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1

13. SOUTHEAST TO SUCKER ROD WORK BENCH AND WOODEN SUCKER ...  

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

13. SOUTHEAST TO SUCKER ROD WORK BENCH AND WOODEN SUCKER ROD STORAGE RACKS ALONG EAST WALL OF FACTORY INTERIOR. AT THIS BENCH WORKERS RIVETED THREADED WROUGHT IRON CONNECTORS TO THE ENDS OF 20' LONG WOODEN SUCKER RODS (THE RODS WHICH EXTEND DOWNWARD IN THE WELL FROM THE GROUND SURFACE TO PISTON DISPLACEMENT PUMPS WHICH ACTUALLY ELEVATE WATER TO THE SURFACE). ROZNOR HEATER AT THE FAR RIGHT WAS ADDED CIRCA 1960. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

2

Application of fiberglass sucker rods  

SciTech Connect

Fiberglass sucker rods are assuming a place in artificial-lift technology. This paper briefly describes the manufacturing process and gives some design and operational hints for practical applications. It also describes some mathematical modeling modifications needed for fiberglass wave-equation design programs.

Gibbs, S.G. (Nabla Corporation (US))

1991-05-01

3

Fluid Dynamics in Sucker Rod Pumps  

SciTech Connect

Sucker rod pumps are installed in approximately 90% of all oil wells in the U.S. Although they have been widely used for decades, there are many issues regarding the fluid dynamics of the pump that have not been fully investigated. A project was conducted at Sandia National Laboratories to develop unimproved understanding of the fluid dynamics inside a sucker rod pump. A mathematical flow model was developed to predict pressures in any pump component or an entire pump under single-phase fluid and pumping conditions. Laboratory flow tests were conducted on instrumented individual pump components and on a complete pump to verify and refine the model. The mathematical model was then converted to a Visual Basic program to allow easy input of fluid, geometry and pump parameters and to generate output plots. Examples of issues affecting pump performance investigated with the model include the effects of viscosity, surface roughness, valve design details, plunger and valve pressure differentials, and pumping rate.

Cutler, R.P.; Mansure, A.J.

1999-01-14

4

Tests pinpoint sucker-rod failures  

SciTech Connect

A detailed metallurgical examination of a 7/8-inch and a 1-inch sucker rod revealed corrosion fatigue had caused their failure. The 7 to 8-inch rod had failed after a few months of service while the 1-inch rod failed after 1 year. Both rods had been used in a sweet-oil environment. Both rods failed by corrosion fatigue because of repeated loads during operations. Pitting because of the presence of chloride ions and carbon dioxide was initiated on the rod surface, which in turn acted as a crack origin from which the fatigue crack initiated and propagated during operations. The pitting was on the external surface. These pits were large and penetrated through the rod cross-section. Fatigue cracking is initiated at the bottom of the pit where high stress concentration is expected and propagated because the rods were subjected to the alternating stresses during operation. The extent of the fatigue crack varied in the two examined rods because of the difference in the rod heat treatment and microstructure. The paper discusses fatigue failure, the visual examination, macroscopic and microscopic examinations, rod properties, and future operations.

Elshawesh, F.; Elhoud, A.; Elagdel, E. [Petroleum Research Center, Tripoli (Libyan Arab Jamahiriya)

1997-05-26

5

Composite models for combined rod and fluid dynamics in sucker-rod pumping well systems  

SciTech Connect

This study presents the derivation and the numerical solution of composite models in which both the rod string and the fluid dynamics are coupled so as to accurately account for the effects of viscous friction in sucker-rod pumped wells. A viscous damped hyperbolic first order partial differential equation is coupled to the time derivative of Hooke's law to model the rod string motion and Navier Stokes equations are used to model the fluid dynamics in the rod-tubing annulus. A set of four equations comprise the composite model from which four sub-models for different flow scenarios are considered. The equations are solved numerically by a shock capturing algorithm known as the MacCormack Explicit Scheme which is a two-step predictor-corrector scheme and is second order accuracy in time and space. Five example problems covering various pump setting depths, fluid properties and surface pumping unit kinematics are presented to study the effects of certain important variables. From the analyses of the results of these example problems it is concluded that (1) while the effects of fluid dynamics may appear masked in shallow to medium depth sucker-rod pumped wells, they can not be ignored in deeper wells where large discrepancies occur in the prediction of system parameters, (2) the load range decreases moderately as viscosity increases and the predicted polished rod horsepower does not change significantly over the range of viscosities studied in shallow to medium depth sucker-rod pumped wells, (3) the presence of small quantities of the gas phase in the fluid column reduces system peak torque and precipitate the need for smaller counterbalance weights and (4) the influence of two-phase gas-liquid flow in the rod-tubing annulus on system design parameters declines with increasing pump setting depth. The results are compared against other design models appearing in the literature.

Lekia, S.D.L.

1989-01-01

6

Radial pressure sensor of sucker rod based on LabVIEW  

NASA Astrophysics Data System (ADS)

The eccentric wear, fracture and other phenomena often occur to the sucker rod in major oil fields. It turns out that the radial pressure of sucker rod suffered is the main reason for its eccentric wear. It is necessary to analyze the eccentric wear and fracture of sucker rod in the pumping process. It is also important to measure the radial pressure for the downhole sucker rod accurately. The radial pressure could be analyzed when sucker rod is extruded, collided or sustained friction based on the material mechanics and the fluid dynamics. The mechanical structure is designed for measuring the radial pressure. The data processing system for radial pressure of down-hole sucker rod based on LabVIEW is developed in this paper. The functions are real-time data acquisition and processing for sucker rod radial pressure. The communication of LabVIEW and Access database had been realized. The database management system for radial pressure of sucker rod is built, which could be used to achieve the data storage, historical data retrieval analysis, data organization and calculation. The computer simulation is carried out to verify the reasonability of the theoretical analysis and structure design.

Wang, Zhongyu; Yan, Hu; Li, Qiang

2013-10-01

7

An investigation of analytical and numerical sucker rod pumping mathematical models  

E-print Network

AN INVESTIGATION OF ANALYTICAL AND NUMERICAL SUCKER ROD PUMPING MATHEMATICAL MODELS A Thesis by DONALD JOSEPH SCHAFER Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1987 Major Subject: Petroleum Engineering AN INVESTIGATION OF ANALYTICAL AND NUMERICAL SUCKER ROD PUMPING MATHEMATICAL MODELS A Thesis by DONALD JOSEPH SCHAFER Approved as to style and content by: 7d JW. J ni (Chai...

Schafer, Donald Joseph

2012-06-07

8

Finite element analysis of sucker rod couplings with guidelines for improving fatigue life  

SciTech Connect

The response of a variety of sucker rod couplings to an applied axial load was simulated using axisymmetric finite element models. The calculations investigated three sucker rod sizes and various combinations of the slimhole, Spiralock, and Flexbar modifications to the coupling. In addition, the effect of various make-ups (assembly tightness) on the performance of coupling was investigated. An axial load was applied to the sucker rod ranging from {minus}5 ksi to 40 ksi, encompassing three load cycles identified on a modified Goodman diagram as acceptable for indefinite service life of the sucker rods. The simulations of the various coupling geometries and make-ups were evaluated with respect to how well they accomplish the two primary objectives of preloading threaded couplings: (1) to lock the threaded coupling together so that it will not loosen and eventually uncouple, and (2) to improve the fatigue resistance of the threaded connection by reducing the stress amplitude in the coupling when subjected to cyclic loading. Perhaps the most significant finding in this study was the characterization of the coupling parameters which affect two stress measures. The mean hydrostatic stress, which determines the permissible effective alternating stress, is a function of the coupling make-up. Whereas, the alternating effective stress is a function of the relative stiffnesses of the pin and box sections of the coupling and, as long as the coupling does not separate, is unaffected by the amount of circumferential displacement applied during make-up. The results of this study suggest approaches for improving the fatigue resistance of sucker rod couplings.

Hoffman, E.L. [Sandia National Labs., Albuquerque, NM (United States). Engineering and Structural Mechanics Div.

1997-09-01

9

Sucker rod pumping unit diagnostics using an expert system: and pattern recognition technique  

E-print Network

, The objective of this study is to apply expert system technology in the diagnostics of sucker rod pumping units. This approach helps to capture expert' s knowledge , often held by a few individuals, and make it available in the field wherever a personal... computer is available. The captured knowledge becomes permanently recorded and can be updated as the system solves more difficult problems. A rule-based expert system has been developed to help the user analyze the subsurface pump problems. Based...

Derek, Henryk Jozef

2012-06-07

10

Fiberglass rods present a new economic model to marginal well producers  

SciTech Connect

Fiberglass sucker rods are not new. They`ve been around for over a decade, and much has been done to improve upon their basic promise of high strength-to-weight ratio, corrosion resistance, and ease of handling. Likely the main, if not the only, reason they have not assumed prominence in the market is a resistance to change, particularly when a well becomes marginal. Operators feel that changing out their rod string is like betting on a tired horse. But there are several different scenarios involving fiberglass rods that make economic sense. To understand the argument for fiberglass rods, a case by case analysis is presented.

Ghiselin, D.

1996-08-01

11

Study on the anti-wear performance of Ni-base composite coating sucker joint that contains nano-diamond and nano-polytetrafluoroethylene.  

PubMed

With the development of oilfields, the problem of eccentric wear between casing and sucker rod in rod-pumped wells operation is more and more severe. Investigations on the eccentric wear show that the abrasion of sucker rod joint is more serious than the sucker rod itself. A new method of producing the Ni-base composite coating that contains nano-diamond and nano-polytetrafluoroethylene (PTFE) on sucker joint obtained by electrodeposition is presented in this paper. The test results show that the anti-wear performance and hardness of the sucker rod improve significantly with the increase of nano-diamond. The addition of nano-PTFE particle is useful in reducing the friction factor. Field tests demonstrate that the life of the sucker rod joint is increased and the maintenance cycle of the rod-pumped well is prolonged. PMID:19441509

Wang, Wei-Zhang; Yan, Xiang-Zhen; Wang, Hai-Wen; Wang, Ming-Bo

2009-02-01

12

Reproduction of three species of suckers (Catostomidae) in British Columbia.  

E-print Network

??Reproduction of three species of suckers, Catostomus catostomus, the longnose sucker, Catostomus commersoni, the white sucker, and Catostomus macrocheilus, the largescale sucker, has been studied… (more)

Geen, Glen Howard

2012-01-01

13

Environmental stimuli promoting sucker initiation in sugarcane  

Microsoft Academic Search

The presence of suckers, late-formed tillers, in mature sugarcane crops reduces the sugar concentration of harvested material to the detriment of profitability. The amount of suckering varies with cultivar and season. However, the environmental stimuli promoting suckering, i.e. the number of suckers, are not understood. This paper describes the effects on suckering of increasing soil moisture, nitrogen, and the level

G. D. Bonnett; B. Salter; N. Berding; A. P. Hurney

2005-01-01

14

Trichodina Sucker Disk  

Microsoft Academic Search

\\u000a Trichodinids are characterized by a sucker-like disk that enables them to adhere to host surfaces. The disk is reinforced\\u000a by a band of radially arranged ribs or striae which are attached to a narrow pellicular band about the periphery. The skeletal\\u000a or denticulate ring is 44–62??m in outside diameter, 29–46??m in ring diameter, and lies immediately posterior to the striae

Hermann Ehrlich

15

“Never Give a Sucker an Even Break”  

Microsoft Academic Search

Suckers are thought to be harmful to other species of fish because of predation on eggs and fry and from competition, mainly for food. This belief has led to many sucker removal projects to enhance sport fisheries. In a review of the literature, we found that (1) although suckers eat eggs and fry of some fishes, there was no evidence

Mark Holey; Bruce Hollender; Mark Imhof; Roman Jesien; Richard Konopacky; Michael Toneys; Daniel Coble

1979-01-01

16

Fluid inertia consideration in sucker rod pump diagnosis  

E-print Network

conditions. However, existing state-of-the-art diagnostic models neglect fluid-inertia forces. In shallow wells with large lifting rates, dynamic fluid forces can be significant and result in poor diagnostic model performance. This research is motivated...

