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1

Host specificity in the host-seeking larva of the dipteran parasitoid Mallophora ruficauda and the influence of age on parasitism decisions.  

PubMed

Larvae of the robber fly Mallophora ruficauda are ectoparasitoids of white grubs and adults are an important apiculture pest in Argentina. Females oviposit on tall grasses and the second instar larva actively searches and locates hosts. There are nine potential hosts in the distribution area of this parasitoid and Cyclocephala signaticollis (Coleoptera: Scarabaeidae) is the most parasitized in the field. However, M. ruficauda has a certain degree of behavioural flexibility towards different host species, and not being a strict specialist. The conditions under which the parasitoid orientates and accepts different hosts' species are unknown. We studied the host specificity of M. ruficauda towards three species of Cyclocephala genus and we determined whether this specificity depends on larval age. We also evaluated whether larva orientation towards Cyclocephala species changes with chemical cue concentration. We assessed host specificity measuring the orientation and acceptance behaviours towards kairomones extracts and live individuals of Cyclocephala species using M. ruficauda larvae of low and high life expectancy (i.e., young and aged second instar larvae). We observed that young larvae orientated only towards C. signaticollis chemical stimulus, whereas aged larvae orientated also towards C. modesta, and the same was observed with increasing stimuli's concentration. Both young and aged M. ruficauda larvae orientate towards live C. signaticollis and C. putrida species and rejected C. modesta. Also, we found that larvae accepted all Cyclocephala hosts. In conclusion, our results indicate that specificity in the laboratory, observed through host orientation and host acceptance behaviours, depends not only on the availability of host species, but also on the nature of the host's stimuli combined with parasitoid age. PMID:24548616

Barrantes, M E; Castelo, M K

2014-06-01

2

Walker's Eleodes (Coleoptera: Tenebrionidae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The type specimens of five species of Eleodes described by Francis Walker were studied in order to establish their true identity. The synonymy of Eleodes convexicollis Walker and Eleodes conjunctus Walker with E. obscurus (Say); that of Eleodes latiusculus Walker with E. humeralis LeConte; and that ...

3

Dandy-Walker Syndrome  

MedlinePLUS

... en Español Síndrome de Dandy-Walker Prepared by: Office of Communications and Public Liaison National Institute of Neurological Disorders and Stroke National Institutes of Health Bethesda, MD 20892 NINDS health-related material is provided for information purposes only and does ...

4

Asymmetric passive dynamic walker.  

PubMed

The objective of this research is to better understand the dynamics of gait asymmetry in humans with central nervous system damage, such as stroke, by using a model of a passive dynamic walker (PDW). By changing the mass, mass location, knee location, and leg length of one leg while leaving the parameters of the other leg unchanged, we show that stable asymmetric walking patterns exist for PDW models. The asymmetric PDW model shows several stable walking patterns that have a single, double, and quadruple repeat pattern where the step lengths between the two legs differ by over 15%. This model will allow an analysis of the passive dynamics of walking separate from the cognitive control in asymmetric human walking to test different gait rehabilitation hypotheses. PMID:22275663

Honeycutt, Craig; Sushko, John; Reed, Kyle B

2011-01-01

5

Simple autonomous Mars walker  

NASA Technical Reports Server (NTRS)

Under a contract with NASA's Jet Propulsion Laboratory, Martin Marietta has developed several alternative rover concepts for unmanned exploration of the planet Mars. One of those concepts, the 'Walking Beam', is the subject of this paper. This concept was developed with the goal of achieving many of the capabilities of more sophisticated articulated-leg walkers with a much simpler, more robust, less computationally demanding and more power efficient design. It consists of two large-base tripods nested one within the other which alternately translate with respect to each other along a 5-meter beam to propel the vehicle. The semiautonomous navigation system relies on terrain geometry sensors and tacticle feedback from each foot to autonomously select a path which avoids hazards along a route designated from earth. Both mobility and navigation features of this concept are discussed including a top-level description of the vehicle's physical characteristics, deployment strategy, mobility elements, sensor suite, theory of operation, navigation and control processes, and estimated performance.

Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.

1989-01-01

6

Intelligently Controllable Walker with Magnetorheological Fluid Brake  

NASA Astrophysics Data System (ADS)

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.

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

7

The Albany Medical College Ventilator Walker.  

PubMed

This report describes the design and use of a wheeled walker that can accommodate a ventilator and oxygen tanks. It is constructed of aluminum tubing. The front of the walker has receptacles to support a Mark 7 Bird Ventilator and oxygen tanks. The back end of the walker has a bench seat that is lifted to allow entry into the walker. The seat provides rigidity and stability to the frame of the walker. The walker has been used in the Medical Intensive Care Unit of the Albany Medical Center to facilitate early ambulation of patients who are ventilator dependent or who require a portable source of oxygen to begin ambulation training. PMID:8976320

Smith, T; Forrest, G; Evans, G; Johnson, R K; Chandler, N

1996-12-01

8

21 CFR 890.3825 - Mechanical walker.  

Code of Federal Regulations, 2010 CFR

...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 walker is a four-legged...

2010-04-01

9

21 CFR 890.3825 - Mechanical walker.  

Code of Federal Regulations, 2013 CFR

...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 walker is a four-legged...

2013-04-01

10

July 13, 2007 Mark Walker  

E-print Network

involved with Northwest electric system planning and the design and implementation of energy efficiency of the fact that energy efficiency programs planned and implemented under the Council's guidance for the last at the Northwest Power and Conservation Planning Assumptions, Council Document 2007-7 Dear Mr. Walker: On behalf

11

Abstract models of molecular walkers  

NASA Astrophysics Data System (ADS)

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.

Semenov, Oleg

12

LETTER: Walkers on the circle  

NASA Astrophysics Data System (ADS)

We demonstrate experimentally that the statistical properties of distances between pedestrians which are hindered from avoiding each other are described by the Gaussian unitary ensemble of random matrices. The same result has recently been obtained for an n-tuple of non-intersecting (one-dimensional, unidirectional) random walks. Thus, the observed behavior of autonomous walkers conditioned not to cross their trajectories (or, in other words, to stay in strict order at any time) resembles non-intersecting random walks.

Jezbera, Daniel; Kordek, David; K?íž, Jan; Šeba, Petr; Šroll, Petr

2010-01-01

13

21 CFR 890.3825 - Mechanical walker.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

14

Walker Branch Watershed Ecosystems Data  

DOE Data Explorer

These projects have all contributed to a more complete understanding of how forest watersheds function and have provided insights into the solution of energy-related problems associated with air pollution, contaminant transport, and forest nutrient dynamics. This is one of a few sites in the world characterized by long-term, intensive environmental studies. The Walker Branch Watershed website at http://walkerbranch.ornl.gov/ provides maps, photographs, and data on climate, precipitation, atmospheric deposition, stream discharge and runoff, stream chemistry, and vegetation. [Taken from http://walkerbranch.ornl.gov/ABOUTAAA.HTM

15

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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...

2013-08-08

16

by John Walker The Hacker's Diet  

E-print Network

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

Bernstein, Daniel

17

undergraduate programs walker college of business  

E-print Network

undergraduate and graduate majors. Small classes and close interactions between faculty and students create pass rate and award-winning faculty, the college is one of the best in the nation at helping studentsundergraduate programs #12;walker college of business Walker College of Business Today's global

Thaxton, Christopher S.

18

Oceanic Regulation of the Atmospheric Walker Circulation  

Microsoft Academic Search

A coupled theory is proposed to account for the magnitude of the Walker circulation in the tropical Pacific. It is suggested that the Pacific Walker circulation is at a saturation state, at which the zonal sea surface temperature difference is bounded by about a quarter of the latitudinal difference of the radiative-convective equilibrium sea surface temperature.

Zhengyu Liu

1997-01-01

19

FellWalker-A clump identification algorithm  

NASA Astrophysics Data System (ADS)

This paper describes the FellWalker algorithm, a watershed algorithm that segments a 1-, 2- or 3-dimensional array of data values into a set of disjoint clumps of emission, each containing a single significant peak. Pixels below a nominated constant data level are assumed to be background pixels and are not assigned to any clump. FellWalker is thus equivalent in purpose to the CLUMPFIND algorithm. However, unlike CLUMPFIND, which segments the array on the basis of a set of evenly-spaced contours and thus uses only a small fraction of the available data values, the FellWalker algorithm is based on a gradient-tracing scheme which uses all available data values. Comparisons of CLUMPFIND and FellWalker using a crowded field of artificial Gaussian clumps, all of equal peak value and width, suggest that the results produced by FellWalker are less dependent on specific parameter settings than are those of CLUMPFIND.

Berry, D. S.

2015-04-01

20

Averaging Robertson-Walker cosmologies  

SciTech Connect

The cosmological backreaction arises when one directly averages the Einstein equations to recover an effective Robertson-Walker cosmology, rather than assuming a background a priori. While usually discussed in the context of dark energy, strictly speaking any cosmological model should be recovered from such a procedure. We apply the scalar spatial averaging formalism for the first time to linear Robertson-Walker universes containing matter, radiation and dark energy. The formalism employed is general and incorporates systems of multiple fluids with ease, allowing us to consider quantitatively the universe from deep radiation domination up to the present day in a natural, unified manner. Employing modified Boltzmann codes we evaluate numerically the discrepancies between the assumed and the averaged behaviour arising from the quadratic terms, finding the largest deviations for an Einstein-de Sitter universe, increasing rapidly with Hubble rate to a 0.01% effect for h = 0.701. For the {Lambda}CDM concordance model, the backreaction is of the order of {Omega}{sub eff}{sup 0} Almost-Equal-To 4 Multiplication-Sign 10{sup -6}, with those for dark energy models being within a factor of two or three. The impacts at recombination are of the order of 10{sup -8} and those in deep radiation domination asymptote to a constant value. While the effective equations of state of the backreactions in Einstein-de Sitter, concordance and quintessence models are generally dust-like, a backreaction with an equation of state w{sub eff} < -1/3 can be found for strongly phantom models.

Brown, Iain A.; Robbers, Georg [Institut fuer Theoretische Physik, Philosophenweg 16, 69120 Heidelberg (Germany)] [Institut fuer Theoretische Physik, Philosophenweg 16, 69120 Heidelberg (Germany); Behrend, Juliane, E-mail: I.Brown@thphys.uni-heidelberg.de, E-mail: G.Robbers@thphys.uni-heidelberg.de, E-mail: Juliane.Behrend@uni-ulm.de [Institut fuer Theoretische Physik, Albert-Einstein-Allee 11, 89069 Ulm (Germany)] [Institut fuer Theoretische Physik, Albert-Einstein-Allee 11, 89069 Ulm (Germany)

2009-04-15

21

The instrumented walker: usage patterns and forces.  

PubMed

Studies documenting the forces that are transmitted through a walker's frame are still scant. The purpose of this study was to evaluate the pattern and magnitude of forces that are transmitted through the frame of a walker during ambulation. A standard aluminum walker was instrumented. Gauges, which were mounted on all four legs, recorded axial, frontal, and sagittally oriented forces. A custom made computerized system registered the forces during 30 seconds of data acquisition. Twelve patients with ambulation dysfunction were tested with this system. Two different usage patterns emerged from the study. One usage pattern was observed in patients who were using the walker as a mean to reduce the amount of weight transmitted through the lower extremity. The second pattern was observed in patients with severe balance problems. These patients used the walker to enhance their balance and stability. The system described allows walker usage pattern analysis. Better understanding of force distribution and usage patterns may lead to improved or new walker design. PMID:7741624

Fast, A; Wang, F S; Adrezin, R S; Cordaro, M A; Ramis, J; Sosner, J

1995-05-01

22

X-1A with pilot Joe Walker  

NASA Technical Reports Server (NTRS)

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.

1955-01-01

23

Empirical Studies in Discourse Marilyn A. Walker  

E-print Network

under investigation (Cohen, 1995; Sparck-Jones and Galliers, 1996; Walker, 1996).1 The role of empirical Sparck-Jones and Galliers (1996, p.23) call features performance factors and distinguish between

Moore, Johanna D.

24

Exploration and trapping of mortal random walkers.  

PubMed

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. PMID:23767708

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

2013-05-31

25

Exploration and Trapping of Mortal Random Walkers  

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

26

Active faulting in the Walker Lane  

NASA Astrophysics Data System (ADS)

Deformation across the San Andreas and Walker Lane fault systems accounts for most relative Pacific-North American transform plate motion. The Walker Lane is composed of discontinuous sets of right-slip faults that are located to the east and strike approximately parallel to the San Andreas fault system. Mapping of active faults in the central Walker Lane shows that right-lateral shear is locally accommodated by rotation of crustal blocks bounded by steep-dipping east striking left-slip faults. The left slip and clockwise rotation of crustal blocks bounded by the east striking faults has produced major basins in the area, including Rattlesnake and Garfield flats; Teels, Columbus and Rhodes salt marshes; and Queen Valley. The Benton Springs and Petrified Springs faults are the major northwest striking structures currently accommodating transform motion in the central Walker Lane. Right-lateral offsets of late Pleistocene surfaces along the two faults point to slip rates of at least 1 mm/yr. The northern limit of northwest trending strike-slip faults in the central Walker Lane is abrupt and reflects transfer of strike-slip to dip-slip deformation in the western Basin and Range and transformation of right slip into rotation of crustal blocks to the north. The transfer of strike slip in the central Walker Lane to dip slip in the western Basin and Range correlates to a northward broadening of the modern strain field suggested by geodesy and appears to be a long-lived feature of the deformation field. The complexity of faulting and apparent rotation of crustal blocks within the Walker Lane is consistent with the concept of a partially detached and elastic-brittle crust that is being transported on a continuously deforming layer below. The regional pattern of faulting within the Walker Lane is more complex than observed along the San Andreas fault system to the west. The difference is attributed to the relatively less cumulative slip that has occurred across the Walker Lane and that oblique components of displacement are of opposite sense along the Walker Lane (extension) and San Andreas (contraction), respectively. Despite the gross differences in fault pattern, the Walker Lane and San Andreas also share similarities in deformation style, including clockwise rotations of crustal blocks leading to development of structural basins and the partitioning of oblique components of slip onto subparallel strike-slip and dip-slip faults.

Wesnousky, Steven G.

2005-06-01

27

The Walker Lane in northeastern California  

SciTech Connect

The Walker Lane (Locke and others, 1940) was defined as a narrow northwest-trending dextral fault zone that separates basin- and range topography on the east from diverse topography on the west that extends discontinuously from Lake Mead to Honey Lake. The term Walker Lane Belt (Steward, 1988) expands the feature to include a wide zone east of the Sierra Nevada. Pease (1969), Hannah (1977), and Grose (1986) suggested that the tectonic characteristics of Walker Lane continue into the Modoc Plateau. The authors believe that it is useful to recognize the Walker Lane or Walker Lane Belt in the Modoc Plateau. Within the Modoc Plateau, a 25-km wide (15-mile wide) zone of northwest-southeast faults herein recognized as the Walker Lane, trends N35{degree}W from Honey Lake Basin to Medicine Lake Highland. Mapping in the Eagle Lake area revealed northwest-southeast, north-south, and northeast-southwest late Quaternary faults and rifts, eruptive fissures, small tectonic depressions, and the large Eagle Lake volcano-tectonic depression. To the east is a remarkably unfaulted Neogene volcanic terrane extending 70 km (42 miles) eastward to the Dry Valley-Smoke Creek Desert fault system in Nevada. To the west in the Cascades complex late Pliocene-Quaternary faulting, linear basaltic cones, and andesite volcanoes are all aligned N15{degree}-30{degree}W. This Modoc part of the Walker Lane Belt displays blocks tilted mostly 3{degree}-10{degree}E bounded by west-dipping normal faults and right diagonal normal faults. Left stepping north-south trending rifts occur within northwest trending, straight right diagonal-slip fault zones.

Saucedo, G.J.; Wagner, D.L.; Grose, T.L.T.

1990-01-01

28

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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...

2013-04-30

29

75 FR 35265 - Safety Standard for Infant Walkers: Final Rule  

Federal Register 2010, 2011, 2012, 2013, 2014

...Operations, Directorate for Engineering Sciences, Consumer Product...United States, including China, the United Kingdom, and...ASTM standard dramatically affected incidents related to walkers...failure, either structural or mechanical failure of the walker,...

2010-06-21

30

Dual position locking joint design for a medical walker  

E-print Network

In this thesis we analyzed a joint created for a medical walker currently in the prototyping stage of development. The walker is designed to help a user stand up from a seated position. The joint holds two legs of the ...

Beecher, Eric M

2010-01-01

31

Attitudes to and use of baby walkers in Dublin  

Microsoft Academic Search

OBJECTIVES: To identify the rate of baby walker use, parental attitudes, and associated injuries. DESIGN: Parents of babies attending clinics for developmental assessment were surveyed by self administered questionnaire about their use, attitudes, and history of injuries associated with walkers. SETTING: Dublin, Ireland. SUBJECTS: Parents of 158 babies. RESULTS: Fifty five per cent of the sample used a walker. The

M. Laffoy; P. Fitzpatrick; M. Jordan; D. Dowdall

1995-01-01

32

Soils of Walker Branch Watershed  

SciTech Connect

The soil survey of Walker Branch Watershed (WBW) utilized the most up-to-date knowledge of soils, geology, and geohydrology in building the soils data base needed to reinterpret past research and to begin new research in the watershed. The soils of WBW were also compared with soils mapped elsewhere along Chestnut Ridge on the Oak Ridge Reservation to (1) establish whether knowledge obtained elsewhere could be used within the watershed, (2) determine whether there were any soils restricted to the watershed, and (3) evaluate geologic formation lateral variability. Soils, surficial geology, and geomorphology were mapped at a scale of 1:1200 using a paper base map having 2-ft contour intervals. Most of the contours seemed to reasonably represent actual landform configurations, except for dense wooded areas. For example, the very large dolines or sinkholes were shown on the contour base map, but numerous smaller ones were not. In addition, small drainageways and gullies were often not shown. These often small but important features were located approximately as soil mapping progressed. WBW is underlain by dolostones of the Knox Group, but only a very small part of the surface area contains outcroppings of rock and most outcrops were located in the lower part. Soil mapping revealed the presence of both ancient alluvium and ancient colluvium deposits, not recognized in previous soil surveys, that have been preserved in high-elevation stable portions of present-day landforms. An erosional geomorphic process of topographic inversion requiring several millions of years within the Pleistocene is necessary to bring about the degree of inversion that is expressed in the watershed. Indeed, some of these ancient alluvial and colluvial remnants may date back into the Tertiary. Also evident in the watershed, and preserved in the broad, nearly level bottoms of dolines, are multiple deposits of silty material either devoid or nearly devoid of coarse fragments. Recent research indicates that most of this silty material is the result of slope wash processed during the Holocene Age. Residual soils of the watershed were related to the underlying geologic formations by their morphology and types of chert. Colluvial soils were identified and mapped whenever the colluvium thickness exceeded 20 in. (50 cm). Except for the ancient colluvial soils (colluvium without a present-day source area), colluvial soils were not separated according to their geologic age, but stacked colluvial deposits are located in low footslope landforms. Colluvial soils in the watershed were identified and mapped according to their morphologic properties that would influence the perching and subsurface movement of water. Alluvial soils were restricted to present floodplains, low fan terraces, and low fan deltas. Nearly all alluvial soils contained very young surficial sediments derived from slopewash resulting from land clearing and subsequent agricultural activities.

Lietzke, D.A.

1994-01-01

33

Walker River Paiutes: A Tribal History.  

ERIC Educational Resources Information Center

The Northern Paiute people of Nevada's Walker Lake area were known as the Agai Diccutta (Trout Eaters); they called themselves the Numa, or the People. For as long as anyone could recall, they had lived in the area, catching the huge trout from the lake and harvesting the pinon nuts and other foods from the surrounding desert. In the 1820's the…

Johnson, Edward C.

34

Dielectric breakdown patterns and active walker model  

Microsoft Academic Search

Simulations based on the active walker model are used successfully to reconstruct the dielectric breakdown patterns observed in a cell with parallel-plate electrodes. Different types of patterns can be obtained with suitable parameters. These parameters correspond to the electrical and environmental conditions during the breakdown.

Chia-Rong Sheu; Ching-Yen Cheng; Ru-Pin Pan

1999-01-01

35

Baby walkers . . . time to take a stand?  

Microsoft Academic Search

Experience in our hospital and figures from the Home Accident Surveillance System indicate that the number of accidents involving baby walkers is increasing. Safety specifications issued by the British Standards Institution are rarely, if ever, met in full by manufacturers. Home accident prevention measures have been shown to be of limited benefit. We advocate more stringent implementation of safety features

D N Gleadhill; W J Robson; R E Cudmore; R R Turnock

1987-01-01

36

Psychiatric misdiagnoses in Dandy-Walker variant.  

PubMed

Cases of intellectual impairment and aberrant behavior in patients with cerebellar diseases have been described since the early nineteenth century. Here, we report on a patient suffering from Dandy-Walker variant who presented with symptoms of obsessive compulsive disorder and delusional disorder. The current findings emphasize the potential relevance of focal cerebellar lesions as organic correlates of these disorders. PMID:25058305

Blaettner, C; Pfaffenberger, N M; Cartes-Zumelzu, F; Hofer, A

2015-08-01

37

Temperature Preference of Grylloblatta campodeiformis Walker  

Microsoft Academic Search

DURING the field season of 1956, I was able to collect a number of living Grylloblatta campodeiformis Walker, some of which I have maintained in the laboratory. The insects are held in individual plastic boxes almost filled with rotten wood and kept in a refrigerator at 4.5° C. After six months, six nymphs remain active and apparently in good condition.

W. R. Henson

1957-01-01

38

Unusual manifestation of Marden-Walker syndrome  

PubMed Central

Marden-Walker syndrome (MWS) is characterized by multiple joint contractures, a mask-like face with blepharophimosis, micrognathia, high-arched or cleft palate, low-set ears, decreased muscular bulk, arachnodactyly, and kyphoscoliosis. We report a case of MWS along with unusual manifestation of neurological, cardiovascular, and genitourinary system. PMID:23162309

Taksande, Amar M.; Vilhekar, K. Y.

2012-01-01

39

Mark Walker Director of Public Affairs  

E-print Network

, Suite 1100 Portland, OR 97204 Mr. Walker: Please accept these comments from Emerald People's Utility future? Yes, this issue needs to be resolved in the near future. We believe that Emerald resources could lead to energy shortages and higher prices. Emerald is specifically interested in going

40

Groupoidified Linear Algebra Christopher D. Walker  

E-print Network

Groupoidified Linear Algebra Christopher D. Walker (Joint work with John Baez and James Dolan and James Dolan Groupoidified Linear Algebra #12;There is a systematic process (first described by James Linear Algebra #12;There is a systematic process (first described by James Dolan) called

Baez, John

41

Scaling Games to Epic Proportions Walker White  

E-print Network

and video game software sales in 2005 were $7.0 billion dollars [3]. While graphics have always motivated for choosing plays in sports games; natural language processing has been used for character interaction in FacScaling Games to Epic Proportions Walker White Cornell University Ithaca, NY 14853, USA wmwhite

Keinan, Alon

42

Sara Walker | Physical Sciences in Oncology  

Cancer.gov

Sara Walker works in the School of Life Science and the Beyond Center at Arizona State University. She is also a NASA Astrobiology fellow. She spoke about the deep evolutionary history of life on earth and it’s routes to cancer.

43

Modern lacustrine stromatolites, Walker Lake, Nevada  

NASA Astrophysics Data System (ADS)

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.

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

1982-05-01

44

Conformally Friedmann-Lemaitre-Robertson-Walker cosmologies  

E-print Network

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...

Visser, Matt

2015-01-01

45

Speed and Exercise Intensity of Recreational Walkers  

Microsoft Academic Search

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

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

2002-01-01

46

Auditory perception of a human walker.  

PubMed

When one hears footsteps in the hall, one is able to instantly recognise it as a person: this is an everyday example of auditory biological motion perception. Despite the familiarity of this experience, research into this phenomenon is in its infancy compared with visual biological motion perception. Here, two experiments explored sensitivity to, and recognition of, auditory stimuli of biological and nonbiological origin. We hypothesised that the cadence of a walker gives rise to a temporal pattern of impact sounds that facilitates the recognition of human motion from auditory stimuli alone. First a series of detection tasks compared sensitivity with three carefully matched impact sounds: footsteps, a ball bouncing, and drumbeats. Unexpectedly, participants were no more sensitive to footsteps than to impact sounds of nonbiological origin. In the second experiment participants made discriminations between pairs of the same stimuli, in a series of recognition tasks in which the temporal pattern of impact sounds was manipulated to be either that of a walker or the pattern more typical of the source event (a ball bouncing or a drumbeat). Under these conditions, there was evidence that both temporal and nontemporal cues were important in recognising theses stimuli. It is proposed that the interval between footsteps, which reflects a walker's cadence, is a cue for the recognition of the sounds of a human walking. PMID:25638938

Cottrell, David; Campbell, Megan E J

2014-01-01

47

Passive random walkers and riverlike networks on growing surfaces  

NASA Astrophysics Data System (ADS)

Passive random walker dynamics is introduced on a growing surface. The walker is designed to drift upward or downward and then follow specific topological features, such as hill tops or valley bottoms, of the fluctuating surface. The passive random walker can thus be used to directly explore scaling properties of otherwise somewhat hidden topological features. For example, the walker allows us to directly measure the dynamical exponent of the underlying growth dynamics. We use the Kardar-Parisi-Zhang (KPZ) -type surface growth as an example. The world lines of a set of merging passive walkers show nontrivial coalescence behaviors and display the riverlike network structures of surface ridges in space-time. In other dynamics, such as Edwards-Wilkinson growth, this does not happen.The passive random walkers in KPZ-type surface growth are closely related to the shock waves in the noiseless Burgers equation. We also briefly discuss their relations to the passive scalar dynamics in turbulence.

Chin, Chen-Shan

2002-08-01

48

Patterns of motion for random walkers under holonomic constraints  

NASA Astrophysics Data System (ADS)

As models for polymer diffusion we consider the motion in two dimensions and three dimensions of four random walkers restricted by different holonomic constraints. The random walkers perform uncorrelated steps, which obey algebraic waiting-time distributions. We provide numerical results for the centre-of-mass motion and analytical approximations for the short- and long-time diffusion constants. Distinct from the two- and three-walkers problem we encounter here - depending on the constraints - partial nontrivial decoupling of the motion.

Walser, M. W.; Sokolov, I. M.; Blumen, A.

1997-08-01

49

Obituary: Robert Mowbray Walker, 1929-2004  

NASA Astrophysics Data System (ADS)

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

Schoenherr, Neil T.

2004-12-01

50

Walker-Wang models and axion electrodynamics  

NASA Astrophysics Data System (ADS)

We connect a family of gauge theories (Maxwell theories with a magnetoelectric coupling ? =2 ? k ,k ?Z ) to the family of 3D topological lattice models introduced by Walker and Wang. In particular, we show that the lattice Hamiltonians capture a certain strong-coupling limit of these gauge theories, in which the system enters a gapped (confined) phase. We discuss the relationship between the topological order exhibited by certain of these lattice Hamiltonians and the characteristic electromagnetic response of the symmetry-protected bosonic topological insulator.

von Keyserlingk, C. W.; Burnell, F. J.

2015-01-01

51

Actuating a Simple 3D Passive Dynamic Walker Russ Tedrake  

E-print Network

. INTRODUCTION In the late 1980's, Tad McGeer [1] introduced a class of walking robots, known as passive dynamicActuating a Simple 3D Passive Dynamic Walker Russ Tedrake Computer Science and Artificial-- The passive dynamic walker described in this paper is a robot with a minimal number of degrees of freedom

Tedrake, Russ

52

Hazards of baby walkers in a European context  

Microsoft Academic Search

OBJECTIVES: To identify conditions related to baby walker injuries in a Greek population. DESIGN: Analysis of all baby walker related injuries recorded during a 12 month period by the childhood injury surveillance system established in one of the two teaching hospitals for children serving the population of Athens. SETTING: Emergency clinics of A Kyriakou Children's Hospital in Athens, Greece. SUBJECTS:

E. Petridou; E. Simou; C. Skondras; G. Pistevos; P. Lagos; G. Papoutsakis

1996-01-01

53

Asymmetric Passive Dynamic Walker Used to Examine Gait Rehabilitation Methods  

Microsoft Academic Search

Testing gait rehabilitation devices on humans can be a difficult task, due to the effects of the neurological controls of the human body. This thesis advances the use of a passive dynamic walker (PDW) tuned to have asymmetric gait patterns similar to those with\\u000aphysical impairments to test rehabilitation devices. A passive dynamic walker is a multipendulum system that has

John Sushko

2011-01-01

54

Iain S. Walker1 and Max H. Sherman1  

E-print Network

and Construction Sealants and Adhesives, ASTM STP 1453, A. Wolf Ed., American Society for Testing and MaterialsLBNL 50189 1 Iain S. Walker1 and Max H. Sherman1 Sealant Longevity for Residential Ducts Reference: Walker, I.S. and Sherman, M.H., "Sealant Longevity for Residential Ducts," Durability of Building

55

The World Function in Robertson-Walker Spacetime  

E-print Network

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.

Mark D. Roberts

1999-05-02

56

A business plan for iXa walker  

E-print Network

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 ...

Morton, Stephen A

2010-01-01

57

Department of Mechanical Engineering Spring 2013 Intelligent Walker for Retirees  

E-print Network

PENNSTATE Department of Mechanical Engineering Spring 2013 Intelligent Walker for Retirees Overview a walker with "intelligent" features such as a moving arm, auto- braking wheels, and a control system for sensing the user · Design an electronic system which assists the user in using the moving arm · Design

Demirel, Melik C.

58

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)....

59

Older Homebound Women: Negotiating Reliance on a Cane or Walker  

PubMed Central

Canes and walkers are commonly characterized as assistive devices and as devices that serve the same purpose, as walking aides. These general views were reappraised and tempered in this descriptive phenomenological study with 40 older women (aged 85-98) who were unable to leave their homes without help. The purpose was to describe the phenomena of negotiating reliance on canes and walkers as walking devices and the lifeworld context underlying each phenomenon. Relative to lifeworld, there were differences between coming to terms with using a cane and coming to terms with using a walker. Data revealed similarities and distinctions between the basic intentions of relying on canes and on walkers and the associated purposes served by canes and walkers. Participants did not view either device as consistently assistive. Findings evoke opportunities for dialogue among older persons, scholars, practitioners, and designers of these devices about coming to terms with such devices and relying on them. PMID:21041520

Porter, Eileen J.; Benson, Jacquelyn J.; Matsuda, Sandy

2012-01-01

60

David Alan Walker (1928-2012).  

PubMed

David Alan Walker, Emeritus Professor of Biology, University of Sheffield, UK and Fellow of the Royal Society, died on February 13, 2012. David had a marvelous 60 year career as a scientist, during which he was a researcher, mentor, valued colleague, and a prolific writer in the field of photosynthesis. His career was marked by creative breakthroughs in isolation and analysis of chloroplast metabolism in vitro and simple but valuable technical advances for measurement of photosynthesis in vivo that remain relevant on a global scale to production of crops and biofuels, as well as plant responses to climate change. We include here personal remembrances by the authors (GEE and UH), and by (in alphabetical order): Zoran Cerovic (France), Bob Furbank (Australia), Geoffrey Hind (USA), John Humby (UK), Agu Laisk (Estonia), Peter Lea (UK), Ross Lilley (Australia), Barry Osmond (Australia), Simon Robinson (Australia) and Charles Stirling (UK). PMID:22638915

Edwards, Gerald E; Heber, Ulrich

2012-06-01

61

75 FR 38833 - Walker River Basin Acquisition Program  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF THE INTERIOR Bureau of Reclamation Walker River Basin Acquisition Program AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of cancellation...SUMMARY: The Bureau of Reclamation (Reclamation) is canceling...

2010-07-06

62

Walker's Critique of Religion in "The Color Purple."  

ERIC Educational Resources Information Center

Highlights religious themes in Alice Walker's "The Color Purple," especially Celie's struggle with traditional Christianity, which here serves to reinforce oppression. Her journey toward spiritual independence reflects much of the actual religious experience of Black women in America. (DM)

Mercer, Calvin

1989-01-01

63

Interaction of two walkers: Wave-mediated energy and force  

NASA Astrophysics Data System (ADS)

A bouncing droplet, self-propelled by its interaction with the waves it generates, forms a classical wave-particle association called a "walker." Previous works have demonstrated that the dynamics of a single walker is driven by its global surface wave field that retains information on its past trajectory. Here we investigate the energy stored in this wave field for two coupled walkers and how it conveys an interaction between them. For this purpose, we characterize experimentally the "promenade modes" where two walkers are bound and propagate together. Their possible binding distances take discrete values, and the velocity of the pair depends on their mutual binding. The mean parallel motion can be either rectilinear or oscillating. The experimental results are recovered analytically with a simple theoretical framework. A relation between the kinetic energy of the droplets and the total energy of the standing waves is established.

Borghesi, Christian; Moukhtar, Julien; Labousse, Matthieu; Eddi, Antonin; Fort, Emmanuel; Couder, Yves

2014-12-01

64

Interaction of two walkers: wave-mediated energy and force.  

PubMed

A bouncing droplet, self-propelled by its interaction with the waves it generates, forms a classical wave-particle association called a "walker." Previous works have demonstrated that the dynamics of a single walker is driven by its global surface wave field that retains information on its past trajectory. Here we investigate the energy stored in this wave field for two coupled walkers and how it conveys an interaction between them. For this purpose, we characterize experimentally the "promenade modes" where two walkers are bound and propagate together. Their possible binding distances take discrete values, and the velocity of the pair depends on their mutual binding. The mean parallel motion can be either rectilinear or oscillating. The experimental results are recovered analytically with a simple theoretical framework. A relation between the kinetic energy of the droplets and the total energy of the standing waves is established. PMID:25615197

Borghesi, Christian; Moukhtar, Julien; Labousse, Matthieu; Eddi, Antonin; Fort, Emmanuel; Couder, Yves

2014-12-01

65

Her Blue Body*: A Pagan Reading of Alice Walker Womanism  

Microsoft Academic Search

This essay explores the earth-based woman-centered paganism found in Alice Walker's womanist writings. It argues that Walker's visionary landscape is influenced by indigenous spirituality and woman-centered Goddess beliefs which place humans in a sacred web of life that includes plants, animals, elemental forces, the earth, the cosmos, and the living and the dead. In this landscape, humans are not stewards

Arisika Razak

2009-01-01

66

Velocity addition formulas in Robertson-Walker spacetimes  

E-print Network

Universal velocity addition formulas analogous to the well-known formula in special relativity are found for four geometrically defined relative velocities in a large class of Robertson-Walker spacetimes. Explicit examples are given. The special relativity result is recovered as a special case, and it is shown that the spectroscopic relative velocity, in contrast to three other geometric relative velocities, follows the same addition law as in special relativity for comoving observers in Robertson-Walker cosmologies.

Klein, David

2015-01-01

67

STS-69 Mission Commander David M. Walker suits up  

NASA Technical Reports Server (NTRS)

STS-69 Mission Commander David M. Walker signals he's ready to fly as he finishes donning his launch/entry suit in the Operations and Checkout Building. Walker, who is embarking on his fourth trip into space, will depart shortly for Launch Pad 39A along with four fellow crew members. Awaiting the crew and liftoff at 11:09 a.m. EDT is the Space Shuttle Endeavour.

1995-01-01

68

Initial conditions of a simple passive-dynamic walker  

NASA Astrophysics Data System (ADS)

Walking robots hold great potential for the future of military robotics. Their natural agility in rough, unstructured terrain make them ideal for military applications but their power requirements do not. Passive dynamic walkers offer a potentially low-power solution. This class of legged robots utilize the natural inverted pendular dynamics that humans rely on to locomote. The most basic of these systems uses gravity as its power source and has no control system therefore its stability is heavily reliant on its initial conditions. The VICON Motion Capture System was used to record the motions of Coleman and Ruina's1 TinkertoyWalker. The initial angles and angular velocities of the various trials were extracted from the motion capture data and used as inputs to a multi-body dynamics model of the walker. The model was created to provide insight into passive-dynamic walkers and the interactions between the walker and the ground surface. Several trials were performed to quantify the stability space of the experimental walker and improve the correlation of the dynamics model to the physical robot.

Haueisen, Brooke; Hudas, Greg; Hulbert, Greg; Nebel, Kyle

2006-05-01

69

The Walker Lane Belt in northeastern California  

SciTech Connect

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.

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

1993-04-01

70

X-1E with Pilot Joe Walker  

NASA Technical Reports Server (NTRS)

A photo of the X-1E with pilot Joe Walker suited up at the NASA High-Speed Flight Station, Edwards, California. The dice and 'Little Joe' are prominently displayed under the cockpit area. (Little Joe is a dice players slang term for two deuces.) Five years later when Walker reached 354,200 feet in the X-15, that aircraft carried similar artwork - 'Little Joe the II.' Walker is shown in the photo above wearing an early partial pressure suit. This protected the pilot if cockpit pressure was lost above 50,000 feet. There were five versions of the Bell X-1 rocket-powered research aircraft that flew at the NACA High-Speed Flight Research Station, Edwards, California. The bullet-shaped X-1 aircraft were built by Bell Aircraft Corporation, Buffalo, N.Y. for the U.S. Army Air Forces (after 1947, U.S. Air Force) and the National Advisory Committee for Aeronautics (NACA). The X-1 Program was originally designated the XS-1 for EXperimental Sonic. The X-1's mission was to investigate the transonic speed range (speeds from just below to just above the speed of sound) and, if possible, to break the 'sound barrier.' Three different X-1s were built and designated: X-1-1, X-1-2 (later modified to become the X-1E), and X-1-3. The basic X-1 aircraft were flown by a large number of different pilots from 1946 to 1951. The X-1 Program not only proved that humans could go beyond the speed of sound, it reinforced the understanding that technological barriers could be overcome. The X-1s pioneered many structural and aerodynamic advances including extremely thin, yet extremely strong wing sections; supersonic fuselage configurations; control system requirements; powerplant compatibility; and cockpit environments. The X-1 aircraft were the first transonic-capable aircraft to use an all-moving stabilizer. The flights of the X-1s opened up a new era in aviation. The first X-1 was air-launched unpowered from a Boeing B-29 Superfortress on Jan. 25, 1946. Powered flights began in December 1946. On Oct. 14, 1947, the X-1-1, piloted by Air Force Captain Charles 'Chuck' Yeager, became the first aircraft to exceed the speed of sound, reaching about 700 miles per hour (Mach 1.06) and an altitude of 43,000 feet. The number 2 X-1 was modified and redesignated the X-1E. The modifications included adding a conventional canopy, an ejection seat, a low-pressure fuel system of increased capacity, and a thinner high-speed wing. The X-1E was used to obtain in-flight data at twice the speed of sound, with particular emphasis placed on investigating the improvements achieved with the high-speed wing. These wings, made by Stanley Aircraft, were only 3 3/8-inches thick at the root and had 343 gauges installed in them to measure structural loads and aerodynamic heating. The X-1E used its rocket engine to power it up to a speed of 1,471 miles per hour (Mach 2.24) and to an altitude of 73,000 feet. Like the X-1 it was air-launched. The X-1 aircraft were almost 31 feet long and had a wingspan of 28 feet. The X-1 was built of conventional aluminum stressed-skin construction to extremely high structural standards. The X-1E was also 31 feet long but had a wingspan of only 22 feet, 10 inches. It was powered by a Reaction Motors, Inc., XLR-8-RM-5, four-chamber rocket engine. As did all X-1 rocket engines, the LR-8-RM-5 engine did not have throttle capability, but instead, depended on ignition of any one chamber or group of chambers to vary speed. The X-1A, X-1B, and the X-1D were growth versions of the X-1. They were almost five feet longer, almost 2,500 pounds heavier and had conventional canopies. The X-1A and X-1B were modified to have ejection seats. Their mission was to continue the X-1 studies at higher speeds and altitudes. The X-1A began this research after the X-1D was destroyed in an explosion on a captive flight before it made any research flights. On Dec. 12, 1953, Major Charles Yeager flew the X-1A up to a speed of 1,612 miles per hour (almost two-and-a-half times the speed of sound). Then on Aug. 26, 1954, Major Arthur Murray took the X-1A up to an altitude of 90,4

1958-01-01

71

Quantum Walk-based Generation of Entanglement Between Two Walkers  

E-print Network

Quantum walks can be used either as tools for quantum algorithm development or as entanglement generators, potentially useful to test quantum hardware. We present a novel algorithm based on a discrete Hadamard quantum walk on a line with one coin and two walkers whose purpose is to generate entanglement between walkers. We provide several classical computer simulations of our quantum algorithm in which we show that, although the asymptotical amount of entanglement generated between walkers does not reach the highest degree of entanglement possible at each step for either coin measurement outcome, the entanglement ratio (entanglement generated/highest value of entanglement possible, for each step) tends to converge, and the actual convergence value depends on the coin initial state and on the coin measurement outcome. Furthermore, our numerical simulations show that, for the quantum walks used in our algorithm, the value towards which entanglement ratio converges also depends on the position probability distribution symmetry of a quantum walk computed with one single walker and the same coin initial state employed in the corresponding quantum walk with two walkers.

