Sample records for zodiac tessellation improved

  1. Research on tessellation with triangle strip

    NASA Astrophysics Data System (ADS)

    Yu, Li; Zhang, Huaisheng

    2018-04-01

    The tessellation module of graphics pipeline can generate many triangles to specify surface detail characteristics, which are usually organized in triangle lists. However, the number of generated vertices is large and there are many repeated vertices. This paper proposes a new tessellation approach of triangle strips, which makes use of the adjacent relationship among triangles. It decreases the number of generated vertices which will benefits latter computation and storage. Experiments show that the number of generated vertices by the strip approach is about 51% of traditional triangle lists, which can improve the performance of GPU tessellation.

  2. Application of Tessellation in Architectural Geometry Design

    NASA Astrophysics Data System (ADS)

    Chang, Wei

    2018-06-01

    Tessellation plays a significant role in architectural geometry design, which is widely used both through history of architecture and in modern architectural design with the help of computer technology. Tessellation has been found since the birth of civilization. In terms of dimensions, there are two- dimensional tessellations and three-dimensional tessellations; in terms of symmetry, there are periodic tessellations and aperiodic tessellations. Besides, some special types of tessellations such as Voronoi Tessellation and Delaunay Triangles are also included. Both Geometry and Crystallography, the latter of which is the basic theory of three-dimensional tessellations, need to be studied. In history, tessellation was applied into skins or decorations in architecture. The development of Computer technology enables tessellation to be more powerful, as seen in surface control, surface display and structure design, etc. Therefore, research on the application of tessellation in architectural geometry design is of great necessity in architecture studies.

  3. The exo-zodiacal disk mapper

    NASA Technical Reports Server (NTRS)

    Petro, Larry; Bely, P.; Burg, R.; Wade, L.; Beichman, C.; Gay, J.; Baudoz, P.; Rabbia, Y.; Perrin, J. M.

    1998-01-01

    Zodiacal dust around neighboring stars could obscure the signal of terrestrial planets observed with the Terrestrial Planet Finder (TPF) if that dust is similar to that in the Solar System. Unfortunately, little is known about the presence, or frequency of occurrence of zodiacal dust around stars and so the relevance of zodiacal dust to the design of the TPF, or to the TPF mission, is unknown. It is likely that direct observation of zodiacal dust disks will be necessary to confidently determine the characteristics of individual systems. A survey of a large number of stars in the solar neighborhood that could be candidates for observation with TPF should be undertaken. We present a concept for a space mission to undertake a sensitive, large-scale survey capable of characterizing solar-system-like zodiacal dust around 400 stars within 20 pc of the Sun.

  4. COSMIC INFRARED BACKGROUND FLUCTUATIONS AND ZODIACAL LIGHT

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.

    We performed a specific observational test to measure the effect that the zodiacal light can have on measurements of the spatial fluctuations of the near-IR background. Previous estimates of possible fluctuations caused by zodiacal light have often been extrapolated from observations of the thermal emission at longer wavelengths and low angular resolution or from IRAC observations of high-latitude fields where zodiacal light is faint and not strongly varying with time. The new observations analyzed here target the COSMOS field at low ecliptic latitude where the zodiacal light intensity varies by factors of ∼2 over the range of solar elongations atmore » which the field can be observed. We find that the white-noise component of the spatial power spectrum of the background is correlated with the modeled zodiacal light intensity. Roughly half of the measured white noise is correlated with the zodiacal light, but a more detailed interpretation of the white noise is hampered by systematic uncertainties that are evident in the zodiacal light model. At large angular scales (≳100″) where excess power above the white noise is observed, we find no correlation of the power with the modeled intensity of the zodiacal light. This test clearly indicates that the large-scale power in the infrared background is not being caused by the zodiacal light.« less

  5. Cosmic Infrared Background Fluctuations and Zodiacal Light

    NASA Astrophysics Data System (ADS)

    Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

    2016-06-01

    We performed a specific observational test to measure the effect that the zodiacal light can have on measurements of the spatial fluctuations of the near-IR background. Previous estimates of possible fluctuations caused by zodiacal light have often been extrapolated from observations of the thermal emission at longer wavelengths and low angular resolution or from IRAC observations of high-latitude fields where zodiacal light is faint and not strongly varying with time. The new observations analyzed here target the COSMOS field at low ecliptic latitude where the zodiacal light intensity varies by factors of ˜2 over the range of solar elongations at which the field can be observed. We find that the white-noise component of the spatial power spectrum of the background is correlated with the modeled zodiacal light intensity. Roughly half of the measured white noise is correlated with the zodiacal light, but a more detailed interpretation of the white noise is hampered by systematic uncertainties that are evident in the zodiacal light model. At large angular scales (≳100″) where excess power above the white noise is observed, we find no correlation of the power with the modeled intensity of the zodiacal light. This test clearly indicates that the large-scale power in the infrared background is not being caused by the zodiacal light.

  6. Cosmic Infrared Background Fluctuations and Zodiacal Light

    NASA Technical Reports Server (NTRS)

    Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

    2017-01-01

    We performed a specific observational test to measure the effect that the zodiacal light can have on measurements of the spatial fluctuations of the near-IR (near-infrared)background. Previous estimates of possible fluctuations caused by zodiacal light have often been extrapolated from observations of the thermal emission at longer wavelengths and low angular resolution or from IRAC (Infrared Array Camera) observations of high-latitude fields where zodiacal light is faint and not strongly varying with time. The new observations analyzed here target the COSMOS (Cosmic Evolution Survey) field at low ecliptic latitude where the zodiacal light intensity varies by factors of approximately 2 over the range of solar elongations at which the field can be observed. We find that the white-noise component of the spatial power spectrum of the background is correlated with the modeled zodiacal light intensity. Roughly half of the measured white noise is correlated with the zodiacal light, but a more detailed interpretation of the white noise is hampered by systematic uncertainties that are evident in the zodiacal light model. At large angular scales (greater than or approximately equal to 100 arcseconds) where excess power above the white noise is observed, we find no correlation of the power with the modeled intensity of the zodiacal light. This test clearly indicates that the large-scale power in the infrared background is not being caused by the zodiacal light.

  7. Rigidly foldable origami gadgets and tessellations

    PubMed Central

    Evans, Thomas A.; Lang, Robert J.; Magleby, Spencer P.; Howell, Larry L.

    2015-01-01

    Rigidly foldable origami allows for motion where all deflection occurs at the crease lines and facilitates the application of origami in materials other than paper. In this paper, we use a recently discovered method for determining rigid foldability to identify existing flat-foldable rigidly foldable tessellations, which are also categorized. We introduce rigidly foldable origami gadgets which may be used to modify existing tessellations or to create new tessellations. Several modified and new rigidly foldable tessellations are presented. PMID:26473037

  8. A Chinese Zodiac Mathematical Structure.

    ERIC Educational Resources Information Center

    Lamb, John F., Jr.

    2000-01-01

    Helps students identify the animal that corresponds to the year of their birth according to the Chinese zodiac. Defines the structure of the Chinese zodiac so that the subsets of compatibles and opposites form closed substructures with interesting mathematical properties. (ASK)

  9. Zodiac II: Debris Disk Imaging Potential

    NASA Technical Reports Server (NTRS)

    Traub Wesley; Bryden, Geoff; Stapelfeldt, Karl; Chen, Pin; Trauger, John

    2011-01-01

    Zodiac II is a proposed coronagraph on a balloon-borne platform, for the purpose of observing debris disks around nearby stars. Zodiac II will have a 1.2-m diameter telescope mounted in a balloon-borne gondola capable of arcsecond quality pointing, and with the capability to make long-duration (several week) flights. Zodiac II will have a coronagraph able to make images of debris disks, meaning that its scattered light speckles will be at or below an average contrast level of about 10(exp -7) in three narrow (7 percent) bands centered on the V band, and one broad (20%) one at I band. We will discuss the potential science to be done with Zodiac II.

  10. Acoustic Wave Guiding by Reconfigurable Tessellated Arrays

    NASA Astrophysics Data System (ADS)

    Zou, Chengzhe; Lynd, Danielle T.; Harne, Ryan L.

    2018-01-01

    The reconfiguration of origami tessellations is a prime vehicle to harness for adapting system properties governed by a structural form. While the knowledge of mechanical property changes associated with origami tessellation folding has been extensively built up, the opportunities to integrate other physics into a framework of tessellated, adaptive structures remain to be fully exploited. Acoustics appears to be a prime domain to marry with origami science. Specifically, deep technical analogies are revealed between wave-guiding properties achieved via digital methods that virtually reposition array elements and the actual repositioning of facets by folding origami-inspired tessellations. Here we capitalize on this analogy to investigate acoustic arrays established upon facet layouts of origami-inspired tessellations. We show that a concept of reconfigurable tessellated arrays may guide waves more effectively than traditional digitally phased arrays using fewer transducer elements. Moreover, we show that the refinement of tessellated arrays trends to the ideal case of classical wave radiators or receivers grounded in principles of geometrical acoustics. By linear wave physics shared among myriad scientific disciplines and across orders of magnitude in length scale, these discoveries may cultivate numerous opportunities for wave-guiding adaptive structures inspired by low-dimensional origami tessellations.

  11. Dynamical Zodiacal Cloud Models Constrained by High Resolution Spectroscopy of the Zodiacal Light

    NASA Technical Reports Server (NTRS)

    Ipatov, S. I.; Kutyrev, A. S.; Madsen, G. J.; Mather, J. C.; Moseley, S. H.; Reynolds, R. J.

    2005-01-01

    We have developed a set of self-consistent dynamical models of the Zodiacal cloud, following the orbital evolution of dust particles. Three populations were considered, originating from the Kuiper belt, asteroids and comets. Using the models developed, we investigated how the solar spectrum is changed by scattering by the zodiacal cloud grains and compared the obtained spectra with the observations.

  12. Tessellating the Sphere with Regular Polygons

    ERIC Educational Resources Information Center

    Soto-Johnson, Hortensia; Bechthold, Dawn

    2004-01-01

    Tessellations in the Euclidean plane and regular polygons that tessellate the sphere are reviewed. The regular polygons that can possibly tesellate the sphere are spherical triangles, squares and pentagons.

  13. A study of zodiacal light models

    NASA Technical Reports Server (NTRS)

    Gary, G. A.; Craven, P. D.

    1973-01-01

    A review is presented of the basic equations used in the analysis of photometric observations of zodiacal light. A survey of the methods used to model the zodiacal light in and out of the ecliptic is given. Results and comparison of various models are presented, as well as recent results by the authors.

  14. Zodiacal light as an indicator of interplanetary dust

    NASA Technical Reports Server (NTRS)

    Weinberg, J. L.; Sparrow, J. G.

    1978-01-01

    The most striking feature of the night sky in the tropics is the zodiacal light, which appears as a cone in the west after sunset and in the east before sunrise. It is caused by sunlight scattered or absorbed by particles in the interplanetary medium. The zodiacal light is the only source of information about the integrated properties of the whole ensemble of interplanetary dust. The brightness and polarization in different directions and at different colors can provide information on the optical properties and spatial distribution of the scattering particles. The zodiacal light arises from two independent physical processes related to the scattering of solar continuum radiation by interplanetary dust and to thermal emission which arises from solar radiation that is absorbed by interplanetary dust and reemitted mainly at infrared wavelengths. Attention is given to observational parameters of zodiacal light, the methods of observation, errors and absolute calibration, and the observed characteristics of zodiacal light.

  15. Zodiac II: Debris Disk Science from a Balloon

    NASA Technical Reports Server (NTRS)

    Bryden, Geoffrey; Traub, Wesley; Roberts, Lewis C., Jr.; Bruno, Robin; Unwin, Stephen; Backovsky, Stan; Brugarolas, Paul; Chakrabarti, Supriya; Chen, Pin; Hillenbrand, Lynne; hide

    2011-01-01

    Zodiac II is a proposed balloon-borne science investigation of debris disks around nearby stars. Debris disks are analogs of the Asteroid Belt (mainly rocky) and Kuiper Belt (mainly icy) in our Solar System. Zodiac II will measure the size, shape, brightness, and color of a statistically significant sample of disks. These measurements will enable us to probe these fundamental questions: what do debris disks tell us about the evolution of planetary systems; how are debris disks produced; how are debris disks shaped by planets; what materials are debris disks made of; how much dust do debris disks make sa they grind down; and how long do debris disks live? In addition, Zodiac II will observe hot, young exoplanets as targets of opportunity. The Zodiac II instrument is a 1.1-m diameter SiC telescope and an imaging coronagraph on a gondola carried by a stratospheric balloon. Its data product is a set of images of each targeted debris disk in four broad visible wavelength bands. Zodiac II will address its science questions by taking high-resolution, multi-wavelength images of the debris disks around tens of nearby stars. Mid-latitude flights are considered: overnight test flights within the United States followed by half-global flights in the Southern Hemisphere. These longer flights are required to fully explore the set of known debris disks accessible only to Zodiac II. On these targets, it will be 100 times more sensitive than the Hubble Space Telescope's Advanced Camera for Surveys (HST/ACS); no existing telescope can match the Zodiac II contrast and resolution performance. A second objective of Zodiac II is to use the near-space environment to raise the Technology Readiness Level (TRL) of SiC mirrors, internal coronagraphs, deformable mirrors, and wavefront sensing and control, all potentially needed for a future space-based telescope for high-contrast exoplanet imaging.

  16. Zodiac II: Debris Disk Science from a Balloon

    NASA Technical Reports Server (NTRS)

    Bryden, Geoffrey; Traub, Wesley; Roberts, Lewis C., Jr.; Bruno, Robin; Unwin, Stephen; Backovsky, Stan; Brugarolas, Paul; Chakrabarti, Supriya; Chen, Pin; Hillenbrand, Lynne; hide

    2011-01-01

    Zodiac II is a proposed balloon-borne science investigation of debris disks around nearby stars. Debris disks are analogs of the Asteroid Belt (mainly rocky) and Kuiper Belt (mainly icy) in our Solar System. Zodiac II will measure the size, shape, brightness, and color of a statistically significant sample of disks. These measurements will enable us to probe these fundamental questions: what do debris disks tell us about the evolution of planetary systems; how are debris disks produced; how are debris disks shaped by planets; what materials are debris disks made of; how much dust do debris disks make as they grind down; and how long do debris disks live? In addition, Zodiac II will observe hot, young exoplanets as targets of opportunity. The Zodiac II instrument is a 1.1-m diameter SiC (Silicone carbide) telescope and an imaging coronagraph on a gondola carried by a stratospheric balloon. Its data product is a set of images of each targeted debris disk in four broad visible-wavelength bands. Zodiac II will address its science questions by taking high-resolution, multi-wavelength images of the debris disks around tens of nearby stars. Mid-latitude flights are considered: overnight test flights in the US followed by half-global flights in the Southern Hemisphere. These longer flights are required to fully explore the set of known debris disks accessible only to Zodiac II. On these targets, it will be 100 times more sensitive than the Hubble Space Telescope's Advanced Camera for Surveys (HST/ACS); no existing telescope can match the Zodiac II contrast and resolution performance. A second objective of Zodiac II is to use the near-space environment to raise the Technology Readiness Level (TRL) of SiC mirrors, internal coronagraphs, deformable mirrors, and wavefront sensing and control, all potentially needed for a future space-based telescope for high-contrast exoplanet imaging.

  17. The Dynamic Community of Interest and Its Realization in ZODIAC

    DTIC Science & Technology

    2009-10-01

    the ZODIAC project. ZODIAC is a network architecture that puts security first and foremost, with security broken down into confidentiality, integrity...hosts, a unified solution for MANETs will work for hosts or routers as well. DYNAMIC COMMUNITIES OF INTEREST The basis of the ZODIAC design is a new dis...narrow scope of each DCoI limits attack propagation, and supports confidentiality ABSTRACT The ZODIAC project has been exploring a security first

  18. The review on tessellation origami inspired folded structure

    NASA Astrophysics Data System (ADS)

    Chu, Chai Chen; Keong, Choong Kok

    2017-10-01

    Existence of folds enhances the load carrying capacity of a folded structure which makes it suitable to be used for application where large open space is required such as large span roof structures and façade. Folded structure is closely related to origami especially the tessellation origami. Tessellation origami provides a folded configuration with facetted surface as a result from repeated folding pattern. Besides that, tessellation origami has flexible folding mechanism that produced a variety of 3-dimensional folded configurations. Despite the direct relationship between fold in origami and folded structure, the idea of origami inspired folded structure is not properly reviewed in the relevant engineering field. Hence, this paper aims to present the current studies from related discipline which has direct relation with application of tessellation origami in folded structure. First, tessellation origami is properly introduced and defined. Then, the review covers the topic on the origami tessellation design suitable for folded structure, its modeling and simulation method, and existing studies and applications of origami as folded structure is presented. The paper also includes the discussion on the current issues related to each topic.

  19. A Near-Infrared Spectrometer to Measure Zodiacal Light Absorption Spectrum

    NASA Technical Reports Server (NTRS)

    Kutyrev, A. S.; Arendt, R.; Dwek, E.; Kimble, R.; Moseley, S. H.; Rapchun, D.; Silverberg, R. F.

    2010-01-01

    We have developed a high throughput infrared spectrometer for zodiacal light fraunhofer lines measurements. The instrument is based on a cryogenic dual silicon Fabry-Perot etalon which is designed to achieve high signal to noise Fraunhofer line profile measurements. Very large aperture silicon Fabry-Perot etalons and fast camera optics make these measurements possible. The results of the absorption line profile measurements will provide a model free measure of the zodiacal Light intensity in the near infrared. The knowledge of the zodiacal light brightness is crucial for accurate subtraction of zodiacal light foreground for accurate measure of the extragalactic background light after the subtraction of zodiacal light foreground. We present the final design of the instrument and the first results of its performance.

  20. The NGST and the Zodiacal Light in the Solar System

    NASA Technical Reports Server (NTRS)

    Gorkavyi, Nick; Ozernoy, Leonid; Mather, John; Taidakova, Tanya

    1999-01-01

    We develop a physical model of the zodiacal cloud incorporating the real dust sources of asteroidal, cometary, and kuiperoidal origin. Using the inferred distribution of the zodiacal dust, we compute its thermal emission and scattering at several wavelengths (1.25, 5, and 20 micron) as a function of NGST location assumed to be at 1 AU or 3 AU. Areas on the sky with a minimum of zodiacal light are determined.

  1. Observations of the zodiacal light from the ecliptic to the poles.

    NASA Technical Reports Server (NTRS)

    Sparrow, J. G.; Ney, E. P.

    1972-01-01

    The brightness and polarization of the zodiacal light have been measured from the satellite OSO-5, using two photometers of effective wavelengths 4180 and 6820 A. The satellite configuration restricts the observations to ecliptic longitudes close to 90 deg, but measurements have been made from the ecliptic to the poles. On the ecliptic, the intensity of the zodiacal light was found to be 117 S10 (blue) and 315 S10 (red) with polarizations of 16.5 and 15 per cent, respectively. At the ecliptic poles the zodiacal intensity was 35 S10 (blue) with 20 per cent polarization. No temporal changes in zodiacal light have been found nor any significant differences in the intensities in the two hemispheres. The direction of polarization of the zodiacal light has been shown to be H-pass radial.

  2. Voronoi Tessellations and Their Application to Climate and Global Modeling

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ju, Lili; Ringler, Todd; Gunzburger, Max

    2011-01-01

    We review the use of Voronoi tessellations for grid generation, especially on the whole sphere or in regions on the sphere. Voronoi tessellations and the corresponding Delaunay tessellations in regions and surfaces on Euclidean space are defined and properties they possess that make them well-suited for grid generation purposes are discussed, as are algorithms for their construction. This is followed by a more detailed look at one very special type of Voronoi tessellation, the centroidal Voronoi tessellation (CVT). After defining them, discussing some of their properties, and presenting algorithms for their construction, we illustrate the use of CVTs for producingmore » both quasi-uniform and variable resolution meshes in the plane and on the sphere. Finally, we briefly discuss the computational solution of model equations based on CVTs on the sphere.« less

  3. [Signs of the zodiac and personality].

    PubMed

    Angst, J; Scheidegger, P

    1976-01-01

    3074 young men resident in the canton of Zurich, representing 50% of the 19 year old male population, form the fully representative sample of our large scale investigation. We investigated whether personality traits measured by means of the differentiated "Freiburger personality inventory" (FPI) could in any way be correlated to the signs of the zodiac under which the young men were born. The statistical analysis did not reveal any correlation between signs of the zodiac and personality. The claim made by astrologers that people can be characterized according to their sign of the zodiac (sagitarius, taurus, cancer, scorpion) must be refuted. Of course the astrologically founded description of human personality does not base itself on the position of the sun only, however the latter does form a very essential part of the astrological evaluation of people. This, at any rate has been shown to be without any scientific basis. The fact that astrological evaluation of human personality is so popular nowadays can be explained by the fact that even modern people are inclined towards magical thinking.

  4. USING DIRICHLET TESSELLATION TO HELP ESTIMATE MICROBIAL BIOMASS CONCENTRATIONS

    EPA Science Inventory

    Dirichlet tessellation was applied to estimate microbial concentrations from microscope well slides. The use of microscopy/Dirichlet tessellation to quantify biomass was illustrated with two species of morphologically distinct cyanobacteria, and validated empirically by compariso...

  5. Tiling, Tessellating and Quilting.

    ERIC Educational Resources Information Center

    Young, Sandy

    1994-01-01

    Describes a three-week unit that explores the mathematical concept of spatial sense through literature books, moving from activities of tiling, to tessellation, to quilting, and ending with transfer of patterns to T-shirts. (BB)

  6. Escher's Tessellations in Understanding Group Theory

    ERIC Educational Resources Information Center

    Konyalioglu, Serpil

    2009-01-01

    In this study, it is explained how to use Escher's tessellations in teaching group concept which is one of the most abstract concepts in mathematics. MC Escher's monohedral tessellations provide detailed study in an undergraduate course in abstract algebra. This study attempts to provide useful visual references for the students on learning some…

  7. OAO-2 observations of the zodiacal light

    NASA Technical Reports Server (NTRS)

    Lillie, C. F.

    1972-01-01

    Photometric measurements of the night sky brightness have been obtained at twelve wavelengths between 1000 A and 4300 A from above the earth's atmosphere. A preliminary analysis of the data reveals a component of the sky brightness with ecliptic symmetry and an intensity distribution similar to that of the zodiacal light. The ultraviolet spectrum of the zodiacal light can be closely approximated with a two component model in which one component has an albedo proportional to the wavelength lambda and the other component has a scattering efficiency proportional to lambda to lbe minus 19 power.

  8. Zodiacal light and the asteroid belt - The view from Pioneer 10

    NASA Technical Reports Server (NTRS)

    Hanner, M. S.; Weinberg, J. L.; Deshields, L. M., II; Green, B. A.; Toller, G. N.

    1974-01-01

    Brightnesses measured by the Pioneer 10 imaging photopolarimeter in two regions of sky were compared on sky maps at sun-spacecraft distances from 2.4 to 4.8 AU to determine the spatial extent of the zodiacal light. Data in the ecliptic at elongations greater than 90 deg show negligible contribution to the zodiacal light beyond 3.3 AU, the 2:1 Jupiter resonance. The zodiacal light brightness at 2.4 AU is less than 10% of that observed at 1 AU.

  9. PARAVT: Parallel Voronoi tessellation code

    NASA Astrophysics Data System (ADS)

    González, R. E.

    2016-10-01

    In this study, we present a new open source code for massive parallel computation of Voronoi tessellations (VT hereafter) in large data sets. The code is focused for astrophysical purposes where VT densities and neighbors are widely used. There are several serial Voronoi tessellation codes, however no open source and parallel implementations are available to handle the large number of particles/galaxies in current N-body simulations and sky surveys. Parallelization is implemented under MPI and VT using Qhull library. Domain decomposition takes into account consistent boundary computation between tasks, and includes periodic conditions. In addition, the code computes neighbors list, Voronoi density, Voronoi cell volume, density gradient for each particle, and densities on a regular grid. Code implementation and user guide are publicly available at https://github.com/regonzar/paravt.

  10. Voyages of the Zodiac, an Impenitent Traveller across Lands and Ages

    NASA Astrophysics Data System (ADS)

    Belmonte, Juan Antonio

    2015-05-01

    The zodiac is one of humankind's oldest astronomical heritages. Indeed, it has a long history and had an impressive cultural influence in the past that could be traced from the steppes of Mesopotamia to the wilderness of the Roman frontiers in Great Britain. In the present essay, we will discuss the origin of the zodiacal constellations in ancient Mesopotamia from their possible prehistoric ancestors in the pre-ceramic context of the 10,000-year-old site of Göbleki Tepe. Later on, we will discuss the role that the zodiac played in the development of the new cult established by King Antiochos I of Commagene in his hierothesion at Nemrud Dag, where a planetary conjunction in Leo has played a role in the clues to understand the enigmas of such an impressive monument. This will be followed by the analysis of its southwards travel to the Valley of the Nile, where we will study the famous Zodiac of Dendera. Then we will travel westwards to discuss the astronomical aspects of a new religion where astronomical eras and the zodiac ought to play a most relevant role, Mithraism. Finally, new ideas for future research in this most interesting topic will briefly be sketched.

  11. Pioneer 10 observations of zodiacal light brightness near the ecliptic - Changes with heliocentric distance

    NASA Technical Reports Server (NTRS)

    Hanner, M. S.; Weinberg, J. L.; Beeson, D. E.; Sparrow, J. G.

    1976-01-01

    Sky maps made by the Pioneer 10 Imaging Photopolarimeter (IPP) at sun-spacecraft distances from 1 to 3 AU have been analyzed to derive the brightness of the zodiacal light near the ecliptic at elongations greater than 90 degrees. The change in zodiacal light brightness with heliocentric distance is compared with models of the spatial distribution of the dust. Use of background starlight brightnesses derived from IPP measurements beyond the asteroid belt, where the zodiacal light is not detected, and, especially, use of a corrected calibration lead to considerably lower values for zodiacal light than those reported by us previously.

  12. Galactic and zodiacal light surface brightness measurements with the Atmosphere Explorer satellites

    NASA Technical Reports Server (NTRS)

    Abreu, V. J.; Hays, P. B.; Yee, J. H.

    1982-01-01

    Galactic and zodiacal light surface maps based on the Atmosphere Explorer-C, -D, and -E satellite data are presented at 7320, 6300, 5577, 5200, and 4278 A. A procedure used to generate these maps, which involves separation of the individual stars and diffuse starlight from the zodiacal light, is described in detail. The maps can be used in atmospheric emission studies to correct for galactic emissions which contaminate satellite as well as ground-based photometric observations. The zodiacal light maps show enhanced features which are important for understanding the nature of interplanetary dust.

  13. Research studies using OSO-6 zodiacal light experiment data

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The results of research studies on the OSO-6 zodiacal light experiment, conducted during the period from May 1976 to October 1977 are described. A discussion is included of the instrument performance and the empirical calibrations developed. Main areas of the research performed, i.e., (1) zodiacal light variation analysis; (2) integrated starlight and diffuse galactic light; and (3) earth/moon libration region counterglow, are covered. Considerable data processing was performed during these studies and it is summarized. Recommendations for future research to complete the interim results are given.

  14. PROVAT: a tool for Voronoi tessellation analysis of protein structures and complexes.

    PubMed

    Gore, Swanand P; Burke, David F; Blundell, Tom L

    2005-08-01

    Voronoi tessellation has proved to be a useful tool in protein structure analysis. We have developed PROVAT, a versatile public domain software that enables computation and visualization of Voronoi tessellations of proteins and protein complexes. It is a set of Python scripts that integrate freely available specialized software (Qhull, Pymol etc.) into a pipeline. The calculation component of the tool computes Voronoi tessellation of a given protein system in a way described by a user-supplied XML recipe and stores resulting neighbourhood information as text files with various styles. The Python pickle file generated in the process is used by the visualization component, a Pymol plug-in, that offers a GUI to explore the tessellation visually. PROVAT source code can be downloaded from http://raven.bioc.cam.ac.uk/~swanand/Provat1, which also provides a webserver for its calculation component, documentation and examples.

  15. Teeth and numerology from zodiac signs. A correlative study.

    PubMed

    Kudva, S; Bhat, A P

    2000-01-01

    Comparative anatomical descriptions have been time and again mentioned in the literature. Based on these aspects, an attempt is made to correlate the morphological features of the human teeth, the zodiac sun signs and numerology. This unique study (first ever of its kind) is also done with a purpose as to whether a particular 'Zodiac Sunsign' or numerology can predict about an individual dental health, the same way the future predictions are being made. It was quite interesting to note that there are few definite attributable dental morphological traits and health to the specific sun signs and numerology.

  16. The influence of the Chinese zodiac on fertility in Hong Kong SAR.

    PubMed

    Yip, Paul S F; Lee, Joseph; Cheung, Y B

    2002-11-01

    The annual total of births in Hong Kong SAR fell substantially in the past 20 years; hence the total fertility rate (TFR) followed the downward trend and dropped to a low of 0.9 below replacement level in 2000. Despite the long-term downward trend, short-run increases in the annual total of births and the TFR were exhibited. Such temporary fertility increases are identified in the Dragon Years of 1988 and 2000. The phenomenon of fertility changes associated with zodiacal animal years is examined in this paper with a view to gaining some insight into whether Chinese cultural preferences and folklore beliefs might have influenced prospective parents' reproductive behaviour. The paper explains the underlying philosophy of the Chinese astrological tradition and discusses how zodiacal preferences affect fertility between 1976 and 2000. The paper also explores why zodiacal influences on Chinese fertility before 1976 did not exist. It is unquestionable that the Dragon Year preference exerts an influence on fertility of modern Chinese populations through zodiacal birth-timing motivations. Birth rate rise in the Dragon Year is due to changes in timing of births that will have little effect on cumulative fertility.

  17. A study of extended zodiacal structures

    NASA Technical Reports Server (NTRS)

    Sykes, Mark V.

    1990-01-01

    Observations of cometary dust trails and zodiacal dust bands, discovered by the Infrared Astronomical Satellite (IRAS) were analyzed in a continuing effort to understand their nature and relationship to comets, asteroids, and processes effecting those bodies. A survey of all trails observed by IRAS has been completed, and analysis of this phenomenon continues. A total of 8 trails have been associated with known short-period comets (Churyumov-Gerasimenko, Encke, Gunn, Kopff, Pons-Winnecke, Schwassmann-Wachmann 1, Tempel 1, and Tempel 2), and a few faint trails have been detected which are not associated with any known comet. It is inferred that all short-period comets may have trails, and that the trails detected were seen as a consequence of observational selection effects. Were IRAS launched today, it would likely observe a largely different set of trails. The Tempel 2 trail exhibits a small but significant excess in color temperature relative to a blackbody at the same heliocentric distance. This excess may be due to the presence of a population of small, low-beta particles deriving from large particles within the trail, or a temperature gradient over the surface of large trail particles. Trails represent the very first stage in the formation and evolution of a meteor stream, and may also be the primary mechanism by which comets contribute to the interplanetary dust complex. A mathematical model of the spatial distribution of orbitally evolved collisional debris was developed which reproduces the zodiacal dust band phenomena and was used in the analysis of dust band observations made by IRAS. This has resulted in the principal zodiacal dust bands being firmly related to the principal Hirayama asteroid families. In addition, evidence for the collisional diffusion of the orbital elements of the dust particles has been found in the case of dust generated in the Eos asteroid family.

  18. Experiment S001: Zodiacal Light Photography

    NASA Technical Reports Server (NTRS)

    Ney, E. P.; Huch, W. F.

    1971-01-01

    Observations made during the Gemini 5, 9, and 10 missions in the context of their relation to ground-based and balloon-based experiments on dim-light phenomena are reported. Zodiacal light is the visible manifestation of dust grains in orbit around the sun. The negatives that were exposed on the Gemini 9 mission were studied by the use of an isodensitracer to produce intensity isophotes. Data on the following factors were obtained: (1) intensity distribution of the zodiacal light, both morning and evening; (2) the height and intensity of the airglow at various geographic positions; and (3) intensity distribution of the Milky Way in the region of the sky near Cygnus. Also, a previously unreported phenomenon was discovered. This phenomenon appeared as an upward extension of the normal 90-kilometer airglow layer. The extension was in the form of wisps or plumes approximately 5 deg wide and extending upward approximately 5 deg. The results obtained from pictures exposed on the Gemini 10 mission were of qualitative or geometrical value only.

  19. Skylab experiment SO73: Gegenschein/zodiacal light. [electrophotometry of surface brightness and polarization

    NASA Technical Reports Server (NTRS)

    Weinberg, J. L.

    1976-01-01

    A 10 color photoelectric polarimeter was used to measure the surface brightness and polarization associated with zodiacal light, background starlight, and spacecraft corona during each of the Skylab missions. Fixed position and sky scanning observations were obtained during Skylab missions SL-2 and SL-3 at 10 wavelenghts between 4000A and 8200A. Initial results from the fixed-position data are presented on the spacecraft corona and on the polarized brightness of the zodiacal light. Included among the fixed position regions that were observed are the north celestial pole, south ecliptic pole, two regions near the north galactic pole, and 90 deg from the sun in the ecliptic. The polarized brightness of the zodiacal light was found to have the color of the sun at each of these positions. Because previous observations found the total brightness to have the color of the sun from the near ultraviolet out to 2.4 micrometers, the degree of polarization of the zodiacal light is independent of wavelength from 4000A to 8200A.

  20. Identifying phase-space boundaries with Voronoi tessellations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Debnath, Dipsikha; Gainer, James S.; Kilic, Can

    Determining the masses of new physics particles appearing in decay chains is an important and longstanding problem in high energy phenomenology. Recently it has been shown that these mass measurements can be improved by utilizing the boundary of the allowed region in the fully differentiable phase space in its full dimensionality. Here in this paper we show that the practical challenge of identifying this boundary can be solved using techniques based on the geometric properties of the cells resulting from Voronoi tessellations of the relevant data. The robust detection of such phase-space boundaries in the data could also be usedmore » to corroborate a new physics discovery based on a cut-and-count analysis.« less

  1. Identifying phase-space boundaries with Voronoi tessellations

    DOE PAGES

    Debnath, Dipsikha; Gainer, James S.; Kilic, Can; ...

    2016-11-24

    Determining the masses of new physics particles appearing in decay chains is an important and longstanding problem in high energy phenomenology. Recently it has been shown that these mass measurements can be improved by utilizing the boundary of the allowed region in the fully differentiable phase space in its full dimensionality. Here in this paper we show that the practical challenge of identifying this boundary can be solved using techniques based on the geometric properties of the cells resulting from Voronoi tessellations of the relevant data. The robust detection of such phase-space boundaries in the data could also be usedmore » to corroborate a new physics discovery based on a cut-and-count analysis.« less

  2. A Global, Multi-Waveband Model for the Zodiacal Cloud

    NASA Technical Reports Server (NTRS)

    Grogan, Keith; Dermott, Stanley F.; Kehoe, Thomas J. J.

    2003-01-01

    This recently completed three-year project was undertaken by the PI at the University of Florida, NASA Goddard and JPL, and by the Co-I and Collaborator at the University of Florida. The funding was used to support a continuation of research conducted at the University of Florida over the last decade which focuses on the dynamics of dust particles in the interplanetary environment. The main objectives of this proposal were: To produce improved dynamical models of the zodiacal cloud by performing numerical simulations of the orbital evolution of asteroidal and cometary dust particles. To provide visualizations of the results using our visualization software package, SIMUL, simulating the viewing geometries of IRAS and COBE and comparing the model results with archived data. To use the results to provide a more accurate model of the brightness distribution of the zodiacal cloud than existing empirical models. In addition, our dynamical approach can provide insight into fundamental properties of the cloud, including but not limited to the total mass and surface area of dust, the size-frequency distribution of dust, and the relative contributions of asteroidal and cometary material. The model can also be used to provide constraints on trace signals from other sources, such as dust associated with the "Plutinos" , objects captured in the 2:3 resonance with Neptune.

  3. Sources of zodiacal dust particles

    NASA Astrophysics Data System (ADS)

    Ipatov, S. I.; Mather, J. C.

    2007-08-01

    The orbital evolution of dust particles produced by asteroids, comets, and trans- Neptunian objects was integrated [1-3]. Analysis of results of these integrations testify in favor of a considerable fraction of particles produced by comets among overall zodiacal dust particles, but it does not contradict to >30% of asteroidal dust needed for explanation of formation of dust bands. Fractions of asteroidal particles, particles originating beyond Jupiter's orbit (including trans-Neptunian particles), and cometary particles originating inside of Jupiter's orbit are estimated to be about 1/3 each, with a possible deviation from 1/3 up to 0.1-0.2. Comparison of the plots of the number density vs. the distance R from the Sun obtained for particles produced by different small bodies with the plots based on observations shows that asteroidal and trans- Neptunian particles alone can not explain the observed almost constant number density at R ∼3-18 AU and a lot of particles must be produced by comets at R ∼5-10 AU [2-3]. Comparison of the WHAM (Wisconsin H-Alpha Mapper spectrometer) observations of spectra of zodiacal light with our models showed [4-5] that a significant fraction of particles produced by short-period comets is required to fit the observations of the width and velocity of the Mg I line. Comparison of the observations of the number density inside Jupiter's orbit with the number density of particles produced by different small bodies leads to the same conclusion about a considerable fraction of cometary particles. This comparison does not make limitations on cometary particles produced beyond Jupiter's orbit, but it shows that the fraction of particles produced by Encke-type comets (with eccentricities ∼0.8-0.9) does not exceed 0.15 of the overall population. The estimated fraction of particles produced by long-period and Halley-type comets among zodiacal dust also does not exceed 0.1-0.15. Though trans-Neptunian particles fit different observations of

  4. The Zodiacal Emission Spectrum as Determined by COBE and its Implications

    NASA Technical Reports Server (NTRS)

    Fixsen, D. J.; Dwek, Eli; Oliversen, R. (Technical Monitor)

    2002-01-01

    We combine observations from the DIRBE and FIRAS instruments on the COBE satellite to derive an annually-averaged spectrum of the zodiacal cloud in the 10 to 1000 micron wavelength region. The spectrum exhibits a break at approx. 150 microns which indicates a sharp break in the dust size distribution at a radius of about 30 microns The spectrum can be fit with a single blackbody with a lambda(exp -2) emissivity law beyond 150 microns and a temperature of 240 K. We also used a more realistic characterization of the cloud to fit the spectrum, including a distribution of dust temperatures, representing different dust compositions and distances from the sun, as well as a realistic representation of the spatial distribution of the dust. We show that amorphous carbon and silicate dust with respective temperatures of 280 and 274 K at 1 AU, and size distributions with a break at grain radii of 14 and 32 microns, can provide a good fit to the average zodiacal dust spectrum. The total mass of the zodiacal cloud is 2 to 11 Eg (Eg=10(exp 18) g), depending on the grain composition. The lifetime of the cloud, against particle loss by Poynting- Robertson drag and the effects of solar wind, is about 10(exp 5) yr. The required replenishment rate is approx. 10(exp 14) g/yr. If this is provided by asteroid belt alone, the asteroids lifetime would be approx. 3 x 10(exp 10) yr. But comets and Kuiper belt objects may also contribute to the zodiacal cloud.

  5. The Primeval Zodiac: Its Social, Religious, and Mythological Background

    NASA Astrophysics Data System (ADS)

    Verderame, L.

    2009-08-01

    In this brief paper we try to draw the lines of the possible development of the originary iconographic and symbolic repertoire of the Mesopotamian zodiac, which through the Greeks was adopted in the Western world.

  6. Ten-color Gegenschein-zodiacal light photometer. [onboard Skylab

    NASA Technical Reports Server (NTRS)

    Sparrow, J. G.; Weinberg, J. L.; Hahn, R. C.

    1977-01-01

    A ten-color Fabry photometer was used during Skylab missions SL-2 and SL-3 to measure sky brightness and polarization associated with zodiacal light, background starlight, F region airglow, and spacecraft corona. A brief description is given of the design, calibration, and performance of the instrument.

  7. 72. 451 MADISON AVENUE, GRAND STAIR, ZODIAC CLOCK WITH DECORATIVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    72. 451 MADISON AVENUE, GRAND STAIR, ZODIAC CLOCK WITH DECORATIVE CARVING BY STANFORD WHITE AND AUGUSTUS SAINT-GAUDENS - Villard Houses, 451-457 Madison Avenue & 24 East Fifty-first Street, New York County, NY

  8. Efficient Delaunay Tessellation through K-D Tree Decomposition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Morozov, Dmitriy; Peterka, Tom

    Delaunay tessellations are fundamental data structures in computational geometry. They are important in data analysis, where they can represent the geometry of a point set or approximate its density. The algorithms for computing these tessellations at scale perform poorly when the input data is unbalanced. We investigate the use of k-d trees to evenly distribute points among processes and compare two strategies for picking split points between domain regions. Because resulting point distributions no longer satisfy the assumptions of existing parallel Delaunay algorithms, we develop a new parallel algorithm that adapts to its input and prove its correctness. We evaluatemore » the new algorithm using two late-stage cosmology datasets. The new running times are up to 50 times faster using k-d tree compared with regular grid decomposition. Moreover, in the unbalanced data sets, decomposing the domain into a k-d tree is up to five times faster than decomposing it into a regular grid.« less

  9. Ontogeny, morphology and mechanics of the tessellated skeleton of cartilaginous fishes

    NASA Astrophysics Data System (ADS)

    Dean, Mason N.

    2009-12-01

    The members of the successful and diverse lineage of elasmobranch fishes (sharks, rays and relatives) possess endoskeletons fashioned entirely of cartilage. This is counterintuitive because cartilage, unlike bone, lacks a major blood supply and has limited capacity for repair; yet these fishes exhibit particularly dynamic lifestyles and high levels of performance. The functionality of this skeletal tissue is likely due to its mineralization: in most skeletal elements, the soft cartilage core is tiled (tessellated) with an outer rind of abutting hydroxyapatite blocks called tesserae, joined together by intertesseral fibers and overlain by the fibrous perichondrium. This basic composite arrangement of tissues has been appreciated for over a century, but available techniques have limited the ability to examine elasmobranch cartilage adequately---without artifacts, in 3-dimensions and at high resolution---so that its development, mechanics and phylogeny might be contextualized among vertebrate skeletal tissues. I summarize the history, nomenclature and challenges relating to study of tessellated cartilage (Chapter 1) and present a low temperature microscopy technique to facilitate visualization of all tissue components in situ (Chapter 2). I use that technique in tandem with synchrotron microtomography to examine the ultrastructure of tesserae (Chapter 3) and the development of tessellated cartilage across ontogeny (Chapter 4). Finally, I examine the ways in which selection acts on skeletal morphology by examining cranial anatomy across 40 species of batoid fishes (rays and relatives) in the contexts of ecology and phylogeny (Chapter 5). There are some similarities between mineralizing bone and elasmobranch cartilage (e.g. the flattening of peripheral cells in the unmineralized phase, decreases in cellular density with mineralization, the presence of canaliculi connecting entombed cells). However, the ability for tessellated cartilage to grow (through enlargement of

  10. Is the zodiacal light intensity steady. [cloud surface brightness and polarization from OSO-5 data

    NASA Technical Reports Server (NTRS)

    Burnett, G. B.; Sparrow, J. G.; Ney, E. P.

    1974-01-01

    It is pointed out that conclusions reported by Sparrow and Ney (1972, 1973) could be confirmed in an investigation involving the refinement of OSO-5 data on zodiacal light. It had been found by Sparrow and Ney that the absolute value of both the surface brightness and polarization of the zodiacal cloud varied by less than 10% over the 4-yr period from January 1969 to January 1973.

  11. Three-Dimensional Random Voronoi Tessellations: From Cubic Crystal Lattices to Poisson Point Processes

    NASA Astrophysics Data System (ADS)

    Lucarini, Valerio

    2009-01-01

    We perturb the simple cubic (SC), body-centered cubic (BCC), and face-centered cubic (FCC) structures with a spatial Gaussian noise whose adimensional strength is controlled by the parameter α and analyze the statistical properties of the cells of the resulting Voronoi tessellations using an ensemble approach. We concentrate on topological properties of the cells, such as the number of faces, and on metric properties of the cells, such as the area, volume and the isoperimetric quotient. The topological properties of the Voronoi tessellations of the SC and FCC crystals are unstable with respect to the introduction of noise, because the corresponding polyhedra are geometrically degenerate, whereas the tessellation of the BCC crystal is topologically stable even against noise of small but finite intensity. Whereas the average volume of the cells is the intensity parameter of the system and does not depend on the noise, the average area of the cells has a rather interesting behavior with respect to noise intensity. For weak noise, the mean area of the Voronoi tessellations corresponding to perturbed BCC and FCC perturbed increases quadratically with the noise intensity. In the case of perturbed SCC crystals, there is an optimal amount of noise that minimizes the mean area of the cells. Already for a moderate amount of noise ( α>0.5), the statistical properties of the three perturbed tessellations are indistinguishable, and for intense noise ( α>2), results converge to those of the Poisson-Voronoi tessellation. Notably, 2-parameter gamma distributions constitute an excellent model for the empirical pdf of all considered topological and metric properties. By analyzing jointly the statistical properties of the area and of the volume of the cells, we discover that also the cells shape, measured by the isoperimetric quotient, fluctuates. The Voronoi tessellations of the BCC and of the FCC structures result to be local maxima for the isoperimetric quotient among space

  12. Signatures of planets: Observations and modeling of structure in the zodiacal cloud and Kuiper disk

    NASA Astrophysics Data System (ADS)

    Holmes, Elizabeth Katherine

    2002-12-01

    There is a possible connection between structure in evolved circumstellar disks and the presence of planets, our own zodiacal cloud being a proven example. Asymmetries in such a disk could be diagnostic of planets which would be otherwise undetectable. Using COBE DIRBE observations, we link structure in the zodiacal cloud, namely the warp and offset of the cloud, to the presence of planets using secular perturbation theory. In addition, we obtain supplementary ISO observations and determine a scale factor for the data which we apply to calibrate the data to the observed COBE brightness. A Kuiper dust disk will have a resonant structure, with two concentrations in brightness along the ecliptic longitude arising because 10 15% of the Kuiper belt objects are in the 3:2 mean motion resonance with Neptune. We run numerical integrations of particles originating from source bodies trapped in the 3:2 resonance and we determine what percentage of particles remain in the resonance for a variety of particle and source body sizes. The dynamical evolution of the particles is followed from source to sink with Poynting- Robertson light drag, solar wind drag, radiation pressure, the Lorentz force, neutral interstellar gas drag, and the effects of planetary gravitational perturbations included. We then conduct an observational search in the 60 μm COBE data for the Kuiper disk, which is predicted to be, at most, a few percent of the brightness of the zodiacal cloud. By removing emission due to the background zodiacal cloud and the dust bands, we expect to see the trailing/leading signature of Earth's resonant ring. However, when subtracted from the data, we find that none of the empirical background zodiacal cloud models give the residuals predicted by theory. We conclude that a dynamical two-component (both inner and outer) zodiacal cloud model must be created to complete the search. Lastly, we extend our work outside the solar system and obtain upper limits on the flux around ten

  13. The Chevroches zodiacal cap and its Burgundy relations

    NASA Astrophysics Data System (ADS)

    Devevey, Frédéric; Vernou, Christian; Rousseau, Aurélie

    2011-06-01

    The excavation of an unexplored secondary agglomeration in Chevroches (France), from 2001 to 2002 has led to the discovery of a bronze dome of a type unknown in the Ancient world. It is inscribed with three lines in Greek transcribing Egyptian and Roman months, and the twelve signs of the Zodiac. This paper presents the first observations and some other finds from similar objects in Burgundy.

  14. Boundaries, kinetic properties, and final domain structure of plane discrete uniform Poisson-Voronoi tessellations with von Neumann neighborhoods.

    PubMed

    Korobov, A

    2009-03-01

    Discrete random tessellations appear not infrequently in describing nucleation and growth transformations. Generally, several non-Euclidean metrics are possible in this case. Previously [A. Korobov, Phys. Rev. B 76, 085430 (2007)] continual analogs of such tessellations have been studied. Here one of the simplest discrete varieties of the Kolmogorov-Johnson-Mehl-Avrami model, namely, the model with von Neumann neighborhoods, has been examined per se, i.e., without continualization. The tessellation is uniform in the sense that domain boundaries consist of tiles. Similarities and distinctions between discrete and continual models are discussed.

  15. Curvature, metric and parametrization of origami tessellations: theory and application to the eggbox pattern.

    PubMed

    Nassar, H; Lebée, A; Monasse, L

    2017-01-01

    Origami tessellations are particular textured morphing shell structures. Their unique folding and unfolding mechanisms on a local scale aggregate and bring on large changes in shape, curvature and elongation on a global scale. The existence of these global deformation modes allows for origami tessellations to fit non-trivial surfaces thus inspiring applications across a wide range of domains including structural engineering, architectural design and aerospace engineering. The present paper suggests a homogenization-type two-scale asymptotic method which, combined with standard tools from differential geometry of surfaces, yields a macroscopic continuous characterization of the global deformation modes of origami tessellations and other similar periodic pin-jointed trusses. The outcome of the method is a set of nonlinear differential equations governing the parametrization, metric and curvature of surfaces that the initially discrete structure can fit. The theory is presented through a case study of a fairly generic example: the eggbox pattern. The proposed continuous model predicts correctly the existence of various fittings that are subsequently constructed and illustrated.

  16. Curvature, metric and parametrization of origami tessellations: theory and application to the eggbox pattern

    NASA Astrophysics Data System (ADS)

    Nassar, H.; Lebée, A.; Monasse, L.

    2017-01-01

    Origami tessellations are particular textured morphing shell structures. Their unique folding and unfolding mechanisms on a local scale aggregate and bring on large changes in shape, curvature and elongation on a global scale. The existence of these global deformation modes allows for origami tessellations to fit non-trivial surfaces thus inspiring applications across a wide range of domains including structural engineering, architectural design and aerospace engineering. The present paper suggests a homogenization-type two-scale asymptotic method which, combined with standard tools from differential geometry of surfaces, yields a macroscopic continuous characterization of the global deformation modes of origami tessellations and other similar periodic pin-jointed trusses. The outcome of the method is a set of nonlinear differential equations governing the parametrization, metric and curvature of surfaces that the initially discrete structure can fit. The theory is presented through a case study of a fairly generic example: the eggbox pattern. The proposed continuous model predicts correctly the existence of various fittings that are subsequently constructed and illustrated.

  17. Voronoi Tessellation for reducing the processing time of correlation functions

    NASA Astrophysics Data System (ADS)

    Cárdenas-Montes, Miguel; Sevilla-Noarbe, Ignacio

    2018-01-01

    The increase of data volume in Cosmology is motivating the search of new solutions for solving the difficulties associated with the large processing time and precision of calculations. This is specially true in the case of several relevant statistics of the galaxy distribution of the Large Scale Structure of the Universe, namely the two and three point angular correlation functions. For these, the processing time has critically grown with the increase of the size of the data sample. Beyond parallel implementations to overcome the barrier of processing time, space partitioning algorithms are necessary to reduce the computational load. These can delimit the elements involved in the correlation function estimation to those that can potentially contribute to the final result. In this work, Voronoi Tessellation is used to reduce the processing time of the two-point and three-point angular correlation functions. The results of this proof-of-concept show a significant reduction of the processing time when preprocessing the galaxy positions with Voronoi Tessellation.

  18. Voronoi-Tessellated Graphite Produced by Low-Temperature Catalytic Graphitization from Renewable Resources.

    PubMed

    Zhao, Leyi; Zhao, Xiuyun; Burke, Luke T; Bennett, J Craig; Dunlap, Richard A; Obrovac, Mark N

    2017-09-11

    A highly crystalline graphite powder was prepared from the low temperature (800-1000 °C) graphitization of renewable hard carbon precursors using a magnesium catalyst. The resulting graphite particles are composed of Voronoi-tessellated regions comprising irregular sheets; each Voronoi-tessellated region having a small "seed" particle located near their centroid on the surface. This suggests nucleated outward growth of graphitic carbon, which has not been previously observed. Each seed particle consists of a spheroidal graphite shell on the inside of which hexagonal graphite platelets are perpendicularly affixed. This results in a unique high surface area graphite with a high degree of graphitization that is made with renewable feedstocks at temperatures far below that conventionally used for artificial graphites. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Rutgers zodiacal light experiment on OSO-6

    NASA Technical Reports Server (NTRS)

    Carroll, B.

    1975-01-01

    A detector was placed in a slowly spinning wheel on OSO-6 whose axis was perpendicular to the line drawn to the sun, to measure the surface brightness and polarization at all elongations from the immediate neighborhood of the sun to the anti-solar point. Different wavelength settings and polarizations were calculated from the known order of magnitude brightness of the zodiacal light. The measuring sequence was arranged to give longer integration times for the regions of lower surface brightness. Three types of analysis to which the data on OSO-6 were subjected are outlined; (1) photometry, (2) colorimetry and (3) polarimetry.

  20. Polarization of the zodiacal light - First results from Skylab

    NASA Technical Reports Server (NTRS)

    Sparrow, J. G.; Weinberg, J. L.; Hahn, R. C.

    1976-01-01

    A brief description is given of the Skylab ten color photoelectric photometer and the programs of measurements made during Skylab missions SL-2 and SL-3. Results obtained on the polarized brightness of zodiacal light at five points on the antisolar hemisphere are discussed and compared with other published data for the north celestial pole, south ecliptic pole, at elongation 90 degrees on the ecliptic, and at two places near the north galactic pole.

  1. Detecting Corresponding Vertex Pairs between Planar Tessellation Datasets with Agglomerative Hierarchical Cell-Set Matching.

    PubMed

    Huh, Yong; Yu, Kiyun; Park, Woojin

    2016-01-01

    This paper proposes a method to detect corresponding vertex pairs between planar tessellation datasets. Applying an agglomerative hierarchical co-clustering, the method finds geometrically corresponding cell-set pairs from which corresponding vertex pairs are detected. Then, the map transformation is performed with the vertex pairs. Since these pairs are independently detected for each corresponding cell-set pairs, the method presents improved matching performance regardless of locally uneven positional discrepancies between dataset. The proposed method was applied to complicated synthetic cell datasets assumed as a cadastral map and a topographical map, and showed an improved result with the F-measures of 0.84 comparing to a previous matching method with the F-measure of 0.48.

  2. ColDICE: A parallel Vlasov–Poisson solver using moving adaptive simplicial tessellation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sousbie, Thierry, E-mail: tsousbie@gmail.com; Department of Physics, The University of Tokyo, Tokyo 113-0033; Research Center for the Early Universe, School of Science, The University of Tokyo, Tokyo 113-0033

    2016-09-15

    Resolving numerically Vlasov–Poisson equations for initially cold systems can be reduced to following the evolution of a three-dimensional sheet evolving in six-dimensional phase-space. We describe a public parallel numerical algorithm consisting in representing the phase-space sheet with a conforming, self-adaptive simplicial tessellation of which the vertices follow the Lagrangian equations of motion. The algorithm is implemented both in six- and four-dimensional phase-space. Refinement of the tessellation mesh is performed using the bisection method and a local representation of the phase-space sheet at second order relying on additional tracers created when needed at runtime. In order to preserve in the bestmore » way the Hamiltonian nature of the system, refinement is anisotropic and constrained by measurements of local Poincaré invariants. Resolution of Poisson equation is performed using the fast Fourier method on a regular rectangular grid, similarly to particle in cells codes. To compute the density projected onto this grid, the intersection of the tessellation and the grid is calculated using the method of Franklin and Kankanhalli [65–67] generalised to linear order. As preliminary tests of the code, we study in four dimensional phase-space the evolution of an initially small patch in a chaotic potential and the cosmological collapse of a fluctuation composed of two sinusoidal waves. We also perform a “warm” dark matter simulation in six-dimensional phase-space that we use to check the parallel scaling of the code.« less

  3. Canaliculi in the tessellated skeleton of cartilaginous fishes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dean, M.N.; Socha, J.J.; Hall, B.K.

    2010-08-04

    The endoskeletal elements of sharks and rays are comprised of an uncalcified, hyaline cartilage-like core overlain by a thin fibro-ceramic layer of mineralized hexagonal tiles (tesserae) adjoined by intertesseral fibers. The basic spatial relationships of the constituent tissues (unmineralized cartilage, mineralized cartilage, fibrous tissue) are well-known - endoskeletal tessellation is a long-recognized synapomorphy of elasmobranch fishes - but a high-resolution and three-dimensional (3D) understanding of their interactions has been hampered by difficulties in sample preparation and lack of technologies adequate for visualizing microstructure and microassociations. We used cryo-electron microscopy and synchrotron radiation tomography to investigate tessellated skeleton ultrastructure but withoutmore » damage to the delicate relationships between constituent tissues or to the tesserae themselves. The combination of these techniques allowed visualization of never before appreciated internal structures, namely passages connecting the lacunar spaces within tesserae. These intratesseral 'canaliculi' link consecutive lacunar spaces into long lacunar strings, radiating outward from the center of tesserae. The continuity of extracellular matrix throughout the canalicular network may explain how chondrocytes in tesserae remain vital despite encasement in mineral. Extracellular fluid exchange may also permit transmission of nutrients, and mechanical and mineralization signals among chondrocytes, in a manner similar to the canalicular network in bone. These co-adapted mechanisms for the facilitated exchange of extracellular material suggest a level of parallelism in early chondrocyte and osteocyte evolution.« less

  4. Averaged ratio between complementary profiles for evaluating shape distortions of map projections and spherical hierarchical tessellations

    NASA Astrophysics Data System (ADS)

    Yan, Jin; Song, Xiao; Gong, Guanghong

    2016-02-01

    We describe a metric named averaged ratio between complementary profiles to represent the distortion of map projections, and the shape regularity of spherical cells derived from map projections or non-map-projection methods. The properties and statistical characteristics of our metric are investigated. Our metric (1) is a variable of numerical equivalence to both scale component and angular deformation component of Tissot indicatrix, and avoids the invalidation when using Tissot indicatrix and derived differential calculus for evaluating non-map-projection based tessellations where mathematical formulae do not exist (e.g., direct spherical subdivisions), (2) exhibits simplicity (neither differential nor integral calculus) and uniformity in the form of calculations, (3) requires low computational cost, while maintaining high correlation with the results of differential calculus, (4) is a quasi-invariant under rotations, and (5) reflects the distortions of map projections, distortion of spherical cells, and the associated distortions of texels. As an indicator of quantitative evaluation, we investigated typical spherical tessellation methods, some variants of tessellation methods, and map projections. The tessellation methods we evaluated are based on map projections or direct spherical subdivisions. The evaluation involves commonly used Platonic polyhedrons, Catalan polyhedrons, etc. Quantitative analyses based on our metric of shape regularity and an essential metric of area uniformity implied that (1) Uniform Spherical Grids and its variant show good qualities in both area uniformity and shape regularity, and (2) Crusta, Unicube map, and a variant of Unicube map exhibit fairly acceptable degrees of area uniformity and shape regularity.

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  6. High-Performance Computation of Distributed-Memory Parallel 3D Voronoi and Delaunay Tessellation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Peterka, Tom; Morozov, Dmitriy; Phillips, Carolyn

    2014-11-14

    Computing a Voronoi or Delaunay tessellation from a set of points is a core part of the analysis of many simulated and measured datasets: N-body simulations, molecular dynamics codes, and LIDAR point clouds are just a few examples. Such computational geometry methods are common in data analysis and visualization; but as the scale of simulations and observations surpasses billions of particles, the existing serial and shared-memory algorithms no longer suffice. A distributed-memory scalable parallel algorithm is the only feasible approach. The primary contribution of this paper is a new parallel Delaunay and Voronoi tessellation algorithm that automatically determines which neighbormore » points need to be exchanged among the subdomains of a spatial decomposition. Other contributions include periodic and wall boundary conditions, comparison of our method using two popular serial libraries, and application to numerous science datasets.« less

  7. Properties of plane discrete Poisson-Voronoi tessellations on triangular tiling formed by the Kolmogorov-Johnson-Mehl-Avrami growth of triangular islands

    NASA Astrophysics Data System (ADS)

    Korobov, A.

