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1

Three osculating walkers  

Microsoft Academic Search

We consider three directed walkers on the square lattice, which move simultaneously at each tick of a clock and never cross. Their trajectories form a non-crossing configuration of walks. This configuration is said to be osculating if the walkers never share an edge, and vicious (or: non-intersecting) if they never meet. We give a closed form expression for the generating

Mireille Bousquet-Mélou

2006-01-01

2

Using a walker  

MedlinePLUS

... wheels of your walker are touching the ground. Lean slightly forward and use your arms to help ... grab the armrest, bed, or toilet behind you. Lean forward and move your weaker leg forward (the ...

3

Test and Evaluation of Baby Walkers and Walker-Jumpers.  

National Technical Information Service (NTIS)

Accident reports from hospital emergency rooms were surveyed to determine the probable causes of accidents involving baby walkers and walker-jumpers. Test methods were developed to simulate service conditions to determine if the characteristics leading to...

D. J. Chwirut

1974-01-01

4

Baby walker injuries.  

PubMed

In a study of 49 children between the ages of 8 and 14 months, parents were surveyed with a written questionnaire and a follow-up phone interview to determine the utilization of baby walkers and the frequency and severity of baby walker injuries. Most respondents (86%) placed their children in various types of baby walkers between 4 months and 1 year of age. Half of the 42 infants who used walkers experienced at least one accident involving a tip over, a fall down stairs, or finger entrapment. Two of those accident resulted in injuries serious enough to require medical management. Both infants sustained head and neck injuries after falling down stairs in a walker. Whereas stairway and finger entrapment accidents occurred before the age of 7 months, tip overs were much more likely to occur after the age of 8 months. Injuries are more common but less severe than previously reported. Pediatricians and other child health advocates can inform parents about the health risks, encourage regulatory agencies to improve product labeling, and stimulate manufacturers to adjust the product to age and weight specifications of the growing infant. PMID:7088607

Fazen, L E; Felizberto, P I

1982-07-01

5

Injuries associated with infant walkers.  

PubMed

In 1999, an estimated 8800 children younger than 15 months were treated in hospital emergency departments in the United States for injuries associated with infant walkers. Thirty-four infant walker-related deaths were reported from 1973 through 1998. The vast majority of injuries occur from falls down stairs, and head injuries are common. Walkers do not help a child learn to walk; indeed, they can delay normal motor and mental development. The use of warning labels, public education, adult supervision during walker use, and stair gates have all been demonstrated to be insufficient strategies to prevent injuries associated with infant walkers. To comply with the revised voluntary standard (ASTM F977-96), walkers manufactured after June 30, 1997, must be wider than a 36-in doorway or must have a braking mechanism designed to stop the walker if 1 or more wheels drop off the riding surface, such as at the top of a stairway. Because data indicate a considerable risk of major and minor injury and even death from the use of infant walkers, and because there is no clear benefit from their use, the American Academy of Pediatrics recommends a ban on the manufacture and sale of mobile infant walkers. If a parent insists on using a mobile infant walker, it is vital that they choose a walker that meets the performance standards of ASTM F977-96 to prevent falls down stairs. Stationary activity centers should be promoted as a safer alternative to mobile infant walkers. PMID:11533353

2001-09-01

6

Three osculating walkers  

NASA Astrophysics Data System (ADS)

We consider three directed walkers on the square lattice, which move simultaneously at each tick of a clock and never cross. Their trajectories form a non-crossing configuration of walks. This configuration is said to be osculating if the walkers never share an edge, and vicious (or: non-intersecting) if they never meet. We give a closed form expression for the generating function of osculating configurations starting from prescribed points. This generating function turns out to be algebraic. We also relate the enumeration of osculating configurations with prescribed starting and ending points to the (better understood) enumeration of non-intersecting configurations. Our method is based on a step by step decomposition of osculating configurations, and on the solution of the functional equation provided by this decomposition.

Bousquet-Mélou, Mireille

2006-06-01

7

Interview with Bruce Walker  

NSDL National Science Digital Library

This four minute, fifty-six second video from Howard Hughes Medical Institute presents an interview with Dr. Walker. It is available in QuickTime (MOV) and Windows Media (WMV) formats. It is featured on the 2007 Holiday Lectures DVD: AIDS: Evolution of an Epidemic available free from HHMI. This and other infectious disease videos can also be found at: http://www.hhmi.org/biointeractive/disease/video.html.

Howard Hughes Medical Institute (HHMI;)

2008-05-30

8

Dissimilar bouncy walkers.  

PubMed

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

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

2011-01-28

9

Dissimilar bouncy walkers  

NASA Astrophysics Data System (ADS)

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

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

2011-01-01

10

Baby walkers: paediatricians' knowledge, attitudes, and health promotion.  

PubMed

Paediatricians were surveyed about baby walker knowledge, attitudes, and practice. Advising about walkers was associated with working in community paediatrics, treating walker related injuries, knowledge about walkers, and positive attitudes towards walker health promotion. Greater knowledge about walkers was associated with more negative attitudes to walkers. Educating paediatricians and parents about the risks of, and alternatives to using walkers is important. PMID:14670775

Rhodes, K; Kendrick, D; Collier, J

2003-12-01

11

Evaluation of Walkers for Elderly People.  

National Technical Information Service (NTIS)

The aim of this study was to evaluate three types of walkers for elderly people, Four elderly patients participated in the study. The experiments were performed using three walkers: a familiar conventional folding walker, a caster walker and a power-assis...

T. Tamura M. Sekine H. Kuno M. Fujie A. Mori

2001-01-01

12

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

13

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

14

Obituary: Robert Mowbray Walker, 1929-2004  

Microsoft Academic Search

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.

Neil T. Schoenherr

2004-01-01

15

Baby walker-related injuries.  

PubMed

A retrospective review of charts of patients with baby walker-related injuries presenting to a large urban emergency room over a 23-month period was undertaken. Ninety-seven percent of the children sustained injuries to their head or face. Sixty-eight percent of the injuries were the result of falling down steps. Twenty-two percent of the injuries required surgical or dental evaluation in addition to pediatric evaluation. PMID:6692642

Wellman, S; Paulson, J A

1984-02-01

16

A Reflection Principle for Three Vicious Walkers  

Microsoft Academic Search

We establish a reflection principle for three lattice walkers and use this\\u000aprinciple to reduce the enumeration of the configurations of three vicious\\u000awalkers to that of configurations of two vicious walkers. In the combinatorial\\u000atreatment of two vicious walkers, we make connections to two-chain watermelons\\u000aand to the classical ballot problem. Precisely, the reflection principle leads\\u000ato a bijection

William Y. C. Chen; Donna Q. J. Dou; Terence Y. J. Zhang

2008-01-01

17

Intussusception following a baby walker injury.  

PubMed

Serious abdominal injury as a result of a fall in a baby walker has not been previously reported. We present the case of a 13-month-old boy who developed intussusception following a fall down five stairs in a baby walker. Attempted hydrostatic reduction was unsuccessful. At operation, a bowel wall hematoma, serving as a lead point, was identified. This case adds another type of injury to the list of those previously associated with baby walker use. PMID:10195485

Conners, G P; Weber, C E; Emmens, R W

18

Parental decisions to use infant walkers  

PubMed Central

Design/methods—Caretakers of children attending a residents' continuity practice during a one month period were invited to participate in a structured interview to assess various aspects of infant safety. Ten questions specifically addressed infant walkers and the decision to acquire one; seven questions collected demographic data. Results—One hundred and fifty four primary caretakers participated. Of these, 77% (n=119) of caretakers used infant walkers for their child. For children who were not first born, 85% of caretakers had used walkers with their other children. No statistically significant differences were found between walker users and non-users with respect to the sex or birth order of the child, race, education, or (type of) caretaker. Also, no differences were found between these groups with respect to having received safety information from the pediatrician. For users, 97% heard about walkers before their baby's birth, but 65% did not decide to use one until after the birth. In addition, 61% of walker users stated that no one influenced their decision to get a walker and 75% bought their own. These decisions were not affected by caretaker education or birth order of the child. Finally, 78% believed that walkers were beneficial, and 72% believed that walker use accelerated development of independent walking skills. Conclusions—Mothers purchased walkers because of no uniformed perception of benefit. A period of time, up to several months in length, exists from when the first mother hears about walkers until she decides to purchase one. Until legislation can be passed banning walkers, this period of time may provide a window of opportunity for appropriate anticipatory guidance in the form of intense media assisted, antiwalker campaigns.

Bar-on, M.; Boyle, R.; Endriss, E

1998-01-01

19

Infant walker use, injuries, and motor development.  

PubMed Central

OBJECTIVES: To study the impact of infant walker use on motor development and injuries. POPULATION: One hundred and eighty five parents or primary care givers who attended a Singapore government polyclinic from September 1993 to February 1994, with their infants between 7 to 10 months, for a developmental assessment session. SETTING: A government polyclinic in Singapore. METHODS: The parent or primary care giver answered questions pertaining to infant walker use and injuries attributed to its use. Each infant was then given the Singapore modified version of the Denver Developmental Screening Test (DDST-S), along with a full clinical examination; both testers were blinded to walker use. RESULTS: One hundred and sixty seven (90%) of 185 infants used walkers regularly, and 21 (12.5%) of the users had one or more injuries. Most injuries were minor, such as bruises and swellings on the head, forehead, face, and cheeks. None of the children who did not use walkers showed any abnormal DDST-S results whereas 18 (10.8%) of the 167 walker users had either abnormal or questionable DDST-S results. CONCLUSIONS: 12.5% of walker users had one or more injuries and walker use may also delay the child's motor development. These findings will help the physician or nurse in primary care settings to advise parents about the potential hazards of walker use.

Thein, M. M.; Lee, J.; Tay, V.; Ling, S. L.

1997-01-01

20

Wet granular walkers and climbers  

NASA Astrophysics Data System (ADS)

We have observed that when a bidisperse mixture of glass beads is moistened by a fluid and shaken sinusoidally in a vertical container, small clusters of beads take off from the surface of the pile and rapidly climb up the container walls against gravity. These self-organized clus- ters are held together and against the wall by liquid capillary bridges, and are led by one large grain with one or more small grains trailing behind. When similar clusters are placed on a horizontally vibrating substrate they self-align and travel horizontally along the axis of vibration with a ratchet-like motion. We report a detailed experimental study performed for the simplest walker system consisting of one large and one small bead, and present a simple model that accounts for the observed behavior. Reference: Z.S. Khan et al.,New J. Phys 13, 053041 (2011).

Khan, Zeina S.; Steinberger, Audrey; Seemann, Ralf; Herminghaus, Stephan

2012-02-01

21

Walker, Uncle Will, and I: A Homophobe and Two Queens  

Microsoft Academic Search

The noted novelist Walker Percy (1916–1990) endured the suicides of his grandfather, father, and mother during his childhood. His cousin William Alexander Percy (1885–1942) adopted Walker and his two brothers following those tragedies. “Uncle Will” took great interest in the education of his adoptive sons. Walker in particular benefited from this; later in life, Walker and his good boyhood friend,

William Armstrong Percy III; Aidan Flax-Clarke; Lewis Gannett

2009-01-01

22

A Robotically-Augmented Walker for Older Adults  

Microsoft Academic Search

Many older adults use walkers to improve their stability and safety while walking. We have developed a robotically augmented walker to reduce fall risk and confusion, and to increase walker convenience and enjoyment. Using a modified version of the CARMEN navigation software suite (11), the walker is capable of parking itself and returning to the user when signaled by remote

Jared Glover; David Holstius; Michael Manojlovich; Keirsten Montgomery; Aaron Powers; Jack Wu; Sara Kiesler; Judith Matthews; Sebastian Thrun

23

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

2013-05-30

24

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

25

Baby walkers . . . time to take a stand?  

PubMed Central

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 in the design of baby walkers. Images Fig. 1 Fig. 2 Fig. 3

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

1987-01-01

26

Vicious walkers, friendly walkers and Young tableaux: II. With a wall  

Microsoft Academic Search

We derive new results for the number of star and watermelon configurations of vicious walkers in the presence of an impenetrable wall by showing that these follow from standard results in the theory of Young tableaux and combinatorial descriptions of symmetric functions. For the problem of n friendly walkers, we derive exact asymptotics for the number of stars and watermelons,

Christian Krattenthaler; Anthony J. Guttmann; Xavier G. Viennot

2000-01-01

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

Attitudes to and use of baby walkers in Dublin.  

PubMed Central

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 main reasons for doing so included babies' enjoyment of them and the fact that the walker was used for an older sibling. Although none of the users listed safety concerns as a reason to stop using the walker, non-users (45%) did so; 12.5% of the users had at least one walker related injury. CONCLUSIONS: Parents of babies who use a walker perceive them as beneficial. However these babies are placed at unnecessary risk. It behoves all health professionals and child carers to alert parents to these dangers and the sale of walkers should be reviewed.

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

1995-01-01

29

Risks of Baby Walkers and Options for Prevention  

PubMed Central

Recent studies have reported fatal head injuries associated with baby walkers. Skull fractures and hospital admissions are significantly higher for infants who have received head injuries while using a walker. Thirty to 50% of infants regularly placed in walkers experience an accident or injury related to the device. Most injuries are minor cuts, abrasions and contusions. While there are many hazards, no benefits have been documented. The walkers do not help children learn to walk. Options for preventing injury including banning baby walkers, product design regulations, and public education about the risks. An outright ban would be difficult, because walkers are not considered inherently dangerous; they become so when parental supervision is lacking. Although design specifications will decrease some walker-related injuries, they will not prevent severe or fatal head injuries associated with falls down stairs. Public awareness of hazards from baby walkers and discouragement of their use are recommended preventive measures at this time.

Aziz, Alnoor; McIntyre, Lynn; Khazen, Roch

1985-01-01

30

Vicious walkers and directed polymer networks in general dimensions  

Microsoft Academic Search

A number, p, of vicious random walkers on a D-dimensional lattice is considered. ``Vicious walkers'' describes the situation when two or more walkers arrive at the same lattice site and annihilate one another, and consequently their walks terminate. In certain cases the generating function R(u)[S(u)] for the number of configurations Rs[Ss] of walkers which reunite [survive] after s steps is

J. W. Essam; A. J. Guttmann

1995-01-01

31

Walker Calhoun: Cherokee Song and Dance Man. Interview.  

ERIC Educational Resources Information Center

Born in 1918, the youngest of 12 children, Walker Calhoun describes growing up on the Cherokee Reservation in North Carolina. The schools turned the Cherokee against their old ways, but Walker learned many old songs and dances from his uncle, Will West. Since retirement, Walker has taught the dances and songs to children. His material has been…

Olson, Ted

1995-01-01

32

Baby walkers —an underestimated hazard for our children?  

Microsoft Academic Search

Baby walkers (BWs) continue to be a frequent cause of head injuries in young children. A random sample survey of 240 families with children aged 2–6 years revealed a use rate of bady walkers of 55%. Of the children using baby walkers 20% were found to have suffered a BW-related accident. In a retrospective study we reviewed 172 case reports

J. Mayr; M. Gaisl; K. Purtscher; H. Noeres; G. Schimpl; G. Fasching

1994-01-01

33

Unusual manifestation of Marden-Walker syndrome.  

PubMed

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

2012-05-01

34

ZERO DYNAMICS OF UNDERACTUATED PLANAR BIPED WALKERS  

Microsoft Academic Search

The zero dynamics of a hybrid model of bipedal walking are introduced and studied for a class of N-link, planar robots with one degree of underactuation and outputs that depend only on the conflguration variables. Asymptotically stable solutions of the zero dynamics correspond to asymptotically stabilizable orbits of the full hybrid model of the walker. The Poincare map of the

E. R. Westervelt; J. W. Grizzle; D. E. Koditschek

2002-01-01

35

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.

36

Reservoir description, Walker Creek field, Arkansas  

Microsoft Academic Search

A multidisciplinary reservoir description of Walker Creek field in southern Arkansas was conducted to evaluate the field's potential and determine the best method of increasing recovery. The reservoir is within a 100-ft-thick section of the ooid grainstone facies of the Jurassic Smackover Formation. The reservoir is currently under partial pressure maintenance by reinjection of produced gas at the crest of

D. M. Bliefnick; K. M. Frey; Thu-Thuy Dang; S. M. Bissmeyer

1990-01-01

37

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.

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

2012-01-01

38

Rehabilitation Walker System with Standing Assistance Device  

Microsoft Academic Search

This paper proposes a walker system with power assistance device for standing up motion. Our system focuses on family use for aged person who needs nursing in their daily life. Our key ideas are two topics. The first topic is new assistance manipulator mechanism with four parallel linkages. Our proposed manipulator mechanism requires only smaller actuators and realizes rigid structure

Daisuke Chugo; Wataru Matsuoka; Songmin Jia; Kunikatsu Takase

2007-01-01

39

Vicious walkers, friendly walkers and Young tableaux: II. With a wall  

NASA Astrophysics Data System (ADS)

We derive new results for the number of star and watermelon configurations of vicious walkers in the presence of an impenetrable wall by showing that these follow from standard results in the theory of Young tableaux and combinatorial descriptions of symmetric functions. For the problem of n friendly walkers, we derive exact asymptotics for the number of stars and watermelons, both in the absence of a wall and in the presence of a wall.

Krattenthaler, Christian; Guttmann, Anthony J.; Viennot, Xavier G.

2000-12-01

40

Baby walker related injuries--a continuing problem.  

PubMed Central

Baby walkers have been associated with burns, head trauma and other types of injury. A retrospective study of all infants under the age of two years attending an accident and emergency unit demonstrated 22 injuries associated with baby walkers from a total of 1049 attendances. The most serious injuries were three skull fractures, with the most common mechanism being of a fall downstairs in the walker. Injury while in a baby walker occurred with a similar frequency to injury due to road traffic accidents. We conclude that despite previous warnings Baby Walkers still represent a considerable hazard to infants.

Coats, T J; Allen, M

1991-01-01

41

Baby walker related injuries--a continuing problem.  

PubMed

Baby walkers have been associated with burns, head trauma and other types of injury. A retrospective study of all infants under the age of two years attending an accident and emergency unit demonstrated 22 injuries associated with baby walkers from a total of 1049 attendances. The most serious injuries were three skull fractures, with the most common mechanism being of a fall downstairs in the walker. Injury while in a baby walker occurred with a similar frequency to injury due to road traffic accidents. We conclude that despite previous warnings Baby Walkers still represent a considerable hazard to infants. PMID:1854395

Coats, T J; Allen, M

1991-03-01

42

Using walker during walking: a pilot study for health elder.  

PubMed

Walker operation completely relies on the walker handle, however most marketed walkers possess two horizontal handles. Several researchers have suggested that horizontal handles might lead to wrist injury. Therefore, the purpose of this study is to assess the relevant design aspects of walker for elderly people. 28 elders participated in this study; when the experiment was started, subject walked on the tile for 3 meter distance twice by using walker. Data for analysis were selected at the corresponding wrist deviation and vertical force. The results showed that during walker using, the mean wrist deviation was greater than zero. The largest vertical force is significantly larger than the smallest one, and different wrist deviation occurred at three phases, the largest wrist deviation while raising walker is larger than the smallest one, however, no significant different was found between the largest and smallest wrist deviation while pressing walker. No significant correlation occurred between weight and wrist deviation. The correlation between weight and vertical force was significantly positive. With wrist deviation walker use may cause injury to upper-limb, however wrists remain in a neutral position during hand movement to prevent damage. The findings of this study should improve the design of walker handles to reduce the wrist deviations of users. PMID:22317023

Po-Chan, Yeh; Cherng-Yee, Leung

2012-01-01

43

Head injuries related to the use of baby walkers.  

PubMed Central

To determine what proportion of head injuries in children under 24 months of age who presented to an emergency department were related to the use of baby walkers, we reviewed the charts of 52 such children. Walkers were involved in 42% of the head injuries in the children under 12 months of age and in none of those in the children aged 12 to 24 months. All walker-related injuries, including skull fractures in three children, involved stairs (p less than 0.001). Questionnaires were also sent to all families with children aged 3 to 18 months attending a private pediatric practice to determine the prevalence of falls involving baby walkers among these children and the factors associated with such falls. Of the 152 responding families 82% reported using or having used a walker. Thirty-six percent of the families reported that their child had a fall while in a walker, with 8.8% of the falls resulting in contact with a doctor. Walker-related falls were directly associated with time spent in the walker (p less than 0.001) and with a previous fall from the walker by an older sibling (p less than 0.03). Since there is no demonstrated benefit of walkers, their use should not be encouraged, and parents should be advised of their potential danger.

Stoffman, J M; Bass, M J; Fox, A M

1984-01-01

44

Modeling a self-propelled autochemotactic walker  

NASA Astrophysics Data System (ADS)

We develop a minimal model for the stochastic dynamics of microorganisms where individuals communicate via autochemotaxis. This means that microorganisms, such as bacteria, amoebae, or cells, follow the gradient of a chemical that they produce themselves to attract or repel each other. A microorganism is represented as a self-propelled particle or walker with constant speed while its velocity direction diffuses on the unit circle. We study the autochemotactic response of a single self-propelled walker whose dynamics is non-Markovian. We show that its long-time dynamics is always diffusive by deriving analytic expressions for its diffusion coefficient in the weak- and strong-coupling case. We confirm our findings by numerical simulations.

Taktikos, Johannes; Zaburdaev, Vasily; Stark, Holger

2011-10-01

45

Brownian walkers within subdiffusing territorial boundaries  

NASA Astrophysics Data System (ADS)

Inspired by the collective phenomenon of territorial emergence, whereby animals move and interact through the scent marks they deposit, we study the dynamics of a 1D Brownian walker in a random environment consisting of confining boundaries that are themselves diffusing anomalously. We show how to reduce, in certain parameter regimes, the non-Markovian, many-body problem of territoriality to the analytically tractable one-body problem studied here. The mean square displacement (MSD) of the 1D Brownian walker within subdiffusing boundaries is calculated exactly and generalizes well known results when the boundaries are immobile. Furthermore, under certain conditions, if the boundary dynamics are strongly subdiffusive, we show the appearance of an interesting nonmonotonicity in the time dependence of the MSD, giving rise to transient negative diffusion.

Giuggioli, L.; Potts, J. R.; Harris, S.

2011-06-01

46

Precise asymptotics for a random walker's maximum  

Microsoft Academic Search

We consider a discrete time random walk in one dimension. At each time step the walker jumps by a random distance, independent from step to step, drawn from an arbitrary symmetric density function. We show that the expected positive maximum E[Mn] of the walk up to n steps behaves asymptotically for large n as E[M_n]\\/\\\\sigma=\\\\sqrt {2n\\/\\\\pi }+\\\\gamma+\\\\Or (n^{-1\\/2}) , where

Alain Comtet; Satya N. Majumdar

2005-01-01

47

Time Walkers and Spatial Dynamics of Aging Information  

NASA Astrophysics Data System (ADS)

The distribution of information is essential for a living system’s ability to coordinate and adapt. Random walkers are often used to model this distribution process and, in doing so, one effectively assumes that information maintains its relevance over time. But the value of information in social and biological systems often decays and must continuously be updated. To capture the spatial dynamics of aging information, we introduce time walkers. A time walker moves like a random walker, but interacts with traces left by other walkers, some representing older information, some newer. The traces form a navigable information landscape which we visualize as a river network. We quantify the dynamical properties of time walkers, and the quality of the information left behind, on a two-dimensional lattice. We show that searching in this landscape is superior to random searching.

Lizana, L.; Rosvall, M.; Sneppen, K.

2010-01-01

48

Three Attractive Osculating Walkers and a Polymer Collapse Transition  

Microsoft Academic Search

Consider n interacting lock-step walkers in one dimension which start at the points {0,2,4,...,2(n-1)} and at each tick of a clock move unit distance to the left or right with the constraint that if two walkers land on the same site their next steps must be in the opposite direction so that crossing is avoided. When two walkers visit and

John W. Essam

2003-01-01

49

Prevention strategies for infant walker-related injuries.  

PubMed Central

The estimated number of walker-related injuries to infants increased during the 1980s, and standards for walker design safety remain voluntary with no monitoring to assess compliance. Although banning the walker has been proposed, this prevention strategy has not been employed. The most recent statistics available indicate that there were an estimated 27,804 walker-related injuries requiring emergency room attention among ages 0-4 years in 1991. Results of a survey of parents of 3-12-month-olds indicated considerable use of walkers, with greater use among parents with lower educational levels. Reported reasons for using walkers were for the infant's entertainment, enjoyment, and containment, as well as to help infants learn to walk. The authors recommend the consideration of a series of preventive strategies according to the epidemiologic framework for injury control and prevention designed by William Haddon, Jr. These include, but are not limited to, prohibiting the manufacture and sale of the walker, mandatory standards, redesign of the walker, design of an alternative to the walker, and consumer education to reduce use and to change patterns of use.

Trinkoff, A; Parks, P L

1993-01-01

50

Conserved energy for Robertson-Walker spacetimes with scalar fields  

NASA Astrophysics Data System (ADS)

Energy for Robertson-Walker spacetimes is defined using the static Einstein spacetime as a reference space. The energy is shown to be equivalent to the dilatation operator. This leads to a useful formulation for the dynamics and for a quantum field theory on a classical Roberston-Walker spacetime; it also provides the basis for a microcanonical entropy.

Horwitz, G.; Katz, J.

1988-12-01

51

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

Federal Register 2010, 2011, 2012, 2013

...parameter of the step test is the velocity of a walker with a child in it...child maintains a 4 feet/second top speed, regardless of the walker's weight...staff believes that a 4 feet/second velocity should be maintained...

2010-06-21

52

16 CFR 1216.2 - Requirements for infant walkers.  

Code of Federal Regulations, 2013 CFR

...dummy, lb. Simulated speed, ft/s Apply tipover...Where Vf = Maximum velocity of walker at edge of...Where Vf = Maximum velocity of walker at edge of...sec Vo = Initial velocity = 0 WCAMI w/vest...seat. Set any manual speed control to the...

2013-01-01

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

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

55

The Robertson-Walker metrics expressible in static form.  

NASA Astrophysics Data System (ADS)

It is shown that there are six, and only six, Robertson-Walker metrics which can be expressed in static form. They are precisely those Robertson-Walker metrics whosespacetime curvature is constant. The coordinate transformations which transform these metrics into their static form are also given. An error in Robertson and Noonan's Book [1] is pointed out and corrected.

Florides, P. S.

1980-07-01

56

Two Cases of Walker-Warburg Syndrome Complicated by Hydrocephalus  

Microsoft Academic Search

Walker-Warburg syndrome is a very rare autosomal recessive disorder with congenital muscular dystrophy, brain malformations on the basis of a neuronal migration defect and ocular abnormalities. We report our experience in treating two cases of Walker-Warburg syndrome complicated by hydrocephalus with shunting and endoscopic techniques.

M. Preuss; M. Heckmann; M. Stein; U. Nestler

2010-01-01

57

Examining the contribution of infant walkers to childhood poisoning.  

PubMed

Parents frequently utilize baby walkers in their infants of approximately 5-15 mo of age and create opportunities for traumatic accidents. Healthcare professionals have tried to increase awareness of their dangers; despite this, between 1986 and 1991 reported walker-related accidents rose 45%. We determined if walkers were a significant contributor to childhood poisonings and what toxins were encountered most commonly. A 14-mo prospective study in a regional poison information center determined the prevalence of accidental pediatric poisonings in children aged 5-15 mo old who suffered their exposure while in a baby walker. The regional poison information center managed 7.058 poisoning exposures, 2.8% of which occurred while the child was in an infant walker. The mean age was 8.25 mo (range 5-14 mo), with 96% less than 12 mo. Substances involved were: plants 56.7%, cleaning products 9.9%, cosmetics 5.5%, construction supplies 5.0%, cigarettes 4.5%, topicals 4.5%, oral medications 2.0%, chalk 2.0% and miscellaneous 9.9%. The majority (95%) of children were asymptomatic. Infant walkers contributed substantially less to infant poisonings than was anticipated. Despite the innocuous nature of exposures, a vulnerable population was exposed to potential poisons within reach of their grasp. Baby walker injuries are not limited to trauma, and accidental poisonings should be included in the admonitions that accompany their use. PMID:10670086

Mroz, L S; Krenzelok, E P

2000-02-01

58

Do baby walkers delay onset of walking in young children?  

PubMed

Baby walkers have been a source of considerable controversy. Some people suggest developmental benefit from their use while others focus on the potential harm that stems from accidents and even suggest developmental delay. This mini-review aimed to determine if use of a baby walker delays affects the onset of walking. The Cochrane library, Embase, CINAHL and Medline were searched for randomized controlled trials (RCTs) and cohort studies, which compared the onset of walking in infants who used baby walkers with a group who did not. Two RCTs and two cohort studies were identified and available for consideration. All of the studies examined the effect of infant walkers on the onset of walking. The results of the two RCTs did not demonstrate a significant effect on the onset of walking. The cohort studies suggest that the use of infant walkers delayed the onset of walking in young children and a pooled analysis of the four studies suggested a delay of between 11 and 26 days. Although the quality of the studies was relatively poor these studies lend no support to the argument that walkers aid the development of walking. The significance of a delay of this magnitude is however unclear. Further work is required to determine whether walkers are an independent causal factor in accidents. PMID:12447120

Burrows, Patricia; Griffiths, Peter

2002-11-01

59

Familial Dandy-Walker malformation and leukodystrophy.  

PubMed

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. The parents were first cousins, suggesting autosomal recessive transmission. MRI showed Dandy-Walker variant in the girl, with cerebellar vermis hypoplasia and expansion of the cisterna magna, which communicated with the fourth ventricle. Her brother had mega cisterna magna communicating with the fourth ventricle and a normal cerebellum. The 2 children had abnormally high signal in the supratentorial white matter. Visual and auditory evoked potentials revealed prolonged latencies. Motor and sensory conduction velocities were normal. Muscle and nerve biopsies were normal. Metabolic exploration demonstrated no abnormality. PMID:9258968

Humbertclaude, V T; Coubes, P A; Leboucq, N; Echenne, B B

1997-05-01

60

"Oh Freedom"--Women and History in Margaret Walker's "Jubilee"  

ERIC Educational Resources Information Center

Discusses the way in which Margaret Walker's novel "Jubilee" successfully portrays black American history during the period of slavery, the Civil War years, and Reconstruction, as seen by the women who lived it. (GW)

Klotman, Phyllis Rauch

1977-01-01

61

Complete maximal surfaces in static Robertson Walker 3-spaces  

NASA Astrophysics Data System (ADS)

We construct a large family of complete maximal surfaces in the static Robertson Walker 3-spaces with negative base curvature. These examples provide a wide variety of non-standard foliations of such spaces by entire maximal graphs.

Fernández, Isabel; Mira, Pablo

2007-12-01

62

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

63

Hazards of baby walkers in a European context.  

PubMed Central

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: 49 babies with baby walker related injuries brought to the emergency clinics during the period May 1994 to April 1995. RESULTS: The incidence of these injuries was 16 per thousand person years of users, or 3.5 per thousand babies per year. More boys than girls were brought to the hospital for these injuries and the incidence density was highest during the ninth and 10th month of age. Falls from heights, particularly stairs, were the most frequent cause of baby walker related injuries, especially among younger babies. The majority of these injuries were of minor severity, but three babies had bone fractures and one had a second degree facial burn. Six babies required hospitalization and for seven others, a follow up visit was needed. The higher proportion of hospitalization among girls than boys raises the possibility that boys with minor injuries are more frequently brought to the hospital. CONCLUSIONS: Baby walkers impart a significant risk of injury from a consumer product that provides no clearly identifiable benefit. As most baby walker injuries happen on stairs, modifications in product design are required to reduce these injuries. Moreover, parents should be forcefully advised of the risks and predisposing conditions, if baby walkers are to be used at all.

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

1996-01-01

64

Reservoir description, Walker Creek field, Arkansas  

SciTech Connect

A multidisciplinary reservoir description of Walker Creek field in southern Arkansas was conducted to evaluate the field's potential and determine the best method of increasing recovery. The reservoir is within a 100-ft-thick section of the ooid grainstone facies of the Jurassic Smackover Formation. The reservoir is currently under partial pressure maintenance by reinjection of produced gas at the crest of the structure. One of the goals of the study was to evaluate reservoir management options for effecting significant incremental oil recovery. The reservoir was originally divided into five producing zones (1-5). Of these, zones 2 and 4 account for nearly 95% of the production. The grainstone facies in zones 2 and 4 consist predominantly of ooids, but also contain peloids, oncolites, and intraclasts. Calcite cement creates discontinuous tight streaks throughout the reservoir. Porosity is predominantly intergranular and ranges from 1% to greater than 20%. Permeability also varies widely, ranging from 0.1 to > 5000 md. Five percent porosity and 0.6 md permeability, as determined by log analysis, were used as a net pay cutoff. Data from lithologic and log analyses were used to construct cross sections across the field. These sections and grainstone isopach maps illustrate that the two main reservoir zones represent two generations of prograding ooid shoal development. Calcite cemented intervals within the zones cannot be correlated beyond two or three wells. The local extent of these intervals does not justify using them to further subdivide the reservoir zones. Gross pay, net pay, and {delta}h maps indicate that development of porosity followed the trend and distribution of the ooid shoals. Production data (pressure plots, gas-to-oil-ratio maps, and tracer studies) suggest that individual reservoir zones are in communication across the field. These results led to a decision against infill drilling in the field.

Bliefnick, D.M.; Frey, K.M.; Dang, Thu-Thuy (ARCO Oil and Gas Co., Plano, TX (USA)); Bissmeyer, S.M. (ARCO Oil and Gas Co., Lafayette, LA (USA))

1990-05-01

65

Multiple Walkers in the Wang-Landau Algorithm  

SciTech Connect

The mean cost for converging an estimated density of states using the Wang-Landau algorithm is measured for the Ising and Heisenberg models. The cost increases in a power-law fashion with the number of spins, with an exponent near 3 for one-dimensional models, and closer to 2.4 for two-dimensional models. The effect of multiple, simultaneous walkers on the cost is also measured. For the one-dimensional Ising model the cost can increase with the number of walkers for large systems. For both the Ising and Heisenberg models in two-dimensions, no adverse impact on the cost is observed. Thus multiple walkers is a strategy that should scale well in a parallel computing environment for many models of magnetic materials.

Brown, G

2005-12-28

66

Mountain Trail Formation and the Active Walker Model  

NASA Astrophysics Data System (ADS)

We extend the active walker model to address the formation of paths on gradients, which have been observed to have a zigzag form. Our extension includes a new rule, which prohibits direct descent or ascent on steep inclines, simulating aversion to falling. Further augmentation of the model stops walkers from changing direction very rapidly as that would likely lead to a fall. The extended model predicts paths with qualitatively similar forms to the observed trails, but only if the terms suppressing sudden direction changes are included. The need to include terms into the model that stop rapid direction change when simulating mountain trails indicates that a similar rule should also be included in the standard active walker model.

Gilks, S. J.; Hague, J. P.

67

Smart random walkers: the cost of knowing the path.  

PubMed

In this work we study the problem of targeting signals in networks using entropy information measurements to quantify the cost of targeting. We introduce a penalization rule that imposes a restriction on the long paths and therefore focuses the signal to the target. By this scheme we go continuously from fully random walkers to walkers biased to the target. We found that the optimal degree of penalization is mainly determined by the topology of the network. By analyzing several examples, we have found that a small amount of penalization reduces considerably the typical walk length, and from this we conclude that a network can be efficiently navigated with restricted information. PMID:23005381

Perotti, Juan I; Billoni, Orlando V

2012-07-19

68

Exact Distribution of the Maximal Height of p Vicious Walkers  

NASA Astrophysics Data System (ADS)

Using path-integral techniques, we compute exactly the distribution of the maximal height Hp of p nonintersecting Brownian walkers over a unit time interval in one dimension, both for excursions p watermelons with a wall, and bridges p watermelons without a wall, for all integer p?1. For large p, we show that ?Hp?˜2p (excursions) whereas ?Hp?˜p (bridges). Our exact results prove that previous numerical experiments only measured the preasymptotic behaviors and not the correct asymptotic ones. In addition, our method establishes a physical connection between vicious walkers and random matrix theory.

Schehr, Grégory; Majumdar, Satya N.; Comtet, Alain; Randon-Furling, Julien

2008-10-01

69

10. Photocopy of photograph showing the three Walker sisters ginning ...  

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

10. Photocopy of photograph showing the three Walker sisters ginning cotton. Misses Hettie, Martha and Louisa are from left to right. The original photograph was taken on May 21, 1936 by Edouard E. Exline and is one of five photographs in the album, 'A Sketch of Mountain Life: Great Smoky Mountains National Park', compiled by Edouard E. Exline and C.S. Grossman. The album is on file at the Great Smoky Mountains National Park; the photograph number is III-A-HSE-9642. - Walker Family Farm (General views), Gatlinburg, Sevier County, TN

70

Factors associated with women's antenatal plans to use a baby walker: A cross sectional study  

Microsoft Academic Search

Objective The objective of these analyses was to explore maternal antnatal decisions about baby walker use, factors associated with these decisions and the relationship between antenatal plans to use a walker and postnatal walker use.Design Cross sectional study.Setting Mothers-to-be (n = 1174) participating in a cluster randomised controlled trial of an educational package to reduce walker use in 64 general

Rachel Illingworth; Denise Kendrick; Jacqueline Collier; Amanda Woods; Kim Wattse; Michael Dewey; Chih-Mei Chen

2006-01-01

71

Vicious random walkers and a discretization of Gaussian random matrix ensembles  

Microsoft Academic Search

The vicious random walker problem on a one-dimensional lattice is considered. Many walkers take simultaneous steps on the lattice and the configurations in which two of them arrive at the same site are prohibited. It is known that the probability distribution of N walkers after M steps can be written in a determinant form. Using an integration technique borrowed from the

Taro Nagao; Peter J. Forrester

2002-01-01

72

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.

73

75 FR 24753 - The Walker Auto Group, Inc., Miamisburg, OH; Notice of Negative Determination Regarding...  

Federal Register 2010, 2011, 2012, 2013

...Administration [TA-W-72,471] The Walker Auto Group, Inc., Miamisburg, OH; Notice...filed on behalf of workers at The Walker Auto Group, Inc., Miamisburg, Ohio, was...be eligible for TAA because the Walker Auto Group, Inc., Miamisburg, Ohio,...

2010-05-05

74

Baby walker associated scalding injuries seen at University Hospital Kuala Lumpur.  

PubMed

Baby walker associated injuries are occurring in Malaysia. Most are not noticed as paediatricians are more concerned with the treatment of the injury and forget the preventive measures required to overcome this problem. We believe that baby walkers should be banned in Malaysia as the risks of injury far outweighs any benefits. We present 4 cases of baby walker associated scalding injuries. PMID:7565196

Sendut, I H; Tan, K K; Rivara, F

1995-06-01

75

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.

76

User directional intention recognition of an omnidirectional walking support walker  

Microsoft Academic Search

An omnidirectional walking support walker (ODW) is being developed. In order to provide walking support according to the user directional intention, we propose a method to recognize the user directional intention from forearm pressures. The pressures between forearms and the ODW are measured by 4 force sensors embedded in the ODW's armrest. The relationship between forearm pressure and user directional

Yinlai Jiang; Kenji Ishida; Shuoyu Wang; Takeshi Ando; Masakatsu G. Fujie

2011-01-01

77

Controlling the Walking Period of a Pneumatic Muscle Walker  

Microsoft Academic Search

In this paper, we investigate the limit cycle of a biped walker driven by pairs of pneumatic artificial muscles. We show, experimentally, that the period of the limit cycle changes when we apply different control parameters and we estimate the relationship between the period and the parameters through trials. A step-by-step feedback controller is proposed to stabilize walking based on

Takashi Takuma; Koh Hosoda

2006-01-01

78

Actuating a Simple 3D Passive Dynamic Walker  

Microsoft Academic Search

The passive dynamic walker described in this paper is a robot with a minimal number of degrees of freedom which is still capable of stable 3D dynamic walking. First, we present the reduced-order dynamic models used to tune the characteristics of the robot's passive gait. Our sagittal plane model is closely related to the compass gait model, but the steady

Russ Tedrake; Teresa Weirui Zhang; Ming-fai Fong; H. Sebastian Seung

2004-01-01

79

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

80

Psychosis and Dandy–Walker complex: report of four cases  

Microsoft Academic Search

Concurrence of psychosis and Dandy–Walker complex (DWC) has been reported in some medical literature. Here, we reported four patients with concurrent psychosis and DWC of all four subtypes. Some clinical features found were juvenile or young adult age onset, high frequency of family history of psychosis, atypical psychotic symptoms, and high prevalence of cognitive deficit and refractoriness to treatment, in

Zhaoyu Gan; Feici Diao; Zili Han; Kanglai Li; Liarong Zheng; Nianhong Guan; Zhuang Kang; Xiaoli Wu; Qinling Wei; Minfeng Cheng; Ming Zhang; Jinbei Zhang

81

Directional Intention Identification for Running Control of an Omnidirectional Walker  

Microsoft Academic Search

Walking is a vital exercise for health promotion and a fundamental ability necessary for everyday life. In the authors' previous studies, an omni-directional walker (ODW) has been developed for walking rehabilitation and walking support. In the case of walking support, it is necessary for the ODW to know which direction its user is intending to go according to the user's

Yinlai Jiang; Shuoyu Wang; Kenji Ishida; Takeshi Ando; Masakatsu G. Fujie

2010-01-01

82

The Teller and the Tale: Walker Percy's Lancelot as Metafiction  

Microsoft Academic Search

Walker Percy is not usually thought of as a writer of experimental fiction, although early in his career he hinted at a direction for his work that would take him away from traditional realism. He said in 1963, “[…] there is a disintegration of the fabric of the modern world which is so far advanced that the conventional novel no

Michael Kobre

1999-01-01

83

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

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

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

84

3. GENERAL VIEW LOOKING NORTH FROM THE INTERSECTION OF WALKER ...  

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

3. GENERAL VIEW LOOKING NORTH FROM THE INTERSECTION OF WALKER AND LUMBER STREETS, SHOWING TWO HOUSES FRONTING ON LUMBER STREET, AND CENTRAL OF GEORGIA COACH AND PAINT SHOP IN BACKGROUND AT END OF STREET - Frogtown District, Bounded by Jones, I-66 Ramp, & West Boundary Streets, Savannah, Chatham County, GA

85

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.