Salvador E. Venegas-Andraca; Sougato Bose

2009-01-26

72

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

PubMed

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

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

2014-10-01

73

Quantum Walk-based Generation of Entanglement Between Two Walkers  

E-print Network

Quantum walks can be used either as tools for quantum algorithm development or as entanglement generators, potentially useful to test quantum hardware. We present a novel algorithm based on a discrete Hadamard quantum walk on a line with one coin and two walkers whose purpose is to generate entanglement between walkers. We provide several classical computer simulations of our quantum algorithm in which we show that, although the asymptotical amount of entanglement generated between walkers does not reach the highest degree of entanglement possible at each step for either coin measurement outcome, the entanglement ratio (entanglement generated/highest value of entanglement possible, for each step) tends to converge, and the actual convergence value depends on the coin initial state and on the coin measurement outcome. Furthermore, our numerical simulations show that, for the quantum walks used in our algorithm, the value towards which entanglement ratio converges also depends on the position probability distri...

Venegas-Andraca, Salvador E

2009-01-01

74

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

E-print Network

The Purpose Of this study was threefold: (1) to provide an examination Of the attentional demands of ambulating with two commonly prescribed walking aids (a standard Walker and a rolling walker) in a non-patient Population,, (2) to replicate...

Cowley, Tammara Kemp

1994-01-01

75

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

E-print Network

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

Provancher, William

76

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

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

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

2015-01-01

77

Statement of Facts for 1994 City-Wide Mock Trial Competitions. Scott Walker v. Tanya Brewster.  

ERIC Educational Resources Information Center

Prepared by the District of Columbia Street Law Project for its 23rd annual city-wide mock trial competition, this instructional handout provides the material for a mock civil trial over an accidental shooting. Thirteen-year-old T. J. Walker, Scott Walker's son from a previous marriage, visited the home of 5-year-old Jesse Walker with a pistol…

National Inst. for Citizen Education in the Law, Washington, DC.

78

Alice Walker in the Classroom: "Living by the Word." The NCTE High School Literature Series.  

ERIC Educational Resources Information Center

This small book is a handy guide for bringing the work of author Alice Walker into the classroom. It includes biographical information, ideas for literature circles using Walker's short stories, sample writing lessons using Walker's poems, suggestions for teaching "The Color Purple," and a wealth of resources for further investigation of Alice…

Jago, Carol

79

Alice Walker's Politics or the Politics of "The Color Purple."  

ERIC Educational Resources Information Center

Alice Walker's "The Color Purple" portrays Black women's oppression as the result of patriarchy, and proposes the acceptance of middle-class values--home ownership and entrepreneurship--as the solution to exploitation. She relies on stereotypes to characterize Black men and women, and depicts an ideology of submission. (BJV)

Hamilton, Cynthia

1988-01-01

80

Efficient Bipedal Robots Based on Passive-Dynamic Walkers  

Microsoft Academic Search

Passive-dynamic walkers are simple mechanical devices, composed of solid parts connected by joints, that walk stably down a slope. They have no motors or controllers, yet can have remarkably humanlike motions. This suggests that these machines are useful models of human locomotion; however, they cannot walk on level ground. Here we present three robots based on passive-dynamics, with small active

Steve Collins; Andy Ruina; Russ Tedrake; Martijn Wisse

2005-01-01

81

Neutrino wave equation in the Robertson-Walker geometry  

NASA Astrophysics Data System (ADS)

The massless Dirac equation is separated in the Robertson-Walker geometry. The Schrödinger-like one-dimensional equation to which the problem is reduced is shown to admit a discrete positive spectrum. The existence or nonexistence of the discrete neutrino energy spectrum is connected, in the case of the standard cosmology, with the assumption that the universe is closed or not.

Montaldi, Emilio; Zecca, Antonio

1994-05-01

82

Selling Out Mothers and Babies by Marsha Walker  

PubMed Central

The monitoring project reported in Marsha Walker's book, Selling Out Mothers and Babies, offers a qualitative assessment of formula companies' unethical marketing practices in the United States. The book presents extensive documentation on the questionable strategies of formula companies and how they avoid and circumvent recommendations of the International Code of Marketing of Breast Milk Substitutes.

Sandra M., Gossler

2003-01-01

83

Do mitochondria recombine in humans? Adam Eyre-Walker  

E-print Network

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

Eyre-Walker, Adam

84

[U.S. Fish and Wildlife Service letterhead] Mark Walker  

E-print Network

Compensation Program) by the Service. Enclosed are a number of general comments on the report as well[U.S. Fish and Wildlife Service letterhead] Mark Walker Director, Public Affairs Division Northwest and Wildlife Service (Service) appreciates the opportunity to comment on the Artificial Production Review Phase

85

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

86

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

87

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

88

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

89

INTERIOR VIEW WITH STIFF LEG LADLE CRANE OPERATOR, LUKE WALKER, ...  

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

INTERIOR VIEW WITH STIFF LEG LADLE CRANE OPERATOR, LUKE WALKER, POURING OFF SLAG FROM LADLE AS SKIMMER, BRUCE ELLIOTT, RAKES THE SLAG FROM THE MOLTEN METAL. - American Cast Iron Pipe Company, Mixer Building, 1501 Thirty-first Avenue North, Birmingham, Jefferson County, AL

90

How clonal are human mitochondria? Adam Eyre-Walker*  

E-print Network

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

Eyre-Walker, Adam

91

Roy Lee Walker Elementary School, McKinney ISD. [Videotape].  

ERIC Educational Resources Information Center

This 7:50-minute videotape describes the architectural design and structure of the Roy Lee Walker Elementary School, illustrating why the school is considered the most energy efficient and environmentally sound school ever built. The videotape highlights the sustainable, award-winning design features such as the innovative use of daylight to…

SHW Group, Inc., Dallas, TX.

92

Bathymetry of Walker Lake, West-Central Nevada  

USGS Publications Warehouse

Walker Lake lies within a topographically closed basin in west-central Nevada and is the terminus of the Walker River. Much of the streamflow in the Walker River is diverted for irrigation, which has contributed to a decline in lake-surface altitude of about 150 feet and an increase in dissolved solids from 2,500 to 16,000 milligrams per liter in Walker Lake since 1882. The increase in salinity threatens the fresh-water ecosystem and survival of the Lahontan cutthroat trout, a species listed as threatened under the Endangered Species Act. Accurately determining the bathymetry and relations between lake-surface altitude, surface area, and storage volume are part of a study to improve the water budget for Walker Lake. This report describes the updated bathymetry of Walker Lake, a comparison of results from this study and a study by Rush in 1970, and an estimate of the 1882 lake-surface altitude. Bathymetry was measured using a single-beam echosounder coupled to a differentially-corrected global positioning system. Lake depth was subtracted from the lake-surface altitude to calculate the altitude of the lake bottom. A Lidar (light detection and ranging) survey and high resolution aerial imagery were used to create digital elevation models around Walker Lake. The altitude of the lake bottom and digital elevation models were merged together to create a single map showing land-surface altitude contours delineating areas that are currently or that were submerged by Walker Lake. Surface area and storage volume for lake-surface altitudes of 3,851.5-4,120 feet were calculated with 3-D surface-analysis software. Walker Lake is oval shaped with a north-south trending long axis. On June 28, 2005, the lake-surface altitude was 3,935.6 feet, maximum depth was 86.3 feet, and the surface area was 32,190 acres. The minimum altitude of the lake bottom from discrete point depths is 3,849.3 feet near the center of Walker Lake. The lake bottom is remarkably smooth except for mounds near the shore and river mouth that could be boulders, tree stumps, logs, or other submerged objects. The echosounder detected what appeared to be mounds in the deepest parts of Walker Lake, miles from the shore and river mouth. However, side-scan sonar and divers did not confirm the presence of mounds. Anomalies occur in two northwest trending groups in northern and southern Walker Lake. It is hypothesized that some anomalies indicate spring discharge along faults based on tufa-like rocks that were observed and the northwest trend parallel to and in proximity of mapped faults. Also, evaporation measured from Walker Lake is about 50 percent more than the previous estimate, indicating more water is flowing into the lake from sources other than the Walker River. Additional studies need to be done to determine what the anomalies are and whether they are related to the hydrology of Walker Lake. Most differences in surface area and storage volume between this study and a study by Rush in 1970 were less than 1 percent. The largest differences occur at lake-surface altitudes less than 3,916 feet. In general, relations between lake-surface altitude, surface area, and storage volume from Rush's study and this study are nearly identical throughout most of the range in lake-surface altitude. The lake-surface altitude in 1882 was estimated to be between 4,080 feet and 4,086 feet with a probable altitude of 4,082 feet. This estimate compares well with two previous estimates of 4,083 feet and 4,086 feet. Researchers believe the historic highstand of Walker Lake occurred in 1868 and estimated the highstand was between 4,089 feet and 4,108 feet. By 1882, Mason Valley was predominantly agricultural. The 7-26 feet decline in lake-surface altitude between 1868 and 1882 could partially be due to irrigation diversions during this time.

Lopes, Thomas J.; Smith, J. LaRue

2007-01-01

93

Molecular mechanisms of auxin action Loni Walker and Mark Estelle  

E-print Network

434 Molecular mechanisms of auxin action Loni Walker and Mark Estelle The plant growth hormone auxin has an important role in a variety of plant growth and developmental processes. Identification of transcription factors, some with defined genetic function, has shed new light on the mechanisms of auxin

Estelle, Mark

94

Mary Edwards Walker: the soul ahead of her time.  

PubMed

Mary Edwards Walker was a gallant woman who stood for women's rights, embodied the true American spirit, and served the Union Army in the Civil War as a surgeon. She later became the first and only woman in United States history to be awarded the Congressional Medal of Honor. PMID:25535874

Rehman, Atiq; Rahman, Naba G; Harris, Sharon M; Cheema, Faisal H

2015-02-01

95

Finding the Right Formula: Edwin H. Walker Jr  

ERIC Educational Resources Information Center

Edwin H. Walker Jr earned his doctorate in chemistry at age 27 and has barely looked back. With 13 publications under his belt before coming out of graduate school, he has also given more than 20 poster presentations in national venues, most recently at the American Chemical Society. He can also include securing a half-million-dollar National…

Keels, Crystal L.

2005-01-01

96

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

97

16 CFR 1216.2 - Requirements for infant walkers.  

Code of Federal Regulations, 2013 CFR

...the test platform facing forward so that Plane A is perpendicular to the front edge of...forward in a straight line parallel to Plane A. (ii) [Reserved] (7) Instead...weight to the front of the walker base at Plane A by means of a 7-strand military...

2013-01-01

98

16 CFR 1216.2 - Requirements for infant walkers.  

Code of Federal Regulations, 2011 CFR

...the test platform facing forward so that Plane A is perpendicular to the front edge of...forward in a straight line parallel to Plane A. (ii) [Reserved] (7) Instead...weight to the front of the walker base at Plane A by means of a 7-strand military...

2011-01-01

99

16 CFR 1216.2 - Requirements for infant walkers.  

Code of Federal Regulations, 2012 CFR

...the test platform facing forward so that Plane A is perpendicular to the front edge of...forward in a straight line parallel to Plane A. (ii) [Reserved] (7) Instead...weight to the front of the walker base at Plane A by means of a 7-strand military...

2012-01-01

100

General Transformation Formulas for Fermi-Walker Coordinates  

E-print Network

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.

David Klein; Peter Collas

2008-06-27

101

Dynamic micromagnetic simulation of domain wall around the Walker breakdown in ferromagnetic nanowires driven magnetic pulse  

NASA Astrophysics Data System (ADS)

We have investigated the domain wall dynamic around the Walker breakdown field in ferromagnetic nanowires by means of micromagnetic simulation. The simulation is driven by short magnetic pulse 1-ns length with a systematic variation of applied magnetic strength. Interestingly, it is found that the domain wall structure exhibits transverse domain wall structure before the Walker breakdown field while the vortex/antivortex domain wall structure after the Walker breakdown field. The domain wall velocity increases as the applied field strength increases before the Walker breakdown field and decreases after the Walker breakdown field. The Walker breakdown field decreases as the width and the thickness of nanowires increases. We also analyzed the energy magnetization density system around the Walker breakdown field. It is revealed that the magnetostatic energy dominates of the energy system and the exchange energy tendency increases as the vortex/antivortex structures is formed in ferromagnetic nanowires.

Djuhana, D.; Manaf, A.; Sumarta, A.; Mardona, Kim, D.-H.

2014-03-01

102

Friedmann-Robertson-Walker-like cosmologies with spherical symmetry  

NASA Astrophysics Data System (ADS)

We reconsider the cosmological model discussed by Sung-Won Kim [Phys. Rev. D 53, 6889 (1996)] in the context of Friedmann-Robertson-Walker cosmologies with a traversable wormhole, where it is assumed that the matter content is divided into two parts: the cosmic part that depends on time only and the wormhole part that depends on space only. The cosmic part obeys the barotropic equation of state pc=??c. The complete analysis requires further care and reveals more interesting results than what was previously shown by the author. They can be readily applied to the evolution of a large class of cosmological models which are more general than Friedmann-Robertson-Walker models.

Cataldo, Mauricio; Aróstica, Fernanda; Bahamonde, Sebastian

2013-08-01

103

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

104

From classical chaos to decoherence in Robertson-Walker cosmology  

E-print Network

We analyse the relationship between classical chaos and particle creation in Robertson-Walker cosmological models with gravity coupled to a scalar field. Within our class of models chaos and particle production are seen to arise in the same cases. Particle production is viewed as the seed of decoherence, which both enables the quantum to classical transition, and ensures that the correspondence between the quantum and classically chaotic models will be valid

Fernando C. Lombardo; Mario Castagnino; Luca Bombelli

1999-03-23

105

The Enigmatic Young Object: Walker 90/V590 Monocerotis  

E-print Network

We assess the evolutionary status of the intriguing object Walker 90/V590 Mon, which is located about 20 arcminutes northwest of the Cone Nebula near the center of the open cluster NGC 2264. This object, according to its most recent optical spectral type determination (B7), which we confirmed, is at least 3 magnitudes too faint in V for the cluster distance, but it shows the classical signs of a young pre-main sequence object, such as highly variable Halpha emission, Mg II emission, IR excess, UV continuum, and optical variability. We analyzed a collection of archival and original data on Walker 90, covering 45 years including photometry, imaging, and spectroscopic data ranging from ultraviolet to near-infrared wavelengths. According to star formation processes, it is expected that, as this object clears its primordial surroundings, it should become optically brighter, show a weakening of its IR excess and present decreasing line emissions. This behavior is supported by our observations and analysis, but timescales are expected to be longer than the one observed here. Based on photometric data secured in 2007, we find Walker 90 at its brightest recorded optical magnitude. We document an evolution in spectral type over the past five decades (from A2/A3 to currently B7 and as early as B4), along with a decrease in the near-infrared K fluxes. From near-infrared images secured in 2004, Walker 90 appears as a point source placing an upper limit of 0.1 arcsec for its diameter. We conclude that many observational features are explained if W90 is a flared disk system, surrounded by an inclined optically thick accretion disk.

Mario R. Perez; Bruce McCollum; Mario E. van den Ancker; Michael D. Joner

2008-05-27

106

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

E-print Network

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.

Ovidiu-Cristinel Stoica

2012-08-07

107

Record of Diglyphus walker (Hymenoptera: Eulophidae) species in Brazil.  

PubMed

Leafminers (Diptera: Agromyzidae) are pests of various crops, mainly in greenhouses, and have Diglyphus spp. as important leafminer larval parasitoids. Until recently, only Diglyphus insularis (Gahan) had been reported in Brazil. In here we report the first records of Diglyphus begini (Ashmead), D. intermedius (Girault) and D. isaea (Walker) in Brazil. These parasitoids were found parasitizing leafminer larvae on cultivated and spontaneous plants in some areas of Minas Gerais state, Brazil. PMID:21584416

Carvalho, A R; Bueno, V H P; Silva, D B; Costa, V A

2011-01-01

108

Uniqueness of complete spacelike hypersurfaces of constant mean curvature in generalized Robertson-Walker spacetimes  

Microsoft Academic Search

A new technique is introduced in order to solve the following question:When is a complete spacelike hypersurface of constant mean curvature in a generalized Robertson-Walker spacetime totally umbilical and a slice? (Generalized Robertson-Walker spacetimes extend classical Robertson-Walker ones to include the cases in which the fiber has not constant sectional curvature.) First, we determine when this hypersurface must be compact.

Luis J. Alías; Alfonso Romero; Miguel Sánchez

1995-01-01

109

Rationality of spectral action for Robertson-Walker metrics  

NASA Astrophysics Data System (ADS)

We use pseudodifferential calculus and heat kernel techniques to prove a conjecture by Chamseddine and Connes on rationality of the coefficients of the polynomials in the cosmic scale factor a( t) and its higher derivatives, which describe the general terms a 2 n in the expansion of the spectral action for general Robertson-Walker metrics. We also compute the terms up to a 12 in the expansion of the spectral action by our method. As a byproduct, we verify that our computations agree with the terms up to a 10 that were previously computed by Chamseddine and Connes by a different method.

Fathizadeh, Farzad; Ghorbanpour, Asghar; Khalkhali, Masoud

2014-12-01

110

Efficient bipedal robots based on passive-dynamic walkers.  

PubMed

Passive-dynamic walkers are simple mechanical devices, composed of solid parts connected by joints, that walk stably down a slope. They have no motors or controllers, yet can have remarkably humanlike motions. This suggests that these machines are useful models of human locomotion; however, they cannot walk on level ground. Here we present three robots based on passive-dynamics, with small active power sources substituted for gravity, which can walk on level ground. These robots use less control and less energy than other powered robots, yet walk more naturally, further suggesting the importance of passive-dynamics in human locomotion. PMID:15718465

Collins, Steve; Ruina, Andy; Tedrake, Russ; Wisse, Martijn

2005-02-18

111

``Natural'' Vacua in Hyperbolic Friedmann-Robertson-Walker Spacetimes  

E-print Network

Recent evidence indicates that the Universe is open, i.e., spatially hyperbolic, longstanding theoretical preferences to the contrary notwithstanding. This makes it possible to select a vacuum state, Fock space, and particle definition for a quantized field, by requiring concordance with ordinary flat-spacetime theory at late times. The particle-number basis states thus identified span the physical state space of the field at all times. This construction is demonstrated here explicitly for a massive, minimally coupled, linear scalar field in an open, radiation-dominated Friedmann-Robertson-Walker spacetime.

Ian H. Redmount

1999-04-30

112

A reply to Walker’s note: A comment on Ta?iran’s ‘Wage and income effects on the timing and spacing of births in Sweden and in the United States’  

Microsoft Academic Search

.   Walker (1997) criticizes one of the conclusions in my book Tas¸\\\\iran (1995), that Heckman and Walker’s very high negative\\u000a wage rate and positive income effects on Swedish fertility are very sensitive. In this paper, I explain, first, that my results\\u000a are not only based on the series Walker mentions, but also on other series in both SFS and HUS

Ali C. Ta?iran

2002-01-01

113

Dissemination of Walker 256 carcinoma cells to rat skeletal muscle  

SciTech Connect

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.

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

1986-03-05

114

Monocoque structure for the SKITTER three-legged walker  

NASA Astrophysics Data System (ADS)

The SKITTER 2 design is a monocoque version of the proposed lunar three-legged walker. By the definition of monocoque, the body and legs are a shell with no internal ribbing or supports added for absorbing stresses. The purpose of the monocoque is to encase the elements used for power transmission, power supply, and control of the motion. The material for the structure is a vinyl ester resin, Derakane 8084. This material is easily formable and locally obtainable. The body consists of a hexagonally shaped cylinder with truncated hexagonal pyramids on the top and botton. The legs are eight inch diameter cylinders. The legs are comprised of a tibia section and a femur section. The SKITTER 2 is powered by six actuators which provide linear forces that are transformed into rotary torques by a series of chains and sprockets. The joints connect the femur to the body and the tibia to the femur. Surrounding the joints are flexible rubber hoses that fully encase the chains and sprockets. The SKITTER 2 is capable of walking upside down, righting itself after being overturned, and has the ability to perform in many environments. Applications for this walker include lunar transport or drilling, undersea exploration, and operation in severe surroundings such as arctic temperatures or high radiation.

Bansek, Robert N.; Booth, Andrew J.; Daneman, Steven A.; Dresser, James A.; Haney, Todd G.; Johnson, Gregory R.; Lindzen, Eric C.; Montgomery, Robert C.; Warren, Andrew L.

1988-06-01

115

Optimal recruitment strategies for groups of interacting walkers with leaders  

NASA Astrophysics Data System (ADS)

We introduce a model of interacting random walkers on a finite one-dimensional chain with absorbing boundaries or targets at the ends. Walkers are of two types: informed particles that move ballistically towards a given target and diffusing uninformed particles that are biased towards close informed individuals. This model mimics the dynamics of hierarchical groups of animals, where an informed individual tries to persuade and lead the movement of its conspecifics. We characterize the success of this persuasion by the first-passage probability of the uninformed particle to the target, and we interpret the speed of the informed particle as a strategic parameter that the particle can tune to maximize its success. We find that the success probability is nonmonotonic, reaching its maximum at an intermediate speed whose value increases with the diffusing rate of the uninformed particle. When two different groups of informed leaders traveling in opposite directions compete, usually the largest group is the most successful. However, the minority can reverse this situation and become the most probable winner by following two different strategies: increasing its attraction strength or adjusting its speed to an optimal value relative to the majority's speed.

Martínez-García, Ricardo; López, Cristóbal; Vazquez, Federico

2015-02-01

116

Monocoque structure for the SKITTER three-legged walker  

NASA Technical Reports Server (NTRS)

The SKITTER 2 design is a monocoque version of the proposed lunar three-legged walker. By the definition of monocoque, the body and legs are a shell with no internal ribbing or supports added for absorbing stresses. The purpose of the monocoque is to encase the elements used for power transmission, power supply, and control of the motion. The material for the structure is a vinyl ester resin, Derakane 8084. This material is easily formable and locally obtainable. The body consists of a hexagonally shaped cylinder with truncated hexagonal pyramids on the top and botton. The legs are eight inch diameter cylinders. The legs are comprised of a tibia section and a femur section. The SKITTER 2 is powered by six actuators which provide linear forces that are transformed into rotary torques by a series of chains and sprockets. The joints connect the femur to the body and the tibia to the femur. Surrounding the joints are flexible rubber hoses that fully encase the chains and sprockets. The SKITTER 2 is capable of walking upside down, righting itself after being overturned, and has the ability to perform in many environments. Applications for this walker include lunar transport or drilling, undersea exploration, and operation in severe surroundings such as arctic temperatures or high radiation.

Bansek, Robert N.; Booth, Andrew J.; Daneman, Steven A.; Dresser, James A.; Haney, Todd G.; Johnson, Gregory R.; Lindzen, Eric C.; Montgomery, Robert C.; Warren, Andrew L.

1988-01-01

117

Ground reaction forces of Olympic and World Championship race walkers.  

PubMed

Abstract Race walking is an Olympic event where no visible loss of contact should occur and the knee must be straightened until midstance. The purpose of this study was to analyse ground reaction forces of world-class race walkers and associate them with key spatiotemporal variables. Nineteen athletes race walked along an indoor track and made contact with two force plates (1000 Hz) while being filmed using high-speed videography (100 Hz). Race walking speed was correlated with flight time (r = .46, p = .049) and flight distance (r = .69, p = .001). The knee's movement from hyperextension to flexion during late stance meant the vertical push-off force that followed midstance was smaller than the earlier loading peak (p < .001), resulting in a flattened profile. Athletes with narrower stride widths experienced reduced peak braking forces (r = .49, p = .046), peak propulsive forces (r = .54, p = .027), peak medial forces (r = .63, p = .007) and peak vertical push-off forces (r = .60, p = .011). Lower fluctuations in speed during stance were associated with higher stride frequencies (r = .69, p = .001), and highlighted the importance of avoiding too much braking in early stance. The flattened trajectory and consequential decrease in vertical propulsion might help the race walker avoid visible loss of contact (although non-visible flight times were useful in increasing stride length), while a narrow stride width was important in reducing peak forces in all three directions and could improve movement efficiency. PMID:25429613

Hanley, Brian; Bissas, Athanassios

2014-11-27

118

Redeeming Power of Art in Alice Walker's The Color Purple and Possessing the Secret of Joy  

Microsoft Academic Search

This study largely investigates Alice Walker's fictions by focusing on the forms of art portrayed in her literature.Bsically, the diversity of arts illustrated in Alice Walker's books their roles in resurrecting female's identities , in general, are analyzed. It further scrutinizes the impact of art on the relationship of women and men including Celie, Shug, and Mr__; Mary Agnes and

Maryam Aminian

119

Project JXTA: A Loosely-Consistent DHT Rendezvous Walker Bernard Traversat, Mohamed Abdelaziz, Eric Pouyoul  

E-print Network

1 Project JXTA: A Loosely-Consistent DHT Rendezvous Walker Bernard Traversat, Mohamed Abdelaziz variety of decentralized network applications. The following paper describes a loosely- consistent DHT. The loosely-consistent DHT walker uses an hybrid approach that combines the use of a DHT to index and locate

Ricci, Laura

120

www.reading.ac.uk/meteoroloy www.walker-institute.ac.uk sbvbavpbafevjbafv  

E-print Network

and Climate? Classroom activity: The Richardson forecast factory Department of Meteorology and Walker Institute Resources for Schools The Department of Meteorology The Department of Meteorology was established: The Richardson forecast factory Department of Meteorology and Walker Institute Resources for Schools Results from

Hogan, Robin

121

Two American Entrepreneurs: Madame C. J. Walker and J. C. Penney. Teaching with Historic Places.  

ERIC Educational Resources Information Center

This lesson is based on the National Historic Landmark files, "Madame C. J. Walker Building" and "J. C. Penney Historic District," as well as other relevant sources. The lesson first discusses the Indianapolis (Indiana) site of Madame Walker's cosmetics business. The building is a 4-story brick structure completed in 1927. Another building built…

Koman, Rita

2000-01-01

122

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

Microsoft Academic Search

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.

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

2008-01-01

123

77 FR 67811 - Porter-Walker LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Energy Regulatory Commission [Docket No. ER13-327-000] Porter-Walker LLC; Supplemental Notice That Initial Market-Based...supplemental notice in the above-referenced proceeding of Porter-Walker LLC's application for market-based rate...

2012-11-14

124

GeoFrame Walker Lane: Overview, Rationale, and Objectives  

NASA Astrophysics Data System (ADS)

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.

Stockli, D. F.

2006-12-01

125

A case study on Walker-Warburg syndrome.  

PubMed

Walker-Warburg syndrome (WWS) is a rare, lethal genetic disease associated with a cobblestone-type lissencephaly, eye abnormalities, and a type of muscular dystrophy. There is a wide spectrum of brain and eye defects associated with this diagnosis; therefore, this diagnosis may not initially be considered. This diagnosis is especially difficult for families because there is no treatment available and management of the condition is supportive only. Parents of an infant with WWS need to be shown support and empathy while they are dealing with the sorrow of a terminal illness. Use of a nursing model, "Middle range theory of chronic sorrow," will be instrumental in assisting staff as they care for the patient and the patient's family. They also need to be guided toward receiving genetic counseling to weigh their options for future family planning as the risk of another WWS pregnancy is 25%. PMID:20150777

Kerr, Stephanie L

2010-02-01

126

Higgs effective potential in a perturbed Robertson-Walker background  

NASA Astrophysics Data System (ADS)

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 ? ? /? ?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.

Maroto, Antonio L.; Prada, Francisco

2014-12-01

127

The Walker circulation, diabatic heating, and outgoing longwave radiation  

NASA Astrophysics Data System (ADS)

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.

Stechmann, Samuel N.; Ogrosky, H. Reed

2014-12-01

128

Higgs effective potential in a perturbed Robertson-Walker background  

E-print Network

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.

Antonio L. Maroto; Francisco Prada

2014-12-15

129

Random Walker Ranking for NCAA Division I-A Football  

E-print Network

We develop a one-parameter family of ranking systems for NCAA Division I-A football teams based on a collection of voters, each with a single vote, executing independent random walks on a network defined by the teams (vertices) and the games played (edges). The virtue of this class of ranking systems lies in the simplicity of its explanation. We discuss the statistical properties of the randomly walking voters and relate them to the community structure of the underlying network. We compare the results of these rankings for recent seasons with Bowl Championship Series standings and component rankings. To better understand this ranking system, we also examine the asymptotic behaviors of the aggregate of walkers. Finally, we consider possible generalizations to this ranking algorithm.

Callaghan, T; Mucha, P J; Callaghan, Thomas; Porter, Mason A.; Mucha, Peter J.

2003-01-01

130

Late Holocene lake-level fluctuations in Walker Lake, Nevada, USA  

USGS Publications Warehouse

Walker Lake, a hydrologically closed, saline, and alkaline lake, is situated along the western margin of the Great Basin in Nevada of the western United States. Analyses of the magnetic susceptibility (??), total inorganic carbon (TIC), and oxygen isotopic composition (??18O) of carbonate sediments including ostracode shells (Limnocythere ceriotuberosa) from Walker Lake allow us to extend the sediment record of lake-level fluctuations back to 2700??years B.P. There are approximately five major stages over the course of the late Holocene hydrologic evolution in Walker Lake: an early lowstand (> 2400??years B.P.), a lake-filling period (??? 2400 to ??? 1000??years B.P.), a lake-level lowering period during the Medieval Warm Period (MWP) (??? 1000 to ??? 600??years B.P.), a relatively wet period (??? 600 to ??? 100??years B.P.), and the anthropogenically induced lake-level lowering period (< 100??years B.P.). The most pronounced lowstand of Walker Lake occurred at ??? 2400??years B.P., as indicated by the relatively high values of ??18O. This is generally in agreement with the previous lower resolution paleoclimate results from Walker Lake, but contrasts with the sediment records from adjacent Pyramid Lake and Siesta Lake. The pronounced lowstand suggests that the Walker River that fills Walker Lake may have partially diverted into the Carson Sink through the Adrian paleochannel between 2700 to 1400??years B.P. ?? 2006 Elsevier B.V. All rights reserved.

Yuan, F.; Linsley, B.K.; Howe, S.S.; Lund, S.P.; McGeehin, J.P.

2006-01-01

131

A review of the genus Monema Walker in China (Lepidoptera, Limacodidae)  

PubMed Central

Abstract Four species and one subspecies of the genus Monema Walker, 1855 are recognized from China, in which Monema tanaognatha Wu & Pan sp. n. is described as new, Monema coralina Dudgeon, 1895 and Monema meyi Solovyev & Witt, 2009 are newly recorded for China. The female of Monema meyi is reported for the first time. Monema nigrans de Joannis, 1901 and Monema melli Hering, 1931 are synonymized with Monema flavescens Walker, 1855. Cnidocampa rubriceps Matsumura, 1931 is regarded here as a subspecies of Monema flavescens Walker, 1855. The photographs of moths and their genitalia are given. A key to the species of the genus is provided. PMID:23794916

Pan, Zhaohui; Zhu, Chaodong; Wu, Chunsheng

2013-01-01

132

CH 302 10-11am MTWThF Spring 2012 Instructor Deb Walker  

E-print Network

of syllabus for info) #12;CH 302 10-11am MTWThF Spring 2012 Instructor Deb Walker Email Etiquette: When using proper etiquette could result in your email being ignored or overlooked. Homework: This course makes use

133

CH 301 8-9:30am TTh Spring 2012 Instructor D. Walker  

E-print Network

Instructor D. Walker TA: Matt Raiford Please see the syllabus posted on Blackboard for info. Email Etiquette to grades. Also include your version number when the email pertains to an exam. Ignoring proper etiquette

134

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

E-print Network

, Vulnerability, GIS #12;Walker, Figliozzi, Haire, and MacArthur 3 INTRODUCTION Our changing climate and response to its impacts will affect public life across a variety of sectors. Examples include agricultural changes

135

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 ...

136

ISS Update: Orion Recovery and Rescue Lead Tom Walker - Duration: 5:03.  

NASA Video Gallery

NASA Public Affairs Officer Brandi Dean talks with Tom Walker, Orion Recovery and Rescue Lead, about how the Neutral Buoyancy Laboratory (NBL) is being used to train rescue and recovery personnel f...

137

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

Code of Federal Regulations, 2014 CFR

...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)...

2014-04-01

138

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

Code of Federal Regulations, 2010 CFR

...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)...

2010-04-01

139

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

Code of Federal Regulations, 2011 CFR

...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)...

2011-04-01

140

The correlation functions of the XX Heisenberg magnet and random walks of vicious walkers  

E-print Network

A relationship of the random walks on one-dimensional periodic lattice and the correlation functions of the XX Heisenberg spin chain is investigated. The operator averages taken over the ferromagnetic state play a role of generating functions of the number of paths made by the so-called "vicious" random walkers (the vicious walkers annihilate each other provided they arrive at the same lattice site). It is shown that the two-point correlation function of spins, calculated over eigen-states of the XX magnet, can be interpreted as the generating function of paths made by a single walker in a medium characterized by a non-constant number of vicious neighbors. The answers are obtained for a number of paths made by the described walker from some fixed lattice site to another sufficiently remote one. Asymptotical estimates for the number of paths are provided in the limit, when the number of steps is increased.

N. M. Bogoliubov; C. Malyshev

2009-03-18

141

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

SciTech Connect

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.

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

142

Empirical Studies in Discourse Marilyn A. Walker \\Lambda & Johanna D. Moore y  

E-print Network

under investigation (Cohen, 1995; Sparck­Jones and Galliers, 1996; Walker, 1996). 1 The role­Jones and Galliers (1996, p.23) call features performance factors and distinguish between environmental factors which

Moore, Johanna D.

143

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

PubMed

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

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

2007-06-29

144

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

Code of Federal Regulations, 2013 CFR

...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) Identification. Cane, crutch,...

2013-04-01

145

Politics, aesthetics and diverse sexualities in the work of James Baldwin, Alice Walker and Toni Morrison   

E-print Network

The thesis investigates the ways in which James Baldwin, Alice Walker and Toni Morrison’s fictional portrayals of forms of love, eroticism and sexuality that are excluded or prohibited by social norms, destabilise ...

Sussman, Kathryn Judith

2011-07-01

146

Geomorphic Analysis Supporting Restoration of the Walker River, Nevada  

NASA Astrophysics Data System (ADS)

Agricultural water diversions have degraded the Walker River, Nevada, and have led to a reduction of water level at its terminus, Walker Lake. The geomorphic response of the river to water reallocation is an important issue associated with restoration of the system. To address this issue, we performed a geomorphic assessment of the portions of the river passing through the two main agricultural valleys in the watershed, Smith and Mason Valleys, Nevada. The project involved field data collection, analysis of remotely sensed data, and numerical modeling. Fieldwork focused primarily on characterizing bed and bank sediment grain size distributions and on delineating geomorphically similar reaches. The remote sensing analysis used LiDAR and air photograph mosaics from 1938, 1950, 1996, 1999, and 2006 to quantify historic changes in the active channel geometry and to identify banks that represent potential sediment sources or sinks. Polygons representing in-channel features (here defined as the scoured region between vegetation lines) were delineated by hand on each photograph. Channel centerlines were then derived from this data set and were used to identify locations of active channel movement by measuring either direct centerline offsets or local sinuosity increase rates. Both active bar area and channel migration were focused on reaches near the head of each agricultural valley, where slope decreases as the channel emerges from an upstream bedrock-controlled canyon. These same reaches also experienced large increases in width during the 1997 flood of record. The gage record shows that attenuation of this flood was most pronounced in the lower of the two agricultural valleys, Mason Valley. Surprisingly little attenuation occurred in the upstream Smith Valley, despite the relatively low relief of the valley floor, which consists primarily of Pleistocene lake deposits. The major difference between the two valleys is that the meander belt through Smith Valley is incised into the ancient lake bed, probably constraining flood flow to a much narrower region than in Mason Valley. In support of a reach scale morphodynamic model for the system, we estimated reach-average sediment exchange flux between eroding cut banks and new point bars. The estimates were derived from the overall rate of sinuosity increase for each subreach, rather than from simple lateral offset measurements which are sensitive to misalignment in the historic aerial photographs. Because bars are generally composed of coarser sediment than is typical for eroding cut banks, this exchange is probably associated with net storage of gravel in the floodplain. For several reaches in the dataset, lateral storage computed in this manner represents a significant fraction of bed material transport capacity.

Lauer, J. W.; Echterling, C.; Majerova, M.; Wilcock, P.