    2011-08-01

    Discrete uniform Poisson-Voronoi tessellations of two-dimensional triangular tilings resulting from the Kolmogorov-Johnson-Mehl-Avrami (KJMA) growth of triangular islands have been studied. This shape of tiles and islands, rarely considered in the field of random tessellations, is prompted by the birth-growth process of Ir(210) faceting. The growth mode determines a triangular metric different from the Euclidean metric. Kinetic characteristics of tessellations appear to be metric sensitive, in contrast to area distributions. The latter have been studied for the variant of nuclei growth to the first impingement in addition to the conventional case of complete growth. Kiang conjecture works in both cases. The averaged number of neighbors is six for all studied densities of random tessellations, but neighbors appear to be mainly different in triangular and Euclidean metrics. Also, the applicability of the obtained results for simulating birth-growth processes when the 2D nucleation and impingements are combined with the 3D growth in the particular case of similar shape and the same orientation of growing nuclei is briefly discussed.

  8. Properties of plane discrete Poisson-Voronoi tessellations on triangular tiling formed by the Kolmogorov-Johnson-Mehl-Avrami growth of triangular islands.

    PubMed

    Korobov, A

    2011-08-01

    Discrete uniform Poisson-Voronoi tessellations of two-dimensional triangular tilings resulting from the Kolmogorov-Johnson-Mehl-Avrami (KJMA) growth of triangular islands have been studied. This shape of tiles and islands, rarely considered in the field of random tessellations, is prompted by the birth-growth process of Ir(210) faceting. The growth mode determines a triangular metric different from the Euclidean metric. Kinetic characteristics of tessellations appear to be metric sensitive, in contrast to area distributions. The latter have been studied for the variant of nuclei growth to the first impingement in addition to the conventional case of complete growth. Kiang conjecture works in both cases. The averaged number of neighbors is six for all studied densities of random tessellations, but neighbors appear to be mainly different in triangular and Euclidean metrics. Also, the applicability of the obtained results for simulating birth-growth processes when the 2D nucleation and impingements are combined with the 3D growth in the particular case of similar shape and the same orientation of growing nuclei is briefly discussed.

  9. Adaptive acoustic energy delivery to near and far fields using foldable, tessellated star transducers

    NASA Astrophysics Data System (ADS)

    Zou, Chengzhe; Harne, Ryan L.

    2017-05-01

    Methods of guiding acoustic energy arbitrarily through space have long relied on digital controls to meet performance needs. Yet, more recent attention to adaptive structures with unique spatial configurations has motivated mechanical signal processing (MSP) concepts that may not be subjected to the same functional and performance limitations as digital acoustic beamforming counterparts. The periodicity of repeatable structural reconfiguration enabled by origami-inspired tessellated architectures turns attention to foldable platforms as frameworks for MSP development. This research harnesses principles of MSP to study a tessellated, star-shaped acoustic transducer constituent that provides on-demand control of acoustic energy guiding via folding-induced shape reconfiguration. An analytical framework is established to probe the roles of mechanical and acoustic geometry on the far field directivity and near field focusing of sound energy. Following validation by experiments and verification by simulations, parametric studies are undertaken to uncover relations between constituent topology and acoustic energy delivery to arbitrary points in the free field. The adaptations enabled by folding of the star-shaped transducer reveal capability for restricting sound energy to angular regions in the far field while also introducing means to modulate sound energy by three orders-of-magnitude to locations near to the transducer surface. In addition, the modeling philosophy devised here provides a valuable approach to solve general sound radiation problems for foldable, tessellated acoustic transducer constituents of arbitrary geometry.

  10. Zodiacal emission. III - Dust near the asteroid belt

    NASA Technical Reports Server (NTRS)

    Reach, William T.

    1992-01-01

    Properties of the zodiacal dust bands are derived from fits to Infrared Astronomical Satellite profiles of the ecliptic. Three observations lead to the conclusion that the dust-band material is spread over a range of heliocentric distances between the asteroid belt and the sun: parallax, color temperature, and wavelength dependence of the band latitudes. The orientations of the midplanes of the bands are found to be typical of asteroids. A model of 'migrating bands', wherein dust is produced near the asteroid belt and spirals into the sun under the influence of Poynting-Robertson drag, is used to explain the range of heliocentric distances of dust-band material.

  11. Colour-dressed hexagon tessellations for correlation functions and non-planar corrections

    NASA Astrophysics Data System (ADS)

    Eden, Burkhard; Jiang, Yunfeng; le Plat, Dennis; Sfondrini, Alessandro

    2018-02-01

    We continue the study of four-point correlation functions by the hexagon tessellation approach initiated in [38] and [39]. We consider planar tree-level correlation functions in N=4 supersymmetric Yang-Mills theory involving two non-protected operators. We find that, in order to reproduce the field theory result, it is necessary to include SU( N) colour factors in the hexagon formalism; moreover, we find that the hexagon approach as it stands is naturally tailored to the single-trace part of correlation functions, and does not account for multi-trace admixtures. We discuss how to compute correlators involving double-trace operators, as well as more general 1 /N effects; in particular we compute the whole next-to-leading order in the large- N expansion of tree-level BMN two-point functions by tessellating a torus with punctures. Finally, we turn to the issue of "wrapping", Lüscher-like corrections. We show that SU( N) colour-dressing reproduces an earlier empirical rule for incorporating single-magnon wrapping, and we provide a direct interpretation of such wrapping processes in terms of N=2 supersymmetric Feynman diagrams.

  12. Popular belief meets surgical reality: impact of lunar phases, Friday the 13th and zodiac signs on emergency operations and intraoperative blood loss.

    PubMed

    Schuld, Jochen; Slotta, Jan E; Schuld, Simone; Kollmar, Otto; Schilling, Martin K; Richter, Sven

    2011-09-01

    The influence of superstition, moon calendars, and popular belief on evidence-based medicine is stunning. More than 40% of medical staff is convinced that lunar phases can affect human behavior. The idea that Friday the 13th is associated with adverse events and bad luck is deep-rooted in the population of Western industrial countries. The aim of the present study was to test the hypothesis that these myths are transferable to real-life surgery. We analyzed the extent to which moon phases, zodiac signs, and Friday the 13th influence blood loss, emergency frequency, and intestinal perforations by evaluating the operation records of all 27,914 consecutive patients of our institution undergoing general, visceral, or vascular surgery between August 2001 and August 2010. Dates of surgery were allocated to lunar phases and to zodiac signs, as well as to Friday the 13th. A total of 111 lunar cycles and 15 Fridays the 13th occurred within the 3,281-day observation period. Patients' characteristics did not differ in lunar phases, zodiac signs, or Fridays the 13th. Full moon phases, the presence of Friday the 13th, and zodiac signs influenced neither intraoperative blood loss nor emergency frequency. No statistical peaks regarding perforated aortic aneurysms and gastrointestinal perforations were found on full moon or Friday the 13th. Scientific analysis of our data does not support the belief that moon phases, zodiac signs, or Friday 13th influence surgical blood loss and emergency frequency. Our data indicate that such beliefs are myths far beyond reality.

  13. The mechanics of tessellations - bioinspired strategies for fracture resistance.

    PubMed

    Fratzl, Peter; Kolednik, Otmar; Fischer, F Dieter; Dean, Mason N

    2016-01-21

    Faced with a comparatively limited palette of minerals and organic polymers as building materials, evolution has arrived repeatedly on structural solutions that rely on clever geometric arrangements to avoid mechanical trade-offs in stiffness, strength and flexibility. In this tutorial review, we highlight the concept of tessellation, a structural motif that involves periodic soft and hard elements arranged in series and that appears in a vast array of invertebrate and vertebrate animal biomaterials. We start from basic mechanics principles on the effects of material heterogeneities in hypothetical structures, to derive common concepts from a diversity of natural examples of one-, two- and three-dimensional tilings/layerings. We show that the tessellation of a hard, continuous surface - its atomization into discrete elements connected by a softer phase - can theoretically result in maximization of material toughness, with little expense to stiffness or strength. Moreover, the arrangement of soft/flexible and hard/stiff elements into particular geometries can permit surprising functions, such as signal filtering or 'stretch and catch' responses, where the constrained flexibility of systems allows a built-in safety mechanism for ensuring that both compressive and tensile loads are managed well. Our analysis unites examples ranging from exoskeletal materials (fish scales, arthropod cuticle, turtle shell) to endoskeletal materials (bone, shark cartilage, sponge spicules) to attachment devices (mussel byssal threads), from both invertebrate and vertebrate animals, while spotlighting success and potential for bio-inspired manmade applications.

  14. Interpreting medium ring canonical conformers by a triangular plane tessellation of the macrocycle

    NASA Astrophysics Data System (ADS)

    Khalili, Pegah; Barnett, Christopher B.; Naidoo, Kevin J.

    2013-05-01

    Cyclic conformational coordinates are essential for the distinction of molecular ring conformers as the use of Cremer-Pople coordinates have illustrated for five- and six-membered rings. Here, by tessellating medium rings into triangular planes and using the relative angles made between triangular planes we are able to assign macrocyclic pucker conformations into canonical pucker conformers such as chairs, boats, etc. We show that the definition is straightforward compared with other methods popularly used for small rings and that it is computationally simple to implement for complex macrocyclic rings. These cyclic conformational coordinates directly couple to the motion of individual nodes of a ring. Therefore, they are useful for correlating the physical properties of macrocycles with their ring pucker and measuring the dynamic ring conformational behavior. We illustrate the triangular tessellation, assignment, and pucker analysis on 7- and 8-membered rings. Sets of canonical states are given for cycloheptane and cyclooctane that have been previously experimentally analysed.

  15. The evolution of the zodiac in the context of ancient oriental history

    NASA Astrophysics Data System (ADS)

    Gurshtein, Alex A.

    The dates for the second (ca. 2700 B.C. to within 250 years) and the third ecliptical quartets (ca. 1200 B.C. to within 400 years) evaluated earlier are considered in the context of ancient Egyptian history. The origin of the second quartet coincides with the Great Pyramids and the initiation of the Egyptian solar, or so-called "civil" calendar, the first of such a type in the world. The third quartet is concurrent with the solar conversion of Amenhotep IV (Akhenaton) and takes place at the finale of the great Sothic period of 1461 years after the initiation of the solar calendar. It is argued that the Great Pyramids seem to be monuments to the Sun-god built in honor of the Egyptians having reached an understanding of the Sun's track upon the starry background, Akhenaton's conversion being in a direct connection with the original Pyramids' ideology. This paper is the third part of a single investigation. The first two parts "On the Origin of the Zodiacal Constellations" and "Prehistory of Zodiac Dating: Three Strata of Upper Paleolithic Constellations" were published in Vistas in Astronomy in 1993 and 1995.

  16. The influence of lunar phases and zodiac sign 'Leo' on perioperative complications and outcome in elective spine surgery.

    PubMed

    Joswig, Holger; Stienen, Martin N; Hock, Carolin; Hildebrandt, Gerhard; Surbeck, Werner

    2016-06-01

    Many people believe that the moon has an influence on daily life, and some even request elective surgery dates depending on the moon calendar. The aim of this study was to assess the influence of 'unfavorable' lunar or zodiac constellations on perioperative complications and outcome in elective surgery for degenerative disc disease. Retrospective database analysis including 924 patients. Using uni- and multivariate logistic regression, the likelihood for intraoperative complications and re-do surgeries as well as the clinical outcomes at 4 weeks was analyzed for surgeries performed during the waxing moon, full moon, and dates when the moon passed through the zodiac sign 'Leo.' In multivariate analysis, patients operated on during the waxing moon were 1.54 times as likely as patients who were operated on during the waning moon to suffer from an intraoperative complication (OR 1.54, 95 % CI 1.07-2.21, p = 0.019). In contrast, there was a trend toward fewer re-do surgeries for surgery during the waxing moon (OR 0.51, 95 % CI 0.23-1.16, p = 0.109), while the 4-week responder status was similar (OR 0.73, 95 % CI 0.47-1.14, p = 0.169). A full moon and the zodiac sign Leo did not increase the likelihood for complications, re-do surgeries or unfavorable outcomes. We found no influence of 'unfavorable' lunar or zodiac constellations on the 4-week responder status or the revision rate that would justify a moon calendar-based selection approach to elective spine surgery dates. However, the fact that patients undergoing surgery during the waxing moon were more likely to suffer from an intraoperative complication is a surprising curiosity and defies our ability to find a rational explanation.

  17. Colour dependence of zodiacal light models

    NASA Technical Reports Server (NTRS)

    Giese, R. H.; Hanner, M. S.; Leinert, C.

    1973-01-01

    Colour models of the zodiacal light in the ecliptic have been calculated for both dielectric and metallic particles in the sub-micron and micron size range. Two colour ratios were computed, a blue ratio and a red ratio. The models with a size distribution proportional to s to the -2.5 power ds (where s is the particle radius) generally show a colour close to the solar colour and almost independent of elongation. Especially in the blue colour ratio there is generally no significant dependence on the lower cutoff size (0.1-1 micron). The main feature of absorbing particles is a reddening at small elongations. The models for size distributions proportional to s to the -4 power ds show larger departures from solar colour and more variation with model parameters. Colour measurements, including red and near infra-red, therefore are useful to distinguish between flat and steep size spectra and to verify the presence of slightly absorbing particles.

  18. The art and science of hyperbolic tessellations.

    PubMed

    Van Dusen, B; Taylor, R P

    2013-04-01

    The visual impact of hyperbolic tessellations has captured artists' imaginations ever since M.C. Escher generated his Circle Limit series in the 1950s. The scaling properties generated by hyperbolic geometry are different to the fractal scaling properties found in nature's scenery. Consequently, prevalent interpretations of Escher's art emphasize the lack of connection with nature's patterns. However, a recent collaboration between the two authors proposed that Escher's motivation for using hyperbolic geometry was as a method to deliberately distort nature's rules. Inspired by this hypothesis, this year's cover artist, Ben Van Dusen, embeds natural fractals such as trees, clouds and lightning into a hyperbolic scaling grid. The resulting interplay of visual structure at multiple size scales suggests that hybridizations of fractal and hyperbolic geometries provide a rich compositional tool for artists.

  19. Prehistory of Zodiac Dating: Three Strata of Upper Paleolithic Constellations

    NASA Astrophysics Data System (ADS)

    Gurshtein, Alex A.

    A pattern of archaic proto-constellations is extracted from Aratus' "The Phaenomena" didactic poem list according to a size criterion elaborated earlier, and their symbolism is analyzed. As a result of this approach three celestial symbolical strata are discovered to be probably a reflection of the symbols for the Lower, the Middle and the Upper Worlds; the Under-World creatures have a water character, the Middle World ones are mostly anthropomorphic and flying beings are for the Upper World. The strata excerpted from Aratus' sky seems to be in agreement with the well-known Babylonian division into three god pathways for Ea (Enki), Anu and Enlil. There is a possibility of dating the pattern discovered because of precession's strong influence as far back as 16 thousand years, the result being supported by the comparison of different star group mean sizes. The archaic constellation pattern under consideration is a reasonable background of symbolical meanings for the first Zodiacal generation quartet (7.5 thousand years old) examined by the author previously. The enormous size of the Argo constellation (Ship of Argo and his Argonauts) as well as the large sizes of other southern constellations are explained as due to the existence of an accumulation zone near the South celestial pole. Some extra correlations between the reconstruction proposed and cultural data available are discussed. The paper is the second part of the investigation "On the Origin of the Zodiacal constellations" published in Vistas in Astronomy, vol.36, pp.171-190, 1993.

  20. Lunar phases and zodiac signs do not influence quality of radical cystectomy--a statistical analysis of 452 patients with invasive bladder cancer.

    PubMed

    May, Matthias; Braun, Kay-Patrick; Helke, Christian; Richter, Willi; Vogler, Horst; Hoschke, Bernd; Siegsmund, Michael

    2007-01-01

    To determine the influence of the lunar phases and the position of the moon in the zodiac on the frequency of complications and the survival of bladder cancer patients after radical cystectomy. It has been postulated that radical cystectomy performed during the waxing moon, or particularly at full moon, or at the zodiac sign Libra is associated with a poorer outcome. We tested this hypothesis by evaluating the progression-free survival, the complication rate and the re-operation rate for 452 consecutive patients after radical cystectomy. In this retrospective review, the dates of surgery were allocated to the lunar phases and the zodiac signs. Based on these classifications, the patients were placed in groups which combined the lunar phase laws and differentiated between evidently unfavorable (full moon or waxing moon and/or the zodiac sign Libra; assigned to group 1) and favorable periods for surgery (new moon or waning moon and other signs of the zodiac apart from Libra; assigned to group 2). The mean follow-up was 49 months (range 0-158 months). A total of 244 patients (54%) were operated during an unfavorable period (group 1) and 208 (46%) patients during the auspicious period (group 2). The mean age, gender and kind of urinary derivation did not differ significantly in the two groups. Pathological tumor stages were evenly distributed according to the lunar phase groups (P = 0.713). We found no significant differences in the perioperative mortality rates, early re-operation rates, early complications, and late complications across the two groups. No significant differences in progression-free survival were observed when timing of cystectomy during the lunar cycle was considered (P = 0.231). Our analysis demonstrated no predictable influence of the lunar phase on survival or complications. Although this was not a prospective randomized trial, the statistical magnitude of the results do not support any recommendations for scheduling patients for radical

  1. The Zodiacal Exoplanets in Time (ZEIT) Survey

    NASA Astrophysics Data System (ADS)

    Mann, Andrew; Gaidos, Eric; Newton, Elisabeth R.; Rizzuto, Aaron C.; Vanderburg, Andrew; Mace, Gregory N.; Kraus, Adam L.

    2017-01-01

    Planets and their host stars evolve with time, and the first few hundred million years are thought to be the most formative. However, the majority of known exoplanets orbit stars older than the timescales of interest (>1 Gyr). We have launched the Zodiacal Exoplanets in Time (ZEIT) survey with the goal of identifying and characterizing young (<1 Gyr) transiting planets. To this end, we have utilized high-precision photometry of nearby young clusters and stellar associations taken as part of the K2 mission. Thus far we have discovered transiting planets in the Hyades and Praesepe clusters (˜800 Myr), and the Upper Scorpius OB association (˜11 Myr), but interestingly none in the Pleiades (˜125 Myr). These discoveries can be used to set limits on the migration timescale, estimate atmosphere loss around young planets, and provide independent tests of pre-main sequence stellar models. Here I overview some key science results from our survey and briefly discuss our plans to identify more young planetary systems.

  2. Quantifying Void Ratio in Granular Materials Using Voronoi Tessellation

    NASA Technical Reports Server (NTRS)

    Alshibli, Khalid A.; El-Saidany, Hany A.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    Voronoi technique was used to calculate the local void ratio distribution of granular materials. It was implemented in an application-oriented image processing and analysis algorithm capable of extracting object edges, separating adjacent particles, obtaining the centroid of each particle, generating Voronoi polygons, and calculating the local void ratio. Details of the algorithm capabilities and features are presented. Verification calculations included performing manual digitization of synthetic images using Oda's method and Voronoi polygon system. The developed algorithm yielded very accurate measurements of the local void ratio distribution. Voronoi tessellation has the advantage, compared to Oda's method, of offering a well-defined polygon generation criterion that can be implemented in an algorithm to automatically calculate local void ratio of particulate materials.

  3. Extra-Zodiacal-Cloud Astronomy via Solar Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Benson, Scott W.; Falck, Robert D.; Oleson, Steven R.; Greenhouse, Matthew A.; Kruk, Jeffrey W.; Gardner, Jonathan P.; Thronson, Harley A.; Vaughn, Frank J.; Fixsen, Dale J.

    2011-01-01

    Solar electric propulsion (SEP) is often considered as primary propulsion for robotic planetary missions, providing the opportunity to deliver more payload mass to difficult, high-delta-velocity destinations. However, SEP application to astrophysics has not been well studied. This research identifies and assesses a new application of SEP as primary propulsion for low-cost high-performance robotic astrophysics missions. The performance of an optical/infrared space observatory in Earth orbit or at the Sun-Earth L2 point (SEL2) is limited by background emission from the Zodiacal dust cloud that has a disk morphology along the ecliptic plane. By delivering an observatory to a inclined heliocentric orbit, most of this background emission can be avoided, resulting in a very substantial increase in science performance. This advantage enabled by SEP allows a small-aperture telescope to rival the performance of much larger telescopes located at SEL2. In this paper, we describe a novel mission architecture in which SEP technology is used to enable unprecedented telescope sensitivity performance per unit collecting area. This extra-zodiacal mission architecture will enable a new class of high-performance, short-development time, Explorer missions whose sensitivity and survey speed can rival flagship-class SEL2 facilities, thus providing new programmatic flexibility for NASA's astronomy mission portfolio. A mission concept study was conducted to evaluate this application of SEP. Trajectory analyses determined that a 700 kg-class science payload could be delivered in just over 2 years to a 2 AU mission orbit inclined 15 to the ecliptic using a 13 kW-class NASA's Evolutionary Xenon Thruster (NEXT) SEP system. A mission architecture trade resulted in a SEP stage architecture, in which the science spacecraft separates from the stage after delivery to the mission orbit. The SEP stage and science spacecraft concepts were defined in collaborative engineering environment studies. The

  4. Clementine Observations of the Zodiacal Light and the Dust Content of the Inner Solar System

    NASA Technical Reports Server (NTRS)

    Hahn, Joseph M.; Zook, Herbert A.; Cooper, Bonnie; Sunkara, Bhaskar

    2002-01-01

    Using the Moon to occult the Sun, the Clementine spacecraft used its navigation cameras to map the inner zodiacal light at optical wavelengths over elongations of 3 approx. less than epsilon approx. less than 30 deg from the Sun. This surface brightness map is then used to infer the spatial distribution of interplanetary dust over heliocentric distances of about 10 solar radii to the orbit of Venus. The averaged ecliptic surface brightness of the zodiacal light falls off as Z(epsilon) is a member of epsilon(sup -2.45 +/- 0.05), which suggests that the dust cross-sectional density nominally falls off as sigma(r) is a member of r(sup - 1.45 +/- 0.05). The interplanetary dust also has an albedo of alpha approx. = 0.1 that is uncertain by a factor of approx. 2. Asymmetries of approx. 10% are seen in directions east-west and north-south of the Sun, and these may be due the giant planets' secular gravitational perturbations. We apply a simple model that attributes the zodiacal light as due to three dust populations having distinct inclination distributions, namely, dust from asteroids and Jupiter-family comets (JFCs) having characteristic inclinations of i approx. 7 deg, dust from Halley-type comets having i approx. 33 deg, and an isotropic cloud of dust from Oort Cloud comets. The best-fitting scenario indicates that asteroids + JFCs are the source of about 45% of the optical dust cross section seen in the ecliptic at 1 AU but that at least 89% of the dust cross section enclosed by a 1-AU-radius sphere is of a cometary origin. Each population's radial density variations can also deviate somewhat from the nominal sigma(r) is a member of r(sup -1.45). When these results are extrapolated out to the asteroid belt, we find an upper limit on the mass of the light-reflecting asteroidal dust that is equivalent to a 12-km asteroid, and a similar extrapolation of the isotropic dust cloud out to Oort Cloud distances yields a mass equivalent to a 30-km comet, although the latter

  5. VizieR Online Data Catalog: XZ Catalog of Zodiacal Stars (XZ80Q) (Herald, 2003)

    NASA Astrophysics Data System (ADS)

    Herald, D.

    2003-11-01

    The XZ catalog was created at the U.S. Naval Observatory in 1977 by Richard Schmidt and Tom Van Flandern, primarily for the purpose of generating predictions of lunar occultations, and for analyzing timings of these events. It was designed to include all stars within 6d 40' of the ecliptic (the "Zodiac"), which is as far as the Moon's limb can ever get as seen from anywhere on the Earth's surface, leaving some margin for stellar proper motions and change in the obliquity of the ecliptic over the course of three centuries. The original version contained 32,221 entries; since that time, many changes have been made in succeeding versions, including better positions and proper motions, and the elimination and addition of stars. Details about the history of XZ catalog can be found in the "doc.txt" file. The XZ80Q revision has been developed from XZ80P, which was created by Mitsuru Soma. It is now complete over the Zodiac for stars down to visual magnitude 12.0. The "xz80q.dat" file contains the list of stars making the catalog; additional files provide details about double and variable stars included in the XZ80Q. The catalog includes also lists of the various existing names of the stars. (11 data files).

  6. Peptide tessellation yields micrometre-scale collagen triple helices

    NASA Astrophysics Data System (ADS)

    Tanrikulu, I. Caglar; Forticaux, Audrey; Jin, Song; Raines, Ronald T.

    2016-11-01

    Sticky-ended DNA duplexes can associate spontaneously into long double helices; however, such self-assembly is much less developed with proteins. Collagen is the most prevalent component of the extracellular matrix and a common clinical biomaterial. As for natural DNA, the ~103-residue triple helices (~300 nm) of natural collagen are recalcitrant to chemical synthesis. Here we show how the self-assembly of short collagen-mimetic peptides (CMPs) can enable the fabrication of synthetic collagen triple helices that are nearly a micrometre in length. Inspired by the mathematics of tessellations, we derive rules for the design of single CMPs that self-assemble into long triple helices with perfect symmetry. Sticky ends thus created are uniform across the assembly and drive its growth. Enacting this design yields individual triple helices that, in length, match or exceed those in natural collagen and are remarkably thermostable, despite the absence of higher-order association. The symmetric assembly of CMPs provides an enabling platform for the development of advanced materials for medicine and nanotechnology.

  7. World cup soccer players tend to be born with sun and moon in adjacent zodiacal signs

    PubMed Central

    Verhulst, J

    2000-01-01

    The ecliptic elongation of the moon with respect to the sun does not show uniform distribution on the birth dates of the 704 soccer players selected for the 1998 World Cup. However, a uniform distribution is expected on astronomical grounds. The World Cup players show a very pronounced tendency (p = 0.00001) to be born on days when the sun and moon are in adjacent zodiacal signs. Key Words: soccer; World Cup; astrology; moon PMID:11131239

  8. Optimization of high-inclination orbits using planetary flybys for a zodiacal light-imaging mission

    NASA Astrophysics Data System (ADS)

    Soto, Gabriel; Lloyd, James; Savransky, Dmitry; Grogan, Keith; Sinha, Amlan

    2017-09-01

    The zodiacal light caused by interplanetary dust grains is the second-most luminous source in the solar system. The dust grains coalesce into structures reminiscent of early solar system formation; their composition has been predicted through simulations and some edge-on observations but better data is required to validate them. Scattered light from these dust grains presents challenges to exoplanet imaging missions: resolution of their stellar environment is hindered by exozodiacal emissions and therefore sets the size and scope of these imaging missions. Understanding the composition of this interplanetary dust in our solar system requires an imaging mission from a vantage point above the ecliptic plane. The high surface brightness of the zodiacal light requires only a small aperture with moderate sensitivity; therefore a 3cm camera is enough to meet the science goals of the mission at an orbital height of 0.1AU above the ecliptic. A 6U CubeSat is the target mass for this mission which will be a secondary payload detaching from an existing interplanetary mission. Planetary flybys are utilized to produce most of the plane change Δv deep space corrective maneuvers are implemented to optimize each planetary flyby. We developed an algorithm which determines the minimum Δv required to place the CubeSat on a transfer orbit to a planet's sphere of influence and maximizes the resultant orbital height with respect to the ecliptic plane. The satellite could reach an orbital height of 0.22 AU with an Earth gravity assist in late 2024 by boarding the Europa Clipper mission.

  9. Skylab experiment performance evaluation manual. Appendix T: Experiment T027/S073 contamination measurement, photometer and Gegenschein/zodiacal light (MSFC)

    NASA Technical Reports Server (NTRS)

    Meyers, J. E.

    1973-01-01

    A series of analyses for Experiment T027/S073, contamination measurement, photometer and gegenschein/zodiacal light (MSFC), to be used for evaluating the performance of the Skylab corollary experiments under preflight, inflight, and post-flight conditons is presented. Experiment contingency plan workaround procedure and malfunction analyses are presented in order to assist in making the experiment operationally successful.

  10. Single- and two-phase flow in microfluidic porous media analogs based on Voronoi tessellation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wu, Mengjie; Xiao, Feng; Johnson-Paben, Rebecca

    2012-01-01

    The objective of this study was to create a microfluidic model of complex porous media for studying single and multiphase flows. Most experimental porous media models consist of periodic geometries that lend themselves to comparison with well-developed theoretical predictions. However, most real porous media such as geological formations and biological tissues contain a degree of randomness and complexity that is not adequately represented in periodic geometries. To design an experimental tool to study these complex geometries, we created microfluidic models of random homogeneous and heterogeneous networks based on Voronoi tessellations. These networks consisted of approximately 600 grains separated by amore » highly connected network of channels with an overall porosity of 0.11 0.20. We found that introducing heterogeneities in the form of large cavities within the network changed the permeability in a way that cannot be predicted by the classical porosity-permeability relationship known as the Kozeny equation. The values of permeability found in experiments were in excellent agreement with those calculated from three-dimensional lattice Boltzmann simulations. In two-phase flow experiments of oil displacement with water we found that the surface energy of channel walls determined the pattern of water invasion, while the network topology determined the residual oil saturation. These results suggest that complex network topologies lead to fluid flow behavior that is difficult to predict based solely on porosity. The microfluidic models developed in this study using a novel geometry generation algorithm based on Voronoi tessellation are a new experimental tool for studying fluid and solute transport problems within complex porous media.« less

  11. A general representation scheme for crystalline solids based on Voronoi-tessellation real feature values and atomic property data.

    PubMed

    Jalem, Randy; Nakayama, Masanobu; Noda, Yusuke; Le, Tam; Takeuchi, Ichiro; Tateyama, Yoshitaka; Yamazaki, Hisatsugu

    2018-01-01

    Increasing attention has been paid to materials informatics approaches that promise efficient and fast discovery and optimization of functional inorganic materials. Technical breakthrough is urgently requested to advance this field and efforts have been made in the development of materials descriptors to encode or represent characteristics of crystalline solids, such as chemical composition, crystal structure, electronic structure, etc. We propose a general representation scheme for crystalline solids that lifts restrictions on atom ordering, cell periodicity, and system cell size based on structural descriptors of directly binned Voronoi-tessellation real feature values and atomic/chemical descriptors based on the electronegativity of elements in the crystal. Comparison was made vs. radial distribution function (RDF) feature vector, in terms of predictive accuracy on density functional theory (DFT) material properties: cohesive energy (CE), density ( d ), electronic band gap (BG), and decomposition energy (Ed). It was confirmed that the proposed feature vector from Voronoi real value binning generally outperforms the RDF-based one for the prediction of aforementioned properties. Together with electronegativity-based features, Voronoi-tessellation features from a given crystal structure that are derived from second-nearest neighbor information contribute significantly towards prediction.

  12. A general representation scheme for crystalline solids based on Voronoi-tessellation real feature values and atomic property data

    PubMed Central

    Jalem, Randy; Nakayama, Masanobu; Noda, Yusuke; Le, Tam; Takeuchi, Ichiro; Tateyama, Yoshitaka; Yamazaki, Hisatsugu

    2018-01-01

    Abstract Increasing attention has been paid to materials informatics approaches that promise efficient and fast discovery and optimization of functional inorganic materials. Technical breakthrough is urgently requested to advance this field and efforts have been made in the development of materials descriptors to encode or represent characteristics of crystalline solids, such as chemical composition, crystal structure, electronic structure, etc. We propose a general representation scheme for crystalline solids that lifts restrictions on atom ordering, cell periodicity, and system cell size based on structural descriptors of directly binned Voronoi-tessellation real feature values and atomic/chemical descriptors based on the electronegativity of elements in the crystal. Comparison was made vs. radial distribution function (RDF) feature vector, in terms of predictive accuracy on density functional theory (DFT) material properties: cohesive energy (CE), density (d), electronic band gap (BG), and decomposition energy (Ed). It was confirmed that the proposed feature vector from Voronoi real value binning generally outperforms the RDF-based one for the prediction of aforementioned properties. Together with electronegativity-based features, Voronoi-tessellation features from a given crystal structure that are derived from second-nearest neighbor information contribute significantly towards prediction. PMID:29707064

  13. The cosmic spiderweb: equivalence of cosmic, architectural and origami tessellations

    PubMed Central

    Hidding, Johan; Konstantatou, Marina; van de Weygaert, Rien

    2018-01-01

    For over 20 years, the term ‘cosmic web’ has guided our understanding of the large-scale arrangement of matter in the cosmos, accurately evoking the concept of a network of galaxies linked by filaments. But the physical correspondence between the cosmic web and structural engineering or textile ‘spiderwebs’ is even deeper than previously known, and also extends to origami tessellations. Here, we explain that in a good structure-formation approximation known as the adhesion model, threads of the cosmic web form a spiderweb, i.e. can be strung up to be entirely in tension. The correspondence is exact if nodes sampling voids are included, and if structure is excluded within collapsed regions (walls, filaments and haloes), where dark-matter multistreaming and baryonic physics affect the structure. We also suggest how concepts arising from this link might be used to test cosmological models: for example, to test for large-scale anisotropy and rotational flows in the cosmos. PMID:29765637

  14. The cosmic spiderweb: equivalence of cosmic, architectural and origami tessellations.

    PubMed

    Neyrinck, Mark C; Hidding, Johan; Konstantatou, Marina; van de Weygaert, Rien

    2018-04-01

    For over 20 years, the term 'cosmic web' has guided our understanding of the large-scale arrangement of matter in the cosmos, accurately evoking the concept of a network of galaxies linked by filaments. But the physical correspondence between the cosmic web and structural engineering or textile 'spiderwebs' is even deeper than previously known, and also extends to origami tessellations. Here, we explain that in a good structure-formation approximation known as the adhesion model, threads of the cosmic web form a spiderweb, i.e. can be strung up to be entirely in tension. The correspondence is exact if nodes sampling voids are included, and if structure is excluded within collapsed regions (walls, filaments and haloes), where dark-matter multistreaming and baryonic physics affect the structure. We also suggest how concepts arising from this link might be used to test cosmological models: for example, to test for large-scale anisotropy and rotational flows in the cosmos.

  15. The cosmic spiderweb: equivalence of cosmic, architectural and origami tessellations

    NASA Astrophysics Data System (ADS)

    Neyrinck, Mark C.; Hidding, Johan; Konstantatou, Marina; van de Weygaert, Rien

    2018-04-01

    For over 20 years, the term `cosmic web' has guided our understanding of the large-scale arrangement of matter in the cosmos, accurately evoking the concept of a network of galaxies linked by filaments. But the physical correspondence between the cosmic web and structural engineering or textile `spiderwebs' is even deeper than previously known, and also extends to origami tessellations. Here, we explain that in a good structure-formation approximation known as the adhesion model, threads of the cosmic web form a spiderweb, i.e. can be strung up to be entirely in tension. The correspondence is exact if nodes sampling voids are included, and if structure is excluded within collapsed regions (walls, filaments and haloes), where dark-matter multistreaming and baryonic physics affect the structure. We also suggest how concepts arising from this link might be used to test cosmological models: for example, to test for large-scale anisotropy and rotational flows in the cosmos.

  16. A Characterization of the Hot Infrared Background: The Infrared Cirrus, Zodiacal Dust Bands, and Solar System Dust Trails

    DTIC Science & Technology

    1991-04-01

    AD-A239 132 PL -TR-91-2065 A CHARACTERIZATION OF THE HOT INFRARED BACKGROUND: THE INFRARED CIRRUS, ZODIACAL DUST BANDS, AND SOLAR SYSTEM DUST TRAILS F...addressee is no longer employed by your organization, please notify OL-AA PL /IMA, Hanscom AFB, MA 01731. This will assist us in maintaining a current...DECLASSIFICATION /DOWNGRADING SCHEDULE Distribution unlimited 4 PERFORMING ORGANIZATION REPORT NUMBER(S) S MONITORING ORGANIZATION REPORT NUMBER(S) PL -TR-91-2065 6a

  17. Using Voronoi Tessellations to identify groups in N-body Simulation

    NASA Astrophysics Data System (ADS)

    Gonzalez, R. E.; Theuns, T.

    Dark matter N-body simulations often use a friends-of-friends (FOF) group finder to link together particles above a specified density threshold. An over density of 200 picks-out objects that can be identified with virialised dark matter haloes, based on the spherical collapse model for the formation of structure. When the halo contains significant substructure, as is the case in very high resolution simulations, then FOF will simply link all substructure to the parent halo. Many cosmological simulations now also include gas and stars, and these are often distributed differently from the dark matter. It is then not clear whether the structures identified by FOF are very physical. Here we use Voronoi tesselations to identify structures in hydrodynamical cosmological simulations, that contain dark matter, gas and stars. This adaptive technique allows accurate estimates of densities, and density gradients, for a non-structured distribution of points. We discuss how these estimates allow us to identify structures in the dark matter that can be identified with haloes, and in the stars, to identify galaxies.

  18. The US Naval Observatory Zodiacal Zone Catalog (Douglas and Harrington 1990): Documentation for the machine-readable version

    NASA Technical Reports Server (NTRS)

    Warren, Wayne H., Jr.

    1990-01-01

    The machine readable version of the catalog, as it is currently being distributed from the Astronomical Data Center, is described. The Zodiacal Zone Catalog is a catalog of positions and proper motions for stars in the magnitude range where m sub v is between 4 and 10, lying within 16 deg of the ecliptic and north of declination -30 deg. The catalog contains positions and proper motions, at epoch, for equator and equinox J2000.0, magnitudes and spectral types taken mostly from the Smithsonian Astrophysical Observatory Star Catalog, and reference positions and proper motions for equinox and epoch B1950.0.

  19. The S sub 10 /V/ unit of surface brightness. [for zodiacal light measurement

    NASA Technical Reports Server (NTRS)

    Sparrow, J. G.; Weinberg, J. L.

    1976-01-01

    Some discrepancies in the use of the unit of zodiacal light measurements - S sub 10 (V), which is the equivalent number of tenth magnitude stars of solar spectral type per square degree - are discussed. It is suggested that: (1) the S sub 10 (V) unit be understood to represent 10th magnitude solar (G2V) stars per square degree at mean solar distance, (2) the V refers to the visual color in the UBV system defined by Johnson and Morgan (1953), (3) the apparent solar visual magnitude be taken as -26.73 and the B-V index as .63, (4) the solar spectral irradiance values of Labs and Neckel (1970) be used, and (5) when using Vega as a standard to obtain brightnesses in S sub 10 (V), +.04 be used as its magnitude at all wavelengths and the irradiance values of Hayes and Latham (1975) be used.

  20. Improve strategic supplier performance using DMAIC to develop a Quality Improvement Plan

    NASA Astrophysics Data System (ADS)

    Jardim, Kevin P.

    Supplier performance that meets the requirements of the customer has long plagued quality professionals. Despite the vast efforts by organizations to improve supplier performance, little has been done to standardize the plan to improve performance. This project presents a guideline and problem-solving strategy using a Define, Measure, Analyze, Improve, and Control (DMAIC) structured tool that will assist in the management and improvement of supplier performance. An analysis of benchmarked Quality Improvement Plans indicated that this topic needs more focus on how to accomplish improved supplier performance. This project is part of a growing body of supplier continuous improvement efforts. With the input of Zodiac Aerospace quality professionals this project's results provide a solution to Quality Improvement Plans and show objective evidence of its benefits. This project contributes to the future research on similar topics.

  1. A tesselated probabilistic representation for spatial robot perception and navigation

    NASA Technical Reports Server (NTRS)

    Elfes, Alberto

    1989-01-01

    The ability to recover robust spatial descriptions from sensory information and to efficiently utilize these descriptions in appropriate planning and problem-solving activities are crucial requirements for the development of more powerful robotic systems. Traditional approaches to sensor interpretation, with their emphasis on geometric models, are of limited use for autonomous mobile robots operating in and exploring unknown and unstructured environments. Here, researchers present a new approach to robot perception that addresses such scenarios using a probabilistic tesselated representation of spatial information called the Occupancy Grid. The Occupancy Grid is a multi-dimensional random field that maintains stochastic estimates of the occupancy state of each cell in the grid. The cell estimates are obtained by interpreting incoming range readings using probabilistic models that capture the uncertainty in the spatial information provided by the sensor. A Bayesian estimation procedure allows the incremental updating of the map using readings taken from several sensors over multiple points of view. An overview of the Occupancy Grid framework is given, and its application to a number of problems in mobile robot mapping and navigation are illustrated. It is argued that a number of robotic problem-solving activities can be performed directly on the Occupancy Grid representation. Some parallels are drawn between operations on Occupancy Grids and related image processing operations.

  2. A multiresolution method for climate system modeling: application of spherical centroidal Voronoi tessellations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ringler, Todd; Ju, Lili; Gunzburger, Max

    2008-11-14

    During the next decade and beyond, climate system models will be challenged to resolve scales and processes that are far beyond their current scope. Each climate system component has its prototypical example of an unresolved process that may strongly influence the global climate system, ranging from eddy activity within ocean models, to ice streams within ice sheet models, to surface hydrological processes within land system models, to cloud processes within atmosphere models. These new demands will almost certainly result in the develop of multiresolution schemes that are able, at least regionally, to faithfully simulate these fine-scale processes. Spherical centroidal Voronoimore » tessellations (SCVTs) offer one potential path toward the development of a robust, multiresolution climate system model components. SCVTs allow for the generation of high quality Voronoi diagrams and Delaunay triangulations through the use of an intuitive, user-defined density function. In each of the examples provided, this method results in high-quality meshes where the quality measures are guaranteed to improve as the number of nodes is increased. Real-world examples are developed for the Greenland ice sheet and the North Atlantic ocean. Idealized examples are developed for ocean–ice shelf interaction and for regional atmospheric modeling. In addition to defining, developing, and exhibiting SCVTs, we pair this mesh generation technique with a previously developed finite-volume method. Our numerical example is based on the nonlinear, shallow water equations spanning the entire surface of the sphere. This example is used to elucidate both the potential benefits of this multiresolution method and the challenges ahead.« less

  3. Tessellated permanent magnet circuits for flow-through, open gradient separations of weakly magnetic materials.

    PubMed

    Moore, Lee R; Williams, P Stephen; Chalmers, Jeffrey J; Zborowski, Maciej

    2017-04-01

    Emerging microfluidic-based cell assays favor label-free red blood cell (RBC) depletion. Magnetic separation of RBC is possible because of the paramagnetism of deoxygenated hemoglobin but the process is slow for open-gradient field configurations. In order to increase the throughput, periodic arrangements of the unit magnets were considered, consisting of commercially available Nd-Fe-B permanent magnets and soft steel flux return pieces. The magnet design is uniquely suitable for multiplexing by magnet tessellation, here meaning the tiling of the magnet assembly cross-sectional plane by periodic repetition of the magnet and the flow channel shapes. The periodic pattern of magnet magnetizations allows a reduction of the magnetic material per channel with minimal distortion of the field cylindrical symmetry inside the magnet apertures. A number of such magnet patterns are investigated for separator performance, size and economy with the goal of designing an open-gradient magnetic separator capable of reducing the RBC number concentration a hundred-fold in 1 mL whole blood per hour.

  4. Tessellated gold nanostructures from Au144(SCH2CH2Ph)60 molecular precursors and their use in organic solar cell enhancement

    NASA Astrophysics Data System (ADS)

    Bauld, Reg; Hesari, Mahdi; Workentin, Mark S.; Fanchini, Giovanni

    2014-06-01

    We report for the first time the fabrication of nanocomposite hole-blocking layers consisting of poly-3,4-ethylene-dioxythiophene:poly-styrene-sulfonate (PEDOT:PSS) thin films incorporating networks of gold nanoparticles assembled from Au144(SCH2CH2Ph)60, a molecular gold precursor. These thin films can be prepared reproducibly on indium tin oxide by spinning on it Au144(SCH2CH2Ph)60 solutions in chlorobenzene, annealing the resulting thin film at 400 °C, and subsequently spinning PEDOT:PSS on top. The use of our nanocomposite hole-blocking layers for enhancing the photoconversion efficiency of bulk heterojunction organic solar cells is demonstrated. By varying the concentration of Au144(SCH2CH2Ph)60 in the starting solution and the annealing time, different gold nanostructures were obtained ranging from individual gold nanoparticles (AuNPs) to tessellated networks of gold nanostructures (Tess-AuNPs). Improvement in organic solar cell efficiencies up to 10% relative to a reference cell is demonstrated with Tess-AuNPs embedded in PEDOT:PSS.

  5. Complex supramolecular interfacial tessellation through convergent multi-step reaction of a dissymmetric simple organic precursor

    NASA Astrophysics Data System (ADS)

    Zhang, Yi-Qi; Paszkiewicz, Mateusz; Du, Ping; Zhang, Liding; Lin, Tao; Chen, Zhi; Klyatskaya, Svetlana; Ruben, Mario; Seitsonen, Ari P.; Barth, Johannes V.; Klappenberger, Florian

    2018-03-01

    Interfacial supramolecular self-assembly represents a powerful tool for constructing regular and quasicrystalline materials. In particular, complex two-dimensional molecular tessellations, such as semi-regular Archimedean tilings with regular polygons, promise unique properties related to their nontrivial structures. However, their formation is challenging, because current methods are largely limited to the direct assembly of precursors, that is, where structure formation relies on molecular interactions without using chemical transformations. Here, we have chosen ethynyl-iodophenanthrene (which features dissymmetry in both geometry and reactivity) as a single starting precursor to generate the rare semi-regular (3.4.6.4) Archimedean tiling with long-range order on an atomically flat substrate through a multi-step reaction. Intriguingly, the individual chemical transformations converge to form a symmetric alkynyl-Ag-alkynyl complex as the new tecton in high yields. Using a combination of microscopy and X-ray spectroscopy tools, as well as computational modelling, we show that in situ generated catalytic Ag complexes mediate the tecton conversion.

  6. Tessellated permanent magnet circuits for flow-through, open gradient separations of weakly magnetic materials

    PubMed Central

    Moore, Lee R.; Williams, P. Stephen; Chalmers, Jeffrey J.; Zborowski, Maciej

    2017-01-01

    Emerging microfluidic-based cell assays favor label-free red blood cell (RBC) depletion. Magnetic separation of RBC is possible because of the paramagnetism of deoxygenated hemoglobin but the process is slow for open-gradient field configurations. In order to increase the throughput, periodic arrangements of the unit magnets were considered, consisting of commercially available Nd-Fe-B permanent magnets and soft steel flux return pieces. The magnet design is uniquely suitable for multiplexing by magnet tessellation, here meaning the tiling of the magnet assembly cross-sectional plane by periodic repetition of the magnet and the flow channel shapes. The periodic pattern of magnet magnetizations allows a reduction of the magnetic material per channel with minimal distortion of the field cylindrical symmetry inside the magnet apertures. A number of such magnet patterns are investigated for separator performance, size and economy with the goal of designing an open-gradient magnetic separator capable of reducing the RBC number concentration a hundred-fold in 1 mL whole blood per hour. PMID:29104346

  7. The Origin of the Excess Near-Infrared Diffuse Sky Brightness: Population III Stars or Zodiacal Light?

    NASA Technical Reports Server (NTRS)

    Dwek, Eli

    2006-01-01

    The intensity of the diffuse 1 to 5 micron sky emission from which solar system and Galactic foregrounds have been subtracted is in excess of that expected from energy released by galaxies and stars that formed during the z < 5 redshift interval. The spectral signature of this excess near-infrared background light (NIRBL) component is almost identical to that of reflected sunlight from the interplanetary dust cloud, and could therefore be the result of the incomplete subtraction of this foreground emission component from the diffuse sky maps. Alternatively, this emission component could be extragalactic. Its spectral signature is consistent with that of redshifted continuum and recombination line emission from H-II regions formed by the first generation of very massive stars. In this talk I will present the implications of this excess emission for our understanding of the zodiacal dust cloud, the formation rate of Pop III stars, and the TeV gamma-ray opacity to nearby blazars.

  8. A tesselation-based model for intensity estimation and laser plasma interactions calculations in three dimensions

    NASA Astrophysics Data System (ADS)

    Colaïtis, A.; Chapman, T.; Strozzi, D.; Divol, L.; Michel, P.

    2018-03-01

    A three-dimensional laser propagation model for computation of laser-plasma interactions is presented. It is focused on indirect drive geometries in inertial confinement fusion and formulated for use at large temporal and spatial scales. A modified tesselation-based estimator and a relaxation scheme are used to estimate the intensity distribution in plasma from geometrical optics rays. Comparisons with reference solutions show that this approach is well-suited to reproduce realistic 3D intensity field distributions of beams smoothed by phase plates. It is shown that the method requires a reduced number of rays compared to traditional rigid-scale intensity estimation. Using this field estimator, we have implemented laser refraction, inverse-bremsstrahlung absorption, and steady-state crossed-beam energy transfer with a linear kinetic model in the numerical code Vampire. Probe beam amplification and laser spot shapes are compared with experimental results and pf3d paraxial simulations. These results are promising for the efficient and accurate computation of laser intensity distributions in holhraums, which is of importance for determining the capsule implosion shape and risks of laser-plasma instabilities such as hot electron generation and backscatter in multi-beam configurations.

  9. The Forest Method as a New Parallel Tree Method with the Sectional Voronoi Tessellation

    NASA Astrophysics Data System (ADS)

    Yahagi, Hideki; Mori, Masao; Yoshii, Yuzuru

    1999-09-01

    We have developed a new parallel tree method which will be called the forest method hereafter. This new method uses the sectional Voronoi tessellation (SVT) for the domain decomposition. The SVT decomposes a whole space into polyhedra and allows their flat borders to move by assigning different weights. The forest method determines these weights based on the load balancing among processors by means of the overload diffusion (OLD). Moreover, since all the borders are flat, before receiving the data from other processors, each processor can collect enough data to calculate the gravity force with precision. Both the SVT and the OLD are coded in a highly vectorizable manner to accommodate on vector parallel processors. The parallel code based on the forest method with the Message Passing Interface is run on various platforms so that a wide portability is guaranteed. Extensive calculations with 15 processors of Fujitsu VPP300/16R indicate that the code can calculate the gravity force exerted on 105 particles in each second for some ideal dark halo. This code is found to enable an N-body simulation with 107 or more particles for a wide dynamic range and is therefore a very powerful tool for the study of galaxy formation and large-scale structure in the universe.

  10. A CMB foreground study in WMAP data: Extragalactic point sources and zodiacal light emission

    NASA Astrophysics Data System (ADS)

    Chen, Xi

    The Cosmic Microwave Background (CMB) radiation is the remnant heat from the Big Bang. It serves as a primary tool to understand the global properties, content and evolution of the universe. Since 2001, NASA's Wilkinson Microwave Anisotropy Probe (WMAP) satellite has been napping the full sky anisotropy with unprecedented accuracy, precision and reliability. The CMB angular power spectrum calculated from the WMAP full sky maps not only enables accurate testing of cosmological models, but also places significant constraints on model parameters. The CMB signal in the WMAP sky maps is contaminated by microwave emission from the Milky Way and from extragalactic sources. Therefore, in order to use the maps reliably for cosmological studies, the foreground signals must be well understood and removed from the maps. This thesis focuses on the separation of two foreground contaminants from the WMAP maps: extragalactic point sources and zodiacal light emission. Extragalactic point sources constitute the most important foreground on small angular scales. Various methods have been applied to the WMAP single frequency maps to extract sources. However, due to the limited angular resolution of WMAP, it is possible to confuse positive CMB excursions with point sources or miss sources that are embedded in negative CMB fluctuations. We present a novel CMB-free source finding technique that utilizes the spectrum difference of point sources and CMB to form internal linear combinations of multifrequency maps to suppress the CMB and better reveal sources. When applied to the WMAP 41, 64 and 94 GHz maps, this technique has not only enabled detection of sources that are previously cataloged by independent methods, but also allowed disclosure of new sources. Without the noise contribution from the CMB, this method responds rapidly with the integration time. The number of detections varies as 0( t 0.72 in the two-band search and 0( t 0.70 in the three-band search from one year to five years

  11. 2D wireless sensor network deployment based on Centroidal Voronoi Tessellation

    NASA Astrophysics Data System (ADS)

    Iliodromitis, Athanasios; Pantazis, George; Vescoukis, Vasileios

    2017-06-01

    In recent years, Wireless Sensor Networks (WSNs) have rapidly evolved and now comprise a powerful tool in monitoring and observation of the natural environment, among other fields. The use of WSNs is critical in early warning systems, which are of high importance today. In fact, WSNs are adopted more and more in various applications, e.g. for fire or deformation detection. The optimum deployment of sensors is a multi-dimensional problem, which has two main components; network and positioning approach. Although lots of work has dealt with the issue, most of it emphasizes on mere network approach (communication, energy consumption) and not on the topography (positioning) of the sensors in achieving ideal geometry. In some cases, it is hard or even impossible to achieve perfect geometry in nodes' deployment. The ideal and desirable scenario of nodes arranged in square or hexagonal grid would raise extremely the cost of the network, especially in unfriendly or hostile environments. In such environments the positions of the sensors have to be chosen among a list of possible points, which in most cases are randomly distributed. This constraint has to be taken under consideration during the WSN planning. Full geographical coverage is in some applications of the same, if not of greater, importance than the network coverage. Cost is a crucial factor at network planning and given that resources are often limited, what matters, is to cover the whole area with the minimum number of sensors. This paper suggests a deployment method for nodes, in large scale and high density WSNs, based on Centroidal Voronoi Tessellation (CVT). It approximates the solution through the geometry of the random points and proposes a deployment plan, for the given characteristics of the study area, in order to achieve a deployment as near as possible to the ideal one.

  12. Alanine aminotransferase and mortality in patients with type 2 diabetes (ZODIAC-38).

    PubMed

    Deetman, Petronella E; Alkhalaf, Alaa; Landman, Gijs W D; Groenier, Klaas H; Kootstra-Ros, Jenny E; Navis, Gerjan; Bilo, Henk J G; Kleefstra, Nanne; Bakker, Stephan J L

    2015-08-01

    Combined data suggest a bimodal association of alanine aminotransferase (ALT) with mortality in the general population. Little is known about the association of ALT with mortality in patients with type 2 diabetes. We therefore investigated the association of ALT with all-cause, cardiovascular and noncardiovascular mortality in patients with type 2 diabetes. A prospective study was performed in patients with type 2 diabetes, treated in primary care, participating in the Zwolle Outpatient Diabetes project Integrating Available Care (ZODIAC) study. Cox regression analyses were performed to determine the associations of log2 -transformed baseline ALT with all-cause, cardiovascular and noncardiovascular mortality. In 1187 patients with type 2 diabetes (67 ± 12 years, 45% female), ALT levels were 11 (8-16) U/L. During median follow-up for 11.1 (6.1-14.0) years, 553 (47%) patients died, with 238 (20%) attributable to cardiovascular causes. Overall, ALT was inversely associated with all-cause mortality (hazard ratio [HR] 0.81; 95% confidence interval [CI] 0.72-0.92), independently of potential confounders. This was less attributable to cardiovascular mortality (HR 0.87; 95% CI 0.72-1.05), than to noncardiovascular mortality (HR 0.77; 95% CI 0.65-0.90). Despite the overall inverse association of ALT with mortality, it appeared that a bimodal association with all-cause mortality was present with increasing risk for levels of ALT above normal (P = 0.003). In patients with type 2 diabetes, low levels of ALT are associated with an increased risk of all-cause mortality, in particular noncardiovascular mortality, compared to normal levels of ALT, while risk again starts to increase when levels are above normal. © 2015 Stichting European Society for Clinical Investigation Journal Foundation.

  13. Using Delaunay triangulation and Voronoi tessellation to predict the toxicities of binary mixtures containing hormetic compound

    NASA Astrophysics Data System (ADS)

    Qu, Rui; Liu, Shu-Shen; Zheng, Qiao-Feng; Li, Tong

    2017-03-01

    Concentration addition (CA) was proposed as a reasonable default approach for the ecological risk assessment of chemical mixtures. However, CA cannot predict the toxicity of mixture at some effect zones if not all components have definite effective concentrations at the given effect, such as some compounds induce hormesis. In this paper, we developed a new method for the toxicity prediction of various types of binary mixtures, an interpolation method based on the Delaunay triangulation (DT) and Voronoi tessellation (VT) as well as the training set of direct equipartition ray design (EquRay) mixtures, simply IDVequ. At first, the EquRay was employed to design the basic concentration compositions of five binary mixture rays. The toxic effects of single components and mixture rays at different times and various concentrations were determined by the time-dependent microplate toxicity analysis. Secondly, the concentration-toxicity data of the pure components and various mixture rays were acted as a training set. The DT triangles and VT polygons were constructed by various vertices of concentrations in the training set. The toxicities of unknown mixtures were predicted by the linear interpolation and natural neighbor interpolation of vertices. The IDVequ successfully predicted the toxicities of various types of binary mixtures.

  14. Using Delaunay triangulation and Voronoi tessellation to predict the toxicities of binary mixtures containing hormetic compound

    PubMed Central

    Qu, Rui; Liu, Shu-Shen; Zheng, Qiao-Feng; Li, Tong

    2017-01-01

    Concentration addition (CA) was proposed as a reasonable default approach for the ecological risk assessment of chemical mixtures. However, CA cannot predict the toxicity of mixture at some effect zones if not all components have definite effective concentrations at the given effect, such as some compounds induce hormesis. In this paper, we developed a new method for the toxicity prediction of various types of binary mixtures, an interpolation method based on the Delaunay triangulation (DT) and Voronoi tessellation (VT) as well as the training set of direct equipartition ray design (EquRay) mixtures, simply IDVequ. At first, the EquRay was employed to design the basic concentration compositions of five binary mixture rays. The toxic effects of single components and mixture rays at different times and various concentrations were determined by the time-dependent microplate toxicity analysis. Secondly, the concentration-toxicity data of the pure components and various mixture rays were acted as a training set. The DT triangles and VT polygons were constructed by various vertices of concentrations in the training set. The toxicities of unknown mixtures were predicted by the linear interpolation and natural neighbor interpolation of vertices. The IDVequ successfully predicted the toxicities of various types of binary mixtures. PMID:28287626

  15. Characterization of 3D Voronoi Tessellation Nearest Neighbor Lipid Shells Provides Atomistic Lipid Disruption Profile of Protein Containing Lipid Membranes

    PubMed Central

    Cheng, Sara Y.; Duong, Hai V.; Compton, Campbell; Vaughn, Mark W.; Nguyen, Hoa; Cheng, Kwan H.

    2015-01-01

    Quantifying protein-induced lipid disruptions at the atomistic level is a challenging problem in membrane biophysics. Here we propose a novel 3D Voronoi tessellation nearest-atom-neighbor shell method to classify and characterize lipid domains into discrete concentric lipid shells surrounding membrane proteins in structurally heterogeneous lipid membranes. This method needs only the coordinates of the system and is independent of force fields and simulation conditions. As a proof-of-principle, we use this multiple lipid shell method to analyze the lipid disruption profiles of three simulated membrane systems: phosphatidylcholine, phosphatidylcholine/cholesterol, and beta-amyloid/phosphatidylcholine/cholesterol. We observed different atomic volume disruption mechanisms due to cholesterol and beta-amyloid Additionally, several lipid fractional groups and lipid-interfacial water did not converge to their control values with increasing distance or shell order from the protein. This volume divergent behavior was confirmed by bilayer thickness and chain orientational order calculations. Our method can also be used to analyze high-resolution structural experimental data. PMID:25637891

  16. Lifestyle and emotional well-being in men and women with type 2 diabetes (e-VitaDM-4; ZODIAC-48).

    PubMed

    Hendriks, Steven H; van Soldt, Evelien G W; van Vugt, Michael; Groenier, Klaas H; Roelofsen, Yvonne; Maas, Angela H E M; Bilo, Henk J G; Kleefstra, Nanne; van Hateren, Kornelis J J

    2017-12-01

    Whether lifestyle is associated with well-being in patients with type 2 diabetes (T2D) is largely unknown. Uncovering and clarifying associations between these constructs may lead to new strategies for improving both. The aim was to investigate the relationship between lifestyle and well-being, focussing on gender differences. This cross-sectional study included 1085 patients with T2D that participated in the e-Vita part of the Zwolle outpatient diabetes project integrating available care (ZODIAC) study. Patients were included from May 2012 until September 2014 from 52 general practices. Emotional well-being was assessed with the World Health Organization-5 well-being index (WHO-5). Lifestyle information on body mass index, smoking, physical activity and alcohol use was extracted from self-reported questionnaires. Multiple linear regression analyses were used. After adjustment for other lifestyle factors, physical activity, smoking and drinking 22-35 alcohol consumptions per week were associated with the WHO-5 score in men and physical activity and smoking were associated with the WHO-5 score in women. In the fully adjusted analyses for the total study population, physical activity and smoking were still associated with the WHO-5 score (b = 1.1, P < .001 and b =-3.1, P = .018, respectively). In the fully adjusted analyses stratified to gender only physical activity was associated with the WHO-5 score (in men: b =0.8, P = .006, in women: b = 1.4, P = .001). This study shows a negative, non-clinically relevant association between smoking and emotional well-being in the total population with T2D and a positive, non-clinically relevant association between physical activity and emotional well-being in both men and women with T2D.