Csaszar, Albert Bela

2012-06-07

17

A Dynamic Investigation of Sucker-Rod Pumping  

E-print Network

FORTRAN LISTING OF SIMULATOR PROGRAM 3 3 :Vvv4M!C A N A L Y S I S nf" S U C K E R R O D P U M P I N G S Y S T M E R M K •> v C'•* N"' (." Z ) = A T A N ( 7.7 t i P O R T M • « 71*17.) ) ) \\ ' C S R ( Z ) S AT AM ( R 0 R T ( 1 . - 7.7 * 77)7 71) P... ) + R S T H 1 5 1 I F ( T H T A + 9,4 2 4 8 7 8 - B T RT A ) 9 6 , 3 § 9 , 3 9.9. 13>2 3 9 9 P U N C H S, TI U N E V U ) I P R L _ 1 5.3. ?L.F. C'RM AXT.3.EL.6.XJLJ . — 1 P 4 N P S = N=>S + 1 1-55 I F < K 0 U M T - 5 ) 9 6 , 9 4 , 9 4 ... 15FT 94 A...

Knapp, Roy M.

1969-01-01

18

Rangewide molecular structuring in the Utah sucker ( Catostomus ardens )  

Microsoft Academic Search

The Utah sucker ( Catostomus ardens ) is endemic to the Bonneville Basin and the upper Snake River drainage in western North America, and is thought to hybridize with the federally endangered June sucker ( Chasmistes liorus mictus ) in Utah Lake (Bonneville Basin). Here we describe the discovery of a major subdivision in Utah suckers (4.5% mitochondrial sequence divergence)

K. E. M OCK; R. P. E VANS; M. CRAWFORD; B. L. C ARDALL; S. U. J ANECKE; M. P. MILLER

2006-01-01

19

Predation on lake whitefish eggs by longnose suckers  

USGS Publications Warehouse

In November 1981, we observed intense predation on lake whitefish (Coregonus clupeaformis) eggs by longnose suckers (Catostomus catostomus) on lake whitefish spawning grounds in northwestern Lake Huron. Since longnose suckers commonly frequent the same habitat used by spawning lake whitefish, there exists the potential for high losses of eggs due to sucker predation.

Nester, Robert T.; Poe, Thomas P.

1984-01-01

20

Distribution and Habitat Associations of Radio-Tagged Adult Lost River Suckers and Shortnose Suckers in Upper Klamath Lake, Oregon  

Microsoft Academic Search

Radiotelemetry was used to investigate the summer distribution and diel habitat associations of endangered adult Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris in northern Upper Klamath Lake, Oregon. From 2002 to 2004, Lost River and shortnose suckers were tracked by boat, and water depth and water quality were measured at each fish location. A series of water

Nolan P. Banish; Barbara J. Adams; Rip S. Shively; Michael M. Mazur; David A. Beauchamp; Tamara M. Wood

2009-01-01

21

Demographic analysis of Lost River sucker and shortnose sucker populations in Upper Klamath Lake, Oregon  

USGS Publications Warehouse

We used 13 years (1995-2007) of capture-mark-recapture data to assess population dynamics of endangered Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris in Upper Klamath Lake, Oregon. The Cormack-Jolly-Seber method was used to estimate survival, and information theoretic modeling was used to assess variation due to time, gender, species, and spawning subpopulations. Length data were used to detect multiple year-class failures and events of high recruitment into adult spawning populations. Average annual survival probability was 0.88 for Lost River suckers and 0.76 for shortnose suckers. Mean life span estimates based on these survival rates indicated that Lost River suckers survived long enough on average to attempt reproduction eight times, whereas shortnose suckers only survived to spawn three to four times. Shortnose sucker survival was not only poor in years of fish kills (1995-1997) but also was low in years without fish kills (i.e., 2002 and 2004). This suggests that high mortality occurs in some years but is not necessarily associated with fish kills. Annual survival probabilities were not only different between the two species but also differed between two spawning subpopulations of Lost River suckers. Length composition data indicated that recruitment into spawning populations only occurred intermittently. Populations of both species transitioned from primarily old individuals with little size diversity and consistently poor recruitment in the late 1980s and early 1990s to mostly small, recruit-sized fish by the late 1990s. A better understanding of the factors influencing adult survival and recruitment into spawning populations is needed. Monitoring these vital parameters will provide a quantitative means to evaluate population status and assess the effectiveness of conservation and recovery efforts.

Janney, E. C.; Shively, R. S.; Hayes, B. S.; Barry, P. M.; Perkins, D.

2008-01-01

22

The Phylogeography of the Mountain Sucker [Catostomus (Pantosteus) platyrhynchus].  

E-print Network

??Pantosteus, a subgenus of Catostomus, includes the mountain sucker (Catostomus playthyrnchus), whose speculated older origins in the Miocene/Pliocene can provide insight into the ancient geographical… (more)

Laitnen, Nina Johanna

2012-01-01

23

Physiological stress response of Mountain Whitefish (Prosopium williamsoni) and White Sucker (Catostomus  

E-print Network

Physiological stress response of Mountain Whitefish (Prosopium williamsoni) and White Sucker of the Mountain Whitefish, (Prosopium williamsoni, a cold-water fish) and White Sucker (Catostomus commersoni

Hontela, Alice

24

Ecomorphological and Genetic Investigations into the Utah Lake, UT Sucker Complex with Comparisons to the Jackson Lake, WY Sucker Complex.  

E-print Network

??Ecomorphological specialization within Catostomidae in several large western North American lakes has produced populations including typical benthic suckers (Catostomus) and lakesuckers (Chasmistes), mid-water planktivores, with… (more)

Cole, David

2014-01-01

25

Life History of the Mountain Sucker, Catostomus platyrhynchus, in Montana  

Microsoft Academic Search

The life history of the mountain sucker, Catostomus platyrhynchus, was studied in southwestern Montana during 1966 and 1967. Most specimens studied were collected from two streams by seining or electrofishing. Annuli were determined on scales from 491 fish. Annuli were formed during early June. Growth history of mountain suckers was based on the calculated length at the last annulus for

William J. Hauser

1969-01-01

26

FACTORS INFLUENCING GROWTH AND SURVIVAL OF WHITE SUCKER, CATOSTOMUS COMMERSONI  

EPA Science Inventory

Growth responses of the white sucker, Catostomus commersoni, were examined in relation to the influence of temperature, body size, season, daylength, light intensity, food ration level and food quality. Sucker growth was maximum at a temperature range of 19-26C, depending upon ex...

27

Selective ingestion of detritus by a north temperate omnivorous fish, the juvenile white sucker, Catostomus commersoni  

Microsoft Academic Search

The capacity of the juvenile white sucker, Catostomus commersoni, to feed selectively on detritus was examined by analyzing gut contents of fish feeding in a northern Michigan pond and in laboratory aquaria. Suckers selected fine particle detritus. The median length of detritus particles consumed by pond suckers ranged from 26–38 µm for all seasons sampled. Although suckers in the pond

Molly O. Ahlgren

1996-01-01

28

Evaluation of Thermal Requirements for the Propagation and Recovery of June Suckers  

Microsoft Academic Search

Determining the optimal rearing temperature for the June sucker Chasmistes liorus has been identified as a key component necessary for the design of a new June sucker hatchery and for achieving the June Sucker Recovery Implementation Program supplementation goal of 350,000 fish of 20-cm length annually. A laboratory study was conducted to monitor the performance of June suckers reared at

Greg A. Kindschi; Matt Toner; William C. Fraser; M. Doug Routledge; Maureen Wilson; Yvette Converse

2008-01-01

29

Virtual strings  

Microsoft Academic Search

A virtual string is a scheme of self-intersections of a closed curve on a surface. We introduce virtual strings and study their geometric properties and homotopy invariants. We also discuss connections between virtual strings, Gauss words, and virtual knots.

Vladimir Turaev

2003-01-01

30

Hairy suckers: the surface microstructure and its possible functional significance in the Octopus vulgaris sucker  

PubMed Central

Summary Octopus suckers are able to attach to any smooth surface and many rough surfaces. Here, we have discovered that the sucker surface, which has been hypothesised to be responsible for sealing the orifice during adhesion, is not smooth as previously assumed, but is completely covered by a dense network of hair-like micro-outgrowths. This finding is particularly important because it provides another demonstration of the role of hair-structures in a sealing mechanism in water, similar to that previously described for clingfish and abalones. Moreover, the discovered hairs may provide an additional adhesive mechanism that works in concert with suction. The discovered surface structures might be potentially interesting for biomimetics of novel technical suction cups with improved adhesion capabilities on non-smooth surfaces. PMID:24991492

Appel, Esther

2014-01-01

31

Cinderella Strings  

E-print Network

We investigate recent claims concerning a new class of cosmic string solutions in the Weinberg-Salam model. They have the general form of previously discussed semi-local and electroweak strings, but are modified by the presence of a non-zero W-condensate in the core of the string. We explicitly construct such solutions for arbitrary values of the winding number $N$. We then prove that they are gauge equivalent to bare electroweak strings with winding number $N-1$. We also develop new asymptotic expressions for large-$N$ strings.

A. Achucarro; R. Gregory; J. A. Harvey; K. Kuijken

1993-12-03

32

Cinderella Strings  

E-print Network

We investigate recent claims concerning a new class of cosmic string solutions in the Weinberg-Salam model. They have the general form of previously discussed semi-local and electroweak strings, but are modified by the presence of a non-zero W-condensate in the core of the string. We explicitly construct such solutions for arbitrary values of the winding number $N$. We then prove that they are gauge equivalent to bare electroweak strings with winding number $N-1$. We also develop new asymptotic expressions for large-$N$ strings.

