetary systems. As outlined in the recent Planetary Decadal Survey, a Saturn Probe mission - with a shallow probe - ranks as a high priority for a New Frontiers class mission [1].

  14. Border Crossing/Entry Data - Border Crossing/Entry Data Time Series tool

    Data.gov (United States)

    Department of Transportation — The dataset is known as “Border Crossing/Entry Data.” The Bureau of Transportation Statistics (BTS) Border Crossing/Entry Data provides summary statistics to the...

  15. Entry Into a Care Trajectory

    Directory of Open Access Journals (Sweden)

    Normand Carpentier

    2013-06-01

    Full Text Available A broad range of services are developing in response to the needs of an aging population. Although most interventions are carried out in the patient’s living environment—at the heart of society—few studies on service utilization refer to social theory. This paper suggests that studies on older people with chronic health conditions would benefit from a stronger theoretical foundation. Drawing on 15 in-depth interviews, it highlights the relevance of individualization processes and the network society, 2 central theoretical concerns in sociology. The research provides a unique perspective on the entry into the care trajectory and expands our comprehension of the emergence of a social organization that can respond to the needs of elderly patients. Data of this nature may be useful in service planning and the development of a care-centered approach.

  16. Probe tip heating assembly

    Science.gov (United States)

    Schmitz, Roger William; Oh, Yunje

    2016-10-25

    A heating assembly configured for use in mechanical testing at a scale of microns or less. The heating assembly includes a probe tip assembly configured for coupling with a transducer of the mechanical testing system. The probe tip assembly includes a probe tip heater system having a heating element, a probe tip coupled with the probe tip heater system, and a heater socket assembly. The heater socket assembly, in one example, includes a yoke and a heater interface that form a socket within the heater socket assembly. The probe tip heater system, coupled with the probe tip, is slidably received and clamped within the socket.

  17. Pico Reentry Probes: Affordable Options for Reentry Measurements and Testing

    Science.gov (United States)

    Ailor, William H.; Kapoor, Vinod B.; Allen, Gay A., Jr.; Venkatapathy, Ethiraj; Arnold, James O.; Rasky, Daniel J.

    2005-01-01

    It is generally very costly to perform in-space and atmospheric entry experiments. This paper presents a new platform - the Pico Reentry Probe (PREP) - that we believe will make targeted flight-tests and planetary atmospheric probe science missions considerably more affordable. Small, lightweight, self-contained, it is designed as a "launch and forget" system, suitable for experiments that require no ongoing communication with the ground. It contains a data recorder, battery, transmitter, and user-customized instrumentation. Data recorded during reentry or space operations is returned at end-of-mission via transmission to Iridium satellites (in the case of earth-based operations) or a similar orbiting communication system for planetary missions. This paper discusses possible applications of this concept for Earth and Martian atmospheric entry science. Two well-known heritage aerodynamic shapes are considered as candidates for PREP: the shape developed for the Planetary Atmospheric Experiment Test (PAET) and that for the Deep Space II Mars Probe.

  18. Foreign Entry and Heterogeneous Growth of Firms

    DEFF Research Database (Denmark)

    Deng, Paul Duo; Jefferson, Gary H.

    We adopt the framework of Schumpeterian creative destruction formalized by Aghion et al. (2009) to analyze the impact of foreign entry on the productivity growth of domestic firms. In the face of foreign entry, domestic firms exhibit heterogeneous patterns of growth depending on their technological...

  19. Predicting the Diversity of Foreign Entry Modes

    DEFF Research Database (Denmark)

    Hashai, Niron; Geisler Asmussen, Christian; Benito, Gabriel;

    2007-01-01

    diversity across value chain activities and host markets. Analyzing a sample of Israeli based firms we show that larger firms exhibit a higher degree of entry mode diversity both across value chain activities and across host markets. Higher levels of knowledge intensity are also associated with more...... diversity in firms' entry modes across both dimensions....

  20. Foreign Entry and Heterogeneous Growth of Firms

    DEFF Research Database (Denmark)

    Deng, Paul Duo; Jefferson, Gary H.

    We adopt the framework of Schumpeterian creative destruction formalized by Aghion et al. (2009) to analyze the impact of foreign entry on the productivity growth of domestic firms. In the face of foreign entry, domestic firms exhibit heterogeneous patterns of growth depending on their technologic...

  1. Thermal Soak Analysis of Earth Entry Vehicles

    Science.gov (United States)

    Agrawal, Parul; Sepka, Steven A.; Aliaga, Jose F.; Venkatapathy, Ethiraj; Samareh, Jamshid A.

    2012-01-01

    The Multi-Mission Earth Entry Vehicle project is developing an integrated tool called Multi Mission System Analysis for Planetary Entry Descent and Landing that will provide key technology solutions including mass sizing, aerodynamics, aerothermodynamics, and thermal and structural analysis for any given sample return mission. Thermal soak analysis and temperature predictions of various components including the payload container of the entry vehicle are part of the solution that this tool will offer to mission designers. The present paper focuses on the thermal soak analysis of an entry vehicle design based on the Mars Sample Return entry vehicle geometry and discusses a technical approach to develop parametric models for thermal soak analysis that will be integrated into the tool.

  2. 19 CFR 142.3 - Entry documentation required.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Entry documentation required. 142.3 Section 142.3... TREASURY (CONTINUED) ENTRY PROCESS Entry Documentation § 142.3 Entry documentation required. (a) Contents. Except as provided in paragraph (b) of this section, the entry documentation required to secure...

  3. Soil gas and radon entry into a simple test structure: Comparison of experimental and modelling results

    DEFF Research Database (Denmark)

    Andersen, C.E.; Søgaard-Hansen, J.; Majborn, B.

    1994-01-01

    A radon test structure has been established at a field site at Riso National Laboratory. Measurements have been made of soil gas entry rates, pressure couplings and radon depletion. The experimental results have been compared with results obtained from measured soil parameters and a two......-dimensional steady-state numerical model of Darcy flow and combined diffusive and advective transport of radon. For most probe locations, the calculated values of the pressure couplings and the radon depletion agree well with the measured values, thus verifying important elements of the Darcy flow approximation......, and the ability of the model to treat combined diffusive and advective transport of radon. However, the model gives an underestimation of the soil gas entry rate. Even if it is assumed that the soil has a permeability equal to the highest of the measured values, the model underestimates the soil gas entry rate...

  4. LABORATORY VOICE DATA ENTRY SYSTEM.

    Energy Technology Data Exchange (ETDEWEB)

    PRAISSMAN,J.L.SUTHERLAND,J.C.

    2003-04-01

    We have assembled a system using a personal computer workstation equipped with standard office software, an audio system, speech recognition software and an inexpensive radio-based wireless microphone that permits laboratory workers to enter or modify data while performing other work. Speech recognition permits users to enter data while their hands are holding equipment or they are otherwise unable to operate a keyboard. The wireless microphone allows unencumbered movement around the laboratory without a ''tether'' that might interfere with equipment or experimental procedures. To evaluate the potential of voice data entry in a laboratory environment, we developed a prototype relational database that records the disposal of radionuclides and/or hazardous chemicals Current regulations in our laboratory require that each such item being discarded must be inventoried and documents must be prepared that summarize the contents of each container used for disposal. Using voice commands, the user enters items into the database as each is discarded. Subsequently, the program prepares the required documentation.

  5. Mobile Game Probes

    DEFF Research Database (Denmark)

    Borup Lynggaard, Aviaja

    2006-01-01

    This paper will examine how probes can be useful for game designers in the preliminary phases of a design process. The work is based upon a case study concerning pervasive mobile phone games where Mobile Game Probes have emerged from the project. The new probes are aimed towards a specific target...... group and the goal is to specify the probes so they will cover the most relevant areas for our project. The Mobile Game Probes generated many interesting results and new issues occurred, since the probes came to be dynamic and favorable for the process in new ways....

  6. Novel Approaches to Inhibit HIV Entry

    Directory of Open Access Journals (Sweden)

    Chukwuka A. Didigu

    2012-02-01

    Full Text Available Human Immunodeficiency Virus (HIV entry into target cells is a multi-step process involving binding of the viral glycoprotein, Env, to its receptor CD4 and a coreceptor—either CCR5 or CXCR4. Understanding the means by which HIV enters cells has led to the identification of genetic polymorphisms, such as the 32 base-pair deletion in the ccr5 gene (ccr5∆32 that confers resistance to infection in homozygous individuals, and has also resulted in the development of entry inhibitors—small molecule antagonists that block infection at the entry step. The recent demonstration of long-term control of HIV infection in a leukemic patient following a hematopoietic stem cell transplant using cells from a ccr5∆32 homozygous donor highlights the important role of the HIV entry in maintaining an established infection and has led to a number of attempts to treat HIV infection by genetically modifying the ccr5 gene. In this review, we describe the HIV entry process and provide an overview of the different classes of approved HIV entry inhibitors while highlighting novel genetic strategies aimed at blocking HIV infection at the level of entry.

  7. Advances in spacecraft atmospheric entry guidance

    Science.gov (United States)

    Benito Manrique, Joel

    In order to advance entry guidance technology two different research areas have been explored with the objective of increasing the reachable landing area and the landing accuracy for future Mars missions. Currently only the northern hemisphere of Mars is available for landing due to its low elevation. Only low elevation landing sites have the necessary atmospheric density to allow landing using current Entry, Descent and Landing (EDL) technology. In order to reach most of the Ancient Highlands, the majority of the southern hemisphere, advanced EDL technology is needed in multiple fields, including entry guidance. The first research area is the definition and applications of reachable and controllable sets for entry. The definition of the reachable and controllable sets provides a framework for the study of the capabilities of an entry vehicle in a given planet. Reachable and controllable sets can be used to comprehensively characterize the envelope of trajectories that a vehicle can fly, the sites it can reach and the entry states that can be accommodated. The sets can also be used for the evaluation of trajectory planning algorithms and to assist in the selection of the entry or landing sites. In essence, the reachable and controllable sets offer a powerful vehicle and trajectory analysis and design framework that allows for better mission design choices. In order to illustrate the use of the sets, they are computed for a representative Mars mission using two different vehicle configurations. The sets characterize the impact of the vehicle configuration on the entry capability. Furthermore, the sets are used to find the best skip-entry trajectory for a return from the Moon mission, highlighting the utility of the sets in atmospheric maneuvers other than entry. The second research area is the development of the components of an entry guidance algorithm that allow high elevation landing and provide as well high landing accuracy. The approach taken follows the

  8. Entry Regulation under Asymmetric Information about Demand

    Directory of Open Access Journals (Sweden)

    Paula Sarmento

    2010-01-01

    Full Text Available We investigate how an incumbent firm can use the regulatory policy about entry and the informational advantage to protect his market position. This question is studied through the construction of a signalling game where we assume that the regulator has less information about demand than the firms. We conclude that there is a pooling equilibrium and partially separating equilibria in which entry is deterred and, if demand is high, there will be insufficient entry. The final effect on welfare depends on the tradeoff between short-run benefits (lower price and long-run losses (weaker competition.

  9. Market entry strategies into the BRIC countries

    DEFF Research Database (Denmark)

    Boyd, Britta; Dyhr Ulrich, Anna Marie

    2014-01-01

    Based on a sample of 177 exporting SMEs, this study investigates what market entry strategy is used by Danish family and non-family businesses. From a resource-based view, three critical internal factors (risk, flexibility and control) affecting the entry mode choice into the BRIC markets...... when entering the BRIC markets. In contrast, family firms choose high commitment entry modes which involve high risk and low flexibility when entering the BRIC markets. Further implications discuss the suitability of export strategies to BRIC markets for managers of Danish family and non-family firms....

  10. Texting while driving: is speech-based text entry less risky than handheld text entry?

    Science.gov (United States)

    He, J; Chaparro, A; Nguyen, B; Burge, R J; Crandall, J; Chaparro, B; Ni, R; Cao, S

    2014-11-01

    Research indicates that using a cell phone to talk or text while maneuvering a vehicle impairs driving performance. However, few published studies directly compare the distracting effects of texting using a hands-free (i.e., speech-based interface) versus handheld cell phone, which is an important issue for legislation, automotive interface design and driving safety training. This study compared the effect of speech-based versus handheld text entries on simulated driving performance by asking participants to perform a car following task while controlling the duration of a secondary text-entry task. Results showed that both speech-based and handheld text entries impaired driving performance relative to the drive-only condition by causing more variation in speed and lane position. Handheld text entry also increased the brake response time and increased variation in headway distance. Text entry using a speech-based cell phone was less detrimental to driving performance than handheld text entry. Nevertheless, the speech-based text entry task still significantly impaired driving compared to the drive-only condition. These results suggest that speech-based text entry disrupts driving, but reduces the level of performance interference compared to text entry with a handheld device. In addition, the difference in the distraction effect caused by speech-based and handheld text entry is not simply due to the difference in task duration.

  11. Integrated Entry Guidance for Reusable Launch Vehicle

    Institute of Scientific and Technical Information of China (English)

    NING Guo-dong; ZHANG Shu-guang; FANG Zhen-ping

    2007-01-01

    A method for the implementation of integrated three-degree-of-freedom constrained entry guidance for reusable launch vehicle is presented. Given any feasible entry conditions, terminal area energy management interface conditions, and the reference trajectory generated onboard then, the method can generate a longitudinal guidance profile rapidly, featuring linear quadratic regular method and a proportional-integral-derivative tracking law with time-varying gains, which satisfies all the entry corridor constraints and meets the requirements with high precision. Afterwards, by utilizing special features of crossrange parameter, establishing bank-reversal corridor,and determining bank-reversals according to dynamically adjusted method, the algorithm enables the lateral entry guidance system to fly a wide range of missions and provides reliable and good performance in the presence of significant aerodynamic modeling uncertainty.Fast trajectory guidance profiles and simulations with a reusable launch vehicle model for various missions and aerodynamic uncertainties are presented to demonstrate the capacity and reliability of this method.

  12. Border Crossing/Entry Data - Boarder Crossing

    Data.gov (United States)

    Department of Transportation — Border Crossing/Entry Data provides summary statistics for incoming crossings at the U.S.-Canadian and the U.S.-Mexican border at the port level. Data are available...

  13. Entry Mode and Performance of Nordic Firms

    DEFF Research Database (Denmark)

    Wulff, Jesper

    2015-01-01

    This study investigates whether the relationship between mode of international market entry and non-location bound international experience is weaker for firms that are large or have a high foreign to total sales ratio, labeled multinational experience. Empirical evidence based on 250 foreign...... market entries made by Norwegian, Danish and Swedish firms suggests that the association between equity mode choice and non-location bound international experience diminishes in the presence of higher levels of multinational experience. Furthermore, firms whose entry mode choice is predicted by the model...... including the proposed moderating effect, on average, yield higher post-entry performance. This study sheds light on inconsistent results found in previous research investigating the impact of international experience and has practical implications for managerial decision-making....

  14. The Effects of Entry in Bilateral Oligopoly

    Directory of Open Access Journals (Sweden)

    Alex Dickson

    2013-06-01

    Full Text Available The purpose of this paper is to study the effects of entry into the market for a single commodity in which both sellers and buyers are permitted to interact strategically. With the inclusion of an additional seller, the market is quasi-competitive: the price falls and volume of trade increases, as expected. However, contrary to the conventional wisdom, existing sellers’ payoffs may increase. The conditions under which entry by new sellers raises the equilibrium payoffs of existing sellers are derived. These depend in an intuitive way on the elasticity of a strategic analog of demand and the market share of existing sellers, and encompass entirely standard economic environments. Similar results are derived relating to the entry of additional buyers and the effects of entry on both sides of the market are investigated.

  15. Properties of Ultrasound Probes

    OpenAIRE

    Rusina, M.

    2015-01-01

    This work deals with the measurement properties of ultrasound probes. Ultrasound probes and their parameters significantly affect the quality of the final image. In this work there are described the possibility of measuring the spatial resolution, sensitivity of the probe and measuring the length of the dead zone. Ultrasound phantom ATS Multi Purpose Phantom Type 539 was used for measurements.

  16. Entry and exit decisions under uncertainty

    DEFF Research Database (Denmark)

    Kongsted, Hans Christian

    1996-01-01

    This paper establishes the general deterministic limit that corresponds to Dixit's model of entry and exit decisions under uncertainty. The interlinked nature of decisions is shown to be essential also in the deterministic limit. A numerical example illustrates the result......This paper establishes the general deterministic limit that corresponds to Dixit's model of entry and exit decisions under uncertainty. The interlinked nature of decisions is shown to be essential also in the deterministic limit. A numerical example illustrates the result...

  17. Hypersonic and planetary entry flight mechanics

    Science.gov (United States)

    Vinh, N. X.; Busemann, A.; Culp, R. D.

    1980-01-01

    The book treats hypersonic flight trajectories and atmospheric entry flight mechanics in light of their importance for space shuttle entry. Following a review of the structures of planetary atmospheres and aerodynamic forces, equations are derived for flight over a spherical planet, and the performance of long-range hypervelocity vehicles in extra-atmospheric flight is analyzed. Consideration is then given to vehicle trajectories in the powered and atmospheric reentry phases of flight, and several first-order solutions are derived for various planetary entry situations. The second-order theory of Loh for entry trajectories is presented along with the classical theories of Yaroshevskii and Chapman for entry into planetary atmospheres, and the thermal problems encountered in hypersonic flight are analyzed. A unified theory for entry into planetary atmospheres is then introduced which allows the performance of a general type of lifting vehicle to be studied, and applied to the analysis of orbit contraction due to atmospheric drag, flight with lift modulation and lateral maneuvers.

  18. The Outer Planets and their Moons Comparative Studies of the Outer Planets prior to the Exploration of the Saturn System by Cassini-Huygens

    CERN Document Server

    Encrenaz, T; Owen, T. C; Sotin, C

    2005-01-01

    This volume gives an integrated summary of the science related to the four giant planets in our solar system. It is the result of an ISSI workshop on «A comparative study of the outer planets before the exploration of Saturn by Cassini-Huygens» which was held at ISSI in Bern on January 12-16, 2004. Representatives of several scientific communities, such as planetary scientists, astronomers, space physicists, chemists and astrobiologists have met with the aim to review the knowledge on four major themes: (1) the study of the formation and evolution processes of the outer planets and their satellites, beginning with the formation of compounds and planetesimals in the solar nebula, and the subsequent evolution of the interiors of the outer planets, (2) a comparative study of the atmospheres of the outer planets and Titan, (3) the study of the planetary magnetospheres and their interactions with the solar wind, and (4) the formation and properties of satellites and rings, including their interiors, surfaces, an...

  19. Approach to atmospheric laser-propagation theory based on the extended Huygens-Fresnel principle and a self-consistency concept.

    Science.gov (United States)

    Bochove, Erik J; Rao Gudimetla, V S

    2017-01-01

    We propose a self-consistency condition based on the extended Huygens-Fresnel principle, which we apply to the propagation kernel of the mutual coherence function of a partially coherent laser beam propagating through a turbulent atmosphere. The assumption of statistical independence of turbulence in neighboring propagation segments leads to an integral equation in the propagation kernel. This integral equation is satisfied by a Gaussian function, with dependence on the transverse coordinates that is identical to the previous Gaussian formulation by Yura [Appl. Opt.11, 1399 (1972)APOPAI0003-693510.1364/AO.11.001399], but differs in the transverse coherence length's dependence on propagation distance, so that this established version violates our self-consistency principle. Our formulation has one free parameter, which in the context of Kolmogorov's theory is independent of turbulence strength and propagation distance. We determined its value by numerical fitting to the rigorous beam propagation theory of Yura and Hanson [J. Opt. Soc. Am. A6, 564 (1989)JOAOD60740-323210.1364/JOSAA.6.000564], demonstrating in addition a significant improvement over other Gaussian models.

  20. 用惠更斯面等效原理证明零场定理%Using Huygens' surface equivalence principle to prove the extinction theorem

    Institute of Scientific and Technical Information of China (English)

    侯维娜; 杜惠平

    2006-01-01

    The field equivalence principle, one of the fundamental concepts in electromagnetics, has numerous applications. However, it is not easy for people to understand it thoroughly. Especially,it is even harder to understand the extinction theorem and its realization in practice. In this article the authors use Huygens' surface equivalence principle to prove the extinction theorem, which is the fundamental concepts in electromagnetics. And this method proved to be a simple and good one in practice.%场等效原理是电磁学的基本定理之一,但场等效原理特别是零场定理很难被人理解,人们很难想象在一个区域中的场等效为原问题的场,而在另一个区域中却为零场.用惠更斯面等效原理证明了零场定理,该方法简单明了,易于理解,是一个很好的证明方法.

  1. Amino acid precursors from a simulated lower atmosphere of Titan, Experiments of cosmic ray energy source with 13C- and 18O-stable isotope probing mass spectrometry

    CERN Document Server

    Taniuchi, Toshinori; Kobayashi, Kensei

    2013-01-01

    The organic haze of aerosols that shrouds the Saturnian moon Titan has previously been studied by both observations and laboratory simulation experiments. Here we report the abiotic formation of amino acid precursors in complex organic molecules during experimental simulation of the environment near Titan's surface with proton irradiation. Pyrolysis of the organic molecules formed in the simulated Titan atmosphere by proton irradiation at 600 degree-C yielded compounds that contained HCN and NH3. These experimental results are consistent with the molecular information obtained by pyrolysis gas chromatography-mass spectrometry (pyrolysis GC-MS) of samples collected by the Huygens probe to Titan. Scanning electron microscopy (SEM) and three-dimensional atomic force microscopy (AFM) images of the irradiation products reveal nanometer-scale filaments and globules in complex amorphous structures (approximately 1000 Da). Isotope probing experiments by matrix-assisted laser desorption ionization time-of-flight mass ...

  2. 19 CFR 142.44 - Entry number range.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Entry number range. 142.44 Section 142.44 Customs... (CONTINUED) ENTRY PROCESS Line Release § 142.44 Entry number range. After an application for Line Release has received final approval, filers must provide the port director, in writing, with a range of entry...

  3. 77 FR 5681 - Establishment of Global Entry Program

    Science.gov (United States)

    2012-02-06

    ... assist in developing a marketing strategy. The firm has created a new Global Entry logo and tag line... SENTRI II. Analysis of Comments A. Program Performance and Entry Process B. Marketing of Global Entry C.... Marketing of Global Entry Comment: CBP received two comments suggesting that CBP should expand marketing...

  4. The membrane fusion step of vaccinia virus entry is cooperatively mediated by multiple viral proteins and host cell components.

    Directory of Open Access Journals (Sweden)

    Jason P Laliberte

    2011-12-01

    Full Text Available For many viruses, one or two proteins allow cell attachment and entry, which occurs through the plasma membrane or following endocytosis at low pH. In contrast, vaccinia virus (VACV enters cells by both neutral and low pH routes; four proteins mediate cell attachment and twelve that are associated in a membrane complex and conserved in all poxviruses are dedicated to entry. The aim of the present study was to determine the roles of cellular and viral proteins in initial stages of entry, specifically fusion of the membranes of the mature virion and cell. For analysis of the role of cellular components, we used well characterized inhibitors and measured binding of a recombinant VACV virion containing Gaussia luciferase fused to a core protein; viral and cellular membrane lipid mixing with a self-quenching fluorescent probe in the virion membrane; and core entry with a recombinant VACV expressing firefly luciferase and electron microscopy. We determined that inhibitors of tyrosine protein kinases, dynamin GTPase and actin dynamics had little effect on binding of virions to cells but impaired membrane fusion, whereas partial cholesterol depletion and inhibitors of endosomal acidification and membrane blebbing had a severe effect at the later stage of core entry. To determine the role of viral proteins, virions lacking individual membrane components were purified from cells infected with members of a panel of ten conditional-lethal inducible mutants. Each of the entry protein-deficient virions had severely reduced infectivity and except for A28, L1 and L5 greatly impaired membrane fusion. In addition, a potent neutralizing L1 monoclonal antibody blocked entry at a post-membrane lipid-mixing step. Taken together, these results suggested a 2-step entry model and implicated an unprecedented number of viral proteins and cellular components involved in signaling and actin rearrangement for initiation of virus-cell membrane fusion during poxvirus entry.

  5. 76 FR 82315 - Agency Information Collection Activities: Entry/Immediate Delivery Application and Simplified Entry

    Science.gov (United States)

    2011-12-30

    ... SECURITY U.S. Customs and Border Protection Agency Information Collection Activities: Entry/Immediate... Budget (OMB) for review and approval in accordance with the Paperwork Reduction Act: Entry/Immediate... process is conducted in accordance with 5 CFR 1320.10. DATES: Written comments should be received on or...

  6. Autonomous gliding entry guidance with geographic constraints

    Institute of Scientific and Technical Information of China (English)

    Guo Jie; Wu Xuzhong; Tang Shengjing

    2015-01-01

    This paper presents a novel three-dimensional autonomous entry guidance for relatively high lift-to-drag ratio vehicles satisfying geographic constraints and other path constraints. The guidance is composed of onboard trajectory planning and robust trajectory tracking. For trajectory planning, a longitudinal sub-planner is introduced to generate a feasible drag-versus-energy profile by using the interpolation between upper boundary and lower boundary of entry corridor to get the desired trajectory length. The associated magnitude of the bank angle can be specified by drag profile, while the sign of bank angle is determined by lateral sub-planner. Two-reverse mode is utilized to satisfy waypoint constraints and dynamic heading error corridor is utilized to satisfy no-fly zone constraints. The longitudinal and lateral sub-planners are iteratively employed until all of the path constraints are satisfied. For trajectory tracking, a novel tracking law based on the active disturbance rejection control is introduced. Finally, adaptability tests and Monte Carlo simulations of the entry guidance approach are performed. Results show that the proposed entry guidance approach can adapt to different entry missions and is able to make the vehicle reach the prescribed target point precisely in spite of geographic constraints.

  7. Financial Performance of Entry Mode Decisions

    DEFF Research Database (Denmark)

    Boyd, Britta; Dyhr Ulrich, Anna Marie; Hollensen, Svend

    2012-01-01

    Based on a survey of 170 Danish SMEs the paper examines influences on entry mode choices and the financial outcome of these decisions. The main research objectives are divided into two steps: Step 1: To determine the factors influencing the choice of foreign entry modes by Danish companies. Step ...... and implications are provided for companies willing to invest more into foreign markets in order to achieve a higher degree of control and better financial results.......Based on a survey of 170 Danish SMEs the paper examines influences on entry mode choices and the financial outcome of these decisions. The main research objectives are divided into two steps: Step 1: To determine the factors influencing the choice of foreign entry modes by Danish companies. Step 2......: To determine the relationship between the choice of entry mode and export performance, measured in terms of financial outcome. Drawing from transaction cost theory the authors develop and test a model where different factors affect the level of control chosen by the parent company. This study contributes...

  8. Shuttle program. MCC Level C formulation requirements: Entry guidance and entry autopilot

    Science.gov (United States)

    Harpold, J. C.; Hill, O.

    1980-01-01

    A set of preliminary entry guidance and autopilot software formulations is presented for use in the Mission Control Center (MCC) entry processor. These software formulations meet all level B requirements. Revision 2 incorporates the modifications required to functionally simulate optimal TAEM targeting capability (OTT). Implementation of this logic in the MCC must be coordinated with flight software OTT implementation and MCC TAEM guidance OTT. The entry guidance logic is based on the Orbiter avionics entry guidance software. This MCC requirements document contains a definition of coordinate systems, a list of parameter definitions for the software formulations, a description of the entry guidance detailed formulation requirements, a description of the detailed autopilot formulation requirements, a description of the targeting routine, and a set of formulation flow charts.

  9. Subaxial cervical pedicle screw insertion with newly defined entry point and trajectory: accuracy evaluation in cadavers.

    Science.gov (United States)

    Zheng, Xiujun; Chaudhari, Rahul; Wu, Chunhui; Mehbod, Amir A; Transfeldt, Ensor E

    2010-01-01

    Successful placement of cervical pedicle screws requires accurate identification of both entry point and trajectory. However, literature has not provided consistent recommendations regarding the direction of pedicle screw insertion and entry point location. The objective of this study was to define a guideline regarding the optimal entry point and trajectory in placing subaxial cervical pedicle screws and to evaluate the screw accuracy in cadaver cervical spines. The guideline for entry point and trajectory for each vertebra was established based on the recently published morphometric data. Six fresh frozen cervical spines (C3-C7) were used. There were two men and four women. After posterior exposure, the entry point was determined and the cortical bone of the entry point was removed using a 2-mm burr. Pilot holes were created with a cervical probe based on the guideline using fluoroscopy. After tapping, 3.5-mm screws with appropriate length were inserted. After screw insertion, every vertebra was dissected and inspected for pedicle breach. The pedicle width, height, pedicle transverse angulation and actual screw insertion angle were measured. A total of 60 pedicle screws were inserted. No statistical difference in pedicle width and height was found between the left and right sides for each level. The overall accuracy of pedicle screws was 83.3%. The remaining 13.3% screws had noncritical breach, and 3.3% had critical breach. The critical breach was not caused by the guideline. There was no statistical difference between the pedicle transverse angulation and the actual screw trajectory created using the guideline. There was statistical difference in pedicle width between the breach and non-breach screws. In conclusion, high success rate of subaxial cervical pedicle screw placement can be achieved using the recently proposed operative guideline and oblique views of fluoroscopy. However, careful preoperative planning and good surgical skills are still required to

  10. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

    Devkanya Dutta

    2000-12-01

    Activation of receptors coupled to the phospholipase C/IP3 signalling pathway results in a rapid release of calcium from its intracellular stores, eventually leading to depletion of these stores. Calcium store depletion triggers an influx of extracellular calcium across the plasma membrane, a mechanism known as the store-operated calcium entry or capacitative calcium entry. Capacitative calcium current plays a key role in replenishing calcium stores and activating various physiological processes. Despite considerable efforts, very little is known about the molecular nature of the capacitative channel and the signalling pathway that activates it. This review summarizes our current knowledge about store operated calcium entry and suggests possible hypotheses for its mode of activation.

  11. Modes and orders of market entry

    DEFF Research Database (Denmark)

    Ulhøi, John Parm

    2012-01-01

    This paper focuses on the initial questions of how and when to enter a market from the perspective of a firm. By entry mode is meant a firm’s strategy (innovation or imitation) for entering the market in response to environmental changes. Entry order refers to the related issue of market timing...... strategies are more ambiguous. Based on a corporate technology and innovation strategy perspective, the paper reconceptualises and extends existing modes and orders of market entry, and in particular clarifies the ambiguity associated with imitative strategies. Four distinct imitator strategies...... are identified. The paper closes with a brief discussion of limitations, avenues for future research, and implications for managers and affected policymakers....

  12. Atom probe crystallography

    National Research Council Canada - National Science Library

    Gault, Baptiste; Moody, Michael P; Cairney, Julie M; Ringer, Simon P

    2012-01-01

    This review addresses new developments in the emerging area of "atom probe crystallography", a materials characterization tool with the unique capacity to reveal both composition and crystallographic...

  13. Automated Re-Entry System using FNPEG

    Science.gov (United States)

    Johnson, Wyatt R.; Lu, Ping; Stachowiak, Susan J.

    2017-01-01

    This paper discusses the implementation and simulated performance of the FNPEG (Fully Numerical Predictor-corrector Entry Guidance) algorithm into GNC FSW (Guidance, Navigation, and Control Flight Software) for use in an autonomous re-entry vehicle. A few modifications to FNPEG are discussed that result in computational savings -- a change to the state propagator, and a modification to cross-range lateral logic. Finally, some Monte Carlo results are presented using a representative vehicle in both a high-fidelity 6-DOF (degree-of-freedom) sim as well as in a 3-DOF sim for independent validation.

  14. Form, its meaning, and dictionary entries

    Directory of Open Access Journals (Sweden)

    Violetta Koseska-Toszewa

    2015-11-01

    It is worth stressing that distinguishing between the form and its meaning in comparing the material 6 languages belonging to three different groups of Slavic languages (as is the case in the MONDILEX Project will allow us to avoid numeorus substantiva mistakes and erroneous conclusions. Hence dictionary entries should be verified and made uniform in that respect before they are “digitalized”... Distinction between the form and its meaning in a dictionary entry is fully possible, as shown by works of Z. Saloni (2002 and A.Przepiórkowski (2008.

  15. "Generic Entry and the Pricing of Pharmaceuticals"

    OpenAIRE

    Frank, Richard G.; David S. Salkever

    1995-01-01

    During the 1980s the share of prescriptions sold by retail pharmacies that was accounted for by generic products roughly doubled. The price response to generic entry of brand-name products has been a source of controversy. In this paper we estimate models of price responses to generic entry in the market for brand-name and generic drugs. We study a sample of 32 drugs that lost patent protection during the early to mid-1980s. Our results provide strong evidence that brand-name prices increase ...

  16. Probe effects in gas turbine combustor emissions measurements. Final report 1 Mar--1 Oct 78

    Energy Technology Data Exchange (ETDEWEB)

    Clark, J.A.; Peters, J.E.; Mellor, A.M.

    1979-06-01

    Four geometrically distinct, stainless steel probes are used to study the concentrations of CO, HC,, NO, and NOX at several different radial and two different axial positions within a simplified gas turbine combustor. The probes are all water cooled but do not employ an aerodynamic quench. They are designed to assess the effect of tip shape, tip to body proximity, and probe entry point on measured pollutant concentrations. Though probe entry point and tip to body proximity are shown to imperceptibly affect the pollutant concentrations, probe tip geometry has a marked impact on the measured pollutant levels. Specifically, the aerodynamic, tapered-tip probe yields depressed CO and HC, and elevated NO concetrations compared to other three blunt-tipped probes. Regarding reproducibility, the pollutant concentratins measured with one of the blunt-tipped probes in this study are compared to pollutant levels measured with the same probe three years ago Tuttle, et al. 1975). CO and HC are shown to be the most reproducible species, while NO and NOX acceptably but less accurately agree with past studies.

