WorldWideScience

Sample records for current asteroid survey

  1. Selecting asteroids for a targeted spectroscopic survey

    CERN Document Server

    Oszkiewicz, D A; Tomov, T; Birlan, M; Geier, S; Penttilä, A; Polińska, M

    2014-01-01

    Asteroid spectroscopy reflects surface mineralogy. There are few thousand asteroids whose surfaces have been observed spectrally. Determining the surface properties of those objects is important for many practical and scientific applications, such as for example developing impact deflection strategies or studying history and evolution of the Solar System and planet formation. The aim of this study is to develop a pre-selection method that can be utilized in searching for asteroids of any taxonomic complex. The method could then be utilized im multiple applications such as searching for the missing V-types or looking for primitive asteroids. We used the Bayes Naive Classifier combined with observations obtained in the course of the Sloan Digital Sky Survey and the Wide-field Infrared Survey Explorer surveys as well as a database of asteroid phase curves for asteroids with known taxonomic type. Using the new classification method we have selected a number of possible V-type candidates. Some of the candidates we...

  2. Hungaria asteroid region telescopic spectral survey (HARTSS) I: Stony asteroids abundant in the Hungaria background population

    Science.gov (United States)

    Lucas, Michael P.; Emery, Joshua P.; Pinilla-Alonso, Noemi; Lindsay, Sean S.; Lorenzi, Vania

    2017-07-01

    The Hungaria asteroids remain as survivors of late giant planet migration that destabilized a now extinct inner portion of the primordial asteroid belt and left in its wake the current resonance structure of the Main Belt. In this scenario, the Hungaria region represents a ;purgatory; for the closest, preserved samples of the asteroidal material from which the terrestrial planets accreted. Deciphering the surface composition of these unique samples may provide constraints on the nature of the primordial building blocks of the terrestrial planets. We have undertaken an observational campaign entitled the Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) to record near-infrared (NIR) reflectance spectra in order to characterize their taxonomy, surface mineralogy, and potential meteorite analogs. The overall objective of HARTSS is to evaluate the compositional diversity of asteroids located throughout the Hungaria region. This region harbors a collisional family of Xe-type asteroids, which are situated among a background (i.e., non-family) of predominantly S-complex asteroids. In order to assess the compositional diversity of the Hungaria region, we have targeted background objects during Phase I of HARTSS. Collisional family members likely reflect the composition of one original homogeneous parent body, so we have largely avoided them in this phase. We have employed NIR instruments at two ground-based telescope facilities: the NASA Infrared Telescope Facility (IRTF), and the Telescopio Nazionale Galileo (TNG). Our data set includes the NIR spectra of 42 Hungaria asteroids (36 background; 6 family). We find that stony S-complex asteroids dominate the Hungaria background population (29/36 objects; ∼80%). C-complex asteroids are uncommon (2/42; ∼5%) within the Hungaria region. Background S-complex objects exhibit considerable spectral diversity as band parameter measurements of diagnostic absorption features near 1- and 2-μm indicate that several

  3. PRIMitive Asteroids Spectroscopic Survey - PRIMASS: First Results

    Science.gov (United States)

    de Leon, Julia; Pinilla-Alonso, Noemi; Campins, Humberto; Lorenzi, Vania; Licandro, Javier; Morate, David; Tanga, Paolo; Cellino, Alberto; Delbo, Marco

    2015-11-01

    NASA OSIRIS-REx and JAXA Hayabusa 2 sample-return missions have targeted two near-Earth asteroids: (101955) Bennu and (162173) 1999 JU3, respectively. These are primitive asteroids that are believed to originate in the inner belt, where five distinct sources have been identified: four primitive collisional families (Polana, Erigone, Sulamitis, and Clarissa), and a population of low-albedo and low-inclination background asteroids. Identifying and characterizing the populations from which these two NEAs might originate will enchance the science return of the two missions.With this main objective in mind, we initiated in 2010 a spectroscopic survey in the visible and the near-infrared to characterize the primitive collisional families in the inner belt and the low-albedo background population. This is the PRIMitive Asteroids Spectroscopic Survey - PRIMASS. So far we have obtained more than 200 spectra using telescopes located at different observatories. PRIMASS uses a variety of ground based facilities. Most of the spectra have been obtained using the 10.4m Gran Telescopio Canarias (GTC), and the 3.6m Telescopio Nazionale Galileo (TNG), both located at the El Roque de los Muchachos Observatory (La Palma, Spain), and the 3.0m NASA Infrared Telescope Facility on Mauna Kea (Hawai, USA).We present the first results from our on-going survey (de Leon et al. 2015; Pinilla-Alonso et al. 2015; Morate et al. 2015), focused on the Polana and the Erigone primitive families, with visible and near-infrared spectra of more than 200 objects, most of them with no previous spectroscopic data. Our survey is already the largest database of primitive asteroids spectra, and we keep obtaining data on the Sulamitis and the Clarissa families, as well as on the background low-albedo population.

  4. Spectroscopic survey of M--type asteroids

    CERN Document Server

    Fornasier, S; Dotto, E; Migliorini, A; Ockert-Bell, M; Barucci, M A

    2010-01-01

    M-type asteroids, as defined in the Tholen taxonomy (Tholen, 1984), are medium albedo bodies supposed to have a metallic composition and to be the progenitors both of differentiated iron-nickel meteorites and enstatite chondrites. We carried out a spectroscopic survey in the visible and near infrared wavelength range (0.4-2.5 micron) of 30 asteroids chosen from the population of asteroids initially classified as Tholen M -types, aiming to investigate their surface composition. The data were obtained during several observing runs during the years 2004-2007 at the TNG, NTT, and IRTF telescopes. We computed the spectral slopes in several wavelength ranges for each observed asteroid, and we searched for diagnostic spectral features. We confirm a large variety of spectral behaviors for these objects as their spectra are extended into the near-infrared, including the identification of weak absorption bands, mainly of the 0.9 micron band tentatively attributed to orthopyroxene, and of the 0.43 micron band that may b...

  5. ASTEROIDS

    Directory of Open Access Journals (Sweden)

    Željko Andreić

    2016-02-01

    Full Text Available Asteroids are the largest minor bodies in the Solar System. Nowadays they are in the research focus due to several facts about them: first, a subclass of asteroids can collide with Earth, and consequences of such a collision are dramatic. Second, they are now seen as source of materials that are becoming scarce on Earth, and they will be needed in future space constructions anyway. Third, they are holding clues about the origin and evolution of the Solar System. In this article, a short overview of current knowledge about asteroids is presented. Last, but not least, as several Croatian scientists were recently honored by naming an asteroid after them, a short overview of the naming process is given.

  6. Asteroid hyalosis--current state of knowledge.

    Science.gov (United States)

    Jabłońska, Anna; Ciszewska, Joanna; Kęcik, Dariusz

    2014-01-01

    The search query into the Cochrane Library, Medline, Web of Science, Embase, Scopus and ScienceDirect enabled selection of research papers addressing the issue of asteroid hyalosis published in English between 1963 and January 2014. Asteroid hyalosis is a degenerative condition of the vitreous in which small, creamy or white, spherical particles (asteroid bodies) are randomly diffused within the vitreous. They consist mainly of calcium and phosphorus and have a structure of hydroxy lapatite. In 80.2-92.0% of cases the condition affects one eye only and it occurs in 0.36-1.96% of population, mostly in patients over 50 years of age and in males. Hypercholesterolemia and hypertension are systemic risk factors, but asteroid hyalosis is postulated to occur more often in retinitis pigmentosa and Leber amaurosis caused by mutations in lecithin retinol acyltransferase gene. Asteroid hyalosis also causes calcification of some intraocular lenses--mostly silicone ones. Vitreous of patients with asteroid hyalosis shows reduced gel liquefaction and anomalous vitreoretinal adhesion.

  7. Spitzer Survey of the Karin Cluster Asteroids

    NARCIS (Netherlands)

    Harris, Alan W.; Mueller, M.; Lisse, C.; Cheng, A.; Osip, D.

    2007-01-01

    The Karin cluster is one of the youngest known families of main-belt asteroids, dating back to a collisional event only 5.8 Myr ago. Using the Spitzer Space Telescope we have sampled the thermal continua of 17 Karin cluster asteroids, down to the smallest members discovered so far, in order to deriv

  8. Spitzer Survey of the Karin Cluster Asteroids

    NARCIS (Netherlands)

    Harris, Alan W.; Mueller, M.; Lisse, C.; Cheng, A.; Osip, D.

    2007-01-01

    The Karin cluster is one of the youngest known families of main-belt asteroids, dating back to a collisional event only 5.8 Myr ago. Using the Spitzer Space Telescope we have sampled the thermal continua of 17 Karin cluster asteroids, down to the smallest members discovered so far, in order to

  9. Mining the CFHT Legacy Survey for known Near Earth Asteroids

    CERN Document Server

    Vaduvescu, O; Birlan, M; Toma, R; Badea, M; Dumitru, D; Opriseanu, C; Vidican, D; 10.1002/asna.201011550

    2011-01-01

    The Canada-France-Hawaii Legacy Survey (CFHTLS) comprising about 25 000 MegaCam images was data mined to search for serendipitous encounters of known Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 143 asteroids (109 NEAs and 34 PHAs) were found on 508 candidate images which were field corrected and measured carefully, and their astrometry was reported to Minor Planet Centre. Both recoveries and precoveries (apparitions before discovery) were reported, including data for 27 precovered asteroids (20 NEAs and 7 PHAs) and 116 recovered asteroids (89 NEAs and 27 PHAs). Our data prolonged arcs for 41 orbits at first or last opposition, refined 35 orbits by fitting data taken at one new opposition, recovered 6 NEAs at their second opposition and allowed us to ameliorate most orbits and their Minimal Orbital Intersection Distance (MOID), an important parameter to monitor for potential Earth impact hazard in the future.

  10. Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS): Stony Asteroids Abundant in the Background and Family Populations

    Science.gov (United States)

    Lucas, Michael P.; Emery, Joshua P.; Pinilla-Alonso, Noemi; Lindsay, Sean S.; Lorenzi, Vania

    2016-10-01

    The Hungaria region represents a "purgatory" for the closest, preserved samples of the material from which the terrestrial planets accreted. The Hungaria region harbors a collisional family of Xe-type asteroids, which are situated among a background of predominantly S-complex asteroids. Deciphering their surface composition may provide constraints on the nature of the primordial building blocks of the terrestrial planets. We hypothesize that planetesimals in the inner part of the primordial asteroid belt experienced partial- to full-melting and differentiation, the Hungaria region should retain any petrologically-evolved material that formed there.We have undertaken an observational campaign entitled the Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) to record near-infrared (NIR) spectra to characterize taxonomy, surface mineralogy, and potential meteorite analogs. We used NIR instruments at two ground-based facilities (NASA IRTF; TNG). Our data set includes spectra of 82 Hungaria asteroids (61 background; 21 family), 65 were observed during HARTSS. We compare S-complex background asteroids to calibrations developed via laboratory analyses of ordinary chondrites, and to our analyses (EPMA, XRD, VIS+NIR spectra) of 11 primitive achondrite (acapulcoite-lodranite clan) meteorites.We find that stony S-complex asteroids dominate the Hungaria background population (~80%). Background objects exhibit considerable spectral diversity, when quantified by spectral band parameter measurements, translates to a variety of surface compositions. Two main meteorite groups are represented within the Hungaria background: unmelted, nebular L chondrites (and/or L chondrites), and partially-melted primitive achondrites. H-chondrite mineralogies appear to be absent from the Hungaria background. Xe-type Hungaria family members exhibit spectral homogeneity, consistent with the hypothesis that the family was derived from the disruption of a parent body analogous to an enstatite

  11. Spectroscopic Survey of X-type Asteroids

    CERN Document Server

    Fornasier, Sonia; Dotto, Elisabetta

    2011-01-01

    We present reflected light spectral observations from 0.4 to 2.5 micron of 24 asteroids chosen from the population of asteroids initially classified as Tholen X-type objects (Tholen, 1984). The X complex in the Tholen taxonomy comprises the E, M and P classes which have very different inferred mineralogies but which are spectrally similar to each other, with featureless spectra in visible wavelengths. The data were obtained during several observing runs in the 2004-2007 years at the NTT, TNG and IRTF telescopes. We find a large variety of near-infrared spectral behaviors within the X class, and we identify weak absorption bands in spectra of 11 asteroids. Our spectra, together with albedos published by Tedesco et al. (2002), can be used to suggest new Tholen classifications for these objects. In order to constrain the possible composition of these asteroids, we perform a least-squares search through the RELAB spectral database. Many of the best fits are consistent with meteorite analogue materials suggested i...

  12. Automatic detection of asteroids and meteoroids. A Wide Field Survey

    Science.gov (United States)

    Vereš, P.; Tóth, J.; Jedicke, R.; Tonry, J.; Denneau, L.; Wainscoat, R.; Kornoš, L.; Šilha, J.

    2014-07-01

    We propose a low-cost robotic optical survey aimed at 1-300 m Near Earth Objects (NEO) based on four state-of-the-art telescopes having extremely wide field of view. The small Near-Earth Asteroids (NEA) represent a potential risk but also easily accessible space resources for future robotic or human space in-situ exploration, or commercial activities. The survey system will be optimized for the detection of fast moving-trailed-asteroids, space debris and will provide real-time alert notifications. The expected cost of the system including 1-year development and 2-year operation is 1,000,000 EUR. The successful demonstration of the system will promote cost-effectiveicient ADAM-WFS (Automatic Detection of Asteroids and Meteoroids -- A Wide Field Survey) systems to be built around the world.

  13. Automatic Detection of Asteroids and Meteoroids - A Wide Field Survey

    CERN Document Server

    Vereš, P; Jedicke, R; Tonry, J; Denneau, L; Wainscoat, R; Kornoš, L; Šilha, J

    2014-01-01

    We propose a low-cost robotic optical survey aimed at $1-300$ m Near Earth Objects (NEO) based on four state-of-the-art telescopes having extremely wide field of view. The small Near-Earth Asteroids (NEA) represent a potential risk but also easily accessible space resources for future robotic or human space in-situ exploration, or commercial activities. The survey system will be optimized for the detection of fast moving - trailed - asteroids, space debris and will provide real-time alert notifications. The expected cost of the system including 1-year development and 2-year operation is 1,000,000 EUR. The successful demonstration of the system will promote cost-efficient ADAM-WFS (Automatic Detection of Asteroids and Meteoroids - A Wide Field Survey) systems to be built around the world.

  14. The Teide Observatory Tenerife Asteroid Survey

    Science.gov (United States)

    Koschny, D.; Busch, M.

    2015-12-01

    ESA's 1-m telescope on Tenerife, the Optical Ground Station (OGS), has been used for observing NEOs since 2009. Part of the observational activity is the demonstration and test of survey observation strategies. During the observations, a total of 11 near-Earth objects have been discovered in about 360 h of observing time from 2009 to 2014. The survey observations are performed by imaging the same area in the sky 3 or 4 times within a 15-20 min time interval. A software robot analyses the images, searching for moving objects. The survey strategies and related data processing algorithms are described in this paper.

  15. ASTEROIDS

    OpenAIRE

    Željko Andreić

    2016-01-01

    Asteroids are the largest minor bodies in the Solar System. Nowadays they are in the research focus due to several facts about them: first, a subclass of asteroids can collide with Earth, and consequences of such a collision are dramatic. Second, they are now seen as source of materials that are becoming scarce on Earth, and they will be needed in future space constructions anyway. Third, they are holding clues about the origin and evolution of the Solar System. In this article, a short overv...

  16. Asteroid Discovery and Characterization with the Large Synoptic Survey Telescope (LSST)

    CERN Document Server

    Jones, R Lynne; Ivezic, Zeljko

    2015-01-01

    The Large Synoptic Survey Telescope (LSST) will be a ground-based, optical, all-sky, rapid cadence survey project with tremendous potential for discovering and characterizing asteroids. With LSST's large 6.5m diameter primary mirror, a wide 9.6 square degree field of view 3.2 Gigapixel camera, and rapid observational cadence, LSST will discover more than 5 million asteroids over its ten year survey lifetime. With a single visit limiting magnitude of 24.5 in r-band, LSST will be able to detect asteroids in the Main Belt down to sub-kilometer sizes. The current strawman for the LSST survey strategy is to obtain two visits (each visit being a pair of back-to-back 15s exposures) per field, separated by about 30 minutes, covering the entire visible sky every 3-4 days throughout the observing season, for ten years. The catalogs generated by LSST will increase the known number of small bodies in the Solar System by a factor of 10-100 times, among all populations. The median number of observations for Main Belt aster...

  17. Polarimetric survey of main-belt asteroids. V. The unusual polarimetric behavior of V-type asteroids

    Science.gov (United States)

    Gil-Hutton, R.; López-Sisterna, C.; Calandra, M. F.

    2017-03-01

    Aims: We present the results of a polarimetric survey of main-belt asteroids at Complejo Astronómico El Leoncito (CASLEO), San Juan, Argentina. The aims of this survey are to increase the database of asteroid polarimetry, to estimate diversity in polarimetric properties of asteroids that belong to different taxonomic classes, and to search for objects that exhibit anomalous polarimetric properties. Methods: The data were obtained using the CASPROF and CASPOL polarimeters at the 2.15 m telescope. The CASPROF polarimeter is a two-hole aperture polarimeter with rapid modulation and CASPOL is a polarimeter based on a CCD detector, which allows us to observe fainter objects with better signal-to-noise ratio. Results: The survey began in 1995 and data on a large sample of asteroids were obtained until 2012. A second period began in 2013 using a polarimeter with a more sensitive detector in order to study small asteroids, families, and special taxonomic groups. We obtained 55 polarimetric measurements for 28 V-type main belt asteroids, all of them polarimetrically observed for the first time. The data obtained in this survey let us find polarimetric parameters for (1459) Magnya and for a group of 11 small V-type objects with similar polarimetric behavior. These polarization curves are unusual since they show a shallow minimum and a small inversion angle in comparison with (4) Vesta, although they have a steeper slope at α0. This polarimetric behavior could be explained by differences in the regoliths of these asteroids. The observations of (2579) Spartacus, and perhaps also (3944) Halliday, indicate a inversion angle larger than 24-25°. Based on observations carried out at the Complejo Astronómico El Leoncito, operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba, and San Juan.

  18. AcuA: the AKARI/IRC Mid-infrared Asteroid Survey

    CERN Document Server

    Usui, Fumihiko; Mueller, Thomas G; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; Ishihara, Daisuke; Kataza, Hirokazu; Takita, Satoshi; Oyabu, Shinki; Ueno, Munetaka; Matsuhara, Hideo; Onaka, Takashi

    2011-01-01

    We present the results of an unbiased asteroid survey in the mid-infrared wavelength with the Infrared Camera (IRC) onboard the Japanese infrared satellite AKARI. About 20% of the point source events recorded in the AKARI All-Sky Survey observations are not used for the IRC Point Source Catalog (IRC-PSC) in its production process because of the lack of multiple detection by position. Asteroids, which are moving objects on the celestial sphere, remain in these "residual events". We identify asteroids out of the residual events by matching them with the positions of known asteroids. For the identified asteroids, we calculate the size and albedo based on the Standard Thermal Model. Finally we have a brand-new catalog of asteroids, named the Asteroid Catalog Using Akari (AcuA), which contains 5,120 objects, about twice as many as the IRAS asteroid catalog. The catalog objects comprise 4,953 main belt asteroids, 58 near Earth asteroids, and 109 Jovian Trojan asteroids. The catalog will be publicly available via th...

  19. Medicare Current Beneficiary Survey

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Characteristics and Perceptions of the Medicare Population Data from the 2010 Medicare Current Beneficiary Survey is a series of source books based on the...

  20. Lightcurve Survey of V-type Asteroids in the Inner Asteroid Belt

    CERN Document Server

    Hasegawa, Sunao; Mito, Hiroyuki; Sarugaku, Yuki; Ozawa, Tomohiko; Kuroda, Daisuke; Nishihara, Setsuko; Harada, Akari; Yoshida, Michitoshi; Yanagisawa, Kenshi; Shimizu, Yasuhiro; Nagayama, Shogo; Toda, Hiroyuki; Okita, Kouji; Kawai, Nobuyuki; Mori, Machiko; Sekiguchi, Tomohiko; Ishiguro, Masateru; Abe, Takumi; Abe, Masanao

    2013-01-01

    We have observed the lightcurves of 13 V-type asteroids ((1933) Tinchen, (2011) Veteraniya, (2508) Alupka, (3657) Ermolova, (3900) Knezevic, (4005) Dyagilev, (4383) Suruga, (4434) Nikulin, (4796) Lewis, (6331) 1992 $\\mathrm{FZ_{1}}$, (8645) 1998 TN, (10285) Renemichelsen, and (10320) Reiland). Using these observations we determined the rotational rates of the asteroids, with the exception of Nikulin and Renemichelsen. The distribution of rotational rates of 59 V-type asteroids in the inner main belt, including 29 members of the Vesta family that are regarded as ejecta from the asteroid (4) Vesta, is inconsistent with the best-fit Maxwellian distribution. This inconsistency may be due to the effect of thermal radiation Yarkovsky--O'Keefe--Radzievskii--Paddack (YORP) torques, and implies that the collision event that formed V-type asteroids is sub-billion to several billion years in age.

  1. Bulk Densities of Binary Asteroids from the Warm Spitzer NEO Survey

    NARCIS (Netherlands)

    Kistler, John; Trilling, D. E.; Mueller, M.; Hora, J. L.; Harris, A. W.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Emery, J. P.; Fazo, G.; Mainzer, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.; Thomas, C. A.

    2010-01-01

    The Warm Spitzer NEO survey, ExploreNEOs, will observe approximately 700 Near Earth Asteroids. Several of these objects are known to be binary asteroid systems. Binary systems are interesting due to the unique opportunity they present for determining the masses and densities of their constituent bod

  2. The taxonomic distribution of asteroids from multi-filter all-sky photometric surveys

    Science.gov (United States)

    DeMeo, F. E.; Carry, B.

    2013-09-01

    The distribution of asteroids across the main belt has been studied for decades to understand the current compositional distribution and what that tells us about the formation and evolution of our Solar System. All-sky surveys now provide orders of magnitude more data than targeted surveys. We present a method to bias-correct the asteroid population observed in the Sloan Digital Sky Survey (SDSS) according to size, distance, and albedo. We taxonomically classify this dataset consistent with the Bus and Binzel (Bus, S.J., Binzel, R.P. [2002]. Icarus 158, 146-177) and Bus-DeMeo et al. (DeMeo, F.E., Binzel, R.P., Slivan, S.M., Bus, S.J. [2009]. Icarus 202(July), 160-180) systems and present the resulting taxonomic distribution. The dataset includes asteroids as small as 5 km, a factor of three in diameter smaller than in previous work such as by Mothé-Diniz et al. (Mothé-Diniz, T., Carvano, J.M.Á., Lazzaro, D. [2003]. Icarus 162(March), 10-21). Because of the wide range of sizes in our sample, we present the distribution by number, surface area, volume, and mass whereas previous work was exclusively by number. While the distribution by number is a useful quantity and has been used for decades, these additional quantities provide new insights into the distribution of total material. We find evidence for D-types in the inner main belt where they are unexpected according to dynamical models of implantation of bodies from the outer Solar System into the inner Solar System during planetary migration (Levison, H.F., Bottke, W.F., Gounelle, M., Morbidelli, A., Nesvorný, D., Tsiganis, K. [2009]. Nature 460(July), 364-366). We find no evidence of S-types or other unexpected classes among Trojans and Hildas, albeit a bias favoring such a detection. Finally, we estimate for the first time the total amount of material of each class in the inner Solar System. The main belt’s most massive classes are C, B, P, V and S in decreasing order. Excluding the four most massive

  3. Statistical analysis of the astrometric errors for the most productive asteroid surveys

    Science.gov (United States)

    Vereš, Peter; Farnocchia, Davide; Chesley, Steven R.; Chamberlin, Alan

    2016-10-01

    Accurate orbits of minor planets allow reliable predictions of an object's location in time and space. High fidelity ephemerides are crucial for the space missions targeting asteroids and comets, mitigation of Earth impact hazard, study of non-gravitational effects on small bodies and mass determination of encountering objects through mutual perturbations. The length of the observation arc as well as high quality astrometry play an essential role in achieving accurate orbits. In particular, accurate astrometry can allow the recovery of small near-Earth objects that could otherwise be lost. The vast majority of the 715,000 known asteroids have been discovered and observed by major dedicated optical CCD surveys. However, uncertainties of individual astrometric positions are not directly provided by observers yet and so orbit determination traditionally relies on conservative estimates of astrometric errors. We present a statistical study of astrometric residuals of optical CCD astrometry for the nine most prolific past and current asteroid surveys: Pan-STARRS1 (F51), Mt. Lemmon (G96), Catalina (703), LINEAR (704), Spacewatch (691), LONEOS (699), NEAT (644), NEOWISE (C51) and SST (G45). The study was limited to multiple apparition asteroids, which have well-constrained orbits, after correcting for the star catalog position and proper motion biases (Farnocchia et al., 2015). Therefore, the resulting astrometric residuals can be largely attributed to astrometric and timing errors in the reported astrometry. We analyze the behavior of residuals in right ascension, declination, along-track and cross-track, as well as timing errors. Astrometric residuals generally depend on reported magnitude by a quadratic function with astrometric quality degradation near the limiting magnitude and the saturation limit for bright objects. We found no systematic timing errors exceeding one second for the tested surveys. The presented analysis provides useful information to improve the

  4. Near-Earth-object survey progress and population of small near-Earth asteroids

    Science.gov (United States)

    Harris, A.

    2014-07-01

    Estimating the total population vs. size of NEAs and the completion of surveys is the same thing since the total population is just the number discovered divided by the estimated completion. I review the method of completion estimation based on ratio of re-detected objects to total detections (known plus new discoveries). The method is quite general and can be used for population estimations of all sorts, from wildlife to various classes of solar system bodies. Since 2001, I have been making estimates of population and survey progress approximately every two years. Plotted below, left, is my latest estimate, including NEA discoveries up to August, 2012. I plan to present an update at the meeting. All asteroids of a given size are not equally easy to detect because of specific orbital geometries. Thus a model of the orbital distribution is necessary, and computer simulations using those orbits need to establish the relation between the raw re-detection ratio and the actual completion fraction. This can be done for any sub-group population, allowing to estimate the population of a subgroup and the expected current completion. Once a reliable survey computer model has been developed and ''calibrated'' with respect to actual survey re-detections versus size, it can be extrapolated to smaller sizes to estimate completion even at very small size where re-detections are rare or even zero. I have recently investigated the subgroup of extremely low encounter velocity NEAs, the class of interest for the Asteroid Redirect Mission (ARM), recently proposed by NASA. I found that asteroids of diameter ˜ 10 m with encounter velocity with the Earth lower than 2.5 km/sec are detected by current surveys nearly 1,000 times more efficiently than the general background of NEAs of that size. Thus the current completion of these slow relative velocity objects may be around 1%, compared to 10^{-6} for that size objects of the general velocity distribution. Current surveys are nowhere near

  5. The EURONEAR Lightcurve Survey of Near Earth Asteroids

    Science.gov (United States)

    Vaduvescu, O.; Aznar Macias, A.; Tudor, V.; Predatu, M.; Galád, A.; Gajdoš, Š.; Világi, J.; Stevance, H. F.; Errmann, R.; Unda-Sanzana, E.; Char, F.; Peixinho, N.; Popescu, M.; Sonka, A.; Cornea, R.; Suciu, O.; Toma, R.; Santos-Sanz, P.; Sota, A.; Licandro, J.; Serra-Ricart, M.; Morate, D.; Mocnik, T.; Diaz Alfaro, M.; Lopez-Martinez, F.; McCormac, J.; Humphries, N.

    2017-07-01

    This data paper presents lightcurves of 101 near Earth asteroids (NEAs) observed mostly between 2014 and 2017 as part of the EURONEAR photometric survey using 11 telescopes with diameters between 0.4 and 4.2 m located in Spain, Chile, Slovakia and Romania. Most targets had no published data at the time of observing, but some objects were observed in the same period mainly by B. Warner, allowing us to confirm or improve the existing results. To plan the runs and select the targets, we developed the public Long Planning tool in PHP. For preliminary data reduction and rapid follow-up planning we developed the LiDAS pipeline in Python and IRAF. For final data reduction, flux calibration, night linkage and Fourier fitting, we used mainly MPO Canopus. Periods of 18 targets are presented for the first time, and we could solve or constrain rotation for 16 of them. We secured periods for 45 targets (U˜ 3 ), found candidate periods for other 16 targets (U˜ 2 ), and we propose tentative periods for other 32 targets (U˜ 1 ). We observed 7 known or candidate binary NEAs, fiting 3 of them (2102 Tantalus, 5143 Heracles and 68348). We observed 8 known or candidate tumbling NEAs, deriving primary periods for 3 objects (9400, 242708 and 470510). We evidenced rapid oscillations (few minutes) and could fit fast tentative periods TP2 for 5 large newly suggested tumbling or binary candidates (27346, 112985, 285625, 377732, 408980), probably discovering at least one new binary NEA (2011 WO41). We resolved periods of 4 special objects which include two proposed space mission targets (163249 and 101955 Bennu), one very fast rotator NEA discovered by EURONEAR (2014 NL52) and the "Halloween asteroid" (2015 TB145). Using Mercator in simultaneous 3 band MAIA imaging, we could evidence for the first time clear variation in the color lightcurves of 10 NEAs. The periods derived from the g-r color lightcurves are found to match individual band period fits for 4 NEAs (27346, 86067, 112985 and

  6. The EURONEAR Lightcurve Survey of Near Earth Asteroids

    Science.gov (United States)

    Vaduvescu, O.; Macias, A. Aznar; Tudor, V.; Predatu, M.; Galád, A.; Gajdoš, Š.; Világi, J.; Stevance, H. F.; Errmann, R.; Unda-Sanzana, E.; Char, F.; Peixinho, N.; Popescu, M.; Sonka, A.; Cornea, R.; Suciu, O.; Toma, R.; Santos-Sanz, P.; Sota, A.; Licandro, J.; Serra-Ricart, M.; Morate, D.; Mocnik, T.; Alfaro, M. Diaz; Lopez-Martinez, F.; McCormac, J.; Humphries, N.

    2017-08-01

    This data paper presents lightcurves of 101 near Earth asteroids (NEAs) observed mostly between 2014 and 2017 as part of the EURONEAR photometric survey using 11 telescopes with diameters between 0.4 and 4.2 m located in Spain, Chile, Slovakia and Romania. Most targets had no published data at the time of observing, but some objects were observed in the same period mainly by B. Warner, allowing us to confirm or improve the existing results. To plan the runs and select the targets, we developed the public Long Planning tool in PHP. For preliminary data reduction and rapid follow-up planning we developed the LiDAS pipeline in Python and IRAF. For final data reduction, flux calibration, night linkage and Fourier fitting, we used mainly MPO Canopus. Periods of 18 targets are presented for the first time, and we could solve or constrain rotation for 16 of them. We secured periods for 45 targets (U˜ 3), found candidate periods for other 16 targets (U˜ 2), and we propose tentative periods for other 32 targets (U˜ 1). We observed 7 known or candidate binary NEAs, fiting 3 of them (2102 Tantalus, 5143 Heracles and 68348). We observed 8 known or candidate tumbling NEAs, deriving primary periods for 3 objects (9400, 242708 and 470510). We evidenced rapid oscillations (few minutes) and could fit fast tentative periods TP2 for 5 large newly suggested tumbling or binary candidates (27346, 112985, 285625, 377732, 408980), probably discovering at least one new binary NEA (2011 WO41). We resolved periods of 4 special objects which include two proposed space mission targets (163249 and 101955 Bennu), one very fast rotator NEA discovered by EURONEAR (2014 NL52) and the "Halloween asteroid" (2015 TB145). Using Mercator in simultaneous 3 band MAIA imaging, we could evidence for the first time clear variation in the color lightcurves of 10 NEAs. The periods derived from the g- r color lightcurves are found to match individual band period fits for 4 NEAs (27346, 86067, 112985 and

  7. Automatic detection of asteroids and meteoroids --- a wide-field survey

    Science.gov (United States)

    Vereš, P.; Tóth, J.; Jedicke, R.; Tonry, J.; Denneau, L.; Wainscoat, R.; Kornoš, L.; Šilha, J.

    2014-07-01

    The small Near-Earth Asteroids (NEAs) represent a potential risk but also an easily accessible space resource for future robotic or human in-situ space exploration or commercial activities. However, the population of 1--300 m NEAs is not well understood in terms of size- frequency and orbital distribution. NEAs with diameters below 200 m tend to have much faster spin rates than large objects and they are believed to be monolithic and not rubble-pile like their large counterparts. Moreover, the current surveys do not systematically search for the small NEAs that are mostly overlooked. We propose a low- cost robotic optical survey (ADAM-WFS) aimed at small NEAs based on four state-of-the-art telescopes having extremely wide fields of view. The four Houghton-Terebizh 30-cm astrographs (Fig. left) with 4096×4096 -pixel CCD cameras will acquire 96 square degrees in one exposure with the plate scale of 4.4 arcsec/pixel. In 30 seconds, the system will be able to reach +17.5 mag in unfiltered mode. The survey will be operated on semi-automatic basis, covering the entire night sky three times per night and optimized toward fast moving targets recognition. The advantage of the proposed system is the usage of existing of-the-shelf components and software for the image processing and object identification and linking (Denneau et al., 2013). The one-year simulation of the survey (Fig. right) at the testing location at AGO Modra observatory in Slovakia revealed that we will detect 60--240 NEAs between 1--300 m that get closer than 10 lunar distances from the Earth. The number of detections will rise by a factor of 1.5--2 in case the survey is placed at a superb observing location such as Canary Islands. The survey will also serve as an impact warning system for imminent impactors. Our simulation showed that we have a 20 % chance of finding a 50-m NEA on a direct impact orbit. The survey will provide multiple byproducts from the all-sky scans, such as comet discoveries, sparse

  8. Asteroid phase curve analysis with the H, G 1, G 2 photometric phase function: application to the PTF survey observations

    Science.gov (United States)

    Penttilä, Antti; Cellino, Alberto; Lu, Xiaoping; Shevchenko, Vasilij G.; Muinonen, Karri

    2016-10-01

    Estimation of an asteroid's absolute magnitude H from its photometry is extremely important. The absolute magnitude relates the brightness of the asteroid to its size, if the geometric albedo is known. The shape of the phase curve can serve as a proxy for the taxonomic type of the asteroid in cases with no spectral information available [1,2].In 2012, the IAU adopted the H,G1,G2 function to replace the H,G function for phase curve analysis [3]. This new function improves the backscattering behavior of the curve with high- and low-albedo asteroids. The phase function (PF) can be applied to asteroids with multiple high-quality observations. If the number of observations is small, or their accuracy is low, problems may arise. The most apparent problem is that the parameter G or the parameters G1, G2 might be poorly estimated. The solution has been to fix to value of G or values of G1, G2 and estimate only the H. In our recent work [4], we offer a solution that can improve the current situation with the photometric fits with a small number of low-accuracy observations. We present a constrained nonlinear least-squares method for fitting the H,G1,G2 function that can improve the possible bias with low-accuracy data. Then, we revisit the two-parameter PF with new data and offer a new version, the H,G12* PF. Finally, we assess the problem with fixed G or G1, G2 parameters by introducing one-parameter models that relate to five taxonomic asteroid groups. We tie all the models together with three or two parameters, or a single parameter, with a statistical model selection procedure to select the best version for a particular data set.We have developed practical tools for the abovementioned algorithms. We apply the tools to a dataset of 8,900 asteroids with almost 500,000 photometric observations from the Palomar Transient Factory survey [5]. We report the effect of the revised H estimates on the geometric albedos in cases where WISE-mission size estimates are available.[1] D

  9. Galactic Archaeology: Current Surveys

    CERN Document Server

    Wyse, Rosemary F G

    2016-01-01

    I present an overview of the science goals and achievements of ongoing spectroscopic surveys of individual stars in the nearby Universe. I include a brief discussion of the development of the field of Galactic Archaeology - using the fossil record in old stars nearby to infer how our Galaxy evolved and place the Milky Way in cosmological context.

  10. Searching for a Differentiated Asteroid Family: A Spectral Survey of the Massalia, Merxia, and Agnia Families

    Science.gov (United States)

    Thomas, Cristina A.; Lim, Lucy; Moskovitz, Nicholas; Trilling, David

    2015-11-01

    Asteroid families were formed by catastrophic collisions or large cratering events that caused fragmentation of the parent body and ejection of asteroidal fragments with velocities sufficient to prevent re-accretion. Due to these formation processes, asteroid families should provide us with the opportunity to probe the interiors of the former parent bodies. Differentiation of a large initially chondritic parent body is expected to result in an "onion shell" object with an iron-nickel core, a thick olivine-dominated mantle, and a thin plagioclase/pyroxene crust. However, most asteroid families tend to show similar spectra (and therefore composition) among the members. Spectroscopic studies have observed a paucity of metal-like materials and olivine-dominated assemblages within the Main Belt asteroid families.The deficit of olivine-rich mantle material in the meteorite record and in asteroid observations is known as the "Missing Mantle" problem. For years the best explanation has been the "battered to bits" hypothesis: that all differentiated parent bodies (aside from Vesta) were disrupted very early in the Solar System and the resulting olivine-rich material was collisionally broken down over time until the object diameters fell below our observational limits. In a competing hypothesis, Elkins-Tanton et al. (2013) have suggested that previous work has overestimated the amount of olivine produced by the differentiation of a chondritic parent body.We are conducting a visible and near-infrared wavelength spectral survey of asteroids in the Massalia, Merxia, and Agnia S-type Main Belt asteroid families. These families were carefully chosen for the proposed spectroscopic survey because they have compositions most closely associated with a history of thermal metamorphism and because they represent a range of collisional formation scenarios. In addition, the relatively young ages (under 400 Myr) of these families permit testing of the “battering to bits'' timescale. We

  11. The taxonomic distribution of asteroids from multi-filter all-sky photometric surveys

    CERN Document Server

    DeMeo, Francesca

    2013-01-01

    The distribution of asteroids across the Main Belt has been studied for decades to understand the compositional distribution and what that tells us about the formation and evolution of our solar system. All-sky surveys now provide orders of magnitude more data than targeted surveys. We present a method to bias-correct the asteroid population observed in the Sloan Digital Sky Survey (SDSS) according to size, distance, and albedo. We taxonomically classify this dataset consistent with the Bus and Bus-DeMeo systems and present the resulting taxonomic distribution. The dataset includes asteroids as small as 5 km, a factor of three in diameter smaller than in previous works. Because of the wide range of sizes in our sample, we present the distribution by number, surface area, volume, and mass whereas previous work was exclusively by number. While the distribution by number is a useful quantity and has been used for decades, these additional quantities provide new insights into the distribution of total material. W...

  12. Current problems of dynamics of moons of planets and binary asteroids based on observations

    Science.gov (United States)

    Emel'yanov, N. V.

    2017-01-01

    The general approach to studying the dynamics of moons of planets and asteroids consists in developing more and more accurate models of motion based on observational data. Not only the necessary ephemerides, but also some physical parameters of planets and moons are obtained this way. It is demonstrated in the present study that progress in this field is driven not only by the increase in accuracy of observations. The accuracy of ephemerides may be increased by expanding the observation time interval. Several problems arise on the way toward this goal. Some of them become apparent only when the procedure of observational data processing and use is examined in detail. The method used to derive astrometric data by processing the results of photometric observations of mutual occultations and eclipses of planetary moons is explained below. The primary contribution to the error of astrometric results is produced by the unaccounted noise level in photometric readings and the inaccuracy of received values of the albedo of moons. It is demonstrated that the current methods do not allow one to eliminate the noise completely. Extensive additional photometric measurements should be performed at different angles of rotation of moons and in different spectral bands of the visible wavelength range in order to obtain correct values of the albedo of moons. Many new distant moons of the major planets have been discovered in the early 21st century. However, the observations of these moons are scarce and were performed over short time intervals; as a result, some of the moons were lost. The necessity of further observations of these Solar System bodies is pointed out in the present study. Insufficient knowledge of asteroid masses is an obstacle to improving the accuracy of the ephemerides of Mars. The basic method for determining the masses of large asteroids consists in analyzing their influence on the motion of Mars, the Earth, and spacecraft. The masses of more than 100 large

  13. SURVEY SIMULATIONS OF A NEW NEAR-EARTH ASTEROID DETECTION SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Mainzer, A.; Bauer, J.; Giorgini, J.; Masiero, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ (United States); Conrow, T.; Cutri, R. M.; Dailey, J.; Fowler, J.; Jarrett, T. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Spahr, T. [Minor Planet Center, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street MS-18, Cambridge, MA 02138 (United States); Statler, T. [Astrophysical Institute, Ohio University (United States); Wright, E. L. [Department of Astronomy and Astrophysics, University of California Los Angeles, Los Angeles, CA (United States)

    2015-05-15

    We have carried out simulations to predict the performance of a new space-based telescopic survey operating at thermal infrared wavelengths that seeks to discover and characterize a large fraction of the potentially hazardous near-Earth asteroid (NEA) population. Two potential architectures for the survey were considered: one located at the Earth–Sun L1 Lagrange point, and one in a Venus-trailing orbit. A sample cadence was formulated and tested, allowing for the self-follow-up necessary for objects discovered in the daytime sky on Earth. Synthetic populations of NEAs with sizes as small as 140 m in effective spherical diameter were simulated using recent determinations of their physical and orbital properties. Estimates of the instrumental sensitivity, integration times, and slew speeds were included for both architectures assuming the properties of newly developed large-format 10 μm HgCdTe detector arrays capable of operating at ∼35 K. Our simulation included the creation of a preliminary version of a moving object processing pipeline suitable for operating on the trial cadence. We tested this pipeline on a simulated sky populated with astrophysical sources such as stars and galaxies extrapolated from Spitzer Space Telescope and Wide-field Infrared Explorer data, the catalog of known minor planets (including Main Belt asteroids, comets, Jovian Trojans, planets, etc.), and the synthetic NEA model. Trial orbits were computed for simulated position-time pairs extracted from the synthetic surveys to verify that the tested cadence would result in orbits suitable for recovering objects at a later time. Our results indicate that the Earth–Sun L1 and Venus-trailing surveys achieve similar levels of integral completeness for potentially hazardous asteroids larger than 140 m; placing the telescope in an interior orbit does not yield an improvement in discovery rates. This work serves as a necessary first step for the detailed planning of a next-generation NEA survey.

  14. On Identifying Clusters Within the C-type Asteroids of the Sloan Digital Sky Survey

    Science.gov (United States)

    Poole, Renae; Ziffer, J.; Harvell, T.

    2012-10-01

    We applied AutoClass, a data mining technique based upon Bayesian Classification, to C-group asteroid colors in the Sloan Digital Sky Survey (SDSS). Previous taxonomic studies relied mostly on Principal Component Analysis (PCA) to differentiate asteroids within the C-group (e.g. B, G, F, Ch, Cg and Cb). AutoClass's advantage is that it calculates the most probable classification for us, removing the human factor from this part of the analysis. In our results, AutoClass divided the C-groups into two large classes and six smaller classes. The two large classes (n=4974 and 2033, respectively) display distinct regions with some overlap in color-vs-color plots. Each cluster's average spectrum is compared to 'typical' spectra of the C-group subtypes as defined by Tholen (1989) and each cluster's members are evaluated for consistency with previous taxonomies. Of the 117 asteroids classified as B-type in previous taxonomies, only 12 were found with SDSS colors that matched our criteria of having less than 0.1 magnitude error in u and 0.05 magnitude error in g, r, i, and z colors. Although this is a relatively small group, 11 of the 12 B-types were placed by AutoClass in the same cluster. By determining the C-group sub-classifications in the large SDSS database, this research furthers our understanding of the stratigraphy and composition of the main-belt.

  15. Small Near-Earth Asteroids in the Palomar Transient Factory Survey: A Real-Time Streak-detection System

    Science.gov (United States)

    Waszczak, Adam; Prince, Thomas A.; Laher, Russ; Masci, Frank; Bue, Brian; Rebbapragada, Umaa; Barlow, Tom; Surace, Jason; Helou, George; Kulkarni, Shrinivas

    2017-03-01

    Near-Earth asteroids (NEAs) in the 1–100 meter size range are estimated to be ∼1,000 times more numerous than the ∼15,000 currently cataloged NEAs, most of which are in the 0.5–10 kilometer size range. Impacts from 10–100 meter size NEAs are not statistically life-threatening, but may cause significant regional damage, while 1–10 meter size NEAs with low velocities relative to Earth are compelling targets for space missions. We describe the implementation and initial results of a real-time NEA-discovery system specialized for the detection of small, high angular rate (visually streaked) NEAs in Palomar Transient Factory (PTF) images. PTF is a 1.2-m aperture, 7.3 deg2 field of view (FOV) optical survey designed primarily for the discovery of extragalactic transients (e.g., supernovae) in 60-second exposures reaching ∼20.5 visual magnitude. Our real-time NEA discovery pipeline uses a machine-learned classifier to filter a large number of false-positive streak detections, permitting a human scanner to efficiently and remotely identify real asteroid streaks during the night. Upon recognition of a streaked NEA detection (typically within an hour of the discovery exposure), the scanner triggers follow-up with the same telescope and posts the observations to the Minor Planet Center for worldwide confirmation. We describe our 11 initial confirmed discoveries, all small NEAs that passed 0.3–15 lunar distances from Earth. Lastly, we derive useful scaling laws for comparing streaked-NEA-detection capabilities of different surveys as a function of their hardware and survey-pattern characteristics. This work most directly informs estimates of the streak-detection capabilities of the Zwicky Transient Facility (ZTF, planned to succeed PTF in 2017), which will apply PTF’s current resolution and sensitivity over a 47-deg2 FOV.

  16. Investigating the composition of Potentially Hazardous Asteroids with the NEO-SURFACE survey

    Science.gov (United States)

    Ieva, S.; Dotto, E.; Perna, D.; Barucci, M. A.; Bernardi, F.; Perozzi, E.; Micheli, M.; Mazzotta Epifani, E.; Brucato, J. R.; Fornasier, S.; De Luise, F.; Rossi, A.

    2015-10-01

    There is a high degree of diversity among the physical properties of the Potentially Hazardous asteroids (PHAs). For these objects, the physical characterization is essential to define a successful mitigation mission, therefore ground-based surveys like NEO-SURFACE could provide a fundamental contribution. Our analysis suggest a prevalence of silicate S-types in the PHA population, which could be due in principle to the high efficiency of the transport mechanisms in the inner main belt, or to an observational bias due to the fact that S-types are brighter.

  17. Survey Simulations of an New Near-Earth Asteroid Detection System

    CERN Document Server

    Mainzer, A; Bauer, J; Conrow, T; Cutri, R M; Dailey, J; Fowler, J; Giorgini, J; Jarrett, T; Masiero, J; Spahr, T; Statler, T; Wright, E L

    2015-01-01

    We have carried out simulations to predict the performance of a new space-based telescopic survey operating at thermal infrared wavelengths that seeks to discover and characterize a large fraction of the potentially hazardous near-Earth asteroid (NEA) population. Two potential architectures for the survey were considered: one located at the Earth-Sun L1 Lagrange point, and one in a Venus-trailing orbit. A sample cadence was formulated and tested, allowing for the self-follow-up necessary for objects discovered in the daytime sky on Earth. Synthetic populations of NEAs with sizes >=140 m in effective spherical diameter were simulated using recent determinations of their physical and orbital properties. Estimates of the instrumental sensitivity, integration times, and slew speeds were included for both architectures assuming the properties of new large-format 10 um detector arrays capable of operating at ~35 K. Our simulation included the creation of a preliminary version of a moving object processing pipeline ...

  18. ASPIN-ISON asteroid program: History, current state, and future prospects

    Science.gov (United States)

    Elenin, L.; Molotov, I.; Savanevych, V.; Krugly, Y.; Bruhovetskiy, A.; Ivaschenko, Y.

    2014-07-01

    ASPIN - ISON asteroid program started in Sept.~2003 at Andrushivka observatory (Ukraine) [1]. For these purposes, a Zeiss-600 telescope with small CCD camera was used. In 2009, the telescope was upgraded by a full-format CCD camera and a lens corrector, increasing the FOV to 72'x72'. During the first 7 years, the observatory discovered more than 350 asteroids, inc.~2 NEAs. Unfortunately, at present time, when the rivalry of surveys is growing up, Andrushivka was forced to stop the observations in 2013, due to the bad astroclimate and, as a result, the low magnitude limit. In 2014, we are planning to install a new, wide-field ORI-50M (0.5-m f/2.3) telescope at a new site with good astroclimate conditions. After that, the survey program will resume. The next ISON observatory, which started its own survey, was ISON-NM (Mayhill, NM, USA). The survey work started in July 2010 and continues to this day. The first telescope of this observatory was Centurion-18, 0.45-m f/2.8 with full-frame CCD camera. In Sept.~2013, the telescope was replaced by our new telescope Santel-400AN (0.4-m f/3) with 105'x105' FOV. Both telescopes were controlled remotely from Moscow. At ISON-NM, more than 1,400 asteroids were discovered, including 4 NEOs and 2 comets: the well-known C/2010 X1 (Elenin)[2], P/2011 NO1 (Elenin)[3]. More than 450,000 observations of small bodies were obtained. Except survey work, ISON-NM carries out photometric observations of NEAs: it has obtained dozens of lightcurves, determining the rotation period for more than 20 NEAs, including extremely close and fast rotators, such as 2012 KP24, 2012 KT42, 2012 LZ1, and Duende (2012 DA14) [4]. Since April 2012, another observatory joined ASPIN - ISON-Kislovodsk (Kislovodsk, N. Caucasus, Russia). At the observatory, one (and first) of two Santel-400AN telescopes was installed with a full-frame CCD camera, providing a 105'x105' FOV. At present time, ISON-Kislovodsk is the second of all ASPIN observatories by the number of

  19. The Calern Asteroid Polarimetric Survey using the Torino polarimeter: assessment of instrument performances and first scientific results

    Science.gov (United States)

    Devogèle, M.; Cellino, A.; Bagnulo, S.; Rivet, J. P.; Bendjoya, P.; Abe, L.; Pernechele, C.; Massone, G.; Vernet, D.; Tanga, P.; Dimur, C.

    2017-03-01

    A new polarimeter based on the wedged double Wollaston concept has been built at the Torino Observatory and installed on a 1-m telescope at the Calern observing station of the Observatoire de la Côte d'Azur, France. Its main purpose is to carry out a polarimetric survey of minor Solar system objects, which is called the Calern Asteroid Polarimetric Survey. In this paper, we describe the new Torino polarimeter and the results of preliminary scientific validation tests. A number of standard stars with known polarization states, as well as a number of asteroids for which the polarimetric properties are known, have been observed in order to assess the instrument's accuracy. The instrumental polarization has been found to be stable within a few 10-4 units. A total of 124 new polarimetric observation of 78 asteroids are presented. In the case of asteroids already observed in the past, the new data are in agreement with available phase-polarization curves with error bars smaller than most previously published data. We also present data for 21 asteroids that have never been observed before in polarimetry.

  20. A fast method for quantifying observational selection effects in asteroid surveys

    Science.gov (United States)

    Jedicke, Robert; Bolin, Bryce; Granvik, Mikael; Beshore, Ed

    2016-03-01

    We present a fast method to calculate an asteroid survey's 'bias' - essentially a correction factor from the observed number of objects to the actual number in the population. The method builds upon the work of Jedicke and Metcalfe (Jedicke, R., Metcalfe, T.S. [1998]. Icaurs 131, 245-260) and Granvik et al. (Granvik, M., Vaubaillon, J., Jedicke, R. [2012]. Icarus 218, 262-277) and essentially efficiently maps out the phase space of orbit elements that can appear in a field-of-view. It does so by 'integrating' outwards in geocentric distance along a field's boresite from the topocentric location of the survey and calculating the allowable angular elements for each desired combination of semi-major axis, eccentricity and inclination. We then use a contour algorithm to map out the orbit elements that place an object at the edge of the field-of-view. We illustrate the method's application to calculate the bias correction for near Earth Objects detected with the Catalina Sky Survey (Christensen, E. et al. [2012]. AAS/Division for Planetary Sciences Meeting Abstracts, vol. 44, p. 210.13; Larson, S. et al. [1998]. Bulletin of the American Astronomical Society, vol. 30, p. 1037).

  1. Asteroids IV

    Science.gov (United States)

    Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

    Asteroids are fascinating worlds. Considered the building blocks of our planets, many of the authors of this book have devoted their scientific careers to exploring them with the tools of our trade: ground- and spacebased observations, in situ space missions, and studies that run the gamut from theoretical modeling efforts to laboratory work. Like fossils for paleontologists, or DNA for geneticists, they allow us to construct a veritable time machine and provide us with tantalizing glimpses of the earliest nature of our solar system. By investigating them, we can probe what our home system was like before life or even the planets existed. The origin and evolution of life on our planet is also intertwined with asteroids in a different way. It is believed that impacts on the primordial Earth may have delivered the basic components for life, with biology favoring attributes that could more easily survive the aftermath of such energetic events. In this fashion, asteroids may have banished many probable avenues for life to relative obscurity. Similarly, they may have also prevented our biosphere from becoming more complex until more recent eras. The full tale of asteroid impacts on the history of our world, and how human life managed to emerge from myriad possibilities, has yet to be fully told. The hazard posed by asteroid impacts to our civilization is low but singular. The design of efficient mitigation strategies strongly relies on asteroid detection by our ground- and spacebased surveys as well as knowledge of their physical properties. A more positive motivation for asteroid discovery is that the proximity of some asteroids to Earth may allow future astronauts to harvest their water and rare mineral resources for use in exploration. A key goal of asteroid science is therefore to learn how humans and robotic probes can interact with asteroids (and extract their materials) in an efficient way. We expect that these adventures may be commonplace in the future

  2. Medicare Current Beneficiary Survey - Limited Data Set

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medicare Current Beneficiary Survey (MCBS) is a continuous, multipurpose survey of a representative national sample of the Medicare population. There are two...

  3. Small near-Earth asteroids in the Palomar Transient Factory survey: A real-time streak-detection system

    CERN Document Server

    Waszczak, Adam; Laher, Russ; Masci, Frank; Bue, Brian; Rebbapragada, Umaa; Barlow, Tom; Surace, Jason; Helou, George; Kulkarni, Shrinivas

    2016-01-01

    Near-Earth asteroids (NEAs) in the 1-100 meter size range are estimated to be $\\sim$1,000 times more numerous than the $\\sim$15,000 currently-catalogued NEAs, most of which are in the 0.5-10 kilometer size range. Impacts from 10-100 meter size NEAs are not statistically life-threatening but may cause significant regional damage, while 1-10 meter size NEAs with low velocities relative to Earth are compelling targets for space missions. We describe the implementation and initial results of a real-time NEA-discovery system specialized for the detection of small, high angular rate (visually-streaked) NEAs in Palomar Transient Factory (PTF) images. PTF is a 1.2-m aperture, 7.3-deg$^2$ field-of-view optical survey designed primarily for the discovery of extragalactic transients (e.g., supernovae) in 60-second exposures reaching $\\sim$20.5 visual magnitude. Our real-time NEA discovery pipeline uses a machine-learned classifier to filter a large number of false-positive streak detections, permitting a human scanner t...

  4. Lightcurve Survey of V-type Asteroids. I. Observations until Spring 2004

    CERN Document Server

    Hasegawa, Sunao; Yoshizumi, Chiaki; Sekiguchi, Tomohiko; Sarugaku, Yuki; Nishihara, Setsuko; Kitazato, Kouhei; Abe, Masanao; Mito, Hiroyuki

    2012-01-01

    To examine the distribution of rotational rates for chips of asteroid 4 Vesta, lightcurve observation of seven V-type asteroids (2511 Patterson, 2640 Hallstorm, 2653 Principia, 2795 Lapage, 3307 Athabasca, 4147 Lennon, and 4977 Rauthgundis) were performed from fall 2003 to spring 2004. Distribution of spin rates of V-type main-belt asteroids from the past and our observations have three peaks. This result implies that age of catastrophic impact making Vesta family may be not as young as Karin and Iannini families but as old as Eos and Koronis families.

  5. Polarimetric survey of main-belt asteroids. II. Results for 58 B- and C-type objects

    Science.gov (United States)

    Gil-Hutton, R.; Cañada-Assandri, M.

    2012-03-01

    Aims: We present results of a polarimetric survey of main-belt asteroids at Complejo Astronómico el Leoncito (CASLEO), San Juan, Argentina. The aims of this survey are to increase the database of asteroid polarimetry, to estimate diversity in polarimetric properties of asteroids that belong to different taxonomic classes, and to search for objects that exhibit anomalous polarimetric properties. Methods: The data were obtained with the Torino and CASPROF polarimeters at the 2.15m telescope. The Torino polarimeter is an instrument that allows simultaneous measurement of polarization in five different bands, and the CASPROF polarimeter is a two-hole aperture polarimeter with rapid modulation. Results: The survey began in 2003, and up to 2009 data on a sample of more than 170 asteroids were obtained. In this paper the results for 58 B- and C-type objects are presented, most of them polarimetrically observed for the first time. Using these data we find phase-polarization curves and polarimetric parameters for these taxonomic classes. Based on observations carried out at the Complejo Astronómico El Leoncito, operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba, and San Juan.Tables 1 and 2 are available in electronic form at CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/539/A115

  6. ASTEROID LIGHT CURVES FROM THE PALOMAR TRANSIENT FACTORY SURVEY: ROTATION PERIODS AND PHASE FUNCTIONS FROM SPARSE PHOTOMETRY

    Energy Technology Data Exchange (ETDEWEB)

    Waszczak, Adam [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Chang, Chan-Kao; Cheng, Yu-Chi; Ip, Wing-Huen; Kinoshita, Daisuke [Institute of Astronomy, National Central University, Jhongli, Taiwan (China); Ofek, Eran O. [Benoziyo Center for Astrophysics, Weizmann Institute of Science, Rehovot (Israel); Laher, Russ; Surace, Jason [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Masci, Frank; Helou, George [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Levitan, David; Prince, Thomas A.; Kulkarni, Shrinivas, E-mail: waszczak@caltech.edu [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

    2015-09-15

    We fit 54,296 sparsely sampled asteroid light curves in the Palomar Transient Factory survey to a combined rotation plus phase-function model. Each light curve consists of 20 or more observations acquired in a single opposition. Using 805 asteroids in our sample that have reference periods in the literature, we find that the reliability of our fitted periods is a complicated function of the period, amplitude, apparent magnitude, and other light-curve attributes. Using the 805-asteroid ground-truth sample, we train an automated classifier to estimate (along with manual inspection) the validity of the remaining ∼53,000 fitted periods. By this method we find that 9033 of our light curves (of ∼8300 unique asteroids) have “reliable” periods. Subsequent consideration of asteroids with multiple light-curve fits indicates a 4% contamination in these “reliable” periods. For 3902 light curves with sufficient phase-angle coverage and either a reliable fit period or low amplitude, we examine the distribution of several phase-function parameters, none of which are bimodal though all correlate with the bond albedo and with visible-band colors. Comparing the theoretical maximal spin rate of a fluid body with our amplitude versus spin-rate distribution suggests that, if held together only by self-gravity, most asteroids are in general less dense than ∼2 g cm{sup −3}, while C types have a lower limit of between 1 and 2 g cm{sup −3}. These results are in agreement with previous density estimates. For 5–20 km diameters, S types rotate faster and have lower amplitudes than C types. If both populations share the same angular momentum, this may indicate the two types’ differing ability to deform under rotational stress. Lastly, we compare our absolute magnitudes (and apparent-magnitude residuals) to those of the Minor Planet Center’s nominal (G = 0.15, rotation-neglecting) model; our phase-function plus Fourier-series fitting reduces asteroid photometric rms

  7. AVAST Survey 0.4-1.0 {\\mu}m Spectroscopy of Igneous Asteroids in the Inner and Middle Main Belt

    CERN Document Server

    Hammergren, Mark; Gyuk, Geza; Puckett, Andrew

    2012-01-01

    We present the spectra of 60 asteroids, including 47 V-types observed during the first phase of the Adler V-Type Asteroid (AVAST) Survey. SDSS photometry was used to select candidate V-type asteroids for follow up by nature of their very blue i - z color. 47 of the 61 observed candidates were positively classified as V-type asteroids, while an additional six show indications of a 0.9 {\\mu}m feature consistent with V-type spectra, but not sufficient for formal classification. Four asteroids were found to be S-type, all of which had i - z values very near the adopted AVAST selection criteria of i - z \\leq -0.2, including one candidate observed well outside the cut (at a mean i - z of -0.11). Three A-type asteroids were also identified. Six V-type asteroids were identified beyond the 3:1 mean motion resonance with Jupiter, and six more were found with low (< 5 deg) inclination, placing these asteroids outside of the normal dynamical range of classic Vestoids, and are suggestive of a non-Vesta origin for at le...

  8. Asteroid science by Gaia

    Science.gov (United States)

    Muinonen, Karri; Cellino, Alberto; Dell Oro, Aldo; Tanga, Paolo; Delbo, Marco; Mignard, Francois; Thuillot, William; Berthier, Jerome; Carry, Benoit; Hestroffer, Daniel; Granvik, Mikael; Fedorets, Grigori

    2016-07-01

    Since the start of its regular observing program in summer 2014, the Gaia mission has carried out systematic photometric, spectrometric, and astrometric observations of asteroids. In total, the unique capabilities of Gaia allow for the collection of an extensive and homogeneous data set of some 350,000 asteroids down to the limiting magnitude of G = 20.7 mag. The Gaia performance remains excellent over the entire available brightness range. Starting from 2003, a working group of European asteroid scientists has explored the main capabilities of the mission, defining the expected scientific impact on Solar System science. These results have served as a basis for developing the Gaia data reduction pipeline, within the framework of the Data Processing and Analysis Consortium (DPAC). We describe the distribution of the existing and forecoming Gaia observations in space and time for different categories of objects. We illustrate the peculiar properties of each single observation, as these properties will affect the subsequent exploitation of the mission data. We will review the expected performances of Gaia, basically as a function of magnitude and proper motion of the sources. We will further focus on the areas that will benefit from complementary observational campaigns to improve the scientific return of the mission, and on the involvement of the planetary science community as a whole in the exploitation of the Gaia survey. We will thus describe the current and future opportunities for ground-based observers and forthcoming changes brought by Gaia in some observational approaches, such as stellar occultations by transneptunian objects and asteroids. We will show first results from the daily, short-term processing of Gaia data, all the way from the onboard data acquisition to the ground-based processing. We illustrate the tools developed to compute predictions of asteroid observations, we discuss the procedures implemented by the daily processing, and we illustrate

  9. AsteroidZoo: A New Zooniverse project to detect asteroids and improve asteroid detection algorithms

    Science.gov (United States)

    Beasley, M.; Lewicki, C. A.; Smith, A.; Lintott, C.; Christensen, E.

    2013-12-01

    We present a new citizen science project: AsteroidZoo. A collaboration between Planetary Resources, Inc., the Zooniverse Team, and the Catalina Sky Survey, we will bring the science of asteroid identification to the citizen scientist. Volunteer astronomers have proved to be a critical asset in identification and characterization of asteroids, especially potentially hazardous objects. These contributions, to date, have required that the volunteer possess a moderate telescope and the ability and willingness to be responsive to observing requests. Our new project will use data collected by the Catalina Sky Survey (CSS), currently the most productive asteroid survey, to be used by anyone with sufficient interest and an internet connection. As previous work by the Zooniverse has demonstrated, the capability of the citizen scientist is superb at classification of objects. Even the best automated searches require human intervention to identify new objects. These searches are optimized to reduce false positive rates and to prevent a single operator from being overloaded with requests. With access to the large number of people in Zooniverse, we will be able to avoid that problem and instead work to produce a complete detection list. Each frame from CSS will be searched in detail, generating a large number of new detections. We will be able to evaluate the completeness of the CSS data set and potentially provide improvements to the automated pipeline. The data corpus produced by AsteroidZoo will be used as a training environment for machine learning challenges in the future. Our goals include a more complete asteroid detection algorithm and a minimum computation program that skims the cream of the data suitable for implemention on small spacecraft. Our goal is to have the site become live in the Fall 2013.

  10. Asteroid lightcurves from the Palomar Transient Factory survey: Rotation periods and phase functions from sparse photometry

    CERN Document Server

    Waszczak, Adam; Ofek, Eran O; Laher, Russ; Masci, Frank; Levitan, David; Surace, Jason; Cheng, Yu-Chi; Ip, Wing-Huen; Kinoshita, Daisuke; Helou, George; Prince, Thomas A; Kulkarni, Shrinivas

    2015-01-01

    We fit 54,296 sparsely-sampled asteroid lightcurves in the Palomar Transient Factory to a combined rotation plus phase-function model. Each lightcurve consists of 20+ observations acquired in a single opposition. Using 805 asteroids in our sample that have reference periods in the literature, we find the reliability of our fitted periods is a complicated function of the period, amplitude, apparent magnitude and other attributes. Using the 805-asteroid ground-truth sample, we train an automated classifier to estimate (along with manual inspection) the validity of the remaining 53,000 fitted periods. By this method we find 9,033 of our lightcurves (of 8,300 unique asteroids) have reliable periods. Subsequent consideration of asteroids with multiple lightcurve fits indicate 4% contamination in these reliable periods. For 3,902 lightcurves with sufficient phase-angle coverage and either a reliably-fit period or low amplitude, we examine the distribution of several phase-function parameters, none of which are bimo...

  11. Asteroid mining

    Science.gov (United States)

    Gertsch, Richard E.

    1992-01-01

    The earliest studies of asteroid mining proposed retrieving a main belt asteroid. Because of the very long travel times to the main asteroid belt, attention has shifted to the asteroids whose orbits bring them fairly close to the Earth. In these schemes, the asteroids would be bagged and then processed during the return trip, with the asteroid itself providing the reaction mass to propel the mission homeward. A mission to one of these near-Earth asteroids would be shorter, involve less weight, and require a somewhat lower change in velocity. Since these asteroids apparently contain a wide range of potentially useful materials, our study group considered only them. The topics covered include asteroid materials and properties, asteroid mission selection, manned versus automated missions, mining in zero gravity, and a conceptual mining method.

  12. A Spectroscopic And Photometric Survey Of Selected Near-earth Asteroids: Results From 2008-2012.

    Science.gov (United States)

    Hicks, Michael D.; Lawrence, K. J.; Somers, J.; Teague, S.; Strojia, C.; Dombroski, D.; Davtyan, T.; Barajas, T.; Truong, T.; McCormack, M.; Gerhart, C.; Garcia, K.; Rhoades, H.; Mayes, D.; Shitanishi, J.; Foster, J.; McAuley, A.

    2012-10-01

    Over the past four years we have used the dual-channel optical spectrometer (DBSP) at the Palomar 200-inch telescope (P200) to collect low-resolution spectroscopy of Near-Earth Asteroids (NEAs) and have been awarded, on average, three nights per semester. Additionally, we have ample access to the JPL Table Mountain 0.6-m (TMO) telescope for time-resolved Bessel BVRI photometry. Undergraduate students from the CURE program (Consortium for Undergraduate Research Experience) have provided a large fraction of the observing effort at TMO. With these two telescopes, we strove to characterize all bright (VEarth asteroids (as potential mission targets). In this paper we will present our observational results for 150 NEAs. Our data products are diverse, and can include taxonomic classification, broad-band colors, rotational period, solar phase behavior and absolute magnitude, and 3-d shape/pole models derived from lightcurve inversion. We will discuss the variability between main-belt and near-Earth spectral families, quantify differences between PHA and background near-Earth populations, and present our first attempts to generate a spectral photometry using solely near-Earth asteroids. This research was funded by NASA. The student participation was supported by the National Science Foundation under REU grant 0852088 to Cal State LA.

  13. BAOBAB (Big And Outrageously Bold Asteroid Belt) Project

    Science.gov (United States)

    Mcfadden, L. A.; Thomas, C. A; Englander, J. A.; Ruesch, O.; Hosseini, S.; Goossens, S. J.; Mazarico, E. M.; Schmerr, N.

    2017-01-01

    One of the intriguing results of NASA's Dawn mission is the composition and structure of the Main Asteroid Belt's only known dwarf planet, Ceres [1]. It has a top layer of dehydrated clays and salts [2] and an icy-rocky mantle [3,4]. It is widely known that the asteroid belt failed to accrete as a planet by resonances between the Sun and Jupiter. About 20-30 asteroids >100 km diameter are probably differentiated protoplanets [5]. 1) how many more and which ones are fragments of protoplanets? 2) How many and which ones are primordial rubble piles left over from condensation of the solar nebula? 3) How would we go about gaining better and more complete characterization of the mass, interior structure and composition of the Main Belt asteroid population? 4) What is the relationship between asteroids and ocean worlds? Bulk parameters such as the mass, density, and porosity, are important to characterize the structure of any celestial body, and for asteroids in particular, they can shed light on the conditions in the early solar system. Asteroid density estimates exist but currently they are often based on assumed properties of taxonomic classes, or through astronomical survey data where interactions with asteroids are weak at best resulting in large measurement uncertainty. We only have direct density estimates from spacecraft encounters for a few asteroids at this time. Knowledge of the asteroids is significant not only to understand their role in solar system workings, but also to assess their potential as space resources, as impact hazards on Earth, or even as harboring life forms. And for the distant future, we want to know if the idea put forth in a contest sponsored by Physics Today, to surface the asteroids into highly reflecting, polished surfaces and use them as a massively segmented mirror for astrophysical exploration [6], is feasible.

  14. Human Missions to Near-Earth Asteroids: An Update on NASA's Current Status and Proposed Activities for Small Body Exploration

    Science.gov (United States)

    Abell, P. A.; Mazanek, D. D.; Barbee, B. W.; Mink, R. G.; Landis, R. R.; Adamo, D. R.; Johnson, L. N.; Yeomans, D. K.; Reeves, D. M.; Larman, K. T.; Drake, B. G.; Friedensen, V. P.

    2012-01-01

    Over the past several years, much attention has been focused on the human exploration of near-Earth asteroids (NEAs). Two independent NASA studies examined the feasibility of sending piloted missions to NEAs, and in 2009, the Augustine Commission identified NEAs as high profile destinations for human exploration missions beyond the Earth-Moon system as part of the Flexible Path. More recently the current U.S. presidential administration directed NASA to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010.

  15. Applied Astronomy: Asteroid Prospecting

    Science.gov (United States)

    Elvis, M.

    2013-09-01

    In the age of asteroid mining the ability to find promising ore-bearing bodies will be valuable. This will give rise to a new discipline- "Applied Astronomy". Just as most geologists work in industry, not in academia, the same will be true of astronomers. Just how rare or common ore-rich asteroids are likely to be, and the skills needed to assay their value, are discussed here, with an emphasis on remote - telescopic - methods. Also considered are the resources needed to conduct extensive surveys of asteroids for prospecting purposes, and the cost and timescale involved. The longer-term need for applied astronomers is also covered.

  16. [Current situation of health surveys in Spain].

    Science.gov (United States)

    Requena, María Luisa; Suárez, Mónica; Pérez, Óscar

    2013-01-01

    To describe the evolution of health interview surveys in Spain (as of 01/01/2012), whether national or regional, its main characteristics and methodology, and in the case of general health surveys (GHIS), its contents. An adapted version of Eurostat quality control template European Health Interview Survey Technical and Methodological Report was filled in by those responsible for GHIS in each region (autonomous communities) and at the national level. The first part (11 questions) gathers general information about health surveys, both GHIS and surveys targeted to specific populations or health problems (SHIS). The second part (109 questions) asks about methodological characteristics of most recent GHIS. 1) regional or supra-regional scope; 2) for the second part, GHIS currently active series. Quality control was performed using double data entry and validated by informants.100 HIS were identified. 16 were GHIS and 84 SHIS. 32 (38%) of the latter were national and 52 (62%) regional. Nutrition 21 (25%), drug use 10 (12%), opinion polls 7 (9%) and dental health 7 (9%) were the most frequent topics in SHIS. Highest GHIS density was reached after year 2000, with several surveys on field at a time (mode=3). 11 GHIS (2 national, 9 regional) met inclusion criteria for the second part. All complied with general quality benchmarks. Few differences were observed in content.GHIS show more similarities than differences in objectives, methods and content. Rationalization and harmonization are needed. Physical activity, alcohol consumption, quality of life and mental health instruments are not yet consensual. Valid and comparable data are required on health status and its determinants to inform health policy.