86

Non-motorized vehicles and walkers: going for “broke”  

Microsoft Academic Search

Many emergency department visits are for trauma resulting from mishaps while using wheeled sports equipment. While these injuries among children and adolescents are common, much of the variation in injury frequency and severity depends on the age of the child and protective equipment used. This article will discuss injuries related to baby walkers as well as various wheeled sporting equipment,

Elizabeth C Powell

2003-01-01

87

ISS Update: Astronaut Shannon Walker – 07.17.2012  

NASA Video Gallery

In the International Space Station flight control room at NASA’s Johnson Space Center, Houston, ISS Update commentator Amiko Kauderer interviewed Shannon Walker, NASA astronaut and Expedition 24 and 25 flight engineer. Questions? Ask us on Twitter @NASA_Johnson and include the hashtag #askStation. For the latest news about the space station, visit http://www.nasa.gov/station.

Russell Todd D

2012-07-17

88

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

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

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

91

A new species of Culcua Walker (Diptera: Stratiomyidae) from Vietnam  

Technology Transfer Automated Retrieval System (TEKTRAN)

A new species of Culcua Walker (Diptera: Stratiomyidae), C. lingafelteri Woodley, new species, is described from northern Vietnam. It is diagnosed relative to other species using the recent revision of the genus by Rozkošný and Kozánek (2007). This is the first species of Culcua reported from Viet...

92

Creation of Particles in a Robertson-Walker Universe.  

National Technical Information Service (NTIS)

The purpose of this paper is to study the pair-creation of particles in any Robertson-Walker universe specified by some metric. A massive scaler field and its conjugate momentum can be quantized. Then the commutation relation is imposed on them. The topol...

H. Nariai

1978-01-01

93

Rehabilitation walker system for standing-up motion  

Microsoft Academic Search

This paper proposes a walker system with power assistance device for standing up motion. Our system focuses on family use for aged person who needs nursing in their daily life. Our key ideas are two topics. The first topic is new assistance manipulator mechanism with four parallel linkages. Our proposed manipulator mechanism requires only smaller actuators and realizes rigid structure

Daisuke Chugo; Wataru Matsuoka; Songmin Jia; Kunikatsu Takase

2007-01-01

94

Emplacement of Basaltic Lava Flows: the Legacy of GPL Walker  

Microsoft Academic Search

Through his early field measurements of lava flow morphology, G.P.L. Walker established a framework for examination of the dynamics of lava flow emplacement that is still in place today. I will examine this legacy as established by three early papers: (1) his 1967 paper, where he defined a relationship between the thickness of recent Etna lava flows and the slope

K. V. Cashman

2005-01-01

95

Reduced Incidence of Cardiac Arrhythmias in Walkers and Runners  

PubMed Central

Purpose Walking is purported to reduce the risk of atrial fibrillation by 48%, whereas jogging is purported to increase its risk by 53%, suggesting a strong anti-arrhythmic benefit of walking over running. The purpose of these analyses is to compare incident self-reported physician-diagnosed cardiac arrhythmia to baseline energy expenditure (metabolic equivalent hours per day, METhr/d) from walking, running and other exercise. Methods Proportional hazards analysis of 14,734 walkers and 32,073 runners. Results There were 1,060 incident cardiac arrhythmias (412 walkers, 648 runners) during 6.2 years of follow-up. The risk for incident cardiac arrhythmias declined 4.4% per baseline METhr/d walked by the walkers, or running in the runners (P?=?0.0001). Specifically, the risk declined 14.2% (hazard ratio: 0.858) for 1.8 to 3.6 METhr/d, 26.5% for 3.6 to 5.4 METhr/d, and 31.7% for ?5.4 METhr/d, relative to <1.8 METhr/d. The risk reduction per METhr/d was significantly greater for walking than running (P<0.01), but only because walkers were at 34% greater risk than runners who fell below contemporary physical activity guideline recommendations; otherwise the walkers and runners had similar risks for cardiac arrhythmias. Cardiac arrhythmias were unrelated to walking and running intensity, and unrelated to marathon participation and performance. Conclusions The risk for cardiac arrhythmias was similar in walkers and runners who expended comparable METhr/d during structured exercise. We found no significant risk increase for self-reported cardiac arrhythmias associated with running distance, exercise intensity, or marathon participation. Rhythm abnormalities were based on self-report, precluding definitive categorization of the nature of the rhythm disturbance. However, even if the runners’ arrhythmias include sinus bradycardia due to running itself, there was no increase in arrhythmias with greater running distance.

Williams, Paul T.; Franklin, Barry A.

2013-01-01

96

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

PubMed Central

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

DiLillo, D; Damashek, A; Peterson, L

2001-01-01

97

Dandy-Walker syndrome studied by computed tomography and pneumoencephalography  

SciTech Connect

Based on air studies, some authors have disputed the ability of computed tomography (CT) to diagnose posterior fossa cysts. The authors correlated the pneumoencephalographic, CT, and pathological findings in 4 patients with classic Dandy-Walker syndrome. Three cases had been misdiagnosed as retrocerebellar arachnoid cysts because the fourth ventricle was incorrectly considered normal on brow-up or erect air studies, reflecting the inability of such studies to evaluate an agenetic vermis and deficient posterior medullary velum which are characteristic of Dandy-Walker malformation. Careful correlation with autopsy findings showed that even with complete agenesis of the inferior vermis, if the slit between the cerebellar hemispheres is narrow, the fourth ventricle could be misinterpreted as normal on pneumoencephalography and sagittal CT. Radionuclide studies, a small amount of air, or metrizamide may be needed to determine whether the cyst communicates with the subarachnoid space.

Masdeu, J.C. (Hines Veterans Administration Hospital, Maywood, IL); Dobben, G.D.; Azar-Kia, B.

1983-04-01

98

Last Glacial Maximum's effect on the Walker circulation  

NASA Astrophysics Data System (ADS)

Over the tropical Pacific Ocean the Walker circulation is an atmospheric flow pattern that runs parallel to the equator, with ascending motion over the western Pacific and a horizontal tropospheric return flow that carries air back to the east. Scientists predict that the Walker circulation will weaken with global warming through a mechanism known as the Held, Soden, and Vecchi (HSV) mechanism. According to this system, as surface ocean temperatures increase, atmospheric humidity and precipitation rates will also increase. Conversely, as surface ocean temperatures decrease, atmospheric humidity and local precipitation will decrease. Humidity levels change much more easily than precipitation rates; as temperatures rise, this disparity leads to a decrease in vertical air motion as the atmosphere tries to maintain a balanced flow of air. If temperatures fall, vertical air motion will increase. Although the HSV mechanism is a robust feature of climate models, its observed sensitivity to changing temperatures remains uncertain.

Schultz, Colin

2011-10-01

99

Chiral Potts Models, Friendly Walkers and Directed Percolation Problem  

Microsoft Academic Search

The lambda-state chiral Potts model on a finite directed latticeis defined, whose partition function under a certain boundarycondition becomes the directed percolation (DP)probability for a finite lattice in the lambda-->1 limit.We also introduce the system of m friendly walkers of Ltime-steps and prove that its generating functionof trajectories is equal to the partition function of the lambda-state chiral Potts model

Tomoko Tsuchiya; Makoto Katori

1998-01-01

100

Local blood flow in Walker 256 metastatic brain tumors  

Microsoft Academic Search

Local blood flow (F) in metastatic Walker 256 (WL-256) brain tumors produced by the intracarotid artery injection of WL-256 tumor cells in rats was measured using 14C-odoantipyrine and quantitative autoradiography. Blood flow was variable in the tumors; the overall range was 2 to 222 ml hg-1 min-1 and the maximum range in an individual tumor extended over 150 ml hg-1

Ronald G Blasberg; William R Shapiro; Peter Molnar; Clifford S Patlak; Joseph D Fenstermacher

1984-01-01

101

Dandy-Walker malformation: analysis of 38 cases  

Microsoft Academic Search

Thirty-eight cases of Dandy-Walker malformation (DWM) are presented. A female predominance of 3:1 was found. Thirty-two cases (84%) were diagnosed within the 1st year of life. Of these, 17 cases (44.7%) were diagnosed at birth. Ten (26%) were delivered by cesarean section. Thirteen infants (34%) had a birth weight below 3000 g. Several associated malformations were observed, the most frequent

I. Pascual-Castroviejo; A. Velez; S. I. Pascual-Pascual; M. C. Roche; F. Villarejo

1991-01-01

102

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

103

Friedman—Robertson—Walker Models with Late-Time Acceleration  

NASA Astrophysics Data System (ADS)

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

Abdussattar; Prajapati, S. R.

2011-02-01

104

Baby walkers--still a major cause of infant burns.  

PubMed

Baby walkers have been implicated in many forms of paediatric trauma, ranging from finger tip entrapment to severe head injury. Their relationship to childhood burns has been documented previously. The Department of Trade and Industry published further warnings in 1984 and the British Standards Institution in 1989. We wished to determine if the degree or frequency of thermal injury had been lessened by these recommendations. All parents of children under 15 months of age admitted to this unit in 1994 were asked if their child was in a baby walker at the time of injury. Eight of the 32 infants, aged between 6 and 12 months, were burned in their walking aid. Half of the burns were contact and half scalds, and the average in-patient stay was 8 days. One patient required formal resuscitation and three were grafted. The incidence and severity of thermal injury sustained in baby walkers remains at a high level despite increased safety measures. Perhaps it is time to concur with the American Academy of Paediatrics and recommend a ban on these dangerous aids. PMID:9426918

Cassell, O C; Hubble, M; Milling, M A; Dickson, W A

1997-08-01

105

Stability Margin Monitoring in Steering-Controlled Intelligent Walkers for the Elderly  

Microsoft Academic Search

This paper emphasizes the importance of assessing stability index for steering-controlled three-wheeled walkers. The paper describes a stability computation model that can be used to generate a reference input to the intelligent shared- control algorithm. The model can be used to evaluate the instantaneous stability margin of the walker-user system. This knowledge of the online stability of the walker will

Majd Alwan; Prabhu Jude Rajendran; Alexandre Ledoux; Cunjun Huang; Glenn Wasson; Pradip Sheth

106

Anisotropic evolution of 5D Friedmann-Robertson-Walker spacetime  

SciTech Connect

We examine the time evolution of the five-dimensional Einstein field equations subjected to a flat, anisotropic Robertson-Walker metric, where the 3D and higher-dimensional scale factors are allowed to dynamically evolve at different rates. By adopting equations of state relating the 3D and higher-dimensional pressures to the density, we obtain an exact expression relating the higher-dimensional scale factor to a function of the 3D scale factor. This relation allows us to write the Friedmann-Robertson-Walker field equations exclusively in terms of the 3D scale factor, thus yielding a set of 4D effective Friedmann-Robertson-Walker field equations. We examine the effective field equations in the general case and obtain an exact expression relating a function of the 3D scale factor to the time. This expression involves a hypergeometric function and cannot, in general, be inverted to yield an analytical expression for the 3D scale factor as a function of time. When the hypergeometric function is expanded for small and large arguments, we obtain a generalized treatment of the dynamical compactification scenario of Mohammedi [Phys. Rev. D 65, 104018 (2002)] and the 5D vacuum solution of Chodos and Detweiler [Phys. Rev. D 21, 2167 (1980)], respectively. By expanding the hypergeometric function near a branch point, we obtain the perturbative solution for the 3D scale factor in the small time regime. This solution exhibits accelerated expansion, which, remarkably, is independent of the value of the 4D equation of state parameter w. This early-time epoch of accelerated expansion arises naturally out of the anisotropic evolution of 5D spacetime when the pressure in the extra dimension is negative and offers a possible alternative to scalar field inflationary theory.

Middleton, Chad A. [Department of Physical and Environmental Sciences, Colorado Mesa University (formerly Mesa State College), Grand Junction, Colorado 81501 (United States); Stanley, Ethan [Department of Physics, Purdue University, West Lafayette, Indiana 47907 (United States)

2011-10-15

107

Promoting child safety in primary care: a cluster randomised controlled trial to reduce baby walker use  

PubMed Central

Background Baby walkers are commonly used items of nursery equipment, but cause more than 3000 injuries each year in the UK. There is currently little evidence regarding the effectiveness of interventions in primary care to reduce walker use. Aim To evaluate the effectiveness of an educational package provided by midwives and health visitors to reduce baby walker possession and use. Design of study Cluster randomised controlled trial. Setting Sixty-four general practices in Nottingham and North Nottinghamshire, UK. Method An educational package aimed at discouraging mothers-to-be from obtaining and using a walker was delivered by midwives and health visitors to 1174 mothers-to-be of at least 28 weeks gestation. The control arm received usual care. Primary outcome measures were the possession and use of a walker. Secondary outcome measures included the frequency and duration of walker use, knowledge and attitudes towards walkers, plans to use a walker with future children, recommending a walker to a friend, and use of stair gates and fire guards. Results Intervention arm participants were significantly less likely to own (odds ratio [OR] = 0.63, 95% confidence interval [CI] = 0.43 to 0.93) or to use a walker (OR = 0.26, 95% CI = 0.08 to 0.84). They were significantly less likely to plan to use a walker with their next child (OR = 0.52, 95% CI = 0.31 to 0.86) or to agree that walkers keep children safe (OR = 0.35, 95% CI = 0.16 to 0.78). There was some evidence that they were less likely to recommend a walker to a friend (OR = 0.51, 95% CI = 0.28 to 0.91) or to agree that they help children to walk more quickly (OR = 0.53, 95% CI = 0.29 to 0.95). Conclusion An educational package delivered by midwives and health visitors was effective in reducing baby walker possession and use. Providers of primary healthcare services should include baby walker education in their injury prevention strategy and child health promotion programme.

Kendrick, Denise; Illingworth, Rachel; Woods, Amanda; Watts, Kim; Collier, Jacqueline; Dewey, Michael; Hapgood, Rhydian; Chen, Chih-Mei

2005-01-01

108

Dynamics of a scalar field in Robertson-Walker spacetimes  

SciTech Connect

We analyze the dynamics of a single scalar field in Friedmann-Robertson-Walker universes with spatial curvature. We obtain the fixed point solutions which are shown to be late time attractors. In particular, we determine the corresponding scalar field potentials which correspond to these stable solutions. The analysis is quite general and incorporates expanding and contracting universes with both positive and negative scalar potentials. We demonstrate that the known power law, exponential, and de Sitter solutions are certain limits of our general set of solutions.

Copeland, Edmund J.; Shaeri, Maryam [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Mizuno, Shuntaro [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Research Center for the Early Universe (RESCEU), School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan)

2009-05-15

109

The enigmatic young object: Walker 90/V590 Monocerotis  

NASA Astrophysics Data System (ADS)

Aims: We assess the evolutionary status of the intriguing object Walker 90/V590 Mon, which is located about 20 arcmin 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 mag 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 H? emission, Mg II emission, IR excess, UV continuum, and optical variability. Methods: 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. Results: 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 (overline{12.47} ± 0.06). 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 VISIR images secured in 2004, Walker 90 appears as a point source placing an upper limit of < 0.1 arcsec for its diameter. Evidence of turbulent inflows is found in rapidly changing inverse P-Cygni profiles in the lower Balmer lines, with a broadening of ±400 km s-1 in H? and a redshifted component in H? with a terminal velocity of 600 km s-1. The measured steep UV continuum fluxes (mimicking a star as early as B4), added to a tentative identification of N V emission, suggest a strong non-photospheric component, typically of fluxes arising from a thermally inhomogeneous accretion disk. We detect a well defined 2200 Å bump, indicative of dense material in the line-of-sight. We conclude that many observational features are explained if W90 is a flared disk system, surrounded by an inclined optically thick accretion disk. Based on observations made with ESO Telescopes at Paranal Observatory under programme ID 075.C-0528(A). Tables 1-5 are only available in electronic form at http:/www.aanda.org

Pérez, M. R.; McCollum, B.; van den Ancker, M. E.; Joner, M. D.

2008-08-01

110

Evapotranspiration from the Lower Walker River Basin, West-Central Nevada, Water Years 2005-07  

USGS Publications Warehouse

Evapotranspiration is the ultimate path of outflow of nearly all water from the Lower Walker River basin. Walker Lake is the terminus of the topographically closed Walker River basin, and the lake level has been declining at an average rate of about 1.6 feet per year (ft/yr) since 1917. As a result of the declining lake level, dissolved-solids concentrations are increasingly threatening the fishery and ecosystem health of the lake. Uncertainties in the water budget components of the Lower Walker River basin led the U.S. Geological Survey, in cooperation with the Bureau of Reclamation, to undertake an investigation to refine estimates of the water budget. Evapotranspiration from the Lower Walker River basin represents a major component of this water budget. The specific objectives of this report are to provide estimates of total and net evapotranspiration for water years 2005-07 for areas in the Lower Walker River basin in which annual evapotranspiration exceeds annual precipitation, and to summarize these results for areas of similar vegetation and soil characteristics, hydrographic subareas, and Walker Lake and Weber Reservoir. The three hydrographic subareas include the area along Walker River north of Walker Lake, the area of and adjacent to Walker Lake, and the area south of Walker Lake. Areas of annual evapotranspiration exceeding annual precipitation were identified and mapped in the field and were further delineated using remote-sensing analysis. These areas were classified into 10 evapotranspiration units. A network of 11 evapotranspiration stations was operated in natural and agricultural vegetation and on Walker Lake. Measured evapotranspiration rates ranged from 0.5 ft/yr at a sparsely vegetated desert shrub site to 5.0 ft/yr from Walker Lake. The greatest evapotranspiration rate on land was 4.1 ft/yr at an irrigated alfalfa field, and the greatest rate for natural vegetation was 3.9 ft/yr in a riparian community along Walker River. At an evapotranspiration station in a saltcedar grove, measurements indicated a possible decrease in evapotranspiration of about 50 percent due to defoliation of the saltcedar by the saltcedar leaf beetle. Total evapotranspiration from the evapotranspiration units identified in the Lower Walker River basin was about 231,000 acre-feet per year (acre-ft/yr). Of this amount, about 45,000 acre-ft/yr originated from direct precipitation, resulting in net evapotranspiration of about 186,000 acre-ft/yr. More than 80 percent of net evapotranspiration in the Lower Walker River basin was through evaporation from Walker Lake. Total evaporation from Walker Lake was about 161,000 acre-ft/yr and net evaporation was about 149,000 acre-ft/yr. Some previous estimates of evaporation from Walker Lake based on water-budget analysis actually represent total evaporation minus ground-water inflow to the lake. Historical evaporation rates determined on the basis of water budget analysis were less than the evaporation rate measured directly during this study. The difference could represent ground-water inflow to Walker Lake of 16,000 to 26,000 acre-ft/yr or could indicate that ground-water inflow to Walker Lake is decreasing over time as the lake perimeter recedes.

Allander, Kip K.; Smith, J. LaRue; Johnson, Michael J.

2009-01-01

111

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

112

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

113

Walking Speed of Older Pedestrians Who Use Canes or Walkers for Mobility  

Microsoft Academic Search

Findings are presented of a follow-up study conducted in Winnipeg, Canada, to investigate the walking speed of older pedestrians who use walkers or canes for mobility. The results are from research conducted to understand the differences between the normal and the crossing walking speeds of older pedestrians who use walkers or canes for mobility at signalized intersections. This walking speed

Jorge Arango; Jeannette Montufar

2008-01-01

114

Reclamation in Walker's Jubilee: The Context of Development of the Historical Novel  

Microsoft Academic Search

This article attempts to contribute to the scholarship on Margaret Walker's Jubilee, ancestor of a wave of neo-enslaved narratives and African-American historical fictions, by shedding more light on the context of its development. While most critics implicitly tie the development of Walker's historical novel to the sixties, the text is a product of the thirties which gave impetus to the

Babacar Dieng; Berger de Saint-Louis

2008-01-01

115

Hydrologic Setting and Conceptual Hydrologic Model of the Walker River Basin, West-Cental Nevada.  

National Technical Information Service (NTIS)

The Walker River is the main source of inflow to Walker Lake, a closed-basin lake in west-central Nevada. Between 1882 and 2008, agricultural diversions resulted in a lake-level decline of more than 150 feet and storage loss of 7,400,000 acre-ft. Evaporat...

K. K. Allander T. J. Lopes

2009-01-01

116

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

117

Neuroimaging of dandy-walker malformation: new concepts.  

PubMed

Dandy-Walker malformation (DWM) is the most common human cerebellar malformation, characterized by hypoplasia of the cerebellar vermis, cystic dilation of the fourth ventricle, and an enlarged posterior fossa with upward displacement of the lateral sinuses, tentorium, and torcular. Although its pathogenesis is not completely understood, there are several genetic loci related to DWM as well as syndromic malformations and congenital infections. Dandy-Walker malformation is associated with other central nervous system abnormalities, including dysgenesis of corpus callosum, ectopic brain tissue, holoprosencephaly, and neural tube defects. Hydrocephalus plays an important role in the development of symptoms and neurological outcome in patients with DWM, and the aim of surgical treatment is usually the control of hydrocephalus and the posterior fossa cyst. Imaging modalities, especially magnetic resonance imaging, are crucial for the diagnosis of DWM and distinguishing this disorder from other cystic posterior fossa lesions. Persistent Blake's cyst is seen as a retrocerebellar fluid collection with cerebrospinal fluid signal intensity and a median line communication with the fourth ventricle, commonly associated with hydrocephalus. Mega cisterna magna presents as an extraaxial fluid collection posteroinferior to an intact cerebellum. Retrocerebellar arachnoid cysts frequently compress the cerebellar hemispheres and the fourth ventricle. Patients with DWM show an enlarged posterior fossa filled with a cystic structure that communicates freely with the fourth ventricle and hypoplastic vermis. Comprehension of hindbrain embryology is of utmost importance for understanding the cerebellar malformations, including DWM, and other related entities. PMID:24132069

Correa, Gustavo Gumz; Amaral, Lázaro Faria; Vedolin, Leonardo Modesti

2011-12-01

118

Casimir effect for curved boundaries in Robertson-Walker spacetime  

NASA Astrophysics Data System (ADS)

Vacuum expectation values of the energy-momentum tensor and the Casimir forces are evaluated for scalar and electromagnetic fields in the geometry of two curved boundaries on the background of the Robertson-Walker spacetime with negative spatial curvature. The boundaries under consideration are conformal images of the flat boundaries in Rindler spacetime. Robin boundary conditions are imposed in the case of the scalar field and perfect conductor boundary conditions are assumed for the electromagnetic field. We use the conformal relation between the Robertson-Walker and Rindler spacetimes and the corresponding results for two parallel plates moving with uniform proper acceleration through the Fulling-Rindler vacuum. For the general scale factor the vacuum energy-momentum tensor is decomposed into the boundary-free and boundary-induced parts. The latter is non-diagonal. The Casimir forces are directed along the normals to the boundaries. For the Dirichlet and Neumann scalars and for the electromagnetic field these forces are attractive for all separations.

Saharian, A. A.; Setare, M. R.

2010-11-01

119

Effects of High Levels of Total Dissolved Solids in Walker Lake, Nevada, on Survival and Growth of Lahontan Cutthroat Trout  

Microsoft Academic Search

Walker Lake, Nevada, is an endorheic terminal lake experiencing significant increases in total dissolved solids (TDS) because of culturally derived reductions in inflow and continued evaporative water losses. Maintenance of the Walker Lake fishery for native Lahontan cutthroat trout Oncorhynchus clarki henshawi requires artificial propagation because fish no longer have access to suitable spawning sites upstream in the Walker River.

Bobette R. Dickerson; Gary L. Vinyard

1999-01-01

120

Impact of strut height on offloading capacity of removable cast walkers  

PubMed Central

Background Reducing weight-bearing stress to diabetic foot ulcers is critical to healing and commonly called offloading. Removable cast walkers are frequently used for offloading; however, patient compliance is often poor. Walkers commonly extend to the knee. Patients complain about walkers' weight and diminished balance with their use. This study compared the offloading capacity of walkers that varied by height. Heights included: knee, ankle, and shoe levels. To ensure a fair comparison the outsole and insole were standardized across the devices. Methods Eleven diabetic subjects with moderate to high risk of ulceration were recruited. Subjects completed four 20 m walking trials. Subjects performed one trial with each walker and one trial with an athletic shoe. Primary outcomes focused on plantar loading and were measured by pressure insoles. Secondary outcomes were associated with gait kinematics as collected by body worn sensors. Findings Significant differences were found for the peak pressure and pressure time integrals of the different footwear. All walkers performed better than the athletic shoe. The ankle and knee-high devices performed best. Center of mass rotation data showed a trend of the ankle walker yielding a smaller range of motion (18% medial/lateral and 22% anterior/posterior) than the knee level. Interpretation The ankle-high walker was able to provide similar offloading capacities as the knee-high walker. The diminished weight, along with potentially improved stability, may result in improved compliance with ankle-high walkers. A study comparing the use of the two devices for treating ulcers is now suggested.

Crews, Ryan T.; Sayeed, Fraaz; Najafi, Bijan

2013-01-01

121

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

122

Improved solubility of replication factor C (RFC) Walker A mutants  

PubMed Central

Protein insolubility often poses a significant problem during purification protocols and in enzyme assays, especially for eukaryotic proteins expressed in a recombinant bacterial system. The limited solubility of replication factor C (RFC), the clamp loader complex from Saccharomyces cerevisiae, has been previously documented. We found that mutant forms of RFC harboring a single point mutation in the Walker A motif were even less soluble than the wild-type complex. The addition of maltose at 0.75 M to the storage and assay buffers greatly increases protein solubility and prevents the complex from falling apart. Our analysis of the clamp loading reaction is dependent on fluorescence-based assays, which are environmentally sensitive. Using wt RFC as a control, we show that the addition of maltose to the reaction buffers does not affect fluorophore responses in the assays or the enzyme activity, indicating that maltose can be used as a buffer additive for further downstream analysis of these mutants.

Marzahn, Melissa R.; Bloom, Linda B.

2013-01-01

123

Clustering Determines Who Survives for Competing Brownian and Lévy Walkers  

NASA Astrophysics Data System (ADS)

The competition between two ecologically similar species that use the same resources and differ from each other only in the type of spatial motion they undergo is studied. The latter is assumed to be described either by Brownian motion or Lévy flights. Competition is taken into account by assuming that individuals reproduce in a density-dependent fashion. It is observed that no influence of the type of motion occurs when the two species are in a well-mixed unstructured state. However, as soon as the species develop spatial clustering, the one forming more concentrated clusters gets a competitive advantage and eliminates the other. A similar competitive advantage would occur between walkers of the same type but with different diffusivities if this leads also to different clustering. The coexistence of both species is also possible under certain conditions.

Heinsalu, Els; Hernández-Garcia, Emilio; López, Cristóbal

2013-06-01

124

Complete mitochondrial genome of Chilo suppressalis (Walker) (Lepidoptera: Crambidae).  

PubMed

The complete sequence of the mitochondrial genome (mitogenome) of the rice stem borer Chilo suppressalis (Walker) (Lepidoptera: Crambidae) was determined to be 15,465 bp. It contains 13 protein-coding genes (PCGs), 22 tRNA genes, the large and small rRNA genes, and an A+T-rich region. The nucleotide composition of the mitogenome of C. suppressalis is highly A+T biased, accounting for 79.70% in whole mitogenome, 77.74% in PCGs, 84.70% in tRNAs, 81.20% in rRNAs and 94.19% in A+T-rich region, respectively. The PCGs have typical ATN start codons, except for cox1, which contains the unusual CGA. The C. suppressalis A+T-rich region contains a conserved structure combining the motif ATAGA and a 19-bp poly-T stretch, but absence of the 9-bp poly-A element upstream trnM. PMID:21864029

Yin, Jiao; Wang, Ai-Min; Hong, Gui-Yun; Cao, Ya-Zhong; Wei, Zhao-Jun

2011-06-01

125

Walker-Warburg syndrome. Report of two cases.  

PubMed

The purpose of this study is to describe two infants that were diagnosed with Walker-Warburg syndrome (WWS), a rare form of congenital muscular dystrophy (CMD). They were studied in their clinical, laboratory, and neuroradiologic features. The index case had a brain magnetic resonance imaging (MRI) and the second patient had a head computerized tomography (CT). In addition, a literature review was performed to describe the main forms of CMD. The index case fulfilled all criteria for WWS. A brain MRI performed at age 4 months served to corroborate the clinical diagnosis, showing severe hydrocephalus, type II lissencephaly, cerebellar vermian aplasia, and a hypoplastic brain stem. The authors were able to establish a retrospective diagnosis of WWS in the index case's older sister, based upon her clinical picture and head CT report. PMID:10667295

Vasconcelos, M M; Guedes, C R; Domingues, R C; Vianna, R N; Sotero, M; Vieira, M M

1999-09-01

126

Assistive devices alter gait patterns in Parkinson disease: advantages of the four-wheeled walker.  

PubMed

Gait abnormalities are a hallmark of Parkinson's disease (PD) and contribute to fall risk. Therapy and exercise are often encouraged to increase mobility and decrease falls. As disease symptoms progress, assistive devices are often prescribed. There are no guidelines for choosing appropriate ambulatory devices. This unique study systematically examined the impact of a broad range of assistive devices on gait measures during walking in both a straight path and around obstacles in individuals with PD. Quantitative gait measures, including velocity, stride length, percent swing and double support time, and coefficients of variation were assessed in 27 individuals with PD with or without one of six different devices including canes, standard and wheeled walkers (two, four or U-Step). Data were collected using the GAITRite and on a figure-of-eight course. All devices, with the exception of four-wheeled and U-Step walkers significantly decreased gait velocity. The four-wheeled walker resulted in less variability in gait measures and had less impact on spontaneous unassisted gait patterns. The U-Step walker exhibited the highest variability across all parameters followed by the two-wheeled and standard walkers. Higher variability has been correlated with increased falls. Though subjects performed better on a figure-of-eight course using either the four-wheeled or the U-Step walker, the four-wheeled walker resulted in the most consistent improvement in overall gait variables. Laser light use on a U-Step walker did not improve gait measures or safety in figure-of-eight compared to other devices. Of the devices tested, the four-wheeled-walker offered the most consistent advantages for improving mobility and safety. PMID:23237981

Kegelmeyer, Deb A; Parthasarathy, Sowmya; Kostyk, Sandra K; White, Susan E; Kloos, Anne D

2012-12-11

127

Four-wheeled walker related injuries in older adults in the Netherlands.  

PubMed

BACKGROUND: With ageing populations worldwide, mobility devices are used more than ever. In the current literature there is no consensus whether the available mobility devices safely improve the mobility of their users. Also, evidence is lacking concerning the risks and types of injuries sustained while using a four-wheeled walker. OBJECTIVE: To assess injury risks and injury patterns in older adults (?65 years) who presented at Emergency Departments (ED) in the Netherlands with an injury due to using a four-wheeled walker. DESIGN AND SETTING: In this study, the Dutch Injury Surveillance System was used to obtain a national representative sample of annual ED visits in the Netherlands in the adult population (?65 years) sustaining an injury while using a four-wheeled walker. The numbers of four-wheeled walker users in the Netherlands were obtained from the national insurance board. The numbers of ED visits were divided by the numbers of four-wheeled walker users to calculate age- and sex-specific injury risks. RESULTS: Annually 1869 older adults visited an ED after sustaining an injury while using a four-wheeled walker. Falls were the main cause of injury (96%). The injury risk was 3.1 per 100 users of four-wheeled walkers. Women (3.5 per 100 users) had a higher risk than men (2.0 per 100 users). Injury risk was the highest in women aged 85 years and older (6.2 per 100 users). The majority of injuries were fractures (60%) with hip fracture (25%) being the most common injury. Nearly half of all four-wheeled walker related injuries required hospitalisation, mostly due to hip fractures. Healthcare costs per injury were approximately €12 000. CONCLUSIONS: This study presents evidence that older adults experiencing a fall while using a four-wheeled walker are at high risk to suffer severe injuries. PMID:23592736

van Riel, K M M; Hartholt, K A; Panneman, M J M; Patka, P; van Beeck, E F; van der Cammen, T J M

2013-04-16

128

78 FR 37706 - Safety Standards for Infant Walkers and Infant Swings  

Federal Register 2010, 2011, 2012, 2013

...and 1223 Safety Standards for Infant Walkers and Infant Swings AGENCY...numerous durable infant or toddler products, including infant...standards for durable infant or toddler products. The law requires...term ``durable infant or toddler product'' explicitly...

2013-06-24

129

50. OVERALL VIEW OF LOWER MAIN STREET, WITH M.M. WALKER ...  

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

50. OVERALL VIEW OF LOWER MAIN STREET, WITH M.M. WALKER COMPANY WAREHOUSE IN LEFT FOREGROUND AND THOMAS J. MULGREW COMPANY BUILDING IN RIGHT BACKGROUND. VIEW TO SOUTHEAST. - Dubuque Commercial & Industrial Buildings, Dubuque, Dubuque County, IA

130

Walker Branch Throughfall Displacement Experiment Data Report: Site Characterization, System Performance, Weather, Species, Composition, and Growth.  

National Technical Information Service (NTIS)

This numeric data package provides data sets, and accompanying documentation, on site characterization, system performance, weather, species composition, and growth for the Throughfall Displacement Experiment, which was established in the Walker Branch Wa...

P. J. Hanson

2001-01-01

131

Maggie Lena Walker Story (Closed Captioned) (VHS 1/2 inch) (Video).  

National Technical Information Service (NTIS)

The video details the life and accomplishments of America's first woman banker. Maggie Walker was an inspirational leader of the black community, a financier, newspaper publisher and leader of a successful organization. It is hoped that this video will in...

1991-01-01

132

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

2007-06-25

133

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

134

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

135

Does the Universe expand? Cosmological spectral shift and interpretation of Robertson-Walker spacetime  

Microsoft Academic Search

The cosmological spectral shift is a change of the cosmic frequency of a photon along its trajectory and is connected with no specific interpretation of the Robertson-Walker spacetime. Parallel with the generally accepted \\

V. S. Mashkevich

1993-01-01

136

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

Microsoft Academic Search

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

Terumasa Narukawa; Kazuto Yokoyama; Masaki Takahashi; Kazuo Yoshida

2008-01-01

137

Lipid in pancreatic exocrine cells of rats bearing the Walker tumour.  

PubMed

Exocrine cells of the pancreas of male rats bearing the Walker carcinoma show a striking accumulation of stainable neutral lipid in the form of small aggregated droplets in the base of the cells. In several cases, epithelial cells of small ducts also contained fat. Stainable lipid is sometimes present in cells of the pancreas of normal rats and in rats in which the Walker tumour has failed to grow: lipid in duct cells was confined to tumour-bearing animals. PMID:4114814

Parry, E W

1972-06-01

138

The conformal group SO(4,2) and Robertson-Walker spacetimes  

Microsoft Academic Search

The Robertson-Walker spacetimes are conformally flat and so are conformally invariant under the action of the Lie group SO (4,2), the conformal group of Minkowski spacetime. We find a local coordinate transformation allowing the Robertson-Walker metric to be written in a manifestly conformally flat form for all values of the curvature parameter k continuously and use this to obtain the

Aidan J. Keane; Richard K. Barrett

2000-01-01

139

Stratigraphic significance and provenance of the Ordovician Walker Mountain Sandstone Member, Virginia and Tennessee  

SciTech Connect

The Ordovician (Mohawkian) Walker Mountain Sandstone Member of the Bays, Moccasin, and Eggleston Formations is a thin ([approx] 1--15 meters), widespread, conglomeratic sheet sand deposit in the Valley and ridge Province of Virginia and Tennessee. Recent work by the authors has shown that the Walker Mountain is laterally persistent across major regional facies changes, and marks an unconformity of regional extent in nearly all areas of occurrence. The basal bed of the Walker Mountain is commonly a conglomeratic quartz arenite, and is the most distinctive and recognizable bed of the unit. Where the conglomeratic basal bed is absent, the Walker Mountain consists either of a fine- to medium-grained, mature quartz arenite (southern sections) or a fine- to medium-grained quartz and sublithic arenite with appreciable clay matrix (northern sections). Petrologically, the basal conglomeratic bed of the Walker Mountain is compositionally very mature and in most areas has a bimodal texture; grains of the larger mode are extremely well rounded, and those of the smaller mode are subrounded to subangular. Preliminary field observations and petrographic analysis suggest that Walker Mountain sediments were derived from highlands to the present-day east, probably an accretionary wedge composed mostly of older Paleozoic passive margin sediments, and lesser plutonic igneous and low-grade metamorphic rocks.

Goggin, K.E. (Univ. of Georgia, Athens, GA (United States). Dept. of Geology); Haynes, J.T. (Smithsonian Inst., Washington, DC (United States). Dept. of Mineral Sciences)

1994-03-01

140

A new Walker with upper trunk suspension system for severely disabled patients.  

PubMed

We have recently designed a new type of walker for those severely disabled patients who cannot walk with commonly used medical walkers. A drawing and the description of this new walker is reported in order to permit the worldwide companies as well as artisans to develop and produce it for the people affected from severe motor problems. This walker supposes the patient wearing either a modified climbing harness or equipped clothes and being suspended to the walking frame. It consists in two series of bands suspending the patient from the frame; the upper one suspends him for the upper part of his trunk, the lower one by his pelvis. This walker is suggested for patients belonging to three principal groups: (1) Persons who have no trunk control (e.g.: patients affected by severe stroke or ataxias). (2) Persons whose walk is allowed only if they achieve a significant reduction (up to 30-40%) of the their body weight charging on trunk, spine, and lower limbs. (3) Persons who need a differentiated reduction of the body weight either among anterior and posterior side or among their right and left part of the body (hemiparesis, Parkinson disease, scoliosis, kyphosis). Creating this walker is easy; producing costs are low; there are no maintenance costs. PMID:24142620

Scoppetta, C; Scoppetta, M

2013-10-01

141

Hydrologic Setting and Conceptual Hydrologic Model of the Walker River Basin, West-Central Nevada  

USGS Publications Warehouse

The Walker River is the main source of inflow to Walker Lake, a closed-basin lake in west-central Nevada. Between 1882 and 2008, agricultural diversions resulted in a lake-level decline of more than 150 feet and storage loss of 7,400,000 acre-ft. Evaporative concentration increased dissolved solids from 2,500 to 17,000 milligrams per liter. The increase in salinity threatens the survival of the Lahontan cutthroat trout, a native species listed as threatened under the Endangered Species Act. This report describes the hydrologic setting of the Walker River basin and a conceptual hydrologic model of the relations among streams, groundwater, and Walker Lake with emphasis on the lower Walker River basin from Wabuska to Hawthorne, Nevada. The Walker River basin is about 3,950 square miles and straddles the California-Nevada border. Most streamflow originates as snowmelt in the Sierra Nevada. Spring runoff from the Sierra Nevada typically reaches its peak during late May to early June with as much as 2,800 cubic feet per second in the Walker River near Wabuska. Typically, 3 to 4 consecutive years of below average streamflow are followed by 1 or 2 years of average or above average streamflow. Mountain ranges are comprised of consolidated rocks with low hydraulic conductivities, but consolidated rocks transmit water where fractured. Unconsolidated sediments include fluvial deposits along the active channel of the Walker River, valley floors, alluvial slopes, and a playa. Sand and gravel deposited by the Walker River likely are discontinuous strata throughout the valley floor. Thick clay strata likely were deposited in Pleistocene Lake Lahontan and are horizontally continuous, except where strata have been eroded by the Walker River. At Walker Lake, sediments mostly are clay interbedded with alluvial slope, fluvial, and deltaic deposits along the lake margins. Coarse sediments form a multilayered, confined-aquifer system that could extend several miles from the shoreline. Depth to bedrock in the lower Walker River basin ranges from about 900 to 2,000 feet. The average hydraulic conductivity of the alluvial aquifer in the lower Walker River basin is 10-30 feet per day, except where comprised of fluvial sediments. Fluvial sediments along the Walker River have an average hydraulic conductivity of 70 feet per day. Subsurface flow was estimated to be 2,700 acre-feet per year through Double Spring. Subsurface discharge to Walker Lake was estimated to be 4,400 acre-feet per year from the south and 10,400 acre-feet per year from the north. Groundwater levels and groundwater storage have declined steadily in most of Smith and Mason Valleys since 1960. Groundwater levels around Schurz, Nevada, have changed little during the past 50 years. In the Whisky Flat area south of Hawthorne, Nevada, agricultural and municipal pumpage has lowered groundwater levels since 1956. The water-level decline in Walker Lake since 1882 has caused the surrounding alluvial aquifer to drain and groundwater levels to decline. The Wabuska streamflow-gaging station in northern Mason Valley demarcates the upper and lower Walker River basin. The hydrology of the lower Walker River basin is considerably different than the upper basin. The upper basin consists of valleys separated by consolidated-rock mountains. The alluvial aquifer in each valley thins or pinches out at the downstream end, forcing most groundwater to discharge along the river near where the river is gaged. The lower Walker River basin is one surface-water/groundwater system of losing and gaining reaches from Wabuska to Walker Lake, which makes determining stream losses and the direction and amount of subsurface flow difficult. Isotopic data indicate surface water and groundwater in the lower Walker River basin are from two sources of precipitation that have evaporated. The Walker River, groundwater along the Wassuk Range, and Walker Lake plot along one evaporation line. Groundwater along th

Lopes, Thomas J.; Allander, Kip K.