2012-12-01

147

A retrospective benefit-cost analysis of the 1997 stair-fall requirements for baby walkers  

Microsoft Academic Search

Based on estimates from the U.S. Consumer Product Safety Commission (CPSC), there were about 25,000 baby walker-related injuries treated annually in U.S. hospital emergency departments during the early 1990s. This amounted to about 8 injuries for every 1000 baby walkers in use. Most injuries resulted from falls down stairs. After CPSC initiated a regulatory proceeding in 1994, the CPSC staff

Gregory B. Rodgers; Elizabeth W. Leland

2008-01-01

148

Virtual slope control of a forward dynamic bipedal walker.  

PubMed

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

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

2005-02-01

149

Third annual Walker Branch Watershed research symposium. Program and abstracts  

SciTech Connect

The methods and concepts of watershed research, originally applied in an experimental or monitoring mode to relatively small catchments, are increasingly being used at larger scales and for specific applied problems. Research at Oak Ridge National Laboratory, the Tennessee Valley Authority, the US Forest Service, and other agencies and institutions participating in this symposium reflects research over a broad range of spatial scales that is being integrated through large-scale experiments along with computer modeling and graphical interfaces. These research projects address the basic atmospheric, geophysical, biogeochemical, and biological processes that regulate the responses of forested ecosystems to natural environmental variation and anthropogenic stresses. Regional and global issues addressed by presentations include emissions of carbon dioxide, methane, and other hydrocarbons; deposition of sulfate, nitrate, and mercury; land-use changes; biological diversity; droughts; and water quality. The reports presented in this symposium illustrate a wide range of methods and approaches and focus more on concepts and techniques than on a specific physical site. Sites and projects that have contributed research results to this symposium include Walker Branch Watershed (DOE), the Coweeta Hydrologic Laboratory and LTER site (USFS and NSF), Great Smoky Mountains National Park (research funded by NPS, TVA, and EPRI), Imnavait Creek, Alaska (DOE), the TVA-Norris Whole-tree Facility (TVA and EPRI), and DOE`s Biomass Program.

Not Available

1992-03-01

150

A jump persistent turning walker to model zebrafish locomotion.  

PubMed

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

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

2015-01-01

151

Field performance of the Walker Branch throughfall displacement experiment  

SciTech Connect

The authors are conducting a large-scale manipulative field experiments in an upland oak forest on the Walker Branch Watershed in eastern Tennessee USA to identify important ecosystem responses that might result from future precipitation changes. The manipulation of soil moisture is being implemented by a gravity-driven transfer of throughfall precipitation from one treatment plot to another. Throughfall is intercepted in {approx} 2,000 subcanopy troughs (0.3 x 5 m) suspended above the forest floor of the dry plots ({approx} 33% of the ground area is covered) and transferred by gravity flow across an ambient plot for subsequent distribution onto the wet treatment plot. Percent soil water is being monitored with time domain reflectometers at 310 sampling locations across the site. The experimental system is able to produce statistically significant differences in soil water content in years having both extremely dry and extremely wet conditions. Furthermore, comparisons of pre- and post-installation soil temperature measurements have documented the ability of the experimental design to produce these changes without changing the microclimate of the forest understory.

Hanson, P.J.; Todd, D.E.; Edwards, N.T.; Huston, M.A. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.

1994-10-06

152

A retrospective benefit-cost analysis of the 1997 stair-fall requirements for baby walkers.  

PubMed

Based on estimates from the U.S. Consumer Product Safety Commission (CPSC), there were about 25,000 baby walker-related injuries treated annually in U.S. hospital emergency departments during the early 1990s. This amounted to about 8 injuries for every 1000 baby walkers in use. Most injuries resulted from falls down stairs. After CPSC initiated a regulatory proceeding in 1994, the CPSC staff worked with industry to address the stair-fall hazard. This cooperative effort resulted in requirements designed to prevent stair-fall injuries that became effective in 1997 as part of a revised voluntary safety standard. This study presents a retrospective benefit-cost analysis of the 1997 stair-fall requirements. The benefits were defined as the reduction in the costs of injuries resulting from the use of the safer walkers. The costs were defined as the additional resource costs associated with making baby walkers safer. The study found that the stair-fall requirements were highly effective in reducing the risk of stair-fall injury, and that the benefits of the requirements substantially exceeded the costs. The expected net benefits (i.e., benefits minus costs) amounted to an average of about $169 per walker, over the walker's expected product life. Given current U.S. sales of about 600,000 baby walkers annually, the present value of the expected net benefits associated with 1 year's production amounts to over $100 million annually. A sensitivity analysis showed that the major findings were robust with respect to variations in underlying assumptions. PMID:18215533

Rodgers, Gregory B; Leland, Elizabeth W

2008-01-01

153

Electro-actuated hydrogel walkers with dual responsive legs.  

PubMed

Stimuli responsive polyelectrolyte hydrogels may be useful for soft robotics because of their ability to transform chemical energy into mechanical motion without the use of external mechanical input. Composed of soft and biocompatible materials, gel robots can easily bend and fold, interface and manipulate biological components and transport cargo in aqueous solutions. Electrical fields in aqueous solutions offer repeatable and controllable stimuli, which induce actuation by the re-distribution of ions in the system. Electrical fields applied to polyelectrolyte-doped gels submerged in ionic solution distribute the mobile ions asymmetrically to create osmotic pressure differences that swell and deform the gels. The sign of the fixed charges on the polyelectrolyte network determines the direction of bending, which we harness to control the motion of the gel legs in opposing directions as a response to electrical fields. We present and analyze a walking gel actuator comprised of cationic and anionic gel legs made of copolymer networks of acrylamide (AAm)/sodium acrylate (NaAc) and acrylamide/quaternized dimethylaminoethyl methacrylate (DMAEMA Q), respectively. The anionic and cationic legs were attached by electric field-promoted polyion complexation. We characterize the electro-actuated response of the sodium acrylate hydrogel as a function of charge density and external salt concentration. We demonstrate that "osmotically passive" fixed charges play an important role in controlling the bending magnitude of the gel networks. The gel walkers achieve unidirectional motion on flat elastomer substrates and exemplify a simple way to move and manipulate soft matter devices and robots in aqueous solutions. PMID:24651405

Morales, Daniel; Palleau, Etienne; Dickey, Michael D; Velev, Orlin D

2014-03-01

154

Design and Development of a Knee Mechanism for a Passive-Dynamic Walker  

NASA Astrophysics Data System (ADS)

Passive-dynamic walkers are mechanical devices that walk down a slope without being propelled by motors or controllers. In this paper we present the design of two different knee mechanisms intended for use with such walkers. At first we developed a knee mechanism that uses permanent magnets to lock the knee in the extended position and conducted walking experiments with a planar passive-dynamic walker, which was built beforehand. The walker moved down an incline and we counted the steps that it made. After performing several hundred trials we developed our second knee mechanism featuring an active release from the extended position and performed the same experiments with the same walker outfitted with the new mechanism. We compared the results achieved with the two different knee mechanisms. The active mechanism made an increased number of successful walks down the slope from which we concluded that it is more reliable and easier to use and set up than the one with permanent magnets.

Trifonov, Kalin; Hashimoto, Shuji

155

Does the Walker Lane extend through the Nevada test site region  

SciTech Connect

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.

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

1993-04-01

156

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

PubMed Central

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

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

2014-01-01

157

The fire-walker's high: affect and physiological responses in an extreme collective ritual.  

PubMed

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

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

2014-01-01

158

Corrections to the Walker-Thompson estimate of the cascade volume  

NASA Astrophysics Data System (ADS)

Sigmund [P. Sigmund, Appl. Phys. Lett. 25 (1974) 169] analytically predicted that the ratio of cascade volume to energy distribution volume should follow a universal curve that is sigmoidal in shape. Subsequent Monte Carlo simulations by Walker and Thompson [R.S. Walker, D.A. Thompson, Radiat. Eff. 37 (1978) 113] showed that although this curve is sigmoidal in shape, the curve is different for different materials with large deviations from Sigmund's prediction at high M2/ M1. Our analysis of the Walker and Thompson approach has revealed an error in the analytical equations used. A correct analysis of volume ratios using a different set of equations is presented. Analysis of data produced by SRIM [J.F. Ziegler, J.P. Biersack, U. Littmark, in: The Stopping and Range of Ions in solids, Pergamon, New York, 1985] (Monte Carlo) simulations gives results that are in good agreement with Sigmund's predictions.

Swaminarayan, S.; Nastasi, M.

2009-05-01

159

Diffusion-Limited Reactions and Mortal Random Walkers in Confined Geometries  

NASA Astrophysics Data System (ADS)

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.

Lohmar, Ingo; Krug, Joachim

2009-01-01

160

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

USGS Publications Warehouse

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.

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

1991-01-01

161

Test pilots 1962 - Armstrong, Walker, Dana, Peterson, McKay, Thompson, Butchart  

NASA Technical Reports Server (NTRS)

The research pilots at what in 1962 was called the Flight Research Center standing in front of the X-1E. They are (left to right) Neil Armstrong, Joe Walker, Bill Dana, Bruce Peterson, Jack McKay, Milt Thompson, and Stan Butchart. of the group, Armstrong, Walker, Dana, McKay and Thompson all flew the X-15. Bruce Peterson flew the M2-F2 and HL-10 lifting bodies, while Stan Butchart was the B-29 drop plane pilot for many of the D-558-II and X-1 series research aircraft.

1962-01-01

162

Fraction of uninfected walkers in the one-dimensional Potts model  

NASA Astrophysics Data System (ADS)

The dynamics of the one-dimensional q-state Potts model, in the zero-temperature limit, can be formulated through the motion of random walkers which either annihilate (A+A-->?) or coalesce (A+A-->A) with a q-dependent probability. We consider all of the walkers in this model to be mutually infectious. Whenever two walkers meet, they experience mutual contamination. Walkers which avoid an encounter with another random walker up to time t remain uninfected. The fraction of uninfected walkers is known to obey a power-law decay U(t)~t-?(q), with a nontrivial exponent ?(q) [C. Monthus, Phys. Rev. E 54, 4844 (1996); S. N. Majumdar and S. J. Cornell, ibid. 57, 3757 (1998)]. We probe the numerical values of ?(q) to a higher degree of accuracy than previous simulations and relate the exponent ?(q) to the persistence exponent ?(q) [B. Derrida, V. Hakim, and V. Pasquier, Phys. Rev. Lett. 75, 751 (1995)], through the relation ?(q)=?(q)?(q) where ? is an exponent introduced in [S. J. O'Donoghue and A. J. Bray, preceding paper, Phys. Rev. E 65, XXXX (2002)]. Our study is extended to include the coupled diffusion-limited reaction A+A-->B, B+B-->A in one dimension with equal initial densities of A and B particles. We find that the density of walkers decays in this model as ?(t)~t-1/2. The fraction of sites unvisited by either an A or a B particle is found to obey a power law, P(t)~t-? with ?~=1.33. We discuss these exponents within the context of the q-state Potts model and present numerical evidence that the fraction of walkers which remain uninfected decays as U(t)~t-?, where ?~=1.13 when infection occurs between like particles only, and ?~=1.93 when we also include cross-species contamination. We find that the relation between ? and ? in this model can also be characterized by an exponent ?, where similarly, ?=??.

O'Donoghue, S. J.; Bray, A. J.

2002-05-01

163

Presence of dynorphin-like immunoreactivity but not opiate binding in Walker-256 tumors  

SciTech Connect

Walker-256 tumor tissue was removed from rats on day 8 of tumor growth. An acidified methanol extract of the tumor tissue was assayed for immunoreactive (ir) dynorphin-A 1-17 (DYN-17) and ir-dynorphin-A (DYN-8). Levels of ir-DYN-17 and ir-DYN-8 were nearly 4- and 8-fold higher, respectively, in tumors versus normal muscle. However, tumor homogenates did not exhibit specific /sup 3/H-naloxone binding. These results indicate that although the Walker-256 carcinosarcoma may produce opioids, it is unlikely that these ectopic substances have direct opioid actions on the tumor itself. 34 references, 1 figure.

Bryant, H.U.; Conroy, W.G.; Isom, G.E.; Malven, P.V.; Yim, G.K.W.

1985-07-15

164

A 1200 year record of hydrologic variability in the Sierra Nevada from sediments in Walker Lake, Nevada  

E-print Network

A 1200 year record of hydrologic variability in the Sierra Nevada from sediments in Walker Lake, Nevada Fasong Yuan Department of Earth and Atmospheric Sciences, University at Albany-State University) fraction from cored sediments of Walker Lake, Nevada, were conducted at an average resolution of $3 years

Linsley, Braddock K.

165

INTEGER HULLS OF LINEAR POLYHEDRA AND SCL IN DANNY CALEGARI AND ALDEN WALKER  

E-print Network

INTEGER HULLS OF LINEAR POLYHEDRA AND SCL IN FAMILIES DANNY CALEGARI AND ALDEN WALKER Abstract. The integer hull of a polyhedron is the convex hull of the inte- ger points contained in it. We show that the vertices of the integer hulls of a rational family of polyhedra of size O(n) have eventually

McReynolds, Ben

166

A Linguistic Analysis of Rhetorical Strategies in Selected Narratives of Alice Walker  

ERIC Educational Resources Information Center

The objective of this investigation was to analyze rhetorical strategies of Alice Walker in four narratives, namely, "The Color Purple, In Search of Our Mother's Gardens, Possessing the Secret of Joy, and Now Is the Time To Open Your Heart". As such, this study helps to expand the body of investigation relating linguistics to literature and medium…

Matunda, Robert Stephen Mokaya

2009-01-01

167

Summer 2010 BOSTONIA 19PHOTOGRAPHS BY MELODY KOMYEROV WERE THE FIRST HUMANS WALKERS OR TREE  

E-print Network

Anthropologist Jeremy DeSilva, holding the right foot of a human (top) and of a chimpanzee (bottom), filmed wild, or humans, and tries to draw conclusions about how those early animals moved. "My initial inquirySummer 2010 BOSTONIA 19PHOTOGRAPHS BY MELODY KOMYEROV WERE THE FIRST HUMANS WALKERS OR TREE

Goldberg, Bennett

168

Mechanical Hip Actuation Of A 2-D Passive-Dynamics Based Walker  

E-print Network

Mechanical Hip Actuation Of A 2-D Passive-Dynamics Based Walker TAM 492 ­ 3 Credits Matt Strasberg is to take advantage of the passive dynamical properties of the robot so as to reduce energy used. By using trials to produce a small number of short walks.2 We seek to build a simple, slightly powered passive

Ruina, Andy L.

169

SUPPORTING ONLINE MATERIAL Efficient bipedal robots based on passive-dynamic walkers  

E-print Network

SUPPORTING ONLINE MATERIAL for Efficient bipedal robots based on passive-dynamic walkers Steve learning biped. This movie begins with the powered robot imitating passive walking down a 0.9 degree slope important to the passive dynamics of the system. The hip joint is fully passive. A latch at each knee

Tedrake, Russ

170

SUPPORTING ONLINE MATERIAL Efficient bipedal robots based on passive-dynamic walkers  

E-print Network

SUPPORTING ONLINE MATERIAL for Efficient bipedal robots based on passive-dynamic walkers Steven H learning biped. This movie begins with the powered robot imitating passive walking down a 0.9 degree slope important to the passive dynamics of the system. The hip joint is fully passive. A latch at each knee

Collins, Steven H.

171

Variability in the Length and Frequency of Steps of Sighted and Visually Impaired Walkers  

ERIC Educational Resources Information Center

The variability of the length and frequency of steps was measured in sighted and visually impaired walkers at three different paces. The variability was low, especially at the preferred pace, and similar for both groups. A model incorporating step counts and step frequency provides good estimates of the distance traveled. Applications to…

Mason, Sarah J.; Legge, Gordon E.; Kallie, Christopher S.

2005-01-01

172

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

ERIC Educational Resources Information Center

"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…

Bahr, Kathy

2010-01-01

173

Statement of Facts for 1977 City-Wide Mock Trial Competitions. Walker Thomas v. Sam Nomad.  

ERIC Educational Resources Information Center

Prepared by the District of Columbia Street Law Project for its annual city-wide mock trial competition, this instructional handout provides material for a civil case over an automobile accident. Walker Thomas is suing Sam Nomad for damages that resulted from a collision, for which both parties blame the other. The handout clarifies the laws and…

National Inst. for Citizen Education in the Law, Washington, DC.

174

Ventilation Requirements in Hot Humid Iain S. Walker and Max H. Sherman  

E-print Network

LBNL-59889 Ventilation Requirements in Hot Humid Climates Iain S. Walker and Max H. Sherman residential ventilation standard, ASHRAE Standard 62.2. Meeting this standard in new construction requires the use of mechanical ventilation, which in turn can often significantly increase the latent load faced

175

Growth by random walker sampling and scaling of the dielectric breakdown model  

Microsoft Academic Search

Random walkers absorbing on a boundary sample the harmonic measure linearly and independently: we discuss how the recurrence times between impacts enable nonlinear moments of the measure to be estimated. From this we derive a technique to simulate dielectric breakdown model growth, which is governed nonlinearly by the harmonic measure. For diffusion-limited aggregation, recurrence times are shown to be accurate

Ellák Somfai; Nicholas R. Goold; Robin C. Ball; Jason P. Devita; Leonard M. Sander

2004-01-01

176

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

ERIC Educational Resources Information Center

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…

SHW Group, Inc., Dallas, TX.

177

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

Microsoft Academic Search

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

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

178

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

Microsoft Academic Search

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

J. M. S. Pearce

2005-01-01

179

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

E-print Network

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 ...

Baines, Andrew Griffin

2005-01-01

180

Shape optimization of peristaltic pumping Shawn W. Walker *, Michael J. Shelley  

E-print Network

Shape optimization of peristaltic pumping Shawn W. Walker *, Michael J. Shelley New York University 14 October 2009 Available online 25 October 2009 Keywords: Peristalsis Pumping Shape optimization PDE of biology and peristaltic pumping is a fundamental mechanism to accomplish this; it is also important

Shelley, Michael

181

A Test of Amino Acid Reversibility Nick G.C. Smith, Adam Eyre-Walker  

E-print Network

A Test of Amino Acid Reversibility Nick G.C. Smith, Adam Eyre-Walker Centre for the Study no evidence to reject the assumption of reversibility in protein evolution. Key words: Amino acid evolution the evolution of proteins, it is generally assumed that the number of substitutions from amino acid X to amino

Eyre-Walker, Adam

182

Recent multidecadal strengthening of the Walker circulation across the tropical Pacific  

NASA Astrophysics Data System (ADS)

The Pacific Walker circulation is a large overturning cell that spans the tropical Pacific Ocean, characterized by rising motion (lower sea-level pressure) over Indonesia and sinking motion (higher sea level-pressure) over the eastern Pacific. Fluctuations in the Walker circulation reflect changes in the location and strength of tropical heating, so related circulation anomalies have global impacts. On interannual timescales, the El Niño/Southern Oscillation accounts for much of the variability in the Walker circulation, but there is considerable interest in longer-term trends and their drivers, including anthropogenic climate change. Here, we examine sea-level pressure trends in ten different data sets drawn from reanalysis, reconstructions and in situ measurements for 1900-2011. We show that periods with fewer in situ measurements result in lower signal-to-noise ratios, making assessments of sea-level pressure trends largely unsuitable before about the 1950s. Multidecadal trends evaluated since 1950 reveal statistically significant, negative values over the Indonesian region, with weaker, positive trends over the eastern Pacific. The overall trend towards a stronger, La Niña-like Walker circulation is nearly concurrent with the observed increase in global average temperatures, thereby justifying closer scrutiny of how the Pacific climate system has changed in the historical record.

L'Heureux, Michelle L.; Lee, Sukyoung; Lyon, Bradfield

2013-06-01

183

From a ‘blind walker’ to an ‘urban curator’: initiating ‘emotionally moving situations’ in public spaces  

Microsoft Academic Search

Reconstructing the mutation of a ‘blind walker’ into the figure of reflexive urban activist, who proposes creative solutions to the problems of de-activated public spaces, urban art interventions are comprehended as a tool for re-inventing and revitalising urban settings while initiating intensive interaction and cooperation between citizens. The idea to arrange ‘emotionally moving situations’ so as to activate reflexive attitude

Jekaterina Lavrinec

2011-01-01

184

Writing a Rationale for a Controversial Common Reading Book: Alice Walker's "The Color Purple."  

ERIC Educational Resources Information Center

Offers a rationale that can be used to defend the assignment of Alice Walker's controversial novel for class reading. Indicates four issues that might evoke calls for censorship: (1) subject matter, (2) vocabulary, (3) grammar, and (4) the epistolary form of the work. (RBW)

Worthington, Pepper

1985-01-01

185

Dynamics with Infinitely Many Time Derivatives in Friedmann-Robertson-Walker Background and Rolling Tachyon  

E-print Network

Open string field theory in the level truncation approximation is considered. It is shown that the energy conservation law determines existence of rolling tachyon solution. The coupling of the open string field theory action to a Friedmann-Robertson-Walker metric is considered which leads to a new time dependent rolling tachyon solution is presented and possible cosmological consequences are discussed.

Liudmila Joukovskaya

2008-07-14

186

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

Microsoft Academic Search

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.

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

2003-01-01

187

Determination of Gas Exchange Rate Constants for a Small Stream on Walker Branch Watershed, Tennessee  

Microsoft Academic Search

The steady state tracer gas method was used to determine gas exchange rate constants (k) for a small stream (annual average flow <=1 m3\\/min) draining the West Fork of Walker Branch watershed in eastern Tennessee. Chloride was used as a conservative tracer to account for dilution by lateral inflow, and propane and ethane were used as volatile tracers. Gas exchange

David P. Genereux; Harold F. Hemond

1992-01-01

188

Determination of gas exchange rate constants for a small stream on Walker Branch Watershed, Tennessee  

Microsoft Academic Search

The steady state tracer gas method was used to determine gas exchange rate constants (k) for a small stream (annual average flow ?1 m3\\/min) draining the West Fork of Walker Branch watershed in eastern Tennessee. Chloride was used as a conservative tracer to account for dilution by lateral inflow, and propane and ethane were used as volatile tracers. Gas exchange

David P. Genereux; Harold F. Hemond

1992-01-01

189

Hall Thruster Cluster Operation with a Shared Cathode Mitchell L. R. Walker  

E-print Network

Hall Thruster Cluster Operation with a Shared Cathode Mitchell L. R. Walker and Alec D. Gallimore on the performance of a 2 1 cluster of 5-kW Hall effect thrusters are investigated. The cluster is operated from 1 centerline on the performance of a 5-kW Hall effect thruster are investigated. The data show that the cathode

Walker, Mitchell

190

Variables of the Touch Technique that Influence the Safety of Cane Walkers  

ERIC Educational Resources Information Center

This study evaluated variables that determined the safety of 15 cane users who were using the touch technique. The results showed that none of the walkers used a touch technique as described and recommended in the literature, that the detection of obstacles was related mainly to the height of the cane tip during the sweep, and that the early…

Bongers, Raoul M.; Schellingerhout, Roelef; van Grinswen, Roland; Smitsman, Ad W.

2002-01-01

191

Spatial audio in small screen device displays Ashley Walker and Stephen Brewster  

E-print Network

Spatial audio in small screen device displays Ashley Walker and Stephen Brewster Department:ashley,stephen@dcs.gla.ac.uk keywords: interface design, 3D audio, delay affordance, usability testing Our work addresses problem of techniques - from the graphical to the audio domain - for exploiting space in information representation

Williamson, John

192

Guide to the Papers in the John Hunter Walker Collection, 1911-1953.  

ERIC Educational Resources Information Center

This guide to the papers of John Hunter Walker (1872-1955) which are housed in the Illinois Historical Survey Library includes a biographical sketch of this prominent Illinois labor leader and key figure in both the Illinois State Federation of Labor and the United Mine Workers of America; an organizational statement explaining the acquisition of…

Carlson, Douglas W.; And Others

193

Sleep-Dependent Memory Processing Matthew P. Walker, PhD  

E-print Network

REVIEW Sleep-Dependent Memory Processing Matthew P. Walker, PhD While the functions of sleep remain largely unknown, one exciting hypothesis is that sleep contributes importantly to processes of memory supporting this role of sleep in what is becoming known as sleep- dependent memory processing. This review

Walker, Matthew P.

194

PREFERENCES FOR INTERFACE DESIGN FOR A NAVIGATION ASSISTANT ON A WHEELED WALKER  

E-print Network

by a variety of dementing disorders including Alzheimer's disease (AD) [5], Parkinson's disease, and multiple sclerosis [6]. Among individuals with the most common of these disorders, dementia of the Alzheimer type on walkers are currently in development, including the Personal Aid for Mobility and Monitoring (PAMM) [9

Kulyukin, Vladimir

195

Origin of the Pinenuts and Other Stories from the Walker River Paiute Reservation.  

ERIC Educational Resources Information Center

The four stories gathered from Paiute Tribal Elders through the Ethnic Heritage Studies Program have been changed from the original telling insofar as it was necessary to make them suitable to the elementary level. The short stories, meant to be spoken orally, relate how the Walker Lake Paiutes got pinenuts away from the Owyhee area ("Origin of…

George, Wuzzie; And Others

196

Coinfection with Multiple Tick-Borne Pathogens in a Walker Hound Kennel in North Carolina  

Microsoft Academic Search

Both dogs and humans can be coinfected with various Ehrlichia, Bartonella, Rickettsia, and Babesia species. We investigated a kennel of sick Walker Hounds and their owners in southeastern North Carolina for evidence of tick-borne infections and associated risk factors. A high degree of coinfection was documented in the dog population. Of the 27 dogs, 26 were seroreactive to an Ehrlichia

S. K. KORDICK; E. B. BREITSCHWERDT; B. C. HEGARTY; K. L. SOUTHWICK; C. M. COLITZ; S. I. HANCOCK; J. M. BRADLEY; R. RUMBOUGH; J. T. MCPHERSON

1999-01-01

197

Efficient Computation of Cosmic Microwave Background Anisotropies in Closed Friedmann-Robertson-Walker Models  

Microsoft Academic Search

We implement the efficient line-of-sight method to calculate the anisotropy and polarization of the cosmic microwave background for scalar and tensor modes in almost Friedmann-Robertson-Walker models with positive spatial curvature. We present new results for the polarization power spectra in such models.

Antony Lewis; Anthony Challinor; Anthony Lasenby

2000-01-01

198

Job submission to grid computing environments RP Bruin, TOH White, AM Walker, KF Austen, MT Dove  

E-print Network

Job submission to grid computing environments RP Bruin, TOH White, AM Walker, KF Austen, MT Dove Albemarle Street, London W1S 4BS Abstract The problem of enabling scientist users to submit jobs to grid scientists to work with raw Globus job-submission commands ­ in the end they are likely to end up

Cambridge, University of

199

A gait stability investigation into FES-assisted paraplegic walking based on the walker tipping index  

NASA Astrophysics Data System (ADS)

The gait outcome measures used in clinical trials of paraplegic locomotor training determine the effectiveness of improved walking function assisted by the functional electrical stimulation (FES) system. Focused on kinematic, kinetic or physiological changes of paraplegic patients, traditional methods cannot quantify the walking stability or identify the unstable factors of gait in real time. Up until now, the published studies on dynamic gait stability for the effective use of FES have been limited. In this paper, the walker tipping index (WTI) was used to analyze and process gait stability in FES-assisted paraplegic walking. The main instrument was a specialized walker dynamometer system based on a multi-channel strain-gauge bridge network fixed on the frame of the walker. This system collected force information for the handle reaction vector between the patient's upper extremities and the walker during the walking process; the information was then converted into walker tipping index data, which is an evaluation indicator of the patient's walking stability. To demonstrate the potential usefulness of WTI in gait analysis, a preliminary clinical trial was conducted with seven paraplegic patients who were undergoing FES-assisted walking training and seven normal control subjects. The gait stability levels were quantified for these patients under different stimulation patterns and controls under normal walking with knee-immobilization through WTI analysis. The results showed that the walking stability in the FES-assisted paraplegic group was worse than that in the control subject group, with the primary concern being in the anterior-posterior plane. This new technique is practical for distinguishing useful gait information from the viewpoint of stability, and may be further applied in FES-assisted paraplegic walking rehabilitation.

Ming, Dong; Bai, Yanru; Liu, Xiuyun; Qi, Hongzhi; Cheng, Longlong; Wan, Baikun; Hu, Yong; Wong, Yatwa; Luk, Keith D. K.; Leong, John C. Y.

2009-12-01

200

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

USGS Publications Warehouse

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

Jayko, Angela S.; Bursik, Marcus

2012-01-01

201

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

NASA Astrophysics Data System (ADS)

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

Pier, Jeffrey R.; Mason, Brian

2005-12-01

202

Coexistance of cerebral sinovenous thrombosis and Dandy Walker malformation in newborn.  

PubMed

Cerebral sinovenous thrombosis in neonatal period may cause neurological impairment, epilepsy, and lead to stroke. It is caused primarily by coagulopathy of numerous reasons, occasionally perinatal asphyxia, traumatic delivery and hyperhomocysteinemia. Dandy-Walker malformation is characterized by agenesis or hypoplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle, and enlargement of the posterior fossa. Dandy-Walker malformation, variant, and mega cisterna magna represent a spectrum of developmental anomalies. Insults to developing cerebellar hemispheres and the fourth ventricle are believed to be the cause of malformation. Our patient was born from noncomplicated pregnancy, noncomplicated nontraumatic vaginal delivery at term, excellent Apgar scores, without peculiarities in clinical status. She was brest-fed by the 42nd hour of life when she had rightsided seizures during sleep that repeated for five times in next 24 hours. Brain Ultrasound (US) revealed clot in left lateral ventricle, slight dilatation of left ventricle, both sided periventricular echodensity, ischemia, slight enlargement of forth ventricle and a bit smaller cerebellum. There was no visible flow through left transverse, superior sagittal and straight sinus. Magnetic Resonance (MRI) confirmed the finding and showed thrombosis of left and right transverse venous sinuses and confluence of sinuses. Electroencephalogram (EEG) showed leftsided focal changes. The newborn was treated with phenobarbiton for 8 days and had no convulsions during that period. All coagulation parameters, homocistein, lipoproteins (a) and D-dimers were normal. There were no mutations on FV R506Q, PT 20210A, MTHFR 677C/T. No antiphospholipides were found. Heart US showed no structural anomalies. No other patology or risk factors were present at the time. Before discharge, US showed hydrocephalus. Flow in affected sinuses was visible with color Doppler. MRI showed recanalization of affected sinuses, also hydrocephalus and presentation of Dandy Walker On EEG there was borderline finding. Due to progression of hydrocephalus ventriculo-peritoneal shunt was placed. In age of 1 year EEG was slower for age but without focus. Neurological development was normal for age. The question is whether this child had intrauterine insult and inception of Dandy Walker with further postnatal progress of thrombosis and evolution to full picture of Dandy Walker with hydrocephalus OR thrombosis that led to development of hydrocephalus and Dandy Walker malformation in this child were accidental coexistance. PMID:21648352

Gveri?-Ahmetasevi?, Snjezana; Coli?, Ana; Gveri?, Tugomir; Gasparovi?, Vesna Elvedi; Pavlisa, Goran; Ozreti?, David

2011-01-01

203

A comparison of gait characteristics in the elderly people, people with knee pain, and people who are walker dependent people.  

PubMed

[Purpose] The purpose of this study was to compare the gait parameters of age-matched people with a normal gait (? 65?years), age-matched people with knee pain, and age-matched people with walker dependent gait at a self-selected gait speed. [Methods] Subjects walked on even ground in bare feet and were allowed a natural arm swing on a 6-m walkway. Walker-dependent participants walked on a walkway without a walker. [Results] The kinematic and spatiotemporal gait characteristics were used to investigate the difference among the each group. Hip flexion, knee flexion, and stride width parameters were not different. The gait speed, stride length and time, hip and knee extension, and ankle flexion and extension parameters were significantly different. [Conclusion] A comparision of kinematic and spatiotemporal gait characteristics during gait may provide an insight into the gait pattern of normal elderly people, those with knee pain, and the walker-dependent elderly. PMID:24259896

Lee, In-Hee; Park, Sang-Young

2013-08-01

204

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

E-print Network

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.

R J Wiltshire

2003-02-12

205

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

206

Jones-Hedman walker modification for C7 quadriplegic patient: case study in team cooperation.  

PubMed

A 20-year-old man with C7 quadriplegia was admitted to a tertiary care rehabilitation facility 1.5 months after discharge from an acute care community hospital. The patient's goals were to improve his skills in activities of daily living to a level of maximum independence, and to walk. Although his high level of spinal cord injury made ambulation unlikely, an occupational therapist and a rehabilitation engineer, working together, devised a method to help the patient meet his ambulation goal. They modified an ordinary walker by fabricating polyvinyl chloride-acrylic alloy guards lined with foam to reduce palmar pressure. The patient was then able to use wrist and finger extension during walker advancement and was able to ambulate 300m with Craig-Scott orthosis. The case illustrates the importance of a skilled interdisciplinary team in a specialized center for management of spinal cord injured patients. PMID:3942487

Yarkony, G M; Jones, R; Hedman, G; O'Donnell, A

1986-01-01

207

Birth of a fault: Connecting the Kern County and Walker Pass, California, earthquakes  

USGS Publications Warehouse

A band of seismicity transects the southern Sierra Nevada range between the northeastern end of the site of the 1952 MW (moment magnitude) 7.3 Kern County earthquake and the site of the 1946 MW 6.1 Walker Pass earthquake. Relocated earthquakes in this band, which lacks a surface expression, better delineate the northeast-trending seismic lineament and resolve complex structure near the Walker Pass mainshock. Left-lateral earthquake focal planes are rotated counterclockwise from the strike of the seismic lineament, consistent with slip on shear fractures such as those observed in the early stages of fault development in laboratory experiments. We interpret this seismic lineament as a previously unrecognized, incipient, currently blind, strike-slip fault, a unique example of a newly forming structure.

Bawden, G.W.; Michael, A.J.; Kellogg, L.H.

1999-01-01

208

Hidden marker position estimation during sit-to-stand with walker.  

PubMed

Motion capture analysis of sit-to-stand task with assistive device is hard to achieve due to obstruction on reflective makers. Previously developed robotic system, Smart Mobile Walker, is used as an assistive device to perform motion capture analysis in sit-to-stand task. All lower limb markers except hip markers are invisible through whole session. The link-segment and regression method is applied to estimate the marker position during sit-to-stand. Applying a new method, the lost marker positions are restored and the biomechanical evaluation of the sit-to-stand movement with a Smart Mobile Walker could be carried out. The accuracy of the marker position estimation is verified with normal sit-to-stand data from more than 30 clinical trials. Moreover, further research on improving the link segment and regression method is addressed. PMID:23366295

Yoon, Sang Ho; Jun, Hong Gul; Dan, Byung Ju; Jo, Byeong Rim; Min, Byung Hoon

2012-01-01

209

Schizophrenia-Like Psychosis and Dandy-Walker Variant Comorbidity: Case Report  

PubMed Central

Dandy-Walker variant is a developmental malformation consisting of cerebellar hypoplasia and cystic dilatation of the fourth ventricle. Previous research has proposed a possible role for the cerebellum in cognition and in schizophrenia. In this paper we report a schizophrenia-like psychotic disorder in a 30 year-old woman with Dandy-Walker variant. The patient was treated with risperidone 6 mg/day, biperiden 4 mg/day and risperidone depot 50 mg injections fortnightly, and most of the symptoms were ameliorated within 2 months. The similar cognitive profile to populations with cerebellar pathology and rarity of the condition strongly suggests that there may be direct relationship between cerebellar pathology and appearence of psychotic symptoms. PMID:24605131

K?v?lc?m, Yi?it; ?zci, Filiz; Semiz, Umit Basar

2014-01-01

210

Growth by random walker sampling and scaling of the dielectric breakdown model  

Microsoft Academic Search

Random walkers absorbing on a boundary sample the Harmonic Measure linearly\\u000aand independently: we discuss how the recurrence times between impacts enable\\u000anon-linear moments of the measure to be estimated. From this we derive a new\\u000atechnique to simulate Dielectric Breakdown Model growth which is governed\\u000anonlinearly by the Harmonic Measure. Recurrence times are shown to be accurate\\u000aand effective

Ellák Somfai; Nicholas R. Goold; Robin C. Ball; Jason P. DeVita; Leonard M. Sander

2004-01-01

211

Matching of Friedmann-Lemaitre-Robertson-Walker and Kantowski-Sachs cosmologies.  

NASA Astrophysics Data System (ADS)

The matching of Friedmann-Lemaître-Robertson-Walker (FLRW) space-times onto Kantowski-Sachs space-times with strings is investigated. Employing Darmois junction conditions, a spherically symmetric homogeneous anisotropic Kantowski-Sachs metric with strings can be joined smoothly to the present day universe represented by FLRW space-times. This cosmological model is expected to be an important tool for studying the early stage of the universe.

Borgohain, P.; Patgiri, M.

1998-07-01

212

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

Microsoft Academic Search

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

ARTHUR H. KEENEYJ; Virginia T. Keeney

1997-01-01

213

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

PubMed

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

Keeney, A H; Keeney, V T

1997-01-01

214

Short term mating strategies and attraction to masculinity in point-light walkers  

Microsoft Academic Search

pStrategic pluralism suggests that women engage in short-term sexual relationships when the benefits to doing so outweigh the costs. We investigated attraction to indicators of good genes (namely, masculinity as demonstrated by point-light walkers) in women varying in menstrual cycle status and sociosexual orientation. When women are fertile, they have the ability to gain genetic benefits from a male partner

Meghan P. Provost; Nikolaus F. Troje; Vernon L. Quinsey

2008-01-01

215

Spacelike hypersurfaces of constant higher order mean curvature in generalized Robertson-Walker spacetimes  

E-print Network

In this paper we analyze the problem of uniqueness for spacelike hypersurfaces with constant higher order mean curvature in generalized Robertson-Walker spacetimes. We consider first the case of compact spacelike hypersurfaces, completing some previous results given in [2]. We next extend these results to the complete noncompact case. In that case, our approach is based on the use of a generalized version of the Omori-Yau maximum principle for trace type differential operators, recently given in [3].

Alias, Luis J; Rigoli, Marco

2011-01-01

216

Sex pheromone components of the spring hemlock looper, Lambdina athasaria (Walker) (Lepidoptera: Geometridae)  

Microsoft Academic Search

Two methylated hydrocarbons, 7-methylheptadecane (7) and 7,11-dimethylheptadecane (7,11), are female sex pheromone components of the spring hemlock looper (SHL),Lambdina athasaria (Walker). Compounds extracted from female pheromone glands were identified by coupled gas chromatographic-electroantennographic detection (GC-EAD) and coupled GC-mass spectrometry (GC-MS) in selected ion monitoring mode. In field trapping experiments, (7) and (7,11) by themselves were behaviorally inactive, but in combination

Regine Gries; Gerhard Gries; Jianxiong Li; Chris T. Maier; Carol R. Lemmon; Keith N. Slessor

1994-01-01

217

Quantum evolution of scalar fields in Robertson-Walker space-time  

E-print Network

We study the $\\lambda \\phi^4$ field theory in a flat Robertson-Walker space-time using the functional Sch\\"odinger picture. We introduce a simple Gaussian approximation to analyze the time evolution of pure states and we establish the renormalizability of the approximation. We also show that the energy-momentum tensor in this approximation is finite once we consider the usual mass and coupling constant renormalizations.