  17. Position-optimization on retained entry and backfilling wall in gob-side entry retaining techniques

    Institute of Scientific and Technical Information of China (English)

    Xiaowei Feng; Nong Zhang

    2015-01-01

    This study investigates the stability problem of gob-side entry retaining (GER) and backfilling wall which located under the key block B. Based on the combined research of elastic–plastic mechanics, structure mechanics and modern theory of mining-induced pressure, the caving characteristic and roof structure over the GER were analyzed, and the vertical force and the torque on retained entry roof were also derived as the position for the retained entry varies. On the basis of the specific geology in Huainan mining area, the results indicate that a relatively more stable position for retained entry neighbors the hinge point of block A and B, and it also located at a scope ranging from this point to the one-third length of block B in horizontal direction. As to appropriate position for backfilling wall, this study recommends partial-road-in backfilling method for GER. Field trial conducted at panel face 12418 of Xieqiao Mine demonstrates that the recommended width for original entry is 3.6 m and the preferred width proportion between original retained entry and original entry is 75%or so whereas the avoidable one is 88%or so. These findings provide qualitative references to the mines which share similar geology as what Huainan mining area characterized.

  18. 19 CFR 4.8 - Preliminary entry.

    Science.gov (United States)

    2010-04-01

    ... electronic equivalent of a complete Customs Form 1302 (Cargo Declaration), in the manner provided in § 4.7(b... 19 Customs Duties 1 2010-04-01 2010-04-01 false Preliminary entry. 4.8 Section 4.8 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE...

  19. 19 CFR 145.25 - Entry correct.

    Science.gov (United States)

    2010-04-01

    ... director believes the duty originally assessed was correct, he shall send the addressee a notice in writing... 19 Customs Duties 2 2010-04-01 2010-04-01 false Entry correct. 145.25 Section 145.25 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE...

  20. Continuous Aerodynamic Modelling of Entry Shapes

    NARCIS (Netherlands)

    Dirkx, D.; Mooij, E.

    2011-01-01

    During the conceptual design phase of a re-entry vehicle, the vehicle shape can be varied and its impact on performance evaluated. To this end, the continuous modeling of the aerodynamic characteristics as a function of the shape is useful in exploring the full design space. Local inclination method

  1. Radon entry into a simple test structure

    DEFF Research Database (Denmark)

    Andersen, C.E.; Søgaard-Hansen, J.; Majborn, B.

    1992-01-01

    A simple test structure for studies of radon entry into houses has been constructed at a field site at Riso National Laboratory. It consists of a 40 1, stainless-steel cylinder placed in a 0.52 m deep quadratic excavation with a side length of 2.4 m. The excavation is lined with an airtight...

  2. Flavivirus cell entry and membrane fusion

    NARCIS (Netherlands)

    Smit, Jolanda M.; Moesker, Bastiaan; Rodenhuis-Zybert, Izabela; Wilschut, Jan

    2011-01-01

    Flaviviruses, such as dengue virus and West Nile virus, are enveloped viruses that infect cells through receptor-mediated endocytosis and fusion from within acidic endosomes. The cell entry process of flaviviruses is mediated by the viral E glycoprotein. This short review will address recent advance

  3. Processes with multiple entries and exits

    NARCIS (Netherlands)

    Bergstra, J.A.; Stefanescu, G.

    1995-01-01

    This paper is an attempt to integrate the algebra of communicating processes (ACP) and the algebra of flownomials (AF). Basically, this means to combine axiomatized parallel and looping operators. To this end we introduce a model of process graphs with multiple entries and exits. In this model the u

  4. HIV-1 Entry Inhbitors: An Overview

    Science.gov (United States)

    Kuritzkes, Daniel R.

    2009-01-01

    Purpose of review This review provides an overview of HIV-1 entry inhibitors, with a focus on chemokine receptor antagonists. Recent findings Entry of HIV-1 into target cells is an ordered multi-step process involving attachment, co-receptor binding and fusion. Inhibitors of each step have been identified and shown to have antiviral activity in clinical trials. Phase 1-2 trials of monoclonal antibodies and small-molecule attachment inhibitors have demonstrated activity in HIV-1-infected subjects, but none has progressed to later phase clinical trials. The post-attachment inhibitor ibalizumab has shown activity in phase 1 and 2 trials; further studies are anticipated. The CCR5 antagonists maraviroc (now been approved for clinical use) and vicriviroc (in phase 3 trials) have shown significant benefit in controlled trials in treatment-experienced subjects; additional CCR5 antagonists are in various stages of clinical development. Targeting CXCR4 has proven to be more challenging. Although proof of concept has been demonstrated in phase 1-2 trials of two compounds, neither proved suitable for chronic administration. Little progress has been reported in developing longer acting or orally bioavailable fusion inhibitors. Summary ACCR5 antagonist and a fusion inhibitor are approved for use as HIV-1 entry inhibitors. Development of drugs targeting other steps in HIV-1 entry is ongoing. PMID:19339945

  5. Duopoly Dynamics with a Barrier to Entry

    NARCIS (Netherlands)

    Abbring, J.H.; Campbell, Jeffrey R.

    2007-01-01

    This paper considers the effects of raising the cost of entry for a potential competitor on infinite-horizon Markov-perfect duopoly dynamics with ongoing demand uncertainty. All entrants serving the model industry incur sunk costs, and exit avoids future fixed costs. We focus on the unique equilibri

  6. Entry modes of European firms in Vietnam

    Directory of Open Access Journals (Sweden)

    Daniel Simonet

    2012-09-01

    Full Text Available Purpose: The purpose of the paper is to explore the entry modes of EU firms setting up operations in Vietnam. Design/methodology/approach: we use a case study approach on Haymarket, Cadbury, Creative Education, Fairchild, Aventis and Artemisinin and Farming International using interviews from managerial professionals in Vietnam. Findings: Despite the fact that Vietnam has been opening up for more than 20 years, licensing is the preferred entry mode because of the risks involved in venturing with local firms; that preference signals a low level commitment and a high perception of risk and state interference. In line with Vietnam transition to state - rather than private market - capitalism, a foreign company opting for a joint-venture will do so with a state-owned rather than privately-owned company. The choice of a subsidiary can be explained by the lack of trust in partners and institutions, not by improvement in the socio-political environment. Limitations: In determining the entry mode strategy, the paper focuses on the Uppsala school’s “psychic distance” (e.g. cultural distance, lack of trust rather than on firm-specific advantages (Rugman, 1980; 2006. Key-words: international entry mode; emerging markets; subsidiary; joint-venture; India; Vietnam

  7. Internet portals as portfolios of entry options

    NARCIS (Netherlands)

    Perotti, E.C.; Rossetto, S.

    2000-01-01

    We investigate the valuation of platform investment, such as a software operating system or an Internet portal WebPage. Platform investment is the creation of an innovative distribution and production infrastructure, which increases access to customers; as a result it reduces entry costs in related

  8. Internet portals as portfolios of entry options

    NARCIS (Netherlands)

    Perotti, E.C.; Rossetto, S.

    2000-01-01

    We investigate the valuation of platform investment, such as a software operating system or an Internet portal WebPage. Platform investment is the creation of an innovative distribution and production infrastructure, which increases access to customers; as a result it reduces entry costs in related

  9. Flavivirus cell entry and membrane fusion

    NARCIS (Netherlands)

    Smit, Jolanda M.; Moesker, Bastiaan; Rodenhuis-Zybert, Izabela; Wilschut, Jan

    2011-01-01

    Flaviviruses, such as dengue virus and West Nile virus, are enveloped viruses that infect cells through receptor-mediated endocytosis and fusion from within acidic endosomes. The cell entry process of flaviviruses is mediated by the viral E glycoprotein. This short review will address recent advance

  10. Foreign Entry and Heterogeneous Growth of Firms

    DEFF Research Database (Denmark)

    Deng, Paul Duo; Jefferson, Gary H.

    distance from foreign firms. Domestic firms with smaller technological distance from their foreign counterparts tend to experience faster productivity growth, while firms with larger technological distance tend to lag further behind. We test this hypothesis using a unique firm-level data of Chinese...... manufacturing. Our empirical results confirm that foreign entry indeed generates strong heterogeneous growth patterns among domestic firms....

  11. probeBase--an online resource for rRNA-targeted oligonucleotide probes and primers: new features 2016.

    Science.gov (United States)

    Greuter, Daniel; Loy, Alexander; Horn, Matthias; Rattei, Thomas

    2016-01-04

    probeBase http://www.probebase.net is a manually maintained and curated database of rRNA-targeted oligonucleotide probes and primers. Contextual information and multiple options for evaluating in silico hybridization performance against the most recent rRNA sequence databases are provided for each oligonucleotide entry, which makes probeBase an important and frequently used resource for microbiology research and diagnostics. Here we present a major update of probeBase, which was last featured in the NAR Database Issue 2007. This update describes a complete remodeling of the database architecture and environment to accommodate computationally efficient access. Improved search functions, sequence match tools and data output now extend the opportunities for finding suitable hierarchical probe sets that target an organism or taxon at different taxonomic levels. To facilitate the identification of complementary probe sets for organisms represented by short rRNA sequence reads generated by amplicon sequencing or metagenomic analysis with next generation sequencing technologies such as Illumina and IonTorrent, we introduce a novel tool that recovers surrogate near full-length rRNA sequences for short query sequences and finds matching oligonucleotides in probeBase.

  12. Entry Descent and Landing Systems for small planetary missions: parametric comparison of parachutes and inflatable systems for the proposed Vanguard Mars mission

    Science.gov (United States)

    Allouis, E.; Ellery, A.; Welch, C. S.

    2003-11-01

    Here the feasibility of a post-Beagle2 robotic Mars mission of modest size, mass and cost with a high scientific return is assessed. Based on a triad of robotics comprising a lander, a rover and three penetrating moles, the mission is astrobiology focussed, but also provides a platform for technology demonstration. The study is investigating two Entry, Descent and Landing Systems (EDLS) for the 120kg - mission based on the conventional heatshield/parachute duo and on the use of inflatable technologies as demonstrated by the IRDT/IRDT2 projects. Moreover, to make use of existing aerodynamic databases, both EDLS are considered with two geometries: the Mars Pathfinder (MPF) and Huygens/Beagle2 (B2) configurations. A versatile EDL model has been developed to provide a preliminary sizing for the different EDL systems such as heatshield, parachute, and inflatables for small to medium planetary missions. With a landed mass of 65 kg, a preliminary mass is derived for each system of the mission to provide a terminal velocity compatible with the use of airbags. On both conventional and inflatable options, the MPF configuration performs slightly better mass-wise since its cone half-angle is flatter at 70 degrees. Overall, the Inflatable Braking Device (IBD) option performs better than the conventional one and would provide in this particular case a decrease in mass of the EDLS of about 15-18% that can be redistributed to the payload.

  13. Analytic Guidance for the First Entry in a Skip Atmospheric Entry

    Science.gov (United States)

    Garcia-Llama, Eduardo

    2007-01-01

    This paper presents an analytic method to generate a reference drag trajectory for the first entry portion of a skip atmospheric entry. The drag reference, expressed as a polynomial function of the velocity, will meet the conditions necessary to fit the requirements of the complete entry phase. The generic method proposed to generate the drag reference profile is further simplified by thinking of the drag and the velocity as density and cumulative distribution functions respectively. With this notion it will be shown that the reference drag profile can be obtained by solving a linear algebraic system of equations. The resulting drag profile is flown using the feedback linearization method of differential geometric control as guidance law with the error dynamics of a second order homogeneous equation in the form of a damped oscillator. This approach was first proposed as a revisited version of the Space Shuttle Orbiter entry guidance. However, this paper will show that it can be used to fly the first entry in a skip entry trajectory. In doing so, the gains in the error dynamics will be changed at a certain point along the trajectory to improve the tracking performance.

  14. Entry Location and Entry Timing (ELET Decision Model for International Construction Firms

    Directory of Open Access Journals (Sweden)

    Che Maznah Mat Isa

    2014-09-01

    Full Text Available This paper proposes a model for entry location (EL and entry timing (ET decisions to guide construction firms in accessing targeted international markets.  Neglecting to properly choose the right combination of the entry location and entry timing (ELET decisions can lead to poor performance of the firms’ international ventures.  The sampling frame was from the Malaysian construction firms that have undertaken and completed projects abroad.  Survey questionnaires sent to 115 firms registered with Construction Industry Development Board (CIDB Malaysia, operating in more than 50 countries, achieved a 39.1 per cent response rate. Based on a comprehensive statistical analysis of survey data it was found that the mutually inclusive significant factors that influenced the firms’ ELET decisions were: the firm’s ability to assess market signals and opportunities, international experience, financial capacity, competencies and capabilities (project management, specialist expertise and technology, resources (level of knowledge based on research and development, experience in similar works, financial support from the home country banks, technical complexities of projects and availability of funds for projects.  Hence, the present research builds on and extends the literature on the ELET decisions in a more integrated way. Keywords: Entry location, entry timing, resource-based view, international markets, Malaysian construction firms.

  15. Adaptive Deployable Entry and Placement Technology (ADEPT) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The ADEPT Project is developing a mechanically deployable low-ballistic coefficient aeroshell entry system to perform entry descent landing (EDL) functions for...

  16. Design and Simulation Tools for Planetary Atmospheric Entry Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric entry is one of the most critical phases of flight during planetary exploration missions. During the design of an entry vehicle, experimental and...

  17. An Ultrasonographic Periodontal Probe

    Science.gov (United States)

    Bertoncini, C. A.; Hinders, M. K.

    2010-02-01

    Periodontal disease, commonly known as gum disease, affects millions of people. The current method of detecting periodontal pocket depth is painful, invasive, and inaccurate. As an alternative to manual probing, an ultrasonographic periodontal probe is being developed to use ultrasound echo waveforms to measure periodontal pocket depth, which is the main measure of periodontal disease. Wavelet transforms and pattern classification techniques are implemented in artificial intelligence routines that can automatically detect pocket depth. The main pattern classification technique used here, called a binary classification algorithm, compares test objects with only two possible pocket depth measurements at a time and relies on dimensionality reduction for the final determination. This method correctly identifies up to 90% of the ultrasonographic probe measurements within the manual probe's tolerance.

  18. Hard probes 2006 Asilomar

    CERN Multimedia

    2006-01-01

    "The second international conference on hard and electromagnetic probes of high-energy nuclear collisions was held June 9 to 16, 2006 at the Asilomar Conference grounds in Pacific Grove, California" (photo and 1/2 page)

  19. Dependency of radon entry on pressure difference

    Science.gov (United States)

    Kokotti, H.; Kalliokoski, P.; Jantunen, M.

    Radon levels, ventilation rate and pressure differences were monitored continuously in four apartment houses with different ventilation systems. Two of them were ventilated by mechanical exhaust, one by mechanical supply and exhaust, and one by natural ventilation. The two-storey houses were constructed from concrete elements on a slab and located on a gravel esker. It was surprising to find that increasing the ventilation rate increased levels of radon in the apartments. Increased ventilation caused increased outdoor-indoor pressure difference, which in turn increased the entry rate of radon and counteracted the diluting effect of ventilation. The increase was significant when the outdoor-indoor pressure difference exceeded 5 Pa. Especially in the houses with mechanical exhaust ventilation the pressure difference was the most important factor of radon entry rate, and contributed up to several hundred Bq m -3 h -1.

  20. Prototipicality in entries of school dictionaries

    Directory of Open Access Journals (Sweden)

    Everton Castro de Almeida

    2015-01-01

    Full Text Available Theoretical Lexicography is the discipline which, in a general way, studies and criticizes the dictionaries. It is open to the theoretical contribution from other fields of research, such as Text Linguistics, Pragmatics, and Multimodality, once they may show another lexical dimension. Thus, we base our analysis on the theoretical support from Prototypes Theory, from cognitive sciences. In that sense, this paper aims to identify and describe the prototypicality in entries from the five type 3 dictionaries from the PNLD 2012 (National Plan for the Didactic Books. In order to do so, we use theories from Pontes (2008; 2009 and Geeraerts (2007. We analyze five entries, one from each dictionary type 3.

  1. 14 CFR 375.24 - Entry and clearance.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Entry and clearance. 375.24 Section 375.24 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) SPECIAL... Entry and clearance. All U.S. entry and clearance requirements for aircraft, passengers, crews,...

  2. 19 CFR 143.35 - Procedure for electronic entry summary.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Procedure for electronic entry summary. 143.35 Section 143.35 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) SPECIAL ENTRY PROCEDURES Electronic Entry Filing § 143.35...

  3. 77 FR 17492 - Expansion of Global Entry to Additional Airports

    Science.gov (United States)

    2012-03-26

    ... selection process, and the initial airport locations. See 77 FR 5681 and 8 CFR 235.12. Travelers who wish to... SECURITY U.S. Customs and Border Protection Expansion of Global Entry to Additional Airports AGENCY: U.S... as Global Entry, at twenty major U.S. airports. Global Entry allows pre-approved,...

  4. 40 CFR 90.1207 - Entry and access.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Entry and access. 90.1207 Section 90... § 90.1207 Entry and access. (a) To allow the Administrator to determine whether a manufacturer is... maintenance. (c) The provisions of § 90.705(c), (d), (e), (f) and (g) also apply to entry and access...

  5. Maximum Atmospheric Entry Angle for Specified Retrofire Impulse

    Directory of Open Access Journals (Sweden)

    T. N. Srivastava

    1969-07-01

    Full Text Available Maximum atmospheric entry angles for vehicles initially moving in elliptic orbits are investigated and it is shown that tangential retrofire impulse at the apogee results in the maximum entry angle. Equivalence of maximizing the entry angle and minimizing the retrofire impulse is also established.

  6. 19 CFR 143.16 - Substitution of warehouse entry.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Substitution of warehouse entry. 143.16 Section 143.16 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT... warehouse entry. The importer may substitute an entry for warehouse at any time within 1 year from the...

  7. 50 CFR 91.16 - Submission procedures for entry.

    Science.gov (United States)

    2010-10-01

    ... (CONTINUED) MISCELLANEOUS PROVISIONS MIGRATORY BIRD HUNTING AND CONSERVATION STAMP CONTEST Procedures for.... Each entry must be accompanied by a non-refundable entrance fee and a completed and signed Reproduction... the Reproduction Rights Agreement must be attached to the back of the entry. (b) Each entry should...

  8. 31 CFR 337.6 - Conversions to book-entry.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Conversions to book-entry. 337.6... HOUSING ADMINISTRATION DEBENTURES Certificated Debentures § 337.6 Conversions to book-entry. Upon implementation of the book-entry debenture system, to be announced in advance by separate public notice, all...

  9. Sport entries & qualification manual: Innsbruck 2012 Youth Olympic Games

    OpenAIRE

    2015-01-01

    Sport entries constitute an important part of the delegation registration process of the Innsbruck 2012 Winter Youth Olympic Games. This manual aims to introduce to NOCs the process, relevant policies and requirements regarding sport entries so as to ensure that NOCs can successfully complete the entries for their athletes to the Innsbruck 2012 Winter Youth Olympic Games.

  10. Hypersonic Flight Mechanics. [for atmospheric entry trajectories

    Science.gov (United States)

    Busemann, A.; Vinh, N. X.; Culp, R. D.

    1976-01-01

    The effects of aerodynamic forces on trajectories at orbital speeds are discussed in terms of atmospheric models. The assumptions for the model are spherical symmetry, nonrotating, and an exponential atmosphere. The equations of flight, and the performance in extra-atmospheric flight are discussed along with the return to the atmosphere, and the entry. Solutions of the exact equations using directly matched asymptotic expansions are presented.

  11. Unified treatment of lifting atmospheric entry

    Science.gov (United States)

    Nachtsheim, P. R.; Lehman, L. L.

    1980-01-01

    This paper presents a unified treatment of the effect of lift on peak acceleration during atmospheric entry. Earlier studies were restricted to different regimes because of approximations invoked to solve the same transcendental equation. This paper shows the connection between the earlier studies by employing a general expression for the peak acceleration and obtains solutions to the transcendental equation without invoking the earlier approximations. Results are presented and compared with earlier studies where appropriate.

  12. Nuclear Chk1 prevents premature mitotic entry.

    Science.gov (United States)

    Matsuyama, Makoto; Goto, Hidemasa; Kasahara, Kousuke; Kawakami, Yoshitaka; Nakanishi, Makoto; Kiyono, Tohru; Goshima, Naoki; Inagaki, Masaki

    2011-07-01

    Chk1 inhibits the premature activation of the cyclin-B1-Cdk1. However, it remains controversial whether Chk1 inhibits Cdk1 in the centrosome or in the nucleus before the G2-M transition. In this study, we examined the specificity of the mouse monoclonal anti-Chk1 antibody DCS-310, with which the centrosome was stained. Conditional Chk1 knockout in mouse embryonic fibroblasts reduced nuclear but not centrosomal staining with DCS-310. In Chk1(+/myc) human colon adenocarcinoma (DLD-1) cells, Chk1 was detected in the nucleus but not in the centrosome using an anti-Myc antibody. Through the combination of protein array and RNAi technologies, we identified Ccdc-151 as a protein that crossreacted with DCS-310 on the centrosome. Mitotic entry was delayed by expression of the Chk1 mutant that localized in the nucleus, although forced immobilization of Chk1 to the centrosome had little impact on the timing of mitotic entry. These results suggest that nuclear but not centrosomal Chk1 contributes to correct timing of mitotic entry.

  13. Cell entry by human pathogenic arenaviruses.

    Science.gov (United States)

    Rojek, Jillian M; Kunz, Stefan

    2008-04-01

    The arenaviruses Lassa virus (LASV) in Africa and Machupo (MACV), Guanarito (GTOV) and Junin viruses (JUNV) in South America cause severe haemorrhagic fevers in humans with fatality rates of 15-35%. The present review focuses on the first steps of infection with human pathogenic arenaviruses, the interaction with their cellular receptor molecules and subsequent entry into the host cell. While similarities exist in genomic organization, structure and clinical disease caused by pathogenic Old World and New World arenaviruses these pathogens use different primary receptors. The Old World arenaviruses employ alpha-dystroglycan, a cellular receptor for proteins of the extracellular matrix, and the human pathogenic New World arenaviruses use the cellular cargo receptor transferrin receptor 1. While the New World arenavirus JUNV enters cells via clathrin-dependent endocytosis, evidence occurred for clathrin-independent entry of the prototypic Old World arenavirus lymphocytic choriomeningitis virus. Upon internalization, arenaviruses are delivered to the endosome, where pH-dependent membrane fusion is mediated by the envelope glycoprotein (GP). While arenavirus GPs share characteristics with class I fusion GPs of other enveloped viruses, unusual mechanistic features of GP-mediated membrane fusion have recently been discovered for arenaviruses with important implications for viral entry.

  14. Kinetics of virus entry by endocytosis

    Science.gov (United States)

    Zhdanov, Vladimir P.

    2015-04-01

    Entry of virions into the host cells is either endocytotic or fusogenic. In both cases, it occurs via reversible formation of numerous relatively weak bonds resulting in wrapping of a virion by the host membrane with subsequent membrane rupture or scission. The corresponding kinetic models are customarily focused on the formation of bonds and do not pay attention to the energetics of the whole process, which is crucially dependent, especially in the case of endocytosis, on deformation of actin filaments forming the cytoskeleton of the host cell. The kinetic model of endocytosis, proposed by the author, takes this factor into account and shows that the whole process can be divided into a rapid initial transient stage and a long steady-state stage. The entry occurs during the latter stage and can be described as a first-order reaction. Depending on the details of the dependence of the grand canonical potential on the number of bonds, the entry can be limited either by the interplay of bond formation and membrane rupture (or scission) or by reaching a maximum of this potential.

  15. Filovirus tropism: Cellular molecules for viral entry

    Directory of Open Access Journals (Sweden)

    Ayato eTakada

    2012-02-01

    Full Text Available In human and nonhuman primates, filoviruses (Ebola and Marburg viruses cause severe hemorrhagic fever.Recently, other animals such as pigs and some species of fruit bats have also been shown to be susceptible to these viruses. While having a preference for some cell types such as hepatocytes, endothelial cells, dendritic cells, monocytes, and macrophages, filoviruses are known to be pantropic in infection of primates. The envelope glycoprotein (GP is responsible for both receptor binding and fusion of the virus envelope with the host cell membrane. It has been demonstrated that filovirus GP interacts with multiple molecules for entry into host cells, whereas none of the cellular molecules so far identified as a receptor/coreceptor fully explains filovirus tissue tropism and host range. Available data suggest that the mucin-like region (MLR on GP plays an important role in attachment to the preferred target cells, whose infection is likely involved in filovirus pathogenesis, whereas the MLR is not essential for the fundamental function of the GP in viral entry into cells in vitro. Further studies elucidating the mechanisms of cellular entry of filoviruses may shed light on the development of strategies for prophylaxis and treatment of Ebola and Marburg hemorrhagic fevers.

  16. 19 CFR 149.6 - Entry and entry summary documentation and Importer Security Filing submitted via a single...

    Science.gov (United States)

    2010-04-01

    ... Security Filing submitted via a single electronic transmission. 149.6 Section 149.6 Customs Duties U.S... submitted via a single electronic transmission. If the Importer Security Filing is filed pursuant to § 149.2 of this part via the same electronic transmission as entry or entry/entry summary...

  17. Entry and Exit Dynamics of Nascent Business Owners

    DEFF Research Database (Denmark)

    Rocha, Vera; Carneiro, Anabela; Varum, Celeste

    2015-01-01

    in the labor market and entry modes shape the post-entry dynamics of nascent business owners. By differentiating between different entry and exit routes, this paper provides new evidence on different human capital patterns among nascent business owners and on key determinants of entrepreneurial survival. Our...... results suggest that different exit modes can be predicted by business owners’ entry route. Furthermore, different exit modes exhibit different duration dependence patterns according to the entry mode. Additionally, the paper shows that businesses started after a displacement episode are not necessarily...

  18. Exporting Complex Digital Products: Motives and Entry Modes

    DEFF Research Database (Denmark)

    Rask, Morten

    2005-01-01

    for digital product providers. However, other types of entry modes like what we call direct digital export with F2F-sales, direct digital export with F2F-support, and virtual sales subsidiary are entry modes that respond to a higher degree of pre- and postsales complexity.......When the product is digital, it will most often be distributed directly to the customer through the Internet, and therefore, the entry modes, considered in this paper, are different flavors of the entry mode called direct export: virtual export channel is generally understood as the entry mode...

  19. Exporting Complex Digital Products: Motives and Entry Modes

    DEFF Research Database (Denmark)

    Rask, Morten

    for digital product providers. However other types of entry modes like what wee call direct digital export with F2F-sales, direct digital export with F2F-support and virtual sales subsidiary are entry modes that respond to a higher degree of pre- and after-sales complexity.......When the product is digital, it will most often be distributed directly to the customer through the Internet, and therefore the entry modes, considered in this paper, are different flavors of the entry mode called direct export: Virtual export channel are generally understood as the entry mode...

  20. Exporting Complex Digital Products: Motives and Entry Modes

    DEFF Research Database (Denmark)

    Rask, Morten

    When the product is digital, it will most often be distributed directly to the customer through the Internet, and therefore the entry modes, considered in this paper, are different flavors of the entry mode called direct export: Virtual export channel are generally understood as the entry mode...... for digital product providers. However other types of entry modes like what wee call direct digital export with F2F-sales, direct digital export with F2F-support and virtual sales subsidiary are entry modes that respond to a higher degree of pre- and after-sales complexity....

  1. Exporting Complex Digital Products: Motives and Entry Modes

    DEFF Research Database (Denmark)

    Rask, Morten

    2005-01-01

    When the product is digital, it will most often be distributed directly to the customer through the Internet, and therefore, the entry modes, considered in this paper, are different flavors of the entry mode called direct export: virtual export channel is generally understood as the entry mode...... for digital product providers. However, other types of entry modes like what we call direct digital export with F2F-sales, direct digital export with F2F-support, and virtual sales subsidiary are entry modes that respond to a higher degree of pre- and postsales complexity....

  2. Assessment of the ATV-1 Re-Entry Observation Campaign for Future Re-Entry Missions

    Science.gov (United States)

    Lips, T.; Lohle, S.; Marynowsky, T.; Rees, D.; Stenbeak-Nielsen, H. C.; Beks, M. L.; Hatton, J.

    2010-09-01

    This paper summarizes the midterm results of the currently ongoing ESA study “Assessment of the ATV-1 Reentry Observation Campaign for Future Re-entry Missions”. The primary objective of this study is to investigate the data obtained during a joint ESA/NASA airborne observation campaign of the destructive re-entry of ATV-1 Jules Verne which occurred on September 29, 2008. The presented results are focused on spectroscopic fragment characterization(material identification), frame-by-frame fragment tracking(manual and automatic) for various video recordings, 3D triangulation of the tracked fragments, and fragment propagation until complete demise or ground impact, including the actual size and location of the ATV-1 debris footprint. Fragment propagation analyses comprise also the derivation of aerodynamic fragment properties and potential delta velocities. These parameters are of high importance for the re-entry safety analysis for ATV-2 Johannes Kepler.

  3. Entry properties and entry inhibitors of a human H7N9 influenza virus.

    Directory of Open Access Journals (Sweden)

    Youhui Si

    Full Text Available The recently identified human infections with a novel avian influenza H7N9 virus in China raise important questions regarding possible risk to humans. However, the entry properties and tropism of this H7N9 virus were poorly understood. Moreover, neuraminidase inhibitor resistant H7N9 isolates were recently observed in two patients and correlated with poor clinical outcomes. In this study, we aimed to elucidate the entry properties of H7N9 virus, design and evaluate inhibitors for H7N9 virus entry. We optimized and developed an H7N9-pseudotyped particle system (H7N9pp that could be neutralized by anti-H7 antibodies and closely mimicked the entry process of the H7N9 virus. Avian, human and mouse-derived cultured cells showed high, moderate and low permissiveness to H7N9pp, respectively. Based on influenza virus membrane fusion mechanisms, a potent anti-H7N9 peptide (P155-185-chol corresponding to the C-terminal ectodomain of the H7N9 hemagglutinin protein was successfully identified. P155-185-chol demonstrated H7N9pp-specific inhibition of infection with IC50 of 0.19 µM. Importantly, P155-185-chol showed significant suppression of A/Anhui/1/2013 H7N9 live virus propagation in MDCK cells and additive effects with NA inhibitors Oseltamivir and Zanamivir. These findings expand our knowledge of the entry properties of the novel H7N9 viruses, and they highlight the potential for developing a new class of inhibitors targeting viral entry for use in the next pandemic.

  4. Entry Properties and Entry Inhibitors of a Human H7N9 Influenza Virus

    OpenAIRE

    Youhui Si; Jianguo Li; Yuqiang Niu; Xiuying Liu; Lili Ren; Li Guo; Min Cheng; Hongli Zhou; Jianwei Wang; Qi Jin; Wei Yang

    2014-01-01

    The recently identified human infections with a novel avian influenza H7N9 virus in China raise important questions regarding possible risk to humans. However, the entry properties and tropism of this H7N9 virus were poorly understood. Moreover, neuraminidase inhibitor resistant H7N9 isolates were recently observed in two patients and correlated with poor clinical outcomes. In this study, we aimed to elucidate the entry properties of H7N9 virus, design and evaluate inhibitors for H7N9 virus e...

  5. Influence of nonequilibrium radiation and shape change on aerothermal environment of a Jovian entry body

    Science.gov (United States)

    Tiwari, S. N.; Subramanian, S. V.

    1981-01-01

    The influence of nonequilibrium radiative energy transfer and the effect of probe configuration changes on the flow phenomena around a Jovian entry body are investigated. The radiating shock layer flow is assumed to be axisymmetric, viscous, laminar and in chemical equilibrium. The radiative transfer equations are derived under nonequilibrium conditions which include multilevel energy transitions. The equilibrium radiative transfer analysis is performed with an existing nongray radiation model which accounts for molecular band, atomic line, and continuum transitions. The nonequilibrium results are obtained with and without ablation injection in the shock layer. The nonequilibrium results are found to be greatly influenced by the temperature distribution in the shock layer. In the absence of ablative products, the convective and radiative heating to the entry body are reduced under nonequilibrium conditions. The influence of nonequilibrium is found to be greater at higher entry altitudes. With coupled ablation and carbon phenolic injection, 16 chemical species are used in the ablation layer for radiation absorption. Equilibrium and nonequilibrium results are compared under peak heating conditions.

  6. GPK-2 re-entry and deepening -- a technical report

    Energy Technology Data Exchange (ETDEWEB)

    Baumgartner, J.; Gerard, A.; Barla, R.; Socomine, S.A.