  17. Dynamical Model for the Zodiacal Cloud and Sporadic Meteors

    NASA Astrophysics Data System (ADS)

    Nesvorný, David; Janches, Diego; Vokrouhlický, David; Pokorný, Petr; Bottke, William F.; Jenniskens, Peter

    2011-12-01

    The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving at the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer (gsim 105 yr at 1 AU) than postulated in the standard collisional models (~104 yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) × 1011 km2 and ~4 × 1019 g, respectively, in a good agreement with previous studies. The mass input required to keep the zodiacal cloud in a steady state is estimated to be ~104-105 kg s-1. The input is up to ~10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 μm and 1 cm is found to be ~15,000 tons yr-1 (factor of two uncertainty), which is a large share of the accretion flux measured by the Long Term Duration

  18. Studying the Fine Structure and Temporal Variations of the Zodiacal Cloud and Asteroidal Dust Bands Using the 3-Year Near-IR COBE-DIRBE Data

    NASA Technical Reports Server (NTRS)

    Jayaraman, Sumita

    1999-01-01

    The report presents the results of the data analyses of the DIRBE-COBE data set to study the structure of the zodiacal cloud in the near-infrared wavebands at 1.2, 2.2, and 3.4 microns. The cloud has been divided into two components which have been analyzed and studied separately. The annual variation of the flux in the smooth or low frequency component has been measured in all three bands and the presence of any asymmetries due to the Earth's resonant ring have been studied. The high frequency component which primarily consisted of the asteroidal dust bands. Extensive and careful co-addition was done to extract the central bands in all three wavebands. The ten-degree bands are present in the 1.2 and 2.2 microns but not in the 3.4 micron waveband.

  19. A Global 3D P-Velocity Model of the Earth’s Crust and Mantle for Improved Event Location

    DTIC Science & Technology

    2011-09-01

    starting model, we use a simplified layer crustal model derived from the NNSA Unified model in Eurasia and Crust 2.0 model everywhere else, over a...geographic and radial dimensions. For our starting model, we use a simplified layer crustal model derived from the NNSA Unified model in Eurasia and...tessellation with 4° triangles to the transition zone and upper mantle, and a third tessellation with variable resolution to all crustal layers. The

  20. Including crystal structure attributes in machine learning models of formation energies via Voronoi tessellations

    NASA Astrophysics Data System (ADS)

    Ward, Logan; Liu, Ruoqian; Krishna, Amar; Hegde, Vinay I.; Agrawal, Ankit; Choudhary, Alok; Wolverton, Chris

    2017-07-01

    While high-throughput density functional theory (DFT) has become a prevalent tool for materials discovery, it is limited by the relatively large computational cost. In this paper, we explore using DFT data from high-throughput calculations to create faster, surrogate models with machine learning (ML) that can be used to guide new searches. Our method works by using decision tree models to map DFT-calculated formation enthalpies to a set of attributes consisting of two distinct types: (i) composition-dependent attributes of elemental properties (as have been used in previous ML models of DFT formation energies), combined with (ii) attributes derived from the Voronoi tessellation of the compound's crystal structure. The ML models created using this method have half the cross-validation error and similar training and evaluation speeds to models created with the Coulomb matrix and partial radial distribution function methods. For a dataset of 435 000 formation energies taken from the Open Quantum Materials Database (OQMD), our model achieves a mean absolute error of 80 meV/atom in cross validation, which is lower than the approximate error between DFT-computed and experimentally measured formation enthalpies and below 15% of the mean absolute deviation of the training set. We also demonstrate that our method can accurately estimate the formation energy of materials outside of the training set and be used to identify materials with especially large formation enthalpies. We propose that our models can be used to accelerate the discovery of new materials by identifying the most promising materials to study with DFT at little additional computational cost.

  1. Calcified cartilage or bone? Collagens in the tessellated endoskeletons of cartilaginous fish (sharks and rays).

    PubMed

    Seidel, Ronald; Blumer, Michael; Pechriggl, Elisabeth-Judith; Lyons, Kady; Hall, Brian K; Fratzl, Peter; Weaver, James C; Dean, Mason N

    2017-10-01

    The primary skeletal tissue in elasmobranchs -sharks, rays and relatives- is cartilage, forming both embryonic and adult endoskeletons. Only the skeletal surface calcifies, exhibiting mineralized tiles (tesserae) sandwiched between a cartilage core and overlying fibrous perichondrium. These two tissues are based on different collagens (Coll II and I, respectively), fueling a long-standing debate as to whether tesserae are more like calcified cartilage or bone (Coll 1-based) in their matrix composition. We demonstrate that stingray (Urobatis halleri) tesserae are bipartite, having an upper Coll I-based 'cap' that merges into a lower Coll II-based 'body' zone, although tesserae are surrounded by cartilage. We identify a 'supratesseral' unmineralized cartilage layer, between tesserae and perichondrium, distinguished from the cartilage core in containing Coll I and X (a common marker for mammalian mineralization), in addition to Coll II. Chondrocytes within tesserae appear intact and sit in lacunae filled with Coll II-based matrix, suggesting tesserae originate in cartilage, despite comprising a diversity of collagens. Intertesseral joints are also complex in their collagenous composition, being similar to supratesseral cartilage closer to the perichondrium, but containing unidentified fibrils nearer the cartilage core. Our results indicate a unique potential for tessellated cartilage in skeletal biology research, since it lacks features believed diagnostic for vertebrate cartilage mineralization (e.g. hypertrophic and apoptotic chondrocytes), while offering morphologies amenable for investigating the regulation of complex mineralized ultrastructure and tissues patterned on multiple collagens. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Dynamical Model for the Zodiacal Cloud and Sporadic Meteors

    NASA Technical Reports Server (NTRS)

    Nesvorny, David; Janches, Diego; Vokrouhlicky, David; Pokorny, Petr; Bottke, William F.; Jenniskens, Peter

    2011-01-01

    The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving to the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer (approx. > 10(exp 5) yr at 1 AU) than postulated in the standard collisional models (approx 10(exp 4) yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite (IRAS) to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) 10(exp 11) sq km and approx. 4 10(exp 19) g, respectively, in a good agreement with previous studies. The mass input required to keep the Zodiacal Cloud (ZC) in a steady state is estimated to be approx. 10(exp 4)-10(exp 5) kg/s. The input is up to approx 10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes, and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 micron and 1 cm is found to be approx 15,000 tons/yr (factor of 2 uncertainty), which is

  3. DYNAMICAL MODEL FOR THE ZODIACAL CLOUD AND SPORADIC METEORS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nesvorny, David; Vokrouhlicky, David; Pokorny, Petr

    2011-12-20

    The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving atmore » the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer ({approx}> 10{sup 5} yr at 1 AU) than postulated in the standard collisional models ({approx}10{sup 4} yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) Multiplication-Sign 10{sup 11} km{sup 2} and {approx}4 Multiplication-Sign 10{sup 19} g, respectively, in a good agreement with previous studies. The mass input required to keep the zodiacal cloud in a steady state is estimated to be {approx}10{sup 4}-10{sup 5} kg s{sup -1}. The input is up to {approx}10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 {mu}m and 1 cm is found to be {approx

  4. A Global 3D P-Velocity Model of the Earth’s Crust and Mantle for Improved Event Location -- SALSA3D

    DTIC Science & Technology

    2010-09-01

    incorporates variable resolution in both the geographic and radial dimensions. For our starting model, we use a simplified two layer crustal model derived from... crustal model derived from the Crust 2.0 model over a uniform AK135 mantle. Sufficient damping is used to reduce velocity adjustments so that ray path...upper mantle, and a third tessellation with variable resolution to all crustal layers. The crustal tessellation (not shown) has 2° triangles in oceanic

  5. Modeling the effects of an offset of the center of symmetry in the zodiacal cloud

    NASA Astrophysics Data System (ADS)

    Holmes, E. K.; Dermott, S. F.; Xu, Y. L.; Wyatt, M.; Jayaraman, S.

    1998-04-01

    There is a possible connection between structure in circumstellar dust clouds and the presence of planets, our own zodiacal cloud being the prime example. Asymmetries in such clouds could be diagnostic of planets which would be otherwise undetectable. One such feature is an offset of the center of symmetry of the disk with respect to the central star. The offset is caused by the forced eccentricities (ef) of particles in the cloud. The orbit of a particle can be described by a set of five orbital elements: the semi-major axis (a), eccentricity (e), inclination (I), longitude of ascending node (Omega) and the argument of pericenter (omega). In low order secular perturbation theory, osculating elements of small bodies are decomposed into proper and forced elements. The proper elements are dependent on initial conditions while the forced elements are imposed on the particle's orbit by the gravitational perturbations of the planets. This decomposition is still applicable in the presence of drag forces. We compare COBE observations of the variation in average polar brightness of the background cloud, (N + S)/2, with ecliptic longitude of Earth with those of a model cloud made of asteroidal particles which populate the inner solar system according to a 1/rgamma where (gamma) = 1 (Poynting Robertson light drag) distribution. The variation with ecliptic longitude of Earth in mean polar brightness is shown in for the 25 micron waveband. Sine curves are fit to both the COBE observations and the model. The variation in (N+S)/2 with ecliptic longitude of Earth can be represented as a superposition of two sine curves: one for the variation in (N + S)/2 due to the Earth's eccentric orbit and the other for the variation in (N + S)/2 due to the forced eccentricities of particles in the cloud. If the cloud were symmetric about the Sun (i.e., if there were no offset), the maximum and minimum brightnesses of the cloud would occur at perihelion and aphelion, respectively. Looking at

  6. Effect of inter-species selective interactions on the thermodynamics and nucleation free-energy barriers of a tessellating polyhedral compound

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Escobedo, Fernando A., E-mail: fe13@cornell.edu

    The phase behavior and the homogeneous nucleation of an equimolar mixture of octahedra and cuboctahedra are studied using thermodynamic integration, Gibbs-Duhem integration, and umbrella sampling simulations. The components of this mixture are modeled as polybead objects of equal edge lengths so that they can assemble into a space-filling compound with the CsCl crystal structure. Taking as reference the hard-core system where the compound crystal does not spontaneously nucleate, we quantified the effect of inter-species selective interactions on facilitating the disorder-to-order transition. Facet selective and facet non-selective inter-species attractions were considered, and while the former was expectedly more favorable toward themore » target tessellating structure, the latter was found to be similarly effective in nucleating the crystal compound. Ranges for the strength of attractions and degree of supersaturation were identified where the nucleation free-energy barrier was small enough to foretell a fast process but large enough to prevent spinodal fluctuations that can trap the system in dense metastable states lacking long-range order. At those favorable conditions, the tendency toward the local orientational order favored by packing entropy is amplified and found to play a key role seeding nuclei with the CsCl structure.« less

  7. The Zodiacal Cloud Model applied to the Martian atmosphere. Diurnal variations in meteoric ion layers

    NASA Astrophysics Data System (ADS)

    Carrillo-Sánchez, J. D.; Plane, J. M. C.; Withers, P.; Fallows, K.; Nesvorny, D.; Pokorný, P.

    2016-12-01

    Sporadic metal layers have been detected in the Martian atmosphere by radio occultation measurements using the Mars Express Orbiter and Mars Global Surveyor spacecraft. More recently, metallic ion layers produced by the meteor storm event following the close encounter between Comet Siding Spring (C/2013 A1) and Mars were identified by the Imaging UltraViolet Spectrograph (IUVS) and the Neutral Gas and Ion Mass Spectrometer (NGIMS) on the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. Work is now in progress to detect the background metal layers produced by the influx of sporadic meteors. In this study we predict the likely appearance of these layers. The Zodiacal Dust Cloud (ZDC) model for particle populations released by asteroids (AST), and dust grains from Jupiter Family Comets (JFCs) and Halley-Type Comets (HTCs) has been combined with a Monte Carlo sampling method and the Chemical ABlation MODel (CABMOD) to predict the ablation rates of Na, K, Fe, Si, Mg, Ca and Al above 40 km altitude in the Martian atmosphere. CABMOD considers the standard treatment of meteor physics, including the balance of frictional heating by radiative losses and the absorption of heat energy through temperature increases, melting phase transitions and vaporization, as well as sputtering by inelastic collisions with the air molecules. The vertical injection profiles are input into the Leeds 1-D Mars atmospheric model which includes photo-ionization, and gas-phase ion-molecule and neutral chemistry, in order to explore the evolution of the resulting metallic ions and atoms. We conclude that the dominant contributor in the Martian's atmosphere is the JFCs over other sources. Finally, we explore the changes of the neutral and ionized Na, Mg and Fe layers over a diurnal cycle.

  8. Innovative Techniques to Model, Analyze and Monitor Space Effects on Air Force Space-Based Systems

    DTIC Science & Technology

    2010-03-20

    of Comets in the Heliosphere as Observed by SMEI 4 2.8. Zodiacal Light Observations and Modeling 5 2.9. Space Weather Forecasting Lab (SWFL...This research resulted in two publications and a presentation at the 2007 American Geophysical Union Fall Meeting. 2.8. Zodiacal Light Observations...and Modeling One of the backgrounds removed from SMEI imagery is the scattered zodiacal light from solar system dust. The zodiacal light has

  9. Comparison of measured brightness temperatures from SMOS with modelled ones from ORCHIDEE and H-TESSEL over the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Barella-Ortiz, Anaïs; Polcher, Jan; de Rosnay, Patricia; Piles, Maria; Gelati, Emiliano

    2017-01-01

    L-band radiometry is considered to be one of the most suitable techniques to estimate surface soil moisture (SSM) by means of remote sensing. Brightness temperatures are key in this process, as they are the main input in the retrieval algorithm which yields SSM estimates. The work exposed compares brightness temperatures measured by the SMOS mission to two different sets of modelled ones, over the Iberian Peninsula from 2010 to 2012. The two modelled sets were estimated using a radiative transfer model and state variables from two land-surface models: (i) ORCHIDEE and (ii) H-TESSEL. The radiative transfer model used is the CMEM. Measured and modelled brightness temperatures show a good agreement in their temporal evolution, but their spatial structures are not consistent. An empirical orthogonal function analysis of the brightness temperature's error identifies a dominant structure over the south-west of the Iberian Peninsula which evolves during the year and is maximum in autumn and winter. Hypotheses concerning forcing-induced biases and assumptions made in the radiative transfer model are analysed to explain this inconsistency, but no candidate is found to be responsible for the weak spatial correlations at the moment. Further hypotheses are proposed and will be explored in a forthcoming paper. The analysis of spatial inconsistencies between modelled and measured TBs is important, as these can affect the estimation of geophysical variables and TB assimilation in operational models, as well as result in misleading validation studies.

  10. Effectiveness of angiotensin II receptor antagonists in a cohort of Dutch patients with type 2 diabetes mellitus (ZODIAC-14).

    PubMed

    van Hateren, Kornelis J J; Landman, Gijs W D; Groenier, Klaas H; Bilo, Henk J G; Kleefstra, Nanne

    2015-04-01

    There is limited evidence with respect to the between-group effects of various angiotensin receptor blockers (ARBs) on blood pressure and albuminuria in patients with type 2 diabetes mellitus. Therefore, we aimed to investigate the effects of differing ARBs on systolic blood pressure (SBP) and the albumin-creatinine ratio after 1 year in a large cohort of patients with type 2 diabetes mellitus. In 2007, 24 940 primary care patients with type 2 diabetes mellitus participated in the Zwolle Outpatient Diabetes project Integrating Available Care (ZODIAC) study, a prospective observational cohort study. Patients were included in the current study if they were prescribed an ARB in 2007 and if 1-year follow-up data were available. The final study population comprised 3610 patients. Multivariate mixed-model analyses were performed to estimate effects of the various ARBs on SBP and albuminuria. Stratified subgroup analyses were performed according to baseline hypertension and albuminuria. SBP decreased in all groups, the largest decrease being observed in the group receiving telmisartan. No significant or relevant changes over time were observed among groups for SBP and albuminuria. In the subgroup (n=1225) of normotensive patients, telmisartan was associated with a larger decrease in SBP after 1 year compared to other ARBs, without different effects on the albumin-creatinine ratio. We observed no differences in effects on SBP and the albumin-creatinine ratio among differing ARBs in patients with type 2 diabetes mellitus. Copyright © 2015 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.

  11. Addition of sulphonylurea to metformin does not relevantly change body weight: a prospective observational cohort study (ZODIAC-39).

    PubMed

    Schrijnders, Dennis; Wever, Raiza; Kleefstra, Nanne; Houweling, Sebastiaan T; van Hateren, Kornelis J J; de Bock, Geertruida H; Bilo, Henk J G; Groenier, Klaas H; Landman, Gijs W D

    2016-10-01

    To investigate changes in body weight trajectories after the addition of individual sulphonylureas (SUs) to metformin in patients with type 2 diabetes. We conducted a retrospective observational cohort study, in a primary care setting in the Netherlands. Patients aged ≥18 years with type 2 diabetes who were included in the ZODIAC cohort between 1998 and 2012 and who received metformin monotherapy at inclusion (n = 29 195), and had used metformin as monotherapy for at least 1 year before receiving dual therapy through the addition of an SU for at least 1 year were eligible for inclusion. The primary outcome was within-drug yearly change in body weight after receiving add-on therapy with individual SUs during 5 years of follow-up. The secondary outcome was within-drug yearly change in glycated haemoglobin (HbA1c). Annual changes in weight and HbA1c were estimated with linear mixed models, adjusted for age, gender and diabetes duration. A total of 2958 patients were included. No significant weight changes were observed within and between any of the individual SUs after treatment intensification (p = 0.24). In addition, no significant difference in weight between the add-on therapy combinations was observed (p = 0.26). The average HbA1c the year before intensification was 7.2% (55 mmol/mol) and dropped below 7.0% (53 mmol/mol) the year after. In patients with type 2 diabetes treated in primary care, strict glycaemic control can be maintained with SUs used as add-on therapy to metformin, without the offset of relevant weight changes. © 2016 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.

  12. Weak-Lensing Calibration of a Stellar Mass-Based Mass Proxy for redMaPPer and Voronoi Tessellation Clusters in SDSS Stripe 82

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pereira, Maria E.S.; Soares-Santos, Marcelle; Makler, Martin

    2017-08-10

    We present the first weak lensing calibration ofmore » $$\\mu_{\\star}$$, a new galaxy cluster mass proxy corresponding to the total stellar mass of red and blue members, in two cluster samples selected from the SDSS Stripe 82 data: 230 redMaPPer clusters at redshift $$0.1\\leq z<0.33$$ and 136 Voronoi Tessellation (VT) clusters at $$0.1 \\leq z < 0.6$$. We use the CS82 shear catalog and stack the clusters in $$\\mu_{\\star}$$ bins to measure a mass-observable power law relation. For redMaPPer clusters we obtain $$M_0 = (1.77 \\pm 0.36) \\times 10^{14}h^{-1} M_{\\odot}$$, $$\\alpha = 1.74 \\pm 0.62$$. For VT clusters, we find $$M_0 = (4.31 \\pm 0.89) \\times 10^{14}h^{-1} M_{\\odot}$$, $$\\alpha = 0.59 \\pm 0.54$$ and $$M_0 = (3.67 \\pm 0.56) \\times 10^{14}h^{-1} M_{\\odot}$$, $$\\alpha = 0.68 \\pm 0.49$$ for a low and a high redshift bin, respectively. Our results are consistent, internally and with the literature, indicating that our method can be applied to any cluster finding algorithm. In particular, we recommend that $$\\mu_{\\star}$$ be used as the mass proxy for VT clusters. Catalogs including $$\\mu_{\\star}$$ measurements will enable its use in studies of galaxy evolution in clusters and cluster cosmology.« less

  13. Weak-lensing calibration of a stellar mass-based mass proxy for redMaPPer and Voronoi Tessellation clusters in SDSS Stripe 82

    NASA Astrophysics Data System (ADS)

    Pereira, Maria E. S.; Soares-Santos, Marcelle; Makler, Martin; Annis, James; Lin, Huan; Palmese, Antonella; Vitorelli, André Z.; Welch, Brian; Caminha, Gabriel B.; Erben, Thomas; Moraes, Bruno; Shan, Huanyuan

    2018-02-01

    We present the first weak lensing calibration of μ⋆, a new galaxy cluster mass proxy corresponding to the total stellar mass of red and blue members, in two cluster samples selected from the SDSS Stripe 82 data: 230 red-sequence Matched-filter Probabilistic Percolation (redMaPPer) clusters at redshift 0.1 ≤ z < 0.33 and 136 Voronoi Tessellation (VT) clusters at 0.1 ≤ z < 0.6. We use the CS82 shear catalogue and stack the clusters in μ⋆ bins to measure a mass-observable power-law relation. For redMaPPer clusters we obtain M0 = (1.77 ± 0.36) × 1014 h-1M⊙, α = 1.74 ± 0.62. For VT clusters, we find M0 = (4.31 ± 0.89) × 1014 h-1M⊙, α = 0.59 ± 0.54 and M0 = (3.67 ± 0.56) × 1014 h-1M⊙, α = 0.68 ± 0.49 for a low and a high redshift bin, respectively. Our results are consistent, internally and with the literature, indicating that our method can be applied to any cluster-finding algorithm. In particular, we recommend that μ⋆ be used as the mass proxy for VT clusters. Catalogues including μ⋆ measurements will enable its use in studies of galaxy evolution in clusters and cluster cosmology.

  14. Radar detectability studies of slow and small Zodiacal Dust Cloud Particles: I. The case of Arecibo 430 MHz meteor head echo observations

    PubMed Central

    Janches, D.; Plane, J.M.C.; Nesvorný, D.; Feng, W.; Vokrouhlický, D.; Nicolls, M.J.

    2016-01-01

    Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorný et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth’s upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (~16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision. PMID:27642186

  15. Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles: I. The Case of Arecibo 430 MHz Meteor Head Echo Observations

    NASA Technical Reports Server (NTRS)

    Janches, D.; Plane, J. M. C.; Nesvorny, D.; Feng, W.; Vokrouhlicky, D.; Nicolls, M. J.

    2014-01-01

    Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorny et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth's upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (approximately 16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision.

  16. Radar detectability studies of slow and small zodiacal dust cloud particles. I. The case of Arecibo 430 MHz meteor head echo observations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Janches, D.; Plane, J. M. C.; Feng, W.

    2014-11-20

    Recent model development of the Zodiacal Dust Cloud (ZDC) argues that the incoming flux of meteoric material into the Earth's upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper, we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date.more » For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization, and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when (1) we invoke the lower limit of the model predicted flux (∼16 t d{sup –1}) and (2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high-speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones for low-speed meteors. However, even at this lower limit, the model overpredicts the slow portion of the Arecibo radial velocity distributions by a factor of three, suggesting that the model requires some revision.« less

  17. Velocity Distributions of Interplanetary Dust Derived from Astronomical Sky Spectra

    NASA Astrophysics Data System (ADS)

    Huestis, D. L.; Ali, S.; Cosby, P. C.; Slanger, T. G.

    2001-11-01

    Characterization of interplanetary dust is important for understanding the creation by accretion of planets and moons, the development of planetary atmospheres, and, potentially, for the initiation of prebiotic chemistry. The recent COBE mission has provided a profile in ecliptic coordinates of the distribution of interplanetary dust particles through their thermal infrared emission. Additional information about interplanetary dust can be extracted from its visible spectrum of scattered sunlight, called Zodiacal Light. Night sky spectra taken at large-aperture telescopes using high-resolution echelle spectrographs reveal Fraunhofer absorption features in the Zodiacal Light spectrum of scattered sunlight, a nuisance in subtraction from the spectrum of the extraterrestrial object under investigation. We are analyzing the intensity modulations and Doppler shifts of solar Fraunhofer absorption lines in the Zodiacal Light component of sky spectra, donated by collaborating astronomers using Keck/HIRES and other high-performance astronomical facilities. Our objectives include velocity distributions of interplanetary dust and improved separation of terrestrial and extraterrestrial sources in sky spectra. Participation of S. Ali was made possible by a grant from the NSF Physics Research Experiences for Undergraduates (REU) program.

  18. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhu, Yitan; Xu, Yanxun; Helseth, Donald L.

    Background: Genetic interactions play a critical role in cancer development. Existing knowledge about cancer genetic interactions is incomplete, especially lacking evidences derived from large-scale cancer genomics data. The Cancer Genome Atlas (TCGA) produces multimodal measurements across genomics and features of thousands of tumors, which provide an unprecedented opportunity to investigate the interplays of genes in cancer. Methods: We introduce Zodiac, a computational tool and resource to integrate existing knowledge about cancer genetic interactions with new information contained in TCGA data. It is an evolution of existing knowledge by treating it as a prior graph, integrating it with a likelihood modelmore » derived by Bayesian graphical model based on TCGA data, and producing a posterior graph as updated and data-enhanced knowledge. In short, Zodiac realizes “Prior interaction map + TCGA data → Posterior interaction map.” Results: Zodiac provides molecular interactions for about 200 million pairs of genes. All the results are generated from a big-data analysis and organized into a comprehensive database allowing customized search. In addition, Zodiac provides data processing and analysis tools that allow users to customize the prior networks and update the genetic pathways of their interest. Zodiac is publicly available at www.compgenome.org/ZODIAC. Conclusions: Zodiac recapitulates and extends existing knowledge of molecular interactions in cancer. It can be used to explore novel gene-gene interactions, transcriptional regulation, and other types of molecular interplays in cancer.« less

  19. Weak-lensing calibration of a stellar mass-based mass proxy for redMaPPer and Voronoi Tessellation clusters in SDSS Stripe 82

    DOE PAGES

    Pereira, Maria E. S.; Soares-Santos, Marcelle; Makler, Martin; ...

    2017-11-01

    Here, we present the first weak lensing calibration of μ*, a new galaxy cluster mass proxy corresponding to the total stellar mass of red and blue members, in two cluster samples selected from the SDSS Stripe 82 data: 230 red-sequence Matched-filter Probabilistic Percolation (redMaPPer) clusters at redshift 0.1 ≤ z < 0.33 and 136 Voronoi Tessellation (VT) clusters at 0.1 ≤ z < 0.6. We use the CS82 shear catalogue and stack the clusters in μ* bins to measure a mass-observable power-law relation. For redMaPPer clusters we obtain M0 = (1.77 ± 0.36) × 10 14 h –1M ⊙, αmore » = 1.74 ± 0.62. For VT clusters, we find M 0 = (4.31 ± 0.89) × 10 14 h –1M ⊙, α = 0.59 ± 0.54 and M0 = (3.67 ± 0.56) × 10 14 h –1M ⊙, α = 0.68 ± 0.49 for a low and a high redshift bin, respectively. Our results are consistent, internally and with the literature, indicating that our method can be applied to any cluster-finding algorithm. In particular, we recommend that μ* be used as the mass proxy for VT clusters. Catalogues including μ* measurements will enable its use in studies of galaxy evolution in clusters and cluster cosmology.« less

  20. Weak-lensing calibration of a stellar mass-based mass proxy for redMaPPer and Voronoi Tessellation clusters in SDSS Stripe 82

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pereira, Maria E. S.; Soares-Santos, Marcelle; Makler, Martin

    Here, we present the first weak lensing calibration of μ*, a new galaxy cluster mass proxy corresponding to the total stellar mass of red and blue members, in two cluster samples selected from the SDSS Stripe 82 data: 230 red-sequence Matched-filter Probabilistic Percolation (redMaPPer) clusters at redshift 0.1 ≤ z < 0.33 and 136 Voronoi Tessellation (VT) clusters at 0.1 ≤ z < 0.6. We use the CS82 shear catalogue and stack the clusters in μ* bins to measure a mass-observable power-law relation. For redMaPPer clusters we obtain M0 = (1.77 ± 0.36) × 10 14 h –1M ⊙, αmore » = 1.74 ± 0.62. For VT clusters, we find M 0 = (4.31 ± 0.89) × 10 14 h –1M ⊙, α = 0.59 ± 0.54 and M0 = (3.67 ± 0.56) × 10 14 h –1M ⊙, α = 0.68 ± 0.49 for a low and a high redshift bin, respectively. Our results are consistent, internally and with the literature, indicating that our method can be applied to any cluster-finding algorithm. In particular, we recommend that μ* be used as the mass proxy for VT clusters. Catalogues including μ* measurements will enable its use in studies of galaxy evolution in clusters and cluster cosmology.« less

  1. Improved Software Testing for Open Architecture

    DTIC Science & Technology

    2010-04-30

    2.5 4.2 28 7  Boston  Whaler  36  6.78 2.5 4 30 8  Zodiac   23  4.7  6.25  4.5  32  5  Wave Runner  44  3.66  6.25  4.4  47  15  The data in Table 1...30 April 2010 bu`bomq=colj=qeb Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is...estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining

  2. High-level Closed-loop Fusion and Decision Making with INFORM Lab

    DTIC Science & Technology

    2011-06-01

    gling fr eighte r zodiac Toolbox / Library node. The output of the editor is an XML file that contains all the information needed to run the ...surveillance. It uses two land-based zodiacs to offload the illegal immigrants, by making multiple trips to/from the freighter to ferry persons to the ...mapped in Figure 9. Figure 9 Map of Non-Cooperative Search Vignette The freighter and zodiacs will attempt various elusive manoeuvres depending on

  3. [Time-related aspects of suicides - suicide frequency related to birthday, major holidays, day of the week, season, month of birth and zodiac signs].

    PubMed

    Deisenhammer, Eberhard A; Stiglbauer, Christoph; Kemmler, Georg

    2018-06-01

    Suicides are generally the consequence of overchallenged coping strategies of individual for psychological, social or internal and external biological strain factors. Timing of the suicide, too, may be influenced by external factors. Studies so far have yielded in part inconsistent results concerning the association of suicides with particular days or periods of the year. Even less is known regarding a potential effect of the time of birth on suicide risk. The Tyrol Suicide Register (TSR) provides data on suicides occurring in the Austrian State of Tyrol including birthday of the suicide victim and day of the suicide. In the present study the frequency of suicides was analyzed with regard to birthday, day of the week, major holidays and season over a period of 17 years. Further, a potential association with month of birth and zodiac signs was studied. We found a significant variation in suicide frequency concerning day of the week with a peak on Mondays and Tuesdays and seasonality with increased numbers in spring and summer months. The increase of suicide numbers at the beginning of the week may be explained by the "broken-promise effect" which has been described as the consequence of frustrated expectations concerning the weekend. Possible explanations for the suicide peaks in spring and summer may be biological, specifically serotonergic alterations as well as the experience of depressed patients perceiving the social and emotional contrast to people who are able to enjoy these periods of pleasure and outdoor activities.

  4. Improving Neural Network Generalization Ability Using Outlier Analysis and Voronoi Tessellation

    NASA Technical Reports Server (NTRS)

    Ho, Michelle; McIntosh, Dawn M.; Srivastava, Ashok N.

    2006-01-01

    The data used in this study was obtained from the Sloan Digital Sky Survey (SDSS), which provides astronomers with what is currently the most extensive mapping of the universe, covering 25% of the sky and cataloging the spectral properties (e.g., luminosity, color, surface temperature) of over 100 million celestial objects. Images generated by the SDSS are collected through 5 filters named u, g, r, l, and z that have respective wavelengths of 3540, 4750, 6222, 7632, and 9049 A. By measuring the photometric redshifts of the aforementioned wavelengths of a galaxy, astronomers can ascertain the extent to which galaxy is receding from which the distance to the galaxy can be calculated. Data collected for a small select group of galaxies (approximately 30, 000) contains accurate measurements of the galaxies' redshifts, in addition to measurements of their spectral properties. The above dataset containing both redshift measurements as well as spectral properties of the selected galaxies served as the training set for the purposes of this study; the data set containing only the spectra properties of a separate group of galaxies served as the test set.

  5. Shock Mitigating Seat Single Impact Program

    DTIC Science & Technology

    2014-04-24

    new seats from Shockwave, SHOXS and Zodiac , were tested during the third and fourth phases of the final test program and these were conducted between...test program to the four single jockey style seats from Shockwave, SHOXS, Ullman and Zodiac because of budget and time constraints. The program...along with the Zodiac jockey pod seat that replaced the Ullman seat. 2711 (NETE CS) ZT4110-R 23 April 2014 QF035 32/39 Rev. 05/2011.11.14 69. The

  6. Detection of Subpixel Submerged Mine-Like Targets in WorldView-2 Multispectral Imagery

    DTIC Science & Technology

    2012-09-01

    and painted black, blue and green. The dot seen in the image by target three was a zodiac and it was only in the 21 March data set. 47 WorldView-2...region of interest (ROI) was created using band one of the covariance PCA image. The targets, buoy, and the zodiac were all considered targets. N...targets. Pixels that represented the zodiac were not segregated and found all over the visualization. For this reason, this process was followed by

  7. Sign of the Zodiac as a predictor of survival for recipients of an allogeneic stem cell transplant for chronic myeloid leukaemia (CML): an artificial association.

    PubMed

    Szydlo, R M; Gabriel, I; Olavarria, E; Apperley, J

    2010-10-01

    Astrological or Zodiac (star) sign has been shown to be a statistically significant factor in the outcome of a variety of diseases, conditions, and phenomena. To investigate its relevance in the context of a stem cell transplant (SCT), we examined its influence in chronic myeloid leukaemia, a disease with well-established prognostic factors. Data were collected on 626 patients who received a first myeloablative allogeneic SCT between 1981 and 2006. Star sign was determined for each patient. Univariate analyses comparing all 12 individual star signs showed considerable variation of 5-year probabilities of survival, 63% for Arians, to 45% for Aquarians, but without significance (P=.65). However, it was possible to pool together star signs likely to provide dichotomous results. Thus, grouping together Aries, Taurus, Gemini, Leo, Scorpio, and Capricorn (group A; n=317) versus others (group B; n=309) resulted in a highly significant difference (58% vs 48%; P=.007). When adjusted for known prognostic factors in a multivariate analysis, group B was associated with an increased risk of mortality when compared with group A (relative risk [RR], 1.37; P=.005). In this study, we show that, providing adequate care is taken, a significant relationship between patient star sign and survival post SCT for CML can be observed. This is, however, a completely erroneous result, and is based on the pooling together of observations to artificially create a statistically significant result. Statistical analyses should thus be carried out on a priori hypotheses and not to find a meaningful or significant result. Copyright © 2010 Elsevier Inc. All rights reserved.

  8. 78 FR 58965 - Airworthiness Directives; Bombardier, Inc. Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-25

    ... November 26, 2012. Zodiac Services has issued the following service bulletins. Zodiac Services Service... electrical status indications on the push button annunciators and the engine instrument and crew alerting system. Certain of those reported incidents resulted in the airplane experiencing a momentary loss of...

  9. Transmembrane protein PERP is a component of tessellate junctions and of other junctional and non-junctional plasma membrane regions in diverse epithelial and epithelium-derived cells.

    PubMed

    Franke, Werner W; Heid, Hans; Zimbelmann, Ralf; Kuhn, Caecilia; Winter-Simanowski, Stefanie; Dörflinger, Yvette; Grund, Christine; Rickelt, Steffen

    2013-07-01

    Protein PERP (p53 apoptosis effector related to PMP-22) is a small (21.4 kDa) transmembrane polypeptide with an amino acid sequence indicative of a tetraspanin character. It is enriched in the plasma membrane and apparently contributes to cell-cell contacts. Hitherto, it has been reported to be exclusively a component of desmosomes of some stratified epithelia. However, by using a series of newly generated mono- and polyclonal antibodies, we show that protein PERP is not only present in all kinds of stratified epithelia but also occurs in simple, columnar, complex and transitional epithelia, in various types of squamous metaplasia and epithelium-derived tumors, in diverse epithelium-derived cell cultures and in myocardial tissue. Immunofluorescence and immunoelectron microscopy allow us to localize PERP predominantly in small intradesmosomal locations and in variously sized, junction-like peri- and interdesmosomal regions ("tessellate junctions"), mostly in mosaic or amalgamated combinations with other molecules believed, to date, to be exclusive components of tight and adherens junctions. In the heart, PERP is a major component of the composite junctions of the intercalated disks connecting cardiomyocytes. Finally, protein PERP is a cobblestone-like general component of special plasma membrane regions such as the bile canaliculi of liver and subapical-to-lateral zones of diverse columnar epithelia and upper urothelial cell layers. We discuss possible organizational and architectonic functions of protein PERP and its potential value as an immunohistochemical diagnostic marker.

  10. Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles. III. The Role of Sodium and the Head Echo Size on the Probability of Detection

    NASA Astrophysics Data System (ADS)

    Janches, D.; Swarnalingam, N.; Carrillo-Sanchez, J. D.; Gomez-Martin, J. C.; Marshall, R.; Nesvorný, D.; Plane, J. M. C.; Feng, W.; Pokorný, P.

    2017-07-01

    We present a path forward on a long-standing issue concerning the flux of small and slow meteoroids, which are believed to be the dominant portion of the incoming meteoric mass flux into the Earth’s atmosphere. Such a flux, which is predicted by dynamical dust models of the Zodiacal Cloud, is not evident in ground-based radar observations. For decades this was attributed to the fact that the radars used for meteor observations lack the sensitivity to detect this population, due to the small amount of ionization produced by slow-velocity meteors. Such a hypothesis has been challenged by the introduction of meteor head echo (HE) observations with High Power and Large Aperture radars, in particular the Arecibo 430 MHz radar. Janches et al. developed a probabilistic approach to estimate the detectability of meteors by these radars and initially showed that, with the current knowledge of ablation and ionization, such particles should dominate the detected rates by one to two orders of magnitude compared to the actual observations. In this paper, we include results in our model from recently published laboratory measurements, which showed that (1) the ablation of Na is less intense covering a wider altitude range; and (2) the ionization probability, {β }{ip}, for Na atoms in the air is up to two orders of magnitude smaller for low speeds than originally believed. By applying these results and using a somewhat smaller size of the HE radar target we offer a solution that reconciles these observations with model predictions.

  11. Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles. III. The Role of Sodium and the Head Echo Size on the Probability of Detection

    NASA Technical Reports Server (NTRS)

    Janches, D.; Swarnalingam, N.; Carrillo-Sanchez, J. D.; Gomez-Martin, J. C.; Marshall, R.; Nesvorny, D.; Plane, J. M. C.; Feng, W.; Pokorny, P.

    2017-01-01

    We present a path forward on a long-standing issue concerning the flux of small and slow meteoroids, which are believed to be the dominant portion of the incoming meteoric mass flux into the Earth's atmosphere. Such a flux, which is predicted by dynamical dust models of the Zodiacal Cloud, is not evident in ground-based radar observations. For decades this was attributed to the fact that the radars used for meteor observations lack the sensitivity to detect this population, due to the small amount of ionization produced by slow-velocity meteors. Such a hypothesis has been challenged by the introduction of meteor head echo (HE) observations with High Power and Large Aperture radars, in particular the Arecibo 430 MHz radar. Janches et al. developed a probabilistic approach to estimate the detectability of meteors by these radars and initially showed that, with the current knowledge of ablation and ionization, such particles should dominate the detected rates by one to two orders of magnitude compared to the actual observations. In this paper, we include results in our model from recently published laboratory measurements, which showed that (1) the ablation of Na is less intense covering a wider altitude range; and (2) the ionization probability, Beta ip, for Na atoms in the air is up to two orders of magnitude smaller for low speeds than originally believed. By applying these results and using a somewhat smaller size of the HE radar target we offer a solution that reconciles these observations with model predictions.

  12. Effect of alcohols on the structure and dynamics of [BMIM][PF6] ionic liquid: A combined molecular dynamics simulation and Voronoi tessellation investigation

    NASA Astrophysics Data System (ADS)

    Sharma, Anirban; Ghorai, Pradip Kr.

    2018-05-01

    The solubility of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid (IL) in water is much less, whereas it is highly soluble in alcohol. The composition dependent structural and dynamical properties of [BMIM][PF6] in methanol and ethanol have been investigated by using all-atom molecular dynamics simulation. Though the density of IL/alcohol binary mixtures is nearly identical for different alcohol mole fractions, we observe the unalike structural and dynamical properties of the IL in methanol and ethanol due to different local environments of the IL and polarity of the solvent. Voronoi polyhedral analysis exhibits strong dependence of local environments on alcohol concentrations. Void and neck distribution in Voronoi tessellation are approximately Gaussian for pure IL, but it deviates from the Gaussian behavior at very high alcohol concentration. At low alcohol concentration, void and neck distributions of [BMIM]+ with [PF6]- in both methanol and ethanol are almost identical, whereas the distributions in ethanol are broader with lesser intensity than in methanol at high alcohol concentration. This suggests the existence of a very few larger free space in ethanol than in methanol. Although peak positions in the void and neck distributions in ethanol are at larger void and neck radius than in methanol, peak intensity for medium sized void in methanol is significantly higher than in ethanol. Thus the translational motion of both [BMIM]+ and [PF6]- and the rotational motion of [BMIM]+ are faster in methanol than in ethanol. Hydrogen bonding of [BMIM]+ with [PF6]- is more predominate than the alcohols, hence cation-anion hydrogen bonding plays an important role in determining self-diffusion coefficient (D) of [BMIM]+, whereas for [PF6]-, cooperative motion due to hydrogen bonding with the alcohols is indispensable.

  13. 76 FR 18020 - Airworthiness Directives; Sicma Aero Seat 9140, 9166, 9173, 9174, 9184, 9188, 9196, 91B7, 91B8...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-01

    ... [email protected]zodiac.com ; Internet http://www.sicma.zodiac.com/en/ . (3) You may review copies of the... adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory... identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as...

  14. Image and Processing Models for Satellite Detection in Images Acquired by Space-based Surveillance-of-Space Sensors

    DTIC Science & Technology

    2010-09-01

    external sources ‘L1’ like zodiacal light (or diffuse nebula ) or stray light ‘L2’ and these components change with the telescope pointing. Bk (T,t...Astronomical scene background (zodiacal light, diffuse nebulae , etc.). L2(P A(tk), t): Image background component caused by stray light. MS

  15. Investigating the importance of Delaunay-based definition of atomic interactions in scoring of protein-protein docking results.

    PubMed

    Jafari, Rahim; Sadeghi, Mehdi; Mirzaie, Mehdi

    2016-05-01

    The approaches taken to represent and describe structural features of the macromolecules are of major importance when developing computational methods for studying and predicting their structures and interactions. This study attempts to explore the significance of Delaunay tessellation for the definition of atomic interactions by evaluating its impact on the performance of scoring protein-protein docking prediction. Two sets of knowledge-based scoring potentials are extracted from a training dataset of native protein-protein complexes. The potential of the first set is derived using atomic interactions extracted from Delaunay tessellated structures. The potential of the second set is calculated conventionally, that is, using atom pairs whose interactions were determined by their separation distances. The scoring potentials were tested against two different docking decoy sets and their performances were compared. The results show that, if properly optimized, the Delaunay-based scoring potentials can achieve higher success rate than the usual scoring potentials. These results and the results of a previous study on the use of Delaunay-based potentials in protein fold recognition, all point to the fact that Delaunay tessellation of protein structure can provide a more realistic definition of atomic interaction, and therefore, if appropriately utilized, may be able to improve the accuracy of pair potentials. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. The Skylab ten color photoelectric polarimeter. [sky brightness

    NASA Technical Reports Server (NTRS)

    Weinberg, J. L.; Hahn, R. C.; Sparrow, J. G.

    1975-01-01

    A 10-color photoelectric polarimeter was used during Skylab missions SL-2 and SL-3 to measure sky brightness and polarization associated with zodiacal light, background starlight, and the spacecraft corona. A description is given of the instrument and observing routines together with initial results on the spacecraft corona and polarization of the zodiacal light.

  17. Origami Metamaterial based on Pattern Rigidity

    NASA Astrophysics Data System (ADS)

    Chen, Yan; You, Zhong

    Origami inspired mechanical metamaterials are made from a tessellation of origami units. Their mechanical behaviour is closely related to the behaviour of the origami units used. In this article, we focus on a family of metamaterials that are created by the tessellation of the square twist origami units. Generally a square twist origami unit can have four distinct hill-valley crease arrangements, two of which are rigidly foldable whereas the others are not. The rigidly foldable unit has, in general, lower stiffness than that of the non-rigidly foldable one if the facets can easily rotate about the creases. We shall show that it is possible to put rigidly foldable and non-rigidly foldable units together to form a geometrically compatible tessellation, and the stiffness of the overall structure based on such a tessellation is primarily decided by the number of non-rigid units. By astutely placing such units in a tessellation, we are able to create a metamaterial with a tunable stiffness. Y Chen acknowledges the support of the NSFC (Projects 51290293 and 51422506) and the Ministry of Science and Technology of China (Project 2014DFA70710). Z You wishes to acknowledge the support of Air Force Office of Scientific Research (FA9550-16-1-0339).

  18. An Empirical Decomposition of Near-IR Emission into Galactic and Extragalactic Components

    NASA Technical Reports Server (NTRS)

    Dwek, Eli; Arendt, Richard G.

    2002-01-01

    We decompose the COBE/DIRBE observations of the near-IR sky brightness (minus zodiacal light) into Galactic stellar and interstellar medium (ISM) components and an extragalactic background. This empirical procedure allows us to estimate the 4.9 micron cosmic infrared background (CIB) as a function of the CIB intensity at shorter wavelengths. A weak indication of a rising CIB intensity at wavelengths greater than 3.5$ microns hints at interesting astrophysics in the CIB spectrum, or warns that the foreground zodiacal emission may be incompletely subtracted. Subtraction of only the stellar component from the zodiacal-light-subtracted all--sky map reveals the clearest 3.5 micron ISM emission map, which is found to be tightly correlated with the ISM emission at far-IR wavelengths.

  19. History of the dust released by comets

    NASA Technical Reports Server (NTRS)

    Jambor, B. J.

    1976-01-01

    The Finson-Brobstein theory is used to examine production and history of dust released from periodic comets and to compare dust size distribution in relation to the Zodiacal cloud. Results eliminate all of the bright new comets from contributors to the Zodiacal cloud. Among the periodic comets, all particles of size much smaller than 10 micrometer are also lost. Only the large particles remain as possible contributors.

  20. Activities conducted during the definition phase of the outer planets missions program

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The activities are described of the Meteoroid Science Team for the definition phase of the outer planet missions. Studies reported include: (1) combined zodiacal experiment for the Grand Tour Missions of the outer planets, (2) optical transmission of a honeycomb panel and its effectiveness as a particle impact surface, (3) element identification data from the combined zodiacal OPGT experiment and (4) development of lightweight thermally stable mirrors.

  1. Polarization of the diffuse galactic light.

    NASA Technical Reports Server (NTRS)

    Sparrow, J. G.; Ney, E. P.

    1972-01-01

    Polarization measurements made from the satellite OSO-5 show that the polarized intensity in the direction of the Scutum arm of the Galaxy is different in intensity and direction of the polarization from that observed due to the zodiacal light. The observations are consistent with polarized diffuse galactic light superposed on the zodiacal light. The results are interpreted in terms of a model in which the galactic starlight is scattered by interstellar dust.

  2. Pair correlation functions for identifying spatial correlation in discrete domains

    NASA Astrophysics Data System (ADS)

    Gavagnin, Enrico; Owen, Jennifer P.; Yates, Christian A.

    2018-06-01

    Identifying and quantifying spatial correlation are important aspects of studying the collective behavior of multiagent systems. Pair correlation functions (PCFs) are powerful statistical tools that can provide qualitative and quantitative information about correlation between pairs of agents. Despite the numerous PCFs defined for off-lattice domains, only a few recent studies have considered a PCF for discrete domains. Our work extends the study of spatial correlation in discrete domains by defining a new set of PCFs using two natural and intuitive definitions of distance for a square lattice: the taxicab and uniform metric. We show how these PCFs improve upon previous attempts and compare between the quantitative data acquired. We also extend our definitions of the PCF to other types of regular tessellation that have not been studied before, including hexagonal, triangular, and cuboidal. Finally, we provide a comprehensive PCF for any tessellation and metric, allowing investigation of spatial correlation in irregular lattices for which recognizing correlation is less intuitive.

  3. Hatteras Breach, North Carolina

    DTIC Science & Technology

    2010-07-01

    1400 EST. Cross channel ADCP transects were also made from an instrumented Zodiac inflatable boat on 16, 17, and 24 October. The ADCP employed for...of the breach, near the middle, and on the sound side (Figure 11). The Zodiac crabbed (at an angle to the cur- rent) across the breach at a best...Coastal and Hydraulics Engineering Technical Note (CHETN) is intended to document the rapid response of the U.S. Army Corps of Engineers to engineer and

  4. On the Contribution of Asteroid Disruptions to the Interplanetary Dust Flux

    NASA Astrophysics Data System (ADS)

    Kehoe, T. J. J.; Kehoe, A. E.

    2017-12-01

    Recent modeling has shown the significant contribution of micron- to millimeter-sized particles released by the disruption of main-belt asteroids (MBAs) to the interplanetary dust particle (IDP) flux (e.g., Dermott et al., 2002; Nesvorný et al., 2003; Espy Kehoe et al., 2015). In this paper, we present the results of a study that indicates that the dust injected into the zodiacal cloud due to the catastrophic disruption of an asteroid is dominated by the release of its surface regolith particles. Our research suggests that disrupting a single asteroid with diameter O(100 km) will be enough to regenerate the entire zodiacal cloud. The breakup of smaller asteroids with diameters O(10 km) will likely produce more moderate, but still significant, changes in the dust environment of the inner solar system. As collisional disruptions of asteroids in this size range occur more frequently, it is important that we develop a better understanding of the injection of asteroidal material into the zodiacal cloud as a result of these type of events in order to determine the temporal evolution of the interplanetary dust flux. The results presented in this paper will lead to a better understanding of the threat to exploration activities due to the enhanced IDP flux resulting from the disruption of asteroidal regoliths. These findings can be employed to improve engineering models, for example, the NASA Meteoroid Engineering Model (MEM) that is widely utilized to assess the impact hazard to space hardware and activities in the inner solar system due to the natural meteoroid environment (McNamara et al., 2004). This is an important area of concern for current and future mission development purposes.

  5. Origami acoustics: using principles of folding structural acoustics for simple and large focusing of sound energy

    NASA Astrophysics Data System (ADS)

    Harne, Ryan L.; Lynd, Danielle T.

    2016-08-01

    Fixed in spatial distribution, arrays of planar, electromechanical acoustic transducers cannot adapt their wave energy focusing abilities unless each transducer is externally controlled, creating challenges for the implementation and portability of such beamforming systems. Recently, planar, origami-based structural tessellations are found to facilitate great versatility in system function and properties through kinematic folding. In this research we bridge the physics of acoustics and origami-based design to discover that the simple topological reconfigurations of a Miura-ori-based acoustic array yield many orders of magnitude worth of reversible change in wave energy focusing: a potential for acoustic field morphing easily obtained through deployable, tessellated architectures. Our experimental and theoretical studies directly translate the roles of folding the tessellated array to the adaptations in spectral and spatial wave propagation sensitivities for far field energy transmission. It is shown that kinematic folding rules and flat-foldable tessellated arrays collectively provide novel solutions to the long-standing challenges of conventional, electronically-steered acoustic beamformers. While our examples consider sound radiation from the foldable array in air, linear acoustic reciprocity dictates that the findings may inspire new innovations for acoustic receivers, e.g. adaptive sound absorbers and microphone arrays, as well as concepts that include water-borne waves.

  6. Representing Visibility for Siting Problems

    DTIC Science & Technology

    1994-04-01

    54 Figure 4.13 Alternative Tessellation of R2 Observations .............. 57 Figure 4.14 De -Cluttered Alternative Tessellation from R3 .......... .. 57...basis for a component of the next release of the TL%- AirLand Battle Environment (ALBE) software suite . TEC is also using algorithms developed as part...Considerations in LOS Calculation The details of calculating a LOS often receive relatively small mention in de - scriptions of visibility analyses but can have a

  7. Unstructured 3D Delaunay mesh generation applied to planes, trains and automobiles

    NASA Technical Reports Server (NTRS)

    Blake, Kenneth R.; Spragle, Gregory S.

    1993-01-01

    Technical issues associated with domain-tessellation production, including initial boundary node triangulation and volume mesh refinement, are presented for the 'TGrid' 3D Delaunay unstructured grid generation program. The approach employed is noted to be capable of preserving predefined triangular surface facets in the final tessellation. The capabilities of the approach are demonstrated by generating grids about an entire fighter aircraft configuration, a train, and a wind tunnel model of an automobile.

  8. Origins of the "Western" Constellations

    NASA Astrophysics Data System (ADS)

    Frank, Roslyn M.

    The development of the 48 Greek constellations is analyzed as a complex mixture of cognitive layers deriving from different cultural traditions and dating back to different epochs. The analysis begins with a discussion of the zodiacal constellations, goes on to discuss the stellar lore in Homer and Hesiod, and then examines several theories concerning the origins of the southern non-zodiacal constellations. It concludes with a commentary concerning the age and possible cultural significance of stars of the Great Bear constellation in light of ethnohistorical documentation, folklore, and beliefs related to European bear ceremonialism.

  9. Simulation of mixture microstructures via particle packing models and their direct comparison with real mixtures

    NASA Astrophysics Data System (ADS)

    Gulliver, Eric A.

    The objective of this thesis to identify and develop techniques providing direct comparison between simulated and real packed particle mixture microstructures containing submicron-sized particles. This entailed devising techniques for simulating powder mixtures, producing real mixtures with known powder characteristics, sectioning real mixtures, interrogating mixture cross-sections, evaluating and quantifying the mixture interrogation process and for comparing interrogation results between mixtures. A drop and roll-type particle-packing model was used to generate simulations of random mixtures. The simulated mixtures were then evaluated to establish that they were not segregated and free from gross defects. A powder processing protocol was established to provide real mixtures for direct comparison and for use in evaluating the simulation. The powder processing protocol was designed to minimize differences between measured particle size distributions and the particle size distributions in the mixture. A sectioning technique was developed that was capable of producing distortion free cross-sections of fine scale particulate mixtures. Tessellation analysis was used to interrogate mixture cross sections and statistical quality control charts were used to evaluate different types of tessellation analysis and to establish the importance of differences between simulated and real mixtures. The particle-packing program generated crescent shaped pores below large particles but realistic looking mixture microstructures otherwise. Focused ion beam milling was the only technique capable of sectioning particle compacts in a manner suitable for stereological analysis. Johnson-Mehl and Voronoi tessellation of the same cross-sections produced tessellation tiles with different the-area populations. Control charts analysis showed Johnson-Mehl tessellation measurements are superior to Voronoi tessellation measurements for detecting variations in mixture microstructure, such as altered

  10. Programming curvature using origami tessellations

    NASA Astrophysics Data System (ADS)

    Dudte, Levi H.; Vouga, Etienne; Tachi, Tomohiro; Mahadevan, L.

    2016-05-01

    Origami describes rules for creating folded structures from patterns on a flat sheet, but does not prescribe how patterns can be designed to fit target shapes. Here, starting from the simplest periodic origami pattern that yields one-degree-of-freedom collapsible structures--we show that scale-independent elementary geometric constructions and constrained optimization algorithms can be used to determine spatially modulated patterns that yield approximations to given surfaces of constant or varying curvature. Paper models confirm the feasibility of our calculations. We also assess the difficulty of realizing these geometric structures by quantifying the energetic barrier that separates the metastable flat and folded states. Moreover, we characterize the trade-off between the accuracy to which the pattern conforms to the target surface, and the effort associated with creating finer folds. Our approach enables the tailoring of origami patterns to drape complex surfaces independent of absolute scale, as well as the quantification of the energetic and material cost of doing so.

  11. Homogeneity and EPR metrics for assessment of regular grids used in CW EPR powder simulations.

    PubMed

    Crăciun, Cora

    2014-08-01

    CW EPR powder spectra may be approximated numerically using a spherical grid and a Voronoi tessellation-based cubature. For a given spin system, the quality of simulated EPR spectra depends on the grid type, size, and orientation in the molecular frame. In previous work, the grids used in CW EPR powder simulations have been compared mainly from geometric perspective. However, some grids with similar homogeneity degree generate different quality simulated spectra. This paper evaluates the grids from EPR perspective, by defining two metrics depending on the spin system characteristics and the grid Voronoi tessellation. The first metric determines if the grid points are EPR-centred in their Voronoi cells, based on the resonance magnetic field variations inside these cells. The second metric verifies if the adjacent Voronoi cells of the tessellation are EPR-overlapping, by computing the common range of their resonance magnetic field intervals. Beside a series of well known regular grids, the paper investigates a modified ZCW grid and a Fibonacci spherical code, which are new in the context of EPR simulations. For the investigated grids, the EPR metrics bring more information than the homogeneity quantities and are better related to the grids' EPR behaviour, for different spin system symmetries. The metrics' efficiency and limits are finally verified for grids generated from the initial ones, by using the original or magnetic field-constraint variants of the Spherical Centroidal Voronoi Tessellation method. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Analysis of IRAS solar system dust data

    NASA Technical Reports Server (NTRS)

    Dermott, S. F.; Nicholson, P. D.

    1991-01-01

    Data in the Infrared Astronomical Satellite (IRAS) Zodiacal History File were analyzed to extract dust band locations and peak brightness measurements from approximately 1,000 individual IRAS scans. The study had three goals. One was to show that the prominent solar system dust bands are associated with Hirayama asteroid families and thus that collisions between asteroids account for a significant fraction of the particles in the zodiacal cloud. Recent work suggests that while the Hirayama families are a major source of the dust in the bands, there may also be contributions from two or three smaller, more recently recognized asteroid families. A second goal was to show that there is evidence in the IRAS dust data for the transport of particles from asteroid belt to the Earth by Poynting-Robertson light drag and thus account for the fact that asteroid particles are collected in the Earth's stratosphere. Results of the study will confirm the location of the dust bands within the inner asteroid belt, and show conclusively that the material seen by IRAS is now spread over a wide range of distances from the sun. The third goal was to construct a model of the background zodiacal cloud that satisfies the proper dynamical constraints. Figures are provided to show the scans processed to remove zodiacal background and Galactic signals, and the resulting polynomial fits to the 25 micron scan. The latter provided objective estimates of band widths, peak locations, and peak fluxes. Modelling and analysis of the resulting band data has been presented at several conferences and is the subject of a number of forthcoming papers.

  13. Science of Time

    NASA Astrophysics Data System (ADS)

    Vedavyas

    A Multi-disciplinary Research into the Chronologies of Ancient Nations -- like the Vedas of India Rishies, the Chaldeans, Babylonians, Egyptians and the Chinese. Which traces how the "Measurement of Time" -- which began with the observations of sunrise and Sunset, Full-Moons, eclipses, the movement of stars and the Discovery of the Zodiac that starry pathway of sun in his annual Cycle of the 12-Zodiacal months, the Measurement of Time by planetary Cycles the Discovery of Astronomy and Symbolic or Kabalistic Astrology of the Bible's Old Testament; the Epics of Babylonians and 'Cosmic Cycles' of Chaldeans and Egyptians also the Ancient "Four Yugas" or Hindu Vedic Cycles.

  14. TESS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dmitriy Morozov, Tom Peterka

    2014-07-29

    Computing a Voronoi or Delaunay tessellation from a set of points is a core part of the analysis of many simulated and measured datasets. As the scale of simulations and observations surpasses billions of particles, a distributed-memory scalable parallel algorithm is the only feasible approach. The primary contribution of this software is a distributed-memory parallel Delaunay and Voronoi tessellation algorithm based on existing serial computational geometry libraries that automatically determines which neighbor points need to be exchanged among the subdomains of a spatial decomposition. Other contributions include the addition of periodic and wall boundary conditions.

  15. Sensitivity of the terrestrial planet finder

    NASA Technical Reports Server (NTRS)

    Beichman, Charles

    1998-01-01

    A key long-term goal of NASA's Origins program is the detection and characterization of habitable planets orbiting stars within the solar neighborhood. A cold, space-borne interferometer operating in the mid-infrared with a approx. 75 m baseline can null the light of a parent star and detect the million-times fainter radiation from an Earth-like planet located in the "habitable zone" around stars as far as 15 pc away. Such an interferometer, designated the Terrestrial Planet Finder (TPF) by NASA, could even detect atmospheric signatures of species such as CO2, O3, and H2O indicative of either the possibility or presence of primitive life. This talk highlights some of the sensitivity issues affecting the detectability of terrestrial planets. Sensitivity calculations show that a system consisting of 2 m apertures operating at 5 AU or 4 m apertures operating at 1 AU can detect terrestrial planets in reasonable integration times for levels of exo-zodiacal emission up to 10 times that seen in our solar system (hereafter denoted as 10xSS). Additionally, simulations show that confusion noise from structures in the exo-zodiacal cloud should not impede planet detection until the exo-zodiacal emission reaches the 10xSS level.