O. J. P. Eboli; H. C. Reis

1995-10-10

218

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

ERIC Educational Resources Information Center

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…

Huber, Germaine W.

2009-01-01

219

Covariant and quasi-covariant quantum dynamics in Robertson-Walker spacetimes  

NASA Astrophysics Data System (ADS)

We propose a canonical description of the dynamics of quantum systems on a class of Robertson-Walker spacetimes. We show that the worldline of an observer in such spacetimes determines a unique orbit in the identity component SO0(4, 1) of the local conformal group of the spacetime and that this orbit determines a unique transport on the spacetime. For a quantum system on the spacetime modelled by a net of local algebras, the associated dynamics is expressed via a suitable family of 'propagators'. In the best of situations, this dynamics is covariant, but more typically the dynamics will be 'quasi-covariant' in a sense we make precise. We then show, by using our technique of 'transplanting' states and nets of local algebras from de Sitter space to Robertson-Walker space, that there exist quantum systems on Robertson-Walker spaces with quasi-covariant dynamics. The transplanted state is locally passive, in an appropriate sense, with respect to this dynamics.

Buchholz, Detlev; Mund, Jens; Summers, Stephen J.

2002-12-01

220

Test pilots 1962 - Thompson, McKay, Dana, Armstrong, Peterson, Butchart, Walker  

NASA Technical Reports Server (NTRS)

A group photo of NASA research pilots at the front door of the Flight Research Center headquarters building. In the front row are (left to right) Milt Thompson, Jack McKay, and Bill Dana. All three flew the X-15, and Thompson and Dana were also involved in the lifting body flights. McKay was injured in a crash landing in X-15 #2. Although he recovered, the injuries eventually forced him to retire from research flying. In the back row (left to right) are Neil Armstrong, Bruce Peterson, Stanley Butchart, and Joe Walker. Armstrong and Walker also both flew the X-15. Soon after this photo was taken, Armstrong was selected as an astronaut, and seven years later became the first man to walk on the Moon. Walker made the highest flight in the X-15, reaching 354,200 feet. He then went on to fly the Lunar Landing Research Vehicle, and was killed on June 8, 1966 when his F-104N collided with the XB-70. Peterson made the first flight in the HL-10 lifting body, and was later badly injured in the crash of the M2-F2 lifting body. Butchart flew a wide range of research missions in the 1950s, and was the B-29 drop plane pilot for a number of rocket flight.

1962-01-01

221

Optimal covariant fitting to a Robertson-Walker metric and smallness of backreaction  

E-print Network

We define a class of "optimal" coordinate systems by requiring that the deviation from an exact Robertson-Walker metric is "as small as possible" within a given four dimensional volume. The optimization is performed by minimizing several volume integrals which would vanish for an exact Robertson-Walker metric. Covariance is automatic. Foliation of space-time is part of the optimization procedure. Only the metric is involved in the procedure, no assumptions about the origin of the energy-momentum tensor are needed. A scale factor does not show up during the optimization process, the optimal scale factor is determined at the end. The general formulation is non perturbative. An explicit perturbative treatment is possible. The shifts which lead to the optimal coordinates obey Euler-Lagrange equations which are formulated and solved in first order of the perturbation. The extension to second order is sketched, but turns out to be unnecessary. The only freedom in the choice of coordinates which finally remains are the rigid transformations which keep the form of the Robertson-Walker metric intact, i.e. translations in space and time, spatial rotations, and spatial scaling. Spatial averaging becomes trivial. In first order of the perturbation there is no backreaction. A simplified second order treatment results in a very small effect, excluding the possibility to mimic dark energy from backreaction. This confirms (as well as contradicts) statements in the literature.

Dieter Gromes

2011-11-24

222

The influence of ENSO on the equatorial Atlantic precipitation through the Walker circulation in a CGCM  

NASA Astrophysics Data System (ADS)

The link between El Niño/Southern Oscillation (ENSO) and the equatorial Atlantic precipitation during boreal spring (March-April-May) is explored using a coupled general circulation model (CGCM). Interannual variability of the equatorial Atlantic sea surface temperature (SST) in the CGCM is excluded by nudging the modeled SST toward the climatological monthly mean of observed SST in the equatorial Atlantic, but full air-sea coupling is allowed elsewhere. It is found that the equatorial Atlantic precipitation is reduced (increased) during El Niño (La Niña) in the case where the interannual variability of the equatorial Atlantic SST is disabled. The precipitation anomalies in the equatorial Atlantic during ENSO are not strongly associated with the meridional migration of the Atlantic inter-tropical convergence zone. We find the reduced precipitation in the equatorial Atlantic during El Niño is associated with an enhanced Atlantic Walker circulation characterized by strengthened low-level easterlies and anomalous dry, downward winds over the equatorial Atlantic, while the Pacific Walker circulation is weakened. The upper-level anomalous westerlies over the equatorial Atlantic are consistent with a Matsuno-Gill-type response to heating in the eastern equatorial Pacific. Our results of the CGCM experiments suggest that changes to the Walker circulation induced by ENSO contribute significantly to changes in precipitation over the equatorial Atlantic.

Sasaki, Wataru; Doi, Takeshi; Richards, Kelvin J.; Masumoto, Yukio

2015-01-01

223

Equatorial Pacific coral geochemical records show recent weakening of the Walker Circulation  

NASA Astrophysics Data System (ADS)

Equatorial Pacific ocean-atmosphere interactions affect climate globally, and a key component of the coupled system is the Walker Circulation, which is driven by sea surface temperature (SST) gradients across the equatorial Pacific. There is conflicting evidence as to whether the SST gradient and Walker Circulation have strengthened or weakened over the late twentieth century. We present new records of SST and sea surface salinity (SSS) spanning 1959-2010 based on paired measurements of Sr/Ca and ?18O in a massive Porites coral from Butaritari atoll in the Gilbert Islands, Republic of Kiribati, in the central western equatorial Pacific. The records show 2-7 year variability correlated with the El Niño-Southern Oscillation (ENSO) and corresponding shifts in the extent of the Indo-Pacific Warm Pool, and decadal-scale signals related to the Pacific Decadal Oscillation and the Pacific Warm Pool Index. In addition, the Butaritari coral records reveal a small but significant increase in SST (0.39°C) from 1959 to 2010 with no accompanying change in SSS, a trend that persists even when ENSO variability is removed. In contrast, larger increases in SST and SSS are evident in coral records from the equatorial Pacific Line Islands, located east of Butaritari. Taken together, the equatorial Pacific coral records suggest an overall reduction in the east-west SST and SSS gradient over the last several decades, and a recent weakening of the Walker Circulation.

Carilli, Jessica E.; McGregor, Helen V.; Gaudry, Jessica J.; Donner, Simon D.; Gagan, Michael K.; Stevenson, Samantha; Wong, Henri; Fink, David

2014-11-01

224

Rashba-induced chirality switching of domain walls and suppression of the Walker breakdown  

NASA Astrophysics Data System (ADS)

We investigate the current-induced motion of ferromagnetic domain walls in the presence of a Rashba spin-orbit interaction of the itinerant electrons. We show how a Rashba interaction can stabilize the domain wall motion, such that the Walker breakdown is shifted to larger current densities. The Rashba spin-orbit interaction creates a fieldlike contribution to the spin torque, which breaks the symmetry of the system and modifies the internal structure of the domain wall. Moreover, it can induce an additional switching of the chirality of the domain wall for sufficiently strong Rashba interactions. This allows one to choose the desired chirality by choosing the direction of the applied spin-polarized current. Both the suppression of the Walker breakdown and the chirality switching affect the domain wall velocity significantly. This is even more pronounced for short current pulses, where an additional domain wall drift in either positive or negative direction appears after the pulse ends. By this, we can steer the final position of the domain wall. This mechanism may help to overcome the current limitations of the domain wall motion due to the Walker breakdown which occurs for rather low current densities in systems without a Rashba spin-orbit interaction.

Stier, Martin; Creutzburg, Marcus; Thorwart, Michael

2014-07-01

225

Compaction properties of crystalline pharmaceutical ingredients according to the Walker model and nanomechanical attributes.  

PubMed

This study investigates the extent to which single-crystal mechanical properties of selected active ingredients (famotidine, nifedipine, olanzapine, piroxicam) influence their bulk compressibility and compactibility. Nanomechanical attributes of oriented single crystals were determined with instrumented nanoindentation, and bulk deformational properties were assessed with the Walker and Heckel models as well as the elastic relaxation index. Good correlations were established between bulk and single-crystal plasticity parameters: the Walker coefficient and indentation hardness. The Walker model showed more practical value for evaluating bulk deformational properties of the APIs investigated because their properties differed more distinctly compared to the Heckel model. In addition, it was possible to predict the elastic properties of the materials investigated at the bulk level because a correlation between the elastic relaxation index and compliance was established. The value of using indentation hardness for crystalline APIs was also confirmed because their compactibility at the bulk level was able to be predicted. Mechanically interlocked structures were characteristic of most polymorphic forms investigated, resulting in single crystals having isotropic mechanical properties. It was revealed that in such cases good correlations between single and bulk mechanical properties can be expected. The results imply that innate crystal deformational properties define their compressibility and compactibility properties to a great extent. PMID:24979532

Egart, M; Ili?, I; Jankovi?, B; Lah, N; Sr?i?, S

2014-09-10

226

Upper-Ocean Heat Balance Processes and the Walker Circulation in CMIP5 Model Projections  

NASA Technical Reports Server (NTRS)

Considerable uncertainty remains as to the importance of mechanisms governing decadal and longer variability of the Walker Circulation, its connection to the tropical climate system, and prospects for tropical climate change in the face of anthropogenic forcing. Most contemporary climate models suggest that in response to elevated CO2 and a warmer but more stratified atmosphere, the required upward mass flux in tropical convection will diminish along with the Walker component of the tropical mean circulation as well. Alternatively, there is also evidence to suggest that the shoaling and increased vertical stratification of the thermocline in the eastern Pacific will enable a muted SST increase there-- preserving or even enhancing some of the dynamical forcing for the Walker cell flow. Over the past decade there have been observational indications of an acceleration in near-surface easterlies, a strengthened Pacific zonal SST gradient, and globally-teleconnected dislocations in precipitation. But is this evidence in support of an ocean dynamical thermostat process posited to accompany anthropogenic forcing, or just residual decadal fluctuations associated with variations in warm and cold ENSO events and other stochastic forcing? From a modeling perspective we try to make headway on this question by examining zonal variations in surface energy fluxes and dynamics governing tropical upper ocean heat content evolution in the WCRP CMIP5 model projections. There is some diversity among model simulations; for example, the CCSM4 indicates net ocean warming over the IndoPacific region while the CSIRO model concentrates separate warming responses over the central Pacific and Indian Ocean regions. The models, as with observations, demonstrate strong local coupling between variations in column water vapor, downward surface longwave radiation and SST; but the spatial patterns of changes in the sign of this relationship differ among models and, for models as a whole, with observations. Our analysis focuses initially on probing the inter-model differences in energy fluxes / transports and Walker Circulation response to forcing. We then attempt to identify statistically the El Nino- / La Nina-related ocean heat content variability unique to each model and regress out the associated energy flux, ocean heat transport and Walker response on these shorter time scales for comparison to that of the anthropogenic signals.

Robertson, F. R.; Roberts, J. B.; Funk, C.; Lyon, B.; Ricciardulli, L.

2012-01-01

227

Limitations of child injury data from the CPSC's National Electronic Injury Surveillance System: the case of baby walker related data.  

PubMed Central

OBJECTIVES: The US Consumer Product Safety Commission's National Electronic Injury Surveillance System (NEISS) is a primary source for children's consumer product injury surveillance data in the US. Differing interpretations of the emergency department based NEISS baby walker data by various parties prompted this detailed examination, reclassification, and analysis of the NEISS data to explain these discrepancies. METHODS: Case selection was performed by searching the NEISS 1982-91 database for the baby walker product code and various text strings for children less than 24 months old. False negative and false positive cases were identified and reclassified. Adjusted population rates were computed and the types and locations of hospitals contributing to the sample were examined. RESULTS: One per cent false positive and 4% false negative misclassification rates were observed. In 1991, two children's hospitals reported 14% of the baby walker related injuries, though these hospitals made up just 2% of the sample frame. Through random allocation, one state currently contains four acute care hospitals and the only two children's hospitals reporting to the NEISS system. These six hospitals contributed 18% of the walker cases whereas the state represents only 3% of the US infant population. CONCLUSIONS: Misclassification in NEISS baby walker reports is minimal, with false negatives outweighing false positives. For trend analysis of product related injuries at the frequency of occurrence observed for baby walkers, NEISS suffers from low sensitivity due to sampling error. For children's injuries, NEISS' estimates have been affected by children's hospitals coming in and out of the sample and currently reflects a random geographic imbalance because one state contributes both of the reporting children's hospitals. To overcome these problems improved multiple product coding, a unique baby walker code, and stratification of children's hospitals in an enlarged NEISS sample is recommended. PMID:9346058

Weiss, H. B.

1996-01-01

228

Siting of Large Volcanic Centers at Releasing Fault Stepovers, Walker Lane Rift  

NASA Astrophysics Data System (ADS)

The transtensional eastern boundary of the Sierran microplate (Walker Lane rift) represents the northernmost extension of the Gulf of California rift, and it forms an onland analog in several ways. It formed at the same time (about 12 Ma), by a similar mechanism: transtension within the thermally- and structurally-weakened axis of a subduction-related arc. The two segments show similar structural trends: NE oblique slip normal faults (Walker Lane) or seafloor spreading centers (Gulf of California), connected by long NNW strike slip faults. However, the process of continental rupture has not yet been completed in the Walker Lane, so the structural controls on transtensional rift volcanism can be directly observed on land. The Walker Lane segment also differs from the Gulf of California segment by showing a northward time-transgressive transition from arc rift magmatism to continental rift magmatism, following the northward migration of the Mendocino triple junction (MTJ). The effect of MTJ migration has been previously recognized in arc to rift geochemical transitions, but not in the timing of development of large arc volcanic fields. For the past ~11-12 Ma, the biggest arc rift and continental rift volcanic centers or fields have been sited on major releasing fault stepovers on the trailing edge of the Sierran microplate. Additionally, major transtensional arc rift centers or fields appear to have progressively migrated northward with time, in advance of the TMJ, although gaps exist in detailed map and age data. These large transtensional arc volcanic fields/centers are, from south to north (oldest to youngest): (1) A ~11 - 9 Ma arc volcanic field that lies along the Sierran crest and rangefront in the Sonora Pass - Bridgeport area of the central Sierra Nevada. Its transtensional structural setting and its size (~ 50 X 50 km) had not been appreciated prior to my field efforts with students, although a modest-sized caldera in this volcanic field had long been recognized ("Little Walker caldera" of Priest, 1979). At this center, "flood andesites" were erupted from 6-8 km long fault-controlled fissures and ponded in grabens, to thicknesses of 400 m, with single flows up to 25 km3 in volume. Total volume is difficult to estimate due to Pleistocene glacial erosion, but it is >200 km3. (2) The Ebbetts Pass center, which formed at ~5-4 Ma (dating in progress with Paul Renne, BGC). This large center had not been recognized prior to our mapping; it appears to be a complex central volcano with a large footprint (>16 km diameter, glacially eroded). Its original volume may be better estimated after its collapse deposits are mapped and dated, because it appears to have repeatedly collapsed into range-front half grabens. (3) The active Lassen arc volcanic center, which formed at <3.5 Ma in a transtensional environment "favorable to the development of major volcanic centers" (Muffler et al., 2008, EOS 8-53). The active Long Valley rift volcanic field south of the MTJ also formed in a releasing bend in the Walker Lane transtensional rift (since ~4.5 Ma); the structure of this field (Jayko and Bursik, in press) is remarkably similar to that of the ~11-9 Ma arc rift volcanic field at Sonora Pass (Busby, in press; both in Tectonics of Sedimentary Basins, Wiley Blackwell, 2012).

Busby, C.

2011-12-01

229

An appraisal of the water resources of the Walker River Indian Reservation, Nevada  

USGS Publications Warehouse

Increasing interest in expanding the livestock and agricultural operations on the Walker River Indian Reservation, Nev., has prompted the Walker River Paiute Tribe to have the present and available water resources of the reservation appraised and proposed sites for new wells evaluated. Flow of the Walker River into the reservation averages about 113,000 acre-feet a year. Of this amount, about 42,000 acre-feet is used on the reservation, recharging the gound-water system and supplying irrigation water for alfalfa and pasture crops. The water quality of the river water is well suited for these purposes, and the possibility of expanding surface-water use exists. A mathematical model of the ground-water system was constructed to test various assumptions about recharge and discharge rates. The model generated water-level contours that agreed reasonably well with measured water levels, median deviation was 12 feet. With additional data , the model could be used in the future to test the feasibility of evapotranspiration salvage at the seven proposed sites for new stock and irrigation wells. The primary users of ground water on the reservation are phreatophytes and playa surfaces. They allow ground water to be lost to evaporation. About 19,000 acre-feet per year is lost through this mechanism. Domestic and livestock uses account for only about 250 acre-feet per year. Total recharge to the ground-water system amounts to about 30 ,000 acre-feet per year, and the possibility of more extensive use of ground water on the reservation exists. Quality of the ground water in most areas is suitable for all intended purposes. (USGS)

Schaefer, Donald H.

1980-01-01

230

Central Diabetes Insipidus, Central Hypothyroidism, Renal Tubular Acidosis and Dandy-Walker Syndrome: New Associations  

PubMed Central

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.

Alafif, MM; Aljaid, SS; Al-Agha, AE

2015-01-01

231

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

NASA Astrophysics Data System (ADS)

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.

Huguet, E.; Renaud, J.

2013-02-01

232

Dandy-Walker syndrome and corpus callosum agenesis in 5p deletion.  

PubMed

5p deletion syndrome commonly known as cri du chat is well described in affected neonates with catlike cry and hypotonia. Karyotyping will usually show a deletion of the short arm of one chromosome 5 with variable breakpoints. Only a few cases have been reported prenatally, and the fetal form of the syndrome has not been clearly individualised. We report a new case of 5p deletion syndrome diagnosed prenatally in association with Dandy-Walker syndrome and agenesis of the corpus callosum. Other brain anomalies have been reported previously, but this unusual association suggests the use of a specific probe in the investigation of these malformations. PMID:15849798

Vialard, F; Robyr, R; Hillion, Y; Molina Gomes, D; Selva, J; Ville, Y

2005-04-01

233

The field descriptions for thermal-equilibrium Friedmann-Robertson-Walker universe  

NASA Astrophysics Data System (ADS)

In this paper, we show the simple expression for the energy density of the thermal-equilibrium Friedmann-Robertson-Walker (TEFRW) universe and study the problem how to describe it by using some field models. We analyze the properties of the quintessence field in the quintessence model, calculate the tachyon potential in the tachyon model and point out that the latter model cannot give the whole description for the TEFRW universe. It is found that the two-field model can be responsible for describing the whole evolution process of the TEFRW universe.

Lan, Tianbao; Wei, Yihuan; Fu, Yanyan; Zhang, Yuezhu

2014-06-01

234

A hydrochemical reconnaissance study of the Walker River basin, California and Nevada  

USGS Publications Warehouse

During 1975 and 1976, a large number of water and sediment samples were collected from the Walker River Basin. Additional surface water samples were collected during 1980 and 1981. Data are given herein for chemical analyses of snowmelt, tributary, river, spring, well, lake, reservoir, lake sediment pore fluid, tufa, lake and river sediment samples. These data provide the basis for consideration of processes which govern the chemical evolution of large closed basin hydrologic systems in the Basin and Range Province of the Southwestern United States.

Benson, L.V.; Spencer, R.J.

1983-01-01

235

Changes in lipid metabolism during Walker 256 tumor growth and the therapeutic effect of hyperthermia.  

PubMed

The dynamics of lipoprotein content during Walker 256 tumor growth in rats was studied. Moderate changes in HDL and LDL were paralleled by significant changes in VLDL level. A 2-fold increase of VLDL in comparison with the intact control was recorded on day 10 of tumor growth. Exposure to total hyperthermia additionally stimulated VLDL synthesis and this parameter increased by 4 times and more in rats with tumors in comparison with controls. This effect of hyperthermia correlated with significant subsequent decrease of rat mortality caused by the lethal effect of the tumor. PMID:24824711

Efremov, A V; Khegai, I I; Molokov, K V; Pakhomova, Yu V

2014-04-01

236

Changes in Central Walker Lane Strain Accommodation near Bridgeport, California; as told by the Stanislaus Group  

NASA Astrophysics Data System (ADS)

Accommodating ~20-25% of the dextral-motion between the Pacific and North American plates the Walker Lane is represented as an elongate, NW oriented, region of active tectonics positioned between the northwesterly-translating Sierra Nevada microplate and the east-west extension of the Basin and Range. This region of transtension is being variably accommodated on regional-scale systems of predominantly strike-slip faulting. At the western edge of the central Walker Lane (ca. 38°-39°N latitude) is a region of crustal-scale blocks bounded by wedge-shaped depositional-basins and normal-fault systems, here defined as the west-central Walker Lane (WCWL). Devoid of obvious strike-slip faulting, the presence of tectonic-block vertical-axis rotations in the WCWL represents unrecognized components of dextral-shearing and/or changes of strain-accommodation over time. We use paleomagnetic reference directions for Eureka Valley Tuff (EVT) members of the late Miocene Stanislaus Group as spatial and temporal markers for documentation of tectonic-block vertical-axis rotations near Bridgeport, CA. Study-site rotations revealed discrete rotational domains of mean vertical-axis rotation ranging from ~10°-30° with heterogeneous regional distribution. Additionally, the highest measured magnitudes of vertical-axis rotation (~50°-60° CW) define a 'Region of High Strain' that includes the wedge-shaped Bridgeport Valley (Basin). This study revealed previously-unrecognized tectonic rotation of reference direction sites from prior studies for two (By-Day and Upper) of the three members of the EVT, resulting in under-estimates of regional strain accommodation by these studies. Mean remanent directions and virtual geomagnetic poles utilized in our study yielded a recalculated reference direction for the By-Day member of: Dec.=353.2°; Inc.= 43.7°; ?95=10.1, in agreement with new measurements in the stable Sierra Nevada. This recalculated direction confirmed the presence of previously unrecognized reference site rotations, and provided an additional reference direction for determining vertical-axis rotation magnitudes. We present a kinematic model based on mean rotation magnitudes of ~30° CW for the Sweetwater Mountains and Bodie Hills that accounts for rotational-strain accommodation of dextral shear in the WCWL since the late Miocene. This model considers rotational magnitudes, paleostrain indicators, edge-effects, and strain-accommodating structures of rotating crustal blocks to represent changes in regional strain accommodation over time. The results and models presented here elucidate the complicated and evolving nature of the WCWL, and further understanding of variations in strain accommodation for the Walker Lane.

Carlson, C. W.; Pluhar, C. J.; Glen, J. M.; Farner, M. J.

2012-12-01

237

Insight into reduction of obacunone, and their ester derivatives as insecticidal agents against Mythimna separata Walker.  

PubMed

Here we have prepared a series of ester compounds of obacunone, a naturally occurring limonoid, isolated from plants such as Citrus and Dictamnus angustifolius. Their insecticidal activity was evaluated at 1 mg/mL against the pre-third-instar larvae of oriental armyworm (Mythimna separata Walker), a typical lepidopteran pest. When obacunone reacted with NaBH?, the ratio of two reduction products, C7?-hydroxyobacunone (2) and C7?-hydroxyobacunone (3), was related to the reaction mixing solvents. C7?-Propionyloxybacunone (4b) and C7?-(n)heptanoyloxybacunone (5g) exhibited the more promising insecticidal activity than their precursor obacunone and toosendanin. PMID:25465171

Yu, Xiang; Ding, Guodong; Zhi, Xiaoyan; Xu, Hui

2015-01-01

238

On the Creation of Scalar Particles in a Flat Robertson-Walker Spacetime  

NASA Astrophysics Data System (ADS)

The problem of particle creation from vacuum in a flat Robertson-Walker spacetime is studied. Two sets of exact solutions for the Klein-Gordon equation are given when the scale factor is a2(?) = a+b tanh(??)+c tanh2 (??). Then the canonical method based on Bogoliubov transformation is applied to calculate the pair creation probability and the density number of created particles. Some particular cosmological models such as radiation dominated universe and Milne universe are discussed. For both cases the vacuum to vacuum transition probability is calculated and the imaginary part of the effective action is extracted.

Haouat, S.; Chekireb, R.

239

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

PubMed

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

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

2015-01-01

240

Effect of flavonoids on feeding preference and development of the crucifer pest Mamestra configurata Walker.  

PubMed

Thirty-seven flavonoid compounds (9 flavones, 18 flavonols, 8 flavanones, and 2 flavanonols) were investigated for their effect on feeding choice with bertha armyworm (Mamestra configurata Walker; BAW). Feeding choice was dependent upon subtle differences in biochemical structure. Unsubstituted flavone and flavanone were the strongest feeding deterrents in the choice bioassay, while 7.4'-dihydroxyflavone and dihydroquercetin stimulated BAW to feed. The constitutive flavonoids of Brassica napus, isorhamnetin-3-sophoroside-7-glucoside and kaempferol-3,7-diglucoside, were effective deterrents when supplemented at concentrations higher than endogenous levels. In a no-choice bioassay, flavone reduced both larval weight as well as larval and pupal development time. PMID:15074660

Onyilagha, Joseph C; Lazorko, Jennifer; Gruber, Margaret Y; Soroka, Juliana J; Erlandson, Martin A

2004-01-01

241

The influence of ocean surface temperature gradient and continentality on the Walker circulation. I - Prescribed tropical changes  

NASA Technical Reports Server (NTRS)

A coarse mesh global climate model has been developed to assess ocean surface temperature (OST) gradient and continentality influences on the Walker circulation, which is characterized in the zonal plane by three pairs of clockwise and counterclockwise cells in the troposphere. The model response exhibits statistically significant changes in the intensity of the various cells and branches with small shifts in the east-west extent. The overall structure in the zonal plane for experiments with the coldest and with mean temperatures, however, remained unchanged. In an experiment involving the replacement of the South American continent by an ocean with OSTs linearly interpolated from the eastern Pacific to the western Atlantic, a dramatic change took place in the structure of the Walker circulation. It is concluded that both continentality and OST gradient are important Walker circulation forcing mechanisms.

Chervin, R. M.; Druyan, L. M.

1984-01-01

242

On a Bipolar Model of Hyperbolic Geometry and its Relation to Hyperbolic Robertson-Walker Space  

E-print Network

Negatively curved, or hyperbolic, regions of space in an FRW universe are a realistic possibility. These regions might occur in voids where there is no dark matter with only dark energy present. Hyperbolic space is strange and various "models" of hyperbolic space have been introduced, each offering some enlightened view. In the present work we develop a new bipolar model of hyperbolic geometry, closely related to an existing model - the band model - and show that it provides new insights toward an understanding of hyperbolic as well as elliptic Robertson-Walker space and the meaning of its isometries. In particular, we show that the circular geodesics of a hyperbolic Robertson-Walker space can be referenced to two real centers - a Euclidean center and an offset hyperbolic center. These are not the Euclidean center or poles of the bipolar coordinate system but rather refer to two distinct centers for circular orbits of particles in such systems. Considering the physics of elliptic RW space is so well confirmed in the Lambda-CDM model with respect to Euclidean coordinates from a Euclidean center, it is likely that the hyperbolic center plays a physical role in regions of hyperbolic space.

Harry I. Ringermacher; Lawrence R. Mead

2012-01-25

243

Distribution of the time at which N vicious walkers reach their maximal height.  

PubMed

We study the extreme statistics of N nonintersecting Brownian motions (vicious walkers) over a unit time interval in one dimension. Using path-integral techniques we compute exactly the joint distribution of the maximum M and of the time ?(M) at which this maximum is reached. We focus in particular on nonintersecting Brownian bridges ("watermelons without wall") and nonintersecting Brownian excursions ("watermelons with a wall"). We discuss in detail the relationships between such vicious walkers models in watermelon configurations and stochastic growth models in curved geometry on the one hand and the directed polymer in a disordered medium (DPRM) with one free end point on the other hand. We also check our results using numerical simulations of Dyson's Brownian motion and confront them with numerical simulations of the polynuclear growth model (PNG) and of a model of DPRM on a discrete lattice. Some of the results presented here were announced in a recent letter [J. Rambeau and G. Schehr, Europhys. Lett. 91, 60006 (2010)]. PMID:21797341

Rambeau, Joachim; Schehr, Grégory

2011-06-01

244

Changes in liver gluconeogenesis during the development of Walker-256 tumour in rats  

PubMed Central

Few studies have investigated liver gluconeogenesis in cancer and there is no agreement as to whether the activity of this pathway is increased or decreased in this disease. The aim of this study was to evaluate gluconeogenesis from alanine, pyruvate and glycerol, and related metabolic parameters in perfused liver from Walker-256 tumour-bearing rats on days 5 (WK5 group), 8 (WK8 group) and 12 (WK12 group) of tumour development. There was reduction (P < 0.05) of liver glucose production from alanine and pyruvate in WK5, WK8 and WK12 groups, which was accompanied by a decrease (P < 0.05) in oxygen consumption. Moreover, there was higher (P < 0.05) pyruvate and lactate production from alanine in the WK5 group and a marked reduction (P < 0.05) of pyruvate and urea production from alanine in the WK12 group. In addition, liver glucose production and oxygen consumption from glycerol were not reduced in WK5, WK8 and WK12 groups. Thus the, the results show inhibition of hepatic gluconeogenesis from alanine and pyruvate, but not from glycerol, on days 5, 8 and 12 of Walker-256 tumour development, which can be attributed to the metabolic step in which the substrate enters the gluconeogenic pathway. PMID:23317353

Moreira, Carolina Campos Lima; Cassolla, Priscila; Dornellas, Ana Paula Segantini; Morais, Hely; Souza, Camila Oliveira; Borba-Murad, Glaucia Regina; Bazotte, Roberto Barbosa; Souza, Helenir Medri

2013-01-01

245

Optimal covariant fitting to a Robertson-Walker metric and smallness of backreaction  

E-print Network

We define a class of "optimal" coordinate systems by requiring that the deviation from an exact Robertson-Walker metric is "as small as possible" within a given four dimensional volume. The optimization is performed by minimizing several volume integrals which would vanish for an exact Robertson-Walker metric. Covariance is automatic. Foliation of space-time is part of the optimization procedure. Only the metric is involved in the procedure, no assumptions about the origin of the energy-momentum tensor are needed. A scale factor does not show up during the optimization process, the optimal scale factor is determined at the end. The general formulation is non perturbative. An explicit perturbative treatment is possible. The shifts which lead to the optimal coordinates obey Euler-Lagrange equations which are formulated and solved in first order of the perturbation. The extension to second order is sketched, but turns out to be unnecessary. The only freedom in the choice of coordinates which finally remains are ...

Gromes, Dieter

2011-01-01

246

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

SciTech Connect

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.

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

1987-12-31

247

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

PubMed Central

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

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

248

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

PubMed

We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation and occipital cephaloceles and detected a mutation in the extracellular matrix (ECM) 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 of the NID1-LAMC1 complex demonstrated that each mutation disrupts the interaction. These findings implicate the ECM in the pathogenesis of Dandy-Walker spectrum disorders. PMID:23674478

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

2013-08-01

249

Random Discrete Structures, ed. D. Aldous and R. Pemantle, Springer, New York, 1996, pp. 185--198. How Fast and Where Does a Random Walker  

E-print Network

a long time, about how far is the walker from the root? 1991 Mathematics Subject Classification. Primary that an equivalent assertion comes from electrical networks: Assume that each edge of the tree is a unit conductor--198. How Fast and Where Does a Random Walker Move on a Random Tree? By Russell Lyons Abstract. The oldest

Lyons, Russell

250

Living with Kin in Lowland Horticultural Societies Author(s): Robert S. Walker, Stephen Beckerman, Mark V. Flinn, Michael Gurven, Chris R.  

E-print Network

Living with Kin in Lowland Horticultural Societies Author(s): Robert S. Walker, Stephen Beckerman with Kin in Lowland Horticultural Societies Robert S. Walker, Stephen Beckerman, Mark V. Flinn, Michael-gatherer cultures has led to their characterization as primarily multilocal. Horticulturalists are associated

Gurven, Michael

251

Breast Cancer Mortality vs. Exercise and Breast Size in Runners and Walkers  

PubMed Central

Purpose Identify predictors of breast cancer mortality in women who exercised below (<7.5 metabolic equivalent hours/week, MET-hours/wk), at (7.5 to 12.5 MET-hours/wk), or above (?12.5 MET-hours/wk) recommended levels. Methods Cox proportional hazard analyses of baseline pre-diagnosis MET-hours/wk vs. breast cancer mortality adjusted for follow-up age, race, baseline menopause, and estrogen and oral contraceptive use in 79,124 women (32,872 walkers, 46,252 runners) from the National Walkers' and Runners' Health Studies. Results One-hundred eleven women (57 walkers, 54 runners) died from breast cancer during the 11-year follow-up. The decline in mortality in women who exercised ?7.5 MET-hours/wk was not different for walking and running (P?=?0.34), so running and walking energy expenditures were combined. The risk for breast cancer mortality was 41.5% lower for ?7.5 vs. <7.5 MET-hours/wk (HR: 0.585, 95%CI: 0.382 to 0.924, P?=?0.02), which persisted when adjusted for BMI (HR: 0.584, 95%CI: 0.368 to 0.956, P?=?0.03). Other than age and menopause, baseline bra cup size was the strongest predictor of breast cancer mortality, i.e., 57.9% risk increase per cup size when adjusted for MET-hours/wk and the other covariates (HR: 1.579, 95%CI: 1.268 to 1.966, P<0.0001), and 70.4% greater when further adjusted for BMI (HR: 1.704, 95%CI: 1.344 to 2.156, P?=?10?5). Breast cancer mortality was 4.0-fold greater (HR: 3.980, 95%CI: 1.894 to 9.412, P?=?0.0001) for C-cup, and 4.7-fold greater (HR: 4.668, 95%CI: 1.963 to 11.980, P?=?0.0004) for ?D-cup vs. A-cup when adjusted for BMI and other covariates. Adjustment for cup size and BMI did not eliminate the association between breast cancer mortality and ?7.5 MET-hour/wk walked or run (HR: 0.615, 95%CI: 0.389 to 1.004, P?=?0.05). Conclusion Breast cancer mortality decreased in association with both meeting the exercise recommendations and smaller breast volume. PMID:24349006

Williams, Paul T.

2013-01-01

252

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

E-print Network

is considered a harmful algal bloom species due to the significant indirect effects it has on local systems viaGiantism and its role in the harmful algal bloom species Phaeocystis globosa Walker O. Smith Jr Institute of Oceanography, Vietnam Academy of Science & Technology, 01 Cau Da, Nha Trang, Viet Nam c

Newman, Michael C.

253

Design and Construction of a Simple 3D Straight-Legged Passive Walker with Flat Feet and Ankle Springs  

NASA Astrophysics Data System (ADS)

To date, most passive walkers have been designed with arc-shaped feet rigidly attached to the legs. However, the friction torque against yaw is often insufficient because of their contact conditions with the ground. We developed a simple 3D straight-legged passive walker with flat feet and ankle springs. Flat feet were used to gain enough scrubbing friction to oppose unstable yaw motion. Springs were attached to the ankle to produce torque resulting in roll and pitch motions that mimic those of 3D passive walkers with arc-shaped feet, while the friction torque against yaw should be sufficient. The spring constant for the roll motion at the stance ankle is obviously an important factor in enabling the straight-legged robot to rock adequately from side to side to avoid problematic scuffing of the swing leg so it can swing forward. We used numerical simulations to determine the value of the spring constant. Experimental results indicated that our 3D straight-legged passive walker with a 0.77-m leg can walk more than 2 m at about 0.46 m/s.

Narukawa, Terumasa; Yokoyama, Kazuto; Takahashi, Masaki; Yoshida, Kazuo

254

Design and Control of a Clutch for a Minimally-Actuated Biped Based on the Passive-Dynamic Simple Walker  

E-print Network

at the Massachusetts Institute of Technology. Abstract Passive-dynamic walking robots are remarkable mechanical devicesDesign and Control of a Clutch for a Minimally-Actuated Biped Based on the Passive-Dynamic Simple Based on the Passive-Dynamic Simple Walker by Arlis Reynolds Submitted to the Department of Mechanical

Tedrake, Russ

255

donald a. WalkEr, Martha k. raynolds, MarcEl buchhorn and Jana l. PEircE  

E-print Network

alaska's north slope oilfields are the most exten- sive and one of the oldest industrial complexes 3 supplementary information regarding calculation of impacts of oilfield development, north slope and permafrost changes in the prudhoe Bay oiLfieLd, aLaska DonalD a. Walker, Martha k. raynolDs, yuri l. shur

Hartman, Chris

256

Simulation of the Lower Walker River Basin hydrologic system, west-central Nevada, using PRMS and MODFLOW models  

USGS Publications Warehouse

For the baseline scenario, it was assumed that streamflow conditions from 1981 to 2010 will be repeated in the future. Results indicate that Walker Lake level and volume continue to decline but at a slower rate as the surface area of th

Allander, Kip K.; Niswonger, Richard G.; Jeton, Anne E.

2014-01-01

257

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

ERIC Educational Resources Information Center

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…

O'Brien, John

2013-01-01

258

A Robertson-Walker Universe in the post-Einstein theory of gravitation and within a series of other theories  

NASA Astrophysics Data System (ADS)

Post-Einstein theory of gravitation (PETG) is suggested. The PETG equations for a Robertson-Walker cosmological model are obtained. It is shown that in PETG and in some other theories a ‘dynamical’ Universe cannot be realized as the configuration of a ‘common’ matter.

Karbanovski, V. V.; Beloushko, K. E.; Tarasova, A. S.; Makurin, A. B.; Mironova, M. V.