  17. Asteroid Redirect

    OpenAIRE

    De Aquino, Fran

    2017-01-01

    Asteroids are a great threat to mankind. Here we will show that it is possible to redirect them from their trajectories by means of a strong gravitational repulsion, produced by the gravitational interaction between the asteroid and a Gravitational Spacecraft positioned close to the asteroid.

  18. NASA's Asteroid Redirect Mission (ARM)

    Science.gov (United States)

    Abell, P. A.; Mazanek, D. D.; Reeves, D. M.; Chodas, P. W.; Gates, M. M.; Johnson, L. N.; Ticker, R. L.

    2017-01-01

    Mission Description and Objectives: NASA's Asteroid Redirect Mission (ARM) consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), a robotic mission to visit a large (greater than approximately 100 meters diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will explore and investigate the boulder and return to Earth with samples. The ARRM is currently planned to launch at the end of 2021 and the ARCM is scheduled for late 2026.

  19. Near-Sun asteroids

    Science.gov (United States)

    Emel'yanenko, V. V.

    2017-01-01

    As follows from dynamical studies, in the course of evolution, most near-Earth objects reach orbits with small perihelion distances. Changes of the asteroids in the vicinity of the Sun should play a key role in forming the physical properties, size distribution, and dynamical features of the near-Earth objects. Only seven of the discovered asteroids are currently moving along orbits with perihelion distances q orbits farther from the Sun. In this study, we found asteroids that have been recently orbiting with perihelion distances q orbits for hundreds to tens of thousands of years. To carry out astrophysical observations of such objects is a high priority.

  20. Asteroid detection using a single multi-wavelength CCD scan

    Science.gov (United States)

    Melton, Jonathan

    2016-09-01

    Asteroid detection is a topic of great interest due to the possibility of diverting possibly dangerous asteroids or mining potentially lucrative ones. Currently, asteroid detection is generally performed by taking multiple images of the same patch of sky separated by 10-15 minutes, then subtracting the images to find movement. However, this is time consuming because of the need to revisit the same area multiple times per night. This paper describes an algorithm that can detect asteroids using a single CCD camera scan, thus cutting down on the time and cost of an asteroid survey. The algorithm is based on the fact that some telescopes scan the sky at multiple wavelengths with a small time separation between the wavelength components. As a result, an object moving with sufficient speed will appear in different places in different wavelength components of the same image. Using image processing techniques we detect the centroids of points of light in the first component and compare these positions to the centroids in the other components using a nearest neighbor algorithm. The algorithm was used on a test set of 49 images obtained from the Sloan telescope in New Mexico and found 100% of known asteroids with only 3 false positives. This algorithm has the advantage of decreasing the amount of time required to perform an asteroid scan, thus allowing more sky to be scanned in the same amount of time or freeing a telescope for other pursuits.

  1. Asteroid Photometry

    CERN Document Server

    Li, Jian-Yang; Buratti, Bonnie J; Takir, Driss; Clark, Beth Ellen

    2015-01-01

    Asteroid photometry has three major applications: providing clues about asteroid surface physical properties and compositions, facilitating photometric corrections, and helping design and plan ground-based and spacecraft observations. The most significant advances in asteroid photometry in the past decade were driven by spacecraft observations that collected spatially resolved imaging and spectroscopy data. In the mean time, laboratory measurements and theoretical developments are revealing controversies regarding the physical interpretations of models and model parameter values. We will review the new developments in asteroid photometry that have occurred over the past decade in the three complementary areas of observations, laboratory work, and theory. Finally we will summarize and discuss the implications of recent findings.

  2. Multiple origins of asteroid pairs

    CERN Document Server

    Jacobson, Seth A

    2015-01-01

    Rotationally fissioned asteroids produce unbound daughter asteroids that have very similar heliocentric orbits. Backward integration of their current heliocentric orbits provides an age of closest proximity that can be used to date the rotational fission event. Most asteroid pairs follow a predicted theoretical relationship between the primary spin period and the mass ratio of the two pair members that is a direct consequence of the YORP-induced rotational fission hypothesis. If the progenitor asteroid has strength, asteroid pairs may have high mass ratios with possibly fast rotating primaries. However, secondary fission leaves the originally predicted trend unaltered. We also describe the characteristics of pair members produced by four alternative routes from a rotational fission event to an asteroid pair. Unlike direct formation from the event itself, the age of closest proximity of these pairs cannot generally be used to date the rotational fission event since considerable time may have passed.

  3. Asteroid taxonomy

    Science.gov (United States)

    Tholen, David J.; Barucci, M. Antonietta

    1989-01-01

    The spectral reflectivity of asteroid surfaces over the wavelength range of 0.3 to 1.1 micron can be used to classify these objects into several broad groups with similar spectral characteristics. The three most recently developed taxonomies group the asteroids into 9, 11, or 14 different clases, depending on the technique used to perform the analysis. The distribution of the taxonomic classes shows that darker and redder objects become more dominant at larger heliocentric distances, while the rare asteroid types are found more frequently among the small objects of the planet-crossing population.

  4. Spectral Classification of Asteroids by Random Forest

    Science.gov (United States)

    Huang, C.; Ma, Y. H.; Zhao, H. B.; Lu, X. P.

    2016-09-01

    With the increasing asteroid spectral and photometric data, a variety of classification methods for asteroids have been proposed. This paper classifies asteroids based on the observations of Sloan Digital Sky Survey (SDSS) Moving Object Catalogue (MOC) by using the random forest algorithm. With the training data derived from the taxonomies of Tholen, Bus, Lazzaro, DeMeo, and Principal Component Analysis, we classify 48642 asteroids according to g, r, i, and z SDSS magnitudes. In this way, asteroids are divided into 8 spectral classes (C, X, S, B, D, K, L, and V).

  5. A search for differentiated fragments within asteroid families

    Science.gov (United States)

    DeMeo, Francesca E.; Carry, Benoit; Polishook, David; Binzel, Richard; Burt, Brian; Moskovitz, Nicholas

    2016-10-01

    The existence of iron meteorite samples suggest that a number of planetesimals differentiated fully and were subsequently disrupted. Within the current asteroid belt, there is little evidence of bodies that fully differentiated into core, mantle and crust layers (Moskovitz et al. 2008). However, because it has been suggested that differentiation can occur within the interior of a body while the primitive exterior remains intact (Elkins-Tanton et al. 2011), an understanding of the diversity of compositions from differentiated parent bodies is critical. Asteroid families, as constituents of a disrupted progenitor body, provide a glimpse into the interior of their progenitors. However, asteroid families, while spectrally unique from one another, are spectrally similar within each family (Parker et al., 2008, Masiero et al. 2011). Using the Sloan Digital Sky Survey (SDSS) to search for a "needle in a haystack" we identify candidate basaltic and olivine-rich asteroids that are dynamically associated with asteroid families to constrain the amount of differentiation that could have occurred within the parent asteroid. Using FIRE on the 6-meter Magellan Telescope and SpeX on the 3-meter IRTF Telescope we measure near-infrared spectra of more than thirty of these candidates, most of which are part of the Eunomia and Flora families. Results of these observations are presented in this talk.

  6. Low Delta-V Near-Earth Asteroids: a survey of suitable targets for space missions

    CERN Document Server

    Ieva, S; Perna, D; Barucci, M A; Bernardi, F; Fornasier, S; De Luise, F; Perozzi, E; Rossi, A; Brucato, J R

    2014-01-01

    In the last decades Near-Earth Objects (NEOs) have become very important targets to study, since they can give us clues to the formation, evolution and composition of the Solar System. In addition, they may represent either a threat to humankind, or a repository of extraterrestrial resources for suitable space-borne missions. Within this framework, the choice of next-generation mission targets and the characterisation of a potential threat to our planet deserve special attention. To date, only a small part of the 11,000 discovered NEOs have been physically characterised. From ground and space-based observations one can determine some basic physical properties of these objects using visible and infrared spectroscopy. We present data for 13 objects observed with different telescopes around the world (NASA-IRTF, ESO-NTT, TNG) in the 0.4 - 2.5 um spectral range, within the NEOSURFACE survey (http://www.oa-roma.inaf.it/planet/NEOSurface.html). Objects are chosen from among the more accessible for a rendez-vous mis...

  7. The Asteroid Impact Mission

    Science.gov (United States)

    Carnelli, Ian; Galvez, Andres; Mellab, Karim

    2016-04-01

    The Asteroid Impact Mission (AIM) is a small and innovative mission of opportunity, currently under study at ESA, intending to demonstrate new technologies for future deep-space missions while addressing planetary defense objectives and performing for the first time detailed investigations of a binary asteroid system. It leverages on a unique opportunity provided by asteroid 65803 Didymos, set for an Earth close-encounter in October 2022, to achieve a fast mission return in only two years after launch in October/November 2020. AIM is also ESA's contribution to an international cooperation between ESA and NASA called Asteroid Impact Deflection Assessment (AIDA), consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the AIM rendezvous spacecraft. The primary goals of AIDA are to test our ability to perform a spacecraft impact on a near-Earth asteroid and to measure and characterize the deflection caused by the impact. The two mission components of AIDA, DART and AIM, are each independently valuable but when combined they provide a greatly increased scientific return. The DART hypervelocity impact on the secondary asteroid will alter the binary orbit period, which will also be measured by means of lightcurves observations from Earth-based telescopes. AIM instead will perform before and after detailed characterization shedding light on the dependence of the momentum transfer on the asteroid's bulk density, porosity, surface and internal properties. AIM will gather data describing the fragmentation and restructuring processes as well as the ejection of material, and relate them to parameters that can only be available from ground-based observations. Collisional events are of great importance in the formation and evolution of planetary systems, own Solar System and planetary rings. The AIDA scenario will provide a unique opportunity to observe a collision event directly in space, and simultaneously from ground-based optical and

  8. New study reveals twice as many asteroids as previously believed

    Science.gov (United States)

    2002-05-01

    The ISO satellite Credits: ESA ISO An artist's impression of the ISO spacecraft. The ISO Deep Asteroid Search indicates that there are between 1.1 million and 1.9 million 'space rocks' larger than 1 kilometre in diameter in the so-called 'main asteroid belt', about twice as many as previously believed. However, astronomers think it is premature to revise current assessments of the risk of the Earth being hit by an asteroid. Despite being in our own Solar System, asteroids can be more difficult to study than very distant galaxies. With sizes of up to one thousand kilometres in diameter, the brightness of these rocky objects may vary considerably in just a few minutes. They move very quickly with respect to the stars - they have been dubbed 'vermin of the sky' because they often appear as trails on long exposure images. This elusiveness explains why their actual number and size distribution remains uncertain. Most of the almost 40,000 asteroids catalogued so far (1) orbit the Sun forming the 'main asteroid belt', between Mars and Jupiter, too far to pose any threat to Earth. However, space-watchers do keep a closer eye on another category of asteroids, the 'Near Earth Asteroids' or 'NEAs', which are those whose orbits cross, or are likely to cross, that of our planet. The ISO Deep Asteroid Search (IDAS), the first systematic search for these objects performed in infrared light, focused on main belt asteroids. Because it is impossible to simply point the telescope at the whole main belt and count, astronomers choose selected regions of the belt and then use a theoretical model to extrapolate the data to the whole belt. Edward Tedesco (TerraSystems, Inc., New Hampshire, United States) and François-Xavier Desert (Observatoire de Grenoble, France) observed their main belt selected areas in 1996 and 1997 with ESA's ISO. They found that in the middle region of the belt the density of asteroids was 160 asteroids larger than 1 kilometre per square degree - an area of the

  9. Asteroid structure

    Science.gov (United States)

    Asphaug, E.

    2014-07-01

    Even before the first space missions to asteroids, in the mid-1990s, it was known that asteroids have weird structures. Photometry indicated complicated shapes, and the pioneering radar investigations by Ostro and colleagues followed by adaptive optics campaigns and flybys showed odd binary forms, and confirmed the common presence of satellites, and indications of highly varying surface roughness. Some asteroids turned out to be dominated by a single major cratering event, while others showed no evidence of a major crater, or perhaps for global crater erasure. The first space mission to orbit an asteroid, NEAR, found a mixture of heavily cratered terrains and geomorphically active 'ponds', and indicated evidence for global seismicity from impact. The next mission to orbit an asteroid, Hayabusa, found what most agree is a rubble pile, with no major craters and an absence of fines. There is to date no direct evidence of asteroid interior geology, other than measurements of bulk density, and inferences made for mass distribution asymmetry based on dynamics, and inferences based on surface lineaments. Interpolating from the surface to the interior is always risky and usually wrong, but of course the answer is important since we are someday destined to require this knowledge in order to divert a hazardous asteroid from impact with the Earth. Even considering the near-subsurface, here we remain as ignorant as we were about the Moon in the early 1960s, whether the surface will swallow us up in dust, or will provide secure landing and anchoring points. Laboratory experimentation in close to zero-G is still in its early stages. Adventures such as mining and colonization will surely have to wait until we better know these things. How do we get from here to there? I will focus on 3 areas of progress: (1) asteroid cratering seismology, where we use the surface craters to understand what is going on inside; (2) numerical modeling of collisions, which predicts the internal

  10. Superresolution imaging: a survey of current techniques

    Science.gov (United States)

    Cristóbal, G.; Gil, E.; Šroubek, F.; Flusser, J.; Miravet, C.; Rodríguez, F. B.

    2008-08-01

    Imaging plays a key role in many diverse areas of application, such as astronomy, remote sensing, microscopy, and tomography. Owing to imperfections of measuring devices (e.g., optical degradations, limited size of sensors) and instability of the observed scene (e.g., object motion, media turbulence), acquired images can be indistinct, noisy, and may exhibit insuffcient spatial and temporal resolution. In particular, several external effects blur images. Techniques for recovering the original image include blind deconvolution (to remove blur) and superresolution (SR). The stability of these methods depends on having more than one image of the same frame. Differences between images are necessary to provide new information, but they can be almost unperceivable. State-of-the-art SR techniques achieve remarkable results in resolution enhancement by estimating the subpixel shifts between images, but they lack any apparatus for calculating the blurs. In this paper, after introducing a review of current SR techniques we describe two recently developed SR methods by the authors. First, we introduce a variational method that minimizes a regularized energy function with respect to the high resolution image and blurs. In this way we establish a unifying way to simultaneously estimate the blurs and the high resolution image. By estimating blurs we automatically estimate shifts with subpixel accuracy, which is inherent for good SR performance. Second, an innovative learning-based algorithm using a neural architecture for SR is described. Comparative experiments on real data illustrate the robustness and utilization of both methods.

  11. Discovery and dynamical characterization of the Amor-class asteroid 2012 XH16

    Science.gov (United States)

    Wlodarczyk, I.; Cernis, K.; Boyle, R. P.; Laugalys, V.

    2014-03-01

    The near-Earth asteroid belt is continuously replenished with material originally moving in Amor-class orbits. Here, the orbit of the dynamically interesting Amor-class asteroid 2012 XH16 is analysed. This asteroid was discovered with the Vatican Advanced Technology Telescope (VATT) at the Mt Graham International Observatory as part of an ongoing asteroid survey focused on astrometry and photometry. The orbit of the asteroid was computed using 66 observations (57 obtained with VATT and 9 from the Lunar and Planetary Laboratory-Spacewatch II project) to give a = 1.63 au, e = 0.36, i = 3.76°. The absolute magnitude of the asteroid is 22.3 which translates into a diameter in the range 104-231 m, assuming the average albedos of S-type and C-type asteroids, respectively. We have used the current orbit to study the future dynamical evolution of the asteroid under the perturbations of the planets and the Moon, relativistic effects, and the Yarkovsky force. Asteroid 2012 XH16 is locked close to the strong 1:2 mean motion resonance with the Earth. The object shows stable evolution and could survive in near-resonance for a relatively long period of time despite experiencing frequent close encounters with Mars. Moreover, results of our computations show that the asteroid 2012 XH16 can survive in the Amor region at most for about 200-400 Myr. The evolution is highly chaotic with a characteristic Lyapunov time of 245 yr. Jupiter is the main perturber but the effects of Saturn, Mars and the Earth-Moon system are also important. In particular, secular resonances with Saturn are significant.

  12. Simultaneous Mass Determination for Gravitationally Coupled Asteroids

    Science.gov (United States)

    Baer, James; Chesley, Steven R.

    2017-08-01

    The conventional least-squares asteroid mass determination algorithm allows us to solve for the mass of a large subject asteroid that is perturbing the trajectory of a smaller test asteroid. However, this algorithm is necessarily a first approximation, ignoring the possibility that the subject asteroid may itself be perturbed by the test asteroid, or that the encounter’s precise geometry may be entangled with encounters involving other asteroids. After reviewing the conventional algorithm, we use it to calculate the masses of 30 main-belt asteroids. Compared to our previous results, we find new mass estimates for eight asteroids (11 Parthenope, 27 Euterpe, 51 Neimausa, 76 Freia, 121 Hermione, 324 Bamberga, 476 Hedwig, and 532 Herculina) and significantly more precise estimates for six others (2 Pallas, 3 Juno, 4 Vesta, 9 Metis, 16 Psyche, and 88 Thisbe). However, we also find that the conventional algorithm yields questionable results in several gravitationally coupled cases. To address such cases, we describe a new algorithm that allows the epoch state vectors of the subject asteroids to be included as solve-for parameters, allowing for the simultaneous solution of the masses and epoch state vectors of multiple subject and test asteroids. We then apply this algorithm to the same 30 main-belt asteroids and conclude that mass determinations resulting from current and future high-precision astrometric sources (such as Gaia) should conduct a thorough search for possible gravitational couplings and account for their effects.

  13. Small asteroid system evolution

    OpenAIRE

    Jacobson, Seth A.

    2014-01-01

    Observations with radar, photometric and direct imaging techniques have discovered that multiple asteroid systems can be divided clearly into a handful of different morphologies, and recently, the discovery of small unbound asteroid systems called asteroid pairs have revolutionized the study of small asteroid systems. Simultaneously, new theoretical advances have demonstrated that solar radiation dictates the evolution of small asteroids with strong implications for asteroid internal structur...

  14. Small asteroid system evolution

    OpenAIRE

    Jacobson, Seth A.

    2014-01-01

    Observations with radar, photometric and direct imaging techniques have discovered that multiple asteroid systems can be divided clearly into a handful of different morphologies, and recently, the discovery of small unbound asteroid systems called asteroid pairs have revolutionized the study of small asteroid systems. Simultaneously, new theoretical advances have demonstrated that solar radiation dictates the evolution of small asteroids with strong implications for asteroid internal structur...

  15. Search for Asteroid-Asteroid Encounters

    Directory of Open Access Journals (Sweden)

    Luis A. Mammana

    2001-01-01

    Full Text Available Earlier studies about asteroids did not consider mutual interactions since they assume a negligible asteroid mass. In 1966 Hertz took into account for the first time the gravitational effects produced by an asteroid on another for mass determination. This gravitational action becomes relevant for enough effective encounters. The most efficient gravitational interaction is that produced in a large time interval and for small distances. For each particular caseful it is relevant to perform a care analysis in order to determinate the feasibility in the mass determination and improved orbital elements. In the present paper we performed a search of asteroid-asteroid encounters occurred in the twenty century for the first 3000 numbered asteroids . Of all encounters we have selected only those asteroid pairs in which one of the asteroids has a diameter larger than 200 km and the other one (the smaller an observational interval of at least ten years.

  16. Asteroids. Prospective energy and material resources

    Energy Technology Data Exchange (ETDEWEB)

    Badescu, Viorel (ed.) [Bucharest Polytechnic Univ. (Romania). Candida Oancea Institute

    2013-11-01

    Recent research on Prospective Energy and Material Resources on Asteroids. Carefully edited book dedicated to Asteroids prospective energy and material resources. Written by leading experts in the field. The Earth has limited material and energy resources while these resources in space are virtually unlimited. Further development of humanity will require going beyond our planet and exploring of extraterrestrial resources and sources of unlimited power. Thus far, all missions to asteroids have been motivated by scientific exploration. However, given recent advancements in various space technologies, mining asteroids for resources is becoming ever more feasible. A significant portion of asteroids value is derived from their location; the required resources do not need to be lifted at a great expense from the surface of the Earth. Resources derived from Asteroid not only can be brought back to Earth but could also be used to sustain human exploration of space and permanent settlements in space. This book investigates asteroids' prospective energy and material resources. It is a collection of topics related to asteroid exploration, and utilization. It presents past and future technologies and solutions to old problems that could become reality in our life time. The book therefore is a great source of condensed information for specialists involved in current and impending asteroid-related activities and a good starting point for space researchers, inventors, technologists and potential investors. Written for researchers, engineers, and businessmen interested in asteroids' exploration and exploitation.

  17. MOS: A critical tool for current and future radio surveys

    CERN Document Server

    Smith, Daniel J B

    2015-01-01

    Since radio continuum observations are not affected by dust obscuration, they are of immense potential diagnostic power as cosmological probes and for studying galaxy formation and evolution out to high redshifts. However, the power-law nature of radio frequency spectra ensures that ancillary spectroscopic information remains critical for studying the properties of the faint radio sources being detected in rapidly-increasing numbers on the pathway to the Square Kilometre Array. In this contribution, I present some of the key scientific motivations for exploiting the immense synergies between radio continuum observations and multi-object spectroscopic surveys. I review some of the ongoing efforts to obtain the spectra necessary to harness the huge numbers of star-forming galaxies and AGN that current and future radio surveys will detect. I also touch on the WEAVE-LOFAR survey, which will use the WEAVE spectrograph currently being built for the William Herschel Telescope to target hundreds of thousands of low f...

  18. Surveying the Commons: Current Implementation of Information Commons Web sites

    Science.gov (United States)

    Leeder, Christopher

    2009-01-01

    This study assessed the content of 72 academic library Information Commons (IC) Web sites using content analysis, quantitative assessment and qualitative surveys of site administrators to analyze current implementation by the academic library community. Results show that IC Web sites vary widely in content, design and functionality, with few…

  19. A Search for Asteroids, Moons, and Rings Orbiting White Dwarfs

    CERN Document Server

    Di Stefano, Rosanne; Kawaler, Steven D

    2009-01-01

    Do white dwarfs host asteroid systems? Although several lines of argument suggest that white dwarfs may be orbited by large populations of asteroids, transits would provide the most direct evidence. We demonstrate that the Kepler mission has the capability to detect transits of white dwarfs by asteroids. Because white-dwarf asteroid systems, if they exist, are likely to contain many asteroids orbiting in a spatially extended distribution, discoveries of asteroid transits can be made by monitoring only a small number of white dwarfs, compatible with Kepler's primary mission, which is to monitor stars with potentially habitable planets. Possible future missions that survey ten times as many stars with similar sensitivity and minute-cadence monitoring can establish the characteristics of asteroid systems around white dwarfs, such as the distribution of asteroid sizes and semimajor axes. Transits by planets would be more dramatic, but the probability that they will occur is lower. Ensembles of planetary moons and...

  20. Anatomy of an Asteroid Breakup

    Science.gov (United States)

    Kohler, Susanna

    2017-05-01

    rather than gradual).Timeline of the destruction of R3. Calendar dates are in black, day-of-year dates are in red. The letters below the timeline indicate observations. [Jewitt et al. 2017]So if it wasnt an impact, what caused the breakup of R3? Tidal stresses are unlikely; the asteroid wasnt close enough to the Sun or a planet to experience strong pulls. Gas pressure from sublimating ice also falls short of being strong enough to have caused the disruption, according to the authors calculations.The authors conclude that the most plausible cause of R3s breakup was rotational instability. If an asteroid is made up of a collection of rocky material loosely gravitationally bound in whats known as a rubble-pile composition, then it tends to fly apart if the asteroid spins faster than once every 2.2 hours. The authors show that torques from radiation or anisotropic sublimation could have driven R3 to spin this quickly on a relatively short timescale.A Dusty EndZodiacal light, caused by scattering by dust in the Zodiacal Cloud. [ESO]Lastly, Jewitt and collaborators examine the debris cloud released by the breakup of R3. They use these observations to estimate how much debris disrupted asteroids likely contribute to the Zodiacal Cloud, the cloud of dust found in our solar system, primarily between the Sun and Jupiter.The authors estimate that the fractional contribution by asteroids like R3 is roughly 4% consistent with models that suggest that asteroid dust is a measurable, but not dominant, contributor to the Zodiacal Cloud. Future sky surveys will allow us to better examine this contribution.CitationDavid Jewitt et al 2017 AJ 153 223. doi:10.3847/1538-3881/aa6a57

  1. Active Near Earth Asteroids

    Science.gov (United States)

    Jenniskens, Peter

    2015-08-01

    Past activity from Near Earth Asteroids is recorded in the meteoroid streams that cause our meteor showers. Automated meteoroid orbit surveys by photographic, low-light video, specular radar, and head-echo radar reflections are providing the first maps of meteor shower activity at different particle sizes. There are distinct differences in particle size distributions among streams. The underlaying mechanisms that created these streams are illuminated: fragmentation from spin-up or thermal stresses, meteoroid ejection by water vapor drag, and ejection of icy particles by CO and CO2 sublimation. The distribution of the meteoroid orbital elements probe the subsequent evolution by planetary perturbations and sample the range of dynamical processes to which Near Earth Asteroids are exposed. The non-stream "sporadic" meteors probe early stages in the evolution from meteoroid streams into the zodiacal dust cloud. We see that the lifetime of large meteoroids is generally not limited by collisions. Results obtained by the CAMS video survey of meteoroid orbits are compared to those from other orbit surveys. Since October 2010, over 200,000 meteoroid orbits have been measured. First results from an expansion into the southern hemisphere are also presented, as are first results from the measurement of main element compositions. Among the many streams detected so far, the Geminid and Sextantid showers stand out by having a relatively high particle density and derive from parent bodies that appear to have originated in the main belt.

  2. The Rafita asteroid family

    Science.gov (United States)

    Aljbaae, S.; Carruba, V.; Masiero, J. R.; Domingos, R. C.; Huaman, M.

    2017-01-01

    The Rafita asteroid family is an S-type group located in the middle main belt, on the right side of the 3J:-1A mean-motion resonance. The proximity of this resonance to the family left side in semi-major axis caused many former family members to be lost. As a consequence, the family shape in the (a, 1/D) domain is quite asymmetrical, with a preponderance of objects on the right side of the distribution. The Rafita family is also characterized by a leptokurtic distribution in inclination, which allows the use of methods of family age estimation recently introduced for other leptokurtic families such as Astrid, Hansa, Gallia, and Barcelona. In this work we propose a new method based on the behavior of an asymmetry coefficient function of the distribution in the (a, 1/D) plane to date incomplete asteroid families such as Rafita. By monitoring the time behavior of this coefficient for asteroids simulating the initial conditions at the time of the family formation, we were able to estimate that the Rafita family should have an age of 490 ± 200 Myr, in good agreement with results from independent methods such as Monte Carlo simulations of Yarkovsky and Yorp dynamical induced evolution and the time behaviour of the kurtosis of the sin (i) distribution. Asteroids from the Rafita family can reach orbits similar to 8% of the currently known near Earth objects. ≃1% of the simulated objects are present in NEO-space during the final 10 Myr of the simulation, and thus would be comparable to objects in the present-day NEO population.

  3. Colors of Dynamically Associated Asteroid Pairs

    CERN Document Server

    Moskovitz, Nicholas

    2012-01-01

    Recent dynamical studies have identified pairs of asteroids that reside in nearly identical heliocentric orbits. Possible formation scenarios for these systems include dissociation of binary asteroids, collisional disruption of a single parent body, or spin-up and rotational fission of a rubble-pile. Aside from detailed dynamical analyses and measurement of rotational light curves, little work has been done to investigate the colors or spectra of these unusual objects. A photometric and spectroscopic survey was conducted to determine the reflectance properties of asteroid pairs. New observations were obtained for a total of 34 individual asteroids. Additional photometric measurements were retrieved from the Sloan Digital Sky Survey Moving Object Catalog. Colors or spectra for a total of 42 pair components are presented here. The main findings of this work are: (1) the components in the observed pair systems have the same colors within the uncertainties of this survey, and (2) the color distribution of asteroi...

  4. A Survey of Current e-Business (E-Government

    Directory of Open Access Journals (Sweden)

    Don Vance Kerr

    2008-05-01

    Full Text Available The Internet is a dynamic part of the business scene and there have been many examples of success and failures of e-commerce and e-business ventures. A survey was administered asking questions about industries understanding of current e-business (e-government practices in Australia. The object of the survey was to provide a benchmark of current practice. The results of this survey could have a major impact on academic curricula. The survey was sent to 671 Australian Businesses and was addressed to the Chief Information Officer. Only twenty four usable questionnaires were returned and while it is accepted that this is a limited sample, disturbing trends have appeared with respect to the lack of strategic planning for information technology use particularly in medium sized businesses in Australia. In addition, relationships between key factors associated with the business objectives for their IT infrastructure and the benefits of the organisation’s Extranet, Intranet and Internet initiatives were identified.

  5. Utility survey of requirements for a HTS fault current limiter

    DEFF Research Database (Denmark)

    Nielsen, Jan Nygaard; Jørgensen, P.; Østergaard, Jacob;

    2000-01-01

    The application of superconducting fault current limiters (SFCL) in the electric utility sector will clearly dependent on to what extent the needs and requirements of electric utilities can be met by the ongoing development of SFCL technology. This paper considers a questionnaire survey of which ...... needs and expectations the Danish electric utilities have to this new technology. A bus-tie application of SFCL in a distribution substation with three parallel-coupled transformers is discussed......The application of superconducting fault current limiters (SFCL) in the electric utility sector will clearly dependent on to what extent the needs and requirements of electric utilities can be met by the ongoing development of SFCL technology. This paper considers a questionnaire survey of which...

  6. Comet or Asteroid?

    Science.gov (United States)

    1997-11-01

    When is a minor object in the solar system a comet? And when is it an asteroid? Until recently, there was little doubt. Any object that was found to display a tail or appeared diffuse was a comet of ice and dust grains, and any that didn't, was an asteroid of solid rock. Moreover, comets normally move in rather elongated orbits, while most asteroids follow near-circular orbits close to the main plane of the solar system in which the major planets move. However, astronomers have recently discovered some `intermediate' objects which seem to possess properties that are typical for both categories. For instance, a strange object (P/1996 N2 - Elst-Pizarro) was found last year at ESO ( ESO Press Photo 36/96 ) which showed a cometary tail, while moving in a typical asteroidal orbit. At about the same time, American scientists found another (1996 PW) that moved in a very elongated comet-type orbit but was completely devoid of a tail. Now, a group of European scientists, by means of observations carried out at the ESO La Silla observatory, have found yet another object that at first appeared to be one more comet/asteroid example. However, continued and more detailed observations aimed at revealing its true nature have shown that it is most probably a comet . Consequently, it has received the provisional cometary designation P/1997 T3 . The Uppsala-DLR Trojan Survey Some time ago, Claes-Ingvar Lagerkvist (Astronomical Observatory, Uppsala, Sweden), in collaboration with Gerhard Hahn, Stefano Mottola, Magnus Lundström and Uri Carsenty (DLR, Institute of Planetary Exploration, Berlin, Germany), started to study the distribution of asteroids near Jupiter. They were particularly interested in those that move in orbits similar to that of Jupiter and which are located `ahead' of Jupiter in the so-called `Jovian L4 Lagrangian point'. Together with those `behind' Jupiter, these asteroids have been given the names of Greek and Trojan Heroes who participated in the famous Trojan war

  7. On the Astrid asteroid family

    CERN Document Server

    Carruba, V

    2016-01-01

    Among asteroid families, the Astrid family is peculiar because of its unusual inclination distribution. Objects at $a\\simeq$~2.764 au are quite dispersed in this orbital element, giving the family a "crab-like" appearance. Recent works showed that this feature is caused by the interaction of the family with the $s-s_C$ nodal secular resonance with Ceres, that spreads the inclination of asteroids near its separatrix. As a consequence, the currently observed distribution of the $v_W$ component of terminal ejection velocities obtained from inverting Gauss equation is quite leptokurtic, since this parameter mostly depends on the asteroids inclination. The peculiar orbital configuration of the Astrid family can be used to set constraints on key parameters describing the strength of the Yarkovsky force, such as the bulk and surface density and the thermal conductivity of surface material. By simulating various fictitious families with different values of these parameters, and by demanding that the current value of ...

  8. Survey of Induced Voltage and Current Phenomena in GIS Substation

    Directory of Open Access Journals (Sweden)

    Seyed Mohammad Hassan Hosseini

    2014-03-01

    Full Text Available Induced capacitive voltage and current in high voltage GIS substation is one of the most significant phenomena that may have made some problems in this substation operation. At this study the various equipment of 420 KV Karoon4 substations such as powerhouses, input and output lines, bus-bar and bus-duct have simulated by applying EMTP-RV software. Then with the different condition of single-phase and three-phase faults on the lines in critical conditions, capacitive induction voltage and current by parallel capacitor with circuit breaker is surveyed. The results show the value of this induced current and voltage and that this critical conditions the breakers and dis-connector switches must be able to interrupt this value of current.

  9. Bimodal Programming: A Survey of Current Clinical Practice.

    Science.gov (United States)

    Siburt, Hannah W; Holmes, Alice E

    2015-06-01

    The purpose of this study was to determine the current clinical practice in approaches to bimodal programming in the United States. To be specific, if clinicians are recommending bimodal stimulation, who programs the hearing aid in the bimodal condition, and what method is used for programming the hearing aid? An 11-question online survey was created and sent via email to a comprehensive list of cochlear implant programming centers in the United States. The survey was sent to 360 recipients. Respondents in this study represented a diverse group of clinical settings (response rate: 26%). Results indicate little agreement about who programs the hearing aids, when they are programmed, and how they are programmed in the bimodal condition. Analysis of small versus large implant centers indicated small centers are less likely to add a device to the contralateral ear. Although a growing number of cochlear implant recipients choose to wear a hearing aid on the contralateral ear, there is inconsistency in the current clinical approach to bimodal programming. These survey results provide evidence of large variability in the current bimodal programming practices and indicate a need for more structured clinical recommendations and programming approaches.

  10. The Catalina Sky Survey: Current and Future Work

    Science.gov (United States)

    Christensen, Eric; Larson, S.; Boattini, A.; Gibbs, A.; Grauer, A.; Hill, R.; Johnson, J.; Kowalski, R.; McNaught, R.

    2012-10-01

    The Catalina Sky Survey (CSS) continues to be the most productive Near Earth Object (NEO) survey in operation, accounting for nearly two-thirds of all NEO discoveries since 2005. We present a review of the current status of the survey operations, and highlight recent and future upgrades to our instrumentation. Recently, CSS has refurbished a 1.0-m telescope on Mt. Lemmon, Arizona, adjacent to the 1.5-m survey telescope. This telescope will be primarily used for NEO follow-up, recovery, and physical characterization of NEOs including colors and light curves. It will be capable of remote or robotic operations, programmed by adaptive queue-planning software of our own design. We expect to complete commissioning activities and begin full-time operations by the end of this year. A large-format camera featuring a single 10k x 10k detector is in the process of being fabricated for the 1.5-m survey telescope. The new camera system will increase the field-of-view from 1.2 to 5.0 square degrees, and the nightly coverage rate from 180 to 750 square degrees, to limiting magnitude V 21.5. This telescope is already the most productive for NEO discovery, accounting for approximately 40% of new NEOs since 2008, at an average rate of over 350 NEOs per year. We anticipate a significant increase in its discovery rate after commissioning, which will begin in late 2013. The Catalina Sky Survey gratefully acknowledges the support of NASA’s Near Earth Object Observation program (grant no. NNH12ZDA001N-NEOO).

  11. Voyage to Troy: A mission concept for the exploration of the Trojan asteroids

    Science.gov (United States)

    Saikia, S.; Das, A.; Laipert, F.; Dapkus, C.; Kendall, J.; Bowling, T.; Steckloff, J.; Holbert, S.; Graves, K.; Anthony, T.; Bobick, R.; Huang, Y.; Stuart, J.; Longuski, J.; Minton, D.

    2014-07-01

    The Trojan asteroids, located at Jupiter's L4 and L5 Lagrange points, are a potential source of insights into long-standing questions on the origin and early history of the Solar System. The 2013 Planetary Science Decadal Survey recommends a Trojan Tour and Rendezvous mission as high-priority among medium-class missions. A dedicated mission to the Trojan asteroids could confirm or refute multiple theories to correctly explain the Trojan asteroids' current location, characteristics, and behavior. In-depth and conclusive evidence for the Trojan asteroids' internal and external make-up as well as dynamical behavior hav been challenging due to limitations of ground- and space-based observations. Notwithstanding these limitations, it has been inferred that there are two distinct sub- populations that are distinguishable in visible and near-infrared spectra (redder and less red) within the swarms. These spectral groupings have not yet been conclusively linked to physical characteristics (e.g. size) or other observed parameters (e.g. albedo) of the primordial bodies. NASA's Jet Propulsion Laboratory's concept studies for Decadal Survey evaluated three concepts for missions to Trojan asteroids: each utilizing chemical- solar-electric, and radioisotope-electric for propulsion. Both Solar and Advanced Stirling Radioisotope Generators were considered for power [2]. We present a new conceptual mission to explore the Trojan asteroids that achieves the science goals prioritized in the 2013 Planetary Science Decadal Survey. The proposed mission aims to study both a redder and less red asteroid for the surface mineralogical and elemental composition, state of surface regolith, evidence and consequences of external modification processes such as collisional evolution, space weathering, and irradiation. Some potential targets in the L4 Greek camp currently under consideration for this mission include Achilles, Hektor and Agamemnon (redder) and Eurybates, Deipylos and Kalchas (less

  12. Surveying rip current survivors: preliminary insights into the experiences of being caught in rip currents

    Science.gov (United States)

    Drozdzewski, D.; Shaw, W.; Dominey-Howes, D.; Brander, R.; Walton, T.; Gero, A.; Sherker, S.; Goff, J.; Edwick, B.

    2012-04-01

    This paper begins a process of addressing a significant gap in knowledge about people's responses to being caught in rip currents. While rip currents are the primary hazard facing recreational ocean swimmers in Australia, debate exists about the best advice to give swimmers caught in rip currents. Such surf rescue advice - on what to do and how to respond when caught in a rip - relies on empirical evidence. However, at present, knowledge about swimmers reactions and responses to rip currents is limited. This gap is a considerable barrier to providing effective advice to beach goers and to understanding how this advice is utilised (or not) when actually caught in the rip current. This paper reports the findings of a pilot study that focussed on garnering a better understanding of swimmers' experiences when caught in rip currents. A large scale questionnaire survey instrument generated data about rip current survivors' demographics, knowledge of beach safety and their reactions and responses when caught in a rip current. A mix of online and paper surveys produced a total of 671 completed surveys. Respondents were predominantly an informed group in terms of rip current knowledge, beach experience and had a high self-rated swimming ability. Preliminary insights from the survey show that most respondents recalled a "swim across the rip/parallel to the beach" message when caught in the rip and most escaped unassisted by acting on this message. However, while nearly a quarter of respondents recalled a message of "not to panic", short answer responses revealed that the onset of panic inhibited some respondents from recalling or enacting any other type of beach safety message when caught in the rip current. Results also showed that despite the research sample being younger, competent and frequent ocean swimmers, they were more likely to swim at unpatrolled beaches and outside of the red and yellow safety flags. Moreover, they were still caught in a rip current and they

  13. Surveying rip current survivors: preliminary insights into the experiences of being caught in rip currents

    Directory of Open Access Journals (Sweden)

    D. Drozdzewski

    2012-04-01

    Full Text Available This paper begins a process of addressing a significant gap in knowledge about people's responses to being caught in rip currents. While rip currents are the primary hazard facing recreational ocean swimmers in Australia, debate exists about the best advice to give swimmers caught in rip currents. Such surf rescue advice – on what to do and how to respond when caught in a rip – relies on empirical evidence. However, at present, knowledge about swimmers reactions and responses to rip currents is limited. This gap is a considerable barrier to providing effective advice to beach goers and to understanding how this advice is utilised (or not when actually caught in the rip current.

    This paper reports the findings of a pilot study that focussed on garnering a better understanding of swimmers' experiences when caught in rip currents. A large scale questionnaire survey instrument generated data about rip current survivors' demographics, knowledge of beach safety and their reactions and responses when caught in a rip current. A mix of online and paper surveys produced a total of 671 completed surveys. Respondents were predominantly an informed group in terms of rip current knowledge, beach experience and had a high self-rated swimming ability. Preliminary insights from the survey show that most respondents recalled a "swim across the rip/parallel to the beach" message when caught in the rip and most escaped unassisted by acting on this message. However, while nearly a quarter of respondents recalled a message of "not to panic", short answer responses revealed that the onset of panic inhibited some respondents from recalling or enacting any other type of beach safety message when caught in the rip current. Results also showed that despite the research sample being younger, competent and frequent ocean swimmers, they were more likely to swim at unpatrolled beaches and outside of the red and yellow safety flags. Moreover, they were still

  14. Current Trends in Nursing Informatics: Results of an International Survey.

    Science.gov (United States)

    Peltonen, Laura-Maria; Alhuwail, Dari; Ali, Samira; Badger, Martha K; Eler, Gabrielle Jacklin; Georgsson, Mattias; Islam, Tasneem; Jeon, Eunjoo; Jung, Hyunggu; Kuo, Chiu-Hsiang; Lewis, Adrienne; Pruinelli, Lisiane; Ronquillo, Charlene; Sarmiento, Raymond Francis; Sommer, Janine; Tayaben, Jude L; Topaz, Maxim

    2016-01-01

    Nursing informatics (NI) can help provide effective and safe healthcare. This study aimed to describe current research trends in NI. In the summer 2015, the IMIA-NI Students Working Group created and distributed an online international survey of the current NI trends. A total of 402 responses were submitted from 44 countries. We identified a top five NI research areas: standardized terminologies, mobile health, clinical decision support, patient safety and big data research. NI research funding was considered to be difficult to acquire by the respondents. Overall, current NI research on education, clinical practice, administration and theory is still scarce, with theory being the least common. Further research is needed to explain the impact of these trends and the needs from clinical practice.

  15. Asteroid Mining and Prospecting

    OpenAIRE

    Esty, Thomas

    2013-01-01

    There has been a recent increase in interest in the idea of mining asteroids, as seen from the founding of multiple companies who seek to make this science fiction idea science fact. We analyzed a number of prior papers on asteroids to make an estimate as to whether mining asteroids is within the realm of possibility. Existing information on asteroid number, composition, and orbit from past research was synthesized with a new analysis using binomial statistics of the number of probes that wou...

  16. Wake Survey of a Marine Current Turbine Under Steady Conditions

    Science.gov (United States)

    Lust, Ethan; Luznik, Luksa; Flack, Karen

    2016-11-01

    A submersible particle image velocimetry (PIV) system was used to study the wake of a horizontal axis marine current turbine. The turbine was tested in a large tow tank facility at the United States Naval Academy. The turbine is a 1/25th scale model of the U.S. National Renewable Energy Laboratory's Reference Model 1 (RM1) tidal turbine. It is a two-bladed turbine measuring 0.8 m in diameter and featuring a NACA 63-618 airfoil cross section. Separate wind tunnel testing has shown the foil section used on the turbine to be Reynolds number independent with respect to lift at the experimental parameters of tow carriage speed (Utow = 1 . 68 m/s) and tip speed ratio (TSR = 7). The wake survey was conducted over an area extending 0.25D forward of the turbine tip path to 2.0D aft, and to a depth of 1.0D beneath the turbine output shaft in the streamwise plane. Each field of view was approximately 30 cm by 30 cm, and each overlapped the adjacent fields of view by 5 cm. The entire flow field was then reconstructed into a single field of investigation. Results include streamwise and vertical ensemble average velocity fields averaged over approximately 1,000 realizations, as well as higher-order statistics. Turbine tip vortex centers were identified and plotted showing increasing aperiodicity with wake age. keywords: horizontal axis marine current turbine, particle image velocimetry, towing tank, wake survey

  17. Survey of biomass gasification. Volume III. Current technology and research

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-04-01

    This survey of biomass gasification was written to aid the Department of Energy and the Solar Energy Research Institute Biological and Chemical Conversion Branch in determining the areas of gasification that are ready for commercialization now and those areas in which further research and development will be most productive. Chapter 8 is a survey of gasifier types. Chapter 9 consists of a directory of current manufacturers of gasifiers and gasifier development programs. Chapter 10 is a sampling of current gasification R and D programs and their unique features. Chapter 11 compares air gasification for the conversion of existing gas/oil boiler systems to biomass feedstocks with the price of installing new biomass combustion equipment. Chapter 12 treats gas conditioning as a necessary adjunct to all but close-coupled gasifiers, in which the product is promptly burned. Chapter 13 evaluates, technically and economically, synthesis-gas processes for conversion to methanol, ammonia, gasoline, or methane. Chapter 14 compiles a number of comments that have been assembled from various members of the gasifier community as to possible roles of the government in accelerating the development of gasifier technology and commercialization. Chapter 15 includes recommendations for future gasification research and development.

  18. Rotational Study of Ambiguous Taxonomic Classified Asteroids

    Science.gov (United States)

    Linder, Tyler R.; Sanchez, Rick; Wuerker, Wolfgang; Clayson, Timothy; Giles, Tucker

    2017-01-01

    The Sloan Digital Sky Survey (SDSS) moving object catalog (MOC4) provided the largest ever catalog of asteroid spectrophotometry observations. Carvano et al. (2010), while analyzing MOC4, discovered that individual observations of asteroids which were observed multiple times did not classify into the same photometric-based taxonomic class. A small subset of those asteroids were classified as having both the presence and absence of a 1um silicate absorption feature. If these variations are linked to differences in surface mineralogy, the prevailing assumption that an asteroid’s surface composition is predominantly homogenous would need to be reexamined. Furthermore, our understanding of the evolution of the asteroid belt, as well as the linkage between certain asteroids and meteorite types may need to be modified.This research is an investigation to determine the rotational rates of these taxonomically ambiguous asteroids. Initial questions to be answered:Do these asteroids have unique or nonstandard rotational rates?Is there any evidence in their light curve to suggest an abnormality?Observations were taken using PROMPT6 a 0.41-m telescope apart of the SKYNET network at Cerro Tololo Inter-American Observatory (CTIO). Observations were calibrated and analyzed using Canopus software. Initial results will be presented at AAS.

  19. Asteroid thermophysical modeling

    CERN Document Server

    Delbo, Marco; Emery, Joshua P; Rozitis, Ben; Capria, Maria Teresa

    2015-01-01

    The field of asteroid thermophysical modeling has experienced an extraordinary growth in the last ten years, as new thermal infrared data became available for hundreds of thousands of asteroids. The infrared emission of asteroids depends on the body's size, shape, albedo, thermal inertia, roughness and rotational properties. These parameters can therefore be derived by thermophysical modeling of infrared data. Thermophysical modeling led to asteroid size estimates that were confirmed at the few-percent level by later spacecraft visits. We discuss how instrumentation advances now allow mid-infrared interferometric observations as well as high-accuracy spectro-photometry, posing their own set of thermal-modeling challenges.We present major breakthroughs achieved in studies of the thermal inertia, a sensitive indicator for the nature of asteroids soils, allowing us, for instance, to determine the grain size of asteroidal regoliths. Thermal inertia also governs non-gravitational effects on asteroid orbits, requir...

  20. Towards an Airframe Noise Prediction Methodology: Survey of Current Approaches

    Science.gov (United States)

    Farassat, Fereidoun; Casper, Jay H.

    2006-01-01

    In this paper, we present a critical survey of the current airframe noise (AFN) prediction methodologies. Four methodologies are recognized. These are the fully analytic method, CFD combined with the acoustic analogy, the semi-empirical method and fully numerical method. It is argued that for the immediate need of the aircraft industry, the semi-empirical method based on recent high quality acoustic database is the best available method. The method based on CFD and the Ffowcs William- Hawkings (FW-H) equation with penetrable data surface (FW-Hpds ) has advanced considerably and much experience has been gained in its use. However, more research is needed in the near future particularly in the area of turbulence simulation. The fully numerical method will take longer to reach maturity. Based on the current trends, it is predicted that this method will eventually develop into the method of choice. Both the turbulence simulation and propagation methods need to develop more for this method to become useful. Nonetheless, the authors propose that the method based on a combination of numerical and analytical techniques, e.g., CFD combined with FW-H equation, should also be worked on. In this effort, the current symbolic algebra software will allow more analytical approaches to be incorporated into AFN prediction methods.

  1. Asteroids Were Born Big

    CERN Document Server

    Morbidelli, Alessandro; Nesvorny, David; Levison, Harold F

    2009-01-01

    How big were the first planetesimals? We attempt to answer this question by conducting coagulation simulations in which the planetesimals grow by mutual collisions and form larger bodies and planetary embryos. The size frequency distribution (SFD) of the initial planetesimals is considered a free parameter in these simulations, and we search for the one that produces at the end objects with a SFD that is consistent with asteroid belt constraints. We find that, if the initial planetesimals were small (e.g. km-sized), the final SFD fails to fulfill these constraints. In particular, reproducing the bump observed at diameter D~100km in the current SFD of the asteroids requires that the minimal size of the initial planetesimals was also ~100km. This supports the idea that planetesimals formed big, namely that the size of solids in the proto-planetary disk ``jumped'' from sub-meter scale to multi-kilometer scale, without passing through intermediate values. Moreover, we find evidence that the initial planetesimals ...

  2. A Survey of Current Rotorcraft Propulsion Health Monitoring Technologies

    Science.gov (United States)

    Delgado, Irebert R.; Dempsey, Paula J.; Simon, Donald L.

    2012-01-01

    A brief review is presented on the state-of-the-art in rotorcraft engine health monitoring technologies including summaries on current practices in the area of sensors, data acquisition, monitoring and analysis. Also, presented are guidelines for verification and validation of Health Usage Monitoring System (HUMS) and specifically for maintenance credits to extend part life. Finally, a number of new efforts in HUMS are summarized as well as lessons learned and future challenges. In particular, gaps are identified to supporting maintenance credits to extend rotorcraft engine part life. A number of data sources were consulted and include results from a survey from the HUMS community, Society of Automotive Engineers (SAE) documents, American Helicopter Society (AHS) papers, as well as references from Defence Science & Technology Organization (DSTO), Civil Aviation Authority (CAA), and Federal Aviation Administration (FAA).

  3. Asteroid spin-up fission systems

    Science.gov (United States)

    Pravec, P.

    2014-07-01

    Among asteroids smaller than about 15 km in diameter, there is a population of binary and multiple asteroid systems that show characteristics strongly suggesting their formation by spin-up fission. I will review the current observational data we have on the systems and compare them with predictions from theories of formation of asteroid systems. I will show that the best explanation of their observed properties is provided by the theory of fission of cohesionless (rubble-pile) asteroids spun up to the critical spin frequency by the YORP effect. Observed asteroid systems are of two kinds: bound and unbound. Bound asteroid systems typically consist of a larger primary and one or two smaller satellites. Unbound systems consist of two asteroids orbiting the Sun on highly similar orbits, again with one being typically larger (primary) and the other being smaller (secondary). These two groups are not exclusive; there exist systems with one or two bound and an unbound secondary. Our current sample consists of 133 bound asteroid systems (binaries or triples) with primary sizes between 0.12 and 13 km and of 178 asteroid pairs with similar primary sizes. Bound systems have been observed in heliocentric orbits from near the Earth to the outer main belt, while asteroid pairs are recognizable only in the main belt where their orbits are only slowly dispersed so the pairs can be identified for up to 2 Myr after formation. The leading observational techniques for discovery and characterization of asteroid systems are radar imagery (for near-Earth asteroid systems) and lightcurve photometry (for main-belt ones). The observed characteristics of asteroid systems suggesting their formation by rotational fission of parent rubble-pile asteroids after being spun up by the YORP effect are as follows. The angular momentum content of binary asteroids is close to critical. The orientations of satellite orbits are non-random; the orbital poles concentrate near the obliquities of 0 and 180

  4. Origins for the near-earth asteroids

    Science.gov (United States)

    Binzel, Richard P.; Xu, Shui; Bus, Schelte J.; Bowell, Edward

    1992-01-01

    Because of their short dynamical lifetimes, the population of near-earth asteroids (NEAs) must be resupplied. Two sources have been hypothesized: main-belt asteroids and extinct comet nuclei. A new survey of physical properties for less than 5 kilometers diameter main-belt asteroids reveals that their spin rate and shape distributions are similar to those of NEAs, as is fully consistent with a main-belt origin for most NEAs. Physical data on comet nuclei are limited. If the existing sample is representative of the comet population, analysis of the asteroid and comet samples constrains the fraction of comet nuclei to between 0 and 40 percent of the total NEA population.

  5. The empty primordial asteroid belt.

    Science.gov (United States)

    Raymond, Sean N; Izidoro, Andre

    2017-09-01

    The asteroid belt contains less than a thousandth of Earth's mass and is radially segregated, with S-types dominating the inner belt and C-types the outer belt. It is generally assumed that the belt formed with far more mass and was later strongly depleted. We show that the present-day asteroid belt is consistent with having formed empty, without any planetesimals between Mars and Jupiter's present-day orbits. This is consistent with models in which drifting dust is concentrated into an isolated annulus of terrestrial planetesimals. Gravitational scattering during terrestrial planet formation causes radial spreading, transporting planetesimals from inside 1 to 1.5 astronomical units out to the belt. Several times the total current mass in S-types is implanted, with a preference for the inner main belt. C-types are implanted from the outside, as the giant planets' gas accretion destabilizes nearby planetesimals and injects a fraction into the asteroid belt, preferentially in the outer main belt. These implantation mechanisms are simple by-products of terrestrial and giant planet formation. The asteroid belt may thus represent a repository for planetary leftovers that accreted across the solar system but not in the belt itself.

  6. Survey of currently selected dental implants and restorations by prosthodontists.

    Science.gov (United States)

    Cardoso, Richard C; Gerngross, Peter J; Dominici, John T; Kiat-amnuay, Sudarat

    2013-01-01

    The purpose of this study was to survey the prosthodontists of the American College of Prosthodontists (ACP) and the American Academy of Maxillofacial Prosthetics (AAMP) to identify the most commonly used implant both during their training and currently in practice, and to evaluate overall restorative preference. Participants were asked to rank criteria that make an implant company desirable and important features when selecting an implant. An electronic survey was emailed to 1,739 members of the ACP and AAMP. The majority of respondents (79%) were trained using Nobel Biocare brand implants, which was also the brand most often selected by participants for use in all regions of the oral cavity (34% to 39%, location dependent). Abutment preferences varied by area: incisors and canines (29%) and highly esthetic areas (53%) were more likely to be restored with custom milled zirconia abutments, while prefabricated titanium abutments were preferred for premolars and molar areas. Conventional loading was most often applied, ranging from 95% in medically compromised patients to 55% in esthetic areas. The majority of participants (86%) used Locator attachments for complete overdenture restorations. Also, respondents selected an implant company based on features and literature support versus cost and customer service. The implant features deemed most important were the design of the internal connection and ease of finding replacement parts; thread design and variety of abutments were deemed least important. Respondents reported that while implant planning software was used, they rarely/never order the concurrent surgical guide. Within the study's limitations, the majority of prosthodontists select implants based on training, features, and literature support.

  7. Asteroid exploration and utilization

    Science.gov (United States)

    Radovich, Brian M.; Carlson, Alan E.; Date, Medha D.; Duarte, Manny G.; Erian, Neil F.; Gafka, George K.; Kappler, Peter H.; Patano, Scott J.; Perez, Martin; Ponce, Edgar

    1992-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources possessed by asteroids have enormous potential for aiding and enhancing human space exploration as well as life on Earth. Project STONER (Systematic Transfer of Near Earth Resources) is based on mining an asteroid and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plan for humans to utilize asteroid resources. Project STONER is divided into two parts: asteroid selection and explorer spacecraft design. The spacecraft design team is responsible for the selection and integration of the subsystems: GNC, communications, automation, propulsion, power, structures, thermal systems, scientific instruments, and mechanisms used on the surface to retrieve and store asteroid regolith. The sample return mission scenario consists of eight primary phases that are critical to the mission.

  8. Bibliometric Analysis of Current Web Survey Research in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qian; SHAO Peiji; FANG Jiaming

    2008-01-01

    In recent years, with the advancement of information technology and its application in survey activities, web surveys have not only greatly developed, but have also encountered many problems in China. An analysis of domestic research is important for better understanding of web surveys, to guide further research and application. This paper gives a bibliometric analysis of 120 domestic articles on web surveys from 1998 to 2006, on publication growth, author and organization distribution, journal distribution, and research subjects. Research on web surveys in China should make progress comparable with research abroad in comparative studies, specific studies, and technical application studies.

  9. Current State of Agile User-Centered Design: A Survey

    Science.gov (United States)

    Hussain, Zahid; Slany, Wolfgang; Holzinger, Andreas

    Agile software development methods are quite popular nowadays and are being adopted at an increasing rate in the industry every year. However, these methods are still lacking usability awareness in their development lifecycle, and the integration of usability/User-Centered Design (UCD) into agile methods is not adequately addressed. This paper presents the preliminary results of a recently conducted online survey regarding the current state of the integration of agile methods and usability/UCD. A world wide response of 92 practitioners was received. The results show that the majority of practitioners perceive that the integration of agile methods with usability/UCD has added value to their adopted processes and to their teams; has resulted in the improvement of usability and quality of the product developed; and has increased the satisfaction of the end-users of the product developed. The top most used HCI techniques are low-fidelity prototyping, conceptual designs, observational studies of users, usability expert evaluations, field studies, personas, rapid iterative testing, and laboratory usability testing.

  10. Modeling Asteroid Dynamics using AMUSE: First Test Cases

    NARCIS (Netherlands)

    Frantseva, Kateryna; Mueller, Michael; van der Tak, Floris; Helmich, Frank P.

    2015-01-01

    We are creating a dynamic model of the current asteroid population. The goal is to reproduce measured impact rates in the current Solar System, from which we'll derive delivery rates of water and organic material by tracing low-albedo C-class asteroids (using the measured albedo distribution from WI

  11. Modeling Asteroid Dynamics using AMUSE: First Test Cases

    NARCIS (Netherlands)

    Frantseva, Kateryna; Mueller, Michael; van der Tak, Floris; Helmich, Frank P.

    2015-01-01

    We are creating a dynamic model of the current asteroid population. The goal is to reproduce measured impact rates in the current Solar System, from which we'll derive delivery rates of water and organic material by tracing low-albedo C-class asteroids (using the measured albedo distribution from

  12. Modeling Asteroid Dynamics using AMUSE: First Test Cases

    NARCIS (Netherlands)

    Frantseva, Kateryna; Mueller, Michael; van der Tak, Floris; Helmich, Frank P.

    2015-01-01

    We are creating a dynamic model of the current asteroid population. The goal is to reproduce measured impact rates in the current Solar System, from which we'll derive delivery rates of water and organic material by tracing low-albedo C-class asteroids (using the measured albedo distribution from WI

  13. Mineralogy and Surface Composition of Asteroids

    CERN Document Server

    Reddy, Vishnu; Thomas, Cristina A; Moskovitz, Nicholas A; Burbine, Thomas H

    2015-01-01

    Methods to constrain the surface mineralogy of asteroids have seen considerable development during the last decade with advancement in laboratory spectral calibrations and validation of our interpretive methodologies by spacecraft rendezvous missions. This has enabled the accurate identification of several meteorite parent bodies in the main asteroid belt and helped constrain the mineral chemistries and abundances in ordinary chondrites and basaltic achondrites. With better quantification of spectral effects due to temperature, phase angle, and grain size, systematic discrepancies due to non-compositional factors can now be virtually eliminated for mafic silicate-bearing asteroids. Interpretation of spectrally featureless asteroids remains a challenge. This paper presents a review of all mineralogical interpretive tools currently in use and outlines procedures for their application.

  14. The Cratering History of Asteroid (21) Lutetia

    CERN Document Server

    Marchi, S; Vincent, J -B; Morbidelli, A; Mottola, S; Marzari, F; Kueppers, M; Besse, S; Thomas, N; Barbieri, C; Naletto, G; Sierks, H

    2011-01-01

    The European Space Agency's Rosetta spacecraft passed by the main belt asteroid (21) Lutetia the 10th July 2010. With its ~100km size, Lutetia is one of the largest asteroids ever imaged by a spacecraft. During the flyby, the on-board OSIRIS imaging system acquired spectacular images of Lutetia's northern hemisphere revealing a complex surface scarred by numerous impact craters, reaching the maximum dimension of about 55km. In this paper, we assess the cratering history of the asteroid. For this purpose, we apply current models describing the formation and evolution of main belt asteroids, that provide the rate and velocity distributions of impactors. These models, coupled with appropriate crater scaling laws, allow us to interpret the observed crater size-frequency distribution (SFD) and constrain the cratering history. Thanks to this approach, we derive the crater retention age of several regions on Lutetia, namely the time lapsed since their formation or global surface reset. We also investigate the influe...

  15. Design of MGA trajectories for main belt asteroid

    Institute of Scientific and Technical Information of China (English)

    崔祜涛; 乔栋; 崔平远; 栾恩杰

    2003-01-01

    Asteroid exploration is one of the most sophisticated missions currently being investigated. Gravityassist trajectories have proven valuable in interplanetary missions such as the Pioneer, Voyager and Galileo. In this paper, we design interplanetary trajectory for main belt asteroid exploration mission with the Mars gravityassist (MGA) using "pork chop" plots and patched-conic theory and give some initial valuable trajectory parameters on main belt asteroid exploration mission with MGA.

  16. Two new basaltic asteroids in the Outer Main Belt

    CERN Document Server

    Duffard, R

    2007-01-01

    The identification of other basaltic objects in the asteroid belt is mandatory to explain the diversity in the collection of basaltic meteorites. This diversity requires more than one differentiated parent body, a fact that is consistent with the diversity of differentiated parent bodies implied by the iron meteorites. Based on a list of previously identified candidate basaltic (V-type) asteroids, two asteroids in the outer main belt, (7472) Kumakiri and (10537) 1991 RY16, were spectroscopically observed during an observational run in Calar Alto Observatory, Spain. We confirm the V-type character of these two asteroids that, together with (1459) Magnya, become the only known traces of basaltic found in the outer main belt up to now. We also demonstrate that the searching for candidate V-type asteroids using a photometric survey, like the Sloan Digital Sky Survey, produces reliable results.

  17. Asteroid families, dynamics and astrometry

    Science.gov (United States)

    Williams, J. G.; Gibson, J.

    1987-01-01

    The proper elements and family assignments for the 1227 Palomar-Leiden Survey asteroids of high quality were tabulated. In addition to the large table, there are also auxiliary tables of Mars crossers and commensurate objects, histograms of the proper element distributions, and a discussion. Probably the most important part of the discussion describes the Mars crossing boundary, how the closest distances of approach to Mars and Jupiter are calculated, and why the observed population of Mars crossers should bombard that planet episodically rather than uniformly. Analytical work was done to derive velocity distributions of family forming events from proper element distributions subject to assumptions which may be appropriate for cratering events. Software was developed for a microcomputer to permit plotting of the proper elements. Three orthogonal views are generated and stereo pairs can be printed when desired. This program was created for the study of asteroid families. The astrometry task is directed toward measuring and reducing positions on faint comets and the minor planets with less common orbits. The observational material is CCD frames taken with the Palomar 1.5 m telescope. Positions of 10 comets and 16 different asteroids were published on the Minor Planet Circulars.

  18. Near Earth Asteroid (NEA) Scout

    Science.gov (United States)

    Johnson, Les; Castillo-Rogez, Julie; Dervan, Jared; McNutt, Leslie

    2017-01-01

    NASA is developing solar sail propulsion for a near-term Near Earth Asteroid (NEA) reconnaissance mission that will lay the groundwork for the future use of solar sails. The NEA Scout mission will use the sail as primary propulsion allowing it to survey and image one NEA's of interest for future human exploration. NEA Scout will launch on the first mission of the Space Launch System (SLS) in 2018. After its first encounter with the Moon, NEA Scout will enter the sail characterization phase by the 86 square meter sail deployment. A mechanical Active Mass Translation (AMT) system, combined with the remaining ACS propellant, will be used for sail momentum management. The spacecraft will perform a series of lunar flybys to achieve optimum departure trajectory before beginning its two year-long cruise. About one month before the asteroid flyby, NEA Scout will start its approach phase using optical navigation on top of radio tracking. The solar sail will provide NEA Scout continuous low thrust to enable a relatively slow flyby of the target asteroid under lighting conditions favorable to geological imaging. Once complete, NASA will have demonstrated the capability to fly low-cost, high delta V CubeSats to perform interplanetary missions.

  19. Surveying clinicians by web: current issues in design and administration.

    Science.gov (United States)

    Dykema, Jennifer; Jones, Nathan R; Piché, Tara; Stevenson, John

    2013-09-01

    The versatility, speed, and reduced costs with which web surveys can be conducted with clinicians are often offset by low response rates. Drawing on best practices and general recommendations in the literature, we provide an evidence-based overview of methods for conducting online surveys with providers. We highlight important advantages and disadvantages of conducting provider surveys online and include a review of differences in response rates between web and mail surveys of clinicians. When administered online, design-based features affect rates of survey participation and data quality. We examine features likely to have an impact including sample frames, incentives, contacts (type, timing, and content), mixed-mode approaches, and questionnaire length. We make several recommendations regarding optimal web-based designs, but more empirical research is needed, particularly with regard to identifying which combinations of incentive and contact approaches yield the highest response rates and are the most cost-effective.

  20. The Asteroid Redirect Mission (ARM)

    Science.gov (United States)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Mazanek, Dan; Reeves, David; Ticker, Ronald

    2016-07-01

    be made approximately a year before launch, but there is a strong recommendation from the scientific and resource utilization communities that the ARM target be volatile and organic rich. Three of the proposed candidates are carbonaceous NEAs. Specifically, the ARRM reference target, 2008 EV5 is a carbonaceous (C-type) asteroid that has been remotely characterized (via visual, infrared, and radar wavelengths), is believed to be hydrated, and provides significant return mass (boulders on the surface greater than 20 metric tons). It also has an advantage in that the orbital dynamics of the NEA fall within the current baseline mission timeline of five years between the return of the robotic vehicle to cis-lunar space and the launch of the ARCM. Therefore, NEA 2008 EV5 provides a valid target that can be used to help with formulation and development efforts. Input to ARM and Future Activities: In the fall of 2015, NASA chartered the Formulation Assessment and Support Team (FAST) to provide timely inputs for mission requirement formulation in support of the ARRM Requirements Closure Technical Interchange Meeting (TIM) in mid-December of 2015, to assist in developing an initial list of potential mission investigations, and to provide input on potential hosted payloads and partnerships. Expertise from the science, engineering, and technology communities was represented in exploring lines of inquiry related to key characteristics of the ARRM reference target asteroid (2008 EV5) for engineering design purposes. As of December 2015, the FAST has been formally retired and the FAST final report was publically released in February of 2016. However, plans have been made to stand up an ARM Investigation Team (IT), which is expected be formed in 2016. The multidisciplinary IT will assist with the definition and support of mission investigations, support ARM program-level and project-level functions, and support NASA Head-quarters interactions with the science and technology

  1. Structural Stability of Asteroids

    Science.gov (United States)

    Hirabayashi, Toshi

    This thesis develops a technique for analyzing the internal structure of an irregularly shaped asteroid. This research focuses on asteroid (216) Kleopatra, a few-hundred-kilometer-sized main belt asteroid spinning about its maximum moment of inertia axis with a rotation period of 5.385 hours, to motivate the techniques. While Ostro et al. [117] reported its dog bone-like shape, estimation of its size has been actively discussed. There are at least three different size estimates: Ostro et al., Descamps et al., and Marchis et al. Descamps et al. reported that (216) Kleopatra has satellites and obtained the mass of this object. This research consists of determination of possible failure modes of (216) Kleopatra and its subsequent detailed stress analysis, with each part including an estimation of the internal structure. The first part of this thesis considers the failure mode of Kleopatra and evaluates the size from it. Possible failure modes are modeled as either material shedding from the surface or plastic failure of the internal structure. The surface shedding condition is met when a zero-velocity curve with the same energy level as one of the dynamical equilibrium points attaches to the surface at the slowest spin period, while the plastic failure condition is characterized by extending the theorem by Holsapple (2008) that the yield condition of the averaged stress over the whole volume is identical to an upper bound for global failure. The prime result shows that while surface shedding does not occur at the current spin period and thus cannot result in the formation of the satellites, the neck may be situated near its plastic deformation state. From the failure condition, we also find that the size estimated by Descamps et al. (2011) is the most structurally stable. The second part of this thesis discusses finite element analyses with an assumption of an elastic-perfectly plastic material and a non-associated flow rule. The yield condition is modeled as the

  2. Families classification including multiopposition asteroids

    Science.gov (United States)

    Milani, Andrea; Spoto, Federica; Knežević, Zoran; Novaković, Bojan; Tsirvoulis, Georgios

    2016-01-01

    In this paper we present the results of our new classification of asteroid families, upgraded by using catalog with > 500,000 asteroids. We discuss the outcome of the most recent update of the family list and of their membership. We found enough evidence to perform 9 mergers of the previously independent families. By introducing an improved method of estimation of the expected family growth in the less populous regions (e.g. at high inclination) we were able to reliably decide on rejection of one tiny group as a probable statistical fluke. Thus we reduced our current list to 115 families. We also present newly determined ages for 6 families, including complex 135 and 221, improving also our understanding of the dynamical vs. collisional families relationship. We conclude with some recommendations for the future work and for the family name problem.

  3. Asteroid Deflection Using a Spacecraft in Restricted Keplerian Motion

    CERN Document Server

    Ketema, Yohannes

    2016-01-01

    A method for asteroid deflection that makes use of a spacecraft moving back and forth on a segment of an appropriate Keplerian orbit about the asteroid is described and evaluated. It is shown that, on average, the spacecraft describing such a trajectory can exert a significantly larger force on the asteroid than e.g. a stationary gravity tractor, thereby reducing the time needed to effect a desired velocity change for the asteroid. Furthermore, the current method does not require canted thrusters on the spacecraft (unlike a stationary gravity tractor), markedly reducing the amount of fuel needed to create a given change in the asteroid velocity. In addition, the method allows for the simultaneous use of several spacecraft, further strengthening the overall tugging effect on the asteroid, and distributing the thrust requirement among the spacecraft.

  4. Linking Scarce Asteroid Astrometry At Discovery And Over Apparitions

    Science.gov (United States)

    Granvik, Mikael; Muinonen, K.

    2007-10-01

    Currently about 10% of all asteroid astrometry reported to the Minor Planet Center (MPC) belong to single-night observation sets. Similarly, roughly 10-15% of the asteroids that have received a designation by the MPC have been observed only during one apparition. Due to the scarce astrometry, which leads to large ephemeris uncertainties, most of the underlying asteroids have essentially been lost. However, by linking a few of these scarce data sets, the underlying object can be recovered. Due to challenges such as short observational time spans, a small amount of observed positions, astrometric uncertainties, long linking intervals, parallax, and --- particularly in the future --- massive amounts of data, the linking task is highly non-trivial. We have developed novel linking methods capable of dealing with the challenges posed both by the short-term linking of single-night astrometry and by the long-term linking of single-apparition astrometry. The methods are based on statistical inversion of asteroid astrometry for the probability-density functions of the orbital elements. Through the use of dimensionality-reduction techniques and efficient data structures the methods scale as Ο(n log n), where n is the number of included observation sets. The methods are thus suitable for future large-scale surveys which anticipate a substantial increase in the astrometric data rate. We will present the methods and the key techniques used, with an emphasis on the new long-term linking method. We will also show results obtained for both simulated and real astrometry. The focus will be on the results obtained when searching for linkages among the tens of thousands of real observation sets spanning less than two days.

  5. The Nature of C Asteroid Regolith from Meteorite Observations

    Science.gov (United States)

    Zolensky, M.; Mikouchi, T.; Hagiya, K.; Ohsumi, K.; Komatsu, M.; Jenniskens, P.; Le, L.; Yin, Q.-Z; Kebukawa, Y.; Fries, M.

    2013-01-01

    Regolith from C (and related) asteroid bodies are a focus of the current missions Dawn at Ceres, Hayabusa 2 and OSIRIS REx. An asteroid as large as Ceres is expected to be covered by a mature regolith, and as Hayabusa demonstrated, flat and therefore engineeringly-safe ponded deposits will probably be the sampling sites for both Hayabusa 2 and OSIRIS REx. Here we examine what we have learned about the mineralogy of fine-grained asteroid regolith from recent meteorite studies and the examination of the samples harvested from asteroid Itokawa by Hayabusa.