    1999-01-01

    Between mid February to end of May 1999 (in 104 days) the well GPK2 at the Soultz HDR site was successfully re-entered and deepened from 3876 m to a final depth of 5084 m and fully completed. Re-entry included the pulling of the existing 321 1 m long internal 9 5/8-inch by 7-inch casing string, fishing of a submersible pump and some 150 m of 2 3/8-inch tubing, sealing of a major loss zone and opening of a 6 1/4-inch well section in granite (3211-3876 m) to 8 1/2-inch hole size. The well was extended to 5048 m in 8 1/2'' hole size and again completed with a floating 9 5/8-inch by 7-inch casing string. The casing shoe is at 4431 m. A bottom hole core was taken in the depth range 5048-5051 m. The core recovery was app. 40%. A pilot hole in 6 1/4-inch was drilled from 5051-5084 m for in situ stress measurements using the hydraulic fracturing technique. The re-entry and deepening of the well GPK2 was accompanied by several technical developments. New casing packer elements based on inflatable metal shells were developed in a close cooperation between SOCOMINE and MeSy GmbH (patent pending). These packer elements were successfully integrated into the completion of the well. The full weight of the casing string is supported by these elements which are filled with and imbedded in cement. High temperature cementing strategies (up to 170-190 C) for the complex saline fluids encountered in Soultz (High Magnesium Resistant Cements) were developed in a cooperation between Schlumberger Dowell (Vechta), SOCOMINE, SII of Houston, Ruhr-University Bochum, BGR Hannover and IFP Paris. The development of several high temperature logging tools (200 C range, 6-arm caliper, PTF probe) was initiated with CSMA (Cornwall) during the preparation of the deepening of GPK2. Initial scientific investigations included borehole logging (NGS, CLIPER, ARI, UBI, TEMPERATURE), geological investigations (cuttings, core) and seismic monitoring while drilling. During the first temperature log

  7. A Dual Microscopy-Based Assay To Assess Listeria monocytogenes Cellular Entry and Vacuolar Escape.

    Science.gov (United States)

    Quereda, Juan J; Pizarro-Cerdá, Javier; Balestrino, Damien; Bobard, Alexandre; Danckaert, Anne; Aulner, Nathalie; Shorte, Spencer; Enninga, Jost; Cossart, Pascale

    2015-10-23

    Listeria monocytogenes is a Gram-positive bacterium and a facultative intracellular pathogen that invades mammalian cells, disrupts its internalization vacuole, and proliferates in the host cell cytoplasm. Here, we describe a novel image-based microscopy assay that allows discrimination between cellular entry and vacuolar escape, enabling high-content screening to identify factors specifically involved in these two steps. We first generated L. monocytogenes and Listeria innocua strains expressing a β-lactamase covalently attached to the bacterial cell wall. These strains were then incubated with HeLa cells containing the Förster resonance energy transfer (FRET) probe CCF4 in their cytoplasm. The CCF4 probe was cleaved by the bacterial surface β-lactamase only in cells inoculated with L. monocytogenes but not those inoculated with L. innocua, thereby demonstrating bacterial access to the host cytoplasm. Subsequently, we performed differential immunofluorescence staining to distinguish extracellular versus total bacterial populations in samples that were also analyzed by the FRET-based assay. With this two-step analysis, bacterial entry can be distinguished from vacuolar rupture in a single experiment. Our novel approach represents a powerful tool for identifying factors that determine the intracellular niche of L. monocytogenes.

  8. Influence of nonequilibrium radiation and shape change on aerothermal environment of Jovian entry body

    Science.gov (United States)

    Tiwari, S. N.; Subramanian, S. V.

    1980-01-01

    Radiative transfer equations are derived under nonequilibrium conditions which include multilevel energy transitions. The nonequalibrium results, obtained with and without ablation injection in the shock layer, are found to be greatly influenced by the temperature distribution in the shock layer. In the absence of ablative products, the convective and radiative heating to the entry body are reduced significantly under nonequilibrium conditions. The influence of nonequilibrium is found to be greater at higher entry altitudes. With coupled ablation and carbon phenolic injection, 16 chemical species are used in the ablation layer for radiation absorption. Equilibrium and nonequilibrium results are compared under peak heating conditions. A 45 degree sphere cone, a 35 degree hyperboloid, and a 45 degree ellipsoid were used to study probe shape change. Results indicate that the shock layer flow field and heat transfer to the body are influenced significantly by the probe shape change. The effect of shape change on radiative heating of the afterbodies is found to be considerably larger for the sphere cone and ellipsoid than for the hyperboloid.

  9. Access, entry and researcher-participant position

    DEFF Research Database (Denmark)

    Louw, Arnt Vestergaard

    2015-01-01

    it deals with the research findings that such a research design produced. As well as the methodological issues of researcher access, entry and participant position in the field, this article reports on the following questions: What kinds of implicit expectations of the students are embedded in the way...... the school introduces and initiates the programme? What kinds of effects does this have on the motivation of the students? How do the terms and professional language of the profession work on the individual students in including and excluding ways? These specific descriptions of classroom pedagogy, inspired...

  10. Radiation Database for Earth and Mars Entry

    Science.gov (United States)

    2008-11-17

    d3Πg − a3Πu (0:18;0:33) Fox- Herzberg e3Πg − a3Πu (0:15;0:35) Radiation Database for Earth and Mars Entry RTO-EN-AVT-162 8 - 15 affect a few J...structures of the spectra, namely in lines. This motivates the development of approximate models which do not have the high resolution structures but provide...Dec 1996. [2] L.C. Hartung. Predicting radiative heat transfer in thermo-chemical non-equilibrium flow- fields: theory and user’s manual for the

  11. Evolved Acceleration Guidance for Planetary Entry

    Science.gov (United States)

    Mease, K. D.; Leavitt, J. A.; Ferch, M.

    The U.S. Apollo and Shuttle programs have proven the viability and effectiveness of acceleration guidance. New capabilities have been developed to augment this basic concept. Algorithms have been designed for low lift to drag ratio vehicles and for mid to high lift to drag ratio vehicles. These algorithms have been tested for Mars landing and for earth entry of reusable launch vehicles and have performed well in both cases. Also the trajectory planner has been incorporated into a landing footprint generator that is designed for on-board use.

  12. Reference pricing with endogenous generic entry.

    OpenAIRE

    Kurt R. Brekke; Canta, Chiara; Straume, Odd Rune

    2015-01-01

    In this paper we study the effect of reference pricing on pharmaceutical prices and ex-penditures when generic entry is endogenously determined. We develop a Salop-type model where a brand-name producer competes with generic producers in terms of prices. In the market there are two types of consumers: (i) brand biased consumers who choose between brand-name and generic drugs, and (ii) brand neutral consumers who choose between the different generic drugs. We find that, for a given number of ...

  13. Female entrepreneurial networks and foreign market entry

    DEFF Research Database (Denmark)

    Rosenbaum, Gitte Ohrt

    2017-01-01

    The purpose of this paper is to explore the role of networks in the 116 foreign market entries (FMEs) of women-owned small businesses. A multiple case study based on semi-structured interviews with eight female entrepreneurs in the Danish fashion design industry. The results show that contrary to...... entrepreneurial ventures....... or compromising their work-life balance. The present study’s findings suggest that ICT has a much stronger role in the FME of firms than previously envisioned. The study’s findings also have important implications for policymakers and practitioners charged with promoting the international growth of female...

  14. Hard Probes at ATLAS

    CERN Document Server

    Citron, Z; The ATLAS collaboration

    2014-01-01

    The ATLAS collaboration has measured several hard probe observables in Pb+Pb and p+Pb collisions at the LHC. These measurements include jets which show modification in the hot dense medium of heavy ion collisions as well as color neutral electro-weak bosons. Together, they elucidate the nature of heavy ion collisions.

  15. Endocavity Ultrasound Probe Manipulators.

    Science.gov (United States)

    Stoianovici, Dan; Kim, Chunwoo; Schäfer, Felix; Huang, Chien-Ming; Zuo, Yihe; Petrisor, Doru; Han, Misop

    2013-06-01

    We developed two similar structure manipulators for medical endocavity ultrasound probes with 3 and 4 degrees of freedom (DoF). These robots allow scanning with ultrasound for 3-D imaging and enable robot-assisted image-guided procedures. Both robots use remote center of motion kinematics, characteristic of medical robots. The 4-DoF robot provides unrestricted manipulation of the endocavity probe. With the 3-DoF robot the insertion motion of the probe must be adjusted manually, but the device is simpler and may also be used to manipulate external-body probes. The robots enabled a novel surgical approach of using intraoperative image-based navigation during robot-assisted laparoscopic prostatectomy (RALP), performed with concurrent use of two robotic systems (Tandem, T-RALP). Thus far, a clinical trial for evaluation of safety and feasibility has been performed successfully on 46 patients. This paper describes the architecture and design of the robots, the two prototypes, control features related to safety, preclinical experiments, and the T-RALP procedure.

  16. One-Probe Search

    DEFF Research Database (Denmark)

    Östlin, Anna; Pagh, Rasmus

    2002-01-01

    We consider dictionaries that perform lookups by probing a single word of memory, knowing only the size of the data structure. We describe a randomized dictionary where a lookup returns the correct answer with probability 1 - e, and otherwise returns don't know. The lookup procedure uses an expan...

  17. Probing the Solar System

    Science.gov (United States)

    Wilkinson, John

    2013-01-01

    Humans have always had the vision to one day live on other planets. This vision existed even before the first person was put into orbit. Since the early space missions of putting humans into orbit around Earth, many advances have been made in space technology. We have now sent many space probes deep into the Solar system to explore the planets and…

  18. One-Probe Search

    DEFF Research Database (Denmark)

    Östlin, Anna; Pagh, Rasmus

    2002-01-01

    We consider dictionaries that perform lookups by probing a single word of memory, knowing only the size of the data structure. We describe a randomized dictionary where a lookup returns the correct answer with probability 1 - e, and otherwise returns don't know. The lookup procedure uses an expan...

  19. Probing the Solar System

    Science.gov (United States)

    Wilkinson, John

    2013-01-01

    Humans have always had the vision to one day live on other planets. This vision existed even before the first person was put into orbit. Since the early space missions of putting humans into orbit around Earth, many advances have been made in space technology. We have now sent many space probes deep into the Solar system to explore the planets and…

  20. 77 FR 72715 - Informal Entry Limit and Removal of a Formal Entry Requirement

    Science.gov (United States)

    2012-12-06

    ... increase of the informal entry limit is also consistent with one of the goals of the Beyond the Border... the policy seemed inconsistent with the recent Congressional decision to increase the ad valorem MPFs... this analysis, CBP cannot ascertain with any degree of certainty the specific monetary impacts...

  1. Entry, Descent, and Landing Operations Analysis for the Genesis Entry Capsule

    Science.gov (United States)

    Desai, Prasun N.; Lyons, Daniel T.

    2007-01-01

    On September 8, 2004, the Genesis spacecraft returned to Earth after spending 29 months about the sun-Earth libration point (L1) collecting solar wind particles. Four hours prior to Earth arrival, the sample return capsule containing the samples was released for entry and subsequent landing at the Utah Test and Training Range. This paper provides an overview of the entry, descent, and landing trajectory analysis that was performed during the mission operations phase leading up to final approach to Earth. The final orbit determination solution produced an inertial entry flight-path angle of -8.002 deg (which was the desired nominal value) with a 3-sigma error of +/-0.0274 deg (a third of the requirement). The operations effort accurately delivered the entry capsule to the desired landing site. The final landing location was 8.3 km from the target, and was well within the allowable landing area. Overall, the Earth approach operation procedures worked well and there were no issues (logistically or performance based) that arose. As a result, the process of targeting a capsule from deep space and accurately landing it on Earth was successfully demonstrated.

  2. Mycobacteria entry and trafficking into endothelial cells.

    Science.gov (United States)

    Baltierra-Uribe, Shantal Lizbeth; García-Vásquez, Manuel de Jesús; Castrejón-Jiménez, Nayeli Shantal; Estrella-Piñón, Mayra Patricia; Luna-Herrera, Julieta; García-Pérez, Blanca Estela

    2014-09-01

    Endothelial cells are susceptible to infection by mycobacteria, but the endocytic mechanisms that mycobacteria exploit to enter host cells and their mechanisms of intracellular transport are completely unknown. Using pharmacological inhibitors, we determined that the internalization of Mycobacterium tuberculosis (MTB), Mycobacterium smegmatis (MSM), and Mycobacterium abscessus (MAB) is dependent on the cytoskeleton and is differentially inhibited by cytochalasin D, nocodazole, cycloheximide, wortmannin, and amiloride. Using confocal microscopy, we investigated their endosomal trafficking by analyzing Rab5, Rab7, LAMP-1, and cathepsin D. Our results suggest that MSM exploits macropinocytosis to enter endothelial cells and that the vacuoles containing these bacteria fuse with lysosomes. Conversely, the entry of MTB seems to depend on more than one endocytic route, and the observation that only a subset of the intracellular bacilli was associated with phagolysosomes suggests that these bacteria are able to inhibit endosomal maturation to persist intracellularly. The route of entry for MAB depends mainly on microtubules, which suggests that MAB uses a different trafficking pathway. However, MAB is also able to inhibit endosomal maturation and can replicate intracellularly. Together, these findings provide the first evidence that mycobacteria modulate proteins of host endothelial cells to enter and persist within these cells.

  3. Text Entry by Gazing and Smiling

    Directory of Open Access Journals (Sweden)

    Outi Tuisku

    2013-01-01

    Full Text Available Face Interface is a wearable prototype that combines the use of voluntary gaze direction and facial activations, for pointing and selecting objects on a computer screen, respectively. The aim was to investigate the functionality of the prototype for entering text. First, three on-screen keyboard layout designs were developed and tested (n=10 to find a layout that would be more suitable for text entry with the prototype than traditional QWERTY layout. The task was to enter one word ten times with each of the layouts by pointing letters with gaze and select them by smiling. Subjective ratings showed that a layout with large keys on the edge and small keys near the center of the keyboard was rated as the most enjoyable, clearest, and most functional. Second, using this layout, the aim of the second experiment (n=12 was to compare entering text with Face Interface to entering text with mouse. The results showed that text entry rate for Face Interface was 20 characters per minute (cpm and 27 cpm for the mouse. For Face Interface, keystrokes per character (KSPC value was 1.1 and minimum string distance (MSD error rate was 0.12. These values compare especially well with other similar techniques.

  4. Structural correlates of rotavirus cell entry.

    Directory of Open Access Journals (Sweden)

    Aliaa H Abdelhakim

    2014-09-01

    Full Text Available Cell entry by non-enveloped viruses requires translocation into the cytosol of a macromolecular complex--for double-strand RNA viruses, a complete subviral particle. We have used live-cell fluorescence imaging to follow rotavirus entry and penetration into the cytosol of its ∼ 700 Å inner capsid particle ("double-layered particle", DLP. We label with distinct fluorescent tags the DLP and each of the two outer-layer proteins and track the fates of each species as the particles bind and enter BSC-1 cells. Virions attach to their glycolipid receptors in the host cell membrane and rapidly become inaccessible to externally added agents; most particles that release their DLP into the cytosol have done so by ∼ 10 minutes, as detected by rapid diffusional motion of the DLP away from residual outer-layer proteins. Electron microscopy shows images of particles at various stages of engulfment into tightly fitting membrane invaginations, consistent with the interpretation that rotavirus particles drive their own uptake. Electron cryotomography of membrane-bound virions also shows closely wrapped membrane. Combined with high resolution structural information about the viral components, these observations suggest a molecular model for membrane disruption and DLP penetration.

  5. Analytic Development of a Reference Profile for the First Entry in a Skip Atmospheric Entry

    Science.gov (United States)

    Garcia-Llama, Eduardo

    2010-01-01

    This note shows that a feasible reference drag profile for the first entry portion of a skip entry can be generated as a polynomial expression of the velocity. The coefficients of that polynomial are found through the resolution of a system composed of m + 1 equations, where m is the degree of the drag polynomial. It has been shown that a minimum of five equations (m = 4) are required to establish the range and the initial and final conditions on velocity and flight path angle. It has been shown that at least one constraint on the trajectory can be imposed through the addition of one extra equation in the system, which must be accompanied by the increase in the degree of the drag polynomial. In order to simplify the resolution of the system of equations, the drag was considered as being a probability density function of the velocity, with the velocity as a distribution function of the drag. Combining this notion with the introduction of empirically derived constants, it has been shown that the system of equations required to generate the drag profile can be successfully reduced to a system of linear algebraic equations. For completeness, the resulting drag profiles have been flown using the feedback linearization method of differential geometric control as a guidance law with the error dynamics of a second order homogeneous equation in the form of a damped oscillator. Satisfactory results were achieved when the gains in the error dynamics were changed at a certain point along the trajectory that is dependent on the velocity and the curvature of the drag as a function of the velocity. Future work should study the capacity to update the drag profile in flight when dispersions are introduced. Also, future studies should attempt to link the first entry, as presented and controlled in this note, with a more standard control concept for the second entry, such as the Apollo entry guidance, to try to assess the overall skip entry performance. A guidance law that includes

  6. Orthopoxvirus species and strain differences in cell entry

    Energy Technology Data Exchange (ETDEWEB)

    Bengali, Zain; Satheshkumar, P.S. [Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-3210 (United States); Moss, Bernard, E-mail: bmoss@nih.gov [Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-3210 (United States)

    2012-11-25

    Vaccinia virus (VACV) enters cells by a low pH endosomal route or by direct fusion with the plasma membrane. We previously found differences in entry properties of several VACV strains: entry of WR was enhanced by low pH, reduced by bafilomycin A1 and relatively unaffected by heparin, whereas entry of IHD-J, Copenhagen and Elstree were oppositely affected. Since binding and entry modes may have been selected by specific conditions of in vitro propagation, we now examined the properties of three distinct, recently isolated cowpox viruses and a monkeypox virus as well as additional VACV and cowpox virus strains. The recent isolates were more similar to WR than to other VACV strains, underscoring the biological importance of endosomal entry by orthopoxviruses. Sequence comparisons, gene deletions and gene swapping experiments indicated that viral determinants, other than or in addition to the A26 and A25 'fusion-suppressor' proteins, impact entry properties.

  7. Mid-L/D Lifting Body Entry Demise Analysis

    Science.gov (United States)

    Ling, Lisa

    2017-01-01

    The mid-lift-to-drag ratio (mid-L/D) lifting body is a fully autonomous spacecraft under design at NASA for enabling a rapid return of scientific payloads from the International Space Station (ISS). For contingency planning and risk assessment for the Earth-return trajectory, an entry demise analysis was performed to examine three potential failure scenarios: (1) nominal entry interface conditions with loss of control, (2) controlled entry at maximum flight path angle, and (3) controlled entry at minimum flight path angle. The objectives of the analysis were to predict the spacecraft breakup sequence and timeline, determine debris survival, and calculate the debris dispersion footprint. Sensitivity analysis was also performed to determine the effect of the initial pitch rate on the spacecraft stability and breakup during the entry. This report describes the mid-L/D lifting body and presents the results of the entry demise and sensitivity analyses.

  8. EDITORIAL: Probing the nanoworld Probing the nanoworld

    Science.gov (United States)

    Miles, Mervyn

    2009-10-01

    In nanotechnology, it is the unique properties arising from nanometre-scale structures that lead not only to their technological importance but also to a better understanding of the underlying science. Over the last twenty years, material properties at the nanoscale have been dominated by the properties of carbon in the form of the C60 molecule, single- and multi-wall carbon nanotubes, nanodiamonds, and recently graphene. During this period, research published in the journal Nanotechnology has revealed the amazing mechanical properties of such materials as well as their remarkable electronic properties with the promise of new devices. Furthermore, nanoparticles, nanotubes, nanorods, and nanowires from metals and dielectrics have been characterized for their electronic, mechanical, optical, chemical and catalytic properties. Scanning probe microscopy (SPM) has become the main characterization technique and atomic force microscopy (AFM) the most frequently used SPM. Over the past twenty years, SPM techniques that were previously experimental in nature have become routine. At the same time, investigations using AFM continue to yield impressive results that demonstrate the great potential of this powerful imaging tool, particularly in close to physiological conditions. In this special issue a collaboration of researchers in Europe report the use of AFM to provide high-resolution topographical images of individual carbon nanotubes immobilized on various biological membranes, including a nuclear membrane for the first time (Lamprecht C et al 2009 Nanotechnology 20 434001). Other SPM developments such as high-speed AFM appear to be making a transition from specialist laboratories to the mainstream, and perhaps the same may be said for non-contact AFM. Looking to the future, characterisation techniques involving SPM and spectroscopy, such as tip-enhanced Raman spectroscopy, could emerge as everyday methods. In all these advanced techniques, routinely available probes will

  9. Aspirin inhibits hepatitis C virus entry by downregulating claudin-1.

    Science.gov (United States)

    Yin, P; Zhang, L

    2016-01-01

    Aspirin has previously been reported to inhibit hepatitis C virus (HCV) replication. The aim of this study was to investigate whether aspirin is involved in blocking HCV entry. We found that aspirin inhibits the entry of HCVpp and infectious HCV. The level of claudin-1, an HCV receptor, is reduced by aspirin. Our results extend the anti-HCV effect of aspirin to the HCV entry step and further reinforce the anti-HCV role of aspirin.

  10. Methodological aspects of journaling a dynamic adjusting entry model

    Directory of Open Access Journals (Sweden)

    Vlasta Kašparovská

    2011-01-01

    Full Text Available This paper expands the discussion of the importance and function of adjusting entries for loan receivables. Discussion of the cyclical development of adjusting entries, their negative impact on the business cycle and potential solutions has intensified during the financial crisis. These discussions are still ongoing and continue to be relevant to members of the professional public, banking regulators and representatives of international accounting institutions. The objective of this paper is to evaluate a method of journaling dynamic adjusting entries under current accounting law. It also expresses the authors’ opinions on the potential for consistently implementing basic accounting principles in journaling adjusting entries for loan receivables under a dynamic model.

  11. An Integrated Approach for Entry Mission Design and Flight Simulations

    Science.gov (United States)

    Lu, Ping; Rao, Prabhakara

    2004-01-01

    An integrated approach for entry trajectory design, guidance, and simulation is proposed. The key ingredients for this approach are an on-line 3 degree-of-freedom entry trajectory planning algorithm and the entry guidance algorithm that generates the guidance gains automatically. When fully developed, such a tool could enable end-bend entry mission design and simulations in 3DOF and 6DOF mode from de-orbit burn to the TAEM interface and beyond, all in one key stroke. Some preliminary examples of such a capability are presented in this paper that demonstrate the potential of this type of integrated environment.

  12. A novel peptide that inhibits HIV-1 entry

    Institute of Scientific and Technical Information of China (English)

    YU Yong; HUANG Xiaoxing; WANG Qiong; YANG Yaling; TIAN Po; ZHANG Wentao

    2004-01-01

    @@ The global epidemic of HIV infection, the cause of AIDS, has created an urgent need for novel classes of antiretroviral agent. Besides reverse transcriptase and protease, the viral entry process provides new anti-HIV-1 targets. A new generation of antiviral drugs intended to block HIV entry into host cells is now under develop- ment[1]. These compounds are generally referred to as fusion or entry inhibitor. Several HIV-1 entry inhibitors that target CD4-gp120 interactions, co-receptor function, and gp41-mediated membrane fusion are in different stages of clinical development[2].

  13. Protease Inhibitors Targeting Coronavirus and Filovirus Entry

    Science.gov (United States)

    Zhou, Yanchen; Vedantham, Punitha; Lu, Kai; Agudelo, Juliet; Carrion, Ricardo; Nunneley, Jerritt W.; Barnard, Dale; Pöhlmann, Stefan; McKerrow, James H.; Renslo, Adam R.; Simmons, Graham

    2016-01-01

    In order to gain entry into cells, diverse viruses, including Ebola virus, SARS-coronavirus and the emerging MERS-coronavirus, depend on activation of their envelope glycoproteins by host cell proteases. The respective enzymes are thus excellent targets for antiviral intervention. In cell culture, activation of Ebola virus, as well as SARS- and MERS-coronavirus can be accomplished by the endosomal cysteine proteases, cathepsin L (CTSL) and cathepsin B (CTSB). In addition, SARS- and MERS-coronavirus can use serine proteases localized at the cell surface, for their activation. However, it is currently unclear which protease(s) facilitate viral spread in the infected host. We report here that the cysteine protease inhibitor K11777, ((2S)-N-[(1E,3S)-1-(benzenesulfonyl)-5-phenylpent-1-en-3-yl]-2-{[(E)-4-methylpiperazine-1-carbonyl]amino}-3-phenylpropanamide) and closely-related vinylsulfones act as broad-spectrum antivirals by targeting cathepsin-mediated cell entry. K11777 is already in advanced stages of development for a number of parasitic diseases, such as Chagas disease, and has proven to be safe and effective in a range of animal models. K11777 inhibition of SARS-CoV and Ebola virus entry was observed in the sub-nanomolar range. In order to assess, whether cysteine or serine proteases promote viral spread in the host, we compared the antiviral activity of an optimized K11777-derivative with that of camostat, an inhibitor of TMPRSS2 and related serine proteases. Employing a pathogenic animal model of SARS-CoV infection, we demonstrated that viral spread and pathogenesis of SARS-CoV is driven by serine rather than cysteine proteases and can be effectively prevented by camostat. Camostat has been clinically used to treat chronic pancreatitis, and thus represents an exciting potential therapeutic for respiratory coronavirus infections. Our results indicate that camostat, or similar serine protease inhibitors, might be an effective option for treatment of SARS and

  14. Calibration Fixture For Anemometer Probes

    Science.gov (United States)

    Lewis, Charles R.; Nagel, Robert T.

    1993-01-01

    Fixture facilitates calibration of three-dimensional sideflow thermal anemometer probes. With fixture, probe oriented at number of angles throughout its design range. Readings calibrated as function of orientation in airflow. Calibration repeatable and verifiable.

  15. Heatshield for Extreme Entry Environment Technology (HEEET)

    Science.gov (United States)

    Venkatapathy, E.; Ellerby, D.; Stackpoole, M..; Peterson, K.; Gage, P.; Beerman, A.; Blosser, M.; Chinnapongse, R.; Dillman, R.; Feldman, J.; Gasch, M.; Munk, M.; Prabhu, D.; Poteet, C.

    2013-01-01

    Heat-shield for Extreme Entry Technology (HEEET) project is based on the 3-D Woven TPS, an emerging innovative and game changing technology funded by SMD and STMD to fill the ablative TPS gap that exists currently for reaching the depths of Saturn and Venus. Woven TPS technology will address the challenges currently faced by the Venus, Saturn, and higher speed sample return mission Science community due to lack of availability of the only TPS, namely Carbon Phenolic and enable the Science community to move forward with proposals in this decade with Woven TPS. This presentation describes the approach in maturing the technology in the next three years enabling NF-4 mission proposers to address the challenges of Venus, Saturn or higher speed sample return missions.

  16. Lattice Boltzmann modeling of water entry problems

    Science.gov (United States)

    Zarghami, A.; Falcucci, G.; Jannelli, E.; Succi, S.; Porfiri, M.; Ubertini, S.

    2014-12-01

    This paper deals with the simulation of water entry problems using the lattice Boltzmann method (LBM). The dynamics of the free surface is treated through the mass and momentum fluxes across the interface cells. A bounce-back boundary condition is utilized to model the contact between the fluid and the moving object. The method is implemented for the analysis of a two-dimensional flow physics produced by a symmetric wedge entering vertically a weakly-compressible fluid at a constant velocity. The method is used to predict the wetted length, the height of water pile-up, the pressure distribution and the overall force on the wedge. The accuracy of the numerical results is demonstrated through comparisons with data reported in the literature.

  17. Probing properties of cold radiofrequency plasma with polymer probe

    Science.gov (United States)

    Bormashenko, E.; Chaniel, G.; Multanen, V.

    2015-01-01

    The probe intended for the characterization of cold plasma is introduced. The probe allows the estimation of Debye length of cold plasma. The probe is based on the pronounced modification of surface properties (wettability) of polymer films by cold plasmas. The probe was tested with the cold radiofrequency inductive air plasma discharge. The Debye length and the concentration of charge carriers were estimated for various gas pressures. The reported results coincide reasonably with the corresponding values established by other methods. The probe makes possible measurement of characteristics of cold plasmas in closed chambers.

  18. Probing Properties of Cold Radiofrequency Plasma with Polymer Probe

    CERN Document Server

    Bormashenko, Edward; Multanen, Victor

    2014-01-01

    The probe intended for the characterization of cold plasma is introduced. The probe allows estimation of the Debye length of the cold plasma. The probe is based on the pronounced modification of surface properties (wettability) of polymer films by cold plasmas. The probe was tested with the cold radiofrequency inductive air plasma discharge. The Debye length and the concentration of charge carriers were estimated for various gas pressures. The reported results coincide reasonably with the corresponding values established by other methods. The probe makes possible measurement of characteristics of cold plasmas in closed chambers.

  19. Are entry criteria for cataract surgery justified?

    Directory of Open Access Journals (Sweden)

    Daniel Böhringer

    Full Text Available PURPOSE: The German Ophthalmological Society (GOS recently proposed surgical entry criteria, i.e. 300 cataract surgeries. We herein correlate the surgical hands-on experience with the risk of posterior capsule ruptures in order to assess whether this number is appropriate. METHODS: We identified all cataract operations that had been performed at the University Eye Hospital Freiburg since 1995. For each surgeon, we assigned a running number to his/her procedures in the order they had been performed. Thereafter, we excluded all combined procedures and the second eyes. We then selected the 5475 surgical reports between November 2008 and November 2012 for detailed review. We additionally classified each surgery into low- vs. high- à priori risk for posterior capsule ruptures. We fitted a multifactorial logistic regression model to assess the GOS recommendation of 300 surgeries under supervision. In the low-risk group, we additionally visualized the 'typical' learning curve by plotting the posterior capsule ruptures against the respective rank numbers. RESULTS: The odds ratio for posterior capsule ruptures of 'learning-mode' (one of the respective surgeon's 300 first procedures vs. the non-learning-mode was 3.8 (p<0.0001. By contrast, classification into the low-risk group lowered the risk of posterior capsule ruptures three fold (p<0.0001. According to the low-risk plot, the surgeons started with a complication rate of 4% and continuously improved towards 0.5% after 1500 operations. Thereafter, the rate increased again and stabilized around one percent. CONCLUSION: The learning curve with respect to posterior capsule ruptures is surprisingly flat. The GOS entry criterion of 300 cataract procedures is therefore most likely justified. Careful selection of low-risk patients for the training surgeons may help in reducing the rate of posterior capsule ruptures during training.

  20. Coupling approaches used in atmospheric entry models

    Science.gov (United States)

    Gritsevich, M. I.

    2012-09-01

    While a planet orbits the Sun, it is subject to impact by smaller objects, ranging from tiny dust particles and space debris to much larger asteroids and comets. Such collisions have taken place frequently over geological time and played an important role in the evolution of planets and the development of life on the Earth. Though the search for near-Earth objects addresses one of the main points of the Asteroid and Comet Hazard, one should not underestimate the useful information to be gleaned from smaller atmospheric encounters, known as meteors or fireballs. Not only do these events help determine the linkages between meteorites and their parent bodies; due to their relative regularity they provide a good statistical basis for analysis. For successful cases with found meteorites, the detailed atmospheric path record is an excellent tool to test and improve existing entry models assuring the robustness of their implementation. There are many more important scientific questions meteoroids help us to answer, among them: Where do these objects come from, what are their origins, physical properties and chemical composition? What are the shapes and bulk densities of the space objects which fully ablate in an atmosphere and do not reach the planetary surface? Which values are directly measured and which are initially assumed as input to various models? How to couple both fragmentation and ablation effects in the model, taking real size distribution of fragments into account? How to specify and speed up the recovery of a recently fallen meteorites, not letting weathering to affect samples too much? How big is the pre-atmospheric projectile to terminal body ratio in terms of their mass/volume? Which exact parameters beside initial mass define this ratio? More generally, how entering object affects Earth's atmosphere and (if applicable) Earth's surface? How to predict these impact consequences based on atmospheric trajectory data? How to describe atmospheric entry

  1. Passive Earth Entry Vehicle Landing Test

    Science.gov (United States)

    Kellas, Sotiris

    2017-01-01

    Two full-scale passive Earth Entry Vehicles (EEV) with realistic structure, surrogate sample container, and surrogate Thermal Protection System (TPS) were built at NASA Langley Research Center (LaRC) and tested at the Utah Test and Training Range (UTTR). The main test objective was to demonstrate structural integrity and investigate possible impact response deviations of the realistic vehicle as compared to rigid penetrometer responses. With the exception of the surrogate TPS and minor structural differences in the back shell construction, the two test vehicles were identical in geometry and both utilized the Integrated Composite Stiffener Structure (ICoSS) structural concept in the forward shell. The ICoSS concept is a lightweight and highly adaptable composite concept developed at NASA LaRC specifically for entry vehicle TPS carrier structures. The instrumented test vehicles were released from a helicopter approximately 400 m above ground. The drop height was selected such that at least 98% of the vehicles terminal velocity would be achieved. While drop tests of spherical penetrometers and a low fidelity aerodynamic EEV model were conducted at UTTR in 1998 and 2000, this was the first time a passive EEV with flight-like structure, surrogate TPS, and sample container was tested at UTTR for the purpose of complete structural system validation. Test results showed that at a landing vertical speed of approximately 30 m/s, the test vehicle maintained structural integrity and enough rigidity to penetrate the sandy clay surface thus attenuating the landing load, as measured at the vehicle CG, to less than 600 g. This measured deceleration was found to be in family with rigid penetrometer test data from the 1998 and 2000 test campaigns. Design implications of vehicle structure/soil interaction with respect to sample container and sample survivability are briefly discussed.