2012-03-01

259

Limitations of child injury data from the CPSC's National Electronic Injury Surveillance System: the case of baby walker related data  

Microsoft Academic Search

OBJECTIVES: The US Consumer Product Safety Commission's National Electronic Injury Surveillance System (NEISS) is a primary source for children's consumer product injury surveillance data in the US. Differing interpretations of the emergency department based NEISS baby walker data by various parties prompted this detailed examination, reclassification, and analysis of the NEISS data to explain these discrepancies. METHODS: Case selection was

H. B. Weiss

1996-01-01

260

Changes in nutrient distribution in forests and soils of Walker Branch watershed, Tennessee, over an eleven-year period  

Microsoft Academic Search

Changes in vegetation, litter, and soil nutrient content were measured in selected plots on Walker Branch watershed, Tennessee, from 1972–73 to 1982. The watershed has been allowed to revert to forest since 1942, before which it consisted of small subsistence farms and woodland pastures. Changes in Ca status were of particular interest because initial nutrient cycling characterizations indicated that net

Dale W. Johnson; Gray S. Henderson; Donald E. Todd

1988-01-01

261

Nonlinear static decoupling of six-dimension force sensor for walker dynamometer system based on artificial neural network  

Microsoft Academic Search

The static coupling of six-dimension force sensor for walker dynamometer system is a key factor to limit its measuring precision. A new decoupling method based on artificial neural network is proposed in this paper. Relevant error check results shows that, after the calibration by using the back propagation neural network and radial basis function neural networks, the maximal system precision

Dong Ming; Xi Zhang; Xiuyun Liu; Baikun Wan; Yong Hu; K. D. K. Luk

2009-01-01

262

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...

263

Description of a new species and subspecies of Idalus Walker from Costa Rica, Honduras and Guatemala (Lepidoptera, Erebidae, Arctiinae, Arctiini)  

PubMed Central

Abstract A new species and subspecies of Idalus Walker are described from Costa Rica, Honduras and Guatemala. Images of males and females and their genitalia are provided. Locality information and distribution maps for Costa Rica and for Guatemala are included. The biology and phylogeny of Idalus are discussed. PMID:23730178

Espinoza, Bernardo A.; Janzen, Daniel H.; Winnie Hallwachs;  J. Bolling Sullivan

2013-01-01

264

FISCAL FORESIGHT: ANALYTICS AND ECONOMETRICS ERIC M. LEEPER, TODD B. WALKER, AND SHU-CHUN SUSAN YANG  

E-print Network

FISCAL FORESIGHT: ANALYTICS AND ECONOMETRICS ERIC M. LEEPER, TODD B. WALKER, AND SHU-CHUN SUSAN policy process. This paper develops an analytical framework to study the econometric implications from statistical innovations in conventional ways. Econometric analyses that fail to align agents

Hickman, Mark

265

Barry Jacobs, Jetse Kalma, Greg Hancock, Manju Hemakumara, Jeffrey Walker, and Garry Willgoose (2004), Towards understanding the spa-  

E-print Network

Barry Jacobs, Jetse Kalma, Greg Hancock, Manju Hemakumara, Jeffrey Walker, and Garry Willgoose distribution and dynamics of soil organic carbon within a large temperate agricultural catchment Barry Jacobs1 25­27 #12;Jacobs Session 3 CAHMDA-II workshop Towards understanding the spatial and temporal

Walker, Jeff

266

A path following feedback control law for a new type of undulatory locomotor: A trident steering walker  

Microsoft Academic Search

This paper presents a path following feedback control law for an undulatory wheeled locomotor referred to as a ldquotrident steering walker.rdquo This undulatory wheeled locomotor makes undulatory locomotion in which it transforms the rotations of its three joints into its movement by using four steering mechanisms. In this feedback control law, we especially replace some mechanical elements of the trident

Hiroaki Yamaguchi

2009-01-01

267

Evaluation of the OhmMapper Instrument for Soil Moisture Measurement Jeffrey P. Walker* and Paul R. Houser  

E-print Network

is the could be used to infer soil moisture content with a coefficient of OhmMapper by Geometrics Inc. (San the OhmMapper's potential to mapwas used. A more sophisticated analysis of the resistivity measure- rootEvaluation of the OhmMapper Instrument for Soil Moisture Measurement Jeffrey P. Walker* and Paul R

Walker, Jeff

268

Character, community, and the form of ethics in four American regionalists: Alice Cary, Kate Chopin, Walker Percy, Larry Brown  

Microsoft Academic Search

The aim of “Character, Community, and the Form of Ethics in Four American Regionalists” is to recognize and establish the interconnection of literary form and ethical content as a distinctive feature of American regionalist fiction, in general, and in the work of Alice Cary, Kate Chopin, Walker Percy, and Larry Brown, in particular. The study adopts a hermeneutical method drawn

John Anthony Staunton

1999-01-01

269

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

E-print Network

/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

Busby, Cathy

270

Parallel FaultTolerant Robot Control D.L. Hamilton, J.K. Bennett, and I.D. Walker  

E-print Network

problem. Advances in robot control theory have produced algorithms that are difficult to implementParallel Fault­Tolerant Robot Control D.L. Hamilton, J.K. Bennett, and I.D. Walker Dept. of Electrical and Computer Engineering Rice University, Houston, TX 77251 ABSTRACT Most robot controllers today

Bennett, John K.

271

Neurocutaneous Melanosis in Association with Dandy-Walker Complex with Extensive Intracerebral and Spinal Cord Involvement  

PubMed Central

Neurocutaneous melanosis (NCM) is a rare congenital syndrome consisting of benign or malignant melanotic tumors of the central nervous system with large or numerous cutaneous melanocytic nevi. The Dandy-Walker complex (DWC) is characterized by an enlarged posterior fossa with high insertion of the tentorium, hypoplasia or aplasia of the cerebellar vermis, and cystic dilatation of the fourth ventricle. These each two conditions are rare, but NCM associated with DWC is even more rare. Most patients of NCM with DWC present neurological symptoms early in life such as intracranial hemorrhage, hydrocephalus, and malignant transformation of the melanocytes. We report a 14-year-old male patient who was finally diagnosed as NCM in association with DWC with extensive intracerebral and spinal cord involvement. PMID:25289129

Sung, Kyoung-Su

2014-01-01

272

Large scale dynamics of the Persistent Turning Walker model of fish behavior  

E-print Network

This paper considers a new model of individual displacement, based on fish motion, the so-called Persistent Turning Walker (PTW) model, which involves an Ornstein-Uhlenbeck process on the curvature of the particle trajectory. The goal is to show that its large time and space scale dynamics is of diffusive type, and to provide an analytic expression of the diffusion coefficient. Two methods are investigated. In the first one, we compute the large time asymptotics of the variance of the individual stochastic trajectories. The second method is based on a diffusion approximation of the kinetic formulation of these stochastic trajectories. The kinetic model is a Fokker-Planck type equation posed in an extended phase-space involving the curvature among the kinetic variables. We show that both methods lead to the same value of the diffusion constant. We present some numerical simulations to illustrate the theoretical results.

Pierre Degond; Sébastien Motsch

2007-10-26

273

Feasible domain of Walker's unsteady wall-layer model for the velocity profile in turbulent flows.  

PubMed

The present work studies, in detail, the unsteady wall-layer model of Walker et al. (1989, AIAA J., 27, 140 – 149) for the velocity profile in turbulent flows. Two new terms are included in the transcendental nonlinear system of equations that is used to determine the three main model parameters. The mathematical and physical feasible domains of the model are determined as a function of the non-dimensional pressure gradient parameter (p+). An explicit parameterization is presented for the average period between bursts (T+B), the origin of time (t+0 ) and the integration constant of the time dependent equation (A0) in terms of p+. In the present procedure, all working systems of differential equations are transformed, resulting in a very fast computational procedure that can be used to develop real-time flow simulators. PMID:25590746

Mikhailov, Mikhail D; Freire, Atila P Silva

2014-12-01

274

Autonomous Multistep Organic Synthesis in a Single Isothermal Solution Mediated by a DNA Walker  

PubMed Central

Multistep synthesis in the laboratory typically requires numerous reaction vessels, each containing a different set of reactants. In contrast, cells are capable of performing highly efficient and selective multistep biosynthesis under mild conditions with all reactants simultaneously present in solution. If the latter approach could be applied in the laboratory, it may improve the ease, speed, and efficiency of multistep reaction sequences. Here we show that a DNA mechanical device— a DNA walker moving along a DNA track— can be used to perform a series of amine acylation reactions in a single solution without any external intervention. The multistep products generated by this primitive ribosome mimetic are programmed by the sequence of the DNA track, are unrelated to the structure of DNA, and are formed with speeds and overall yields significantly greater than those previously achieved by multistep DNA-templated small-molecule synthesis. PMID:20935654

He, Yu; Liu, David R.

2010-01-01

275

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

PubMed Central

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

Wu, Chun-Sheng; Solovyev, Alexey V.

2011-01-01

276

Holoprosencephaly with Dandy-Walker cyst. Rare coexistence of two major malformations.  

PubMed

A case of holoprosencephaly associated with Dandy-Walker cyst is reported. The patient was a male baby whose mother had normal serum titers for toxoplasma, syphilis, rubella and hepatitis B. She had no history of diabetes mellitus, administration of drugs or irradiation during the pregnancy. At the 8th month of gestation, fetal hydrocephalus was diagnosed by ultrasonic imaging. He was delivered by caesarean section at 34 weeks and 4 days, weighing 2,644 g. His head circumference was 42 cm; the anterior fontanel was not distended and its tension was normal. The chromosomal karyotype was a normal 46 XY. X-ray CT showed a large dorsal sac cyst in the supratentorial space and a hypoplastic cerebellum with a large cyst in the posterior fossa. He received a cyst-peritoneal shunt 24 days after birth. After this procedure, his head enlargement was arrested. We discuss the etiology of this rare coexistence of two major malformations. PMID:2178775

Kurokawa, Y; Tsuchita, H; Sohma, T; Kitami, K; Takeda, T; Hattori, S

1990-01-01

277

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

E-print Network

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.

Joachim Schroeter

2009-07-03

278

Host-habitat location by the parasitoid, Nasonia vitripennis Walker (Hymenoptera: Pteromalidae).  

PubMed

This study investigated the role of odorant cues used during host-habitat location by the generalist parasitoid, Nasonia vitripennis Walker. Nasonia vitripennis is a common parasitoid of Dipteran pupae found in association with decaying carrion. Behavioral assays were used to investigate the host-habitat searching behavior under different scenarios. First, we demonstrated N. vitripennis to be significantly attracted toward odorant cues associated with decaying meat. The biological activity of nine of the volatile molecules constituting the odor of decaying meat was tested on the searching behavior of parasitoid females through two complementary chemoecological approaches: electroantennography (EAG) and olfactometry bioassays. Butanoic acid and butan-1-ol elicited high olfactory responses, but no attraction was induced by these two chemicals. Behavioral assays showed that, among the VOCs tested, methyldisulfanylmethane (DMDS) was the only volatile chemical to induce attraction in N. vitripennis. PMID:23980702

Frederickx, Christine; Dekeirsschieter, Jessica; Verheggen, Francois J; Haubruge, Eric

2014-01-01

279

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

280

Mutations in ISPD cause Walker-Warburg syndrome and defective glycosylation of ?-dystroglycan  

PubMed Central

Walker-Warburg syndrome (WWS) is an autosomal recessive multisystem disorder characterized by complex eye and brain abnormalities with congenital muscular dystrophy (CMD) and aberrant ?-dystroglycan (?DG) glycosylation. Here, we report mutations in the isoprenoid synthase domain-containing (ISPD) gene as the second most common cause of WWS. Bacterial IspD is a nucleotidyl transferase belonging to a large glycosyltransferase family, but its role in chordates has been obscure to date because this phylum does not have the corresponding non-mevalonate isoprenoid biosynthesis pathway. Knockdown of ispd in zebrafish recapitulates the human WWS phenotype with hydrocephalus, reduced eye size, muscle degeneration and hypoglycosylated ?DG. These results implicate a role for ISPD in ?DG glycosylation to maintain sarcolemma integrity in vertebrates. PMID:22522421

Roscioli, Tony; Kamsteeg, Erik-Jan; Buysse, Karen; Maystadt, Isabelle; van Reeuwijk, Jeroen; van den Elzen, Christa; van Beusekom, Ellen; Riemersma, Moniek; Pfundt, Rolph; Vissers, Lisenka E.L.M.; Schraders, Margit; Altunoglu, Umut; Buckley, Michael F.; Brunner, Han G.; Grisart, Bernard; Zhou, Huiqing; Veltman, Joris A.; Gilissen, Christian; Mancini, Grazia M.S.; Delrée, Paul; Willemsen, Michèl A.; Ramadža, Danijela Petkovi?; Chitayat, David; Bennett, Christopher; Sheridan, Eamonn; Peeters, Els A.J.; Tan-Sindhunata, Gita M.B.; de Die-Smulders, Christine E.; Devriendt, Koenraad; Kayserili, Hülya; El-Hashash, Osama Abd El-Fattah; Stemple, Derek L.; Lefeber, Dirk J.; Lin, Yung-Yao; van Bokhoven, Hans

2012-01-01

281

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

PubMed

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

Liu, Guangfu; Xu, Yipeng; Yu, Xiaoping

2015-03-01

282

Big Bang singularity in the Friedmann-Lemaitre-Robertson-Walker spacetime  

E-print Network

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. These results follow from our research on singular semi-Riemannian geometry and singular General Relativity (arXiv:1105.0201, arXiv:1105.3404, arXiv:1111.0646) (which we applied in previous articles to the black hole singularities: arXiv:1111.4837, arXiv:1111.4332, arXiv:1111.7082, arXiv:1108.5099).

Ovidiu-Cristinel Stoica

2012-03-16

283

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

PubMed

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

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

2013-12-19

284

The eastward shift of the Walker Circulation in response to global warming and its relationship to ENSO variability  

NASA Astrophysics Data System (ADS)

This study investigates the global warming response of the Walker Circulation and the other zonal circulation cells (represented by the zonal stream function), in CMIP3 and CMIP5 climate models. The changes in the mean state are presented as well as the changes in the modes of variability. The mean zonal circulation weakens in the multi model ensembles nearly everywhere along the equator under both the RCP4.5 and SRES A1B scenarios. Over the Pacific the Walker Circulation also shows a significant eastward shift. These changes in the mean circulation are very similar to the leading mode of interannual variability in the tropical zonal circulation cells, which is dominated by El Niño Southern Oscillation variability. During an El Niño event the circulation weakens and the rising branch over the Maritime Continent shifts to the east in comparison to neutral conditions (vice versa for a La Niña event). Two-thirds of the global warming forced trend of the Walker Circulation can be explained by a long-term trend in this interannual variability pattern, i.e. a shift towards more El Niño-like conditions in the multi-model mean under global warming. Further, interannual variability in the zonal circulation exhibits an asymmetry between El Niño and La Niña events. El Niño anomalies are located more to the east compared with La Niña anomalies. Consistent with this asymmetry we find a shift to the east of the dominant mode of variability of zonal stream function under global warming. All these results vary among the individual models, but the multi model ensembles of CMIP3 and CMIP5 show in nearly all aspects very similar results, which underline the robustness of these results. The observed data (ERA Interim reanalysis) from 1979 to 2012 shows a westward shift and strengthening of the Walker Circulation. This is opposite to what the results in the CMIP models reveal. However, 75 % of the trend of the Walker Circulation can again be explained by a shift of the dominant mode of variability, but here towards more La Niña-like conditions. Thus in both climate change projections and observations the long-term trends of the Walker Circulation seem to follow to a large part the pre-existing dominant mode of internal variability.

Bayr, Tobias; Dommenget, Dietmar; Martin, Thomas; Power, Scott B.

2014-11-01

285

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

NASA Astrophysics Data System (ADS)

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.

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

1989-11-01

286

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

NASA Technical Reports Server (NTRS)

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.

1953-01-01

287

TIMING, EXTENT, AND SPATIAL PROGRESSION OF NEOGENE DISPLACEMENT TRANSFER, SOUTHERN WALKER LANE, WESTERN GREAT BASIN  

NASA Astrophysics Data System (ADS)

Displacement transfer through structural stepovers linking misaligned segments of large-magnitude intracontinental transcurrent faults involve components of translational and rotational displacement and strain accommodated by complex three-dimensional arrays of structures. Although vertical-axis rotation of large spatial domains is well documented in many structural stepovers, the degree to which rotation is accommodated by rigid block and/or by distributed strain is not adequately resolved. Similarly, it is seldom established whether or to what degree translational and rotational deformation occur simultaneously over broad regions or if they are parts of a tectonic process involving different components of translational and rotational deformation occurring in spatially and temporally discrete domains. Our current understanding suggests that the displacement transfer system linking faults of the northern Eastern California Shear Zone and central Walker Lane during the mid-Miocene through the mid-Pliocene involves the development of three detachment fault systems underlying a NW-SE trending region stretching from the region east of Death Valley to beyond the northern end of the White Mountains and encompassing southern Walker Lane in Nevada. Integrated geologic mapping, paleomagnetic, thermochronologic ((U-Th)/HE), and structural analysis provides insight into the history and kinematics of transcurrent, high-angle normal faulting and slip on low-angle detachment faults and their relation to differential rotation of upper-plate, and locally lower-plate, rocks. Two extensional systems (Funeral - Bullfrog - Bare Mountain and Silver Peak - Lone Mountain) broadly share an inception age but the age of the third (Gold Mountain) is unknown. The extensional complexes apparently show a progressive decrease in the age at which exhumation ceased from SE to NW, over a duration of about 5 Ma. In contrast, the magnitude of clockwise rotation of upper-plate, and locally of lower-plate, rocks increases from NW to SE from ~20°, ~50, and up to 90°. Our observations improve on our understanding of the spatial and temporal pattern of deformation and supply the constraints to differentiate coeval and serial translational and rotational deformation histories in this nascent plate boundary zone.

Geissman, J. W.; Oldow, J. S.; Stockli, D. F.; Grow, J. S.

2009-12-01

288

Anaerobic exercise reduces tumor growth, cancer cachexia and increases macrophage and lymphocyte response in Walker 256 tumor-bearing rats  

Microsoft Academic Search

Here, we investigated the effect of jump exercise on tumor growth, cancer cachexia, lymphocyte proliferation and macrophage\\u000a function in Walker 256 tumor-bearing rats. Male Wistar rats (60 days) were divided into sedentary (C) and exercised (E) groups.\\u000a Jump training consisted of six sets of 10 jumps in water with overload of 50% of body mass with 1 min of resting, four times

Carina de Lima; Luciana E. Alves; Fabíola Iagher; Andressa Franzoi Machado; Sandro J. Bonatto; Diogo Kuczera; Carine Ferreira de Souza; Daniele Cristina Pequito; Ana Lúcia Muritiba; Everson Araújo Nunes; Luiz Cláudio Fernandes

2008-01-01

289

AXR2 Encodes a Member of the Aux/IAA Protein Family1 Punita Nagpal, Loni M. Walker2  

E-print Network

AXR2 Encodes a Member of the Aux/IAA Protein Family1 Punita Nagpal, Loni M. Walker2 , Jeff C. Young, and find that it is the same as IAA7, a member of the IAA (indole-3-acetic acid) family of auxin-inducible genes. The axr2-1 mutation changes a single amino acid in conserved domain II of AXR2/IAA7. We isolated

Estelle, Mark

290

On Quantum Theory of General-Relativistic Many-Particle Systems. II ---Friedman-Robertson-Walker Universes with Quantized Matter  

Microsoft Academic Search

A formalism of quantum many-particle systems in curved spacetime is discussed in a previous paper. In the present paper, as an application of our formalism, Friedman-Robertson-Walker universes filled with quantized matter and raditation field are considered. The `temperature' of the universe will decrease inverse proportionally to the linear magnitude of the expanding universe. It becomes clear that the stress tensor

Ikuo Ichinose

1981-01-01

291

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

SciTech Connect

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.

Not Available

1993-03-01

292

Substrate recognition and processing by a Walker B mutant of the human mitochondrial AAA+ protein CLPX.  

PubMed

The mitochondrial matrix of mammalian cells contains several different ATP-dependent proteases, including CLPXP, some of which contribute to protein maturation and quality control. Currently however, the substrates and the physiological roles of mitochondrial CLPXP in humans, has remained elusive. Similarly, the mechanism by which these ATP-dependent proteases recognize their substrates currently remains unclear. Here we report the characterization of a Walker B mutation in human CLPX, in which the highly conserved glutamate was replaced with alanine. This mutant protein exhibits improved interaction with the model unfolded substrate casein and several putative physiological substrates in vitro. Although this mutant lacks ATPase activity, it retains the ability to mediate casein degradation by hCLPP, in a fashion similar to the small molecule ClpP-activator, ADEP. Our functional dissection of hCLPX structure, also identified that most model substrates are recognized by the N-terminal domain, although some substrates bypass this step and dock, directly to the pore-1 motif. Collectively these data reveal, that despite the difference between bacterial and human CLPXP complexes, human CLPXP exhibits a similar mode of substrate recognition and is deregulated by ADEPs. PMID:22710082

Lowth, Bradley R; Kirstein-Miles, Janine; Saiyed, Tamanna; Brötz-Oesterhelt, Heike; Morimoto, Richard I; Truscott, Kaye N; Dougan, David A

2012-08-01

293

Morphological descriptions on the larvae of Hypopygiopsis fumipennis (Walker, 1856) (Diptera: Calliphoridae).  

PubMed

The study on biodiversity of forensically important Diptera in the tropical rain forest in Malaysia is scarce. Thus, a preliminary survey was conducted at a jungle fringe near Kampung Bahagia Bukit Lagong, Sungai Buloh, Selangor. A rat carcass was offered to attract carrion flies and we collected an adult female calliphorid, Hypopygiopsis fumipennis (Walker, 1856) during the fresh stage of carcass decomposition. The female fly was allowed to oviposit on chicken liver in a container and the resulting larvae were reared to the adult stage. Along the developmental process, several individuals from each instar were collected and preserved in 70% ethanol and then processed on the slides. We recorded the duration of development for each instar and described its larval features for the first time. The third instar larvae of H. fumipennis showed accessory oral sclerite present, anterior spiracle with 13-15 papillae, intersegmental spines mostly unicuspid with pointed end, and posterior spiracles heavily sclerotized with inter-slit projections. Some larval differences between H. fumipennis and Hypopygiopsis violacea were noted. PMID:25801265

Heo, C C; Latif, B; Silahuddin, S A; Nazni, W A; Omar, B

2015-03-01

294

Intragenic deletion in the LARGE gene causes Walker-Warburg syndrome  

PubMed Central

Intragenic homozygous deletions in the Large gene are associated with a severe neuromuscular phenotype in the myodystrophy (myd) mouse. These mutations result in a virtual lack of glycosylation of ?-dystroglycan. Compound heterozygous LARGE mutations have been reported in a single human patient, manifesting with mild congenital muscular dystrophy (CMD) and severe mental retardation. These mutations are likely to retain some residual LARGE glycosyltransferase activity as indicated by residual ?-dystroglycan glycosylation in patient cells. We hypothesized that more severe LARGE mutations are associated with a more severe CMD phenotype in humans. Here we report a 63-kb intragenic LARGE deletion in a family with Walker-Warburg syndrome (WWS), which is characterized by CMD, and severe structural brain and eye malformations. This finding demonstrates that LARGE gene mutations can give rise to a wide clinical spectrum, similar as for other genes that have a role in the post-translational modification of the ?-dystroglycan protein. Electronic supplementary material The online version of this article (doi:10.1007/s00439-007-0362-y) contains supplementary material, which is available to authorized users. PMID:17436019

van Reeuwijk, Jeroen; Grewal, Prabhjit K.; Salih, Mustafa A. M.; Beltrán-Valero de Bernabé, Daniel; McLaughlan, Jenny M.; Michielse, Caroline B.; Herrmann, Ralf; Hewitt, Jane E.; Steinbrecher, Alice; Seidahmed, Mohamed Z.; Shaheed, Mohamed M.; Abomelha, Abdullah; Brunner, Han G.; Voit, Thomas

2007-01-01

295

A large-scale throughfall manipulation experiment on Walker Branch Watershed  

SciTech Connect

A throughfall displacement experiment is being performed in a mixed-age upland-oak forest on the upper slopes of Walker Branch Watershed in eastern Tennessee to investigate the effects of decreased and increased rainfall on individual species and ecosystem processes at the spatial scale of forest stands. Approximately 25% of the throughfall on the ``dry`` plot will be collected in polyethylene troughs suspended above the forest floor and the water transferred by gravity through pipes across the control plot for distribution onto the ``wet`` plot. Each plot is approximately 0.6 ha in size. The 25% reduction in soil moisture anticipated for the dry plot is equivalent to the driest growing season of the 1980`s drought, which was correlated with sapling mortality and reduced growth of yellow poplar on the watershed. The experimental treatments will last at least 5 years. A wide range of biological and chemical characteristics of forest stands win be investigated, including: forest growth and physiological responses of major tree and understory species, leaf area index, herbivory, litter fall, understory competition, litter decomposition, soil organic matter and microbial populations, nutrient availability, soil and soil solution chemistry, and biogeochemical cycling processes. Data on vegetation growth, mortality, and reproduction will be used in existing models of community structure to produce estimates of potential changes in species composition over longer time periods resulting from wet versus dry experimental scenarios.

Turner, R.S.; Hanson, P.J.; Huston, M.A.; Garten, C.T. Jr.; Mulholland, P.J.

1992-07-01

296

A large-scale throughfall manipulation experiment on Walker Branch Watershed  

SciTech Connect

A throughfall displacement experiment is being performed in a mixed-age upland-oak forest on the upper slopes of Walker Branch Watershed in eastern Tennessee to investigate the effects of decreased and increased rainfall on individual species and ecosystem processes at the spatial scale of forest stands. Approximately 25% of the throughfall on the dry'' plot will be collected in polyethylene troughs suspended above the forest floor and the water transferred by gravity through pipes across the control plot for distribution onto the wet'' plot. Each plot is approximately 0.6 ha in size. The 25% reduction in soil moisture anticipated for the dry plot is equivalent to the driest growing season of the 1980's drought, which was correlated with sapling mortality and reduced growth of yellow poplar on the watershed. The experimental treatments will last at least 5 years. A wide range of biological and chemical characteristics of forest stands win be investigated, including: forest growth and physiological responses of major tree and understory species, leaf area index, herbivory, litter fall, understory competition, litter decomposition, soil organic matter and microbial populations, nutrient availability, soil and soil solution chemistry, and biogeochemical cycling processes. Data on vegetation growth, mortality, and reproduction will be used in existing models of community structure to produce estimates of potential changes in species composition over longer time periods resulting from wet versus dry experimental scenarios.

Turner, R.S.; Hanson, P.J.; Huston, M.A.; Garten, C.T. Jr.; Mulholland, P.J.

1992-01-01

297

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

PubMed

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

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

298

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

299

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

PubMed

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

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

2011-01-01

300

Description and field performance of the Walker Branch throughfall displacement experiment: 1993--1996  

SciTech Connect

The authors are conducting a large-scale manipulative field experiment in an upland oak forest on the Walker Branch Watershed in eastern Tennessee to identify important ecosystem responses that might result from future precipitation changes. The manipulation of soil water content is being implemented by a gravity-driven transfer of throughfall from one 6400-m{sup 2} treatment plot to another. Throughfall is intercepted in {approx}1850 subcanopy troughs suspended above the forest floor of the dry plot and transferred by gravity flow across an ambient plot for subsequent distribution onto the wet treatment plot. Soil water content is being monitored at two depths with time domain reflectometers at 310 sampling locations across the site. The experimental system is able to produce statistically significant differences in soil water content in years having both dry and wet conditions. Maximum soil water content differentials between wet and dry plots in the 0- to 0.35-m horizon were 8 to 10% during summers with abundant precipitation and 3 to 5% during drought periods. Treatment impacts on soil water potential were restricted to the surface soil layer. Comparisons of pre- and post-installation soil and litter temperature measurements showed the ability of the experimental design to produce changes in soil water content and water potential without creating large artifacts in the forest understory environment.

Hanson, P.J.; Todd, D.E.; Huston, M.A. [Oak Ridge National lab., TN (United States). Environmental Sciences Div.; Joslin, J.D. [Tennessee Valley Authority, Norris, TN (United States); Croker, J.L.; Auge, R.M. [Univ. of Tennessee, Knoxville, TN (United States). Inst. of Agriculture

1998-04-01

301

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

SciTech Connect

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.

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

302

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

NASA Astrophysics Data System (ADS)

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.

Matyjasek, Jerzy; Sadurski, Pawe?

2013-11-01

303

Sex pheromone components of the spring hemlock looper,Lambdina athasaria (Walker) (Lepidoptera: Geometridae).  

PubMed

Two methylated hydrocarbons, 7-methylheptadecane (7) and 7,11-dimethylheptadecane (7,11), are female sex pheromone components of the spring hemlock looper (SHL),Lambdina athasaria (Walker). Compounds extracted from female pheromone glands were identified by coupled gas chromatographic-electroantennographic detection (GC-EAD) and coupled GC-mass spectrometry (GC-MS) in selected ion monitoring mode. In field trapping experiments, (7) and (7,11) by themselves were behaviorally inactive, but in combination attracted numerous male moths. (5,11)-Dimethylheptadecane (5,11) was detected in female SHL pheromone gland extracts, but did not enhance attraction to the binary blend of (7) and (7,11). The sex pheromone of SHL is related to that of congeneric eastern hemlock looper (EHL),Lambdina fiscellaria fiscellaria (Guen.) [(5,11) and 2,5-dimethylheptadecane (2,5)] and western hemlock looper (WHL),L.f. lugubrosa (Hulst) [(5,11), (2,5) and (7)]. Specificity of the pheromonal blend, spatial separation of coseasonal EHL and WHL, and temporal separation of sympatric EHL and SHL contribute to reproductive isolation. PMID:24241827

Gries, R; Gries, G; Li, J; Maier, C T; Lemmon, C R; Slessor, K N

1994-10-01

304

Immature stages of Spodoptera albula (Walker) (Lepidoptera: Noctuidae): developmental parameters and host plants.  

PubMed

This study aimed to detail the temporal and morphological parameters of the immature stages of Spodoptera albula (Walker 1857) under controlled conditions (25 ± 1°C, 70 ± 10% RH and 14 hour photophase) and to gather information about their larval host plants. For this purpose, a new rearing method and artificial diet was employed and validated. The viability of the egg, larval, pupal and pre-pupal stages was 94.54, 97.33, 93.84 and 92.34%, respectively. The average duration of the egg, larval, pupal and pre-pupal stages was 4.14, 16.37, 1.69, and 9.34 days, respectively. During the larval stage, 80.85% of females and 93.99% of males passed through six and remaining through seven instars, with significant larval protandry. The larvae that developed through six and seven instars exhibited a mean growth rate of 1.58 and 1.48, respectively. Fifty five host plant species belonging to 29 families are listed. The female pupae were significantly larger, exhibiting protogyny. Both the rearing methods as well as the larval diet proved adequate, providing more detailled observations of the biological cycle, especially the larval stage, and resulting in an overall survival of almost 80%. PMID:23538960

Montezano, Débora G; Specht, Alexandre; Bortolin, Tarciso M; Fronza, Edegar; Sosa-Gómez, Daniel R; Roque-Specht, Vânia F; Pezzi, Patrícia; Luz, Priscila C; Barros, Neiva M

2013-03-01

305

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

PubMed

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

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

2004-06-22

306

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

PubMed

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

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

307

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

PubMed

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

Foster, S P

2000-03-01

308

Bubble merging in breathing DNA as a vicious walker problem in opposite potentials  

E-print Network

We investigate the coalescence of two DNA-bubbles initially located at weak domains and separated by a more stable barrier region in a designed construct of double-stranded DNA. In a continuum Fokker-Planck approach, the characteristic time for bubble coalescence and the corresponding distribution are derived, as well as the distribution of coalescence positions along the barrier. Below the melting temperature, we find a Kramers-type barrier crossing behavior, while at high temperatures, the bubble corners perform drift-diffusion towards coalescence. In the calculations, we map the bubble dynamics on the problem of two vicious walkers in opposite potentials. We also present a discrete master equation approach to the bubble coalescence problem. Numerical evaluation and stochastic simulation of the master equation show excellent agreement with the results from the continuum approach. Given that the coalesced state is thermodynamically stabilized against a state where only one or a few base pairs of the barrier region are re-established, it appears likely that this type of setup could be useful for the quantitative investigation of thermodynamic DNA stability data as well as the rate constants involved in the unzipping and zipping dynamics of DNA, in single molecule fluorescence experiments.

Jonas Nyvold Pedersen; Mikael Sonne Hansen; Tomas Novotny; Tobias Ambjornsson; Ralf Metzler

2009-06-04

309

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

PubMed Central

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

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

310

[Spectral features analysis of Pinus massoniana with pest of Dendrolimus punctatus Walker and levels detection].  

PubMed

Taking 51 field measured hyperspectral data with different pest levels in Yanping, Fujian Province as objects, the spectral reflectance and first derivative features of 4 levels of healthy, mild, moderate and severe insect pest were analyzed. On the basis of 7 detecting parameters construction, the pest level detecting models were built. The results showed that (1) the spectral reflectance of Pinus massoniana with pests were significantly lower than that of healthy state, and the higher the pest level, the lower the reflectance; (2) with the increase in pest level, the spectral reflectance curves' "green peak" and "red valley" of Pinus massoniana gradually disappeared, and the red edge was leveleds (3) the pest led to spectral "green peak" red shift, red edge position blue shift, but the changes in "red valley" and near-infrared position were complicated; (4) CARI, RES, REA and REDVI were highly relevant to pest levels, and the correlations between REP, RERVI, RENDVI and pest level were weak; (5) the multiple linear regression model with the variables of the 7 detection parameters could effectively detect the pest levels of Dendrolimus punctatus Walker, with both the estimation rate and accuracy above 0.85. PMID:23697126

Xu, Zhang-Hua; Liu, Jian; Yu, Kun-Yong; Gong, Cong-Hong; Xie, Wan-Jun; Tang, Meng-Ya; Lai, Ri-Wen; Li, Zeng-Lu

2013-02-01

311

Approximate KMS states for scalar and spinor fields in Friedmann-Robertson-Walker spacetimes  

E-print Network

We construct and discuss Hadamard states for both scalar and Dirac spinor fields in a large class of spatially flat Friedmann-Robertson-Walker spacetimes characterised by an initial phase either of exponential or of power-law expansion. The states we obtain can be interpreted as being in thermal equilibrium at the time when the scale factor a has a specific value a=a_0. In the case a_0=0, these states fulfil a strict KMS condition on the boundary of the spacetime, which is either a cosmological horizon, or a Big Bang hypersurface. Furthermore, in the conformally invariant case, they are conformal KMS states on the full spacetime. However, they provide a natural notion of an approximate KMS state also in the remaining cases, especially for massive fields. On the technical side, our results are based on a bulk-to-boundary reconstruction technique already successfully applied in the scalar case and here proven to be suitable also for spinor fields. The potential applications of the states we find range over a broad spectrum, but they appear to be suited to discuss in particular thermal phenomena such as the cosmic neutrino background or the quantum state of dark matter.

Claudio Dappiaggi; Thomas-Paul Hack; Nicola Pinamonti

2010-09-27

312

Preserving information from the beginning to the end of time in a Robertson-Walker spacetime  

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

313

POMT2 mutations cause ?-dystroglycan hypoglycosylation and Walker-Warburg syndrome  

PubMed Central

Background: Walker-Warburg syndrome (WWS) is an autosomal recessive condition characterised by congenital muscular dystrophy, structural brain defects, and eye malformations. Typical brain abnormalities are hydrocephalus, lissencephaly, agenesis of the corpus callosum, fusion of the hemispheres, cerebellar hypoplasia, and neuronal overmigration, which causes a cobblestone cortex. Ocular abnormalities include cataract, microphthalmia, buphthalmos, and Peters anomaly. WWS patients show defective O-glycosylation of ?-dystroglycan (?-DG), which plays a key role in bridging the cytoskeleton of muscle and CNS cells with extracellular matrix proteins, important for muscle integrity and neuronal migration. In 20% of the WWS patients, hypoglycosylation results from mutations in either the protein O-mannosyltransferase 1 (POMT1), fukutin, or fukutin related protein (FKRP) genes. The other genes for this highly heterogeneous disorder remain to be identified. Objective: To look for mutations in POMT2 as a cause of WWS, as both POMT1 and POMT2 are required to achieve protein O-mannosyltransferase activity. Methods: A candidate gene approach combined with homozygosity mapping. Results: Homozygosity was found for the POMT2 locus at 14q24.3 in four of 11 consanguineous WWS families. Homozygous POMT2 mutations were present in two of these families as well as in one patient from another cohort of six WWS families. Immunohistochemistry in muscle showed severely reduced levels of glycosylated ?-DG, which is consistent with the postulated role for POMT2 in the O-mannosylation pathway. Conclusions: A fourth causative gene for WWS was uncovered. These genes account for approximately one third of the WWS cases. Several more genes are anticipated, which are likely to play a role in glycosylation of ?-DG. PMID:15894594

van Reeuwijk, J; Janssen, M; van den Elzen, C; d Beltran-Valero; Sabatelli, P; Merlini, L; Boon, M; Scheffer, H; Brockington, M; Muntoni, F; Huynen, M; Verrips, A; Walsh, C; Barth, P; Brunner, H; van Bokhoven, H

2005-01-01

314

Bioactivity-guided isolation of antiplasmodial constituents from Conyza sumatrensis (Retz.) E.H. Walker.  