  6. Current Status Of Velocity Field Surveys: A Consistency Check

    CERN Document Server

    Sarkar, D; Watkins, R; Sarkar, Devdeep; Feldman, Hume A.

    2006-01-01

    We present a statistical analysis comparing the bulk--flow measurements for six recent peculiar velocity surveys, namely, ENEAR, SFI, RFGC, SBF and the Mark III singles and group catalogs. We study whether the bulk--flow estimates are consistent with each other and construct the full three dimensional bulk--flow vectors. The method we discuss could be used to test the consistency of all velocity field surveys. We show that although these surveys differ in their geometry and measurement errors, their bulk flow vectors are expected to be highly correlated and in fact show impressive agreement in all cases. Our results suggest that even though the surveys we study target galaxies of different morphology and use different distance measures, they all reliably reflect the same underlying large-scale flow.

  7. Sensitivity of the Asteroid Redirect Robotic Mission (ARRM) to Launch Date and Asteroid Stay Time

    Science.gov (United States)

    Mcguire, Melissa L.; Burke, Laura M.; McCarty, Steven L.; Strange, Nathan J.; Qu, Min; Shen, Haijun; Vavrina, Matthew A.

    2017-01-01

    National Aeronautics and Space Administrations (NASAs) proposed Asteroid Redirect Mission (ARM) is being designed to robotically capture and then redirect an asteroidal boulder mass into a stable orbit in the vicinity of the moon, where astronauts would be able to visit and study it. The current reference trajectory for the robotic portion, ARRM, assumes a launch on a Delta IV H in the end of the calendar year 2021, with a return for astronaut operations in cislunar space in 2026. The current baseline design allocates 245 days of stay time at the asteroid for operations and boulder collection. This paper outlines analysis completed by the ARRM mission design team to understand the sensitivity of the reference trajectory to launch date and asteroid stay time.

  8. Asteroid models from the Lowell photometric database

    Science.gov (United States)

    Ďurech, J.; Hanuš, J.; Oszkiewicz, D.; Vančo, R.

    2016-03-01

    Context. Information about shapes and spin states of individual asteroids is important for the study of the whole asteroid population. For asteroids from the main belt, most of the shape models available now have been reconstructed from disk-integrated photometry by the lightcurve inversion method. Aims: We want to significantly enlarge the current sample (~350) of available asteroid models. Methods: We use the lightcurve inversion method to derive new shape models and spin states of asteroids from the sparse-in-time photometry compiled in the Lowell Photometric Database. To speed up the time-consuming process of scanning the period parameter space through the use of convex shape models, we use the distributed computing project Asteroids@home, running on the Berkeley Open Infrastructure for Network Computing (BOINC) platform. This way, the period-search interval is divided into hundreds of smaller intervals. These intervals are scanned separately by different volunteers and then joined together. We also use an alternative, faster, approach when searching the best-fit period by using a model of triaxial ellipsoid. By this, we can independently confirm periods found with convex models and also find rotation periods for some of those asteroids for which the convex-model approach gives too many solutions. Results: From the analysis of Lowell photometric data of the first 100 000 numbered asteroids, we derived 328 new models. This almost doubles the number of available models. We tested the reliability of our results by comparing models that were derived from purely Lowell data with those based on dense lightcurves, and we found that the rate of false-positive solutions is very low. We also present updated plots of the distribution of spin obliquities and pole ecliptic longitudes that confirm previous findings about a non-uniform distribution of spin axes. However, the models reconstructed from noisy sparse data are heavily biased towards more elongated bodies with high

  9. 5m Main Belt Asteroid Population Estimation Using Vesta Imagery

    Science.gov (United States)

    Rynders, Michael; Trilling, David E.

    2016-10-01

    The Main Belt is the largest source of Near-Earth asteroids, but objects 2 pixels in diameter that were counted in a 33km 2 region to give a crater density. By knowing the crater density and making some reasonable assumptions about the orbital distribution of asteroids and the age of Vesta's surface, an estimate of the population of small asteroids in the inner main belt was made. It was found that the inner region of the main asteroid belt contains approximately 20 billion asteroids larger than 5 m. These results agree well with the measured inner Main Belt Size distribution derived by the Wide-field Infrared Survey Explorer, WISE (Masiero et al. 2011).

  10. NASA's Human Mission to a Near-Earth Asteroid: Landing on a Moving Target

    Science.gov (United States)

    Smith, Jeffrey H.; Lincoln, William P.; Weisbin, Charles R.

    2011-01-01

    This paper describes a Bayesian approach for comparing the productivity and cost-risk tradeoffs of sending versus not sending one or more robotic surveyor missions prior to a human mission to land on an asteroid. The expected value of sample information based on productivity combined with parametric variations in the prior probability an asteroid might be found suitable for landing were used to assess the optimal number of spacecraft and asteroids to survey. The analysis supports the value of surveyor missions to asteroids and indicates one launch with two spacecraft going simultaneously to two independent asteroids appears optimal.

  11. NASA's Human Mission to a Near-Earth Asteroid: Landing on a Moving Target

    Science.gov (United States)

    Smith, Jeffrey H.; Lincoln, William P.; Weisbin, Charles R.

    2011-01-01

    This paper describes a Bayesian approach for comparing the productivity and cost-risk tradeoffs of sending versus not sending one or more robotic surveyor missions prior to a human mission to land on an asteroid. The expected value of sample information based on productivity combined with parametric variations in the prior probability an asteroid might be found suitable for landing were used to assess the optimal number of spacecraft and asteroids to survey. The analysis supports the value of surveyor missions to asteroids and indicates one launch with two spacecraft going simultaneously to two independent asteroids appears optimal.

  12. Failure mode diagram of rubble pile asteroids: Application to (25143) asteroid Itokawa

    Science.gov (United States)

    Hirabayashi, Masatoshi; Scheeres, Daniel J.

    2016-01-01

    Proposing a diagram which shows the variation in asteroidal failure as a function of a spin period, later called the failure mode diagram, this paper considers the failure modes and conditions of asteroid (25143) Itokawa. This diagram is useful to describe when and where failure occurs in an asteroid. Assuming that Itokawa is homogeneous, we use a plastic finite element code to obtain the diagram for this object. The results show that if the bulk cohesive strength is less than 0.1 Pa, Itokawa experiences compressional failure on the neck surface at the current spin period 12.1 hours. At a spin period shorter than 4.5 hours, tension across the neck causes this asteroid to split into two components. It is also found that if the breakup spin period is longer than 5.2 hours, their motion is bounded. This implies that once Itokawa splits, the components may escape from one another.

  13. Self-Checks In Spreadsheets: A Survey Of Current Practice

    CERN Document Server

    Colver, David

    2010-01-01

    A common application of spreadsheets is the development of models that deliver projections of the future financial statements of companies established to pursue ventures that are subject to project financing. A survey of 11 such spreadsheets prepared by a range of organisations shows that the amount of self-testing included in such models ranges between one formula of testing for each three formulae of calculation, down to essentially no self-testing at all.

  14. Corrective shoes for children: a survey of current practice.

    Science.gov (United States)

    Staheli, L T; Giffin, L

    1980-01-01

    A survey of shoe-prescribing practices for children was taken among pediatricians, orthopaedists, pediatric orthopaedists, and podiatrists. Opinions differed significantly regarding the usefulness of shoe modifications for common pediatric lower limb and foot problems. Parents' attitudes toward children's shoes were also surveyed. Pediatricians and pediatric orthopaedists tended to prescribe corrective shoes less often than did orthopaedists and podiatrists. High topped shoes are not necessary to promote normal foot development, in the opinion of 85% of those surveyed; however, high topped shoes were often recommended for infants because they slip off less easily. Preferences for Thomas heels, scaphoid pads, reverse lasts, straight lasts, wedges, torque heels, and shoe lifts for problems including flexible flat feet, metatarsus adductus, intoeing, bow legs, knock knees, and leg length inequalities were delineated among the four groups treating children's feet. The authors conclude that whereas studies show that shoe modifications are of questionable value in the problems discussed, corrective shoes are often prescribed when regular shoes would be more appropriate and economical.

  15. Space weathering of asteroids

    CERN Document Server

    Shestopalov, D I; Cloutis, E A

    2012-01-01

    Analysis of laboratory experiments simulating space weathering optical effects on atmosphereless planetary bodies reveals that the time needed to alter the spectrum of an ordinary chondrite meteorite to resemble the overall spectral shape and slope of an S-type asteroid is about ~ 0.1 Myr. The time required to reduce the visible albedo of samples to ~ 0.05 is ~ 1 Myr. Since both these timescales are much less than the average collisional lifetime of asteroids larger than several kilometers in size, numerous low-albedo asteroids having reddish spectra with subdued absorption bands should be observed instead of an S-type dominated population. It is not the case because asteroid surfaces cannot be considered as undisturbed, unlike laboratory samples. We have estimated the number of collisions occurring in the time of 105 yr between asteroids and projectiles of various sizes and show that impact-activated motions of regolith particles counteract the progress of optical maturation of asteroid surfaces. Continual r...

  16. 78 FR 54622 - Proposed Information Collection; Comment Request; Current Population Survey, Annual Social and...

    Science.gov (United States)

    2013-09-05

    ... Census Bureau Proposed Information Collection; Comment Request; Current Population Survey, Annual Social... concerning the Annual Social and Economic Supplement (ASEC) to be conducted in conjunction with the February, March, and April Current Population Survey (CPS). The Census Bureau has conducted this...

  17. Exploration of the Moon and Asteroids by Secondary Students

    Science.gov (United States)

    Shaner, A. J.; Bakerman, M. N.; Buxner, S.

    2016-12-01

    Since 2014, the Exploration of the Moon and Asteroids by Secondary Students, or ExMASS, program provides an opportunity for students to participate in authentic scientific research. The ExMASS program is an effort managed by the Center for Lunar Science and Exploration (CLSE). Led by the Lunar and Planetary Institute and Johnson Space Center, CLSE is one of nine teams comprising NASA's Solar System Exploration Research Virtual Institute (SSERVI). Over the course of one academic year, 10 teams of U.S. high school students conduct their own scientific investigations of Earth's Moon, or asteroids, with guidance from a scientist advisor. The program includes two elements: 1) two guided-inquiry introductory research activities that builds student knowledge of current lunar/asteroid science and lunar/asteroid data, and 2) an open-inquiry research project in which the students apply their knowledge to a self-defined project. Because the research is student-driven, it is not necessarily original research; original research is therefore not required. However, one team's research has been published in a professional journal. At the end of the school year, teams submit an abstract and research poster which are scored by a panel a judges. The top four scoring teams gather virtually to give short presentations to the judges. After presentations and time for Q&A, the judges choose one team to present in person at the Exploration Science Forum (ESF). The posters of all finalist schools are displayed at the ESF. The ExMASS program is evaluated by collecting data on changes in students' lunar/asteroid content knowledge, student attitudes toward science and science careers, and student perceptions of the processes of science in which their team participated. Exit surveys for teachers, students, and advisors are also distributed at the end of each program year to gather general feedback about the program and its impact. Results of this data from the first two years of the Ex

  18. Geropsychology Mentoring: A Survey of Current Practices and Perceived Needs

    Science.gov (United States)

    Fiske, Amy; Zimmerman, Jennifer A.; Scogin, Forrest

    2011-01-01

    The need for clinical geropsychologists currently exceeds their availability, and this imbalance is expected to worsen along with the impending growth in the older adult population. Effective geropsychology mentoring may be helpful in meeting this challenge. However, little is known about mentoring within clinical geropsychology. The present paper…

  19. The Dynamical Evolution of the Asteroid Belt

    CERN Document Server

    Morbidelli, Alessandro; O'Brien, David P; Minton, David A; Bottke, William F

    2015-01-01

    The asteroid belt is the leftover of the original planetesimal population in the inner solar system. However, currently the asteroids have orbits with all possible values of eccentricities and inclinations compatible with long-term dynamical stability, whereas the initial planetesimal orbits should have been quasi-circular and almost co-planar. The total mass in the asteroid population is a small fraction of that existing primordially. Also, asteroids with different chemical/mineralogical properties are not ranked in an orderly manner with mean heliocentric distance as one could expect from the existence of a radial gradient of the temperature in the proto-planetary disk, but they are partially mixed. These properties show that the asteroid belt has been severely sculpted by one or a series of processes during its lifetime. This paper reviews the processes that have been proposed so far, discussing the properties that they explain and the problems that they are confronted with. Emphasis is paid to the interpl...

  20. NEOWISE REACTIVATION MISSION YEAR ONE: PRELIMINARY ASTEROID DIAMETERS AND ALBEDOS

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, C. R.; Cutri, R. M. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Mainzer, A.; Masiero, J.; Bauer, J.; Kramer, E.; Sonnett, S.; Stevenson, R. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ (United States); Wright, E. L., E-mail: cnugent@ipac.caltech.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

    2015-12-01

    We present preliminary diameters and albedos for 7956 asteroids detected in the first year of the NEOWISE Reactivation mission. Of those, 201 are near-Earth asteroids and 7755 are Main Belt or Mars-crossing asteroids. 17% of these objects have not been previously characterized using the Near-Earth Object Wide-field Infrared Survey Explorer, or “NEOWISE” thermal measurements. Diameters are determined to an accuracy of ∼20% or better. If good-quality H magnitudes are available, albedos can be determined to within ∼40% or better.

  1. Photometry and shape modeling of Mars crosser asteroid (1011 Laodamia

    Directory of Open Access Journals (Sweden)

    Apostolovska G.

    2014-01-01

    Full Text Available An analysis of photometric observations of Mars crosser asteroid 1011 Laodamia conducted at Bulgarian National Astronomical Observatory Rozhen over a twelve year interval (2002, 2003, 2004, 2006, 2007, 2008, 2011, 2012 and 2013 is made. Based on the obtained lightcurves the spin vector, sense of rotation, and preliminary shape model of (1011 Laodamia have been determined using the lightcurve inversion method. The aim of this investigation is to increase the set of asteroids with known spin and shape parameters and to contribute in improving the model in combination with other techniques and sparse data produced by photometric asteroid surveys such as Pan-STARRS or GAIA.

  2. Asteroids - NeoWs API

    Data.gov (United States)

    National Aeronautics and Space Administration — NeoWs (Near Earth Object Web Service) is a RESTful web service for near earth Asteroid information. With NeoWs a user can: search for Asteroids based on their...

  3. 2015 Barcelona Asteroid Day

    CERN Document Server

    Gritsevich, Maria; Palme, Herbert

    2017-01-01

    This volume is a compilation of the research presented at the International Asteroid Day workshop which was celebrated at Barcelona on June 30th, 2015. The proceedings discuss the beginning of a new era in the study and exploration of the solar system’s minor bodies. International Asteroid Day commemorates the Tunguska event of June 30th, 1908. The workshop’s goal was to promote the importance of dealing proactively with impact hazards from space. Multidisciplinary experts contributed to this discussion by describing the nature of comets and asteroids along with their offspring, meteoroids. New missions to return material samples of asteroids back to Earth such as Osiris-REx and Hayabusa 2, as well as projects like AIM and DART which will test impact deflection techniques for Potentially Hazardous Asteroids encounters were also covered. The proceedings include both an outreach level to popularize impact hazards and a scientific character which covers the latest knowledge on these topics, as well as offeri...

  4. Digital Tracking Observations Can Discover Asteroids Ten Times Fainter than Conventional Searches

    CERN Document Server

    Heinze, Aren; Trollo, Joseph

    2015-01-01

    We describe digital tracking, a method for asteroid searches that greatly increases the sensitivity of a telescope to faint unknown asteroids. It has been previously used to detect faint Kuiper Belt objects using the Hubble Space Telescope and large ground-based instruments, and to find a small, fast-moving asteroid during a close approach to Earth. We complement this earlier work by developing digital tracking methodology for detecting asteroids using large-format CCD imagers. We demonstrate that the technique enables the ground-based detection of large numbers of new faint asteroids. Our methodology resolves or circumvents all major obstacles to the large-scale application of digital tracking for finding main belt and near-Earth asteroids. We find that for both asteroid populations, digital tracking can deliver a factor of ten improvement over conventional searches. Digital tracking has long been standard practice for deep Kuiper Belt surveys, but even there our methodology enables deeper integrations than ...

  5. A Targeted Search for Trojan Asteroids in Kepler Lightcurves

    Science.gov (United States)

    Bordenave, David; Ballard, Sarah

    2015-01-01

    'Trojan' asteroids, or asteroids trapped in stable gravitational positions preceding and trailing a planet in its orbit, accompany almost every planet of our Solar System. They were captured into their current locations in the early stages of our solar system's formation, and their presence hints at the dynamical history of bodies orbiting the Sun. However, we have no reason to assume that our own planets are alone in possessing Trojan asteroids. NASA's Kepler mission, launched in 2009, has been instrumental in the recent search for exoplanets. It has identified thousands of new worlds to date. However, exo-Trojan asteroids have as-yet eluded detection. If asteroids are captured at both Lagrangian points, their folded transit signature is not strictly periodic (since transits occur 1/6th of the planetary period before and after transit), and may be missed by traditional search algorithms. Our targeted search, at the predicted times of transit, is best suited for identifying candidate Trojans. Moreover, we have focused our investigation upon the set of Kepler Objects of Interest (KOIs) that we predict will be most fruitful for Trojan detection. However, if we are unable to detect these Trojan asteroids, we will be able to set limiting constraints on the presence of asteroids in exoplanetary systems. Observations of these Trojan asteroids, or the lack thereof, would give insight to the evolution and migration models of these systems.

  6. Typography and layout of technical reports - Survey of current practices

    Science.gov (United States)

    Pinelli, T. E.; Cordle, V. M.; Mccullough, R.

    1985-01-01

    As part of a review of the NASA Langley Research Center scientific and technical information program, 50 technical reports from industry, research institutions, and government agencies were systematically examined and analyzed to determine current usage and practice in regard to (1) typography, including composition method, type style, type size, and margin treatment; (2) graphic design, including layout and imposition of material on the page; and (3) physical media, including paper, ink, and binding methods. The results indicate that approximately 50 percent of the reports were typeset, 70 percent used Roman (serif) type, 80 percent used 10- or 11-point type for text, 60 percent used a ragged right-hand margin, slightly more than half used paragraph indentation, 75 percent used a single-column layout, 65 percent had one or more figures or tables placed perpendicular to (not aligned with) the text, and perfect binding was the most frequently used binding method.

  7. Geography of the asteroid belt

    Science.gov (United States)

    Zellner, B. H.

    1978-01-01

    The CSM classification serves as the starting point on the geography of the asteroid belt. Raw data on asteroid types are corrected for observational biases (against dark objects, for instance) to derive the distribution of types throughout the belt. Recent work on family members indicates that dynamical families have a true physical relationship, presumably indicating common origin in the breakup of a parent asteroid.

  8. The Active Asteroids

    CERN Document Server

    Jewitt, Dave

    2011-01-01

    Some asteroids eject dust, unexpectedly producing transient, comet-like comae and tails. First ascribed to the sublimation of near-surface water ice, mass losing asteroids (also called "main-belt comets") can in fact be driven by a surprising diversity of mechanisms. In this paper, we consider eleven dynamical asteroids losing mass, in nine of which the ejected material is spatially resolved. We address mechanisms for producing mass loss including rotational instability, impact ejection, electrostatic repulsion, radiation pressure sweeping, dehydration stresses and thermal fracture, in addition to the sublimation of ice. In two objects (133P and 238P) the repetitive nature of the observed activity leaves ice sublimation as the only reasonable explanation while, in a third ((596) Scheila), a recent impact is the cause. Another impact may account for activity in P/2010 A2 but this tiny object can also be explained as having shed mass after reaching rotational instability. Mass loss from (3200) Phaethon is proba...

  9. How to find metal-rich asteroids

    CERN Document Server

    Harris, Alan W

    2014-01-01

    The metal content of asteroids is of great interest, not only for theories of their origins and the evolution of the solar system but, in the case of near-Earth objects (NEOs), also for impact mitigation planning and endeavors in the field of planetary resources. However, since the reflection spectra of metallic asteroids are largely featureless, it is difficult to identify them and relatively few are known. We show how data from the Wide-field Infrared Survey Explorer (WISE)/NEOWISE thermal-infrared survey and similar surveys, fitted with a simple thermal model, can reveal objects likely to be metal rich. We provide a list of candidate metal-rich NEOs. Our results imply that future infrared surveys with the appropriate instrumentation could discover many more metal-rich asteroids, providing valuable data for assessment of the impact hazard and the potential of NEOs as reservoirs of vital materials for future interplanetary space activities and, eventually perhaps, for use on Earth.

  10. Concept Design and Operation of an Asteroid Mining Vehicle

    Science.gov (United States)

    Claus, M.; Kumanan, D.

    2014-04-01

    The objective of this extended abstract is to provide an outline of the space activities undertaken within the astronautics group at Kingston University, before moving on to the current asteroid mining research.

  11. Manuel's asteroid disruption technique.

    Science.gov (United States)

    John, Manuel; Ipe, Abraham; Jacob, Ivan

    2015-06-01

    A seventy-year-old male presented with dense asteroid hyalosis in both eyes. He had undergone cataract extraction in one eye 3 years ago, and the other eye had immature cataract. Both the autorefractor and dilated streak retinoscopy did not give readings and subjective visual improvement could not be achieved. Immediately following YAG posterior capsulotomy and anterior vitreous asteroid disruption, the vision improved to 20/20 with recordable auto refractor and streak retinoscopy values. Our initial experience indicates that the treatment is simple, safe and effective but needs controlled and prospective studies to confirm its long-term safety.

  12. Asteroid Redirect Crewed Mission Nominal Design and Performance

    Science.gov (United States)

    Condon, Gerald; williams, Jacob

    2014-01-01

    Mission (ARCM) nominal design and performance costs associated with an Orion based crewed rendezvous mission to a captured asteroid in an Earth-Moon DRO. The ARM study includes two fundamental mission phases: 1) The Asteroid Redirect Robotic Mission (ARRM) and 2) the ARCM. The ARRM includes a solar electric propulsion based robotic asteroid return vehicle (ARV) sent to rendezvous with a selected near Earth asteroid, capture it, and return it to a DRO in the Earth-Moon vicinity. The DRO is selected over other possible asteroid parking orbits due to its achievability (by both the robotic and crewed vehicles) and by its stability (e.g., no orbit maintenance is required). After the return of the asteroid to the Earth-Moon vicinity, the ARCM is executed and carries a crew of two astronauts to a DRO to rendezvous with the awaiting ARV with the asteroid. The outbound and inbound transfers employ lunar gravity assist (LGA) flybys to reduce the Orion propellant requirement for the overall nominal mission, which provides a nominal mission with some reserve propellant for possible abort situations. The nominal mission described in this report provides a better understanding of the mission considerations as well as the feasibility of such a crewed mission, particularly with regard to spacecraft currently undergoing development, such as the Orion vehicle and the Space Launch System (SLS).

  13. Current Trends in Communication Graduate Degrees: Survey of Communications, Advertising, PR, and IMC Graduate Programs

    Science.gov (United States)

    Quesenberry, Keith A.; Coolsen, Michael K.; Wilkerson, Kristen

    2015-01-01

    A survey of 61 master's degree advertising programs reveals significant trends in program titles, curriculum design, course delivery, and students served. The results provide insight for current and planned master's degree programs as research predicts a continued increase in demand for master's education over the next decade. Survey results are…

  14. A Survey of Current and Projected Ethical Dilemmas of Rehabilitation Counselors

    Science.gov (United States)

    Hartley, Michael T.; Cartwright, Brenda Y.

    2016-01-01

    Purpose: This study surveyed current and projected ethical dilemmas of rehabilitation counselors. Method: As a mixed-methods approach, the study used both quantitative and qualitative analyses. Results: Of the 211 participants who completed the survey, 116 (55.0%) reported an ethical dilemma. Based on the descriptions, common themes involved roles…

  15. Current Trends in Communication Graduate Degrees: Survey of Communications, Advertising, PR, and IMC Graduate Programs

    Science.gov (United States)

    Quesenberry, Keith A.; Coolsen, Michael K.; Wilkerson, Kristen

    2015-01-01

    A survey of 61 master's degree advertising programs reveals significant trends in program titles, curriculum design, course delivery, and students served. The results provide insight for current and planned master's degree programs as research predicts a continued increase in demand for master's education over the next decade. Survey results are…

  16. GLOBEC NEP Northern California Current Cetacean Survey Data, NH0005, 0007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GLOBEC (GLOBal Ocean ECosystems Dynamics) NEP (Northeast Pacific) Northern California Current Cetacean Survey Data from R/V New Horizon cruises NH0005 and 0007....

  17. Survey and evaluation of current and potential coal beneficiation processes

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S. P.N.; Peterson, G. R.

    1979-03-01

    Coal beneficiation is a generic term used for processes that prepare run-of-mine coal for specific end uses. It is also referred to as coal preparation or coal cleaning and is a means of reducing the sulfur and the ash contents of coal. Information is presented regarding current and potential coal beneficiation processes. Several of the processes reviewed, though not yet commercial, are at various stages of experimental development. Process descriptions are provided for these processes commensurate with the extent of information and time available to perform the evaluation of these processes. Conceptual process designs, preliminary cost estimates, and economic evaluations are provided for the more advanced (from a process development hierarchy viewpoint) processes based on production levels of 1500 and 15,000 tons/day (maf) of cleaned product coal. Economic evaluations of the coal preparation plants are conducted for several project financing schemes and at 12 and 15% annual after-tax rates of return on equity capital. A 9% annual interest rate is used on the debt fraction of the plant capital. Cleaned product coal prices are determined using the discounted cash flow procedure. The study is intended to provide information on publicly known coal beneficiation processes and to indicate the relative costs of various coal beneficiation processes. Because of severe timeconstraints, several potential coal beneficiation processes are not evaluated in great detail. It is recommended that an additional study be conducted to complement this study and to more fully appreciate the potentially significant role of coal beneficiation in the clean burning of coal.

  18. Current approaches to the diagnosis and treatment of idiopathic pulmonary fibrosis in Europe: the AIR survey

    Directory of Open Access Journals (Sweden)

    Vincent Cottin

    2014-06-01

    Full Text Available This review presents the results of the 2013 Advancing IPF Research (AIR survey, which assessed current approaches to the diagnosis and treatment of idiopathic pulmonary fibrosis (IPF by experienced physicians. A total of 149 physicians, predominantly from European countries, replied to the 28-question survey. The results of the AIR survey were compared with a similar survey of 509 French pulmonologists conducted by the French National Reference Centre and the Network of Regional Competence Centres for Rare Lung Diseases. A number of positive findings emerged from the AIR survey, including the high level of multidisciplinary team involvement in both diagnosis and management. This survey, when taken together with the French survey, suggests that there is still a need to improve earlier diagnosis of IPF.

  19. Asteroid Control and Resource Utilization

    Science.gov (United States)

    Paterson, G.; Radice, G.; Sanchez, J.-P.

    Asteroids are materials rich small solar system bodies which are prime candidates for rendezvous and mining. Up until now much attention has been focused on methods of destroying or deflecting potentially hazardous asteroids from colliding with the Earth. Recently however the concept of asteroid capture has been suggested whereby the asteroid is returned to an orbit close to the Earth before mining can begin. This paper aims to provide a comprehensive introduction to the field for new researchers and to put forward a number of novel strategies for asteroid control.

  20. The Advanced Jovian Asteroid Explorer (AJAX)

    Science.gov (United States)

    Murchie, S. L.; Adams, E. Y.; Mustard, J. F.; Rivkin, A.; Peplowski, P. N.

    2015-12-01

    The Advanced Jovian Asteroid eXplorer (AJAX) is the first mission to characterize the geology, morphology, geophysical properties, and chemistry of a Trojan asteroid. The Decadal Survey outlined a notional New Frontiers class Trojan asteroid rendezvous mission to conduct geological, elemental composition, mineralogical, and geophysical investigations. AJAX, our Discovery mission proposal, addresses the Decadal Survey science goals by using a focused payload and an innovative mission design. By responding to the most important questions about the Trojan asteroids, AJAX advances our understanding of all of the Solar System. Are these objects a remnant population of the local primordial material from which the outer planets and their satellites formed, or did they originate in the Kuiper Belt? Landed measurements of major and minor elements test hypotheses for the Trojan asteroid origin, revealing the outer Solar System dynamical history. How and when were prebiotic materials delivered to the terrestrial planets? AJAX's landed measurements include C and H concentrations, necessary to determine their inventories of volatiles and organic compounds, material delivered to the inner Solar System during the Late Heavy Bombardment. What chemical and geological processes shaped the small bodies that merged to form the planets in our Solar System? AJAX investigates the asteroid internal structure, geology, and regolith by using global high-resolution stereo and multispectral imaging, determining density and estimating interior porosity by measuring gravity, and measuring regolith mechanical properties by landing. AJAX's science phase starts with search for natural satellites and dust lifted by possible cometary activity and shape and pole position determination. AJAX descends to lower altitudes for global mapping, and conducts a low flyover for high-resolution surface characterization and measurement of hydrogen abundance. Finally, it deploys a small landed package, which

  1. Rotation Properties of Small Jovian Trojan Asteroids

    Science.gov (United States)

    French, Linda M.; Stephens, Robert D.; James, David; Coley, Daniel R.; Warner, Brian D.; Rohl, Derrick

    2016-10-01

    Jovian Trojan asteroids are of interest both as objects in their own right (we have no spectral analogs among meteorite samples) and as possible relics of Solar System formation. Asteroid lightcurves can give information about processes that have affected a group of asteroids; they can also give information about the density of the objects when enough lightcurves have been collected. We have been carrying out a survey of Trojan lightcurve properties for comparison with small asteroids and with comets. In a recent paper (French et al. 2015) we presented evidence that a significant number of Trojans have rotation periods greater than 24 hours. We will report our latest results and compare them with results of sparsely-sampled lightcurves from the Palomar Transient Factory (Waszczak et al. 2015). LF, RS, and DR were visiting astronomers at Cerro Tololo Interamerican Observatory, operated by AURA under contract with the NSF, and with the SMARTS Consortium at CTIO. This research was sponsored by NSF Planetary Astronomy grant 1212115.ReferencesFrench, L.M. et al. 2015. Icarus 254, pp. 1-17.Waszczak, A. et al. 2015. A.J. 150, Issue 3, I.D. 35.

  2. Spectral Classification of NEOWISE Observed Near-Earth Asteroids

    Science.gov (United States)

    Desira, Christopher

    2017-01-01

    Near-Earth asteroids (NEAs) allow us to determine the properties of the smallest solar system bodies in the sub-kilometer size range. Large (>few km) NEAs have albedos which span a wide range from ~0.05 to ~0.3 and are known to correlate with asteroid composition, determined by analysing the shape of their optical reflectance spectra. It is, however, still unknown how this relationship extends into the sub-kilometer population.NEOWISE has performed a thermal infrared survey that provides the largest inventory to date of well-determined sizes and albedos for NEAs, including many in the sub-km population. This provides an opportunity to test the albedo-surface composition correlation in a new size regime. If it is found to hold, then a simple optical spectrum can give a well-constrained albedo and size estimate without the need for thermal IR measurements.The sizes and composition of many more sub-km sized NEAs are needed to aid in the understanding of the formation/evolution of the inner solar system and the characterisation of potentially hazardous objects, possible mission targets and even commercial mining operations.We obtained optical spectra of sub-kilometer NEOWISE-observed NEAs using the 1.5m Tillinghast telescope and the FAST spectrograph at the Whipple Observatory on Mt Hopkins, Arizona. We performed a taxonomic classification to identify their likely composition and combined this with NEOWISE data to look for known correlations between main belt asteroid spectral types and their optical albedos. Additionally, we tested the robustness of current data reduction methods in order to increase our confidence in the spectral classifications of NEAs.

  3. Threat Mitigation: The Asteroid Tugboat

    CERN Document Server

    Schweickart, R; Durda, D; Hut, P; Chapman, Clark; Durda, Dan; Hut, Piet; Schweickart, Russell

    2006-01-01

    The Asteroid Tugboat (AT) is a fully controlled asteroid deflection concept using a robotic spacecraft powered by a high efficiency, electric propulsion system (ion or plasma) which docks with and attaches to the asteroid, conducts preliminary operations, and then thrusts continuously parallel to the asteroid velocity vector until the desired velocity change is achieved. Based on early warning, provided by ground tracking and orbit prediction, it would be deployed a decade or more prior to a potential impact. On completion of the initial rendezvous with the near-Earth object (NEO) the AT would first reduce the uncertainty in the orbit of the asteroid via Earth tracking of its radio transponder while it is station keeping with the asteroid. If on analysis of tracking data a deflection is required the AT would execute a reconnaissance phase collecting and processing information about the physical characteristics of the asteroid to support subsequent operations. The AT would then dock at the appropriate pole (i....

  4. The Asteroid Frontier

    Science.gov (United States)

    Mcfadden, Lucyann A.

    2012-01-01

    There are many ways of studying the Asteroid Frontier as a scientist. In my career, I have used large telescopes atop a 14,000 ft mountain top observatory in Hawaii, used the Hubble Space Telescope in orbit around the Earth, traveled to Antarctica to collect meteorites sitting on the ice waiting for them to be recovered by scientists for scientific investigation, walked the desert with 50 students from University of Khartoum searching for fragments of an asteroid that collided with earth, exploded in the upper atmosphere and rained fragments on the desert floor. Most recently, I have looked at one of the largest Main Belt Asteroids named (4) Vesta through the eyes of a robotic spacecraft named Dawn, exploring the asteroid frontier. I will share my adventures, place the thrill of scientific exploration through NASA's solar system exploration program in context and provide opportunities for students to engage in NASA's exciting missions to expand scientific understanding of Earth and the Universe in which we live

  5. Asteroids, meteorites, and comets

    CERN Document Server

    Elkins-Tanton, Linda T

    2010-01-01

    Asteroids, Comets, and Meteorites provides students, researchers, and general readers with the most up-to-date information on this fascinating field. From the days of the dinosaurs to our modern environment, this book explores all aspects of these cosmic invaders.

  6. Asteroid-Generated Tsunami and Impact Risk

    Science.gov (United States)

    Boslough, M.; Aftosmis, M.; Berger, M. J.; Ezzedine, S. M.; Gisler, G.; Jennings, B.; LeVeque, R. J.; Mathias, D.; McCoy, C.; Robertson, D.; Titov, V. V.; Wheeler, L.

    2016-12-01

    The justification for planetary defense comes from a cost/benefit analysis, which includes risk assessment. The contribution from ocean impacts and airbursts is difficult to quantify and represents a significant uncertainty in our assessment of the overall risk. Our group is currently working toward improved understanding of impact scenarios that can generate dangerous tsunami. The importance of asteroid-generated tsunami research has increased because a new Science Definition Team, at the behest of NASA's Planetary Defense Coordinating Office, is now updating the results of a 2003 study on which our current planetary defense policy is based Our group was formed to address this question on many fronts, including asteroid entry modeling, tsunami generation and propagation simulations, modeling of coastal run-ups, inundation, and consequences, infrastructure damage estimates, and physics-based probabilistic impact risk assessment. We also organized the Second International Workshop on Asteroid Threat Assessment, focused on asteroid-generated tsunami and associated risk (Aug. 23-24, 2016). We will summarize our progress and present the highlights of our workshop, emphasizing its relevance to earth and planetary science. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

  7. Asteroid Sufaces/Regoliths Deduced by Remote Sensing

    Science.gov (United States)

    Price, S.

    Resolved imagery on a small number of asteroids provides information about the size, density and surface relief from which inferences may be made regarding their regoliths; Eros Eros is the best studied asteroid in this regard However, remote sensing is necessary to deduce properties for the large majority of objects. These techniques include: spectroscopy and multi-spectral band photometry, which provide clues as to the chemical composition of the surface, infrared (plus visible) radiometry, from which physical bulk and surface properties may be inferred through the derived albedo and thermal inertia, and radar, which permits one to deduce the near surface bulk density. This article reviews what these techniques have revealed about the surface characteristics of asteroids. Asteroids have been classified by the broad emissive properties of the surface as indicated by filter band photometry. Recently, observations from large scale surveys - 2MASS (Denis to a lesser extent) and the Sloan Digital Sky Survey - provided taxonomic classifications for thousands of asteroids. The mineralogy is more secure at higher spectral resolution. Silicates on the surface of asteroids have been inferred from IRAS, ISO and Kuiper Airborne infrared spectra. Infrared radiometry has been used to derive the albedos and diameters of ~2300 asteroids observed by IRAS and MSX. The simplified Standard Thermal Model (STM) works well for main belt asteroids. The model assumes that the asteroid does not rotate and is in instantaneous thermal equilibrium between absorbed sunlight and emitted radiation. Empirical factors for flux enhancement (beaming) and phase function are adopted. There is a dichotomy between large and small asteroids in this database. About 20% of the asteroids with diameters inertia, rotation rate, orientation of the rotation pole, surface roughness and degree of cratering. A complex model is required to account for all the variables. Such a model was developed using full

  8. The Hawaii trails project: comet-hunting in the main asteroid belt

    Science.gov (United States)

    Hsieh, H. H.

    2009-10-01

    Context: The mysterious solar system object 133P/(7968) Elst-Pizarro is dynamically asteroidal, yet displays recurrent comet-like dust emission. Two scenarios were hypothesized to explain this unusual behavior: 1) 133P is a classical comet from the outer solar system that has evolved onto a main-belt orbit or 2) 133P is a dynamically ordinary main-belt asteroid on which subsurface ice has recently been exposed. If 1) is correct, the expected rarity of a dynamical transition onto an asteroidal orbit implies that 133P could be alone in the main belt. In contrast, if 2) is correct, other icy main-belt objects should exist and could also exhibit cometary activity. Aims: Believing 133P to be a dynamically ordinary, yet icy main-belt asteroid, I set out to test the primary prediction of the hypothesis: that 133P-like objects should be common and could be found by an appropriately designed observational survey. Methods: I conducted just such a survey - the Hawaii Trails Project - of selected main-belt asteroids in a search for objects displaying cometary activity. Optical observations were made of targets selected from among the Themis, Koronis, and Veritas asteroid families, the Karin asteroid cluster, and low-inclination, kilometer-scale outer-belt asteroids, using the Lulin 1.0 m, small and moderate aperture research telescope system (SMARTS) 1.0 m, University of Hawaii 2.2 m, southern astrophysical research (SOAR) 4.1 m, Gemini North 8.1 m, Subaru 8.2 m, and Keck I 10 m telescopes. Results: I made 657 observations of 599 asteroids, discovering one active object now known as 176P/LINEAR, leading to the identification of the new cometary class of main-belt comets (MBCs). These results suggest that there could be ~100 currently active MBCs among low-inclination, kilometer-scale outer-belt asteroids. Physically and statistically, MBC activity is consistent with initiation by meter-sized impactors. The estimated rate of impacts and sizes of resulting active sites, however

  9. Asteroid Kinetic Impactor Missions

    Science.gov (United States)

    Chesley, Steven

    2015-08-01

    Asteroid impact missions can be carried out as a relatively low-cost add-ons to most asteroid rendezvous missions and such impact experiments have tremendous potential, both scientifically and in the arena of planetary defense.The science returns from an impactor demonstration begin with the documentation of the global effects of the impact, such as changes in orbit and rotation state, the creation and dissipation of an ejecta plume and debris disk, and morphological changes across the body due to the transmission of seismic waves, which might induce landslides and toppling of boulders, etc. At a local level, an inspection of the impact crater and ejecta blanket reveals critical material strength information, as well as spectral differences between the surface and subsurface material.From the planetary defense perspective, an impact demonstration will prove humankind’s capacity to alter the orbit of a potentially threatening asteroid. This technological leap comes in two parts. First, terminal guidance systems that can deliver an impactor with small errors relative to the ~100-200 meter size of a likely impactor have yet to be demonstrated in a deep space environment. Second, the response of an asteroid to such an impact is only understood theoretically due to the potentially significant dependence on the momentum carried by escaping ejecta, which would tend to enhance the deflection by tens of percent and perhaps as much as a factor of a few. A lack of validated understanding of momentum enhancement is a significant obstacle in properly sizing a real-world impactor deflection mission.This presentation will describe the drivers for asteroid impact demonstrations and cover the range of such concepts, starting with ESA’s pioneering Don Quijote mission concept and leading to a brief description of concepts under study at the present time, including the OSIRIS-REx/ISIS, BASiX/KIX and AIM/DART (AIDA) concepts.

  10. Near-Earth asteroids orbit propagation with Gaia observations

    CERN Document Server

    Bancelin, D; Thuillot, W

    2016-01-01

    Gaia is an astrometric mission that will be launched in 2013 and set on L2 point of Lagrange. It will observe a large number of Solar System Objets (SSO) down to magnitude 20. The Solar System Science goal is to map thousand of Main Belt asteroids (MBAs), Near Earth Objects (NEOs) (including comets) and also planetary satellites with the principal purpuse of orbital determination (better than 5 mas astrometric precision), determination of asteroid mass, spin properties and taxonomy. Besides, Gaia will be able to discover a few objects, in particular NEOs in the region down to the solar elongation 45{\\deg} which are harder to detect with current ground-based surveys. But Gaia is not a follow-up mission and newly discovered objects can be lost if no ground-based recovery is processed. The purpose of this study is to quantify the impact of Gaia data for the known NEAs population and to show how to handle the problem of these discoveries when faint number of observations and thus very short arc is provided.

  11. A Search for Fast Optical Transients in the Pan-STARRS1 Medium-Deep Survey: M-Dwarf Flares, Asteroids, Limits on Extragalactic Rates, and Implications for LSST

    Science.gov (United States)

    Berger, E.; Leibler, C. N.; Chornock, R.; Rest, A.; Foley, R. J.; Soderberg, A. M.; Price, P. A.; Burgett, W. S.; Chambers, K. C.; Flewelling, H.; Huber, M. E.; Magnier, E. A.; Metcalfe, N.; Stubbs, C. W.; Tonry, J. L.

    2013-12-01

    We present a search for fast optical transients (τ ~ 0.5 hr-1 day) using repeated observations of the Pan-STARRS1 Medium-Deep Survey (PS1/MDS) fields. Our search takes advantage of the consecutive g P1 r P1 observations (16.5 minutes in each filter), by requiring detections in both bands, with non-detections on preceding and subsequent nights. We identify 19 transients brighter than 22.5 AB mag (S/N >~ 10). Of these, 11 events exhibit quiescent counterparts in the deep PS1/MDS templates that we identify as M4-M9 dwarfs at d ≈ 0.2-1.2 kpc. The remaining eight transients lack quiescent counterparts, exhibit mild but significant astrometric shifts between the g P1 and r P1 images, colors of (g - r)P1 ≈ 0.5-0.8 mag, non-varying light curves, and locations near the ecliptic plane with solar elongations of about 130°, which are all indicative of main-belt asteroids near the stationary point of their orbits. With identifications for all 19 transients, we place an upper limit of R FOT(τ ~ 0.5 hr) factor of 30-50 times lower than previous limits; the limit for a timescale of ~1 day is R FOT events are limited to M ≈ -10 to ≈ - 14 mag for a timescale of ~0.5 hr to ~1 day, while relativistic sources (e.g., gamma-ray bursts, magnetar-powered transients) can reach much larger luminosities. The resulting volumetric rates are Motivated by the results of our search, we discuss strategies for identifying fast optical transients in the Large Synoptic Survey Telescope main survey, and reach the optimistic conclusion that the veil of foreground contaminants can be lifted with the survey data, without the need for expensive follow-up observations.

  12. Evidence for the Nature of Space Weathering Spectral Signatures on Low Albedo Asteroids

    Science.gov (United States)

    Lantz, Cateline; Clark, B. E.; Barucci, M. A.

    2012-10-01

    We address an existing problem in understanding the reflected light spectral signatures of carbonaceous (low-albedo) asteroids. We know from observations of the moon and high-albedo asteroids that interplanetary surface processes (solar wind and micrometeorite bombardment) can alter the spectral properties of silicates. The problem is that we don’t understand how carbonaceous surfaces respond to surface processes. The question is, what are the spectral signatures of surface processes on low albedo asteroids? To answer this question, we need to study reflected light spectra of asteroid subsurface materials, and compare them with asteroid surface materials. In this work, we assume that primitive asteroids are the parent bodies of carbonaceous chondrites. We begin with a fairly well-established meteorite-asteroid link: several studies have found evidence that links the CM meteorites with the Ch/Cgh asteroids [Hiroi et ao. 1996; Fornasier et al. 1999]. Assuming this link, we reason that differences between spectra of particulate samples of the CM meteorites and spectra of the regolith of the asteroids can be due to either differences in textural properties, or differences caused by surface processes on the asteroid. Previous work has resulted in contradictory predictions. Asteroid color survey data analyzed by Lazzarin et al. (2006) predicted spectral reddening for low albedo asteroids. Laser irradiation experiments by Moroz et al. (1996; 2004; 2004b) indicated both reddening and blueing of various degrees. Our initial results indicate spectral blueing of up to 50%, with little to no concurrent albedo change. We used telescopic observations of 43 Ch and Cgh-type asteroids (0.4 to 2.5 microns) from Binzel, DeMeo, et al. (MIT) and Fornasier et al. (Obs. Paris). We compare them statistically with 106 CM meteorite spectra from RELAB. The goal of this work is to predict what the OSIRIS-REx mission will see at B-type asteroid (101955) 1999RQ36.

  13. Asteroids' physical models from combined dense and sparse photometry and scaling of the YORP effect by the observed obliquity distribution

    CERN Document Server

    Hanuš, J; Brož, M; Marciniak, A; Warner, B D; Pilcher, F; Stephens, R; Behrend, R; Carry, B; Čapek, D; Antonini, P; Audejean, M; Augustesen, K; Barbotin, E; Baudouin, P; Bayol, A; Bernasconi, L; Borczyk, W; Bosch, J -G; Brochard, E; Brunetto, L; Casulli, S; Cazenave, A; Charbonnel, S; Christophe, B; Colas, F; Coloma, J; Conjat, M; Cooney, W; Correira, H; Cotrez, V; Coupier, A; Crippa, R; Cristofanelli, M; Dalmas, Ch; Danavaro, C; Demeautis, C; Droege, T; Durkee, R; Esseiva, N; Esteban, M; Fagas, M; Farroni, G; Fauvaud, M; Fauvaud, S; Del Freo, F; Garcia, L; Geier, S; Godon, C; Grangeon, K; Hamanowa, H; Heck, N; Hellmich, S; Higgins, D; Hirsch, R; Husarik, M; Itkonen, T; Jade, O; Kamiński, K; Kankiewicz, P; Klotz, A; Koff, R A; Kryszczyńska, A; Kwiatkowski, T; Laffont, A; Leroy, A; Lecacheux, J; Leonie, Y; Leyrat, C; Manzini, F; Martin, A; Masi, G; Matter, D; Michałowski, J; Michałowski, M J; Michałowski, T; Michelet, J; Michelsen, R; Morelle, E; Mottola, S; Naves, R; Nomen, J; Oey, J; Ogloza, W; Oksanen, A; Oszkiewicz, D; Pääkkönen, P; Paiella, M; Pallares, H; Paulo, J; Pavic, M; Payet, B; Polińska, M; Polishook, D; Poncy, R; Revaz, Y; Rinner, C; Rocca, M; Roche, A; Romeuf, D; Roy, R; Saguin, H; Salom, P A; Sanchez, S; Santacana, G; Santana-Ros, T; Sareyan, J -P; Sobkowiak, K; Sposetti, S; Starkey, D; Stoss, R; Strajnic, J; Teng, J -P; Tregon, B; Vagnozzi, A; Velichko, F P; Waelchli, N; Wagrez, K; Wücher, H; 10.1051/0004-6361/201220701

    2013-01-01

    The larger number of models of asteroid shapes and their rotational states derived by the lightcurve inversion give us better insight into both the nature of individual objects and the whole asteroid population. With a larger statistical sample we can study the physical properties of asteroid populations, such as main-belt asteroids or individual asteroid families, in more detail. Shape models can also be used in combination with other types of observational data (IR, adaptive optics images, stellar occultations), e.g., to determine sizes and thermal properties. We use all available photometric data of asteroids to derive their physical models by the lightcurve inversion method and compare the observed pole latitude distributions of all asteroids with known convex shape models with the simulated pole latitude distributions. We used classical dense photometric lightcurves from several sources and sparse-in-time photometry from the U.S. Naval Observatory in Flagstaff, Catalina Sky Survey, and La Palma surveys (...

  14. 313 new asteroid rotation periods from Palomar Transient Factory observations

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chan-Kao; Ip, Wing-Huen; Lin, Hsing-Wen; Cheng, Yu-Chi; Ngeow, Chow-Choong; Yang, Ting-Chang [Institute of Astronomy, National Central University, Jhongli, Taiwan (China); Waszczak, Adam [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Kulkarni, Shrinivas R.; Levitan, David; Sesar, Branimir; Prince, Thomas A. [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Laher, Russ; Surace, Jason, E-mail: rex@astro.ncu.edu.tw [Spitzer Science Center, California Institute of Technology, M/S 314-6, Pasadena, CA 91125 (United States)

    2014-06-10

    A new asteroid rotation period survey has been carried out by using the Palomar Transient Factory (PTF). Twelve consecutive PTF fields, which covered an area of 87 deg{sup 2} in the ecliptic plane, were observed in the R band with a cadence of ∼20 minutes during 2013 February 15-18. We detected 2500 known asteroids with a diameter range of 0.5 km ≤D ≤ 200 km. Of these, 313 objects had highly reliable rotation periods and exhibited the 'spin barrier' at ∼2 hr. In contrast to the flat spin-rate distribution of the asteroids with 3 km ≤D ≤ 15 km shown by Pravec et al., our results deviated somewhat from a Maxwellian distribution and showed a decrease at the spin rate greater than 5 rev day{sup –1}. One superfast rotator candidate and two possible binary asteroids were also found in this work.

  15. 313 new asteroid rotation periods from Palomar Transient Factory observations

    CERN Document Server

    Chang, Chan-Kao; Lin, Hsing-Wen; Cheng, Yu-Chi; Ngeow, Chow-Choong; Yang, Ting-Chang; Waszczak, Adam; Kulkarni, Shrinivas R; Levitan, David; Sesar, Branimir; Laher, Russ; Surace, Jason; Prince, Thomas A

    2014-01-01

    A new asteroid rotation period survey have been carried out by using the Palomar Transient Factory (PTF). Twelve consecutive PTF fields, which covered an area of 87 deg$^2$ in the ecliptic plane, were observed in $R$ band with a cadence of $\\sim$20 min during February 15--18, 2013. We detected 2500 known asteroids with a diameter range of 0.5 km $\\leq D \\leq$ 200 km. Of these, 313 objects had highly reliable rotation periods and exhibited the "spin barrier" at $\\sim2$ hours. In contrast to the flat spin rate distribution of the asteroids with 3 km $\\leq D \\leq$ 15 km shown by Pravec et al. (2008), our results deviated somewhat from a Maxwellian distribution and showed a decrease at the spin rate greater than 5 rev/day. One super-fast-rotator candidate and two possible binary asteroids were also found in this work.

  16. Detecting extrasolar asteroid belts through their microlensing signatures

    Science.gov (United States)

    Lake, Ethan; Zheng, Zheng; Dong, Subo

    2017-02-01

    We propose that extrasolar asteroid belts can be detected through their gravitational microlensing signatures. Asteroid belt + star lens systems create so-called 'pseudo-caustics', regions in the source plane where the magnification exhibits a finite but discontinuous jump. These features allow such systems to generate distinctive signatures in the microlensing light curves for a wide range of belt configurations, with source trajectories as far as tenths of the Einstein ring radius from the centre of the lens. Sample light curves for a range of asteroid belt parameters are presented. In the near future, space-based microlensing surveys like WFIRST, which will have the power of detecting per cent-level changes in microlensing light curves even with subminute exposure times, may be able to discover extrasolar asteroid belts with masses of the order of an earth mass.

  17. A deep space inventory tour of the main asteroid belt

    DEFF Research Database (Denmark)

    Gibbings, Alison; Bowles, Neil; Snodgrass, Colin

    2016-01-01

    A consortium of international scientists and industry partners are proposing the Main Belt Inventory Mission as a candidate in the next forthcoming ESA medium class mission call. The inventory mission will characterise a broad range of statistically significant asteroid samples throughout the Main...... Asteroid Belt (MAB). A 0.5 m aperture space-based telescope will conduct a detailed spectroscopic survey, observing thousands of objects from a range of 0.1-0.5 AU, and perform basic flybys of pre-selected targets. Each flyby will target an asteroid of a different size, taxonomic (sub)classes and orbital...... families, where spatially resolved spectral mapping and spectroscopy will be performed. Smaller and fainter passing targets will also be discovered, through opportunistic science, with dedicated star tracker-like cameras. Examining the compositional diversity across the asteroid population will provide...

  18. Planning the Minimum Time and Optimal Survey Trajectory for Autonomous Underwater Vehicles in Uncertain Current

    Directory of Open Access Journals (Sweden)

    Michael A. Hurni

    2015-12-01

    Full Text Available The authors develop an approach to a “best” time path for Autonomous Underwater Vehicles conducting oceanographic measurements under uncertain current flows. The numerical optimization tool DIDO is used to compute hybrid minimum time and optimal survey paths for a sample of currents between ebb and flow. A simulated meta-experiment is performed where the vehicle traverses the resulting paths under different current strengths per run. The fastest elapsed time emerges from a payoff table. A multi-objective function is then used to weigh the time to complete a mission versus measurement inaccuracy due to deviation from the desired survey path.

  19. Near Earth Asteroid Characterization for Threat Assessment

    Science.gov (United States)

    Dotson, Jessie; Mathias, Donovan; Wheeler, Lorien; Wooden, Diane; Bryson, Kathryn; Ostrowski, Daniel

    2017-01-01

    Physical characteristics of NEAs are an essential input to modeling behavior during atmospheric entry and to assess the risk of impact but determining these properties requires a non-trivial investment of time and resources. The characteristics relevant to these models include size, density, strength and ablation coefficient. Some of these characteristics cannot be directly measured, but rather must be inferred from related measurements of asteroids and/or meteorites. Furthermore, for the majority of NEAs, only the basic measurements exist so often properties must be inferred from statistics of the population of more completely characterized objects. The Asteroid Threat Assessment Project at NASA Ames Research Center has developed a probabilistic asteroid impact risk (PAIR) model in order to assess the risk of asteroid impact. Our PAIR model and its use to develop probability distributions of impact risk are discussed in other contributions to PDC 2017 (e.g., Mathias et al.). Here we utilize PAIR to investigate which NEA characteristics are important for assessing the impact threat by investigating how changes in these characteristics alter the damage predicted by PAIR. We will also provide an assessment of the current state of knowledge of the NEA characteristics of importance for asteroid threat assessment. The relative importance of different properties as identified using PAIR will be combined with our assessment of the current state of knowledge to identify potential high impact investigations. In addition, we will discuss an ongoing effort to collate the existing measurements of NEA properties of interest to the planetary defense community into a readily accessible database.

  20. Capture of Asteroids and Transport of Asteroid Materials to Earth

    Science.gov (United States)

    Chiu, Hong-Yee; no Team

    2014-01-01

    Recently there has been much discussion on the capture of asteroids or mining the asteroids. While the technology might be years away, in this paper we will discuss an energy efficient method to transport either a small asteroid or materials gathered from asteroids to the Earth. In particular, I will concentrate on a large and nearby asteroid, 8 Flora in the Flora Family. Generally, asteroids are located between 2 to 3 AU (astronomical unit) from the Earth, and in transporting materials from asteroids to the Earth, an energy equivalent of the gravitational potential energy difference between the Earth and the asteroids to the Sun. This amount of potential energy is a sizable fraction of the orbital kinetic energy of the Earth around the Sun. This amount of energy is considerable. In this paper I propose to use the planet Mars as a medium to remove much of the gravitational energy difference. In the case of the asteroid 8 Flora, it is only necessary to decelerate the asteroid mate- rials by a small decrement, of the order of 3 km/sec. This decrement could even be achieved (pending on the availability of technology) by mechanical devices such as catapults on 8 Flora. It is also proposed to separate a pair of contact asteroid binaries by using impulse propulsion, and to propel one component of the separated asteroids to pass by Mars to be decelerated to reach the Earth orbit and captured by the Earth or the Moon. The plausibility of this ambitious project will be discussed. The author is NASA-GSFC Astrophysicist, Retired.

  1. EURONEAR - Data Mining of Asteroids and Near Earth Asteroids

    OpenAIRE

    Vaduvescu, O.; Curelaru, L.; Birlan, M.; Bocsa, G.; Serbanescu, L.; Tudorica, A.; Berthier, J.

    2009-01-01

    Besides new observations, mining old photographic plates and CCD image archives represents an opportunity to recover and secure newly discovered asteroids, also to improve the orbits of Near Earth Asteroids (NEAs), Potentially Hazardous Asteroids (PHAs) and Virtual Impactors (VIs). These are the main research aims of the EURONEAR network. As stated by the IAU, the vast collection of image archives stored worldwide is still insufficiently explored, and could be mined for known NEAs and other a...

  2. NASA's Asteroid Redirect Mission: Overview and Status

    Science.gov (United States)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Brophy, John; Mazanek, Dan; Muirhead, Brian

    A major element of the National Aeronautics and Space Administration’s (NASA) new Asteroid Initiative is the Asteroid Redirect Mission (ARM). This concept was first proposed in 2011 during a feasibility study at the Keck Institute for Space Studies (KISS)[1] and is under consideration for implementation by NASA. The ARM involves sending a high-efficiency (ISP 3000 s), high-power (40 kW) solar electric propulsion (SEP) robotic vehicle that leverages technology developed by NASA’s Space Technology Mission Directorate (STMD) to rendezvous with a near-Earth asteroid (NEA) and return asteroidal material to a stable lunar distant retrograde orbit (LDRO)[2]. There are two mission concepts currently under study, one that captures an entire 7 - 10 meter mean diameter NEA[3], and another that retrieves a 1 - 10 meter mean diameter boulder from a 100+ meter class NEA[4]. Once the retrieved asteroidal material is placed into the LDRO, a two person crew would launch aboard an Orion capsule to rendezvous and dock with the robotic SEP vehicle. After docking, the crew would conduct two extra-vehicular activities (EVA) to collect asteroid samples and deploy instruments prior to Earth return. The crewed portion of the mission is expected to last approximately 25 days and would represent the first human exploration mission beyond low-Earth orbit (LEO) since the Apollo program. The ARM concept leverages NASA’s activities in Human Exploration, Space Technology, and Planetary Defense to accomplish three primary objectives and several secondary objectives. The primary objective relevant to Human Exploration is to gain operational experience with vehicles, systems, and components that will be utilized for future deep space exploration. In regard to Space Technology, the ARM utilizes advanced SEP technology that has high power and long duration capabilities that enable future missions to deep space destinations, such as the Martian system. With respect to Planetary Defense, the ARM

  3. Predicting close encounters between asteroids with the STB software

    Science.gov (United States)

    Lilly (Schunova), Eva; Jonas, Jeff; Srivatsa, Mudhakar; Ganti, Raghu; Agrawal, Dakshi; Denneau, Larry; Kratky, Martin; Wainscoat, Richard J.

    2015-11-01

    We have developed a method that can quickly and efficiently calculate close encounters between all known asteroids both in the past and the future. Only several hundred asteroids out of more than 690,000 have their masses currently known. The most accurate values are from direct measurements by in situ visits (e.g. Dawn at Ceres and Vesta (Russell et al. 2012, Science 336, 6082, pp. 684), Hayabusa at Itokawa (Abe et al. 2006, Science 312, 5778, pp. 1344-1349)) followed by measurements of binary systems and also from mutual orbit perturbations during close encounters between a handful of the largest MBAs.We used software called “Space Time Box” (STB) invented by IBM capable of efficiently determine co-located entities in 3D space and time. Orbits from the MPCORB.DAT database were placed into selected STB granularity with 1 day and 0.05 AU-wide bins. By determining and only tracking asteroids co-located within a selected minimal distance the computational requirements were significantly reduced. Selected instances of co-location were then provided as an input for a numerical integrator SWIFT with 8 planets as perturbers and were integrated until desired epoch with a 0.5 and 1 day timestep. We then used interpolation for the specified time window to check if the positions of asteroids intersect or are within a certain distance parameter.Using the STB optimization we calculated close encounters between years 2014 and 2039. These events offer the opportunity to search in the survey archives for potential collisions and carefully select the events for mass determination based on their minimal approach distance, angle and mass ratio of participating objects. A follow-up astrometric campaign would ensure improvement of the mass determination precision. Predicted future events can also be directly observed in the real time with optical and IR telescopes in search for collisions or mass loss.As an example we present one close encounter event observed with the University

  4. Active Asteroids: Main-Belt Comets and Disrupted Asteroids

    CERN Document Server

    Hsieh, Henry H

    2015-01-01

    The study of active asteroids has attracted a great deal of interest in recent years since the recognition of main-belt comets (which orbit in the main asteroid belt, but exhibit comet-like activity due to the sublimation of volatile ices) as a new class of comets in 2006, and the discovery of the first disrupted asteroids (which, unlike MBCs, exhibit comet-like activity due to a physical disruption such as an impact or rotational destabilization, not sublimation) in 2010. In this paper, I will briefly discuss key areas of interest in the study of active asteroids.

  5. Spacewatch discovery of near-Earth asteroids

    Science.gov (United States)

    Gehrels, Tom

    1992-01-01

    Our overall scientific goal is to survey the solar system to completion - that is, to find the various populations and to study their statistics, interrelations, and origins. The practical benefit to SERC is that we are finding Earth-approaching asteroids that are accessible for mining. Our system can detect Earth-approachers in the 1-km size range even when they are far away, and can detect smaller objects when they are moving rapidly past Earth. Until Spacewatch, the size range of 6-300 meters in diameter for the near-Earth asteroids was unexplored. This important region represents the transition between the meteorites and the larger observed near-Earth asteroids. One of our Spacewatch discoveries, 1991 VG, may be representative of a new orbital class of object. If it is really a natural object, and not man-made, its orbital parameters are closer to those of the Earth than we have seen before; its delta V is the lowest of all objects known thus far. We may expect new discoveries as we continue our surveying, with fine-tuning of the techniques.

  6. White Paper on Multicarrier Excitation of Multipactor Breakdown: A Survey of Current Methods and Research Opportunities

    Science.gov (United States)

    2015-06-18

    AEROSPACE REPORT NO. TOR-2015-02548 White Paper on Multicarrier Excitation of Multipactor Breakdown: A Survey of Current Methods and...voltage phenomena where the verification power level is chosen such that the maximum instantaneous operational voltage in the component is excited . In...analysis methods under investigation for multicarrier excitation threshold prediction based on a survey of the research literature. In general, this

  7. Asteroid family ages

    CERN Document Server

    Spoto, Federica; Knezevic, Zoran

    2015-01-01

    A new family classification, based on a catalog of proper elements with $\\sim 384,000$ numbered asteroids and on new methods is available. For the $45$ dynamical families with $>250$ members identified in this classification, we present an attempt to obtain statistically significant ages: we succeeded in computing ages for $37$ collisional families. We used a rigorous method, including a least squares fit of the two sides of a V-shape plot in the proper semimajor axis, inverse diameter plane to determine the corresponding slopes, an advanced error model for the uncertainties of asteroid diameters, an iterative outlier rejection scheme and quality control. The best available Yarkovsky measurement was used to estimate a calibration of the Yarkovsky effect for each family. The results are presented separately for the families originated in fragmentation or cratering events, for the young, compact families and for the truncated, one-sided families. For all the computed ages the corresponding uncertainties are pro...

  8. Asteroid Impact Monitoring

    Science.gov (United States)

    Milani, A.

    2006-06-01

    Some asteroids and comets with Earth-crossing orbit may impact our planet, thus we need to be able to identify the cases which could have a dangerous close approach within a century. This must be done as soon as such an asteroid is discovered, allowing for follow up observations which might contradict the impact possibility, and in the worst case to organize mitigation, possibly including deflection. The mathematical problem of predicting possible impacts, even with very low probabilities, has been solved by our group in the last few years. This paper presents the basic theory of these impact prediction, and discusses how they are practically used in the impact monitoring systems now operational, in particular the CLOMON2 robot of the Universities of Pisa and Valladolid.

  9. Asteroid impact monitoring

    Directory of Open Access Journals (Sweden)

    Milani A.

    2006-01-01

    Full Text Available Some asteroids and comets with Earth-crossing orbit may impact our planet, thus we need to be able to identify the cases which could have a dangerous close approach within a century. This must be done as soon as such an asteroid is discovered, allowing for follow up observations which might contradict the impact possibility, and in the worst case to organize mitigation, possibly including deflection. The mathematical problem of predicting possible impacts, even with very low probabilities, has been solved by our group in the last few years. This paper presents the basic theory of these impact prediction, and discusses how they are practically used in the impact monitoring systems now operational, in particular the CLOMON2 robot of the Universities of Pisa and Valladolid.

  10. Asteroid Surface Geophysics

    CERN Document Server

    Murdoch, Naomi; Schwartz, Stephen R; Miyamoto, Hideaki

    2015-01-01

    The regolith-covered surfaces of asteroids preserve records of geophysical processes that have occurred both at their surfaces and sometimes also in their interiors. As a result of the unique micro-gravity environment that these bodies posses, a complex and varied geophysics has given birth to fascinating features that we are just now beginning to understand. The processes that formed such features were first hypothesised through detailed spacecraft observations and have been further studied using theoretical, numerical and experimental methods that often combine several scientific disciplines. These multiple approaches are now merging towards a further understanding of the geophysical states of the surfaces of asteroids. In this chapter we provide a concise summary of what the scientific community has learned so far about the surfaces of these small planetary bodies and the processes that have shaped them. We also discuss the state of the art in terms of experimental techniques and numerical simulations that...

  11. Silicates in Alien Asteroids

    Science.gov (United States)

    2009-01-01

    This plot of data from NASA's Spitzer Space Telescopes shows that asteroid dust around a dead 'white dwarf' star contains silicates a common mineral on Earth. The data were taken primarily by Spitzer's infrared spectrograph, an instrument that breaks light apart into its basic constituents. The yellow dots show averaged data from the spectrograph, while the orange triangles show older data from Spitzer's infrared array camera. The white dwarf is called GD 40.

  12. Silicates in Alien Asteroids

    Science.gov (United States)

    2009-01-01

    This plot of data from NASA's Spitzer Space Telescopes shows that asteroid dust around a dead 'white dwarf' star contains silicates a common mineral on Earth. The data were taken primarily by Spitzer's infrared spectrograph, an instrument that breaks light apart into its basic constituents. The yellow dots show averaged data from the spectrograph, while the orange triangles show older data from Spitzer's infrared array camera. The white dwarf is called GD 40.

  13. [SWOT Analysis of the National Survey on Current Status of Major Human Parasitic Diseases in China].

    Science.gov (United States)

    ZHU, Hui-hui; ZHOU, Chang-hai; CHEN, Ying-dan; ZANG, Wei; XIAO, Ning; ZHOU, Xiao-nong

    2015-10-01

    The National Survey on Current Status of Major Human Parasitic Diseases in China has been carried out since 2014 under the organization of the National Health and Family Planning Commission of the People's Republic of China. The National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (NIPD, China CDC) provided technical support and was responsible for quality control in this survey. This study used SWOT method to analyze the strengths, weaknesses, opportunities and threats that were encountered by he NIPD, China CDC during the completion of the survey. Accordingly, working strategies were proposed to facilitate the future field work.

  14. Modeling of Fragmentation of Asteroids

    Science.gov (United States)

    Agrawal, Parul; Prabhu, Dinesh K.; Carlozzi, Alexander; Hart, Kenneth; Bryson, Katie; Sears, Derek

    2015-01-01

    The objective of this study is to understand fragmentation and fracture of a given asteroid and mechanisms of break-up. The focus of the present work is to develop modeling techniques for stony asteroids in 10m-100m range to answer two questions: 1) What is the role of material makeup of an asteroid in the stress distribution? 2)How is stress distribution altered in the presence of pre-existing defects?

  15. NEOWISE Studies of Asteroids with Sloan Photometry: Preliminary Results

    CERN Document Server

    Mainzer, A; Grav, T; Bauer, J; Tholen, D J; McMillan, R S; Wright, E; Spahr, T; Cutri, R M; Walker, R; Mo, W; Watkins, J; Hand, E; Maleszewski, C

    2011-01-01

    We have combined the NEOWISE and Sloan Digital Sky Survey data to study the albedos of 24,353 asteroids with candidate taxonomic classifications derived using Sloan photometry. We find a wide range of moderate to high albedos for candidate S-type asteroids that are analogous to the S-complex defined by previous spectrophotometrically-based taxonomic systems. The candidate C-type asteroids, while generally very dark, have a tail of higher albedos that overlaps the S types. The albedo distribution for asteroids with a photometrically derived Q classification is extremely similar to those of the S types. Asteroids with similar colors to (4) Vesta have higher albedos than the S types, and most have orbital elements similar to known Vesta family members. Finally, we show that the relative reflectance at 3.4 and 4.6 $\\mu$m is higher for D-type asteroids and suggest that their red visible and near-infrared spectral slope extends out to these wavelengths. Understanding the relationship between size, albedo, and taxon...

  16. Analyzing Serendipitous Asteroid Observations in Imaging Data using PHOTOMETRYPIPELINE

    Science.gov (United States)

    Ard, Christopher; Mommert, Michael; Trilling, David E.

    2016-10-01

    Asteroids are nearly ubiquitous in the night sky, making them present in the majority of imaging data taken every night. Serendipitous asteroid observations represent a treasure trove to Solar System researchers: accurate positional measurements of asteroids provide important constraints on their sometimes highly uncertain orbits, whereas calibrated photometric measurements can be used to establish rotational periods, intrinsic colors, or photometric phase curves.We present an add-on to the PHOTOMETRYPIPELINE (PP, github.com/mommermi/photometrypipeline, see Poster presentation 123.42) that identifies asteroids that have been observed serendipitously and extracts astrometry and calibrated photometry for these objects. PP is an open-source Python 2.7 software suite that provides image registration, aperture photometry, photometric calibration, and target identification with only minimal human interaction.Asteroids are identified based on approximate positions that are pre-calculated for a range of dates. Using interpolated coordinates, we identify potential asteroids that might be in the observed field and query their exact positions and positional uncertainties from the JPL Horizons system. The method results in robust astrometry and calibrated photometry for all asteroids in the field as a function of time. Our measurements will supplement existing photometric databases of asteroids and improve their orbits.We present first results using this procedure based on imaging data from the Vatican Advanced Technology Telescope.This work was done in the framework of NAU's REU summer program that is supported by NSF grant AST-1461200. PP was developed in the framework of the "Mission Accessible Near-Earth Object Survey" (MANOS) and is supported by NASA SSO grants NNX15AE90G and NNX14AN82G.

  17. OSIRIS-REx, Returning the Asteroid Sample

    Science.gov (United States)

    Ajluni, Thomas, M.; Everett, David F.; Linn, Timothy; Mink, Ronald; Willcockson, William; Wood, Joshua

    2015-01-01

    This paper addresses the technical aspects of the sample return system for the upcoming Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission. The overall mission design and current implementation are presented as an overview to establish a context for the technical description of the reentry and landing segment of the mission.The prime objective of the OSIRIS-REx mission is to sample a primitive, carbonaceous asteroid and to return that sample to Earth in pristine condition for detailed laboratory analysis. Targeting the near-Earth asteroid Bennu, the mission launches in September 2016 with an Earth reentry date of September 24, 2023.OSIRIS-REx will thoroughly characterize asteroid Bennu providing knowledge of the nature of near-Earth asteroids that is fundamental to understanding planet formation and the origin of life. The return to Earth of pristine samples with known geologic context will enable precise analyses that cannot be duplicated by spacecraft-based instruments, revolutionizing our understanding of the early Solar System. Bennu is both the most accessible carbonaceous asteroid and one of the most potentially Earth-hazardous asteroids known. Study of Bennu addresses multiple NASA objectives to understand the origin of the Solar System and the origin of life and will provide a greater understanding of both the hazards and resources in near-Earth space, serving as a precursor to future human missions to asteroids.This paper focuses on the technical aspects of the Sample Return Capsule (SRC) design and concept of operations, including trajectory design and reentry retrieval. Highlights of the mission are included below.The OSIRIS-REx spacecraft provides the essential functions for an asteroid characterization and sample return mission: attitude control propulsion power thermal control telecommunications command and data handling structural support to ensure successful

  18. AIDA: Asteroid Impact & Deflection Assessment

    Science.gov (United States)

    Cheng, A. F.; Galvez, A.; Carnelli, I.; Michel, P.; Rivkin, A.; Reed, C.