  16. Stochastic Seismic Inversion and Migration for Offshore Site Investigation in the Northern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Son, J.; Medina-Cetina, Z.

    2017-12-01

    We discuss the comparison between deterministic and stochastic optimization approaches to the nonlinear geophysical full-waveform inverse problem, based on the seismic survey data from Mississippi Canyon in the Northern Gulf of Mexico. Since the subsea engineering and offshore construction projects actively require reliable ground models from various site investigations, the primary goal of this study is to reconstruct the accurate subsurface information of the soil and rock material profiles under the seafloor. The shallow sediment layers have naturally formed heterogeneous formations which may cause unwanted marine landslides or foundation failures of underwater infrastructure. We chose the quasi-Newton and simulated annealing as deterministic and stochastic optimization algorithms respectively. Seismic forward modeling based on finite difference method with absorbing boundary condition implements the iterative simulations in the inverse modeling. We briefly report on numerical experiments using a synthetic data as an offshore ground model which contains shallow artificial target profiles of geomaterials under the seafloor. We apply the seismic migration processing and generate Voronoi tessellation on two-dimensional space-domain to improve the computational efficiency of the imaging stratigraphical velocity model reconstruction. We then report on the detail of a field data implementation, which shows the complex geologic structures in the Northern Gulf of Mexico. Lastly, we compare the new inverted image of subsurface site profiles in the space-domain with the previously processed seismic image in the time-domain at the same location. Overall, stochastic optimization for seismic inversion with migration and Voronoi tessellation show significant promise to improve the subsurface imaging of ground models and improve the computational efficiency required for the full waveform inversion. We anticipate that by improving the inversion process of shallow layers from

  17. Segmentation of heterogeneous blob objects through voting and level set formulation

    PubMed Central

    Chang, Hang; Yang, Qing; Parvin, Bahram

    2009-01-01

    Blob-like structures occur often in nature, where they aid in cueing and the pre-attentive process. These structures often overlap, form perceptual boundaries, and are heterogeneous in shape, size, and intensity. In this paper, voting, Voronoi tessellation, and level set methods are combined to delineate blob-like structures. Voting and subsequent Voronoi tessellation provide the initial condition and the boundary constraints for each blob, while curve evolution through level set formulation provides refined segmentation of each blob within the Voronoi region. The paper concludes with the application of the proposed method to a dataset produced from cell based fluorescence assays and stellar data. PMID:19774202

  18. Discovery of Prehistoric Skies

    NASA Astrophysics Data System (ADS)

    Gurshtein, A. A.

    1995-12-01

    It was Charles Francois Dupui, of France, who two centuries ago in his twelve-volume "Origine de tous les cults" (1795) worked out a proposition that all the different religious customs, stories, and dogmas will be found upon examination to have a cradle as one or another aspect of the natural, mainly, astronomical phenomena. It is absolutely correct but he and his spirited followers failed to develop a basic scientific quantitative argument focused on astronomy - chronological distribution of events. It is the first time that a combination of the up-to-date knowledge in archaic symbology and the professional astronomical data for precession and other regular astronomical events constitutes conditions for an absolutely new approach. An astronomical reconstruction of the evolution of the Zodiacal constellations was made, based on the Indo-european and Sumero-Akkadian religio-cultural data, including artifacts such as cult statuettes, cuneiform tablets, cylinder seals and boundary stones. It was argued that the development of 12 houses of the Zodiac in 3 groups of 4 over some six millennia was dictated by the changes made by precession in the positions of the vernal and autumnal equinoxes and the summer and winter solstices. The first quartet of the Zodiacal constellations (Gemini, Virgo, Sagittarius, Pisces) was recognized by the first agriculturists from the Fertile Crescent to learn the four most important Sun positions and to predict the ongoing seasons; it was done as far back as 5,600 B.C. (with a formal error of this determination about +/- 150 years). The second one (Taurus, Leo, Scorpio, Aquarius) was introduced in 2,700 +/- 250 years B.C. by Egyptians with their own animal symbolism that was the etymological root for the term the Zodiac (a circle of animals). This event was followed with the acquaintance of the new calendar and erection of the great pyramids as an eternal sanctuary for their mental triumph. In the first half of 14 century B.C. the Egyptian

  19. The finite body triangulation: algorithms, subgraphs, homogeneity estimation and application.

    PubMed

    Carson, Cantwell G; Levine, Jonathan S

    2016-09-01

    The concept of a finite body Dirichlet tessellation has been extended to that of a finite body Delaunay 'triangulation' to provide a more meaningful description of the spatial distribution of nonspherical secondary phase bodies in 2- and 3-dimensional images. A finite body triangulation (FBT) consists of a network of minimum edge-to-edge distances between adjacent objects in a microstructure. From this is also obtained the characteristic object chords formed by the intersection of the object boundary with the finite body tessellation. These two sets of distances form the basis of a parsimonious homogeneity estimation. The characteristics of the spatial distribution are then evaluated with respect to the distances between objects and the distances within them. Quantitative analysis shows that more physically representative distributions can be obtained by selecting subgraphs, such as the relative neighbourhood graph and the minimum spanning tree, from the finite body tessellation. To demonstrate their potential, we apply these methods to 3-dimensional X-ray computed tomographic images of foamed cement and their 2-dimensional cross sections. The Python computer code used to estimate the FBT is made available. Other applications for the algorithm - such as porous media transport and crack-tip propagation - are also discussed. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

  20. Contraction fracture: From 90° to 120° crack intersections

    NASA Astrophysics Data System (ADS)

    Lazarus, V.; Gauthier, G.; Pauchard, L.

    2009-12-01

    Giant's Causeway, Port Arthur tessellated pavement, Bimini Road, Mars polygons (whose presence indicated past occurrence of water), fracture networks in permafrost, septarias are some more or less known examples of self-organized crack patterns that have intrigued people through out history. Even now, they are sometimes attributed to legendary figures : Giant's, Atlantis mythical citizens. These pavements are in fact formed by constrained shrinking of the media due, for instance, to cooling or drying leading to fracture. The crack networks form mostly 90° or 120° angles. Here, we report experiments allowing to control the transition between 90° and 120°. We show that the transition is governed by the linear elastic fracture mechanics energy minimization principle, hence by two parameters: the cell size and the Griffith's length (minimum crack length beyond which the bulk energy is not sufficient to allow its propagation). This was achieved by measuring the Griffith's length directly on the same type of experiments by changing the cell geometry. Example of 90 degree and 120 crack intersections. Top-left : Giant's Causeway hexagonal tessellated pavement, Ireland (courtesy A. Davaille). Top-right: Port Arthur rectangular tessellated pavement, Tasmania (courtesy Wayne Bentley). Bottom : septarias (courtesy A. Rifki and M. Toussaint)

  1. TESS: A RELATIVISTIC HYDRODYNAMICS CODE ON A MOVING VORONOI MESH

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duffell, Paul C.; MacFadyen, Andrew I., E-mail: pcd233@nyu.edu, E-mail: macfadyen@nyu.edu

    2011-12-01

    We have generalized a method for the numerical solution of hyperbolic systems of equations using a dynamic Voronoi tessellation of the computational domain. The Voronoi tessellation is used to generate moving computational meshes for the solution of multidimensional systems of conservation laws in finite-volume form. The mesh-generating points are free to move with arbitrary velocity, with the choice of zero velocity resulting in an Eulerian formulation. Moving the points at the local fluid velocity makes the formulation effectively Lagrangian. We have written the TESS code to solve the equations of compressible hydrodynamics and magnetohydrodynamics for both relativistic and non-relativistic fluidsmore » on a dynamic Voronoi mesh. When run in Lagrangian mode, TESS is significantly less diffusive than fixed mesh codes and thus preserves contact discontinuities to high precision while also accurately capturing strong shock waves. TESS is written for Cartesian, spherical, and cylindrical coordinates and is modular so that auxiliary physics solvers are readily integrated into the TESS framework and so that this can be readily adapted to solve general systems of equations. We present results from a series of test problems to demonstrate the performance of TESS and to highlight some of the advantages of the dynamic tessellation method for solving challenging problems in astrophysical fluid dynamics.« less

  2. Polyhedra and Higher Dimensions.

    ERIC Educational Resources Information Center

    Scott, Paul

    1988-01-01

    Describes the definition and characteristics of a regular polyhedron, tessellation, and pseudopolyhedra with diagrams. Discusses the nature of simplex, hypercube, and cross-polytope in the fourth dimension and beyond. (YP)

  3. Commercial Mars Sample Return Architecture

    NASA Astrophysics Data System (ADS)

    Lenard, R.-X.

    2018-04-01

    Zodiac Planetary Services is a newly-formed company whose three founders together have over 80 years of space and high technology development and legal experience. The company uses IP created by the author covered by patent # 62/523432.

  4. Astrology

    NASA Astrophysics Data System (ADS)

    Pingree, D.; Murdin, P.

    2000-11-01

    Astrology is the theory that the planets, the Sun and the Moon, as well as the 12 `zodiacal signs', combine in various, ever-changing configurations with respect to each other and the local horizon to influence `sublunar' events....

  5. Resolution of the discrepancy between Balmer alpha emission rates, the solar Lyman beta flux, and models of geocoronal hydrogen concentration

    NASA Technical Reports Server (NTRS)

    Levasseur, A.-C.; Meier, R. R.; Tinsley, B. A.

    1976-01-01

    New satellite Balmer alpha measurements and solar Lyman beta flux and line profile measurements, together with new measurements of the zodiacal light intensity used in correcting both ground and satellite Balmer alpha measurements for the effects of the Fraunhofer line in the zodiacal light, have been used in a reevaluation of the long-standing discrepancy between ground-based Balmer alpha emission rates and other geocoronal hydrogen parameters. The solar Lyman beta line center flux is found to be (4.1 plus or minus 1.3) billion photons per sq cm per sec per angstrom at S(10.7) equals 110 and, together with a current hydrogen model which has 92,000 atoms per cu cm at 650 km for T(inf) equals 950 K, gives good agreement between calculated Balmer alpha emission rates and the ground-based and satellite measurements.

  6. Tessellating with Logo: Effects on Visual Literacy.

    ERIC Educational Resources Information Center

    Knupfer, Nancy Nelson; Clark, Barbara I.

    This investigation of the potential of a Logo environment to develop visual literacy skills in elementary school students focused on the recognition of Escher-type geometric constructions by second and sixth grade students. Four research questions were addressed: (1) whether students can use higher-order and creative thinking skills in using…

  7. Animals of the Chinese Zodiac. [Lesson Plan].

    ERIC Educational Resources Information Center

    2002

    The Chinese lunar calendar dates back to the second millennium BC. Unlike the western calendar, which numbers the years progressively from the birth of Jesus Christ, the Chinese calendar is cyclical. Each cycle is made up of 12 years--after the 12th year, the cycle is repeated. The Chinese associate each year of a 12-year cycle with an animal, and…

  8. Observations and Modelling of the Zodiacal Light

    NASA Astrophysics Data System (ADS)

    Kelsall, T.

    1994-12-01

    The DIRBE instrument on the COBE satellite performed a full-sky survey in ten bands covering the spectral range from 1.25 to 240 microns, and made measurements of the polarization from 1.25 to 3.5 microns. These observations provide a wealth of data on the radiations from the interplanetary dust cloud (IPD). The presentation covers the observations, the model-independent findings, and the results from the extensive efforts of the DIRBE team to model the IPD. Emphasis is placed on describing the importance of correctly accounting for the IPD contribution to the observed-sky signal for the purpose of detecting the cosmic infrared background. (*) The NASA/Goddard Space Flight Center (GSFC) is responsible for the design, development, and operation of the COBE mission. GSFC is also responsible for the development of the analysis software and for the production of the mission data sets. Scientific guidance is provided by the COBE Science Working Group. The COBE program is supported by the Astrophysics Division of NASA's Office of Space Science.

  9. The Astounding Stars.

    ERIC Educational Resources Information Center

    Montgomery, Angela; And Others

    1983-01-01

    Studying about stellar constellations provides children with an opportunity to learn about ancient myths and mathematics at the same time. An interdisciplinary teaching unit combines information about myths associated with the zodiac signs and instructions for plotting the coordinates of stars. (PP)

  10. Gemini Space Program emblem

    NASA Technical Reports Server (NTRS)

    1965-01-01

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

  11. Partition-based discrete-time quantum walks

    NASA Astrophysics Data System (ADS)

    Konno, Norio; Portugal, Renato; Sato, Iwao; Segawa, Etsuo

    2018-04-01

    We introduce a family of discrete-time quantum walks, called two-partition model, based on two equivalence-class partitions of the computational basis, which establish the notion of local dynamics. This family encompasses most versions of unitary discrete-time quantum walks driven by two local operators studied in literature, such as the coined model, Szegedy's model, and the 2-tessellable staggered model. We also analyze the connection of those models with the two-step coined model, which is driven by the square of the evolution operator of the standard discrete-time coined walk. We prove formally that the two-step coined model, an extension of Szegedy model for multigraphs, and the two-tessellable staggered model are unitarily equivalent. Then, selecting one specific model among those families is a matter of taste not generality.

  12. Observations of the diffuse near-UV radiation field

    NASA Technical Reports Server (NTRS)

    Murthy, J.; Henry, R. C.; Feldman, P. D.; Tennyson, P. D.

    1990-01-01

    The diffuse radiation field from 1650-3100 A has been observed by spectrometer aboard the Space Shuttle, and the contributions of the zodiacal light an the diffuse cosmic background to the signal have been derived. Colors ranging from 0.65 to 1.2 are found for the zodiacal light with an almost linear increase in the color with ecliptic latitude. This rise in color is due to UV brightness remaining almost constant while the visible brightnesses drop by almost a factor of two. This is interpreted as evidence that the grains responsible for the UV scattering have much more uniform distribution with distance from the ecliptic plane than do those grains responsible for the visible scattering. Intensities for the cosmic diffuse background ranging from 300 units to 900 units are found which are not consistent with either a correlation with N(H I) or with spatial isotropy.

  13. AS12-AS101-3 Breakthrough Capability for the NASA Astrophysics Explorer Program: Reaching the Darkest Sky

    NASA Technical Reports Server (NTRS)

    Greenhouse, Matthew; Benson, S.; Falck, R.; Fixsen, D.; Gardner, J.; Garvin, J.; Kruk, J.; Oleson, S.; Thronson, H.

    2011-01-01

    We describe a mission architecture designed to substantially increase the science capability of the NASA Science Mission Directorate (SMD) Astrophysics Explorer Program for all AO proposers working within the near-UV to far-infrared spectrum. We have demonstrated that augmentation of Falcon 9 Explorer launch services with a 13 kW Solar Electric Propulsion (SEP) stage can deliver a 700 kg science observatory payload to extra-Zodiacal orbit. Over the above wavelength range, observatory performance is limited by zodiacal light. This new capability enables up to 10X increased photometric sensitivity and 160X increased observing speed relative to a Sun-Earth L2, Earth-trailing, or Earth orbit with no increase in telescope aperture. All enabling SEP stage technologies for this launch service augmentation have reached sufficient readiness (TRl-6) for Explorer Program application in conjunction with the Falcon 9. We demonstrate that enabling Astrophysics Explorers to reach extra-zodiacal orbit will allow this small payload program to rival the Science performance of much larger long development time systems; thuS, providing a means to realize major science objectives while increasing the SMD Astrophysics portfolio diversity and resiliency to external budget pressure. The SEP technology employed in this study has strong applicability to SMD Planetary Science community-proposed missions and is a stated flight demonstration priority for NASA's Office of the Chief Technologist (OCT). This new mission architecture for astrophysics Explorers enables an attractive realization of joint goals for OCT and SMD with wide applicability across SMD science disciplines.

  14. Lessons learned in the conduct of a global, large simple trial of treatments indicated for schizophrenia.

    PubMed

    Kolitsopoulos, Francesca M; Strom, Brian L; Faich, Gerald; Eng, Sybil M; Kane, John M; Reynolds, Robert F

    2013-03-01

    Large, "practical" or streamlined trials (LSTs) are used to study the effectiveness and/or safety of medicines in real world settings with minimal study imposed interventions. While LSTs have benefits over traditional randomized clinical trials and observational studies, there are inherent challenges to their conduct. Enrollment and follow-up of a large study sample of patients with mental illness pose a particular difficulty. To assist in overcoming operational barriers in future LSTs in psychiatry, this paper describes the recruitment and observational follow-up strategies used for the ZODIAC study, an international, open-label LST, which followed 18,239 persons randomly assigned to one of two treatments indicated for schizophrenia for 1 year. ZODIAC enrolled patients in 18 countries in North America, South America, Europe, and Asia using broad study entry criteria and required minimal clinical care intervention. Recruitment of adequate numbers and continued engagement of both study centers and subjects were significant challenges. Strategies implemented to mitigate these in ZODIAC include global study expansion, study branding, field coordinator and site relations programs, monthly site newsletters, collection of alternate contact information, conduct of national death index (NDI) searches, and frequent sponsor, contract research organization (CRO) and site interaction to share best practices and address recruitment challenges quickly. We conclude that conduct of large LSTs in psychiatric patient populations is feasible, but importantly, realistic site recruitment goals and maintaining site engagement are key factors that need to be considered in early study planning and conduct. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Finish line distinctness and accuracy in 7 intraoral scanners versus conventional impression: an in vitro descriptive comparison.

    PubMed

    Nedelcu, Robert; Olsson, Pontus; Nyström, Ingela; Thor, Andreas

    2018-02-23

    Several studies have evaluated accuracy of intraoral scanners (IOS), but data is lacking regarding variations between IOS systems in the depiction of the critical finish line and the finish line accuracy. The aim of this study was to analyze the level of finish line distinctness (FLD), and finish line accuracy (FLA), in 7 intraoral scanners (IOS) and one conventional impression (IMPR). Furthermore, to assess parameters of resolution, tessellation, topography, and color. A dental model with a crown preparation including supra and subgingival finish line was reference-scanned with an industrial scanner (ATOS), and scanned with seven IOS: 3M, CS3500 and CS3600, DWIO, Omnicam, Planscan and Trios. An IMPR was taken and poured, and the model was scanned with a laboratory scanner. The ATOS scan was cropped at finish line and best-fit aligned for 3D Compare Analysis (Geomagic). Accuracy was visualized, and descriptive analysis was performed. All IOS, except Planscan, had comparable overall accuracy, however, FLD and FLA varied substantially. Trios presented the highest FLD, and with CS3600, the highest FLA. 3M, and DWIO had low overall FLD and low FLA in subgingival areas, whilst Planscan had overall low FLD and FLA, as well as lower general accuracy. IMPR presented high FLD, except in subgingival areas, and high FLA. Trios had the highest resolution by factor 1.6 to 3.1 among IOS, followed by IMPR, DWIO, Omnicam, CS3500, 3M, CS3600 and Planscan. Tessellation was found to be non-uniform except in 3M and DWIO. Topographic variation was found for 3M and Trios, with deviations below +/- 25 μm for Trios. Inclusion of color enhanced the identification of the finish line in Trios, Omnicam and CS3600, but not in Planscan. There were sizeable variations between IOS with both higher and lower FLD and FLA than IMPR. High FLD was more related to high localized finish line resolution and non-uniform tessellation, than to high overall resolution. Topography variations were low

  16. Topics

    ERIC Educational Resources Information Center

    Mathematics Teaching, 1972

    1972-01-01

    Topics discussed in this column include patterns of inverse multipliers in modular arithmetic; diagrams for product sets, set intersection, and set union; function notation; patterns in the number of partitions of positive integers; and tessellations. (DT)

  17. Advanced Concept

    NASA Image and Video Library

    2008-02-15

    Shown is the fabrication of the First Stage Main Parachute in support of Ares/CLV at the Pioneer Zodiac Facility in Mississippi in support of the Constellation/Ares project. This image is extracted from a high definition video file and is the highest resolution available

  18. Parachute Manufacturing

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Shown is the fabrication of the First Stage Main Parachute in support of Ares/CLV at the Pioneer Zodiac Facility in Mississippi in support of the Constellation/Ares project. This image is extracted from a high definition video file and is the highest resolution available

  19. A Feature-adaptive Subdivision Method for Real-time 3D Reconstruction of Repeated Topology Surfaces

    NASA Astrophysics Data System (ADS)

    Lin, Jinhua; Wang, Yanjie; Sun, Honghai

    2017-03-01

    It's well known that rendering for a large number of triangles with GPU hardware tessellation has made great progress. However, due to the fixed nature of GPU pipeline, many off-line methods that perform well can not meet the on-line requirements. In this paper, an optimized Feature-adaptive subdivision method is proposed, which is more suitable for reconstructing surfaces with repeated cusps or creases. An Octree primitive is established in irregular regions where there are the same sharp vertices or creases, this method can find the neighbor geometry information quickly. Because of having the same topology structure between Octree primitive and feature region, the Octree feature points can match the arbitrary vertices in feature region more precisely. In the meanwhile, the patches is re-encoded in the Octree primitive by using the breadth-first strategy, resulting in a meta-table which allows for real-time reconstruction by GPU hardware tessellation unit. There is only one feature region needed to be calculated under Octree primitive, other regions with the same repeated feature generate their own meta-table directly, the reconstruction time is saved greatly for this step. With regard to the meshes having a large number of repeated topology feature, our algorithm improves the subdivision time by 17.575% and increases the average frame drawing time by 0.2373 ms compared to the traditional FAS (Feature-adaptive Subdivision), at the same time the model can be reconstructed in a watertight manner.

  20. Recent Asteroid Disruptions in the WISE Dataset - Constraining Asteroid Surface Properties Using Solar System Dust Bands

    NASA Astrophysics Data System (ADS)

    Kehoe, A. E.; Shaw, C.; Kehoe, T. J. J.

    2017-12-01

    Zodiacal dust bands are a fine-structure feature of the mid-IR emission profile of the zodiacal cloud. The dust bands have been studied for many years dating back to the InfraRed Astronomical Satellite (IRAS) data of the 1980's. The recent discovery and modeling (Espy et al., 2009; 2010; Espy Kehoe et al., 2015) of a very young, still-forming dust band structure has shown that, in the early stages following an asteroid disruption, much information on the dust parameters of the original disruption is retained in the band. Partial dust bands allow a never-before-seen observational look at the size distribution and cross-sectional area of dust produced in an asteroidal disruption, before it has been lost or significantly altered by orbital and collisional decay. The study of these partial band structures reveals information on the way asteroids disrupt and allow us to reconstruct the surface properties of the parent asteroid, including the depth of the surface regolith and the size distribution of particles composing the regolith. Using the greatly increased sensitivity of the Wide-field Infrared Survey Explorer (WISE), we can now detect much fainter (and thus younger) dust bands. The WISE data also reveals much better longitudinal resolution of the bands, allowing a better constraint on the source and age of the disruption. We will present our newest results from the WISE dataset, including detection of faint partial dust bands, improved models of more prominent bands, and our constraints on the asteroid surface properties from modeling these structures.

  1. Serum peroxiredoxin 4: a marker of oxidative stress associated with mortality in type 2 diabetes (ZODIAC-28).

    PubMed

    Gerrits, Esther G; Alkhalaf, Alaa; Landman, Gijs W D; van Hateren, Kornelis J J; Groenier, Klaas H; Struck, Joachim; Schulte, Janin; Gans, Reinold O B; Bakker, Stephan J L; Kleefstra, Nanne; Bilo, Henk J G

    2014-01-01

    Oxidative stress plays an underlying pathophysiologic role in the development of diabetes complications. The aim of this study was to investigate peroxiredoxin 4 (Prx4), a proposed novel biomarker of oxidative stress, and its association with and capability as a biomarker in predicting (cardiovascular) mortality in type 2 diabetes mellitus. Prx4 was assessed in baseline serum samples of 1161 type 2 diabetes patients. Cox proportional hazard models were used to evaluate the relationship between Prx4 and (cardiovascular) mortality. Risk prediction capabilities of Prx4 for (cardiovascular) mortality were assessed with Harrell's C statistic, the integrated discrimination improvement and net reclassification improvement. Mean age was 67 and the median diabetes duration was 4.0 years. After a median follow-up period of 5.8 years, 327 patients died; 137 cardiovascular deaths. Prx4 was associated with (cardiovascular) mortality. The Cox proportional hazard models added the variables: Prx4 (model 1); age and gender (model 2), and BMI, creatinine, smoking, diabetes duration, systolic blood pressure, cholesterol-HDL ratio, history of macrovascular complications, and albuminuria (model 3). Hazard ratios (HR) (95% CI) for cardiovascular mortality were 1.93 (1.57 - 2.38), 1.75 (1.39 - 2.20), and 1.63 (1.28 - 2.09) for models 1, 2 and 3, respectively. HR for all-cause mortality were 1.73 (1.50 - 1.99), 1.50 (1.29 - 1.75), and 1.44 (1.23 - 1.67) for models 1, 2 and 3, respectively. Addition of Prx4 to the traditional risk factors slightly improved risk prediction of (cardiovascular) mortality. Prx4 is independently associated with (cardiovascular) mortality in type 2 diabetes patients. After addition of Prx4 to the traditional risk factors, there was a slightly improvement in risk prediction of (cardiovascular) mortality in this patient group.

  2. 75 FR 2826 - Airworthiness Directives; Sicma Aero Seat 88xx, 89xx, 90xx, 91xx, 92xx, 93xx, 95xx, and 96xx...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ....com ; Internet: http://www.sicma.zodiac.com/en/ . You may review copies of the referenced service... proposed rulemaking (NPRM). SUMMARY: We propose to adopt a new airworthiness directive (AD) for the... aviation product. The MCAI describes the unsafe condition as: Cracks have been found on seats [with...

  3. Stellar Symbols on Ancient Coins of the Roman Empire Part III: 193-235 AD

    NASA Astrophysics Data System (ADS)

    Rovithis-Livaniou, Eleni; Rovithis, Flora

    2017-10-01

    We continue to present and describe some ancient Roman coins with astronomical symbols like the Moon, the Zodiac signs, the stars, etc. The coins presented in this Paper correspond to the Roman Empire covering the interval (193 - 235) AD, which corresponds mainly to the Severan dynasty

  4. Component Fixturing Method

    NASA Technical Reports Server (NTRS)

    Kling, Daniel (Inventor)

    2014-01-01

    An end-configuration of components to be moved or positioned is first obtained. This end-configuration determines the relative positioning and orientation of the components with respect to each other when in a final, desired configuration. A folding pattern is then obtained that is formed by interior vertices defining corresponding tessellation facets. The folding pattern can be induced to transition from a first folded configuration to a second folded configuration. When in the second folded configuration mounting facets, which are a subset of the tessellation facets, are arranged by the geometry of the folding pattern into positions and orientations with respect to each other that correspond to the end-configuration of the components. A foldable structure is then obtained that folds in accordance with the folding pattern, and the components are affixed to their respective mounting facets.

  5. Contraction star-shaped cracks: From 90 degrees to 120 degrees crack intersections

    NASA Astrophysics Data System (ADS)

    Lazarus, Veronique; Gauthier, Georges

    2010-05-01

    Giant's Causeway, Port Arthur tessellated pavement, Bimini Road, Mars polygons, fracture networks in permafrost, septarias are some more or less known examples of self-organized crack patterns that have intrigued people through out history. These pavements are formed by constrained shrinking of the media due, for instance, to cooling or drying leading to fracture. The crack networks form in some conditions star-shaped cracks with mostly 90 or 120 degrees angles. Here, we report experiments allowing to control the transition between 90 and 120 degrees. We show that the transition is governed by the linear elastic fracture mechanics energy minimization principle, hence by two parameters: the cell size and the Griffith's length (balance between the energy needed to create cracks and to deform the material elastically). The results are used to infer new informations on tessellated pavements formation.

  6. Adaptive reconnection-based arbitrary Lagrangian Eulerian method

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bo, Wurigen; Shashkov, Mikhail

    We present a new adaptive Arbitrary Lagrangian Eulerian (ALE) method. This method is based on the reconnection-based ALE (ReALE) methodology of Refs. [35], [34] and [6]. The main elements in a standard ReALE method are: an explicit Lagrangian phase on an arbitrary polygonal (in 2D) mesh in which the solution and positions of grid nodes are updated; a rezoning phase in which a new grid is defined by changing the connectivity (using Voronoi tessellation) but not the number of cells; and a remapping phase in which the Lagrangian solution is transferred onto the new grid. Furthermore, in the standard ReALEmore » method, the rezoned mesh is smoothed by using one or several steps toward centroidal Voronoi tessellation, but it is not adapted to the solution in any way.« less

  7. Adaptive reconnection-based arbitrary Lagrangian Eulerian method

    DOE PAGES

    Bo, Wurigen; Shashkov, Mikhail

    2015-07-21

    We present a new adaptive Arbitrary Lagrangian Eulerian (ALE) method. This method is based on the reconnection-based ALE (ReALE) methodology of Refs. [35], [34] and [6]. The main elements in a standard ReALE method are: an explicit Lagrangian phase on an arbitrary polygonal (in 2D) mesh in which the solution and positions of grid nodes are updated; a rezoning phase in which a new grid is defined by changing the connectivity (using Voronoi tessellation) but not the number of cells; and a remapping phase in which the Lagrangian solution is transferred onto the new grid. Furthermore, in the standard ReALEmore » method, the rezoned mesh is smoothed by using one or several steps toward centroidal Voronoi tessellation, but it is not adapted to the solution in any way.« less

  8. Enrichment Activities for Geometry.

    ERIC Educational Resources Information Center

    Usiskin, Zalman

    1983-01-01

    Enrichment activities that teach about geometry as they instruct in geometry are given for some significant topics. The facets of geometry included are tessellations, round robin tournaments, geometric theorems on triangles, and connections between geometry and complex numbers. (MNS)

  9. Topics

    ERIC Educational Resources Information Center

    Mathematics Teaching, 1971

    1971-01-01

    Problems involving divisibility, the ten coin triangle, five times a week with 4 D, a nomogram for the lens formula, the box and ladder problem, chains of circles, tessellating hexagons, topological woggles, and numbers of triangles are discussed. (CT)

  10. Elastic transducers incorporating finite-length optical paths

    NASA Astrophysics Data System (ADS)

    Peters, Kara J.; Washabaugh, Peter D.

    1995-08-01

    Frequently, when designing a structure to incorporate integrated sensors, one sacrifices the stiffness of the system to improve sensitivity. However, the use of interferometric displacement sensors that tessellate throughout the volume of a structure has the potential to allow the precision and range of the component measurement to scale with the geometry of the device rather than the maximum strain in the structure. The design of stiff structures that measure all six resultant-load components is described. In addition, an advanced torsion sensor and a linear acceleration transducer are also discussed. Finally, invariant paths are presented that allow the in situ integrity of a structural volume to be monitored with a single pair of displacement sensors.

  11. Nonimaging polygonal mirrors achieving uniform irradiance distributions on concentrating photovoltaic cells.

    PubMed

    Schmitz, Max; Dähler, Fabian; Elvinger, François; Pedretti, Andrea; Steinfeld, Aldo

    2017-04-10

    We introduce a design methodology for nonimaging, single-reflection mirrors with polygonal inlet apertures that generate a uniform irradiance distribution on a polygonal outlet aperture, enabling a multitude of applications within the domain of concentrated photovoltaics. Notably, we present single-mirror concentrators of square and hexagonal perimeter that achieve very high irradiance uniformity on a square receiver at concentrations ranging from 100 to 1000 suns. These optical designs can be assembled in compound concentrators with maximized active area fraction by leveraging tessellation. More advanced multi-mirror concentrators, where each mirror individually illuminates the whole area of the receiver, allow for improved performance while permitting greater flexibility for the concentrator shape and robustness against partial shading of the inlet aperture.

  12. Subsurface Grain Morphology Reconstruction by Differential Aperture X-ray Microscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Eisenlohr, Philip; Shanthraj, Pratheek; Vande Kieft, Brendan R.

    A multistep, non-destructive grain morphology reconstruction methodology that is applicable to near-surface volumes is developed and tested on synthetic grain structures. This approach probes the subsurface crystal orientation using differential aperture x-ray microscopy on a sparse grid across the microstructure volume of interest. Resulting orientation data are clustered according to proximity in physical and orientation space and used as seed points for an initial Voronoi tessellation to (crudely) approximate the grain morphology. Curvature-driven grain boundary relaxation, simulated by means of the Voronoi implicit interface method, progressively improves the reconstruction accuracy. The similarity between bulk and readily accessible surface reconstruction errormore » provides an objective termination criterion for boundary relaxation.« less

  13. Subsurface Grain Morphology Reconstruction by Differential Aperture X-ray Microscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Eisenlohr, Philip; Shanthraj, Pratheek; Vande Kieft, Brendan R.

    A multistep, non-destructive grain morphology reconstruction methodology that is applicable to near-surface volumes is developed and tested on synthetic grain structures. This approach probes the subsurface crystal orientation using differential aperture X-ray microscopy (DAXM) on a sparse grid across the microstructure volume of interest. Resulting orientation data is clustered according to proximity in physical and orientation space and used as seed points for an initial Voronoi tessellation to (crudely) approximate the grain morphology. Curvature-driven grain boundary relaxation, simulated by means of the Voronoi Implicit Interface Method (VIIM), progressively improves the reconstruction accuracy. The similarity between bulk and readily accessible surfacemore » reconstruction error provides an objective termination criterion for boundary relaxation.« less

  14. February Folklore: You'll Love It in Your Curriculum.

    ERIC Educational Resources Information Center

    Gale, David

    1980-01-01

    Folk tales which are particularly suited to February cover legends about George Washington, the Chinese zodiac, and Groundhog Day. Also included is a calendar of activities for February. These activities are appropriate for Groundhog Day, Valentine's Day, Chinese New Year, President's (Washington and Lincoln) Day, and Leap Year. (KC)

  15. The cosmic infrared backgroung at 1.25 and 2.2 and microns using DIRBE and 2mass: a contribution not due to galaxies?

    NASA Technical Reports Server (NTRS)

    Cambresy, L.; Reach, W.; Beichman, C.; Jarrett, T.

    2001-01-01

    Using the 2MASS second incremental data release and the zodiacal subtracted mission average maps of COBE/DIRBE, the authors estimate the cosmic background in the J (1.25 mu m) and K (2.2 mu m) bands using selected areas representing 550 deg/sup 2/ of sky.

  16. Teaching Culture in a North American Context: The Chinese New Year.

    ERIC Educational Resources Information Center

    Luo, Cheng

    1994-01-01

    Addresses the need for a more balanced approach in teaching observable culture (music, letters, and arts) and nonobservable culture (belief, behavior, and values) associated with the second language learning process by looking at the celebration of the Chinese New Year. Topics discussed include the Chinese Zodiac, household preparations and social…

  17. Sky Glow from Cities: The Army Illumination Model v2

    DTIC Science & Technology

    2011-09-01

    magnetic field and is negligible. Zodiacal light is sunlight scattered by interplanetary dust and contributes up to half the brightness of the ...Sky Glow from Cities: The Army Illumination Model v2 by Richard C. Shirkey ARL-TR-5719 September 2011...Approved for public release; distribution is unlimited. NOTICES Disclaimers The

  18. 6. VIEW DESCENDING THE NORTH STAIRS OF THE HEADWALL, LEADING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW DESCENDING THE NORTH STAIRS OF THE HEADWALL, LEADING FROM THE EAST END OF FORECOURT TERRACE LEVEL TO THE LOWER LEVEL, AND DIRECTLY ONTO THE RADIAL PAVING OF COLORED MARBLE COBBLES ARRANGED TO REPRESENT THE TWELVE SIGNS OF THE ZODIAC - Kykuit, 200 Lake Road, Pocantico Hills, Westchester County, NY

  19. Using the 1989 Calendar as a Resource.

    ERIC Educational Resources Information Center

    Chick, Helen

    1989-01-01

    Presents 10 space-related ideas, thoughts, and questions represented on the Australian Association of Mathematics Teachers (AAMT) calendar. The ideas are on impossible shapes, fractals, space itself, galaxy, tesselated pigs, spirals, helices, black holes and three-dimensional surfaces, tesseracts, and mobius bands. (YP)

  20. Global-Scale P-Wave Tomography Designed for Accurate Prediction of Regional and Teleseismic Travel Times for Middle East Events

    DTIC Science & Technology

    2010-09-01

    latitude-longitude grid. Building a spherical tessellation mesh involves recursive subdivision of triangular facets of an initial polyhedron (in our...of our local database at Lawrence Livermore National Laboratory (Ruppert et al. 2005) and the publicly available Engdahl-van der Hilst-Buland (EHB

  1. Effects of spatial allocation and parameter variability on lakewide estimates from surveys of Lake Superior, North America’s largest lake

    EPA Science Inventory

    Lake Superior was sampled in 2011 using a Generalized Random Tessellation Stratified design (n=54 sites) to characterize biological and chemical properties of this huge aquatic resource, with statistical confidence. The lake was divided into two strata (inshore <100m and offsh...

  2. Spatial Resolution, Grayscale, and Error Diffusion Trade-offs: Impact on Display System Design

    NASA Technical Reports Server (NTRS)

    Gille, Jennifer L. (Principal Investigator)

    1996-01-01

    We examine technology trade-offs related to grayscale resolution, spatial resolution, and error diffusion for tessellated display systems. We present new empirical results from our psychophysical study of these trade-offs and compare them to the predictions of a model of human vision.

  3. Structural characterization of the packings of granular regular polygons.

    PubMed

    Wang, Chuncheng; Dong, Kejun; Yu, Aibing

    2015-12-01

    By using a recently developed method for discrete modeling of nonspherical particles, we simulate the random packings of granular regular polygons with three to 11 edges under gravity. The effects of shape and friction on the packing structures are investigated by various structural parameters, including packing fraction, the radial distribution function, coordination number, Voronoi tessellation, and bond-orientational order. We find that packing fraction is generally higher for geometrically nonfrustrated regular polygons, and can be increased by the increase of edge number and decrease of friction. The changes of packing fraction are linked with those of the microstructures, such as the variations of the translational and orientational orders and local configurations. In particular, the free areas of Voronoi tessellations (which are related to local packing fractions) can be described by log-normal distributions for all polygons. The quantitative analyses establish a clearer picture for the packings of regular polygons.

  4. Rules of tissue packing involving different cell types: human muscle organization

    PubMed Central

    Sánchez-Gutiérrez, Daniel; Sáez, Aurora; Gómez-Gálvez, Pedro; Paradas, Carmen; Escudero, Luis M.

    2017-01-01

    Natural packed tissues are assembled as tessellations of polygonal cells. These include skeletal muscles and epithelial sheets. Skeletal muscles appear as a mosaic composed of two different types of cells: the “slow” and “fast” fibres. Their relative distribution is important for the muscle function but little is known about how the fibre arrangement is established and maintained. In this work we capture the organizational pattern in two different healthy muscles: biceps brachii and quadriceps. Here we show that the biceps brachii muscle presents a particular arrangement, based on the different sizes of slow and fast fibres. By contrast, in the quadriceps muscle an unbiased distribution exists. Our results indicate that the relative size of each cellular type imposes an intrinsic organization into natural tessellations. These findings establish a new framework for the analysis of any packed tissue where two or more cell types exist. PMID:28071729

  5. Rules of tissue packing involving different cell types: human muscle organization.

    PubMed

    Sánchez-Gutiérrez, Daniel; Sáez, Aurora; Gómez-Gálvez, Pedro; Paradas, Carmen; Escudero, Luis M

    2017-01-10

    Natural packed tissues are assembled as tessellations of polygonal cells. These include skeletal muscles and epithelial sheets. Skeletal muscles appear as a mosaic composed of two different types of cells: the "slow" and "fast" fibres. Their relative distribution is important for the muscle function but little is known about how the fibre arrangement is established and maintained. In this work we capture the organizational pattern in two different healthy muscles: biceps brachii and quadriceps. Here we show that the biceps brachii muscle presents a particular arrangement, based on the different sizes of slow and fast fibres. By contrast, in the quadriceps muscle an unbiased distribution exists. Our results indicate that the relative size of each cellular type imposes an intrinsic organization into natural tessellations. These findings establish a new framework for the analysis of any packed tissue where two or more cell types exist.

  6. 76 FR 22830 - Airworthiness Directives; Sicma Aero Seat 88xx, 89xx, 90xx, 91xx, 92xx, 93xx, 95xx, and 96xx...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-25

    ... ; Internet http://www.sicma.zodiac.com/en/ . You may review copies of the referenced service information at... earlier NPRM for the products listed above. This action revises the earlier NPRM by expanding the scope.... The MCAI describes the unsafe condition as: Cracks have been found on seats [with] backrest links P/N...

  7. Experiment requirements document for reflight of the small helium-cooled infrared telescope experiment

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The four astronomical objectives addressed include: the measurement and mapping of extended low surface brightness infrared emission from the galaxy; the measurement of diffuse emission from intergalactic material and/or galaxies and quasi-stellar objects; the measurement of the zodiacal dust emission; and the measurement of a large number of discrete infrared sources.

  8. Size Dependence of Dust Distribution around the Earth Orbit

    NASA Astrophysics Data System (ADS)

    Ueda, Takahiro; Kobayashi, Hiroshi; Takeuchi, Taku; Ishihara, Daisuke; Kondo, Toru; Kaneda, Hidehiro

    2017-05-01

    In the solar system, interplanetary dust particles (IDPs) originating mainly from asteroid collisions and cometary activities drift to Earth orbit due to Poynting-Robertson drag. We analyzed the thermal emission from IDPs that was observed by the first Japanese infrared astronomical satellite, AKARI. The observed surface brightness in the trailing direction of the Earth orbit is 3.7% greater than that in the leading direction in the 9 μm band and 3.0% in the 18 μm band. In order to reveal dust properties causing leading-trailing surface brightness asymmetry, we numerically integrated orbits of the Sun, the Earth, and a dust particle as a restricted three-body problem including radiation from the Sun. The initial orbits of particles are determined according to the orbits of main-belt asteroids or Jupiter-family comets. Orbital trapping in mean motion resonances results in a significant leading-trailing asymmetry so that intermediate sized dust (˜10-100 μm) produces a greater asymmetry than zodiacal light. The leading-trailing surface brightness difference integrated over the size distribution of the asteroidal dust is obtained to be 27.7% and 25.3% in the 9 μm and 18 μm bands, respectively. In contrast, the brightness difference for cometary dust is calculated as 3.6% and 3.1% in the 9 μm and 18 μm bands, respectively, if the maximum dust radius is set to be s max = 3000 μm. Taking into account these values and their errors, we conclude that the contribution of asteroidal dust to the zodiacal infrared emission is less than ˜10%, while cometary dust of the order of 1 mm mainly accounts for the zodiacal light in infrared.

  9. Alien Asteroid Belt Compared to our Own

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: Band of Light Comparison

    This artist's concept illustrates what the night sky might look like from a hypothetical alien planet in a star system with an asteroid belt 25 times as massive as the one in our own solar system (alien system above, ours below; see Figure 1).

    NASA's Spitzer Space Telescope found evidence for such a belt around the nearby star called HD 69830, when its infrared eyes spotted dust, presumably from asteroids banging together. The telescope did not find any evidence for a planet in the system, but astronomers speculate one or more may be present.

    The movie begins at dusk on the imaginary world, when HD 69830, like our Sun, has begun to set over the horizon. Time is sped up to show the onset of night and the appearance of a brilliant band of light. This light comes from dust in a massive asteroid belt, which scatters sunlight.

    In our solar system, anybody observing the skies on a moonless night far from city lights can see the sunlight that is scattered by dust in our asteroid belt. Called zodiacal light and sometimes the 'false dawn,' this light appears as a dim band stretching up from the horizon when the Sun is about to rise or set. The light is faint enough that the disk of our Milky Way galaxy remains the most prominent feature in the sky. (The Milky Way disk is shown perpendicular to the zodiacal light in both pictures.)

    In contrast, the zodiacal light in the HD 69830 system would be 1,000 times brighter than our own, outshining even the Milky Way.

  10. Size Dependence of Dust Distribution around the Earth Orbit

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ueda, Takahiro; Takeuchi, Taku; Kobayashi, Hiroshi

    In the solar system, interplanetary dust particles (IDPs) originating mainly from asteroid collisions and cometary activities drift to Earth orbit due to Poynting–Robertson drag. We analyzed the thermal emission from IDPs that was observed by the first Japanese infrared astronomical satellite, AKARI . The observed surface brightness in the trailing direction of the Earth orbit is 3.7% greater than that in the leading direction in the 9 μ m band and 3.0% in the 18 μ m band. In order to reveal dust properties causing leading–trailing surface brightness asymmetry, we numerically integrated orbits of the Sun, the Earth, and amore » dust particle as a restricted three-body problem including radiation from the Sun. The initial orbits of particles are determined according to the orbits of main-belt asteroids or Jupiter-family comets. Orbital trapping in mean motion resonances results in a significant leading–trailing asymmetry so that intermediate sized dust (∼10–100 μ m) produces a greater asymmetry than zodiacal light. The leading–trailing surface brightness difference integrated over the size distribution of the asteroidal dust is obtained to be 27.7% and 25.3% in the 9 μ m and 18 μ m bands, respectively. In contrast, the brightness difference for cometary dust is calculated as 3.6% and 3.1% in the 9 μ m and 18 μ m bands, respectively, if the maximum dust radius is set to be s {sub max} = 3000 μ m. Taking into account these values and their errors, we conclude that the contribution of asteroidal dust to the zodiacal infrared emission is less than ∼10%, while cometary dust of the order of 1 mm mainly accounts for the zodiacal light in infrared.« less

  11. 77 FR 39186 - Airworthiness Directives; Airbus Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-02

    [email protected]zodiac.com ; Internet http://www.zodiacaerospace.com . You may review copies of the referenced service... A321 series airplanes. This proposed AD was prompted by reports of the escape slide of the raft inflation system not deploying when activated due to the rotation of the cable guide in a direction which...

  12. A new sampling scheme for tropical forest monitoring using satellite imagery

    Treesearch

    Frederic Achard; Tim Richards; Javier Gallego

    2000-01-01

    At the global level, a sampling scheme for tropical forest change assessment, using high resolution satellite images, has been defined using sampling units independent of any particular satellite sensor. For this purpose, a sampling frame has been chosen a hexagonal tessellation of 3,600 km².

  13. The performance of approximations of farm contiguity compared to contiguity defined using detailed geographical information in two sample areas in Scotland: implications for foot-and-mouth disease modelling.

    PubMed

    Flood, Jessica S; Porphyre, Thibaud; Tildesley, Michael J; Woolhouse, Mark E J

    2013-10-08

    When modelling infectious diseases, accurately capturing the pattern of dissemination through space is key to providing optimal recommendations for control. Mathematical models of disease spread in livestock, such as for foot-and-mouth disease (FMD), have done this by incorporating a transmission kernel which describes the decay in transmission rate with increasing Euclidean distance from an infected premises (IP). However, this assumes a homogenous landscape, and is based on the distance between point locations of farms. Indeed, underlying the spatial pattern of spread are the contact networks involved in transmission. Accordingly, area-weighted tessellation around farm point locations has been used to approximate field-contiguity and simulate the effect of contiguous premises (CP) culling for FMD. Here, geographic data were used to determine contiguity based on distance between premises' fields and presence of landscape features for two sample areas in Scotland. Sensitivity, positive predictive value, and the True Skill Statistic (TSS) were calculated to determine how point distance measures and area-weighted tessellation compared to the 'gold standard' of the map-based measures in identifying CPs. In addition, the mean degree and density of the different contact networks were calculated. Utilising point distances <1 km and <5 km as a measure for contiguity resulted in poor discrimination between map-based CPs/non-CPs (TSS 0.279-0.344 and 0.385-0.400, respectively). Point distance <1 km missed a high proportion of map-based CPs; <5 km point distance picked up a high proportion of map-based non-CPs as CPs. Area-weighted tessellation performed best, with reasonable discrimination between map-based CPs/non-CPs (TSS 0.617-0.737) and comparable mean degree and density. Landscape features altered network properties considerably when taken into account. The farming landscape is not homogeneous. Basing contiguity on geographic locations of field boundaries and including

  14. Exozodiacal Dust Workshop

    NASA Technical Reports Server (NTRS)

    Backman, D. E. (Editor); Caroff, L. J. (Editor); Sandford, S. A. (Editor); Wooden, D. H. (Editor)

    1998-01-01

    The purpose of the workshop was to understand what effect circumstellar dust clouds will have on NASA's proposed Terrestrial Planet Finder (TPF) mission's ability to search for terrestrial-sized planets orbiting stars in the solar neighborhood. The workshop participants reviewed the properties of TPF, summarized what is known about the local zodiacal cloud and about exozodiacal clouds, and determined what additional knowledge must be obtained to help design TPF for maximum effectiveness within its cost constraint. Recommendations were made for ways to obtain that additional knowledge, at minimum cost. The workshop brought together approximately 70 scientists, from four different countries. The active participants included astronomers involved in the study of the local zodiacal cloud, in the formation of stars and planetary systems, and in the technologies and techniques of ground- and space-based infrared interferometry. During the course of the meeting, 15 invited talks and 20 contributed poster papers were presented, and there were four working sessions. This is a collection of the invited talks, contributed poster papers, and summaries of the working sessions.

  15. The cosmic infrared background experiment (CIBER): instrumentation and first results

    NASA Astrophysics Data System (ADS)

    Zemcov, M.; Battle, J.; Bock, J.; Cooray, A.; Hristov, V.; Keating, B.; Lee, D. H.; Levenson, L.; Mason, P.; Matsumoto, T.; Matsuura, S.; Nam, U. W.; Renbarger, T.; Sullivan, I.; Tsumura, K.; Wada, T.

    2010-07-01

    Ultraviolet emission from the first generation of stars in the Universe ionized the intergalactic medium in a process which was completed by z ~ 6; the wavelength of these photons has been redshifted by (1 + z) into the near infrared today and can be measured using instruments situated above the Earth's atmosphere. First flying in February 2009, the Cosmic Infrared Background ExpeRiment (CIBER) comprises four instruments housed in a single reusable sounding rocket borne payload. CIBER will measure spatial anisotropies in the extragalactic IR background caused by cosmological structure from the epoch of reionization using two broadband imaging instruments, make a detailed characterization of the spectral shape of the IR background using a low resolution spectrometer, and measure the absolute brightness of the Zodiacal light foreground with a high resolution spectrometer in each of our six science fields. The scientific motivation for CIBER and details of its first and second flight instrumentation will be discussed. First flight results on the color of the zodiacal light around 1 μm and plans for the future will also be presented.

  16. Interplanetary dust. [survey of last four years' research

    NASA Technical Reports Server (NTRS)

    Brownlee, D. E.

    1979-01-01

    Progress in the study of interplanetary dust during the past four years is reviewed. Attention is given to determinations of the relative contributions of interstellar dust grains, collisional debris from the asteroid belt and short-period comets to the interplanetary dust cloud. Effects of radiation pressure and collisions on particle dynamics are discussed, noting the discovery of the variation of the orbital parameters of dust particles at 1 AU with size and in situ measurements of dust density between 0.3 and 5 AU by the Helios and Pioneer spacecraft. The interpretation of the zodiacal light as produced by porous absorbing particles 10 to 100 microns in size is noted, and measurements of the Doppler shift, light-producing-particle density, UV spectrum, photometric axis and angular scattering function of the zodiacal light are reported. Results of analyses of lunar rock microcraters as to micrometeoroid density, flux rate, size distribution and composition are indicated and interplanetary dust particles collected from the stratosphere are discussed. Findings concerning the composition of fragile meteoroid types found as cosmic spherules in deep sea sediments are also presented.

  17. Efficient isoparametric integration over arbitrary space-filling Voronoi polyhedra for electronic structure calculations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Alam, Aftab; Khan, S. N.; Wilson, Brian G.

    2011-07-06

    A numerically efficient, accurate, and easily implemented integration scheme over convex Voronoi polyhedra (VP) is presented for use in ab initio electronic-structure calculations. We combine a weighted Voronoi tessellation with isoparametric integration via Gauss-Legendre quadratures to provide rapidly convergent VP integrals for a variety of integrands, including those with a Coulomb singularity. We showcase the capability of our approach by first applying it to an analytic charge-density model achieving machine-precision accuracy with expected convergence properties in milliseconds. For contrast, we compare our results to those using shape-functions and show our approach is greater than 10 5 times faster and 10more » 7 times more accurate. Furthermore, a weighted Voronoi tessellation also allows for a physics-based partitioning of space that guarantees convex, space-filling VP while reflecting accurate atomic size and site charges, as we show within KKR methods applied to Fe-Pd alloys.« less

  18. A Teacher's Activities Guide for Chinese New Year - Gung Hei Fat Choy.

    ERIC Educational Resources Information Center

    Sonoma County Superintendent of Schools, Santa Rosa, CA.

    This teacher's guide is designed to provide information and activities on the Chinese New Year and on aspects of the culture and heritage of the Chinese-American. Background material is given on the history of Chinese immigration to America, the lunar calendar, the Chinese cycle of years, the Chinese zodiac, the philosophical concept of yin and…

  19. Nephrology and astrology--is there a link?

    PubMed

    Hughes, S

    1990-07-01

    Astrologers presume a link between the susceptibility of particular organs to disease and signs of the Zodiac. A simple test of the positive connection between renal disease and the sign of Libra was undertaken by studying the birth dates of consecutive nephrology in-patient admissions. No significant link was found on analysis, thus disproving the traditional astrologers' claims.

  20. Apollo 17 ultraviolet spectrometer experiment (S-169)

    NASA Technical Reports Server (NTRS)

    Fastie, W. G.

    1974-01-01

    The scientific objectives of the ultraviolet spectrometer experiment are discussed, along with design and operational details, instrument preparation and performance, and scientific results. Information gained from the experiment is given concerning the lunar atmosphere and albedo, zodiacal light, astronomical observations, spacecraft environment, and the distribution of atomic hydrogen in the solar system and in the earth's atmosphere.

  1. Leo

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Lion; abbrev. Leo, gen. Leonis; area 947 sq. deg.) A northern zodiacal constellation which lies between Cancer and Virgo, and culminates at midnight in early March. It represents the Nemean lion that, in Greek mythology, Hercules killed as the first of his 12 labors. Its brightest stars were cataloged by Ptolemy (c. AD 100-175) in the Almagest....

  2. Allium To Zircon: Mathematics and Nature.

    ERIC Educational Resources Information Center

    Harrell, Marvin E.; Fosnaugh, Linda S.

    1997-01-01

    Discusses how nature can illustrate mathematical structures and concepts in the classroom. For example, the upper surface of a typical leaf structure illustrates the notion of tessellating with polygons. Also lists classroom applications and hands-on activities such as growing crystals to investigate the natural forms of polyhedra and measuring…

  3. Application of Differential Evolutionary Optimization Methodology for Parameter Structure Identification in Groundwater Modeling

    NASA Astrophysics Data System (ADS)

    Chiu, Y.; Nishikawa, T.

    2013-12-01

    With the increasing complexity of parameter-structure identification (PSI) in groundwater modeling, there is a need for robust, fast, and accurate optimizers in the groundwater-hydrology field. For this work, PSI is defined as identifying parameter dimension, structure, and value. In this study, Voronoi tessellation and differential evolution (DE) are used to solve the optimal PSI problem. Voronoi tessellation is used for automatic parameterization, whereby stepwise regression and the error covariance matrix are used to determine the optimal parameter dimension. DE is a novel global optimizer that can be used to solve nonlinear, nondifferentiable, and multimodal optimization problems. It can be viewed as an improved version of genetic algorithms and employs a simple cycle of mutation, crossover, and selection operations. DE is used to estimate the optimal parameter structure and its associated values. A synthetic numerical experiment of continuous hydraulic conductivity distribution was conducted to demonstrate the proposed methodology. The results indicate that DE can identify the global optimum effectively and efficiently. A sensitivity analysis of the control parameters (i.e., the population size, mutation scaling factor, crossover rate, and mutation schemes) was performed to examine their influence on the objective function. The proposed DE was then applied to solve a complex parameter-estimation problem for a small desert groundwater basin in Southern California. Hydraulic conductivity, specific yield, specific storage, fault conductance, and recharge components were estimated simultaneously. Comparison of DE and a traditional gradient-based approach (PEST) shows DE to be more robust and efficient. The results of this work not only provide an alternative for PSI in groundwater models, but also extend DE applications towards solving complex, regional-scale water management optimization problems.

  4. Revisiting the finite temperature string method for the calculation of reaction tubes and free energies

    NASA Astrophysics Data System (ADS)

    Vanden-Eijnden, Eric; Venturoli, Maddalena

    2009-05-01

    An improved and simplified version of the finite temperature string (FTS) method [W. E, W. Ren, and E. Vanden-Eijnden, J. Phys. Chem. B 109, 6688 (2005)] is proposed. Like the original approach, the new method is a scheme to calculate the principal curves associated with the Boltzmann-Gibbs probability distribution of the system, i.e., the curves which are such that their intersection with the hyperplanes perpendicular to themselves coincides with the expected position of the system in these planes (where perpendicular is understood with respect to the appropriate metric). Unlike more standard paths such as the minimum energy path or the minimum free energy path, the location of the principal curve depends on global features of the energy or the free energy landscapes and thereby may remain appropriate in situations where the landscape is rough on the thermal energy scale and/or entropic effects related to the width of the reaction channels matter. Instead of using constrained sampling in hyperplanes as in the original FTS, the new method calculates the principal curve via sampling in the Voronoi tessellation whose generating points are the discretization points along this curve. As shown here, this modification results in greater algorithmic simplicity. As a by-product, it also gives the free energy associated with the Voronoi tessellation. The new method can be applied both in the original Cartesian space of the system or in a set of collective variables. We illustrate FTS on test-case examples and apply it to the study of conformational transitions of the nitrogen regulatory protein C receiver domain using an elastic network model and to the isomerization of solvated alanine dipeptide.

  5. Ophiuchus

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Serpent-bearer; abbrev. Oph, gen. Ophiuchi; area 948 sq. deg.) An equatorial constellation which lies between Hercules and Scorpius, and culminates at midnight in mid-June. The ecliptic cuts across the southern part of Ophiuchus, but the constellation is not included among the constellations of the zodiac. Ophiuchus is usually said to represent Asclepius, the Greek god of medicine, and is sh...

  6. The Time of Grand Strategy

    DTIC Science & Technology

    2013-03-01

    representations of Chronos illustrate this combination: the god of time is either portrayed pushing the zodiac wheel,6 illustrating the rotation of seasons... The Time of Grand Strategy by Lieutenant-Colonel Arnaud Goujon French Army United States Army War...College Class of 2013 DISTRIBUTION STATEMENT: A Approved for Public Release Distribution is Unlimited COPYRIGHT STATEMENT: The author is not an

  7. Variations in Gegenschein polarization

    NASA Technical Reports Server (NTRS)

    Sparrow, J. G.; Weinberg, J. L.

    1975-01-01

    Claims made by Bandermann and Wolstencroft (1974) that angular structure and day-to-day variations of the polarized component of the zodiacal light were observed near the antisolar point are shown to be unsubstantiated. The data obtained by Bandermann and Wolstencroft are reviewed together with the instruments they used. It is shown that the incorrect results reported were due to observation errors.

  8. Lunar and Planetary Science XXXVI, Part 9

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The following topics were discussed: Monitoring floods with NASA's ST6 autonomous spacecraft experiment; Dynamical cloud models constrained by high resolution spectroscopy of zodiacal light; The oxygen isotopic composition of the sun and implications for oxygen processing in molecular clouds; A nochian/hisperian hiatus and erosive reactivation of martian valley networks; Hard x-ray spectro-microscopy techniques; Thermoluminescence studies of carbonaceous chondrites, etc.

  9. Birkeland, Kristian (1868-1917)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2001-07-01

    Birkeland was a Norwegian physicist, born in Oslo. In 1900, he identified and then simulated the charged electron-magnetic flux tube connection between the Sun and Earth that produces the aurora. He studied the zodiacal light during expeditions to the Sudan and Egypt. Birkeland committed suicide in a depression associated with the rejection of his auroral theories by his contemporary established...