PubMed

Conyza sumatrensis (Retz.) E.H. Walker (Cs) leaves are used for traditional treatment of malaria in Cameroon. However, the antimalarial activity of the leaf constituents of this plant is still unexplored. The aim of our investigation was to evaluate the antiplasmodial activity of some bioactive constituents from Cs leaves. Compounds were isolated from Cs leaves and structurally elucidated using extensive spectroscopic analysis. The in vitro antiplasmodial activity of the extracts and pure compounds were evaluated on chloroquine-sensitive strain (NF54) of Plasmodium falciparum. The in vivo assay was done by administering seven doses of extracts in mice infected with Plasmodium berghei K173 through oral route. Cytotoxicity of pure compounds on murine macrophage cells was performed through [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] (MTT) test. Hemolysis and lactate dehydrogenase assays were also carried out using standard procedures. The in silico prediction of bioactive constituents was performed through Autodock Vina. Polarity-based extracts from Cs were found to be active against P. falciparum (NF54) and P. berghei (K173) in vitro and in vivo respectively. Further, bioactivity-guided isolation of n-hexane fraction yielded three compounds, (1), (2) and (3) with IC50 of 34, 17.9 and 18?g/ml, respectively, while the ethyl acetate fraction afforded the fourth compound with an IC50 of 25?g/ml, indicating anti-malarial potential of Cs through PfLDH interaction without compromising normal cell growth. This study reports for the first time, the antiplasmodial activity of bioactive constituents from Cs and confirms its traditional use. PMID:25449289

Boniface, Pone Kamdem; Verma, Surjeet; Shukla, Aparna; Cheema, Harveer Singh; Srivastava, Santosh Kumar; Khan, Feroz; Darokar, Mahendra Pandurang; Pal, Anirban

2015-02-01

315

Characterization and Comparative Profiling of MicroRNAs in a Sexual Dimorphism Insect, Eupolyphaga sinensis Walker  

PubMed Central

Background MicroRNAs are now recognized as key post-transcriptional regulators in animal ontogenesis and phenotypic diversity. Eupolyphaga sinensis Walker (Blattaria) is a sexually dimorphic insect, which is also an important source of material used in traditional Chinese medicine. The male E. sinensis have shorter lifecycles and go through fewer instars than the female. Furthermore, the males have forewings, while the females are totally wingless. Results We used the Illumina/Solexa deep sequencing technology to sequence small RNA libraries prepared from the fourth-instar larvae of male and female E. sinensis. 19,097,799 raw reads were yielded in total: 7,817,445 reads from the female library and 11,280,354 from the male, respectively. As a result, we identified 168 known miRNAs belonging to 55 families as well as 204 novel miRNAs. Moreover, 45 miRNAs showed significantly different expression between the female and the male fourth-instar larvae, and we validated 10 of them by Stem-loop qRT-PCR. Some of these differentially expressed miRNAs are related to metamorphosis, development and phenotypic diversity. Conclusions/Significance This is the first comprehensive description of miRNAs in E. sinensis. The results provide a useful resource for further in-depth study on molecular regulation and evolution of miRNAs. These findings not only enrich miRNAs for hemimetabolans but also lay the foundation for the study of post-transcriptional regulation on the phenomena of sexual dimorphism. PMID:23620723

Li, Chengjun; Wang, Yanyun; Sang, Ming; Zhang, Yi; Li, Bin

2013-01-01

316

Twenty-year changes in biomass and nutrient distribution in forests of Walker Branch Watershed, Tennessee  

SciTech Connect

Changes in biomass and nutrient distribution in forests of Walker Branch Watershed from 1967 to 1987 are reviewed. There have been major changes in species composition in certain forest types: yellow-poplar (Liriodendron tulipifera) has largely been replaced by shortleaf pine (Pinus echinata) in what was formerly the pine forest type, and chestnut oak (Quercus prinus) appears to be replacing hickory in the oak-hickory forest type. In both cases, insect attacks (bark beetles and borers) precipitated the changes by inducing heavy mortality in native pines and hickory species in the 1970s. Subsoil (Bt horizon) exchangeable Ca/sup 2 +/ and Mg/sup 2 +/ have decreased markedly over a period of only 11 years in certain poor, upper-slope stands with oak and oak-hickory vegetation. From nutrient flux and mass balance analyses, we conclude that the Ca/sup 2 +/ changes can be attributed primarily to the sequestering of calcium in biomass. The situation with respect to Mg/sup 2 +/ is less clear; leaching was low relative to uptake in the one plot where Mg/sup 2 +/ decreases were statistically significant (95% level, t-test), yet it was clearly the dominant mechanism of Mg/sup 2 +/ export in all other plots where less significant (85% level, t-test) decreases were noted. It is noteworthy that leaching is dominated by SO/sub 4//sup 2/minus//, implying that acid deposition may be a major cause of the subsoil exchangeable Mg/sup 2 +/ decreases in some cases. 31 refs., 11 figs., 3 tabs.

Johnson, D.W.; Olson, R.J.; Mann, L.K.; Todd, D.E.

1988-01-01

317

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

PubMed

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

Yang, Linlin; Wang, Shuxia; Li, Houhun

2014-01-01

318

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

PubMed Central

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

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

1975-01-01

319

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

E-print Network

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.

Robert C. Fletcher

2013-07-22

320

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

SciTech Connect

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.

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

1993-04-01

321

Effectiveness of Removable Walker Cast Versus Nonremovable Fiberglass Off-Bearing Cast in the Healing of Diabetic Plantar Foot Ulcer  

PubMed Central

OBJECTIVE To evaluate the efficacy of a removable cast walker compared with that of a nonremovable fiberglass off-bearing cast in the treatment of diabetic plantar foot ulcer. RESEARCH DESIGN AND METHODS Forty-five adult diabetic patients with nonischemic, noninfected neuropathic plantar ulcer were randomly assigned for treatment with a nonremovable fiberglass off-bearing cast (total contact cast [TCC] group) or walker cast (Stabil-D group). Treatment duration was 90 days. Percent reduction in ulcer surface area and total healing rates were evaluated after treatment. RESULTS A total of 48 patients were screened; however, 2 patients in the TCC group and 1 patient in the Stabil-D group did not complete the study and were considered dropouts. There were no significant differences in demographic and clinic characteristics of the 45 patients completing the study. Ulcer surface decreased from 1.41 to 0.21 cm2 (P < 0.001) in the TCC group and from 2.18 to 0.45 cm2 (P < 0.001) in the Stabil-D group, with no significant differences between groups (P = 0.722). Seventeen patients (73.9%) in the TCC group and 16 patients (72.7%) in the Stabil-D group achieved healing (P = 0.794). Average healing time was 35.3 ± 3.1 and 39.7 ± 4.2 days in the TCC and Stabil-D group, respectively (P = 0.708). CONCLUSIONS The Stabil-D cast walker, although removable, was equivalent in efficacy to the TCC in terms of ulcer size reduction and total healing rate. The easier use of Stabil-D may help increase the use of off-loading devices in the management of plantar neuropathic diabetic foot ulcers. PMID:20357377

Faglia, Ezio; Caravaggi, Carlo; Clerici, Giacomo; Sganzaroli, Adriana; Curci, Vincenzo; Vailati, Wanda; Simonetti, Daniele; Sommalvico, Francesco

2010-01-01

322

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

NASA Technical Reports Server (NTRS)

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.

Robertson, Franklin; Bosilovich, Michael; Miller, Timothy

2007-01-01

323

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

SciTech Connect

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.

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

324

Epidemic modeling with discrete-space scheduled walkers: extensions and research opportunities  

PubMed Central

Background This exploratory paper outlines an epidemic simulator built on an agent-based, data-driven model of the spread of a disease within an urban environment. An intent of the model is to provide insight into how a disease may reach a tipping point, spreading to an epidemic of uncontrollable proportions. Methods As a complement to analytical methods, simulation is arguably an effective means of gaining a better understanding of system-level disease dynamics within a population and offers greater utility in its modeling capabilities. Our investigation is based on this conjecture, supported by data-driven models that are reasonable, realistic and practical, in an attempt to demonstrate their efficacy in studying system-wide epidemic phenomena. An agent-based model (ABM) offers considerable flexibility in extending the study of the phenomena before, during and after an outbreak or catastrophe. Results An agent-based model was developed based on a paradigm of a 'discrete-space scheduled walker' (DSSW), modeling a medium-sized North American City of 650,000 discrete agents, built upon a conceptual framework of statistical reasoning (law of large numbers, statistical mechanics) as well as a correct-by-construction bias. The model addresses where, who, when and what elements, corresponding to network topography and agent characteristics, behaviours, and interactions upon that topography. The DSSW-ABM has an interface and associated scripts that allow for a variety of what-if scenarios modeling disease spread throughout the population, and for data to be collected and displayed via a web browser. Conclusion This exploratory paper also presents several research opportunities for exploiting data sources of a non-obvious and disparate nature for the purposes of epidemic modeling. There is an increasing amount and variety of data that will continue to contribute to the accuracy of agent-based models and improve their utility in modeling disease spread. The model developed here is well suited to diseases where there is not a predisposition for contraction within the population. One of the advantages of agent-based modeling is the ability to set up a rare event and develop policy as to how one may mitigate damages arising from it. PMID:19922684

2009-01-01

325

Buses, Cars, Bicycles and Walkers: The Influence of the Type of Human Transport on the Flight Responses of Waterbirds  

PubMed Central

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

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

2013-01-01

326

Sensitivity of convectively coupled modes to basic state: implication to the Madden-Julian Oscillation under the Walker circulation  

NASA Astrophysics Data System (ADS)

Convectively coupled, tropical low-frequency distrubances are examined by means of eigenanalysis to the linear dynamical operator based on a T21 multilevel primitive model that involves cumulus convetions and surface heat fluxes. With relevant dissipation terms and an adjustment scheme employed to parameterize the convections, no unstable mode emerges while some of the eigenmodes show decay timescale longer than the intrinsic dissipative timescale. Under the zonally unfiorm basic state, one of these less damped modes has a zonal wavenumber 1 structure with the period of 34dy, which may be considered as a prototype of the Madden-Julian Oscillation (MJO). While a forced Kelvin wave prevails on the equator in this mode, frictional convergence in the boundary layer to the east of heating appears crucial in generating the successive convective heating anomally hence slow eastward propagation of the mode. When we incorporate an idealized Walker circulation into the basic state, a similar mode is obtained with longer period and decay timescale but the structure localized over the Indian Ocean to the western Pacific. It is noteworthy that, however, the 2nd MJ mode is traced back, in the eigenspectrum, to a zonally uniform least damped mode but not to the 1st MJ mode identified under the zonal mean basic state. These results may indicate that the origin of the observed MJO resides in a zonally uniform convective mode which is modified by interacting with the mean Walker circulation, but not in zonal wavenumber 1 modes which have been discusssed in previous studies.

Watanabe, Masahiro

2003-04-01

327

Disparate requirements for the Walker A and B ATPase motifs of human RAD51D in homologous recombination.  

PubMed

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 (ICLs). 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. PMID:16717288

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

2006-01-01

328

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

SciTech Connect

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.

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

329

Not too fast, but not too slow: searching strategies to beat a majority group of interacting walkers  

E-print Network

We introduce a model of interacting random walkers on a finite one-dimensional chain with absorbing boundaries or targets at the ends. Walkers are of two types: informed particles that move ballistically towards a given target, and diffusing uniformed particles that are biased towards close informed particles. This model mimics the dynamics of animals searching for food, where an informed individual knows the location of a food target and tries to persuade close-by uninformed conspecifics to go to that target. We characterize the success of this persuasion by the first-passage probability of the uniformed particle to the target, and we interpret the speed of the informed particle as a strategic parameter that the particle tunes to maximize its success. We find that the success probability is non-monotonic, reaching its maximum at an intermediate speed that increases with the diffusing rate of the uniformed particle. When two different groups of informed particles traveling in opposite directions compete, usua...

Martinez-Garcia, Ricardo; Vazquez, Federico

2014-01-01

330

Active Transportation in Kingston, Ontario: An Analysis of Mode, Destination, Duration, and Season among Walkers and Cyclists.  

PubMed

Background: Individuals that engage in active transportation (AT) have healthier weights and fitness levels. Most AT research has focused on work- or school-based destinations. Meanwhile, little is known about the differences between individuals that engage in the most common forms of AT - walking and cycling - and how these AT patterns vary by destination, duration, and season. Methods: We recruited 1400 randomly sampled adults (350 per season) in Kingston, Ontario, Canada to complete a cross-sectional telephone survey. The survey captured the prevalence, destinations, and duration of AT, and we examined the observed differences by mode. Results: The majority (72%) of respondents were AT-users; walking constituted 93% of overall mode share. Cyclists were more likely to be male, younger, and employed than walkers. Walkers tended to access neighbourhood-based destinations, while cyclists were more likely to use AT to get to work. AT duration was comparable by mode, ranging from approximately 8-20 minutes. Overall rates of AT were lowest in the winter, but walking rates were reasonably high year-round. Conclusions: Beyond commuting to work and school, policy-makers and planners should consider the breadth of destinations accessed by different modes when aiming to increase physical activity through AT in their communities. PMID:23963692

Collins, Patricia A; Mayer, Daphne

2013-08-19

331

Flip-chip electronic system assembly process and issues for the NanoWalker: a small wireless autonomous instrumented robot  

NASA Astrophysics Data System (ADS)

The integration of complex electronic systems onto small- scale robots requires advanced assembly methods. The NanoWalker is an example of such a robot where a large amount of electronics must be embedded in the smallest possible space. To make a space-efficient implementation, electronic chips are mounted using flip chip technology on a pre-bumped flexible printed circuit (FPC). A 3D structure is obtained by mounting the FPC vertically in a triangular fashion above a tripod built with three small piezo-actuated legs used for the walking and rotational motions. Advanced computer aided design systems are used for the design and to generate manufacturing files. Unlike other commercial products such as cellular phones, watches, pagers, cameras, and disk drives that use flip chip technology to achieve the smallest form factor, the assembly process of the NanoWalker is directly dependent on other characteristics of the system. Minimization of coupling noises through proper FPC layout and die placement within temperature constraints due to the proximity of sensitive instrument was a critical factor. The effect of vibration caused by the piezo- actuators and the weight of each die were also other important issues to consider to determine the final placement in order to maintain proper sub-atomic motion behavior.

Martel, Sylvain M.; Riley, George A.; Merchant, Monisha; Hunter, Ian W.; Lafontaine, Serge

1999-08-01

332

[The evaluation of metastatic damage of the liver of the Wistar rats under conditions of spontaneous development of the Walker 256 carcinosarcoma].  

PubMed

There was held micro- and ultrastructural study of the liver of the Wistar rats in the dynamics of development of transplantable Walker 256 carcinosarcoma. The regularities of the progression of the tumor process in the form of liver metastases with appearance of intralobular metastases. In the early stages of tumor development it was marked activation of cytotoxic function of the liver with necrosis of tumor lesions accompanied by a decrease of the structural density of metastases. In advanced stages of development of the Walker 256 carcinosarcoma an estimation of parameters of tumor invasion in the liver showed an intensification of these processes with increased severity of inflammatory reactions. PMID:24772621

Kunts, T A; Efremov, A V; Ovsianko, E V; Pustovetova, M G

2014-01-01

333

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

SciTech Connect

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.

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

1999-01-01

334

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

NASA Astrophysics Data System (ADS)

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.

Donald, Jonathon

335

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 ...

336

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

337

Geometry of Harmony and Modes in Vaughan Williams' Romanza James S. Walker, Gary W. Don, Lindsey M. Gohr, and Yeng M. Chang  

E-print Network

-Major (1938­43) by Ralph Vaughan Williams, the Romanza, is one of his most popular pieces. It exhibits manyGeometry of Harmony and Modes in Vaughan Williams' Romanza James S. Walker, Gary W. Don, Lindsey M in analyzing some music by Vaughan Williams. 1.1 Introduction The third movement of the Symphony No. 5 in D

Walker, James S.

338

March 17 - 19, 2004: caBIG CDE/V Kickoff Meeting Presentation, Daniel E. Geraghty, Heather Kincaid, Derek Walker, Rahul Joshi, Robert Robbins, Mark Thornquist  

Cancer.gov

caBIG CDE/V Kickoff Me eting Presentation Fred Hutchinson Cancer Research Center caBIG CDE/V Kickoff Meeting Presentation Fred Hutchinson Cancer Research Center Daniel E. Geraghty, Heather Kincaid, Derek Walker, Rahul Joshi, Robert Robbins, Mark Thornquist.

339

Determining thermotolerance of fifth-instar Cydia pomonella (L.) (Lepidoptera: Tortricidae) and Amyelois transitella (Walker) (Lepidoptera: Pyralidae) by three different methods  

Technology Transfer Automated Retrieval System (TEKTRAN)

Thermotolerance of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), and navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), were studied using two water immersion methods and one dry heat method. The two water immersion methods were: 1) directly immersing in hot w...

340

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

Microsoft Academic Search

The effect of coconut fat (rich in medium saturated fatty acids) or fish oil (rich in -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

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

2007-01-01

341

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

E-print Network

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

Boyer, Edmond

342

Effect of gossypol and gossypol related compounds on mulberry pyralid (diaphania pyloalis walker, lepidoptera: pyralidae), a pest of the Mulberry Tree  

Technology Transfer Automated Retrieval System (TEKTRAN)

Gossypol, gossypurpurin and diaminogossypol were tested for inhibitory effects against feeding mulberry pyralid larvae (Diaphania pyloalis Walker, Lepidoptera: Pyralidae). The inclusion of very low concentrations of these compounds (10, 50 or 100 µmoles/g) in artificial diets increased the number of...

343

Severe myopia with unusual retinal anomalies and Dandy-Walker sequence in two sibs. A distinct new neuro-ocular disorder.  

PubMed

We have observed a male and a female, sibs of non-consanguineous parents, affected by severe myopia with characteristic retinal defects and Dandy-Walker variant. The peculiarity of the retinopathy consists of pathological myopia with anomalous vitreal fenestrated membranes in the retinal periphery. We suppose that these associations may configure a new genetic syndrome. PMID:23362847

de Crecchio, Giuseppe; Cennamo, Gilda; de Leeuw, Nicole; Ventruto, Maria Luisa; Lonardo, Maria Concetta; Friso, Patrizia; Ventruto, Valerio

2013-12-01

344

EXCHANGE RESONANCES IN GADOLINIUM IRON GARNET AT 24.000 MHz By S. GESCHWIND, L. R. WALKER and D. F. LINN,  

E-print Network

344 EXCHANGE RESONANCES IN GADOLINIUM IRON GARNET AT 24.000 MHz By S. GESCHWIND, L. R. WALKER and D garnet at 24 000 Mc in the vicinity of the magnetic compensation point at Tc = + 13 °C. The two modes, FÉVRIER-MARS 1959, Introduction. - The rare earth iron garnets are, strictly, systems with three

Paris-Sud XI, Université de

345

Selection and characterization of the Bacillus thuringiensis strains toxic to Spodoptera eridania (Cramer), Spodoptera cosmioides (Walker) and Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae)  

Microsoft Academic Search

Among the pests of cultivated plants, the Spodoptera species complex is one of the most important. This genus is composed of polyphagous insects that attack, among other crops, cotton, corn, soy and castor bean. In Brazil Spodoptera frugiperda has been recognized as a primary pest in cotton, and Spodoptera eridania (Cramer) and Spodoptera cosmioides (Walker) species are important pests in

Karen Bianchi dos Santos; Pedro Neves; Ana Maria Meneguim; Rachel Bianchi dos Santos; Walter Jorge dos Santos; Gislaine Villas Boas; Vinicius Dumas; Erica Martins; Lílian Botelho Praça; Paulo Queiroz; Colin Berry; Rose Monnerat

2009-01-01

346

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

E-print Network

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

Boyer, Edmond

347

AppAlAchiAn StAte UniverSity UndergrAdUAte BUlletin 2009-2010 The John A. Walker College of Business  

E-print Network

major early in their studies. Meeting graduation requirements is the student's responsibility. Degrees Offered Through the Walker College of Business, students can obtain the following degrees: 1. Bachelor for declared business majors is available through the College of Business Undergraduate Advising Office

Rose, Annkatrin

348

Leucine modulates the effect of Walker factor, a proteolysis-inducing factor-like protein from Walker tumours, on gene expression and cellular activity in C2C12 myotubes.  

PubMed

Cancer-cachexia causes severe weight loss, particularly from the wasting of skeletal muscle, which occurs due to increased protein catabolism and/or decreased protein synthesis. The muscle protein degradation observed in cancer patients is mediated by a specific cytokine, proteolysis-inducing factor (PIF), which is produced by the tumour. This protein increases the ubiquitin-proteasome pathway activity, and the synthesis of muscle protein in these patients can be affected by several factors, including nutrient-related signalling. Some nutrients, such as leucine, can decrease the ubiquitin-proteasome pathway activity and increase the skeletal muscle protein content in cachectic animals. In this study, we investigated the effects of leucine on cell viability, morphology, functional proteasome activity, enzymatic activity, and protein synthesis and degradation in C2C12 myotubes exposed to the proteolysis-inducing factor (PIF)-like protein purified from Walker tumour-bearing rats. Walker factor (WF) had no cytotoxic effects on myotube cells and morphological characteristics were not altered in the presence of WF and/or leucine. However, increased alkaline phosphatase activity was observed. At higher WF concentrations, chymotrypsin-like activity, cathepsin B activity and 20S proteasome gene expression increased. Treating myotubes with leucine before exposure to WF causes leads to a decrease in proteasome activity as well as the activity of chymotrypsin and cathepsin enzymes. Total protein synthesis decreased in WF-treated cells concomitantly as protein degradation increased. After leucine exposure, the observed effects of WF were minimal or even reverted in some cases. Taken together, these results suggest an important modulatory effect for leucine on the effects of WF in C2C12 myotube cells. PMID:23746792

Gonçalves, Estela Maria; Salomão, Emilianne Miguel; Gomes-Marcondes, Maria Cristina Cintra

2013-10-01

349

The Lame$^{\\prime}$ Equation for Distance-Redshift in Partially Filled Beam Friedmann-Lema\\^?tre-Robertson-Walker Cosmology  

E-print Network

The differential equation governing distance-redshift for partially filled-beam optics in pressure-freeFriedmann-Lema\\^\\i tre-Robertson-Walker Cosmology (FLRW) is shown to be the Lame$^{\\prime}$ equation. The distance-redshift, $D(z)$, discussed is appropriate for observations in inhomogeneous cosmologies for which lensing by masses external to the observing beam are negligible and for which lensing by transparent matter within the beam can be approximated by a homogeneous mass density expanding with the FLRW background. Some solutions of the derived Lame$^{\\prime}$ equation are given in terms of Weierstrass elliptic integrals. A new simplified and useful expression for filled-beam $D(z)$ in standard flat FLRW is also given.

R. Kantowski

2003-08-24

350

The influence of ocean surface temperature gradient and continentality on the Walker circulation. II - Prescribed global changes  

NASA Technical Reports Server (NTRS)

The series of experiments presently used to investigate the mechanisms responsible for forcing the global Walker circulation features worldwide changes in ocean surface temperatures (OSTs), topography, and/or continents. The primary factor affecting circulation is noted to be the global distribution of continents and oceans; while OST gradients are also important, topography emerges as comparatively unimportant. Continentality and OST gradients force the model atmosphere through the introduction of zonal variations in surface heating. The vertical motions to which they give rise yield moisture convergence and condensation variations which reinforce vertical motions. The forcing by OST gradients is partly nonlocal, and the atmospheric response is effected by continentality. In all cases, vertical motion zonal variations correlate with precipitation.

Stone, P. H.; Chervin, R. M.

1984-01-01

351

ISPD loss-of-function mutations disrupt dystroglycan O-mannosylation and cause Walker-Warburg syndrome  

PubMed Central

Walker-Warburg syndrome (WWS) is clinically defined as congenital muscular dystrophy accompanied by a variety of brain and eye malformations. It represents the most severe clinical phenotype in a spectrum of alpha-dystroglycan posttranslational processing abnormalities, which share a defect in laminin binding glycan synthesis1. Although six WWS causing genes have been described, only half of all patients can currently be diagnosed genetically2. A cell fusion complementation assay using fibroblasts from undiagnosed WWS individuals identified five novel complementation groups. Further evaluation of one group by linkage analysis and targeted sequencing identified recessive mutations in the isoprenoid synthase domain containing (ISPD) gene. Confirmation of the pathogenicity of the identified ISPD mutations was demonstrated by complementation of fibroblasts with wild-type ISPD. Finally, we show that recessive mutations in ISPD abolish the initial step in laminin binding glycan synthesis by disrupting dystroglycan O-mannosylation. This establishes a novel mechanism for WWS pathophysiology. PMID:22522420

Willer, Tobias; Lee, Hane; Lommel, Mark; Yoshida-Moriguchi, Takako; de Bernabe, Daniel Beltran Valero; Venzke, David; Cirak, Sebahattin; Schachter, Harry; Vajsar, Jiri; Voit, Thomas; Muntoni, Francesco; Loder, Andrea S.; Dobyns, William B.; Winder, Thomas L.; Strahl, Sabine; Mathews, Katherine D.; Nelson, Stanley F.; Moore, Steven A.; Campbell, Kevin P.

2012-01-01

352

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

SciTech Connect

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.

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

353

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

SciTech Connect

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.

Beall, J.J.

1981-10-01

354

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

SciTech Connect

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.

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

1982-05-01

355

The sexual adult of Cercaria praecox Walker, 1971 (Digenea: Fellodistomidae), with the proposal of Oceroma n. g.  

PubMed

A sexual adult trematode that is considered to be conspecific with the distinctive larval trematode Cercaria praecox Walker, 1971 is reported from the kyphosid fish Scorpis lineolata Kner in Moreton Bay, Queensland, Australia. The sexual adult is consistent with the cercarial body of Cercaria praecox in having a single caecum with an asymmetrical appendix, symmetrical testes immediately posterior to the ventral sucker, and the ovary and vitellarium both well posterior to the testes. This combination of characters is distinct within the Fellodistomidae Nicoll, 1909 and requires the proposal of a new genus, Oceroma n. g. Analysis of 28S rDNA sequences demonstrates that this species forms a clade with Coomera Dove & Cribb, 1995 within the Fellodistomidae. The life-cycle of the species is predicted to require two hosts and to involve the direct ingestion of the cercaria. PMID:24711109

Cribb, Thomas H; Miller, Terrence L; Bray, Rodney A; Cutmore, Scott C

2014-05-01

356

Unusual Ventriculoperitoneal (VP) Shunt Tube Extrusion through Anus in a Child with Dandy Walker Malformation: A Rare Case Report.  

PubMed

Aim of this paper is to report a case of extrusion of Ventriculo peritoneal shunt tube through anus in a one year female child ( k/c/o dandy walker malformation ) treated with placement of ventriculo peritoneal shunt for post operative hydrocephalus after excision of Subtorcular occipital meningocoel. The exact cause of such extrusion is not known. Unusual migration of distal catheter tip of VP shunt is a rare and bowel perforation is reported to occur between 0.1% and 0.7%. The possible factors responsible for this complication are thin bowel wall in children, sharp and stiff end of the VP shunt, use of trocar by some surgeons, chronic irritation by the shunt, previous surgery, infection and silicone allergy. In view of the potential for meningitis prompt and aggressive management is essential to avoid morbidity and mortality. PMID:25738035

Bansal, Hanish; Gupta, Gulzar; Gupta, Mayank; Kaushal, Rakesh

2015-01-01

357

An Interaction between the Walker A and D-loop Motifs Is Critical to ATP Hydrolysis and Cooperativity in Bacteriophage T4 Rad50*  

PubMed Central

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

De la Rosa, Metzere Bierlein; Nelson, Scott W.

2011-01-01

358

Latest Quaternary paleoseismology and evidence of distributed dextral shear along the Mohawk Valley fault zone, northern Walker Lane, California  

NASA Astrophysics Data System (ADS)

The dextral-slip Mohawk Valley fault zone (MVFZ) strikes northwestward along the eastern margin of the Sierra Nevada in the northern Walker Lane. Geodetic block modeling indicates that the MVFZ may accommodate ~3 mm/yr of regional dextral strain, implying that it is the highest slip-rate strike-slip fault in the region; however, only limited geologic data are available to constrain the system's slip rate and earthquake history. We mapped the MVFZ using airborne lidar data and field observations and identified a site near Sulphur Creek for paleoseismic investigation. At this site, oblique dextral-normal faulting on the steep valley margin has created a closed depression that floods annually during spring snowmelt to form an ephemeral pond. We excavated three fault-perpendicular trenches at the site and exposed pond sediment that interfingers with multiple colluvial packages eroded from the scarp that bounds the eastern side of the pond. We documented evidence for four surface-rupturing earthquakes on this strand of the MVFZ. OxCal modeling of radiocarbon and luminescence ages indicates that these earthquakes occurred at 14.0 ka, 12.8 ka, 5.7 ka, and 1.9 ka. The mean ~4 kyr recurrence interval is inconsistent with slip rates of ~3 mm/yr; these rates imply surface ruptures of more than 10 m per event, which is geologically implausible for the subdued geomorphic expression and 60 km length of the MVFZ. We propose that unidentified structures not yet incorporated into geodetic models may accommodate significant dextral shear across the northern Walker Lane, highlighting the role of distributed deformation in this region.

Gold, Ryan D.; Briggs, Richard W.; Personius, Stephen F.; Crone, Anthony J.; Mahan, Shannon A.; Angster, Stephen J.

2014-06-01

359

The application of active-source seismic imaging techniques to transtensional problems the Walker Lane and Salton Trough  

NASA Astrophysics Data System (ADS)

The plate margin in the western United States is an active tectonic region that contains the integrated deformation between the North American and Pacific plates. Nearly focused plate motion between the North American and Pacific plates within the northern Gulf of California gives way north of the Salton Trough to more diffuse deformation. In particular a large fraction of the slip along the southernmost San Andreas fault ultimately bleeds eastward, including about 20% of the total plate motion budget that finds its way through the transtensional Walker Lane Deformation Belt just east of the Sierra Nevada mountain range. Fault-bounded ranges combined with intervening low-lying basins characterize this region; the down-dropped features are often filled with water, which present opportunities for seismic imaging at unprecedented scales. Here I present active-source seismic imaging from the Salton Sea and Walker Lane Deformation Belt, including both marine applications in lakes and shallow seas, and more conventional land-based techniques along the Carson range front. The complex fault network beneath the Salton Trough in eastern California is the on-land continuation of the Gulf of California rift system, where North American-Pacific plate motion is accommodated by a series of long transform faults, separated by small pull-apart, transtensional basins; the right-lateral San Andreas fault bounds this system to the north where it carries, on average, about 50% of total plate motion. The Salton Sea resides within the most youthful and northerly "spreading center" in this several thousand-kilometer-long rift system. The Sea provides an ideal environment for the use of high-data-density marine seismic techniques. Two active-source seismic campaigns in 2010 and 2011 show progression of the development of the Salton pull-apart sub-basin and the northerly propagation of the Imperial-San Andreas system through time at varying resolutions. High fidelity seismic imagery documents the timing of strain transfer from the Imperial fault onto the San Andreas fault through the application of sequence stratigraphy. Evidence shows that the formation of the Salton and Mesquite sub-basins and the associated change of strain partitioning occurred within the last 20-40 k.y., essentially modifying a broader zone of transtension bounding the Imperial and San Andreas faults into two smaller zones of focused extension. The north-central Walker Lane contains a diffuse network of both strike-slip and normal faults, with some degree of strain partitioning characterized by normal faulting to the west along the eastern edge of the Sierra Nevada mountain range, and strike-slip faults to the east that define a diffuse boundary against the Basin and Range proper. A seismic study across the Mount Rose fault zone, bounding the Carson Range near Reno, Nevada, was carried out to investigate slip across a potential low-angle normal fault. A hammer seismic reflection and refraction profile combined with airborne LiDAR (light detection and ranging) imagery highlights fault scarp modification through minor slumping/landslides, providing a better understanding of the nature of slip on this fault. The northeastern margin of the Walker Lane is a region where both "Basin and Range" style normal faults and dextral strike-slip faults contribute to the northward propagation of the Walker Lane (essentially parallel to an equivalent northward propagation of the Mendocino triple junction). Near this intersection lies Pyramid Lake, bounded to the southwest by the dextral Pyramid Lake fault and to the northeast by the normal Lake Range fault. A high-resolution (sub-meter) seismic CHIRP survey collected in 2010 shows intriguing relationships into fault architecture beneath Pyramid Lake. Over 500 line-km of seismic data reveal a polarity flip in basin structure as down-to-the-east motion at the northern end of the Pyramid Lake fault rapidly gives way to down-to-the-west normal motion along the Lake Range fault. Alternating patterns of asymmetric and symmetric

Kell, Anna Marie

360

Similar and Contrasting Response of Rifting and Transtension in the Gulf of California and Walker Lane to Preceding Arc Magmatism  

NASA Astrophysics Data System (ADS)

The Gulf of California (GC) and Walker Lane (WL) have undergone strikingly similar development with strike- slip faulting following initial extension. They differ significantly in the amount of Pacific-North American plate motion taken up by each: essentially all relative motion in the GC and ~25% in the WL. In both areas, ancestral arc magmatism preceded and probably focused deformation, perhaps because heating and/or hydration weakened the lithosphere. However, differences in migration of the Rivera (RTJ) and Mendocino triple junctions (MTJ) related to differences in the orientation of plate boundaries determined how strike-slip faulting developed. Abrupt southward jumps in the RTJ led to abrupt cessation of magmatism over arc lengths of as much as 1000 km and initiation of east-northeast extension within the future GC. The best known jump was at ~13 Ma, but an earlier jump occurred at ~18 Ma. Arc magmatism has been best documented in Baja California, Sonora, and Nayarit, although Baja constituted the most-trenchward fringe of the ancestral arc. New and published data indicate that Sinaloa underwent a similar history of arc magmatism. The greatest volume of the arc immediately preceding RTJ jumps was probably in mainland Mexico. Arc magmatism shut off following these jumps, extension began in the future GC, and strike-slip faulting either followed or accompanied extension in the GC. In contrast, the MTJ migrated progressively northward. New and published data indicate magmatism generally shut off coincident with this retreat, but distinct nodes or zones of magmatism, presumably unrelated to subduction, persisted or initiated after arc activity ceased. We have suggested that the WL has grown progressively northward, following the retreating arc, and that the northern WL is its youngest part. However, the timing of initiation of strike-slip faulting in most of the WL is poorly known and controversial. Testing our hypothesis requires determining initiation and magnitudes of total slip across different parts. Despite the progressive migration of the MTJ, arc magmatism ceased abruptly at the latitude of Lake Tahoe (39.2°) at about 3 Ma, and the southern end of the active Cascade arc jumped ~160 km northward to Lassen Peak (40.5°), where it remains. Geologic data indicate strike-slip faulting began between these two areas immediately following the end of arc magmatism. The southern Cascade arc is undergoing ~east-west extension, which was the case for the northern Walker Lane immediately before strike-slip faulting began. Further progression or steps in magmatism and strike-slip faulting will likely follow further northward migration of the MTJ.

Henry, C. D.; Faulds, J. E.

2006-12-01

361

Changes in energy cost and total external work of muscles in elite race walkers walking at different speeds.  

PubMed

The aim of the study was to assess energy cost and total external work (total energy) depending on the speed of race walking. Another objective was to determine the contribution of external work to total energy cost of walking at technical, threshold and racing speed in elite competitive race walkers. The study involved 12 competitive race walkers aged 24.9 4.10 years with 6 to 20 years of experience, who achieved a national or international sports level. Their aerobic endurance was determined by means of a direct method involving an incremental exercise test on the treadmill. The participants performed three tests walking each time with one of the three speeds according to the same protocol: an 8-minute walk with at steady speed was followed by a recovery phase until the oxygen debt was repaid. To measure exercise energy cost, an indirect method based on the volume of oxygen uptake was employed. The gait of the participants was recorded using the 3D Vicon opto-electronic motion capture system. Values of changes in potential energy and total kinetic energy in a gate cycle were determined based on vertical displacements of the centre of mass. Changes in mechanical energy amounted to the value of total external work of muscles needed to accelerate and lift the centre of mass during a normalised gait cycle. The values of average energy cost and of total external work standardised to body mass and distance covered calculated for technical speed, threshold and racing speeds turned out to be statistically significant (p 0.001). The total energy cost ranged from 51.2 kJ.m-1 during walking at technical speed to 78.3 kJ.m-1 during walking at a racing speed. Regardless of the type of speed, the total external work of muscles accounted for around 25% of total energy cost in race walking. Total external work mainly increased because of changes in the resultant kinetic energy of the centre of mass movement. PMID:25713673

Chwa?a, Wies?aw; Klimek, Andrzej; Mirek, Wac?aw

2014-12-01

362

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

E-print Network

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 T� other people who may collect you child please list anyone who is forbidden to have access to your child

Hickman, Mark

363

Theory of the transmission of infection in the spread of epidemics: interacting random walkers with and without confinement.  

PubMed

A theory of the spread of epidemics is formulated on the basis of pairwise interactions in a dilute system of random walkers (infected and susceptible animals) moving in [Formula: see text] dimensions. The motion of an animal pair is taken to obey a Smoluchowski equation in [Formula: see text]-dimensional space that combines diffusion with confinement of each animal to its particular home range. An additional (reaction) term that comes into play when the animals are in close proximity describes the process of infection. Analytic solutions are obtained, confirmed by numerical procedures, and shown to predict a surprising effect of confinement. The effect is that infection spread has a non-monotonic dependence on the diffusion constant and/or the extent of the attachment of the animals to the home ranges. Optimum values of these parameters exist for any given distance between the attractive centers. Any change from those values, involving faster/slower diffusion or shallower/steeper confinement, hinders the transmission of infection. A physical explanation is provided by the theory. Reduction to the simpler case of no home ranges is demonstrated. Effective infection rates are calculated, and it is shown how to use them in complex systems consisting of dense populations. PMID:25403272

Kenkre, V M; Sugaya, S

2014-12-01

364

Effects of Fraxinellone on the Midgut Enzyme Activities of the 5th Instar Larvae of Oriental Armyworm, Mythimna separata Walker  

PubMed Central

Isolated from Dictamnus dasycarpus Turcz., fraxinellone exhibited multiple bioactivities against insects. In the present paper, the changes of digestive enzymes and detoxification enzymes of Mythimna separata Walker (5th instar larvae), treated with fraxinellone, were investigated. Compared with those of the control, the ?-amylase activity of the fraxinellone-treated 5th instar larvae was inhibited, whereas the level of their protease activity was increased. Based upon further studies on the specific proteases, the levels of the active alkaline trypsin-like enzyme (BApNA as the substrate) and the chymotrypsin-like enzyme (BTEE as the substrate) activities of the treated larvae were declined; however, the level of activity of the weak alkaline trypsin-like enzyme (TAME as the substrate) of the treated ones was increased. Meanwhile, the activities of two detoxification enzymes, such as carboxylesterase (CarE) and glutathione S-transferase (GST), of the treated larvae were increased to some extent, but the activities of NADPH-P450 reductase and O-demethylase of the treated ones declined. Therefore, protease (especially the weak alkaline trypsin-like enzyme), CarE and GST played important roles in the metabolism of fraxinellone in the midgut of Mythimna separata (M. separata). PMID:25216084

Lv, Min; Wu, Wenjun; Liu, Huixia

2014-01-01

365

ISPD loss-of-function mutations disrupt dystroglycan O-mannosylation and cause Walker-Warburg syndrome.  