Achúcarro, A; Harvey, J A; Kuijken, K

1994-01-01

33

Root suckering patterns in Populus euphratica (Euphrates poplar, Salicaceae)  

Microsoft Academic Search

To understand the spatial structure of monospecific Tugai forests (Xinjiang Province, China) growing as gallery woods nourished\\u000a by ground water, root suckering in Populus euphratica was studied by a combination of morphological and molecular analyses. Seedlings grow a deep tap root and keep this as adult\\u000a trees, whereas root suckers never develop a tap root but utilize the horizontally stretching

Martin Wiehle; Pascal Eusemann; Niels Thevs; Martin Schnittler

2009-01-01

34

Structure and mechanical properties of Octopus vulgaris suckers  

PubMed Central

In this study, we investigate the morphology and mechanical features of Octopus vulgaris suckers, which may serve as a model for the creation of a new generation of attachment devices. Octopus suckers attach to a wide range of substrates in wet conditions, including rough surfaces. This amazing feature is made possible by the sucker's tissues, which are pliable to the substrate profile. Previous studies have described a peculiar internal structure that plays a fundamental role in the attachment and detachment processes of the sucker. In this work, we present a mechanical characterization of the tissues involved in the attachment process, which was performed using microindentation tests. We evaluated the elasticity modulus and viscoelastic parameters of the natural tissues (E ? 10 kPa) and measured the mechanical properties of some artificial materials that have previously been used in soft robotics. Such a comparison of biological prototypes and artificial material that mimics octopus-sucker tissue is crucial for the design of innovative artificial suction cups for use in wet environments. We conclude that the properties of the common elastomers that are generally used in soft robotics are quite dissimilar to the properties of biological suckers. PMID:24284894

Tramacere, Francesca; Kovalev, Alexander; Kleinteich, Thomas; Gorb, Stanislav N.; Mazzolai, Barbara

2014-01-01

35

Rod Ratios  

NSDL National Science Digital Library

This activity builds student knowledge of ratios by using Cuisenaire rods to determine proportion and form equivalent ratios. Students may use the Cuisenaire rod environment embedded in this resource or they may use actual Cuisenaire rods depending on preference/ability/accessibility. This resource includes teacher notes, solution, and suggestions for questioning.

Team, Nrich

2013-01-01

36

Bowed Strings  

NASA Astrophysics Data System (ADS)

In the next eight chapters, we consider some aspects of the science of bowed string instruments, old and new. In this chapter, we present a brief discussion of bowed strings, a subject that will be developed much more thoroughly in Chap. 16. Chapters 13-15 discuss the violin, the cello, and the double bass. Chapter 17 discusses viols and other historic string instruments, and Chap. 18 discusses the Hutchins-Schelleng violin octet.

Rossing, Thomas D.; Hanson, Roger J.

37

Waving Strings  

NSDL National Science Digital Library

Unless you really haven't been paying attention to the world around you, you know that plucked strings produce sounds. Carlos Santana demonstrates this on a regular basis. Because stringed instruments are so commonly used to produce sounds, we're going to spend a chapter figuring out what exactly those strings are doing when you pluck them. We're going to be analyzing what happens when you produce waves on strings. These waves produce sounds, but they are not themselves sound waves.

Robertson, William C.

2003-01-01

38

String Thing  

NSDL National Science Digital Library

String Thing is an interactive online game in which learners change a virtual string's tension, length, and gauge to create different musical pitches. Educators can use this game as an introduction to sound and before completing any activities on music or building instruments. Alternatively, educators can use this game to review or assess these concepts.

Wgbh

2010-01-01

39

South Carolina Pest Management Handbook for Field Crops -2013 TOBACCO SUCKER CONTROL  

E-print Network

markets. Growers are using new sucker control programs that offer excellent late-season sucker control of other pesticides and surfactants with fatty alcohols is prohibited. Antak EC Royaltac EC Fairtac EC n

Stuart, Steven J.

40

Vanishing Rods  

NSDL National Science Digital Library

This is a quick activity/demonstration that introduces learners to the concept of index of refraction. Learners place stirring rods in a jar of water and notice they can see them clearly. They will be surprised when they place the stirring rods in a jar of vegetable oil and the rods appear practically invisible! This is a dramatic demonstration that effectively illustrates how light can bend and fool the eye.

University, Colorado S.

2009-01-01

41

Hazard assessment of selenium to endangered razorback suckers (Xyrauchen texanus)  

USGS Publications Warehouse

A hazard assessment was conducted based on information derived from two reproduction studies conducted with endangered razorback suckers (Xyrauchen texanus) at three sites near Grand Junction, CO, USA. Selenium contamination of the upper and lower Colorado River basin has been documented in water, sediment, and biota in studies by US Department of the Interior agencies and academia. Concern has been raised that this selenium contamination may be adversely affecting endangered fish in the upper Colorado River basin. The reproduction studies with razorback suckers revealed that adults readily accumulated selenium in various tissues including eggs, and that 4.6 ??g/g of selenium in food organisms caused increased mortality of larvae. The selenium hazard assessment protocol resulted in a moderate hazard at the Horsethief site and high hazards at the Adobe Creek and North Pond sites. The selenium hazard assessment was considered conservative because an on-site toxicity test with razorback sucker larvae using 4.6 ??g/g selenium in zooplankton caused nearly complete mortality, in spite of the moderate hazard at Horsethief. Using the margin of uncertainty ratio also suggested a high hazard for effects on razorback suckers from selenium exposure. Both assessment approaches suggested that selenium in the upper Colorado River basin adversely affects the reproductive success of razorback suckers. ?? 2002 Elsevier Science B.V. All rights reserved.

Hamilton, S.J.; Holley, K.M.; Buhl, K.J.

2002-01-01

42

Age, Growth, and Reproduction of Mountain Suckers in Lost Creek Reservoir, Utah  

Microsoft Academic Search

In this paper, we summarize aspects of the life history of mountain suckers Catostomus platyrhynchus in Lost Creek Reservoir, Utah, and compare our findings with populations in two Montana streams as reported in the only detailed life history paper on the mountain sucker previously published. Mountain suckers in Lost Creek Reservoir, Utah, grew faster than did populations in Flathead Creek

Richard G. Wydoski; Richard S. Wydoski

2002-01-01

43

Patterns of Intra-and Interspecies Genetic Diversity in Klamath River Basin Suckers  

E-print Network

Patterns of Intra- and Interspecies Genetic Diversity in Klamath River Basin Suckers GREGORY J Abstract.--The Klamath River basin, Oregon, is home to four catostomid species: the Klamath smallscale variation in Klamath River basin suckers by examining 15 microsatellite loci. Over 300 suckers were sampled

May, Bernie

44

Observations of Age-O Blue Sucker, Cycleptus elongatus Utilizing an Upper Missouri River Backwater  

E-print Network

-NOTE- Observations of Age-O Blue Sucker, Cycleptus elongatus Utilizing an Upper Missouri River Backwater ABSTRACT The early life history of blue sucker (Cyc/eptus elongatus) is relatively unknown across corridors, the status ofblue sucker (Cyc/eptus elongatus) popUlations has become questionable. Several

45

Cosmic strings  

NASA Technical Reports Server (NTRS)

Cosmic strings are linear topological defects which are predicted by some grand unified theories to form during a spontaneous symmetry breaking phase transition in the early universe. They are the basis for the only theories of galaxy formation aside from quantum fluctuations from inflation based on fundamental physics. In contrast to inflation, they can also be observed directly through gravitational lensing and their characterisitc microwave background anisotropy. It was recently discovered that details of cosmic string evolution are very differnt from the so-called standard model that was assumed in most of the string-induced galaxy formation calculations. Therefore, the details of galaxy formation in the cosmic string models are currently very uncertain.

Bennett, David P.

1988-01-01

46

String Phenomenology  

E-print Network

Following Dyson's analogy between the quantum field theory and the 19th-century chemistry-both explain how but not why-one could also establish an analogy between atomic physics and string theory. Atomic physics was needed to answer the question why in chemistry, string theory is trying to answer the question why in the standard model. This attempt is very briefly reviewed in this talk. After discussing the phenomenological aspects of string theory, the study of soft terms is emphasized as a possible connection between theory and experiment. Special attention is paid to the issues of flavor changing neutral currents, loop effects, charge and color breaking minima, and M-theory versus weakly coupled string theory.

C. Muñoz

1998-02-23

47

Rodding Surgery  

MedlinePLUS

... may be rodded to reduce a scoliosis. With modern anesthesia, children can undergo surgery for longer periods ... recovery. Your doctor or physical therapist can suggest techniques for reducing their pain and frequency. For more ...

48

Observations on the Longnose Sucker in Yellowstone Lake  

Microsoft Academic Search

An investigation was made of the food, spawning runs, age and growth, and distribution of the longnose sucker Catostomus catostomus in Yellowstone Lake during the summers of 1951 and 1952. This fish was probably accidentally introduced into Yellowstone Lake by bait fishermen in the early thirties. As many as 2,000 specimens were observed with the annual cutthroat-trout runs in Pelican

C. J. D. Brown; Richard J. Graham

1954-01-01

49

A Proposed Standard Weight Equation for Blue Suckers  

Microsoft Academic Search

Length and weight data were obtained from 46 populations of blue suckers Cycleptus elongatus (N = 8,811 fish) across the species' geographic distribution to develop a standard weight (Ws) equation. The Ws equation was derived using the empirical percentile technique applied to fish between 240 and 809 mm total length (TL). We calculated a quadratic model and a linear model

Ben C. Neely; Martin J. Hamel; Kirk D. Steffensen

2008-01-01

50

Small nonnative fishes as predators of larval razorback suckers  

USGS Publications Warehouse

The razorback sucker (Xyrauchen texanus), an endangered big-river fish of the Colorado River basin, has demonstrated no sustainable recruitment in 4 decades, despite presence of spawning adults and larvae. Lack of adequate recruitment has been attributed to several factors, including predation by nonnative fishes. Substantial funding and effort has been expended on mechanically removing nonnative game fishes, typically targeting large predators. As a result, abundance of larger predators has declined, but the abundance of small nonnative fishes has increased in some areas. We conducted laboratory experiments to determine if small nonnative fishes would consume larval razorback suckers. We tested adults of three small species (threadfin shad, Dorosoma petenense; red shiner, Cyprinella lutrensis; fathead minnow, Pimephales promelas) and juveniles of six larger species (common carp, Cyprinus carpio; yellow bullhead, Ameiurus natalis; channel catfish, Ictalurus punctatus; rainbow trout, Oncorhynchus mykiss; green sunfish, Lepomis cyanellus; bluegill, L. macrochirus). These nonnative fishes span a broad ecological range and are abundant within the historical range of the razorback sucker. All nine species fed on larval razorback suckers (total length, 9-16 mm). Our results suggest that predation by small nonnative fishes could be responsible for limiting recovery of this endangered species.

Carpenter, J.; Mueller, G.A.

2008-01-01

51

Cosmic Strings and Superconducting Cosmic Strings.  

National Technical Information Service (NTIS)

The possible consequences of forming cosmic strings and superconducting cosmic strings in the early universe are discussed. Lecture 1 describes the group theoretic reasons for, and the field theoretic reasons why, cosmic strings can form in spontaneously ...

E. Copeland

1988-01-01

52

Cosmic strings and superconducting cosmic strings  

NASA Technical Reports Server (NTRS)

The possible consequences of forming cosmic strings and superconducting cosmic strings in the early universe are discussed. Lecture 1 describes the group theoretic reasons for and the field theoretic reasons why cosmic strings can form in spontaneously broken gauge theories. Lecture 2 discusses the accretion of matter onto string loops, emphasizing the scenario with a cold dark matter dominated universe. In lecture 3 superconducting cosmic strings are discussed, as is a mechanism which leads to the formation of structure from such strings.