  2. Phoenix Conductivity Probe

    Science.gov (United States)

    2008-01-01

    This image taken by the Surface Stereo Imager on Sol 49, or the 49th Martian day of the mission (July 14, 2008), shows thermal and electrical conductivity probe on NASA's Phoenix Mars Lander's Robotic Arm. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is led by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  3. Atom probe tomography today

    OpenAIRE

    Alfred Cerezo; Peter H. Clifton; Mark J. Galtrey; Humphreys, Colin J.; Kelly, Thomas. F.; David J. Larson; Sergio Lozano-Perez; Marquis, Emmanuelle A.; Oliver, Rachel A.; Gang Sha; Keith Thompson; Mathijs Zandbergen; Roger L. Alvis

    2007-01-01

    This review aims to describe and illustrate the advances in the application of atom probe tomography that have been made possible by recent developments, particularly in specimen preparation techniques (using dual-beam focused-ion beam instruments) but also of the more routine use of laser pulsing. The combination of these two developments now permits atomic-scale investigation of site-specific regions within engineering alloys (e.g. at grain boundaries and in the vicinity of cracks) and also...

  4. Einstein Inflationary Probe (EIP)

    Science.gov (United States)

    Hinshaw, Gary

    2004-01-01

    I will discuss plans to develop a concept for the Einstein Inflation Probe: a mission to detect gravity waves from inflation via the unique signature they impart to the cosmic microwave background (CMB) polarization. A sensitive CMB polarization satellite may be the only way to probe physics at the grand-unified theory (GUT) scale, exceeding by 12 orders of magnitude the energies studied at the Large Hadron Collider. A detection of gravity waves would represent a remarkable confirmation of the inflationary paradigm and set the energy scale at which inflation occurred when the universe was a fraction of a second old. Even a strong upper limit to the gravity wave amplitude would be significant, ruling out many common models of inflation, and pointing to inflation occurring at much lower energy, if at all. Measuring gravity waves via the CMB polarization will be challenging. We will undertake a comprehensive study to identify the critical scientific requirements for the mission and their derived instrumental performance requirements. At the core of the study will be an assessment of what is scientifically and experimentally optimal within the scope and purpose of the Einstein Inflation Probe.

  5. Nanoscale thermal probing

    Directory of Open Access Journals (Sweden)

    Yanan Yue

    2012-03-01

    Full Text Available Nanoscale novel devices have raised the demand for nanoscale thermal characterization that is critical for evaluating the device performance and durability. Achieving nanoscale spatial resolution and high accuracy in temperature measurement is very challenging due to the limitation of measurement pathways. In this review, we discuss four methodologies currently developed in nanoscale surface imaging and temperature measurement. To overcome the restriction of the conventional methods, the scanning thermal microscopy technique is widely used. From the perspective of measuring target, the optical feature size method can be applied by using either Raman or fluorescence thermometry. The near-field optical method that measures nanoscale temperature by focusing the optical field to a nano-sized region provides a non-contact and non-destructive way for nanoscale thermal probing. Although the resistance thermometry based on nano-sized thermal sensors is possible for nanoscale thermal probing, significant effort is still needed to reduce the size of the current sensors by using advanced fabrication techniques. At the same time, the development of nanoscale imaging techniques, such as fluorescence imaging, provides a great potential solution to resolve the nanoscale thermal probing problem.

  6. Nine New Fluorescent Probes

    Science.gov (United States)

    Lin, Tsung-I.; Jovanovic, Misa V.; Dowben, Robert M.

    1989-06-01

    Absorption and fluorescence spectroscopic studies are reported here for nine new fluorescent probes recently synthesized in our laboratories: four pyrene derivatives with substituents of (i) 1,3-diacetoxy-6,8-dichlorosulfonyl, (ii) 1,3-dihydroxy-6,8-disodiumsulfonate, (iii) 1,3-disodiumsulfonate, and (iv) l-ethoxy-3,6,8-trisodiumsulfonate groups, and five [7-julolidino] coumarin derivatives with substituents of (v) 3-carboxylate-4-methyl, (vi) 3- methylcarboxylate, (vii) 3-acetate-4-methyl, (viii) 3-propionate-4-methyl, and (ix) 3-sulfonate-4-methyl groups. Pyrene compounds i and ii and coumarin compounds v and vi exhibit interesting absorbance and fluorescence properties: their absorption maxima are red shifted compared to the parent compound to the blue-green region, and the band width broadens considerably. All four blue-absorbing dyes fluoresce intensely in the green region, and the two pyrene compounds emit at such long wavelengths without formation of excimers. The fluorescence properties of these compounds are quite environment-sensitive: considerable spectral shifts and fluorescence intensity changes have been observed in the pH range from 3 to 10 and in a wide variety of polar and hydrophobic solvents with vastly different dielectric constants. The high extinction and fluorescence quantum yield of these probes make them ideal fluorescent labeling reagents for proteins, antibodies, nucleic acids, and cellular organelles. The pH and hydrophobicity-dependent fluorescence changes can be utilized as optical pH and/or hydrophobicity indicators for mapping environmental difference in various cellular components in a single cell. Since all nine probes absorb in the UV, but emit at different wavelengths in the visible, these two groups of compounds offer an advantage of utilizing a single monochromatic light source (e.g., a nitrogen laser) to achieve multi-wavelength detection for flow cytometry application. As a first step to explore potential application in

  7. Entry, Descent, and Landing Operations Analysis for the Stardust Entry Capsule

    Science.gov (United States)

    Desai, Prasun N.; Lyons, Dan T.; Tooley, Jeff; Kangas, Julie

    2008-01-01

    On the morning of January 15, 2006, the Stardust capsule successfully landed at the Utah Test and Training range in northwest Utah returning cometary samples from the comet Wild-2. An overview of the entry, descent, and landing (EDL) trajectory analysis that was performed for targeting during the mission operations phase upon final approach to Earth is described. The final orbit determination solution produced an inertial entry flight-path angle of -8.21 deg (the desired nominal value) with a 3-sigma uncertainty of +/-0.0017 deg (2% of the requirement). The navigation and EDL operations effort accurately delivered the entry capsule to the desired landing site. The final landing location was 8.1 km from the target, which was well within the allowable landing area. Overall, the Earth approach operation procedures worked well and there were no issues (logistically or performance based) that arose. As a result, the process of targeting a capsule from an interplanetary trajectory and accurately landing it on Earth was successfully demonstrated.

  8. 19 CFR 145.24 - Amendment of entry.

    Science.gov (United States)

    2010-04-01

    ... director is satisfied that the objection is valid and timely, he shall amend the mail entry. If the duty... 19 Customs Duties 2 2010-04-01 2010-04-01 false Amendment of entry. 145.24 Section 145.24 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE...

  9. 19 CFR 4.35 - Unlading outside port of entry.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Unlading outside port of entry. 4.35 Section 4.35 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE... of entry. (a) Upon written application from the interested party, the port director concerned, if...

  10. Strategic advantage and the optimal exercise of entry options

    NARCIS (Netherlands)

    E.C. Perotti; S. Rossetto

    2001-01-01

    We investigate the timing and the valuation of strategic investment aimed at enhancing entry opportunities in related market segments. As demand is uncertain, entry options should be exercised at the optimal time, trading off the market share gain against the option to wait until more information is

  11. The Importance of Prior Probabilities for Entry Page Search

    NARCIS (Netherlands)

    Kraaij, W.; Westerveld, T.H.W.; Hiemstra, D.

    2002-01-01

    An important class of searches on the world-wide-web has the goal to find an entry page (homepage) of an organisation. Entry page search is quite different from Ad Hoc search. Indeed a plain Ad Hoc system performs disappointingly. We explored three non-content features of web pages: page length, num

  12. 18 CFR 33.5 - Proposed accounting entries.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Proposed accounting... § 33.5 Proposed accounting entries. If the applicant is required to maintain its books of account in... present proposed accounting entries showing the effect of the transaction with sufficient detail...

  13. 15 CFR 2011.204 - Entry of specialty sugars.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Entry of specialty sugars. 2011.204... UNITED STATES TRADE REPRESENTATIVE ALLOCATION OF TARIFF-RATE QUOTA ON IMPORTED SUGARS, SYRUPS AND MOLASSES Specialty Sugar § 2011.204 Entry of specialty sugars. An importer or the importer's agent...

  14. Strategic advantage and the optimal exercise of entry options

    NARCIS (Netherlands)

    Perotti, E.C.; Rossetto, S.

    2001-01-01

    We investigate the timing and the valuation of strategic investment aimed at enhancing entry opportunities in related market segments. As demand is uncertain, entry options should be exercised at the optimal time, trading off the market share gain against the option to wait until more information is

  15. Racial/Ethnic Disparities in ADHD Diagnosis by Kindergarten Entry

    Science.gov (United States)

    Morgan, Paul L.; Hillemeier, Marianne M.; Farkas, George; Maczuga, Steve

    2014-01-01

    Background: Whether and to what extent racial/ethnic disparities in attention-deficit/hyperactivity disorder (ADHD) diagnosis occur by kindergarten entry is currently unknown. We investigated risk factors associated with an ADHD diagnosis by kindergarten entry generally, and specifically whether racial/ethnic disparities in ADHD diagnosis occur by…

  16. Foreign Bank Entry and Credit Allocation in Emerging Markets

    NARCIS (Netherlands)

    Degryse, H.A.; Havrylchyk, O.; Jurzyk, E.; Kozak, S.

    2009-01-01

    We employ a unique data set containing bank-specific information to explore how foreign bank entry determines credit allocation in emerging markets. We investigate the impact of the mode of foreign entry (greenfield or takeover) on banks’ portfolio allocation to borrowers with different degrees of

  17. Foreign Bank Entry and Credit Allocation in Emerging Markets

    NARCIS (Netherlands)

    Degryse, H.A.; Havrylchyk, O.; Jurzyk, E.; Kozak, S.

    2009-01-01

    We employ a unique data set containing bank-specific information to explore how foreign bank entry determines credit allocation in emerging markets. We investigate the impact of the mode of foreign entry (greenfield or takeover) on banks’ portfolio allocation to borrowers with different degrees of i

  18. Racial/Ethnic Disparities in ADHD Diagnosis by Kindergarten Entry

    Science.gov (United States)

    Morgan, Paul L.; Hillemeier, Marianne M.; Farkas, George; Maczuga, Steve

    2014-01-01

    Background: Whether and to what extent racial/ethnic disparities in attention-deficit/hyperactivity disorder (ADHD) diagnosis occur by kindergarten entry is currently unknown. We investigated risk factors associated with an ADHD diagnosis by kindergarten entry generally, and specifically whether racial/ethnic disparities in ADHD diagnosis occur by…

  19. 19 CFR 146.64 - Entry for warehouse.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Entry for warehouse. 146.64 Section 146.64 Customs... (CONTINUED) FOREIGN TRADE ZONES Transfer of Merchandise From a Zone § 146.64 Entry for warehouse. (a) Foreign... status may not be entered for warehouse from a zone. Merchandise in nonprivileged foreign...

  20. 19 CFR 151.63 - Information on entry summary.

    Science.gov (United States)

    2010-04-01

    ... estimated or actual net weight of the wool or hair in its condition as imported, its total estimated clean... THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.63 Information on entry summary. Each entry summary covering wool or hair subject to duty at a rate per...

  1. 31 CFR 357.0 - Book-entry systems.

    Science.gov (United States)

    2010-07-01

    ... non-Internet-based book-entry system maintained by Treasury for purchasing and holding marketable...) TreasuryDirect ®. TreasuryDirect is a book-entry, online system maintained by the Department of the Treasury for purchasing and holding eligible marketable Treasury securities, United States Savings...

  2. 19 CFR 146.63 - Entry for consumption.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Entry for consumption. 146.63 Section 146.63... TREASURY (CONTINUED) FOREIGN TRADE ZONES Transfer of Merchandise From a Zone § 146.63 Entry for consumption... status may be entered for consumption from a zone. (b) Zone-restricted merchandise. Merchandise in a zone...

  3. Development of Mackintosh Probe Extractor

    Science.gov (United States)

    Rahman, Noor Khazanah A.; Kaamin, Masiri; Suwandi, Amir Khan; Sahat, Suhaila; Jahaya Kesot, Mohd

    2016-11-01

    Dynamic probing is a continuous soil investigation technique, which is one of the simplest soil penetration test. It basically consist of repeatedly driving a metal tipped probe into the ground using a drop weight of fixed mass and travel. Testing was carried out continuously from ground level to the final penetration depth. Once the soil investigation work done, it is difficult to pull out the probe rod from the ground, due to strong soil structure grip against probe cone and prevent the probe rod out from the ground. Thus, in this case, a tool named Extracting Probe was created to assist in the process of retracting the probe rod from the ground. In addition, Extracting Probe also can reduce the time to extract the probe rod from the ground compare with the conventional method. At the same time, it also can reduce manpower cost because only one worker involve to handle this tool compare with conventional method used two or more workers. From experiment that have been done we found that the time difference between conventional tools and extracting probe is significant, average time difference is 155 minutes. In addition the extracting probe can reduce manpower usage, and also labour cost for operating the tool. With all these advantages makes this tool has the potential to be marketed.

  4. Probe-based data storage

    CERN Document Server

    Koelmans, Wabe W; Abelmann, L

    2015-01-01

    Probe-based data storage attracted many researchers from academia and industry, resulting in unprecendeted high data-density demonstrations. This topical review gives a comprehensive overview of the main contributions that led to the major accomplishments in probe-based data storage. The most investigated technologies are reviewed: topographic, phase-change, magnetic, ferroelectric and atomic and molecular storage. Also, the positioning of probes and recording media, the cantilever arrays and parallel readout of the arrays of cantilevers are discussed. This overview serves two purposes. First, it provides an overview for new researchers entering the field of probe storage, as probe storage seems to be the only way to achieve data storage at atomic densities. Secondly, there is an enormous wealth of invaluable findings that can also be applied to many other fields of nanoscale research such as probe-based nanolithography, 3D nanopatterning, solid-state memory technologies and ultrafast probe microscopy.

  5. Extended High-Gain Observer for Mars Entry Guidance

    Directory of Open Access Journals (Sweden)

    Pingyuan Cui

    2013-02-01

    Full Text Available To deliver a Mars entry vehicle to the prescribed parachute deployment point, active entry guidance is essential. This paper addresses the problem of Mars atmospheric entry guidance through drag tracking method with extended high gain observer. First, an extended high gain observer combined with feedback linearization is applied in drag tracking for Mars entry longitudinal guidance.  The observer estimates the drag and drag rate for drag tracking, estimates the perturbation due to model uncertainty and disturbance, and compensate for the perturbation by canceling its estimate. Then, bank reversal is adopted in the lateral plane to reduce the cross-range error. Finally, Mars entry simulation is performed to assess the performance of the adaptive guidance law. The results demonstrate that the proposed guidance law exhibits good performance.

  6. Strategic Orientation and Order of Market Entry of Food Firms

    Directory of Open Access Journals (Sweden)

    rasoul ghollamzadeh

    2011-12-01

    One of the strategic launch decisions is the order of market entry. Adoption of a suitable competitive strategy is dependent on firm's decision on market entry earlier or later than competitors. This research aims to analyze the relationship between order of market entry and firms’ strategic orientation. For this purpose, three strategies have been defined as cost leadership strategy, innovation differentiation strategy and marketing differentiation strategy. In this study, the essential question is whether firms use a different strategy based on their order of market entry? The proposed model has been examined on a sample of 102 manufacturing companies in the food industry using Structural Equation Modeling based on the methodology of Partial Least Squares (PLS. Findings indicate a direct influence of order of market entry on adopting a particular strategy by the firms, so that pioneer companies tend more to use differentiation strategy at two levels of marketing and innovation, while cost leadership is more common among followers.

  7. Strategic Orientation and Order of Market Entry of Food Firms

    Directory of Open Access Journals (Sweden)

    Rasoul Ghollamzadeh

    2011-01-01

    Full Text Available One of the strategic launch decisions is the order of market entry. Adoption of a suitable competitive strategy is dependent on firm's decision on market entry earlier or later than competitors. This research aims to analyze the relationship between order of market entry and firms’ strategic orientation. For this purpose, three strategies have been defined as cost leadership strategy, innovation differentiation strategy and marketing differentiation strategy. In this study, the essential question is whether firms use a different strategy based on their order of market entry? The proposed model has been examined on a sample of 102 manufacturing companies in the food industry using Structural Equation Modeling based on the methodology of Partial Least Squares (PLS. Findings indicate a direct influence of order of market entry on adopting a particular strategy by the firms, so that pioneer companies tend more to use differentiation strategy at two levels of marketing and innovation, while cost leadership is more common among followers.

  8. Market entry decisions: effects of absolute and relative confidence.

    Science.gov (United States)

    Bolger, Fergus; Pulford, Briony D; Colman, Andrew M

    2008-01-01

    In a market entry game, the number of entrants usually approaches game-theoretic equilibrium quickly, but in real-world markets business start-ups typically exceed market capacity, resulting in chronically high failure rates and suboptimal industry profits. Excessive entry has been attributed to overconfidence arising when expected payoffs depend partly on skill. In an experimental test of this hypothesis, 96 participants played 24 rounds of a market entry game, with expected payoffs dependent partly on skill on half the rounds, after their confidence was manipulated and measured. The results provide direct support for the hypothesis that high levels of confidence are largely responsible for excessive entry, and they suggest that absolute confidence, independent of interpersonal comparison, rather than confidence about one's abilities relative to others, drives excessive entry decisions when skill is involved.

  9. PROcess Based Diagnostics PROBE

    Science.gov (United States)

    Clune, T.; Schmidt, G.; Kuo, K.; Bauer, M.; Oloso, H.

    2013-01-01

    Many of the aspects of the climate system that are of the greatest interest (e.g., the sensitivity of the system to external forcings) are emergent properties that arise via the complex interplay between disparate processes. This is also true for climate models most diagnostics are not a function of an isolated portion of source code, but rather are affected by multiple components and procedures. Thus any model-observation mismatch is hard to attribute to any specific piece of code or imperfection in a specific model assumption. An alternative approach is to identify diagnostics that are more closely tied to specific processes -- implying that if a mismatch is found, it should be much easier to identify and address specific algorithmic choices that will improve the simulation. However, this approach requires looking at model output and observational data in a more sophisticated way than the more traditional production of monthly or annual mean quantities. The data must instead be filtered in time and space for examples of the specific process being targeted.We are developing a data analysis environment called PROcess-Based Explorer (PROBE) that seeks to enable efficient and systematic computation of process-based diagnostics on very large sets of data. In this environment, investigators can define arbitrarily complex filters and then seamlessly perform computations in parallel on the filtered output from their model. The same analysis can be performed on additional related data sets (e.g., reanalyses) thereby enabling routine comparisons between model and observational data. PROBE also incorporates workflow technology to automatically update computed diagnostics for subsequent executions of a model. In this presentation, we will discuss the design and current status of PROBE as well as share results from some preliminary use cases.

  10. Entry and exit facet laser damage of optical windows with random antireflective surface structures

    Science.gov (United States)

    Sapkota, Gopal; Case, Jason R.; Potter, Matthew G.; Busse, Lynda E.; Shaw, L. Brandon; Sanghera, Jasbinder S.; Aggarwal, Ishwar D.; Poutous, Menelaos K.

    2016-12-01

    Nanosecond duration, high intensity and high average power laser pulses induce damage on uncoated optics, due to localized field enhancement at the exit surface of the components. Anti-reflection (AR) coated optics, due to their (multiple) thin film boundaries, have similar field enhancement regions, which lead to laser damage on both entry and exit sides. Nano-scale structured optical interfaces with AR performance (ARSS) have been widely demonstrated, and found to have higher laser damage resistance than conventional AR coatings. Comprehensive tests of optical entry and exit structured-surface laser damage using nanosecond pulses for ARSS are not widely available. We measured the laser damage of random anti-reflective surface structures (rARSS), on planar, optical quality, fused silica substrates, using single 6-8ns duration pulses at 1064 nm wavelength. The single-sided rARSS substrates were optimized for Fresnel reflectance suppression at 1064 nm, and the measured transmittance at normal incidence was increased by 3.2%, with a possible theoretical maximum of 3.5%. The high energy laser beam was focused to increase the incident intensity, in order to probe values above and below the damage thresholds reported in the literature. The source laser Q-switch durations were used to directly control incident fluence. Multiple locations were tested for each Q-switch setting, to build a statistical relationship between the fluence and damaging events. Single-sided, AR random surface structured substrates were tested, using entry and exit side orientations, to determine any effects the random structures may have in the damage induced by the field enhancement on the exit side. We found that the AR randomly structured surfaces have a higher resistance, to the onset of laser damage, when they are located at the entry (structured) side of the substrates. In comparison, when the same AR random structures are in the beam exit side of the substrates, the onset of laser damage

  11. Atom probe tomography today

    Directory of Open Access Journals (Sweden)

    Alfred Cerezo

    2007-12-01

    Full Text Available This review aims to describe and illustrate the advances in the application of atom probe tomography that have been made possible by recent developments, particularly in specimen preparation techniques (using dual-beam focused-ion beam instruments but also of the more routine use of laser pulsing. The combination of these two developments now permits atomic-scale investigation of site-specific regions within engineering alloys (e.g. at grain boundaries and in the vicinity of cracks and also the atomic-level characterization of interfaces in multilayers, oxide films, and semiconductor materials and devices.

  12. Experimental probes of axions

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Aaron S.; /Fermilab

    2009-10-01

    Experimental searches for axions or axion-like particles rely on semiclassical phenomena resulting from the postulated coupling of the axion to two photons. Sensitive probes of the extremely small coupling constant can be made by exploiting familiar, coherent electromagnetic laboratory techniques, including resonant enhancement of transitions using microwave and optical cavities, Bragg scattering, and coherent photon-axion oscillations. The axion beam may either be astrophysical in origin as in the case of dark matter axion searches and solar axion searches, or created in the laboratory from laser interactions with magnetic fields. This note is meant to be a sampling of recent experimental results.

  13. Atom Probe Tomography 2012

    Science.gov (United States)

    Kelly, Thomas F.; Larson, David J.

    2012-08-01

    In the world of tomographic imaging, atom probe tomography (APT) occupies the high-spatial-resolution end of the spectrum. It is highly complementary to electron tomography and is applicable to a wide range of materials. The current state of APT is reviewed. Emphasis is placed on applications and data analysis as they apply to many fields of research and development including metals, semiconductors, ceramics, and organic materials. We also provide a brief review of the history and the instrumentation associated with APT and an assessment of the existing challenges in the field.

  14. Mobile Probing Kit

    DEFF Research Database (Denmark)

    Larsen, Jakob Eg; Sørensen, Lene Tolstrup; Sørensen, J.K.

    2007-01-01

    characterized as being highly nomadic and thus potential users of mobile and ubiquitous technologies. The methodology has been applied in the 1ST MAGNET Beyond project in order to obtain user needs and requirements in the process of developing pilot services. We report on the initial findings from applying......Mobile Probing Kit is a low tech and low cost methodology for obtaining inspiration and insights into user needs, requirements and ideas in the early phases of a system's development process. The methodology is developed to identify user needs, requirements and ideas among knowledge workers...

  15. 9 CFR 381.208 - Poultry products offered for entry and entered to be handled and transported as domestic; entry...

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Poultry products offered for entry and entered to be handled and transported as domestic; entry into official establishments; transportation. 381.208 Section 381.208 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY ORGANIZATION AND...

  16. Firm entry and aggregate efficiency growth: An optimal dynamic - Program of entry and R&D investment

    Directory of Open Access Journals (Sweden)

    Asma Raies

    2013-12-01

    Full Text Available The effect of entry on the aggregate efficiency growth is still theoretically and empirically unresolved. Many studies focused on this effect in short and long-run, without considering the dynamic transition and how do entry affect the convergence of the industrytoward its long-run equilibrium? This paper aims to provide an answer and to fill this gap by employingoptimal control principles. Our model exhibits saddlepath stability and shows that the effect of entry and entry liberalizing policy (reducing the entry cost on the aggregate efficiency growth may be positive, negative or nil depending on the industry’s initial characteristics (size and R&D. This theoretical result can justify the inconclusive current empirical evidence.

  17. Swiss Army Pathogen: The Salmonella Entry Toolkit

    Directory of Open Access Journals (Sweden)

    Peter J. Hume

    2017-08-01

    Full Text Available Salmonella causes disease in humans and animals ranging from mild self-limiting gastroenteritis to potentially life-threatening typhoid fever. Salmonellosis remains a considerable cause of morbidity and mortality globally, and hence imposes a huge socio-economic burden worldwide. A key property of all pathogenic Salmonella strains is the ability to invade non-phagocytic host cells. The major determinant of this invasiveness is a Type 3 Secretion System (T3SS, a molecular syringe that injects virulence effector proteins directly into target host cells. These effectors cooperatively manipulate multiple host cell signaling pathways to drive pathogen internalization. Salmonella does not only rely on these injected effectors, but also uses several other T3SS-independent mechanisms to gain entry into host cells. This review summarizes our current understanding of the methods used by Salmonella for cell invasion, with a focus on the host signaling networks that must be coordinately exploited for the pathogen to achieve its goal.

  18. On Heatshield Shapes for Mars Entry Capsules

    Science.gov (United States)

    Prabhu, DInesh K.; Saunders, David A.

    2012-01-01

    The 70deg sphere-cone - the standard geometry for all US Mars entry missions - is thoroughly examined via flow field simulations at a select few peak heating points along candidate flight trajectories. Emphasis is placed on turbulent heating based on the Baldwin- Lomax turbulence model. It is shown that increased leeward turbulent heating for a 70 sphere-cone flying at angle of attack is primarily due to the discontinuity in curvature between the spherical nose cap and the conical frustum - the attachment of the sonic line at this sphere-cone junction leads to a supersonic edge Mach number over the leeward acreage. In an attempt to mitigate this problem of elevated turbulent heating, alternate geometries, without any curvature discontinuities in the acreage, are developed. Two approaches, one based on nonlinear optimization with constraints, and one based on the use of non-uniform rational B-splines, are considered. All configurations examined remain axisymmetric. The aerothermal performance of alternate geometries is shown to be superior to that of the 70 sphere-cone.

  19. Inflatable Emergency Atmospheric-Entry Vehicles

    Science.gov (United States)

    Jones, Jack; Hall, Jeffrey; Wu, Jiunn Jeng

    2004-01-01

    In response to the loss of seven astronauts in the Space Shuttle Columbia disaster, large, lightweight, inflatable atmospheric- entry vehicles have been proposed as means of emergency descent and landing for persons who must abandon a spacecraft that is about to reenter the atmosphere and has been determined to be unable to land safely. Such a vehicle would act as an atmospheric decelerator at supersonic speed in the upper atmosphere, and a smaller, central astronaut pod could then separate at lower altitudes and parachute separately to Earth. Astronaut-rescue systems that have been considered previously have been massive, and the cost of designing them has exceeded the cost of fabrication of a space shuttle. In contrast, an inflatable emergency-landing vehicle according to the proposal would have a mass between 100 and 200 kg, could be stored in a volume of approximately 0.2 to 0.4 cu m, and could likely be designed and built much less expensively. When fully inflated, the escape vehicle behaves as a large balloon parachute, or ballute. Due to very low mass-per-surface area, a large radius, and a large coefficient of drag, ballutes decelerate at much higher altitudes and with much lower heating rates than the space shuttle. Although the space shuttle atmospheric reentry results in surface temperatures of about 1,600 C, ballutes can be designed for maximum temperatures below 600 C. This allows ballutes to be fabricated with lightweight ZYLON(Registered TradeMark) or polybenzoxazole (PBO), or equivalent.

  20. Intracellular route of canine parvovirus entry.

    Science.gov (United States)

    Vihinen-Ranta, M; Kalela, A; Mäkinen, P; Kakkola, L; Marjomäki, V; Vuento, M

    1998-01-01

    The present study was designed to investigate the endocytic pathway involved in canine parvovirus (CPV) infection. Reduced temperature (18 degrees C) or the microtubule-depolymerizing drug nocodazole was found to inhibit productive infection of canine A72 cells by CPV and caused CPV to be retained in cytoplasmic vesicles as indicated by immunofluorescence microscopy. Consistent with previously published results, these data indicate that CPV enters a host cell via an endocytic route and further suggest that microtubule-dependent delivery of CPV to late endosomes is required for productive infection. Cytoplasmic microinjection of CPV particles was used to circumvent the endocytosis and membrane fusion steps in the entry process. Microinjection experiments showed that CPV particles which were injected directly into the cytoplasm, thus avoiding the endocytic pathway, were unable to initiate progeny virus production. CPV treated at pH 5.0 prior to microinjection was unable to initiate virus production, showing that factors of the endocytic route other than low pH are necessary for the initiation of infection by CPV.

  1. HTCC: Broad Range Inhibitor of Coronavirus Entry.

    Directory of Open Access Journals (Sweden)

    Aleksandra Milewska

    Full Text Available To date, six human coronaviruses have been known, all of which are associated with respiratory infections in humans. With the exception of the highly pathogenic SARS and MERS coronaviruses, human coronaviruses (HCoV-NL63, HCoV-OC43, HCoV-229E, and HCoV-HKU1 circulate worldwide and typically cause the common cold. In most cases, infection with these viruses does not lead to severe disease, although acute infections in infants, the elderly, and immunocompromised patients may progress to severe disease requiring hospitalization. Importantly, no drugs against human coronaviruses exist, and only supportive therapy is available. Previously, we proposed the cationically modified chitosan, N-(2-hydroxypropyl-3-trimethylammonium chitosan chloride (HTCC, and its hydrophobically-modified derivative (HM-HTCC as potent inhibitors of the coronavirus HCoV-NL63. Here, we show that HTCC inhibits interaction of a virus with its receptor and thus blocks the entry. Further, we demonstrate that HTCC polymers with different degrees of substitution act as effective inhibitors of all low-pathogenic human coronaviruses.

  2. Lysosomotropic agents as HCV entry inhibitors

    Directory of Open Access Journals (Sweden)

    Nawaz Zafar

    2011-04-01

    Full Text Available Abstract HCV has two envelop proteins named as E1 and E2 which play an important role in cell entry through two main pathways: direct fusion at the plasma membrane and receptor-mediated endocytosis. Fusion of the HCV envelope proteins is triggered by low pH within the endosome. Lysosomotropic agents (LA such as Chloroquine and Ammonium chloride (NH4Cl are the weak bases and penetrate in lysosome as protonated form and increase the intracellular pH. To investigate the antiviral effect of LA (Chloroquine and NH4Cl on pH dependent endocytosis, HCV pseudoparticles (HCVpp of 1a and 3a genotype were produced and used to infect liver cells. The toxicological effects of Chloroquine and NH4Cl were tested in liver cells through MTT cell proliferation assay. For antiviral screening of Chloroquine and NH4Cl, liver cells were infected with HCVpp of 3a and 1a genotype in the presence or absence of different concentrations of Chloroquine and NH4Cl and there luciferase activity was determined by using a luminometer. The results demonstrated that Chloroquine and NH4Cl showed more than 50% reduction of virus infectivity at 50 μM and 10 mM concentrations respectively. These results suggest that inhibition of HCV at fusion step by increasing the lysosomal pH will be better option to treat chronic HCV.

  3. Three-dimensional acceleration planning for atmospheric entry

    Science.gov (United States)

    Chen, David Teh-Han

    The next generation of reusable launch vehicles will benefit from an improved entry guidance algorithm. Improvements have been made to the current Space Shuttle entry guidance algorithm that will provide an ability to handle aborts, reach large crossranges, and provide complete onboard planning capability. Building on the entry guidance algorithm for the Space Shuttle, three versions of a three-dimensional acceleration based entry guidance algorithm have been created and tested. The Space Shuttle entry guidance algorithm is extended to three dimensions by planning the drag profile and the occurrence of bank reversals. The three versions of the planning algorithm that have been developed are a single bank reversal planner, a two bank reversal planner, and a single bank reversal update planner. Tests of the single and two bank reversal versions show that the planning algorithms are capable of producing feasible trajectories for a wide range of various entry conditions. Integration and testing of the update planning algorithm with a feedback linearizing control law in a high fidelity simulation developed by NASA Marshall has demonstrated the algorithm's ability to handle a variety of entry conditions in an onboard environment.

  4. A Further Look at X-33 Entry Guidance and Beyond

    Science.gov (United States)

    Lu, Ping

    1999-01-01

    An entry guidance design developed at Iowa State University (ISU) for the X-33 advanced technology demonstrator is outlined and compared with the X-33 entry guidance algorithms developed at NASA Marshall. Both designs are based on the Space Shuttle entry guidance concept, but significant improvements have been made to enhance the performance and reduce the complexity. The ISU design was incorporated into MAVERIC, a high fidelity vehicle simulation software for the X-33, and evaluated in Monte Carlo simulations against random dispersions in propulsion system, wind and atmospheric properties, aerodynamic coefficients, interaction between propulsion and aerodynamics, and navigation data. The simulations clearly demonstrated the capability and precision of the ISU entry guidance design in successfully guiding the X-33 in some rather difficult flight scenarios. As the entry guidance development for the X-33 is completing, this report also offers some review of the strength and limitations of the current Shuttle-based entry guidance framework, and finally some potential candidates for next generation of more capable and cost-effective entry guidance designs are discussed.

  5. The effects of foreign banks entry in emerging market economies

    Directory of Open Access Journals (Sweden)

    MSc. Florida Veljanoska

    2011-12-01

    Full Text Available This paper investigates the effects of foreign bank entry in emerging markets. We developed a picture of a multinational bank in an emerging markets by combining statistics from several sources, in order to explore broad range of effects that brings foreign bank entry in the developing countries. Some impacts of foreign bank entry have been thoroughly studied, while others are hardly mention. Entry of foreign bank brings large benefits to host country’s financial system and economies at large. This paper is studying those benefits very carefully, by analyzing the impact of foreign bank entry on economy, government, monetary policy, large enterprises, small and medium size enterprises, domestic bank etc. But, we also consider the fact that at the same time, foreign investment in the financial sector, rises some concerns, and therefore we analyze the negative effects as well. At the end we must admit that although there are some negative consequences from foreign bank entry in emerging markets, the benefits that arise from foreign banks penetration are much more, and this trend of foreign bank entry has brought new positive economic impulse in developing world.