    2012-12-01

    To protect the Earth from a hazardous asteroid impact, various mitigation methods have been proposed, including deflection of the asteroid by a spacecraft impact. AIDA, consisting of two mission elements, the Double Asteroid Redirection Test (DART) and the Asteroid Impact Monitoring (AIM) mission, is a demonstration of asteroid deflection. To date, there has been no such demonstration, and there is major uncertainty in the result of a spacecraft impact onto an asteroid, that is, the amount of deflection produced by a given momentum input from the impact. This uncertainty is in part due to unknown physical properties of the asteroid surface, such as porosity and strength, and in part due to poorly understood impact physics such that the momentum carried off by ejecta is highly uncertain. A first mission to demonstrate asteroid deflection would not only be a major step towards gaining the capability to mitigate an asteroid hazard, but in addition it would return unique information on an asteroid's strength, other surface properties, and internal structure. This information return would be highly relevant to future human exploration of asteroids. We report initial results of the AIDA joint mission concept study undertaken by the Johns Hopkins Applied Physics Laboratory and ESA with support from NASA centers including Goddard, Johnson and Jet Propulsion Laboratory. For AIDA, the DART spacecraft impactor study is coordinated with an ESA study of the AIM mission, which would rendezvous with the same asteroid to measure effects of the impact. Unlike the previous Don Quijote mission study performed by ESA in 2005-2007, DART envisions an impactor spacecraft to intercept the secondary member of a binary near-Earth asteroid. DART includes ground-based observations to measure the deflection independently of the rendezvous spacecraft observations from AIM, which also measures deflection and provides detailed characterization of the target asteroid. The joint mission AIDA

  19. The Size Distribution of the Small Near Earth Asteroids from Spacewatch

    Science.gov (United States)

    Haskell, Halford; Larsen, J.

    2009-01-01

    We are currently in the process of analyzing five years of near earth asteroid detections from the Spacewatch 0.9 meter mosaic camera. These data represent images of approximately 80,000 square degrees which have been surveyed to a limiting magnitude of 21.5 using 20 second integrations. Over 1800 detections of NEAs have been made in a consistent automated fashion with attention to observing conditions. In this poster, we present a careful debiasing of the Spacewatch pointing history following the methods outlined in Jedicke, Larsen and Spahr (2003) and use the data from the survey to calculate the size distribution of small (H > 22) near earth asteroids. For these small sizes we have needed to expand the size of our survey simulations by approximately 100 orders of magnitude in order to represent very small, very hard to detect NEAs. We use the simulations to model the biases of our survey and use the actual detections to explore the size distribution. We present a detailed examination of the "dip" in the size distribution first noticed by Harris (2008) between H=19 and H= 26. Spacewatch is funded by grants from NASA's Near Earth Object Observation and Planetary Astronomy Programs, The Brinson Foundation, the estates of Richard S. Vail and Robert L. Waland and other private individuals.

  20. Delivery of organics to Mars through asteroid and comet impacts

    Science.gov (United States)

    Frantseva, Kateryna; Mueller, Michael; ten Kate, Inge L.; van der Tak, Floris

    2016-10-01

    Despite intensive search, the presence of organic molecules on Mars could only recently be demonstrated, through Curiosity measurements. On the surface of Mars, organics are highly unstable to photodissociation, but may last longer in the subsurface. It is therefore believed that organics observable today were delivered in geologically recent times; possible parent bodies are certain asteroids, comets, and/orinterplanetary dust particles.We are studying how much organics the known asteroids and comets can deliver to Mars. Comets and certain asteroids (C-class) are known to be organic rich.To this end we perform numerical gravity simulations to study impact rates on Mars within the past few Myr. We use the N-body integrator RMVS/Swifter to propagate the Sun and the eight planets from their current positions. We separately add comets and asteroids to the simulations as massless test particles, based on their current orbital distributions. In our asteroid simulations we differentiate between organic-rich (C-class) asteroids and other taxonomic types, using WISE albedo as a proxy. We expect to present first results at the meeting.

  1. EURONEAR - Data Mining of Asteroids and Near Earth Asteroids

    CERN Document Server

    Vaduvescu, O; Birlan, M; Bocsa, G; Serbanescu, L; Tudorica, A; Berthier, J

    2009-01-01

    Besides new observations, mining old photographic plates and CCD image archives represents an opportunity to recover and secure newly discovered asteroids, also to improve the orbits of Near Earth Asteroids (NEAs), Potentially Hazardous Asteroids (PHAs) and Virtual Impactors (VIs). These are the main research aims of the EURONEAR network. As stated by the IAU, the vast collection of image archives stored worldwide is still insufficiently explored, and could be mined for known NEAs and other asteroids appearing occasionally in their fields. This data mining could be eased using a server to search and classify findings based on the asteroid class and the discovery date as "precoveries" or "recoveries". We built PRECOVERY, a public facility which uses the Virtual Observatory SkyBoT webservice of IMCCE to search for all known Solar System objects in a given observation. To datamine an entire archive, PRECOVERY requires the observing log in a standard format and outputs a database listing the sorted encounters of ...

  2. Women in Management: Analysis of Selected Data from the Current Population Survey. Report to Congressional Requesters.

    Science.gov (United States)

    Robertson, Robert E.

    The key characteristics, representation, and salaries of women in management versus those of their male counterparts were examined through an analysis of Current Population Survey data collected in March 1995 and 2000. The study focused on the following 10 industries: communications; public administration; business and repair services;…

  3. Gravitational radiation theory. M.A. Thesis - Rice Univ.; [survey of current research

    Science.gov (United States)

    Wilson, T. L.

    1973-01-01

    A survey is presented of current research in the theory of gravitational radiation. The mathematical structure of gravitational radiation is stressed. Furthermore, the radiation problem is treated independently from other problems in gravitation. The development proceeds candidly through three points of view - scalar, rector, and tensor radiation theory - and the corresponding results are stated.

  4. Group Therapy for School-Aged Children Who Stutter: A Survey of Current Practices

    Science.gov (United States)

    Liddle, Hilary; James, Sarah; Hardman, Margaret

    2011-01-01

    Although group therapy is recommended for school-aged children who stutter (CWS), it is not widely researched. This study aimed to explore this provision, using a postal survey which investigated the current practices of Speech & Language Therapists (SLTs) in the UK. Seventy percent of SLT services provided some group therapy, but the level of…

  5. 78 FR 45910 - Proposed Information Collection; Comment Request; Current Population Survey (CPS) Email Address...

    Science.gov (United States)

    2013-07-30

    ... Census Bureau Proposed Information Collection; Comment Request; Current Population Survey (CPS) Email... concerning the November 2013 Email Address Collection Test Supplement. The Census Bureau and the Bureau of.... We foresee that in the future, we could collect email addresses from our respondents. For those that...

  6. Earth encounters as the origin of fresh surfaces on near-Earth asteroids.

    Science.gov (United States)

    Binzel, Richard P; Morbidelli, Alessandro; Merouane, Sihane; Demeo, Francesca E; Birlan, Mirel; Vernazza, Pierre; Thomas, Cristina A; Rivkin, Andrew S; Bus, Schelte J; Tokunaga, Alan T

    2010-01-21

    Telescopic measurements of asteroids' colours rarely match laboratory reflectance spectra of meteorites owing to a 'space weathering' process that rapidly reddens asteroid surfaces in less than 10(6) years. 'Unweathered' asteroids (those having spectra matching the most commonly falling ordinary chondrite meteorites), however, are seen among small bodies the orbits of which cross inside Mars and the Earth. Various explanations have been proposed for the origin of these fresh surface colours, ranging from collisions to planetary encounters. Less reddened asteroids seem to cross most deeply into the terrestrial planet region, strengthening the evidence for the planetary-encounter theory, but encounter details within 10(6) years remain to be shown. Here we report that asteroids displaying unweathered spectra (so-called 'Q-types') have experienced orbital intersections closer than the Earth-Moon distance within the past 5 x 10(5) years. These Q-type asteroids are not currently found among asteroids showing no evidence of recent close planetary encounters. Our results substantiate previous work: tidal stress, strong enough to disturb and expose unweathered surface grains, is the most likely dominant short-term asteroid resurfacing process. Although the seismology details are yet to be worked out, the identification of rapid physical processes that can produce both fresh and weathered asteroid surfaces resolves the decades-long puzzle of the difference in colour of asteroids and meteorites.

  7. Photometric Study of Selected Asteroids

    Science.gov (United States)

    Shevchenko, Vasilij G.; Velichko, Feodor P.; Checha, Vitaly A.; Krugly, Yurij N.

    2014-07-01

    We performed photometric observations for eleven asteroids. New rotation periods were determined for five asteroids: 2812 Scaltriti (7.596 h), 4716 Urey (6.2 h), 7446 Hadrianus (3.402 h), (26657) 2000 SX293 (2.8 - 3.8 h), and (54063) 2000 GC136 (5.154 h).

  8. Radar Observations of Asteroids

    Science.gov (United States)

    Ostro, S. J.

    2003-05-01

    During the past 25 years, radar investigations have provided otherwise unavailable information about the physical and dynamical properties of more than 200 asteroids. Measurements of the distribution of echo power in time delay and Doppler frequency provide two-dimensional images with spatial resolution as fine as a decameter. Sequences of delay-Doppler images can be used to produce geologically detailed three-dimensional models, to define the rotation state precisely, to constrain the internal density distribution, and to estimate the trajectory of the object's center of mass. Radar wavelengths (4 to 13 cm) and the observer's control of transmitted and received polarizations make the observations sensitive to near-surface bulk density and macroscopic structure. Since delay-Doppler positional measurements are orthogonal to optical angle measurements and typically have much finer fractional precision, they are powerful for refining orbits and prediction ephemerides. Radar astrometry can add decades or centuries to the interval over which an asteroid's close Earth approaches can accurately be predicted and can significantly refine collision probability estimates based on optical astrometry alone. In the highly unlikely case that a small body is on course for an Earth collision in this century, radar reconnaissance would almost immediately distinguish between an impact trajectory and a near miss and would dramatically reduce the difficulty and cost of any effort to prevent the collision. The sizes and rotation periods of radar-detected asteroids span more than four orders of magnitude. These observations have revealed both stony and metallic objects, elongated and nonconvex shapes as well as nearly featureless spheroids, small-scale morphology ranging from smoother than the lunar regolith to rougher than the rockiest terrain on Mars, craters and diverse linear structures, non-principal-axis spin states, contact binaries, and binary systems.

  9. Radar Investigations of Asteroids

    Science.gov (United States)

    Ostro, S.

    2004-05-01

    Radar investigations have provided otherwise unavailable information about the physical and dynamical properties of about 230 asteroids. Measurements of the distribution of echo power in time delay (range) and Doppler frequency (line-of-sight velocity) provide two-dimensional images with spatial resolution as fine as a decameter. Sequences of delay-Doppler images can be used to produce geologically detailed three-dimensional models, to define the rotation state precisely, to constrain the internal density distribution, and to estimate the trajectory of the object's center of mass. Radar wavelengths (4 to 13 cm) and the observer's control of transmitted and received polarizations make the observations sensitive to near-surface bulk density and macroscopic structure. Since delay-Doppler measurements are orthogonal to optical angle measurements and typically have much finer fractional precision, they are powerful for refining orbits and prediction ephemerides. Such astrometric measurements can add decades or centuries to the interval over which an asteroid's close Earth approaches can accurately be predicted and can significantly refine collision probability estimates based on optical astrometry alone. In the highly unlikely case that a small body is on course for an Earth collision in this century, radar reconnaissance would almost immediately distinguish between an impact trajectory and a near miss and would dramatically reduce the difficulty and cost of any effort to prevent the collision. The sizes and rotation periods of radar-detected asteroids span more than four orders of magnitude. The observations have revealed both stony and metallic objects, elongated and nonconvex shapes as well as nearly featureless spheroids, small-scale morphology ranging from smoother than the lunar regolith to rougher than the rockiest terrain on Mars, craters and diverse linear structures, non-principal-axis spin states, contact binaries, and binary systems.

  10. Asteroids and Comets

    CERN Document Server

    Fernandez, Yanga R; Howell, Ellen S; Woodney, Laura M

    2015-01-01

    Asteroids and comets are remnants from the era of Solar System formation over 4.5 billion years ago, and therefore allow us to address two fundamental questions in astronomy: what was the nature of our protoplanetary disk, and how did the process of planetary accretion occur? The objects we see today have suffered many geophysically-relevant processes in the intervening eons that have altered their surfaces, interiors, and compositions. In this chapter we review our understanding of the origins and evolution of these bodies, discuss the wealth of science returned from spacecraft missions, and motivate important questions to be addressed in the future.

  11. New Paradigms For Asteroid Formation

    CERN Document Server

    Johansen, Anders; Cuzzi, Jeffrey N; Morbidelli, Alessandro; Gounelle, Matthieu

    2015-01-01

    Asteroids and meteorites provide key evidence on the formation of planetesimals in the Solar System. Asteroids are traditionally thought to form in a bottom-up process by coagulation within a population of initially km-scale planetesimals. However, new models challenge this idea by demonstrating that asteroids of sizes from 100 to 1000 km can form directly from the gravitational collapse of small particles which have organised themselves in dense filaments and clusters in the turbulent gas. Particles concentrate passively between eddies down to the smallest scales of the turbulent gas flow and inside large-scale pressure bumps and vortices. The streaming instability causes particles to take an active role in the concentration, by piling up in dense filaments whose friction on the gas reduces the radial drift compared to that of isolated particles. In this chapter we review new paradigms for asteroid formation and compare critically against the observed properties of asteroids as well as constraints from meteo...

  12. Science case for the Asteroid Impact Mission (AIM): A component of the Asteroid Impact & Deflection Assessment (AIDA) mission

    Science.gov (United States)

    Michel, Patrick; Cheng, A.; Küppers, M.; Pravec, P.; Blum, J.; Delbo, M.; Green, S. F.; Rosenblatt, P.; Tsiganis, K.; Vincent, J. B.; Biele, J.; Ciarletti, V.; Hérique, A.; Ulamec, S.; Carnelli, I.; Galvez, A.; Benner, L.; Naidu, S. P.; Barnouin, O. S.; Richardson, D. C.; Rivkin, A.; Scheirich, P.; Moskovitz, N.; Thirouin, A.; Schwartz, S. R.; Campo Bagatin, A.; Yu, Y.

    2016-06-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to test the kinetic impactor technique to deflect an asteroid. The European Asteroid Impact Mission (AIM) is set to rendezvous with the asteroid system to fully characterize the smaller of the two binary components a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near-Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Having direct information on the surface and internal properties of small asteroids will allow us to understand how the various processes they undergo work and transform these small bodies as well as, for this particular case, how a binary system forms. Making these measurements from up close and comparing them with ground-based data from telescopes will also allow us to calibrate remote observations and improve our data interpretation of other systems. With DART, thanks to the characterization of the target by AIM, the mission will be the first fully documented impact experiment at asteroid scale, which will include the characterization of the target's properties and the outcome of the impact. AIDA will thus offer a great opportunity to test and refine our understanding and models at the actual scale of an asteroid, and to check whether the current extrapolations of material strength from laboratory-scale targets to the scale of AIDA's target are valid. Moreover, it will offer a first check of the

  13. Asteroid absolute magnitudes and slope parameters

    Science.gov (United States)

    Tedesco, Edward F.

    1991-01-01

    A new listing of absolute magnitudes (H) and slope parameters (G) has been created and published in the Minor Planet Circulars; this same listing will appear in the 1992 Ephemerides of Minor Planets. Unlike previous listings, the values of the current list were derived from fits of data at the V band. All observations were reduced in the same fashion using, where appropriate, a single basis default value of 0.15 for the slope parameter. Distances and phase angles were computed for each observation. The data for 113 asteroids was of sufficiently high quality to permit derivation of their H and G. These improved absolute magnitudes and slope parameters will be used to deduce the most reliable bias-corrected asteroid size-frequency distribution yet made.

  14. BILLIARDS: A Demonstration Mission for Hundred-Meter Class Near Earth Asteroid Disruption

    Science.gov (United States)

    Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent W.

    2015-01-01

    Currently, no planetary defense demonstration mission has ever been flown. While Nuclear Explosive Devices (NEDs) have significantly more energy than a kinetic impactor launched directly from Earth, they present safety and political complications, and therefore may only be used when absolutely necessary. The Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System (BILLIARDS) is a demonstration mission for planetary defense, which is capable of delivering comparable energy to the lower range of NED capabilities in the form of a safer kinetic impactor. A small asteroid (disrupt the larger asteroid. To reduce the cost and complexity, an asteroid pair which has a natural close approach is selected.

  15. A Novel and Simple Means to Estimate Asteroid Thermal Inertia

    Science.gov (United States)

    Drube, Line; Harris, Alan

    2016-10-01

    Calculating accurate values of thermal inertia for asteroids is a difficult process requiring a shape model, thermal-infrared observations of the object obtained over broad ranges of rotation period and aspect angle, and detailed thermophysical modeling. Consequently, reliable thermal inertia values are currently available for relatively few asteroids. On the basis of simple asteroid thermal modeling we have developed an empirical relationship enabling the thermal inertia of an asteroid to be estimated given adequate measurements of its thermal-infrared continuum and knowledge of its spin vector. In particular, our thermal-inertia estimator can be applied to hundreds of objects in the WISE cryogenic archive (limited by the availability of spin vectors). To test the accuracy of our thermal-inertia estimator we have used it to estimate thermal inertia for near-Earth asteroids, main-belt asteroids, Centaurs, and trans-Neptunian objects with known thermal inertia values derived from detailed thermophysical modeling. In nearly all cases the estimates agree within the error bars with the values derived from thermophysical modeling.

  16. The composition of the Eureka family of Martian Trojan asteroids

    Science.gov (United States)

    Borisov, Galin; Christou, Apostolos; Bagnulo, Stefano

    2016-10-01

    The so-called Martian Trojan asteroids orbit the Sun just inside the terrestrial planet region. They are thought to date from the earliest period of the solar system's history (Scholl et al, Icarus, 2005). Recently, Christou (Icarus, 2013) identified an orbital concentration of Trojans, named the "Eureka" cluster after its largest member, 5261 Eureka. This asteroid belongs to the rare olivine-rich A taxonomic class (Rivkin et al, Icarus, 2007; Lim et al, DPS/EPSC 2011). Unlike asteroids belonging to other taxonomies (e.g. C or S), no orbital concentrations or families of A-types are currently known to exist. These asteroids may represent samples of the building blocks that came together to form Mars and the other terrestrial planets but have since been destroyed by collisions (Sanchez et al, Icarus, 2014, and references therein).We have used the X-SHOOTER echelle spectrograph on the ESO VLT KUEYEN to obtain vis-NIR reflectance spectra of asteroids in the cluster and test their genetic relationship to Eureka. During the presentation we will show the spectra, compare them with available spectra for Eureka itself and discuss the implications for the origin of this cluster and for other olivine-dominated asteroids in the Main Belt.Based on observations made with ESO Telescopes at the La Silla-Paranal Observatory under programme ID 296.C-5030 (PI: A. Christou). Astronomical Research at Armagh Observatory is funded by the Northern Ireland Department of Culture, Arts and Leisure (DCAL).

  17. Volatile Survival on Near-Earth Asteroid 2008 EV5

    Science.gov (United States)

    Pohl, Leos; Britt, Daniel

    2016-10-01

    Asteroid 2008 EV5 is currently one of the possible targets of NASA Asteroid Redirect Mission (ARM). The objective of this mission is to recover a boulder from the surface of an asteroid. The selection of the final target requires understanding the physical characteristics of the asteroid such as the size-frequency distribution of boulders on the asteroid's surface, the presence of volatiles on the surface and below, the strength of the surface materials and the degree of their alteration. In our work, we focus on the second criterion, the possibility of volatiles presence on 2008 EV5. These can be expected to survive embedded within the crystal lattice of various phyllosilicates. The positive presence of volatiles on the surface of and inside the asteroid is important especially for ISRU hardware demonstrations. Spectral data suggest that 2008 EV5 is a member of CI chondrite group which is characterized by high phyllosilicate content (~70%) but there is also the possibility of it being a CR chondrite where the phyllosilicate content ranges significantly, from samples with negligible phyllosilicate content to samples with almost 70% phyllosilicate content. If the dynamical history of the asteroid brought it close enough to the Sun, the lattice of phyllosilicates could have disintegrated and released the volatiles (water) and the material could have dehydrated. The depth at which the dehydration might have taken place depends on the characteristic depth of heat wave penetration which in turn depends on material characteristics such as density, heat capacity and heat conductivity. These are in turn are closely linked to the porosity. The characteristic heat penetration depth also depends on orbital geometry and rotational and orbital periods. Besides the temperature itself, the dehydration is also affected by the duration of the crystal lattice breakup temperatures. We use thermal model in conjunction with available experimental data on the dehydration of clays and

  18. Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations

    Science.gov (United States)

    Pravec, Petr; Harris, Alan W.; Kušnirák, Peter; Galád, Adrián; Hornoch, Kamil

    2012-09-01

    We obtained estimates of the Johnson V absolute magnitudes (H) and slope parameters (G) for 583 main-belt and near-Earth asteroids observed at Ondřejov and Table Mountain Observatory from 1978 to 2011. Uncertainties of the absolute magnitudes in our sample are estimates reported by asteroid surveys. With our photometric H and G data, we revised the preliminary WISE albedo estimates made by Masiero et al. (Masired, J.R. et al. [2011]. Astrophys. J. 741, 68-89) and Mainzer et al. (Mainzer, A. et al. [2011b]. Astrophys. J. 743, 156-172) for asteroids in our sample. We found that the mean geometric albedo of Tholen/Bus/DeMeo C/G/B/F/P/D types with sizes of 25-300 km is pV = 0.057 with the standard deviation (dispersion) of the sample of 0.013 and the mean albedo of S/A/L types with sizes 0.6-200 km is 0.197 with the standard deviation of the sample of 0.051. The standard errors of the mean albedos are 0.002 and 0.006, respectively; systematic observational or modeling errors can predominate over the quoted formal errors. There is apparent only a small, marginally significant difference of 0.031 ± 0.011 between the mean albedos of sub-samples of large and small (divided at diameter 25 km) S/A/L asteroids, with the smaller ones having a higher albedo. The difference will have to be confirmed and explained; we speculate that it may be either a real size dependence of surface properties of S type asteroids or a small size-dependent bias in the data (e.g., a bias towards higher albedos in the optically-selected sample of asteroids). A trend of the mean of the preliminary WISE albedo estimates increasing with asteroid size decreasing from D ∼ 30 down to ∼5 km (for S types) showed in Mainzer et al. (Mainzer, A. et al. [2011a]. Astrophys. J. 741, 90-114) appears to be mainly due to the systematic bias in the MPCORB absolute magnitudes that progressively increases with H in the corresponding range H = 10-14.

  19. Rotational and translational considerations in kinetic impact deflection of potentially hazardous asteroids

    Science.gov (United States)

    Zhang, Fei; Xu, Bo; Circi, Christian; Zhang, Lei

    2017-04-01

    Kinetic impact may be the most reliable and easily implemented method to deflect hazardous asteroids using current technology. Depending on warning time, it can be effective on asteroids with diameters of a few hundred meters. Current impact deflection research often focuses on the orbital dynamics of asteroids. In this paper, we use the ejection outcome of a general oblique impact to calculate how an asteroid's rotational and translational state changes after impact. The results demonstrate how small impactors affect the dynamical state of small asteroids having a diameter of about 100 m. According to these consequences, we propose using several small impactors to hit an asteroid continuously and gently, making the deflection mission relatively flexible. After calculating the rotational variation, we find that the rotational state, especially of slender non-porous asteroids, can be changed significantly. This gives the possibility of using multiple small impactors to mitigate a potentially hazardous asteroid by spinning it up into pieces, or to despin one for future in-situ investigation (e.g., asteroid retrieval or mining).

  20. Ion Beam Shepherd for Asteroid Deflection

    CERN Document Server

    Bombardelli, C

    2011-01-01

    We present a novel concept to impart a continuous thrust to an Earth threatening asteroid from a hovering spacecraft without need for physical attachment nor gravitational interaction with the asteroid. The concept involves an ion thruster placed at a distance of a few asteroid diameters directing a stream of quasi-neutral plasma against the asteroid surface resulting into a net transferred momentum. As the transmitted force is independent of the asteroid mass and size the method allows deflecting subkilometer asteroids with a spacecraft much lighter when compared to a gravity tractor spacecraft of equal deflection capability. The finding could make low-cost asteroid deflection missions possible in the coming years.

  1. The impact of intrinsic alignment on current and future cosmic shear surveys

    CERN Document Server

    Krause, Elisabeth; Blazek, Jonathan

    2015-01-01

    Intrinsic alignment (IA) of source galaxies is one of the major astrophysical systematics for ongoing and future weak lensing surveys. This paper presents the first forecasts of the impact of IA on cosmic shear measurements for current and future surveys (DES, Euclid, LSST, WFIRST) using simulated likelihood analyses and realistic covariances that include higher-order moments of the density field in the computation. We consider a range of possible IA scenarios and test mitigation schemes, which parameterize IA by the fraction of red galaxies, normalization, luminosity and redshift dependence of the IA signal (for a subset we consider joint IA and photo-z uncertainties). Compared to previous studies we find smaller biases in time-dependent dark energy models if IA is ignored in the analysis; the amplitude and significance of these biases vary as a function of survey properties (depth, statistical uncertainties), luminosity function, and IA scenario: Due to its small statistical errors and relatively shallow ob...

  2. Design study for asteroidal exploitation

    Science.gov (United States)

    Adams, Carl; Blissit, Jim; Jarrett, Dave; Sanner, Rob; Yanagawa, Koji

    1985-08-01

    A systematic approach to asteroidal exploitation for the 1990 to 2010 time frame is presented as an initial step toward expanding the use of space beyond the space station by providing a source of lower cost materials. With only a limited amount of information known about the asteroids, reconnaissance and exploration phases to determine the exact locations and compositions of several earth-approaching asteroids are required. Earth-based telescopes are used to locate and study the asteroids, while unmanned probes will return samples of asteroidal material to earth for analysis. After these phases are completed, the retrieval of a 35,000 metric ton piece of the asteroid Anteros is undertaken. A cargo transporter uses magnetoplasmadynamic (MPD) arcjets outbound and a mass-driver using asteroidal material inbound. A crew ship uses ion engines. Low thrust trajectories are used for both spacecraft. A materials processing facility will manufacture propellant pellets and retrieve non-propellant materials for spacecraft use. The cost is 1/10th that to transport the same materials from earth to high earth orbit. The project will cost 25 percent less if done in conjunction with a lunar and Martian base.

  3. Mine Planning for Asteroid Orebodies

    Science.gov (United States)

    Gertsch, L. S.; Gertsch, R. E.

    2000-01-01

    Given that an asteroid (or comet) has been determined to contain sufficient material of value to be potentially economic to exploit, a mining method must be selected and implemented. This paper discusses the engineering necessary to bring a mine online, and the opportunities and challenges inherent in asteroid mineral prospects. The very important step of orebody characterization is discussed elsewhere. The mining methods discussed here are based on enclosing the asteroid within a bag in some fashion, whether completely or partially. In general, asteroid mining methods based on bags will consist of the following steps. Not all will be required in every case, nor necessarily in this particular sequence. Some steps will be performed simultaneously. Their purpose is to extract the valuable material from the body of the asteroid in the most efficient, cost-effective manner possible. In approximate order of initiation, if not of conclusion, the steps are: 1. Tether anchoring to the asteroid. 2. Asteroid motion control. 3. Body/fragment restraint system placement. 4. Operations platform construction. 5. Bag construction. 6. Auxiliary and support equipment placement. 7. Mining operations. 8. Processing operations. 9. Product transport to markets.

  4. Current status of health technology reassessment of non-drug technologies: survey and key informant interviews

    Directory of Open Access Journals (Sweden)

    Leggett Laura E

    2012-12-01

    Full Text Available Abstract Background Health Technology Reassessment (HTR is a structured, evidence-based assessment of the clinical, social, ethical and economic effects of a technology currently used in the health care system, to inform optimal use of that technology in comparison to its alternatives. Little is known about current international HTR practices. The objective of this research was to summarize experience-based information gathered from international experts on the development, initiation and implementation of a HTR program. Methods A mixed methods approach, using a survey and in-depth interviews, was adopted. The survey covered 8 concepts: prioritization/identification of potentially obsolete technologies; program development; implementation; mitigation; program championing; stakeholder engagement; monitoring; and reinvestment. Members of Health Technology Assessment International (HTAi and the International Network of Agencies for Health Technology Assessment (INAHTA formed the sampling frame. Participation was solicited via email and the survey was administered online using SurveyMonkey. Survey results were analyzed using descriptive statistics. To gather more in-depth knowledge, semi-structured interviews were conducted among organizations with active HTR programs. Interview questions were developed using the same 8 concepts. The hour-long interviews were recorded, transcribed and analyzed using constant comparative analysis. Results Ninety-five individuals responded to the survey: 49 were not discussing HTR, 21 were beginning to discuss HTR, nine were imminently developing a program, and 16 participants had programs and were completing reassessments. The survey results revealed that methods vary widely and that although HTR is a powerful tool, it is currently not being used to its full potential. Of the 16 with active programs, nine agreed to participate in follow-up interviews. Interview participants identified early and extensive stakeholder

  5. Survey on utility technology of a tidal and ocean current energy

    Science.gov (United States)

    Hirose, Manabu; Kadoyu, Masataka; Tanaka, Hiroyoshi

    1987-06-01

    A study is made to show the current technological levels in Japan and other nations regarding the conversion of tidal current or ocean current energy to electric power and to determine the latent energy quantities and energy-related characteristics of tidal and ocean currents. In Japan, relatively large-scale experiments made so far mostly used one of the following three types of devices: Savonius-wheel type, Darrieus-wheel type, and cross-flow-wheel type. Field experiments of tidal energy conversion have been performed at the Naruto and Kurushima Straits. The energy in the Kuroshio current is estimated at about 170 billion kWh per year. Ocean current energy does not undergo large seasonal variations. The total energy in major straits and channels in the Inland Sea and other sea areas to the west is estimated at about 124 billion kWh per year. Tidal current energy shows large seasonal variations, but it is possible to predict the changes. A survey is made to determine energy-related characteristics of a tidal current at Chichino-seto, Kagoshima Prefecture. At Chichino-seto, the flow velocity ranges from 0 to 2.2m/s, with a latent tidal current energy of about 70 kW, of which about 20 kW can actually be utilized.

  6. Current Practice Patterns Regarding the Conduct of Thyroidectomy and Parathyroidectomy amongst Surgeons - A Survey Study

    Directory of Open Access Journals (Sweden)

    LR Henry, LB Helou, NP Solomon, A Chang, SK Libutti, A Stojadinovic

    2012-01-01

    Full Text Available Background: Heterogeneity of surgical care exists among surgeons regarding the conduct of thyroidectomy and parathyroidectomy.Aim: To identify the current patterns of technical conduct of operation amongst surgeons performing thyroidectomy or parathyroidectomy.Methods: A survey was designed and beta-tested on five surgical oncologists for face validity and usability. The final version of this survey was constructed and disseminated using the professional version of the internet-based survey mechanism Survey Monkey and consisted of two eligibility questions and 22 questions regarding thyroidectomy/parathyroidectomy treatment patterns. The survey was disseminated electronically to American Association of Endocrine Surgeons (AAES and American College of Surgeons (ACS members. Survey results were collected, tabulated and analyzed. Responses among groups were compared using two sample T- tests. Significant responses were subsequently analyzed in generalized linear models to ascertain if significance remained with control of covariates.Results: Of 420 initial web survey visits, 236 (56.2% surveys were completed. The majority of respondents reported being 'fellowship trained', experienced and 'high-volume' surgeons. The most common fellowship trainings were endocrine (46%, oncology (22%, head & neck (13%, or combinations of the three fellowships (14%. Most surgeons reported that they dissect the course of the recurrent laryngeal nerve (RLN without using neuromonitoring. Nearly a third of respondents reported routinely using the Harmonic scalpel during the conduct of the operations. Significant differences emerged regarding operative technique according to residency training type, fellowship training, surgeon volume, and practice setting, but only those associated with residency training type and annual surgeon surgical volume remained significant within generalized linear models.Conclusion: Most surgeons who responded to this survey do not routinely

  7. Double Asteroid Redirection Test (DART)

    Science.gov (United States)

    Cheng, A. F.

    2016-12-01

    The Asteroid Impact Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the NASA Double Asteroid Redirection Test (DART) kinetic impactor mission and the ESA Asteroid Impact Mission (AIM) which is the rendezvous spacecraft. The AIDA target is the near-Earth binary asteroid 65803 Didymos. During the Didymos close approach to Earth in October, 2022, the DART spacecraft will impact the Didymos secondary at 6 km/s and deflect its trajectory, changing the orbital period of the binary. This change can be measured by Earth-based optical and radar observations. The primary goals of AIDA are to (1) perform a full-scale demonstration of asteroid deflection by kinetic impact; (2) measure the resulting deflection; and (3) validate and improve models for momentum transfer in high-speed impacts on an asteroid. The combined DART and AIM missions will provide the first measurements of momentum transfer efficiency from a kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are also characterized. In addition to a measurable change in the binary orbit period, the DART kinetic impact is predicted to induce forced librations of the Didymos secondary of up to several degrees amplitude. It will furthermore make a crater that will be studied in detail by the AIM spacecraft, and it will release a volume of particulate ejecta that may be directly observable from Earth or even resolvable as a coma or an ejecta tail by ground-based telescopes. Updates will be given on DART status and study results.

  8. Quality metrics currently used in academic radiology departments: results of the QUALMET survey.

    Science.gov (United States)

    Walker, Eric A; Petscavage-Thomas, Jonelle M; Fotos, Joseph S; Bruno, Michael A

    2017-03-01

    We present the results of the 2015 quality metrics (QUALMET) survey, which was designed to assess the commonalities and variability of selected quality and productivity metrics currently employed by a large sample of academic radiology departments representing all regions in the USA. The survey of key radiology metrics was distributed in March-April of 2015 via personal e-mail to 112 academic radiology departments. There was a 34.8% institutional response rate. We found that most academic departments of radiology commonly utilize metrics of hand hygiene, report turn around time (RTAT), relative value unit (RVU) productivity, patient satisfaction and participation in peer review. RTAT targets were found to vary widely. The implementation of radiology peer review and the variety of ways in which peer review results are used within academic radiology departments, the use of clinical decision support tools and requirements for radiologist participation in Maintenance of Certification also varied. Policies for hand hygiene and critical results communication were very similar across all institutions reporting, and most departments utilized some form of missed case/difficult case conference as part of their quality and safety programme, as well as some form of periodic radiologist performance reviews. Results of the QUALMET survey suggest many similarities in tracking and utilization of the selected quality and productivity metrics included in our survey. Use of quality indicators is not a fully standardized process among academic radiology departments. Advances in knowledge: This article examines the current quality and productivity metrics in academic radiology.

  9. Mass Casualty Decontamination in the United States: An Online Survey of Current Practice.

    Science.gov (United States)

    Power, Sarah; Symons, Charles; Carter, Holly; Jones, Emma; Amlôt, Richard; Larner, Joanne; Matar, Hazem; Chilcott, Robert P

    2016-01-01

    Mass casualty decontamination is a public health intervention that would be employed by emergency responders following a chemical, biological, or radiological incident. The decontamination of large numbers of casualties is currently most often performed with water to remove contaminants from the skin surface. An online survey was conducted to explore US fire departments' decontamination practices and their preparedness for responding to incidents involving mass casualty decontamination. Survey respondents were asked to provide details of various aspects of their decontamination procedures, including expected response times to reach casualties, disrobing procedures, approaches to decontamination, characteristics of the decontamination showering process, provision for special populations, and any actions taken following decontamination. The aim of the survey was to identify any differences in the way in which decontamination guidance is implemented across US states. Results revealed that, in line with current guidance, many US fire departments routinely use the "ladder-pipe system" for conducting rapid, gross decontamination of casualties. The survey revealed significant variability in ladder-pipe construction, such as the position and number of fire hoses used. There was also variability in decontamination characteristics, such as water temperature and water pressure, detergent use, and shower duration. The results presented here provide important insights into the ways in which implementation of decontamination guidance can vary between US states. These inconsistencies are thought to reflect established perceived best practices and local adaptation of response plans to address practical and logistical constraints. These outcomes highlight the need for evidence-based national guidelines for conducting mass casualty decontamination.

  10. Global Catastrophes in Perspective: Asteroid Impacts vs Climate Change

    Science.gov (United States)

    Boslough, M. B.; Harris, A. W.

    2008-12-01

    When allocating resources to address threats, decision makers are best served by having objective assessments of the relative magnitude of the threats in question. Asteroids greater than about 1 km in diameter are assumed by the planetary impact community to exceed a "global catastrophe threshold". Impacts from smaller objects are expected to cause local or regional destruction, and would be the proximate cause of most associated fatalities. Impacts above the threshold would be expected to alter the climate, killing billions of people and causing a collapse of civilization. In this apocalyptic scenario, only a small fraction of the casualties would be attributable to direct effects of the impact: the blast wave, thermal radiation, debris, ground motion, or tsunami. The vast majority of deaths would come later and be due to indirect causes: starvation, disease, or violence as a consequence of societal disruption related to the impact-induced global climate change. The concept of a catastrophe threshold comes from "nuclear winter" studies, which form the basis for quantitative estimates of the consequences of a large impact. The probability estimates come from astronomical observations and statistical analysis. Much of the impact threat, at its core, is a climate-change threat. Prior to the Spaceguard Survey of Near-Earth Objects (NEOs), the chance of dying from an asteroid impact was estimated to be 1 in 25,000 (Chapman & Morrison, 1994). Most of the large asteroids have now been discovered, and none is on an impact trajectory. Moreover, new data show that mid-sized asteroids (tens to hundreds of meters across) are less abundant than previously thought, by a factor of three. We now estimate that the lifetime odds of being killed by the impact of one of the remaining undiscovered NEOs are about one in 720,000 for individuals with a life expectancy of 80 years (Harris, 2008). One objective way to compare the relative magnitude of the impact threat to that of

  11. The Cratering History of Asteroid (2867) Steins

    CERN Document Server

    Marchi, S; Kueppers, M; Marzari, F; Davidsson, B; Keller, H U; Besse, S; Lamy, P; Mottola, S; Massironi, M; Cremonese, G

    2010-01-01

    The cratering history of main belt asteroid (2867) Steins has been investigated using OSIRIS imagery acquired during the Rosetta flyby that took place on the 5th of September 2008. For this purpose, we applied current models describing the formation and evolution of main belt asteroids, that provide the rate and velocity distributions of impactors. These models coupled with appropriate crater scaling laws, allow the cratering history to be estimated. Hence, we derive Steins' cratering retention age, namely the time lapsed since its formation or global surface reset. We also investigate the influence of various factors -like bulk structure and crater erasing- on the estimated age, which spans from a few hundred Myrs to more than 1Gyr, depending on the adopted scaling law and asteroid physical parameters. Moreover, a marked lack of craters smaller than about 0.6km has been found and interpreted as a result of a peculiar evolution of Steins cratering record, possibly related either to the formation of the 2.1km ...

  12. Images of an Activated Asteroid

    Science.gov (United States)

    Kohler, Susanna

    2016-08-01

    In late April of this year, asteroid P/2016 G1 (PANSTARRS) was discovered streaking through space, a tail of dust extending behind it. What caused this asteroids dust activity?Asteroid or Comet?Images of asteroid P/2016 G1 at three different times: late April, late May, and mid June. The arrow in the center panel points out an asymmetric feature that can be explained if the asteroid initially ejected material in a single direction, perhaps due to an impact. [Moreno et al. 2016]Asteroid P/2016 G1 is an interesting case: though it has the orbital elements of a main-belt asteroid it orbits at just under three times the EarthSun distance, with an eccentricity of e ~ 0.21 its appearance is closer to that of a comet, with a dust tail extending 20 behind it.To better understand the nature and cause of this unusual asteroids activity, a team led by Fernando Moreno (Institute of Astrophysics of Andalusia, in Spain) performed deep observations of P/2016 G1 shortly after its discovery. The team used the 10.4-meter Great Canary Telescope to image the asteroid over the span of roughly a month and a half.A Closer Look at P/2016 G1P/2016 G1 lies in the inner region of the main asteroid belt, so it is unlikely to have any ices that suddenly sublimated, causing the outburst. Instead, Moreno and collaborators suggest that the asteroids tail may have been caused by an impact that disrupted the parent body.To test this idea, the team used computer simulations to model their observations of P/2016 G1s dust tail. Based on their models, they demonstrate that the asteroid was likely activated on February 10 2016 roughly 350 days before it reached perihelion in its orbit and its activity was a short-duration event, lasting only ~24 days. The teams models indicate that over these 24 days, the asteroid lost around 20 million kilograms of dust, and at its maximum activity level, it was ejecting around 8 kg/s!Comparison of the observation from late May (panel a) and two models: one in which

  13. Improved Asteroid Astrometry and Photometry with Trail Fitting

    CERN Document Server

    Vereš, Peter; Denneau, Larry; Wainscoat, Richard; Holman, Matthew J; Lin, Hsing-Wen

    2012-01-01

    Asteroid detections in astronomical images may appear as trails due to a combination of their apparent rate of motion and exposure duration. Nearby asteroids in particular typically have high apparent rates of motion and acceleration. Their recovery, especially on their discovery apparition, depends upon obtaining good astrometry from the trailed detections. We present an analytic function describing a trailed detection under the assumption of a Gaussian point spread function (PSF) and constant rate of motion. We have fit the function to both synthetic and real trailed asteroid detections from the Pan-STARRS1 survey telescope to obtain accurate astrometry and photometry. For short trails our trailing function yields the same astrometric and photometry accuracy as a functionally simpler 2-d Gaussian but the latter underestimates the length of the trail - a parameter that can be important for measuring the object's rate of motion and assessing its cometary activity. For trails longer than about 10 pixels (> 3xP...

  14. NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos

    CERN Document Server

    Nugent, C R; Bauer, J; Cutri, R M; Kramer, E A; Grav, T; Masiero, J; Sonnett, S; Wright, E L

    2016-01-01

    The Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) mission continues to detect, track, and characterize minor planets. We present diameters and albedos calculated from observations taken during the second year since the spacecraft was reactivated in late 2013. These include 207 near-Earth asteroids and 8,885 other asteroids. $84\\%$ of the near-Earth asteroids did not have previously measured diameters and albedos by the NEOWISE mission. Comparison of sizes and albedos calculated from NEOWISE measurements with those measured by occultations, spacecraft, and radar-derived shapes shows accuracy consistent with previous NEOWISE publications. Diameters and albedos fall within $ \\pm \\sim20\\%$ and $\\pm\\sim40\\%$, 1-sigma, respectively, of those measured by these alternate techniques. NEOWISE continues to preferentially discover near-Earth objects which are large ($>100$ m), and have low albedos.

  15. Near-Earth Asteroids as Possible Parent Bodies of Meteor Streams

    Directory of Open Access Journals (Sweden)

    M.G. Sokolova

    2016-12-01

    Full Text Available The genetic relationship of meteor streams with near-Earth asteroids (NEAs is being actively studied. A genetic link with the asteroid is possible only for streams in which meteoroids have the geocentric speed smaller than 50 km/s, thereby meaning the proportionality of their orbits with the orbits of asteroids. To date, there are about 40 such orphan streams with unknown parent bodies. In the paper, NEA groups (Aten, Apollo, Amor, and Atira have been considered from the perspective of possible search for the parent bodies of meteor streams among them. The groups have been compared based on the following parameters: eccentricity of asteroid orbits, as well as size and chemical composition of asteroids. Currently, it is considered that the surface of asteroids with elongated orbits is subjected to temperature fall: it is heated in perihelion and cooled in aphelion. Due to small orbital periods around the Sun (about 2–4 years, this may lead to formation of meteoroid clusters. Therefore, comparison of asteroids by their orbit shape and physicochemical parameters enables us to distinguish between NEA groups of asteroids and the Apollo group as most probable candidates to search for the parent bodies of meteor streams among NEAs. Unfortunately, finding physicochemical parameters poses great difficulties, since they are only detectable for some asteroids. At the same time, it is impossible to study asteroids dynamics, evolution, and relation with other bodies of the Solar system, as well as to realistically assess the impact of NEAs and products of their disintegration collision with the Earth and to develop systems of anti-asteroid protection without knowing the following parameters of asteroids: mineralogical composition, density, size, and accurate mass.

  16. The current state of physical therapy pain curricula in the United States: a faculty survey.

    Science.gov (United States)

    Hoeger Bement, Marie K; Sluka, Kathleen A

    2015-02-01

    Insufficient pain education is problematic across the health care spectrum. Recent educational advancements have been made to combat the deficits in pain education to ensure that health care professionals are proficient in assessing and managing pain. The purpose of this survey was to determine the extent of pain education in current Doctorate of Physical Therapy schools in the United States, including how pain is incorporated into the curriculum, the amount of time spent teaching about pain, and the resources used to teach about pain. The survey consisted of 10 questions in the following subject areas: basic science mechanisms and concepts about pain, pain assessment, pain management, and adequacy of pain curriculum. The overall response was 77% (167/216) for the first series of responses of the survey (Question 1), whereas 62% completed the entire survey (Questions 2-10). The average contact hours teaching about pain was 31 ± 1.8 (mean ± standard error of the mean) with a range of 5 to 115 hours. The majority of schools that responded covered the science of pain, assessment, and management. Less than 50% of respondents were aware of the Institute of Medicine report on pain or the International Association for the Study of Pain guidelines for physical therapy pain education. Only 61% of respondents believed that their students received adequate education in pain management. Thus, this survey demonstrated how pain education is incorporated into physical therapy schools and highlighted areas for improvement such as awareness of recent educational advancements. This article demonstrates how pain education is incorporated into physical therapy curricula within accredited programs. Understanding the current structure of pain education in health professional curriculum can serve as a basis to determine if recent publications of guidelines and competencies impact education. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

  17. Challenges in pancreatic adenocarcinoma surgery - National survey and current practice guidelines

    Science.gov (United States)

    Dhayat, Sameer A.; Mirgorod, Philip; Lenschow, Christina; Senninger, Norbert

    2017-01-01

    Background Pancreatic ductal adenocarcinoma (PDAC) remains one of the most deadly cancers in Europe and the USA. There is consensus that radical tumor surgery is the only viable option for any long-term survival in patients with PDAC. So far, limited data are available regarding the routine surgical management of patients with advanced PDAC in the light of surgical guidelines. Methods A national survey on perioperative management of patients with PDAC and currently applied criteria on their tumor resectability in German university and community hospitals was carried out. Results With a response rate of 81.6% (231/283) a total of 95 (41.1%) participating departments practicing pancreatic surgery in Germany are certified as competence and reference centers for surgical diseases of the pancreas in 2016. More than 95% of them indicate to carry out structured and interdisciplinary therapies along with an interdisciplinary pre- and postoperative tumor board. The majority of survey respondents prefer the pylorus-preserving partial pancreatoduodenectomy (93.1%) with standard lymphadenectomy for cancer of the pancreatic head. Intraoperative histological evaluation of the resection margins is used regularly by 99% of the survey respondents. 98.7% of survey respondents carry out partial or complete vein resection, 126 respondents (54.5%) would resect tumor adjacent arteries, and 102 respondents (44.2%) would perform metastasectomy if complete PDAC resection (R0) is possible. Conclusion Evidence-based and standardized pancreatic surgery is practiced by a large number of hospitals in Germany. However, a significant number of survey respondents support an extended radical tumor resection in patients with advanced PDAC even when not indicated by current clinical guidelines. PMID:28267771

  18. Near Earth Asteroid Scout Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In considering targets for human asteroid missions, there are several major factors that will make a significant difference in assessment of mission risks that...

  19. Solar wind tans young asteroids

    Science.gov (United States)

    2009-04-01

    A new study published in Nature this week reveals that asteroid surfaces age and redden much faster than previously thought -- in less than a million years, the blink of an eye for an asteroid. This study has finally confirmed that the solar wind is the most likely cause of very rapid space weathering in asteroids. This fundamental result will help astronomers relate the appearance of an asteroid to its actual history and identify any after effects of a catastrophic impact with another asteroid. ESO PR Photo 16a/09 Young Asteroids Look Old "Asteroids seem to get a ‘sun tan' very quickly," says lead author Pierre Vernazza. "But not, as for people, from an overdose of the Sun's ultraviolet radiation, but from the effects of its powerful wind." It has long been known that asteroid surfaces alter in appearance with time -- the observed asteroids are much redder than the interior of meteorites found on Earth [1] -- but the actual processes of this "space weathering" and the timescales involved were controversial. Thanks to observations of different families of asteroids [2] using ESO's New Technology Telescope at La Silla and the Very Large Telescope at Paranal, as well as telescopes in Spain and Hawaii, Vernazza's team have now solved the puzzle. When two asteroids collide, they create a family of fragments with "fresh" surfaces. The astronomers found that these newly exposed surfaces are quickly altered and change colour in less than a million years -- a very short time compared to the age of the Solar System. "The charged, fast moving particles in the solar wind damage the asteroid's surface at an amazing rate [3]", says Vernazza. Unlike human skin, which is damaged and aged by repeated overexposure to sunlight, it is, perhaps rather surprisingly, the first moments of exposure (on the timescale considered) -- the first million years -- that causes most of the aging in asteroids. By studying different families of asteroids, the team has also shown that an asteroid

  20. Asteroid named after CAS scientist

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ An asteroid has been named after CAS astronomy historian XI Zezong with the approval of the International Minor Planet Nomenclature Committee (IMPNC), announced China's National Astronomical Observatories at CAS (NAOC) on 17 August.

  1. A search for fast optical transients in the Pan-STARRS1 medium-deep survey: M-dwarf flares, asteroids, limits on extragalactic rates, and implications for LSST

    Energy Technology Data Exchange (ETDEWEB)

    Berger, E.; Leibler, C. N.; Chornock, R.; Foley, R. J.; Soderberg, A. M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Price, P. A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Burgett, W. S.; Chambers, K. C.; Flewelling, H.; Huber, M. E.; Magnier, E. A.; Tonry, J. L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Metcalfe, N. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Stubbs, C. W. [Department of Physics, Harvard University, Cambridge, MA 02138 (United States)

    2013-12-10

    We present a search for fast optical transients (τ ∼ 0.5 hr-1 day) using repeated observations of the Pan-STARRS1 Medium-Deep Survey (PS1/MDS) fields. Our search takes advantage of the consecutive g {sub P1} r {sub P1} observations (16.5 minutes in each filter), by requiring detections in both bands, with non-detections on preceding and subsequent nights. We identify 19 transients brighter than 22.5 AB mag (S/N ≳ 10). Of these, 11 events exhibit quiescent counterparts in the deep PS1/MDS templates that we identify as M4-M9 dwarfs at d ≈ 0.2-1.2 kpc. The remaining eight transients lack quiescent counterparts, exhibit mild but significant astrometric shifts between the g {sub P1} and r {sub P1} images, colors of (g – r){sub P1} ≈ 0.5-0.8 mag, non-varying light curves, and locations near the ecliptic plane with solar elongations of about 130°, which are all indicative of main-belt asteroids near the stationary point of their orbits. With identifications for all 19 transients, we place an upper limit of R {sub FOT}(τ ∼ 0.5 hr) ≲ 0.12 deg{sup –2} day{sup –1} (95% confidence level) on the sky-projected rate of extragalactic fast transients at ≲ 22.5 mag, a factor of 30-50 times lower than previous limits; the limit for a timescale of ∼1 day is R {sub FOT} ≲ 2.4 × 10{sup –3} deg{sup –2} day{sup –1}. To convert these sky-projected rates to volumetric rates, we explore the expected peak luminosities of fast optical transients powered by various mechanisms, and find that non-relativistic events are limited to M ≈ –10 to ≈ – 14 mag for a timescale of ∼0.5 hr to ∼1 day, while relativistic sources (e.g., gamma-ray bursts, magnetar-powered transients) can reach much larger luminosities. The resulting volumetric rates are ≲ 13 Mpc{sup –3} yr{sup –1} (M ≈ –10 mag), ≲ 0.05 Mpc{sup –3} yr{sup –1} (M ≈ –14 mag), and ≲ 10{sup –6} Mpc{sup –3} yr{sup –1} (M ≈ –24 mag), significantly above the nova, supernova

  2. Solar Radiation and Asteroidal Motion

    CERN Document Server

    Klacka, J

    2000-01-01

    Effects of solar wind and solar electromagnetic radiation on motion of asteroids are discussed. The results complete the statements presented in Vokrouhlick\\'{y} and Milani (2000). As for the effect of electromagnetic radiation, the complete equation of motion is presented to the first order in $v/c$ -- the shape of asteroid (spherical body is explicitly presented) and surface distribution of albedo should be taken into account. Optical quantities must be calculated in proper frame of reference.

  3. The Main Asteroid Belt: The Crossroads of the Solar System

    Science.gov (United States)

    Michel, Patrick

    2015-08-01

    Orbiting the Sun between Mars and Jupiter, main belt asteroids are leftover planetary building blocks that never accreted enough material to become planets. They are therefore keys to understanding how the Solar System formed and evolved. They may also provide clues to the origin of life, as similar bodies may have delivered organics and water to the early Earth.Strong associations between asteroids and meteorites emerged thanks to multi-technique observations, modeling, in situ and sample return analyses. Spacecraft images revolutionized our knowledge of these small worlds. Asteroids are stunning in their diversity in terms of physical properties. Their gravity varies by more orders of magnitude than its variation among the terrestrial planets, including the Moon. Each rendezvous with an asteroid thus turned our geological understanding on its head as each asteroid is affected in different ways by a variety of processes such as landslides, faulting, and impact cratering. Composition also varies, from ice-rich to lunar-like to chondritic.Nearly every asteroid we see today, whether of primitive or evolved compositions, is the product of a complex history involving accretion and one or more episodes of catastrophic disruption that sometimes resulted in families of smaller asteroids that have distinct and indicative petrogenic relationships. These families provide the best data to study the impact disruption process at scales far larger than those accessible in laboratory. Tens, perhaps hundreds, of early asteroids grew large enough to thermally differentiate. Their traces are scattered pieces of their metal-rich cores and, more rarely, their mantles and crusts.Asteroids represent stages on the rocky road to planet formation. They have great stories to tell about the formation and evolution of our Solar System as well as other planetary systems: asteroid belts seem common around Sun-like stars. We will review our current knowledge on their properties, their link to

  4. Rip current evidence by hydrodynamic simulations, bathymetric surveys and UAV observation

    Science.gov (United States)

    Benassai, Guido; Aucelli, Pietro; Budillon, Giorgio; De Stefano, Massimo; Di Luccio, Diana; Di Paola, Gianluigi; Montella, Raffaele; Mucerino, Luigi; Sica, Mario; Pennetta, Micla

    2017-09-01

    The prediction of the formation, spacing and location of rip currents is a scientific challenge that can be achieved by means of different complementary methods. In this paper the analysis of numerical and experimental data, including RPAS (remotely piloted aircraft systems) observations, allowed us to detect the presence of rip currents and rip channels at the mouth of Sele River, in the Gulf of Salerno, southern Italy. The dataset used to analyze these phenomena consisted of two different bathymetric surveys, a detailed sediment analysis and a set of high-resolution wave numerical simulations, completed with Google EarthTM images and RPAS observations. The grain size trend analysis and the numerical simulations allowed us to identify the rip current occurrence, forced by topographically constrained channels incised on the seabed, which were compared with observations.

  5. Acellular Dermal Matrix in Reconstructive Breast Surgery: Survey of Current Practice among Plastic Surgeons

    Science.gov (United States)

    Ibrahim, Ahmed M. S.; Koolen, Pieter G. L.; Ashraf, Azra A.; Kim, Kuylhee; Mureau, Marc A. M.; Lee, Bernard T.

    2015-01-01

    Background: Acellular dermal matrices (ADMs) in plastic surgery have become increasingly popular particularly for breast reconstruction. Despite their advantages, questions exist regarding their association with a possible increased incidence of complications. We describe a collective experience of plastic surgeons’ use of ADMs in reconstructive breast surgery using an internet-based survey. Methods: Members of the American Society of Plastic Surgeons were recruited through voluntary, anonymous participation in an online survey. The web-based survey garnered information about participant demographics and their experience with ADM use in breast reconstruction procedures. After responses were collected, all data were anonymously processed. Results: Data were ascertained through 365 physician responses of which 99% (n = 361) completed the survey. The majority of participants were men (84.5%) between 51 and 60 years (37.4%); 84.2% used ADM in breast reconstruction, including radiated patients (79.7%). ADM use was not favored for nipple reconstruction (81.5%); 94.6% of participants used drains, and 87.8% administered antibiotics postoperatively. The most common complications were seroma (70.9%) and infection (16%), although 57.4% claimed anecdotally that overall complication rate was unchanged after incorporating ADM into their practice. High cost was a deterrent for ADM use (37.5%). Conclusions: Plastic surgeons currently use ADM in breast reconstruction for both immediate and staged procedures. Of those responding, a majority of plastic surgeons will incorporate drains and use postoperative antibiotics for more than 48 hours. PMID:25973359

  6. Repeated surveys by acoustic Doppler current profiler for flow and sediment dynamics in a tidal river

    Science.gov (United States)

    Dinehart, R. L.; Burau, J. R.

    2005-11-01

    A strategy of repeated surveys by acoustic Doppler current profiler (ADCP) was applied in a tidal river to map velocity vectors and suspended-sediment indicators. The Sacramento River at the junction with the Delta Cross Channel at Walnut Grove, California, was surveyed over several tidal cycles in the Fall of 2000 and 2001 with a vessel-mounted ADCP. Velocity profiles were recorded along flow-defining survey paths, with surveys repeated every 27 min through a diurnal tidal cycle. Velocity vectors along each survey path were interpolated to a three-dimensional Cartesian grid that conformed to local bathymetry. A separate array of vectors was interpolated onto a grid from each survey. By displaying interpolated vector grids sequentially with computer animation, flow dynamics of the reach could be studied in three-dimensions as flow responded to the tidal cycle. Velocity streamtraces in the grid showed the upwelling of flow from the bottom of the Sacramento River channel into the Delta Cross Channel. The sequential display of vector grids showed that water in the canal briefly returned into the Sacramento River after peak flood tides, which had not been known previously. In addition to velocity vectors, ADCP data were processed to derive channel bathymetry and a spatial indicator for suspended-sediment concentration. Individual beam distances to bed, recorded by the ADCP, were transformed to yield bathymetry accurate enough to resolve small bedforms within the study reach. While recording velocity, ADCPs also record the intensity of acoustic backscatter from particles suspended in the flow. Sequential surveys of backscatter intensity were interpolated to grids and animated to indicate the spatial movement of suspended sediment through the study reach. Calculation of backscatter flux through cross-sectional grids provided a first step for computation of suspended-sediment discharge, the second step being a calibrated relation between backscatter intensity and sediment

  7. VizieR Online Data Catalog: Properties of asteroids in comet-like orbits (Kim+, 2014)

    Science.gov (United States)

    Kim, Y.; Ishiguro, M.; Usui, F.

    2017-03-01

    We used infrared asteroid databases compiled from three infrared all-sky surveyors, the IRAS (Neugebauer et al. 1984ApJ...278L..83N), AKARI (Murakami et al. 2007PASJ...59S.369M), and the Wide-field Infrared Survey Explorer (WISE; Wright et al. 2010AJ....140.1868W). Usui et al. (2014, J/PASJ/63/1117) compared these three infrared asteroid catalogs with valid sizes and albedos and merged them into a single catalog (I-A-W). They archived 138,285 asteroids with sizes and albedos, detected with either IRAS, AKARI, or WISE in I-A-W. A number of asteroids were detected by two or three satellites: 1993 asteroids by all three satellites, 2812 asteroids by AKARI and WISE, and 312 asteroids by IRAS and WISE. In such cases, Usui et al. (2014, J/PASJ/63/1117) selected data from AKARI as the highest priority, WISE as the second, and IRAS as the third priority, although there are no remarkable differences in the sizes and albedos among these catalogs. AKARI data were given highest priority because its data have less uncertainty than WISE in the sizes and albedos for the largest asteroids. We used the I-A-W catalog in the analysis of ACOs. (1 data file).

  8. Near-infrared spectra of high-albedo outer main-belt asteroids

    Energy Technology Data Exchange (ETDEWEB)

    Kasuga, Toshihiro; Shirahata, Mai [National Institutes of Natural Science, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 (Japan); Usui, Fumihiko [Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kuroda, Daisuke [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, 3037-5 Honjo, Kamogata-cho, Asakuchi, Okayama 719-0232 (Japan); Ootsubo, Takafumi [Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902 (Japan); Okamura, Natsuko [Department of Complexity Science and Engineering, The University of Tokyo Kiban Bldg. 408, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Hasegawa, Sunao, E-mail: toshi.kasuga@nao.ac.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 252-5210 (Japan)

    2015-02-01

    Most outer main-belt asteroids have low albedos because of their carbonaceouslike bodies. However, infrared satellite surveys have revealed that some asteroids have high albedos, which may suggest the presence of unusual surface minerals for those primitive objects. We present new near-infrared (1.1–2.5 μm) spectra of four outer main-belt asteroids with albedos ≥ 0.1. The C-complex asteroids (555) Norma and (2542) Calpurnia are featureless and have (50%–60%) amorphous Mg pyroxenes that might explain the high albedos. Asteroids (701) Oriola (which is a C-complex asteroid) and (2670) Chuvashia (a D/T-type or M-type asteroid) show possible broad absorption bands (1.5–2.1 μm). The feature can be reproduced by either Mg-rich amorphous pyroxene (with 50%–60% and 80%–95% Mg, respectively) or orthopyroxene (crystalline silicate), which might be responsible for the high albedos. No absorption features of water ice (near 1.5 and 2.0 μm) are detected in the objects. We discuss the origin of high albedo components in the outer main-belt asteroids and their physical relations to comets.

  9. Tracing High Redshift Starformation in the Current and Next Generation of Radio Surveys

    CERN Document Server

    Seymour, Nick

    2009-01-01

    The current deepest radio surveys detect hundreds of sources per square degree below 0.1mJy. There is a growing consensus that a large fraction of these sources are dominated by star formation although the exact proportion has been debated in the literature. However, the low luminosity of these galaxies at most other wavelengths makes determining the nature of individual sources difficult. If future, deeper surveys performed with the next generation of radio instrumentation are to reap high scientific reward we need to develop reliable methods of distinguishing between radio emission powered by active galactic nuclei (AGN) and that powered by star formation. In particular, we believe that such discriminations should be based on purely radio, or relative to radio, diagnostics. These diagnostics include radio morphology, radio spectral index, polarisation, variability, radio luminosity and flux density ratios with non-radio wavelengths e.g. with different parts of the infrared (IR) regime. We discuss the advant...

  10. Disability Items From the Current Population Survey (2008-2015) and Permanent Versus Temporary Disability Status.

    Science.gov (United States)

    Ward, Bryce; Myers, Andrew; Wong, Jennifer; Ravesloot, Craig

    2017-05-01

    To examine longitudinal responses to the disability indicator questions that have been adopted as the standard across national surveys sponsored by the US Department of Health and Human Services. Data from the Current Population Survey between 2008 and 2015 were linked to create a longitudinal sample of 721 178 individual respondents. Responses to the disability questions fluctuated significantly. Although 17% of all respondents reported a disability at some point, only 3% consistently reported the same set of disabilities. Demographic differences were found between people who always reported a consistent set of disabilities and those whose responses fluctuated. The disability questions capture 2 discrete groups: people who experience a permanent disability and those who experience a temporary disability. Demographic differences between these groups suggest that this is not simply due to measurement error.

  11. Hayabusa2 mission target asteroid (162173) 1999 JU_3: Searching for the object's spin-axis orientation

    NARCIS (Netherlands)

    Müller, T.; Durech, J.; Mueller, M.; Kiss, C.; Vilenius, E.; Ishiguro, M.

    2014-01-01

    The JAXA Hayabusa2 mission was approved in 2011 with launch planned for late 2014. Arriving at the asteroid (162173) 1999 JU_3 in 2018, it will survey it, land, and obtain surface material, then depart in late 2019, and return to the Earth in December 2020. We observed the near-Earth asteroid 1999 J

  12. Hayabusa2 mission target asteroid (162173) 1999 JU_3: Searching for the object's spin-axis orientation

    NARCIS (Netherlands)

    Müller, T.; Durech, J.; Mueller, M.; Kiss, C.; Vilenius, E.; Ishiguro, M.

    2014-01-01

    The JAXA Hayabusa2 mission was approved in 2011 with launch planned for late 2014. Arriving at the asteroid (162173) 1999 JU_3 in 2018, it will survey it, land, and obtain surface material, then depart in late 2019, and return to the Earth in December 2020. We observed the near-Earth asteroid 1999

  13. Cancer pain management in China: current status and practice implications based on the ACHEON survey.

    Science.gov (United States)

    Xia, Zhongjun

    2017-01-01

    Cancer pain can seriously impact the quality of life (QoL) of patients, and optimal management practices are therefore of paramount importance. The ACHEON survey queried physicians and patients from 10 Asian countries/regions to assess current clinical practices in cancer pain management in Asia. This study presents the data obtained for cancer pain management in mainland China, with an emphasis on practices related to opioid drugs. In several tertiary hospitals across China, 250 patients experiencing cancer pain and 100 physicians were surveyed on questions designed to assess current cancer pain management practices and cancer pain impact on QoL. The patient survey showed that 88% of patients reported moderate-to-severe cancer pain, with a median duration of 6 months. The physician survey showed that medical school/residency training with regard to cancer pain management was inadequate in ~80% of physicians. A total of 80% of physicians and 67.2% of patients reported that pain scale was used during pain assessment; 84% of physicians expressed that physician-perceived pain severity was not completely consistent with actual pain the patient experienced. Of the 147 patients who recalled the medication received, 83.7% were administered opioid prescriptions. Of the 240 patients who received treatment, 43.8% perceived the inadequacy of controlling pain. The primary barriers from physicians perceived to optimal pain management included patients' fear of side effects (58%), patients' fear of addiction (53%), patients' reluctance to report pain (43%), physicians' reluctance to prescribe (29%), physicians' inadequacy of pain assessment (27%) and excessive regulation of opioid analgesics (47%). Knowledge of cancer pain management should be strengthened among physicians. Quantitative pain assessment and principle-based pain management should be combined to achieve pain relief. Misconceptions about opioids in patients and physicians and poor report about pain should be

  14. Refining the asteroid taxonomy by polarimetric observations

    Science.gov (United States)

    Belskaya, I. N.; Fornasier, S.; Tozzi, G. P.; Gil-Hutton, R.; Cellino, A.; Antonyuk, K.; Krugly, Yu. N.; Dovgopol, A. N.; Faggi, S.

    2017-03-01

    We present new results of polarimetric observations of 15 main belt asteroids of different composition. By merging new and published data we determined polarimetric parameters characterizing individual asteroids and mean values of the same parameters characterizing different taxonomic classes. The majority of asteroids show polarimetric phase curves close to the average curve of the corresponding class. We show that using polarimetric data it is possible to refine asteroid taxonomy and derive a polarimetric classification for 283 main belt asteroids. Polarimetric observations of asteroid (21) Lutetia are found to exhibit possible variations of the position angle of the polarization plane over the surface.

  15. Dynamical erosion of the asteroid belt and implications for large impacts in the inner solar system

    CERN Document Server

    Minton, David A

    2009-01-01

    The cumulative effects of weak resonant and secular perturbations by the major planets produce chaotic behavior of asteroids on long timescales. Dynamical chaos is the dominant loss mechanism for asteroids with diameters D > 10 km in the current asteroid belt. In a numerical analysis of the long term evolution of test particles in the main asteroid belt region, we find that the dynamical loss history of test particles from this region is well described with a logarithmic decay law. In our simulations the loss rate function that is established at t = 1 My persists with little deviation to at least t = 4 Gy. Our study indicates that the asteroid belt region has experienced a significant amount of depletion due to this dynamical erosion - having lost as much as ~50% of the large asteroids - since 1 My after the establishment of the current dynamical structure of the asteroid belt. Because the dynamical depletion of asteroids from the main belt is approximately logarithmic, an equal amount of depletion occurred i...

  16. The Double Asteroid Redirection Test in the AIDA Project

    Science.gov (United States)

    Cheng, Andrew; Rivkin, Andrew; Michel, Patrick

    2016-04-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, that includes the ESA Asteroid Impact Mission (AIM) rendezvous mission and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The ~300-kg DART spacecraft is designed to impact the Didymos secondary at 7 km/s and demonstrate the ability to modify its trajectory through momentum transfer. DART and AIM are currently Phase A studies supported by NASA and ESA respectively. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid, by targeting an object larger than ~100 m and large enough to qualify as a Potentially Hazardous Asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the period change of the binary orbit; (3) understand the hyper-velocity collision effects on an asteroid, including the long-term dynamics of impact ejecta; and validate models for momentum transfer in asteroid impacts, based on measured physical properties of the asteroid surface and sub-surface. The primary DART objectives are to demonstrate a hyper-velocity impact on the Didymos moon and to determine the resulting deflection from ground-based observatories. The DART impact on the Didymos secondary will cause a measurable change in the orbital period of the binary. Supporting Earth-based optical and radar observations and numerical simulation studies are an integral part of the DART mission. The baseline DART mission launches in December, 2020 to impact the Didymos secondary in September, 2022. There are multiple launch opportunities for DART leading to impact around the 2022 Didymos close

  17. The Distribution of Basaltic Asteroids in the Main Belt

    CERN Document Server

    Moskovitz, Nicholas A; Gaidos, Eric; Willman, Mark; Nesvorny, David; Fevig, Ronald; Ivezic, Zeljko

    2008-01-01

    We present the observational results of a survey designed to target and detect asteroids whose colors are similar to those of Vesta family members and thus may be considered as candidates for having a basaltic composition. Fifty basaltic candidates were selected with orbital elements that lie outside of the Vesta dynamical family. Optical and near-infrared spectra were used to assign a taxonomic type to 11 of the 50 candidates. Ten of these were spectroscopically confirmed as V-type asteroids, suggesting that most of the candidates are basaltic and can be used to constrain the distribution of basaltic material in the Main Belt. Using our catalog of V-type candidates and the success rate of the survey, we calculate unbiased size-frequency and semi-major axis distributions of V-type asteroids. These distributions, in addition to an estimate for the total mass of basaltic material, suggest that Vesta was the predominant contributor to the basaltic asteroid inventory of the Main Belt, however scattered planetesim...

  18. A multi-domain approach to asteroid families identification

    CERN Document Server

    Carruba, V; Nesvorný, D; Roig, F; Huaman, M E; Souami, D

    2013-01-01

    Previous works have identified families halos by an analysis in proper elements domains, or by using Sloan Digital Sky Survey-Moving Object Catalog data, fourth release (SDSS-MOC4) multi-band photometry to infer the asteroid taxonomy, or by a combination of the two methods. The limited number of asteroids for which geometric albedo was known until recently discouraged in the past the extensive use of this additional parameter, which is however of great importance in identifying an asteroid taxonomy. The new availability of geometric albedo data from the Wide-field Infrared Survey Explorer (WISE) mission for about 100,000 asteroids significantly increased the sample of objects for which such information, with some errors, is now known. In this work we proposed a new method to identify families halos in a multi-domain space composed by proper elements, SDSS-MOC4 (a*,i-z) colors, and WISE geometric albedo for the whole main belt (and the Hungaria and Cybele orbital regions). Assuming that most families were crea...

  19. Sensitivity of Airburst Damage Prediction to Asteroid Characterization Uncertainty

    Science.gov (United States)

    Mathias, Donovan; Wheeler, Lorien; Dotson, Jessie L.

    2016-10-01

    Characterizing the level of risk posed by asteroid impacts is quintessential to developing informed mitigation criteria, response plans, and long-term survey and characterization strategies for potentially hazardous asteroids. A physics-based impact risk (PBIR) model has been created to assess the consequences of potential asteroid strikes by combining probabilistic sampling of uncertain impact parameters with numerical simulation of the atmospheric flight, breakup, and resulting ground damage for each sampled impact case. The model incudes a Monte Carlo framework that allows the uncertainties in the potential impact parameters to be described in terms of probability distributions, and produces statistical results that support inference regarding the threat level across those ranges. This work considers the PBIR model outputs in terms of potential threat characterization metrics for decision support. Several metrics are assessed, from the single estimated casualty (Ec) parameter to more descriptive distribution functions. Distributions are shown for aggregate risk, risk versus asteroid size, and risk to specific geographic regions. In addition, these results show how the uncertain properties of potential impactors can lead to different conclusions about optimal survey and characterization strategies.