  10. Creativity and Motivation for Geometric Tasks Designing in Education

    ERIC Educational Resources Information Center

    Rumanová, Lucia; Smiešková, Edita

    2015-01-01

    In this paper we focus on creativity needed for geometric tasks designing, visualization of geometric problems and use of ICT. We present some examples of various problems related to tessellations. Altogether 21 students--pre-service teachers participated in our activity within a geometry course at CPU in Nitra, Slovakia. Our attempt was to…

  11. IDE spatio-temporal impact fluxes and high time-resolution studies of multi-impact events and long-lived debris clouds

    NASA Technical Reports Server (NTRS)

    Mulholland, J. Derral; Singer, S. Fred; Oliver, John P.; Weinberg, Jerry L.; Cooke, William J.; Montague, Nancy L.; Wortman, Jim J.; Kassel, Phillip C.; Kinard, William H.

    1992-01-01

    The purpose of the Interplanetary Dust Experiment (IDE) on the Long Duration Exposure Facility (LDEF) was to sample the cosmic dust environment and to use the spatio-temporal aspect of the experiment to distinguish between the various components of the environment: zodiacal cloud, beta meteoroids, meteor streams, interstellar dust, and orbital debris. It was found that the introduction of precise time and even rudimentary directionality as co-lateral observables in sampling the particulate environment in near-Earth space produces an enormous qualitative improvement in the information content of the impact data. The orbital debris population is extremely clumpy, being dominated by persistent clouds in which the fluxes may rise orders of magnitude above the background. The IDE data suggest a strategy to minimize the damage to sensitive spacecraft components, using the observed characteristics of cloud encounters.

  12. Origins and Dynamics of Interplanetary Dust Particles

    NASA Technical Reports Server (NTRS)

    Dermott, Stanley F.

    2005-01-01

    This is a final report for research supported by the National Aeronautics and Space Administration issued through the Office of Space Science Planetary Geology and Geophysics Program, covering all relevant activities during its 3-year period of funding from 02/01/2002 through to 01/31/2005. The ongoing aim of the research supported through this grant, and now through a successor award, is to investigate the origin of interplanetary dust particles (IDPs) and their dynamical and collisional evolution, in order to: (1) understand the provenance of zodiacal cloud particles and their transport from their source regions to the inner solar system; (2) produce detailed models of the zodiacal cloud and its constituent components; (3) determine the origin of the dust particles accreted by the Earth; (4) ascertain the level of temporal variations in the dust environment of the inner solar system and the accretion rate of IDPs by the Earth, and evaluate potential effects on global climate; and to (5) exploit this research as a basis for interpreting the structure observed in exozodiacal clouds that may result from the collisional evolution of planetesimals and the presence of unseen planets.

  13. A quest for 2D lattice materials for actuation

    NASA Astrophysics Data System (ADS)

    Pronk, T. N.; Ayas, C.; Tekõglu, C.

    2017-08-01

    In the last two decades, most of the studies in shape morphing technology have focused on the Kagome lattice materials, which have superior properties such as in-plane isotropy, high specific stiffness and strength, and low energy requirement for actuation of its members. The Kagome lattice is a member of the family of semi-regular tessellations of the plane. Two fundamental questions naturally arise: i-) What makes a lattice material suitable for actuation? ii-) Are there other tessellations more effective than the Kagome lattice for actuation? The present paper tackles both questions, and provides a clear answer to the first one by comparing an alternative lattice material, the hexagonal cupola, with the Kagome lattice in terms of mechanical/actuation properties. The second question remains open, but, hopefully easier to challenge owing to a newly-discovered criterion: for an n-dimensional (n = 2 , 3) in-plane isotropic lattice material to be suitable for actuation, its pin-jointed equivalent must obey the generalised Maxwell's rule, and must possess M = 3(n - 1) non strain-producing finite kinematic mechanisms.

  14. Olbers, Heinrich Wilhelm (1758-1840)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Doctor, astronomer, born in Arbergen, Germany, enthusiast for astronomy. He discovered several comets. In 1800 he joined the team of 24 `celestial police', organized by FRANZ VON ZACH, who were to patrol a share of the zodiac looking for the planet missing (according to BODE's law) between Mars and Jupiter. On New Year's Day 1801 PIAZZI discovered Ceres, and, in March 1802, Olbers discovered Pall...

  15. Divided Instruments

    NASA Astrophysics Data System (ADS)

    Chapman, A.; Murdin, P.

    2000-11-01

    Although the division of the zodiac into 360° probably derives from Egypt or Assyria around 2000 BC, there is no surviving evidence of Mesopotamian cultures embodying this division into a mathematical instrument. Almost certainly, however, it was from Babylonia that the Greek geometers learned of the 360° circle, and by c. 80 BC they had incorporated it into that remarkably elaborate device gener...

  16. Israel’s Blockade of Gaza, the Mavi Marmara Incident, and Its Aftermath

    DTIC Science & Technology

    2010-06-16

    navy zodiac boats intercepted them and naval commandos took over five ships, reportedly without incident. However, the Marmara resisted and...CRS Report for Congress Prepared for Members and Committees of Congress Israel’s Blockade of Gaza, the Mavi Marmara Incident, and Its...Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response

  17. Future Missions to Study Signposts of Planets

    NASA Technical Reports Server (NTRS)

    Traub, Wesley A.

    2011-01-01

    This talk will focus on debris disks, will compare ground and space and will discuss 2 proposed missions, Exoplanetary Circumstellar Environments And Disk Explorer (EXCEDE) and Zodiac II. At least 2 missions have been proposed for disk imaging. The technology is largely in hand today. A small mission would do excellent disk science, and would test technology for a future large mission for planets.

  18. Managing Network Security Policies in Tactical Manet’s Using Drama

    DTIC Science & Technology

    2010-08-04

    Cheng, M. Raykova, A. Poylisher, S. Alexander, M. Eiger, S. M. Bellovin, “ The Zodiac Policy Subsystem: A Policy-Based Management System for a High...hour per response, including the time for reviewing instructions, searching data sources, gathering and maintaining the data needed, and completing and...reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information

  19. Naval Sea Systems Command On Watch 2010

    DTIC Science & Technology

    2010-01-01

    surface targets, such as zodiacs and fast patrol boats found in the littoral environment. As for future capabilities and goals for the program, An...Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour...per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing

  20. Maritime Mass Rescue Interventions: Availability and Associated Technology

    DTIC Science & Technology

    2010-12-01

    MOR Liferaft Description: The Zodiac MOR (Means of Rescue) was specially developed to meet the latest requirements introduced for Roll On/Roll Off...Mass Rescue Interventions; Availability and Associated Technology NOTICE This document is disseminated under the sponsorship of the Department of...Homeland Security in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof. The

  1. The Astral Curved Disc of Chevroches (France)

    NASA Astrophysics Data System (ADS)

    Devevey, F. Rousseau, A.

    2009-08-01

    The excavation of the unexplored secondary agglomeration in Chevroches (Nièvre), from 2001 to 2002, directed by F. Devevey (INRAP), has led to the discovery of an astrological bronze curved disc of a type unknown in the ancient world; it is inscribed with three lines in Greek transcribing Egyptian an Roman months, and the twelve signs of the zodiac. This article presents the first observations.

  2. Late Babylonian Astrology

    NASA Astrophysics Data System (ADS)

    Steele, John M.

    The last five centuries BC saw the development of several new forms of astrology in Babylonia. Key to these new astrological techniques was the invention of the zodiac in about 400 BC. These new forms of astrology include personal horoscopes, astral medicine, and the exploitation of geometrical relationships between the position of heavenly bodies. Several Late Babylonian astrological doctrines were later adopted within Greek astrology.

  3. Pisces

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Fishes; abbrev. Psc, gen. Piscium; area 889 sq. deg.) A northern zodiacal constellation which lies between Pegasus and Cetus, and culminates at midnight in late September. Its origin dates back to Babylonian times and it is said to represent Aphrodite, the goddess of love in Greek mythology, and her son Eros, who jumped into the Euphrates to escape from the multi-headed Typhon and were turned...

  4. Scorpius

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Scorpion; abbrev. Sco., gen. Scorpii; area 497 sq. deg.) A southern zodiacal constellation which lies between Ophiuchus and Ara, and culminates at midnight in early June. Its origin dates back to Sumerian times, when it was called Girtab, `the stinger', but today it is associated with the scorpion that, in Greek mythology, killed Orion the hunter—and the two constellations lie on opposite sid...

  5. Aquarius

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Water-bearer; abbrev. Aqr, gen. Aquarii; area 980 sq. deg.) A southern zodiacal constellation that lies between Pegasus and Piscis Austrinus, and culminates at midnight in late August. Its origin dates back to Babylonian times and it is said to represent Ganymede in Greek mythology, who was snatched up by Aquila (the eagle) on Zeus's behest, to become cup-bearer to the gods. Its brightest st...

  6. Gemini

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

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

  7. Capricornus

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Sea Goat; abbrev. Cap, gen. Capricorni; area 414 sq. deg.) A southern zodiacal constellation which lies between Sagittarius and Aquarius, and culminates at midnight in early August. The origin of the unusual constellation figure, which comprises the head and forelimbs of a goat and tail of a fish, dates back to Babylonian times and has also been associated in Greek mythology with Pan, who ha...

  8. Cancer

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Crab; abbrev. Cnc, genitive Cancri; area 506 sq. deg.) A northern zodiacal constellation which lies between Gemini and Leo, and culminates at midnight in late January. It represents the crab that, in Greek mythology, Hercules crushed underfoot during his fight with the multi-headed Hydra. The name of α Cancri, its brightest star, is Acubens, which comes from the Arabic word meaning `the claw...

  9. Dynamics of satellites, asteroids, and rings

    NASA Technical Reports Server (NTRS)

    Dermott, Stanley F.

    1987-01-01

    Work is reported on: (1) the shapes and the internal structures of satellites; (2) the tidal heating of Miranda; (3) the dynamics of arc-like rings; and (4) the structure of the zodiacal cloud that was revealed by the Infrared Astronomy Satellite. Significant progress was made in determining the shape and internal structure of Mimas and in understanding the dynamical evolution of Miranda's orbit.

  10. Constrained map-based inventory estimation

    Treesearch

    Paul C. Van Deusen; Francis A. Roesch

    2007-01-01

    A region can conceptually be tessellated into polygons at different scales or resolutions. Likewise, samples can be taken from the region to determine the value of a polygon variable for each scale. Sampled polygons can be used to estimate values for other polygons at the same scale. However, estimates should be compatible across the different scales. Estimates are...

  11. Geoff Giles and Geometry

    ERIC Educational Resources Information Center

    Fielker, David

    2007-01-01

    Geoff Giles died suddenly in 2005. He was a highly original thinker in the field of geometry teaching. As early as 1964, when teaching at Strathallen School in Perth, he was writing in "MT27" about constructing tessellations by modifying the sides of triangles and (irregular) quadrilaterals to produce what he called "trisides" and "quadrisides".…

  12. PLATO, APOLLONIUS, AND KLEIN:. Playing with Spheres

    NASA Astrophysics Data System (ADS)

    Mantica, Giorgio

    We show that a large class of circle packings can be generated by combining hyperbolic and spherical (or Euclidean) tessellation groups. We provide the general group-theoretical framework associated to an efficient, geometrically inspired, construction of these packings. We classify the different packings that can be obtained in this way, and we investigate their fractal properties.

  13. Use of Novel Surfaces to Reduce Bioadhesion on Infrastructure

    DTIC Science & Technology

    2010-06-01

    Research and Development Center Model species selection • Terrestrial gastropod  Danger to crops  Intermediate host to pathogens  Nocturnal...TBT  Non-target species, legacy contamination  Laborious • Bio-inspiration: leverage biological surfaces that have adapted unique properties... Adapted over 1000s of years • Hypothesis: microstructured pattern tessellations, hydrophobicity, surface properties or hybridizations will reduce

  14. Towards a Full-sky, High-resolution Dust Extinction Map with WISE and Planck

    NASA Astrophysics Data System (ADS)

    Meisner, Aaron M.; Finkbeiner, D. P.

    2014-01-01

    We have recently completed a custom processing of the entire WISE 12 micron All-sky imaging data set. The result is a full-sky map of diffuse, mid-infrared Galactic dust emission with angular resolution of 15 arcseconds, and with contaminating artifacts such as compact sources removed. At the same time, the 2013 Planck HFI maps represent a complementary data set in the far-infrared, with zero-point relatively immune to zodiacal contamination and angular resolution superior to previous full-sky data sets at similar frequencies. Taken together, these WISE and Planck data products present an opportunity to improve upon the SFD (1998) dust extinction map, by virtue of enhanced angular resolution and potentially better-controlled systematics on large scales. We describe our continuing efforts to construct and test high-resolution dust extinction and temperature maps based on our custom WISE processing and Planck HFI data.

  15. Alignment of large image series using cubic B-splines tessellation: application to transmission electron microscopy data.

    PubMed

    Dauguet, Julien; Bock, Davi; Reid, R Clay; Warfield, Simon K

    2007-01-01

    3D reconstruction from serial 2D microscopy images depends on non-linear alignment of serial sections. For some structures, such as the neuronal circuitry of the brain, very large images at very high resolution are necessary to permit reconstruction. These very large images prevent the direct use of classical registration methods. We propose in this work a method to deal with the non-linear alignment of arbitrarily large 2D images using the finite support properties of cubic B-splines. After initial affine alignment, each large image is split into a grid of smaller overlapping sub-images, which are individually registered using cubic B-splines transformations. Inside the overlapping regions between neighboring sub-images, the coefficients of the knots controlling the B-splines deformations are blended, to create a virtual large grid of knots for the whole image. The sub-images are resampled individually, using the new coefficients, and assembled together into a final large aligned image. We evaluated the method on a series of large transmission electron microscopy images and our results indicate significant improvements compared to both manual and affine alignment.

  16. Sagittarius

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Archer; abbrev. Sgr, gen. Sagittarii; area 867 sq. deg.) A southern zodiacal constellation which lies between Ophiuchus and Capricornus, and culminates at midnight in early July. Its origin dates back to Sumerian times, when it was identified with Nergal, a god of war, but today it is associated with Crotus, son of the Greek god Pan and the inventor of archery, and it is shown on early celes...

  17. Naval Coastal Warfare Operations from 2000 to Operation Iraqi Freedom and the Deficiencies that Prompted their Addition to the Naval Expeditionary Combat Command

    DTIC Science & Technology

    2009-11-02

    overmatched small boats sought refuge with the Boutwell but very little could be done and the 25ft boats were sent back to MABOT under the escort of a zodiac ...NAVAL COASTAL WARFARE OPERATIONS FROM 2000 TO OPERATION IRAQI FREEDOM AND THE DEFICIENCIES THAT PROMPTED THEIR ADDITION TO THE NAVAL EXPEDITIONARY...including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing

  18. Israel’s Blockade of Gaza, the Mavi Marmara Incident, and Its Aftermath

    DTIC Science & Technology

    2010-06-23

    Israeli navy zodiac boats intercepted them and naval commandos took over five ships, reportedly without incident. However, the Marmara resisted and...CRS Report for Congress Prepared for Members and Committees of Congress Israel’s Blockade of Gaza, the Mavi Marmara Incident, and Its...c11173008 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour

  19. Special Operations Forces of Hungary: Is a Transformation Necessary?

    DTIC Science & Technology

    2010-12-01

    inflatable Zodiac boats. With this, the battalion is capable to infiltrate two platoons at the same time through using water ways, and the battalion is...SPECIAL OPERATIONS FORCES OF HUNGARY: IS A TRANSFORMATION NECESSARY? A thesis presented to the Faculty of the U.S. Army Command and...General Staff College in partial fulfillment of the requirements for the degree MASTER OF MILITARY ART AND SCIENCE General Studies by

  20. On the definition of albedo and application to irregular particles

    NASA Technical Reports Server (NTRS)

    Hanner, M. S.; Giese, R. H.; Weiss, K.; Zerull, R.

    1981-01-01

    The various definitions of albedo used in planetary astronomy are reviewed. In particular, the Bond albedo, which refers only to the reflected and refracted components, is not applicable to small particles or highly irregular particles, where diffraction is not restricted to a well-defined lobe at small scattering angles. Measured scattering functions for irregular particles are presented in a normalized form and are applied to the case of zodiacal light.

  1. Taurus

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Bull; abbrev. Tau, gen. Tauri; area 797 sq. deg.) A northern zodiacal constellation which lies between Aries and Orion, and culminates at midnight in late November. It is one of the oldest constellations, dating back to when the Sun was in that part of the sky at the vernal (spring) equinox, between about 4000 and 1800 BC. Later, in Greek mythology, it was identified with the form assumed by...

  2. Aries

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Ram; abbrev. Ari, gen. Arietis; area 441 sq. deg.) A northern zodiacal constellation that lies between Taurus and Pisces, and culminates at midnight in late October. It represents the ram in Greek mythology whose golden fleece was the quest of Jason and the Argonauts. Its brightest stars were cataloged by Ptolemy (c. AD 100-175) in the Almagest. In Ptolemy's day the Sun was in Aries at the v...

  3. A likely detection of a local interplanetary dust cloud passing near the Earth in the AKARI mid-infrared all-sky map

    NASA Astrophysics Data System (ADS)

    Ishihara, D.; Kondo, T.; Kaneda, H.; Suzuki, T.; Nakamichi, K.; Takaba, S.; Kobayashi, H.; Masuda, S.; Ootsubo, T.; Pyo, J.; Onaka, T.

    2017-07-01

    Context. We are creating the AKARI mid-infrared all-sky diffuse maps. Through a foreground removal of the zodiacal emission, we serendipitously detected a bright residual component whose angular size is about 50° × 20° at a wavelength of 9 μm. Aims: We investigate the origin and the physical properties of the residual component. Methods: We measured the surface brightness of the residual component in the AKARI mid-infrared all-sky maps. Results: The residual component was significantly detected only in 2007 January, even though the same region was observed in 2006 July and 2007 July, which shows that it is not due to the Galactic emission. We suggest that this may be a small cloud passing near the Earth. By comparing the observed intensity ratio of I9 μm/I18 μm with the expected intensity ratio assuming thermal equilibrium of dust grains at 1 AU for various dust compositions and sizes, we find that dust grains in the moving cloud are likely to be much smaller than typical grains that produce the bulk of the zodiacal light. Conclusions: Considering the observed date and position, it is likely that it originates in the solar coronal mass ejection (CME) which took place on 2007 January 25.

  4. Task-dependent cold stress during expeditions in Antarctic environments

    PubMed Central

    Morris, Drew M.; Pilcher, June J.; Powell, Robert B.

    2017-01-01

    ABSTRACT This study seeks to understand the degree of body cooling, cold perception and physical discomfort during Antarctic tour excursions. Eight experienced expedition leaders across three Antarctic cruise voyages were monitored during occupational tasks: kayaking, snorkelling and zodiac outings. Subjective cold perception and discomfort were recorded using a thermal comfort assessment and skin temperature was recorded using a portable data logger. Indoor cabin temperature and outdoor temperature with wind velocity were used as measures of environmental stress. Physical activity level and clothing insulation were estimated using previous literature. Tour leaders experienced a 6°C (2°C wind chill) environment for an average of 6 hours each day. Leaders involved in kayaking reported feeling colder and more uncomfortable than other leaders, but zodiac leaders showed greater skin temperature cooling. Occupational experience did not predict body cooling or cold stress perception. These findings indicate that occupational cold stress varies by activity and measurement methodology. The current study effectively used objective and subjective measures of cold-stress to identify factors which can contribute to risk in the Antarctic tourism industry. Results suggest that the type of activity may moderate risk of hypothermia, but not discomfort, potentially putting individuals at risk for cognitive related mistakes and cold injuries. PMID:28990466

  5. Task-dependent cold stress during expeditions in Antarctic environments.

    PubMed

    Morris, Drew M; Pilcher, June J; Powell, Robert B

    2017-01-01

    This study seeks to understand the degree of body cooling, cold perception and physical discomfort during Antarctic tour excursions. Eight experienced expedition leaders across three Antarctic cruise voyages were monitored during occupational tasks: kayaking, snorkelling and zodiac outings. Subjective cold perception and discomfort were recorded using a thermal comfort assessment and skin temperature was recorded using a portable data logger. Indoor cabin temperature and outdoor temperature with wind velocity were used as measures of environmental stress. Physical activity level and clothing insulation were estimated using previous literature. Tour leaders experienced a 6°C (2°C wind chill) environment for an average of 6 hours each day. Leaders involved in kayaking reported feeling colder and more uncomfortable than other leaders, but zodiac leaders showed greater skin temperature cooling. Occupational experience did not predict body cooling or cold stress perception. These findings indicate that occupational cold stress varies by activity and measurement methodology. The current study effectively used objective and subjective measures of cold-stress to identify factors which can contribute to risk in the Antarctic tourism industry. Results suggest that the type of activity may moderate risk of hypothermia, but not discomfort, potentially putting individuals at risk for cognitive related mistakes and cold injuries.

  6. Effect of packing method on the randomness of disc packings

    NASA Astrophysics Data System (ADS)

    Zhang, Z. P.; Yu, A. B.; Oakeshott, R. B. S.

    1996-06-01

    The randomness of disc packings, generated by random sequential adsorption (RSA), random packing under gravity (RPG) and Mason packing (MP) which gives a packing density close to that of the RSA packing, has been analysed, based on the Delaunay tessellation, and is evaluated at two levels, i.e. the randomness at individual subunit level which relates to the construction of a triangle from a given edge length distribution and the randomness at network level which relates to the connection between triangles from a given triangle frequency distribution. The Delaunay tessellation itself is also analysed and its almost perfect randomness at the two levels is demonstrated, which verifies the proposed approach and provides a random reference system for the present analysis. It is found that (i) the construction of a triangle subunit is not random for the RSA, MP and RPG packings, with the degree of randomness decreasing from the RSA to MP and then to RPG packing; (ii) the connection of triangular subunits in the network is almost perfectly random for the RSA packing, acceptable for the MP packing and not good for the RPG packing. Packing method is an important factor governing the randomness of disc packings.

  7. Location Privacy for Mobile Crowd Sensing through Population Mapping †

    PubMed Central

    Shin, Minho; Cornelius, Cory; Kapadia, Apu; Triandopoulos, Nikos; Kotz, David

    2015-01-01

    Opportunistic sensing allows applications to “task” mobile devices to measure context in a target region. For example, one could leverage sensor-equipped vehicles to measure traffic or pollution levels on a particular street or users' mobile phones to locate (Bluetooth-enabled) objects in their vicinity. In most proposed applications, context reports include the time and location of the event, putting the privacy of users at increased risk: even if identifying information has been removed from a report, the accompanying time and location can reveal sufficient information to de-anonymize the user whose device sent the report. We propose and evaluate a novel spatiotemporal blurring mechanism based on tessellation and clustering to protect users' privacy against the system while reporting context. Our technique employs a notion of probabilistic k-anonymity; it allows users to perform local blurring of reports efficiently without an online anonymization server before the data are sent to the system. The proposed scheme can control the degree of certainty in location privacy and the quality of reports through a system parameter. We outline the architecture and security properties of our approach and evaluate our tessellation and clustering algorithm against real mobility traces. PMID:26131676

  8. A tool to convert CAD models for importation into Geant4

    NASA Astrophysics Data System (ADS)

    Vuosalo, C.; Carlsmith, D.; Dasu, S.; Palladino, K.; LUX-ZEPLIN Collaboration

    2017-10-01

    The engineering design of a particle detector is usually performed in a Computer Aided Design (CAD) program, and simulation of the detector’s performance can be done with a Geant4-based program. However, transferring the detector design from the CAD program to Geant4 can be laborious and error-prone. SW2GDML is a tool that reads a design in the popular SOLIDWORKS CAD program and outputs Geometry Description Markup Language (GDML), used by Geant4 for importing and exporting detector geometries. Other methods for outputting CAD designs are available, such as the STEP format, and tools exist to convert these formats into GDML. However, these conversion methods produce very large and unwieldy designs composed of tessellated solids that can reduce Geant4 performance. In contrast, SW2GDML produces compact, human-readable GDML that employs standard geometric shapes rather than tessellated solids. This paper will describe the development and current capabilities of SW2GDML and plans for its enhancement. The aim of this tool is to automate importation of detector engineering models into Geant4-based simulation programs to support rapid, iterative cycles of detector design, simulation, and optimization.

  9. Creating Tesselations with Pavement Chalk: Implementing Best Practices in Mathematics

    ERIC Educational Resources Information Center

    Furner, Joseph M.; Goodman, Barbara; Meeks, Shirley

    2004-01-01

    Implementing best practices like cooperative learning, using concrete manipulatives, problem solving, technology, active learning, multi-age grouping, and team teaching have shown benefits for students when learning mathematics concepts within the curriculum (Zemelman, Daniels & Hyde, 1998; NCTM, 2000). What started as a professional development…

  10. Movements and Spatial Use of Odontocetes in the Western Main Hawaiian Islands: Results from Satellite-Tagging and Photo-Identification off Kaua’i and Ni’ihau in July/August 2011

    DTIC Science & Technology

    2012-06-07

    outfitted with a tower and bow pulpit; a 24’ rigid-hulled Zodiac ; and a 32’ Sea Cat. When the PMRF range was open to vessel traffic, survey efforts...Movements and spatial use of odontocetes in the western main Hawaiian Islands: results from satellite-tagging and photo...101 Pivers Island Road Beaufort, NC 28516 Annual progress report under Grant No. N00244-10-1-0048 from the Naval Postgraduate School June 7

  11. Special Operations Research Topics 2015

    DTIC Science & Technology

    2014-01-01

    McNally) Upper Right: A U.S. Navy SEAL provides cover while two Zodiac fast boats with soldiers from the U.S. Special Forces and the Jordanian Special...Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per...response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and

  12. Validation Test Report for WAVEWATCH III

    DTIC Science & Technology

    2012-11-30

    scales relevant to operation of a zodiac , to larger length-scales, relevant to activities on the largest ships, such as ship-to-ship transfer of...average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data...display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  13. Surface Photometry of Celestial Sources from a Space Vehicle: Introduction and Observational Procedures*

    PubMed Central

    Roach, Franklin E.; Carroll, Benjamin; Aller, Lawrence H.; Smith, Leroi

    1972-01-01

    Diffuse celestial sources of relatively low surface brightness such as the Milky Way, zodiacal light, and gegenschein (or contre lumière) can be studied most reliably from above the earth's atmosphere with equipment flown in artificial satellites. We review the techniques used and some of the difficulties encountered in day-time observations from satellites by the use of a special photometer and polarimeter flown in the orbiting skylab observatory, OSO-6. PMID:16591970

  14. 76 FR 60934 - Notice of Permit Application Received Under the Antarctic Conservation Act of 1978

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-30

    ...Notice is hereby given that the National Science Foundation (NSF) has received a waste management permit application for Quark Expeditions' cruise ships to conduct a number of activities, including: shore excursions via zodiac or helicopter, camping ashore or extended stays, mountaineering, kayaking, helicopter flight seeing/emergency landings, and skiing. The application is submitted by Quark Expeditions of Waterbury, Vermont and submitted to NSF pursuant to regulations issued under the Antarctic Conservation Act of 1978.

  15. Background starlight observed from Pioneer 10. [beyond asteroid belt

    NASA Technical Reports Server (NTRS)

    Weinberg, J. L.; Hanner, M. S.; Beeson, D. E.; Deshields, L. M., II; Green, B. A.

    1974-01-01

    The results of background starlight observations are reviewed that were obtained by the Pioneer 10 asteroid-Jupiter probe when, after passage beyond the asteroid belt, its imaging photopolarimeter observed integrated starlight and diffuse galactic light for the first time in the absence of zodiacal light. Brightnesses in the blue are presented with and without individually resolved stars for regions of the sky observed when Pioneer 10 was 4.64 astronomical units from the sun.

  16. Naval Response to a Changed Security Environment: Maritime Security in the Mediterranean

    DTIC Science & Technology

    2007-01-01

    other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a...PAGES 28 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8...elements. The first was to use inflatable Zodiac -type speedboats to attack ships. The second was to blow up medium-sized vessels near other ships

  17. The C2 Workstation and Data Replication over Disadvantaged Tactical Communication Links

    DTIC Science & Technology

    2007-09-01

    person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number...SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 14 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b...PUBLIC RELEASE C2WS Physical Environment Zodiac Network Radio Network Combat Level Node (Vehicle) Radio Local Store Local Store Local Store To Other

  18. An Analysis of Strategic Planning to Support the United States Special Operations Forces’ C3 Interoperability.

    DTIC Science & Technology

    1992-09-01

    59) The problem could be attributed to too many sophisticated systems, the lack of a true interservice focal point with the ability to control DoD...the study and yet still provide a true picture of interservice communication interoperability problems within USSOCOM, the study was limited to...they referred to as the signs of the Zodiac, and are still cited today in astronomy and horoscopes (8:22-36). Ptolemy of Alexandria is given credit

  19. The Impact of Zodiac Signs on Human Nature and Fate

    NASA Astrophysics Data System (ADS)

    Gasparyan, Naira

    2015-07-01

    Horoscope signs have unavoidable impact on human behaviour and interests, health and even fate. Moreover, intermingled with the impact of planets they become a powerful force able to bring about unbelievable changes. The investigation reveals that horoscopes have existed in the Armenian reality since ancient times. The most striking fact about their eistence is that in order to have and use zodiak signs in one's national culture, the nation should first of all have sufficient knowledge in Astrological Sciences since the system of zodiak signs has a direct reference to the cognitive processes and scientific knowledge of the universe, astrological issues and sometimes even there is a hint on hidden signs and messages. Anania Shirakatsi, one of the learned Armenians, had to display much diplomacy with the Armenian Church and religion when discussing the topic in his manuscripts. His observations are still of much importance and vitality even today.

  20. Honeycombing The Icosahedron and Icosahedroning the Sphere

    Treesearch

    Joseph M McCollum

    2001-01-01

    This paper is an attempt to trace the theoretical foundations of the Forest Inventory and Analysis and Forest Health Monitoring hexagon networks. It is important in case one might desire to alter the intensity of the grid or lay down a new grid in Puerto Rico and the U.S. Virgin Islands, for instance. The network comes from tessellating an icosahedron with hexagons and...

  1. Geographic variation in host fish use and larval metamorphosis for the endangered dwarf wedgemussel

    USGS Publications Warehouse

    White, Barbara (St. John); Ferreri, C. Paola; Lellis, William A.; Wicklow, Barry J.; Cole, Jeffrey C.

    2017-01-01

    Host fishes play a crucial role in survival and dispersal of freshwater mussels (Unionoida), particularly rare unionids at conservation risk. Intraspecific variation in host use is not well understood for many mussels, including the endangered dwarf wedgemussel (Alasmidonta heterodon) in the USA.Host suitability of 33 fish species for dwarf wedgemussel glochidia (larvae) from the Delaware and Connecticut river basins was tested in laboratory experiments over 9 years. Relative suitability of three different populations of a single host fish, the tessellated darter (Etheostoma olmstedi), from locations in the Connecticut, Delaware, and Susquehanna river basins, was also tested.Connecticut River basin A. heterodon metamorphosed into juvenile mussels on tessellated darter, slimy sculpin (Cottus cognatus), and Atlantic salmon (Salmo salar) parr. Delaware River basin mussels metamorphosed using these three species, as well as brown trout (Salmo trutta), banded killifish (Fundulus diaphanus), mottled sculpin (Cottus bairdii), striped bass (Morone saxatilis), and shield darter (Percina peltata). Atlantic salmon, striped bass, and sculpins were highly effective hosts, frequently generating 5+ juveniles per fish (JPF) and metamorphosis success (MS; proportion of attaching larvae that successfully metamorphose) ≥ 0.4, and producing juveniles in repeated trials.In experiments on tessellated darters, mean JPF and MS values decreased as isolation between the mussel source (Connecticut River) and each fish source increased; mean JPF = 10.45, 6.85, 4.14, and mean MS = 0.50, 0.41, and 0.34 in Connecticut, Delaware, and Susquehanna river darters, respectively. Host suitability of individual darters was highly variable (JPF = 2–11; MS = 0.20–1.0).The results show that mussel–host fish compatibility in A. heterodon differs among Atlantic coastal rivers, and suggest that hosts including anadromous Atlantic salmon and striped bass may help sustain A. heterodon in parts of

  2. SAFARI new and improved: extending the capabilities of SPICA's imaging spectrometer

    NASA Astrophysics Data System (ADS)

    Roelfsema, Peter; Giard, Martin; Najarro, Francisco; Wafelbakker, Kees; Jellema, Willem; Jackson, Brian; Sibthorpe, Bruce; Audard, Marc; Doi, Yasuo; di Giorgio, Anna; Griffin, Matthew; Helmich, Frank; Kamp, Inga; Kerschbaum, Franz; Meyer, Michael; Naylor, David; Onaka, Takashi; Poglitch, Albrecht; Spinoglio, Luigi; van der Tak, Floris; Vandenbussche, Bart

    2014-08-01

    The Japanese SPace Infrared telescope for Cosmology and Astrophysics, SPICA, aims to provide astronomers with a truly new window on the universe. With a large -3 meter class- cold -6K- telescope, the mission provides a unique low background environment optimally suited for highly sensitive instruments limited only by the cosmic background itself. SAFARI, the SpicA FAR infrared Instrument SAFARI, is a Fourier Transform imaging spectrometer designed to fully exploit this extremely low far infrared background environment. The SAFARI consortium, comprised of European and Canadian institutes, has established an instrument reference design based on a Mach-Zehnder interferometer stage with outputs directed to three extremely sensitive Transition Edge Sensor arrays covering the 35 to 210 μm domain. The baseline instrument provides R > 1000 spectroscopic imaging capabilities over a 2' by 2' field of view. A number of modifications to the instrument to extend its capabilities are under investigation. With the reference design SAFARI's sensitivity for many objects is limited not only by the detector NEP but also by the level of broad band background radiation - the zodiacal light for the shorter wavelengths and satellite baffle structures for the longer wavelengths. Options to reduce this background are dedicated masks or dispersive elements which can be inserted in the optics as required. The resulting increase in sensitivity can directly enhance the prime science goals of SAFARI; with the expected enhanced sensitivity astronomers would be in a better position to study thousands of galaxies out to redshift 3 and even many hundreds out to redshifts of 5 or 6. Possibilities to increase the wavelength resolution, at least for the shorter wavelength bands, are investigated as this would significantly enhance SAFARI's capabilities to study star and planet formation in our own galaxy.

  3. Factors influencing medical informatics examination grade--can biorhythm, astrological sign, seasonal aspect, or bad statistics predict outcome?

    PubMed

    Petrovecki, Mladen; Rahelić, Dario; Bilić-Zulle, Lidija; Jelec, Vjekoslav

    2003-02-01

    To investigate whether and to what extent various parameters, such as individual characteristics, computer habits, situational factors, and pseudoscientific variables, influence Medical Informatics examination grade, and how inadequate statistical analysis can lead to wrong conclusions. The study included a total of 382 second-year undergraduate students at the Rijeka University School of Medicine in the period from 1996/97 to 2000/01 academic year. After passing the Medical Informatics exam, students filled out an anonymous questionnaire about their attitude toward learning medical informatics. They were asked to grade the course organization and curriculum content, and provide their date of birth; sex; study year; high school grades; Medical Informatics examination grade, type, and term; and describe their computer habits. From these data, we determined their zodiac signs and biorhythm. Data were compared by the use of t-test, one-way ANOVA with Tukey's honest significance difference test, and randomized complete block design ANOVA. Out of 21 variables analyzed, only 10 correlated with the average grade. Students taking Medical Informatics examination in the 1998/99 academic year earned lower average grade than any other generation. Significantly higher Medical Informatics exam grade was earned by students who finished a grammar high school; owned and regularly used a computer, Internet, and e-mail (p< or =0.002 for all items); passed an oral exam without taking a written test (p=0.004), or did not repeat the exam (p<0.001). Better high-school students and students with better grades from high-school informatics course also scored significantly better (p=0.032 and p<0.001, respectively). Grade in high-school mathematics, student's sex, and time of year when the examination was taken were not related to the grade, and neither were pseudoscientific parameters, such as student zodiac sign, zodiac sign quality, or biorhythm cycles, except when intentionally

  4. Ground Optical Signal Processing Architecture for Contributing Space-Based SSA Sensor Data

    DTIC Science & Technology

    2014-09-01

    Where 2 zodiacal 2 thermalphotons dNdNsignaldN  and readdN is the read noise in noise-electrons. dNthermal is the photoelectron noise due...PhD, USAF Defense Advanced Research Projects Agency, Arlington, VA. ABSTRACT DARPA’s OrbitOutlook aims to augment the performance of the Space...SDA) and determine when satellites are at risk. OrbitOutlook also seeks to demonstrate the ability to rapidly include new instruments to alert for

  5. Selection, Prioritization, and Characteristics of Kepler Target Stars

    DTIC Science & Technology

    2010-04-20

    contributions from zodiacal emission as well as background stars): r = F∗ F∗ + Fbg . (5) The photometric aperture is defined as the set of pixels that... The Astrophysical Journal Letters, 713:L109–L114, 2010 April 20 doi:10.1088/2041-8205/713/2/L109 C© 2010. The American Astronomical Society. All...rights reserved. Printed in the U.S.A. SELECTION, PRIORITIZATION, AND CHARACTERISTICS OF KEPLER TARGET STARS Natalie M. Batalha1, William J. Borucki2

  6. Naval Coastal Warfare Operations from 2000 to Operation Iraqi Freedom and the Deficiencies that Prompted their Addition to the Naval Expeditionary Combat Command

    DTIC Science & Technology

    2009-12-03

    overmatched small boats sought refuge with the Boutwell but very little could be done and the 25ft boats were sent back to MABOT under the escort of a zodiac ...solely those of the author, and do not represent the views of the US Army School of Advanced Military Studies, the US Army Command and General Staff...College, the United States Army, the Department of Defense, or any other US government agency. Cleared for public release: distribution unlimited

  7. Tracking Nonradial Motions and Azimuthal Expansions of Interplanetary CMEs with the Solar Mass Ejection Imager

    DTIC Science & Technology

    2010-01-01

    from Sun to Earth • Provide an all-sky view, updated every orbit • Detect signal at 1% of background ( zodiacal light and stars) The SMEI uses 3...hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and...currently valid OMB control number PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 15-06-2010 RF.PRTNT > Q. C 4

  8. Dynamics of Solar System Dust

    NASA Technical Reports Server (NTRS)

    Dermott, Stanley F.

    2002-01-01

    The ongoing aim of the research is to investigate the dynamical and physical evolution of interplanetary dust particles in order to produce a detailed global model of the zodiacal cloud and its constituent components that is capable of predicting thermal fluxes in mid-infrared wave bands to an accuracy of 1% or better; with the additional aim of exploiting this research as a basis for predicting structure in exozodiacal clouds that may be signatures of unseen planets.

  9. Symbolics of the constellations of sagittarius and centaurus in russian traditional culture

    NASA Astrophysics Data System (ADS)

    Bagdasarov, R.

    2001-12-01

    Centaurus falls into the category of 'imaginary animals'. The Russian tradition used not only the symbol Sgr (a result of its acquaintance with the circle of Zodiac), but also the symbol Cen, which fact, as we shall demonstrate, is an evidence of certain mythological-astronomical conceptions. Both the constellations Sagittarius (Sgr) and Centaurus (Cen) are usually represented as versions of the picture of a fantastic being, a Centaur, shaped as man from head to waist, and as an animal, mostly, a horse, from waist down. 'Centaurus' (from the Greek word kev (or kevw)) for 'kill' and o, for 'bull') means 'bull killer', and is probably related to the opposition of the zodiacal constellations Taurus and Sagittarius. When the latter begins to rise on to the night sky, the former disappears completely from view. Sagittarius is represented at ancient monuments related to astronomy as a centaur holding a bow and pointing at certain stars. The constellation of Centaurus is also symbolised by a centaur, but holding not a bow, but a staff or a spear in one hand and an 'animal of sacrifice' in the other (Higinus, Astronomica, III, 37, 1; Chernetsov, 1975, Figure 1). The attributes stand for the Peliases Spear (The Mithological Dictionary, 1991), depicted in astrological maps as The Spear of Centaurus1, The Wolf (Lupus), the Panther or the Beast (Flammarion, 1994).

  10. IRAS sky survey atlas: Explanatory supplement

    NASA Technical Reports Server (NTRS)

    Wheelock, S. L.; Gautier, T. N.; Chillemi, J.; Kester, D.; Mccallon, H.; Oken, C.; White, J.; Gregorich, D.; Boulanger, F.; Good, J.

    1994-01-01

    This Explanatory Supplement accompanies the IRAS Sky Survey Atlas (ISSA) and the ISSA Reject Set. The first ISSA release in 1991 covers completely the high ecliptic latitude sky, absolute value of beta is greater than 50 deg, with some coverage down to the absolute value of beta approx. equal to 40 deg. The second ISSA release in 1992 covers ecliptic latitudes of 50 deg greater than the absolute value of beta greater than 20 deg, with some coverage down to the absolute value of beta approx. equal to 13 deg. The remaining fields covering latitudes within 20 deg of the ecliptic plane are of reduced quality compared to the rest of the ISSA fields and therefore are released as a separate IPAC product, the ISSA Reject Set. The reduced quality is due to contamination by zodiacal emission residuals. Special care should be taken when using the ISSA Reject images. In addition to information on the ISSA images, some information is provided in this Explanatory Supplement on the IRAS Zodiacal History File (ZOHF), Version 3.0, which was described in the December 1988 release memo. The data described in this Supplement are available at the National Space Science Data Center (NSSDC) at the Goddard Space Flight Center. The interested reader is referred to the NSSDC for access to the IRAS Sky Survey Atlas (ISSA).

  11. Observations of the diffuse UV radiation field

    NASA Technical Reports Server (NTRS)

    Murthy, Jayant; Henry, R. C.; Feldman, P. D.; Tennyson, P. D.

    1989-01-01

    Spectra are presented for the diffuse UV radiation field between 1250 to 3100 A from eight different regions of the sky, which were obtained with the Johns Hopkins UVX experiment. UVX flew aboard the Space Shuttle Columbia (STS-61C) in January 1986 as part of the Get-Away Special project. The experiment consisted of two 1/4 m Ebert-Fastie spectrometers, covering the spectral range 1250 to 1700 A at 17 A resolution and 1600 to 3100 A at 27 A resolution, respectively, with a field of view of 4 x .25 deg, sufficiently small to pick out regions of the sky with no stars in the line of sight. Values were found for the diffuse cosmic background ranging in intensity from 300 to 900 photons/sq cm/sec/sr/A. The cosmic background is spectrally flat from 1250 to 3100 A, within the uncertainties of each spectrometer. The zodiacal light begins to play a significant role in the diffuse radiation field above 2000 A, and its brightness was determined relative to the solar emission. Observed brightnesses of the zodiacal light in the UV remain almost constant with ecliptic latitude, unlike the declining visible brightnesses, possibly indicating that those (smaller) grains responsible for the UV scattering have a much more uniform distribution with distance from the ecliptic plane than do those grains responsible for the visible scattering.

  12. A consistent methodology for optimal shape design of graphene sheets to maximize their fundamental frequencies considering topological defects

    NASA Astrophysics Data System (ADS)

    Shi, Jin-Xing; Ohmura, Keiichiro; Shimoda, Masatoshi; Lei, Xiao-Wen

    2018-07-01

    In recent years, shape design of graphene sheets (GSs) by introducing topological defects for enhancing their mechanical behaviors has attracted the attention of scholars. In the present work, we propose a consistent methodology for optimal shape design of GSs using a combination of the molecular mechanics (MM) method, the non-parametric shape optimization method, the phase field crystal (PFC) method, Voronoi tessellation, and molecular dynamics (MD) simulation to maximize their fundamental frequencies. At first, we model GSs as continuum frame models using a link between the MM method and continuum mechanics. Then, we carry out optimal shape design of GSs in fundamental frequency maximization problem based on a developed shape optimization method for frames. However, the obtained optimal shapes of GSs only consisting of hexagonal carbon rings are unstable that do not satisfy the principle of least action, so we relocate carbon atoms on the optimal shapes by introducing topological defects using the PFC method and Voronoi tessellation. At last, we perform the structural relaxation through MD simulation to determine the final optimal shapes of GSs. We design two examples of GSs and the optimal results show that the fundamental frequencies of GSs can be significantly enhanced according to the optimal shape design methodology.

  13. A 3D coupled hydro-mechanical granular model for the prediction of hot tearing formation

    NASA Astrophysics Data System (ADS)

    Sistaninia, M.; Phillion, A. B.; Drezet, J.-M.; Rappaz, M.

    2012-07-01

    A new 3D coupled hydro-mechanical granular model that simulates hot tearing formation in metallic alloys is presented. The hydro-mechanical model consists of four separate 3D modules. (I) The Solidification Module (SM) is used for generating the initial solid-liquid geometry. Based on a Voronoi tessellation of randomly distributed nucleation centers, this module computes solidification within each polyhedron using a finite element based solute diffusion calculation for each element within the tessellation. (II) The Fluid Flow Module (FFM) calculates the solidification shrinkage and deformation-induced pressure drop within the intergranular liquid. (III) The Semi-solid Deformation Module (SDM) is used to simulate deformation of the granular structure via a combined finite element / discrete element method. In this module, deformation of the solid grains is modeled using an elasto-viscoplastic constitutive law. (IV) The Failure Module (FM) is used to simulate crack initiation and propagation with the fracture criterion estimated from the overpressure required to overcome the capillary forces at the liquid-gas interface. The FFM, SDM, and FM are coupled processes since solid deformation, intergranular flow, and crack initiation are deeply linked together. The granular model predictions have been validated against bulk data measured experimentally and calculated with averaging techniques.

  14. Detecting kinematic boundary surfaces in phase space: particle mass measurements in SUSY-like events

    DOE PAGES

    Debnath, Dipsikha; Gainer, James S.; Kilic, Can; ...

    2017-06-19

    We critically examine the classic endpoint method for particle mass determination, focusing on difficult corners of parameter space, where some of the measurements are not independent, while others are adversely affected by the experimental resolution. In such scenarios, mass differences can be measured relatively well, but the overall mass scale remains poorly constrained. Using the example of the standard SUSY decay chain q ~→χ ~ 0 2→ℓ ~→χ ~ 0 1 , we demonstrate that sensitivity to the remaining mass scale parameter can be recovered by measuring the two-dimensional kinematical boundary in the relevant three-dimensional phase space of invariant massesmore » squared. We develop an algorithm for detecting this boundary, which uses the geometric properties of the Voronoi tessellation of the data, and in particular, the relative standard deviation (RSD) of the volumes of the neighbors for each Voronoi cell in the tessellation. We propose a new observable, Σ¯ , which is the average RSD per unit area, calculated over the hypothesized boundary. We show that the location of the Σ¯ maximum correlates very well with the true values of the new particle masses. Our approach represents the natural extension of the one-dimensional kinematic endpoint method to the relevant three dimensions of invariant mass phase space.« less

  15. A Programmable Cellular-Automata Polarized Dirac Vacuum

    NASA Astrophysics Data System (ADS)

    Osoroma, Drahcir S.

    2013-09-01

    We explore properties of a `Least Cosmological Unit' (LCU) as an inherent spacetime raster tiling or tessellating the unique backcloth of Holographic Anthropic Multiverse (HAM) cosmology as an array of programmable cellular automata. The HAM vacuum is a scale-invariant HD extension of a covariant polarized Dirac vacuum with `bumps' and `holes' typically described by extended electromagnetic theory corresponding to an Einstein energy-dependent spacetime metric admitting a periodic photon mass. The new cosmology incorporates a unique form of M-Theoretic Calabi-Yau-Poincaré Dodecadedral-AdS5-DS5space (PDS) with mirror symmetry best described by an HD extension of Cramer's Transactional Interpretation when integrated also with an HD extension of the de Broglie-Bohm-Vigier causal interpretation of quantum theory. We incorporate a unique form of large-scale additional dimensionality (LSXD) bearing some similarity to that conceived by Randall and Sundrum; and extend the fundamental basis of our model to the Unified Field, UF. A Sagnac Effect rf-pulsed incursive resonance hierarchy is utilized to manipulate and ballistically program the geometric-topological properties of this putative LSXD space-spacetime network. The model is empirically testable; and it is proposed that a variety of new technologies will arise from ballistic programming of tessellated LCU vacuum cellular automata.

  16. Simulation of Semi-Solid Material Mechanical Behavior Using a Combined Discrete/Finite Element Method

    NASA Astrophysics Data System (ADS)

    Sistaninia, M.; Phillion, A. B.; Drezet, J.-M.; Rappaz, M.

    2011-01-01

    As a necessary step toward the quantitative prediction of hot tearing defects, a three-dimensional stress-strain simulation based on a combined finite element (FE)/discrete element method (DEM) has been developed that is capable of predicting the mechanical behavior of semisolid metallic alloys during solidification. The solidification model used for generating the initial solid-liquid structure is based on a Voronoi tessellation of randomly distributed nucleation centers and a solute diffusion model for each element of this tessellation. At a given fraction of solid, the deformation is then simulated with the solid grains being modeled using an elastoviscoplastic constitutive law, whereas the remaining liquid layers at grain boundaries are approximated by flexible connectors, each consisting of a spring element and a damper element acting in parallel. The model predictions have been validated against Al-Cu alloy experimental data from the literature. The results show that a combined FE/DEM approach is able to express the overall mechanical behavior of semisolid alloys at the macroscale based on the morphology of the grain structure. For the first time, the localization of strain in the intergranular regions is taken into account. Thus, this approach constitutes an indispensible step towards the development of a comprehensive model of hot tearing.

  17. Detecting kinematic boundary surfaces in phase space: particle mass measurements in SUSY-like events

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Debnath, Dipsikha; Gainer, James S.; Kilic, Can

    We critically examine the classic endpoint method for particle mass determination, focusing on difficult corners of parameter space, where some of the measurements are not independent, while others are adversely affected by the experimental resolution. In such scenarios, mass differences can be measured relatively well, but the overall mass scale remains poorly constrained. Using the example of the standard SUSY decay chain q ~→χ ~ 0 2→ℓ ~→χ ~ 0 1 , we demonstrate that sensitivity to the remaining mass scale parameter can be recovered by measuring the two-dimensional kinematical boundary in the relevant three-dimensional phase space of invariant massesmore » squared. We develop an algorithm for detecting this boundary, which uses the geometric properties of the Voronoi tessellation of the data, and in particular, the relative standard deviation (RSD) of the volumes of the neighbors for each Voronoi cell in the tessellation. We propose a new observable, Σ¯ , which is the average RSD per unit area, calculated over the hypothesized boundary. We show that the location of the Σ¯ maximum correlates very well with the true values of the new particle masses. Our approach represents the natural extension of the one-dimensional kinematic endpoint method to the relevant three dimensions of invariant mass phase space.« less

  18. Detecting kinematic boundary surfaces in phase space: particle mass measurements in SUSY-like events

    NASA Astrophysics Data System (ADS)

    Debnath, Dipsikha; Gainer, James S.; Kilic, Can; Kim, Doojin; Matchev, Konstantin T.; Yang, Yuan-Pao

    2017-06-01

    We critically examine the classic endpoint method for particle mass determination, focusing on difficult corners of parameter space, where some of the measurements are not independent, while others are adversely affected by the experimental resolution. In such scenarios, mass differences can be measured relatively well, but the overall mass scale remains poorly constrained. Using the example of the standard SUSY decay chain \\tilde{q}\\to {\\tilde{χ}}_2^0\\to \\tilde{ℓ}\\to {\\tilde{χ}}_1^0 , we demonstrate that sensitivity to the remaining mass scale parameter can be recovered by measuring the two-dimensional kinematical boundary in the relevant three-dimensional phase space of invariant masses squared. We develop an algorithm for detecting this boundary, which uses the geometric properties of the Voronoi tessellation of the data, and in particular, the relative standard deviation (RSD) of the volumes of the neighbors for each Voronoi cell in the tessellation. We propose a new observable, \\overline{Σ} , which is the average RSD per unit area, calculated over the hypothesized boundary. We show that the location of the \\overline{Σ} maximum correlates very well with the true values of the new particle masses. Our approach represents the natural extension of the one-dimensional kinematic endpoint method to the relevant three dimensions of invariant mass phase space.

  19. Hydrodynamic Interactions during Launch and Recovery of a Small Boat from a Ship in a Seaway

    DTIC Science & Technology

    2014-11-28

    during launch and recovery. The RHIB is based on a Zodiac H935, with properties given in Table 1 when loaded with 12 person- nel. Figure 1 shows the hull...and recovery of a small craft from a larger ship, wave-induced motions of the larger ship will influence dy- namic loads on the crane. The motions of... the small craft will be a major determinant of the safety of onboard personnel. This paper exam- ines wave-induced motions during launch and recovery

  20. Movements and Spatial Use of Odontocetes in the Western Main Hawaiian Islands: Results of a Three-Year Study Off O’ahu and Kaua’i

    DTIC Science & Technology

    2013-04-03

    Kaua‘i surveys), the 96’ R/V Searcher and a 15’ rigid-hulled inflatable (February 2011), and a 24’ rigid-hulled Zodiac (July/August 2011, 2012). Off...SPATIAL USE OF ODONTOCETES IN THE WESTERN MAIN HAWAIIAN ISLANDS: RESULTS OF A THREE-YEAR STUDY OFF O‘AHU AND KAUA‘I by Robin W. Baird, Daniel...President Provost The report entitled “Movements and Spatial Use of Odontocetes in the Western Main Hawaiian Islands: Results of a Three-Year

  1. Method and apparatus for detection of charge on ions and particles

    DOEpatents

    Fuerstenau, Stephen Douglas; Soli, George Arthur

    2002-01-01

    The present invention provides a tessellated array detector with charge collecting plate (or cup) electrode pixels and amplifying circuitry integrated into each pixel making it sensitive to external electrostatic charge; a micro collector/amplifier pixel design possessing a small capacitance to ensure a high charge to voltage signal conversion for low noise/high sensitivity operation; a micro-fabricated array of such pixels to create a useful macroscopic target area for ion and charged particle collection.

  2. Build YOUR All-Sky View with Aladin

    NASA Astrophysics Data System (ADS)

    Oberto, A.; Fernique, P.; Boch, T.; Bonnarel, F.

    2011-07-01

    From the need to extend the display outside the boundaries of a single image, the Aladin team recently developed a new feature to visualize wide areas or even all of the sky. This all-sky view is particularly useful for visualization of very large objects and, with coverage of the whole sky, maps from the Planck satellite. To improve on this capability, some catalogs and maps have been built from many surveys (e.g., DSS, IRIS, GLIMPSE, SDSS, 2MASS) in mixed resolutions, allowing progressive display. The maps are constructed by mosaicing individual images. Now, we provide a new tool to build an all-sky view with your own images. From the images you have selected, it will compose a mosaic with several resolutions (HEALPix tessellation), and organize them to allow their progressive display in Aladin. For convenience, you can export it to a HEALPix map, or share it with the community through Aladin from your web site or eventually from the CDS image collection.

  3. The future of the CAVE

    NASA Astrophysics Data System (ADS)

    Defanti, Thomas A.; Acevedo, Daniel; Ainsworth, Richard A.; Brown, Maxine D.; Cutchin, Steven; Dawe, Gregory; Doerr, Kai-Uwe; Johnson, Andrew; Knox, Chris; Kooima, Robert; Kuester, Falko; Leigh, Jason; Long, Lance; Otto, Peter; Petrovic, Vid; Ponto, Kevin; Prudhomme, Andrew; Rao, Ramesh; Renambot, Luc; Sandin, Daniel J.; Schulze, Jurgen P.; Smarr, Larry; Srinivasan, Madhu; Weber, Philip; Wickham, Gregory

    2011-03-01

    The CAVE, a walk-in virtual reality environment typically consisting of 4-6 3 m-by-3 m sides of a room made of rear-projected screens, was first conceived and built in 1991. In the nearly two decades since its conception, the supporting technology has improved so that current CAVEs are much brighter, at much higher resolution, and have dramatically improved graphics performance. However, rear-projection-based CAVEs typically must be housed in a 10 m-by-10 m-by-10 m room (allowing space behind the screen walls for the projectors), which limits their deployment to large spaces. The CAVE of the future will be made of tessellated panel displays, eliminating the projection distance, but the implementation of such displays is challenging. Early multi-tile, panel-based, virtual-reality displays have been designed, prototyped, and built for the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia by researchers at the University of California, San Diego, and the University of Illinois at Chicago. New means of image generation and control are considered key contributions to the future viability of the CAVE as a virtual-reality device.

  4. Zodiacal Exoplanets in Time: Searching for Young Stars in K2

    NASA Astrophysics Data System (ADS)

    Morris, Nathan Ryan; Mann, Andrew; Rizzuto, Aaron

    2018-01-01

    Observations of planetary systems around young stars provide insight into the early stages of planetary system formation. Nearby young open clusters such as the Hyades, Pleiades, and Praesepe provide important benchmarks for the properties of stellar systems in general. These clusters are all known to be less than 1 Gyr old, making them ideal targets for a survey of young planetary systems. Few transiting planets have been detected around clusters stars, however, so this alone is too small of a sample. K2, the revived Kepler mission, has provided a vast number of light curves for young stars in clusters and elsewhere in the K2 field. This provides us with the opportunity to extend the sample of young systems to field stars while calibrating with cluster stars. We compute rotational periods from starspot patterns for ~36,000 K2 targets and use gyrochronological relationships derived from cluster stars to determine their ages. From there, we have begun searching for planets around young stars outside the clusters with the ultimate goal of shedding light on how planets and planetary systems evolve in their early, most formative years.

  5. Zodiacal Exoplanets in Time: Searching for Young Stars in K2

    NASA Astrophysics Data System (ADS)

    Morris, Nathan; Mann, Andrew W.

    2017-06-01

    Nearby young, open clusters such as the Hyades, Pleiades, and Praesepe provide an important reference point for the properties of stellar systems in general. In each cluster, all stars are of the same known age. As such, observations of planetary systems around these stars can be used to gain insight into the early stages of planetary system formation. K2, the revived Kepler mission, has provided a vast number of light curves for young stars in the and elsewhere in the K2 field. We aim to compute rotational periods from sunspot patterns for all K2 target stars and use gyrochronometric relationships derived from cluster stars to determine their ages. From there, we will search for planets around young stars outside the clusters with the ultimate goal of shedding light on how planets and planetary systems evolve with time.

  6. An Application of the Cosmologic Concepts and Astronomical Symbols in the Ancient Medical Science and Astrology Systems

    NASA Astrophysics Data System (ADS)

    Pikichyan, H. V.

    2015-07-01

    Employing the cosmologic concepts and astronomical symbols, the features of the ancient subjective approach of the achievement or perception of the knowledge and its systematic delivery ways are presented. In particular, the ancient systems of the natural medical science and the art of astrology are discussed, whereas the relations of the five cosmological elements, three dynamical agents, nine luminaries and twelve zodiac signs are applied. It is pointed out some misunderstandings encountered in the contemporary interpretation on the evaluation of ancient systems of the knowledge.

  7. Structural Evolution and Kinetics in Cu-Zr Metallic Liquids from Molecular Dynamics Simulations (Postprint)

    DTIC Science & Technology

    2013-10-23

    compensate for overcounting due to numerical issues inherent in the tessellation.16 The shape of the coordination polyhedron was determined by the shape...work by Yang et al.21 The total volume can be determined by finding the volume of the convex polyhedron whose vertices are given by the centers of...atoms in the nearest-neighbor shell. In order to determine the volume of the atoms inside the clusters, the convex hull polyhedron is first segmented

  8. Interstellar Explorer Observations of the Solar System's Debris Disks

    NASA Astrophysics Data System (ADS)

    Lisse, C. M.; McNutt, R. L., Jr.; Brandt, P. C.