2009-01-01

142

Sandpile models and random walkers on finite lattices.  

PubMed

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

Shilo, Yehiel; Biham, Ofer

2003-06-10

143

Virtual Slope Control of a Forward Dynamic Bipedal Walker  

PubMed Central

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.

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

2006-01-01

144

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

145

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

PubMed Central

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

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

2008-01-01

146

Scalar field dynamics in Friedmann-Robertson-Walker spacetimes  

SciTech Connect

We study the nonlinear dynamics of quantum fields in matter- and radiation-dominated universes, using the nonequilibrium field theory approach combined with the nonperturbative Hartree and the large N approximations. We examine the phenomenon of explosive particle production due to spinodal instabilities and parametric amplification in expanding universes with and without symmetry breaking. For a variety of initial conditions, we compute the evolution of the inflaton, its quantum fluctuations, and the equation of state. We find explosive growth of quantum fluctuations, although particle production is somewhat sensitive to the expansion of the universe. In the large N limit for symmetry-breaking scenarios, we determine generic late time solutions for any flat Friedmann-Robertson-Walker (FRW) cosmology. We also present a complete and numerically implementable renormalization scheme for the equation of motion and the energy momentum tensor in flat FRW cosmologies. In this scheme the renormalization constants are independent of time and of the initial conditions. {copyright} {ital 1997} {ital The American Physical Society}

Boyanovsky, D. [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Cormier, D.; Holman, R. [Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); de Vega, H.J. [Laboratoire de Physique Theorique et Hautes Energies Universite Pierre et Marie Curie (Paris VI), Tour 16, 1er. etage, 4, Place Jussieu 75252 Paris, Cedex 05 (France); Singh, A.; Srednicki, M. [Department of Physics, University of California, Santa Barbara, California 93106 (United States)

1997-08-01

147

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

2007-05-04

148

Einstein energy associated with the Friedmann-Robertson-Walker metric  

NASA Astrophysics Data System (ADS)

Following Einstein’s definition of Lagrangian density and gravitational field energy density (Einstein in Ann Phys Lpz 49:806, 1916, Einstein in Phys Z 19:115, 1918, Pauli in Theory of Relativity, B.I. Publications, Mumbai, 1963), Tolman derived a general formula for the total matter plus gravitational field energy ( P 0) of an arbitrary system (Tolman in Phys Rev 35:875, 1930, Tolman in Relativity, Thermodynamics & Cosmology, Clarendon Press, Oxford, 1962, Xulu in hep-th/0308070, 2003). For a static isolated system, in quasi-Cartesian coordinates, this formula leads to the well known result {P_0 = int sqrt{-g} (T_0^0 - T_1^1 - T_2^2 - T_3^3) d^3 x,} where g is the determinant of the metric tensor and {T^a_b} is the energy momentum tensor of the matter. Though in the literature, this is known as “Tolman Mass”, it must be realized that this is essentially “Einstein Mass” because the underlying pseudo-tensor here is due to Einstein. In fact, Landau-Lifshitz obtained the same expression for the “inertial mass” of a static isolated system without using any pseudo-tensor at all and which points to physical significance and correctness of Einstein Mass (Landau, Lifshitz in The Classical Theory of Fields, Pergamon Press, Oxford, 1962)! For the first time we apply this general formula to find an expression for P 0 for the Friedmann-Robertson-Walker (FRW) metric by using the same quasi-Cartesian basis. As we analyze this new result, it transpires that, physically, a spatially flat model having no cosmological constant is preferred. Eventually, it is seen that conservation of P 0 is honoured only in the static limit.

Mitra, Abhas

2010-03-01

149

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

150

Exact distributions of the number of distinct and common sites visited by N independent random walkers.  

PubMed

We study the number of distinct sites S(N)(t) and common sites W(N)(t) visited by N independent one dimensional random walkers, all starting at the origin, after t time steps. We show that these two random variables can be mapped onto extreme value quantities associated with N independent random walkers. Using this mapping, we compute exactly their probability distributions P(N)(d)(S,t) and P(N)(c)(W,t) for any value of N in the limit of large time t, where the random walkers can be described by Brownian motions. In the large N limit one finds that S(N)(t)/?t?2?(log N)+s/(2?(log N)) and W(N)(t)/?t?w/N where s and w are random variables whose probability density functions are computed exactly and are found to be nontrivial. We verify our results through direct numerical simulations. PMID:23767707

Kundu, Anupam; Majumdar, Satya N; Schehr, Grégory

2013-05-29

151

Mary Edwards Walker, M.D.: a feminist physician a century ahead of her time.  

PubMed

In her teens, Mary Edwards Walker already wore the "bloomer" outfit began to campaign for reforming the "unhygienic" clothing of women. Assertively, she attended medical school and earned her M.D. degree. Due to prejudice, her practice did not flourish and she moved to Washington to offer her medical services to the Union as the Civil War began. Rebuffed by the male medical bureaucrats, she volunteered her services anyway. Eventually, she was awarded the Congressional Medal of Honor, the only women to ever gain such distinction. After the war, Walker became a journalist, an author of two sensational books, a political lobbyist, a suffrage campaigner, a professional and public lecturer, an ardent dress reformer, a peace activist, a Utopianist and a women's right advocate. Light-years ahead of her times, Dr. Walker was an intelligent, independent, irrepressible and indefatigable proponent for a host of worthy causes. PMID:8726211

Spiegel, A D; Suskind, P B

1996-06-01

152

Removable cast walker boots yield greater forefoot off-loading than total contact casts  

PubMed Central

Background Elevated plantar loading has been implicated in the etiology of plantar ulceration in individuals with diabetes mellitus and peripheral neuropathy. Total contact casts and cast walker boots are common off-loading strategies to facilitate ulcer healing and prevent re-ulceration. The purpose of this study was to compare off-loading capabilities of these strategies with respect to plantar loading during barefoot walking. Methods Twenty-three individuals with diabetes, peripheral neuropathy, and plantar ulceration were randomly assigned to total contact cast (N=11) or removable cast walker boot (N=12). Each subject underwent plantar loading assessment walking barefoot and wearing the off-loading device. Analysis of covariance was used to compare loading patterns in the off-loading devices for the whole foot, hindfoot, midfoot, and forefoot while accounting for walking speed and barefoot loading. Findings For the foot as a whole, there were no differences in off-loading between the two techniques. Subjects wearing cast walker boots had greater reductions in forefoot peak pressure, pressure-time integral, maximum force, and force-time integral with respect to barefoot walking. Healing times were similar between groups, but a greater proportion of ulcers healed in total contact casting compared to cast walker boots. Interpretation In subjects with diabetes, peripheral neuropathy, and plantar ulceration, cast walker boots provided greater load reduction in the forefoot, the most frequent site of diabetic ulceration, though a greater proportion of subjects wearing total contact casts experienced ulcer healing. Taken together, the less effective ulcer healing in cast walker boots despite superior forefoot off-loading suggests an important role for patient compliance in ulcer healing.

Gutekunst, David J.; Hastings, Mary K.; Bohnert, Kathryn L.; Strube, Michael J.; Sinacore, David R.

2011-01-01

153

Moisture budget in the tropics and the Walker circulation  

NASA Astrophysics Data System (ADS)

Moisture budget in the tropics is studied for two contrasting years, 1987 (El Niño) and 1988 (La Niña), and for two seasons, December, January, and February (DJF) and June, July, and August (JJA). To evaluate the moisture budget, data from the National Centers for Environmental Prediction (NCEP) reanalysis are used. First, the mean rainfall and evaporation characteristics of the NCEP reanalysis for January, April, July, and October are compared with other independent data. The general precipitation zones associated with the large-scale features such as Intertropical Convergence Zone (ITCZ), South Pacific Convergence Zone (SPCZ), and South Atlantic Convergence Zone (SACZ) seem to be captured by the NCEP reanalysis. However, the seasonal variations, as seen in other data, are not reproduced well. Characteristics of ITCZ in the eastern Pacific is not well reproduced in the NCEP reanalysis data. The overall characteristics of latent heat flux (evaporation) in the NCEP reanalysis seem to be in qualitative agreement with other independent data. However, there are quantitative differences. The differences in rainfall over the western Pacific between DJF 1986/1987 (El Niño) and DJF 1988/1989 (La Niña) are associated with the differences in the position and intensity of SPCZ. The SPCZ is more intense in the El Niño year and is displaced northeastward. Northeast Brazil experienced higher rainfall in DJF 1988/1989 than in DJF 1986/1987. During the boreal summer (monsoon) season (JJA), rainfall was higher in 1988 over India than in 1987. The NCEP rainfall data are compared with the rainfall data from Schemm et al. and Huffman et al. The NCEP reanalysis seems to underestimate rainfall over the equatorial eastern Pacific. Higher precipitable water is found over the regions of intense convection such as SACZ, SPCZ, ITCZ, and the monsoon trough in JJA. The NCEP reanalysis seems to capture the general characteristics of vertically integrated moisture transport such as the general westward transport in the tropics, cross-equatorial moisture transport over the Indian Ocean with high values near the Somali coast in JJA. Over the western Pacific the differences between the two periods are associated with differences in moisture convergence but not evaporation. The increment term (Dc) shows large values over the mountainous regions. The evaluation of moisture budget of the Walker circulation shows that over the western Pacific the large differences in precipitation between the two contrasting years are accounted mainly by the differences in moisture flux convergence. This verifies the important role of moisture convergence in this region as inferred indirectly by Cornejo-Garrido and Stone. However, over the Amazon region, evapotranspiration seems to play an important role in the local precipitation.

Rao, V. Brahmananda; Chapa, S. R.; Cavalcanti, I. F. A.

1998-06-01

154

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

155

Suppression of Walker breakdown in magnetic domain wall propagation through structural control of spin wave emission  

NASA Astrophysics Data System (ADS)

The control of individual magnetic domain walls has potential for future spintronic memory and data processing applications. The speed and reliability of such devices are determined by the dynamic properties of the domain walls. Typically, spin precession limitations lead to Walker breakdown, limiting wall velocity resulting in low mobility. Here, we show the suppression of Walker breakdown by the careful design of small amplitude periodic nanowire structuring to match the periodicity of domain wall spin structure transformations. This opens up a channel for energy dissipation via spin wave emission, allowing a domain wall to maintain its spin structure during propagation.

Burn, David M.; Atkinson, Del

2013-06-01

156

[Cellular proliferation kinetics of Walker carcinosarcoma, Zajdela's ascitic hepatoma and their metastases to the lymph nodes].  

PubMed

The cell cycle of Walker carcinoma, Zajdela's hepatoma and their metastases into regional lymph nodes are studied. It is shown that cell cycle of metastases is shorter and the labeling index is higher than in primary tumours. The cell cycle shortening in Walker carcinosarcoma metastases is associated with a decrease in the duration of all its phases. The cell cycle of Zajdela's hepatoma metastases decreases with the S-phase length. The cell loss factor of primary tumours is less than that of their metastases. The results of the autoradiographic study correlate with the previously studied sensitivity of primary tumours and metastases to chemotherapy. PMID:4065018

Kiseleva, E G

1985-01-01

157

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

158

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.

159

A Seeded Image Segmentation Framework Unifying Graph Cuts And Random Walker Which Yields A New Algorithm  

Microsoft Academic Search

In this work, we present a common framework for seeded image segmentation algorithms that yields two of the lead- ing methods as special cases - The Graph Cuts and the Ran- dom Walker algorithms. The formulation of this common framework naturally suggests a new, third, algorithm that we develop here. Specifically, the former algorithms may be shown to minimize a

Ali Kemal Sinop; Leo Grady

2007-01-01

160

Experimental study of a parametrically excited dynamic bipedal walker with counterweights  

Microsoft Academic Search

This paper reports some interesting results on our experimental study of parametrically excited dynamic bipedal walking. We describe the details of the walking machine that has telescopic legs, semicircular feet, free hip-joint and counterweights. The walker can sustain stable dynamic walking on level ground based on mechanical energy restoration in accordance with the principle of parametric excitation utilizing the effects

Takeshi Hayashi; Fumihiko Asano; Zhi-Wei Luo; Akinori Nagano; Kazuaki Kaneko; Atsuo Kato

2009-01-01

161

Nutrient discharge from Walker Branch Watershed. [N, P, K, Ca, Mg, Na, S  

Microsoft Academic Search

Streamflow discharge of nutrient elements (N, P, K, Ca, Mg, Na and S) has been studied on Walker Branch Watershed for up to six years. Annual discharges of N, P and S are less than atmospheric inputs whereas Ca, Mg, K and Na discharges exceed atmospheric inputs. Seasonal nutrient discharges are dependent on water yield. Concentration behavior of nutrients during

G. S. Henderson; A. Hunley; W. Selvidge

1977-01-01

162

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…

Matunda, Robert Stephen Mokaya

2009-01-01

163

The effects of habitual footwear use: foot shape and function in native barefoot walkers  

Microsoft Academic Search

The human foot was anatomically modern long before footwear was invented, and is adapted to barefoot walking on natural substrates. Understanding the biomechanics of habitually barefoot walkers can provide novel insights both for anthropologist and for applied scientists, yet the necessary data is virtually non-existent. To start assessing morphological and functional effects of the habitual use of footwear, we have

K. D'Aoutab; T. C. Patakyc; D. De Clercqd; P. Aertsad

2009-01-01

164

A Simple Model of a Convectively Coupled Walker Circulation Using the Weak Temperature Gradient Approximation  

Microsoft Academic Search

An idealized model of a Walker circulation based on the weak temperature gradient (WTG) approximation and a single baroclinic vertical mode for all fields is analyzed. The circulation is forced by a sinusoidal variation of sea surface temperature (SST). A simple feedback of deep convective cloud radiative forcing on tropospheric radiative cooling is included, and a moist convective adjustment is

Christopher S. Bretherton; Adam H. Sobel

2002-01-01

165

Safety in numbers: more walkers and bicyclists, safer walking and bicycling  

Microsoft Academic Search

Objective: To examine the relationship between the numbers of people walking or bicycling and the frequency of collisions between motorists and walkers or bicyclists. The common wisdom holds that the number of collisions varies directly with the amount of walking and bicycling. However, three published analyses of collision rates at specific intersections found a non-linear relationship, such that collisions rates

P L Jacobsen

2003-01-01

166

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

Microsoft Academic Search

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

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

2011-01-01

167

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

Microsoft Academic Search

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

Sébastien Krut; Michel Benoit; Etienne Dombre; François Pierrot

2010-01-01

168

THE APOCALYPTIC VISION IN THE FICTION OF WALKER PERCY (LOUISIANA, SOUTHERN, RELIGION, TWENTIETH-CENTURY)  

Microsoft Academic Search

The novels of Walker Percy comprise books of revelations, His protagonists begin as seers, usually in a quite physical fashion. By suddenly performing an act of attention to the moment at hand, they experience an apocalyptic unveiling of mysteries and disclosure of secrets. As the world and time come back to these seers, they come to themselves and recover consciousness.

GARY MARTIN CIUBA

1986-01-01

169

The Moviegoer's Cartesian Theater: Moviegoing as Walker Percy's Metaphor for the Cartesian Mind  

Microsoft Academic Search

Binx Bolling is the moviegoing protagonist of The Moviegoer (1961), Walker Percy's first novel. In an interview, Percy once referred to Binx as a “victim” of Descartes. Did Percy intend some connection between Binx's moviegoing and his unfortunate, Cartesian heritage? In this essay, I argue that Percy used Binx's moviegoing as a metaphor for his having a Cartesian mind. As

Woods Nash

2011-01-01

170

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

171

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.

172

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

173

The collapse of voids in a Roberston-Walker universe with nonzero spatial curvature  

Microsoft Academic Search

We consider the model of a spherical void (or its precursor) with heat conducting perfect fluid in Region I with Maiti metric (1982) surrounded by a spherical shell filled with radiation (Region II) having Vaidya metric. The combination is embedded in Robertson-Walker (RW) Universe in Region III. Earlier, Mandal and Banerji (1998) took RW Universe with zero spatial curvature and

M. K. Ray; S. Chaudhuri; S. Banerji

2000-01-01

174

Quantitative Assessment of Brainstem Development in Joubert Syndrome and Dandy-Walker Syndrome  

Microsoft Academic Search

Key features of Joubert syndrome include developmental delay, hypotonia, hyperpnea and apnea, oculomotor apraxia, and the presence of the molar tooth sign on axial imaging through the brainstem isthmus—the junction of the pons and mesencephalon. Interestingly, 1 in 10 patients with Joubert syndrome has abnormal cerebrospinal fluid collections misdiagnosed as Dandy-Walker variants. Because of important differences in patient management, genetic

Bernard L. Maria; Alilreza Bozorgmanesh; Kimberly N. Kimmel; Douglas Theriaque; Ronald G. Quisling

2001-01-01

175

Joseph Walker, a Black Playwright, Exhorts Counselors and Black People to Deal With Themselves  

ERIC Educational Resources Information Center

|This is an interview with Joseph Walker, black playwright. He attempts to reflect back to the black community their experience in a white controlled world. In this interview, he discusses his views of the black experience, the pressures on man-woman relationships, and the role of black psychiatry. (NG)|

Walker, Joseph

1976-01-01

176

Mary Edwards Walker, M.D.: A feminist physician a century ahead of her time  

Microsoft Academic Search

In her teens, Mary Edwards Walker already wore the “bloomer” outfit and began to campaign for reforming the “unhygienic” clothing of women. Assertively, she attended medical school and earned her M.D. degree. Due to prejudice, her practice did not flourish and she moved to Washington to offer her medical services to the Union as the Civil War began. Rebuffed by

Allen D. Spiegel; Peter B. Suskind

1996-01-01

177

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

178

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.

179

TOWARDS THE ADAPTIVE IDENTIFICATION OF WALKERS: AUTOMATEDFEATURE SELECTION OF FOOTSTEPS USING DISTINCTION-SENSITIVE LVQ  

Microsoft Academic Search

We applied a method called Distinction-Sensitive Learning Vector Quantization (DSLVQ) to the classification of foot- steps. The measurements were made by a pressure-sensitive floor, which is part of the smart sensing living room in our research laboratory. The aim is to identify walkers based on their single footsteps. DSLVQ is an extended version of Learning Vector Quantization (LVQ), and it

Jaakko Suutala; Infotech Oulu

180

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

181

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

Microsoft Academic Search

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

R. M. Hennig

1988-01-01

182

Revised Flood Hazard Data on West Chickamauga Creek in the Vicinity of Walker County, Georgia.  

National Technical Information Service (NTIS)

This report provides flood hazard information for the portion of West Chickamauga Creek (stream mile 20.05 to mile 24.86) which lies within the unincorporated area of Walker County, Georgia. Local officials may wish to use the maps and profiles contained ...

1982-01-01

183

Revised flood hazard data on west Chickamauga Creek in the vicinity of Walker County, Georgia  

SciTech Connect

This report provides flood hazard information for the portion of West Chickamauga Creek (stream mile 20.05 to mile 24.86) which lies within the unincorporated area of Walker County, Georgia. Local officials may wish to use the maps and profiles contained in this report to supplement those prepared by FEMA in carrying out their floodplain management program activities.

Not Available

1982-12-01

184

First Law of Thermodynamics and Friedmann Equations of Friedmann Robertson Walker Universe  

Microsoft Academic Search

Applying the first law of thermodynamics to the apparent horizon of a Friedmann Robertson Walker universe and assuming the geometric entropy given by a quarter of the apparent horizon area, we derive the Friedmann equations describing the dynamics of the universe with any spatial curvature. Using entropy formulae for the static spherically symmetric black hole horizons in Gauss Bonnet gravity

Rong-Gen Cai; Sang Pyo Kim

2005-01-01

185

Results of Topical Myeloperoxidase/Glucose Oxidase/Glucose in the Walker-Mason Burn Model.  

National Technical Information Service (NTIS)

One area of research at tile ISR is soft tissue trauma encompassing infection control and wound healing. Treatments are evaluated in vivo using the Walker-Mason model which is a fall thickness thermal injury and infection model. We have identified a novel...

D. G. Baer J. R. Reeder

2005-01-01

186

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

187

Promoting Ambulation Responses among Children with Multiple Disabilities through Walkers and Microswitches with Contingent Stimuli  

ERIC Educational Resources Information Center

|Children with severe or profound intellectual and motor disabilities often present problems of balance and ambulation and spend much of their time sitting or lying, with negative consequences for their development and social status. Recent research has shown the possibility of using a walker (support) device and microswitches with preferred…

Lancioni, Giulio E.; Singh, Nirbhay N.; O'Reilly, Mark F.; Sigafoos, Jeff; Oliva, Doretta; Smaldone, Angela; La Martire, Maria L.; Stasolla, Fabrizio; Castagnaro, Francesca; Groeneweg, Jop

2010-01-01

188

Promoting Ambulation Responses among Children with Multiple Disabilities through Walkers and Microswitches with Contingent Stimuli  

ERIC Educational Resources Information Center

Children with severe or profound intellectual and motor disabilities often present problems of balance and ambulation and spend much of their time sitting or lying, with negative consequences for their development and social status. Recent research has shown the possibility of using a walker (support) device and microswitches with preferred…

Lancioni, Giulio E.; Singh, Nirbhay N.; O'Reilly, Mark F.; Sigafoos, Jeff; Oliva, Doretta; Smaldone, Angela; La Martire, Maria L.; Stasolla, Fabrizio; Castagnaro, Francesca; Groeneweg, Jop

2010-01-01

189

Walker Carcinoma 256: A Model for Studies on Tumor-Induced Anorexia and Cachexia  

Microsoft Academic Search

Data on anorexia and cachexia induced by Walker carcinoma 256 in Sprague-Dawley rats were analyzed in order to standardize an experimental model using a statistical (nondeterministical) procedure for assessing the efficacy of potential orexigenic agents. This model was characterized by a mean survival time of 14 ± 1 days and by food intake and body weight loss starting from day

Amalia Guaitani; Martino Recchia; Miriana Carli; Maurizio Rocchetti; Ivan Bartošek; Silvio Garattini

1982-01-01

190

Physical Activity Patterns among Walkers and Compliance with Public Health Recommendations.  

ERIC Educational Resources Information Center

|Assessed data from the 1998 Behavioral Risk Factor Surveillance System to determine the prevalence of walking for physical activity and the proportions of walkers who met current public health physical activity recommendations. Results indicated that in 1998, approximately 38.6 percent of U.S. adults walked for physical activity. Less than 40…

Rafferty, Ann P.; Reeves, Mathew J.; McGee, Harry B.; Pivarnik, James M.

2002-01-01

191

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

192

GPS constraints on shear accommodation in the northern Walker Lane, western Nevada, USA  

NASA Astrophysics Data System (ADS)

The Walker Lane is a zone of active intracontinental transtension that accommodates approximately 10 mm/yr of right-lateral deformation, up to 20-25% of Pacific-North America relative plate motion. Between Walker Lake and Lake Tahoe, the Walker Lane lacks optimally oriented strike-slip faults to accommodate northwest-directed dextral shear. In this region Quaternary deformation appears to be concentrated in a northwest-trending series of north-striking, normal fault-bounded basins. To address the question of how shear is transferred through this portion of the Walker Lane, we combine GPS data from the University of Nevada, Reno’s semi-continuous MAGNET GPS network with observations from EarthScope’s Plate Boundary Observatory to present a new velocity field for the Walker Lane with an average station spacing of 20 km. Measurements in MAGNET (http://geodesy.unr.edu/networks) began in January 2004 and now provide time series of up to 6 years for the longest running sites and >3 years for all sites. Together with recent improvements in GPS data processing models using the GIPSY-OASIS II software, this allows us to estimate rates with uncertainty well below 1 mm/yr. These recent improvements include the use of reprocessed GPS orbits from the IGS Analysis Center at JPL. Our GPS processing now includes satellite and station antenna calibrations, random-walk tropospheric zenith delay and gradients using the GMF mapping function, second-order ionospheric corrections, global-scale ambiguity resolution using our custom Ambizap software, and our custom Great Basin spatially-filtered reference frame. The velocity solution shows a smooth and continuous increase in shear across the Walker Lane in addition to NW-SE directed extension. We use a block model driven by GPS velocities to estimate the role that vertical axis rotation of fault-bounded blocks and slip on basin-bounding faults play in shear accommodation. The block model also allows us to incorporate published geologic fault slip rates and thus test the compatibility of the available geodetic and geologic datasets for the northern Walker Lane.

Bormann, J. M.; Hammond, W. C.; Kreemer, C. W.; Blewitt, G.; Wesnousky, S. G.

2009-12-01

193

Strain Partitioning in the Northern Walker Lane and Western Basin and Range from GPS Measurements  

NASA Astrophysics Data System (ADS)

The northern Walker Lane, in the western Basin and Range Province of the United States, is a complex system of dextral, normal and sinestral faults that work together to accommodate approximately 9 mm/yr of relative motion between the Sierra Nevada/Great Valley block and the more slowly extending Province. GPS measurements made using the BARGEN, EarthScope PBO and MAGNET GPS networks since 2004 are now providing improved resolution of deformation patterns and crustal fault slip rates inside the Walker Lane and western Basin and Range. We have processed all the GPS data as part of a uniform global solution, and filtered the solution on a Great Basin spatial scale to obtain rates of motion of the Walker Lane crust with respect to North America. Using these rates we have constrained slip rates on regional faults using a block model whose boundaries conform to Quaternary surface rupture geometries. These results show a very strong correlation between the geologic domains and style of strain measured with GPS. In particular, east of the Walker Lane, where the topography and crustal faulting are characteristic of classic Basin and Range tectonic extension, the GPS velocities show a highly uniform southeast to northwest uniaxial extension of 2.5 mm/yr distributed over 250 km. This uniform extension implies normal slip rates of approximately 0.1 mm/yr on average for each fault (horizontal extension). The transition between Basin and Range morphology and the Walker Lane is matched in the GPS velocities by a transition from uniaxial extension to transtension that is resolved into dextral slip on northwest trending faults, with minor contributions from left lateral slip on northeast striking faults and normal slip. Right oblique extension is well-distributed across the Walker Lane, with most faults contributing some slip to accommodate the overall slip budget. The greatest slip rates occur on the western and eastern margins, and by far the greatest amount of normal slip occurs in the westernmost fault systems near the Sierra Nevada crest, Lake Tahoe, and Carson Range faults where horizontal extension rates normal to the fault are as high as 1.8 mm/yr. Normal slip rates elsewhere in the Walker Lane are similar in rate to the rest of the Basin and Range. The Mohawk Valley fault slips faster than any fault in the entire system, about 2.8 mm/yr of dextral slip. These results suggest that contemporary extension on normal faults nearest the Sierra Nevada Range Front may drive the seismic hazard for the nearby Reno/Tahoe metropolitan areas.

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

2009-05-01

194

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

195

Ground reaction force and 3D biomechanical characteristics of walking in short-leg walkers.  

PubMed

Short-leg walking boots offer several advantages over traditional casts. However, their effects on ground reaction forces (GRF) and three-dimensional (3D) biomechanics are not fully understood. The purpose of the study was to examine 3D lower extremity kinematics and joint dynamics during walking in two different short-leg walking boots. Eleven (five females and six males) healthy subjects performed five level walking trials in each of three conditions: two testing boot conditions, Gait Walker (DeRoyal Industries, Inc.) and Equalizer (Royce Medical Co.), and one pair of laboratory shoes (Noveto, Adidas). A force platform and a 6-camera Vicon motion analysis system were used to collect GRFs and 3D kinematic data during the testing session. A one-way repeated measures analysis of variance (ANOVA) was used to evaluate selected kinematic, GRF, and joint kinetic variables (p<0.05). The results revealed that both short-leg walking boots were effective in minimizing ankle eversion and hip adduction. Neither walker increased the bimodal vertical GRF peaks typically observed in normal walking. However, they did impose a small initial peak (<1BW) earlier in the stance phase. The Gait Walker also exhibited a slightly increased vertical GRF during midstance. These characteristics may be related to the sole materials/design, the restriction of ankle movements, and/or the elevated heel heights of the tested walkers. Both walkers appeared to increase the demand on the knee extensors while they decreased the demand of the knee and hip abductors based on the joint kinetic results. PMID:16414263

Zhang, Songning; Clowers, Kurt G; Powell, Douglas

2006-01-18

196

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

197

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

198

Production Dynamics of Alloperla Mediana Banks (Plecoptera:Chloroperlidae) and Diplectrona Modesta Banks (Trichoptera:Hydropsychidae) in Walker Branch, Tennessee.  

National Technical Information Service (NTIS)

The production dynamics of the immature stages of Alloperla mediana Banks, a carnivorous stonefly, and Diplectrona modesta Banks, an omnivorous caddisfly, are described in Walker Branch, a woodland stream in eastern Tennessee. Data are based on benthos sa...

R. M. Cushman J. W. Elwood S. G. Hildebrand

1975-01-01

199

Simultaneous creation of electron-positron pairs and photons in Robertson-Walker universes with statically bounded expansion.  

National Technical Information Service (NTIS)

Based upon quantum electrodynamics in Robertson-Walker flat universes we present a thorough analysis of the creation of mutually interacting electron-positron pairs and photons from vacuum. Therefore we discuss at least qualitatively all processes contrib...

K. H. Lotze

1989-01-01

200

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

201

Influence of lodgement site on the proliferation of metastases of Walker 256 carcinoma in the rat.  

PubMed

The growth of s.c. Walker 256 carcinoma was found to be independent of secondary growths induced by i.v. injection. Tumour cells injected i.v. lodged mainly in the lungs, with small clusters of cells in the lymph nodes. The rate of cellular proliferation of these secondary growths of Walker carcinoma was significantly higher than that observed in the s.c. tumour. In addition, host lung tissue was found to inhibit the development of metastases, and it is postulated that the host tissue may produce a diffusible inhibitor and that differences in the effectiveness of these humoral factors may account, in part, for locational differences in tumour growth patterns. PMID:619960

Bellamy, D; Hinsull, S M

1978-01-01

202

Emergence of space and the general dynamic equation of the Friedmann-Robertson-Walker universe  

NASA Astrophysics Data System (ADS)

A novel idea—that the cosmic acceleration can be understood from the perspective that spacetime dynamics is an emergent phenomenon—was proposed by T. Padmanabhan. The Friedmann equations of a Friedmann-Robertson-Walker universe can be derived from different gravity theories with different modifications of Padmanabhan’s proposal. In this paper, a unified formula is proposed, in which those modifications can be treated as special cases when the formula is applied to different universe radii. Furthermore, the dynamic equations of a Friedmann-Robertson-Walker universe in the f(R) theory and deformed Ho?ava-Lifshitz theory are investigated. The results show the validity of our proposed formula.

Ai, Wen-Yuan; Hu, Xian-Ru; Chen, Hua; Deng, Jian-Bo

2013-10-01

203

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

204

Decoherence induced by a chaotic enviroment: A quantum walker with a complex coin  

SciTech Connect

We study the differences between the processes of decoherence induced by chaotic and regular environments. For this we analyze a family of simple models that contain both regular and chaotic environments. In all cases the system of interest is a ''quantum walker,'' i.e., a quantum particle that can move on a lattice with a finite number of sites. The walker interacts with an environment which has a D-dimensional Hilbert space. The results we obtain suggest that regular and chaotic environments are not distinguishable from each other in a (short) time scale t*, which scales with the dimensionality of the environment as t*{proportional_to}log{sub 2}(D). However, chaotic environments continue to be effective over exponentially longer time scales while regular environments tend to reach saturation much sooner. We present both numerical and analytical results supporting this conclusion. The family of chaotic evolutions we consider includes the so-called quantum multibaker map as a particular case.

Ermann, Leonardo [Departamento de Fisica, Comision Nacional de Energia Atomica, Avenida del Libertador 8250 (C1429BNP), Buenos Aires (Argentina); Departamento de Fisica, FCEyN, UBA, Pabellon 1 Ciudad Universitaria, 1428 Buenos Aires (Argentina); Paz, Juan Pablo [Departamento de Fisica, FCEyN, UBA, Pabellon 1 Ciudad Universitaria, 1428 Buenos Aires (Argentina); Theoretical Division, LANL, MSB213, Los Alamos, New Mexico 87545 (United States); Saraceno, Marcos [Departamento de Fisica, Comision Nacional de Energia Atomica, Avenida del Libertador 8250 (C1429BNP), Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin, Alem 3901 (B1653HIM), Villa Ballester (Argentina)

2006-01-15

205

A Novel Function for the Conserved Glutamate Residue in the Walker B Motif of Replication Factor C  

PubMed Central

In all domains of life, sliding clamps tether DNA polymerases to DNA to increase the processivity of synthesis. Clamp loaders load clamps onto DNA in a multi-step process that requires ATP binding and hydrolysis. Like other AAA+ proteins, clamp loaders contain conserved Walker A and Walker B sequence motifs, which participate in ATP binding and hydrolysis, respectively. Mutation of the glutamate residue in Walker B motifs (or DExx-boxes) in AAA+ proteins typically reduces ATP hydrolysis by as much as a couple orders of magnitude, but has no effect on ATP binding. Here, the Walker B Glu in each of the four active ATP sites of the eukaryotic clamp loader, RFC, was mutated to Gln and Ala separately, and ATP binding- and hydrolysis-dependent activities of the quadruple mutant clamp loaders were characterized. Fluorescence-based assays were used to measure individual reaction steps required for clamp loading including clamp binding, clamp opening, DNA binding and ATP hydrolysis. Our results show that the Walker B mutations affect ATP-binding-dependent interactions of RFC with the clamp and DNA in addition to reducing ligand-dependent ATP hydrolysis activity. Here, we show that the Walker B glutamate is required for ATP-dependent ligand binding activity, a previously unknown function for this conserved Glu residue in RFC.

Chiraniya, Ankita; Finkelstein, Jeff; O'Donnell, Mike; Bloom, Linda B.

2013-01-01

206

Distance-Redshift in Inhomogeneous Omega0=1 Friedmann-Lemaître-Robertson-Walker Cosmology  

Microsoft Academic Search

Distance-redshift relations are given in terms of associated Legendre functions for partially filled beam observations in spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) cosmologies. These models are dynamically pressure-free and flat FLRW on large scales but, because of mass inhomogeneities, differ in their optical properties. The partially filled beam area-redshift equation is a Lamé equation for arbitrary FLRW models and is shown to

R. Kantowski; R. C. Thomas

2001-01-01

207

Absorption of a self-avoiding random walker by a random trap distribution  

Microsoft Academic Search

A particle performing a self-avoiding random walk is considered on a lattice in any number of dimensions d, which contains a fraction q of randomly distributed impurity sites. An impurity is assumed to trap the walker when stepped on. The author finds the average time to trapping to be lambda (1-q)\\/(q-(1-Kc)), where Kc and gamma are the inverse critical temperature

F. Tanaka

1983-01-01

208

An almost-Robertson-Walker universe model and the equivalence classes of perturbations: nonbarotropic perfect fluids  

Microsoft Academic Search

A new covariant and gauge-invariant treatment of perturbations, which is applicable to the case of an almost-Robertson-Walker universe dominated by a general perfect fluid with two essential thermodynamic variables, is presented. Beginning from the geometrical foundation, this paper proposes to define gauge-invariant perturbations as the equivalence classes of tangents to one-parameter families of exact solutions of the nonlinear field equations.

Z. Banach; S. Piekarski

1996-01-01

209

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

Microsoft Academic Search

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

Robert C. Fletcheer

2006-01-01

210

Walker Percy's Alternative to Reductive Scientism in The Thanatos Syndrome  

Microsoft Academic Search

While Walker Percy's The Thanatos Syndrome shows how a reductive scientism always dehumanizes, it also suggests that human language—particularly of the sort we find in the literary arts—functions both as a testament to the reality of non-material things and as an impediment to the “progress” of scientism. This article first summarizes Percy's view of language and, second, examines how reading

Micah Mattix

2011-01-01

211

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

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

212

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…

Huber, Germaine W.

2009-01-01

213

Relaxation-time approximation for a Boltzmann gas in Robertson-Walker universe models  

Microsoft Academic Search

Given Einstein's theory of gravitation, the relaxation-time approximation for a general-relativistic Boltzmann equation is studied with a view to demonstrating its usefulness in the context of Robertson-Walker universe models. Solutions of the full nonlinear equations for the metric and the distribution function are examined, together with their relation to linearized perturbations. Emphasis is placed on finding analogs of the exact

Zbigniew Banach; Hanna Makaruk

1995-01-01

214

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

215

Why walkers slip: Shine is not a reliable cue for slippery ground  

Microsoft Academic Search

In a series of four studies, we investigated the visual cues that walkers use to predict slippery ground surfaces and tested\\u000a whether visual information is reliable for specifying low-friction conditions. In Study 1, 91% of participants surveyed responded\\u000a that they would use shine to identify upcoming slippery ground. Studies 2–4 confirmed participants' reliance on shine to predict\\u000a slip. Participants viewed

Amy S. Joh; Karen E. Adolph; Margot R. Campbell; Marion A. Eppler

2006-01-01

216

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

217

Triazophos resistance mechanisms in the rice stem borer ( Chilo suppressalis Walker)  

Microsoft Academic Search

A field population of the rice stem borer (Chilo suppressalis Walker) with 203.3-fold resistance to triazophos was collected. After 8-generation of continuous selection with triazophos in laboratory, resistance increased to 787.2-fold, and at the same time, the resistance to isocarbophos and methamidophos was also enhanced by 1.9- and 1.4-fold, respectively, implying some cross-resistance between triazophos and these two organophosphate insecticides.

Qu Mingjing; Han Zhaojun; Xu Xinjun; Yue lina

2003-01-01

218

Field Studies of Streamflow Generation Using Natural and Injected Tracers on Bickford and Walker Branch Watersheds  

Microsoft Academic Search

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 ²²²Rn as a tracer. The first of the two stages was

Genereux

1992-01-01

219

Studies of the properties of human origin recognition complex and its Walker A motif mutants.  

PubMed

The eukaryotic six-subunit origin recognition complex (ORC) governs the initiation site of DNA replication and formation of the prereplication complex. In this report we describe the isolation of the wild-type Homo sapiens (Hs)ORC and variants containing a Walker A motif mutation in the Orc1, Orc4, or Orc5 subunit using the baculovirus-expression system. Coexpression of all six HsORC subunits yielded a stable complex containing HsOrc subunits 1-5 (HsORC1-5) with virtually no Orc6 protein (Orc6p). We examined the ATPase, DNA-binding, and replication activities of these complexes. Similar to other eukaryotic ORCs, wild-type HsORC1-5 possesses ATPase activity that is stimulated only 2-fold by single-stranded DNA. HsORC1-5 with a mutated Walker A motif in Orc1p contains no ATPase activity, whereas a similar mutation of either the Orc4 or Orc5 subunit did not affect this activity. The DNA-binding activity of HsORC1-5, using lamin B2 DNA as substrate, is stimulated by ATP 3- to 5-fold. Mutations in the Walker A motif of Orc1p, Orc4p, or Orc5p reduced the binding efficiency of HsORC1-5 modestly (2- to 5-fold). Xenopus laevis ORC-depleted extracts supplemented with HsORC1-5 supported prereplication complex formation and X. laevis sperm DNA replication, whereas the complex with a mutation in the Walker A motif of the Orc1, Orc4, or Orc5 subunit did not. These studies indicate that the ATP-binding motifs of Orc1, Orc4, and Orc5 are all essential for the replication activity associated with HsORC. PMID:15618391

Giordano-Coltart, Jennifer; Ying, Carol Y; Gautier, Jean; Hurwitz, Jerard

2004-12-23

220

Observational evidences of Walker circulation change over the last 30 years contrasting with GCM results  

NASA Astrophysics Data System (ADS)

In order to examine the changes in Walker circulation over the recent decades, we analyzed the sea surface temperature (SST), deep convective activities, upper tropospheric moistening, sea level pressure (SLP), and effective wind in the boundary layer over the 30-year period of 1979-2008. The analysis showed that the eastern tropical Pacific has undergone cooling while the western Pacific has undergone warming over the past three decades, causing an increase in the east-west SST gradient. It is indicated that the tropical atmosphere should have responded to these SST changes; increased deep convective activities and associated upper tropospheric moistening over the western Pacific ascending region, increased SLP over the eastern Pacific descending region in contrast to decreased SLP over the western Pacific ascending region, and enhanced easterly wind in the boundary layer in response to the SLP change. These variations, recognized from different data sets, occur in tandem with each other, strongly supporting the intensified Walker circulation over the tropical Pacific Ocean. Since the SST trend was attributed to more frequent occurrences of central Pacific-type El Niño in recent decades, it is suggested that the decadal variation of El Niño caused the intensified Walker circulation over the past 30 years. An analysis of current climate models shows that model results deviate greatly from the observed intensified Walker circulation. The uncertainties in the current climate models may be due to the natural variability dominating the forced signal over the tropical Pacific during the last three decades in the twentieth century climate scenario runs by CMIP3 CGCMs.

Sohn, B. J.; Yeh, Sang-Wook; Schmetz, Johannes; Song, Hwan-Jin

2013-04-01

221

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

SciTech Connect

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

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

1997-07-01

222

Dynamic optimization of walker-assisted FES-activated paraplegic walking: Simulation and experimental studies.  