PubMed

Walker-Warburg syndrome (WWS) is clinically defined as congenital muscular dystrophy that is accompanied by a variety of brain and eye malformations. It represents the most severe clinical phenotype in a spectrum of diseases associated with abnormal post-translational processing of a-dystroglycan that share a defect in laminin-binding glycan synthesis1. Although mutations in six genes have been identified as causes of WWS, only half of all individuals with the disease can currently be diagnosed on this basis2. A cell fusion complementation assay in fibroblasts from undiagnosed individuals with WWS was used to identify five new complementation groups. Further evaluation of one group by linkage analysis and targeted sequencing identified recessive mutations in the ISPD gene (encoding isoprenoid synthase domain containing). The pathogenicity of the identified ISPD mutations was shown by complementation of fibroblasts with wild-type ISPD. Finally, we show that recessive mutations in ISPD abolish the initial step in laminin-binding glycan synthesis by disrupting dystroglycan O-mannosylation. This establishes a new mechanism for WWS pathophysiology. PMID:22522420

Willer, Tobias; Lee, Hane; Lommel, Mark; Yoshida-Moriguchi, Takako; de Bernabe, Daniel Beltran Valero; Venzke, David; Cirak, Sebahattin; Schachter, Harry; Vajsar, Jiri; Voit, Thomas; Muntoni, Francesco; Loder, Andrea S; Dobyns, William B; Winder, Thomas L; Strahl, Sabine; Mathews, Katherine D; Nelson, Stanley F; Moore, Steven A; Campbell, Kevin P

2012-05-01

366

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

PubMed Central

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

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

2012-01-01

367

Approximation methods in Loop Quantum Cosmology: From Gowdy cosmologies to inhomogeneous models in Friedmann-Robertson-Walker geometries  

E-print Network

We develop approximation methods in the hybrid quantization of the Gowdy model with linear polarization and a massless scalar field, for the case of three-torus spatial topology. The loop quantization of the homogeneous gravitational sector of the Gowdy model (according to the improved dynamics prescription) and the presence of inhomogeneities lead to a very complicated Hamiltonian constraint. Therefore, the extraction of physical results calls for the introduction of well justified approximations. We first show how to approximate the homogeneous part of the Hamiltonian constraint, corresponding to Bianchi I geometries, as if it described a Friedmann-Robertson-Walker (FRW) model corrected with anisotropies. This approximation is valid in the high-energy sector of the FRW geometry (concerning its contribution to the constraint) and for anisotropy profiles that are sufficiently smooth. In addition, for certain families of states associated to regimes of physical interest, with negligible effects of the anisotropies and small inhomogeneities, one can approximate the Hamiltonian constraint of the inhomogeneous system by that of an FRW geometry with a relatively simple matter content, and then obtain its solutions.

Mercedes Martín-Benito; Daniel Martín-de Blas; Guillermo A. Mena Marugán

2014-11-28

368

Replacement by Caenis diminuta walker (ephemeroptera:caenidae) in the mayfly community structure of a thermally-stressed, southeastern stream  

SciTech Connect

Mayfly community structure on sycamore and sweetgum leaf packs in a thermally-stressed, post-thermal and an unstressed stream were compared. Leaves were colonized over an 11 wk (77 d) period from December 1982 to March 1983. Degree-days (> 0/sup 0/C) accumulated were 1014, 638 and 627 for the thermally-stressed, post-thermal and unstressed streams, respectively. Significant differences in mayfly community structure were found between the thermally-stressed vs. the post-thermal and unstressed streams with respect to both Stenonema spp. and Caenis diminuta Walker. No significant differences in community structure were found between the two leaf species. Stenonema spp. dominated the mayfly fauna over the sampling period for both the unstressed (68%) and post-thermal (98%) streams; however, C. diminuta replaced Stenonema spp. as the dominant mayfly (88%) within leaf packs from the stream receiving thermal effluent. Additional data suggest C. diminuta is tolerant of rapidly fluctuating thermal regimes (..delta.. T of up to 11/sup 0/C in 1 h) and high temperatures (up to 40/sup 0/C). 30 references, 3 figures, 3 tables.

Poff, N L; Matthews, R A

1984-01-01

369

Theory of the Transmission of Infection in the Spread of Epidemics: Interacting Random Walkers with and without Confinement  

E-print Network

A theory of the spread of epidemics is formulated on the basis of pairwise interactions in a dilute system of random walkers (infected and susceptible animals) moving in n dimensions. The motion of an animal pair is taken to obey a Smoluchowski equation in 2n-dimensional space that combines diffusion with confinement of each animal to its particular home range. An additional (reaction) term that comes into play when the animals are in close proximity describes the process of infection. Analytic solutions are obtained, confirmed by numerical procedures, and shown to predict a surprising effect of confinement. The effect is that infection spread has a non-monotonic dependence on the diffusion constant and/or the extent of the attachment of the animals to the home ranges. Optimum values of these parameters exist for any given distance between the attractive centers. Any change from those values, involving faster/slower diffusion or shallower/steeper confinement, hinders the transmission of infection. A physical ...

Kenkre, V M

2014-01-01

370

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

PubMed Central

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

Lu, Lina; Qi, Zhijun; Wu, Wenjun

2014-01-01

371

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

PubMed

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

Doolin, Ciaran; Neupane, Ishwaree P

2013-04-01

372

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

SciTech Connect

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.

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

373

Engineering sugarcane cultivars with bovine pancreatic trypsin inhibitor (aprotinin) gene for protection against top borer (Scirpophaga excerptalis Walker).  

PubMed

The inhibitory activity of bovine pancreatic trypsin inhibitor (aprotinin), a natural polypeptide and a proteinase inhibitor, was demonstrated on gut proteinases of three lepidopteran borers of sugarcane using commercially available aprotinin. A synthetic gene coding for aprotinin, designed and codon optimized for better expression in plant system (Shantaram 1999), was transferred to two sugarcane cultivars namely CoC 92061 and Co 86032 through particle bombardment. Aprotinin gene expression was driven by maize ubiquitin promoter and the plant selection marker used was hygromycin resistance. The integration, expression and functionality of the transgene was confirmed by Southern, Western and insect bioassay, respectively. Southern analysis showed two to four integration sites of the transgene in the transformed plants. Independent transgenic events showed varied levels of transgene expression resulting in different levels (0.16-0.50%) of aprotinin. In in vivo bioassay studies, larvae of top borer Scirpophaga excerptalis Walker (Lepidoptera: Pyralidae) fed on transgenics showed significant reduction in larval weight which indicated impairment of their development. Results of this study show the possibility of deploying aprotinin gene for the development of transgenic sugarcane cultivars resistant to top borer. PMID:18985354

Christy, Leela Amala; Arvinth, S; Saravanakumar, M; Kanchana, M; Mukunthan, N; Srikanth, J; Thomas, George; Subramonian, N

2009-02-01

374

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

PubMed

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

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

2002-04-01

375

Spatial and temporal variability in faulting along a Quaternary fault transect across the Northern Walker Lane, California-Nevada  

NASA Astrophysics Data System (ADS)

What are the temporal and spatial patterns of faulting across shear zones with overlapping parallel faults that are preferentially oriented to accommodate regional shear? How should earthquake hazard be modeled if these systems have variable earthquake recurrence? We explore these questions in the Northern Walker Lane, a 100-km-wide zone of dextral shear along the eastern side of the Sierra Nevada, which accommodates ~15% of the 50 mm/yr of relative motion between the Pacific and North American plates. We used high-resolution airborne Light Distance and Ranging (LiDAR) data to create surficial geologic maps, conducted paleoseismic trenching, applied Quaternary geochronology, and collected high-resolution seismic-reflection profiles along a fault-perpendicular transect across the principal, subparallel, northwest-striking Mohawk Valley, Grizzly Valley, Honey Lake, and Warm Springs Valley dextral-slip faults. Key results along this transect from southwest-to-northeast are: (1) trenching at the Sulphur Creek Sidehill Bench site on the Mohawk Valley fault system indicates four surface-rupturing earthquakes since ~14 ka, which is fewer events than inferred from the slip rate of 2.9 mm/yr from geodetic block-models. To reconcile these results, we suggest that strain is widely distributed on numerous uncharacterized fault strands or that the contemporary (geodetic block model) rate is a young phenomena and hasn't been sustained since 14 ka. (2) High-resolution shallow seismic-reflection imaging and topographic analysis using the LiDAR data provide the first conclusive evidence that the Grizzly Valley fault system is an active Quaternary structure, with probable motion in the latest Quaternary. This result is significant because this fault system is not presently included in the USGS Quaternary fault-and-fold database, is not specified as a seismic source in most regional hazard models, and is also not defined as a boundary in regional geodetic block models. (3) New analysis of faulted, post-Lahontan fluvial terrace risers along the Honey Lake fault system suggests an average slip rate of 2.3 mm/yr since 15.8 ka, but the rate may have slowed to 1.3 mm/yr since the mid Holocene. The latter rate is consistent with geodetic block models. (4) A late Quaternary slip record for the Warm Springs Valley fault system suggests that, the fault had a slip rate of 2.5-3.8 mm/yr from ~50-15 ka, but since 15.8 ka, the rate has been <0.2 mm/yr. We speculate that the slip-rate variability may be linked to co-varying slip with the overlapping and adjacent Honey Lake fault, but additional late Quaternary slip-rate data are needed for the Honey Lake fault to test this hypothesis. In summary, the results along this transect led to identification of new, active Quaternary faults and revealed evidence for spatial and temporal slip-rate variability on parallel and overlapping strike-slip faults in the Northern Walker Lane. We propose that the recognition of new active structures and temporal variations in slip rates may help explain discrepancies between long-term geologic and modern geodetic slip rates across this region. We now need to determine whether a long-term slip rate or the recent record of the last few thousand years is most representative of a fault's near-term earthquake potential.

Gold, R. D.; Briggs, R. W.; Crone, A. J.

2013-12-01

376

A Deletion in the VLDLR Gene in Eurasier Dogs with Cerebellar Hypoplasia Resembling a Dandy-Walker-Like Malformation (DWLM)  

PubMed Central

Dandy-Walker-like malformation (DWLM) is the result of aberrant brain development and mainly characterized by cerebellar hypoplasia. DWLM affected dogs display a non-progressive cerebellar ataxia. Several DWLM cases were recently observed in the Eurasier dog breed, which strongly suggested a monogenic autosomal recessive inheritance in this breed. We performed a genome-wide association study (GWAS) with 9 cases and 11 controls and found the best association of DWLM with markers on chromosome 1. Subsequent homozygosity mapping confirmed that all 9 cases were homozygous for a shared haplotype in this region, which delineated a critical interval of 3.35 Mb. We sequenced the genome of an affected Eurasier and compared it with the Boxer reference genome and 47 control genomes of dogs from other breeds. This analysis revealed 4 private non-synonymous variants in the critical interval of the affected Eurasier. We genotyped these variants in additional dogs and found perfect association for only one of these variants, a single base deletion in the VLDLR gene encoding the very low density lipoprotein receptor. This variant, VLDLR:c.1713delC is predicted to cause a frameshift and premature stop codon (p.W572Gfs*10). Variants in the VLDLR gene have been shown to cause congenital cerebellar ataxia and mental retardation in human patients and Vldlr knockout mice also display an ataxia phenotype. Our combined genetic data together with the functional knowledge on the VLDLR gene from other species thus strongly suggest that VLDLR:c.1713delC is indeed causing DWLM in Eurasier dogs. PMID:25668033

Gerber, Martina; Fischer, Andrea; Jagannathan, Vidhya; Drögemüller, Michaela; Drögemüller, Cord; Schmidt, Martin J.; Bernardino, Filipa; Manz, Eberhard; Matiasek, Kaspar; Rentmeister, Kai; Leeb, Tosso

2015-01-01

377

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

SciTech Connect

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.

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

2007-01-01

378

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

USGS Publications Warehouse

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.

Williams, A. Park; Funk, Chris

2011-01-01

379

Mortality of Dandy-Walker syndrome in the United States: Analysis by race, gender, and insurance status  

PubMed Central

Background: Dandy-Walker syndrome (DWS) is a congenital disorder often diagnosed in early childhood. Typically manifesting with signs/symptoms of increased intracranial pressure, DWS is catastrophic unless timely neurosurgical care can be administered via cerebrospinal fluid (CSF) drainage. The rates of mortality, adverse discharge disposition (ADD), and CSF drainage in DWS may not be uniform regardless of race, gender or insurance status; such differences could reflect disparities in access to neurosurgical care. This study examines these issues on a nationwide level. Materials and Methods: The Kids’ Inpatient Database spanning 1997-2003 was used for analysis. Only patients admitted for DWS (ICD-9-CM = 742.3) were included. Multivariate analysis was adjusted for several variables, including patient age, race, sex, admission type, primary payer, income, and hospital volume. Results: More than 14,000 DWS patients were included. Increasing age predicted reduced mortality (OR = 0.87; P < 0.05), ADD (OR = 0.96; P < 0.05), and decreased likelihood of receiving CSF drainage (OR = 0.86; P < 0.0001). Elective admission type predicted reduced mortality (OR = 0.29; P = 0.0008), ADD (OR = 0.68; P < 0.05), and increased CSF drainage (OR = 2.02; P < 0.0001). African-American race (OR = 1.20; P < 0.05) and private insurance (OR = 1.18; P < 0.05) each predicted increased likelihood of receiving CSF drainage, but were not predictors of mortality or ADD. Gender, income, and hospital volume were not significant predictors of DWS outcome. Conclusion: Increasing age and elective admissions each decrease mortality and ADD associated with DWS. African-American race and private insurance status increase access to CSF drainage. These findings contradict previous literature citing African-American race as a risk factor for mortality in DWS, and emphasize the role of private insurance in obtaining access to potentially lifesaving operative care.

McClelland, Shearwood; Ukwuoma, Onyinyechi I.; Lunos, Scott; Okuyemi, Kolawole S.

2015-01-01

380

Late quaternary slip-rate variations along the Warm Springs Valley fault system, northern Walker Lane, California-Nevada border  

USGS Publications Warehouse

The extent to which faults exhibit temporally varying slip rates has important consequences for models of fault mechanics and probabilistic seismic hazard. Here, we explore the temporal behavior of the dextral?slip Warm Springs Valley fault system, which is part of a network of closely spaced (10–20 km) faults in the northern Walker Lane (California–Nevada border). We develop a late Quaternary slip record for the fault using Quaternary mapping and high?resolution topographic data from airborne Light Distance and Ranging (LiDAR). The faulted Fort Sage alluvial fan (40.06° N, 119.99° W) is dextrally displaced 98+42/-43 m, and we estimate the age of the alluvial fan to be 41.4+10.0/-4.8 to 55.7±9.2??ka, based on a terrestrial cosmogenic 10Be depth profile and 36Cl analyses on basalt boulders, respectively. The displacement and age constraints for the fan yield a slip rate of 1.8 +0.8/-0.8 mm/yr to 2.4 +1.2/-1.1 mm/yr (2?) along the northern Warm Springs Valley fault system for the past 41.4–55.7 ka. In contrast to this longer?term slip rate, shorelines associated with the Sehoo highstand of Lake Lahontan (~15.8??ka) adjacent to the Fort Sage fan are dextrally faulted at most 3 m, which limits a maximum post?15.8 ka slip rate to 0.2??mm/yr. These relations indicate that the post?Lahontan slip rate on the fault is only about one?tenth the longer?term (41–56 ka) average slip rate. This apparent slip?rate variation may be related to co?dependent interaction with the nearby Honey Lake fault system, which shows evidence of an accelerated period of mid?Holocene earthquakes.

Gold, Ryan; dePolo, Craig; Briggs, Richard W.; Crone, Anthony

2013-01-01

381

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

NASA Astrophysics Data System (ADS)

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.

Williams, A. Park; Funk, Chris

2011-12-01

382

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

PubMed Central

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

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

383

A province-scale block model of Walker Lane and western Basin and Range crustal deformation constrained by GPS observations (Invited)  

NASA Astrophysics Data System (ADS)

The Walker Lane in the western Great Basin of the western United States is an 800 km long and 100 km wide zone of active intracontinental transtension that absorbs ~10 mm/yr, about 20% of the Pacific/North America plate boundary relative motion. Lying west of the Sierra Nevada/Great Valley microplate (SNGV) and adjoining the Basin and Range Province to the east, deformation is predominantly shear strain overprinted with a minor component of extension. The Walker Lane responds with faulting, block rotations, structural step-overs, and has distinct and varying partitioned domains of shear and extension. Resolving these complex deformation patterns requires a long term observation strategy with a dense network of GPS stations (spacing ~20 km). The University of Nevada, Reno operates the 373 station Mobile Array of GPS for Nevada transtension (MAGNET) semi-continuous network that supplements coverage by other networks such as EarthScope's Plate Boundary Observatory, which alone has insufficient density to resolve the deformation patterns. Uniform processing of data from these GPS mega-networks provides a synoptic view and new insights into the kinematics and mechanics of Walker Lane tectonics. We present velocities for thousands of stations with time series between 3 to 17 years in duration aligned to our new GPS-based North America fixed reference frame NA12. The velocity field shows a rate budget across the southern Walker Lane of ~10 mm/yr, decreasing northward to ~7 mm/yr at the latitude of the Mohawk Valley and Pyramid Lake. We model the data with a new block model that estimates rotations and slip rates of known active faults between the Mojave Desert and northern Nevada and northeast California. The density of active faults in the region requires including a relatively large number of blocks in the model to accurately estimate deformation patterns. With 49 blocks, our the model captures structural detail not represented in previous province-scale models, and improves our ability to compare results to geologic fault slip rates. Modeling the kinematics on this scale has the advantages of 1) reducing the impact of poorly constrained boundaries on small geographically limited models, 2) consistent modeling of rotations across major structural step-overs near the Mina deflection and Carson domain, 3) tracking the kinematics of the south-to-north varying budget of Walker Lane deformation by solving for extension in the Basin and Range to the east, and 4) using a contiguous SNGV as a uniform western kinematic boundary condition. We compare contemporary deformation to geologic slip rates and longer term rotation rates estimated from rock paleomagnetism. GPS-derived block rotation rates are somewhat dependent on model regularization, but are generally within 1° per million years, and tend to be slower than published paleomagnetic rotations rates. GPS data, together with neotectonic and rock paleomagnetism studies provide evidence that the relative importance of Walker Lane block rotations and fault slip continues to evolve, giving way to a more through-going system with slower rotation rates and higher slip rates on individual faults.

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

2013-12-01

384

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

PubMed Central

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

Williams, Paul T.; Thompson, Paul D.

2013-01-01

385

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)

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.

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

2008-12-01

386

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

SciTech Connect

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.

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

2012-01-01

387

Interview with John Walker  

E-print Network

of the class in competition with two girls and remained there throughout the junior school period; became head boy there; also developing into a keen sportsman, playing soccer and cricket; had a very happy childhood with supportive and loving extended family... Florey and Chain worked together in the Sir William Dunn School of Pathology discussing a research programme on chemical compounds that might kill bacteria, one of which was lysozyme because Fleming had actually described making little boys weep...

Walker, John E

2008-08-13

388

1 Mark E. Walker  

E-print Network

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

Walker, Mark

389

Linkage to chromosome 2q36.1 in autosomal dominant Dandy-Walker malformation with occipital cephalocele and evidence for genetic heterogeneity  

PubMed Central

We previously reported a Vietnamese-American family with isolated autosomal dominant occipital cephalocele. Upon further neuroimaging studies, we have recharacterized this condition as autosomal dominant Dandy-Walker with occipital cephalocele (ADDWOC). A similar ADDWOC family from Brazil was also recently described. To determine the genetic etiology of ADDWOC, we performed genome-wide linkage analysis on members of the Vietnamese-American and Brazilian pedigrees. Linkage analysis of the Vietnamese-American family identified the ADDWOC causative locus on chromosome 2q36.1 with a multipoint parametric LOD score of 3.3, while haplotype analysis refined the locus to 1.1 Mb. Sequencing of the five known genes in this locus did not identify any protein-altering mutations. However, a terminal deletion of chromosome 2 in a patient with an isolated case of Dandy-Walker malformation also encompassed the 2q36.1 chromosomal region. The Brazilian pedigree did not show linkage to this 2q36.1 region. Taken together, these results demonstrate a locus for ADDWOC on 2q36.1 and also suggest locus heterogeneity for ADDWOC. PMID:18204864

Jalali, Ali; Aldinger, Kimberly A.; Chary, Ajit; Mclone, David G.; Bowman, Robin M.; Le, Luan Cong; Jardine, Phillip; Newbury-Ecob, Ruth; Mallick, Andrew; Jafari, Nadereh; Russell, Eric J.; Curran, John; Nguyen, Pam; Ouahchi, Karim; Lee, Charles; Dobyns, William B.; Millen, Kathleen J.; Pina-Neto, Joao M.; Kessler, John A.; Bassuk, Alexander G.

2010-01-01

390

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

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.

Savage, James C.; Simpson, Robert W.

2013-01-01

391

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

392

Mach's principle: Exact frame-dragging via gravitomagnetism in perturbed Friedmann-Robertson-Walker universes with K=({+-}1,0)  

SciTech Connect

We show that there is exact dragging of the axis directions of local inertial frames by a weighted average of the cosmological energy currents via gravitomagnetism for all linear perturbations of all Friedmann-Robertson-Walker (FRW) universes and of Einstein's static closed universe, and for all energy-momentum-stress tensors and in the presence of a cosmological constant. This includes FRW universes arbitrarily close to the Milne Universe and the de Sitter universe. Hence the postulate formulated by Ernst Mach about the physical cause for the time-evolution of inertial axes is shown to hold in general relativity for linear perturbations of FRW universes. - The time-evolution of local inertial axes (relative to given local fiducial axes) is given experimentally by the precession angular velocity {omega}-vector{sub gyro} of local gyroscopes, which in turn gives the operational definition of the gravitomagnetic field: B-vector{sub g}{identical_to}-2{omega}-vector{sub gyro}. The gravitomagnetic field is caused by energy currents J-vector{sub {epsilon}} via the momentum constraint, Einstein's G{sup 0-}circumflex{sub i-circumflex} equation, (-{delta}+{mu}{sup 2})A-vector{sub g}=-16{pi}G{sub N}J-vector{sub {epsilon}} with B-vector{sub g}=curl A-vector{sub g}. This equation is analogous to Ampere's law, but it holds for all time-dependent situations. {delta} is the de Rham-Hodge Laplacian, and {delta}=-curl curl for the vorticity sector in Riemannian 3-space. - In the solution for an open universe the 1/r{sup 2}-force of Ampere is replaced by a Yukawa force Y{sub {mu}}(r)=(-d/dr)[(1/R)exp(-{mu}r)], form-identical for FRW backgrounds with K=(-1,0). Here r is the measured geodesic distance from the gyroscope to the cosmological source, and 2{pi}R is the measured circumference of the sphere centered at the gyroscope and going through the source point. The scale of the exponential cutoff is the H-dot radius, where H is the Hubble rate, dot is the derivative with respect to cosmic time, and {mu}{sup 2}=-4(dH/dt). Analogous results hold in closed FRW universes and in Einstein's closed static universe.--We list six fundamental tests for the principle formulated by Mach: all of them are explicitly fulfilled by our solutions.--We show that only energy currents in the toroidal vorticity sector with l=1 can affect the precession of gyroscopes. We show that the harmonic decomposition of toroidal vorticity fields in terms of vector spherical harmonics X-vector{sub lm}{sup -} has radial functions which are form-identical for the 3-sphere, the hyperbolic 3-space, and Euclidean 3-space, and are form-identical with the spherical Bessel-, Neumann-, and Hankel functions. - The Appendix gives the de Rham-Hodge Laplacian on vorticity fields in Riemannian 3-spaces by equations connecting the calculus of differential forms with the curl notation. We also give the derivation the Weitzenboeck formula for the difference between the de Rham-Hodge Laplacian {delta} and the ''rough'' Laplacian {nabla}{sup 2} on vector fields.

Schmid, Christoph [ETH Zurich, Institute for Theoretical Physics, 8093 Zurich (Switzerland)

2009-03-15

393

Mach's principle: Exact frame-dragging via gravitomagnetism in perturbed Friedmann-Robertson-Walker universes with K=(±1,0)  

NASA Astrophysics Data System (ADS)

We show that there is exact dragging of the axis directions of local inertial frames by a weighted average of the cosmological energy currents via gravitomagnetism for all linear perturbations of all Friedmann-Robertson-Walker (FRW) universes and of Einstein’s static closed universe, and for all energy-momentum-stress tensors and in the presence of a cosmological constant. This includes FRW universes arbitrarily close to the Milne Universe and the de Sitter universe. Hence the postulate formulated by Ernst Mach about the physical cause for the time-evolution of inertial axes is shown to hold in general relativity for linear perturbations of FRW universes.—The time-evolution of local inertial axes (relative to given local fiducial axes) is given experimentally by the precession angular velocity ??gyro of local gyroscopes, which in turn gives the operational definition of the gravitomagnetic field: B?g?-2??gyro. The gravitomagnetic field is caused by energy currents J?? via the momentum constraint, Einstein’s G0^i^ equation, (-?+?2)A?g=-16?GNJ?? with B?g=curlA?g. This equation is analogous to Ampère’s law, but it holds for all time-dependent situations. ? is the de Rham-Hodge Laplacian, and ?=-curlcurl for the vorticity sector in Riemannian 3-space.—In the solution for an open universe the 1/r2-force of Ampère is replaced by a Yukawa force Y?(r)=(-d/dr)[(1/R)exp?(-?r)], form-identical for FRW backgrounds with K=(-1,0). Here r is the measured geodesic distance from the gyroscope to the cosmological source, and 2?R is the measured circumference of the sphere centered at the gyroscope and going through the source point. The scale of the exponential cutoff is the H-dot radius, where H is the Hubble rate, dot is the derivative with respect to cosmic time, and ?2=-4(dH/dt). Analogous results hold in closed FRW universes and in Einstein’s closed static universe.—We list six fundamental tests for the principle formulated by Mach: all of them are explicitly fulfilled by our solutions.—We show that only energy currents in the toroidal vorticity sector with ?=1 can affect the precession of gyroscopes. We show that the harmonic decomposition of toroidal vorticity fields in terms of vector spherical harmonics X??m- has radial functions which are form-identical for the 3-sphere, the hyperbolic 3-space, and Euclidean 3-space, and are form-identical with the spherical Bessel-, Neumann-, and Hankel functions.—The Appendix gives the de Rham-Hodge Laplacian on vorticity fields in Riemannian 3-spaces by equations connecting the calculus of differential forms with the curl notation. We also give the derivation the Weitzenböck formula for the difference between the de Rham-Hodge Laplacian ? and the “rough” Laplacian ?2 on vector fields.

Schmid, Christoph

2009-03-01

394

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

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

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

2014-01-01

395

Assessment of Prey Preference by the Generalist Predator, Mallada basalis (Walker), When Offered Two Species of Spider Mites, Tetranychus kanzawai Kishida and Panonychus citri (McGregor) on Papaya  

Technology Transfer Automated Retrieval System (TEKTRAN)

We investigated potential prey preference of the generalist predator Mallada basalis (Walker) when offered two mites, Tetranychus kanzawai Kishida and Panonychus citri (McGregor), both important pests on papaya. Laboratory choice tests revealed that none of the three larval instars of M. basalis sho...

396

FGF17, a gene involved in cerebellar development, is downregulated in a patient with Dandy-Walker malformation carrying a de novo 8p deletion.  

PubMed

Fibroblast growth factors (FGFs) are important signaling molecules which act during early vertebrate central nervous system development. FGF17, together with FGF8, is a key factor in the patterning of the mid-hindbrain region with a complex picture of spatiotemporal gene expression during the various stages of cerebellar development. Disruption or reduced expression of fgf17 in mice has been associated with cerebellar vermis abnormalities. We have identified a de novo 2.3-Mb deletion of chromosome 8p21.2-p21.3 in a girl with severe growth retardation, seizures, and classical Dandy-Walker malformation. Analysis of gene expression in blood lymphocytes and skin fibroblasts revealed markedly reduced levels of FGF17, which is located 1 Mb from the proximal deletion breakpoint. This is the first report of a human cerebellar malformation associated with transcriptional downregulation of the FGF17 gene. PMID:21484435

Zanni, Ginevra; Barresi, Sabina; Travaglini, Lorena; Bernardini, Laura; Rizza, Teresa; Digilio, Maria Cristina; Mercuri, Eugenio; Cianfarani, Stefano; Valeriani, Massimiliano; Ferraris, Alessandro; Da Sacco, Letizia; Novelli, Antonio; Valente, Enza Maria; Dallapiccola, Bruno; Bertini, Enrico Silvio

2011-08-01

397

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

PubMed Central

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

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

2014-01-01

398

Natural-product-based insecticidal agents 14. Semisynthesis and insecticidal activity of new piperine-based hydrazone derivatives against Mythimna separata Walker in vivo.  

PubMed

In continuation of our program aimed at the discovery and development of natural-product-based insecticidal agents, twenty-six new piperine-based hydrazone derivatives were synthesized from piperine, an alkaloid isolated from Piper nigrum Linn. The single-crystal structures of 6c, 6q and 6w were unambiguously confirmed by X-ray crystallography. Their insecticidal activity was evaluated against the pre-third-instar larvae of Mythimna separata Walker in vivo. Especially compounds 6b, 6i and 6r, the final mortality rates of which, at the concentration of 1 mg/mL, were 62.1%, 65.5% and 65.5%, respectively, exhibited more pronounced insecticidal activity compared to toosendanin at 1 mg/mL, a commercial botanical insecticide isolated from Melia azedarach. It suggested that introduction of the substituents at the C-2 position on the phenyl ring of the hydrazone derivatives was important for their insecticidal activity. PMID:24018189

Qu, Huan; Yu, Xiang; Zhi, Xiaoyan; Lv, Min; Xu, Hui

2013-10-15

399

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

PubMed Central

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

2013-01-01

400

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

SciTech Connect

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 spectrum hunting/gathering and horticulture are represented. Site structures includes food preparation areas associated with storage/drying facilities, hearths, and trash pits. Settlements appear to be semi-permanent, and involved in diverse procurement activities spanning two or more seasons. Level 2 habitation is radiocarbon dated between A.D. 1116 to 1255, which indicates contemporary development with Central Plains Tradition complexes, as well as Loseke Creek/Missouri Bluffs Woodland groups. Level 5 evidences settlement change as probable interaction with Central Plains Tradition complexes.

Haas, D.R.

1983-12-01

401

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

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

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

2011-12-01

402

Style of deformation along the Death Valley-Furnace Creek fault zone and other faults in the southern Walker Lane, Nevada and California  

SciTech Connect

Quaternary normal and right-lateral faults and associated lineaments in the southern part of the Walker Lane are anomalous with respect to the north-striking normal faults in most of the central Great Basin. The authors identify and characterize many faults and lineaments that were previously unmapped, with the exception of faults in the Death Valley-Furnace Creek fault zone (DVFCFZ) and some faults in and near the Nevada Test Site. Faults and associated lineaments in deposits of late Cenozoic age are distinguished on the basis of age of most recent activity and orientation, and are grouped into two domains. One domain is characterized by northwest-striking faults and lineaments and associated north-striking en echelon structures within the DVFCFZ and the Pahrump fault zone; the other domain is characterized by north- to northeast-striking faults and linearments within a broad region east of the DVFCFZ that narrows southward toward the Pahrump fault zone. Preliminary observations of faults and linearments suggest dominantly right-oblique slip in the first domain and dominantly dip-slip in the second domain. The DVFCFZ is a regional right-lateral strike-slip system that shows changes in style of deformation along strike. Numerous normal faults at the northern end of the DVFCFZ in northern fish Lake Valley and the Volcanic Hills form an extensional right step that links the DVFCFZ with northwest-striking right-lateral faults of the northern part of the Walker Lane. South of this extensional step, the DVFCFZ trends southeast along strike-slip faults from central Fish Lake Valley to the latitude of Furnace Creek. From Furnace Creek, the fault zone apparently steps left to the Pahrump fault zone in the area of Ash Meadows where a complex zone of folds and faults of diverse orientation suggest local compression. This stepover coincides with east-northeast-striking faults that appear to be an extension of the left-lateral Rock Valley fault zone.

Noller, J.S. (William Lettis and Associates, Inc., Oakland, CA (United States)); Reheis, M.C. (Geological Survey, Denver, CO (United States))

1993-04-01

403

Radiographic and functional results in the treatment of early stages of Charcot neuroarthropathy with a walker boot and immediate weight bearing  

PubMed Central

Background One of the most common gold standards for the treatment of Charcot neuroarthropathy (CN) in the early Eichenholtz stages I and II is immobilization with the total contact casting and lower limb offloading. However, the total amount of offloading is still debatable. Objectives This study evaluates the clinical and radiographic findings in the treatment of early stages of CN (Eichenholtz stages I and II) with a walker boot and immediate total weight-bearing status. Methods Twenty-two patients with type 2 diabetes mellitus (DM) and CN of Eichenholtz stages I and II were selected for non-operative treatment. All patients were educated about their condition, and full weight bearing was allowed as tolerated. Patients were monitored on a fortnightly basis in the earlier stages, with clinical examination, temperature measurement, and standardized weight-bearing radiographs. Their American Orthopedic Foot and Ankle Society (AOFAS) scores were determined before and after the treatment protocol. Results No cutaneous ulcerations or infections were observed in the evaluated cases. The mean measured angles at the beginning and end of the study, although showing relative increase, did not present a statistically significant difference (p > 0.05). Mean AOFAS scores showed a statistically significant improvement by the end of the study (p < 0.005). Conclusion The treatment of early stages of CN (Eichenholtz stages I and II) with emphasis on walker boot and immediate weight bearing has shown a good functional outcome, non-progressive deformity on radiographic assessment, and promising results as a safe treatment option. PMID:24179634

Parisi, Maria Candida Ribeiro; Godoy-Santos, Alexandre Leme; Ortiz, Rafael Trevisan; Sposeto, Rafael Barban; Sakaki, Marcos Hideyo; Nery, Marcia; Fernandes, Tulio Diniz

2013-01-01

404

Surface faulting and paleoseismic history of the 1932 Cedar Mountain earthquake area, west-central Nevada, and implications for modern tectonics of the Walker Lane  

USGS Publications Warehouse

The 1932 Cedar Mountain earthquake (Ms 7.2) was one of the largest historical events in the Walker Lane region of western Nevada, and it produced a complicated strike-slip rupture pattern on multiple Quaternary faults distributed through three valleys. Primary, right-lateral surface ruptures occurred on north-striking faults in Monte Cristo Valley; small-scale lateral and normal offsets occurred in Stewart Valley; and secondary, normal faulting occurred on north-northeast-striking faults in the Gabbs Valley epicentral region. A reexamination of the surface ruptures provides new displacement and fault-zone data: maximum cumulative offset is estimated to be 2.7 m, and newly recognized faults extend the maximum width and end-to-end length of the rupture zone to 17 and 75 km, respectively. A detailed Quaternary allostratigraphic chronology based on regional alluvialgeomorphic relationships, tephrochronology, and radiocarbon dating provides a framework for interpreting the paleoseismic history of the fault zone. A late Wisconsinan alluvial-fan and piedmont unit containing a 32-36 ka tephra layer is a key stratigraphic datum for paleoseismic measurements. Exploratory trenching and radiocarbon dating of tectonic stratigraphy provide the first estimates for timing of late Quaternary faulting along the Cedar Mountain fault zone. Three trenches display evidence for six faulting events, including that in 1932, during the past 32-36 ka. Radiocarbon dating of organic soils interstratified with tectonically ponded silts establishes best-fit ages of the pre-1932 events at 4, 5,12,15, and 18 ka, each with ??2 ka uncertainties. On the basis of an estimated cumulative net slip of 6-12 m for the six faulting events, minimum and maximum late Quaternary slip rates are 0.2 and 0.7 mm/yr, respectively, and the preferred rate is 0.4-0.5 mm/yr. The average recurrence (interseismic) interval is 3600 yr. The relatively uniform thickness of the ponded deposits suggests that similar-size, characteristic rupture events may characterize late Quaternary slip on the zone. A comparison of event timing with the average late Quaternary recurrence interval indicates that slip has been largely regular (periodic) rather than temporally clustered. To account for the spatial separation of the primary surface faulting in Monte Cristo Valley from the epicenter and for a factor-of-two-to-three disparity between the instrumentally and geologically determined seismic moments associated with the earthquake, we hypothesize two alternative tectonic models containing undetected subevents. Either model would adequately account for the observed faulting on the basis of wrench-fault kinematics that may be associated with the Walker Lane. The 1932 Cedar Mountain earthquake is considered an important modern analogue for seismotectonic modeling and estimating seismic hazard in the Walker Lane region. In contrast to most other historical events in the Basin and Range province, the 1932 event did not occur along a major range-bounding fault, and no single, throughgoing basement structure can account for the observed rupture pattern. The 1932 faulting supports the concept that major earthquakes in the Basin and Range province can exhibit complicated distributive rupture patterns and that slip rate may not be a reliable criterion for modeling seismic hazard.

Bell, J.W.; DePolo, C.M.; Ramelli, A.R.; Sarna-Wojcicki, A. M.; Meyer, C.E.