  6. Doppler radiation sensing of Shuttle angle of attack and TAS during entry

    Science.gov (United States)

    Foale, C. M.

    Space Shuttle true airspeed, angle of attack, and sideslip angle are currently derived from inertial guidance information. A new method is proposed which offers a potential improvement in Shuttle safety during entry. Angle of attack, sideslip angle and true airspeed could be measured directly at heights from 120 km down to 20 km by Doppler sensing three independent true airspeeds along the Shuttle body axes. Two types of Doppler measurement sensors, employing either passive detection of atmospheric radiation or coherent detection of scattered laser light are discussed. The proposed technique is essentially solid-state and robust, and is well suited for use in future small hypersonic vehicles that require flight control in the Upper Atmosphere of the earth or in probes destined for the other planets.

  7. Palladium-Copper Catalyzed Alkyne Activation as an Entry to Multicomponent Syntheses of Heterocycles

    Science.gov (United States)

    Müller, Thomas J. J.

    Alkynones and chalcones are of paramount importance in heterocyclic chemistry as three-carbon building blocks. In a very efficient manner, they can be easily generated by palladium-copper catalyzed reactions: ynones are formed from acid chlorides and terminal alkynes, and chalcones are synthesized in the sense of a coupling-isomerization (CI) sequence from (hetero)aryl halides and propargyl alcohols. Mild reaction conditions now open entries to sequential and consecutive transformations to heterocycles, such as furans, 3-halo furans, pyrroles, pyrazoles, substituted and annelated pyridines, annelated thiopyranones, pyridimines, meridianins, benzoheteroazepines and tetrahydro-β-carbolines, by consecutive coupling-cyclocondensation or CI-cyclocondensation sequences, as new diversity oriented routes to heterocycles. Domino reactions based upon the coupling-isomerization reaction (CIR) have been probed in the synthesis of antiparasital 2-substituted quinoline derivatives and highly luminescent spiro-benzofuranones and spiro-indolones.

  8. Molecular time-course and the metabolic basis of entry into dauer in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Pan-Young Jeong

    Full Text Available When Caenorhabditis elegans senses dauer pheromone (daumone, signaling inadequate growth conditions, it enters the dauer state, which is capable of long-term survival. However, the molecular pathway of dauer entry in C. elegans has remained elusive. To systematically monitor changes in gene expression in dauer paths, we used a DNA microarray containing 22,625 gene probes corresponding to 22,150 unique genes from C. elegans. We employed two different paths: direct exposure to daumone (Path 1 and normal growth media plus liquid culture (Path 2. Our data reveal that entry into dauer is accomplished through the multi-step process, which appears to be compartmentalized in time and according to metabolic flux. That is, a time-course of dauer entry in Path 1 shows that dauer larvae formation begins at post-embryonic stage S4 (48 h and is complete at S6 (72 h. Our results also suggest the presence of a unique adaptive metabolic control mechanism that requires both stage-specific expression of specific genes and tight regulation of different modes of fuel metabolite utilization to sustain the energy balance in the context of prolonged survival under adverse growth conditions. It is apparent that worms entering dauer stage may rely heavily on carbohydrate-based energy reserves, whereas dauer larvae utilize fat or glyoxylate cycle-based energy sources. We created a comprehensive web-based dauer metabolic database for C. elegans (www.DauerDB.org that makes it possible to search any gene and compare its relative expression at a specific stage, or evaluate overall patterns of gene expression in both paths. This database can be accessed by the research community and could be widely applicable to other related nematodes as a molecular atlas.

  9. The Antartic Ice Borehole Probe

    Science.gov (United States)

    Behar, A.; Carsey, F.; Lane, A.; Engelhardt, H.

    2000-01-01

    The Antartic Ice Borehole Probe mission is a glaciological investigation, scheduled for November 2000-2001, that will place a probe in a hot-water drilled hole in the West Antartic ice sheet. The objectives of the probe are to observe ice-bed interactions with a downward looking camera, and ice inclusions and structure, including hypothesized ice accretion, with a side-looking camera.

  10. Analysis of limited-entry well tests in layered reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, M.R.; Naismith, J.D.A.; Gunasekera, D.L.; Fitzpatrick, A.J.

    1994-12-31

    Vertical permeability, often a key parameter in reservoir engineering, can be calculated from the analysis of a limited entry pressure transient. Analytical solutions for limited entry welltests, where a fraction of the reservoir interval is perforated, have been available in the literature for some time. This paper considers the evaluation of limited entry welltests in heterogeneous layered formations. A number of field examples have been analyzed using both conventional analytical techniques and a new general purpose numerical welltest analysis application. The examples show that in layered formations vertical permeability can be significantly under estimated by conventional analytical analysis.

  11. Predicting academic outcomes in an Australian graduate entry medical programme.

    Science.gov (United States)

    Puddey, Ian B; Mercer, Annette

    2014-02-15

    Predictive validity studies for selection criteria into graduate entry courses in Australia have been inconsistent in their outcomes. One of the reasons for this inconsistency may have been failure to have adequately considered background disciplines of the graduates as well as other potential confounding socio-demographic variables that may influence academic performance. Graduate entrants into the MBBS at The University of Western Australia between 2005 and 2012 were studied (N = 421). They undertook a 6-month bridging course, before joining the undergraduate-entry students for Years 3 through 6 of the medical course. Students were selected using their undergraduate Grade Point Average (GPA), Graduate Australian Medical School Admissions Test scores (GAMSAT) and a score from a standardised interview. Students could apply from any background discipline and could also be selected through an alternative rural entry pathway again utilising these 3 entry scores. Entry scores, together with age, gender, discipline background, rural entry status and a socioeconomic indicator were entered into linear regression models to determine the relative influence of each predictor on subsequent academic performance in the course. Background discipline, age, gender and selection through the rural pathway were variously related to each of the 3 entry criteria. Their subsequent inclusion in linear regression models identified GPA at entry, being from a health/allied health background and total GAMSAT score as consistent independent predictors of stronger academic performance as measured by the weighted average mark for the core units completed throughout the course. The Interview score only weakly predicted performance later in the course and mainly in clinically-based units. The association of total GAMSAT score with academic performance was predominantly dictated by the score in GAMSAT Section 3 (Reasoning in the biological and physical sciences) with Section 1 (Reasoning in the

  12. Fluctuations of Matrix Entries of Regular Functions of Wigner Matrices

    CERN Document Server

    Pizzo, Alessandro; Soshnikov, Alexander

    2011-01-01

    We study the fluctuations of the matrix entries of regular functions of Wigner random matrices in the limit when the matrix size goes to infinity. In the case of the Gaussian ensembles (GOE and GUE) this problem was considered by A.Lytova and L.Pastur in J. Stat. Phys., v.134, 147-159 (2009). Our results are valid provided the off-diagonal matrix entries have finite fourth moment, the diagonal matrix entries have finite third moment, and the test functions have four continuous derivatives in a neighborhood of the support of the Wigner semicircle law.

  13. Japanese subsidiaries in the European Union: Entry modes and performance

    Directory of Open Access Journals (Sweden)

    David Tanganelli

    2014-12-01

    Full Text Available Japanese Foreign Direct Investment (FDI in the European Union and its performance were analysed in this work. Three different FDI or entry modes used by Japanese companies to enter the European market were compared, and the presence of a relationship between the selected entry mode and the performance of the subsidiary was investigated. We found that more than half of the Japanese investments in Europe took the form of new ventures, approximately 40% were joint ventures and less than 6% were acquisitions. We found that no specific entry mode performed better than another.

  14. Lamiridosins, hepatitis C virus entry inhibitors from Lamium album.

    Science.gov (United States)

    Zhang, Hongjie; Rothwangl, Katharina; Mesecar, Andrew D; Sabahi, Ali; Rong, Lijun; Fong, Harry H S

    2009-12-01

    Phytochemical study of the aqueous extract of the flowering tops of Lamium album led to identification of the antiviral iridoid isomers lamiridosins A and B (1, 2). These compounds were found to significantly inhibit hepatitis C virus entry (IC(50) 2.31 muM) in vitro. Studies of 14 iridoid analogues showed that, while the parent iridoid glucosides demonstrated no anti-HCV entry activity, the aglycones of shanzhiside methyl ester (4), loganin (5), loganic acid (6), geniposide (10), verbenalin (12), eurostoside (15), and picroside II (17) exhibited significant anti-HCV entry and anti-infectivity activities.

  15. Comparable stocks, boundedly rational stock markets and IPO entry rates.

    Directory of Open Access Journals (Sweden)

    Jay Chok

    Full Text Available In this study, we examine how initial public offerings (IPO entry rates are affected when stock markets are boundedly rational and IPO firms infer information from their counterparts in the market. We hypothesize a curvilinear relationship between the number of comparable stocks and initial public offerings (IPO entry rates into the NASDAQ Stock Exchange. Furthermore, we argue that trading volume and changes in stock returns partially mediates the relationship between the number of comparable stocks and IPO entry rates. The statistical evidence provides strong support for the hypotheses.

  16. Physics-Based Modeling of Meteor Entry and Breakup

    Science.gov (United States)

    Prabhu, Dinesh K.; Agrawal, Parul; Allen, Gary A., Jr.; Bauschlicher, Charles W., Jr.; Brandis, Aaron M.; Chen, Yih-Kang; Jaffe, Richard L.; Palmer, Grant E.; Saunders, David A.; Stern, Eric C.; Tauber, Michael E.; Venkatapathy, Ethiraj

    2015-01-01

    A new research effort at NASA Ames Research Center has been initiated in Planetary Defense, which integrates the disciplines of planetary science, atmospheric entry physics, and physics-based risk assessment. This paper describes work within the new program and is focused on meteor entry and breakup.Over the last six decades significant effort was expended in the US and in Europe to understand meteor entry including ablation, fragmentation and airburst (if any) for various types of meteors ranging from stony to iron spectral types. These efforts have produced primarily empirical mathematical models based on observations. Weaknesses of these models, apart from their empiricism, are reliance on idealized shapes (spheres, cylinders, etc.) and simplified models for thermal response of meteoritic materials to aerodynamic and radiative heating. Furthermore, the fragmentation and energy release of meteors (airburst) is poorly understood.On the other hand, flight of human-made atmospheric entry capsules is well understood. The capsules and their requisite heatshields are designed and margined to survive entry. However, the highest speed Earth entry for capsules is 13 kms (Stardust). Furthermore, Earth entry capsules have never exceeded diameters of 5 m, nor have their peak aerothermal environments exceeded 0.3 atm and 1 kW/sq cm. The aims of the current work are: (i) to define the aerothermal environments for objects with entry velocities from 13 to 20 kms; (ii) to explore various hypotheses of fragmentation and airburst of stony meteors in the near term; (iii) to explore the possibility of performing relevant ground-based tests to verify candidate hypotheses; and (iv) to quantify the energy released in airbursts. The results of the new simulations will be used to anchor said risk assessment analyses. With these aims in mind, state-of-the-art entry capsule design tools are being extended for meteor entries. We describe: (i) applications of current simulation tools to

  17. The Effect of Diffusional Transport and Surface Catalysis on the Aerothermodynamic Heating for Martian Atmospheric Entry

    Science.gov (United States)

    Henline, William D.; Papadopoulos, Periklis; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    For the reentry heating of 70-degree blunt sphere-cones entering Mars at velocities in excess of 6 km/sec, a study was performed to determine the magnitude of both convective and catalytic heating on the cone forebody. Case studies of the peak heating conditions for the current NASA Mars Pathfinder entry probe, as well as the peak heating conditions of the proposed NASA Mars 2001 aerobraking orbiter mission were performed. Since the actual behavior of the chemical recombination of Mars atmosphere hypersonic shock layer species on heat shield materials is not known, and no experimental studies of any consequence have been done to determine surface reaction rates for the CO2 system, a parametric analysis of various reaction schemes and surface catalytic mechanistic models was performed. In many cases the actual Mars entry probe will have a heat shield composed of an ablative material which can either partially or completely preclude the existence of catalytic surface recombination phenomena. The extent of this blockage effect has not been examined at this time and is not considered in this effort. Instead only non-ablative computations are performed to separately evaluate the full extent of the surface catalysis and related diffusional phenomena. Parametric studies include peak heating point comparisons of non-catalytic, partially catalytic and fully catalytic total surface heat transfer for three difference surface recombination catalytic mechanisms (with and without simultaneous CO + O and O + O recombination) as well as with different species diffusion models. Diffusion model studies include constant Schmidt number (equal diffusivities) and the bifurcation, approximate multi-component diffusion model. Since the gas phase reaction kinetics for the Mars CO2 based atmosphere have also not been validated, the effect of two different (fast and slow) sets of gas kinetics on heat transfer is presented.

  18. Survey of the supporting research and technology for the thermal protection of the Galileo Probe

    Science.gov (United States)

    Howe, J. T.; Pitts, W. C.; Lundell, J. H.

    1981-01-01

    The Galileo Probe, which is scheduled to be launched in 1985 and to enter the hydrogen-helium atmosphere of Jupiter up to 1,475 days later, presents thermal protection problems that are far more difficult than those experienced in previous planetary entry missions. The high entry speed of the Probe will cause forebody heating rates orders of magnitude greater than those encountered in the Apollo and Pioneer Venus missions, severe afterbody heating from base-flow radiation, and thermochemical ablation rates for carbon phenolic that rival the free-stream mass flux. This paper presents a comprehensive survey of the experimental work and computational research that provide technological support for the Probe's heat-shield design effort. The survey includes atmospheric modeling; both approximate and first-principle computations of flow fields and heat-shield material response; base heating; turbulence modelling; new computational techniques; experimental heating and materials studies; code validation efforts; and a set of 'consensus' first-principle flow-field solutions through the entry maneuver, with predictions of the corresponding thermal protection requirements.

  19. Modulation of Calcium Entry by Mitochondria.

    Science.gov (United States)

    Fonteriz, Rosalba; Matesanz-Isabel, Jessica; Arias-Del-Val, Jessica; Alvarez-Illera, Pilar; Montero, Mayte; Alvarez, Javier

    2016-01-01

    The role of mitochondria in intracellular Ca(2+) signaling relies mainly in its capacity to take up Ca(2+) from the cytosol and thus modulate the cytosolic [Ca(2+)]. Because of the low Ca(2+)-affinity of the mitochondrial Ca(2+)-uptake system, this organelle appears specially adapted to take up Ca(2+) from local high-Ca(2+) microdomains and not from the bulk cytosol. Mitochondria would then act as local Ca(2+) buffers in cellular regions where high-Ca(2+) microdomains form, that is, mainly close to the cytosolic mouth of Ca(2+) channels, both in the plasma membrane and in the endoplasmic reticulum (ER). One of the first targets proposed already in the 1990s to be regulated in this way by mitochondria were the store-operated Ca(2+) channels (SOCE). Mitochondria, by taking up Ca(2+) from the region around the cytosolic mouth of the SOCE channels, would prevent its slow Ca(2+)-dependent inactivation, thus keeping them active for longer. Since then, evidence for this mechanism has accumulated mainly in immunitary cells, where mitochondria actually move towards the immune synapse during T cell activation. However, in many other cell types the available data indicate that the close apposition between plasma and ER membranes occurring during SOCE activation precludes mitochondria from getting close to the Ca(2+)-entry sites. Alternative pathways for mitochondrial modulation of SOCE, both Ca(2+)-dependent and Ca(2+)-independent, have also been proposed, but further work will be required to elucidate the actual mechanisms at work. Hopefully, the recent knowledge of the molecular nature of the mitochondrial Ca(2+) uniporter will allow soon more precise studies on this matter.

  20. Micro scanning probes

    CERN Document Server

    Niblock, T

    2001-01-01

    This thesis covers the design methodology, theory, modelling, fabrication and evaluation of a Micro-Scanning-Probe. The device is a thermally actuated bimorph quadrapod fabricated using Micro Electro Mechanical Systems technology. A quadrapod is a structure with four arms, in this case a planar structure with the four arms forming a cross which is dry etched out of a silicon diaphragm. Each arm has a layer of aluminium deposited on it forming a bimorph. Through heating each arm actuation is achieved in the plane of the quadrapod and the direction normal to it. Fabrication of the device has required the development of bulk micromachining techniques to handle post CMOS fabricated wafers and the patterning of thickly sputtered aluminium in bulk micro machined cavities. CMOS fabrication techniques were used to incorporate diodes onto the quadrapod arms for temperature measurement of the arms. Fine tungsten and silicon tips have also been fabricated to allow tunnelling between the tip and the platform at the centr...

  1. Cosmological Probes for Supersymmetry

    Directory of Open Access Journals (Sweden)

    Maxim Khlopov

    2015-05-01

    Full Text Available The multi-parameter character of supersymmetric dark-matter models implies the combination of their experimental studies with astrophysical and cosmological probes. The physics of the early Universe provides nontrivial effects of non-equilibrium particles and primordial cosmological structures. Primordial black holes (PBHs are a profound signature of such structures that may arise as a cosmological consequence of supersymmetric (SUSY models. SUSY-based mechanisms of baryosynthesis can lead to the possibility of antimatter domains in a baryon asymmetric Universe. In the context of cosmoparticle physics, which studies the fundamental relationship of the micro- and macro-worlds, the development of SUSY illustrates the main principles of this approach, as the physical basis of the modern cosmology provides cross-disciplinary tests in physical and astronomical studies.

  2. Cosmological Probes for Supersymmetry

    CERN Document Server

    Khlopov, Maxim

    2015-01-01

    The multi-parameter character of supersymmetric dark-matter models implies the combination of their experimental studies with astrophysical and cosmological probes. The physics of the early Universe provides nontrivial effects of non-equilibrium particles and primordial cosmological structures. Primordial black holes (PBHs) are a profound signature of such structures that may arise as a cosmological consequence of supersymmetric (SUSY) models. SUSY-based mechanisms of baryosynthesis can lead to the possibility of antimatter domains in a baryon asymmetric Universe. In the context of cosmoparticle physics, which studies the fundamental relationship of the micro- and macro-worlds, the development of SUSY illustrates the main principles of this approach, as the physical basis of the modern cosmology provides cross-disciplinary tests in physical and astronomical studies.

  3. Spontaneous Symmetry Probing

    CERN Document Server

    Nicolis, Alberto

    2011-01-01

    For relativistic quantum field theories, we consider Lorentz breaking, spatially homogeneous field configurations or states that evolve in time along a symmetry direction. We dub this situation "spontaneous symmetry probing" (SSP). We mainly focus on internal symmetries, i.e. on symmetries that commute with the Poincare group. We prove that the fluctuations around SSP states have a Lagrangian that is explicitly time independent, and we provide the field space parameterization that makes this manifest. We show that there is always a gapless Goldstone excitation that perturbs the system in the direction of motion in field space. Perhaps more interestingly, we show that if such a direction is part of a non-Abelian group of symmetries, the Goldstone bosons associated with spontaneously broken generators that do not commute with the SSP one acquire a gap, proportional to the SSP state's "speed". We outline possible applications of this formalism to inflationary cosmology.

  4. New probe of naturalness.

    Science.gov (United States)

    Craig, Nathaniel; Englert, Christoph; McCullough, Matthew

    2013-09-20

    Any new scalar fields that perturbatively solve the hierarchy problem by stabilizing the Higgs boson mass also generate new contributions to the Higgs boson field-strength renormalization, irrespective of their gauge representation. These new contributions are physical, and in explicit models their magnitude can be inferred from the requirement of quadratic divergence cancellation; hence, they are directly related to the resolution of the hierarchy problem. Upon canonically normalizing the Higgs field, these new contributions lead to modifications of Higgs couplings that are typically great enough that the hierarchy problem and the concept of electroweak naturalness can be probed thoroughly within a precision Higgs boson program. Specifically, at a lepton collider this can be achieved through precision measurements of the Higgs boson associated production cross section. This would lead to indirect constraints on perturbative solutions to the hierarchy problem in the broadest sense, even if the relevant new fields are gauge singlets.

  5. Advanced Langmuir Probe (LP)

    Science.gov (United States)

    Voronka, N. R.; Block, B. P.; Carignan, G. R.

    1991-01-01

    The dynamic response of the MK-2 version of the Langmuir probe amplifier was studied. The settling time of the step response is increased by: (1) stray node-to-ground capacitance at series connections between high value feedback resistors; and (2) input capacitance due to the input cable, FET switches, and input source follower. The stray node-to-ground capacitances can be reduced to tolerable levels by elevating the string of feedback resistors above the printing board. A new feedback network was considered, with promising results. The design uses resistances having much lower nominal values, thereby minimizing the effect of stray capacitances. Faster settling times can be achieved by using an operational amplifier having a higher gain-bandwidth product.

  6. 19 CFR 122.26 - Entry and clearance.

    Science.gov (United States)

    2010-04-01

    ... AIR COMMERCE REGULATIONS Private Aircraft § 122.26 Entry and clearance. Private aircraft, as defined... information as set forth in § 122.22(c), and grants electronic clearance via electronic mail or telephone....

  7. 27 CFR 22.25 - Right of entry and examination.

    Science.gov (United States)

    2010-04-01

    ... BUREAU, DEPARTMENT OF THE TREASURY LIQUORS DISTRIBUTION AND USE OF TAX-FREE ALCOHOL Administrative Provisions Authorities § 22.25 Right of entry and examination. An appropriate TTB officer may enter,...

  8. Multidisciplinary Design Under Uncertainty for Entry Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The physical difficulty of designing entry vehicles originates from the large degree of coupling between the various disciplines involved in the design. Every...

  9. Higher Entry Threshold of the Secondary Lead Industry

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>According to news posted on the Ministry of Industry and Information Technology’s website on September 5,the MIIT and the Ministry of Environmental Protection recently jointly issued the Entry Conditions of the Secondary

  10. Orion Entry Performance-Based Center-of-Gravity Box

    Science.gov (United States)

    Rea, Jeremy R.

    2010-01-01

    The Orion capsule has many performance requirements for its atmospheric entry trajectory. Requirements on landing accuracy, maximum heating rate, total heat load, propellant usage, and sensed acceleration must all be satised. It is desired to define a methodology to translate the many performance requirements for an atmospheric entry trajectory into language easily understood by vehicle designers in terms of an allowable center-of-gravity box. This is possible by noting that most entry performance parameters for a capsule vehicle are mainly determined by the lift-to-drag ratio of the vehicle. However, the lift-to- drag ratio should be considered a probabilistic quantity rather than deterministic, where variations in the lift-to-drag are caused by both aerodynamic and center-of-gravity un- certainties. This paper discusses the technique used by the Orion program to define the allowable dispersions in center-of-gravity to achieve the desired entry performance while accounting for aerodynamic uncertainty.

  11. 33 CFR 151.08 - Denial of entry.

    Science.gov (United States)

    2010-07-01

    ... BALLAST WATER Implementation of MARPOL 73/78 and the Protocol on Environmental Protection to the Antarctic Treaty as it Pertains to Pollution from Ships General § 151.08 Denial of entry. (a) Unless a ship...

  12. The state-of-the-art port of entry workshop

    Energy Technology Data Exchange (ETDEWEB)

    Godfrey, B.

    1995-05-01

    The increased demand for freight movements through international ports of entry and the signing of the North American Free Trade Agreement (NAFTA) have increased freight traffic at border ports of entry. The State-of-the-Art Port of Entry Workshop initiated a dialogue among technologists and stakeholders to explore the potential uses of technology at border crossings and to set development priorities. International ports of entry are both information and labor intensive, and there are many promising technologies that could be used to provide timely information and optimize inspection resources. Participants universally held that integration of technologies and operations is critical to improving port services. A series of Next Steps was developed to address stakeholder issues and national priorities, such as the National Transportation Policy and National Drug Policy. This report documents the views of the various stakeholders and technologists present at the workshop and outlines future directions of study.

  13. Adapting Mars Entry, Descent and Landing System for Earth

    Science.gov (United States)

    Heilimo, J.; Harri, A.-M.; Aleksashkin, S.; Koryanov, V.; Guerrero, H.; Schmidt, W.; Haukka, H.; Finchenko, V.; Martynov, M.; Ostresko, B.; Ponomarenko, A.; Kazakovtsev, V.; Arruego, I.; Martin, S.; Siili, T.

    2013-09-01

    In 2001 - 2011 an inflatable Entry, Descent and Landing System (EDLS) for Martian atmosphere was developed by FMI and the MetNet team. This MetNet Mars Lander EDLS is used in both the initial deceleration during atmospheric entry and in the final deceleration before the semi-hard impact of the penetrator to Martian surface. The EDLS design is ingenious and its applicability to Earth's atmosphere is studied in the on-going project. In particular, the behavior of the system in the critical transonic aerodynamic (from hypersonic to subsonic) regime will be investigated. This project targets to analyze and test the transonic behavior of this compact and light weight payload entry system to Earth's atmosphere [1]. Scaling and adaptation for terrestrial atmospheric conditions, instead of a completely new design, is a favorable approach for providing a new re-entry vehicle for terrestrial space applications.

  14. Multidisciplinary Design Under Uncertainty for Entry Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The physical difficulty of designing entry vehicles originates from the large degree of coupling between the various disciplines involved in the design. Every...

  15. Advanced Metal Rubber Sensors for Hypersonic Decelerator Entry Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NanoSonic proposes to design and develop light-weight, low-modulus, and durable Metal Rubber™ sensors for aeroelastic analysis of Hypersonic Decelerator Entry...

  16. Simulation of the ATV Re-Entry Obsrvations

    Science.gov (United States)

    Bastida Virgili, B.; Krag, H.; Lips, T.; De Pasquale, E.

    2010-09-01

    The first ATV was launched on 9th March 2008 and, after a successful mission, the last phase was a controlled destructive re-entry on 29th September 2008, shortly after 13:30 UTC, in which the remains of the ATV and its load fell into the South Pacific Ocean. In order to better understand the re-entry processes, an insitu optical observation campaign was launched to record and analyze the ATV controlled re-entry with several instruments on board of two airplanes and also from the ISS. This observation campaign was successful and triggered several different still-ongoing studies on the extraction and analysis of data to draw conclusions on the adequacy of the re-entry break-up and explosion models used for the safety analysis of the ATV re-entry. This paper addresses the validation process for ESA’s model for re-entry survivability and on-ground risk assessment for explosive re-entry events using the observation data. The underlying rationale is to improve the models for the benefit of planning and execution of future controlled re-entries and in risk calculation in case of uncontrolled ones. The re-entry trajectory of the ATV, the explosive event and the trajectories of the fragments are simulated with the existing ESA tools and the EVOLVE explosion model. Additional software has been developed to simulate airborne sensor field of view(FOV) crossings based on the aircraft trajectories, attitude profile, sensor mounts and FOVs. Sensor performance and object radiation are modeled in order to generate synthetic images for the different sensors in the ISS and the two airplanes. These synthetic images and synthetic videos are compared with the available reentry observations of the ATV. This paper will present the software and techniques to generate synthetic imagery. It will give results of the comparison between the simulated and the real trajectories and fragmentation and explain the subsequent validation process of the ESA re-entry tools and the potential

  17. Predicting small molecule fluorescent probe localization in living cells using QSAR modeling. 1. Overview and models for probes of structure, properties and function in single cells.

    Science.gov (United States)

    Horobin, R W; Rashid-Doubell, F; Pediani, J D; Milligan, G

    2013-11-01

    Small molecule fluorochromes (synonyms: biosensors, chemosensors, fluorescent probes, vital stains) are widely used to investigate the structure, composition, physicochemical properties and biological functions of living cells, tissues and organisms. Selective entry and accumulation within particular cells and cellular structures are key processes for achieving these diverse objectives. Despite the complexities, probes routinely are applied using standard protocols, often without experimenter awareness of what factors that control accumulation and localization. The mechanisms of many such selective accumulations, however, now are known. Moreover, the influence of physicochemical properties of probes on their uptake and localization often can be defined numerically, hence predicted, using quantitative structure activity relations (QSAR) models with its required numerical structure parameters (or "descriptors"). The state of the art of this approach is described. Available QSAR models are summarized for uptake into cells and localization in the cytosol, endoplasmic reticulum, generic biomembranes, Golgi apparatus, lipid droplets, lysosomes/endosomes, mitochondria, eukaryotic nuclei (histones and DNA), plasma membrane, and ribosomal RNA (cytoplasmic and nucleolar). Integration of such core models to both aid understanding and troubleshooting of current fluorescent probes and to assist the design of novel probes is outlined and illustrated using case examples. Limitations and generic problems arising with this approach and comments on application of such approaches to xenobiotics other than probes, e.g., drugs and herbicides, together with a brief note about an alternative approach to prediction, are given.

  18. FDI In India : Determinents Of Entry Modes In India

    OpenAIRE

    Jain, Gaurav

    2003-01-01

    Although cultural distance between countries have gained a lot of attention in the FDI literature but impact on cultural distance on entry mode has recently been extensively researched, after Kogut and Singh introduced the simple measure to calculate cultural distance between the countries. This dissertation tests the proposition that do cultural distance, Sector, or Nationality affect the entry mode strategies of multinational firms when they enter foreign countries. I focus my study by conc...

  19. Lipoprotein Receptors Redundantly Participate in Entry of Hepatitis C Virus.

    Directory of Open Access Journals (Sweden)

    Satomi Yamamoto

    2016-05-01

    Full Text Available Scavenger receptor class B type 1 (SR-B1 and low-density lipoprotein receptor (LDLR are known to be involved in entry of hepatitis C virus (HCV, but their precise roles and their interplay are not fully understood. In this study, deficiency of both SR-B1 and LDLR in Huh7 cells was shown to impair the entry of HCV more strongly than deficiency of either SR-B1 or LDLR alone. In addition, exogenous expression of not only SR-B1 and LDLR but also very low-density lipoprotein receptor (VLDLR rescued HCV entry in the SR-B1 and LDLR double-knockout cells, suggesting that VLDLR has similar roles in HCV entry. VLDLR is a lipoprotein receptor, but the level of its hepatic expression was lower than those of SR-B1 and LDLR. Moreover, expression of mutant lipoprotein receptors incapable of binding to or uptake of lipid resulted in no or slight enhancement of HCV entry in the double-knockout cells, suggesting that binding and/or uptake activities of lipid by lipoprotein receptors are essential for HCV entry. In addition, rescue of infectivity in the double-knockout cells by the expression of the lipoprotein receptors was not observed following infection with pseudotype particles bearing HCV envelope proteins produced in non-hepatic cells, suggesting that lipoproteins associated with HCV particles participate in the entry through their interaction with lipoprotein receptors. Buoyant density gradient analysis revealed that HCV utilizes these lipoprotein receptors in a manner dependent on the lipoproteins associated with HCV particles. Collectively, these results suggest that lipoprotein receptors redundantly participate in the entry of HCV.

  20. Lipoprotein Receptors Redundantly Participate in Entry of Hepatitis C Virus.

    Science.gov (United States)

    Yamamoto, Satomi; Fukuhara, Takasuke; Ono, Chikako; Uemura, Kentaro; Kawachi, Yukako; Shiokawa, Mai; Mori, Hiroyuki; Wada, Masami; Shima, Ryoichi; Okamoto, Toru; Hiraga, Nobuhiko; Suzuki, Ryosuke; Chayama, Kazuaki; Wakita, Takaji; Matsuura, Yoshiharu

    2016-05-01

    Scavenger receptor class B type 1 (SR-B1) and low-density lipoprotein receptor (LDLR) are known to be involved in entry of hepatitis C virus (HCV), but their precise roles and their interplay are not fully understood. In this study, deficiency of both SR-B1 and LDLR in Huh7 cells was shown to impair the entry of HCV more strongly than deficiency of either SR-B1 or LDLR alone. In addition, exogenous expression of not only SR-B1 and LDLR but also very low-density lipoprotein receptor (VLDLR) rescued HCV entry in the SR-B1 and LDLR double-knockout cells, suggesting that VLDLR has similar roles in HCV entry. VLDLR is a lipoprotein receptor, but the level of its hepatic expression was lower than those of SR-B1 and LDLR. Moreover, expression of mutant lipoprotein receptors incapable of binding to or uptake of lipid resulted in no or slight enhancement of HCV entry in the double-knockout cells, suggesting that binding and/or uptake activities of lipid by lipoprotein receptors are essential for HCV entry. In addition, rescue of infectivity in the double-knockout cells by the expression of the lipoprotein receptors was not observed following infection with pseudotype particles bearing HCV envelope proteins produced in non-hepatic cells, suggesting that lipoproteins associated with HCV particles participate in the entry through their interaction with lipoprotein receptors. Buoyant density gradient analysis revealed that HCV utilizes these lipoprotein receptors in a manner dependent on the lipoproteins associated with HCV particles. Collectively, these results suggest that lipoprotein receptors redundantly participate in the entry of HCV.

  1. Fractionation and fragmentation of glass cosmic spherules during atmospheric entry

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; ShyamPrasad, M.; Babu, E.V.S.S.K.; VijayaKumar, T.; Feng, W.; Plane, J.M.C.

    of these elements during atmospheric entry (Fig. 7). However, the bulk chemical compositions of Al, Ca, Mg, Fe are generally CI-like except for some volatile elements, which rules out an achondritic parent body. Taylor et al. (2007) reported anorthite with low... entry with the exception of the particles having high velocities and low zenith angles (Love and Brownlee, 1991; Vondrak et al., 2008). Larger micrometeorites have undergone ablation leading to siderophile and volatile element depletion, and mass...