PubMed

In this paper, we propose a musculoskeletal model of walker-assisted FES-activated paraplegic walking for the generation of muscle stimulation patterns and characterization of the causal relationships between muscle excitations, multi-joint movement, and handle reaction force (HRF). The model consists of the lower extremities, trunk, hands, and a walker. The simulation of walking is performed using particle swarm optimization to minimize the tracking errors from the desired trajectories for the lower extremity joints, to reduce the stimulations of the muscle groups acting around the hip, knee, and ankle joints, and to minimize the HRF. The results of the simulation studies using data recorded from healthy subjects performing walker-assisted walking indicate that the model-generated muscle stimulation patterns are in agreement with the EMG patterns that have been reported in the literature. The experimental results on two paraplegic subjects demonstrate that the proposed methodology can improve walking performance, reduce HRF, and increase walking speed when compared to the conventional FES-activated paraplegic walking. PMID:23860368

Nekoukar, Vahab; Erfanian, Abbas

2013-07-13

223

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.

Weiss, H. B.

1996-01-01

224

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

225

Effect of chlorambucil and indomethacin on growth and prostaglandin levels in sensitive and resistant Walker carcinoma.  

PubMed

An analysis of the effect of combinations of chlorambucil and indomethacin, or chlorambucil and prostaglandin E2 (PGE2) on the growth of alkylating agent sensitive and resistant Walker carcinoma in vitro has been made by the isobologram approach. Indomethacin alone acts as a growth inhibitor of the Walker carcinoma. High concentrations of indomethacin (5 microgram/ml) act to inhibit the growth of the resistant line sub-additively with chlorambucil, whereas low concentrations act additively. For the sensitive line indomethacin acts either additively or supra-additively with chlorambucil at all concentrations employed. Both indomethacin and low concentrations of chlorambucil alone inhibit PGE2 secretion into the culture medium of both cell lines and an enhanced inhibition is seen with the combination. PGE2 itself acts as a growth inhibitor of both cell lines, although it causes greater growth inhibition of chlorambucil resistant Walker carcinoma (LD50 1.8 microgram/ml) than of the sensitive line. This correlates with a greater PGE2 secretion capacity by the resistant cell line (40 pg PGE2/ml medium/10(5) cells for the resistant tumour and 17 pg PGE2/ml medium/10(5) cells for the sensitive tumour). Combinations of PGE2 with chlorambucil inhibit growth either additively or sub-additively. It seems unlikely that inhibition of PGE2 secretion is responsible for the interactive effects of chlorambucil and indomethacin, since growth inhibition produced by the combination is not reversed by PGE2 at any of the concentrations employed. Possible mechanisms of the interactive effects are discussed. PMID:6949655

Tisdale, M J; Gibbs, J; Dobrzanski, R J

1982-03-15

226

Specificity of physiological adaptation to endurance training in distance runners and competitive walkers.  

PubMed

The present study was designed to evaluate the specificity of physiological adaptation to extra endurance training in five female competitive walkers and six female distance runners. The mean velocity (v) during training, corresponding to 4 mM blood lactate [onset of blood lactate accumulation (OBLA)] during treadmill incremental exercise (training v was 2.86 m.s-1, SD 0.21 in walkers and 4.02 m.s-1, SD 0.11 in runners) was added to their normal training programme and was performed for 20 min, 6 days a week for 8 weeks, and was called extra training. An additional six female distance runners performed only their normal training programme every day for about 120 min at an exercise intensity equivalent to their lactate threshold (LT) (i.e. a running v of about 3.33 m.s-1). After the extra training, there were statistically significant increases in blood lactate variables (i.e. oxygen uptake (VO2) at LT, v at LT, VO2 at OBLA, v at OBLA; P less than 0.05), and running v for 3,000 m (P less than 0.01) in the running training group. In the walking training group, there were significant increases in blood lactate variables (i.e., v at LT, v at OBLA; P less than 0.05), and walking economy. In contrast, there were no significant changes in lactate variables, running v and economy in the group of runners which carried out only the normal training programme. It is suggested that the changes in blood lactate variables such as LT and OBLA played a role in improving v of both the distance runners and the competitive walkers.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2282901

Yoshida, T; Udo, M; Chida, M; Ichioka, M; Makiguchi, K; Yamaguchi, T

1990-01-01

227

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

228

Contemporary Fault Slip Rates in the Southern Walker Lane from Block Modeling of GPS Data  

NASA Astrophysics Data System (ADS)

The southern Walker Lane is a right-lateral shear zone in western Nevada and eastern California that accommodates ~25% (9.3 ± 0.2 mm/yr) of the relative motion between the Pacific and North American plates. The region is characterized by discontinuous NNW-trending right-lateral strike-slip faults, and NE-trending, down-to-the-NW normal faults. The late Quaternary cumulative slip across the southern Walker Lane is only 1/2 the observed regional current geodetic rate of right-lateral shear. In order to better understand the modern distribution of strain accumulation and release across this region, we established a dense network of 50 new and existing campaign GPS monuments (from MAGNET and other networks). GPS data were processed using GIPSY-OASIS software to obtain sub-cm precision locations. To determine a new regional crustal velocity field we combine data from surveys of entirely new monuments only instrumented in 2010 and 2011 with existing monuments that were first instrumented as early as 1994, and reoccupied in 2010/11. We will report on initial velocity results for campaigns through 2011. As well, we will report on our successes with using the determined velocities in a modern regional block model (Meade and Loveless, BSSA 2009) to determine slip rates on individual faults in the southern Walker Lane. Elucidating slip on individual structures allows for a better accounting of slip across the region, and helps reveal distributed deformation that may not be preserved in the geologic record. These new results have important implications for the temporal and spatial distribution of strain accumulation and release along this portion of an evolving plate boundary.

Lifton, Z. M.; Frankel, K. L.; Johnson, C. W.; Newman, A. V.; Dixon, T.

2011-12-01

229

[Patterns of use, popular beliefs and proneness to accidents of a baby walker (go-cart). Bases for a health information campaign].  

PubMed

Baby walkers are a potential cause of accidents in infants from 6 months to 1 year of age. We conducted a study to determine the patterns of walker use, the different points of view of the parents and the baby walker-related injuries in our health district. For this purpose, between November 1, 1992 and January 31, 1993, a questionnaire was given to 207 parents of infants between the ages of 3 and 24 months in order to evaluate the socioeconomic situation and to determine the patterns of walker use. We found that 42% of the infants between 4.3 and 13.4 months of age had a baby walker and 46.7% of them used it daily. There was a significant inverse relationship between the walker usage and the maternal level of education. Of the infants who used walkers, 24.9% had experienced an accident (falls 76.2%, injuries 14.3% and hospital admission 4.8%). The accidents were significantly more common in boys. The advantages reported by parents (for using walkers) were: 46.3% none, 34.2% comfort, 10.9% infant amusement, 12.9% help to walk earlier. Dangers reported by the parents included: 27.2% none, 33.5% leg deformities, 43% accidents (33.5% injuries and 12% falling down stairs). In conclusion, our results show a slightly lower number of walker users and walker related accidents when compared to other reports. Parents have mistaken notions about the use of baby walkers. Hence, the need for continued health education campaigns related to this subject remain. PMID:8849083

Santos Serrano, L; Paricio Talayero, J M; Salom Pérez, A; Grieco Burucúa, M; Martín Ruano, J; Benlloch Muncharaz, M J; Llobat Estellés, T; Beseler Soto, B

1996-04-01

230

Chiral symmetry breaking and pair-creation mediated Walker breakdown in magnetic nanotubes  

NASA Astrophysics Data System (ADS)

Field-driven domain wall (DW) propagation in ferromagnetic nanotubes displays unusual effects, as revealed by a micromagnetic study. The left-right symmetry of the DW dynamics is broken, yielding markedly different DW mobilities for opposite propagation directions. This asymmetry arises from the tubular geometry and its impact on the DW structure. Also, the Walker breakdown field and velocity are found to be asymmetric for opposite directions. In certain cases, the breakdown can even be suppressed in one or both directions. Topological constraint requires a vortex-antivortex pair mediated breakdown, contrary to the single (anti)vortex in flat strips. This results in a higher breakdown velocity.

Yan, Ming; Andreas, Christian; Kákay, Attila; García-Sánchez, Felipe; Hertel, Riccardo

2012-06-01

231

Two lines of Walker carcinoma 256: their peculiarities and different interactions with the host.  

PubMed

Two sublines of Walker 256 carcinoma have been characterized for their ability to metastasize and to induce cachexia. The invasive, metastasizing line A induced terminal anorexia in rats with a mean survival time of 27 +/- 1.5 days. The non-invasive line B induced early anorexia and cachexia with a mean survival time of only 15 +/- 1 days. At death, the line B tumor was still smaller than the line A one, and no metastases were detectable. These two sublines are discussed as a composite model for studying anorexia and cachexia together with invasion and metastasis. PMID:6836744

Guaitani, A; Della Torre, P; Morasca, L; Pintus, C; Bartosek, I

1983-02-28

232

Walker carcinoma 256: a model for studies on tumor-induced anorexia and cachexia.  

PubMed

Data on anorexia and cachexia induced by Walker carcinoma 256 in Sprague-Dawley rats were analyzed in order to standardize an experimental model using a statistical (nondeterministical) procedure for assessing the efficacy of potential orexigenic agents. This model was characterized by a mean survival time of 14 +/- 1 days and by food intake and body weight loss starting from day 6 after tumor implantation. The complex course of cachexia was characterized by reduction in the weight of gastrocnemius muscle and epididymal adipose tissue, taken as representative sites of loss of proteins and lipids. PMID:6952138

Guaitani, A; Recchia, M; Carli, M; Rocchetti, M; Bartosek, I; Garattini, S

1982-01-01

233

Novel cyclovirus discovered in the Florida woods cockroach Eurycotis floridana (Walker).  

PubMed

A novel cyclovirus (proposed genus "Cyclovirus", family Circoviridae) was discovered in a specimen of Eurycotis floridana (Walker), also known as the Florida woods cockroach or palmetto bug, collected from Tarpon Springs, Florida. The Florida woods cockroach-associated cyclovirus GS140 (FWCasCyV-GS140) was obtained through a degenerate PCR assay and showed 64 % genome-wide pairwise identity to a cyclovirus identified in bat feces. This finding supports recent reports suggesting that Circoviridae members, traditionally thought to only infect vertebrates, are present within insect populations. PMID:23358613

Padilla-Rodriguez, Marco; Rosario, Karyna; Breitbart, Mya

2013-01-29

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

WHEN MACHINE DISCIPLINE AND POPULAR DISCONTENT DO (OR DO NOT ) CHANGE INSTITUTIONS IN THE VEBLENIAN PERSPECTIVE: AN INTEGRATION OF WALKER'S INTERPRETATION By  

Microsoft Academic Search

The present paper is an extension of Donald Walker's thesis on the Veblenian process of institutional evolution. In his Thorstein Veblen's Economic System of 1977 Walker stresses that the greater the workers' contact with machine discipline the higher their critical attitude towards the status quo ; moreover, this contact is satisfactory for generating a mechanism of overthrowing the existing institutional

Andrea Pacella

236

Insights into distributed plate rates across the Walker Lane from GPS geodesy  

NASA Astrophysics Data System (ADS)

geodetic slip rates are observed to be approximately two times greater than late Pleistocene geologic slip rates across the southern Walker Lane. Using a dense GPS network, we compare the present-day crustal velocities to observed geologic slip rates in the region. We find that the Walker Lane is characterized by a smooth transition from westward extension in the Basin and Range to northwestward motion of the Sierra Nevada block. The GPS velocity field indicates that (1) plate parallel (N37°W) velocities define a velocity differential of 10.6 ± 0.5 mm/yr between the western Basin and Range and the Sierra Nevada block, (2) there is ~2 mm/yr of contemporary extension perpendicular to the normal faults of the Silver Peak-Lone Mountain extensional complex, and (3) most of the observed discrepancy in long- and short-term slip rates occurs across Owens Valley. We believe the discrepancy is due to distributed strain and underestimated geologic slip rates.

Lifton, Zachery M.; Newman, Andrew V.; Frankel, Kurt L.; Johnson, Christopher W.; Dixon, Timothy H.

2013-09-01

237

Baseline-dependent effect of noise-enhanced insoles on gait variability in healthy elderly walkers.  

PubMed

The purpose of this study was to determine whether providing subsensory stochastic-resonance mechanical vibration to the foot soles of elderly walkers could decrease gait variability. In a randomized double-blind controlled trial, 29 subjects engaged in treadmill walking while wearing sandals customized with three actuators capable of producing stochastic-resonance mechanical vibration embedded in each sole. For each subject, we determined a subsensory level of vibration stimulation. After a 5-min acclimation period of walking with the footwear, subjects were asked to walk on the treadmill for six trials, each 30s long. Trials were pair-wise random: in three trials, actuators provided subsensory vibration; in the other trials, they did not. Subjects wore reflective markers to track body motion. Stochastic-resonance mechanical stimulation exhibited baseline-dependent effects on spatial stride-to-stride variability in gait, slightly increasing variability in subjects with least baseline variability and providing greater reductions in variability for subjects with greater baseline variability (p<.001). Thus, applying stochastic-resonance mechanical vibrations on the plantar surface of the foot reduces gait variability for subjects with more variable gait. Stochastic-resonance mechanical vibrations may provide an effective intervention for preventing falls in healthy elderly walkers. PMID:22739049

Stephen, Damian G; Wilcox, Bethany J; Niemi, James B; Franz, Jason R; Franz, Jason; Kerrigan, Dr; Kerrigan, D Casey; D'Andrea, Susan E

2012-06-26

238

NetWalker: a contextual network analysis tool for functional genomics  

PubMed Central

Background Functional analyses of genomic data within the context of a priori biomolecular networks can give valuable mechanistic insights. However, such analyses are not a trivial task, owing to the complexity of biological networks and lack of computational methods for their effective integration with experimental data. Results We developed a software application suite, NetWalker, as a one-stop platform featuring a number of novel holistic (i.e. assesses the whole data distribution without requiring data cutoffs) data integration and analysis methods for network-based comparative interpretations of genome-scale data. The central analysis components, NetWalk and FunWalk, are novel random walk-based network analysis methods that provide unique analysis capabilities to assess the entire data distributions together with network connectivity to prioritize molecular and functional networks, respectively, most highlighted in the supplied data. Extensive inter-operability between the analysis components and with external applications, including R, adds to the flexibility of data analyses. Here, we present a detailed computational analysis of our microarray gene expression data from MCF7 cells treated with lethal and sublethal doses of doxorubicin. Conclusion NetWalker, a detailed step-by-step tutorial containing the analyses presented in this paper and a manual are available at the web site http://netwalkersuite.org.

2012-01-01

239

Functional Schroedinger picture of a scalar field in a flat Robertson-Walker spacetime  

SciTech Connect

The author studies free and self-interacting quantum field theories of a scalar field in the functional Schroedinger picture. He establishes the renormalizability of the Gaussian wavefunctional approximation to a time-dependent variational principle, both for the Minkowski and the flat Robertson-Walker spacetime. The renormalizability depends upon the specific initial state and reasonable criteria for limiting the initial conditions is discussed. For those initial states that satisfy these criteria, it is shown that the time-dependent variational equations, in the Minkowski spacetime, are made finite by the renormalization prescription used in the vacuum sector. In order to study the dynamics of spacetime in the early universe, he computes a finite and renormalized energy-momentum tensor for both the free and the interacting theory (in the Gaussian approximation) in Robertson-Walker spacetime. Using the adiabatic expansion, he shows that the entire subtraction necessary to make the energy-momentum tensor finite in the free theory can be written in terms of covariantly conserved tensors. He further shows that the same subtraction is sufficient to make the energy-momentum tensor finite in the Gaussian approximation for the interacting theory provided that the mass and the coupling constants are renormalized. As a demonstration of the usefulness of this formalism, the problem of the onset of inflation in the early universe is discussed and a sample numerical computation is presented.

Samiullah, M.

1989-01-01

240

Heat balance and isotopic composition in the tropical tropopause layer (TTL) of a mock- walker circulation  

NASA Astrophysics Data System (ADS)

Cloud-resolving model simulations over a large-scale gradient in sea surface temperature (SST), dubbed a mock "Walker" circulation, connects the convection over warm SSTs to the subsiding flow over cooler SSTs and provides a framework for exploring the effects of tropical convection and the large-scale circulation on the TTL. The focus of the present work is on a series of simulations in this framework, performed using the System for Atmospheric Modeling (SAM, Khairoutdinov & Randall 2003) in two-dimensional domains with widths of up to 8192 km, horizontal grid sizes of 1-2 km, and vertical grid sizes of 300-400 m in the tropopause layer. A reverse circulation above the mock-Walker circulation in the troposphere is found, and its effect on the maintenance of the TTL is explored. In addition, simulations that include stable water isotopes (HDO and H218O) of water vapor and all hydrometeors (cloud water, cloud ice, rain, snow and graupel) and their microphysical interactions and fractionation are detailed. The roles of fast (convection) and slow (advection) processes in fixing the fractionation of water vapor in the TTL is explored.

Kuang, Z.; Blossey, P. N.; Romps, D. M.

2008-12-01

241

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

242

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

SciTech Connect

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

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

2007-01-01

243

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

NASA Astrophysics Data System (ADS)

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.EULEEJ0295-507510.1209/0295-5075/91/60006 91, 60006 (2010)].

Rambeau, Joachim; Schehr, Grégory

2011-06-01

244

Paleomagnetic Evaluation of Crustal-Scale Block Rotations in the Mina Deflection of the Central Walker Lane  

Microsoft Academic Search

Crustal deformation resulting from relative Pacific-North America plate motion is broadly distributed on faults across the western U.S.. Geodetic observations show that some 25 percent of transform plate motion is currently accommodated by faults east of the Sierra Nevada, from the eastern California shear zone to the central Walker Lane (CWL). The northwest trending faults of the CWL are joined

M. S. Petronis; J. W. Geissman; J. S. Oldow

2004-01-01

245

Redescription of two, often-confused Noctuid pests Copitarsia Decolora (Guenee) and C. Incommoda (Walker) (Lepidoptera: Noctuidae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Members of the genus Copitarsia Hampson (Noctuidae) are widespread pests of many agricultural commodities in Central and South America. Two species, C. incommoda (Walker) and C. turbata (Herrich-Schäffer), are of particular concern because they have been confused with each other in the literature an...

246

Nasopharyngeal teratoma ('hairy polyp'), Dandy-Walker malformation, diaphragmatic hernia, and other anomalies in a female infant.  

PubMed

Nasopharyngeal teratomas are rare and are infrequently associated with extra-oral malformations. The case of a premature female infant with multiple congenital anomalies, including nasopharyngeal teratoma, Dandy-Walker malformation, diaphragmatic hernia, and congenital heart defect, is presented. This constellation of malformations does not appear to have been reported previously. PMID:2074566

Aughton, D J; Sloan, C T; Milad, M P; Huang, T E; Michael, C; Harper, C

1990-12-01

247

Nasopharyngeal teratoma ('hairy polyp'), Dandy-Walker malformation, diaphragmatic hernia, and other anomalies in a female infant.  

PubMed Central

Nasopharyngeal teratomas are rare and are infrequently associated with extra-oral malformations. The case of a premature female infant with multiple congenital anomalies, including nasopharyngeal teratoma, Dandy-Walker malformation, diaphragmatic hernia, and congenital heart defect, is presented. This constellation of malformations does not appear to have been reported previously. Images

Aughton, D J; Sloan, C T; Milad, M P; Huang, T E; Michael, C; Harper, C

1990-01-01

248

Lymph node metastasis and cell movement: ultrastructural studies on the rat 13762 mammary carcinoma and Walker carcinoma.  

PubMed

The aim of this study was to determine whether tumor cells move actively through the linings of lymph node sinuses. Using 13762 carcinoma in F344 rats, and Walker carcinoma in Wistar rats, 20 X 10(6) tumor cells were injected into the footpad, and the ipsilateral popliteal lymph node examined by transmission electron microscopy. The same tumors were examined by making standard cell spots on plastic or glass surfaces, and examining these by phase and reflection contrast microscopy, fluorescent microscopy after anti-actin and phallacidin staining and transmission electron microscopy. The 13762 cells do not migrate through the lining of the lymph node sinusoid, nor move actively in vitro. Ultrastructural appearances of the Walker rat carcinoma cells suggest that they move actively through the sinus lining. After 24 h in vitro the Walker rat carcinoma cells in the centre of the spot are adherent to the surface. There is some movement of the edge of the sheet, and individual tumor cells at the edge of the sheet move actively and independently. We conclude that the Walker rat carcinoma invades the lining of the lymph node sinusoid by active cell movement, and the 13762 carcinoma does not. PMID:4042461

Carr, I; Levy, M; Orr, K; Bruni, J

249

Strategic Plan for Maggie L. Walker National Historic Site, Fiscal Years 2001-2005 (October 1, 2000-September 30, 2005).  

National Technical Information Service (NTIS)

This is the Strategic Plan for the Maggie L. Walker National Historic Site, a unit of the National Park System, administered by the National Park Service, U.S. Department of the Interior. The Plan includes the mission statement, derived from the legislati...

2005-01-01

250

Women Poets on the Left: Lola Ridge, Genevieve Taggard, Margaret Walker. Nancy Berke. Gainesville: UP of Florida, 2001  

Microsoft Academic Search

Nancy Berke offers a cogent and convincing argument to include radical women poets within the canonical texts of modernist poetry. Unlike the broad overview texts commonly used in academic settings, Berke's Women Poets on the Left places Lola Ridge, Genevieve Taggard, and Margaret Walker within the context of the political and social histories that shaped their lives and consciousness. This

C. S'Thembile West

2003-01-01

251

Optimization of pheromone dispenser density for managing the rice striped stem borer, Chilo suppressalis (Walker), by mating disruption  

Microsoft Academic Search

The rice striped stem borer, Chilo suppressalis (Walker) (Lepidoptera: Pyralidae) is one of the most important rice pests worldwide. Rice is frequently grown in an intensive production system in areas adjacent to environmentally sensitive areas. Therefore, the use of insecticides is problematic and new techniques, including mating disruption, are being introduced. Due to the high cost of pheromones, it is

C. Alfaro; V. Navarro-Llopis; J. Primo

2009-01-01

252

Effect of Rapid Cold Hardening on the Cold Tolerance of the Larvae of the Rice Stem Borer, Chilo suppressalis (Walker)  

Microsoft Academic Search

The effects of rapid cold hardening (RCH) on the cold tolerance of the last instar larvae of Chilo suppressalis (Walker) were evaluated for the first time. The discriminating temperature, induction, detection, duration and extent of RCH of the larvae in the laboratory were tested, and the supercooling points (SCPs) and the contents of water and lipid of the larvae after

Cheng-kui QIANG; Yu-zhou DU; Ling-ya YU; Ya-dong CUI; Fu-shan ZHENG; Ming-xing LU

2008-01-01

253

Recent state of stress change in the Walker Lane zone western Basin and Range province, United States  

Microsoft Academic Search

The NW to north-trending Walker Lane zone (WLZ) is located along the western boundary of the northern Basin and Range province with the Sierra Nevada. This zone is distinguished from the surrounding Basin and Range province on the basis of irregular topography and evidence for both normal and strike-slip Holocene faulting. Inversion of slip vectors from active faults, historic fault

Olivier Bellier; Mary Lou Zoback

1995-01-01

254

Impact of Favorite Stimuli Automatically Delivered on Step Responses of Persons with Multiple Disabilities during Their Use of Walker Devices  

ERIC Educational Resources Information Center

|Favorite stimuli were automatically delivered contingent on the performance of steps by two persons (a boy and a woman) with multiple disabilities during their use of support walker devices. The study lasted about 4 months and was carried out according to a multiple baseline design across participants. Recording concerned the participants'…

Lancioni, Giulio E.; Singh, Nirbhay N.; O'Reilly, Mark F.; Campodonico, Francesca; Piazzolla, Giorgia; Scalini, Lorenza; Oliva, Doretta

2005-01-01

255

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

Microsoft Academic Search

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

Qi-Liang Mao-Ying; Jun Zhao; Zhi-Qiang Dong; Jun Wang; Jin Yu; Min-Fen Yan; Yu-Qiu Zhang; Gen-Cheng Wu; Yan-Qing Wang

2006-01-01

256

Plant-Growth Response to Various Combinations of Mulches and Spoil Substrates on a Walker County, Alabama, Surface Coal Mine.  

National Technical Information Service (NTIS)

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, pin...

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

1982-01-01

257

Defoliation and growth loss in young Sitka spruce following repeated attack by the green spruce aphid, Elatobium abietinum (Walker)  

Microsoft Academic Search

Green spruce aphid, Elatobium abietinum (Walker), is a serious defoliator of Sitka spruce (Picea sitchensis (Bong.) Carr.). In a field experiment in Hafren Forest, mid-Wales, different population densities of E. abietinum were created amongst plots of P91 Sitka spruce by applying insecticides and artificially infesting trees with aphids. Trees subjected to high aphid populations (HP treatment) lost 51, 29 and

N. A. Straw; N. J. Fielding; G. Green; J. Price

2005-01-01

258

Acclimation in Simulated Lake Water Increases Survival of Lahontan Cutthroat Trout Challenged with Saline, Alkaline Water from Walker Lake, Nevada  

Microsoft Academic Search

We investigated the effect of acclimation and condition factor (K) on short-term survival of subyearling Lahontan cutthroat trout Oncorhynchus clarkii henshawi reared at Lahontan National Fish Hatchery, Gardnerville, Nevada, and challenged for 1 week with saline, alkaline water from Walker Lake, Nevada. The effect of acclimation and lake-water challenge on plasma osmolality was also investigated. Fish were acclimated for 0,

John P. Bigelow; Wendy M. Rauw; Luis Gomez-Raya

2010-01-01

259

Perception and reality of conflict: walkers and mountain bikes on the Queen Charlotte Track in New Zealand  

Microsoft Academic Search

A variety of social and physical impacts are attributed to mountain biking. In many cases, the perception of these impacts differs from the reality of on-site experiences. This distinction is explored in two ways. First, a brief review of impact issues associated with mountain bikes is carried out. Second, results are presented from a survey of 370 walkers on a

Gordon Cessford

2003-01-01

260

Cosmological redshift in Friedmann-Robertson-Walker metrics with constant space-time curvature  

NASA Astrophysics Data System (ADS)

Cosmological redshift z grows as the Universe expands and is conventionally viewed as a third form of redshift, beyond the more traditional Doppler and gravitational effects seen in other applications of general relativity. In this paper, we examine the origin of redshift in the Friedmann-Robertson-Walker (FRW) metrics with constant space-time curvature, and show that - at least for the static space-times - the interpretation of z as due to the 'stretching' of space is coordinate dependent. Namely, we prove that redshift may also be calculated solely from the effects of kinematics and gravitational acceleration. This suggests that its dependence on the expansion factor is simply a manifestation of the high degree of symmetry in FRW, and ought not be viewed as evidence in support of the idea that space itself is expanding.

Melia, Fulvio

2012-05-01

261

Unbiased expectation values from diffusion quantum Monte Carlo simulations with a fixed number of walkers  

NASA Astrophysics Data System (ADS)

We append forward walking to a diffusion Monte Carlo algorithm which maintains a fixed number of walkers. This removes the importance sampling bias of expectation values of operators which do not commute with the Hamiltonian. We demonstrate the effectiveness of this approach by employing three importance sampling functions for the hydrogen atom ground state, two very crude. We estimate moments of the electron-nuclear distance, static polarizabilities, and high-order hyperpolarizabilites up to the fourth power in the electric field, where no use is made of the finite field approximation. The results agree with the analytical values, with a statistical error which increases substantially with decreasing overlap of the guiding function with the exact wave function.

Bosá, Ivana; Rothstein, Stuart M.

2004-09-01

262

The doctor and the "delta factor": Walker Percy and the dilemma of modern medicine.  

PubMed

As medical science progresses, a tension has developed between the art of medicine, which deals with patients as individual persons, and the science itself, which focuses on the objective pathology. This tension is furthered as medicine identifies itself increasingly with science. To explore the consequences of this unbalanced identification, and the strain it places on the physician-patient relationship, this article examines the thought of Walker Percy, and in particular his novel The Second Coming. In this novel, Percy, a physician by training, presents a case of a patient suffering at the hands of medicine-turned-reductionist. The novel highlights the breakdown of communication between physician and patient within modern medicine, and raises important questions about how to best understand, and thereby preserve, medicine's true art. PMID:12388889

Majeres, Kevin D

2002-01-01

263

Efficient malignant transformation of rat embryo fibroblasts by genomic DNA from Walker carcinoma cells.  

PubMed

DNA isolated from Walker carcinoma ascites cells was transfected into primary rat embryo fibroblasts (REF), selecting transformed cells by growth in soft agar after prolonged propagation in monolayer. Both high molecular weight genomic DNA and a partially purified mitochondrial DNA fraction were able to transform REF with high efficiency, whereas pure mitochondrial DNA failed to elicit a transformed phenotype. Hybridization experiments showed that the mitochondrial DNA fraction contained DNA species of presumably extramitochondrial origin. Colonies were cloned into morphologically transformed, foci-forming, immortalized cell lines, showing different degrees of chromosomal alterations, tumorigenicity, and production of cell growth factors. These results indicate that although REF are refractory to genomic neoplastic DNA or to single cloned oncogenes in the absence of enhancers, they can be efficiently transformed by chromosomal DNA from a highly malignant tumor under conditions selecting against the remaining normal cells. PMID:3389748

Arvelo, F; Perez, J L; Antuna, O; Gonzalez-Cadavid, N F

264

First-trimester sonographic findings associated with a dandy-walker malformation and inferior vermian hypoplasia.  

PubMed

We report 2 cases in which first-trimester measurements of the intracranial translucency and the brain stem-to-occipital bone diameter were markedly enlarged. This finding was thought to represent an abnormal fourth ventricle-cisterna magna complex. Subsequently, the diagnoses of a Dandy-Walker malformation with partial vermian agenesis in 1 case and inferior vermian hypoplasia in the other were established and confirmed by either postmortem autopsy or postnatal magnetic resonance imaging. These cases suggest that evaluation of the fourth ventricle-cisterna magna complex, by measuring the intracranial translucency or brain stem-to-occipital bone diameter may identify some cases with structural malformations of the cerebellum as early as the first trimester. PMID:24065268

Bornstein, Eran; Rodríguez, José Luis Goncalves; Pavón, Erika Carolina Álvarez; Quiroga, Héctor; Or, Drorit; Divon, Michael Y

2013-10-01

265

Effects of subcutaneously implanted sustained-release cyclophosphamide capsules on Walker 256 solid rat tumor.  

PubMed

Complete regression of Walker 256 solid rat tumor was brought about by the subcutaneous implantation of a single sustained-release cyclophosphamide capsule adjacent to the tumor mass. Untreated control animals died within 3 weeks after receiving the tumor with large necrotic masses. Rats with sustained-release capsules experienced complete tumor regression within 28 days. Upon examination, the tissues around the previous tumor mass has regenerated, and no viable tumor cells could be found in the area where the previous tumor mass was. Around the implanted sustained-release cyclophosphamide capsule a fibrous sheath has developed over the 3 weeks it was in situ. This study suggests an alternate means of cytoxic drug administration in the treatment of solid tumors in experimental animals. PMID:875393

Fu, J C; Moyer, D L; Cuevas, J; Young, R; Elshire, D

1977-01-01

266

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.

He, Yu; Liu, David R.

2010-01-01

267

Ascending transaqueductal cystoventriculoperitoneal shunting in dandy-walker malformation: technical note.  

PubMed

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

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

2013-08-13

268

Changes in the Walker and Hadley circulations associated with the Southern Annular Mode  

NASA Astrophysics Data System (ADS)

Extratropical impacts on tropical climates are one of the most exciting areas of meteorological investigation in recent times. The present study elucidates the seasonal impact of the Southern Annular Mode (SAM) on predominant tropical circulations such as Hadley and Walker. The velocity potential at 200 hPa is used to understand the spatio-temporal variability in tropical circulations in the boreal summer and winter seasons. The results show an intensification of seasonal velocity potential in the composite of the low phase of the SAM. The seasonal climatological values of velocity potential observed for the period from 1979 to 2012 are of lesser magnitudes than earlier findings. The convergence/divergence locations of tropical circulation have shifted from their mean positions in the alternative phase of the SAM. The low-level convergence in the southern hemispheric Hadley circulation (HC) is enhanced in the composite of the positive phase of the SAM; however, the SAM's effect on the HC is no stronger in the summer. Another interesting feature noted in the present study is the weakening of the Walker circulation associated with the positive phase of the SAM, which can influence the basic state of the tropical Pacific Ocean. The SAM's interannual variability exhibits a significant positive trend in winter. The study reveals that the positive phase of the SAM could be a possible explanation for the recent changes in the tropical circulation patterns; however, the variability in tropical circulation anomalies associated with the SAM should be noted on seasonal and monthly scales to understand the dynamical mechanism behind the relationship. The impact of the SAM on tropical circulation may continue in future decades, as this southern extratropical vacillation is predicted to remain in a positive phase due to the increase in greenhouse gases and the variability in ozone.

Viswambharan, Nithin; Mohanakumar, K.

2013-10-01

269

Studies on the population kinetics of the Walker carcinoma by autoradiography and pulse cytophotometry.  

PubMed

The proliferation parameters of the Walker carcinoma were estimated from both in vivo and in vitro measurements. tthe transplantable Walker carcinoma 256 was grown in male inbred BD1 rats. During exponential growth, 5--6 days after transplantation, a PLM curve was performed, yielding estimates of TC approximately equal to 18-0 hr, TS approximately equal to 6-4 hr, TG2+M approximately equal to 4-1 hr. With the double labelling technique in vitro under 2-2 atm oxygen we obtained: TC approximately equal to 18-2 hr, TS approximately equal to 8-2 hr, TG2+M approximately equal to 2-0 hr. From pulse cytophotometry DNA content histograms the fractions of cells in the cell cycle phases were calculated using a computer program: fG1 approximately equal to (47-6 +/- 1-1)%, fS approximately equal to (34-1 +/- 1-0)%, fG2+M approximately equal to (18-3 +/- 1-5)%. These fractions remained constant between the fifth and the twelfth day after transplantation. At that time the tumour growth had already slowed down appreciably. The growth fraction determined by repetitive labelling was 0.96 on the fifth and 0-93 on the seventh and eleventh day. The cell loss factor was phi approximately equal to 17% during exponential tumor growth and increased to about 100% between the tenth and twelfth day. The agreement of the cell kinetic data determined by autoradiography from solid tumours in vivo (PLM, continuous labelling) and autoradiography as well as pulse cytophotometry from in vitro experiments (excised material) was satisfactory. PMID:326411

Erbe, W; Linden, W A; Reddy, S B; Zywietz, F; Baisch, H

1977-05-01

270

Binding of formyl peptides to Walker 256 carcinosarcoma cells and the chemotactic response of these cells  

SciTech Connect

N-Formylmethionylleucylphenylalanine (fMLP) induces chemotaxis in leukocytes, the response being mediated by peptide binding to a receptor on the plasma membrane. In tumor cells, this peptide has been reported to induce cellular swelling and chemotaxis in vitro and to enhance the localization of circulating tumor cells in vivo. In the Boyden chamber, the authors evaluated the migratory responses of Walker carcinosarcoma 256 cells to varying concentrations of fMLP. Sigmoidal dose-response curves were obtained with the dose of chemotactic factor that elicits a half-maximal chemotactic response of 5.0 +/- 2.5 X 10(-8) M. Checkerboard analysis indicated that these responses were dependent upon a concentration gradient of fMLP with increases in migration of circa 2 to 2.5 times that of random movement. To examine the binding of fMLP, the tumor cells were incubated with 5 X 10(-9) M fML-(/sup 3/H)P in Hanks balanced salt solution. Specific binding (0.5 to 1% of total radioligand, to whole cells inhibited by 5 X 10(-6) M fMLP) approached equilibrium after 4 to 6 h at 4 degrees C and after 6 to 10 h at 22 degrees C. Autoradiographic studies demonstrated heterogeneous binding of the peptide by tumor cells and also showed its intracellular localization. In homogenates of Walker cells prepared in 0.1 M Tris HCl, pH 7.4, with 10 mM MgCl2 and bovine serum albumin (1 mg/ml), specific binding of approximately 0.5% of total fML-(/sup 3/H)P reached equilibrium after 60 min at 4 degrees C. In whole cells and homogenates, binding was reversible by addition of unlabeled fMLP.

Rayner, D.C.; Orr, F.W.; Shiu, R.P.

1985-05-01

271

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

SciTech Connect

Samples of recent sediments, representing up to 1,000 years of accumulation, were collected from three closed basin lakes to assess the effects of brine composition on the accumulation of 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{sub 4} brine with low alkalinity. Algal debris is entrained in the high density (1.132-1.190 g/ml) 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. Mono Lake is an alkaline (Na-CO{sub 3}-Cl-SO{sub 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. 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 of humic substances and dissolved organic carbon provide information on the source of the recent sedimentary organic carbon, its relative state of decomposition, and its chemical structure. 44 refs., 10 figs., 6 tabs.

Domagalski, J.L.; Orem, W.H.; Eugster, H.P.

1989-01-01

272

Spatially Flat Robertson-Walker Cosmology with Mixed Radiation and Thermalized Massless Scalar Field Content  

NASA Astrophysics Data System (ADS)

Basically, in this paper our interest has been focused on the following problem: how did the thermalization of the minimally coupled mass-less scalar field go in the early radiation dominated spatially flat Robertson-Walker Universe and what kind of cosmological consequences did it have by its back-reaction effect? Therefore, we have worked out explicitly the exact frequency modes, quantized the massless field on the (k = 0)-radiation dominated background and, finally, have estimated the many-particle expectation value of the conservative energy-momentum tensor, assuming a Bose-Einstein distribution (at the radiation equilibrium temperature) of the quanta. Unlike the Minkowskian case, when w = 3p for the massless scalar source, this time, we get equal supplementary contributions to the pressure and the energy-density of the thermalized field. They mainly come from the decaying amplitude of the exact frequency modes and principially, strongly influence the evolution of the mixed radiation and thernalized massless scalar field dominated (k = 0)-Robertson-Walker Universe by the back reaction effect. It arises a maximal, Planckian-like, critical tenperature and the mixed matter Universe smoothly goes from the phase of the coherent massless scalar field domination, when a ~t^(1/3) and the deceleration parameter q = 2, to the usual phase of radiation a ~t^(1/2) and q = 1. The exact solution of Einstein equations over the whole of this transition has been concretely estimated in closed form as well as the "luminosity-distance versus cosmological red-shift" relation that fully characterizes the model.

Dariescu, Ciprian; Hamamoto, Shinji

273

Prenatal diagnosis and molecular characterization of a novel locus for Dandy-Walker malformation on chromosome 7p21.3.  

PubMed

We present three foetuses with Dandy-Walker malformation, intra-uterine growth restriction and multiple congenital abnormalities, who were studied by array-based comparative genomic hybridization and revealed a novel locus on chromosome 7p21.3. The association of pure chromosome 7p aberrations with Dandy-Walker malformation has rarely been reported. The present study suggests that the critical region associated with Dandy-Walker malformation is restricted to 7p21.3, including the cerebellar disease associated genes NDUFA4 and PHF14. PMID:22617776

Liao, Can; Fu, Fang; Li, Ru; Yang, Xin; Xu, Qing; Li, Dong-Zhi

2012-05-19

274

Comparison of geologically-averaged paleomagnetic and "instantaneous" GPS rotation data in the West-Central Walker Lane  

NASA Astrophysics Data System (ADS)

The Walker Lane belt is a highly tectonically active region of dextral shear in western North America. Situated between the margins of the Sierra Nevada microplate and the Basin and Range extension, it extends northward from the Garlock Fault into portions of Southern Oregon. The Walker Lane is characterized by dextral shear accommodated by strike slip faults and left-stepping normal faults (Unruh et al, 2003). Faulting in the Walker Lane accounts for approximately 25% of the relative motion between the North American and Pacific Plates (Reheis and Dixon 1996). The study spans a region where the Sierra Nevada microplate has shed fault-bounded blocks from its eastern margin into the central Walker Lane during the Neogene. These blocks have behaved somewhat independently of one another and the Sierra Nevada as evidenced by spatially-variable magnitudes of vertical-axis rotation. This blurs the boundary of definition between microplate and fault block. One of the key questions regarding Walker Lane deformation is what is the role of rotation with respect to fault blocks and at what rate(s) does rotation occur. The software package SSPX (Cardozo and Allmendinger 2009) is used to examine previously published geodetic data to derive rotation rates in the west-central Walker Lane. A rate of 1.70° ± 0.24°/Ma is determined for Bridgeport Valley, CA based upon strain inversion of the locally-sparse GPS station data in SSPX. This rate is consistent with paleomagnetically-determined rotation rates for ~9.4 Ma members of the Stanislaus Group around Bridgeport Valley, adjacent to the Mina Deflection (e.g. King et al, 2007 and our data). However there are several shortcomings to using currently available GPS data for this purpose. GPS station spacing in many places does not provide spatial resolution of rotation comparable to the paleomagnetic dataset, which in turn limits our ability to examine small lithospheric fault blocks geodetically. The paleomagnetic data shows rotation variations on the scale of <5 km. Thus, due to GPS station spacing, our strain inversion reveals a spatially-averaged rotation for a larger given area and is not able to detect small lithospheric blocks or groups of blocks with anomalously large rotation rates of 7°/Ma or higher. An alternative hypothesis is that rotation rate is variable with time and that large rotations occurred and have slowed or stopped.