Copeland, Edmund

1988-01-01

53

Hairy strings  

SciTech Connect

Zero modes of the world-sheet spinors of a closed string can source higher order moments of the bulk supergravity fields. In this work, we analyze various configurations of closed strings focusing on the imprints of the quantized spinor vacuum expectation values onto the tails of bulk fields. We identify supersymmetric arrangements for which all multipole charges vanish; while for others, we find that one is left with Neveu-Schwarz-Neveu-Schwarz, and Ramond-Ramond dipole and quadrupole moments. Our analysis is exhaustive with respect to all the bosonic fields of the bulk and to all higher order moments. We comment on the relevance of these results to entropy computations of hairy black holes of a single charge or more, and to open/closed string duality.

Sahakian, Vatche [Keck Laboratory, Harvey Mudd College, Claremont, California 91711 (United States)

2006-01-15

54

Plucked Strings  

NASA Astrophysics Data System (ADS)

In the next ten chapters we will discuss the science of plucked string instruments. Acoustic guitars and lutes are discussed in Chap. 3. Portuguese guitars, used in fado music, are discussed in Chap. 4 and guitars in Chap. 5, while electric guitars are discussed in Chap. 22. Banjos are discussed in Chap. 5, while mandolins are the subject of Chap. 6. Zithers and psalteries, especially Baltic psalteries, are discussed in Chap. 7. Harpsichords are discussed in Chap. 8, while harps are discussed in Chap. 9 and 10. Finally, plucked string instruments from Asia, such as the kito, shamisen, biwa, gayageum, geomungo, ch'in, p'I-p'a, and sitar are discussed in Chap. 11. These instruments are very different in character and in their musical roles, but they all depend upon plucked strings vibrating and exciting one or more soundboards or radiating surfaces.

Rossing, Thomas D.

55

String Theory  

NSDL National Science Digital Library

While few people toss around terms like Astroparticle Physics and Superstring Theory, we've all found ourselves staring out in to space on a starry night wondering what's out there, why it's arranged the way it is, and where it all came from. For some, it simply comes down to strings. This September 2, 2003 New York Times article does a good job of summarizing the history and specifics of string theory and the paradox of its many offerings (1). One-time egistration is required to access any New York Times articles. The next site is the homepage of the Kavli Institute for Theoretical Physics at the University of California Santa Barbara and home to some of the most intense thinking with regards to theoretical physics in the world (2). Going from highly technical to more popularly palatable, NOVA offers the third site (3 ). Called, The Elegant Universe, the upcoming NOVA special is based on Columbia University professor Brian Greene's highly acclaimed book of the same title. As the site states, "Eleven dimensions, parallel universes, and a world made out of strings. It's not science fiction, it's string theory." The next site takes you directly to the virtual home of string theory (4 ). Here you will find the basics on the topic as well as what scientists have found so far and where they're headed next. Probably the most definitive site devoted to the topic. The fifth site is another informative look at superstring theory and is provided by John Pierre at MIT. While a very basic Web site, in terms of design, it offers a great tutorial on strings in addition to a glossary and reference list (5 ). The final link (6 ) will take you "Beyond Einstein, from the Big Bang to Black Holes." The site, provided by NASA, offers insights into the history and structure of the universe.

Morgan, John P.

56

No Genetic Evidence for Hybridization Between Rio Grande Sucker, Catostomus Plebeius , and the Introduced White Sucker, Catostomus Commersoni , in the Rio Grande  

Microsoft Academic Search

Hybridization with the introduced white sucker, Catostomus commerson, has been blamed in part for the decline of the Rio Grande sucker, C. plebeius, in the upper Rio Grande basin of Colorado and New Mexico but without convincing evidence. Here we report results from a genetic study of hybridization between the two species across their sympatric range in New Mexico. We

Megan V. McPhee; Thomas F. Turner

2004-01-01

57

String Cells  

NSDL National Science Digital Library

The String Cell project involves the construction of a cell model, companion poster, and a travel brochure. The cell and companion poster must accurately represent the organelles of the cell for structure and function. The brochure is designed to entice a sub-cellular visitor to visit their "cellular resort".

BEGIN:VCARD VERSION:2.1 FN:Marlys McCurdy N:McCurdy;Marlys ORG:Idaho State University/ College of Education REV:2005-04-12 END:VCARD

1995-06-30

58

String cosmologies  

Microsoft Academic Search

A model of a cloud formed by massive strings is studied in the context of the usual general relativity. This model is used as a source of Bianchi type I and ''Kantowski-Sachs'' type of cosmological models. Some global properties of the above-mentioned cosmological models are studied for the equation of state (energy density) proportional (tension density). Particular models that can

Patricio Letelier

1983-01-01

59

String Theory  

Microsoft Academic Search

For each $n > 0$, two alternative axiomatizations of the theory of strings over $n$ alphabetic characters are presented. One class of axiomatizations derives from Tarski's system of the Wahrheitsbegriff and uses the $n$ characters and concatenation as primitives. The other class involves using $n$ character-prefixing operators as primitives and derives from Hermes' Semiotik. All underlying logics are second order.

John Corcoran; William Frank; Michael Maloney

1974-01-01

60

Teaching Strings.  

ERIC Educational Resources Information Center

Intended primarily for use by instrumental music teachers who do not have a major concentration in strings, this guide provides pertinent basic resources, materials, teaching--learning expectation, and a general overall guide to achievement levels at various stages of development. Discussions are presented of Choosing the Proper Method Book,…

New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

61

Mountain Sucker (Catostomus platyrhynchus): A Technical Conservation Assessment  

Microsoft Academic Search

ACKNOWLEDGMENTS We thank the many biologists and managers from Colorado, Nebraska, South Dakota, and Wyoming and from the national forests within Region 2 who provided information about mountain sucker populations, status, and management,in their jurisdictions. We also extend our appreciation to David B. McDonald at the University of Wyoming,for the population demographic,matrix analysis he provided. We especially thank Richard Vacirca

Laura Thel Belica; Nathan P. Nibbelink

62

Biological Notes on Blue Suckers in the Mississippi River  

Microsoft Academic Search

The total length (L, mm)-weight (W, g) relationship for 153 blue suckers (Cycleptus elongatus) collected from areas of swift current in Pool 20, Mississippi River, was log10W = ?6.69 + 3.59(log10L). Condition factors (K = 10W\\/L) were 0.74?1.1; they increased with increasing fish size, and varied among months (March-October) and between years (1977–1978). Fin rays had more discernible annuli than

Randall J. Rupprecht; Lawrence A. Jahn

1980-01-01

63

String mediated phase transitions  

NASA Technical Reports Server (NTRS)

It is demonstrated from first principles how the existence of string-like structures can cause a system to undergo a phase transition. In particular, the role of topologically stable cosmic string in the restoration of spontaneously broken symmetries is emphasized. How the thermodynamic properties of strings alter when stiffness and nearest neighbor string-string interactions are included is discussed.

Copeland, ED; Haws, D.; Rivers, R.; Holbraad, S.

1988-01-01

64

The "Magic" String  

ERIC Educational Resources Information Center

The "Magic" String is a discrepant event that includes a canister with what appears to be the end of two strings protruding from opposite sides of it. Due to the way the strings are attached inside the canister, it appears as if the strings can magically switch the way they are connected. When one string end is pulled, the observer's expectation…

Hoover, Todd F.

2010-01-01

65

A heirarchy of pattern recognition algorithms for the diagnosis of sucker rod pumped wells  

E-print Network

unanchored tubing or tubing anchor not holding 9 Leaking traveling valve or plunger 12 13 10 Severe standing valve leak 13 11 Leaking valves 15 12 Gas interference 15 13 Gas lock 14 Fluid pound 15 17 15 Worn or split barrel 16 Parted tubing 17... or plunger leak 58 Severe traveling valve leak 59 Leaking traveling valve or plunger 85 60 Severe standing valve leak LIST OF FIGURES (CONTINUED) FIGURE 61 Combination of leaking SV and TV and gas interference Page 85 62 Pump hitting down (spaced too...

Houang, Anne-Benedicte

2012-06-07

66

An improved finite difference calculation of downhole dynamometer cards for sucker rod pumps  

E-print Network

. Donald J. Schafer for his help in the early stages of this work. To Jo Ann, whose love and gracious support made this thesis possible. TABLE OF CONTENTS Page ABSTRACT ACKNOWLEDGMENTS TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES INTRODUCTION.... D. J. Schafer programmed both of these models and studied the required input parameters for each. Schafer's predictive program only simulated pumping systems under the ideal conditions of complete pump fillage. J. V. Jennings later improved...

Everitt, Thomas Aaron

2012-06-07

67

Development of a new model for predicting sucker-rod pumping system performance  

E-print Network

-tubing frictional losses. Schafer compared actual dynamometer cards to the cards generated by a predictive model and concluded that the coefficient c ranges from 0. 5 to 1. 2 sec " in actual pumping operations. Boundary and Initial Conditions Imposed... in Eqs. 15 and 16 to calculate the displacement and velocity vectors. 30 VERIFICATION OF MODEL ACCURACY Verification of Proposed Model to Established Models To prove the accuracy of the proposed model, I used the API RP11L method and Schafer...

Garcia, Julian Perez

2012-06-07

68

Power reduction by balancing sucker rod pumping unit with weight induced phase angle  

E-print Network

in the field. Although torque analysis is preformed frequently in the field today, counter weight placement is still being determined from tables. A computer program (PmpAna) is developed which gives quick and reliable information to the field technician... in the field. 3. Test this program in the field with actual data. 4. Add counter weights in the proper location in order to achieve an additional phase angle and study the results. PROGRAM METHODOLOGY PmpAna is a computer program that was developed...

Noack, Ernest Alan

2012-06-07

69

Effect of Suspended Sediment on Vulnerability of Young Razorback Suckers to Predation  

Microsoft Academic Search

The decline of native fishes in North America is principally a result of altered habitats, and the impact of mainstream dams has accounted for many of the habitat changes. Diminished turbidity, and introduced nonnative predators were investigated as possible reasons for the decline of endangered razorback suckers Xyrauchen texanus in the Colorado River. In laboratory tests, young razorback suckers selected

James E. Johnson; Robert T. Hines

1999-01-01

70

Singing Rod  

NSDL National Science Digital Library

How can a solid metal rod be made to emit a high-pitched squeal? This material is part of a series of hands-on science activities designed to arouse student interest. Here students investigate the resonance and acoustic properties that result from stroking a solid aluminum bar and causing it to resonate. The activity includes a description, a list of science process skills and complex reasoning strategies being used, and a compilation of applicable K-12 national science education standards. Also provided are content topics, a list of necessary supplies, instructions, and presentation techniques. The content of the activity is explained, and assessment suggestions are provided.

Mid-continent Research for Education and Learning (McREL); Jacobs, Steve

2004-01-01

71

Selenium impacts on razorback sucker, Colorado River, Colorado: I. Adults  

USGS Publications Warehouse

Adult razorback sucker (Xyrauchen texanus) were exposed to various selenium concentrations in ponds and isolated river channels of the Colorado River near Grand Junction, CO, to determine effects on their growth and residue accumulation over an 11-month period. Adults at Horsethief ponds were fed a commercial diet, whereas fish at Adobe Creek channel and North Pond foraged on natural food items. Selenium concentrations at Horsethief were 2.2 ??g/L in water, 0.1-1.4 ??g/g in sediment, and 2.3-3.1 ??g/g in food organisms (1.1 ??g/g in commercial fish food), at Adobe Creek were 3.8 ??g/L in water, 0.5-2.1 ??g/g in sediment, and 4-56 ??g/g in food organisms, and at North Pond were 9.5 ??g/L in water, 7-55 ??g/g in sediment, and 20-81 ??g/g in food organisms. The selenium concentrations in muscle plugs from adults at Adobe Creek (11.7 ??g/g, SD=0.4, n=6) and North Pond (16.6 ??g/g, SD=1.0, n=6) were greater than at Horsethief (4.5 ??g/g, SD=0.2, n=6). During a depuration period adults from Adobe Creek and North Pond lost 1-2% of their selenium burden in 32 days and 14-19% in 66 days. Selenium accumulated in razorback sucker above toxic thresholds reported in other studies, yet those residues were less than those reported in muscle plugs of 40% of wild razorback sucker caught in the Green River, Utah.