  2. The choice of foreign entry modes in a control perspective

    DEFF Research Database (Denmark)

    Boyd, Britta; Dyhr Ulrich, Anna Marie; Hollensen, Svend

    The aim of this article is to investigate the choice of entry modes for international markets in a control perspective. A survey from The Confederation of Danish Industry with 234 Danish small- and medium sized enterprises served as a data base. The entry modes are categorized into three groups d...... turnover. The factors: personal networks and the interruption of the international activities were the most significant factors for the choice of intermediate mode (joint ventures and strategic alliances)....

  3. Principles of safe abdominal entry in laparoscopic gynecologic surgery

    Directory of Open Access Journals (Sweden)

    Jongrak Thepsuwan

    2013-11-01

    Full Text Available Laparoscopic gynecologic surgery has been widely used with a range of benefits. However, there are complications that are related to the abdominal entry process. Serious complications are gastrointestinal tract and major blood vessel injuries. This review introduces the recent available literature to prevent and eliminate the laparoscopic entry complications. The open entry technique is associated with a significant reduction of failed entry, compared to the closed entry technique; however there is no difference in the incidence of visceral or vascular injury. Laparoscopic entry by the left upper abdomen (i.e., Palmer's point or the middle upper abdomen (i.e., the Lee-Huang point could be considered in patients with suspected periumbilical adhesions or a history of umbilical hernia, or after three failed attempts of insufflation at the umbilicus. The Lee-Huang point has its own benefit for the operative laparoscopy in large pelvic pathologies and gynecology malignancy cases. The angle of Veress needle insertion varies from 45° in nonobese women to 90° in extraordinarily obese women. The high intra-peritoneal pressure entries, which range from 20 mmHg to 25 mmHg, minimize the risk of vascular injury. Therefore, this will not adversely affect the cardiopulmonary function in healthy women. The Veress intraperitoneal pressure (<10 mmHg is a reliable indicator of correct intraperitoneal placement of the Veress needle. The elevation of anterior abdominal wall for placement of a Veress needle increases the risks of failed entry and shows no advantage in regard to vascular or visceral complications. Surgeons should continue to increase their knowledge of anatomy, their training, and their experience to decrease laparoscopic complications.

  4. 19 CFR 147.44 - Entry for another fair.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Entry for another fair. 147.44 Section 147.44 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) TRADE FAIRS Disposition of Articles Entered for Fairs § 147.44 Entry for another fair. Articles entered for a fair which are to...

  5. Entry ramps in the Nagel-Schreckenberg model

    DEFF Research Database (Denmark)

    Pedersen, Morten Monrad; Ruhoff, Peder Thusgaard

    2002-01-01

    This paper describes a way of including entry ramps in the Nagel-Schreckenberg traffic model. The idea is to place what are called shadow cars on a highway next to cars on entry ramps, which enables the drivers to take ramp cars into account. The model is shown to capture important real......-life traffic phenomena that have not been included in previous models. Furthermore, it is demonstrated that the desirable properties of the Nagel-Schreckenberg model are retained....

  6. Fragmentation of weak non-ablating objects during entry

    Energy Technology Data Exchange (ETDEWEB)

    Canavan, G.H.

    1997-04-01

    Fragmentation of objects during entry can be treated with developed models of breakup, fragment cascade, separation, and deceleration. The results reduce to those derived earlier for strong objects. Model predictions are in agreement with the key features of numerical simulations. Model equations can be inverted analytically to infer object size, entry speed, and strength from measurements of peak power and altitude and fragmentation altitude or time.

  7. Synthesis of Photoactivatable Phospholipidic Probes

    Institute of Scientific and Technical Information of China (English)

    Qing PENG; Fan Qi QU; Yi XIA; Jie Hua ZHOU; Qiong You WU; Ling PENG

    2005-01-01

    We synthesized and characterized photoactivatable phospholipidic probes 1-3. These probes have the perfluorinated aryl azide function at the polar head of phospholipid. They are stable in dark and become highly reactive upon photoirradiation. The preliminary results suggest that they are promising tools to study the topology of membrane proteins and protein-lipid interactions using photolabeling approach.

  8. Non-inductive current probe

    DEFF Research Database (Denmark)

    Bak, Christen Kjeldahl

    1977-01-01

    The current probe described is a low-cost, shunt resistor for monitoring current pulses in e.g., pulsed lasers. Rise time is......The current probe described is a low-cost, shunt resistor for monitoring current pulses in e.g., pulsed lasers. Rise time is...

  9. Using analytic network process for evaluating mobile text entry methods.

    Science.gov (United States)

    Ocampo, Lanndon A; Seva, Rosemary R

    2016-01-01

    This paper highlights a preference evaluation methodology for text entry methods in a touch keyboard smartphone using analytic network process (ANP). Evaluation of text entry methods in literature mainly considers speed and accuracy. This study presents an alternative means for selecting text entry method that considers user preference. A case study was carried out with a group of experts who were asked to develop a selection decision model of five text entry methods. The decision problem is flexible enough to reflect interdependencies of decision elements that are necessary in describing real-life conditions. Results showed that QWERTY method is more preferred than other text entry methods while arrangement of keys is the most preferred criterion in characterizing a sound method. Sensitivity analysis using simulation of normally distributed random numbers under fairly large perturbation reported the foregoing results reliable enough to reflect robust judgment. The main contribution of this paper is the introduction of a multi-criteria decision approach in the preference evaluation of text entry methods.

  10. Effects ok ikea's entry into a furniture production cluster

    Directory of Open Access Journals (Sweden)

    Vasco Eiriz

    2016-04-01

    Full Text Available The entry of a multinational into a cluster, a geographic agglomeration in a given place or region of predominantly small and medium enterprises specialized in a given industry or related industries, impacts the incumbent in the cluster. Aiming to identify the main effects of a multinational entry on the firms’ strategy in a cluster, it was analyzed the entry of IKEA, a Swedish multinational, into the cluster of furniture production in Paços de Ferreira and Paredes, in Portugal. In this study, the data collection technique to access primary data was a survey. The sample has small enterprises, which is similar to the structure of firms in the studied cluster. Results show that more than half the sample thinks that the entry of the multinational had not affected them. However, the firms that acknowledge a significant impact, assess that impact as negative. The competitiveness factors that have improved more significantly after IKEA’s entry were new product development and exporting strategies. The main responses of incumbent firms to the multinational entry were internationalization and the development of generic strategies of differentiation and focus based on differentiation.

  11. Thermal Testing of Woven TPS Materials in Extreme Entry Environments

    Science.gov (United States)

    Gonzales, G.; Stackpoole, M.

    2014-01-01

    NASAs future robotic missions to Venus and outer planets, namely, Saturn, Uranus, Neptune, result in extremely high entry conditions that exceed the capabilities of current mid density ablators (PICA or Avcoat). Therefore mission planners assume the use of a fully dense carbon phenolic heatshield similar to what was flown on Pioneer Venus and Galileo. Carbon phenolic (CP) is a robust TPS however its high density and thermal conductivity constrain mission planners to steep entries, high heat fluxes, high pressures and short entry durations, in order for CP to be feasible from a mass perspective. In 2012 the Game Changing Development Program in NASAs Space Technology Mission Directorate funded NASA ARC to investigate the feasibility of a Woven Thermal Protection System to meet the needs of NASAs most challenging entry missions. The high entry conditions pose certification challenges in existing ground based test facilities. Recent updates to NASAs IHF and AEDCs H3 high temperature arcjet test facilities enable higher heatflux (2000 Wcm2) and high pressure (5 atm) testing of TPS. Some recent thermal tests of woven TPS will be discussed in this paper. These upgrades have provided a way to test higher entry conditions of potential outer planet and Venus missions and provided a baseline against carbon phenolic material. The results of these tests have given preliminary insight to sample configuration and physical recession profile characteristics.

  12. Three-stage entry game: The strategic effects of advertising

    Directory of Open Access Journals (Sweden)

    Kuzmanović Marija

    2011-01-01

    Full Text Available This paper analyzes the effects of investment in advertising in the three-stage entry game model with one incumbent and one potential entrant firm. It is shown that if a game theory is applied, under particular conditions, advertising can be used as a strategic weapon in the market entry game. Depending on the level of the advertising interaction factor, conditions for over-investment in advertising for strategic purposes are given. Furthermore, three specific cases are analyzed: strictly predatory advertising, informative advertising and the case when one firm’s advertising cannot directly influence the other firm's profit. For each of them, depending on the costs of advertising and marginal costs, equilibrium is determined, and conditions under which it is possible to deter the entry are given. It is shown that if the value of the advertising interaction factor increases, power of using advertising as a weapon to deter entry into the market decreases. Thus, in the case of informative advertising, advertising cannot be used as a tool for deterring entry into the market, while in the case of predatory advertising, it can. Also, we have proved that in the case of strictly informative advertising an over-investment never occurs, while in the two other cases, there is always over-investment either to deter or to accommodate the entry.

  13. Inhibition of influenza H7 hemagglutinin-mediated entry.

    Directory of Open Access Journals (Sweden)

    Aleksandar Antanasijevic

    Full Text Available The recent outbreak of H7N9 influenza in China is of high concern to public health. H7 hemagglutinin (HA plays a critical role in influenza entry and thus HA presents an attractive target for antivirals. Previous studies have suggested that the small molecule tert-butyl hydroquinone (TBHQ inhibits the entry of influenza H3 HA by binding to the stem loop of HA and stabilizing the neutral pH conformation of HA, thereby disrupting the membrane fusion step. Based on amino acid sequence, structure and immunogenicity, H7 is a related Group 2 HA. In this work we show, using a pseudovirus entry assay, that TBHQ inhibits H7 HA-mediated entry, as well as H3 HA-mediated entry, with an IC50 ~ 6 µM. Using NMR, we show that TBHQ binds to the H7 stem loop region. STD NMR experiments indicate that the aromatic ring of TBHQ makes extensive contact with the H7 HA surface. Limited proteolysis experiments indicate that TBHQ inhibits influenza entry by stabilizing the H7 HA neutral pH conformation. Together, this work suggests that the stem loop region of H7 HA is an attractive target for therapeutic intervention and that TBHQ, which is a widely used food preservative, is a promising lead compound.

  14. Dynamics of ambulatory surgery centers and hospitals market entry.

    Science.gov (United States)

    Housman, Michael; Al-Amin, Mona

    2013-08-01

    In this article, we investigate the diversity of healthcare delivery organizations by comparing the market determinants of hospitals entry rates with those of ambulatory surgery centers (ASCs). Unlike hospitals, ASCs is one of the growing populations of specialized healthcare delivery organizations. There are reasons to believe that firm entry patterns differ within growing organizational populations since these markets are characterized by different levels of organizational legitimacy, technological uncertainty, and information asymmetry. We compare the entry patterns of firms in a mature population of hospitals to those of firms within a growing population of ASCs. By using patient-level datasets from the state of Florida, we break down our explanatory variables by facility type (ASC vs. hospital) and utilize negative binomial regression models to evaluate the impact of niche density on ASC and hospital entry. Our results indicate that ASCs entry rates is higher in markets with overlapping ASCs while hospitals entry rates are less in markets with overlapping hospitals and ASCs. These results are consistent with the notion that firms in growing populations tend to seek out crowded markets as they compete to occupy the most desirable market segments while firms in mature populations such as general hospitals avoid direct competition.

  15. Entry and Exit Stress Variation of Cold Rolling Strip

    Institute of Scientific and Technical Information of China (English)

    WANGDong—cheng

    2012-01-01

    The shortcomings of an exit stress variation formula which has been well accepted are analyzed~ it is found that the exit stress variation formula violates the premise of the law of volume constancy. The shortcomings of an en- try stress variation formula are analyzed too, and the basic assumption of the formula is uniform exit velocity. How- ever, for a rigid-plastic material uniform exit velocity implies that the lateral distributioi1 of elongation is uniform, so the exit stress must be uniform and any type of flatness defect is impossible, which is contrary to the practice. In fact, entry and exit velocity variation influence entry and exit stress variation, and entry and exit stress variation in- fluence entry and exit velocity variation too, so a precise explicit stress variation formula cannot be got easily. Con- sidering the relationship between stress variation and velocity variation, an iteration method is presented to calculate entry and exit stress variation of cold rolling strip. To avoid divergent phenomenon of the iteration course, a relaxa- tion factor method is adopted. The calculation results are compared with the entry and exit stress variation formula commonly used by many researchers. The difference is remarkable, while the result calculated agree more well with measured result if the exit elastic recovery zone is considered. Specially, the incoming flatnessI propagate efficiency calculated ~ives a more realistic result.

  16. Nursing medication administration and workflow using computerized physician order entry.

    Science.gov (United States)

    Tschannen, Dana; Talsma, Akkeneel; Reinemeyer, Nicholas; Belt, Christine; Schoville, Rhonda

    2011-07-01

    The benefits of computerized physician order entry systems have been described widely; however, the impact of computerized physician order entry on nursing workflow and its potential for error are unclear. The purpose of this study was to determine the impact of a computerized physician order entry system on nursing workflow. Using an exploratory design, nurses employed on an adult ICU (n = 36) and a general pediatric unit (n = 50) involved in computerized physician order entry-based medication delivery were observed. Nurses were also asked questions regarding the impact of computerized physician order entry on nursing workflow. Observations revealed total time required for administering medications averaged 8.45 minutes in the ICU and 9.93 minutes in the pediatric unit. Several additional steps were required in the process for pediatric patients, including preparing the medications and communicating with patients and family, which resulted in greater time associated with the delivery of medications. Frequent barriers to workflow were noted by nurses across settings, including system issues (ie, inefficient medication reconciliation processes, long order sets requiring more time to determine medication dosage), less frequent interaction between the healthcare team, and greater use of informal communication modes. Areas for nursing workflow improvement include (1) medication reconciliation/order duplication, (2) strategies to improve communication, and (3) evaluation of the impact of computerized physician order entry on practice standards.

  17. Acceptions of the "death"entry in language dictionaries

    Directory of Open Access Journals (Sweden)

    Jessica Camara Siqueira

    2013-08-01

    Full Text Available Language dictionaries present the meaning of an entry in a way not restricted to linguistic information, since we also have interdisciplinary and contextual aspects that dialogue with socio-cultural issues in which the entry is inserted. Considering the potential character of the study of contextual meanings, the “death” entry was chosen to carry out a comparative analysis among language dictionaries. The choice was motivated by the recurrence of this entry in ancient and contemporary dictionaries, and the fact of its having a concept that allows various historical, social and ideological discussions. The goal is to reveal the different nuances of the “death” entry in language dictionaries, observing four main aspects: etymology, diachrony, synonymic construction and meaning of “death” in school dictionaries. Based on lexicographical studies of classical authors, we did a comparative analysis of meanings of “death” in different types of language dictionaries. We found that in each group dictionary we may find traces of ideological choices in the construction of the contextual meaning of the “death” entry.

  18. Cobra Probes Containing Replaceable Thermocouples

    Science.gov (United States)

    Jones, John; Redding, Adam

    2007-01-01

    A modification of the basic design of cobra probes provides for relatively easy replacement of broken thermocouples. Cobra probes are standard tube-type pressure probes that may also contain thermocouples and that are routinely used in wind tunnels and aeronautical hardware. They are so named because in side views, they resemble a cobra poised to attack. Heretofore, there has been no easy way to replace a broken thermocouple in a cobra probe: instead, it has been necessary to break the probe apart and then rebuild it, typically at a cost between $2,000 and $4,000 (2004 prices). The modified design makes it possible to replace the thermocouple, in minimal time and at relatively low cost, by inserting new thermocouple wire in a tube.

  19. Nanobits: customizable scanning probe tips

    DEFF Research Database (Denmark)

    Kumar, Rajendra; Shaik, Hassan Uddin; Sardan Sukas, Özlem

    2009-01-01

    silicon processing. Using a microgripper they were detached from an array and fixed to a standard pyramidal AFM probe or alternatively inserted into a tipless cantilever equipped with a narrow slit. The nanobit-enhanced probes were used for imaging of deep trenches, without visible deformation, wear......We present here a proof-of-principle study of scanning probe tips defined by planar nanolithography and integrated with AFM probes using nanomanipulation. The so-called 'nanobits' are 2-4 mu m long and 120-150 nm thin flakes of Si3N4 or SiO2, fabricated by electron beam lithography and standard...... or dislocation of the tips of the nanobit after several scans. This approach allows an unprecedented freedom in adapting the shape and size of scanning probe tips to the surface topology or to the specific application....

  20. Wearable probes for service design

    DEFF Research Database (Denmark)

    Mullane, Aaron; Laaksolahti, Jarmo Matti; Svanæs, Dag

    2014-01-01

    by service employees in reflecting on the delivery of a service. In this paper, we present the ‘wearable probe’, a probe concept that captures sensor data without distracting service employees. Data captured by the probe can be used by the service employees to reflect and co-reflect on the service journey......Probes are used as a design method in user-centred design to allow end-users to inform design by collecting data from their lives. Probes are potentially useful in service innovation, but current probing methods require users to interrupt their activity and are consequently not ideal for use......, helping to identify opportunities for service evolution and innovation....

  1. Electrophoresis-mass spectrometry probe

    Science.gov (United States)

    Andresen, Brian D.; Fought, Eric R.

    1987-01-01

    The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface.

  2. Mobile Probes in Mobile Learning

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Blomhøj, Ulla; Duvaa, Uffe

    as an agent for acquiring empirical data (as the situation in hitherto mobile probe settings) but was also the technological medium for which data should say something about (mobile learning). Consequently, not only the content of the data but also the ways in which data was delivered and handled, provided......In this paper experiences from using mobile probes in educational design of a mobile learning application is presented. The probing process stems from the cultural probe method, and was influenced by qualitative interview and inquiry approaches. In the project, the mobile phone was not only acting...... a valuable dimension for investigating mobile use. The data was collected at the same time as design activities took place and the collective data was analysed based on user experience goals and cognitive processes from interaction design and mobile learning. The mobile probe increased the knowledge base...

  3. Development of ethynyl-2'-deoxyuridine chemical probes for cell proliferation.

    Science.gov (United States)

    Lovitt, Carrie J; Hilko, David H; Avery, Vicky M; Poulsen, Sally-Ann

    2016-09-15

    A common method of evaluating cellular proliferation is to label DNA with chemical probes. 5-Ethynyl-2'-deoxyuridine (EdU) is a widely utilized chemical probe for labeling DNA, and upon incorporation, EdU treatment of cells is followed by a reaction with a small molecule fluorescent azide to allow detection. The limitations when using EdU include cytotoxicity and a reliance on nucleoside active transport mechanisms for entry into cells. Here we have developed six novel EdU pro-labels that consist of EdU modified with variable lipophilic acyl ester moieties. This pro-label:chemical probe relationship parallels the prodrug:drug relationship that is employed widely in medicinal chemistry. EdU and EdU pro-labels were evaluated for their labeling efficacy and cytotoxicity. Several EdU pro-label analogues incorporate into DNA at a similar level to EdU, suggesting that nucleoside transporters can be bypassed by the pro-labels. These EdU pro-labels also had reduced toxicity compared to EdU.

  4. The prion protein regulates glutamate-mediated Ca(2+) entry and mitochondrial Ca(2+) accumulation in neurons.

    Science.gov (United States)

    De Mario, Agnese; Peggion, Caterina; Massimino, Maria Lina; Viviani, Francesca; Castellani, Angela; Giacomello, Marta; Lim, Dmitry; Bertoli, Alessandro; Sorgato, Maria Catia

    2017-08-15

    The cellular prion protein (PrP(C)) whose conformational misfolding leads to the production of deadly prions, has a still-unclarified cellular function despite decades of intensive research. Following our recent finding that PrP(C) limits Ca(2+) entry via store-operated Ca(2+) channels in neurons, we investigated whether the protein could also control the activity of ionotropic glutamate receptors (iGluRs). To this end, we compared local Ca(2+) movements in primary cerebellar granule neurons and cortical neurons transduced with genetically encoded Ca(2+) probes and expressing, or not expressing, PrP(C) Our investigation demonstrated that PrP(C) downregulates Ca(2+) entry through each specific agonist-stimulated iGluR and after stimulation by glutamate. We found that, although PrP-knockout (KO) mitochondria were displaced from the plasma membrane, glutamate addition resulted in a higher mitochondrial Ca(2+) uptake in PrP-KO neurons than in their PrP(C)-expressing counterpart. This was because the increased Ca(2+) entry through iGluRs in PrP-KO neurons led to a parallel increase in Ca(2+)-induced Ca(2+) release via ryanodine receptor channels. These data thus suggest that PrP(C) takes part in the cell apparatus controlling Ca(2+) homeostasis, and that PrP(C) is involved in protecting neurons from toxic Ca(2+) overloads. © 2017. Published by The Company of Biologists Ltd.

  5. Exact probes of orientifolds

    CERN Document Server

    Fiol, Bartomeu; Torrents, Genis

    2014-01-01

    We compute the exact vacuum expectation value of circular Wilson loops for Euclidean ${\\cal N}=4$ super Yang-Mills with $G=SO(N),Sp(N)$, in the fundamental and spinor representations. These field theories are dual to type IIB string theory compactified on $AdS_5\\times {\\mathbb R} {\\mathbb P}^5$ plus certain choices of discrete torsion, and we use our results to probe this holographic duality. We first revisit the LLM-type geometries having $AdS_5\\times {\\mathbb R} {\\mathbb P}^5$ as ground state. Our results clarify and refine the identification of these LLM-type geometries as bubbling geometries arising from fermions on a half harmonic oscillator. We furthermore identify the presence of discrete torsion with the one-fermion Wigner distribution becoming negative at the origin of phase space. We then turn to the string world-sheet interpretation of our results and argue that for the quantities considered they imply two features: first, the contribution coming from world-sheets with a single crosscap is closely ...

  6. Steerable Doppler transducer probes

    Energy Technology Data Exchange (ETDEWEB)

    Fidel, H.F.; Greenwood, D.L.

    1986-07-22

    An ultrasonic diagnostic probe is described which is capable of performing ultrasonic imaging and Doppler measurement consisting of: a hollow case having an acoustic window which passes ultrasonic energy and including chamber means for containing fluid located within the hollow case and adjacent to a portion of the acoustic window; imaging transducer means, located in the hollow case and outside the fluid chamber means, and oriented to direct ultrasonic energy through the acoustic window toward an area which is to be imaged; Doppler transducer means, located in the hollow case within the fluid chamber means, and movably oriented to direct Doppler signals through the acoustic window toward the imaged area; means located within the fluid chamber means and externally controlled for controllably moving the Doppler transducer means to select one of a plurality of axes in the imaged area along which the Doppler signals are to be directed; and means, located external to the fluid chamber means and responsive to the means for moving, for providing an indication signal for identifying the selected axis.

  7. Transient Astrophysics Probe

    Science.gov (United States)

    Camp, Jordan

    2017-08-01

    Transient Astrophysics Probe (TAP), selected by NASA for a funded Concept Study, is a wide-field high-energy transient mission proposed for flight starting in the late 2020s. TAP’s main science goals, called out as Frontier Discovery areas in the 2010 Decadal Survey, are time-domain astrophysics and counterparts of gravitational wave (GW) detections. The mission instruments include unique imaging soft X-ray optics that allow ~500 deg2 FoV in each of four separate modules; a high sensitivity, 1 deg2 FoV soft X-ray telescope based on single crystal silicon optics; a passively cooled, 1 deg2 FoV Infrared telescope with bandpass 0.6-3 micron; and a set of ~8 small NaI gamma-ray detectors. TAP will observe many events per year of X-ray transients related to compact objects, including tidal disruptions of stars, supernova shock breakouts, neutron star bursts and superbursts, and high redshift Gamma-Ray Bursts. Perhaps most exciting is TAP’s capability to observe X-ray and IR counterparts of GWs involving stellar mass black holes detected by LIGO/Virgo, and possibly X-ray counterparts of GWs from supermassive black holes, detected by LISA and Pulsar Timing Arrays.

  8. Generic entry, reformulations and promotion of SSRIs in the US.

    Science.gov (United States)

    Huskamp, Haiden A; Donohue, Julie M; Koss, Catherine; Berndt, Ernst R; Frank, Richard G

    2008-01-01

    Previous research has shown that a manufacturer's promotional strategy for a brand name drug is typically affected by generic entry. However, little is known about how newer strategies to extend patent life, including product reformulation introduction or obtaining approval to market for additional clinical indications, influence promotion. To examine the relationships among promotional expenditures, generic entry, reformulation entry and new indication approval. We used quarterly data on national product-level promotional spending (including expenditures for physician detailing and direct-to-consumer advertising [DTCA], and the retail value of free samples distributed in physician offices) for selective serotonin reuptake inhibitors (SSRIs) over the period 1997-2004. We estimated econometric models of detailing, DTCA and total quarterly promotional expenditures as a function of the timing of generic entry, entry of new product formulations and US FDA approval for new clinical indications for existing medications in the SSRI class. Expenditures by pharmaceutical manufacturers for promotion of antidepressant medications was the main outcome measure. Over the period 1997-2004, there was considerable variation in the composition of promotional expenditures across the SSRIs. Promotional expenditures for the original brand molecule decreased dramatically when a reformulation of the molecule was introduced. Promotional spending (both total and detailing alone) for a specific molecule was generally lower after generic entry than before, although the effect of generic entry on promotional spending appears to be closely linked with the choice of product reformulation strategy pursued by the manufacturer. Detailing expenditures for Paxil were increased after the manufacturer received FDA approval to market the drug for generalized anxiety disorder (GAD), while the likelihood of DTCA outlays for the drug was not changed. In contrast, FDA approval to market Paxil and Zoloft

  9. Virus entry. Lassa virus entry requires a trigger-induced receptor switch.

    Science.gov (United States)

    Jae, Lucas T; Raaben, Matthijs; Herbert, Andrew S; Kuehne, Ana I; Wirchnianski, Ariel S; Soh, Timothy K; Stubbs, Sarah H; Janssen, Hans; Damme, Markus; Saftig, Paul; Whelan, Sean P; Dye, John M; Brummelkamp, Thijn R

    2014-06-27

    Lassa virus spreads from a rodent to humans and can lead to lethal hemorrhagic fever. Despite its broad tropism, chicken cells were reported 30 years ago to resist infection. We found that Lassa virus readily engaged its cell-surface receptor α-dystroglycan in avian cells, but virus entry in susceptible species involved a pH-dependent switch to an intracellular receptor, the lysosome-resident protein LAMP1. Iterative haploid screens revealed that the sialyltransferase ST3GAL4 was required for the interaction of the virus glycoprotein with LAMP1. A single glycosylated residue in LAMP1, present in susceptible species but absent in birds, was essential for interaction with the Lassa virus envelope protein and subsequent infection. The resistance of Lamp1-deficient mice to Lassa virus highlights the relevance of this receptor switch in vivo.

  10. Quality of data entry using single entry, double entry and automated forms processing--an example based on a study of patient-reported outcomes

    DEFF Research Database (Denmark)

    Paulsen, Aksel; Overgaard, Søren; Lauritsen, Jens Martin

    2012-01-01

    The clinical and scientific usage of patient-reported outcome measures is increasing in the health services. Often paper forms are used. Manual double entry of data is defined as the definitive gold standard for transferring data to an electronic format, but the process is laborious. Automated...

  11. Neural stem cell-derived exosomes mediate viral entry

    Directory of Open Access Journals (Sweden)

    Sims B

    2014-10-01

    Full Text Available Brian Sims,1,2,* Linlin Gu,3,* Alexandre Krendelchtchikov,3 Qiana L Matthews3,4 1Division of Neonatology, Department of Pediatrics, 2Department of Cell, Developmental, and Integrative Biology, 3Division of Infectious Diseases, Department of Medicine, 4Center for AIDS Research, University of Alabama at Birmingham, Birmingham, AL, USA *These authors contributed equally to this work Background: Viruses enter host cells through interactions of viral ligands with cellular receptors. Viruses can also enter cells in a receptor-independent fashion. Mechanisms regarding the receptor-independent viral entry into cells have not been fully elucidated. Exosomal trafficking between cells may offer a mechanism by which viruses can enter cells.Methods: To investigate the role of exosomes on cellular viral entry, we employed neural stem cell-derived exosomes and adenovirus type 5 (Ad5 for the proof-of-principle study. Results: Exosomes significantly enhanced Ad5 entry in Coxsackie virus and adenovirus receptor (CAR-deficient cells, in which Ad5 only had very limited entry. The exosomes were shown to contain T-cell immunoglobulin mucin protein 4 (TIM-4, which binds phosphatidylserine. Treatment with anti-TIM-4 antibody significantly blocked the exosome-mediated Ad5 entry.Conclusion: Neural stem cell-derived exosomes mediated significant cellular entry of Ad5 in a receptor-independent fashion. This mediation may be hampered by an antibody specifically targeting TIM-4 on exosomes. This set of results will benefit further elucidation of virus/exosome pathways, which would contribute to reducing natural viral infection by developing therapeutic agents or vaccines. Keywords: neural stem cell-derived exosomes, adenovirus type 5, TIM-4, viral entry, phospholipids

  12. Improving laboratory data entry quality using Six Sigma.

    Science.gov (United States)

    Elbireer, Ali; Le Chasseur, Julie; Jackson, Brooks

    2013-01-01

    The Uganda Makerere University provides clinical laboratory support to over 70 clients in Uganda. With increased volume, manual data entry errors have steadily increased, prompting laboratory managers to employ the Six Sigma method to evaluate and reduce their problems. The purpose of this paper is to describe how laboratory data entry quality was improved by using Six Sigma. The Six Sigma Quality Improvement (QI) project team followed a sequence of steps, starting with defining project goals, measuring data entry errors to assess current performance, analyzing data and determining data-entry error root causes. Finally the team implemented changes and control measures to address the root causes and to maintain improvements. Establishing the Six Sigma project required considerable resources and maintaining the gains requires additional personnel time and dedicated resources. After initiating the Six Sigma project, there was a 60.5 percent reduction in data entry errors from 423 errors a month (i.e. 4.34 Six Sigma) in the first month, down to an average 166 errors/month (i.e. 4.65 Six Sigma) over 12 months. The team estimated the average cost of identifying and fixing a data entry error to be $16.25 per error. Thus, reducing errors by an average of 257 errors per month over one year has saved the laboratory an estimated $50,115 a year. The Six Sigma QI project provides a replicable framework for Ugandan laboratory staff and other resource-limited organizations to promote quality environment. Laboratory staff can deliver excellent care at a lower cost, by applying QI principles. This innovative QI method of reducing data entry errors in medical laboratories may improve the clinical workflow processes and make cost savings across the health care continuum.

  13. 14 CFR 121.709 - Airworthiness release or aircraft log entry.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airworthiness release or aircraft log entry... Airworthiness release or aircraft log entry. (a) No certificate holder may operate an aircraft after maintenance... appropriate entry in the aircraft log. (b) The airworthiness release or log entry required by paragraph (a)...

  14. A subcutaneous Raman needle probe.

    Science.gov (United States)

    Day, John C C; Stone, Nicholas

    2013-03-01

    Raman spectroscopy is a powerful tool for studying the biochemical composition of tissues and cells in the human body. We describe the initial results of a feasibility study to design and build a miniature, fiber optic probe incorporated into a standard hypodermic needle. This probe is intended for use in optical biopsies of solid tissues to provide valuable information of disease type, such as in the lymphatic system, breast, or prostate, or of such tissue types as muscle, fat, or spinal, when identifying a critical injection site. The optical design and fabrication of this probe is described, and example spectra of various ex vivo samples are shown.

  15. Subminiature Hot-Wire Probes

    Science.gov (United States)

    Westphal, R. V.; Lemos, F. R.; Ligrani, P. M.

    1989-01-01

    Class of improved subminiature hot-wire flow-measuring probes developed. Smaller sizes yield improved resolution in measurements of practical aerodynamic flows. Probe made in one-wire, two-perpendicular-wire, and three-perpendicular-wire version for measurement of one, two, or all three components of flow. Oriented and positioned on micromanipulator stage and viewed under microscope during fabrication. Tested by taking measurements in constant-pressure turbulent boundary layer. New probes give improved measurements of turbulence quantities near surfaces and anisotropies of flows strongly influence relative errors caused by phenomena related to spatial resolution.

  16. Optic probe for semiconductor characterization

    Science.gov (United States)

    Sopori, Bhushan L.; Hambarian, Artak

    2008-09-02

    Described herein is an optical probe (120) for use in characterizing surface defects in wafers, such as semiconductor wafers. The optical probe (120) detects laser light reflected from the surface (124) of the wafer (106) within various ranges of angles. Characteristics of defects in the surface (124) of the wafer (106) are determined based on the amount of reflected laser light detected in each of the ranges of angles. Additionally, a wafer characterization system (100) is described that includes the described optical probe (120).

  17. Flight characteristics of probes in the atmospheres of Mars, Venus, and the outer planets

    Science.gov (United States)

    Intrieri, P. F.; Derose, C. E.; Kirk, D. B.

    1976-01-01

    Density, pressure, and temperature profiles of an unknown planetary atmosphere can be obtained from the high-speed entry of a probe provided the aerodynamic characteristics of the probe in this atmosphere are accurately known. An investigation of the effect of gas composition on probe aerodynamics has been conducted in the Ames Hypersonic Free Flight Facility by gun launching small-scale models into atmospheres representative of Mars, Venus, Jupiter, and Saturn. Aerodynamic data at conditions matching the velocity and Reynolds number at a number of points on the Viking trajectory (Mars) were obtained in both air and carbon dioxide and significant differences were noted. Aerodynamic data are also presented from tests in hydrogen and hydrogen-helium mixtures, gases which characterize the atmospheres of the outer planets.