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

2011-12-01

275

Bax\\/Bcl2 Protein Expression Ratio and Leukocyte Function Are Related to Reduction of Walker256 Tumor Growth After ?-Hydroxy-?-Methylbutyrate (HMB) Administration in Wistar Rats  

Microsoft Academic Search

This study investigated the mechanisms by which ?-hydroxy-?-methylbutyrate (HMB) administration in rats reduces Walker-256 tumor growth. Male Wistar rats were supplemented with HMB (76 mg\\/kg\\/day) (HW), or a placebo (W), during 8 wk by gavage. At the 6th wk, rats were inoculated with a suspension of Walker 256 tumor cells (3 × 10\\/mL). Fifteen days after inoculation, the HW group

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

2012-01-01

276

Crustal Deformation of the Central Walker Lane from GPS velocities: Block Rotations and Slip Rates  

NASA Astrophysics Data System (ADS)

The Walker Lane is a complex zone of active intracontinental transtension between the Sierra Nevada/Great Valley (SNGV) microplate and the Basin and Range in the western United States. Collectively, this ~100 km wide zone accommodates ~20% of the Pacific-North American relative plate motion. The Central Walker Lane (CWL) extends from the southern boundary of the Mina Deflection (~38.0°N) to the latitude of Lake Tahoe (~39.5°N) and encompasses the transition from Basin and Range style faulting in the east to the stable block motion of the SNGV microplate in the West. We combine GPS data from the Mobile Array of GPS for Nevada Transtension (MAGNET, http://geodesy.unr.edu/networks) with continuous observations from the EarthScope Plate Boundary Observatory to solve for rates of crustal deformation in the CWL through a block modeling approach. The GPS coordinate time series are derived in this region as part of a 7000-station global network solution using the latest JPL reanalysis of GPS orbits, and the latest antenna models for stations and satellites. The data were processed by precise point positioning using JPL's GIPSY OASIS II software followed by our custom Ambizap3 software, to produce a globally-consistent, ambiguity-resolved network solution. GPS time series in the western United States are rotated into a North America-fixed reference frame and are spatially filtered with respect to the secular motions of reference stations that demonstrate long-term secular stability. In the study region, we use 130 GPS velocities that are corrected for viscoelastic postseismic relaxation following 19th and 20th century earthquakes in the Central Nevada Seismic Belt to constrain rates of long-term fault slip and block rotation. The spatial density and precision of our velocity field (average station spacing of ~20 km with uncertainties well below 1 mm/yr) allow us to compare geodetically estimated slip rates with geologic observations as well as address specific questions about how shear is transferred from the Southern Walker Lane through the Mina Deflection and evaluate along-strike variation of the slip rate on the Sierra Nevada range front fault. Preliminary results confirm a pattern of deformation consistent with geological observations. Deformation zones are characterized by 1) left-lateral slip on east-northeast trending faults and clockwise block rotations in the Mina Deflection, 2) right-lateral slip on northwest trending faults along the eastern margin of the CWL, 3) east-west extension along north trending faults in the western portion of the CWL with right lateral slip increasing toward the SNGV microplate boundary, 4) clockwise rotation of blocks in the Carson Domain, and 5) northwest directed extension in the Basin and Range. Estimates of fault slip rates along the eastern boundary of the SNGV block find that slip is oblique with preliminary rates ranging between 0.4-0.8(±0.1) mm/yr horizontal extension and 0.9-1.5(±0.1) mm/yr right lateral.

Bormann, J. M.; Hammond, W. C.; Kreemer, C. W.; Blewitt, G.; Wesnousky, S. G.

2010-12-01

277

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

278

Late Pleistocene displacement and slip rate for the Breckenridge fault, Walker Basin, southern Sierra Nevada, California  

NASA Astrophysics Data System (ADS)

The north-striking Breckenridge fault occurs along the 11-km-long western margin of Walker Basin, a west-tilted intermontane alluvial basin in the southern Sierra Nevada. This east-dipping normal fault has prominent geomorphic expression in the form of east-facing fault scarps on alluvial-fan deposits and distinct triangular facets of granitic bedrock along the range front. Steep, east-draining valleys are incised into bedrock west of the fault and are associated with inset or overlapping alluvial fan surfaces east of the fault. Detailed analysis of lidar-derived digital elevation models (DEMs) and field geomorphic mapping suggest that a 2-km-wide series of small right-stepovers separate the Breckenridge fault from the Holocene-active Kern Canyon fault to the north. Directly south of Walker Basin, prominent geomorphic expression of the Breckenridge fault dies out in an area of complex and distributed microseismicity, suggesting that the fault does not connect with the active White Wolf fault to the south. Herein, on the basis of geologic and geomorphic mapping, DEM interpretation, and cosmogenic radionuclide (CRN) dating, we report the first documented evidence for late Pleistocene normal faulting on the Breckenridge fault. At the Oak Tree site (38.431N, 118.545W), two alluvial-fan deposits (Qf1 and Qf3) exhibit east-down normal fault displacement. The active channel is entrenched about 8 and 14 m below these abandoned surfaces. Topographic profiles generated from DEMs along the extensive Qf1 and Qf3 surfaces show that fault scarp heights are progressively lower on younger surfaces. The oldest surface (Qf1) shows vertical separation of ~7 m, and the intermediate Qf3 surface exhibits ~4 m of vertical separation. The next youngest surface (Qf4) appears undeformed across the fault trace. Samples from granitic boulders exposed on the Qf1, Qf3, and Qf4 surfaces were collected for 10Be exposure dating. The CRN dates are consistent with stratigraphic position and yield ages (assuming zero inheritance and no erosion) of 68 ± 7 ka (1 sigma, n=3) for Qf1, 35 ± 2 ka (1 sigma, n=3) for Qf3, and 12 ± 2 ka (1 sigma, n=3) for Qf4. Using measured vertical separations, these data provide preliminary average late Pleistocene slip rates for the Breckenridge fault of ~0.1 mm/yr over ~68 and ~35 ky timescales. These data permit a relatively constant slip rate for the late Pleistocene on the Breckenridge fault that is lower than the Kern Canyon fault to the north. In addition, the 12 ± 2 ka age of the apparently undeformed Qf4 surface constrains the minimum age for the most-recent surface deformation and is consistent with the absence of fault scarps across young alluvial fan surfaces along most of the range front. These ages confirm previous analyses suggesting that the Breckenridge fault has controlled Quaternary deposition in the Walker Basin, and shows that the east-down normal displacement has continued to at least 35 ka and possibly 12 ka.

Brossy, C. C.; Baldwin, J. N.; Kelson, K. I.; Rood, D. H.; Kozlowicz, B.; Simpson, D.; Ticci, M.; Amos, C. B.; Kozaci, O.; Lutz, A.

2010-12-01

279

New approach to the adoptive immunotherapy of Walker-256 carcinosarcoma with activated macrophages combined with photodynamic therapy.  

PubMed

Experiments were performed on five batches of Wistar inbred rats with Walker-256 carcinoma receiving sole (PDT, MAK) or combined therapy (PDT + MAK-A; PDT + MAK-B); the control batch (HBSS) consisted of animals with untreated tumors. The results were as follows: a) the sole treatment (PDT, MAK) gave survival rates between 37.7 and 47.5%, b) the "combined" therapy in five doses increased significantly (70.8%) the survival rate of tumor bearing rate as well as the rate of complete regression (82.1%). The cell-mediated immunity test and histopathological as well as the electron microscopy observations were in full agreement with the results above. Summing up, these results demonstrate that "combined" photodynamic therapy with intra- and peritumoral MAK infusion stimulated cell-mediated antitumoral activity, increased survival rates and reduces incidence of Walker-256 carcinoma in rat model. PMID:12165976

Dima, V F; Ionescu, M D; Balotescu, C; Dima, S V; Vasiliu, V; Lacky, D

280

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

281

Lamé equation for the distance redshift in a partially filled beam Friedmann-Lemaître-Robertson-Walker cosmology  

Microsoft Academic Search

The differential equation governing the distance redshift for partially filled-beam optics in pressure-free Friedmann-Lemaître-Robertson-Walker (FLRW) cosmology is shown to be the Lamé equation. The distance redshift D(z) discussed is appropriate for observations in inhomogeneous cosmologies for which lensing by masses external to the observing beam is negligible and for which lensing by transparent matter within the beam can be approximated

R. Kantowski

2003-01-01

282

Automatically Delivered Stimulation for Walker-Assisted Step Responses: Measuring its Effects in Persons with Multiple Disabilities  

Microsoft Academic Search

The present two studies evaluated the effects of automatically delivered stimulation for walker-assisted step responses with\\u000a four persons with multiple disabilities. In Study I, the participants (two children) wore two optic sensors at their heels,\\u000a which were activated by the performance of steps. Each sensor activation produced a 2.5-s stimulation during the intervention\\u000a and post-intervention periods. In Study II, the

Giulio E. Lancioni; Nirbhay N. Singh; Mark F. O’Reilly; Jeff Sigafoos; Doretta Oliva; Giorgia Piazzolla; Sara Pidala; Angela Smaldone; Francesco Manfredi

2007-01-01

283

Gaussian approximation of lambdaphi/sup 4/ theory in (3+1)-dimensional spatially flat Robertson-Walker space  

SciTech Connect

We investigate lambdaphi/sup 4/ theory within the Gaussian approximation in spatially flat Robertson-Walker space in 3+1 dimensions. After having performed an adiabatic expansion for one of the ansatz functions, we find that the renormalization of the energy-momentum tensor provides two additional constraints which have to be satisfied by the bare couplings. These conditions force the theory to be trivial after renormalization.

Pohle, H.

1989-03-15

284

Circadian variations in 32P uptake of a DMBA-induced mammary tumour and Walker carcinosarcoma in rats  

Microsoft Academic Search

The 32P uptake in a mammary tumour induced by DMBA and in the Walker 256 carcinosarcoma was measured by external GM -tubes. The uptake was significantly higher than in the skin. During exposure to a synchronized light regime a circadian variation was present in the 32P uptake of the hormone-dependent DMBA-induced tumour. The maximal 32P uptake was in the dark

U Møller; J Bojsen

1976-01-01

285

Característiques de les poblacions larvaries hivernants de Chilo Suppressalis Walker al delta de l'Ebre (Lepidoptera: Crambidae)  

Microsoft Academic Search

Un aspecte interessant i, probablement, un dels menys coneguts del cicle biològic de Chilo suppressalis<\\/i> Walker és la capacitat que tenen algunes formes larvàries per fer front a l'hivern.
\\u000aEl present estudi, dut a terme a la zona arrossera del Delta de l'Ebre, s'ha centrat en la caracterització de les larves de C. Suppressalis<\\/i>, comparant les que es troben en

Joan Ramoneda i Molins; Jordi Roig i Revert

1999-01-01

286

The development of quantitative occurrence prediction of infestation by the rice stem-borer, Chilo suppressalis Walker , in Japan  

Microsoft Academic Search

The new method was developed with the objective to meet the universal demand for the prediction of the abundance of the rice\\u000a stem-borer,Chilo suppressalis\\u000a Walker, after 30 years’ pending state. The degrees of infestation were assessed by the sequential sampling test under the prevailing\\u000a three categories, low, moderate and high in terms of percentage infested rice hills. The numerical table

T. Torii

1971-01-01

287

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

Microsoft Academic Search

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 require- ment for these motifs in interactions with XRCC2 and RAD51C, and for survival of cells in response to DNA interstrand crosslinks (ICLs). Ectopic expression of

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

2006-01-01

288

ASSOCIATION OF SEVERE AUTOSOMAL RECESSIVE OSTEOPETROSIS AND DANDY-WALKER SYNDROME WITH AGENESIS OF THE CORPUS CALLOSUM  

Microsoft Academic Search

A severe form of autosomal recessive osteopetrosis associated with Dandy-Walker syndrome and agene- sis of the corpus callosum is reported in a full-term boy born to consanguineous parents. The diagnosis was made shortly after birth. Clinical features were cranio-facial dysmorphy, macrocephaly, hepato- splenomegaly, severe anemia and thrombocytopenia. Skeletal radiographs revealed generalized increase in bone density and abnormal metaphyseal remodeling. Cranial

H. BEN HAMOUDA; M. N. SFAR; R. BRAHAM; M. BEN SALAH; A. AYADI; H. SOUA; H. HAMZA; M. T. SFAR

2001-01-01

289

Enzymatic properties of ?-amylase in the midgut and the salivary glands of mulberry moth, Glyphodes  pyloalis Walker (Lepidoptera: Pyralidae)  

Microsoft Academic Search

The pyralid moth, Glyphode pyloalis Walker, is an important pest of the mulberry. Amylases are the hydrolytic enzymes that catalyze the hydrolysis of the ?-D-(1,4)-glucan linkage in glycogen and other related carbohydrates. Laboratory-reared fifth stadium larvae were randomly selected; the midgut (MG) and the salivary glands (SG) were removed by dissection under a dissecting microscope and ?-amylase activity was assayed using

Elham Yezdani; Jalal Jalali Sendi; Arash Zibaee; Mohammad Ghadamyari

2010-01-01

290

Failure of systemic ketosis to control cachexia and the growth rate of the Walker 256 carcinosarcoma in rats.  

PubMed Central

The Walker 256 carcinosarcoma was shown to lack the enzyme 3-ketoacid CoA transferase. This suggests that ketone bodies cannot be used as a major substrate for the energy metabolism of this tumour. Systemic ketosis (1-2 mM acetoacetate plus 3-hydroxybutyrate) was induced both in tumour-bearing and in non-tumour-bearing rats with a diet containing 70% medium chain triglyceride. However, in rats bearing the Walker 256 tumour, this dietary ketosis did not reduce the tumour growth rate nor did it prevent the subsequent decrease in host body weight. Host body nitrogen losses were similarly unaffected. The ketosis induced in tumour bearing rats was shown to be abnormal since the blood glucose concentration of ketotic, tumour-bearing rats was significantly higher compared with that of ketotic non-tumour bearing rats (5.2 +/- 0.4 mM cf 3.4 +/- 0.6 mM, P less than 0.01). These results may partly explain why systemic ketosis failed to alter the growth and cachexia induced by the Walker 256 carcinosarcoma.

Fearon, K. C.; Tisdale, M. J.; Preston, T.; Plumb, J. A.; Calman, K. C.

1985-01-01

291

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

PubMed Central

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

Olivier, Jake; Walter, Scott R.

2013-01-01

292

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

PubMed

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

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

2013-04-30

293

Distance-Redshift in Inhomogeneous ?0=1 Friedmann-Lemaître-Robertson-Walker Cosmology  

NASA Astrophysics Data System (ADS)

Distance-redshift relations are given in terms of associated Legendre functions for partially filled beam observations in spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) cosmologies. These models are dynamically pressure-free and flat FLRW on large scales but, because of mass inhomogeneities, differ in their optical properties. The partially filled beam area-redshift equation is a Lamé equation for arbitrary FLRW models and is shown to simplify to the associated Legendre equation for the spatially flat, i.e., ?0=1, case. We fit these new analytic Hubble curves to recent supernovae (SNe) data in an attempt to determine both the mass parameter ?m and the beam-filling parameter ?. We find that current data are inadequate for limiting ?. However, we are able to estimate what limits are possible when the number of observed SNe is increased by factor of 10 or 100, sample sizes achievable in the near future with the proposed SuperNova Acceleration Probe satellite.

Kantowski, R.; Thomas, R. C.

2001-11-01

294

Variability and symmetry of gait in early walkers with and without bilateral cerebral palsy  

PubMed Central

Purpose Investigating gait characteristics during the early stages of walking in CP may contribute to the understanding of the development of impaired gait. The objective of this study was to investigate differences in the variability and symmetry of spatiotemporal gait characteristics during the early years of walking in children with bilateral spastic CP compared to children with similar amounts of walking experience and typical development (TD). Methods The spatiotemporal gait parameters of 31 children (15 with spastic CP, 16 with TD) who had an average of 28.5 (18.1 SD) months of walking experience were collected using an instrumented walkway. Results All primary spatiotemporal parameters were reduced in the CP group, who also demonstrated greater stride-to-stride variability, compared to the TD group. There were no statistically significant differences in side-to-side symmetry between groups. Ankle dorsiflexion range of motion was related to several of the gait measures. Implications Clinical trials investigating gait interventions during the early years of walking in children with CP should be conducted to determine if treatment can reduce the functional limitations that are present during the emergence of walking skills. Further investigation should examine variability and symmetry in the kinematics, kinetics, and muscle activity patterns of early walkers with CP, and the effect of treatment on the variability and symmetry of walking characteristics.

Prosser, Laura A.; Lauer, Richard T.; VanSant, Ann F.; Barbe, Mary F.; Lee, Samuel C.K.

2010-01-01

295

Paramagnetic changes in cancer: growth of Walker 256 carcinoma studied in frozen and lyophilized tissues.  

PubMed Central

Samples of Walker 256 carcinoma grown in muscles of Sprague-Dawley rats were studied at low temperatures before and after lyophilization. The effects of lyophilization on the ESR spectra were different for tumours and normal muscle. Prior to lyophilization of a tumour sample, there was a decrease in free radicals, while after the lyophilization, there was an "increase". The "increase" was due to the lyophilized tumour having a narrower line, producing a greater peak-peak height measurement than in muscle, without an increase in the total number of spins. Exposure of lyophilized samples to air produced an increase in the intensity of the spectra and a change in line shape; also these effects differed for tumour and muscle. Mn++ levels were lower in tumour than in muscle, a difference eliminated by lyophilization. Poor growth conditions in tumours increased the occurrence of ESR spectra due to NO complexes with both heme and non-heme iron proteins. These results may help to resolve the principal controversies about experimental findings in ESR of tumours. At least part of the signals seen after lyophilization do not reflect free radicals in vivo. The signals after lyophilization reflect biochemical differences between tumour and muscle; spectroscopic data indicate that it is feasible to determine the molecular basis of these differences.

Gutierrez, P. L.; Swartz, H. M.

1979-01-01

296

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

SciTech Connect

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

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

1988-02-01

297

[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

298

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

299

[Dynamic changes of cold-resistant substances of overwintering Chilo suppressalis (Walker) larvae].  

PubMed

Aimed to understand the mechanisms of cold-resistance of overwintering Chilo suppressalis (Walker) larvae at physiological and biochemical levels, the supercooling point (SCP) and the contents of water, ash, elements, fat, fatty acid, glycrol, total sugar, and protein in the larvae samples collected at different time were determined. The results showed that the SCP and the contents of free water, dissociated fat, total sugar, and protein in the overwintering larvae decreased first and increased then, whereas the contents of bound water, ash, combined fat, K, Na, Mg, Fe, Ni and Cr, and glycerol decreased after an initial increase. The components of fatty acids in overwintering larvae had some changes, but the main components were still 9-hexadecenoic acid, 9-hexadecanoic acid, and 9-octadecenoic acid. The contents of 9-hexadecenoic acid and 9-hexadecanoic acid decreased first and increased then, while that of 9-octadecenoic acid was in adverse. The dynamic changes of the contents of test substances could reflect the cold-resistance of overwintering C. suppressalis larvae. PMID:18533532

Qiang, Cheng-Kui; Du, Yu-Zhou; Yu, Ling-Ya; Cui, Ya-Dong; Lu, Ming-Xing; Zheng, Fu-Shan

2008-03-01

300

[Effects of temperature stress on physiological indices of Chilo suppressalis Walker (Lepidoptera: Pyralidae) diapause larvae].  

PubMed

To understand the physiological mechanisms of temperature stress on the diapause larvae of rice stem borer Chilo suppressalis Walker at physiological and biochemical levels, determinations were made on the contents of water, lipid, total sugar and low molecular mass carbohydrates and the activities of SOD, POD, CAT in the larvae after series temperature stress (STS) and gradient temperature stress (GTS). With the decrease of temperature, the water content in the larvae decreased, and the decrement below 0 degrees C was significantly larger in treatment GTS than in treatment STS. The lipid content in the larvae decreased gradually, but no significant difference was observed between treatments STS and GTS. The total sugar content in the larvae in treatment STS increased after an initial decrease, but that in treatment GTS continued to decline. Four species of low molecular carbohydrates, i. e. , trehalose, glucose, glycerol and fructose were detected in the larvae. In treatment STS, the contents of glycose, glycerol and fructose in the larvae decreased after an initial increase, while the trehalose content was in adverse. In treatment GTS, the trehalose content decreased first and increased then, the glucose and glycerol were in adverse, but the fructose content had little change. In the range from 14 to -14 degrees C, the SOD and POD activities in the larvae in treatment STS were significantly lower than those in treatment GTS, but the CAT activity was in adverse. The changes of these indices reflected the physiological responses of C. suppressalis diapause larvae to different temperature stress. PMID:22919850

Qiang, Cheng-Kui; Du, Yu-Zhou; Yu, Ling-Ya; Qin, Yue-Hua; Feng, Wu-Jian

2012-05-01

301

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

302

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

PubMed

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

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

2012-02-01

303

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

PubMed

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

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

2012-01-01

304

Effects of Agaricus brasiliensis mushroom in Walker-256 tumor-bearing rats.  

PubMed

Agaricus brasiliensis is a mushroom native to São Paulo State, Brazil, that is studied for its medicinal proprieties. This work aimed to investigate the antitumoral activity of A. brasiliensis extracts and pure powdered basidiocarp preparation using Walker-256 (W256) tumor-bearing rats, a model for cancer-related cachexia studies. The rats were treated for 14 days by gavage (136 mg/kg) and at the end of the experiment tumors were collected to calculate mass and volume. Blood was collected for determination of plasma glucose, albumin, alanine aminotransferase (ALT), and aspartate aminotransferase (AST). Hepatic and tumor enzymes indicating oxidative stress were also evaluated. The results showed that all 4 treatments (pure powdered basidiocarp and aqueous, acid, and alkaline extracts) significantly reduced tumor size and promoted gain in body weight. Plasmatic analysis showed a reduction in AST level and increased glycemia in the treated rats. Pure basidiocarp preparations improved the liver catalase and superoxide dismutase activity, but did not change the glutathione S-transferase activity. The data collected from the W256 tumor-bearing rats revealed the beneficial effects of A. brasiliensis in tumor treatment, mainly related to cachexia. The benefits can be partly related to antioxidant activity and to reduction of weight loss and tumor growth. PMID:20130735

Jumes, Fernanda Menon Dias; Lugarini, Daiana; Pereira, Amanda Leite Bastos; de Oliveira, Anabel; Christoff, Adriana de Oliveira; Linde, Giani Andrea; do Valle, Juliana Silveira; Colauto, Nelson Barros; Acco, Alexandra

2010-01-01

305

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

PubMed Central

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

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

2012-01-01

306

[Concordance between vasopressin gene expression and growth of Walker 256 carcinosarcoma in rats].  

PubMed

The growth features of Walker 256 carcinosarcoma in rats of different genotypes were investigated. The experiments has been carried out on rats of the inbred Brattleboro and WAG lines, as well as on their hybrids segregated during congenic translocation of the normal vasopressin gene to the genotype of the Brattleboro rats. Brattleboro rats do not express the vasopressin gene. It has been found that there are only two types of tumor growth dynamics. In rats of the inbred Brattleboro line and in homozygotes di/di, that were segregated by backcrossings of heterozygous offsprings from the original crossbreeding between (WAG x Brattleboro) F1 x Brattleboro and the individuals with parental Brattleboro genotype, having grown to some extent the tumor regresses and disappears. In hybrid heterozygous siblings of di/+ genotype tumor grows linearly with time and always leads to fatal outcome. It has been found that, in the congenic procedure, the tumor regression trait is stably maintained and persistently inherited in lineage concordantly with the di/di genotype and, in rats with at least one allele of a normally expressed vasopressin gene, continuous and lethal tumor growth is always observed. PMID:23866631

Khega?, I I

2013-04-01

307

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

USGS Publications Warehouse

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

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

2004-01-01

308

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

NASA Astrophysics Data System (ADS)

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

Bayr, Tobias; Dommenget, Dietmar

2013-04-01

309

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

PubMed Central

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 sp., 16 to Babesia canis, and 25 to Bartonella vinsonii, and 22 seroconverted to Rickettsia rickettsii antigens. According to PCR results, 15 dogs were infected with Ehrlichia canis, 9 with Ehrlichia chaffeensis, 8 with Ehrlichia ewingii, 3 with Ehrlichia equi, 9 with Ehrlichia platys, 20 with a Rickettsia species, 16 with a Bartonella species, and 7 with B. canis. The detection of DNA from any Ehrlichia species was associated with clinical illness and with concurrent B. canis infection (by PCR). Both E. canis and an uncharacterized Rickettsia species appeared to result in chronic or recurrent infection. Death in the dog population was associated with living in a dirt lot rather than the concrete kennel. Of 23 people on whom serologic testing was conducted, eight were seroreactive to Bartonella henselae, one to E. chaffeensis, and one to R. rickettsii antigen; however, none had clinical or hematologic abnormalities consistent with illness caused by these organisms. We conclude that kennel dogs with heavy tick exposure can be infected at a high rate with multiple, potentially zoonotic, tick-borne pathogens. In addition, our findings further illustrate the utility of PCR for documenting coinfection with tick-transmitted pathogens.

Kordick, S. K.; Breitschwerdt, E. B.; Hegarty, B. C.; Southwick, K. L.; Colitz, C. M.; Hancock, S. I.; Bradley, J. M.; Rumbough, R.; Mcpherson, J. T.; MacCormack, J. N.

1999-01-01

310

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

NASA Astrophysics Data System (ADS)

In west-central Nevada, a transfer zone, which initiated in the mid-Miocene, presently links, via the Mina Deflection, right-lateral faults of the Eastern California Shear Zone to the south and the Central Nevada Seismic Belt and Walker Lane to the north. This transfer zone, the early inception of which is characterized by moderate (20-30°) clockwise crustal rotations previously identified (e.g., Candelaria Hills and surrounding ranges), along with right-lateral structures to the south and north, are part of a diffuse zone of intracontinental deformation that accommodates some 25 percent of the motion between the Pacific and North American plates. Although the northern and western boundaries of the transfer zone are relatively well defined by paleomagnetic data, the eastern and southeastern boundaries remain poorly constrained. Additional paleomagnetic data are being obtained from mid-to-late Tertiary volcanic rocks, presumably lying within (e.g., Montezuma Range, Palmetto Mountains, Monte Cristo Range) and outside (e.g., Goldfield Hills, San Antonio Mountains, Slate Ridge) of the transfer zone. Areas outside of the transfer zone are inferred to have not undergone any appreciable rotation since its inception. Volcanic rocks as well as shallow intrusions ranging in age from Oligocene to mid-Pliocene have been sampled (N=187) from inside and outside of the inferred southern and eastern boundaries of the transfer zone. Overall, the collection responds very favorably to progressive demagnetization; initial results are tentatively interpreted as suggesting the absence of appreciable rotation of the San Antonio Range (Tonopah, Nevada area and farther north). The extent to which areas near the eastern and southeastern boundaries have been rotated is under investigation. These data will aid in a better understanding of differential block rotation and tilting throughout the development of the west-central Nevada transfer system from the mid-Miocene to late Pliocene.

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

2007-12-01

311

Changes in aboveground biomass and nutrient content on Walker Branch Watershed from 1967 to 1983  

SciTech Connect

The increment of forest biomass and nutrient content on Walker Branch Watershed, Tennessee, from 1967 to 1983 was interrupted by two insect outbreaks. An outbreak of the southern pine beetle in the early 1970s and an outbreak of the hickory borer in the late 1970s to early 1980s killed a number of shortleaf pine (Pinus echinata) and hickory (Carya spp.), respectively. Yellow-poplar (Liriodendron tulipifera) growth increased over this 16-year period, especially in response to the mortality of shortleaf pine. The net result of these events was little change in total biomass but a substantial shift in species composition (from pine to yellow-poplar) in the Pine forest type over this period. No species has yet responded to the mortality of hickory. Due to the shift in species composition in the Pine type, calcium and magnesium accumulation rates in biomass increased but foliage biomass decreased over the inventory period. There was little change in foliage biomass or nutrient content in other forest types, despite hickory mortality, since mortality occurred primarily among large trees having low foliage-to-woody-biomass ratios. The insect attacks, combined with apparently natural self-thinning, caused a large increase in standing dead biomass and in nutrient return via tree fall. This increased rate of return will substantially alter forest floor nutrient content and availability, especially with regard to calcium (where the calcium content of standing dead currently equals forest floor calcium content) and nitrogen (where inputs of woody litter will substantially alter carbon to nitrogen ratios). 23 refs., 7 figs., 2 tabs.

Johnson, D.W.; Henderson, G.S.; Harris, W.F.

1987-01-01

312

Experimental in vivo measurements of light emission in plants: a perspective dedicated to David Walker.  

PubMed

This review is dedicated to David Walker (1928-2012), a pioneer in the field of photosynthesis and chlorophyll fluorescence. We begin this review by presenting the history of light emission studies, from the ancient times. Light emission from plants is of several kinds: prompt fluorescence (PF), delayed fluorescence (DF), thermoluminescence, and phosphorescence. In this article, we focus on PF and DF. Chlorophyll a fluorescence measurements have been used for more than 80 years to study photosynthesis, particularly photosystem II (PSII) since 1961. This technique has become a regular trusted probe in agricultural and biological research. Many measured and calculated parameters are good biomarkers or indicators of plant tolerance to different abiotic and biotic stressors. This would never have been possible without the rapid development of new fluorometers. To date, most of these instruments are based mainly on two different operational principles for measuring variable chlorophyll a fluorescence: (1) a PF signal produced following a pulse-amplitude-modulated excitation and (2) a PF signal emitted during a strong continuous actinic excitation. In addition to fluorometers, other instruments have been developed to measure additional signals, such as DF, originating from PSII, and light-induced absorbance changes due to the photooxidation of P700, from PSI, measured as the absorption decrease (photobleaching) at about 705 nm, or increase at 820 nm. In this review, the technical and theoretical basis of newly developed instruments, allowing for simultaneous measurement of the PF and the DF as well as other parameters is discussed. Special emphasis has been given to a description of comparative measurements on PF and DF. However, DF has been discussed in greater details, since it is much less used and less known than PF, but has a great potential to provide useful qualitative new information on the back reactions of PSII electron transfer. A review concerning the history of fluorometers is also presented. PMID:23065335

Kalaji, Hazem M; Goltsev, Vasilij; Bosa, Karolina; Allakhverdiev, Suleyman I; Strasser, Reto J; Govindjee

2012-10-13

313

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.

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

2013-01-01

314

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

NASA Astrophysics Data System (ADS)

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

Bellucci, S.; Saharian, A. A.

2013-09-01

315

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

PubMed

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. PMID:1227866

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

1975-12-01

316

Role of Signature Lysines in the Deviant Walker A Motifs of the ArsA ATPase†  

PubMed Central

The ArsA ATPase belongs to the P-loop GTPase subgroup within the GTPase superfamily of proteins. Members of this subgroup have a deviant Walker A motif which contains a signature lysine that is predicted to make intermonomer contact with the bound nucleotides and to play a role in ATP hydrolysis. ArsA has two signature lysines located at positions 16 and 335. The role of Lys16 in the A1 half and Lys335 in the A2 half was investigated by altering the lysines individually to alanine, arginine, leucine, methionine, glutamate, and glutamine by site-directed mutagenesis. While Lys16 mutants show similar resistance phenotypes as the wild type, the Lys335 mutants are sensitive to higher concentrations of arsenite. K16Q ArsA shows 70% of wild-type ATPase activity while K335Q ArsA is inactive. ArsA is activated by binding of Sb(III), and both wild-type and mutant ArsAs bind Sb(III) with a 1:1 stoichiometry. Although each ArsA binds nucleotide, the binding affinity decreases in the order wild type > K16Q > K335Q. The results of limited trypsin digestion analysis indicate that both wild type and K16Q adopt a similar conformation during activated catalysis, whereas K335Q adopts a conformation that is resistant to trypsin cleavage. These biochemical data along with structural modeling suggest that, although Lys16 is not critical for ATPase activity, Lys335 is involved in intersubunit interaction and activation of ATPase activity in both halves of the protein. Taken together, the results indicate that Lys16 and Lys335, located in the A1 and A2 halves of the protein, have different roles in ArsA catalysis, consistent with our proposal that the nucleotide binding domains in these two halves are functionally nonequivalent.

Fu, Hsueh-Liang; Ajees, A. Abdul; Rosen, Barry P.; Bhattacharjee, Hiranmoy

2013-01-01

317

Friedmann-Robertson-Walker brane cosmological equations from the five-dimensional bulk (A)dS black hole  

Microsoft Academic Search

In the first part of this work we review the equations of motion for the\\u000abrane presented in Friedmann-Robertson-Walker (FRW) form, when bulk is\\u000afive-dimensional (A)dS Black Hole. The spacelike (timelike) FRW brane equations\\u000aare considered from the point of view of their representation in the form\\u000asimilar to two-dimensional CFT entropy, so-called Cardy-Verlinde (CV) formula.\\u000aThe following five-dimensional gravities

Sergei D. ODINTSOV; Sachiko OGUSHI; Hashirimizu Yokosuka

2002-01-01

318

Fast domain wall dynamics in magnetic nanotubes: Suppression of Walker breakdown and Cherenkov-like spin wave emission  

NASA Astrophysics Data System (ADS)

We report on a micromagnetic study on domain wall (DW) propagation in ferromagnetic nanotubes. It is found that DWs in a tubular geometry are much more robust than ones in flat strips. This is explained by topological considerations. Our simulations show that the Walker breakdown of the DW can be completely suppressed. Constant DW velocities above 1000 m/s are achieved by small fields. A different velocity barrier of the DW propagation is encountered, which significantly reduces the DW mobility. This effect occurs as the DW reaches the phase velocity of spin waves (SWs), thereby triggering a Cherenkov-like emission of SWs.

Yan, Ming; Andreas, Christian; Kákay, Attila; García-Sánchez, Felipe; Hertel, Riccardo

2011-09-01

319

Scintigraphic visualisation of Walker carcinoma-256 in Sprague-Dawley rats by means of 99mTc-labelled monocytes.  

PubMed

Labelled macrophages accumulate in Walker carcinosarcoma-256 after 'in vivo' and 'in vitro' stimulation with a lectin and are therefore theoretically suitable for scintigraphic tumour detection. At present, routine application of the technique in man is precluded by: the use of PHA, and a labelling method for macrophages with considerable limitations to its application and which results in significant uptake of activity in liver and spleen. However, the purpose of the study was primarily to demonstrate the principle of a possible alternative to the use of labelled monoclonal antibodies for the scintigraphic detection of tumours. PMID:4039667

Schroth, H J; Oberhausen, E

1985-01-01

320

[Occurrence of accidents caused by Lonomia obliqua Walker, in the State of Paraná between 1989 and 2001].  

PubMed

The present article aimed to show the distribution of accidents involving the caterpillar Lonomia obliqua, Walker, 1855, in the State of Paraná between 1989 and 2001. The data were obtained from the Environmental Health Department of Paraná. The information collected was mapped using the Arcview program, and maps of the seasonal occurrence of accidents were generated. This seasonality was correlated with the insects life cycle and summer was shown to be the period with greatest incidence of accidents. The greatest concentrations occurred in the central-southern, southeastern and southwestern regions of the State. PMID:17568899

Garcia, Claudia Moreira; Danni-Oliveira, Inês Moresco

321

Sex pheromone components of the fruit-tree leaf roller, Archips argyrospilus (Walker) (Lepidoptera: Tortricidae), in British Columbia  

Microsoft Academic Search

In field experiments in the Okanagan Valley, British Columbia, the pheromone blend of (11Z)-tetradecen-1-ol acetate (Z11-14:OAc), (11E)-tetradecen-1-ol acetate (E 11-14:OAc), (9Z)-tetradecen-1-ol acetate (Z9-14:OAc) and dodecan-1-ol acetate (12: OAc) at a 100:64:2:1 ratio (western FTLR blend) attracted significantly more male fruit-tree leaf roller (FTLR),Archips argyrospilus (Walker), than did the previously reported four-component blend and modifications thereof. Addition of (11Z)-tetradecen-1-ol (Z11-14:OH) to

J.-P. Deland; R. Gries; G. Gries; G. J. R. Judd; B. D. Roitberg

1993-01-01

322

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

NASA Astrophysics Data System (ADS)

The Late-Miocene Stanislaus Group of lavas and ignimbrites were deposited across a region of diverse tectonic rates and style. Distributed east of Sonora Pass across the Walker Lane Belt into Nevada, and extending as far west as Knights Ferry along the Stanislaus River in the central Sierran foothills, the Stanislaus Group’s distinctive lithologic and paleomagnetic characteristics provide the means to reconstruct tectonic evolution in this region. Motion of the Sierra Nevada microplate is relatively straightforward while the adjacent range front fault and Walker Lane are characterized by westward propagation with time, extensive complex faulting, and vertical axis rotation of fault bounded blocks. The Stanislaus Group is composed of: 1) Table Mountain Formation, dominantly latite lavas emplaced at about ~10 Ma, 2A) Tollhouse Flat Member of the dominantly quartz latite Eureka Valley Tuff (EVT), emplaced sometime during 9.4-9.8 Ma, 2B) Latite Flow Member of EVT, 2C) By-Day Member of EVT, 9.42±0.04 Ma, 2D) Upper Member of EVT 9.43±0.02 Ma, and 3) Dardanelle Formation, composed of latite lavas, which caps the Stanislaus Group. Because of wide areal distribution across the central Walker Lane, we have used members of the Stanislaus Group to evaluate and understand regional strain in this part of the North American-Pacific plate boundary, which currently accommodates ~25% of relative dextral plate motion. Paleomagnetic analysis has yielded multiple reference remanence directions for elements of the Stanislaus Group on the “relatively stable” Sierra Nevada microplate for comparison with those same units deposited within the extensively-faulted Walker Lane to the east. Preliminary results show tectonic domains near Bridgeport, CA in the 5-10 km size range displaying eastward-increasing vertical-axis block rotation. This west-to-east increase in rotation appears to sub-parallel the Sierran frontal fault system when analyzed with data from previous studies to the south. Several locations show domains of clockwise vertical-axis rotation up to 50° adjacent to regions of low or no rotation; indicating that simplistic block models of vertical-axis rotation accommodating dextral shear may require re-evaluation. Earthquake focal mechanism inversions have shown that strain near Bridgeport, CA is characterized by nearly pure normal faulting. As dip-slip faulting is not favorable to vertical-axis rotation, this suggests a change in style of strain accommodation since the time of Stanislaus Group emplacement. Ongoing work will refine tectonic domain boundaries within the research area to produce a kinematic model that includes changes in strain accommodation style and rates of vertical-axis rotation.

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

2010-12-01

323

On the motion and geometry of the Sierra Nevada Great Valley micro-plate: Implications for Walker Lane tectonics  

NASA Astrophysics Data System (ADS)

The Sierra Nevada Great Valley (SNGV) micro-plate, a.k.a. the Fresno block, has long been recognized as a tectonically stable entity within the Pacific North America plate boundary zone. Some early geodetic studies have confirmed and defined its rigid behavior. However, those studies were based on a very limited amount of geodetic station velocities, and were unable to assess the extent of rigidity towards the edges of the block. The San Andreas and Garlock fault systems define the western and southern edges of the block, but no such features are readily recognizable to the north and east, along the Walker Lane belt. A better assessment of the location of the boundary or transition between the stable SNGV block and the Walker Lane is important for three reasons. It will provide a better understanding of what controls Walker Lane development and evolution, it will provide important boundary conditions in understanding the present-day kinematics of the Walker Lane, and it is contributes to the assessment of seismic hazard levels for the Reno-Carson City area. We analyze data from all the available GPS sites in the greater SNGV region, including data from the SCIGN, BARD and BARGEN networks, semi-continuous data from our own MAGNET network, and campaign-style data (e.g., USGS, SCEC). Also we have started to analyze regional PBO sites, however time-series for most of those sites are at present too short to infer reliable velocity estimates. We use the GIPSY OASIS II software which employs precise point positioning using dual-frequency carrier phase and pseudorange data, and the precise orbit, clock, and reference frame transformation products publicly available from JPL. The analysis includes carrier phase ambiguity resolution and regional filtering. Using these velocities we perform a kinematic analysis of the station velocity solution, solving for an angular velocity that best describes the motion of the SNGV. We analyze the residuals to investigate where the SNGV borders lie and how deviations from block behavior relate to fault systems at the block boundary.

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

2006-12-01

324

Late Quaternary faulting in Clayton Valley, Nevada: Implications for distributed deformation in the eastern California shear zone-Walker Lane  

NASA Astrophysics Data System (ADS)

The Walker Lane is a key component of the Pacific-North America plate boundary. This transtensional region of right lateral strike-slip and normal faulting accommodates ~25% of the total relative motion between the Pacific and North American plates. Recent studies indicate a discrepancy between short- and long-term rates of right-lateral shear in the Walker Lane with geodetic measurements of ~9.3 mm/yr being more than double the late Pleistocene geologic rate of <3.5 mm/yr. The Walker Lane, therefore, provides an excellent natural laboratory in which to address one of the major unresolved questions in active tectonics: are rates of strain accumulation and release along active plate boundaries constant through space and time or are significant temporal and spatial variations common? The Clayton Valley fault system of the Silver Peak-Lone Mountain extensional complex (SPLM) is a prime candidate to account for part of the “missing” strain in the Walker Lane due to its dominantly down-to-the-NW orientation, which ultimately accommodates right lateral shear in the region. The distribution of late Quaternary faults and alluvial fan deposits in Clayton Valley was determined through detailed geologic mapping (1:10,000 scale), which resulted in eight individual units that are consistent with the well-established western U.S. alluvial stratigraphy. Differential GPS was used to survey the prominent normal fault scarps displacing the fan deposits and cosmogenic nuclide (TCN) geochronology depth profile samples were collected from four units (Q2b, Q2c, Q2d, and Q3a). Displacement measured from the scarp profiles combined with TCN ages of the deformed fans will allow us to determine extension rates over multiple late Pleistocene time scales. Analysis of the Clayton Valley extension rates coupled with those from nearby structures, such as the Lone Mountain and Lida faults, will help determine if slip along these extensional faults can account for the observed discrepancy between short- and long-term rates of deformation along this important component of the Pacific-North America plate boundary.