Hamilton, S.J.; Holley, K.M.; Buhl, K.J.; Bullard, F.A.; Weston, L.K.; McDonald, S.F.

2005-01-01

72

The effects of pulp mill effluent on the sex steroid binding protein in white sucker ( Catostomus commersoni) and longnose sucker ( C. catostomus)  

Microsoft Academic Search

The objective of this study was to characterize the effects of pulp mill effluent on the properties of the sex steroid binding protein (SBP) in the plasma of white sucker (Catostomus commersoni) and longnose sucker (C. catostomus). SBPs which specifically bind estradiol and testosterone with high affinity (kD?3 nM) and low capacity (Bmax?73–81 nM) were identified in both species. Subsequent

A. C Pryce-Hobby; M. E McMaster; L. M Hewitt; G Van Der Kraak

2003-01-01

73

Control rod cluster arrangement  

SciTech Connect

This patent describes a nuclear reactor including nuclear core which is cooled and moderated by light water, the nuclear core comprising a plurality of parallel arranged openings therethrough and interspersed among the fuel assemblies. A control rod cluster arrangement comprises load follow control rod cluster assemblies with each load follow control rod cluster assembly being adapted to slidingly fit within each of some of the fuel assemblies in the parallel arranged openings, the load follow control rod cluster assemblies each comprising a plurality of elongated parallel arranged rods attached to a single spider, and including a first group of rods and a second group of rods, the first group of rods and the second each consisting of a plurality of absorber rods. The first group of rods consist of absorber rods taken from the group consisting of B/sub 4/C, hafnium, or silver-indium-cadmium and the second group of rods consist of absorber rods each consisting of stainless steel, the first group of rods and the second group of rods each being integrally attached at all times to the single spider, the absorber rods of the second group of rods being dispersed throughout the control rod cluster assembly. The first group of rods have a first neutron capture cross section and the second group of rods have a second neutron capture cross section different from the first cross section.

Orr, W.L.; Doshi, P.K.; Mildrum, C.M.; Freeman, T.R.

1987-02-10

74

Control rod drive  

Microsoft Academic Search

A reactor core, one or more control rods, and a control rod drive are described for selectively inserting and withdrawing the one or more control rods into and from the reactor core, which consists of: a support structure secured beneath the reactor core; control rod positioning means supported by the support structure for movably supporting the control rod for movement

Hawke

1986-01-01

75

String vertex operators and cosmic strings  

NASA Astrophysics Data System (ADS)

We construct complete sets of (open and closed string) covariant coherent state and mass eigenstate vertex operators in bosonic string theory. This construction can be used to study the evolution of fundamental cosmic strings as predicted by string theory, and is expected to serve as a self-contained prototype toy model on which realistic cosmic superstring vertex operators can be based. It is also expected to be useful for other applications where massive string vertex operators are of interest. We pay particular attention to all the normalization constants, so that these vertices lead directly to unitary S-matrix elements.

Skliros, Dimitri; Hindmarsh, Mark

2011-12-01

76

Constraint Reasoning Over Strings  

NASA Technical Reports Server (NTRS)

This paper discusses an approach to representing and reasoning about constraints over strings. We discuss how many string domains can often be concisely represented using regular languages, and how constraints over strings, and domain operations on sets of strings, can be carried out using this representation.

Koga, Dennis (Technical Monitor); Golden, Keith; Pang, Wanlin

2003-01-01

77

The "Magic" String  

NSDL National Science Digital Library

The "Magic" String is a discrepant event that includes a canister with what appears to be the end of two strings protruding from opposite sides of it. Due to the way the strings are attached inside the canister, it appears as if the strings can magically

Hoover, Todd F.

2010-10-01

78

What is String Theory?  

Microsoft Academic Search

The first part is an introduction to conformal field theory and string perturbation theory. The second part deals with the search for a deeper answer to the question posed in the title. Contents: 1. Conformal Field Theory 2. String Theory 3. Vacua and Dualities 4. String Field Theory or Not String Field Theory 5. Matrix Models

Joseph Polchinski

1994-01-01

79

Evidence for string substructure  

SciTech Connect

The author argues that the behavior of string theory at high temperature and high longitudinal boosts, combined with the emergence of p-branes as necessary ingredients in various string dualities, point to a possible reformulation of strings, as well as p-branes, as composites of bits. He reviews the string-bit models, and suggests generalizations to incorporate p-branes.

Bergman, O.

1996-06-01

80

String-driven inflation  

NASA Technical Reports Server (NTRS)

It is argued that, in fundamental string theories, as one traces the universe back in time a point is reached when the expansion rate is so fast that the rate of string creation due to quantum effects balances the dilution of the string density due to the expansion. One is therefore led into a phase of constant string density and an exponentially expanding universe. Fundamental strings therefore seem to lead naturally to inflation.

Turok, Neil

1988-01-01

81

Control rod displacement  

Microsoft Academic Search

This patent describes a nuclear reactor including a core, cylindrical control rods, a single support means supporting the control rods from their upper ends in spaced apart positions and movable for displacing the control rods in their longitudinal direction between a first end position in which the control rods are fully inserted into the core and a second end position

Nakazato

1987-01-01

82

Demographics and 2008 Run Timing of Adult Lost River (Deltistes luxatus) and Shortnose (Chasmistes brevirostris) Suckers in Upper Klamath Lake  

USGS Publications Warehouse

We used capture-recapture data to assess population dynamics of endangered Lost River suckers (Deltistes luxatus) and shortnose suckers (Chasmistes brevirostris) in Upper Klamath Lake, Oregon. The Cormack-Jolly-Seber method was used to estimate apparent survival probabilities, and a temporal symmetry model was used to estimate annual seniority probabilities. Information theoretic modeling was used to assess variation in parameter estimates due to time, gender, and species. In addition, length data were used to detect multiple year-class failures and events of high recruitment into adult spawning populations. Survival of adult Lost River and shortnose suckers varied substantially across years. Relatively high annual mortality was observed for the lakeshore-spawning Lost River sucker subpopulation in 2002 and for the river spawning subpopulation in 2001. Shortnose suckers experienced high mortality in 2001 and 2004. This indicates that high mortality events are not only species specific, but also are specific to subpopulations for Lost River suckers. Seniority probability estimates and length composition data indicate that recruitment of new individuals into adult sucker populations has been sparse. The overall fitness of Upper Klamath Lake sucker populations are of concern given the low observed survival in some years and the paucity of recent recruitment. During most years, estimates of survival probabilities were lower than seniority probabilities, indicating net losses in adult sucker population abundances. The evidence for decline was more marked for shortnose suckers than for Lost River suckers. Our data indicated that sucker survival for both species, but especially shortnose suckers, was sometimes low in years without any observed fish kills. This indicates that high mortality can occur over a protracted period, resulting in poor annual survival, but will not necessarily be observed in association with a fish kill. A better understanding of the factors influencing adult survival and recruitment into spawning populations is needed. Monitoring these vital parameters will provide a quantitative means to evaluate population status and assess the effectiveness of conservation and recovery efforts.

Janney, Eric C.; Hayes, Brian S.; Hewitt, David A.; Barry, Patrick M.; Scott, Alta; Koller, Justin; Johnson, Mark; Blackwood, Greta

2009-01-01

83

Rod examination gauge  

SciTech Connect

The present invention is directed to a semi-automatic rod examination gauge for performing a large number of exacting measurements on radioactive fuel rods. The rod examination gauge performs various measurements underwater with remote controlled machinery of high reliability. The rod examination gauge includes instruments and a closed circuit television camera for measuring fuel rod length, free hanging bow measurement, diameter measurement, oxide thickness measurement, cladding defect examination, rod ovality measurement, wear mark depth and volume measurement, as well as visual examination. A control system is provided including a programmable logic controller and a computer for providing a programmed sequence of operations for the rod examination and collection of data.

Bacvinskas, W.S.; Bayer, J.E.; Davis, W.W.; Fodor, G.; Kikta, T.J.; Matchett, R.L.; Nilsen, R.J.; Wilczynski, R.

1991-12-31

84

Benzo[a]pyrene metabolism and excretion in white suckers with chronic liver diseases  

SciTech Connect

Wild white suckers (Catostomus commersoni) with diseased bile ducts excreted an oral dose of benzo[a]pyrene (BaP) into their bile as glucuronide, glutathione, and sulfo-conjugates at twice the rate of an unaffected reference population. BaP-hydroxylase (10% higher in the diseased population), glutathione-S-transferase (similar), or uridine-5[prime]-diphosphoglucuronic acid transferase (50% lower) levels did not correlate with these excretion rates. Metabolite levels were 57% higher in the liver of affected suckers than those in the liver of reference suckers, which might be due to bile retention within the diseased bile ducts. The bile duct disease affecting white suckers does not appear to restrict the metabolism and excretion of BaP.

Smith, I.R.; Kirby, G.M.; Ferguson, H.W.; Hayes, M.A. (Univ. of Guelph, Ontario (Canada))

1993-05-01

85

29 CFR 1919.81 - Examination of bulk cargo loading or discharging spouts or suckers.  

...portions of bulk cargo loading or discharging spouts or suckers which extend over vessels, together with any portable extensions, rigging components, outriggers, and attachment points supporting them or any of their components vertically, shall be examined...

2014-07-01

86

29 CFR 1919.81 - Examination of bulk cargo loading or discharging spouts or suckers.  

Code of Federal Regulations, 2010 CFR

... OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) GEAR CERTIFICATION Certification of Shore-Based Material Handling Devices § 1919.81 Examination of bulk cargo loading or discharging spouts or suckers....

2010-07-01

87

CHANGES IN GENETIC DIVERSITY OF A WHITE SUCKER POPULATION FOLLOWING EXPERIMENTAL WHOLE-LAKE ACIDIFICATION  

EPA Science Inventory

Despite great strides to reduce sulfur dioxide emissions over the last decade, acid precipitation remains a persistent threat to North American fish communities. A demographic analysis of white suckers in an experimentally acidified oligotrophic lake in northwest Ontario demonst...

88

Light from cosmic strings  

SciTech Connect

The time-dependent metric of a cosmic string leads to an effective interaction between the string and photons--the ''gravitational Aharonov-Bohm'' effect--and causes cosmic strings to emit light. We evaluate the radiation of pairs of photons from cosmic strings and find that the emission from cusps, kinks and kink-kink collisions occurs with a flat spectrum at all frequencies up to the string scale. Further, cusps emit a beam of photons, kinks emit along a curve, and the emission at a kink-kink collision is in all directions. The emission of light from cosmic strings could provide an important new observational signature of cosmic strings that is within reach of current experiments for a range of string tensions.