  20. A retrograde co-orbital asteroid of Jupiter.

    Science.gov (United States)

    Wiegert, Paul; Connors, Martin; Veillet, Christian

    2017-03-29

    Recent theoretical work in celestial mechanics has revealed that an asteroid may orbit stably in the same region as a planet, despite revolving around the Sun in the sense opposite to that of the planet itself. Asteroid 2015 BZ509 was discovered in 2015, but with too much uncertainty in its measured orbit to establish whether it was such a retrograde co-orbital body. Here we report observations and analysis that demonstrates that asteroid 2015 BZ509 is indeed a retrograde co-orbital asteroid of the planet Jupiter. We find that 2015 BZ509 has long-term stability, having been in its current, resonant state for around a million years. This is long enough to preclude precise calculation of the time or mechanism of its injection to its present state, but it may be a Halley-family comet that entered the resonance through an interaction with Saturn. Retrograde co-orbital asteroids of Jupiter and other planets may be more common than previously expected.

  1. Hayabusa2 Sampler: Collection of Asteroidal Surface Material

    Science.gov (United States)

    Sawada, Hirotaka; Okazaki, Ryuji; Tachibana, Shogo; Sakamoto, Kanako; Takano, Yoshinori; Okamoto, Chisato; Yano, Hajime; Miura, Yayoi; Abe, Masanao; Hasegawa, Sunao; Noguchi, Takaaki

    2017-02-01

    Japan Aerospace Exploration Agency (JAXA) launched the asteroid exploration probe "Hayabusa2" in December 3rd, 2014, following the 1st Hayabusa mission. With technological and scientific improvements from the Hayabusa probe, we plan to visit the C-type asteroid 162137 Ryugu (1999 JU3), and to sample surface materials of the C-type asteroid that is likely to be different from the S-type asteroid Itokawa and contain more pristine materials, including organic matter and/or hydrated minerals, than S-type asteroids. We developed the Hayabusa2 sampler to collect a minimum of 100 mg of surface samples including several mm-sized particles at three surface locations without any severe terrestrial contamination. The basic configuration of the sampler design is mainly as same as the 1st Hayabusa (Yano et al. in Science, 312(5778):1350-1353, 2006), with several minor but important modifications based on lessons learned from the Hayabusa to fulfill the scientific requirements and to raise the scientific value of the returned samples. In this paper, we will report the details of the sampling system of Hayabusa2 with results of performance tests during the development and the current status of the sampling system.

  2. A retrograde co-orbital asteroid of Jupiter

    Science.gov (United States)

    Wiegert, Paul; Connors, Martin; Veillet, Christian

    2017-03-01

    Recent theoretical work in celestial mechanics has revealed that an asteroid may orbit stably in the same region as a planet, despite revolving around the Sun in the sense opposite to that of the planet itself. Asteroid 2015 BZ509 was discovered in 2015, but with too much uncertainty in its measured orbit to establish whether it was such a retrograde co-orbital body. Here we report observations and analysis that demonstrates that asteroid 2015 BZ509 is indeed a retrograde co-orbital asteroid of the planet Jupiter. We find that 2015 BZ509 has long-term stability, having been in its current, resonant state for around a million years. This is long enough to preclude precise calculation of the time or mechanism of its injection to its present state, but it may be a Halley-family comet that entered the resonance through an interaction with Saturn. Retrograde co-orbital asteroids of Jupiter and other planets may be more common than previously expected.

  3. Sub-Threshold Leakage Current Reduction Techniques In VLSI Circuits -A Survey

    Directory of Open Access Journals (Sweden)

    V.Sri Sai Harsha

    2015-09-01

    Full Text Available There is an increasing demand for portable devices powered up by battery, this led the manufacturers of semiconductor technology to scale down the feature size which results in reduction in threshold voltage and enables the complex functionality on a single chip. By scaling down the feature size the dynamic power dissipation has no effect but the static power dissipation has become equal or more than that of Dynamic power dissipation. So in recent CMOS technologies static power dissipation i.e. power dissipation due to leakage current has become a challenging area for VLSI chip designers. In order to prolong the battery life and maintain reliability of circuit, leakage current reduction is the primary goal. A basic overview of techniques used for reduction of sub-threshold leakages is discussed in this paper. Based on the surveyed techniques, one would be able to choose required and apt leakage reduction technique.

  4. Current Trends in Cloud Computing A Survey of Cloud Computing Systems

    Directory of Open Access Journals (Sweden)

    Harjit Singh

    2012-06-01

    Full Text Available Cloud computing that has become an increasingly important trend, is a virtualization technology that uses the internet and central remote servers to offer the sharing of resources that include infrastructures, software, applications and business processes to the market environment to fulfill the elastic demand. In today’s competitive environment, the service vitality, elasticity, choices and flexibility offered by this scalable technology are too attractive that makes the cloud computing to increasingly becoming an integral part of the enterprise computing environment. This paper presents a survey of the current state of Cloud Computing. It includes a discussion of the evolution process of cloud computing, characteristics of Cloud, current technologies adopted in cloud computing, This paper also presents a comparative study of cloud computing platforms (Amazon, Google and Microsoft, and its challenges.

  5. Reconstructing the spin distributions of main-belt asteroids

    Science.gov (United States)

    Holsapple, K.

    2014-07-01

    , and improve the analysis of those authors. The ejecta analysis is upgraded to include recent results on ejecta scaling (Housen and Holsapple 2011, Holsapple and Housen 2012). I use some recent experimental results about the efficiency of the angular momentum transfer efficiency (e.g., Yanagisawa and Hasegawa 2000) for oblique impacts. I also use more recent population estimates. Those considerations determine the outcome of a given single impact into a target asteroid. To estimate the cumulative effects of multiple impacts, one can take averages over the distributions of the impact velocities and angles. That was done in the above references; the key assumption was of a quadratic accumulation of spin magnitudes from averaged single impacts. However, here that approach is rejected, for two reasons. First, because of the momentum drain effect, the result of any one impact is not independent of the prior ones. The spin-up of a body is not a result of multiple random events. Second, it has been found that the current spin of an asteroid is more likely caused by a very few large impacts and not by an accumulation of random small ones. So, instead of a quadratic accumulation over averages, I've performed Monte Carlo analyses of the effects of a large number of impacts into a large number of target asteroids. The outcomes are distributions of spin versus asteroid size, which can then be compared to the actual data. SOME RESULTS: Analyses to date are interesting. First (and as found by others), the spins of the large asteroids cannot have resulted from impacts with the current population. Second, both the average spin and the maximum spin at any given size falls off with increasing asteroid size. Third, there exist ''average equilibrium spin states'', defined by a curve of spin versus diameter. For asteroids spinning faster than that state, the average next impact will always slow the spin; but for an asteroid with a spin below that state, the average impact will increase its

  6. Guide to the universe asteroids, comets, and dwarf planets

    CERN Document Server

    Rivkin, Andrew

    2009-01-01

    This volume in the Greenwood Guides to the Universe series covers asteroids, comets, and dwarf planets-those small bodies that revolve the Sun-and provides readers with the most up-to-date understanding of the current state of scientific knowledge about them. Scientifically sound, but written with the student in mind, Asteroids, Comets, and Dwarf Planets is an excellent first step for researching the exciting scientific discoveries of the smallest celestial bodies in the solar system.||The book will introduce students to all of the areas of research surrounding the subject, answering many intr

  7. Social Media Use Among Living Kidney Donors and Recipients: Survey on Current Practice and Potential.

    Science.gov (United States)

    Kazley, Abby Swanson; Hamidi, Bashir; Balliet, Wendy; Baliga, Prabhakar

    2016-12-20

    In the United States, there is a national shortage of organs donated for transplant. Among the solid organs, most often kidneys are donated by living donors, but the lack of information and complicated processes limit the number of individuals who serve as living kidney donors. Social media can be a tool for advocacy, educating the public about the need, process, and outcomes of live kidney donors, yet little is known about social media use by kidney transplant patients. The purpose of this study was to examine the social media use of potential kidney transplant patients and their willingness to use social media and their networks to advocate and educate about living kidney donation. Using a validated survey, we modified the instrument to apply to the patient population of interest attending the Medical University of South Carolina, Charleston, SC, USA. The questions on the survey inquired about current social media use, sites visited, frequency and duration of social media use, and willingness to use social media to share the need for living kidney donors. We asked patients who had received a transplant and those awaiting a transplant to complete the survey during an office visit. Participation was voluntary. A total of 199 patients completed the survey. Approximately half of all kidney transplant patients surveyed used social media (104/199, 52.3%), and approximately one-third (66/199, 33.2%) had more than 100 friends in their social media network. Facebook was the most popular site, and 51% (102/199) reported that they would be willing to post information about living kidney donation on their social networks. More than a quarter of the sample (75/199, 37.7%) had posted about their health status in the past. Social media holds great promise for health-related education and awareness. Our study shows the current social media use of kidney transplant patients. In turn, such information can be used to design interventions to ensure appropriate decision making about

  8. Flight status of robotic asteroid sample return mission Hayabusa2

    Science.gov (United States)

    Tsuda, Yuichi; Nakazawa, Satoru; Kushiki, Kenichi; Yoshikawa, Makoto; Kuninaka, Hitoshi; Watanabe, Seiichiro

    2016-10-01

    The Japan Aerospace Exploration Agency launched the asteroid sample return spacecraft "Hayabusa2" on December 3, 2014. Hayabusa2 will reach the C-type asteroid 1999 JU3 in 2018, and return back to the Earth in 2020. Sample collections from three sites, four surface rovers deployment and a 4 MJ-class kinetic impact crater generation are planned in the 1.5 years of the asteroid-proximity operation. The mission objective of Hayabusa2 has three aspects, science, engineering and exploration, all of which would be expanded by the successful round-trip journey. This paper describes the outline of the Hayabusa2 mission and the current flight status after the seven month of the interplanetary cruise.

  9. Excluding interlopers from asteroid families

    Science.gov (United States)

    Novakovic, B.; Radovic, V.

    2014-07-01

    Introduction: Asteroid families are believed to have originated from catastrophic collisions among asteroids. They are a very important subject of Solar System investigation, because practically any research topic carried out in asteroid-related science sooner or later encounters problems pertaining to asteroid families. One basic problem encountered when dealing with families is to determine reliably the list of its members, i.e. to reduce the number of interlopers as much as possible. This is an important problem, because many conclusions derived from analyses of the physical properties of family members must be necessarily based on firm and well established membership. However, as the number of known asteroids increases fast it becomes more and more difficult to obtain robust list of members of an asteroid family. To cope with these challenges we are proposing a new approach that may help to significantly reduce presence of interlopers among the family members. This method should be particularly useful once additional information become available, including primarily spectro-photometric data. This is exactly the kind of information that will be provided by Gaia. Metodology: Families (and their members) have been commonly identified by analysing the distribution of asteroids in the space of proper orbital elements, using the Hierarchical Clustering Method (HCM) [1]. A well-known drawback of the HCM based on the single linkage rule is the so-called chaining phenomenon: first concentrations naturally tend to incorporate nearby groups, forming a kind of 'chain'. Thus, any family membership obtained by the pure HCM must unavoidably include some interlopers. The method we are proposing here could be used to identify these interlopers, with its main advantage being an ability to significantly reduce the chaining effect. The method consists of three main steps. First we determine an asteroid family members by applying the HCM to the catalogue of proper elements obtained

  10. Current antimicrobial usage for the management of neutropenic fever in Korea: a nationwide survey.

    Science.gov (United States)

    Choi, Su-Mi; Park, Sun Hee; Lee, Dong-Gun; Choi, Jung-Hyun; Yoo, Jin-Hong; Shin, Wan-Shik

    2008-12-01

    A nationwide questionnaire-based survey was performed to evaluate the current clinical practices for the management of neutropenic fever in hematology units and hematopoietic stem cell transplantation (HSCT) centers throughout Korea. A 86.9% response rate was obtained from a total of 46 doctors and practical policies of the 33 sites were analysed. Approximately 42.4% and 84.8% of the sites responded that they used oral fluoroquinolone as prophylaxis for neutropenic patients receiving chemotherapy and HSCT, respectively. Additionally, 42.4% of the sites responded that they used antifungal prophylaxis in the chemotherapy groups whereas 90.9% of the sites responded that they used antifungal prophylaxis in HSCT recipients. Approximately half of the responding sites prescribed combination regimen with 3rd or 4th cephalosporin plus aminoglycoside as a first-line therapy. Most of the sites considered persistent fever for 2-4 days or aggravated clinical symptoms for 1-2 days as failure of the first-line regimen, and they changed antibiotics to second-line regimens that varied widely among the sites. Twenty-seven sites (84.4%) responded that they considered adding an antifungal agent when fever persisted for 5-7 days despite antibacterial therapy. Amphotericin B deoxycholate was preferred as a first-line antifungal, which was probably due to the limitations of the national health insurance system. The role of oral antibiotics in the management of neutropenic fever still accounted for a small portion. To the best of our knowledge, this survey is the first report to examine the practical policies currently in place for the management of neutropenic fever in Korea and the results of this survey may help to establish a Korean guideline in the future.

  11. Management of blunt extracranial traumatic cerebrovascular injury: a multidisciplinary survey of current practice

    Directory of Open Access Journals (Sweden)

    Cava Luis P

    2011-04-01

    Full Text Available Abstract Background Extracranial traumatic cerebrovascular injury (TCVI is present in 1-3% of all blunt force trauma patients. Although options for the management of patients with these lesions include anticoagulation, antiplatelet agents, and endovascular treatment, the optimal management strategy for patients with these lesions is not yet established. Objective Multidisciplinary survey of clinicians about current management of TCVI. Methods A six-item multiple-choice survey was sent by electronic mail to a total of 11,784 neurosurgeons, trauma surgeons, stroke neurologists, and interventional radiologists. The survey included questions about their choice of imaging, medical management, and the use of endovascular techniques. Survey responses were analyzed according to stated specialty. Results Seven hundred eighty-five (6.7% responses were received. Overall, a total of 325 (42.8% respondents favored anticoagulation (heparin and/or warfarin, 247 (32.5% favored antiplatelet drugs, 130 (17.1% preferred both anticoagulation and antiplatelet drugs, and 57 (7.5% preferred stenting and/or embolization. Anticoagulation was the most commonly preferred treatment among vascular surgeons (56.9%, neurologists (50.2% and neurosurgeons (40.7%, whereas antiplatelet agents were the most common preferred treatment among trauma surgeons (41.5%. Overall, 158 (20.7% of respondents recommended treatment of asymptomatic dissections and traumatic aneurysms, 211 (27.7% did not recommend it, and 39.4% recommended endovascular treatment only if there is worsening of the lesion on follow-up imaging. Conclusions These data demonstrate the wide variability of physicians' management of traumatic cerebrovascular injury, both on an individual basis, and between specialties. These findings underscore the need for multicenter, randomized trials in this field.

  12. Asteroid airburst altitude vs. strength

    Science.gov (United States)

    Robertson, Darrel; Wheeler, Lorien; Mathias, Donovan

    2016-10-01

    Small NEO asteroids (<Ø140m) may not be a threat on a national or global level but can still cause a significant amount of local damage as demonstrated by the Chelyabinsk event where there was over $33 million worth of damage (1 billion roubles) and 1500 were injured, mostly due to broken glass. The ground damage from a small asteroid depends strongly on the altitude at which they "burst" where most of the energy is deposited in the atmosphere. The ability to accurately predict ground damage is useful in determining appropriate evacuation or shelter plans and emergency management.Strong asteroids, such as a monolithic boulder, fail and create peak energy deposition close to the altitude at which ram dynamic pressure exceeds the material cohesive strength. Weaker asteroids, such as a rubble pile, structurally fail at higher altitude, but it requires the increased aerodynamic pressure at lower altitude to disrupt and disperse the rubble. Consequently the resulting airbursts have a peak energy deposition at similar altitudes.In this study hydrocode simulations of the entry and break-up of small asteroids were performed to examine the effect of strength, size, composition, entry angle, and speed on the resulting airburst. This presentation will show movies of the simulations, the results of peak burst height, and the comparison to semi-analytical models.

  13. The Double Asteroid Redirection Test (DART) for the AIDA Mission

    Science.gov (United States)

    Stickle, Angela; Cheng, Andy F.; Michel, Patrick; Barnouin, Olivier S.; Campo Bagatin, Adriano; Miller, Paul L.; Pravec, Petr; Richardson, Derek C.; Schwartz, Stephen R.; Tsiganis, Kleomenis; Ulamec, Stephan; AIDA Impact Modeling and Simulation Working Group

    2016-10-01

    The Asteroid Impact Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the NASA Double Asteroid Redirection Test (DART) mission, which provides the kinetic impactor, and the ESA Asteroid Impact Mission (AIM) rendezvous spacecraft. DART is a Phase A study supported by NASA, and AIM is a Phase B1 study supported by ESA. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make a close approach to Earth in October, 2022. The DART spacecraft is designed to impact the Didymos secondary at ~6 km/s and deflect its trajectory, changing the orbital period of the binary. This change can be measured by Earth-based optical and radar observations. The primary goals of AIDA are to (1) perform a full-scale demonstration of asteroid deflection by kinetic impact; (2) measure the resulting deflection; and (3) validate and improve models for momentum transfer in high-speed impacts on an asteroid. The combined DART and AIM missions will provide the first measurements of momentum transfer efficiency from a kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are also characterized. In addition to a predicted 4.4 minute change in the binary orbit period, assuming unit momentum transfer efficiency, the DART kinetic impact is predicted to induce forced librations of the Didymos secondary of possibly several degrees amplitude. Models predict the impact will create a 6-17 meter diameter crater, depending on target physical properties, and it will release a volume of particulate ejecta that may be directly observable from Earth or even resolvable as a coma or an ejecta tail by ground-based telescopes. Current simulations of the DART impact provide predictions for momentum transfer, crater size, and

  14. NASA's Near Earth Asteroid Scout Mission

    Science.gov (United States)

    Johnson, Les; McNutt, Leslie; Castillo-Rogez, Julie

    2017-01-01

    NASA is developing solar sail propulsion for a near-term Near Earth Asteroid (NEA) reconnaissance mission and laying the groundwork for their future use in deep space science and exploration missions. The NEA Scout mission, funded by NASA's Advanced Exploration Systems Program and managed by NASA MSFC, will use the sail as primary propulsion allowing it to survey and image one or more NEA's of interest for possible future human exploration. NEA Scout uses a 6U cubesat (to be provided by NASA's Jet Propulsion Laboratory), an 86 m2 solar sail and will weigh less than 14 kilograms. The solar sail for NEA Scout will be based on the technology developed and flown by the NASA NanoSail-D and The Planetary Society's Lightsail-A. Four 7 m stainless steel booms wrapped on two spools (two overlapping booms per spool) will be motor deployed and pull the sail from its stowed volume. The sail material is an aluminized polyimide approximately 3 microns thick. NEA Scout will launch on the Space Launch System (SLS) first mission in 2018 and deploy from the SLS after the Orion spacecraft is separated from the SLS upper stage. The NEA Scout spacecraft will stabilize its orientation after ejection using an onboard cold-gas thruster system. The same system provides the vehicle Delta-V sufficient for a lunar flyby. After its first encounter with the moon, the 86 m2 sail will deploy, and the sail characterization phase will begin. A mechanical Active Mass Translation (AMT) system, combined with the remaining ACS propellant, will be used for sail momentum management. Once the system is checked out, the spacecraft will perform a series of lunar flybys until it achieves optimum departure trajectory to the target asteroid. The spacecraft will then begin its two year-long cruise. About one month before the asteroid flyby, NEA Scout will pause to search for the target and start its approach phase using a combination of radio tracking and optical navigation. The solar sail will provide

  15. A survey on the current status of burn rehabilitation services in China.

    Science.gov (United States)

    Chen, Jian; Li-Tsang, Cecilia W P; Yan, Hong; Liang, Guangping; Tan, Jianglin; Yang, Sisi; Wu, Jun

    2013-03-01

    In China, there is a very long history of burn wound treatment, but the specialised burn care units were set up only from 1958. With more than 50 years of practice, great achievements have been made in burn wound care and operations in the country. However, in terms of burn rehabilitation, the development appears to be slow. In order to determine the current status of burn rehabilitation services in China, a survey was conducted to various burn centres in China. A comprehensive survey was conducted as well as to collect data related to (1) the admissions and staffing of the burn centres; (2) availability of rehabilitation services, number and educational background of specialised personnel dedicated in burn rehabilitation therapy; and (3) the difficulties leading to the lag of the burn rehabilitation services. The survey was sent to the chiefs of 87 burn centres via e-mail and they were requested to fill out the survey questionnaire and to send it back. For those who did not respond within 1 month, a reminder was sent. There are totally 39 (44.8%) burn centres responding to our survey. These centres were geographically distributed in nearly 70% of the administrative provinces in China; hence, the results could well represent the current burn care system. Most centres have recognised the importance of rehabilitation therapy and remarkable improvements of outcome in burn patients have been achieved. There are a very huge number of burn patients that need rehabilitation therapy, but most centres face the problems of shortage of rehabilitation therapists, which apparently could lead to the difficulties in delivering a quality rehabilitation programme for patients. Although the time of rehabilitation therapy is instituted far earlier than before, it is still not widely accepted in the acute burn care stage. There are more specialists joining the burn centre and becoming members of the professional burn team. However, professional education and training in the burn

  16. The Double Asteroid Redirection Test in the AIDA Mission

    Science.gov (United States)

    Cheng, Andrew; Reed, Cheryl; Rivkin, Andrew

    2016-07-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the ESA Asteroid Impact Mission (AIM) rendezvous mission and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The DART spacecraft is designed to impact the Didymos secondary at 7 km/s and demonstrate the ability to modify its trajectory through momentum transfer. DART and AIM are currently Phase A studies supported by NASA and ESA respectively. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the resulting changes of the binary orbit; and (3) study hyper-velocity collision effects on an asteroid, validating models for momentum transfer in asteroid impacts based on measured physical properties of the asteroid surface and sub-surface, and including long-term dynamics of impact ejecta. The primary DART objectives are to demonstrate a hyper-velocity impact on the Didymos moon and to determine the resulting deflection from ground-based observations. The DART impact on the Didymos secondary will change the orbital period of the binary which can be measured by supporting Earth-based optical and radar observations. The baseline DART mission launches in December, 2020 to impact the Didymos secondary in September,2022. There are multiple launch opportunities for DART leading to impact around the 2022 Didymos close approach to Earth. The AIM spacecraft will be launched in Dec. 2020 and arrive at Didymos in spring, 2022, several months before the DART impact. AIM will characterize the Didymos binary system

  17. Current status of paediatric post-mortem imaging: an ESPR questionnaire-based survey

    Energy Technology Data Exchange (ETDEWEB)

    Arthurs, Owen J. [Great Ormond Street Hospital for Children NHS Foundation Trust, Department of Radiology, London (United Kingdom); University College London, Institute of Child Health, London (United Kingdom); Rijn, Rick R. van [Academic Medical Centre, Department of Radiology, Amsterdam (Netherlands); Sebire, Neil J. [Great Ormond Street Hospital for Children, Department of Pathology, London (United Kingdom); University College London, Institute of Child Health, London (United Kingdom)

    2014-03-15

    The use of post-mortem imaging, including skeletal radiography, CT and MRI, is increasing, providing a minimally invasive alternative to conventional autopsy techniques. The development of clinical guidelines and national standards is being encouraged, particularly for cross-sectional techniques. To outline the current practice of post-mortem imaging amongst members of the European Society of Paediatric Radiology (ESPR). We e-mailed an online questionnaire of current post-mortem service provisions to members of the ESPR in January 2013. The survey included direct questions about what services were offered, the population imaged, current techniques used, imaging protocols, reporting experience and intended future involvement. Seventy-one percent (47/66) of centres from which surveys were returned reported performing some form of post-mortem imaging in children, of which 81 % perform radiographs, 51% CT and 38% MRI. Eighty-seven percent of the imaging is performed within the radiology or imaging departments, usually by radiographers (75%), and 89% is reported by radiologists, of which 64% is reported by paediatric radiologists. Overall, 72% of positive respondents have a standardised protocol for radiographs, but only 32% have such a protocol for CT and 27% for MRI. Sixty-one percent of respondents wrote that this is an important area that needs to be developed. Overall, the majority of centres provide some post-mortem imaging service, most of which is performed within an imaging department and reported by a paediatric radiologist. However, the populations imaged as well as the details of the services offered are highly variable among institutions and lack standardisation. We have identified people who would be interested in taking this work forwards. (orig.)

  18. A Gravitational Tractor for Towing Asteroids

    CERN Document Server

    Lu, E T; Lu, Edward T.; Categories, Stanley G. Love

    2005-01-01

    We present a concept for a spacecraft that can controllably alter the trajectory of an Earth threatening asteroid using gravity as a towline. The spacecraft hovers near the asteroid with thrusters angled outward so the exhaust does not impinge on the surface. This deflection method is insensitive to the structure, surface properties, and rotation state of the asteroid.

  19. Teaching Intercultural Communication in a Basic Technical Writing Course: A Survey of Our Current Practices and Methods

    Science.gov (United States)

    Matveeva, Natalia

    2008-01-01

    This research article reports the results of an online survey distributed among technical writing instructors in 2006. The survey aimed to examine how we teach intercultural communication in basic technical writing courses: our current practices and methods. The article discusses three major challenges that instructors may face when teaching about…

  20. A Study of Current Trends and Issues for Graphics Education: Results from a Five-Year Follow-Up Survey

    Science.gov (United States)

    Clark, Aaron C.; Scales, Alice Y.

    2006-01-01

    During the 1998-1999 academic year, a survey was conducted to look at current trends and issues in the profession of graphics education (Clark & Scales, 1999). The survey solicited information from the membership of the Engineering Design Graphics Division of the American Society for Engineering Education related to their view of future areas of…

  1. Benchmarking Asteroid-Deflection Experiment

    Science.gov (United States)

    Remington, Tane; Bruck Syal, Megan; Owen, John Michael; Miller, Paul L.

    2016-10-01

    An asteroid impacting Earth could have devastating consequences. In preparation to deflect or disrupt one before it reaches Earth, it is imperative to have modeling capabilities that adequately simulate the deflection actions. Code validation is key to ensuring full confidence in simulation results used in an asteroid-mitigation plan. We are benchmarking well-known impact experiments using Spheral, an adaptive smoothed-particle hydrodynamics code, to validate our modeling of asteroid deflection. We describe our simulation results, compare them with experimental data, and discuss what we have learned from our work. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-695540

  2. Thermal-Infrared Surveys of Near-Earth Object Diameters and Albedos with Spitzer and IRTF/MIRSI

    NARCIS (Netherlands)

    Mommert, Michael; Trilling, David; Hora, Joseph L.; Chesley, Steven; Emery, Josh; Fazio, Giovanni; Harris, Alan W.; Moskovitz, Nick; Mueller, Michael; Smith, Howard

    2015-01-01

    More than 12000 Near-Earth Objects (NEOs) have been discovered over the past few decades and current discovery surveys find on average 4 new NEOs every night. In comparison to asteroid discovery, the physical characterization of NEOs lags far behind: measured diameters and albedos exist only for rou

  3. The Asteroid Impact Mission (AIM): Studying the geophysics of small binaries, measuring asteroid deflection and studying impact physics

    Science.gov (United States)

    Kueppers, Michael; Michel, Patrick; AIM Team

    2016-10-01

    Binary asteroids and their formation mechanisms are of particular interest for understanding the evolution of the small bodies in the solar system. Also, hazards to Earth from impact of near-Earth asteroids and their mitigation have drawn considerable interest over the last decades.Those subjects are both addressed by ESA's Asteroid Impact mission, which is part of the Asteroid Impact & Deflection Assessment (AIDA) currently under study in collaboration between NASA and ESA. NASA's DART mission will impact a projectile into the minor component of the binary near-Earth asteroid (65803) Didymos in 2022. The basic idea is to demonstrate the effect of the impact on the orbital period of the secondary around the primary. ESA's AIM will monitor the Didymos system for several months around the DART impact time.AIM will be launched in aurumn 2020. It is foreseen to arrive at Didymos in April 2022. The mission takes advantage of a close approach of Didymos to Earth. The next opportunity would arise in 2040 only.AIM will stay near Didymos for approximately 6 months. Most of the time it will be placed on the illuminated side of the system, at distances of approximately 35 km and 10 km. AIM is expected to move away from Didymos for some time around the DART impact.The reference payload for AIM includes two visual imagers, a hyperspectral camera, a lidar, a thermal infrared imager, a monostatic high frequency radar, and a bistatic low frequency radar. In addition, AIM will deploy a small lander on the secondary asteroid, and two cubesats that will be used for additional, more risky investigations close to or on the surface of the asteroid.Major contributions from AIM are expected in the study of the geophysics of small asteroids (including for the first time, radar measurements of an interior structure), the formation of binary asteroids, the momentum enhancement factor from the DART impact (through measuring the mass and the change of orbit of the seondary), and impact physics

  4. On future opportunities to observe gravitational scattering of main belt asteroids into NEO source regions

    Science.gov (United States)

    Ivantsov, A.; Eggl, S.; Hestroffer, D.; Thuillot, W.

    2014-12-01

    Physical and orbital properties of the current NEO population can be explained when one assumes that their primary origin lies in the asteroid main-belt and Jupiter-family comet (PMorbidelli et al. 2002).

  5. Dynamics of Rotationally Fissioned Asteroids

    Science.gov (United States)

    Jacobson, Seth A.; Scheeres, D. J.

    2010-10-01

    We present a model for near-Earth asteroid (NEA) rotational fission that results in the evolution of all observed types of NEA systems: synchronous binaries, asteroid pairs, doubly synchronous binaries, high-e binaries, ternary systems, and contact binaries. The model consists of "rubble pile” asteroid geophysics, the YORP and binary YORP effects, and mutual gravitational interactions. An NEA can be modeled as a ``rubble pile"--a collection of gravitationally bound boulders with a distribution of size scales and very little tensile strength between them. The YORP effect torques a "rubble pile” asteroid until the asteroid reaches its disruption spin limit, and then two collections of boulders will enter into orbit about each other determined by the largest distance between mass centers. This binary system dynamically evolves under the effects of non-spherical gravitational potentials, solar gravitational perturbations, and mutual body tides. The coupling between the spin states and orbit state chaotically drives the system into the observed asteroid classes with mass ratio, q, distinguishing two evolutionary tracks. High mass ratio systems, q>0.2, evolve tidally into doubly synchronous binaries and then continued to be evolved by BYORP. Low mass ratio systems, qfission, creating a chaotic ternary system. We call this new process secondary fission. The resulting triple system may eject one body or, more often, send one into a slow speed impact with the primary. These processes tend to stabilize the initially chaotic binaries to create synchronous binaries. These results emphasize the importance of the initial component size distribution and configuration within the parent body. This work is supported by NASA's PGG and OPR programs through grants: NNX08AL51G and NNX09AU23G.

  6. Project RAMA: Reconstructing Asteroids Into Mechanical Automata

    Science.gov (United States)

    Dunn, Jason; Fagin, Max; Snyder, Michael; Joyce, Eric

    2017-01-01

    Many interesting ideas have been conceived for building space-based infrastructure in cislunar space. From O'Neill's space colonies, to solar power satellite farms, and even prospecting retrieved near earth asteroids. In all the scenarios, one thing remained fixed - the need for space resources at the outpost. To satisfy this need, O'Neill suggested an electromagnetic railgun to deliver resources from the lunar surface, while NASA's Asteroid Redirect Mission called for a solar electric tug to deliver asteroid materials from interplanetary space. At Made In Space, we propose an entirely new concept. One which is scalable, cost effective, and ensures that the abundant material wealth of the inner solar system becomes readily available to humankind in a nearly automated fashion. We propose the RAMA architecture, which turns asteroids into self-contained spacecraft capable of moving themselves back to cislunar space. The RAMA architecture is just as capable of transporting conventional-sized asteroids on the 10-meter length scale as transporting asteroids 100 meters or larger, making it the most versatile asteroid retrieval architecture in terms of retrieved-mass capability. This report describes the results of the Phase I study funded by the NASA NIAC program for Made In Space to establish the concept feasibility of using space manufacturing to convert asteroids into autonomous, mechanical spacecraft. Project RAMA, Reconstituting Asteroids into Mechanical Automata, is designed to leverage the future advances of additive manufacturing (AM), in-situ resource utilization (ISRU) and in-situ manufacturing (ISM) to realize enormous efficiencies in repeated asteroid redirect missions. A team of engineers at Made In Space performed the study work with consultation from the asteroid mining industry, academia, and NASA. Previous studies for asteroid retrieval have been constrained to studying only asteroids that are both large enough to be discovered, and small enough to be

  7. Detection and location of leaks in district heating steam systems: Survey and review of current technology and practices

    Energy Technology Data Exchange (ETDEWEB)

    Kupperman, D.S.; Raptis, A.C.; Lanham, R.N.

    1992-03-01

    This report presents the results of a survey undertaken to identify and characterize current practices for detecting and locating leaks in district heating systems, particular steam systems. Currently used technology and practices are reviewed. In addition, the survey was used to gather information that may be important for the application of acoustic leak detection. A few examples of attempts to locate leaks in steam and hot water pipes by correlation of acoustic signals generated by the leaks are also discussed.

  8. A Search for Subkilometer-sized Ordinary Chondrite Like Asteroids in the Main-Belt

    CERN Document Server

    Lin, H W; Chen, Y T; Ip, W H; Chang, C K

    2015-01-01

    The size-dependent effects of asteroids on surface regolith and collisional lifetimes suggest that small asteroids are younger than large asteroids. In this study, we performed multicolor main-belt asteroid (MBA) survey by Subaru telescope/Suprime-Cam to search for subkilometer-sized ordinary chondrite (Q-type) like MBAs. The total survey area was 1.5 deg^2 near ecliptic plane and close to the opposition. We detected 150 MBAs with 4 bands (B, V , R, I) in this survey. The range of absolute magnitude of detected asteroids was between 13 and 22 magnitude, which is equivalent to the size range of kilometer to sub-kilometer diameter in MBAs. From this observation, 75 of 150 MBAs with color uncertainty less than 0.1 were used in the spectral type analysis, and two possible Q-type aster- oids were detected. This mean that the Q-type to S-type ratio in MBAs is < 0.05. Meanwhile, the Q/S ratio in near Earth asteroids (NEAs) has been estimated to be 0.5 to 2 (Binzel et al., 2004; Dandy et al., 2003). Therefore, Q-t...

  9. LSST's Projected Near-Earth Asteroid Discovery Performance

    Science.gov (United States)

    Chesley, Steven R.; Veres, Peter

    2016-10-01

    The Large Synoptic Survey Telescope (LSST) is an ambitious project that has the potential to make major advances in Near-Earth Asteroid search efforts. With construction already underway and major optical elements complete, first light is set for 2020, followed by two years of commissioning. Once regular survey operations begin in 2022, LSST will systematically survey the observable sky over a ten-year period from its site on Cerro Pachon, Chile. With an 8.4 m aperture (6.5 m effective), 9.6 square degree field of view, and a 3.2-Gigapixel camera, LSST represents the most capable asteroid survey instrument ever built. LSST will be able cover over 6000 square degrees of sky per clear night with single visit exposures of 30 s, reaching a faint limit of 24.5 mag in the r band. However the cadence of survey operations is a critical factor for the near-Earth asteroid search performance, and there are multiple science drivers with different cadence objectives that are competing to shape the final survey strategy. We examine the NEA search performance of various LSST search strategies, paying particular attention to the challenges of linking large numbers asteroid detections in the presence of noise. Our approach is to derive lists of synthetic detections for a given instantiation of the LSST survey, based on an assumed model for the populations of solar system objects from the main asteroid belt inwards to the near-Earth population. These detection lists are combined with false detection lists that model both random noise and non-random artifacts resulting from image differencing algorithms. These large detection lists are fed to the Moving Object Processing System (MOPS), which attempts to link the synthetic detections correctly without becoming confused or overwhelmed by the false detections. The LSST baseline survey cadence relies primarily on single night pairs of detections, with roughly 30-60 min separating elements of the pair. The strategy of using pairs is an

  10. The Micro-mechanics of Asteroid Dust

    Science.gov (United States)

    Sanchez Lana, Diego Paul; Scheeres, Daniel J.

    2016-10-01

    Current understanding is that small asteroids in the Solar System are gravitational aggregates that are held together by gravitational, cohesive and adhesive forces. Though the mechanics of how gravitational forces work is very well understood, the same cannot be said about the other two.In our earlier research we used a Discrete-Element-Method simulation code to calculate the tensile strength of an assemblage of cohesive particles and found that the main geometrical factor controlling bulk strength was the average size of the particles (Sanchez and Scheeres 2014, MAPS). Specifically, the smaller the average size, the greater the tensile strength as r^-1, as though the magnitude of the van der Waals force applied decrease with the radius of the grains (r), the number of contacts per unit area increases with r^-2. This dependency has been corroborated by some observational evidence of the global strength of granular asteroids; however, our simulations were carried out with spherical particles and therefore in these simulations it is impossible to consider more than one contact per pair of particles. Other parameters such as different chemical composition and wider size distribution of the grains, changes in porosity and number of contacts per particle (coordination number) were not taken into direct account either. The study of each one of these parameters is of interest, and our research has started to explore the effect of these on the net cohesive force found in an asteroid's regolith and interior.Our initial study will simulate the effect of a wider size distribution in the granular material, comparing this with theoretical predictions. This parameter can cause a change in porosity and coordination number of the grains. This will have a measurable effect in the tensile strength of the aggregate and will provide a first look into the strength of a more realistic cohesive granular media. The results of this research will be shown at the conference.

  11. Growth monitoring: a survey of current practices of primary care paediatricians in Europe.

    Directory of Open Access Journals (Sweden)

    Pauline Scherdel

    Full Text Available OBJECTIVE: We aimed to study current practices in growth monitoring by European primary care paediatricians and to explore their perceived needs in this field. METHODS: We developed a cross-sectional, anonymous on-line survey and contacted primary care paediatricians listed in national directories in the 18 European countries with a confederation of primary care paediatricians. Paediatricians participated in the survey between April and September 2011. RESULTS: Of the 1,198 paediatricians from 11 European countries (response rate 13% who participated, 29% used the 2006 World Health Organization Multicentre Growth Reference Study growth charts, 69% used national growth charts; 61% used software to draw growth charts and 79% did not use a formal algorithm to detect abnormal growth on growth charts. Among the 21% of paediatricians who used algorithms, many used non-algorithmic simple thresholds for height and weight and none used the algorithms published in the international literature. In all, 69% of paediatricians declared that a validated algorithm to monitor growth would be useful in daily practice. We found important between-country variations. CONCLUSION: The varied growth-monitoring practices declared by primary care paediatricians reveals the need for standardization and evidence-based algorithms to define abnormal growth and the development of software that would use such algorithms.

  12. Aspirin desensitization in patients undergoing percutaneous coronary intervention: a survey of current practice.

    Science.gov (United States)

    Chapman, Andrew R; Rushworth, Gordon F; Leslie, Stephen J

    2013-01-01

    Aspirin remains the mainstay of anti-platelet therapy in cardiac patients. However, if a patient is allergic to aspirin and dual anti-platelet therapy is indicated - such as with percutaneous coronary intervention (PCI), then there is no clear guidance. One possibility is aspirin desensitization. A variety of protocols exist for the rapid desensitization of patients with aspirin allergy. The aim of this survey was to assess current knowledge and practice regarding aspirin desensitization in the UK. We conducted a UK wide survey of all UK 116 PCI centers and obtained complete responses from 40 (35.4%) centers. Of these, just 7 (17.5%) centers had previously desensitised patients; 29 (87.9%) centers suggested a lack of a local protocol prevented them from desensitizing, with 10 (30.3%) unsure of how to conduct desensitization. Only 5 (12.5%) centers had a local policy for aspirin desensitization although 25 (64.1%) units had a clinical strategy for dealing with aspirin allergy; the majority (72%) giving higher doses of thienopyridine class drugs. In the UK, there appears to be no consistent approach to patients with aspirin allergy. Patients undergoing PCI benefit from dual anti-platelet therapy (including aspirin), and aspirin desensitization in those with known allergy may facilitate this. Sustained effort should be placed on encouraging UK centers to use desensitization as a treatment modality prior to PCI rather than avoiding aspirin altogether.

  13. Questionnaire survey regarding the current status of super-extended lymph node dissection in Japan

    Science.gov (United States)

    Morita, Shinji; Fukagawa, Takeo; Fujiwara, Hisataka; Katai, Hitoshi

    2016-01-01

    AIM To verify the current status of super-extended lymph node dissection for advanced gastric cancer according to a questionnaire survey. METHODS One-hundred and five institutions responded to the questionnaire. The survey included the following items: Number of experiences, whether performed prophylactically and/or therapeutically, whether preoperative chemotherapy was provided, number of preoperative chemotherapy rounds, and therapeutic options after chemotherapy. RESULTS Eighty-seven of the 105 institutions (83%) had performed D3 gastrectomy in the past or continued to perform D3 gastrectomy at present. However, D3 gastrectomy was rarely performed prophylactically in clinical practice. Seventy-eight institutions (74%) indicated that preoperative chemotherapy with curative intent was required for patients suspected of having para-aortic node (PAN) metastases. After chemotherapy, a D3 gastrectomy was scheduled for patients with a complete or partial response, stable disease, and progressive disease at 36 (46%), 28 (36%), and 13 (17%) of the institutions, respectively. CONCLUSION For patients with apparent PAN metastasis, a D3 gastrectomy is typically planned if a few courses of preoperative chemotherapy yield at least a stable disease condition. PMID:27672429

  14. Neoadjuvant chemotherapy use in bladder cancer: a survey of current practice and opinions.

    Science.gov (United States)

    Cowan, N G; Chen, Y; Downs, T M; Bochner, B H; Apolo, A B; Porter, M P; La Rochelle, J C; Amling, C L; Koppie, T M

    2014-01-01

    Objectives. Level 1 evidence supports the use of neoadjuvant chemotherapy (NAC) to improve overall survival in muscle invasive bladder cancer; however utilization rates remain low. The aims of our study were to determine factors associated with NAC use, to more clearly define reasons for low utilization, and to determine the current rate of NAC use among urologic oncologists. Materials and Methods. Active members of the Society for Urologic Oncology were provided a 20-question survey. Descriptive statistical analysis was conducted for each question and univariate analysis was performed. Results. We achieved a response rate of 21%. Clinical T3/T4 disease was the most often selected reason for recommending NAC (87%). Concerns with recommending NAC were age and comorbidities (54%) followed by delay in surgery (35%). An association was identified between urologic oncologists who discussed NAC with >90% of their patients and medical oncologists "always" recommending NAC (P = 0.0009). NAC utilization rate was between 30 and 57%. Conclusions. Amongst this highly specialized group of respondents, clinical T3-T4 disease was the most common reason for implementation of NAC. Respondents who frequently discussed NAC were more likely to report their medical oncologist always recommending NAC. Reported NAC use was higher in this surveyed group (30-57%) compared with recently published rates.

  15. Neoadjuvant Chemotherapy Use in Bladder Cancer: A Survey of Current Practice and Opinions

    Directory of Open Access Journals (Sweden)

    N. G. Cowan

    2014-01-01

    Full Text Available Objectives. Level 1 evidence supports the use of neoadjuvant chemotherapy (NAC to improve overall survival in muscle invasive bladder cancer; however utilization rates remain low. The aims of our study were to determine factors associated with NAC use, to more clearly define reasons for low utilization, and to determine the current rate of NAC use among urologic oncologists. Materials and Methods. Active members of the Society for Urologic Oncology were provided a 20-question survey. Descriptive statistical analysis was conducted for each question and univariate analysis was performed. Results. We achieved a response rate of 21%. Clinical T3/T4 disease was the most often selected reason for recommending NAC (87%. Concerns with recommending NAC were age and comorbidities (54% followed by delay in surgery (35%. An association was identified between urologic oncologists who discussed NAC with >90% of their patients and medical oncologists “always” recommending NAC (P=0.0009. NAC utilization rate was between 30 and 57%. Conclusions. Amongst this highly specialized group of respondents, clinical T3-T4 disease was the most common reason for implementation of NAC. Respondents who frequently discussed NAC were more likely to report their medical oncologist always recommending NAC. Reported NAC use was higher in this surveyed group (30–57% compared with recently published rates.

  16. Metastatic bone lesions in children, current assessment of radionuclide skeletal survey

    Energy Technology Data Exchange (ETDEWEB)

    Zucker, J.M.; Gongora, R.; Michon, J.; Gongora, G.; Quintana-Margulis, E. (Institut Curie, Paris (France))

    Bone scintigraphy is more sensitive than radiographic skeletal survey in early diagnosis of bone metastases from pediatric solid tumors. Organic phosphorus compounds of labelled 99 m technetium are currently the far most used, and the pattern of imaging is compared to normal skeletal distribution of the radionuclide in childhood. From the most important series of the recent literature and their own experience, the authors ask the value of the procedure and describe overall results: a reliable diagnosis of bone metastases is done in 25 to 50% of the metastatic patients several weeks or months earlier than by radiographs: false positive are rarely misleading if usual pitfalls have been discarded: false negative are encountered in approximately 10% of the cases: post-therapeutic changes may be confusing. Some more details are given for neuroblastoma in which ''cold'' metastases and symetrical long bone's metaphysis involvement may display a misleading aspect. The selective uptake of the tracer by the primary is also underlined in this tumor. Finally indications of radionuclide skeletal survey, -at diagnosis and during and after the treatment-, are proposed for patients at risk amongst children with malignant solid tumors.

  17. Current trends in pulp therapy: a survey analyzing pulpotomy techniques taught in pediatric dental residency programs.

    Science.gov (United States)

    Walker, Laquia A; Sanders, Brian J; Jones, James E; Williamson, C Andrew; Dean, Jeffrey A; Legan, Joseph J; Maupome, Gerardo

    2013-01-01

    The study's purpose was to survey directors of pediatric dental residency programs in order to evaluate the materials currently being taught and used for pulpotomy procedures for primary teeth in educational and clinical settings. A web-based survey was emailed to all graduate pediatric dental residency program directors in the United States. Seventy one emails were sent to program directors, 47 responded but only 39 respondents (55%) were included in the study. Results suggested a slight decrease in utilization of formocresol 1:5 dilution (Pformocresol (18% of respondents) were systemic health concerns and carcinogenicity, in addition to evidence-based literature. Even though 25% of respondents have begun to use MTA for primary pulpotomy procedures, the most common reason for utilization of other medicaments over MTA was its higher cost. With 82% of graduate pediatric dental residency programs still utilizing formocresol 1:5 dilution for pulpotomy procedures in primary teeth, there has been no major shift away from its clinical use, in spite of increased usage of newer medicaments over the last 5 years.

  18. Flying Through Dust From Asteroids

    Science.gov (United States)

    Kohler, Susanna

    2016-11-01

    How can we tell what an asteroid is made of? Until now, weve relied on remote spectral observations, though NASAs recently launched OSIRIS-REx mission may soon change this by landing on an asteroid and returning with a sample.But what if we could learn more about the asteroids near Earth without needing to land on each one? It turns out that we can by flying through their dust.The aerogel dust collector of the Stardust mission. [NASA/JPL/Caltech]Ejected CluesWhen an airless body is impacted by the meteoroids prevalent throughout our solar system, ejecta from the body are flung into the space around it. In the case of small objects like asteroids, their gravitational pull is so weak that most of the ejected material escapes, forming a surrounding cloud of dust.By flying a spacecraft through this cloud, we could perform chemical analysis of the dust, thereby determining the asteroids composition. We could even capture some of the dust during a flyby (for example, by using an aerogel collector like in the Stardust mission) and bring it back home to analyze.So whats the best place to fly a dust-analyzing or -collecting spacecraft? To answer this, we need to know what the typical distribution of dust is around a near-Earth asteroid (NEA) a problem that scientists Jamey Szalay (Southwest Research Institute) and Mihly Hornyi (University of Colorado Boulder) address in a recent study.The colors show the density distribution for dust grains larger than 0.3 m around a body with a 10-km radius. The distribution is asymmetric, with higher densities on the apex side, shown here in the +y direction. [Szalay Hornyi 2016]Moon as a LaboratoryTo determine typical dust distributions around NEAs, Szalay and Hornyi first look at the distribution of dust around our own Moon, caused by the same barrage of meteorites wed expect to impact NEAs. The Moons dust cloud was measured in situ in 2013 and 2014 by the Lunar Dust Experiment (LDEX) on board the Lunar Atmosphere and Dust Environment

  19. Debriefing after failed paediatric resuscitation: a survey of current UK practice.

    Science.gov (United States)

    Ireland, S; Gilchrist, J; Maconochie, I

    2008-06-01

    Debriefing is a form of psychological "first aid" with origins in the military. It moved into the spotlight in 1983, when Mitchell described the technique of critical incident stress debriefing. To date little work has been carried out relating to the effectiveness of debriefing hospital staff after critical incidents. The aim of this study was to survey current UK practice in order to develop some "best practice" guidelines. This study was a descriptive evaluation based on a structured questionnaire survey of 180 lead paediatric and emergency medicine consultants and nurses, selected from 50 UK trusts. Questions collected data about trust policy and events and also about individuals' personal experience of debrief. Free text comments were analyzed using the framework method described for qualitative data. Overall, the response rate was 80%. 62% said a debrief would occur most of the time. 85% reported that the main aim was to resolve both medical and psychological and emotional issues. Nearly all involve both doctors and nurses (88%); in over half (62%) other healthcare workers would be invited, eg, paramedics, students. Sessions are usually led by someone who was involved in the resuscitation attempt (76%). This was a doctor in 80%, but only 18% of responders said that a specifically trained person had led the session. Individuals' psychological issues would be discussed further on a one-to-one basis and the person directed to appropriate agencies. Any strategic working problems highlighted would be discussed with a senior member of staff and resolved via clinical governance pathways. Little is currently known about the benefits of debriefing hospital staff after critical incidents such as failed resuscitation. Debriefing is, however, widely practised and the results of this study have been used to formulate some best practice guidelines while awaiting evidence from further studies.

  20. Surveys, Astrometric Follow-up & Population Statistics

    CERN Document Server

    Jedicke, Robert; Micheli, Marco; Ryan, Eileen; Spahr, Timothy; Yeomans, Donald K

    2015-01-01

    Asteroid surveys are the backbone of asteroid science, and with this in mind we begin with a broad review of the impact of asteroid surveys on our field. We then provide a brief history of asteroid discoveries so as to place contemporary and future surveys in perspective. Surveys in the United States have discovered the vast majority of the asteroids and this dominance has been consolidated since the publication of Asteroids III. Our descriptions of the asteroid surveys that have been operational since that time are focussed upon those that have contributed the vast majority of asteroid observations and discoveries. We also provide some insight into upcoming next-generation surveys that are sure to alter our understanding of the small bodies in the inner solar system and provide evidence to untangle their complicated dynamical and physical histories. The Minor Planet Center, the nerve center of the asteroid discovery effort, has improved its operations significantly in the past decade so that it can manage th...

  1. Are There Meteors Originated from Near Earth Asteroid (25143) Itokawa?

    CERN Document Server

    Ohtsuka, K; Abe, M; Yano, H; Watanabe, J

    2008-01-01

    As a result of a survey of Itokawid meteors (i.e., meteors originated from Near Earth Asteroid (25143) Itokawa = 1998SF36), from among the multi-station optical meteor orbit data of ~15000 orbits, and applying the D-criteria, we could find five Itokawid meteor candidates. We also analyzed corresponding mineral materials of the Itokawid candidates through their trajectory and atmospheric data. We conclude, on the basis of our investigation, that the fireball, MORP172, is the strongest Itokawid candidate.

  2. Astronomical Observations of Volatiles on Asteroids

    CERN Document Server

    Rivkin, Andrew S; Emery, Joshua P; Howell, Ellen S; Licandro, Javier; Takir, Driss; Vilas, Faith

    2015-01-01

    We have long known that water and hydroxyl are important components in meteorites and asteroids. However, in the time since the publication of Asteroids III, evolution of astronomical instrumentation, laboratory capabilities, and theoretical models have led to great advances in our understanding of H2O/OH on small bodies, and spacecraft observations of the Moon and Vesta have important implications for our interpretations of the asteroidal population. We begin this chapter with the importance of water/OH in asteroids, after which we will discuss their spectral features throughout the visible and near-infrared. We continue with an overview of the findings in meteorites and asteroids, closing with a discussion of future opportunities, the results from which we can anticipate finding in Asteroids V. Because this topic is of broad importance to asteroids, we also point to relevant in-depth discussions elsewhere in this volume.

  3. Astronomical observations of volatiles on asteroids

    Science.gov (United States)

    Rivkin, Andrew S.; Campins, Humberto; Emery, Joshua P.; Howell, Ellen S.; Licandro, Javier; Takir, Driss; Vilas, Faith; Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

    2015-01-01

    We have long known that water and hydroxyl are important components in meteorites and asteroids. However, in the time since the publication of Asteroids III, evolution of astronomical instrumentation, laboratory capabilities, and theoretical models have led to great advances in our understanding of H2O/OH on small bodies, and spacecraft observations of the Moon and Vesta have important implications for our interpretations of the asteroidal population. We begin this chapter with the importance of water/OH in asteroids, after which we will discuss their spectral features throughout the visible and near-infrared. We continue with an overview of the findings in meteorites and asteroids, closing with a discussion of future opportunities, the results from which we can anticipate finding in Asteroids V. Because this topic is of broad importance to asteroids, we also point to relevant in-depth discussions elsewhere in this volume.

  4. Asteroid taxonomic signatures from photometric phase curves

    CERN Document Server

    Oszkiewicz, D A; Wasserman, L H; Muinonen, K; Penttilä, A; Pieniluoma, T; Trilling, D E; Thomas, C A

    2012-01-01

    We explore the correlation between an asteroid's taxonomy and photometric phase curve using the H, G12 photometric phase function, with the shape of the phase function described by the single parameter G12. We explore the usability of G12 in taxonomic classification for individual objects, asteroid families, and dynamical groups. We conclude that the mean values of G12 for the considered taxonomic complexes are statistically different, and also discuss the overall shape of the G12 distribution for each taxonomic complex. Based on the values of G12 for about half a million asteroids, we compute the probabilities of C, S, and X complex membership for each asteroid. For an individual asteroid, these probabilities are rather evenly distributed over all of the complexes, thus preventing meaningful classification. We then present and discuss the G12 distributions for asteroid families, and predict the taxonomic complex preponderance for asteroid families given the distribution of G12 in each family. For certain ast...

  5. Serendipitous asteroid observations by OSIRIS/Rosetta

    Science.gov (United States)

    Carry, B.; Berthier, J.; Vachier, F.; Küppers, M.

    2012-09-01

    In recent years, many efforts have been undertaken to extract the astrometry, photometry, and colors of Solar System Small Bodies from large surveys and widefield camera, such as the SDSS Moving Object Catalog [2] or EuroNear [3]. Since 2006, the IMCCE provides a service, called SkyBoT [1], that list all the Solar System Objects in a given field of view for a given epoch. Such a tool is of high interest for any data mining purpose of large archives. We will present an extension of SkyBoT from ground-based to space-based geometries. As a demonstration, we will present our search for serendipitously observed asteroids in the data archive of the OSIRIS instrument on-board the ESA Rosetta mission.

  6. The Observing Working Group for the Asteroid Impact & Delfection Assessment (AIDA) Mission

    Science.gov (United States)

    Osip, David J.; Rivkin, Andrew S.; Pravec, Petr; Moskovitz, Nicholas; Thirouin, Audrey; Scheirich, Peter; Oszkiewicz, Dagmara Anna; Richardson, Derek C.; Polishook, David; Ryan, William; Thomas, Cristina; Busch, Michael W.; Cheng, Andrew F.; Michel, Patrick; AIDA Observing Working Group

    2016-10-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint ESA-NASA mission concept currently under study. AIDA has two components: the Double Asteroid Redirect Test (DART) is the US component designed to demonstrate a kinetic impactor, while the Asteroid Impact Mission (AIM) spacecraft is on station to do a thorough pre- and post-impact survey of the Didymos system.Members of the DART and AIM Investigation teams have been organized into several joint and independent working groups. While there is overlap in subject matter and membership between the groups, we focus here on the activities of the Observing Working Group.The first work by the group was undertaken during the spring of 2015, before DART entered Phase A. During this period Didymos made an apparition reaching roughly V ~ 20.5 in brightness, and our top priority was constraining which of two very different pole positions for the Didymos system was correct. Several telescopes in the 2-4-m aperture range around the world attempted observations. An observed mutual event allowed the one pole position to be ruled out. Didymos is now thought to be a low-obliquity, retrograde rotator, similar to many other asteroid binary systems and consistent with expectations from a YORP-driven origin for the satellite.We have begun planning for the 2017 apparition, occurring in the first half of the year. Didymos will be ~20% brighter at opposition than the 2015 apparition. Scaling from the successful observations with the 4.3-m Lowell Discovery Channel Telescope indicates that we will need telescopes at least 4 m (or larger, for some of the tasks, or at times longer before or after the opposition) in primary diameter for the advanced characterization in 2017.Currently, we have four goals for this apparition: 1) confirming the preferred retrograde pole position; 2) gathering data to allow BYORP-driven changes in the mutual orbit to potentially be determined by later observations; 3) establishing whether or not the

  7. Application of a Novel Long-Reach Manipulator Concept to Asteroid Redirect Missions

    Science.gov (United States)

    Dorsey, John T.; Doggett, William R.; Jones, Thomas C.; King, Bruce D.

    2015-01-01

    A high priority mission currently being formulated by NASA is to capture all or part of an asteroid and return it to cis-lunar space for examination by an astronaut crew. Two major mission architectures are currently being considered: in the first (Mission Concept A), a spacecraft would rendezvous and capture an entire free flying asteroid (up to 14 meters in diameter), and in the second (Mission Concept B), a spacecraft would rendezvous with a large asteroid (which could include one of the Martian moons) and retrieve a boulder (up to 4 meters in diameter). A critical element of the mission is the system that will capture the asteroid or boulder material, enclose it and secure it for the return flight. This paper describes the design concepts, concept of operations, structural sizing and masses of capture systems that are based on a new and novel Tendon- Actuated Lightweight In-Space MANipulator (TALISMAN) general-purpose robotic system. Features of the TALISMAN system are described and the status of its technology development is summarized. TALISMAN-based asteroid material retrieval system concepts and concepts-of-operations are defined for each asteroid mission architecture. The TALISMAN-based capture systems are shown to dramatically increase operational versatility while reducing mission risk. Total masses of TALISMAN-based systems are presented, reinforcing the mission viability of using a manipulator-based approach for the asteroid redirect mission.

  8. A Survey on Current Practice of Management of Early Onset Neonatal Sepsis.

    Science.gov (United States)

    Dey, A C; Hossain, M I; Afroze, S; Dey, S K; Mannan, M A; Shahidullah, M

    2016-04-01

    It was a survey type of cross sectional study where the participants were from different teaching/referral hospital across the country and was done to gather information regarding current practice of management of neonatal sepsis among paediatricians and neonatologists and was conducted on the spot during a national conference of Bangladesh Perinatal Society in December 2013. Specialists in neonatology, paediatrics, and some other disciplines working in different institutes across the country were requested to respond. Out of 150 physicians, 92 (61.33%) were neonatologists. Physicians suspected early onset neonatal sepsis (EONS) when there is history suggestive of prolonged rupture of membrane (74.77%), prolonged labour (9.33%), chorioamnionitis (7.33%) and maternal fever (2%). Clinical sepsis is found commonly (53.33%) which is later proved by laboratory evidences such as Hb%, TC, DC PBF (peripheral blood film), C-reactive protein, chest X-ray etc. Injection Ampicillin and Gentamycin are still the first choice of antibiotics (61.3%). Preferred route was intravenous (95.3%). Antibiotics were given for 7-10 days by most of the physicians (48.77%). However there is lack of uniformity among the participants in regard to taking decision about antibiotics, the choice of first line and the subsequent options of antibiotics. So, neonatal sepsis is the most important cause of neonatal mortality in the community. Therefore a standard protocolized approach for diagnosis and management of Early Onset Neonatal Sepsis may prove critical which is currently not in practice uniformly.

  9. Continuing professional development and Irish hospital doctors: a survey of current use and future needs.

    Science.gov (United States)

    Maher, Bridget; Faruqui, Adnan; Horgan, Mary; Bergin, Colm; Tuathaigh, Colm O; Bennett, Deirdre

    2017-07-01

    Doctors rate clinical relevance and applicability as the most important determinants of continuing professional development (CPD) course selection. This study examined patterns of current CPD practice and perceived CPD needs among hospital doctors in Ireland across various clinical specialties. A cross-sectional survey was administered to doctors, focusing on the areas of training needs analysis, CPD course content and preferred course format. In total, 547 doctors identified doctor-patient communication as the skill ranked highest for importance and level of current performance. Workload/time organisation and stress management were areas where a skills deficiency was identified. Non-clinical CPD topics, including resilience training, management and communication skills, were preferred areas for future CPD offerings. All respondents favoured interactive, hands-on sessions. CPD course completion and preference patterns differed significantly across clinical specialties. These results highlight the importance of considering the individual needs and preferences of clinicians across clinical specialties to facilitate more effective CPD programmes. © Royal College of Physicians 2017. All rights reserved.

  10. Familial determinants of current smoking among adolescents of Lithuania: a cross-sectional survey 2014.

    Science.gov (United States)

    Zaborskis, Apolinaras; Sirvyte, Dainora

    2015-09-14

    Understanding the role of the family in shaping adolescent health risk behaviours has recently been given increased attention. This study investigated association between current smoking and a range of familial factors in a representative sample of Lithuanian adolescents. Study subjects (N = 3696) were adolescents aged 13- and 15-years from the schools in Lithuania who were surveyed in Spring 2014 according to the methodology of the cross-national Health Behaviour in School-aged Children (HBSC). A standard HBSC international questionnaire was translated into Lithuanian and used anonymously to obtain information about current smoking patterns and family life (family structure, quality of communication in family, parental monitoring, bonding, parenting style, family time, etc.). Logistic regression was used to assess association between smoking and familial variables. The prevalence of current smoking was 16.5 % (20.8 % in boys and 11.9 % in girls; P satisfaction with family relationships (OR = 1.89; 95 % CI: 1.27-2.83), low school-related parental support (OR = 1.40; 95 % CI: 1.01-1.95), easy communication with the father (OR = 0.56; 95 % CI: 0.38-0.80) and often use of electronic media for communication with parents (OR = 0.66; 95 % CI: 0.50-0.88). The last two determinants showed an inverse effect than it was hypothesized. Higher prevalence of smoking among adolescents of Lithuania is associated with a non- intact family structure as well as weaker parental support and bonding. Family life practices are critical components to be incorporated in prevention and intervention programs for adolescent smoking in Lithuania.

  11. Basalt here, basalt there: Constraining the basaltic nature of eight Vp-type asteroids in the inner and outer main asteroid belt

    Science.gov (United States)

    Hardersen, Paul Scott; Reddy, Vishnu

    2016-10-01

    The distribution and abundance of basaltic material in the main asteroid belt has multiple implications that impact our understanding of the physical and thermal conditions that existed in the inner solar system during the formation epoch about 4.6 Gyr ago. Subjects impacted by a more accurate basaltic asteroid inventory include the efficacy of current inner solar system heating model predictions (Al-26 and T Tauri induction heating), the existence of differentiated parent bodies other than (4) Vesta, the dispersion efficiency of Vestoids by YORP forces, and the predictive ability of the V-taxonomy in predicting a basaltic surface composition. This work reports on a continuation of an effort to better constrain the basaltic asteroid population in the main asteroid belt with the goal of observing about 650 Vp-type asteroids. This work focuses on two populations: a) those Vp-classified asteroids (Carvano et al., 2010) in the spatial vicinity of (4) Vesta (candidate Vestoids) in the inner main belt, and b) Vp-classified asteroids in the outer main belt beyond 2.5 AU. Thus far, 23 Vp-type asteroids and candidate Vestoids have been observed and analyzed, which are all strongly suggestive of a basaltic surface composition (Hardersen et al., 2014, 2015, 2016 (in preparation)). However, unpublished work is beginning to show that the Vp taxonomic class is less accurate in its ability to identify basaltic surface compositions in outer-belt Vp-type asteroids. We report here on an additional set of Vp-type asteroids that were observed at the NASA Infrared Telescope Facility (IRTF) in December 2015 and January 2016. All observations were obtained with the SpeX spectrograph in prism mode with spectral range from 0.7 to 2.5 microns. They include (4900) Maymelou, (7302) 1993 CQ, (9064) Johndavies, (9531) Jean-Luc, (11341) Babbage, (17480) 1991 PE10, (20171) 1996 WC2, and (25849) 2000 ET107. We present average near-infrared (NIR) reflectance spectra of each asteroid, determine the

  12. The Potential of AutoClass as an Asteroidal Data Mining Tool

    Science.gov (United States)

    Walker, Matthew; Ziffer, J.; Harvell, T.; Fernandez, Y. R.; Campins, H.

    2011-05-01

    AutoClass-C, an artificial intelligence program designed to classify large data sets, was developed by NASA to classify stars based upon their infrared colors. Wanting to investigate its ability to classify asteroidal data, we conducted a preliminary test to determine if it could accurately reproduce the Tholen taxonomy using the data from the Eight Color Asteroid Survey (ECAS). For our initial test, we limited ourselves to those asteroids belonging to S, C, or X classes, and to asteroids with a color difference error of less than +/- 0.05 magnitudes. Of those 406 asteroids, AutoClass was able to confidently classify 85%: identifying the remaining asteroids as belonging to more than one class. Of the 346 asteroids that AutoClass classified, all but 3 (limiting the asteroids to those that had also been observed and classified in the Bus taxonomy. Of those 258 objects, AutoClass was able to classify 248 with greater than 75% certainty, and ranked albedo, not color, as the most influential factor. Interestingly, AutoClass consistently put P type objects in with the C class (there were 19 P types and 7 X types mixed in with the other 154 C types), and omitted P types from the group associated with the other X types (which had only one rogue B type in with its other 49 X-types). Autoclass classified the remaining classes with a high accuracy: placing one A and one CU type in with an otherwise perfect S group; placing three P type and one T type in an otherwise perfect D group; and placing the four remaining asteroids (V, A, R, and Q) into a class together.

  13. Albedo Properties of Small (0.5 to 20 km) Main Belt Asteroids

    Science.gov (United States)

    Ryan, Erin L.; Woodward, C. E.

    2010-01-01

    Serendipitous observations of main belt asteroids by the Spitzer Space Telescope have enabled determination of main belt asteroid albedos and diameters for targets as small as 0.5 km (eg., Ryan et al. 2009, AJ, 137, 5134). We have used multi-epoch data at 5.8, 8.0 and 24 microns from the MIPSGAL and Taurus Legacy Surveys to obtain diameters and albedos for a sample of approximately 2000 main belt asteroids. Using STM and NEATM, we have obtained diameters ranging from 0.5 to 30 km and albedos ranging from 0.02 to 0.5. Results of this program reveal an albedo distribution that is more diverse in range than the albedo distribution seen in the IRAS and MSX surveys. This diversity may reflect effects of space weathering reddening which is selectively reddening larger asteroids. This reddening effect may reinforce the findings from accretion models that indicate that asteroids in the early solar system were 100 km and larger (Morbidelli et al., 2009, Icarus, in press), by suggesting that the larger asteroids are indeed the oldest members of the main belt. We will present results on the albedo distribution as a function of semi-major axis and new analysis of the mean albedo of dynamical families within the main belt. Support for this work provided in part by a National Science Foundation grant AST-0706980 to the University of Minnesota.

  14. Asteroid Spin-Rate Study using the Intermediate Palomar Transient Factory

    CERN Document Server

    Chang, Chan-Kao; Lin, Hsing-Wen; Cheng, Yu-Chi; Ngeow, Chow-Choong; Yang, Ting-Chang; Waszczak, Adam; Kulkarni, Shrinivas R; Levitan, David; Sesar, Branimir; Laher, Russ; Surace, Jason; Prince, Thomas A

    2015-01-01

    Two dedicated asteroid rotation-period surveys have been carried out using data taken on January 6-9 and February 20-23 of 2014 by the Intermediate Palomar Transient Factory (iPTF) in the $R$~band with $\\sim 20$-min cadence. The total survey area covered 174~deg$^2$ in the ecliptic plane. Reliable rotation periods for 1,438 asteroids are obtained from a larger data set of 6,551 mostly main-belt asteroids, each with $\\geq 10$~detections. Analysis of 1751, PTF based, reliable rotation periods clearly shows the "spin barrier" at $\\sim 2$~hours for "rubble-pile" asteroids. We also found a new large-sized super-fast rotator, 2005 UW163 (Chang et al., 2014), and other five candidates as well. Our spin-rate distributions of asteroids with $3 < D < 15$~km shows number decrease when frequency greater than 5 rev/day, which is consistent to that of the Asteroid Light Curve Database (LCDB, Warner et al., 2009) and the result of (Masiero et al., 2009). We found the discrepancy in the spin-rate distribution between o...

  15. Distribution of spin-axes longitudes and shape elongations of main-belt asteroids

    CERN Document Server

    Cibulková, Helena; Vokrouhlický, David; Kaasalainen, Mikko; Oszkiewicz, Dagmara A

    2016-01-01

    Context: Large all-sky surveys provide us with a lot of photometric data that are sparse in time (typically few measurements per night) and can be potentially used for the determination of shapes and rotational states of asteroids. The method which is generally used to derive these parameters is the lightcurve inversion. However, for most asteroids their sparse data are not accurate enough to derive a unique model and the lightcurve inversion method is thus not very efficient. Aims: To fully utilize photometry sparse in time, we developed a new simplified model and applied it on the data from the Lowell photometric database. Our aim was to derive spin axis orientations and shape elongations of asteroids and to reconstruct distributions of these parameters for selected subpopulations to find if there are some differences. Methods: We model asteroids as geometrically scattering triaxial ellipsoids. Observed values of mean brightness and the dispersion of brightness are compared with computed values obtained fro...

  16. Asteroid family identification using the Hierarchical Clustering Method and WISE/NEOWISE physical properties

    CERN Document Server

    Masiero, Joseph R; Bauer, J M; Grav, T; Nugent, C R; Stevenson, R

    2013-01-01

    Using albedos from WISE/NEOWISE to separate distinct albedo groups within the Main Belt asteroids, we apply the Hierarchical Clustering Method to these subpopulations and identify dynamically associated clusters of asteroids. While this survey is limited to the ~35% of known Main Belt asteroids that were detected by NEOWISE, we present the families linked from these objects as higher confidence associations than can be obtained from dynamical linking alone. We find that over one-third of the observed population of the Main Belt is represented in the high-confidence cores of dynamical families. The albedo distribution of family members differs significantly from the albedo distribution of background objects in the same region of the Main Belt, however interpretation of this effect is complicated by the incomplete identification of lower-confidence family members. In total we link 38,298 asteroids into 76 distinct families. This work represents a critical step necessary to debias the albedo and size distributio...

  17. Detection of Large Color Variation of Potentially Hazardous Asteroid (297274) 1996 SK

    CERN Document Server

    Lin, Chien-Hsien; Lin, Zhong-Yi; Yoshida, Fumi; Cheng, Yu-Chi

    2013-01-01

    Low-inclination Near-Earth Asteroid (297274) 1996 SK, which is also classified as a Potentially Hazardous Asteroid, has a highly eccentric orbit. It was studied by multi-wavelength photometry within the framework of an NEA color survey at the Lulin Observatory. We report here the finding of large color variation across the surface of (297274) 1996 SK within one asteroidal rotation period of $4.656\\pm0.122$ hours and classify it as a S-type asteroid according to its average colors of $B-V=0.767\\pm0.033$, $V-R=0.482\\pm0.021$, $V-I=0.801\\pm0.025$ and the corresponding relative reflectance spectrum. It might be indicative of differential space weathering effect or compositional inhomogeneity of the surface materials.