Foy, T. A.; Lifton, Z. M.; Frankel, K. L.; Johnson, C.

2010-12-01

325

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

326

The hydroxyl group of S685 in Walker A motif and the carboxyl group of D792 in Walker B motif of NBD1 play a crucial role for multidrug resistance protein folding and function  

PubMed Central

Structural analysis of MRP1-NBD1 revealed that the Walker A S685 forms hydrogen-bond with the Walker B D792 and interacts with magnesium and the ?-phosphate of the bound ATP. We have found that substitution of the D792 with leucine resulted in misfolding of the protein. In this report we tested whether substitution of the S685 with residues that prevent formation of this hydrogen-bond would also cause misfolding. Indeed, substitution of the S685 with residues potentially preventing formation of this hydrogen-bond resulted in misfolding of the protein. In addition, some substitutions that might form hydrogen-bond with D792 also yielded immature protein. All these mutants are temperature-sensitive variants. However, these complex-glycosylated mature mutants prepared from the cells grown at 27 °C still significantly affect ATP binding and ATP-dependent solute transport. In contrast, substitution of the S685 with threonine yielded complex-glycosylated mature protein that is more active than the wild-type MRP1, indicating that the interaction between the hydroxyl group of 685 residue and the carboxyl group of D792 plays a crucial role for the protein folding and the interactions of the hydroxyl group at 685 with magnesium and the ?-phosphate of the bound ATP play an important role for ATP-binding and ATP-dependent solute transport.

Yang, Runying; Scavetta, Robert; Chang, Xiu-bao

2010-01-01

327

Endoscopic transaqueductal placement of a single-catheter cyst-ventriculoperitoneal shunt in a neonate with Dandy-Walker malformation-associated hydrocephalus: case report.  

PubMed

A neonate with hydrocephalus associated with Dandy-Walker malformation was successfully treated with an endoscopic placement of a transaqueductal ventricular single catheter. The modified catheter was provided with additional fenestration on its proximal side to allow simultaneous drainage from both the supra- and infratentorial compartments. This technique is well known for isolated fourth ventricles, but has not been applied to hydrocephalus associated with Dandy-Walker malformation. The cyst-ventriculoperitoneal shunt effectively drained both compartments. The patient was doing well 18 months after the surgical procedure. Endoscopic transaqueductal shunt placement can be considered, especially in patients with aqueductal patency. PMID:21441750

Morigaki, Ryoma; Pooh, Kyong-Hon; Nakagawa, Yoshinobu

2011-01-01

328

Identification of the products of mitochondrial transcription in the walker corcinosarcoma by the use of actinomycin D and ethidium bromide.  

PubMed

The major RNA species present in the purified mitochondrial fraction of the Walker carcinoma were investigated in order to determine which of them are located in the mitochondria and coded by the organelle DNA. The subcellular distribution of these RNA's and the in vivo sensitivity of the transcription process to selective inhibitors were examined. Among the different species separated by polyacrylamide gel electrophoresis, only the 21 and 16 Se RNA's were found exclusively in the purified mitochondria, approximately Se being the S value estimated from the relative electrophoretic mobility of the RNA. A bifid peak observed in the 16-15 Se region was shown to be an artifact caused by the ribonuclease inhibitor, naphthalene disulfonate. Ethidium bromide at high doses inhibited the incorporation in vivo of 32P into 21, 16, and 4 Se RNA, but the nuclear transcription of cytoplasmic RNA was also inhibited to the same extent. No significant effect was observed at lower doses. In contrast, actinomycin D exerted a differential inhibition of the synthesis of 28 and 18 Se RNA from both the cytoplasmic and the mitochondrial fractions, practically without affecting the transcription of the 21 and 16 Se species. The incorporation of 32P into mitochondrial 4 Se RNA was also considerably more resistant to the drug than the synthesis of the cytoplasmic tRNA. It is concluded that the 21, 16, and Se RNA's are the only major discrete species transcribed from mitochondrial DNA present in the Walker carcinoma. PMID:1268833

González-Cadavid, N F; Pérez, J L

1976-05-01

329

Comparative effect of a family of substituted thiopseudoureas on protein synthesis by rat liver and Walker carcinoma ribosomes.  

PubMed

In order to assess the role played respectively by the pseudothiourea group and the alkylic chain in the inhibition of protein synthesis and tumour growth caused by compound AHR-1911, a series of eight related substances were studied. The blockade of protein synthesis on liver and Walker carcinoma ribosomes and on suspensions of Walker carcinoma cells, depended essentially on the length of the alkylic chain and the substitution in C-1. The minimum chain was 9 carbons and a plateau in the activity was reached at 11 carbons. Replacement of the thiourea group in C-1 by an NH2 group did not change the pattern. A double bond in the distal section of the chain (AHR-1911) increased inhibition on intact cells with a parallel decrease in cytotoxicity, and reduced the aggregation of ribosomes, protein synthesis factors and other proteins. The antitumor effect depends on the pseudothiourea group and is not caused primarily by interference with protein synthesis. Aminoacyl tRNA binding and transfer appeared to be targets of AH4-1911, but this did not affect significantly tRNA change or nascent peptide release. Drug binding to ribosomes and their subsequent aggregation can be regulated by K+ concentration and temperature. It is assumed that the inhibition of protein synthesis is caused by AHR-1911 effects on elongation factors, impairing their interaction with ribosomes. PMID:699180

Carmona, A; Gonzalez-Cadavid, N F

1978-09-01

330

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

PubMed

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

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

2011-10-07

331

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

332

Walker carcinosarcoma cells damage endothelial cells by the generation of reactive oxygen species.  

PubMed Central

The passage of circulating tumor cells across vessel walls is an important step in cancer metastasis and is promoted by endothelial injury. Because Walker carcinosarcoma 256 (W256) cells generate oxygen-derived free radicals after cellular activation, the authors tested the hypothesis that these cancer cells can damage endothelial monolayers by producing such reactive oxygen species. To confirm that oxygen-derived radicals can damage endothelial cells, 3H-2-deoxyglucose-labeled human endothelial cell monolayers were exposed to xanthine oxidase in the presence of 0.2 mmol/l xanthine. 3H-2-deoxyglucose release was observed after the addition of xanthine oxidase in concentrations ranging from 6.5 x 10(-3) to 52 x 10(-3) units/ml. The extent of damage correlated with xanthine oxidase-dependent chemiluminescence (r = 0.91). Chemiluminescence assays in the presence of 5 x 10(-5) M luminol confirmed activation of the W256 cells by 1 x 10(-6) M chemotactic peptide fMLP. When fMLP-activated activated W256 cells were incubated with endothelial monolayers, concentrations of 2 x 10(6) to 6 x 10(6) W256 cells/ml were found to cause a 27% increase in the specific release of 2-deoxyglucose after a 90-minute incubation. A small but significant increase in 3H-2-deoxyglucose release also was observed in the absence of fMLP. Detection of 3H-2-deoxyglucose release in the presence of activated or unactivated tumor cells was dependent on preincubating the endothelial cell monolayer with 1 mM buthionine sulfoximine, an inhibitor of glutathione synthesis. Under these conditions, the specific release of 3H-2-deoxyglucose was increased from nondetectable levels to 21%, in the presence of 6.5 x 10(-3) units of the oxidase. Cultured W256 cells promoted isotope release from endothelial cell monolayers when activated with phorbol myristate acetate. Catalase (1000 units/ml) inhibited the tumor cell-induced release of 3H-2-deoxyglucose by 84% whereas superoxide dismutase, even at concentrations of 1 mg/ml, had no effect. A requirement for cell contact was shown because addition of cell-free supernatants from fMLP activated tumor cells did not cause 3H-2-deoxyglucose release and because pretreatment of W256 cells with 1 microM cytochalasin B inhibited their ability to promote isotope release even while increasing tumor cell-generated chemiluminescence threefold. Electron microscopy revealed that fewer cytochalasin B-treated W256 cells were attached to the endothelial cell monolayer than in untreated controls. It is concluded that the W256 tumor cells can damage endothelial cells directly via a mechanism involving production of reactive oxygen species. Images Figure 5

Shaughnessy, S. G.; Buchanan, M. R.; Turple, S.; Richardson, M.; Orr, F. W.

1989-01-01

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

Changes in red blood cell osmotic fragility induced by total plasma and plasma fractions obtained from rats bearing progressive and regressive variants of the Walker 256 tumor  

Microsoft Academic Search

Two variants (A and B) of the widely employed Walker 256 rat tumor cells are known. When inoculated sc, the A variant produces solid, invasive, highly metastasizing tumors that cause severe systemic effects and death. We have obtained a regressive variant (AR) whose sc growth is slower, resulting in 70-80% regression followed by development of immunity against A and AR

T. C. Cavalcanti; C. C. Gregorini; F. Guimarães; O. Rettori; A. N. Vieira-Matos

2003-01-01

335

Host range of Tetramesa romana Walker (Hymenoptera: Eurytomidae), a potential biological control of giant reed, Arundo donax L. in North America  

Technology Transfer Automated Retrieval System (TEKTRAN)

The eurytomid wasp, Tetramesa romana Walker, was evaluated as a potential biological control agent of the invasive reed grass, Arundo donax in North America. No-choice tests and timed behavioral studies were used to determine the fundamental host range of two genotypes of the wasp collected from Gr...

336

Inhibition by Hydrazine Sulfate and Various Hydrazides, of in vivo Growth of Walker 256 Intramuscular Carcinoma, B16 Melanoma, Murphy-Sturm Lymphosarcoma and L-1210 Solid Leukemia  

Microsoft Academic Search

In a continuing study of the effects of inhibition of gluconeogenesis at the phosphoenolpyruvate carboxykinase (PEP CK reaction on in vivo growth of tumors, it has been shown that hydrazine sulfate, a known inhibitor of PEP CK, not only inhibits the Walker 256 intramuscular carcioma, the Murphy-Sturm lymphosarcoma and the B-16 melanoma, but also has an effect on the solid

J. Gold

1973-01-01

337

Enzymatic properties of ?- and ?-glocusidases extracted from midgut and salivary glands of rice striped stem borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae)  

Microsoft Academic Search

The study of digestive enzymes, especially in important pests like Chilo suppressalis Walker (Lepidoptera: Pyralidae), which are a key constraint on rice production in a wide area of the globe and also in Iran, could be a successful procedure in the development of a safe and useful control strategy. Glycosidase are a type of digestive enzymes which have a critical

Arash Zibaee; Ali Reza Bandani; Samar Ramzi

2009-01-01

338

Relationships between body weight of overwintering larvae and supercooling capacity; diapause intensity and post-diapause reproductive potential in Chilo suppressalis Walker  

Microsoft Academic Search

The rice stem borer, Chilo suppressalis Walker, overwinters in China as a larva in facultative diapause. The instars and body weights of overwintering larvae vary widely. In this paper, the relationships between body weight and supercooling capacity, diapause intensity and post-diapause reproductive potential of overwintering larvae collected in late-stage rice field were examined. There was a significant positive correlation between

Shu Xu; Ming-Liang Wang; Nan Ding; Wei-Hua Ma; Yan-Ning Li; Chao-Liang Lei; Xiao-Ping Wang

2011-01-01

339

The impact of green spruce aphid, Elatobium abietinum (Walker), on the growth of young Sitka spruce in Hafren forest, Wales: delayed effects on needle size limit wood production  

Microsoft Academic Search

Defoliation of 3-year-old Sitka spruce (Picea sitchensis (Bong.) Carr.) by green spruce aphid (Elatobium abietinum (Walker)), in a field experiment in Hafren forest, Wales, resulted in significantly shorter shoots being produced in the upper canopy in 1994, the year of infestation, and in 1995. The dry weight (DW) of individual needles produced by defoliated trees was also reduced, by up

N. A Straw; N. J Fielding; G Green; J Price

2002-01-01

340

Complement-dependent Effect of Normal Rabbit Serum on Trypan Blue Staining, Morphology, and Viability of Cultured Walker 2 5 6 Tumor Cells  

Microsoft Academic Search

SUMMARY Normal rabbit serum was found to be cytotoxic for the Walker ~56 tumor cell main- tained in tissue culture. XB and HeLa cells were unaffected. Cells exposed to serum could not be serially propagated, displayed degenerative changes of the cytoplasm, and were permeable to trypan blue. The serum was rendered nontoxic by being heated at 56 ~ C. for

ROBERT L. TUTTLE; J. H. SMITH FOUSHEE

341

Stimulation of bone resorption results in a selective increase in the growth rate of spontaneously metastatic Walker 256 cancer cells in bone  

Microsoft Academic Search

To test the hypothesis that bone metastasis is related to the rate of bone remodeling, we have examined the effect of enhanced bone resorption on the growth of spontaneously metastatic Walker 256 (W256) cancer cells. Bone resorption was stimulated in male Fischer rats by injecting Rice H-500 Leydig tumor cells subcutaneously. The resorptive response of the skeleton was confirmed in

Paul J. Kostenuik; Gurmit Singh; Kaye L. Suyama; F. William Orr

1992-01-01

342

Development of Experimental Models for Meningea! Neoplasia Using Intrathecal Injection of 9L Gliosarcoma and Walker 256 Carcinosarcoma in the Rat1  

Microsoft Academic Search

Two models for meningeal neoplasia have been developed in rats using intrathecal injection of 9L gliosarcoma and Walker 256 carcinosarcoma cells. Tumor cells were injected in unanesthe- tized animals through an indwelling catheter inserted at the cisterna magna to the level of the lumbar enlargement of the spinal cord. Survival of rats was dependent on the number of tumor cells

Kimberly L. Kooistra; Moses Rodriguez; Garth Powis; Tony L. Yaksh; Gail J. Harty; Joan F. Hilton; Edward R. Laws

343

Analysis of the Systemic Security Weaknesses of the U.S. Navy Fleet Broadcasting System, 1967-1974, as Exploited by CWO John Walker.  

National Technical Information Service (NTIS)

CWO John Walker led one of the most devastating spy rings ever unmasked in the United States. Along with his brother, son, and friend, he compromised U.S. Navy cryptographic systems and classified information from 1967 to 1985. This research focuses on ju...

L. J. Heath

2005-01-01

344

Host range of Tetramesa romana Walker (Hymenoptera: Eurytomidae), a potential biological control of giant reed, Arundo donax L. in North America  

Microsoft Academic Search

The eurytomid wasp, Tetramesa romana Walker was evaluated as a potential biological control agent of the invasive reed grass, Arundo donax in North America. No-choice tests and timed behavioral studies were used to determine the fundamental host range of two genotypes of the wasp collected from Granada, Spain and Perpignan, France. Thirty-five species, including two genotypes of A. donax and

John A. Goolsby; Patrick Moran

2009-01-01

345

Block Modeling of Crustal Deformation in the Northern Walker Lane, Western Basin and Range, to Improve Estimates of Seismic Hazard  

NASA Astrophysics Data System (ADS)

In the United States, seismic hazard is evaluated officially by the U.S. Geological Survey and published as estimates in the National Seismic Hazard Maps (NSHM) that depict the peak ground shaking at a specific level of likelihood. In the western Great Basin, the 2002 NSHM is based on a combination of seismic, geologic and geodetic data. However, a discrepancy between the deformation rate that is inferred from the geodetic data (e.g. GPS) and geologic data (e.g. slip rates from fault studies) led to the introduction of an ad hoc zone of crustal shear strain in the western Basin and Range. Only then was the shaking risk portrayed in the NSHM consistent with the relative geodetic velocity of the Sierra Nevada microplate with respect to the central Great Basin. Since creation of the 2002 NSHM there has been a rapid increase in the quantity, quality and spatial coverage of GPS data in the western Great Basin, providing a vast improvement on the constraint on the pattern of crustal deformation. Thus geodesy is poised to make a substantial contribution to the spatial localization of seismic hazard in support of the next generation NSHM. In the Walker Lane ~10 mm/yr of relative motion are accommodated as shear and extension along a ~200 km wide and ~1000 km long zone of intracontinental deformation associated with the Pacific/North American plate boundary. We integrate GPS velocities obtained from sites in the continuous BARGEN, PBO, BARD, semi-continuous MAGNET network plus campaign results from numerous published results to constrain block models of crustal deformation. In so doing we estimate slip rates on block-bounding faults that have regional kinematic self-consistency and can be easily incorporated into the USGS algorithms that compute estimates for seismic hazard. Because of the large number and high density of candidate faults, and length of this zone we divide the region into three parts covering the Northern, Central and Southern Walker Lane. We have completed building the models for the northern Walker Lane (latitude 38.5 to 40.5 degrees, longitude - 120 to -117 degrees) and will present results from this section. The model has 62 blocks with mean dimension of ~30 km on a side, and thus the blocks are small compared to the width of the expected signal owing to elastic strain accumulation across locked faults. This starting number of blocks is purposefully large. We will discuss the ability that the data have to resolve details in the pattern of crustal deformation, and make a special effort to quantify the uncertainties and trade-offs in slip rates of nearby faults whose strain signals can overlap.

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

2007-05-01

346

Interstitial deletion of 8q21{yields}22 associated with minor anomalies, congenital heart defect, and Dandy-Walker variant  

SciTech Connect

We describe an infant with a deletion of 8q21{yields}22 who had distinct clinical manifestations including minor facial anomalies, a congenital heart defect, a Dandy-Walker variant, and mild to moderate developmental delay. Her facial characteristics included small, wide-spaced eyes, asymmetric bilateral epicanthal folds, a broad nasal bridge, a {open_quotes}carp-shaped{close_quotes} mouth, micrognathia, and prominent, apparently low-set ears. Three other reports describe children with larger proximal deletions of 8q that include 8q21 and q22. These four children all have similar facial appearance. Of the others reported, one had a congenital heart defect and one had craniosynostosis. This case, in addition to the previously noted three cases, helps in delineating a recognizable syndrome. 12 refs., 3 figs., 1 tab.

Donahue, M.L. [Medical Univ. of South Carolina, Charleston, SC (United States); Ryan, R.M. [Univ. of Rochester, NY (United States)

1995-03-13

347

Quantization of Friedmann-Robertson-Walker Spacetimes in the Presence of a Cosmological Constant and Stiff Matter  

NASA Astrophysics Data System (ADS)

In the present work, we study the quantum cosmology description of two Friedmann-Robertson-Walker models in the presence of a stiff matter perfect fluid and a negative cosmological constant. The models differ from each other by the constant curvature of the spatial sections, taken to be either positive or zero. We work in the Schutz's variational formalism, quantizing the models and obtaining the appropriate Wheeler-DeWitt equations. In these models there are bound states. Therefore, we compute, for each one, the discrete energy spectrum and the corresponding eigenfunctions. After that, we use the eigenfunctions in order to construct wave packets and evaluate the time-dependent expectation values of the scale factors. Each model shows bounded oscillations for the expectation value of the scalar factor, which is never zero, which can be interpreted as an initial indication that these models may not have singularities at the quantum level.

Oliveira-Neto, G.; Monerat, G. A.; Corrêa Silva, E. V.; Neves, C.; Ferreira Filho, L. G.

2013-09-01

348

[Biochemical investigations of cancer cachexia: I. Tumour induced changes of glycogenolysis and gluconeogenesis of Walker carcinoma bearing rats (author's transl)].  

PubMed

Rats (weight 150-200 g) bearing Walker-carcinoma showed tumour size dependent hypoglycemia, diminished mobilization of glycogen following glucagon stimulation and elevated values of the enzyme activity of glucose-6-(P)-ase. A further hormonal stimulation of this enzyme activity towards the values observed in normal rats after betamethasone stimulation was not possible. The values of the enzyme fructose-1,6-di-(P)-ase in liver of tumour bearing rats equalled those found in normal controls and did not show any rise after application of betamethasone. The serum levels of free fatty acids did not show any difference between normal controls and tumour bearing rats, and displayed an equal rise after intensive stimulation of peripheral lipolysis. PMID:175591

Schulze, B; Buchelt, L; Kurtze, G; Lorenz, H G

1976-01-01

349

[S35 lipoic acid distribution and its effect on pyruvate dehydrogenase activity in rats with Walker carcinoma].  

PubMed

S35-lipoic acid injected intraperitoneally in rats with Walker carcinosarcoma in a dose of 250 mg/Kg is accumulated in their organs and tissues to much higher concentrations compared with normal animals during all terms of the observation (15 min, 1 hour, 24 hours). Differences were especially great after 24 hours. Pyruvate dehydrogenase activity in tumor rats organs was considerably reduced when calculated per 1 Kg of tissue, but it is practically unchanged when calculated per 1 mg of protein, which amount in 1 g of tissue in them is distinctly lower than in normal animals. Single injections of lipoic acid in tumor-bearing rats do restore the enzyme activity to normal (in 1 hour), while repeated ones (10 days)--prolong animals lifeterms by 25%. PMID:339543

Karpov, L M; Dvuzhil'naia, E D; Savvov, V I; Phan Van Thuy

1977-01-01

350

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

USGS Publications Warehouse

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

Briggs, Richard W.; Hammond, William C.

2010-01-01

351

Present-Day Rates of Deformation Across the Southern Walker Lane From a Densified Regional GPS Network  

NASA Astrophysics Data System (ADS)

The Walker Lane is a diffuse region of right-lateral shear in western Nevada and eastern California that accommodates ~25% (9.3 ± 0.2 mm/yr) of the relative motion between the Pacific and North American plates. The region is characterized by discontinuous NNW-trending right-lateral strike-slip faults, and NE-trending, down-to-the-NW normal faults. The late Quaternary cumulative slip across the southern Walker Lane is only 1/3 the observed regional geodetic rate of right-lateral shear. We address this discrepancy between geologic and modern geodetic rates by installing and surveying a denser network of GPS monuments than previously existed. The higher spatial resolution will allow us to better define deformation rates in this complex tectonic setting. Our GPS data will be combined with accompanying fault kinematic and geochronologic data to determine deformation rates across multiple time scales, from late Quaternary to the present. We conducted a campaign GPS survey covering approximately 10,000 square kilometers encompassing the White Mountains, Fish Lake Valley, Clayton Valley, and the Silver Peak Range. We occupied 23 sites, including 10 newly installed monuments, which are spaced approximately 15-20 km apart. The existing sites used in this survey include the UNR-NEARNET sites, as well as a number of other campaign networks archived at UNAVCO. Stations with the longest history (including sites first surveyed as early as 1992) are expected to yield the most accurate results, while newer sites will help identify spatial patterns of strain partitioning. Monuments will be reoccupied annually and combined with past campaign survey data to determine modern crustal velocities. Initial results from this survey will be presented, which have important implications for understanding strain distribution along this important segment of the Pacific-North America boundary.

Lifton, Z. M.; Frankel, K. L.; Newman, A. V.; Foy, T. A.; Feng, L.; Johnson, C.; Dixon, T. H.

2010-12-01

352

Global design of satellite constellations: a multi-criteria performance comparison of classical walker patterns and new design patterns  

NASA Astrophysics Data System (ADS)

Basically, the problem of designing a multisatellite constellation exhibits a lot of parameters with many possible combinations: total number of satellites, orbital parameters of each individual satellite, number of orbital planes, number of satellites in each plane, spacings between satellites of each plane, spacings between orbital planes, relative phasings between consecutive orbital planes. Hopefully, some authors have theoretically solved this complex problem under simplified assumptions: the permanent (or continuous) coverage by a single and multiple satellites of the whole Earth and zonal areas has been entirely solved from a pure geometrical point of view. These solutions exhibit strong symmetry properties (e.g. Walker, Ballard, Rider, Draim constellations): altitude and inclination are identical, orbital planes and satellites are regularly spaced, etc. The problem with such constellations is their oversimplified and restricted geometrical assumption. In fact, the evaluation function which is used implicitly only takes into account the point-to-point visibility between users and satellites and does not deal with very important constraints and considerations that become mandatory when designing a real satellite system (e.g. robustness to satellite failures, total system cost, common view between satellites and ground stations, service availability and satellite reliability, launch and early operations phase, production constraints, etc.). An original and global methodology relying on a powerful optimization tool based on genetic algorithms has been developed at ALCATEL ESPACE. In this approach, symmetrical constellations can be used as initial conditions of the optimization process together with specific evaluation functions. A multi-criteria performance analysis is conducted and presented here in a parametric way in order to identify and evaluate the main sensitive parameters. Quantitative results are given for three examples in the fields of navigation, telecommunication and multimedia satellite systems. In particular, a new design pattern with very efficient properties in terms of robustness to satellite failures is presented and compared with classical Walker patterns.

Lansard, Erick; Frayssinhes, Eric; Palmade, Jean-Luc

353

Pamidronate corrects the down-regulation of the renal parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor mRNA in rats bearing Walker tumors.  

PubMed

Human hypercalcemia of malignancy (HHM) is generally due to the release into the circulation of parathyroid hormone-related peptide (PTHrP). PTHrP stimulates osteoclastic bone resorption and renal calcium reabsorption through the activation of a receptor similar to that of PTH (PTH-R). However, there is scarce information about the PTH-R regulation in the setting of the hypercalcemia. In the present study, we assessed the molecular basis of renal PTH-R regulation in Walker tumor-bearing rats either treated or not by a bisphosphonate, pamidronate. Twenty-seven 6-week-old rats were randomly divided into three experimental groups: WC- APD- (9 control rats), WC+ APD- (9 Walker tumor-bearing rats), and WC+ APD+ (9 Walker tumor-bearing rats receiving 15 mg/kg/day of sodium pamidronate every day for seven days). Pamidronate induced a significant decrease in the mean tumor weight (9.3+/-0.8 vs 6.3+/-0.6 g). Seven days after the subcutaneous implantation of the Walker cells, plasma total calcium was 10.8+/-0.4, 16.8+/-0.6, and 12.9+/-0.6 mg/dl in WC- APD-, WC+ APD-, and WC+ APD+, respectively. Plasma PTHrP concentration was undetectable, 15.9+/-2.6, and 7.2+/-1.4 pmol/l, respectively. Bone histomorphometric results showed high resorption in WC+ APD-, which returned below the basal level of the WC- APD- with pamidronate treatment. Densitometric analysis of Northern blots revealed that the renal PTH-R mRNA expression in WC+ WPD- rats was a quarter of the levels in the WC- APD- and WC+ APD+ groups. WC+ APD- also had a decreased PTH-stimulated cAMP production in renal membranes. The PTH-R was expressed in the Walker tumor and it was not modified by pamidronate treatment. In conclusion, the expression of PTH-R receptor mRNA is significantly reduced in the kidney of rats bearing Walker carcinoma tumor. Its regulation is tissue-specific: pamidronate, which partially corrected the hypercalcemia and elevated circulating PTHrP, normalized the PTH-R mRNA expression in the kidney but not in the tumor. PMID:9660083

Yaghoobian, J; Morieux, C; Denne, M A; Bouizar, Z; Ureña, P; de Vernejoul, M C

1998-05-01

354

Immunohistochemical study for the expression of Bcl-2 family proteins in Walker 256 carcinosarcoma cells under the influence of cytostatic drugs.  

PubMed

Immunohistochemical study was performed to evaluate the expression of Bcl-2 family proteins (Bcl-2, Bax, and Bad) in Walker 256 carcinosarcoma cells after implantation into the thigh muscle of male Wistar rats (10(6) cells). The experiment was conducted under conditions of spontaneous tumor development and individual or combined treatment with melatonin and cyclophosphamide. The use of melatonin as monotherapy or in combination with cyclophosphamide was followed by a significant decrease in Bcl-2 expression in carcinosarcoma cells. The Bcl-2/Bax and Bcl-2/Bad ratio was significantly reduced under these conditions (particularly after combined treatment with cytostatic drugs). These changes were accompanied by a significant (by 93.61%) decrease in the volume of transplantable tumor on day 14. Daily treatment with melatonin was accompanied by significant changes in the structure of Walker 256 carcinosarcoma. It was manifested in the formation of connective tissue septa and pseudofollicles. PMID:20396763

Ovsjanko, E V; Lushnikova, E L; Larionov, P M; Arkhipov, S A; Nepomnyashchikh, L M; Efremov, A V; Ovsjanko, Ya U

2009-10-01

355

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

PubMed

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

Pathak, Ekta; Atri, Neelam; Mishra, Rajeev

2013-01-09

356

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

PubMed Central

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

Pathak, Ekta; Atri, Neelam; Mishra, Rajeev

2013-01-01

357

Contribuicao ao estudo da radiosensibilidade do tumor de Walker 256 em ratos. Associacao da imunizacao previa com a acao da radiacao ionizante. (Contribution of radiosensitivity study for Walker 256 tumor in rats. Association of early immunization with action of ionizing radiation).  

National Technical Information Service (NTIS)

The suspension of tumoral cells from Walker 256 were irradiated with doses of 2.500, 4.500, 5.000, 5.500 and 7.500 rad for determining the attenuation dose. The suspension of inactives tumoral cells were injected in rats for verifying the immunized effect...

A. T. Y. Sakate

1979-01-01

358

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

Microsoft Academic Search

We previously reported a Vietnamese-American family with isolated autosomal dominant occipital cephalocele. Upon further neuroimaging\\u000a studies, we have recharacterized this condition as autosomal dominant Dandy-Walker with occipital cephalocele (ADDWOC). A\\u000a similar ADDWOC family from Brazil was also recently described. To determine the genetic etiology of ADDWOC, we performed genome-wide\\u000a linkage analysis on members of the Vietnamese-American and Brazilian pedigrees. Linkage

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

2008-01-01

359

Role of female-produced sex pheromone in behavioral reproductive isolation between Trichoplusia ni (Hübner) and Pseudoplusia includens (Walker) (Lepidoptera: Noctuidae, plusiinae)  

Microsoft Academic Search

In laboratory flight tunnel bioassays, response rates of male cabbage looper,Trichoplusia ni (Hübner), to female soybean looper,Pseudoplusia includens (Walker), were similar to response rates of maleT. ni to conspecific females for plume tracking and source contact. Male soybean loopers, however, exhibited a greatly reduced response to female cabbage loopers compared to conspecific females. Similar differences were observed in male responses

Peter J. Landolt; Robert R. Heath

1987-01-01

360

[Permeability of the mitochondrial membranes of the organs of white rats innoculated with Walker carcinoma to lipoic acid and thiamine labelled with S35].  

PubMed

Mitochondria isolated from organs of intact white rats and those with Walker carcinoma were incubated in Gubler medium containing S35-lipoic acid or S35-thiamine. An accumulation of lipoic acid by mitochondria is higher in tumor-bearing animals, while that of thiamine in most organs is lowered. In healthy animals mitochondria were found to accumulate S35-thiamine more intensively than S35-lipoic acid. In tumor animals these indices become nearly similar, while organ differences are leveled. PMID:1101537

Karpov, L M; Dvuzhil'naia, E D; Savvov, V I; Anisimov, V D

1975-01-01

361

A dynamic correspondence between Bose-Einstein condensates and Friedmann-Lemaitre-Robertson-Walker and Bianchi I cosmology with a cosmological constant  

SciTech Connect

In some interesting work of James Lidsey, the dynamics of Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmology with positive curvature and a perfect fluid matter source is shown to be modeled in terms of a time-dependent, harmonically trapped Bose-Einstein condensate. In the present work, we extend this dynamic correspondence to both FLRW and Bianchi I cosmologies in arbitrary dimension, especially when a cosmological constant is present.

D'Ambroise, Jennie; Williams, Floyd L. [Department of Mathematics, University of Massachusetts, Amherst, Massachusetts 01003 (United States)

2010-06-15

362

Relationships between structure and molting hormonal activity of tebufenozide, methoxyfenozide, and their analogs in cultured integument system of Chilo suppressalis Walker  

Microsoft Academic Search

The molting hormonal activity of methoxyfenozide (RH-2485), tebufenozide (RH-5992), five analogs with various alkyl groups, and 18 acyl analogs was measured by using cultured integument of rice stem borers, Chilo suppressalis Walker. The hormonal activity of methoxyfenozide was remarkably high (EC50 = 1.1 × 10?9 M), being equivalent to that of tebufenozide (RH-5992). The hormonal activity of several tebufenozide analogs

Yoshiaki Nakagawa; Kazunari Hattori; Chieka Minakuchi; Soichi Kugimiya; Tamio Ueno

2000-01-01

363

Effect of temperature on toxicity of pyrethroids and endosulfan, activity of mitochondrial Na +–K +ATPase and Ca 2+–Mg 2+ATPase in Chilo suppressalis (Walker) (Lepidoptera: Pyralidae)  

Microsoft Academic Search

The toxicity of deltamethrin, bifenthrin, and endosulfan to the fourth-instar larvae of rice stem borer, Chilo suppressalis (Walker), was measured at 17, 27, and 37°C. The three insecticides all displayed a positive temperature coefficient between 17 and 37°C. The temperature coefficients of deltamethrin, bifenthrin, and endosulfan were 5.59, 1.68, and 2.85, respectively. However, temperature coefficients of deltamethrin and bifenthrin between

Haiping Li; Tao Feng; Pei Liang; Xueyan Shi; Xiwu Gao; Hui Jiang

2006-01-01

364

Characterization and Localization of the Ice-Nucleating Active Agents in Larvae of the Rice Stem Borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae)  

Microsoft Academic Search

Chemical properties of the ice-nucleating active agents (INAs) distributed in the muscle of diapausing larvae of the rice stem borer, Chilo suppressalis Walker were studied. Sensitivity to protease indicated that the INAs were proteinaceous. The INAs were stable at at least 50°C for 5 min, and active over a broad pH range (pH 2.0 to 8.0) and after delipidation treatments.

Makoto Hirai; Hisaaki Tsumuki

1995-01-01

365

Pair creation by a photon and the time-reversed process in a Robertson-Walker universe with time-assymetric expansion  

Microsoft Academic Search

We investigate pair creation by a photon and the time-reversed process in a spatially flat Robertson-Walker universe. The expansion law C(eta) = Cin + exp(2beta) provides a time-asymmetric background gravitational field. The explicit evaluation of the total decay probabilities for electron-positron pairs which are non-relativistic at Compton time and soft photons yields a violation of CPT invariance such that the

K.-H. Lotze

1989-01-01

366

Mount Logan Ice Core Evidence for Changes in the Hadley and Walker Circulations Following the End of the \\\\Little Ice Age  

Microsoft Academic Search

The Hadley and Walker circulations dominate the climate of the tropics and contribute to extratropical climate variability\\u000a through the forcing of planetary waves that result in the long-range correlation of atmospheric circulation patterns known\\u000a as teleconnections. Previous work showed that an annually resolved 301-year ice core record of annual snow accumulation from\\u000a a highelevation site on Mount Logan in northwestern

G. W. K. Moore; Keith Alverson; Gerald Holdsworth

2004-01-01

367

Data on ground-water quality for the Walker Lake 1 degree x 2 degree quadrangle, western Nevada and eastern California  

USGS Publications Warehouse

Water quality data for groundwater has been compiled for the Walker Lake 1 degree x 2 degree quadrangle which covers a portion of western Nevada and eastern California. Chemical characteristics of the water are shown on a map (at a scale of 1:250,000) and on trilinear diagrams for the major ions. The data for the area are also presented in a table. (USGS)

Welch, Alan H.; Williams, Rhea P.

1987-01-01

368

Fault Slip Partitioning in the Eastern California Shear Zone-Walker Lane Belt: Pliocene to Late Pleistocene Contraction Across the Mina Deflection  

Microsoft Academic Search

Two different mechanisms have been proposed for fault slip transfer between the subparallel NW-striking dextral- slip faults that dominant the Eastern California Shear Zone (ECSZ)-Walker Lane Belt (WLB). In the northern WLB, domains of sinistral-slip along NE-striking faults and clockwise block rotation within a zone of distributed deformation accommodated NW-dextral shear. A somewhat modified version of this mechanism was also

J. Lee; D. Stockli; J. Gosse

2007-01-01

369

Characterisation of Walker 256 breast carcinoma cells from two tumour cell banks as assessed using two models of secondary brain tumours  

PubMed Central

Background Metastatic brain tumours are a common end stage of breast cancer progression, with significant associated morbidity and high mortality. Walker 256 is a rat breast carcinoma cell line syngeneic to Wistar rats and commonly used to induce secondary brain tumours. Previously there has been the assumption that the same cancer cell line from different cell banks behave in a similar manner, although recent studies have suggested that cell lines may change their characteristics over time in vitro. Methods In this study internal carotid artery injection and direct cerebral inoculation models of secondary brain tumours were used to determine the tumorigenicity of Walker 256 cells obtained from two cell banks, the American Type Culture Collection (ATCC), and the Cell Resource Centre for Medical Research at Tohoku University (CRCTU). Results Tumour incidence and volume, plus immunoreactivity to albumin, IBA1 and GFAP, were used as indicators of tumorigenicity and tumour interaction with the host brain microenvironment. CRCTU Walker 256 cells showed greater incidence, larger tumour volume, pronounced blood–brain barrier disruption and prominent glial response when compared to ATCC cell line. Conclusions These findings indicate that immortalised cancer cell lines obtained from different cell banks may have diverse characteristics and behaviour in vivo.

2013-01-01

370

Comparison of range of motion and function of subjects with reverse anatomy Bayley-Walker shoulder replacement with those of normal subjects.  

PubMed

Patients with rotator cuff tear and degenerative shoulder joint disease commonly experience severe pain and reduced performance during activities of daily living. A popular way to treat these patients is by means of reverse anatomy shoulder prosthesis. Studying the kinematics of subjects with reverse anatomy implant would be useful in order to gain knowledge about functionality of different designs. It is hypothesized that the kinematics of these subjects, in the absence of rotator cuff muscles, differs from that of normal subjects. In this study the upper limb kinematics of 12 subjects with a Bayley-Walker reverse anatomy shoulder prosthesis while performing tasks common in everyday activities and those that represent the range of motion was analyzed and compared to that of 12 normal subjects. Each patient also completed an Oxford Shoulder Score. Substantial reduction in the Bayley-Walker subjects' ranges of motion was observed compared to normal subjects. The mean abduction angle decreased from 109° (±20) for normal subjects to 64° (±25). A similar trend was observed during flexion and axial rotation tasks. Furthermore, the normal group showed less variable ranges of motion performing the standard tasks, whereas for the prosthetic group this varied greatly, which is likely to be dependent on muscle strength. Although the decreased range of motion was prominent, subjects were able to complete most of the tasks by compensating with their elbow and trunk. The most challenging task for Bayley-Walker subjects was lifting an object to head height. PMID:21798610

Masjedi, Milad; Lovell, Cara; Johnson, Garth R

2011-07-27

371

[Effect of 5-fluorouracil and irradiation of the cell kinetics of Walker carcinoma and the small intestine in rats].  

PubMed

A therapeutic schedule of synchronizing cytostatical-radiological treatment often used in human medicine is applied to rats carrying a Walker tumor. The effect of this treatment on the kinetics of tumor cells and epithelium of small intestine is investigated. 1. 5-Fluorouracil, i.p. during 18 and 12 hours, brings about no changes in the mitotic index; however, in the curve of marked mitoses a small fraction of cells is represented which is considered to be a consequence of the synchronization of a very small portion of tumor cells. 2. If ten hours after 5-FU-injection the cells are irradiated with a single dose of 300 rd, there occurs a distinct G2-block and a lengthening of the S-phase. These changes are found both in the 5-FU ground and in the controls. 3. 5-FU-injection thrice alternated with irradiation likewise causes a G2-block. After solution of the block a delayed increase of mitoses in the controls is going on which cannot be detected in the 5-FU group. These findings are interpreted as an effect of 5-FU on the proliferation rate of tumor tissues. PMID:1166476

Jentzsch, K

1975-07-01

372

Developmental changes in point-light walker processing during childhood: a two-year follow-up ERP study.  

PubMed

Event-related potentials were measured in twenty-four children aged 6-15 years, at one-year intervals for two years, to investigate developmental changes in each subject's neural response to a point-light walker (PLW) and a scrambled PLW (sPLW) stimulus. One positive peak (P1) and two negative peaks (N1 and N2) were observed in both occipitotemporal regions at approximately 130, 200, and 300-400ms. The amplitude and latency of the P1 component measured by the occipital electrode decreased during development over the first one-year period. Negative amplitudes of both N1 and N2, induced by the PLW stimulus, were significantly larger than those induced by the sPLW stimulus. Moreover, for the P1-N1 amplitude, the values for the eight-year-old children were significantly larger than those for the twelve-year-old children. N1 and N2 latency at certain electrodes decreased with age, but no consistent changes were observed. These results suggest that enhanced electrophysiological responses to PLW can be observed in all age groups, and that the early components were changed even over the course of a single year at the age of twelve. PMID:23376474

Hirai, Masahiro; Watanabe, Shoko; Honda, Yukiko; Kakigi, Ryusuke

2013-01-14

373

Chemical composition and antimicrobial and allelopathic activity of Tunisian Conyza sumatrensis (Retz.) E.WALKER essential oils.  