Steer, Daniele A.; Vachaspati, Tanmay [APC 10 rue Alice Domon et Leonie Duquet, 75205 Paris Cedex 13 (France); Physics Department, Arizona State University, Tempe, Arizona 85287 (United States)

2011-02-15

89

Fundamental strings in SFT  

E-print Network

In this letter we show that vacuum string field theory contains exact solutions that can be interpreted as macroscopic fundamental strings. They are formed by a condensate of infinitely many completely space-localized solutions (D0-branes).

Bonora, L; Santos, R J S; Tolla, D D

2005-01-01

90

Fundamental strings in SFT  

E-print Network

In this letter we show that vacuum string field theory contains exact solutions that can be interpreted as macroscopic fundamental strings. They are formed by a condensate of infinitely many completely space-localized solutions (D0-branes).

L. Bonora; C. Maccaferri; R. J. Scherer Santos; D. D. Tolla

2005-01-14

91

Fundamental strings in SFT  

Microsoft Academic Search

In this Letter we show that vacuum string field theory contains exact solutions that we propose to interpret as macroscopic fundamental strings. They are formed by a condensate of infinitely many completely space-localized solutions (D0-branes).

L. Bonora; C. Maccaferri; R. J. Scherer Santos; D. D. Tolla

2005-01-01

92

Quasiperiodicities in Fibonacci strings  

E-print Network

We consider the problem of finding quasiperiodicities in a Fibonacci string. A factor u of a string y is a cover of y if every letter of y falls within some occurrence of u in y. A string v is a seed of y, if it is a cover of a superstring of y. A left seed of a string y is a prefix of y that it is a cover of a superstring of y. Similarly a right seed of a string y is a suffix of y that it is a cover of a superstring of y. In this paper, we present some interesting results regarding quasiperiodicities in Fibonacci strings, we identify all covers, left/right seeds and seeds of a Fibonacci string and all covers of a circular Fibonacci string.

Christou, Michalis; Iliopoulos, Costas

2012-01-01

93

The Fraction String  

NSDL National Science Digital Library

In this lesson students create a model of a number line using string and adding machine tape. Students discover how to partition the string into equal sections, and name the fractional pieces, including fractions greater than 1.

Green, Michael

2012-06-26

94

Wave on a String  

NSDL National Science Digital Library

Watch a string vibrate in slow motion. Wiggle the end of the string and make waves, or adjust the frequency and amplitude of an oscillator. Adjust the damping and tension. The end can be fixed, loose, or open.

Simulations, Phet I.; Dubson, Michael; Adams, Wendy; Harlow, Danielle

2004-06-01

95

Spawning and Larva Drift of Sympatric Walleyes and White Suckers in an Ontario Stream  

Microsoft Academic Search

Walleyes Stizostedion vitreum vitreum and white suckers Catostomus commersoni shared a common spawning ground in Apsley Creek. Their reproduction overlapped in time, but white suckers spawned mainly in the riffle zone (710 eggs\\/m) and rarely in quiet water (0.5 eggs\\/m) surrounding the riffle. In contrast, walleyes spawned more in quiet water (6,241 eggs\\/m) than in the riffle (65 eggs\\/m). Walleye

B. W. Corbett; P. M. Powles

1986-01-01

96

Effect of suspended sediment on vulnerability of young razorback suckers to predation  

USGS Publications Warehouse

The decline of native fishes in North America is principally a result of altered habitats, and the impact of mainstream dams has accounted for many of the habitat changes. Diminished turbidity, and introduced nonnative predators were investigated as possible reasons for the decline of endangered razorback suckers Xyrauchen texanus in the Colorado River. In laboratory tests, young razorback suckers selected clear water over two water samples with higher concentrations of suspended sediment. In clear water, however, young razorback suckers were extremely susceptible to predation; native Colorado squawfish Ptychocheilus lucius consumed 90% of test razorback suckers, and nonnative green sunfish Lepomis cyanellus consumed 99.6%. As turbidity increased, razorback sucker predator avoidance improved and differences in predator success disappeared. Winter-spring spawning by razorback suckers in Lake Mohave, along with the extreme susceptibility of larvae to predation in clear water, may account for total recruitment failure in that lake. However, in upper basin rivers, suspended sediments remain high enough to limit predation by fishes tested, suggesting that other impacts, including contaminants and lack of floodplain habitat, may be thwarting recruitment in those rivers.

Johnson, J.E.; Hines, R.T.

1999-01-01

97

String theory: an update  

E-print Network

An overview of some of the developments in string theory over the past two years is given, focusing on four topics: realistic (standard model like) models from string theory, geometric engineering and theories with fluxes, the gauge theory-gravity correspondence, and time dependent backgrounds and string theory. Plenary talk at ICHEP'02, Amsterdam, July 24-31, 2002.

Jan de Boer

2002-10-23

98

Response of fish communities to different levels of white sucker ( Catostomus commersoni ) biomanipulation in five temperate lakes  

Microsoft Academic Search

The goal of this study was to evaluate the response of white sucker (Catostomus commersoni ), brook trout (Salvelinus fontinalis), and other fish species to the mass removal of white sucker in five Québec (Canada) lakes. White sucker removal ranged from 14.2 kg·ha-1 to 31.3 kg·ha-1 3 years after mass removal. In four of the study lakes, the proportion of

Philippe Brodeur; Pierre Magnan; Michel Legault

2001-01-01

99

Spontaneous formation of stringlike clusters and smectic sheets for colloidal rods confined in thin wedgelike gaps.  

PubMed

Monodispersed colloidal rods of ?-FeOOH with sizes ranging from 270 to 580 nm in length and 50 to 80 nm in width were synthesized. Narrow wedgelike gaps (0 to 700 nm in height) were formed around the inner bottom edge of the suspension glass cells. Optical microscopic observations revealed the formation of stringlike clusters of the rods and smectic sheets (by spontaneous side-by-side clustering of the strings) in the isotropic phase of the rod suspensions confined in narrow gaps; the electrolyte (HCl) concentrations of the suspensions are 5-40 mM, at which inter-rod interactions are attractive. The strings exhibit different colors that were used to investigate the structures of the strings with the help of interference color theory for thin films. The results are as follows. (1) The rods, lying flat on the gap bottom, are connected side-by-side and stacked upward to form stringlike clusters with different thicknesses depending on the gap height. (2) The stacking numbers (N(sr)) of the rods are estimated to be 1-5. With N(sr) increasing from 2 to 5, the volume fractions (?) of the rods in the strings increased typically from 0.25-0.3 to 0.35-0.42 to reach limiting values (close to the ? values of the rods in the bulk smectic phase). (3) Unexpected low-? strings are found in regions with an intermediate height in the gaps. These behaviors of ? may be caused by thermal fluctuations of the strings. PMID:23876087

Maeda, Hideatsu; Maeda, Yoshiko

2013-08-20

100

QCD String as AN Effective String  

NASA Astrophysics Data System (ADS)

There are two cases where QCD string is described by an effective theory of long strings: the static potential and meson scattering amplitudes in the Regge regime. I show how the former can be solved in the mean-field approximation, justified by the large number of space-time dimensions, and argue that it turns out to be exact for the Nambu-Goto string. By adding extrinsic curvature I demonstrate how the tachyonic instability of the ground-state energy can be cured by operators less relevant in the infrared. Based on the talks given at the NBI Summer Institute "Strings, gauge theory and the LHC", Copenhagen August, 22 - September, 02 2011 and the Workshop "Low dimensional physics and gauge principles", Yerevan September 21 - 26, 2011.

Makeenko, Y.

2013-11-01

101

Closest string with outliers  

PubMed Central

Background Given n strings s1, …, sn each of length ? and a nonnegative integer d, the CLOSEST STRING problem asks to find a center string s such that none of the input strings has Hamming distance greater than d from s. Finding a common pattern in many – but not necessarily all – input strings is an important task that plays a role in many applications in bioinformatics. Results Although the closest string model is robust to the oversampling of strings in the input, it is severely affected by the existence of outliers. We propose a refined model, the CLOSEST STRING WITH OUTLIERS (CSWO) problem, to overcome this limitation. This new model asks for a center string s that is within Hamming distance d to at least n – k of the n input strings, where k is a parameter describing the maximum number of outliers. A CSWO solution not only provides the center string as a representative for the set of strings but also reveals the outliers of the set. We provide fixed parameter algorithms for CSWO when d and k are parameters, for both bounded and unbounded alphabets. We also show that when the alphabet is unbounded the problem is W[1]-hard with respect to n – k, ?, and d. Conclusions Our refined model abstractly models finding common patterns in several but not all input strings. We initialize the study of the computability of this model and show that it is sensitive to different parameterizations. Lastly, we conclude by suggesting several open problems which warrant further investigation. PMID:21342588

2011-01-01

102

Selenium impacts on razorback sucker, Colorado: Colorado River: III. Larvae  

USGS Publications Warehouse

Razorback sucker (Xyrauchen texanus) larvae from adults exposed to selenium at three sites near Grand Junction, Colorado, for 9 months were used in a 30-day waterborne and dietary selenium study. Selenium concentrations in water averaged <1.6 ??g/L from 24-Road, 0.9 ??g/L from Horsethief, 5.5 ??g/L from Adobe Creek, and 10.7 ??g/L from the North Pond. Selenium in dietary items averaged 2.7 ??g/g in brine shrimp, 5.6 ??g/g in zooplankton from Horsethief east wetland, 20 ??g/g in zooplankton from Adobe Creek, and 39 ??g/g in zooplankton from North Pond. The lowest survival occurred in larvae fed zooplankton rather than brine shrimp. Survival of larvae at Adobe Creek and North Pond was lower in site water than in reference water. Survival of brood stock larvae was higher than Horsethief larvae even though they received the same water and dietary treatments. Arsenic concentrations in brine shrimp may have resulted in an antagonistic interaction with selenium and reduced adverse effects in larvae. Deformities in larvae from North Pond were similar to those reported for selenium-induced teratogenic deformities in other fish species. Selenium concentrations of ???4.6 ??g/g in food resulted in rapid mortality of larvae from Horsethief, Adobe Creek, and North Pond, and suggested that selenium toxicity in the Colorado River could limit recovery of this endangered fish.

Hamilton, S. J.; Holley, K. M.; Buhl, K. J.; Bullard, F. A.

2005-01-01

103

Selenium impacts on razorback sucker, Colorado River, Colorado: II. Eggs  

USGS Publications Warehouse

Effects on hatching and development of fertilized eggs in adult razorback sucker (Xyrauchen texanus) exposed to selenium in flooded bottomland sites near Grand Junction, Colorado, were determined. After 9 months exposure, fish were collected and induced to spawn and eggs collected for inorganic element analyses. A 9-day egg study was conducted with five spawns from Horsethief ponds, six spawns from Adobe Creek channel, and four spawns from North Pond using a reference water and site waters. Selenium concentrations in eggs were 6.5 ??g/g from Horsethief, 46 ??g/g from Adobe Creek, 38 ??g/g from North Pond, and 6.0 ??g/g from brood stock. Eggs from young adults had a smaller diameter and higher moisture content than brood stock. There were no differences among the four sources in viability, survival, hatch, hatchability, or mortality of deformed embryos or larvae. Adobe Creek larvae had more deformed embryos in eggs held in site water than held in reference water. There were significant negative correlations between selenium concentrations in adult muscle plugs and percent hatch, egg diameter, and deformities in embryos. Results from this study suggest that selenium contamination in parts of the upper basin of the Colorado River should be a major concern to recovery efforts for endangered fish.