  18. The current status of endoscopy in transsphenoidal surgery: an international survey.

    Science.gov (United States)

    de Divitiis, Enrico; Laws, Edward R; Giani, Umberto; Iuliano, Sherry L; de Divitiis, Oreste; Apuzzo, Michael L J

    2015-04-01

    A survey-based study was designed to assess opinions related to transsphenoidal endoscopy, to evaluate the current global attitudes of neurosurgeons regarding the use of this procedure, and to solicit basic data from key institutions worldwide, with the advantage that large series of cases become available for analysis. A web-based multi-item questionnaire was distributed to the surgical departments of 393 neurosurgical centers by means of an invitation e-mail. The questionnaire was composed of 2 sections: section 1 focused on the surgical technique for pituitary adenomas (standard technique), and section 2 concentrated on surgery for skull base tumors (extended technique). Each section was composed of 2 parts: multiple choice questions and free textual responses. From a total of 393 neurosurgical centers, from 23 countries, that received the questionnaire, 87 of them (22%) submitted complete or incomplete responses. The surgical procedure, in 60 cases had been performed by a neurosurgeon, in 53 cases by a neurosurgeon and an otolaryngologist, and in 4 cases by an otolaryngologist only. The endoscope (2- and 3-dimensional) was used in 85.2% of transsphenoidal procedures versus the microscope in 14.8% of cases. The endonasal route was used for approach in 93.2% versus the sublabial route in 6.8% of cases. Computer-guided navigation was used by survey population in 71 cases, micro-Doppler in 51 cases, and Cavitron Ultrasonic Surgical Aspirator in 43 cases. Several hundreds of extrasellar tumors were operated using the extended technique. Transsphenoidal endoscopy for pituitary and anterior skull base tumors has become established as a routine method of dealing with a variety of lesions. The level of interest in the neurosurgical surgery community is reflected by the geometric expansion of contributions to the literature on endoscopic surgery. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Current medication choices in juvenile rheumatoid arthritis II--update of a survey performed in 1993.

    Science.gov (United States)

    Brunner, H I; Kim, K N; Ballinger, S H; Bowyer, S L; Griffin, T A; Higgins, G C; Mier, R; Passo, M H; Rennebohm, R; Schikler, K; Lovell, D J

    2001-10-01

    The documentation of treatments used for Juvenile Rheumatoid Arthritis (JRA) is important to allow for the evaluation of practice patterns for future outcome studies. A survey of nine pediatric rheumatologists was performed between September 1999 and February 2000. Each of the physicians prospectively recorded demographic and treatment information on consecutively sampled JRA patients (n=395). Pauciarticular onset JRA was present in 46%, polyarticular onset JRA in 35%, and systemic onset JRA in 19% of the children. Naproxen was the most frequently prescribed medication (55% of the patients), followed by methotrexate (MTX), which was used in 39% of the patients. Folic acid supplementation (1 mg/day) was provided to 69% of the patients treated with MTX. Etanercept was used in 11% of the children. Eleven percent of the patients received corticosteroids, and 13% of children on corticosteroids took calcium supplements. Uveitis was present in 8% and had a chronic course in 79% of those cases. Although systemic medications were used in 50% of the children with uveitis to control eye inflammation, severe damage to the eyes developed in 30% of them. Fourteen percent of the patients required gastroprotective medications. Compared with findings of a similar survey performed in 1993, there was no significant change in the frequency of use of naproxen, but nabumetone is now more often prescribed, and COX-2 inhibitors have been introduced in the therapy of JRA. Changes among second-line agents used for JRA have also occurred, although there was no change in the frequency of use of MTX or corticosteroids. JRA continues to be a treatment challenge for the practicing pediatric rheumatologist. Patients often show incomplete response to the currently available medications. Therefore, new therapeutic agents need to be evaluated for their use in JRA, and the treatment of JRA associated uveitis especially needs to be improved.

  20. Using the Medicare Current Beneficiary Survey to conduct research on Medicare-eligible veterans

    Directory of Open Access Journals (Sweden)

    Yvonne Jonk, PhD

    2010-10-01

    Full Text Available The Medicare Current Beneficiary Survey (MCBS is a longitudinal, multipurpose panel survey of a nationally representative sample of Medicare beneficiaries sponsored by the Centers for Medicare and Medicaid Services (CMS. The MCBS serves as a comprehensive data source on self-reported health and socioeconomic status, health insurance, healthcare utilization and costs, and patient satisfaction. CMS uses Medicare claims data to validate self-reported Medicare Fee-For-Service (FFS utilization. Because the Veterans Health Administration (VHA does not bill for services, CMS imputes VHA costs. This article addresses the quality of the MCBS dataset for conducting research on Medicare-eligible veterans by addressing the sample's representativeness, quality of self-reported data, and accuracy of imputed VHA cost estimates. We compared demographic data from the 1992 and 2001 National Survey of Veterans (NSV with the MCBS 1992 and 2001 Cost and Use files. We compared self-reported VHA utilization and CMS's imputed costs with VHA administrative datasets. The VHA's Pharmacy Benefits Management (PBM database is available from fiscal year (FY 1999 onward, and the VHA Health Economics Resource Center's (HERC Average Cost datasets are available from FY1998 onward. While the samples were comparable in terms of age, sex, and race, the MCBS respondents were in better health, less likely to be married, and more likely to be widowed than NSV respondents. MCBS underreporting rates were higher for VHA than Medicare outpatient events. Underreporting and differences between CMS's and HERC's costing methodologies contributed to lower MCBS versus VHA administrative person- and event- level costs. Alternatively, average annual VHA prescription costs per capita were higher in the MCBS than in the PBM data. Differences in socioeconomic characteristics of the NSV and MCBS samples may be attributable to differences in sampling methodologies. Higher underreporting rates for VHA

  1. The young Datura asteroid family. Spins, shapes, and population estimate

    Science.gov (United States)

    Vokrouhlický, D.; Pravec, P.; Durech, J.; Bolin, B.; Jedicke, R.; Kušnirák, P.; Galád, A.; Hornoch, K.; Kryszczyńska, A.; Colas, F.; Moskovitz, N.; Thirouin, A.; Nesvorný, D.

    2017-02-01

    Context. Asteroid families are the outcomes of disruption or cratering events on a size and energy scales that are not reproducible in laboratory experiments. Overall structure, as well as properties of individual members, in the old families could have been changed since their formation. Therefore young families preserve best the characteristics of the initial event. Aims: We study the most suitable known asteroid family with an age of less than 1 Myr, the Datura family. We aim (i) to obtain information about rotation state and shape of the largest members in the family; and (ii) to constrain its debiased population down to couple of hundreds of meters in size. Methods: We have analyzed the up-to-date catalog of orbital elements of main belt asteroids. We evaluated the detection efficiency of Catalina Sky Survey (CSS) in regard to detections of members in the Datura family, and we have used our photometric observations and lightcurve inversion methods to determine the rotation states and shapes of the largest members of the family. Results: We determined rotation periods of the seven largest members of the Datura family, and we also derived accurate mean absolute magnitudes for six of them. Except for the largest fragment (1270) Datura, the asteroids tend to have long rotation periods and large amplitude of the lightcurve, witnessing an elongated shape. For the four largest asteroids, our observations allow us to resolve rotation pole and a rough shape. All of them are prograde-rotating and have the latitude of the rotation pole >50°. Our search in orbital catalogs resulted in the discovery of many small, sub-kilometer members of the Datura family. Using the CSS detection efficiency, we inverted this information into the debiased population of Datura family members. We show that the mass and angular momentum content in small fragments is negligible compared to the largest fragment (1270) Datura. These findings may help to constrain the formation mechanism of the

  2. Asteroid magnitudes, UBV colors, and IRAS albedos and diameters

    Science.gov (United States)

    Tedesco, Edward F.

    1989-01-01

    This paper lists absolute magnitudes and slope parameters for known asteroids numbered through 3318. The values presented are those used in reducing asteroid IR flux data obtained with the IRAS. U-B colors are given for 938 asteroids, and B-V colors are given for 945 asteroids. The IRAS albedos and diameters are tabulated for 1790 asteroids.

  3. Asteroid exploration and utilization: The Hawking explorer

    Science.gov (United States)

    Carlson, Alan; Date, Medha; Duarte, Manny; Erian, Neil; Gafka, George; Kappler, Peter; Patano, Scott; Perez, Martin; Ponce, Edgar; Radovich, Brian

    1991-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources which may exist on asteroids could have enormous potential for aiding and enhancing human space exploration as well as life on Earth. With the possibly limitless opportunities that exist, it is clear that asteroids are the next step for human existence in space. This report comprises the efforts of NEW WORLDS, Inc. to develop a comprehensive design for an asteroid exploration/sample return mission. This mission is a precursor to proof-of-concept missions that will investigate the validity of mining and materials processing on an asteroid. Project STONER (Systematic Transfer of Near Earth Resources) is based on two utilization scenarios: (1) moving an asteroid to an advantageous location for use by Earth; and (2) mining an asteroids and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plane for humans to utilize asteroid resources. The report concentrates specifically on the selection of the most promising asteroids for exploration and the development of an exploration scenario. Future utilization as well as subsystem requirements of an asteroid sample return probe are also addressed.

  4. 76 FR 39260 - Direct Investment Surveys: Alignment of Regulations With Current Practices

    Science.gov (United States)

    2011-07-06

    ... is eliminating the reporting requirements for two surveys of new foreign direct investment in the... several direct investment surveys. The surveys are: BE-13, Initial Report on a Foreign Person's Direct or... to measure the amount of new foreign direct investment in the United States and assess its impact...

  5. The Asteroid 1998 QE2

    Science.gov (United States)

    Vodniza, Alberto Q.; Pereira, M. R.; Arecibo Observatory Team; JPL Target Asteroids Team

    2013-10-01

    This big asteroid was at 5.8 millions of kilometers from the Earth on May 31 (2013) and it has a diameter of 2.7 km. The radar images obtained by JPL showed that the period of rotation around its axis is close to five hours. Hills. K (2013) reported that the period is of 5.281 +/- 0.002 hours. On June 4 the team of Goldstone-Arecibo found a period of 4.75 +/- 0.01 hours. We also contributed with the light and phase curves to estimate the period by means of the telescope (with red filter). The radar imagery (JPL and Arecibo) revealed that 1998 QE2 has a moon, and we captured a mutual event (eclipse). From our Observatory, located in Pasto-Colombia, we captured several pictures, videos and astrometry data during several days. Our data was published by the Minor Planet Center (MPC) and also appears at the web page of NEODyS. The pictures of the asteroid were captured with the following equipment: CGE PRO 1400 CELESTRON (f/11 Schmidt-Cassegrain Telescope) and STL-1001 SBIG camera. We obtained the light curve of the body. Astrometry was carried out, and we calculated the orbital elements. We obtained the following orbital parameters: eccentricity = 0.5692181, semi-major axis = 2.41104631 A.U, orbital inclination = 12.82771 deg, longitude of the ascending node = 250.16876 deg, argument of perihelion = 345.61328 deg, mean motion = 0.26326658 deg/d, perihelion distance = 1.03863508 A.U, aphelion distance = 3.78345755 A.U. The asteroid has an orbital period of 3.74 years The parameters were calculated based on 191 observations (2013 May: 17-24) with mean residual = 0.162 arcseconds. A video of the asteroid from our Observatory was published on the main page of the “SPACEWEATHER” web: http://www.spaceweather.com/archive.php?view=1&day=21&month=05&year=2013 Note: The autors would like to thank to: Dr. Alessondra Springmann (Arecibo Observatory), Dr. Petr Pravec (Czech Republic), Dr. Lance Benner (JPL), Dr. Carl Hergenrother (Target Asteroids Team), and Dr. Dolores Hill

  6. Moving an asteroid with electric solar wind sail

    Science.gov (United States)

    Merikallio, S.; Janhunen, P.

    2010-12-01

    The electric solar wind sail (E-Sail) is a new propulsion method for interplanetary travel which was invented in 2006 and is currently under development. The E-Sail uses charged tethers to extract momentum from the solar wind particles to obtain propulsive thrust. According to current estimates, the E-Sail is 2-3 orders of magnitude better than traditional propulsion methods (chemical rockets and ion engines) in terms of produced lifetime-integrated impulse per propulsion system mass. Here we analyze the problem of using the E-Sail for directly deflecting an Earth-threatening asteroid. The problem then culminates into how to attach the E-Sail device to the asteroid. We assess alternative attachment strategies, namely straightforward direct towing with a cable and the gravity tractor method which works for a wider variety of situations. We also consider possible techniques to scale up the E-Sail force beyond the baseline one Newton level to deal with more imminent or larger asteroid or cometary threats. As a baseline case we consider an asteroid of effective diameter of 140 m and mass of 3 million tons, which can be deflected with a baseline 1 N E-Sail within 10 years. With a 5 N E-Sail the deflection could be achieved in 5 years. Once developed, the E-Sail would appear to provide a safe and reasonably low-cost way of deflecting dangerous asteroids and other heavenly bodies in cases where the collision threat becomes known several years in advance.

  7. A mission concept for a Grand Tour of Multiple Asteroid Systems

    Science.gov (United States)

    Marchis, F.; Dankanich, J.; Tricarico, P.; Bellerose, J.

    2009-12-01

    In 1993, the Galileo spacecraft imaged the first companion of asteroid, Dactyl orbiting 243 Ida, a main-belt asteroid. Since then, discoveries have been accumulated thanks to the development of high angular resolution imaging on ground-based telescopes (adaptive optics), radar observations and accurate photometric light curve measurements. To date, 180 companions of small solar system bodies (SSSBs) are known in various populations, including 100 in the asteroid main belt, 33 Near Earth Asteroids, 4 Jupiter-Trojan asteroids and 44 in the Kuiper Belt. Multiple Asteroids have been shown to be complex worlds in their own with a wide range of morphologies, dynamical histories, and structural evolution. To the exception of 243 Ida, no spacecraft has visited any of them. Investigating binary asteroid systems can verify and validate current theories on their formation and on the influence of the sun in their formation (YORP effect) and evolution (space weathering). In particular, assessing the origin of the secondary satellite, if it is of common origin or capture, can provide clue of their formation. To a larger extend, the determination of their nature, scenario formation and evolution are key to understand how planet formation occurred but also to understand i) the population and compositional structure of the SSSB today ii) how the dynamics and collisions modify this structure over time iii) what the physical properties of asteroids are (density, porosity) iv) how the surface modification processes affect our ability to determine this structure (e.g. space weathering). In addition, being able to study these properties on closeby asteroids will give a relative scale accounting for the sizes, shape, rotation periods and cratering rate of these small and young bodies. In the framework of the NASA Discovery program, we propose a mission consisting of a Grand Tour of several multiple asteroid systems, including the flyby of a near earth binary asteroid and the rendezvous

  8. Yarkovsky V-shape identification of asteroid families

    Science.gov (United States)

    Bolin, Bryce T.; Delbo, Marco; Morbidelli, Alessandro; Walsh, Kevin J.

    2016-10-01

    There are only a few known main belt (MB) asteroid families with ages greater than 2 Gyrs. Estimates based on the family producing collision rate suggest that the lack of >2 Gyr-old families may be due to a selection bias in current techniques used to identify families. Family fragments disperse in their orbital elements, semi-major axis, a, eccentricity, e and inclination, i due to secular resonances, close encounters with massive asteroids and the non-gravitational Yarkovsky force. This causes the family fragments to be indistinguishable from the background of the main belt making them more difficult to identify with the hierarchical clustering method (HCM) with increasing family age. The discovery of the Eulalia and Polana families in the inner belt relied on new techniques because they were overlapping families, also, or primarily, because Yarkovsky spreading over their 2 Gyr-old lifetime made them too disperse to be identified using the classical HCM. The techniques used to discover the Polana and Eulalia are modified here to identify asteroid families by searching for correlations between a and absolute magnitude, H, the family's characteristic V-shape. In addition to demonstrating the V-shape technique on known families such as Erigone, Vesta, Flora and Polana, we will present a new investigation of the asteroid belt with this new tool looking for old, previously unidentified families.

  9. A Survey on Renewable Energy Development in Malaysia: Current Status, Problems and Prospects

    Directory of Open Access Journals (Sweden)

    Alam Syed Shah

    2016-05-01

    Full Text Available Energy demand in Malaysia is increasing over seven per cent a year, while forty per cent of the energy is supplied from conventional fossil fuel. However, a number of social barriers have mired the social acceptance of renewable energy among the users. This study investigates the current status of renewable energy, problems and future outlook of renewable energy in Malaysia. A total of 200 respondents were surveyed from Klang Valley in Malaysia. Majority of the respondents use energy to generate electricity. Although some respondents reported using solar energy, there is lack of retail availability for solar energy. The findings show that limited information on renewable energy technologies, lack of awareness, and limited private sector engagement emerged as major barriers to sustainable renewable energy development. In addition, the respondents suggest for increasing policy support from the government to make information more accessible to mass users, provide economic incentives to investors and users, and promote small-community based renewable energy projects. The study suggests that the government begin small scale projects to build awareness on renewable energy, while academically, higher learning institutions include renewable energy syllabus in their academic curriculum. The study concluded that to have sustainable renewable energy development, government’s initiative, private sector engagement and users awareness must be given priority.

  10. Current practices in percutaneous nephrolithotomy in Mexico: results of a nation-wide electronic survey.

    Science.gov (United States)

    Sandoval, Christian I Villeda; Roca, Benjamin E Montaño; Molina, Ricardo A Castillejos; Mendez-Probst, Carlos E

    2015-11-01

    Practice patterns and choice of technological instruments in PCNL are not always standardized. There are no previous reports on the PCNL practice tendencies and patterns in Latin America. The aim of the study is to describe the current practice patterns of PCNL among the members of the Mexican Society of Urology ("Sociedad Mexicana de Urologia"). Observational and descriptive study. A 9-item closed questionnaire on PCNL practice patterns was answered by members of the Mexican Society of Urology in a secure website hosted survey after e-mail invitation. A descriptive numerical and graphical analysis was performed. A total of 90 contestants were registered out of 492 potential participants. PCNL is performed by 80% of the participants, with an average of 16 procedures per year. Percutaneous tracts are commonly obtained by urologists on the same day of the procedure. Sequential and telescopic dilators are equally preferred over balloons. The pneumatic litotriptor is the most common choice and CT scan and X-ray are equally used as follow-up. The practice patterns of PCNL from Mexican urologists are different from other international reports. Influence of socio-economic circumstances is inferred.

  11. A Survey on Renewable Energy Development in Malaysia: Current Status, Problems and Prospects

    Science.gov (United States)

    Alam, Syed Shah; Nor, Nor Fariza Mohd; Ahmad, Maisarah; Hashim, Nik Hazrul Nik

    2016-05-01

    Energy demand in Malaysia is increasing over seven per cent a year, while forty per cent of the energy is supplied from conventional fossil fuel. However, a number of social barriers have mired the social acceptance of renewable energy among the users. This study investigates the current status of renewable energy, problems and future outlook of renewable energy in Malaysia. A total of 200 respondents were surveyed from Klang Valley in Malaysia. Majority of the respondents use energy to generate electricity. Although some respondents reported using solar energy, there is lack of retail availability for solar energy. The findings show that limited information on renewable energy technologies, lack of awareness, and limited private sector engagement emerged as major barriers to sustainable renewable energy development. In addition, the respondents suggest for increasing policy support from the government to make information more accessible to mass users, provide economic incentives to investors and users, and promote small-community based renewable energy projects. The study suggests that the government begin small scale projects to build awareness on renewable energy, while academically, higher learning institutions include renewable energy syllabus in their academic curriculum. The study concluded that to have sustainable renewable energy development, government's initiative, private sector engagement and users awareness must be given priority.

  12. Current and future delivery of diagnostic electron microscopy in the UK: results of a national survey.

    Science.gov (United States)

    de Haro, Tracey; Furness, Peter

    2012-04-01

    Electron microscopy (EM) remains essential to delivering several specialist areas of diagnosis, especially the interpretation of native renal biopsies. However, there is anecdotal evidence of EM units struggling to survive, for a variety of reasons. The authors sought to obtain objective evidence of the extent and the causes of this problem. An online survey was undertaken of Fellows of the Royal College of Pathologists who use EM in diagnosis. A significant number of EM units anticipate having to close and hence outsource their EM work in the coming years. Yet most existing units are working to full capacity and would be unable to take on the substantial amounts of extra work implied by other units outsourcing their needs. Equipment and staffing are identified by most EM units as the major barriers to growth and are also the main reasons cited for units facing potential closure. In the current financial climate it seems unlikely that units will be willing to make the large investment in equipment and staff needed to take on extra work, unless they can be reasonably confident of an acceptable financial return as a result of increased external referral rates. The case is thus made for a degree of national coordination of the future provision of this specialist service, possibly through the National Commissioning Group or the new National Commissioning Board. Without this, the future of diagnostic EM services in the UK is uncertain. Its failure would pose a threat to good patient care.

  13. Laparoscopic simulation training in gynaecology: Current provision and staff attitudes - a cross-sectional survey.

    Science.gov (United States)

    Burden, Christy; Fox, Robert; Hinshaw, Kim; Draycott, Timothy J; James, Mark

    2016-01-01

    The objectives of this study were to explore current provision of laparoscopic simulation training, and to determine attitudes of trainers and trainees to the role of simulators in surgical training across the UK. An anonymous cross-sectional survey with cluster sampling was developed and circulated. All Royal College of Obstetricians and Gynaecologists (RCOG) Training Programme Directors (TPD), College Tutors (RCT) and Trainee representatives (TR) across the UK were invited to participate. One hundred and ninety-six obstetricians and gynaecologists participated. Sixty-three percent of hospitals had at least one box trainer, and 14.6% had least one virtual-reality simulator. Only 9.3% and 3.6% stated that trainees used a structured curriculum on box and virtual-reality simulators, respectively. Respondents working in a Large/Teaching hospital (p = 0.008) were more likely to agree that simulators enhance surgical training. Eighty-nine percent agreed that simulators improve the quality of training, and should be mandatory or desirable for junior trainees. Consultants (p = 0.003) and respondents over 40 years (p = 0.011) were more likely to hold that a simulation test should be undertaken before live operation. Our data demonstrated, therefore, that availability of laparoscopic simulators is inconsistent, with limited use of mandatory structured curricula. In contrast, both trainers and trainees recognise a need for greater use of laparoscopic simulation for surgical training.

  14. Regular Motions of Resonant Asteroids

    Science.gov (United States)

    Ferraz-Mello, S.

    1990-11-01

    RESUMEN. Se revisan resultados analiticos relativos a soluciones regulares del problema asteroidal eliptico promediados en la vecindad de una resonancia con jupiten Mencionamos Ia ley de estructura para libradores de alta excentricidad, la estabilidad de los centros de liberaci6n, las perturbaciones forzadas por la excentricidad de jupiter y las 6rbitas de corotaci6n. ABSTRAC This paper reviews analytical results concerning the regular solutions of the elliptic asteroidal problem averaged in the neighbourhood of a resonance with jupiter. We mention the law of structure for high-eccentricity librators, the stability of the libration centers, the perturbations forced by the eccentricity ofjupiter and the corotation orbits. Key words: ASThROIDS

  15. Colorimetry and magnitudes of asteroids

    Science.gov (United States)

    Bowell, E.; Lumme, K.

    1979-01-01

    In the present paper, 1500 UBV observations are analyzed by a new rather general multiple scattering theory which provided clear insight into previously poorly-recognized optical nature of asteroid surfaces. Thus, phase curves are shown to consist of a surface-texture controlled component, due to singly scattered light, and a component due to multiple scattering. Phase curve shapes can be characterized by a single parameter, the multiple scattering factor, Q. As Q increases, the relative importance of the opposition effect diminishes. Asteroid surfaces are particulate and strikingly similar to texture, being moderately porous and moderately rough on a scale greater than the wavelength of light. In concequence, Q (and also the phase coefficient) correlate well with geometric albedo, and there exists a purely photometric means of determining albedos and diameters.

  16. Comets and Asteroids with FIRST

    Science.gov (United States)

    Bockelée-Morvan, D.; Crovisier, J.

    2001-07-01

    The infrared and microwave domains have proved to be privileged tools to study the physical and chemical properties of small bodies of the Solar System. After a review of the recent results obtained on comets and asteroids in these wavelength ranges, we forecast the major outcomes that can be expected from their observations with the Herschel Space Observatory (hereafter referred as to FIRST, the former denomination). This prospect is focussed on: 1) observations of water rotational lines in comets to measure water outgassing and study water excitation in the coma and its kinematics; 2) observations of HDO in comets to constrain solar nebula models and formation scenarii of comets; 3) the study of surface properties of asteroids.

  17. A method to determine asteroid poles

    Science.gov (United States)

    Deangelis, G.

    1993-01-01

    The determination of spin axis and shape is well known to be of fundamental importance for studies about the rotational and physical properties of asteroids. In particular, knowledge that the pole coordinate distribution is random or not could indicate the probable non-Maxwellian distribution of asteroid spin axes, while the distribution in terms of size and shape could place important constraints on the theories about the collisional history of some individual asteroids, of asteroid families, and of the asteroid population as a whole. Many kinds of methods have been developed to determine pole coordinates. An EA method is presented, from which it is possible to obtain the solution with no trial poles, but with a simultaneous least square fit on both the E and A part. Results for rotational and shape parameters were obtained for 18 asteroids: the values of the obtained parameters are generally in close agreement with those of others.

  18. Eccentricity distribution in the main asteroid belt

    CERN Document Server

    Malhotra, Renu

    2016-01-01

    The observationally complete sample of the main belt asteroids now spans more than two orders of magnitude in size and numbers more than 64,000 (excluding collisional family members). We undertook an analysis of asteroids' eccentricities and their interpretation with simple physical models. We find that Plummer's (1916) conclusion that the asteroids' eccentricities follow a Rayleigh distribution holds for the osculating eccentricities of large asteroids, but the proper eccentricities deviate from a Rayleigh distribution: there is a deficit of eccentricities smaller than $\\sim0.1$ and an excess of larger eccentricities. We further find that the proper eccentricities do not depend significantly on asteroid size but have strong dependence on heliocentric distance: the outer asteroid belt follows a Rayleigh distribution, but the inner belt is strikingly different. Eccentricities in the inner belt can be modeled as a vector sum of a primordial eccentricity vector of random orientation and magnitude drawn from a Ra...

  19. Mining the Apollo and Amor asteroids

    Science.gov (United States)

    Oleary, B.

    1977-01-01

    Earth-approaching asteroids could provide raw materials for space manufacturing. For certain asteroids the total energy per unit mass for the transfer of asteroidal resources to a manufacturing site in high earth orbit is comparable to that for lunar materials. For logistical reasons the cost may be many times less. Optical studies suggest that these asteroids have compositions corresponding to those of carbonaceous and ordinary chondrites, with some containing large quantities of iron and nickel; other are thought to contain carbon, nitrogen, and hydrogen, elements that appear to be lacking on the moon. The prospect that several new candidate asteroids will be discovered over the next few years increases the likelihood that a variety of asteroidal resource materials can be retrieved on low-energy missions.

  20. Asteroids prospective energy and material resources

    CERN Document Server

    2013-01-01

    The Earth has limited material and energy resources while these resources in space are virtually unlimited. Further development of humanity will require going beyond our planet and exploring of extraterrestrial resources and sources of unlimited power.   Thus far, all missions to asteroids have been motivated by scientific exploration. However, given recent advancements in various space technologies, mining asteroids for resources is becoming ever more feasible. A significant portion of asteroids value is derived from their location; the required resources do not need to be lifted at a great expense from the surface of the Earth.   Resources derived from Asteroid not only can be brought back to Earth but could also be used to sustain human exploration of space and permanent settlements in space.   This book investigates asteroids' prospective energy and material resources. It is a collection of topics related to asteroid exploration, and utilization. It presents past and future technologies and solutions t...

  1. Exospheres from Asteroids to Planets

    Science.gov (United States)

    Killen, Rosemary M.; Burger, Matthew H.; Farrell, William M.; DREAM2

    2016-10-01

    The study of exospheres can help us understand the long-term loss of volatiles from planetary bodies due to interactions of planets, satellites, and small bodies with the interplanetary medium (solar wind, meteors, and dust), solar radiation, internal forces including diffusion and outgassing, and surface effects like sticking and chemistry. Recent evidence for water and OH on the moon has spurred interest in processes involving chemistry and sequestration of volatile species at the poles and in voids. In recent years, NASA has sent spacecraft to asteroids including Vesta and Ceres, and ESA sent Rosetta to the asteroids Lutetia and Steins. OSIRIS-REX will return a sample from a primitive asteroid, Bennu, to Earth. It is possible that a Phobos-Deimos flyby will be a precursor to a manned mission to Mars. Exospheric particles are derived from the surface and to some extent from interplanetary dust and meteoroids. By comparing the exospheric compositions before and after major meteor shower events it may be possible to determine the extent to which the exosphere reflects the surface composition. Observation of an escaping exosphere, termed a corona, is challenging. We therefore have embarked on a parametrical study of exospheres as a function of basic controlling parameters such as the mass of the primary object, mass of the exospheric species, heliocentric distance, rotation rate of the primary, composition of the body (asteroid type or icy body). These parameters will be useful for mission planning as well as quick look data to determine the size and location of bodies likely to retain their exospheres and observability of exospheric species. We will also consider the sizes of small clusters that may be gravitationally bound to small bodies such as Phobos. In addition, it is of interest to be able to determine the extent of contamination of the pristine exosphere due to the spacecraft sent to make measurements, and the effect on the measurements of outgassing in the

  2. Recovering and Mining Asteroids with a Gas-Sealed Enclosure

    Science.gov (United States)

    Jenniskens, P.; Damer, B.; Norkus, R.; Pilotz, S.; Grigsby, B.; Adams, C.; Blair, B. R.

    2015-01-01

    The internal structure of weakly consolidated rubble piles and primitive asteroids can be studied closer to home, and such asteroids can be mined, if it is possible to create a gas-sealed enclosure around the asteroid.

  3. Storyboard GALILEO CRUISE SCIENCE OPPORTUNITIES describes asteroid encounters

    Science.gov (United States)

    1989-01-01

    Storyboard with mosaicked image of an asteroid and entitled GALILEO CRUISE SCIENCE OPPORTUNITIES describes asteroid objectives. These objectives include: first asteroid encounter; surface geology, composition size, shape, mass; and relation of primitive bodies to meteorites.

  4. Anchoring a lander on an asteroid using foam stabilization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has proposed several missions to land a craft on an asteroid and potentially to return samples from it. While large asteroids in the asteroid belt can exhibit a...

  5. Stabilities of asteroid orbits in resonances

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A map of the asteroid motion is studied carefully. An exponential diffusion law in the chaotic sea and an algebraic law in the mixed region are observed. The effects of perturbations on diffusion are also discussed. The fixed points, their stabilities and the diffusion properties of the map give qualitative explanations of the distribution of asteroids, i.e. the depletion and accumulation of asteroids in the outer main belt, particularly in the first order mean motion resonances with Jupiter.

  6. Geotechnical Tests on Asteroid Simulant Orgueil

    Science.gov (United States)

    Garcia, Alexander D'marco

    2017-01-01

    In the last 100 years, the global population has more than quadrupled to over seven billion people. At the same time, the demand for food and standard of living has been increasing which has amplified the global water use by nearly eight times from approximately 500 to 4000 cu km per yr from 1900 to 2010. With the increasing concern to sustain the growing population on Earth it is necessary to seek other approaches to ensure that our planet will have resources for generations to come. In recent years, the advancement of space travel and technology has allowed the idea of mining asteroids with resources closer to becoming a reality. During the duration of the internship at NASA Kennedy Space Center, several geotechnical tests were conducted on BP-1 lunar simulant and asteroid simulant Orgueil. The tests that were conducted on BP-1 was to practice utilizing the equipment that will be used on the asteroid simulant and the data from those tests will be omitted from report. Understanding the soil mechanics of asteroid simulant Orgueil will help provide basis for future technological advances and prepare scientists for the conditions they may encounter when mining asteroids becomes reality in the distant future. Distinct tests were conducted to determine grain size distribution, unconsolidated density, and maximum density. Once the basic properties are known, the asteroid simulant will be altered to different levels of compaction using a vibrator table to see how compaction affects the density. After different intervals of vibration compaction, a miniature vane shear test will be conducted. Laboratory vane shear testing is a reliable tool to investigate strength anisotropy in the vertical and horizontal directions of a very soft to stiff saturated fine-grained clayey soil. This test will provide us with a rapid determination of the shear strength on the undisturbed compacted regolith. The results of these tests will shed light on how much torque is necessary to drill

  7. Overview and Updated Status of the Asteroid Redirect Mission (ARM)

    Science.gov (United States)

    Abell, Paul; Mazanek, Daniel D.; Reeves, David M.; Chodas, Paul; Gates, Michele; Johnson, Lindley N.; Ticker, Ronald

    2016-10-01

    The National Aeronautics and Space Administration (NASA) is developing a mission to visit a large near-Earth asteroid (NEA), collect a multi-ton boulder and regolith samples from its surface, demonstrate a planetary defense technique known as the enhanced gravity tractor, and return the asteroidal material to a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts will explore the boulder and return to Earth with samples. This Asteroid Redirect Mission (ARM) is part of NASA's plan to advance the technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s and other destinations, as well as provide other broader benefits. Subsequent human and robotic missions to the asteroidal material would also be facilitated by its return to cislunar space. Although ARM is primarily a capability demonstration mission (i.e., technologies and associated operations), there exist significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, asteroidal resources and in-situ resource utilization (ISRU), and capability and technology demonstrations. Current plans are for the robotic mission to be launched in late 2021 with the crewed mission segment conducted using an Orion capsule via a Space Launch System rocket in 2026. In order to maximize the knowledge return from the mission, NASA is providing accommodations for payloads to be carried on the robotic segment of the mission and also organizing an ARM Investigation Team. The Investigation Team will be comprised of scientists, technologists, and other qualified and interested individuals from US industry, government, academia, and international institutions to help plan the implementation and execution of ARM. The presentation will provide a mission overview and the most recent update concerning the robotic and crewed segments of ARM, including the mission requirements, and potential

  8. The current status of pediatric radiology in India: A conference-based survey

    Directory of Open Access Journals (Sweden)

    Jacob Therakathu

    2017-01-01

    Full Text Available Introduction: Like most other developing countries, India has a large proportion of children among its population. However, the facilities for adequate treatment of this large population is inadequate. The development of pediatric radiology as a subspecialty is still at an infant stage in India. The goal of our study was to assess the awareness about the current status of pediatric radiology in India. Materials and Methods: A questionnaire was handed over to all attendees of a pediatric radiology conference to assess their opinion regarding the adequacy of pediatric training and practice in India. The questionnaire consisted of 10 multiple-choice and two descriptive questions. Descriptive statistical methods were used for analyzing the results. Results: Eighty-one out of 400 delegates responded to the questionnaire. Among these 81 respondents, 50 (61.7% felt that exposure to pediatric cases during postgraduate course was inadequate. Sixty-three out of 81 (77.7% respondents thought that specialized training is required for practicing pediatric radiology, and 79 respondents (97% felt that the number of such training programmes should increase. Forty-five out of 81 respondents (55.5% were interested in pursuing pediatric radiology as a career. Conclusion: According to the opinion of the respondents of our survey, pediatric radiology remains an underdeveloped speciality in India. Considering the proportion of the population in the pediatric age and the poor health indicators in this age group, elaborate measures, as suggested, need to be implemented to improve pediatric radiology training and the care of sick children in India.

  9. A survey on IVIVC/IVIVR development in the pharmaceutical industry - Past experience and current perspectives.

    Science.gov (United States)

    Nguyen, M A; Flanagan, T; Brewster, M; Kesisoglou, F; Beato, S; Biewenga, J; Crison, J; Holm, R; Li, R; Mannaert, E; McAllister, M; Mueller-Zsigmondy, M; Muenster, U; Ojala, K; Page, S; Parr, A; Rossenu, S; Timmins, P; Van Peer, A; Vermeulen, A; Langguth, P

    2017-05-01

    of non-compendial dissolution methods for establishing a successful IVIVC/IVIVR. The lack of appropriate in vivo data and regulatory uncertainty were considered the major difficulties in IVIVC/IVIVR development. The results of this survey provide unique insights into current IVIVC/IVIVR practices in the pharmaceutical industry. Pursuing an IVIVC/IVIVR should be generally encouraged, considering its high value from both industry and regulators' perspective. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Test result communication in primary care: a survey of current practice.

    Science.gov (United States)

    Litchfield, Ian; Bentham, Louise; Lilford, Richard; McManus, Richard J; Hill, Ann; Greenfield, Sheila

    2015-11-01

    The number of blood tests ordered in primary care continues to increase and the timely and appropriate communication of results remains essential. However, the testing and result communication process includes a number of participants in a variety of settings and is both complicated to manage and vulnerable to human error. In the UK, guidelines for the process are absent and research in this area is surprisingly scarce; so before we can begin to address potential areas of weakness there is a need to more precisely understand the strengths and weaknesses of current systems used by general practices and testing facilities. We conducted a telephone survey of practices across England to determine the methods of managing the testing and result communication process. In order to gain insight into the perspectives from staff at a large hospital laboratory we conducted paired interviews with senior managers, which we used to inform a service blueprint demonstrating the interaction between practices and laboratories and identifying potential sources of delay and failure. Staff at 80% of practices reported that the default method for communicating normal results required patients to telephone the practice and 40% of practices required that patients also call for abnormal results. Over 80% had no fail-safe system for ensuring that results had been returned to the practice from laboratories; practices would otherwise only be aware that results were missing or delayed when patients requested results. Persistent sources of missing results were identified by laboratory staff and included sample handling, misidentification of samples and the inefficient system for collating and resending misdirected results. The success of the current system relies on patients both to retrieve results and in so doing alert staff to missing and delayed results. Practices appear slow to adopt available technological solutions despite their potential for reducing the impact of recurring errors in the

  11. DARe: Dark Asteroid Rendezvous

    Science.gov (United States)

    Noll, K. S.; McFadden, L. A.; Rhoden, A. R.; Lim, L. F.; Boynton, W. V.; Carter, L. M.; Collins, G.; Englander, J. A.; Goossens, S. A.; Grundy, W. M.; Li, J.-Y.; Mottola, S.; Oberst, J.; Orosei, R.; Parsons, A. M.; Preusker, F.; Reuter, D. C.; Simon, A. A.; Thomas, C. A.; Walsh, K.; Zolensky, M. E.

    2015-01-01

    Small bodies record the chemical, physical, and dynamical processes that gave birth to and shaped the solar system. The great variety of small bodies reflects the diversity of both their genesis and their histories. The DARe mission conducts a critical test of how small body populations reflect a history of planetary migration and planetesimal scattering. This understanding is crucial for planning future NASA missions and placing current and past missions into context.

  12. 76 FR 19282 - Direct Investment Surveys: Alignment of Regulations With Current Practices

    Science.gov (United States)

    2011-04-07

    ... eliminated from the regulations are: a survey of foreign direct investment in the U.S. seafood industry (BE... Foreign Person BE-21, Survey of Foreign Direct Investment in U.S. Business Enterprises Engaged in the... established or acquired entity. The data had been used to measure the amount of new foreign direct......

  13. Precise Distances for Main-Belt Asteroids in Only Two Nights

    CERN Document Server

    Heinze, Aren N

    2015-01-01

    We present a method for calculating precise distances to asteroids using only two nights of data from a single location --- far too little for an orbit --- by exploiting the angular reflex motion of the asteroids due to Earth's axial rotation. We refer to this as the rotational reflex velocity method. While the concept is simple and well-known, it has not been previously exploited for surveys of main-belt asteroids. We offer a mathematical development, estimates of the errors of the approximation, and a demonstration using a sample of 197 asteroids observed for two nights with a small, 0.9-meter telescope. This demonstration used digital tracking to enhance detection sensitivity for faint asteroids, but our distance determination works with any detection method. Forty-eight asteroids in our sample had known orbits prior to our observations, and for these we demonstrate a mean fractional error of only 1.6% between the distances we calculate and those given in ephemerides from the Minor Planet Center. In contra...

  14. The Kilometer-Sized Main Belt Asteroid Population as Revealed by Spitzer

    CERN Document Server

    Ryan, Erin Lee; Shenoy, Sachindev S; Woodward, Charles E; Carey, Sean; Noriega-Crespo, Alberto; Kraemer, Kathleen E; Price, Stephan D

    2012-01-01

    Multi-epoch Spitzer Space Telescope 24 micron data is utilized from the MIPSGAL and Taurus Legacy surveys to detect asteroids based on their relative motion. These infrared detections are matched to known asteroids and rotationally averaged diameters and albedos are derived using the Near Earth Asteroid Model (NEATM) in conjunction with Monte Carlo simulations for 1835 asteroids ranging in size from 0.2 to 143.6 km. A small subsample of these objects was also detected by IRAS or MSX and the single wavelength albedo and diameter fits derived from this data are within 5% of the IRAS and/or MSX derived albedos and diameters demonstrating the robustness of our technique. The mean geometric albedo of the small main belt asteroids in this sample is p_V = 0.138 with a sample standard deviation of 0.105. The albedo distribution of this sample is far more diverse than the IRAS or MSX samples. The cumulative size-frequency distribution of asteroids in the main belt at small diameters is directly derived. Completeness l...

  15. State of the art of cattle dehorning in the EU Member States. A quantitative survey of the current practices

    NARCIS (Netherlands)

    Cozzi, G.; Gottardo, F.; Brscic, M.; Contiero, B.; Irrgang, N.; Knierim, U.; Pentelescu, O.; Windig, J.J.; Mirabito, L.; Kling Eveillard, F.; Dockes, A.C.; Veissier, I.; Velarde, A.; Fuentes, C.; Dalmau, A.; Winckler, C.

    2015-01-01

    A survey was carried out to describe the extent and current practice of cattle disbudding/dehorning in the EU Member States. Disbudding was defined as removal of horns in calves of up to 2 months of age, whereas dehorning was defined as removal of horns in older animals. Specific questionnaires were

  16. Bifidobacterium asteroides PRL2011 genome analysis reveals clues for colonization of the insect gut.

    Directory of Open Access Journals (Sweden)

    Francesca Bottacini

    Full Text Available Bifidobacteria are known as anaerobic/microaerophilic and fermentative microorganisms, which commonly inhabit the gastrointestinal tract of various animals and insects. Analysis of the 2,167,301 bp genome of Bifidobacterium asteroides PRL2011, a strain isolated from the hindgut of Apis mellifera var. ligustica, commonly known as the honey bee, revealed its predicted capability for respiratory metabolism. Conservation of the latter gene clusters in various B. asteroides strains enforces the notion that respiration is a common metabolic feature of this ancient bifidobacterial species, which has been lost in currently known mammal-derived Bifidobacterium species. In fact, phylogenomic based analyses suggested an ancient origin of B. asteroides and indicates it as an ancestor of the genus Bifidobacterium. Furthermore, the B. asteroides PRL2011 genome encodes various enzymes for coping with toxic products that arise as a result of oxygen-mediated respiration.

  17. Apollo asteroids (1566) Icarus and 2007 MK6: Icarus family members?

    CERN Document Server

    Ohtsuka, K; Ito, T; Kasuga, T; Watanabe, J; Kinoshita, D; Sekiguchi, T; Asher, D J; Nakano, S

    2007-01-01

    Although it is more complicated to search for near-Earth object (NEO) families than main belt asteroid (MBA) families, since differential orbital evolution within a NEO family can cause current orbital elements to drastically differ from each other, we have found that Apollo asteroids (1566) Icarus and the newly discovered 2007 MK6 are almost certainly related. Specifically, their orbital evolutions show a similar profile, time shifted by only ~1000 yr, based on our time-lag theory. The dynamical relationship between Icarus and 2007 MK6 along with a possible dust band, the Taurid-Perseid meteor swarm, implies the first detection of an asteroidal NEO family, namely the "Icarus asteroid family".

  18. Bifidobacterium asteroides PRL2011 genome analysis reveals clues for colonization of the insect gut.

    Science.gov (United States)

    Bottacini, Francesca; Milani, Christian; Turroni, Francesca; Sánchez, Borja; Foroni, Elena; Duranti, Sabrina; Serafini, Fausta; Viappiani, Alice; Strati, Francesco; Ferrarini, Alberto; Delledonne, Massimo; Henrissat, Bernard; Coutinho, Pedro; Fitzgerald, Gerald F; Margolles, Abelardo; van Sinderen, Douwe; Ventura, Marco

    2012-01-01

    Bifidobacteria are known as anaerobic/microaerophilic and fermentative microorganisms, which commonly inhabit the gastrointestinal tract of various animals and insects. Analysis of the 2,167,301 bp genome of Bifidobacterium asteroides PRL2011, a strain isolated from the hindgut of Apis mellifera var. ligustica, commonly known as the honey bee, revealed its predicted capability for respiratory metabolism. Conservation of the latter gene clusters in various B. asteroides strains enforces the notion that respiration is a common metabolic feature of this ancient bifidobacterial species, which has been lost in currently known mammal-derived Bifidobacterium species. In fact, phylogenomic based analyses suggested an ancient origin of B. asteroides and indicates it as an ancestor of the genus Bifidobacterium. Furthermore, the B. asteroides PRL2011 genome encodes various enzymes for coping with toxic products that arise as a result of oxygen-mediated respiration.

  19. Distribution of spin-axes longitudes and shape elongations of main-belt asteroids

    Science.gov (United States)

    Cibulková, H.; Ďurech, J.; Vokrouhlický, D.; Kaasalainen, M.; Oszkiewicz, D. A.

    2016-11-01

    Context. Large all-sky surveys provide us with a lot of photometric data that are sparse in time (typically a few measurements per night) and can be potentially used for the determination of shapes and rotational states of asteroids. The method generally used to derive these parameters is the light curve inversion. However, for most asteroids their sparse data are not accurate enough to derive a unique model and the light curve inversion method is thus not very efficient. Aims: To fully utilize photometry sparse in time, we developed a new simplified model and applied it on the data from the Lowell photometric database. Our aim was to derive spin axis orientations and shape elongations of asteroids and to find out if there are some differences in distributions of these parameters for selected subpopulations. Methods: We modeled asteroids as geometrically scattering triaxial ellipsoids. Observed values of mean brightness and the dispersion of brightness were compared with computed values obtained from the parameters of the model, i.e., the ecliptical longitude λ and latitude β of the pole and the ratios a/b, b/c of axes of the ellipsoid. These parameters were optimized to get the best agreement with the observation. Results: We found that the distribution of λ for main-belt asteroids is not uniform and is dependent on the inclination of the orbit. Surprisingly, the nonuniformity of λ distribution is larger for asteroids residing on low-inclination orbits. We also studied distributions of a/b for several groups of asteroids and found that small asteroids (D< 25 km) are on average more elongated than large ones.

  20. Ordinary Chondrite Spectral Signatures in the 243 Ida Asteroid System

    Science.gov (United States)

    Granahan, J. C.

    2012-12-01

    The NASA Galileo spacecraft observed asteroid 243 Ida and satellite Dactyl on August 28, 1993, with the Near Infrared Mapping Spectrometer (NIMS) at wavelengths ranging from 0.7 to 5.2 micrometers[Carlson et al., 1994]. Work is being conducted to produce radiance-calibrated spectral images of 243 Ida consisting of 17-channel, 299 meters per pixel files and a 102-channel, 3.2 kilometer per pixel NIMS observations of 243 Ida for the NASA Planetary Data System (PDS). These data are currently archived in PDS as uncalibrated data number counts. Radiometric calibrated 17-channel and 102-channel NIMS spectral data files of Dactyl and light curve 243 Ida observations are also being prepared. Analysis of this infrared asteroid data has confirmed that both 243 Ida and Dactyl are S-type asteroid objects and found that their olivine and pyroxene mineral abundances are consistent with that of ordinary chondrite meteorites. Tholen [1989] identified 243 Ida and Chapman et al. [1995] identified Dactyl as S-type asteroids on the basis of spectral data ranging from 0.4 to 1.0 micrometers. S-type are described [Tholen, 1989] as asteroids with a moderate albedos, a moderate to strong absorption feature shortward of 0.7 micrometers, and moderate to nonexistent absorption features longward of 0.7 micrometers. DeMeo et al. [2009] found 243 Ida to be a Sw asteroid based on Earth-based spectral observations 0.4 to 2.5 micrometers in range. Sw is a subclass of S-type asteroids that has a space weathering spectral component [DeMeo et al., 2009]. The NIMS data 243 Ida and Dactyl processed in this study exhibit signatures consistent with the Sw designation of DeMeo et al. [2009]. Measurements of olivine and pyroxene spectral bands were also conducted for the NIMS radiance data of 243 Ida and Dactyl. Band depth and band center measurements have been used to compare S-type asteroids with those of meteorites [Dunn et al., 2010; Gaffey et al., 1993]. The 243 Ida spectra were found to be consistent

  1. Eccentricity distribution in the main asteroid belt

    Science.gov (United States)

    Malhotra, Renu; Wang, Xianyu

    2017-03-01

    The observationally complete sample of the main belt asteroids now spans more than two orders of magnitude in size and numbers more than 64 000 (excluding collisional family members). We undertook an analysis of asteroids' eccentricities and their interpretation with simple physical models. We find that a century old conclusion that the asteroids' eccentricities follow a Rayleigh distribution holds for the osculating eccentricities of large asteroids, but the proper eccentricities deviate from a Rayleigh distribution; there is a deficit of eccentricities smaller than ∼0.1 and an excess of larger eccentricities. We further find that the proper eccentricities do not depend significantly on asteroid size but have strong dependence on heliocentric distance; the outer asteroid belt follows a Rayleigh distribution, but the inner belt is strikingly different. Eccentricities in the inner belt can be modelled as a vector sum of a primordial eccentricity vector of random orientation and magnitude drawn from a Rayleigh distribution of parameter ∼0.06, and an excitation of random phase and magnitude ∼0.13. These results imply that when a late dynamical excitation of the asteroids occurred, it was independent of asteroid size and was stronger in the inner belt than in the outer belt. We discuss implications for the primordial asteroid belt and suggest that the observationally complete sample size of main belt asteroids is large enough that more sophisticated model-fitting of the eccentricities is warranted and could serve to test alternative theoretical models of the dynamical excitation history of asteroids and its links to the migration history of the giant planets.

  2. On Possibility of Direct Asteroid Deflection by Electric Solar Wind Sail

    Science.gov (United States)

    Merikallio, Sini; Janhunen, Pekka

    2010-05-01

    The Electric Solar Wind Sail (E-sail) is a new propulsion method for interplanetary travel which was invented in 2006 and is currently under development. The E-sail uses charged tethers to extract momentum from the solar wind particles to obtain propulsive thrust. According to current estimates, the E-sail is 2-3 orders of magnitude better than traditional propulsion methods (chemical rockets and ion engines) in terms of produced lifetime-integrated impulse per propulsion system mass. Here we analyze the problem of using the E-sail for directly deflecting an Earth-threatening asteroid. The problem then culminates into how to attach the E-sail device to the asteroid. We assess a number of alternative attachment strategies and arrive at a recommendation of using the gravity tractor method because of its workability for a wide variety of asteroid types. We also consider possible techniques to scale up the E-sail force beyond the baseline one Newton level to deal with more imminent or larger asteroid or cometary threats. As a baseline case we consider a 3 million ton asteroid which can be deflected with a baseline 1 N E-sail in 5-10 years. Once developed, the E-sail would appear to provide a safe and reasonably low-cost way of deflecting dangerous asteroids and other heavenly bodies in cases where the collision threat becomes known several years in advance.

  3. KOALA: 3-D shape of asteroids from multi-data inversion

    Science.gov (United States)

    Carry, B.; Kaasalainen, M.; Merline, W. J.; Drummond, J. D.; Durech, J.; Berthier, J.; Conrad, A.

    2011-10-01

    We describe our on-going observing program to determine the physical properties of asteroids from groundbased facilities. We combine disk-resolved images from adaptive optics, optical lightcurves, and stellar occultations to put tighter constraints on the spin, 3-D shape, and size of asteroids. We will discuss the relevance of the determination of physical properties to help understand the asteroid population (e.g., density, composition, and non-gravitational forces). We will then briefly describe our multi-data inversion algorithm KOALA (Carry et al. 2010a, Kaasalainen 2011, see also Kaasalainen et al., same meeting), which allows the determination of certain physical properties of an asteroid from the combination of different techniques of observation. A comparison of results obtained with KOALA on asteroid (21) Lutetia, prior to the ESA Rosetta flyby, with the high spatial resolution images returned from that flyby, will then be presented, showing the high accuracy of KOALA inversion. Finally, we will describe our current development of the algorithm, and focus on examples of other asteroids currently being studied with KOALA.

  4. A national survey of how acupuncture is currently used in midwifery care at Swedish maternity units

    OpenAIRE

    Martensson, Lena; Kvist, LInda; Hermansson, Evelyn

    2011-01-01

    Objective: it is not known how acupuncture is used in midwifery care in Sweden and what kind of requirements health-care providers have for midwives and acupuncture training programmes. The aims of this study were to survey indications for the use of acupuncture in midwifery care in Sweden, and to examine the criteria and requirements used for purchase of acupuncture education programmes. Design: a postal survey using a structured questionnaire. Setting: 45 maternity units in Sweden. Particip...

  5. Domestic Violence Perpetrator Programs in Europe, Part I : A survey of Current Practice

    OpenAIRE

    Hamilton, Leah; Koehler, Johann A.; Lösel, Friedrich A.

    2014-01-01

    Most research on domestic violence perpetrator programs has been carried out in North America. It does not yet provide a clear picture on what works with these offenders and cannot be generalized to other cultural and legal systems. Therefore, in Part I of this article, we present the results of a survey of 54 programs that were in place in 19 European countries that addressed the programs’ practice and effects. The survey captured data about program design, delivery, administration, infrastr...

  6. Neuroimaging training among neuropsychologists: A survey of the state of current training and recommendations for trainees

    OpenAIRE

    2013-01-01

    Neuroimaging has gained widespread use in neuropsychological research and practice. However, there are neither established guidelines on how neuropsychologists might become competent researchers or consumers of neuroimaging data, nor any published studies describing the state of neuroimaging training among neuropsychologists. We report the results of two online surveys, one of 13 expert neuropsychologist-neuroimagers, whose responses informed the formulation of a second, larger survey to neur...

  7. GRASPING THE NATURE OF POTENTIALLY HAZARDOUS ASTEROIDS

    Energy Technology Data Exchange (ETDEWEB)

    Perna, D.; Barucci, M. A.; Fornasier, S.; Deshapriya, J. D. P. [LESIA—Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon (France); Dotto, E.; Ieva, S.; Epifani, E. Mazzotta [INAF—Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monte Porzio Catone (Roma) (Italy); Bernardi, F. [SpaceDyS, via Mario Giuntini 63, I-56023 Cascina (Pisa) (Italy); Luise, F. De [INAF—Osservatorio Astronomico di Teramo, via Mentore Maggini snd, I-64100 Teramo (Italy); Perozzi, E. [Deimos Space, Strada Buchesti 75-77, Bucharest (Romania); Rossi, A. [IFAC—CNR, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Firenze) (Italy); Micheli, M., E-mail: davide.perna@obspm.fr [ESA—NEOCC, ESRIN, via Galileo Galilei 64, I-00044 Frascati (Rome) (Italy)

    2016-01-15

    Through their delivery of water and organics, near-Earth objects (NEOs) played an important role in the emergence of life on our planet.  However, they also pose a hazard to the Earth, as asteroid impacts could significantly affect our civilization. Potentially hazardous asteroids (PHAs) are those that, in principle, could possibly impact the Earth within the next century, producing major damage. About 1600 PHAs are currently known, from an estimated population of 4700 ± 1450. However, a comprehensive characterization of the PHA physical properties is still missing. Here we present spectroscopic observations of 14 PHAs, which we have used to derive their taxonomy, meteorite analogs, and mineralogy. Combining our results with the literature, we investigated how PHAs are distributed as a function of their dynamical and physical properties. In general, the “carbonaceous” PHAs seem to be particularly threatening, because of their high porosity (limiting the effectiveness of the main deflection techniques that could be used in space) and low inclination and minimum orbit intersection distance (MOID) with the Earth (favoring more frequent close approaches). V-type PHAs also present low MOID values, which can produce frequent close approaches (as confirmed by the recent discovery of a limited space weathering on their surfaces). We also identified those specific objects that deserve particular attention because of their extreme rotational properties, internal strength, or possible cometary nature. For PHAs and NEOs in general, we identified a possible anti-correlation between the elongation and the rotational period, in the range of P{sub rot} ≈ 5–80 hr. This would be compatible with the behavior of gravity-dominated aggregates in rotational equilibrium. For periods ≳80–90 hr, such a trend stops, possibly under the influence of the YORP effect and collisions. However, the statistics is very low, and further observational and theoretical work is required

  8. The Steward Observatory asteroid relational database

    Science.gov (United States)

    Sykes, Mark V.; Alvarezdelcastillo, Elizabeth M.

    1992-01-01

    The Steward Observatory Asteroid Relational Database (SOARD) was created as a flexible tool for undertaking studies of asteroid populations and sub-populations, to probe the biases intrinsic to asteroid databases, to ascertain the completeness of data pertaining to specific problems, to aid in the development of observational programs, and to develop pedagogical materials. To date SOARD has compiled an extensive list of data available on asteroids and made it accessible through a single menu-driven database program. Users may obtain tailored lists of asteroid properties for any subset of asteroids or output files which are suitable for plotting spectral data on individual asteroids. A browse capability allows the user to explore the contents of any data file. SOARD offers, also, an asteroid bibliography containing about 13,000 references. The program has online help as well as user and programmer documentation manuals. SOARD continues to provide data to fulfill requests by members of the astronomical community and will continue to grow as data is added to the database and new features are added to the program.

  9. [Asteroid hyalopathy (benson's disease): about a case].

    Science.gov (United States)

    Bienvenu, Yogolelo Asani; Angel, Musau Nkola; Leon, Kabamba Ngombe; Socrate, Kapalu Mwangala; Bruno, Iye Ombamba Kayimba; Gaby, Chenge Borasisi

    2017-01-01

    We here report a case of a 58 year-old diabetic male patient with asteroid hyalopathy, an affection rarely described in the literature. This study can help focus the attention of scientists on the pathologies of the vitreous disorders in diabetic patients as well as on other systemic diseases asteroid hyalopathy may be associated with.

  10. Periodic Motion near the Surface of Asteroids

    CERN Document Server

    Jiang, Yu; Li, Hengnian

    2015-01-01

    We are interested in the periodic motion and bifurcations near the surface of an asteroid. The gravity field of an irregular asteroid and the equation of motion of a particle near the surface of an asteroid are studied. The periodic motions around the major body of triple asteroid 216 Kleopatra and the OSIRIS REx mission target asteroid 101955 Bennu are discussed. We find that motion near the surface of an irregular asteroid is quite different from the motion near the surface of a homoplastically spheroidal celestial body. The periodic motions around the asteroid 101955 Bennu and 216 Kleopatra indicate that the geometrical shapes of the orbits are probably very sophisticated. There exist both stable periodic motions and unstable periodic motions near the surface of the same irregular asteroid. This periodic motion which is unstable can be resonant or non resonant. The period doubling bifurcation and pseudo period doubling bifurcation of periodic orbits coexist in the same gravity field of the primary of the t...

  11. New insights into main belt asteroid collisional lifetimes

    Science.gov (United States)

    Henych, Tomas; Holsapple, Keith

    2016-10-01

    We are developing a new Monte Carlo code to study the collisional and spin evolution of main belt asteroids. A byproduct is information on asteroid lifetimes. We find new interpretations and values of those lifetimes.In the conventional approach, the "collisional lifetime" is measured by the time when an asteroid is struck by an impactor large enough to remove one-half of the target's mass. That event is called a catastrophic disruption (CD). From an assumed population of impactors and Poisson statistics, one can estimate the largest expected impactor to impact in a given time interval to get its expected collisional lifetime. However, our Monte Carlo simulations give lifetimes that are distinctly shorter. That raises questions about the basic definition of catastrophic disruption.During its presence in the main belt, many other asteroids of all sizes continually strike a target asteroid. Before the CD one happens, there are many small impacts, and a few less than but not equal to the CD one. Each impact erodes the target asteroid. Very commonly, it is eroded to a much smaller mass before some CD event. We will present examples.So what shall we define as its collisional lifetime? Should it be the time for which its mass is reduced to one-half of its original mass, irrespective of how that happened, perhaps from many impacts? Or when any single impact reduces its mass to one-half of its original mass? Or when a single impact reduces it to one-half of its current mass?We propose that collisional lifetime is defined as the time at which it reaches 50% of its original mass, from any combination of small and/or large events. We use cratering and ejecta scaling formulas (e.g. Holsapple, 1993, Housen and Holsapple, 2011) to calculate the eroded mass history of the target for a history of impactors and calculate the outcome of any impact using the current size. In the gravity regime, the eroded body is easier to disrupt. We will present our lifetime estimates and those of

  12. Quantifying the lack of differentiated material amongst asteroid families

    Science.gov (United States)

    Jacobson, Seth A.; Morbidelli, Alessandro

    2016-10-01

    Asteroid families are created during catastrophic and cratering events on parent bodies. Family identification and parent body reconstruction has been a focus of a number of prior works (e.g. Tanga et al. 1999, Durda et al. 2007, Broz et al. 2003). These works used identified family members from dynamical hierarchical clustering methods to estimate family size distributions. From these size distributions parent body masses can be estimated. The asteroid family parent body mass is a lower limit on the accreted planetesimal mass, since it could have been a fragment of some larger body. Different models of planetesimal accretion make different predictions for the size at which significant melting and differentiation should occur. Here, we test these models by comparing the lower limit on the accreted planetesimal mass to the amount of expected exposed crust, mantle and core material. The fraction of mass in the largest remnant compared to the parent body mass can differentiate between catastrophic and cratering events as well as provide an assessment for the minimum exposed depth of the parent body. We make upper limit estimates on the amount of differentiated mass contained in each family using spectroscopic and color surveys have become complete for V-type and A-type asteroids at relevant sizes. We compare these masses with those expected from totally and partially differentiated bodies.

  13. Size Distribution of Main-Belt Asteroids with High Inclination

    CERN Document Server

    Terai, Tsuyoshi

    2010-01-01

    We investigated the size distribution of high-inclination main-belt asteroids (MBAs) to explore asteroid collisional evolution under hypervelocity collisions of around 10 km/s. We performed a wide-field survey for high-inclination sub-km MBAs using the 8.2-m Subaru Telescope with the Subaru Prime Focus Camera (Suprime-Cam). Suprime-Cam archival data were also used. A total of 616 MBA candidates were detected in an area of 9.0 deg^2 with a limiting magnitude of 24.0 mag in the SDSS r filter. Most of candidate diameters were estimated to be smaller than 1 km. We found a scarcity of sub-km MBAs with high inclination. Cumulative size distributions (CSDs) were constructed using Subaru data and published asteroid catalogs. The power-law indexes of the CSDs were 2.17 +/- 0.02 for low-inclination ( 15 deg) MBAs in the 0.7-50 km diameter range. The high-inclination MBAs had a shallower CSD. We also found that the CSD of S-like MBAs had a small slope with high inclination, whereas the slope did not vary with inclinatio...

  14. The relationship between repeated unintended pregnancies and current contraceptive use: National Survey of Family Growth (NSFG) 2006-2008 data.

    Science.gov (United States)

    Matsuda, Yui; Masho, Saba; McGrath, Jacqueline M

    2012-01-01

    The purpose of this study is to examine the relationship between the number of unintended pregnancies and current contraceptive use. This is a secondary analysis of a cross-sectional survey, the 2006-2008 National Survey of Family Growth, which included 4,052 women between the ages of 15 and 44 years. A statistically significant association was found between the nonuse of contraceptives and repeated unintended pregnancies, as well as among those who used an effective contraceptive method and repeated unintended pregnancies. Nurses are encouraged to ask questions about intendedness of pregnancies during women's visits and help women choose appropriate contraceptive methods.

  15. The Hoffmeister asteroid family

    Science.gov (United States)

    Carruba, V.; Novaković, B.; Aljbaae, S.

    2017-03-01

    The Hoffmeister family is a C-type group located in the central main belt. Dynamically, it is important because of its interaction with the ν1C nodal secular resonance with Ceres, which significantly increases the dispersion in inclination of family members at a lower semimajor axis. As an effect, the distribution of inclination values of the Hoffmeister family at a semimajor axis lower than its centre is significantly leptokurtic, and this can be used to set constraints on the terminal ejection velocity field of the family at the time it was produced. By performing an analysis of the time behaviour of the kurtosis of the vW component of the ejection velocity field [γ2(vW)], as obtained from Gauss' equations, for different fictitious Hoffmeister families with different values of the ejection velocity field, we were able to exclude that the Hoffmeister family should be older than 335 Myr. Constraints from the currently observed inclination distribution of the Hoffmeister family suggest that its terminal ejection velocity parameter VEJ should be lower than 25 m s-1. Results of a Yarko-YORP Monte Carlo method to family dating, combined with other constraints from inclinations and γ2(vW), indicate that the Hoffmeister family should be 220^{+60}_{-40} Myr old, with an ejection parameter VEJ = 20 ± 5 m s-1.

  16. Origin of igneous meteorites and differentiated asteroids

    Science.gov (United States)

    Scott, E.; Goldstein, J.; Asphaug, E.; Bottke, W.; Moskovitz, N.; Keil, K.

    2014-07-01

    Introduction: Igneously formed meteorites and asteroids provide major challenges to our understanding of the formation and evolution of the asteroid belt. The numbers and types of differentiated meteorites and non-chondritic asteroids appear to be incompatible with an origin by fragmentation of numerous Vesta-like bodies by hypervelocity impacts in the asteroid belt over 4 Gyr. We lack asteroids and achondrites from the olivine-rich mantles of the parent bodies of the 12 groups of iron meteorites and the ˜70 ungrouped irons, the 2 groups of pallasites and the 4--6 ungrouped pallasites. We lack mantle and core samples from the parent asteroids of the basaltic achondrites that do not come from Vesta, viz., angrites and the ungrouped eucrites like NWA 011 and Ibitira. How could core samples have been extracted from numerous differentiated bodies when Vesta's basaltic crust was preserved? Where is the missing Psyche family of differentiated asteroids including the complementary mantle and crustal asteroids [1]? Why are meteorites derived from far more differentiated parent bodies than chondritic parent bodies even though C and S class chondritic asteroids dominate the asteroid belt? New paradigm. Our studies of meteorites, impact modeling, and dynamical studies suggest a new paradigm in which differentiated asteroids accreted at 1--2 au less than 2 Myr after CAI formation [2]. They were rapidly melted by 26Al and disrupted by hit-and-run impacts [3] while still molten or semi-molten when planetary embryos were accreting. Metallic Fe-Ni bodies derived from core material cooled rapidly with little or no silicate insulation less than 4 Myr after CAI formation [4]. Fragments of differentiated planetesimals were subsequently tossed into the asteroid belt. Meteorite evidence for early disruption of differentiated asteroids. If iron meteorites were samples of Fe-Ni cores of bodies that cooled slowly inside silicate mantles over ˜50--100 Myr, irons from each core would have

  17. The Compositional Structure of the Asteroid Belt

    CERN Document Server

    DeMeo, Francesca E; Walsh, Kevin J; Chapman, Clark R; Binzel, Richard P

    2015-01-01

    The past decade has brought major improvements in large-scale asteroid discovery and characterization with over half a million known asteroids and over 100,000 with some measurement of physical characterization. This explosion of data has allowed us to create a new global picture of the Main Asteroid Belt. Put in context with meteorite measurements and dynamical models, a new and more complete picture of Solar System evolution has emerged. The question has changed from "What was the original compositional gradient of the Asteroid Belt?" to "What was the original compositional gradient of small bodies across the entire Solar System?" No longer is the leading theory that two belts of planetesimals are primordial, but instead those belts were formed and sculpted through evolutionary processes after Solar System formation. This article reviews the advancements on the fronts of asteroid compositional characterization, meteorite measurements, and dynamical theories in the context of the heliocentric distribution of...

  18. Measurement of Cohesion in Asteroid Regolith Materials

    Science.gov (United States)

    Kleinhenz, Julie; Gaier, James; Waters, Deborah; Harvey, Ralph; Zeszut, Zoe; Carreno, Brandon; Shober, Patrick

    2017-01-01

    There is increasing evidence that a large fraction of asteroids, and even Phobos, have such low densities (asteroids are thought to be made up of unconsolidated smaller particles of varying size referred to as rubble piles. Images of the asteroid Itokawa reinforce this hypothesis. What holds the rubble piles together? Gravitational forces alone are not strong enough to hold together rubble pile asteroids, at least not those that are rapidly spinning Van der Waals forces and or Electrostatic forces must therefore be responsible for holding them together. Previous work suggests that electrostatic forces, which are orders of magnitude stronger are far more likely. Charge build-up is a likely consequence of the interaction of airless bodies with the solar wind plasma, analogous to what has been proposed to occur on the moon. Objective: Experimentally measure cohesive forces relevant to those holding rubble pile asteroids together

  19. The Hawaii Trails Project: Comet-Hunting in the Main Asteroid Belt

    CERN Document Server

    Hsieh, Henry H

    2009-01-01

    The mysterious solar system object 133P/(7968) Elst-Pizarro is dynamically asteroidal, yet displays recurrent comet-like dust emission. Two scenarios were hypothesized to explain this unusual behavior: (1) 133P is a classical comet from the outer solar system that has evolved onto a main-belt orbit, or (2) 133P is a dynamically ordinary main-belt asteroid on which subsurface ice has recently been exposed. If (1) is correct, the expected rarity of a dynamical transition onto an asteroidal orbit implies that 133P could be alone in the main belt. In contrast, if (2) is correct, other icy main-belt objects should exist and could also exhibit cometary activity. Believing 133P to be a dynamically ordinary, yet icy main-belt asteroid, I set out to test the primary prediction of the hypothesis: that 133P-like objects should be common and could be found by an appropriately designed observational survey. I conducted just such a survey -- the Hawaii Trails Project -- of selected main-belt asteroids in a search for objec...

  20. OSIRIS-REx: Sample Return from Asteroid (101955) Bennu

    Science.gov (United States)

    Lauretta, D. S.; Balram-Knutson, S. S.; Beshore, E.; Boynton, W. V.; Drouet d'Aubigny, C.; DellaGiustina, D. N.; Enos, H. L.; Golish, D. R.; Hergenrother, C. W.; Howell, E. S.; Bennett, C. A.; Morton, E. T.; Nolan, M. C.; Rizk, B.; Roper, H. L.; Bartels, A. E.; Bos, B. J.; Dworkin, J. P.; Highsmith, D. E.; Lorenz, D. A.; Lim, L. F.; Mink, R.; Moreau, M. C.; Nuth, J. A.; Reuter, D. C.; Simon, A. A.; Bierhaus, E. B.; Bryan, B. H.; Ballouz, R.; Barnouin, O. S.; Binzel, R. P.; Bottke, W. F.; Hamilton, V. E.; Walsh, K. J.; Chesley, S. R.; Christensen, P. R.; Clark, B. E.; Connolly, H. C.; Crombie, M. K.; Daly, M. G.; Emery, J. P.; McCoy, T. J.; McMahon, J. W.; Scheeres, D. J.; Messenger, S.; Nakamura-Messenger, K.; Righter, K.; Sandford, S. A.

    2017-08-01

    In May of 2011, NASA selected the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission as the third mission in the New Frontiers program. The other two New Frontiers missions are New Horizons, which explored Pluto during a flyby in July 2015 and is on its way for a flyby of Kuiper Belt object 2014 MU69 on January 1, 2019, and Juno, an orbiting mission that is studying the origin, evolution, and internal structure of Jupiter. The spacecraft departed for near-Earth asteroid (101955) Bennu aboard an United Launch Alliance Atlas V 411 evolved expendable launch vehicle at 7:05 p.m. EDT on September 8, 2016, on a seven-year journey to return samples from Bennu. The spacecraft is on an outbound-cruise trajectory that will result in a rendezvous with Bennu in November 2018. The science instruments on the spacecraft will survey Bennu to measure its physical, geological, and chemical properties, and the team will use these data to select a site on the surface to collect at least 60 g of asteroid regolith. The team will also analyze the remote-sensing data to perform a detailed study of the sample site for context, assess Bennu's resource potential, refine estimates of its impact probability with Earth, and provide ground-truth data for the extensive astronomical data set collected on this asteroid. The spacecraft will leave Bennu in 2021 and return the sample to the Utah Test and Training Range (UTTR) on September 24, 2023.