PubMed

Conyza sumatrensis (Retz.) E.WALKER (Asteraceae) is a spontaneous annual herb, fairly widespread throughout Tunisia, which has rarely been studied or valued in any sector. Essential oils were obtained by hydrodistillation of different parts (flower heads, leaves, stems, and roots) of C. sumatrensis plants, which were collected in autumn (November 2007) at the flowering stage in the area of Monastir, Tunisia. In total, 98 compounds, representing 88.1-99.3% of the oil composition, were identified by GC-FID and GC/MS analyses. The root essential oil was distinguished by its high content in acetylenes (matricaria ester, 4; 74.3%), while those from flower heads and leaves were dominated by oxygenated sesquiterpenes (61.1 and 50.3%, resp.). The oils of C. sumatrensis from Tunisia belonged to a matricaria ester/caryophyllene oxide chemotype. All the oils were evaluated for antibacterial, antifungal, and allelopathic activities. The results indicate that the leaf oil exhibited significant in vitro antibacterial activity against Enterococcus faecalis, Staphylococcus aureus, and Proteus mirabilis and that the C. sumatrensis oils isolated from the aerial parts presented high mycelia-growth inhibition of Candida albicans and the filamentous fungi tested. Moreover, the essential oils of the different plant parts inhibited the shoot and root growth of Raphanus sativus (radish) seedlings. Indeed, the inhibition of the hypocotyl growth varied from 28.6 to 90.1% and that of the radicle from 42.3 to 96.2%. PMID:23418168

Mabrouk, Samia; Salah, Karima Bel Hadj; Elaissi, Ameur; Jlaiel, Lobna; Jannet, Hichem Ben; Aouni, Mahjoub; Harzallah-Skhiri, Fethia

2013-02-01

374

Exploring the midgut transcriptome and brush border membrane vesicle proteome of the rice stem borer, Chilo suppressalis (Walker).  

PubMed

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

Ma, Weihua; Zhang, Zan; Peng, Chuanhua; Wang, Xiaoping; Li, Fei; Lin, Yongjun

2012-05-29

375

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

NASA Astrophysics Data System (ADS)

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

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

2003-12-01

376

Short migration of methane into a gas hydrate-bearing sand layer at Walker Ridge, Gulf of Mexico  

NASA Astrophysics Data System (ADS)