    2017-12-01

    Planetesimal belts and debris disks full of dust are known as the "signposts of planet formation" in exosystems. The overall brightness of a disk provides information on the amount of sourcing planetesimal material, while asymmetries in the shape of the disk can be used to search for perturbing planets. The solar system is known to house two such belts, the Asteroid belt and the Kuiper Belt; and at least one debris cloud, the Zodiacal Cloud, sourced by planetisimal collisions and Kuiper Belt comet evaporative sublimation. However these are poorly understood in toto because we live inside of them. E.g., while we know of the two planetesimal belt systems, it is not clear how much, if any, dust is produced from the Kuiper belt since the near-Sun comet contributions dominate near-Earth space. Understanding how much dust is produced in the Kuiper belt would give us a much better idea of the total number of bodies in the belt, especially the smallest ones, and their dynamical collisional state. Even for the close in Zodiacal cloud, questions remain concerning its overall shape and orientation with respect to the ecliptic and invariable planes of the solar system - they aren't explainable from the perturbations caused by the known planets alone. In this paper we explore the possibilities of using an Interstellar Explorer telescope placed at 200 AU from the sun to observe the brightness, shape, and extent of the solar system's debris disk(s). We should be able to measure the entire extent of the inner, near-earth zodiacal cloud; whether it connects smoothly into an outer cloud, or if there is a second outer cloud sourced by the Kuiper belt and isolated by the outer planets, as predicted by Stark & Kuchner (2009, 2010) and Poppe et al. (2012, 2016; Figure 1). VISNIR imagery will inform about the dust cloud's density, while MIR cameras will provide thermal imaging photometry related to the cloud's dust particle size and composition. Observing at high phase angle by looking

  9. Nulling interferometry: impact of exozodiacal clouds on the performance of future life-finding space missions

    NASA Astrophysics Data System (ADS)

    Defrère, D.; Absil, O.; den Hartog, R.; Hanot, C.; Stark, C.

    2010-01-01

    Context. Earth-sized planets around nearby stars are being detected for the first time by ground-based radial velocity and space-based transit surveys. This milestone is opening the path toward the definition of instruments able to directly detect the light from these planets, with the identification of bio-signatures as one of the main objectives. In that respect, both the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) have identified nulling interferometry as one of the most promising techniques. The ability to study distant planets will however depend on the amount of exozodiacal dust in the habitable zone of the target stars. Aims: We assess the impact of exozodiacal clouds on the performance of an infrared nulling interferometer in the Emma X-array configuration. The first part of the study is dedicated to the effect of the disc brightness on the number of targets that can be surveyed and studied by spectroscopy during the mission lifetime. In the second part, we address the impact of asymmetric structures in the discs such as clumps and offset which can potentially mimic the planetary signal. Methods: We use the DarwinSIM software which was designed and validated to study the performance of space-based nulling interferometers. The software has been adapted to handle images of exozodiacal discs and to compute the corresponding demodulated signal. Results: For the nominal mission architecture with 2-m aperture telescopes, centrally symmetric exozodiacal dust discs about 100 times denser than the solar zodiacal cloud can be tolerated in order to survey at least 150 targets during the mission lifetime. Considering modeled resonant structures created by an Earth-like planet orbiting at 1 AU around a Sun-like star, we show that this tolerable dust density goes down to about 15 times the solar zodiacal density for face-on systems and decreases with the disc inclination. Conclusions: Whereas the disc brightness only affects

  10. Breakthrough Capability for the NASA Astrophysics Explorer Program: Reaching the Darkest Sky

    NASA Technical Reports Server (NTRS)

    Greenhouse, Matthew A.; Benson, Scott W.; Falck, Robert D.; Fixsen, Dale J.; Gardner, Joseph P.; Garvin, James B.; Kruk, Jeffrey W.; Oleson, Stephen R.; Thronson, Harley A.

    2012-01-01

    We describe a mission architecture designed to substantially increase the science capability of the NASA Science Mission Directorate (SMD) Astrophysics Explorer Program for all AO proposers working within the near-UV to far-infrared spectrum. We have demonstrated that augmentation of Falcon 9 Explorer launch services with a 13 kW Solar Electric Propulsion (SEP) stage can deliver a 700 kg science observatory payload to extra-Zodiacal orbit. This new capability enables up to 13X increased photometric sensitivity and 160X increased observing speed relative to a Sun- Earth L2, Earth-trailing, or Earth orbit with no increase in telescope aperture. All enabling SEP stage technologies for this launch service augmentation have reached sufficient readiness (TRL-6) for Explorer Program application in conjunction with the Falcon 9. We demonstrate that enabling Astrophysics Explorers to reach extra-zodiacal orbit will allow this small payload program to rival the science performance of much larger long development time systems; thus, providing a means to realize major science objectives while increasing the SMD Astrophysics portfolio diversity and resiliency to external budget pressure. The SEP technology employed in this study has strong applicability to SMD Planetary Science community-proposed missions. SEP is a stated flight demonstration priority for NASA's Office of the Chief Technologist (OCT). This new mission architecture for astrophysics Explorers enables an attractive realization of joint goals for OCT and SMD with wide applicability across SMD science disciplines.

  11. Breakthrough Capability for UVOIR Space Astronomy: Reaching the Darkest Sky

    NASA Technical Reports Server (NTRS)

    Greenhouse, Matthew A.; Benson, Scott W.; Englander, Jacob; Falck, Robert D.; Fixsen, Dale J.; Gardner, Jonathan P.; Kruk, Jeffrey W.; Oleson, Steven R.; Thronson, Harley A.

    2014-01-01

    We describe how availability of new solar electric propulsion (SEP) technology can substantially increase the science capability of space astronomy missions working within the near-UV to far-infrared (UVOIR) spectrum by making dark sky orbits accessible for the first time. We present a proof of concept case study in which SEP is used to enable a 700 kg Explorer-class observatory payload to reach an orbit beyond where the zodiacal dust limits observatory sensitivity. The resulting scientific performance advantage relative to a Sun-Earth L2 point orbit is presented and discussed. We find that making SEP available to astrophysics Explorers can enable this small payload program to rival the science performance of much larger long development-time systems. We also present flight dynamics analysis which illustrates that this concept can be extended beyond Explorers to substantially improve the sensitivity performance of heavier (7000 kg) flagship-class astrophysics payloads such as the UVOIR successor to the James Webb Space Telescope by using high power SEP that is being developed for the Asteroid Redirect Robotics Mission.

  12. Full kinetics of CO entry, internal diffusion, and exit in myoglobin from transition-path theory simulations.

    PubMed

    Yu, Tang-Qing; Lapelosa, Mauro; Vanden-Eijnden, Eric; Abrams, Cameron F

    2015-03-04

    We use Markovian milestoning molecular dynamics (MD) simulations on a tessellation of the collective variable space for CO localization in myoglobin to estimate the kinetics of entry, exit, and internal site-hopping. The tessellation is determined by analysis of the free-energy surface in that space using transition-path theory (TPT), which provides criteria for defining optimal milestones, allowing short, independent, cell-constrained MD simulations to provide properly weighted kinetic data. We coarse grain the resulting kinetic model at two levels: first, using crystallographically relevant internal cavities and their predicted interconnections and solvent portals; and second, as a three-state side-path scheme inspired by similar models developed from geminate recombination experiments. We show semiquantitative agreement with experiment on entry and exit rates and in the identification of the so-called "histidine gate" at position 64 through which ≈90% of flux between solvent and the distal pocket passes. We also show with six-dimensional calculations that the minimum free-energy pathway of escape through the histidine gate is a "knock-on" mechanism in which motion of the ligand and the gate are sequential and interdependent. In total, these results suggest that such TPT simulations are indeed a promising approach to overcome the practical time-scale limitations of MD to allow reliable estimation of transition mechanisms and rates among metastable states.

  13. Day 3 on the USS Anchorage for the Recovery of Orion

    NASA Image and Video Library

    2014-12-03

    On the third day of preparations for recovery of Orion, U.S. Navy divers in two rigid hull inflatable boats and two Zodiac boats practice recovery procedures nearby the USS Anchorage in the Pacific Ocean about 600 miles off the coast of Baja, California. NASA, Lockheed Martin and U.S. Navy personnel are preparing for recovery of the Orion crew module, forward bay cover and parachutes after its return from space and splashdown in the Pacific Ocean. The Ground Systems Development and Operations Program is leading the recovery efforts.

  14. Day 3 on the USS Anchorage for the Recovery of Orion

    NASA Image and Video Library

    2014-12-03

    On the third day of preparations for recovery of Orion after its splashdown in the Pacific Ocean, U.S. Navy Divers prepare to embark from the well deck of the USS Anchorage in a rigid hull Zodiac boat about 600 miles off the coast of Baja, California. NASA, Lockheed Martin and U.S. Navy personnel are preparing for recovery of the crew module, forward bay cover and parachutes on its return from space and splashdown in the Pacific Ocean. The Ground Systems Development and Operations Program is leading the recovery efforts.

  15. Day 3 on the USS Anchorage for the Recovery of Orion

    NASA Image and Video Library

    2014-12-03

    On the third day of preparations for recovery of Orion after its splashdown in the Pacific Ocean, U.S. Navy Divers prepare to embark from the well deck of the USS Anchorage in two rigid hull Zodiac boats about 600 miles off the coast of Baja, California. NASA, Lockheed Martin and U.S. Navy personnel are preparing for recovery of the crew module, forward bay cover and parachutes on its return from space and splashdown in the Pacific Ocean. The Ground Systems Development and Operations Program is leading the recovery efforts.

  16. Cosmic dust in the atmosphere and in the interplanetary space at 1 AU today and in the early solar system

    NASA Technical Reports Server (NTRS)

    Fechtig, H.

    1973-01-01

    A description of techniques used in recent experiments to detect and analyze cosmic dust and micrometeorites is given and the results both from the study of lunar crater statistics and from in situ measurements are reviewed. The results from lunar crater statistics show an agreement with the results obtained from in situ measurements in interplanetary space and derived from zodiacal light measurements. The near earth results show an enhancement in the flux numbers. This can be caused either by secondary lunar debris or by disintegration of low density fireballs in the outer atmosphere.

  17. Sex preferences and fertility in South Korea during the year of the Horse.

    PubMed

    Lee, Jungmin; Paik, Myungho

    2006-05-01

    Since antiquity, people in several East Asian countries, such as China, Japan, and South Korea, have believed that a person is destined to possess specific characteristics according to the sign of the zodiac under which he or she was born. South Koreans, in particular, have traditionally considered that the year of the Horse bears inauspicious implications for the birth of daughters. Using monthly longitudinal data at the region level in South Korea between 1970 and 2003, we found that in the year of the Horse, the sex ratio at birth significantly increased while fertility decreased.

  18. Cosmic dust and space debris; Proceedings of the Topical Meetings and Workshop 6 of the 26th COSPAR Plenary Meeting, Toulouse, France, June 30-July 11, 1986

    NASA Technical Reports Server (NTRS)

    Mcdonnell, J. A. M. (Editor); Hanner, M. S. (Editor); Kessler, D. J. (Editor)

    1986-01-01

    These proceedings encompass topics in the fields of extraterrestrial material samples, IRAS solar system and dust model results, and earth orbit debris. Attention is given to chemical fractionation during high velocity impact, particle deceleration and survival in multiple thin foil targets, and IRAS studies of asteroids, comets, cometary tails, the zodiacal background, and the three-dimensional modeling of interplanetary dust. Also discussed are the evolution of an earth orbit debris cloud, orbital debris due to future space activities, collision probabilities in geosynchronous orbits, and a bitelescopic survey of low altitude orbital debris.

  19. Scattering by ensembles of small particles experiment, theory and application

    NASA Technical Reports Server (NTRS)

    Gustafson, B. A. S.

    1980-01-01

    A hypothetical self consistent picture of evolution of prestellar intertellar dust through a comet phase leads to predictions about the composition of the circum-solar dust cloud. Scattering properties of thus resulting conglomerates with a bird's-nest type of structure are investigated using a micro-wave analogue technique. Approximate theoretical methods of general interest are developed which compared favorably with the experimental results. The principal features of scattering of visible radiation by zodiacal light particles are reasonably reproduced. A component which is suggestive of (ALPHA)-meteoroids is also predicted.

  20. Intelligent Mobile Autonomous System (IMAS).

    DTIC Science & Technology

    1987-01-01

    the "tile" of tesselation at a level (grain, discrete, pixel, or voxel of the space). These terms can be used intermittently , and each of them...search on the original level of traversability space is not fast enough to be considered for actual control application. Alternatives to limit the...0 (b) It must be concise and easy to "compute". In other words there must exist simple, fast procedures for instantiating the "words" or "sentences

  1. HiPS - Hierarchical Progressive Survey Version 1.0

    NASA Astrophysics Data System (ADS)

    Fernique, Pierre; Allen, Mark; Boch, Thomas; Donaldson, Tom; Durand, Daniel; Ebisawa, Ken; Michel, Laurent; Salgado, Jesus; Stoehr, Felix; Fernique, Pierre

    2017-05-01

    This document presents HiPS, a hierarchical scheme for the description, storage and access of sky survey data. The system is based on hierarchical tiling of sky regions at finer and finer spatial resolution which facilitates a progressive view of a survey, and supports multi-resolution zooming and panning. HiPS uses the HEALPix tessellation of the sky as the basis for the scheme and is implemented as a simple file structure with a direct indexing scheme that leads to practical implementations.

  2. Custom-Made Pyramids.

    DTIC Science & Technology

    1986-11-01

    V2 + V 2 2 We can formulate the general weighted resampling formulas by giving an inter - polation formula and a sampling formula. Specifically...tessellation grids. 4.1. One-dimensional Adaptive Pyramid We suggest an interest operator based on the local " busyness " of the data. It has been observed...that in human perception a line with higher " busyness " seems longer than a straight line segment [6], as in Figure 7. Here, we will use a smoothed

  3. Fixation of CO2 in bi-layered coordination networks of zinc tetra(4-carboxyphenyl)porphyrin with multi-component [Pr2Na3(NO3)(H2O)3] connectors.

    PubMed

    Nandi, Goutam; Goldberg, Israel

    2014-11-14

    CO2 is fixed in a rare μ2-η bridging mode by bi-layered coordination networks of ZnTCPP tessellated along the four equatorial directions by [Pr2Na3(NO3)(H2O)3](8+) connecting clusters in a 2 : 1 ratio (1), but not in the isomorphous free-base porphyrin analogue [(TCPPH2)2(Pr2Na3(NO3)(H2O)3)]n (2), revealing the crucial role of the zinc metal in this process.

  4. Objective evaluation of choroidal melanin contents with polarization-sensitive optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Miura, Masahiro; Makita, Shuichi; Yasuno, Yoshiaki; Ikuno, Yasushi; Uematsu, Sato; Iwasaki, Takuya; Goto, Hiroshi

    2018-02-01

    We non-invasively evaluated choroidal melanin contents in human eyes with PS-OCT. We calculated the percentage area of low DOPU in the choroidal interstitial stroma for Vogt-Koyanagi- Harada disease with sunset glow fundus, without sunset glow fundus, control group and tessellated fundus with high myopia. The mean percentage area of low DOPU in the sunset group was significantly lower than the other groups. PS-OCT provides an in vivo objective evaluation of choroidal melanin loss in vivo human eyes.

  5. VizieR Online Data Catalog: New standards in 18th century astrometry (Lequeux, 2014)

    NASA Astrophysics Data System (ADS)

    Lequeux, J.

    2014-05-01

    named lacaillefund.dat. La Caille's complete survey of the southern sky (lacaisur.dat): During his stay in Cape Town in 1751-1752, La Caille made the first systematic survey of the sky ever, in the modern sense. 244 stars over 9766. La Caille's catalogue of zodiacal stars (lacaizod.dat): When La Caille returned from his southern expedition in 1754, he undertook the construction of a catalogue of zodiacal stars. Mayer's zodiacal catalogue (mayer.dat): At exactly the same time as La Caille, Tobias Mayer (1723-1762) in Gottingen undertook a similar catalogue of zodiacal stars, using a 6-feet radius mural quadrant made by John Bird (1709-1776). 200 stars over 998. Bradley's stellar catalogue (bradley.dat): James Bradley (1693-1762) is famous for his discovery of aberration and nutation. From 1750 to his death in 1762, he built a large stellar catalogue, from observations first with an old mural sector and after 1753 with the Bird 8-ft mural sector located in Greenwich, where it 215 stars over 3220. Piazzi's stellar catalogue (piazzi.dat): Giuseppe Piazzi (1746-1846) built a large catalogue containing 7646 stars from 1792 to 1813, observed in Palermo with an altazimuthal circle of Jesse Ramsden (1735-1800) can still be seen. 202 stars over 7646. Lalande's stellar catalogue (lalande.dat): L'Histoire celeste francaise de Lalande (Lalande 1801), which contains the unreduced observations of approximately 40,000 stars, is the first very large stellar catalogue. 198 stars over ~45000. (10 data files).

  6. Astronomical photography. Part A: Gum nebula, galactic cluster, and zodiacal light photography

    NASA Technical Reports Server (NTRS)

    Mercer, R. D.; Dunkelman, L.; Mattingly, T. K.

    1972-01-01

    It is reported that the Apollo 16 command module astronomical photography was performed with the specific objective of capitalizing on the uniqueness of the double umbra as a vantage point to collect astronomical data that are obtainable only near our Moon. For this reason, these data will be compared directly to analogous photography performed from Earth orbit during Project Mercury and the Gemini Program as well as to the Apollo-duplicated photography taken from sites on the Earth surface. Comparison with Earth-based photography should yield direct information on the Earth airglow layer and on atmospheric scattering and extinction.

  7. The Constellations of the Zodiac: Astronomy for Low Vision and Blind People

    NASA Astrophysics Data System (ADS)

    Garcia, B.; Cicero, A.; Farrando, M.; Bruno, P.

    2006-08-01

    One thinks, in general, there exist areas of the knowledge to which it is not possible to be acceded if one of the senses is diminished. Nevertheless, the reality is far from this false concept: it is not necessary to hear to compose music, nor to see to come near to the starred sky. This book has the purpose to introduce to the readers with visual difficulties the amazing world of astronomy, by means of the transmission of basic concepts of positional astronomy (cardinal points, Earth movements, apparent movement of the celestial sphere), with special emphasis in: movement of precession, the concept of stellar magnitude, its representation in celestial charts, and relation to mythology. On the other hand, the figures associated with the 13 constellations in the region of the plane of the ecliptic are described. The texts and the images are displayed in two formats: for visually diminished people, one worked on the basis of the original engravings of the Uranographia by Hevelius (1690). These were adapted and simplified for their better understanding, and a recommended font size. For blind people, we use tactile feature for the figures and Braille for the text.

  8. Mass reduction patterning of silicon-on-oxide-based micromirrors

    NASA Astrophysics Data System (ADS)

    Hall, Harris J.; Green, Andrew; Dooley, Sarah; Schmidt, Jason D.; Starman, LaVern A.; Langley, Derrick; Coutu, Ronald A.

    2016-10-01

    It has long been recognized in the design of micromirror-based optical systems that balancing static flatness of the mirror surface through structural design with the system's mechanical dynamic response is challenging. Although a variety of mass reduction approaches have been presented in the literature to address this performance trade, there has been little quantifiable comparison reported. In this work, different mass reduction approaches, some unique to the work, are quantifiably compared with solid plate thinning in both curvature and mass using commercial finite element simulation of a specific square silicon-on-insulator-based micromirror geometry. Other important considerations for micromirror surfaces, including surface profile and smoothness, are also discussed. Fabrication of one of these geometries, a two-dimensional tessellated square pattern, was performed in the presence of a 400-μm-tall central post structure using a simple single mask process. Limited experimental curvature measurements of fabricated samples are shown to correspond well with properly characterized simulation results and indicate ˜67% improvement in radius of curvature in comparison to a solid plate design of equivalent mass.

  9. The R package 'icosa' for coarse resolution global triangular and penta-hexagonal gridding

    NASA Astrophysics Data System (ADS)

    Kocsis, Adam T.

    2017-04-01

    With the development of the internet and the computational power of personal computers, open source programming environments have become indispensable for science in the past decade. This includes the increase of the GIS capacity of the free R environment, which was originally developed for statistical analyses. The flexibility of R made it a preferred programming tool in a multitude of disciplines from the area of the biological and geological sciences. Many of these subdisciplines operate with incidence (occurrence) data that are in a large number of cases to be grained before further analyses can be conducted. This graining is executed mostly by gridding data to cells of a Gaussian grid of various resolutions to increase the density of data in a single unit of the analyses. This method has obvious shortcomings despite the ease of its application: well-known systematic biases are induced to cell sizes and shapes that can interfere with the results of statistical procedures, especially if the number of incidence points influences the metrics in question. The 'icosa' package employs a common method to overcome this obstacle by implementing grids with roughly equal cell sizes and shapes that are based on tessellated icosahedra. These grid objects are essentially polyhedra with xyz Cartesian vertex data that are linked to tables of faces and edges. At its current developmental stage, the package uses a single method of tessellation which balances grid cell size and shape distortions, but its structure allows the implementation of various other types of tessellation algorithms. The resolution of the grids can be set by the number of breakpoints inserted into a segment forming an edge of the original icosahedron. Both the triangular and their inverted penta-hexagonal grids are available for creation with the package. The package also incorporates functions to look up coordinates in the grid very effectively and data containers to link data to the grid structure. The

  10. The Application of the Montage Image Mosaic Engine To The Visualization Of Astronomical Images

    NASA Astrophysics Data System (ADS)

    Berriman, G. Bruce; Good, J. C.

    2017-05-01

    The Montage Image Mosaic Engine was designed as a scalable toolkit, written in C for performance and portability across *nix platforms, that assembles FITS images into mosaics. This code is freely available and has been widely used in the astronomy and IT communities for research, product generation, and for developing next-generation cyber-infrastructure. Recently, it has begun finding applicability in the field of visualization. This development has come about because the toolkit design allows easy integration into scalable systems that process data for subsequent visualization in a browser or client. The toolkit it includes a visualization tool suitable for automation and for integration into Python: mViewer creates, with a single command, complex multi-color images overlaid with coordinate displays, labels, and observation footprints, and includes an adaptive image histogram equalization method that preserves the structure of a stretched image over its dynamic range. The Montage toolkit contains functionality originally developed to support the creation and management of mosaics, but which also offers value to visualization: a background rectification algorithm that reveals the faint structure in an image; and tools for creating cutout and downsampled versions of large images. Version 5 of Montage offers support for visualizing data written in HEALPix sky-tessellation scheme, and functionality for processing and organizing images to comply with the TOAST sky-tessellation scheme required for consumption by the World Wide Telescope (WWT). Four online tutorials allow readers to reproduce and extend all the visualizations presented in this paper.

  11. Numerical fatigue 3D-FE modeling of indirect composite-restored posterior teeth.

    PubMed

    Ausiello, Pietro; Franciosa, Pasquale; Martorelli, Massimo; Watts, David C

    2011-05-01

    In restored teeth, stresses at the tooth-restoration interface during masticatory processes may fracture the teeth or the restoration and cracks may grow and propagate. The aim was to apply numerical methodologies to simulate the behavior of a restored tooth and to evaluate fatigue lifetimes before crack failure. Using a CAD-FEM procedure and fatigue mechanic laws, the fatigue damage of a restored molar was numerically estimated. Tessellated surfaces of enamel and dentin were extracted by applying segmentation and classification algorithms, to sets of 2D image data. A user-friendly GUI, which enables selection and visualization of 3D tessellated surfaces, was developed in a MatLab(®) environment. The tooth-boundary surfaces of enamel and dentin were then created by sweeping operations through cross-sections. A class II MOD cavity preparation was then added into the 3D model and tetrahedral mesh elements were generated. Fatigue simulation was performed by combining a preliminary static FEA simulation with classical fatigue mechanical laws. Regions with the shortest fatigue-life were located around the fillets of the class II MOD cavity, where the static stress was highest. The described method can be successfully adopted to generate detailed 3D-FE models of molar teeth, with different cavities and restorative materials. This method could be quickly implemented for other dental or biomechanical applications. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  12. Fabric and connectivity as field descriptors for deformations in granular media

    NASA Astrophysics Data System (ADS)

    Wan, Richard; Pouragha, Mehdi

    2015-01-01

    Granular materials involve microphysics across the various scales giving rise to distinct behaviours of geomaterials, such as steady states, plastic limit states, non-associativity of plastic and yield flow, as well as instability of homogeneous deformations through strain localization. Incorporating such micro-scale characteristics is one of the biggest challenges in the constitutive modelling of granular materials, especially when micro-variables may be interdependent. With this motivation, we use two micro-variables such as coordination number and fabric anisotropy computed from tessellation of the granular material to describe its state at the macroscopic level. In order to capture functional dependencies between micro-variables, the correlation between coordination number and fabric anisotropy limits is herein formulated at the particle level rather than on an average sense. This is the essence of the proposed work which investigates the evolutions of coordination number distribution (connectivity) and anisotropy (contact normal) distribution curves with deformation history and their inter-dependencies through discrete element modelling in two dimensions. These results enter as probability distribution functions into homogenization expressions during upscaling to a continuum constitutive model using tessellation as an abstract representation of the granular system. The end product is a micro-mechanically inspired continuum model with both coordination number and fabric anisotropy as underlying micro-variables incorporated into a plasticity flow rule. The derived plastic potential bears striking resemblance to cam-clay or stress-dilatancy-type yield surfaces used in soil mechanics.

  13. 3D modeling to characterize lamina cribrosa surface and pore geometries using in vivo images from normal and glaucomatous eyes

    PubMed Central

    Sredar, Nripun; Ivers, Kevin M.; Queener, Hope M.; Zouridakis, George; Porter, Jason

    2013-01-01

    En face adaptive optics scanning laser ophthalmoscope (AOSLO) images of the anterior lamina cribrosa surface (ALCS) represent a 2D projected view of a 3D laminar surface. Using spectral domain optical coherence tomography images acquired in living monkey eyes, a thin plate spline was used to model the ALCS in 3D. The 2D AOSLO images were registered and projected onto the 3D surface that was then tessellated into a triangular mesh to characterize differences in pore geometry between 2D and 3D images. Following 3D transformation of the anterior laminar surface in 11 normal eyes, mean pore area increased by 5.1 ± 2.0% with a minimal change in pore elongation (mean change = 0.0 ± 0.2%). These small changes were due to the relatively flat laminar surfaces inherent in normal eyes (mean radius of curvature = 3.0 ± 0.5 mm). The mean increase in pore area was larger following 3D transformation in 4 glaucomatous eyes (16.2 ± 6.0%) due to their more steeply curved laminar surfaces (mean radius of curvature = 1.3 ± 0.1 mm), while the change in pore elongation was comparable to that in normal eyes (−0.2 ± 2.0%). This 3D transformation and tessellation method can be used to better characterize and track 3D changes in laminar pore and surface geometries in glaucoma. PMID:23847739

  14. GPU-accelerated depth map generation for X-ray simulations of complex CAD geometries

    NASA Astrophysics Data System (ADS)

    Grandin, Robert J.; Young, Gavin; Holland, Stephen D.; Krishnamurthy, Adarsh

    2018-04-01

    Interactive x-ray simulations of complex computer-aided design (CAD) models can provide valuable insights for better interpretation of the defect signatures such as porosity from x-ray CT images. Generating the depth map along a particular direction for the given CAD geometry is the most compute-intensive step in x-ray simulations. We have developed a GPU-accelerated method for real-time generation of depth maps of complex CAD geometries. We preprocess complex components designed using commercial CAD systems using a custom CAD module and convert them into a fine user-defined surface tessellation. Our CAD module can be used by different simulators as well as handle complex geometries, including those that arise from complex castings and composite structures. We then make use of a parallel algorithm that runs on a graphics processing unit (GPU) to convert the finely-tessellated CAD model to a voxelized representation. The voxelized representation can enable heterogeneous modeling of the volume enclosed by the CAD model by assigning heterogeneous material properties in specific regions. The depth maps are generated from this voxelized representation with the help of a GPU-accelerated ray-casting algorithm. The GPU-accelerated ray-casting method enables interactive (> 60 frames-per-second) generation of the depth maps of complex CAD geometries. This enables arbitrarily rotation and slicing of the CAD model, leading to better interpretation of the x-ray images by the user. In addition, the depth maps can be used to aid directly in CT reconstruction algorithms.

  15. Heavenly Bodies and Phenomena in Petroglyphs

    NASA Astrophysics Data System (ADS)

    Tokhatyan, Karen

    2016-12-01

    In Armenian culture are amply reflected realities connected with Universe. Their figurative expressions are also petroglyphs in which there are representations of solar signs, swastika, Moon crescend, planets, stars, star groups, constellations, Milky Way, Earth. Among heavenly and atmospheric phenomena are: eclipce, meteor, comet, ligthning, cloud, rain and rainbow. There are many products of scientific thinking: stellar maps, calendars, compasses, astronomical records, Zodiac signs and ideograms. Thousands of the Armenian petroglyphs that were created millennia ago by an indigenous ethnos - Armenians, point to the significant place of celestial bodies and luminaries, especially the Sun, stars, and stellar constellations in our ancestors' cosmological perceptions.

  16. Orion Splashdown Recovery

    NASA Image and Video Library

    2014-12-05

    NASA's Orion spacecraft splashed down in the Pacific Ocean after its first flight test atop a Delta IV Heavy rocket from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida. U.S. Navy divers in Zodiac boats prepare to recover Orion and tow her in to the well deck of the USS Anchorage. NASA's Orion spacecraft completed a two-orbit, four-and-a-half hour mission to test systems critical to crew safety, including the launch abort system, the heat shield and the parachute system. The Ground Systems Development and Operations Program is leading the recovery efforts.

  17. Day 3 on the USS Anchorage for the Recovery of Orion

    NASA Image and Video Library

    2014-12-03

    On the third day of preparations for recovery of Orion after its splashdown in the Pacific Ocean, the well deck of the USS Anchorage has been filled with water and recovery hardware is in place. U.S. Navy divers have embarked from ship to practice recovery procedures in rigid hull inflatable boats and Zodiac boats. NASA, Lockheed Martin and U.S. Navy personnel are preparing for recovery of the crew module, forward bay cover and parachutes on its return from space and splashdown in the Pacific Ocean. The Ground Systems Development and Operations Program is leading the recovery efforts.

  18. 'For the benefit of the people': the Dutch translation of the Fasciculus medicinae, Antwerp 1512.

    PubMed

    Coppens, Christian

    2009-01-01

    The article deals with the Dutch translation of the Fasciculus medicinae based on the Latin edition, Venice 1495, with the famous woodcuts created in 1494 for the Italian translation of the original Latin edition of 1491. The woodcuts are compared with the Venetian model. New features in the Antwerp edition include the Skeleton and the Zodiac Man, bot originally based on German models. The text also deals with other woodcuts in the Low Countries based on these Venetian illustrations. The Appendices provide a short title catalog of all the editions and translations based on the Venetian edition and a stemma.

  19. Astrophysical dust grains in stars, the interstellar medium, and the solar system

    NASA Technical Reports Server (NTRS)

    Gehrz, Robert D.

    1991-01-01

    Studies of astrophysical dust grains in circumstellar shells, the interstellar medium, and the solar system may provide information about stellar evolution and about physical conditions in the primitive solar nebula. The following subject areas are covered: (1) the cycling of dust in stellar evolution and the formation of planetary systems; (2) astrophysical dust grains in circumstellar environments; (3) circumstellar grain formation and mass loss; (4) interstellar dust grains; (5) comet dust and the zodiacal cloud; (6) the survival of dust grains during stellar evolution; and (7) establishing connections between stardust and dust in the solar system.

  20. Comparing highly ordered monolayers of nanoparticles fabricated using electrophoretic deposition: Cobalt ferrite nanoparticles versus iron oxide nanoparticles

    DOE PAGES

    Dickerson, James H.; Krejci, Alex J.; Garcia, Adriana -Mendoza; ...

    2015-08-01

    Ordered assemblies of nanoparticles remain challenging to fabricate, yet could open the door to many potential applications of nanomaterials. Here, we demonstrate that locally ordered arrays of nanoparticles, using electrophoretic deposition, can be extended to produce long-range order among the constituents. Voronoi tessellations along with multiple statistical analyses show dramatic increases in order compared with previously reported assemblies formed through electric field-assisted assembly. As a result, based on subsequent physical measurements of the nanoparticles and the deposition system, the underlying mechanisms that generate increased order are inferred.

  1. Obituary: Elizabeth Katherine Holmes, 1973-2004

    NASA Astrophysics Data System (ADS)

    Beichman, Charles Arnold

    2004-12-01

    Elizabeth (Beth) K. Holmes died suddenly in Pasadena on March 23, 2004, from the unexpected effects of a long-standing heart condition. She was 30 years old. At the moment of her passing, she was at her computer comparing her theoretical models on the effects of planets on the distribution of zodiacal dust with some of the first observations from the Spitzer Space Telescope. Born on June 24, 1973, in New York City, Beth was the only child of James and Barbara Holmes, who were respectively, a financial manager and a nurse and social worker. Undeterred by numerous treatments and operations to correct a congenital heart condition, Beth developed an interest in math and physics leading to her graduation from MIT in 1995 with a bachelor's degree in Physics. She entered the University of Florida shortly afterwards to begin her PhD studies under the direction of Stanley Dermott. Beth was particularly interested in the dynamics of interplanetary dust, and initially worked on secular perturbations of the zodiacal cloud: how the planets impose warping of the cloud, and how they can force the center of the cloud to be offset from the Sun. Despite the fact that Beth was primarily a theorist, she was keen to include some observing experience in her PhD education. She recently completed an observing program with Harold Butner at the Steward and Palomar Observatories looking for submillimeter and mid-infrared emission around nearby main-sequence stars - a signpost of planetary formation. The results were published last year in the Astronomical Journal. Beth's PhD thesis work, some results of which were recently published in the Astrophysical Journal, focused on dust originating in the Kuiper belt and how some of this dust is expected to be spatially structured due to resonant interactions with Neptune. This phenomenon may be quite common in other planetary systems, with recent images of Epsilon Eridani perhaps providing a prime example of a Kuiper disk analog. After graduating

  2. The Wide-Field Infrared Survey Explorer (WISE): Mission Description and Initial On-Orbit Performance

    NASA Technical Reports Server (NTRS)

    Wright, Edward L.; Eisenhardt, Peter R. M.; Mainzer, Amy; Ressler, Michael E.; Cutri, Roc M.; Jarrett, Thomas; Kirkpatrick, J. Davy; Padgett, Deborah; McMillan, Robert S.; Skrutskie,Michael; hide

    2010-01-01

    The all sky surveys done by the Palomar Observatory Schmidt, the European Southern Observatory Schmidt, and the United Kingdom Schmidt, the InfraRed Astronomical Satellite and the 2 Micron All Sky Survey have proven to be extremely useful tools for astronomy with value that lasts for decades. The Wide-field Infrared Survey Explorer is mapping the whole sky following its launch on 14 December 2009. WISE began surveying the sky on 14 Jan 2010 and completed its first full coverage of the sky on July 17. The survey will continue to cover the sky a second time until the cryogen is exhausted (anticipated in November 2010). WISE is achieving 5 sigma point source sensitivities better than 0.08, 0.11, 1 and 6 mJy in unconfused regions on the ecliptic in bands centered at wavelengths of 3.4, 4.6, 12 and 22 micrometers. Sensitivity improves toward the ecliptic poles due to denser coverage and lower zodiacal background. The angular resolution is 6.1", 6.4", 6.5" and 12.0" at 3.4, 4.6, 12 and 22 micrometers, and the astrometric precision for high SNR sources is better than 0.15".

  3. A new approach to simulating collisionless dark matter fluids

    NASA Astrophysics Data System (ADS)

    Hahn, Oliver; Abel, Tom; Kaehler, Ralf

    2013-09-01

    Recently, we have shown how current cosmological N-body codes already follow the fine grained phase-space information of the dark matter fluid. Using a tetrahedral tessellation of the three-dimensional manifold that describes perfectly cold fluids in six-dimensional phase space, the phase-space distribution function can be followed throughout the simulation. This allows one to project the distribution function into configuration space to obtain highly accurate densities, velocities and velocity dispersions. Here, we exploit this technique to show first steps on how to devise an improved particle-mesh technique. At its heart, the new method thus relies on a piecewise linear approximation of the phase-space distribution function rather than the usual particle discretization. We use pseudo-particles that approximate the masses of the tetrahedral cells up to quadrupolar order as the locations for cloud-in-cell (CIC) deposit instead of the particle locations themselves as in standard CIC deposit. We demonstrate that this modification already gives much improved stability and more accurate dynamics of the collisionless dark matter fluid at high force and low mass resolution. We demonstrate the validity and advantages of this method with various test problems as well as hot/warm dark matter simulations which have been known to exhibit artificial fragmentation. This completely unphysical behaviour is much reduced in the new approach. The current limitations of our approach are discussed in detail and future improvements are outlined.

  4. Stochastic transformation of points in polygons according to the Voronoi tessellation: microstructural description.

    PubMed

    Di Vito, Alessia; Fanfoni, Massimo; Tomellini, Massimo

    2010-12-01

    Starting from a stochastic two-dimensional process we studied the transformation of points in disks and squares following a protocol according to which at any step the island size increases proportionally to the corresponding Voronoi tessera. Two interaction mechanisms among islands have been dealt with: coalescence and impingement. We studied the evolution of the island density and of the island size distribution functions, in dependence on island collision mechanisms for both Poissonian and correlated spatial distributions of points. The island size distribution functions have been found to be invariant with the fraction of transformed phase for a given stochastic process. The n(Θ) curve describing the island decay has been found to be independent of the shape (apart from high correlation degrees) and interaction mechanism.

  5. DICE/ColDICE: 6D collisionless phase space hydrodynamics using a lagrangian tesselation

    NASA Astrophysics Data System (ADS)

    Sousbie, Thierry

    2018-01-01

    DICE is a C++ template library designed to solve collisionless fluid dynamics in 6D phase space using massively parallel supercomputers via an hybrid OpenMP/MPI parallelization. ColDICE, based on DICE, implements a cosmological and physical VLASOV-POISSON solver for cold systems such as dark matter (CDM) dynamics.

  6. Engaging Preservice Teachers and Elementary-Age Children in Transformational Geometry: Tessellating T-Shirts

    ERIC Educational Resources Information Center

    Shockey, Tod L.; Snyder, Karen

    2007-01-01

    The Maine Learning Results (MLR) expects the state's students in prekindergarten through grade 2 to describe two-dimensional shapes as well as use positional language. Requiring translations of two-dimensional shapes supports this expectation. Students in grades 3-4 are expected to "use transformations," while students in grade 5-8 are…

  7. VoroMQA: Assessment of protein structure quality using interatomic contact areas.

    PubMed

    Olechnovič, Kliment; Venclovas, Česlovas

    2017-06-01

    In the absence of experimentally determined protein structure many biological questions can be addressed using computational structural models. However, the utility of protein structural models depends on their quality. Therefore, the estimation of the quality of predicted structures is an important problem. One of the approaches to this problem is the use of knowledge-based statistical potentials. Such methods typically rely on the statistics of distances and angles of residue-residue or atom-atom interactions collected from experimentally determined structures. Here, we present VoroMQA (Voronoi tessellation-based Model Quality Assessment), a new method for the estimation of protein structure quality. Our method combines the idea of statistical potentials with the use of interatomic contact areas instead of distances. Contact areas, derived using Voronoi tessellation of protein structure, are used to describe and seamlessly integrate both explicit interactions between protein atoms and implicit interactions of protein atoms with solvent. VoroMQA produces scores at atomic, residue, and global levels, all in the fixed range from 0 to 1. The method was tested on the CASP data and compared to several other single-model quality assessment methods. VoroMQA showed strong performance in the recognition of the native structure and in the structural model selection tests, thus demonstrating the efficacy of interatomic contact areas in estimating protein structure quality. The software implementation of VoroMQA is freely available as a standalone application and as a web server at http://bioinformatics.lt/software/voromqa. Proteins 2017; 85:1131-1145. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  8. GEMINI- INSIGNIA - SPACE PROGRAM - MSC

    NASA Image and Video Library

    1965-08-30

    S65-54354 (30 Aug. 1965) --- The insignia of the Gemini Space Program is a disc of dark blue as a background for a gold Zodiac Gemini symbol. A white star on each of the two vertical curves of the Gemini symbol represent the Gemini twins, Pollux and Castor. The NASA insignia design for Gemini flights is reserved for use by the astronauts and for other official use as the NASA Administrator may authorize. Public availability has been approved only in the form of illustrations by the various news media. When and if there is any change in this policy, which we do not anticipate, it will be publicly announced.

  9. WFIRST: Coronagraph Systems Engineering and Performance Budgets

    NASA Astrophysics Data System (ADS)

    Poberezhskiy, Ilya; cady, eric; Frerking, Margaret A.; Kern, Brian; Nemati, Bijan; Noecker, Martin; Seo, Byoung-Joon; Zhao, Feng; Zhou, Hanying

    2018-01-01

    The WFIRST coronagraph instrument (CGI) will be the first in-space coronagraph using active wavefront control to directly image and characterize mature exoplanets and zodiacal disks in reflected starlight. For CGI systems engineering, including requirements development, CGI performance is predicted using a hierarchy of performance budgets to estimate various noise components — spatial and temporal flux variations — that obscure exoplanet signals in direct imaging and spectroscopy configurations. These performance budgets are validated through a robust integrated modeling and testbed model validation efforts.We present the performance budgeting framework used by WFIRST for the flow-down of coronagraph science requirements, mission constraints, and observatory interfaces to measurable instrument engineering parameters.

  10. On-Orbit Sky Background Measurements with the FOS

    NASA Technical Reports Server (NTRS)

    Lyons, R. W.; Baity, W. A.; Beaver, E. A.; Cohen, R. D.; Junkkarinen, V. T.; Linsky, J. B.; Bohlin, R. C.

    1993-01-01

    Observations of the sky background obtained with the Faint Object Spectrograph during 1991-1992 are discussed. Sky light can be an important contributor to the observed count rate in several of the instrument configurations especially when large apertures are used. In general, the sky background is consistent with the pre-launch expectations and showed the expected effects of zodiacal light and diffuse galactic light. In addition to these sources, there is, particularly during the daytime, a highly variable airglow component which includes a number of emission lines. The sky background will have an impact on the reduction and possibly the interpretation of some spectra.

  11. Zodiacal Exoplanets in Time (ZEIT). IV. Seven Transiting Planets in the Praesepe Cluster

    NASA Astrophysics Data System (ADS)

    Mann, Andrew W.; Gaidos, Eric; Vanderburg, Andrew; Rizzuto, Aaron C.; Ansdell, Megan; Medina, Jennifer Vanessa; Mace, Gregory N.; Kraus, Adam L.; Sokal, Kimberly R.

    2017-02-01

    Open clusters and young stellar associations are attractive sites to search for planets and to test theories of planet formation, migration, and evolution. We present our search for, and characterization of, transiting planets in the 800 Myr old Praesepe (Beehive, M44) Cluster from K2 light curves. We identify seven planet candidates, six of which we statistically validate to be real planets, the last of which requires more data. For each host star, we obtain high-resolution NIR spectra to measure its projected rotational broadening and radial velocity, the latter of which we use to confirm cluster membership. We combine low-resolution spectra with the known cluster distance and metallicity to provide precise temperatures, masses, radii, and luminosities for the host stars. Combining our measurements of rotational broadening, rotation periods, and our derived stellar radii, we show that all planetary orbits are consistent with alignment to their host star’s rotation. We fit the K2 light curves, including priors on stellar density to put constraints on the planetary eccentricities, all of which are consistent with zero. The difference between the number of planets found in Praesepe and Hyades (8 planets, ≃ 800 Myr) and a similar data set for Pleiades (0 planets, ≃125 Myr) suggests a trend with age, but may be due to incompleteness of current search pipelines for younger, faster-rotating stars. We see increasing evidence that some planets continue to lose atmosphere past 800 Myr, as now two planets at this age have radii significantly larger than their older counterparts from Kepler.

  12. Science, art and geometrical imagination

    NASA Astrophysics Data System (ADS)

    Luminet, Jean-Pierre

    2011-06-01

    From the geocentric, closed world model of Antiquity to the wraparound universe models of relativistic cosmology, the parallel history of space representations in science and art illustrates the fundamental rôle of geometric imagination in innovative findings. Through the analysis of works of various artists and scientists like Plato, Dürer, Kepler, Escher, Grisey or the author, it is shown how the process of creation in science and in the arts rests on aesthetical principles such as symmetry, regular polyhedra, laws of harmonic proportion, tessellations, group theory, etc., as well as on beauty, conciseness and an emotional approach of the world.

  13. Anatomy of an Asteroid Breakup

    NASA Astrophysics Data System (ADS)

    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

  14. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bereau, Tristan, E-mail: bereau@mpip-mainz.mpg.de; Lilienfeld, O. Anatole von

    We estimate polarizabilities of atoms in molecules without electron density, using a Voronoi tesselation approach instead of conventional density partitioning schemes. The resulting atomic dispersion coefficients are calculated, as well as many-body dispersion effects on intermolecular potential energies. We also estimate contributions from multipole electrostatics and compare them to dispersion. We assess the performance of the resulting intermolecular interaction model from dispersion and electrostatics for more than 1300 neutral and charged, small organic molecular dimers. Applications to water clusters, the benzene crystal, the anti-cancer drug ellipticine—intercalated between two Watson-Crick DNA base pairs, as well as six macro-molecular host-guest complexes highlightmore » the potential of this method and help to identify points of future improvement. The mean absolute error made by the combination of static electrostatics with many-body dispersion reduces at larger distances, while it plateaus for two-body dispersion, in conflict with the common assumption that the simple 1/R{sup 6} correction will yield proper dissociative tails. Overall, the method achieves an accuracy well within conventional molecular force fields while exhibiting a simple parametrization protocol.« less

  15. The Evolution of the Surface of Symmetry of the Interplanetary Dust from 24° to 5° Elongation

    NASA Astrophysics Data System (ADS)

    Stenborg, Guillermo; Howard, Russell A.

    2017-10-01

    The white-light STEREO/SECCHI images include light scattered by dust in orbit about the Sun (the F-corona). We analyzed the evolution of the symmetry axis of the F-corona between 2007 and 2012 in the elongation range covered by the STEREO-A/HI-1 instrument (4°-24° elongation) to characterize the plane of symmetry of the zodiacal dust cloud. The symmetry axes both above and below the ecliptic plane were derived separately without assuming any particular functional form. No noticeable time dependence was observed. However, we did find an evolution with elongation of both the inclination I and the ascending node {{{Ω }}}A of the inferred plane of symmetry. Both parameters appeared fairly constant in the outer half of the elongation range studied (I=˜ 3\\buildrel{\\circ}\\over{.} 7,{{{Ω }}}A=˜ 83^\\circ ; values close to those of Venus’s orbit). Then, they start to evolve, becoming I=˜ 6^\\circ (I.e., a trend toward the solar equatorial plane) and {{{Ω }}}A=˜ 57^\\circ at about 5° elongation. This variation indicates that the zodiacal dust cloud exhibits a warped plane of symmetry, with an estimated center of symmetry at about 0.5 {R}⊙ from the Sun’s center on the side of the heliosphere containing Jupiter. We found a marginal difference between the inclination of the axes below and above the ecliptic. This is suggestive of an increased dust density distribution at certain fixed longitudes, which could be explained by the dust deposition of Kreutz Sun-grazing comets. We conjecture that the circumsolar dust is mainly affected by gravitational forces, other forces becoming dominant only where the more rapid changes occur.

  16. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, Christine H.; Mittal, Tushar; Kuchner, Marc

    During the Spitzer Space Telescope cryogenic mission, Guaranteed Time Observers, Legacy Teams, and General Observers obtained Infrared Spectrograph (IRS) observations of hundreds of debris disk candidates. We calibrated the spectra of 571 candidates, including 64 new IRAS and Multiband Imaging Photometer for Spitzer (MIPS) debris disks candidates, modeled their stellar photospheres, and produced a catalog of excess spectra for unresolved debris disks. For 499 targets with IRS excess but without strong spectral features (and a subset of 420 targets with additional MIPS 70 μm observations), we modeled the IRS (and MIPS data) assuming that the dust thermal emission was well-describedmore » using either a one- or two-temperature blackbody model. We calculated the probability for each model and computed the average probability to select among models. We found that the spectral energy distributions for the majority of objects (∼66%) were better described using a two-temperature model with warm (T {sub gr} ∼ 100-500 K) and cold (T {sub gr} ∼ 50-150 K) dust populations analogous to zodiacal and Kuiper Belt dust, suggesting that planetary systems are common in debris disks and zodiacal dust is common around host stars with ages up to ∼1 Gyr. We found that younger stars generally have disks with larger fractional infrared luminosities and higher grain temperatures and that higher-mass stars have disks with higher grain temperatures. We show that the increasing distance of dust around debris disks is inconsistent with self-stirred disk models, expected if these systems possess planets at 30-150 AU. Finally, we illustrate how observations of debris disks may be used to constrain the radial dependence of material in the minimum mass solar nebula.« less

  17. Modeling Resonant Structure in the Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Holmes, E. K.; Dermott, S. F.; Grogan, K.

    1999-12-01

    There is a possible connection between structure in circumstellar disks and the presence of planets, our own zodiacal cloud being the prime example. Asymmetries in such a disk could be diagnostic of planets which would be otherwise undetectable. At least three different types of asymmetries can serve to indicate bodies orbiting a star in a disk: (1) a warp in the plane of symmetry of the disk, (2) an offset in the center of symmetry of the disk with respect to the central star, and (3) density anomalies in the plane of the disk due to resonant trapping of dust particles. In the asteroid belt, collisions between asteroids supply dust particles to the zodiacal cloud. By comparison, it has been postulated that collisions between KBOs could initiate a collisional cascade which would produce a Kuiper dust disk. In fact, the Kuiper Belt is the region of our solar system that is most analogous to the planetary debris disks we see around other stars such as Vega, β Pic, Fomalhaut, and ɛ Eridani (Backman and Paresce 1993). A Kuiper Disk would most likely have a resonant structure, with two concentrations in brightness along the ecliptic longitude. This large scale structure arises because many of the KBOs, the Plutinos, are in the 2:3 mean motion resonance with Neptune. By running numerical integrations of particles in Pluto-like orbits, the resonant structure of the Kuiper belt can be studied by determining the percentage of particles trapped in the resonance as a function of their initial velocity and beta, where β = Frad}/F{grav. The dynamical evolution of the particles is followed from source to sink with Poynting Robertson light drag, solar wind drag, radiation pressure, and the effects of planetary gravitational perturbations included. This research was funded in part by a NASA GSRP grant.

  18. Modeling Resonant Structure in the Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Holmes, E. K.; Dermott, S. F.; Grogan, K.

    1999-09-01

    There is a possible connection between structure in circumstellar disks and the presence of planets, our own zodiacal cloud being the prime example. Asymmetries in such a disk could be diagnostic of planets which would be otherwise undetectable. At least three different types of asymmetries can serve to indicate bodies orbiting a star in a disk: (1) a warp in the plane of symmetry of the disk, (2) an offset in the center of symmetry of the disk with respect to the central star, and (3) density anomalies in the plane of the disk due to resonant trapping of dust particles. In the asteroid belt, collisions between asteroids supply dust particles to the zodiacal cloud. By comparison, it has been postulated that collisions between KBOs could initiate a collisional cascade which would produce a Kuiper dust disk. In fact, the Kuiper Belt is the region of our solar system that is most analogous to the planetary debris disks we see around other stars such as Vega, beta Pic, Fomalhaut, and epsilon Eridani (Backman and Paresce 1993). A Kuiper Disk would most likely have a resonant structure, with two concentrations in brightness along the ecliptic longitude. This large scale structure arises because many of the KBOs, the Plutinos, are in the 2:3 mean motion resonance with Neptune. By running numerical integrations of particles in Pluto-like orbits, the resonant structure of the Kuiper belt can be studied by determining the percentage of particles trapped in the resonance as a function of their initial velocity and beta, where beta = Frad/Fgrav. The dynamical evolution of the particles is followed from source to sink with Poynting Robertson light drag, solar wind drag, radiation pressure, and the effects of planetary gravitational perturbations included. This research was funded in part by a NASA GSRP grant.

  19. The nature of the near-infrared interline sky background using fibre Bragg grating OH suppression

    NASA Astrophysics Data System (ADS)

    Trinh, Christopher Q.; Ellis, Simon C.; Bland-Hawthorn, Joss; Horton, Anthony J.; Lawrence, Jon S.; Leon-Saval, Sergio G.

    2013-07-01

    We analyse the near-infrared interline sky background, OH and O2 emission in 19 h of H-band observations with the GNOSIS OH-suppression unit and the IRIS2 spectrograph at the 3.9-m Anglo-Australian Telescope. We find that the long-term behaviour of OH emission is best described by a gradual decrease during the first half of the night followed by a gradual increase during the second half of the night following the behaviour of the solar elevation angle. We measure the interline background at 1.520 μm where the instrumental thermal background is very low and study its variation with zenith distance, time after sunset, ecliptic latitude, lunar zenith distance and lunar distance to determine the presence of non-thermal atmospheric emission, zodiacal scattered light and scattered moonlight. Zodiacal scattered light is too faint to be detected in the summed observations. Scattered moonlight due to Mie scattering by atmospheric aerosols is seen at small lunar distances (ρ ≲ 11°), but is otherwise too faint to detect. Except at very small lunar distances the interline background at a resolving power of R ≈ 2400 when using OH-suppression fibres is dominated by a non-thermal atmospheric source with a temporal behaviour that resembles atmospheric OH emission, suggesting that the interline background contains instrumentally scattered OH. However, the interline background dims more rapidly than OH early in the night, suggesting contributions from rapid dimming molecules. The absolute interline background is 560 ± 120 photons s-1 m-2 μm- 1 arcsec-2 under dark conditions. This value is similar to previous measurements without OH suppression, suggesting that non-suppressed atmospheric emission is responsible for the interline background level. Future OH-suppression fibre designs may address this by the suppression of more sky lines using more accurate sky-line measurements taken from high-resolution spectra.

  20. The accuracy of the measurements in Ulugh Beg's star catalogue

    NASA Astrophysics Data System (ADS)

    Krisciunas, K.

    1992-12-01

    The star catalogue compiled by Ulugh Beg and his collaborators in Samarkand (ca. 1437) is the only catalogue primarily based on original observations between the times of Ptolemy and Tycho Brahe. Evans (1987) has given convincing evidence that Ulugh Beg's star catalogue was based on measurements made with a zodiacal armillary sphere graduated to 15(') , with interpolation to 0.2 units. He and Shevchenko (1990) were primarily interested in the systematic errors in ecliptic longitude. Shevchenko's analysis of the random errors was limited to the twelve zodiacal constellations. We have analyzed all 843 ecliptic longitudes and latitudes attributed to Ulugh Beg by Knobel (1917). This required multiplying all the longitude errors by the respective values of the cosine of the celestial latitudes. We find a random error of +/- 17minp 7 for ecliptic longitude and +/- 16minp 5 for ecliptic latitude. On the whole, the random errors are largest near the ecliptic, decreasing towards the ecliptic poles. For all of Ulugh Beg's measurements (excluding outliers) the mean systematic error is -10minp 8 +/- 0minp 8 for ecliptic longitude and 7minp 5 +/- 0minp 7 for ecliptic latitude, with the errors in the sense ``computed minus Ulugh Beg''. For the brighter stars (those designated alpha , beta , and gamma in the respective constellations), the mean systematic errors are -11minp 3 +/- 1minp 9 for ecliptic longitude and 9minp 4 +/- 1minp 5 for ecliptic latitude. Within the errors this matches the systematic error in both coordinates for alpha Vir. With greater confidence we may conclude that alpha Vir was the principal reference star in the catalogues of Ulugh Beg and Ptolemy. Evans, J. 1987, J. Hist. Astr. 18, 155. Knobel, E. B. 1917, Ulugh Beg's Catalogue of Stars, Washington, D. C.: Carnegie Institution. Shevchenko, M. 1990, J. Hist. Astr. 21, 187.

  1. KSC-2014-4766

    NASA Image and Video Library

    2014-12-05

    SAN DIEGO, Calif. -- NASA's Orion spacecraft splashed down in the Pacific Ocean after its first flight test atop a Delta IV Heavy rocket from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida. U.S. Navy divers in Zodiac boats prepare to recover Orion and tow her in to the well deck of the USS Anchorage. NASA's Orion spacecraft completed a two-orbit, four-and-a-half hour mission to test systems critical to crew safety, including the launch abort system, the heat shield and the parachute system. The Ground Systems Development and Operations Program is leading the recovery efforts. For more information, visit www.nasa.gov/orion Photo credit: Courtesy of U.S. Navy

  2. Solar radiation induced rotational bursting of interplanetary particles

    NASA Technical Reports Server (NTRS)

    Sparrow, J. G.

    1975-01-01

    It is suggested that the magnitudes of the two radiation-induced rotational bursting mechanisms (Radzieskii effect and windmill effect) have been overestimated and that they do not work significantly faster than the Poynting-Robertson effect in removing interplanetary particles. These two mechanisms are described, and serious doubts are raised regarding the derivation of their radiation pressure-torque proportionality constants, which are required for calculating their magnitudes. It is shown that both mechanisms will cause the alignment of elongated particles and, consequently, the polarization of zodiacal light. Since no positive polarization has been measured at the antisolar point, it is concluded that the magnitudes of the rotational bursting mechanisms are smaller than that of the Poynting-Robertson effect.

  3. Characteristics of CMEs observed in the heliosphere using Helios photometer data. [coronal mass ejection

    NASA Technical Reports Server (NTRS)

    Webb, D. F.; Jackson, B. V.

    1992-01-01

    The zodiacal light photometers on the two Helios spacecraft have been used to detect and study mass ejections and other phenomena emanating from the sun and traversing the heliosphere within 1 AU. We have recently compiled a complete list of all of the significant white light transient events detected from the 90-deg photometers on both Helios spacecraft. This is a preliminary report on the long-term frequency of occurrence of these events; it emphasizes newly processed data from Helios-l from 1975 through 1982 and viewed south of the ecliptic. With the large Helios photometer data base, we will be able to identify the fraction of the 90 deg events which are heliospheric CMEs and determine their characteristics.

  4. Part-set cueing impairment & facilitation in semantic memory.

    PubMed

    Kelley, Matthew R; Parihar, Sushmeena A

    2018-01-19

    The present study explored the influence of part-set cues in semantic memory using tests of "free" recall, reconstruction of order, and serial recall. Nine distinct categories of information were used (e.g., Zodiac signs, Harry Potter books, Star Wars films, planets). The results showed part-set cueing impairment for all three "free" recall sets, whereas part-set cueing facilitation was evident for five of the six ordered sets. Generally, the present results parallel those often observed across episodic tasks, which could indicate that similar mechanisms contribute to part-set cueing effects in both episodic and semantic memory. A novel anchoring explanation of part-set cueing facilitation in order and spatial tasks is provided.

  5. Contributions to the History of Astronomy, Vol. 3. (German Title: Beiträge zur Astronomiegeschichte, Band 3)

    NASA Astrophysics Data System (ADS)

    Dick, Wolfgang R.; Hamel, Jürgen

    The main papers of this issue deal with previously unknown details of the foundation of the astronomical observatories in Gotha and in Königsberg (with numerous original documents by F.W. Bessel), with the Mecklenburg ordnance survey (1853-1873, with previously unknown letters by C.F. Gauss), with the merits of the Leipzig astronomer G.A. Jahn, with the internationality of the Astronomische Gesellschaft, and with early, previously little noted works on the expansion of the Universe. The issue contains a description of the important collection of sundials in the Kassel museum, discussions about the Medieval ``Phantom Period'', about Goethe's description of the zodiacal light, as well as obituaries and book reviews. Most papers in German, one in English.

  6. An infrared sky model based on the IRAS point source data

    NASA Technical Reports Server (NTRS)

    Cohen, Martin; Walker, Russell; Wainscoat, Richard; Volk, Kevin; Walker, Helen; Schwartz, Deborah

    1990-01-01

    A detailed model for the infrared point source sky is presented that comprises geometrically and physically realistic representations of the galactic disk, bulge, spheroid, spiral arms, molecular ring, and absolute magnitudes. The model was guided by a parallel Monte Carlo simulation of the Galaxy. The content of the galactic source table constitutes an excellent match to the 12 micrometer luminosity function in the simulation, as well as the luminosity functions at V and K. Models are given for predicting the density of asteroids to be observed, and the diffuse background radiance of the Zodiacal cloud. The model can be used to predict the character of the point source sky expected for observations from future infrared space experiments.

  7. Towards a consistent framework to oversample multi-sensors, multi-species satellite data into a common grid

    NASA Astrophysics Data System (ADS)

    Sun, K.; Zhu, L.; Gonzalez Abad, G.; Nowlan, C. R.; Miller, C. E.; Huang, G.; Liu, X.; Chance, K.; Yang, K.