1999-01-01

405

The importance of in-stream uptake for regulating stream concentrations and outputs of N and P from a forested watershed: evidence from long-term chemistry records for Walker Branch Watershed  

Microsoft Academic Search

Long-term, weekly measurements of streamwater nitrogen and phosphorus concentrations in the West Fork of Walker Branch, a 1st order forested stream in eastern Tennessee, were used to assess the importance of in-stream processes for controlling stream concentrations and watershed exports. Over the period from 1991 to 2002, there was a slight declining trend in watershed export of dissolved inorganic N

Patrick J. Mulholland

2004-01-01

406

Inferior Cerebellar Hypoplasia Resembling a Dandy-Walker-Like Malformation in Purebred Eurasier Dogs with Familial Non-Progressive Ataxia: A Retrospective and Prospective Clinical Cohort Study  

PubMed Central

Cerebellar malformations can be inherited or caused by insults during cerebellar development. To date, only sporadic cases of cerebellar malformations have been reported in dogs, and the genetic background has remained obscure. Therefore, this study`s objective was to describe the clinical characteristics, imaging features and pedigree data of a familial cerebellar hypoplasia in purebred Eurasier dogs. A uniform cerebellar malformation characterized by consistent absence of the caudal portions of the cerebellar vermis and, to a lesser degree, the caudal portions of the cerebellar hemispheres in association with large retrocerebellar fluid accumulations was recognized in 14 closely related Eurasier dogs. Hydrocephalus was an additional feature in some dogs. All dogs displayed non-progressive ataxia, which had already been noted when the dogs were 5 – 6 weeks old. The severity of the ataxia varied between dogs, from mild truncal sway, subtle dysmetric gait, dysequilibrium and pelvic limb ataxia to severe cerebellar ataxia in puppies and episodic falling or rolling. Follow-up examinations in adult dogs showed improvement of the cerebellar ataxia and a still absent menace response. Epileptic seizures occurred in some dogs. The association of partial vermis agenesis with an enlarged fourth ventricle and an enlarged caudal (posterior) fossa resembled a Dandy-Walker-like malformation in some dogs. Pedigree analyses were consistent with autosomal recessive inheritance. PMID:25668516

Bernardino, Filipa; Rentmeister, Kai; Schmidt, Martin J.; Bruehschwein, Andreas; Matiasek, Kaspar; Matiasek, Lara A.; Lauda, Alexander; Schoon, Heinz A.; Fischer, Andrea

2015-01-01

407

FOXC1 is required for normal cerebellar development and is a major contributor to chromosome 6p25.3 Dandy-Walker malformation  

PubMed Central

Dandy-Walker malformation (DWM), the most common human cerebellar malformation, has only one characterized associated locus1,2. Here we characterize a second DWM-linked locus on 6p25.3, showing that deletions or duplications encompassing FOXC1 are associated with cerebellar and posterior fossa malformations including cerebellar vermis hypoplasia (CVH), mega-cisterna magna (MCM) and DWM. Foxc1-null mice have embryonic abnormalities of the rhombic lip due to loss of mesenchyme-secreted signaling molecules with subsequent loss of Atoh1 expression in vermis. Foxc1 homozygous hypomorphs have CVH with medial fusion and foliation defects. Human FOXC1 heterozygous mutations are known to affect eye development, causing a spectrum of glaucoma-associated anomalies (Axenfeld-Rieger syndrome, ARS; MIM no. 601631). We report the first brain imaging data from humans with FOXC1 mutations and show that these individuals also have CVH. We conclude that alteration of FOXC1 function alone causes CVH and contributes to MCM and DWM. Our results highlight a previously unrecognized role for mesenchyme-neuroepithelium interactions in the mid-hindbrain during early embryogenesis. PMID:19668217

Aldinger, Kimberly A; Lehmann, Ordan J; Hudgins, Louanne; Chizhikov, Victor V; Bassuk, Alexander G; Ades, Lesley C; Krantz, Ian D; Dobyns, William B; Millen, Kathleen J

2010-01-01

408

COL4A1 Mutations Cause Ocular Dysgenesis, Neuronal Localization Defects, and Myopathy in Mice and Walker-Warburg Syndrome in Humans  

PubMed Central

Muscle-eye-brain disease (MEB) and Walker Warburg Syndrome (WWS) belong to a spectrum of autosomal recessive diseases characterized by ocular dysgenesis, neuronal migration defects, and congenital muscular dystrophy. Until now, the pathophysiology of MEB/WWS has been attributed to alteration in dystroglycan post-translational modification. Here, we provide evidence that mutations in a gene coding for a major basement membrane protein, collagen IV alpha 1 (COL4A1), are a novel cause of MEB/WWS. Using a combination of histological, molecular, and biochemical approaches, we show that heterozygous Col4a1 mutant mice have ocular dysgenesis, neuronal localization defects, and myopathy characteristic of MEB/WWS. Importantly, we identified putative heterozygous mutations in COL4A1 in two MEB/WWS patients. Both mutations occur within conserved amino acids of the triple-helix-forming domain of the protein, and at least one mutation interferes with secretion of the mutant proteins, resulting instead in intracellular accumulation. Expression and posttranslational modification of dystroglycan is unaltered in Col4a1 mutant mice indicating that COL4A1 mutations represent a distinct pathogenic mechanism underlying MEB/WWS. These findings implicate a novel gene and a novel mechanism in the etiology of MEB/WWS and expand the clinical spectrum of COL4A1-associated disorders. PMID:21625620

Harrington, Emily P.; de Leau, Michelle; Lyons, David; Kabaeva, Zhyldyz; Manzini, M. Chiara; Dobyns, William B.; Walsh, Christopher A.; Michele, Daniel E.; Gould, Douglas B.

2011-01-01

409

COL4A1 mutations cause ocular dysgenesis, neuronal localization defects, and myopathy in mice and Walker-Warburg syndrome in humans.  

PubMed

Muscle-eye-brain disease (MEB) and Walker Warburg Syndrome (WWS) belong to a spectrum of autosomal recessive diseases characterized by ocular dysgenesis, neuronal migration defects, and congenital muscular dystrophy. Until now, the pathophysiology of MEB/WWS has been attributed to alteration in dystroglycan post-translational modification. Here, we provide evidence that mutations in a gene coding for a major basement membrane protein, collagen IV alpha 1 (COL4A1), are a novel cause of MEB/WWS. Using a combination of histological, molecular, and biochemical approaches, we show that heterozygous Col4a1 mutant mice have ocular dysgenesis, neuronal localization defects, and myopathy characteristic of MEB/WWS. Importantly, we identified putative heterozygous mutations in COL4A1 in two MEB/WWS patients. Both mutations occur within conserved amino acids of the triple-helix-forming domain of the protein, and at least one mutation interferes with secretion of the mutant proteins, resulting instead in intracellular accumulation. Expression and posttranslational modification of dystroglycan is unaltered in Col4a1 mutant mice indicating that COL4A1 mutations represent a distinct pathogenic mechanism underlying MEB/WWS. These findings implicate a novel gene and a novel mechanism in the etiology of MEB/WWS and expand the clinical spectrum of COL4A1-associated disorders. PMID:21625620

Labelle-Dumais, Cassandre; Dilworth, David J; Harrington, Emily P; de Leau, Michelle; Lyons, David; Kabaeva, Zhyldyz; Manzini, M Chiara; Dobyns, William B; Walsh, Christopher A; Michele, Daniel E; Gould, Douglas B

2011-05-01

410

Efficacy of five volatile oils and their mixtures against the soft scale insect, Saissetia coffeae (Walker) (Hemiptera: Coccidae) infesting the Sago palm, Cycas revoluta in Alexandria, Egypt.  

PubMed

Five tested plant volatile oils and their mixtures were evaluated for controlling the coccid, Saissetia coffeae (Walker) on growing Sago palms Cycas revoluta in Antoniades public gardens, Alexandria, Egypt. The tested volatile oils at concentration rates of 0.5, 1 and 1.5% (v/v) were: Camphor 20%, Dill 20%, Rose 30%, Peppermint 20% and Clove 30% (v/v). Their mixtures were : Camphor/Peppermint, Camphor/Rose at a rate of 1:1, Camphor/Rose/Peppermint at 1:1:2 rate and Camphor/Rose/Dill at 2:1:1 rate. The results, as a general mean of residual reduction percent for the whole inspection intervals of the test lasted 2 days up to 9 days post treatment, indicated that the superior volatile oils in reducing the insect were both Camphor and Rose, followed by Dill, Peppermint and the least efficient one was the Clove oil. The evaluated mixtures of the volatile oils showed that each of Camphor/Rose/Peppermint, Camphor/Rose and Camphor/Peppermint mixtures attained a higher rank of efficiency against that of the assigned soft scale insect. PMID:21539257

Mesbah, H A; Nagda, A El Sayed; Mourad, A K; Abdel-Razak, I Soad; Samar, E Abd El-Rahman

2010-01-01

411

The essential role of the Walker A motifs of SUR1 in K-ATP channel activation by Mg-ADP and diazoxide.  

PubMed Central

The ATP-sensitive K-channel (K-ATP channel) plays a key role in insulin secretion from pancreatic beta-cells. It is closed by glucose metabolism, which stimulates insulin secretion, and opened by the drug diazoxide, which inhibits insulin release. Metabolic regulation is mediated by changes in ATP and Mg-ADP, which inhibit and potentiate channel activity, respectively. The beta-cell K-ATP channel consists of a pore-forming subunit, Kir6.2, and a regulatory subunit, SUR1. We have mutated (independently or together) two lysine residues in the Walker A (W(A)) motifs of the first (K719A) and second (K1384M) nucleotide-binding domains (NBDs) of SUR1. These mutations are expected to inhibit nucleotide hydrolysis. Our results indicate that the W(A) lysine of NBD1 (but not NBD2) is essential for activation of K-ATP currents by diazoxide. The potentiatory effects of Mg-ADP required the presence of the W(A) lysines in both NBDs. Mutant currents were slightly more sensitive to ATP than wild-type currents. Metabolic inhibition led to activation of wild-type and K1384M currents, but not K719A or K719A/K1384M currents, suggesting that there may be a factor in addition to ATP and ADP which regulates K-ATP channel activity. PMID:9135131

Gribble, F M; Tucker, S J; Ashcroft, F M

1997-01-01

412

Comparison of body segmental kinematic characteristics between children with cerebral palsy performing sit-to-stand with and without a walker.  

PubMed

The study investigated how the subjects, 18 children with spastic diplegia aged 7-14 years, attained sit-to-stand (STS). The children were divided into two groups and three STS conditions: 1) those who could attain STS independently (I-STS), 2) those who could not attain STS independently (D-STS), and 3) subjects from the D-STS condition who could successfully attain STS with the walker (W-STS). The results showed that I-STS had more mean maximum horizontal location of the upper body and knee than the hip. All body segments of D-STS followed the same model as the I-STS condition, but they moved with less magnitude than I-STS. W-STS presented both pattern and magnitudes relatively similar to I-STS. Furthermore, I-STS showed the highest mean maximum horizontal and vertical velocities of body segments, when compared with the other STS conditions. W-STS performed the mean maximum horizontal and vertical linear velocities of all selected segments close to D-STS did. PMID:23363018

Thanapan, Puthamaluk; Prasertsukdee, Saipin; Vachalathiti, Roongtiwa

2013-03-01

413

Populational parameters of Spalangia endius Walker (Hymenoptera: Pteromalidae) on Pupae of Musca domestica L. (Diptera: Muscidae) treated with two strains of Beauveria bassiana (Bals.) Vuil. (Deuteromycetes).  

PubMed

The parasitoid Spalangia endius Walker is an efficient controller of Dipteran pupae, such as Musca domestica L. The entomopathogenic fungus Beauveria bassiana (Bals.) Vuil. is a regulator of insect populations, including these synanthropic pests. The aim of this work was to explore the possibilities of utilizing both agents in a combined form for the biocontrol of the domestic fly. Recently formed M. domestica pupae were inoculated by immersion in conidia suspension (10(8) conidia/ml) with two strains of B. bassiana (Bb6 and Bb10). The inoculated pupae were offered to the female parasitoid. In one bioassay they were offered pupae inoculated a single day and in other, pupae inoculated the following day as well. In both bioassays non inoculated (control) pupae were offered to the parasitoids until their death. Thirty females of S. endius were used for each strain and bioassay. From the study of the parasitoid offspring, life tables were built and the reproduction net rate (R(0)) and intrinsic natural increase (r(m)) were obtained among other demographic parameters; the parasitism percentages and sex ratios were also analyzed. B. bassiana did not affect significantly the biodemography of the parasitoid when pupae were inoculated a single time. On the other hand the R0 and the rm were smaller than that of the control without the fungus when pupae were inoculated twice, although sporulation was not observed in the cadavers of S. endius. PMID:17934618

Lecuona, Roberto; Crespo, Diana; La Rossa, Francisco

2007-01-01

414

Ethnically Diverse Causes of Walker-Warburg Syndrome (WWS): FCMD Mutations Are a More Common Cause of WWS Outside of the Middle East  

PubMed Central

Walker-Warburg syndrome (WWS) is a genetically heterogeneous autosomal recessive disease characterized by congenital muscular dystrophy, cobblestone lissencephaly, and ocular malformations. Mutations in six genes involved in the glycosylation of ?-dystroglycan (POMT1, POMT2, POMGNT1, FCMD, FKRP and LARGE) have been identified in WWS patients, but account for only a portion of WWS cases. To better understand the genetics of WWS and establish the frequency and distribution of mutations across WWS genes, we genotyped all known loci in a cohort of 43 WWS patients of varying geographical and ethnic origin. Surprisingly, we reached a molecular diagnosis for 40% of our patients and found mutations in POMT1, POMT2, FCMD and FKRP, many of which were novel alleles, but no mutations in POMGNT1 or LARGE. Notably, the FCMD gene was a more common cause of WWS than previously expected in the European/American subset of our cohort, including all Ashkenazi Jewish cases, who carried the same founder mutation. PMID:18752264

Manzini, M. Chiara; Gleason, Danielle; Chang, Bernard S.; Hill, R. Sean; Barry, Brenda J.; Partlow, Jennifer N.; Poduri, Annapurna; Currier, Sophie; Galvin-Parton, Patricia; Shapiro, Lawrence R.; Schmidt, Karen; Davis, Jessica G.; Basel-Vanagaite, Lina; Seidahmed, Mohamed Z.; Salih, Mustafa A. M.; Dobyns, William B.; Walsh, Christopher A.

2008-01-01

415

Ethnically diverse causes of Walker-Warburg syndrome (WWS): FCMD mutations are a more common cause of WWS outside of the Middle East.  

PubMed

Walker-Warburg syndrome (WWS) is a genetically heterogeneous autosomal recessive disease characterized by congenital muscular dystrophy, cobblestone lissencephaly, and ocular malformations. Mutations in six genes involved in the glycosylation of á-dystroglycan (POMT1, POMT2, POMGNT1, FCMD, FKRP and LARGE) have been identified in WWS patients, but account for only a portion of WWS cases. To better understand the genetics of WWS and establish the frequency and distribution of mutations across WWS genes, we genotyped all known loci in a cohort of 43 WWS patients of varying geographical and ethnic origin. Surprisingly, we reached a molecular diagnosis for 40% of our patients and found mutations in POMT1, POMT2, FCMD and FKRP, many of which were novel alleles, but no mutations in POMGNT1 or LARGE. Notably, the FCMD gene was a more common cause of WWS than previously expected in the European/American subset of our cohort, including all Ashkenazi Jewish cases, who carried the same founder mutation. PMID:18752264

Manzini, M Chiara; Gleason, Danielle; Chang, Bernard S; Hill, R Sean; Barry, Brenda J; Partlow, Jennifer N; Poduri, Annapurna; Currier, Sophie; Galvin-Parton, Patricia; Shapiro, Lawrence R; Schmidt, Karen; Davis, Jessica G; Basel-Vanagaite, Lina; Seidahmed, Mohamed Z; Salih, Mustafa A M; Dobyns, William B; Walsh, Christopher A

2008-11-01

416

AP1S2 is mutated in X-linked Dandy-Walker malformation with intellectual disability, basal ganglia disease and seizures (Pettigrew syndrome).  

PubMed

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

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

417

Mutations in the O-Mannosyltransferase Gene POMT1 Give Rise to the Severe Neuronal Migration Disorder Walker-Warburg Syndrome  

PubMed Central

Walker-Warburg syndrome (WWS) is an autosomal recessive developmental disorder characterized by congenital muscular dystrophy and complex brain and eye abnormalities. A similar combination of symptoms is presented by two other human diseases, muscle-eye-brain disease (MEB) and Fukuyama congenital muscular dystrophy (FCMD). Although the genes underlying FCMD (Fukutin) and MEB (POMGnT1) have been cloned, loci for WWS have remained elusive. The protein products of POMGnT1 and Fukutin have both been implicated in protein glycosylation. To unravel the genetic basis of WWS, we first performed a genomewide linkage analysis in 10 consanguineous families with WWS. The results indicated the existence of at least three WWS loci. Subsequently, we adopted a candidate-gene approach in combination with homozygosity mapping in 15 consanguineous families with WWS. Candidate genes were selected on the basis of the role of the FCMD and MEB genes. Since POMGnT1 encodes an O-mannoside N-acetylglucosaminyltransferase, we analyzed the possible implication of O-mannosyl glycan synthesis in WWS. Analysis of the locus for O-mannosyltransferase 1 (POMT1) revealed homozygosity in 5 of 15 families. Sequencing of the POMT1 gene revealed mutations in 6 of the 30 unrelated patients with WWS. Of the five mutations identified, two are nonsense mutations, two are frameshift mutations, and one is a missense mutation. Immunohistochemical analysis of muscle from patients with POMT1 mutations corroborated the O-mannosylation defect, as judged by the absence of glycosylation of ?-dystroglycan. The implication of O-mannosylation in MEB and WWS suggests new lines of study in understanding the molecular basis of neuronal migration. PMID:12369018

Beltrán-Valero de Bernabé, Daniel; Currier, Sophie; Steinbrecher, Alice; Celli, Jacopo; van Beusekom, Ellen; van der Zwaag, Bert; Kayserili, Hülya; Merlini, Luciano; Chitayat, David; Dobyns, William B.; Cormand, Bru; Lehesjoki, Ana-Elina; Cruces, Jesús; Voit, Thomas; Walsh, Christopher A.; van Bokhoven, Hans; Brunner, Han G.

2002-01-01

418

AP1S2 is mutated in X-linked Dandy–Walker malformation with intellectual disability, basal ganglia disease and seizures (Pettigrew syndrome)  

PubMed Central

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

Cacciagli, Pierre; Desvignes, Jean-Pierre; Girard, Nadine; Delepine, Marc; Zelenika, Diana; Lathrop, Mark; Lévy, Nicolas; Ledbetter, David H; Dobyns, William B; Villard, Laurent

2014-01-01

419

Uncaria tomentosa exerts extensive anti-neoplastic effects against the Walker-256 tumour by modulating oxidative stress and not by alkaloid activity.  

PubMed

This study aimed to compare the anti-neoplastic effects of an Uncaria tomentosa (UT) brute hydroethanolic (BHE) extract with those of two fractions derived from it. These fractions are choroformic (CHCl3) and n-butanolic (BuOH), rich in pentacyclic oxindole alkaloids (POA) and antioxidant substances, respectively. The cancer model was the subcutaneous inoculation of Walker-256 tumour cells in the pelvic limb of male Wistar rat. Subsequently to the inoculation, gavage with BHE extract (50 mg.kg(-1)) or its fractions (as per the yield of the fractioning process) or vehicle (Control) was performed during 14 days. Baseline values, corresponding to individuals without tumour or treatment with UT, were also included. After treatment, tumour volume and mass, plasma biochemistry, oxidative stress in liver and tumour, TNF-? level in liver and tumour homogenates, and survival rates were analysed. Both the BHE extract and its BuOH fraction successfully reduced tumour weight and volume, and modulated anti-oxidant systems. The hepatic TNF-? level indicated a greater effect from the BHE extract as compared to its BuOH fraction. Importantly, both the BHE extract and its BuOH fraction increased the survival time of the tumour-bearing animals. Inversely, the CHCl3 fraction was ineffective. These data represent an in vivo demonstration of the importance of the modulation of oxidative stress as part of the anti-neoplastic activity of UT, as well as constitute evidence of the lack of activity of isolated POAs in the primary tumour of this tumour lineage. These effects are possibly resulting from a synergic combination of substances, most of them with antioxidant properties. PMID:23408945

Dreifuss, Arturo Alejandro; Bastos-Pereira, Amanda Leite; Fabossi, Isabella Aviles; Lívero, Francislaine Aparecida Dos Reis; Stolf, Aline Maria; Alves de Souza, Carlos Eduardo; Gomes, Liana de Oliveira; Constantin, Rodrigo Polimeni; Furman, Aline Emmer Ferreira; Strapasson, Regiane Lauriano Batista; Teixeira, Simone; Zampronio, Aleksander Roberto; Muscará, Marcelo Nicolás; Stefanello, Maria Elida Alves; Acco, Alexandra

2013-01-01

420

Uncaria tomentosa Exerts Extensive Anti-Neoplastic Effects against the Walker-256 Tumour by Modulating Oxidative Stress and Not by Alkaloid Activity  

PubMed Central

This study aimed to compare the anti-neoplastic effects of an Uncaria tomentosa (UT) brute hydroethanolic (BHE) extract with those of two fractions derived from it. These fractions are choroformic (CHCl3) and n-butanolic (BuOH), rich in pentacyclic oxindole alkaloids (POA) and antioxidant substances, respectively. The cancer model was the subcutaneous inoculation of Walker-256 tumour cells in the pelvic limb of male Wistar rat. Subsequently to the inoculation, gavage with BHE extract (50 mg.kg?1) or its fractions (as per the yield of the fractioning process) or vehicle (Control) was performed during 14 days. Baseline values, corresponding to individuals without tumour or treatment with UT, were also included. After treatment, tumour volume and mass, plasma biochemistry, oxidative stress in liver and tumour, TNF-? level in liver and tumour homogenates, and survival rates were analysed. Both the BHE extract and its BuOH fraction successfully reduced tumour weight and volume, and modulated anti-oxidant systems. The hepatic TNF-? level indicated a greater effect from the BHE extract as compared to its BuOH fraction. Importantly, both the BHE extract and its BuOH fraction increased the survival time of the tumour-bearing animals. Inversely, the CHCl3 fraction was ineffective. These data represent an in vivo demonstration of the importance of the modulation of oxidative stress as part of the anti-neoplastic activity of UT, as well as constitute evidence of the lack of activity of isolated POAs in the primary tumour of this tumour lineage. These effects are possibly resulting from a synergic combination of substances, most of them with antioxidant properties. PMID:23408945

Dreifuss, Arturo Alejandro; Bastos-Pereira, Amanda Leite; Fabossi, Isabella Aviles; Lívero, Francislaine Aparecida dos Reis; Stolf, Aline Maria; Alves de Souza, Carlos Eduardo; Gomes, Liana de Oliveira; Constantin, Rodrigo Polimeni; Furman, Aline Emmer Ferreira; Strapasson, Regiane Lauriano Batista; Teixeira, Simone; Zampronio, Aleksander Roberto; Muscará, Marcelo Nicolás; Stefanello, Maria Elida Alves; Acco, Alexandra

2013-01-01

421

Transcriptomics and Identification of the Chemoreceptor Superfamily of the Pupal Parasitoid of the Oriental Fruit Fly, Spalangia endius Walker (Hymenoptera: Pteromalidae)  

PubMed Central

Background The oriental fruit fly, Bactrocera dorsalis Hendel, causes serious losses to fruit production and is one of the most economically important pests in many countries, including China, Spalangia endius Walker is a pupal parasitoid of various dipteran hosts, and may be considered a potentially important ectoparasitic pupal parasitoid of B. dorsalis. However, lack of genetic information on this organism is an obstacle to understanding the mechanisms behind its interaction with this host. Analysis of the S. endius transcriptome is essential to extend the resources of genetic information on this species and, to support studies on S. endius on the host B. dorsalis. Methodology/Principal Findings We performed de novo assembly RNA-seq of S. endius. We obtained nearly 10 Gbp of data using a HiSeq platform, and 36319 high-quality transcripts using Trinity software. A total of 22443 (61.79%) unigenes were aligned to homologous sequences in the jewel wasp and honeybee (Apis florae) protein set from public databases. A total of 10037 protein domains were identified in 7892 S. endius transcripts using HMMER3 software. We identified expression of six gustatory receptor and 21 odorant receptor genes in the sample, with only one gene having a high expression level in each family. The other genes had a low expression level, including two genes regulated by splicing. This result may be due to the wasps being kept under laboratory conditions. Additionally, a total of 3727 SSR markers were predicted, which could facilitate the identification of polymorphisms and functional genes within wasp populations. Conclusion/Significance This transcriptome greatly improves our genetic understanding of S. endius and provides a large number of gene sequences for further study. PMID:24505315

Zhang, Yuping; Zheng, Yuan; Li, Dunsong; Fan, Yilin

2014-01-01

422

Evolution of Late Miocene to Contemporary Displacement Transfer Between the Northern Furnace Creek and Southern Fish Lake Valley Fault Zones and the Central Walker Lane, Western Great Basin, Nevada  

NASA Astrophysics Data System (ADS)

Late Miocene to contemporary displacement transfer from the north Furnace Creek (FCF) and southern Fish Lake Valley (FLVF) faults to structures in the central Walker Lane was and continues to be accommodated by a belt of WNW-striking left-oblique fault zones in the northern part of the southern Walker Lane. The WNW fault zones are 2-9 km wide belts of anastomosing fault strands that intersect the NNW-striking FCF and southern FLVF in northern Death Valley and southern Fish Lake Valley, respectively. The WNW fault zones extend east for over 60 km where they merge with a 5-10 km wide belt of N10W striking faults that marks the eastern boundary of the southern Walker Lane. Left-oblique displacement on WNW faults progressively decreases to the east, as motion is successively transferred northeast on NNE-striking faults. NNE faults localize and internally deform extensional basins that each record cumulative net vertical displacements of between 3.0 and 5.2 km. The transcurrent faults and associated basins decrease in age from south to north. In the south, the WNW Sylvania Mountain fault system initiated left-oblique motion after 7 Ma but does not have evidence of contemporary displacement. Farther north, the left-oblique motion on the Palmetto Mountain fault system initiated after 6.0 to 4.0 Ma and has well-developed scarps in Quaternary deposits. Cumulative left-lateral displacement for the Sylvania Mountain fault system is 10-15 km, and is 8-12 km for the Palmetto fault system. The NNE-striking faults that emanate from the left-oblique faults merge with NNW transcurrent faults farther north in the eastern part of the Mina deflection, which links the Owens Valley fault of eastern California to the central Walker Lane. Left-oblique displacement on the Sylvania Mountain and Palmetto Mountain fault zones deformed the Furnace Creek and Fish Lake Valley faults. Left-oblique motion on Sylvania Mountain fault deflected the FCF into the 15 km wide Cucomungo Canyon restraining bend, segmented the >3.0 km deep basin underlying southern Fish Lake Valley, and formed a 2 km wide restraining bend in the FLVF. Part of the left-oblique motion on the Palmetto Mountain fault zone crosses Fish Lake Valley and offsets the FLVF in a 3 km wide restraining bend with the remainder being taken-up by NNW structures along the eastern side of southern Fish Lake Valley.

Oldow, J. S.; Geissman, J. W.

2013-12-01

423

Disease Precautions for Dog Walkers  

MedlinePLUS

... have their pet evaluated by a veterinarian. Severe weather A dog’s tolerance to heat and cold varies ... seem to have a tougher time in hot weather and may require more frequent rests, shorter walks, ...

424

April 23, 2004 Mark Walker  

E-print Network

in arriving at a cohesive position on an array of complex issues. The treatment of Allocation, IOU benefits must not increase costs, or even have the potential for increased costs, associated with service, it makes some sense both legally and politically, to allocate the BPA system based on critical water

425

15 September 2006 Mark Walker  

E-print Network

that the Description of the Maturation Study within the project 198605000 White Sturgeon Mitigation and Restoration 2006 comments did not recommend that the Description of the Maturation Study within the project by which to determine sex and stage of maturity of white sturgeon which has been completed. The work

426

September 29, 2006 Mark Walker  

E-print Network

in the Wind River subbasin. Our current funding request for this project is $1,900,000 to meet a modified expression of genetic and life history diversity. This project is needed to fulfill the restoration and monitoring needs identified in the Wind River subbasin plan, the NOAA endorsed Lower Columbia salmon recovery

427

April 23, 2004 Mark Walker  

E-print Network

stake in the evolution of BPA's role. Please note that we are generally supportive of the joint comments the opportunity to comment on the Council's draft "Recommendations for the Future Role of the Bonneville Power Administration in Power Supply" dated April 9, 2004 (Draft). PNGC Power submits these comments on behalf

428

October 18, 2007 Mark Walker  

E-print Network

. Snake River Dams Analysis The PPC believes the Council made a proper decision when it omitted from of the Snake River Dams. In previous drafts it was suggested that the generation lost by removing the Snake that conservation and renewables could fill the void for generation lost by removing the Snake River Dams fails

429

October 5, 2006 Mark Walker  

E-print Network

of Fish and Wildlife (WDFW) with this project. While they pre-date the golden age of dinosaurs, two increase the number of turtles that survive to adulthood. Under optimal zoo conditions, the little turtles-native predators such as bullfrogs and threats to turtle habitat, the NWPCC cannot pull the rug out from under

430

October 3, 2006 Mark Walker  

E-print Network

the Councils F&W Program funding for Fiscal years 2007 ­ 2009. Emerald realizes the importance of preserving and protecting our natural resources including fish and wildlife. Simultaneously, we also realize the importance!!) to spend a significantly larger amount of money on additional projects, setting budgets above

431

October 6, 2006 Mark Walker  

E-print Network

. There is little time remaining to collect data before Condit Dam is removed or retrofitted for fish passage to dam removal, within a scientifically valid Before-After-Control-Impact (BACI) study design in preparation for salmon and steelhead reintroduction above Condit Dam, before major habitat restoration efforts

432

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

433

CONSTRUCTION AND ANALYSIS OF ANTENNAL cDNA LIBRARY FROM RICE STRIPED STEM BORER, Chilo suppressalis (WALKER) (LEPIDOPTERA: PYRALIDAE), AND EXPRESSION PROFILES OF PUTATIVE ODORANT-BINDING PROTEIN AND CHEMOSENSORY PROTEIN GENES.  

PubMed

In this study, we constructed a high-quality cDNA library from the antennae of the Chilo suppressalis (Walker) (Lepidoptera: Pyralidae). A total of 1,235 colonies with inserts greater than 0.7 kb were sequenced and analyzed. Homology searching coupled with bioinformatics analysis identified 15 and 7 cDNA sequences, respectively, encoding putative odorant-binding proteins (OBPs) and chemosensory proteins (CSPs). A phylogenetic tree of CsupCSPs showed that each CsupCSP has orthologs in Manduca sexta and Bombyx mori with strong bootstrapping support. One CSP was either very specific or more related to the CSPs of another species than to conspecific CSP. The expression profiles of the OBPs and CSPs in different tissues were measured by real-time quantitative PCR. The results revealed that of the 11 OBP genes, the transcript levels of CsupOBP1, CsupOBP5, and CsupOBP7 were higher in both male and female antennae than those in other tissues. And CsupCSP7 was highly expressed in both male and female antennae. Based on these results, the possible physiological functions of CsupOBPs and CsupCSPs were discussed. PMID:25639603

Gong, Zhong-Jun; Liu, Su; Jiang, Yan-Dong; Zhou, Wen-Wu; Liang, Qing-Mei; Cheng, Jiaan; Zhang, Chuan-Xi; Zhu, Zeng-Rong; Gurr, Geoff M

2015-05-01

434

April 21, 2004 Mr. Mark Walker  

E-print Network

development -- mainly geothermal, wind, and solar -- and participated in most of BPA's energy resource years, retiring at the end of 2002. For over 15 of those years, I was involved in renewable energy acquisitions after 1990. From about 1997 until I retired, I managed BPA's renewable energy program. I am

435

Genetics Home Reference: Dandy-Walker syndrome  

MedlinePLUS

... contains the cerebellum and the brainstem, called the posterior fossa, is abnormally large. These abnormalities often result ... neurological ; palsy ; paraplegia ; pattern of inheritance ; polydactyly ; population ; posterior ; sporadic ; syndactyly ; syndrome ; teratogens ; tissue ; trisomy ; urogenital tract ; ...

436

Familial Dandy-Walker malformation and leukodystrophy  

Microsoft Academic Search

We report the first familial cases with two different types of posterior fossa cystic malformation and a leukodystrophic-like aspect on cerebral magnetic resonance imaging (MRI). The girl and her brother had severe encephalopathy, marked hypotonia, absent deep tendon reflexes, macrocrania, gigantism, and dysmorphic face and extremities. The girl had generalized seizures. The boy had unilateral cataract and bilateral optic atrophy.

Véronique T. Humbertclaude; Philippe A. Coubes; Nicolas Leboucq; Bernard B. Echenne

1997-01-01

437

Mark Walker Director of Public Affairs  

E-print Network

what markets, market volatility, future supply-constrained, and higher growth conditions may cause), this report is not accounting for the demand-supply inequity that is going to affect global economies approaches are now more sophisticated than this and would account for specific other market factors

438

A Smart Walker to Understand Walking Abilities  

E-print Network

· No standardized procedure · Common clinical measures: ­ Timed Up and Go (TUG) ­ Berg Balance Scale (BBS) ­ Center is balance control affected? ­ What are the challenges? · Can we assess walking abilities in a naturalistic to decrease performance #12;15 Lower Limb Balance Control #12;16 Upper Limb Balance Control · Center

Poupart, Pascal

439

October 3, 2006 TO: Mark Walker  

E-print Network

salmon (Oncorhynchus tshawytscha) identified at stream kilometer 3.59 (near the confluence of Little (Oncorhynchus mykiss). 0. mykiss constituted the highest species biomass within Big Canyon Creek. One chinook

440

Mark Walker Director of Public Affairs  

E-print Network

's Conservation Planning Assumptions," the region is acquiring conservation at a much faster pace than the Plan their pace of acquiring efficiency, BPA can too. Together we should be able to get 30-40% more cost-effective energy efficiency by 2023 than expected. It is critical that we continue at or beyond the present pace

441

Motion-reversal in colloidal walkers  

E-print Network

In this research, the manipulation of colloidal systems composed of superparamagnetic particles in water is studied by a simulation method. In response to an external magnetic field, the dipoles drive the beads to self-assemble ...

Su, Yi-Han, S.B. Massachusetts Institute of Technology

2013-01-01

442

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

443

Walker-Breaker games Lisa Espig  

E-print Network

grant ccf1013110, Email lespig@andrew.cmu.edu. Department of Mathematical Sciences, Carnegie Mellon of Mathematical Sciences, Carnegie Mellon University, Pittsburgh PA15213, USA. Research sup- ported in part by NSF@post.tau.ac.il. § Department of Mathematical Sciences, Carnegie Mellon University, Pittsburgh PA15213, USA. Research sup

Frieze, Alan

444

________________________________________________________________________The MIND Institute__________________ Cheryl K. Walker, MD  

E-print Network

Collge, Northampton, MA 1980 MD, University of California, San Francisco, CA 1985 Residency in Obstetrics of infections and immunologic responses in reproductive health and pregnancy outcomes. She transitioned her influences of maternal physiology, medical conditions and obstetric interventions on neurodevelopmental

Nguyen, Danh

445

Genetics Home Reference: Walker-Warburg syndrome  

MedlinePLUS

... proteins and other molecules outside the cell (extracellular matrix). In skeletal muscles, the anchoring function of ?- ... cell ; cerebellum ; congenital ; cytoskeleton ; disability ; dysplasia ; extracellular ; extracellular matrix ; gene ; glycosylation ; hydrocephalus ; hypotonia ; inherited ; muscle cells ; muscle ...

446

Mark E. Walker January 15, 2012  

E-print Network

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

Logan, David

447

Mark E. Walker January 6, 2006  

E-print Network

", (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

Walker, Mark

448

WALKER REPORTING SERVICE (724) 224-5282  

E-print Network

that's caused some angst and some concern amongst members of this community. I #12;1 2 3 4 5 6 7 8 9 10 communicating. That's my fault and that shouldn't happen. We'll learn from that. And that happened, we normally of my key individuals, Dan's boss, is deployed out as part of the Corps of Engineers hurricane Sandy

US Army Corps of Engineers

449

Mark Walker Director of Public Affairs  

E-print Network

. A nuclear power plant only needs water for cooling and does not generate more global warming pollution can easily be distributed. I also believe nuclear power needs to be given much higher priority and replaced with either coal or nuclear. Oil is best used for transportation needs. Several years ago

450

Activated Random Walkers: Facts, Conjectures and Challenges  

NASA Astrophysics Data System (ADS)

We study a particle system with hopping (random walk) dynamics on the integer lattice ? d . The particles can exist in two states, active or inactive (sleeping); only the former can hop. The dynamics conserves the number of particles; there is no limit on the number of particles at a given site. Isolated active particles fall asleep at rate ?>0, and then remain asleep until joined by another particle at the same site. The state in which all particles are inactive is absorbing. Whether activity continues at long times depends on the relation between the particle density ? and the sleeping rate ?. We discuss the general case, and then, for the one-dimensional totally asymmetric case, study the phase transition between an active phase (for sufficiently large particle densities and/or small ?) and an absorbing one. We also present arguments regarding the asymptotic mean hopping velocity in the active phase, the rate of fixation in the absorbing phase, and survival of the infinite system at criticality. Using mean-field theory and Monte Carlo simulation, we locate the phase boundary. The phase transition appears to be continuous in both the symmetric and asymmetric versions of the process, but the critical behavior is very different. The former case is characterized by simple integer or rational values for critical exponents ( ?=1, for example), and the phase diagram is in accord with the prediction of mean-field theory. We present evidence that the symmetric version belongs to the universality class of conserved stochastic sandpiles, also known as conserved directed percolation. Simulations also reveal an interesting transient phenomenon of damped oscillations in the activity density.

Dickman, Ronald; Rolla, Leonardo T.; Sidoravicius, Vladas

2010-02-01

451

Media Inquiries: Department of Communications Michael Walker, 212-769-5766; walker@amnh.org  

E-print Network

after the Arizona wildfires of last year? Are non-native fish endangering brook trout in Lake Champlain Hero, Vermont o Found that the eggs of native brook trout populations in the Lake Champlain basin were

Walter, M.Todd

452

Evolutionary Ecology, 1994, 8, 188-195 Pollen availability, seed production and seed  

E-print Network

, Cirsium arvense. Offspring of flies feed solelyon thistle seeds and seed production is pollen- limited thistle (Cirsium arvense) may be affected by the availability of pollen. In Europe, O. ruficauda attacks

Lalonde, Bob

454

74 FR 45704 - Safety Standard for Infant Walkers  

Federal Register 2010, 2011, 2012, 2013, 2014

...amputation, crushing, lacerations, fractures, hematomas, bruises, or other injuries to fingers, toes, or other parts of the anatomy of young children.'' 16 CFR 1500.18(a)(6). The regulations set out mechanical, labeling, and recordkeeping...

2009-09-03

455

Alice Walker's Politics or the Politics of the Color Purple  

Microsoft Academic Search

I know very well that after this diagnosis the reader now expects remedies. I did not conceive of this book as a work of protest or even as a search for solutions. It was born out of reflections on an accepted failure [Memmi, 1965: 145]. Away with racism! Away with colonialism! They smack too much of barbarism. M. Mannoni has

Cynthia Hamilton

1988-01-01

456

Passive walker that can walk down steps: simulations and experiments  

NASA Astrophysics Data System (ADS)

A planar passive walking model with straight legs and round feet was discussed. This model can walk down steps, both on stairs with even steps and with random steps. Simulations showed that models with small moments of inertia can navigate large height steps. Period-doubling has been observed when the space between steps grows. This period-doubling has been validated by experiments, and the results of experiments were coincident with the simulation.

Liu, Ning; Li, Junfeng; Wang, Tianshu

2008-10-01

457

BY MEG WALKER Did David Ng's dad beat  

E-print Network

interested in development generally and other issues related to global sustenance and social responsibility) followed. All are connected to the central concept of "talking science" though usually in unexpected ways magazine fills a similar gap between geek-talk and social conversations around technology. "I think a lot

Farrell, Anthony P.

458

Artificial Tribotactic Microscopic Walkers: Walking Based on Friction Gradients  

NASA Astrophysics Data System (ADS)

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.

Steimel, Joshua P.; Aragones, Juan L.; Alexander-Katz, Alfredo

2014-10-01

459

Contact line treatment with the sharp interface method Claudio Walker  

E-print Network

the geometric information is required. Spelt [22] proposed a method to treat contact points in diffuse interface of Spelt's method to a sharp interface method. Equations Navier-Stokes equations We consider incompressible

Müller,Bernhard

460

BY MEG WALKER If there's a good wind up, West  

E-print Network

on the water. That's not unusual for a sailor. But what is unusual is that Girke is one of the few athletes who community will participate in the 2008 Beijing Olympic and Paralympic Games as athletes, coaches sports 8 #12;Landmark sex exploitation study finds surprising number of female abusers The results

Farrell, Anthony P.

461

On the conjecture of Kevin Walker Michael Farber  

E-print Network

in topological robotics as the configuration space of the planar linkage, a simple mechanism consisting of n bars [16] and the Japanese school (see, e.g. [10]). The Betti numbers of M as func- tions of the length

Wirosoetisno, Djoko