AbstractThe mechanisms governing distribution of natural gas hydrates in marine sediment systems are not well understood. We focus on a hole in the Gulf of Mexico, <span class="hlt">Walker</span> Ridge Block 313 Hole H, where a 2.5-m-thick gas hydrate-bearing sand occurs within a 152-m-thick fine-grained mud interval containing gas hydrate in fractures. The gas hydrate-bearing sand is surrounded by two distinct hydrate-free zones (10-m-thick above and 3-m-thick below). We hypothesize that microbial methane generated within the hydrate-free zones diffused into the sand and formed gas hydrate. We show that the amount of methane produced in the hydrate-free zones is likely enough to explain the gas hydrate content of the sand layer. Additionally, we show that there is enough time for dissolved methane to diffuse from the hydrate-free zones into the sand. We conclude that methane transport over significant distances via fluid flow is not required but that microbial methane could migrate short distances to form gas hydrate in the sand layer.</p> <div class="credits"> <p class="dwt_author">Cook, Ann E.; Malinverno, Alberto</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">377</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23624704"> <span id="translatedtitle">Does freezing and dynamic flexing of frozen branches impact the cavitation resistance of Malus domestica and the Populus clone <span class="hlt">Walker</span>?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Frost damage to the xylem conduits of trees is a phenomenon of eco-physiological importance. It is often documented in terms of the percentage loss of conductivity (PLC), an indicator of air filling of the conduits. However, trees that refill their conduits in spring could be impacted more by damage to the conduits that reduce cavitation resistance, making them more susceptible to future drought events. We investigated whether ice formation, dynamic flexing of frozen branches or freeze-thaw events could reduce the cavitation resistance (cause "frost fatigue") in first-year shoots of apple (Malus domestica) and clonal hybrid cottonwood (<span class="hlt">Walker</span>). Frost fatigue was measured in terms of P50 (the negative xylem pressure required to cause a 50 % loss of conductivity). All treatment groups showed significant frost fatigue, with the exception of the pre-flushed, constantly frozen poplar branches. The P50 following freeze treatments was approximately 50 % of the pre-freeze values. The effect tended to be greater in freeze-thawed branches. Dynamic bending of the branches had no effect on either PLC or P50. In three out of four cases, there was a significant correlation between P50 and PLC. Frost fatigue occurred in both apple and poplar, two unrelated species with different drought and frost tolerances, suggesting that it may be a widespread phenomenon that could impact the ecophysiology of temperate forests. PMID:23624704</p> <div class="credits"> <p class="dwt_author">Christensen-Dalsgaard, Karen K; Tyree, Melvin T</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-28</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">378</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3362559"> <span id="translatedtitle">Exploring the Midgut Transcriptome and Brush Border Membrane Vesicle Proteome of the Rice Stem Borer, Chilo suppressalis (<span class="hlt">Walker</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The rice stem borer, Chilo suppressalis (<span class="hlt">Walker</span>) (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.</p> <div class="credits"> <p class="dwt_author">Peng, Chuanhua; Wang, Xiaoping; Li, Fei; Lin, Yongjun</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">379</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/931994"> <span id="translatedtitle">In-stream biotic control on nutrient biogeochemistry in a forested sheadwater tream, West Fork of <span class="hlt">Walker</span> Branch</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">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 <span class="hlt">Walker</span> 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.</p> <div class="credits"> <p class="dwt_author">Roberts, Brian J [ORNL; Mulholland, Patrick J [ORNL</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">380</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/238630"> <span id="translatedtitle">Characterisation of cyclic adenosine 3':5'-monophosphate phospodiesterase from <span class="hlt">Walker</span> carcinoma sensitive and resistant to bifunctional alkylating agents.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Walker</span> carcinoma cell lines sensitive or resistant to bifunctional alkylating agents have been found to contain multiple forms of cyclic AMP phosphodiesterase (3':5'-cyclic AMP 5'-nucleotidohydrolase, EC 3.1.4.17). These activities have been resolved using Sepharose 6B gel filtration and their apparent molecular weights have been estimated. The enzyme appears to occur in four active forms of apparent mol. wts of greater than 1 000 000, 430 000, 350 000 and 225 000, when assayed at low substrate concentrations. Evidence has been obtained which suggests that all four forms of the enzyme are composed of subunits of mol. wt of approximately 15 000 and are interconvertible. While the ionic strength of the buffer affected the predominance of the different forms, the presence of cyclic AMP at 10(-6) M had no effect on aggregation or dissociation of the enzyme. An activity shift from high molecular weight forms of the enzyme to low molecular weight forms has been found in the resistant tumour at low substrate concentration. No change in elution profile between sensitive and resistant tumours was observed for the low affinity form of the enzyme. The pH optima of the enzymes with both high and low affinity for the substrate was found to be pH 8.0 in the sensitive line. In the resistant tumour the pH optima of the high affinity form is shifted to pH 8.4 while the low affinity form remains at pH 8.0. The high affinity forms of the phosphodiesterase in the sensitive and resistant tumour also differed in their inhibition by theophylline. In both cases inhibition was of the competitive type with Ki values for the sensitive and resistant lines being 2.35 and 0.32 mM, respectively. There was no significant difference in the inhibition of the low affinity form between the sensitive and resistant tumour. PMID:238630</p> <div class="credits"> <p class="dwt_author">Tisdale, M J</p> <p class="dwt_publisher"></p> <p class="publishDate">1975-07-27</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return 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<a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a style="font-weight: bold;">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_21");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">381</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=521095"> <span id="translatedtitle">Targeted disruption of the <span class="hlt">Walker</span>-Warburg syndrome gene Pomt1 in mouse results in embryonic lethality</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">O-mannosylation is an important protein modification in eukaryotes that is initiated by an evolutionarily conserved family of protein O-mannosyltransferases. The first mammalian protein O-mannosyltransferase gene described was the human POMT1. Mutations in the hPOMT1 gene are responsible for <span class="hlt">Walker</span>–Warburg syndrome (WWS), a severe recessive congenital muscular dystrophy associated with defects in neuronal migration that produce complex brain and eye abnormalities. During embryogenesis, the murine Pomt1 gene is prominently expressed in the neural tube, the developing eye, and the mesenchyme. These sites of expression correlate with those in which the main tissue alterations are observed in WWS patients. We have inactivated a Pomt1 allele by gene targeting in embryonic stem cells and produced chimeras transmitting the defect allele to offspring. Although heterozygous mice were viable and fertile, the total absence of Pomt1–/– pups in the progeny of heterozygous intercrosses indicated that this genotype is embryonic lethal. An analysis of the mutant phenotype revealed that homozygous Pomt1–/– mice suffer developmental arrest around embryonic day (E) 7.5 and die between E7.5 and E9.5. The Pomt1–/– embryos present defects in the formation of Reichert's membrane, the first basement membrane to form in the embryo. The failure of this membrane to form appears to be the result of abnormal glycosylation and maturation of dystroglycan that may impair recruitment of laminin, a structural component required for the formation of Reichert's membrane in rodents. The targeted disruption of mPomt1 represents an example of an engineered deletion of a known glycosyltransferase involved in O-mannosyl glycan synthesis.</p> <div class="credits"> <p class="dwt_author">Willer, Tobias; Prados, Belen; Falcon-Perez, Juan Manuel; Renner-Muller, Ingrid; Przemeck, Gerhard K. H.; Lommel, Mark; Coloma, Antonio; Valero, M. Carmen; de Angelis, Martin Hrabe; Tanner, Widmar; Wolf, Eckhard; Strahl, Sabine; Cruces, Jesus</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">382</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22251743"> <span id="translatedtitle">Seasonal expression of Bt proteins in transgenic rice lines and the resistance against Asiatic rice borer Chilo suppressalis (<span class="hlt">Walker</span>).</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Laboratory bioassays and field surveys were carried out to compare the resistance of three transgenic rice (Oryza sativa L.) lines including Bt-DL expressing a single gene cry1Ab, Bt-KF6 expressing stacked genes cry1Ac and CpTI genes and Bt-SY63 expressing a fusion gene cry1Ab/cry1Ac, respectively, to an important rice pest Chilo suppressalis (<span class="hlt">Walker</span>). In addition, enzyme-linked immunosorbent assays (ELISA) were conducted to monitor the Bt protein expressions in rice leaves and stems at different rice growth stages. Results showed that all the transgenic rice lines exhibited significantly high resistance to the pest compared with their corresponding nontransformed isolines. Among the transgenic rice lines, Bt-SY63 and Bt-KF6 had higher resistance to C. suppressalis at early growth stage, but lower resistance at late stages, while the pest resistance of Bt-DL was relatively stable throughout the growing season. The results were consistent with ELISA results showing that Bt protein levels in Bt-SY63 or Bt-KF6 leaves decreased in late growth stages, but were relatively stable in Bt-DL at all growth stages. This demonstrates that the resistance to a pest by Bt plants is positively correlated with Cry protein expression levels in plant tissues. Compared with Bt-SY63 and Bt-KF6, the Bt protein expression levels were significantly lower in Bt-DL, while its resistance to C. suppressalis was the highest. This may suggest that C. suppressalis is more susceptible to Cry1Ab than to Cry1Ac. The data from the current study are valuable for decision-making for commercial use of Bt rice lines and development of appropriate pest control and resistance management strategies for the transgenic rice lines. PMID:22251743</p> <div class="credits"> <p class="dwt_author">Zhang, Yongjun; Li, Yunhe; Zhang, Ying; Chen, Yang; Wu, Kongming; Peng, Yufa; Guo, Yuyuan</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">383</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/11262583"> <span id="translatedtitle">Effect of a leucine-supplemented diet on body composition changes in pregnant rats bearing <span class="hlt">Walker</span> 256 tumor.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Cancer patients present high mobilization of host protein, with a decrease in lean body mass and body fat depletion occurring in parallel to neoplastic growth. Since leucine is one of the principal amino acids used by skeletal muscle for energy, we investigated the changes in body composition of pregnant tumor-bearing rats after a leucine-supplemented diet. Sixty pregnant Wistar rats divided into six groups were fed a normal protein diet (18%, N) or a leucine-supplemented diet (3% L-leucine, L). The pregnant groups were: control (CN), <span class="hlt">Walker</span> 256 carcinoma-bearing rats (WN), control rats pair-fed with tumor-bearing rats (pfN), leucine-supplemented (CL), leucine-supplemented tumor-bearing (WL), and leucine-supplemented rats pair-fed with tumor-bearing rats (pfL). At the end of pregnancy, all animals were sacrificed and body weight and tumor and fetal weight were determined. The carcasses were then analyzed for water, fat and total, collagen and non-collagen nitrogen content. Carcass weight was reduced in the WN, WL, pfN and pfL groups compared to control. The lean body mass and total carcass nitrogen were reduced in both tumor-bearing groups. Despite tumor growth and a decrease in fetal weight, there was a slight decrease in collagen (7%) and non-collagen nitrogen (8%) in the WL group compared with the WN group which showed a decrease of 8 and 12%, respectively. Although the WL group presented severe tumor growth effects, total carcass nitrogen and non-collagen nitrogen were particularly higher in this leucine-supplemented group compared to the WN group. These data suggest that the leucine-supplemented diet had a beneficial effect, probably attenuating body wasting. PMID:11262583</p> <div class="credits"> <p class="dwt_author">Ventrucci, G; Mello, M A; Gomes-Marcondes, M C</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">384</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1997SPIE.2972...88N"> <span id="translatedtitle">Enhancement of photodynamic therapy due to hyperbaric hyperoxia: an experimental study of <span class="hlt">Walker</span> 256 tumors in rats</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Photodynamic therapy (PDT), which is now an approved treatment for many types of cancers, is based on the simultaneous involvement of three factors, namely: tumor tissue retention of a specific photosensitizer; local illumination of the lesion with a visible light source and the occurrence of oxygen in the triplet state. Theoretically, a change in any one of these factors may be compensated by a change in the other two factors, leading to the same therapeutic result. In practice, this is not true, since we are dealing with living tissue, but we may expect to find an ideal combination of these three factors which may give the best clinical results. In this work we present experimental results of PDT under Hyperbaric hyperoxia (HBO) in tumor masses of the dorsal subcutaneous tissue of rats. These tumors were created by previous inoculation of '<span class="hlt">Walker</span> 256' neoplastic cells Hematoporphyrin Ester (HpE) was administered as the photosensitizer. The rats were pressurized at up to 3 atm with a 100 percent continuous oxygen ventilation environment in a specially designed hyperbaric chamber. The skin area above the tumor was photosensitized for 45 minutes with a 7 mw HeNe laser. Twenty four hours later, the tumor was removed for study. In all the animals treated with PDT/HBO histology revealed a very important reduction in the number of tumor cells as compared with the PDT controls in normal atmospheric condition, showing numerous apoptotic as well as necrotic cells at the border of the radiated area. The observed enhancement in the PDT for this situation is, of course, related to the extra oxygen in the circulatory system.</p> <div class="credits"> <p class="dwt_author">Nicola, Jorge H.; Colussi, Valdir C.; Nicola, Ester M.; Metze, Konradin</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">385</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/3202902"> <span id="translatedtitle">A new cytotoxic, DNA interstrand crosslinking agent, 5-(aziridin-1-yl)-4-hydroxylamino-2-nitrobenzamide, is formed from 5-(aziridin-1-yl)-2,4-dinitrobenzamide (CB 1954) by a nitroreductase enzyme in <span class="hlt">Walker</span> carcinoma cells.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Walker</span> tumour cells in vivo or in vitro are exceptionally sensitive to the monofunctional alkylating agent 5-(aziridin-1-yl)-2,4-dinitrobenzamide (CB 1954) (Cobb LM et al., Biochem Pharmacol 18: 1519-1527, 1969). CB 1954 forms DNA interstrand crosslinks in a time-dependent manner in <span class="hlt">Walker</span> tumour cells but not in non-toxically affected Chinese hamster V79 cells [(Roberts JJ et al., Biochem Biophys Res Commun 140: 1073-1078, 1986)]. However, co-culturing Chinese hamster V79 cells with <span class="hlt">Walker</span> cells in the presence of CB 1954 renders the hamster cells sensitive to CB 1954 and leads to the formation of interstrand crosslinks in their DNA, findings indicative of the formation by <span class="hlt">Walker</span> cells of a diffusible toxic metabolite of CB 1954. A flavoprotein, of molecular weight 33.5 kDa as estimated by SDS-polyacrylamide gel electrophoresis, has been isolated from <span class="hlt">Walker</span> cells and identified as a form of NAD(P)H dehydrogenase (quinone) (DT diaphorase, EC 1.6.99.2). This enzyme, in the presence of NADH or NADPH, catalyses the aerobic reduction of CB 1954 to 5-(aziridin-1-yl)-4-hydroxylamino-2-nitrobenzamide. This new compound can form interstrand crosslinks in the DNA of Chinese hamster V79 cells to which it is also highly toxic. PMID:3202902</p> <div class="credits"> <p class="dwt_author">Knox, R J; Friedlos, F; Jarman, M; Roberts, J J</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-12-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">386</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/7235587"> <span id="translatedtitle">Wormhole spectrum of a quantum Friedmann-Robertson-<span class="hlt">Walker</span> cosmology minimally coupled to a power-law scalar field and the cosmological constant</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The expansion of the wave function of a quantum Friedmann-Robertson-<span class="hlt">Walker</span> cosmology minimally coupled to a scalar field with a power-law potential by its scalar-field part decouples the gravitational-field part into an infinite system of linear homogeneous differential equations (equivalent to a matrix equation). The solutions for the gravitational-field part are found in the product integral formulation. It is shown that there exists a spectrum of the wave functions exponentially damped for large three-geometries under the condition that the cosmological constant should vanish. These are interpeted as the Hawking-Page wormholes.</p> <div class="credits"> <p class="dwt_author">Kim, S.P. (Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States) Department of Physics Education, College of Education, Seoul National University, Seoul 151-742 (Korea, Republic of)); Page, D.N. (Theoretical Physics Institute, University of Alberta, Edmonton, Alberta, T6G 2J1 (Canada))</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-05-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">387</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001AGUFMGP11A0184P"> <span id="translatedtitle">Paleomagnetic Data from Upper Tertiary Volcanic Rocks in the Central <span class="hlt">Walker</span> Lane: Crustal-Scale Block Rotation and Transitional Field Directions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Late Cenozoic deformation is broadly distributed across the western plate boundary of North America from the San Andreas Fault system eastward into the Basin and Range Province. Comparison of plate motion and geodetic measurements indicates that 75 percent of the strain between the Pacific and North America plates is accommodated along the San Andreas with the residual strain partitioned inboard along the eastern California shear zone (ECSZ). Displacement is partitioned northward from the ECSZ to a narrow zone of deformation in the southern <span class="hlt">Walker</span> Lane along the Owens Valley and Furnace Creek fault systems. Recent GPS data from sites in the Central <span class="hlt">Walker</span> Lane indicate differential motion among tectonic blocks, which is interpreted to be a result of strain partitioning (Oldow et al., 2001). To in part quantify the magnitude of heterogeneous tectonic block rotation in the Neogene and to more clearly define block boundaries in the central <span class="hlt">Walker</span> Lane, reconnaissance paleomagnetic data have been obtained from upper Tertiary volcanic rocks in Candeleria Hills, Nevada. Eight to ten oriented samples from 47 sites have been demagnetized with all sites yielding interpretable results: 14 sites in mid Miocene andesite flows (Ta), 17 sites in upper Miocene basalt flows (Tb), and 16 sites in lower Miocene (?) rhyolite ash flow tuffs (Taf) (one site per eruptive flow unit). After removal of a recent viscous overprint (by 10-25 mT and 100° to 300° C) most samples yield one well-defined magnetization well-grouped at the site level. After correcting for the modest dip of the flows; Ta yield a normal polarity magnetization direction (D = 14.4° , I = 69.1° , ? 95 = 5.53° , ? = 101.2, 17N); Tb1 yield a dual polarity magnetization (D = 34.0° , I = 45.0° , ? 95 = 8.49° , ? = 43.5, N = 3R5N); Tb2 yield a reversed polarity magnetization (D = 204.1° , I = -56.0° , ? 95 = 7.53° , ? = 47.6, R9); Taf yield anomalous northeast-directed, moderate negative inclination magnetizations (12 sites) and northwest-directed, moderate to steep negative inclination magnetizations (4 sites). The data from sites in Ta and Tb are interpreted to reflect moderate clockwise vertical axis rotation of parts of the Candeleria Hills structural block and are consistent with tectonic block rotation accommodating crustal strain in the Central <span class="hlt">Walker</span> Lane since the Neogene. We tentatively interpret the anomalous directions from Taf to reflect either a high amplitude field excursion or the transitional part of a field reversal.</p> <div class="credits"> <p class="dwt_author">Petronis, M. S.; Geissman, J. W.; Oldow, J. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">388</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFM.G21A0662J"> <span id="translatedtitle">Constraints from GPS on Block Kinematics of the Transition between the Southern <span class="hlt">Walker</span> Lane and the Basin and Range Province</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The southern <span class="hlt">Walker</span> 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.</p> <div class="credits"> <p class="dwt_author">Jha, S.; Hammond, W. C.; Kreemer, C.; Blewitt, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">389</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/8557238"> <span id="translatedtitle">1,25 dihydroxyvitamin D and dexamethasone decrease in vivo <span class="hlt">Walker</span> carcinoma growth, but not parathyroid hormone related protein secretion.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Parathyroid hormone related protein (PTHrP) is produced by several breast cancers. 1,25 dihydroxyvitamin D (1,25[OH]2D) and Dexamethasone (DEX) have been shown to decrease PTHrP mRNA expression in several cell lines. We therefore tested the in vivo effect of both steroids on PTHrP secretion and tumor development of the <span class="hlt">Walker</span> carcinoma (WC). WC cells were injected subcutaneously in Fisher rats which were simultaneously treated with either vehicle, or 1,25(OH)2D (0.5 micrograms/kg/d) or DEX (2 mg/kg/d). After 7 days, tumor weight was significantly decreased in the 2 treated-groups as compared to the control group. Vehicle treated-rats developed hypercalcemia, which was also observed in rats treated with 1,25(OH)2D; by contrast, the plasma calcium was significantly decreased in the DEX-treated group compared to vehicle-treated rats. In a dose-effect experiment, this dose of 1,25(OH)2D induced marked hypercalcemia in rats not implanted with WC, but was required to decrease the tumor weight in implanted rats. In both 1,25(OH)2D and DEX-treated groups, plasma PTHrP levels were significantly decreased, but there was a similar correlation between PTHrP plasma level and tumor weight in the three groups. Indeed, the cytosolic PTHrP content/mg tumor was identical in the 3 groups. By contrast, the PTHrP/Actin mRNA in the tumor was significantly decreased in the 1,25(OH)2D group, comparatively to the vehicle and DEX groups. Our results show that Dexamethasone and 1,25(OH)2D decrease WC tumor development in vivo, but do not change the PTHrP secretion by the remaining tumor although steady state PTHrP mRNA content level is decreased by 1,25(OH)2D. PMID:8557238</p> <div class="credits"> <p class="dwt_author">Cohen-Solal, M E; Bouizar, Z; Denne, M A; Graulet, A M; Gueris, J; Bracq, S; Jullienne, A; de Vernejoul, M C</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">390</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AGUFMOS24A..04S"> <span id="translatedtitle">Gulf of Mexico Gas Hydrate Joint Industry Project Leg II: Results from the <span class="hlt">Walker</span> Ridge 313 Site</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Gulf of Mexico Gas Hydrate Joint Industry Project Leg II drilling program visited three sites in the Gulf of Mexico during a 21 day drilling program in April and May, 2009. Using both petroleum systems and seismic stratigraphic approaches, the exploration focus for Leg II was to identify sites with the potential for gas hydrate-saturated sand reservoirs. The data acquired consist of a comprehensive suite of high resolution LWD logs including gamma ray, density, porosity, sonic, and resistivity tools. No physical samples were taken in the field. Two holes, locations G and H, were drilled at the <span class="hlt">Walker</span> Ridge 313 site (WR 313)in the central Gulf of Mexico, just updip of the “salt sheet province”. The primary objective of each well was to determine the presence or absence of gas hydrate from the log data at the predetermined primary targets, picked from industry 3-D seismic data, in dipping Pleistocene turbidite derived sands on the flanks of a salt withdrawal minibasin. The seismic targets were high amplitude positive reflections just updip of phase reversals at the interpreted base of hydrate stability, corresponding to the so-called bottom simulating reflector, or “BSR”. Downdip of the BSR, the sands were clearly troughs, or negative reflections, suggesting free gas charge. An existing industry well, located updip of both JIP locations, contains a slightly sandy zone in the same stratigraphic interval as the JIP targets, that has elevated resistivities correlated to the target sands, suggesting low saturation “shows” of hydrate. Stratigraphically bounded fractured fine grained sediments with probable gas hydrate fill were found in both holes between 800 ft and 1300 ft at G, and between 600 ft and 1000 ft below the seafloor at H. At the primary targets, high saturation gas hydrates in sand were interpreted from logs at both holes. LWD data indicate 50 ft of high saturation gas hydrate in sands starting at 2722 ft below seafloor at the G hole. At H, 37 ft of high saturation gas hydrate was found in the target sand. Numerous minor occurrences of probable pore filling gas hydrate in thin sands were found at both locations. The likely discovery of thick gas hydrate-filled sands at the WR 313 site validates the exploration approach, and strongly indicates that gas hydrate can be found in reservoir quality marine sands. Additionally, the depth below mudline to which these wells were drilled without risers or drivepipe is unprecedented and the information gleaned will aid in marine hydrate exploration efforts worldwide.</p> <div class="credits"> <p class="dwt_author">Shedd, W.; Frye, M.; Boswell, R. M.; Collett, T. S.; McConnell, D.; Jones, E.; Shelander, D.; Dai, J.; Guerin, G.; Cook, A.; Mrozewski, S.; Godfriaux, P. D.; Dufrene, R.; Hutchinson, D. R.; Roy, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">391</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/1054990"> <span id="translatedtitle">Long-Term Data Reveal Patterns and Controls on Stream Water Chemistry in a Forested Stream: <span class="hlt">Walker</span> Branch, Tennessee</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We present 20 years of weekly stream water chemistry, hydrology, and climate data for the <span class="hlt">Walker</span> 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.</p> <div class="credits"> <p class="dwt_author">Lutz, Brian D [Duke University; Mulholland, Patrick J [ORNL; Bernhardt, Emily [Duke University</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">392</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1978012"> <span id="translatedtitle">Effects of staurosporine, K 252a and other structurally related protein kinase inhibitors on shape and locomotion of <span class="hlt">Walker</span> carcinosarcoma cells.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The structure/activity relationship of the protein kinase inhibitors, staurosporine and K 252a and their analogues on motility of <span class="hlt">Walker</span> carcinosarcoma cells has been studied in vitro. Staurosporine and K 252a, similar to phorbol myristate acetate (PMA) and diacylglycerols, suppress cell polarity and locomotor activity of <span class="hlt">Walker</span> carcinosarcoma cells. Staurosporine inhibits spontaneous and colchicine-induced front-tail polarity (ID50 of about 6.0 x 10(-8) M) as well as spontaneous and colchicine-stimulated locomotion at 10(-7) M. K 252a suppresses cell polarity (ID50 of about 4.5 x 10(-6) M) and inhibits spontaneous and colchicine-stimulated locomotion at 10(-5) M, but suppression of locomotor activity is not complete in the presence of colchicine. CGP 41251, a staurosporine derivative with a much higher specificity for protein kinase C (PKC) than staurosporine, induces a dose-dependent increase in the proportion of polarised cells, and stimulates cell locomotion. Two K252a analogues, KT 5720 and KT 5822, which act preferentially on cyclic nucleotide-dependent protein kinases, and CGP 42700, an inactive staurosporine analogue, had no effect on cell polarity and locomotion. The findings suggest that protein kinase inhibitors acting preferentially on PKC may be of interest in pharmacological regulation of tumour cell locomotion.</p> <div class="credits"> <p class="dwt_author">Zimmermann, A.; Keller, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">393</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23143316"> <span id="translatedtitle">From precocious fame to mature obscurity: David <span class="hlt">Walker</span> (1837-1917) MD, LRCSI, surgeon and naturalist to the Fox Arctic Expedition of 1857-59.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The Belfast-born David <span class="hlt">Walker</span> was the 19-year-old surgeon and naturalist on the epic Fox Arctic Expedition (1857-59) that established the fate of Sir John Franklin's unsuccessful (1845) search for the North-West Passage. On return the crew were fêted as heroes and decorated, and shared in a £5000 government bounty: <span class="hlt">Walker</span> was also received by the Queen and (in Ireland) by the Lord Lieutenant, was honoured by the principal British and Irish natural history societies and his portrait was exhibited in the National Portrait Gallery, London. This paper describes his adventurous life, including the Fox Expedition, which from 1862 was spent abroad and included time in the Cariboo gold fields, service in the United States Army, practice in a notorious Californian frontier town and, in later life, the comparative quiet of general and occupational medical practice in Portland, Oregon. Once a household name, his death went unrecorded in the British and Irish medical and lay press. PMID:23143316</p> <div class="credits"> <p class="dwt_author">Froggatt, Peter; Walker, Brian M</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">394</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3813827"> <span id="translatedtitle">Radiographic and functional results in the treatment of early stages of Charcot neuroarthropathy with a <span class="hlt">walker</span> boot and immediate weight bearing</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">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 <span class="hlt">walker</span> 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 <span class="hlt">walker</span> 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.</p> <div class="credits"> <p class="dwt_author">Parisi, Maria Candida Ribeiro; Godoy-Santos, Alexandre Leme; Ortiz, Rafael Trevisan; Sposeto, Rafael Barban; Sakaki, Marcos Hideyo; Nery, Marcia; Fernandes, Tulio Diniz</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">395</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ninds.nih.gov/disorders/dandywalker/dandywalker.htm"> <span id="translatedtitle">Dandy-<span class="hlt">Walker</span> Syndrome</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://medlineplus.gov/">MedlinePLUS</a></p> <p class="result-summary">... at the back of the brain that controls movement) and the fluid-filled spaces around it. The key features ... as unsteadiness, lack of muscle coordination, or jerky movements of the eyes may occur. Other symptoms include increased head ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">396</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUSM.G31A..02H"> <span id="translatedtitle">Geodetic vs. Geologic Measures of Fault Slip Rates in the Northern <span class="hlt">Walker</span> Lane, Basin and Range Province, Western United States</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Quantifying faults slip rates and styles is an important objective in the study of crustal deformation. Fault slip rates are used to quantify seismic hazard associated with active faults, and are an important input into the U.S.G.S. seismic hazard maps. However, when multiple types of data (e.g. geologic, seismic and geodetic) are used to measure slip rates, results from the different techniques can be corroborative, complementary, or in direct conflict. Geologic methods provide some of the only constraints on slip rates of individual faults over hundreds to tens of thousands of years, time scales that are significant with respect to observed deformation patterns, and likely representative of modern hazard. On the other hand geodetic measurements provide strong constraints on the medium to long spatial wavelength (>50 km) budgets of deformation, and on geographic changes in deformation style, and have the potential to provide geographically complete measurements of surface deformation. However, geodetic measurements can be influenced by earthquake cycle effects, e.g. owing to interseismic fault locking and postseismic relaxation, which limit their ability to resolve individual slip rates, especially in complex systems with many closely spaced faults. The northern <span class="hlt">Walker</span> Lane (NWL), in the western Basin and Range Province (BRP) of the United States, is an example of a complex system of dextral, normal and sinestral faults that work together to accommodate approximately 10 mm/yr of relative motion between the Sierra Nevada/Great Valley block and the central part of the BRP. To exploit the strengths of each dataset, we have built a detailed model of NWL crustal blocks and are using geodetic and geologic data to resolve patterns of crustal deformation. We use a block modeling technique that incorporates the strengths of both targeted geologic investigations of slip rates on individual faults and longer wavelength constraints offered by GPS geodesy. To constrain these models we use a compilation of GPS data from our own 163-site MAGNET GPS network plus regional continuous GPS sites from the Plate Boundary Observatory and BARGEN networks, and published USGS campaign velocities. For geologic data we have tabulated slip rate estimates into two categories, 1) published studies with quantitative rates valid in the Quaternary, and 2) the USGS Quaternary Fault and Fold Database that is a comprehensive web-available database with many reconnaissance level estimates of fault slip rate. Our modeling helps unravel the slip rate debate by distinguishing between system-wide discrepancies in integrated moment rate across the NWL, and point-wise discrepancies in individual fault slip rates. Our modeling shows that on the systemic level, even a single reliable geologic slip rate can improve the condition of the modeling, and on the individual fault level geodetic constraints can eliminate feasibility of some very high slip rates allowed by the geologic data. We conclude that for the NWL, the rate disagreement is attributable to an incomplete catalog of geologic slip rates and not to systematic underestimation of slip rates in the individual studies.</p> <div class="credits"> <p class="dwt_author">Hammond, W. C.; Kreemer, C.; Blewitt, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">397</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUFMGP43A0840P"> <span id="translatedtitle">Paleomagnetic Evaluation of Crustal-Scale Block Rotations in the Mina Deflection of the Central <span class="hlt">Walker</span> Lane</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Crustal deformation resulting from relative Pacific-North America plate motion is broadly distributed on faults across the western U.S.. Geodetic observations show that some 25 percent of transform plate motion is currently accommodated by faults east of the Sierra Nevada, from the eastern California shear zone to the central <span class="hlt">Walker</span> Lane (CWL). The northwest trending faults of the CWL are joined to the Furnace Creek - Owens Valley fault system by the Mina deflection, a belt of east-northeast striking faults that serve as a displacement transfer system linking the two fault zones. The Furnace Creek - Owens Valley fault system has a cumulative right-slip of 40 - 50 km, and this displacement is transferred in an extensional right-step to the curved high-angle faults of the Mina deflection. The high-angle fault geometry and basin depths preclude more than 10 km of right-lateral displacement accommodated along structures in the Mina deflection and thus a slip deficit of 30 to 40 km exists. We are attempting to resolve the amount of permanent Neogene strain in the Mina deflection and determine if the geodetically observed strain accumulation and local heterogeneities are consistent with the permanent Neogene strain, in particular, vertical axis rotation of blocks in the Mina deflection area. To in part quantify the magnitude and potential heterogeneities of crustal block rotation and to more clearly define block boundaries, paleomagnetic data have been obtained from numerous stratigraphic sections of upper Tertiary volcanic rocks in a 300 sqkm area centered on the Candeleria Hills, NV. Eight to ten oriented samples from 260 sites distributed across multiple tectonic blocks have been fully demagnetized with all sites yielding interpretable results (23 sites (two sections) in mid Miocene andesite flows, 102 sites (10 sections) in upper Miocene basalt flows, and 135 sites (27 sections) in lower Miocene, regionally extensive ash flow tuffs). Although some anomalous directions were observed, the stratigraphically corrected (typically less than 15° dip) data from the volcanic rocks are internally consistent, well-grouped at the site level, and discordant clockwise to late Cenozoic expected field direction (358\\deg, 58\\deg). For example, a Miocene basalt flow section in the central Candelaria Hills yields a group mean (D = 16.5, I = 50.0, a95 = 1.8, k = 497.3) that provides an inferred rotation of +18.5\\deg +/- 6.9\\deg compared to a late Cenozoic expected field. Two sites in the Candelaria Junction regional ash flow tuff located in separate structural blocks yield similar inclinations, yet statistically distinct declinations (Site1, 255.8, -48.6, 4.4; Site2, 296.4, -41.0, 4.6), providing evidence for a modest clockwise vertical axis rotation between structural blocks. Overall, we interpret most data obtained to reflect at most moderate clockwise vertical axis rotation among structural blocks in the Mina deflection region. The absence of large magnitude rotation of any individual block and, thus between blocks, places limits on the amount of cumulative slip on fault networks in the Mina deflection. The area may be accommodating strain by net northwest extension on a curved fault array with very low rates of vertical axis rotation and minor slip on individual faults. To compare the geodetic observations with long-term strain, we are developing a tectonic model, using existing fault geometries and paleomagnetic data for the CWL that links vertical axis rotations of the fragmented upper crust to the driving mechanisms associated with slip transfer across the region.</p> <div class="credits"> <p class="dwt_author">Petronis, M. S.; Geissman, J. W.; Oldow, J. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">398</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51148168"> <span id="translatedtitle">Nonlinear structure of escape-times to falls for a passive dynamic <span class="hlt">walker</span> on an irregular slope: Anomaly detection using multi-class support vector machine and latent state extraction by canonical correlation analysis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Falls that occur during walking are a significant problem from the viewpoints of both medicine and robotics engineering. It is very important to predict falls in order to prevent the falls or minimize the ensuing damage from them. In this study, we investigate the structure of the escape-times from walking to falling of a passive dynamic biped <span class="hlt">walker</span> on a</p> <div class="credits"> <p class="dwt_author">Hiromichi Suetani; Aiko M. Ideta; Jun Morimoto</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">399</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/42536812"> <span id="translatedtitle">Estimating the economic injury level and the economic threshold for the use of 𝛂-cypermethrin against the sugarcane borer, Eldana saccharina <span class="hlt">Walker</span> (Lepidoptera: Pyralidae)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Five years of data from insecticide trials that assessed the value of using ?-cypermethrin (Fastac®) against the sugarcane borer Eldana saccharina <span class="hlt">Walker</span> (Lepidoptera: Pyralidae) were used to estimate the economic injury level (EIL) and the economic threshold (ET) for this pest. The analysis was based on estimates of borer damage (percentage of internodes bored) and larval numbers, and the effect</p> <div class="credits"> <p class="dwt_author">Graeme W. Leslie</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">400</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFMGP44A..04R"> <span id="translatedtitle">Rates and timing of vertical-axis block rotations across the Sierra Nevada-<span class="hlt">Walker</span> Lane transition in the Bodie Hills</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotation across the Sierra Nevada-<span class="hlt">Walker</span> Lane transition in the Bodie Hills, California/Nevada. In zones of continental deformation, block rotations are an important mechanism for permanent stain accommodation, and thus may be crucial to testing geodetic block models and resolving geologic-geodetic slip discrepancies. In our study, data included in the paleomagetic site means are high quality AF demagnetization results (least squared fits that generally include 5-7 points with MAD values less than 1). Thermal demagnetization results match the AF directions, and both thermal demag and rockmag results indicate strong ChRM, mostly carried by single domain magnetite. The site means used to calculate the VGPs all have a95 values less than 10 (mostly 2-5) and include 6-11 sites each. Each site (and thus site mean) has a reasonably well-known structural correction. The VGP scatter values range from 12 to 16 degrees, indicating that they include appropriate secular variation. The mean declinations and 95 percent confidence limits for each VGP timeslice are statistically distinct from one another (71 ± 9, 39 ± 13, and 11 ± 11 degrees). The slope of a linear regression fit to the age versus declination data gives a rate of vertical axis block rotation of approximately 3-4 degrees/Myr. Fitting two separate lines to the age vs. declination data would indicate an increase in the rates of rotation since ~10 Ma. Two possible interpretations of the data are: (1) the rotations began during or before the Middle Miocene, or (2) rates of rotation were high initially (e.g. ~10 Ma) and decelerated until the Pliocene. These data have implications for the (1) timing and spatial extent of distributed strain accumulation related to the initiation of the San Andreas Fault-Eastern California Shear Zone-<span class="hlt">Walker</span> Lane transform plate boundary, (2) transfer of transform plate boundary deformation into the maturing <span class="hlt">Walker</span> Lane, and (3) the initiation of transtensional block rotations and bounding fault systems.</p> <div class="credits"> <p class="dwt_author">Rood, D. H.; Herman, S.; Burbank, D.; Bogue, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_19");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a 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Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_20");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a style="font-weight: bold;">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_22");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">401</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AGUFM.G23D..06K"> <span id="translatedtitle">Geodetic Constraints on the Rigidity and Eastern Boundary of the Sierra Nevada Micro-Plate, from Mohawk Valley to Southern <span class="hlt">Walker</span> Lane</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Sierra Nevada - Great Valley (SNGV) micro-plate has long been recognized as a tectonically rigid, though mobile, entity within the Pacific - North America plate boundary zone. The motion of the SNGV relative to stable North America (and the Colorado Plateau) provides the kinematic boundary condition for, and perhaps drives, the deformation in the Basin and Range Province (BRP) and <span class="hlt">Walker</span> Lane. In the north the motion of the SNGV is aligned with the Mohawk Valley fault zone, which could have a slip rate of over a few mm/yr. The crest of the Sierras marks the SNGV’s eastern edge, but the obliquity between orientation of this boundary and the block’s motion implies an expected increase in rangefront-normal extension from the northern to southern <span class="hlt">Walker</span> Lane. We use new GPS data from the EarthScope Plate Boundary Observatory (PBO) and our own semi-continuous MAGNET network to revisit the following questions: 1) Do the data still support rigidity of the SNGV?; 2) How far east does the rigidity extend and how does this relate to SNGV lithology?; 3) How does the direction of SNGV motion relate to the strike of its eastern margin and observed strain partitioning (and its along strike variation) in the <span class="hlt">Walker</span> Lane?; and 4) How is SNGV-BRP motion accommodated between the <span class="hlt">Walker</span> Lane and the Cascadia forearc? We analyze data from all the available continuous GPS sites in the greater SNGV region, including new data from PBO, as well as data from MAGNET. All data are processed with the GIPSY-OASIS II precise point positioning software using recently reprocessed orbits from JPL's IGS Analysis Center. The processing includes satellite and station antenna calibrations and all data have the phase ambiguities fixed using the Ambizap algorithm. Positions are estimated in our custom-made North America reference frame in which continental-scale common-mode errors are removed. Velocities and uncertainties are estimated using the CATS software in which we assuming an error model with flicker plus white noise. Many stations in the Great Valley show anomalous horizontal motions compared to the most stable stations in the Sierra Nevada Mountains. These motions are likely due to hydrological effects in the Great Valley, which can be seen in the significant subsidence that occurs at these stations. Consequently, there are a relatively small number of stations that should be used to constrain the SNGV rigid body rotation. We find that stations in the southernmost Sierra Nevada Mountains have a northward motion of >1 mm/yr relative to the central and northern Sierras. This could partly be explained in terms of regional post-seismic viscoelastic relaxation from recent earthquakes (e.g. Kern County 1952, Landers, 1992, Hector Mine1999), but may also reflect the region’s anomalous mantle dynamics.</p> <div class="credits"> <p class="dwt_author">Kreemer, C. W.; Hammond, W. C.; Blewitt, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">402</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/2509092"> <span id="translatedtitle">Reduction of nitromin to nitrogen mustard: unscheduled DNA synthesis in aerobic or anaerobic rat hepatocytes, JB1, BL8 and <span class="hlt">Walker</span> carcinoma cell lines.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A novel route for the microsomal generation of nitrogen mustard from its N-oxide nitromin is demonstrated. The mustard was trapped as an adduct with diethyldithiocarbamate and estimated by capillary GLC. The enzyme responsible for this reduction could utilize either NADPH or NADH. Reduction occurred preferentially under anaerobic conditions. Purified cytochrome P450 reductase could carry out this reaction. Similar activities were seen using microsomal fractions from rat liver or liver derived BL8, JB1 or <span class="hlt">Walker</span> 256 carcinoma cells, when these were expressed on a per mg of protein basis. Unscheduled DNA synthesis (UDS) was used as an index of activation of nitromin in these cell systems. In all instances, greater induction of UDS occurred in cells incubated with nitromin under anaerobic conditions. PMID:2509092</p> <div class="credits"> <p class="dwt_author">White, I N; Suzanger, M; Mattocks, A R; Bailey, E; Farmer, P B; Connors, T A</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">403</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/760276"> <span id="translatedtitle">[Influence of local hyperthermia induced by micro-waves and X-rays on the <span class="hlt">Walker</span> carcinoma of the rat (author's transl)].</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The authors studied the influence on the solid <span class="hlt">Walker</span> carcinoma in the rat exerted by a slight local hyperthermia induced by micro-waves, which was applied alone and combined with X-ray irradiations. It could be demonstrated that the tumor has the same temperature as the sub-peritoneal region. Thus the final temperature reached by the treatment with micro-waves can be exactly controlled. Heating up to 41 degrees C for 30 minutes produces an increase of the survival rate of animals with tumors of 2 to 6 grams from 17% to 27%, whereas the healing rate is 57% after an X-ray irradiation with 1130 rad and 75% after the combined treatment. Each of the three therapy methods produces a significant prolongation of the survival time of the dying animals. The disadvantages of an anisologic tumor-host system are discussed on the basis of the results achieved. PMID:760276</p> <div class="credits"> <p class="dwt_author">Brückner, V; Zywietz, F; Jung, H</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">404</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24018189"> <span id="translatedtitle">Natural-product-based insecticidal agents 14. Semisynthesis and insecticidal activity of new piperine-based hydrazone derivatives against Mythimna separata <span class="hlt">Walker</span> in vivo.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">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 <span class="hlt">Walker</span> in vivo. Especially compounds 6b, 6i and 6r, the final mortality rates of which, at the concentration of 1mg/mL, were 62.1%, 65.5% and 65.5%, respectively, exhibited more pronounced insecticidal activity compared to toosendanin at 1mg/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</p> <div class="credits"> <p class="dwt_author">Qu, Huan; Yu, Xiang; Zhi, Xiaoyan; Lv, Min; Xu, Hui</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-08-20</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">405</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/20432602"> <span id="translatedtitle">Process evaluation of the project P.A.T.H.S. (secondary 2 program): findings based on the co-<span class="hlt">walker</span> scheme.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">To understand the implementation quality of the Tier 1 Program (Secondary 2 Curriculum) of the P.A.T.H.S. Project, process evaluation was carried out by co-<span class="hlt">walkers</span> through classroom observation of 195 units in 131 schools. Results showed that the overall level of program adherence was generally high with an average of 84.55%, and different factors of the implementation process were evaluated as positive. Quality of program implementation and achievement of program objectives were predicted by students' participation and involvement, strategies to enhance students' motivation, opportunity for reflection, time management, and class preparation. Success in program implementation was predicted by students' participation and involvement, classroom control, interactive delivery method, strategies to enhance students' motivation, opportunity for reflection, and lesson preparation. PMID:20432602</p> <div class="credits"> <p class="dwt_author">Shek, Daniel T L; Tam, Suet-yan</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">406</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6659697"> <span id="translatedtitle"><span class="hlt">Walker</span> Gilmore: a stratified Woodland period occupation in eastern Nebraska. A report of the 1968 excavations. Final report 1968-83</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Excavations at <span class="hlt">Walker</span> 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.</p> <div class="credits"> <p class="dwt_author">Haas, D.R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">407</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFM.G53C..04B"> <span id="translatedtitle">Resolving the discrepancy between geodetic and geologic estimates of fault slip rates in the central <span class="hlt">Walker</span> Lane: A block modeling approach</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">Walker</span> Lane is a ~100 km wide zone of active intracontinental transtensional faulting which accommodates 8-10 mm/yr of Pacific-North American relative dextral plate motion between the northwest translating Sierra Nevada/Great Valley microplate and the west-northwestward extending Basin and Range in the western United States. Between the <span class="hlt">Walker</span> Lake and Lake Tahoe basins (~38.5-39.5° N latitude), the <span class="hlt">Walker</span> Lane lacks strike-slip faults optimally oriented to accommodate northwest-directed dextral shear. In this region, geologic studies of active faulting show that Quaternary tectonic deformation occurs in a northwest-trending series of north-striking, normal fault-bounded basins. Geomorphic and paleoseismic studies of the major basin-bounding faults estimate normal slip rates between ~0.3-2.5 mm/yr. However, the combined geologically determined slip rates for major faults in the central <span class="hlt">Walker</span> Lane are not sufficient to accommodate the geodetically observed northwest-directed dextral shear. To address this discrepancy, we model crustal deformation using GPS data from the EarthScope Plate Boundary Observatory and other continuous GPS networks together with data from UNR's semi-continuous network MAGNET. We estimate rates of fault slip and vertical axis block rotation using an elastic block model. Comparisons between geodetically and geologically estimated slip rates on the major basin-bounding normal faults show that 7 out of 8 geodetic estimates agree with geologic estimates to within uncertainties. However, models constrained solely by GPS data predict dextral slip rates on the basin-bounding normal faults that are greater than or equal to the normal slip rates, between 0.3-2.0 mm/yr. This prediction is not substantiated by paleoseismic and geomorphic fault studies, suggesting a discrepancy between the geologic and geodetic datasets. Block models that are forced to strictly adhere to geologically observed fault slip style constraints (i.e. no oblique slip on normal faults) predict clockwise vertical axis rotations for normal fault-bounded blocks between 1-4.5°/My, which are double the rates predicted by the GPS-based model. The resulting RMS residual velocities are significantly larger than the best fitting geodetic model, indicating a poor fit to the GPS data. Models that loosely impose geologic style constraints predict small amounts of oblique shear on normal faults and somewhat increased rates of clockwise vertical axis block rotation. These models result in RMS residual velocities only slightly larger than the best fitting geodetic model. This research suggests that resolution between the two datasets may lie in the combination of low magnitude oblique dextral slip on basin-bounding normal faults with clockwise vertical axis rotations of normal fault bounded blocks.</p> <div class="credits"> <p class="dwt_author">Bormann, J. M.; Hammond, W. C.; Kreemer, C. W.; Wesnousky, S. G.; Blewitt, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">408</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24036940"> <span id="translatedtitle">Tumor growth reduction is regulated at the gene level in <span class="hlt">Walker</span> 256 tumor-bearing rats supplemented with fish oil rich in EPA and DHA.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We investigated the effect of fish oil (FO) supplementation on tumor growth, cyclooxygenase 2 (COX-2), peroxisome proliferator-activated receptor gamma (PPAR?), and RelA gene and protein expression in <span class="hlt">Walker</span> 256 tumor-bearing rats. Male Wistar rats (70 days old) were fed with regular chow (group W) or chow supplemented with 1 g/kg body weight FO daily (group WFO) until they reached 100 days of age. Both groups were then inoculated with a suspension of <span class="hlt">Walker</span> 256 ascitic tumor cells (3×107 cells/mL). After 14 days the rats were killed, total RNA was isolated from the tumor tissue, and relative mRNA expression was measured using the 2-??CT method. FO significantly decreased tumor growth (W=13.18±1.58 vs WFO=5.40±0.88 g, P<0.05). FO supplementation also resulted in a significant decrease in COX-2 (W=100.1±1.62 vs WFO=59.39±5.53, P<0.001) and PPAR? (W=100.4±1.04 vs WFO=88.22±1.46, P<0.05) protein expression. Relative mRNA expression was W=1.06±0.022 vs WFO=0.31±0.04 (P<0.001) for COX-2, W=1.08±0.02 vs WFO=0.52±0.08 (P<0.001) for PPAR?, and W=1.04±0.02 vs WFO=0.82±0.04 (P<0.05) for RelA. FO reduced tumor growth by attenuating inflammatory gene expression associated with carcinogenesis. PMID:24036940</p> <div class="credits"> <p class="dwt_author">Borghetti, G; Yamazaki, R K; Coelho, I; Pequito, D C T; Schiessel, D L; Kryczyk, M; Mamus, R; Naliwaiko, K; Fernandes, L C</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-08-30</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">409</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24053441"> <span id="translatedtitle">Conserved <span class="hlt">Walker</span> A Cysteines 431 and 1074 in Human P-Glycoprotein Are Accessible to Thiol-Specific Agents in the Apo and ADP-Vanadate Trapped Conformations.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">P-Glycoprotein (P-gp) is an ATP-binding cassette efflux transporter involved in the development of multidrug resistance in cancer cells. Although the mechanism of P-gp efflux has been extensively studied, aspects of its catalytic and transport cycle are still unclear. In this study, we used conserved C431 and C1074 in the <span class="hlt">Walker</span> A motif of nucleotide-binding domains (NBDs) as reporter sites to interrogate the interaction between the two NBDs during the catalytic cycle. Disulfide cross-linking of the C431 and C1074 residues in a Cys-less background can be observed in the presence of M14M and M17M cross-linkers, which have spacer arm lengths of 20 and 25 Å, respectively. However, cross-linking with both cross-linkers was prevented in the ADP-vanadate trapped (closed) conformation. Both C431 and C1074 alone or together (double mutant) in the apo and closed conformations were found to be accessible to fluorescein 5-maleimide (FM) and methanethiosulfonate derivatives of rhodamine and verapamil. In addition, C1074 showed 1.4- and 2-fold higher degrees of FM labeling than C431 in the apo and closed conformations, respectively, demonstrating that C1074 is more accessible than C431 in both conformations. In the presence of P-gp substrates, cross-linking with M17M is still observed, suggesting that binding of substrate in the transmembrane domains does not change the accessibility of the cysteines in the NBDs. In summary, the cysteines in the <span class="hlt">Walker</span> A motifs of NBDs of human P-gp are differentially accessible to thiol-specific agents in the apo and closed conformations. PMID:24053441</p> <div class="credits"> <p class="dwt_author">Sim, Hong-May; Bhatnagar, Jaya; Chufan, Eduardo E; Kapoor, Khyati; Ambudkar, Suresh V</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-04</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">410</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/1081454"> <span id="translatedtitle">Numerical simulations of depressurization-induced gas production from gas hydrate reservoirs at the <span class="hlt">Walker</span> Ridge 312 site, northern Gulf of Mexico</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">In 2009, the Gulf of Mexico (GOM) Gas Hydrates Joint-Industry-Project (JIP) Leg II drilling program confirmed that gas hydrate occurs at high saturations within reservoir-quality sands in the GOM. A comprehensive logging-while-drilling dataset was collected from seven wells at three sites, including two wells at the <span class="hlt">Walker</span> Ridge 313 site. By constraining the saturations and thicknesses of hydrate-bearing sands using logging-while-drilling data, two-dimensional (2D), cylindrical, r-z and three-dimensional (3D) reservoir models were simulated. The gas hydrate occurrences inferred from seismic analysis are used to delineate the areal extent of the 3D reservoir models. Numerical simulations of gas production from the <span class="hlt">Walker</span> Ridge reservoirs were conducted using the depressurization method at a constant bottomhole pressure. Results of these simulations indicate that these hydrate deposits are readily produced, owing to high intrinsic reservoir-quality and their proximity to the base of hydrate stability. The elevated in situ reservoir temperatures contribute to high (5–40 MMscf/day) predicted production rates. The production rates obtained from the 2D and 3D models are in close agreement. To evaluate the effect of spatial dimensions, the 2D reservoir domains were simulated at two outer radii. The results showed increased potential for formation of secondary hydrate and appearance of lag time for production rates as reservoir size increases. Similar phenomena were observed in the 3D reservoir models. The results also suggest that interbedded gas hydrate accumulations might be preferable targets for gas production in comparison with massive deposits. Hydrate in such accumulations can be readily dissociated due to heat supply from surrounding hydrate-free zones. Special cases were considered to evaluate the effect of overburden and underburden permeability on production. The obtained data show that production can be significantly degraded in comparison with a case using impermeable boundaries. The main reason for the reduced productivity is water influx from the surrounding strata; a secondary cause is gas escape into the overburden. The results dictate that in order to reliably estimate production potential, permeability of the surroundings has to be included in a model.</p> <div class="credits"> <p class="dwt_author">Myshakin, Evgeniy M.; Gaddipati, Manohar; Rose, Kelly; Anderson, Brian J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">411</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUFM.G31D..07H"> <span id="translatedtitle">Crustal Deformation across the Sierra Nevada-Northern <span class="hlt">Walker</span> Lane, Basin and Range Transition, Western United States Measured with GPS, 2000-2004</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In the northern <span class="hlt">Walker</span> Lane (WL) of northwest Nevada and northeast California, approximately 20-25% of the contemporary Pacific/North America relative plate motion is accommodated east of the Sierra Nevada in a focused zone of dextral shear and extension. Previous measurements with the Global Positioning System (GPS) have identified a partitioning of shear and extension and a widening of the zone of active deformation north of 39? north latitude. This deformation pattern may indicate that northwest-directed extension in the Basin and Range east of the WL becomes more active northward, making up for a northward decrease in northwest-directed dextral slip on the WL strike slip faults. Alternatively (or additionally), it may be an effect of postseismic relaxation following the 20th century earthquakes in the Central Nevada Seismic Belt (CNSB), east of the WL. We present velocities and strain rate tensors obtained from newly collected GPS data along networks that extend from the Central Great Valley of California, across the Sierra Nevada, <span class="hlt">Walker</span> Lane and into the central Basin and Range province. Campaign surveys in September 2000 and September 2004 occupied 56 sites that have greater spatial density (<20 km), and lie outside the footprint of the planned deployment of the Plate Boundary Observatory Extension/Backbone continuous GPS cluster. These networks fill gaps in previous GPS coverage, and between the sparsely (near 100 km) spaced continuously recording Basin and Range Geodetic Network (BARGEN), whose data we include in our GIPSY/OASIS II processing. Additionally, our solution will include GPS data from 40+ stations of a new network of semi-continuous sites: the Nevada Mobile Array of GPS for Nevada Transtension (MAGNET), which commenced operation the end of January 2004 and currently has <1 year of data, but provides a complementary spatial distribution of sites and will, in future, greatly enhance constraint on WLB surface deformation. We will use the combined solution to provide new constraints on postseismic relaxation on the CNSB and on plate boundary kinematics in the northern WL.</p> <div class="credits"> <p class="dwt_author">Hammond, W. C.; Thatcher, W.; Blewitt, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">412</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/35784561"> <span id="translatedtitle">An autosomal recessive limb girdle muscular dystrophy (LGMD2) with mild mental retardation is allelic to <span class="hlt">Walker</span>–Warburg syndrome (WWS) caused by a mutation in the POMT1 gene</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Mutations of the protein O-mannosyltransferase (POMT1) gene affect glycosylation of ?-dystroglycan, leading to <span class="hlt">Walker</span>–Warburg syndrome, a lethal disorder in early life with severe congenital muscular dystrophy, and brain and eye malformations. Recently, we described a novel form of recessive limb girdle muscular dystrophy with mild mental retardation, associated with an abnormal ?-dystroglycan pattern in the muscle, suggesting a glycosylation defect.</p> <div class="credits"> <p class="dwt_author">Burcu Balci; Gökhan Uyanik; Pervin Dincer; Claudia Gross; Tobias Willer; Beril Talim; Göknur Haliloglu; Gülsev Kale; Ute Hehr; Jürgen Winkler; Haluk Topalo?lu</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">413</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/37111574"> <span id="translatedtitle">Syndrome of microcephaly, Dandy-<span class="hlt">Walker</span> malformation, and Wilms tumor caused by mosaic variegated aneuploidy with premature centromere division (PCD): report of a new case and review of the literature</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We report a male infant with multiple congenital anomalies and mosaic variegated aneuploidy; a rare cytogenetic abnormality\\u000a characterized by mosaicism for several different aneuploidies involving many different chromosomes. He had prenatal-onset\\u000a growth retardation, microcephaly, dysmorphic face, seizures, hypotonia, feeding difficulty, and developmental delay. In addition,\\u000a he developed bilateral Wilms tumors. Neuroradiological examination revealed Dandy-<span class="hlt">Walker</span> malformation and hypoplasia of the\\u000a cerebral</p> <div class="credits"> <p class="dwt_author">Hiroshi Kawame; Yoko Sugio; Yuichi Fuyama; Yoshihiro Hayashi; Hideaki Suzuki; Kenji Kurosawa; Kihei Maekawa</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">414</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.esd.ornl.gov/people/mulholland/pubs/Mulholland%202004%20Biogeochemistry_vol70_pages403-426.pdf"> <span id="translatedtitle">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 <span class="hlt">Walker</span> Branch Watershed</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Long-term, weekly measurements of streamwater nitrogen and phosphorus concentrations in the West Fork of <span class="hlt">Walker</span> 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</p> <div class="credits"> <p class="dwt_author">Patrick J. Mulholland</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">415</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/7697757"> <span id="translatedtitle">Genotoxic effects of 3-amino-1,2,4-benzotriazine-1,4-dioxide (SR 4233) and nitrogen mustard-N-oxide (nitromin) in <span class="hlt">Walker</span> carcinoma cells under aerobic and hypoxic conditions.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">As judged by alkaline elution, exposure of <span class="hlt">Walker</span> cells to either 3-amino-1,2,4-benzotriazine-1,4-dioxide (SR 4233) or nitromin results in a dose-dependent increase in DNA damage due to single-strand breaks. With nitromin or SR 4233 there was little difference in the extent of DNA single-strand breaks between <span class="hlt">Walker</span> cells incubated either hypoxically or aerobically. In contrast, there was a 24-fold enhancement in the differential hypoxic/aerobic response to SR 4233 in clonogenic studies. Following incubation of cells with nitrogen mustard, DNA cross-linking is observed. Bioreduction of nitromin would be expected to yield nitrogen mustard as the putative reactive metabolite. However, only DNA strand-breaks could be detected in <span class="hlt">Walker</span> cells incubated with nitromin, suggesting that reduction of this pro-drug to nitrogen mustard was not a major activation pathway. In cells incubated under aerobic conditions, SR 4233 induces oxidative DNA damage, as indicated by the formation of 8-hydroxydeoxyguanosine, suggesting the involvement of futile redox cycling. In rats dosed with SR 4233 in vivo, significantly higher levels of 8-hydroxydeoxyguanosine could be detected in liver, compared to vehicle-dosed controls. PMID:7697757</p> <div class="credits"> <p class="dwt_author">Cahill, A; Jenkins, T C; Pickering, P; White, I N</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-03-30</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">416</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/19114047"> <span id="translatedtitle">Heterorhabditis sonorensis n. sp. (Nematoda: Heterorhabditidae), a natural pathogen of the seasonal cicada Diceroprocta ornea (<span class="hlt">Walker</span>) (Homoptera: Cicadidae) in the Sonoran desert.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A new Heterorhabditis species was isolated from nymphal stages of the seasonal cicada Diceroprocta ornea (<span class="hlt">Walker</span>) in an asparagus field in the state of Sonora, Mexico. Concomitantly, another isolate of the same nematode species was also collected from an oak woodland habitat in the Chiricahua mountain range in southeastern Arizona. Morphological and molecular studies together with cross-hybridization tests indicate these two isolates are conspecific and represent a new undescribed Heterorhabditis sp. This new species is distinguished from other species in this genus by a combination of several qualitative and quantitative morphological traits. Key diagnostic features include: presence of a pronounced post-anal swelling in the hermaphrodite; male with nine pairs of bursal rays, with pairs 4 and 7 bent outwards and one pair of papillae placed on the cloacal opening, value of D% (average: 79); infective juveniles with a well developed cuticular tooth, long tail (average: 105mum) and values of D% (average: 90) and E% (average: 99). In addition to these diagnostic characters, cross-hybridization tests between the new species with H. bacteriophora and H. mexicana yielded no fertile progeny. Comparison of ITS rDNA sequences with other available sequences of described species depicted the two isolates as a new species. Phylogenetic analysis of these sequence data placed H. sonorensis n. sp. as a member of the indica-group. PMID:19114047</p> <div class="credits"> <p class="dwt_author">Stock, S Patricia; Rivera-Orduño, Benjamin; Flores-Lara, Yolanda</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-11</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">417</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2266935"> <span id="translatedtitle">Metabolic and morphological alterations induced by proteolysis-inducing factor from <span class="hlt">Walker</span> tumour-bearing rats in C2C12 myotubes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Background Patients with advanced cancer suffer from cachexia, which is characterised by a marked weight loss, and is invariably associated with the presence of tumoral and humoral factors which are mainly responsible for the depletion of fat stores and muscular tissue. Methods In this work, we used cytotoxicity and enzymatic assays and morphological analysis to examine the effects of a proteolysis-inducing factor (PIF)-like molecule purified from ascitic fluid of <span class="hlt">Walker</span> tumour-bearing rats (WF), which has been suggested to be responsible for muscle atrophy, on cultured C2C12 muscle cells. Results WF decreased the viability of C2C12 myotubes, especially at concentrations of 20–25 ?g.mL-1. There was an increase in the content of the pro-oxidant malondialdehyde, and a decrease in antioxidant enzyme activity. Myotubes protein synthesis decreased and protein degradation increased together with an enhanced in the chymotrypsin-like enzyme activity, a measure of functional proteasome activity, after treatment with WF. Morphological alterations such as cell retraction and the presence of numerous cells in suspension were observed, particularly at high WF concentrations. Conclusion These results indicate that WF has similar effects to those of proteolysis-inducing factor, but is less potent than the latter. Further studies are required to determine the precise role of WF in this experimental model.</p> <div class="credits"> <p class="dwt_author">Yano, Claudia L; Ventrucci, Gislaine; Field, William N; Tisdale, Michael J; Gomes-Marcondes, Maria Cristina C</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">418</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/7540609"> <span id="translatedtitle">Osteoporosis-like changes in <span class="hlt">Walker</span> carcinoma 256-bearing rats, not accompanied with hypercalcemia or parathyroid hormone-related protein production.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Walker</span> carcinoma 256 (W256) was reported to induce hypercalcemia dependent on bone metastasis and/or parathyroid hormone-related protein (PTHrP) in the rat, providing a model of the humoral hypercalcemia of malignancy. In this study, after the subcutaneous inoculation of cells of the W256/S line, which is maintained in this laboratory, into young female Wistar Imamichi rats (6 weeks old), serum calcium and phosphorus levels changed only within the control range, whereas serum alkaline phosphatase activity and urinary calcium level significantly increased and urinary phosphorus decreased during the tumor growth, resulting in hypercalciuria and hypophosphaturia. W256/S did not express PTHrP-mRNA, whereas LLC-W256 cells did express it. Serum PTHrP level was not changed in W256/S-bearing rats. Osteoporosis-like changes, bone weight loss, low contents of bone calcium and phosphorus, and a decrease in the bone mineral density (BMD), were observed in the femur 14 days after the tumor inoculation. There was a pronounced decrease in the serum 17 beta-estradiol level during the tumor growth. The reduction of BMD of femurs in W256/S-bearing rats was significantly inhibited by treatment with salmon calcitonin or 17 beta-estradiol. On the basis of these results, W256/S carcinoma-bearing rats seem to be a useful model for osteoporosis of hypoovarianism. PMID:7540609</p> <div class="credits"> <p class="dwt_author">Waki, Y; Miyamoto, K; Kasugai, S; Ohya, K</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">419</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/6469274"> <span id="translatedtitle">Establishment and characterization of cell lines from the <span class="hlt">Walker</span> carcinoma 256 able to grow in suspension culture and deficient in thymidine kinase.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A cell line from the <span class="hlt">Walker</span> carcinosarcoma 256 of the rat has been established in suspension culture in medium with 5% bovine calf serum for over 350 generations, with an average population doubling time of 17 h, a plating efficiency of 56%, a colony forming efficiency of 32%, and a good capacity to form colonies in soft agar. The cells are morphologically indistinguishable from those in the solid tumor and ascites as checked by transmission and scanning electron microscopy. The karyotype is characterized by a modal number of 65 chromosomes and by the presence of a marker metacentric chromosome. The cells express thymidine kinase, gamma-glutamyl transpeptidase, and alkaline phosphatase; are agglutinable by concanavalin A; and can be synchronized by the triple thymidine block. They induce primary tumors, both subcutaneously (solid) and intraperitoneally (ascitic), in the rat; are able to metastasize upon injection by the tail vein; and invade the chorioallantoic membrane of the chick embryo. Cells in suspension can be transferred to monolayers, considerably decreasing their tumorigenicity without affecting the other parameters studied, and can be switched back to suspension culture. DNA-mediated transfection showed that DNA from these cells can transform the NIH-3T3 line. Upon growth of the monolayers in a BrdUr-containing medium, a sub-line was established that was cloned into a thymidine kinase-deficient line unable to grow in HAT medium and with properties otherwise similar to those of the parental wild type cells. PMID:6469274</p> <div class="credits"> <p class="dwt_author">Arvelo, F; Yabrudi, A; Delgado, M E; González-Cadavid, N</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">420</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/3045"> <span id="translatedtitle">[Biochemical investigations of cancer cachexia. II. Depletion of glycogenolysis and stimulation of gluconeogenesis in <span class="hlt">Walker</span> carcinoma 256 bearing rats (author's transl)].</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">150-200 g heavy, <span class="hlt">Walker</span>-carcinoma bearing, male Sprague-Dawley-rats showed rapid, tumour weight dependent, loss of liver glycogen until complete depletion in tumour groups heavier than 40 g/animal. Simultaneously the glycogen mobilization after massive glucagon stimulation, was successivly diminished and finally abolished in different groups with increasing tumor weight. Concomitantly the spontaneous and stimulated activity of liver phosphorylase a was found markedly reduced in advanced tumour cachexia, the extent of stimulation of liver phosphorylase a activity by intracardial injections of epinephrine not being altered. Tumour induced inhibition of glycogen mobilization thus appears to have been excluded. To account for the relative late pronounced hypoglycemia in peripherial rat blood in face of the early loss of liver glycogen, accelerated gluconeogenesis has been postulated. In accord with this spontaneous rise in liver tyrosine amino transferase was found in tumour bearing rats along with a doubled maximal stimulation value after medrol injection as compared to control groups. This behavior could not be shown for liver alanine aminotransferase and liver fructose 1,6-di-phosphatase. The former showed no differences between control and tumour groups neither of spontaneous nor of stimulated activity. The latter showed only a very reluctant rise after massive stimulation by triamcinolone for 3 days in the control groups, the tumour bearing groups showing no deviation from spontaneous control values. PMID:3045</p> <div class="credits"> <p class="dwt_author">Schulze, B; Buchelt, L; Dittmann, H W; Mensch, K W</p> <p class="dwt_publisher"></p> <p class="publishDate">1976-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_20");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">421</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2843139"> <span id="translatedtitle">FOXC1 is required for normal cerebellar development and is a major contributor to chromosome 6p25.3 Dandy-<span class="hlt">Walker</span> malformation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Dandy-<span class="hlt">Walker</span> 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.</p> <div class="credits"> <p class="dwt_author">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</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">422</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24064451"> <span id="translatedtitle">Isolation and Identification of Two Novel Attractant Compounds from Chinese Cockroach (Eupolyphaga sinensis <span class="hlt">Walker</span>) by Combination of HSCCC, NMR and CD Techniques.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">High-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of n-hextane-ethyl acetate-methanol-water (1.5:1:1.5:1, v/v/v/v) was applied to the isolation and purification of attractants from Chinese cockroach, Eupolyphaga sinensis <span class="hlt">Walker</span>. Two new attractants with attractant activity towards the male insects were obtained from the extract sample in a one-step separation. Their purities were determined by HPLC. Subsequent MS, NMR and CD analyses have led to the characterization of (R)-3-ethyl-6,8-dihydroxy-7-methyl-3,4-dihydroisochromen-1-one (1) and (R)-6,8-dihydroxy-3,7-dimethyl-3,4-dihydroisochromen-1-one (2), two novel isocumarin type attractants. Based on these results, it is concluded that HSCCC is a viable separation method option for purifying insect attractants, while effectively maintaining the attracting activity of the isolates. This is the first attempt to apply counter-current chromatography technique to separate attractants from Chinese cockroach. PMID:24064451</p> <div class="credits"> <p class="dwt_author">Jiang, Wei; Wu, Xiaodan; Wu, Bin</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-13</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">423</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1854960"> <span id="translatedtitle">Expression of the Murine Pomt1 Gene in Both the Developing Brain and Adult Muscle Tissues and Its Relationship with Clinical Aspects of <span class="hlt">Walker</span>-Warburg Syndrome</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Walker</span>-Warburg syndrome (WWS) is the most severe of a group of congenital disorders that have in common defects in the O-glycosylation of ?-dystroglycan. WWS is characterized by congenital muscular dystrophy coupled with severe ocular and brain malformations. Moreover, in at least one-fifth of the reported cases, mutations in the POMT1 gene are responsible for this disease. During embryonic development (E8.5 to E11.5), the mouse Pomt1 gene is expressed in the tissues most severely affected in WWS, the muscle, eye, and brain. In this study, we show that mPomt1 expression is maintained in the muscle and eye in later developmental stages and, notably, that its expression is particularly strong in regions of brain and cerebellum that, when affected, could generate the defects observed in patients with WWS. We show that the Pomt1 protein is localized to the sarcoplasmic reticulum of muscle tissue cells in adult mice, where ?-dystroglycan is O-glycosylated. Furthermore, the Pomt1 protein is localized to the acrosome of maturing spermatids, where ?-dystroglycan is not glycosylated, so that Pomt1 might have a different target for O-mannosylation in the testes. This expression pattern in the testes could also be related to the gonadal anomalies observed in some patients with WWS.</p> <div class="credits"> <p class="dwt_author">Prados, Belen; Pena, Almudena; Cotarelo, Rocio P.; Valero, M. Carmen; Cruces, Jesus</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">424</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/11223936"> <span id="translatedtitle">In vitro metabolism of aflatoxin B1 by larvae of navel orangeworm, Amyelois transitella (<span class="hlt">Walker</span>) (Insecta, Lepidoptera, Pyralidae) and codling moth, Cydia pomonella (L.) (Insecta, Lepidoptera, Tortricidae).</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Larvae of the navel orangeworm (NOW), Amyelois transitella (<span class="hlt">Walker</span>), a major pest of almonds and pistachios, and the codling moth (CM), Cydia pomonella (L.), the principal pest of walnuts and pome fruits, are commonly found in tree nut kernels that can be contaminated with aflatoxin, a potent carcinogen. The ability of larvae of these insects to metabolize aflatoxin B1 (AFB1) was examined. A field strain of NOW produced three AFB1 biotransformation products, chiefly aflatoxicol (AFL), and minor amounts of aflatoxin B2a (AFB2a) and aflatoxin M1 (AFM1). With AFL as a substrate, NOW larvae produced AFB1 and aflatoxicol M1 (AFLM1). A lab strain of CM larvae produced no detectable levels of AFB1 biotransformation products in comparison to a field strain which produced trace amounts of only AFL. Neither NOW nor CM produced AFB1-8,9-epoxide (AFBO), the principal carcinogenic metabolite of AFB1. In comparison, metabolism of AFB1 by chicken liver yielded mainly AFL, whereas mouse liver produced mostly AFM1 at a rate eightfold greater than AFL. Mouse liver also produced AFBO. The relatively high production of AFL by NOW compared to CM may reflect an adaptation to detoxify AFB1. NOW larvae frequently inhabit environments highly contaminated with fungi and, hence, aflatoxin. Only low amounts, if any, of this mycotoxin occur in the chief CM hosts, walnuts, and pome fruits. Characterizations of enzymes and co-factors involved in biotransformation of AFB1 are discussed. PMID:11223936</p> <div class="credits"> <p class="dwt_author">Lee, S E; Campbell, B C</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">425</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17504390"> <span id="translatedtitle">Cerebro-fronto-facial syndrome (Dandy-<span class="hlt">Walker</span> Variant and frontofacial dysmorphisms): report of the first case identified by increased nuchal translucency beyond 13(+6) weeks.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A 32-year-old gravida 2, para 1 woman, with a previous uneventful pregnancy, underwent first trimester ultrasound screening for Down syndrome at 13 weeks according to the Fetal Medicine Foundation guidelines (http://www.fetalmedicine.com/pdf/11-14/english/FMF-English.pdf). The ultrasound showed increased nuchal translucency (NT) of 8.9 mm with an estimated risk of Down syndrome of 1:8. Fetal karyotype was normal 46,XX by chorionic villus sampling. The patient underwent weekly ultrasound and at 19 weeks of gestation, a dilatation of the 4th ventricle with partial agenesis of the cerebellar vermis and normal posterior fossa were observed by transvaginal transcerebellar section of the fetal head. This finding was consistent with a diagnosis of Dandy-<span class="hlt">Walker</span> variant and the patient opted for termination of pregnancy after extensive counselling. Autoptic examination confirmed the prenatal ultrasonographic findings and revealed signs of an underlying cerebro-fronto-facial syndrome due to the presence of facial dysmorphisms consistent with horizontal eyelid, high nasal root, low set ears and a wide forehead. Increased NT is not only a common phenotypic expression of chromosomal abnormalities, but is also associated with a wide range of fetal defects and genetic syndromes. Careful ultrasonographic follow-up is mandatory in all cases of increased first trimester nuchal translucency with normal karyotype in order to identify associated anomalies. PMID:17504390</p> <div class="credits"> <p class="dwt_author">Tonni, Gabriele; Azzoni, Daniela; Ambrosetti, Fabrizio; de Felice, Claudio; Ventura, Alessandro</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">426</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3667004"> <span id="translatedtitle">Dandy-<span class="hlt">Walker</span> malformation and Wisconsin syndrome: novel cases add further insight into the genotype-phenotype correlations of 3q23q25 deletions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Background The Dandy-<span class="hlt">Walker</span> malformation (DWM) is one of the commonest congenital cerebellar defects, and can be associated with multiple congenital anomalies and chromosomal syndromes. The occurrence of overlapping 3q deletions including the ZIC1 and ZIC4 genes in few patients, along with data from mouse models, have implicated both genes in the pathogenesis of DWM. Methods and results Using a SNP-array approach, we recently identified three novel patients carrying heterozygous 3q deletions encompassing ZIC1 and ZIC4. Magnetic resonance imaging showed that only two had a typical DWM, while the third did not present any defect of the DWM spectrum. SNP-array analysis in further eleven children diagnosed with DWM failed to identify deletions of ZIC1-ZIC4. The clinical phenotype of the three 3q deleted patients included multiple congenital anomalies and peculiar facial appearance, related to the localization and extension of each deletion. In particular, phenotypes resulted from the variable combination of three recognizable patterns: DWM (with incomplete penetrance); blepharophimosis, ptosis, and epicanthus inversus syndrome; and Wisconsin syndrome (WS), recently mapped to 3q. Conclusions Our data indicate that the 3q deletion is a rare defect associated with DWM, and suggest that the hemizygosity of ZIC1-ZIC4 genes is neither necessary nor sufficient per se to cause this condition. Furthermore, based on a detailed comparison of clinical features and molecular data from 3q deleted patients, we propose clinical diagnostic criteria and refine the critical region for WS.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">427</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3567083"> <span id="translatedtitle">Uncaria tomentosa Exerts Extensive Anti-Neoplastic Effects against the <span class="hlt">Walker</span>-256 Tumour by Modulating Oxidative Stress and Not by Alkaloid Activity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">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 <span class="hlt">Walker</span>-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.</p> <div class="credits"> <p class="dwt_author">Dreifuss, Arturo Alejandro; Bastos-Pereira, Amanda Leite; Fabossi, Isabella Aviles; Livero, 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; Muscara, Marcelo Nicolas; Stefanello, Maria Elida Alves; Acco, Alexandra</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">428</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23408945"> <span id="translatedtitle">Uncaria tomentosa exerts extensive anti-neoplastic effects against the <span class="hlt">Walker</span>-256 tumour by modulating oxidative stress and not by alkaloid activity.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">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 <span class="hlt">Walker</span>-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</p> <div class="credits"> <p class="dwt_author">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</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-02-07</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">429</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22987394"> <span id="translatedtitle">Re-assigned diagnosis of D4ST1-deficient Ehlers-Danlos syndrome (adducted thumb-clubfoot syndrome) after initial diagnosis of Marden-<span class="hlt">Walker</span> syndrome.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We report on a 16-year-old female originally diagnosed with Marden-<span class="hlt">Walker</span> syndrome due to features such as facial dysmorphism, several musculoskeletal anomalies, and atrial septal defect in addition to hypoplasia of the inferior vermis with normal-sized cerebellum and absence of the septum pellucidum. However, an SNP array performed at age 15 years detected a total of 142?Mb of long runs of homozygosity (ROH), and put the diagnosis in doubt. Using the Genomic Oligoarray and SNP array evaluation tool (http://www.ccs.miami.edu/ROH), CHST14 provided a "hit" as a gene mapping to the largest ROH region associated with a phenotype matching our patient's (if mutated). At that time, she was a cognitively intact, thin female with growth parameters below the 3rd percentile. Craniofacial features included microcephaly, midface hypoplasia, blepharophimosis, entropion, myopia, microretrognathia, and dental malocclusion. Musculoskeletal features included kyphoscoliosis, arachnodactyly, camptodactyly, and rocker-bottom feet with interphalangeal contractures. Her skin displayed large ecchymoses and poorly healed atrophic scars. Sequencing of CHST14 revealed a complex homozygous frameshift mutation involving a 7-bp deletion and an 11-bp insertion predicted to produce a truncated protein. This mutation was not seen in 100 controls of various ethnicities. Thus, our patient represents not only a novel (homozygous) mutation in CHST14, but is also the first patient with dermatan 4-O-sulfotransferase 1-deficient Ehlers-Danlos syndrome (adducted thumb-clubfoot syndrome) (DD-EDS ATCS) documented in the Western Hemisphere. Furthermore, our patient's central nervous system anomalies have not before been described in DD-EDS (ATCS). PMID:22987394</p> <div class="credits"> <p class="dwt_author">Winters, Kevin A; Jiang, Zhijie; Xu, Weihong; Li, Shibo; Ammous, Zineb; Jayakar, Parul; Wierenga, Klaas J</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-09-14</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">430</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18482260"> <span id="translatedtitle">Population genetic structure of Chilo suppressalis (<span class="hlt">Walker</span>) (Lepidoptera: Crambidae): strong subdivision in China inferred from microsatellite markers and mtDNA gene sequences.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Chilo suppressalis (<span class="hlt">Walker</span>) displays significant geographical differences in ecological preference that may be congruent with patterns of molecular variation. To test this, we collected and analysed 381 individuals of this species from cultivated rice at 18 localities in China during the rice-growing season of 2005-2006. We used four microsatellite DNA markers and four mitochondrial DNA gene fragments. We found that this species is highly differentiated, coupled with an estimated population expansion date of at least 60 000 bp. Phylogenetic analyses, Bayesian clustering, and phylogeographical analyses of statistical parsimony haplotype network consistently divided the populations into three clades: a central China (CC) clade, a northern plus northeastern China (NN) clade and a southwestern China (SW) clade. Analysis of molecular variance indicated a high level of geographical differentiation at different hierarchical levels [F(ST) for microsatellite markers, COI, COII, 16S and ND1 is 0.06004 (P < 0.0001), 0.27607 (P < 0.0001), 0.22949 (P < 0.0001), 0.19485 (P < 0.0001) and 0.29285 (P < 0.0001), respectively]. Isolation by distance appeared among the samples from within China (r = 0.404, P = 0.0002); N(e)m values estimated using a coalescent-based method were small (< 2 migrants per generation), suggesting that the observed levels of differentiation are a result of migration-drift equilibrium. Our results imply that the genetic differentiation of this borer, which is approximately in accordance with its observed number of generations per year in different Chinese geographical regions, is probably attributed to climatic and/or geological events (e.g. the last glacial maximum) and subsequently strengthened by the domestication of rice. PMID:18482260</p> <div class="credits"> <p class="dwt_author">Meng, Xiang-Feng; Shi, Min; Chen, Xue-Xin</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-05-14</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">431</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/19523603"> <span id="translatedtitle">Enzymatic properties of alpha- and beta-glocusidases extracted from midgut and salivary glands of rice striped stem borer, Chilo suppressalis <span class="hlt">Walker</span> (Lepidoptera: Pyralidae).</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The study of digestive enzymes, especially in important pests like Chilo suppressalis <span class="hlt">Walker</span> (Lepidoptera: Pyralidae), which are a key constraint on rice production in a wide area of the globe and also in Iran, could be a successful procedure in the development of a safe and useful control strate