  18. Caveolin-1 associated adenovirus entry into human corneal cells.

    Directory of Open Access Journals (Sweden)

    Mohammad A Yousuf

    Full Text Available The cellular entry of viruses represents a critical area of study, not only for viral tropism, but also because viral entry dictates the nature of the immune response elicited upon infection. Epidemic keratoconjunctivitis (EKC, caused by viruses within human adenovirus species D (HAdV-D, is a severe, ocular surface infection associated with corneal inflammation. Clathrin-mediated endocytosis has previously been shown to play a critical role in entry of other HAdV species into many host cell types. However, HAdV-D endocytosis into corneal cells has not been extensively studied. Herein, we show an essential role for cholesterol rich, lipid raft microdomains and caveolin-1, in the entry of HAdV-D37 into primary human corneal fibroblasts. Cholesterol depletion using methyl-β-cyclodextrin (MβCD profoundly reduced viral infection. When replenished with soluble cholesterol, the effect of MβCD was reversed, allowing productive viral infection. HAdV-D37 DNA was identified in caveolin-1 rich endosomal fractions after infection. Src kinase activity was also increased in caveolin-1 rich endosomal fractions after infection, and Src phosphorylation and CXCL1 induction were both decreased in caveolin-1-/- mice corneas compared to wild type mice. siRNA knock down of caveolin-1 in corneal cells reduced chemokine induction upon viral infection, and caveolin-1-/- mouse corneas showed reduced cellular entry of HAdV-D37. As a control, HAdV-C2, a non-corneal pathogen, appeared to utilize the caveolar pathway for entry into A549 cells, but failed to infect corneal cells entirely, indicating virus and cell specific tropism. Immuno-electron microscopy confirmed the presence of caveolin-1 in HAdV-D37-containing vesicles during the earliest stages of viral entry. Collectively, these experiments indicate for the first time that HAdV-D37 uses a lipid raft mediated caveolin-1 associated pathway for entry into corneal cells, and connects the processes of viral entry with

  19. Advanced entry guidance algorithm with landing footprint computation

    Science.gov (United States)

    Leavitt, James Aaron

    The design and performance evaluation of an entry guidance algorithm for future space transportation vehicles is presented. The algorithm performs two functions: on-board trajectory planning and trajectory tracking. The planned longitudinal path is followed by tracking drag acceleration, as is done by the Space Shuttle entry guidance. Unlike the Shuttle entry guidance, lateral path curvature is also planned and followed. A new trajectory planning function for the guidance algorithm is developed that is suitable for suborbital entry and that significantly enhances the overall performance of the algorithm for both orbital and suborbital entry. In comparison with the previous trajectory planner, the new planner produces trajectories that are easier to track, especially near the upper and lower drag boundaries and for suborbital entry. The new planner accomplishes this by matching the vehicle's initial flight path angle and bank angle, and by enforcing the full three-degree-of-freedom equations of motion with control derivative limits. Insights gained from trajectory optimization results contribute to the design of the new planner, giving it near-optimal downrange and crossrange capabilities. Planned trajectories and guidance simulation results are presented that demonstrate the improved performance. Based on the new planner, a method is developed for approximating the landing footprint for entry vehicles in near real-time, as would be needed for an on-board flight management system. The boundary of the footprint is constructed from the endpoints of extreme downrange and crossrange trajectories generated by the new trajectory planner. The footprint algorithm inherently possesses many of the qualities of the new planner, including quick execution, the ability to accurately approximate the vehicle's glide capabilities, and applicability to a wide range of entry conditions. Footprints can be generated for orbital and suborbital entry conditions using a pre

  20. Dopamine Receptor Activation Increases HIV Entry into Primary Human Macrophages

    Science.gov (United States)

    Gaskill, Peter J.; Yano, Hideaki H.; Kalpana, Ganjam V.; Javitch, Jonathan A.; Berman, Joan W.

    2014-01-01

    Macrophages are the primary cell type infected with HIV in the central nervous system, and infection of these cells is a major component in the development of neuropathogenesis and HIV-associated neurocognitive disorders. Within the brains of drug abusers, macrophages are exposed to increased levels of dopamine, a neurotransmitter that mediates the addictive and reinforcing effects of drugs of abuse such as cocaine and methamphetamine. In this study we examined the effects of dopamine on HIV entry into primary human macrophages. Exposure to dopamine during infection increased the entry of R5 tropic HIV into macrophages, irrespective of the concentration of the viral inoculum. The entry pathway affected was CCR5 dependent, as antagonizing CCR5 with the small molecule inhibitor TAK779 completely blocked entry. The effect was dose-dependent and had a steep threshold, only occurring above 108 M dopamine. The dopamine-mediated increase in entry required dopamine receptor activation, as it was abrogated by the pan-dopamine receptor antagonist flupenthixol, and could be mediated through both subtypes of dopamine receptors. These findings indicate that the effects of dopamine on macrophages may have a significant impact on HIV pathogenesis. They also suggest that drug-induced increases in CNS dopamine may be a common mechanism by which drugs of abuse with distinct modes of action exacerbate neuroinflammation and contribute to HIV-associated neurocognitive disorders in infected drug abusers. PMID:25268786

  1. Dopamine receptor activation increases HIV entry into primary human macrophages.

    Directory of Open Access Journals (Sweden)

    Peter J Gaskill

    Full Text Available Macrophages are the primary cell type infected with HIV in the central nervous system, and infection of these cells is a major component in the development of neuropathogenesis and HIV-associated neurocognitive disorders. Within the brains of drug abusers, macrophages are exposed to increased levels of dopamine, a neurotransmitter that mediates the addictive and reinforcing effects of drugs of abuse such as cocaine and methamphetamine. In this study we examined the effects of dopamine on HIV entry into primary human macrophages. Exposure to dopamine during infection increased the entry of R5 tropic HIV into macrophages, irrespective of the concentration of the viral inoculum. The entry pathway affected was CCR5 dependent, as antagonizing CCR5 with the small molecule inhibitor TAK779 completely blocked entry. The effect was dose-dependent and had a steep threshold, only occurring above 108 M dopamine. The dopamine-mediated increase in entry required dopamine receptor activation, as it was abrogated by the pan-dopamine receptor antagonist flupenthixol, and could be mediated through both subtypes of dopamine receptors. These findings indicate that the effects of dopamine on macrophages may have a significant impact on HIV pathogenesis. They also suggest that drug-induced increases in CNS dopamine may be a common mechanism by which drugs of abuse with distinct modes of action exacerbate neuroinflammation and contribute to HIV-associated neurocognitive disorders in infected drug abusers.

  2. A Novel Keyless Entry System Using Visible Light Communication

    Directory of Open Access Journals (Sweden)

    Kuniyoshi Okuda

    2014-10-01

    Full Text Available A major conventional car key is the mechanical key. When users inserted the key into a cylinder mechanical key and turn, users can unlock. The mechanical key may be able to be worn away for physical contact. And it may be impossible to use. Further the mechanical key may be damaged or destroyed by mischief. So a keyless entry system has been developed. The keyless entry system locks and unlocks using the infrared ray and radio waves communication. The keyless entry system does not require physical contacts. Therefore, the possibilities of damage due to mischief and be worn away are fell. However, the transmission ranges of infrared ray and radio waves communication are not clear. Submitting data might be tapped to the malicious people. If the information is tapped, then you have theft of the car and the risk of car break. We propose a keyless entry system using visible light communication in order to solve this problem. Visible light communication transmits signal using blinking light. Thus the transmission range is clear. The user can transmit the information only to the aimed place. Therefore, the usability is improved. We measure the durations of "take out the remote control", "put the aim" and "takes to unlock key" in order to evaluate the usability in the experiment. We also compared with the infrared ray communication and examined the superiority. Usability is improved in the experimental results, and usability is better than conventional keyless entry system.

  3. Structural and mechanistic studies of measles virus illuminate paramyxovirus entry.

    Directory of Open Access Journals (Sweden)

    Richard K Plemper

    2011-06-01

    Full Text Available Measles virus (MeV, a member of the paramyxovirus family of enveloped RNA viruses and one of the most infectious viral pathogens identified, accounts for major pediatric morbidity and mortality worldwide although coordinated efforts to achieve global measles control are in place. Target cell entry is mediated by two viral envelope glycoproteins, the attachment (H and fusion (F proteins, which form a complex that achieves merger of the envelope with target cell membranes. Despite continually expanding knowledge of the entry strategies employed by enveloped viruses, our molecular insight into the organization of functional paramyxovirus fusion complexes and the mechanisms by which the receptor binding by the attachment protein triggers the required conformational rearrangements of the fusion protein remain incomplete. Recently reported crystal structures of the MeV attachment protein in complex with its cellular receptors CD46 or SLAM and newly developed functional assays have now illuminated some of the fundamental principles that govern cell entry by this archetype member of the paramyxovirus family. Here, we review these advances in our molecular understanding of MeV entry in the context of diverse entry strategies employed by other members of the paramyxovirus family.

  4. A Gestalt approach to Gram-negative entry.

    Science.gov (United States)

    Silver, Lynn L

    2016-12-15

    A major obstacle confronting the discovery and development of new antibacterial agents to combat resistant Gram-negative (GN) organisms is the lack of a rational process for endowing compounds with properties that allow (or promote) entry into the bacterial cytoplasm. The major permeability difference between GN and Gram-positive (GP) bacteria is the GN outer membrane (OM) which is a permeability barrier itself and potentiates efflux pumps that expel compounds. Based on the fact that OM-permeable and efflux-deleted GNs are sensitive to many anti-GP drugs, recent efforts to approach the GN entry problem have focused on ways of avoiding efflux and transiting or compromising the OM, with the tacit assumption that this could allow entry of compounds into the GN cytoplasm. But bypassing the OM and efflux obstacles does not take into account the additional requirement of penetrating the cytoplasmic membrane (CM) whose sieving properties appear to be orthogonal to that of the OM. That is, tailoring compounds to transit the OM may well compromise their ability to enter the cytoplasm. Thus, a Gestalt approach to understanding the chemical requirements for GN entry seems a useful adjunct. This might consist of characterizing compounds which reach the cytoplasm, grouping (or binning) by routes of entry and formulating chemical 'rules' for those bins. This will require acquisition of data on large numbers of compounds, using non-activity-dependent methods of measuring accumulation in the cytoplasm. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Trading Robustness Requirements in Mars Entry Trajectory Design

    Science.gov (United States)

    Lafleur, Jarret M.

    2009-01-01

    One of the most important metrics characterizing an atmospheric entry trajectory in preliminary design is the size of its predicted landing ellipse. Often, requirements for this ellipse are set early in design and significantly influence both the expected scientific return from a particular mission and the cost of development. Requirements typically specify a certain probability level (6-level) for the prescribed ellipse, and frequently this latter requirement is taken at 36. However, searches for the justification of 36 as a robustness requirement suggest it is an empirical rule of thumb borrowed from non-aerospace fields. This paper presents an investigation into the sensitivity of trajectory performance to varying robustness (6-level) requirements. The treatment of robustness as a distinct objective is discussed, and an analysis framework is presented involving the manipulation of design variables to effect trades between performance and robustness objectives. The scenario for which this method is illustrated is the ballistic entry of an MSL-class Mars entry vehicle. Here, the design variable is entry flight path angle, and objectives are parachute deploy altitude performance and error ellipse robustness. Resulting plots show the sensitivities between these objectives and trends in the entry flight path angles required to design to these objectives. Relevance to the trajectory designer is discussed, as are potential steps for further development and use of this type of analysis.

  6. BST2/Tetherin enhances entry of human cytomegalovirus.

    Directory of Open Access Journals (Sweden)

    Kasinath Viswanathan

    2011-11-01

    Full Text Available Interferon-induced BST2/Tetherin prevents budding of vpu-deficient HIV-1 by tethering mature viral particles to the plasma membrane. BST2 also inhibits release of other enveloped viruses including Ebola virus and Kaposi's sarcoma associated herpesvirus (KSHV, indicating that BST2 is a broadly acting antiviral host protein. Unexpectedly however, recovery of human cytomegalovirus (HCMV from supernatants of BST2-expressing human fibroblasts was increased rather than decreased. Furthermore, BST2 seemed to enhance viral entry into cells since more virion proteins were released into BST2-expressing cells and subsequent viral gene expression was elevated. A significant increase in viral entry was also observed upon induction of endogenous BST2 during differentiation of the pro-monocytic cell line THP-1. Moreover, treatment of primary human monocytes with siRNA to BST2 reduced HCMV infection, suggesting that BST2 facilitates entry of HCMV into cells expressing high levels of BST2 either constitutively or in response to exogenous stimuli. Since BST2 is present in HCMV particles we propose that HCMV entry is enhanced via a reverse-tethering mechanism with BST2 in the viral envelope interacting with BST2 in the target cell membrane. Our data suggest that HCMV not only counteracts the well-established function of BST2 as inhibitor of viral egress but also employs this anti-viral protein to gain entry into BST2-expressing hematopoietic cells, a process that might play a role in hematogenous dissemination of HCMV.

  7. Rhadinovirus host entry by co-operative infection.

    Directory of Open Access Journals (Sweden)

    Clara Lawler

    2015-03-01

    Full Text Available Rhadinoviruses establish chronic infections of clinical and economic importance. Several show respiratory transmission and cause lung pathologies. We used Murid Herpesvirus-4 (MuHV-4 to understand how rhadinovirus lung infection might work. A primary epithelial or B cell infection often is assumed. MuHV-4 targeted instead alveolar macrophages, and their depletion reduced markedly host entry. While host entry was efficient, alveolar macrophages lacked heparan - an important rhadinovirus binding target - and were infected poorly ex vivo. In situ analysis revealed that virions bound initially not to macrophages but to heparan⁺ type 1 alveolar epithelial cells (AECs. Although epithelial cell lines endocytose MuHV-4 readily in vitro, AECs did not. Rather bound virions were acquired by macrophages; epithelial infection occurred only later. Thus, host entry was co-operative - virion binding to epithelial cells licensed macrophage infection, and this in turn licensed AEC infection. An antibody block of epithelial cell binding failed to block host entry: opsonization provided merely another route to macrophages. By contrast an antibody block of membrane fusion was effective. Therefore co-operative infection extended viral tropism beyond the normal paradigm of a target cell infected readily in vitro; and macrophage involvement in host entry required neutralization to act down-stream of cell binding.

  8. Small Probe Reentry System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Aerospace Corporation (GAC), and its research partner, Cal Poly San Luis Obispo (CPSLO), will develop an integrated Small Probe Reentry System (SPRS) for low...

  9. Lunar Probe Reaches Deep Space

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ China's second lunar probe, Chang'e-2, has reached an orbit 1.5 million kilometers from Earth for an additional mission of deep space exploration, the State Administration for Science, Technology and Industry for National Defense announced.

  10. DNA probe for lactobacillus delbrueckii

    Energy Technology Data Exchange (ETDEWEB)

    Delley, M.; Mollet, B.; Hottinger, H. (Nestle Research Centre, Lausanne (Switzerland))

    1990-06-01

    From a genomic DNA library of Lactobacillus delbrueckii subsp. bulgaricus, a clone was isolated which complements a leucine auxotrophy of an Escherichia coli strain (GE891). Subsequent analysis of the clone indicated that it could serve as a specific DNA probe. Dot-blot hybridizations with over 40 different Lactobacillus strains showed that this clone specifically recognized L. delbrueckii subsp. delbrueckii, bulgaricus, and lactis. The sensitivity of the method was tested by using an {alpha}-{sup 32}P-labeled probe.

  11. Transformer-coupled NMR probe

    Science.gov (United States)

    Utsuzawa, Shin; Mandal, Soumyajit; Song, Yi-Qiao

    2012-03-01

    In this study, we propose an NMR probe circuit that uses a transformer with a ferromagnetic core for impedance matching. The ferromagnetic core provides a strong but confined coupling that result in efficient energy transfer between the sample coil and NMR spectrometer, while not disturbing the B1 field generated by the sample coil. We built a transformer-coupled NMR probe and found that it offers comparable performance (loss NQR.

  12. Info-tsunami: surviving the storm with data quality probes

    Directory of Open Access Journals (Sweden)

    Philip Brown

    2003-12-01

    Full Text Available As a result of the rapid expansion of electronically available clinical knowledge, clinicians are faced with potential information overload (info-tsunami. The use of data quality probes (DQPs in primary care can encourage clinicians' awareness of, and improvement in, data quality entry over time. DQPs can also highlight areas of potential error or omission as well as good practice, which can impact directly upon the quality of patient care. In this paper, five specific conditions have been subjected to the use of a series of DQPs over a five-year period in order to assess and measure the performance of different initiatives on the quality of data capture and patient care.

  13. Probing physics students' conceptual knowledge structures through term association

    CERN Document Server

    Beatty, I D; Beatty, Ian D.; Gerace, William J.

    2002-01-01

    Traditional tests are not effective tools for diagnosing the content and structure of students' knowledge of physics. As a possible alternative, a set of term-association tasks (the "ConMap" tasks) was developed to probe the interconnections within students' store of conceptual knowledge. The tasks have students respond spontaneously to a term or problem or topic area with a sequence of associated terms; the response terms and timeof- entry data are captured. The tasks were tried on introductory physics students, and preliminary investigations show that the tasks are capable of eliciting information about the stucture of their knowledge. Specifically, data gathered through the tasks is similar to that produced by a hand-drawn concept map task, has measures that correlate with inclass exam performance, and is sensitive to learning produced by topic coverage in class. Although the results are preliminary and only suggestive, the tasks warrant further study as student-knowledge assessment instruments and sources...

  14. Space Shuttle Orbiter entry guidance and control system sensitivity analysis

    Science.gov (United States)

    Stone, H. W.; Powell, R. W.

    1976-01-01

    An approach has been developed to determine the guidance and control system sensitivity to off-nominal aerodynamics for the Space Shuttle Orbiter during entry. This approach, which uses a nonlinear six-degree-of-freedom interactive, digital simulation, has been applied to both the longitudinal and lateral-directional axes for a portion of the orbiter entry. Boundary values for each of the aerodynamic parameters have been identified, the key parameters have been determined, and system modifications that will increase system tolerance to off-nominal aerodynamics have been recommended. The simulations were judged by specified criteria and the performance was evaluated by use of key dependent variables. The analysis is now being expanded to include the latest shuttle guidance and control systems throughout the entry speed range.

  15. Shuttle entry guidance revisited using nonlinear geometric methods

    Science.gov (United States)

    Mease, Kenneth D.; Kremer, Jean-Paul

    1994-11-01

    The entry guidance law for the space shuttle orbiter is revisited using nonlinear geometric methods. The shuttle guidance concept is to track a reference drag trajectory that has been designed to lead a specified range and velocity. It is shown that the approach taken in the original derivation of the shuttle entry guidance has much in common with the more recently developed feedback linearization method of differential geometric control. Using the feedback linearization method, however, an alternative, potentially superior, guidance law was formulated. Comparing the two guidance laws based performance domains in state space, taking into account the nonlinear dynamics, the alternative guidance law achieves the desired performance over larger domains in state space; the stability domain of the laws are similar. With larger operating domain for the shuttle or some other entry vehicle, the alternative guidance law should be considered.

  16. Confined space entry program for the Westinghouse Hanford Company

    Energy Technology Data Exchange (ETDEWEB)

    Cornell, T.M.

    1993-11-01

    To comply with anticipated OSHA regulatory requirements concerning Permit-Required Confined Spaces, Westinghouse Hanford Company (WHC) created a Confined Spaces Task Team. The primary focus of the task team was to prepare a formal Confined Space Entry (CSE) Program that would ensure full compliance with the anticipated OSHA requirements. A comprehensive training plan was also prepared and submitted for approval as soon as the new CSE Program was approved and released for implementation. On January 14, 1993, OSHA released their final ruling which contained several further changes, requiring the WHC Confined Space Entry Program and Training Plan to be revised. The revised training manual and lessons learned in establishing a Confined Space Entry Program are presented.

  17. Pesticides re-entry dermal exposure of workers in greenhouses.

    Science.gov (United States)

    Caffarelli, V; Conte, E; Correnti, A; Gatti, R; Musmeci, F; Morali, G; Spagnoli, G; Tranfo, G; Triolo, L; Vita, M; Zappa, G

    2004-01-01

    This research has the aim to evaluate the risk of pesticide dermal exposure for workers in greenhouses. We considered the following crops: tomato, cucumber and strawberry, largely spread in Bracciano lake district. The pesticides monitored were: tetradifon on strawberry: metalaxyl, azoxystrobin and fenarimol on cucumber; acrinathrin, azoxystrobin and chlorpyrifos ethyl on tomato. The dermal exposure was evaluated by Dislodgeable Foliar Residue (DFR) measurements employing transfer coefficients got from literature. For risk evaluation, we have compared the dermal exposures with Acceptable Operator Exposure Levels (AOEL). The re-entry time were obtained intercepting the dose decay curves with AOEL values. The re-entry times result higher than two days in the cases of chlorpyrifos on tomato (re-entry time: 3 days), azoxystrobin on tomato (4 days), and tetradifon on strawberry (8 days). The need of measuring specific transfer coefficients is pointed out.

  18. Mars Entry Atmospheric Data System Modeling, Calibration, and Error Analysis

    Science.gov (United States)

    Karlgaard, Christopher D.; VanNorman, John; Siemers, Paul M.; Schoenenberger, Mark; Munk, Michelle M.

    2014-01-01

    The Mars Science Laboratory (MSL) Entry, Descent, and Landing Instrumentation (MEDLI)/Mars Entry Atmospheric Data System (MEADS) project installed seven pressure ports through the MSL Phenolic Impregnated Carbon Ablator (PICA) heatshield to measure heatshield surface pressures during entry. These measured surface pressures are used to generate estimates of atmospheric quantities based on modeled surface pressure distributions. In particular, the quantities to be estimated from the MEADS pressure measurements include the dynamic pressure, angle of attack, and angle of sideslip. This report describes the calibration of the pressure transducers utilized to reconstruct the atmospheric data and associated uncertainty models, pressure modeling and uncertainty analysis, and system performance results. The results indicate that the MEADS pressure measurement system hardware meets the project requirements.

  19. Tannin inhibits HIV-1 entry by targeting gp41

    Institute of Scientific and Technical Information of China (English)

    Lin L(U); Shu-wen LIU; Shi-bo JIANG; Shu-guang WU

    2004-01-01

    AIM: To investigate the mechanism by which tannin inhibits HIV-1 entry into target cells. METHODS: The inhibitory activity of tannin on HIV-1 replication and entry was detected by p24 production and HIV-1-mediated cell fusion, respectively. The inhibitory activity on the gp41 six-helix bundle formation was determined by an improved sandwich ELISA. RESULTS: Tannins from different sources showed potent inhibitory activity on HIV-1 replication,HIV-1-mediated cell fusion, and the gp4 six-helix bundle formation. CONCLUSION: Tannin inhibits HIV-1 entry into target cells by interfering with the gp41 six-helix bundle formation, thus blocking HIV-1 fusion with the target cell.

  20. Towards a Market Entry Framework for Digital Payment Platforms

    DEFF Research Database (Denmark)

    Kazan, Erol; Damsgaard, Jan

    2016-01-01

    This study presents a framework to understand and explain the design and configuration of digital payment platforms and how these platforms create conditions for market entries. By embracing the theoretical lens of platform envelopment, we employed a multiple and comparative-case study...... in a European setting by using our framework as an analytical lens to assess market-entry conditions. We found that digital payment platforms have acquired market entry capabilities, which is achieved through strategic platform design (i.e., platform development and service distribution) and technology design...... (i.e., issuing evolutionary and revolutionary payment instruments). The studied cases reveal that digital platforms leverage payment services as a mean to bridge and converge core and adjacent platform markets. In so doing, platform envelopment strengthens firms’ market position in their respective...

  1. Mars Atmospheric Entry Integrated Navigation with Partial Intermittent Measurements

    Directory of Open Access Journals (Sweden)

    Tai-shan Lou

    2017-01-01

    Full Text Available Signal degradation suffered by the vehicle is a combination brownout and blackout during Mars atmospheric entry. The communications brownout means that signal fades and blackout means that the signal is lost completely. The communications brownout and blackout periods are analyzed and predicted with an altitude and velocity profiles. In the brownout period, the range measurements between the vehicle and the orbiters are modeled as intermittent measurements with the radio signal arrival probabilities, which are distributed as a Rayleigh distribution of the electron number density around the entry vehicle. A new integrated navigation strategy during the Mars atmospheric entry phase is proposed to consider the probabilities of the radio measurements in the communications brownout and blackout periods under the IMU/beacon scenario based on the information filter with intermittent measurements. Numerical navigation simulations are designed to show the performance of the proposed navigation strategy under the integrated navigation scenario.

  2. Towards a Market Entry Framework for Digital Payment Platforms

    DEFF Research Database (Denmark)

    Kazan, Erol; Damsgaard, Jan

    2016-01-01

    (i.e., issuing evolutionary and revolutionary payment instruments). The studied cases reveal that digital platforms leverage payment services as a mean to bridge and converge core and adjacent platform markets. In so doing, platform envelopment strengthens firms’ market position in their respective......This study presents a framework to understand and explain the design and configuration of digital payment platforms and how these platforms create conditions for market entries. By embracing the theoretical lens of platform envelopment, we employed a multiple and comparative-case study...... in a European setting by using our framework as an analytical lens to assess market-entry conditions. We found that digital payment platforms have acquired market entry capabilities, which is achieved through strategic platform design (i.e., platform development and service distribution) and technology design...

  3. Disambiguating bilingual nominal entries against WordNet

    CERN Document Server

    Rigau, G; Rigau, German; Agirre, Eneko

    1995-01-01

    This paper explores the acquisition of conceptual knowledge from bilingual dictionaries (French/English, Spanish/English and English/Spanish) using a pre-existing broad coverage Lexical Knowledge Base (LKB) WordNet. Bilingual nominal entries are disambiguated agains WordNet, therefore linking the bilingual dictionaries to WordNet yielding a multilingual LKB (MLKB). The resulting MLKB has the same structure as WordNet, but some nodes are attached additionally to disambiguated vocabulary of other languages. Two different, complementary approaches are explored. In one of the approaches each entry of the dictionary is taken in turn, exploiting the information in the entry itself. The inferential capability for disambiguating the translation is given by Semantic Density over WordNet. In the other approach, the bilingual dictionary was merged with WordNet, exploiting mainly synonymy relations. Each of the approaches was used in a different dictionary. Both approaches attain high levels of precision on their own, sh...

  4. Nonequilibrium radiative heating of a Jovian entry body

    Science.gov (United States)

    Tiwari, S. N.; Subramanian, S. V.

    1979-01-01

    The influence of nonlocal thermodynamic equilibrium (NLTE) radiative transfer on radiative and convective heating of a Jovian entry body is investigated. The flow in the shock layer is assumed to be axisymmetric, viscous, and in chemical equilibrium. The chemical species considered for the collisional deactivation processes are H2, H, H+. The NLTE radiative transfer equations are derived for multilevel energy transitions. The rotational and vibrational energy modes are assumed to be in local thermodynamic equilibrium. The results indicate that higher-level energy transitions have little influence on the overall NLTE results. The NLTE results, however, are found to be greatly influenced by the temperature distributions in the shock layer. The convective and radiative heating to the entry body are reduced significantly because of the NLTE conditions; the reduction in convective heating, however, is relatively small. The influence of NLTE is found to be greater at higher entry altitudes.

  5. HIV entry inhibitors: a new generation of antiretroviral drugs

    Institute of Scientific and Technical Information of China (English)

    Elias KRAMBOVITIS; Filippos PORICHIS; Demetrios A SPANDIDOS

    2005-01-01

    AIDS is presently treatable, and patients can have a good prognosis due to the success of highly active antiretroviral therapy (HAART), but it is still not curable or preventable. High toxicity of HAART, and the emergence of drug resistance add to the imperative to continue research into new strategies and interventions.Considerable progress in the understanding of HIV attachment and entry into host cells has suggested new possibilities for rationally designing agents that interfere with this process. The approval and introduction of the fusion inhibitor enfuvirtide (Fuzeon) for clinical use signals a new era in AIDS therapeutics. Here we review the crucial steps the virus uses to achieve cell entry, which merit attention as potential targets, and the compounds at pre-clinical and clinical development stages, reported to effectively inhibit cell entry.

  6. Mars Science Laboratory Entry Guidance Improvements for Mars 2018 (DRAFT)

    Science.gov (United States)

    Garcia-Llama, Eduardo; Winski, Richard G.; Shidner, Jeremy D.; Ivanov, Mark C.; Grover, Myron R.; Prakash, Ravi

    2011-01-01

    In 2011, the Mars Science Laboratory (MSL) will be launched in a mission to deliver the largest and most capable rover to date to the surface of Mars. A follow on MSL-derived mission, referred to as Mars 2018, is planned for 2018. Mars 2018 goals include performance enhancements of the Entry, Descent and Landing over that of its predecessor MSL mission of 2011. This paper will discuss the main elements of the modified 2018 EDL preliminary design that will increase performance on the entry phase of the mission. In particular, these elements will increase the parachute deploy altitude to allow for more time margin during the subsequent descent and landing phases and reduce the delivery ellipse size at parachute deploy through modifications in the entry reference trajectory design, guidance trigger logic design, and the effect of additional navigation hardware.

  7. Features of Human Herpesvirus-6A and -6B Entry

    Directory of Open Access Journals (Sweden)

    Takahiro Maeki

    2012-01-01

    Full Text Available Human herpesvirus-6 (HHV-6 is a T lymphotropic herpesvirus belonging to the Betaherpesvirinae subfamily. HHV-6 was long classified into variants A and B (HHV-6A and HHV-6B; however, recently, HHV-6A and HHV-6B were reclassified as different species. The process of herpesvirus entry into target cells is complicated, and in the case of HHV-6A and HHV-6B, the detailed mechanism remains to be elucidated, although both viruses are known to enter cells via endocytosis. In this paper, (1 findings about the cellular receptor and its ligand for HHV-6A and HHV-6B are summarized, and (2 a schematic model of HHV-6A’s replication cycle, including its entry, is presented. In addition, (3 reports showing the importance of lipids in both the HHV-6A envelope and target-cell membrane for viral entry are reviewed, and (4 glycoproteins involved in cell fusion are discussed.

  8. The role of digital data entry in participatory environmental monitoring.

    Science.gov (United States)

    Brammer, Jeremy R; Brunet, Nicolas D; Burton, A Cole; Cuerrier, Alain; Danielsen, Finn; Dewan, Kanwaljeet; Herrmann, Thora Martina; Jackson, Micha V; Kennett, Rod; Larocque, Guillaume; Mulrennan, Monica; Pratihast, Arun Kumar; Saint-Arnaud, Marie; Scott, Colin; Humphries, Murray M

    2016-12-01

    Many argue that monitoring conducted exclusively by scientists is insufficient to address ongoing environmental challenges. One solution entails the use of mobile digital devices in participatory monitoring (PM) programs. But how digital data entry affects programs with varying levels of stakeholder participation, from nonscientists collecting field data to nonscientists administering every step of a monitoring program, remains unclear. We reviewed the successes, in terms of management interventions and sustainability, of 107 monitoring programs described in the literature (hereafter programs) and compared these with case studies from our PM experiences in Australia, Canada, Ethiopia, Ghana, Greenland, and Vietnam (hereafter cases). Our literature review showed that participatory programs were less likely to use digital devices, and 2 of our 3 more participatory cases were also slow to adopt digital data entry. Programs that were participatory and used digital devices were more likely to report management actions, which was consistent with cases in Ethiopia, Greenland, and Australia. Programs engaging volunteers were more frequently reported as ongoing, but those involving digital data entry were less often sustained when data collectors were volunteers. For the Vietnamese and Canadian cases, sustainability was undermined by a mismatch in stakeholder objectives. In the Ghanaian case, complex field protocols diminished monitoring sustainability. Innovative technologies attract interest, but the foundation of effective participatory adaptive monitoring depends more on collaboratively defined questions, objectives, conceptual models, and monitoring approaches. When this foundation is built through effective partnerships, digital data entry can enable the collection of more data of higher quality. Without this foundation, or when implemented ineffectively or unnecessarily, digital data entry can be an additional expense that distracts from core monitoring objectives

  9. Optometry Australia Entry-level Competency Standards for Optometry 2014.

    Science.gov (United States)

    Kiely, Patricia M; Slater, Jared

    2015-01-01

    Competency standards for entry-level to the profession of optometry in Australia were first developed in 1993, revised in 1997 and 2000, and again in 2008, when therapeutic competency standards were introduced but differentiated from the entry-level competencies. Therapeutic competencies were an additional requirement for the purpose of endorsing optometric registration to allow prescription of medicines for conditions of the eye. Recent changes to educational and registration requirements mean that therapeutic competencies are now required at entry-level. To address this and to ensure the standards reflect current best practice, a full revision of the standards was undertaken. A steering committee oversaw the review of the standards, which involved a literature review, workshops with optometrists and broad consultation with stakeholders, including the Optometry Board of Australia, individual optometrists and employers of optometrists, to identify changes needed. Representatives of the profession from Australia and New Zealand and from academia in Australia were involved. A modified document based on the feedback received was circulated to the State Divisions and the National Board of the then Optometrists Association Australia. The updated standards reflect the state of entry to the optometric profession in 2014; competencies for prescribing of scheduled medicines are included, new material has been added, other areas have been modified. The updated entry-level competency standards were adopted on behalf of the profession by the National Board of the then Optometrists Association Australia in March 2014. Competency standards have been updated so that they continue to be current and useful for the profession, individual optometrists and Australian and New Zealand registration authorities for the purposes of accreditation of optometric programs and assessment of overseas-trained optometrists. This paper details the revision process and presents the 2014 version of

  10. Alternative endocytosis pathway for productive entry of hepatitis C virus.

    Science.gov (United States)

    Matsuda, Mami; Suzuki, Ryosuke; Kataoka, Chikako; Watashi, Koichi; Aizaki, Hideki; Kato, Nobuyuki; Matsuura, Yoshiharu; Suzuki, Tetsuro; Wakita, Takaji

    2014-12-01

    Previous studies have shown that hepatitis C virus (HCV) enters human hepatic cells through interaction with a series of cellular receptors, followed by clathrin-mediated, pH-dependent endocytosis. Here, we investigated the mechanisms of HCV entry into multiple HCV-permissive human hepatocyte-derived cells using trans-complemented HCV particles (HCVtcp). Knockdown of CD81 and claudin-1, or treatment with bafilomycin A1, reduced infection in Huh-7 and Huh7.5.1 cells, suggesting that HCV entered both cell types via receptor-mediated, pH-dependent endocytosis. Interestingly, knockdown of the clathrin heavy chain or dynamin-2 (Dyn2), as well as expression of the dominant-negative form of Dyn2, reduced infection of Huh-7 cells with HCVtcp, whereas infectious entry of HCVtcp into Huh7.5.1 cells was not impaired. Infection of Huh7.5.1 cells with culture-derived HCV (HCVcc) via a clathrin-independent pathway was also observed. Knockdown of caveolin-1, ADP-ribosylation factor 6 (Arf6), flotillin, p21-activated kinase 1 (PAK1) and the PAK1 effector C-terminal binding protein 1 of E1A had no inhibitory effects on HCVtcp infection into Huh7.5.1 cells, thus suggesting that the infectious entry pathway of HCV into Huh7.5.1 cells was not caveolae-mediated, or Arf6- and flotillin-mediated endocytosis and macropinocytosis, but rather may have occurred via an undefined endocytic pathway. Further analysis revealed that HCV entry was clathrin- and dynamin-dependent in ORL8c and HepCD81/miR122 cells, but productive entry of HCV was clathrin- and dynamin-independent in Hep3B/miR122 cells. Collectively, these data indicated that HCV entered different target cells through different entry routes.