    2017-12-01

    It has been well demonstrated that regridding Level 2 products (satellite observations from individual footprints, or pixels) from multiple sensors/species onto regular spatial and temporal grids makes the data more accessible for scientific studies and can even lead to additional discoveries. However, synergizing multiple species retrieved from multiple satellite sensors faces many challenges, including differences in spatial coverage, viewing geometry, and data filtering criteria. These differences will lead to errors and biases if not treated carefully. Operational gridded products are often at 0.25°×0.25° resolution with a global scale, which is too coarse for local heterogeneous emission sources (e.g., urban areas), and at fixed temporal intervals (e.g., daily or monthly). We propose a consistent framework to fully use and properly weight the information of all possible individual satellite observations. A key aspect of this work is an accurate knowledge of the spatial response function (SRF) of the satellite Level 2 pixels. We found that the conventional overlap-area-weighting method (tessellation) is accurate only when the SRF is homogeneous within the parameterized pixel boundary and zero outside the boundary. There will be a tessellation error if the SRF is a smooth distribution, and if this distribution is not properly considered. On the other hand, discretizing the SRF at the destination grid will also induce errors. By balancing these error sources, we found that the SRF should be used in gridding OMI data to 0.2° for fine resolutions. Case studies by merging multiple species and wind data into 0.01° grid will be shown in the presentation.

  8. Large batoid fishes frequently consume stingrays despite skeletal damage

    PubMed Central

    Bizzarro, Joseph J.; Clark, Brett; Underwood, Charlie J.

    2017-01-01

    The shapes of vertebrate teeth are often used as hallmarks of diet. Here, however, we demonstrate evidence of frequent piscivory by cartilaginous fishes with pebble-like teeth that are typically associated with durophagy, the eating of hard-shelled prey. High-resolution micro-computed tomography observation of a jaw specimen from one batoid species and visual investigation of those of two additional species reveal large numbers of embedded stingray spines, arguing that stingray predation of a scale rivalling that of the largest carnivorous sharks may not be uncommon for large, predatory batoids with rounded, non-cutting dentition. Our observations demonstrate that tooth morphology is not always a reliable indicator of diet and that stingray spines are not as potent a deterrent to predation as normally believed. In addition, we show that several spines in close contact with the jaw skeleton of a wedgefish (Rhynchobatus) have become encased in a disorganized mineralized tissue with a distinctive ultrastructure, the first natural and unequivocal evidence of a callus-building response in the tessellated cartilage unique to elasmobranch skeletons. Our findings reveal sampling and analysis biases in vertebrate ecology, especially with regard to the role of large, predatory species, while also illustrating that large body size may provide an escape from anatomical constraints on diet (e.g. gape size, specialist dentition). Our observations inform our concepts of skeletal biology and evolution in showing that tessellated cartilage—an ancient alternative to bone—is incapable of foreign tissue resorption or of restoring damaged skeletal tissue to its original state, and attest to the value of museum and skeletal specimens as records of important aspects of animal life history. PMID:28989770

  9. Advanced Speckle Sensing for Internal Coronagraphs

    NASA Technical Reports Server (NTRS)

    Noecker, Charley; Shaklan, Stuart B.; Wallace, James K.; Kern, Brian D.; Give'on, Amir; Kasdin, Jeremy; Belikov, Ruslan; Kendrick, Steve

    2011-01-01

    A 4-8m telescope carrying a coronagraph instrument is a leading candidate for an anticipated flagship mission to detect and characterize Earth-size exoplanets in the 2020s. Many candidate coronagraph instruments have been proposed, and one has met many of the principal requirements for that mission. But the telescope and instrument will need exquisite stability and precise control of the incoming wavefront to enable detection of faint companions (10(exp -10) of the star) at an angular separation of 2-4 Airy radii. In particular, wavefront errors cause speckles in the image, and variations in those speckles can confound the exoplanet detection. This challenge is compounded by the background light from zodiacal dust around our Sun and the target star, which limits the speed with which we can estimate and correct the speckles. We are working on developing coherent speckle detection techniques that will allow rapid calibration of speckles on the science detector, allowing subtraction in post-processing or correction with deformable mirrors. The expected speed improvement allows a much quicker timeline for measurement & calibration, which reduces the required telescope stability requirement and eases both the flight system design and the challenge of ground testing. We will describe the experiments and summarize progress to date.

  10. Advanced speckle sensing for internal coronagraphs

    NASA Astrophysics Data System (ADS)

    Noecker, Charley; Shaklan, Stuart; Wallace, James K.; Kern, Brian; Give'on, Amir; Kasdin, Jeremy; Belikov, Ruslan; Kendrick, Steve

    2011-10-01

    A 4-8m diameter telescope carrying a coronagraph instrument is a leading candidate for an anticipated flagship mission to detect and characterize Earth-size exoplanets in the 2020s.1 Many candidate coronagraph instruments have been proposed, and one is close to meeting some of the principal requirements for that mission. But the telescope and instrument will need exquisite stability and precise control of the incoming wavefront to enable detection of faint companions (10-10of the star) at an angular separation of 2-4 Airy radii. In particular, wavefront errors cause speckles in the image, and variations in those speckles can confound the exoplanet detection. This challenge is compounded by the background light from zodiacal dust around our Sun and the target star, which limits the speed with which we can estimate and correct the speckles. We are working on developing coherent speckle detection techniques that will allow rapid calibration of speckles on the science detector, allowing subtraction in post-processing or correction with deformable mirrors. The expected speed improvement allows a much quicker timeline for measurement & calibration, which reduces the required telescope stability requirement and eases both the flight system design and the challenge of ground testing. We will describe the experiments and summarize progress to date.

  11. A novel quantitative methodology for age evaluation of the human corneal endothelium

    NASA Astrophysics Data System (ADS)

    Rannou, Klervi; Thuret, Gilles; Gain, Philippe; Pinoli, Jean-Charles; Gavet, Yann

    2017-03-01

    The human corneal endothelium regulates the cornea transparency. Its cells, that cannot regenerate after birth, form a tesselated mosaic with almost perfect hexagonal cells during childhood, becoming progressively bigger and less ordered during aging. This study included 50 patients (in 10 decades groups) and 10 specular microscopy observations per patient. Five different criteria were measured on the manually segmented cells: area and perimeter of the cells as well as reduced Minkowski functionals. All these criteria were used to assess the probability of age group membership. We demonstrated that the age evaluation is near the reality, although a high variability was observed for patients between 30 and 70 years old.

  12. CAD-Based Aerodynamic Design of Complex Configurations using a Cartesian Method

    NASA Technical Reports Server (NTRS)

    Nemec, Marian; Aftosmis, Michael J.; Pulliam, Thomas H.

    2003-01-01

    A modular framework for aerodynamic optimization of complex geometries is developed. By working directly with a parametric CAD system, complex-geometry models are modified nnd tessellated in an automatic fashion. The use of a component-based Cartesian method significantly reduces the demands on the CAD system, and also provides for robust and efficient flowfield analysis. The optimization is controlled using either a genetic or quasi-Newton algorithm. Parallel efficiency of the framework is maintained even when subject to limited CAD resources by dynamically re-allocating the processors of the flow solver. Overall, the resulting framework can explore designs incorporating large shape modifications and changes in topology.

  13. FacetModeller: Software for manual creation, manipulation and analysis of 3D surface-based models

    NASA Astrophysics Data System (ADS)

    Lelièvre, Peter G.; Carter-McAuslan, Angela E.; Dunham, Michael W.; Jones, Drew J.; Nalepa, Mariella; Squires, Chelsea L.; Tycholiz, Cassandra J.; Vallée, Marc A.; Farquharson, Colin G.

    2018-01-01

    The creation of 3D models is commonplace in many disciplines. Models are often built from a collection of tessellated surfaces. To apply numerical methods to such models it is often necessary to generate a mesh of space-filling elements that conforms to the model surfaces. While there are meshing algorithms that can do so, they place restrictive requirements on the surface-based models that are rarely met by existing 3D model building software. Hence, we have developed a Java application named FacetModeller, designed for efficient manual creation, modification and analysis of 3D surface-based models destined for use in numerical modelling.

  14. Create and Publish a Hierarchical Progressive Survey (HiPS)

    NASA Astrophysics Data System (ADS)

    Fernique, P.; Boch, T.; Pineau, F.; Oberto, A.

    2014-05-01

    Since 2009, the CDS promotes a method for visualizing based on the HEALPix sky tessellation. This method, called “Hierarchical Progressive Survey" or HiPS, allows one to display a survey progressively. It is particularly suited for all-sky surveys or deep fields. This visualization method is now integrated in several applications, notably Aladin, the SiTools/MIZAR CNES framework, and the recent HTML5 “Aladin Lite". Also, more than one hundred surveys are already available in this view mode. In this article, we will present the progress concerning this method and its recent adaptation to the astronomical catalogs such as the GAIA simulation.

  15. Efficient Voronoi volume estimation for DEM simulations of granular materials under confined conditions

    PubMed Central

    Frenning, Göran

    2015-01-01

    When the discrete element method (DEM) is used to simulate confined compression of granular materials, the need arises to estimate the void space surrounding each particle with Voronoi polyhedra. This entails recurring Voronoi tessellation with small changes in the geometry, resulting in a considerable computational overhead. To overcome this limitation, we propose a method with the following features:•A local determination of the polyhedron volume is used, which considerably simplifies implementation of the method.•A linear approximation of the polyhedron volume is utilised, with intermittent exact volume calculations when needed.•The method allows highly accurate volume estimates to be obtained at a considerably reduced computational cost. PMID:26150975

  16. Improving Patient Safety: Improving Communication.

    PubMed

    Bittner-Fagan, Heather; Davis, Joshua; Savoy, Margot

    2017-12-01

    Communication among physicians, staff, and patients is a critical element in patient safety. Effective communication skills can be taught and improved through training and awareness. The practice of family medicine allows for long-term relationships with patients, which affords opportunities for ongoing, high-quality communication. There are many barriers to effective communication, including patient factors, clinician factors, and system factors, but tools and strategies exist to address these barriers, improve communication, and engage patients in their care. Use of universal precautions for health literacy, appropriate medical interpreters, and shared decision-making are evidence-based tools that improve communication and increase patient safety. Written permission from the American Academy of Family Physicians is required for reproduction of this material in whole or in part in any form or medium.

  17. Improving Earth/Prediction Models to Improve Network Processing

    NASA Astrophysics Data System (ADS)

    Wagner, G. S.

    2017-12-01

    The United States Atomic Energy Detection System (USAEDS) primaryseismic network consists of a relatively small number of arrays andthree-component stations. The relatively small number of stationsin the USAEDS primary network make it both necessary and feasibleto optimize both station and network processing.Station processing improvements include detector tuning effortsthat use Receiver Operator Characteristic (ROC) curves to helpjudiciously set acceptable Type 1 (false) vs. Type 2 (miss) errorrates. Other station processing improvements include the use ofempirical/historical observations and continuous background noisemeasurements to compute time-varying, maximum likelihood probabilityof detection thresholds.The USAEDS network processing software makes extensive use of theazimuth and slowness information provided by frequency-wavenumberanalysis at array sites, and polarization analysis at three-componentsites. Most of the improvements in USAEDS network processing aredue to improvements in the models used to predict azimuth, slowness,and probability of detection. Kriged travel-time, azimuth andslowness corrections-and associated uncertainties-are computedusing a ground truth database. Improvements in station processingand the use of improved models for azimuth, slowness, and probabilityof detection have led to significant improvements in USADES networkprocessing.

  18. Improvements to rural intersections to improve motorist compliance.

    DOT National Transportation Integrated Search

    2014-10-01

    The Texas Department of Transportation (TxDOT) has placed improving safety as one of its top objectives. : Improving safety in rural intersections is a means to improve roadway safety especially in rural districts such : as the districts in West Texa...

  19. PconsFold: improved contact predictions improve protein models.

    PubMed

    Michel, Mirco; Hayat, Sikander; Skwark, Marcin J; Sander, Chris; Marks, Debora S; Elofsson, Arne

    2014-09-01

    Recently it has been shown that the quality of protein contact prediction from evolutionary information can be improved significantly if direct and indirect information is separated. Given sufficiently large protein families, the contact predictions contain sufficient information to predict the structure of many protein families. However, since the first studies contact prediction methods have improved. Here, we ask how much the final models are improved if improved contact predictions are used. In a small benchmark of 15 proteins, we show that the TM-scores of top-ranked models are improved by on average 33% using PconsFold compared with the original version of EVfold. In a larger benchmark, we find that the quality is improved with 15-30% when using PconsC in comparison with earlier contact prediction methods. Further, using Rosetta instead of CNS does not significantly improve global model accuracy, but the chemistry of models generated with Rosetta is improved. PconsFold is a fully automated pipeline for ab initio protein structure prediction based on evolutionary information. PconsFold is based on PconsC contact prediction and uses the Rosetta folding protocol. Due to its modularity, the contact prediction tool can be easily exchanged. The source code of PconsFold is available on GitHub at https://www.github.com/ElofssonLab/pcons-fold under the MIT license. PconsC is available from http://c.pcons.net/. Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press.

  20. "Rheum to Improve": Quality Improvement in Outpatient Rheumatology.

    PubMed

    Chow, Shirley L; Shojania, Kaveh G

    2017-09-01

    The commitment to improve care processes and patient outcomes is a professional mandate for clinicians and is also seen as an operational priority for institutions. Quality improvement now figures in the accreditation of training programs, specialty examinations, and hospital scorecards. Rheumatologists have traditionally focused primarily on quality problems such as guideline adherence; however, improvement goals should also include other aspects of care that are helpful to patients and are professionally rewarding for practitioners. This review makes use of improvement projects in outlining tangible tools rheumatologists can use to resolve quality concerns in their practices.

  1. Multiplexing in astrophysics with a UV multi-object spectrometer on CETUS, a probe-class mission study

    NASA Astrophysics Data System (ADS)

    Kendrick, Stephen E.; Woodruff, Robert A.; Hull, Tony; Heap, Sara R.; Kutyrev, Alexander; Danchi, William; Purves, Lloyd

    2017-09-01

    The ultraviolet multi-object spectrograph (MOS) for the Cosmic Evolution Through UV Spectroscopy (CETUS) concept1,2 is a slit-based instrument allowing multiple simultaneous observations over a wide field of view. It utilizes a next-generation micro-shutter array, an efficient aspheric Offner spectrometer design with a convex grating, and carbon nanotube light traps for suppressing unwanted wavelengths. The optical coatings are also designed to optimize the UV throughput while minimizing out-of-band signal at the detector. The UV MOS will be able to target up to 100 objects at a time without the issues of confusion with nearby sources or unwanted background like zodiacal stray light. With this multiplexing, the scientific yield of both Probe and Great Observatories will be greatly enhanced.

  2. Long Baseline Nulling Interferometry with the Keck Telescopes: A Progress Report

    NASA Technical Reports Server (NTRS)

    Mennesson, Bertrand; Akeson, R.; Appleby, E.; Bell, J.; Booth, A.; Colavita, M. M.; Crawford, S.; Creech-Eakman, M. J.; Dahl, W.; Fanson, J.; hide

    2005-01-01

    The Keck Interferometer Nuller (KIN) is one of the major scientific and technical precursors to the Terrestrial Planet Finder Interferometer (TPF-I) mission. KIN's primary objective is to measure the level of exo-zodiacal mid-infrared emission around nearby main sequence stars, which requires deep broad-band nulling of astronomical sources of a few Janskys at 10 microns. A number of new capabilities are needed in order to reach that goal with the Keck telescopes: mid-infrared coherent recombination, interferometric operation in 'split pupil' mode, N-band optical path stabilization using K-band fringe tracking and internal metrology, and eventually, active atmospheric dispersion correction. We report here on the progress made implementing these new functionalities, and discuss the initial levels of extinction achieved on the sky.

  3. Unraveling the Mystery of Exozodiacal Dust

    NASA Astrophysics Data System (ADS)

    Ertel, S.; Augereau, J.-C.; Thébault, P.; Absil, O.; Bonsor, A.; Defrère, D.; Kral, Q.; Le Bouquin, J.-B.; Lebreton, J.; Coudé du Foresto, V.

    2014-01-01

    Exozodiacal dust clouds are thought to be the extrasolar analogs of the Solar System's zodiacal dust. Studying these systems provides insights in the architecture of the innermost regions of planetary systems, including the Habitable Zone. Furthermore, the mere presence of the dust may result in major obstacles for direct imaging of earth-like planets. Our EXOZODI project aims to detect and study exozodiacal dust and to explain its origin. We are carrying out the first large, near-infrared interferometric survey in the northern (CHARA/FLUOR) and southern (VLTI/PIONIER) hemispheres. Preliminary results suggest a detection rate of up to 30% around A to K type stars and interesting trends with spectral type and age. We focus here on presenting the observational work carried out by our team.

  4. Multiwavelength micromirrors in the cuticle of scarab beetle Chrysina gloriosa.

    PubMed

    Agez, Gonzague; Bayon, Chloé; Mitov, Michel

    2017-01-15

    Beetles from the genus Chrysina show vivid reflections from bright green to metallic silver-gold as a consequence of the cholesteric liquid crystal organization of chitin molecules. Particularly, the cuticle of Chrysina gloriosa exhibits green and silver stripes. By combining confocal microscopy and spectrophotometry, scanning electron microscopy and numerical simulations, the relationship between the reflectance and the structural parameters for both stripes at the micro- and nanoscales are established. Over the visible and near IR spectra, polygonal cells in tessellated green stripes behave as multiwavelength selective micro-mirrors and the silver stripes as specular broadband mirrors. Thermoregulation, conspecifics or intra-species communication, or camouflage against predators are discussed as possible functions. As a prerequisite to bio-inspired artificial replicas, the physical characteristics of the polygonal texture in Chrysina gloriosa cuticle are compared to their equivalents in synthetic cholesteric oligomers and their fundamental differences are ascertained. It is shown that the cuticle has concave cells whereas the artificial films have convex cells, contrary to expectation and assumption in the literature. The present results may provide inspiration for fabricating multiwavelength selective micromirrors or spatial wavelength-specific light modulators. Many insects own a tessellated carapace with bumps, pits or indentations. Little is known on the physical properties of these geometric variations and biological functions are unknown or still debated. We show that the polygonal cells in scarab beetle Chrysina gloriosa behave as multiwavelength selective micromirrors over the visible and infrared spectra, with a variety of spatial patterns. In the context of biomimetic materials, we demonstrate that the carapace has concave cells whereas the artificial films have convex cells, contrary to expectation in the literature. Thermoregulation, communication or

  5. Influence of thread shape and inclination on the biomechanical behaviour of plateau implant systems.

    PubMed

    Calì, Michele; Zanetti, Elisabetta Maria; Oliveri, Salvatore Massimo; Asero, Riccardo; Ciaramella, Stefano; Martorelli, Massimo; Bignardi, Cristina

    2018-03-01

    To assess the influence of implant thread shape and inclination on the mechanical behaviour of bone-implant systems. The study assesses which factors influence the initial and full osseointegration stages. Point clouds of the original implant were created using a non-contact reverse engineering technique. A 3D tessellated surface was created using Geomagic Studio ® software. From cross-section curves, generated by intersecting the tessellated model and cutting-planes, a 3D parametric CAD model was created using SolidWorks ® 2017. By the permutation of three thread shapes (rectangular, 30° trapezoidal, 45° trapezoidal) and three thread inclinations (0°, 3° or 6°), nine geometric configurations were obtained. Two different osseointegration stages were analysed: the initial osseointegration and a full osseointegration. In total, 18 different FE models were analysed and two load conditions were applied to each model. The mechanical behaviour of the models was analysed by Finite Element (FE) Analysis using ANSYS ® v. 17.0. Static linear analyses were also carried out. ANOVA was used to assess the influence of each factor. Models with a rectangular thread and 6° inclination provided the best results and reduced displacement in the initial osseointegration stages up to 4.58%. This configuration also reduced equivalent VM stress peaks up to 54%. The same effect was confirmed for the full osseointegration stage, where 6° inclination reduced stress peaks by up to 62%. The FE analysis confirmed the beneficial effect of thread inclination, reducing the displacement in immediate post-operative conditions and equivalent VM stress peaks. Thread shape does not significantly influence the mechanical behaviour of bone-implant systems but contributes to reducing stress peaks in the trabecular bone in both the initial and full osseointegration stages. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  6. Mass calibration of galaxy clusters at redshift 0.1–1.0 using weak lensing in the Sloan Digital Sky Survey Stripe 82 co-add

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wiesner, Matthew P.; Lin, Huan; Soares-Santos, Marcelle

    We present galaxy cluster mass–richness relations found in the Sloan Digital Sky Survey Stripe 82 co-add using clusters found using a Voronoi tessellation cluster finder. These relations were found using stacked weak lensing shear observed in a large sample of galaxy clusters. These mass–richness relations are presented for four redshift bins, 0.1 < z ≤ 0.4, 0.4 < z ≤ 0.7, 0.7 < z ≤ 1.0 and 0.1 < z ≤ 1.0. We describe the sample of galaxy clusters and explain how these clusters were found using a Voronoi tessellation cluster finder. We fit a Navarro-Frenk-White profile to the stackedmore » weak lensing shear signal in redshift and richness bins in order to measure virial mass (M 200). We describe several effects that can bias weak lensing measurements, including photometric redshift bias, the effect of the central BCG, halo miscentering, photometric redshift uncertainty and foreground galaxy contamination. We present mass–richness relations using richness measure N VT with each of these effects considered separately as well as considered altogether. We also examine redshift evolution of the mass–richness relation. As a result, we present measurements of the mass coefficient (M 200|20) and the power-law slope (α) for power-law fits to the mass and richness values in each of the redshift bins. We find values of the mass coefficient of 8.49 ± 0.526, 14.1 ± 1.78, 30.2 ± 8.74 and 9.23 ± 0.525 × 10 13 h –1 M ⊙ for each of the four redshift bins, respectively. As a result, we find values of the power-law slope of 0.905 ± 0.0585, 0.948 ± 0.100, 1.33 ± 0.260 and 0.883 ± 0.0500, respectively.« less

  7. Mass calibration of galaxy clusters at redshift 0.1–1.0 using weak lensing in the Sloan Digital Sky Survey Stripe 82 co-add

    DOE PAGES

    Wiesner, Matthew P.; Lin, Huan; Soares-Santos, Marcelle

    2015-07-08

    We present galaxy cluster mass–richness relations found in the Sloan Digital Sky Survey Stripe 82 co-add using clusters found using a Voronoi tessellation cluster finder. These relations were found using stacked weak lensing shear observed in a large sample of galaxy clusters. These mass–richness relations are presented for four redshift bins, 0.1 < z ≤ 0.4, 0.4 < z ≤ 0.7, 0.7 < z ≤ 1.0 and 0.1 < z ≤ 1.0. We describe the sample of galaxy clusters and explain how these clusters were found using a Voronoi tessellation cluster finder. We fit a Navarro-Frenk-White profile to the stackedmore » weak lensing shear signal in redshift and richness bins in order to measure virial mass (M 200). We describe several effects that can bias weak lensing measurements, including photometric redshift bias, the effect of the central BCG, halo miscentering, photometric redshift uncertainty and foreground galaxy contamination. We present mass–richness relations using richness measure N VT with each of these effects considered separately as well as considered altogether. We also examine redshift evolution of the mass–richness relation. As a result, we present measurements of the mass coefficient (M 200|20) and the power-law slope (α) for power-law fits to the mass and richness values in each of the redshift bins. We find values of the mass coefficient of 8.49 ± 0.526, 14.1 ± 1.78, 30.2 ± 8.74 and 9.23 ± 0.525 × 10 13 h –1 M ⊙ for each of the four redshift bins, respectively. As a result, we find values of the power-law slope of 0.905 ± 0.0585, 0.948 ± 0.100, 1.33 ± 0.260 and 0.883 ± 0.0500, respectively.« less

  8. Graphical Methods for Quantifying Macromolecules through Bright Field Imaging

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chang, Hang; DeFilippis, Rosa Anna; Tlsty, Thea D.

    Bright ?eld imaging of biological samples stained with antibodies and/or special stains provides a rapid protocol for visualizing various macromolecules. However, this method of sample staining and imaging is rarely employed for direct quantitative analysis due to variations in sample fixations, ambiguities introduced by color composition, and the limited dynamic range of imaging instruments. We demonstrate that, through the decomposition of color signals, staining can be scored on a cell-by-cell basis. We have applied our method to Flbroblasts grown from histologically normal breast tissue biopsies obtained from two distinct populations. Initially, nuclear regions are segmented through conversion of color imagesmore » into gray scale, and detection of dark elliptic features. Subsequently, the strength of staining is quanti?ed by a color decomposition model that is optimized by a graph cut algorithm. In rare cases where nuclear signal is significantly altered as a result of samplepreparation, nuclear segmentation can be validated and corrected. Finally, segmented stained patterns are associated with each nuclear region following region-based tessellation. Compared to classical non-negative matrix factorization, proposed method (i) improves color decomposition, (ii) has a better noise immunity, (iii) is more invariant to initial conditions, and (iv) has a superior computing performance« less

  9. Exploring Spatio-temporal Dynamics of Cellular Automata for Pattern Recognition in Networks.

    PubMed

    Miranda, Gisele Helena Barboni; Machicao, Jeaneth; Bruno, Odemir Martinez

    2016-11-22

    Network science is an interdisciplinary field which provides an integrative approach for the study of complex systems. In recent years, network modeling has been used for the study of emergent phenomena in many real-world applications. Pattern recognition in networks has been drawing attention to the importance of network characterization, which may lead to understanding the topological properties that are related to the network model. In this paper, the Life-Like Network Automata (LLNA) method is introduced, which was designed for pattern recognition in networks. LLNA uses the network topology as a tessellation of Cellular Automata (CA), whose dynamics produces a spatio-temporal pattern used to extract the feature vector for network characterization. The method was evaluated using synthetic and real-world networks. In the latter, three pattern recognition applications were used: (i) identifying organisms from distinct domains of life through their metabolic networks, (ii) identifying online social networks and (iii) classifying stomata distribution patterns varying according to different lighting conditions. LLNA was compared to structural measurements and surpasses them in real-world applications, achieving improvement in the classification rate as high as 23%, 4% and 7% respectively. Therefore, the proposed method is a good choice for pattern recognition applications using networks and demonstrates potential for general applicability.

  10. Exploring Spatio-temporal Dynamics of Cellular Automata for Pattern Recognition in Networks

    PubMed Central

    Miranda, Gisele Helena Barboni; Machicao, Jeaneth; Bruno, Odemir Martinez

    2016-01-01

    Network science is an interdisciplinary field which provides an integrative approach for the study of complex systems. In recent years, network modeling has been used for the study of emergent phenomena in many real-world applications. Pattern recognition in networks has been drawing attention to the importance of network characterization, which may lead to understanding the topological properties that are related to the network model. In this paper, the Life-Like Network Automata (LLNA) method is introduced, which was designed for pattern recognition in networks. LLNA uses the network topology as a tessellation of Cellular Automata (CA), whose dynamics produces a spatio-temporal pattern used to extract the feature vector for network characterization. The method was evaluated using synthetic and real-world networks. In the latter, three pattern recognition applications were used: (i) identifying organisms from distinct domains of life through their metabolic networks, (ii) identifying online social networks and (iii) classifying stomata distribution patterns varying according to different lighting conditions. LLNA was compared to structural measurements and surpasses them in real-world applications, achieving improvement in the classification rate as high as 23%, 4% and 7% respectively. Therefore, the proposed method is a good choice for pattern recognition applications using networks and demonstrates potential for general applicability. PMID:27874024

  11. Exploring Spatio-temporal Dynamics of Cellular Automata for Pattern Recognition in Networks

    NASA Astrophysics Data System (ADS)

    Miranda, Gisele Helena Barboni; Machicao, Jeaneth; Bruno, Odemir Martinez

    2016-11-01

    Network science is an interdisciplinary field which provides an integrative approach for the study of complex systems. In recent years, network modeling has been used for the study of emergent phenomena in many real-world applications. Pattern recognition in networks has been drawing attention to the importance of network characterization, which may lead to understanding the topological properties that are related to the network model. In this paper, the Life-Like Network Automata (LLNA) method is introduced, which was designed for pattern recognition in networks. LLNA uses the network topology as a tessellation of Cellular Automata (CA), whose dynamics produces a spatio-temporal pattern used to extract the feature vector for network characterization. The method was evaluated using synthetic and real-world networks. In the latter, three pattern recognition applications were used: (i) identifying organisms from distinct domains of life through their metabolic networks, (ii) identifying online social networks and (iii) classifying stomata distribution patterns varying according to different lighting conditions. LLNA was compared to structural measurements and surpasses them in real-world applications, achieving improvement in the classification rate as high as 23%, 4% and 7% respectively. Therefore, the proposed method is a good choice for pattern recognition applications using networks and demonstrates potential for general applicability.

  12. Regional co-location pattern scoping on a street network considering distance decay effects of spatial interaction

    PubMed Central

    Yu, Wenhao

    2017-01-01

    Regional co-location scoping intends to identify local regions where spatial features of interest are frequently located together. Most of the previous researches in this domain are conducted on a global scale and they assume that spatial objects are embedded in a 2-D space, but the movement in urban space is actually constrained by the street network. In this paper we refine the scope of co-location patterns to 1-D paths consisting of nodes and segments. Furthermore, since the relations between spatial events are usually inversely proportional to their separation distance, the proposed method introduces the “Distance Decay Effects” to improve the result. Specifically, our approach first subdivides the street edges into continuous small linear segments. Then a value representing the local distribution intensity of events is estimated for each linear segment using the distance-decay function. Each kind of geographic feature can lead to a tessellated network with density attribute, and the generated multiple networks for the pattern of interest will be finally combined into a composite network by calculating the co-location prevalence measure values, which are based on the density variation between different features. Our experiments verify that the proposed approach is effective in urban analysis. PMID:28763496

  13. BaTMAn: Bayesian Technique for Multi-image Analysis

    NASA Astrophysics Data System (ADS)

    Casado, J.; Ascasibar, Y.; García-Benito, R.; Guidi, G.; Choudhury, O. S.; Bellocchi, E.; Sánchez, S. F.; Díaz, A. I.

    2016-12-01

    Bayesian Technique for Multi-image Analysis (BaTMAn) characterizes any astronomical dataset containing spatial information and performs a tessellation based on the measurements and errors provided as input. The algorithm iteratively merges spatial elements as long as they are statistically consistent with carrying the same information (i.e. identical signal within the errors). The output segmentations successfully adapt to the underlying spatial structure, regardless of its morphology and/or the statistical properties of the noise. BaTMAn identifies (and keeps) all the statistically-significant information contained in the input multi-image (e.g. an IFS datacube). The main aim of the algorithm is to characterize spatially-resolved data prior to their analysis.

  14. Profiles of electrified drops and bubbles

    NASA Technical Reports Server (NTRS)

    Basaran, O. A.; Scriven, L. E.

    1982-01-01

    Axisymmetric equilibrium shapes of conducting drops and bubbles, (1) pendant or sessile on one face of a circular parallel-plate capacitor or (2) free and surface-charged, are found by solving simultaneously the free boundary problem consisting of the augmented Young-Laplace equation for surface shape and the Laplace equation for electrostatic field, given the surface potential. The problem is nonlinear and the method is a finite element algorithm employing Newton iteration, a modified frontal solver, and triangular as well as quadrilateral tessellations of the domain exterior to the drop in order to facilitate refined analysis of sharply curved drop tips seen in experiments. The stability limit predicted by this computer-aided theoretical analysis agrees well with experiments.

  15. A mobile robot system for ground servicing operations on the space shuttle

    NASA Astrophysics Data System (ADS)

    Dowling, K.; Bennett, R.; Blackwell, M.; Graham, T.; Gatrall, S.; O'Toole, R.; Schempf, H.

    1992-11-01

    A mobile system for space shuttle servicing, the Tessellator, has been configured, designed and is currently being built and integrated. Robot tasks include chemical injection and inspection of the shuttle's thermal protection system. This paper outlines tasks, rationale, and facility requirements for the development of this system. A detailed look at the mobile system and manipulator follow with a look at mechanics, electronics, and software. Salient features of the mobile robot include omnidirectionality, high reach, high stiffness and accuracy with safety and self-reliance integral to all aspects of the design. The robot system is shown to meet task, facility, and NASA requirements in its design resulting in unprecedented specifications for a mobile-manipulation system.

  16. A mobile robot system for ground servicing operations on the space shuttle

    NASA Technical Reports Server (NTRS)

    Dowling, K.; Bennett, R.; Blackwell, M.; Graham, T.; Gatrall, S.; O'Toole, R.; Schempf, H.

    1992-01-01

    A mobile system for space shuttle servicing, the Tessellator, has been configured, designed and is currently being built and integrated. Robot tasks include chemical injection and inspection of the shuttle's thermal protection system. This paper outlines tasks, rationale, and facility requirements for the development of this system. A detailed look at the mobile system and manipulator follow with a look at mechanics, electronics, and software. Salient features of the mobile robot include omnidirectionality, high reach, high stiffness and accuracy with safety and self-reliance integral to all aspects of the design. The robot system is shown to meet task, facility, and NASA requirements in its design resulting in unprecedented specifications for a mobile-manipulation system.

  17. Kinetic and dynamic Delaunay tetrahedralizations in three dimensions

    NASA Astrophysics Data System (ADS)

    Schaller, Gernot; Meyer-Hermann, Michael

    2004-09-01

    We describe algorithms to implement fully dynamic and kinetic three-dimensional unconstrained Delaunay triangulations, where the time evolution of the triangulation is not only governed by moving vertices but also by a changing number of vertices. We use three-dimensional simplex flip algorithms, a stochastic visibility walk algorithm for point location and in addition, we propose a new simple method of deleting vertices from an existing three-dimensional Delaunay triangulation while maintaining the Delaunay property. As an example, we analyse the performance in various cases of practical relevance. The dual Dirichlet tessellation can be used to solve differential equations on an irregular grid, to define partitions in cell tissue simulations, for collision detection etc.

  18. Crystallization in a model glass: Influence of the boundary conditions

    NASA Astrophysics Data System (ADS)

    Jund, P.; Jullien, R.

    1998-06-01

    Using molecular dynamics calculations and the Voronoï tessellation, we study the evolution of the local structure of a soft-sphere glass vs. temperature starting from the liquid phase at different quenching rates. This study is done for different sizes and for two different boundary conditions, namely the usual cubic periodic boundary conditions and the isotropic hyperspherical boundary conditions for which the particles evolve on the surface of a hypersphere in four dimensions. Our results show that for small system sizes, crystallization can indeed be induced by the cubic boundary conditions. On the other hand, we show that finite-size effects are more pronounced on the hypersphere and that crystallization is artificially inhibited even for large system sizes.

  19. Molecular dynamics simulation of liquid structure for undercooled Zr-Nb alloys assisted with electrostatic levitation experiments

    NASA Astrophysics Data System (ADS)

    Yang, S. J.; Hu, L.; Wang, L.; Wei, B.

    2018-06-01

    The liquid structures of undercooled Zr90Nb10, Zr70Nb30 and Zr50Nb50 alloys were studied by molecular dynamics simulation combined with electrostatic levitation experiments. The densities of three alloys were measured by electrostatic levitation to modify the Zr-Nb potential functions by adjusting parameters in potential functions. In simulation, the atomic packing in Zr-Nb alloys was more ordered at lower temperatures. The Voronoi tessellation analyses indicated Nb-centered clusters were easier to form than Zr-centered clusters although the Nb content was less than 50%. The partial pair distribution functions showed that the interactions among Zr atoms are quite different to that among Nb atoms.

  20. Experimental and ab initio molecular dynamics simulation studies of liquid Al60Cu40 alloy

    NASA Astrophysics Data System (ADS)

    Wang, S. Y.; Kramer, M. J.; Xu, M.; Wu, S.; Hao, S. G.; Sordelet, D. J.; Ho, K. M.; Wang, C. Z.

    2009-04-01

    X-ray diffraction and ab initio molecular dynamics simulation studies of molten Al60Cu40 have been carried out between 973 and 1323 K. The structures obtained from our simulated atomic models are fully consistent with the experimental results. The local structures of the models analyzed using Honeycutt-Andersen and Voronoi tessellation methods clearly demonstrate that as the temperatures of the liquid is lowered it becomes more ordered. While no one cluster-type dominates the local structure of this liquid, the most prevalent polyhedra in the liquid structure can be described as distorted icosahedra. No obvious correlations between the clusters observed in the liquid and known stable crystalline phases in this system were observed.

  1. Distributed mean curvature on a discrete manifold for Regge calculus

    NASA Astrophysics Data System (ADS)

    Conboye, Rory; Miller, Warner A.; Ray, Shannon

    2015-09-01

    The integrated mean curvature of a simplicial manifold is well understood in both Regge Calculus and Discrete Differential Geometry. However, a well motivated pointwise definition of curvature requires a careful choice of the volume over which to uniformly distribute the local integrated curvature. We show that hybrid cells formed using both the simplicial lattice and its circumcentric dual emerge as a remarkably natural structure for the distribution of this local integrated curvature. These hybrid cells form a complete tessellation of the simplicial manifold, contain a geometric orthonormal basis, and are also shown to give a pointwise mean curvature with a natural interpretation as the fractional rate of change of the normal vector.

  2. Improving employee productivity through improved health.

    PubMed

    Mitchell, Rebecca J; Ozminkowski, Ronald J; Serxner, Seth

    2013-10-01

    The objective of this study was to estimate productivity-related savings associated with employee participation in health promotion programs. Propensity score weighting and multiple regression techniques were used to estimate savings. These techniques were adjusted for demographic and health status differences between participants who engaged in one or more telephonic health management programs and nonparticipants who were eligible for but did not engage in these programs. Employees who participated in a program and successfully improved their health care or lifestyle showed significant improvements in lost work time. These employees saved an average of $353 per person per year. This reflects about 10.3 hours in additional productive time annually, compared with similar, but nonparticipating employees. Participating in health promotion programs can help improve productivity levels among employees and save money for their employers.

  3. Reprocessing WFC3/IR Exposures Affected by Time-Variable Backgrounds

    NASA Astrophysics Data System (ADS)

    Brammer, G.

    2016-11-01

    The background seen in WFC3/IR observations frequently shows strong time-dependent behavior above the constant flux expected for zodiacal continuum light. This is often caused by an emission line of helium at 1.083 μm excited in the sun-illuminated upper atmosphere, when seen in the filters (F105W, F110W) and grisms (G102, G141) sensitive to the feature. The default behavior of the calwf3 pipeline assumes constant source-plus-background fluxes when it performs up-the-ramp fitting to identify cosmic rays and determine the average count rate within a MULTIACCUM IR exposure. calwf3 provides undesirable results in the presence of strongly variable backgrounds, primarily in the form of elevated and non-Gaussian noise in the FLT products. Here we describe methods to improve the noise properties of the reduced products. In the first, we simply turn off the calwf3 crcorr step, treating the IR detector as if it were a CCD, i.e., accumulating flux and reading it out at the end of the exposure. Next, we artificially flatten the ramps in the IMA products and then allow calwf3 to proceed as normal fitting the ramp and identifying CRs. Either of these procedures enable recovery of datasets otherwise corrupted beyond repair and have no discernible effects on photometry of sources in deep combined images.

  4. Moon phases and moon signs do not influence morbidity, mortality and long-term survival, after living donor kidney transplantation.

    PubMed

    Kleespies, A; Mikhailov, M; Khalil, P N; Pratschke, S; Khandoga, A; Stangl, M; Illner, W D; Angele, M K; Jauch, K W; Guba, M; Werner, J; Rentsch, M

    2017-09-04

    Approximately 11% of the German population are convinced that certain moon phases and moon signs may impact their health and the onset and clinical course of diseases. Before elective surgery, a considerable number of patients look to optimize the timing of the procedure based on the lunar cycle. Especially patients awaiting living donor kidney transplantation (LDKT) commonly look for an adjustment of the date of transplantation according to the moon calendar. This study therefore investigated the perioperative and long-term outcome of LDKT dependent on moon phases and zodiac signs. Patient data were prospectively collected in a continuously updated kidney transplant database. Two hundred and seventy-eight consecutive patients who underwent LDKT between 1994 and December 2009 were selected for the study and retrospectively assigned to the four moon phases (new-moon, waxing-moon, full-moon, and waning-moon) and the corresponding zodiac sign (moon sign Libra), based on the date of transplantation. Preexisting comorbidities, perioperative mortality, surgical outcome, and long-term survival data were analyzed. Of all LDKT procedures, 11.9, 39.9, 11.5, and 36.5% were performed during the new, waxing, full, and waning moon, respectively, and 6.2% during the moon sign Libra, which is believed to interfere with renal surgery. Survival rates at 1, 5, and 10 years after transplantation were 98.9, 92, and 88.7% (patient survival) and 97.4, 91.6, and 80.6% (graft survival) without any differences between all groups of lunar phases and moon signs. Overall perioperative complications and early graft loss occurred in 21.2 and 1.4%, without statistical difference (p > 0.05) between groups. Moon phases and the moon sign Libra had no impact on early and long-term outcome measures following LDKT in our study. Thus, concerns of patients awaiting LDKT regarding the ideal time of surgery can be allayed, and surgery may be scheduled independently of the lunar phases.

  5. A retrospective analysis of RET translocation, gene copy number gain and expression in NSCLC patients treated with vandetanib in four randomized Phase III studies.

    PubMed

    Platt, Adam; Morten, John; Ji, Qunsheng; Elvin, Paul; Womack, Chris; Su, Xinying; Donald, Emma; Gray, Neil; Read, Jessica; Bigley, Graham; Blockley, Laura; Cresswell, Carl; Dale, Angela; Davies, Amanda; Zhang, Tianwei; Fan, Shuqiong; Fu, Haihua; Gladwin, Amanda; Harrod, Grace; Stevens, James; Williams, Victoria; Ye, Qingqing; Zheng, Li; de Boer, Richard; Herbst, Roy S; Lee, Jin-Soo; Vasselli, James

    2015-03-23

    To determine the prevalence of RET rearrangement genes, RET copy number gains and expression in tumor samples from four Phase III non-small-cell lung cancer (NSCLC) trials of vandetanib, a selective inhibitor of VEGFR, RET and EGFR signaling, and to determine any association with outcome to vandetanib treatment. Archival tumor samples from the ZODIAC ( NCT00312377 , vandetanib ± docetaxel), ZEAL ( NCT00418886 , vandetanib ± pemetrexed), ZEPHYR ( NCT00404924 , vandetanib vs placebo) and ZEST ( NCT00364351 , vandetanib vs erlotinib) studies were evaluated by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) in 944 and 1102 patients. The prevalence of RET rearrangements by FISH was 0.7% (95% CI 0.3-1.5%) among patients with a known result. Seven tumor samples were positive for RET rearrangements (vandetanib, n = 3; comparator, n = 4). 2.8% (n = 26) of samples had RET amplification (innumerable RET clusters, or ≥7 copies in > 10% of tumor cells), 8.1% (n = 76) had low RET gene copy number gain (4-6 copies in ≥40% of tumor cells) and 8.3% (n = 92) were RET expression positive (signal intensity ++ or +++ in >10% of tumor cells). Of RET-rearrangement-positive patients, none had an objective response in the vandetanib arm and one patient responded in the comparator arm. Radiologic evidence of tumor shrinkage was observed in two patients treated with vandetanib and one treated with comparator drug. The objective response rate was similar in the vandetanib and comparator arms for patients positive for RET copy number gains or RET protein expression. We have identified prevalence for three RET biomarkers in a population predominated by non-Asians and smokers. RET rearrangement prevalence was lower than previously reported. We found no evidence of a differential benefit for efficacy by IHC and RET gene copy number gains. The low prevalence of RET rearrangements (0.7%) prevents firm conclusions regarding association of vandetanib treatment with

  6. Enabling the Direct Detection of Earth-Sized Exoplanets with the LBTI HOSTS Project: A Progress Report

    NASA Technical Reports Server (NTRS)

    Danchi, W.; Bailey, V.; Bryden, G.; Defrere, D.; Ertel, S.; Haniff, C.; Hinz, P.; Kennedy, G.; Mennesson, B.; Millan-Gabet, R.; hide

    2016-01-01

    NASA has funded a project called the Hunt for Observable Signatures of Terrestrial Systems (HOSTS) to survey nearby solar type stars to determine the amount of warm zodiacal dust in their habitable zones. The goal is not only to determine the luminosity distribution function but also to know which individual stars have the least amount of zodiacal dust. It is important to have this information for future missions that directly image exoplanets as this dust is the main source of astrophysical noise for them. The HOSTS project utilizes the Large Binocular Telescope Interferometer (LBTI), which consists of two 8.4-m apertures separated by a 14.4-m baseline on Mt. Graham, Arizona. The LBTI operates in a nulling mode in the mid-infrared spectral window (8-13 micrometers), in which light from the two telescopes is coherently combined with a 180 degree phase shift between them, producing a dark fringe at the location of the target star. In doing so the starlight is greatly reduced, increasing the contrast, analogous to a coronagraph operating at shorter wavelengths. The LBTI is a unique instrument, having only three warm reflections before the starlight reaches cold mirrors, giving it the best photometric sensitivity of any interferometer operating in the mid-infrared. It also has a superb Adaptive Optics (AO) system giving it Strehl ratios greater than 98% at 10 micrometers. In 2014 into early 2015 LBTI was undergoing commissioning. The HOSTS. project team passed its Operational Readiness Review (ORR) in April 2015. The team recently published papers on the target sample, modeling of the nulled disk images, and initial results such as the detection of warm dust around eta Corvi. Recently a paper was published on the data pipeline and on-sky performance. An additional paper is in preparation on Beta Leo. We will discuss the scientific and programmatic context for the LBTI project, and we will report recent progress, new results, and plans for the science verification

  7. BATMAN: Bayesian Technique for Multi-image Analysis

    NASA Astrophysics Data System (ADS)

    Casado, J.; Ascasibar, Y.; García-Benito, R.; Guidi, G.; Choudhury, O. S.; Bellocchi, E.; Sánchez, S. F.; Díaz, A. I.

    2017-04-01

    This paper describes the Bayesian Technique for Multi-image Analysis (BATMAN), a novel image-segmentation technique based on Bayesian statistics that characterizes any astronomical data set containing spatial information and performs a tessellation based on the measurements and errors provided as input. The algorithm iteratively merges spatial elements as long as they are statistically consistent with carrying the same information (I.e. identical signal within the errors). We illustrate its operation and performance with a set of test cases including both synthetic and real integral-field spectroscopic data. The output segmentations adapt to the underlying spatial structure, regardless of its morphology and/or the statistical properties of the noise. The quality of the recovered signal represents an improvement with respect to the input, especially in regions with low signal-to-noise ratio. However, the algorithm may be sensitive to small-scale random fluctuations, and its performance in presence of spatial gradients is limited. Due to these effects, errors may be underestimated by as much as a factor of 2. Our analysis reveals that the algorithm prioritizes conservation of all the statistically significant information over noise reduction, and that the precise choice of the input data has a crucial impact on the results. Hence, the philosophy of BaTMAn is not to be used as a 'black box' to improve the signal-to-noise ratio, but as a new approach to characterize spatially resolved data prior to its analysis. The source code is publicly available at http://astro.ft.uam.es/SELGIFS/BaTMAn.

  8. Evaluation of Techniques Used to Estimate Cortical Feature Maps

    PubMed Central

    Katta, Nalin; Chen, Thomas L.; Watkins, Paul V.; Barbour, Dennis L.

    2011-01-01

    Functional properties of neurons are often distributed nonrandomly within a cortical area and form topographic maps that reveal insights into neuronal organization and interconnection. Some functional maps, such as in visual cortex, are fairly straightforward to discern with a variety of techniques, while other maps, such as in auditory cortex, have resisted easy characterization. In order to determine appropriate protocols for establishing accurate functional maps in auditory cortex, artificial topographic maps were probed under various conditions, and the accuracy of estimates formed from the actual maps was quantified. Under these conditions, low-complexity maps such as sound frequency can be estimated accurately with as few as 25 total samples (e.g., electrode penetrations or imaging pixels) if neural responses are averaged together. More samples are required to achieve the highest estimation accuracy for higher complexity maps, and averaging improves map estimate accuracy even more than increasing sampling density. Undersampling without averaging can result in misleading map estimates, while undersampling with averaging can lead to the false conclusion of no map when one actually exists. Uniform sample spacing only slightly improves map estimation over nonuniform sample spacing typical of serial electrode penetrations. Tessellation plots commonly used to visualize maps estimated using nonuniform sampling are always inferior to linearly interpolated estimates, although differences are slight at higher sampling densities. Within primary auditory cortex, then, multiunit sampling with at least 100 samples would likely result in reasonable feature map estimates for all but the highest complexity maps and the highest variability that might be expected. PMID:21889537

  9. Do quality improvement systems improve health library services? A systematic review.

    PubMed

    Gray, Hannah; Sutton, Gary; Treadway, Victoria

    2012-09-01

    A turbulent financial and political climate requires health libraries to be more accountable than ever. Quality improvement systems are widely considered a 'good thing to do', but do they produce useful outcomes that can demonstrate value? To undertake a systematic review to identify which aspects of health libraries are being measured for quality, what tools are being used and what outcomes are reported following utilisation of quality improvement systems. Many health libraries utilise quality improvement systems without translating the data into service improvements. Included studies demonstrate that quality improvement systems produce valuable outcomes including a positive impact on strategic planning, promotion, new and improved services and staff development. No impact of quality improvement systems on library users or patients is reported in the literature. The literature in this area is sparse and requires updating. We recommend further primary research is conducted in health libraries focusing upon the outcomes of utilising quality improvement systems. An exploration of quality improvement systems in other library sectors may also provide valuable insight for health libraries. © 2012 The authors. Health Information and Libraries Journal © 2012 Health Libraries Group.

  10. Conference summary

    NASA Astrophysics Data System (ADS)

    Harwit, Martin

    To do justice to so many interesting contributions, both in the form of papers presented as talks and posters represented only by titles in these proceedings, will be difficult. Rather than attempting to list contributions from the individual areas in a representative fashion, I will attempt to see how a few of the striking contributions fit into, or alter, our views on major questions we have been trying to answer during the past few decades — questions dealing with the structure and evolution of the universe, the formation of galaxies and stars, and the origins of the solar system, in short everything from Comets to Cosmology — though I will reverse the order, starting here with cosmological questions and ending up with comets, or rather with zodiacal dust.

  11. Sources of cosmic dust in the Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Carrillo-Sánchez, J. D.; Nesvorný, D.; Pokorný, P.; Janches, D.; Plane, J. M. C.

    2016-12-01

    There are four known sources of dust in the inner solar system: Jupiter Family comets, asteroids, Halley Type comets, and Oort Cloud comets. Here we combine the mass, velocity, and radiant distributions of these cosmic dust populations from an astronomical model with a chemical ablation model to estimate the injection rates of Na and Fe into the Earth's upper atmosphere, as well as the flux of cosmic spherules to the surface. Comparing these parameters to lidar observations of the vertical Na and Fe fluxes above 87.5 km, and the measured cosmic spherule accretion rate at South Pole, shows that Jupiter Family Comets contribute (80 ± 17)% of the total input mass (43 ± 14 t d-1), in good accord with Cosmic Background Explorer and Planck observations of the zodiacal cloud.

  12. UV spectroscopy with the CETUS multi-object spectrometer

    NASA Astrophysics Data System (ADS)

    Kendrick, Stephen E.; Woodruff, Robert; Hull, Anthony; Heap, Sara; Kutyrev, Alexander; Purves, Lloyd; Danchi, William

    2018-01-01

    The ultraviolet multi-object spectrograph (MOS) for the Cosmic Evolution Through UV Spectroscopy (CETUS) concept is a slit-based instrument allowing multiple simultaneous observations over a wide field of view. The UV MOS will be able to target up to 100 objects at a time without the issues of confusion with nearby sources or unwanted background like zodiacal stray light. The multiplexing will allow over 100,000 galaxies to be observed over a typical mission lifetime which greatly enhances the scientific yield. The MOS utilizes a next-generation micro-shutter array, an efficient aspheric Offner-like spectrometer design with a convex grating, and nanotube light traps for suppressing unwanted wavelengths. The optical coatings are also designed for optimizing the UV throughput while minimizing out-of-band signal at the detector.

  13. Astronomy, Astrology, and Medicine

    NASA Astrophysics Data System (ADS)

    Greenbaum, Dorian Gieseler

    Astronomy and astrology were combined with medicine for thousands of years. Beginning in Mesopotamia in the second millennium BCE and continuing into the eighteenth century, medical practitioners used astronomy/astrology as an important part of diagnosis and prescription. Throughout this time frame, scientists cited the similarities between medicine and astrology, in addition to combining the two in practice. Hippocrates and Galen based medical theories on the relationship between heavenly bodies and human bodies. In an enduring cultural phenomenon, parts of the body as well as diseases were linked to zodiac signs and planets. In Renaissance universities, astronomy and astrology were studied by students of medicine. History records a long tradition of astrologer-physicians. This chapter covers the topic of astronomy, astrology, and medicine from the Old Babylonian period to the Enlightenment.

  14. Test results of Spacelab 2 infrared telescope focal plane. [photoconductive detector fabrication and JFET transimpedance amplifier design

    NASA Technical Reports Server (NTRS)

    Young, E. T.; Rieke, G. H.; Gautier, T. N.; Hoffmann, W. F.; Low, F. J.; Poteet, W.; Fazio, G. G.; Koch, D.; Traub, W. A.; Urban, E. W.

    1981-01-01

    The small helium cooled infrared telescope for Spacelab 2 is designed for sensitive mapping of extended, low-surface-brightness celestial sources as well as highly sensitive investigations of the shuttle contamination environment (FPA) for this mission is described as well as the design for a thermally isolated, self-heated J-FET transimpedance amplifier. This amplifier is Johnson noise limited for feedback resistances from less than 10 to the 8th power Omega to greater than 2 x 10 to the 10th power Omega at T = 4.2K. Work on the focal plane array is complete. Performance testing for qualification of the flight hardware is discussed, and results are presented. All infrared data channels are measured to be background limited by the expected level of zodiacal emission.

  15. Dust evolution from comets

    NASA Technical Reports Server (NTRS)

    Sekanina, Z.

    1976-01-01

    The studies of the evolution of cometary debris are reviewed. The subject is divided into three major sections: (1) the developments in the immediate vicinity of the cometary nucleus, which is the source of the dust; (2) the formation of the dust tail; and (3) the blending of the debris with the dust component of interplanetary matter. The importance of the physical theory of comets is emphasized for the understanding of the early phase of evolution. A physico-dynamical model designed to analyze the particle-emission mechanism from the distribution of light in the dust tail is described and the results are presented. Increased attention is paid to large particles because of their importance for the evolution of the zodiacal cloud. Finally, implications are discussed for the future in situ investigations of comets.

  16. [The celestial phenomena in A. Dürer's engraving Melancholia I].

    PubMed

    Weitzel, Hans

    2009-01-01

    The celestial body of Dürer's engraving Melencolia I is connected with his painting of a meteor, the Raveningham-painting; it is shown that the origin of this painting owns to the impact of the meteor of Ensisheim in 1492. Until now the celestial body, the balance, and the magic square are nearly consistently interpreted as the planet Saturn, the zodiac sign Libra, and the planet Jupiter, and the melancholy woman is subject to these heavenly bodies. Consequently, neoplatonic astrology has been the main focus of the engraving; including the rainbow, the engraving has also been interpreted biblically. The present paper, however, places emphasis on problems of the geometry as the reason of melancholy. Any astronomical meaning of the configuration of the numbers of the magic square is discarded.

  17. New meteoroid model predictions for directional impacts on LDEF

    NASA Technical Reports Server (NTRS)

    Divine, Neil; Agueero, Rene C.

    1993-01-01

    An extensive body of data, from meteors, zodiacal light, spacecraft-borne impact detectors (Helios, Pioneer, Galileo, Ulysses), and other sources, forms the basis of a new numerical model for the distributions of interplanetary meteoroids. For each of the five populations in this model it is possible to evaluate meteoroid concentration and flux for oriented surfaces or detectors having arbitrary position and velocity in interplanetary space. For a spacecraft in geocentric orbit the effects of gravitational focussing and shielding by the Earth have been newly derived with full attention to the directionality of the particles, both on approach (i.e., relative to a massless Earth) and at the target. This modeling approach was exercised to provide an estimate of meteoroid fluence for each of several oriented surfaces on LDEF.

  18. Results of observations of the dust distribution in the F-corona of the sun

    NASA Astrophysics Data System (ADS)

    Shestakova, L. I.; Demchenko, B. I.

    2016-03-01

    The results of modeling of the distribution of dust in the circumsolar zone are presented. The dust distribution was retrieved from observations of the line-of-sight velocities in the F-corona to the distances of 7-11 solar radii during the total eclipses of the Sun in different years: on July 31, 1981; August 11, 1991; March 29, 2006; and August 1, 2008. Comparison of the results has shown that the dust composition varies from year to year and the dust is dynamically nonuniform. In addition to the dust related to the zodiacal cloud and concentrating to the ecliptic plane, the dust of retrograde motion and the ejections and accretion in the polar regions are observed. From the results of observations of eclipses on July 31, 1981, August 11, 1991, and August 1, 2008, the east-west asymmetry in a sign of the line-of-sight velocities was detected: they are negative to the east of the Sun and positive to the west. Such distribution of the velocities is indicative of the nearecliptic orbital dust motion, whose direction coincides with that of the motion of the planets. In the course of the eclipse of March 29, 2006, almost no dynamical connection with the zodiacal cloud was found. At the same time, the direction, where the observed velocities are largest in value and opposite in sign on opposite sides of the Sun, was determined, which provides evidence of the orbital motion deviating from the ecliptic plane. The results of observations in 2006 reveal a clear genetic connection of the observed orbital motion of dust with the parent comets of the Kreutz family found near the Sun close to the eclipse date. The velocities observed near the symmetry line in the plane of the sky grow by absolute value with increasing the elongation, which may take place, if the line of sight croßses an empty zone that is free of dust. The modeling of the data of observations near the symmetry plane allowed the parameters of the dust distribution near the sublimation zone to be obtained. In

  19. Accelerating quality improvement within your organization: Applying the Model for Improvement.

    PubMed

    Crowl, Ashley; Sharma, Anita; Sorge, Lindsay; Sorensen, Todd

    2015-01-01

    To discuss the fundamentals of the Model for Improvement and how the model can be applied to quality improvement activities associated with medication use, including understanding the three essential questions that guide quality improvement, applying a process for actively testing change within an organization, and measuring the success of these changes on care delivery. PubMed from 1990 through April 2014 using the search terms quality improvement, process improvement, hospitals, and primary care. At the authors' discretion, studies were selected based on their relevance in demonstrating the quality improvement process and tests of change within an organization. Organizations are continuously seeking to enhance quality in patient care services, and much of this work focuses on improving care delivery processes. Yet change in these systems is often slow, which can lead to frustration or apathy among frontline practitioners. Adopting and applying the Model for Improvement as a core strategy for quality improvement efforts can accelerate the process. While the model is frequently well known in hospitals and primary care settings, it is not always familiar to pharmacists. In addition, while some organizations may be familiar with the "plan, do, study, act" (PDSA) cycles-one element of the Model for Improvement-many do not apply it effectively. The goal of the model is to combine a continuous process of small tests of change (PDSA cycles) within an overarching aim with a longitudinal measurement process. This process differs from other forms of improvement work that plan and implement large-scale change over an extended period, followed by months of data collection. In this scenario it may take months or years to determine whether an intervention will have a positive impact. By following the Model for Improvement, frontline practitioners and their organizational leaders quickly identify strategies that make a positive difference and result in a greater degree of

  20. Integrating empowerment evaluation and quality improvement to achieve healthcare improvement outcomes

    PubMed Central

    Wandersman, Abraham; Alia, Kassandra Ann; Cook, Brittany; Ramaswamy, Rohit

    2015-01-01

    While the body of evidence-based healthcare interventions grows, the ability of health systems to deliver these interventions effectively and efficiently lags behind. Quality improvement approaches, such as the model for improvement, have demonstrated some success in healthcare but their impact has been lessened by implementation challenges. To help address these challenges, we describe the empowerment evaluation approach that has been developed by programme evaluators and a method for its application (Getting To Outcomes (GTO)). We then describe how GTO can be used to implement healthcare interventions. An illustrative healthcare quality improvement example that compares the model for improvement and the GTO method for reducing hospital admissions through improved diabetes care is described. We conclude with suggestions for integrating GTO and the model for improvement. PMID:26178332

  1. On the mechanochemical theory of biological pattern formation with application to vasculogenesis.

    PubMed

    Murray, James D

    2003-02-01

    We first describe the Murray-Oster mechanical theory of pattern formation, the biological basis of which is experimentally well documented. The model quantifies the interaction of cells and the extracellular matrix via the cell-generated forces. The model framework is described in quantitative detail. Vascular endothelial cells, when cultured on gelled basement membrane matrix, rapidly aggregate into clusters while deforming the matrix into a network of cord-like structures tessellating the planar culture. We apply the mechanical theory of pattern formation to this culture system and show that neither strain-biased anisotropic cell traction nor cell migration are necessary for pattern formation: isotropic, strain-stimulated cell traction is sufficient to form the observed patterns. Predictions from the model were confirmed experimentally.

  2. Special solutions to Chazy equation

    NASA Astrophysics Data System (ADS)

    Varin, V. P.

    2017-02-01

    We consider the classical Chazy equation, which is known to be integrable in hypergeometric functions. But this solution has remained purely existential and was never used numerically. We give explicit formulas for hypergeometric solutions in terms of initial data. A special solution was found in the upper half plane H with the same tessellation of H as that of the modular group. This allowed us to derive some new identities for the Eisenstein series. We constructed a special solution in the unit disk and gave an explicit description of singularities on its natural boundary. A global solution to Chazy equation in elliptic and theta functions was found that allows parametrization of an arbitrary solution to Chazy equation. The results have applications to analytic number theory.

  3. Comprehensive mutagenesis of HIV-1 protease: a computational geometry approach.

    PubMed

    Masso, Majid; Vaisman, Iosif I

    2003-05-30

    A computational geometry technique based on Delaunay tessellation of protein structure, represented by C(alpha) atoms, is used to study effects of single residue mutations on sequence-structure compatibility in HIV-1 protease. Profiles of residue scores derived from the four-body statistical potential are constructed for all 1881 mutants of the HIV-1 protease monomer and compared with the profile of the wild-type protein. The profiles for an isolated monomer of HIV-1 protease and the identical monomer in a dimeric state with an inhibitor are analyzed to elucidate changes to structural stability. Protease residues shown to undergo the greatest impact are those forming the dimer interface and flap region, as well as those known to be involved in inhibitor binding.

  4. Supernova Remnant Evolving in Wind-Blown Bubbles: A Case Study of Kes 27

    NASA Astrophysics Data System (ADS)

    Li, Jiangtao

    2013-10-01

    Mixed-morphology (MM) SNRs represent SN explosion in wind-blown bubbles. They are thus good places to study the interaction between massive stellar winds, SNRs, and the surrounding ISM. We propose a 50ks XMM-Newton observation of a peculiar MM SNR, Kes 27. We will map out the spectral parameters in tessellated meshes and construct EW maps of some emission lines with our newly developed spatially-resolved spectroscopy method. These analyses will help us to understand the unusual properties of this MM SNR, such as the X-ray bright outer shell, shell-like interior, and strong NE-SW asymmetry in morphology. We will also search for evidence of over-ionization state plasma and coherent X-ray features associated with the shell of the HI cavity.

  5. Origami Multistability: From Single Vertices to Metasheets

    NASA Astrophysics Data System (ADS)

    Waitukaitis, Scott; Menaut, Rémi; Chen, Bryan Gin-ge; van Hecke, Martin

    2015-02-01

    We show that the simplest building blocks of origami-based materials—rigid, degree-four vertices—are generically multistable. The existence of two distinct branches of folding motion emerging from the flat state suggests at least bistability, but we show how nonlinearities in the folding motions allow generic vertex geometries to have as many as five stable states. In special geometries with collinear folds and symmetry, more branches emerge leading to as many as six stable states. Tuning the fold energy parameters, we show how monostability is also possible. Finally, we show how to program the stability features of a single vertex into a periodic fold tessellation. The resulting metasheets provide a previously unanticipated functionality—tunable and switchable shape and size via multistability.

  6. The ``False Colour'' Problem

    NASA Astrophysics Data System (ADS)

    Serra, Jean

    The emergence of new data in multidimensional function lattices is studied. A typical example is the apparition of false colours when (R,G,B) images are processed. Two lattice models are specially analysed. Firstly, one considers a mixture of total and marginal orderings where the variations of some components are governed by other ones. This constraint yields the “pilot lattices”. The second model is a cylindrical polar representation in n dimensions. In this model, data that are distributed on the unit sphere of n - 1 dimensions need to be ordered. The proposed orders, and lattices are specific to each image. They are obtained from Voronoi tesselation of the unit sphere The case of four dimensions is treated in detail and illustrated.

  7. Surface reconstruction from scattered data through pruning of unstructured grids

    NASA Technical Reports Server (NTRS)

    Maksymiuk, C. M.; Merriam, M. L.

    1991-01-01

    This paper describes an algorithm for reconstructing a surface from a randomly digitized object. Scan data (treated as a cloud of points) is first tesselated out to its convex hull using Delaunay triangulation. The line-of-sight between each surface point and the scanning device is traversed, and any tetrahedra which are pierced by it are removed. The remaining tetrahedra form an approximate solid model of the scanned object. Due to the inherently limited resolution of any scan, this algorithm requires two additional procedures to produce a smooth, polyhedral surface: one process removes long, narrow tetrahedra which span indentations in the surface between digitized points; the other smooths sharp edges. The results for a moderately resolved sample body and a highly resolved aircraft are displayed.

  8. LLNL-G3Dv3: Global P wave tomography model for improved regional and teleseismic travel time prediction: LLNL-G3DV3---GLOBAL P WAVE TOMOGRAPHY

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Simmons, N. A.; Myers, S. C.; Johannesson, G.

    [1] We develop a global-scale P wave velocity model (LLNL-G3Dv3) designed to accurately predict seismic travel times at regional and teleseismic distances simultaneously. The model provides a new image of Earth's interior, but the underlying practical purpose of the model is to provide enhanced seismic event location capabilities. The LLNL-G3Dv3 model is based on ∼2.8 millionP and Pnarrivals that are re-processed using our global multiple-event locator called Bayesloc. We construct LLNL-G3Dv3 within a spherical tessellation based framework, allowing for explicit representation of undulating and discontinuous layers including the crust and transition zone layers. Using a multiscale inversion technique, regional trendsmore » as well as fine details are captured where the data allow. LLNL-G3Dv3 exhibits large-scale structures including cratons and superplumes as well numerous complex details in the upper mantle including within the transition zone. Particularly, the model reveals new details of a vast network of subducted slabs trapped within the transition beneath much of Eurasia, including beneath the Tibetan Plateau. We demonstrate the impact of Bayesloc multiple-event location on the resulting tomographic images through comparison with images produced without the benefit of multiple-event constraints (single-event locations). We find that the multiple-event locations allow for better reconciliation of the large set of direct P phases recorded at 0–97° distance and yield a smoother and more continuous image relative to the single-event locations. Travel times predicted from a 3-D model are also found to be strongly influenced by the initial locations of the input data, even when an iterative inversion/relocation technique is employed.« less

  9. Improved physical fitness correlates with improved cognition in multiple sclerosis.

    PubMed

    Beier, Meghan; Bombardier, Charles H; Hartoonian, Narineh; Motl, Robert W; Kraft, George H

    2014-07-01

    To determine whether there is an association between improvements in objective measures of physical fitness and performance on cognitive tests in people with multiple sclerosis (MS). Post hoc correlational analysis in which people demonstrating physical improvement were compared with those not demonstrating physical improvement. Individuals with MS residing in the community. Adults with clinically confirmed MS (N=88) who participated in a controlled trial of a telephone-based health promotion intervention, chose to work on exercise, and completed the pre- and postintervention assessments. Participants were measured for strength (isokinetic dynamometer), aerobic fitness (bicycle ergometer), and cognition (Paced Auditory Serial Addition Test [PASAT], Trail Making Test [TMT]) at baseline and 12 weeks later. Change in fitness was calculated by subtracting each participant's baseline score from the outcome score, and then transforming the difference to a z score. Individuals with a z score ≥1 on any fitness measure were placed in the physically improved group (n=25). All others were in the physically not improved group (n=57). After controlling for covariates (age, sex, ethnicity, education, disease activity, MS type), there was a significant group-by-time interaction, suggesting that cognitive functioning changed over time based on level of fitness. Participants in the physically improved group demonstrated improved performance on measures of executive functioning after 12 weeks of exercise. The results of this study lend support to the hypothesis that change in fitness is associated with improved executive functioning in people with MS. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  10. Comparison of clinical features and 3-month treatment response among three different choroidal thickness groups in polypoidal choroidal vasculopathy.

    PubMed

    Kong, Mingui; Kim, Sung Min; Ham, Don-Il

    2017-01-01

    Eyes with polypoidal choroidal vasculopathy (PCV) were recently reported to have various choroidal thickness, and choroidal thickness might be associated with visual outcome in the treatment of many retinal disorders. The range of subfoveal choroidal thickness (SFCT), clinical features, and 3-month treatment response among three groups having different range of SFCT were investigated in PCV eyes. In 78 treatment-naïve eyes with PCV, SFCT was measured using optical coherence tomography. Eyes were classified into thin, medium, and thick groups, using mean and one standard deviation of SFCT. Clinical features and imaging findings were compared among the three groups. Some eyes were treated with three consecutive monthly injection of anti-vascular endothelial growth factor (VEGF) as an initial treatment. They were also classified into three thickness groups, and the short-term post-treatment improvement in visual acuity and central retinal thickness were compared among groups. The mean SFCT was 271.9 ± 135.6 μm. Twelve, 53, and 13 eyes were classified into thin (<136.3 μm), medium (136.3-407.5 μm), and thick (>407.5 μm) groups, respectively. The thin group showed older age, lower visual acuity, and a higher prevalence of fundus tessellation than the other two groups (P <0.05). In multiple linear regression analyses, baseline BCVA was correlated with baseline SFCT. Forty-six eyes completed three consecutive anti-VEGF treatments. The thin group showed no visual improvement after treatment (P = 0.141), unlike the other two groups showing visual improvement (P<0.05). Eyes with PCV have a broad range of SFCT, and PCV eyes with a thin choroid manifest worse visual function than eyes with a medium or thick choroid.

  11. Improvement Science Meets Improvement Scholarship: Reframing Research for Better Healthcare.

    PubMed

    Cribb, Alan

    2018-06-01

    In this editorial essay I explore the possibilities of 'improvement scholarship' in order to set the scene for the theme of, and the other papers in, this issue. I contrast a narrow conception of quality improvement (QI) research with a much broader and more inclusive conception, arguing that we should greatly extend the existing dialogue between 'problem-solving' and 'critical' currents in improvement research. I have in mind the potential for building a much larger conversation between those people in 'improvement science' who are expressly concerned with tackling the problems facing healthcare and the wider group of colleagues who are engaged in health-related scholarship but who do not see themselves as particularly interested in quality improvement, indeed who may be critical of the language or concerns of QI. As one contribution to that conversation I suggest that that the increasing emphasis on theory and rigour in improvement research should include more focus on normative theory and rigour. The remaining papers in the issue are introduced including the various ways in which they handle the 'implicit normativity' of QI research and practice, and the linked theme of combining relatively 'tidy' and potentially 'unruly' forms of knowledge.

  12. Continual improvement plan

    NASA Technical Reports Server (NTRS)

    1994-01-01

    NASA's approach to continual improvement (CI) is a systems-oriented, agency-wide approach that builds on the past accomplishments of NASA Headquarters and its field installations and helps achieve NASA's vision, mission, and values. The NASA of the future will fully use the principles of continual improvement in every aspect of its operations. This NASA CI plan defines a systematic approach and a model for continual improvement throughout NASA, stressing systems integration and optimization. It demonstrates NASA's constancy of purpose for improvement - a consistent vision of NASA as a worldwide leader in top-quality science, technology, and management practices. The CI plan provides the rationale, structures, methods, and steps, and it defines NASA's short term (1-year) objectives for improvement. The CI plan presents the deployment strategies necessary for cascading the goals and objectives throughout the agency. It also provides guidance on implementing continual improvement with participation from top leadership and all levels of employees.

  13. Applications of process improvement techniques to improve workflow in abdominal imaging.

    PubMed

    Tamm, Eric Peter

    2016-03-01

    Major changes in the management and funding of healthcare are underway that will markedly change the way radiology studies will be reimbursed. The result will be the need to deliver radiology services in a highly efficient manner while maintaining quality. The science of process improvement provides a practical approach to improve the processes utilized in radiology. This article will address in a step-by-step manner how to implement process improvement techniques to improve workflow in abdominal imaging.

  14. Improved Electrophoresis Cell

    NASA Technical Reports Server (NTRS)

    Rhodes, P. H.; Snyder, R. S.

    1982-01-01

    Several proposed modifications are expected to improve performance of a continous-flow electrophoresis cell. Changes would allow better control of buffer flow and would increase resolution by suppressing thermal gradients. Improved electrophoresis device would have high resolution and be easy to operate. Improvements would allow better flow control and heat dissipation.

  15. Improving HRD Practice.

    ERIC Educational Resources Information Center

    Gilley, Jerry W.

    This book provides human resource development (HRD) professionals with a practical approach for improving the way they practice their profession and presents a four-part framework for improving HRD practice. Each of the book's four parts is dedicated to one part of the framework: examining HRD strategy; improving perceptions of HRD; improving…

  16. Integrating empowerment evaluation and quality improvement to achieve healthcare improvement outcomes.

    PubMed

    Wandersman, Abraham; Alia, Kassandra Ann; Cook, Brittany; Ramaswamy, Rohit

    2015-10-01

    While the body of evidence-based healthcare interventions grows, the ability of health systems to deliver these interventions effectively and efficiently lags behind. Quality improvement approaches, such as the model for improvement, have demonstrated some success in healthcare but their impact has been lessened by implementation challenges. To help address these challenges, we describe the empowerment evaluation approach that has been developed by programme evaluators and a method for its application (Getting To Outcomes (GTO)). We then describe how GTO can be used to implement healthcare interventions. An illustrative healthcare quality improvement example that compares the model for improvement and the GTO method for reducing hospital admissions through improved diabetes care is described. We conclude with suggestions for integrating GTO and the model for improvement. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  17. Improving Quality in Education: Dynamic Approaches to School Improvement

    ERIC Educational Resources Information Center

    Creemers, Bert P. M.; Kyriakides, Leonidas

    2011-01-01

    This book explores an approach to school improvement that merges the traditions of educational effectiveness research and school improvement efforts. It displays how the dynamic model, which is theoretical and empirically validated, can be used in both traditions. Each chapter integrates evidence from international and national studies, showing…

  18. Teaching quality improvement.

    PubMed

    Murray, Marry Ellen; Douglas, Stephen; Girdley, Diana; Jarzemsky, Paula

    2010-08-01

    Practicing nurses are required to engage in quality improvement work as a part of their clinical practice, but few undergraduate nursing education programs offer course work and applied experience in this area. This article presents a description of class content and teaching strategies, assignments, and evaluation strategies designed to achieve the Quality and Safety Education in Nursing competencies related to quality improvement and interdisciplinary teams. Students demonstrate their application of the quality improvement process by designing and implementing a small-scale quality improvement project that they report in storyboard format on a virtual conference Web site.

  19. Lessons Learned on Stage: How Improv Can Improve Science Communication

    NASA Astrophysics Data System (ADS)

    Wong, G. J.; Kohn, C.; McPeek, M. A.; Serrell, N.

    2014-12-01

    A challenge facing STEM graduate students is the daunting task of communicating their research to a non-specialist audience. Strategies that work well in lab group meetings, such as using acronyms and jargon, do not work in the real world. Ideally, scientists should directly connect with any audience, responding spontaneously and actively, distilling their messages into conversational morsels that resonate with that audience. Scientists should listen. This presentation highlights a 10-week, interdisciplinary graduate course at Dartmouth College that teaches methods for communicating science with clarity, vividness, and emotion. The course was developed in partnership with Stony Brook University's Alan Alda Center for Communicating Science, and emphasizes story-telling, two-way communication, active listening, and so much more. Effective message development and communication skills - spontaneity, authenticity, and connectivity - are honed through improvisational theater exercises. One might ask, "why improv?" As a co-developer/co-instructor of this graduate course and a Ph.D. candidate in Earth Sciences, my response is, "why not improv?" Improv is acting without a script. It is also underground rap battles, baking from scratch, and playing jazz flute. Improv is Macguyver. Improv is not any one particular thing so much as it is a process through which we do things. Improv can teach us a lot: how to play, how to feel comfortable and present even while flailing, and how to truly listen.

  20. Improving a Dental School's Clinic Operations Using Lean Process Improvement.

    PubMed

    Robinson, Fonda G; Cunningham, Larry L; Turner, Sharon P; Lindroth, John; Ray, Deborah; Khan, Talib; Yates, Audrey

    2016-10-01

    The term "lean production," also known as "Lean," describes a process of operations management pioneered at the Toyota Motor Company that contributed significantly to the success of the company. Although developed by Toyota, the Lean process has been implemented at many other organizations, including those in health care, and should be considered by dental schools in evaluating their clinical operations. Lean combines engineering principles with operations management and improvement tools to optimize business and operating processes. One of the core concepts is relentless elimination of waste (non-value-added components of a process). Another key concept is utilization of individuals closest to the actual work to analyze and improve the process. When the medical center of the University of Kentucky adopted the Lean process for improving clinical operations, members of the College of Dentistry trained in the process applied the techniques to improve inefficient operations at the Walk-In Dental Clinic. The purpose of this project was to reduce patients' average in-the-door-to-out-the-door time from over four hours to three hours within 90 days. Achievement of this goal was realized by streamlining patient flow and strategically relocating key phases of the process. This initiative resulted in patient benefits such as shortening average in-the-door-to-out-the-door time by over an hour, improving satisfaction by 21%, and reducing negative comments by 24%, as well as providing opportunity to implement the electronic health record, improving teamwork, and enhancing educational experiences for students. These benefits were achieved while maintaining high-quality patient care with zero adverse outcomes during and two years following the process improvement project.

  1. Quality Improvement on the Acute Inpatient Psychiatry Unit Using the Model for Improvement

    PubMed Central

    Singh, Kuldeep; Sanderson, Joshua; Galarneau, David; Keister, Thomas; Hickman, Dean

    2013-01-01

    Background A need exists for constant evaluation and modification of processes within healthcare systems to achieve quality improvement. One common approach is the Model for Improvement that can be used to clearly define aims, measures, and changes that are then implemented through a plan-do-study-act (PDSA) cycle. This approach is a commonly used method for improving quality in a wide range of fields. The Model for Improvement allows for a systematic process that can be revised at set time intervals to achieve a desired result. Methods We used the Model for Improvement in an acute psychiatry unit (APU) to improve the screening incidence of abnormal involuntary movements in eligible patients—those starting or continuing on standing neuroleptics—with the Abnormal Involuntary Movement Scale (AIMS). Results After 8 weeks of using the Model for Improvement, both of the participating inpatient services in the APU showed substantial overall improvement in screening for abnormal involuntary movements using the AIMS. Conclusion Crucial aspects of a successful quality improvement initiative based on the Model for Improvement are well-defined goals, process measures, and structured PDSA cycles. Success also requires communication, organization, and participation of the entire team. PMID:24052768

  2. Quality improvement on the acute inpatient psychiatry unit using the model for improvement.

    PubMed

    Singh, Kuldeep; Sanderson, Joshua; Galarneau, David; Keister, Thomas; Hickman, Dean

    2013-01-01

    A need exists for constant evaluation and modification of processes within healthcare systems to achieve quality improvement. One common approach is the Model for Improvement that can be used to clearly define aims, measures, and changes that are then implemented through a plan-do-study-act (PDSA) cycle. This approach is a commonly used method for improving quality in a wide range of fields. The Model for Improvement allows for a systematic process that can be revised at set time intervals to achieve a desired result. We used the Model for Improvement in an acute psychiatry unit (APU) to improve the screening incidence of abnormal involuntary movements in eligible patients-those starting or continuing on standing neuroleptics-with the Abnormal Involuntary Movement Scale (AIMS). After 8 weeks of using the Model for Improvement, both of the participating inpatient services in the APU showed substantial overall improvement in screening for abnormal involuntary movements using the AIMS. Crucial aspects of a successful quality improvement initiative based on the Model for Improvement are well-defined goals, process measures, and structured PDSA cycles. Success also requires communication, organization, and participation of the entire team.

  3. Challenges of using quality improvement methods in nursing homes that "need improvement".

    PubMed

    Rantz, Marilyn J; Zwygart-Stauffacher, Mary; Flesner, Marcia; Hicks, Lanis; Mehr, David; Russell, Teresa; Minner, Donna

    2012-10-01

    Qualitatively describe the adoption of strategies and challenges experienced by intervention facilities participating in a study targeted to improve quality of care in nursing homes "in need of improvement". To describe how staff use federal quality indicator/quality measure (QI/QM) scores and reports, quality improvement methods and activities, and how staff supported and sustained the changes recommended by their quality improvement teams. A randomized, two-group, repeated-measures design was used to test a 2-year intervention for improving quality of care and resident outcomes in facilities in "need of improvement". Intervention group (n = 29) received an experimental multilevel intervention designed to help them: (1) use quality-improvement methods, (2) use team and group process for direct-care decision-making, (3) focus on accomplishing the basics of care, and (4) maintain more consistent nursing and administrative leadership committed to communication and active participation of staff in decision-making. A qualitative analysis revealed a subgroup of homes likely to continue quality improvement activities and readiness indicators of homes likely to improve: (1) a leadership team (nursing home administrator, director of nurses) interested in learning how to use their federal QI/QM reports as a foundation for improving resident care and outcomes; (2) one of the leaders to be a "change champion" and make sure that current QI/QM reports are consistently printed and shared monthly with each nursing unit; (3) leaders willing to involve all staff in the facility in educational activities to learn about the QI/QM process and the reports that show how their facility compares with others in the state and nation; (4) leaders willing to plan and continuously educate new staff about the MDS and federal QI/QM reports and how to do quality improvement activities; (5) leaders willing to continuously involve all staff in quality improvement committee and team activities so

  4. 76 FR 41246 - Pesticide Program Dialogue Committee, Pesticide Registration Improvement Act Process Improvement...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-13

    ... Committee, Pesticide Registration Improvement Act Process Improvement Workgroup; Notice of Public Meeting...) Process Improvement Work Group. EPA plans to meet its ESA consultation obligations through the pesticide... a pesticide during the registration review process. This meeting of the PRIA Process Improvement...

  5. Sources of cosmic dust in the Earth's atmosphere.

    PubMed

    Carrillo-Sánchez, J D; Nesvorný, D; Pokorný, P; Janches, D; Plane, J M C

    2016-12-16

    There are four known sources of dust in the inner solar system: Jupiter Family comets, asteroids, Halley Type comets, and Oort Cloud comets. Here we combine the mass, velocity, and radiant distributions of these cosmic dust populations from an astronomical model with a chemical ablation model to estimate the injection rates of Na and Fe into the Earth's upper atmosphere, as well as the flux of cosmic spherules to the surface. Comparing these parameters to lidar observations of the vertical Na and Fe fluxes above 87.5 km, and the measured cosmic spherule accretion rate at South Pole, shows that Jupiter Family Comets contribute (80 ± 17)% of the total input mass (43 ± 14 t d -1 ), in good accord with Cosmic Background Explorer and Planck observations of the zodiacal cloud.

  6. Enhancement of K - 12 Astronomy Education Through Multicultural Outreach

    NASA Astrophysics Data System (ADS)

    Yanamandra-Fisher, P. A.

    1997-12-01

    History bears out the fact that various cultures developed their own unique interpretation of the stars and the universe. Children are first introduced to the cultural lore in their pre--school years by their primary teachers --- the parents. In today's technological world, with social migration and assimilation of differing ethnic peoples into a common society, parents often neglect or ignore this valuable contibution to enhancing the child's interest in astronomy at an early age. This important contibution can be re-awakened by applying a multicultural approach to introductory astronomy/solar system science in primary grades by teachers, parents and scientists. Such an integrated approach unifies a society and instructs the child by identifying its cultural and scientific heritage. Some common examples are the interpretation of the Big Dipper, Zodiac and the planets. These and other examples will be provided along with teaching aids.

  7. Sources of cosmic dust in the Earth's atmosphere

    PubMed Central

    Carrillo‐Sánchez, J. D.; Nesvorný, D.; Pokorný, P.; Janches, D.

    2016-01-01

    Abstract There are four known sources of dust in the inner solar system: Jupiter Family comets, asteroids, Halley Type comets, and Oort Cloud comets. Here we combine the mass, velocity, and radiant distributions of these cosmic dust populations from an astronomical model with a chemical ablation model to estimate the injection rates of Na and Fe into the Earth's upper atmosphere, as well as the flux of cosmic spherules to the surface. Comparing these parameters to lidar observations of the vertical Na and Fe fluxes above 87.5 km, and the measured cosmic spherule accretion rate at South Pole, shows that Jupiter Family Comets contribute (80 ± 17)% of the total input mass (43 ± 14 t d−1), in good accord with Cosmic Background Explorer and Planck observations of the zodiacal cloud. PMID:28275286

  8. Dust evolution from comets

    NASA Technical Reports Server (NTRS)

    Sekanina, Z.

    1977-01-01

    The studies of the evolution of cometary debris are reviewed. The subject is divided into three major sections: (1) the developments in the immediate vicinity of the cometary nucleus, which is the source of the dust; (2) the formation of the dust tail; and (3) the blending of the debris with the dust component of interplanetary matter. The importance of the physical theory of comets is emphasized for the understanding of the early phase of the evolution of cometary dust. A physico-dynamical model designed to analyze the particle-emission mechanism from the distribution of light in the dust tails is described and the results are presented. Increased attention is paid to large particles because of their importance for the evolution of the zodiacal cloud. Finally, implications are discussed for the future in situ investigations of comets.

  9. Synoptic maps constructed from brightness observations of Thomson scattering by heliospheric electrons

    NASA Technical Reports Server (NTRS)

    Hick, P.; Jackson, B.; Schwenn, R.

    1991-01-01

    Observations of the Thomson scattering brightness by electrons in the inner heliosphere provide a means of probing the heliospheric electron distributions. An extensive data base of Thomson scattering observations, stretching over many years, is available from the zodiacal light photometers on board the two Helios spacecraft. A survey of these data is in progress, presenting these scattering intensities in the form of synoptic maps for successive Carrington rotations. The Thomson scattering maps reflect conditions at typically several tenths of an astronomical unit from the sun. Some representative examples from the survey in comparison with other solar/heliospheric data, such as in situ observations of the Helios plasma experiment and synoptic maps constructed from magnetic field, H alpha and K-coronameter data are presented. The comparison will provide some information about the extension of solar surface features into the inner heliosphere.

  10. New meteoroid model predictions for directional impacts on LDEF

    NASA Technical Reports Server (NTRS)

    Divine, Neil; Aguero, Rene C.

    1992-01-01

    An extensive body of data, from meteors, zodiacal light, spacecraft-borne impact detectors (helios, Pioneer, Galileo, and Ulysses), and other sources, forms the basis of a new numerical model for the distributions of interplanetary meteoroids. For each of the five populations in this model it is possible to evaluate meteoroid concentration and flux for oriented surfaces or detectors having arbitrary position and velocity in interplanetary space (Divine, 1992, in preparation). For a spacecraft in geocentric orbit, the effects of gravitational focusing and shielding by the Earth were derived with full attention to the directionality of the particles, both on approach (i.e., relative to a massless Earth) and at the target. This modeling approach was exercised to provide an estimate of meteoroid fluence for each of several oriented surfaces on the Long Duration Exposure Facility (LDEF).

  11. Continuous Quality Improvement: A Roadmap for Rural School Improvement.

    ERIC Educational Resources Information Center

    Kilmer, Lloyd C.

    A case study documented a continuous quality improvement approach to school improvement in a rural Nebraska high school over a 2-year period. Data gathered from surveys, portfolios, pilot results, and test scores indicated that the changes during the 2-year period were not dramatic, but significant and consistent with the Total Quality literature.…

  12. Improving Teaching Does Improve Teachers: Evidence from Lesson Study

    ERIC Educational Resources Information Center

    Lewis, Catherine C.; Perry, Rebecca R.; Friedkin, Shelley; Roth, Jillian R.

    2012-01-01

    The authors comment on the article by Morris and Hiebert in three ways. First, they add thoughts about why improvement efforts often focus on teachers, rather than teaching. Second, they offer evidence from U.S. lesson study research that focus on teaching can improve both students' learning and teachers' learning. Finally, they suggest that the…

  13. The persistent cosmic web and its filamentary structure - I. Theory and implementation

    NASA Astrophysics Data System (ADS)

    Sousbie, T.

    2011-06-01

    We present DisPerSE, a novel approach to the coherent multiscale identification of all types of astrophysical structures, in particular the filaments, in the large-scale distribution of the matter in the Universe. This method and the corresponding piece of software allows for a genuinely scale-free and parameter-free identification of the voids, walls, filaments, clusters and their configuration within the cosmic web, directly from the discrete distribution of particles in N-body simulations or galaxies in sparse observational catalogues. To achieve that goal, the method works directly over the Delaunay tessellation of the discrete sample and uses the Delaunay tessellation field estimator density computed at each tracer particle; no further sampling, smoothing or processing of the density field is required. The idea is based on recent advances in distinct subdomains of the computational topology, namely the discrete Morse theory which allows for a rigorous application of topological principles to astrophysical data sets, and the theory of persistence, which allows us to consistently account for the intrinsic uncertainty and Poisson noise within data sets. Practically, the user can define a given persistence level in terms of robustness with respect to noise (defined as a 'number of σ') and the algorithm returns the structures with the corresponding significance as sets of critical points, lines, surfaces and volumes corresponding to the clusters, filaments, walls and voids - filaments, connected at cluster nodes, crawling along the edges of walls bounding the voids. From a geometrical point of view, the method is also interesting as it allows for a robust quantification of the topological properties of a discrete distribution in terms of Betti numbers or Euler characteristics, without having to resort to smoothing or having to define a particular scale. In this paper, we introduce the necessary mathematical background and describe the method and implementation

  14. Parametric Grid Information in the DOE Knowledge Base: Data Preparation, Storage, and Access

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    HIPP,JAMES R.; MOORE,SUSAN G.; MYERS,STEPHEN C.

    The parametric grid capability of the Knowledge Base provides an efficient, robust way to store and access interpolatable information which is needed to monitor the Comprehensive Nuclear Test Ban Treaty. To meet both the accuracy and performance requirements of operational monitoring systems, we use a new approach which combines the error estimation of kriging with the speed and robustness of Natural Neighbor Interpolation (NNI). The method involves three basic steps: data preparation (DP), data storage (DS), and data access (DA). The goal of data preparation is to process a set of raw data points to produce a sufficient basis formore » accurate NNI of value and error estimates in the Data Access step. This basis includes a set of nodes and their connectedness, collectively known as a tessellation, and the corresponding values and errors that map to each node, which we call surfaces. In many cases, the raw data point distribution is not sufficiently dense to guarantee accurate error estimates from the NNI, so the original data set must be densified using a newly developed interpolation technique known as Modified Bayesian Kriging. Once appropriate kriging parameters have been determined by variogram analysis, the optimum basis for NNI is determined in a process they call mesh refinement, which involves iterative kriging, new node insertion, and Delauny triangle smoothing. The process terminates when an NNI basis has been calculated which will fir the kriged values within a specified tolerance. In the data storage step, the tessellations and surfaces are stored in the Knowledge Base, currently in a binary flatfile format but perhaps in the future in a spatially-indexed database. Finally, in the data access step, a client application makes a request for an interpolated value, which triggers a data fetch from the Knowledge Base through the libKBI interface, a walking triangle search for the containing triangle, and finally the NNI interpolation.« less

  15. Detection of the corrosion in reinforced concrete with GPR: the case study of the Park Guell

    NASA Astrophysics Data System (ADS)

    Sossa, Viviana; Perez-Gracia, Vega; Gonzalez-Drigo, Ramon; Caselles, Oriol; Clapes, Jaume

    2017-04-01

    Detection of corrosion is important in cultural heritage assessment. Many structures contain metallic targets embedded in masonry or mortar, and corrosion cab cause important damage. However, detection using non-destructive methods is difficult and highly localized, providing in most cases incomplete results. In order to obtain a more extended analysis, GPR was applied and evaluated to detect damage as consequence of corrosion. This technique is a non-destructive method that covers a large area of study while other methods are constrained to a small areas or specific points. Therefore, some controlled laboratory tests were designed to determine possible differences in radargrams obtained in the case of corroded and non-corroded targets. These analysis allowed to observe that the corrosion seems to increase the attenuation of the radar signal, being difficult to detect targets near the damaged bars. The results were applied to study the mosaic roofs in the Park Guell, in Barcelona. This park is one of the most important Modernista (Art Noveau) complex in Barcelona. It is characterized by structures with roofs and banks with tessellation. Some of these structures are most likely supported by metal elements, and seepage cause important damage observed over the tessellation. The objective of the study was to define the possible existence of those metallic targets, determining their location. And, in the case of existence of metallic elements, defining which are the zones more affected by corrosion. The results demonstrates the existence of metallic supports in many parts, as well as some defined areas that could be damaged. Acknowledgement: This work has been partially funded by the Spanish Government and by the European Commission with FEDER funds, through the research projects CGL2011-23621 and CGL2015-65913-P. The study is also a contribution to the EU funded COST Action TU1208, "Civil Engineering Applications of Ground Penetrating Radar", to the working group 2.2.

  16. 3D Voronoi grid dedicated software for modeling gas migration in deep layered sedimentary formations with TOUGH2-TMGAS

    NASA Astrophysics Data System (ADS)

    Bonduà, Stefano; Battistelli, Alfredo; Berry, Paolo; Bortolotti, Villiam; Consonni, Alberto; Cormio, Carlo; Geloni, Claudio; Vasini, Ester Maria

    2017-11-01

    As is known, a full three-dimensional (3D) unstructured grid permits a great degree of flexibility when performing accurate numerical reservoir simulations. However, when the Integral Finite Difference Method (IFDM) is used for spatial discretization, constraints (arising from the required orthogonality between the segment connecting the blocks nodes and the interface area between blocks) pose difficulties in the creation of grids with irregular shaped blocks. The full 3D Voronoi approach guarantees the respect of IFDM constraints and allows generation of grids conforming to geological formations and structural objects and at the same time higher grid resolution in volumes of interest. In this work, we present dedicated pre- and post-processing gridding software tools for the TOUGH family of numerical reservoir simulators, developed by the Geothermal Research Group of the DICAM Department, University of Bologna. VORO2MESH is a new software coded in C++, based on the voro++ library, allowing computation of the 3D Voronoi tessellation for a given domain and the creation of a ready to use TOUGH2 MESH file. If a set of geological surfaces is available, the software can directly generate the set of Voronoi seed points used for tessellation. In order to reduce the number of connections and so to decrease computation time, VORO2MESH can produce a mixed grid with regular blocks (orthogonal prisms) and irregular blocks (polyhedron Voronoi blocks) at the point of contact between different geological formations. In order to visualize 3D Voronoi grids together with the results of numerical simulations, the functionality of the TOUGH2Viewer post-processor has been extended. We describe an application of VORO2MESH and TOUGH2Viewer to validate the two tools. The case study deals with the simulation of the migration of gases in deep layered sedimentary formations at basin scale using TOUGH2-TMGAS. A comparison between the simulation performances of unstructured and structured

  17. A cluster-randomised quality improvement study to improve two inpatient stroke quality indicators.

    PubMed

    Williams, Linda; Daggett, Virginia; Slaven, James E; Yu, Zhangsheng; Sager, Danielle; Myers, Jennifer; Plue, Laurie; Woodward-Hagg, Heather; Damush, Teresa M

    2016-04-01

    Quality indicator collection and feedback improves stroke care. We sought to determine whether quality improvement training plus indicator feedback was more effective than indicator feedback alone in improving inpatient stroke indicators. We conducted a cluster-randomised quality improvement trial, randomising hospitals to quality improvement training plus indicator feedback versus indicator feedback alone to improve deep vein thrombosis (DVT) prophylaxis and dysphagia screening. Intervention sites received collaborative-based quality improvement training, external facilitation and indicator feedback. Control sites received only indicator feedback. We compared indicators pre-implementation (pre-I) to active implementation (active-I) and post-implementation (post-I) periods. We constructed mixed-effect logistic models of the two indicators with a random intercept for hospital effect, adjusting for patient, time, intervention and hospital variables. Patients at intervention sites (1147 admissions), had similar race, gender and National Institutes of Health Stroke Scale scores to control sites (1017 admissions). DVT prophylaxis improved more in intervention sites during active-I period (ratio of ORs 4.90, p<0.001), but did not differ in post-I period. Dysphagia screening improved similarly in both groups during active-I, but control sites improved more in post-I period (ratio of ORs 0.67, p=0.04). In logistic models, the intervention was independently positively associated with DVT performance during active-I period, and negatively associated with dysphagia performance post-I period. Quality improvement training was associated with early DVT improvement, but the effect was not sustained over time and was not seen with dysphagia screening. External quality improvement programmes may quickly boost performance but their effect may vary by indicator and may not sustain over time. Published by the BMJ Publishing Group Limited. For permission to use (where not already

  18. Sex differences in obesity related cancer incidence in relation to type 2 diabetes diagnosis (ZODIAC-49).

    PubMed

    Schrijnders, Dennis; Hendriks, Steven H; Kleefstra, Nanne; Vissers, Pauline A J; Johnson, Jeffrey A; de Bock, Geertruida H; Bilo, Henk J G; Landman, Gijs W D

    2018-01-01

    Diabetes and obesity seem to be partly overlapping risk factors for the development of obesity-related cancer (mainly breast, prostate and colorectal cancer) in patients with type 2 diabetes (T2DM). In the general population, women have a lower risk for obesity-related cancer compared to men. Previous studies involving cardiovascular disease have shown that T2DM eliminates a female advantage of lower CVD risk in the general population compared to men. It is unclear whether the same could be true for obesity-related cancer. This study aimed to this investigate obesity-related cancer incidence in women and men known with T2DM as compared to the Dutch general population. This study included 69,583 patients with T2DM selected from a prospective primary care cohort, which was linked to the Dutch National Cancer Registry to obtain cancer specific data. Obesity-related cancers included liver, kidney, colorectal, gallbladder, pancreas, ovarian, endometrial, advanced prostate cancer, post-menopausal breast cancer and oesophageal adenocarcinoma. Primary outcome was sex-stratified, age and year of cancer diagnosis adjusted standardized incidence ratios (SIRs) for three time periods: 5 years before, the year after diagnosis and the next 4 years after T2DM diagnosis. The Dutch general population was used as reference group. Women with T2DM were at an increased risk for obesity-related cancer compared to women in the general population already 5 years before diabetes diagnosis (SIR 1.77; 95%CI: 1.63-1.91). In both men and women, there was a peak in obesity-related cancer incidence following diabetes diagnosis (SIR: 1.38; 95%CI 1.11-1.64 and SIR: 2.21; 95%CI 1.94-2.30, respectively). From the second to the fifth year after diabetes diagnosis the obesity-related cancer incidence was higher in women compared to women in the general population (SIR: 2.12; 95%CI 1.94-2.30). Women with T2DM seem to have a substantially higher obesity-related cancer risk. As opposed to men, in women this risk was already increased years before diabetes diagnosis. These results could imply that a relative advantage of women in the general population with regard to cancer risk is lost in women with T2DM.

  19. Sex differences in obesity related cancer incidence in relation to type 2 diabetes diagnosis (ZODIAC-49)

    PubMed Central

    Hendriks, Steven H.; Kleefstra, Nanne; Vissers, Pauline A. J.; de Bock, Geertruida H.; Bilo, Henk J. G.; Landman, Gijs W. D.

    2018-01-01

    Background Diabetes and obesity seem to be partly overlapping risk factors for the development of obesity-related cancer (mainly breast, prostate and colorectal cancer) in patients with type 2 diabetes (T2DM). In the general population, women have a lower risk for obesity-related cancer compared to men. Previous studies involving cardiovascular disease have shown that T2DM eliminates a female advantage of lower CVD risk in the general population compared to men. It is unclear whether the same could be true for obesity-related cancer. This study aimed to this investigate obesity-related cancer incidence in women and men known with T2DM as compared to the Dutch general population. Methods This study included 69,583 patients with T2DM selected from a prospective primary care cohort, which was linked to the Dutch National Cancer Registry to obtain cancer specific data. Obesity-related cancers included liver, kidney, colorectal, gallbladder, pancreas, ovarian, endometrial, advanced prostate cancer, post-menopausal breast cancer and oesophageal adenocarcinoma. Primary outcome was sex-stratified, age and year of cancer diagnosis adjusted standardized incidence ratios (SIRs) for three time periods: 5 years before, the year after diagnosis and the next 4 years after T2DM diagnosis. The Dutch general population was used as reference group. Results Women with T2DM were at an increased risk for obesity-related cancer compared to women in the general population already 5 years before diabetes diagnosis (SIR 1.77; 95%CI: 1.63–1.91). In both men and women, there was a peak in obesity-related cancer incidence following diabetes diagnosis (SIR: 1.38; 95%CI 1.11–1.64 and SIR: 2.21; 95%CI 1.94–2.30, respectively). From the second to the fifth year after diabetes diagnosis the obesity-related cancer incidence was higher in women compared to women in the general population (SIR: 2.12; 95%CI 1.94–2.30). Conclusions Women with T2DM seem to have a substantially higher obesity-related cancer risk. As opposed to men, in women this risk was already increased years before diabetes diagnosis. These results could imply that a relative advantage of women in the general population with regard to cancer risk is lost in women with T2DM. PMID:29370205

  20. Making process improvement 'stick'.

    PubMed

    Studer, Quint

    2014-06-01

    To sustain gains from a process improvement initiative, healthcare organizations should: Explain to staff why a process improvement initiative is needed. Encourage leaders within the organization to champion the process improvement, and tie their evaluations to its outcomes. Ensure that both leaders and employees have the skills to help sustain the sought-after process improvements.

  1. Networked Improvement Communities: The Discipline of Improvement Science Meets the Power of Networks

    ERIC Educational Resources Information Center

    LeMahieu, Paul G.; Grunow, Alicia; Baker, Laura; Nordstrum, Lee E.; Gomez, Louis M.

    2017-01-01

    Purpose: The purpose of this paper is to delineate an approach to quality assurance in education called networked improvement communities (NICs) that focused on integrating the methodologies of improvement science with few of the networks. Quality improvement, the science and practice of continuously improving programs, practices, processes,…

  2. Modeling for Ultrasonic Health Monitoring of Foams with Embedded Sensors

    NASA Technical Reports Server (NTRS)

    Wang, L.; Rokhlin, S. I.; Rokhlin, Stanislav, I.

    2005-01-01

    In this report analytical and numerical methods are proposed to estimate the effective elastic properties of regular and random open-cell foams. The methods are based on the principle of minimum energy and on structural beam models. The analytical solutions are obtained using symbolic processing software. The microstructure of the random foam is simulated using Voronoi tessellation together with a rate-dependent random close-packing algorithm. The statistics of the geometrical properties of random foams corresponding to different packing fractions have been studied. The effects of the packing fraction on elastic properties of the foams have been investigated by decomposing the compliance into bending and axial compliance components. It is shown that the bending compliance increases and the axial compliance decreases when the packing fraction increases. Keywords: Foam; Elastic properties; Finite element; Randomness

  3. Point process statistics in atom probe tomography.

    PubMed

    Philippe, T; Duguay, S; Grancher, G; Blavette, D

    2013-09-01

    We present a review of spatial point processes as statistical models that we have designed for the analysis and treatment of atom probe tomography (APT) data. As a major advantage, these methods do not require sampling. The mean distance to nearest neighbour is an attractive approach to exhibit a non-random atomic distribution. A χ(2) test based on distance distributions to nearest neighbour has been developed to detect deviation from randomness. Best-fit methods based on first nearest neighbour distance (1 NN method) and pair correlation function are presented and compared to assess the chemical composition of tiny clusters. Delaunay tessellation for cluster selection has been also illustrated. These statistical tools have been applied to APT experiments on microelectronics materials. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. A modification of the fusion model for log polar coordinates

    NASA Technical Reports Server (NTRS)

    Griswold, N. C.; Weiman, Carl F. R.

    1990-01-01

    The fusion mechanism for application in stereo analysis of range restricted the depth of field and therefore required a shift variant mechanism in the peripheral area to find disparity. Misregistration was prevented by restricting the disparity detection range to a neighborhood spanned by the directional edge detection filters. This transformation was essentially accomplished by a nonuniform resampling of the original image in a horizontal direction. While this is easily implemented for digital processing, the approach does not (in the peripheral vision area) model the log-conformal mapping which is known to occur in the human mechanism. This paper therefore modifies the original fusion concept in the peripheral area to include the polar exponential grid-to-log conformal tesselation. Examples of the fusion process resulting in accurate disparity values are given.

  5. Self-organization of maze-like structures via guided wrinkling.

    PubMed

    Bae, Hyung Jong; Bae, Sangwook; Yoon, Jinsik; Park, Cheolheon; Kim, Kibeom; Kwon, Sunghoon; Park, Wook

    2017-06-01

    Sophisticated three-dimensional (3D) structures found in nature are self-organized by bottom-up natural processes. To artificially construct these complex systems, various bottom-up fabrication methods, designed to transform 2D structures into 3D structures, have been developed as alternatives to conventional top-down lithography processes. We present a different self-organization approach, where we construct microstructures with periodic and ordered, but with random architecture, like mazes. For this purpose, we transformed planar surfaces using wrinkling to directly use randomly generated ridges as maze walls. Highly regular maze structures, consisting of several tessellations with customized designs, were fabricated by precisely controlling wrinkling with the ridge-guiding structure, analogous to the creases in origami. The method presented here could have widespread applications in various material systems with multiple length scales.

  6. Geometry and design of origami bellows with tunable response

    NASA Astrophysics Data System (ADS)

    Reid, Austin; Lechenault, Frederic; Rica, Sergio; Adda-Bedia, Mokhtar

    2017-01-01

    Origami folded cylinders (origami bellows) have found increasingly sophisticated applications in space flight and medicine. In spite of this interest, a general understanding of the mechanics of an origami folded cylinder has been elusive. With a newly developed set of geometrical tools, we have found an analytic solution for all possible cylindrical rigid-face states of both Miura-ori and triangular tessellations. Although an idealized bellows in both of these families may have two allowed rigid-face configurations over a well-defined region, the corresponding physical device, limited by nonzero material thickness and forced to balance hinge and plate-bending energy, often cannot stably maintain a stowed configuration. We have identified the parameters that control this emergent bistability, and we have demonstrated the ability to design and fabricate bellows with tunable deployability.

  7. Geometry and design of origami bellows with tunable response.

    PubMed

    Reid, Austin; Lechenault, Frederic; Rica, Sergio; Adda-Bedia, Mokhtar

    2017-01-01

    Origami folded cylinders (origami bellows) have found increasingly sophisticated applications in space flight and medicine. In spite of this interest, a general understanding of the mechanics of an origami folded cylinder has been elusive. With a newly developed set of geometrical tools, we have found an analytic solution for all possible cylindrical rigid-face states of both Miura-ori and triangular tessellations. Although an idealized bellows in both of these families may have two allowed rigid-face configurations over a well-defined region, the corresponding physical device, limited by nonzero material thickness and forced to balance hinge and plate-bending energy, often cannot stably maintain a stowed configuration. We have identified the parameters that control this emergent bistability, and we have demonstrated the ability to design and fabricate bellows with tunable deployability.

  8. Zonal wavefront estimation using an array of hexagonal grating patterns

    NASA Astrophysics Data System (ADS)

    Pathak, Biswajit; Boruah, Bosanta R.

    2014-10-01

    Accuracy of Shack-Hartmann type wavefront sensors depends on the shape and layout of the lenslet array that samples the incoming wavefront. It has been shown that an array of gratings followed by a focusing lens provide a substitution for the lensslet array. Taking advantage of the computer generated holography technique, any arbitrary diffraction grating aperture shape, size or pattern can be designed with little penalty for complexity. In the present work, such a holographic technique is implemented to design regular hexagonal grating array to have zero dead space between grating patterns, eliminating the possibility of leakage of wavefront during the estimation of the wavefront. Tessellation of regular hexagonal shape, unlike other commonly used shapes, also reduces the estimation error by incorporating more number of neighboring slope values at an equal separation.

  9. CALISTO: A Cryogenic Far-Infrared/Submillimeter Observatory

    NASA Technical Reports Server (NTRS)

    Goldsmith, P. F.; Bradford, C. M.; Dragovan, M.; Khayatian, B.; Huffenberger, K.; O'Dwyer, I. J.; Gorski, K.; Yorke, H. W.; Zmuidzinas, J.; Paine, C.; hide

    2007-01-01

    We present a design for a cryogenically cooled large aperture telescope for far-infrared astronomy in the wavelength range 30 micrometers to 300 micrometers. The Cryogenic Aperture Large Infrared Space Telescope Observatory, or CALISTO, is based on an off-axis Gregorian telescope having a 4 m by 6 m primary reflector. This can be launched using an Atlas V 511, with the only optical deployment required being a simple hinged rotation of the secondary reflector. The off-axis design, which includes a cold stop, offers exceptionally good performance in terms of high efficiency and minimum coupling of radiation incident from angles far off the direction of maximum response. This means that strong astronomical sources, such as the Milky Way and zodiacal dust in the plane of the solar system, add very little to the background. The entire optical system is cooled to 4 K to make its emission less than even this low level of astronomical emission. Assuming that detector technology can be improved to the point where detector noise is less than that of the astronomical background, we anticipate unprecedented low values of system noise equivalent power, in the vicinity of 10(exp -19) WHz(exp -0.5), through CALISTO's operating range. This will enable a variety of new astronomical investigations ranging from studies of objects in the outer solar system to tracing the evolution of galaxies in the universe throughout cosmic time.

  10. Experimental Study on Durability Improvement of Fly Ash Concrete with Durability Improving Admixture

    PubMed Central

    Quan, Hong-zhu; Kasami, Hideo

    2014-01-01

    In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete, the compressive strength of fly ash concrete can be improved by 10%–20%, and the drying shrinkage is reduced by 60%. Carbonation resistance of concrete is roughly proportional to water-cement ratio regardless of water-binder ratio and fly ash replacement ratio. For the specimens cured in air for 2 weeks, the freezing-thawing resistance is improved. In addition, by making use of durability improving admixture, it is easier to control the air content and make fly ash concrete into nonair-entraining one. The quality of fly ash concrete is thereby optimized. PMID:25013870

  11. Experimental study on durability improvement of fly ash concrete with durability improving admixture.

    PubMed

    Quan, Hong-zhu; Kasami, Hideo

    2014-01-01

    In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete, the compressive strength of fly ash concrete can be improved by 10%-20%, and the drying shrinkage is reduced by 60%. Carbonation resistance of concrete is roughly proportional to water-cement ratio regardless of water-binder ratio and fly ash replacement ratio. For the specimens cured in air for 2 weeks, the freezing-thawing resistance is improved. In addition, by making use of durability improving admixture, it is easier to control the air content and make fly ash concrete into nonair-entraining one. The quality of fly ash concrete is thereby optimized.

  12. How an educational improvement project improved the summative evaluation of medical students.

    PubMed

    Hoffman, K G; Brown, R Margaret A; Gay, J W; Headrick, L A

    2009-08-01

    At the University of Missouri-Columbia School of Medicine (USA) "commitment to improving quality and safety in healthcare" is one of eight key characteristics set as goals for our graduates. As educators, commitment to continuous improvement in the educational experience has been modelled through improvement of the Medical Student Performance Evaluation (MSPE) letter (formerly the Dean's letter). This educational improvement project decreased waste, increased collaboration and developed locally useful knowledge. By applying continuous improvement principles to the construction of the MSPE the overall efficiency of the process could be enhanced, and the MSPE committee was able to spend less cognitive energy on structure and format and focus more on the content of the letters. Four MSPE cycles have been completed using a new Web-based system; after each cycle, additional enhancements were identified and implemented. This work adds to the literature, as it describes the application of continuous improvement principles to an educational system.

  13. Embarking on performance improvement.

    PubMed

    Brown, Bobbi; Falk, Leslie Hough

    2014-06-01

    Healthcare organizations should approach performance improvement as a program, not a project. The program should be led by a guidance team that identifies goals, prioritizes work, and removes barriers to enable clinical improvement teams and work groups to realize performance improvements. A healthcare enterprise data warehouse can provide the initial foundation for the program analytics. Evidence-based best practices can help achieve improved outcomes and reduced costs.

  14. Practice-based learning and improvement: a curriculum in continuous quality improvement for surgery residents.

    PubMed

    Canal, David F; Torbeck, Laura; Djuricich, Alexander M

    2007-05-01

    Surgery residents can learn continuous quality improvement (CQI) principles within a structured curriculum and propose quality improvement projects. Curriculum within a surgical residency program. A university surgical residency program with multiple hospital training sites. Fifteen surgical residents during the dedicated research year. A curriculum in CQI that focuses on devising a quality improvement project. Resident self-reported attitudes about quality improvement and implementation of resident-initiated quality improvement projects. Resident survey data demonstrated an improvement in knowledge, self-efficacy, and experiences within CQI. Fifteen individual residents, within smaller teams, created 4 quality improvement projects worthy of implementation. A structured CQI curriculum can be successfully integrated into a general surgery residency program. Residents can learn the skill of constructing CQI project ideas within the framework of the plan-do-study-act cycle. Residents are eager to make improvements in their local system of residency. By giving them the tools to critically investigate systems improvement and a much needed ear to hear their concerns and suggestions for improvement, we found ways to potentially enhance patient care and developed ideas to improve the education of future surgeons. In doing so, we provided the residents with "buy-in" into their residency program, while addressing the competency of practice-based learning and improvement required by the Accreditation Council for Graduate Medical Education for resident education.

  15. Link between interplanetary & cometary dust: Polarimetric observations and space studies with Rosetta & Eye-Sat

    NASA Astrophysics Data System (ADS)

    Levasseur-Regourd, Anny-Chantal; Gaboriaud, Alain; Buil, Christian; Ressouche, Antoine; Lasue, J.; Palun, Adrien; Apper, Fabien; Elmaleh, Marc

    Intensity and linear polarization observations of the solar light scattered by interplanetary dust, the so-called zodiacal light, provide information on properties of the dust particles, such as their spatial density, local changes, morphology and albedo. Earth-based polarimetric observations, with a resolution of 5° or more, have been used to derive the polarization phase curve of interplanetary dust particles and to establish that the polarization at 90° phase angle increases with increasing solar distance, at least up to 1.5 au in the ecliptic, while the albedo decreases [1, 2]. Analysis of such studies will be revisited. Numerical simulations of the polarimetric behavior of interplanetary dust particles strongly suggest that, in the inner solar system, interplanetary dust particles consist of absorbing (e.g., organic compounds) and less absorbing (e.g., silicates) materials, that radial changes originate in a decrease of organics with decreasing solar distance (probably due to alteration processes), and that a significant fraction of the interplanetary dust is of cometary origin, in agreement with dynamical studies [3, 4]. The polarimetric behaviors of interplanetary dust and cometary dust particles seem to present striking similarities. The properties of cometary dust particles, as derived from remote polarimetric observations of comets including 67P/Churyumov-Gerasimenko, the target of the Rosetta rendezvous mission, at various wavelengths, will be summarized [5, 6]. The ground truth expected from Rosetta dust experiments, i.e., MIDAS, COSIMA, GIADA, about dust particles’ morphology, composition, and evolution (with distance to the nucleus before Philae release and with distance to the Sun before and after perihelion passage) over the year and a half of nominal mission, will be discussed. Finally, the Eye-Sat nanosatellite will be presented. This triple cubesat, developed by students from engineering schools working as interns at CNES, is to be launched

  16. Improving Efficiency While Improving Patient Care in a Student-Run Free Clinic.

    PubMed

    Lee, Jason S; Combs, Kristen; Pasarica, Magdalena

    2017-01-01

    Student-run free clinics (SRFCs) have the capacity to decrease health care inequity in underserved populations. These facilities can benefit from improved patient experience and outcomes. We implemented a series of quality improvement interventions with the objectives to decrease patient wait times and to increase the variety of services provided. A needs assessment was performed. Problems related to time management, communication between staff and providers, clinic resources, and methods for assessing clinic performance were identified as targets to reduce wait times and improve the variety of services provided. Seventeen interventions were designed and implemented over a 2-month period. The interventions resulted in improved efficiency for clinic operations and reduced patient wait times. The number of specialty providers, patient visits for specialty care, lifestyle education visits for disease prevention and treatment, free medications, and free laboratory investigations increased to achieve the goal of improving the availability and the variety of services provided. We demonstrated that it is feasible to implement successful quality improvement interventions in SRFCs to decrease patient wait times and to increase the variety of services provided. We believe that the changes we implemented can serve as a model for other SRFCs to improve their performance. © Copyright 2017 by the American Board of Family Medicine.

  17. Continuous Improvement in Education. Advancing Teaching--Improving Learning. White Paper

    ERIC Educational Resources Information Center

    Park, Sandra; Hironaka, Stephanie; Carver, Penny; Nordstrum, Lee

    2013-01-01

    In recent years, "continuous improvement" has become a popular catchphrase in the field of education. However, while continuous improvement has become commonplace and well-documented in other industries, such as healthcare and manufacturing, little is known about how this work has manifested itself in education. This white paper attempts…

  18. Improving engineering effectiveness

    NASA Technical Reports Server (NTRS)

    Fiero, J. D.

    1985-01-01

    Methodologies to improve engineering productivity were investigated. The rocky road to improving engineering effectiveness is reviewed utilizing a specific semiconductor engineering organization as a case study. The organization had a performance problem regarding new product introductions. With the help of this consultant as a change agent the engineering team used a systems approach to through variables that were effecting their output significantly. Critical factors for improving this engineering organization's effectiveness and the roles/responsibilities of management, the individual engineers and the internal consultant are discussed.

  19. MSTor version 2013: A new version of the computer code for the multi-structural torsional anharmonicity, now with a coupled torsional potential

    NASA Astrophysics Data System (ADS)

    Zheng, Jingjing; Meana-Pañeda, Rubén; Truhlar, Donald G.

    2013-08-01

    We present an improved version of the MSTor program package, which calculates partition functions and thermodynamic functions of complex molecules involving multiple torsions; the method is based on either a coupled torsional potential or an uncoupled torsional potential. The program can also carry out calculations in the multiple-structure local harmonic approximation. The program package also includes seven utility codes that can be used as stand-alone programs to calculate reduced moment of inertia matrices by the method of Kilpatrick and Pitzer, to generate conformational structures, to calculate, either analytically or by Monte Carlo sampling, volumes for torsional subdomains defined by Voronoi tessellation of the conformational subspace, to generate template input files for the MSTor calculation and Voronoi calculation, and to calculate one-dimensional torsional partition functions using the torsional eigenvalue summation method. Restrictions: There is no limit on the number of torsions that can be included in either the Voronoi calculation or the full MS-T calculation. In practice, the range of problems that can be addressed with the present method consists of all multitorsional problems for which one can afford to calculate all the conformational structures and their frequencies. Unusual features: The method can be applied to transition states as well as stable molecules. The program package also includes the hull program for the calculation of Voronoi volumes, the symmetry program for determining point group symmetry of a molecule, and seven utility codes that can be used as stand-alone programs to calculate reduced moment-of-inertia matrices by the method of Kilpatrick and Pitzer, to generate conformational structures, to calculate, either analytically or by Monte Carlo sampling, volumes of the torsional subdomains defined by Voronoi tessellation of the conformational subspace, to generate template input files, and to calculate one-dimensional torsional

  20. Using Quality Improvement to Improve Internal and External Coordination and Referrals.

    PubMed

    Cain, Katherine L; Collins, Ragan P

    As part of accreditation, Public Health Accreditation Board site visitors recommended that the New Orleans Health Department strengthen its quality improvement program. With support from the Public Health Accreditation Board, the New Orleans Health Department subsequently embarked on a data-driven planning process through which it prioritized quality improvement projects for 2016. One of these projects aimed to improve referrals to New Orleans Health Department's direct services programs from local clinics and hospitals to better provide our most vulnerable residents with a continuum of care. After completing a cause-and-effect analysis, we implemented a solution involving increased outreach to health care institutions and saw annual participation increase in 3 out of 4 of our programs. We leveraged this work to successfully apply for funding to create a centralized referral system, which will facilitate partnerships among local health and human service agencies and improve access to services. This is one example of how accreditation has benefited our health department and our community. We have found that the accreditation process promotes a culture of quality and helps health departments identify and address areas for improvement.