Hamilton, S.J.; Holley, K.M.; Buhl, K.J.; Bullard, F.A.

2005-01-01

104

Virtual strings and their cobordisms  

Microsoft Academic Search

A virtual string is a scheme of self-intersections of a closed curve on a surface. We study algebraic invariants of strings as well as two equivalence relations on the set of strings: homotopy and cobordism. We show that the homotopy invariants of strings form an infinite dimensional Lie group. We also discuss connections between virtual strings and virtual knots.

Vladimir Turaev

2003-01-01

105

Evolutionary Divergence of Duplicate Copies of the Growth Hormone Gene in Suckers (Actinopterygii: Catostomidae)  

PubMed Central

Catostomid fishes (suckers) have duplicate copies of the growth hormone gene and other nuclear genes, due to a genome duplication event early in the group’s history. Yet, paralogs of GH in suckers are more than 90% conserved in nucleotide (nt) and amino acid (aa) sequence. Within paralogs across species, variation in nt and aa sequence averages 3.33% and 4.46% for GHI, and 3.22% and 2.43% for GHII, respectively. Selection tests suggest that the two GH paralogs are under strong purifying selection. Consensus trees from phylogenetic analysis of GH coding region data for 23 species of suckers, other cypriniform fishes and outgroups resolved cypriniform relationships and relationships among GHI sequences of suckers more or less consistently with analyses based on other molecular data. However, the analysis failed to resolve all sucker GHI and GHII sequences as monophyletic sister groups. This unexpected topology did not differ significantly from topologies constrained to make all GH sequences monophyletic. We attribute this result either to limitations in our GHII data set or convergent adaptive changes in GHII of tribe Catostomini. PMID:20480002

Bart, Henry L.; Reneau, Paulette C.; Doosey, Michael H.; Bell, Charles D.

2010-01-01

106

Assessment of status of white sucker (Catostomus commersoni) populations exposed to bleached kraft pulp mill effluent.  

PubMed

Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to investigate population dynamics for white sucker (Catostomus commersoni) exposed to pulp mill effluent at a well-studied site in Jackfish Bay, Lake Superior, Canada. The model uniquely combines a Leslie population projection matrix and the logistic equation to translate changes in the fecundity and the age structure of a breeding population of white sucker exposed to pulp mill effluent to alterations in population growth rate. Application of this density-dependent population projection model requires construction of a life table for the organism of interest, a measure of carrying capacity, and an estimation of the effect of stressors on vital rates. A white sucker population existing at carrying capacity and subsequently exposed to pulp mill effluent equivalent to a documented exposure experienced during the period 1988 to 1994 in Jackfish Bay would be expected to exhibit a 34% to 51% annual decrease in recruitment during the first 5 yr of exposure and approach a population size of 71% of carrying capacity. The Jackfish Bay study site contains monitoring data for biochemical endpoints in white sucker, including circulating sex steroid concentrations, that could be combined with population modeling to utilize the model demonstrated at the Jackfish Bay study site for investigation of other white sucker populations at sites that are less data-rich. PMID:23504660

Miller, David H; Tietge, Joseph E; McMaster, Mark E; Munkittrick, Kelly R; Xia, Xiangsheng; Ankley, Gerald T

2013-07-01

107

Nonlocality in string theory  

NASA Astrophysics Data System (ADS)

We discuss an aspect of string theory which has been tackled from many different perspectives, but incompletely: the role of nonlocality in the theory and its relation to the geometric shape of the string. In particular, we will describe in quantitative terms how one can zoom out from an extended object such as a string in such a way that, at sufficiently large scales, it appears structureless. Since there are no free parameters in free-string theory, the notion of large scales will be unambiguously determined. In other words, we will be able to answer the question: how and at which scale can the string be seen as a particle? In doing so, we will employ the concept of spectral dimension in a new way with respect to its usual applications in quantum gravity. The operational notions of worldsheet and target spacetime dimension in string theory are also clarified and found to be in mutual agreement.

Calcagni, Gianluca; Modesto, Leonardo

2014-09-01

108

Nonlocality in string theory  

E-print Network

We discuss an aspect of string theory which has been tackled from many different perspectives, but incompletely: the role of nonlocality in the theory and its relation to the geometric shape of the string. In particular, we will describe in quantitative terms how one can zoom out from an extended object such as the string in such a way that, at sufficiently large scales, it appears structureless. Since there are no free parameters in free-string theory, the notion of large scales will be unambiguously determined. In other words, we will be able to answer the question: How and at which scale can the string be seen as a particle? In doing so, we will employ the concept of spectral dimension in a new way with respect to its usual applications in quantum gravity. The operational notions of worldsheet and target spacetime dimension in string theory are also clarified and found to be in mutual agreement.

Gianluca Calcagni; Leonardo Modesto

2013-10-18

109

Topics in String Phenomenology  

E-print Network

We consider two questions in string ``phenomenology.'' First, are there any generic string predictions? Second, are there any general lessons which string theory suggests for thinking about low energy models, particularly in the framework of supersymmetry? Among the topics we consider are the squark and slepton spectrum, flavor symmetries, discrete symmetries including $CP$, and Peccei-Quinn symmetries. We also note that in some cases, discrete symmetries can be used to constrain the form of supersymmetry breaking.

Michael Dine

1993-09-23

110

Segregation by species and size classes of rainbow trout, Salmo gairdneri , and Sacramento sucker, Catostomus occidentalis , in three California streams  

Microsoft Academic Search

Synopsis The hypothesis that Sacramento suckers, Catostomus occidentalis, compete with rainbow trout, Salmo gairdneri, for space in streams was examined by measuring microhabitat utilization of both species in three California streams. Two streams were similar in most respects except one contained only trout and one contained trout and a large population of suckers. The third stream, formed by the union

Donald M. Baltz; Peter B. Moyle

1984-01-01

111

Spatial structuring of length-at-age of the benthivorous white sucker ( Catostomus commersoni ) in relation to environmental variables  

Microsoft Academic Search

Great variations were observed in length-at-age among populations of white sucker, Catostomus commersoni, in 32 Ontario lakes. The spatial structuring of these data was examined using the Mantel test with respect to the corresponding spatial structuring for various environmental variables which might affect growth of the white sucker. These environmental variables include lake geographic location, lake morphometry, water chemistry, food

Yong Chen; Harold H. Harvey

1999-01-01

112

Intraspecific genetic structure of white sucker ( Catostomus commersoni ) in northeastern North America as revealed by mitochondrial DNA polymorphism  

Microsoft Academic Search

Restriction fragment length polymorphisms in mitochondrial DNA (mtDNA) were used to study the influence of Pleistocene glaciations on the intraspecific genetic structure and distribution of the white sucker (Catostomus commersoni )i n northeastern North America. A total of 312 white sucker from 13 populations, including a population of dwarf ecotypes (Catostomus commersoni utawana), were analysed. An average of 93 fragments

Pascale Lafontaine; Julian J. Dodson

1997-01-01

113

Regression, proliferation and development of lip papillomas in wild white suckers, Catostomus commersoni , held in the laboratory  

Microsoft Academic Search

Epizootics of skin neoplasms in teleost species have been documented within the Great Lakes region over the last decade. The white sucker,Catostomus commersoni, has been proposed as a sentinel species to monitor environmental health in these systems. The prevalence of skin neoplasia is elevated in white suckers and other fish taken from chemically polluted sites or from lake regions adjacent

Peter D. Premdas; Chris D. Metcalfe

1994-01-01

114

The Prevalence and Histological Appearance of Lip Papillomas in White Suckers ( Catostomus commersoni) from Two Sites in Central Ontario, Canada  

Microsoft Academic Search

The white sucker, Catostomus commersoni (Lacapede), has been proposed as a sentinel species to monitor environmental health in the Great Lakes. In a population of white suckers spawning in the Ganaraska River, Lake Ontario (Port Hope, Ontario) there was an elevated prevalence of lip papillomas (46%), body papillomas (1.4%), and mucoid plaques (47%) compared to an inland reference population from

Peter D. Premdas; Tracy L. Metcalfe; Maritza E. Bailey; Chris D. Metcalfe

1995-01-01

115

Diurnal Activity of the Common Sucker, Catostomus Commersonnii (Lacépède), and the Rock Bass, Ambloplites Rupestris (Rafinesque), in Muskellunge Lake  

Microsoft Academic Search

Gill nets set in Muskellunge Lake, Vilas County, Wisconsin, were examined at 2- to 4-hour intervals throughout ten 24-hour periods during the summers of 1933 to 1937 to determine the activity of suckers and rock base during the day and night.The rate at which suckers were captured at depths around 6 meters was highest during the periods 3 to 5

William A. Spoor; Clarence L. Schloemer

1939-01-01

116

THE EFFECT OF EXERCISE ON THE CARDIAC OUTPUT AND BLOOD FLOW DISTRIBUTION OF THE LARGESCALE SUCKER CATOSTOMUS MACROCHEILUS  

Microsoft Academic Search

Summary Cardiac output (Q. ) and blood flow distribution were measured in adult largescale suckers at rest and while swimming. Cardiac output was directly measured using an ultrasonic flowprobe in f ish during the summer (16?C), fall (10?C) and winter (5?C). Largescale suckers were adept at holding station against a current without swimming and, when engaged in this behavior, they

ALAN S. KOLOK; R. MICHAEL SPOONER; ANTHONY P. FARRELL

117

Biological Characteristics of the Blue Sucker in the James River and the Big Sioux River, South Dakota  

Microsoft Academic Search

Little is known about the relative abundance and biology of the blue sucker (Cycleptus elongatus), a species that may be declining in some parts of its range. We described the age, growth, condition, length distribution, and habitat preference of the blue sucker in two South Dakota rivers. Specimens were collected from the James River (n=74) and Big Sioux River (n=28)

Nathan M. Morey; Charles R. Berry Jr

2003-01-01

118

Demographics and Chronology of a Spawning Aggregation of Blue Sucker (Cycleptus elongatus) in the Grand River, Missouri, USA  

Microsoft Academic Search

The blue sucker (Cycleptus elongatus) was sampled as individuals arrived, spawned, and departed from a spawning rime in the Grand River of northcentral Missouri, USA. The Grand River basin was not known to support blue sucker reproduction with few individuals ever recorded. The spawning site is unique in character for the lower river. Individuals began arriving in early April when

Jason C. Vokoun; Travis L. Guerrant; Charles F. Rabeni

2003-01-01

119

Use of Constructed Side Channels of the Missouri River (Nebraska) by Age0 Blue Sucker (Cycleptus elongatus)  

Microsoft Academic Search

The blue sucker (Cycleptus elongatus) is listed as threatened in the state of Nebraska, and little is known about its life history. Nebraska Game and Parks Commission monitoring crews collected 13 age-0 blue suckers in three constructed side channels of the Missouri River from 2006 to 2008. Eleven of the 13 fish were sampled in shallow areas (<0.6 m) associated

Brandon L. Eder

2009-01-01

120

Determination of Upper Temperature Tolerance in June Sucker Larvae: Is the Transition to Utah Lake Temperatures a Recruitment Bottleneck?  

