Radioisotopic heater units warm an interplanetary spacecraft

International Nuclear Information System (INIS)

Franco-Ferreira, E.A.

1998-01-01

The Cassini orbiter and Huygens probe, which were successfully launched on October 15, 1997, constitute NASA's last grand-scale interplanetary mission of this century. The mission, which consists of a four-year, close-up study of Saturn and its moons, begins in July 2004 with Cassini's 60 orbits of Saturn and about 33 fly-bys of the large moon Titan. The Huygens probe will descend and land on Titan. Investigations will include Saturn's atmosphere, its rings and its magnetosphere. The atmosphere and surface of Titan and other icy moons also will be characterized. Because of the great distance of Saturn from the sun, some of the instruments and equipment on both the orbiter and the probe require external heaters to maintain their temperature within normal operating ranges. These requirements are met by Light Weight Radioisotope Heater Units (LWRHUs) designed, fabricated and safety tested at Los Alamos National Laboratory, New Mexico. An improved gas tungsten arc welding procedure lowered costs and decreased processing time for heat units for the Cassini spacecraft

The role of automatic control in future interplanetary spaceflight

Science.gov (United States)

Scull, J. R.; Moore, J. W.

1976-01-01

The paper reviews the guidance and automatic control techniques used in previous U.S. and Soviet lunar and planetary exploration spacecraft, and examines the objectives and requirements of potential future interplanetary missions from the viewpoint of their further demands on automatic control technology. These missions include the Venus orbital imaging radar mission, the Pioneer Mars penetrator mission, the Mars surface sample return mission, Pioneer Saturn/Uranus/Titan probe missions, the Mariner Jupiter orbiter with daughter satellite, and comet and asteroid missions.

Return to Mercury: a global perspective on MESSENGER's first Mercury flyby.

Science.gov (United States)

Solomon, Sean C; McNutt, Ralph L; Watters, Thomas R; Lawrence, David J; Feldman, William C; Head, James W; Krimigis, Stamatios M; Murchie, Scott L; Phillips, Roger J; Slavin, James A; Zuber, Maria T

2008-07-04

In January 2008, the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft became the first probe to fly past the planet Mercury in 33 years. The encounter revealed that Mercury is a dynamic system; its liquid iron-rich outer core is coupled through a dominantly dipolar magnetic field to the surface, exosphere, and magnetosphere, all of which interact with the solar wind. MESSENGER images confirm that lobate scarps are the dominant tectonic landform and record global contraction associated with cooling of the planet. The history of contraction can be related to the history of volcanism and cratering, and the total contractional strain is at least one-third greater than inferred from Mariner 10 images. On the basis of measurements of thermal neutrons made during the flyby, the average abundance of iron in Mercury's surface material is less than 6% by weight.

LONGITUDINAL AND RADIAL DEPENDENCE OF SOLAR ENERGETIC PARTICLE PEAK INTENSITIES: STEREO, ACE, SOHO, GOES, AND MESSENGER OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Lario, D.; Ho, G. C.; Decker, R. B.; Roelof, E. C. [The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723 (United States); Aran, A. [Departament d' Astronomia i Meteorologia, Institut de Ciencies del Cosmos, Universitat de Barcelona, Barcelona (Spain); Gomez-Herrero, R.; Dresing, N.; Heber, B., E-mail: david.lario@jhuapl.edu [Institute of Experimental and Applied Physics, Christian-Albrechts University of Kiel, Kiel (Germany)

2013-04-10

Simultaneous measurements of solar energetic particle (SEP) events by two or more of the spacecraft located near 1 AU during the rising phase of solar cycle 24 (i.e., STEREO-A, STEREO-B, and near-Earth spacecraft such as ACE, SOHO, and GOES) are used to determine the longitudinal dependence of 71-112 keV electron, 0.7-3 MeV electron, 15-40 MeV proton, and 25-53 MeV proton peak intensities measured in the prompt component of SEP events. Distributions of the peak intensities for the selected 35 events with identifiable solar origin are approximated by the form exp [ - ({phi} - {phi}{sub 0}){sup 2}/2{sigma}{sup 2}], where {phi} is the longitudinal separation between the parent active region and the footpoint of the nominal interplanetary magnetic field (IMF) line connecting each spacecraft with the Sun, {phi}{sub 0} is the distribution centroid, and {sigma} determines the longitudinal gradient. The MESSENGER spacecraft, at helioradii R < 1 AU, allows us to determine a lower limit to the radial dependence of the 71-112 keV electron peak intensities measured along IMF lines. We find five events for which the nominal magnetic footpoint of MESSENGER was less than 20 Degree-Sign apart from the nominal footpoint of a spacecraft near 1 AU. Although the expected theoretical radial dependence for the peak intensity of the events observed along the same field line can be approximated by a functional form R {sup -{alpha}} with {alpha} < 3, we find two events for which {alpha} > 3. These two cases correspond to SEP events occurring in a complex interplanetary medium that favored the enhancement of peak intensities near Mercury but hindered the SEP transport to 1 AU.

MESSENGER Observations of ULF Waves in Mercury's Foreshock Region

Science.gov (United States)

Le, Guan; Chi, Peter J.; Bardsen, Scott; Blanco-Cano, Xochitl; Slavin, James A.; Korth, Haje

2012-01-01

The region upstream from a planetary bow shock is a natural plasma laboratory containing a variety of wave particle phenomena. The study of foreshocks other than the Earth s is important for extending our understanding of collisionless shocks and foreshock physics since the bow shock strength varies with heliocentric distance from the Sun, and the sizes of the bow shocks are different at different planets. The Mercury s bow shock is unique in our solar system as it is produced by low Mach number solar wind blowing over a small magnetized body with a predominately radial interplanetary magnetic field. Previous observations of Mercury upstream ultra-low frequency (ULF) waves came exclusively from two Mercury flybys of Mariner 10. The MESSENGER orbiter data enable us to study of upstream waves in the Mercury s foreshock in depth. This paper reports an overview of upstream ULF waves in the Mercury s foreshock using high-time resolution magnetic field data, 20 samples per second, from the MESSENGER spacecraft. The most common foreshock waves have frequencies near 2 Hz, with properties similar to the 1-Hz waves in the Earth s foreshock. They are present in both the flyby data and in every orbit of the orbital data we have surveyed. The most common wave phenomenon in the Earth s foreshock is the large-amplitude 30-s waves, but similar waves at Mercury have frequencies at 0.1 Hz and occur only sporadically with short durations (a few wave cycles). Superposed on the "30-s" waves, there are spectral peaks at 0.6 Hz, not reported previously in Mariner 10 data. We will discuss wave properties and their occurrence characteristics in this paper.

Dynamical Messengers for Gauge Mediation

Energy Technology Data Exchange (ETDEWEB)

Hook, Anson; Torroba, Gonzalo; /SLAC /Stanford U., Phys. Dept.

2011-08-17

We construct models of indirect gauge mediation where the dynamics responsible for breaking supersymmetry simultaneously generates a weakly coupled subsector of messengers. This provides a microscopic realization of messenger gauge mediation where the messenger and hidden sector fields are unified into a single sector. The UV theory is SQCD with massless and massive quarks plus singlets, and at low energies it flows to a weakly coupled quiver gauge theory. One node provides the primary source of supersymmetry breaking, which is then transmitted to the node giving rise to the messenger fields. These models break R-symmetry spontaneously, produce realistic gaugino and sfermion masses, and give a heavy gravitino.

LONGITUDINAL AND RADIAL DEPENDENCE OF SOLAR ENERGETIC PARTICLE PEAK INTENSITIES: STEREO, ACE, SOHO, GOES, AND MESSENGER OBSERVATIONS

International Nuclear Information System (INIS)

Lario, D.; Ho, G. C.; Decker, R. B.; Roelof, E. C.; Aran, A.; Gómez-Herrero, R.; Dresing, N.; Heber, B.

2013-01-01

Simultaneous measurements of solar energetic particle (SEP) events by two or more of the spacecraft located near 1 AU during the rising phase of solar cycle 24 (i.e., STEREO-A, STEREO-B, and near-Earth spacecraft such as ACE, SOHO, and GOES) are used to determine the longitudinal dependence of 71-112 keV electron, 0.7-3 MeV electron, 15-40 MeV proton, and 25-53 MeV proton peak intensities measured in the prompt component of SEP events. Distributions of the peak intensities for the selected 35 events with identifiable solar origin are approximated by the form exp [ – (φ – φ 0 ) 2 /2σ 2 ], where φ is the longitudinal separation between the parent active region and the footpoint of the nominal interplanetary magnetic field (IMF) line connecting each spacecraft with the Sun, φ 0 is the distribution centroid, and σ determines the longitudinal gradient. The MESSENGER spacecraft, at helioradii R –α with α 3. These two cases correspond to SEP events occurring in a complex interplanetary medium that favored the enhancement of peak intensities near Mercury but hindered the SEP transport to 1 AU.

Global Optimization of Interplanetary Missions with, Hybrid Propulsion, Multi-Stage Spacecraft, Aerocapture, and Planetary Atmospheric Probes

Data.gov (United States)

National Aeronautics and Space Administration — The purpose of this IRAD is to expand the capability of Goddard’s interplanetary trajectory preliminary design tool, the Evolutionary Mission Trajectory Generator...

Solar and interplanetary disturbances

CERN Document Server

Alurkar, S K

1997-01-01

Over the last three decades, a spate of solar wind observations have been made with sophisticated ground-based and space-borne instruments. Two highly successful space missions of the Skylab and the twin spacecraft Helios 1 and 2 have amassed an invaluable wealth of information on the large scale structure of the inner heliosphere, the solar and interplanetary magnetic field, coronal holes, interplanetary dust, solar windflows, etc.Solar and interplanetary propagating phenomena have been extensively studied during the last two decades. Very recently, a new simple model based on results from a

The Messenger Mission to Mercury

CERN Document Server

Domingue, D. L

2007-01-01

NASA’s MESSENGER mission, launched on 3 August, 2004 is the seventh mission in the Discovery series. MESSENGER encounters the planet Mercury four times, culminating with an insertion into orbit on 18 March 2011. It carries a comprehensive package of geophysical, geological, geochemical, and space environment experiments to complete the complex investigations of this solar-system end member, which begun with Mariner 10. The articles in this book, written by the experts in each area of the MESSENGER mission, describe the mission, spacecraft, scientific objectives, and payload. The book is of interest to all potential users of the data returned by the MESSENGER mission, to those studying the nature of the planet Mercury, and by all those interested in the design and implementation of planetary exploration missions.

The Ring Current Response to Solar and Interplanetary Storm Drivers

Science.gov (United States)

Mouikis, C.; Kistler, L. M.; Bingham, S.; Kronberg, E. A.; Gkioulidou, M.; Huang, C. L.; Farrugia, C. J.

2014-12-01

The ring current responds differently to the different solar and interplanetary storm drivers such as coronal mass injections, (CME's), corotating interaction regions (CIR's), high-speed streamers and other structures. The resulting changes in the ring current particle pressure, in turn, change the global magnetic field, controlling the transport of the radiation belts. To quantitatively determine the field changes during a storm throughout the magnetosphere, it is necessary to understand the transport, sources and losses of the particles that contribute to the ring current. Because the measured ring current energy spectra depend not only on local processes, but also on the history of the ions along their entire drift path, measurements of ring current energy spectra at two or more locations can be used to strongly constrain the time dependent magnetic and electric fields. In this study we use data predominantly from the Cluster and the Van Allen Probes, covering more than a full solar cycle (from 2001 to 2014). For the period 2001-2012, the Cluster CODIF and RAPID measurements of the inner magnetosphere are the primary data set used to monitor the storm time ring current variability. After 2012, the Cluster data set complements the data from the Van Allen Probes HOPE and RBSPICE instruments, providing additional measurements from different MLT and L shells. Selected storms from this periods, allow us to study the ring current dynamics and pressure changes, as a function of L shell, magnetic local time, and the type of interplanetary disturbances.

MESSENGER'S First Flyby of Mercury

Science.gov (United States)

Slavin, James A.

2008-01-01

The MESSENGER mission to Mercury offers our first opportunity to explore this planet's miniature magnetosphere since Mariner 10's brief fly-bys in 1974-5. The magnetosphere of Mercury is the smallest in the solar system with its magnetic field typically standing off the solar wind only - 1000 to 2000 km above the surface. An overview of the MESSENGER mission and its January 14th close flyby of Mercury will be provided. Primary science objectives and the science instrumentation will be described. Initial results from MESSENGER'S first flyby on January 14th, 2008 will be discussed with an emphasis on the magnetic field and charged particle measurements.

Translational Influence on Messenger Stability

DEFF Research Database (Denmark)

Eriksen, Mette

-termination to be a global phenomena in gene regulation. The influence of codon usage in the early coding region on messenger stability was examined, in order to establish how fast or slow the ribosome has to decode the sequence for it to protect the messenger from degradation. The experiments demonstrated that very fast...

Localization of calcium-binding proteins and GABA transporter (GAT-1) messenger RNA in the human subthalamic nucleus

International Nuclear Information System (INIS)

Augood, S.J.; Waldvogel, H.J.; Muenkle, M.C.; Faull, R.L.M.; Emson, P.C.

1999-01-01

The distribution of messenger RNA encoding the human GAT-1 (a high-affinity GABA transporter) was investigated in the subthalamic nucleus of 10 neurologically normal human post mortem cases. Further, the distribution of messenger RNA and protein encoding the three neuronally expressed calcium-binding proteins (calbindin D28k, parvalbumin and calretinin) was similarly investigated using in situ hybridization and immunohistochemical techniques. Cellular sites of calbindin D28k, parvalbumin, calretinin and GAT-1 messenger RNA expression were localized using human-specific oligonucleotide probes radiolabelled with [ 35 S]dATP. Sites of protein localization were visualized using specific anti-calbindin D28k, anti-parvalbumin and anti-calretinin antisera. Examination of emulsion-coated tissue sections processed for in situ hybridization revealed an intense signal for GAT-1 messenger RNA within the human subthalamic nucleus, indeed the majority of Methylene Blue-counterstained cells were enriched in this transcript. Further, a marked heterogeneity was noted with regard to the expression of the messenger RNA's encoding the three calcium-binding proteins; this elliptical nucleus was highly enriched in parvalbumin messenger RNA-positive neurons and calretinin mRNA-positive cells but not calbindin messenger RNA-positive cells. Indeed, only an occasional calbindin messenger RNA-positive cell was detected within the mediolateral extent of the nucleus. In marked contrast, numerous parvalbumin messenger RNA-positive cells and calretinin messenger RNA-positive cells were detected and they were topographically distributed; parvalbumin messenger RNA-positive cells were highly enriched in the dorsal subthalamic nucleus extending mediolaterally; calretinin messenger RNA-positive cells were more enriched ventrally although some degree of overlap was apparent. Computer-assisted analysis of the average cross-sectional somatic area of parvalbumin, calretinin and GAT-1 messenger RNA

Higgs mass from neutrino-messenger mixing

International Nuclear Information System (INIS)

Byakti, Pritibhajan; Khosa, Charanjit K.; Mummidi, V.S.; Vempati, Sudhir K.

2017-01-01

The discovery of the Higgs particle at 125 GeV has put strong constraints on minimal messenger models of gauge mediation, pushing the stop masses into the multi-TeV regime. Extensions of these models with matter-messenger mixing terms have been proposed to generate a large trilinear parameter, A t , relaxing these constraints. The detailed survey of these models (DOI: 10.1007/JHEP05(2013)055; 10.1007/JHEP08(2013)093 ) so far considered messenger mixings with only MSSM superfields. In the present work, we extend the survey to MSSM with inverse-seesaw mechanism. The neutrino-sneutrino corrections to the Higgs mass in the inverse seesaw model are not significant in the minimal gauge mediation model, unless one considers messenger-matter interaction terms. We classify all possible models with messenger-matter interactions and perform thorough numerical analysis to find out the promising models. We found that out of the 17 possible models 9 of them can lead to Higgs mass within the observed value without raising the sfermion masses significantly. The successful models have stop masses ∼1.5 TeV with small or negligible mixing and yet a light CP even Higgs at 125 GeV.

Radio images of the interplanetary turbulent plasma

International Nuclear Information System (INIS)

Vlasov, V.I.

1979-01-01

The results of the interplanetary scintillation daily observations of approximately 140 radio sources are given. The observations were carried out at the radiotelescope VLPA FIAN during 24 days in October-November 1975 and 6 days in April 1976. The maps (radio images) of interplanetary turbulent plasma are presented. The analysis of the maps reveals the presence of large-scale irregularities in the interplanetary plasma. The variability in large-scale structure of the interplanetary plasma is due mainly to transport of matter from the Sun. A comparison of the scintillation with the geomagnetic activity index detected the presence of a straight connection between them

Lunar and interplanetary trajectories

CERN Document Server

Biesbroek, Robin

2016-01-01

This book provides readers with a clear description of the types of lunar and interplanetary trajectories, and how they influence satellite-system design. The description follows an engineering rather than a mathematical approach and includes many examples of lunar trajectories, based on real missions. It helps readers gain an understanding of the driving subsystems of interplanetary and lunar satellites. The tables and graphs showing features of trajectories make the book easy to understand. .

MESSENGER Magnetic Field Observations of Upstream Ultra-Low Frequency Waves at Mercury

Science.gov (United States)

Le, G.; Chi, P. J.; Boardsen, S.; Blanco-Cano, X.; Anderosn, B. J.; Korth, H.

2012-01-01

The region upstream from a planetary bow shock is a natural plasma laboratory containing a variety of wave particle phenomena. The study of foreshocks other than the Earth's is important for extending our understanding of collisionless shocks and foreshock physics since the bow shock strength varies with heliocentric distance from the Sun, and the sizes of the bow shocks are different at different planets. The Mercury's bow shock is unique in our solar system as it is produced by low Mach number solar wind blowing over a small magnetized body with a predominately radial interplanetary magnetic field. Previous observations of Mercury upstream ultra-low frequency (ULF) waves came exclusively from two Mercury flybys of Mariner 10. The MESSENGER orbiter data enable us to study of upstream waves in the Mercury's foreshock in depth. This paper reports an overview of upstream ULF waves in the Mercury's foreshock using high-time resolution magnetic field data, 20 samples per second, from the MESSENGER spacecraft. The most common foreshock waves have frequencies near 2 Hz, with properties similar to the I-Hz waves in the Earth's foreshock. They are present in both the flyby data and in every orbit of the orbital data we have surveyed. The most common wave phenomenon in the Earth's foreshock is the large-amplitude 30-s waves, but similar waves at Mercury have frequencies at near 0.1 Hz and occur only sporadically with short durations (a few wave cycles). Superposed on the "30-s" waves, there are spectral peaks at near 0.6 Hz, not reported previously in Mariner 10 data. We will discuss wave properties and their occurrence characteristics in this paper.

Messengers of the universe

International Nuclear Information System (INIS)

Becker, J.K.; Spurio, M.

2011-01-01

The observation of the solar neutrinos and of a neutrino burst from the supernova explosion 1987A opened a new observation field which in the next years could be complemented with the detection of astrophysical highenergy neutrinos. Neutrino astronomy is a young discipline derived from the fundamental necessity of extending conventional astronomy beyond the usual electro-magnetic messengers. This is a summary of recent results on those new 'messengers of the universe', based on the presentations in Branch IV of the Neutrino Oscillation Workshop 2010 (NOW2010).

Higgs mass from neutrino-messenger mixing

Energy Technology Data Exchange (ETDEWEB)

Byakti, Pritibhajan [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India); Department of Theoretical Physics, Indian Association for the Cultivation of Science,2A & 2B Raja S.C. Mullick Road, Kolkata 700 032 (India); Khosa, Charanjit K. [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India); Mummidi, V.S. [Harish-Chandra Research Institute,Chhatnag Road, Jhusi, Allahabad 211019 (India); Vempati, Sudhir K. [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India)

2017-03-06

The discovery of the Higgs particle at 125 GeV has put strong constraints on minimal messenger models of gauge mediation, pushing the stop masses into the multi-TeV regime. Extensions of these models with matter-messenger mixing terms have been proposed to generate a large trilinear parameter, A{sub t}, relaxing these constraints. The detailed survey of these models (DOI: 10.1007/JHEP05(2013)055; 10.1007/JHEP08(2013)093 ) so far considered messenger mixings with only MSSM superfields. In the present work, we extend the survey to MSSM with inverse-seesaw mechanism. The neutrino-sneutrino corrections to the Higgs mass in the inverse seesaw model are not significant in the minimal gauge mediation model, unless one considers messenger-matter interaction terms. We classify all possible models with messenger-matter interactions and perform thorough numerical analysis to find out the promising models. We found that out of the 17 possible models 9 of them can lead to Higgs mass within the observed value without raising the sfermion masses significantly. The successful models have stop masses ∼1.5 TeV with small or negligible mixing and yet a light CP even Higgs at 125 GeV.

MESSENGER Observations of Extreme Magnetic Tail Loading and Unloading During its Third Flyby of Mercury: Substorms?

Science.gov (United States)

Slavin, James A.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Gloeckler, George; Krimigis, Stamatios M.; McNutt, Ralph L., Jr.; Schriver, David; Solomon, Sean C.; Zurbuchen, Thomas H.

2010-01-01

During MESSENGER's third flyby of Mercury on September 29, 2009, a variable interplanetary magnetic field produced a series of several minute enhancements of the tail magnetic field hy factors of approx. 2 to 3.5. The magnetic field flaring during these intervals indicates that they result from loading of the tail with magnetic flux transferred from the dayside magnetosphere. The unloading intervals were associated with plasmoids and traveling compression regions, signatures of tail reconnection. The peak tail magnetic flux during the smallest loading events equaled 30% of the magnetic flux emanating from Mercury, and may have reached 100% for the largest event. In this case the dayside magnetic shielding is reduced and solar wind flux impacting the surface may be greatly enhanced. Despite the intensity of these events and their similarity to terrestrial substorm magnetic flux dynamics, no energetic charged particles with energies greater than 36 keV were observed.

Sweet Spot Supersymmetry and Composite Messengers

International Nuclear Information System (INIS)

Ibe, Masahiro; Kitano, Ryuichiro

2007-01-01

Sweet spot supersymmetry is a phenomenologically and cosmologically perfect framework to realize a supersymmetric world at short distance. We discuss a class of dynamical models of supersymmetry breaking and its mediation whose low-energy effective description falls into this framework. Hadron fields in the dynamical models play a role of the messengers of the supersymmetry breaking. As is always true in the models of the sweet spot supersymmetry, the messenger scale is predicted to be 10 5 GeV ∼ mess ∼ 10 GeV. Various values of the effective number of messenger fields N mess are possible depending on the choice of the gauge group

Mercury's Reference Frames After the MESSENGER Mission

Science.gov (United States)

Stark, A.; Oberst, J.; Preusker, F.; Burmeister, S.; Steinbrügge, G.; Hussmann, H.

2018-05-01

We provide an overview of Mercury's reference frames based on MESSENGER observations. We discuss the dynamical, the principal-axes, the ellipsoid, as well as the cartographic frame, which was adopted for MESSENGER data products.

Interplanetary Magnetic Field Guiding Relativistic Particles

Science.gov (United States)

Masson, S.; Demoulin, P.; Dasso, S.; Klein, K. L.

2011-01-01

The origin and the propagation of relativistic solar particles (0.5 to few Ge V) in the interplanetary medium remains a debated topic. These relativistic particles, detected at the Earth by neutron monitors have been previously accelerated close to the Sun and are guided by the interplanetary magnetic field (IMF) lines, connecting the acceleration site and the Earth. Usually, the nominal Parker spiral is considered for ensuring the magnetic connection to the Earth. However, in most GLEs the IMF is highly disturbed, and the active regions associated to the GLEs are not always located close to the solar footprint of the nominal Parker spiral. A possible explanation is that relativistic particles are propagating in transient magnetic structures, such as Interplanetary Coronal Mass Ejections (ICMEs). In order to check this interpretation, we studied in detail the interplanetary medium where the particles propagate for 10 GLEs of the last solar cycle. Using the magnetic field and the plasma parameter measurements (ACE/MAG and ACE/SWEPAM), we found widely different IMF configurations. In an independent approach we develop and apply an improved method of the velocity dispersion analysis to energetic protons measured by SoHO/ERNE. We determined the effective path length and the solar release time of protons from these data and also combined them with the neutron monitor data. We found that in most of the GLEs, protons propagate in transient magnetic structures. Moreover, the comparison between the interplanetary magnetic structure and the interplanetary length suggest that the timing of particle arrival at Earth is dominantly determined by the type of IMF in which high energetic particles are propagating. Finally we find that these energetic protons are not significantly scattered during their transport to Earth.

Mobile MSN Messenger: Still a Complement?

Directory of Open Access Journals (Sweden)

Marcus Nyberg

2008-10-01

Full Text Available In order to understand how mobile instant messaging services can fit into the users’ current communication behavior, Ericsson Research performed a qualitative user study in Sweden in May 2007. The results showed that the respondents were positive towards (free of charge mobile MSN Messenger and perceived it as an ex¬tension of the computer-based version that could be used anywhere. However, although MSN Messenger on the com¬puter definitely was considered as a ‘must-have’ application, the mobile version was only perceived as a ‘nice-to-have’ application and a complement to text mes¬saging (SMS. Almost one year later, in April 2008, Ericsson Research performed a short qualita¬tive follow-up study with the same set of respondents to un¬derstand if and how the mobile MSN Messenger usage had changed. The results actually revealed that none of the re¬spondents used mobile MSN Messenger anymore as the application no longer was free of charge. On a general level, the study highlights important considera¬tions when intro¬ducing computer-based concepts and Internet services in a mo¬bile environment.

Geodesy at Mercury with MESSENGER

Science.gov (United States)

Smith, David E.; Zuber, Maria t.; Peale, Stanley J.; Phillips, Roger J.; Solomon, Sean C.

2006-01-01

In 2011 the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft will enter Mercury orbit and begin the mapping phase of the mission. As part of its science objectives the MESSENGER mission will determine the shape and gravity field of Mercury. These observations will enable the topography and the crustal thickness to be derived for the planet and will determine the small libration of the planet about its axis, the latter critical to constraining the state of the core. These measurements require very precise positioning of the MESSENGER spacecraft in its eccentric orbit, which has a periapsis altitude as low as 200 km, an apoapsis altitude near 15,000 km, and a closest approach to the surface varying from latitude 60 to about 70 N. The X-band tracking of MESSENGER and the laser altimetry are the primary data that will be used to measure the planetary shape and gravity field. The laser altimeter, which has an expected range of 1000 to 1200 km, is expected to provide significant data only over the northern hemisphere because of MESSENGER's eccentric orbit. For the southern hemisphere, radio occultation measurements obtained as the spacecraft passes behind the planet as seen from Earth and images obtained with the imaging system will be used to provide the long-wavelength shape of the planet. Gravity, derived from the tracking data, will also have greater resolution in the northern hemisphere, but full global models for both topography and gravity will be obtained at low harmonic order and degree. The limiting factor for both gravity and topography is expected to be knowledge of the spacecraft location. Present estimations are that in a combined tracking, altimetry, and occultation solution the spacecraft position uncertainty is likely to be of order 10 m. This accuracy should be adequate for establishing an initial geodetic coordinate system for Mercury that will enable positioning of imaged features on the surface, determination of

MESSENGER'S First and Second Flybys of Mercury

Science.gov (United States)

Slavin, James A.

2009-01-01

The MESSENGER mission to Mercury offers our first opportunity to explore this planet's miniature magnetosphere since Mariner 10's brief fly-bys in 1974-5. The magnetosphere of Mercury is the smallest in the solar system with its magnetic field typically standing off the solar wind only approximately 1000 km above the surface. An overview of the MESSENGER mission and its January 14th and October 6th, 2008 close flybys of Mercury will be provided. Primary science objectives and the science instrumentation will be described. Initial results from MESSENGER will be discussed with an emphasis on the magnetic field and charged particle measurements.

Selective turn-on fluorescent probes for imaging hydrogen sulfide in living cells.

Science.gov (United States)

Montoya, Leticia A; Pluth, Michael D

2012-05-16

Hydrogen sulfide (H(2)S) is an important biological messenger but few biologically-compatible methods are available for its detection. Here we report two bright fluorescent probes that are selective for H(2)S over cysteine, glutathione and other reactive sulfur, nitrogen, and oxygen species. Both probes are demonstrated to detect H(2)S in live cells. This journal is © The Royal Society of Chemistry 2012

Evolving Coronal Holes and Interplanetary Erupting Stream ...

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... Coronal holes and interplanetary disturbances are important aspects of the physics of the Sun and heliosphere. Interplanetary disturbances are identified as an increase in the density turbulence compared with the ambient solar wind. Erupting stream disturbances are transient large-scale structures of ...

Doppler frequency in interplanetary radar and general relativity

Science.gov (United States)

Mcvittie, G. C.

1972-01-01

The change of frequency of an interplanetary radar signal sent from the earth to another planet or to a space probe is worked out according to general relativity. The Schwarzschild spacetime is employed and its null geodesics control the motion of the signals. Exact Doppler frequency formulas are derived for one-way and two-way radar in terms of an arbitrary Schwarzschild radial coordinate. A reduction to the special relativity case is used to interpret the formulas in terms of the relative radial velocity of emitter and target. The general relativity corrections are worked out approximately for each of three possible Schwarzschild radial coordinates, and a numerical example is given. The amount of the correction is different according as one or the other of the Schwarzschild coordinates is identified with the radius vector deduced from classical celestial mechanics. The identification problem is discussed.

MESSENGER at Mercury: Early Orbital Operations

Science.gov (United States)

McNutt, Ralph L., Jr; Solomon, Sean C.; Bedini, Peter D.; Anderson, Brian J.; Blewett, David T.; Evans, Larry G.; Gold, Robert E.; Krimigis, Stamatios M.; Murchie, Scott L.; Nittler, Larry R.;

MESSENGER Searches for Less Abundant or Weakly Emitting Species in Mercury's Exosphere

Science.gov (United States)

Vervack, Ronald J., Jr.; McClintock, William E.; Killen, Rosemary M.; Sprague, Ann L.; Burger, Matthew H.; Merkel, Aimee W.; Sarantos, Menelaos

2011-01-01

Mercury's exosphere is composed of material that originates at the planet's surface, whether that material is native or delivered by the solar wind and micrometeoroids. Many exospheric species have been detected by remote sensing, including H and He by Mariner 10, Na, K, and Ca by ground-based observations, and H, Na, Ca, Mg, and Ca+ by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. Other exospheric species, including Fe, AI, Si, 0, S, Mn, CI, Ti, OH, and their ions, are expected to be present on the basis of MESSENGER surface measurements and models of Mercury's surface chemistry. Here we report on searches for these species made with the Ultraviolet and Visible Spectrometer (UVVS) channel of the Mercury Atmospheric and Surface Composition Spectrometer (MASCS). No obvious signatures of the listed species have yet been observed in Mercury's exosphere by the UVVS as of this writing. It is possible that detections are elusive because the optimum regions of the exosphere have not been sampled. The Sun-avoidance constraints on MESSENGER place tight limits on instrument boresight directions, and some regions are probed infrequently. If there are strong spatial gradients in the distribution of weakly emitting species, a high-resolution sampling of specific regions may be required to detect them. Summing spectra over time will also aid in the ability to detect weaker emission. Observations to date nonetheless permit strong upper limits to be placed on the abundances of many undetected species, in some cases as functions of time and space. As those limits are lowered with time, the absence of detections can provide insight into surface composition and the potential source mechanisms of exospheric material.

Study of Travelling Interplanetary Phenomena Report

Science.gov (United States)

Dryer, Murray

1987-09-01

Scientific progress on the topic of energy, mass, and momentum transport from the Sun into the heliosphere is contingent upon interdisciplinary and international cooperative efforts on the part of many workers. Summarized here is a report of some highlights of research carried out during the SMY/SMA by the STIP (Study of Travelling Interplanetary Phenomena) Project that included solar and interplanetary scientists around the world. These highlights are concerned with coronal mass ejections from solar flares or erupting prominences (sometimes together); their large-scale consequences in interplanetary space (such as shocks and magnetic 'bubbles'); and energetic particles and their relationship to these large-scale structures. It is concluded that future progress is contingent upon similar international programs assisted by real-time (or near-real-time) warnings of solar activity by cooperating agencies along the lines experienced during the SMY/SMA.

Interplanetary matter

International Nuclear Information System (INIS)

Ceplecha, Z.; Pecina, P.

1987-01-01

Of the total number of 57 presented papers 56 have been submitted to INIS. One paper was out of INIS scope. List of sessions (in brackets is the number of papers presented in the respective session and incorporated in the INIS): Preface (2), Comets (17), Asteroids (7), Meteors (19), Interplanetary dust (9), Other bodies (2). (Z.S.). 155 figs., 68 tabs., 1140 refs

Messenger Observations of Mercury's Bow Shock and Magnetopause

Science.gov (United States)

Slavin J. A.; Acuna, M. H.; Anderson, B. J.; Benna, M.; Gloeckler, G.; Krimigis, S. M.; Raines, M.; Schriver, D.; Travnicek, P.; Zurbuchen, T. H.

2008-01-01

The MESSENGER spacecraft made the first of three flybys of Mercury on January 14.2008 (1). New observations of solar wind interaction with Mercury were made with MESSENGER'S Magnetometer (MAG) (2.3) and Energetic Particle and Plasma Spectrometer (EPPS) - composed of the Energetic Particle Spectrometer (EPS) and Fast Imaging Plasma Spectrometer (FIPS) (3,4). These MESSENGER observations show that Mercury's magnetosphere has a large-scale structure that is distinctly Earth-like, but it is immersed in a comet-like cloud of planetary ions [5]. Fig. 1 provides a schematic view of the coupled solar wind - magnetosphere - neutral atmosphere - solid planet system at Mercury.

Bacterial nucleotide-based second messengers.

Science.gov (United States)

Pesavento, Christina; Hengge, Regine

2009-04-01

In all domains of life nucleotide-based second messengers transduce signals originating from changes in the environment or in intracellular conditions into appropriate cellular responses. In prokaryotes cyclic di-GMP has emerged as an important and ubiquitous second messenger regulating bacterial life-style transitions relevant for biofilm formation, virulence, and many other bacterial functions. This review describes similarities and differences in the architecture of the cAMP, (p)ppGpp, and c-di-GMP signaling systems and their underlying signaling principles. Moreover, recent advances in c-di-GMP-mediated signaling will be presented and the integration of c-di-GMP signaling with other nucleotide-based signaling systems will be discussed.

Cosmic Microwave Background Mapmaking with a Messenger Field

Science.gov (United States)

Huffenberger, Kevin M.; Næss, Sigurd K.

2018-01-01

We apply a messenger field method to solve the linear minimum-variance mapmaking equation in the context of Cosmic Microwave Background (CMB) observations. In simulations, the method produces sky maps that converge significantly faster than those from a conjugate gradient descent algorithm with a diagonal preconditioner, even though the computational cost per iteration is similar. The messenger method recovers large scales in the map better than conjugate gradient descent, and yields a lower overall χ2. In the single, pencil beam approximation, each iteration of the messenger mapmaking procedure produces an unbiased map, and the iterations become more optimal as they proceed. A variant of the method can handle differential data or perform deconvolution mapmaking. The messenger method requires no preconditioner, but a high-quality solution needs a cooling parameter to control the convergence. We study the convergence properties of this new method and discuss how the algorithm is feasible for the large data sets of current and future CMB experiments.

"Driverless" Shocks in the Interplanetary Medium

Science.gov (United States)

Gopalswamy, N.; Kaiser, M. L.; Lara, A.

1999-01-01

Many interplanetary shocks have been detected without an obvious driver behind them. These shocks have been thought to be either blast waves from solar flares or shocks due to sudden increase in solar wind speed caused by interactions between large scale open and closed field lines of the Sun. We investigated this problem using a set of interplanetary shock detected {\\it in situ} by the Wind space craft and tracing their solar origins using low frequency radio data obtained by the Wind/WAVES experiment. For each of these "driverless shocks" we could find a unique coronal mass ejections (CME) event observed by the SOHO (Solar and Heliospheric Observatory) coronagraphs. We also found that these CMEs were ejected at large angles from the Sun-Earth line. It appears that the "driverless shocks" are actually driver shocks, but the drivers were not intercepted by the spacecraft. We conclude that the interplanetary shocks are much more extended than the driving CMEs.

Multifrequency techniques for studying interplanetary scintillations

International Nuclear Information System (INIS)

Woo, R.

1975-01-01

Rytov's approximation or the method of smooth perturbations is utilized to derive the temporal frequency spectra of the amplitude and phase fluctuations of multifrequency plane and spherical waves propagating in the interplanetary medium and solar corona. It is shown that multifrequency observations of interplanetary scintillations using either compact radio stars or spacecraft radio signals are desirable because the correlation of the multifrequency waves yields additional independent measurements of the solar wind and turbulence. Measurements of phase fluctuations are also desirable because, unlike amplitude fluctuations, they provide information on the full range of scale sizes for the electron density fluctuations. It is shown that a coherent dual-frequency radio system is particularly useful in making such measurements. In addition to providing a means for interpreting observations of multifrequency interplanetary scintillations, the analysis is also essential for estimating the effects of solar corona turbulence on the communications and navigation of a spacecraft whose line-of-sight path passes close to the Sun

Dynamics of interplanetary dust grains

International Nuclear Information System (INIS)

Lamy, P.L.

1975-01-01

The interaction of spherical grains of various materials-three silicates (quartz, obsidian and andesite), water-ice and iron - whose radii lie in the micronic and submicronic range with the interplanetary medium is solved. This includes: the interaction with the solar radiation field which is solved using Mie scattering theory and taking into account the precise dependence of the optical properties of the five materials upon wavelength; the interaction with the solar wind: corpuscular tangential drag is found to be always important and may even be larger than the Poynting-Robertson drag; the interaction with the interplanetary magnetic field is investigated in terms of a diffusion or random walk through a series of electromagnetic scatterings, leading to a Chapman-Komolgorov equation (i.e., a generalized Liouville equation). Numerical results are presented for these interactions spanning the entire solar system with circularity of elliptical orbits, direct or retrograde, with grains of various materials and sizes and giving -probably for the first time - a clear global picture of the interaction of dust grains with the interplanetary medium. The dynamics of the grains is then investigated using the theory of general perturbations and the numerical integration of trajectories of circum-solar grains

Messenger RNA 3' end formation in plants.

Science.gov (United States)

Hunt, A G

2008-01-01

Messenger RNA 3' end formation is an integral step in the process that gives rise to mature, translated messenger RNAs in eukaryotes. With this step, a pre-messenger RNA is processed and polyadenylated, giving rise to a mature mRNA bearing the characteristic poly(A) tract. The poly(A) tract is a fundamental feature of mRNAs, participating in the process of translation initiation and being the focus of control mechanisms that define the lifetime of mRNAs. Thus messenger RNA 3' end formation impacts two steps in mRNA biogenesis and function. Moreover, mRNA 3' end formation is something of a bridge that integrates numerous other steps in mRNA biogenesis and function. While the process is essential for the expression of most genes, it is also one that is subject to various forms of regulation, such that both quantitative and qualitative aspects of gene expression may be modulated via the polyadenylation complex. In this review, the current status of understanding of mRNA 3' end formation in plants is discussed. In particular, the nature of mRNA 3' ends in plants is reviewed, as are recent studies that are beginning to yield insight into the functioning and regulation of plant polyadenylation factor subunits.

International Launch Vehicle Selection for Interplanetary Travel

Science.gov (United States)

Ferrone, Kristine; Nguyen, Lori T.

2010-01-01

In developing a mission strategy for interplanetary travel, the first step is to consider launch capabilities which provide the basis for fundamental parameters of the mission. This investigation focuses on the numerous launch vehicles of various characteristics available and in development internationally with respect to upmass, launch site, payload shroud size, fuel type, cost, and launch frequency. This presentation will describe launch vehicles available and in development worldwide, then carefully detail a selection process for choosing appropriate vehicles for interplanetary missions focusing on international collaboration, risk management, and minimization of cost. The vehicles that fit the established criteria will be discussed in detail with emphasis on the specifications and limitations related to interplanetary travel. The final menu of options will include recommendations for overall mission design and strategy.

Intermittent character of interplanetary magnetic field fluctuations

International Nuclear Information System (INIS)

Bruno, Roberto; Carbone, Vincenzo; Chapman, Sandra; Hnat, Bogdan; Noullez, Alain; Sorriso-Valvo, Luca

2007-01-01

Interplanetary magnetic field magnitude fluctuations are notoriously more intermittent than velocity fluctuations in both fast and slow wind. This behavior has been interpreted in terms of the anomalous scaling observed in passive scalars in fully developed hydrodynamic turbulence. In this paper, the strong intermittent nature of the interplanetary magnetic field is briefly discussed comparing results performed during different phases of the solar cycle. The scaling properties of the interplanetary magnetic field magnitude show solar cycle variation that can be distinguished in the scaling exponents revealed by structure functions. The scaling exponents observed around the solar maximum coincide, within the errors, to those measured for passive scalars in hydrodynamic turbulence. However, it is also found that the values are not universal in the sense that the solar cycle variation may be reflected in dependence on the structure of the velocity field

A Common Probe Design for Multiple Planetary Destinations

Science.gov (United States)

Hwang, H. H.; Allen, G. A., Jr.; Alunni, A. I.; Amato, M. J.; Atkinson, D. H.; Bienstock, B. J.; Cruz, J. R.; Dillman, R. A.; Cianciolo, A. D.; Elliott, J. O.;

Holographic gauge mediation via strongly coupled messengers

International Nuclear Information System (INIS)

McGuirk, Paul; Shiu, Gary; Sumitomo, Yoske

2010-01-01

We consider a relative of semidirect gauge mediation where the hidden sector exists at large 't Hooft coupling. Such scenarios can be difficult to describe using perturbative field theory methods but may fall into the class of holographic gauge mediation scenarios, meaning that they are amenable to the techniques of gauge/gravity duality. We use a recently found gravity solution to examine one such case, where the hidden sector is a cascading gauge theory resulting in a confinement scale not much smaller than the messenger mass. In the original construction of holographic gauge mediation, as in other examples of semidirect gauge mediation at strong coupling, the primary contributions to visible sector soft terms come from weakly coupled messenger mesons. In contrast to these examples, we describe the dual of a gauge theory where there are significant contributions from scales in which the strongly coupled messenger quarks are the effective degrees of freedom. In this regime, the visible sector gaugino mass can be calculated entirely from holography.

Variations of interplanetary parameters and cosmic-ray intensities

International Nuclear Information System (INIS)

Geranios, A.

1980-01-01

Observations of cosmic ray intensity depressions by earth bound neutron monitors and measurements of interplanetary parameter's variations aboard geocentric satellites in the period January 1972-July 1974 are analysed and grouped according to their correlation among them. From this analysis of about 30 cases it came out that the majority of the depressions correlates with the average propagation speed of interplanetary shocks as well as with the amplitude of the interplanetary magnetic field after the eruption of a solar flare. About one fourth of the events correlates with corotating fast solar wind streams. As the recovery time of the shock-related depressions depends strongly on the heliographic longitude of the causitive solar flare, it seems that the cosmic ray modulation region has a corotative-like feature. (Auth.)

Sector boundary distortion in the interplanetary medium

International Nuclear Information System (INIS)

Suess, S.T.; Feynman, J.

1977-01-01

We address the theoretical problem of the effect of a solar wind meridional velocity gradient on the orientation, or tipping, of a line embedded within the interplanetary plasma. We find that rotations of from 30degree to 75degree, between 1.5 solar radii and I AU, are produced when observed values for the solar wind velocity and its meridional gradient are used. This is not a small effect, nor is it difficult to calculate: it is a natural consequence of any meridional velocity gradient in the interplanetary medium. In relating this result to observed sector boundaries we note that the latitude dependence of the width of interplanetary magnetic sectors (dominant polarity or Rosenberg-Coleman effect) implies that sector boundaries at I AU are generally inclined at an angle of from 10degree to 20degree to the solar equatorial plane. Conversely, studies of photospheric magnetic fields have led to the conclusion that sector boundaries near the sun are, on the average, at large angles (approx.90degree) to the solar equatorial plane. If the dominant polarity effect were to be produced by rotation in the interplanetary medium, the sign of the solar wind meridional velocity gradient must not change at the equator, but the gradient does have to change sign for +/- boundary crossings in comparison to -/+ boundary crossings

Observations of energetic particles in the near and far interplanetary medium

International Nuclear Information System (INIS)

Gloeckler, G.

1979-01-01

Recent experimental results suggest that acceleration of particles to energies as high as 30 MeV/nucleon is commonplace in the interplanetary medium beyond several AU, and that most of the > or approx. =10 MeV/nucleon particles observed near earth, especially at solar minimum, are predominantly interplanetary in origin. We review experimental observations of the anomalous ''cosmic-ray'' component and of corotating particle streams with an emphasis on the composition of these interplanetary particles. These direct observations, although still rudimentary, are already providing constraints necessary for developing realistic theoretical descriptions of interplanetary acceleration mechanisms and should thus help us to understand similar processes in other astrophysical objects

MESSENGER MERCURY RSS/MLA LEVEL 5 DERIVED DATA V1.0

Data.gov (United States)

National Aeronautics and Space Administration — This data set contains archival results from radio science investigations conducted during the MESSENGER mission. Radio measurements were made using the MESSENGER...

Interplanetary medium and geomagnetic activity after compact flare triplets 1966-1981

International Nuclear Information System (INIS)

Ivanov, K.G.; Mikerina, N.V.; Pavlov, P.P.

1986-01-01

The interplanetary medium state and geomagnetic activity when the Earth is getting into this or that interplanetary disturbance zone after flare triplets, i.e. trains of three solar flares out of an active zone, are considered. There are the following conditionally differentiated zones in the interplanetary disturbance configuration: a forbidden (F), a perturbed (P) and a normal (N) zones of interplanetary disturbance. The interplanetary medium disturbances and geomagnetic activity after trains of three flares of class 2 and higher out of one of active zones depend on the following factors: the magnetic axis orientation of a bipolar group of active zone spots appeared after flares, time interval between the first and second flares in the train, flare intensity. The conditions of maximum disturbance occurrence pointed out. The interplanetary and geomagnetic disturbance intensity in the N zone is higher than that of the F and P zones (i.e. in the proximity of the great circle planes passing through the flares parallel with tha active zone magnetic axes), and it is higher after quasicompact rather than after compact triplets (i.e. it considerably grows when passing over the critical value of the time interval betwenn the first and second triplet flares, τ 12 =16 h)

Comparison of S3-3 polar cap potential drops with the interplanetary magnetic field and models of magnetopause reconnection

International Nuclear Information System (INIS)

Wygant, J.R.; Torbert, R.B.; Mozer, F.S.

1983-01-01

Measurements of the cross polar cap electric potential, by the double probe electric field experiment aboard S3-3, from 55 orbits in the dawn-dusk plane are compared with the reconnection electric fields predicted by a variety of models, both theoretical and experimental. The purpose of these comparisons is to understand the extent to which nonreconnection contributes to the polar cap potential must be included, to determine the time response of the polar cap potential to time varying reconnection rates, and to determine the efficiency and saturation levels of the reconnection process. It is found that (1) After several hours of northward interplanetary magnetic field, the cross polar cap potential declines to progressively lower values than those after 1 hour of northward interplanetary magnetic field. This suggests that it requires several hours for the ionospheric polar cap potential to respond to the ''turning off'' of ''turning down'' of the reconnection process. (2) The decay of the polar cap potential is used to demonstrate that contirubtions to the polar cap potential not associated with the reconnection process can be limited to less than 20 kV. It is shown that contributions to the polar cap potential that scale with the dynamic pressure of the solar wind are limited to less than 1 kV. (3) The cross polar cap electric potential is best predicted by a weighted sum of contributions from interplanetary magnetic field parameter over the 4 hours previous to the measurement. The weighting functions have the form of an exponential decay 2--3 hours with the strongest weight on interplanetary parameters over the 1 hour previous to the measurement

Some Metabolites Act as Second Messengers in Yeast Chronological Aging

Directory of Open Access Journals (Sweden)

Karamat Mohammad

2018-03-01

Full Text Available The concentrations of some key metabolic intermediates play essential roles in regulating the longevity of the chronologically aging yeast Saccharomyces cerevisiae. These key metabolites are detected by certain ligand-specific protein sensors that respond to concentration changes of the key metabolites by altering the efficiencies of longevity-defining cellular processes. The concentrations of the key metabolites that affect yeast chronological aging are controlled spatially and temporally. Here, we analyze mechanisms through which the spatiotemporal dynamics of changes in the concentrations of the key metabolites influence yeast chronological lifespan. Our analysis indicates that a distinct set of metabolites can act as second messengers that define the pace of yeast chronological aging. Molecules that can operate both as intermediates of yeast metabolism and as second messengers of yeast chronological aging include reduced nicotinamide adenine dinucleotide phosphate (NADPH, glycerol, trehalose, hydrogen peroxide, amino acids, sphingolipids, spermidine, hydrogen sulfide, acetic acid, ethanol, free fatty acids, and diacylglycerol. We discuss several properties that these second messengers of yeast chronological aging have in common with second messengers of signal transduction. We outline how these second messengers of yeast chronological aging elicit changes in cell functionality and viability in response to changes in the nutrient, energy, stress, and proliferation status of the cell.

How MESSENGER Meshes Simulations and Games with Citizen Science

Science.gov (United States)

Hirshon, B.; Chapman, C. R.; Edmonds, J.; Goldstein, J.; Hallau, K. G.; Solomon, S. C.; Vanhala, H.; Weir, H. M.; Messenger Education; Public Outreach (Epo) Team

2010-12-01

How MESSENGER Meshes Simulations and Games with Citizen Science In the film The Last Starfighter, an alien civilization grooms their future champion—a kid on Earth—using a video game. As he gains proficiency in the game, he masters the skills he needs to pilot a starship and save their civilization. The NASA MESSENGER Education and Public Outreach (EPO) Team is using the same tactic to train citizen scientists to help the Science Team explore the planet Mercury. We are building a new series of games that appear to be designed primarily for fun, but that guide players through a knowledge and skill set that they will need for future science missions in support of MESSENGER mission scientists. As players score points, they gain expertise. Once they achieve a sufficiently high score, they will be invited to become participants in Mercury Zoo, a new program being designed by Zooniverse. Zooniverse created Galaxy Zoo and Moon Zoo, programs that allow interested citizens to participate in the exploration and interpretation of galaxy and lunar data. Scientists use the citizen interpretations to further refine their exploration of the same data, thereby narrowing their focus and saving precious time. Mercury Zoo will be designed with input from the MESSENGER Science Team. This project will not only support the MESSENGER mission, but it will also add to the growing cadre of informed members of the public available to help with other citizen science projects—building on the concept that engaged, informed citizens can help scientists make new discoveries. The MESSENGER EPO Team comprises individuals from the American Association for the Advancement of Science (AAAS); Carnegie Academy for Science Education (CASE); Center for Educational Resources (CERES) at Montana State University (MSU) - Bozeman; National Center for Earth and Space Science Education (NCESSE); Johns Hopkins University Applied Physics Laboratory (JHU/APL); National Air and Space Museum (NASM); Science

Positive and negative sudden impulses caused by fast forward and reverse interplanetary shocks

Energy Technology Data Exchange (ETDEWEB)

Andrioli, Vania Fatima; Savian, Jairo Francisco, E-mail: vaniafatima@gmail.com, E-mail: savian@lacesm.ufsm.br [Space Science Laboratory of Santa Maria - LACESM/CT - UFSM, Universidade Federal de Santa Maria - UFSM, Centro Tecnologico, Santa Maria, RS (Brazil); Echer, Ezequiel, E-mail: eecher@dge.inpe.br [National Institute for Space Research - INPE - MCT, Sao Jose dos Campos, SP (Brazil); Schuch, Nelson Jorge, E-mail: njschuch@lacesm.ufsm.br [Southern Regional Space Research Center - CRSPE/INPE - MCT, Universidade Federal de Santa Maria - UFSM, Santa Maria, RS (Brazil)

2007-07-01

Fast forward interplanetary shocks (FFS) are characterized by positive jump in all interplanetary plasma parameters (solar wind speed, temperature and density) and interplanetary magnetic field. However the fast reverse interplanetary shocks (FRS) are characterized by negative jump in all mentioned parameters except solar wind speed. Observations show that FFS cause positive sudden impulses (SI) while FRS cause negative SI in the H-component of the geomagnetic field. In this work we investigate the SI caused by interplanetary shocks. We use the observed plasma parameters, upstream and downstream, to calculate the variation of dynamic pressure. We observe that the SI amplitude is larger for positive SI than for negative ones, as a consequence of the fact that FFS have larger dynamic pressure variations as compared to FRS. (author)

Nuclear Export of Messenger RNA

Directory of Open Access Journals (Sweden)

Jun Katahira

2015-03-01

Full Text Available Transport of messenger RNA (mRNA from the nucleus to the cytoplasm is an essential step of eukaryotic gene expression. In the cell nucleus, a precursor mRNA undergoes a series of processing steps, including capping at the 5' ends, splicing and cleavage/polyadenylation at the 3' ends. During this process, the mRNA associates with a wide variety of proteins, forming a messenger ribonucleoprotein (mRNP particle. Association with factors involved in nuclear export also occurs during transcription and processing, and thus nuclear export is fully integrated into mRNA maturation. The coupling between mRNA maturation and nuclear export is an important mechanism for providing only fully functional and competent mRNA to the cytoplasmic translational machinery, thereby ensuring accuracy and swiftness of gene expression. This review describes the molecular mechanism of nuclear mRNA export mediated by the principal transport factors, including Tap-p15 and the TREX complex.

Nuclear Export of Messenger RNA

Science.gov (United States)

Katahira, Jun

2015-01-01

Transport of messenger RNA (mRNA) from the nucleus to the cytoplasm is an essential step of eukaryotic gene expression. In the cell nucleus, a precursor mRNA undergoes a series of processing steps, including capping at the 5' ends, splicing and cleavage/polyadenylation at the 3' ends. During this process, the mRNA associates with a wide variety of proteins, forming a messenger ribonucleoprotein (mRNP) particle. Association with factors involved in nuclear export also occurs during transcription and processing, and thus nuclear export is fully integrated into mRNA maturation. The coupling between mRNA maturation and nuclear export is an important mechanism for providing only fully functional and competent mRNA to the cytoplasmic translational machinery, thereby ensuring accuracy and swiftness of gene expression. This review describes the molecular mechanism of nuclear mRNA export mediated by the principal transport factors, including Tap-p15 and the TREX complex. PMID:25836925

Heliomagnetic cycle of magneto-ionospheric and interplanetary activities

International Nuclear Information System (INIS)

Zaretskij, N.S.; Krymskij, P.F.; Maksimov, Ya.Ya.

1983-01-01

The difference in frequency distributions of geomagnetic- and ionospheric disturbance levels are revealed within generalized intervals: odd-even- and even-odd 11-year solar activity cycles. The interplanetary medium of the first half of the 20th cycle (before reversal of the general heliomagnetic field polarity) is characterized by the background vertical component of the interplanetary magnetic field (IMF) in the north direction, rather small variability of the interplanetary field and low solar wind velocity. The south field component, higher field dispersion and high-velocity corpuscular fluxes are characteristic of the second half of the cycle. The 22-year variation in the number of small and moderate values of the geomagnetic activity within the limits of the 20th cycle is satisfactorily described by the behaviour of the quantities of the corresponding values of the IMF north-south component, field variability and solar wind velocity

Particle acceleration by coronal and interplanetary shock waves

International Nuclear Information System (INIS)

Pesses, M.E.

1982-01-01

Utilizing many years of observation from deep space and near-earth spacecraft a theoretical understanding has evolved on how ions and electrons are accelerated in interplanetary shock waves. This understanding is now being applied to solar flare-induced shock waves propagating through the solar atmosphere. Such solar flare phenomena as gamma-ray line and neutron emissions, interplanetary energetic electron and ion events, and Type II and moving Type IV radio bursts appear understandable in terms of particle acceleration in shock waves

Relationships between interplanetary quantities and the global auroral electrojet index

International Nuclear Information System (INIS)

Meloni, A.; Wolfe, A.; Lanzerotti, L.J.

1982-01-01

We have studied, using linear cross correlation and multilinear regression analyses, statistical relations between the magnetospheric auroral electrojet intensity index AE and various parameters characterizing the interplanetary plasma and magnetic field. We also consider the recently proposed epsilon parameter as an independent variable. The analyses were carried out separately for twenty-eight days in mid 1975 and for each of five individual magnetic storm intervals that have been previously discussed extensively in the literature. We find that when the interplanetary data set is not distinguished as to the direction of the north-south component B/sub z/, the interplanetary electric field -VB/sub z/ carried to the front of the magnetosphere correlates with AE substantially better than does epsilon. Considering only data during which B/sub z/ is negative gives a slightly better correlation of epsilon with AE than of the electric field with AE. The correlations are valid for the specific storm periods as well as for the unrestricted twenty-eight days of data. Our results suggest that the physical processes involved in energy transfer to the nightside magnetosphere depend upon the direction of the north-south component of the interplanetary magnetic field: the interplanetary electric field plays an important role during northward B/sub z/ and the epsilon parameter and the electric field both provide an indication of energy transfer and substorm activity during southward B/sub z/

The characteristic response of whistler mode waves to interplanetary shocks

Science.gov (United States)

Yue, C.; Chen, L.; Bortnik, J.; Ma, Q.; Thorne, R. M.; Angelopoulos, V.; Li, J.; An, X.; Zhou, C.

2017-12-01

Magnetospheric whistler mode waves play a key role in regulating the dynamics of the electron radiation belts. Recent satellite observations indicate a significant influence of interplanetary (IP) shocks on whistler mode wave power in the inner magnetosphere. In this study, we statistically investigate the response of whistler mode chorus and plasmaspheric hiss to IP shocks based on Van Allen Probes and THEMIS satellite observations. Immediately after the IP shock arrival, chorus wave power is usually intensified, often at dawn, while plasmaspheric hiss wave power predominantly decreases near the dayside but intensifies near the nightside. We conclude that chorus wave intensification outside the plasmasphere is probably associated with the suprathermal electron flux enhancement caused by the IP shock. On the other hand, the solar wind dynamic pressure increase changes the magnetic field configuration to favor ray penetration into the nightside and promote ray refraction away from the dayside, explaining the magnetic local time (MLT) dependent responses of plasmaspheric hiss waves following IP shock arrivals.

Messengers of the universe: Session IV Summary

International Nuclear Information System (INIS)

Bernardini, Elisa; Serpico, Pasquale Dario

2013-01-01

Being stable, light and neutral weakly interacting particles, neutrinos are ideal messengers of the deep universe and a channel of choice in particular to explore the very high energy Galactic and Extragalactic sky, playing a synergic role most notably with gamma-ray observations. Neutrino astronomy—long after the SN1987A detection in the MeV range—is mature enough for decisive tests of astrophysical paradigms. Its current status constitutes one of the two big pillars of the “Messengers of the universe” session of the Neutrino Oscillation Workshop 2012. Neutrinos may also play a role in some cosmological contexts, such as the early universe and the dark matter problem. We review both aspects in this session summary report

On an effect of the interplanetary magnetic field sector structure on the upper Earth's ionosphere

International Nuclear Information System (INIS)

Kolomijtsev, O.P.; Livshits, M.A.; Soboleva, T.N.

1985-01-01

According to the data from vertical probing stations, changes are studied in the critical frequency and height of the ionosphere F2 layer after the Earth crosses the boundaries of the interplanetary magnetic field (IMF) sectors in the periods of equinox during decreases in the solar activity. A reversal of the IMF sign causes ionospheric effects, which in some cases are comparable, as to the value, with the effects observed in the presence of flares and strong geomagnetic perturbations. The IMF sector sign reversal is a key momentum, stimulating such changes in the Earth's magnetosphere state which result in the rearrangement of the ionosphere structure near the maximum of electron concentration on the planetary scale

Hydromagnetic waves, turbulence, and collisionless processes in the interplanetary medium

International Nuclear Information System (INIS)

Barnes, A.

1983-01-01

The solar wind does not flow quietly. It seethes and undulates, fluctuating on time scales that range from the solar rotation period down to fractions of milliseconds. Most of the power in interplanetary waves and turbulence lies at hydromagnetic scales. These fluctuations are normally of large amplitude, containing enough energy to affect solar and galactic cosmic rays, and may be the remnants of a coronal turbulence field powerful enough to play a major role in accelerating the solar wind itself. The origin and evolution of interplanetary hydromagnetic waves and turbulence, and their influence on the large-scale dynamics of the solar wind are among the most fundamental questions of solar-terrestrial physics. First hydrodynamic waves and turbulences in the interplanetary medium are discussed in two sections, respectively. Because the length and time scales for hydromagnetic fluctuations are very much smaller than the corresponding Coulomb collision scales of the plasma ions and electrons, the interplanetary variations are modelled as fluctuations in a magnetohydrodynamic fluid. In the last section, collisionless phenomena are discussed. They are of qualitative significance. (Auth.)

Interplanetary laser ranging - an emerging technology for planetary science missions

Science.gov (United States)

Dirkx, D.; Vermeersen, L. L. A.

2012-09-01

Interplanetary laser ranging (ILR) is an emerging technology for very high accuracy distance determination between Earth-based stations and spacecraft or landers at interplanetary distances. It has evolved from laser ranging to Earth-orbiting satellites, modified with active laser transceiver systems at both ends of the link instead of the passive space-based retroreflectors. It has been estimated that this technology can be used for mm- to cm-level accuracy range determination at interplanetary distances [2, 7]. Work is being performed in the ESPaCE project [6] to evaluate in detail the potential and limitations of this technology by means of bottom-up laser link simulation, allowing for a reliable performance estimate from mission architecture and hardware characteristics.

Evolution of coronal and interplanetary magnetic fields

International Nuclear Information System (INIS)

Levine, R.H.

1980-01-01

Numerous studies have provided the detailed information necessary for a substantive synthesis of the empirical relation between the magnetic field of the sun and the structure of the interplanetary field. The author points out the latest techniques and studies of the global solar magnetic field and its relation to the interplanetary field. The potential to overcome most of the limitations of present methods of analysis exists in techniques of modelling the coronal magnetic field using observed solar data. Such empirical models are, in principle, capable of establishing the connection between a given heliospheric point and its magnetically-connected photospheric point, as well as the physical basis for the connection. (Auth.)

Machine learning and evolutionary techniques in interplanetary trajectory design

OpenAIRE

Izzo, Dario; Sprague, Christopher; Tailor, Dharmesh

2018-01-01

After providing a brief historical overview on the synergies between artificial intelligence research, in the areas of evolutionary computations and machine learning, and the optimal design of interplanetary trajectories, we propose and study the use of deep artificial neural networks to represent, on-board, the optimal guidance profile of an interplanetary mission. The results, limited to the chosen test case of an Earth-Mars orbital transfer, extend the findings made previously for landing ...

On the solar origin of interplanetary disturbances observed in the vicinity of the Earth

Directory of Open Access Journals (Sweden)

N. Vilmer

Full Text Available The solar origin of 40 interplanetary disturbances observed in the vicinity of the Earth between January 1997 and June 1998 is investigated in this paper. Analysis starts with the establishment of a list of Interplanetary Mass Ejections or ICMEs (magnetic clouds, flux ropes and ejecta and of Interplanetary Shocks measured at WIND for the period for which we had previously investigated the coupling of the interplanetary medium with the terrestrial ionospheric response. A search for associated coronal mass ejections (CMEs observed by LASCO/SOHO is then performed, starting from an estimation of the transit time of the inter-planetary perturbation from the Sun to the Earth, assumed to be achieved at a constant speed (i.e. the speed measured at 1 AU. EIT/SOHO and Nançay Radioheliograph (NRH observations are also used as proxies in this identification for the cases when LASCO observations do not allow one to firmly establish the association. The last part of the analysis concerns the identification of the solar source of the CMEs, performed using a large set of solar observations from X-ray to radio wavelengths. In the present study, this association is based on a careful examination of many data sets (EIT, NRH and H images and not on the use of catalogs and of Solar Geophysical Data reports. An association between inter-planetary disturbances and LASCO/CMEs or proxies on the disk is found for 36 interplanetary events. For 32 events, the solar source of activity can also be identified. A large proportion of cases is found to be associated with a flare signature in an active region, not excluding of course the involvement of a filament. Conclusions are finally drawn on the propagation of the disturbances in the interplanetary medium, the preferential association of disturbances detected close to the Earth’s orbit with halos or wide CMEs and the location on the solar disk of solar sources of the interplanetary disturbances during that period

Geomagnetic response of interplanetary coronal mass ejections in the Earth's magnetosphere

Science.gov (United States)

Badruddin; Mustajab, F.; Derouich, M.

2018-05-01

A coronal mass ejections (CME) is the huge mass of plasma with embedded magnetic field ejected abruptly from the Sun. These CMEs propagate into interplanetary space with different speed. Some of them hit the Earth's magnetosphere and create many types of disturbances; one of them is the disturbance in the geomagnetic field. Individual geomagnetic disturbances differ not only in their magnitudes, but the nature of disturbance is also different. It is, therefore, desirable to understand these differences not only to understand the physics of geomagnetic disturbances but also to understand the properties of solar/interplanetary structures producing these disturbances of different magnitude and nature. In this work, we use the spacecraft measurements of CMEs with distinct magnetic properties propagating in the interplanetary space and generating disturbances of different levels and nature. We utilize their distinct plasma and field properties to search for the interplanetary parameter(s) playing important role in influencing the geomagnetic response of different coronal mass ejections.

Criteria of interplanetary parameters causing intense magnetic storms (Dsub(st) < -100 nT)

International Nuclear Information System (INIS)

Gonzalez, W.D.; Tsurutani, B.T.

1987-01-01

Ten intense magnetic storms (Dsub(st) 5 mV m -1 , that last for intervals > 3 h. Because we find a one-to-one relationship between these interplanetary events and intense storms, we suggest that these criteria can, in the future, be used as predictors of intense storms by an interplanetary monitor such as ISEE-3. The close proximity of the Bsub(z) events and magnetic storms to the onset of high speed streams or density enhancement events is in sharp contrast to interplanetary Alfven waves and HILDCAA events previously reported and thus the two interplanetary features and corresponding geomagnetic responses can be thought of as being complementary in nature. An examination of opposite polarity (northward) Bsub(z) events with the same criteria shows that their occurrence is similar both in number as well as in their relationship to interplanetary disturbances, and that they lead to low levels of geomagnetic activity. (author)

GENESIS OF INTERPLANETARY INTERMITTENT TURBULENCE: A CASE STUDY OF ROPE–ROPE MAGNETIC RECONNECTION

Energy Technology Data Exchange (ETDEWEB)

Chian, Abraham C.-L.; Loew, Murray H. [Department of Biomedical Engineering, George Washington University, Washington, DC 20052 (United States); Feng, Heng Q. [Institute of Space Physics, Luoyang Normal University, Luoyang (China); Hu, Qiang [Department of Space Science and CSPAR, University of Alabama in Huntsville, Huntsville, AL 35805 (United States); Miranda, Rodrigo A. [UnB-Gama Campus, and Plasma Physics Laboratory, Institute of Physics, University of Brasília (UnB), Brasília DF 70910-900 (Brazil); Muñoz, Pablo R. [Department of Physics and Astronomy, University of La Serena, Av. Juan Cisternas 1200, La Serena (Chile); Sibeck, David G. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Wu, De J., E-mail: abraham.chian@gmail.com [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

2016-12-01

In a recent paper, the relation between current sheet, magnetic reconnection, and turbulence at the leading edge of an interplanetary coronal mass ejection was studied. We report here the observation of magnetic reconnection at the interface region of two interplanetary magnetic flux ropes. The front and rear boundary layers of three interplanetary magnetic flux ropes are identified, and the structures of magnetic flux ropes are reconstructed by the Grad–Shafranov method. A quantitative analysis of the reconnection condition and the degree of intermittency reveals that rope–rope magnetic reconnection is the most likely site for genesis of interplanetary intermittency turbulence in this event. The dynamic pressure pulse resulting from this reconnection triggers the onset of a geomagnetic storm.

Study of interplanetary hydrogen from Lyman alpha emission and absorption determination

International Nuclear Information System (INIS)

Cazes, Serge.

1979-09-01

The purpose of the work submitted in this paper is to contribute to the study of interplanetary hydrogen from Lyman alpha emission and absorption measurements, carried out on board the D2A, OSO-8 and Copernicus satellites. This study, which was undertaken from the D2A satellite, moved us to study the interplanetary environment as from observations made from the following experiments placed on board the OSO-8 and Copernicus satellites. The experiment set up on board the OSO-8 satellite made it possible to obtain the profile of the solar alpha Lyman emission. An absorption profile was observed for the first time on these profiles and this made it possible to attribute them to interplanetary hydrogen and enabled us to make a direct and local determination of the solar ionization rate. - The spectrometer set up on board Copernicus made it possible to obtain the emission spectrum of the interplanetary environment at the same time as the geocorona. The overall velocity of the interplanetary environment was deduced from the Doppler shift between the two spectra. In the first part, the principle of the REA and POLAR experiments is recalled but only the REA experiment is described in detail, particularly the problems arising from the construction and calibration of the cell. In the second part, a study of the interplanetary environment made from the D2A determinations is presented in synthesized form. On the other hand, the study to which theses initial results led us is presented in detail. Finally, in the third part, the results obtained by means of the OSO-8 and Copernicus satellites are given [fr

Coronal and interplanetary propagation, interplanetary acceleration, cosmic-ray observations by deep space network and anomalous component

International Nuclear Information System (INIS)

Ng, C.K.

1986-01-01

The purpose is to provide an overview of the contributions presented in sessions SH3, SH1.5, SH4.6 and SH4.7 of the 19th International Cosmic Ray Conference. These contributed papers indicate that steady progress continues to be made in both the observational and the theoretical aspects of the transport and acceleration of energetic charged particles in the heliosphere. Studies of solar and interplanetary particles have placed emphasis on particle directional distributions in relation to pitch-angle scattering and magnetic focusing, on the rigidity and spatial dependence of the mean free path, and on new propagation regimes in the inner and outer heliosphere. Coronal propagation appears in need of correlative multi-spacecraft studies in association with detailed observation of the flare process and coronal magnetic structures. Interplanetary acceleration has now gone into a consolidation phase, with theories being worked out in detail and checked against observation

Coronal and interplanetary propagation, interplanetary acceleration, cosmic-ray observations by deep space network and anomalous component

Science.gov (United States)

Ng, C. K.

1986-01-01

The purpose is to provide an overview of the contributions presented in sessions SH3, SH1.5, SH4.6 and SH4.7 of the 19th International Cosmic Ray Conference. These contributed papers indicate that steady progress continues to be made in both the observational and the theoretical aspects of the transport and acceleration of energetic charged particles in the heliosphere. Studies of solar and interplanetary particles have placed emphasis on particle directional distributions in relation to pitch-angle scattering and magnetic focusing, on the rigidity and spatial dependence of the mean free path, and on new propagation regimes in the inner and outer heliosphere. Coronal propagation appears in need of correlative multi-spacecraft studies in association with detailed observation of the flare process and coronal magnetic structures. Interplanetary acceleration has now gone into a consolidation phase, with theories being worked out in detail and checked against observation.

Modelling interplanetary CMEs using magnetohydrodynamic simulations

Directory of Open Access Journals (Sweden)

P. J. Cargill

Full Text Available The dynamics of Interplanetary Coronal Mass Ejections (ICMEs are discussed from the viewpoint of numerical modelling. Hydrodynamic models are shown to give a good zero-order picture of the plasma properties of ICMEs, but they cannot model the important magnetic field effects. Results from MHD simulations are shown for a number of cases of interest. It is demonstrated that the strong interaction of the ICME with the solar wind leads to the ICME and solar wind velocities being close to each other at 1 AU, despite their having very different speeds near the Sun. It is also pointed out that this interaction leads to a distortion of the ICME geometry, making cylindrical symmetry a dubious assumption for the CME field at 1 AU. In the presence of a significant solar wind magnetic field, the magnetic fields of the ICME and solar wind can reconnect with each other, leading to an ICME that has solar wind-like field lines. This effect is especially important when an ICME with the right sense of rotation propagates down the heliospheric current sheet. It is also noted that a lack of knowledge of the coronal magnetic field makes such simulations of little use in space weather forecasts that require knowledge of the ICME magnetic field strength.

Key words. Interplanetary physics (interplanetary magnetic fields Solar physics, astrophysics, and astronomy (flares and mass ejections Space plasma physics (numerical simulation studies

A Statistical Study of Interplanetary Type II Bursts: STEREO Observations

Science.gov (United States)

Krupar, V.; Eastwood, J. P.; Magdalenic, J.; Gopalswamy, N.; Kruparova, O.; Szabo, A.

2017-12-01

Coronal mass ejections (CMEs) are the primary cause of the most severe and disruptive space weather events such as solar energetic particle (SEP) events and geomagnetic storms at Earth. Interplanetary type II bursts are generated via the plasma emission mechanism by energetic electrons accelerated at CME-driven shock waves and hence identify CMEs that potentially cause space weather impact. As CMEs propagate outward from the Sun, radio emissions are generated at progressively at lower frequencies corresponding to a decreasing ambient solar wind plasma density. We have performed a statistical study of 153 interplanetary type II bursts observed by the two STEREO spacecraft between March 2008 and August 2014. These events have been correlated with manually-identified CMEs contained in the Heliospheric Cataloguing, Analysis and Techniques Service (HELCATS) catalogue. Our results confirm that faster CMEs are more likely to produce interplanetary type II radio bursts. We have compared observed frequency drifts with white-light observations to estimate angular deviations of type II burst propagation directions from radial. We have found that interplanetary type II bursts preferably arise from CME flanks. Finally, we discuss a visibility of radio emissions in relation to the CME propagation direction.

Interplanetary Alfvenic fluctuations: A stochastic model

International Nuclear Information System (INIS)

Barnes, A.

1981-01-01

The strong alignment of the average directions of minimum magnetic variance and mean magnetic field in interplanetary Alfvenic fluctuations is inconsistent with the usual wave-propagation models. We investigate the concept of minimum variance for nonplanar Alfvenic fluctuations in which the field direction varies stochastically. It is found that the tendency of the minimum variance and mean field directions to be aligned may be purely a consequence of the randomness of the field direction. In particular, a well-defined direction of minimum variance does not imply that the fluctuations are necessarily planar. The fluctuation power spectrum is a power law for frequencies much higher than the inverse of the correlation time. The probability distribution of directions a randomly fluctuating field of constant magnitude is calculated. A new approach for observational studies of interplanetary fluctuations is suggested

On cryptographic security of end-to-end encrypted connections in WhatsApp and Telegram messengers

Directory of Open Access Journals (Sweden)

Sergey V. Zapechnikov

2017-11-01

Full Text Available The aim of this work is to analyze the available possibilities for improving secure messaging with end-to-end connections under conditions of external violator actions and distrusted service provider. We made a comparative analysis of cryptographic security mechanisms for two widely used messengers: Telegram and WhatsApp. It was found that Telegram is based on MTProto protocol, while WhatsApp is based on the alternative Signal protocol. We examine the specific features of messengers implementation associated with random number generation on the most popular Android mobile platform. It was shown that Signal has better security properties. It is used in several other popular messengers such as TextSecure, RedPhone, GoogleAllo, FacebookMessenger, Signal along with WhatsApp. A number of possible attacks on both messengers were analyzed in details. In particular, we demonstrate that the metadata are poorly protected in both messengers. Metadata security may be one of the goals for further studies.

3-D model of ICME in the interplanetary medium

Science.gov (United States)

Borgazzi, A.; Lara, A.; Niembro, T.

2011-12-01

We developed a method that describes with simply geometry the coordinates of intersection between the leading edge of an ICME and the position of an arbitrary satellite. When a fast CME is ejected from the Sun to the interplanetary space in most of the cases drives a shock. As the CME moves in the corona and later in the interplanetary space more material is stacking in the front and edges of the ejecta. In a first approximation, it is possible to assume the shape of these structures, the CME and the stacked material as a cone of revolution, (the ice-cream model [Schwenn et al., (2005)]). The interface may change due to the interaction of the structure and the non-shocked material in front of the ICME but the original shape of a cone of revolution is preserved. We assume, in a three dimensional geometry, an ice-cream cone shape for the ICME and apply an analytical model for its transport in the interplanetary medium. The goal of the present method is to give the time and the intersection coordinates between the leading edge of the ICME and any satellite that may be in the path of the ICME. With this information we can modelate the travel of the ICME in the interplanetary space using STEREO data.

Transceiver optics for interplanetary communications

Science.gov (United States)

Roberts, W. T.; Farr, W. H.; Rider, B.; Sampath, D.

2017-11-01

In-situ interplanetary science missions constantly push the spacecraft communications systems to support successively higher downlink rates. However, the highly restrictive mass and power constraints placed on interplanetary spacecraft significantly limit the desired bandwidth increases in going forward with current radio frequency (RF) technology. To overcome these limitations, we have evaluated the ability of free-space optical communications systems to make substantial gains in downlink bandwidth, while holding to the mass and power limits allocated to current state-of-the-art Ka-band communications systems. A primary component of such an optical communications system is the optical assembly, comprised of the optical support structure, optical elements, baffles and outer enclosure. We wish to estimate the total mass that such an optical assembly might require, and assess what form it might take. Finally, to ground this generalized study, we should produce a conceptual design, and use that to verify its ability to achieve the required downlink gain, estimate it's specific optical and opto-mechanical requirements, and evaluate the feasibility of producing the assembly.

Relation of geomagnetic activity index variations with parameters of interplanetary scintillations

International Nuclear Information System (INIS)

Vlasov, V.I.; Shishov, V.I.; Shishova, T.D.

1985-01-01

A correlation between the Asub(p)-index of geomagnetic activity, index of interplanetary scintillations and solar wind velocity, has been considered depending on the spatial position of the interplanetary plasma (IPP) regions under study. It is shown, that the scintillation index can be used to forecast the geomagnetic activity, whereas the solar wind velocity can not be used for the purpose. Heliolongitudinal dependence of geoeffectiveness of IPP sreading perturbations agrees well with their structure in the heliolongitudinal cross section (and, on the whole, with the angular structure and direction of IPP perturbation spread). To use interplanetary scintillations in forecasting the geomagnetic activity (on the level of correlation not below 0.5), the angular distance of the investigated IPP regions relative to the Sun-Earth line on the average should not exceed 30-40 deg. The time of delay between the moments of observation of variations in the scintillation index the time of passage of the corresponding heliocentric distances at an average rate of the interplanetary perturbation spread approximately 500 km/s

Messenger RNA surveillance: neutralizing natural nonsense

DEFF Research Database (Denmark)

Weischelfeldt, Joachim Lütken; Lykke-Andersen, Jens; Porse, Bo

2005-01-01

Messenger RNA transcripts that contain premature stop codons are degraded by a process termed nonsense-mediated mRNA decay (NMD). Although previously thought of as a pathway that rids the cell of non-functional mRNAs arising from mutations and processing errors, new research suggests a more general...

Mercury's Na Exosphere from MESSENGER Data

Science.gov (United States)

Killen, Rosemary M.; Burger, M. H.; Cassidy, T. A.; Sarantos, M.; Vervack, R. J.; McClintock, W. El; Merkel, A. W.; Sprague, A. L.; Solomon, S. C.

2012-01-01

MESSENGER entered orbit about Mercury on March 18, 2011. Since then, the Ultraviolet and Visible Spectrometer (UWS) channel of MESSENGER's Mercury Atmospheric and Surface Composition Spectrometer (MASCS) has been observing Mercury's exosphere nearly continuously. Daily measurements of Na brightness were fitted with non-uniform exospheric models. With Monte Carlo sampling we traced the trajectories of a representative number of test particles, generally one million per run per source process, until photoionization, escape from the gravitational well, or permanent sticking at the surface removed the atom from the simulation. Atoms were assumed to partially thermally accommodate on each encounter with the surface with accommodation coefficient 0.25. Runs for different assumed source processes are run separately, scaled and co-added. Once these model results were saved onto a 3D grid, we ran lines of sight from the MESSENGER spacecraft :0 infinity using the SPICE kernels and we computed brightness integrals. Note that only particles that contribute to the measurement can be constrained with our method. Atoms and molecules produced on the nightside must escape the shadow in order to scatter light if the excitation process is resonant-light scattering, as assumed here. The aggregate distribution of Na atoms fits a 1200 K gas, with a PSD distribution, along with a hotter component. Our models constrain the hot component, assumed to be impact vaporization, to be emitted with a 2500 K Maxwellian. Most orbits show a dawnside enhancement in the hot component broadly spread over the leading hemisphere. However, on some dates there is no dawn/dusk asymmetry. The portion of the hot/cold source appears to be highly variable.

Effects of the interplanetary conditions on the magnetic activity observed in the southern auroral zone

International Nuclear Information System (INIS)

Cazeneuve, H.A.; Tabocchini, H.

1981-01-01

The relationship between the interplanetary conditions and the magnetic activity recorded at Belgrano is examined. H-component magnetograms, rheometer records and the concurrent interplanetary data are used. It is found that the geomagnetic activity is generated by the combined effect of a variety of interplanetary conditions. The data distinctly show that each physical entity of the interplanetary medium has a specific and precise role in the development of active periods. The reversal of the IMF polarity appears to be the critical step in the generation of geomagnetic activity. (author)

Observations of interplanetary scintillation and their application to the space weather forecast

International Nuclear Information System (INIS)

Kojima, Masayoshi; Kakinuma, Takakiyo

1989-01-01

The interplanetary scintillation (IPS) method using natural radio sources can observe the solar wind near the sun and at high latitudes that have never been accessible to any spacecraft. Therefore, the IPS has been the most powerful method to observe the solar wind in three-dimensional space. Although the IPS method cannot predict when a flare will occur or when a filament will disappear, it can be used to forecast the propagation of interplanetary disturbances and to warn when they will attack the earth. Thus, the IPS method can be used to forecast recurrent interplanetary phenomena as well as transient phenomena. (author)

Generalized messengers of supersymmetry breaking and the sparticle mass spectrum

International Nuclear Information System (INIS)

Martin, S.P.

1997-01-01

We investigate the sparticle spectrum in models of gauge-mediated supersymmetry breaking. In these models, supersymmetry is spontaneously broken at an energy scale only a few orders of magnitude above the electroweak scale. The breakdown of supersymmetry is communicated to the standard model particles and their superpartners by open-quotes messengerclose quotes fields through their ordinary gauge interactions. We study the effects of a messenger sector in which the supersymmetry-violating F-term contributions to messenger scalar masses are comparable to the supersymmetry-preserving ones. We also argue that it is not particularly natural to restrict attention to models in which the messenger fields lie in complete SU(5) ground unified theory multiplets, and we identify a much larger class of viable models. Remarkably, however, we find that the superpartner mass parameters in these models are still subject to many significant contraints. copyright 1997 The American Physical Society

Tools to probe the universe

International Nuclear Information System (INIS)

Lagage, P.O.; Augueres, J.L.; Amiaux, J.; Cara, Ch.; Fontignie, J.; Rio, Y.; Fermon, C.; Pannetier-Lecoeur, M.; De Vismes, A.; Cordier, B.; Fesquet, M.; Ferrando, Ph.; Authier, M.; Pantin, E.; Glicenstein, J.F.; Boulade, O.; Refregier, A.; Stolarczyk, Th.; Agnese, P.; Rodriguez, L.; Agnese, P.; Pigot, C.; Duband, L.; Limousin, O.; Delagnes, E.; Turck-Chieze, S.; Carton, P.H.; Starck, J.L.; Bournaud, F.; Teyssier, R.; Audit, E.; Brun, A.S.; Leca, P.; Menache, Ch.; Pomarede, D.; Thooris, B.; Meis, C.

2009-01-01

This special issue of Clefs CEA journal is entirely devoted to astrophysics and to the exploration and probing of the Universe. The second part of this dossier, described here, makes a status of the tools used to probe the universe: telescopes, imaging spectrometers, data processing and simulation. Content: A - Telescopes of the future: 1. Seeing further out: JWST: looking back on a past 13 billion years old, Space specifics: the learning curve to know-how, Fabricating a corona-graph mask, SVOM, a satellite to detect the explosions of the first stars to be formed in the Universe; 2. Seeing more precisely: SIMBOL-X, pioneering formation flying, ELT/METIS, a 42-meter giant, One hundred telescopes for the CTA arrays; 3. Seeing wider: Euclid, mapping the extragalactic sky, ANTARES: the neutrino, another cosmic messenger; B - The new generation of imaging spectrometers: Observing the Universe in the submillimeter spectral region, The X-ray Universe, Space cryo-coolers, Out in the extreme, tumultuous Universe, Probing the Sun with GOLF-NG, Focus: From light to imagery; C - Data analysis in astrophysics; D - Numerical simulation in astrophysics: Information technology and theoretical predictions in astrophysics, Supercomputers for a better understanding of the Universe, The visualization of astrophysical simulations, Godunov, a numerical platform for education and research

The Gravity Field of Mercury After the Messenger Low-Altitude Campaign

Science.gov (United States)

Mazarico, Erwan; Genova, Antonio; Goossens, Sander; Lemoine, Frank G.; Smith, David E.; Zuber, Maria T.; Neumann, Gary A.; Solomon, Sean C.

2015-01-01

The final year of the MESSENGER mission was designed to take advantage of the remaining propellant onboard to provide a series of lowaltitude observation campaigns and acquire novel scientific data about the innermost planet. The lower periapsis altitude greatly enhances the sensitivity to the short-wavelength gravity field, but only when the spacecraft is in view of Earth. After more than 3 years in orbit around Mercury, the MESSENGER spacecraft was tracked for the first time below 200-km altitude on 5 May 2014 by the NASA Deep Space Network (DSN). Between August and October, periapsis passages down to 25-km altitude were routinely tracked. These periods considerably improved the quality of the data coverage. Before the end of its mission, MESSENGER will fly at very low altitudes for extended periods of time. Given the orbital geometry, however the periapses will not be visible from Earth and so no new tracking data will be available for altitudes lower than 75 km. Nevertheless, the continuous tracking of MESSENGER in the northern hemisphere will help improve the uniformity of the spatial coverage at altitudes lower than 150 km, which will further improve the overall quality of the Mercury gravity field.

Alterations in polyribosome and messenger ribonucleic acid metabolism and messenger ribonucleoprotein utilization in osmotically stressed plant seedlings

International Nuclear Information System (INIS)

Mason, H.S.

1986-01-01

Polyribosome aggregation state in growing tissues of barley and wheat leaf of stems of pea and squash was studied in relation to seedling growth and water status of the growing tissue in plants at various levels of osmotic stress. It was found to be highly correlated with water potential and osmotic potential of the growing tissue and with leaf of stem elongation rate. Stress rapidly reduced polyribosome content and water status in growing tissues of barley leaves; changes were slow and slight in the non-growing leaf blade. Membrane-bound and free polyribosomes were equally sensitive to stress-induced disaggregation. Incorporation of 32 PO 4 3- into ribosomal RNA was rapidly inhibited by stress, but stability of poly(A) + RNA relative to ribosomal RNA was similar in stressed and unstressed tissues, with a half-life of about 12 hours. Stress also caused progressive loss of poly(A) + RNA from these tissues. Quantitation of poly(A) and in vitro messenger template activity in polysome gradient fractions showed a shift of activity from the polysomal region to the region of 20-60 S in stressed plants. Messenger RNA in the 20-60 S region coded for the same peptides as mRNA found in the polysomal fraction. Nonpolysomal and polysome-derived messenger ribonucleoprotein complexes (mRNP) were isolated, and characteristic proteins were found associated with either fraction. Polysomal mRNP from stressed or unstressed plants were translated with similar efficiency in a wheat germ cell-free system. It was concluded that no translational inhibitory activity was associated with nonpolysomal mRNP from barley prepared as described

Multi-point Shock and Flux Rope Analysis of Multiple Interplanetary Coronal Mass Ejections around 2010 August 1 in the Inner Heliosphere

Science.gov (United States)

Möstl, C.; Farrugia, C. J.; Kilpua, E. K. J.; Jian, L. K.; Liu, Y.; Eastwood, J. P.; Harrison, R. A.; Webb, D. F.; Temmer, M.; Odstrcil, D.; Davies, J. A.; Rollett, T.; Luhmann, J. G.; Nitta, N.; Mulligan, T.; Jensen, E. A.; Forsyth, R.; Lavraud, B.; de Koning, C. A.; Veronig, A. M.; Galvin, A. B.; Zhang, T. L.; Anderson, B. J.

2012-10-01

We present multi-point in situ observations of a complex sequence of coronal mass ejections (CMEs) which may serve as a benchmark event for numerical and empirical space weather prediction models. On 2010 August 1, instruments on various space missions, Solar Dynamics Observatory/Solar and Heliospheric Observatory/Solar-TErrestrial-RElations-Observatory (SDO/SOHO/STEREO), monitored several CMEs originating within tens of degrees from the solar disk center. We compare their imprints on four widely separated locations, spanning 120° in heliospheric longitude, with radial distances from the Sun ranging from MESSENGER (0.38 AU) to Venus Express (VEX, at 0.72 AU) to Wind, ACE, and ARTEMIS near Earth and STEREO-B close to 1 AU. Calculating shock and flux rope parameters at each location points to a non-spherical shape of the shock, and shows the global configuration of the interplanetary coronal mass ejections (ICMEs), which have interacted, but do not seem to have merged. VEX and STEREO-B observed similar magnetic flux ropes (MFRs), in contrast to structures at Wind. The geomagnetic storm was intense, reaching two minima in the Dst index (≈ - 100 nT), and was caused by the sheath region behind the shock and one of two observed MFRs. MESSENGER received a glancing blow of the ICMEs, and the events missed STEREO-A entirely. The observations demonstrate how sympathetic solar eruptions may immerse at least 1/3 of the heliosphere in the ecliptic with their distinct plasma and magnetic field signatures. We also emphasize the difficulties in linking the local views derived from single-spacecraft observations to a consistent global picture, pointing to possible alterations from the classical picture of ICMEs.

MULTI-POINT SHOCK AND FLUX ROPE ANALYSIS OF MULTIPLE INTERPLANETARY CORONAL MASS EJECTIONS AROUND 2010 AUGUST 1 IN THE INNER HELIOSPHERE

Energy Technology Data Exchange (ETDEWEB)

Moestl, C.; Liu, Y.; Luhmann, J. G. [Space Science Laboratory, University of California, Berkeley, CA (United States); Farrugia, C. J. [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH (United States); Kilpua, E. K. J. [Department of Physics, University of Helsinki, FI-00560 Helsinki (Finland); Jian, L. K. [Department of Astronomy, University of Maryland, College Park, MD (United States); Eastwood, J. P.; Forsyth, R. [The Blackett Laboratory, Imperial College, London (United Kingdom); Harrison, R. A.; Davies, J. A. [RAL Space, Harwell Oxford, Didcot (United Kingdom); Webb, D. F. [Institute for Scientific Research, Boston College, Newton, MA (United States); Temmer, M.; Rollett, T.; Veronig, A. M. [Kanzelhoehe Observatory-IGAM, Institute of Physics, University of Graz, A-8010 Graz (Austria); Odstrcil, D. [NASA Goddard Space Flight Center, Greenbelt, MD (United States); Nitta, N. [Solar and Astrophysics Laboratory, Lockheed Martin Advanced Technology Center, Palo Alto, CA (United States); Mulligan, T. [Space Science Applications Laboratory, The Aerospace Corporation, El Segundo, CA (United States); Jensen, E. A. [ACS Consulting, Houston, TX (United States); Lavraud, B. [Institut de Recherche en Astrophysique et Planetologie, Universite de Toulouse (UPS), F-31400 Toulouse (France); De Koning, C. A., E-mail: christian.moestl@uni-graz.at [NOAA/SWPC, Boulder, Colorado (United States); and others

2012-10-10

We present multi-point in situ observations of a complex sequence of coronal mass ejections (CMEs) which may serve as a benchmark event for numerical and empirical space weather prediction models. On 2010 August 1, instruments on various space missions, Solar Dynamics Observatory/Solar and Heliospheric Observatory/Solar-TErrestrial-RElations-Observatory (SDO/SOHO/STEREO), monitored several CMEs originating within tens of degrees from the solar disk center. We compare their imprints on four widely separated locations, spanning 120 Degree-Sign in heliospheric longitude, with radial distances from the Sun ranging from MESSENGER (0.38 AU) to Venus Express (VEX, at 0.72 AU) to Wind, ACE, and ARTEMIS near Earth and STEREO-B close to 1 AU. Calculating shock and flux rope parameters at each location points to a non-spherical shape of the shock, and shows the global configuration of the interplanetary coronal mass ejections (ICMEs), which have interacted, but do not seem to have merged. VEX and STEREO-B observed similar magnetic flux ropes (MFRs), in contrast to structures at Wind. The geomagnetic storm was intense, reaching two minima in the Dst index ( Almost-Equal-To - 100 nT), and was caused by the sheath region behind the shock and one of two observed MFRs. MESSENGER received a glancing blow of the ICMEs, and the events missed STEREO-A entirely. The observations demonstrate how sympathetic solar eruptions may immerse at least 1/3 of the heliosphere in the ecliptic with their distinct plasma and magnetic field signatures. We also emphasize the difficulties in linking the local views derived from single-spacecraft observations to a consistent global picture, pointing to possible alterations from the classical picture of ICMEs.

ESTRADIOL-INDUCED SYNTHESIS OF VITELLOGENIN .3. ISOLATION AND CHARACTERIZATION OF VITELLOGENIN MESSENGER-RNA FROM AVIAN LIVER

NARCIS (Netherlands)

AB, G.; Roskam, W. G.; Dijkstra, J.; Mulder, J.; Willems, M.; van der Ende, A.; Gruber, M.

1976-01-01

The messenger RNA of the hormone-induced protein vitellogenin was isolated from the liver of estrogen-treated roosters. Starting from total polysomal RNA, the vitellogenin messenger was purified 67-fold by oligo (dT)-cellulose chromatography and sizing on a sucrose gradient. The messenger was

12 CFR 7.1012 - Messenger service.

Science.gov (United States)

2010-01-01

... service” means any service, such as a courier service or armored car service, used by a national bank and... service do not advertise, or otherwise represent, that the bank itself is providing the service, although the bank may advertise that its customers may use one or more third party messenger services to...

MESSENGER: Exploring Mercury's Magnetosphere

Science.gov (United States)

Slavin, James A.

2008-01-01

The MESSENGER mission to Mercury offers our first opportunity to explore this planet's miniature magnetosphere since Mariner 10's brief fly-bys in 1974-5. Mercury's magnetosphere is unique in many respects. The magnetosphere of Mercury is the smallest in the solar system with its magnetic field typically standing off the solar wind only - 1000 to 2000 km above the surface. For this reason there are no closed dri-fi paths for energetic particles and, hence, no radiation belts; the characteristic time scales for wave propagation and convective transport are short possibly coupling kinetic and fluid modes; magnetic reconnection at the dayside magnetopause may erode the subsolar magnetosphere allowing solar wind ions to directly impact the dayside regolith; inductive currents in Mercury's interior should act to modify the solar In addition, Mercury's magnetosphere is the only one with its defining magnetic flux tubes rooted in a planetary regolith as opposed to an atmosphere with a conductive ionosphere. This lack of an ionosphere is thought to be the underlying reason for the brevity of the very intense, but short lived, approx. 1-2 min, substorm-like energetic particle events observed by Mariner 10 in Mercury's magnetic tail. In this seminar, we review what we think we know about Mercury's magnetosphere and describe the MESSENGER science team's strategy for obtaining answers to the outstanding science questions surrounding the interaction of the solar wind with Mercury and its small, but dynamic magnetosphere.

Tracking heliospheric disturbances by interplanetary scintillation

Directory of Open Access Journals (Sweden)

M. Tokumaru

2006-01-01

Full Text Available Coronal mass ejections are known as a solar cause of significant geospace disturbances, and a fuller elucidation of their physical properties and propagation dynamics is needed for space weather predictions. The scintillation of cosmic radio sources caused by turbulence in the solar wind (interplanetary scintillation; IPS serves as an effective ground-based method for monitoring disturbances in the heliosphere. We studied global properties of transient solar wind streams driven by CMEs using 327-MHz IPS observations of the Solar-Terrestrial Environment Laboratory (STEL of Nagoya University. In this study, we reconstructed three-dimensional features of the interplanetary (IP counterpart of the CME from the IPS data by applying the model fitting technique. As a result, loop-shaped density enhancements were deduced for some CME events, whereas shell-shaped high-density regions were observed for the other events. In addition, CME speeds were found to evolve significantly during the propagation between the corona and 1 AU.

Multi-Messenger Astronomy with Gravitational Waves

Indian Academy of Sciences (India)

Sound + images show Bailey was out in the India-Australia match on 12 Jan 2016. Image credit: Rediff / Fox news / Twitter. Page 10. Electromagnetic follow up: the Indian context. Page 11. Multi-Messenger Astronomy with Gravitational Waves | LIGO-G1601377-v2. Varun Bhalerao (IUCAA) | 1 July 2016. 11. 20 – 60 keV:.

Multi-Messenger Astronomy and Dark Matter

Science.gov (United States)

Bergström, Lars

This chapter presents the elaborated lecture notes on Multi-Messenger Astronomy and Dark Matter given by Lars Bergström at the 40th Saas-Fee Advanced Course on "Astrophysics at Very High Energies". One of the main problems of astrophysics and astro-particle physics is that the nature of dark matter remains unsolved. There are basically three complementary approaches to try to solve this problem. One is the detection of new particles with accelerators, the second is the observation of various types of messengers from radio waves to gamma-ray photons and neutrinos, and the third is the use of ingenious experiments for direct detection of dark matter particles. After giving an introduction to the particle universe, the author discusses the relic density of particles, basic cross sections for neutrinos and gamma-rays, supersymmetric dark matter, detection methods for neutralino dark matter, particular dark matter candidates, the status of dark matter detection, a detailled calculation on an hypothetical "Saas-Fee Wimp", primordial black holes, and gravitational waves.

Relationship between Interplanetary (IP) Parameters and ...

Indian Academy of Sciences (India)

3SITAA-SAC, Indian Space Research Organisation, Ahmedabad, Gujarat 380 015, India. 4Indian Space Research Organisation-Head Quarters, Bangalore, Karnataka, India. Abstract. In the present study, .... Lepping, R. P., Jones, J. A., Burlaga, L. F. 1990, Magnetic field structure of Interplanetary. Magnetic Clouds at 1 A.U; ...

MESSENGER and Mariner 10 Flyby Observations of Magnetotail Structure and Dynamics at Mercury

Science.gov (United States)

Slavin, James A.; Anderson, Brian Jay; Baker, Daniel N.; Benna, Mehdi; Boardsen, Scott A.; Gold, Robert E.; Ho, George C.; Imber, Suzanne M.; Korth, Haje; Krimigis, Stamatios, M.;

Phenotypic characterization of neurotensin messenger RNA-expressing cells in the neuroleptic-treated rat striatum: a detailed cellular co-expression study

Energy Technology Data Exchange (ETDEWEB)

Emson, P C; Westmore, K; Augood, S J [MRC Molecular Neuroscience Group, The Department of Neurobiology, The Babraham Institute, Babraham, Cambridge (United Kingdom)

1996-12-11

The chemical phenotype of proneurotensin messenger RNA-expressing cells was determined in the acute haloperidol-treated rat striatum using a combination of [{sup 35}S]-labelled and alkaline phosphatase-labelled oligonucleotides. Cellular sites of proneurotensin messenger RNA expression were visualized simultaneously on tissue sections processed to reveal cellular sites of preproenkephalin A messenger RNA or the dopamine and adenylate cyclase phosphoprotein-32, messenger RNA. The cellular co-expression of preproenkepahlin A and preprotachykinin messenger RNA was also examined within forebrain structures. Cellular sites of preproenkephalin A and dopamine and adenylate cyclase phosphoprotein-32 messenger RNAs were visualized using alkaline phosphatase-labelled oligonucleotides whilst sites of preprotachykinin and proneurotensin messenger RNA expression were detected using [{sup 35}S]-labelled oligos. Cellular sites of enkephalin and dopamine and adenylate cyclase phosphoprotein-32 gene expression were identified microscopically by the concentration of purple alkaline phosphatase reaction product within the cell cytoplasm, whereas sites of substance P and proneurotensin gene expression were identified by the dense clustering of silver grains overlying cells.An intense hybridization signal was detected for all three neuropeptide messenger RNAs in the striatum, the nucleus accumbens and septum. Dopamine and adenylate cyclase phosphoprotein-32 messenger RNA was detected within the neostriatum but not within the septum. In all forebrain regions examined, with the exception of the islands of Cajella, the cellular expression of enkephalin messenger RNA and substance P messenger RNA was discordant; the two neuropeptide messenger RNAs were detected essentially in different cells, although in the striatum and nucleus accumbens occasional isolated cells were detected which contained both hybridization signals; dense clusters of silver grains overlay alkaline phosphatase

Phenotypic characterization of neurotensin messenger RNA-expressing cells in the neuroleptic-treated rat striatum: a detailed cellular co-expression study

International Nuclear Information System (INIS)

Emson, P.C.; Westmore, K.; Augood, S.J.

1996-01-01

The chemical phenotype of proneurotensin messenger RNA-expressing cells was determined in the acute haloperidol-treated rat striatum using a combination of [ 35 S]-labelled and alkaline phosphatase-labelled oligonucleotides. Cellular sites of proneurotensin messenger RNA expression were visualized simultaneously on tissue sections processed to reveal cellular sites of preproenkephalin A messenger RNA or the dopamine and adenylate cyclase phosphoprotein-32, messenger RNA. The cellular co-expression of preproenkepahlin A and preprotachykinin messenger RNA was also examined within forebrain structures. Cellular sites of preproenkephalin A and dopamine and adenylate cyclase phosphoprotein-32 messenger RNAs were visualized using alkaline phosphatase-labelled oligonucleotides whilst sites of preprotachykinin and proneurotensin messenger RNA expression were detected using [ 35 S]-labelled oligos. Cellular sites of enkephalin and dopamine and adenylate cyclase phosphoprotein-32 gene expression were identified microscopically by the concentration of purple alkaline phosphatase reaction product within the cell cytoplasm, whereas sites of substance P and proneurotensin gene expression were identified by the dense clustering of silver grains overlying cells.An intense hybridization signal was detected for all three neuropeptide messenger RNAs in the striatum, the nucleus accumbens and septum. Dopamine and adenylate cyclase phosphoprotein-32 messenger RNA was detected within the neostriatum but not within the septum. In all forebrain regions examined, with the exception of the islands of Cajella, the cellular expression of enkephalin messenger RNA and substance P messenger RNA was discordant; the two neuropeptide messenger RNAs were detected essentially in different cells, although in the striatum and nucleus accumbens occasional isolated cells were detected which contained both hybridization signals; dense clusters of silver grains overlay alkaline phosphatase-positive cells

Nonthermal Radiation Processes in Interplanetary Plasmas

Science.gov (United States)

Chian, A. C. L.

1990-11-01

RESUMEN. En la interacci6n de haces de electrones energeticos con plasmas interplanetarios, se excitan ondas intensas de Langmuir debido a inestabilidad del haz de plasma. Las ondas Langmuir a su vez interaccio nan con fluctuaciones de densidad de baja frecuencia para producir radiaciones. Si la longitud de las ondas de Langmujr exceden las condicio nes del umbral, se puede efectuar la conversi5n de modo no lineal a on- das electromagneticas a traves de inestabilidades parametricas. As se puede excitar en un plasma inestabilidades parametricas electromagneticas impulsadas por ondas intensas de Langmuir: (1) inestabilidades de decaimiento/fusi5n electromagnetica impulsadas por una bomba de Lang- muir que viaja; (2) inestabilidades dobles electromagneticas de decai- miento/fusi5n impulsadas por dos bombas de Langrnuir directamente opues- tas; y (3) inestabilidades de dos corrientes oscilatorias electromagne- ticas impulsadas por dos bombas de Langmuir de corrientes contrarias. Se concluye que las inestabilidades parametricas electromagneticas in- ducidas por las ondas de Langmuir son las fuentes posibles de radiacio- nes no termicas en plasmas interplanetarios. ABSTRACT: Nonthermal radio emissions near the local electron plasma frequency have been detected in various regions of interplanetary plasmas: solar wind, upstream of planetary bow shock, and heliopause. Energetic electron beams accelerated by solar flares, planetary bow shocks, and the terminal shock of heliosphere provide the energy source for these radio emissions. Thus, it is expected that similar nonthermal radiation processes may be responsible for the generation of these radio emissions. As energetic electron beams interact with interplanetary plasmas, intense Langmuir waves are excited due to a beam-plasma instability. The Langmuir waves then interact with low-frequency density fluctuations to produce radiations near the local electron plasma frequency. If Langmuir waves are of sufficiently large

Search Coil vs. Fluxgate Magnetometer Measurements at Interplanetary Shocks

Science.gov (United States)

Wilson, L.B., III

2012-01-01

We present magnetic field observations at interplanetary shocks comparing two different sample rates showing significantly different results. Fluxgate magnetometer measurements show relatively laminar supercritical shock transitions at roughly 11 samples/s. Search coil magnetometer measurements at 1875 samples/s, however, show large amplitude (dB/B as large as 2) fluctuations that are not resolved by the fluxgate magnetometer. We show that these fluctuations, identified as whistler mode waves, would produce a significant perturbation to the shock transition region changing the interpretation from laminar to turbulent. Thus, previous observations of supercritical interplanetary shocks classified as laminar may have been under sampled.

Phenomenologies of Higgs messenger models

Energy Technology Data Exchange (ETDEWEB)

Zheng Sibo; Yu Yao; Wu Xinggang [Department of Physics, Chongqing University, Chongqing 401331 (China)

2011-08-11

In this Letter, we investigate the phenomenologies of models where the Higgs sector plays the role of messengers in gauge mediation. The minimal Higgs sector and its extension are considered respectively. We find that there exist viable models when an appropriate parity is imposed. Phenomenological features in these kind of models include three sum rules for scalar masses, light gluino as well as one-loop {mu} and two-loop B{mu} terms.

Propagation Characteristics of Two Coronal Mass Ejections from the Sun Far into Interplanetary Space

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xiaowei; Liu, Ying D.; Hu, Huidong; Wang, Rui, E-mail: liuxying@spaceweather.ac.cn [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China)

2017-03-01

Propagation of coronal mass ejections (CMEs) from the Sun far into interplanetary space is not well understood, due to limited observations. In this study we examine the propagation characteristics of two geo-effective CMEs, which occurred on 2005 May 6 and 13, respectively. Significant heliospheric consequences associated with the two CMEs are observed, including interplanetary CMEs (ICMEs) at the Earth and Ulysses , interplanetary shocks, a long-duration type II radio burst, and intense geomagnetic storms. We use coronagraph observations from SOHO /LASCO, frequency drift of the long-duration type II burst, in situ measurements at the Earth and Ulysses , and magnetohydrodynamic propagation of the observed solar wind disturbances at 1 au to track the CMEs from the Sun far into interplanetary space. We find that both of the CMEs underwent a major deceleration within 1 au and thereafter a gradual deceleration when they propagated from the Earth to deep interplanetary space, due to interactions with the ambient solar wind. The results also reveal that the two CMEs interacted with each other in the distant interplanetary space even though their launch times on the Sun were well separated. The intense geomagnetic storm for each case was caused by the southward magnetic fields ahead of the CME, stressing the critical role of the sheath region in geomagnetic storm generation, although for the first case there is a corotating interaction region involved.

Astronomy's New Messengers: A traveling exhibit on gravitational-wave physics

International Nuclear Information System (INIS)

Cavaglia, Marco; Hendry, Martin; Marka, Szabolcs; Reitze, David H; Riles, Keith

2010-01-01

The Laser Interferometer Gravitational-wave Observatory exhibit Astronomy's New Messengers: Listening to the Universe with Gravitational Waves is traveling to colleges, universities, museums and other public institutions throughout the United States. Astronomy's New Messengers primarily communicates with an adolescent and young adult audience, potentially inspiring them into the field of science. Acknowledging that this audience is traditionally a difficult one to attract, the exhibit publicly announces itself in a charismatic fashion to reach its principal goals of broadening the community of people interested in science and encouraging interest in science among young people.

Light third-generation squarks from flavour gauge messengers

International Nuclear Information System (INIS)

Brümmer, Felix; McGarrie, Moritz; Weiler, Andreas

2014-01-01

We study models of gauge-mediated supersymmetry breaking with a gauged horizontal SU(3) F symmetry acting on the quark superfields. If SU(3) F is broken non-supersymmetrically by F-term vacuum expectation values, the massive gauge bosons and gauginos become messengers for SUSY breaking mediation. These gauge messenger fields induce a flavour-dependent, negative contribution to the soft masses of the squarks at one loop. In combination with the soft terms from standard gauge mediation, one obtains large and degenerate first- and second-generation squark masses, while the stops and sbottoms are light. We discuss the implications of this mechanism for the superparticle spectrum and for flavour precision observables. We also provide an explicit realization in a model with simultaneous SUSY and SU(3) F breaking

Light third-generation squarks from flavour gauge messengers

International Nuclear Information System (INIS)

Bruemmer, Felix; McGarrie, Moritz; Univ. of the Witwatersrand, Johannesburg; Weiler, Andreas; CERN - European Organization for Nuclear Research, Geneva

2014-04-01

We study models of gauge-mediated supersymmetry breaking with a gauged horizontal SU(3) F symmetry acting on the quark superfields. If SU(3) F is broken non-supersymmetrically by F-term vacuum expectation values, the massive gauge bosons and gauginos become messengers for SUSY breaking mediation. These gauge messenger fields induce a flavour-dependent, negative contribution to the soft masses of the squarks at one loop. In combination with the soft terms from standard gauge mediation, one obtains large and degenerate first- and second-generation squark masses, while the stops and sbottoms are light. We discuss the implications of this mechanism for the superparticle spectrum and for flavour precision observables. We also provide an explicit realization in a model with simultaneous SUSY and SU(3) F breaking.

Study of Travelling Interplanetary Phenomena (STIP) workshop travel

Science.gov (United States)

Wu, S. T.

1986-01-01

Thirty six abstracts are provided from the SCOSTEP/STIP Symposium on Retrospective Analyses and Future Coordinated Intervals held in Switzerland on June 10 to 12, 1985. Six American scientists participated in the symposium and their abstracts are also included. The titles of their papers are: (1) An analysis of near surface and coronal activity during STIP interval 12, by T. E. Gergely; (2) Helios images of STIP intervals 6, B. V. Jackson; (3) Results from the analysis of solar and interplanetary observations during STIP interval 7, S. R. Kane; (4) STIP interval 19, E. Cliver; (5) Hydrodynamic buoyancy force in the solar atmosphere, T. Yeh; and (6) A combined MHD modes for the energy and momentum transport from solar surface to interplanetary space, S. T. Wu.

Preconditioning of Interplanetary Space Due to Transient CME Disturbances

International Nuclear Information System (INIS)

Temmer, M.; Reiss, M. A.; Hofmeister, S. J.; Veronig, A. M.; Nikolic, L.

2017-01-01

Interplanetary space is characteristically structured mainly by high-speed solar wind streams emanating from coronal holes and transient disturbances such as coronal mass ejections (CMEs). While high-speed solar wind streams pose a continuous outflow, CMEs abruptly disrupt the rather steady structure, causing large deviations from the quiet solar wind conditions. For the first time, we give a quantification of the duration of disturbed conditions (preconditioning) for interplanetary space caused by CMEs. To this aim, we investigate the plasma speed component of the solar wind and the impact of in situ detected interplanetary CMEs (ICMEs), compared to different background solar wind models (ESWF, WSA, persistence model) for the time range 2011–2015. We quantify in terms of standard error measures the deviations between modeled background solar wind speed and observed solar wind speed. Using the mean absolute error, we obtain an average deviation for quiet solar activity within a range of 75.1–83.1 km s −1 . Compared to this baseline level, periods within the ICME interval showed an increase of 18%–32% above the expected background, and the period of two days after the ICME displayed an increase of 9%–24%. We obtain a total duration of enhanced deviations over about three and up to six days after the ICME start, which is much longer than the average duration of an ICME disturbance itself (∼1.3 days), concluding that interplanetary space needs ∼2–5 days to recover from the impact of ICMEs. The obtained results have strong implications for studying CME propagation behavior and also for space weather forecasting.

Preconditioning of Interplanetary Space Due to Transient CME Disturbances

Energy Technology Data Exchange (ETDEWEB)

Temmer, M.; Reiss, M. A.; Hofmeister, S. J.; Veronig, A. M. [Institute of Physics, University of Graz, Universitätsplatz 5/II, A-8010 Graz (Austria); Nikolic, L., E-mail: manuela.temmer@uni-graz.at [Canadian Hazards Information Service, Natural Resources Canada, 2617 Anderson Road, Ottawa, Ontario K1A 0Y3 (Canada)

2017-02-01

Interplanetary space is characteristically structured mainly by high-speed solar wind streams emanating from coronal holes and transient disturbances such as coronal mass ejections (CMEs). While high-speed solar wind streams pose a continuous outflow, CMEs abruptly disrupt the rather steady structure, causing large deviations from the quiet solar wind conditions. For the first time, we give a quantification of the duration of disturbed conditions (preconditioning) for interplanetary space caused by CMEs. To this aim, we investigate the plasma speed component of the solar wind and the impact of in situ detected interplanetary CMEs (ICMEs), compared to different background solar wind models (ESWF, WSA, persistence model) for the time range 2011–2015. We quantify in terms of standard error measures the deviations between modeled background solar wind speed and observed solar wind speed. Using the mean absolute error, we obtain an average deviation for quiet solar activity within a range of 75.1–83.1 km s{sup −1}. Compared to this baseline level, periods within the ICME interval showed an increase of 18%–32% above the expected background, and the period of two days after the ICME displayed an increase of 9%–24%. We obtain a total duration of enhanced deviations over about three and up to six days after the ICME start, which is much longer than the average duration of an ICME disturbance itself (∼1.3 days), concluding that interplanetary space needs ∼2–5 days to recover from the impact of ICMEs. The obtained results have strong implications for studying CME propagation behavior and also for space weather forecasting.

Latitudinal Dependence of the Radial IMF Component - Interplanetary Imprint

Science.gov (United States)

Suess, S. T.; Smith, E. J.; Phillips, J.; Goldstein, B. E.; Nerney, S.

1996-01-01

Ulysses measurements have confirmed that there is no significant gradient with respect to heliomagnetic latitude in the radial component, B(sub r,), of the interplanetary magnetic field. There are two processes responsible for this observation. In the corona, the plasma beta is much less than 1, except directly above streamers, so both longitudinal and latitudinal (meridional) gradients in field strength will relax, due to the transverse magnetic pressure gradient force, as the solar wind carries magnetic flux away from the Sun. This happens so quickly that the field is essentially uniform by 5 solar radius. Beyond 10 solar radius, beta is greater than 1 and it is possible for a meridional thermal pressure gradient to redistribute magnetic flux - an effect apparently absent in Ulysses and earlier ICE and Interplanetary Magnetic Physics (IMP) data. We discuss this second effect here, showing that its absence is mainly due to the perpendicular part of the anisotropic thermal pressure gradient in the interplanetary medium being too small to drive significant meridional transport between the Sun and approx. 4 AU. This is done using a linear analytic estimate of meridional transport. The first effect was discussed in an earlier paper.

Altered expression of estrogen receptor-α variant messenger RNAs between adjacent normal breast and breast tumor tissues

International Nuclear Information System (INIS)

Leygue, Etienne; Dotzlaw, Helmut; Watson, Peter H; Murphy, Leigh C

2000-01-01

Using semiquantitative reverse transcription-polymerase chain reaction assays, we investigated the expression of variant messenger RNAs relative to wild-type estrogen receptor (ER)-α messenger RNA in normal breast tissues and their adjacent matched breast tumor tissues. Higher ER variant truncated after sequences encoding exon 2 of the wild-type ER-α (ERC4) messenger RNA and a lower exon 3 deleted ER-α variant (ERD3) messenger RNA relative expression in the tumor compartment were observed in the ER-positive/PR-positive and the ER-positive subsets, respectively. A significantly higher relative expression of exon 5 deleted ER-α varient (ERD5) messenger RNA was observed in tumor components overall. These data demonstrate that changes in the relative expression of ER-α variant messenger RNAs occur between adjacent normal and neoplastic breast tissues. We suggest that these changes might be involved in the mechanisms that underlie breast tumorigenesis. Estrogen receptor (ER)-α and ER-β are believed to mediate the action of estradiol in target tissues. Several ER-α and ER-β variant messenger RNAs have been identified in both normal and neoplastic human tissues. Most of these variants contain a deletion of one or more exons of the wild-type (WT) ER messenger RNAs. The putative proteins that are encoded by these variant messenger RNAs would therefore be missing some functional domains of the WT receptors, and might interfere with WT-ER signaling pathways. The detection of ER-α variants in both normal and neoplastic human breast tissues raised the question of their possible role in breast tumorigenesis. We have previously reported an increased relative expression of exon 5 deleted ER-α variant (ERD5) messenger RNA and of another ER-α variant truncated of all sequences following the exon 2 of the WT ER-α (ERC4) messenger RNA in breast tumor samples versus independent normal breast tissues. In contrast, a decreased relative expression of exon 3 deleted ER

The Radiation, Interplanetary Shocks, and Coronal Sources (RISCS) Toolset

Science.gov (United States)

Zank, G. P.; Spann, James F.

2014-01-01

The goal of this project is to serve the needs of space system designers and operators by developing an interplanetary radiation environment model within 10 AU:Radiation, Interplanetary Shocks, and Coronal Sources (RISCS) toolset: (1) The RISCS toolset will provide specific reference environments for space system designers and nowcasting and forecasting capabilities for space system operators; (2) We envision the RISCS toolset providing the spatial and temporal radiation environment external to the Earth's (and other planets') magnetosphere, as well as possessing the modularity to integrate separate applications (apps) that can map to specific magnetosphere locations and/or perform the subsequent radiation transport and dosimetry for a specific target.

Planetary Ions at Mercury: Unanswered Questions After MESSENGER

Science.gov (United States)

Raines, J. M.

2018-05-01

We will discuss the key open questions relating to planetary ions, including the behavior of recently created photoions, the near absence of Ca+ / K+ in MESSENGER ion measurements, and the role of ion sputtering in the system.

Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Takuya; Shibata, Kazunari, E-mail: takahasi@kusastro.kyoto-u.ac.jp [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607–8471 (Japan)

2017-03-10

Fast interplanetary coronal mass ejections (ICMEs) are the drivers of strong space weather storms such as solar energetic particle events and geomagnetic storms. The connection between the space-weather-impacting solar wind disturbances associated with fast ICMEs at Earth and the characteristics of causative energetic CMEs observed near the Sun is a key question in the study of space weather storms, as well as in the development of practical space weather prediction. Such shock-driving fast ICMEs usually expand at supersonic speeds during the propagation, resulting in the continuous accumulation of shocked sheath plasma ahead. In this paper, we propose a “sheath-accumulating propagation” (SAP) model that describes the coevolution of the interplanetary sheath and decelerating ICME ejecta by taking into account the process of upstream solar wind plasma accumulation within the sheath region. Based on the SAP model, we discuss (1) ICME deceleration characteristics; (2) the fundamental condition for fast ICMEs at Earth; (3) the thickness of interplanetary sheaths; (4) arrival time prediction; and (5) the super-intense geomagnetic storms associated with huge solar flares. We quantitatively show that not only the speed but also the mass of the CME are crucial for discussing the above five points. The similarities and differences between the SAP model, the drag-based model, and the“snow-plow” model proposed by Tappin are also discussed.

Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

International Nuclear Information System (INIS)

Takahashi, Takuya; Shibata, Kazunari

2017-01-01

Fast interplanetary coronal mass ejections (ICMEs) are the drivers of strong space weather storms such as solar energetic particle events and geomagnetic storms. The connection between the space-weather-impacting solar wind disturbances associated with fast ICMEs at Earth and the characteristics of causative energetic CMEs observed near the Sun is a key question in the study of space weather storms, as well as in the development of practical space weather prediction. Such shock-driving fast ICMEs usually expand at supersonic speeds during the propagation, resulting in the continuous accumulation of shocked sheath plasma ahead. In this paper, we propose a “sheath-accumulating propagation” (SAP) model that describes the coevolution of the interplanetary sheath and decelerating ICME ejecta by taking into account the process of upstream solar wind plasma accumulation within the sheath region. Based on the SAP model, we discuss (1) ICME deceleration characteristics; (2) the fundamental condition for fast ICMEs at Earth; (3) the thickness of interplanetary sheaths; (4) arrival time prediction; and (5) the super-intense geomagnetic storms associated with huge solar flares. We quantitatively show that not only the speed but also the mass of the CME are crucial for discussing the above five points. The similarities and differences between the SAP model, the drag-based model, and the“snow-plow” model proposed by Tappin are also discussed.

Analysis Of Interplanetary Phenomenon, Geomagnetic And ...

African Journals Online (AJOL)

The storm was found to be a double step storm with the first Dstmin resulting mainly from ring current injection due to increase in solar wind density while magnetospheric convection electric field played the leading role in the development of the second Dstmin . The analysis of the interplanetary and foF2 data show that the ...

Effects of ionizing radiation and partial hepatectomy on messenger RNA synthesis

International Nuclear Information System (INIS)

Abdel-Halim, M.N.

1979-01-01

Newly synthesized messenger RNA, as measured by a 40 min uptake of the radioactive precursor (6- 14 C) orotic acid, was studied in the regenerating livers of non-irradiated and gamma-irradiated (1800 rad) adrenal-intact and adrenalectomized rats 24 and 48 hours after partial hepatectomy. Two groups of rats, one with and one without adrenal glands were each divided into four subgroups: (1) control rats, (2) irradiated rats, (3) partially hepatectomized rats and (4) irradiated, partially hepatectomized rats. The radioactive profile of polyribosome formation and distribution was determined by sucrose density gradient centrifugation (10 to 40 per cent). The result of this study indicates that ionizing radiation decreases the synthesis of newly formed messenger RNA in regenerating livers of adrenal-intact rats. However, adrenalectomy largely abolished that inhibition. These data suggest that the decrease in messenger RNA synthesis may be explained by the disturbance of adrenal hormones induced by partial hepatectomy and ionizing radiation. (author)

Manifestation of interplanetary medium parameters in development of a geomagnetic storm initial phase

International Nuclear Information System (INIS)

Chkhetiya, A.M.

1988-01-01

The role of solar wind plasma parameters in formation of a geomagnetic storm initial phase is refined. On the basis of statistical analysis an empirical formula relating the interplanetary medium parameters (components of interplanetary magnetic field, proton velocity and concentration) and D st -index during the geomagnetic storm initial phase is proposed

Pathophysiological implications of the chemical messengers

International Nuclear Information System (INIS)

Blazquez Fernandez, E.

2009-01-01

To maintain a physical organization and a different composition of its surroundings environment, living beings use a great part of the energy that they produce. Vital processes require an elevated number of reactions which are regulated and integrated by chemical messengers. They use autocrine, paracrine, endocrine and synaptic signals through receptors of cell surface, nuclear or associated with ionic channels, enzymes, trim eric G proteins and to intracellular kinases. Through these mechanisms pheromones play an important role in the relationships between different individuals, and hormones are able to regulate the integrative functions of our organism. In the nervous system, neurotransmitters, neuromodulators, sensors and receptors between other messengers, play functions of great relevance, while growth factors stimulate cell proliferation and cytokines have many effects but the most important is the ones related with the control of the immflamatory process. Alterations of these messengers permit us a better understanding of the diseases and possibly of its treatments in a near future. Modifications of the expression of genes from the nuclear and mitochondrial genomes are responsible of monogenic, polygenic and mitochondrial diseases, while alterations in the activities of dopamine and serotonin neurotransmitters are related with schizophrenia, Parkinson disease and depression, respectively. Other example is the hyperthyroidism of the Graves-Bassedow disease due to the competitive interference of the LATS immunoglobulin with TSH at the level of the follicular cells producing thyroid hormones Twenty five years ago in the reviews on the mechanisms of insulin action, there was presentations in which the insulin receptor was located in the plasma membrane of the target cells while in the cytoplasm only a big interrogative was observed, that at present is replaced by chemical mediators cascades responsible of the multiple effects of insulin. This finding is similar

Detailed mapping of serotonin 5-HT1B and 5-HT1D receptor messenger RNA and ligand binding sites in guinea-pig brain and trigeminal ganglion: clues for function

International Nuclear Information System (INIS)

Leysen, J.E.; Schotte, A.; Jurzak, M.; Luyten, W.H.M.L.; Voorn, P.; Bonaventure, P.

1997-01-01

The similar pharmacology of the 5-HT 1B and 5-HT 1D receptors, and the lack of selective compounds sufficiently distinguishing between the two receptor subtypes, have hampered functional studies on these receptors. In order to provide clues for differential functional roles of the two subtypes, we performed a parallel localization study throughout the guinea-pig brain and the trigeminal ganglia by means of quantitative in situ hybridization histochemistry (using [ 35 S]-labelled riboprobes probes for receptor messenger RNA) and receptor autoradiography (using a new radioligand [ 3 H]alniditan).The anatomical patterns of 5-HT 1B and 5-HT 1D receptor messenger RNA were quite different. While 5-HT 1B receptor messenger RNA was abundant throughout the brain (with highest levels in the striatum, nucleus accumbens, olfactory tubercle, cortex, hypothalamus, hippocampal formation, amygdala, thalamus, dorsal raphe and cerebellum), 5-HT 1D receptor messenger RNA exhibited a more restricted pattern; it was found mainly in the olfactory tubercle, entorhinal cortex, dorsal raphe, cerebellum, mesencephalic trigeminal nucleus and in the trigeminal ganglion. The density of 5-HT 1B/1D binding sites (combined) obtained with [ 3 H]alniditan autoradiography was high in the substantia nigra, superior colliculus and globus pallidus, whereas lower levels were detected in the caudate-putamen, hypothalamus, hippocampal formation, amygdala, thalamus and central gray. This distribution pattern was indistinguishable from specific 5-HT 1B receptor labelling in the presence of ketanserin under conditions to occlude 5-HT 1D receptor labelling; hence the latter were below detection level. Relationships between the regional distributions of the receptor messenger RNAs and binding sites and particular neuroanatomical pathways are discussed with respect to possible functional roles of the 5-HT 1B and 5-HT 1D receptors. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

WhatsApp Messenger as an Adjunctive Tool for Telemedicine: An Overview.

Science.gov (United States)

Giordano, Vincenzo; Koch, Hilton; Godoy-Santos, Alexandre; Dias Belangero, William; Esteves Santos Pires, Robinson; Labronici, Pedro

2017-07-21

The advent of telemedicine has allowed physicians to deliver medical treatment to patients from a distance. Mobile apps such as WhatsApp Messenger, an instant messaging service, came as a novel concept in all fields of social life, including medicine. The use of instant messaging services has been shown to improve communication within medical teams by providing means for quick teleconsultation, information sharing, and starting treatment as soon as possible. The aim of this study was to perform a comprehensive systematic review of present literature on the use of the WhatsApp Messenger app as an adjunctive health care tool for medical doctors. Searches were performed in PubMed, EMBASE, and the Cochrane Library using the term "whatsapp*" in articles published before January 2016. A bibliography of all relevant original articles that used the WhatsApp Messenger app was created. The level of evidence of each study was determined according to the Oxford Levels of Evidence ranking system produced by the Oxford Centre for Evidence-Based Medicine. The impact and the indications of WhatsApp Messenger are discussed in order to understand the extent to which this app currently functions as an adjunctive tool for telemedicine. The database search identified a total of 30 studies in which the term "whatsapp*" was used. Each article's list of references was evaluated item-by-item. After literature reviews, letters to the editor, and low-quality studies were excluded, a total of 10 studies were found to be eligible for inclusion. Of these studies, 9 had been published in the English language and 1 had been published in Spanish. Five were published by medical doctors. The pooled data presents compelling evidence that the WhatsApp Messenger app is a promising system, whether used as a communication tool between health care professionals, as a means of communication between health care professionals and the general public, or as a learning tool for providing health care information

Segundos mensajeros Second messengers

Directory of Open Access Journals (Sweden)

Diana Patricia Díaz Hernández

1989-01-01

Full Text Available

En esta revisión se describen, de manera esquemática, los mecanismos de acción empleados por los SEGUNDOS MENSAJEROS comenzando por el estimulo del receptor y continuando con las reacciones en cadena que conducen finalmente a una respuesta celular.

This review schematically describes the different mechanisms of action that Second Messengers employ to stimulate receptors and then Initiate a chain of reactions that finally lead to appropriate cellular responses.

The Morphology of Craters on Mercury: Results from MESSENGER Flybys

Science.gov (United States)

Barnouin, Oliver S.; Zuber, Maria T.; Smith, David E.; Neumann, Gregory A.; Herrick, Robert R.; Chappelow, John E.; Murchie, Scott L.; Prockter, Louise M.

2012-01-01

Topographic data measured from the Mercury Laser Altimeter (MLA) and the Mercury Dual Imaging System (MDIS) aboard the MESSENGER spacecraft were used for investigations of the relationship between depth and diameter for impact craters on Mercury. Results using data from the MESSENGER flybys of the innermost planet indicate that most of the craters measured with MLA are shallower than those previously measured by using Mariner 10 images. MDIS images of these same MLA-measured craters show that they have been modified. The use of shadow measurement techniques, which were found to be accurate relative to the MLA results, indicate that both small bowl-shaped and large complex craters that are fresh possess depth-to-diameter ratios that are in good agreement with those measured from Mariner 10 images. The preliminary data also show that the depths of modified craters are shallower relative to fresh ones, and might provide quantitative estimates of crater in-filling by subsequent volcanic or impact processes. The diameter that defines the transition from simple to complex craters on Mercury based on MESSENGER data is consistent with that reported from Mariner 10 data.

Geomagnetic response to solar and interplanetary disturbances

Czech Academy of Sciences Publication Activity Database

Saiz, E.; Cerrato, Y.; Cid, C.; Dobrica, V.; Hejda, Pavel; Nenovski, P.; Stauning, P.; Bochníček, Josef; Danov, D.; Demetrescu, C.; Gonzalez, W. D.; Maris, G.; Teodosiev, D.; Valach, F.

2013-01-01

Roč. 3, July (2013), A26/1-A26/20 ISSN 2115-7251 R&D Projects: GA MŠk OC09070 Institutional support: RVO:67985530 Keywords : solar activity * interplanetary medium * indices * ionosphere (general) * ring current Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 2.519, year: 2013

Mercury's Solar Wind Interaction as Characterized by Magnetospheric Plasma Mantle Observations With MESSENGER

Science.gov (United States)

Jasinski, Jamie M.; Slavin, James A.; Raines, Jim M.; DiBraccio, Gina A.

2017-12-01

We analyze 94 traversals of Mercury's southern magnetospheric plasma mantle using data from the MESSENGER spacecraft. The mean and median proton number densities in the mantle are 1.5 and 1.3 cm-3, respectively. For sodium number density these values are 0.004 and 0.002 cm-3. Moderately higher densities are observed on the magnetospheric dusk side. The mantle supplies up to 1.5 × 108 cm-2 s-1 and 0.8 × 108 cm-2 s-1 of proton and sodium flux to the plasma sheet, respectively. We estimate the cross-electric magnetospheric potential from each observation and find a mean of 19 kV (standard deviation of 16 kV) and a median of 13 kV. This is an important result as it is lower than previous estimations and shows that Mercury's magnetosphere is at times not as highly driven by the solar wind as previously thought. Our values are comparable to the estimations for the ice giant planets, Uranus and Neptune, but lower than Earth. The estimated potentials do have a very large range of values (1-74 kV), showing that Mercury's magnetosphere is highly dynamic. A correlation of the potential is found to the interplanetary magnetic field (IMF) magnitude, supporting evidence that dayside magnetic reconnection can occur at all shear angles at Mercury. But we also see that Mercury has an Earth-like magnetospheric response, favoring -BZ IMF orientation. We find evidence that -BX orientations in the IMF favor the southern cusp and southern mantle. This is in agreement with telescopic observations of exospheric emission, but in disagreement with modeling.

Nitric oxide: a physiologic messenger.

Science.gov (United States)

Lowenstein, C J; Dinerman, J L; Snyder, S H

1994-02-01

To review the physiologic role of nitric oxide, an unusual messenger molecule that mediates blood vessel relaxation, neurotransmission, and pathogen suppression. A MEDLINE search of articles published from 1987 to 1993 that addressed nitric oxide and the enzyme that synthesizes it, nitric oxide synthase. Animal and human studies were selected from 3044 articles to analyze the clinical importance of nitric oxide. Descriptions of the structure and function of nitric oxide synthase were selected to show how nitric oxide acts as a biological messenger molecule. Biochemical and physiologic studies were analyzed if the same results were found by three or more independent observers. Two major classes of nitric oxide synthase enzymes produce nitric oxide. The constitutive isoforms found in endothelial cells and neurons release small amounts of nitric oxide for brief periods to signal adjacent cells, whereas the inducible isoform found in macrophages releases large amounts of nitric oxide continuously to eliminate bacteria and parasites. By diffusing into adjacent cells and binding to enzymes that contain iron, nitric oxide plays many important physiologic roles. It regulates blood pressure, transmits signals between neurons, and suppresses pathogens. Excess amounts, however, can damage host cells, causing neurotoxicity during strokes and causing the hypotension associated with sepsis. Nitric oxide is a simple molecule with many physiologic roles in the cardiovascular, neurologic, and immune systems. Although the general principles of nitric oxide synthesis are known, further research is necessary to determine what role it plays in causing disease.

Mercury's Sodium Exosphere: Observations during the MESSENGER Orbital Phase

Science.gov (United States)

Killen, Rosemary M.; Cassidy, Timothy A.; Vervack, Ronald J., Jr.; Burger, Matthew H.; Merkel, Aimee W.; Sarantos, Menelaos; Sprague, Ann L.; McClintock, William E.; Benna, Mehdi; Solomon, Sean C.

2012-01-01

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft entered into orbit about Mercury on March 18,2011. We now have approximately five Mercury years of data from orbit. Prior to the MESSENGER mission, Mercury's surface-bounded exosphere was known to contain H, He, Na. K, and Ca. The Ultraviolet and Visible Spectrometer (UVVS) began routine orbital observations of both the dayside and nightside exosphere on March 29. 2011, measuring altitude profiles for all previously detected neutral species except for He and K. We focus here on what we have learned about the sodium exosphere: its spatial, seasonal, and sporadic variation. Observations to date permit delineation of the relative roles of photon-stimulated desorption (PSD) and impact vaporization (IV) from seasonal and spatial effects, as well as of the roles of ions both as sputtering agents and in their possible role to enhance the efficiency of PSD. Correlations of Mercury's neutral sodium exosphere with measurements from MESSENGER's Magnetometer (MAG) and Energetic Particle and Plasma Spectrometer (EPPS) provide insight into the roles of ions and electrons. Models incorporating MAG observations provide a basis for identifying the location and area of the surface exposed to solar wind plasma, and EPPS observations reveal episodic populations of energetic electrons in the magnetosphere and the presence of planetary He(+), 0(+), and Na(+),

The cause of high-intensity long-duration continuous AE activity (HILDCAAS): interplanetary Alfven wave trains

International Nuclear Information System (INIS)

Tsurutani, B.T.; Gonzalez, W.D.

1987-01-01

It is shown that high intensity (AE > 1,000 nT), long duration (T > 2 d) continuous auroral activity (HILDCAA) events are caused by outward (from the sun) propagating interplanetary Alfven wave trains. The Alfven waves are often (but not always) detected several days after major interplanetary events, such as shocks and solar wind density enhancements. Presumably magnetic reconnection between the southward components of the Alfven wave magnetic fields and magnetospheric fields is the mechanism for transfer of solar wind energy to the magnetosphere. If the stringent requirements for HILDCAA events are relaxed, there are many more AE events of this type. A brief inspection indicates that these are also related to interplanetary Alfvenic fluctuations. We therefore suggest that most auroral activity may be caused by reconnection associated with Alfven waves in the interplanetary medium. (author)

Radar Characterization of the Interplanetary Meteoroid Environment, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — We propose a new modeling effort that will make substantial refinements and improvements to our existing models of the interplanetary meteoroid environment near...

Instant messenger-facilitated knowledge sharing and team performance

NARCIS (Netherlands)

Ou, C.X.J.; Davison, R.M.; Leung, D.

2014-01-01

The instant messenger (IM) is frequently encountered as a facilitator of communication in both social and working contexts. Nevertheless, there are concerns about the extent to which IMs bring organizational benefits, thereby overcoming interruptions to work. In this study, we focus on how IM tools

Primary structure of the α-subunit of Na+, K+-ATPase. II. Isolation, reverse transcription, and cloning of messenger RNA

International Nuclear Information System (INIS)

Petrukhin, K.E.; Broude, N.E.; Arsenyan, S.G.; Grishin, A.V.; Dzhandzhugazyan, K.N.; Modyanov, N.N.

1986-01-01

The messenger RNA coding the α-subunit of Na + ,K + -ATPase has been isolated from the outer medullary layer of porcine kidneys. The mRNA gives a specific hybridization band in the 25S-26S region with three oligonucleotide probes synthesized on the basis of information on the structure of three peptides isolated from a tryptic hydrolyzate of the α-subunit of Na + ,K + -ATPase. The translation of the mRNA in Xenopus laevis oocytes followed by immunochemical identification of the products of synthesis confirmed the presence of the mRNA of the α-subunit of Na + ,K + -ATPase in an enriched fraction of poly(A + )-RNA. This preparation has been used for the synthesis of cloning of double-stranded cDNA

Optimal and fast E/B separation with a dual messenger field

Science.gov (United States)

Kodi Ramanah, Doogesh; Lavaux, Guilhem; Wandelt, Benjamin D.

2018-05-01

We adapt our recently proposed dual messenger algorithm for spin field reconstruction and showcase its efficiency and effectiveness in Wiener filtering polarized cosmic microwave background (CMB) maps. Unlike conventional preconditioned conjugate gradient (PCG) solvers, our preconditioner-free technique can deal with high-resolution joint temperature and polarization maps with inhomogeneous noise distributions and arbitrary mask geometries with relative ease. Various convergence diagnostics illustrate the high quality of the dual messenger reconstruction. In contrast, the PCG implementation fails to converge to a reasonable solution for the specific problem considered. The implementation of the dual messenger method is straightforward and guarantees numerical stability and convergence. We show how the algorithm can be modified to generate fluctuation maps, which, combined with the Wiener filter solution, yield unbiased constrained signal realizations, consistent with observed data. This algorithm presents a pathway to exact global analyses of high-resolution and high-sensitivity CMB data for a statistically optimal separation of E and B modes. It is therefore relevant for current and next-generation CMB experiments, in the quest for the elusive primordial B-mode signal.

Dissection of the couplings between cellular messengers and the circadian clock

International Nuclear Information System (INIS)

Tong Jian; Edmunds, L.N.

1995-12-01

It has been known in recent years that living cells can exhibit circadian rhythms in totally different physiological processes. Intracellular messengers were demonstrated to mediate the entrained pathways linking rhythmic components between circadian clock and its output signalling. Levels of cyclic AMP and cyclic GMP in synchronized cells, and activities of the two key enzymes (AC and PDE) responsible for the cyclic AMP metabolism were measured by applying the isotopic techniques. Bimodal circadian oscillations of the messenger levels and the enzyme activities were disclosed in LD: 12, 12 cycle and constant darkness, as well as in the dividing and non-dividing cultures of the Euglena ZC mutant. Interference experiments with the enzyme activator and inhibitor such as forskolin, 8-Br-cGMP and LY 83583, and analysis of the cell division cycle (CDC) and coupling messengers suggested that the peak pulse of cyclic AMP, circadian oscillation of the AC-cAMP-PDE system and phase-dependent regulation by cyclic GMP might be important coupling factors in downstream mediation between the circadian clock and the CDC. (7 figs.)

Realising effective theories of tribrid inflation: are there effects from messenger fields?

International Nuclear Information System (INIS)

Antusch, Stefan; Nolde, David

2015-01-01

Tribrid inflation is a variant of supersymmetric hybrid inflation in which the inflaton is a matter field (which can be charged under gauge symmetries) and inflation ends by a GUT-scale phase transition of a waterfall field. These features make tribrid inflation a promising framework for realising inflation with particularly close connections to particle physics. Superpotentials of tribrid inflation involve effective operators suppressed by some cutoff scale, which is often taken as the Planck scale. However, these operators may also be generated by integrating out messenger superfields with masses below the Planck scale, which is in fact quite common in GUT and/or flavour models. The values of the inflaton field during inflation can then lie above this mass scale, which means that for reliably calculating the model predictions one has to go beyond the effective theory description. We therefore discuss realisations of effective theories of tribrid inflation and specify in which cases effects from the messenger fields are expected, and under which conditions they can safely be neglected. In particular, we point out how to construct realisations where, despite the fact that the inflaton field values are above the messenger mass scale, the predictions for the observables are (to a good approximation) identical to the ones calculated in the effective theory treatment where the messenger mass scale is identified with the (apparent) cutoff scale

Realising effective theories of tribrid inflation: are there effects from messenger fields?

Science.gov (United States)

Antusch, Stefan; Nolde, David

2015-09-01

Tribrid inflation is a variant of supersymmetric hybrid inflation in which the inflaton is a matter field (which can be charged under gauge symmetries) and inflation ends by a GUT-scale phase transition of a waterfall field. These features make tribrid inflation a promising framework for realising inflation with particularly close connections to particle physics. Superpotentials of tribrid inflation involve effective operators suppressed by some cutoff scale, which is often taken as the Planck scale. However, these operators may also be generated by integrating out messenger superfields with masses below the Planck scale, which is in fact quite common in GUT and/or flavour models. The values of the inflaton field during inflation can then lie above this mass scale, which means that for reliably calculating the model predictions one has to go beyond the effective theory description. We therefore discuss realisations of effective theories of tribrid inflation and specify in which cases effects from the messenger fields are expected, and under which conditions they can safely be neglected. In particular, we point out how to construct realisations where, despite the fact that the inflaton field values are above the messenger mass scale, the predictions for the observables are (to a good approximation) identical to the ones calculated in the effective theory treatment where the messenger mass scale is identified with the (apparent) cutoff scale.

Realising effective theories of tribrid inflation: are there effects from messenger fields?

Energy Technology Data Exchange (ETDEWEB)

Antusch, Stefan [Department of Physics, University of Basel,Klingelbergstr. 82, CH-4056 Basel (Switzerland); Max-Planck-Institut für Physik (Werner-Heisenberg-Institut),Föhringer Ring 6, D-80805 München (Germany); Nolde, David [Department of Physics, University of Basel,Klingelbergstr. 82, CH-4056 Basel (Switzerland)

2015-09-22

Tribrid inflation is a variant of supersymmetric hybrid inflation in which the inflaton is a matter field (which can be charged under gauge symmetries) and inflation ends by a GUT-scale phase transition of a waterfall field. These features make tribrid inflation a promising framework for realising inflation with particularly close connections to particle physics. Superpotentials of tribrid inflation involve effective operators suppressed by some cutoff scale, which is often taken as the Planck scale. However, these operators may also be generated by integrating out messenger superfields with masses below the Planck scale, which is in fact quite common in GUT and/or flavour models. The values of the inflaton field during inflation can then lie above this mass scale, which means that for reliably calculating the model predictions one has to go beyond the effective theory description. We therefore discuss realisations of effective theories of tribrid inflation and specify in which cases effects from the messenger fields are expected, and under which conditions they can safely be neglected. In particular, we point out how to construct realisations where, despite the fact that the inflaton field values are above the messenger mass scale, the predictions for the observables are (to a good approximation) identical to the ones calculated in the effective theory treatment where the messenger mass scale is identified with the (apparent) cutoff scale.

Comparing Strategies for Health Information Dissemination: Messengers That Can Help or Hinder.

Science.gov (United States)

Fishman, Jessica; Greenberg, Patricia; Bagga, Margy Barbieri; Casarett, David; Propert, Kathleen

2018-05-01

To test the effects of different messengers on the dissemination of health information. An experimental study exposed participants to 12 news articles pertaining to 1 of 3 health topics framed from the perspective of 4 generic messengers: religious figures, doctors, celebrity patients, or ordinary patients. Participants select as many of the 12 articles as desired. A cancer clinic within a large, urban hospital serving a sociodemographically diverse patient population. Eighty-nine patients with a history of cancer. The primary outcome was the frequency with which each news story was selected. Summary statistics and a general estimating equation model. For each health topic, news articles using celebrity messengers were the least likely to be selected; almost half of the participants (36 [41.4%] of 87) rejected all such articles. Articles linked to religious figures were equally unpopular ( P = .59). Articles that used doctors or ordinary patients as the messenger were very likely to be selected: Nearly all women (84 [96.6%] of 87) selected at least one of these. Furthermore, the odds of choosing articles linked to celebrities or religious leaders were statistically significantly lower than the odds of choosing those linked to ordinary patients or doctors ( P dissemination of information. Health materials linked to celebrities or religious figures were consistently less likely to be selected than those linked to ordinary patients, or doctors.

Effects of the foliar-applied protein "Harpin(Ea)" (messenger) on tomatoes infected with Phytophthora infestans.

Science.gov (United States)

Fontanilla, M; Montes, M; De Prado, R

2005-01-01

The active ingredient in Messenger, is Harpin(Ea), a naturally occurring protein derived from Erwinia amylovora, a causal agent of fire blight. When Messenger is applied to a plant, the protein Harpin(Ea) binds foliar receptors to it. The receptors recognize the presence of Harpin(Ea), sending a signal that a pathogen is present, actually "tricking" the plant into thinking that it is under attack. This binding process triggers a cascade of responses affecting a global change of gene expressions, stimulating several distinct biochemical pathways within the plant responsible for growth and disease and insect resistance. The objective of this work is to characterize the development of an induced resistance against Phytophthora infestans. No effective treatment is currently available against this pathogenic agent, which causes the loss of complete harvests of different crops. Tomato plants with and without Messenger applications were inoculated with Phytophthora infestans in the same way. In addition, some plants with and without Messenger applications were not inoculated. Inoculated plants were symptomatologically checked for local and systemic symptoms. Evaluations of the number of tomatoes produced, with or without damage, and their growth, were also carried out. Based on the data obtained from the assays, significant changes were observed in the parameters measured due to Messenger treatment. The severe damage of this disease was reduced in the plants which received Messenger applications. These results open up new pathways in the control of diseases like Phytophthora infestans, in which effective means to combat them still do not exist, or these means are harmful to the environment.

Optimizing Materials for Energy Harvesting on Interplanetary Return Missions

Data.gov (United States)

National Aeronautics and Space Administration — Manned interplanetary missions will only be desirable once the ability to return is established. Even using improved fuel technologies we have not resourced the fuel...

A fast-response two-photon fluorescent probe for imaging endogenous H2O2 in living cells and tissues

Science.gov (United States)

Lu, Yanan; Shi, Xiaomin; Fan, Wenlong; Black, Cory A.; Lu, Zhengliang; Fan, Chunhua

2018-02-01

As a second messenger, hydrogen peroxide plays significant roles in numerous physiological and pathological processes and is related to various diseases including inflammatory disease, diabetes, neurodegenerative disorders, cardiovascular disease and Alzheimer's disease. Two-photon (TP) fluorescent probes reported for the detection of endogenous H2O2 are rare and most have drawbacks such as slow response and low sensitivity. In this report, we demonstrate a simple H2O2-specific TP fluorescent probe (TX-HP) containing a two-photon dye 6-hydroxy-2,3,4,4a-tetrahydro-1H-xanthen-1-one (TX) on the modulation of the ICT process. The probe exhibits a rapid fluorescent response to H2O2 in 9 min with both high sensitivity and selectivity. The probe can detect exogenous H2O2 in living cells. Furthermore, the probe is successfully utilized for imaging H2O2 in liver tissues.

Early MESSENGER Results for Less Abundant or Weakly Emitting Species in Mercury's Exosphere

Science.gov (United States)

Vervack, Ronald J., Jr.; McClintock, William E.; Killen, Rosemary M.; Sprague, Ann L.; Burger, Matthew H.; Merkel, Aimee W.; Sarantos, Menelaos

2011-01-01

Now that the Messenger spacecraft is in orbit about Mercury, the extended observing time enables searches for exospheric species that are less abundant or weakly emitting compared with those for which emission has previously been detected. Many of these species cannot be observed from the ground because of terrestrial atmospheric absorption. We report here on the status of MESSENGER orbital-phase searches for additional species in Mercury's exosphere.

Twin probes for space geodesy

International Nuclear Information System (INIS)

Bertotti, B.

1978-01-01

The twin probe method, proposed by Bertotti and Colombo (1972) to get rid of nongravitational forces in interplanetary space, can be applied to a near-Earth orbit to eliminate the atmospheric drag. Two equal pairs of probes, each pair consisting of two passive, small and dense spheres of equal surface and different masses, are flown on a circular orbit at an altitude of about 300 km. Each pair determines the motion of an ideal point which feels only the gravitational forces. They are separated by a distance d of (100/200) km and are tracked from a spacecraft or the Space Shuttle, flying at the same altitude. The relative motion of the two ideal points is reconstructed and yields a measurement of the fine structure of the Earth gravitational field, corresponding to a harmonic order l approximately a/d (a is the radius of the Earth). The tracking can be done by laser ranging to the four spheres, covered by corner reflectors; Doppler ranging is more convenient for higher values of l and can also be used. The accuracy in the compensation of the non-gravitational forces and in the measurements one needs for a given l are discussed in detail. (author)

Interplanetary sources of magnetic storms: A statistical study

DEFF Research Database (Denmark)

Vennerstrøm, Susanne

2001-01-01

Magnetic storms are mainly caused by the occurrence of intense southward magnetic fields in the interplanetary medium. These fields can be formed directly either by ejection of magnetic structures from the Sun or by stream interaction processes during solar wind propagation. In the present study we...... examine 30 years of satellite measurement of the solar wind during magnetic storms, with the aim of estimating the relative importance of these two processes. We use the solar wind proton temperature relative to the temperature expected from the empirical relation to the solar wind speed T......-p/T-exp, together with the speed gradient, and the interplanetary magnetic field azimuth in the ecliptic, in order to distinguish between the two processes statistically. We find that compression due to stream interaction is at least as important as the direct effect of ejection of intense fields, and probably more...

Interplanetary sources to magnetic storms - A statistical study

DEFF Research Database (Denmark)

Vennerstrøm, Susanne

2001-01-01

Magnetic storms are mainly caused by the occurrence of intense southward magnetic fields in the interplanetary medium. These fields can be formed directly either by ejection of magnetic structures from the Sun or by stream interaction processes during solar wind propagation. In the present study we...... examine 30 years of satellite measurement of the solar wind during magnetic storms, with the aim of estimating the relative importance of these two processes. We use the solar wind proton temperature relative to the temperature expected from the empirical relation to the solar wind speed Tp/Texp, together...... with the speed gradient, and the interplanetary magnetic field azimuth in the ecliptic, in order to distinguish between the two processes statistically. We find that compression due to stream interaction is at least as important as the direct effect of ejection of intense fields, and probably more so. Only...

GEO Debris and Interplanetary Dust: Fluxes and Charging Behavior

Science.gov (United States)

Graps, A. L.; Green, S. F.; McBride, N. M.; McDonnell, J. A. M.; Drolshagen, G.; Svedhem, H.; Bunte, K. D.

2005-08-01

A population of cosmic dust mixed with a population of man-made debris exists within the Earth's magnetosphere. Measurements of these provide the data samples for studies of the interplanetary dust particles that travel through our magnetosphere from the outside and for studies of the local byproducts of our space endeavours. Even though instruments to detect natural meteoroids and space debris particles have been flown in Low Earth Orbits (LEO) and on interplanetary missions, very little information on the particle environment for Earth orbits above about 600 km altitude have been available. In particular, knowledge about particles smaller than 1 m in the geostationary (GEO) region was largely unknown before GORID. In September 1996, a dust/debris detector: GORID was launched into GEO as a piggyback instrument on the Russian Express-2 telecommunications spacecraft. The instrument began its normal operation in April 1997 and ended its mission in July 2002. The goal of this work was to use GORID's particle data to identify and separate the space debris from the interplanetary dust particles (IDPs) in GEO, to more finely determine the instrument's measurement characteristics and to derive impact fluxes. Here we present some results of that study. We give GORID flux distributions for debris and IDPs and then present intriguing debris clustering features that might be the result of electrostatic fragmentation of the rocket slag particles.

The Crust of Mercury After the MESSENGER Gravity Investigation

Science.gov (United States)

Mazarico, E.; Genova, A.; Goossens, S.; Neumann, G. A.; Smith, D. E.; Zuber, M. T.

2018-05-01

We present the results of an improved analysis of the entire MESSENGER radio tracking dataset to derive key geophysical parameters of Mercury such as its gravity field. In particular, we derive and interpret a new crustal thickness model.

An Investigation of Interplanetary Structures for Solar Cycles 23 and 24 and their Space Weather Consequences.

Science.gov (United States)

Sultan, M. S.; Jules, A.; Marchese, P.; Damas, M. C.

2017-12-01

It is crucial to study space weather because severe interplanetary conditions can cause geomagnetic storms that may damage both space- and ground-based technological systems such as satellites, communication systems, and power grids. Interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs) are the primary drivers of geomagnetic storms. As they travel through interplanetary space and reach geospace, their spatial structures change which can result in various geomagnetic effects. Therefore, studying these drivers and their structures is essential in order to better understand and mitigate their impact on technological systems, as well as to forecast geomagnetic storms. In this study, over 150 storms were cross-checked for both solar cycles (SC) 23 and 24. This data has revealed the most common interplanetary structures, i.e., sheath (Sh); magnetic cloud following a shock front (sMC); sheath region and magnetic cloud (Sh/MC); and corotating interaction regions (CIRs). Furthermore, plasma parameters as well as variation in the intensity and duration of storms resulting from different interplanetary structures are studied for their effect on geomagnetically induced currents (GICs), as well as for their effect on power grids. Although preliminary results for SC 23 indicate that storm intensity may play a dominant role for GICs, duration might also be a factor, albeit smaller. Results from both SC 23 and 24 are analyzed and compared, and should lead to an enhanced understanding of space weather consequences of interplanetary structures and their possible forecasting.

Insights into the Nature of Mercury's Exosphere: Early Results from the MESSENGER Orbital Mission Phase

Science.gov (United States)

McClintock, William E.; Burger, Matthew H.; Killen, Rosemary M.; Merkel, Aimee W.; Sarantos, Menelaos; Sprague, Ann L.; Solomon, Sean C.; Vervack, Ronald J., Jr.

2011-01-01

The Ultraviolet and Visible Spectrometer aboard the MESSENGER spacecraft has been making routine observations of Mercury's exosphere since March 29, 2011. Correlations of the spatial distributions of Ca, Mg, and Na with MESSENGER magnetic field and energetic particle distribution data provide insight into the processes that populate the neutral exosphere

On-Orbit Verification of Luminance Based Target Tracking and Faint Body Extractions by a Small Telescope on the World's First Micro-Interplanetary Space Probe

OpenAIRE

Ariu, Kaito; Ikari, Satoshi; Kawabata, Yosuke; Nagata, Kazutaka; Matsuguma, Toshihiro; Inamori, Takaya; Miyamura, Norihide; Funase, Ryu; Nakasuka, Shinichi

2016-01-01

In recent years, low cost and quick development of very small satellites ranging from CubeSats of 1 kg to micro-satellites of approximately 50 kg have allowed advances in space development and application. Although most of these satellites are in Earth orbits, a small spacecraft for deep-space missions has been developed and launched for the first time in the world. The Proximate Object Close Flyby with Optical Navigation (PROCYON) micro-interplanetary spacecraft, developed by the University ...

Preentry communication design elements for outer planets atmospheric entry probe

Science.gov (United States)

1976-01-01

Four related tasks are discussed for data transmission from a probe prior to entering the atmosphere of Jupiter to an orbiting spacecraft in a trajectory past the planet: (1) link analysis and design; (2) system conceptual design; (3) Doppler measurement analysis; and (4) an electronically despun antenna. For tasks 1, 3, and 4, an analytical approach was developed and combined with computational capability available to produce quantitative results corresponding to requirements and constraints given by NASA, ARC. One constraint having a major impact on the numerical results of the link analysis was the assumption of a nonsteerable antenna on a spinning orbiter. Other constraints included the interplanetary trajectory and the approach trajectory. Because the Jupiter Orbiter Probe (JOP) program is currently in a state of evolution, all requirements and constraints applied during this study are subject to change. However, the relationships of parameters as developed will remain valid and will aid in planning Jupiter missions.

Correlation of variations of charged particle fluxes in the flare on 3 November, 1973 with change of parameters of interplanetary medium according to the data of the ''Mars-7'' automatic interplanetary station and ''Prognoz-3'' artificial Earth's satellite

International Nuclear Information System (INIS)

Kuzhevskij, B.M.; Mineev, Yu.V.; Savenko, I.A.; Spir'kova, E.S.; Surova, G.M.; ShestopaloV, I.P.

1979-01-01

The experimental data on the charged particle fluxes in the flare on the 3d of November, 1973 are analyzed. The experiments were carried out at the ''Prognoz-3'' artificial Earth satellite and ''Mars-7'' automatic interplanetary station with the help of devices recorded Esub(e) >= 30 keV energy electrons, 1 <= Esub(p) <= 5 MeV energy protons and 1-150 MeV energy protons. Presented are the data on variations of the intensity of cosmic ray particles which are compared with the data on interplanetary magnetic fields. The character of proton and electron intensity variations is explained by the change of interplanetary medium parameters. It is supposed that the electron splashes and proton intensity variations recorded at the satellites are conditioned by the sign change of the interplanetary magnetic field

Ring Current Response to Different Storm Drivers. Van Allen Probes and Cluster Observations.

Science.gov (United States)

Bingham, S.; Mouikis, C.; Kistler, L. M.; Spence, H. E.; Gkioulidou, M.; Claudepierre, S. G.; Farrugia, C. J.

2015-12-01

The ring current responds differently to the different solar and interplanetary storm drivers such as coronal mass injections, (CME's), co-rotating interaction regions (CIR's), high-speed streamers and other structures. The resulting changes in the ring current particle pressure change the global magnetic field, which affects the transport of the radiation belts. In order to determine the field changes during a storm it is necessary to understand the transport, sources and losses of the particles that contribute to the ring current. The source population of the storm time ring current is the night side plasma sheet. However, it is not clear how these convecting particles affect the storm time ring current pressure development. We use Van Allen Probes and Cluster observations together with the Volland-Stern and dipole magnetic field models to determine the contribution in the ring current pressure of the plasma sheet particles convecting from the night side that are on open drift paths, during the storm evolution. We compare storms that are related to different interplanetary drivers, CME and CIR, as observed at different local times.

Mercury Conditions for the MESSENGER Mission Simulated in High- Solar-Radiation Vacuum Tests

Science.gov (United States)

Wong, Wayne A.

2003-01-01

The MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging) spacecraft, planned for launch in March 2004, will perform two flybys of Mercury before entering a year-long orbit of the planet in September 2009. The mission will provide opportunities for detailed characterization of the surface, interior, atmosphere, and magnetosphere of the closest planet to the Sun. The NASA Glenn Research Center and the MESSENGER spacecraft integrator, the Johns Hopkins University Applied Physics Laboratory, have partnered under a Space Act Agreement to characterize a variety of critical components and materials under simulated conditions expected near Mercury. Glenn's Vacuum Facility 6, which is equipped with a solar simulator, can simulate the vacuum and high solar radiation anticipated in Mercury orbit. The MESSENGER test hardware includes a variety of materials and components that are being characterized during the Tank 6 vacuum tests, where the hardware will be exposed to up to 11 suns insolation, simulating conditions expected in Mercury orbit. In 2002, ten solar vacuum tests were conducted, including beginning of life, end of life, backside exposure, and solar panel thermal shock cycling tests. Components tested include candidate solar array panels, sensors, thermal shielding materials, and communication devices. As an example, for the solar panel thermal shock cycling test, two candidate solar array panels were suspended on a lift mechanism that lowered the panels into a liquid-nitrogen-cooled box. After reaching -140 C, the panels were then lifted out of the box and exposed to the equivalent of 6 suns (8.1 kilowatts per square meters). After five cold soak/heating cycles were completed successfully, there was no apparent degradation in panel performance. An anticipated 100-hr thermal shield life test is planned for autumn, followed by solar panel flight qualification tests in winter. Glenn's ongoing support to the MESSENGER program has been instrumental in

Coronal mass ejection hits mercury: A.I.K.E.F. hybrid-code results compared to MESSENGER data

Science.gov (United States)

Exner, W.; Heyner, D.; Liuzzo, L.; Motschmann, U.; Shiota, D.; Kusano, K.; Shibayama, T.

2018-04-01

Mercury is the closest orbiting planet around the sun and is therefore embedded in an intensive and highly varying solar wind. In-situ data from the MESSENGER spacecraft of the plasma environment near Mercury indicates that a coronal mass ejection (CME) passed the planet on 23 November 2011 over the span of the 12 h MESSENGER orbit. Slavin et al. (2014) derived the upstream parameters of the solar wind at the time of that orbit, and were able to explain the observed MESSENGER data in the cusp and magnetopause segments of MESSENGER's trajectory. These upstream parameters will be used for our first simulation run. We use the hybrid code A.I.K.E.F. which treats ions as individual particles and electrons as a mass-less fluid, to conduct hybrid simulations of Mercury's magnetospheric response to the impact of the CME on ion gyro time scales. Results from the simulation are in agreement with magnetic field measurements from the inner day-side magnetosphere and the bow-shock region. However, at the planet's nightside, Mercury's plasma environment seemed to be governed by different solar wind conditions, in conclusion, Mercury's interaction with the CME is not sufficiently describable by only one set of upstream parameters. Therefore, to simulate the magnetospheric response while MESSENGER was located in the tail region, we use parameters obtained from the MHD solar wind simulation code SUSANOO (Shiota et al. (2014)) for our second simulation run. The parameters of the SUSANOO model achieve a good agreement of the data concerning the plasma tail crossing and the night-side approach to Mercury. However, the polar and closest approach are hardly described by both upstream parameters, namely, neither upstream dataset is able to reproduce the MESSENGER crossing of Mercury's magnetospheric cusp. We conclude that the respective CME was too variable on the timescale of the MESSENGER orbit to be described by only two sets of upstream conditions. Our results suggest locally strong

Coulomb interactions between cytoplasmic electric fields and phosphorylated messenger proteins optimize information flow in cells.

Directory of Open Access Journals (Sweden)

Robert A Gatenby

2010-08-01

Full Text Available Normal cell function requires timely and accurate transmission of information from receptors on the cell membrane (CM to the nucleus. Movement of messenger proteins in the cytoplasm is thought to be dependent on random walk. However, Brownian motion will disperse messenger proteins throughout the cytosol resulting in slow and highly variable transit times. We propose that a critical component of information transfer is an intracellular electric field generated by distribution of charge on the nuclear membrane (NM. While the latter has been demonstrated experimentally for decades, the role of the consequent electric field has been assumed to be minimal due to a Debye length of about 1 nanometer that results from screening by intracellular Cl- and K+. We propose inclusion of these inorganic ions in the Debye-Huckel equation is incorrect because nuclear pores allow transit through the membrane at a rate far faster than the time to thermodynamic equilibrium. In our model, only the charged, mobile messenger proteins contribute to the Debye length.Using this revised model and published data, we estimate the NM possesses a Debye-Huckel length of a few microns and find this is consistent with recent measurement using intracellular nano-voltmeters. We demonstrate the field will accelerate isolated messenger proteins toward the nucleus through Coulomb interactions with negative charges added by phosphorylation. We calculate transit times as short as 0.01 sec. When large numbers of phosphorylated messenger proteins are generated by increasing concentrations of extracellular ligands, we demonstrate they generate a self-screening environment that regionally attenuates the cytoplasmic field, slowing movement but permitting greater cross talk among pathways. Preliminary experimental results with phosphorylated RAF are consistent with model predictions.This work demonstrates that previously unrecognized Coulomb interactions between phosphorylated messenger

The models evaluating courier and messenger companies in Poland

Directory of Open Access Journals (Sweden)

Chodakowska Ewa

2016-12-01

Full Text Available Data Envelopment Analysis (DEA is a well-established, popular, and often used method for efficiency evaluation of units from all sector, both commercial and non-profit organisations, of any scale of operations. Network DEA models are a relatively recent approach used to examine the efficiency of decision-making units (DMUs having an internal structure of sub-processes. The article presents the concept of DEA network models in estimating the efficiency of courier and messenger companies with relations to their business clients. The considerations are supported by an example of data concerning leaders from the sector of couriers and messengers in Poland and one of the biggest and most popular online stores. The results are compared with the traditional DEA approach. In addition, to measure reliability for DEA scores, the jackknife procedure was performed. The author proves the usefulness of network DEA as a research and management tool.

Implementing a Near-Optimal Optical Receiver for Inter-Planetary Communication

Data.gov (United States)

National Aeronautics and Space Administration — Proposal Objective: Interplanetary communications signals are inherently weak at the receiver. In fact, for a desired data rate the received optical pulses may...

Fast, Autonomous Chemical Interplanetary Mission Design via Hybrid Optimal Control

Data.gov (United States)

National Aeronautics and Space Administration — Interplanetary mission design is historically a complex and expensive process requiring many human-hours of work. This proposal outlines a novel technique for...

Dashboard Monitoring System Berbasis Web Sebagai Pemantau Layanan liteBIG Instant Messenger

Directory of Open Access Journals (Sweden)

Gigih Forda Nama

2017-04-01

Full Text Available Saat ini hampir semua pengguna ponsel pintar menggunakan layanan perpesanan instan sebagai media komunikasi dikarenakan layanan perpesanan instan lebih hemat biaya dengan hanya menggunakan jaringan internet dibandingkan layanan pesan singkat (SMS. Layanan yang diberikan harus dapat melayani pengguna dengan baik agar pesan yang dikirim oleh pengirim dapat diterima oleh penerima dengan cepat dan akurat. Layanan ini juga harus dijaga keandalannya untuk menjamin kualitas pelayanan dan untuk menghindari ketidaknyamanan pengguna. Sehingga, diperlukan adanya sistem pemantauan berupa perangkat lunak untuk pengawasan status layanan setiap saat dapat diakses dari manapun dan kapanpun. PT.Sandika Cahaya Mandiri memiliki produk layanan perpesanan instan dengan brand name liteBIG Messenger. Perusahaan ini memerlukan perangkat lunak untuk pemantauan layanan liteBIG Messenger. Dengan adanya perangkat lunak pemantauan layanan, petugas pemantauan dapat melihat secara realtime status layanan utama pada setiap komputer server, pemakaian sumber daya (cpu, memory, dan harddisk, dan statistik pengguna baru liteBIG Messenger  melalui antarmuka web. Petugas pemantauan juga akan mendapat pemberitahuan ketika terjadi masalah pada layanan sehingga masalah dapat lebih dini diketahui dan downtime dapat dikurangi.

Interplanetary and lunar surface SP-100 nuclear power applications

International Nuclear Information System (INIS)

Josloff, A.T.; Shepard, N.F.; Smith, M.; Stephen, J.D.

1992-01-01

This paper describes how the SP-100 Space Reactor Power System (SRPS) can be tailored to meet the specific requirements for a lunar surface power system to meet the needs of the consolidation and utilization phases outlined in the 90-day NASA SEI study report. This same basic power system can also be configured to obtain the low specific masses needed to enable robotic interplanetary science missions employing Nuclear Electric Propulsion (NEP). In both cases it is shown that the SP-100 SRPS can meet the specific requirements. For interplanetary NEP missions, performance upgrades currently being developed in the area of light weight radiators and improved thermoelectric material are assumed to be technology ready in the year 2000 time frame. For lunar applications, some system rearrangement and enclosure of critical components are necessary modifications to the present baseline design

The Energy Messenger, Number 1, Volume 4

International Nuclear Information System (INIS)

Stancil, J.

1995-01-01

'The Energy Messenger' is a Department of Energy publication on energy activities of interest to American Indians. The first issue of 1995 (in a magazine format) includes articles on: tribes winning grants to develop energy resources, recruiting of internships for DOE, information about Title XXVI-Indian Energy Resources, American Indian Heritage Month, tribal perspective on DOE actions, joint ventures between tribes and the DOE, and brief description of recent DOE activities

The Energy Messenger, Number 1, Volume 4

Energy Technology Data Exchange (ETDEWEB)

Stancil, J. [ed.

1995-01-01

`The Energy Messenger` is a Department of Energy publication on energy activities of interest to American Indians. The first issue of 1995 (in a magazine format) includes articles on: tribes winning grants to develop energy resources, recruiting of internships for DOE, information about Title XXVI-Indian Energy Resources, American Indian Heritage Month, tribal perspective on DOE actions, joint ventures between tribes and the DOE, and brief description of recent DOE activities.

IPS observations of transient interplanetary phenomena associated with solar filament activity in late august

International Nuclear Information System (INIS)

Watanabe, Takashi; Marubashi, Katsuhide.

1985-01-01

Large-scale structures of the solar wind plasma during the severe geomagnetic storm of August 27-29, 1978 are studied on the basis of IPS and spacecraft observations. Three-dimensional configuration of an interplanetary disturbance which caused the SSC of August 27, 1978 was an oblate sphere having an axial ratio of 1.7. Approximate excess mass and kinetic energy contained within the high-speed portion of the disturbance (--500 km s -1 ) were 10 16 g and 3 x 10 31 erg, respectively. An interplanetary disturbance was also observed on August 28, 1978 during the main phase of the geomagnetic storm. It is suggested that the solar-filament activity which took place near the solar disk center in August 23-25, 1978 caused these interplanetary disturbances. (author)

Dynamics of magnetic clouds in interplanetary space

International Nuclear Information System (INIS)

Yeh, T.

1987-01-01

Magnetic clouds observed in interplanetary space may be regarded as extraneous bodies immersed in the magnetized medium of the solar wind. The interface between a magnetic cloud and its surrounding medium separates the internal and external magnetic fields. Polarization currents are induced in the peripheral layer to make the ambient magnetic field tangential. The motion of a magnetic cloud through the interplanetary medium may be partitioned into a translational motion of the magnetic cloud as a whole and an expansive motion of the volume relative to the axis of the magnetic cloud. The translational motion is determined by two kinds of forces, i.e., the gravitational force exerted by the Sun, and the hydromagnetic buoyancy force exerted by the surrounding medium. On the other hand, the expansive motion is determined by the pressure gradient sustaining the gross difference between the internal and external pressures and by the self-induced magnetic force that results from the interaction among the internal currents. The force resulting from the internal and external currents is a part of the hydromagnetic buoyancy force, manifested by a thermal stress caused by the inhomogeneity of the ambient magnetic pressure

Dynamics of magnetic clouds in interplanetary space

Science.gov (United States)

Yeh, Tyan

1987-09-01

Magnetic clouds observed in interplanetary space may be regarded as extraneous bodies immersed in the magnetized medium of the solar wind. The interface between a magnetic cloud and its surrounding medium separates the internal and external magnetic fields. Polarization currents are induced in the peripheral layer to make the ambient magnetic field tangential. The motion of a magnetic cloud through the interplanetary medium may be partitioned into a translational motion of the magnetic cloud as a whole and an expansive motion of the volume relative to the axis of the magnetic cloud. The translational motion is determined by two kinds of forces, i.e., the gravitational force exerted by the Sun, and the hydromagnetic buoyancy force exerted by the surrounding medium. On the other hand, the expansive motion is determined by the pressure gradient sustaining the gross difference between the internal and external pressures and by the self-induced magnetic force that results from the interaction among the internal currents. The force resulting from the internal and external currents is a part of the hydromagnetic buoyancy force, manifested by a thermal stress caused by the inhomogeneity of the ambient magnetic pressure.

Commercially-driven human interplanetary propulsion systems: Rationale, concept, technology, and performance requirements

International Nuclear Information System (INIS)

Williams, C.H.; Borowski, S.K.

1996-01-01

Previous studies of human interplanetary missions are largely characterized by long trip times, limited performance capabilities, and enormous costs. Until these missions become dramatically more open-quote open-quote commercial-friendly close-quote close-quote, their funding source and rationale will be restricted to national governments and their political/scientific interests respectively. A rationale is discussed for human interplanetary space exploration predicated on the private sector. Space propulsion system requirements are identified for interplanetary transfer times of no more than a few weeks/months to and between the major outer planets. Nuclear fusion is identified as the minimum requisite space propulsion technology. A conceptual design is described and evolutionary catalyzed-DD to DHe 3 fuel cycles are proposed. Magnetic nozzles for direct thrust generation and quantifying the operational aspects of the energy exchange mechanisms between high energy reaction products and neutral propellants are identified as two of the many key supporting technologies essential to satisfying system performance requirements. Government support of focused, breakthrough technologies is recommended at funding levels appropriate to other ongoing federal research. copyright 1996 American Institute of Physics

Electron Dropout Echoes Induced by Interplanetary Shock: A Statistical Study

Science.gov (United States)

Liu, Z.; Zong, Q.; Hao, Y.; Zhou, X.; Ma, X.; Liu, Y.

2017-12-01

"Electron dropout echo" as indicated by repeated moderate dropout and recovery signatures of the flux of energetic electron in the out radiation belt region has been investigated systematically. The electron dropout and its echoes are usually found for higher energy (> 300 keV) channels fluxes, whereas the flux enhancements are obvious for lower energy electrons simultaneously after the interplanetary shock arrives at the Earth's geosynchronous orbit. 104 dropout echo events have been found from 215 interplanetary shock events from 1998 to 2007 based on LANL satellite data. In analogy to substorm injections, these 104 events could be naturally divided into two categories: dispersionless (49 events) or dispersive (55 events) according to the energy dispersion of the initial dropout. It is found that locations of dispersionless events are distributed mainly in the duskside magnetosphere. Further, the obtained locations derived from dispersive events with the time-of-flight technique of the initial dropout regions are mainly located at the duskside as well. Statistical studies have shown that the effect of shock normal, interplanetary magnetic field Bz and solar wind dynamic pressure may be insignificant to these electron dropout events. We suggest that the electric field impulse induced by the IP shock produces a more pronounced inward migration of electrons at the dusk side, resulting in the observed dusk-side moderate dropout of electron flux and its consequent echoes.

Gravitational Waves and Multi-Messenger Astronomy

Science.gov (United States)

Centrella, Joan M.

2010-01-01

Gravitational waves are produced by a wide variety of sources throughout the cosmos, including the mergers of black hole and neutron star binaries/compact objects spiraling into central black holes in galactic nuclei, close compact binaries/and phase transitions and quantum fluctuations in the early universe. Observing these signals can bring new, and often very precise, information about their sources across vast stretches of cosmic time. In this talk we will focus on thee opening of this gravitational-wave window on the universe, highlighting new opportunities for discovery and multi-messenger astronomy.

Sodium ion exosphere of Mercury during MESSENGER flybys

Czech Academy of Sciences Publication Activity Database

Paral, Jan; Trávníček, Pavel M.; Rankin, R.; Schriver, D.

2010-01-01

Roč. 37, č. 19 (2010), L19102/1-L19102/5 ISSN 0094-8276 Institutional research plan: CEZ:AV0Z30420517; CEZ:AV0Z10030501 Keywords : MESSENGER flybys * solar wind sputtering * photo-stimulated desorption Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.505, year: 2010 http://onlinelibrary.wiley.com/doi/10.1029/2010GL044413/abstract

A study of the inferred interplanetary magnetic field polarity periodicities

International Nuclear Information System (INIS)

Xanthakis, J.; Tritakis, V.P.; Zerefos, Ch.

1981-01-01

A detailed Power Spectrum Analysis applied on the daily polarities of the inferred interplanetary magnetic field, published by Svalgaard, has pointed out that the main periodicity apparent in these data is 27-28 days, which suggests a recurrency of a 2-sector structure. There is also a secondary periodicity of 13-14 days which mainly appears in the yers of the descending branch of the solar cycle and superimposes on the 2-sector structure, transforming it into a 4-sector structure. A strict statistical study of the correlation between the predominant polarity of the interplanetary magnetic field and the heliographic latitude of the Earth, also known as the Rosenberg-Coleman effect, pointed out that perhaps there is a faint correspondence between these two elements, but one cannot speak of a systematic effect. (Auth.)

Quasi-linear theory and transport theory. [particle acceleration in interplanetary medium

Science.gov (United States)

Smith, Charles W.

1992-01-01

The theory of energetic particle scattering by magnetostatic fluctuations is reviewed in so far as it fails to produce the rigidity-independent mean-free-paths observed. Basic aspects of interplanetary magnetic field fluctuations are reviewed with emphasis placed on the existence of dissipation range spectra at high wavenumbers. These spectra are then incorporated into existing theories for resonant magnetostatic scattering and are shown to yield infinite mean-free-paths. Nonresonant scattering in the form of magnetic mirroring is examined and offered as a partial solution to the magnetostatic problem. In the process, mean-free-paths are obtained in good agreement with observations in the interplanetary medium at 1 AU and upstream of planetary bow shocks.

Modeling of ion acceleration through drift and diffusion at interplanetary shocks

Science.gov (United States)

Decker, R. B.; Vlahos, L.

1986-01-01

A test particle simulation designed to model ion acceleration through drift and diffusion at interplanetary shocks is described. The technique consists of integrating along exact particle orbits in a system where the angle between the shock normal and mean upstream magnetic field, the level of magnetic fluctuations, and the energy of injected particles can assume a range of values. The technique makes it possible to study time-dependent shock acceleration under conditions not amenable to analytical techniques. To illustrate the capability of the numerical model, proton acceleration was considered under conditions appropriate for interplanetary shocks at 1 AU, including large-amplitude transverse magnetic fluctuations derived from power spectra of both ambient and shock-associated MHD waves.

Mercury's Interior from MESSENGER Radio Science Data

Science.gov (United States)

Genova, A.; Mazarico, E.; Goossens, S. J.; Lemoine, F. G.; Neumann, G. A.; Smith, D. E.; Zuber, M. T.

2017-12-01

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft provided precise radio tracking data in orbit about Mercury for more than 4 years, from March 2011 to April 2015. These geodetic measurements enable us to investigate the interior structure of the planet from the inner core to the crust. The first three years of radio data allowed us to determine the gravity field of Mercury with a resolution of 150 km in the northern hemisphere (degree and order 50 in spherical harmonics) since the periapsis was located at higher latitudes (>65˚N) and 200-500 km altitudes. The comparison of this gravity solution with Mercury's topography, which was retrieved by using over 25 million individual measurements of the Mercury Laser Altimeter (MLA), resulted in a preliminary map of the crustal thickness of the planet. However, those results were limited by the resolution of the gravity field since the topography was defined in spherical harmonics up to degree and order 125. The last year of the MESSENGER extended mission was dedicated to a low-altitude campaign, where the spacecraft periapsis was maintained at altitudes between 25 and 100 km. The radio data collected during this mission phase allowed us to significantly improve the resolution of the gravity field locally in the northern hemisphere up to degree and order 100 in spherical harmonics. We present the gravity anomalies and crustal thickness maps that lead to a better understanding on the formation and evolution of specific regions. We present our estimated orientation model, which slightly differs from the solutions that were obtained by using Earth-based radar measurements and the co-registration of MESSENGER imaging and altimetry data. These previous estimates provide a direct measurement of the surface response, whereas the orientation model from gravity is more sensitive to the inner and outer core. A discrepancy between core and surface obliquities may provide fundamental

Detailed mapping of serotonin 5-HT{sub 1B} and 5-HT{sub 1D} receptor messenger RNA and ligand binding sites in guinea-pig brain and trigeminal ganglion: clues for function

Energy Technology Data Exchange (ETDEWEB)

Leysen, J.E. [Graduate School Neurosciences, Amsterdam (Netherlands); Schotte, A.; Jurzak, M.; Luyten, W.H.M.L. [Department of Biochemical Pharmacology, Janssen Research Foundation, Beerse (Belgium); Voorn, P.; Bonaventure, P. [Graduate School Neurosciences, Amsterdam (Netherlands)

1997-10-17

The similar pharmacology of the 5-HT{sub 1B} and 5-HT{sub 1D} receptors, and the lack of selective compounds sufficiently distinguishing between the two receptor subtypes, have hampered functional studies on these receptors. In order to provide clues for differential functional roles of the two subtypes, we performed a parallel localization study throughout the guinea-pig brain and the trigeminal ganglia by means of quantitative in situ hybridization histochemistry (using [{sup 35}S]-labelled riboprobes probes for receptor messenger RNA) and receptor autoradiography (using a new radioligand [{sup 3}H]alniditan).The anatomical patterns of 5-HT{sub 1B} and 5-HT{sub 1D} receptor messenger RNA were quite different. While 5-HT{sub 1B} receptor messenger RNA was abundant throughout the brain (with highest levels in the striatum, nucleus accumbens, olfactory tubercle, cortex, hypothalamus, hippocampal formation, amygdala, thalamus, dorsal raphe and cerebellum), 5-HT{sub 1D} receptor messenger RNA exhibited a more restricted pattern; it was found mainly in the olfactory tubercle, entorhinal cortex, dorsal raphe, cerebellum, mesencephalic trigeminal nucleus and in the trigeminal ganglion. The density of 5-HT{sub 1B/1D} binding sites (combined) obtained with [{sup 3}H]alniditan autoradiography was high in the substantia nigra, superior colliculus and globus pallidus, whereas lower levels were detected in the caudate-putamen, hypothalamus, hippocampal formation, amygdala, thalamus and central gray. This distribution pattern was indistinguishable from specific 5-HT{sub 1B} receptor labelling in the presence of ketanserin under conditions to occlude 5-HT{sub 1D} receptor labelling; hence the latter were below detection level. Relationships between the regional distributions of the receptor messenger RNAs and binding sites and particular neuroanatomical pathways are discussed with respect to possible functional roles of the 5-HT{sub 1B} and 5-HT{sub 1D} receptors. (Copyright (c

The effect of addiction to mobile messenger software and mental health among physical education students

Directory of Open Access Journals (Sweden)

Mostafa Bagherianfar

2017-08-01

Full Text Available Introduction: The objective of the present study is to the effect of addiction to mobile messenger software on mental health among physical education university students of Torbat-e-Heydarieh city.  Materials and Methods: The statistical population of this descriptive-correlational study included all physical education university students of Torbat-e-Heydarieh city. 169 students out of 302 were chosen as the sample of study, for which stratified sampling method was applied. In order to collect data, Goldberg general health questionnaire and addiction to mobile messenger software inventory were used. Data were analyzed using descriptive and illative statistics.  Results: The research findings showed that there is a statistically significant relationship between addiction to mobile messenger software's and mental health among the students of physical education (P

Gravitational waves as a new probe of Bose–Einstein condensate Dark Matter

Directory of Open Access Journals (Sweden)

P.S. Bhupal Dev

2017-10-01

Full Text Available There exists a class of ultralight Dark Matter (DM models which could give rise to a Bose–Einstein condensate (BEC in the early universe and behave as a single coherent wave instead of individual particles in galaxies. We show that a generic BEC-DM halo intervening along the line of sight of a gravitational wave (GW signal could induce an observable change in the speed of GWs, with the effective refractive index depending only on the mass and self-interaction of the constituent DM particles and the GW frequency. Hence, we propose to use the deviation in the speed of GWs as a new probe of the BEC-DM parameter space. With a multi-messenger approach to GW astronomy and/or with extended sensitivity to lower GW frequencies, the entire BEC-DM parameter space can be effectively probed by our new method in the near future.

Radiation sensitivity of messenger RNA

International Nuclear Information System (INIS)

Ponta, H.; Pfennig-Yeh, M.L.; Herrlich, P.; Karlsruhe Univ.; Wagner, E.F.; Schweiger, M.

1979-01-01

Messenger RNA function is inactivated by irradiation with ultraviolet light. A unit length mRNA (in bases) is 2-3 times more sensitive than a unit length of DNA (in base pairs) with respect to the inactivation of template function. These data stem from four experimental systems all of which do not repair DNA: the translation of E. coli mRNA in rifampicin-treated cells, of T7 mRNA in infected E.coli, of f2 phage RNA in vivo, and of stable mRNA in chromosomeless minicells. The comparison of relative sensitivities to UV is relevant to the technique of UV mapping of transcription units which enjoys increasing popularity in pro- and eukaryotic genetic research. (orig.) [de

Radiation sensitivity of messenger RNA

Energy Technology Data Exchange (ETDEWEB)

Ponta, H; Pfennig-Yeh, M L; Herrlich, P [Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Inst. fuer Genetik und Toxikologie von Spaltstoffen; Karlsruhe Univ. (TH) (Germany, F.R.). Inst. fuer Genetik); Wagner, E F; Schweiger, M [Innsbruck Univ. (Austria). Inst. fuer Biochemie

1979-08-01

Messenger RNA function is inactivated by irradiation with ultraviolet light. A unit length mRNA (in bases) is 2-3 times more sensitive than a unit length of DNA (in base pairs) with respect to the inactivation of template function. These data stem from four experimental systems all of which do not repair DNA: the translation of E. coli mRNA in rifampicin-treated cells, of T7 mRNA in infected E.coli, of f2 phage RNA in vivo, and of stable mRNA in chromosomeless minicells. The comparison of relative sensitivities to UV is relevant to the technique of UV mapping of transcription units which enjoys increasing popularity in pro- and eukaryotic genetic research.

Modeling MESSENGER Observations of Calcium in Mercury's Exosphere

Science.gov (United States)

Burger, Matthew Howard; Killen, Rosemary M.; McClintock, William E.; Vervack, Ronald J., Jr.; Merkel, Aimee W.; Sprague, Ann L.; Sarantos, Menelaos

2012-01-01

The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MESSENGER spacecraft has made the first high-spatial-resolution observations of exospheric calcium at Mercury. We use a Monte Carlo model of the exosphere to track the trajectories of calcium atoms ejected from the surface until they are photoionized, escape from the system, or stick to the surface. This model permits an exploration of exospheric source processes and interactions among neutral atoms, solar radiation, and the planetary surface. The MASCS data have suggested that a persistent, high-energy source of calcium that was enhanced in the dawn, equatorial region of Mercury was active during MESSENGER's three flybys of Mercury and during the first seven orbits for which MASCS obtained data. The total Ca source rate from the surface varied between 1.2x10(exp 23) and 2.6x10(exp 23) Ca atoms/s, if its temperature was 50,000 K. The origin of this high-energy, asymmetric source is unknown, although from this limited data set it does not appear to be consistent with micrometeoroid impact vaporization, ion sputtering, electron-stimulated desorption, or vaporization at dawn of material trapped on the cold nightside.

DECLINE AND RECOVERY OF THE INTERPLANETARY MAGNETIC FIELD DURING THE PROTRACTED SOLAR MINIMUM

International Nuclear Information System (INIS)

Smith, Charles W.; Schwadron, Nathan A.; DeForest, Craig E.

2013-01-01

The interplanetary magnetic field (IMF) is determined by the amount of solar magnetic flux that passes through the top of the solar corona into the heliosphere, and by the dynamical evolution of that flux. Recently, it has been argued that the total flux of the IMF evolves over the solar cycle due to a combination of flux that extends well outside of 1 AU and is associated with the solar wind, and additionally, transient flux associated with coronal mass ejections (CMEs). In addition to the CME eruption rate, there are three fundamental processes involving conversion of magnetic flux (from transient to wind-associated), disconnection, and interchange reconnection that control the levels of each form of magnetic flux in the interplanetary medium. This is distinct from some earlier models in which the wind-associated component remains steady across the solar cycle. We apply the model of Schwadron et al. that quantifies the sources, interchange, and losses of magnetic flux to 50 yr of interplanetary data as represented by the Omni2 data set using the sunspot number as a proxy for the CME eruption rate. We do justify the use of that proxy substitution. We find very good agreement between the predicted and observed interplanetary magnetic flux. In the absence of sufficient CME eruptions, the IMF falls on the timescale of ∼6 yr. A key result is that rising toroidal flux resulting from CME eruption predates the increase in wind-associated IMF

Observations of the interplanetary sector structure up to heliographic latitudes of 160: Pioneer 11

International Nuclear Information System (INIS)

Smith, E.J.; Tsurutani, B.T.; Rosenberg, R.L.

1978-01-01

A study of the interplanetary sector structure at heliographic latitudes up to 16 0 N is reported. The study is based on magnetic field measurements made on board Pioneer 11 as the spacecraft traveled along the post-Jupiter-encounter trajectory. Preliminary measurements are used to determine the dominant polarity of the interplanetary magnetic field during 43 successive solar rotations including Pioneer's ascent to its maximum latitude and motion inward from 5 to 3.7 AU. As the latitude of Pioneer increased, the dominant polarity became continually more positive, corresponding to an outward-directed solar interplanetary field. When the spacecraft reached the highest latitude, the usual sector structure had essentially disappeared. A histogram of the field longitude angle, based on data acquired during 1 month at 16 0 latitude, shows an almost total absence of inward-directed fields. A comparison with interplanetary field polarities in the ecliptic, as inferred from geomagnetic field variations, rules out the possibility that a time variation rather than a latitude dependence is responsible. The Pioneer 11 observations imply that the boundary between adjacent sectors corresponds physically to a current sheet surrounding the sun and lying near parallel to the solar equatorial plane. Above this current sheet, in the northern hemisphere, the field polarity at this phase of the solar cycle is outward, and below the current sheet, in the southern hemisphere, it is inward. The Pioneer observations confirm earlier theoretical suggestions regarding the existence and equatorial orientation of this current sheet. The properties of the current sheet and some major implications and questions associated with it are discussed. It is shown that the radial component of the sheet current is compensated by the distributed currents in the northern and southern hemispheres associated with the spiraled interplanetary field

The use of x-ray pulsar-based navigation method for interplanetary flight

Science.gov (United States)

Yang, Bo; Guo, Xingcan; Yang, Yong

2009-07-01

As interplanetary missions are increasingly complex, the existing unique mature interplanetary navigation method mainly based on radiometric tracking techniques of Deep Space Network can not meet the rising demands of autonomous real-time navigation. This paper studied the applications for interplanetary flights of a new navigation technology under rapid development-the X-ray pulsar-based navigation for spacecraft (XPNAV), and valued its performance with a computer simulation. The XPNAV is an excellent autonomous real-time navigation method, and can provide comprehensive navigation information, including position, velocity, attitude, attitude rate and time. In the paper the fundamental principles and time transformation of the XPNAV were analyzed, and then the Delta-correction XPNAV blending the vehicles' trajectory dynamics with the pulse time-of-arrival differences at nominal and estimated spacecraft locations within an Unscented Kalman Filter (UKF) was discussed with a background mission of Mars Pathfinder during the heliocentric transferring orbit. The XPNAV has an intractable problem of integer pulse phase cycle ambiguities similar to the GPS carrier phase navigation. This article innovatively proposed the non-ambiguity assumption approach based on an analysis of the search space array method to resolve pulse phase cycle ambiguities between the nominal position and estimated position of the spacecraft. The simulation results show that the search space array method are computationally intensive and require long processing time when the position errors are large, and the non-ambiguity assumption method can solve ambiguity problem quickly and reliably. It is deemed that autonomous real-time integrated navigation system of the XPNAV blending with DSN, celestial navigation, inertial navigation and so on will be the development direction of interplanetary flight navigation system in the future.

Jovian electron bursts: Correlation with the interplanetary field direction and hydromagnetic waves

International Nuclear Information System (INIS)

Smith, E.J.; Tsurutani, B.T.; Chenette, D.L.; Conlon, T.F.; Simpson, J.A.

1976-01-01

The bursts of relativistic electrons detected on Pioneer 10 upstream from Jupiter and within 400r/subj/ of the planet have been found to be correlated with the interplanetary magnetic field. In the three examples upon which this study is based, during the month prior to the Pioneer 10 encounter, electrons with energies between 3 and 6 MeV escaping from Jupiter's magnetosphere were observed only when the interplanetary magnetic field was along the Jupiter-spacecraft line. In addition, large-amplitude interplanetary waves with characteristic periods of 10 min were observed and found to be well correlated with intervals during which the field was along the Jupiter-spacecraft line. Abrupt changes in the field away from the preferred direction caused equally abrupt terminations of the waves with an accompanying reduction in the electron flux. These results are consistent with propagation of the electrons from Jupiter to Pioneer along, rather than across, the magnetic field lines. The direction of the interplanetary magnetic field is apparently not affected by the electron bursts or by other particles from Jupiter. The average Parker spiral direction is clear with no enhancement in the Jupiter-spacecraft direction. Two alternative possibilities are considered for the origin of the waves. If they were generated near Jupiter, they would have to propagate to the spacecraft in the whistler mode. The expected attenuation of these waves over distances of several hundred r/subj/ an their long travel times make this explanation unattractive. Alternatively, hydromagnetic wave generation by Jovian charged particles, presumably the relativistic electrons themselves, as they travel upstream, appears to be an attractive explanation

August 1972 solar-terrestrial events: interplanetary magnetic field observations

Energy Technology Data Exchange (ETDEWEB)

Smith, E J [Jet Propulsion Lab., Pasadena, Calif. (USA)

1976-10-01

A review is presented of the interplanetary magnetic field observations acquired in early August 1972 when four solar flares erupted in McMath Plage region 1976. Measurements of the interplanetary field were obtained by Earth satellites, HEOS-2 and Explorer 41, and by Pioneers 9 and 10 which, by good fortune, were radially aligned and only 45/sup 0/ east of the Earth-Sun direction. In response to the four flares, four interplanetary shocks were seen at Earth and at Pioneer 9, which was then at a heliocentric distance of 0.78 AU. However, at Pioneer 10, which was 2.2 AU from the Sun, only two forward shocks and one reverse shock were seen. The available magnetic field data acquired in the vicinity of the shocks are presented. Efforts to identify corresponding shocks at the several locations and to deduce their velocities of propagation between 0.8 and 2.2 AU are reviewed. The early studies were based on average velocities between the Sun and Pioneer 9, the Sun and Earth and the Sun and Pioneer 10. A large deceleration of the shocks between the Sun and 0.8 AU as well as between 0.8 and 2.2 AU was inferred. More recently the local velocities of the shocks at Pioneers 9 and 10 have become available. A comparision of these velocities shows little, if any, deceleration between 0.8 and 2.2 AU and implies that most or all of the deceleration actually occurred nearer the Sun. Evidence is also presented that shows a significant departure of the flare-generated shock fronts from spherical symmetry.

Solar events and their influence on the interplanetary medium

Science.gov (United States)

Joselyn, Jo Ann

The Workshop on Solar Events and Their Influence on the Interplanetary Medium very successfully met its goal “to foster interactions among colleagues, leading to an improved understanding of the unified relationship between solar events and interplanetary disturbances.” Organized by the National Oceanic and Atmospheric Administration Space Environment Laboratory and funded by the national Aeronautics and Space Administration (NASA) Solar Maximum Mission Principal Investigators and the Space Environment Laboratory, this meeting was held held September 8—11, 1986, in Estes Park, Colo. A total of 94 scientists, including representatives from Argentina, Germany, Japan, France, Scotland, England, Australia, Poland, Israel, Greece, China and the United States attended. A novel meeting schedule was adopted, with no formal presentations other than a keynote address by Rainer Schwenn of the Max Planck Institut fur Aeronomie (Federal republic of Germany), entitled “Transients on the Sun and Their Effects on the Interplanetary Medium: An Interdisciplinary Challenge” a Gordon A. Newkirk Memorial talk on “Early History of the Coronagraph” by John Eddy of the University Corporation for Atmospheric Research Office of Interdisciplinary Earth Studies (Boulder, Colo.); and introductory and summary statements by working group leaders. Instead, there were three working groups, which met either independently or with one of the other groups according to a prearranged plan. Suggested roundtable discussion topics were distributed in advance to the members of each group, but primarily, each group was expected to think of questions for the other groups and respond to requests for information from them. As may be expected, for some topics there was group consensus. Other topics were contentious.

Generalized messenger sector for gauge mediation of supersymmetry breaking and the soft spectrum

International Nuclear Information System (INIS)

Marques, Diego

2009-01-01

We consider a generic renormalizable and gauge invariant messenger sector and derive the sparticle mass spectrum using the formalism introduced for General Gauge Mediation. Our results recover many expressions found in the literature in various limits. Constraining the messenger sector with a global symmetry under which the spurion field is charged, we analyze Extraordinary Gauge Mediation beyond the small SUSY breaking limit. Finally, we include D-term contributions and compute their corrections to the soft masses. This leads to a perturbative framework allowing to explore models capable of fully covering the parameter space of General Gauge Mediation to the Supersymmetric Standard Model.

Mapping the Topography of Mercury with MESSENGER Laser Altimetry

Science.gov (United States)

Sun, Xiaoli; Cavanaugh, John F.; Neumann, Gregory A.; Smith, David E..; Zubor, Maria T.

2012-01-01

The Mercury Laser Altimeter onboard MESSENGER involves unique design elements that deal with the challenges of being in orbit around Mercury. The Mercury Laser Altimeter (MLA) is one of seven instruments on NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. MESSENGER was launched on 3 August 2004, and entered into orbit about Mercury on 18 March 2011 after a journey through the inner solar system. This involved six planetary flybys, including three of Mercury. MLA is designed to map the topography and landforms of Mercury's surface. It also measures the planet's forced libration (motion about the spin axis), which helps constrain the state of the core. The first science measurements from orbit taken with MLA were made on 29 March 2011 and continue to date. MLA had accumulated about 8.3 million laser ranging measurements to Mercury's surface, as of 31 July 2012, i.e., over six Mercury years (528 Earth days). Although MLA is the third planetary lidar built at the NASA Goddard Space Flight Center (GSFC), MLA must endure a much harsher thermal environment near Mercury than the previous instruments on Mars and Earth satellites. The design of MLA was derived in part from that of the Mars Orbiter Laser Altimeter on Mars Global Surveyor. However, MLA must range over greater distances and often in off-nadir directions from a highly eccentric orbit. In MLA we use a single-mode diode-pumped Nd:YAG (neodymium-doped yttrium aluminum garnet) laser that is highly collimated to maintain a small footprint on the planet. The receiver has both a narrow field of view and a narrow spectral bandwidth to minimize the amount of background light detected from the sunlit hemisphere of Mercury. We achieve the highest possible receiver sensitivity by employing the minimum receiver detection threshold.

The near-Earth and interplanetary plasma

International Nuclear Information System (INIS)

Al'pert, Y.L.

1983-01-01

This monograph is an extensive revision and expansion of the original paper which first appeared in 1976 in the encyclopedia, Handbuch der Physik. It presents a detailed and comprehensive treatment of wave processes and of the motion of bodies through plasma around moving bodies such as artificial satellites, and with natural plasma waves and oscillations. Contents, abridged: General properties of the near-Earth and interplanetary plasma. Refractive indexes of cold magnetoplasma. Growth rates for the different oscillation branches. Nonlinear effects in a plasma. Group velocity, trajectories, and trapping of electromagnetic waves in a magnetoplasma. Indexes

Evidence for young volcanism on Mercury from the third MESSENGER flyby.

Science.gov (United States)

Prockter, Louise M; Ernst, Carolyn M; Denevi, Brett W; Chapman, Clark R; Head, James W; Fassett, Caleb I; Merline, William J; Solomon, Sean C; Watters, Thomas R; Strom, Robert G; Cremonese, Gabriele; Marchi, Simone; Massironi, Matteo

2010-08-06

During its first two flybys of Mercury, the MESSENGER spacecraft acquired images confirming that pervasive volcanism occurred early in the planet's history. MESSENGER's third Mercury flyby revealed a 290-kilometer-diameter peak-ring impact basin, among the youngest basins yet seen, having an inner floor filled with spectrally distinct smooth plains. These plains are sparsely cratered, postdate the formation of the basin, apparently formed from material that once flowed across the surface, and are therefore interpreted to be volcanic in origin. An irregular depression surrounded by a halo of bright deposits northeast of the basin marks a candidate explosive volcanic vent larger than any previously identified on Mercury. Volcanism on the planet thus spanned a considerable duration, perhaps extending well into the second half of solar system history.

MESSENGER Observations of Extreme Loading and Unloading of Mercury's Magnetic Tail

Science.gov (United States)

Slavin, James A.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Boardsen, Scott A.; Gloeckler, George; Gold, Robert E.; Ho, George C.; Korth, Haje; Krimigis, Stamatios M.;

MESSENGER observations of Mercury's exosphere: detection of magnesium and distribution of constituents.

Science.gov (United States)

McClintock, William E; Vervack, Ronald J; Bradley, E Todd; Killen, Rosemary M; Mouawad, Nelly; Sprague, Ann L; Burger, Matthew H; Solomon, Sean C; Izenberg, Noam R

2009-05-01

Mercury is surrounded by a tenuous exosphere that is supplied primarily by the planet's surface materials and is known to contain sodium, potassium, and calcium. Observations by the Mercury Atmospheric and Surface Composition Spectrometer during MESSENGER's second Mercury flyby revealed the presence of neutral magnesium in the tail (anti-sunward) region of the exosphere, as well as differing spatial distributions of magnesium, calcium, and sodium atoms in both the tail and the nightside, near-planet exosphere. Analysis of these observations, supplemented by observations during the first Mercury flyby, as well as those by other MESSENGER instruments, suggests that the distinct spatial distributions arise from a combination of differences in source, transfer, and loss processes.

Solar cycle variation of cosmic ray intensity along with interplanetary and solar wind plasma parameters

International Nuclear Information System (INIS)

Mishra, R.K.; Tiwari, S.; Agarwal, R.

2008-01-01

Galactic cosmic rays are modulated at their propagation in the heliosphere by the effect of the large-scale structure of the interplanetary medium. A comparison of the variations in the cosmic ray intensity data obtained by neutron monitoring stations with those in geomagnetic disturbance, solar wind velocity (V), interplanetary magnetic field (B), and their product (V , B) near the Earth for the period 1964-2004 has been presented so as to establish a possible correlation between them. We used the hourly averaged cosmic ray counts observed with the neutron monitor in Moscow. It is noteworthy that a significant negative correlation has been observed between the interplanetary magnetic field, product (V , B) and cosmic ray intensity during the solar cycles 21 and 22. The solar wind velocity has a good positive correlation with cosmic ray intensity during solar cycle 21, whereas it shows a weak correlation during cycles 20, 22 and 23. The interplanetary magnetic field shows a weak negative correlation with cosmic rays for solar cycle 20, and a good anti-correlation for solar cycles 21-23 with the cosmic ray intensity, which, in turn, shows a good positive correlation with disturbance time index (Dst) during solar cycles 21 and 22, and a weak correlation for cycles 20 and 23. (Authors)

Outer Radiation Belt Dropout Dynamics Following the Arrival of Two Interplanetary Coronal Mass Ejections

Science.gov (United States)

Alves, L. R.; Da Silva, L. A.; Souza, V. M.; Sibeck, D. G.; Jauer, P. R.; Vieira, L. E. A.; Walsh, B. M.; Silveira, M. V. D.; Marchezi, J. P.; Rockenbach, M.;

MESSENGER E/V/H GRNS 3 NEUTRON SPECTROMETER CDR V1.0

Data.gov (United States)

National Aeronautics and Space Administration — Abstract ======== This data set consists of the MESSENGER Neutron Spectrometer (NS) calibrated data records (CDRs). The NS experiment is a neutron spectrometer...

MESSENGER E/V/H/SW EPPS CALIBRATED FIPS DDR V2.0

Data.gov (United States)

National Aeronautics and Space Administration — Abstract ======== This data set consists of the MESSENGER Energetic Particle and Plasma Spectrometer (EPPS) calibrated observations, also known as DDRs. The system...

Neuronal chemokines : Versatile messengers in central nervous system cell interaction

NARCIS (Netherlands)

de Haas, A. H.; van Weering, H. R. J.; de Jong, E. K.; Boddeke, H. W. G. M.; Biber, K. P. H.

2007-01-01

Whereas chemokines are well known for their ability to induce cell migration, only recently it became evident that chemokines also control a variety of other cell functions and are versatile messengers in the interaction between a diversity of cell types. In the central nervous system (CNS),

A new propulsion concept for interplanetary missions

Science.gov (United States)

Dujarric, C.

2001-11-01

When tons of payload must be brought back from the planets to Earth, the current launch-system technology hits size limitations. The huge Saturn-V launcher that enabled the Apollo missions to go to the Moon would be dwarfed by a single launcher capable of sending men to a destination like Mars and bringing them back. Keeping interplanetary missions within a reasonable size and cost therefore requires technological progress in terms of both vehicle weight reduction and propulsion efficiency.

Detection of chromogranins A and B in endocrine tissues with radioactive and biotinylated oligonucleotide probes

International Nuclear Information System (INIS)

Lloyd, R.V.; Jin, L.; Fields, K.

1990-01-01

We analyzed the distribution of chromogranins A and B in normal and neoplastic endocrine tissues with secretory granules using 35 S-labeled and biotin-labeled oligonucleotide probes by in situ hybridization (ISH). Both radioactive and nonradioactive probes detected messenger RNAs (mRNAs) in frozen and paraffin tissue sections. Endocrine tissues with variable immunoreactivities for chromogranin A protein, such as small-cell lung carcinomas, neuroblastomas, insulinomas, and parathyroid adenomas, expressed the mRNA for chromogranins A and B in most cells. Some technical problems with the biotinylated probes included nonspecific nuclear staining and endogenous alkaline phosphatase, which was not completely abolished by levamisole pretreatment. A differential distribution of chromogranins A and B was seen in pituitary prolactinomas, which expressed abundant chromogranin B but not chromogranin A mRNAs, and in parathyroid adenomas, which expressed abundant chromogranin A but only small amounts of chromogranin B mRNAs. These results indicate that ISH can be used to detect chromogranins A and B in endocrine tissues with radioactive and biotinylated oligonucleotide probes and that the mRNAs for chromogranin A and B are demonstrable in some tumors even when the chromogranin proteins cannot be detected by immunohistochemistry

Detection of chromogranins A and B in endocrine tissues with radioactive and biotinylated oligonucleotide probes

Energy Technology Data Exchange (ETDEWEB)

Lloyd, R.V.; Jin, L.; Fields, K. (Univ. of Michigan, Ann Arbor (USA))

1990-01-01

We analyzed the distribution of chromogranins A and B in normal and neoplastic endocrine tissues with secretory granules using {sup 35}S-labeled and biotin-labeled oligonucleotide probes by in situ hybridization (ISH). Both radioactive and nonradioactive probes detected messenger RNAs (mRNAs) in frozen and paraffin tissue sections. Endocrine tissues with variable immunoreactivities for chromogranin A protein, such as small-cell lung carcinomas, neuroblastomas, insulinomas, and parathyroid adenomas, expressed the mRNA for chromogranins A and B in most cells. Some technical problems with the biotinylated probes included nonspecific nuclear staining and endogenous alkaline phosphatase, which was not completely abolished by levamisole pretreatment. A differential distribution of chromogranins A and B was seen in pituitary prolactinomas, which expressed abundant chromogranin B but not chromogranin A mRNAs, and in parathyroid adenomas, which expressed abundant chromogranin A but only small amounts of chromogranin B mRNAs. These results indicate that ISH can be used to detect chromogranins A and B in endocrine tissues with radioactive and biotinylated oligonucleotide probes and that the mRNAs for chromogranin A and B are demonstrable in some tumors even when the chromogranin proteins cannot be detected by immunohistochemistry.

Cultural ethology as a new approach of interplanetary crew's behavior

Science.gov (United States)

Tafforin, Carole; Giner Abati, Francisco

2017-10-01

From an evolutionary perspective, during short-term and medium-term orbital flights, human beings developed new spatial and motor behaviors to compensate for the lack of terrestrial gravity. Past space ethological studies have shown adaptive strategies to the tri-dimensional environment, with the goal of optimizing relationships between the astronaut and unusual sensorial-motor conditions. During a long-term interplanetary journey, crewmembers will have to develop new individual and social behaviors to adapt, far from earth, to isolation and confinement and as a result to extreme conditions of living and working together. Recent space psychological studies pointed out that heterogeneity is a feature of interplanetary crews, based on personality, gender mixing, internationality and diversity of backgrounds. Intercultural issues could arise between space voyagers. As a new approach we propose to emphasize the behavioral strategies of human groups' adaptation to this new multicultural dimension of the environment.

A DATABASE OF >20 keV ELECTRON GREEN'S FUNCTIONS OF INTERPLANETARY TRANSPORT AT 1 AU

Energy Technology Data Exchange (ETDEWEB)

Agueda, N.; Sanahuja, B. [Departament d' Astronomia i Meteorologia, Institut de Ciencies del Cosmos, Universitat de Barcelona, Barcelona (Spain); Vainio, R. [Department of Physics, University of Helsinki, Helsinki (Finland)

2012-10-15

We use interplanetary transport simulations to compute a database of electron Green's functions, i.e., differential intensities resulting at the spacecraft position from an impulsive injection of energetic (>20 keV) electrons close to the Sun, for a large number of values of two standard interplanetary transport parameters: the scattering mean free path and the solar wind speed. The nominal energy channels of the ACE, STEREO, and Wind spacecraft have been used in the interplanetary transport simulations to conceive a unique tool for the study of near-relativistic electron events observed at 1 AU. In this paper, we quantify the characteristic times of the Green's functions (onset and peak time, rise and decay phase duration) as a function of the interplanetary transport conditions. We use the database to calculate the FWHM of the pitch-angle distributions at different times of the event and under different scattering conditions. This allows us to provide a first quantitative result that can be compared with observations, and to assess the validity of the frequently used term beam-like pitch-angle distribution.

Ultra-sensitive DNA assay based on single-molecule detection coupled with fluorescent quantum dot-labeling and its application to determination of messenger RNA

International Nuclear Information System (INIS)

Li Li; Li Xincang; Li Lu; Wang Jinxing; Jin Wenrui

2011-01-01

An ultra-sensitive single-molecule detection (SMD) method for quantification of DNA using total internal reflection fluorescence microscopy (TIRFM) coupled with fluorescent quantum dot (QD)-labeling was developed. In this method, the target DNA (tDNA) was captured by the capture DNA immobilized on the silanized coverslip blocked with ethanolamine and bovine serum albumin. Then, the QD-labeled probe DNA was hybridized to the tDNA. Ten fluorescent images of the QD-labeled sandwich DNA hybrids on the coverslip were taken by a high-sensitive CCD. The tDNA was quantified by counting the bright spots on the images using a calibration curve. The LOD of the method was 1 x 10 -14 mol L -1 . Several key factors, including image acquirement, fluorescence probe, substrate preparation, noise elimination from solutions and glass coverslips, and nonspecific adsorption and binding of solution-phase detection probes were discussed in detail. The method could be applied to quantify messenger RNA (mRNA) in cells. In order to determine mRNA, double-stranded RNA-DNA hybrids consisting of mRNA and corresponding cDNA were synthesized from the cellular mRNA template using reverse transcription in the presence of reverse transcriptase. After removing the mRNA in the double-stranded hybrids using ribonuclease, cDNA was quantified using the SMD-based TIRFM. Osteopontin mRNA in decidual stromal cells was chosen as the model analyte.

Primary structure of the. cap alpha. -subunit of Na/sup +/, K/sup +/-ATPase. II. Isolation, reverse transcription, and cloning of messenger RNA

Energy Technology Data Exchange (ETDEWEB)

Petrukhin, K.E.; Broude, N.E.; Arsenyan, S.G.; Grishin, A.V.; Dzhandzhugazyan, K.N.; Modyanov, N.N.

1986-10-01

The messenger RNA coding the ..cap alpha..-subunit of Na/sup +/,K/sup +/-ATPase has been isolated from the outer medullary layer of porcine kidneys. The mRNA gives a specific hybridization band in the 25S-26S region with three oligonucleotide probes synthesized on the basis of information on the structure of three peptides isolated from a tryptic hydrolyzate of the ..cap alpha..-subunit of Na/sup +/,K/sup +/-ATPase. The translation of the mRNA in Xenopus laevis oocytes followed by immunochemical identification of the products of synthesis confirmed the presence of the mRNA of the ..cap alpha..-subunit of Na/sup +/,K/sup +/-ATPase in an enriched fraction of poly(A/sup +/)-RNA. This preparation has been used for the synthesis of cloning of double-stranded cDNA.

Tracking a major interplanetary disturbance

International Nuclear Information System (INIS)

Tappin, S.J.; Hewish, A.; Gapper, G.R.

1983-01-01

The severe geomagnetic storm which occurred during 27-29 August 1978 was remarkable because it arrived unexpectedly and was not related to a solar flare or long-lived coronal hole. Observations on 900 celestial radio sources show that the storm was associated with a large-scale region causing enhanced interplanetary scintillation which enveloped the Earth at the same time. The disturbance was first detected on 26 August, when the outer boundary had reached a distance of about 0.8 a.u. from the Sun and it was tracked until 30 August. The enhancement was followed by a fast solar wind stream and its shape suggests that it was a compression zone caused by the birth of the stream. (author)

MESSENGER H XRS 5 REDUCED DATA RECORD (RDR) FOOTPRINTS V1.0

Data.gov (United States)

National Aeronautics and Space Administration — Abstract ======== This data set consists of the MESSENGER XRS reduced data record (RDR) footprints which are derived from the navigational meta-data for each...

Remarks on transport theories of interplanetary fluctuations

International Nuclear Information System (INIS)

Ye Zhou; Matthaeus, W.H.

1990-01-01

The structure of approximate transport theories for the radial behavior of interplanetary fluctuations is reconsidered. The emphasis is on theories derived under the assumption of scale separation; i.e., the correlation length of the fluctuations is much less than the scale of large inhomogeneities. In these cases the zero-wavelength limit provides a first approximation to the spectral evolution equations for the radial dependence of interplanetary fluctuation spectra. The goal here is to investigate the structure of a recently presented (Zhou and Matthaeus, 1989) transport theory, in which coupling of inward- and outward-type fluctuations appears in the leading order, an effect the authors call mixing. In linear theory, mixing-type couplings of inward-type and outward-type waves are formally a nonresonant effect. However, leading order mixing terms do not vanish at zero wavelength for fluctuations that vary nearly perpendicular to the local magnetic field, or when the mean magnetic field is weak. Leading order mixing terms also survive when the dispersion relation fails and there is a nonunique relationship between frequency and wave number. The former case corresponds to nearly two-dimensional structures; these are included, for example, in isotropic models of turbulence. The latter instance occurs when wave-wave couplings are sufficiently strong. Thus there are a variety of situations in which leading order mixing effects are expected to be present

Radiative natural SUSY spectrum from deflected AMSB scenario with messenger-matter interactions

Energy Technology Data Exchange (ETDEWEB)

Wang, Fei [School of Physics, Zhengzhou University,Zhengzhou 450000 (China); State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics, Chinese Academy of Sciences,Beijing 100080 (China); Yang, Jin Min [State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics, Chinese Academy of Sciences,Beijing 100080 (China); Department of Physics, Tohoku University,Sendai 980-8578 (Japan); Zhang, Yang [State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics, Chinese Academy of Sciences,Beijing 100080 (China)

2016-04-29

A radiative natural SUSY spectrum are proposed in the deflected anomaly mediation scenario with general messenger-matter interactions. Due to the contributions from the new interactions, positive slepton masses as well as a large |A{sub t}| term can naturally be obtained with either sign of deflection parameter and few messenger species (thus avoid the possible Landau pole problem). In this scenario, in contrast to the ordinary (radiative) natural SUSY scenario with under-abundance of dark matter (DM), the DM can be the mixed bino-higgsino and have the right relic density. The 125 GeV Higgs mass can also be easily obtained in our scenario. The majority of low EW fine tuning points can be covered by the XENON-1T direct detection experiments.

3',5'-cIMP as Potential Second Messenger in the Vascular Wall.

Science.gov (United States)

Leung, Susan W S; Gao, Yuansheng; Vanhoutte, Paul M

2017-01-01

Traditionally, only the 3',5'-cyclic monophosphates of adenosine and guanosine (produced by adenylyl cyclase and guanylyl cyclase, respectively) are regarded as true "second messengers" in the vascular wall, despite the presence of other cyclic nucleotides in different tissues. Among these noncanonical cyclic nucleotides, inosine 3',5'-cyclic monophosphate (cIMP) is synthesized by soluble guanylyl cyclase in porcine coronary arteries in response to hypoxia, when the enzyme is activated by endothelium-derived nitric oxide. Its production is associated with augmentation of vascular contraction mediated by stimulation of Rho kinase. Based on these findings, cIMP appears to meet most, if not all, of the criteria required for it to be accepted as a "second messenger," at least in the vascular wall.

Prospective Out-of-ecliptic White-light Imaging of Interplanetary Corotating Interaction Regions at Solar Maximum

Energy Technology Data Exchange (ETDEWEB)

Xiong, Ming; Yang, Liping; Liu, Ying D.; Keiji, Hayashi; Li, Huichao [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing (China); Davies, Jackie A.; Harrison, Richard A. [RAL Space, STFC-Rutherford Appleton Laboratory, Harwell Campus, Didcot (United Kingdom); Li, Bo; Xia, Lidong, E-mail: mxiong@spacweather.ac.cn [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai (China)

2017-07-20

Interplanetary corotating interaction regions (CIRs) can be remotely imaged in white light (WL), as demonstrated by the Solar Mass Ejection Imager (SMEI) on board the Coriolis spacecraft and Heliospheric Imagers (HIs) on board the twin Solar TErrestrial RElations Observatory ( STEREO ) spacecraft. The interplanetary WL intensity, due to Thomson scattering of incident sunlight by free electrons, is jointly determined by the 3D distribution of electron number density and line-of-sight (LOS) weighting factors of the Thomson-scattering geometry. The 2D radiance patterns of CIRs in WL sky maps look very different from different 3D viewpoints. Because of the in-ecliptic locations of both the STEREO and Coriolis spacecraft, the longitudinal dimension of interplanetary CIRs has, up to now, always been integrated in WL imagery. To synthesize the WL radiance patterns of CIRs from an out-of-ecliptic (OOE) vantage point, we perform forward magnetohydrodynamic modeling of the 3D inner heliosphere during Carrington Rotation CR1967 at solar maximum. The mixing effects associated with viewing 3D CIRs are significantly minimized from an OOE viewpoint. Our forward modeling results demonstrate that OOE WL imaging from a latitude greater than 60° can (1) enable the garden-hose spiral morphology of CIRs to be readily resolved, (2) enable multiple coexisting CIRs to be differentiated, and (3) enable the continuous tracing of any interplanetary CIR back toward its coronal source. In particular, an OOE view in WL can reveal where nascent CIRs are formed in the extended corona and how these CIRs develop in interplanetary space. Therefore, a panoramic view from a suite of wide-field WL imagers in a solar polar orbit would be invaluable in unambiguously resolving the large-scale longitudinal structure of CIRs in the 3D inner heliosphere.

Interplanetary magnetic field orientations associated with bidirectional electron heat fluxes detected at ISEE 3

International Nuclear Information System (INIS)

Stansberry, J.A.; Gosling, J.T.; Thomsen, M.F.; Bame, S.J.; Smith, E.J.

1988-01-01

A statistical survey of interplanetary magnetic field orientations associated with bidirectional electron heat fluxes observed at ISEE 3 in orbit about the Sunward Lagrange point indicates that magnetic connection of the spacecraft to the Earth's bow shock was frequently the source of the bidirectionality. When the interplanetary magnetic field was oriented within 5 0 of the Earth-spacecraft line, backstreaming electrons from the bow shock were clearly observed approximately 18% of the time, and connections apparently occurred for angles as large as ∼30 0 --35 0 . copyright American Geophysical Union 1988

Observations of interplanetary dust by the Juno magnetometer investigation

DEFF Research Database (Denmark)

Benn, Mathias; Jørgensen, John Leif; Denver, Troelz

2017-01-01

One of the Juno magnetometer investigation's star cameras was configured to search for unidentified objects during Juno's transit en route to Jupiter. This camera detects and registers luminous objects to magnitude 8. Objects persisting in more than five consecutive images and moving with an appa...... on the distribution and motion of interplanetary (>μm sized) dust....

The thickness of the interplanetary collisionless shock waves

International Nuclear Information System (INIS)

Pinter, S.

1980-05-01

The thicknesses of magnetic structures of the interplanetary shock waves related to the upstream solar wind plasma parameters are studied. From this study the following results have been obtained: the measured shock thickness increases for decreasing upstream proton number density and decreases for increasing proton flux energy. The shock thickness strongly depends on the ion plasma β, i.e. for higher values of the β the thickness decreases. (author)

3rd Interplanetary Network Gamma-Ray Burst Website

Science.gov (United States)

Hurley, Kevin

1998-05-01

We announce the opening of the 3rd Interplanetary Network web site at http://ssl.berkeley.edu/ipn3/index.html This site presently has four parts: 1. A bibliography of over 3000 publications on gamma-ray bursts, 2. IPN data on all bursts triangulated up to February 1998, 3. A master list showing which spacecraft observed which bursts, 4. Preliminary IPN data on the latest bursts observed.

CHARGED DUST GRAIN DYNAMICS SUBJECT TO SOLAR WIND, POYNTING–ROBERTSON DRAG, AND THE INTERPLANETARY MAGNETIC FIELD

Energy Technology Data Exchange (ETDEWEB)

Lhotka, Christoph; Bourdin, Philippe; Narita, Yasuhito, E-mail: christoph.lhotka@oeaw.ac.at, E-mail: philippe.bourdin@oeaw.ac.at, E-mail: yasuhito.narita@oeaw.ac.at [Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, A-8042 Graz (Austria)

2016-09-01

We investigate the combined effect of solar wind, Poynting–Robertson drag, and the frozen-in interplanetary magnetic field on the motion of charged dust grains in our solar system. For this reason, we derive a secular theory of motion by the means of an averaging method and validate it with numerical simulations of the unaveraged equations of motions. The theory predicts that the secular motion of charged particles is mainly affected by the z -component of the solar magnetic axis, or the normal component of the interplanetary magnetic field. The normal component of the interplanetary magnetic field leads to an increase or decrease of semimajor axis depending on its functional form and sign of charge of the dust grain. It is generally accepted that the combined effects of solar wind and photon absorption and re-emmision (Poynting–Robertson drag) lead to a decrease in semimajor axis on secular timescales. On the contrary, we demonstrate that the interplanetary magnetic field may counteract these drag forces under certain circumstances. We derive a simple relation between the parameters of the magnetic field, the physical properties of the dust grain, as well as the shape and orientation of the orbital ellipse of the particle, which is a necessary conditions for the stabilization in semimajor axis.

Cosmic neutrinos as a probe of TeV-scale physics

Energy Technology Data Exchange (ETDEWEB)

Ahlers, M.

2007-02-15

Ultra-high energy cosmic neutrinos are versatile probes of astrophysics, astronomy, and particle physics. They represent the messengers of hadronic processes in cosmic accelerators and survive the propagation through the interstellar medium practically unscathed. We investigate the neutrino fluxes associated with optically thin proton sources which provide a diagnostic of the transition between galactic and extragalactic cosmic rays. The center of mass energies in collisions of these cosmic neutrinos with atomic nuclei in the atmosphere or the Earth's interior easily exceed those so far reached in man-made accelerators. We discuss the prospects of observing supersymmetric neutrino interactions with Cherenkov telescopes and speculate about a neutrino component in extremely high energy cosmic rays from exotic interactions in the atmosphere. (orig.)

A Free-Return Earth-Moon Cycler Orbit for an Interplanetary Cruise Ship

Science.gov (United States)

Genova, Anthony L.; Aldrin, Buzz

2015-01-01

A periodic circumlunar orbit is presented that can be used by an interplanetary cruise ship for regular travel between Earth and the Moon. This Earth-Moon cycler orbit was revealed by introducing solar gravity and modest phasing maneuvers (average of 39 m/s per month) which yields close-Earth encounters every 7 or 10 days. Lunar encounters occur every 26 days and offer the chance for a smaller craft to depart the cycler and enter lunar orbit, or head for a Lagrange point (e.g., EM-L2 halo orbit), distant retrograde orbit (DRO), or interplanetary destination such as a near-Earth object (NEO) or Mars. Additionally, return-to-Earth abort options are available from many points along the cycling trajectory.

Counterstreaming electrons in small interplanetary magnetic flux ropes

Science.gov (United States)

Feng, H. Q.; Zhao, G. Q.; Wang, J. M.

2015-12-01

Small interplanetary magnetic flux ropes (SIMFRs) are commonly observed by spacecraft at 1 AU, and their origin still remains disputed. We investigated the counterstreaming suprathermal electron (CSE) signatures of 106 SIMFRs measured by Wind during 1995-2005. We found that 79 (75%) of the 106 flux ropes contain CSEs, and the percentages of counterstreaming vary from 8% to 98%, with a mean value of 51%. CSEs are often observed in magnetic clouds (MCs), and this indicates these MCs are still attached to the Sun at both ends. CSEs are also related to heliospheric current sheets (HCSs) and the Earth's bow shock. We divided the SIMFRs into two categories: The first category is far from HCSs, and the second category is in the vicinity of HCSs. The first category has 57 SIMFRs, and only 7 of 57 ropes have no CSEs. This ratio is similar to that of MCs. The second category has 49 SIMFRs; however, 20 of the 49 events have no CSEs. This ratio is larger than that of MCs. These two categories have different origins. One category originates from the solar corona, and most ropes are still connected to the Sun at both ends. The other category is formed near HCSs in the interplanetary space.

The measurement of interplanetary scintillations in conditions of strong radio interference

International Nuclear Information System (INIS)

Duffett-Smith, P.J.

1980-01-01

Observations of interplanetary scintillations (IPS) are often severely limited by interference from man-made transmissions within the receiver pass-band. A new method of measuring IPS is described which can give useful data even in conditions of bad interference. (author)

Evolution and interaction of large interplanetary streams

International Nuclear Information System (INIS)

Whang, Y.C.; Burlaga, L.F.

1985-02-01

A computer simulation for the evolution and interaction of large interplanetary streams based on multi-spacecraft observations and an unsteady, one-dimensional MHD model is presented. Two events, each observed by two or more spacecraft separated by a distance of the order of 10 AU, were studied. The first simulation is based on the plasma and magnetic field observations made by two radially-aligned spacecraft. The second simulation is based on an event observed first by Helios-1 in May 1980 near 0.6 AU and later by Voyager-1 in June 1980 at 8.1 AU. These examples show that the dynamical evolution of large-scale solar wind structures is dominated by the shock process, including the formation, collision, and merging of shocks. The interaction of shocks with stream structures also causes a drastic decrease in the amplitude of the solar wind speed variation with increasing heliocentric distance, and as a result of interactions there is a large variation of shock-strengths and shock-speeds. The simulation results shed light on the interpretation for the interaction and evolution of large interplanetary streams. Observations were made along a few limited trajectories, but simulation results can supplement these by providing the detailed evolution process for large-scale solar wind structures in the vast region not directly observed. The use of a quantitative nonlinear simulation model including shock merging process is crucial in the interpretation of data obtained in the outer heliosphere

Statistical study of interplanetary condition effect on geomagnetic storms: 2. Variations of parameters

Science.gov (United States)

Yermolaev, Yu. I.; Lodkina, I. G.; Nikolaeva, N. S.; Yermolaev, M. Yu.

2011-02-01

We investigate the behavior of mean values of the solar wind’s and interplanetary magnetic field’s (IMF) parameters and their absolute and relative variations during the magnetic storms generated by various types of the solar wind. In this paper, which is a continuation of paper [1], we, on the basis of the OMNI data archive for the period of 1976-2000, have analyzed 798 geomagnetic storms with D st ≤ -50 nT and their interplanetary sources: corotating interaction regions CIR, compression regions Sheath before the interplanetary CMEs; magnetic clouds MC; “Pistons” Ejecta, and an uncertain type of a source. For the analysis the double superposed epoch analysis method was used, in which the instants of the magnetic storm onset and the minimum of the D st index were taken as reference times. It is shown that the set of interplanetary sources of magnetic storms can be sub-divided into two basic groups according to their slowly and fast varying characteristics: (1) ICME (MC and Ejecta) and (2) CIR and Sheath. The mean values, the absolute and relative variations in MC and Ejecta for all parameters appeared to be either mean or lower than the mean value (the mean values of the electric field E y and of the B z component of IMF are higher in absolute value), while in CIR and Sheath they are higher than the mean value. High values of the relative density variation sN/ are observed in MC. At the same time, the high values for relative variations of the velocity, B z component, and IMF magnitude are observed in Sheath and CIR. No noticeable distinctions in the relationships between considered parameters for moderate and strong magnetic storms were observed.

Mercury's exosphere: observations during MESSENGER's First Mercury flyby.

Science.gov (United States)

McClintock, William E; Bradley, E Todd; Vervack, Ronald J; Killen, Rosemary M; Sprague, Ann L; Izenberg, Noam R; Solomon, Sean C

2008-07-04

During MESSENGER's first Mercury flyby, the Mercury Atmospheric and Surface Composition Spectrometer measured Mercury's exospheric emissions, including those from the antisunward sodium tail, calcium and sodium close to the planet, and hydrogen at high altitudes on the dayside. Spatial variations indicate that multiple source and loss processes generate and maintain the exosphere. Energetic processes connected to the solar wind and magnetospheric interaction with the planet likely played an important role in determining the distributions of exospheric species during the flyby.

Motion of the sources for type II and type IV radio bursts and flare-associated interplanetary disturbances

Science.gov (United States)

Sakurai, K.; Chao, J. K.

1974-01-01

Shock waves are indirectly observed as the source of type II radio bursts, whereas magnetic bottles are identified as the source of moving metric type IV radio bursts. The difference between the expansion speeds of these waves and bottles is examined during their generation and propagation near the flare regions. It is shown that, although generated in the explosive phase of flares, the bottles behave quite differently from the waves and that the bottles are generally much slower than the waves. It has been suggested that the waves are related to flare-associated interplanetary disturbances which produce SSC geomagnetic storms. These disturbances may, therefore, be identified as interplanetary shock waves. The relationship among magnetic bottles, shock waves near the sun, and flare-associated disturbances in interplanetary space is briefly discussed.

Social and Virtual Networks: Evaluating Synchronous Online Interviewing Using Instant Messenger

Science.gov (United States)

Hinchcliffe, Vanessa; Gavin, Helen

2009-01-01

This paper describes an evaluation of the quality and utility of synchronous online interviewing for data collection in social network research. Synchronous online interviews facilitated by Instant Messenger as the communication medium, were undertaken with ten final year university students. Quantitative and qualitative content analysis of…

The interaction of a very large interplanetary magnetic cloud with the magnetosphere and with cosmic rays

International Nuclear Information System (INIS)

Lepping, R.P.; Burlaga, L.F.; Ogilvie, K.W.; Tsurutani, B.T.; Lazarus, A.J.; Evans, D.S.; Klein, L.W.

1991-01-01

A large interplanetary magnetic cloud has been observed in the mid-December 1982 data from ISEE 3. It is estimated to have a heliocentric radial extent of approx-gt 0.4 AU, making it one of the largest magnetic clouds yet observed at 1 AU. The magnetic field measured throughout the main portion of the cloud was fairly tightly confined to a plane as it changed direction by 174 degree while varying only moderately in magnitude. Throughout nearly the entire duration of the cloud's passage, IMP 8 was located in the Earth's dawn magnetosheath providing observations of this cloud's interaction with the bow shock and magnetopause; the cloud is shown to maintain its solar wind characteristics during the interaction. Near the end of the cloud passage, at 0806 UT on December 17, ISEE 3 (and IMP 8 at nearly the same time) observed an oblique fast forward interplanetary shock closely coincident in time with a geomagnetic storm sudden commencement. The shock, moving much faster than the cloud (radial speeds of 700 and 390 km/s, respectively, on the average), was in the process of overtaking the cloud. The index Dst decreased monotonically by ∼ 130 nT during the 2-day cloud passage by the Earth and was well correlated with the B z component of the interplanetary magnetic field. There was no significant decrease in the cosmic ray intensity recorded by ground-based neutron monitors at this time of rather strong, smoothly changing fields. However, a Forbush decrease did occur immediately after the interplanetary shock, during a period of significant field turbulence. Thus a large, smooth, interplanetary helical magnetic field configuration engulfing the Earth does not necessarily deflect cosmic rays sufficiently to cause a Forbush decrease, but there is a suggestion that such a decrease may be caused by particle scattering by turbulent magnetic fields

12th International Conference on Second Messengers and Phosphoproteins

Czech Academy of Sciences Publication Activity Database

Tuháčková, Zdena

2004-01-01

Roč. 32, č. 3 (2004), s. 89-91 ISSN 1211-2526. [International conference on second messengers and phosphoproteins /12./. Montreal, 03.08.2004-07.08.2004] R&D Projects: GA ČR GA301/04/0550; GA AV ČR KSK5020115 Institutional research plan: CEZ:AV0Z5052915 Keywords : MTOR -PI3-K signalling * p70 S 6 kinase * v-Src Subject RIV: CE - Biochemistry

Potential Cislunar and Interplanetary Proving Ground Excursion Trajectory Concepts

Science.gov (United States)

McGuire, Melissa L.; Strange, Nathan J.; Burke, Laura M.; MacDonald, Mark A.; McElrath, Timothy P.; Landau, Damon F.; Lantoine, Gregory; Hack, Kurt J.; Lopez, Pedro

2016-01-01

NASA has been investigating potential translunar excursion concepts to take place in the 2020s that would be used to test and demonstrate long duration life support and other systems needed for eventual Mars missions in the 2030s. These potential trajectory concepts could be conducted in the proving ground, a region of cislunar and near-Earth interplanetary space where international space agencies could cooperate to develop the technologies needed for interplanetary spaceflight. Enabled by high power Solar Electric Propulsion (SEP) technologies, the excursion trajectory concepts studied are grouped into three classes of increasing distance from the Earth and increasing technical difficulty: the first class of excursion trajectory concepts would represent a 90-120 day round trip trajectory with abort to Earth options throughout the entire length, the second class would be a 180-210 day round trip trajectory with periods in which aborts would not be available, and the third would be a 300-400 day round trip trajectory without aborts for most of the length of the trip. This paper provides a top-level summary of the trajectory and mission design of representative example missions of these three classes of excursion trajectory concepts.

MESSENGER E/V/H MLA 3/4 CDR/RDR DATA V1.0

Data.gov (United States)

National Aeronautics and Space Administration — Abstract ======== This data set consists of the MESSENGER Mercury Laser Altimeter (MLA) Calibrated Data Record (CDR) and Reduced Data Record (RDR) products. The MLA...

A Telescopic and Microscopic Examination of Acceleration in the June 2015 Geomagnetic Storm: Magnetospheric Multiscale and Van Allen Probes Study of Substorm Particle Injection

Science.gov (United States)

Baker, D. N.; Jaynes, A. N.; Turner, D. L.; Nakamura, R.; Schmid, D.; Mauk, B. H.; Cohen, I. J.; Fennell, J. F.; Blake, J. B.; Strangeway, R. J.;

Astronomy's New Messengers: A traveling exhibit to out to a young adult audience

International Nuclear Information System (INIS)

Cavaglia, Marco; Hendry, Martin; Marka, Szabolcs; Reitze, David H; Riles, Keith

2010-01-01

The Laser Interferometer Gravitational-wave Observatory exhibit Astronomy's New Messengers: Listening to the Universe with Gravitational Waves is traveling to colleges, universities, museums and other public institutions throughout the United States. In 2010, an extended version of this exhibit will appear in a New York City venue that is accessible to a large and diverse cross section of the general public. Astronomy's New Messengers primarily communicates with an adolescent and young adult audience, potentially inspiring them into the field of science. Acknowledging that this audience is traditionally a difficult one to attract, the exhibit publicly announces itself in a charismatic fashion to reach its principal goals of broadening the community of people interested in science and encouraging interest in science among young people.

Tools to probe the universe; Des outils pour sonder l'univers

Energy Technology Data Exchange (ETDEWEB)

Lagage, P.O.; Augueres, J.L.; Amiaux, J.; Cara, Ch.; Fontignie, J.; Rio, Y.; Fermon, C.; Pannetier-Lecoeur, M.; De Vismes, A.; Cordier, B.; Fesquet, M.; Ferrando, Ph.; Authier, M.; Pantin, E.; Glicenstein, J.F.; Boulade, O.; Refregier, A.; Stolarczyk, Th.; Agnese, P.; Rodriguez, L.; Agnese, P.; Pigot, C.; Duband, L.; Limousin, O.; Delagnes, E.; Turck-Chieze, S.; Carton, P.H.; Starck, J.L.; Bournaud, F.; Teyssier, R.; Audit, E.; Brun, A.S.; Leca, P.; Menache, Ch.; Pomarede, D.; Thooris, B.; Meis, C.

2009-07-01

This special issue of Clefs CEA journal is entirely devoted to astrophysics and to the exploration and probing of the Universe. The second part of this dossier, described here, makes a status of the tools used to probe the universe: telescopes, imaging spectrometers, data processing and simulation. Content: A - Telescopes of the future: 1. Seeing further out: JWST: looking back on a past 13 billion years old, Space specifics: the learning curve to know-how, Fabricating a corona-graph mask, SVOM, a satellite to detect the explosions of the first stars to be formed in the Universe; 2. Seeing more precisely: SIMBOL-X, pioneering formation flying, ELT/METIS, a 42-meter giant, One hundred telescopes for the CTA arrays; 3. Seeing wider: Euclid, mapping the extragalactic sky, ANTARES: the neutrino, another cosmic messenger; B - The new generation of imaging spectrometers: Observing the Universe in the submillimeter spectral region, The X-ray Universe, Space cryo-coolers, Out in the extreme, tumultuous Universe, Probing the Sun with GOLF-NG, Focus: From light to imagery; C - Data analysis in astrophysics; D - Numerical simulation in astrophysics: Information technology and theoretical predictions in astrophysics, Supercomputers for a better understanding of the Universe, The visualization of astrophysical simulations, Godunov, a numerical platform for education and research

Ultra-sensitive DNA assay based on single-molecule detection coupled with fluorescent quantum dot-labeling and its application to determination of messenger RNA

Energy Technology Data Exchange (ETDEWEB)

Li Li [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Li Xincang [School of Life Sciences, Shandong University, Jinan 250100 (China); Li Lu [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Wang Jinxing [School of Life Sciences, Shandong University, Jinan 250100 (China); Jin Wenrui, E-mail: jwr@sdu.edu.cn [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

2011-01-24

An ultra-sensitive single-molecule detection (SMD) method for quantification of DNA using total internal reflection fluorescence microscopy (TIRFM) coupled with fluorescent quantum dot (QD)-labeling was developed. In this method, the target DNA (tDNA) was captured by the capture DNA immobilized on the silanized coverslip blocked with ethanolamine and bovine serum albumin. Then, the QD-labeled probe DNA was hybridized to the tDNA. Ten fluorescent images of the QD-labeled sandwich DNA hybrids on the coverslip were taken by a high-sensitive CCD. The tDNA was quantified by counting the bright spots on the images using a calibration curve. The LOD of the method was 1 x 10{sup -14} mol L{sup -1}. Several key factors, including image acquirement, fluorescence probe, substrate preparation, noise elimination from solutions and glass coverslips, and nonspecific adsorption and binding of solution-phase detection probes were discussed in detail. The method could be applied to quantify messenger RNA (mRNA) in cells. In order to determine mRNA, double-stranded RNA-DNA hybrids consisting of mRNA and corresponding cDNA were synthesized from the cellular mRNA template using reverse transcription in the presence of reverse transcriptase. After removing the mRNA in the double-stranded hybrids using ribonuclease, cDNA was quantified using the SMD-based TIRFM. Osteopontin mRNA in decidual stromal cells was chosen as the model analyte.

MESSENGER E/V/H GRNS 3 GAMMA RAY SPECTROMETER CALIBDATA V1.0

Data.gov (United States)

National Aeronautics and Space Administration — Abstract ======== This data set consists of the MESSENGER GRS calibrated observations (CDRs) and the reduced data product (RDR). The GRS experiment is a gamma ray...

Mercury's Exosphere During MESSENGER's Second Flyby: Detection of Magnesium and Distinct Distributions of Neutral Species

Science.gov (United States)

McClintock, William E.; Vervack, Ronald J., Jr.; Bradley, E. Todd; Killen, Rosemary M.; Mouawad, Nelly; Sprague, Ann L.; Burger, Matthew H.; Solomon, Sean C.; Izenberg, Noam R.

2009-01-01

During MESSENGER's second Mercury flyby, the Mercury Atmospheric and Surface Composition Spectrometer observed emission from Mercury's neutral exosphere. These observations include the first detection of emission from magnesium. Differing spatial distributions for sodium, calcium, and magnesium were revealed by observations beginning in Mercury's tail region, approximately 8 Mercury radii anti-sunward of the planet, continuing past the nightside, and ending near the dawn terminator. Analysis of these observations, supplemented by observations during the first Mercury flyby as well as those by other MESSENGER instruments, suggests that the distinct spatial distributions arise from a combination of differences in source, transfer, and loss processes.

The structure of plasma-density irregularities in the interplanetary medium

International Nuclear Information System (INIS)

Singleton, D.G.

1975-01-01

The conflict in the literature as to whether the plasma-density spatial spectrum of the irregularities in the interplanetary medium is of Gaussian or power law form is discussed. Particular attention is paid to the interplanetary scintillation effects ascribed to these irregularities. It is shown that the phase-screen theory of scintillations can be invoked to devise a set of critical tests which provide a means of discriminating between the conflicting hypotheses. Differences in the predicted behaviour of the single sensor temporal spectra of the scintillations for the two irregularity forms provide the main tests of the conflicting hypotheses. However, it is also shown that the two hypotheses lead to different forms of the variation of scintillation index with the observing frequency and the solar elongation of the scintillating source. Consideration is given to the optimum conditions for observing the Fourier and Bessel temporal spectra modulation which is due to the Fresnel filtering of the spatial spectrum. Determination of irregularity shape, orientation and motion in terms of this modulation is also discussed. (author)

DENSITY FLUCTUATIONS UPSTREAM AND DOWNSTREAM OF INTERPLANETARY SHOCKS

Energy Technology Data Exchange (ETDEWEB)

Pitňa, A.; Šafránková, J.; Němeček, Z.; Goncharov, O.; Němec, F.; Přech, L. [Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, 180 00 Prague 8 (Czech Republic); Chen, C. H. K. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Zastenker, G. N., E-mail: jana.safrankova@mff.cuni.cz [Space Research Institute of Russian Academy of Sciences, Moscow, Russia, Profsoyuznaya ul. 84/32, Moscow 117997 (Russian Federation)

2016-03-01

Interplanetary (IP) shocks as typical large-scale disturbances arising from processes such as stream–stream interactions or Interplanetary Coronal Mass Ejection (ICME) launching play a significant role in the energy redistribution, dissipation, particle heating, acceleration, etc. They can change the properties of the turbulent cascade on shorter scales. We focus on changes of the level and spectral properties of ion flux fluctuations upstream and downstream of fast forward oblique shocks. Although the fluctuation level increases by an order of magnitude across the shock, the spectral slope in the magnetohydrodynamic range is conserved. The frequency spectra upstream of IP shocks are the same as those in the solar wind (if not spoiled by foreshock waves). The spectral slopes downstream are roughly proportional to the corresponding slopes upstream, suggesting that the properties of the turbulent cascade are conserved across the shock; thus, the shock does not destroy the shape of the spectrum as turbulence passes through it. Frequency spectra downstream of IP shocks often exhibit “an exponential decay” in the ion kinetic range that was earlier reported at electron scales in the solar wind or at ion scales in the interstellar medium. We suggest that the exponential shape of ion flux spectra in this range is caused by stronger damping of the fluctuations in the downstream region.

First Taste of Hot Channel in Interplanetary Space

Science.gov (United States)

Song, H. Q.; Zhang, J.; Chen, Y.; Cheng, X.; Li, G.; Wang, Y. M.

2015-04-01

A hot channel (HC) is a high temperature (˜10 MK) structure in the inner corona first revealed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. Eruptions of HCs are often associated with flares and coronal mass ejections (CMEs). Results of previous studies have suggested that an HC is a good proxy for a magnetic flux rope (MFR) in the inner corona as well as another well known MFR candidate, the prominence-cavity structure, which has a normal coronal temperature (˜1-2 MK). In this paper, we report a high temperature structure (HTS, ˜1.5 MK) contained in an interplanetary CME induced by an HC eruption. According to the observations of bidirectional electrons, high temperature and density, strong magnetic field, and its association with the shock, sheath, and plasma pile-up region, we suggest that the HTS is the interplanetary counterpart of the HC. The scale of the measured HTS is around 14 R ⊙ , and it maintained a much higher temperature than the background solar wind even at 1 AU. It is significantly different from the typical magnetic clouds, which usually have a much lower temperature. Our study suggests that the existence of a corotating interaction region ahead of the HC formed a magnetic container to inhibit expansion of the HC and cool it down to a low temperature.

Automated interplanetary shock detection and its application to Wind observations

Czech Academy of Sciences Publication Activity Database

Krupařová, Oksana; Maksimovic, M.; Šafránková, J.; Němeček, Z.; Santolík, Ondřej; Krupař, Vratislav

2013-01-01

Roč. 118, č. 8 (2013), 4793–4803 ISSN 2169-9380 R&D Projects: GA ČR(CZ) GAP209/12/2394 Institutional support: RVO:68378289 Keywords : Interplanetary shocks * instruments and techniques Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.440, year: 2013 http://onlinelibrary.wiley.com/doi/10.1002/jgra.50468/abstract

Mercury's complex exosphere: results from MESSENGER's third flyby.

Science.gov (United States)

Vervack, Ronald J; McClintock, William E; Killen, Rosemary M; Sprague, Ann L; Anderson, Brian J; Burger, Matthew H; Bradley, E Todd; Mouawad, Nelly; Solomon, Sean C; Izenberg, Noam R

2010-08-06

During MESSENGER's third flyby of Mercury, the Mercury Atmospheric and Surface Composition Spectrometer detected emission from ionized calcium concentrated 1 to 2 Mercury radii tailward of the planet. This measurement provides evidence for tailward magnetospheric convection of photoions produced inside the magnetosphere. Observations of neutral sodium, calcium, and magnesium above the planet's north and south poles reveal altitude distributions that are distinct for each species. A two-component sodium distribution and markedly different magnesium distributions above the two poles are direct indications that multiple processes control the distribution of even single species in Mercury's exosphere.

Mercury's Complex Exosphere: Results from MESSENGER's Third Flyby

Science.gov (United States)

Vervack, Ronald J., Jr.; McClintock, William E.; Killen, Rosemary M.; Sprague, Ann L.; Anderson, Brian J.; Burger, Matthew H.; Bradley, E. Todd; Mouawad, Nelly; Solomon, Sean C.; Izenberg, Noam R.

2010-01-01

During MESSENGER's third flyby of Mercury, the Mercury Atmospheric and Surface Composition Spectrometer detected emission from ionized calcium concentrated 1 to 2 Mercury radii tailward of the planet. This measurement provides evidence for tailward magnetospheric convection of photoions produced inside the magnetosphere. Observations of neutral sodium, calcium, and magnesium above the planet's north and south poles reveal attitude distributions that are distinct for each species. A two-component sodium distribution and markedly different magnesium distributions above the two poles are direct indications that multiple processes control the distribution of even single species in Mercury's exosphere,

Motion of shocks through interplanetary streams

International Nuclear Information System (INIS)

Burlaga, L.F.; Scudder, J.D.

1975-01-01

A model for the motion of flare-generated shocks through interplanetary streams is presented, illustrating the effects of a stream-shock interaction on the shock strength and geometry. It is a gas dynamic calculation based on Whitham's method and on an empirical approximation for the relevant characteristics of streams. The results show that the Mach number of a shock can decrease appreciably to near unity in the interaction region ahead of streams and that the interaction of a spherically symmetric shock with a spiral-shaped corotating stream can cause significant distortions of the initial shock front geometry. The geometry of the February 15--16, 1967, shock discussed by Lepping and Chao (1972) is qualitatively explained by this model

A Contemporary, Laboratory-Intensive Course on Messenger RNA Transcription and Processing

Science.gov (United States)

Carson, Sue; Miller, Heather

2012-01-01

Messenger ribonucleic acid (mRNA) plays a pivotal role in the central dogma of molecular biology. Importantly, molecular events occurring during and after mRNA synthesis have the potential to create multiple proteins from one gene, leading to some of the remarkable protein diversity that genomes hold. The North Carolina State University…

MESSENGER E/V/H MASCS 5 VIRS DERIVED ANALYSIS DATA V2.0

Data.gov (United States)

National Aeronautics and Space Administration — Abstract ======== This data set consists of the MESSENGER MASCS VIRS derived analysis product, also known as the DAP. The DAP is a 500 meter per pixel mosaic map of...

MESSENGER E/V/H MASCS 5 VIRS DERIVED ANALYSIS DATA V1.0

Data.gov (United States)

National Aeronautics and Space Administration — Abstract ======== This data set consists of the MESSENGER MASCS VIRS derived analysis product, also known as the DAP. The DAP is a 500 meter per pixel mosaic map of...

Radio emission from coronal and interplanetary shocks

International Nuclear Information System (INIS)

Cane, H.V.

1987-01-01

Observational data on coronal and interplanetary (IP) type II burst events associated with shock-wave propagation are reviewed, with a focus on the past and potential future contributions of space-based observatories. The evidence presented by Cane (1983 and 1984) in support of the hypothesis that the coronal (metric) and IP (kilometric) bursts are due to different shocks is summarized, and the fast-drift kilometric events seen at the same time as metric type II bursts (and designated shock-accelerated or shock-associated events) are characterized. The need for further observations at 0.5-20 MHz is indicated. 20 references

Effect of Interplanetary Magnetic Field and Disturb Storm Time on H ...

Indian Academy of Sciences (India)

E). We also study the effect of vertical component of interplanetary magnetic field (IMF) on the variation of the magnitude of H component during storm time of April, July and. November 2004. Results show that before sudden storm commencement. (SSC) time magnitude of H component and IMF show smooth variation but.

On the twists of interplanetary magnetic flux ropes observed at 1 AU

Science.gov (United States)

Wang, Yuming; Zhuang, Bin; Hu, Qiang; Liu, Rui; Shen, Chenglong; Chi, Yutian

2016-10-01

Magnetic flux ropes (MFRs) are one kind of fundamental structures in the solar/space physics and involved in various eruption phenomena. Twist, characterizing how the magnetic field lines wind around a main axis, is an intrinsic property of MFRs, closely related to the magnetic free energy and stableness. Although the effect of the twist on the behavior of MFRs had been widely studied in observations, theory, modeling, and numerical simulations, it is still unclear how much amount of twist is carried by MFRs in the solar atmosphere and in heliosphere and what role the twist played in the eruptions of MFRs. Contrasting to the solar MFRs, there are lots of in situ measurements of magnetic clouds (MCs), the large-scale MFRs in interplanetary space, providing some important information of the twist of MFRs. Thus, starting from MCs, we investigate the twist of interplanetary MFRs with the aid of a velocity-modified uniform-twist force-free flux rope model. It is found that most of MCs can be roughly fitted by the model and nearly half of them can be fitted fairly well though the derived twist is probably overestimated by a factor of 2.5. By applying the model to 115 MCs observed at 1 AU, we find that (1) the twist angles of interplanetary MFRs generally follow a trend of about 0.6l/R radians, where l/R is the aspect ratio of a MFR, with a cutoff at about 12π radians AU-1, (2) most of them are significantly larger than 2.5π radians but well bounded by 2l/R radians, (3) strongly twisted magnetic field lines probably limit the expansion and size of MFRs, and (4) the magnetic field lines in the legs wind more tightly than those in the leading part of MFRs. These results not only advance our understanding of the properties and behavior of interplanetary MFRs but also shed light on the formation and eruption of MFRs in the solar atmosphere. A discussion about the twist and stableness of solar MFRs are therefore given.

MESSENGER E/V/H GRNS 2 GAMMA RAY SPECTROMETER RAW DATA V1.0

Data.gov (United States)

National Aeronautics and Space Administration — Abstract ======== This data set consists of the MESSENGER GRS uncalibrated observations, also known as EDRs. The GRS experiment is a gamma ray spectrometer designed...

EISCAT measurements of solar wind velocity and the associated level of interplanetary scintillation

Directory of Open Access Journals (Sweden)

R. A. Fallows

2002-09-01

Full Text Available A relative scintillation index can be derived from EISCAT observations of Interplanetary Scintillation (IPS usually used to study the solar wind velocity. This provides an ideal opportunity to compare reliable measurements of the solar wind velocity derived for a number of points along the line-of-sight with measurements of the overall level of scintillation. By selecting those occasions where either slow- or fast-stream scattering was dominant, it is shown that at distances from the Sun greater than 30 RS , in both cases the scintillation index fell with increasing distance as a simple power law, typically as R-1.7. The level of scintillation for slow-stream scattering is found to be 2.3 times the level for fast-stream scattering.Key words. Interplanetary physics (solar wind plasma

Evidence of scattering effects on the sizes of interplanetary Type III radio bursts

Science.gov (United States)

Steinberg, J. L.; Hoang, S.; Dulk, G. A.

1985-01-01

An analysis is conducted of 162 interplanetary Type III radio bursts; some of these bursts have been observed in association with fast electrons and Langmuir wave events at 1 AU and, in addition, have been subjected to in situ plasma parameter measurements. It is noted that the sizes of burst sources are anomalously large, compared to what one would anticipate on the basis of the interplanetary plasma density distribution, and that the variation of source size with frequency, when compared with the plasma frequency variation measured in situ, implies that the source sizes expand with decreasing frequency to fill a cone whose apex is at the sun. It is also found that some local phenomenon near the earth controls the apparent size of low frequency Type III sources.

Public information in radiation emergencies - the messenger, the public and the message

International Nuclear Information System (INIS)

Lackey, J.

1999-01-01

This paper is based on experience as a lecturer on emergency planning courses in east and west Europe, in the USA and in Hong Kong. The complex language of radiation protection confuses the public and so the messenger must avoid unnecessary jargon. In some cases the messenger may have little experience of speaking in public but this can be remedied in exercise and the fear of speaking in public may be reduced. Communication would be more efficient and possibly cause less anxiety if the public was better educated about ionizing radiation. A European initiative is described and the author' s revision of the CEC teacher's manual is reported. The debate over the linear-no-threshold model seems to undermine the credibility of the radiological protection message. The author proposes that a dose threshold should be set, preferably internationally, so those individual doses below threshold could be excluded from records and research effort redirected to more hazardous factors. Copyright (1999) Australasian Radiation Protection Society Inc

Effect of Thymine Starvation on Messenger Ribonucleic Acid Synthesis in Escherichia coli

Science.gov (United States)

Luzzati, Denise

1966-01-01

Luzzati, Denise (Institut de Biologie Physico-Chimique, Paris, France). Effect of thymine starvation on messenger ribonucleic acid synthesis in Escherichia coli. J. Bacteriol. 92:1435–1446. 1966.—During the course of thymine starvation, the rate of synthesis of messenger ribonucleic acid (mRNA, the rapidly labeled fraction of the RNA which decays in the presence of dinitrophenol or which hybridizes with deoxyribonucleic acid) decreases exponentially, in parallel with the viability of the thymine-starved bacteria. The ability of cell-free extracts of starved bacteria to incorporate ribonucleoside triphosphates into RNA was determined; it was found to be inferior to that of extracts from control cells. The analysis of the properties of cell-free extracts of starved cells shows that their decreased RNA polymerase activity is the consequence of a modification of their deoxyribonucleic acid, the ability of which to serve as a template for RNA polymerase decreases during starvation. PMID:5332402

Global Distribution of Mercury's Neutrals from MESSENGER Measurements Combined with a Tomographic Method

Science.gov (United States)

Sarantos, Menelaos; McClintock, Bill; Vervack, Ron, Jr.; Killen, Rosemary; Merkel, Aimee; Slavin, James; Solomon, Sean C.

2011-01-01

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft entered orbit about Mercury on March 18, 2011. Since then, the Ultraviolet and Visible Spectrometer (UVVS) onboard this spacecraft has been observing Mercury's collisionless exosphere. We present measurements by MESSENGER UVVS of the sodium, calcium, and magnesium distributions that were obtained during multiple passes through the tail over a period of one month. Global maps of the exosphere were constructed daily from such measurements using a recently developed tomographic technique. During this period, Mercury moved towards the Sun from being about 0.44 astronomical units (AU) to approximately 0.32 AU from the Sun. Hence, our reconstructions provide information about the three-dimensional structure of the exosphere, the source processes for these species, and their dependence with orbital distance during the entire in-leg of Mercury's orbit.

Solar sail time-optimal interplanetary transfer trajectory design

International Nuclear Information System (INIS)

Gong Shengpin; Gao Yunfeng; Li Junfeng

2011-01-01

The fuel consumption associated with some interplanetary transfer trajectories using chemical propulsion is not affordable. A solar sail is a method of propulsion that does not consume fuel. Transfer time is one of the most pressing problems of solar sail transfer trajectory design. This paper investigates the time-optimal interplanetary transfer trajectories to a circular orbit of given inclination and radius. The optimal control law is derived from the principle of maximization. An indirect method is used to solve the optimal control problem by selecting values for the initial adjoint variables, which are normalized within a unit sphere. The conditions for the existence of the time-optimal transfer are dependent on the lightness number of the sail and the inclination and radius of the target orbit. A numerical method is used to obtain the boundary values for the time-optimal transfer trajectories. For the cases where no time-optimal transfer trajectories exist, first-order necessary conditions of the optimal control are proposed to obtain feasible solutions. The results show that the transfer time decreases as the minimum distance from the Sun decreases during the transfer duration. For a solar sail with a small lightness number, the transfer time may be evaluated analytically for a three-phase transfer trajectory. The analytical results are compared with previous results and the associated numerical results. The transfer time of the numerical result here is smaller than the transfer time from previous results and is larger than the analytical result.

Monte Carlo Modeling of Sodium in Mercury's Exosphere During the First Two MESSENGER Flybys

Science.gov (United States)

Burger, Matthew H.; Killen, Rosemary M.; Vervack, Ronald J., Jr.; Bradley, E. Todd; McClintock, William E.; Sarantos, Menelaos; Benna, Mehdi; Mouawad, Nelly

2010-01-01

We present a Monte Carlo model of the distribution of neutral sodium in Mercury's exosphere and tail using data from the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft during the first two flybys of the planet in January and September 2008. We show that the dominant source mechanism for ejecting sodium from the surface is photon-stimulated desorption (PSD) and that the desorption rate is limited by the diffusion rate of sodium from the interior of grains in the regolith to the topmost few monolayers where PSD is effective. In the absence of ion precipitation, we find that the sodium source rate is limited to approximately 10(exp 6) - 10(exp 7) per square centimeter per second, depending on the sticking efficiency of exospheric sodium that returns to the surface. The diffusion rate must be at least a factor of 5 higher in regions of ion precipitation to explain the MASCS observations during the second MESSENGER f1yby. We estimate that impact vaporization of micrometeoroids may provide up to 15% of the total sodium source rate in the regions observed. Although sputtering by precipitating ions was found not to be a significant source of sodium during the MESSENGER flybys, ion precipitation is responsible for increasing the source rate at high latitudes through ion-enhanced diffusion.

Effect of Interplanetary Magnetic Field and Disturb Storm Time on H ...

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy; Volume 29; Issue 1-2. Effect of Interplanetary Magnetic Field and Disturb Storm Time on H Component. Rajni Devi Smita Dubey Shailendra Saini Babita Devi Ajay Dhar S. K. Vijay A. K. Gwal. Volume 29 Issue 1-2 March-June 2008 pp 281-286 ...

Relationship of Interplanetary Shock Micro and Macro Characteristics: A Wind Study

Science.gov (United States)

Szabo, Adam; Koval, A

2008-01-01

The non-linear least squared MHD fitting technique of Szabo 11 9941 has been recently further refined to provide realistic confidence regions for interplanetary shock normal directions and speeds. Analyzing Wind observed interplanetary shocks from 1995 to 200 1, macro characteristics such as shock strength, Theta Bn and Mach numbers can be compared to the details of shock micro or kinetic structures. The now commonly available very high time resolution (1 1 or 22 vectors/sec) Wind magnetic field data allows the precise characterization of shock kinetic structures, such as the size of the foot, ramp, overshoot and the duration of damped oscillations on either side of the shock. Detailed comparison of the shock micro and macro characteristics will be given. This enables the elucidation of shock kinetic features, relevant for particle energization processes, for observations where high time resolution data is not available. Moreover, establishing a quantitative relationship between the shock micro and macro structures will improve the confidence level of shock fitting techniques during disturbed solar wind conditions.

Scaling exponents of the velocity structure functions in the interplanetary medium

Directory of Open Access Journals (Sweden)

V. Carbone

Full Text Available We analyze the scaling exponents of the velocity structure functions, obtained from the velocity fluctuations measured in the interplanetary space plasma. Using the expression for the energy transfer rate which seems the most relevant in describing the evolution of the pseudo-energy densities in the interplanetary medium, we introduce an energy cascade model derived from a simple fragmentation process, which takes into account the intermittency effect. In the absence and in the presence of the large-scale magnetic field decorrelation effect the model reduces to the fluid and the hydromagnetic p-model, respectively. We show that the scaling exponents of the q-th power of the velocity structure functions, as obtained by the model in the absence of the decorrelation effect, furnishes the best-fit to the data analyzed from the Voyager 2 velocity field measurements at 8.5 AU. Our results allow us to hypothesize a new kind of scale-similarity for magnetohydrodynamic turbulence when the decorrelation effect is at work, related to the fourth-order velocity structure function.

Geometrical Relationship Between Interplanetary Flux Ropes and Their Solar Sources

Science.gov (United States)

Marubashi, K.; Akiyama, S.; Yashiro, S.; Gopalswamy, N.; Cho, K.-S.; Park, Y.-D.

2015-05-01

We investigated the physical connection between interplanetary flux ropes (IFRs) near Earth and coronal mass ejections (CMEs) by comparing the magnetic field structures of IFRs and CME source regions. The analysis is based on the list of 54 pairs of ICMEs (interplanetary coronal mass ejections) and CMEs that are taken to be the most probable solar source events. We first attempted to identify the flux rope structure in each of the 54 ICMEs by fitting models with a cylinder and torus magnetic field geometry, both with a force-free field structure. This analysis determined the possible geometries of the identified flux ropes. Then we compared the flux rope geometries with the magnetic field structure of the solar source regions. We obtained the following results: (1) Flux rope structures are seen in 51 ICMEs out of the 54. The result implies that all ICMEs have an intrinsic flux rope structure, if the three exceptional cases are attributed to unfavorable observation conditions. (2) It is possible to find flux rope geometries with the main axis orientation close to the orientation of the magnetic polarity inversion line (PIL) in the solar source regions, the differences being less than 25°. (3) The helicity sign of an IFR is strongly controlled by the location of the solar source: flux ropes with positive (negative) helicity are associated with sources in the southern (northern) hemisphere (six exceptions were found). (4) Over two-thirds of the sources in the northern hemisphere are concentrated along PILs with orientations of 45° ± 30° (measured clockwise from the east), and over two-thirds in the southern hemisphere along PILs with orientations of 135° ± 30°, both corresponding to the Hale boundaries. These results strongly support the idea that a flux rope with the main axis parallel to the PIL erupts in a CME and that the erupted flux rope propagates through the interplanetary space with its orientation maintained and is observed as an IFR.

Interplanetary Magnetic Field and Plasma Values Related to Hildcaas Events

Science.gov (United States)

Prestes, A.; Serra, S. L.; Vieira, L. A.

2013-05-01

In this work we investigate the interplanetary conditions during the occurrence of 150 HILDCAAs/QUASI-HILDCAAs events occurred between 1998 and 2007. These events were chosen by following strictly the selection criteria for this kind of phenomena and with some criteria flexible. Among the criteria used to characterize events HILDCAAs, the criterion that considers "the AE values never dropped below 200 nT for more than 2 h at a time" was more restrictive, thus only this was modified by changing from 2 to 4 hours the period in which the AE value can't be below 200 nT. In the interplanetary medium, HILDCAAs are associated with high speed solar wind streams, which are frequently embedded with alfvénic fluctuations. At the Sun, these high speed streams are originated in coronal holes. The distribution of events HILDCAAs/quasi-HILDCAAs along the solar cycle shows a pattern of double peak, a less intense around the maximum of the sunspot cycle and other intense in the descending phase, similar to the distribution of low-latitude coronal holes. For each one of the selected events we have found the most probable value of interplanetary magnetic field and plasma. The average values of AE, AU, AL and Dst indices, the density and temperature of the solar wind protons, the solar wind speed, the Bz component of the IMF, the IMF intensity, dynamic pressure and factor beta, among all the 150 events HILDCAAs/quasi-HILDCAAs, were: AE (344.5 ± 65.0 nT), AU (131.0 ± 33.0 nT), AL (-213.7 ± 51.2 nT), Dst (-25.8 ± 12.2 nT), Density (5,0 ± 1,8 cm-3), Temperature (151269.5 ± 48907.7 K), |V| (538.2 ± 83.3 km/s) Bz (-0.71 ± 1.02 nT), |B| (6.7 ± 1.4 nT) pressure (2.6 ± 0.7 nPa) and Beta (0.66 ± 0.27).

Mercury's Hollows: New Information on Distribution and Morphology from MESSENGER Observations at Low Altitude

Science.gov (United States)

Blewett, D. T.; Stadermann, A. C.; Chabot, N. L.; Denevi, B. W.; Ernst, C. M.; Peplowski, P. N.

2014-12-01

MESSENGER's orbital mission at Mercury led to the discovery of an unusual landform not known from other airless rocky bodies of the Solar System. Hollows are irregularly shaped, shallow, rimless depressions, often occurring in clusters and with high-reflectance interiors and halos. The fresh appearance of hollows suggests that they are relatively young features. For example, hollows are uncratered, and talus aprons downslope of hollows in certain cases appear to be covering small impact craters (100-200 in diameter). Hence, some hollows may be actively forming at present. The characteristics of hollows are suggestive of formation via destruction of a volatile-bearing phase (possibly one or more sulfides) through solar heating, micrometeoroid bombardment, and/or ion impact. Previous analysis showed that hollows are associated with low-reflectance material (LRM), a color unit identified from global color images. The material hosting hollows has often been excavated from depth by basin or crater impacts. Hollows are small features (tens of meters to several kilometers), so their detection and characterization with MESSENGER's global maps have been limited. MESSENGER's low-altitude orbits provide opportunities for collection of images at high spatial resolutions, which reveal new occurrences of hollows and offer views of hollows with unprecedented detail. As of this writing, we have examined more than 21,000 images with pixel sizes Shadow-length measurements were made on 280 images, yielding the depths of 1343 individual hollows. The mean depth is 30 m, with a standard deviation of 17 m. We also explored correlations between the geographic locations of hollows and maps provided by the MESSENGER geochemical sensors (X-Ray, Gamma-Ray, and Neutron Spectrometers), including the abundances of Al/Si, Ca/Si, Fe/Si, K, Mg/Si, and S/Si, as well as total neutron cross-section. No clear compositional trends emerged; it is likely that any true compositional preference for terrain

Audience and Witnessing: Research into Dramatherapy using Vignettes and aMSN Messenger

Science.gov (United States)

Jones, Phil

2008-01-01

This article describes the process of research undertaken to examine therapists' responses to the concept of the core processes of change in dramatherapy. The research uses a combination of vignette description and analysis using aMSN messenger. The article describes the theoretical underpinning and rationale to the approach, and the…

Multiple spacecraft observations of interplanetary shocks: characteristics of the upstream ulf turbulence

International Nuclear Information System (INIS)

Russell, C.T.; Smith, E.J.; Tsurutani, B.T.; Gosling, J.T.; Bame, S.J.

1982-01-01

All interplanetary shocks observed by ISEE-3 and either ISEE-1 or ISEE-2 or both in 1978 and 1979 are examined for evidence of upstream waves. In order to characterize the properties of these shocks it is necessary to determine accurate shock normals. We invert an overdetermined set of equations to obtain shock normals, velocities and error estimates for all these shocks. Tests of the method indicate it is quite reliable. Using these normals we then calculate the Mach number and angle between the interplanetary magnetic field and the shock normal for each shock. These parameters allow us to separate the upstream waves into two classes: whistler-mode precursors which occur at low Mach numbers and upstream turbulence whose amplitude at Mach numbers greater than 1.5 is controlled by the angle of the field to the shock normal. The former waves are right-hand circularly polarized and quite monochromatic. The latter waves are more linearly polarized and have a broadband featureless spectrum

EVIDENCE OF CONFINEMENT OF SOLAR-ENERGETIC PARTICLES TO INTERPLANETARY MAGNETIC FIELD LINES

International Nuclear Information System (INIS)

Chollet, E. E.; Giacalone, J.

2011-01-01

We present new observations of solar-energetic particles (SEPs) associated with impulsive solar flares that show evidence for their confinement to interplanetary magnetic field lines. Some SEP events exhibit intermittent intensity dropouts because magnetic field lines filled with and empty of particle flux mix together. The edges of these dropouts are observed to be very sharp, suggesting that particles cannot easily move from a filled to an empty field line in the time available during their transport from the Sun. In this paper, we perform high time-resolution observations of intensity fall-off at the edges of observed SEP dropouts in order to look for signatures of particle motion off field lines. However, the statistical study is dominated by one particularly intense event. The inferred length scale of the intensity decay is comparable to the gyroradii of the particles, suggesting that particles only rarely scatter off magnetic field lines during interplanetary transport.

Emotion elicitor or emotion messenger? Subliminal priming reveals two faces of facial expressions.

Science.gov (United States)

Ruys, Kirsten I; Stapel, Diederik A

2008-06-01

Facial emotional expressions can serve both as emotional stimuli and as communicative signals. The research reported here was conducted to illustrate how responses to both roles of facial emotional expressions unfold over time. As an emotion elicitor, a facial emotional expression (e.g., a disgusted face) activates a response that is similar to responses to other emotional stimuli of the same valence (e.g., a dirty, nonflushed toilet). As an emotion messenger, the same facial expression (e.g., a disgusted face) serves as a communicative signal by also activating the knowledge that the sender is experiencing a specific emotion (e.g., the sender feels disgusted). By varying the duration of exposure to disgusted, fearful, angry, and neutral faces in two subliminal-priming studies, we demonstrated that responses to faces as emotion elicitors occur prior to responses to faces as emotion messengers, and that both types of responses may unfold unconsciously.

Solar Probe Plus: Mission design challenges and trades

Science.gov (United States)

Guo, Yanping

2010-11-01

NASA plans to launch the first mission to the Sun, named Solar Probe Plus, as early as 2015, after a comprehensive feasibility study that significantly changed the original Solar Probe mission concept. The original Solar Probe mission concept, based on a Jupiter gravity assist trajectory, was no longer feasible under the new guidelines given to the mission. A complete redesign of the mission was required, which called for developing alternative trajectories that excluded a flyby of Jupiter. Without the very powerful gravity assist from Jupiter it was extremely difficult to get to the Sun, so designing a trajectory to reach the Sun that is technically feasible under the new mission guidelines became a key enabler to this highly challenging mission. Mission design requirements and challenges unique to this mission are reviewed and discussed, including various mission scenarios and six different trajectory designs utilizing various planetary gravity assists that were considered. The V 5GA trajectory design using five Venus gravity assists achieves a perihelion of 11.8 solar radii ( RS) in 3.3 years without any deep space maneuver (DSM). The V 7GA trajectory design reaches a perihelion of 9.5 RS using seven Venus gravity assists in 6.39 years without any DSM. With nine Venus gravity assists, the V 9GA trajectory design shows a solar orbit at inclination as high as 37.9° from the ecliptic plane can be achieved with the time of flight of 5.8 years. Using combined Earth and Venus gravity assists, as close as 9 RS from the Sun can be achieved in less than 10 years of flight time at moderate launch C3. Ultimately the V 7GA trajectory was chosen as the new baseline mission trajectory. Its design allowing for science investigation right after launch and continuing for nearly 7 years is unprecedented for interplanetary missions. The redesigned Solar Probe Plus mission is not only feasible under the new guidelines but also significantly outperforms the original mission concept

North-South asymmetry of interplanetary plasma and solar parameters

International Nuclear Information System (INIS)

El-Borie, M. A.

2001-01-01

Data of interplanetary plasma (field magnitude, solar wind speed, ion plasma density and temperature) and solar parameters (sunspot number, solar radio flux, and geomagnetic index) over the period 1965-1991, have been used to examine the asymmetry between the solar field north and south of the heliospheric current sheet (HCS). The dependence of N-S asymmetry of field magnitude (B) upon the interplanetary solar polarities is statistically insignificant. There is no clear indication for the presence of N-S asymmetry in the grand-average field magnitude over the solar cycles. During the period 1981-89 (qA<0; negative solar polarity state), the solar plasma was more dense and cooler south of the HCS than north of it. The solar flux component of toward field vector is larger in magnitude than those of away field vector during the qA<0 epoch, and no asymmetry observed in the qA<0 epoch. Furthermore, the sign of the N-S asymmetry in the solar activity depends positively upon the solar polarity state. In addition, it was studied the N-S asymmetry of solar parameters near the HCS, throughout the periods of northern and southern hemispheres were more active than the other. Some asymmetries (with respect to the HCS) in plasma parameters existed during the periods of southern hemisphere predominance

Gravity, Topography, and Magnetic Field of Mercury from Messenger

Science.gov (United States)

Neumann, Gregory A.; Solomon, Sean C.; Zuber, Maria T.; Phillips, Roger J.; Barnouin, Olivier; Ernst, Carolyn; Goosens, Sander; Hauck, Steven A., II; Head, James W., III; Johnson, Catherine L.;

MESSENGER, MErcury: Surface, Space ENvironment, GEochemistry, and Ranging; A Mission to Orbit and Explore the Planet Mercury

Science.gov (United States)

1999-01-01

MESSENGER is a scientific mission to Mercury. Understanding this extraordinary planet and the forces that have shaped it is fundamental to understanding the processes that have governed the formation, evolution, and dynamics of the terrestrial planets. MESSENGER is a MErcury Surface, Space ENvironment, GEochemistry and Ranging mission to orbit Mercury for one Earth year after completing two flybys of that planet following two flybys of Venus. The necessary flybys return significant new data early in the mission, while the orbital phase, guided by the flyby data, enables a focused scientific investigation of this least-studied terrestrial planet. Answers to key questions about Mercury's high density, crustal composition and structure, volcanic history, core structure, magnetic field generation, polar deposits, exosphere, overall volatile inventory, and magnetosphere are provided by an optimized set of miniaturized space instruments. Our goal is to gain new insight into the formation and evolution of the solar system, including Earth. By traveling to the inner edge of the solar system and exploring a poorly known world, MESSENGER fulfills this quest.

Long-term Regularities in Distribution of Global Solar and Interplanetary Magnetic Fields

Czech Academy of Sciences Publication Activity Database

Ambrož, Pavel

2013-01-01

Roč. 37, č. 2 (2013), s. 637-642 ISSN 1845-8319. [Hvar Astrophysical Colloquium /12./. Hvar, 03.09.2012-07.09.2012] R&D Projects: GA AV ČR IAA300030808 Institutional support: RVO:67985815 Keywords : interplanetary magnetic field * solar wind Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

Multi-Messenger Astronomy: White Dwarf Binaries, LISA and GAIA

Science.gov (United States)

Bueno, Michael; Breivik, Katelyn; Larson, Shane L.

2017-01-01

The discovery of gravitational waves has ushered in a new era in astronomy. The low-frequency band covered by the future LISA detector provides unprecedented opportunities for multi-messenger astronomy. With the Global Astrometric Interferometer for Astrophysics (GAIA) mission, we expect to discover about 1,000 eclipsing binary systems composed of a WD and a main sequence star - a sizeable increase from the approximately 34 currently known binaries of this type. In advance of the first GAIA data release and the launch of LISA within the next decade, we used the Binary Stellar Evolution (BSE) code simulate the evolution of White Dwarf Binaries (WDB) in a fixed galaxy population of about 196,000 sources. Our goal is to assess the detectability of a WDB by LISA and GAIA using the parameters from our population synthesis, we calculate GW strength h, and apparent GAIA magnitude G. We can then use a scale factor to make a prediction of how many multi- messenger sources we expect to be detectable by both LISA and GAIA in a galaxy the size of the Milky Way. We create binaries 10 times to ensure randomness in distance assignment and average our results. We then determined whether or not astronomical chirp is the difference between the total chirp and the GW chirp. With Astronomical chirp and simulations of mass transfer and tides, we can gather more information about the internal astrophysics of stars in ultra-compact binary systems.

VARIATIONS OF THE MUON FLUX AT SEA LEVEL ASSOCIATED WITH INTERPLANETARY ICMEs AND COROTATING INTERACTION REGIONS

Energy Technology Data Exchange (ETDEWEB)

Augusto, C. R. A.; Kopenkin, V.; Navia, C. E.; Tsui, K. H.; Shigueoka, H. [Instituto de Fisica, Universidade Federal Fluminense, 24210-346, Niteroi, RJ (Brazil); Fauth, A. C.; Kemp, E.; Manganote, E. J. T. [Instituto de Fisica Gleb Wathagin, Universidade Estadual de Campinas, Campinas, SP (Brazil); Leigui de Oliveira, M. A. [Centro de Ciencias Naturais e Humanas da Universidade Federal do ABC, Santo Andre, SP (Brazil); Miranda, P.; Ticona, R.; Velarde, A. [Instituto de Investigaciones Fisicas, UMSA, La Paz Bolivia (United States)

2012-11-10

We present the results of an ongoing survey on the association between the muon flux variation at ground level (3 m above sea level) registered by the Tupi telescopes (Niteri-Brazil, 22.{sup 0}9S, 43.{sup 0}2W, 3 m) and the Earth-directed transient disturbances in the interplanetary medium propagating from the Sun (such as coronal mass ejections (CME), and corotating interaction regions (CIRs)). Their location inside the South Atlantic Anomaly region enables the muon telescopes to achieve a low rigidity of response to primary and secondary charged particles. The present study is primarily based on experimental events obtained by the Tupi telescopes in the period from 2010 August to 2011 December. This time period corresponds to the rising phase of solar cycle 24. The Tupi events are studied in correlation with data obtained by space-borne detectors (SOHO, ACE, GOES). Identification of interplanetary structures and associated solar activity was based on the nomenclature and definitions given by the satellite observations, including an incomplete list of possible interplanetary shocks observed by the CELIAS/MTOF Proton Monitor on the Solar and Heliospheric Observatory (SOHO) spacecraft. Among 29 experimental events reported in the present analysis, there are 15 possibly associated with the CMEs and sheaths, and 3 events with the CIRs (forward or reverse shocks); the origin of the remaining 11 events has not been determined by the satellite detectors. We compare the observed time (delayed or anticipated) of the muon excess (positive or negative) signal on Earth (the Tupi telescopes) with the trigger time of the interplanetary disturbances registered by the satellites located at Lagrange point L1 (SOHO and ACE). The temporal correlation of the observed ground-based events with solar transient events detected by spacecraft suggests a real physical connection between them. We found that the majority of observed events detected by the Tupi experiment were delayed in

Meetings: Interplanetary GPS

Science.gov (United States)

2018-01-01

A system onboard the International Space Station found its location in the cosmos by detecting periodic x-ray signals from neutron stars—a technique that could eventually work for distant space probes.

Autonomous aerobraking for low-cost interplanetary missions

Science.gov (United States)

Carrelli, David; O'Shaughnessy, Daniel; Strikwerda, Thomas; Kaidy, James; Prince, Jill; Powell, Richard

2014-01-01

Aerobraking has previously been used to reduce the propellant required to deliver an orbiter to its desired final orbit. In principle, aerobraking should be possible around any target planet or moon having sufficient atmosphere to permit atmospheric drag to provide a portion of the mission ΔV, in lieu of supplying all of the required ΔV propulsively. The spacecraft is flown through the upper atmosphere of the target using multiple passes, ensuring that the dynamic pressure and thermal loads remain within the spacecraft's design parameters. NASA has successfully conducted aerobraking operations four times, once at Venus and three times at Mars. While aerobraking reduces the fuel required, it does so at the expense of time (typically 3-6 months), continuous Deep Space Network (DSN) coverage, and a large ground staff. These factors can result in aerobraking being a very expensive operational phase of the mission. However, aerobraking has matured to the point that much of the daily operation could potentially be performed autonomously onboard the spacecraft, thereby reducing the required ground support and attendant aerobraking related costs. To facilitate a lower-risk transition from ground processing to an autonomous capability, the NASA Engineering and Safety Center (NESC) has assembled a team of experts in aerobraking and interplanetary guidance and control to develop a high-fidelity, flight-like simulation. This simulation will be used to demonstrate the overall feasibility while exploring the potential for staff and DSN coverage reductions that autonomous aerobraking might provide. This paper reviews the various elements of autonomous aerobraking and presents an overview of the various models and algorithms that must be transformed from the current ground processing methodology to a flight-like environment. Additionally the high-fidelity flight software test bed, being developed from models used in a recent interplanetary mission, will be summarized.

Laboratory simulation of interplanetary ultraviolet radiation (broad spectrum) and its effects on Deinococcus radiodurans

Science.gov (United States)

Paulino-Lima, Ivan Gláucio; Pilling, Sérgio; Janot-Pacheco, Eduardo; de Brito, Arnaldo Naves; Barbosa, João Alexandre Ribeiro Gonçalves; Leitão, Alvaro Costa; Lage, Claudia de Alencar Santos

2010-08-01

The radiation-resistant bacterium Deinococcus radiodurans was exposed to a simulated interplanetary UV radiation at the Brazilian Synchrotron Light Laboratory (LNLS). Bacterial samples were irradiated on different substrates to investigate the influence of surface relief on cell survival. The effects of cell multi-layers were also investigated. The ratio of viable microorganisms remained virtually the same (average 2%) for integrated doses from 1.2 to 12 kJ m -2, corresponding to 16 h of irradiation at most. The asymptotic profiles of the curves, clearly connected to a shielding effect provided by multi-layering cells on a cavitary substrate (carbon tape), means that the inactivation rate may not change significantly along extended periods of exposure to radiation. Such high survival rates reinforce the possibility of an interplanetary transfer of viable microbes.

Possible concepts for an in situ Saturn probe mission

Science.gov (United States)

Coustenis, Athena; Lebreton, Jean-Pierre; Mousis, Olivier; Atkinson, David H.; Lunine, Jonathan I.; Reh, Kim R.; Fletcher, Leigh N.; Simon-Miller, Amy A.; Atreya, Sushil; Brinckerhoff, William B.; Cavalie, Thibault; Colaprete, Anthony; Gautier, Daniel; Guillot, Tristan; Mahaffy, Paul R.; Marty, Bernard; Morse, Andy; Sims, Jon; Spilker, Tom; Spilker, Linda

2014-05-01

In situ exploration of Saturn's atmosphere would bring insights in two broad themes: the formation history of our solar system and the processes at play in planetary atmospheres. The science case for in situ measurements at Saturn are developed in [1] and two companion abstracts (see Mousis et al., and Atkinson et al.). They are summarized here. Measurements of Saturn's bulk chemical and isotopic composition would place important constraints on the volatile reservoirs in the protosolar nebula and hence on the formation mechanisms. An in situ probe, penetrating from the upper atmosphere (μbar level) into the convective weather layer to a minimum depth of 10 bar, would also contribute to our knowledge of Saturn's atmospheric structure, dynamics, composition, chemistry and cloud-forming processes. Different mission architectures are envisaged, all based on an entry probe that would descend through Saturn's stratosphere and troposphere under parachute down to a minimum of 10 bars [1]. Future studies will focus on the trade-offs between science return and the added design complexity of a probe that could operate at pressures larger than 10 bars. Accelerometry measurements may also be performed during the entry phase in the higher part of the stratosphere prior to starting measurements under parachute. A carrier system would be required to deliver the probe along its interplanetary trajectory to the desired atmospheric entry point at Saturn. The entry site would be carefully selected. Three possible mission configurations are currently under study (with different risk/cost trades): • Configuration 1: Probe + Carrier. After probe delivery, the carrier would follow its path and be destroyed during atmospheric entry, but could perform pre-entry science. The carrier would not be used as a radio relay, but the probe would transmit its data to the ground system via a direct-to-Earth (DTE) RF link; • Configuration 2: Probe + Carrier/Relay. The probe would detach from the

Laser altimeter observations from MESSENGER's first Mercury flyby.

Science.gov (United States)

Zuber, Maria T; Smith, David E; Solomon, Sean C; Phillips, Roger J; Peale, Stanton J; Head, James W; Hauck, Steven A; McNutt, Ralph L; Oberst, Jürgen; Neumann, Gregory A; Lemoine, Frank G; Sun, Xiaoli; Barnouin-Jha, Olivier; Harmon, John K

2008-07-04

A 3200-kilometers-long profile of Mercury by the Mercury Laser Altimeter on the MESSENGER spacecraft spans approximately 20% of the near-equatorial region of the planet. Topography along the profile is characterized by a 5.2-kilometer dynamic range and 930-meter root-mean-square roughness. At long wavelengths, topography slopes eastward by 0.02 degrees , implying a variation of equatorial shape that is at least partially compensated. Sampled craters on Mercury are shallower than their counterparts on the Moon, at least in part the result of Mercury's higher gravity. Crater floors vary in roughness and slope, implying complex modification over a range of length scales.

Opening a Window on ICME Evolution and GCR Modulation During Propagation in the Innermost Heliosphere

Science.gov (United States)

Winslow, R. M.; Lugaz, N.; Schwadron, N.; Farrugia, C. J.; Guo, J.; Wimmer-Schweingruber, R. F.; Wilson, J. K.; Joyce, C.; Jordan, A.; Lawrence, D. J.

2017-12-01

We use multipoint spacecraft observations to study interplanetary coronal mass ejection (ICME) evolution and subsequent galactic cosmic ray (GCR) modulation during propagation in the inner heliosphere. We illustrate ICME propagation effects through two different case studies. The first ICME was launched from the Sun on 29 December 2011 and was observed in near-perfect longitudinal conjunction at MESSENGER and STEREO A. Despite the close longitudinal alignment, we infer from force-free field modeling that the orientation of the underlying flux rope rotated ˜80o in latitude and ˜65o in longitude. Based on both spacecraft measurements as well as ENLIL model simulations of the steady state solar wind, we find that interactions involving magnetic reconnection with corotating structures in the solar wind dramatically alter the ICME magnetic field. In particular, we observed at STEREO A a highly turbulent region with distinct properties within the flux rope that was not observed at MESSENGER; we attribute this region to interaction between the ICME and a heliospheric plasma sheet/current sheet. This is a concrete example of a sequence of events that can increase the complexity of ICMEs during propagation and should serve as a caution on using very distant observations to predict the geoeffectiveness of large interplanetary transients. Our second case study investigates changes with heliospheric distance in GCR modulation by an ICME event (launched on 12 February 2014) observed in near-conjunction at all four of the inner solar system planets. The ICME caused Forbush decreases (FDs) in the GCR count rates at Mercury (MESSENGER), Earth/Moon (ACE/LRO), and Mars (MSL). At all three locations, the pre-ICME background GCR rate was well-matched, but the depth of the FD of GCR fluxes with similar energy ranges diminished with distance from the Sun. A larger difference in FD size was observed between Mercury and Earth than between Earth and Mars, partly owing to the much larger

Dependence of the amount of open magnetic flux on the direction of the interplanetary magnetic field

International Nuclear Information System (INIS)

Akasofu, S.I.; Ahn, B.H.

1980-01-01

The power generated by the solar wind-magnetosphere dynamo is proportional to the amount of the open magnetic flux phi. It is difficult to use this fact in determining observationally the dependence of phi on the orientation of the interplanetary magnetic field vector. It is shown that, for a simple vacuum superposition of the earth's dipole field and a uniform magnetic field, PHI is very closely proportional to sin(theta/2) for a wide range of the intensity of the uniform field, where theta denotes the polar angle of the interplanetary magnetic field vector in the Y-Z plane of solar-magnetospheric coordinates. (author)

Evidence for a Messenger Function of Cyclic GMP During Phosphodiesterase Induction in Dictyostelium discoideum

NARCIS (Netherlands)

Haastert, Peter J.M. van; Pasveer, Frank J.; Meer, Rob C. van der; Heijden, Paul R. van der; Walsum, Hans van; Konijn, Theo M.

1982-01-01

Chemotactic stimulation of vegetative or aggregative Dictyostelium discoideum cells induced a transient elevation of cyclic GMP levels. The addition of chemoattractants to postvegetative cells by pulsing induced phosphodiesterase activity. The following lines of evidence suggest a messenger function

Suprathermal protons in the interplanetary solar wind

Science.gov (United States)

Goodrich, C. C.; Lazarus, A. J.

1976-01-01

Using the Mariner 5 solar wind plasma and magnetic field data, we present observations of field-aligned suprathermal proton velocity distributions having pronounced high-energy shoulders. These observations, similar to the interpenetrating stream observations of Feldman et al. (1974), are clear evidence that such proton distributions are interplanetary rather than bow shock associated phenomena. Large Alfven speed is found to be a requirement for the occurrence of suprathermal proton distribution; further, we find the proportion of particles in the shoulder to be limited by the magnitude of the Alfven speed. It is suggested that this last result could indicate that the proton thermal anisotropy is limited at times by wave-particle interactions

The topology of intrasector reversals of the interplanetary magnetic field

Science.gov (United States)

Kahler, S. W.; Crooker, N. U.; Gosling, J. T.

1996-11-01

A technique has been developed recently to determine the polarities of interplanetary magnetic fields relative to their origins at the Sun by comparing energetic electron flow directions with local magnetic field directions. Here we use heat flux electrons from the Los Alamos National Laboratory (LANL) plasma detector on the ISEE 3 spacecraft to determine the field polarities. We examine periods within well-defined magnetic sectors when the field directions appear to be reversed from the normal spiral direction of the sector. About half of these intrasector field reversals (IFRs) are cases in which the polarities match those of the surrounding sectors, indicating that those fields have been folded back toward the Sun. The more interesting cases are those with polarity reversals. We find no clear cases of isolated reverse polarity fields, which suggests that islands of reverse polarity in the solar source dipole field probably do not exist. The IFRs with polarity reversals are strongly associated with periods of bidirectional electron flows, suggesting that those fields occur only in conjunction with closed fields. We propose that both those IFRs and the bidirectional flows are signatures of coronal mass ejections (CMEs). In that case, many interplanetary CMEs are larger and more complex than previously thought, consisting of both open and closed field components.

INSTANT MESSENGER (IM) APPLICATION USAGE AT WORKPLACE AND WORKING CULTURE OF A PUBLIC UNIVERSITY SUPPORTING STAFF IN KOTA KINABALU SABAH.

OpenAIRE

Nading, Dorina; Morshidi, Azizan

2016-01-01

Instant Messenger (IM) has becoming a new form of social relations tool in which people interact, dialogue, collaborate and exchange information. Many organizations and companies have adapted their management strategies with the utilization of IM applications, both internally or externally. The popularity of IM in local organizational management in such a way that government agencies, companies, universities, colleges and schools. The use of applications such as wechat, whatsApp messenger...

Planetary science. Low-altitude magnetic field measurements by MESSENGER reveal Mercury's ancient crustal field.

Science.gov (United States)

Johnson, Catherine L; Phillips, Roger J; Purucker, Michael E; Anderson, Brian J; Byrne, Paul K; Denevi, Brett W; Feinberg, Joshua M; Hauck, Steven A; Head, James W; Korth, Haje; James, Peter B; Mazarico, Erwan; Neumann, Gregory A; Philpott, Lydia C; Siegler, Matthew A; Tsyganenko, Nikolai A; Solomon, Sean C

2015-05-22

Magnetized rocks can record the history of the magnetic field of a planet, a key constraint for understanding its evolution. From orbital vector magnetic field measurements of Mercury taken by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft at altitudes below 150 kilometers, we have detected remanent magnetization in Mercury's crust. We infer a lower bound on the average age of magnetization of 3.7 to 3.9 billion years. Our findings indicate that a global magnetic field driven by dynamo processes in the fluid outer core operated early in Mercury's history. Ancient field strengths that range from those similar to Mercury's present dipole field to Earth-like values are consistent with the magnetic field observations and with the low iron content of Mercury's crust inferred from MESSENGER elemental composition data. Copyright © 2015, American Association for the Advancement of Science.

Expected Geochemical and Mineralogical Properties of Meteorites from Mercury: Inferences from Messenger Data

Science.gov (United States)

McCubbin, F. M.; McCoy, T. J.

2016-01-01

Meteorites from the Moon, Mars, and many types of asteroid bodies have been identified among our global inventory of meteorites, however samples of Mercury and Venus have not been identified. The absence of mercurian and venusian meteorites could be attributed to an inability to recognize them in our collections due to a paucity of geochemical information for Venus and Mercury. In the case of mercurian meteorites, this possibility is further supported by dynamical calculations that suggest mercurian meteorites should be present on Earth at a factor of 2-3 less than meteorites from Mars [1]. In the present study, we focus on the putative mineralogy of mercurian meteorites using data obtained from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, which has provided us with our first quantitative constraints on the geochemistry of planet Mercury. We have used the MESSENGER data to compile a list of mineralogical and geochemical characteristics that a meteorite from Mercury is likely to exhibit.

WhatsApp Messenger is useful and reproducible in the assessment of tibial plateau fractures: inter- and intra-observer agreement study.

Science.gov (United States)

Giordano, Vincenzo; Koch, Hilton Augusto; Mendes, Carlos Henrique; Bergamin, André; de Souza, Felipe Serrão; do Amaral, Ney Pecegueiro

2015-02-01

The aim of this study was to evaluate the inter- and intra-observer agreement in the initial diagnosis and classification by means of plain radiographs and CT scans of tibial plateau fractures photographed and sent via WhatsApp Messenger. The increasing popularity of smartphones has driven the development of technology for data transmission and imaging and generated a growing interest in the use of these devices as diagnostic tools. The emergence of WhatsApp Messenger technology, which is available for various platforms used by smartphones, has led to an improvement in the quality and resolution of images sent and received. The images (plain radiographs and CT scans) were obtained from 13 cases of tibial plateau fractures using the iPhone 5 (Apple Inc., Cupertino, CA, USA) and were sent to six observers via the WhatsApp Messenger application. The observers were asked to determine the standard deviation and type of injury, the classification according to the Schatzker and the Luo classifications schemes, and whether the CT scan changed the classification. The six observers independently assessed the images on two separate occasions, 15 days apart. The inter- and intra-observer agreement for both periods of the study ranged from excellent to perfect (0.75WhatsApp Messenger. The authors now propose the systematic use of the application to facilitate faster documentation and obtaining the opinion of an experienced consultant when not on call. Finally, we think the use of the WhatsApp Messenger as an adjuvant tool could be broadened to other clinical centres to assess its viability in other skeletal and non-skeletal trauma situations. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Estimating the Effects of Astronaut Career Ionizing Radiation Dose Limits on Manned Interplanetary Flight Programs

Science.gov (United States)

Koontz, Steven L.; Rojdev, Kristina; Valle, Gerard D.; Zipay, John J.; Atwell, William S.

2013-01-01

The Hybrid Inflatable DSH combined with electric propulsion and high power solar-electric power systems offer a near TRL-now solution to the space radiation crew dose problem that is an inevitable aspect of long term manned interplanetary flight. Spreading program development and launch costs over several years can lead to a spending plan that fits with NASA's current and future budgetary limitations, enabling early manned interplanetary operations with space radiation dose control, in the near future while biomedical research, nuclear electric propulsion and active shielding research and development proceed in parallel. Furthermore, future work should encompass laboratory validation of HZETRN calculations, as previous laboratory investigations have not considered large shielding thicknesses and the calculations presented at these thicknesses are currently performed via extrapolation.

Consideraciones gráficas y lingüísticas del lenguaje cibernético: el chat y el Messenger.

OpenAIRE

Cabedo Nebot, Adrián

2009-01-01

Este trabajo pretende estudiar el comportamiento lingüístico de intercambios comunicativos en plataformas cibernéticas como el chat o el Messenger. Así mismo, el planteamiento inicial es investigar si el lenguaje cibernético constituye un código particular, diferenciado del código del lenguaje habitual. This work tries to study linguistic behavior of communicative exchanges in cybernetic platforms like chat or Messenger. Likewise, the initial approach is to investigate if the cybernetic la...

Calcium in Mercury's Exosphere: Modeling MESSENGER Data

Science.gov (United States)

Burger, Matthew H.; Killen, Rosemary M.; McClintock, William E.; Merkel, Aimee; Vervack, Ronald J.; Sarantos, Menelaos; Sprague, Ann L.

2011-01-01

Mercury is surrounded by a surface-bounded exosphere comprised of atomic species including hydrogen, sodium, potassium, calcium, magnesium, and likely oxygen. Because it is collisionless. the exosphere's composition represents a balance of the active source and loss processes. The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MErcury Surface. Space ENvironment. GEochemistry. and Ranging (MESSENGER) spacecraft has made high spatial-resolution observations of sodium, calcium, and magnesium near Mercury's surface and in the extended, anti-sunward direction. The most striking feature of these data has been the substantial differences in the spatial distribution of each species, Our modeling demonstrates that these differences cannot be due to post-ejection dynamics such as differences in photo-ionization rate and radiation pressure. but instead point to differences in the source mechanisms and regions on the surface from which each is ejected. The observations of calcium have revealed a strong dawn/dusk asymmetry. with the abundance over the dawn hemisphere significantly greater than over the dusk. To understand this asymmetry, we use a Monte Carlo model of Mercury's exosphere that we developed to track the motions of exospheric neutrals under the influence of gravity and radiation pressure. Ca atoms can be ejected directly from the surface or produced in a molecular exosphere (e.g., one consisting of CaO). Particles are removed from the system if they stick to the surface or escape from the model region of interest (within 15 Mercury radii). Photoionization reduces the final weighting given to each particle when simulating the Ca radiance. Preliminary results suggest a high temperature ( I-2x 10(exp 4) K) source of atomic Ca concentrated over the dawn hemisphere. The high temperature is consistent with the dissociation of CaO in a near-surface exosphere with scale height <= 100 km, which imparts 2 eV to the freshly produced Ca atom. This

Are Polar Field Magnetic Flux Concentrations Responsible for Missing Interplanetary Flux?

Science.gov (United States)

Linker, Jon A.; Downs, C.; Mikic, Z.; Riley, P.; Henney, C. J.; Arge, C. N.

2012-05-01

Magnetohydrodynamic (MHD) simulations are now routinely used to produce models of the solar corona and inner heliosphere for specific time periods. These models typically use magnetic maps of the photospheric magnetic field built up over a solar rotation, available from a number of ground-based and space-based solar observatories. The line-of-sight field at the Sun's poles is poorly observed, and the polar fields in these maps are filled with a variety of interpolation/extrapolation techniques. These models have been found to frequently underestimate the interplanetary magnetic flux (Riley et al., 2012, in press, Stevens et al., 2012, in press) near the minimum part of the cycle unless mitigating correction factors are applied. Hinode SOT observations indicate that strong concentrations of magnetic flux may be present at the poles (Tsuneta et al. 2008). The ADAPT flux evolution model (Arge et al. 2010) also predicts the appearance of such concentrations. In this paper, we explore the possibility that these flux concentrations may account for a significant amount of magnetic flux and alleviate discrepancies in interplanetary magnetic flux predictions. Research supported by AFOSR, NASA, and NSF.

Type II solar radio bursts, interplanetary shocks, and energetic particle events

International Nuclear Information System (INIS)

Cane, H.V.; Stone, R.G.

1984-01-01

Using the ISEE 3 radio astronomy experiment data we have identified 37 interplanetary type II bursts in the period 1978 September to 1981 December. We lists these events and the associated phenomena. The events are preceded by intense, soft X-ray events with long decay times and type II or type IV bursts, or both, at meter wavelengths. The meter wavelength type II bursts are usually intense and exhibit herringbone structure. The extension of the herringbone structure into the kilometer wavelength range appears as a fast drift radio feature which we refer to as a shock associated radio event. The shock associated event is an important diagnostic for the presence of a strong shock and particle acceleration. The majority of the interplanetary type II bursts are associated with energetic particle events. Our results support other studies which indicate that energetic soalr particles detected at 1 A.U. are generatd by shock acceleration. From a preliminary analysis of the available data there appears to be a high correlation with white light coronal transients. The transients are fast: i.e., velocities greater than 500 km s -1

Convection in the polar ionosphere and the state of the interplanetary medium

Science.gov (United States)

Uvarov, V. M.; Barashkov, P. D.

A model of the continuous distribution of electric fields (E) controlled by parameters of the interplanetary medium has been developed which reproduces all the empirically known types of E distributions. This model is used to calculate the corresponding types of plasma convection in the polar ionosphere, represented by two-, three-, and four-vortex structures.

Mid-Infrared Spectrum of the Zodiacal Emission: Detection of Crystalline Silicates in Interplanetary Dust

Science.gov (United States)

Ootsubo, T.; Onaka, T.; Yamamura, I.; Ishihara, D.; Tanabe, T.; Roellig, T. L.

2003-01-01

Within a few astronomical units of the Sun the solar system is filled with interplanetary dust, which is believed to be dust of cometary and asteroidal origin. Spectroscopic observations of the zodiacal emission with moderate resolution provide key information on the composition and size distribution of the dust in the interplanetary space. They can be compared directly to laboratory measurements of candidate materials, meteorites, and dust particles collected in the stratosphere. Recently mid-infrared spectroscopic observations of the zodiacal emission have been made by two instruments on board the Infrared Space Observatory; the camera (ISOCAM) and the spectrophotometer (ISOPHOT-S). A broad excess emission feature in the 9-11 micron range is reported in the ISOCAM spectrum, whereas the ISOPHOT-S spectra in 6-12 microns can be well fitted by a blackbody radiation without spectral features.

The VISTA spacecraft: Advantages of ICF [Inertial Confinement Fusion] for interplanetary fusion propulsion applications

International Nuclear Information System (INIS)

Orth, C.D.; Klein, G.; Sercel, J.; Hoffman, N.; Murray, K.; Chang-Diaz, F.

1987-01-01

Inertial Confinement Fusion (ICF) is an attractive engine power source for interplanetary manned spacecraft, especially for near-term missions requiring minimum flight duration, because ICF has inherent high power-to-mass ratios and high specific impulses. We have developed a new vehicle concept called VISTA that uses ICF and is capable of round-trip manned missions to Mars in 100 days using A.D. 2020 technology. We describe VISTA's engine operation, discuss associated plasma issues, and describe the advantages of DT fuel for near-term applications. Although ICF is potentially superior to non-fusion technologies for near-term interplanetary transport, the performance capabilities of VISTA cannot be meaningfully compared with those of magnetic-fusion systems because of the lack of a comparable study of the magnetic-fusion systems. We urge that such a study be conducted

The MESSENGER mission to Mercury: scientific objectives and implementation

Science.gov (United States)

Solomon, Sean C.; McNutt, Ralph L.; Gold, Robert E.; Acuña, Mario H.; Baker, Daniel N.; Boynton, William V.; Chapman, Clark R.; Cheng, Andrew F.; Gloeckler, George; Head, James W., III; Krimigis, Stamatios M.; McClintock, William E.; Murchie, Scott L.; Peale, Stanton J.; Phillips, Roger J.; Robinson, Mark S.; Slavin, James A.; Smith, David E.; Strom, Robert G.; Trombka, Jacob I.; Zuber, Maria T.

2001-12-01

Mercury holds answers to several critical questions regarding the formation and evolution of the terrestrial planets. These questions include the origin of Mercury's anomalously high ratio of metal to silicate and its implications for planetary accretion processes, the nature of Mercury's geological evolution and interior cooling history, the mechanism of global magnetic field generation, the state of Mercury's core, and the processes controlling volatile species in Mercury's polar deposits, exosphere, and magnetosphere. The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission has been designed to fly by and orbit Mercury to address all of these key questions. After launch by a Delta 2925H-9.5, two flybys of Venus, and two flybys of Mercury, orbit insertion is accomplished at the third Mercury encounter. The instrument payload includes a dual imaging system for wide and narrow fields-of-view, monochrome and color imaging, and stereo; X-ray and combined gamma-ray and neutron spectrometers for surface chemical mapping; a magnetometer; a laser altimeter; a combined ultraviolet-visible and visible-near-infrared spectrometer to survey both exospheric species and surface mineralogy; and an energetic particle and plasma spectrometer to sample charged species in the magnetosphere. During the flybys of Mercury, regions unexplored by Mariner 10 will be seen for the first time, and new data will be gathered on Mercury's exosphere, magnetosphere, and surface composition. During the orbital phase of the mission, one Earth year in duration, MESSENGER will complete global mapping and the detailed characterization of the exosphere, magnetosphere, surface, and interior.

Studies of Solar Flare and Interplanetary Particle Acceleration and Coordination of Ground-Based Solar Observations in Support of US and International Space Missions

Science.gov (United States)

Kiplinger, Alan L.

1998-01-01

A primary focus has been to conduct studies of particular types of hard X-ray evolution in solar flares and their associations with high energy interplanetary protons observed near Earth. Previously, two large investigations were conducted that revealed strong associations between episodes of progressive spectral hardening seen in solar events and interplanetary proton events (Kiplinger, 1995). An algorithm was developed for predicting interplanetary protons that is more accurate than those currently in use when hard X-ray spectra are available. The basic research on a third study of the remaining independent subset of Hard X-ray Burst Spectrometer (HXRBS) events randomly not selected by the original studies was completed. This third study involves independent analyses of the data by two analysts. The results echo the success of the earlier studies. Of 405 flares analyzed, 12 events were predicted to have associated interplanetary protons at the Space Environment Service Center (SESC) level. Of these, five events appear to be directly associated with SESC proton events, six other events had lower level associated proton events, and there was only one false alarm with no protons. Another study by Garcia and Kiplinger (1995) established that progressively hardening hard X-ray flares associated with interplanetary proton events are intrinsically cooler and not extremely intense in soft X-rays unless a "contaminating" large impulsive flare accompanies the hardening flare.

Kuiper Belt Dust Grains as a Source of Interplanetary Dust Particles

Science.gov (United States)

Liou, Jer-Chyi; Zook, Herbert A.; Dermott, Stanley F.

1996-01-01

The recent discovery of the so-called Kuiper belt objects has prompted the idea that these objects produce dust grains that may contribute significantly to the interplanetary dust population. In this paper, the orbital evolution of dust grains, of diameters 1 to 9 microns, that originate in the region of the Kuiper belt is studied by means of direct numerical integration. Gravitational forces of the Sun and planets, solar radiation pressure, as well as Poynting-Robertson drag and solar wind drag are included. The interactions between charged dust grains and solar magnetic field are not considered in the model. Because of the effects of drag forces, small dust grains will spiral toward the Sun once they are released from their large parent bodies. This motion leads dust grains to pass by planets as well as encounter numerous mean motion resonances associated with planets. Our results show that about 80% of the Kuiper belt grains are ejected from the Solar System by the giant planets, while the remaining 20% of the grains evolve all the way to the Sun. Surprisingly, the latter dust grains have small orbital eccentricities and inclinations when they cross the orbit of the Earth. This makes them behave more like asteroidal than cometary-type dust particles. This also enhances their chances of being captured by the Earth and makes them a possible source of the collected interplanetary dust particles; in particular, they represent a possible source that brings primitive/organic materials from the outer Solar System to the Earth. When collisions with interstellar dust grains are considered, however, Kuiper belt dust grains around 9 microns appear likely to be collisionally shattered before they can evolve toward the inner part of the Solar System. The collision destruction can be applied to Kuiper belt grains up to about 50 microns. Therefore, Kuiper belt dust grains within this range may not be a significant part of the interplanetary dust complex in the inner Solar

Dayside auroras in relation to the interplanetary magnetic field

International Nuclear Information System (INIS)

Sandholt, P.E.; Egeland, A.; Lybekk, B.; Deehr, C.S.

1986-01-01

Dynamics of dayside auroras, including cusp emissions, and their relation to the interplanetary magnetic field (IMF) have been investigated by optical ground-based observations from Svalbard, Norway, and IMF data from various satellites. Combined with the Svalbard program, simultaneous night-side observations from Alaska provide information on the large-scale behaviour of the auroral oval. Drift characteristics, spatial scale, time of duration and repetition frequency of auroral structures on the day-side, occuring at the time of large-scale oval expansions (IMF B z z positive and negative values

The space environment of Mercury at the times of the second and third MESSENGER flybys

Czech Academy of Sciences Publication Activity Database

Baker, D. N.; Odstrčil, D.; Anderson, B.J.; Arge, C. N.; Benna, M.; Gloeckler, G.; Korth, H.; Mayer, L. R.; Raines, J.M.; Schriver, D.; Slavin, J.A.; Solomon, S.C.; Trávníček, Pavel M.; Zurbuchen, T.H.

2011-01-01

Roč. 59, č. 15 (2011), s. 2066-2074 ISSN 0032-0633 Institutional support: RVO:67985815 Keywords : Mercury * solar wind * interplanetary magnetic field Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 2.224, year: 2011

Possible mechanism of the interplanetary medium effect on the diurnal rotation rate of the Earth

International Nuclear Information System (INIS)

Krymskij, P.F.

1993-01-01

Mechanism is proposed for effect of the solar wind and interplanetary magnetic field on the Earth rotation. In the mechanism base is Hall current generation in the plasma layer of the magnetosphere tail

Turbulence in the solar atmosphere and in the interplanetary plasma

International Nuclear Information System (INIS)

Chashei, I.V.; Shishov, V.I.

1984-01-01

Analysis of the basic properties of the turbulence in the solar chromosphere, corona, and supercorona (the plasma acceleration zone) indicates that the energy of acoustic disturbances generated at the photospheric level will be conveyed outward into the interplanetary plasma jointly by nonlinear wave interactions and wave propagation effects. Above the chromosphere, damping will be strongest at heights Rroughly-equal0.4 R/sub sun/ for acoustic-type waves and at Rroughly-equalR/sub sun/ for Alfven waves

Simulating multi-spacecraft Heliospheric Imager observations for tomographic reconstruction of interplanetary CMEs

Science.gov (United States)

Barnes, D.

2017-12-01

The multiple, spatially separated vantage points afforded by the STEREO and SOHO missions provide physicists with a means to infer the three-dimensional structure of the solar corona via tomographic imaging. The reconstruction process combines these multiple projections of the optically thin plasma to constrain its three-dimensional density structure and has been successfully applied to the low corona using the STEREO and SOHO coronagraphs. However, the technique is also possible at larger, inter-planetary distances using wide-angle imagers, such as the STEREO Heliospheric Imagers (HIs), to observe faint solar wind plasma and Coronal Mass Ejections (CMEs). Limited small-scale structure may be inferred from only three, or fewer, viewpoints and the work presented here is done so with the aim of establishing techniques for observing CMEs with upcoming and future HI-like technology. We use simulated solar wind densities to compute realistic white-light HI observations, with which we explore the requirements of such instruments for determining solar wind plasma density structure via tomography. We exploit this information to investigate the optimal orbital characteristics, such as spacecraft number, separation, inclination and eccentricity, necessary to perform the technique with HIs. Further to this we argue that tomography may be greatly enhanced by means of improved instrumentation; specifically, the use of wide-angle imagers capable of measuring polarised light. This work has obvious space weather applications, serving as a demonstration for potential future missions (such as at L1 and L5) and will prove timely in fully exploiting the science return from the upcoming Solar Orbiter and Parker Solar Probe missions.

Nonlinear generation of the fundamental radiation of interplanetary type III radio bursts

International Nuclear Information System (INIS)

Chian, A.C.L.; Alves, M.V.

1988-01-01

A new generation mechanism of interplanetary type III radio bursts at the fundamental electron plasma frequency is discussed. It is shown that the electromagnetic oscillating two-stream instability, driven by two oppositely propagating Langmuir waves, can account for the experimental observations. In particular, the major difficulties encountered by the previously considered electromagnetic decay instability are removed. 19 references

Correlation Between Monthly Cumulative Auroral Electrojet Indices, DST Index and Interplanetary Electric Field During Magnetic Storms

Directory of Open Access Journals (Sweden)

Yoon-Kyung Park

2005-12-01

Full Text Available Magnetospheric substorms occur frequently during magnetic storms, suggesting that the two phenomena are closely associated. We can investigate the relation between magnetospheric substorms and magnetic storms by examining the correlation between AE and Dst indices. For this purpose, we calculated the monthly cumulative AU, |AL| and |Dst| indices. The correlation coefficient between the monthly cumulative |AL| and |Dst| index is found to be 0.60, while that between monthly cumulative AU and |Dst| index is 0.28. This result indicates that substorms seem to contribute to the development of magnetic storms. On the other hand, it has been reported that the interplanetary electric field associated with southward IMF intensifies the magnetospheric convection, which injects charged particles into the inner magnetosphere, thus developing the ring current. To evaluate the contribution of the interplanetary electric field to the development of the storm time ring current belt, we compared the monthly cumulative interplanetary electric field and the monthly cumulative Dst index. The correlation coefficient between the two cumulative indices is 0.83 for southward IMF and 0.39 for northward IMF. It indicates that magnetospheric convection induced by southward IMF is also important in developing magnetic storms. Therefore, both magnetospheric substorm and enhanced magnetospheric convection seem to contribute to the buildup of magnetic storm.

Identification of messenger RNA of fetoplacental source in maternal plasma of women with normal pregnancies and pregnancies with intrauterine growth restriction.

Science.gov (United States)

Ayala Ramírez, Paola; García Robles, Reggie; Rojas, Juan Diego; Bermúdez, Martha; Bernal, Jaime

2012-07-01

to quantify placenta-specific RNA in plasma of women carrying foetuses with intrauterine growth restriction and pregnant women with normal pregnancies. 8 pregnant women with foetuses with intrauterine growth restriction were studied as well as 18 women with uncomplicated pregnancies in the third pregnancy trimester. Total free RNA was quantified in maternal plasma by spectrophotometry and the gene expression of hPL (Human Placental Lactogen) at the messenger RNA level through technical Real Time-Chain Reaction Polymerase. plasma RNA of fetoplacental origin was successfully detected in 100% of pregnant women. There were no statistically significant differences between the values of total RNA extracted from plasma (p= 0.5975) nor in the messenger RNA expression of hPL gene (p= 0.5785) between cases and controls. messenger RNA of fetoplacental origin can be detected in maternal plasma during pregnancy.

A rapid, ratiometric, enzyme-free, and sensitive single-step miRNA detection using three-way junction based FRET probes

Science.gov (United States)

Luo, Qingying; Liu, Lin; Yang, Cai; Yuan, Jing; Feng, Hongtao; Chen, Yan; Zhao, Peng; Yu, Zhiqiang; Jin, Zongwen

2018-03-01

MicroRNAs (miRNAs) are single stranded endogenous molecules composed of only 18-24 nucleotides which are critical for gene expression regulating the translation of messenger RNAs. Conventional methods based on enzyme-assisted nucleic acid amplification techniques have many problems, such as easy contamination, high cost, susceptibility to false amplification, and tendency to have sequence mismatches. Here we report a rapid, ratiometric, enzyme-free, sensitive, and highly selective single-step miRNA detection using three-way junction assembled (or self-assembled) FRET probes. The developed strategy can be operated within the linear range from subnanomolar to hundred nanomolar concentrations of miRNAs. In comparison with the traditional approaches, our method showed high sensitivity for the miRNA detection and extreme selectivity for the efficient discrimination of single-base mismatches. The results reveal that the strategy paved a new avenue for the design of novel highly specific probes applicable in diagnostics and potentially in microscopic imaging of miRNAs in real biological environments.

Pengaruh Social Media Marketing melalui Blackberry Messenger terhadap Minat Beli Konsumen di PT Agung Automall (Agung Toyota) Harapan Raya Pekanbaru

OpenAIRE

Lubis, Evawani Elysa; Pratama, Lian

2016-01-01

The rise of social media is the new media can be used as marketing at once to do consumer interaction, called social media marketing. One of the social media marketing which is now popular among business people, IE blackberry messenger. Through this application can send a message text, sound, and images for free about their business or place information and promotions offered from their products so that it formed an interest to buy from someone, with the blackberry messenger messages or infor...

Orbital and angular motion construction for low thrust interplanetary flight

Science.gov (United States)

Yelnikov, R. V.; Mashtakov, Y. V.; Ovchinnikov, M. Yu.; Tkachev, S. S.

2016-11-01

Low thrust interplanetary flight is considered. Firstly, the fuel-optimal control is found. Then the angular motion is synthesized. This motion provides the thruster tracking of the required by optimal control direction. And, finally, reaction wheel control law for tracking this angular motion is proposed and implemented. The numerical example is given and total operation time for thrusters is found. Disturbances from solar pressure, thrust eccentricity, inaccuracy of reaction wheels installation and errors of inertia tensor are taken into account.

Design of a synthetic luminescent probe from a biomolecule binding domain: selective detection of AU-rich mRNA sequences.

Science.gov (United States)

Raibaut, Laurent; Vasseur, William; Shimberg, Geoffrey D; Saint-Pierre, Christine; Ravanat, Jean-Luc; Michel, Sarah L J; Sénèque, Olivier

2017-02-01

We report the design of a luminescent sensor based upon the zinc finger (ZF) protein TIS11d, that allows for the selective time-resolved detection of the UUAUUUAUU sequence of the 3'-untranslated region of messenger RNA. This sensor is composed of the tandem ZF RNA binding domain of TIS11d functionalized with a luminescent Tb 3+ complex on one of the ZFs and a sensitizing antenna on the other. This work provides the proof of principle that an RNA binding protein can be re-engineered as an RNA sensor and, more generally, that tunable synthetic luminescent probes for biomolecules can be obtained by modifying biomolecule-binding domains.

Relation of the Dsub(st) index to the azimuth component of the interplanetary magnetic field vector during separate storms

International Nuclear Information System (INIS)

Kovalevskij, I.V.; Levitin, A.E.; Fedoseeva, M.K.

1984-01-01

A relation between the index Dsub(st) and azimuthal component Bsub(y) of interplanetary magnetic field (IMF) vector during several magnetic storms with Dsub(st) > 100nT is discussed. It is established that the relation between Dsub(st) index and Bsub(y) and Esub(z) component of electric interplanetary field (EIF) is closed than the relation between Dsub(st) and Bsub(z) component of IMF and Esub(y) component of EIF. Correlation coefficients of Dsub(st) and Bsub(y) and Esub(z) differ but slightly from each other

Pathophysiological implications of the chemical messengers; Implicaciones fisiopatologicas de los mensajeros quimicos

Energy Technology Data Exchange (ETDEWEB)

Blazquez Fernandez, E.

2009-07-01

To maintain a physical organization and a different composition of its surroundings environment, living beings use a great part of the energy that they produce. Vital processes require an elevated number of reactions which are regulated and integrated by chemical messengers. They use autocrine, paracrine, endocrine and synaptic signals through receptors of cell surface, nuclear or associated with ionic channels, enzymes, trim eric G proteins and to intracellular kinases. Through these mechanisms pheromones play an important role in the relationships between different individuals, and hormones are able to regulate the integrative functions of our organism. In the nervous system, neurotransmitters, neuromodulators, sensors and receptors between other messengers, play functions of great relevance, while growth factors stimulate cell proliferation and cytokines have many effects but the most important is the ones related with the control of the immflamatory process. Alterations of these messengers permit us a better understanding of the diseases and possibly of its treatments in a near future. Modifications of the expression of genes from the nuclear and mitochondrial genomes are responsible of monogenic, polygenic and mitochondrial diseases, while alterations in the activities of dopamine and serotonin neurotransmitters are related with schizophrenia, Parkinson disease and depression, respectively. Other example is the hyperthyroidism of the Graves-Bassedow disease due to the competitive interference of the LATS immunoglobulin with TSH at the level of the follicular cells producing thyroid hormones Twenty five years ago in the reviews on the mechanisms of insulin action, there was presentations in which the insulin receptor was located in the plasma membrane of the target cells while in the cytoplasm only a big interrogative was observed, that at present is replaced by chemical mediators cascades responsible of the multiple effects of insulin. This finding is similar

Solar sources of interplanetary southward B/sub z/ events responsible for major magnetic storms (1978--1979)

International Nuclear Information System (INIS)

Tang, F.; Tsurutani, B.T.; Gonzalez, W.D.; Akasofu, S.I.; Smith, E.J.

1989-01-01

Tsurutani et al. [1988] analyzed the 10 intense interplanetary southward B/sub z/ events that led to major magnetic storms (Dst 3.0) are associated with prominence eruptions. For three of the five southward B/sub z/ events in which the driver gases are the causes of the intense southward field leading to magnetic storms, the photospheric fields of the solar sources have no dominant southward component, indicating the driver gas fields do not always result from a simple outward convection of solar magnetic fields. Finally we compare the solar events and their resulting interplanetary shocks and find that the standard solar parameters do not correlate with the strengths of the resulting shocks at 1 AU. The implications are discussed. copyright American Geophysical Union 1989

Mobile Immersion: An Experiment Using Mobile Instant Messenger to Support Second-Language Learning

Science.gov (United States)

Lai, Arthur

2016-01-01

Immersion has been an acclaimed approach for second-language acquisition, but is not available to most students. The idea of this study was to create a mobile immersion environment on a smartphone using a mobile instant messenger, WhatsApp™. Forty-five Form-1 (7th grade) students divided into the Mobile Group and Control Group participated in a…

An Alternative Method for Identifying Interplanetary Magnetic Cloud Regions

Energy Technology Data Exchange (ETDEWEB)

Ojeda-Gonzalez, A.; Prestes, A.; Klausner, V. [Laboratory of Physics and Astronomy, IP and D/Universidade do Vale do Paraíba—UNIVAP, São José dos Campos, SP (Brazil); Mendes, O. [Division of Space Geophysics, National Institute for Space Research, São José dos Campos, SP (Brazil); Calzadilla, A. [Department of Space Geophysics, Institute of Geophysics and Astronomy, Havana (Cuba); Domingues, M. O., E-mail: ojeda.gonzalez.a@gmail.com [Associate Laboratory of Applied Computing and Mathematics, National Institute for Space Research, São José dos Campos, SP (Brazil)

2017-03-10

Spatio-temporal entropy (STE) analysis is used as an alternative mathematical tool to identify possible magnetic cloud (MC) candidates. We analyze Interplanetary Magnetic Field (IMF) data using a time interval of only 10 days. We select a convenient data interval of 2500 records moving forward by 200 record steps until the end of the time series. For every data segment, the STE is calculated at each step. During an MC event, the STE reaches values close to zero. This extremely low value of STE is due to MC structure features. However, not all of the magnetic components in MCs have STE values close to zero at the same time. For this reason, we create a standardization index (the so-called Interplanetary Entropy, IE, index). This index is a worthwhile effort to develop new tools to help diagnose ICME structures. The IE was calculated using a time window of one year (1999), and it has a success rate of 70% over other identifiers of MCs. The unsuccessful cases (30%) are caused by small and weak MCs. The results show that the IE methodology identified 9 of 13 MCs, and emitted nine false alarm cases. In 1999, a total of 788 windows of 2500 values existed, meaning that the percentage of false alarms was 1.14%, which can be considered a good result. In addition, four time windows, each of 10 days, are studied, where the IE method was effective in finding MC candidates. As a novel result, two new MCs are identified in these time windows.

Microcharacterization of interplanetary dust collected in the earth's stratosphere

International Nuclear Information System (INIS)

Fraundorf, P.B.

1980-01-01

This thesis involved an examination of the internal structure of thirteen 10 μm aggregates using selected techniques from the field now known as analytical electron microscopy. The aggregates were collected in the earth's stratosphere at 20 km altitude by impactors mounted on NASA U-2 aircraft. Eleven of them exhibited relative major element abundances similar to those found in chondritic meteorities. For this and other reasons, these eleven particles are believed to represent relatively-unaltered interplanetary dust. Interplanetary dust is thought to be of cometary origin, and comets in turn provide the most promising reservoir for unaltered samples of materials present during the collapse of the solar nebula. This thesis shows that the chondritic aggregates probably contain important information on a wide range of processes in the early solar system. In the course of this study, significant developments were necessary in the techniques of analysis for: (i) selected area electron diffraction (SAED) data; (ii) energy dispersive x-ray spectra; and (iii) spatial heterogeneity in geological materials. These developments include a method for analysing single crystal SAED patterns using spherical geometry. The method makes possible much more efficient use of diffraction data taken with a goniometer specimen stage. It allows major portions of the analysis to be done by a microprocessor, and it has potential for a wide range of on-line applications. Also, a comprehensive approach to the study of point-to-point heterogeneity in geological materials was developed. Some statistical, comparative, petrographic, and physical applications are described in the thesis

Equatorial storm sudden commencements and interplanetary magnetic field

International Nuclear Information System (INIS)

Rastogi, R.G.

1980-01-01

A comparison is made of the signatures of interplanetary (IP) shocks in the B and theta plots of interplanetary magnetic field (IMF) data of satellites Explorer 33, 34 and 35 and in the H magnetograms at ground observatories within the equatorial electrojet belt, Huancayo, Addis Ababa and Trivandrum associated with major storm sudden commencements during 1967-70. The IP shocks showing sudden increase of the scalar value of IMF, i.e. B without any change of the latitude theta or with the southward turning of theta, were followed by a purely positive sudden increase of H, at any of the magnetic observatories, either on the dayside or the nightside of the earth. The IP shocks identified by a sudden increase of B and with the northward turning of the latitude theta (positive ΔBsub(z)) were associated with purely positive sudden commencement (SC) at the observatories in the nightside, but at the equatorial observatories in the dayside of the earth the signature of the shock was a SC in H with a preliminary negative impulse followed by the main positive excursion (SC-+). It is suggested that the SCs in H at low latitudes are composed of two effects, viz. (i) one due to hydromagnetic pressure on the magnetosphere by the solar plasma and (ii) the other due to the induced electric field associated with the solar wind velocity, V and the Z-component of the IP magnetic field (E = - V x Bsub(z)). The effect of magnetosphere electric field is faster than the effect due to the compression of the magnetosphere by the impinging solar plasma. The negative impulse of SC-+ at low latitude is seen at stations close to the dip equator and only during daytime due to the existence of high ionospheric conductivities in the equatorial electrojet region. (author)

Heliocentric distance dependence of the interplanetary magnetic field

International Nuclear Information System (INIS)

Behannon, K.W.

1978-01-01

Recent and ongoing planetary missions have provided and are continuing to provide extensive observations of the variations of the interplanetary magnetic field (IMF) both in time and with heliocentric distance from the sun. Large time variations in both the IMF and its fluctuations are observed. These are produced predominantly by dynamical processes in the interplanetary medium associated with stream interactions. Magnetic field variations near the sun are propagated to greater heliocentric distances, a process also contributing to the observed variability of the IMF. Temporal variations on a time scale comparable to or less than the corotation period complicate attempts to deduce radial gradients of the field and its fluctuations from the various observations. However, recent measurements inward to 0.46 AU and outward to 5 AU suggest that the radial component of the field on average decreases approximately as r -2 , as was predicted by Parker, while the azimuthal component decreases more rapidly than the r -1 dependence predicted by simple theory. Three sets of observations are consistent with r/sup -1.3/ dependence for vertical-barB/sub phi/vertical-bar. The temporal variability of solar wind speed is most likely the predominant contributor to this latter observational result. The long-term average azimuthal component radial gradient is probably consistent with the Parker r -1 dependence when solar wind speed variations are taken into account. The observations of the normal component magnitude vertical-barB/sub theta/vertical-bar are roughly consistent with a heliocentric distance dependence of r/sup -1.4/. The observed radial distance dependence of the total magnitude of the IMF is well described by the Parker formulation. There is observational evidence that amplitudes of fluctuations of the vector field with periods less than 1 day vary with heliocentric distance as approximately r/sup -3/2/, in agreement with theoretical models by Whang and Hollweg

Pioneer Venus and near-earth observations of interplanetary shocks

International Nuclear Information System (INIS)

Mihalov, J.D.; Russell, C.T.; Knudsen, W.C.; Scarf, F.L.

1987-01-01

Twenty-three transient interplanetary shocks observed near earth during 1978-1982, and mostly reported in the literature, have also been identified at the Pioneer Venus Orbiter spacecraft. There seems to be a fairly consistent trend for lower shock speeds, farther from the sun. Shock normals obtained using the Pioneer Venus data correspond well with published values from near earth. By referring to the portion of the Pioneer Venus plasma data used here from locations at longitudes within 37 degree of earth, it is found that shocks are weaker at earth, compared with closer to the sun

Numerical Simulation on a Possible Formation Mechanism of Interplanetary Magnetic Cloud Boundaries

Science.gov (United States)

Fan, Quan-Lin; Wei, Feng-Si; Feng, Xue-Shang

2003-08-01

The formation mechanism of the interplanetary magnetic cloud (MC) boundaries is numerically investigated by simulating the interactions between an MC of some initial momentum and a local interplanetary current sheet. The compressible 2.5D MHD equations are solved. Results show that the magnetic reconnection process is a possible formation mechanism when an MC interacts with a surrounding current sheet. A number of interesting features are found. For instance, the front boundary of the MCs is a magnetic reconnection boundary that could be caused by a driven reconnection ahead of the cloud, and the tail boundary might be caused by the driving of the entrained flow as a result of the Bernoulli principle. Analysis of the magnetic field and plasma data demonstrates that at these two boundaries appear large value of the plasma parameter β, clear increase of plasma temperature and density, distinct decrease of magnetic magnitude, and a transition of magnetic field direction of about 180 degrees. The outcome of the present simulation agrees qualitatively with the observational results on MC boundary inferred from IMP-8, etc. The project supported by National Natural Science Foundation of China under Grant Nos. 40104006, 49925412, and 49990450

Time Domain Astronomy with Fermi GBM in the Multi-messenger Era

Science.gov (United States)

Wilson-Hodge, Colleen A.; Fermi GBM team, GBM-LIGO team

2018-01-01

As the Multi-Messenger era begins with detections of gravitational waves with LIGO/Virgo and neutrinos with IceCube, the Fermi Gamma-ray Burst Monitor (GBM) provides context observations of gamma-ray transients between 8 keV and 40 MeV. Fermi GBM has a wide field of view, high uptime, and both in-orbit triggering and high time resolution continuous data enabling offline searches for weaker transients. GBM detects numerous gamma-ray bursts (GRBs), soft gamma-ray repeaters, X-ray bursters, solar flares and terrestrial gamma-ray flashes. Longer timescale transients, predominantly in our galaxy so far, are detected using the Earth occultation technique and epoch-folding for periodic sources. The GBM team has developed two ground-based searches to enhance detections of faint transients, especially short GRBs. The targeted search uses the time and location of an event detected with another instrument to coherently search the GBM data, increasing the sensitivity to a transient. The untargeted search agnostically searches the GBM data for all directions and times to find weaker transients. This search finds about 80 short GRBs per year, adding to the 40 per year triggered on-orbit. With its large field of view, high duty cycle and increasingly sophisticated detection methods, Fermi GBM is expected to have a major role in the Multi-Messenger era.

Relations between turbulent regions of interplanetary magnetic field and Jovian decametric radio wave emissions from the main source

International Nuclear Information System (INIS)

Oya, H.; Morioka, A.

1981-01-01

Jovian decametric radio wave emissions that were observed at Goddard Space Flight Center, U.S.A. for a period from 1 October to 31 December, 1974 and data obtained at Mt. Zao observatory, Tohoku University, Japan, for a period from 14 July to 6 December, 1975 have been used to investigate the relationship of the occurrence of the Jovian decametric radio waves (JDW), from the main source, to the geomagnetic disturbance index, ΣKAPPA sub(rho). The dynamic cross-correlation between JDW and ΣKAPPAsubrho indicates an enhanced correlation for certain values of delay time. The delay time is consistent with predicted values based on a model of rotating turbulent regions in interplanetary space associated with two sector boundaries of the interplanetary magnetic field, i.e. the rotating sector boundaries of the interplanetary magnetic field first encounter the Earth's magnetosphere producing the geomagnetic field disturbances, and after a certain period, they encounter the Jovian magnetosphere. There are also cases where the order of the encounter is opposite, i.e. the sector boundaries encounter first Jovian magnetosphere and encounter the Earth's magnetosphere after a certain period. (author)

Laser-fusion rocket for interplanetary propulsion

International Nuclear Information System (INIS)

Hyde, R.A.

1983-01-01

A rocket powered by fusion microexplosions is well suited for quick interplanetary travel. Fusion pellets are sequentially injected into a magnetic thrust chamber. There, focused energy from a fusion Driver is used to implode and ignite them. Upon exploding, the plasma debris expands into the surrounding magnetic field and is redirected by it, producing thrust. This paper discusses the desired features and operation of the fusion pellet, its Driver, and magnetic thrust chamber. A rocket design is presented which uses slightly tritium-enriched deuterium as the fusion fuel, a high temperature KrF laser as the Driver, and a thrust chamber consisting of a single superconducting current loop protected from the pellet by a radiation shield. This rocket can be operated with a power-to-mass ratio of 110 W gm -1 , which permits missions ranging from occasional 9 day VIP service to Mars, to routine 1 year, 1500 ton, Plutonian cargo runs

Particle acceleration in the interplanetary space

International Nuclear Information System (INIS)

Tverskoj, B.A.

1983-01-01

A review on the problem of particle acceleration in the interplanetary space is given. The main lationship attention is paid to the problem of the re/ between the impact- and turbulent acceleration when an undisturbed magnetic field forms not too small angle THETA > 10 deg with the shock wave front. The following conclusions are drawn. Particle acceleration at the shock wave front is manifested in the explicit form, if the shock wave propagates along a homogeneous (in the 11 cm range) solar wind. The criterion of such an acceleration is the exponential distribution function F approximately vsup(-ν) (v is the particle velocity and ν is the accelerated particle spectrum index) in the low energy range and the conservation of this function at considerable distances behind the front. The presence of an additional turbulent acceleration behind the front is manifested in decreasing ν down to approximately 3.5 in the low energy range and in the spectrum evolution behind the front

Sunward-propagating Solar Energetic Electrons inside Multiple Interplanetary Flux Ropes

Energy Technology Data Exchange (ETDEWEB)

Gómez-Herrero, Raúl; Hidalgo, Miguel A.; Carcaboso, Fernando; Blanco, Juan J. [Dpto. de Física y Matemáticas, Universidad de Alcalá, E-28871 Alcalá de Henares, Madrid (Spain); Dresing, Nina; Klassen, Andreas; Heber, Bernd [Institut für Experimentelle und Angewandte Physik, University of Kiel, D-24118, Kiel (Germany); Temmer, Manuela; Veronig, Astrid [Institute of Physics/Kanzelhöhe Observatory, University of Graz, A-8010 Graz (Austria); Bučík, Radoslav [Institut für Astrophysik, Georg-August-Universität Göttingen, D-37077, Göttingen (Germany); Lario, David, E-mail: raul.gomezh@uah.es [The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723 (United States)

2017-05-10

On 2013 December 2 and 3, the SEPT and STE instruments on board STEREO-A observed two solar energetic electron events with unusual sunward-directed fluxes. Both events occurred during a time interval showing typical signatures of interplanetary coronal mass ejections (ICMEs). The electron timing and anisotropies, combined with extreme-ultraviolet solar imaging and radio wave spectral observations, are used to confirm the solar origin and the injection times of the energetic electrons. The solar source of the ICME is investigated using remote-sensing observations and a three-dimensional reconstruction technique. In situ plasma and magnetic field data combined with energetic electron observations and a flux-rope model are used to determine the ICME magnetic topology and the interplanetary electron propagation path from the Sun to 1 au. Two consecutive flux ropes crossed the STEREO-A location and each electron event occurred inside a different flux rope. In both cases, the electrons traveled from the solar source to 1 au along the longest legs of the flux ropes still connected to the Sun. During the December 2 event, energetic electrons propagated along the magnetic field, while during the December 3 event they were propagating against the field. As found by previous studies, the energetic electron propagation times are consistent with a low number of field line rotations N < 5 of the flux rope between the Sun and 1 au. The flux rope model used in this work suggests an even lower number of rotations.

Online De-Radicalization? Countering Violent Extremist Narratives: Message, Messenger and Media Strategy

Directory of Open Access Journals (Sweden)

Omar Ashour

2011-01-01

Full Text Available Is “online de-radicalization” possible? Given the two growing phenomena of “online radicalization” and “behavioral/ideological/organizational de-radicalization,” this article outlines a broad strategy for countering the narratives of violent extremists. It argues that an effective counter-narrative should be built on three pillars. The first is an effective comprehensive message that dismantles and counter-argues against every dimension of the extremist narrative, namely the theological, political, historical, instrumental and socio-psychological dimensions. The second pillar is the messengers. The article argues that for the first time in the history of Jihadism a “critical mass” of former militants, who rebelled not only against the current behaviour of their former colleagues but also against the ideology supporting it, has come into existence. This “critical mass” can constitute the core of credible messengers, especially the few de-radicalized individuals and groups that still maintain influence and respect among vulnerable communities. The third pillar is the dissemination and attraction strategy of the counter-narratives(s which focuses on the role of the media. The author of the article outlines a broad framework, which is a part of a UN-sponsored, comprehensive research project on countering the extremists narrative.

Exosomes as divine messengers: are they the Hermes of modern molecular oncology?

Science.gov (United States)

Braicu, C; Tomuleasa, C; Monroig, P; Cucuianu, A; Berindan-Neagoe, I; Calin, G A

2015-01-01

Exosomes are cell-derived vesicles that convey key elements with the potential to modulate intercellular communication. They are known to be secreted from all types of cells, and are crucial messengers that can regulate cellular processes by ‘trafficking' molecules from cells of one tissue to another. The exosomal content has been shown to be broad, composed of different types of cytokines, growth factors, proteins, or nucleic acids. Besides messenger RNA (mRNA) they can also contain noncoding transcripts such as microRNAs (miRNAs), which are small endogenous cellular regulators of protein expression. In diseases such as cancer, exosomes can facilitate tumor progression by altering their vesicular content and supplying the tumor niche with molecules that favor the progression of oncogenic processes such as proliferation, invasion and metastasis, or even drug resistance. The packaging of their molecular content is known to be tissue specific, a fact that makes them interesting tools in clinical diagnostics and ideal candidates for biomarkers. In the current report, we describe the main properties of exosomes and explain their involvement in processes such as cell differentiation and cell death. Furthermore, we emphasize the need of developing patient-targeted treatments by applying the conceptualization of exosomal-derived miRNA-based therapeutics. PMID:25236394

Navigating the MESSENGER Spacecraft through End of Mission

Science.gov (United States)

Bryan, C. G.; Williams, B. G.; Williams, K. E.; Taylor, A. H.; Carranza, E.; Page, B. R.; Stanbridge, D. R.; Mazarico, E.; Neumann, G. A.; O'Shaughnessy, D. J.; McAdams, J. V.; Calloway, A. B.

2015-12-01

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft orbited the planet Mercury from March 2011 until the end of April 2015, when it impacted the planetary surface after propellant reserves used to maintain the orbit were depleted. This highly successful mission was led by the principal investigator, Sean C. Solomon, of Columbia University. The Johns Hopkins University Applied Physics Laboratory (JHU/APL) designed and assembled the spacecraft and served as the home for spacecraft operations. Spacecraft navigation for the entirety of the mission was provided by the Space Navigation and Flight Dynamics Practice (SNAFD) of KinetX Aerospace. Orbit determination (OD) solutions were generated through processing of radiometric tracking data provided by NASA's Deep Space Network (DSN) using the MIRAGE suite of orbital analysis tools. The MESSENGER orbit was highly eccentric, with periapsis at a high northern latitude and periapsis altitude in the range 200-500 km for most of the orbital mission phase. In a low-altitude "hover campaign" during the final two months of the mission, periapsis altitudes were maintained within a narrow range between about 35 km and 5 km. Navigating a spacecraft so near a planetary surface presented special challenges. Tasks required to meet those challenges included the modeling and estimation of Mercury's gravity field and of solar and planetary radiation pressure, and the design of frequent orbit-correction maneuvers. Superior solar conjunction also presented observational modeling issues. One key to the overall success of the low-altitude hover campaign was a strategy to utilize data from an onboard laser altimeter as a cross-check on the navigation team's reconstructed and predicted estimates of periapsis altitude. Data obtained from the Mercury Laser Altimeter (MLA) on a daily basis provided near-real-time feedback that proved invaluable in evaluating alternative orbit estimation strategies, and

Synaptic plasticity in the medial vestibular nuclei: role of glutamate receptors and retrograde messengers in rat brainstem slices.

Science.gov (United States)

Grassi, S; Pettorossi, V E

2001-08-01

The analysis of cellular-molecular events mediating synaptic plasticity within vestibular nuclei is an attempt to explain the mechanisms underlying vestibular plasticity phenomena. The present review is meant to illustrate the main results, obtained in vitro, on the mechanisms underlying long-term changes in synaptic strength within the medial vestibular nuclei. The synaptic plasticity phenomena taking place at the level of vestibular nuclei could be useful for adapting and consolidating the efficacy of vestibular neuron responsiveness to environmental requirements, as during visuo-vestibular recalibration and vestibular compensation. Following a general introduction on the most salient features of vestibular compensation and visuo-vestibular adaptation, which are two plastic events involving neuronal circuitry within the medial vestibular nuclei, the second and third sections describe the results from rat brainstem slice studies, demonstrating the possibility to induce long-term potentiation and depression in the medial vestibular nuclei, following high frequency stimulation of the primary vestibular afferents. In particular the mechanisms sustaining the induction and expression of vestibular long-term potentiation and depression, such as the role of various glutamate receptors and retrograde messengers have been described. The relevant role of the interaction between the platelet-activating factor, acting as a retrograde messenger, and the presynaptic metabotropic glutamate receptors, in determining the full expression of vestibular long-term potentiation is also underlined. In addition, the mechanisms involved in vestibular long-term potentiation have been compared with those leading to long-term potentiation in the hippocampus to emphasize the most significant differences emerging from vestibular studies. The fourth part, describes recent results demonstrating the essential role of nitric oxide, another retrograde messenger, in the induction of vestibular

Photometric data from some photographs of Mars obtained with the Automatic Interplanetary Station 'Mars 3'

International Nuclear Information System (INIS)

Botvinova, V.V.; Bugaenko, O.I.; Koval, I.K.; Narajeva, M.K.; Selivanov, A.S.

1974-01-01

The results of detailed photometric treatment of Mars photographs obtained with the Automatic Interplanetary Station 'Mars 3' in three wavelengths are given. Photometric maps of the Martian surface have been constructed; a thin layer observed near the limb has been investigated. (Auth.)

Interplanetary electrons: what is the strength of the Jupiter source

International Nuclear Information System (INIS)

Fillius, W.; Ip, Wing-Huen; Knickerbocker, P.

1977-01-01

Because there is not enough information to support a rigorous answer, we use a phenomenological approach and conservative assumptions to address the source strength of Jupiter for interplanetary electrons. We estimate that Jupiter emits approximately 10 24 - 10 26 electrons s -1 of energy > 6 MeV, which source may be compared with the population of approximately 3 x 10 28 electrons of the same energy in Jupiter's outer magnetosphere. We conclude that Jupiter accelerates particles at a rate exceeding that of ordinary trapped particle dynamical processes. (author)

Coronal mass ejections, interplanetary shocks in relation with forbush decreases associated with intense geomagnetic storms

International Nuclear Information System (INIS)

Verma, P L; Patel, Nand Kumar; Prajapati, Mateswari

2014-01-01

Coronal mass ejections (CMEs} are the most energetic solar events in which large amount of solar plasma materials are ejected from the sun into heliosphere, causing major disturbances in solar wind plasma, Interplanetary shocks, Forbush decrease(Fds) in cosmic ray intensity and geomagnetic storms. We have studied Forbush decreases associated with intense geomagnetic storms observed at Oulu super neutron monitor, during the period of May 1998-Dec 2006 with coronal mass ejections (CMEs), X-ray solar flares and interplanetary shocks. We have found that all the (100%) Forbush decreases associated with intense geomagnetic storms are associated with halo and partial halo coronal mass ejections (CMEs). The association rate between halo and partial halo coronal mass ejections are found 96.00%and 04.00% respectively. Most of the Forbush decreases associated with intense geomagnetic storms (96.29%) are associated with X-ray solar flares of different categories . The association rates for X-Class, M-Class, and C- Class X -ray solar flares are found 34.62%, 50.00% and 15.38% respectively .Further we have concluded that majority of the Forbush decrease associated with intense geomagnetic storms are related to interplanetary shocks (92.30 %) and the related shocks are forward shocks. We have found positive co-relation with co-relation co-efficient .7025 between magnitudes of Forbush decreases associated with intense geomagnetic storms and speed of associated coronal mass ejections. Positive co-relation with co-relation co-efficient 0.48 has also been found between magnitudes of intense geomagnetic storms and speed of associated coronal mass ejections.

Tissue distribution of human acetylcholinesterase and butyrylcholinesterase messenger RNA

Energy Technology Data Exchange (ETDEWEB)

Jbilo, O.; Barteles, C.F.; Chatonnet, A.; Toutant, J.P.; Lockridge, O.

1994-12-31

Tissue distribution of human acetyicholinesterase and butyryicholinesterase messenger RNA. 1 Cholinesterase inhibitors occur naturally in the calabar bean (eserine), green potatoes (solanine), insect-resistant crab apples, the coca plant (cocaine) and snake venom (fasciculin). There are also synthetic cholinesterase inhibitors, for example man-made insecticides. These inhibitors inactivate acetyicholinesterase and butyrylcholinesterase as well as other targets. From a study of the tissue distribution of acetylcholinesterase and butyrylcholinesterase mRNA by Northern blot analysis, we have found the highest levels of butyrylcholinesterase mRNA in the liver and lungs, tissues known as the principal detoxication sites of the human body. These results indicate that butyrylcholinesterase may be a first line of defense against poisons that are eaten or inhaled.

Multi-spacecraft Observations of the Coronal and Interplanetary Evolution of a Solar Eruption Associated with Two Active Regions

Energy Technology Data Exchange (ETDEWEB)

Hu, Huidong; Liu, Ying D.; Wang, Rui; Zhao, Xiaowei; Zhu, Bei; Yang, Zhongwei, E-mail: liuxying@spaceweather.ac.cn [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China)

2017-05-10

We investigate the coronal and interplanetary evolution of a coronal mass ejection (CME) launched on 2010 September 4 from a source region linking two active regions (ARs), 11101 and 11103, using extreme ultraviolet imaging, magnetogram, white-light, and in situ observations from SDO , STEREO , SOHO , VEX , and Wind . A potential-field source-surface model is employed to examine the configuration of the coronal magnetic field surrounding the source region. The graduated cylindrical shell model and a triangulation method are applied to determine the kinematics of the CME in the corona and interplanetary space. From the remote sensing and in situ observations, we obtain some key results: (1) the CME was deflected in both the eastward and southward directions in the low corona by the magnetic pressure from the two ARs, and possibly interacted with another ejection, which caused that the CME arrived at VEX that was longitudinally distant from the source region; (2) although VEX was closer to the Sun, the observed and derived CME arrival times at VEX are not earlier than those at Wind , which suggests the importance of determining both the frontal shape and propagation direction of the CME in interplanetary space; and (3) the ICME was compressed in the radial direction while the longitudinal transverse size was extended.

Behaviour of the interplanetary and magnetospheric electric fields during very intense storms

International Nuclear Information System (INIS)

Wu, Lei; Gendrin, R.; Higel, B.

1982-01-01

A study is made of the role which a positive (northward) component of the interplanetary magnetic field (IMF) Bsub(z) may play in triggering large magnetic storms. The study is made over a 15 year period (1964-1978) by selecting storms with Ksub(p) >= 7 0 and which are preceded by a Sudden Commencement (Ssc). The correlation between the geomagnetic index Ksub(m) and the three-hourly averaged Bsub(z) is established both on a statistical basis and on a case-by-case study. Storms associated with Bsub(z) > 0 are found to be less intense than those associated with Bsub(z) < 0, but major storms can be also triggered by solar wind events associated with a northward IMF. The relation-ship between interplanetary electric field Esub(γ) and Ksub(m) is also given. By using this relation together with the one between Esub(M) and Ksub(m) which has been established in previous studies (where Esub(M) is the magnetospheric convection electric field), it is possible to study the transfer efficiency of the magnetosphere. It is found that the transfer coefficient ΔEsub(M)/ΔEsub(γ) is much smaller for intense storms than for moderate ones, the latter having been studied in a previous paper (Wu Lei et al., 1981)

Interplanetary Type III Bursts and Electron Density Fluctuations in the Solar Wind

Science.gov (United States)

Krupar, V.; Maksimovic, M.; Kontar, E. P.; Zaslavsky, A.; Santolik, O.; Soucek, J.; Kruparova, O.; Eastwood, J. P.; Szabo, A.

2018-04-01

Type III bursts are generated by fast electron beams originated from magnetic reconnection sites of solar flares. As propagation of radio waves in the interplanetary medium is strongly affected by random electron density fluctuations, type III bursts provide us with a unique diagnostic tool for solar wind remote plasma measurements. Here, we performed a statistical survey of 152 simple and isolated type III bursts observed by the twin-spacecraft Solar TErrestrial RElations Observatory mission. We investigated their time–frequency profiles in order to retrieve decay times as a function of frequency. Next, we performed Monte Carlo simulations to study the role of scattering due to random electron density fluctuations on time–frequency profiles of radio emissions generated in the interplanetary medium. For simplification, we assumed the presence of isotropic electron density fluctuations described by a power law with the Kolmogorov spectral index. Decay times obtained from observations and simulations were compared. We found that the characteristic exponential decay profile of type III bursts can be explained by the scattering of the fundamental component between the source and the observer despite restrictive assumptions included in the Monte Carlo simulation algorithm. Our results suggest that relative electron density fluctuations /{n}{{e}} in the solar wind are 0.06–0.07 over wide range of heliospheric distances.

Early changes of placenta-derived messenger RNA in maternal plasma – potential value for preeclampsia prediction?

Directory of Open Access Journals (Sweden)

Surugiu Sebastian

2015-12-01

Full Text Available Objective: the pourpose of the study was to determine if there are any differences between placenta derived plasmatic levels of messenger RNA in normal and future preeclamptic pregnancies and if these placental transcripts can predict preeclampsia long before clinical onset

MESSENGER Observations of the Spatial Distribution of Planetary Ions Near Mercury

Science.gov (United States)

Zurbuchen, Thomas H.; Raines, Jim M.; Slavin, James A.; Gershman, Daniel J.; Gilbert, Jason A.; Gloeckler, George; Anderson, Brian J.; Baker, Daniel N.; Korth, Haje; Krimigis, Stamatios M.;

Analysis of an Interplanetary Coronal Mass Ejection by a Spacecraft Radio Signal: A Case Study

Science.gov (United States)

Molera Calvés, G.; Kallio, E.; Cimo, G.; Quick, J.; Duev, D. A.; Bocanegra Bahamón, T.; Nickola, M.; Kharinov, M. A.; Mikhailov, A. G.

2017-11-01

Tracking radio communication signals from planetary spacecraft with ground-based telescopes offers the possibility to study the electron density and the interplanetary scintillation of the solar wind. Observations of the telemetry link of planetary spacecraft have been conducted regularly with ground antennae from the European Very Long Baseline Interferometry Network, aiming to study the propagation of radio signals in the solar wind at different solar elongations and distances from the Sun. We have analyzed the Mars Express spacecraft radio signal phase fluctuations while, based on a 3-D heliosphere plasma simulation, an interplanetary coronal mass ejection (ICME) crossed the radio path during one of our observations on 6 April 2015. Our measurements showed that the phase scintillation indices increased by a factor of 4 during the passage of the ICME. The method presented here confirms that the phase scintillation technique based on spacecraft signals provides information of the properties and propagation of the ICMEs in the heliosphere.

A shock surface geometry - The February 15-16, 1967, event. [solar flare associated interplanetary shock

Science.gov (United States)

Lepping, R. P.; Chao, J. K.

1976-01-01

An estimated shape is presented for the surface of the flare-associated interplanetary shock of February 15-16, 1967, as seen in the ecliptic-plane cross section. The estimate is based on observations by Explorer 33 and Pioneers 6 and 7. The estimated shock normal at the Explorer 33 position is obtained by a least-squares shock parameter-fitting procedure for that satellite's data; the shock normal at the Pioneer 7 position is found by using the magnetic coplanarity theorem and magnetic-field data. The average shock speed from the sun to each spacecraft is determined along with the local speed at Explorer 33 and the relations between these speeds and the position of the initiating solar flare. The Explorer 33 shock normal is found to be severely inclined and not typical of interplanetary shocks. It is shown that the curvature of the shock surface in the ecliptic plane near the earth-Pioneer 7 region is consistent with a radius of not more than 0.4 AU.

The Ultimate Destination: Choice of Interplanetary Exploration Path can define Future of Interstellar Spaceflight

Science.gov (United States)

Silin, D. V.

Manned interstellar spaceflight is facing multiple challenges of great magnitude; among them are extremely large distances and the lack of known habitable planets other than Earth. Many of these challenges are applicable to manned space exploration within the Solar System to the same or lesser degree. If these issues are resolved on an interplanetary scale, better position to pursue interstellar exploration can be reached. However, very little progress (if any) was achieved in manned space exploration since the end of Space Race. There is no lack of proposed missions, but all of them require considerable technological and financial efforts to implement while yielding no tangible benefits that would justify their costs. To overcome this obstacle highest priority in future space exploration plans should be assigned to the creation of added value in outer space. This goal can be reached if reductions in space transportation, construction and maintenance of space-based structures costs are achieved. In order to achieve these requirements several key technologies have to be mastered, such as near-Earth object mining, space- based manufacturing, agriculture and structure assembly. To keep cost and difficulty under control next exploration steps can be limited to nearby destinations such as geostationary orbit, low lunar orbit, Moon surface and Sun-Earth L1 vicinity. Completion of such a program will create a solid foundation for further exploration and colonization of the Solar System, solve common challenges of interplanetary and interstellar spaceflight and create useful results for the majority of human population. Another important result is that perception of suitable destinations for interstellar missions will change significantly. If it becomes possible to create habitable and self-sufficient artificial environments in the nearby interplanetary space, Earth-like habitable planets will be no longer required to expand beyond our Solar System. Large fraction of the

Interplanetary magnetic field according to measurements on the Fobos-1,-2 space vehicles. 3. Heliospheric substorm of August 5-7, 1988

International Nuclear Information System (INIS)

Ivanov, K.G.

1995-01-01

Three-phase disturbance of the interplanetary magnetic field was observed by FOBOS-1 and Fobos-2 space vehicles being at 10 million km distance from the Earth and by IMP-8 near-the-Earth satellite. Disturbance configuration and structure demonstrate that passing of nonstandard bend of heliospheric current layer is the reason of it. Structure, intensity and origination of disturbance enable to classify it as belonging to a category of heliospheric substorms. All three phases of interplanetary disturbance were represented in special near-the-Earth geomagnetic variations of polar cap. 9 refs

Trailblazing Medicine Sustaining Explorers During Interplanetary Missions

CERN Document Server

Seedhouse, Erik

2011-01-01

To prepare for the day when astronauts leave low-Earth orbit for long-duration exploration missions, space medicine experts must develop a thorough understanding of the effects of microgravity on the human body, as well as ways of mitigating them. To gain a complete understanding of the effects of space on the human body and to create tools and technologies required for successful exploration, space medicince will become an increasingly collaborative discipline incorporating the skills of physicians, biomedical scientists, engineers, and mission planners. Trailblazing Medicine examines the future of space medicine in relation to human space exploration; describes what is necessary to keep a crew alive in space, including the use of surgical robots, surface-based telemedicine, and remote emergency care; discusses bioethical problems such as euthanasia, sex, and precautionary surgery; investigates the medical challenges faced by interplanetary astronauts; details the process of human hibernation.

Van Allen Probes, THEMIS, GOES, and Cluster Observations of EMIC Waves, ULF Pulsations, and an Electron Flux Dropout

Science.gov (United States)

Sigsbee, K.; Kletzing, C. A.; Smith, C. W.; Macdowall, R.; Spence, H.; Reeves, G.; Blake, J. B.; Baker, D. N.; Green, J. C.; Singer, H. J.;

MESSENGER Orbital Observations of Large-Amplitude Kelvin-Helmholtz Waves at Mercury's Magnetopause

Science.gov (United States)

Sundberg, Torbjorn; Boardsen, Scott A.; Slavin, James A.; Anderson, Brian J.; Korth, Haje; Zurbuchen, Thomas H.; Raines, Jim M.; Solomon, Sean C.

2012-01-01

We present a survey of Kelvi\\ n-Helmholtz (KH) waves at Mercury's magnetopause during MESSENGER's first Mercury year in orb it. The waves were identified on the basis of the well-established sawtooth wave signatures that are associated with non-linear KH vortices at the magnetopause. MESSENGER frequently observed such KH waves in the dayside region of the magnetosphere where the magnetosheath flow velocity is still sub -sonic, which implies that instability growth rates at Mercury's magnetopau are much larger than at Earth. We attribute these greater rates to the limited wave energy dissipation in Mercury's highly resistive regolith. The wave amplitude was often on the order of ' 00 nT or more, and the wave periods were - 10- 20 s. A clear dawn-dusk asymmetry is present in the data, in that all of the observed wave events occurred in the post-noon and dusk-side sectors of the magnetopause. This asymmetry is like ly related to finite Larmor-radius effects and is in agreement with results from particle-in-cell simulations of the instability. The waves were observed almost exclusively during periods when the north-south component of the magnetosheath magnetic field was northward, a pattern similar to that for most terrestrial KH wave events. Accompanying plasma measurements show that the waves were associated with the transport of magnetosheath plasma into the magnetosphere.

Radiation protection for human interplanetary spaceflight and planetary surface operations

Energy Technology Data Exchange (ETDEWEB)

Clark, B.C. [Armed Forces Radiobiology Research Inst., Bethesda, MD (United States)]|[DLR Inst. of Aerospace Medicine, Cologne (Germany)]|[NASA, Goddard Space Flight Center, Greenbelt, MD (United States)

1993-12-31

Radiation protection issues are reviewed for five categories of radiation exposure during human missions to the moon and Mars: trapped radiation belts, galactic cosmic rays, solar flare particle events, planetary surface emissions, and on-board radiation sources. Relative hazards are dependent upon spacecraft and vehicle configurations, flight trajectories, human susceptibility, shielding effectiveness, monitoring and warning systems, and other factors. Crew cabins, interplanetary mission modules, surface habitats, planetary rovers, and extravehicular mobility units (spacesuits) provide various degrees of protection. Countermeasures that may be taken are reviewed relative to added complexity and risks that they could entail, with suggestions for future research and analysis.

Suppressing gravitino thermal production with a temperature-dependent messenger coupling

International Nuclear Information System (INIS)

Badziak, Marcin; Dalianis, Ioannis; Lalak, Zygmunt

2016-01-01

We show that the constraints on GMSB theories from the gravitino cosmology can be significantly relaxed if the messenger-spurion coupling is temperature dependent. We demonstrate this novel mechanism in a scenario in which this coupling depends on the VEV of an extra singlet field S that interacts with the thermalized plasma which can result in a significantly suppressed gravitino production rate. In such a scenario the relic gravitino abundance is determined by the thermal dynamics of the S field and it is easy to fit the observed dark matter abundance evading the stringent constraints on the reheating temperature, thus making gravitino dark matter consistent with thermal leptogenesis.

An Integrated Tool for Low Thrust Optimal Control Orbit Transfers in Interplanetary Trajectories

Science.gov (United States)

Dargent, T.; Martinot, V.

In the last recent years a significant progress has been made in optimal control orbit transfers using low thrust electrical propulsion for interplanetary missions. The system objective is always the same: decrease the transfer duration and increase the useful satellite mass. The optimum control strategy to perform the minimum time to orbit or the minimum fuel consumption requires the use of sophisticated mathematical tools, most of the time dedicated to a specific mission and therefore hardly reusable. To improve this situation and enable Alcatel Space to perform rather quick trajectory design as requested by mission analysis, we have developed a software tool T-3D dedicated to optimal control orbit transfers which integrates various initial and terminal rendezvous conditions - e.g. fixed arrival time for planet encounter - and engine thrust profiles -e.g. thrust law variation with respect to the distance to the Sun -. This single and quite versatile tool allows to perform analyses like minimum consumption for orbit insertions around a planet from an hyperbolic trajectory, interplanetary orbit transfers, low thrust minimum time multiple revolution orbit transfers, etc… From a mathematical point of view, the software relies on the minimum principle formulation to find the necessary conditions of optimality. The satellite dynamics is a two body model and relies of an equinoctial formulation of the Gauss equation. This choice has been made for numerical purpose and to solve more quickly the two point boundaries values problem. In order to handle the classical problem of co-state variables initialization, problems simpler than the actual one can be solved straight forward by the tool and the values of the co-state variables are kept as first guess for a more complex problem. Finally, a synthesis of the test cases is presented to illustrate the capacities of the tool, mixing examples of interplanetary mission, orbit insertion, multiple revolution orbit transfers

Farm Women, Solidarity, and "The Suffrage Messenger": Nebraska Suffrage Activism on the Plains, 1915-1917

Science.gov (United States)

Heider, Carmen

2012-01-01

In 1914 Nebraska men once again voted against the amendment that would have granted full suffrage to Nebraska women. This article focuses on the three years immediately after that defeat. It explores the remaining seventeen issues of the "Suffrage Messenger" and asks the following question: how did the suffrage newspaper portray and…

Vector-like fields, messenger mixing and the Higgs mass in gauge mediation

Energy Technology Data Exchange (ETDEWEB)

Fischler, Willy; Tangarife, Walter [Department of Physics and Texas Cosmology Center,The University of Texas at Austin,TX 78712 (United States)

2014-05-30

In order to generate, in the context of gauge mediation, a Higgs mass around 126 GeV that avoids the little hierarchy problem, we explore a set of models where the messengers are directly coupled to new vector-like fields at the TeV scale in addition to the usual low energy degrees of freedom. We find that in this context, stop masses lighter than 2 TeV and large A-terms are generated, thereby improving issues of fine tuning.

Bifurcations in the interplay of messenger RNA, protein and nonprotein coding RNA

International Nuclear Information System (INIS)

Zhdanov, Vladimir P

2008-01-01

The interplay of messenger RNA (mRNA), protein, produced via translation of this RNA, and nonprotein coding RNA (ncRNA) may include regulation of the ncRNA production by protein and (i) ncRNA-protein association resulting in suppression of the protein regulatory activity or (ii) ncRNA-mRNA association resulting in degradation of the miRNA-mRNA complex. The kinetic models describing these two scenarios are found to predict bistability provided that protein suppresses the ncRNA formation

Experiment on the diagnostics of the interplanetary and magnetospheric plasma on the ''Venera-11, 12'' automatic interplanetary stations and the ''Prognoz 7'' artificial Earth satellite

International Nuclear Information System (INIS)

Vajsberg, O.L.; Gorn, L.S.; Ermolaev, Yu.I.

1979-01-01

Solar wind with the Earth magnetosphere are studied. The experiments have been carried out at the ''Venera 11'', ''Venera 12'' automatic interplanetary stations and at the ''Prognoz 7'' artificial satellite of the Earth in 1978-79 with the help of the three identical combined plasma spectrometers. The SCS spectrometer measures the electron, proton and α particle spectra in the energy ranges of 10-200 eV, 250-5000 eV, and 500-10000 eV, respectively. Examples of energy spectra of charged particles are presented. Some characteristics of solar wind and the Earth magnetosphere plasma are discussed

The acceleration of particles at propagating interplanetary shocks

Science.gov (United States)

Prinsloo, P. L.; Strauss, R. D. T.

2017-12-01

Enhancements of charged energetic particles are often observed at Earth following the eruption of coronal mass ejections (CMEs) on the Sun. These enhancements are thought to arise from the acceleration of those particles at interplanetary shocks forming ahead of CMEs, propagating into the heliosphere. In this study, we model the acceleration of these energetic particles by solving a set of stochastic differential equations formulated to describe their transport and including the effects of diffusive shock acceleration. The study focuses on how acceleration at halo-CME-driven shocks alter the energy spectra of non-thermal particles, while illustrating how this acceleration process depends on various shock and transport parameters. We finally attempt to establish the relative contributions of different seed populations of energetic particles in the inner heliosphere to observed intensities during selected acceleration events.

Reply to Comment on ``Effects of fast and slow solar wind on the correlations between interplanetary medium and geomagnetic activity'' by C. B. Wang and J. K. Chao

Science.gov (United States)

Ballatore, Paola

2003-10-01

The paper [2002] (the paper commented) shows that the statistical significance of the correlations between the interplanetary parameters and the geomagnetic indices (Kp or Dst) is generally less significant during the fastest solar wind. On the other hand, at these fast solar wind periods, the significance of the Kp versus Dst correlation is equal to or higher than during slower solar wind. These results, together with further observations related to substorm periods and with previously published findings, are interpreted in terms of a difference in the interplanetary-magnetospheric coupling for solar wind faster or slower than a certain threshold (identified between about 500 and 600 km/s). Specifically, it is suggested that a possible linear approximation of the geomagnetic-interplanetary coupling is more appropriate during solar wind speed (Vsw) slower than this threshold, being nonlinear processes more dominant during the fastest speeds. This reply highlights that the correlation coefficients shown by [2003] are in agreement with these findings. In addition, Wang and Chao show that the statistical significance of the difference between the correlation coefficients for Vsw ≥ 550 km/s and those for Vsw Wang and Chao is wrong. Moreover, Wang and Chao recalculate the correlations between the interplanetary parameters and the ΔDst instead of Dst; in fact they note that the time derivative of this index (not the index itself) is driven by the interplanetary medium. Here we note that on the contrary, they show that the correlation coefficients between interplanetary parameters and Dst are larger than those obtained using ΔDst and we suggest a possible interpretation in terms of nonlinearity.

Distributed Interplanetary Delay/Disruption Tolerant Network (DTN) Monitor and Control System

Science.gov (United States)

Wang, Shin-Ywan

2012-01-01

The main purpose of Distributed interplanetary Delay Tolerant Network Monitor and Control System as a DTN system network management implementation in JPL is defined to provide methods and tools that can monitor the DTN operation status, detect and resolve DTN operation failures in some automated style while either space network or some heterogeneous network is infused with DTN capability. In this paper, "DTN Monitor and Control system in Deep Space Network (DSN)" exemplifies a case how DTN Monitor and Control system can be adapted into a space network as it is DTN enabled.

ANALISIS PREFERENSI KONSUMEN DALAM PENGGUNAAN SOCIAL MESSENGER DI KOTA BANDUNG TAHUN 2014 (Studi Kasus : LINE, KAKAOTALK, WECHAT, WHATSAPP

Directory of Open Access Journals (Sweden)

Noventi Ersa Putri

2017-03-01

Full Text Available Penelitian ini bertujuan untuk mengetahui “preferensi konsumen dalam penggunaan Social Messenger di kota Bandung”. Metode yang digunakan dalam penelitian ini adalah metode eksploratif dan deskriptif, dengan meng- gunakan teknik Nonprobability sampling dan purposive sampling, dengan jumlah sampel 384 responden. Analisis data yang digunakan adalah Conjoint Analysis. Hasil penelitian ini menunjukan bahwa keseluruhan responden menjadikan atribut fasilitas fi tur sebagai preferensi utama dalam memilih social messenger dengan nilai kepentingan tertinggi yaitu 48.361% dan level tertinggi yang menjadi preferensi fasilitas fi tur adalah free chat dengan nilai kepentingan sebesar 0.603% dan atribut desain sesuai kebutuhan pelanggan sebagai atribut terendah dengan nilai kepentingan 15.256% dan level ter- tinggi yang menjadi preferensi desain sesuai kebutuhan pelanggan adalah memiliki tampilan yang menarik dengan nilai kepentingan sebesar 0.078%.

Compression of the Venusian ionosphere on May 10, 1979, by the interplanetary shock generated by the solar eruption of May 8, 1979

International Nuclear Information System (INIS)

Dryer, M.; Perez-de-Tejada, H.; Taylor, H.A. Jr.; Intriligator, D.S.; Mihalov, J.D.; Rompolt, B.

1982-01-01

An interplanetary shock wave that was produced by a solar eruption and its associated coronal transient on May 8, 1979, has been 'tracked' through interplanetary space to a rendezvous 2 days later with Venus. The interaction of the shock wave with the ionospheric obstacle at Venus produced a significant compression of the dayside ionosphere. It is believed that the tracking, as it were, was accomplished for the first time via the diagnostic observations provided by Hα and white light imagery near the sun and the plasma and field measurements of two, nearly radially aligned, spacecraft

Interplanetary space transport using inertial fusion propulsion

International Nuclear Information System (INIS)

Orth, C.D.

1998-01-01

In this paper, we indicate how the great advantages that ICF offers for interplanetary propulsion can be accomplished with the VISTA spacecraft concept. The performance of VISTA is expected to surpass that from other realistic technologies for Mars missions if the energy gain achievable for ICF targets is above several hundred. Based on the good performance expected from the U. S. National Ignition Facility (NIF), the requirements for VISTA should be well within the realm of possibility if creative target concepts such as the fast ignitor can be developed. We also indicate that a 6000-ton VISTA can visit any planet in the solar system and return to Earth in about 7 years or less without any significant physiological hazards to astronauts. In concept, VISTA provides such short-duration missions, especially to Mars, that the hazards from cosmic radiation and zero gravity can be reduced to insignificant levels. VISTA therefore represents a significant step forward for space-propulsion concepts

Interplanetary Coronal Mass Ejections detected by HAWC

Science.gov (United States)

Lara, Alejandro

The High Altitude Water Cherenkov (HAWC) observatory is being constructed at the volcano Sierra Negra (4100 m a.s.l.) in Mexico. HAWC’s primary purpose is the study of both: galactic and extra-galactic sources of high energy gamma rays. HAWC will consist of 300 large water Cherenkov detectors (WCD), instrumented with 1200 photo-multipliers. The Data taking has already started while construction continues, with the completion projected for late 2014. The HAWC counting rate will be sensitive to cosmic rays with energies above the geomagnetic cutoff of the site (˜ 8 GV). In particular, HAWC will detect solar energetic particles known as Ground Level Enhancements (GLEs), and the effects of Coronal Mass Ejections on the galactic cosmic ray flux, known as Forbush Decreases. In this paper, we present a description of the instrument and its response to interplanetary coronal mass ejections, and other solar wind large scale structures, observed during the August-December 2013 period.

Cosmic ray anisotropy along with interplanetary transients

Science.gov (United States)

Mishra, Rajesh Kumar

The present work deals with the study of first three harmonics of low amplitude anisotropic wave trains of cosmic ray intensity over the period 1991-1994 for Deep River neutron monitoring station. It is observed that the diurnal time of maximum remains in the corotational direction; whereas, the time of maximum for both diurnal and semi-diurnal anisotropy has significantly shifted towards later hours as compared to the quiet day annual average for majority of the LAE events. It is noticed that these events are not caused either by the high-speed solar wind streams or by the sources on the Sun responsible for producing these streams; such as, polar coronal holes. The direction of the tri-diurnal anisotropy shows a good negative correlation with Bz component of interplanetary magnetic field. The occurrence of low amplitude events is dominant for positive polarity of Bz. The Disturbance Storm Time index i.e. Dst remains consistently negative only throughout the entire low amplitude wave train event.

Substorms and polar cap convection: the 10 January 2004 interplanetary CME case

Directory of Open Access Journals (Sweden)

Y. Andalsvik

2012-01-01

Full Text Available The expansion-contraction model of Dungey cell plasma convection has two different convection sources, i.e. reconnections at the magnetopause and in the magnetotail. The spatial-temporal structure of the nightside source is not yet well understood. In this study we shall identify temporal variations in the winter polar cap convection structure during substorm activity under steady interplanetary conditions. Substorm activity (electrojets and particle precipitations is monitored by excellent ground-satellite DMSP F15 conjunctions in the dusk-premidnight sector. We take advantage of the wide latitudinal coverage of the IMAGE chain of ground magnetometers in Svalbard – Scandinavia – Russia for the purpose of monitoring magnetic deflections associated with polar cap convection and substorm electrojets. These are augmented by direct observations of polar cap convection derived from SuperDARN radars and cross-track ion drift observations during traversals of polar cap along the dusk-dawn meridian by spacecraft DMSP F13. The interval we study is characterized by moderate, stable forcing of the magnetosphere-ionosphere system (EKL = 4.0–4.5 mV m−1; cross polar cap potential (CPCP, Φ (Boyle = 115 kV during Earth passage of an interplanetary CME (ICME, choosing an 4-h interval where the magnetic field pointed continuously south-west (Bz By By polarity of the ICME magnetic field, a clear indication of a nightside source.

On the use of a pulsed nuclear thermal rocket for interplanetary travel

OpenAIRE

Arias Montenegro, Francisco Javier

2016-01-01

The object of this work is a first assessment of the use of a pulsed nuclear thermal rocket for thrust and specific impulse (Isp) augmentation with particular reference to interplanetary travel. The basis of the novel space propulsion idea is the possibility of working in a bimodal fashion where the classical stationary nuclear thermal rocket (NTR) could be switch on or switch off as a pulsed reactor as desired by the mission planners. It was found that the key factor for Isp augmentation ...

Interplanetary scintillations of the 3C 279 radiosource from RATAN-600 observations

International Nuclear Information System (INIS)

Shishova, T.D.; Mingaliev, M.G.; AN SSSR, Nizhnij Arkhyz. Spetsial'naya Astrofizicheskaya Observatoriya)

1980-01-01

In 1976 and 1977 observations of interplanetary scintillations of the 3C 279 radiosource were carred out at the RATAN-600 at centimeter wavelengths. At Lambda=3.9 cm the index of scintillations gets suturated at the distance R approximately equal to 4 Rsub(Sun) from the Sun. The estimation of solar wind velocity is approximately 140 km/s at R=5Rsub(Sun); it grows up to approximately 400 km/s at R approximately equal to 10 Rsub(Sun)

On the equation of transport for cosmic-ray particles in the interplanetary region

International Nuclear Information System (INIS)

Webb, G.M.; Gleeson, L.J.

1979-01-01

Two new alternative derivations of the equation of transport for cosmic-ray particles in the interplanetary region are provided. Both derivations are carried out by using particle position r and time t in a frame of reference fixed in the solar system, and the particle momentum p' is specified relative to a local frame of reference moving with the solar wind. The first derivation is carried out by writing down a continuity equation for the cosmic rays, taking into account particle streaming and energy changes, and subsequently deriving the streaming and energy change terms in this equation. The momentum change term in the continuity equation, previously considered to be due to the adiabatic deceleration of particles in the expanding magnetic fields carried by the solar wing, appears in the present analysis as a dynamic effect in which the Lorentz force on the particle does not appear explicitly. An alternative derivation based on the ensemble averaged Liouville equation for charged particles in the stochastic interplanetary magnetic field using (r,p',t) as independent coordinates is also given. The latter derivation confirms the momentum change interpretation of the first derivation. A new derivation of the adiabatic rate as a combination of inverse-Fermi and betatron deceleration processes is also provided. (Auth.)

Energetic particle diffusion coefficients upstream of quasi-parallel interplanetary shocks

Science.gov (United States)

Tan, L. C.; Mason, G. M.; Gloeckler, G.; Ipavich, F. M.

1989-01-01

The properties of about 30 to 130-keV/e protons and alpha particles upstream of six quasi-parallel interplanetary shocks that passed by the ISEE 3 spacecraft during 1978-1979 were analyzed, and the values for the upstream energegic particle diffusion coefficient, kappa, in these six events were deduced for a number of energies and upstream positions. These observations were compared with predictions of Lee's (1983) theory of shock acceleration. It was found that the observations verified the prediction of the A/Q dependence (where A and Q are the particle atomic mass and ionization state, respectively) of kappa for alpha and proton particles upstream of the quasi-parallel shocks.

Enhanced interplanetary panspermia in the TRAPPIST-1 system.

Science.gov (United States)

Lingam, Manasvi; Loeb, Abraham

2017-06-27

We present a simple model for estimating the probability of interplanetary panspermia in the recently discovered system of seven planets orbiting the ultracool dwarf star TRAPPIST-1 and find that panspermia is potentially orders of magnitude more likely to occur in the TRAPPIST-1 system compared with the Earth-to-Mars case. As a consequence, we argue that the probability of abiogenesis is enhanced on the TRAPPIST-1 planets compared with the solar system. By adopting models from theoretical ecology, we show that the number of species transferred and the number of life-bearing planets are also likely to be higher because of the increased rates of immigration. We propose observational metrics for evaluating whether life was initiated by panspermia on multiple planets in the TRAPPIST-1 system. These results are also applicable to habitable exoplanets and exomoons in other planetary systems.

ALLTALK™- A Windows Phone Messenger With Cross Language Communication For Customer Care Services

OpenAIRE

Akhil Abraham; Royston Pinto

2014-01-01

In day to day life, messengers or chatting applications provide facility for instant messaging over the internet. Exchange of messages takes place in universally used languages like English, French, etc. where both the users know how to communicate in a common language. Thus chatting on mobile phones is a luxury when both the parties involved know a common language. When any company wants to provide customer care services to its customer they use mediums like talking to the cu...

Interplanetary Magnetic Field Control of the Entry of Solar Energetic Particles into the Magnetosphere

Science.gov (United States)

Richard, R. L.; El-Alaoui, M.; Ashour-Abdalla, M.; Walker, R. J.

2002-01-01

We have investigated the entry of energetic ions of solar origin into the magnetosphere as a function of the interplanetary magnetic field orientation. We have modeled this entry by following high energy particles (protons and 3 He ions) ranging from 0.1 to 50 MeV in electric and magnetic fields from a global magnetohydrodynamic (MHD) model of the magnetosphere and its interaction with the solar wind. For the most part these particles entered the magnetosphere on or near open field lines except for some above 10 MeV that could enter directly by crossing field lines due to their large gyroradii. The MHD simulation was driven by a series of idealized solar wind and interplanetary magnetic field (IMF) conditions. It was found that the flux of particles in the magnetosphere and transport into the inner magnetosphere varied widely according to the IMF orientation for a constant upstream particle source, with the most efficient entry occurring under southward IMF conditions. The flux inside the magnetosphere could approach that in the solar wind implying that SEPs can contribute significantly to the magnetospheric energetic particle population during typical SEP events depending on the state of the magnetosphere.

Two-step photoionization of hydrogen atoms in interplanetary space

International Nuclear Information System (INIS)

Gruntman, M.A.

1990-01-01

Photoionization is one of the key processes which determine the properties of fluxes of neutral atoms in interplanetary space. A new two-step channel (called indirect) of photoionization of hydrogen atoms is proposed. Hydrogen atoms are at first excited to states with principal quantum number n > 2, then decay to metastable H(2S) states, where they can be photoionized. Competing processes due to the interaction with solar wind plasma and solar radiation are considered and the photoionization rate through the proposed indirect channel is calculated. This rate depends on distance from the Sun as ∝ 1/R 4 at large distances (R > 1-2 a.u.) and as ∝ 1/R 2 at close approaches, where it is higher than the rate of direct photoionization. (author)

Multielement analysis of interplanetary dust particles using TOF-SIMS

Science.gov (United States)

Stephan, T.; Kloeck, W.; Jessberger, E. K.; Rulle, H.; Zehnpfenning, J.

1993-01-01

Sections of three stratospheric particles (U2015G1, W7029*A27, and L2005P9) were analyzed with TOF-SIMS (Time Of Flight-Secondary Ion Mass Spectrometry) continuing our efforts to investigate the element distribution in interplanetary dust particles (IDP's) with high lateral resolution (approximately 0.2 micron), to examine possible atmospheric contamination effects, and to further explore the abilities of this technique for element analysis of small samples. The samples, previously investigated with SXRF (synchrotron X-ray fluorescence analysis), are highly enriched in Br (Br/Fe: 59 x CI, 9.2 x CI, and 116 x CI, respectively). U2015G1 is the IDP with the by far highest Zn/Fe-ratio (81 x CI) ever reported in chondritic particles.

Characterization of the ER-Targeted Low Affinity Ca2+ Probe D4ER

Directory of Open Access Journals (Sweden)

Elisa Greotti

2016-09-01

Full Text Available Calcium ion (Ca2+ is a ubiquitous intracellular messenger and changes in its concentration impact on nearly every aspect of cell life. Endoplasmic reticulum (ER represents the major intracellular Ca2+ store and the free Ca2+ concentration ([Ca2+] within its lumen ([Ca2+]ER can reach levels higher than 1 mM. Several genetically-encoded ER-targeted Ca2+ sensors have been developed over the last years. However, most of them are non-ratiometric and, thus, their signal is difficult to calibrate in live cells and is affected by shifts in the focal plane and artifactual movements of the sample. On the other hand, existing ratiometric Ca2+ probes are plagued by different drawbacks, such as a double dissociation constant (Kd for Ca2+, low dynamic range, and an affinity for the cation that is too high for the levels of [Ca2+] in the ER lumen. Here, we report the characterization of a recently generated ER-targeted, Förster resonance energy transfer (FRET-based, Cameleon probe, named D4ER, characterized by suitable Ca2+ affinity and dynamic range for monitoring [Ca2+] variations within the ER. As an example, resting [Ca2+]ER have been evaluated in a known paradigm of altered ER Ca2+ homeostasis, i.e., in cells expressing a mutated form of the familial Alzheimer’s Disease-linked protein Presenilin 2 (PS2. The lower Ca2+ affinity of the D4ER probe, compared to that of the previously generated D1ER, allowed the detection of a conspicuous, more clear-cut, reduction in ER Ca2+ content in cells expressing mutated PS2, compared to controls.

Just How Important Is the Messenger versus the Message? The Case of Framing Physician-Assisted Suicide

Science.gov (United States)

Haider-Markel, Donald P.; Joslyn, Mark R.

2004-01-01

As a political issue, death and dying topics only sometimes reach the political agenda. However, some issues, such as physician-assisted suicide (PAS) have been highly salient. This article explores attitudes toward PAS by examining the malleability of opinion when respondents are exposed to issue frames and when specific messengers present those…

Effect of the Intelligent Health Messenger Box on health care professionals' knowledge, attitudes, and practice related to hand hygiene and hand bacteria counts.

Science.gov (United States)

Saffari, Mohsen; Ghanizadeh, Ghader; Fattahipour, Rasoul; Khalaji, Kazem; Pakpour, Amir H; Koenig, Harold G

2016-12-01

We assessed the effectiveness of the Intelligent Health Messenger Box in promoting hand hygiene using a quasiexperimental design. Knowledge, attitudes, and self-reported practices related to hand hygiene as well as hand bacteria counts and amount of liquid soap used were measured. The intervention involved broadcasting preventive audio messages. All outcomes showed significant change after the intervention compared with before. The Intelligent Health Messenger Box can serve as a practical way to improve hand hygiene. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

CAWSES November 7-8, 2004, Superstorm: Complex Solar and Interplanetary Features in the Post-Solar Maximum Phase

Science.gov (United States)

Tsurutani, Bruce T.; Echer, Ezequiel; Guarnieri, Fernando L.; Kozyra, J. U.

2008-01-01

The complex interplanetary structures during 7 to 8 Nov 2004 are analyzed to identify their properties as well as resultant geomagnetic effects and the solar origins. Three fast forward shocks, three directional discontinuities and two reverse waves were detected and analyzed in detail. The three fast forward shocks 'pump' up the interplanetary magnetic field from a value of approx.4 nT to 44 nT. However, the fields after the shocks were northward, and magnetic storms did not result. The three ram pressure increases were associated with major sudden impulses (SI + s) at Earth. A magnetic cloud followed the third forward shock and the southward Bz associated with the latter was responsible for the superstorm. Two reverse waves were detected, one at the edge and one near the center of the magnetic cloud (MC). It is suspected that these 'waves' were once reverse shocks which were becoming evanescent when they propagated into the low plasma beta MC. The second reverse wave caused a decrease in the southward component of the IMF and initiated the storm recovery phase. It is determined that flares located at large longitudinal distances from the subsolar point were the most likely causes of the first two shocks without associated magnetic clouds. It is thus unlikely that the shocks were 'blast waves' or that magnetic reconnection eroded away the two associated MCs. This interplanetary/solar event is an example of the extremely complex magnetic storms which can occur in the post-solar maximum phase.

The Mercury Laser Altimeter Instrument for the MESSENGER Mission

Science.gov (United States)

Cavanaugh, John F.; Smith, James C.; Sun, Xiaoli; Bartels, Arlin E.; Ramos-Izquierdo, Luis; Krebs, Danny J.; Novo-Gradac, Anne marie; McGarry, Jan F.; Trunzo, Raymond; Britt, Jamie L.

2006-01-01

The Mercury Laser Altimeter (MLA) is one of the payload science instruments on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission, which launched on 3 August 2004. The altimeter will measure the round trip time-of-flight of transmitted laser pulses reflected from the surface of the planet that, in combination with the spacecraft orbit position and pointing data, gives a high-precision measurement of surface topography referenced to Mercury's center of mass. The altimeter measurements will be used to determine the planet's forced librations by tracking the motion of large-scale topographic features as a function of time. MLA's laser pulse energy monitor and the echo pulse energy estimate will provide an active measurement of the surface reflectivity at 1064 nm. This paper describes the instrument design, prelaunch testing, calibration, and results of post-launch testing.

Space Travel is Utter Bilge: Early Ideas on Interplanetary Exploration

Science.gov (United States)

Yeomans, D. K.

2003-12-01

Until a few decades ago, interplanetary travel was the stuff of dreams but the dreamers often turned out to be farsighted while the predictions of some eminent scientists were far too conservative. The prescient dreamers include the Russian schoolteacher, Konstanin Tsiolkovsky who, in 1883, was the first to note that only rockets could serve the needs of space travel. In 1923, Herman Oberth published a treatise discussing various aspects of interplanetary travel including the impulse necessary to escape the Earth's gravitational pull. In his spare time, a German civil engineer, Walter Hohmann, established in 1925 that the optimal energy transfer orbit between planets is an ellipse that is tangent to the orbits of both bodies. Four year later, an Austrian army officer, Hermann Potocnik outlined the benefits of space stations including those in geosynchronous orbits. Whereas Tsiolkovsky, Oberth, Hohmann, and Potocnik provided ideas and theories, the American, Robert H. Goddard, was testing liquid fueled rockets by as early as 1925. By the time he was finished in 1941, Goddard flew liquid fueled rockets that reached speeds of 700 mph and altitudes above 8,000 feet. In direct contrast to the advances by these mostly amateur engineers, many respected authorities scoffed at space travel because of the insurmountable technological difficulties. One year prior to the launch of Sputnik, the British Astronomer Royal, Sir Richard Wooley, declared, "space travel is utter bilge." While the theories of space travel were well developed by the late 1920's, space travel technology was still a poorly funded, mostly amateur, endeavor until the German army hired Oberth's student, Werner von Braun, and others to develop long range rockets for military purposes. In the early 1940's, Von Braun's team developed the rocket propulsion and guidance systems that would one day form the basis of the American space program.

Fundamental issues on kappa-distributions in space plasmas and interplanetary proton distributions

International Nuclear Information System (INIS)

Leubner, M.P.

2004-01-01

Numerous in situ observations indicate clearly the presence of nonthermal electron and ion structures as ubiquitous and persistent feature in a variety of astrophysical plasma environments. In particular, the detected suprathermal particle populations are accurately represented by the family of κ-distributions, a power-law in particle speed. After clarifying the characteristics of high-energy tail distributions under various space plasma conditions, different generation mechanisms of energetic particles are introduced where numerical simulations of wave-particle interaction based on a Fokker-Planck approach demonstrate how Landau interaction ultimately leads to κ-like distributions. Because of lack of theoretical justification, the use of the analytical form of κ-functions was frequently criticized. It is shown that these distributions turn out as consequence of an entropy generalization favored by nonextensive thermo-statistics, thus providing the missing link for powerlaw models of suprathermal tails from fundamental physics, along with a physical interpretation of the structure parameter κ. Moreover, with regard to the full nonextensive formalism, compatible also with negative values of κ, it is demonstrated that core-halo distribution structures, as observed for instance under typical interplanetary plasma conditions, are a natural content of the pseudo-additive entropy concept. The significance of the complete κ-distribution family with regard to observed core-halo electron and double-humped ion velocity space characteristics is illuminated, where the observed peak separation scale of interplanetary proton distributions is compatible with a maximum entropy condition

Interplanetary type II radio bursts and their association with CMEs and flares

Science.gov (United States)

Shanmugaraju, A.; Suresh, K.; Vasanth, V.; Selvarani, G.; Umapathy, S.

2018-06-01

We study the characteristics of the CMEs and their association with the end-frequency of interplanetary (IP)-type-II bursts by analyzing a set of 138 events (IP-type-II bursts-flares-CMEs) observed during the period 1997-2012. The present analysis consider only the type II bursts having starting frequency < 14 MHz to avoid the extension of coronal type IIs. The selected events are classified into three groups depending on the end-frequency of type IIs as follows, (A) Higher, (B) Intermediate and (C) Lower end-frequency. We compare characteristics of CMEs, flares and type II burst for the three selected groups of events and report some of the important differences. The observed height of CMEs is compared with the height of IP type IIs estimated using the electron density models. By applying a density multiplier (m) to this model, the density has been constrained both in the upper corona and in the interplanetary medium, respectively as m= 1 to 10 and m = 1 to 3. This study indicates that there is a correlation between the observed CME height and estimated type II height for groups B and C events whereas this correlation is absent in group A. In all the groups (A, B & C), the different heights of CMEs and type II reveal that the type IIs are not only observed at the nose but also at the flank of the CMEs.

THE INTERPLANETARY NETWORK RESPONSE TO LIGO GW150914

Energy Technology Data Exchange (ETDEWEB)

Hurley, K. [University of California, Berkeley, Space Sciences Laboratory, 7 Gauss Way, Berkeley, CA 94720-7450 (United States); Svinkin, D. S.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D. [Ioffe Physical Technical Institute, Politekhnicheskaya 26, St. Petersburg 194021 (Russian Federation); Boynton, W. [University of Arizona, Department of Planetary Sciences, Tucson, AZ 85721 (United States); Mitrofanov, I. G.; Golovin, D. V.; Kozyrev, A. S.; Litvak, M. L.; Sanin, A. B. [Space Research Institute, 84/32, Profsoyuznaya, Moscow 117997 (Russian Federation); Rau, A.; Kienlin, A. von; Zhang, X. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, Postfach 1312, Garching, D-85748 Germany (Germany); Connaughton, V.; Meegan, C. [University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Cline, T.; Gehrels, N., E-mail: khurley@ssl.berkeley.edu [NASA Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 (United States)

2016-09-20

We have performed a blind search for a gamma-ray transient of arbitrary duration and energy spectrum around the time of the LIGO gravitational-wave event GW150914 with the six-spacecraft interplanetary network (IPN). Four gamma-ray bursts were detected between 30 hr prior to the event and 6.1 hr after it, but none could convincingly be associated with GW150914. No other transients were detected down to limiting 15–150 keV fluences of roughly 5 ×10{sup −8}–5 × 10{sup −7} erg cm{sup −2}. We discuss the search strategies and temporal coverage of the IPN on the day of the event and compare the spatial coverage to the region where GW150914 originated. We also report the negative result of a targeted search for the Fermi -GBM event reported in conjunction with GW150914.

Opening a Window on ICME-driven GCR Modulation in the Inner Solar System

Science.gov (United States)

Winslow, Reka M.; Schwadron, Nathan A.; Lugaz, Noé; Guo, Jingnan; Joyce, Colin J.; Jordan, Andrew P.; Wilson, Jody K.; Spence, Harlan E.; Lawrence, David J.; Wimmer-Schweingruber, Robert F.; Mays, M. Leila

2018-04-01

Interplanetary coronal mass ejections (ICMEs) often cause Forbush decreases (Fds) in the flux of galactic cosmic rays (GCRs). We investigate how a single ICME, launched from the Sun on 2014 February 12, affected GCR fluxes at Mercury, Earth, and Mars. We use GCR observations from MESSENGER at Mercury, ACE/LRO at the Earth/Moon, and MSL at Mars. We find that Fds are steeper and deeper closer to the Sun, and that the magnitude of the magnetic field in the ICME magnetic ejecta as well as the “strength” of the ICME sheath both play a large role in modulating the depth of the Fd. Based on our results, we hypothesize that (1) the Fd size decreases exponentially with heliocentric distance, and (2) that two-step Fds are more common closer to the Sun. Both hypotheses will be directly verifiable by the upcoming Parker Solar Probe and Solar Orbiter missions. This investigation provides the first systematic study of the changes in GCR modulation as a function of distance from the Sun using nearly contemporaneous observations at Mercury, Earth/Moon, and Mars, which will be critical for validating our physical understanding of the modulation process throughout the heliosphere.

Observations of interplanetary energetic ion enhancements near magnetic sector boundaries

International Nuclear Information System (INIS)

Briggs, P.R.; Armstrong, T.P.

1984-01-01

We have examined all energetic medium nuclei (carbon, nitrogen, and oxygen) flux increases observed all the satellites IMP 7 and IMP 8 at 1 AU during Bartels rotations 1906-1974. After removing flare-related increases, the remaining 14 ''events'' were compared to interplanetary magnetic field and solar wind parameters. We have discovered a class of flux enhancements in which the ion increases occur close to the onset of magnetic sector boundary crossings. We interpret this observation as a facilitated access to 1 AU of energetic ions from the corona or chromopshere via the magnetic sector structure. It appears that this access is more significant for medium than for lighter nuclei, ''suggesting a possible charge- or rigidity-dependent transport mechanism

Intensity of low-frequency radiations and the interplanetary magnetic field

International Nuclear Information System (INIS)

Larkina, V.I.; Likhter, Ya.I.

1983-01-01

The data of measurements of ELF/VLF radiations at ''Interkosmos-13'' artificial Earth satellite in auroral latitudes and in the polar cap in the vernal equinox of 1975 are compared with characteristics of interplanetary magnetic field (IMF). The absence of north-south asymmetry of variations of ELF/VLF-radiation Intensity in the outer ionosphere versus the IMF characteristics is noted. The intensity of natural ELF- and VLF-radiations depends in a complex way on parameters of the magnetospheric plasma: composition and concentration of ''cold'' particles, geomagnetic field intensity, properties of energetic particle fluxes. The considered variations in the radiation amplitude versus the IMF characteristics show the predominant role of the sector structure polarity and IMF Bsub(y) component sign

The MESSENGER mission to Mercury: new insights into geological processes and evolution

Science.gov (United States)

Head, James W., III; Solomon, Sean C.; McNutt, Ralph L., Jr.; Blewett, David T.; Chapman, Clark R.; Domingue, Deborah L.; Evans, Larry G.; Gillis-Davis, Jeffrey J.; Hawkins, S. Edward, III; Helbert, Jörn; Holsclaw, Gregory M.; Izenberg, Noam R.; McClintock, William E.; McCoy, Timothy J.; Merline, William J.; Murchie, Scott L.; Nittler, Larrz R.; Phillips, Roger J.; Prockter, Louise M.; Robinson, Mark S.; Sprague, Ann L.; Strom, Robert G.; Vilas, Faith; Watters, Thomas R.; Zuber, Maria T.

2008-09-01

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission, a part of NASA's Discovery Program, was designed to answer six questions [1]: (1) What planetary formational processes led to Mercury's high ratio of metal to silicate? (2) What is the geological history of Mercury? (3) What are the nature and origin of Mercury's magnetic field? (4) What are the structure and state of Mercury's core? (5) What are the radar-reflective materials at Mercury's poles? (6) What are the important volatile species and their sources and sinks near Mercury? MESSENGER is currently midway through a complex interplanetary cruise phase that involves three flybys of Mercury. The first of these, on 14 January 2008, provided important new information relating to several of the questions above [2-13]. Here we summarize observations made during the flyby that are most relevant to new insights about geological processes that have operated on Mercury and implications for the planet's history [3, 8-13]. The instruments that provided the most direct information on the geological history of Mercury during this first encounter were the Mercury Dual Imaging System (MDIS) [14], the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) [15], and the Mercury Laser Altimeter (MLA) [16]. Among the many specific questions remaining following the Mariner 10 mission to Mercury (1974- 1975) were (1) the level of mineralogical and compositional diversity of the crust, which appeared relatively bland in Mariner 10 data, (2) the nature of the rest of the huge Caloris impact basin seen only partially in Mariner 10 images, (3) the origin of the extensive plains observed on the surface (ponded impact ejecta or extrusive lava flows?), (4) the diversity and global distribution of tectonic features that have deformed the crust and their implications for strain as a function of time, and (5) the bombardment chronology and geological history of Mercury [1, 17-19]. The viewing

Combined Multipoint Remote and In Situ Observations of the Asymmetric Evolution of a Fast Solar Coronal Mass Ejection

OpenAIRE

Rollett, T.; Moestl, C.; Temmer, M.; Frahm, R. A.; Davies, J. A.; Veronig, A. M.; Vrsnak, B.; Amerstorfer, U. V.; Farrugia, C. J.; Zic, T.; Zhang, T. L.

2014-01-01

We present an analysis of the fast coronal mass ejection (CME) of 2012 March 7, which was imaged by both STEREO spacecraft and observed in situ by MESSENGER, Venus Express, Wind and Mars Express. Based on detected arrivals at four different positions in interplanetary space, it was possible to strongly constrain the kinematics and the shape of the ejection. Using the white-light heliospheric imagery from STEREO-A and B, we derived two different kinematical profiles for the CME by applying the...

BACODINE/3rd Interplanetary Network burst localization

International Nuclear Information System (INIS)

Hurley, K.; Barthelmy, S.; Butterworth, P.; Cline, T.; Sommer, M.; Boer, M.; Niel, M.; Kouveliotou, C.; Fishman, G.; Meegan, C.

1996-01-01

Even with only two widely separated spacecraft (Ulysses and GRO), 3rd Interplanetary Network (IPN) localizations can reduce the areas of BATSE error circles by two orders of magnitude. Therefore it is useful to disseminate them as quickly as possible following BATSE bursts. We have implemented a system which transmits the light curves of BACODINE/BATSE bursts directly by e-mail to UC Berkeley immediately after detection. An automatic e-mail parser at Berkeley watches for these notices, determines the Ulysses crossing time window, and initiates a search for the burst data on the JPL computer as they are received. In ideal cases, it is possible to retrieve the Ulysses data within a few hours of a burst, generate an annulus of arrival directions, and e-mail it out to the astronomical community by local nightfall. Human operators remain in this loop, but we are developing a fully automated routine which should remove them, at least for intense events, and reduce turn-around times to an absolute minimum. We explain the current operations, the data types used, and the speed/accuracy tradeoffs

ANATOMY OF DEPLETED INTERPLANETARY CORONAL MASS EJECTIONS

Energy Technology Data Exchange (ETDEWEB)

Kocher, M.; Lepri, S. T.; Landi, E.; Zhao, L.; Manchester, W. B. IV, E-mail: mkocher@umich.edu [Department of Climate and Space Sciences and Engineering, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109-2143 (United States)

2017-01-10

We report a subset of interplanetary coronal mass ejections (ICMEs) containing distinct periods of anomalous heavy-ion charge state composition and peculiar ion thermal properties measured by ACE /SWICS from 1998 to 2011. We label them “depleted ICMEs,” identified by the presence of intervals where C{sup 6+}/C{sup 5+} and O{sup 7+}/O{sup 6+} depart from the direct correlation expected after their freeze-in heights. These anomalous intervals within the depleted ICMEs are referred to as “Depletion Regions.” We find that a depleted ICME would be indistinguishable from all other ICMEs in the absence of the Depletion Region, which has the defining property of significantly low abundances of fully charged species of helium, carbon, oxygen, and nitrogen. Similar anomalies in the slow solar wind were discussed by Zhao et al. We explore two possibilities for the source of the Depletion Region associated with magnetic reconnection in the tail of a CME, using CME simulations of the evolution of two Earth-bound CMEs described by Manchester et al.

Navajo Code Talker Joe Morris, Sr. shared insights from his time as a secret World War Two messenger

Science.gov (United States)

2002-01-01

Navajo Code Talker Joe Morris, Sr. shared insights from his time as a secret World War Two messenger with his audience at NASA's Dryden Flight Research Center on Nov. 26, 2002. NASA Dryden is located on Edwards Air Force Base in California's Mojave Desert.

The Acceleration of Thermal Protons and Minor Ions at a Quasi-Parallel Interplanetary Shock

Science.gov (United States)

Giacalone, J.; Lario, D.; Lepri, S. T.

2017-12-01

We compare the results from self-consistent hybrid simulations (kinetic ions, massless fluid electrons) and spacecraft observations of a strong, quasi-parallel interplanetary shock that crossed the Advanced Composition Explorer (ACE) on DOY 94, 2001. In our simulations, the un-shocked plasma-frame ion distributions are Maxwellian. Our simulations include protons and minor ions (alphas, 3He++, and C5+). The interplanetary shock crossed both the ACE and the Wind spacecraft, and was associated with significant increases in the flux of > 50 keV/nuc ions. Our simulation uses parameters (ion densities, magnetic field strength, Mach number, etc.) consistent with those observed. Acceleration of the ions by the shock, in a manner similar to that expected from diffusive shock acceleration theory, leads to a high-energy tail in the distribution of the post-shock plasma for all ions we considered. The simulated distributions are directly compared to those observed by ACE/SWICS, EPAM, and ULEIS, and Wind/STICS and 3DP, covering the energy range from below the thermal peak to the suprathermal tail. We conclude from our study that the solar wind is the most significant source of the high-energy ions for this event. Our results have important implications for the physics of the so-called `injection problem', which will be discussed.

Interplanetary radio storms. II - Emission levels and solar wind speed in the range 0.05-0.8 AU

Science.gov (United States)

Bougeret, J.-L.; Fainberg, J.; Stone, R. G.

1984-01-01

Storms of interplanetary type III radio bursts (IP storms) are commonly observed in the interplanetary medium by the ISEE-3 radio instrument. This instrument has the capability of accurately determining the arrival direction of the radio emission. At each observing frequency, the storm radio sources are tracked as they cross the line-of-sight to the sun. Using a simple model, the emission levels are determined at a number of radio frequencies for four separate storms. The IP storm radiation is found to occur in regions of enhanced density at levels of 0.05 to 0.8 AU. The density in these enhancements falls off faster than R(-2). The solar wind speed in the storm region is also measured. The analysis is consistent with steady conditions in the storm region during a few days around the III storm burst radio emission at the harmonic of the local plasma frequency.

Energy densities of Alfven waves between 0.7 and 1.6 AU. [in interplanetary medium

Science.gov (United States)

Belcher, J. W.; Burchsted, R.

1974-01-01

Plasma and field data from Mariner 4 and 5 between 0.7 and 1.6 AU are used to study the radial dependence of the levels of microscale fluctuation associated with interplanetary Alfven waves. The observed decrease of these levels with increasing distance from the sun is consistent with little or no local generation or damping of the ambient Alfven waves over this range of radial distance.

Messengers from outer space

International Nuclear Information System (INIS)

Jockers, K.

1981-01-01

In connection with the planned ESA space probe to Halley's Comet, a survey of our current knowledge of comets, and of open questions concerning them. The coma and the plasma and dust tail arise from the nucleus of the comet. Comets contain large amounts of water ice, and are surrounded by a gigantic cloud of hydrogen that is not visible to ground observation. The plasma tail arises by interaction with the solar wind. The cometary dust probably contains the most significant information on the origins of the solar system. Comets may contain prebiotic complex molecules. (orig.)

INTERPLANETARY MAGNETIC FLUX DEPLETION DURING PROTRACTED SOLAR MINIMA

International Nuclear Information System (INIS)

Connick, David E.; Smith, Charles W.; Schwadron, Nathan A.

2011-01-01

We examine near-Earth solar wind observations as assembled within the Omni data set over the past 15 years that constitute the latest solar cycle. We show that the interplanetary magnetic field continues to be depleted at low latitudes throughout the protracted solar minimum reaching levels below previously predicted minima. We obtain a rate of flux removal resulting in magnetic field reduction by 0.5 nT yr -1 at 1 AU when averaged over the years 2005-2009 that reduces to 0.3 nT yr -1 for 2007-2009. We show that the flux removal operates on field lines that follow the nominal Parker spiral orientation predicted for open field lines and are largely unassociated with recent ejecta. We argue that the field line reduction can only be accomplished by ongoing reconnection of nominally open field lines or very old closed field lines and we contend that these two interpretations are observationally equivalent and indistinguishable.

Langmuir waveforms at interplanetary shocks: STEREO statistical analysis

Science.gov (United States)

Briand, C.

2016-12-01

Wave-particle interactions and particle acceleration are the two main processes allowing energy dissipation at non collisional shocks. Ion acceleration has been deeply studied for many years, also for their central role in the shock front reformation. Electron dynamics is also important in the shock dynamics through the instabilities they can generate which may impact the ion dynamics.Particle measurements can be efficiently completed by wave measurements to determine the characteristics of the electron beams and study the turbulence of the medium. Electric waveforms obtained from the S/WAVES instrument of the STEREO mission between 2007 to 2014 are analyzed. Thus, clear signature of Langmuir waves are observed on 41 interplanetary shocks. These data enable a statistical analysis and to deduce some characteristics of the electron dynamics on different shocks sources (SIR or ICME) and types (quasi-perpendicular or quasi-parallel). The conversion process between electrostatic to electromagnetic waves has also been tested in several cases.

Mobile Probing and Probes

DEFF Research Database (Denmark)

Duvaa, Uffe; Ørngreen, Rikke; Weinkouff Mathiasen, Anne-Gitte

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...

Mobile Probing and Probes

DEFF Research Database (Denmark)

Duvaa, Uffe; Ørngreen, Rikke; Weinkouff, Anne-Gitte

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...

MESSENGER Spacecraft Phase Scintillation due to Plasma ductting effect on RF beam propagation at Superior Solar Conjunction

Science.gov (United States)

Mosavi, N.; Sequeira, H.; Copeland, D.; Menyuk, C.

2017-12-01

We investigate the evolution of a radio frequency (RF) X-band signal as it propagates through the solar corona turbulence in superior solar conjunction at low Sun-Earth-Probe (SEP) angles.Data that was obtained during several MESSENGER (MErcury Surface, Space ENivornment, GEochmeisty, and Ranging) conjunctions reveal a short-term and long-term effect. Amplitude scintillation is evident on a short time scale. Phase scintillations are stronger, but occur over a longer time scale. We examine different possible phenomena in the solar plasma that could be the source of the different time scales of the amplitude and phase scintillations. We propose a theoretical model in which the amplitude scintillations are due to local fluctuations of the index of refraction that scatter the RF signal. These rapidly varying fluctuations randomly attenuate the signal without affecting its phase. By contrast, we propose a model in which phase fluctuations are due to long ducts in the solar plasma, streaming from the sun, that trap some parts of the RF signal. These ducts act as waveguides, changing the phase velocity of the RF beam as it travels a zigzag path inside a duct. When the radiated wave exits from a duct, its phase is changed with respect to the signal that did not pass through the duct, which can lead to destructive interference and carrier suppression. The trapping of the wave is random in nature and can be either a fast or slow process. The predictions of this model are consistent with observations.

The evolution of Mercury's crust: a global perspective from MESSENGER.

Science.gov (United States)

Denevi, Brett W; Robinson, Mark S; Solomon, Sean C; Murchie, Scott L; Blewett, David T; Domingue, Deborah L; McCoy, Timothy J; Ernst, Carolyn M; Head, James W; Watters, Thomas R; Chabot, Nancy L

2009-05-01

Mapping the distribution and extent of major terrain types on a planet's surface helps to constrain the origin and evolution of its crust. Together, MESSENGER and Mariner 10 observations of Mercury now provide a near-global look at the planet, revealing lateral and vertical heterogeneities in the color and thus composition of Mercury's crust. Smooth plains cover approximately 40% of the surface, and evidence for the volcanic origin of large expanses of plains suggests that a substantial portion of the crust originated volcanically. A low-reflectance, relatively blue component affects at least 15% of the surface and is concentrated in crater and basin ejecta. Its spectral characteristics and likely origin at depth are consistent with its apparent excavation from a lower crust or upper mantle enriched in iron- and titanium-bearing oxides.

Stochastic diffusion of dust grains by the interplanetary magnetic field

International Nuclear Information System (INIS)

Hassan, M.H.A.; Wallis, M.K.

1983-10-01

The effects of the sectored Interplanetary Magnetic Field on charged dust grains orbiting around the sun under radiation pressure and Poynting-Robertson drag forces are examined for initially circular and non-inclined orbits. The distribution function of the charged grains satisfies a Fokker-Planck equation in which the sectored field is taken as a source of stochastic impulses. By adopting the integrals of the impulse-free motion as variable parameters, the Fokker-Planck equation can be properly treated as a diffusion equation. Analytic solutions of the resulting diffusion equation show that dust grains injected near the ecliptic plane are scattered strongly to high helio-latitudes. The scattering is more pronounced for small grains injected at large distances from the Sun. (author)

Interplanetary fast shock diagnosis with the radio receiver on Ulysses

Science.gov (United States)

Hoang, S.; Pantellini, F.; Harvey, C. C.; Lacombe, C.; Mangeney, A.; Meuer-Vernet, N.; Perche, C.; Steinberg, J.-L.; Lengyel-Frey, D.; Macdowall, R. J.

1992-01-01

The radio receiver on Ulysses records the quasi-thermal noise which allows a determination of the density and temperature of the cold (core) electrons of the solar wind. Seven interplanetary fast forward or reverse shocks are identified from the density and temperature profiles, together with the magnetic field profile from the Magnetometer experiment. Upstream of the three strongest shocks, bursts of nonthermal waves are observed at the electron plasma frequency f(peu). The more perpendicular the shock, the longer the time interval during which these upstream bursts are observed. For one of the strongest shocks we also observe two kinds of upstream electromagnetic radiation: radiation at 2 f(peu), and radiation at the downstream electron plasma frequency, which propagates into the less dense upstream regions.

Carbon Raman Spectroscopy of 36 Inter-Planetary Dust Particles

Science.gov (United States)

Busemann, H.; Nittler, L. R.; Davidson, J.; Franchi, I. A.; Messenger, S.; Nakamura-Messenger, K.; Palma, R. L.; Pepin, R. O.

2009-01-01

Carbon Raman spectroscopy is a useful tool to determine the degree of order of organic material (OM) in extra-terrestrial matter. As shown for meteoritic OM [e.g., 2], peak parameters of D and G bands are a measure of thermal alteration, causing graphitization (order), and amorphization, e.g. during protoplanetary irradiation, causing disorder. Th e most pristine interplanetary dust particles (IDPs) may come from comets. However, their exact provenance is unknown. IDP collection during Earth?s passage through comet Grigg-Skjellerup?s dust stream ("GSC" collectors) may increase the probability of collecting fresh IDPs from a known, cometary source. We used Raman spectroscopy to compare 21 GSC-IDPs with 15 IDPs collected at different periods, and found that the variation among GSC-IDPs is larger than among non-GSC IDPs, with the most primitive IDPs being mostly GSC-IDPs.

The F-region trough: seasonal morphology and relation to interplanetary magnetic field

Directory of Open Access Journals (Sweden)

M. Voiculescu

2006-03-01

Full Text Available We present here the results of a statistical study of the ionospheric trough observed in 2003 by means of satellite tomography. We focus on the seasonal morphology of the trough occurrence and investigate the trough latitude, width and the horizontal gradients at the edges, at different magnetic local times, as well as their relations to geomagnetic activity and the interplanetary magnetic field. A seasonal effect is noticed in the diurnal variation of the trough latitude, indicating that summer clearly differs from the other seasons. In winter the troughs seem to follow the solar terminator. The width of the trough has a diurnal variation and it depends on the season, as well. The broadest troughs are observed in winter and the narrowest ones in summer. A discontinuity in the diurnal variation of the trough latitude is observed before noon. It is suggested that this is an indication of a difference between the generation mechanisms of morningside and eveningside troughs. The density gradients at the edges have a complex dependence on the latitude of the trough and on geomagnetic activity. The photoionization and the auroral precipitation are competing in the formation of the trough walls at different magnetic local times. An important finding is that the interplanetary magnetic field plays a role in the occurrence of the trough at different levels of geomagnetic activity. This is probably associated with the topology of the polar cap convection pattern, which depends on the directions of the IMF components By and Bz.

The F-region trough: seasonal morphology and relation to interplanetary magnetic field

Directory of Open Access Journals (Sweden)

M. Voiculescu

2006-03-01

Full Text Available We present here the results of a statistical study of the ionospheric trough observed in 2003 by means of satellite tomography. We focus on the seasonal morphology of the trough occurrence and investigate the trough latitude, width and the horizontal gradients at the edges, at different magnetic local times, as well as their relations to geomagnetic activity and the interplanetary magnetic field. A seasonal effect is noticed in the diurnal variation of the trough latitude, indicating that summer clearly differs from the other seasons. In winter the troughs seem to follow the solar terminator. The width of the trough has a diurnal variation and it depends on the season, as well. The broadest troughs are observed in winter and the narrowest ones in summer. A discontinuity in the diurnal variation of the trough latitude is observed before noon. It is suggested that this is an indication of a difference between the generation mechanisms of morningside and eveningside troughs. The density gradients at the edges have a complex dependence on the latitude of the trough and on geomagnetic activity. The photoionization and the auroral precipitation are competing in the formation of the trough walls at different magnetic local times. An important finding is that the interplanetary magnetic field plays a role in the occurrence of the trough at different levels of geomagnetic activity. This is probably associated with the topology of the polar cap convection pattern, which depends on the directions of the IMF components B_y and B_z.

Interplanetary Magnetic Flux Ropes as Agents Connecting Solar Eruptions and Geomagnetic Activities

Science.gov (United States)

Marubashi, K.; Cho, K.-S.; Ishibashi, H.

2017-12-01

We investigate the solar wind structure for 11 cases that were selected for the campaign study promoted by the International Study of Earth-affecting Solar Transients (ISEST) MiniMax24 Working Group 4. We can identify clear flux rope signatures in nine cases. The geometries of the nine interplanetary magnetic flux ropes (IFRs) are examined with a model-fitting analysis with cylindrical and toroidal force-free flux rope models. For seven cases in which magnetic fields in the solar source regions were observed, we compare the IFR geometries with magnetic structures in their solar source regions. As a result, we can confirm the coincidence between the IFR orientation and the orientation of the magnetic polarity inversion line (PIL) for six cases, as well as the so-called helicity rule as regards the handedness of the magnetic chirality of the IFR, depending on which hemisphere of the Sun the IFR originated from, the northern or southern hemisphere; namely, the IFR has right-handed (left-handed) magnetic chirality when it is formed in the southern (northern) hemisphere of the Sun. The relationship between the orientation of IFRs and PILs can be taken as evidence that the flux rope structure created in the corona is in most cases carried through interplanetary space with its orientation maintained. In order to predict magnetic field variations on Earth from observations of solar eruptions, further studies are needed about the propagation of IFRs because magnetic fields observed at Earth significantly change depending on which part of the IFR hits the Earth.

Preparation, analysis, and release of simulated interplanetary grains into low earth orbit

International Nuclear Information System (INIS)

Stephens, J.R.; Strong, I.B.; Kunkle, T.D.

1985-01-01

Astronomical observations which reflect the optical and dynamical properties of interstellar and interplanetary grains are the primary means of identifying the shape, size, and the chemistry of extraterrestrial grain materials and is a major subject of this workshop. Except for recent samplings of extraterrestrial particles in near-Earth orbit and in the stratosphere, observations have been the only method of deducing the properties of extraterrestrial particles. Terrestrial laboratory experiments typically seek not to reproduce astrophysical conditions but to illuminate fundamental dust processes and properties which must be extrapolated to interesting astrophysical conditions. In this report, we discuss the formation and optical characterization of simulated interstellar and interplanetary dust with particular emphasis on studying the properties on irregularly shaped particles. We also discuss efforts to develop the techniques to allow dust experiments to be carried out in low-Earth orbit, thus extending the conditions under which dust experiments may be performed. The objectives of this study are threefold: (1) Elucidate the optical properties, including scattering and absorption, of simulated interstellar grains including SiC, silicates, and carbon grains produced in the laboratory. (2) Develop the capabilities to release grains and volatile materials into the near-Earth environment and study their dynamics and optical properties. (3) Study the interaction of released materials with the near-Earth environment to elucidate grain behavior in astrophysical environments. Interaction of grains with their environment may, for example, lead to grain alignment or coagulation, which results in observable phenomena such as polarization of lighter or a change of the scattering properties of the grains

Ubiquitous learning model using interactive internet messenger group (IIMG) to improve engagement and behavior for smart campus

Science.gov (United States)

Umam, K.; Mardi, S. N. S.; Hariadi, M.

2017-01-01

The recent popularity of internet messenger based smartphone technologies has motivated some university lecturers to use them for educational activities. These technologies have enormous potential to enhance the teaching and ubiquitous learning experience for smart campus development. However, the design ubiquitous learning model using interactive internet messenger group (IIMG) and empirical evidence that would favor a broad application of mobile and ubiquitous learning in smart campus settings to improve engagement and behavior is still limited. In addition, the expectation that mobile learning could improve engagement and behavior on smart campus cannot be confirmed because the majority of the reviewed studies followed instructions paradigms. This article aims to present ubiquitous learning model design and showing learners’ experiences in improved engagement and behavior using IIMG for learner-learner and learner-lecturer interactions. The method applied in this paper includes design process and quantitative analysis techniques, with the purpose of identifying scenarios of ubiquitous learning and realize the impressions of learners and lecturers about engagement and behavior aspect, and its contribution to learning.

Affleck-Dine baryogenesis, condensate fragmentation and gravitino dark matter in gauge-mediation with a large messenger mass

International Nuclear Information System (INIS)

Doddato, Francesca; McDonald, John

2011-01-01

We study the conditions for successful Affleck-Dine baryogenesis and the origin of gravitino dark matter in GMSB models. AD baryogenesis in GMSB models is ruled out by neutron star stability unless Q-balls are unstable and decay before nucleosynthesis. Unstable Q-balls can form if the messenger mass scale is larger than the flat-direction field Φ when the condensate fragments. We provide an example based on AD baryogenesis along a d = 6 flat direction for the case where m 3/2 ≈ 2GeV, as predicted by gravitino dark matter from Q-ball decay. Using a phenomenological GMSB potential which models the Φ dependence of the SUSY breaking terms, we numerically solve for the evolution of Φ and show that the messenger mass can be sufficiently close to the flat-direction field when the condensate fragments. We compute the corresponding reheating temperature and the baryonic charge of the condensate fragments and show that the charge is large enough to produce late-decaying Q-balls which can be the origin of gravitino dark matter

A review of planetary and space science projects presented at iCubeSat, the Interplanetary CubeSat Workshop

Science.gov (United States)

Johnson, Michael

2015-04-01

iCubeSat, the Interplanetary CubeSat Workshop, is an annual technical workshop for researchers working on an exciting new standardised platform and opportunity for planetary and space scientists. The first workshop was held in 2012 at MIT, 2013 at Cornell, 2014 at Caltech with the 2015 workshop scheduled to take place on the 26-27th May 2015 at Imperial College London. Mission concepts and flight projects presented since 2012 have included orbiters and landers targeting asteroids, the moon, Mars, Venus, Saturn and their satellites to perform science traditionally reserved for flagship missions at a fraction of their cost. Some of the first missions proposed are currently being readied for flight in Europe, taking advantage of multiple ride share launch opportunities and technology providers. A review of these and other interplanetary CubeSat projects will be presented, covering details of their science objectives, instrument capabilities, technology, team composition, budget, funding sources, and the other programattic elements required to implement this potentially revolutionary new class of mission.

Cyclic [G(2',5')pA(3',5')p] is the metazoan second messenger produced by DNA-activated cyclic GMP-AMP synthase.

Science.gov (United States)

Gao, Pu; Ascano, Manuel; Wu, Yang; Barchet, Winfried; Gaffney, Barbara L; Zillinger, Thomas; Serganov, Artem A; Liu, Yizhou; Jones, Roger A; Hartmann, Gunther; Tuschl, Thomas; Patel, Dinshaw J

2013-05-23

Recent studies identified cyclic GMP-AMP (cGAMP) as a metazoan second messenger triggering an interferon response. cGAMP is generated from GTP and ATP by cytoplasmic dsDNA sensor cGAMP synthase (cGAS). We combined structural, chemical, biochemical, and cellular assays to demonstrate that this second messenger contains G(2',5')pA and A(3',5')pG phosphodiester linkages, designated c[G(2',5')pA(3',5')p]. We show that, upon dsDNA binding, cGAS is activated through conformational transitions, resulting in formation of a catalytically competent and accessible nucleotide-binding pocket for generation of c[G(2',5')pA(3',5')p]. We demonstrate that cyclization occurs in a stepwise manner through initial generation of 5'-pppG(2',5')pA prior to cyclization to c[G(2',5')pA(3',5')p], with the latter positioned precisely in the catalytic pocket. Mutants of cGAS dsDNA-binding or catalytic pocket residues exhibit reduced or abrogated activity. Our studies have identified c[G(2',5')pA(3',5')p] as a founding member of a family of metazoan 2',5'-containing cyclic heterodinucleotide second messengers distinct from bacterial 3',5' cyclic dinucleotides. Copyright © 2013 Elsevier Inc. All rights reserved.

Magnetic superstorm on August 4-5, 1972 in connection with a hydromagnetic structure of the interplanetary plasma stream from a powerful flare

International Nuclear Information System (INIS)

Ivanov, K.G.; Mikerina, N.V.

1977-01-01

A comparison is made between the hydromagnetic structure of the interplanetary plasma flux from the powerful solar flare occurred on 4.08.1972 and the magnetic storm of 4-5.08.1972. The geomagnetic effects of the head impact layer of the interplanetary flux are being considered. The world-wide disturbances being most intensive in the Polar regions corresponded to the elements of the substructure of the impact layer. These disturbances are interpreted as the superposition of magnetic fields from reconnection currents on the magnetopause and in the neutral layer of the magnetosphere trail. The qualitative description of the effects under investigation has been made on the assumption that the magnetopause is a rotational impact wave

Strong geomagnetic activity forecast by neural networks under dominant southern orientation of the interplanetary magnetic field

Czech Academy of Sciences Publication Activity Database

Valach, F.; Bochníček, Josef; Hejda, Pavel; Revallo, M.

2014-01-01

Roč. 53, č. 4 (2014), s. 589-598 ISSN 0273-1177 R&D Projects: GA AV ČR(CZ) IAA300120608; GA MŠk OC09070 Institutional support: RVO:67985530 Keywords : geomagnetic activity * interplanetary magnetic field * artificial neural network * ejection of coronal mass * X-ray flares Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.358, year: 2014

The Effects of Interplanetary Transport in the Event-intergrated Solar Energetic Particle Spectra

Energy Technology Data Exchange (ETDEWEB)

Zhao, Lulu; Zhang, Ming; Rassoul, Hamid K., E-mail: lzhao@fit.edu [Physics and Space Sciences Department, Florida Institute of Technology, Melbourne, FL 32901 (United States)

2017-02-10

Previous investigations on the energy spectra of solar energetic particle (SEP) events revealed that the energy spectra observed at 1 au often show double power laws with break energies from one to tens of MeV/nuc. In order to determine whether the double power-law features result from the SEP source or the interplanetary transport process from the Sun to 1 au, we separately analyze the SEP spectra in the decay phase, during which the transport effect is minimum. In this paper, we reported three events observed by the Interplanetary Monitory Platform 8 spacecraft, which occurred on 1977 September 19, November 22, and 1979 March 1. For the first two events, the event-integrated spectra of protons possess double power-law profiles with break energies in a range of several MeV to tens of MeV, while the spectra integrated in the decay (reservoir) phase yield single power laws. Moreover, a general trend from a double power law at the rising phase to a single power law at the decay phase is observed. For the third event, both the event-integrated and the reservoir spectra show double power-law features. However, the difference between the low- and high-energy power-law indices is smaller for the reservoir spectrum than the event-integrated spectrum. These features were reproduced by solving the 1D diffusion equation analytically and we suggest that the transport process, especially the diffusion process, plays an important role in breaking the energy spectra.

Van Allen Probes, THEMIS, GOES, and Cluster Observations of EMIC Waves, ULF Pulsations, and an Electron Flux Dropout

Science.gov (United States)

Sigsbee, K.; Kletzing, C. A.; Smith, C. W.; Macdowall, R.; Spence, H.; Reeves, G.; Blake, J. B.; Baker, D. N.; Green, J. C.; Singer, H. J.;

Using Pre-melted Phase Change Material to Keep Payload Warm without Power for Hours in Space

Science.gov (United States)

Choi, Michael K.

2012-01-01

During a payload transition from the transport vehicle to its worksite on the International Space Station (ISS), the payload is unpowered for up to 6 hours. Its radiator(s) will continue to radiate heat to space. It is necessary to make up the heat loss to maintain the payload temperature above the cold survival limit. Typically an interplanetary Probe has no power generation system. It relies on its battery to provide limited power for the Communication and Data Handling (C&DH) subsystem during cruise, and heater power is unavailable. It is necessary to maintain the C&DH temperature above the minimum operating limit. This paper presents a novel thermal design concept that utilizes phase change material (PCM) to store thermal energy by melting it before the payload or interplanetary Probe is unpowered. For the ISS, the PCM is melted by heaters just prior to the payload transition from the transport vehicle to its worksite. For an interplanetary Probe, the PCM is melted by heaters just prior to separation from the orbiter. The PCM releases thermal energy to keep the payload warm for several hours after power is cut off.

Gravity field and internal structure of Mercury from MESSENGER.

Science.gov (United States)

Smith, David E; Zuber, Maria T; Phillips, Roger J; Solomon, Sean C; Hauck, Steven A; Lemoine, Frank G; Mazarico, Erwan; Neumann, Gregory A; Peale, Stanton J; Margot, Jean-Luc; Johnson, Catherine L; Torrence, Mark H; Perry, Mark E; Rowlands, David D; Goossens, Sander; Head, James W; Taylor, Anthony H

2012-04-13

Radio tracking of the MESSENGER spacecraft has provided a model of Mercury's gravity field. In the northern hemisphere, several large gravity anomalies, including candidate mass concentrations (mascons), exceed 100 milli-Galileos (mgal). Mercury's northern hemisphere crust is thicker at low latitudes and thinner in the polar region and shows evidence for thinning beneath some impact basins. The low-degree gravity field, combined with planetary spin parameters, yields the moment of inertia C/MR(2) = 0.353 ± 0.017, where M and R are Mercury's mass and radius, and a ratio of the moment of inertia of Mercury's solid outer shell to that of the planet of C(m)/C = 0.452 ± 0.035. A model for Mercury's radial density distribution consistent with these results includes a solid silicate crust and mantle overlying a solid iron-sulfide layer and an iron-rich liquid outer core and perhaps a solid inner core.

Gravity Field and Internal Structure of Mercury from MESSENGER

Science.gov (United States)

Smith, David E.; Zuber, Maria T.; Phillips, Roger J.; Solomon, Sean C.; Hauck, Steven A., II; Lemoine, Frank G.; Mazarico, Erwan; Neumann, Gregory A.; Peale, Stanton J.; Margot, Jean-Luc;

Relationship of upflowing ion beams and conics around the dayside cusp/cleft region to the interplanetary conditions

Directory of Open Access Journals (Sweden)

W. Miyake

2002-04-01

Full Text Available The dayside cusp/cleft region is known as a major source of upflowing ionospheric ions to the magnetosphere. Since the ions are supposed to be energized by an input of energy from the dayside magnetospheric boundary region, we examined the possible influence of the interplanetary conditions on dayside ion beams and conics observed by the polar-orbiting Exos-D (Akebono satellite. We found that both the solar wind velocity and density, as well as IMF By and Bz , affect the occurrence frequency of ion conics. The energy of ion conics also depends on the solar wind velocity, IMF By and Bz . The ion beams around the local noon are not significantly controlled by the interplanetary conditions. The results reveal that ion convection, as well as the energy source, is important to understand the production of dayside ion conics while that of ion beams basically reflects the intensity of local field-aligned currents.Key words. Ionosphere (particle acceleration – magnetospheric physics (magnetopause, cusp, and boundary layers; magnetosphere ionosphere interaction

High-latitude dayside electric fields and currents during strong northward interplanetary magnetic field: Observations and model simulation

International Nuclear Information System (INIS)

Clauer, C.R.; Friis-Christensen, E.

1988-01-01

On July 23, 1983, the Interplanetary Magnetic Field turned strongly northward, becoming about 22 nT for several hours. Using a combined data set of ionospheric convection measurements made by the Sondre Stromfjord incoherent scatter radar and convection inferred from Greenland magnetometer measurements, we observe the onset of the reconfiguration of the high-latitude ionospheric currents to occur about 3 min following the northward IMF encountering the magnetopause. The large-scale reconfiguration of currents, however, appears to evolve over a period of about 22 min. Using a computer model in which the distribution of field-aligned current in the polar cleft is directly determined by the strength and orientation of the interplanetary electric field, we are able to simulate the time-varying pattern of ionospheric convection, including the onset of high-latitude ''reversed convection'' cells observed to form during the interval of strong northward IMF. These observations and the simulation results indicate that the dayside polar cap electric field observed during strong northward IMF is produced by a direct electrical current coupling with the solar wind. copyright American Geophysical Union 1988

Mercury's Seasonal Sodium Exosphere: MESSENGER Orbital Observations

Science.gov (United States)

Cassidy, Timothy A.; Merkel, Aimee W.; Burger, Matthew H.; Killen, Rosemary M.; McClintock, William E.; Vervack, Ronald J., Jr.; Sarantos, Menelaos

2014-01-01

The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) Ultraviolet and Visible Spectrometer (UVVS) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft now orbiting Mercury provides the first close-up look at the planet's sodium exosphere. UVVS has observed the exosphere from orbit almost daily for over 10 Mercury years. In this paper we describe and analyze a subset of these data: altitude profiles taken above the low-latitude dayside and south pole. The observations show spatial and temporal variations, but there are no obvious year-to-year variations in most of the observations. We do not see the episodic variability reported by some ground-based observers. We used these altitude profiles to make estimates of sodium density and temperature. The bulk of the exosphere, at about 1200 K, is much warmer than Mercury's surface. This value is consistent with some ground-based measurements and suggests that photon-stimulated desorption is the primary ejection process. We also observe a tenuous energetic component but do not see evidence of the predicted thermalized (or partially thermalized) sodium near Mercury's surface temperature. Overall we do not see the variable mixture of temperatures predicted by most Monte Carlo models of the exosphere.

The Future of Geomagnetic Storm Predictions: Implications from Recent Solar and Interplanetary Observations

Science.gov (United States)

Tsurutani, B. T.; Gonzalez, W. D.

1995-01-01

Within the last 7-8 years, there has been a substantial growth in out knowledge of the solar and interplanetary causes of geomagnetic storms at Earth. This review article will not attempt to cover all of the work done during this period. This can be found elsewhere. Our emphasis here will be on recent efforts that expose important, presently unanswered questions that must be addressed and solved before true predictability of storms can be possible. Hopefully, this article will encourage some readers to join this effort and perhaps make major contributions to the field.

Estimating random transverse velocities in the fast solar wind from EISCAT Interplanetary Scintillation measurements

Directory of Open Access Journals (Sweden)

A. Canals

2002-09-01

Full Text Available Interplanetary scintillation measurements can yield estimates of a large number of solar wind parameters, including bulk flow speed, variation in bulk velocity along the observing path through the solar wind and random variation in transverse velocity. This last parameter is of particular interest, as it can indicate the flux of low-frequency Alfvén waves, and the dissipation of these waves has been proposed as an acceleration mechanism for the fast solar wind. Analysis of IPS data is, however, a significantly unresolved problem and a variety of a priori assumptions must be made in interpreting the data. Furthermore, the results may be affected by the physical structure of the radio source and by variations in the solar wind along the scintillation ray path. We have used observations of simple point-like radio sources made with EISCAT between 1994 and 1998 to obtain estimates of random transverse velocity in the fast solar wind. The results obtained with various a priori assumptions made in the analysis are compared, and we hope thereby to be able to provide some indication of the reliability of our estimates of random transverse velocity and the variation of this parameter with distance from the Sun.Key words. Interplanetary physics (MHD waves and turbulence; solar wind plasma; instruments and techniques

Estimating random transverse velocities in the fast solar wind from EISCAT Interplanetary Scintillation measurements

Directory of Open Access Journals (Sweden)

A. Canals

Full Text Available Interplanetary scintillation measurements can yield estimates of a large number of solar wind parameters, including bulk flow speed, variation in bulk velocity along the observing path through the solar wind and random variation in transverse velocity. This last parameter is of particular interest, as it can indicate the flux of low-frequency Alfvén waves, and the dissipation of these waves has been proposed as an acceleration mechanism for the fast solar wind. Analysis of IPS data is, however, a significantly unresolved problem and a variety of a priori assumptions must be made in interpreting the data. Furthermore, the results may be affected by the physical structure of the radio source and by variations in the solar wind along the scintillation ray path. We have used observations of simple point-like radio sources made with EISCAT between 1994 and 1998 to obtain estimates of random transverse velocity in the fast solar wind. The results obtained with various a priori assumptions made in the analysis are compared, and we hope thereby to be able to provide some indication of the reliability of our estimates of random transverse velocity and the variation of this parameter with distance from the Sun.

Key words. Interplanetary physics (MHD waves and turbulence; solar wind plasma; instruments and techniques

Optimizing interplanetary trajectories with deep space maneuvers

Science.gov (United States)

Navagh, John

1993-09-01

Analysis of interplanetary trajectories is a crucial area for both manned and unmanned missions of the Space Exploration Initiative. A deep space maneuver (DSM) can improve a trajectory in much the same way as a planetary swingby. However, instead of using a gravitational field to alter the trajectory, the on-board propulsion system of the spacecraft is used when the vehicle is not near a planet. The purpose is to develop an algorithm to determine where and when to use deep space maneuvers to reduce the cost of a trajectory. The approach taken to solve this problem uses primer vector theory in combination with a non-linear optimizing program to minimize Delta(V). A set of necessary conditions on the primer vector is shown to indicate whether a deep space maneuver will be beneficial. Deep space maneuvers are applied to a round trip mission to Mars to determine their effect on the launch opportunities. Other studies which were performed include cycler trajectories and Mars mission abort scenarios. It was found that the software developed was able to locate quickly DSM's which lower the total Delta(V) on these trajectories.

The jabber chat tool EFDA Messenger and screen sharing tool EFDATV

Energy Technology Data Exchange (ETDEWEB)

Thomsen, K. [EFDA Close Support Unit Garching, Boltzmannstr. 2, D-85748 Garching (Germany)], E-mail: Knud.Thomsen@efda.org; Beck, S. [EFDA Close Support Unit Garching, Boltzmannstr. 2, D-85748 Garching (Germany); Wilhelm, B. [EFDA CSU Barcelona, c/Josep Pla n.2, Torres Diag. Litoral Edificio B3, 7a planta, 08019 Barcelona (Spain)

2008-04-15

Two Remote Participation (RP) tools are described. The first tool, named EFDA Messenger, is a secure Instant Messaging (IM) tool based on a Jabber server that only accepts SSL encrypted communication and does not allow file transfers as well as audio and video transmissions. This tool is useful to have as another mean of communication during video or teleconferences. The second tool, named EFDATV, is a multipurposeVirtual Network Computing (VNC) based desktop screen sharing system used to share presentations via the Internet. A Java enabled web browser or a VNC client is sufficient for the presenter and the audience to use EFDATV. It is also possible from an EFDATV channel to connect to another VNC server and broadcast the view from that VNC server.

The jabber chat tool EFDA Messenger and screen sharing tool EFDATV

International Nuclear Information System (INIS)

Thomsen, K.; Beck, S.; Wilhelm, B.

2008-01-01

Two Remote Participation (RP) tools are described. The first tool, named EFDA Messenger, is a secure Instant Messaging (IM) tool based on a Jabber server that only accepts SSL encrypted communication and does not allow file transfers as well as audio and video transmissions. This tool is useful to have as another mean of communication during video or teleconferences. The second tool, named EFDATV, is a multipurposeVirtual Network Computing (VNC) based desktop screen sharing system used to share presentations via the Internet. A Java enabled web browser or a VNC client is sufficient for the presenter and the audience to use EFDATV. It is also possible from an EFDATV channel to connect to another VNC server and broadcast the view from that VNC server

Postage for the messenger: Designating routes for Nuclear mRNA Export

Science.gov (United States)

Natalizio, Barbara J.; Wente, Susan R.

2013-01-01

Transcription of messenger(m) RNA occurs in the nucleus, making the translocation of mRNA across the nuclear envelope (NE) boundary a critical determinant of proper gene expression and cell survival. A major mRNA export route occurs via the NXF1-dependent pathway through the nuclear pore complexes (NPCs) embedded in the NE. However, recent findings have discovered new evidence supporting the existence of multiple mechanisms for crossing the NE, including both NPC-mediated and NE budding-mediated pathways. An analysis of the trans-acting factors and cis components that define these pathways reveals shared elements as well as mechanistic differences. We review here the current understanding of the mechanisms that characterize each pathway and highlight the determinants that influence mRNA transport fate. PMID:23583578

Two-dimensional, time-dependent MHD description of interplanetary disturbances: simulation of high speed solar wind interactions

International Nuclear Information System (INIS)

Wu, S.T.; Han, S.M.; Dryer, M.

1979-01-01

A two-dimensional, time-dependent, magnetohydrodynamic, numerical model is used to investigate multiple, transient solar wind flows which start close to the Sun and then extend into interplanetary space. The initial conditions are assumed to be appropriate for steady, homogeneous solar wind conditions with an average, spiral magnetic field configuration. Because both radial and azimuthal dimensions are included, it is possible to place two or more temporally-developing streams side-by-side at the same time. Thus, the evolution of the ensuing stream interaction is simulated by this numerical code. Advantages of the present method are as follows: (1) the development and decay of asymmetric MHD shocks and their interactions are clearly indicated; and (2) the model allows flexibility in the specification of evolutionary initial conditions in the azimuthal direction, thereby making it possible to gain insight concerning the interplanetary consequences of real physical situations more accurately than by use of the one-dimensional approach. Examples of such situations are the occurrence of near-simultaneous solar flares in adjacent active regions and the sudden appearance of enlargement of coronal holes as a result of a transient re-arrangement from a closed to an open magnetic field topology. (author)

Use of Faraday-rotation data from beacon satellites to determine ionospheric corrections for interplanetary spacecraft navigation

Science.gov (United States)

Royden, H. N.; Green, D. W.; Walson, G. R.

1981-01-01

Faraday-rotation data from the linearly polarized 137-MHz beacons of the ATS-1, SIRIO, and Kiku-2 geosynchronous satellites are used to determine the ionospheric corrections to the range and Doppler data for interplanetary spacecraft navigation. The JPL operates the Deep Space Network of tracking stations for NASA; these stations monitor Faraday rotation with dual orthogonal, linearly polarized antennas, Teledyne polarization tracking receivers, analog-to-digital converter/scanners, and other support equipment. Computer software examines the Faraday data, resolves the pi ambiguities, constructs a continuous Faraday-rotation profile and converts the profile to columnar zenith total electron content at the ionospheric reference point; a second program computes the line-of-sight ionospheric correction for each pass of the spacecraft over each tracking complex. Line-of-sight ionospheric electron content using mapped Faraday-rotation data is compared with that using dispersive Doppler data from the Voyager spacecraft; a difference of about 0.4 meters, or 5 x 10 to the 16th electrons/sq m is obtained. The technique of determining the electron content of interplanetary plasma by subtraction of the ionospheric contribution is demonstrated on the plasma torus surrounding the orbit of Io.

Interplanetary sector boundaries 1971--1973

International Nuclear Information System (INIS)

Klein, L.; Burlaga, L.F.

1980-01-01

Eighteen interplanetary sector boundary crossings observed at 1 AU during the period January 1971 to January 1974 by the magnetometer on the Imp 6 spacecraft was discussed. The events were examined on many different time scales ranging from days on either side of the boundary to high-resolution measurements of 12.5 vectors per second. Two categories of boundaries were found, one group being relatively thin (averaging approx. =10 4 km) and the other being thick (averaging approx. =10 6 km). In many cases the field vector rotated in a plane from polarity to the other. Only two of the transitions were null sheets. Using the minimum variance analysis to determine the normals to the plane of rotationa and assuming that this is the same as the normal to the sector boundary surface, it was found that the normals were close to ( 0 ) the ecliptic plane. The high inclination of the sector boundary surfaces during 1971--1973 verifies a published prediction and may be related to the presence of large equatorial coronal holes at this time. An analysis of tangential discontinuities contained in 4-day periods about our events showed that their orientations were generally not related to the orientations of the sector boundary surface, but rather their characteristics were about the same as those for discontinuities outside the sector boundaries. Magnetic holes were found in thick sector boundaries, at a rate about 3 times that elsewhere. The holes were especially prevalent near stream interfaces, suggesting that they might be related to the convergence and/or slip of adjacent solar wind streams

HIGH-RESOLUTION TOPOGRAPHY OF MERCURY FROM MESSENGER ORBITAL STEREO IMAGING – THE SOUTHERN HEMISPHERE QUADRANGLES

Directory of Open Access Journals (Sweden)

F. Preusker

2018-04-01

Full Text Available We produce high-resolution (222 m/grid element Digital Terrain Models (DTMs for Mercury using stereo images from the MESSENGER orbital mission. We have developed a scheme to process large numbers, typically more than 6000, images by photogrammetric techniques, which include, multiple image matching, pyramid strategy, and bundle block adjustments. In this paper, we present models for map quadrangles of the southern hemisphere H11, H12, H13, and H14.

Modeling of the Magnetosphere of Mercury at the Time of the First MESSENGER Flyby

Science.gov (United States)

Benna, Mehdi; Anderson, Brian J.; Baker, Daniel N.; Boardsen, Scott A.; Gloeckler, George; Gold, Robert E.; Ho, George C.; Killen, Rosemary M.; Korth, Haje; Krimigis, Stamatios M.;

Oxygen Isotopes in Chondritic Interplanetary Dust: Parent-Bodies and Nebular Oxygen Reservoirs

International Nuclear Information System (INIS)

Aleon, J; McKeegan, K D; Leshin, L

2006-01-01

Planetary objects have preserved various amounts of oxygen issued from isotopically different oxygen reservoirs reflecting their origin and physico-chemical history. An 16 O-rich component is preserved in refractory inclusions (CAIs) whereas meteorites matrices are enriched in an 16 O-poor component. The origin of these components is still unclear. The most recent models are based on isotope selective photodissociation of CO in a 16 O-rich nebula/presolr cloud resulting in a 16 O-poor gas in the outer part of the nebula. However because most meteorite components are thought to be formed in the inner 3AU of the solar nebula, the precise isotopic composition of outer solar system components is yet unknown. In that respect, the oxygen isotopic composition of cometary dust is a key to understand the origin of the solar system. The Stardust mission will bring back to the Earth dust samples from comet Wild2, a short period comet from the Jupiter family. A precise determination of the oxygen isotope composition of Wild2 dust grains is essential to decipher the oxygen reservoirs of the outer solar system. However, Stardust samples may be extremely fragmented upon impact in the collector. In addition, interplanetary dust particles (IDPs) collected in the stratosphere are likely to contain comet samples. Therefore, they started to investigate the oxygen isotopic composition of a suite of chondritic interplanetary dust particles that includes IDPs of potential cometary origin using a refined procedure to increase the lateral resolution for the analysis of Stardust grains or IDP subcomponents down to ∼ 3 (micro)m. High precision data for 4 IDPs were previously reported, here they have measured 6 additional IDPs

WhatsApp Messenger as a Learning Tool: An Investigation of Pre-Service Teachers' Learning without Instructor Presence

Science.gov (United States)

Alenazi, Ali A.

2018-01-01

This study investigated the extent to which pre-service teachers can utilize WhatsApp Messenger to create an effective learning platform without instructor interference. Twenty-six male pre-service teachers created a WhatsApp group and interacted through it independently for nine weeks. Each pre-service teacher was required to share a minimum of…

The Effectiveness of Using WhatsApp Messenger as One of Mobile Learning Techniques to Develop Students' Writing Skills

Science.gov (United States)

Fattah, Said Fathy El Said Abdul

2015-01-01

The present study was an attempt to determine the effectiveness of using a WhatsApp Messenger as one of mobile learning techniques to develop students' writing skills. Participants were 30 second year college students, English department from a private university in Saudi Arabia. The experimental group (N = 15) used WhatsApp technology to develop…

A theoretical perspective on particle acceleration by interplanetary shocks and the Solar Energetic Particle problem

Energy Technology Data Exchange (ETDEWEB)

Verkhoglyadova, Olga P. [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL35899 (United States); Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA91109 (United States); Zank, Gary P.; Li, Gang [Department of Space Science, UAH, Huntsville, AL35899 (United States); Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL35899 (United States)

2015-02-12

Understanding the physics of Solar Energetic Particle (SEP) events is of importance to the general question of particle energization throughout the cosmos as well as playing a role in the technologically critical impact of space weather on society. The largest, and often most damaging, events are the so-called gradual SEP events, generally associated with shock waves driven by coronal mass ejections (CMEs). We review the current state of knowledge about particle acceleration at evolving interplanetary shocks with application to SEP events that occur in the inner heliosphere. Starting with a brief outline of recent theoretical progress in the field, we focus on current observational evidence that challenges conventional models of SEP events, including complex particle energy spectra, the blurring of the distinction between gradual and impulsive events, and the difference inherent in particle acceleration at quasi-parallel and quasi-perpendicular shocks. We also review the important problem of the seed particle population and its injection into particle acceleration at a shock. We begin by discussing the properties and characteristics of non-relativistic interplanetary shocks, from their formation close to the Sun to subsequent evolution through the inner heliosphere. The association of gradual SEP events with shocks is discussed. Several approaches to the energization of particles have been proposed, including shock drift acceleration, diffusive shock acceleration (DSA), acceleration by large-scale compression regions, acceleration by random velocity fluctuations (sometimes known as the “pump mechanism”), and others. We review these various mechanisms briefly and focus on the DSA mechanism. Much of our emphasis will be on our current understanding of the parallel and perpendicular diffusion coefficients for energetic particles and models of plasma turbulence in the vicinity of the shock. Because of its importance both to the DSA mechanism itself and to the

A new methodology of second messenger imaging for higher cortical functions by positron emission tomography

International Nuclear Information System (INIS)

Imahori, Yoshio; Ueda, Satoshi

1992-01-01

Neuronal manifestations are driven by second messenger systems in central nervous system through the neuronal transmission process. Receptor-mediated phosphatidylinositol (PI) response images may reflect neuronal activation in higher cortical function with a high sensitivity based on the common amplifying mechanism of the second messenger. Many bioactive compounds related to PI turnover have simple carbohydrate structures without amines and [ 11 C]ethylketene acylation has been found as the most effective labeling method of these compounds for positron emission tomography. [ 11 C]ethylketene was produced by the pyrolytic decomposition of [1- 11 C]butyric acid. This new method was made possible by the reaction under the no-carrier-added condition. To visualize the response in vivo, we synthesized sn-1,2-[ 11 C]diacylglycerols (DAGs) as a specific tracer for the PI response and [ 11 C]phorbol esters as a ligand for protein kinase C. In autoradiographic studies it was demonstrated that sn-1,2-[ 11 C]DAGs incorporation sites were discretely localized especially in the neocortex, which were concomitant with columnar structures. These results suggested that sn-1,2-[ 11 C]DAG can serve as an extrinsic substrate for the PI turnover by the phosphorylation mechanism and intensive neuronal processing, as a higher cortical function, occurs in these areas on the basis of receptor-mediated PI response. (author)

Plasma Distribution in Mercury's Magnetosphere Derived from MESSENGER Magnetometer and Fast Imaging Plasma Spectrometer Observations

Science.gov (United States)

Korth, Haje; Anderson, Brian J.; Gershman, Daniel J.; Raines, Jim M.; Slavin, James A.; Zurbuchen, Thomas H.; Solomon, Sean C.; McNutt, Ralph L.

2014-01-01

We assess the statistical spatial distribution of plasma in Mercury's magnetosphere from observations of magnetic pressure deficits and plasma characteristics by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. The statistical distributions of proton flux and pressure were derived from 10months of Fast Imaging Plasma Spectrometer (FIPS) observations obtained during the orbital phase of the MESSENGER mission. The Magnetometer-derived pressure distributions compare favorably with those deduced from the FIPS observations at locations where depressions in the magnetic field associated with the presence of enhanced plasma pressures are discernible in the Magnetometer data. The magnitudes of the magnetic pressure deficit and the plasma pressure agree on average, although the two measures of plasma pressure may deviate for individual events by as much as a factor of approximately 3. The FIPS distributions provide better statistics in regions where the plasma is more tenuous and reveal an enhanced plasma population near the magnetopause flanks resulting from direct entry of magnetosheath plasma into the low-latitude boundary layer of the magnetosphere. The plasma observations also exhibit a pronounced north-south asymmetry on the nightside, with markedly lower fluxes at low altitudes in the northern hemisphere than at higher altitudes in the south on the same field line. This asymmetry is consistent with particle loss to the southern hemisphere surface during bounce motion in Mercury's offset dipole magnetic field.

14 July 2000, a near-global coronal event and its association with energetic electron events detected in the interplanetary medium

Czech Academy of Sciences Publication Activity Database

Maia, D.; Pick, M.; Hawkins, S. E.; Fomichev, V. V.; Jiřička, Karel

2001-01-01

Roč. 204, 1/2 (2001), s. 199-214 ISSN 0038-0938 Institutional research plan: CEZ:AV0Z1003909 Keywords : coronal mass ejections * solar radio emissions * interplanetary particles Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.103, year: 2001

Influence of probe motion on laser probe temperature in circulating blood.

Science.gov (United States)

Hehrlein, C; Splinter, R; Littmann, L; Tuntelder, J R; Tatsis, G P; Svenson, R H

1991-01-01

The purpose of this study was to evaluate the effect of probe motion on laser probe temperature in various blood flow conditions. Laser probe temperatures were measured in an in vitro blood circulation model consisting of 3.2 nm-diameter plastic tubes. A 2.0 mm-diameter metal probe attached to a 300 microns optical quartz fiber was coupled to an argon laser. Continuous wave 4 watts and 8 watts of laser power were delivered to the fiber tip corresponding to a 6.7 +/- 0.5 and 13.2 +/- 0.7 watts power setting at the laser generator. The laser probe was either moved with constant velocity or kept stationary. A thermocouple inserted in the lateral portion of the probe was used to record probe temperatures. Probe temperature changes were found with the variation of laser power, probe velocity, blood flow, and duration of laser exposure. Probe motion significantly reduced probe temperatures. After 10 seconds of 4 watts laser power the probe temperature in stagnant blood decreased from 303 +/- 18 degrees C to 113 +/- 17 degrees C (63%) by moving the probe with a velocity of 5 cm/sec. Blood flow rates of 170 ml/min further decreased the probe temperature from 113 +/- 17 degrees C to 50 +/- 8 degrees C (56%). At 8 watts of laser power a probe temperature reduction from 591 +/- 25 degrees C to 534 +/- 36 degrees C (10%) due to 5 cm/sec probe velocity was noted. Probe temperatures were reduced to 130 +/- 30 degrees C (78%) under the combined influence of 5 cm/sec probe velocity and 170 ml/min blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Viruses transfer the antiviral second messenger cGAMP between cells.

Science.gov (United States)

Bridgeman, A; Maelfait, J; Davenne, T; Partridge, T; Peng, Y; Mayer, A; Dong, T; Kaever, V; Borrow, P; Rehwinkel, J

2015-09-11

Cyclic GMP-AMP synthase (cGAS) detects cytosolic DNA during virus infection and induces an antiviral state. cGAS signals by synthesis of a second messenger, cyclic GMP-AMP (cGAMP), which activates stimulator of interferon genes (STING). We show that cGAMP is incorporated into viral particles, including lentivirus and herpesvirus virions, when these are produced in cGAS-expressing cells. Virions transferred cGAMP to newly infected cells and triggered a STING-dependent antiviral program. These effects were independent of exosomes and viral nucleic acids. Our results reveal a way by which a signal for innate immunity is transferred between cells, potentially accelerating and broadening antiviral responses. Moreover, infection of dendritic cells with cGAMP-loaded lentiviruses enhanced their activation. Loading viral vectors with cGAMP therefore holds promise for vaccine development. Copyright © 2015, American Association for the Advancement of Science.

MESSENGER observations of transient bursts of energetic electrons in Mercury's magnetosphere.

Science.gov (United States)

Ho, George C; Krimigis, Stamatios M; Gold, Robert E; Baker, Daniel N; Slavin, James A; Anderson, Brian J; Korth, Haje; Starr, Richard D; Lawrence, David J; McNutt, Ralph L; Solomon, Sean C

2011-09-30

The MESSENGER spacecraft began detecting energetic electrons with energies greater than 30 kilo-electron volts (keV) shortly after its insertion into orbit about Mercury. In contrast, no energetic protons were observed. The energetic electrons arrive as bursts lasting from seconds to hours and are most intense close to the planet, distributed in latitude from the equator to the north pole, and present at most local times. Energies can exceed 200 keV but often exhibit cutoffs near 100 keV. Angular distributions of the electrons about the magnetic field suggest that they do not execute complete drift paths around the planet. This set of characteristics demonstrates that Mercury's weak magnetic field does not support Van Allen-type radiation belts, unlike all other planets in the solar system with internal magnetic fields.

Coupling coefficient between the Pc3 frequency and the value of the interplanetary magnetic field

International Nuclear Information System (INIS)

Gul'el'mi, A.V.

1988-01-01

Mean value and spread of coupling coefficient g between geomagnetic pulsation Ps3 frequency and interplanetary magnetic field (IMF) value are evaluated according to a set of all measurements described in literature and to additional measurements at Borok observatory (50 hour intervals in January, 1973). Attention is paid to a relatively small spread of g and to a weak g dependence on IMF orientation. The both facts are out of scope of the elementary Ps3 theory

Star Messenger: Galileo at the Millennium

Science.gov (United States)

White, R. E.

1999-05-01

Smith College has recently established the Louise B. and Edmund J. Kahn Liberal Arts Institute to foster interdisciplinary scholarship among the faculty. In the 1999-2000 academic year, the Kahn Institute is sponsoring a project entitled "Star Messenger: Galileo at the Millennium." The project will explore the impact of the astronomical discoveries of Galileo and his contemporaries on the Renaissance world-view and also use Galileo's experience as a lens for examining scientific and cultural developments at the symbolic juncture represented by the year 2000. Seven faculty fellows and 10-12 student fellows will participate in a year-long colloquium pursuing these themes, aided by the participation of some five Visiting Fellows. The inaugural public event will be a symposium on the historical Galileo, with presentation by three noted scholars, each of whom will return to campus for a second meeting with the Kahn colloquium. Additional events will include an exhibit of prints, artifacts, and rare books related to Galileo and his time, an early music concert featuring music composed by Galileo's father, and a series of other events sponsored by diverse departments and programs, all related to the broad themes of the Galileo project. The culminating events will be the premiere of a new music theater work, which will encapsulate the insights of the colloquium about human reactions to novel insights about the world, and a symposium presenting the research results of faculty and student fellows. The symposium will feature a capstone lecture by an visionary scholar projecting the implication of historical and contemporary trends into the future.

Forecasting intense geomagnetic activity using interplanetary magnetic field data

Science.gov (United States)

Saiz, E.; Cid, C.; Cerrato, Y.

2008-12-01

Southward interplanetary magnetic fields are considered traces of geoeffectiveness since they are a main agent of magnetic reconnection of solar wind and magnetosphere. The first part of this work revises the ability to forecast intense geomagnetic activity using different procedures available in the literature. The study shows that current methods do not succeed in making confident predictions. This fact led us to develop a new forecasting procedure, which provides trustworthy results in predicting large variations of Dst index over a sample of 10 years of observations and is based on the value Bz only. The proposed forecasting method appears as a worthy tool for space weather purposes because it is not affected by the lack of solar wind plasma data, which usually occurs during severe geomagnetic activity. Moreover, the results obtained guide us to provide a new interpretation of the physical mechanisms involved in the interaction between the solar wind and the magnetosphere using Faraday's law.

On interplanetary coronal mass ejection identification at 1 AU

International Nuclear Information System (INIS)

Mulligan, T.; Russell, C.T.; Gosling, J.T.

1999-01-01

Coronal mass ejections are believed to be produced in the corona from closed magnetic regions not previously participating in the solar wind expansion. At 1 AU their interplanetary counterparts (ICMEs) generally have a number of distinct plasma and field signatures that distinguish them from the ambient solar wind. These include heat flux dropouts, bi-directional streaming, enhanced alpha particle events, times of depressed proton temperatures, intervals of distorted or enhanced magnetic field, and times of large magnetic field rotations characteristic of magnetic clouds. The first three of these signatures are phenomena that occur at some point within the ICME, but do not necessarily persist throughout the entire ICME. The large scale magnetic field rotations, distortions and enhancements, and the proton temperature depressions tend to mark more accurately the beginning and end of the ICME proper. We examine herein the reliability with which each of these markers identifies ICMEs utilizing ISEE-3 data from 1978 - 1980. copyright 1999 American Institute of Physics

Interplanetary Trajectory Design for the Asteroid Robotic Redirect Mission Alternate Approach Trade Study

Science.gov (United States)

Merrill, Raymond Gabriel; Qu, Min; Vavrina, Matthew A.; Englander, Jacob A.; Jones, Christopher A.

2014-01-01

This paper presents mission performance analysis methods and results for the Asteroid Robotic Redirect Mission (ARRM) option to capture a free standing boulder on the surface of a 100 m or larger NEA. It details the optimization and design of heliocentric low-thrust trajectories to asteroid targets for the ARRM solar electric propulsion spacecraft. Extensive searches were conducted to determine asteroid targets with large pick-up mass potential and potential observation opportunities. Interplanetary trajectory approximations were developed in method based tools for Itokawa, Bennu, 1999 JU3, and 2008 EV5 and were validated by end-to-end integrated trajectories.

Mineralogy of Interplanetary Dust Particles from the Comet Giacobini-Zinner Dust Stream Collections

Science.gov (United States)

Nakamura-Messenger, K.; Messenger, S.; Westphal, A. J.; Palma, R. L.

2015-01-01

The Draconoid meteor shower, originating from comet 21P/Giacobini-Zinner, is a low-velocity Earth-crossing dust stream that had a peak anticipated flux on Oct. 8, 2012. In response to this prediction, NASA performed dedicated stratospheric dust collections to target interplanetary dust particles (IDPs) from this comet stream on Oct 15-17, 2012 [3]. Twelve dust particles from this targeted collection were allocated to our coordinated analysis team for studies of noble gas (Univ. Minnesota, Minnesota State Univ.), SXRF and Fe-XANES (SSL Berkeley) and mineralogy/isotopes (JSC). Here we report a mineralogical study of 3 IDPs from the Draconoid collection..

Solar and interplanetary particles at 2 to 4 MEV during solar cycles 21, solar cycle variations of event sizes, and compositions

International Nuclear Information System (INIS)

Armstrong, T.P.; Shields, J.C.; Briggs, P.R.; Eckes, S.

1985-01-01

In this paper 2 to 4 MeV/nucleon protons, alpha particles, and medium (CNO) nuclei in the near-Earth interplanetary medium during the years 1974 to 1981 are studied. This period contains both the solar activity minimum in 1976 and the very active onset phase of Solar Cycle 21. Characteristic compositional differences between the solar minimum and solar maximum ion populations have been investigated. Previous studies of interplanetary composition at these energies have concentrated on well-defined samples of the heliospheric medium. During flare particle events, the ambient plasma is dominated by ions accelerated in specific regions of the solar atmosphere; observation of the proton/alpha and alpha/medium ratios for flare events shows that there is marked compositional variability both during an event and from event to event suggesting the complicated nature of flare particle production and transport

Effect of the Global Topology of the Interplanetary Magnetic Field on the Properties of Impulsive Acceleration Processes in Distant Regions of the Earth's Magnetospheric Tail

International Nuclear Information System (INIS)

Grigorenko, E.E.; Zelenyi, L.M.; Fedorov, A.O.; Sauvaud, J.-A.

2005-01-01

The paper is devoted to a statistical study of high-speed ion beams (beamlets) observed by the Interball-1 and Interball-2 satellites in the boundary region of the plasma sheet of the geomagnetic tail and in the high-latitude auroral regions of the Earth's magnetosphere. Beamlets result from nonlinear acceleration processes occurring in the current sheet in the distant regions of the geomagnetic tail. They propagate toward the Earth along the magnetic field lines and are detected in the boundary region of the plasma sheet and near the high-latitude boundary of the plasma sheet in the auroral region in the form of short (with a duration of 1-2 min) bursts of high-energy (with energies of about several tens of keV) ions. The sizes of the latitudinal zones where the beamlets are localized in the tail and in the auroral region are determined using the epoch superposition method. The relationship between the frequency of beamlet generation in the boundary region of the plasma sheet and the prehistory of the direction of the interplanetary magnetic field (the magnitude of a clock angle) is investigated. It was established that this direction exerts a global effect on the beamlet generation frequency; moreover, it was found that the beamlet generation frequency in the midnight local time sector of the tail and at the flanks depends differently on the direction of the interplanetary magnetic field. In the midnight sector, the beamlets are observed at almost all directions of the interplanetary field, whereas the frequency of their generation at the flanks is maximal only when the interplanetary magnetic field has a large y component

Cyclic [G(2′,5′)pA(3′,5′)p] Is the Metazoan Second Messenger Produced by DNA-Activated Cyclic GMP-AMP Synthase

OpenAIRE

Gao, Pu; Ascano, Manuel; Wu, Yang; Barchet, Winfried; Gaffney, Barbara L.; Zillinger, Thomas; Serganov, Artem A.; Liu, Yizhou; Jones, Roger A.; Hartmann, Gunther; Tuschl, Thomas; Patel, Dinshaw J.

2013-01-01

Recent studies identified cyclic GMP-AMP (cGAMP) as a metazoan second messenger triggering an interferon response. cGAMP is generated from GTP and ATP by cytoplasmic dsDNA sensor cGAMP synthase (cGAS). We combined structural, chemical, biochemical, and cellular assays to demonstrate that this second messenger contains G(2′,5′)pA and A(3′,5′)pG phosphodiester linkages, designated c[G(2′,5′) pA(3′,5′)p]. We show that, upon dsDNA binding, cGAS is activated through conformational transitions, res...

Orbital Normalization of MESSENGER Gamma-Ray Spectrometer Data

Science.gov (United States)

Rhodes, E. A.; Peplowski, P. N.; Evans, L. G.; Hamara, D. K.; Boynton, W. V.; Solomon, S. C.

2011-12-01

The MESSENGER Gamma-Ray Spectrometer (GRS) measures energy spectra of gamma rays emanating from the surface of Mercury. Analysis of these spectra provides elemental abundances of surface material. The MESSENGER mission necessarily provides some data normalization challenges for GRS analysis. So as to keep the spacecraft cool while orbiting the dayside of the planet, the orbits are highly eccentric, with altitudes varying from 200-500 km to ~ 15,000 km. A small fraction of time is spent at the low altitudes where gamma-ray signals are largest, requiring a large number of orbits to yield sufficient counting statistics for elemental analysis. Also, the sunshade must always shield the spacecraft from the Sun, which causes the orientation of the GRS often to be far from nadir-pointing, so the detector efficiency and attenuation of gamma rays from the planet must be known for a wide range of off-nadir orientations. An efficiency/attenuation map for the expected ranges of orientations and energies was constructed in a ground calibration experiment for a limited range of orientations using a nuclear reactor and radioisotope sources, and those results were extended to other orientations by radiation transport computations using as input a computer-aided design model of the spacecraft and its composition. This normalization has allowed abundance determinations of elements K, Th, and U from radioisotopes of these elements in the Mercury regolith during the first quarter of the year-long mission. These results provide constraints on models of Mercury's chemical and thermal evolution. The normalization of gamma-ray spectra for surface elements not having radioisotopes is considerably more complex; these gamma rays come from neutron inelastic-scatter and capture reactions in the regolith, where the neutrons are generated by cosmic ray impact onto the planet. A radiation transport computation was performed to generate the expected count rates in the neutron-generated gamma

Differences in Brand Image of Online Chat Application of Blackberry Messenger, Whatsapp, and Line for Bina Nusantara University’s Student

Directory of Open Access Journals (Sweden)

Kuspuji C. B. Wicaksono

2016-05-01

Full Text Available This article was written to find out whether there were any differences on brand image for each online chat Application such as Blackberry Messenger, Whatsapp, and LINE based on six factors of the brand image which are: benefits, attributes, cultures, values, personality, and user. Data for the research were collected from questionnaires given to respondents who had used each mention online chat application. Then each respondent was asked to give scores based on the six factors of brand image for each online chat Application. Using the ANOVA method for testing the differences between brand images for each online chat application. The result reveales that there are differences in the brand image between BlackBerry Messenger, Whatsapp, and LINE for benefits, cultures, and values. There is no difference in attributes, and personality cannot be tested. The company that creates online chat application are expected to improve their brand image to distinguish one another differently.

Structures of interplanetary magnetic flux ropes and comparison with their solar sources

Energy Technology Data Exchange (ETDEWEB)

Hu, Qiang [Department of Space Science/CSPAR, University of Alabama in Huntsville, Huntsville, AL 35805 (United States); Qiu, Jiong [Department of Physics, Montana State University, Bozeman, MT 59717-3840 (United States); Dasgupta, B.; Khare, A.; Webb, G. M., E-mail: qh0001@uah.edu, E-mail: qiu@physics.montana.edu [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35805 (United States)

2014-09-20

Whether a magnetic flux rope is pre-existing or formed in situ in the Sun's atmosphere, there is little doubt that magnetic reconnection is essential to release the flux rope during its ejection. During this process, the question remains: how does magnetic reconnection change the flux-rope structure? In this work, we continue with the original study of Qiu et al. by using a larger sample of flare-coronal mass ejection (CME)-interplanetary CME (ICME) events to compare properties of ICME/magnetic cloud (MC) flux ropes measured at 1 AU and properties of associated solar progenitors including flares, filaments, and CMEs. In particular, the magnetic field-line twist distribution within interplanetary magnetic flux ropes is systematically derived and examined. Our analysis shows that, similar to what was found before, for most of these events, the amount of twisted flux per AU in MCs is comparable with the total reconnection flux on the Sun, and the sign of the MC helicity is consistent with the sign of the helicity of the solar source region judged from the geometry of post-flare loops. Remarkably, we find that about half of the 18 magnetic flux ropes, most of them associated with erupting filaments, have a nearly uniform and relatively low twist distribution from the axis to the edge, and the majority of the other flux ropes exhibit very high twist near the axis, up to ≳ 5 turns per AU, which decreases toward the edge. The flux ropes are therefore not linearly force-free. We also conduct detailed case studies showing the contrast of two events with distinct twist distribution in MCs as well as different flare and dimming characteristics in solar source regions, and discuss how reconnection geometry reflected in flare morphology may be related to the structure of the flux rope formed on the Sun.

Acceleration of H, He, and heavy ions observed in the magnetosheath, magnetotail, and near-by interplanetary space

International Nuclear Information System (INIS)

Fan, C.Y.; Gloeckler, G.; Hovestadt, D.

1975-01-01

Pulses of electrons and ions composed of H, He, and heavier elements were observed in the magnetosheath, magnetotail, and near-by interplanetary space. From the spatial positions where these particles were detected and the ion flow directions we conclude that they were accelerated at the bow shock near the sub-solar point and in the near-earth region of the neutral sheet of the magnetotail. (orig.) [de

On an effect of interplanetary magnetic field on a distribution electric fields in the polar ionosphere

International Nuclear Information System (INIS)

Uvarov, V.M.; Barashkov, P.D.

1985-01-01

The problem on the effect of the interplanetary magnetic field (IMF) on the distribution of electric fields in polar ionosphere is discussed. The problem on excitation of electric fields is reduced to the solution of the system of continuity equations for the current in three regions-northern polar cap, southern cap and the region outside the caps. It is shown that one succeeds in reproducing the observed types of distributions of electric fields

An analysis of interplanetary scintillation as a method of measuring the angular sizes of radio sources

International Nuclear Information System (INIS)

Hajivassiliou, C.A.; Duffett-Smith, P.J.

1990-01-01

Interplanetary scintillation has been widely used at metre wavelengths for estimating the angular sizes of radio sources in the range 0.1-2.0 arcsec. The estimates are based on observations of either the width of the temporal power spectrum or the shape of the scintillation index-elongation curve. We present a mathematical model of the latter procedure which reveals the biases introduced into an IPS survey as a result of the estimation process. (author)

Interplanetary outpost the human and technological challenges of exploring the outer planets

CERN Document Server

Seedhouse, Erik

2012-01-01

Water has been discovered on the Saturnian moon, Enceladus, and on Jupiter's moons, Europa, Ganymede, and Callisto. Where there is water, could there be life? Could this tantalizing possibility result in a manned mission to the outer planets? But how will such a mission be designed, what propulsion system will be used, and what hazards will the crewmembers face? Interplanetary Outpost describes step by step how the mission architecture will evolve, how crews will be selected and trained, and what the mission will entail from launch to landing. It addresses the effects that exteneded duration, radiation, communication, and isolation will have on the human body, and how not only performance but behavior might be affected.

Multiple spacecraft observations of interplanetary shocks: four spacecraft determination of shock normals

International Nuclear Information System (INIS)

Russell, C.T.; Mellott, M.M.; Smith, E.J.; King, J.H.

1983-01-01

ISEE 1,2,3 IMP8, and Prognoz 7 observations of interplanetary shocks in 1978 and 1979 provide five instances where a single shock is observed by four spacecraft. These observations are used to determine best-fit normals for these five shocks. In addition to providing well-documented shocks for furture techniques. When the angle between upstream and downstream magnetic field is greater than 20, magnetic coplanarity can be an accurate single spacecraft method. However, no technique based solely on the magnetic measurements at one or multiple sites was universally accurate. Thus, we recommend using overdetermined shock normal solutions whenever possible, utilizing plasma measurements, separation vectors, and time delays together with magnetic constraints

The major-element composition of Mercury's surface from MESSENGER X-ray spectrometry.

Science.gov (United States)

Nittler, Larry R; Starr, Richard D; Weider, Shoshana Z; McCoy, Timothy J; Boynton, William V; Ebel, Denton S; Ernst, Carolyn M; Evans, Larry G; Goldsten, John O; Hamara, David K; Lawrence, David J; McNutt, Ralph L; Schlemm, Charles E; Solomon, Sean C; Sprague, Ann L

2011-09-30

X-ray fluorescence spectra obtained by the MESSENGER spacecraft orbiting Mercury indicate that the planet's surface differs in composition from those of other terrestrial planets. Relatively high Mg/Si and low Al/Si and Ca/Si ratios rule out a lunarlike feldspar-rich crust. The sulfur abundance is at least 10 times higher than that of the silicate portion of Earth or the Moon, and this observation, together with a low surface Fe abundance, supports the view that Mercury formed from highly reduced precursor materials, perhaps akin to enstatite chondrite meteorites or anhydrous cometary dust particles. Low Fe and Ti abundances do not support the proposal that opaque oxides of these elements contribute substantially to Mercury's low and variable surface reflectance.

A Two-Sided Market Model of Optimal Price Structure for Instant Messenger

Directory of Open Access Journals (Sweden)

Jun Xu

2013-01-01

Full Text Available Instant messenger (IM is one of the most popular Internet applications all over the world. This paper examines the pricing problem of IM based on two-sided market model. IM serves as a two-sided platform, which gets both Internet users and advertisers on board. This paper concludes that IM operator adopts a heavily skewed price structure that favors IM users both under monopolistic case and under horizontal differentiated duopolistic case. When advertising revenue is large enough relatively to marginal cost for serving IM users, IM users can enjoy free service provided by IM operators. The competitive equilibrium of duopolistic case is not necessarily symmetric when advertisers choose singlehoming. Even in the symmetric equilibrium platform would rather deter all advertisers.

Internet messenger based smart virtual class learning using ubiquitous computing

Science.gov (United States)

Umam, K.; Mardi, S. N. S.; Hariadi, M.

2017-06-01

Internet messenger (IM) has become an important educational technology component in college education, IM makes it possible for students to engage in learning and collaborating at smart virtual class learning (SVCL) using ubiquitous computing. However, the model of IM-based smart virtual class learning using ubiquitous computing and empirical evidence that would favor a broad application to improve engagement and behavior are still limited. In addition, the expectation that IM based SVCL using ubiquitous computing could improve engagement and behavior on smart class cannot be confirmed because the majority of the reviewed studies followed instructions paradigms. This article aims to present the model of IM-based SVCL using ubiquitous computing and showing learners’ experiences in improved engagement and behavior for learner-learner and learner-lecturer interactions. The method applied in this paper includes design process and quantitative analysis techniques, with the purpose of identifying scenarios of ubiquitous computing and realize the impressions of learners and lecturers about engagement and behavior aspect and its contribution to learning

Topography of the Northern Hemisphere of Mercury from MESSENGER Laser Altimetry

Science.gov (United States)

Zuber,Maria T.; Smith, David E.; Phillips, Roger J.; Solomon, Sean C.; Neumann, Gregory A.; Hauck, Steven A., Jr.; Peale, Stanton J.; Barnouin, Oliver S.; Head, James W.; Johnson, Catherine L.;

Long-term Longitudinal Recurrences of the Open Magnetic Flux Density in the Heliosphere

Energy Technology Data Exchange (ETDEWEB)

Dósa, M.; Erdős, G., E-mail: dosa.melinda@wigner.mta.hu [Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1121 Budapest, Konkoly-Thege Miklós st 29-33 (Hungary)

2017-04-01

Open magnetic flux in the heliosphere is determined from the radial component of the magnetic field vector measured onboard interplanetary space probes. Previous Ulysses research has shown remarkable independence of the flux density from heliographic latitude, explained by super-radial expansion of plasma. Here we are investigating whether any longitudinal variation exists in the 50 year long OMNI magnetic data set. The heliographic longitude of origin of the plasma package was determined by applying a correction according to the solar wind travel time. Significant recurrent enhancements of the magnetic flux density were observed throughout solar cycle 23, lasting for several years. Similar, long-lasting recurring features were observed in the solar wind velocity, temperature and the deviation angle of the solar wind velocity vector from the radial direction. Each of the recurrent features has a recurrence period slightly differing from the Carrington rotation rate, although they show a common trend in time. Examining the coronal temperature data of ACE leads to the possible explanation that these long-term structures are caused by slow–fast solar wind interaction regions. A comparison with MESSENGER data measured at 0.5 au shows that these longitudinal magnetic modulations do not exist closer to the Sun, but are the result of propagation.

Automated trajectory planning for multiple-flyby interplanetary missions

Science.gov (United States)

Englander, Jacob

Many space mission planning problems may be formulated as hybrid optimal control problems (HOCP), i.e. problems that include both real-valued variables and categorical variables. In interplanetary trajectory design problems the categorical variables will typically specify the sequence of planets at which to perform flybys, and the real-valued variables will represent the launch date, ight times between planets, magnitudes and directions of thrust, flyby altitudes, etc. The contribution of this work is a framework for the autonomous optimization of multiple-flyby interplanetary trajectories. The trajectory design problem is converted into a HOCP with two nested loops: an "outer-loop" that finds the sequence of flybys and an "inner-loop" that optimizes the trajectory for each candidate yby sequence. The problem of choosing a sequence of flybys is posed as an integer programming problem and solved using a genetic algorithm (GA). This is an especially difficult problem to solve because GAs normally operate on a fixed-length set of decision variables. Since in interplanetary trajectory design the number of flyby maneuvers is not known a priori, it was necessary to devise a method of parameterizing the problem such that the GA can evolve a variable-length sequence of flybys. A novel "null gene" transcription was developed to meet this need. Then, for each candidate sequence of flybys, a trajectory must be found that visits each of the flyby targets and arrives at the final destination while optimizing some cost metric, such as minimizing ▵v or maximizing the final mass of the spacecraft. Three different classes of trajectory are described in this work, each of which requireda different physical model and optimization method. The choice of a trajectory model and optimization method is especially challenging because of the nature of the hybrid optimal control problem. Because the trajectory optimization problem is generated in real time by the outer-loop, the inner

Four-probe measurements with a three-probe scanning tunneling microscope

International Nuclear Information System (INIS)

Salomons, Mark; Martins, Bruno V. C.; Zikovsky, Janik; Wolkow, Robert A.

2014-01-01

We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe

Four-probe measurements with a three-probe scanning tunneling microscope

Energy Technology Data Exchange (ETDEWEB)

Salomons, Mark [National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta T6G 2M9 (Canada); Martins, Bruno V. C.; Zikovsky, Janik; Wolkow, Robert A., E-mail: rwolkow@ualberta.ca [National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta T6G 2M9 (Canada); Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)

2014-04-15

We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

Four-probe measurements with a three-probe scanning tunneling microscope.

Science.gov (United States)

Salomons, Mark; Martins, Bruno V C; Zikovsky, Janik; Wolkow, Robert A

2014-04-01

We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

Intense energetic electron flux enhancements in Mercury's magnetosphere: An integrated view with high-resolution observations from MESSENGER.

Science.gov (United States)

Baker, Daniel N; Dewey, Ryan M; Lawrence, David J; Goldsten, John O; Peplowski, Patrick N; Korth, Haje; Slavin, James A; Krimigis, Stamatios M; Anderson, Brian J; Ho, George C; McNutt, Ralph L; Raines, Jim M; Schriver, David; Solomon, Sean C

2016-03-01

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission to Mercury has provided a wealth of new data about energetic particle phenomena. With observations from MESSENGER's Energetic Particle Spectrometer, as well as data arising from energetic electrons recorded by the X-Ray Spectrometer and Gamma-Ray and Neutron Spectrometer (GRNS) instruments, recent work greatly extends our record of the acceleration, transport, and loss of energetic electrons at Mercury. The combined data sets include measurements from a few keV up to several hundred keV in electron kinetic energy and have permitted relatively good spatial and temporal resolution for many events. We focus here on the detailed nature of energetic electron bursts measured by the GRNS system, and we place these events in the context of solar wind and magnetospheric forcing at Mercury. Our examination of data at high temporal resolution (10 ms) during the period March 2013 through October 2014 supports strongly the view that energetic electrons are accelerated in the near-tail region of Mercury's magnetosphere and are subsequently "injected" onto closed magnetic field lines on the planetary nightside. The electrons populate the plasma sheet and drift rapidly eastward toward the dawn and prenoon sectors, at times executing multiple complete drifts around the planet to form "quasi-trapped" populations.

The Effect of WhatsApp Messenger As Mobile Learning Integrated with Group Investigation Method of Learning Achievement

Directory of Open Access Journals (Sweden)

Hendrik Pratama

2017-12-01

Full Text Available The purpose of this research was determined the effect of application WhatsApp Messenger in the Group Investigation (GI method on learning achievement. The methods used experimental research with control group pretest-postest design. The sampling procedure used the purposive sampling technique that consists of 17 students as a control group and 17 students as an experimental group. The sample in this research is students in Electrical Engineering Education Study Program. The experimental group used the GI method that integrated with WhatsApp Messenger. The control group used lecture method without social media integration. The collecting data used observation, documentation, interview, questionnaire, and test. The researcher used a t-test for compared the control group and the experimental group’s learning outcomes at an alpha level of 0,05. The results showed differences between the experiment group and the control group. The study result of the experimental higher than the control groups. This learning was designed with start, grouping, planning, presenting, organizing, investigating, evaluating, ending’s stage. Integration of WhatsApp with group investigation method could cause the positive communication between student and lecturer. Discussion in this learning was well done, the student’s knowledge could appear in a group and the information could spread evenly and quickly.

Compact, Passively Q-Switched Nd:YAG Laser for the MESSENGER Mission to the Planet Mercury

Science.gov (United States)

Krebs, Danny J.; Novo-Gradac, Anne-Marie; Li, Steven X.; Lindauer, Steven J.; Afzal, Robert S.; Yu, Antony

2004-01-01

A compact, passively Q-switched Nd:YAG laser has been developed for the Mercury Laser Altimeter (MLA) instrument which is an instrument on the MESSENGER mission to the planet Mercury. The laser achieves 5.4 percent efficiency with a near diffraction limited beam. It has passed all space flight environmental tests at system, instrument, and satellite integration. The laser design draws on a heritage of previous laser altimetry missions, specifically ISESAT and Mars Global Surveyor; but incorporates thermal management features unique to the requirements of an orbit of the planet Mercury.

The interplanetary magnetic field observed by Juno enroute to Jupiter

Science.gov (United States)

Gruesbeck, Jacob R.; Gershman, Daniel J.; Espley, Jared R.; Connerney, John E. P.

2017-06-01

The Juno spacecraft was launched on 5 August 2011 and spent nearly 5 years traveling through the inner heliosphere on its way to Jupiter. The Magnetic Field Investigation was powered on shortly after launch and obtained vector measurements of the interplanetary magnetic field (IMF) at sample rates from 1 to 64 samples/second. The evolution of the magnetic field with radial distance from the Sun is compared to similar observations obtained by Voyager 1 and 2 and the Ulysses spacecraft, allowing a comparison of the radial evolution between prior solar cycles and the current depressed one. During the current solar cycle, the strength of the IMF has decreased throughout the inner heliosphere. A comparison of the variance of the normal component of the magnetic field shows that near Earth the variability of the IMF is similar during all three solar cycles but may be less at greater radial distances.

Geoeffectiveness of interplanetary shocks controlled by impact angles: A review

Science.gov (United States)

Oliveira, D. M.; Samsonov, A. A.

2018-01-01

The high variability of the Sun's magnetic field is responsible for the generation of perturbations that propagate throughout the heliosphere. Such disturbances often drive interplanetary shocks in front of their leading regions. Strong shocks transfer momentum and energy into the solar wind ahead of them which in turn enhance the solar wind interaction with magnetic fields in its way. Shocks then eventually strike the Earth's magnetosphere and trigger a myriad of geomagnetic effects observed not only by spacecraft in space, but also by magnetometers on the ground. Recently, it has been revealed that shocks can show different geoeffectiveness depending closely on the angle of impact. Generally, frontal shocks are more geoeffective than inclined shocks, even if the former are comparatively weaker than the latter. This review is focused on results obtained from modeling and experimental efforts in the last 15 years. Some theoretical and observational background are also provided.

The Interplanetary Magnetic Field Observed by Juno Enroute to Jupiter

Science.gov (United States)

Gruesbeck, Jacob R.; Gershman, Daniel J.; Espley, Jared R.; Connerney, John E. P.

2017-01-01

The Juno spacecraft was launched on 5 August 2011 and spent nearly 5 years traveling through the inner heliosphere on its way to Jupiter. The Magnetic Field Investigation was powered on shortly after launch and obtained vector measurements of the interplanetary magnetic field (IMF) at sample rates from 1 to 64 samples/second. The evolution of the magnetic field with radial distance from the Sun is compared to similar observations obtained by Voyager 1 and 2 and the Ulysses spacecraft, allowing a comparison of the radial evolution between prior solar cycles and the current depressed one. During the current solar cycle, the strength of the IMF has decreased throughout the inner heliosphere. A comparison of the variance of the normal component of the magnetic field shows that near Earth the variability of the IMF is similar during all three solar cycles but may be less at greater radial distances.

Dynamical modeling approach to risk assessment for radiogenic leukemia among astronauts engaged in interplanetary space missions.

Science.gov (United States)

Smirnova, Olga A; Cucinotta, Francis A

2018-02-01

A recently developed biologically motivated dynamical model of the assessment of the excess relative risk (ERR) for radiogenic leukemia among acutely/continuously irradiated humans (Smirnova, 2015, 2017) is applied to estimate the ERR for radiogenic leukemia among astronauts engaged in long-term interplanetary space missions. Numerous scenarios of space radiation exposure during space missions are used in the modeling studies. The dependence of the ERR for leukemia among astronauts on several mission parameters including the dose equivalent rates of galactic cosmic rays (GCR) and large solar particle events (SPEs), the number of large SPEs, the time interval between SPEs, mission duration, the degree of astronaut's additional shielding during SPEs, the degree of their additional 12-hour's daily shielding, as well as the total mission dose equivalent, is examined. The results of the estimation of ERR for radiogenic leukemia among astronauts, which are obtained in the framework of the developed dynamical model for various scenarios of space radiation exposure, are compared with the corresponding results, computed by the commonly used linear model. It is revealed that the developed dynamical model along with the linear model can be applied to estimate ERR for radiogenic leukemia among astronauts engaged in long-term interplanetary space missions in the range of applicability of the latter. In turn, the developed dynamical model is capable of predicting the ERR for leukemia among astronauts for the irradiation regimes beyond the applicability range of the linear model in emergency cases. As a supplement to the estimations of cancer incidence and death (REIC and REID) (Cucinotta et al., 2013, 2017), the developed dynamical model for the assessment of the ERR for leukemia can be employed on the pre-mission design phase for, e.g., the optimization of the regimes of astronaut's additional shielding in the course of interplanetary space missions. The developed model can

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....

The Effects of a Synchronous Communication Tool (Yahoo Messenger) on Online Learners' Sense of Community and Their Multimedia Authoring Skills

Science.gov (United States)

Wang, Shiang-Kwei

2008-01-01

Literature suggests that developing a community of learners is the key to a successful online-learning experience. In this study, the instructor of a multimedia authoring course adopted a synchronous communication tool (Yahoo Messenger) to interact with learners orally on a weekly basis and, thereby, to establish a sense among the learners that…

The O+ contribution and role on the ring current pressure development for CMEs and CIRs using Van Allen Probes observations

Science.gov (United States)

Mouikis, C.; Bingham, S.; Kistler, L. M.; Farrugia, C. J.; Spence, H. E.; Gkioulidou, M.

2016-12-01

The ring current responds differently to the different solar and interplanetary storm drivers such as coronal mass injections, (CME's), co-rotating interaction regions (CIR's), high-speed streamers and other structures. The resulting changes in the ring current particle pressure change the global magnetic field, which affects the transport of the radiation belts. In order to determine the field changes during a storm, it is necessary to understand the transport, sources and losses of the particles that contribute to the ring current. The source population of the storm time ring current is the night side plasma sheet. We use Van Allen Probes observations to determine the ring current pressure contribution of the convecting plasma sheet H+ and O+ particles in the storm time development of the ring current. We compare storms that are related to different interplanetary drivers, CMEs and CIRs, as observed at different local times. We find that during the storm main phase most of the ring current pressure in the pre-midnight inner magnetosphere is contributed by particles on open drift paths that cause the development of a strong partial ring current that causes most of the main phase Dst drop. These particles can reach as deep as L 2 and their pressure compares to the local magnetic field pressure as deep as L 3. During the recovery phase, if these particles are not lost at the magnetopause, will become trapped and will contribute to the symmetric ring current. However, the largest difference between the CME and CIR ring current responses during the storm main and early recovery phases is caused by how the 15 - 60 keV O+ responds to these drivers.

Non-Gaussianity and cross-scale coupling in interplanetary magnetic field turbulence during a rope-rope magnetic reconnection event

Science.gov (United States)

Miranda, Rodrigo A.; Schelin, Adriane B.; Chian, Abraham C.-L.; Ferreira, José L.

2018-03-01

In a recent paper (Chian et al., 2016) it was shown that magnetic reconnection at the interface region between two magnetic flux ropes is responsible for the genesis of interplanetary intermittent turbulence. The normalized third-order moment (skewness) and the normalized fourth-order moment (kurtosis) display a quadratic relation with a parabolic shape that is commonly observed in observational data from turbulence in fluids and plasmas, and is linked to non-Gaussian fluctuations due to coherent structures. In this paper we perform a detailed study of the relation between the skewness and the kurtosis of the modulus of the magnetic field |B| during a triple interplanetary magnetic flux rope event. In addition, we investigate the skewness-kurtosis relation of two-point differences of |B| for the same event. The parabolic relation displays scale dependence and is found to be enhanced during magnetic reconnection, rendering support for the generation of non-Gaussian coherent structures via rope-rope magnetic reconnection. Our results also indicate that a direct coupling between the scales of magnetic flux ropes and the scales within the inertial subrange occurs in the solar wind.

Traversing probe system

Science.gov (United States)

Mashburn, Douglas N.; Stevens, Richard H.; Woodall, Harold C.

1977-01-01

This invention comprises a rotatable annular probe-positioner which carries at least one radially disposed sensing probe, such as a Pitot tube having a right-angled tip. The positioner can be coaxially and rotatably mounted within a compressor casing or the like and then actuated to orient the sensing probe as required to make measurements at selected stations in the annulus between the positioner and compressor casing. The positioner can be actuated to (a) selectively move the probe along its own axis, (b) adjust the yaw angle of the right-angled probe tip, and (c) revolve the probe about the axis common to the positioner and casing. A cam plate engages a cam-follower portion of the probe and normally rotates with the positioner. The positioner includes a first-motor-driven ring gear which effects slidable movement of the probe by rotating the positioner at a time when an external pneumatic cylinder is actuated to engage the cam plate and hold it stationary. When the pneumatic cylinder is not actuated, this ring gear can be driven to revolve the positioner and thus the probe to a desired circumferential location about the above-mentioned common axis. A second motor-driven ring gear included in the positioner can be driven to rotate the probe about its axis, thus adjusting the yaw angle of the probe tip. The positioner can be used in highly corrosive atmosphere, such as gaseous uranium hexafluoride.

Traversing probe system

International Nuclear Information System (INIS)

Mashburn, D.N.; Stevens, R.H.; Woodall, H.C.

1977-01-01

This invention comprises a rotatable annular probe-positioner which carries at least one radially disposed sensing probe, such as a Pitot tube having a right-angled tip. The positioner can be coaxially and rotatably mounted within a compressor casing or the like and then actuated to orient the sensing probe as required to make measurements at selected stations in the annulus between the positioner and compressor casing. The positioner can be actuated to (a) selectively move the probe along its own axis, (b) adjust the yaw angle of the right-angled probe tip, and (c) revolve the probe about the axis common to the positioner and casing. A cam plate engages a cam-follower portion of the probe and normally rotates with the positioner. The positioner includes a first-motor-driven ring gear which effects slidable movement of the probe by rotating the positioner at a time when an external pneumatic cylinder is actuated to engage the cam plate and hold it stationary. When the pneumatic cylinder is not actuated, this ring gear can be driven to revolve the positioner and thus the probe to a desired circumferential location about the above-mentioned common axis. A second motor-driven ring gear included in the positioner can be driven to rotate the probe about its axis, thus adjusting the yaw angle of the probe tip. The positioner can be used in highly corrosive atmosphere, such as gaseous uranium hexafluoride. 10 claims, 6 figures

Influence of probe geometry on the response of an electrostatic probe

DEFF Research Database (Denmark)

Johansson, Torben; Crichton, George C; McAllister, Iain Wilson

1999-01-01

The response of an electrostatic probe is examined with reference to the probe geometry. The study involves the evaluation of the probe lambda function, from which response-related characteristic parameters can be derived. These parameters enable the probe detection sensitivity Se and spatial...

Effective Acceleration Model for the Arrival Time of Interplanetary Shocks driven by Coronal Mass Ejections

Science.gov (United States)

Paouris, Evangelos; Mavromichalaki, Helen

2017-12-01

In a previous work (Paouris and Mavromichalaki in Solar Phys. 292, 30, 2017), we presented a total of 266 interplanetary coronal mass ejections (ICMEs) with as much information as possible. We developed a new empirical model for estimating the acceleration of these events in the interplanetary medium from this analysis. In this work, we present a new approach on the effective acceleration model (EAM) for predicting the arrival time of the shock that preceds a CME, using data of a total of 214 ICMEs. For the first time, the projection effects of the linear speed of CMEs are taken into account in this empirical model, which significantly improves the prediction of the arrival time of the shock. In particular, the mean value of the time difference between the observed time of the shock and the predicted time was equal to +3.03 hours with a mean absolute error (MAE) of 18.58 hours and a root mean squared error (RMSE) of 22.47 hours. After the improvement of this model, the mean value of the time difference is decreased to -0.28 hours with an MAE of 17.65 hours and an RMSE of 21.55 hours. This improved version was applied to a set of three recent Earth-directed CMEs reported in May, June, and July of 2017, and we compare our results with the values predicted by other related models.