  1. Current trends in robot assisted surgery: a survey of gynecologic oncologists.

    Science.gov (United States)

    duPont, Nefertiti C; Chandrasekhar, Rameela; Wilding, Gregory; Guru, Khurshid A

    2010-12-01

    To evaluate the perceptions of the importance and utility of robot assisted surgery in gynecologic oncology. A 39 question web-based survey was sent to members of the Society of Gynecologic Oncologists. The survey response rate was 28%, with 277 surveys completed. Nearly 40% of respondents felt robotic surgical training was required as a part of their career goals, and 73% of respondents have performed a robotic hysterectomy. Among respondents, 39% felt that robotic surgery was as good as laparoscopic surgery but 23% thought robot assisted surgery should be the gold standard for the treatment of endometrial cancer. Robot assisted surgery is gaining widespread acceptance and is perceived to be as good as laparoscopic surgery for the treatment of early stage endometrial and cervical cancers. Among respondents the greatest benefit of robot assisted surgery was its ease of use and perceived improvement in a patient's quality of life. Copyright © 2010 John Wiley & Sons, Ltd.

  2. Logistics Needs for Potential Deep Space Mission Scenarios Post Asteroid Crewed Mission

    Science.gov (United States)

    Lopez, Pedro, Jr.

    2015-01-01

    A deep-space mission has been proposed to identify and redirect an asteroid to a distant retrograde orbit around the moon, and explore it by sending a crew using the Space Launch System and the Orion spacecraft. The Asteroid Redirect Crewed Mission (ARCM), which represents the third segment of the Asteroid Redirect Mission (ARM), could be performed on EM-3 or EM-4 depending on asteroid return date. Recent NASA studies have raised questions on how we could progress from current Human Space Flight (HSF) efforts to longer term human exploration of Mars. This paper will describe the benefits of execution of the ARM as the initial stepping stone towards Mars exploration, and how the capabilities required to send humans to Mars could be built upon those developed for the asteroid mission. A series of potential interim missions aimed at developing such capabilities will be described, and the feasibility of such mission manifest will be discussed. Options for the asteroid crewed mission will also be addressed, including crew size and mission duration.

  3. Looking into the evolution of granular asteroids in the Solar System

    Directory of Open Access Journals (Sweden)

    Sánchez Paul

    2017-01-01

    Full Text Available By now it has been accepted that most of the small asteroids in the Solar System are granular aggregates kept together by gravitational and possibly, cohesive forces. These aggregates can form, deform and disrupt over millennia subjected to different internal and external factors that would ultimately determine how they evolve over time. Parameters such as porosity, cohesive and tensile strength, angles of friction, particle size distributions, stress states, heterogeneity and yield criteria among others, determine how these granular systems will react when subjected to different, changing, external factors. These external factors include solar photon momentum, gravitational tides, micro- and macro-impacts and are believed to have produced and shaped the current asteroid population. In our research we use a combination of Soil Mechanics theory, Soft-Sphere Discrete Element Method (SSDEM Simulations and Orbital Mechanics in order to understand how simulated, homogeneous and heterogeneous, ellipsoidal and spherical gravitational aggregates, a crude but useful representation of an asteroid, evolve when rotated to the point of disruption. Then, we compare our results to the shapes of observed asteroids as well as to the disruption patterns of a few active asteroids. Our results lead us to believe that the different shapes of observed asteroids as well as their unique disruption patterns could give us clues about their internal structure, strength and geophysical properties in general.

  4. Evaluating Different Scenarios for the Formation and Early Evolution of the Asteroid Belt

    Science.gov (United States)

    O'Brien, David P.; Walsh, Kevin J.

    2014-11-01

    The asteroid belt is dynamically excited, depleted in mass relative to the surface mass density of the rest of the Solar System, and contains numerous diverse taxonomic classes of asteroids that are partly, but not completely, radially mixed. In the 'classical' scenario of Solar System formation, the excitation, depletion and radial mixing of the asteroid belt is best explained by the effect of planetary embryos that are initially present in the primordial asteroid belt region [1-3]. In the more recent 'Grand Tack' scenario proposed by Walsh et al. [4], the early inward-then-outward migration of Jupiter in the gas disk initially depletes, then repopulates the asteroid belt with material scattered from both interior and exterior to Jupiter. Here we will examine in detail the model asteroid distributions resulting from these two scenarios for a range of parameters, and compare them to observational constraints on the current distribution of asteroids in the Solar System. We will also address the possible effects that late-stage planetesimal-driven migration and resonance-crossing of Jupiter and Saturn in the Nice Model [eg. 5,6] may have on the final asteroid distribution.[1] G.W. Wetherill, Icarus 100, 307-325 (1992)[2] J.-M. Petit et al., Icarus 153, 338-347 (2001)[3] D.P. O'Brien t al., Icarus 191, 434-452 (2007)[4] K.J. Walsh et al., Nature 475, 206-209 (2011)[5] K. Tsiganis et al., Nature 435, 459-461 (2005)[6] A. Morbidelli et al., AJ 140, 1391-1401 (2010)

  5. MASCOT—The Mobile Asteroid Surface Scout Onboard the Hayabusa2 Mission

    Science.gov (United States)

    Ho, Tra-Mi; Baturkin, Volodymyr; Grimm, Christian; Grundmann, Jan Thimo; Hobbie, Catherin; Ksenik, Eugen; Lange, Caroline; Sasaki, Kaname; Schlotterer, Markus; Talapina, Maria; Termtanasombat, Nawarat; Wejmo, Elisabet; Witte, Lars; Wrasmann, Michael; Wübbels, Guido; Rößler, Johannes; Ziach, Christian; Findlay, Ross; Biele, Jens; Krause, Christian; Ulamec, Stephan; Lange, Michael; Mierheim, Olaf; Lichtenheldt, Roy; Maier, Maximilian; Reill, Josef; Sedlmayr, Hans-Jürgen; Bousquet, Pierre; Bellion, Anthony; Bompis, Olivier; Cenac-Morthe, Celine; Deleuze, Muriel; Fredon, Stephane; Jurado, Eric; Canalias, Elisabet; Jaumann, Ralf; Bibring, Jean-Pierre; Glassmeier, Karl Heinz; Hercik, David; Grott, Matthias; Celotti, Luca; Cordero, Federico; Hendrikse, Jeffrey; Okada, Tatsuaki

    2016-04-01

    On December 3rd, 2014, the Japanese Space Agency (JAXA) launched successfully the Hayabusa2 (HY2) spacecraft to its journey to Near Earth asteroid (162173) Ryugu. Aboard this spacecraft is a compact landing package, MASCOT (Mobile Asteroid surface SCOuT), which was developed by the German Aerospace Centre (DLR) in collaboration with the Centre National d'Etudes Spatiales (CNES). Similar to the famous predecessor mission Hayabusa, Hayabusa2, will also study an asteroid and return samples to Earth. This time, however, the target is a C-type asteroid which is considered to be more primitive than (25143) Itokawa and provide insight into an even earlier stage of our Solar System. Upon arrival at asteroid Ryugu in 2018, MASCOT will be released from the HY2 spacecraft and gently descend by free fall from an altitude of about 100 m to the surface of the asteroid. After a few bounces, the lander will come to rest at the surface and perform its scientific investigations of the surface structure and mineralogical composition, the thermal behaviour and the magnetic properties by operating its four scientific instruments. Those include an IR imaging spectrometer (MicrOmega, IAS Paris), a camera (MASCAM, DLR Berlin), a radiometer (MARA, DLR Berlin) and a magnetometer (MASMAG, TU Braunschweig). In order to allow optimized payload operations the thermal design of MASCOT is required to cope with the contrasting requirements of the 4-year cruise in cold environment versus the hot conditions on the surface of the asteroid. Operations up to 2 asteroid days (˜16 hours) based on a primary battery are currently envisaged. A mobility mechanism allows locomotion on the surface. The mechanism is supported by an attitude and motion sensing system and an intelligent autonomy manager, which is implemented in the onboard software that enables MASCOT to operate fully independently when ground intervention is not available.

  6. Asteroid 2014 YX_49: a large transient Trojan of Uranus

    Science.gov (United States)

    de la Fuente Marcos, C.; de la Fuente Marcos, R.

    2017-01-01

    In the outer Solar system, primordial Trojan asteroids may have remained dynamically stable for billions of years. Several thousands of them accompany Jupiter in its journey around the Sun and a similarly large population may be hosted by Neptune. In addition, recently captured or transient Jovian and Neptunian Trojans are not uncommon. In contrast, no Trojans of Saturn have been found yet and just one Uranian Trojan is known, 2011 QF99. Here, we discuss the identification of a second Trojan of Uranus: 2014 YX49. Like 2011 QF99, 2014 YX49 is a transient L4 Trojan although it orbits at higher inclination (25.55 vs. 10.83), is larger (absolute magnitude of 8.5 vs. 9.7) and its libration period is slightly shorter (5.1 vs. 5.9 kyr); contrary to 2011 QF99, its discovery was not the result of a targeted survey. It is less stable than 2011 QF99; our extensive N-body simulations show that 2014 YX49 may have been following a tadpole trajectory ahead of Uranus for about 60 kyr and it can continue doing so for another 80 kyr. Our analysis suggests that it may remain as co-orbital for nearly 1 Myr. As in the case of 2011 QF99, the long-term stability of 2014 YX49 is controlled by Jupiter and Neptune, but it is currently trapped in the 7:20 mean motion resonance with Saturn. Consistently, the dynamical mechanism leading to the capture into and the ejection from the Trojan state involves ephemeral multibody mean motion resonances.

  7. Asteroids Outreach Toolkit Development: Using Iterative Feedback In Informal Education

    Science.gov (United States)

    White, Vivian; Berendsen, M.; Gurton, S.; Dusenbery, P. B.

    2011-01-01

    The Night Sky Network is a collaboration of close to 350 astronomy clubs across the US that actively engage in public outreach within their communities. Since 2004, the Astronomical Society of the Pacific has been creating outreach ToolKits filled with carefully crafted sets of physical materials designed to help these volunteer clubs explain the wonders of the night sky to the public. The effectiveness of the ToolKit activities and demonstrations is the direct result of a thorough testing and vetting process. Find out how this iterative assessment process can help other programs create useful tools for both formal and informal educators. The current Space Rocks Outreach ToolKit focuses on explaining asteroids, comets, and meteorites to the general public using quick, big-picture activities that get audiences involved. Eight previous ToolKits cover a wide range of topics from the Moon to black holes. In each case, amateur astronomers and the public helped direct the development the activities along the way through surveys, focus groups, and active field-testing. The resulting activities have been embraced by the larger informal learning community and are enthusiastically being delivered to millions of people across the US and around the world. Each ToolKit is delivered free of charge to active Night Sky Network astronomy clubs. All activity write-ups are available free to download at the website listed here. Amateur astronomers receive frequent questions from the public about Earth impacts, meteors, and comets so this set of activities will help them explain the dynamics of these phenomena to the public. The Space Rocks ToolKit resources complement the Great Balls of Fire museum exhibit produced by Space Science Institute's National Center for Interactive Learning and scheduled for release in 2011. NSF has funded this national traveling exhibition and outreach ToolKit under Grant DRL-0813528.

  8. Asteroid 2014 YX49: a large transient Trojan of Uranus

    Science.gov (United States)

    de la Fuente Marcos, C.; de la Fuente Marcos, R.

    2017-05-01

    In the outer Solar system, primordial Trojan asteroids may have remained dynamically stable for billions of years. Several thousands of them accompany Jupiter in its journey around the Sun and a similarly large population may be hosted by Neptune. In addition, recently captured or transient Jovian and Neptunian Trojans are not uncommon. In contrast, no Trojans of Saturn have been found yet and just one Uranian Trojan is known, 2011 QF99. Here, we discuss the identification of a second Trojan of Uranus: 2014 YX49. Like 2011 QF99, 2014 YX49 is a transient L4 Trojan although it orbits at higher inclination (25.55° versus 10.83°), is larger (absolute magnitude of 8.5 versus 9.7) and its libration period is slightly shorter (5.1 versus 5.9 kyr); contrary to 2011 QF99, its discovery was not the result of a targeted survey. It is less stable than 2011 QF99; our extensive N-body simulations show that 2014 YX49 may have been following a tadpole trajectory ahead of Uranus for about 60 kyr and it can continue doing so for another 80 kyr. Our analysis suggests that it may remain as co-orbital for nearly 1 Myr. As in the case of 2011 QF99, the long-term stability of 2014 YX49 is controlled by Jupiter and Neptune, but it is currently trapped in the 7:20 mean motion resonance with Saturn. Consistently, the dynamical mechanism leading to the capture into and the ejection from the Trojan state involves ephemeral multibody mean motion resonances.

  9. Reconstructing HST Images of Asteroids

    Science.gov (United States)

    Storrs, A. D.; Bank, S.; Gerhardt, H.; Makhoul, K.

    2003-12-01

    We present reconstructions of images of 22 large main belt asteroids that were observed by Hubble Space Telescope with the Wide-Field/Planetary cameras. All images were restored with the MISTRAL program (Mugnier, Fusco, and Conan 2003) at enhanced spatial resolution. This is possible thanks to the well-studied and stable point spread function (PSF) on HST. We present some modeling of this process and determine that the Strehl ratio for WF/PC (aberrated) images can be improved to 130 ratio of 80 We will report sizes, shapes, and albedos for these objects, as well as any surface features. Images taken with the WFPC-2 instrument were made in a variety of filters so that it should be possible to investigate changes in mineralogy across the surface of the larger asteroids in a manner similar to that done on 4 Vesta by Binzel et al. (1997). Of particular interest are a possible water of hydration feature on 1 Ceres, and the non-observation of a constriction or gap between the components of 216 Kleopatra. Reduction of this data was aided by grant HST-GO-08583.08A from the Space Telescope Science Institute. References: Mugnier, L.M., T. Fusco, and J.-M. Conan, 2003. JOSA A (submitted) Binzel, R.P., Gaffey, M.J., Thomas, P.C., Zellner, B.H., Storrs, A.D., and Wells, E.N. 1997. Icarus 128 pp. 95-103

  10. Current Practice vs. Guideline Based Imaging in Abdominal Radiology in the German Speaking Area: Results of an Online Survey.

    Science.gov (United States)

    Schreyer, A G; Wessling, J; Grenacher, L

    2016-03-01

    The working group for abdominal imaging within the German Roentgen Society (DRG) performed an online survey amongst radiologist concerning the current status of techniques for abdominal imaging. The results of this survey were compared with the most recent guidelines. We performed an online survey open for all members of the DRG during a 76-day period with 65 questions and an overall estimated time for finishing the questionnaire of 15 minutes concerning technical specifications for abdominal radiological imaging. The results were evaluated using descriptive statistics. 90 of all participants, who filled out the survey covering more than 80% of the questions, were included in the statistical evaluation. 27% of all participants were registered radiologists while 73% represented radiologists working in a hospital. Most participants worked in a managerial position. The participants gave detailed information regarding the radiological techniques used in dedicated organ systems (esophagus, stomach, pancreas, liver, small intestines, colon) regarding acquired contrast phases and oral and intravenous administration of contrast medium. The results confirm that most radiologists participating in this survey perform their examinations and choose their modalities in conformity with the current existing clinical guidelines. Because most clinical guidelines do not specify radiological examinations in detail, there is a noteworthy heterogeneity of the acquired contrast phases and major divergence in terms of technical parameters. Therefore a joint radiological effort should be initiated for developing and publishing updated radiological parameters for abdominal imaging. • In German speaking countries indications for abdominal radiological examinations are performed with a high compliance to published guidelines. • There is a significant heterogeneity regarding the acquisition of different contrast phases for parenchymal abdominal organs. • There is an urgent need to

  11. Prevalence and correlates of current daily use of electronic cigarettes in the European Union: analysis of the 2014 Eurobarometer survey.

    Science.gov (United States)

    Farsalinos, Konstantinos E; Poulas, Konstantinos; Voudris, Vassilis; Le Houezec, Jacques

    2017-03-04

    The study purpose was to analyze current daily and current daily nicotine-containing electronic cigarette (EC) use in the European Union (EU). Special Eurobarometer 429, a cross-sectional survey performed in a representative sample of 28 member states of the EU in November and December of 2014, was analyzed. The prevalence of current daily and current daily nicotine-containing EC use was 1.08% (95% CI 0.95-1.20%) and 1.00% (95% CI 0.88-1.12%), respectively, and was mainly observed in current and former smokers. Minimal current daily (0.08%, 95% CI 0.03-0.12%) and current daily nicotine-containing EC use (0.04%, 95% CI 0.01-0.08%) was observed among never smokers. Smoking cessation with the help of ECs was reported by 47.12% (95% CI 41.28-52.96%) of current daily and 49.14% (95% CI 43.12-55.17%) of current daily nicotine-containing EC users. Additionally, 33.18% (95% CI 27.67-38.69%) and 31.40% (95% CI 25.80-36.99%) reported reduction in smoking consumption, respectively. The strongest correlates of daily EC use were being current and former smokers. In the EU in late 2014, current daily EC use was predominantly observed in current and former smokers and was associated with high self-reported rates of smoking cessation and reduction. Current daily EC use by never smokers was extremely infrequent.

  12. Characterization of Near-Earth Asteroid 2009 KC3 from Radar and Thermal Infrared Observations

    NARCIS (Netherlands)

    Taylor, Patrick A.; Howell, E. S.; Nolan, M. C.; Benner, L. A. M.; Brozovic, M.; Giorgini, J. D.; Vervack, R. J.; Fernandez, Y. R.; Magri, C.; Mueller, M.

    2010-01-01

    We will report on the size, shape, spin state, and reflective and thermal properties of C-type, Apollo-class, potentially hazardous, near-Earth asteroid 2009 KC3 (a = 3.2 AU, e = 0.7, i = 10 deg). This object was discovered by the Siding Spring Survey in May 2009 and subsequently observed in the lat

  13. Weeding of Academic Library Reference Collections: A Survey of Current Practice.

    Science.gov (United States)

    Engeldinger, Eugene A.

    1986-01-01

    Reports results of survey investigating aspects of weeding of materials in reference collections at 377 U.S. colleges and universities: existence of written policy or unwritten weeding practice; extent of weeding; frequency; what happens to discards; effect of shelf space, staff time, and use of materials on weeding decisions. (5 references) (EJS)

  14. Survey on Current Conditions and Intention of Outbound Investment by Chinese Enterprises

    Institute of Scientific and Technical Information of China (English)

    China Council for the Promotion of International T

    2010-01-01

    @@ Analysis of the Sample 1.Sample size and characteristics Altogether 3000 questionnaires were distributed in the survey and 1377valid questionnaires were received,a response rate of 46%.The 1377 questionnaires recovered include enterprises in nearly 30 provinces,and cover various sectors such as agriculture,manufacturing,construction and financial intermediaries,thus providing good industrial and regional representativeness.

  15. 77 FR 58510 - Proposed Information Collection; Comment Request; Current Population Survey (CPS), Annual Social...

    Science.gov (United States)

    2012-09-21

    ... Survey (CPS), Annual Social and Economic Supplement (ASEC) AGENCY: U.S. Census Bureau, Commerce. ACTION... Annual Social and Economic Supplement (ASEC) to be conducted in conjunction with the February, March, and... casual attachment to the labor market. The income data from the ASEC are used by social...

  16. Emerging roles for biomedical librarians: a survey of current practice, challenges, and changes.

    Science.gov (United States)

    Crum, Janet A; Cooper, I Diane

    2013-10-01

    This study is intended to (1) identify emerging roles for biomedical librarians and determine how common these roles are in a variety of library settings, (2) identify barriers to taking on new roles, and (3) determine how librarians are developing the capacity to take on new roles. A survey was conducted of librarians in biomedical settings. Most biomedical librarians are taking on new roles. The most common roles selected by survey respondents include analysis and enhancement of user experiences, support for social media, support for systematic reviews, clinical informationist, help for faculty or staff with authorship issues, and implementation of researcher profiling and collaboration tools. Respondents in academic settings are more likely to report new roles than hospital librarians are, but some new roles are common in both settings. Respondents use a variety of methods to free up time for new roles, but predominant methods vary between directors and librarians and between academic and hospital respondents. Lack of time is the biggest barrier that librarians face when trying to adopt new roles. New roles are associated with increased collaboration with individuals and/or groups outside the library. This survey documents the widespread incorporation of new roles in biomedical libraries in the United States, as well as the barriers to adopting these roles and the means by which librarians are making time for them. The results of the survey can be used to inform strategic planning, succession planning, library education, and career development for biomedical librarians.

  17. The TRacking Adolescents' Individual Lives Survey (TRAILS) : Design, Current Status, and Selected Findings

    NARCIS (Netherlands)

    Ormel, Johan; Oldehinkel, Albertine J; Sijtsema, Jelle; van Oort, Floor; Raven, Dennis; Veenstra, Rene; Vollebergh, Wilma A M; Verhulst, Frank C

    2012-01-01

    Objectives: The objectives of this study were as follows: to present a concise overview of the sample, outcomes, determinants, non-response and attrition of the ongoing TRacking Adolescents' Individual Lives Survey (TRAILS), which started in 2001; to summarize a selection of recent findings on conti

  18. Current Dermatologic Care in Dutch Nursing Homes and Possible Improvements: A Nationwide Survey

    NARCIS (Netherlands)

    Lubeek, S.F.; Geer, E.R. van der; Gelder, M.M. van; Koopmans, R.T.; Kerkhof, P.C. van de; Gerritsen, M.J.

    2015-01-01

    OBJECTIVES: To assess the provision and need of dermatologic care among Dutch nursing home patients and to obtain recommendations for improvement. DESIGN: Cross-sectional nationwide survey. SETTING: All 173 nursing home organizations in the Netherlands. PARTICIPANTS: Physicians working in nursing

  19. The TRacking Adolescents' Individual Lives Survey (TRAILS) : Design, Current Status, and Selected Findings

    NARCIS (Netherlands)

    Ormel, Johan; Oldehinkel, Albertine J; Sijtsema, Jelle; van Oort, Floor; Raven, Dennis; Veenstra, Rene; Vollebergh, Wilma A M; Verhulst, Frank C

    2012-01-01

    Objectives: The objectives of this study were as follows: to present a concise overview of the sample, outcomes, determinants, non-response and attrition of the ongoing TRacking Adolescents' Individual Lives Survey (TRAILS), which started in 2001; to summarize a selection of recent findings on

  20. Spectroscopic Confusion: Its Impact on Current and Future Extragalactic HI Surveys

    CERN Document Server

    Jones, Michael G; Haynes, Martha P; Giovanelli, Riccardo

    2015-01-01

    We present a comprehensive model to predict the rate of spectroscopic confusion in HI surveys, and demonstrate good agreement with the observable confusion in existing surveys. Generically the action of confusion on the HI mass function was found to be a suppression of the number count of sources below the `knee', and an enhancement above it. This results in a bias, whereby the `knee' mass is increased and the faint end slope is steepened. For ALFALFA and HIPASS we find that the maximum impact this bias can have on the Schechter fit parameters is similar in magnitude to the published random errors. On the other hand, the impact of confusion on the HI mass functions of upcoming medium depth interferometric surveys, will be below the level of the random errors. In addition, we find that previous estimates of the number of detections for upcoming surveys with SKA-precursor telescopes may have been too optimistic, as the framework implemented here results in number counts between 60% and 75% of those previously p...

  1. Patterns in current perioperative practice: survey of colorectal surgeons in five northern European countries

    DEFF Research Database (Denmark)

    Lassen, K; Hannemann, P; Ljungqvist, O;

    2005-01-01

    no bowel preparation, epidural anaesthesia/analgesia continued for one to two days postoperatively, no nasogastric decompression tube postoperatively, intravenous fluid/saline restriction, and free oral intake from postoperative day one. 1 - 5 This survey aimed to characterise perioperative practice...

  2. The TRacking Adolescents' Individual Lives Survey (TRAILS) : Design, Current Status, and Selected Findings

    NARCIS (Netherlands)

    Ormel, Johan; Oldehinkel, Albertine J; Sijtsema, Jelle; van Oort, Floor; Raven, Dennis; Veenstra, Rene; Vollebergh, Wilma A M; Verhulst, Frank C

    2012-01-01

    Objectives: The objectives of this study were as follows: to present a concise overview of the sample, outcomes, determinants, non-response and attrition of the ongoing TRacking Adolescents' Individual Lives Survey (TRAILS), which started in 2001; to summarize a selection of recent findings on conti

  3. Generating High-Energy Events with Comets, Asteroids, and Planets

    Science.gov (United States)

    Di Stefano, Rosanne

    2015-08-01

    Many stellar remnants are likely to harbor systems of planetoids: comets, asteroids, and planets. Planetoids also travel freely through interstellar space. A combination of processes can therefore lead to tidal disruption events or collisions between planetoids and compact objects. These collisions can produce events that release a great deal of energy over a short time, and they are potentially detectable, even in external galaxies, by wide-field gamma-ray, X-ray, and optical surveys. We discuss the signatures and the possibility that these events could produce Type Ia supernovae.

  4. Why freshwater organisms survived the asteroid that killed the dinosaurs

    Science.gov (United States)

    Schultz, Colin

    2013-08-01

    Roughly 65.5 million years ago, a massive asteroid smashed into present-day Chicxulub, Mexico. The impact set fire to Earth's surface. Dust and ash darkened the sky, sending the planet into an "impact winter" that lasted months to years and caused the extinction of nonavian dinosaurs and half of ocean-dwelling species. However, life in inland freshwater ecosystems largely escaped this fate. To try to understand why freshwater organisms held on while ocean life failed, Robertson et al. surveyed relevant research to understand how the mechanisms of extinction would have operated differently in the two environments.

  5. Human Expeditions to Near-Earth Asteroids: Implications for Exploration, Resource Utilization, Science, and Planetary Defense

    Science.gov (United States)

    Abell, Paul; Mazanek, Dan; Barbee, Brent; Landis, Rob; Johnson, Lindley; Yeomans, Don; Friedensen, Victoria

    2013-01-01

    Over the past several years, much attention has been focused on human exploration of near-Earth asteroids (NEAs) and planetary defence. Two independent NASA studies examined the feasibility of sending piloted missions to NEAs, and in 2009, the Augustine Commission identified NEAs as high profile destinations for human exploration missions beyond the Earth-Moon system as part of the Flexible Path. More recently the current U.S. presidential administration directed NASA to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010. With respect to planetary defence, in 2005 the U.S. Congress directed NASA to implement a survey program to detect, track, and characterize NEAs equal or greater than 140 m in diameter in order to access the threat from such objects to the Earth. The current goal of this survey is to achieve 90% completion of objects equal or greater than 140 m in diameter by 2020.

  6. Olivine-dominated Asteroids: Mineralogy and Origin

    CERN Document Server

    Sanchez, Juan A; Kelley, Michael S; Cloutis, Edward A; Bottke, William F; Nesvorný, David; Lucas, Michael P; Hardersen, Paul S; Gaffey, Michael J; Abell, Paul A; Corre, Lucille Le

    2013-01-01

    Olivine-dominated asteroids are a rare type of objects formed either in nebular processes or through magmatic differentiation. The analysis of meteorite samples suggest that at least 100 parent bodies in the main belt experienced partial or complete melting and differentiation before being disrupted. However, only a few olivine-dominated asteroids, representative of the mantle of disrupted differentiated bodies, are known to exist. Due to the paucity of these objects in the main belt their origin and evolution have been a matter of great debate over the years. In this work we present a detailed mineralogical analysis of twelve olivine-dominated asteroids. Within our sample we distinguish two classes, one that we call pure-olivine asteroids and another referred to as olivine-rich asteroids. For the pure-olivine asteroids the olivine chemistry was found to range from ~ Fo49 to Fo70, consistent with the values measured for brachinites and R chondrites. In the case of the olivine-rich asteroids we determined thei...

  7. Target Asteroids! Observing Campaigns for April through June 2017

    Science.gov (United States)

    Hergenrother, Carl; Hill, Dolores

    2017-04-01

    Asteroid campaigns to be conducted by the Target Asteroids! program during the April-June 2017 quarter are described. In addition to asteroids on the original Target Asteroids! list of easily accessible spacecraft targets, an effort has been made to identify other asteroids that are 1) brighter and easier to observe for small telescope users and 2) analogous to (101955) Bennu and (162173) Ryugu, targets of the OSIRIS-REx and Hayabusa-2 sample return missions.

  8. Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems

    CERN Document Server

    Jacobson, Seth A

    2014-01-01

    We present a model of near-Earth asteroid (NEA) rotational fission and ensuing dynamics that describes the creation of synchronous binaries and all other observed NEA systems including: doubly synchronous binaries, high- e binaries, ternary systems, and contact binaries. Our model only presupposes the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, "rubble pile" asteroid geophysics, and gravitational interactions. The YORP effect torques a "rubble pile" asteroid until the asteroid reaches its fission spin limit and the components enter orbit about each other (Scheeres, D.J. [2007]. Icarus 189, 370-385). Non-spherical gravitational potentials couple the spin states to the orbit state and chaotically drive the system towards the observed asteroid classes along two evolutionary tracks primarily distinguished by mass ratio. Related to this is a new binary process termed secondary fission - the secondary asteroid of the binary system is rotationally accelerated via gravitational torques until it fissions, thu...

  9. A Survey of Privacy Awareness and Current Online Practices of Indian Users

    DEFF Research Database (Denmark)

    Dhotre, Prashant Shantaram; Olesen, Henning

    2015-01-01

    Today, users with their smart devices can communicate and access a wide range of services via the Internet to make their life easier. However, loss of privacy is becoming a major issue for architects or policy makers, accelerated by the rapid development of mobile and wireless technologies...... that eases the collection, storage, sharing, analysis, and manipulation of the individual’s information. The main objective of this paper is to study the privacy perception and awareness of Internet users in an Indian context. Results of comprehensive survey with 297 users are presented, focusing...... on their perception and awareness towards personal information privacy (PIP). The survey responses show that the user’s perception is noticeably low considering PIP and that the privacy awareness is not the same as their understanding. The results indicate the need for a solution for PIP protection where the users...

  10. Domestic violence perpetrator programs in Europe, Part I: A survey of current practice.

    Science.gov (United States)

    Hamilton, Leah; Koehler, Johann A; Lösel, Friedrich A

    2013-10-01

    Most research on domestic violence perpetrator programs has been carried out in North America. It does not yet provide a clear picture on what works with these offenders and cannot be generalized to other cultural and legal systems. Therefore, in Part I of this article, we present the results of a survey of 54 programs that were in place in 19 European countries that addressed the programs' practice and effects. The survey captured data about program design, delivery, administration, infrastructure, and other features. Most programs applied cognitive-behavioral, profeminist, or psychodynamic treatment, or a combination of multiple treatment types. There was a wide disparity in approaches to handling domestic violence perpetrators, and a particular dearth of high-quality evaluation throughout the continent. Possible explanations for this disparity and avenues for improvement are discussed, related to a systematic review of European outcome evaluations (Part II).

  11. Difficult cases in photometric studies of asteroids

    Science.gov (United States)

    Marciniak, Anna; Pilcher, Frederick; Oszkiewicz, Dagmara; Bartczak, Przemysław; Santana-Ros, Toni; Kamiński, Krzysztof; Urakawa, Seitaro; Ogłoza, Waldemar; Fauvaud, Stéphane; Kankiewicz, Paweł; Kudak, Viktor; Żejmo, Michał; Nishiyama, Kota; Okumura, Shin-ichiro; Nimura, Tokuhiro; Hirsch, Roman; Konstanciak, Izabella; Tychoniec, Łukasz; Figas, Michał

    2016-06-01

    We present a photometric campaign targeted at asteroids that display both long periods of rotation and small amplitudes of brightness variations. Our aim is to debias available sample of spin and shape modelled asteroids and to correct previous wrong period determinations. Our newest findings are corrected period determinations for asteroids (279) Thule (P=23.896h ± 0.005 h), (673) Edda (P=22.340h ± 0.004 h), and (737) Arequipa (P=7.0259h ± 0.0003 h). Supporting lightcurves are presented in this paper.

  12. Spectroscopy of near-Earth asteroids

    DEFF Research Database (Denmark)

    Michelsen, René; Nathues, Andreas; Lagerkvist, Claes-Ingvar

    2006-01-01

    We present spectra and taxonomic classifications of 12 Near-Earth Asteroids (NEAs) and 2 inner Main Belt asteroids. The observations were carried out with the ESO 3.5 m NTT and the Danish 1.54 m telescope at La Silla, Chile. Eleven of the investigated NEAs belong to the S class while only one C......-type has been identified. Two NEAs were observed at phase angles larger than 60 degrees introducing significant phase reddening. In order to allow for comparisons between spectra of asteroids observed at different phase angles we make attempts to correct for this effect. However, it turned out...

  13. Spectroscopy of near-Earth asteroids

    DEFF Research Database (Denmark)

    Michelsen, René; Nathues, Andreas; Lagerkvist, Claes-Ingvar

    2006-01-01

    We present spectra and taxonomic classifications of 12 Near-Earth Asteroids (NEAs) and 2 inner Main Belt asteroids. The observations were carried out with the ESO 3.5 m NTT and the Danish 1.54 m telescope at La Silla, Chile. Eleven of the investigated NEAs belong to the S class while only one C......-type has been identified. Two NEAs were observed at phase angles larger than 60 degrees introducing significant phase reddening. In order to allow for comparisons between spectra of asteroids observed at different phase angles we make attempts to correct for this effect. However, it turned out...

  14. Solar Radiation and Near-Earth Asteroids: Thermophysical Modeling and New Measurements of the Yarkovsky Effect

    Science.gov (United States)

    Nugent, Carolyn Rosemary

    This dissertation examines the influence of solar radiation on near-Earth asteroids (NEAs); it investigates thermal properties and examines changes to orbits caused by the process of anisotropic re-radiation of sunlight called the Yarkovsky effect. For the first portion of this dissertation, we used geometric albedos pV and diameters derived from the Wide-Field Infrared Survey Explorer (WISE), as well as geometric albedos and diameters from the literature, to produce more accurate diurnal Yarkovsky drift predictions for 540 NEAs out of the current sample of ˜8800 known objects. These predictions are intended to assist observers, and should enable future Yarkovsky detections. The second portion of this dissertation introduces a new method for detecting the Yarkovsky drift. We identified and quantified semi-major axis drifts in NEAs by performing orbital fits to optical and radar astrometry of all numbered NEAs. We discuss a subset of 54 NEAs that exhibit some of the most reliable and strongest drift rates. Our selection criteria include a Yarkovsky sensitivity metric that quantifies the detectability of semi-major axis drift in any given data set, a signal-to-noise metric, and orbital coverage requirements. In 42 cases, the observed drifts (˜ 10-3 AU/Myr) agree well with numerical estimates of Yarkovsky drifts. This agreement suggests that the Yarkovsky effect is the dominant non-gravitational process affecting these orbits, and allows us to derive constraints on asteroid physical properties. We define the Yarkovsky efficiency fY as the ratio of the change in orbital energy to incident solar radiation energy, and we find that typical Yarkovsky efficiencies are ˜10-5. The final portion of this dissertation describes the development of and results from a detailed thermal model of potentially hazardous asteroid (29075) 1950 DA. This model combines radar-derived shape models of the object and fourteen 12 micron observations by the WISE spacecraft. The observations

  15. Asteroids@home - A BOINC distributed computing project for asteroid shape reconstruction

    CERN Document Server

    Durech, Josef; Vanco, Radim

    2015-01-01

    We present the project Asteroids@home that uses distributed computing to solve the time-consuming inverse problem of shape reconstruction of asteroids. The project uses the Berkeley Open Infrastructure for Network Computing (BOINC) framework to distribute, collect, and validate small computational units that are solved independently at individual computers of volunteers connected to the project. Shapes, rotational periods, and orientations of the spin axes of asteroids are reconstructed from their disk-integrated photometry by the lightcurve inversion method.

  16. Initial sizes of planetesimals and accretion of the asteroids

    Science.gov (United States)

    Weidenschilling, S. J.

    2011-08-01

    The present size frequency distribution (SFD) of bodies in the asteroid belt appears to have preserved some record of the primordial population, with an excess of bodies of diameter D ˜ 100 km relative to a simple power law. The survival of Vesta's basaltic crust also implies that the early SFD had a shallow slope in the range ˜10-100 km. (Morbidelli, A., Bottke, W.F., Nesvorny, D., Levison, H.F. [2009]. Icarus 204, 558-573) were unable to produce these features by accretion from an initial population of km-sized planetesimals. They concluded that bodies with sizes in the range ˜100-1000 km and a SFD similar to the current population were produced directly from solid particles of sub-meter scale, without experiencing accretion through intermediate sizes. We present results of new accretion simulations in the primordial asteroid region. The requisite SFD can be produced from an initial population of planetesimals of sizes ≲0.1 km, smaller than the usual assumption of km-sized bodies. The bump at D ˜ 100 km is produced by a transition from dispersion-dominated runaway growth to a regime dominated by Keplerian shear, before the formation of large protoplanetary embryos. Thus, accretion of the asteroids from an initial population of small (sub-km) planetesimals cannot be ruled out.

  17. An anisotropic distribution of spin vectors in asteroid families

    CERN Document Server

    Hanuš, J; Ďurech, J; Warner, B D; Brinsfield, J; Durkee, R; Higgins, D; Koff, R A; Oey, J; Pilcher, F; Stephens, R; Strabla, L P; Ulisse, Q; Girelli, R

    2013-01-01

    Current amount of ~500 asteroid models derived from the disk-integrated photometry by the lightcurve inversion method allows us to study not only the spin-vector properties of the whole population of MBAs, but also of several individual collisional families. We create a data set of 152 asteroids that were identified by the HCM method as members of ten collisional families, among them are 31 newly derived unique models and 24 new models with well-constrained pole-ecliptic latitudes of the spin axes. The remaining models are adopted from the DAMIT database or the literature. We revise the preliminary family membership identification by the HCM method according to several additional criteria - taxonomic type, color, albedo, maximum Yarkovsky semi-major axis drift and the consistency with the size-frequency distribution of each family, and consequently we remove interlopers. We then present the spin-vector distributions for eight asteroidal families. We use a combined orbital- and spin-evolution model to explain ...

  18. An integrated view of asteroid regeneration: tissues, cells and molecules.

    Science.gov (United States)

    Ben Khadra, Yousra; Sugni, Michela; Ferrario, Cinzia; Bonasoro, Francesco; Varela Coelho, Ana; Martinez, Pedro; Candia Carnevali, Maria Daniela

    2017-03-22

    The potential for repairing and replacing cells, tissues, organs and body parts is considered a primitive attribute of life shared by all the organisms, even though it may be expressed to a different extent and which is essential for the survival of both individual and whole species. The ability to regenerate is particularly evident and widespread within invertebrates. In spite of the wide availability of experimental models, regeneration has been comprehensively explored in only a few animal systems (i.e., hydrozoans, planarians, urodeles) leaving many other animal groups unexplored. The regenerative potential finds its maximum expression in echinoderms. Among echinoderm classes, asteroids offer an impressive range of experimental models in which to study arm regeneration at different levels. Many studies have been recently carried out in order to understand the regenerative mechanisms in asteroids and the overall morphological processes have been well documented in different starfish species, such as Asterias rubens, Leptasterias hexactis and Echinaster sepositus. In contrast, very little is known about the molecular mechanisms that control regeneration development and patterning in these models. The origin and the fate of cells involved in the regenerative process remain a matter of debate and clear insights will require the use of complementary molecular and proteomic approaches to study this problem. Here, we review the current knowledge regarding the cellular, proteomic and molecular aspects of asteroid regeneration.

  19. Hayabusa 2 extension plan: Asteroid selection and trajectory design

    Science.gov (United States)

    Sarli, Bruno Victorino; Tsuda, Yuichi

    2017-09-01

    The Hayabusa 2 mission is targeted to explore the asteroid (162173) 1999 JU3 and return surface as well as sub-surface samples through a novel impactor. Upon its return, at the end of 2020, the spacecraft will release the capsule for Earth re-entry and drift away from the planet. Based on the current mission profile, the spacecraft is expected to retain 30 kg of xenon propellant for trajectory maneuvers after the capsule is released. This remaining fuel can be used to extend the mission and improve its scientific return by exploring a new target. Work herein outlines an extension plan for Hayabusa 2, detailing the target selection process and its subsequent trajectory design. Due to final Earth escape trajectory, considering the excess velocity and orbital geometry, the only available extension option is an asteroid flyby. One of the most important trajectory characteristic is to maximize the spacecraft's optical detection capabilities. As a result the asteroid 2001 WR1 is identified as the most promising target candidate. The resulting trajectory uses all the available xenon with 100% duty cycle. Furthermore, the extension lasts for 932 days and offers 1.57 days of optical navigation time for a flyby on June 27, 2023.

  20. Acellular Dermal Matrix in Reconstructive Breast Surgery: Survey of Current Practice among Plastic Surgeons

    Directory of Open Access Journals (Sweden)

    Ahmed M. S. Ibrahim, MD

    2015-04-01

    Conclusions: Plastic surgeons currently use ADM in breast reconstruction for both immediate and staged procedures. Of those responding, a majority of plastic surgeons will incorporate drains and use postoperative antibiotics for more than 48 hours.

  1. New and updated convex shape models of asteroids based on optical data from a large collaboration network

    CERN Document Server

    Hanuš, J; Oszkiewicz, D A; Behrend, R; Carry, B; Delbo', M; Adam, O; Afonina, V; Anquetin, R; Antonini, P; Arnold, L; Audejean, M; Aurard, P; Bachschmidt, M; Badue, B; Barbotin, E; Barroy, P; Baudouin, P; Berard, L; Berger, N; Bernasconi, L; Bosch, J-G; Bouley, S; Bozhinova, I; Brinsfield, J; Brunetto, L; Canaud, G; Caron, J; Carrier, F; Casalnuovo, G; Casulli, S; Cerda, M; Chalamet, L; Charbonnel, S; Chinaglia, B; Cikota, A; Colas, F; Coliac, J-F; Collet, A; Coloma, J; Conjat, M; Conseil, E; Costa, R; Crippa, R; Cristofanelli, M; Damerdji, Y; Debackere, A; Decock, A; Déhais, Q; Déléage, T; Delmelle, S; Demeautis, C; Dróżdż, M; Dubos, G; Dulcamara, T; Dumont, M; Durkee, R; Dymock, R; del Valle, A Escalante; Esseiva, N; Esseiva, R; Esteban, M; Fauchez, T; Fauerbach, M; Fauvaud, M; Fauvaud, S; Forné, E; Fournel, C; Fradet, D; Garlitz, J; Gerteis, O; Gillier, C; Gillon, M; Giraud, R; Godard, J-P; Goncalves, R; Hamanowa, H; Hamanowa, H; Hay, K; Hellmich, S; Heterier, S; Higgins, D; Hirsch, R; Hodosan, G; Hren, M; Hygate, A; Innocent, N; Jacquinot, H; Jawahar, S; Jehin, E; Jerosimic, L; Klotz, A; Koff, W; Korlevic, P; Kosturkiewicz, E; Krafft, P; Krugly, Y; Kugel, F; Labrevoir, O; Lecacheux, J; Lehký, M; Leroy, A; Lesquerbault, B; Lopez-Gonzales, M J; Lutz, M; Mallecot, B; Manfroid, J; Manzini, F; Marciniak, A; Martin, A; Modave, B; Montaigut, R; Montier, J; Morelle, E; Morton, B; Mottola, S; Naves, R; Nomen, J; Oey, J; Ogłoza, W; Paiella, M; Pallares, H; Peyrot, A; Pilcher, F; Pirenne, J-F; Piron, P; Polinska, M; Polotto, M; Poncy, R; Previt, J P; Reignier, F; Renauld, D; Ricci, D; Richard, F; Rinner, C; Risoldi, V; Robilliard, D; Romeuf, D; Rousseau, G; Roy, R; Ruthroff, J; Salom, P A; Salvador, L; Sanchez, S; Santana-Ros, T; Scholz, A; Séné, G; Skiff, B; Sobkowiak, K; Sogorb, P; Soldán, F; Spiridakis, A; Splanska, E; Sposetti, S; Starkey, D; Stephens, R; Stiepen, A; Stoss, R; Strajnic, J; Teng, J-P; Tumolo, G; Vagnozzi, A; Vanoutryve, B; Vugnon, J M; Warner, B D; Waucomont, M; Wertz, O; Winiarski, M; Wolf, M

    2015-01-01

    Asteroid modeling efforts in the last decade resulted in a comprehensive dataset of almost 400 convex shape models and their rotation states. This amount already provided a deep insight into physical properties of main-belt asteroids or large collisional families. We aim to increase the number of asteroid shape models and rotation states. Such results are an important input for various further studies such as analysis of asteroid physical properties in different populations, including smaller collisional families, thermophysical modeling, and scaling shape models by disk-resolved images, or stellar occultation data. This provides, in combination with known masses, bulk density estimates, but constrains also theoretical collisional and evolutional models of the Solar System. We use all available disk-integrated optical data (i.e., classical dense-in-time photometry obtained from public databases and through a large collaboration network as well as sparse-in-time individual measurements from a few sky surveys) ...

  2. The First Results of the Photometric Observation of Selected Asteroids on KT-50 Telescope of Mobitel Complex of RI MAO

    Directory of Open Access Journals (Sweden)

    Pomazan, A.V.

    2017-01-01

    Full Text Available The first results of the photometric observations of asteroids performed on the telescope KT-50 of Mobitel complex (SRI MAO during 2016 are presented in the paper. Asteroids were selected based on the infrared survey NEOWISE, moving objects catalog SDSS MOC-3 and MPC database. Selected asteroids have a relatively high albedo (pV>0.2 and are located in the Outer Main Belt (semi-major axis a>0.28a.u.. The observations were made using filter close to the Rc standard band of Cousins system. Standard deviations of the instrumental differential magnitude measurements were in the range of 0.01m-0.03m for a 10m-15.5m reference stars. The light curve based on the results of the differential aperture photometry was obtained from long series of observations of the asteroid (2144 Marietta.

  3. Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems

    Science.gov (United States)

    Jacobson, Seth A.; Scheeres, Daniel J.

    2011-07-01

    We present a model of near-Earth asteroid (NEA) rotational fission and ensuing dynamics that describes the creation of synchronous binaries and all other observed NEA systems including: doubly synchronous binaries, high- e binaries, ternary systems, and contact binaries. Our model only presupposes the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, "rubble pile" asteroid geophysics, and gravitational interactions. The YORP effect torques a "rubble pile" asteroid until the asteroid reaches its fission spin limit and the components enter orbit about each other (Scheeres, D.J. [2007]. Icarus 189, 370-385). Non-spherical gravitational potentials couple the spin states to the orbit state and chaotically drive the system towards the observed asteroid classes along two evolutionary tracks primarily distinguished by mass ratio. Related to this is a new binary process termed secondary fission - the secondary asteroid of the binary system is rotationally accelerated via gravitational torques until it fissions, thus creating a chaotic ternary system. The initially chaotic binary can be stabilized to create a synchronous binary by components of the fissioned secondary asteroid impacting the primary asteroid, solar gravitational perturbations, and mutual body tides. These results emphasize the importance of the initial component size distribution and configuration within the parent asteroid. NEAs may go through multiple binary cycles and many YORP-induced rotational fissions during their approximately 10 Myr lifetime in the inner Solar System. Rotational fission and the ensuing dynamics are responsible for all NEA systems including the most commonly observed synchronous binaries.

  4. ASIME 2016 White Paper: In-Space Utilisation of Asteroids: "Answers to Questions from the Asteroid Miners"

    OpenAIRE

    Graps, Amara L.; Blondel, Philippe; Bonin, Grant; Britt, Daniel; Centuori, Simone; Delbo, Marco; Drube, Line; Duffard, Rene; Elvis, Martin; Faber, Daniel; Frank, Elizabeth; Galache, JL; Green, Simon F.; Grundmann, Jan Thimo; Hsieh, Henry

    2016-01-01

    The aim of the Asteroid Science Intersections with In-Space Mine Engineering (ASIME) 2016 conference on September 21-22, 2016 in Luxembourg City was to provide an environment for the detailed discussion of the specific properties of asteroids, with the engineering needs of space missions that utilize asteroids. The ASIME 2016 Conference produced a layered record of discussions from the asteroid scientists and the asteroid miners to understand each other's key concerns and to address key scien...

  5. Water in Asteroid 4 Vesta

    Science.gov (United States)

    Taylor, G. J.

    2015-01-01

    Eucrite meteorites come from asteroid 4 Vesta, which was recently studied from orbit by NASA's Dawn mission. Adam Sarafian (Woods Hole Oceanographic Institute) and colleagues at Woods Hole, the University of Bristol, England, and the University of New Mexico measured the hydrogen concentration and deuterium/hydrogen (D/H) ratio in crystals of the mineral apatite (calcium phosphate) in eucrites. They found that the D/H ratio is in the same range as in carbonaceous chondrites, most samples of the Earth's mantle, and in samples of basaltic meteorites from Mars. Combined with measurements of the isotopic compositions of nitrogen and carbon, the data suggest that these volatile elements were added to Earth early in its history, probably during its formation. Other studies conclude that water with D/H like that in carbonaceous chondrites, Earth, Mars, and Vesta were likely inherited from interstellar ice that predates formation of the solar system.

  6. Comets, Asteroids and Rubble Piles: not just debris

    Science.gov (United States)

    Harold, J. B.; Dusenbery, P.

    2010-12-01

    The National Center for Interactive Learning at the Space Science Institute (NCIL @ SSI) is developing a variety of asteroids related education activities as part of several E/PO projects, including Finding NEO (funded through NSF and NASA SMD); Great Balls of Fire! (funded through NSF); and a partnership with the WISE (Wide-field Infrared Survey Explorer) mission. These activities range from a web site to traveling exhibits in three different sizes. The Killer Asteroids web site (www.killerasteroids.org) includes background information on comets and asteroids as well as a number of interactive activities and games. These include a game that compares the risk of death from an asteroid impact to other hazards; a game and video vignettes on the role of backyard astronomers in light curve research; a physics-based asteroid deflection game; and a Google Earth -based "drop a rock on your house" activity. In addition, the project is developing a small, portable exhibit suitable for use in libraries or visitors centers. Great Balls of Fire! includes two separate traveling exhibitions: a 3000 square foot exhibition for science centers, and a 500 square foot version for smaller venues. Both will begin national tours in the summer of 2011. The Great Balls of Fire! exhibit program includes a free Education Program for docents and educators, and an Outreach Program to amateur astronomers around the country through the Astronomical Society of the Pacific’s (ASP) Astronomy from the Ground Up program. The project will facilitate partnerships between host venues and local astronomy clubs that can interact with the public using a toolkit of activities developed by ASP. Great Balls of Fire! Represents a collaboration between scientists, educators, exhibit designers, graphic artists, evaluators, education researchers, and three teams of middle school students who acted as advisors. The project’s exhibit design firm is Jeff Kennedy Associates Inc. We will present a summary of the

  7. The WiFeS S7 AGN survey: Current status and recent results on NGC 6300

    CERN Document Server

    Scharwächter, J; Shastri, P; Davies, R; Kewley, L; Hampton, E; Sutherland, R; Kharb, P; Jose, J; Bhatt, H; Ramya, S; Jin, C; Banfield, J; Zaw, I; Juneau, S; James, B; Srivastava, S

    2015-01-01

    The Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) is a targeted survey probing the narrow-line regions (NLRs) of a representative sample of ~140 nearby (z<0.02) Seyfert galaxies by means of optical integral field spectroscopy. The survey is based on a homogeneous data set observed using the Wide Field Spectrograph WiFeS. The data provide a 25x38 arcsec$^2$ field-of-view around the galaxy centre at typically ~1.5 arcsec spatial resolution and cover a wavelength range between ~3400 - 7100 $\\AA$ at spectral resolutions of ~100 km s$^{-1}$ and ~50 km s$^{-1}$ in the blue and red parts, respectively. The survey is primarily designed to study gas excitation and star formation around AGN, with a special focus on the shape of the AGN ionising continuum, the interaction between radio jets and the NLR gas, and the nature of nuclear LINER emission. We provide an overview of the current status of S7-based results and present new results for NGC 6300.

  8. A survey of the current use of neuromuscular blocking drugs among the Middle Eastern anesthesiologists

    Directory of Open Access Journals (Sweden)

    Abdelazeem Eldawlatly

    2013-01-01

    Full Text Available Background: This survey aimed to assess the extent of practice of the Middle Eastern anesthesiologists in the use of neuromuscular blocking agents (NMB in 2012. Methods: We distributed an electronic survey among 577 members of the Triple-M Middle Eastern Yahoo anesthesia group, enquiring about their practice in the use of neuromuscular blocking agents. Questions concerned the routine "first choice" use of NMB, choice for tracheal intubation, the use of neuromuscular monitoring (NMT, type of NMB used in difficult airway, frequency of using suxamethonium, cisatracurium, rocuronium and sugammadex, observed side effects of rocuronium, residual curarization, and the reversal of residual curarization of rocuronium. Results: A total of 71 responses from 22 Middle Eastern institutions were collected. Most of the Middle Eastern anesthesiologists were using cisatracurium and rocuronium frequently for tracheal intubation (39% and 35%, respectively. From the respondents, 2/3 were using suxamethonium for tracheal intubation in difficult airway, 1/3 were using rocuronium routinely and 17% have observed hypersensitivity reactions to rocuronium, 54% reported residual curarization from rocuronium, 78% were routinely using neostigmine to reverse the rocuronium, 21% used sugammadex occasionally, and 35% were using NMT routinely during the use of NMB. Conclusions: We believe that more could be done to increase the awareness of the Middle Eastern anesthesiologists about the high incidence of PROC (>20% and the need for routine monitoring of neuromuscular function. This could be accomplished with by developing formal training programs and providing official guidelines.

  9. [Survey of current conditions regarding awareness of the nutritional role of supplements for pharmacy students].

    Science.gov (United States)

    Shimizu, Rumiko; Sakamoto, Youko; Nishizawa, Tomoko; Iguchi, Shin; Yamaoka, Yumiko

    2007-09-01

    Various nutritional supplements have become available in recent years. However, health problems resulting from the misuse of these supplements are on the rise, and have been attributed to a lack of knowledge among consumers. In addition, a survey of university students revealed that approximately 20% of students erroneously considered nutritionally balanced supplements as substitutes for meals. Given this background, we conducted a questionnaire survey of first- and fourth-year students at the Faculty of Pharmaceutical Sciences at Kobe Gakuin University with the objective of elucidating factors such as the awareness of supplements among pharmacy students and whether these students had a superior understanding of supplements compared to the general student population. Awareness of supplements among students was determined in terms of the degrees of emphasis on meals and supplements in nutritional intake. The proportion of students who essentially believed that "nutritionally balanced supplements can be used as substitutes for meals" did not significantly differ between pharmacy students and the general student population. In addition, only 30% of students had an accurate understanding of supplements. Following graduation, pharmacy students may become pharmacists and thus be responsible for providing directions regarding usage of supplements. These findings suggest that in order to nurture professional pharmacists, it is necessary to first implement practical nutrition education and consumer education to promote healthier dietary habits among the students themselves.

  10. Current status of obstetrics and gynecology resident medical-legal education: a survey of program directors.

    Science.gov (United States)

    Moreno-Hunt, Carey; Gilbert, William M

    2005-12-01

    To assess the level and type of medical-legal education offered to obstetrics and gynecology residents and medical students. All obstetrics and gynecology program directors (n = 252) were asked to complete a survey questioning the availability of, type of, and desire for medical-legal education within their programs. Seventy-eight percent of the program directors answered the survey with 86% reporting some degree of formal medical-legal education. The most common formats were didactic lectures (38%), grand rounds (30%), case conferences (19%), mock trials (9%), and other (4%). These sessions most commonly contained information on proper documentation (48%), testifying (25%), and giving a deposition (24%). The average number of sessions per year was 4.1 with a median of 3 sessions per year. Despite this high percentage of some formal education, 88% expressed an interest in pursuing other educational options on these topics. Most obstetrics and gynecology residency programs provide some form of medical-legal instruction to residents, but the small number of sessions suggests that this is inadequate. Residency programs may benefit from a larger and more formal resident education program on medical-legal issues.

  11. [Current status of non-invasive ventilation in German ICU's -- a postal survey].

    Science.gov (United States)

    Kumle, B; Haisch, G; Suttner, S W; Piper, S N; Maleck, W; Boldt, J

    2003-01-01

    The status of non-invasive ventilation (NIV) in intensive care units (ICU) in Germany was analysed by a national survey. Questionnaires consisting of multiple-choice and short-answer questions were sent to ICUs of university hospitals, hospitals with >1000 beds, with 500 - 1000 beds, and hospitals with pneumonia (64 %), pulmonary oedema (50 %), bronchial asthma (35 %) and ALI/ARDS (22 %). The use of NIV was considered when clinical signs of ventilation (93 %) and oxygenation [arterial blood gas analysis (92 %) and oxygen saturation (66 %)] were inadequate. Complications observed during NIV were panic reaction (83 %), ulceration of nose (38 %) and aspiration (14 %). The reasons to reject NIV were (total 13 %): lack of ventilators (64 %), expenditure of personnel (57 %) and risk of the procedure (11 %). 38 % of the ventilators used were older than 5 years. 56 % of the ICUs were content with the equipment for NIV. 76 % of the ICUs were interested to buy new equipment of NIV. 99 % of the survey have declined NIV as an alternative method of ventilation. In summary we found NIV as an accepted additional method of ventilatory support in respiratory failure in German ICUs. We found no significant increase in frequency of NIV in the last three years.

  12. Assessment of surgical competence in North American graduate periodontics programs: a survey of current practices.

    Science.gov (United States)

    Ghiabi, Edmond; Taylor, K Lynn

    2010-08-01

    This cross-sectional study was designed to document the methods utilized by North American graduate periodontics programs in assessing their residents' surgical skills. A survey of clinical skills assessment was mailed to directors of all fifty-eight graduate periodontics programs in Canada and the United States. Thirty-four programs (59 percent) responded. The data collected were analyzed using SPSS version 15.0. The results demonstrate that the most common practice for providing feedback and documenting residents' surgical skills in the programs surveyed was daily one-on-one verbal feedback given by an instructor. The next two most commonly reported methods were a standard checklist developed at program level and a combination of a checklist and verbal comments. The majority of the programs reported that the instructors met collectively once per term to evaluate the residents' progress. The results suggest that graduate periodontics programs provide their residents frequent opportunities for daily practice with verbal feedback from instructors. However, assessment strategies identified in other health professions as beneficial in fostering the integration of clinical skills practices are not employed.

  13. Neuroimaging training among neuropsychologists: a survey of the state of current training and recommendations for trainees.

    Science.gov (United States)

    Benitez, Andreana; Hassenstab, Jason; Bangen, Katherine J

    2014-01-01

    Neuroimaging has gained widespread use in neuropsychological research and practice. However, there are neither established guidelines on how neuropsychologists might become competent researchers or consumers of neuroimaging data, nor any published studies describing the state of neuroimaging training among neuropsychologists. We report the results of two online surveys, one of 13 expert neuropsychologist-neuroimagers whose responses informed the formulation of a second, larger survey to neuropsychologists-at-large that were a random selection of a third of the members of the International Neuropsychological Society and American Academy of Clinical Neuropsychology. A total of 237 doctoral-level neuropsychologists, or 15.3% of potential participants, provided complete responses. Most respondents (69.2%) received training in neuroimaging, mostly at the post-doctoral level, largely through independent study, clinical conferences, instruction by clinical supervisors, and individualized mentoring, on topics such as neuroimaging modalities in neurology, neuroanatomy, and the appropriate information to glean from neuroradiology reports. Of the remaining respondents who did not receive training in neuroimaging, 64.4% indicated that such training would be very or extremely beneficial to one's career as a neuropsychologist. Both neuropsychologist-neuroimagers and neuropsychologists-at-large provided specific recommendations for training. Findings from this initial effort will guide trainees who seek to develop competence in neuroimaging, and inform future formulations of neuropsychological training.

  14. Chelyabinsk: Portrait of an asteroid airburst

    Energy Technology Data Exchange (ETDEWEB)

    Kring, David A.; Boslough, Mark

    2014-09-01

    Video and audio from hundreds of smartphones and dashboard cameras combined with seismic, acoustic, and satellite measurements provide the first precise documentation of a 10 000-ton asteroid explosion.

  15. Jupiter Magnetospheric Orbiter and Trojan Asteroid Explorer in EJSM

    Science.gov (United States)

    Sasaki, Sho; Fujimoto, Masaki; Yano, Hajime; Takashima, Takeshi; Kasaba, Yasumasa; Funase, Ryu; Tsuda, Yuichi; Kawaguchi, Junichiro; Kawakatsu, Yasuhiro; Mori, Osamu; Morimoto, Mutsuko; Yoshida, Fumi; Takato, Naruhisa

    The international mission to explore the Jovian system is planned as Europa Jupiter System Mission (EJSM) aiming at the launch in 2020. EJSM consists of (1) the Jupiter Europa Orbiter (JEO) by NASA, (2) the Jupiter Ganymede Orbiter (JGO) by ESA, and (3) the Jupiter Magnetospheric Orbiter (JMO) studied by JAXA (Japan Aerospace Exploration Agency). In February 2009, NASA and ESA decided to continue the study of EJSM as a candidate of the outer solar system mission. In JAXA, a mission plan combining Trojan asteroid explorer with JMO started. According to the mission plan, as the main spacecraft flies by Jupiter, it will deploy the JMO satellite around Jupiter. Then the main will target one (or two) Trojan asteroids. JMO is a spin-stabilized satellite which will have magnetometers, low-energy plasma spectrome-ters, medium energy particle detectors, energetic particle detectors, electric field / plasma wave instruments, an ENA imager, an EUV spectrometer, and a dust detector. Collaborating with plasma instruments on board JEO and JGO, JMO will investigate the fast-rotating huge mag-netosphere to clarify the energy procurement from the rotation of Jupiter to the magnetosphere and to clarify the interaction between the solar wind and the magnetosphere. JAXA started the study of a solar power sail for deep space explorations. In addition to the function of a solar sail (photon propulsion), the solar power sail system has very efficient ion engines where electric power is produced solar panels within the sail. Currently we are studying a mission to Jupiter and Trojan asteroids using a large (100m-scale) solar power sail that can transfer large payload as far as Jupiter. Trojan asteroids, which orbit around Jupiter's Lagrangian points, are primitive bodies with information of the early solar system as well as raw solid materials of Jovian system. Proposed instruments for the Trojan spacecraft are cameras, IR spectrometers, XRS, a laser altimeter, and a small surface rover

  16. An Early Warning System for Asteroid Impact

    Science.gov (United States)

    Tonry, John L.

    2011-01-01

    Earth is bombarded by meteors, occasionally by one large enough to cause a significant explosion and possible loss of life. It is not possible to detect all hazardous asteroids, and the efforts to detect them years before they strike are only advancing slowly. Similarly, ideas for mitigation of the danger from an impact by moving the asteroid are in their infancy. Although the odds of a deadly asteroid strike in the next century are low, the most likely impact is by a relatively small asteroid, and we suggest that the best mitigation strategy in the near term is simply to move people out of the way. With enough warning, a small asteroid impact should not cause loss of life, and even portable property might be preserved. We describe an early warning system that could provide a week’s notice of most sizeable asteroids or comets on track to hit the Earth. This may be all the mitigation needed or desired for small asteroids, and it can be implemented immediately for relatively low cost. This system, dubbed Asteroid Terrestrial-Impact Last Alert System (ATLAS), comprises two observatories separated by about 100 km that simultaneously scan the visible sky twice a night. Software automatically registers a comparison with the unchanging sky and identifies everything that has moved or changed. Communications between the observatories lock down the orbits of anything approaching the Earth, within one night if its arrival is less than a week. The sensitivity of the system permits detection of 140 m asteroids (100 Mton impact energy) three weeks before impact and 50 m asteroids a week before arrival. An ATLAS alarm, augmented by other observations, should result in a determination of impact location and time that is accurate to a few kilometers and a few seconds. In addition to detecting and warning of approaching asteroids, ATLAS will continuously monitor the changing universe around us: most of the variable stars in our Galaxy, many microlensing events from stellar

  17. Modelling asteroid brightness variations. I - Numerical methods

    Science.gov (United States)

    Karttunen, H.

    1989-01-01

    A method for generating lightcurves of asteroid models is presented. The effects of the shape of the asteroid and the scattering law of a surface element are distinctly separable, being described by chosen functions that can easily be changed. The shape is specified by means of two functions that yield the length of the radius vector and the normal vector of the surface at a given point. The general shape must be convex, but spherical concavities producing macroscopic shadowing can also be modeled.

  18. Olivine-dominated asteroids: Mineralogy and origin

    OpenAIRE

    Sanchez, Juan A.; Reddy, Vishnu; Kelley, Michael S.; Cloutis, Edward A.; Bottke, William F.; Nesvorný, David; Lucas, Michael P.; Hardersen, Paul S.; Gaffey, Michael J.; Abell, Paul A.; Corre, Lucille Le

    2013-01-01

    Olivine-dominated asteroids are a rare type of objects formed either in nebular processes or through magmatic differentiation. The analysis of meteorite samples suggest that at least 100 parent bodies in the main belt experienced partial or complete melting and differentiation before being disrupted. However, only a few olivine-dominated asteroids, representative of the mantle of disrupted differentiated bodies, are known to exist. Due to the paucity of these objects in the main belt their or...

  19. Engineering change management report 2012: Survey results on causes and effects, current practice, problems, and strategies in Brazil

    DEFF Research Database (Denmark)

    Chucholowski, Nepomuk; Langer, Stefan; Ferreira, Marcelo Gitirana Gomes

    management of engineering changes is a crucial precondition for Brazilian companies to successfully compete not only on the fast growing Brazilian market, but also on the world market which becomes more interesting due to the rising industrial power of Brazil. To achieve improvements in engineering change...... management practice, industry and universities need to work together. In this report the main findings of our study on Engineering Change Management (ECM) in Brazilian companies are presented, which indicate possible solution strategies and further research needs. Our survey aimed on the investigation...... of current practice, the biggest challenges and potential strategies of engineering change management. A total of 55 Brazilian companies from a broad range of industry sectors and company sizes participated from December 2011 until January 2012 in the survey which was elaborated and conducted by members...

  20. The Asteroid Belt as a Relic From a Chaotic Early Solar System

    CERN Document Server

    Izidoro, Andre; Pierens, Arnaud; Morbidelli, Alessandro; Winter, Othon C; Nesvorny, David

    2016-01-01

    The orbital structure of the asteroid belt holds a record of the Solar System's dynamical history. The current belt only contains ${\\rm \\sim 10^{-3}}$ Earth masses yet the asteroids' orbits are dynamically excited, with a large spread in eccentricity and inclination. In the context of models of terrestrial planet formation, the belt may have been excited by Jupiter's orbital migration. The terrestrial planets can also be reproduced without invoking a migrating Jupiter; however, as it requires a severe mass deficit beyond Earth's orbit, this model systematically under-excites the asteroid belt. Here we show that the orbits of the asteroids may have been excited to their current state if Jupiter and Saturn's early orbits were chaotic. Stochastic variations in the gas giants' orbits cause resonances to continually jump across the main belt and excite the asteroids' orbits on a timescale of tens of millions of years. While hydrodynamical simulations show that the gas giants were likely in mean motion resonance at...

  1. Surveys of current status in biomedical science grant review: funding organisations' and grant reviewers' perspectives

    DEFF Research Database (Denmark)

    Schroter, Sara; Groves, Trish; Højgaard, Liselotte

    2010-01-01

    The objectives of this research were (a) to describe the current status of grant review for biomedical projects and programmes from the perspectives of international funding organisations and grant reviewers, and (b) to explore funders' interest in developing uniform requirements for grant review...... aimed at making the processes and practices of grant review more consistent, transparent, and user friendly....

  2. Current Evaluation of Upper Oesophageal Sphincter Opening in Dysphagia Practice: An International SLT Survey

    Science.gov (United States)

    Regan, Julie; Walshe, Margaret; McMahon, Barry P.

    2012-01-01

    Background: The assessment of adequate upper oesophageal sphincter (UOS) opening during swallowing is an integral component of dysphagia evaluation. Aims: To ascertain speech and language therapists' (SLTs) satisfaction with current methods for assessing UOS function in people with dysphagia and to identify challenges encountered by SLTs with UOS…

  3. Experimental Results on Current-Driven Turbulence in Plasmas - a Survey

    NARCIS (Netherlands)

    Dekluiver, H.; Perepelkin, N. F.; Hirose, A.

    1991-01-01

    The experimental consequences of plasma turbulence driven by a current parallel to a magnetic field and concurrent anomalous plasma heating are reviewed, with an attempt to deduce universalities in key parameters such as the anomalous electrical conductivities observed in diverse devices. It has

  4. Surveys of current status in biomedical science grant review: funding organisations' and grant reviewers' perspectives

    DEFF Research Database (Denmark)

    Schroter, Sara; Groves, Trish; Højgaard, Liselotte

    2010-01-01

    The objectives of this research were (a) to describe the current status of grant review for biomedical projects and programmes from the perspectives of international funding organisations and grant reviewers, and (b) to explore funders' interest in developing uniform requirements for grant review...

  5. Current practices in the management of malignant pleural effusions: a survey among members of the European Society of Thoracic Surgeons.

    Science.gov (United States)

    Scarci, Marco; Caruana, Edward; Bertolaccini, Luca; Bedetti, Benedetta; Brunelli, Alessandro; Varela, Gonzalo; Papagiannopoulos, Kostas; Kuzdzal, Jaroslaw; Massard, Gilbert; Ruffini, Enrico; Falcoz, Pierre Emmanuel; Opitz, Isabelle; Batirel, Hasan; Toker, Alper; Rocco, Gaetano

    2017-03-01

    Malignant pleural effusion (MPE) commonly complicates advanced malignancy and their exact management is still undefined. We undertook a survey to determine the current practice among members of the European Society of Thoracic Surgeons (ESTS). A cross-sectional survey focused on the current practice of management of MPE was developed by the authors. The questions were outlined after a review of the literature and circulated in an Internet-based survey format. Computed tomography (125, 92%) and chest X-ray (106, 78%) are the most common imaging modalities performed in the initial evaluation. Video-assisted thoracoscopic surgery for washout and pleurodesis (93, 68%) was reported as the preferred approach to patients with uncomplicated MPE. Sixty-one (45%) of the responding colleagues routinely use large bore chest tubes for draining malignant effusions. Forty-nine (35%) surgeons would not apply suction to the drainage system, whilst 50 (37%) would use -2 kPa or less. Talc (124, 91%) is the most commonly used sclerosing agent for pleurodesis in the context of malignant pleural effusion. The practice of 76 (56%) of the respondents is not informed by any clinical guidelines, whilst 60 (44%) reported adhering to the 2010 British Thoracic Society Pleural Disease Guideline. Seventy-one (52%) declared that the guidance was in need of updating or revision. This survey demonstrates the lacking adoption of the existing clinical guidance in this field, as well as the need for more contemporary guidelines for a better-informed practice. The ESTS Working Group on the management of MPE has been established for this purpose.

  6. An ISU study of asteroid mining

    Science.gov (United States)

    Burke, J. D.

    1991-01-01

    During the 1990 summer session of the International Space University, 59 graduate students from 16 countries carried out a design project on using the resources of near-earth asteroids. The results of the project, whose full report is now available from ISU, are summarized. The student team included people in these fields: architecture, business and management, engineering, life sciences, physical sciences, policy and law, resources and manufacturing, and satellite applications. They designed a project for transporting equipment and personnel to a near-earth asteroid, setting up a mining base there, and hauling products back for use in cislunar space. In addition, they outlined the needed precursor steps, beginning with expansion of present ground-based programs for finding and characterizing near-earth asteroids and continuing with automated flight missions to candidate bodies. (To limit the summer project's scope the actual design of these flight-mission precursors was excluded.) The main conclusions were that asteroid mining may provide an important complement to the future use of lunar resources, with the potential to provide large amounts of water and carbonaceous materials for use off earth. However, the recovery of such materials from presently known asteroids did not show an economic gain under the study assumptions; therefore, asteroid mining cannot yet be considered a prospective business.

  7. Formation of asteroid pairs by rotational fission.

    Science.gov (United States)

    Pravec, P; Vokrouhlický, D; Polishook, D; Scheeres, D J; Harris, A W; Galád, A; Vaduvescu, O; Pozo, F; Barr, A; Longa, P; Vachier, F; Colas, F; Pray, D P; Pollock, J; Reichart, D; Ivarsen, K; Haislip, J; Lacluyze, A; Kusnirák, P; Henych, T; Marchis, F; Macomber, B; Jacobson, S A; Krugly, Yu N; Sergeev, A V; Leroy, A

    2010-08-26

    Pairs of asteroids sharing similar heliocentric orbits, but not bound together, were found recently. Backward integrations of their orbits indicated that they separated gently with low relative velocities, but did not provide additional insight into their formation mechanism. A previously hypothesized rotational fission process may explain their formation-critical predictions are that the mass ratios are less than about 0.2 and, as the mass ratio approaches this upper limit, the spin period of the larger body becomes long. Here we report photometric observations of a sample of asteroid pairs, revealing that the primaries of pairs with mass ratios much less than 0.2 rotate rapidly, near their critical fission frequency. As the mass ratio approaches 0.2, the primary period grows long. This occurs as the total energy of the system approaches zero, requiring the asteroid pair to extract an increasing fraction of energy from the primary's spin in order to escape. We do not find asteroid pairs with mass ratios larger than 0.2. Rotationally fissioned systems beyond this limit have insufficient energy to disrupt. We conclude that asteroid pairs are formed by the rotational fission of a parent asteroid into a proto-binary system, which subsequently disrupts under its own internal system dynamics soon after formation.