  11. BeppoSAX equatorial uncontrolled re-entry

    Science.gov (United States)

    Portelli, C.

    The X-ray astronomy satellite BeppoSAX (Satellite per Astronomia X, "Beppo" in honor of Giuseppe Occhialini), is a project of the Italian Space Agency (ASI) with participation of the Netherlands Agency for Aerospace Programs (NIVR). BeppoSAX was launched by an Atlas G Centaur directly into a circular 600 km- orbit at 3.9 degrees inclination on April 30th, 1996. The satellite is a three axis stabilized spacecraft with a total mass of about 1400 kg. The current (May 1, 2002) flight altitude is about 470 km and its uncontrolled re-entry is predicted late in 2002, or in 2003, with a 26 kg of hydrazine on board that could not be vented or used for controlled re-entry due to gyro's package total failure. Due to the relatively high mass of BeppoSAX, it has to be expected that parts of the satellite will survive the re-entry into the earth atmosphere. The Italian Space Agency has committed a study to HTG for the analysis of the destructive phase of the uncontrolled atmospheric re-entry by means of a dedicated European software tool (SCARAB). The expected outputs will be used in order to determine how much of the spacecraft and how many fragments parts of it will reach the ground on the equatorial earth zone. This paper will address the peculiarities of the spacecraft initial status, its risks at end of life and the SCARAB modelling as well as its 6D flight dynamics re-entry analysis results also in terms of the destruction history tree. Consideration will be made on the ground dispersion and casualt y area due to the very restricted equatorial zone impacted. References B. Fritsche, H. Klinkrad, A. Kashkovsky, E.Grinberg; Spacecraft Disintegration during uncontrolled atmospheric entry ; IAA-99-IAA.6.7.02; 50t h IAC 4-8 Oct. 1999

  12. Developing international market entry strategy for cultural tourism of Turkey

    Directory of Open Access Journals (Sweden)

    Faruk Alaeddinoğlu

    2009-03-01

    Full Text Available The aims of this paper are to examine potential international markets for culture tourism of Turkey and to determine a mode of entry strategy for it. The structure of this paper includes screening, identification, and selection stage based on applied various analysis, techniques, methods, and statistics. The major findings here suggest that South Korea and Canada are two possible foreign markets to penetrate. After deeply analysis of South Korea and Canada outbound tourism market, opening overseas tourism promotion office and applying agency are recommended as an appropriate mode of entry strategy for them, respectively. In this regard, practical implications are also mentioned for Destination Marketing Organisation of Turkey.

  13. Geometry of Weyl theory for Jacobi matrices with matrix entries

    CERN Document Server

    Schulz-Baldes, Hermann

    2008-01-01

    A Jacobi matrix with matrix entries is a self-adjoint block tridiagonal matrix with invertible blocks on the off-diagonals. The Weyl surface describing the dependence of Green's matrix on the boundary conditions is interpreted as the set of maximally isotropic subspace of a quadratic from given by the Wronskian. Analysis of the possibly degenerate limit quadratic form leads to the limit point/limit surface theory of maximal symmetric extensions for semi-infinite Jacobi matrices with matrix entries with arbitrary deficiency indices. The resolvent of the extensions is explicitly calculated.

  14. Entry, Descent and Landing Systems Analysis Study: Phase 1 Report

    Science.gov (United States)

    DwyerCianciolo, Alicia M.; Davis, Jody L.; Komar, David R.; Munk, Michelle M.; Samareh, Jamshid A.; Powell, Richard W.; Shidner, Jeremy D.; Stanley, Douglas O.; Wilhite, Alan W.; Kinney, David J.; McGuire, M. Kathleen; Arnold, James O.; Howard, Austin R.; Sostaric, Ronald R.; Studak, Joseph W.; Zumwalt, Carlie H.; Llama, Eduardo G.; Casoliva, Jordi; Ivanov, Mark C.; Clark, Ian; Sengupta, Anita

    2010-01-01

    NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to make in order to successfully land large payloads at Mars for both robotic and human-scale missions. This paper summarizes the motivation, approach and top-level results from Year 1 of the study, which focused on landing 10-50 mt on Mars, but also included a trade study of the best advanced parachute design for increasing the landed payloads within the EDL architecture of the Mars Science Laboratory (MSL) mission

  15. Experience of a Medicaid nursing home entry cohort

    Science.gov (United States)

    Ray, Wayne A.; Federspiel, Charles F.; Baugh, David K.; Dodds, Suzanne

    1989-01-01

    Long-term care cost-containment policies have focused on reducing the numbers of persons entering nursing homes. To provide insight and background for such efforts, the authors studied the experience of Medicaid nursing home entry cohorts in three individual States. They found substantial interstate variation in rates of nursing home entry and subsequent patterns of discharge, suggesting the operation of fundamentally different policies for provision of Medicaid nursing home services. Analysis of the cost effectiveness and quality of care implications of these policies may provide guidance for future cost-containment efforts. PMID:10313279

  16. Venus within ESA probe reach

    Science.gov (United States)

    2006-03-01

    Venus Express mission controllers at the ESA Space Operations Centre (ESOC) in Darmstadt, Germany are making intensive preparations for orbit insertion. This comprises a series of telecommands, engine burns and manoeuvres designed to slow the spacecraft down from a velocity of 29000 km per hour relative to Venus, just before the first burn, to an entry velocity some 15% slower, allowing the probe to be captured into orbit around the planet. The spacecraft will have to ignite its main engine for 50 minutes in order to achieve deceleration and place itself into a highly elliptical orbit around the planet. Most of its 570 kg of onboard propellant will be used for this manoeuvre. The spacecraft’s solar arrays will be positioned so as to reduce the possibility of excessive mechanical load during engine ignition. Over the subsequent days, a series of additional burns will be done to lower the orbit apocentre and to control the pericentre. The aim is to end up in a 24-hour orbit around Venus early in May. The Venus orbit injection operations can be followed live at ESA establishments, with ESOC acting as focal point of interest (see attached programme). In all establishments, ESA specialists will be on hand for interviews. ESA TV will cover this event live from ESOC in Darmstadt. The live transmission will be carried free-to-air. For broadcasters, complete details of the various satellite feeds are listed at http://television.esa.int. The event will be covered on the web at venus.esa.int. The website will feature regular updates, including video coverage of the press conference and podcast from the control room at ESA’s Operations Centre. Media representatives wishing to follow the event at one of the ESA establishments listed below are requested to fill in the attached registration form and fax it back to the place of their choice. For further information, please contact: ESA Media Relations Division Tel : +33(0)1.53.69.7155 Fax: +33(0)1.53.69.7690 Venus Express

  17. IVVS probe mechanical concept design

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Paolo, E-mail: paolo.rossi@enea.it; Neri, Carlo; De Collibus, Mario Ferri; Mugnaini, Giampiero; Pollastrone, Fabio; Crescenzi, Fabio

    2015-10-15

    Highlights: • ENEA designed, developed and tested a laser based In Vessel Viewing System (IVVS). • IVVS mechanical design has been revised from 2011 to 2013 to meet ITER requirements. • Main improvements are piezoceramic actuators and a step focus system. • Successful qualification activities validated the concept design for ITER environment. - Abstract: ENEA has been deeply involved in the design, development and testing of a laser based In Vessel Viewing System (IVVS) required for the inspection of ITER plasma-facing components. The IVVS probe shall be deployed into the vacuum vessel, providing high resolution images and metrology measurements to detect damages and possible erosion. ENEA already designed and manufactured an IVVS probe prototype based on a rad-hard concept and driven by commercial micro-step motors, which demonstrated satisfying viewing and metrology performances at room conditions. The probe sends a laser beam through a reflective rotating prism. By rotating the axes of the prism, the probe can scan all the environment points except those present in a shadow cone and the backscattered light signal is then processed to measure the intensity level (viewing) and the distance from the probe (metrology). During the last years, in order to meet all the ITER environmental conditions, such as high vacuum, gamma radiation lifetime dose up to 5 MGy, cumulative neutron fluence of about 2.3 × 10{sup 17} n/cm{sup 2}, temperature of 120 °C and magnetic field of 8 T, the probe mechanical design was significantly revised introducing a new actuating system based on piezo-ceramic actuators and improved with a new step focus system. The optical and mechanical schemes have been then modified and refined to meet also the geometrical constraints. The paper describes the mechanical concept design solutions adopted in order to fulfill IVVS probe functional performance requirements considering ITER working environment and geometrical constraints.

  18. Airborne re-entry observation experiment SLIT: UV spectroscopy during STARDUST and ATV1 re-entry

    Science.gov (United States)

    Löhle, Stefan; Wernitz, Ricarda; Herdrich, Georg; Fertig, Markus; Röser, Hans-Peter; Ritter, Heiko

    2011-09-01

    Emission spectra during re-entry have been measured in 2006 for the STARDUST capsule and in 2008 for the ATV1 "Jules Verne" re-entry. This paper summarizes the approach to design the airborne UV spectroscopic setup and its modifications with respect to the missions. For the STARDUST mission, results of data analysis of data presented in 2008 are given while for the ATV1 observation first spectra of the main disruption are exemplary presented. The surface radiation during the STARDUST re-entry is used to estimate convective and radiative heat flux using different analytical models. A first look at the spectroscopic footprint of ATV1 shows that during the first explosive event, a severe break-up of the main ATV1 structure occurs. However, a correlation with an explosion of fuel could not be observed.

  19. Multiple-probe scanning probe microscopes for nanoarchitectonic materials science

    Science.gov (United States)

    Nakayama, Tomonobu; Shingaya, Yoshitaka; Aono, Masakazu

    2016-11-01

    Nanoarchitectonic systems are of interest for utilizing a vast range of nanoscale materials for future applications requiring a huge number of elemental nanocomponents. To explore the science and technology of nanoarchitectonics, advanced characterization tools that can deal with both nanoscale objects and macroscopically extended nanosystems are demanded. Multiple-probe scanning probe microscopes (MP-SPMs) are powerful tools that meet this demand because they take the advantages of conventional scanning probe microscopes and realize atomically precise electrical measurements, which cannot be done with conventional microprobing systems widely used in characterizing materials and devices. Furthermore, an MP-SPM can be used to operate some nanoarchitectonic systems. In this review, we overview the indispensable features of MP-SPMs together with the past, present and future of MP-SPM technology.

  20. Optical imaging probes in oncology.

    Science.gov (United States)

    Martelli, Cristina; Lo Dico, Alessia; Diceglie, Cecilia; Lucignani, Giovanni; Ottobrini, Luisa

    2016-07-26

    Cancer is a complex disease, characterized by alteration of different physiological molecular processes and cellular features. Keeping this in mind, the possibility of early identification and detection of specific tumor biomarkers by non-invasive approaches could improve early diagnosis and patient management.Different molecular imaging procedures provide powerful tools for detection and non-invasive characterization of oncological lesions. Clinical studies are mainly based on the use of computed tomography, nuclear-based imaging techniques and magnetic resonance imaging. Preclinical imaging in small animal models entails the use of dedicated instruments, and beyond the already cited imaging techniques, it includes also optical imaging studies. Optical imaging strategies are based on the use of luminescent or fluorescent reporter genes or injectable fluorescent or luminescent probes that provide the possibility to study tumor features even by means of fluorescence and luminescence imaging. Currently, most of these probes are used only in animal models, but the possibility of applying some of them also in the clinics is under evaluation.The importance of tumor imaging, the ease of use of optical imaging instruments, the commercial availability of a wide range of probes as well as the continuous description of newly developed probes, demonstrate the significance of these applications. The aim of this review is providing a complete description of the possible optical imaging procedures available for the non-invasive assessment of tumor features in oncological murine models. In particular, the characteristics of both commercially available and newly developed probes will be outlined and discussed.

  1. Acute - Glossary Entry - Genetics Home Reference [Genetics Home Reference (Glossary)

    Lifescience Database Archive (English)

    Full Text Available | F | G | H | I | J | K | L | M | N | O | P | Q-R | S | T | U | V | W | X | Y-Z Acute Definition(s) Having ...ding Medical Terminology . Published : October 27, 2014 Acute - Glossary Entry - Genetics Home Reference ...

  2. 76 FR 13703 - New Origin Entry Separation & Containerization Standards

    Science.gov (United States)

    2011-03-14

    ... AGENCY: Postal Service TM . ACTION: Proposed rule. SUMMARY: The Postal Service is proposing to revise... March 14, 2011 Part II Postal Service 39 CFR Part 111 New Origin Entry Separation & Containerization Standards; Proposed Rule #0;#0;Federal Register / Vol. 76 , No. 49 / Monday, March 14, 2011 / Proposed Rules...

  3. Unraveling the Entry Mechanism of Baculoviruses and Its Evolutionary Implications

    NARCIS (Netherlands)

    Wang, M.; Wang, J.; Yin, F.; Tan, Y.; Deng, F.; Chen, X.; Jehle, J.A.; Vlak, J.M.; Hu, Zhihong; Wang, H.

    2014-01-01

    The entry of baculovirus budded virus into host cells is mediated by two distinct types of envelope fusion proteins (EFPs), GP64 and F protein. Phylogenetic analysis suggested that F proteins were ancestral baculovirus EFPs, whereas GP64 was acquired by progenitor group I alphabaculovirus more recen

  4. Essays on Empirical Industrial Organization : Entry and Innovation

    NARCIS (Netherlands)

    Fernandez Machado, Roxana

    2017-01-01

    The dissertation contains three essays on empirical industrial organization devoted to studying firms' strategic interaction in different settings. The first essay develops an entry model to address an important matter in the area of urban economics: the development of cities. In particular, it

  5. The importance of prior probabilities for entry page search

    NARCIS (Netherlands)

    Kraaij, W.; Westerveld, T.; Hiemstra, D.

    2002-01-01

    Een belangrijke groep zoekopdrachten op het internet heeft ten doel de startpagina of 'entry page' van een organisatie te vinden. Zoeken naar een startpagina verschilt sterk van algemeen of 'Ad Hoc' zoeken. De resultaten van een simpel algemeen zoeksysteem zijn teleurstellend. In het rapport wordt g

  6. 50 CFR 635.41 - Products denied entry.

    Science.gov (United States)

    2010-10-01

    ... vessel listed on the ICCAT record as engaged in illegal, unreported, and unregulated fishing will be... included on the ICCAT list as engaged in illegal, unreported, and unregulated fishing will be denied entry... ICCAT convention area by a fishing vessel that is required to be listed, but not listed on the...

  7. Application of an Aesthetic Evaluation Model to Data Entry Screens.

    Science.gov (United States)

    Ngo, D. C. L.; Byrne, J. G.

    2001-01-01

    Describes a new model for quantitatively assessing screen formats. Results of applying the model to data entry screens support the use of the model. Also described is a critiquing mechanism embedded in a user interface design environment as a demonstration of this approach. (Author/AEF)

  8. Does competitive entry structurally change key marketing metrics?

    NARCIS (Netherlands)

    Kornelis, M.; Dekimpe, de M.G.; Leeflang, P.S.H.

    2008-01-01

    To what extent does competitive entry create a structural change in keymarketingmetrics? New players may just be a temporal nuisance to incumbents, but could also fundamentally change the latter's performance evolution, or induce them to permanently alter their spending levels and/or pricing decisio

  9. Does competitive entry structurally change key marketing metrics?

    NARCIS (Netherlands)

    Kornelis, Marcel; Dekimpe, Marnik G.; Leeflang, Peter S. H.

    2008-01-01

    To what extent does competitive entry create a structural change in key marketing metrics? New players mayjust be a temporal nuisance to incumbents, but could also fundamentally change the latter's performance evolution, or induce them to permanently alter their spending levels and/or pricing decisi

  10. Entry Level Systems Analysts: What Does the Industry Want?

    Directory of Open Access Journals (Sweden)

    Donna M. Grant

    2016-06-01

    Full Text Available This study investigates the skill sets necessary for entry level systems analysts. Towards this end, the study combines two sources of data, namely, a content analysis of 200 systems analysts’ online job advertisements and a survey of 20 senior Information Systems (IS professionals. Based on Chi-square tests, the results reveal that most employers prefer entry level systems analysts with an undergraduate Computer Science degree. Furthermore, most of the employers prefer entry level systems analysts to have some years of experience as well as industry certifications. The results also reveal that there is a higher preference for entry level systems analysts who have non-technical and people skills (e.g., problem solving and oral communication. The empirical results from this study will inform IS educators as they develop future systems analysts. Additionally, the results will be useful to the aspiring systems analysts who need to make sure that they have the necessary job skills before graduating and entering the labor market.

  11. Detecting entanglement of states by entries of their density matrices

    CERN Document Server

    Qi, Xiaofei

    2010-01-01

    For any bipartite systems, a universal entanglement witness of rank-4 for pure states is obtained and a class of finite rank entanglement witnesses is constructed. In addition, a method of detecting entanglement of a state only by entries of its density matrix is obtained.

  12. Handling Qualities of a Capsule Spacecraft During Atmospheric Entry

    Science.gov (United States)

    Bilimoria, Karl D.; Mueller, Eric R.

    2010-01-01

    A piloted simulation was conducted to study handling qualities for capsule spacecraft entering the Earth s atmosphere. Eight evaluation pilots, including six pilot astronauts, provided Cooper-Harper ratings, workload ratings, and qualitative comments. The simulation began after descending through the atmospheric entry interface point and continued until the drogue parachutes deployed. There were two categories of piloting tasks, both of which required bank angle control. In one task category, the pilot followed a closed-loop bank angle command computed by the backup guidance system to manage g-loads during entry. In the other task category, the pilot used intuitive rules to determine the desired bank angle independently, based on an open-loop schedule of vertical speed, Mach, and total energy specified at several range-to-target gates along the entry trajectory. Pilots were able to accurately track the bank angle guidance commands and steered the capsule toward the recovery site with essentially the same range error as the benchmark autopilot trajectory albeit with substantially higher propellant usage, and the handling qualities for this task were satisfactory. Another key result was that the complex piloting task of atmospheric entry could be performed satisfactorily, even in the presence of large dispersions, by controlling bank angle to follow a simple open-loop schedule.

  13. Customizable tool for ecological data entry, assessment, monitoring, and interpretation

    Science.gov (United States)

    The Database for Inventory, Monitoring and Assessment (DIMA) is a highly customizable tool for data entry, assessment, monitoring, and interpretation. DIMA is a Microsoft Access database that can easily be used without Access knowledge and is available at no cost. Data can be entered for common, nat...

  14. 19 CFR 10.100 - Entry, examination, and tariff status.

    Science.gov (United States)

    2010-04-01

    ...; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. General Provisions United States Government Importations § 10.100 Entry, examination, and tariff status. Except as otherwise..., importations made by or for the account of any agency or office of the United States Government are subject...

  15. Early versus Late Entry to Preschool: Some Developmental Implications

    Science.gov (United States)

    Zupancic, Maja; Kavcic, Tina

    2004-01-01

    This study explores the relationship between cognitive, motor, social and personality development of 3-year-old children and the age of their entry into preschool, which ranged from 10 to 45 months. 247 children from 17 preschools in different regions of Slovenia, all implementing the same National Curriculum, participated. Preschool teachers…

  16. The Entrepreneurial Process: An International Analysis of Entry and Exit

    NARCIS (Netherlands)

    P.W. van der Zwan (Peter)

    2011-01-01

    textabstractThis thesis deals with the entrepreneurial process from an international perspective. The first part explores which people decide to enter entrepreneurship. A distinction is made between two modes of entrepreneurial entry: taking over an existing firm and starting a new firm. The second

  17. 19 CFR 147.43 - Entry under the Customs laws.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Entry under the Customs laws. 147.43 Section 147.43 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF... the Customs laws. (a) Payment of duties and taxes. Any applicable duties and internal revenue taxes...

  18. SME's perceptions regarding strategic and structural entry barriers

    NARCIS (Netherlands)

    Lutz, Clemens; Kemp, Ron; Dijkstra, S. Gerhard

    2007-01-01

    Abstract Extant literature discusses a large number of different entry barriers that may hamper market efficiency or entrepreneurial activity. In practice several of these barriers cohere and stem from the same root. Factor analysis is used to identify the underlying dimensions of these barriers. 7

  19. Partial Acquistion as an Entry Mode in Transition Economies

    DEFF Research Database (Denmark)

    Jakobsen, Kristian; Meyer, Klaus E.

    2007-01-01

    Multinational enterprises often acquire stakes in an existing enterprise when entering emerging economies. This paper examines the determinants of entry mode choices with a special focus on these partial acquisitions, which have received little attention in the scholarly literature. We show that ...

  20. Widening Participation and Contextual Entry Policy in Accounting and Finance

    Science.gov (United States)

    Rowbottom, N.

    2017-01-01

    The paper examines the performance of accounting and finance students entering university via a "widening participation" scheme that seeks to attract students who have been historically under-represented in higher education. Focus is placed on the policy of providing contextual entry offers that recognise that academic qualifications be…

  1. 9 CFR 93.806 - Animals refused entry.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Animals refused entry. 93.806 Section 93.806 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EXPORTATION AND IMPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION...

  2. Childhood cancer survivors' school (re)entry: Australian parents' perceptions.

    Science.gov (United States)

    McLoone, J K; Wakefield, C E; Cohn, R J

    2013-07-01

    Starting or returning to school after intense medical treatment can be academically and socially challenging for childhood cancer survivors. This study aimed to evaluate the school (re)entry experience of children who had recently completed cancer treatment. Forty-two semi-structured telephone interviews were conducted to explore parents' perceptions of their child's (re)entry to school after completing treatment (23 mothers, 19 fathers, parent mean age 39.5 years; child mean age 7.76 years). Interviews were analysed using the framework of Miles and Huberman and emergent themes were organised using QSR NVivo8. Parents closely monitored their child's school (re)entry and fostered close relationships with their child's teacher to ensure swift communication of concerns should they arise. The most commonly reported difficulty related to aspects of peer socialisation; survivors either displayed a limited understanding of social rules such as turn taking, or related more to older children or teachers relative to their peers. Additionally, parents placed a strong emphasis on their child's overall personal development, above academic achievement alone. Improved parent, clinician and teacher awareness of the importance of continued peer socialisation during the treatment period is recommended in order to limit the ongoing ramifications this may have on school (re)entry post-treatment completion.

  3. Risk Factors for Mosquito House Entry in the Lao PDR

    NARCIS (Netherlands)

    Hiscox, A.F.; Khammanithong, P.; Kaul, S.; Sananikhom, P.; Luthi, R.; Hill, N.; Brey, P.T.; Lindsay, S.W.

    2013-01-01

    Background Construction of the Nam Theun 2 hydroelectric project and flooding of a 450 km2 area of mountain plateau in south-central Lao PDR resulted in the resettlement of 6,300 people to newly built homes. We examined whether new houses would have altered risk of house entry by mosquitoes compared

  4. Macropinocytosis is the Entry Mechanism of Amphotropic Murine Leukemia Virus

    DEFF Research Database (Denmark)

    Rasmussen, Izabela; Vilhardt, Frederik

    2015-01-01

    The entry mechanism of murine amphotropic retrovirus (A-MLV) has not been unambiguously determined. We show here that A-MLV does not internalize by caveolae or other pinocytic mechanism, but by macropinocytosis. Thus A-MLV infection of mouse embryonic fibroblasts deficient for caveolin or dynamin...

  5. 40 CFR 86.1849-01 - Right of entry.

    Science.gov (United States)

    2010-07-01

    ... Complete Otto-Cycle Heavy-Duty Vehicles § 86.1849-01 Right of entry. (a) Any manufacturer who has applied for certification of a new motor vehicle subject to testing under this subpart, or any manufacturer or... activities connected with such testing are or were performed. (2) Any facility where any new motor vehicle...

  6. 25 CFR 227.12 - Mineral reserves in nonmineral entries.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Mineral reserves in nonmineral entries. 227.12 Section 227.12 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF CERTAIN LANDS IN WIND RIVER INDIAN RESERVATION, WYOMING, FOR OIL AND GAS MINING How to Acquire...

  7. Risk Factors for Mosquito House Entry in the Lao PDR

    NARCIS (Netherlands)

    Hiscox, A.F.; Khammanithong, P.; Kaul, S.; Sananikhom, P.; Luthi, R.; Hill, N.; Brey, P.T.; Lindsay, S.W.

    2013-01-01

    Background Construction of the Nam Theun 2 hydroelectric project and flooding of a 450 km2 area of mountain plateau in south-central Lao PDR resulted in the resettlement of 6,300 people to newly built homes. We examined whether new houses would have altered risk of house entry by mosquitoes compared

  8. Spectral averaging techniques for Jacobi matrices with matrix entries

    CERN Document Server

    Sadel, Christian

    2009-01-01

    A Jacobi matrix with matrix entries is a self-adjoint block tridiagonal matrix with invertible blocks on the off-diagonals. Averaging over boundary conditions leads to explicit formulas for the averaged spectral measure which can potentially be useful for spectral analysis. Furthermore another variant of spectral averaging over coupling constants for these operators is presented.

  9. Public University Entry in Ghana: Is It Equitable?

    Science.gov (United States)

    Yusif, Hadrat; Yussof, Ishak; Osman, Zulkifly

    2013-01-01

    Public universities in Ghana are highly subsidised by the central government and account for about 80 per cent of university students in the country. Yet issues of fairness in terms of entry into the public university system have so far hardly been addressed. To find out whether participation in public university education is equitable, the…

  10. Oblique water entry of a three dimensional body

    Directory of Open Access Journals (Sweden)

    Scolan Yves-Marie

    2014-12-01

    Full Text Available The problem of the oblique water entry of a three dimensional body is considered. Wagner theory is the theoretical framework. Applications are discussed for an elliptic paraboloid entering an initially flat free surface. A dedicated experimental campaign yields a data base for comparisons. In the present analysis, pressure, force and dynamics of the wetted surface expansion are assessed.

  11. Late entry to antenatal care in New South Wales, Australia

    Directory of Open Access Journals (Sweden)

    Rubin George

    2006-08-01

    Full Text Available Abstract Aims This study aimed to assess the prevalence of women who entered antenatal care (ANC late and to identify factors related to the late entry to ANC in New South Wales (NSW in 2004. Methods The NSW Midwives Data Collection contained data of 85,034 women who gave birth in 2004. Data were downloaded using SAS and transferred to STATA 8.0. Entering ANC after 12 weeks of gestation was classified as late. The Andersen Health Seeking Behaviour Model was used for selection and analyses of related factors. Regression and hierarchical analyses were used to identify significant factors and their relative contributions to the variation of pregnancy duration at entry to ANC. Results 41% of women commenced ANC after 12 weeks of gestation. Inequality existed between groups of women with predisposing characteristics and enabling resources contributed more to the variation in pregnancy duration at entry to ANC than needs. The groups of women with highest risk were teenagers, migrants from developing countries, women living in Western Sydney, Aboriginal and Torres Strait Islanders, women with three or more previous pregnancies and heavy smokers. The high risk groups with largest number of women were migrants from developing countries and women living in Western Sydney. Conclusion A large number of women in NSW entered ANC late in their pregnancies. Efforts to increase early entry to ANC should be targeted on identified high risk groups of women.

  12. Human Mars Entry, Descent and Landing Architectures Study Overview

    Science.gov (United States)

    Polsgrove, Tara T.; Dwyer Cianciolo, Alicia

    2016-01-01

    Landing humans on Mars will require entry, descent and landing (EDL) capability beyond the current state of the art. Nearly twenty times more delivered payload and an order of magnitude improvement in precision landing capability will be necessary. Several EDL technologies capable of meeting the human class payload delivery requirements are being considered. The EDL technologies considered include low lift-to-drag vehicles like Hypersonic Inflatable Aerodynamic Decelerators (HIAD), Adaptable Deployable Entry and Placement Technology (ADEPT), and mid range lift-to-drag vehicles like rigid aeroshell configurations. To better assess EDL technology options and sensitivities to future human mission design variations, a series of design studies has been conducted. The design studies incorporate EDL technologies with conceptual payload arrangements defined by the Evolvable Mars Campaign to evaluate the integrated system with higher fidelity than have been performed to date. This paper describes the results of the design studies for a lander design using the HIAD, ADEPT and rigid shell entry technologies and includes system and subsystem design details including mass and power estimates. This paper will review the point design for three entry configurations capable of delivering a 20 t human class payload to the surface of Mars.

  13. Integrated alarm annunciation and entry control systems -- Survey results

    Energy Technology Data Exchange (ETDEWEB)

    Clever, J.J.; Arakaki, L.H.; Monaco, F.M.; Juarros, L.E.; Quintana, G.R.

    1993-10-01

    This report provides the results and analyses of a detailed survey undertaken in Summer 1993 to address integrated intrusion detection alarm annunciation and entry control system issues. This survey was undertaken as a first attempt toward beginning to answer questions about integrated systems and commercial capabilities to meet or partially meet US Department of Energy (DOE) site needs.

  14. Does competitive entry structurally change key marketing metrics?

    NARCIS (Netherlands)

    Kornelis, Marcel; Dekimpe, Marnik G.; Leeflang, Peter S. H.

    To what extent does competitive entry create a structural change in key marketing metrics? New players mayjust be a temporal nuisance to incumbents, but could also fundamentally change the latter's performance evolution, or induce them to permanently alter their spending levels and/or pricing

  15. Wigner law for matrices with dependent entries - a perturbative approach

    CERN Document Server

    Krajewski, T; Vu, D L

    2016-01-01

    We show that Wigner semi-circle law holds for Hermitian matrices with dependent entries, provided the deviation of the cumulants from the normalised Gaussian case obeys a simple power law bound in the size of the matrix. To establish this result, we use replicas interpreted as a zero-dimensional quantum field theoretical model whose effective potential obey a renormalisation group equation.

  16. Potent D-Peptide Inhibitors of HIV-1 Entry

    Energy Technology Data Exchange (ETDEWEB)

    Welch,B.; VanDemark, A.; Heroux, A.; Hill, C.; Kay, M.

    2007-01-01

    During HIV-1 entry, the highly conserved gp41 N-trimer pocket region becomes transiently exposed and vulnerable to inhibition. Using mirror-image phage display and structure-assisted design, we have discovered protease-resistant D-amino acid peptides (D-peptides) that bind the N-trimer pocket with high affinity and potently inhibit viral entry. We also report high-resolution crystal structures of two of these D-peptides in complex with a pocket mimic that suggest sources of their high potency. A trimeric version of one of these peptides is the most potent pocket-specific entry inhibitor yet reported by three orders of magnitude (IC50 = 250 pM). These results are the first demonstration that D-peptides can form specific and high-affinity interactions with natural protein targets and strengthen their promise as therapeutic agents. The D-peptides described here address limitations associated with current L-peptide entry inhibitors and are promising leads for the prevention and treatment of HIV/AIDS.

  17. 46 CFR 14.305 - Entries in continuous discharge book.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Entries in continuous discharge book. 14.305 Section 14.305 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN SHIPMENT... discharge book. If the merchant mariner holds a continuous discharge book, the master or individual...

  18. 7 CFR 322.19 - Inspection; refusal of entry.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Inspection; refusal of entry. 322.19 Section 322.19 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation...

  19. 7 CFR 322.35 - Ports of entry.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Ports of entry. 322.35 Section 322.35 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation and Transit...

  20. 7 CFR 322.10 - Inspection; refusal of entry.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Inspection; refusal of entry. 322.10 Section 322.10 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation...