Sample records for versigonalia ruficauda walker

  1. Compliant Walker

    NASA Technical Reports Server (NTRS)

    Kerley, James J.; Eklund, Wayne; Crane, Alan

    1992-01-01

    Walker supports person with limited use of legs and back. Enables person to stand upright, move with minimum load, and rest at will taking weight off legs. Consists of wheeled frame with body harness connected compliantly to side structures. Harness supports wearer upright when wearer relaxes and takes weight off lower extremities. Assumes partial to full body weight at user's discretion.

  2. Compliant walker

    NASA Technical Reports Server (NTRS)

    Kerley, James J. (inventor); Eklund, Wayne D. (inventor); Crane, J. Allen (inventor)

    1992-01-01

    A compliant walker is provided for humans having limited use of their legs and lower back. It includes an upright wheel frame which at least partially surrounds an upright user wearing a partial body harness. It is attached to the frame by means of cable compliant apparatus consisting of sets of cable segments and angle bracket members connected between opposite side members of the frame and adjacent side portions of the harness. Novelty is believed to exist in the combination of a wheeled frame including a side support structure, a body harness, and compliance means connecting the body harness to the side support structure for flexibility holding and supporting a person in a substantially upright position when the user sags in the frame when taking weight off the lower extremities.

  3. Dissimilar bouncy walkers.

    PubMed

    Lomholt, Michael A; Lizana, Ludvig; Ambjörnsson, Tobias

    2011-01-28

    We consider the dynamics of a one-dimensional system consisting of dissimilar hardcore interacting (bouncy) random walkers. The walkers' (diffusing particles') friction constants ?(n), where n labels different bouncy walkers, are drawn from a distribution ?(?(n)). We provide an approximate analytic solution to this recent single-file problem by combining harmonization and effective medium techniques. Two classes of systems are identified: when ?(?(n)) is heavy-tailed, ?(?(n))??(n) (-1-?)?(0

  4. Dissimilar bouncy walkers

    NASA Astrophysics Data System (ADS)

    Lomholt, Michael A.; Lizana, Ludvig; Ambjörnsson, Tobias

    2011-01-01

    We consider the dynamics of a one-dimensional system consisting of dissimilar hardcore interacting (bouncy) random walkers. The walkers' (diffusing particles') friction constants ? _n, where n labels different bouncy walkers, are drawn from a distribution \\varrho (? _n). We provide an approximate analytic solution to this recent single-file problem by combining harmonization and effective medium techniques. Two classes of systems are identified: when \\varrho (? _n) is heavy-tailed, \\varrho (? _n)˜eq ? _n^{-1-? } (0

  5. Joseph (Joe) A. Walker

    NASA Technical Reports Server (NTRS)

    1956-01-01

    In March 1945 Joseph A. Walker joined the National Advisory Committee for Aeronautics' Aircraft Engine Research Laboratory, Cleveland, Ohio, (later NASA's Lewis Research Center, now the Glenn Research Center) as a physicist. He transferred to the NACA High-Speed Flight Research Station, Edwards, California in 1951, as a research pilot. For the next fifteen years Walker served as a pilot at the Edwards flight research facility (today known as NASA's Dryden Flight Research Center) on such projects as the Bell X-1#2 (2 flights, first on August 27, 1951), Bell X-1A (1 flight on July 20, 1955), X-1E (21 flights, first on December 12, 1955), Douglas D-558-I #3 Skystreak (14 flights, first on June 29, 1951), Douglas D-558-II #2 Skyrocket (3 flights, first on April 29, 1955), Douglas D-558-II #3 Skyrocket (2 flights, first on May 7, 1954). On the Douglas X-3, Joe was project pilot and made all 20 flights, the first on August 1, 1954. Joe considered this aircraft the 'worst' plane he ever flew. He flew the Northrup X-4 (2 flights, first on October 18, 1951), Bell X-5 (78 flights, first on January 9, 1952). He also flew programs involving the F-100, F-101, F-102, F-104 and the B-47. Walker made the first NASA flight on the North American X-15 on March 25, 1960. His 25th and final X-15 flight on August 22, 1963, reached 354,200 feet, an unofficial record altitude of almost 67 miles. On October 30, 1964, Walker took the first Bell Lunar Landing Research Vehicle (LLRV) on its maiden flight, reaching a peak altitude of 10 feet and a free flight time of just under one minute. Two LLRV's and three Lunar Landing Training Vehicles developed from them were used to develop piloting and operational techniques for lunar landings. In November, he left the program after 35 flights on the first LLRV. Walker flew chase flights as well as research flights. On June 8, 1966 he was flying chase in NASA's F-104N for the Air Force's experimental bomber, North American XB-70A, when he was fatally injured in a mid-air collision between the planes. Joe graduated from Washington and Jefferson College in 1942, with a Bachelors degree in Physics. He enrolled in the civilian pilot training program in 1941 and, after graduation from college, entered the Army Air Forces. During World War II he flew P-38 fighters and F-5A photo reconnaissance for the Air Force, earning the Distinguished Flying Cross and the Air Medal with Seven Oak Clusters. Walker was a charter member of the Society of Experimental Test Pilots and one of the first to be designated a Fellow. He was honored with the Robert J. Collier Trophy, the Harmon International Trophy for Aviators, the Iven C. Kincheloe Award and the Octave Chanute Award, all in 1961. He received an honorary Doctor of Aeronautical Sciences degree from his alma mater in June of 1961 and was named Pilot of the Year in 1963 by the National Pilots Association. Joseph Albert Walker was born February 20, 1921, in Washington, Pennsylvania; he died on June 8, 1966 at Edwards, California.

  6. 21 CFR 890.3825 - Mechanical walker.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Mechanical walker. 890.3825 Section 890.3825...Medicine Prosthetic Devices § 890.3825 Mechanical walker. (a) Identification. A mechanical walker is a four-legged device...

  7. November 2012 ROBERT T. WALKER

    E-print Network

    Walker, Robert T.

    of American Geographers 101(4): 929-938. Leite, F. L., Caldas, M. M., Simmons, C., Perz, S. G., Aldrich, S Refereed Journal Articles Walker, R., Arima, E., Messina, J., Soares-Filho, B., Perz, S., Sales, M, P., Myers, R. J., Swinton, S. M., and Walker. R. 2012. Exchange rates, soybean supply response

  8. Light-Fueled Microscopic Walkers.

    PubMed

    Zeng, Hao; Wasylczyk, Piotr; Parmeggiani, Camilla; Martella, Daniele; Burresi, Matteo; Wiersma, Diederik Sybolt

    2015-07-01

    The first microscopic artificial walker equipped with liquid-crystalline elastomer muscle is reported. The walker is fabricated by direct laser writing, is smaller than any known living terrestrial creatures, and is capable of several autonomous locomotions on different surfaces. PMID:26033690

  9. Intelligently Controllable Walker with Magnetorheological Fluid Brake

    NASA Astrophysics Data System (ADS)

    Kikuchi, Takehito; Tanida, Sosuke; Tanaka, Toshimasa; Kobayashi, Keigo; Mitobe, Kazuhisa

    Caster walkers are supporting frames with casters and wheels. These tools are regularly utilized as life support tools or walking rehabilitation tools in hospitals, nursing homes and individual residences. Users of the walkers can easily move it thanks to its wheels and casters. However falling accidents often happen when it moves without users. The falling accident is very serious problem and one of leading causes of secondary injuries. In the other case, it is hard to move to desired directions if users have imbalance in their motor functions or sensory functions, e.g., hemiplegic patients. To improve safeness and operability of the walkers, we installed compact MR fluid brakes on the wheels and controlled walking speed and direction of the walker. We named this intelligently controllable walker, “i-Walker” and discussed on the control methods and experimental results in this paper. Preliminary trials for direction control of the first-generation of the i-Walker (i-Walker1) are presented. On the basis of the results, we improved the control method and hardware of the i-Walker1, and developed the second-generation (i-Walker2). System description and experimental results of the i-Walker2 are also described. The i-Walker2 has better operability and lower energy consumption than that of the i-Walker1. The line-tracing controller of the i-Walker2 well controls human motions during walking experiments on the target straight line.

  10. WebWalker: Issue 3

    NSDL National Science Digital Library

    1999-01-01

    WebWalker "is a newsletter about the Walker Art Center Websites and digital culture on the net." The third issue features Airworld, net art by Jennifer and Kevin McCoy, and Mark Amerika's PHON:E:ME. Airworld is designed to make readers question what they expect from a Website. At first, the site looks slick and commercial, but then one starts noticing oddities, such as a repeated slide graphic that will not fill in, linked to text does not quite match, and blurry images, all of which raise questions about what kind of site this actually is. PHON:E:ME was launched in June, 1999, and WebWalker coverage includes links to the work itself, a collection of essays, interviews with the artists, and viewer comments.

  11. Richard C. Ferrero William A. Walker

    E-print Network

    I., 1985; Perryman and Lynn, 1993; Heyning and Perrin, 1994; Walker and Cowan1; Walker et a1.2). Two, 1969; Evans, 1975). Heyning and Perrin (1994) de- scribed two species of Delphinus from the eastern

  12. Obituary: Robert Mowbray Walker, 1929-2004

    Microsoft Academic Search

    Neil T. Schoenherr

    2004-01-01

    Robert M. Walker, PhD, Professor of Physics in Arts & Sciences and a faculty fellow of the McDonnell Center for the Space Sciences, died of stomach cancer Thursday, 12 February 2004, in Brussels, Belgium. He was 75. Walker worked on the frontiers of space research for more than four decades. Robert Walker was born in Philadelphia on 6 February 1929.

  13. Thad G. Walker Research Highlights

    E-print Network

    Yavuz, Deniz

    , Molecular, and Optical Physics 43 Archival journals: Physical Review, Journal of the Optical Society. Walker Publications in Refereed Journals 27 Physical Review Letters, Nature Physics 2 Reviews of Modern of America, Journal of Ap- plied Physics, Applied Optics, Journal of Chemical Physics 115. "Atomic Fock State

  14. Abstract models of molecular walkers

    NASA Astrophysics Data System (ADS)

    Semenov, Oleg

    Recent advances in single-molecule chemistry have led to designs for artificial multi-pedal walkers that follow tracks of chemicals. The walkers, called molecular spiders, consist of a rigid chemically inert body and several flexible enzymatic legs. The legs can reversibly bind to chemical substrates on a surface, and through their enzymatic action convert them to products. We study abstract models of molecular spiders to evaluate how efficiently they can perform two tasks: molecular transport of cargo over tracks and search for targets on finite surfaces. For the single-spider model our simulations show a transient behavior wherein certain spiders move superdiffusively over significant distances and times. This gives the spiders potential as a faster-than-diffusion transport mechanism. However, analysis shows that single-spider motion eventually decays into an ordinary diffusive motion, owing to the ever increasing size of the region of products. Inspired by cooperative behavior of natural molecular walkers, we propose a symmetric exclusion process (SEP) model for multiple walkers interacting as they move over a one-dimensional lattice. We show that when walkers are sequentially released from the origin, the collective effect is to prevent the leading walkers from moving too far backwards. Hence, there is an effective outward pressure on the leading walkers that keeps them moving superdiffusively for longer times. Despite this improvement the leading spider eventually slows down and moves diffusively, similarly to a single spider. The slowdown happens because all spiders behind the leading spiders never encounter substrates, and thus they are never biased. They cannot keep up with leading spiders, and cannot put enough pressure on them. Next, we investigate search properties of a single and multiple spiders moving over one- and two-dimensional surfaces with various absorbing and reflecting boundaries. For the single-spider model we evaluate by how much the slowdown on newly visited sites, owing to catalysis, can improve the mean first passage time of spiders and show that in one dimension, when both ends of the track are an absorbing boundary, the performance gain is lower than in two dimensions, when the absorbing boundary is a circle; this persists even when the absorbing boundary is a single site. Next, we study how multiple molecular spiders influence one another during the search. We show that when one spider reaches the trace of another spider it is more likely not to follow the trace and instead explore unvisited sites. This interaction between the spiders gives them an advantage over independent random walkers in a search for multiple targets. We also study how efficiently the spiders with various gaits are able to find specific targets. Spiders with gaits that allow more freedom of leg movement find their targets faster than spiders with more restrictive gaits. For every gait, there is an optimal detachment rate that minimizes the time to find all target sites.

  15. Hemispherical Scale (Saissetia coffeae (Walker))

    Microsoft Academic Search

    Donald Nafus

    emispherical or helmet scale (Saissetia coffeae (Walker) (Homoptera: Coccidae)) is a yellow-brown to dark brown scale found on leaves, on small twigs, shoots, and fruits. The scale is shaped like a half-sphere, being very dome-shaped with the base varying from circular to elongated. It is between 1.5 and 3 millimeters (mm) long when mature. Up to 600 eggs are laid

  16. Motion Control of Passive Intelligent Walker Using Servo Brakes

    Microsoft Academic Search

    Yasuhisa Hirata; Asami Hara; Kazuhiro Kosuge

    2007-01-01

    We propose a new intelligent walker based on passive robotics that assists the elderly, handicapped people, and the blind who have difficulty in walking. We developed a prototype of the robot technology walker (RT walker), a passive intelligent walker that uses servo brakes. The RT walker consists of a support frame, two casters, two wheels equipped with servo brakes, and

  17. Ankle Actuation for Limit Cycle Walkers

    Microsoft Academic Search

    Daan G. E. Hobbelen; Martijn Wisse

    2008-01-01

    Limit Cycle Walkers are bipeds that exhibit a stable cyclic gait without requiring local controllability at all times during gait. Well-known example are McGeer's “Passive Dynamic Walkers”, but the concept expands to actuated bipeds as involved in this study. Current state-of-the-art Limit Cycle Walkers excel in being very energy efficient, but their ability to handle disturbances (i.e. disturbance rejection) is

  18. 21 CFR 890.3825 - Mechanical walker.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3825 Mechanical walker. (a) Identification. A mechanical...

  19. 21 CFR 890.3825 - Mechanical walker.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3825 Mechanical walker. (a) Identification. A...

  20. 21 CFR 890.3825 - Mechanical walker.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3825 Mechanical walker. (a) Identification. A...

  1. 21 CFR 890.3825 - Mechanical walker.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3825 Mechanical walker. (a) Identification. A...

  2. 78 FR 48301 - Establishment of Class E Airspace; Walker, MN

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-08

    ...Establishment of Class E Airspace; Walker, MN AGENCY: Federal Aviation Administration...establishes Class E airspace at Walker, MN. Controlled airspace is necessary to accommodate...establish Class E airspace for the Walker, MN, area, creating controlled airspace...

  3. by John Walker The Hacker's Diet

    E-print Network

    Bernstein, Daniel

    by John Walker #12; The Hacker's Diet How to lose weight and hair through stress and poor nutrition Cyberspace and CA (Cellular Automata) Lab. The following are trademarks of John Walker: The Hacker's Diet #12; ii THE HACKER'S DIET 4 FOOD AND FEEDBACK 41 Measure the quantity 41 Determine the goal 42 Apply

  4. A Robotic Walker That Provides Guidance

    Microsoft Academic Search

    Aaron Morris; Raghavendra Donamukkala; Anuj Kapuria; Aaron Steinfeld; Judith T. Matthews; Jacqueline Dunbar-Jacob; Sebastian Thrun

    2002-01-01

    This paper describes a robotic walker designed as an assistive device for frail elderly people with cognitive impairment. Lo- comotion is most often the primary form of exercise for the elderly, and devices that provide mobility assistance are criti- cal for the health and well being of such individuals. Previous work on walkers focused primarily on safety but offered little

  5. ZERO DYNAMICS OF UNDERACTUATED PLANAR BIPED WALKERS

    E-print Network

    Grizzle, Jessy W.

    ZERO DYNAMICS OF UNDERACTUATED PLANAR BIPED WALKERS E.R. Westervelt 1 J.W. Grizzle 1 D.E. Koditschek 2 University of Michigan, Ann Arbor, MI, USA Abstract: The zero dynamics of a hybrid model of the zero dynamics correspond to asymptotically stabilizable orbits of the full hybrid model of the walker

  6. undergraduate programs walker college of business

    E-print Network

    Thaxton, Christopher S.

    in nine majors ­ Accounting; Computer Information Systems; Economics; Finance and Banking; Hospitality and Tourism Management; International Business; Management; Marketing; and Risk Management and Insurance-savvy and possess practical knowledge of all business disciplines. John A. Walker John Walker was a businessman

  7. Exploration and Trapping of Mortal Random Walkers

    NASA Astrophysics Data System (ADS)

    Yuste, S. B.; Abad, E.; Lindenberg, Katja

    2013-05-01

    Exploration and trapping properties of random walkers that may evanesce at any time as they walk have seen very little treatment in the literature, and yet a finite lifetime is a frequent occurrence, and its effects on a number of random walk properties may be profound. For instance, whereas the average number of distinct sites visited by an immortal walker grows with time without bound, that of a mortal walker may, depending on dimensionality and rate of evanescence, remain finite or keep growing with the passage of time. This number can in turn be used to calculate other classic quantities such as the survival probability of a target surrounded by diffusing traps. If the traps are immortal, the survival probability will vanish with increasing time. However, if the traps are evanescent, the target may be spared a certain death. We analytically calculate a number of basic and broadly used quantities for evanescent random walkers.

  8. Exploration and Trapping of Mortal Random Walkers

    E-print Network

    S. B. Yuste; E. Abad; Katja Lindenberg

    2013-06-18

    Exploration and trapping properties of random walkers that may evanesce at any time as they walk have seen very little treatment in the literature, and yet a finite lifetime is a frequent occurrence, and its effects on a number of random walk properties may be profound. For instance, whereas the average number of distinct sites visited by an immortal walker grows with time without bound, that of a mortal walker may, depending on dimensionality and rate of evanescence, remain finite or keep growing with the passage of time. This number can in turn be used to calculate other classic quantities such as the survival probability of a target surrounded by diffusing traps. If the traps are immortal, the survival probability will vanish with increasing time. However, if the traps are evanescent, the target may be spared a certain death. We analytically calculate a number of basic and broadly used quantities for evanescent random walkers.

  9. X-1A with pilot Joe Walker

    NASA Technical Reports Server (NTRS)

    1955-01-01

    Cowboy Joe (NACA High-Speed Flight Station test pilot Joseph Walker) and his steed (Bell Aircraft Corporation X-1A) A happy Joe was photographed in 1955 at Edwards, California. The X-1A was flown six times by Bell Aircraft Company pilot Jean 'Skip' Ziegler in 1953. Air Force test pilots Maj. Charles 'Chuck' Yeager and Maj. Arthur 'Kit' Murray made 18 flights between 21 November 1953 and 26 August 1954. The X-1A was then turned over to the NACA. Joe Walker piloted the first NACA flight on 20 July 1955. Walker attemped a second flight on 8 August 1955, but an explosion damaged the aircraft just before launch. Walker, unhurt, climbed back into the JTB-29A mothership, and the X-1A was jettisoned over the Edwards AFB bombing range.

  10. 78 FR 25234 - Proposed Establishment of Class E Airspace; Walker, MN

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-30

    ...Establishment of Class E Airspace; Walker, MN AGENCY: Federal Aviation Administration...to establish Class E airspace at Walker, MN. Controlled airspace is necessary to accommodate...procedures at Walker Municipal Airport, Walker, MN. Controlled airspace is needed for...

  11. STS-30 Commander Walker on forward flight deck

    NASA Technical Reports Server (NTRS)

    1989-01-01

    On Atlantis', Orbiter Vehicle (OV) 104's, forward flight deck between commanders and pilots seats, STS-30 Commander David M. Walker smiles while having his picture taken. Walker, wearing a mission polo shirt and light blue flight coverall pants, holds onto the commanders seat back. Forward flight control panels are visible above Walker's head and behind him.

  12. 75 FR 51178 - Safety Standard for Infant Walkers; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-19

    ...concerning warning statements on walkers with parking brakes. DATES: Effective on December...concerning a warning statement for walkers with parking brakes omitted a phrase indicating that...is only required for walkers that have parking brakes. The preamble to the final...

  13. Declarative Processing for Computer Games Walker White

    E-print Network

    Keinan, Alon

    Declarative Processing for Computer Games Walker White Cornell University wmwhite@cs.cornell.edu Alan Demers Cornell University ademers@cs.cornell.edu Abstract Most game developers think of databases of declarative processing. In this paper we demonstrate how declarative processing can be applied to computer

  14. Gender Recognition from Point-Light Walkers

    ERIC Educational Resources Information Center

    Pollick, Frank E.; Kay, Jim W.; Heim, Katrin; Stringer, Rebecca

    2005-01-01

    Point-light displays of human gait provide information sufficient to recognize the gender of a walker and are taken as evidence of the exquisite tuning of the visual system to biological motion. The authors revisit this topic with the goals of quantifying human efficiency at gender recognition. To achieve this, the authors first derive an ideal…

  15. Cosmological Models Generalising Robertson-Walker Models

    E-print Network

    Abdussattar

    2003-08-07

    Considering the physical 3-space t = constant of the spacetime metrics as spheroidal and pseudo spheroidal, cosmological models which are generalizations of Robertson-Walker models are obtained. Specific forms of these general models as solutions of Einstein's field equations are also discussed in the radiation- and the matter-dominated eras of the universe.

  16. Scaling Games to Epic Proportions Walker White

    E-print Network

    Keinan, Alon

    Scaling Games to Epic Proportions Walker White Cornell University Ithaca, NY 14853, USA wmwhite@cs.cornell.edu ABSTRACT We introduce scalability for computer games as the next frontier for techniques from data management. A very important aspect of computer games is the artificial intelligence (AI) of non

  17. A simple characterization of generalized Robertson-Walker spacetimes

    E-print Network

    Bang-Yen Chen

    2014-11-02

    A generalized Robertson-Walker spacetime is the warped product with base an open interval of the real line endowed with the opposite of its metric and base any Riemannian manifold. The family of generalized Robertson-Walker spacetimes widely extends the one of classical Robertson-Walker spacetimes. In this article we prove a very simple characterization of generalized Robertson-Walker spacetimes; namely, a Lorentzian manifold is a generalized Robertson-Walker spacetime if and only if it admits a timelike concircular vector field.

  18. Modern lacustrine stromatolites, Walker Lake, Nevada

    NASA Astrophysics Data System (ADS)

    Osborne, Robert H.; Licari, Gerald R.; Link, Martin H.

    1982-05-01

    The Walker River drainage basin occupies about 10,000 km 2 in western Nevada and parts of California and is essentially a closed hydrologic system which drains from the crest of the Sierra Nevada in California and terminates in Walker Lake, Nevada. Walker Lake trends north and is about 27.4 km long and 8 km wide with water depths exceeding 30.5 m. The lake is situated in an asymmetric basin with steep alluvial fans flanking the western shoreline (Wassuk Range) and more gentle but areally more extensive alluvial fans flanking the eastern shoreline (Gillis Range). Exposed lake terraces and the present shoreline of Walker Lake record a sequence of Pleistocene and Holocene stromatolitic and tufaceous carbonate deposits. Small generalized and columnar stromatolites, frequently encrusted on exposed coarse-grained clasts or bedrock, are present along parts of the nearshore margin of Walker Lake and at elevated lake stands. Columnar stromatolites as much as 4 cm high are subcylindrical to club shaped discrete, and laterally linked at the base with local branching. These digitate stromatolites start as wavy, generalized stromatolites which are vertically transitional to small, laterally linked cabbage heads with laminae which thicken over the crests. Although algal structures are not well preserved in the older stromatolites, recent precipitation of low magnesium calcite occurs as smooth encrustations and as tiny mounds which are consistently associated with a diverse, seasonally variable, green and blue-green algal community including Cladophora glomerata, Ulothrix (cf. aequalis), Gongrosira, Schizothrix, Amphithrix janthina, Calothrix, Homeothrix, Spirulina, Anabaena, Lyngbya, and Entophysalis. Cladophora glomerata and a species of Ulothrix, which are the two most abundant algae within the Walker Lake stromatolite community, are known to condition semi-alkaline lake water by the removal of CO 2 from bicarbonate during photosynthesis. Such conditioning results in the precipitation of calcium carbonate, which is trapped and bound by an understory of green and blue-green algae. The occurrence of stromatolites in highly siliciclastic lakes seems to be restricted to shoreline and nearshore environments, and can be used to locate ancient lake margins.

  19. Conformally Friedmann-Lemaitre-Robertson-Walker cosmologies

    E-print Network

    Visser, Matt

    2015-01-01

    In a universe where, according to the standard cosmological models, some 97% of the total mass-energy is still "missing in action" it behooves us to spend at least a little effort critically assessing and exploring radical alternatives. Among possible, (dare we say plausible), nonstandard but superficially viable models, those spacetimes conformal to the standard Friedmann-Lemaitre-Robertson-Walker class of cosmological models play a very special role --- these models have the unique and important property of permitting large non-perturbative geometric deviations from Friedmann-Lemaitre-Robertson-Walker cosmology without unacceptably distorting the cosmic microwave background. Performing a "cosmographic" analysis, (that is, temporarily setting aside the Einstein equations, since the question of whether or not the Einstein equations are valid on galactic and cosmological scales is essentially the same question as whether or not dark matter/dark energy actually exist), and using both supernova data and informat...

  20. Speed and Exercise Intensity of Recreational Walkers

    Microsoft Academic Search

    Elaine M. Murtagh; Colin A. G. Boreham; Marie H. Murphy

    2002-01-01

    Background. Brisk walking has been identified as an activity suited to meet American College of Sport Medicine\\/Centers for Disease Control and Prevention recommendations for moderate intensity exercise (55–69% HRmax, 40–59% VO2R). However, little is known about whether recreational walkers self-select a pace which elicits this intensity and how they interpret the term “brisk walking.”Methods. The walking speed of 82 adults

  1. Obituary: Robert Mowbray Walker, 1929-2004

    NASA Astrophysics Data System (ADS)

    Schoenherr, Neil T.

    2004-12-01

    Robert M. Walker, PhD, Professor of Physics in Arts & Sciences and a faculty fellow of the McDonnell Center for the Space Sciences, died of stomach cancer Thursday, 12 February 2004, in Brussels, Belgium. He was 75. Walker worked on the frontiers of space research for more than four decades. Robert Walker was born in Philadelphia on 6 February 1929. His mother was Dorothy Potter and he considered Roger Potter his father though he was not his biological father. His early years were spent in New York City and in upstate New York. He attended the Bronx High School of Science, earned his BS in physics from Union College and in 1954, he received his PhD in particle physics from Yale University. He subsequently joined the General Electric Laboratory in Schenectady, New York where he studied the radiation effects in solids. His work on defects in irradiated copper is still regarded as the definitive work on the topic. In the early 1960s, Walker's discovery of fossil nuclear particle tracks in minerals was instrumental to new developments in geo-chronology and cosmic ray physics. In particular, his discovery of tracks from nuclei heavier than iron opened a new frontier of cosmic ray physics. He subsequently pioneered the use of plastics to detect and count such nuclei in cosmic ray balloon flights. Beginning in 1966, when he moved to Washington University and became the first McDonnell Professor of Physics, his research interests turned more toward space physics. He was the inaugural director of the McDonnell Center, which was established in 1975 by a gift from aerospace pioneer James S. McDonnell. Walker was a member of the NASA committee that allocated samples of the first returned lunar materials, and his laboratory led the way in deciphering their record of lunar, solar system and galactic evolution. Together with Ghislaine Crozaz and other colleagues, Walker made path breaking laboratory studies of the first moon rocks revealing the history of solar radiation and cosmic rays within these samples. He and Dr. Crozaz were married in 1973. In the past two decades, he was a world leader of microanalytical studies of tiny grains preserved for eons in meteorites, culminating in their identification as stardust. More recent achievements include the design of micrometeorite capture cells that were flown aboard NASA's Long Duration Exposure Facility; verification of the extraterrestrial origin of dust particles collected in the upper atmosphere; and the successful search for interstellar grains in meteorites. "Bob was such a dominant force for excellence in our department and the University over so many years, it is hard to grasp that he is gone," said John W. Clark, PhD, chair of physics, the Wayman Crow Professor and a faculty fellow of the McDonnell Center. "His passion for life and science was an inspiration to us all, and his legacy will endure in the work of his many colleagues and the extended family of his former students." Walker led the McDonnell Center, which includes one of the world's largest research groups dedicated to the search for and investigation of extraterrestrial materials, until 1999. "Washington University would be a lesser institution without the contributions of Bob Walker," said William H. Danforth, chancellor emeritus and vice chairman of the Board of Trustees. "He gave us inspiration, enthusiasm, great science and visionary leadership. He built the strength of the McDonnell Center for the Space Sciences. He convinced others of the potential for the modern Department of Earth and Planetary Sciences. He had always the respect and affection of us all." The last two decades of Walker's career were driven by his remarkable vision and his excitement at the prospect of profound discovery. His recognition of the potential importance of the ion microprobe for making isotopic measurements on microscopic samples, and his acquisition in 1982 of a state-of-the-art instrument for the University, led directly to a series of spectacular results. Chief among these was the ident

  2. COPESTYLUM CIRCUMDATUM (WALKER) (DIPTERA: SYRPHIDAE). A REDESCRIPTION, WITH LECTOTYPE DESIGNATIONS AND NEW SYNONYM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Copestylum circumdatum (Walker) (Diptera: Syrphidae) is redescribed. Lectotypes are designated for two names and one new synonym is proposed (Volucella mus Williston 1888 = circumdatum Walker 1857)....

  3. A business plan for iXa walker

    E-print Network

    Morton, Stephen A

    2010-01-01

    A market study was performed to determine the feasibility of the iXa Walker. The walker industry is about to enter a large growth due to the entry of millions of baby boomers into the durable medical equipment market. Using ...

  4. Last Glacial Maximum's effect on the Walker circulation

    Microsoft Academic Search

    Colin Schultz

    2011-01-01

    Over the tropical Pacific Ocean the Walker circulation is an atmospheric flow pattern that runs parallel to the equator, with ascending motion over the western Pacific and a horizontal tropospheric return flow that carries air back to the east. Scientists predict that the Walker circulation will weaken with global warming through a mechanism known as the Held, Soden, and Vecchi

  5. The World Function in Robertson-Walker Spacetime

    E-print Network

    Mark D. Roberts

    1999-05-02

    A method for finding the world function of Robertson-Walker spacetimes is presented. It is applied to find the world function for the $k=0, \\ga=2$, solution. The close point approximation for the Robertson-Walker world function is calculated upto fourth order.

  6. Designing a new joint for the iXa walker

    E-print Network

    Grove, Garth S

    2010-01-01

    In the fall of 2009, the Purple team developed a walker which allows users to rise from a seated position by folding down to provide a set of handles which the user can push off of to aid in the standing process. The walker ...

  7. Actuating a Simple 3D Passive Dynamic Walker Russ Tedrake

    E-print Network

    Tedrake, Russ

    a small push sideways, the walker will rock onto a single stance leg, allowing the opposite leg to leaveActuating a Simple 3D Passive Dynamic Walker Russ Tedrake Computer Science and Artificial. Finally, we present an actuated version of the robot and some preliminary active control strategies

  8. Territory covered by N random walkers.

    PubMed

    Yuste, S B; Acedo, L

    1999-10-01

    The problem of evaluating the number of distinct sites S(N)(t) covered up to time t by N random walkers is revisited. For the nontrivial time regime and for N>1 we show how to get the asymptotic behavior of S(N)(t) and we calculate the main and first two corrective terms. The mth corrective term decays mildly as 1/ln(m) N. For d-dimensional (d=1,2,3) simple cubic lattices, the main term is the volume of the hypersphere of radius [(ln N(2))2Dt/d](1/2), D being the diffusion constant, and the corrective terms account for the roughening of the surface of the set of visited sites. PMID:11970257

  9. Experimental detection of domain wall propagation above the Walker field.

    PubMed

    Kondou, Kouta; Ohshima, Norikazu; Chiba, Daichi; Kasai, Shinya; Kobayashi, Kensuke; Ono, Teruo

    2012-01-18

    The domain wall (DW) velocity above the Walker field drops abruptly with increasing magnetic field, because of the so-called Walker breakdown, where the DW moves with a precessional mode. On applying the higher field, the DW velocity again starts to increase gradually. We report the DW propagation around this local minimum regime in detail, investigated through the time-resolved electrical detection technique, with a magnetic tunnel junction. Just above the Walker field, we succeeded in detecting the precessional motion of the DW in a real-time regime, while a different mode appeared around the local minimum of the DW velocity. PMID:22173581

  10. Department of Mechanical Engineering Spring 2013 Intelligent Walker for Retirees

    E-print Network

    Demirel, Melik C.

    For this project TPC Innovation and Design was interested in improving an existing assistive walker they had concept from each challenge into final prototype · Wrote Arduino control code for logic interface

  11. Pilot Joe Walker and the X-1A

    NASA Technical Reports Server (NTRS)

    1955-01-01

    Cowboy Joe (NACA High-Speed Flight Station test pilot Joseph Walker) and his steed (Bell Aircraft Corporation X-1A). A happy Joe was photographed in 1955 at Edwards, California. The X-1A was flown six times by Bell Aircraft Company pilot Jean 'Skip' Ziegler in 1953. Air Force test pilots Major Charles 'Chuck' Yeager and Major Arthur 'Kit' Murray made 18 flights between November 21, 1953 and August 26, 1954. The X-1A was then turned over to the NACA. Joe Walker piloted the first NACA flight on July 20, 1955. Walker attemped a second flight on August 8, 1955, but an explosion damaged the aircraft just before launch. Walker, unhurt, climbed back into the JTB-29A mothership, and the X-1A was jettisoned over the Edwards AFB bombing range.

  12. Codimension two marginally trapped submanifolds in Robertson-Walker spaces

    E-print Network

    Henri Anciaux; Nastassja Cipriani

    2015-01-20

    We give a local characterization of codimension two submanifolds which are marginally trapped in Robertson-Walker spaces, in terms of an algebraic equation to be satisfied by the height function. We prove the existence of a large number of local solutions. We refine the description in the case of curves with null acceleration in three-dimensional spaces Robertson-Walker spaces, and in the case of codimension two submanifolds whose second fundamental form is null

  13. Aggregation of activated platelets with Walker 256 carcinoma cells

    Microsoft Academic Search

    W. Paschen; H. Patscheke; P. Wörner

    1979-01-01

    Zusammenfassung Walker 256 Karzinomzellen bilden irreversible Aggregate mit Ratten-Thrombozyten, die durch ADP oder Serotonin aktiviert wurden. Serotonin induziert bei Thrombozyten die Formänderung, jedoch keine Aggregation. Der Aktivierungsgrad der Thrombozyten, der durch die Scheiben-Kugel-Transformation angezeigt wird, ist demnach für die Reaktion zwischen Thrombozyten und Walker-Zellen ausreichend. Dies wird durch Versuche mit sphäroiden gewaschenen Thrombozyten bestätigt: Diese Thrombozyten bilden ohne zusätzlichen Stimulus

  14. Design and control of JAIST active robotic walker

    Microsoft Academic Search

    Geunho Lee; Takanori Ohnuma; Nak Young Chong

    2010-01-01

    This paper presents the design and control of a novel assistive robotic walker that we call “JAIST active robotic walker (JARoW)”.\\u000a JARoW is developed to provide potential users with sufficient ambulatory capability in an efficient, cost-effective way. Specifically,\\u000a our focus is placed on how to allow easier maneuverability by creating a natural interface between the user and JARoW. For\\u000a the

  15. Test pilots 1952 - Walker, Butchart, and Jones

    NASA Technical Reports Server (NTRS)

    1952-01-01

    This photo shows test pilots, (Left-Right) Joseph A. Walker, Stanley P. Butchart and Walter P. Jones, standing in front of the Douglas D-558-II Skystreak, in 1952. These three test pilots at the National Advisory Committee for Aeronautics' High-Speed Flight Research Station probably were discussing their flights in the aircraft. Joe flew research flights on the D-558-I #3 (14 flights, first on June 29, 1951) investigating buffeting, tail loads, and longitudinal stability. He flew the D-558-II #2 (3 flights, first on April 29, 1955) and recorded data on lateral stability and control. He also made pilot check-out flights in the D-558-II #3 (2 flights, first on May 7, 1954). For fifteen years Walker served as a pilot at the Edwards flight research facility (today known as the National Aeronautics and Space Administration's Dryden Flight Research Center) on research flights as well as chase missions for other pilots on NASA and Air Force research programs. On June 8, 1966, he was flying chase in NASA's F-104N for the Air Force's experimental bomber, North American XB-70A, when he was fatally injured in a mid-air collision between the planes. Stan flew the D-558-I #3 (12 flights, first on October 19, 1951) to determine the dynamic longitudinal stability characteristics and investigations of the lateral stability and control. He made one flight in the D-558-II #3 on June 26, 1953, as a pilot check-out flight. Butchart retired from the NASA Dryden Flight Research Center at Edwards, California, on February 27, 1976, after a 25-year career in research aviation. Stan served as a research pilot, chief pilot, and director of flight operations. Walter P. Jones was a research pilot for NACA from the fall of 1950 to July 1952. He had been in the U.S. Air Force as a pilot before joining the Station. Jones flew the D-558-I #3 (5 flights, first on February 13, 1951) to study buffeting, tail loads and longitudinal stability. Jones made research flights on the D-558-II #3 ( 7 flights, first on July 20, 1951). These flights investigated pitch-up and evaluated outboard wing fences. Walt also made research flights in the Northrop X-4 (14 flights, first on March 26, 1952) and the Bell X-5 (8 flights, first on June 20, 1952). In July 1952, Walt left NACA's High-Speed Flight Research Station to join Northrop Corporation as a pilot. Returning from a test mission in a Northrop YF-89D Scorpion he was fatally injured on October 20, 1953, near Edwards Air Force Base.

  16. The Walker Lane Belt in northeastern California

    SciTech Connect

    Grose, T.L.T. (Colorado School of Mines, Golden, CO (United States). Dept. of Geology and Geological Engineering)

    1993-04-01

    The Walker Lane Belt (WLB) has been suspected to significantly project NW-ward into NE CA from the Pyramid Lake-Honey Lake area which has been generally regarded as its northwestern terminus. Within the WLB, most of the exposed rocks are Miocene to Late Quaternary (10--0.1 Ma) volcanics, mainly andesitic, but significantly rhyolitic and basaltic. The Hayden Hill Au mine within a Mid-Miocene NNW-SSE volcanotectonic depression and the Quaternary NE-SW Eagle lake volcanotectonic depression are confined within the WLB. Most of the faults are high-angle normal and right normal, W-dipping, NW- to N-trending, and locally left-stepping en echelon, and 2 to 18 km long. Dip slip varies from 10 to 200 m. Strike slip across the entire zone seems impossible to determine, but probably is less than 20 km since Mid-Miocene. Many faults localize volcanic vents, though most do not appear to. Tectonic tilt of beds within fault blocks is less than 10[degree]. Fault activity and volcanism both continued at a slow rate from Mid-Miocene to Late Quaternary. The WLB in NE CA is a transitional boundary between the Sierra Nevada-Cascade arc on the southwest and the Basin and Range-Modoc Plateau on the northeast.

  17. Conformally Friedmann–Lemaître–Robertson–Walker cosmologies

    NASA Astrophysics Data System (ADS)

    Visser, Matt

    2015-07-01

    In a Universe where, according to the standard cosmological models, some 97% of the total mass-energy is still ‘missing in action’, it behooves us to spend at least a little effort critically assessing and exploring radical alternatives. Among possible (dare we say plausible), nonstandard but superficially viable models, those spacetimes conformal to the standard Friedmann–Lemaître–Robertson–Walker (FLRW) class of cosmological models play a very special role—these models have the unique and important property of permitting large non-perturbative geometric deviations from FLRW cosmology without unacceptably distorting the cosmic microwave background. Performing a ‘cosmographic’ analysis (that is, temporarily setting aside the Einstein equations, since the question of whether or not the Einstein equations are valid on galactic and cosmological scales is essentially the same question as whether or not dark matter/dark energy actually exist), and using both supernova data and information about galactic structure, one can nevertheless place some quite significant observational constraints on any possible conformal mode—however, there is still an extremely rich range of phenomenological possibilities for both cosmologists and astrophysicists to explore.

  18. Superdiffusive transport by multivalent molecular walkers moving under load

    NASA Astrophysics Data System (ADS)

    Olah, Mark J.; Stefanovic, Darko

    2013-06-01

    We introduce a model for translational molecular motors to demonstrate that a multivalent catalytic walker with flexible, uncoordinated legs can transform the free energy of surface-bound substrate sites into mechanical work and undergo biased, superdiffusive motion, even in opposition to an external load force. The walker in the model lacks any inherent orientation of body or track, and its legs have no chemomechanical coupling other than the passive constraint imposed by their connection to a common body. Yet, under appropriate kinetic conditions, the walker's motion is biased in the direction of unvisited sites, which allows the walker to move nearly ballistically away from the origin as long as a local supply of unmodified substrate sites is available. The multivalent random walker model is mathematically formulated as a continuous-time Markov process and is studied numerically. We use Monte Carlo simulations to generate ensemble estimates of the mean squared displacement and mean work done for this nonergodic system. Our results show that a residence time bias between visited and unvisited sites leads to superdiffusive motion over significant times and distances. This mechanism can be used to adapt any enzyme-substrate system with appropriate kinetics for use as a functional chemical implementation of a molecular motor, without the need for structural anisotropy or conformationally mediated chemomechanical coordination.

  19. Dandy Walker Variant and Bipolar I Disorder with Graphomania

    PubMed Central

    Karaka? U?urlu, Görkem; Çakmak, Selcen

    2014-01-01

    Cerebellum is known to play an important role in coordination and motor functions. In some resent studies it is also considered to be involved in modulation of mood, cognition and psychiatric disorders. Dandy Walker Malformation is a congenital malformation that is characterized by hypoplasia or aplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle and enlargement of the posterior fossa. When the volume of posterior fossa is normal, the malformation is called Dandy Walker Variant. Case is a 32 year old male with a 12 year history of Bipolar I Disorder presented with manic and depresive symptoms, including dysphoric and depressive affect, anhedonia, suicidal thoughts and behaviours, thoughts of fear about future, overtalkativeness and graphomania, increased energy, irregular sleep, loss of appetite, increased immersion in projects, irritability, agressive behavior, impulsivity. Cranial Magnetic Resonance Imaging was compatible to the morphological features of Dandy Walker Variant. PMID:25110509

  20. [Congenital generalized lipodystrophy in a patient with Dandy Walker anomaly].

    PubMed

    Luna, Cecilia Inés; Fernández Cordero, Marisa; Escruela, Romina; Sierra, Valeria; Córdoba, Antonela; Goñi, Ignacio María; Berridi, Ricardo

    2014-10-01

    The objective of this study is to describe the unexpected association between the congenital generalized lipodystrophy (CGL) and Dandy Walker anomaly. We report the case of a 1-year-old infant who was hospitalized at her fourth month of life with Dandy Walker anomaly diagnosis and an increased social risk. During her hospitalization, she developed progressively: acromegaloid aspect, triangular fascia, hirsutism, lipoatrophy, muscle hypertrophy, clitoromegaly, abdominal distention, progressive hepatomegaly, and hypertriglyceridemia. This led to the clinical diagnosis of congenital generalized lipodystrophy. Importance should be given to the examination of clinical aspects as well as the interdisciplinary follow-up for proper detection of insulin resistance and diabetes, early puberty, cardiomyopathy, among others. In case of Dandy Walker anomaly, it should be checked the evolution to search intracranial hypertension signs. Due to its autosomal recessive nature, it is important to provide genetic counseling to the parents. PMID:25192534

  1. The dual-task methodology and assessing the attentional demands of ambulation with walkers 

    E-print Network

    Cowley, Tammara Kemp

    1994-01-01

    with the RT task. The findings of Experiment 1 indicate that walking, aided by either the standard or the rolling walker was highly attention demanding. In addition, ambulation assisted by a standard walker was shown to require relatively greater attention...

  2. Improved Rehabilitation Walker Miguel Alvarez, Jason Porter, Richard Rubel; Advisor: Dr. Donald Bloswick

    E-print Network

    Provancher, William

    Improved Rehabilitation Walker Miguel Alvarez, Jason Porter, Richard Rubel; Advisor: Dr. Donald Bloswick . Fully Assembled Improved Rehabilitation Walker Details: Figure 1 Frame (1) The frame with leg movement accelerates patient rehabilitation. Fiberglass C section along wth

  3. States of Low Energy on Robertson-Walker Spacetimes

    E-print Network

    Heiner Olbermann

    2007-04-30

    We construct a new class of physical states of the free Klein-Gordon field in Robertson-Walker spacetimes. This is done by minimizing the expectation value of smeared stress-energy. We get an explicit expression for the state depending on the smearing function. We call it a state of low energy. States of low energy are an improvement of the concept of adiabatic vacua on Robertson-Walker spacetimes. The latter are approximations of the former. It is shown that states of low energy are Hadamard states.

  4. The Role of Walkers’ Needs and Expectations in Supporting Maintenance of Attendance at Walking Groups: A Longitudinal Multi-Perspective Study of Walkers and Walk Group Leaders

    PubMed Central

    Kassavou, Aikaterini; Turner, Andrew; French, David P.

    2015-01-01

    Background There is good evidence that when people’s needs and expectations regarding behaviour change are met, they are satisfied with that change, and maintain those changes. Despite this, there is a dearth of research on needs and expectations of walkers when initially attending walking groups and whether and how these needs and expectations have been satisfied after a period of attendance. Equally, there is an absence of research on how people who lead these groups understand walkers’ needs and walk leaders’ actions to address them. The present study was aimed at addressing both of these gaps in the research. Methods Two preliminary thematic analyses were conducted on face-to-face interviews with (a) eight walkers when they joined walking groups, five of whom were interviewed three months later, and (b) eight walk leaders. A multi-perspective analysis building upon these preliminary analyses identified similarities and differences within the themes that emerged from the interviews with walkers and walk leaders. Results Walkers indicated that their main needs and expectations when joining walking groups were achieving long-term social and health benefits. At the follow up interviews, walkers indicated that satisfaction with meeting similar others within the groups was the main reason for continued attendance. Their main source of dissatisfaction was not feeling integrated in the existing walking groups. Walk leaders often acknowledged the same reasons for walkers joining and maintaining attendance at walking. However, they tended to attribute dissatisfaction and drop out to uncontrollable environmental factors and/or walkers’ personalities. Walk leaders reported a lack of efficacy to effectively address walkers’ needs. Conclusions Interventions to increase retention of walkers should train walk leaders with the skills to help them modify the underlying psychological factors affecting walkers’ maintenance at walking groups. This should result in greater retention of walkers in walking groups, thereby allowing walkers to receive the long-term social and health benefits of participation in these groups. PMID:25774527

  5. Exploration and Trapping of Mortal Random Walkers S. B. Yuste,1

    E-print Network

    Lindenberg, Katja

    Exploration and Trapping of Mortal Random Walkers S. B. Yuste,1 E. Abad,2 and Katja Lindenberg3 1 visited by an immortal walker grows with time without bound, that of a mortal walker may, depending deals with one class of such problems associated with the territory explored by mortal or evanescent

  6. The response of the Walker circulation to Last Glacial Maximum forcing: Implications for detection in proxies

    E-print Network

    . [1] The response of the Walker circulation to Last Glacial Maximum (LGM) forcing is analyzed using Walker circulation during the LGM do not simulate clear patterns of surface cooling, such as La Niñalike to detect actual LGM changes in the Pacific and Indian Walker circulations, respectively, and help

  7. Mitchell L. R. Walker II Georgia Institute of Technology

    E-print Network

    Walker, Mitchell

    .walker@ae.gatech.edu Professional Interests: Advanced spacecraft and aircraft propulsion, plasma physics and rarefied gas dynamics, Hall thruster clustering and facility effects, electric propulsion plume diagnostics Education: Ph of the High-Power Electric Propulsion Laboratory Electric propulsion engine development, engine

  8. Do mitochondria recombine in humans? Adam Eyre-Walker

    E-print Network

    Eyre-Walker, Adam

    Do mitochondria recombine in humans? Adam Eyre-Walker Centre for the Study of Evolution and School should review an area of research in which John Maynard Smith is very much involved, namely recombination been largely ignored by evolutionary biology; John Maynard Smith is one of those who have brought

  9. Some Issues in Creating `Invertebrate' Robots I.D. Walker

    E-print Network

    Some Issues in Creating `Invertebrate' Robots I.D. Walker Clemson University, Dept. Electrical issues involved in the design, analysis, and implementation of `invertebrate- like' robots. Using as case, in invertebrate structures such as those in `tongues, trunks, and tentacles', highly dextrous ma- nipulation can

  10. Larval description of Copitarsia incommoda (Walker) (Lepidoptera: Noctuidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The last-instar larva of Copitarsia incommoda (Walker) is described for the first time. Specimens in this study were reared from quinoa (Chenopodium quinoa Willd., Chenopodiaceae), Bolivia, La Paz, 4 km S Viacha, Quipaquipani, 3880 m. The larva of Copitarsia incommoda is compared with larvae of Copi...

  11. Aerial view, view north with Walkers Mill left of the ...

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

    Aerial view, view north with Walkers Mill left of the creek, Henry Clay village right of creek, Tyler-Mcconnell Bridge in middleground, and Hagley area beyond the bridge - Charles I. Du Pont House, 162 Main Street, Wilmington, New Castle County, DE

  12. 12. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard ...

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

    12. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard and Gill, Architects September 23, 1904 (Revised October 28, 1904) BLUEPRINT OF ORIGINAL DRAWING OF EAST ELEVATION From the Collection of the San Diego Historical Society - George W. Marston House, 3525 Seventh Avenue, San Diego, San Diego County, CA

  13. 9. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard ...

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

    9. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard and Gill, Architects September 21, 1904 (Revised October 21, 1904) BLUEPRINT OF ORIGINAL DRAWING OF SOUTH ELEVATION From the Collection of the San Diego Historical Society - George W. Marston House, 3525 Seventh Avenue, San Diego, San Diego County, CA

  14. 10. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard ...

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

    10. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard and Gill, Architects September 21, 1904 (Revised October 28, 1904) BLUEPRINT OF ORIGINAL DRAWING OF WEST ELEVATION From the Collection of the San Diego Historical Society - George W. Marston House, 3525 Seventh Avenue, San Diego, San Diego County, CA

  15. 11. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard ...

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

    11. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard and Gill, Architects October 28, 1904 BLUEPRINT OF ORIGINAL DRAWING OF NORTH ELEVATION From the Collection of the San Diego Historical Society - George W. Marston House, 3525 Seventh Avenue, San Diego, San Diego County, CA

  16. General Transformation Formulas for Fermi-Walker Coordinates

    E-print Network

    David Klein; Peter Collas

    2008-06-27

    We calculate the transformation and inverse transformation, in the form of Taylor expansions, from arbitrary coordinates to Fermi-Walker coordinates in tubular neighborhoods of arbitrary timelike paths for general spacetimes. Explicit formulas for coefficients and the Jacobian matrix are given.

  17. John F. Walker, US Geological Survey Friday, November 18 , 2011

    E-print Network

    John F. Walker, US Geological Survey Friday, November 18 , 2011 3:30 p.m. RAWLS Hall, room 1011 P U T E R Estimating climate change impacts on streamflow in the Lake Michigan basin using the USGS PRMS watershed model The U.S. Geological Survey (USGS) entered into an interagency agreement with the U

  18. How clonal are human mitochondria? Adam Eyre-Walker*

    E-print Network

    Eyre-Walker, Adam

    How clonal are human mitochondria? Adam Eyre-Walker* , Noel H. Smith and John Maynard Smith Centre composition bias. There must either be `hypervariable' sites or recombination between mitochondria. We present that recombination has occurred between mitochondrial lineages in humans. Keywords: mitochondria; recombination

  19. What is "Next" in Event Processing? Walker White, Mirek Riedewald,

    E-print Network

    Keinan, Alon

    What is "Next" in Event Processing? Walker White, Mirek Riedewald, Johannes Gehrke, Alan Demers processing systems have wide applications ranging from managing events from RFID readers to monitoring RSS: how events are sequenced (what is the "next" event), and how the time stamp of an event is represented

  20. Developmental outcomes of Down syndrome and Dandy-Walker malformation

    PubMed Central

    Love, Kaitlin; Huddleston, Lillie; Olney, Pat; Wrubel, David; Visootsak, Jeannie

    2012-01-01

    Dandy-Walker syndrome (DWS), or Dandy-Walker complex, is a congenital brain malformation of the posterior fossa, typically resulting in developmental delay and cognitive disability. The co-occurrence of Down syndrome (DS) and DWS is relatively uncommon; thus, its impact on developmental outcomes has not been fully elucidated. Herein, we report a case of a 37-month-old child with DS and DWS, who is functioning at the following age-equivalent: gross motor at a 9-mo level, fine motor 6 mo, expressive language 14 mo, receptive language 9 mo. As such, it is important to determine how the DWS influences developmental outcomes, and appreciate the importance of early interventional therapy. PMID:22866020

  1. 1. EXTERIOR VIEW OF ELM CITY PLANT (A. FRANCIS WALKER, ...

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

    1. EXTERIOR VIEW OF ELM CITY PLANT (A. FRANCIS WALKER, 1905-07) FROM SECOND AVENUE ON OPPOSITE SIDE OF ENTRANCE. THIS STRUCTURE WAS ORIGINALLY BUILT AS THE ELM CITY COTTON MILL OF CALLAWAY MILLS. NOTE RESERVOIR IN FOREGROUND. THIS PHOTOGRAPH IS THE LEFT SIDE OF A PANORAMA VIEW THAT INCLUDES HAER Nos. GA-128-2 AND GA-128-3. - Elm City Cotton Mill, 1000 Elm Street, La Grange, Troup County, GA

  2. Beyond the Friedmann-Lemaitre-Robertson-Walker Big Bang singularity

    E-print Network

    Ovidiu-Cristinel Stoica

    2012-08-07

    Einstein's equation, in its standard form, breaks down at the Big Bang singularity. A new version, equivalent to Einstein's whenever the latter is defined, but applicable in wider situations, is proposed. The new equation remains smooth at the Big Bang singularity of the Friedmann-Lemaitre-Robertson-Walker model. It is a tensor equation defined in terms of the Ricci part of the Riemann curvature. It is obtained by taking the Kulkarni-Nomizu product between Einstein's equation and the metric tensor.

  3. Friedman—Robertson—Walker Models with Late-Time Acceleration

    NASA Astrophysics Data System (ADS)

    Abdussattar; Prajapati, S. R.

    2011-02-01

    In order to account for the observed cosmic acceleration, a modification of the ansatz for the variation of density in Friedman—Robertson—Walker (FRW) FRW models given by Islam is proposed. The modified ansatz leads to an equation of state which corresponds to that of a variable Chaplygin gas, which in the course of evolution reduces to that of a modified generalized Chaplygin gas (MGCG) and a Chaplygin gas (CG), exhibiting late-time acceleration.

  4. Gonadoblastoid Testicular Dysplasia in Walker-Warburg Syndrome

    Microsoft Academic Search

    Noelyn A. Hung; Meredith M. Silver; David Chitayat; John Provias; A. Toi; Venita Jay; Laurence E. Becker

    1998-01-01

    Two male fetuses (18 and 22 weeks gestation) and a 3-month-old male infant (full sibling of the younger fetus) who were diagnosed\\u000a with Walker-Warburg syndrome (WWS) on the basis of neuropathologic autopsy findings in brain, eyes, and muscle also had micro-orchia\\u000a and, microscopically, diffuse gonadoblastoid dysplasia in the testes. Both fetuses also had a miniature left ureter and cystic\\u000a dysplastic

  5. Particle filter based feedback control of JAIST Active Robotic Walker

    Microsoft Academic Search

    Takanori Ohnuma; Geunho Lee; Nak Young Chong

    2011-01-01

    We present a new control scheme of JAIST Ac- tive Robotic Walker (JARoW) developed to provide potential users such as the elderly with sufficient ambulatory capability. Toward its practical use, we tackle JARoW's easy and reliable maneuverability by creating a natural user interface between a user and JARoW. Specifically, our focus is placed on how to realize the natural and

  6. Maternal use of baby walkers with young children: recent trends and possible alternatives

    PubMed Central

    DiLillo, D; Damashek, A; Peterson, L

    2001-01-01

    Objectives—To examine recent trends in baby walker and exersaucer use, and to assess maternal motivations for choosing to use or not use these devices with children. Setting—Small, Midwestern city in the United States. Methods—Retrospective telephone survey with a sample of 329 mothers who provided information about their use of walkers and exersaucers with 463 children born in Columbia, Missouri between January 1994 and April 1999. Results—Baby walker use in the sample declined fairly steadily from 1994 to 1999, whereas exersaucer use increased during the same period. Altogether 88% of mothers were aware of the injury risks associated with walkers, and this knowledge was the most commonly reported reason for abstaining from walker use. Remarkably, 38% of participants with knowledge of walker risks nevertheless used these devices. Participants reported many reasons for using walkers and exersaucers, including child entertainment, perceived developmental benefit, easy availability, and improved safety of exersaucers. Conclusions—Public knowledge of the hazards of walkers seems to be high, and this awareness is a likely factor in many caregivers' decisions not to use them. Future interventions should focus particular attention on those caregivers who continue to use walkers despite knowledge of the associated risks. In addition to persuasive interventions, alternatives to walkers should be encouraged. Exersaucers represent one viable alternative, and should be promoted as such by the media, pediatricians, and other child care professionals. PMID:11565989

  7. Uranium transport in the Walker River Basin, California and Nevada

    USGS Publications Warehouse

    Benson, L.V.; Leach, D.L.

    1979-01-01

    During the summer of 1976 waters from tributaries, rivers, springs and wells were sampled in the Walker River Basin. Snow and sediments from selected sites were also sampled. All samples were analyzed for uranium and other elements. The resulting data provide an understanding of the transport of uranium within a closed hydrologic basin as well as providing a basis for the design of geochemical reconnaissance studies for the Basin and Range Province of the Western United States. Spring and tributary data are useful in locating areas containing anomalous concentrations of uranium. However, agricultural practices obscure the presence of known uranium deposits and render impossible the detection of other known deposits. Uranium is extremely mobile in stream waters and does not appear to sorb or precipitate. Uranium has a long residence time (2500 years) in the open waters of Walker Lake; however, once it crosses the sediment-water interface, it is reduced to the U(IV) state and is lost from solution. Over the past two million years the amount of uranium transported to the terminal point of the Walker River system may have been on the order of 4 ?? 108 kg. This suggests that closed basin termini are sites for significant uranium accumulations and are, therefore, potential sites of uranium ore deposits. ?? 1979.

  8. A case of Dandy-Walker malformation associated with occipital meningocele, microphthalamia, and cleft palate

    Microsoft Academic Search

    S. Nishimaki; H. Yoda; K. Seki; T. Kawakami; H. Akamatsu; Y. Iwasaki

    1990-01-01

    We present a case of Dandy-Walker malformation associated with occipital meningocele, microphthalmia, and cleft palate. Small numbers of cases of Dandy-Walker malformation with occipital meningocele have been described in the literature, but to our knowledge, non of these also had microphthalmia or cleft palate. This association suggests that time of intrauterine origin of Dandy-Walker syndrome was in the sixth or

  9. Pilot Joe Walker with the X-1E

    NASA Technical Reports Server (NTRS)

    1958-01-01

    A photo of the nose section of the X-1E with pilot Joe Walker suited for a flight at the NASA High-Speed Flight Station, Edwards, California. The dice and Little Joe are prominently displayed under the cockpit area. NASA employees and the crew chief of the plane worked long hours preparing a craft for flight. A break from the tedious task was a welcome reprieve at times; hence the private joke between a crew and their pilot evolved. If you know the craps game you've figured it out! (Little Joe is a dice player's slang term for two deuces.)

  10. Automatic Liver Segmentation Using the Random Walker Algorithm

    NASA Astrophysics Data System (ADS)

    Maier, F.; Wimmer, A.; Soza, G.; Kaftan, J. N.; Fritz, D.; Dillmann, R.

    In this paper we present a new method for fully automatic liver segmentation in computed tomography images. First, an initial set of seed points for the random walker algorithm is created. In this context, voxels belonging to air, fat tissue and ribcage are labeled as background. Furthermore, depending on the shape of the ribcage and voxel intensities, several seed points inside the liver are automatically selected as foreground. This seed mask is then used to initialize the segmentation algorithm. Our method was successfully tested on data of 22 patients.

  11. Finite perturbations on Friedmann-Robertson-Walker models. [Of cosmology

    SciTech Connect

    Ibanez, J.; Verdaguer, E.

    1986-07-01

    By dimensional reduction of solutions of Einstein's equations in five-dimensional vacuum, two metrics are derived which can be interpreted as finite cylindrical perturbations of the solitonic type on a radiative Friedmann-Robertson-Walker (FRW) cosmological background. A linear perturbative analysis is performed and is compared with the exact nonlinear results. The metrics are transformed to perfect fluid solutions representing finite soliton perturbations on a FRW background with stiff matter. One metric contains density modes, and the other includes the coupling between density and radiative modes. 30 references.

  12. Finite perturbations on perfect fluid Friedmann-Robertson-Walker models

    NASA Astrophysics Data System (ADS)

    Diaz, Mario C.; Gleiser, Reinaldo J.; Pullin, Jorge A.

    1989-04-01

    This paper analyzes the behavior of a family of finite exact perturbations of Friedmann-Robertson-Walker cosmologies constructed with the inverse scattering technique of Belinskii and Zakharov (1978). The application of this method in a five-dimensional spacetime with a massless scalar field and a subsequent Kaluza-Klein dimensional reduction makes it possible to construct models with perfect fluid material content in four dimensions. The behavior of the energy momentum and Weyl tensors are studied as characterizations of the gravitational and material behaviors. The important case of solitonic perturbations on de Sitter backgrounds is also treated.

  13. Science to Sustain Terminal Lakes: The Walker River Basin Study

    USGS Publications Warehouse

    U.S. Geological Survey

    2005-01-01

    Section 2507 of Public Law 107-171 (2002 Farm Bill) provided $200,000,000 to be used by the Secretary of the Interior, acting through the Commissioner of Reclamation, to provide water to at-risk natural desert terminal lakes. This bill was later amended under Public Law 108-7, Section 207 to include language 'Restoration of fish, wildlife, and associated habitats in watersheds of certain lakes'. The amendment specified that only Pyramid, Summit, and Walker Lakes in the State of Nevada were to be considered under Section 2507, Public Law 107-171.

  14. Treatment of Charcot foot and ankle with a prefabricated removable walker brace and custom insole

    Microsoft Academic Search

    Shawn Verity; Michael Sochocki; John M. Embil; Elly Trepman

    2008-01-01

    BackgroundRemovable walker braces have been used successfully to treat acute and chronic foot and ankle conditions including diabetic foot ulcers. We hypothesized that a removable walker brace may be successfully used in the management of the Charcot foot and ankle.

  15. Dissemination of Walker 256 carcinoma cells to rat skeletal muscle

    SciTech Connect

    Ueoka, H.; Hayashi, K.; Namba, T.; Grob, D.

    1986-03-05

    After injection of 10/sup 6/ Walker 256 carcinoma cells labelled with /sup 125/I-5-iodo-2'-deoxyuridine into the tail vein, peak concentration in skeletal muscle was 46 cells/g at 60 minutes, which was lower than 169202, 1665, 555, 198 and 133 cells/g, respectively, at 30 or 60 minutes in lung, liver, spleen, kidney and heart. Because skeletal muscle constitutes 37.4% of body weight, the total number of tumor cells was 2323 cells, which was much greater than in spleen, kidney and heart with 238, 271, and 85 cells, respectively, and only less than in lung and liver, at 222857 and 11700 cells, respectively. The total number in skeletal muscle became greater than in liver at 4 hours and than in lung at 24 hours. Ten minutes after injection of 7.5 x 10/sup 6/ Walker 256 carcinoma cells into the abdominal aorta of rats, a mean of 31 colony-forming cells were recovered from the gastrocnemius, while 106 cells were recovered from the lung after injection into the tail vein. These results indicate that a large number of viable tumor cells can be arrested in skeletal muscle through circulation. The rare remote metastasis of malignancies into skeletal muscle despite constantly circulating tumor cells does not appear to be due to poor dissemination of tumor cells into muscle but due to unhospitable environment of skeletal muscle.

  16. GeoFrame Walker Lane: Overview, Rationale, and Objectives

    NASA Astrophysics Data System (ADS)

    Stockli, D. F.

    2006-12-01

    GeoFrame is an integrative geologic initiative that takes a multi-dimensional view of the building and modification of the North American continent by systematic integration of geologic and geochronometric investigations and the results from unprecedented geophysical imaging as part of the Earthscope Program. The GeoFrame effort envisions these focus site investigations to entail map-scale arrays of passive source seismic receivers and associated active source seismic studies and complementary geophysics in conjunction with geologic-based synthesis and targeted studies. One of these focus sites is the Walker Lane region in eastern California and western Nevada, situated between the Basin and Range province and the unextended Sierra Nevada block. This GeoFrame focus site workshop is particularly timely given the deployment schedule of the USArray "BigFoot" array. The Walker Lane intraplate deformation zone accommodates nearly ~25% of present-day relative motion between the Pacific and North American plates and might represent an incipient plate boundary. It provides a world-class example of the present modification of continental lithosphere by the process of transcurrent faulting and rifting and offers the opportunity to seamlessly integrate surface geology, structural geology, petrology, geo- and thermochronology, and the history of the continental lithosphere with ongoing processes in the Earth's mantle. It affords opportunities to address a number of questions posed within Earthscope such as: mechanisms of strain transfer, the role of lithospheric rheology in strain localization and seismic response, the nature and timescales of transient fault behavior, and the role of magmas and fluids in deforming lithosphere. Implicit in the design and implementation of Earthscope is the recognition that progress on issues such as these requires an integrative geophysical and geological investigation of the Walker Lane. As such, it will open new avenues of collaboration and identify new research needs and opportunities. We anticipate the integration of results and efforts with ongoing Earthscope projects, such as Sierra Nevada efforts of SNEP as well as the NSF Margins Rupturing of Continental Lithosphere (RCL) initiative in the Gulf of California by continuing the work onshore from the Gulf of California to the north into Nevada.

  17. Towards Multi-fueled DNA walker on DNA trails

    NASA Astrophysics Data System (ADS)

    Nishikawa, Akio; Ohtake, Kazumasa; Tanaka, Fumiaki; Hagiya, Masami

    2008-10-01

    Basic idea and preliminary experimental results for photo-controllable DNA tiles are described. Although self-assembly of DNA cross tiles is an established technique, it only results in a static structure controlled by sequence design of sticky ends. For realizing dynamic control of DNA nanostructures, multi-fueled approach to self-assembly of DNA cross tiles is introduced. It is based on thermal-fuel, pH-fuel and photo-fuel. We already verified their basic behaviors in test tubes. In addition, we started to examine them for DNA walker on DNA trails made of DNA cross tiles. Especially, azobenzene intercalation groups for the sticky ends in DNA cross tiles are useful for photo-fuel, as they can control the assembly process with irradiation of UV/visible light. Preliminary results concerning the DNA cross tiles with azobenzene are also described briefly.

  18. Higgs effective potential in a perturbed Robertson-Walker background

    E-print Network

    Antonio L. Maroto; Francisco Prada

    2014-12-15

    We calculate the one-loop effective potential of a scalar field in a Robertson-Walker background with scalar metric perturbations. A complete set of orthonormal solutions of the perturbed equations is obtained by using the adiabatic approximation for comoving observers. After analyzing the problem of renormalization in inhomogeneous backgrounds, we get the explicit contribution of metric perturbations to the effective potential. We apply these results to the Standard Model Higgs field and evaluate the effects of metric perturbations on the Higgs mass and on its vacuum expectation value. Space-time variations are found, which are proportional to the gravitational slip parameter, with a typical amplitude of the order of $\\Delta\\phi/\\phi\\simeq 10^{-11}$ on cosmological scales. We also discuss possible astrophysical signatures in the Solar System and in the Milky Way that could open new possibilities to explore the symmetry breaking sector of the electroweak interactions.

  19. The Walker circulation, diabatic heating, and outgoing longwave radiation

    NASA Astrophysics Data System (ADS)

    Stechmann, Samuel N.; Ogrosky, H. Reed

    2014-12-01

    For the tropical atmosphere on planetary scales, it is common to model the circulation using strong damping. Here with new data analysis techniques, evidence suggests that damping can actually be neglected. Specifically, near the equator, the east-west overturning circulation is in agreement with the undamped wave response to atmospheric heating. To estimate the heating, satellite observations of outgoing longwave radiation (OLR) are used. Frequently, OLR is used as a heuristic indicator of cloudiness. Here the results further suggest that OLR variations are actually proportional to diabatic heating variations, with a proportionality constant of 18 W m-2 (K d-1)-1. While the agreement holds best over long time averages of years or decades, it also holds over shorter periods of one season or 1 month. Consequently, it is suggested that the strength of the Walker circulation—and its evolution in time—could be estimated using satellite data.

  20. The Walker circulation, diabatic heating, and outgoing longwave radiation

    NASA Astrophysics Data System (ADS)

    Stechmann, S. N.; Ogrosky, H. R.

    2014-12-01

    For the tropical atmosphere on planetary scales, it is common to model the circulation using strong damping. Here, with new data analysis techniques, evidence suggests that damping can actually be neglected. Specifically, near the equator, the east--west overturning circulation is in agreement with the undamped wave response to atmospheric heating. To estimate the heating, satellite observations of outgoing longwave radiation (OLR) are used. Frequently OLR is used as a heuristic indicator of cloudiness. Here, the results further suggest that OLR variations are actually proportional to total diabatic heating variations, with a proportionality constant of 18 W m-2 (K/day)-1. While the agreement holds best over long time averages of years or decades, it also holds over shorter periods of one season or one month. Consequently, it is suggested that the strength of the Walker circulation -- and its evolution in time -- could be estimated using satellite data.

  1. Glan Morfa Community Woodland Jeanette Mays, Collette Hughes, Peter Smith & Jimmy Walker (MRRA)

    E-print Network

    Glan Morfa Community Woodland Jeanette Mays, Collette Hughes, Peter Smith & Jimmy Walker (MRRA areas may have reduced anti-social behaviour. Excellent interpretation - leaflets, signs and Welsh Assembly Government. #12;Glan Morfa Community Woodland Jeanette Mays, Collette Hughes, Peter Smith

  2. 21 CFR 890.3790 - Cane, crutch, and walker tips and pads.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3790 Cane, crutch, and walker tips and pads. (a)...

  3. Cleantech to Market Projects Spring 2011 1. Residential Ventilation Controller; PI -Iain Walker

    E-print Network

    Kammen, Daniel M.

    Davenport This facility will contain test beds for building systems integration Ventilation Controller; PI - Iain Walker As homes become more airtight optimizing for energy efficiency. Researchers have designed a smart ventilation system

  4. Spacetime Emergence of the Robertson-Walker Universe from a Matrix Model

    SciTech Connect

    Erdmenger, Johanna; Meyer, Rene [Max-Planck-Institut fuer Physik, 80805 Munich (Germany); Park, Jeong-Hyuck [Max-Planck-Institut fuer Physik, 80805 Munich (Germany); Dept. of Physics, Sogang University, Seoul 121-742 (Korea, Republic of)

    2007-06-29

    Using a novel, string theory-inspired formalism based on a Hamiltonian constraint, we obtain a conformal mechanical system for the spatially flat four-dimensional Robertson-Walker Universe. Depending on parameter choices, this system describes either a relativistic particle in the Robertson-Walker background or metric fluctuations of the Robertson-Walker geometry. Moreover, we derive a tree-level M theory matrix model in this time-dependent background. Imposing the Hamiltonian constraint forces the spacetime geometry to be fuzzy near the big bang, while the classical Robertson-Walker geometry emerges as the Universe expands. From our approach, we also derive the temperature of the Universe interpolating between the radiation and matter dominated eras.

  5. V.1Semi-topological K-Theory Eric M. Friedlander and Mark E. Walker *

    E-print Network

    Sequence.......................................................................... 907 Generalized Cycle that involve challenging problems concerning both algebraic cycles and algebraic K-theory. Our expectationV.1Semi-topological K-Theory Eric M. Friedlander and Mark E. Walker * 1.1 Introduction

  6. 21 CFR 890.3790 - Cane, crutch, and walker tips and pads.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3790 Cane, crutch, and walker tips and pads. (a)...

  7. 21 CFR 890.3790 - Cane, crutch, and walker tips and pads.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3790 Cane, crutch, and walker tips and pads. (a)...

  8. 21 CFR 890.3790 - Cane, crutch, and walker tips and pads.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3790 Cane, crutch, and walker tips and pads. (a)...

  9. 21 CFR 890.3790 - Cane, crutch, and walker tips and pads.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3790 Cane, crutch, and walker tips and pads. (a)...

  10. Spacetime emergence of the robertson-walker universe from a matrix model.

    PubMed

    Erdmenger, Johanna; Meyer, René; Park, Jeong-Hyuck

    2007-06-29

    Using a novel, string theory-inspired formalism based on a Hamiltonian constraint, we obtain a conformal mechanical system for the spatially flat four-dimensional Robertson-Walker Universe. Depending on parameter choices, this system describes either a relativistic particle in the Robertson-Walker background or metric fluctuations of the Robertson-Walker geometry. Moreover, we derive a tree-level M theory matrix model in this time-dependent background. Imposing the Hamiltonian constraint forces the spacetime geometry to be fuzzy near the big bang, while the classical Robertson-Walker geometry emerges as the Universe expands. From our approach, we also derive the temperature of the Universe interpolating between the radiation and matter dominated eras. PMID:17678078

  11. ISS Update: Astronaut Shannon Walker â?? 07.17.2012 - Duration: 19 minutes.

    NASA Video Gallery

    In the International Space Station flight control room at NASAâ??s Johnson Space Center, Houston, ISS Update commentator Amiko Kauderer interviewed Shannon Walker, NASA astronaut and Expedition 24 ...

  12. Artificial Muscle: Light-Fueled Microscopic Walkers (Adv. Mater. 26/2015).

    PubMed

    Zeng, Hao; Wasylczyk, Piotr; Parmeggiani, Camilla; Martella, Daniele; Burresi, Matteo; Wiersma, Diederik Sybolt

    2015-07-01

    On page 3883, H. Zeng, D. S. Wiersma, and co-workers report the first light-powered microscopic artificial walker equipped with a liquid-crystalline elastomer muscle. The walker is fabricated by direct laser writing, is smaller than any known living terrestrial creatures, and is capable of several autonomous locomotions on different surfaces. The scanning electron beam microscope image shows a microwalker crawling on human hair. PMID:26149360

  13. A simple 3D straight-legged passive walker with flat feet and ankle springs

    Microsoft Academic Search

    Terumasa Narukawa; Kazuto Yokoyama; Masaki Takahashi; Kazuo Yoshida

    2008-01-01

    To date, most passive walkers have been designed with arc-shaped feet rigidly attached to the legs. We developed a simple 3D straight-legged passive walker with flat feet and ankle springs. The flat feet are connected to the legs with springs at the ankles that produce torsional force while the stance leg is on the ground, mimicking the motion of simple

  14. Motor properties from persistence: a linear molecular walker lacking spatial and temporal asymmetry

    NASA Astrophysics Data System (ADS)

    Zuckermann, Martin J.; Angstmann, Christopher N.; Schmitt, Regina; Blab, Gerhard A.; Bromley, Elizabeth HC; Forde, Nancy R.; Linke, Heiner; Curmi, Paul MG

    2015-05-01

    The stepping direction of linear molecular motors is usually defined by a spatial asymmetry of the motor, its track, or both. Here we present a model for a molecular walker that undergoes biased directional motion along a symmetric track in the presence of a temporally symmetric chemical cycle. Instead of using asymmetry, directionality is achieved by persistence. At small load force the walker can take on average thousands of steps in a given direction until it stochastically reverses direction. We discuss a specific experimental implementation of a synthetic motor based on this design and find, using Langevin and Monte Carlo simulations, that a realistic walker can work against load forces on the order of picoNewtons with an efficiency of ?18%, comparable to that of kinesin. In principle, the walker can be turned into a permanent motor by externally monitoring the walker’s momentary direction of motion, and using feedback to adjust the direction of a load force. We calculate the thermodynamic cost of using feedback to enhance motor performance in terms of the Shannon entropy, and find that it reduces the efficiency of a realistic motor only marginally. We discuss the implications for natural protein motor performance in the context of the strong performance of this design based only on a thermal ratchet.

  15. Dynamics of unvisited sites in the presence of mutually repulsive random walkers

    NASA Astrophysics Data System (ADS)

    Das, Pratap Kumar; Dasgupta, Subinay; Sen, Parongama

    2007-06-01

    We have considered the persistence of unvisited sites of a lattice, i.e., the probability S(t) that a site remains unvisited till time t in the presence of mutually repulsive random walkers in one dimension. The dynamics of this system has direct correspondence to that of the domain walls in a certain system of Ising spins where the number of domain walls becomes fixed following a zero-temperature quench. Here we get the result that S(t) ~ exp(-?t?) where ? is close to 0.5 and ? a function of the density of the walkers ?. The fraction of persistent sites in the presence of independent walkers of density ?' is known to be S^\\prime (t) = \\exp\\big({-}2 \\sqrt{\\vphantom{A^A}\\smash{\\{\\frac{2{\\pi}} \\rho^\\prime t^{1/2}}}}\\big) . We show that a mapping of the interacting walkers' problem to the independent walkers' problem is possible with ?' = ?/(1 - ?) provided ?' and ? are small. We also discuss some other intricate results obtained in the interacting walkers' case.

  16. Chemotaxing and haptotaxing random walkers having directional persistence

    NASA Astrophysics Data System (ADS)

    Kwon, Tae Goo; Kyoungjin Lee Team; Taeseok Daniel Yang Team

    2015-03-01

    Biological cell crawling is a rather complex process involving various bio-chemical and bio-mechanical processes, many of which are still not well understood. The difficulties in understanding the crawling are originating not just from cell-intrinsic factors but from their complex social interactions, cell-to-substrate interactions and nonlinear responses toward extrinsic factors. Here, in this report we investigate chemotactic behavior of mathematical model cells that naturally have directional persistence. A cell density is measured as a function of time and space, then the resulting steady state is compared with that of the well-known Keller-Segal model, which describes a population of chemotactic random walker. Then, we add a cell-to-cell interaction, mimicking a ``haptotaxis'' mediated interaction, to the model and access its role as for altering the steady-state cell density profile. This mathematical model system, which we have developed and considered in this work, can be quite relevant to the chemotactic responses of interacting immune cells, like microglia, moving toward and around a site of wound, as for an example. We conclude by discussing some relevant recent experimental findings.

  17. Sandpile models and random walkers on finite lattices.

    PubMed

    Shilo, Yehiel; Biham, Ofer

    2003-06-01

    Abelian sandpile models, both deterministic, such as the Bak, Tang, Wiesenfeld (BTW) model [P. Bak, C. Tang, and K. Wiesenfeld, Phys. Rev. Lett. 59, 381 (1987)] and stochastic, such as the Manna model [S.S. Manna, J. Phys. A 24, L363 (1991)] are studied on finite square lattices with open boundaries. The avalanche size distribution P(L)(n) is calculated for a range of system sizes, L. The first few moments of this distribution are evaluated numerically and their dependence on the system size is examined. The sandpile models are conservative in the sense that grains are conserved in the bulk and can leave the system only through the boundaries. It is shown that the conservation law provides an interesting connection between the sandpile models and random-walk models. Using this connection, it is shown that the average avalanche sizes (L) for the BTW and Manna models are equal to each other, and both are equal to the average path length of a random walker starting from a random initial site on the same lattice of size L. This is in spite of the fact that the sandpile models with deterministic (BTW) and stochastic (Manna) toppling rules exhibit different critical exponents, indicating that they belong to different universality classes. PMID:16241299

  18. Virtual Slope Control of a Forward Dynamic Bipedal Walker

    PubMed Central

    Russell, S.; Granata, K. P.; Sheth, P.

    2006-01-01

    Active joint torques are the primary source of power and control in dynamic walking motion. However the amplitude, rate, timing and phasic behavior of the joint torques necessary to achieve a natural and stable performance are difficult to establish. The goal of this study was to demonstrate the feasibility and stable behavior of an actively controlled bipedal walking simulation wherein the natural system dynamics were preserved by an active, nonlinear, state-feedback controller patterned after passive downhill walking. A two degree-of-freedom, forward-dynamic simulation was implemented with active joint torques applied at the hip joints and stance leg ankle. Kinematic trajectories produced by the active walker were similar to passive dynamic walking with active joint torques influenced by prescribed walking velocity. The control resulted in stable steady-state gait patterns, i.e. eigenvalue magnitudes of the stride function were less than one. The controller coefficient analogous to the virtual slope was modified to successfully control average walking velocity. Furture developments are necessary to expand the range of walking velocities. PMID:15868794

  19. A jump persistent turning walker to model zebrafish locomotion.

    PubMed

    Mwaffo, Violet; Anderson, Ross P; Butail, Sachit; Porfiri, Maurizio

    2015-01-01

    Zebrafish are gaining momentum as a laboratory animal species for the investigation of several functional and dysfunctional biological processes. Mathematical models of zebrafish behaviour are expected to considerably aid in the design of hypothesis-driven studies by enabling preliminary in silico tests that can be used to infer possible experimental outcomes without the use of zebrafish. This study is motivated by observations of sudden, drastic changes in zebrafish locomotion in the form of large deviations in turn rate. We demonstrate that such deviations can be captured through a stochastic mean reverting jump diffusion model, a process that is commonly used in financial engineering to describe large changes in the price of an asset. The jump process-based model is validated on trajectory data of adult subjects swimming in a shallow circular tank obtained from an overhead camera. Through statistical comparison of the empirical distribution of the turn rate against theoretical predictions, we demonstrate the feasibility of describing zebrafish as a jump persistent turning walker. The critical role of the jump term is assessed through comparison with a simplified mean reversion diffusion model, which does not allow for describing the heavy-tailed distributions observed in the fish turn rate. PMID:25392396

  20. Physical Activity, Weight Status, and Neighborhood Characteristics of Dog Walkers

    PubMed Central

    Coleman, Karen J.; Rosenberg, Dori E.; Conway, Terry L.; Sallis, James F.; Saelens, Brian E.; Frank, Lawrence D.; Cain, Kelli

    2008-01-01

    Objective This study examined how demographics, physical activity, weight status, and neighborhood characteristics varied among households with and without dogs. Method Participants aged 20 to 65 years (N = 2199, 52% male, 75% white, Mean age = 45) were recruited from 32 neighborhoods in the Seattle, WA and Baltimore, MD regions during 2002 – 2005. Dog ownership, dog walking, education, height, weight, and family income were self-reported. Minutes of moderate to vigorous physical activity (MVPA) were measured objectively by 7-day accelerometry. Results Dog walking was associated with a higher proportion of participants who met national recommendations for MVPA (53%) when compared to those who had but did not walk their dog (33%) and to non-dog owners (46%). There were significantly fewer obese dog walkers (17%) when compared to both owners who did not walk their dogs (28%) and non-owners (22%). Dog owners who walked their dogs were more likely to live in high-walkable neighborhoods when compared to dog owners who did not walk their dogs. Conclusion Dog walking may promote physical activity and contribute to weight control. Dog walking appears to be a mechanism by which residents of high-walkable neighborhoods obtain their physical activity. PMID:18572234

  1. Does the Walker Lane extend through the Nevada test site region

    SciTech Connect

    Fridrich, C.; O'Leary, D. (Geological Survey, Denver, CO (United States). Denver Federal Center)

    1993-04-01

    The southeastern terminus of the Walker Lane is poorly defined and poorly understood. Recent work in and around the Nevada Test Site (NTS) suggests the presence of a structural zone that may be an extension of the Walker Lane, and that may be continuous with the Las Vegas valley shear zone farther to the southeast. Unlike the Walker Lane, large through-going strike-slip faults have not been found in the NTS zone. Instead, the strike-slip faults present are few, are relatively short, commonly consist of diffuse fault zones, are interconnected poorly if at all, and largely appear to represent zones of accommodation between domains in which extension occurred at different times and to different degrees. However, the majority of these right-slip and left-slip faults are northwest-trending and northeast-trending, respectively, suggesting that plate motions may have played a role in the creation of these accommodation zones. An obstacle to understanding the NTS zone is that major ignimbrite sheets and calderas of the southwestern Nevada volcanic field (SNVF) formed in this zone at the height of late Tertiary tectonic activity, possibly burying much of the structural evidence. The NTS zone could represent an intersection of the Walker Lane with another major structural feature, a significant bend in the Walker Lane, or a transtensional tear that localized accommodation structures as well as the prominent late Miocene calderas of the SNVF. Ongoing field work is aimed at determining which of these and competing interpretations is best.

  2. The Fire-Walker’s High: Affect and Physiological Responses in an Extreme Collective Ritual

    PubMed Central

    Fischer, Ronald; Xygalatas, Dimitris; Mitkidis, Panagiotis; Reddish, Paul; Tok, Penny; Konvalinka, Ivana; Bulbulia, Joseph

    2014-01-01

    How do people feel during extreme collective rituals? Despite longstanding speculation, few studies have attempted to quantify ritual experiences. Using a novel pre/post design, we quantified physiological fluctuations (heart rates) and self-reported affective states from a collective fire-walking ritual in a Mauritian Hindu community. Specifically, we compared changes in levels of happiness, fatigue, and heart rate reactivity among high-ordeal participants (fire-walkers), low-ordeal participants (non-fire-walking participants with familial bonds to fire-walkers) and spectators (unrelated/unknown to the fire-walkers). We observed that fire-walkers experienced the highest increase in heart rate and reported greater happiness post-ritual compared to low-ordeal participants and spectators. Low-ordeal participants reported increased fatigue after the ritual compared to both fire-walkers and spectators, suggesting empathetic identification effects. Thus, witnessing the ritualistic suffering of loved ones may be more exhausting than experiencing suffering oneself. The findings demonstrate that the level of ritual involvement is important for shaping affective responses to collective rituals. Enduring a ritual ordeal is associated with greater happiness, whereas observing a loved-one endure a ritual ordeal is associated with greater fatigue post-ritual. PMID:24586315

  3. Diffusion-limited reactions and mortal random walkers in confined geometries

    E-print Network

    Ingo Lohmar; Joachim Krug

    2008-11-24

    Motivated by the diffusion-reaction kinetics on interstellar dust grains, we study a first-passage problem of mortal random walkers in a confined two-dimensional geometry. We provide an exact expression for the encounter probability of two walkers, which is evaluated in limiting cases and checked against extensive kinetic Monte Carlo simulations. We analyze the continuum limit which is approached very slowly, with corrections that vanish logarithmically with the lattice size. We then examine the influence of the shape of the lattice on the first-passage probability, where we focus on the aspect ratio dependence: Distorting the lattice always reduces the encounter probability of two walkers and can exhibit a crossover to the behavior of a genuinely one-dimensional random walk. The nature of this transition is also explained qualitatively.

  4. Diffusion-Limited Reactions and Mortal Random Walkers in Confined Geometries

    NASA Astrophysics Data System (ADS)

    Lohmar, Ingo; Krug, Joachim

    2009-01-01

    Motivated by the diffusion-reaction kinetics on interstellar dust grains, we study a first-passage problem of mortal random walkers in a confined two-dimensional geometry. We provide an exact expression for the encounter probability of two walkers, which is evaluated in limiting cases and checked against extensive kinetic Monte Carlo simulations. We analyze the continuum limit which is approached very slowly, with corrections that vanish logarithmically with the lattice size. We then examine the influence of the shape of the lattice on the first-passage probability, where we focus on the aspect ratio dependence: Distorting the lattice always reduces the encounter probability of two walkers and can exhibit a crossover to the behavior of a genuinely one-dimensional random walk. The nature of this transition is also explained qualitatively.

  5. Doping and high-level endurance walkers. Knowledge and representation of a prohibited practice.

    PubMed

    Laure, P; Reinsberger, H

    1995-09-01

    The purpose of this study is the representation of doping in high-level endurance walkers, based on a sample survey by questionnaire. The analysis of data shows that for walkers, doping seems only to be considered through its potential benefits. Increasing performance, wish to win and money are the three principal motives to use it, especially anabolic steroids and amphetamines. They think that analgesic injections should not be considered as doping. Thus, they are agreeing with drug testing but not with definition of doping in sport. In their circle, 41% of all subjects have heard of endurance walkers using ergogenic drugs. The need for better drug education is expressed by these results. PMID:8775652

  6. Wigner rotation via Fermi-Walker transport and relativistic EPR correlations in the Schwarzschild spacetime

    NASA Astrophysics Data System (ADS)

    Bakke, K.; Furtado, C.; Carvalho, A. M. De M.

    2015-04-01

    The Wigner rotation angle for a particle in a circular motion in the Schwarzschild spacetime is obtained via the Fermi-Walker transport of spinors. Then, by applying the Wentzel, Kramers, Brillouin (WKB) approximation, a possible application of the Fermi-Walker transport of spinors in relativistic Einstein-Podolsky-Rosen (EPR) correlations is discussed, where it is shown that the spins of the correlated particle undergo a precession in an analogous way to that obtained by Terashima and Ueda [H. Terashima and M. Ueda, Phys. Rev. A 69, 032113 (2004)] via the application of successive infinitesimal Lorentz transformations. Moreover, from the WKB approach, it is also shown that the degree of violation of the Bell inequality depends on the Wigner rotation angle obtained via the Fermi-Walker transport. Finally, the relativistic effects from the geometry of the spacetime and the accelerated motion of the correlated particles is discussed in the nonrelativistic limit.

  7. Change in the size of Walker Lake during the past 5000 years

    USGS Publications Warehouse

    Benson, L.V.; Meyers, P.A.; Spencer, R.J.

    1991-01-01

    In 1984, a 12-m sediment core (WLC84-8) was taken from the deepest part of Walker Lake. Samples of the core were analysed for diatoms, pollen, carbonate mineralogy, magnesium content, ??18O and ??13C values of the total inorganic fractin, ??18O and ??13C values of Limnocythere ceriotuberosa, ??13C values of the total organic fraction, grain size, and magnetic susceptibility. The data indicate that Walker Lake became shallow and probably desiccated between ???5300-4800 and 2700-2100 yr B.P.. Each of the organic and inorganic proxy indicators of lake size discussed in this paper was useful in determining the presence of the shallow-lake intervals. However, none of the indicators was useful in determining the cause of the shallow-lake intervals. Instead, the types of fish living in Walker Lake prior to 1940 were used to demonstrate that shallow-lake intervals resulted from diversion of the Walker River and not from climatic aridity. Major changes in mineralogy and magnesium content of carbonates and major changes in diatom populations with time were found to be a function of the chemical evolution of Walker Lake combined with changing lake size. The stable isotopes of oxygen and carbon were found to be good indicators of lake volume changes. A lake-level record for Walker Lake constructed from stable-isotope data was found to be similar to a lake-level record constructed using tufa and tree-stump data. Both records indicate relatively high lake levels between 4800-2700 yr B.P., at 1250 yr B.P., and within the last 300 yr. Substantial declines in lake level occurred ???2000 and ???1000 yr B.P. ?? 1991.

  8. Late Holocene lake-level fluctuations in Walker Lake, Nevada, USA Fasong Yuana,b,, Braddock K. Linsleya

    E-print Network

    Linsley, Braddock K.

    Late Holocene lake-level fluctuations in Walker Lake, Nevada, USA Fasong Yuana,b,, Braddock K d U.S. Geological Survey, 12201 Sunrise Valley Drive, Reston, VA 20192, USA Received 22 August 2005; received in revised form 11 January 2006; accepted 5 March 2006 Abstract Walker Lake, a hydrologically

  9. In search of wholeness: same gender relationships in Alice Walker's novels 

    E-print Network

    Wink, Amy Laura

    1989-01-01

    received much tritical attention for her third novel T~he Cuter Pur e. While this recent barrage of criticism has focused on her third novel, Walker's first two novels play an important role in the development and evolution of her vision. The Third Ufe... of Gran C eland (1970) and Meridian (1976) are the first two evolutionary steps in Walker's attempts to reveal the significance of same gender relationships and thsa role in the self-definition process. T~he Cuter Pur le focuses on one Black woman...

  10. A review of "Law, Crime and English Society, 1660-1830" by Norma Landau and "Crime, Gender and Social Order in Early Modern England" by Garthine Walker 

    E-print Network

    Sherman, Donovan

    2010-01-01

    fiction and fact?that propels Walker?s revitalization of the past. Early modernity is, for Walker and the authors of Law, Crime and English Society, a con- stellation of competing discourses that, regardless of how untrue they may seem in hindsight...

  11. Obituary: Alastair Graham Walker Cameron, 1925-2005

    NASA Astrophysics Data System (ADS)

    Truran, James W.; Thielemann, F.-K.; Cowan, J. J.

    2005-12-01

    Alastair Graham Walker Cameron, one of the most creative and influential astrophysicists of his generation, passed away on 3 October 2005, at the age of 80, at his home in Tucson. Subsequent to his retirement from Harvard University, where he had been a member of the faculty from 1973 through 1999, Cameron remained active as a Senior Research Scientist at the Lunar and Planetary Laboratory of the University of Arizona. Cameron had a distinguished career during which he made outstanding contributions both in scientific research and in public service to science. Notable among the latter are the years he spent as Chairman of the Space Science Board of the National Academy of Sciences from 1976 to 1982. He was a member of the National Academy of Sciences and the recipient of a number of awards for his diverse contributions to the sciences, including the J. Lawrence Smith Medal of the National Academy of Sciences in 1988, the Leonard Medal of the American Meteoritical Society in 1994, the Henry Norris Russell Lectureship of the American Astronomical Society in 1997, and the Hans A. Bethe prize of the Division of Nuclear Physics of the American Physical Society for 2006, for outstanding work in nuclear physics and astrophysics. He was enormously active in the organization of conferences and workshops and in an editorial capacity, for a number of journals in astronomy, astrophysics, and space physics. Over the course of his career, he made seminal contributions to such diverse areas of astronomical and astrophysical research as nuclear reactions in stars, nucleosynthesis, the abundances of the elements in the Solar System, meteoritics, stellar evolution, neutron stars, the origin of the Solar System, the physics of planets and planetary atmospheres, and the origin of the Moon. Born on 21 June 1925 in Winnipeg, Manitoba, Cameron received his undergraduate degree from the University of Manitoba and his doctorate in nuclear physics from the University of Saskatchewan in 1952. He taught for two years at Iowa State and then spent seven years as a Senior Research Officer at Chalk River. It was from this period that his important early contributions to nuclear astrophysics emerged. His research addressed a broad range of problems concerning the origin of the elements, culminating in the publication in 1957 of a discussion of stellar evolution and nucleosynthesis which, together with the paper by E.M. Burbidge, G.F. Burbidge, W.A. Fowler, and F. Hoyle, substantially defined the field of nucleosynthesis as we understand it today. Cameron joined the staff of the NASA Institute for Space Studies in New York and served as a Senior Scientist from 1961 to 1966, then continued on to the Belfer Graduate School of Science of Yeshiva University in New York, prior to moving to Harvard. Working with an increasing number of graduate students and postdocs, Cameron continued his studies in nuclear physics, concentrating on building systematics of nuclear mass formulae, nuclear level densities, thermonuclear reaction rates, and weak interaction rates. These nuclear systematics, coupled to early calculations of supernova explosions, enabled the first detailed numerical investigations of explosive nucleosynthesis from which the identification of 56Ni as the dominant product emerged. During these years, Cameron's research activities and interests expanded considerably to encompass broad areas of space physics, including specifically the origin of the Solar System. Notable here is the significant role he played in the early formulation and development of the impact theory for the origin of the Moon. This theory posits - and early numerical simulations by Cameron and his collaborators confirmed - that the collision of a large, Mars sized object with the Earth early in its history yields debris from which the Moon can coalesce, and can account for both an iron-depleted Moon and the masses and angular momentum of the Earth-Moon system. Cameron was an extremely imaginative and productive scientist whose contributions profoundly influenced many areas of resear

  12. Interinstrument Consistency of the Yamax Digi-Walker Pedometer in Elementary School-Aged Children

    ERIC Educational Resources Information Center

    Barfield, J. P.; Rowe, David A.; Michael, Timothy J.

    2004-01-01

    A pedometer is a practical, inexpensive tool used to measure physical activity. Bassett et al. (1996) found that interinstrument consistency of the Yamax Digi-Walker was higher than four other pedometers when measuring distance walked in adults. The purpose of this study was to investigate the interinstrument consistency of the Yamax pedometer in…

  13. Sleep and the Time Course of Motor Skill Learning Matthew P. Walker,1

    E-print Network

    Walker, Matthew P.

    of sleep, and that selective disruption of rapid eye movement (REM) sleep prevents this overnightResearch Sleep and the Time Course of Motor Skill Learning Matthew P. Walker,1 Tiffany Brakefield 02115, USA Growing evidence suggests that sleep plays an important role in the process of procedural

  14. Walker, Figliozzi, Haire, and MacArthur 1 IDENTIFYING SURFACE TRANSPORTATION VULNERABILITIES AND

    E-print Network

    , prioritization, and impact assessment and can also used as a basis for more advanced analysis and scenario adaptation planning for surface transportation. KEYWORDS: Climate Change, Flooding, Landslide, Adaptation, Vulnerability, GIS #12;Walker, Figliozzi, Haire, and MacArthur 3 INTRODUCTION Our changing climate and response

  15. The Legal Dimension of RTI--Confusion Confirmed: A Response to Walker and Daves

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2012-01-01

    In this issue of "Learning Disability Quarterly" (LDQ), Professors Daves and Walker reply to my earlier LDQ article on confusion in the cases and commentary about the legal dimension of RTI. In this brief rejoinder, I show that their reply confirms rather than resolves the confusion in their original commentary in 2010. This persistent problem…

  16. ANDERSON ACCELERATION FOR FIXED-POINT ITERATIONS HOMER F. WALKER AND PENG NI

    E-print Network

    Walker, Homer F.

    ANDERSON ACCELERATION FOR FIXED-POINT ITERATIONS HOMER F. WALKER AND PENG NI Abstract. This paper concerns an acceleration method for fixed-point iterations that originated in work of D. G. Anderson-560], which we accordingly call Anderson acceleration here. This method has enjoyed considerable success

  17. MoonWalker, a lower limb exoskeleton able to sustain bodyweight using a passive force balancer

    Microsoft Academic Search

    Sébastien Krut; Michel Benoit; Etienne Dombre; François Pierrot

    2010-01-01

    This paper presents MoonWalker, a lower limb exoskeleton able to sustain part of a user's bodyweight. This orthosis can be used for rehabilitation, to help people having weak legs, or to help those suffering from a broken leg, to walk. It can also be used as an assistive device helping people carrying heavy loads. Its main characteristic is that a

  18. Collateral Damage: Veterans and Domestic Violence in Mari Sandoz's "The Tom-Walker"

    ERIC Educational Resources Information Center

    Bahr, Kathy

    2010-01-01

    "The Tom-Walker" combines the best of Sandoz's realism with her worst attempts at moralizing. Unable to divine exactly what political configuration right-wing post-World War II sentiments might take, Sandoz nevertheless feared a fascist uprising in this country. Perhaps because these concerns dominated her thoughts at the time, she allowed her…

  19. ACTIVITIES TO ATTRACT HIGH SCHOOL GIRLS TO COMPUTER SCIENCE Susan H. Rodger Ellen L. Walker

    E-print Network

    Rodger, Susan H.

    ACTIVITIES TO ATTRACT HIGH SCHOOL GIRLS TO COMPUTER SCIENCE Susan H. Rodger Ellen L. Walker for high school girls. These hands-on activities and interactive talks, presented mostly by female faculty, undergraduates, and graduate students, showed the girls the wide range of opportuni- ties in the eld of computer

  20. Improved Wafer-level Spatial Analysis for IDDQ Limit Setting Sagar Sabade D. M. H. Walker

    E-print Network

    Walker, Duncan M. "Hank"

    Improved Wafer-level Spatial Analysis for IDDQ Limit Setting Sagar Sabade D. M. H. Walker methodology for estimating the upper bound on the IDDQ of defect free chips by using wafer level spatial data. Such a methodology accounts for the change in IDDQ due to process variations across wafers

  1. Wafer Signature Analysis of IDDQ Test Data Sagar S. Sabade D. M. H. Walker

    E-print Network

    Walker, Duncan M. "Hank"

    Wafer Signature Analysis of IDDQ Test Data Sagar S. Sabade D. M. H. Walker Department of Computer. The concept of wafer signature is proposed. A wafer signature is obtained by sorting all IDDQ readings on a wafer for a vector. A break or jump in the wafer signature is considered to indicate defective chips

  2. Existence of black holes in Friedmann-Robertson-Walker universe dominated by dark energy

    E-print Network

    Zhong-Heng Li; Anzhong Wang

    2006-11-15

    We study the existence of black holes in a homogeneous and isotropic expanding Friedmann-Robertson-Walker (FRW) universe dominated by dark energy. We show that black holes can exist in such a universe by considering some specific McVittie solutions. Although these solutions violate all three energy conditions, the FRW background does satisfy the weak energy condition.

  3. Walker, Biol481T Sexual Selection, Behavior, and Mate Choice Page 1 of 8

    E-print Network

    Walker, Sean E.

    with sexual selection (e.g., Sexual Selection Theory, Empirical Methods Used to Study Sexual Selection, Mating Systems, Parental Investment, and Sexual Selection, and Alternative Mating Tactics and Strategies) and weWalker, Biol481T Sexual Selection, Behavior, and Mate Choice Page 1 of 8 California State

  4. Seeing the sky through Hubble's eye: The COSMOS SkyWalker

    E-print Network

    K. Jahnke; S. F. Sanchez; A. Koekemoer

    2006-07-23

    Large, high-resolution space-based imaging surveys produce a volume of data that is difficult to present to the public in a comprehensible way. While megapixel-sized images can still be printed out or downloaded via the World Wide Web, this is no longer feasible for images with 10^9 pixels (e.g., the Hubble Space Telescope Advanced Camera for Surveys [ACS] images of the Galaxy Evolution from Morphology and SEDs [GEMS] project) or even 10^10 pixels (for the ACS Cosmic Evolution Survey [COSMOS]). We present a Web-based utility called the COSMOS SkyWalker that allows viewing of the huge ACS image data set, even through slow Internet connections. Using standard HTML and JavaScript, the application successively loads only those portions of the image at a time that are currently being viewed on the screen. The user can move within the image by using the mouse or interacting with an overview image. Using an astrometrically registered image for the COSMOS SkyWalker allows the display of calibrated world coordinates for use in science. The SkyWalker "technique" can be applied to other data sets. This requires some customization, notably the slicing up of a data set into small (e.g., 256^2 pixel) subimages. An advantage of the SkyWalker is the use of standard Web browser components; thus, it requires no installation of any software and can therefore be viewed by anyone across many operating systems.

  5. Clinical and genetic distinction between Walker-Warburg syndrome and muscle- eye- brain disease

    Microsoft Academic Search

    B. Cormand; H. Pihko; M. Bayés; L. Valanne; P. Santavuori; B. Talim; R. Gershoni-Baruch; A. Ahmad; H. van Bokhoven; H. G. Brunner; T. Voit; H. Topaloglu; W. B. Dobyns; A.-E. Lehesjoki

    Article abstract—Background: Three rare autosomal recessive disorders share the combination of congenital muscular dystrophy and brain malformations including a neuronal migration defect: muscle- eye-brain disease (MEB), Walker- Warburg syndrome (WWS), and Fukuyama congenital muscular dystrophy (FCMD). In addition, ocular abnormalities are a constant feature in MEB and WWS. Lack of consistent ocular abnormalities in FCMD has allowed a clear clinical

  6. Dr Matthias Zahn | Dr Richard P Allan www.walker-institute.ac.uk

    E-print Network

    Zahn, Matthias

    Dr Matthias Zahn | Dr Richard P Allan www.walker-institute.ac.uk Figure 2: Vertical profiles associated with changing precipitation patterns. References Zahn, M. and R.P. Allan, 2011, Changes in water - Atmospheres, 116, D18111 Zahn, Matthias, Richard P. Allan, 2013, Climate Warming­Related Strengthening

  7. Spin-rotation interaction of alkali-metalHe-atom pairs Thad G. Walker

    E-print Network

    Thywissen, Joseph

    Spin-rotation interaction of alkali-metal­He-atom pairs Thad G. Walker Department of Physics of the spin-rotation coupling between alkali-metal atoms and He atoms is presented. Rotational distortions results. For spin-exchange optical pumping, the results suggest that lighter alkali-metal atoms would

  8. The Static Hedging of CDO Tranche Correlation Risk1 Michael B. Walker2,3

    E-print Network

    Walker, Michael B.

    for the challenging period following the May 5, 2005 downgrade of Ford and General Motors by Standard and Poor Department of Physics, University of Toronto, Toronto, ON M5S 1A7, CANADA; email: walker@physics.utoronto.ca the hedge ratio, the Gaussian copula correlation parameter is held constant. A difficulty

  9. If the Song Sounds the Same Check for Static: A Reply to Walker and Frimer

    ERIC Educational Resources Information Center

    Sherblom, Stephen A.

    2009-01-01

    The "care challenge" is shown to be both broader and more successful than Walker and Frimer's (this issue, pp. 53-68) critique allows. The main philosophical and psychological tenets of the care challenge foreshadowed the direction of twenty-first century moral psychology.

  10. Zero moment point-measurements from a human walker wearing robot feet as shoes

    Microsoft Academic Search

    Philippe Sardain; Guy Bessonnet

    2004-01-01

    The anthropomorphic biped robot Bip is equipped with sensors for measuring the ground\\/feet forces in order to lo- calize the center of pressure (CoP) and zero moment point (ZMP). This paper focuses on experimental results regarding the evolu- tion of the ground contact forces, obtained from a human walker wearing the robot feet as shoes. First, one determines the influence

  11. Mary Broadfoot Walker (1888–1974): A Historic Discovery in Myasthenia gravis

    Microsoft Academic Search

    J. M. S. Pearce

    2005-01-01

    As a clinical entity, myasthenia gravis was not recognized until Samuel Wilks in 1877 described bulbar and peripheral muscular weakness. In the Lancet of June 2, 1934, the remarkable discovery of physostigmine treatment by Dr. Mary Walker was published, which was to become the mainstay of symptomatic treatment. A quiet and modest physician, she laboured with considerable success under many

  12. Stress tensor and conformal anomalies for massless fields in a Robertson-Walker universe

    Microsoft Academic Search

    T. S. Bunch; P. C. W. Davies

    1977-01-01

    We derive the unique, local vacuum stress tensor for electromagnetic, neutrino and massless scalar fields propagating in a Robertson-Walker background spacetime. The result is used to compute the numerical coefficients of the conformal trace anomalies from the known values of the Casimir energy in the Einstein universe.

  13. GECEM: Grid-Enabled Computational Electromagnetics David W. Walker and Jonathan P. Giddy

    E-print Network

    Walker, David W.

    GECEM: Grid-Enabled Computational Electromagnetics David W. Walker and Jonathan P. Giddy School geometry is then transferred to WeSC where it is used to solve a computational electromagnetics problem and visualised. Keywords: Computational electromagnetics, Grid, extended enterprise, mesh generation. 1

  14. Large Haptic Topographic Maps: MarsView and the Proxy Graph Algorithm Sean P. Walker

    E-print Network

    Salisbury, Kenneth

    Large Haptic Topographic Maps: MarsView and the Proxy Graph Algorithm Sean P. Walker Computer algorithm", a new haptic contact model. The proxy graph algorithm approxi- mates proven virtual proxy and zoom in on details. The hybrid system renders complex scenes at full vi- sual and haptic rates

  15. The movement patterns of a generic walker in a complex landscape

    NASA Astrophysics Data System (ADS)

    Opps, Sheldon; Arthurs, Michael; Silva, Marina

    2004-03-01

    A simulation model has been developed to examine the movement patterns of a generic walker in complex environments. This model is based on percolation theory and incorporates a novel technique for generating fractional brownian landscapes on a two-dimensional lattice. The principle features of the habitat, for example trees, coral reef, sand, etc, are attributed different fractal dimensions, D, and quality factors, Q, which measures the strength of interaction between the walker and the local environment. Additionally, the landscape is randomly decorated with obstacles, such as bumps and holes (such as defects in a metal). The walker moves across the habitat according to a set of rules which depend on Q, and has visual range that permits her to navigate around barriers or move towards preferred objects. In this study, we have systematically investigated how variations in D affect the connectivity of the landscape which, in turn, affects the movement patterns of a generic walker. We have attempted to quantify the functional dependence of the percolation threshold, Pc, on the fractal dimension. In addition, we utilize the radius of gyration, Rg, as a measure of movement path shape and size and investigate transitions in Rg as a function of D and Q.

  16. Tunable Networks from Thiolene Chemistry for Lithium Ion Catherine N. Walker,

    E-print Network

    Tew, Gregory N.

    ) by eliminating components such as the separator.3 Among commercially available batteries, lithium ion batteries to double the energy density and eliminate the volatile organic solvents, which pose a fire hazard.4Tunable Networks from Thiolene Chemistry for Lithium Ion Conduction Catherine N. Walker, Craig

  17. Fermi coordinates, simultaneity, and expanding space in Robertson-Walker cosmologies

    E-print Network

    Klein, David

    Fermi coordinates, simultaneity, and expanding space in Robertson-Walker cosmologies David Klein1-8313. Email: david.klein@csun.edu. 2Department of Mathematics, California State University, Northridge proper time t, deter- mines a notion of simultaneity and leads in a natural way to Hubble's law, d(t) vH

  18. Knee design for a bipedal walking robot based on a passive-dynamic walker

    E-print Network

    Baines, Andrew Griffin

    2005-01-01

    Passive-dynamic walkers are a class of robots that can walk down a ramp stably without actuators or control due to the mechanical dynamics of the robot. Using a passive-dynamic design as the basis for a powered robot helps ...

  19. Slowdown of the Walker circulation driven by tropical Indo-Pacific warming.

    PubMed

    Tokinaga, Hiroki; Xie, Shang-Ping; Deser, Clara; Kosaka, Yu; Okumura, Yuko M

    2012-11-15

    Global mean sea surface temperature (SST) has risen steadily over the past century, but the overall pattern contains extensive and often uncertain spatial variations, with potentially important effects on regional precipitation. Observations suggest a slowdown of the zonal atmospheric overturning circulation above the tropical Pacific Ocean (the Walker circulation) over the twentieth century. Although this change has been attributed to a muted hydrological cycle forced by global warming, the effect of SST warming patterns has not been explored and quantified. Here we perform experiments using an atmospheric model, and find that SST warming patterns are the main cause of the weakened Walker circulation over the past six decades (1950-2009). The SST trend reconstructed from bucket-sampled SST and night-time marine surface air temperature features a reduced zonal gradient in the tropical Indo-Pacific Ocean, a change consistent with subsurface temperature observations. Model experiments with this trend pattern robustly simulate the observed changes, including the Walker circulation slowdown and the eastward shift of atmospheric convection from the Indonesian maritime continent to the central tropical Pacific. Our results cannot establish whether the observed changes are due to natural variability or anthropogenic global warming, but they do show that the observed slowdown in the Walker circulation is presumably driven by oceanic rather than atmospheric processes. PMID:23151588

  20. Surveying The TeV Sky With Milagro G. P. Walker for the Milagro Collaboration

    E-print Network

    California at Santa Cruz, University of

    Surveying The TeV Sky With Milagro G. P. Walker for the Milagro Collaboration Los Alamos National highly variable or are extended. Milagro is such a TeV detector and has performed the deepest surveyV. OBSERVATIONS An all-sky survey was conducted with data collected between July 2000 and March 2006, using the A4

  1. Collaborative Music to Motivate Mathematics Learning Rodney T. Walker, Mark Guzdial

    E-print Network

    Guzdial, Mark

    Collaborative Music to Motivate Mathematics Learning Rodney T. Walker, Mark Guzdial Georgia-solving that makes the mathematics relevant and more easily learned (NCTM, 1998). Minority students, and African-Americans in particular, are among those most at risk for learning mathematics (Hawkins, Stancavage & Dossey, 1998

  2. Ascending auditory interneurons in the cricket Teleogryllus commodus (Walker): comparative physiology and direct connections with afferents

    Microsoft Academic Search

    R. M. Hennig

    1988-01-01

    Ascending auditory interneurons of the cricket,Teleogryllus commodus (Walker), were investigated using simultaneous intracellular and extracellular recording in order to identify units which had previously been characterized only by extracellular recording. The morphology and physiology of the large adapting unit (LAU: Fig. 1) and of the small tonic unit (STU: Fig. 2) ofTeleogryllus correspond well to those of the ascending neuron

  3. JAIST Robotic Walker control based on a two-layered Kalman filter

    Microsoft Academic Search

    Geunho Lee; Eui-Jung Jung; Takanori Ohnuma; Nak Young Chong; Byung-Ju Yi

    2011-01-01

    This paper presents a new control scheme of JAIST Active Robotic Walker (JARoW) developed to provide elderly people with sufficient ambulatory capability. Toward its practical use, our focus is placed on how to allow easier and reliable maneuverability by creating a natural user interface. Specifically, our challenge lies in providing a well-functioning controller by detecting what the user wants to

  4. Air Leakage of Furnaces and Air Handlers Iain S. Walker, Mike Lubliner, Darryl Dickerhoff,

    E-print Network

    Air Leakage of Furnaces and Air Handlers of California. #12;1 Air Leakage of Furnaces and Air Handlers Iain S. Walker, LBNL Mike Lubliner, Washington been made in reducing air leakage in residential and to a lesser extent small commercial forced air

  5. High Performance Sustainable School Design: Roy Lee Walker Elementary, McKinney, Texas.

    ERIC Educational Resources Information Center

    SHW Group, Inc., Dallas, TX.

    This document describes the sustainable features of the Roy Lee Walker Elementary School (Texas), a prototype "Eco Education" school that blends the physical environment with the student learning process while protecting the site. The document also presents the process of integrating sustainability criteria in all phases of the school's life…

  6. Dirac equation and energy levels of hydrogenlike atoms in Robertson-Walker metric

    Microsoft Academic Search

    Xu Chongming; Xu Dianyan

    1984-01-01

    Summary  The Dirac equation of the hydrogenlike atom in the Robertson-Walker metric is studied in this paper by means of tetrad formalism.\\u000a The decoupled Dirac equation is derived and energy levels of hydrogen atoms taking into account the cosmological radius are\\u000a obtained by using the perturbation expansion.

  7. Responses to Gizzard Shad Recovery following Selective Treatment in Walker County Lake, Alabama, 1996-1999

    Microsoft Academic Search

    Brian J. Irwin; Dennis R. DeVries; Gene W. Kim

    2003-01-01

    Gizzard shad Dorosoma cepedianum is an important prey fish that is capable of influencing both the upper and lower trophic levels in aquatic systems. Contrary to our predictions, during the 4 years after a selective reduction of gizzard shad in Walker County State Fishing Lake (WCL), Alabama, the sport fish population structure did not decline as gizzard shad abundance rebounded.

  8. Profile Soil Moisture Estimation Using the Modified IEM Jeffrey P. Walker1

    E-print Network

    Walker, Jeff

    Profile Soil Moisture Estimation Using the Modified IEM Jeffrey P. Walker1 , Peter A. Troch2 to the radar observation depth. A theoretical observation depth model is also proposed. It is shown that radar Microwave Signature Laboratory (EMSL) experiments. INTRODUCTION Soil moisture in the root zone is a key

  9. Active transtensional intracontinental basins: Walker Lane in the western Great Basin

    USGS Publications Warehouse

    Jayko, Angela S.; Bursik, Marcus

    2012-01-01

    The geometry and dimensions of sedimentary basins within the Walker Lane are a result of Plio-Pleistocene transtensive deformation and partial detachment of the Sierra Nevada crustal block from the North American plate. Distinct morpho-tectonic domains lie within this active transtensive zone. The northeast end of the Walker Lane is partly buried by active volcanism of the southern Cascades, and adjacent basins are filled or poorly developed. To the south, the basin sizes are moderate, 25–45km × 15–10 km, with narrow 8-12km wide mountain ranges mainly oriented N-S to NNE. These basins form subparallel arrays in discrete zones trending about 300° and have documented clockwise rotation. This is succeeded to the south by a releasing stepover domain ?85-100km wide, where the basins are elongated E-W to ENE, small (?15-30km long, 5-15km wide), and locally occupied by active volcanic centers. The southernmost part of the Walker Lane is structurally integrated, with high to extreme relief. Adjacent basins are elongate, 50-200km long and ?5 -20km wide. Variations in transtensive basin orientations in the Walker Lane are largely attributable to variations in strain partitioning. Large basins in the Walker Lane have 2-6km displacement across basin bounding faults with up to 3 km of clastic accumulation based on gravity and drill hole data. The sedimentary deposits of the basins may include interbedded volcanic deposits with bimodal basaltic and rhyolitic associations. The basins may include lacustrine deposits that record a wide range of water chemistry from cold fresh water conditions to saline-evaporative

  10. Obituary: Richard L. (Dick) Walker, Jr., 1938-2005

    NASA Astrophysics Data System (ADS)

    Pier, Jeffrey R.; Mason, Brian

    2005-12-01

    Dick Walker, 67, died 30 March 2005 in Flagstaff, AZ, following a long illness. He was born on 9 March 1938 in Hampton, Iowa and grew up in Waterloo, Iowa. As a child, Dick was fascinated with astronomy and built his own telescope. He saved his pennies and bought and read every book on the subject he could find. He also raised pigeons, naming four of them Hertzsprung, Hoyle, Gamow, and Kron. In 1957, the year Sputnik was launched, Dick began his college studies at the University of Northern Iowa in Cedar Falls. In 1959, he transferred to the State University of Iowa (subsequently renamed the University of Iowa) in Iowa City, where he earned a BA degree in astronomy and physics in 1963. He joined the staff of the U.S. Naval Observatory in Washington, DC, where he worked in the Time Service Division for a year before his assignment to the Astrometry and Astrophysics Division. Dick relocated to Flagstaff, AZ, in 1966 to continue his Naval Observatory service at the Flagstaff Station. His retirement in May 1999, ended a thirty-six-year career with USNO. Dick was first and foremost an observational astronomer. From the mid 1960s through the late 1970s, much of Dick's time was devoted to the measurement of binary stars, observing with the 12-inch and 26-inch refractors in Washington and later the 40-inch and 61-inch reflectors in Flagstaff. He also made many trips to Lick Observatory to work with the 36-inch Clark Refractor there. During this time he consulted with Charles Worley, who was observing on the 26-inch, to make sure time was well-spent examining doubles that could not be observed in Washington. This period of observing overlapped with the early years of speckle interferometry, and Dick's observations, made with the largest telescope used for micrometry at the time, were very important for ascertaining the veracity of this new technique. He was a studious and very careful observer of doubles and made over 8,000 measures, resulting in almost 3,000 mean positions. While measuring known systems for orbital analysis, he discovered 22 pairs (mostly additional components to these systems) and moving pairs, and his highlighting the rapid motion of these systems resulted in them being placed on many programs and led to the more definitive orbits of today. As a staff member of the Flagstaff Station, Dick was, for over 30 years, one of the principal observers on the 61-inch parallax program. He also ventured into other areas of astronomy, including planetary systems. He is credited with discovering the moon of Saturn, Epimetheus, in December 1966, with the USNO Flagstaff Station 61-inch Kaj Strand Astrometric Reflector. He also obtained photographic plates to determine accurate positions of the outer planets for the Voyager 2 approaches to Uranus in 1986 and Neptune in 1989. It is interesting to note that Dick's career in observational astronomy spanned three different eras of astronomical instrumentation and technique. He began his career doing eyeball astronomy, using a filar micrometer to measure double star separations. Photographic astronomy then became dominant and he took many thousands of plates. During the last ten years of his career, electronic cameras, primarily CCDs, replaced photographic plates. He readily adapted to the changing technologies. A man of many interests, Dick was fascinated by the history of astronomy, especially archeoastronomy, as well as Egyptology. He taught himself the language of hieroglyphics. In 1977, having accumulated several weeks of vacation time, he set off on a trek to walk the Nile for 500 miles from Aswan to Cairo. One night, in the town Asyut along the Nile, he was brought into the police station. The local inhabitants found it hard to credit his story that he was simply on a walk and questioned him as a possible Israeli spy. Following his retirement from the Naval Observatory, Dick consulted in a couple of construction projects. He designed the analemma and the skywalk star fields for the Koch Center for Science, Math, and Technology at Deerfield Academy in Massachusetts. He also c

  11. Late Quaternary seismic stratigraphic framework and paleolimnology of Walker Lake, Nevada

    NASA Astrophysics Data System (ADS)

    Friday, M.; Scholz, C. A.; Junium, C. K.

    2014-12-01

    Lake deposits can be used to assess past hydrological and atmospheric conditions and aid in understanding regional climate of the western Basin and Range. Walker Lake, Nevada has a maximum water depth of ~35 m and is situated in a half-graben basin that formed during late Cenozoic transtension, in the Walker Lane tectonic belt. Small-scale climatic variations are preserved in the sediments of this hydrologically closed lake basin. Ten Kullenberg sediment cores (~2 to ~10 m in length), and ~300 km of CHIRP seismic reflection data were collected in Walker Lake to assess late-Quaternary stratigraphic framework and paleoclimate history. Core 4A is one of the longest cores acquired (9.19 m) and contains the oldest recovered sediments. Analyses of total inorganic carbon, total organic carbon, carbon and nitrogen abundances, and carbon stable isotopes from core 4A yield a valuable multi-proxy paleoclimate record. This record documents changes in effective moisture in the eastern Sierra Nevada and western Basin and Range. Sediments range from laminated to massive mud with three tephra deposits 0.5 - 4 cm thick. Total percentage of calcium carbonate, ranging from 3 to 35%, shows oscillations we interpret to be millennial forcings. The average C/N ratio of core 4A is 7.71 (2.5 - 11.3 range), and the stable carbon isotope measurements range from -21.0 to -25.3‰, and average -23.8‰. At ~3.7 m depth a basin-wide angular unconformity is observed in the seismic data and is also reflected in the geochemical data. An estimated age of this surface, 2000-2500 ka, is consistent with previous interpretations of partial diversion of the Walker River into the Carson sink. A ?13Corganic excursion, -25 to -20.8‰, occurs at the depth of the unconformity. We interpret this to be a result of enhanced deposition of aquatic organic matter during the Walker Lake drawdown. From 3.7 to 7.5 m depth, the carbon and nitrogen abundances and isotopes are surprisingly consistent down core and may be the result of protracted stability. Below 7.5 m depth the carbon and nitrogen abundances decrease, as do %CaCO3 and ?13Corganic values. These signatures may reflect past connectivity between Walker Lake and other Lahontan sub-basins. AMS radiocarbon analyses are underway, which will help constrain the paleolimnologic history of the basin.

  12. 76 FR 13665 - Arcelor Mittal, Formerly Known as Mittal Steel Walker Wire, a Subsidiary of Arcelor Mittal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-14

    ...DEPARTMENT OF LABOR Employment and Training Administration [TA-W-71,694] Arcelor Mittal, Formerly Known as Mittal Steel Walker Wire, a Subsidiary of Arcelor Mittal--Montreal, Including On-Site Leased Workers From Leasing Systems,...

  13. Life table studies of rachiplusia nu (guenée) and chrysodeixis (= pseudoplusia) includens (Walker) (lepidoptera: noctuidae) on artificial diet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rachiplusia nu (Guenée) and Chrysodeixis (= Pseudoplusia) includens (Walker) (Lepidoptera: Noctuidae) are two economically important species in soybean in northern Argentina. Life cycle, reproductive and population parameters of R. nu and C. includens reared on artificial diet were determined under ...

  14. March 2007 Safety Meeting Minutes Members Present; Randy Walker, Dave Johnson, Hollis Lundeen Brian Parker and Vlada

    E-print Network

    March 2007 Safety Meeting Minutes Members Present; Randy Walker, Dave Johnson, Hollis Lundeen Brian they are not in a car. Tsunami danger was mentioned as the compelling reason for the addition of a button

  15. Osseous and intestinal compartments in the humoral hypercalcemia of malignancy associated to Walker 256 tumor in rats.

    PubMed

    Torres, R; de la Piedra, C; Rapado, A

    1993-01-01

    The objective of the present work has been to study some aspects of bone and intestinal compartments in rats with Walker 256 carcinosarcoma, an experimental model of humoral hypercalcemia of malignancy (HHM). The results have been compared to those obtained in control animals and, also, to those obtained in Yoshida sarcoma-bearing rats, which were used as tumoral controls without hypercalcemia. Urinary hydroxyproline/creatinine ratio (OHProl/creat) is increased, in both Walker 256 and Yoshida tumor-bearing animals, showing the nonspecifity of this bone marker. However, serum tartrate-resistant acid phosphatase (TRAP) levels are increased in Walker 256 tumor-bearing animals, but they are normal in Yoshida tumor-bearing animals, indicating that TRAP is a better index of bone resorption than OHProl/creat in the HHM syndrome. The decrease of bone calcium content in Walker 256 tumor-bearing rats, not shown by Yoshida-bearing rats, also reflects an increased bone resorption due to HHM. Serum and bone osteocalcin levels are similar in control, Walker 256 and Yoshida tumor-bearing rats, but we observed a decrease in serum alkaline phosphatase levels in Walker 256 and Yoshida tumor-bearing animals, which could also be a nonspecific tumor effect, due to the presence of the neoplasia. Our results support the convenience of the employment of a nonhypercalcemic tumor group as control in the HHM study, in addition to the healthy controls. We have also observed higher 1,25-dihydroxyvitamin D serum levels in Walker 256 tumor-bearing rats than in control and Yoshida tumor-bearing rats. On the other hand, we have found normal levels in the fractional rate of intestinal calcium absorption in Walker-256 tumor-bearing rats, in spite of their high calcium levels, and a significant decrease of this parameter in Yoshida sarcoma-bearing animals. These results support the concomitant contribution of intestinal compartment to hypercalcemia, in the experimental model of HHM studied. PMID:8451038

  16. Robertson-Walker fluid sources endowed with rotation characterised by quadratic terms in angular velocity parameter

    E-print Network

    R J Wiltshire

    2003-02-12

    Einstein's equations for a Robertson-Walker fluid source endowed with rotation Einstein's equations for a Robertson-Walker fluid source endowed with rotation are presented upto and including quadratic terms in angular velocity parameter. A family of analytic solutions are obtained for the case in which the source angular velocity is purely time-dependent. A subclass of solutions is presented which merge smoothly to homogeneous rotating and non-rotating central sources. The particular solution for dust endowed with rotation is presented. In all cases explicit expressions, depending sinusoidally on polar angle, are given for the density and internal supporting pressure of the rotating source. In addition to the non-zero axial velocity of the fluid particles it is shown that there is also a radial component of velocity which vanishes only at the poles. The velocity four-vector has a zero component between poles.

  17. Fast random walker with priors using precomputation for interactive medical image segmentation.

    PubMed

    Andrews, Shawn; Hamarneh, Ghassan; Saad, Ahmed

    2010-01-01

    Updating segmentation results in real-time based on repeated user input is a reliable way to guarantee accuracy, paramount in medical imaging applications, while making efficient use of an expert's time. The random walker algorithm with priors is a robust method able to find a globally optimal probabilistic segmentation with an intuitive method for user input. However, like many other segmentation algorithms, it can be too slow for real-time user interaction. We propose a speedup to this popular algorithm based on offline precomputation, taking advantage of the time images are stored on servers prior to an analysis session. Our results demonstrate the benefits of our approach. For example, the segmentations found by the original random walker and by our new precomputation method for a given 3D image have a Dice's similarity coefficient of 0.975, yet our method runs in 1/25th of the time. PMID:20879377

  18. Sedimentary biomarker and isotopic indicators of the paleoclimatic history of the Walker Lake basin, western Nevada

    USGS Publications Warehouse

    Meyers, P.A.; Benson, L.V.

    1988-01-01

    Walker Lake, a terminal saline lake in western Nevada, has experienced major fluctuations in its water level due to changes in the regional climate during Quaternary times. As part of a paleo-climatological study of western Nevada, we have investigated organic matter ??13C and C/N values and lipid biomarker contents of sediments deposited at various periods over the past 150 thousand years of lake history. Surficial sediments from two cross-lake transects contain mostly lake-derived organic matter. Diagenetic losses of organic matter are evident in deeper sediments, and the proportion of aquatic and terrigenous organic materials changes in response to variations in preservational factors. Source identification of organic matter is complicated by the probability that Walker Lake has experienced desiccation at various times in its history which impacts the degree of preservation of organic substances. ?? 1988.

  19. Design and control of a two-wheeled robotic walker for balance enhancement.

    PubMed

    da Silva, Airton R; Sup, Frank

    2013-06-01

    This paper presents the preliminary design results and control strategy of a two-wheeled inverted pendulum (TWIP) robotic walker for assisting mobility-impaired users with balance and stability. A conceptual model of the vehicle is developed and used to illustrate the purpose of this study. Motor dynamics is considered and the linearized equations of motion for the system are derived using Newtonian mechanics. In order to eliminate the effects of loop interaction and impose the desired dynamics on the system, a decoupling control scheme was implemented. Upright stabilization of the robotic walker is achieved using linear quadratic regulator (LQR) control. Improved disturbance rejection is achieved through the implementation of a pitch controller. Simulation results demonstrate that a robustly tuned pitch controller can mitigate effect of disturbance on the linear displacement of the vehicle by as much as 74%. PMID:24187265

  20. Finite difference method to find period-one gait cycles of simple passive walkers

    NASA Astrophysics Data System (ADS)

    Dardel, Morteza; Safartoobi, Masoumeh; Pashaei, Mohammad Hadi; Ghasemi, Mohammad Hassan; Navaei, Mostafa Kazemi

    2015-01-01

    Passive dynamic walking refers to a class of bipedal robots that can walk down an incline with no actuation or control input. These bipeds are sensitive to initial conditions due to their style of walking. According to small basin of attraction of passive limit cycles, it is important to start with an initial condition in the basin of attraction of stable walking (limit cycle). This paper presents a study of the simplest passive walker with point and curved feet. A new approach is proposed to find proper initial conditions for a pair of stable and unstable period-one gait limit cycles. This methodology is based on finite difference method which can solve the nonlinear differential equations of motion on a discrete time. Also, to investigate the physical configurations of the walkers and the environmental influence such as the slope angle, the parameter analysis is applied. Numerical simulations reveal the performance of the presented method in finding two stable and unstable gait patterns.

  1. Network formed by movements of random walkers on a Bethe lattice

    NASA Astrophysics Data System (ADS)

    Ikeda, Nobutoshi

    2014-03-01

    We investigate a stochastic model of network formation where short-cut edges are assumed to be created between vertices in traces of random walkers. The network initially starts from a tree-like structure (Bethe lattice) with a finite number of shells, and develops into a complex network with many circuits generated by the movement of random walkers. We show that the resulting network has a power-law in the degree distribution with an exponent smaller than 2, and demonstrate the robustness against attacks on hubs in the networks. While scale-free networks without a degree correlation are usually vulnerable to attacks on its hubs, the robustness of the network connectivity in this model comes from a self-similar structure of the network. It is interesting that a simple stochastic process like random walks can cause various structures widely seen in real networks on tree-like graphs which play an important role in the graph theory.

  2. Sex differences in moral reasoning: response to Walker's (1984) conclusion that there are none.

    PubMed

    Baumrind, D

    1986-04-01

    Data from the Family Socialization and Developmental Competence Project are used to probe Walker's conclusion that there are no sex differences in moral reasoning. Ordinal and nominal nonparametric statistics result in a complex but theoretically meaningful network of relationships among sex, educational level, and Kohlberg stage score level, with the presence and direction of sex differences in stage score level dependent on educational level. The effects on stage score level of educational level and working status are also shown to differ for men and women. Reasons are considered for not accepting Walker's dismissal of studies that use (a) a pre-1983 scoring manual, or (b) fail to control for education. The problems presented to Kohlberg's theory by the significant relationship between educational and stage score levels in the general population are discussed, particularly as these apply to the postconventional level of moral reasoning. PMID:3956321

  3. Hadronic Matter in the Robertson-Walker Metric and the Early Universe

    E-print Network

    Cunha, Ivan E

    2015-01-01

    In this work, the Friedman equations for hadronic matter in the Robertson-Walker metric in the early Universe are obtained. We consider the hadronic phase, formed after the hadronization of the quark-gluon plasma, that means times from 10^{-6}s to 1s. The set of equations is derived and the behavior of the system is studied considering one approximate analytical solution.

  4. Hadronic Matter in the Robertson-Walker Metric and the Early Universe

    E-print Network

    Ivan E. Cunha; Celso C. Barros Jr

    2015-05-20

    In this work, the Friedman equations for hadronic matter in the Robertson-Walker metric in the early Universe are obtained. We consider the hadronic phase, formed after the hadronization of the quark-gluon plasma, that means times from 10^{-6}s to 1s. The set of equations is derived and the behavior of the system is studied considering one approximate analytical solution.

  5. Survey of undesirable behaviors displayed by potential guide dogs with puppy walkers

    Microsoft Academic Search

    Angelo Gazzano; Chiara Mariti; Claudio Sighieri; Michele Ducci; Carlo Ciceroni; Elizabeth Anne McBride

    2008-01-01

    This research aimed to identify the frequency and type of undesirable behaviors observed by guide dog puppy walkers and management strategies used by them during the puppy-walking period.All members of 36 puppy-walking families (N = 96), recruited from the National School of Guide Dogs for Blind People in Florence (Italy), completed an 80-item questionnaire. This sampling represented homes caring for

  6. Nonintegrability of density perturbations in the Friedmann-Robertson-Walker universe

    NASA Astrophysics Data System (ADS)

    Stachowiak, Tomasz; Szyd?owski, Marek; Maciejewski, Andrzej J.

    2006-03-01

    We investigate the evolution equation of linear density perturbations in the Friedmann-Robertson-Walker universe with matter, radiation and the cosmological constant. The concept of solvability by quadratures is defined and used to prove that there are no "closed form" solutions except for the known Chernin, Heath, Meszaros and simple degenerate ones. The analysis is performed applying Kovacic's algorithm. The possibility of the existence of other, more general solutions involving special functions is also investigated.

  7. The Friedmann-Lemaitre-Robertson-Walker Big Bang singularities are well behaved

    E-print Network

    Ovidiu-Cristinel Stoica

    2015-06-02

    We show that the Big Bang singularity of the Friedmann-Lemaitre-Robertson-Walker model does not raise major problems to General Relativity. We prove a theorem showing that the Einstein equation can be written in a non-singular form, which allows the extension of the spacetime before the Big Bang. The physical interpretation of the fields used is discussed. These results follow from our research on singular semi-Riemannian geometry and singular General Relativity.

  8. Women in History--Madame C. J. Walker 1867-1919

    ERIC Educational Resources Information Center

    Huber, Germaine W.

    2009-01-01

    This article profiles Madame C. J. Walker. Sarah Breedlove was born on December 23, 1867, the fifth of six children of Owen and Minerva Breedlove. Sarah was the first of the Breedlove children to be born after the end of slavery. Her parents died when she was six or seven years of age. At age fourteen she married Moses McWilliams, who also died in…

  9. The Robertson-Walker Metric in a Pseudo-Complex General Relativity

    E-print Network

    Peter O. Hess; Leila Maghlaoui; Walter Greiner

    2010-01-28

    We investigate the consequences of the pseudo-complex General Relativity within a pseudo-complexified Roberston-Walker metric. A contribution to the energy-momentum tensor arises, which corresponds to a dark energy and may change with the radius of the universe, i.e., time. Only when the Hubble function $H$ does not change in time, the solution is consistent with a constant $\\Lambda$.

  10. Mary B. Walker, M.D. and the pioneering use of prostigmin to treat myasthenia gravis

    Microsoft Academic Search

    ARTHUR H. KEENEYJ; Virginia T. Keeney

    1997-01-01

    In an era when women were not admitted to the University of Edinburgh and when England's first female physician (Elizabeth\\u000a Garrett Anderson, 1836–1917) had to venture to Paris, France, to earn her M.D. in 1870, the career of Mary Broadfoot Walker\\u000a (Figure 1) (1888–1974) stands out for truly remarkable achievement. She is credited with making the most significant discovery\\u000a in

  11. Mary B. Walker, M.D. and the pioneering use of prostigmin to treat myasthenia gravis.

    PubMed

    Keeney, A H; Keeney, V T

    1997-01-01

    In an era when women were not admitted to the University of Edinburgh and when England's first female physician (Elizabeth Garrett Anderson, 1836-1917) had to venture to Paris, France, to earn her M.D. in 1870, the career of Mary Broadfoot Walker (Figure 1) (1988-1974) stands out for truly remarkable achievement. She is credited with making the most significant discovery in medical therapeutic within the British empire. PMID:9476610

  12. Paleomagnetic Data Bearing on the Eastern and Southern Boundaries of the Walker Lane Belt Transfer System

    Microsoft Academic Search

    J. S. Grow; J. W. Geissman; J. S. Oldow

    2007-01-01

    In west-central Nevada, a transfer zone, which initiated in the mid-Miocene, presently links, via the Mina Deflection, right-lateral faults of the Eastern California Shear Zone to the south and the Central Nevada Seismic Belt and Walker Lane to the north. This transfer zone, the early inception of which is characterized by moderate (20-30°) clockwise crustal rotations previously identified (e.g., Candelaria

  13. Can intermittent long-range jumps of a random walker compensate for lethargy?

    NASA Astrophysics Data System (ADS)

    Bologna, Mauro; Ahat, Yasin; West, Bruce J.; Grigolini, Paolo

    2011-04-01

    We study the dynamics of a lazy random walker who is inactive for extended times and tries to make up for her laziness with very large jumps. She remains in a condition of rest for a time ? derived from a waiting-time distribution \\psi (\\tau )\\propto 1/\\tau ^{\\mu _{W}}, with ?W < 2, thereby making jumps only from time to time from a position x to a position x' of a one-dimensional path. However, when the random walker jumps, she moves by quantities l = |x - x'| derived randomly from a distribution \\pi (l)\\propto 1/l^{\\mu _{\\xi }}, with ?? > 1. The most convenient choice to make up for the random walker laziness would be to select ?? < 3, which in the ordinary case ?W > 2 would produce Lévy flights with scaling ? = 1/(?? - 1) and consequently super-diffusion. According to the Sparre Andersen theorem, the distribution density of the first times to go from xA to xB > xA has the inverse power law form f(t)\\propto \\frac{1}{t^{\\mu _{_{FPT}}}} with ?FPT = ?SA = 1.5. We find the surprising result that there exists a region of the phase space (??, ?W) with ?W < 2, where ?FPT > ?SA and the lazy walker compensates for her laziness. There also exists an extended region breaking the Sparre Andersen theorem, where the lazy runner cannot compensate for her laziness. We make conjectures concerning the possible relevance of this mathematical prediction, supported by numerical calculations, for the problem of animal foraging.

  14. Semisynthesis and insecticidal activity of arylmethylamine derivatives of the neolignan honokiol against Mythimna separata Walker.

    PubMed

    Yang, Chun; Zhi, Xiaoyan; Xu, Hui

    2015-03-01

    A series of novel arylmethylamine derivatives of honokiol (5a-m) was prepared. Their insecticidal activity was tested against the pre-third-instar larvae of the oriental armyworm (Mythimna separata Walker), a typical lepidopteran pest. Compounds 5a, 5b, 5e, 5h, and 5k exhibited insecticidal activity equal to, or higher than, that of the positive control toosendanin. PMID:26023846

  15. A coupled theory of tropical climatology: Warm pool, cold tongue, and Walker circulation

    SciTech Connect

    Zhengyu Liu; Boyin Huang [Univ. of Wisconsin, Madison, WI (United States)

    1997-07-01

    Based on results from analytic and general circulation models, the authors propose a theory for the coupled warm pool, cold tongue, and Walker circulation system. The intensity of the coupled system is determined by the coupling strength, the local equilibrium time, and latitudinal differential heating. Most importantly, this intensity is strongly regulated in the coupled system, with a saturation level that can be reached at a modest coupling strength. The saturation west-east sea surface temperature difference (and the associated Walker circulation) corresponds to about one-quarter of the latitudinal differential equilibrium temperature. This regulation is caused primarily by the decoupling of the SST gradient from a strong ocean current. The author`s estimate suggests that the present Pacific is near the saturation state. Furthermore, the much weaker Walker circulation system in the Atlantic Ocean is interpreted as being the result of the influence of the adjacent land, which is able to extend into the entire Atlantic to change the zonal distribution of the trade wind. The theory is also applied to understand the tropical climatology in coupled GCM simulations, in the Last Glacial Maximum climate, and in the global warming climate, as well as in the regulation of the tropical sea surface temperature. 41 refs., 15 figs.

  16. Quantifying Walker River stream temperature variability using distributed temperature sensing data

    NASA Astrophysics Data System (ADS)

    Beck, A. J.; Null, S. E.

    2014-12-01

    Nevada's Walker River historically supported Lahontan cutthroat trout (Oncorhynchus clarki henshawi), although today Lahontan cutthroat trout are listed as a federally threatened species and limited to isolated headwater reaches. Much of the lower Walker River is impaired for native aquatic species because of elevated stream temperatures and nutrients, and low streamflow and dissolved oxygen levels. We deployed a 1 kilometer single-ended fiber-optic Raman spectra distributed temperature sensing (DTS) cable in the Wabuska drain outlet and surrounding Walker River for one week in June 2014 to improve fine-scale understanding of stream temperatures. These data identify and quantify thermal variability of micro-habitat that standard temperature monitoring and modeling do not capture. Results indicate stream temperatures exceeded 26°C and a return flow channel exhibited greater thermal variability with both warmer daytime temperatures and cooler nighttime temperatures - possibly providing more complex thermal habitat during some flow conditions. Fine-scale DTS data complement ongoing stream temperature modeling by bounding thermal variability within model reaches that are 250 m long and where stream temperature is assumed to be well-mixed within each reach.

  17. Sequence walkers: a graphical method to display how binding proteins interact with DNA or RNA sequences.

    PubMed Central

    Schneider, T D

    1997-01-01

    A graphical method is presented for displaying how binding proteins and other macromolecules interact with individual bases of nucleotide sequences. Characters representing the sequence are either oriented normally and placed above a line indicating favorable contact, or upside-down and placed below the line indicating unfavorable contact. The positive or negative height of each letter shows the contribution of that base to the average sequence conservation of the binding site, as represented by a sequence logo. These sequence 'walkers' can be stepped along raw sequence data to visually search for binding sites. Many walkers, for the same or different proteins, can be simultaneously placed next to a sequence to create a quantitative map of a complex genetic region. One can alter the sequence to quantitatively engineer binding sites. Database anomalies can be visualized by placing a walker at the recorded positions of a binding molecule and by comparing this to locations found by scanning the nearby sequences. The sequence can also be altered to predict whether a change is a polymorphism or a mutation for the recognizer being modeled. PMID:9336476

  18. Optimal search strategies of space-time coupled random walkers with finite lifetimes

    NASA Astrophysics Data System (ADS)

    Campos, D.; Abad, E.; Méndez, V.; Yuste, S. B.; Lindenberg, K.

    2015-05-01

    We present a simple paradigm for detection of an immobile target by a space-time coupled random walker with a finite lifetime. The motion of the walker is characterized by linear displacements at a fixed speed and exponentially distributed duration, interrupted by random changes in the direction of motion and resumption of motion in the new direction with the same speed. We call these walkers "mortal creepers." A mortal creeper may die at any time during its motion according to an exponential decay law characterized by a finite mean death rate ?m. While still alive, the creeper has a finite mean frequency ? of change of the direction of motion. In particular, we consider the efficiency of the target search process, characterized by the probability that the creeper will eventually detect the target. Analytic results confirmed by numerical results show that there is an ?m-dependent optimal frequency ? =?opt that maximizes the probability of eventual target detection. We work primarily in one-dimensional (d =1 ) domains and examine the role of initial conditions and of finite domain sizes. Numerical results in d =2 domains confirm the existence of an optimal frequency of change of direction, thereby suggesting that the observed effects are robust to changes in dimensionality. In the d =1 case, explicit expressions for the probability of target detection in the long time limit are given. In the case of an infinite domain, we compute the detection probability for arbitrary times and study its early- and late-time behavior. We further consider the survival probability of the target in the presence of many independent creepers beginning their motion at the same location and at the same time. We also consider a version of the standard "target problem" in which many creepers start at random locations at the same time.

  19. The average number of distinct sites visited by a random walker on random graphs

    E-print Network

    De Bacco, Caterina; Sollich, Peter

    2015-01-01

    We study the linear large $n$ behavior of the average number of distinct sites $S(n)$ visited by a random walker after $n$ steps on a large random graph. An expression for the graph topology dependent prefactor $B$ in $S(n) = Bn$ is proposed. We use generating function techniques to relate this prefactor to the graph adjacency matrix and then devise message-passing equations to calculate its value. Numerical simulations are performed to evaluate the agreement between the message passing predictions and random walk simulations on random graphs. Scaling with system size and average graph connectivity are also analysed.

  20. Ultrasonographic appearance of Dandy Walker-like Syndrome in a Boston Terrier.

    PubMed

    Noureddine, Clarissa; Harder, Rebecca; Olby, Natasha J; Spaulding, Kathy; Brown, Talmage

    2004-01-01

    Congenital cerebellar disorders can be caused by in utero or neonatal infections, genetic aberrations causing malformations, and neurodegenerative processes. Most congenital cerebellar disorders are diagnosed definitively with histopathology. However, antemortem diagnosis of cerebellar malformations can be made by imaging the brain. This paper describes the antemortem appearance of a congenital cerebellar malformation in a Boston Terrier puppy on ultrasound images. This appearance was compared with the postmortem findings that were comparable to Dandy Walker Syndrome in humans. A previous report of this syndrome in Boston Terriers suggests the problem may be inherited in this breed. PMID:15373261

  1. Brownian Motion in Robertson-Walker Space-Times from electromagnetic Vacuum Fluctuations

    E-print Network

    Carlos H. G. Bessa; Valdir B. Bezerra; L. H. Ford

    2008-04-08

    We consider classical particles coupled to the quantized electromagnetic field in the background of a spatially flat Robertson-Walker universe. We find that these particles typically undergo Brownian motion and acquire a non-zero mean squared velocity which depends upon the scale factor of the universe. This Brownian motion can be interpreted as due to non-cancellation of anti-correlated vacuum fluctuations in the time dependent background space-time. We consider several types of coupling to the electromagnetic field, including particles with net electric charge, a magnetic dipole moment, and electric polarizability. We also investigate several different model scale factors.

  2. Reaction kinetics on fractals: Random-walker simulations and excition experiments

    NASA Astrophysics Data System (ADS)

    Kopelman, R.; Klymko, P. W.; Newhouse, J. S.; Anacker, L. W.

    1984-03-01

    Both computer simulations and laboratory experiments on binary reactions of random walkers on fractal spaces bear out a recent conjecture: The time development of the reaction is dominated by the intrinsic fractal (fracton, spectral) dimension. For the Sierpinski gasket the effective spectral dimension for reactions is d's=1.38 (actual spectral dimension ds=1.365). For the percolating cluster (60%, square lattice) d's=1.34 (ds=1.333). From the exciton percolation laboratory experiments d's=1.5, based on triplet-triplet annihilation in naphthalene isotopic mixed crystals at 2 K.

  3. A New Scale-Dependent Cosmology with the Generalized Robertson--Walker Metric and Einstein Equation

    E-print Network

    C. W. Kim; A. Sinibaldi; J. Song

    1995-01-25

    Based on the observed increase of $\\Omega _0$ as a function of cosmic scale, the Robertson--Walker metric and the Einstein equation are generalized so that $ \\Omega_0$, $H_0$, and the age of the Universe, $t_0$, all become functions of cosmic scales at which we observe them. The calculated local (within our galaxy) age of the Universe is about 18 Gyr, consistent with the ages of the oldest stars and globular clusters in our galaxy, while the ages at distant scales are shorter than the local age, solving the age puzzle. It is also shown that $H_0$ increases as scale increases, qualitatively consistent with the recent observations.

  4. Conformally invariant formalism for the electromagnetic field with currents in Robertson-Walker spaces

    NASA Astrophysics Data System (ADS)

    Huguet, E.; Renaud, J.

    2013-02-01

    We show that the Laplace-Beltrami equation ?6a = j in ({R}^6,? ), ? ? diag(+ - - - - +), leads under very moderate assumptions to both the Maxwell equations and the conformal Eastwood-Singer gauge condition on conformally flat spaces including the spaces with a Robertson-Walker metric. This result is obtained through a geometric formalism which gives, as byproduct, simplified calculations. In particular, we build an atlas for all the conformally flat spaces considered which allows us to fully exploit the Weyl rescalling to Minkowski space.

  5. Central diabetes insipidus, central hypothyroidism, renal tubular acidosis and dandy-walker syndrome: new associations.

    PubMed

    Alafif, M M; Aljaid, S S; Al-Agha, A E

    2015-01-01

    Dandy-Walker syndrome (DWS) is a rare brain malformation involving the cerebellum, and the fluid filled spaces around it, usually detected during the antenatal period or the early infancy. Clinically, it is characterized by mental retardation, developmental delay as well as cerebellar ataxia. It has been frequently associated with other conditions such as congenital heart diseases, primary hypothyroidism, and other disorders of the central nervous, gastrointestinal, genitourinary, and orthopedic systems. In this report, we describe a 3-month-old Saudi boy with the rare association of DWS with central diabetes insipidus, congenital central hypothyroidism, and type-2 renal tubular acidosis. PMID:25861538

  6. Synthesis of benzoxazole derivatives of honokiol as insecticidal agents against Mythimna separata Walker.

    PubMed

    Yang, Chun; Zhi, Xiaoyan; Xu, Hui

    2015-05-15

    A series of novel benzoxazole compounds derived from a naturally occurring neolignan honokiol were prepared. Their insecticidal activity was tested against the pre-third-instar larvae of oriental armyworm (Mythimna separata Walker) in vivo. Most of the tested derivatives exhibited more potential insecticidal activity than their precursor honokiol at the concentration of 1mg/mL. Especially compound 6e, containing 4-acetyloxyphenyl groups at the C8 and C8' positions, displayed the most potent insecticidal activity with the final mortality rate of 62.1%. PMID:25872985

  7. Dandy-Walker malformation masking the molar tooth sign: an illustrative case with magnetic resonance imaging follow-up.

    PubMed

    Sartori, Stefano; Ludwig, Kathrin; Fortuna, Manuela; Marzocchi, Cinzia; Calderone, Milena; Toldo, Irene; Salviati, Leonardo; Laverda, Anna Maria; Tenconi, Romano

    2010-11-01

    Joubert syndrome is a disorder characterized by ataxia, developmental delay, oculomotor anomalies, and breathing irregularities, with cerebellar vermian and midbrain dysgenesis. The molar tooth sign, reflecting the midbrain dysgenesis of Joubert syndrome, is the neuroradiological hallmark and is an essential sign in the identification of this condition. Variable vermian agenesis, an expanded fourth ventricle, and a large posterior cranial fossa with a normal brainstem are typical of Dandy-Walker malformation. The authors report a case in which a Dandy-Walker malformation coexisted with Joubert syndrome, but initially prevented the ''molar tooth sign'' from being recognized because of an important cystic dilatation of the fourth ventricle. In this article, they discuss the importance of the re-examination of brain magnetic resonance features after decompression of the posterior cranial fossa in a patient with Dandy-Walker malformation and additional clinical neurological or systemic abnormalities typical of Joubert syndrome, to not miss the correct diagnosis. PMID:20823032

  8. Regional patterns of surface wind change over the tropical Indo-Pacific: Evidence of the Walker circulation slowdown

    NASA Astrophysics Data System (ADS)

    Tokinaga, H.; Xie, S.; Timmermann, A.; McGregor, S.; Ogata, T.; Kubota, H.; Okumura, Y.

    2012-12-01

    A strong linkage between changes in the Walker circulation and tropical sea surface temperature (SST) is evident in satellite observations. For instance, a strengthening of the Walker circulation is observed by satellite wind measurements in recent decades, accompanied by intensified zonal SST and sea level height gradients. On the other hand, climate models predict that the Walker circulation slows down in response to global warming through hydrological cycle changes. We investigate these mechanisms for the observed Walker circulation changes over the last six decades, with a focus on physical consistency among surface wind, cloud, sea level pressure (SLP), subsurface ocean temperature, and SST. Our bias-corrected surface wind dataset displays westerly trends over the western tropical Pacific and easterly trends over the tropical Indian Ocean, indicative of a slowdown of the Walker circulation. This pattern of wind change is consistent with that of observed SLP change showing positive trends over the Maritime Continent and negative trends over the central equatorial Pacific. Suppressed moisture convergence over the Maritime Continent is largely due to surface wind changes, contributing to observed decreases in marine cloudiness and land precipitation there. Furthermore, observed ocean mixed layer temperatures indicate a reduction in zonal contrast in the tropical Indo-Pacific characterized by larger warming in the tropical eastern Pacific and western Indian Ocean than in the tropical western Pacific and eastern Indian Ocean. Similar changes are successfully simulated by an ocean general circulation model forced with the bias-corrected wind stress. Whereas results from major SST reconstructions show large uncertainty in zonal gradient in the tropical Indo-Pacific, both bucket-sampled SSTs and nighttime marine air temperatures show a weakening of the zonal gradient consistent with the subsurface temperature changes. All these findings from independent observations provide robust evidence for ocean-atmosphere coupling associated with the reduction in the Walker circulation over the last six decades.

  9. Mutations in extracellular matrix genes NID1 and LAMC1 cause autosomal dominant Dandy-Walker malformation and occipital cephaloceles

    PubMed Central

    Darbro, Benjamin W.; Mahajan, Vinit B.; Gakhar, Lokesh; Skeie, Jessica M.; Campbell, Elizabeth; Wu, Shu; Bing, Xinyu; Millen, Kathleen J.; Dobyns, William B.; Kessler, John A.; Jalali, Ali; Cremer, James; Segre, Alberto; Manak, J. Robert; Aldinger, Kimerbly A.; Suzuki, Satoshi; Natsume, Nagato; Ono, Maya; Hai, Huynh Dai; Viet, Le Thi; Loddo, Sara; Valente, Enza M.; Bernardini, Laura; Ghonge, Nitin; Ferguson, Polly J.; Bassuk, Alexander G.

    2013-01-01

    We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation and occipital cephaloceles (ADDWOC) and detected a mutation in the extracellular matrix protein encoding gene NID1. In a second family, protein interaction network analysis identified a mutation in LAMC1, which encodes a NID1 binding partner. Structural modeling the NID1-LAMC1 complex demonstrated that each mutation disrupts the interaction. These findings implicate the extracellular matrix in the pathogenesis of Dandy-Walker spectrum disorders. PMID:23674478

  10. Analog Landau-He-McKellar-Wilkens quantization due to noninertial effects of the Fermi-Walker reference frame

    SciTech Connect

    Bakke, Knut [Department of Physics, University of Oxford, Clarendon Laboratory, Oxford OX1 3PU (United Kingdom)

    2010-05-15

    We will show that when a neutral particle with permanent electric dipole moment interacts with a specific field configuration when the local reference frames of the observers are Fermi-Walker transported, the Landau quantization analog to the He-McKellar-Wilkens setup arises in the nonrelativistic quantum dynamics of the neutral particle due the noninertial effects of the Fermi-Walker reference frame. We show that the noninertial effects do not break the infinity degeneracy of the energy levels, but in this case, the cyclotron frequency depends on the angular velocity.

  11. Changes in Soil Carbon and Nitrogen in Forests of Walker Branch Watershed 1972-2004

    SciTech Connect

    Todd Jr, Donald E [ORNL; Johnson, Dale W. [University of Nevada, Reno; Trettin, Carl [USDA Forest Service

    2007-01-01

    Changes in soil C and N concentrations and contents in four samplings during a 32-yr period on Walker Branch watershed in Tennessee were determined and compared with previously measured C and N fluxes and with changes in ecosystem C and N pools during this period. Soils showed significant increases in C and N concentrations in surface horizons from 1972 to 2004, and most of this increase occurred between 1972 and 1982. A previously observed decline in soil C and N contents between 1982 and 1993 was reversed in 2004 such that the latter increased to near 1982 values. The changes in soil C content could be approximately accounted for by previously measured litterfall and soil CO{sub 2}-C fluxes. Changes in soil N could not be accounted for by leaching, increments in vegetation, or by laboratory bias, changes during sample storage, or reasonable estimates of field sampling errors. We conclude that, although vegetation C and N pools increased steadily during the sampling period in most cases, changes in soil C and N pools on Walker Branch watershed are highly variable in both space and time, and there has been no unidirectional trend during the time period of this study.

  12. Bobble-head doll syndrome associated with Dandy-Walker syndrome. Case report.

    PubMed

    de Brito Henriques, José Gilberto; Henriques, Karina Santos Wandeck; Filho, Geraldo Pianetti; Fonseca, Luiz Fernando; Cardoso, Francisco; Da Silva, Márcia Cristina

    2007-09-01

    Bobble-head doll syndrome (BHDS) presents in childhood and is usually associated with lesions of the third ventricle. This disorder is characterized by stereotypical head movements of the type "yes-yes" (up and down) at a frequency of 2 to 3 Hz. Rarely, movements of the type "no-no" (side-to-side) are described. There are a few hypotheses to explain the mechanism responsible for BHDS, but its real pathophysiological characteristics are still unknown. The authors describe the case of a child born with hydrocephalus and Dandy-Walker syndrome. A ventriculoperitoneal shunt was implanted in the child because of progressive head enlargement. One year after shunt placement, she began making frequent horizontal head movements of the type "no-no". There were no other signs or symptoms. Imaging studies demonstrated small ventricles and a posterior fossa cyst with no signs of hypertension. The child's growth, development, and head circumference (within the 5th percentile) remained satisfactory. Three aspects of this case were of interest: the association of BHDS with Dandy-Walker syndrome, the rare occurrence of BHDS of the "no-no" type, and the absence of third ventricle dilation. The authors' findings support the hypothesis that cerebellar malformations themselves can PMID:17918536

  13. New perspectives on quaternary faulting in the southern Walker Lane, Nevada and California

    SciTech Connect

    Reheis, M.C.; Noller, J.S.

    1987-12-31

    A preliminary survey of aerial photographs of the southern Walker Lane began in late 1986. The purpose of this survey is to determine the nature and scope of future studies required to ascertain whether the apparent concentration of Quaternary faults in and near the Nevada Test Site is real or is simply a result of the greater effort invested in mapping Quaternary deposits in that area, and determine whether faults in the southern Walker Lane are active and could produce significant earthquakes. The survey is focused on the area extending south from Lone Mountain to Pahrump Valley and east from the Furnace Creek fault zone to an irregular line passing through the Cactus Range and Pahute Mesa. Lineaments and scraps were identified on stereopairs of black-and-white aerial photographs at scales of 1:80,000 or 1:60,000. The lineaments and and scarps were plotted on 1:24,000- and 1:62,500-scale topographic maps using a PG-2 plotter, and were color-coded according to distinctness and occurrence in Quaternary or Tertiary deposits (age assignments based on appearance in aerial photographs and on existing geologic maps). Additional lineaments identified on the topographic maps were also plotted. Areas of particular interest were selected for more detailed study using larger-scale aerial photographs. Most of the lineaments and scraps identified in the survey, although referred to as faults in this paper, have not been checked in the field. 11 refs., 1 fig.

  14. Grain-size data from four cores from Walker Lake, Nevada

    SciTech Connect

    Yount, J.C. [Geological Survey, Reno, NV (USA); Quimby, M.F. [Geological Survey, Menlo Park, CA (USA)

    1990-11-01

    A number of cores, taken from within and near Walker Lake, Nevada are being studied by various investigators in order to evaluate the late-Pleistocene paleoclimate of the west-central Great Basin. In particular, the cores provide records that can be interpreted in terms of past climate and compared to proposed numerical models of the region`s climate. All of these studies are being carried out as part of an evaluation of the regional paleoclimatic setting of a proposed high-level nuclear waste storage facility at Yucca Mountain, Nevada. Changes in past climate often manifest themselves in changes in sedimentary processes or in changes in the volume of sediment transported by those processes. One fundamental sediment property that can be related to depositional processes is grain size. Grain size effects other physical properties of sediment such as porosity and permeability which, in turn, affect the movement and chemistry of fluids. The purposes of this report are: (1) to document procedures of sample preparation and analysis, and (2) to summarize grain-size statistics for 659 samples from Walker Lake cores 84-4, 84-5, 84-8 and 85-2. Plots of mean particle diameter, percent sand, and the ratio of silt to clay are illustrated for various depth intervals within each core. Summary plots of mean grain size, sorting, and skewness parameters allow comparison of textural data between each core. 15 refs., 8 figs., 3 tabs.

  15. Leucine-rich diet supplementation modulates foetal muscle protein metabolism impaired by Walker-256 tumour

    PubMed Central

    2014-01-01

    Background Cancer-cachexia induces a variety of metabolic disorders of protein turnover and is more pronounced when associated with pregnancy. Tumour-bearing pregnant rats have impaired protein balance, which decreases protein synthesis and increases muscle breakdown. Because branched-chain amino acids, especially leucine, stimulate protein synthesis, we investigated the effect of a leucine-rich diet on protein metabolism in the foetal gastrocnemius muscles of tumour-bearing pregnant rats. Methods Foetuses of pregnant rats with or without Walker 256 tumours were divided into six groups. During the 20 days of the experiment, the pregnant groups were fed with either a control diet (C, control rats; W, tumour-bearing rats; Cp, rats pair-fed the same normoprotein-diet as the W group) or with a leucine-rich diet (L, leucine rats; LW, leucine tumour-bearing rats; and Lp, rats pair-fed the same leucine-rich diet as the LW group). After the mothers were sacrificed, the foetal gastrocnemius muscle samples were resected, and the protein synthesis and degradation and tissue chymotrypsin-like, cathepsin and calpain enzyme activities were assayed. The muscle oxidative enzymes (catalase, glutathione-S-transferase and superoxide dismutase), alkaline phosphatase enzyme activities and lipid peroxidation (malondialdehyde) were also measured. Results Tumour growth led to a reduction in foetal weight associated with decreased serum protein, albumin and glucose levels and low haematocrit in the foetuses of the W group, whereas in the LW foetuses, these changes were less pronounced. Muscle protein synthesis (measured by L-[3H]-phenylalanine incorporation) was reduced in the W foetuses but was restored in the LW group. Protein breakdown (as assessed by tyrosine release) was enhanced in the L and W groups, but chymotrypsin-like activity increased only in group W and tended toward an increase in the LW foetuses. The activity of cathepsin H was significantly higher in the W group foetuses, but the proteolytic calcium-dependent pathway showed similar enzyme activity. In parallel, an intense oxidative stress process was observed only in the group W foetuses. Conclusions These data suggested that the proteasomal and lysosomal proteolytic pathways and oxidative stress are likely to participate in the process of foetal muscle catabolism of Walker’s tumour-bearing pregnant rats. The present work shows that foetal muscle can be protected by supplementation with a leucine-rich diet. PMID:24383706

  16. Overnight Therapy? The Role of Sleep in Emotional Brain Processing Matthew P. Walker and Els van der Helm

    E-print Network

    Walker, Matthew P.

    -dependent emotional brain processing. On the basis of the unique neurobiology of sleep, the authors outline a modelOvernight Therapy? The Role of Sleep in Emotional Brain Processing Matthew P. Walker and Els van renaissance has taken place, focusing on the role of sleep in various neurocognitive processes and, most

  17. Wafer-level Spatial and Flush Delay Analysis for IDDQ Estimation Sagar S. Sabade Duncan M. Walker

    E-print Network

    Walker, Duncan M. "Hank"

    Wafer-level Spatial and Flush Delay Analysis for IDDQ Estimation Sagar S. Sabade Duncan M. Walker between IDDQ and a second parameter like speed [16], temperature [17], and die position on a wafer [18 median IDDQ for all chips that passed all tests or failed only IDDQ test at the wafer level and had

  18. "It's Not so Much a Job but a Relationship": A Response to Romer and Walker

    ERIC Educational Resources Information Center

    O'Brien, John

    2013-01-01

    Romer and Walker's "Appreciative Inquiry," which obtained input from 16 capable personal assistants, challenges some influential assumptions about personal assistance and opens a way to think about the demanding work of developing capable and committed personal assistants. Attempts to depersonalize the relationship between people…

  19. Confirmation of the Old World species Phricanthes flexilineana (Walker) in the New World tropics (Lepidoptera: Tortricidae: Phricanthini)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Old World species Phricanthes flexilinena (Walker) is reported from Costa Rica and Panama for the first time, confirming a nearly century-old report that the species occurs in the New World (i.e., Guyana). Two new larval host plants are reported for the species in Costa Rica: Tetracera volubilis...

  20. Lithostratigraphy, magnetostratigraphy, and radiometric dating of the Stanislaus Group, CA, and age of the Little Walker Caldera

    E-print Network

    Busby, Cathy

    /trachydacite) lavas and ignimbrites, provides an important marker for reconstructing the elevation history lavas at ca. 10.4 Ma and (2) ignimbrite eruptions alternating with lesser lava flow eruptions during ca of the present Sierra Nevada crest, whereas the ignimbrite eruptions formed the Little Walker Caldera. Our new

  1. July 7, 2004 Safety Meeting Minutes Present; Thea Smith, Faith Cole, Randy Walker, Sean Matson and Lori Parker

    E-print Network

    a safety and health point of view. It was noted that Ann Byar from NOAA's Safety Division had lab Safety. It is NOAA and OSU policy that they not be worn in the labs. Next month there will be a safety walk throughJuly 7, 2004 Safety Meeting Minutes Present; Thea Smith, Faith Cole, Randy Walker, Sean Matson

  2. Rice white stemborer Scirpophaga innotata (Walker) in southern Mindanao, Philippines. II. Synchrony of planting and natural enemies

    Microsoft Academic Search

    J. A. Litsinger; A. L. Alviola; C. G. Dela Cruz; B. L. Canapi; E. H. Batay-An III; A. T. Barrion

    2006-01-01

    Although the rice white stemborer (WSB) Scirpophaga innotata (Walker) has been an epidemic pest in other locations in the Philippines and Indonesia, its population has remained at chronic pest levels in Koronadal, southern Mindanao, Philippines. Field studies were undertaken to determine the role of egg parasitoids and general predators in suppressing WSB numbers. The results revealed greater mortality levels on

  3. NOMA Investigating the Host-Pathogen Interaction using a Staphyloc SICAL ASPECTS AND EMERGENT BEHAVIORS Genetics of Walker-Wa

    E-print Network

    Knipe, David M.

    BEHAVIORS Genetics of Walker-Wa MIC S-NITROSYLATION OF ENDOTHELIAL NITRIC OXIDE SYNTHASE IN VASC Development and in Regulating Synapt Molecular Development of Corticospinal Motor Neurons ND PRACTICAL a Representation and Algorithms for Biomedical Informatics Applications traints and Solutions Anatomical

  4. Applications of List Decoding to Tracing Traitors Alice Silverberg, Jessica Staddon, Member, IEEEand Judy L. Walker, Member, IEEE

    E-print Network

    Logan, David

    : silver@math.ohio-state.edu. Silverberg would like to thank MSRI, Bell Labs Research Silicon Valley, Xerox of this work was completed while Staddon was employed by Bell Labs Research Silicon Valley. J. Walker of Sudan [19] and were refined in [11]. In list decoding the input is a received word and the output

  5. Water at Hydrophobic Surfaces: When Weaker Is Better Dennis K. Hore, Dave S. Walker, and Geraldine L. Richmond*

    E-print Network

    Richmond, Geraldine L.

    interfaces. Air-water (black), carbon tetrachloride-water (red), chloroform-water (blue), and dichloromethane-waterWater at Hydrophobic Surfaces: When Weaker Is Better Dennis K. Hore, Dave S. Walker,§ and Geraldine, 2007; E-mail: richmond@uoregon.edu The upsurge of interest in the nature of water adjacent

  6. Spin-axis relaxation in spin-exchange collisions of alkali-metal atoms S. Kadlecek and T. Walker

    E-print Network

    Walker, Thad G.

    Spin-axis relaxation in spin-exchange collisions of alkali-metal atoms S. Kadlecek and T. Walker October 2000; published 18 April 2001 We present calculations of spin-relaxation rates of alkali that collisions between alkali-metal atoms rigorously conserve the spin polarization, Bhaskar et al. 7 discovered

  7. BASS' NK GROUPS AND cdh-FIBRANT HOCHSCHILD G. CORTI~NAS, C. HAESEMEYER, MARK E. WALKER, AND C. WEIBEL

    E-print Network

    Weibel, Charles

    BASS' NK GROUPS AND cdh-FIBRANT HOCHSCHILD HOMOLOGY. G. CORTI~NAS, C. HAESEMEYER, MARK E. WALKER and the cohomology of K¨ahler differentials for the cdh topology. We use this to address Bass' question, whether Kn is essentially of finite type over the complex numbers, but negative in general. In 1972, H. Bass posed

  8. Consequences of Selecting Incorrect Hydrologic Parameters When Using the Walker Pond Size and P8 Urban Catchment Models

    Microsoft Academic Search

    John C. Panuska; Joel G. Schilling

    1993-01-01

    The Walker Pond Size Model is a widely used spreadsheet approach to the design of storm water treatment ponds. The user inputs the Soil Conservation Service curve number for the pervious areas and the fraction of impervious area. Input parameters must be correctly determined by the user. One commonly made error is to enter the weighted curve number in place

  9. Plant-growth response to various combinations of mulches and spoil substrates on a Walker County, Alabama, surface coal mine

    Microsoft Academic Search

    E. A. Cross; F. C. Gabrielson; T. H. Hughes

    1982-01-01

    In 1978-1979, Walker County, Alabama, was the site of an experiment designed to assess plant growth and soil erosion. The experiment utilized 6 mulch treatments applied to each of 3 coal surface mine substrates. The mulches (wood fiber, hardwood bark, pine bark, waste compost, paper-slag, and no mulch application) were randomly combined with either A + B horizon soil, shale,

  10. Binding of Formyl Peptides to Walker 256 Carcinosarcoma Ceils and the Chemotactic Response of These Cells1

    Microsoft Academic Search

    David C. Rayner; F. William Orr; Robert P. C. Shiu

    1985-01-01

    N-Formylmethionylleucylphenylalanine (fMLP) induces che- motaxis in leukocytes, the response being mediated by peptide binding to a receptor on the plasma membrane. In tumor cells, this peptide has been reported to induce cellular swelling and chemotaxis in vitro and to enhance the localization of circulating tumor cells in vivo. In the Boyden chamber, we evaluated the migratory responses of Walker carcinosarcoma

  11. Taxonomic study of the genus Assara Walker (Lepidoptera, Pyralidae, Phycitinae) in NE China, with description of a new species.

    PubMed

    Qi, Mu-Jie; Han, Hui-Lin; Park, Bo-Sun; Bae, Yang-Seop

    2014-01-01

    Four species of the genus Assara Walker, 1863 are revised from NE China. Among them, Assara yanbianensis Bae & Qi sp. n. is described as new to science and A. terebrella (Zincken, 1818) is newly recorded from China. A key to the NE Chinese species of the genus Assara with illustrations of adults and genitalia are presented. PMID:24943428

  12. Covariant point-splitting regularization for a scalar quantum field in a Robertson-Walker universe with spatial curvature

    Microsoft Academic Search

    T. S. Bunch; P. C. W. Davies

    1977-01-01

    We evaluate the vacuum stress tensor for a massless scalar quantum field in a general Robertson-Walker background spacetime, and that for a massive field in the special case of the Einstein universe, using covariant point-splitting regularization. A comparison is made with previous partial results of Ford, and Dowker and Critchley. It is shown that the stress tensor expectation value is

  13. Vision-based SLAM and moving objects tracking for the perceptual support of a smart walker platform

    E-print Network

    Argyros, Antonis

    has important implica- tions in robotics. In this work, we investigate how moving object tracking, egoVision-based SLAM and moving objects tracking for the perceptual support of a smart walker platform to the problem parameters make it a valuable component for any robotic platform that moves in a dynamic

  14. Manju Hemakumara, Jetse Kalma, Jeffrey Walker, and Garry Willgoose (2004), Downscaling of low resolution passive microwave soil moisture

    E-print Network

    Walker, Jeff

    2004-01-01

    attributes. Second, the paper reports on downscaling of the low resolution AMSR-E near-surface soil moisture resolution passive microwave soil moisture observations, in Proceedings of the 2nd international CAHMDA soil moisture observations Manju Hemakumara1, Jetse Kalma1, Jeffrey Walker2, and Garry Willgoose3 1

  15. Giantism and its role in the harmful algal bloom species Phaeocystis globosa Walker O. Smith, Jr.a,*

    E-print Network

    Latour, Robert J.

    1 Giantism and its role in the harmful algal bloom species Phaeocystis globosa Walker O. Smith, Jr of Oceanography, Nha Trang, Viet Nam c : Research Center for Harmful Algae and Aquatic Environment, Jinan T _______________________ ________________________________________________________________ Keywords: The cosmopolitan alga Phaeocystis globosa forms large blooms in shallow coastal waters

  16. Giantism and its role in the harmful algal bloom species Phaeocystis globosa Walker O. Smith Jr.a,n

    E-print Network

    Newman, Michael C.

    Giantism and its role in the harmful algal bloom species Phaeocystis globosa Walker O. Smith Jr Research Center for Harmful Algae and Aquatic Environment, Jinan University, Guangzhou, China a r t i c l e alga Phaeocystis globosa forms large blooms in shallow coastal waters off the Viet Nam coast, which

  17. Vacuum polarization of the quantized massive fields in Friedman-Robertson-Walker spacetime

    NASA Astrophysics Data System (ADS)

    Matyjasek, Jerzy; Sadurski, Pawe?; Telecka, Ma?gorzata

    2014-04-01

    The stress-energy tensor of the quantized massive fields in a spatially open, flat, and closed Friedman-Robertson-Walker universe is constructed using the adiabatic regularization (for the scalar field) and the Schwinger-DeWitt approach (for the scalar, spinor, and vector fields). It is shown that the stress-energy tensor calculated in the sixth adiabatic order coincides with the result obtained from the regularized effective action, constructed from the heat kernel coefficient a3. The behavior of the tensor is examined in the power-law cosmological models, and the semiclassical Einstein field equations are solved exactly in a few physically interesting cases, such as the generalized Starobinsky models.

  18. Establishment and characterization of a new cell line of Chilo suppressalis Walker (Lepidoptera: Pyralididae).

    PubMed

    Liu, Guangfu; Xu, Yipeng; Yu, Xiaoping

    2015-03-01

    A new cell line, designated as ZJBIQ-Chsu-I, was initiated from the fat body of larval Chilo suppressalis (Walker) (Lepidoptera: Pyralididae) in TNM-FH insect medium containing 15% fetal bovine serum. The polygonal cells (65.6%) were predominant among various cell types, and the diameter range was from 12.63 to 22.50 ?m. The cell line showed a typical lepidopteran chromosome pattern ranging from 108 to 136 chromosomes in the majority of the cells. The population doubling time (PDT) of the cell line at the 15th passage was 62 h. This cell line was found to be susceptible to Spodoptera exigua nuclear polyhedrosis virus (SeNPV). By the DNA amplification fingerprinting polymerase chain reaction (DAF-PCR) technique, it was confirmed that cell line ZJBIQ-Chsu-I really originated from C. suppressalis. PMID:25381037

  19. An Extension of Friedmann-Robertson-Walker Theory beyond Big Bang

    E-print Network

    Joachim Schroeter

    2009-07-03

    Starting from the classic Friedmann-Robertson-Walker theory with big bang it is shown that the solutions of the field equations can be extended to negative times. Choosing a new cosmic time scale instead of proper time one achieves complete differentiability of the scale factor and of suitable thermodynamic quantities equivalent to pressure and energy density. Then, the singularity of big bang manifests itself only by the vanishing of the scale factor at time zero. Moreover, all solutions of the field equations are defined for all times from -infinity to +infinity. In a separate chapter the horizon structure of the extended theory is studied. Some weak assumptions guarantee that there are no horizons. Hence, the horizon problem in a strict sence disappears. An intensive discussion of the results is given at the end of the paper.

  20. A Review of the Genus Miresa Walker in China (Lepidoptera: Limacodidae)

    PubMed Central

    Wu, Chun-Sheng; Solovyev, Alexey V.

    2011-01-01

    Eight species of the genus Miresa Walker are recognized in China including two new species, M. fangae Wu & Solovyev and M. polargenta Wu & Solovyev, described herein. M. burmensis Hering species is reported for the first time in China. The M. argentifera kwangtungensis Hering, 1931 taxon is raised to full specific status. The lectotypes are designated for the following 5 taxa: M. bracteata Butler, 1880 (?, Natural History Museum, London); M. fulgida Wileman, 1910 (?, Natural History Museum, London); M. bracteata var. orientis Strand, 1915 (?, Rijksmuseum van Natuurlijke Historie, Leiden); M. argentifera kwangtungensis Hering, 1931 (?, Zoologisches Museum der Humboldt Universität zu Berlin) and M. urga Hering, 1933 (?, Zoologisches Museum der Humboldt Universität zu Berlin). The photographs of moths and their genitalia are given, a key to the Chinese species of the genus is provided, and the distributional maps are also given. PMID:21529254

  1. Ascending transaqueductal cystoventriculoperitoneal shunting in Dandy-Walker malformation: technical note.

    PubMed

    Unal, Omer Faruk; Aras, Yavuz; Aydoseli, Aydin; Akcakaya, Mehmet Osman

    2012-01-01

    The optimal treatment for Dandy-Walker malformation is still controversial. Ventriculoperitoneal shunting, cystoperitoneal shunting or combinations are the most common surgical options in the management of this clinical entity. Endoscopic procedures like ventriculocystostomy, 3rd ventriculostomy or endoscopy-assisted shunt surgeries have become the focus of recent publications. We describe a new transcystic endoscopic technique, with the usage of a single ascending transaqueductal shunt catheter with additional holes, whereby both the posterior fossa cyst and supratentorial ventricular compartments are drained effectively. By using this new technique complications associated with combined shunting can be avoided. In addition, by equalizing the pressure within the supra- and infratentorial compartments, the upward or downward herniations associated with single-catheter shunting can be prevented. PMID:23941970

  2. Asymptotic analysis and diffusion limit of the Persistent Turning Walker Model

    E-print Network

    Patrick Cattiaux; Djalil Chafai; Sébastien Motsch

    2009-09-28

    The Persistent Turning Walker Model (PTWM) was introduced by Gautrais et al in Mathematical Biology for the modelling of fish motion. It involves a nonlinear pathwise functional of a non-elliptic hypo-elliptic diffusion. This diffusion solves a kinetic Fokker-Planck equation based on an Ornstein-Uhlenbeck Gaussian process. The long time "diffusive" behavior of this model was recently studied by Degond & Motsch using partial differential equations techniques. This model is however intrinsically probabilistic. In the present paper, we show how the long time diffusive behavior of this model can be essentially recovered and extended by using appropriate tools from stochastic analysis. The approach can be adapted to many other kinetic "probabilistic" models.

  3. Asymptotic analysis and diffusion limit of the Persistent Turning Walker Model

    E-print Network

    Cattiaux, Patrick; Motsch, Sébastien

    2008-01-01

    The Persistent Turning Walker Model (PTWM) was introduced by Gautrais et al in Mathematical Biology for the modelling of fish motion. It involves a nonlinear pathwise functional of a non-elliptic hypo-elliptic diffusion. This diffusion solves a kinetic Fokker-Planck equation based on an Ornstein-Uhlenbeck Gaussian process. The long time "diffusive" behavior of this model was recently studied by Degond & Motsch using partial differential equations techniques. This model is however intrinsically probabilistic. In the present paper, we show how the long time diffusive behavior of this model can be essentially recovered and extended by using appropriate tools from stochastic analysis. The approach can be adapted to many other kinetic "probabilistic" models. Beyond the mathematical results, the aim of this short paper is also to contribute to the diffusion of stochastic techniques in the domain of partial differential equations. Also, the text aims to be very accessible for non probabilists.

  4. Movement strategies and sensory reweighting in tandem stance: differences between trained tightrope walkers and untrained subjects.

    PubMed

    Honegger, F; Tielkens, R J M; Allum, J H J

    2013-12-19

    Does skill with a difficult task, such as tightrope walking, lead to improved balance through altered movement strategies or through altered weighting of sensory inputs? We approached this question by comparing tandem stance (TS) data between seven tightrope walkers and 12 untrained control subjects collected under different sensory conditions. All subjects performed four TS tasks with eyes open or closed, on a normal firm or foam surface (EON, ECN, EOF, ECF); tightrope walkers were also tested on a tightrope (EOR). Head, upper trunk and pelvis angular velocities were measured with gyroscopes in pitch and roll. Power spectral densities (PSDs) ratios, and transfer function gains (TFG) between these body segments were calculated. Center of mass (CoM) excursions and its virtual time to contact a virtual base of support boundary (VTVBS) were also estimated. Gain nonlinearities, in the form of decreased trunk to head and trunk to pelvis PSD ratios and TFGs, were present with increasing sensory task difficulty for both groups. PSD ratios and TFGs were less in trained subjects, though, in absolute terms, trained subjects moved their head, trunk, pelvis and CoM faster than controls, and had decreased VTVBS. Head roll amplitudes were unchanged with task or training, except above 3Hz. CoM amplitude deviations were not less for trained subjects. For the trained subjects, EOR measures were similar to those of ECF. Training standing on a tightrope induces a velocity modification of the same TS movement strategy used by untrained controls. More time is spent exploring the limits of the base of support with an increased use of fast trunk movements to control balance. Our evidence indicates an increased reliance on neck and pelvis proprioceptive inputs. The similarity of TS on foam to that on the tightrope suggests that the foam tasks are useful for effective training of tightrope walking. PMID:24090964

  5. The Silver Peak Volcanic Center: Shoshonitic Volcanism in the Walker Lane, Western Nevada

    NASA Astrophysics Data System (ADS)

    Robinson, P. T.; Zhou, M.; Li, J.; Chen, L.; Ma, C.; Gao, J.

    2012-12-01

    Shoshonitic and high-K volcanism is widespread in the Sierra Nevada and western Nevada. The Silver Peak center, located in the Walker Lane, just east of the White Mountains, lies within the Silver Peak detachment. It consists of a subcircular volcanic complex about 15 km in diameter, with a central caldera. Volcanic activity spanned a period of 1myr from 6.0±0.5 to 4.8±0.6 Ma. The lavas range from trachybasalt to rhyolite and plot in the shoshonite field on the SiO2-K2O diagram. Oxide trends indicate relatively continuous fractionation of a parental basaltic magma. Fractionation took place in a subvolcanic magma chamber, which was periodically injected with new batches of basalt, leading to two major explosive events and resetting the fractionation processes. The first event, which erupted voluminous rhyolite ashflows, resulted in an elliptical caldera 12 by 9 km; the second produced highly feldspar-phyric trachyandesite ashflows and lavas. The most mafic lava is a trachybasalt with about 49 wt% SiO2, 7.5 wt% MgO and 2.5 wt% K2O, which contains olivine phenocrysts of Fo85. Chondrite-normalized REE patterns of the lavas show flat HREE, strong enrichment in LREE (LaN/SmN =3.5-7.7; aver. = 4.7) and variable negative Eu anomalies ranging from .21-.85. In-situ 87Sr/86Sr compositions of plagioclase grains are quite uniform, mostly between 0.7060 and 0.7070, similar to the whole-rock values (0.7061) and indicating little if any crustal contamination. We suggest that the parental magma was derived from a metasomatised mantle source by small degrees of partial melting. It was mixed periodically with new pulses of mafic magma and underwent fractional crystallization to produce the observed range of compositions. . Melting was probably triggered by transtensional deformation in the Walker Lane.

  6. Organic geochemistry and brine composition in Great Salt, Mono, and Walker Lakes

    NASA Astrophysics Data System (ADS)

    Domagalski, Joseph L.; Orem, William H.; Eugster, Hans P.

    1989-11-01

    Samples of Recent sediments, representing up to 1000 years of accumulation, were collected from three closed basin lakes (Mono Lake, CA, Walker Lake, NV, and Great Salt Lake, UT) to assess the effects of brine composition on the accumulation of total organic carbon, the concentration of dissolved organic carbon, humic acid structure and diagenesis, and trace metal complexation. The Great Salt Lake water column is a stratified Na-Mg-Cl-SO 4 brine with low alkalinity. Algal debris is entrained in the high density (1.132-1.190 g/cc) bottom brines, and in this region maximum organic matter decomposition occurs by anaerobic processes, with sulfate ion as the terminal electron acceptor. Organic matter, below 5 cm of the sediment-water interface, degrades at a very slow rate in spite of very high pore-fluid sulfate levels. The organic carbon concentration stabilizes at 1.1 wt%. Mono Lake is an alkaline (Na-CO 3-Cl-SO 4) system. The water column is stratified, but the bottom brines are of lower density relative to the Great Salt Lake, and sedimentation of algal debris is rapid. Depletion of pore-fluid sulfate, near l m of core, results in a much higher accumulation of organic carbon, approximately 6 wt%. Walker Lake is also an alkaline system. The water column is not stratified, and decomposition of organic matter occurs by aerobic processes at the sediment-water interface and by anaerobic processes below. Total organic carbon and dissolved organic carbon concentrations in Walker Lake sediments vary with location and depth due to changes in input and pore-fluid sulfate concentrations. Nuclear magnetic resonance studies ( 13C) of humic substances and dissolved organic carbon provide information on the source of the Recent sedimentary organic carbon (aquatic vs. terrestrial), its relative state of decomposition, and its chemical structure. The spectra suggest an algal origin with little terrestrial signature at all three lakes. This is indicated by the ratio of aliphatic to aromatic carbon and the absence of chemical structures indicative of the lignin of vascular plants. The dissolved organic carbon of the Mono Lake pore fluids is structurally related to humic acid and is also related to carbohydrate metabolism. The alkaline pore fluids, due to high pH, solubilize high molecular weight organic matter from the sediments. This hydrophilic material is a metal complexing agent. Despite very high algal productivities, organic carbon accumulation can be low in stratified lakes if the anoxic bottom waters are hypersaline with high concentrations of sulfate ion. Labile organic matter is recycled to the water column and the sedimentary organic matter is relatively nonsusceptible to bacterial metabolism. As a result, pore-fluid dissolved organic carbon and metal-organic complexation are low.

  7. Modern strain localization in the central Walker Lane, western United States: Implications for the evolution of intraplate deformation in transtensional settings

    NASA Astrophysics Data System (ADS)

    Surpless, Benjamin

    2008-10-01

    Approximately 25% of the differential motion between the Pacific and North American plates occurs in the Walker Lane, a zone of dextral motion within the western margin of the Basin and Range province. At the latitude of Lake Tahoe, the central Walker Lane has been considered a zone of transtension, with strain accommodated by dip-slip, strike-slip, and oblique-slip faults. Geologic data indicate that extension and strike-slip motion are partitioned across the central Walker Lane, with dip-slip motion resulting in E-W to ESE-WNW extension along the present-day western margin of the central Walker Lane since approximately 15 Ma, and dextral strike-slip motion across a zone further east since as early as 24 Ma. GPS velocity data suggest that present-day strain continues to be strongly partitioned and localized across the same regions established by geologic data. Velocity data across the central Walker Lane suggest a minimum of 2 mm/yr extensional strain focused along the western margin of the belt, with very little extension across either the central or eastern portions of the Walker Lane. These data indicate very little dextral motion across the central and western portions of the domain, with dextral motion of 3-5 mm/yr presently focused along a discrete zone of the eastern part of the central Walker Lane, coincident with existing, mapped strike-slip faults. Historic seismic data reveal little seismic activity in areas of Late Holocene dip-slip motion in the west or dextral motion in the east, suggesting a period of quiescence in the earthquake cycle and the likelihood of future activity in both areas. Based on this and previous studies, it is likely that a combination of pre-Cenozoic crustal structure, a relatively weak lithosphere beneath the Walker Lane, and long-term low stress ratios in the crust have permitted the long-term partitioning of dextral and extensional strain exhibited across the central Walker Lane. The present-day location of dextral strain in the central Walker Lane is subparallel with dextral deformation documented in the northern Walker Lane, suggesting that as strain continues to accumulate, these two discrete zones could become a continuous strike-slip system which will play a more important role in the future accommodation of relative Pacific-North American plate motion.

  8. B-29 mothership with pilots - Payne, Butchart, Walker, Littleton, and Moise

    NASA Technical Reports Server (NTRS)

    1953-01-01

    This photo shows the B-29 in the background with Dick Payne, Stan Butchart, and Joe Walker standing in front of it, Charles Littleton and John Moise squatting. The Boeing B-29 was the first U.S. aircraft to be modified to serve as an airborne launch vehicle. Last operated by the NASA High-Speed Flight Station (now the Dryden Flight Research Center, Edwards, California), the B-29 aircraft was used to launch the X-1 series aircraft, including the X-1-1, the X-1-2 (later redesignated the X-1E), the X-1A, and the X-1B. The B-29, which was accepted by the Air Force on Aug. 2, 1945, was operated by the NACA, NASA, the U.S. Air Force, and the Bell Aircraft Company. The Air Force transferred the B-29 to Bell Aircraft Company where it was modified to act as a carrier, or 'mothership,' for the first X-1. After modification, the aircraft flew to Pinecastle Army Air Base, Florida, where it made aeronautical history on Jan. 25, 1946, with its air launch of the first X-1. It then performed 10 drops of the X-1 at Pinecastle before flying to Edwards Air Force Base, California, in September 1946 where it dropped the X-1 for its first powered flight on Dec. 9, 1946. On Oct. 14, 1947, the B-29 again participated in a major aeronautical advance when it air launched the X-1 aircraft, which proceeded to exceed the speed of sound (Mach 1) for the first time. Air Force Pilot Captain Charles 'Chuck' Yeager was at the controls of the X-1 that day. A mid-air explosion in the 'captive' X-1A almost ended the career of the B-29 on Aug. 8, 1955. But pilot Stanley P. Butchart dropped the X-1A to its destruction in the desert after X-1A pilot, Joseph A. Walker, had scrambled back into the B-29. The B-29's 14-year career ended on July 1, 1959, when it was flown from the NASA High-Speed Flight Station to Davis-Monthan Air Force Base, Arizona, for retirement. The aircraft was made obsolete as a mothership by the advent of the X-15 Program, which required a larger, faster launch vehicle, the B-52. In the meantime, from 1950 to 1956, the NACA had used a P2B-1S (a Navy version of the B-29) to launch the rocket-powered versions of the D-558-2 research aircraft.

  9. On the broad-band spectral-energy distribution of the early-type young star LHalpha 25 = Walker 90

    Microsoft Academic Search

    A. E. Rydgren; F. J. Vrba

    1987-01-01

    New infrared photometry in the wavelength range 1 to 20 microns is presented for the unusual early-type star LHalpha 25 = Walker 90 in the young cluster NGC 2264. Together with previously-published UBVRI photometry, these data show that the broad-band spectral-energy distribution of this star has a minimum near a wavelength of 1 micron and rises rapidly to a wavelength

  10. VarWalker: Personalized Mutation Network Analysis of Putative Cancer Genes from Next-Generation Sequencing Data

    PubMed Central

    Jia, Peilin; Zhao, Zhongming

    2014-01-01

    A major challenge in interpreting the large volume of mutation data identified by next-generation sequencing (NGS) is to distinguish driver mutations from neutral passenger mutations to facilitate the identification of targetable genes and new drugs. Current approaches are primarily based on mutation frequencies of single-genes, which lack the power to detect infrequently mutated driver genes and ignore functional interconnection and regulation among cancer genes. We propose a novel mutation network method, VarWalker, to prioritize driver genes in large scale cancer mutation data. VarWalker fits generalized additive models for each sample based on sample-specific mutation profiles and builds on the joint frequency of both mutation genes and their close interactors. These interactors are selected and optimized using the Random Walk with Restart algorithm in a protein-protein interaction network. We applied the method in >300 tumor genomes in two large-scale NGS benchmark datasets: 183 lung adenocarcinoma samples and 121 melanoma samples. In each cancer, we derived a consensus mutation subnetwork containing significantly enriched consensus cancer genes and cancer-related functional pathways. These cancer-specific mutation networks were then validated using independent datasets for each cancer. Importantly, VarWalker prioritizes well-known, infrequently mutated genes, which are shown to interact with highly recurrently mutated genes yet have been ignored by conventional single-gene-based approaches. Utilizing VarWalker, we demonstrated that network-assisted approaches can be effectively adapted to facilitate the detection of cancer driver genes in NGS data. PMID:24516372

  11. Superfund Record of Decision (EPA Region 4): Mathis Brothers Landfill (South Marble Top Road), Walker County, GA, March 1993

    SciTech Connect

    Not Available

    1993-03-01

    This decision document (Record of Decision) presents the selected remedial action for the Mathis Brothers - South Marble Top Road Landfill site, Walker County, Georgia. At this time the remedial action is proposed as both the first, and the final remedial action for the site. The function of this remedy is to treat contamination and reduce it to health based levels. Source material and contaminated soils are the principal threat at the site.

  12. Bicycle Helmet Wearing Is Not Associated with Close Motor Vehicle Passing: A Re-Analysis of Walker, 2007

    PubMed Central

    Olivier, Jake; Walter, Scott R.

    2013-01-01

    Objectives To re-analyse bicycle overtaking data collected by Walker (2007) with a view to assess factors associated with close passing (<1 m), to adjust for other observed factors in a multivariable analysis, and to assess the extent to which the sample size in the original analysis may have contributed to spurious results. Method A re-analysis of 2,355 motor vehicle passing events recorded by Walker that includes information on cyclist's distance to the kerb, vehicle size and colour, city of observation, time of day, whether the event occurred while in a bikelane and helmet wearing. Each variable was considered for a final, multivariable model using purposeful selection of variables. The analysis was repeated using multiple logistic regression with passing distance dichotomised by the one metre rule. Bootstrap p-values were computed using sample sizes computed from conventional values of power and effect size. Results The previously observed significant association between passing distance and helmet wearing was not found when dichotomised by the one metre rule. Other factors were found to be significantly associated with close passing including cyclists' distance to the kerb, vehicle size and city of observation (Salisbury or Bristol, UK). P-values from bootstrap samples indicate the significance of helmet wearing resulted from an overly large sample size. Conclusions After re-analysis of Walker's data, helmet wearing is not associated with close motor vehicle passing. The results, however, highlight other more important factors that may inform effective bicycle safety strategies. PMID:24086528

  13. Walker devices and microswitch technology to enhance assisted indoor ambulation by persons with multiple disabilities: three single-case studies.

    PubMed

    Lancioni, Giulio E; Singh, Nirbhay N; O'Reilly, Mark F; Sigafoos, Jeff; Oliva, Doretta; Campodonico, Francesca; Buono, Serafino

    2013-07-01

    These three single-case studies assessed the use of walker devices and microswitch technology for promoting ambulation behavior among persons with multiple disabilities. The walker devices were equipped with support and weight lifting features. The microswitch technology ensured that brief stimulation followed the participants' ambulation responses. The participants were two children (i.e., Study I and Study II) and one man (i.e., Study III) with poor ambulation performance. The ambulation efforts of the child in Study I involved regular steps, while those of the child in Study II involved pushing responses (i.e., he pushed himself forward with both feet while sitting on the walker's saddle). The man involved in Study III combined his poor ambulation performance with problem behavior, such as shouting or slapping his face. The results were positive for all three participants. The first two participants had a large increase in the number of steps/pushes performed during the ambulation events provided and in the percentages of those events that they completed independently. The third participant improved his ambulation performance as well as his general behavior (i.e., had a decline in problem behavior and an increase in indices of happiness). The wide-ranging implications of the results are discussed. PMID:23643772

  14. The complete mitochondrial genome of the flesh fly, Sarcophaga impatiens Walker (Diptera: Sarcophagidae).

    PubMed

    Nelson, Leigh A; Cameron, Stephen L; Yeates, David K

    2012-02-01

    Approximately 2500 fly species comprise the Sarcophagidae family worldwide. The complete mitochondrial genome of the carrion-breeding, forensically important Sarcophaga impatiens Walker (Diptera: Sarcophagidae) from Australia was sequenced. The 15,169 bp circular genome contains the 37 genes found in a typical Metazoan genome: 13 protein-coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes. It also contains one non-coding A þ T-rich region. The arrangement of the genes was the same as that found in the ancestral insect. All the protein initiation codons are ATN, except for cox1 that begins with TCG (encoding S). The 22 tRNA anticodons of S. impatiens are consistent with those observed in Drosophila yakuba, and all form the typical cloverleaf structure, except for tRNA-Ser((AGN)) that lacks the DHU arm. The mitochondrial genome of Sarcophaga presented will be valuable for resolving phylogenetic relationships within the family Sarcophagidae and the order Diptera, and could be used to identify favourable genetic markers for species identifications for forensic purposes. PMID:22292894

  15. Stress-energy tensor of the quantized massive fields in Friedman-Robertson-Walker spacetimes

    NASA Astrophysics Data System (ADS)

    Matyjasek, Jerzy; Sadurski, Pawe?

    2013-11-01

    The approximate stress-energy tensor of the quantized massive scalar, spinor, and vector fields in the spatially flat Friedman-Robertson-Walker universe is constructed. It is shown that for the scalar fields with arbitrary curvature coupling, ?, the stress-energy tensor calculated within the framework of the Schwinger-DeWitt approach is identical to the analogous tensor constructed in the adiabatic vacuum. Similarly, the Schwinger-DeWitt stress-energy tensor for the fields of spin 1/2 and 1 coincides with the analogous result calculated by the Zeldovich-Starobinsky method. The stress-energy tensors thus obtained are subsequently used in the backreaction problem. It is shown that for pure semiclassical Einstein field equations with the vanishing cosmological constant and the source term consisting exclusively of its quantum part, there are no self-consistent exponential solutions driven by the spinor and vector fields. A similar situation takes place for the scalar field if the coupling constant belongs to the interval ??0.1. For a positive cosmological constant, the expansion slows down for all considered types of massive fields except for minimally coupled scalar field. The perturbative approach to the problem is briefly discussed and possible generalizations of the stress-energy tensor are indicated.

  16. Synopsis of the 6th Walker's Cay Colloquium on Cancer Vaccines and Immunotherapy

    PubMed Central

    Kast, W Martin; Levitsky, Hyam; Marincola, Francesco M

    2004-01-01

    The 6th annual Cancer Vaccines and Immunotherapy Colloquium at Walker's Cay was held under the auspices of the Albert B. Sabin Vaccine Institute on March 10–13, 2004. The Colloquium consisted of a select group of 34 scientists representing academia, biotechnology and pharmaceutical industry. The main goal of this gathering was to promote in a peaceful and comfortable environment exchanges between basic and clinical science. The secondary benefit was to inspire novel bench to bedside ventures and at the same time provide feed back about promising and/or disappointing clinical results that could help re-frame some scientific question or guide the design of future trials. Several topics were covered that included tumor antigen discovery and validation, platforms for vaccine development, tolerance, immune suppression and tumor escape mechanisms, adoptive T cell therapy and dendritic cell-based therapies, clinical trials and assessment of response. Here we report salient points raised by speakers or by the audience during animated discussion that followed each individual presentation. PMID:15212694

  17. Interacting cosmic fluids in power-law Friedmann-Robertson-Walker cosmological models

    E-print Network

    Mauricio Cataldo; Patricio Mella; Paul Minning; Joel Saavedra

    2008-03-07

    We provide a detailed description for power--law scaling Friedmann-Robertson-Walker cosmological scenarios dominated by two interacting perfect fluid components during the expansion. As a consequence of the mutual interaction between the two fluids, neither component is conserved separately and the energy densities are proportional to $1/t^{2}$. It is shown that in flat FRW cosmological models there can exist interacting superpositions of two perfect fluids (each of them having a positive energy density) which accelerate the expansion of the universe. In this family there also exist flat power law cosmological scenarios where one of the fluids may have a ``cosmological constant" or "vacuum energy" equation of state ($p =-\\rho$) interacting with the other component; this scenario exactly mimics the behavior of the standard flat Friedmann solution for a single fluid with a barotropic equation of state. These possibilities of combining interacting perfect fluids do not exist for the non-interacting mixtures of two perfect cosmic fluids, where the general solution for the scale factor is not described by power--law expressions and has a more complicated behavior. In this study is considered also the associated single fluid model interpretation for the interaction between two fluids.

  18. The Non-Diagonal Models of the Robertson-Walker Universe in General Relativity

    NASA Astrophysics Data System (ADS)

    Beloushko, Konstantin; Karbanovski, Valeri; Belenkova, Anastasiya

    As is known, the Robertson-Walker metric describe a homogeneous and isotropic universe. For this metric recorded in diagonal form, the equations of general relativity (GR) give the energy-momentum tensor (EMT), which will also have a diagonal form. In [1] it was shown that nondegenerate coordinate transformations can lead metric to non-diagonal mean that allows to get non-diagonal components of the EMT. This allows: begin{enumerate} build a model of the Universe of "ordinary" matter without resorting to the "exotic"; enter into the model the observed cosmic microwave background, which correspond to non-diagonal components of the EMT (energy flux density and components of stress tensor); reconcile heterogeneous distribution of matter with overall homogeneity of space-time geometry. The task of constructing the model is reduced to the choice of the type of metric functions, which will ensure the implementation of the standard physical conditions and allowed to clarify the evolution of the universe. Reference begin{enumerate} V.V. Karbanovski et al. - JETP, 112 (2011), 60.

  19. Preserving information from the beginning to the end of time in a Robertson–Walker spacetime

    NASA Astrophysics Data System (ADS)

    Mancini, Stefano; Pierini, Roberto; Wilde, Mark M.

    2014-12-01

    Preserving information stored in a physical system subjected to noise can be modeled in a communication-theoretic paradigm, in which storage and retrieval correspond to an input encoding and output decoding, respectively. The encoding and decoding are then constructed in such a way as to protect against the action of a given noisy quantum channel. This paper considers the situation in which the noise is not due to technological imperfections, but rather to the physical laws governing the evolution of the Universe. In particular, we consider the dynamics of quantum systems under a 1 + 1 Robertson–Walker spacetime and find that the noise imparted to them is equivalent to the well known amplitude damping channel. Since one might be interested in preserving both classical and quantum information in such a scenario, we study trade-off coding strategies and determine a region of achievable rates for the preservation of both kinds of information. For applications beyond the physical setting studied here, we also determine a trade-off between achievable rates of classical and quantum information preservation when entanglement assistance is available.

  20. Mutations in PIEZO2 cause Gordon syndrome, Marden-Walker syndrome, and distal arthrogryposis type 5.

    PubMed

    McMillin, Margaret J; Beck, Anita E; Chong, Jessica X; Shively, Kathryn M; Buckingham, Kati J; Gildersleeve, Heidi I S; Aracena, Mariana I; Aylsworth, Arthur S; Bitoun, Pierre; Carey, John C; Clericuzio, Carol L; Crow, Yanick J; Curry, Cynthia J; Devriendt, Koenraad; Everman, David B; Fryer, Alan; Gibson, Kate; Giovannucci Uzielli, Maria Luisa; Graham, John M; Hall, Judith G; Hecht, Jacqueline T; Heidenreich, Randall A; Hurst, Jane A; Irani, Sarosh; Krapels, Ingrid P C; Leroy, Jules G; Mowat, David; Plant, Gordon T; Robertson, Stephen P; Schorry, Elizabeth K; Scott, Richard H; Seaver, Laurie H; Sherr, Elliott; Splitt, Miranda; Stewart, Helen; Stumpel, Constance; Temel, Sehime G; Weaver, David D; Whiteford, Margo; Williams, Marc S; Tabor, Holly K; Smith, Joshua D; Shendure, Jay; Nickerson, Deborah A; Bamshad, Michael J

    2014-05-01

    Gordon syndrome (GS), or distal arthrogryposis type 3, is a rare, autosomal-dominant disorder characterized by cleft palate and congenital contractures of the hands and feet. Exome sequencing of five GS-affected families identified mutations in piezo-type mechanosensitive ion channel component 2 (PIEZO2) in each family. Sanger sequencing revealed PIEZO2 mutations in five of seven additional families studied (for a total of 10/12 [83%] individuals), and nine families had an identical c.8057G>A (p.Arg2686His) mutation. The phenotype of GS overlaps with distal arthrogryposis type 5 (DA5) and Marden-Walker syndrome (MWS). Using molecular inversion probes for targeted sequencing to screen PIEZO2, we found mutations in 24/29 (82%) DA5-affected families and one of two MWS-affected families. The presence of cleft palate was significantly associated with c.8057G>A (Fisher's exact test, adjusted p value < 0.0001). Collectively, although GS, DA5, and MWS have traditionally been considered separate disorders, our findings indicate that they are etiologically related and perhaps represent variable expressivity of the same condition. PMID:24726473

  1. Mutations in PIEZO2 Cause Gordon Syndrome, Marden-Walker Syndrome, and Distal Arthrogryposis Type 5

    PubMed Central

    McMillin, Margaret J.; Beck, Anita E.; Chong, Jessica X.; Shively, Kathryn M.; Buckingham, Kati J.; Gildersleeve, Heidi I.S.; Aracena, Mariana I.; Aylsworth, Arthur S.; Bitoun, Pierre; Carey, John C.; Clericuzio, Carol L.; Crow, Yanick J.; Curry, Cynthia J.; Devriendt, Koenraad; Everman, David B.; Fryer, Alan; Gibson, Kate; Giovannucci Uzielli, Maria Luisa; Graham, John M.; Hall, Judith G.; Hecht, Jacqueline T.; Heidenreich, Randall A.; Hurst, Jane A.; Irani, Sarosh; Krapels, Ingrid P.C.; Leroy, Jules G.; Mowat, David; Plant, Gordon T.; Robertson, Stephen P.; Schorry, Elizabeth K.; Scott, Richard H.; Seaver, Laurie H.; Sherr, Elliott; Splitt, Miranda; Stewart, Helen; Stumpel, Constance; Temel, Sehime G.; Weaver, David D.; Whiteford, Margo; Williams, Marc S.; Tabor, Holly K.; Smith, Joshua D.; Shendure, Jay; Nickerson, Deborah A.; Bamshad, Michael J.

    2014-01-01

    Gordon syndrome (GS), or distal arthrogryposis type 3, is a rare, autosomal-dominant disorder characterized by cleft palate and congenital contractures of the hands and feet. Exome sequencing of five GS-affected families identified mutations in piezo-type mechanosensitive ion channel component 2 (PIEZO2) in each family. Sanger sequencing revealed PIEZO2 mutations in five of seven additional families studied (for a total of 10/12 [83%] individuals), and nine families had an identical c.8057G>A (p.Arg2686His) mutation. The phenotype of GS overlaps with distal arthrogryposis type 5 (DA5) and Marden-Walker syndrome (MWS). Using molecular inversion probes for targeted sequencing to screen PIEZO2, we found mutations in 24/29 (82%) DA5-affected families and one of two MWS-affected families. The presence of cleft palate was significantly associated with c.8057G>A (Fisher’s exact test, adjusted p value < 0.0001). Collectively, although GS, DA5, and MWS have traditionally been considered separate disorders, our findings indicate that they are etiologically related and perhaps represent variable expressivity of the same condition. PMID:24726473

  2. Innovative use of an automated horse walker when breaking in young horses.

    PubMed

    Murphy, Jack

    2008-01-01

    There is an inherent element of risk associated with "backing" and riding the previously unbroken horse. If training proceeds too quickly, conflict behaviors may result from the simultaneous application of too many cues. Automated horse walkers (AHW) facilitate the exercising of several horses concurrently at walk or trot for warm-up, cool-down, fitness programs, and rehabilitation purposes. The objective of this study was to investigate if backing the horse within the AHW was an appropriate training method. Ten horses (3-year-olds) took part in this study. They began training within the AHW with a simple bridle and protective boots. A handler subsequently long-reined the horses within the AHW when they wore rollers, side reins, and a saddle. When considered appropriate, the handler went from jumping beside the horse to lying over the saddle to sitting astride the horse within the AHW. The horses habituated to this innovative approach quickly without evidence of conflict behavior. The handler rode the horses from the AHW after approximately 4 riding episodes of this innovative training system. PMID:18569219

  3. Population decrease of Scirpophaga incertulas Walker (Lepidoptera Pyralidae) under climate warming

    PubMed Central

    Shi, Peijian; Zhong, Ling; Sandhu, Hardev S; Ge, Feng; Xu, Xiaoming; Chen, Wei

    2012-01-01

    Scirpophaga incertulas Walker is an important agricultural pest in Asia. Only few studies are available on its long-term population dynamics under climate warming. In this study, we used the linear and generalized additive models (GAMs) to analyze the historical dataset of >50 years on this pest at Xinfeng County of Jiangxi Province, China. The main objective of this study was to explore the effects of density (delayed) dependence and minimum annual temperature (MAT), which indirectly reflects climate warming, on the population dynamics of this pest. We found that both density dependence and MAT have significant influence on the annual population growth rate. The GAMs had relatively better applicability to the dataset than the linear models. Nonparametric model provided satisfactory goodness-of-fit (R2 > 0.5). At Xinfeng County, the MAT had a significant effect on the annual population growth rate of S. incertulas. The annual population growth rate of S. incertulas decreased with increase in MAT. Therefore, S. incertulas population becomes smaller and smaller in Southern China due to climate warming. The current study has two contributions: (1) providing a suitable method for predicting the annual population growth rate of S. incertulas, and (2) demonstrating that climate warming could decrease the S. incertulas population. PMID:22408726

  4. Airborne SAR determination of relative ages of Walker Valley moraines, eastern Sierra Nevada

    NASA Technical Reports Server (NTRS)

    Fox, A.; Isacks, B.; Bloom, A.; Fielding, E.; Mcmurry, D.

    1991-01-01

    A regional study of the distribution and elevations of Pleistocene moraines in the Andes requires a method of determining relative age from space. One of our primary objectives is to establish the relative chronology of major climatic events responsible for glaciation in the Andes and other regions that are difficult to access on the ground and where suitable material for absolute age determination is lacking. The sensitivity of radar to surface roughness makes it possible to develop a remotely-based relative dating technique for landforms for which surface age and roughness can be correlated. We are developing such a technique with Airborne Synthetic Aperture Radar (AIRSAR) imagery of the eastern Sierra Nevada where independent evidence is available for the ages and physical characteristics of moraines. The Sierra Nevada moraines are similar in form and environmental setting to Andean moraines that we have targeted for study during the pending Shuttle Imaging Radar-C (SIR-C) mission. SAR imagery is used to differentiate the ages of five moraine sequences of Walker Valley in the eastern Sierra Nevada. Other aspects of this investigation are briefly discussed.

  5. South China Sea hydrological changes and Pacific Walker Circulation variations over the last millennium

    PubMed Central

    Yan, Hong; Sun, Liguang; Oppo, Delia W.; Wang, Yuhong; Liu, Zhonghui; Xie, Zhouqing; Liu, Xiaodong; Cheng, Wenhan

    2011-01-01

    The relative importance of north–south migrations of the intertropical convergence zone (ITCZ) versus El Niño-Southern Oscillation and its associated Pacific Walker Circulation (PWC) variability for past hydrological change in the western tropical Pacific is unclear. Here we show that north–south ITCZ migration was not the only mechanism of tropical Pacific hydrologic variability during the last millennium, and that PWC variability profoundly influenced tropical Pacific hydrology. We present hydrological reconstructions from Cattle Pond, Dongdao Island of the South China Sea, where multi-decadal rainfall and downcore grain size variations are correlated to the Southern Oscillation Index during the instrumental era. Our downcore grain size reconstructions indicate that this site received less precipitation during relatively warm periods, AD 1000–1400 and AD 1850–2000, compared with the cool period (AD 1400–1850). Including our new reconstructions in a synthesis of tropical Pacific records results in a spatial pattern of hydrologic variability that implicates the PWC. PMID:21522137

  6. Effect of methotrexate on perfusion and nitrogen-13 glutamate uptake in the Walker-256 carcinosarcoma

    SciTech Connect

    Knapp, W.H.; Panzer, M.; Helus, F.; Layer, K.; Sinn, H.J.; Ostertag, H.

    1988-02-01

    The tissue uptake of (/sup 13/N)glutamate (glu) was related to that of (/sup 11/C)butanol (but), a highly diffusible perfusion tracer. In 25 rats bearing Walker-256 carcinomas tumor-to-muscle glu uptake averaged 6.34 +/- 2.84 (s.d.) prior to interventions and the respective uptake of but was 6.79 +/- 3.08 (y = 0.03 + 0.94x). One hour after selective intraarterial administration of methotrexate (mtx), glu uptake fell by 47%, whereas blood flow remained within the pretreatment range (N = 9). Four hours after mtx, perfusion was reduced by approximately 40%, and 2 days later both perfusion and glu uptake reached extremely low levels. No significant difference in the effect of 10 and 50 mg/kg mtx was observed. Regional tissue mtx uptake estimations using /sup 77/Br-labeled bromomethotrexate did not reveal any significant uptake in muscle. The relationship between tumor-to-muscle uptake of glu and but (/sup 13/N//sup 11/C-index) was 0.94 +/- 0.015 (s.e.m., N = 25) before intervention. After methotrexate (1 hr, 4 hr, and 2 days) this index was 0.58 +/- 0.06 (N = 9), and 0.85 +/- 0.04 (N = 11) and 1.03 +/- 0.05 (N = 5), respectively. These values demonstrate an early mtx-induced uncoupling of glu uptake with respect to perfusion.

  7. Minimum of PDOP and its applications in inter-satellite links (ISL) establishment of Walker-? constellation

    NASA Astrophysics Data System (ADS)

    Han, Songhui; Gui, Qingming; Li, Guozhong; Du, Yuanlu

    2014-08-01

    Within the next decade, there will be a number of GNSS (Global Navigation Satellite System) available, i.e. modernized GPS, Galileo, restored GLONASS, BeiDou and many other regional GNSS augmentation systems. Thus, measurement redundancies and geometry of the satellites can be improved. GDOP (Geometric Dilution of Precision) and PDOP (Position Dilution of Precision) are associated with the constellation geometry of satellites, and they are the geometrically determined factors that describe the effect of geometry on the relationship between measurement error and position error. GDOP and PDOP are often used as standards for selecting good satellites to meet the desired positioning precision. In this paper, the related conclusions of minimum of GDOP which was discussed are given, and it is used to study the minimum of PDOP for two cases that the receiver is on the earth’s surface and the receiver is on satellite. The corresponding theorem and constructive solutions of minimum of PDOP are given. Then, the rationality of the ISL (inter-satellite link) establishment criteria in Walker-? constellation is discussed by using the theory of minimum of PDOP. Finally, the minimum of PDOP is calculated when the number of satellites is 4-10, and these results are verified by using Monte Carlo method.

  8. Field studies of streamflow generation using natural and injected tracers on Bickford and Walker Branch Watersheds

    SciTech Connect

    Genereux, D.; Hemond, H. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Civil Engineering; Mulholland, P. [Oak Ridge National Lab., TN (United States)

    1992-05-01

    Field studies of streamflow generation were undertaken on two forested watersheds, the West Road subcatchment of Bickford Watershed in central Massachusetts and the West Fork of Walker Branch Watershed in eastern Tennessee. A major component of the research was development of a two-stage methodology for the use of naturally-occurring {sup 222}Rn as a tracer. The first of the two stages was solving a mass-balance equation for {sup 222}Rn around a stream reach of interest in order to calculate Rn{sub q}, the {sup 222}Rn content of the lateral inflow to the reach; a conservative tracer (chloride) and a volatile tracer (propane) were injected into the study stream to account for lateral inflow to, and volatilization from, the study reach. The second stage involved quantitative comparison of Rn{sub q} to the measured {sup 222}Rn concentrations of different subsurface waters in order to assess how important these waters were in contributing lateral inflow to the stream reach.

  9. Expressed sequence tags from the midgut of Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae).

    PubMed

    Simpson, R M; Newcomb, R D; Gatehouse, H S; Crowhurst, R N; Chagné, D; Gatehouse, L N; Markwick, N P; Beuning, L L; Murray, C; Marshall, S D; Yauk, Y-K; Nain, B; Wang, Y-Y; Gleave, A P; Christeller, J T

    2007-12-01

    The midgut is a key tissue in insect science. Physiological roles include digestion and peritrophic membrane function, as well as being an important target for insecticides. We used an expressed sequence tag (EST) approach to identify candidate genes and gene families involved in these processes in the light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae). Two cDNA libraries were constructed from dissected midgut of third to fifth instar larvae. Clustering analysis of 6416 expressed sequence tags produced 1178 tentative unique genes comprising 725 tentative contigs and 453 singletons. The sequences show similar codon usage to sequences from other lepidopterans, a Kozak consensus sequence similar to Drosophila and single nucleotide polymorphisms (SNPs) were detected at a frequency of 1.35/kb. The identity of the most common Interpro families correlates well with major known functions of the midgut. Phylogenetic analysis was conducted on representative sequences from selected multigene families. Gene families include a broad range of digestive proteases, lipases and carbohydrases that appear to have degradative capacity against the major food components found in leaves, the diet of these larvae; and carboxylesterases, glutathione-S-transferases and cytochrome P450 monooxygenases, potentially involved in xenobiotic degradation. Two of the larger multigene families, serine proteases and lipases, expressed a high proportion of genes that are likely to be catalytically inactive. PMID:18092997

  10. Periodicity of sex pheromone biosynthesis, release and degradation in the lightbrown apple moth, Epiphyas postvittana (Walker).

    PubMed

    Foster, S P

    2000-03-01

    Pheromone titer in moths is a product of three processes occurring in or at the surface of the pheromone gland: biosynthesis, release, and intraglandular degradation, of pheromone. Changes in titers of sex pheromone, the fatty acyl pheromone analog (FAPA), and tetradecanoate, a pheromone biosynthetic intermediate, were studied in detail in the lightbrown apple moth, Epiphyas postvittana (Walker). Although changes in the pheromone titers in a day were relatively small, with the peak titer being 2-3 times greater than that at the trough, pheromone titer did show a distinct diel periodicity. Titer of the FAPA showed a similar, but less variable, diel pattern, but tetradecanoate titer showed little or no diel pattern. The pattern of pheromone titer suggested that females biosynthesize pheromone at two different rates during the photoperiod: a high rate during the latter half of the photophase and most of the scotophase, which is associated with a high pheromone titer, and a low rate throughout the first half of the photophase, which is associated with a low titer. Consistent with data on commencement of copulation, pheromone was released from the second hour of the scotophase through to the eighth hour. Pheromone release rate during this period appeared to be similar to the rate of pheromone biosynthesis. In contrast to the other two processes, pheromone degradation did not appear to have a diel pattern. Females decapitated at different times of the photoperiod showed a similar decline in pheromone titer, consistent with the reaction kinetics being first order in pheromone titer. PMID:10685100

  11. Mercury in the Walker River Basin, Nevada and California--sources, distribution, and potential effects on the ecosystem

    USGS Publications Warehouse

    Seiler, Ralph L.; Lico, Michael S.; Wiemeyer Evers, David C.

    2004-01-01

    Mercury is one of the most serious contaminants of water, sediment, and biota in Nevada because of its use during 19th century mining activities to recover gold and silver from ores. In 1998, mercury problems were discovered in the Walker River Basin of California and Nevada when blood drawn from three common loons from Walker Lake was analyzed and found to have severely elevated mercury levels. From 1999 to 2001, the U.S. Geological Survey and the U.S. Fish and Wildlife Service collected water, sediment, and biological samples to determine mercury sources, distribution, and potential effects on the Walker River Basin ecosystem. Total-mercury concentrations ranged from 0.62 to 57.11 ng/L in streams from the Walker River system and ranged from 1.02 to 26.8 ng/L in lakes and reservoirs. Total-mercury concentrations in streambed sediment ranged from 1 to 13,600 ng/g, and methylmercury concentrations ranged from 0.07 to 32.1 ng/g. The sediment-effects threshold for mercury for fresh-water invertebrates is 200 ng/g, which was exceeded at nine stream sites in the Walker River Basin. The highest mercury concentrations were in streams with historic mines and milling operations in the watershed. The highest mercury concentration in sediment, 13,600 ng/g, was found in Bodie Creek near Bodie, Calif., a site of extensive gold mining and milling activities during the 19th century. Sediment cores taken from Walker Lake show total-mercury concentrations exceeding 1,000 ng/g at depths greater than 15 cm below lake bottom. The presence of 137Cs above 8 cm in one core indicates that the upper 8 cm was deposited sometime after 1963. The mercury peak at 46 cm in that core, 2,660 ng/g, likely represents the peak of mining and gold extraction in the Bodie and Aurora mining districts between 1870 and 1880. Mercury concentrations in aquatic invertebrates at all sites downstream from mining activities in the Rough Creek watershed, which drains the Bodie and Aurora mining districts, were elevated (range 0.263 to 0.863 ?g/g, dry weight). Mercury concentrations in the Walker Lake tui chub, the most abundant and likely prey for common loons, ranged from approximately 0.09 ?g/g to approximately 0.9 ?g/g (wet weight). Larger tui chub in the lake, which are most likely older, had the highest mercury concentrations. Blood samples from 94 common loons collected at Walker Lake between 1998 and 2001 contained a mean mercury concentration of 2.96 ?g/g (standard deviation 1.72 ?g/g). These levels were substantially higher than those found in more than 1,600 common loons tested across North America. Among the 1,600 common loons, the greatest blood mercury concentration, 9.46 ?g/g, was from a loon at Walker Lake. According to risk assessments for northeastern North America, blood mercury concentrations exceeding 3.0 ?g/g cause behavioral, reproductive, and physiological effects. At least 52 percent of the loons at Walker Lake are at risk for adverse effects from mercury on the basis of their blood-mercury concentrations. The larger loons staging in the spring are the most at risk group. The elevated mercury levels found in tui chub and common loons indicate that there is a potential threat to the well being and reproduction of fish and wildlife that use Walker Lake. Wildlife that use Weber Reservoir may also be at risk because it is the first reservoir downstream from mining activities in the Bodie and Aurora areas and mercury concentrations in sediment were elevated. Additional data on mercury concentrations in top level predators, such as piscivorous fish and birds, are needed to assess public health and other environmental risks.

  12. The Inhomogeneous Tropospheric Warming as the Driver of Tropical Sea Level Pressure and Walker Circulation Changes

    NASA Astrophysics Data System (ADS)

    Bayr, Tobias; Dommenget, Dietmar

    2013-04-01

    In this presentation we follow the idea to split up the global warming signal in a spatial homogeneous warming and in a spatial inhomogeneous warming. In Bayr and Dommenget (2012) the changes of the tropical sea level pressure (SLP) due to inhomogeneous tropospheric warming in climate change, which is mostly the land-sea warming contrast, was investigated in a multi model ensemble. The amplitude of the inhomogeneous tropospheric warming is roughly 10 times smaller than the total warming of the tropical troposphere, but it can explain on average two third of the tropical SLP changes in different climate models. The explained SLP changes are of hydrostatical nature. As the zonal temperature differences are the main driver of the zonal circulation cells like the Walker Circulation, the inhomogeneous tropospheric warming also changes the zonal circulations. This response is simulated with Atmospheric General Circulation Model and compared with the effect of the homogenous warming on the zonal circulations. The results show that the effect of the inhomogeneous warming can be nearly contrary to the effect of the homogeneous warming, so strengthening of the zonal tropical circulations in the inhomogeneous warming case and a weakening as proposed by Vecchi and Soden (2007) in the homogeneous warming case. As the ratio between the homogeneous and inhomogeneous warming is model dependent, this can partly explain the spread in the response of the zonal circulations of the individual climate models. References Bayr, T., and D. Dommenget, 2012: The Tropospheric Land-Sea Warming Contrast as the Driver of Tropical Sea Level Pressure Changes. Journal of Climate, doi:10.1175/JCLI-D-11-00731.1. Vecchi, G. A., and B. J. Soden, 2007: Global Warming and the Weakening of the Tropical Circulation. Journal of Climate, 20, 4316-4340, doi:10.1175/JCLI4258.1.

  13. On a c(t)-Modified Friedman-Lemaitre-Robertson-Walker Universe

    E-print Network

    Robert C. Fletcher

    2013-07-22

    This paper presents a compelling argument for the physical light speed in the homogeneous and isotropic Friedman-Lemaitre-Robertson-Walker (FLRW) universe to vary with the cosmic time coordinate t of FLRW. It will be variable when the radial co-moving differential coordinate of FLRW is interpreted as physical and therefor transformable by a Lorentz transform locally to differentials of stationary physical coordinates. Because the FLRW differential radial distance has a time varying coefficient a(t), in the limit of a zero radial distance the light speed c(t) becomes time varying, proportional to the square root of the derivative of a(t) Since we assume homogeneity of space, this derived c(t) is the physical light speed for all events in the FLRW universe. This impacts the interpretation of astronomical observations of distant phenomena that are sensitive to light speed. A transform from FLRW is shown to have a physical radius out to all radial events in the visible universe. This shows a finite horizon beyond which there are no galaxies and no space. The general relativity (GR) field equation to determine a(t) and c(t) is maintained by using a variable gravitational constant and rest mass that keeps constant the gravitational and particle rest energies. This keeps constant the proportionality constant between the GR tensors of the field equation and conserves the stress-energy tensor of the ideal fluid used in the FLRW GR field equation. In the same way all of special and general relativity can be extended to include a variable light speed.

  14. Mass balance of trace elements in Walker branch watershed: relation to coal-fired steam plants.

    PubMed Central

    Lindberg, S E; Andren, A W; Raridon, R J; Fulkerson, W

    1975-01-01

    A mass balance study of trace element flows at the TVA Allen Steam Plant at Memphis showed that most of the released Hg, some Se, and probably most Cl and Br are discharged to the atmosphere as gases. The elements As, Cd, Cu, Ga, Mo, Pb, Sb, Se, and Zn were concentrated in fly ash compared to slag and were more concentrated in the ash discharged through the stack than in that collected by the precipitator, while Al, Ba, Ca, Ce, Co, Eu, Fe, Hf, K, La, Mg, Mn, Rb, Sm, Sr, Ta, Th, and Ti showed little preferential partitioning between the slag and the collected or discharged fly ash. The elements Cr, Cs, Na, Ni, U, and V exhibited behavior intermediate between the latter two groups. This information about stack emissions of trace elements from the Allen Plant was used to estimate the likely range of air concentrations and input (dry and wet deposition) to the Walker Branch Watershed. The watershed, which is on the ERDA reservation at Oak Ridge, is within 20 km of three coal-fired steam plants, two in the TVA system and one belonging to ERDA. The estimated input values are compared to measurements of Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn in wet precipitation falling on the watershed during 1973 and 1974. Dry deposition of these elements could not be measured directly but estimates indicated that this could be of the same order of magnitude as the rainwater input. A six-month mass balance indicated that the watershed efficiently retains Pb (97-98% of the atmospheric input,) Cu (82-84%), while Cr (69%), Mn (57%), Zn (73%), and Hg (69%) are less well retained. Images FIGURE 3. PMID:1227866

  15. Vacuum fluctuations and topological Casimir effect in Friedmann-Robertson-Walker cosmologies with compact dimensions

    NASA Astrophysics Data System (ADS)

    Saharian, A. A.; Mkhitaryan, A. L.

    2010-03-01

    We investigate the Wightman function, the vacuum expectation values of the field squared and the energy-momentum tensor for a massless scalar field with general curvature coupling parameter in spatially flat Friedmann-Robertson-Walker universes with an arbitrary number of toroidally compactified dimensions. The topological parts in the expectation values are explicitly extracted and in this way the renormalization is reduced to that for the model with trivial topology. In the limit when the comoving lengths of the compact dimensions are very short compared to the Hubble length, the topological parts coincide with those for a conformal coupling and they are related to the corresponding quantities in the flat spacetime by standard conformal transformation. This limit corresponds to the adiabatic approximation. In the opposite limit of large comoving lengths of the compact dimensions, in dependence of the curvature coupling parameter, two regimes are realized with monotonic or oscillatory behavior of the vacuum expectation values. In the monotonic regime and for non-conformally and non-minimally coupled fields the vacuum stresses are isotropic and the equation of state for the topological parts in the energy density and pressures is of barotropic type. For conformal and minimal couplings the leading terms in the corresponding asymptotic expansions vanish and the vacuum stresses, in general, are anisotropic, though the equation of state remains of barotropic type. In the oscillatory regime, the amplitude of the oscillations for the topological part in the expectation value of the field squared can be either decreasing or increasing with time, whereas for the energy-momentum tensor the oscillations are damping. The limits of validity of the adiabatic approximation are discussed.

  16. Electromagnetic two-point functions and the Casimir effect in Friedmann-Robertson-Walker cosmologies

    NASA Astrophysics Data System (ADS)

    Bellucci, S.; Saharian, A. A.

    2013-09-01

    We evaluate the two-point functions of the electromagnetic field in (D+1)-dimensional spatially flat Friedmann-Robertson-Walker universes with a power-law scale factor, assuming that the field is prepared in the Bunch-Davies vacuum state. The range of powers is specified in which the two-point functions are infrared convergent and the Bunch-Davies vacuum for the electromagnetic field is a physically realizable state. The two-point functions are applied for the investigation of the vacuum expectation values of the field squared and the energy-momentum tensor, induced by a single and two parallel conducting plates. Unlike to the case of conducting plates in the Minkowski bulk, in the problem under consideration, the stresses along the directions parallel to the plates are not equal to the energy density. We show that, in addition to the diagonal components, the vacuum energy-momentum tensor has a nonzero off-diagonal component which describes energy flux along the direction normal to the plates. For a single plate, this flux is directed from the plate. The Casimir forces are investigated in the geometry of two plates. At separations between the plates smaller than the curvature radius of the background spacetime, to the leading order, we recover the corresponding result in the Minkowski spacetime, and in this case the forces are attractive. At larger separations, the influence of the curvature on the Casimir forces is essential with different asymptotic behavior for decelerated and accelerated expansions. In particular, for the latter case, there is a range of powers of the expansion law in which the forces become repulsive at large separations between the plates.

  17. A taxonomic revision of the genus Edosa Walker, 1886 from China (Lepidoptera, Tineidae, Perissomasticinae).

    PubMed

    Yang, Linlin; Wang, Shuxia; Li, Houhun

    2014-01-01

    The genus Edosa Walker, 1886 is revised in China. Of the 31 recognized species, 23 are described as new: Edosa aurea sp. nov., E. baculiformis sp. nov., E. bicolor sp. nov., E. bifurcata sp. nov., E. carinata sp. nov., E. conchata sp. nov., E. cornuta sp. nov., E. curvidorsalis sp. nov., E. dentata sp. nov., E. digitata sp. nov., E. duoprojecta sp. nov., E. elongata sp. nov., E. eminens sp. nov., E. hamata sp. nov., E. longicornis sp. nov., E. minuta sp. nov., E. robinsoni sp. nov., E. robustispina sp. nov., E. semicircularis sp. nov., E. torta sp. nov., E. truncatula sp. nov., E. uncusella sp. nov., and E. varians sp. nov.; Edosa gaedikei nom. nov. is proposed as a replacement name for Edosa spinosa Gaedike, 2012, a junior homonym of Edosa spinosa Gaedike, 1984; four species are newly recorded for China: E. hendrixella Robinson, 2008, E. crayella Robinson, 2008, E. orphnodes (Meyrick, 1911) and E. smithaella Robinson, 2008; the female of E. hendrixella is described for the first time. Phylogenetic relationships of the Chinese species, except E. malthacopis (Meyrick, 1936), are postulated based on 42 morphological characters. The phylogenetic analysis of the morphology matrix yielded one most parsimonious tree (length 121 steps, CI = 0.56, RI = 0.81), based on which seven species-groups are proposed: the hemichrysella-group, the subochraceella-group, the pyrochra-group, the duoprojecta-group, the eminens-group, the crayella-group and the uncusella-group. The whole body structures of the genus are presented and photographs of adults and genitalia are provided, along with a key to all the known Chinese species and maps to show the distribution of Edosa in China. A world checklist of Edosa is given as an appendix, in which 41 new combinations are included. PMID:24871620

  18. Cenozoic strike-slip faults in the northern Wassuk Range, Walker Lane

    SciTech Connect

    Dilles, J.H. (Oregon State Univ., Corvallis, OR (United States). Geosciences Dept.)

    1993-04-01

    The N. Wassuk Ra. yields estimates of right-lateral Cenozoic strain in a portion of the northwest-trending Walker Lane, which has a total estimated right-lateral strain of 48--60 km (Ekren et al., 1984). The net right-lateral strain is < 10 km within an east-west 50 km-long segment extending from the N. Wassuk Ra. west to the Pine Nut Mts on the basis of continuous Jurassic plutonic units: Yerington batholith and quartz monzodiorite porphyry dikes. One of two dikes in the N. Wassuk Ra. may correlate easterly to Gillis Ra., suggesting [approximately]10 or 25 km right-lateral offset (Diles and R. Hardyman, unpub). In the N. Wassuk Ra. there are several ages of northwesterly striking faults. The oldest are [approximately]N45[degree]W striking, steeply dipping faults including the White Mt. and Wassuk Spur faults that step left to the northwest. Associated moderately dipping faults have tilted Oligocene tuffs to the W or SW to the SW of the fault zone, and both E and W on the NW; based on offset of the Jurassic porphyry dike and slickensides, these faults were dominantly oblique-slip normal faults with WNW-ESE slip. No lateral offsets can be directly measured across the steeply dipping faults; however, they juxtapose different Mesozoic metamorphic rocks and different thicknesses of Oligocene ignimbrites, suggesting significant lateral offset. Bingler's (1978) proposal that the White Mt. fault had left-laterally offset the White Mt. granite (WMG) from granite of Black Mountain (BMG) is unreasonable because the BMG intrudes the Wassuk Range diorite and contain biotite aplites, whereas the WMG intrudes metavolcanic rocks and contains tourmaline-muscovite aplites.

  19. Electrophoretic and centrifugation behaviour of mitochondrial ribonucleic acid from Walker 256 carcinosarcoma.

    PubMed Central

    González-Cadavid, N F; Pérez, J L

    1975-01-01

    To investigate the possibility that mitochondrial transcription could be altered in tumours we started by characterizing the RNA obtained from mitochondria, isolated from Walker carcinosarcoma and purified by a procedure devised to compensate for the lower size and density of these organelles in 10-day tumours. The RNA was extracted by the 'hot phenol' technique and analysed by electrophoresis in 2.7 and 2.5% polyacrylamide gels at different running times, identifying the usual cytoplasmic contaminants 28 and 18S peaks plus the other five major peaks at 40, 20.5, 16.3, 15.4, and 4Se. The 28 and 18Se peaks were not eliminated by digitonin treatment of the mitochondria, indicating that they arise from cytoplasmic ribosomes tightly associated with the mitochondria. From its sensitivity to DNAase (deoxyribonuclease), resistance to RNAase (ribonuclease) and coincidence with external marker DNA, the 40Se peak was identified as containing mainly DNA. Sucrosegradient centrifugation for different periods showed a major component at 16.2S, the 28 and 18S cytoplasmic RNA species, peaks at 13.8, 6.4 and 4S and a small 19.5S peak. By polyacrylamide-gel electrophoresis of the purified RNA classes separated by one or two cycles of centrifugation, the following correlation were established: 20.5Se19.5S; 16.3Se16.2S; 15.4Se13.8S. The 6.4S RNA ran as a mixture of 4 and 4.7Se species. When the 20.5Se and 15.4Se RNA species were centrifuged, they behaved as 16.2S and 13.8S respectively, thus suggesting that the 16.2S (16.3Se) arises by cleavage from the 19.5S(20.5Se), the 13.8S (15.4Se) being the other RNA from mitochondrial ribosomes. PMID:1156377

  20. Evidence for Interannual to Decadal Variations in Hadley and Walker Circulations and Links to Water and Energy Fluxes

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin; Bosilovich, Michael; Miller, Timothy

    2007-01-01

    Mass and energy transports associated with the Hadley and Walker circulations are important components of the earth s climate system and are strongly linked to hydrologic processes. Interannual to decadal variation in these flows likely signify a combination of natural climate noise as well as a response to anthropgenic forcing. There remains considerable uncertainty in quantifying variations in these flows. Evidence in the surface pressure record supports a weakening of the Walker circulation over the Pacific in recent decades. Conversely the NCEP / NCAR and ERA 40 reanalyses indicate that the Hadley circulation has increased in strength over the last two decades, though these analyses depict significantly different mass circulation changes. Interestingly, the NCEP - II / DOE reanalysis contains essentially no Hadley circulation changes. Most climate model integrations anticipate a weakening of both tropical circulations associated with stronger static stability. Clearly there is much uncertainty not only with the mass transports, but also how they are linked to water and energy balance of the planet through variations in turbulent heat and radiative fluxes and horizontal exports / imports of energy. Here we examine heat and water budget variations from a number of reanalysis products and focus on the linear and nonlinear response of ENSO warm and cold events as opportunities to study budget variations over the past 15-20 years. Our analysis addresses such questions as To what extent do Hadley and Walker Cell variations compensate each other on mass and energy transport? Do static stability adjustments appear to constrain fractional precipitation response vs. fractional water vapor response? We appeal to constraints offered by GPCP precipitation, SSWI ocean evaporation estimates, and ISCCP-FD radiative fluxes, and other satellite data sets to interpret and confirm reanalysis-based diagnostics. Using our findings we also attempt to place in context the recent findings that tropical ocean evaporation increased by order 5% or more during the 1990s, reconciling this with GPCP precipitation variations.

  1. Comment on 'Quantization of Friedmann-Robertson-Walker spacetimes in the presence of a negative cosmological constant and radiation'

    SciTech Connect

    Amore, Paolo; Aranda, Alfredo; Cervantes, Mayra; Diaz-Cruz, J. L.; Fernandez, Francisco M. [Facultad de Ciencias, Universidad de Colima, Bernal Diaz del Castillo 340, Colima, Colima (Mexico) and Facultad de Ciencias, Universidad de Colima, Bernal Diaz del Castillo 340, Colima, Colima, Mexico Facultad de Ciencias Fisico-Matematicas, BUAP Apdo. Postal 1364, C.P.72000 Puebla, Pue (Mexico); INIFTA (Conicet, UNLP), Division Quimica Teorica, Diag. 113 y 64 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)

    2007-03-15

    The quantization of the Friedmann-Robertson-Walker spacetime in the presence of a negative cosmological constant was used in a recent paper to conclude that there are solutions that avoid singularities (big bang-big crunch) at the quantum level. We show that a proper study of their model does not indicate that it prevents the occurrence of singularities at the quantum level, in fact the quantum probability of such event is larger than the classical one. Our numerical simulations based on the powerful variational sinc collocation method (VSCM) also show that the precision of the results of that paper is much lower than the 20 significant digits reported by the authors.

  2. Chronic supplementation with shark liver oil for reducing tumor growth and cachexia in walker 256 tumor-bearing rats.

    PubMed

    Iagher, Fabíola; de Brito Belo, Sérgio Ricardo; Naliwaiko, Katya; Franzói, Andressa Machado; de Brito, Gleisson Alisson Pereira; Yamazaki, Ricardo Key; Muritiba, Ana Lúcia; Muehlmann, Luis Alexandre; Steffani, Jovani Antonio; Fernandes, Luiz Cláudio

    2011-11-01

    We investigated the effect of chronic supplementation with shark liver oil (SLO), an antitumor supplement source of n-3 fatty acids and 1-O-alkylglycerols, alone and combined with coconut fat (CF), a source of saturated fatty acids, on Walker 256 tumor growth and cachexia. Male rats were supplemented daily and orally with SLO and/or CF (1 g per kg body weight) for 7 wk. After 7 wk, 50% of animals were subcutaneously inoculated with 3 × 10(7) Walker 256 tumor cells. After 14 days, the rats were killed, the tumors were removed for lipid peroxidation measurement, and blood was collected for glycemia, triacylglycerolemia, and lacticidemia evaluation. Liver samples were obtained for glycogen measurement. Unlike CF, supplementation with SLO promoted gain in body weight, reduction of tumor weight, and maintained glycemia, triacylglycerolemia, lacticidemia, and liver glycogen content to values similar to non-tumor-bearing rats. Combined supplementation of SLO with CF also showed a reversion of cachexia with gain in body mass, reduction of lacticidemia, maintaining the liver glycogen store, and reduction in tumor weight. SLO, alone or combined with CF, promoted increase of tumor lipid peroxidation. In conclusion, SLO supplemented chronically, alone or associated with CF, was able to reduce tumor growth and cachexia. PMID:21981555

  3. Buses, cars, bicycles and walkers: the influence of the type of human transport on the flight responses of waterbirds.

    PubMed

    McLeod, Emily M; Guay, Patrick-Jean; Taysom, Alice J; Robinson, Randall W; Weston, Michael A

    2013-01-01

    One way to manage disturbance to waterbirds in natural areas where humans require access is to promote the occurrence of stimuli for which birds tolerate closer approaches, and so cause fewer responses. We conducted 730 experimental approaches to 39 species of waterbird, using five stimulus types (single walker, three walkers, bicycle, car and bus) selected to mimic different human management options available for a controlled access, Ramsar-listed wetland. Across species, where differences existed (56% of 25 cases), motor vehicles always evoked shorter flight-initiation distances (FID) than humans on foot. The influence of stimulus type on FID varied across four species for which enough data were available for complete cross-stimulus analysis. All four varied FID in relation to stimuli, differing in 4 to 7 of 10 possible comparisons. Where differences occurred, the effect size was generally modest, suggesting that managing stimulus type (e.g. by requiring people to use vehicles) may have species-specific, modest benefits, at least for the waterbirds we studied. However, different stimulus types have different capacities to reduce the frequency of disturbance (i.e. by carrying more people) and vary in their capacity to travel around important habitat. PMID:24367498

  4. ?-Linolenic Fatty Acid Supplementation Decreases Tumor Growth and Cachexia Parameters in Walker 256 Tumor-Bearing Rats.

    PubMed

    Schiessel, Dalton Luiz; Yamazaki, Ricardo K; Kryczyk, Marcelo; Coelho, Isabela; Yamaguchi, Adriana A; Pequito, Daniele C T; Brito, Gleisson A P; Borghetti, Gina; Fernandes, Luiz C

    2015-07-01

    Fish oil (FO) has been shown to affect cancer cachexia, tumor mass, and immunity cell. n-3 PUFA, specifically ?-linolenic fatty acid (ALA), has controversial effects. We investigated this in nontumor-bearing Wistar rats fed regular chow (C), fed regular chow and supplemented with FO or Oro Inca oil (OI), and Walker 256 tumor-bearing rats fed regular chow (W), fed regular chow and supplemented with FO (WFO) or OI (WOI). Rats were supplemented (1g/kg body weight/day) during 4 wk and then the groups tumor-bearing were inoculated with Walker 256 tumor cells suspension and 14 days later the animals were killed. WFO increased EPA fivefold and DHA 1.5-fold in the tumor tissue compared to W (P < 0.05). OI supplementation increased of threefold of ALA when compared to W (P < 0.05). Tumor mass in WFO and OI was of 2.3-fold lower, as well as tumor cell proliferation of 3.0-fold tumor tissue lipoperoxidation increased of 76.6% and cox-2 expression was 20% lower. Cachexia parameters were attenuate, blood glucose (25% higher), Triacylglycerolemia (50% lower), and plasma TNF-? (65% lower; P < 0.05) and IL-6 (62.5% lower). OI, rich in ALA, caused the same effect on cancer as those seen in FO. PMID:26011096

  5. Disparate requirements for the Walker A and B ATPase motifs ofhuman RAD51D in homologous recombination

    SciTech Connect

    Wiese, Claudia; Hinz, John M.; Tebbs, Robert S.; Nham, Peter B.; Urbin, Salustra S.; Collins, David W.; Thompson, Larry H.; Schild, David

    2006-04-21

    In vertebrates, homologous recombinational repair (HRR) requires RAD51 and five RAD51 paralogs (XRCC2, XRCC3, RAD51B, RAD51C, and RAD51D) that all contain conserved Walker A and B ATPase motifs. In human RAD51D we examined the requirement for these motifs in interactions with XRCC2 and RAD51C, and for survival of cells in response to DNA interstrand crosslinks. Ectopic expression of wild type human RAD51D or mutants having a non-functional A or B motif was used to test for complementation of a rad51d knockout hamster CHO cell line. Although A-motif mutants complement very efficiently, B-motif mutants do not. Consistent with these results, experiments using the yeast two- and three-hybrid systems show that the interactions between RAD51D and its XRCC2 and RAD51C partners also require a functional RAD51D B motif, but not motif A. Similarly, hamster Xrcc2 is unable to bind to the non-complementing human RAD51D B-motif mutants in co-immunoprecipitation assays. We conclude that a functional Walker B motif, but not A motif, is necessary for RAD51D's interactions with other paralogs and for efficient HRR. We present a model in which ATPase sites are formed in a bipartite manner between RAD51D and other RAD51 paralogs.

  6. Changes in a cerebellar peduncle lesion in a patient with Dandy-Walker malformation: A diffusion tensor imaging study?

    PubMed Central

    Lee, Ah Young; Jang, Sung Ho; Yeo, Sang Seok; Lee, Ensil; Cho, Yun Woo; Son, Su Min

    2013-01-01

    We report a patient with severe ataxia due to Dandy-Walker malformation, who showed functional recovery over 10 months corresponding to a change in a cerebellar peduncle lesion. A 20-month-old female patient who was diagnosed with Dandy-Walker syndrome and six age- and sex-matched healthy control subjects were enrolled. The superior cerebellar peduncle, the middle cerebellar peduncle, and the inferior cerebellar peduncle were evaluated using fractional anisotropy and the apparent diffusion coefficient. The patients’ functional ambulation category was 0 at the initial visit, but improved to 2 at the follow-up evaluation, and Berg's balance scale score also improved from 0 to 7. Initial diffusion tensor tractography revealed that the inferior cerebellar peduncle was not detected, that the fractional anisotropy of the superior cerebellar peduncle and middle cerebellar peduncle decreased by two standard deviations below, and that the apparent diffusion coefficient increased by two standard deviations over normal control values. However, on follow-up diffusion tensor tractography, both inferior cerebellar peduncles could be detected, and the fractional anisotropy of superior cerebellar peduncle increased to within two standard deviations of normal controls. The functional improvement in this patient appeared to correspond to changes in these cerebellar peduncles. We believe that evaluating cerebellar peduncles using diffusion tensor imaging is useful in cases when a cerebellar peduncle lesion is suspected. PMID:25206690

  7. Relationships of pinon juniper woodland expansion and climate trends in the Walker Basin, Nevada

    NASA Astrophysics Data System (ADS)

    Donald, Jonathon

    Landscapes are in constant flux. Vegetation distributions have changed in conjunction with climate, driven by factors such as Milankovitch cycles and atmospheric composition. Until recently, these changes have occurred gradually. Human populations are altering Earth's systems, including atmospheric composition and land use. This is altering vegetation distributions at landscape scales due to changes in species potential niche, as well as current and historical alteration of their realized niche. Vegetation shifts have the potential to be more pronounced in arid and mountainous environments as resources available to plants such as soil moisture are more limiting. In the Great Basin physiographic region of the western United States, woody encroachment of pinon juniper (Pinus monophylla & Juniperus osteosperma) woodlands is well known, but the drivers of its expansion are not well understood across elevational gradients. Predominant theories of future vegetation distribution change due to a changing climate, predict that montane species will move upslope in response to increasing temperatures. In pinon juniper woodlands, the focus has been on downslope movement of woodlands into other ecosystem types. The drivers for this are typically thought to be historical land uses such as grazing and fire exclusion. However, infilling and establishment is occurring throughout its distribution and relatively little attention has been paid to woodland movement uphill. This study focuses on two mountain ranges within the Walker Lake Basin, so as to understand changes occurring along the full gradient of pinon juniper woodlands, from lower to upper treeline, on both the western and eastern side of the ranges. The overall goal of this study was to understand trends of change (increasing, decreasing canopy density) in pinon juniper woodlands and determine if these trends were related to climate change trends. Trends in both vegetation and climate were analyzed for the entire distribution of pinon juniper within the study area, and aggregated by ecologically pertinent zones of woodlands. Climate is highly variable and difficult to accurately represent at fine spatial scales, so aggregation to pertinent zones such as lower ecotones, upper ecotones, and main distribution of woodlands, allowed for meaningful inferences of how the amount of change among climatic variables over time were related to densification of pinon juniper canopy. The Mann-Kendall test of trend is able to detect trends in time series stacks of spectral vegetation indexes and discern between both large and small magnitude trends. Within the study area, pinon juniper woodlands showed the greatest increases in canopy density at upper ecotones, followed by lower ecotones. The amount of change corresponds to an increase of about 25% in canopy density over the 30 year time period in the upper ecotones, and about 18% increase at lower ecotones. Larger change at the upper ecotone suggests that pinon juniper is responding to climatic change in line with theories of vegetation response to climate. This is best explained by small increases in winter precipitation and larger increases in minimum temperature. These conditions would favor increased canopy by promoting seedling establishment. Weaker correlations with changes in climatic variables at the lower ecotone suggest that other factors, especially historic land use effects, are likely influencing pinon juniper to a greater degree. This follows others findings concerning encroachment, but suggests that the amount of change among climatic variables directly relates to overall rates of establishment and increasing canopy density. Encroachment at the lower bound of pinon juniper distribution is likely a response to artificial reduction of the realized niche.

  8. Seasonal Nutrient Dynamics of Foliage and Litterfall on Walker Branch Watershed, a Deciduous Forest Ecosystem

    SciTech Connect

    Grizzard, T. Henderson, G.S. Clebsch, E.

    1999-01-01

    A detailed twelve-month study of litterfall, live foliage biomass, and seasonal nutrient (nitrogen, phosphorus, potassium, calcium, sodium, and magnesium) dynamics in tree components was performed for forest types on Walker Branch Watershed, Oak Ridge, Tennessee. Biomass and nutrient content of foliage, reproductive parts and branches were examined for ten dominant trees in order to assess the relative importance of litterfall in returning nutrients to the forest floor in four different forest types. Litterfall, measured in pine, pine-oak-hickory, oak-hickory, and mesophytic hardwood forests, was separated into three components (leaves, reproductive parts, and branches). Seasonal comparisons of those forest types were made for biomass and nutrient inputs for each component and for total litterfall. Each forest types was characterized by total annual input to the forest floor of biomass and individual nutrients for each component as well as total litterfall. Canonical analysis was performed on the yearly totals to test for significant differences among the forest types. Live foliage from the ten predominant species of trees on the watershed, determined by order of total basal area, was analyzed for biomass, nutrient concentration, and changes in nutrient content through the growth season. Seasonal trends for these variables, including the ranking of nutrient concentrations for spring versus fall, were discussed in relation to differential growth, translocation, and leaching factors. Most of the litterfall in all forest types (77-85%) was in leaves with fall maximum. Reproductive parts (8-14% with spring and fall maxima) and branches (8-11% with no seasonal trend) contributed the remainder. The ranking of nutrient content in litterfall was similar in spring and fall, except for the replacement of nitrogen by calcium in autumn as the predominant nutrient (followed by K > Mg > P > Na). Comparisons were made between weight and nutrient content for living leaves and leaf litter input in litterfall. The ranking of total nutrient content per leaf in spring foliage was N > K > Ca > Mg > P > Na. The autumn foliage ranking was the same as that for autumn leaf litterfall (Ca > N > K > Mg > P > Na), the change being due to differing behavior of the particular nutrients (translocation, biomass dilution and removal by leaching). In the four forest types analyzed, significant differences occurred in the biomass and individual nutrients recycled to the forest floor. The greatest litterfall and amounts of nitrogen input occurred in the pine forest type. Oak-hickory forests had the greatest litter inputs of magnesium and potassium. Calcium return was greatest in the mesophytic hardwood forest. No marked differences in the amounts of sodium and phosphorus return in the forest floor occurred among mesophytic hardwoods and oak-hickory forest types, which were consistently higher than pine and pine-oak-hickory forest values.

  9. Magmatic-Tectonic Interactions: Implications for Seismic Hazard Assessment in the Central Walker Lane and Long Valley Caldera Regions

    NASA Astrophysics Data System (ADS)

    Chacko, R.; Hammond, W. C.; Blewitt, G.; Bormann, J. M.

    2014-12-01

    Accurate estimates of fault slip rates based on geodetic data rely on measurements that represent the long-term deformation of the crust. In the Central Walker Lane/Sierra Nevada transition, the Long Valley Caldera region has experienced multiple episodes of uplift and subsidence during the last four decades. The latest episode began in late 2011 and is detectable as a transient signal in the time series of GPS stations around the caldera. These transient signals become more apparent and reveal the extent of the impact on the ambient crustal deformation field of the Walker Lane when the velocity vectors are transformed to a Sierra-Nevada reference frame. Estimating contemporary slip-rates on faults for the purpose of seismic hazard assessment in the region around Long Valley requires detecting and subtracting the transient signals caused by the uplift and subsidence in the caldera. We estimate the geographic extent to which the ambient crustal deformation field is significantly perturbed by ongoing magmatic activity in Long Valley. We present a time variable 3D deformation field constrained by InSAR and GPS observations, and discuss the implications that tectonic-magmatic interaction have for estimates of present-day fault slip-rate. We model the time dependent deformation at Long Valley by analyzing InSAR time series from Envisat and ERS interferograms spanning a period of more than 19 years. We use an analytical volcano deformation source model derived from vertical (GPS) and line of site (InSAR) component of geodetic observations to estimate the horizontal component of the signals associated with magmatic activity beneath the caldera. Previous studies showed that the latest episode of uplift can be modeled with a Mogi source located at a depth of ~6 km with a volume change of 0.03 km3 beneath the resurgent dome. This model predicts a perturbation to the ambient crustal deformation field extending as far as 60 km from the center of the resurgent dome. Thus the area affected by Long Valley extends from north of Mono Lake southward to Owens Lake, and eastward to the Mina deflection of the Walker Lane, potentially influencing the estimated slip rates for a dozen or more major faults.

  10. Abstract--This paper presents MoonWalker, a lower limb exoskeleton able to sustain part of a user's bodyweight. This

    E-print Network

    Boyer, Edmond

    Abstract-- This paper presents MoonWalker, a lower limb exoskeleton able to sustain part of a user improving energetic autonomy of lower limb exoskeletons. Keywords-- Exoskeleton, orthosis, passive force balancer. I. INTRODUCTION ESEARCH in actuated exoskeleton devices began truly in the late 1960s [1

  11. Light modulation at molecular frequencies A. V. Sokolov, D. D. Yavuz, D. R. Walker, G. Y. Yin, and S. E. Harris

    E-print Network

    Yavuz, Deniz

    Light modulation at molecular frequencies A. V. Sokolov, D. D. Yavuz, D. R. Walker, G. Y. Yin 7 June 2000; published 16 April 2001 We describe the generation of amplitude- and frequency-modulated light with a modulation frequency equal to the fundamental vibrational frequency of molecular deuterium

  12. The Delta Q Method of Testing the Air Leakage of Ducts Walker, I.S., Dickerhoff, D.J. and Sherman, M.H.

    E-print Network

    LBNL-49749 The Delta Q Method of Testing the Air Leakage of Ducts Walker, I.S., Dickerhoff, D.J. and Sherman, M.H. Indoor Environment Department Lawrence Berkeley National Laboratory ABSTRACT The DeltaQ test in energy efficiency calculations and for compliance testing of duct systems. The DeltaQ test combines

  13. A Circuit Level Fault Model for Resistive Bridges ZHUO LI, XIANG LU, WANGQI QIU, WEIPING SHI and D. M. H. WALKER

    E-print Network

    Walker, Duncan M. "Hank"

    A Circuit Level Fault Model for Resistive Bridges ZHUO LI, XIANG LU, WANGQI QIU, WEIPING SHI and D. M. H. WALKER Texas A&M University Delay faults are an increasingly important test challenge. Modeling bridge faults as delay faults helps delay tests to detect more bridge faults. Traditional bridge

  14. Ressorts en alliage de titane M. Peter (1), E. Walker (1), E. Frei (2), O. Pohler (2) et S. Steinemann (3)

    E-print Network

    Boyer, Edmond

    2433 Ressorts en alliage de titane M. Peter (1), E. Walker (1), E. Frei (2), O. Pohler (2) et S alliages habituellement utilisés dans la fabrication du ressort-moteur par des alliages de titane qui ont titane, grâce à son module de Young réduit, permet d'améliorer la durée et l'uniformité de la marche du

  15. A Phase I Archaeological Survey of a 14.125 Acre Tract: The Arbors of Sam Houston Housing Project in Central Walker County, Texas

    E-print Network

    Moore, William; Wagner, Janet

    2015-06-09

    A Phase Iarcheological assessment of a 14.125 acre tract in central Walker County,Texas was performed in March 1998 by Brazos Valley Research Associates (BVRA) of Bryan, Texas. This is a federal project regulated by the Housing and Urban Development...

  16. Walker Gilmore: a stratified Woodland period occupation in eastern Nebraska. A report of the 1968 excavations. Final report 1968-83

    Microsoft Academic Search

    Haas

    1983-01-01

    Excavations at Walker Gilmore were designed to test the ill-defined concept of 'Sterns Creek culture' in the Central Plains subarea. Five Woodland period levels produced evidence for 48 tool classes, flora and fauna, and 762 features including structural remains. Level 1 is poorly recorded and relatively unknown. Levels 2 - 4 contain abundant evidence of subsistence, structure, and settlement. Broad

  17. Paleomagnetic Data Bearing on the Evolution of the Walker Lane Belt Transfer Zone From mid-Miocene to Present: an Investigation of the Inferred Southern and Eastern Boundaries

    Microsoft Academic Search

    J. S. Grow; J. W. Geissman; J. S. Oldow

    2008-01-01

    The Walker Lane Belt (WLB) transfer zone, which initiated in the mid-Miocene, presently links the Eastern California Shear Zone (ECSZ) in the south to the Central Nevada Seismic Belt (CNSB) and WLB to the east and north, respectively. This transfer zone is part of a diffuse intracontinental deformation zone that accommodates some 25 percent of the current motion between the

  18. Collecting at night at the old porch light: Discovery of the light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), in North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The light brown apple moth (LBAM), Epiphyas postvittana (Walker), is a highly polyphagous species that is an important pest of apple and citrus in many parts of the world, primarily Australia and New Zealand. The potential threat of LBAM to North American agriculture was recognized formally in 1957 ...

  19. Magnetic Resonance Imaging Diagnosis of Dandy-Walker-Like Syndrome in a Wire-Haired Miniature Dachshund

    PubMed Central

    KOBATAKE, Yui; MIYABAYASHI, Takayoshi; YADA, Naoko; KACHI, Shingo; OHTA, George; SAKAI, Hiroki; MAEDA, Sadatoshi; KAMISHINA, Hiroaki

    2013-01-01

    ABSTRACT A 12-week-old female Wire-haired miniature dachshund presented with non-progressive ataxia and hypermetria. Due to the animal’s clinical history and symptoms, cerebellar malformations were suspected. Computed tomography (CT) and magnetic resonance imaging (MRI) detected bilateral ventriculomegaly, dorsal displacement of the cerebellar tentorium, a defect in the cerebellar tentorium and a large fluid-filled cystic structure that occupied the regions where the cerebellar vermis and occipital lobes are normally located. The abovementioned cystic structure and the defect in the cerebellar tentorium were comparable to those seen in humans with Dandy-Walker syndrome. However, the presence of the cystic structure in the occipital lobe region was unique to the present case. During necropsy, the MRI findings were confirmed, but the etiology of the condition was not determined. PMID:23719692

  20. One-loop {lambda}{phi}{sup 4} field theory in Robertson-Walker spacetimes: Adiabatic regularization and analytic approximations

    SciTech Connect

    Molina-Paris, Carmen [Theoretical Division T-8, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Anderson, Paul R. [Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109 (United States); Theoretical Division T-8, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ramsey, Stephen A. [Genome Center, University of Washington, Seattle, Washington 98195-2145 (United States)

    2000-06-15

    We study a scalar field with quartic self-coupling in a Robertson-Walker spacetime at one-loop order. A variation of the adiabatic regularization method is presented which leads to analytic approximations for the quantum energy-momentum tensor and the quantum contribution to the effective mass of the mean field. Conservation of the energy-momentum tensor for the field is discussed and it is shown that the full renormalized energy-momentum tensor is conserved as expected and required by the semiclassical Einstein's equation. It is also shown that if the analytic approximations are used, then the resulting approximate energy-momentum tensor is conserved. (c) 2000 The American Physical Society.

  1. Analog model of a Friedmann-Robertson-Walker universe in Bose-Einstein condensates: Application of the classical field method

    SciTech Connect

    Jain, Piyush; Weinfurtner, Silke; Visser, Matt; Gardiner, C. W. [School of Chemical and Physical Sciences, Victoria University of Wellington (New Zealand); School of Mathematics, Statistics, and Computer Science, Victoria University of Wellington (New Zealand); Jack Dodd and Dan Walls Centre for Photonics and Ultra Cold Atoms, Department of Physics, Otago University, Dunedin (New Zealand)

    2007-09-15

    Analog models of gravity have been motivated by the possibility of investigating phenomena not readily accessible in their cosmological counterparts. In this paper, we investigate the analog of cosmological particle creation in a Friedmann-Robertson-Walker universe by numerically simulating a Bose-Einstein condensate with a time-dependent scattering length. In particular, we focus on a two-dimensional homogeneous condensate using the classical field method via the truncated Wigner approximation. We show that for various forms of the scaling function the particle production is consistent with the underlying theory in the long wavelength limit. In this context, we further discuss the implications of modified dispersion relations that arise from the microscopic theory of a weakly interacting Bose gas.

  2. Towards a better understanding of the impacts of climate change on agricultural productivity and economics in the Walker River Basin

    NASA Astrophysics Data System (ADS)

    Wilson, C. J.; Boyle, D. P.; Garner, C.; Bassett, S.

    2014-12-01

    A significant decrease in seasonal precipitation and a general increase in air temperature over the last three years have resulted in extreme to exceptional drought conditions in much of the southwestern U.S., where water resources are becoming scarcer. In many cases, the impacts of the drought on the agricultural productivity has been severe, as farmers have struggled to maintain the crop water requirements with limited resources available from surface water deliveries and groundwater pumping. In this study, we aim to identify the impacts of climate change on agricultural productivity in the Walker River Basin. In order to develop a better understand of the regional agricultural economic impacts and potential mitigation strategies, we quantify the value of surface water along with supplemental groundwater pumping. Specifically, we analyze changes in potential crop production (both quantity and revenue) and the associated conjunctive use of available surface water and groundwater in both dry and warm climates.

  3. Quantization of Friedmann-Robertson-Walker spacetimes in the presence of a negative cosmological constant and radiation

    SciTech Connect

    Monerat, G.A.; Silva, E.V. Correa; Oliveira-Neto, G. [Departamento de Matematica e Computacao, Faculdade de Tecnologia, Universidade do Estado do Rio de Janeiro, Estrada Resende-Riachuelo, s/no, Morada da Colina, CEP 27523-000, Resende-RJ (Brazil); Filho, L.G. Ferreira [Departamento de Mecanica e Energia, Faculdade de Tecnologia, Universidade do Estado do Rio de Janeiro, Estrada Resende-Riachuelo, s/no, Morada da Colina, CEP 27523-000 , Resende-RJ (Brazil); Lemos, N.A. [Instituto de Fisica, Universidade Federal Fluminense, R. Gal. Milton Tavares de Souza s/no, Boa Viagem, CEP 24210-340, Niteroi-RJ (Brazil)

    2006-02-15

    In the present work, we quantize three Friedmann-Robertson-Walker models in the presence of a negative cosmological constant and radiation. The models differ from each other by the constant curvature of their spatial sections, which may be positive, negative or zero. They give rise to Wheeler-DeWitt equations for the scale factor which have the form of the Schroedinger equation for the quartic anharmonic oscillator. We find their eigenvalues and eigenfunctions by using a method first developed by Chhajlany and Malnev. After that, we use the eigenfunctions in order to construct wave packets for each case and evaluate the time-dependent expectation value of the scale factors, which are found to oscillate between finite maximum and minimum values. Since the expectation values of the scale factors never vanish, we have an initial indication that these models may not have singularities at the quantum level.

  4. Evaluation of geodetic and geologic datasets in the Northern Walker Lane-Summary and recommendations of the Workshop

    USGS Publications Warehouse

    Briggs, Richard W.; Hammond, William C.

    2010-01-01

    The Northern Walker Lane comprises a complex network of active faults in northwestern Nevada and northeastern California bound on the west by the Sierra Nevada and on the east by the extensional Basin and Range Province. Because deformation is distributed across sets of discontinuous faults, it is particularly challenging to integrate geologic and geodetic data in the NWL to assess the region's seismic hazard. Recent GPS measurements show that roughly one centimeter per year of relative displacement is accumulating across a zone about 100 km wide at the latitude of Reno, Nevada, but it is not clear where or how much of this strain might ultimately be released in damaging earthquakes. Despite decades of work in the region, the sum of documented late Pleistocene to recent slip rates is distinctly less than the GPS-measured relative displacement.

  5. Plant-growth response to various combinations of mulches and spoil substrates on a Walker County, Alabama, surface coal mine

    SciTech Connect

    Cross, E.A.; Gabrielson, F.C.; Hughes, T.H.

    1982-05-01

    In 1978-1979, Walker County, Alabama, was the site of an experiment designed to assess plant growth and soil erosion. The experiment utilized 6 mulch treatments applied to each of 3 coal surface mine substrates. The mulches (wood fiber, hardwood bark, pine bark, waste compost, paper-slag, and no mulch application) were randomly combined with either A + B horizon soil, shale, or a mixture of the two. The resulting 18 plots were replicated on two slopes (N-S). A standard seed-fertilizer regimen was applied to all plots. Plots were read in June and October 1979 for species composition, density, and plane cover. Overall grass growth, as measured by plane cover, was best on mixed substrate, and growth was not significantly different between shale and topsoil plots. Density and cover provided by volunteer species varied according to slope, substrate, and mulch combinations. Overall, numbers of spoil arthropods did not show great differences according to slope or substrate.

  6. Hydrologic model based on deep test data from the Walker O No. 1 well, Terminal Geyser, California

    SciTech Connect

    Beall, J.J.

    1981-10-01

    The Shasta Forest No. 1 Well (renamed Walker O No. 1) at Terminal Geyser, California, was reentered and deepened from 1258 to 4008 feet. Temperature logs indicate the well penetrated a laterally flowing thermal aquifer between 1400 and 2200 feet. Large amounts of drilling fluids were lost in that zone. Maximum temperature in the well (10 months after drilling) was 348/sup 0/F at 2000 feet. A large reversed temperature gradient zone occurs below 2400 feet. Bottom hole temperature is 256/sup 0/F. After completion, the well was flowed for about five hours with nitrogen injection at 2000 feet. Samples taken throughout the flow indicate that fluids lost during drilling were not completely recovered. Salinity increased steadily during the flow period. Ratios of Na, K, and Ca were nearly constant, however, and application of Na-K and Na-K-Ca geothermometers indicate these fluids were in equilibrium with rocks at a temperature of 448-449/sup 0/F.

  7. An interaction between the Walker A and D-loop motifs is critical to ATP hydrolysis and cooperativity in bacteriophage T4 Rad50.

    PubMed

    De la Rosa, Metzere Bierlein; Nelson, Scott W

    2011-07-22

    The ATP binding cassette (ABC) proteins make up a large superfamily with members coming from all kingdoms. The functional form of the ABC protein nucleotide binding domain (NBD) is dimeric with ATP binding sites shared between subunits. The NBD is defined by six motifs: the Walker A, Q-loop, Signature, Walker-B, D-loop, and H-loop. The D-loop contains a conserved aspartate whose function is not clear but has been proposed to be involved in cross-talk between ATP binding sites. Structures of various ABC proteins suggest an interaction between the D-loop aspartate and an asparagine residue located in Walker A loop of the opposing subunit. Here, we evaluate the functional role of the D-loop using a bacteriophage T4 ABC protein, Rad50 (gp46). Mutation of either the D-loop aspartate or the Walker A asparagine results in dramatic reductions in ATP affinity, hydrolysis rate, and cooperativity. The mutant proteins bind Mre11 (gp47) and DNA normally, but no longer support the ATP-dependent nuclease activities of Mre11. We propose that the D-loop aspartate functions to stabilize the Walker A asparagine in a position favorable for catalysis. We find that the asparagine is crucially important to the mechanism of ATP hydrolysis by increasing the affinity for ATP and positioning the ?-phosphate of ATP for catalysis. Additionally, we propose that the asparagine acts as a ?-phosphate sensor and, through its interaction with the conserved D-loop aspartate, transmits conformational changes across the dimer interface to the second ATP binding site. PMID:21610075

  8. How Do Ants Make Sense of Gravity? A Boltzmann Walker Analysis of Lasius niger Trajectories on Various Inclines

    PubMed Central

    Khuong, Anaïs; Lecheval, Valentin; Fournier, Richard; Blanco, Stéphane; Weitz, Sébastian; Bezian, Jean-Jacques; Gautrais, Jacques

    2013-01-01

    The goal of this study is to describe accurately how the directional information given by support inclinations affects the ant Lasius niger motion in terms of a behavioral decision. To this end, we have tracked the spontaneous motion of 345 ants walking on a 0.5×0.5 m plane canvas, which was tilted with 5 various inclinations by rad ( data points). At the population scale, support inclination favors dispersal along uphill and downhill directions. An ant's decision making process is modeled using a version of the Boltzmann Walker model, which describes an ant's random walk as a series of straight segments separated by reorientation events, and was extended to take directional influence into account. From the data segmented accordingly ( segments), this extension allows us to test separately how average speed, segments lengths and reorientation decisions are affected by support inclination and current walking direction of the ant. We found that support inclination had a major effect on average speed, which appeared approximately three times slower on the incline. However, we found no effect of the walking direction on speed. Contrastingly, we found that ants tend to walk longer in the same direction when they move uphill or downhill, and also that they preferentially adopt new uphill or downhill headings at turning points. We conclude that ants continuously adapt their decision making about where to go, and how long to persist in the same direction, depending on how they are aligned with the line of maximum declivity gradient. Hence, their behavioral decision process appears to combine klinokinesis with geomenotaxis. The extended Boltzmann Walker model parameterized by these effects gives a fair account of the directional dispersal of ants on inclines. PMID:24204636

  9. Role of highly central residues of P-loop and it's flanking region in preserving the archetypal conformation of Walker A motif of diverse P-loop NTPases.

    PubMed

    Pathak, Ekta; Atri, Neelam; Mishra, Rajeev

    2013-01-01

    P-loop NTPases represent a large and highly diverse protein family that is involved in variety of cellular functions. Walker A motif forms a typical arched conformation, necessary to accommodate the phosphate moiety of the nucleoside tri (or di-) phosphate in Ploop NTPases. The feature that maintains the ancient architecture of P-loop is unidentified and uncharacterized. Here, using a well established global network parameter, closeness centrality, we identify that Walker A and its flanking regions (N- and C-terminal) have high density of globally connected residue positions. We find that closeness centrality of these residue positions are conserved across common structural core of diverse domains of P-loop NTPase fold. Our results suggest the potential role of globally connected residues in maintaining the local conformation of P-loop. PMID:23390340

  10. Glucose metabolism by lymphocytes, macrophages, and tumor cells from Walker 256 tumor-bearing rats supplemented with fish oil for one generation.

    PubMed

    Aikawa, Júlia; Moretto, Karla D; Denes, Francilene; Yamazaki, Ricardo K; Freitas, Fábio A P; Hirabara, Sandro M; Tchaikovski, Osvaldo; Kaelher, Marcos de A; Brito, Gleysson A P; Curi, Rui; Fernandes, Luiz C

    2008-12-01

    Here we investigated the effect of lifelong supplementation of the diet with coconut fat (CO, rich in saturated fatty acids) or fish oil (FO, rich in n-3 polyunsaturated fatty acids) on tumor growth and lactate production from glucose in Walker 256 tumor cells, peritoneal macrophages, spleen, and gut-associated lymphocytes. Female Wistar rats were supplemented with CO or FO prior to mating and then throughout pregnancy and gestation and then the male offspring were supplemented from weaning until 90 days of age. Then they were inoculated subcutaneously with Walker 256 tumor cells. Tumor weight at 14 days in control rats (those fed standard chow) and CO supplemented was approximately 30 g. Supplementation of the diet with FO significantly reduced tumor growth by 76%. Lactate production (nmol h(-1) mg(-1) protein) from glucose by Walker 256 cells in the group fed regular chow (W) was 381.8 +/- 14.9. Supplementation with coconut fat (WCO) caused a significant reduction in lactate production by 1.6-fold and with fish oil (WFO) by 3.8-fold. Spleen lymphocytes obtained from W and WCO groups had markedly increased lactate production (553 +/- 70 and 635 +/- 150) when compared to non-tumor-bearing rats ( approximately 260 +/- 30). FO supplementation reduced significantly the lactate production (297 +/- 50). Gut-associated lymphocytes obtained from W and WCO groups increased lactate production markedly (280 +/- 31 and 276 +/- 25) when compared to non-tumor-bearing rats ( approximately 90 +/- 18). FO supplementation reduced significantly the lactate production (168 +/- 14). Lactate production by peritoneal macrophages was increased by tumor burden but there was no difference between the groups fed the various diets. Lifelong consumption of FO protects against tumor growth and modifies glucose metabolism in Walker tumor cells and lymphocytes but not in macrophages. PMID:18946876

  11. Two-Dimensional Gel Electrophoresis of Acid-extractable Nuclear Proteins of Regenerating and Thioacetamide-treated Rat Liver, Morris 9618A Hepatoma, and Walker 256 Carcinosarcoma1

    Microsoft Academic Search

    Lynn C. Yeoman; Charles W. Taylor; Harris Busch

    SUMMARY The acid-soluble nuclear proteins of regenerating and thi- oacetamide-treated rat livers as well as the Morris 9618A hepatoma and the Walker 256 carcinosarcoma were ex tracted from citric acid-isolated nuclei with 0.4 N H2SO4. The nuclear extracts were analyzed by two-dimensional polyacrylamide gel electrophoresis. Although most of the protein spots were common to the livers and tumors stud ied,

  12. Centre Te Ao Tamariki Early Childhood Learning Centre Sheila Walker Unit ChiLd'S NAmE/TE iNgoA o T TAmAiTi

    E-print Network

    Hickman, Mark

    TAmAiTi Sex Female/Kotiro male/Tane date of birth/Te rä whänau Child's address/Kainga NAmE oF pCentre Te Ao Tamariki Early Childhood Learning Centre Sheila Walker Unit ChiLd'S NAmE/TE iNgoA o TÖ other people who may collect you child please list anyone who is forbidden to have access to your child

  13. Baby walker injury awareness among grade-12 girls in a high-prevalence Arab country in the Middle East.

    PubMed

    Grivna, Michal; Barss, Peter; Al-Hanaee, Amna; Al-Dhahab, Ayesha; Al-Kaabi, Fatima; Al-Muhairi, Shamma

    2015-03-01

    Baby walkers (BWs) are a consumer product frequently associated with infant injuries. With little research in the Middle East and few population studies anywhere, female students in grade 12 in the United Arab Emirates were surveyed, assessing the prevalence of use, perceived safety, and interventions. The study population included grade-12 students in a large UAE city. Multistage random sampling selected 4/8 female Arab government schools and 3 classes each from science and arts tracks for interview by self-administered questionnaire. Response was 100%, with a total of 696 students, 55% (n = 385) of whom were Emirati citizens; 90% (n = 619) of the families used/had used BWs. Among the reasons for use, 92% reported "keeping baby safe," with 11% perceiving BWs as very safe and 74% as moderately safe. Only 16% perceived that BWs could cause injuries. Despite causing many injuries, including fatalities, BWs were perceived to be safe and used by nearly all families. Effective education of professionals, patients, the public, and decision makers is needed. Governments should consider countermeasures such as prohibiting importation, sales, and advertising, together with public education and provision of stationary activity centers. PMID:24595658

  14. Dual-task effects of spontaneous speech and executive function on gait in aging: exaggerated effects in slow walkers.

    PubMed

    Plummer-D'Amato, Prudence; Altmann, Lori J P; Reilly, Kevin

    2011-02-01

    This study compared the effects of spontaneous speech and executive function on gait and investigated the effects of single-task gait speed on dual-task costs. Twenty-one older adults (74.7 years, SD 5.9) and 23 younger adults (22 years, SD 1.2) walked for 60s while performing an auditory Stroop task and a spontaneous speech task; they also performed each task in isolation. Walking while talking significantly reduced gait speed in both groups; however, only older adults experienced significant cognitive-motor interference during the Stroop task. Stride duration variability and gait symmetry were also affected by the speech task in older but not younger adults. Dual-task costs on gait speed were greater in slow-walking older adults than fast walkers. These results demonstrate that spontaneous speech is a highly demanding task that has a profound impact on gait in older adults, especially those with gait speed <1 m/s. PMID:21193313

  15. Cosmology of a Friedmann-Lamaître-Robertson-Walker 3-brane, late-time cosmic acceleration, and the cosmic coincidence.

    PubMed

    Doolin, Ciaran; Neupane, Ishwaree P

    2013-04-01

    A late epoch cosmic acceleration may be naturally entangled with cosmic coincidence--the observation that at the onset of acceleration the vacuum energy density fraction nearly coincides with the matter density fraction. In this Letter we show that this is indeed the case with the cosmology of a Friedmann-Lamaître-Robertson-Walker (FLRW) 3-brane in a five-dimensional anti-de Sitter spacetime. We derive the four-dimensional effective action on a FLRW 3-brane, from which we obtain a mass-reduction formula, namely, M(P)(2) = ?(b)/|?(5)|, where M(P) is the effective (normalized) Planck mass, ?(5) is the five-dimensional cosmological constant, and ?(b) is the sum of the 3-brane tension V and the matter density ?. Although the range of variation in ?(b) is strongly constrained, the big bang nucleosynthesis bound on the time variation of the effective Newton constant G(N) = (8?M(P)(2))(-1) is satisfied when the ratio V/? ? O(10(2)) on cosmological scales. The same bound leads to an effective equation of state close to -1 at late epochs in accordance with astrophysical and cosmological observations. PMID:25166976

  16. Cosmology of a Friedmann-Lamaître-Robertson-Walker 3-Brane, Late-Time Cosmic Acceleration, and the Cosmic Coincidence

    NASA Astrophysics Data System (ADS)

    Doolin, Ciaran; Neupane, Ishwaree P.

    2013-04-01

    A late epoch cosmic acceleration may be naturally entangled with cosmic coincidence—the observation that at the onset of acceleration the vacuum energy density fraction nearly coincides with the matter density fraction. In this Letter we show that this is indeed the case with the cosmology of a Friedmann-Lamaître-Robertson-Walker (FLRW) 3-brane in a five-dimensional anti-de Sitter spacetime. We derive the four-dimensional effective action on a FLRW 3-brane, from which we obtain a mass-reduction formula, namely, MP2=?b/|?5|, where MP is the effective (normalized) Planck mass, ?5 is the five-dimensional cosmological constant, and ?b is the sum of the 3-brane tension V and the matter density ?. Although the range of variation in ?b is strongly constrained, the big bang nucleosynthesis bound on the time variation of the effective Newton constant GN=(8?MP2)-1 is satisfied when the ratio V/??O(102) on cosmological scales. The same bound leads to an effective equation of state close to -1 at late epochs in accordance with astrophysical and cosmological observations.

  17. Exploring the Midgut Transcriptome and Brush Border Membrane Vesicle Proteome of the Rice Stem Borer, Chilo suppressalis (Walker)

    PubMed Central

    Peng, Chuanhua; Wang, Xiaoping; Li, Fei; Lin, Yongjun

    2012-01-01

    The rice stem borer, Chilo suppressalis (Walker) (Lepidoptera: Pyralidae), is one of the most detrimental pests affecting rice crops. The use of Bacillus thuringiensis (Bt) toxins has been explored as a means to control this pest, but the potential for C. suppressalis to develop resistance to Bt toxins makes this approach problematic. Few C. suppressalis gene sequences are known, which makes in-depth study of gene function difficult. Herein, we sequenced the midgut transcriptome of the rice stem borer. In total, 37,040 contigs were obtained, with a mean size of 497 bp. As expected, the transcripts of C. suppressalis shared high similarity with arthropod genes. Gene ontology and KEGG analysis were used to classify the gene functions in C. suppressalis. Using the midgut transcriptome data, we conducted a proteome analysis to identify proteins expressed abundantly in the brush border membrane vesicles (BBMV). Of the 100 top abundant proteins that were excised and subjected to mass spectrometry analysis, 74 share high similarity with known proteins. Among these proteins, Western blot analysis showed that Aminopeptidase N and EH domain-containing protein have the binding activities with Bt-toxin Cry1Ac. These data provide invaluable information about the gene sequences of C. suppressalis and the proteins that bind with Cry1Ac. PMID:22666467

  18. Does freezing and dynamic flexing of frozen branches impact the cavitation resistance of Malus domestica and the Populus clone Walker?

    PubMed

    Christensen-Dalsgaard, Karen K; Tyree, Melvin T

    2013-11-01

    Frost damage to the xylem conduits of trees is a phenomenon of eco-physiological importance. It is often documented in terms of the percentage loss of conductivity (PLC), an indicator of air filling of the conduits. However, trees that refill their conduits in spring could be impacted more by damage to the conduits that reduce cavitation resistance, making them more susceptible to future drought events. We investigated whether ice formation, dynamic flexing of frozen branches or freeze-thaw events could reduce the cavitation resistance (cause "frost fatigue") in first-year shoots of apple (Malus domestica) and clonal hybrid cottonwood (Walker). Frost fatigue was measured in terms of P50 (the negative xylem pressure required to cause a 50 % loss of conductivity). All treatment groups showed significant frost fatigue, with the exception of the pre-flushed, constantly frozen poplar branches. The P50 following freeze treatments was approximately 50 % of the pre-freeze values. The effect tended to be greater in freeze-thawed branches. Dynamic bending of the branches had no effect on either PLC or P50. In three out of four cases, there was a significant correlation between P50 and PLC. Frost fatigue occurred in both apple and poplar, two unrelated species with different drought and frost tolerances, suggesting that it may be a widespread phenomenon that could impact the ecophysiology of temperate forests. PMID:23624704

  19. A rat model of bone cancer pain induced by intra-tibia inoculation of Walker 256 mammary gland carcinoma cells

    SciTech Connect

    Mao-Ying, Q.-L. [Department of Integrative Medicine and Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Zhao Jun [Institute of Neurobiology, Fudan University, Shanghai 200433 (China); Dong Zhiqiang [Department of Integrative Medicine and Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Wang Jun [Department of Integrative Medicine and Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Yu Jin [Department of Integrative Medicine and Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Yan Minfen [Institute of Radiation Medicine, Fudan University, Shanghai 200032 (China); Zhang Yuqiu [Institute of Neurobiology, Fudan University, Shanghai 200433 (China); Wu Gencheng [Department of Integrative Medicine and Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Wang Yanqing [Department of Integrative Medicine and Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032 (China) and Shanghai Research Center of Acupuncture and Meridian, Shanghai 201203 (China)]. E-mail: wangyanqing@shmu.edu.cn

    2006-07-14

    This study described a modified rat model of bone cancer pain. Syngeneic Walker 256 mammary gland carcinoma cells were injected into the tibia medullary cavity via intercondylar eminence. Series of tests were carried out including bone radiology, bone histology, ambulatory pain, thermal hyperalgesia, mechanical allodynia, weight bearing ability, and electrophysiological recording from primary afferent fibers. The rats inoculated with carcinoma cells showed significant ambulatory pain, mechanical allodynia, and reduction in weight bearing, as well as increased incidence of spontaneous activity in A{beta} fibers in affected limb, whereas PBS (vehicle) or heat-killed cells (sham) injected rats showed no significant difference in comparison to normal rats. The pain hypersensitive behaviors were aggravated with time and destruction of bone. Interestingly, mechanical allodynia was also observed in the contralateral limb, indicating the involvement of 'mirror image' pain in bone cancer pain. In summary, the present study provided a useful and easily established rat model of bone cancer pain which will contribute to further study of the mechanisms underlying cancer pain.

  20. Cloning, Expression and Purification of Subunit H of Vacuolar H+-ATPase from Mythimna separata Walker (Lepidoptera: Noctuidae)

    PubMed Central

    Lu, Lina; Qi, Zhijun; Wu, Wenjun

    2014-01-01

    The vacuolar (H+)-ATPase (V-ATPase) of insect, which is composed of membrane-bound V0 complex and peripheral V1 complex, participates in lots of important physiological process. Subunit H, as a subunit of V1 complex, plays a vital role in bridging the communication between V1 and V0 complexes and interaction with other proteins. Yeast subunit H has been successfully crystallized through expression in E. coli, but little is known about the structure of insect subunit H. In this study, we cloned, expressed and purified the subunit H from midgut of Mythimna separata Walker. Through RACE (rapidly amplification of cDNA ends) technique, we got 1807 bp full length of subunit H, and to keep the nature structure of subunit H, we constructed Baculovirus expression vector with His-tag in the C-terminal and expressed the recombinant protein in insect sf9 cells, thereafter, purified the recombinant protein by Ni-NTA columns. Results of SDS-PAGE, western blotting and mass spectrometry showed that the recombinant protein was successfully expressed. The method of expressing and purifying M. separata subunit H will provide a foundation for obtaining the crystal of subunit H and further study of the design of novel insecticides based on its structure and function. PMID:25257524

  1. Treatment of Walker ascites tumor cells by combination of photodynamic therapy with cyclophosphamide and interleukin-2 entrapped in liposomes

    NASA Astrophysics Data System (ADS)

    Dima, Vasile F.; Ionescu, Mircea D.; Balotescu, Carmen; Dima, V. S.

    2003-12-01

    The purpose of this study was to investigate the beneficial and adverse local effects of PDT associated with chemoimmunotherapy on rats bearing Walker ascites tumor cells. Experiments were performed on five batches of Wistar inbred rats with ascites tumor cells receiving intraperitoneally PDT (Photofrin II and 18 hrs later HeNe laser irradiation); Cyclophosphamide (CY); interleukin-2 (IL-2) or associated therapy (PDT+CY+IL-2). The control batch consisted of untreated rats (HBSS). The following results were noticed: (a) sole administration of PDT, IL-2 or CY reduced tumor growth, gave survival rates between 28.4 and 56.5% and cure rates ranging from 12.4 to 33.3%; (b) combined therapy (PDT+CY+IL-2) decreased tumor growth, increased survival rates (88.5%) and cure rates were 73.1% forty-two days post-transplantation. Summing up, in this study we noticed that PDT associated with chemoimmunotherapy reduced mortality as well as tumor volumes and increased cure rates in rats with ascites tumor cells. This approach points to the need for further evaluation in patients with peritoneal malignancies.

  2. Effects of Total Ginsenosides on the Feeding Behavior and Two Enzymes Activities of Mythimna separata (Walker) Larvae

    PubMed Central

    Zhang, Ai-Hua; Tan, Shi-Qiang; Zhao, Yan; Lei, Feng-Jie; Zhang, Lian-Xue

    2015-01-01

    Ginsenosides, the main effective components of Panax ginseng C.A. Meyer and Panax quinquefolius L., are important allelochemicals of ginseng. Although many studies have targeted the pharmacological, chemical, and clinical properties of ginsenosides, little is known about their ecological role in ginseng population adaptation and evolution. Pests rarely feed on ginseng, and it is not known why. This study investigated the effects of total ginsenosides on feeding behavior and activities of acetylcholinesterase (AChE) and glutathione s-transferase (GST) in Mythimna separata (Walker) larvae. The results showed that the total ginsenosides had significant antifeeding activity against M. separata larvae, determined by nonselective and selective antifeeding bioassays. In addition, the total ginsenosides had inhibitory effects on the activities of GST and AChE. The antifeeding ratio was the highest at 8?h, then decreased, and was the lowest at 16?h. Both GST and AChE activities decreased from 0?h to 48?h in all total ginsenosides treatments but increased at 72?h. Total ginsenosides had antifeeding activity against M. separata larvae and inhibitory effects on the activities of GST and AChE.

  3. Evidence for oil-induced oxidative stress to larvae of the lightbrown apple moth, Epiphyas postvittana Walker (Lepidoptera: Tortricidae).

    PubMed

    Taverner, Peter D; Bailey, Peter T; Roush, Richard T

    2002-04-01

    For the purpose of understanding better the mode of action of alkanes on insects, the relationship between mortality, weight loss in oxygen enriched atmospheres and dietary antioxidants was examined using an alkane, C15 Ampol CPD and a spray oil, C23 DC-Tron NR, on lightbrown apple moth, Epiphyas postvittana Walker, (LBAM). The results showed that the surfactant blend used in CPD was an insignificant contributor to the overall toxicity of dilute oil/water emulsions. Higher weight loss occurred in CPD-dipped larvae than C23 DC-Tron NR-dipped larvae, which suggests that alkanes disrupt tracheal waxes and render insects more prone to desiccation. High levels of oxygen increased the toxicity of CPD to LBAM larvae. In addition, dietary supplements of anti-oxidant, alpha-tocopherol, fed to LBAM larvae were successful in reducing the toxicity of CPD. These results suggest that the alkane may contribute to oxidative injury. The potential role of oil-induced oxidative stress in acute and chronic toxicity in insects is discussed. PMID:11975180

  4. Dose-Response Relationship of Physical Activity to Premature and Total All-Cause and Cardiovascular Disease Mortality in Walkers

    PubMed Central

    Williams, Paul T.

    2013-01-01

    Purpose To assess the dose-response relationships between cause-specific mortality and exercise energy expenditure in a prospective epidemiological cohort of walkers. Methods The sample consisted of the 8,436 male and 33,586 female participants of the National Walkers' Health Study. Walking energy expenditure was calculated in metabolic equivalents (METs, 1 MET?=?3.5 ml O2/kg/min), which were used to divide the cohort into four exercise categories: category 1 (?1.07 MET-hours/d), category 2 (1.07 to 1.8 MET-hours/d), category 3 (1.8 to 3.6 MET-hours/d), and category 4 (?3.6 MET-hours/d). Competing risk regression analyses were use to calculate the risk of mortality for categories 2, 3 and 4 relative to category 1. Results 22.9% of the subjects were in category 1, 16.1% in category 2, 33.3% in category 3, and 27.7% in category 4. There were 2,448 deaths during the 9.6 average years of follow-up. Total mortality was 11.2% lower in category 2 (P?=?0.04), 32.4% lower in category 3 (P<10?12) and 32.9% lower in category 4 (P?=?10?11) than in category 1. For underlying causes of death, the respective risk reductions for categories 2, 3 and 4 were 23.6% (P?=?0.008), 35.2% (P<10?5), and 34.9% (P?=?0.0001) for cardiovascular disease mortality; 27.8% (P?=?0.18), 20.6% (P?=?0.07), and 31.4% (P?=?0.009) for ischemic heart disease mortality; and 39.4% (P?=?0.18), 63.8% (P?=?0.005), and 90.6% (P?=?0.002) for diabetes mortality when compared to category 1. For all related mortality (i.e., underlying and contributing causes of death combined), the respective risk reductions for categories 2, 3 and 4 were 18.7% (P?=?0.22), 42.5% (P?=?0.001), and 57.5% (P?=?0.0001) for heart failure; 9.4% (P?=?0.56), 44.3% (P?=?0.0004), and 33.5% (P?=?0.02) for hypertensive diseases; 11.5% (P?=?0.38), 41.0% (P<10?4), and 35.5% (P?=?0.001) for dysrhythmias: and 23.2% (P?=?0.13), 45.8% (P?=?0.0002), and 41.1% (P?=?0.005) for cerebrovascular diseases when compared to category 1. Conclusions There are substantial health benefits to exceeding the current exercise guidelines. PMID:24312170

  5. A fully covariant information-theoretic ultraviolet cutoff for scalar fields in expanding Friedmann Robertson Walker spacetimes

    NASA Astrophysics Data System (ADS)

    Kempf, A.; Chatwin-Davies, A.; Martin, R. T. W.

    2013-02-01

    While a natural ultraviolet cutoff, presumably at the Planck length, is widely assumed to exist in nature, it is nontrivial to implement a minimum length scale covariantly. This is because the presence of a fixed minimum length needs to be reconciled with the ability of Lorentz transformations to contract lengths. In this paper, we implement a fully covariant Planck scale cutoff by cutting off the spectrum of the d'Alembertian. In this scenario, consistent with Lorentz contractions, wavelengths that are arbitrarily smaller than the Planck length continue to exist. However, the dynamics of modes of wavelengths that are significantly smaller than the Planck length possess a very small bandwidth. This has the effect of freezing the dynamics of such modes. While both wavelengths and bandwidths are frame dependent, Lorentz contraction and time dilation conspire to make the freezing of modes of trans-Planckian wavelengths covariant. In particular, we show that this ultraviolet cutoff can be implemented covariantly also in curved spacetimes. We focus on Friedmann Robertson Walker spacetimes and their much-discussed trans-Planckian question: The physical wavelength of each comoving mode was smaller than the Planck scale at sufficiently early times. What was the mode's dynamics then? Here, we show that in the presence of the covariant UV cutoff, the dynamical bandwidth of a comoving mode is essentially zero up until its physical wavelength starts exceeding the Planck length. In particular, we show that under general assumptions, the number of dynamical degrees of freedom of each comoving mode all the way up to some arbitrary finite time is actually finite. Our results also open the way to calculating the impact of this natural UV cutoff on inflationary predictions for the cosmic microwave background.

  6. Block modeling of crustal deformation of the northern Walker Lane and Basin and Range from GPS velocities

    NASA Astrophysics Data System (ADS)

    Hammond, William C.; Blewitt, Geoffrey; Kreemer, Corné

    2011-04-01

    We infer rates of crustal deformation in the northern Walker Lane (NWL) and western Basin and Range using data from the Mobile Array of GPS for Nevada transtension, and other continuous GPS networks including the EarthScope Plate Boundary Observatory. We present 224 new GPS velocities, correct them for the effects of viscoelastic postseismic relaxation, and use them to constrain a block model to estimate fault slip rates. The data segregate the NWL into domains based on differences in deformation rate, pattern, and style. Deformation is transtensional, with highest rates near the western and eastern edges of the NWL. Some basins, e.g., Tahoe, experience shear deformation and extension. Normal slip is distributed throughout the NWL and Basin and Range, where 11 subparallel range-bounding normal fault systems have an average horizontal extension rate of 0.1 mm/yr. Comparison between geologic and geodetic slip rates indicates that out of 12 published geologic rates, 10 agree with geodetic rates to within uncertainties. This suggests that smaller crustal blocks move steadily, similar to larger lithospheric plates, and that geodetic measurements of slip rates are reliable in zones of complex crustal deformation. For the two slip rates that disagree, geologic rates are greater. The vertical axis rotation rate of the Carson domain is -1.3 ± 0.1°/My clockwise, lower than the 3° to 6°/My obtained in paleomagnetic measurements. This suggests that vertical axis rotation rates may have decreased over the last 9-13 My as the role of faulting has increased at the expense of rigid rotations.

  7. A westward extension of the warm pool leads to a westward extension of the Walker circulation, drying eastern Africa

    NASA Astrophysics Data System (ADS)

    Williams, A. Park; Funk, Chris

    2011-12-01

    Observations and simulations link anthropogenic greenhouse and aerosol emissions with rapidly increasing Indian Ocean sea surface temperatures (SSTs). Over the past 60 years, the Indian Ocean warmed two to three times faster than the central tropical Pacific, extending the tropical warm pool to the west by ~40° longitude (>4,000 km). This propensity toward rapid warming in the Indian Ocean has been the dominant mode of interannual variability among SSTs throughout the tropical Indian and Pacific Oceans (55°E-140°W) since at least 1948, explaining more variance than anomalies associated with the El Niño-Southern Oscillation (ENSO). In the atmosphere, the primary mode of variability has been a corresponding trend toward greatly increased convection and precipitation over the tropical Indian Ocean. The temperature and rainfall increases in this region have produced a westward extension of the western, ascending branch of the atmospheric Walker circulation. Diabatic heating due to increased mid-tropospheric water vapor condensation elicits a westward atmospheric response that sends an easterly flow of dry air aloft toward eastern Africa. In recent decades (1980-2009), this response has suppressed convection over tropical eastern Africa, decreasing precipitation during the `long-rains' season of March-June. This trend toward drought contrasts with projections of increased rainfall in eastern Africa and more `El Niño-like' conditions globally by the Intergovernmental Panel on Climate Change. Increased Indian Ocean SSTs appear likely to continue to strongly modulate the Warm Pool circulation, reducing precipitation in eastern Africa, regardless of whether the projected trend in ENSO is realized. These results have important food security implications, informing agricultural development, environmental conservation, and water resource planning.

  8. Enhancement of photodynamic therapy due to hyperbaric hyperoxia: an experimental study of Walker 256 tumors in rats

    NASA Astrophysics Data System (ADS)

    Nicola, Jorge H.; Colussi, Valdir C.; Nicola, Ester M. D.; Metze, Konradin

    1997-05-01

    Photodynamic therapy (PDT), which is now an approved treatment for many types of cancers, is based on the simultaneous involvement of three factors, namely: tumor tissue retention of a specific photosensitizer; local illumination of the lesion with a visible light source and the occurrence of oxygen in the triplet state. Theoretically, a change in any one of these factors may be compensated by a change in the other two factors, leading to the same therapeutic result. In practice, this is not true, since we are dealing with living tissue, but we may expect to find an ideal combination of these three factors which may give the best clinical results. In this work we present experimental results of PDT under Hyperbaric hyperoxia (HBO) in tumor masses of the dorsal subcutaneous tissue of rats. These tumors were created by previous inoculation of 'Walker 256' neoplastic cells Hematoporphyrin Ester (HpE) was administered as the photosensitizer. The rats were pressurized at up to 3 atm with a 100 percent continuous oxygen ventilation environment in a specially designed hyperbaric chamber. The skin area above the tumor was photosensitized for 45 minutes with a 7 mw HeNe laser. Twenty four hours later, the tumor was removed for study. In all the animals treated with PDT/HBO histology revealed a very important reduction in the number of tumor cells as compared with the PDT controls in normal atmospheric condition, showing numerous apoptotic as well as necrotic cells at the border of the radiated area. The observed enhancement in the PDT for this situation is, of course, related to the extra oxygen in the circulatory system.

  9. In-stream biotic control on nutrient biogeochemistry in a forested sheadwater tream, West Fork of Walker Branch

    SciTech Connect

    Roberts, Brian J [ORNL; Mulholland, Patrick J [ORNL

    2007-01-01

    A growing body of evidence demonstrates the importance of in-stream processing in regulating nutrient export, yet the influence of temporal variability in stream metabolism on net nutrient uptake has not been explicitly addressed. Streamwater DIN and SRP concentrations in Walker Branch, a first-order deciduous forest stream in eastern Tennessee, show a repeated pattern of annual maxima in summer and biannual minima in spring and autumn. Temporal variations in catchment hydrologic flowpaths result in lower winter and higher summer nutrient concentrations, but do not explain the spring and autumn nutrient minima. Ambient nutrient uptake rates were measured 2-3 times per week over an 18-mo period and compared to daily rates of gross primary production (GPP) and ecosystem respiration (ER) to examine the influence of in-stream biotic activity on nutrient export. GPP and ER rates explained 85% of the variation in net DIN retention with high net NO3- uptake (and lower net NH4+ release) rates occurring during spring and autumn and net DIN release in summer. Diel nutrient concentration patterns were examined several times throughout the year to determine the relative importance of autotrophic and heterotrophic activity on net nutrient uptake. High spring GPP corresponded to daily decreases in NO3- over the illuminated hours resulting in high diel NO3- amplitude which dampened as the canopy closed. GPP explained 91% of the variance in diel NO3- amplitude. In contrast, the autumn nutrient minima was largely explained by heterotrophic respiration since GPP remained low and little diel NO3- variation was observed during the autumn.

  10. Lidar-Based Mapping of Late Quaternary Faulting Along the Grizzly Valley Fault, Walker Lane Seismic Belt, California

    NASA Astrophysics Data System (ADS)

    Hitchcock, C. S.; Hoirup, D. F.; Barry, G.; Pearce, J.; Glick, F.

    2012-12-01

    The Grizzly Valley fault (GVF) is located within the northern Walker Lane, a zone of right-lateral shear between the Sierra Nevada and the Basin and Range in Plumas County. The GVF extends southeasterly from near Mt. Ingalls along the eastern side of Lake Davis. It may partially connect with the Hot Creek fault within Sierra Valley and extend south to Loyalton with an overall approximate length of 50 km. Comparison of high-resolution topography developed from LiDAR data with published bedrock geologic mapping documents the presence of geomorphic features that provide information on fault activity of the GVF. Field mapping verified tectonically deformed and offset late Quaternary surfaces identified on bare-earth LiDAR imagery across the GVF within glacial deposits on the eastern margin of Lake Davis, and alluvial deposits in Sierra Valley. Along the GVF, conspicuous geomorphic and hydrologic features include scarps in alluvial surfaces, elongated depressions aligned with adjacent linear escarpments, truncated bedrock spurs, closed depressions, linear swales, right-lateral deflections of creeks and river courses, and shutter ridges, as well as springs and linear seeps consistent with right-lateral strike-slip faulting. The discontinuous nature of observed fault traces combined with the apparent down-to-the-west offset of alluvial surfaces at the southern and northern ends of the eastern margin of Lake Davis are consistent with a broad bend or step over in the fault. Scarp profiles of apparently faulted surfaces extracted from LiDAR data document vertical offsets of up to 14 m. Our study suggest that the GVF is an oblique, right-lateral fault that has been active in the late Quaternary. This study complements on-going investigations by DWR to assess the impact of seismic hazards on State Water Project infrastructure.

  11. Abscopal antitumor immune effects of magnet-mediated hyperthermia at a high therapeutic temperature on Walker-256 carcinosarcomas in rats

    PubMed Central

    WANG, HUI; ZHANG, LI; SHI, YINGRUI; JAVIDIPARSIJANI, SARA; WANG, GUIRONG; LI, XIAO; OUYANG, WEIWEI; ZHOU, JUMEI; ZHAO, LINGYUN; WANG, XIAOWEN; ZHANG, XIAODONG; GAO, FUPING; LIU, JINGSHI; LUO, JUNMING; TANG, JINTIAN

    2014-01-01

    The abscopal effect has previously been described in various tumors and is associated with radiation therapy and hyperthermia, with possible underlying mechanisms explaining each observed case. In the present study, we aimed to investigate the antitumor effects of magnet-mediated hyperthermia on Walker-256 carcinosarcomas in rats at two different temperature ranges (42–46°C and 50–55°C). We also aimed to identify whether a higher therapeutic temperature of magnetic-mediated hyperthermia improves the abscopal antitumor effects, where localised irradiation of the tumor causes not only the irradiated tumor to shrink, but also tumors located far from the area of irradiation. Following induction of carcinosarcoma in both sides of the body, magnet-mediated hyperthermia was applied to one side only, leaving the other side as a control. The changes in tumor growth were observed. Our results demonstrated that magnet-mediated hyperthermia at a higher temperature inhibited the growth of carcinosarcoma at the site of treatment. Furthermore, the growth of the carcinosarcoma on the untreated side was also inhibited. The expression levels of proliferating cell nuclear antigen were decreased in the hyperthermia group, which was more significant in the higher temperature test group. Flow cytometric analysis showed an increased number of CD4- and CD8-positive T cells, and enzyme-linked immunosorbent assay showed increased levels of interferon-? and interleukin-2 in the higher temperature group. These results suggested that magnet-mediated hyperthermia at a higher temperature (50–55°C) can improve the abscopal antitumor effects and stimulate a greater endogenous immune response in carcinosarcoma-bearing rats. PMID:24527084

  12. Recent crustal movements in the Sierra Nevada-Walker lane region of California-Nevada: Part i, rate and style of deformation

    USGS Publications Warehouse

    Slemmons, D.B.; Wormer, D.V.; Bell, E.J.; Silberman, M.L.

    1979-01-01

    This review of geological, seismological, geochronological and paleobotanical data is made to compare historic and geologic rates and styles of deformation of the Sierra Nevada and western Basin and Range Provinces. The main uplift of this region began about 17 m.y. ago, with slow uplift of the central Sierra Nevada summit region at rates estimated at about 0.012 mm/yr and of western Basin and Range Province at about 0.01 mm/yr. Many Mesozoic faults of the Foothills fault system were reactivated with normal slip in mid-Tertiary time and have continued to be active with slow slip rates. Sparse data indicate acceleration of rates of uplift and faulting during the Late Cenozoic. The Basin and Range faulting appears to have extended westward during this period with a reduction in width of the Sierra Nevada. The eastern boundary zone of the Sierra Nevada has an irregular en-echelon pattern of normal and right-oblique faults. The area between the Sierra Nevada and the Walker Lane is a complex zone of irregular patterns of ho??rst and graben blocks and conjugate normal-to right- and left-slip faults of NW and NE trend, respectively. The Walker Lane has at least five main strands near Walker Lake, with total right-slip separation estimated at 48 km. The NE-trending left-slip faults are much shorter than the Walker Lane fault zone and have maximum separations of no more than a few kilometers. Examples include the 1948 and 1966 fault zone northeast of Truckee, California, the Olinghouse fault (Part III) and possibly the almost 200-km-long Carson Lineament. Historic geologic evidence of faulting, seismologic evidence for focal mechanisms, geodetic measurements and strain measurements confirm continued regional uplift and tilting of the Sierra Nevada, with minor internal local faulting and deformation, smaller uplift of the western Basin and Range Province, conjugate focal mechanisms for faults of diverse orientations and types, and a NS to NE-SW compression axis (??1) and an EW to NW-SE extension axis (??3). ?? 1979.

  13. The Relationship of Walking Intensity to Total and Cause-Specific Mortality. Results from the National Walkers’ Health Study

    PubMed Central

    Williams, Paul T.; Thompson, Paul D.

    2013-01-01

    Purpose Test whether: 1) walking intensity predicts mortality when adjusted for walking energy expenditure, and 2) slow walking pace (?24-minute mile) identifies subjects at substantially elevated risk for mortality. Methods Hazard ratios from Cox proportional survival analyses of all-cause and cause-specific mortality vs. usual walking pace (min/mile) in 7,374 male and 31,607 female recreational walkers. Survival times were left censored for age at entry into the study. Other causes of death were treated as a competing risk for the analyses of cause-specific mortality. All analyses were adjusted for sex, education, baseline smoking, prior heart attack, aspirin use, diet, BMI, and walking energy expenditure. Deaths within one year of baseline were excluded. Results The National Death Index identified 1968 deaths during the average 9.4-year mortality surveillance. Each additional minute per mile in walking pace was associated with an increased risk of mortality due to all causes (1.8% increase, P=10-5), cardiovascular diseases (2.4% increase, P=0.001, 637 deaths), ischemic heart disease (2.8% increase, P=0.003, 336 deaths), heart failure (6.5% increase, P=0.001, 36 deaths), hypertensive heart disease (6.2% increase, P=0.01, 31 deaths), diabetes (6.3% increase, P=0.004, 32 deaths), and dementia (6.6% increase, P=0.0004, 44 deaths). Those reporting a pace slower than a 24-minute mile were at increased risk for mortality due to all-causes (44.3% increased risk, P=0.0001), cardiovascular diseases (43.9% increased risk, P=0.03), and dementia (5.0-fold increased risk, P=0.0002) even though they satisfied the current exercise recommendations by walking ?7.5 metabolic equivalent (MET)-hours per week. Conclusions The risk for mortality: 1) decreases in association with walking intensity, and 2) increases substantially in association for walking pace ?24 minute mile (equivalent to <400m during a six-minute walk test) even among subjects who exercise regularly. PMID:24260542

  14. Long-Term Data Reveal Patterns and Controls on Stream Water Chemistry in a Forested Stream: Walker Branch, Tennessee

    SciTech Connect

    Lutz, Brian D [Duke University; Mulholland, Patrick J [ORNL; Bernhardt, Emily [Duke University

    2012-01-01

    We present 20 years of weekly stream water chemistry, hydrology, and climate data for the Walker Branch watershed in eastern Tennessee, USA. Since 1989, the watershed has experienced a similar to 1.08 degrees C increase in mean annual temperature, a similar to 20% decline in precipitation, and a similar to 30% increase in forest evapotranspiration rates. As a result, stream runoff has declined by similar to 34%. We evaluate long-term trends in stream water concentrations and fluxes for nine solutes and use wet deposition data to calculate approximate watershed input-output budgets. Dissolved constituents were classified as geochemical solutes (Ca2+, Mg2+, and SO42-) or nutrients (NH4+, NO3-, soluble reactive phosphorus [SRP], total soluble nitrogen [TSN], total soluble phosphorus [TSP], and dissolved organic carbon [DOC]). Geochemical solutes are predominantly controlled by discharge, and the long-term changes in catchment hydrology have led to significant trends in the concentrations and fluxes of these solutes. Further, the trends in geochemical solute concentrations indicate shifting soil flowpath contributions to streamflow generation through time, with deep groundwater having a greater proportional contribution in recent years. Despite dramatic changes in watershed runoff, there were no trends in inorganic nutrient concentrations (NH4+, NO3-, and SRP). While most nutrients entering the watershed are retained, stream fluxes of nutrient solutes have declined significantly as a result of decreasing runoff. Nutrient concentrations in the stream exhibit large seasonality controlled by in-stream biological uptake. Stream benthic communities are sensitive to hydrologic disturbance, and changes in the frequency or intensity of storm events through time can affect nutrient fluxes. Stream NO3- concentrations are also sensitive to drought, with concentrations decreasing (increasing) if conditions during the three years prior to the time of sampling were drier (wetter) than the long-term mean. Future changes in the incidence of storm events, as well as the number and duration of droughts, have the potential to significantly alter watershed nutrient losses. Our analysis indicates that changing climates can differentially affect watershed element cycles either through changes in biogeochemical process rates or through changes in catchment hydrology. Furthermore, climate change can include both long-term trending in mean climate variables, as well as changes in the frequency and intensity of storms and droughts, with each of these types of change having distinct effects on the biological and geochemical processes governing different solutes.

  15. Constraints from GPS on Block Kinematics of the Transition between the Southern Walker Lane and the Basin and Range Province

    NASA Astrophysics Data System (ADS)

    Jha, S.; Hammond, W. C.; Kreemer, C.; Blewitt, G.

    2008-12-01

    The southern Walker Lane (SWL) is a part of the Eastern California Shear Zone that lies north of the Mojave region, bounded by the Garlock Fault to the south, the Sierra Nevada to the west, the Basin and Range to the east and by Mono Lake to the north. The region includes many northwest striking right-lateral strike slip and sub-parallel normal faults (e.g. Death Valley/Furnace Creek, Fish Lake Valley, Owens Valley), which together accommodate ~25% of the Pacific/North American relative motion. For many of these faults, and the system as a whole, there appears to be a discrepancy between geodetically and geologically inferred fault slip rates. Since the installation of the EarthScope Plate Boundary Observatory (PBO), and the Nevada Earthquake Response Network (NEARNET) of the University of Nevada, Reno, many recently obtained high- precision GPS data are now available to place improved constraints on the pattern and rates of crustal deformation of this region. In this study we use a block modeling methodology to estimate block motions and fault slip rates from GPS velocities of PBO, NEARNET and BARGEN continuous sites. Time series were obtained from raw RINEX data that we processed using the GIPSY-OASIS II software from the Jet Propulsion Laboratory together with the Ambizap software for ambiguity resolution. We have additionally included earlier published campaign-style velocities, in those areas where we do not have better coverage from other continuous/semi-continuous networks. Geologic slip rates have been obtained from the published literature. We solve for the motion of blocks using the GPS velocities that have been adjusted based on the viscoelastic modeling to estimate long term motion. To evaluate the consistency between the geologic and geodetic data, we compare long-term fault slip to slip rates inferred from geodetic results obtained over <10 years. We account for transient earthquake cycle effects by modeling the viscoelastic postseismic relaxation following major historic earthquakes in the region. In particular we model the 1999 Hector Mine, 1992 Landers, 1952 Kern County, and 1872 Owens Valley earthquakes. GPS velocities adjusted for transient effects indicate that there is a distinct NW trend in the motions of the blocks with rates decreasing to the east. However, deformation rates are greater than zero east of the SWL in the Basin and Range. The preliminary results obtained from the block model indicate significant slip at the easternmost edge of the model, in the vicinity of Yucca Mountain and the Stateline fault.

  16. Integrated Kinematic Analysis of GPS and Fault Slip Data in the Eastern California Shear Zone, Walker Lane and Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Hammond, W. C.; Thatcher, W.

    2001-12-01

    The Sierra Nevada (SN) microplate moves roughly N50?W with respect to North America (NA), around an Euler pole that lies in the Pacific (PA) basin to the west and south. Its motion is indicative of processes governing the deformation of the Walker Lane and Eastern California Shear Zone, accommodating east to west expansion of the Basin and Range and approximately 25% of PA/NA dextral shear. To date, estimates for the location of the SN/NA pole obtained by GPS, VLBI and geologic data differ by at least 30 degrees [e.g. Argus and Gordon, 1996; Hearn and Humphreys, 1998]. The difference between these poles may, in part, be attributable to the type of data used in the analyses. The GPS determined velocity field potentially contains artifacts of the earthquake cycle such as recoverable elastic deformation preceded by slip at depth, fault creep, and viscoelastic relaxation following earthquakes on block bounding faults. We use Global Positioning System (GPS), fault strike and slip rate data to constrain the kinematics of the eastern boundary of the Sierra Nevada (SN) microplate, and western Basin and Range province of western North America. Data include previously published GPS measurements [Bennet et al., 1998; Thatcher et al., 1999; Gan et al., 2000; Svarc et al., submitted manuscript 2001], recently collected GPS data, and recently compiled fault maps of Nevada and California that include fault strike, slip sense and slip rate estimates. GPS velocities are refined with the Quasi Observation Combination Analysis algorithm of Dong et al. From these data we constrain the spatial variation in the rate and style of deformation throughout the region, and identify components of the deformation that are relevant to interaction of the PA/NA transform margin and Basin and Range extension. Using two-dimensional viscoelastic finite elements we derive kinematic models representative of the instantaneous (GPS) time scale, in preparation for future modeling of the longer term (Quaternary and Holocene) time scale. We determine the continuous elastic deformation field that is most consistent with the GPS data, kinematic consistency within the modeled domain, and boundary conditions imposed by PA/NA motion.

  17. Clustering of velocities in a GPS network spanning the Sierra Nevada Block, the northern Walker Lane Belt, and the Central Nevada Seismic Belt, California-Nevada

    USGS Publications Warehouse

    Savage, James C.; Simpson, Robert W.

    2013-01-01

    The deformation across the Sierra Nevada Block, the Walker Lane Belt, and the Central Nevada Seismic Belt (CNSB) between 38.5°N and 40.5°N has been analyzed by clustering GPS velocities to identify coherent blocks. Cluster analysis determines the number of clusters required and assigns the GPS stations to the proper clusters. The clusters are shown on a fault map by symbols located at the positions of the GPS stations, each symbol representing the cluster to which the velocity of that GPS station belongs. Fault systems that separate the clusters are readily identified on such a map. Four significant clusters are identified. Those clusters are strips separated by (from west to east) the Mohawk Valley-Genoa fault system, the Pyramid Lake-Wassuk fault system, and the Central Nevada Seismic Belt. The strain rates within the westernmost three clusters approximate simple right-lateral shear (~13 nstrain/a) across vertical planes roughly parallel to the cluster boundaries. Clustering does not recognize the longitudinal segmentation of the Walker Lane Belt into domains dominated by either northwesterly trending, right-lateral faults or northeasterly trending, left-lateral faults.

  18. Effect of fish oil supplementation for 2 generations on changes in macrophage function induced by Walker 256 cancer cachexia in rats.

    PubMed

    Folador, Alessandra; Hirabara, Sandro M; Bonatto, Sandro J R; Aikawa, Júlia; Yamazaki, Ricardo K; Curi, Rui; Fernandes, Luiz C

    2007-01-15

    The effect of coconut fat (rich in medium saturated fatty acids) or fish oil (rich in omega-3 polyunsaturated fatty acids) supplementation for 2 generations on tumor growth, cancer cachexia, animal survival and macrophage function was investigated in Walker 256 tumor-bearing rats. Female Wistar rats were supplemented with coconut fat or fish oil prior to mating and then throughout pregnancy and gestation. Both supplementations were daily and orally given at 1 g per kg body weight as a single bolus. Same treatment was performed by the 2 following generations. At 90 days of age, male offspring (50%) from F2 generation were subcutaneously inoculated with 2 x 10(7) Walker 256 tumor cells. At 14 days after tumor implantation, rats not supplemented displayed cancer cachexia characterized by loss of body weight, hypoglycemia, hyperlacticidemia, hypertriglyceridemia, decreased food intake and depletion of glycogen stores in the liver and skeletal muscles. Supplementation with coconut fat did not affect these parameters. However, supplementation with fish oil decreased tumor growth (59%), prevented body weight loss and food intake reduction and attenuated cancer cachexia. In addition, fish oil increased animal survival up to 20 days (from 25% in rats not supplemented to 67% in rats supplemented with fish oil) and improved macrophage function characterized by increased phagocytosis capacity and production of hydrogen peroxide and nitric oxide. These results suggest that fish oil supplementation for 2 generations improves macrophage function in association to reduced tumor growth and attenuated cancer cachexia, maintaining food intake and increasing animal survival. PMID:17066422

  19. PoreWalker: A Novel Tool for the Identification and Characterization of Channels in Transmembrane Proteins from Their Three-Dimensional Structure

    PubMed Central

    Thornton, Janet M.

    2009-01-01

    Transmembrane channel proteins play pivotal roles in maintaining the homeostasis and responsiveness of cells and the cross-membrane electrochemical gradient by mediating the transport of ions and molecules through biological membranes. Therefore, computational methods which, given a set of 3D coordinates, can automatically identify and describe channels in transmembrane proteins are key tools to provide insights into how they function. Herein we present PoreWalker, a fully automated method, which detects and fully characterises channels in transmembrane proteins from their 3D structures. A stepwise procedure is followed in which the pore centre and pore axis are first identified and optimised using geometric criteria, and then the biggest and longest cavity through the channel is detected. Finally, pore features, including diameter profiles, pore-lining residues, size, shape and regularity of the pore are calculated, providing a quantitative and visual characterization of the channel. To illustrate the use of this tool, the method was applied to several structures of transmembrane channel proteins and was able to identify shape/size/residue features representative of specific channel families. The software is available as a web-based resource at http://www.ebi.ac.uk/thornton-srv/software/PoreWalker/. PMID:19609355

  20. Howie Choset Sean Walker

    E-print Network

    LaValle, Steven M.

    , Pennsylvania 15213 USA choset@cs.cmu.edu Joel Burdick California Institute of Technology Mail Code 104 (HGVG) which is described in Choset and Burdick The International Journal of Robotics Research Vol. 19

  1. MAGNETORECEPTION MICHAEL M. WALKER

    E-print Network

    in the elasmobranch and teleost fishesduring the 1960s (Murr ay, 1960;Dijk graaf and Kalm ijn, 1962;Kalmij n, 1966;von of the elasmobranch fishes(Clusin and Bennett, 1979a,b) and in the tuberous electroreceptors of some freshwater a decadeafter the electrical sense of elasmobranch fishes had been demonstrated at the behavioral

  2. 1 Mark E. Walker

    E-print Network

    Walker, Mark

    Geometry", (I was * *one of six faculty on this grant), June 1997 - May 2000; $30,030. 3.NSA faculty on this grant), July 2000 - June 2004; $45,936. 5.NSA Grant, "Semi-topological K for this grant, not I. 7.NSA Grant, "K-theory, Lawson Homology, and Hodge Theory", January 2005 - D

  3. "Frog" Walker & Jim Calvert 

    E-print Network

    Unknown

    2011-08-17

    The purpose of this study was to assess learning in sixth grade students? by gain scores in science and mathematics while participating in the integrative curriculum modules developed by the Partnership for Environmental ...

  4. Geodetic vs. Geologic Measures of Fault Slip Rates in the Northern Walker Lane, Basin and Range Province, Western United States

    NASA Astrophysics Data System (ADS)

    Hammond, W. C.; Kreemer, C.; Blewitt, G.

    2008-05-01

    Quantifying faults slip rates and styles is an important objective in the study of crustal deformation. Fault slip rates are used to quantify seismic hazard associated with active faults, and are an important input into the U.S.G.S. seismic hazard maps. However, when multiple types of data (e.g. geologic, seismic and geodetic) are used to measure slip rates, results from the different techniques can be corroborative, complementary, or in direct conflict. Geologic methods provide some of the only constraints on slip rates of individual faults over hundreds to tens of thousands of years, time scales that are significant with respect to observed deformation patterns, and likely representative of modern hazard. On the other hand geodetic measurements provide strong constraints on the medium to long spatial wavelength (>50 km) budgets of deformation, and on geographic changes in deformation style, and have the potential to provide geographically complete measurements of surface deformation. However, geodetic measurements can be influenced by earthquake cycle effects, e.g. owing to interseismic fault locking and postseismic relaxation, which limit their ability to resolve individual slip rates, especially in complex systems with many closely spaced faults. The northern Walker Lane (NWL), in the western Basin and Range Province (BRP) of the United States, is an example of a complex system of dextral, normal and sinestral faults that work together to accommodate approximately 10 mm/yr of relative motion between the Sierra Nevada/Great Valley block and the central part of the BRP. To exploit the strengths of each dataset, we have built a detailed model of NWL crustal blocks and are using geodetic and geologic data to resolve patterns of crustal deformation. We use a block modeling technique that incorporates the strengths of both targeted geologic investigations of slip rates on individual faults and longer wavelength constraints offered by GPS geodesy. To constrain these models we use a compilation of GPS data from our own 163-site MAGNET GPS network plus regional continuous GPS sites from the Plate Boundary Observatory and BARGEN networks, and published USGS campaign velocities. For geologic data we have tabulated slip rate estimates into two categories, 1) published studies with quantitative rates valid in the Quaternary, and 2) the USGS Quaternary Fault and Fold Database that is a comprehensive web-available database with many reconnaissance level estimates of fault slip rate. Our modeling helps unravel the slip rate debate by distinguishing between system-wide discrepancies in integrated moment rate across the NWL, and point-wise discrepancies in individual fault slip rates. Our modeling shows that on the systemic level, even a single reliable geologic slip rate can improve the condition of the modeling, and on the individual fault level geodetic constraints can eliminate feasibility of some very high slip rates allowed by the geologic data. We conclude that for the NWL, the rate disagreement is attributable to an incomplete catalog of geologic slip rates and not to systematic underestimation of slip rates in the individual studies.

  5. Exploring Western and Eastern Pacific contributions to the 21st century Walker circulation intensification and teleconnected precipitation declines (Invited)

    NASA Astrophysics Data System (ADS)

    Funk, C. C.; Hoerling, M. P.; Hoell, A.; Verdin, J. P.; Robertson, F. R.; Alured, D.; Liebmann, B.

    2013-12-01

    As the earth's population, industry, and agricultural systems continue to expand and increase demand for limited hydrologic resources, developing better tools for monitoring, analyzing and perhaps even predicting decadal variations in precipitation will enable the climate community to better inform important policy and management decisions. To this end, in support of the development and humanitarian relief efforts of the US Agency for International Development, USGS, NOAA, UC Santa Barbara, and NASA scientists have been exploring global precipitation trends using observations and new ensembles of atmospheric general circulation model (AGCM) simulations from the ECHAM5, GFSv2, CAM4 and GMAO models. This talk summarizes this work, and discusses how combined analyses of AGCM simulations and observations might lead to credible decadal projections, for some regions and seasons, based on the strength of the Indo-Pacific warming signal. Focusing on the late boreal spring, a critical period for food insecure Africa, we begin by linearly decomposing 1900-2012 sea surface temperatures (SST) into components loading strongly in the Indo-Western Pacific and Eastern Pacific. Eastern Pacific (EP) SST variations are based on regressions with three time series: the first and second principal components of equatorial Pacific SST and the Pacific Decadal Oscillation. These influences are removed from Indo-Pacific SSTs, and the Indo-Western Pacific (IWP) SST variations are defined by the 1st principal component of the residuals, which we refer to as the Indo-West Pacific Warming Signal (IWPWS). The pattern of IWPWS SST changes resembles recent assessments of centennial warming, and identifies rapid warming in the equatorial western Pacific and north and south Pacific convergence zones. The circulation impacts of IWP and EP SST forcing are explored in two ways. First, assuming linear SST forcing relationships, IWP and EP decompositions of ECHAM5, GFS, CAM4 and GMAO AGCM simulations are presented. These results suggest that a substantial component of the recent Walker circulation intensification has been related to the IWPWS. The IWPWS warming extends from just north of Papua New Guinea to just west of Hawaii, and appears associated with SLP, wind and rainfall responses consistent with enhanced Indo-Pacific convection. These decomposition results are compared with a set of numerical simulation experiments based on the ECHAM5 and GFS models forced with characteristic IWP and EP SST for 1983-1996 and 1999-2012. The talk concludes with a tentative discussion of the decadal predictability associated with the IWPWS. Using both observed and model-simulated precipitation, we briefly explore potential IWPWS drought teleconnection regions in the Americas, Asia, Middle East, and Eastern Africa. Figure 1. Western Pacific and Eastern Pacific SST changes between 1999-2012 and 1983-1996. Figure 2. Western Pacific and Eastern Pacific GPCP precipitation changes between 1999-2012 and 1983-1996.

  6. Assessment of forearm and plantar foot load in the elderly using a four-wheeled walker with armrest and the effect of armrest height

    PubMed Central

    Ko, Chang-Yong; Kim, Sol-Bi; Choi, Hyuk-Jae; Chang, Yunhee; Kang, Sungjae; Heo, Yoon; Ryu, Jeicheong; Kim, Gyoosuk; Mun, Museong

    2014-01-01

    Background Patients with hand and/or wrist pathology are recommended to have a four-wheeled walker with an arm rest (FWW-AR) rather than a standard walker or a standard four-wheeled walker (FWW). However, only a few quantitative studies have been performed to compare upper and lower extremity weight bearing. The aim of this study was to evaluate forearm and foot weight bearing using a FWW-AR and the effect of the armrest height. Methods Eleven elderly women (mean age 80.1±5.3 years; mean height 148.5±4.0 cm; mean weight 51.2±9.0 kg) were enrolled. The subjects walked with an FWW-AR, with the elbow in either 90 degree (D90) or 130 degree (D130) flexion, for a distance of 10 m. Surface electromyographic signals were recorded for the upper, middle, and lower trapezius, anterior deltoid, and erector spinae muscles; walking velocity was measured with the subjects weight bearing on their feet and forearms while walking. Simultaneously, the maximum plantar and forearm loads during walking with an FWW-AR were measured. Results The normalized foot plantar loads were lower at D90 than at D130, while the normalized forearm load was higher at D90 than at D130 (all P<0.05; left foot, 7.9±0.1 N/kg versus 8.8±0.1 N/kg; right foot, 8.6±0.2 N/kg versus. 9.6±0.1 N/kg; left forearm, 1.8±0.5 N/kg versus 0.8±0.2 N/kg; and right forearm, 2.0±0.5 N/kg versus 1.0±0.2 N/kg, respectively). The surface electromyographic activity of the muscles involved in shoulder elevation and the walking velocity were both lower with the elbow at D90 than at D130 (all P<0.05; left upper trapezius, 98.7%±19.5% versus 132.6%±16.9%; right upper trapezius, 83.4%±10.6% versus 108.1%±10.5%; left anterior deltoid, 94.1%±12.8% versus 158.6%±40.4%; right anterior deltoid, 99.1%±15.0% versus 151.9%±19.4%; and velocity, 0.6±0.1 m/sec versus 0.7±0.1 m/sec, respectively). Conclusion Weight bearing on the lower extremities is significantly reduced when the upper extremities are supported during walking with an FWW-AR. Furthermore, the weight bearing profile is dependent on the armrest height. PMID:25342894

  7. Chai, S.S., Veenendaal,B., West G. and J.P. Walker (2009). Input Parameter Selection for Soil Moisture Retrieval Using an Artificial Neural Network. In: Ostendorf, B., Baldock, P., Bruce, D., Burdett, M. and P. Corcoran (eds.),

    E-print Network

    Walker, Jeff

    2009-01-01

    and run-off, the partition of available energy into latent and sensible heat, the drainage of water.walker@unimelb.edu.au ABSTRACT Factors other than soil moisture which influence the intensity of microwave emission from the soil moisture retrieval problems using passive microwave. The paper shows that, depending on the problem

  8. [16] J. J. Dongarra, R. van de Geijn, and D. W. Walker. A look at Scalable Linear Algebra Libraries. In Proceedings of the 1992 Scalable High Performance Computing Conference,

    E-print Network

    Walker, David W.

    ­ 31 ­ [16] J. J. Dongarra, R. van de Geijn, and D. W. Walker. A look at Scalable Linear Algebra Press, 1992. [17] J. J. Dongarra and R. A. van de Geijn. Two Dimensional Basic Linear Algebra Communi Conference, pages 311--316. IEEE Press, 1990. [20] R. D. Falgout, A. Skjellum, S. G. Smith, and C. H. Still

  9. Process evaluation of the project P.A.T.H.S. (secondary 2 program): findings based on the co-walker scheme.

    PubMed

    Shek, Daniel T L; Tam, Suet-yan

    2009-01-01

    To understand the implementation quality of the Tier 1 Program (Secondary 2 Curriculum) of the P.A.T.H.S. Project, process evaluation was carried out by co-walkers through classroom observation of 195 units in 131 schools. Results showed that the overall level of program adherence was generally high with an average of 84.55%, and different factors of the implementation process were evaluated as positive. Quality of program implementation and achievement of program objectives were predicted by students' participation and involvement, strategies to enhance students' motivation, opportunity for reflection, time management, and class preparation. Success in program implementation was predicted by students' participation and involvement, classroom control, interactive delivery method, strategies to enhance students' motivation, opportunity for reflection, and lesson preparation. PMID:20432602

  10. An Automated Three-Dimensional Detection and Segmentation Method for Touching Cells by Integrating Concave Points Clustering and Random Walker Algorithm

    PubMed Central

    Gong, Hui; Chen, Shangbin; Zhang, Bin; Ding, Wenxiang; Luo, Qingming; Li, Anan

    2014-01-01

    Characterizing cytoarchitecture is crucial for understanding brain functions and neural diseases. In neuroanatomy, it is an important task to accurately extract cell populations' centroids and contours. Recent advances have permitted imaging at single cell resolution for an entire mouse brain using the Nissl staining method. However, it is difficult to precisely segment numerous cells, especially those cells touching each other. As presented herein, we have developed an automated three-dimensional detection and segmentation method applied to the Nissl staining data, with the following two key steps: 1) concave points clustering to determine the seed points of touching cells; and 2) random walker segmentation to obtain cell contours. Also, we have evaluated the performance of our proposed method with several mouse brain datasets, which were captured with the micro-optical sectioning tomography imaging system, and the datasets include closely touching cells. Comparing with traditional detection and segmentation methods, our approach shows promising detection accuracy and high robustness. PMID:25111442

  11. Potential indicator species of climate changes occurring in Québec, Part 1: the small brown lacewing fly Micromus posticus (Walker) (Neuroptera: Hemerobiidae)

    PubMed Central

    2013-01-01

    Abstract Micromus posticus (Walker) is a small brown lacewing fly rarely collected in Canada and represented in collections by only a limited number of specimens. Indeed, fewer than 50 specimens were captured in Québec and Ontario over the last century, all within a small area delimited by the northern shore of Lake Erie, Ottawa and Montréal. Aylmer, located on the north shore of the Ottawa River, northwest of Ottawa, is a new, most southwestern locality record of this species for Québec. The Aylmer specimens were collected 1-7 days later than any of the known specimens collected elsewhere in Québec or in Ontario, and 16-22 days later than in the neighbouring localities, indicating an apparent phenological shift. PMID:24723766

  12. The effects of the broad-specificity lipase inhibitor, tetrahydrolipstatin, on the growth, development and survival of the larvae of Epiphyas postvittana (Walker) (Tortricidae, Lepidoptera).

    PubMed

    Markwick, Ngaire P; Poulton, Joanne; McGhie, Tony K; Wohlers, Mark W; Christeller, John T

    2011-12-01

    The effects of the lipase inhibitor, tetrahydrolipstatin (THL), on neonate Epiphyas postvittana (Walker) (Lepidoptera, Tortricidae) larvae were investigated by feeding on control artificial diets (with and without 2% ethanol) and diets containing 2% ethanol and one of three concentrations of THL (0.011%, 0.037% and 0.11%). Small but significant reductions in growth rate, percent pupation and time to pupation were observed for larvae feeding on 2% ethanol control diet compared with standard control diet, but larger reductions in all parameters occurred with increasing THL concentration. Third instar larvae fed 0.011% THL in the diet had 40% of the midgut lipase activity in the relevant control larvae and showed up-regulation of gene expression of the gastric lipase-like family but not the pancreatic lipase-like family of midgut lipases. PMID:21910995

  13. Bax/Bcl-2 protein expression ratio and leukocyte function are related to reduction of Walker-256 tumor growth after ?-hydroxy-?-methylbutyrate (HMB) administration in Wistar rats.

    PubMed

    Kuczera, Diogo; Paro de Oliveira, Heloísa Helena; Fonseca Guimarães, Fernando de Souza; de Lima, Carina; Alves, Luciana; Machado, Andressa Franzói; Coelho, Isabela; Yamaguchi, Adriana; Donatti, Lucélia; Naliwaiko, Katya; Fernandes, Luiz Claudio; Nunes, Everson Araújo

    2012-01-01

    This study investigated the mechanisms by which ?-hydroxy-?-methylbutyrate (HMB) administration in rats reduces Walker-256 tumor growth. Male Wistar rats were supplemented with HMB (76 mg/kg/day) (HW), or a placebo (W), during 8 wk by gavage. At the 6th wk, rats were inoculated with a suspension of Walker 256 tumor cells (3 × 10(7)/mL). Fifteen days after inoculation, the HW group showed higher glycemia (109.4 ± 5.53 vs. 89.87 ± 7.02 mg/dL, P < 0.05) and lower spleen (1.35 ± 0.05 vs. 1.65 ± 0.12 g, P < 0.05) and tumor weights (9.64 ± 1.07 vs. 13.55 ± 1.19 g, P < 0.05) compared to the W group. Tumor cells extracted from the HMB-treated rats displayed a 36.9% decrement in rates of proliferation ex vivo and a significant increase in the Bax/Bcl-2 protein expression ratio in comparison to those extracted from the placebo-treated rats (P < 0.05). Both phagocytic capacity and H(2)O(2) production rates were higher in polymorphnuclear cells that were obtained from the blood of the HW rats in comparison to those from the W rats (P < 0.05). Reduction of necrotic regions and an intense infiltration of leukocytes and activated granulocytes in HW were evident by transmission electron microscopy. Our findings suggest that HMB supplementation decreases tumor burden by modifying the inner environment of tumor cells and by interfering with blood leukocyte function. PMID:22242972

  14. Investigation of the Origins of Modern Firmgrounds in Walker Lake, Nevada: Implications for Lacustrine Climate Records and Hardgrounds in the Rock Record

    NASA Astrophysics Data System (ADS)

    Beckerman, L. G.; Lau, K. V.; Stewart, L. C.; Loyd, S. J.; Ibarra, Y.; Corsetti, F. A.; Stevenson, B. S.; Stamps, B. W.; Spear, J. R.

    2014-12-01

    Walker Lake, Nevada, contains locally abundant Pleistocene and Holocene carbonate structures, including tufas, stromatolites, and lithified carbonate hardgrounds. Hardgrounds are classically interpreted as forming via geobiological processes in shallow sediments. To better understand the origins of ancient hardgrounds, we investigated modern firmgrounds which we hypothesized to be incipient hardgrounds. The studied firmgrounds were brown, 1-2 cm thick with a mm-scale white or brown crust, cohesive enough to retain sharp erosional features, and were located on the western shoreline where alluvial fans enter the lake. We analyzed the elemental composition of the lakewater and porewaters in order to model mineral saturation states under lake conditions. In addition, we analyzed 16S rRNA gene diversity of the firmgrounds, porewater of adjacent sediments, and lakewater to investigate potential biological involvement. This, combined with SEM imaging, XRD analyses, and EDS analyses indicate that the firmgrounds are likely dominated by clays and granitic minerals rather than carbonate like the ancient hardgrounds. We suggest that Walker Lake firmgrounds are formed by weathering of unstable granitic minerals with no clear biological influence, likely resulting from physio-chemical processes related to groundwater-lake water mixing. Such firmgrounds may undergo subsequent replacement by calcium carbonate to form hardgrounds, resulting in carbonates with ?13C and ?18O compositions that do not reflect the lake water in which they formed. Given the apparent influence of groundwater on their formation, our work suggests that caution should be used when interpreting lacustrine hardground isotopic records as indicators of lakewater chemistry and climate.

  15. Numerical simulations of depressurization-induced gas production from gas hydrate reservoirs at the Walker Ridge 312 site, northern Gulf of Mexico

    SciTech Connect

    Myshakin, Evgeniy M.; Gaddipati, Manohar; Rose, Kelly; Anderson, Brian J.

    2012-06-01

    In 2009, the Gulf of Mexico (GOM) Gas Hydrates Joint-Industry-Project (JIP) Leg II drilling program confirmed that gas hydrate occurs at high saturations within reservoir-quality sands in the GOM. A comprehensive logging-while-drilling dataset was collected from seven wells at three sites, including two wells at the Walker Ridge 313 site. By constraining the saturations and thicknesses of hydrate-bearing sands using logging-while-drilling data, two-dimensional (2D), cylindrical, r-z and three-dimensional (3D) reservoir models were simulated. The gas hydrate occurrences inferred from seismic analysis are used to delineate the areal extent of the 3D reservoir models. Numerical simulations of gas production from the Walker Ridge reservoirs were conducted using the depressurization method at a constant bottomhole pressure. Results of these simulations indicate that these hydrate deposits are readily produced, owing to high intrinsic reservoir-quality and their proximity to the base of hydrate stability. The elevated in situ reservoir temperatures contribute to high (5–40 MMscf/day) predicted production rates. The production rates obtained from the 2D and 3D models are in close agreement. To evaluate the effect of spatial dimensions, the 2D reservoir domains were simulated at two outer radii. The results showed increased potential for formation of secondary hydrate and appearance of lag time for production rates as reservoir size increases. Similar phenomena were observed in the 3D reservoir models. The results also suggest that interbedded gas hydrate accumulations might be preferable targets for gas production in comparison with massive deposits. Hydrate in such accumulations can be readily dissociated due to heat supply from surrounding hydrate-free zones. Special cases were considered to evaluate the effect of overburden and underburden permeability on production. The obtained data show that production can be significantly degraded in comparison with a case using impermeable boundaries. The main reason for the reduced productivity is water influx from the surrounding strata; a secondary cause is gas escape into the overburden. The results dictate that in order to reliably estimate production potential, permeability of the surroundings has to be included in a model.

  16. Different phenotypes of Walker-like A box mutants of ParA homolog IncC of broad-host-range IncP plasmids.

    PubMed

    Siddique, Azeem; Figurski, David H

    2012-09-01

    The promiscuous IncP? plasmids RK2 and R995 encode a broad-host-range partition system, whose essential components include the incC and korB genes and a DNA site (O(B)) to which the korB product binds. IncC2, the smaller of the two incC products, is sufficient for stabilization of R995?incC. It is a member of the type Ia ParA family of partition ATPases. To better understand the role of ATP in partition, we constructed three alanine-substitution mutants of IncC2. Each mutation changed a different residue of the Walker-like ATP-binding and hydrolysis motif, including a lysine (K10) conserved solely among members of the ParA and MinD families. All three IncC2 mutants were defective in plasmid partition, but they differed from one another in other respects. The IncC2 T16A mutant, predicted to be defective in Mg²? coordination, was severely impaired in all activities tested. IncC2 K10A, predicted to be defective in ATP hydrolysis, mediated enhanced incompatibility with R995 derivatives. IncC2 K15A, predicted to be defective in ATP binding, exhibited two distinct incompatibility properties depending on the genotype of the target plasmid. When in trans to plasmids carrying a complementable incC deletion, IncC2 K15A caused dramatic plasmid loss, even at low levels of expression. In trans to wild-type R995 or to R995?incC carrying a functional P1 partition system, IncC2 K15A-mediated incompatibility was significantly less than that caused by wild-type IncC2. All three Walker-like A box mutants were also defective for the host toxicity that normally results from co-overexpression of incC and korB. The phenotypes of the mutants support a model in which nucleotide hydrolysis is required for separation of paired plasmid complexes and possible interaction with a host factor. PMID:22579980

  17. An autosomal recessive limb girdle muscular dystrophy (LGMD2) with mild mental retardation is allelic to Walker–Warburg syndrome (WWS) caused by a mutation in the POMT1 gene

    Microsoft Academic Search

    Burcu Balci; Gökhan Uyanik; Pervin Dincer; Claudia Gross; Tobias Willer; Beril Talim; Göknur Haliloglu; Gülsev Kale; Ute Hehr; Jürgen Winkler; Haluk Topalo?lu

    2005-01-01

    Mutations of the protein O-mannosyltransferase (POMT1) gene affect glycosylation of ?-dystroglycan, leading to Walker–Warburg syndrome, a lethal disorder in early life with severe congenital muscular dystrophy, and brain and eye malformations. Recently, we described a novel form of recessive limb girdle muscular dystrophy with mild mental retardation, associated with an abnormal ?-dystroglycan pattern in the muscle, suggesting a glycosylation defect.

  18. Cancer cachexia and tumor growth reduction in Walker 256 tumor-bearing rats supplemented with N-3 polyunsaturated fatty acids for one generation.

    PubMed

    Togni, Valéria; Ota, Claudia C C; Folador, Alessandra; Júnior, O Tchaikovski; Aikawa, Júlia; Yamazaki, Ricardo K; Freitas, Fábio A; Longo, Rita; Martins, Edgair F; Calder, Philip C; Curi, Rui; Fernandes, Luiz C

    2003-01-01

    In this study we investigated the effect of lifelong supplementation of the diet with coconut oil (CO, rich in saturated fatty acids) or fish oil (FO, rich in n-3 polyunsaturated fatty acids, PUFAs) on tumor growth, animal survival, and metabolic indicators of cachexia in adult rats. Female Wistar rats were supplemented with CO or FO prior to mating and then throughout pregnancy and gestation, and then the male offspring were supplemented from weaning until 90 days of age. Then they were inoculated subcutaneously with Walker 256 tumor cells. Tumor weight at 14 days in control rats (those fed standard chow) was approximately 20 g. These animals displayed cancer cachexia, which was characterized by loss of weight, hypoglycemia, hyperlacticidemia, hypertriacylglycerolemia, and depletion of glycogen stores. Supplementation of the diet with CO did not change these parameters, except that there was a smaller decrease in serum triacylglycerol concentration. Supplementation of the diet with FO significantly decreased tumor growth (by approximately 60%), increased survival (50% at 30 days postinoculation vs. 30% in the controls and 13.5% in the CO group), and prevented the fall in body weight. Furthermore, FO supplementation partly abolished the fall in serum glucose, totally prevented the elevation in serum lactate concentrations, partly prevented the hypertriacylgylcerolemia, and preserved tissue glycogen stores. Lifelong consumption of FO, rich in n-3 PUFAs, protects against tumor growth and cancer cachexia and improves survival. PMID:12925304

  19. Dandy-Walker malformation and Wisconsin syndrome: novel cases add further insight into the genotype-phenotype correlations of 3q23q25 deletions

    PubMed Central

    2013-01-01

    Background The Dandy-Walker malformation (DWM) is one of the commonest congenital cerebellar defects, and can be associated with multiple congenital anomalies and chromosomal syndromes. The occurrence of overlapping 3q deletions including the ZIC1 and ZIC4 genes in few patients, along with data from mouse models, have implicated both genes in the pathogenesis of DWM. Methods and results Using a SNP-array approach, we recently identified three novel patients carrying heterozygous 3q deletions encompassing ZIC1 and ZIC4. Magnetic resonance imaging showed that only two had a typical DWM, while the third did not present any defect of the DWM spectrum. SNP-array analysis in further eleven children diagnosed with DWM failed to identify deletions of ZIC1-ZIC4. The clinical phenotype of the three 3q deleted patients included multiple congenital anomalies and peculiar facial appearance, related to the localization and extension of each deletion. In particular, phenotypes resulted from the variable combination of three recognizable patterns: DWM (with incomplete penetrance); blepharophimosis, ptosis, and epicanthus inversus syndrome; and Wisconsin syndrome (WS), recently mapped to 3q. Conclusions Our data indicate that the 3q deletion is a rare defect associated with DWM, and suggest that the hemizygosity of ZIC1-ZIC4 genes is neither necessary nor sufficient per se to cause this condition. Furthermore, based on a detailed comparison of clinical features and molecular data from 3q deleted patients, we propose clinical diagnostic criteria and refine the critical region for WS. PMID:23679990

  20. ATP Regulation of Type-1 Inositol 1,4,5-Trisphosphate Receptor Activity Does Not Require Walker A-type ATP-binding Motifs*

    PubMed Central

    Betzenhauser, Matthew J.; Wagner, Larry E.; Park, Hyung Seo; Yule, David I.

    2009-01-01

    ATP is known to increase the activity of the type-1 inositol 1,4,5-trisphosphate receptor (InsP3R1). This effect is attributed to the binding of ATP to glycine rich Walker A-type motifs present in the regulatory domain of the receptor. Only two such motifs are present in neuronal S2+ splice variant of InsP3R1 and are designated the ATPA and ATPB sites. The ATPA site is unique to InsP3R1, and the ATPB site is conserved among all three InsP3R isoforms. Despite the fact that both the ATPA and ATPB sites are known to bind ATP, the relative contribution of these two sites to the enhancing effects of ATP on InsP3R1 function is not known. We report here a mutational analysis of the ATPA and ATPB sites and conclude neither of these sites is required for ATP modulation of InsP3R1. ATP augmented InsP3-induced Ca2+ release from permeabilized cells expressing wild type and ATP-binding site-deficient InsP3R1. Similarly, ATP increased the single channel open probability of the mutated InsP3R1 to the same extent as wild type. ATP likely exerts its effects on InsP3R1 channel function via a novel and as yet unidentified mechanism. PMID:19386591

  1. Revision of the species of Jaliscoa Bou?ek within a review of the identity, relationships and membership of Jaliscoa, Catolaccus Thomson, Eurydinoteloides Girault, Lyrcus Walker and Trimeromicrus Gahan (Hymenoptera: Pteromalidae).

    PubMed

    Gibson, Gary A P

    2013-01-01

    The limits of Lyrcus Walker (1842), Catolaccus Thomson (1878), Eurydinoteloides Girault (1913a), Trimeromicrus Gahan (1914), and Jaliscoa Bou?ek (1993) are re-evaluated and redefined to better reflect observed distribution of morphological features. Nine of 13 New World species of Catolaccus are transferred to other genera and photographs of the primary type specimens are given to assist future recognition. New features are provided to assist identification of the remaining four Nearctic species of Catolaccus and these are compared to European species, with the observation that C. kansensis (Girault 1917c) could be a junior synonym of C. crassiceps (Masi 1911). Trimeromicrus is removed from synonymy under Lyrcus for the single species T. maculatus Gahan (1914) rev. comb. Newly synonymized under Lyrcus is the Australasian genus Neocylus Bou?ek (1988) n. syn. Ten species are newly transferred to Lyrcus-L. nigraeneus (Girault 1915) n. comb. (from Neocylus), L. helice (Walker 1843) n. comb. and L. cyaneus (Girault 1911) n. comb. (from Catolaccus), and L. albiclavus (Girault 1917c) n. comb., L. capitis (Burks 1955) n. comb., L. chalcis (Burks 1955) n. comb., L. coeliodis (Ashmead 1896) n. comb., L. deuterus (Crawford 1911) n. comb., L. nigroaeneus (Ashmead 1894a)n. comb. and L. rosaecolis (Burks 1955) n. comb. (from Zatropis Crawford 1908). Catolaccus pallipes Ashmead (1894b) is newly transferred to Pteromalus Swederus (1795) as Pteromalus pallipes (Ashmead) n. comb. and Catolaccus fragariae Rohwer (1934) to Lariophagus Crawford (1909) as Lariophagus fragariae (Rohwer) n. comb. Nine species are newly transferred to Eurydinoteloides-E. tepicensis (Ashmead 1895) n. comb. (from Catolaccus), E. dymnus (Walker 1847) n. comb., E. hermeas (Walker 1847) n. comb., E. incerta (Ashmead 1893) n. comb., E. orontas (Walker 1847) n. comb., E. perdubia (Girault 1916) n. comb., E. platensis (De Santis in De Santis et al. 1979) n. comb. and E. timaea (Walker 1847)n. comb. (from Lyrcus), and E. eudubia (Özdikmen 2011) n. comb. (from Spintherus Thomson 1878). Four species are newly transferred to Jaliscoa-J. grandis (Burks 1954) n. comb. and J. hunteri (Crawford 1908) n. comb. (from Catolaccus), and J. townsendi (Crawford 1912) n. comb. and J. vulgaris (Ashmead 1894b) n. comb. (from Pteromalus). The species of Jaliscoa are revised to include J. nudipennis Bou?ek 1993, J. bouceki n. sp., J. hunteri and J. vulgaris. Re-established in synonymy under J. hunteri is J. townsendi n. comb. One new species of Pteromalus, P. grisselli n. sp., is described as an egg predator in the egg sacs of Dictyna coloradensi Chamberlin (Araneae: Dictynidae) and compared to Catolaccus species and other pteromalids that are predators of spider eggs. Lectotypes are designated for Pteromalus helice Walker (1843), Catolaccus pallipes Ashmead (1894b) and Catolaccus vulgaris Ashmead (1894b). Diagnoses are given to differentiate Catolaccus, Eurydinoteloides, Jaliscoa, Lyrcus and Trimeromicrus from each other, and more extensive descriptions given to help differentiate these genera from other Pteromalinae. Morphological features are illustrated through macrophotography and scanning electron photomicrography. PMID:24699811

  2. High K volcanism in the Sierra Nevada: A signal for the initiation of Walker Lane Faulting, and range uplift, not lithosphere delamination

    NASA Astrophysics Data System (ADS)

    Putirka, K. D.; Busby, C. J.

    2007-12-01

    K2O contents have long been recognized as a potential indicator of tectonic processes, and based upon models developed for the Andes (Kay and Kay, 1993) and Tibet (Turner et al., 1996), high-K volcanism has been related to lithosphere delamination, by partial melting of a K-metasomatized lower crust or upper mantle (Feldstein and Lange, 1999; Manley et al., 2000). However, new data from the central Sierra Nevada cast doubt on this K2O-delamination link. Instead, high-K volcanism is better explained as low degree partial melts (F), where low F magmas are preferentially erupted over thick crust, under conditions of high tensile stress. In the central Sierra, a high tensile stress regime was imposed at the onset of Walker Lane transtension, at the eastern edge of the Basin and Range province. We surmise that high K volcanism is similarly controlled by the onset of tensile stresses throughout the Sierra, recording the initial phase of Sierra Nevada uplift. These conclusions stem from several observations. First, K2O contents are highly correlated with Th (R=0.82), Ba (R=0.83), U (R=0.85), Rb (R=0.88) and Pb (R=0.83), and other highly incompatible elements, suggesting a general enrichment mechanism, such as low degree partial melitng. Second, volcanic rocks with the highest K have the highest La/Nb and the lowest 143Nd/144Nd, indicative of a mantle lithosphere source - inconsistent with delamination. Third, maximum K contents increase from north (near Lassen) to south, following in increase in crustal thickness and the (87Sr/86Sr) i of basement granitoids, suggestive of a crustal control on volcanism. Finally, field evidence in the central Sierra shows that the pulse of high K2O volcanism there was synchronous with the development of a pull-apart, along a series of right-stepping dextral transtensional faults, at the onset of Walker Lane faulting. Partial melting calculations verify that primitive magma compositions from Lassen to the southern Sierra, can all be explained by partial melting of a single mantle source, with Cordilleran-type enrichments, but no special K enrichments in any particular region. Moreover, just as low F melts are enriched in K, Pb, or U, they will also be enriched in water, which greatly reduces magma density (Ochs and Lange, 1999). Such differences in water contents provide a mechanism for regional variations in volcanic compositions: depth-integrated density models show that dry mafic magmas have insufficient buoyancy to erupt from beneath thick crust, but low F (water-enriched) melts are sufficiently buoyant to allow eruption. Theoretical models (Takada, 1994) further indicate that tensile stress regimes favor the transport of low F melts. Thus, where the crust is thick, such as in the southern Sierra Nevada, only low F magmas can erupt, due to their natural water enrichments and added buoyancy, and even then are probably only erupted when tensile stresses favor their segregation from their source region. In our alternative interpretation then, high-K volcanism reflects the inception of transtensional stresses, recording the birth of a plate boundary.

  3. AP1S2 is mutated in X-linked Dandy-Walker malformation with intellectual disability, basal ganglia disease and seizures (Pettigrew syndrome).

    PubMed

    Cacciagli, Pierre; Desvignes, Jean-Pierre; Girard, Nadine; Delepine, Marc; Zelenika, Diana; Lathrop, Mark; Lévy, Nicolas; Ledbetter, David H; Dobyns, William B; Villard, Laurent

    2014-03-01

    MRXS5 or Pettigrew syndrome was described 20 years ago in a four generation family including nine affected individuals presenting with facial dysmorphism, intellectual disability, Dandy-Walker malformation and inconstant choreoathetosis. Four individuals had iron deposition in the basal ganglia seen on MRI or at autopsy. The mutation causing Pettigrew has remained elusive since the initial description of the condition. We report the identification of a mutation in the X-linked AP1S2 gene in the original Pettigrew syndrome family using X-chromosome exome sequencing. We report additional phenotype details for several of the affected individuals, allowing us to further refine the phenotype corresponding to this X-linked intellectual disability syndrome. The AP1S2 c.426+1?G>T mutation segregates with the disease in the Pettigrew syndrome family and results in loss of 46 amino acids in the clathrin adaptor complex small chain domain that spans most of the AP1S2 protein sequence. The mutation reported here in AP1S2 is the first mutation that is not predicted to cause a premature termination of the coding sequence or absence of the AP1S2 protein. Although most of the families affected by a mutation in AP1S2 were initially described as having different disorders assigned to at least three different OMIM numbers (MIM 300629, 300630 and 304340), our analysis of the phenotype shows that they are all the same syndrome with recognition complicated by highly variable expressivity that is seen within as well as between families and is probably not explained by differences in mutation severity. PMID:23756445

  4. Protrusive activity, cytoplasmic compartmentalization, and restriction rings in locomoting blebbing Walker carcinosarcoma cells are related to detachment of cortical actin from the plasma membrane.

    PubMed

    Keller, H; Eggli, P

    1998-01-01

    The dynamic events at the front of locomoting blebbing Walker carcinosarcoma cells [Keller and Bebie, Cell Motil. Cytoskeleton 33:241-251, 1996] are interpreted on the basis of an analysis of the actin cytoskeleton and its relationship to the plasma membrane in fixed cells using a novel double-staining procedure. The data show that blebs are formed where cortical actin is locally depolymerized and/or by detachment of the plasma membrane from more or less intact cortical actin layers. Dissociation between the cortical actin layer and the plasma membrane, which is stimulated by microtubule disassembly, is achieved by forward movement of the plasma membrane, rather than by retraction of the actin layer. Therefore, the detached actin layers form a boundary between the newly forming protrusions and the rest of the cell. They can be associated with "constriction rings," which we have termed "restriction rings." Detached actin layers can impede entry of organelles and the nucleus into the protrusions and thereby compartmentalize the cytoplasm. Later, detached cortical actin layers depolymerize, allowing for relaxation of the restriction rings and for forward movement of cytoplasmic organelles and the nucleus. Actin may repolymerize along the detached plasma membrane allowing for a new cycle to occur. Estimates indicate that the actin polymerization/depolymerization cycles may be largely confined to the front of blebbing cells. The findings suggest that the dynamic events at the front of blebbing metazoan cells are similar to those previously found in Amoeba proteus [Grebecki, Protoplasma, 154:98-111, 1990] but different from those found in lamellipodia. PMID:9786092

  5. Crustal deformation across the Sierra Nevada, northern Walker Lane, Basin and Range transition, western United States measured with GPS, 2000-2004

    NASA Astrophysics Data System (ADS)

    Hammond, William C.; Thatcher, Wayne

    2007-05-01

    Global Positioning System (GPS) data collected in campaigns in 2000 and 2004 were processed and interpreted with other GPS data in the western Basin and Range province to provide new constraints on the rate, style, and pattern of deformation of the central and northern Walker Lane (WL), which lies near the western boundary of the Basin and Range. Across the central WL, near 38°N latitude, the velocities with respect to North America increase westward by ˜10 mm/yr inducing dextral shear. Farther north between 40° and 41°N latitude, a western zone of ˜7 mm/yr relative motion undergoes dextral shear, and an eastern zone of ?3 mm/yr relative motion undergoes extension and shear. These data show that the northern WL is essentially a dextral shear zone experiencing minor net dilatation (?? = 2.6 ± 0.8 nstrain/yr). Near most Holocene normal faults, dilatation inferred from the velocity field is not greater than the uncertainties. However, near the central Nevada seismic belt we detect significant dilatation expressed as extension in a direction approximately normal to the range fronts (?? = 23.0 ± 3.9 nstrain/yr), some of which is attributable to transient postseismic deformation following large historic earthquakes. A block model constrained by velocities corrected for transient effects shows that the sum of dextral slip rates across the Honey Lake, Warm Springs, east Pyramid fault system, and Mohawk Valley faults is ˜7 mm/yr. The WL is a zone whose width and dilatation rate increase northwestward, consistent with counterclockwise rotation of the Sierra Nevada microplate and transfer of deformation into the Pacific Northwest.

  6. Multiple developmental programs are altered by loss of Zic1 and Zic4 to cause Dandy-Walker malformation cerebellar pathogenesis

    PubMed Central

    Blank, Marissa C.; Grinberg, Inessa; Aryee, Emmanuel; Laliberte, Christine; Chizhikov, Victor V.; Henkelman, R. Mark; Millen, Kathleen J.

    2011-01-01

    Heterozygous deletions encompassing the ZIC1;ZIC4 locus have been identified in a subset of individuals with the common cerebellar birth defect Dandy-Walker malformation (DWM). Deletion of Zic1 and Zic4 in mice produces both cerebellar size and foliation defects similar to human DWM, confirming a requirement for these genes in cerebellar development and providing a model to delineate the developmental basis of this clinically important congenital malformation. Here, we show that reduced cerebellar size in Zic1 and Zic4 mutants results from decreased postnatal granule cell progenitor proliferation. Through genetic and molecular analyses, we show that Zic1 and Zic4 have Shh-dependent function promoting proliferation of granule cell progenitors. Expression of the Shh-downstream genes Ptch1, Gli1 and Mycn was downregulated in Zic1/4 mutants, although Shh production and Purkinje cell gene expression were normal. Reduction of Shh dose on the Zic1+/?;Zic4+/? background also resulted in cerebellar size reductions and gene expression changes comparable with those observed in Zic1?/?;Zic4?/? mice. Zic1 and Zic4 are additionally required to pattern anterior vermis foliation. Zic mutant folial patterning abnormalities correlated with disrupted cerebellar anlage gene expression and Purkinje cell topography during late embryonic stages; however, this phenotype was Shh independent. In Zic1+/?;Zic4+/?;Shh+/?, we observed normal cerebellar anlage patterning and foliation. Furthermore, cerebellar patterning was normal in both Gli2-cko and Smo-cko mutant mice, where all Shh function was removed from the developing cerebellum. Thus, our data demonstrate that Zic1 and Zic4 have both Shh-dependent and -independent roles during cerebellar development and that multiple developmental disruptions underlie Zic1/4-related DWM. PMID:21307096

  7. E. L. Walker Curriculum vitae, page 1 ELSBETH L. WALKER

    E-print Network

    . of Biology Amherst, MA 01003 (413) 545-0861 voice; (413) 545-3243 fax email: ewalker@bio.umass.edu Date as a model system for the identification of optimal traits in plant cellulosic feedstocks for biofuels."$35) Identification and expression analysis of methyl jasmonate responsive ESTs in paclitaxel producing Taxus

  8. April 23, 2004 Mark Walker

    E-print Network

    ROLE The following is a response from Wells Rural Electric Company (WREC) to the April 8, 2004 draft tiered rates for the rate period beginning in FY 07. Our current contract with BPA runs through FY 11 resource/load environment and we feel that any tiered rates applied during the current contract period

  9. Daniel Walker 12 February 2014

    E-print Network

    Gray, Matthew

    White- A. transmontanus } 8 of 27 species of acipenserids } Lower conservation concern than Eurasian) Mayden & Kuhajda 1996 Klamath-Siskiyou Wildlands Center } Alabama- Endangered, 2000 } Atlantic- 4 DPS-Siskiyou Wildlands Center. Green sturgeon (Acipenser medirostris). http:// kswild.org/what-we-do-2/biodiversity

  10. Disease Precautions for Dog Walkers

    MedlinePLUS

    ... wind to unintended targets (such as other non-aggressive dogs or yourself), and use caution. The best ... dogs or dogs that you know have shown aggression toward people or other dogs. Make sure that ...

  11. October 3, 2006 Mark Walker

    E-print Network

    Funding Review Emerald People's Utility District (Emerald) is pleased to provide comments regarding the Councils F&W Program funding for Fiscal years 2007 ­ 2009. Emerald realizes the importance of preserving of providing low, cost-based power to our customers. Thus, Emerald appreciates the Council's efforts in working

  12. November 18, 2004 Mark Walker

    E-print Network

    the region working on the solution before the problem begins. 2. Climate Change. Because the climate change climate change. The plan touches on climate change, but never really explores the issue. 6-6. Climate are fully aware that climate change itself may be too uncertain to model and that regulatory responses

  13. October 5, 2006 Mark Walker

    E-print Network

    into the development of a turtle head-starting program here in Portland. Newly- hatched turtles are annually collected pond turtles (Clemmys marmorata) in the Columbia Gorge (NWPCC Project No. 200102700). Such an action of turtle recovery efforts during 2007-2009 would result in a 30% cut to the Oregon Zoo's annual western

  14. October 19, 2007 Mark Walker

    E-print Network

    emissions reductions that scientists believe are needed to avoid catastrophic global warming impacts. We-makers in the region. The paper clearly shows that the challenge of avoiding serious global warming impacts is great

  15. Robert Walker Sumner Curriculum Vitae

    E-print Network

    Sumner, Robert W.

    Institute of Technology 1993 Supercomputing Honors Program, Florida Delegate Lawrence Livermore National.S. in Electrical Engineering and Computer Science Massachusetts Institute of Technology, Cambridge, Massachusetts Laboratory for Computer Science 1994­1998 B.S. in Computer Science Georgia Institute of Technology, Atlanta

  16. 15 September 2006 Mark Walker

    E-print Network

    and recovery of white sturgeon throughout the Columbia River Basin. The outcome of this project throughout the Columbia River Basin is high in the Columbia and Snake Rivers Upstream from Bonneville Dam be terminated. The Council staff member's analysis

  17. September 29, 2006 Mark Walker

    E-print Network

    agencies decided a coordinated approach with multiple disciplines would be the most successful strategy Conservation District (UCD), United States Forest Service (USFS), United States Geological Survey (USGS of forest, monitored steelhead at different life history stages through out the watershed, and PIT tagged 4

  18. Walker, C. P., Maerz, N., and Hilgers, M. G. 2005. Surface reconstruction using shadow profilometry. Proceedings of the 2005 ACM Symposium on Applied Computing (Santa Fe, New Mexico, March 13 -17, 2005). L. M. Leibrock, Ed. SAC '05. ACM Press, New York,

    E-print Network

    Maerz, Norbert H.

    potential in application to post- disaster forensic investigations. The underlying concept is to reconstructWalker, C. P., Maerz, N., and Hilgers, M. G. 2005. Surface reconstruction using shadow profilometry. Leibrock, Ed. SAC '05. ACM Press, New York, NY, pp. 1250-1251. Surface Reconstruction Using Shadow

  19. The ontogeny of host-seeking behaviour in a parasitoid dipteran

    Microsoft Academic Search

    José E. Crespo; Marcela K. Castelo

    2008-01-01

    The robber fly Mallophora ruficauda is one of the principal apiculture pests in the Pampas region of Argentina. As adults, they prey on honeybees and other insects, while as larvae they are ectoparasitoids of third-instar scarab larvae. Females of M. ruficauda lay eggs in tall grasses. After being dispersed by the wind, larvae drop to the ground, where they dig

  20. Human small cell lung cancer NYH cells selected for resistance to the bisdioxopiperazine topoisomerase II catalytic inhibitor ICRF-187 demonstrate a functional R162Q mutation in the Walker A consensus ATP binding domain of the alpha isoform.

    PubMed

    Wessel, I; Jensen, L H; Jensen, P B; Falck, J; Rose, A; Roerth, M; Nitiss, J L; Sehested, M

    1999-07-15

    Bisdioxopiperazine drugs such as ICRF-187 are catalytic inhibitors of DNA topoisomerase II, with at least two effects on the enzyme: namely, locking it in a closed-clamp form and inhibiting its ATPase activity. This is in contrast to topoisomerase II poisons as etoposide and amsacrine (m-AMSA), which act by stabilizing enzyme-DNA-drug complexes at a stage in which the DNA gate strand is cleaved and the protein is covalently attached to DNA. Human small cell lung cancer NYH cells selected for resistance to ICRF-187 (NYH/187) showed a 25% increase in topoisomerase IIalpha level and no change in expression of the beta isoform. Sequencing of the entire topoisomerase IIalpha cDNA from NYH/187 cells demonstrated a homozygous G-->A point mutation at nucleotide 485, leading to a R162Q conversion in the Walker A consensus ATP binding site (residues 161-165 in the alpha isoform), this being the first drug-selected mutation described at this site. Western blotting after incubation with ICRF-187 showed no depletion of the alpha isoform in NYH/187 cells in contrast to wild-type (wt) cells, whereas equal depletion of the beta isoform was observed in the two sublines. Alkaline elution assay demonstrated a lack of inhibition of etoposide-induced DNA single-stranded breaks in NYH/187 cells, whereas this inhibition was readily apparent in NYH cells. Site-directed mutagenesis in human topoisomerase IIalpha introduced into a yeast Saccharomyces cerevisiae strain with a temperature-conditional yeast TOP2 mutant demonstrated that R162Q conferred resistance to the bisdioxopiperazines ICRF-187 and -193 but not to etoposide or m-AMSA. Both etoposide and m-AMSA induced more DNA cleavage with purified R162Q enzyme than with the wt. The R162Q enzyme has a 20-25% decreased catalytic capacity compared to the wt and was almost inactive at <0.25 mM ATP compared to the wt. Kinetoplast DNA decatenation by the R162Q enzyme at 1 mM ATP was not resistant to ICRF-187 compared to wt, whereas it was clearly less sensitive than wt to ICRF-187 at low ATP concentrations. This suggests that it is a shift in the equilibrium to an open-clamp state in the enzyme's catalytic cycle caused by a decreased ATP binding by the mutated enzyme that is responsible for bisdioxopiperazine resistance. PMID:10416608

  1. ________________________________________________________________________The MIND Institute__________________ Cheryl K. Walker, MD

    E-print Network

    Nguyen, Danh

    Professor, Department of Obstetrics and Gynecology, UC Davis School of Medicine Education BA, History, Smith and Gynecology, University of California, San Francisco, CA 1989 Fellowship in Reproductive Infectious Diseases Presentation, Infectious Disease Society for Obstetrics and Gynecology (IDSOG) , August, Chicago, IL. #12

  2. October 5, 2006 TO: Mark Walker

    E-print Network

    to comment on the 2007 BPA project draft Council recommendation list. It has been brought to my attention and also enhances the local economy. Project funds used for on the ground restoration activities are paid-cost alternatives to landowners for habitat restoration. Thank you for your attention to this matter. Sincerely

  3. undergraduate programs walker college of business

    E-print Network

    Thaxton, Christopher S.

    , retail, management consulting and health care firms. Entrepreneurship Focus Students majoring, civic leader, wife and mother of three, was a pioneer in the Florida citrus industry. As the owner of Raley Grove Properties for over 50 years, she was recognized as one of the top women citrus growers

  4. October 6, 2006 To: Mark Walker

    E-print Network

    by the Nez Perce Soil and Water Conservation District. I am requesting the Council to include these projects on the final recommendation list to BPA. Through these programs, the Nez Perce Soil and Water Conservation in the fisheries professions, including minorities and women. The Nez Perce Soil and Water Conservation District

  5. WALKER REPORTING SERVICE (724) 224-5282

    E-print Network

    US Army Corps of Engineers

    DISPOSAL AREA PROJECT PARKS TOWNSHIP PARKS TOWNSHIP VOLUNTEER FIRE DEPARTMENT DALMATIAN DRIVE VANDERGRIFT apologize for that. This meeting is all about communication. And dog gone it, I started it off with poorly

  6. Genetics Home Reference: Dandy-Walker syndrome

    MedlinePLUS

    ... absent or very small. Cysts form in the fourth ventricle, which is a fluid-filled cavity between ... macrocephaly). Affected individuals typically have intellectual disability that ranges from mild to severe, although some have a ...

  7. Mark E. Walker January 15, 2012

    E-print Network

    Logan, David

    faculty on this grant), June 1997 ­ May 2000; $30,030. 3. NSA Grant, "Algebraic K-theory and Motivic and Algebraic Geometry", (I was one of six faculty on this grant), July 2000 ­ June 2004; $45,936. 5. NSA Grant the vast majority of the writing of this proposal. 7. NSA Grant, "K-theory, Lawson Homology, and Hodge

  8. Mark E. Walker January 6, 2006

    E-print Network

    Walker, Mark

    ", (I was one of six faculty on this grant), June 1997 ­ May 2000; $30,030. 3. NSA Grant, "Algebraic K and Algebraic Geometry", (I was one of six faculty on this grant), July 2000 ­ June 2004; $45,936. 5. NSA Grant for this grant, not I. 7. NSA Grant, "K-theory, Lawson Homology, and Hodge Theory", January 2005 ­ December 2006

  9. Holography Without Photography Thad G. Walker

    E-print Network

    Walker, Thad G.

    only dark or transparent pixels output by a laser printer. The binary representation would work best/amplitude plate, computer-generated holography attempts to find a suitable binary encoding of the (complex is placed in front of a lens and illuminated by a plane wave of light, the Fraunhofer diffraction pat- tern

  10. Walker Branch WatershedWalker Branch Watershed LongLong--term hydrology, streamterm hydrology, stream

    E-print Network

    , stream ecology, biogeochemistry researchecology, biogeochemistry research Catchment waterCatchment water budgetsbudgets Stream metabolismStream metabolism and nutrient cyclingand nutrient cycling Algae, bryophytes

  11. Artificial Tribotactic Microscopic Walkers: Walking Based on Friction Gradients

    NASA Astrophysics Data System (ADS)

    Steimel, Joshua P.; Aragones, Juan L.; Alexander-Katz, Alfredo

    2014-10-01

    Friction, the resistive force between two surfaces sliding past each other, is at the core of a wide diversity of locomotion schemes. While such schemes are well described for homogeneous environments, locomotion based on friction in inhomogeneous environments has not received much attention. Here we introduce and demonstrate the concept of tribotaxis, a motion that is guided by gradients in the friction coefficient. Our system is composed of microwalkers that undergo an effective frictional interaction with biological receptors on the substrate, which is regulated by the density of such receptors. When actuated stochastically, microwalkers migrate to regions of higher friction, much like a chemotactic cell migrates to regions of higher chemoattractant concentration. Simulations and theory based on biased random walks are in excellent agreement with experiments. We foresee important implications for tribotaxis in artificial and natural locomotion in biological environments.

  12. Microscopic walkers in concentrated colloidal monolayers: Oscillators, rollers and spinners

    NASA Astrophysics Data System (ADS)

    Aragones, Juan Luis; Steimel, Joshua; Alexander-Katz, Alfredo

    2014-03-01

    We have studied the dynamical behavior of paramagnetic particles under a rotational magnetic field in concentrated passive colloidal monolayers, and their effects on the dynamics and structure of the monolayer. Depending on the direction of the applied rotating magnetic field, paramagnetic particles will rotate parallel or perpendicular to the substrate plane, generating two types of active particles: rollers, whose angular momentum is converted to translational motion through the force of friction between the particles and substrate, and spinners, which rotate parallel to the substrate. Additionally, oscillators can be created from rollers by applying oscillating magnetic fields. We have carried out experiments and simulations to analyze the dynamics of these active particles in dense colloidal monolayers. The non-equilibrium nature of these systems confers quite interesting behavior; we observed activity-induced phase separation and local vortex formation around rollers and spinners due to the fluid media. These vortices interact between them creating patterns and cooperative movements.

  13. Welty's "A Worn Path" and Walker's "Everyday Use": Companion Pieces.

    ERIC Educational Resources Information Center

    Byrne, Mary Ellen

    1989-01-01

    Examines two short stories by women writers--one Black and one White--which celebrate similar values and highlight Black women in family roles yet reveal differences in the authors' perspectives. (RAE)

  14. Recently promoted Associate Pro-fessor Jeffrey Walker has estab-

    E-print Network

    Walker, Jeff

    and the University of Mel- bourne congregated at the Leeton-Narrandera Airport in south-western NSW to conduct near around three themes: Research: Performance and implementation of Sustainable Systems strategy Education

  15. GeoFrame Walker Lane: Overview, Rationale, and Objectives

    Microsoft Academic Search

    D. F. Stockli

    2006-01-01

    GeoFrame is an integrative geologic initiative that takes a multi-dimensional view of the building and modification of the North American continent by systematic integration of geologic and geochronometric investigations and the results from unprecedented geophysical imaging as part of the Earthscope Program. The GeoFrame effort envisions these focus site investigations to entail map-scale arrays of passive source seismic receivers and

  16. GLOBAL BIFURCATION OF POSITIVE EQUILIBRIA IN NONLINEAR POPULATION CHRISTOPH WALKER

    E-print Network

    Walker, Christoph

    with nonlinear diffusion is investigated. Introducing a parameter measuring the intensity of the fertility by means of a fixed point theorem for conical shells. 1. INTRODUCTION This paper deals with finding nonlinear age-dependent diffusion (however, see [6, 15, 17, 26, 27]). To understand the asymptotic behavior

  17. How I do Knowledge Transfer Prof Peter Walker

    E-print Network

    Burton, Geoffrey R.

    , using conventional building materials and techniques the UK construction industry is struggling to meet in construction, but there is understandable resistance from the construction industry to do so. This stems from in modern construction industrial/stakeholder operations in the South- West renewable materials

  18. Dynamics of Robertson-Walker spacetimes with diffusion

    E-print Network

    Artur Alho; Simone Calogero; Maria P. Machado Ramos; Ana J. Soares

    2015-02-09

    We study the dynamics of spatially homogeneous and isotropic spacetimes containing a fluid undergoing microscopic velocity diffusion in a cosmological scalar field. After deriving a few exact solutions of the equations, we continue by analyzing the qualitative behavior of general solutions. To this purpose we recast the equations in the form of a two dimensional dynamical system and perform a global analysis of the flow. Among the admissible behaviors, we find solutions that are asymptotically de-Sitter both in the past and future time direction and which undergo accelerated expansion at all times.

  19. A Method for Creating Collaborative Mobile Learning Trails Kevin Walker

    E-print Network

    Paris-Sud XI, Université de

    and Levene (2003) and developed in the Kaleidoscope project 'Personal and collaborative trails of digital in the Kaleidoscope network, specifically in the following activities: · the Mobile Support for Integrated Learning Enhanced Learning SIG (which has focused on mobile learning); · The Kaleidoscope mobile learning initiative

  20. N.W.WALKER RD. N.W. HOLLY ST.

    E-print Network

    Chapman, Michael S.

    .......................................................... 7 Central Stores/Bioengineering Building 618 .......... 24 Cold Storage 628 ........................... 17 Saturday Academy Treehouse 680 ............................. 18 Staff Support Building (Locker/Shower

  1. Analysis of Transient Heating of Phosphor Coatings D. Greg Walker

    E-print Network

    Walker, D. Greg

    to this is interest in utilizing layers of thermal barrier coatings each doped with a different rare earth for turbine engine health monitoring purposes. The present work explores some issues associated with assessing

  2. College Orientation: Three Themes from Alice Walker's "The Color Purple."

    ERIC Educational Resources Information Center

    Osborne, Nancy Seale

    These four papers by a reference librarian discuss the potential for students at the State University of New York (SUNY) at Oswego to engage in a positive academic career that will have a significant impact not only on their growth as people, but also on their future endeavors. The first paper, "Self-Definition: Naming Yourself in a College…

  3. Walkers/Bikers Gopher Way Tunnels/Skyways

    E-print Network

    Minnesota, University of

    Comstock Hall Cooke Hall Diehl Hall Dinnaken Office Building Donhowe Dwan Cardiovascular/ Cancer Center Kolthoff Hall Lind Hall Lions Research Building / McGuire Translational Research Facility Mariucci Arena University Recreation Center Variety Club Research Center VFW Cancer Research Center Vincent Hall Walter

  4. Two World Walkers: The Eagles in Aerospace Program.

    ERIC Educational Resources Information Center

    Stark, Jason

    1997-01-01

    The Nez Perce council, NASA, and the University of Idaho initiated a program that enables Native American students to identify and correspond with Native American professionals in aeronautical careers who are willing to mentor these students. The goal is to move academia and academic programs into the realm of Native American identity, ideology,…

  5. ROBERT M. WALKER February 6, 1929-February 12, 2004

    E-print Network

    Price, P. Buford

    . During the depression, when there were few jobs, the three of them moved to a farm near Cobleskill, New during the depression was challenging. He had to walk a mile, sometimes in blizzard conditions, to catch% girls. Bob learned that he could excel at science in a dog-eat-dog environment. From the age of three

  6. Editor's Comments "Salt-Walkers"; Summing Up '73

    E-print Network

    I that the "shrimp number" (1\\Iarch- April) m ight be widely read. but I did not expect al l the copies to disappear Stein berg's paper o n aqua- culture appea rs to ha\\e bee n \\\\ iLiel) read. T o li st th ese pa pers

  7. A hexapod walker using a heterarchical architecture for action selection

    PubMed Central

    Schilling, Malte; Paskarbeit, Jan; Hoinville, Thierry; Hüffmeier, Arne; Schneider, Axel; Schmitz, Josef; Cruse, Holk

    2013-01-01

    Moving in a cluttered environment with a six-legged walking machine that has additional body actuators, therefore controlling 22 DoFs, is not a trivial task. Already simple forward walking on a flat plane requires the system to select between different internal states. The orchestration of these states depends on walking velocity and on external disturbances. Such disturbances occur continuously, for example due to irregular up-and-down movements of the body or slipping of the legs, even on flat surfaces, in particular when negotiating tight curves. The number of possible states is further increased when the system is allowed to walk backward or when front legs are used as grippers and cannot contribute to walking. Further states are necessary for expansion that allow for navigation. Here we demonstrate a solution for the selection and sequencing of different (attractor) states required to control different behaviors as are forward walking at different speeds, backward walking, as well as negotiation of tight curves. This selection is made by a recurrent neural network (RNN) of motivation units, controlling a bank of decentralized memory elements in combination with the feedback through the environment. The underlying heterarchical architecture of the network allows to select various combinations of these elements. This modular approach representing an example of neural reuse of a limited number of procedures allows for adaptation to different internal and external conditions. A way is sketched as to how this approach may be expanded to form a cognitive system being able to plan ahead. This architecture is characterized by different types of modules being arranged in layers and columns, but the complete network can also be considered as a holistic system showing emergent properties which cannot be attributed to a specific module. PMID:24062682

  8. Advanced Auditory Menus Pavani Yalla & Bruce N. Walker

    E-print Network

    ..................................................................19 3.2.1 Auditory Icons 19 3.2.2 Earcons 20 3.2.3 Spearcons 21 3.2.4 Sonification in Mobile Phones 22.3.1 Outputs of Menu Selection 10 2.3.2 Components of Menu Selection 10 2.4 Designing Menus to designing auditory menus. This report is a summary of some of the findings from the literature review

  9. A Robotic Walker That Provides Guidance Aaron Morris

    E-print Network

    Thrun, Sebastian

    localization and navi- gation combined with a shared-control haptic interface. The system has been tested-to-human interaction. Escorting the elderly who reside in long term care settings to medical (doctor and therapy appointments), social (meeting friends), and cosmetic (manicure, getting a hair cut) activities, as well

  10. Artificial tribotactic microscopic walkers: walking based on friction gradients.

    PubMed

    Steimel, Joshua P; Aragones, Juan L; Alexander-Katz, Alfredo

    2014-10-24

    Friction, the resistive force between two surfaces sliding past each other, is at the core of a wide diversity of locomotion schemes. While such schemes are well described for homogeneous environments, locomotion based on friction in inhomogeneous environments has not received much attention. Here we introduce and demonstrate the concept of tribotaxis, a motion that is guided by gradients in the friction coefficient. Our system is composed of microwalkers that undergo an effective frictional interaction with biological receptors on the substrate, which is regulated by the density of such receptors. When actuated stochastically, microwalkers migrate to regions of higher friction, much like a chemotactic cell migrates to regions of higher chemoattractant concentration. Simulations and theory based on biased random walks are in excellent agreement with experiments. We foresee important implications for tribotaxis in artificial and natural locomotion in biological environments. PMID:25379939

  11. HIGH RESOLUTION AIRBORNE SOIL MOISTURE MAPPING Jeffrey Walker1

    E-print Network

    Walker, Jeff

    farms [1]. This is the first airborne remote sensing study to provide such high resolution soil moisture microwave remote sensing provides a viable tool for high resolution soil moisture mapping across large areas. #12;Figure 2: Time sequence of remotely sensed (top 2 rows) and ground measured (bottom 2 rows) soil

  12. Design Issues and Applications for a Passive-Dynamic Walker

    Microsoft Academic Search

    Kalin Trifonov; Guillermo Enriquez; Shuji Hashimoto

    2009-01-01

    Humanoid and walking robots have been widely developed and their use in human environments is not far out of reach. The main problems in practical applications of machine walking are energy consumption, complex control and design, and high cost. The main feasible indoor application of a walking machine is that of a humanoid robot as a companion, nurse, guide, or

  13. Cosmological Principle & The Robertson-Walker Metric September 13, 2007

    E-print Network

    Weijgaert, Rien van de

    Cosmology Gravity is ruling the Universe. It was Newton who was the first to establish this. Following formulated his theory of gravity. On the basis of his theory the first true scientific cosmological of Relativity, which explained gravity in a different way from Newton's law. Gravity was a manifestation

  14. October 11, 2006 Mr. Mark Walker, Director of Public Affairs

    E-print Network

    and capitalizing three projects (Walla Walla Juvenile and Adult Passage Improvements, Gardena Farms Irrigation District Irrigation Efficiency and Instream Flow, and Restore Walla Walla River Flow). The second scenario is based on adding the Touchet Eastside and Westside Irrigation District Piping project to those three

  15. Eulerian Walkers as a Model of Self-Organized Criticality

    Microsoft Academic Search

    V. B. Priezzhev; Deepak Dhar; Abhishek Dhar; Supriya Krishnamurthy

    1996-01-01

    We propose a new model of self-organized criticality. A particle is dropped at random on a lattice and moves along directions specified by arrows at each site. As it moves, it changes the direction of the arrows according to fixed rules. On closed graphs these walks generate Euler circuits. On open graphs, the particle eventually leaves the system, and a

  16. Flight morphology of Neotropical butterflies: palatability and distribution of mass to the thorax and abdomen

    Microsoft Academic Search

    Robert B. Srygley; Peng Chai

    1990-01-01

    We test whether palatability of Neotropical butterflies is associated with distribution of mass to the thorax and abdomen. Thoracic mass is predominantly muscle mass, whereas abdominal mass includes organs of digestion, food storage, and reproduction. To escape from predation, butterflies palatable to the rufous-tailed jacamar (Galbula ruficauda) use fast, erratic flight, whereas unpalatable butterflies have defensive chemicals and slow, regular

  17. Thinking While Walking: Experienced High-Heel Walkers Flexibly Adjust Their Gait

    PubMed Central

    Schaefer, Sabine; Lindenberger, Ulman

    2013-01-01

    Theories of motor-skill acquisition postulate that attentional demands of motor execution decrease with practice. Hence, motor experts should experience less attentional resource conflict when performing a motor task in their domain of expertise concurrently with a demanding cognitive task. We assessed cognitive and motor performance in high-heel experts and novices who were performing a working memory task while walking in gym shoes or high heels on a treadmill. Surprisingly, neither group showed lower working memory performance when walking than when sitting, irrespective of shoe type. However, high-heel experts adapted walking regularity more flexibly to shoe type and cognitive load than novices, by reducing the variability of time spent in the single-support phase of the gait cycle in high heels when cognitively challenged. We conclude that high-heel expertise is associated with more flexible adjustments of movement patterns. Future research should investigate whether a more demanding walking task (e.g., wearing high heels on uneven surfaces and during gait perturbations) results in expertise-related differences in the simultaneous execution of a cognitive task. PMID:23760158

  18. Responses of the adult almond moth, (Ephestia cautella (Walker)) to intermittent near ultraviolet radiation stimuli 

    E-print Network

    Hollingsworth, Joe Pettus

    1961-01-01

    of radiation were special coiled filament tungsten lamps, Oeneral Electric Company type 18A/T10/4 . This type of lamp has an envelope made of a material which transmits a relatively high percentage of radiation in the near ultra- violet region...RESPONSES OF THE kDULT ALNOND MOTHp (EPHESTIk CkUTELLA (WAILER)) TO INTERMITTENT NEAR ULTRAVIOLET RADIATION STINULI A Thesis JOSEPH PETTUS HOLLINGSWORTH Suhaitted to the Oraduate Sohool of the Agricultural and Mechanioal College of Texas...

  19. Quantum nature of the hydrogen bond Xin-Zheng Li, Brent Walker, and Angelos Michaelides1

    E-print Network

    Weeks, Eric R.

    from a competition between anharmonic intermolecular bond bending and intramolecular bond stretching materials. Furthermore, it high- lights the need to allow flexible molecules when anharmonic potentials-bonded systems in exquisite detail. The relevance of quantum nuclear effects (QNEs) to liquid water and ice (3

  20. A Phase I Cultural Resources Survey of the Walker County Jail and Office Expansion Area Project 

    E-print Network

    Moore, William

    2015-06-08

    of Southeast Texas begins with the Paleo-Indian period (circa 10,000 B.C. - 6000 B.C.). This is followed by the Archaic period (6000 B.C. - 2000 B.C.), the Early Ceramic period (200 B.C. - A.D. 700), the Late Ceramic period (A.D. 700 - A.D. 1700...), and the Historic period which documents those events following contact with native Indian groups by European explorers and later settlers to the present. Shafer, although in agreement with these dates, refers to the Paleo-Indian and Archaic periods as the Early...

  1. Hybrid Geometric Feedback Control of Three-Dimensional Bipedal Robotic Walkers with Knees and Feet

    E-print Network

    Sinnet, Ryan Wesley

    2012-07-16

    ) . . . . . . . . . . . . . . . . . . . . . . 56 3. Domain 3 (kl) . . . . . . . . . . . . . . . . . . . . . . 56 4. Domain 4 (hs) . . . . . . . . . . . . . . . . . . . . . . 57 D. Two-Dimensional Simulation Results . . . . . . . . . . . . 58 VI FUNCTIONAL ROUTHIAN REDUCTION...) . . . . . . . . . . . . . . . . . . . . . . 75 4. Domain 4 (hs) . . . . . . . . . . . . . . . . . . . . . . 76 5. 3 D Simulation Results . . . . . . . . . . . . . . . . . . 77 VIII CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 REFERENCES...

  2. Random walker in temporally deforming higher-order potential forces observed in a financial crisis.

    PubMed

    Watanabe, Kota; Takayasu, Hideki; Takayasu, Misako

    2009-11-01

    Basic peculiarities of market price fluctuations are known to be well described by a recently developed random-walk model in a temporally deforming quadratic potential force whose center is given by a moving average of past price traces [M. Takayasu, T. Mizuno, and H. Takayasu, Physica A 370, 91 (2006)]. By analyzing high-frequency financial time series of exceptional events, such as bubbles and crashes, we confirm the appearance of higher-order potential force in the markets. We show statistical significance of its existence by applying the information criterion. This time series analysis is expected to be applied widely for detecting a nonstationary symptom in random phenomena. PMID:20365046

  3. SUPPORTING ONLINE MATERIAL Efficient bipedal robots based on passive-dynamic walkers

    E-print Network

    Collins, Steven H.

    learning biped. This movie begins with the powered robot imitating passive walking down a 0.9 degree slope, from three camera angles. Then it shows the robot learning to walk on flat terrain with foam protective walking on flat ground. A slow-motion segment shows the ankle push- off actuation. S2 Delft pneumatic

  4. Tightrope Walkers and Solidarity Sisters: Critical Workplace Educators in the Garment Industry

    ERIC Educational Resources Information Center

    Fenwick, Tara

    2007-01-01

    This article focuses on the complex negotiations of critical workplace educators positioned amongst contradictory agendas and discourses in the workplace. While philosophically aligned with critical pedagogical agendas of transformation and collective action for workplace change, these educators perform an array of pedagogic articulations in…

  5. The National Airborne Field Experiment Data Sets Walker J.P. 1

    E-print Network

    Walker, Jeff

    with intensive ground and airborne measurements of the appropriate type and spatial/temporal resolution. While-band Multibeam Radiometer (PLMR), a thermal imager, full-wave transform lidar, tri-spectral scanner and digital camera were flown onboard a small aircraft, together with coincident ground data collection on soil

  6. Brownian motion in Robertson-Walker spacetimes from electromagnetic vacuum fluctuations

    SciTech Connect

    Bessa, Carlos H. G. [Departamento de Fisica, Universidade Federal da Paraiba, Joao Pessoa, Paraiba 58051-970 (Brazil); Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States); Bezerra, V. B. [Departamento de Fisica, Universidade Federal da Paraiba, Joao Pessoa, Paraiba 58051-970 (Brazil); Ford, L. H. [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States)

    2009-06-15

    We consider the effects of the vacuum fluctuations of a quantized electromagnetic field on particles in an expanding universe. We find that these particles typically undergo Brownian motion and acquire a nonzero mean squared velocity that depends on the scale factor of the universe. This Brownian motion can be interpreted as due to noncancellation of anticorrelated vacuum fluctuations in the time-dependent background spacetime. Alternatively, one can interpret this effect as the particles acquiring energy from the background spacetime geometry, a phenomenon that cannot occur in a static spacetime. We treat several types of coupling between the electromagnetic field and the particles and several model universes. We also consider both free particles, which, on the average, move on geodesics, and particles in bound systems. There are significant differences between these two cases, which illustrates that nongeodesic motion alters the effects of the vacuum fluctuations. We discuss the possible applications of this Brownian motion effect to cosmological scenarios.

  7. Directional Dynamic Covalent Motion of a Carbonyl Walker on a Polyamine Track.

    PubMed

    Kova?í?ek, Petr; Lehn, Jean-Marie

    2015-06-22

    Controlled directional displacement of a molecular group has been achieved based on dynamic covalent motions implementing the reactional features of the imine bond. ortho-Carboxybenzaldehyde derivatives are able to form stable adducts with both primary and secondary amines as imines or as amino lactones, respectively, depending on the acidity of the medium. They may thus perform pH-driven intramolecular "walking" along a non-symmetric polyamine chain, in which an imine serves as the terminus under basic conditions on one end of the chain and a lactone formed on a secondary hydroxylamine nitrogen on the other end serves as the terminal site upon addition of acid. The displacement between the termini occurs stochastically through reversible change in valency at the carbon site of the carbonyl group between imine, aminal, iminium and amino lactone form. On the other hand, the directionality results from the stabilisation of the terminal products under given pH conditions. By its ability to undergo interconversion between C?N and O-C-N moieties, the ortho-carboxybenzaldehyde group extends the realm of dynamic covalent chemistry of imines to secondary amines and opens new perspectives in this field. PMID:26017688

  8. A Phase I Cultural Resources Survey of the Walker County Jail and Office Expansion Area Project

    E-print Network

    Moore, William

    2015-06-08

    , Cottontail rabbit, Swamp rabbit, Grey squirrel, Fox squirrel, Flying squirrel, Raccoon, Opossum, Red fox, Grey fox, Woodchuck, Bobcat, Spotted skunk, Striped skunk, Mink, Otter, Long-tailed weasel, and Muskrat. According to Ippolito (1983:11), this list... to exist. Caddoan pottery types are present and suggest interaction between the two groups. 11 Subsistence patterns in the Caddoan area now included horticulture with such crops as corn, bean, and squash being commonly grown. Although...

  9. The Excess of Small Inverted Repeats in Prokaryotes Emmanuel D. Ladoukakis Adam Eyre-Walker

    E-print Network

    Eyre-Walker, Adam

    The Excess of Small Inverted Repeats in Prokaryotes Emmanuel D. Ladoukakis Æ Adam Eyre to a genuine difference between prokaryotes and eukaryotes or to differences in the methods and types of data of inverted repeats, which is much lower than previously reported in whole prokaryotic genomes. This suggests

  10. Directional Dynamic Covalent Motion of a Carbonyl Walker on a Polyamine Track.

    PubMed

    Kova?í?ek, Petr; Lehn, Jean-Marie

    2015-06-22

    Invited for the cover of this issue is the group of Jean-Marie Lehn at the Université de Strasbourg (France). The image depicts the trend of the research activities pursued in our laboratory in Strasbourg over 50 years towards chemical systems, entities and processes, of increasing complexity. Read the full text of the article at 10.1002/chem.201500987. PMID:26014159

  11. Parallelized direct search of a binary objective P. Grant and D.G. Walker

    E-print Network

    Walker, D. Greg

    -linear speedup up to 16 processors for most functions. 1 Introduction Engineering analysis is often concerned with identifying conditions responsible for catastrophic failure. For example, consider the load required to buckle a column. Using simple materials relations and static analysis, an estimate can be obtained for a range

  12. In "Centering in Discourse", Oxford University Press, Walker, Joshi, Prince editors, 1998

    E-print Network

    Di Eugenio, Barbara

    in Italian Barbara Di Eugenio Learning Research and Development Center University of Pittsburgh Pittsburgh and different forms of pronominal refer­ ence in Italian, in particular zeros and overt pronouns in subject, and in CONTINUE's preceded by a RETAIN. 1 Introduction Italian is a pro­drop language, in that the subject

  13. Walker Prize Lecture, 1977. Choriocarcinoma: can we afford to cure cancer.

    PubMed Central

    Bagshawe, K. D.

    1978-01-01

    The way the management of patients with trophoblastic tumours has depended on the acquisition of new knowledge and new drugs is demonstrated. Emphasis is put on the ability to detect early disease by biochemical markers and on the ability to define on a multifactorial basis the resistance potential of the tumours. This provides a basis for stratification of treatment and the use of prophylactic chemotherapy to prevent cerebral metastases in certain patients. Although chemotherapy is often intensive and prolonged, there has so far been little evidence of long-term effects and many women have had normal pregnancies subsequently, but the limitations of present data are discussed. The difficulties of matching available resources to society's needs in the cancer field make it necessary to consider whether such treatment is unjustifiably expensive. It is shown that for these tumours early diagnosis not only proves effective in therapeutic terms but provides substantial financial savings. It is suggested that screening programmes for cancer cannot be accepted or rejected on principle. In judging them on their individual merits it is appropriate to anticipate interaction between earlier diagnosis and more effective drug treatment. PMID:626471

  14. EFFICIENT TRAITOR TRACING ALGORITHMS USING LIST DECODING ALICE SILVERBERG, JESSICA STADDON, AND JUDY WALKER

    E-print Network

    in the system is associated with a unique set of symbols. For example, the sets may be used to install on methods for constructing such traceability schemes, but the complexity of the traitor tracing algorithms a running time of O(N) in general, where N is number of sets in the system (e.g., the number of copies

  15. Unsung Heroes: The Leaders in Our Classrooms. The William Walker Oration, 1996.

    ERIC Educational Resources Information Center

    Crowther, Frank

    1997-01-01

    Uses outcomes of case study research in socioeconomically disadvantaged education contexts to examine accomplishments of (Australian) educators who have significantly affected their communities' quality of life. Highly successful classroom practitioners' work has some connection with prominent educational leadership theories. Questions approaches…

  16. Kinematic and Mechanical Reconstruction of Walker Ridge Structures, Deepwater Gulf of Mexico

    E-print Network

    Majekodunmi, Oluwatosin Eniola

    2011-02-22

    , starting in the early Cretaceous, was produced by salt withdrawal, and (3) periods of increased sedimentation, fold growth, and fault slip occurred during the middle Miocene and late Miocene. Although the dominant stage of long wavelength, large amplitude...

  17. Spatial Raman solitons D. D. Yavuz, D. R. Walker, and M. Y. Shverdin

    E-print Network

    Yavuz, Deniz

    . This variation in the refractive index can cause self-focusing or self-defocusing of the driving lasers coherence such that the effects of diffraction will be exactly canceled by Raman self-focusing bright-mode laser fields whose frequency difference is slightly detuned from the Raman resonance. When

  18. Kinematic and Mechanical Reconstruction of Walker Ridge Structures, Deepwater Gulf of Mexico 

    E-print Network

    Majekodunmi, Oluwatosin Eniola

    2011-02-22

    ) of favored and minimum deformation rates for the Mediano anticline, Southern Pyrenees ................................................................................................. 34 Figure 2. Summary of the evolution... salt deformation. The interval of slow growth was punctuated by periods of rapid growth with limb tilt estimated at 10?- 40?/Ma (Figure 1) due to tectonic compression from the episodic, westward advance of the Cotiella-Montsec thrust sheet (Figure 2...

  19. 24. Walker MM, Talley NJ. Functional gastrointestinal disorders and the potential role of eosinophils.

    E-print Network

    Brenner, David Jonathan

    is the radiation exposure produced by the CT scan. By their nature, CT scans result in radiation doses which are very much at the high end of those produced in diagnostic radiology, simply because a CT scan-dimensional image. The effective dose involved in a CT scan is not large, but it is typically two to six times

  20. Evidence of a spring rise in metabolic rate in the burrowing mayfly ephemera simulans Walker

    Microsoft Academic Search

    C. H. Eriksen

    1964-01-01

    Ephemera simulans maintains an oxygen consumption in a suitable substratum (Ø-1) of approximately 0.23 cc\\/g\\/hr from at least February, and probably before, through approximately the middle of April at which time it rises to around 0.37 cc\\/g\\/hr (Table I). Such data indicate quite clearly that a rise in metabolic rate occurs in the spring in this burrowing mayfly. A surge

  1. Controlled surface-induced flows from the motion of self-assembled colloidal walkers

    E-print Network

    Sing, Charles E.

    Biological flows at the microscopic scale are important for the transport of nutrients, locomotion, and differentiation. Here, we present a unique approach for creating controlled, surface-induced flows inspired by a ...

  2. Controlled surface-induced flows from the motion of self-assembled colloidal walkers

    PubMed Central

    Sing, Charles E.; Schmid, Lothar; Schneider, Matthias F.; Franke, Thomas; Alexander-Katz, Alfredo

    2010-01-01

    Biological flows at the microscopic scale are important for the transport of nutrients, locomotion, and differentiation. Here, we present a unique approach for creating controlled, surface-induced flows inspired by a ubiquitous biological system, cilia. Our design is based on a collection of self-assembled colloidal rotors that “walk” along surfaces in the presence of a rotating magnetic field. These rotors are held together solely by magnetic forces that allow for reversible assembly and disassembly of the chains. Furthermore, rotation of the magnetic field allows for straightforward manipulation of the shape and motion of these chains. This system offers a simple and versatile approach for designing microfluidic devices as well as for studying fundamental questions in cooperative-driven motion and transport at the microscopic level. PMID:20080716

  3. On the relevance of q-distribution functions: The return time distribution of restricted random walker

    E-print Network

    Jaleh Zand; Ugur Tirnakli; Henrik Jeldtoft Jensen

    2015-06-11

    There exist a large literature on the application of $q$-statistics to the out-of-equilibrium non-ergodic systems in which some degree of strong correlations exists. Here we study the distribution of first return times to zero, $P_R(0,t)$, of a random walk on the set of integers $\\{0,1,2,...,L\\}$ with a position dependent transition probability given by $|n/L|^a$. We find that for all values of $a\\in[0,2]$ $P_R(0,t)$ can be fitted by $q$-exponentials, but only for $a=1$ is $P_R(0,t)$ given exactly by a $q$-exponential in the limit $L\\rightarrow\\infty$. This is a remarkable result since the exact analytical solution of the corresponding continuum model represents $P_R(0,t)$ as a sum of Bessel functions with a smooth dependence on $a$ from which we are unable to identify $a=1$ as of special significance. However, from the high precision numerical iteration of the discrete Master Equation, we do verify that only for $a=1$ is $P_R(0,t)$ exactly a $q$-exponential and that a tiny departure from this parameter value makes the distribution deviate from $q$-exponential. Further research is certainly required to identify the reason for this result and also the applicability of $q$-statistics and its domain.

  4. WHAT CAN CASUAL WALKERS TELL US ABOUT A 3D SCENE? Diego Rother

    E-print Network

    exploit the presence of casual people walking in the scene to infer relative depth, learn shadows cameras provide a large amount of video data containing people walking casually in a scene. Processing of such data (for tracking, segmentation, foreground refinement, etc) can benefit tremendously from 3D scene

  5. This article was downloaded by:[Walker, Andrew] On: 18 November 2007

    E-print Network

    of Contemporary Asia Publication details, including instructions for authors and subscription information: http representation that the contents will be complete or accurate or up to date. The accuracy of any instructions

  6. Bouquet: a Satellite Constellation Visualization Program for Walkers and Lattice Flower Constellations

    E-print Network

    Enkh, Mandakh

    2011-10-21

    Page 2-1 Relative and Inertial Trajectories of a Molniya Orbit ................................ 3 2-2 Constellation with RAAN Varied Inertial Orbits ....................................... 4 2-3 Constellation with a Single Inertial Orbit... .............................................................. 45 5-3 Difference of True Anomaly between STK and Bouquet .......................... 49 5-4 Inertial Position Vector Error Testing ........................................................ 50 5-5 Inertial Velocity Vector Error Testing...

  7. Random walkers with extreme value memory: modelling the peak-end rule

    E-print Network

    Harris, Rosemary J

    2015-01-01

    Motivated by the psychological literature on the "peak-end rule" for remembered experience, we perform an analysis within a random walk framework of a discrete choice model where agents' future choices depend on the peak memory of their past experiences. In particular, we use this approach to investigate whether increased noise/disruption always leads to more switching between decisions. Here extreme value theory illuminates different classes of dynamics indicating that the long-time behaviour is dependent on the scale used for reflection; this could have implications, for example, in questionnaire design.

  8. Neurocutaneous melanosis and the Dandy–Walker complex: an uncommon but not so insignificant association

    Microsoft Academic Search

    Dominique Marnet; Matthieu Vinchon; Keyvan Mostofi; Benoit Catteau; Olivier Kerdraon; Patrick Dhellemmes

    2009-01-01

    Background  Neurocutaneous melanosis represents a rare congenital but nonheritable phakomatosis defined as the association of giant or\\u000a multiple congenital nonmalignant melanocytic nevi with leptomeningeal melanosis or melanoma of the central nervous system.\\u000a \\u000a \\u000a \\u000a Methods  We describe the case of an adolescent with a giant congenital bathing trunk melanocytic nevus who developed progressive intracranial\\u000a hypertension due to leptomeningeal melanosis confirmed by surgical biopsy. Brain

  9. Transcription Elongation: TLKing to T. Keith Blackwell and Amy K. Walker

    E-print Network

    Blackwell, Keith

    , of the nematode Caenorhabdi- tis elegans during embryogenesis. A significant fraction of tlk-1(RNAi) embryos, Han et al. [7] have now used RNA interference (RNAi) to study the single TLK gene, tlk-1 for the kinase. Neither RNAi nor in vitro experiments, however, gave any indication that C. elegans TLK-1

  10. Bounding Algorithms for Design Space Exploration \\Lambda Samit Chaudhuri Robert A. Walker

    E-print Network

    Walker, Robert A.

    of all operations be denoted as fo i j i 2 Ig, where I is the index set of all operations. Let asap i) into which operation o i can start execution. The cstep interval S i = [asap i ; alap i ] is then referred constraints, to en­ sure that each operation o i is scheduled within its schedule interval [asap i ; alap i

  11. From a Five Dimensional Warped Friedmann-Robertson-Walker Universe to the Weyl Integrable Spacetime

    NASA Astrophysics Data System (ADS)

    Dariescu, Marina-Aura; Dariescu, Ciprian

    2015-07-01

    The present work intends to point out similarities between the theory developed on a ( k = 0)-FRW brane embedded in a five dimensional bulk and significant results derived within the Weyl integrable geometry.

  12. Greg Walker, PhD Regius Professor of Rhetoric and English Literature

    E-print Network

    Swain, Peter

    University of Aberdeen 2.30 pm Scottish Poetry Library Tour Thursday 10 10.00 am Who is Speaking in Mrs and Nineteen Eighty-Four DR ALEXANDRA LAWRIE English Literature, University of Edinburgh 2.30 pm International School of English, University of Aberdeen 8.00 pm Farewell Party 7 July - 16 August Text and Context Week

  13. Bouquet: a Satellite Constellation Visualization Program for Walkers and Lattice Flower Constellations 

    E-print Network

    Enkh, Mandakh

    2011-10-21

    The development of the Flower Constellation theory offers an expanded framework to utilize constellations of satellites for tangible interests. To realize the full potential of this theory, the beta version of Bouquet was developed as a practical...

  14. Turning nickels into dollars: maggie walker and the consolidated bank and trust company

    Microsoft Academic Search

    John Trinkaus; Alvin Puryear

    1997-01-01

    While many are familiar with the history of banking in the United States, relatively few know of its development in the African American community. Following the failure of the Freedman's Bank, shortly after its inception at the close of the Civil War, many African American fraternal organizations expanded their scope of interests to try to fill the void. The intent

  15. Navel Orangeworm (Amyelois transitella) (Walker) and Obliquebanded Leafroller (Choristoneura rosaceana)(Harris) as Pests of Pistachio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The navel orangeworm moved into California in 1942 from Mexico and by 1949 was present throughout the state. This moth is the primary pest of pistachios and almonds in California and causes direct damage by feeding on the kernel. Infestation reduces yield, increases aflatoxin contamination, primaril...

  16. Immune response of Chilo suppressalis Walker (Lepidoptera: Crambidae) larvae to different entomopathogenic fungi.

    PubMed

    Zibaee, A; Malagoli, D

    2014-04-01

    The current study reports mortality and effects on cellular immune response of several entomopathogenic fungi including isoleates BB1, BB2 and BB3 of Beauveria bassiana, Metarhizium anisopliae, Isaria fumosoroseus and Lecanicilium lecanii against larvae of Chilo suppressalis. Prohemocytes, granulocytes, plasmatocytes and oenocytoids were identified as the main circulating hemocytes in the hemolymph of larvae using Giemsa staining solution. Entomopathogenic fungi caused differential mortality on larvae: BB1, BB3, M. anisopliae lead to the highest mortality on larvae and L. lecanii caused the lowest mortality. The highest numbers of total hemocytes were observed 3 h post-injection of B. bassiana isolates and 6 h for the other treatments. The highest numbers of plasmatocytes were observed 3 h post-injection of BB1 and Tween 80, whereas BB2, BB3, M. anisopliae, I. fumosoroseus and L. lecani caused plasmatocyte increase 6 h post-injection. Similar results were obtained in case of granulocytes but only Tween 80 showed the highest number of hemocytes 3 h post-injection. The highest numbers of nodules were found at various time intervals after injection of fungal isolates and latex bead. The highest activities of phenoloxidase were observed 12 h post-injection by BbB1, BbB3, M. anisopliae and latex bead; 3-6 h post-injection by BbB2, 6 h post-injection by I. fumosoroseus and 3-6 h post-injection by L. lecanii. Our data demonstrate the possibility of utilizing different fungal extracts in the field to help reduce the risk of resistance evolution in C. suppressalis and encourage experimentations aimed to increase the number of biological control agent for insect pests such as the striped rice stem borer C. suppressalis. PMID:24447729

  17. Model for Unfolding Laundry using Interactive Perception Bryan Willimon, Stan Birchfield, and Ian Walker

    E-print Network

    ,stb}@clemson.edu, ianw@ces.clemson.edu Abstract-- We present an algorithm for automatically un- folding a piece, unfolding/flattening, folding, and putting it away into a predetermined drawer or storage unit. Figure 1] [9] [11] [12] [13] clothes. Folding, in particular, has received significant attention as of late [14

  18. Journeying as Religious Education: The Shaman, the Hero, the Pilgrim, and the Labyrinth Walker

    ERIC Educational Resources Information Center

    Senn, Corelyn F.

    2002-01-01

    In this article the author looks at the image of journey and its archeform, quest, and finds two spiritual concepts: that of movement to the center followed by a return, and the concomitant understanding that all that has arisen and reached maturity must return to renew itself. Four journeys, the shamanic journey of soul, the hero's journey of…

  19. Random walkers with extreme value memory: modelling the peak-end rule

    NASA Astrophysics Data System (ADS)

    Harris, Rosemary J.

    2015-05-01

    Motivated by the psychological literature on the ‘peak-end rule’ for remembered experience, we perform an analysis within a random walk framework of a discrete choice model where agents’ future choices depend on the peak memory of their past experiences. In particular, we use this approach to investigate whether increased noise/disruption always leads to more switching between decisions. Here extreme value theory illuminates different classes of dynamics indicating that the long-time behaviour is dependent on the scale used for reflection; this could have implications, for example, in questionnaire design.

  20. Farmers' perceptions of the white stem borer Scirpophaga innotata (Walker), in Cilamaya, West Java, Indonesia

    Microsoft Academic Search

    E. G. Rubia; A. A. Lazaro; K. L. Heong; Diah; Nurhasyim; G. A. Norton

    1996-01-01

    In connection with the white stem borer outbreak, reported during the 1989–1990 wet season in the northern part of West Java, field surveys were conducted to determine the importance of this pest to farmers, to assess their knowledge of it and to determine current control practices. The largest percentage (85%) of farmers perceived the white stem borer as important and

  1. Thad G. Walker Professor of Physics, University of Wisconsin-Madison

    E-print Network

    Walker, Thad G.

    in Atomic, Molecular, and Optical Physics; "Spin-Exchange Optical Pumping of Noble-Gas Nuclei", Reviews in spin exchange, op- tical pumping, ultracold collisions, spin polarized beams and targets, laser cooling-exchange optical pumping; Biomagnetometry; Laser cooling and trapping of atoms; Quantum computation with atoms

  2. Rb-Xe spin relaxation in dilute Xe mixtures I. A. Nelson and T. G. Walker

    E-print Network

    Walker, Thad G.

    s : 32.80.Bx The realization of magnetic resonance imaging of human subjects using hyperpolarized noble and the linewidth of inexpensive, high power but broadband diode laser sources requires pressure broadening the Rb reso- nance lines with many atmospheres of He gas, chosen for its weak spin-relaxation properties 6

  3. Mimicking Friedmann-Robinson-Walker universes with tunable cold Fermi atoms: Galilean invariance fights back

    E-print Network

    Lin, Chi-Yong; Rivers, Ray J

    2013-01-01

    In a series of papers to demonstrate emergent 'gravity' some authors have explored phonon production in BECs with a tunable speed of sound, in particular to emulate FRW universes. The premiss is that, within such systems, the gapless mode (the phonon) looks Lorentzian for low momentum at least. However, when it comes to phonon production in cold Fermi gases whose speed of sound is controlled by a Feshbach resonance, it is impossible to shake off the the underlying Galilean invariance because of the interplay between gapless and gapped modes. Such phonons as are produced do not follow the pattern anticipated for FRW metrics, at variance with the aims of the programme.

  4. Hybrid Geometric Feedback Control of Three-Dimensional Bipedal Robotic Walkers with Knees and Feet 

    E-print Network

    Sinnet, Ryan Wesley

    2012-07-16

    of hybrid systems for modeling purposes. The framework of hybrid systems was used to model three-dimensional bipedal walking in a general setup for a robotic model with a hip, knees, and feet with the goal of obtaining stable walking. To achieve three-dimensional...

  5. Stick-slip Actuation of Electrostatic Stepper Micropositioners for Data Storage - the µWalker

    Microsoft Academic Search

    Mihai Patrascu; Stefano Stramigioli

    2005-01-01

    This paper is about the µW alker, an electrostatic stepper motor mainly intended for positioning the data probes with respect to the storage medium in a data storage device. It can deliver forces up to 1.7mN for ranges as large as 140µm. Controlling the stick-slip ef- fects at the sliding surfaces is of central importance for reliable operation. A model

  6. Psychophysical Scaling of Sonification Mappings Bruce N. Walker Gregory Kramer David M. Lane

    E-print Network

    establish a mapping and polarity, what is the scaling factor for that data and display pair? That is on mappings, polarities, and scaling functions determined either by system constraints (e.g., only frequency, velocity? Second, what is the direction or "polarity" of the preferred data-to-display mappings

  7. Forest nutrient and carbon pools at Walker Branch Watershed: Changes during a 21-year period

    Microsoft Academic Search

    C. C. Trettin; D. W. Johnson; D. E. Jr. Todd

    1999-01-01

    A 21-yr perspective on changes in nutrient and C pools on undisturbed upland forest sites is provided. Plots originally representing four cover types have been sampled three times. On each plot, forest biomass, forest floor, and soil, to a depth of 60 cm, were measured, sampled, and analyzed for Ca, Mg, C, N, and P. Exchangeable soil Ca and Mg

  8. Spatial foraging in free ranging bearded sakis: traveling salesmen or Lévy Walkers?

    PubMed

    Shaffer, Christopher A

    2014-05-01

    According to optimal foraging theory and most current models of primate socioecology, primate foraging involves a series of decisions concerning when is the most optimal time to leave a food patch, how to travel to the next patch in an efficient manner, and how to minimize the time and distance traveled to all patches throughout the course of the day. In this study, I assess how bearded sakis solve these challenges by presenting data on their patch use, distance minimization, and by comparing their movements with non-deterministic foraging patterns. The study group, composed of 38?±?15 individuals, fed significantly longer in higher quality patches (quality defined by patch size and productivity) and in those that contained ripe fruit pulp. However, group size was not a significant predictor of patch occupancy. Bearded sakis traveled relatively directly between food patches, sometimes over distances >?300?m. In addition, they chose the optimal daily path among all patches visited on 9 of 17 occasions, and on average traveled only 21% more than the least distance route. Bearded saki step lengths were consistent with a Brownian rather than a Lévy Walk pattern while waiting times were consistent with a Lévy pattern. However, the distribution of their turning angles indicated a high degree of directional persistence between patches. These results suggest that bearded sakis exploit food patches that are randomly distributed spatially but heterogenous in patch quality. They appear to encode the locations of high quality food patches and minimize travel between them, despite opportunistically feeding from more abundant and randomly distributed, lower quality patches en route. PMID:24166852

  9. Functional Asymmetry in a Five-Link 3D Bipedal Walker

    PubMed Central

    Gregg, Robert D.; Dhaher, Yasin; Lynch, Kevin M.

    2014-01-01

    This paper uses a symmetrical five-link 3D biped model to computationally investigate the cause, function, and benefit of gait asymmetry. We show that for a range of mass distributions, this model has asymmetric walking patterns between the left and right legs, which is due to a phenomenon known as period-doubling bifurcation. The ground reaction forces of each leg reflect different roles, roughly corresponding to support, propulsion, and motion control as proposed by the hypothesis of functional asymmetry in human walking. These results suggest that natural mechanics could be responsible for asymmetry in able-bodied walking, rather than neurophysiological mechanisms such as leg dominance. PMID:22256152

  10. How to keep from falling forward: elementary swing leg action for passive dynamic walkers

    Microsoft Academic Search

    Martijn Wisse; Arend L. Schwab; Richard Quint van der Linde; Frans C. T. van der Helm

    2005-01-01

    Stability control for walking bipeds has been considered a complex task. Even two-dimensional fore-aft stability in dynamic walking appears to be difficult to achieve. In this paper we prove the contrary, starting from the basic belief that in nature stability control must be the sum of a number of very simple rules. We study the global stability of the simplest

  11. Classification of Clothing using Interactive Perception Bryan Willimon, Stan Birchfield, and Ian Walker

    E-print Network

    Classification of Clothing using Interactive Perception Bryan Willimon, Stan Birchfield, and Ian upon silhouettes, edges, and other low-level image measurements of the articles of clothing. The contributions of this paper are a novel method for extracting articles of clothing from a pile of laundry

  12. Reunion Probability of N Vicious Walkers: Typical and Large Fluctuations for Large N

    NASA Astrophysics Data System (ADS)

    Schehr, Grégory; Majumdar, Satya N.; Comtet, Alain; Forrester, Peter J.

    2013-02-01

    We consider three different models of N non-intersecting Brownian motions on a line segment [0, L] with absorbing (model A), periodic (model B) and reflecting (model C) boundary conditions. In these three cases we study a properly normalized reunion probability, which, in model A, can also be interpreted as the maximal height of N non-intersecting Brownian excursions (called "watermelons" with a wall) on the unit time interval. We provide a detailed derivation of the exact formula for these reunion probabilities for finite N using a Fermionic path integral technique. We then analyze the asymptotic behavior of this reunion probability for large N using two complementary techniques: (i) a saddle point analysis of the underlying Coulomb gas and (ii) orthogonal polynomial method. These two methods are complementary in the sense that they work in two different regimes, respectively for L? O(sqrt{N}) and L? O(sqrt{N}). A striking feature of the large N limit of the reunion probability in the three models is that it exhibits a third-order phase transition when the system size L crosses a critical value L=Lc(N)˜sqrt{N}. This transition is akin to the Douglas-Kazakov transition in two-dimensional continuum Yang-Mills theory. While the central part of the reunion probability, for L˜ L c ( N), is described in terms of the Tracy-Widom distributions (associated to GOE and GUE depending on the model), the emphasis of the present study is on the large deviations of these reunion probabilities, both in the right [ L? L c ( N)] and the left [ L? L c ( N)] tails. In particular, for model B, we find that the matching between the different regimes corresponding to typical L˜ L c ( N) and atypical fluctuations in the right tail L? L c ( N) is rather unconventional, compared to the usual behavior found for the distribution of the largest eigenvalue of GUE random matrices. This paper is an extended version of (Schehr et al. in Phys. Rev. Lett. 101:150601, 2008) and (Forrester et al. in Nucl. Phys. B 844:500-526, 2011).

  13. October 5, 2006 Dear Mark Walker, Director of Public Affairs, NPCC

    E-print Network

    ) in the Columbia and Wenatchee basins. The Wenatchee is one of three (BPA funded) intensively monitored watersheds Review Panel (ISRP) and Upper Columbia Salmon Recovery Board (UCSRB) reviews. During 2003, we initiated salmon in the Wenatchee River. The Northwest Power and Conservation Council, in its draft funding

  14. Magnetic models of unexploded ordnance Stephen D. Billings, Catherine Pasion, Sean Walker and Laurens Beran

    E-print Network

    Oldenburg, Douglas W.

    ,these orientation dependent detection depths ranged from 10 to 17 times the object's diameter. Index Terms were obtained by varying the 3-D orientation of each item and measuring the magnetic field (UXO) contamination is a significant, world-wide problem that prevents productive use of affected areas

  15. www.reading.ac.uk/meteoroloy www.walker-institute.ac.uk sbvbavpbafevjbafv

    E-print Network

    Hogan, Robin

    to improve understanding of our future climate and its impacts for the benefit of society. Teachers Sheet quicker than the air over the sea during the daytime. A density current forms as the cold (denser) sea air meets the warm land air. · Cold air outflows from thunderstorms ­ cold air in thunderstorm downdrafts

  16. An unusual combination: Aortic arch coarctation associated with Dandy–Walker variant

    Microsoft Academic Search

    Ahmet Akgul; Seyhan Babaroglu; Ilknur Bahar; Isik Bokesoy; Levent Birincio?lu; Adnan Cobanoglu

    2006-01-01

    We report on a 29-year-old woman with aortic arch coarctation with cerebral anomalies including posterior fossa cyst, hydrocephalus, cerebellar vermis hypoplasia and multiple congenital anomalies including hirsutism, hipotelorism, shortened philtrum, unregulated teeth and short alveolar crest, rotated auricles, short and webbed neck, hypopigmentation on the scalp, bilateral clinodactyly, bilateral hallux valgus, brachydactyly on the left foot 3rd finger, hemangioma on

  17. Accepted by G.Walker-Smith: 10 Jul 2006; published: 31 Jul. 2006 1 ISSN 1175-5326 (print edition)

    E-print Network

    Ivanenko, Viatcheslav N.

    , but differs from them in having two, instead of three, outer spines on the distal exopodal segment of leg 4 and Rimipontius mediospinifer Humes, 1996 known from three sites (Logachev, Snake Pit, and Broken Spur at 29°N-Atlantic Ridge hydrothermal vent fields TAG (26°N), Snake Pit, Broken Spur (29°N), and from the Mariana Back

  18. Dire le rel. Let Us Now Praise Famous Men de James Agee et Walker Evans , comme exprience de la reprsentation

    E-print Network

    Paris-Sud XI, Université de

    reposait le mythe démocratique des fondateurs au profit d'une société industrielle et urbaine. Le magazine Fortune, comme d'autres revues destinées à des lecteurs aisés et souvent influents, s'intéresse aux'Amérique, à se répéter. En avril 1936 les rédacteurs de Fortune souhaitent donc publier un article illustré de

  19. Activating the DNA damage checkpoint in a developmental context Tin Tin Su, Jeff Walker and Jason Stumpff

    E-print Network

    Su, Tin Tin

    into mitosis. Gastrulation and the developmental program of string (Cdc25) gene expression, which normally regulates the timing of mitosis, occurred normally after irradiation. The radiation-induced delay of mitosis and overcame the delay of mitosis induced by irradiation. Conclusions: Developmental changes in the cell cycle

  20. "Soft" Continuum Robots: the Interaction of Continuous and Discrete Elements Lara S. Cowan and Ian D. Walker

    E-print Network

    "Soft" Continuum Robots: the Interaction of Continuous and Discrete Elements Lara S. Cowan and Ian, USA Abstract In this paper, we examine key issues underlying the design and operation of soft robots featuring continuous body (continuum) elements. We contrast continuum and continuum-like robots created

  1. Space-time curvature and the cosmic horizon: derivations using the Newtonian world and the Friedmann-Robertson-Walker metric

    NASA Astrophysics Data System (ADS)

    Özta?, A. M.; Smith, M. L.

    2015-05-01

    Several relationships describing the distance versus time dependence of the cosmic horizon (Rh) for an expanding universe have been published within the past two decades. Some are based on the special conditions, including a flat universe geometry, and when applied for calculation return significantly different values. We present our derivation beginning with Newtonian world then following the Friedmann model from the viewpoint of an observer located at the origin of an expanding spherical, homogeneously matter-dominated universe; both geometrically flat and allowing space-time curvature. Our derivations for the cosmic horizon at the speed of light allow examination for the effects of matter density and space-time curvature. We also compare the fitness of several current models, including the recently proposed Rh = ct universe against the demands of the 580 Union 2.1 Type Ia supernovae distance and redshift data with uncommon, proper attention paid to data transformation and observational errors.

  2. Dual-task effects of spontaneous speech and executive function on gait in aging: Exaggerated effects in slow walkers

    Microsoft Academic Search

    Prudence Plummer-D’Amato; Lori J. P. Altmann; Kevin Reilly

    2011-01-01

    This study compared the effects of spontaneous speech and executive function on gait and investigated the effects of single-task gait speed on dual-task costs. Twenty-one older adults (74.7years, SD 5.9) and 23 younger adults (22years, SD 1.2) walked for 60s while performing an auditory Stroop task and a spontaneous speech task; they also performed each task in isolation. Walking while

  3. Determination of foraminiferal criteria for environmental interpretation using Upper Cretaceous sandstones, Brazos, Frio, Walker, and Zavala counties, Texas

    E-print Network

    Nufer, Janet Ann

    1979-01-01

    Bigfoot Field, Frio County, and one San Miguel sandstone core, Zavala County, represent a range of environments from inner to outer shelf. Two Upper Cretaceous Wood- bine sandstone and shale cores from Kurten field, Brazos County, and from a wildcat...) ~ . . . ~ . . . . . . 44 Bathymetric zonation of trace fossil com- munities (Sei lacher, 1967, p. 418). . . . 50 10 Sedimentary structures in Olmos sandstones, Glenn & Associates Gracy 1 (A-E), Glenn & Associates Howard 1 (F, G), West Bigfoot Field, Frio County, Texas...

  4. 11. PUBLICATIONS 2001-2002 Addis Tsehaye, Buchanan, A.H. & Walker, J.C.F. Selecting trees for structural

    E-print Network

    Hickman, Mark

    indigenous forestry sector is in the national interest. NZ Journal of Forestry 46(1) 2001: 22-26pp Devoe, N using acoustics. Journal of Wood Science & Technology 34(4) 2000: 337-44pp Albert, D.J., Clark, T

  5. Development of leg chordotonal sensory organs in normal and heat shocked embryos of the cricket Teleogryllus commodus (Walker)

    Microsoft Academic Search

    Monika Klose

    1996-01-01

    This paper describes the embryonic development of some parts of the sensory peripheral nervous system in the leg anlagen of the cricket Teleogryllus commodus in normal and heat shocked embryos. The first peripheral neurons appear at the 30% stage of embryogenesis. These tibial pioneer neurons grow on a stereotyped path to the central nervous system and form a nerve which

  6. Skew light propagation in optically thick optical pumping cells B. Chann, E. Babcock, L. W. Anderson, and T. G. Walker

    E-print Network

    Walker, Thad G.

    -exchange optical pumping 1 , it is common that optically very thick alkali-metal atom samples are optically pumped with high-power laser sources such as broadband diode laser arrays 2 , frequency nar- rowed diode arrays, and diode-array bars 3­5 or Ti:Sap- phire lasers 6,7 . As circularly polarized light propagates through

  7. 3D Pose Tracking of Walker Users' Lower Limb with a Structured-Light Camera on a Moving Platform

    E-print Network

    Poupart, Pascal

    hospitalization among seniors. In addition to phys- ical consequences (e.g. hip fracture, loss of mobility), falls and variability), which lack reliable spatial estimates (e.g. step length and width). Temporal and spatial mea

  8. Determination of foraminiferal criteria for environmental interpretation using Upper Cretaceous sandstones, Brazos, Frio, Walker, and Zavala counties, Texas 

    E-print Network

    Nufer, Janet Ann

    1979-01-01

    lo hra moides and Robulus. The tests of both genera are strongly resistant to mechanical abra- sion caused by wave and current action. 3) The planktonic:benthonic ratio is a useful criterion for environment interpretation. The propor- tion... Criteria - Taphonomy Validity of Analogies between Fossil and Modern Foraminiferal Assemblages Abundance, Diversity and Faunal Dominanc Planktonic:Benthonic Ratio Arenaceous:Hyaline:Porcelaneous Ratio ~ DEPOSITIONAL INTERPRETATIONS OF THE OLNOS, SAN...

  9. ProstateAnalyzer: GUI in Medical Domain with Management of DICOM Images of Prostate Cancer (PCa) , P.M. Walker

    E-print Network

    Paris-Sud XI, Université de

    ProstateAnalyzer: GUI in Medical Domain with Management of DICOM Images of Prostate Cancer (PCa) C is an improved create/recover/update prostate diagnosis provided by different experts. It is an efficient way visualization and analysis for MR imaging of the prostate and a new storage system of clinical diagnoses

  10. Dog walkers’ vs. other park visitors’ perceptions: The importance of planning sustainable urban parks in Bucharest, Romania

    Microsoft Academic Search

    Cristian I. Ioj?; Lauren?iu Rozylowicz; Maria P?troescu; Mihai R. Ni??; Gabriel O. Vânau

    2011-01-01

    Society consumption models have changed significantly and are now oriented towards fulfilling stronger sustainability requirements and following the demand for better living standards. In this respect, companion animals are a common presence in households in large urban areas. The number of companion animals is increasing in Bucharest (38.7 animals per 100 households). This tendency has caused notable changes in urban

  11. June'2001 Journal of Vector Ecology 1740^0 103 Habitat preference of host-seeking Coquillettidia perturbans (Walker) in

    E-print Network

    in Ocean County, New Jersey. We first examined the abundance of host-seeking Cq. perturbans at a height of 1.0 m in each ofthree habitats: forest, open field and marsh We collected significantly more mosquitoes in the forest as compared to the marsh. Forest and field collections did not differ significantly

  12. ROBERT WALKER DIED ON February 12, 2004, in Brussels, Belgium, after an extended battle with stomach cancer.

    E-print Network

    for the rest of his life as his real father. During the Great Depression, when there were few jobs, the three on the farm during the Depression was chal- lenging. He had to walk a mile, sometimes in blizzard conditions Asian and 50 percent girls. Bob learned that he could excel at science in a dog-eat-dog environment

  13. The Fisher Corpus: a Resource for the Next Generations of Speech-to-Text Christopher Cieri, David Miller, Kevin Walker

    E-print Network

    Pennsylvania, University of

    . Fisher data is already in use within the DARPA EARS programs and will be published via the Linguistic among the problems addressed by the DARPA EARS program is the accuracy of conversational ASR systems {ccieri,damiller,walkerk}@ldc.upenn.edu Abstract This paper describes, within the context of the DARPA

  14. NOMENCLATURAL CHANGES IN THE FAMILY PTEROMALIDAE, WITH DESCRIPTION OF THE FIRST NEW WORLD SPECIES OF ORMOCERUS WALKER (HYMENOPTERA, CHALCIDOIDEA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The new species Ormocerus americanus Dzhanokmen and Grissell is described based on specimens reared from cynipid galls on oak in Texas. The following new synonymies are proposed: Abyrsomele Dzhanokmen 1975 = Halticopterina Erdös 1946; Halticopterina penthocoryne Dzhanokmen 1975 = H. moczari Erdös 19...

  15. r. Walker arrives at the high-security research facility where he works, eager to see the results of

    E-print Network

    Plataniotis, Konstantinos N.

    synthesized, voice. Although today there is no practical system that can support the above authentication scenario, the latest research on gait-based identification--identification by observation of a person in the years to come. The study of human gait, as well as its deployment as a biometric for identification pur

  16. Elhamma Walker (Lepidoptera: Hepialidae) revisited: adult morphology, assessment of recently proposed synonyms and descriptions of two species.

    PubMed

    Simonsen, Thomas J

    2015-01-01

    I revise the Australian-New Guinean ghost moth genus Elhamma. Two recent synonymies are assessed, and two new species from New Guinea, E. grehani sp. nov. and E. viettei sp. nov. are described. I provide an updated diagnosis for the genus and conclude that the presence of only 2 M-veins in the hind wing in both sexes (when females are known) and a strongly cup-shape juxta in the male genitalia are unique diagnostic characters among Hepialidae. I give a detailed description of the adult morphology based on male E. australasiae, and provide a key to all known species based on adult male characters. PMID:25947855

  17. PTC-6 vacuum system: WallWalker{trademark} and Blastrac{reg_sign} shot blast cleaning system

    SciTech Connect

    NONE

    1998-02-01

    The LTC Americas, Inc. wall decontamination technology consisted of two pneumatic hand-held tools: (1) a roto-peen scaler that used star cutters and (2) a 3-piston hammer with reciprocating bits. The hand-held tools were used in conjunction with the LTC PTC-6 vacuum system which captured dust and debris as the wall decontamination took place. Recommendations for improved worker safety and health during use of the PTC-6 vacuum system with hand-held tools include: (1) keeping all hoses and lines as orderly as possible in compliance with good housekeeping requirements; (2) ergonomic training to include techniques in lifting, bending, stooping, twisting, etc.; (3) use of a clamping system to hold hoses to the vacuum system; (4) a safety line on the air line connections; (5) use of a mechanical lifting system for waste drum removal; and (6) the use of ergonomically designed tools.

  18. Constituents of wing gland and abdominal hair pencil secretions of male African sugarcane borer, Eldana saccharina walker (Lepidoptera: Pyralidae)

    Microsoft Academic Search

    B. V. Burger; A. E. Nell; D. Smit; H. S. C. Spies; W. M. Mackenroth; D. Groche; P. R. Atkinson

    1993-01-01

    In addition totrans-3,7-dimethyl-6-octen-4-olide (eldanolide), vanillin, and 4-hydroxybenzaldehyde, identified by French workers in the wing gland and abdominal hair pencil secretions of the male African sugarcane borer,Eldana saccharina, we have, in an earlier note, reported the presence of several other terpenoid, aromatic, and unbranched-chain compounds such as, (Z)-3,7-dimethylocta-2,6-dienoic acid, 6,10,14-trimethyl-2-pentadecanol, 4-hydroxy-3-methoxybenzyl alcohol, 1-octadecane thiol, 16-hexadecanolide, and 18-octadecanolide in these secretions. In

  19. Host Plants Affect the Foraging Success of Two Parasitoids that Attack Light Brown Apple Moth Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae).

    PubMed

    Feng, Yi; Wratten, Steve; Sandhu, Harpinder; Keller, Michael

    2015-01-01

    The light brown apple moth, Epiphyas postvittana is a key pest of wine grapes in Australia. Two parasitoids, Dolichogenidea tasmanica and Therophilus unimaculatus, attack the larval stage of this pest. D. tasmanica is dominant in vineyards, whereas T. unimaculatus is mainly active in native vegetation. We sought to understand why they differ in their use of habitats. Plants are a major component of habitats of parasitoids, and herbivore-infested plants influence parasitoid foraging efficiency by their architecture and emission of volatile chemicals. We investigated how different plant species infested by E. postvittana could affect the foraging success of the two parasitoid species in both laboratory and field experiments. Four common host-plant species were selected for this study. In paired-choice experiments to determine the innate foraging preferences for plants, both parasitoid species showed differences in innate search preferences among plant species. The plant preference of D. tasmanica was altered by oviposition experience with hosts that were feeding on other plant species. In a behavioral assay, the two parasitoid species allocated their times engaged in various types of behavior differently when foraging on different plant species. For both parasitoids, parasitism on Hardenbergia violacea was the highest of the four plant species. Significantly more larvae dropped from Myoporum insulare when attacked than from the other three host-plant species, which indicates that parasitism is also affected by interactions between plants and host insects. In vineyards, parasitism by D. tasmanica was significantly lower on M. insulare than on the other three host-plant species, but the parasitism rates were similar among the other three plant species. Our results indicate that plants play a role in the habitat preferences of these two parasitoid species by influencing their foraging behavior, and are likely to contribute to their distributions among habitats. PMID:25893966

  20. December Safety Meeting Minutes Members Present: Lori Parker (ODF&W) Randy Walker (HMSC) Alana Preble (HMSC)

    E-print Network

    of the road in front of ODF&W being free from water during the November flooding of 06. This was the result about HMSC Facilities adopting a "Best Management Practice" for storm water runoff in the parking lots