  8. An Early Warning System for Asteroid Impact

    CERN Document Server

    Tonry, John L

    2010-01-01

    Earth is bombarded by meteors, occasionally by one large enough to cause a significant explosion and possible loss of life. Although the odds of a deadly asteroid strike in the next century are low, the most likely impact is by a relatively small asteroid, and we suggest that the best mitigation strategy in the near term is simply to move people out of the way. We describe an "early warning" system that could provide a week's notice of most sizable asteroids or comets on track to hit the Earth. This system, dubbed "Asteroid Terrestrial-impact Last Alert System" (ATLAS), comprises two observatories separated by about 100km that simultaneously scan the visible sky twice a night, and can be implemented immediately for relatively low cost. The sensitivity of ATLAS permits detection of 140m asteroids (100 Mton impact energy) three weeks before impact, and 50m asteroids a week before arrival. An ATLAS alarm, augmented by other observations, should result in a determination of impact location and time that is accura...

  9. Asteroid secular dynamics: Ceres' fingerprint identified

    CERN Document Server

    Novaković, Bojan; Tsirvoulis, Georgios; Knezević, Zoran

    2015-01-01

    Here we report on the significant role of a so far overlooked dynamical aspect, namely a secular resonance between the dwarf planet Ceres and other asteroids. We demonstrate that this type of secular resonance can be the dominant dynamical factor in certain regions of the main asteroid belt. Specifically, we performed a dynamical analysis of the asteroids belonging to the (1726) Hoffmeister family. To identify which dynamical mechanisms are actually at work in this part of the main asteroid belt, i.e. to isolate the main perturber(s), we study the evolution of this family in time. The study is accomplished using numerical integrations of test particles performed within different dynamical models. The obtained results reveal that the post-impact evolution of the Hoffmeister asteroid family is a direct consequence of the nodal secular resonance with Ceres. This leads us to the conclusion that similar effects must exist in other parts of the asteroid belt. In this respect, the obtained results shed light on an i...

  10. Asteroid Models from Multiple Data Sources

    CERN Document Server

    Durech, J; Delbo, M; Kaasalainen, M; Viikinkoski, M

    2015-01-01

    In the past decade, hundreds of asteroid shape models have been derived using the lightcurve inversion method. At the same time, a new framework of 3-D shape modeling based on the combined analysis of widely different data sources such as optical lightcurves, disk-resolved images, stellar occultation timings, mid-infrared thermal radiometry, optical interferometry, and radar delay-Doppler data, has been developed. This multi-data approach allows the determination of most of the physical and surface properties of asteroids in a single, coherent inversion, with spectacular results. We review the main results of asteroid lightcurve inversion and also recent advances in multi-data modeling. We show that models based on remote sensing data were confirmed by spacecraft encounters with asteroids, and we discuss how the multiplication of highly detailed 3-D models will help to refine our general knowledge of the asteroid population. The physical and surface properties of asteroids, i.e., their spin, 3-D shape, densit...

  11. A Survey of Channel Measurements and Models for Current and Future Railway Communication Systems

    Directory of Open Access Journals (Sweden)

    Paul Unterhuber

    2016-01-01

    Full Text Available Modern society demands cheap, more efficient, and safer public transport. These enhancements, especially an increase in efficiency and safety, are accompanied by huge amounts of data traffic that need to be handled by wireless communication systems. Hence, wireless communications inside and outside trains are key technologies to achieve these efficiency and safety goals for railway operators in a cost-efficient manner. This paper briefly describes nowadays used wireless technologies in the railway domain and points out possible directions for future wireless systems. Channel measurements and models for wireless propagation are surveyed and their suitability in railway environments is investigated. Identified gaps are pointed out and solutions to fill those gaps for wireless communication links in railway environments are proposed.

  12. Inference from the small scales of cosmic shear with current and future Dark Energy Survey data

    CERN Document Server

    MacCrann, N; Amara, A; Bridle, S L; Bruderer, C; Chang, C; Dodelson, S; Eifler, T F; Huff, E M; Huterer, D; Kacprzak, T; Refregier, A; Suchyta, E; Wechsler, R H; Zuntz, J; Abbott, T M C; Allam, S; Annis, J; Armstrong, R; Benoit-Lévy, A; Brooks, D; Burke, D L; Rosell, A Carnero; Kind, M Carrasco; Carretero, J; Castander, F J; Crocce, M; Cunha, C E; da Costa, L N; Desai, S; Diehl, H T; Dietrich, J P; Doel, P; Evrard, A E; Flaugher, B; Fosalba, P; Gerdes, D W; Goldstein, D A; Gruen, D; Gruendl, R A; Gutierrez, G; Honscheid, K; James, D J; Jarvis, M; Krause, E; Kuehn, K; Kuropatkin, N; Lima, M; Marshall, J L; Melchior, P; Menanteau, F; Miquel, R; Plazas, A A; Romer, A K; Rykoff, E S; Sanchez, E; Scarpine, V; Sevilla-Noarbe, I; Sheldon, E; Soares-Santos, M; Swanson, M E C; Tarle, G; Thomas, D; Vikram, V

    2016-01-01

    Cosmic shear is sensitive to fluctuations in the cosmological matter density field, including on small physical scales, where matter clustering is affected by baryonic physics in galaxies and galaxy clusters, such as star formation, supernovae feedback and AGN feedback. While muddying any cosmological information that is contained in small scale cosmic shear measurements, this does mean that cosmic shear has the potential to constrain baryonic physics and galaxy formation. We perform an analysis of the Dark Energy Survey (DES) Science Verification (SV) cosmic shear measurements, now extended to smaller scales, and using the Mead et al. 2015 halo model to account for baryonic feedback. While the SV data has limited statistical power, we demonstrate using a simulated likelihood analysis that the final DES data will have the statistical power to differentiate among baryonic feedback scenarios. We also explore some of the difficulties in interpreting the small scales in cosmic shear measurements, presenting estim...

  13. Physiotherapy management of patients undergoing thoracotomy procedure: A survey of current practice in Gauteng

    Directory of Open Access Journals (Sweden)

    Liezel Schwellnus

    2017-02-01

    Full Text Available Background: Physiotherapy is included in the management of patients undergoing thoracic surgery. The aim of this study was to describe physiotherapy practice in the management of patients who undergo an open thoracotomy.Methods: A cross-sectional study using convenience sampling was undertaken. An electronic self-administered questionnaire was distributed via SurveyMonkey to 1389 physiotherapists registered with the South African Society of Physiotherapy in Gauteng. The data collection period was August and September 2014 and data were analysed descriptively.Results: A total of 323 physiotherapists (23.3% responded to the survey and 141 (10.2% indicated that they treated patients with open thoracotomies. Preoperative treatment was done by 65 (41.6% and consisted of teaching supported coughing (92.3%; n = 60, sustained maximal inspiration (70.8%; n = 46 and the active cycle of breathing technique (69.2%; n = 45. One hundred and sixteen (82.3% respondents treated patients during their hospital stay. Deep breathing exercises (97.6%; n = 83, coughing (95.3%; n = 81, early mobilisation (95.3%; n = 81, upper limb mobility exercises (91.8%; n = 78, chest wall vibrations (88.2%; n = 75 and trunk mobility exercises (85.9%; n = 73 were done frequently. Pain management modalities were less common, for example transcutaneous electrical nerve stimulation (12.9%; n = 11. Post hospital physiotherapy management was uncommon (32.6%; n = 46.Conclusion: Physiotherapy related to early mobilisation in hospital is in line with evidence-based practice, but further education is needed regarding the need for physiotherapy post hospital discharge and pain management.

  14. Management of third stage labour following vaginal birth in Iran: a survey of current policies.

    Science.gov (United States)

    Afshari, Poorandokht; Medforth, Janet; Aarabi, Mohsen; Abedi, Parvin; Soltani, Hora

    2014-01-01

    this study was aimed to provide information on policies for the practice of managing the third stage of labour in Iran, including discussion of related systematic evidence. this survey used a standard questionnaire to obtain information about prevention and early treatment of postpartum haemorrhage from all geographical areas in Iran, in 2010. the survey included maternity units from 23 provinces, covering 129 out of a total of 560 maternity units in Iran. at least one public hospital, one private hospital and one rural birth facility unit were included from each province. Questionnaires were completed by the unit's senior midwife with support from the unit's lead obstetrician. all the units who were approached responded to the study including 69 public hospitals, 32 private hospitals and 28 rural birth facility units. The rate of active management of the third stage of labour was 57 per cent, although answers to individual components of management indicated a higher rate for active interventions than expectant management. Ninety-four per cent of the responding centres indicated oxytocin administration, 71 per cent apply early cord clamping and 65 per cent apply controlled cord traction. A lack of standard definition for postpartum haemorrhage was reported in 18 per cent of units. a high rate of active management was reported in Iran with variation in its different components which is in line with the international findings. These policies were mainly congruent with the existing systematic evidence except for timing of cord clamping. there is a need for improvement in locally sensitive policy development, continuing education, establishing accurate auditing systems and ensuring access to facilities such as blood banks and products in rural units. Efforts to reduce maternal mortality and morbidity and investigations into their causes should be extended to factors beyond the third stage of labour care clinical components. Crown Copyright © 2013. Published by

  15. Gynaecological cancer follow-up: national survey of current practice in the UK.

    Science.gov (United States)

    Leeson, Simon; Stuart, Nick; Sylvestre, Yvonne; Hall, Liz; Whitaker, Rhiannon

    2013-01-01

    To establish a baseline of national practice for follow-up after treatment for gynaecological cancer. Questionnaire survey. Gynaecological cancer centres and units. Members of the British Gynaecological Cancer Society and the National Forum of Gynaecological Oncology Nurses. A questionnaire survey. To determine schedules of follow-up, who provides it and what routine testing is used for patients who have had previous gynaecological cancer. A total of 117 responses were obtained; 115 (98%) reported hospital scheduled regular follow-up appointments. Two involved general practitioners. Follow-up was augmented or replaced by telephone follow-up in 29 responses (25%) and patient-initiated appointments in 38 responses (32%). A total of 80 (68%) cancer specialists also offered combined follow-up clinics with other specialties. Clinical examinations for hospital-based follow-up were mainly performed by doctors (67% for scheduled regular appointments and 63% for patient-initiated appointments) while telephone follow-up was provided in the majority by nurses (76%). Most respondents (76/117 (65%)) provided routine tests, of which 66/76 (87%) reported carrying out surveillance tests for ovarian cancer, 35/76 (46%) for cervical cancer, 8/76 (11%) for vulval cancer and 7/76 (9%) for endometrial cancer. Patients were usually discharged after 5 years (82/117 (70%)), whereas three (3%) were discharged after 4 years, nine (8%) after three years and one (1%) after 2 years. Practice varied but most used a standard hospital-based protocol of appointments for 5 years and routine tests were performed usually for women with ovarian cancer. A minority utilised nurse-led or telephone follow-up. General practitioners were rarely involved in routine care. A randomised study comparing various models of follow-up could be considered.

  16. Household food security in Isfahan based on current population survey adapted questionnaire

    Directory of Open Access Journals (Sweden)

    Morteza Rafiei

    2013-01-01

    Full Text Available Background: Food security is a state in which all people at every time have physical and economic access to adequate food to obviate nutritional needs and live a healthy and active life. Therefore, this study was performed to quantitatively evaluate the household food security in Esfahan using the localized version of US Household Food Security Survey Module (US HFSSM. Methods: This descriptive cross-sectional study was performed in year 2006 on 3000 households of Esfahan. The study instrument used in this work is 18-item US food security module, which is developed into a localized 15-item questionnaire. This study is performed in two stages of families with no children (under 18 years old and families with children over 18 years old. Results: The results showed that item severity coefficient, ratio of responses given by households and item infit and outfit coefficient in adult′s and children′s questionnaire respectively. According to obtained data, scale score of +3 in adults group is described as determination limit of slight food insecurity and +6 is stated as the limit for severe food insecurity. For children′s group, scale score of +2 is defined to be the limit of slight food insecurity and +5 is the determination limit of severe food insecurity. Conclusions: The main hypothesis of this survey analysis is based on the raw scale score of USFSSM The item of "lack of enough money for buying food" (item 2 and the item of "lack of balanced meal" (3 rd item have the lowest severity coefficient. Then, the ascending rate of item severity continues in first item, 4 th item and keeps increasing into 10 th item.

  17. On the rotation rates and axis ratios of the smallest known near-Earth asteroids---the archetypes of the Asteroid Redirect Mission targets

    CERN Document Server

    Hatch, Patrick

    2015-01-01

    NASA's Asteroid Redirect Mission (ARM) has been proposed with the aim to capture a small asteroid a few meters in size and redirect it into an orbit around the Moon. There it can be investigated at leisure by astronauts aboard an Orion or other spacecraft. The target for the mission has not yet been selected, and there are very few potential targets currently known. Though sufficiently small near-Earth asteroids (NEAs) are thought to be numerous, they are also difficult to detect and characterize with current observational facilities. Here we collect the most up-to-date information on the smallest known near-Earth asteroids to outline the properties of these small NEAs as currently understood, in order to examine what the eventual ARM target might be like. Observational biases certainly mean that our sample is not an ideal representation of the true population of small NEAs. However our sample is representative of the eventual target list for the ARM mission, which will be compiled under very similar observa...

  18. Catheter-Based Educational Experiences: A Canadian Survey of Current Residents and Recent Graduates in Cardiac Surgery.

    Science.gov (United States)

    Juanda, Nadzir; Chan, Vincent; Chan, Ryan; Rubens, Fraser D

    2016-03-01

    The past decade has witnessed significant developments in the use of catheter-based therapies in cardiovascular medicine. We sought to assess the educational opportunities for cardiac surgery trainees to determine their readiness for participation in these strategies. A web-based survey was distributed to current residents, recent graduates, and program directors in Canadian cardiac surgery residency programs from 2008-2013. The survey was distributed to 110 residents and graduates. Forty-five percent completed the survey. Thirty-five percent expressed that they experienced resistance organizing their rotations because they had to compete with non-cardiac surgery colleagues, and 6 were denied local cardiac catheterization rotations. By the end of the rotation, 56% were comfortable performing a diagnostic cardiac catheterization independently. Exposure to being the operator performing diagnostic catheterization was significantly associated with the positive perception of being able to perform a diagnostic catheterization independently (odds ratio [OR], 5.14; 95% confidence interval [CI], 1.33-19.81; P = 0.017). Eighty-eight percent of respondents expressed the need for more exposure in catheter-based rotations. Seven of 11 program directors completed the survey. All believed such rotations should be mandatory and foresaw a bigger role for hybrid catheter-based/cardiac surgery procedures in the future. Trainees and program directors perceive that increased exposure to catheter-based therapies is important to career development as a cardiac surgeon. This survey will contribute to the development of a cardiac surgery training curriculum as we foresee more hybrid and team procedures.

  19. Clinical skills training in obstetrics - a descriptive survey of current practice in Denmark

    DEFF Research Database (Denmark)

    Nielsen, Mathilde Maagaard; Johansen, Marianne; Lottrup, Pernille

    2012-01-01

    The Danish National Board of Health has recommended that labor wards establish regular obstetric emergency skills training programs. The aim of this study was to describe current practice in Denmark. A questionnaire was sent to all obstetric departments in Denmark in 2008. All responded. Simulation......-based training was conducted in 26/28 obstetrical departments. Settings for the training programs were mainly local. Training was provided for shoulder dystocia, postpartum bleeding and basic neonatal resuscitation in almost all the departments, but was not organized in a uniform way. Neither the program itself...... nor the participants' performance was evaluated in a structured or validated way. Obstetric emergency skills training is being actively conducted in the majority of the Danish labor wards. However, it still remains a challenge to ensure the uniform organization and evaluation of the current training...

  20. Current Status of Huntington’s Disease in Korea: A Nationwide Survey and National Registry Analysis

    OpenAIRE

    Kim, Hyun Sook; Lyoo, Chul Hyoung; Lee, Phil Hyu; Kim, Sang Jin; Park, Mee Young; Ma, Hyeo-Il; Lee, Jae Hyeok; Song, Sook Kun; Baik, Jong Sam; Kim, Jin Ho; Lee, Myung Sik

    2015-01-01

    Objective Huntington’s disease (HD) is a rare neurological disorder, and its current status in Korea is not well investigated. This study aims to determine the prevalence and incidence of HD and to investigate the clinical features of HD patients in Korea. Methods We estimated the crude prevalence and annual incidence of HD based on the databases of the Rare Diseases Registry (RDR) and the National Health Insurance (NHI). The clinical data of genetically confirmed HD patients was collected fr...

  1. Survey on Current Conditions and Intention of Outbound Investment by Chinese Enterprises (Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    China Council for the Promotion of International T

    2010-01-01

    @@ Situation of the Overseas Investments of Chinese Enterprises 1. Small scale of investments Of the respondent enterprise having made overseas in-vestments, those with an investment amount of less than one million USD account for 61%, and only ten of them made investments exceeding 100 million USD, accounting for only about 1%. It thus appears that the overall scale of current overseas investments of Chinese enterprises is small, and only a very few enterprises have made large scale overseas invest-ments.

  2. A national survey of Rett syndrome: age, clinical characteristics, current abilities, and health.

    Science.gov (United States)

    Cianfaglione, Rina; Clarke, Angus; Kerr, Mike; Hastings, Richard P; Oliver, Chris; Felce, David

    2015-07-01

    As part of a wider study to investigate the behavioral phenotype of a national sample of girls and women with Rett syndrome (RTT) in comparison to a well-chosen contrast group and its relationship to parental well-being, the development, clinical severity, current abilities and health of 91 participants were analyzed in relation to diagnostic, clinical and genetic mutation categories. Early truncating mutations or large deletions were associated with greater severity. Early regression was also associated with greater severity. All three were associated with lower current abilities. Epilepsy and weight, gastrointestinal and bowel problems were common co-morbidities. Participants with classic RTT had greater health problems than those with atypical RTT. A substantial minority of respondents reported fairly frequent signs of possible pain experienced by their relative with RTT. Overall, the study provides new data on the current abilities and general health of people with RTT and adds to the evidence that the severity of the condition and variation of subsequent disability, albeit generally within the profound range, may be related to gene mutation. The presence of certain co-morbidities represents a substantial ongoing need for better health. The experience of pain requires further investigation.

  3. Current situation of depression healthcare in Spain: results of a psychiatrists' survey

    Directory of Open Access Journals (Sweden)

    Belén Martín-Águeda

    2006-12-01

    Full Text Available Objective: To analyze the current situation of healthcare for depression in Spain, according to psychiatrists opinion, and how it has evolved over the last 20 years, comparativily with the results reported in previous studies of our group. Methods: Throughout 2002, we recorded the opinions of 101 specialists in psychiatry after asking them to fill out structured questionnaires in which they rated care, clinical, therapeutic and care quality. Results: The presence of depressive disorders in healthcare is substantial, despite the high figures for "concealed epidemiology", with an increase in these last 20 years of disorders comorbid with anxiety. Currently, most patients arrive at the psychiatrist having been referred by their general practitioners (GP, as there is now less reluctance in depressive patients to such referral. In the last years there has been an increase in pharmacological treatment, with adverse effects of the drugs representing the major obstacle to non-adherence to such treatment. Selective serotonin reuptake inhibitors (SSRIs constitute the pharmacological group of choice, and are the drugs most commonly used in the treatment of depression, together with venlafaxine. Areas where there is a need for improvement are time devoted to consultation, coordination between GPs and psychiatrists, waiting lists, and resources available to Mental Health Units. Conclusions: Current situation of depression healthcare in Spain has substantially changed in recent years, improving in some aspects, thanks, in part, to the attitudes of GPs with this disorder and to evolution of pharmacological treatment.

  4. Spectral properties of near-Earth and Mars-crossing asteroids using Sloan photometry

    Science.gov (United States)

    Carry, B.; Solano, E.; Eggl, S.; DeMeo, F. E.

    2016-04-01

    The nature and origin of the asteroids orbiting in near-Earth space, including those on a potentially hazardous trajectory, is of both scientific interest and practical importance. We aim here at determining the taxonomy of a large sample of near-Earth and Mars-crosser asteroids and analyze the distribution of these classes with orbit. We use this distribution to identify the source regions of near-Earth objects and to study the strength of planetary encounters to refresh asteroid surfaces. We measure the photometry of these asteroids over four filters at visible wavelengths on images taken by the Sloan Digital Sky Survey (SDSS). These colors are used to classify the asteroids into a taxonomy consistent with the widely used Bus-DeMeo taxonomy (DeMeo et al. [2009]. Icarus 202, 160-180) based on visible and near-infrared spectroscopy. We report here on the taxonomic classification of 206 near-Earth and 776 Mars-crosser asteroids determined from SDSS photometry, representing an increase of 40% and 663% of known taxonomy classifications in these populations. Using the source region mapper by Greenstreet et al. (Greenstreet, S., Ngo, H., Gladman, B. [2012]. Icarus, 217, 355-366), we compare for the first time the taxonomic distribution among near-Earth and main-belt asteroids of similar diameters. Both distributions agree at the few percent level for the inner part of the main belt and we confirm this region as a main source of near-Earth objects. The effect of planetary encounters on asteroid surfaces are also studied by developing a simple model of forces acting on a surface grain during planetary encounter, which provides the minimum distance at which a close approach should occur to trigger resurfacing events. By integrating numerically the orbit of the 519 S-type and 46 Q-type asteroids in our sample back in time for 500,000 years and monitoring their encounter distance with Venus, Earth, Mars, and Jupiter, we seek to understand the conditions for resurfacing

  5. Gemini and Keck Observations of Slowly Rotating, Bilobate Active Asteroid (300163)

    Science.gov (United States)

    Waniak, Waclaw; Drahus, Michal

    2016-10-01

    One of the most puzzling questions regarding Active Asteroids is the mechanism of their activation. While some Active Asteroids show protracted and often recurrent mass loss, consistent with seasonal ice sublimation, some other eject dust impulsively as a result of a catastrophic disruption (e.g. Jewitt et al. 2015, Asteroids IV, 221). It has been suggested that ice can be excavated from the cold near-surface interior by an impact (Hsieh & Jewitt 2006, Science 312, 561) or, for small objects susceptible to YORP torques, by near-critical spin rate (Sheppard & Trujillo 2014, AJ 149, 44). But impact and rapid spin can also cause a catastrophic disruption (e.g. Jewitt et al. 2015, Asteroids IV, 221). It therefore becomes apparent that the different types of mass loss observed in Active Asteroids can be best classified and understood based on the nucleus spin rates (Drahus et al. 2015, ApJL 802, L8), but unfortunately the rotation periods have been measured for a very limited number of these objects. With this in mind we have initiated a survey of light curves of small Active Asteroids on the largest ground-based optical telescopes. Here we present the results for (300163), also known as 288P and 2006 VW139, which is a small 2.6-km sized asteroid that exhibited a comet-like activity over 100 days in the second half of 2011 (Hsieh et al. 2012, ApJL 748, L15; Licandro et al. 2013, A&A 550, A17; Agarwal et al. 2016, AJ 151, 12). Using Keck/DEIMOS and Gemini/GMOS-S working in tandem on UT 2015 May 21-22 we have detected an inactive nucleus and measured a complete, dense, high-S/N rotational light curve. The light curve has a double-peaked period of 16 hours, an amplitude of 0.4 mag, and moderately narrow minima suggesting a bilobate or contact-binary shape. The long rotation period clearly demonstrates a non-rotational origin of activity of this object, consistent with an impact. Furthermore, among the five small Active Asteroids with known rotation periods (300163) is only

  6. Lightcurves for Two Near-Earth Asteroids by Asteroids Observers (OBAS) - MPPD: 2016 April-May

    Science.gov (United States)

    Martinez, Vicente Mas; Silva, Gonzalo Fornas; Martinez, Angel Flores; Garceran, Alfonso Carreno; Mansego, Enrique Arce; Rodriguez, Pedro Brines; de Haro, Juan Lozano; Silva, Alvaro Fornas; Chiner, Onofre Rodrigo; Porta, David Herrero

    2016-10-01

    We report on the results of photometric analysis of two near-Earth asteroids (NEA) by Asteroids Observers (OBAS). This work is part of the Minor Planet Photometric Database (MPPD) project initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  7. Sixteen Asteroids Lightcurves at Asteroids Observers (OBAS) - MPPD: 2016 June-November

    Science.gov (United States)

    Brines, Pedro; Lozano, Juan; Rodrigo, Onofre; Fornas, A.; Herrero, David; Mas, Vicente; Fornas, G.; Carreño, A.; Arce, Enrique

    2017-04-01

    We report on the photometric analysis result of sixteen main-belt asteroids (MBA) done by Asteroids Observers (OBAS). This work is part of the Minor Planet Photometric Database tasks, initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  8. Eighteen Asteroids Lightcurves at Asteroides Observers (OBAS) - MPPD: 2016 March-May

    Science.gov (United States)

    Mansego, Enrique Arce; Rodriguez, Pedro Brines; de Haro, Juan Lozano; Chiner, Onofre Rodrigo; Silva, Alvaro Fornas; Porta, David Herrero; Martinez, Vicente Mas; Silva, Gonzalo Fornas; Garceran, Alfonso Carreno

    2016-10-01

    We report on the analysis of photometric observations of 18 main-belt asteroids (MBA) done by Asteroides Observers (OBAS). This work is part of the Minor Planet Photometric Database program initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  9. Twenty-three Asteroids Lightcurves at Observadores de Asteroides (OBAS): 2015 October - December

    Science.gov (United States)

    Aznar Macias, Amadeo; Carreno Garcerain, Alfonso; Arce Mansego, Enrique; Brines Rodriguez, Pedro; Lozano de Haro, Juan; Fornas Silva, Alvaro; Fornas Silva, Gonzalo; Mas Martinez, Vicente; Rodrigo Chiner, Onofre

    2016-04-01

    We report on the photometric analysis results for 23 main-belt asteroids (MBA) done by Observadores de Asteroides (OBAS). This work is part of the Minor Planet Photometric Database that was initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate, complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  10. Physical Characterization of the Binary Asteroid 66146 (1998 Tu3)

    Science.gov (United States)

    Truong, Thien-Tin; Hicks, M.; Mayes, D.; Barajas, T.; Garcia, K.

    2011-01-01

    The near-Earth asteroid 66146 (1998 TU3) was discovered on 1998 October 13 by the LINEAR NEO survey (MPEC 1998-U03). We obtained five nights of Bessel BVRI observations (2010 Aug 6,7,10,12,13 UT) and one night of Bessel R (August 8 PST) at the JPL Table Mountain Observatory (TMO) 0.6-m telescope near Wrightwood, California. These observations were obtained as part of our ongoing survey at TMO of Potentially Hazardous Asteroids (PHAs), planetary radar targets, and low delta-V near-Earth asteroids (NEOs). The object's rotationally averaged colors (B-R=1.238+/-0.011 mag; V-R=0.440+/-0.008 mag; R-I=0.275+/-0.010 mag) were found most compatible with an Sk-type spectral classification (Bus Taxonomy)/S-type (Tholen Taxonomy). This association was obtained through a comparison of our colors with the 1341 asteroid spectra in the SMASS II database (Bus & Binzel 2002). Our classification differs significantly from the Q-type taxonomy reported by Whitely (2002). Assuming a solar phase parameter g=0.15 we performed a period search using standard Fourier techniques. We found a best-fit rotational period Psyn=2.378+/-0.001 hr, in excellent agreement with the 2.3779+/-0.0004 period determined by Richards et al. (2007). The dispersion in the phased single period lightcurve strongly suggests that 1998 TU3 is be a binary system, with variations in observed flux caused by an unresolved, tidally locked secondary companion. Fitting a 2-period model as described by Pravec et al. (2000), we found that our photometry agrees well with a binary model (P1=2.378+/-0.01 hr, P2=28.28+/-0.05 hr). We have three additional nights scheduled for this object at TMO (Oct 8, 9, 10 2010 UT), extending our solar phase coverage and allowing us to refine our rotational models. 1998 TU3 will experience an exceptional apparition in 2012. This object may be a good candidate for shape/pole modeling via lightcurve inversion, especially if photometry can be obtained from both northern and southern hemispheres. We

  11. Near Earth Asteroids- Prospection, Orbit Modification and Mining

    Science.gov (United States)

    Grandl, W.; Bazso, A.

    2014-04-01

    thrust and specific impulse to move the huge masses of the asteroids. Such a propulsion system could be the Bussard Fusion System, also known as the quiet-electricdischarge (QED) engine. It uses electrostatic fusion devices to generate electrical power. The fuel consists of Deuterium and Helium3 that are fusing to Helium4 plus protons releasing 18.3 MeV of energy per reaction. The charged protons escape from the confinement; their kinetic energy can be converted to electricity or be used directly as a plasma beam for generating thrust. For the reaction a specific energy of 3.5x1014 Joule/kg can be computed, i.e. orders-ofmagnitude higher than for any existing propulsion system. As an example we take the Asteroid with the designation 2008 EV5. It is classified as an Aten group asteroid with a mean diameter of 450 meters and belongs to spectral type S (stony asteroids). Our mass estimate (using a bulk density of 3 g/cm^3) is 1.4x1011 kg. To transfer 2008 EV5 to an Earth-like orbit the energy required is estimated to be in the order of 2.8x1018 Joule. This is the difference in Kepler energy between the NEA's current orbit and the Earth's orbit around the sun. Using the Bussard Fusion System the amount of fuel would be approx. 8000 kg of Helium3. To move an asteroid by remote control the authors propose to design unmanned space tugs which are propelled by Bussard Fusion Engines. A pair of space tugs is docked to each asteroid using drilling anchors. The fusion engines of the tugs then apply the thrust forces for the maneuvers. The first tug, which carries the main fuel quantity, applies the primary force for the orbital maneuvers. The second one adjust the flight track by short engine thrusts.

  12. The Relationship between the Boltysh and Chicxulub Asteroid Impacts: Implications for Celestial Mechanics at the K/Pg boundary

    Science.gov (United States)

    Kelley, S. P.; Jolley, D.; Gurov, E.; Gilmour, I.; Watson, J.

    2009-12-01

    One of the most popular explanations for the mass extinction of life at the end of the Cretaceous period 65 million years ago has been a single asteroid impact at Chicxulub on the Yucatan peninsula, Mexico. The discovery of a second smaller crater at Boltysh in the Ukraine with a similar age raised the possibility that a shower of asteroids or comets impacted Earth close to the K/Pg boundary. Similar terrestrial impact clusters have been detected 35, 370 and 470 Ma. New palynological, sedimentary and del13C evidence from the lowest 5 m of a new core of crater fill sediments in the Boltysh impact crater. Our analyses demonstrate that a post-impact flora formed on the ejecta layer of the Boltysh crater, was in turn devastated by the K/Pg events just a few hundred to a few thousand years later. We conclude that the Boltysh crater pre-dated Chicxulub by less than 2,000 years, a timescale that constrains the likely origin of the bodies that formed the two known craters. Sudden expulsions of asteroids from resonance bands in the asteroid belt shower Earth over many millions of years, but asteroids ejected from the J5:2 resonance band reach Earth within 50,000 to 1 million years, making it likely that two or more large craters would form within a few hundred to a few thousand years. This result implies that the K/Pg boundary events included at least two large asteroid impacts and that showers of asteroids are perhaps more prominent features of the long term terrestrial impact record than background random impacts. If asteroid showers also dominate the recent impact record, tracking and mapping the currently known asteroid families is likely to reduce the long term NEO hazard.

  13. International CJMT-1 Workshop on Asteroidal Science

    Science.gov (United States)

    Ip, Wing-Huen

    2014-03-01

    An international workshop on asteroidal science was held between October 16 and 17, 2012, at the Macau University of Science and Technology gathering together experts on asteroidal study in China, Japan, Macao and Taiwan. For this reason, we have called it CJMT-1 Workshop. Though small in sizes, the asteroids orbiting mainly between the orbit of Mars and of Jupiter have important influence on the evolution of the planetary bodies. Topics ranging from killer asteroids to space resources are frequently mentioned in news reports with prominence similar to the search for water on Mars. This also means that the study of asteroids is very useful in exciting the imagination and interest in science of the general public. Several Asian countries have therefore developed long-term programs integrating ground-based observations and space exploration with Japan being the most advanced and ambitious as demonstrated by the very successful Hayabusa mission to asteroid 25143 Itokawa. In this volume we will find descriptions of the mission planning of Hayabusa II to the C-type near-Earth asteroid, 1999 JU3. Not to be outdone, China's Chang-E 2 spacecraft was re-routed to a flyby encounter with asteroid 4179 Toutatis in December 2012. It is planned that in the next CJMT workshop, we will have the opportunity to learn more about the in-depth data analysis of the Toutatis observations and the progress reports on the Hayabusa II mission which launch date is set to be July 2014. Last but not least, the presentations on the ground-based facilities as described in this volume will pave the way for coordinated observations of asteroidal families and Trojan asteroids - across Asia from Taiwan to Uzbekistan. Such international projects will serve as an important symbol of good will and peaceful cooperation among the key members of this group. Finally, I want to thank the Space Science Institute, Macao University of Science and Technology, for generous support, and its staff members

  14. Yarkovsky V-shape identification of asteroid families

    Science.gov (United States)

    Bolin, Bryce T.; Delbo, Marco; Morbidelli, Alessandro; Walsh, Kevin J.

    2017-01-01

    There are only a few known main belt (MB) asteroid families with ages greater than 2 Gyr (Brož et al., 2013; Spoto et al., 2015). Estimates based on the family producing collision rate suggest that the lack of > 2 Gyr-old families may be due to a selection bias in current techniques used to identify families. Family fragments disperse in their orbital elements, semi-major axis, a, eccentricity, e, and inclination, i, due to secular resonances, close encounters with massive asteroids and the non-gravitational Yarkovsky force. This causes the family fragments to be indistinguishable from the background of the main belt making them more difficult to identify with the hierarchical clustering method (HCM) with increasing family age. The discovery of the Eulalia and new Polana families in the inner belt relied on new techniques because Yarkovsky spreading made them too disperse to be identified using the classical HCM. The techniques used to discover the new Polana and Eulalia families are modified here to identify asteroid families by searching for correlations between a and asteroid diameter, D, or absolute magnitude, H. A group of asteroids is identified as a collisional family if its boundary in the a vs. 1/D or a vs. H planes has a characteristic V-shape which is due to the size dependent Yarkovsky spreading. The V-shape boundary is identified with two separate techniques. The first technique identifies a border by measuring a steep drop between the number of objects inside and outside of the border. The second technique identifies the V-shape border by measuring a peak in the number density of objects in a vs. 1/D , H space. Families are identified with just one or both V-shape identifying techniques. The V-shape techniques are demonstrated on the known families of Erigone, Vesta, Koronis, and families difficult to identify by HCM such as Flora, Baptistina, new Polana, Eulalia and Karin. Future applications of the technique, such as in a large scale search for > 2

  15. Imaging and image management: A survey on current outlook and awareness in pathology practice

    Directory of Open Access Journals (Sweden)

    M Indu

    2015-01-01

    Full Text Available Background: Flexibility of digital photography enables it to be an integral part of pathology practice. An assessment of guidelines of imaging is essential for proper usage of photographs. Objectives: The purpose of the study was to assess awareness of oral pathologists about various aspects of medical photography. Methods: Questionnaire based on the availability of facilities, usage, technical details and ethical issues of medical photography was sent to postgraduate students and teaching faculties of Oral Pathology in various localities in India. Results: Photographs were taken mostly for the purposes of publication, medical documentation and education. Significant number of postgraduate students and faculties of Oral Pathology didn′t receive any training or hadn′t gone through any publications/books (P = 0.000 about medical photography. Consent for patient photography was taken by significant number of respondents (P = 0.000 but in a verbal form. Majority of people used image editing software, but 19.0% of faculties and 21.1% of postgraduate students were unaware of deleterious effect of image editing. Firm and sensible instructions concerning image storage, sharing and accessibility were not yet created. Conclusion: This survey drew attention towards lack of proper understanding about the technical details, medical protocols and ethical issues related to medical photography. These findings recommend implementation of basic training for medical photography and policy for image management for students and faculties in every health care institution.

  16. Current practice of antithrombotic treatment in ischemic stroke: a survey among Hungarian neurologists.

    Science.gov (United States)

    Sztriha, Lśzló K; Vécsei, László

    2008-05-30

    Large multicenter trials have already evaluated the relative benefit of various types of antithrombotic medication in ischemic stroke. However, the application of the trial results still remains uncertain in some clinical situations. We set out to evaluate the various aspects of antithrombotic treatment use among clinical practitioners. A virtually nationwide survey was performed among Hungarian neurologists involved in stroke care, who responded to a questionnaire concerning the use of antiplatelet agents and anticoagulation in acute ischemic stroke and for secondary prevention. The response rate was 65%. Most (69%) practitioners always wait for brain imaging before initiating antithrombotic treatment in acute stroke. Aspirin (100 mg/day) is the most frequently prescribed antiplatelet agent after a first ischemic episode. Common reasons for the prescription of alternative agents instead of aspirin after a first attack include high-risk cases and intolerance or allergy to aspirin. The results of in vitro platelet aggregation studies frequently influence drug selection. If an event recurs during a given antiplatelet treatment, most neurologists change the medication. Some participants reported the administration of anticoagulation, or of the combination of aspirin plus clopidogrel in certain situations that are not cardiological indications. This study provides information on the use of antithrombotic treatment in general neurological practice, including everyday clinical situations where no help is available from guidelines.

  17. Current status of rodenticide intoxication in Brazil: a preliminary survey from 2009 to 2011

    Directory of Open Access Journals (Sweden)

    Solange Papini

    2014-10-01

    Full Text Available The chemical control of rodents with anticoagulant products, especially derivatives of the coumarin chemical group, is legally authorised in Brazil. These products provide effective control and are safe for humans. However, the use of illegal 'rodenticides' has increased in many Brazilian cities recently, accompanied by increased numbers of suicides, homicides, and intoxications. The National Toxicology Information System (Sinitox registers the number of rodenticide intoxications, including suicides, but does not differentiate between the legal and illegal rodenticides. Intoxications by rodenticides outnumber those by illicit drugs and pesticides. A survey of data from 2005-2011 revealed an average of about 3,800 intoxications per year, about 60% of which were suicides. Many of these intoxications probably involved illegal rodenticides, some with unknown chemical compositions, which confound the data on rodenticide intoxication. This evaluation of Sinitox data highlighted the need to ensure the proper use of the term 'rodenticide' when registering intoxication cases. Intoxication by-products that are not rodenticides, but are erroneously used for this purpose, should be classified separately to improve the quality of information.

  18. Inference from the small scales of cosmic shear with current and future Dark Energy Survey data

    Energy Technology Data Exchange (ETDEWEB)

    MacCrann, N.; Aleksić, J.; Amara, A.; Bridle, S. L.; Bruderer, C.; Chang, C.; Dodelson, S.; Eifler, T. F.; Huff, E. M.; Huterer, D.; Kacprzak, T.; Refregier, A.; Suchyta, E.; Wechsler, R. H.; Zuntz, J.; Abbott, T. M. C.; Allam, S.; Annis, J.; Armstrong, R.; Benoit-Lévy, A.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; Crocce, M.; Cunha, C. E.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Flaugher, B.; Fosalba, P.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Jarvis, M.; Krause, E.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Marshall, J. L.; Melchior, P.; Menanteau, F.; Miquel, R.; Plazas, A. A.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Sheldon, E.; Soares-Santos, M.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.

    2016-11-05

    Cosmic shear is sensitive to fluctuations in the cosmological matter density field, including on small physical scales, where matter clustering is affected by baryonic physics in galaxies and galaxy clusters, such as star formation, supernovae feedback and AGN feedback. While muddying any cosmological information that is contained in small scale cosmic shear measurements, this does mean that cosmic shear has the potential to constrain baryonic physics and galaxy formation. We perform an analysis of the Dark Energy Survey (DES) Science Verification (SV) cosmic shear measurements, now extended to smaller scales, and using the Mead et al. 2015 halo model to account for baryonic feedback. While the SV data has limited statistical power, we demonstrate using a simulated likelihood analysis that the final DES data will have the statistical power to differentiate among baryonic feedback scenarios. We also explore some of the difficulties in interpreting the small scales in cosmic shear measurements, presenting estimates of the size of several other systematic effects that make inference from small scales difficult, including uncertainty in the modelling of intrinsic alignment on nonlinear scales, `lensing bias', and shape measurement selection effects. For the latter two, we make use of novel image simulations. While future cosmic shear datasets have the statistical power to constrain baryonic feedback scenarios, there are several systematic effects that require improved treatments, in order to make robust conclusions about baryonic feedback.

  19. Current practice in regional anaesthesia in South America: An online survey.

    Science.gov (United States)

    Corvetto, M A; Carmona, J; Vásquez, M I; Salgueiro, C; Crostón, J; Sosa, R; Folle, V; Altermatt, F R

    2017-01-01

    A survey was conducted in order to obtain a profile of the practice of regional anesthesia in South America, and determine the limitations of its use. After institutional ethics committee approval, a link to an online questionnaire was sent by e-mail to anaesthesiologists in Argentina, Bolivia, Chile, Colombia, Panamá, Paraguay, Perú, and Uruguay. The questionnaire was processed anonymously. A total of 1,260 completed questionnaires were received. The results showed that 97.6% of the anaesthesiologists that responded used regional anaesthesia in clinical practice, 66.9% performed peripheral nerve block (PNB) regularly, 21.6% used continuous PNB techniques, and 4.6% used stimulating catheters. The primary source of training was residency programs. As regards PNB, the most common performed were interscalene (52.3%), axillary (45.1%), femoral (43.2%), and ankle block (43%). As regards the localisation technique employed, 16% used paraesthesia, 44.2% used a peripheral nerve stimulator, and 18.1% ultrasound guidance. Regional anaesthesia and PNB are commonly used among South American anaesthesiologists. Considering that each country has its own profile for use, this profile should guide training in clinical practice, especially in residency programs. Copyright © 2016 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  20. Inference from the small scales of cosmic shear with current and future Dark Energy Survey data

    Science.gov (United States)

    MacCrann, N.; Aleksić, J.; Amara, A.; Bridle, S. L.; Bruderer, C.; Chang, C.; Dodelson, S.; Eifler, T. F.; Huff, E. M.; Huterer, D.; Kacprzak, T.; Refregier, A.; Suchyta, E.; Wechsler, R. H.; Zuntz, J.; Abbott, T. M. C.; Allam, S.; Annis, J.; Armstrong, R.; Benoit-Lévy, A.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; Crocce, M.; Cunha, C. E.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Flaugher, B.; Fosalba, P.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Jarvis, M.; Krause, E.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Marshall, J. L.; Melchior, P.; Menanteau, F.; Miquel, R.; Plazas, A. A.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Sheldon, E.; Soares-Santos, M.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; DES Collaboration

    2017-03-01

    Cosmic shear is sensitive to fluctuations in the cosmological matter density field, including on small physical scales, where matter clustering is affected by baryonic physics in galaxies and galaxy clusters, such as star formation, supernovae feedback, and active galactic nuclei feedback. While muddying any cosmological information that is contained in small-scale cosmic shear measurements, this does mean that cosmic shear has the potential to constrain baryonic physics and galaxy formation. We perform an analysis of the Dark Energy Survey (DES) Science Verification (SV) cosmic shear measurements, now extended to smaller scales, and using the Mead et al. (2015) halo model to account for baryonic feedback. While the SV data has limited statistical power, we demonstrate using a simulated likelihood analysis that the final DES data will have the statistical power to differentiate among baryonic feedback scenarios. We also explore some of the difficulties in interpreting the small scales in cosmic shear measurements, presenting estimates of the size of several other systematic effects that make inference from small scales difficult, including uncertainty in the modelling of intrinsic alignment on non-linear scales, 'lensing bias', and shape measurement selection effects. For the latter two, we make use of novel image simulations. While future cosmic shear data sets have the statistical power to constrain baryonic feedback scenarios, there are several systematic effects that require improved treatments, in order to make robust conclusions about baryonic feedback.

  1. Current Dermatologic Care in Dutch Nursing Homes and Possible Improvements: A Nationwide Survey.

    Science.gov (United States)

    Lubeek, Satish F K; van der Geer, Eric R; van Gelder, Marleen M H J; Koopmans, Raymond T C M; van de Kerkhof, Peter C M; Gerritsen, Marie-Jeanne P

    2015-08-01

    To assess the provision and need of dermatologic care among Dutch nursing home patients and to obtain recommendations for improvement. Cross-sectional nationwide survey. All 173 nursing home organizations in the Netherlands. Physicians working in nursing homes. Web-based questionnaire concerning the burden of skin diseases in nursing home patients, diagnostic procedures and therapy, collaboration with dermatologists, physicians' level of education, and suggestions for improvement. A total of 126 (72.8%) nursing home organizations, with 1133 associated physicians participated in our study and received the questionnaire. A total of 347 physicians (30.6%) completed the questionnaire. Almost all respondents (99.4%) were recently confronted with skin diseases, mostly (pressure) ulcers, eczema, and fungal infections. Diagnostic and treatment options were limited because of a lack of availability and experience of the physicians. More live consultation of dermatologists was suggested as being important to improve dermatologic care. Other suggestions were better education, more usage of telemedicine applications, and better availability of diagnostic and/or treatment procedures like cryotherapy. Physicians in nursing homes are frequently confronted with skin diseases. Several changes in organization of care and education are expected to improve dermatologic care in nursing home patients. Copyright © 2015 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

  2. Life-threatening complications after ureteroscopy for urinary stones: survey and revision of the current literature.

    Science.gov (United States)

    Cindolo, Luca; Castellan, Pietro; Primiceri, Giulia; Hoznek, Andras; Cracco, Cecilia M; Scoffone, Cesare M; Galfano, Antonio; Petralia, Giovanni; DE Angelis, Michele; Annino, Filippo; Malacasa, Emilio; Cormio, Luigi; Acquati, Pietro; DE Lorenzis, Elisa; Maugeri, Orazio; Arena, Giuseppe; Celia, Antonio; Giusti, Guido; Schips, Luigi

    2017-02-01

    Retrograde ureteroscopy (URS) has become a common procedure for the management of urinary stones. Although its efficacy and safety are well known, the literature about major complications is still poor. This study highlighted some cases of life-threatening complications after semirigid ureteroscopy (s-URS) or flexible ureteroscopy (f-URS). We enrolled experienced endourologists (more than 75 cases/year in the last 3 years) and we performed a survey asking to review their series and report the cases encumbered by major complications (Clavien-Dindo IIIb-IV grade). Eleven urologists reported on 12 major complications (4 after s-URS, 8 after f-URS). Eight patients developed a kidney injury, 1 an arteriovenous fistula, 2 a ureter avulsion and 1 acute sepsis. Six patients underwent open nephrectomy, two surgical repair, one open pyeloplasty, one coil artery embolization and two superselective artery embolization. Guidelines and clinical practice give useful recommendations about intraoperative safety and prevention of life-threatening events. The careful postoperative observation and the surgical active treatment of this complications play a key role in reducing morbidity, kidney loss and mortality. This study encourages a strict and active care of patients, supports a routine reporting of complications, and highlights the need for systematic use of standardized classification systems.

  3. [Survey of current situation of schistosomiasis health education in Wuxi City].

    Science.gov (United States)

    Meng, Xiao-jun; Gao, Dong-lin; Zhang, Xuan; Lu, Bing

    2015-04-01

    To understand the current situation of schistosomiasis health education in in Wuxi City where schistosomiasis transmission has been interrupted, so as to provide the evidence for formulating the health education strategies. Face to face interviews and a professional designed questionnaire were used to collect the information of the current schistosomiasis health education and investigate the awareness of schistosomiasis knowledge in primary and middle schools and in communities. The total awareness rate of schistosomiasis knowledge was 87.7% among 873 students and the figure was 83.0% among 693 community residents. The students who studied in the schools with more than 1 class hour of schistosomiasis health education, completed schistosomiasis health education material or teaching plan, and implementing health education through multiple ways had higher knowledge awareness rates compared with the schools without (χ2 = 291.408, 709.622, 13.751, all P education through broadcast/TV or square propaganda had a higher knowledge awareness rate compared with the communities without (χ2= 90.772, 47.436, all P education should be strengthened.

  4. Nationwide survey for current clinical status of amniocentesis and maternal serum marker test in Japan.

    Science.gov (United States)

    Miyake, Hidehiko; Yamada, Shigehito; Fujii, Yosuke; Sawai, Hideaki; Arimori, Naoko; Yamanouchi, Yasuko; Ozasa, Yuka; Kanai, Makoto; Sago, Haruhiko; Sekizawa, Akihiko; Takada, Fumio; Masuzaki, Hideaki; Matsubara, Yoichi; Hirahara, Fumiki; Kugu, Koji

    2016-10-01

    Prenatal testing has been provided in Japan over the past several decades. However, it is difficult to assess the clinical status of amniocentesis (AC) and maternal serum markers (MSM) because obstetricians can perform these tests without registration. This study aims to investigate the current clinical status of AC and MSM in Japan. We conducted a questionnaire study that was intended for a total of 5622 Japanese obstetrics/gynecology facilities during October 2013 to January 2014. The response rate was 40.8% (2295/5622). Of the 2295 facilities, 864 performed MSM (37.7%), 619 performed AC (27.0%) and 412 performed both (18.0%). The average number of MSM tests was 2.0 per month (range 0-52), and the average number of AC tests was 2.4 per month (range 0-30). Involvement of genetic professionals, such as clinical geneticists (CGs) and certified genetic counselors (CGCs), contribute to a content-rich explanation and management of difficult issues and lengthened the explanation time. Nevertheless, relatively few facilities employed these specialists (MSM: 96/864 and AC: 128/619). This is the first study to highlight the current clinical status of AC and MSM tests in Japan. Active involvement of CGs and CGCs can provide more appropriate genetic counseling for prenatal tests.

  5. Space-Based Thermal Infrared Studies of Asteroids

    CERN Document Server

    Mainzer, A; Trilling, D

    2015-01-01

    Large-area surveys operating at mid-infrared wavelengths have proven to be a valuable means of discovering and characterizing minor planets. Through the use of radiometric models, it is possible to derive physical properties such as diameters, albedos, and thermal inertia for large numbers of objects. Modern detector array technology has resulted in a significant improvement in spatial resolution and sensitivity compared with previous generations of space-based infrared telescopes, giving rise to a commensurate increase in the number of objects that have been observed at these wavelengths. Space-based infrared surveys of asteroids therefore offer an effective means of rapidly gathering information about small body populations' orbital and physical properties. The AKARI, WISE/NEOWISE, Spitzer, and Herschel missions have significantly increased the number of minor planets with well-determined diameters and albedos.

  6. SURVEY

    DEFF Research Database (Denmark)

    SURVEY er en udbredt metode og benyttes inden for bl.a. samfundsvidenskab, humaniora, psykologi og sundhedsforskning. Også uden for forskningsverdenen er der mange organisationer som f.eks. konsulentfirmaer og offentlige institutioner samt marketingsafdelinger i private virksomheder, der arbejder...... med surveys. Denne bog gennemgår alle surveyarbejdets faser og giver en praktisk indføring i: • design af undersøgelsen og udvælgelse af stikprøver, • formulering af spørgeskemaer samt indsamling og kodning af data, • metoder til at analysere resultaterne...

  7. Exploration of the Moon and Asteroids by Secondary Students (ExMASS): An Authentic, Open-Inquiry Research Experience for High School Students

    Science.gov (United States)

    Shaner, A. J.; Allen, J. S.; Shipp, S. S.; Kramer, G. Y.; Nahm, A.; Balazs, L.; Fuller, J.; Newland, J.; Snyder, R. D.; Kring, D. A.

    2014-12-01

    The National Research Council (2012) has expressed a need for participatory science experiences for students. Opportunities are needed for students which 1) allow them to understand how scientific knowledge develops and 2) can heighten their curiosity, capture their interest, and motivate their continued study of science. Studies (e.g., Aydeniz et al., 2011) have also recommend educators provide students with opportunities to do science through extracurricular work with scientists. In addition to being given the opportunity to fully participate in the scientific enterprise, students must also be explicitly guided in their attempts to develop a more appropriate understanding of the nature of the scientific enterprise (McDonald, 2010; Rudge & Howe, 2010; Yacoubian & BouJaoude, 2010). Exploration of the Moon and Asteroids by Secondary Students, or ExMASS, provides such an opportunity for students. The ExMASS program is an education effort managed by the LPI/NASA JSC-led Center for Lunar Science and Exploration (CLSE), one of nine teams comprising NASA's Solar System Exploration Research Virtual Institute (SSERVI). Over the course of one academic year, teams of high school students conduct their own scientific investigations of either Earth's Moon or asteroids, with guidance from a scientist mentor. The program includes two elements: 1) a guided inquiry introductory research activity that builds student knowledge of current lunar/asteroid science and lunar/asteroid data, and 2) an open inquiry research project in which the students apply their knowledge to a self-defined project. Evaluation data collected during the predecessor program to ExMASS revealed many successes, but also room for improvement. In response, an Advisory Group consisting of past teachers and mentors was formed to address the gaps revealed in the evaluation data. The ExMASS program will continue to collect similar evaluation data including assessment of changes in students' lunar/asteroid content

  8. Drinking water quality in household supply infrastructure--A survey of the current situation in Germany.

    Science.gov (United States)

    Völker, Sebastian; Schreiber, Christiane; Kistemann, Thomas

    2010-06-01

    As a result of the amendment to the German Drinking Water Ordinance in 2001, local public health authorities are obliged to monitor the water supply in installations providing water for public use (Section 18 German Drinking Water Ordinance). With a systematic and nationwide survey of locally available data relating to hygienic drinking water quality and the existing drinking water infrastructure in buildings, the extent of microbial contamination of in-building distribution systems in Germany is intended to be assessed. To gain an overview of the microbial contamination of drinking water in public buildings all 419 local public health authorities in Germany were contacted in 2007. In a detailed study with a representative cooperation level of 5% of these local public health authorities, the available data relating to microbiological, chemical, physical and technical parameters gained from in-building distribution systems were collected. Drinking water parameters were combined with regard to the total number of analyses and the absolute number as well as the percentage of limit compliance failures (n=108,288). Limits exceeded were classified as the failure to comply with the German Drinking Water Ordinance, DVGW technical regulations and Federal Environment Agency recommended limits. The highest rates of samples exceeding these limits were found for the parameter Legionella sp. which contaminated 12.8% of all samples (n=22,786; limit: 100 CFU/100ml), followed by heterotrophic plate count at 36 degrees C (3.5%, n=10,928; limit: 100 CFU/1 ml) and Pseudomonas sp. (2.9%, n=3468; limit: 0 CFU/100ml). Legionella sp. and Pseudomonas sp. pose a direct health risk to immunosuppressed users. Additionally, for some chemical parameters, such as nickel, iron and lead, a potential risk for the health of consumers was detected. Further data analysis may reveal whether this contamination is related to stagnation where there is only sporadic use or whether other factors are

  9. Production and use of biogas in Europe: a survey of current status and perspectives

    Directory of Open Access Journals (Sweden)

    Massimo Raboni

    2014-04-01

    Full Text Available The article presents the results of a survey carried out in the European Union (EU regarding the production and use of biogas from different sources. The EU is a world leader in the field of biogas, with a production of 10,085.8 ktoe y -1 (in 2011 in terms of primary energy, accounting for about 60% of the world’s production. Germany is the EU country that has made the greatest progress in this field with a production of as much as 5,067.6 ktoe y-1 , of which a share of 4,414.2 ktoe y-1 results from anaerobic digestion (and co-digestion processes of selected organic matrices. UK is the second largest producer with 1,764.8 ktoe y -1 , determined for 84% by landfill biogas and the remainder by biogas produced in sewage treatment plants (sludge digestion. Italy (1,095.7 ktoe y-1 and France (349.6 ktoe y -1 follow in the list of the largest producers. The trend of biogas production, in accordance with the action lines of the EU, is characterized by a progressive increase from anaerobic digestion (and co-digestion of selected organic matrices and a progressive decrease from landfills. Production in 2020 is estimated at 28.0 Mtoe y-1 in accordance with the EU Renewable Energy National Plans. The uses of biogas are mainly directed to the production of electricity and heat. There are, however, several cases of conversion of biogas into biomethane injected into the natural gas grids or used as biofuel in vehicles. In this last direction, worthy of note are a few north-central EU countries which have implemented an effective policy to promote the use of biomethane for public and private transport.

  10. Evolution History of Asteroid Itokawa Based on Block Distribution Analysis

    Science.gov (United States)

    Mazrouei, Sara; Daly, Michael; Barnouin, Olivier; Ernst, Carolyn

    2013-04-01

    This work investigates trends in the global and regional distribution of blocks on asteroid 25143 Itokawa in order to discover new findings to better understand the history of this asteroid. Itokawa is a near-Earth object, and the first asteroid that was targeted for a sample return mission. Trends in block population provide new insights in regards to Itokawa's current appearance following the disruption of a possible parent body, and how its surface might have changed since then. Here blocks are defined as rocks or features with distinctive positive relief that are larger than a few meters in size. The size and distribution of blocks are measured by mapping the outline of the blocks using the Small Body Mapping Tool (SBMT) created by the Johns Hopkins University Applied Physics Laboratory [1]. The SBMT allows the user to overlap correctly geo-located Hayabusa images [2] onto the Itokawa shape model. This study provides additional inferences on the original disruption and subsequent re-accretion of Itokawa's "head" and "body" from block analyses. A new approach is taken by analyzing the population of blocks with respect to latitude for both Itokawa's current state, and a hypothetical elliptical body. Itokawa currently rotates approximately about its maximum moment of inertia, which is expected due to conservation of momentum and minimum energy arguments. After the possible disruption of the parent body of Itokawa, the "body" of Itokawa would have tended to a similar rotation. The shape of this body is made by removing the head of Itokawa and applying a semispherical cap. Using the method of [3] inertial properties of this object are calculated. With the assumption that this object had settled to its stable rotational axis, it is found that the pole axis could have been tilted about 13° away from the current axis in the direction opposite the head, equivalent to a 33 meter change in the center of mass. The results of this study provide means to test the hypothesis

  11. Assessing the Age of an Asteroid's Surface with Data from the International Rosetta Mission

    Science.gov (United States)

    Lopez, Juan Carlos

    2011-01-01

    Rosetta is an international mission led by the European Space Agency (ESA) with key support and instrumentation from the National Aeronautics and Space Administration (NASA). Rosetta is currently on a ten-year mission to catch comet 67P/Churyumov-Gerasimenko (C-G); throughout its voyage, the spacecraft has performed flybys of two main belt asteroids (MBA): Steins and Lutetia. Data on the physical, chemical, and geological properties of these asteroids are currently being processed and analyzed. Accurate interpretation of such data is fundamental in the success of Rosetta's mission and overall objectives. Post-flyby data analyses strive to correlate the size, shape, volume, and rotational rate of Lutetia, in addition to interpreting its multi-color imagining, albedo, and spectral mapping. Although advancements in science have contributed to the examination of celestial bodies, methods to analyze asteroids remain largely empirical, not semi-empirical, nor ab initio. This study aims to interpret and document the scientific methods currently utilized in the characterization of asteroid (21) Lutetia in order to render these processes and methods accessible to the public. Examples include a standardized technique for assessing the age of an asteroid surface, complete with clickable reference maps, methodology of grouping surface characteristics together, and a standardized power law equation for the age. Other examples include determining the density of an object. Context for what both density and age mean is a bi-product of this study. Results of the study will aid in the development of pedagogical material on asteroids for public use, and in creation of an academic database for selected targets that might be used as a reference.

  12. Integrated science and engineering for the OSIRIS-REx asteroid sample return mission

    Science.gov (United States)

    Lauretta, D.

    2014-07-01

    Introduction: The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission will survey near-Earth asteroid (101955) Bennu to understand its physical, mineralogical, and chemical properties, assess its resource potential, refine the impact hazard, and return a sample of this body to the Earth [1]. This mission is scheduled for launch in 2016 and will rendezvous with the asteroid in 2018. Sample return to the Earth follows in 2023. The OSIRIS-REx mission has the challenge of visiting asteroid Bennu, characterizing it at global and local scales, then selecting the best site on the asteroid surface to acquire a sample for return to the Earth. Minimizing the risk of exploring an unknown world requires a tight integration of science and engineering to inform flight system and mission design. Defining the Asteroid Environment: We have performed an extensive astronomical campaign in support of OSIRIS-REx. Lightcurve and phase function observations were obtained with UA Observatories telescopes located in southeastern Arizona during the 2005--2006 and 2011--2012 apparitions [2]. We observed Bennu using the 12.6-cm radar at the Arecibo Observatory in 1999, 2005, and 2011 and the 3.5-cm radar at the Goldstone tracking station in 1999 and 2005 [3]. We conducted near-infrared measurements using the NASA Infrared Telescope Facility at the Mauna Kea Observatory in Hawaii in September 2005 [4]. Additional spectral observations were obtained in July 2011 and May 2012 with the Magellan 6.5-m telescope [5]. We used the Spitzer space telescope to observe Bennu in May 2007 [6]. The extensive knowledge gained as a result of our telescopic characterization of Bennu was critical in the selection of this object as the OSIRIS-REx mission target. In addition, we use these data, combined with models of the asteroid, to constrain over 100 different asteroid parameters covering orbital, bulk, rotational, radar

  13. Mitigation of Hazardous Comets and Asteroids

    Science.gov (United States)

    Belton, Michael J. S.; Morgan, Thomas H.; Samarasinha, Nalin H.; Yeomans, Donald K.

    2011-03-01

    Preface; 1. Recent progress in interpreting the nature of the near-Earth object population W. Bottke, A. Morbidelli and R. Jedicke; 2. Earth impactors: orbital characteristics and warning times S. R. Chesley and T. B. Spahr; 3. The role of radar in predicting and preventing asteroid and comet collisions with Earth S. J. Ostro and J. D. Giorgini; 4. Interior structures for asteroids and cometary nuclei E. Asphaug; 5. What we know and don't know about surfaces of potentially hazardous small bodies C. R. Chapman; 6. About deflecting asteroids and comets K. A. Holsapple; 7. Scientific requirements for understanding the near-Earth asteroid population A. W. Harris; 8. Physical properties of comets and asteroids inferred from fireball observations M. D. Martino and A. Cellino; 9. Mitigation technologies and their requirements C. Gritzner and R. Kahle; 10. Peering inside near-Earth objects with radio tomography W. Kofman and A. Safaeinili; 11. Seismological imvestigation of asteroid and comet interiors J. D. Walker and W. F. Huebner; 12. Lander and penetrator science for near-Earth object mitigation studies A. J. Ball, P. Lognonne, K. Seiferlin, M. Patzold and T. Spohn; 13. Optimal interpretation and deflection of Earth-approaching asteroids using low-thrust electric propulsion B. A. Conway; 14. Close proximity operations at small bodies: orbiting, hovering, and hopping D. J. Scheeres; 15. Mission operations in low gravity regolith and dust D. Sears, M. Franzen, S. Moore, S. Nichols, M. Kareev and P. Benoit; 16. Impacts and the public: communicating the nature of the impact hazard D. Morrison, C. R. Chapman, D. Steel and R. P. Binzel; 17. Towards a program to remove the threat of hazardous NEOs M. J. S. Belton.

  14. Using Dust from Asteroids as Regolith Microsamples

    Science.gov (United States)

    Cohen, B. A.; Klima, Rachel; Chabot, N. L.; Rivkin, A. S.

    2015-01-01

    Meteorite science is rich with compositional indicators by which we classify parent bodies, but few sample groups are definitively linked with asteroid spectra. More robust links need to be forged between meteorites and their parent bodies to understand the composition, diversity and distribution. A major link can be sample analysis of the parent body material and comparison with meteorite data. Hayabusa, the first sample return mission of the Japanese Aerospace Exploration Agency (JAXA), was developed to rendezvous with and collect samples from asteroid Itokawa and return them to Earth. Thousands of sub-100 micron particles were recovered, apparently introduced during the spacecraft impact into the surface of the asteroid, linking the asteroid Itokawa to LL chondrites [1]. Upcoming missions Hayabusa 2 and OSIRIS-REx will collect more significant sample masses from asteroids. In all these cases, the samples are or will be a collection of regolith particles. Sample return to earth is not the only method for regolith particle analysis. Dust is present around all airless bodies, generated by micrometeorite impact into their airless surfaces, which in turn lofts regolith particles into a "cloud" around the body. The composition, flux, and size-frequency distribution of dust particles can provide significant insight into the geological evolution of airless bodies [2]. For example, the Cassini Cosmic Dust Analyzer (CDA) detected salts in Enceladus' icy plume material, providing evidence for a subsurface ocean in contact with a silicate seafloor [3]. Similar instruments have flown on the Rosetta, LADEE, and Stardust missions. Such an instrument may be of great use in obtaining the elemental, isotopic and mineralogical composition measurement of dust particles originating from asteroids without returning the samples to terrestrial laboratories. We investigated the ability of a limited sample analysis capability using a dust instrument to forge links between asteroid

  15. A survey of current trends in diffusion MRI for structural brain connectivity

    Science.gov (United States)

    Ghosh, Aurobrata; Deriche, Rachid

    2016-02-01

    In this paper, we review the state of the art in diffusion magnetic resonance imaging (dMRI) and we present current trends in modelling the brain's tissue microstructure and the human connectome. dMRI is today the only tool that can probe the brain's axonal architecture in vivo and non-invasively, and has grown in leaps and bounds in the last two decades since its conception. A plethora of models with increasing complexity and better accuracy have been proposed to characterise the integrity of the cerebral tissue, to understand its microstructure and to infer its connectivity. Here, we discuss a wide range of the most popular, important and well-established local microstructure models and biomarkers that have been proposed from these models. Finally, we briefly present the state of the art in tractography techniques that allow us to understand the architecture of the brain's connectivity.

  16. A survey of the current status of web-based databases indexing Iranian journals.

    Science.gov (United States)

    Merat, Shahin; Khatibzadeh, Shahab; Mesgarpour, Bita; Malekzadeh, Reza

    2009-05-01

    The scientific output of Iran is increasing rapidly during the recent years. Unfortunately, most papers are published in journals which are not indexed by popular indexing systems and many of them are in Persian without English translation. This makes the results of Iranian scientific research unavailable to other researchers, including Iranians. The aim of this study was to evaluate the quality of current web-based databases indexing scientific articles published in Iran. We identified web-based databases which indexed scientific journals published in Iran using popular search engines. The sites were then subjected to a series of tests to evaluate their coverage, search capabilities, stability, accuracy of information, consistency, accessibility, ease of use, and other features. Results were compared with each other to identify strengths and shortcomings of each site. Five web sites were indentified. None had a complete coverage on scientific Iranian journals. The search capabilities were less than optimal in most sites. English translations of research titles, author names, keywords, and abstracts of Persian-language articles did not follow standards. Some sites did not cover abstracts. Numerous typing errors make searches ineffective and citation indexing unreliable. None of the currently available indexing sites are capable of presenting Iranian research to the international scientific community. The government should intervene by enforcing policies designed to facilitate indexing through a systematic approach. The policies should address Iranian journals, authors, and indexing sites. Iranian journals should be required to provide their indexing data, including references, electronically; authors should provide correct indexing information to journals; and indexing sites should improve their software to meet standards set by the government.

  17. Current trends of management of respiratory diseases by pulmonologists: Results of National Conference of Pulmonary Disease - 2015 survey

    Directory of Open Access Journals (Sweden)

    Sheetu Singh

    2017-01-01

    Full Text Available Context: Respiratory diseases are a common problem in our country and these are associated with significant morbidity and mortality. Aims: The aim of the paper was to analyze the pattern of diagnostic tests used and treatment prescribed for common respiratory diseases. Settings and Design: A total of 1028 pulmonologists, either member of Indian Chest Society or delegate attending the National Conference of Pulmonary Diseases (NAPCON 2015, participated in the online survey. Subjects and Methods: The survey included questions pertinent to common respiratory diseases such as pulmonary tuberculosis (PTB, bronchial asthma, chronic obstructive pulmonary disease (COPD, idiopathic pulmonary fibrosis (IPF, and pneumonia. Results: Investigation used for severity assessment and diagnosis of PTB, was sputum for acid-fast bacilli (83.5%, for IPF was high-resolution computed tomography chest (85.6%, for severe pneumonia was arterial blood gas analysis (69.3%, for asthma was spirometery and peak flow (96.8% and for COPDs was spirometry (87.2%. The most popular choice of treatment for PTB was directly observed treatment short course (55.7%, for bronchial asthma, it was long-acting beta agonist with inhaled corticosteroids (LABA + ICSs (41.1%, for COPD, it was LABA, ICS, and long-acting muscarinic antagonist (LABA + ICS + long-acting muscarinic antagonist (32.4% and for IPF, it was pirfenidone and N acetyl cysteine (38.3%. About 67.5% of doctors preferred hospitalization for patients with severe pneumonia. About 84.5% pulmonologists ordered diagnostic tests and 55.5% prescribed treatment as per current guidelines. Conclusions: The majority of doctors (70.1% in our survey followed recommended guidelines for respiratory disease diagnosis and treatment. However, there is a need for upgradation of treatment strategies currently used by doctors.

  18. Current trends of management of respiratory diseases by pulmonologists: Results of National Conference of Pulmonary Disease - 2015 survey

    Science.gov (United States)

    Singh, Sheetu; Singh, Nishtha

    2017-01-01

    Context: Respiratory diseases are a common problem in our country and these are associated with significant morbidity and mortality. Aims: The aim of the paper was to analyze the pattern of diagnostic tests used and treatment prescribed for common respiratory diseases. Settings and Design: A total of 1028 pulmonologists, either member of Indian Chest Society or delegate attending the National Conference of Pulmonary Diseases (NAPCON) 2015, participated in the online survey. Subjects and Methods: The survey included questions pertinent to common respiratory diseases such as pulmonary tuberculosis (PTB), bronchial asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and pneumonia. Results: Investigation used for severity assessment and diagnosis of PTB, was sputum for acid-fast bacilli (83.5%), for IPF was high-resolution computed tomography chest (85.6%), for severe pneumonia was arterial blood gas analysis (69.3%), for asthma was spirometery and peak flow (96.8%) and for COPDs was spirometry (87.2%). The most popular choice of treatment for PTB was directly observed treatment short course (55.7%), for bronchial asthma, it was long-acting beta agonist with inhaled corticosteroids (LABA + ICSs) (41.1%), for COPD, it was LABA, ICS, and long-acting muscarinic antagonist (LABA + ICS + long-acting muscarinic antagonist) (32.4%) and for IPF, it was pirfenidone and N acetyl cysteine (38.3%). About 67.5% of doctors preferred hospitalization for patients with severe pneumonia. About 84.5% pulmonologists ordered diagnostic tests and 55.5% prescribed treatment as per current guidelines. Conclusions: The majority of doctors (70.1%) in our survey followed recommended guidelines for respiratory disease diagnosis and treatment. However, there is a need for upgradation of treatment strategies currently used by doctors. PMID:28144054

  19. Appraisal of donor steatosis in liver transplantation: a survey of current practice in Australia and New Zealand

    Directory of Open Access Journals (Sweden)

    Dare AJ

    2012-12-01

    Full Text Available Anna J Dare,1 Anthony RJ Phillips,1–3 Michael Chu,1 Anthony JR Hickey,2 Adam SJR Bartlett1–31Department of Surgery, 2Maurice Wilkins Centre for Biodiscovery, University of Auckland, Auckland, New Zealand; 3New Zealand Liver Transplant Unit, Auckland City Hospital, Auckland, New ZealandBackground: Hepatic steatosis is increasingly encountered among organ donors. Currently, there is no consensus guideline as to the type or degree of donor steatosis considered acceptable for liver transplantation (LT, and little is known about local practices in this area. The aim of this survey was to evaluate current clinical practices amongst liver transplant surgeons in Australia and New Zealand (ANZ in the evaluation