Microsoft Academic Search

The June sucker Chasmistes liorus is an endangered adfluvial fish species that is endemic to the Utah Lake basin. This species remains endangered due to a lack of recruitment. Anthropogenic changes to June sucker lotic and lentic habitat has likely led to recruitment failure. Changes to Utah Lake include increased water temperature, increased turbidity, and eutrophic and saline conditions. The

Kevin M. Kappenman; Molly A. H. Webb; Elijah S. Cureton; Jason Ilgen

2010-01-01

121

Effects of prey density on growth and survival of white sucker, Catostomus commersoni , and pumpkinseed, Lepomis gibbosus , larvae  

Microsoft Academic Search

Growth and survival of white sucker and pumpkinseed larvae were examined in the laboratory in relation to prey density. Mortality of both species was greatest during the transition from endogenous to exogenous nutrition. Mortality prior to yolk absorption was substantial for white suckers and was not related to prey density whereas, pumpkinseed mortality during the same period was low. After

Thomas F. Hart; Robert G. Werner

1987-01-01

122

Sperm quality assessments for endangered razorback suckers Xyrauchen Texanus  

USGS Publications Warehouse

Flow cytometry (FCM) and computer-assisted sperm motion analysis (CASA) methods were developed and validated for use with endangered razorback suckers Xyrauchen texanus collected (n=64) during the 2006 spawning season. Sperm motility could be activated within osmolality ranges noted during milt collections (here 167–343 mOsm/kg). We hypothesized that sperm quality of milt collected into isoosmotic (302 mOsm/kg) or hyperosmotic (500 mOsm/kg) Hanks' balanced salt solution would not differ. Pre-freeze viabilities were similar between osmolalities (79%±6 (S.E.M.) and 76%±7); however, post-thaw values were greater in hyperosmotic buffer (27%±3 and 12%±2; P=0.0065), as was mitochondrial membrane potential (33%±4 and 13%±2; P=0.0048). Visual estimates of pre-freeze motility correlated with total (r=0.7589; range 23–82%) and progressive motility (r=0.7449) by CASA and were associated with greater viability (r=0.5985; Pr=-0.83; P=0.0116) and mitochondrial function (r=-0.91; P=0.0016). By FCM-based assessments of DNA integrity, whereby increased fluorochrome binding indicated more fragmentation, higher levels were negatively correlated with count (r=-0.77; Pr=-0.66; P=0.0004). Fragmentation was higher in isotonic buffer (P=0.0234). To increase reproductive capacity of natural populations, the strategy and protocols developed can serve as a template for use with other imperiled fish species, biomonitoring, and genome banking.

Jenkins, Jill A.; Eilts, Bruce E.; Guitreau, Amy M.; Figiel, Chester R.; Draugelis-Dale, Rassa O.; Tiersch, Terrence R.

2011-01-01

123

Airplane on a String  

NSDL National Science Digital Library

Students analyze the motion of a toy airplane on a string using information from the video (a visible force scale, a frame-counter & an overlaid protractor). These measurments allow them to determine the mass and speed of the aircraft as well as the length of the string that constrains it.

Vonk, Matt

124

The String Deviation Equation  

E-print Network

The relative motion of many particles can be described by the geodesic deviation equation. This can be derived from the second covariant variation of the point particle's action. It is shown that the second covariant variation of the string action leads to a string deviation equation.

Mark D. Roberts

1998-10-13

125

Elements of string cosmology  

Microsoft Academic Search

Aspects of string cosmology for critical and non-critical strings are discussed emphasizing the necessity to account for the dilaton dynamics for a proper incorporation of ``large-small'' duality. This drastically modifies the intuition one has with Einstein's gravity. For example winding modes, even though contributing to the energy density, oppose expansion and if not annihilated will stop the expansion. Moreover we

A. A. Tseytlin; C. Vafa

1992-01-01

126

Extreme Cosmic String  

E-print Network

This paper deals with the geometry of supermassive cosmic strings. We have used an approach that enforces the spacetime of cosmic strings to also satisfy the conservation laws of a cylindric gravitational topological defect, that is a spacetime kink. In the simplest case of kink number unity, the entire energy range of supermassive strings becomes then quantized so that only cylindrical defects with linear energy density $G\\mu=1/4$ (critical string) and $G\\mu=1/2$ (extreme string) are allowed to occur in this range. It has been seen that the internal spherical coordinate $\\theta$ of the string metric embedded in an Euclidean three-space also evolves on imaginary values, leading to the creation of a covering shell of broken phase that protects the core with trapped energy, even for $G\\mu=1/2$. Then the conical singularity becomes a removable horizaon singularity. We re-express the extreme string metric in the Finkelstein- McCollum standard form and remove the geodesic incompleteness by using the Kruskal technique. The z=const. sections of the resulting metric are the same as the hemispherical section of the metric of a De Sitter kink. Some physical consequences from these results, including the possibility that the extreme string drives inflation and thermal effects in its core, are also discussed.

P. F. Gonzalez-Diaz

1995-08-28

127

Cosmological Cosmic Strings.  

National Technical Information Service (NTIS)

The effect of an infinite cosmic string on a cosmological background is investigated. It is found that the metric is approximately a scaled version of the empty space string metric, i.e., conical in nature. Results are used to place bounds on the amount o...

R. Gregory

1988-01-01

128

String Mediated Phase Transitions.  

National Technical Information Service (NTIS)

It is demonstrated from first principles how the existence of string-like structures can cause a system to undergo a phase transition. In particular, the role of topologically stable cosmic string in the restoration of spontaneously broken symmetries is e...

E. Copeland, D. Haws, R. Rivers, S. Holbraad

1988-01-01

129

Pull rod assembly  

DOEpatents

A pull rod assembly comprising a pull rod having three peripheral grooves, a piston device including an adaptor ring and a seal ring, said piston device being mounted on the pull rod by a split ring retainer situated in one groove and extending into an interior groove in the adaptor and a resilient split ring retained in another groove and positioned to engage the piston device and to retain the seal on its adaptor.

Cioletti, Olisse C. (Pittsburgh, PA)

1990-01-01

130

Coalescence of two viscoelastic droplets connected by a string  

NASA Astrophysics Data System (ADS)

A new type of coalescence of viscoelastic droplets is described and analyzed. A viscoelastic drop of polyisobutene (PIB) containing high molar mass PIB (HPIB), suspended in polydimethylsiloxane, is separated into two droplets connected by a string, which is called "bead-string-bead" (BSB), through repeated elongation and relaxation in a four-roll mill rheometer. Upon flow cessation, the two drops are pulled to approach each other by the string and eventually coalesce. This process exhibits interesting features: The string remains stable like a rod without capillary breakup; the string length and the merging force decay exponentially with time; the string diameter may not change significantly through the approach. The string in BSB is more stable than that of the capillary thinning process of beads on string in jet or fixed-end rheometer. These phenomena are modeled based on the force balance of the viscoelasticity of HPIB systems, viscous drag, and the Laplace force. The model prediction agrees with the experimental observation reasonably well, revealing the viscoelastic nature of the coalescence of two droplets. The characteristic time of drop approach is comparable to that of the pulling stress decay. The condition of keeping a constant diameter in BSB approach creates a status where both drop approach and stress decay exponentially with the same characteristic time, which is comparable to the material relaxation time. This case allows the model to analyze the relationships between critical string diameter and the material parameter as well as the process parameters and to discuss the microscopic images of the BSB process.

Yang, Jianmao; Xu, Yuanze

2008-04-01

131

Control rod position indication system  

SciTech Connect

An axial rod position determination system is described for a control rod in a nuclear reactor core, said system comprising: fixed incore detectors; analytical, on-line signature means for periodically creating a response signature database of expected detector response deviations for assumed rod positions from a reference detector response produced at the current rod position by said fixed incore detectors; and rod position determination means for continuously determining a moved rod position of the control rod by scanning the signature database for a signature match between the expected detector response deviations and current detector response deviations produced by said fixed incore detectors with the control rod at the moved rod position.

Impink, A.J. Jr.; Heibel, M.D.; Grobmyer, L.R.

1993-07-20

132

Music: Beginning Strings, Instrumental Techniques--Strings.  

ERIC Educational Resources Information Center

A course in introduction to music emphasizing modes and forms is presented. The approach used is a laboratory one in which pupils will develop skill in playing string instruments, sing, listen to, read and compose music with emphasis on identification of elementary concepts of mode and form. Course objectives include: (1) The pupil will select the…

Biringer, Frank A., Jr.; Ronci, Sal

133

Calibration of rod position indicators  

Microsoft Academic Search

This patent describes a procedure for calibration of a rod position indicator in a nuclear reactor having movable control rods without total shutdown of the reactor. It comprises: noting that the indicated position of a rod differs from a demand position of the rod by an extent exceeding a predetermined error range, determining that the rod is actually within the

A. P. Ginsberg; J. P. Mooney

1991-01-01

134

Split string field theory I  

Microsoft Academic Search

We describe projection operators in the matter sector of Witten's cubic string field theory using modes on the right and left halves of the string. These projection operators represent a step towards an analytic solution of the equations of motion of the full string field theory, and can be used to construct Dp-brane solutions of the string field theory when

David J. Gross; Washington Taylor

2001-01-01

135

Early ontogeny of white sucker, Catostomus commersoni , with steps of saltatory development  

Microsoft Academic Search

Frequent and detailed observations of arbitrary stages revealed a saltatory pattern of development in the early ontogeny of fluvial spawning white sucker. Considered as adaptations for respiration were: i) expansion of the surface area of the yolk through a change in yolk shape, ii) the presence of carotenoid pigment in the yolk, iii) a large caudal vein sinus, iv) coverage

James F. McElman; Eugene K. Balon

1980-01-01

136

Relationship of River Pollution to Bacterial Infection in Salmon (Salmo salar) and Suckers (Catostomus commersoni)  

Microsoft Academic Search

During the summers of 1967 and 1968, the bacterium, Aeromonas liquefaciens, was involved in disease of Atlantic salmon (Salmo salar) and suckers (Catostomus commersoni) in the Miramichi River, New Brunswick. A surge of copper and zinc pollution in late June 1967, and high river temperatures enhanced production of an epizootic. The epizootic recurred during the summer of 1968.

John H. C. Pippy; Gerard M. Hare

1969-01-01

137

WHITE SUCKER 'CATOSTOMUS COMMERSONI' EMBRYO DEVELOPMENT, AND EARLY GROWTH AND SURVIVAL AT DIFFERENT TEMPERATURES  

EPA Science Inventory

White suckers (Catostomus commersoni) were exposed from fertilization through hatching to seven constant temperatures from 6.2 through 24.1C. High percentages of apparently normal larvae hatched at temperatures from 9.0 through 17.2C. Maximum percent hatch occurred at 15.2C, whil...

138

Endogenous lunar rhythm in the behavioural thermoregulation of a teleost fish, the white sucker, Catostomus commersoni  

Microsoft Academic Search

The white sucker, Catostomus commersoni, displays a diel rhythm of behavioural thermoregulation in a horizontal thermal gradient. Under LD 12: 12 single fish select significantly higher temperatures in the scotophase than in the photophase. An endogenous lunar rhythm exists in the absolute and maximum and minimum temperatures selected. Significantly higher temperatures (+2°C) are selected at the times of the new

Martin Kavaliers

1982-01-01

139

Drift ecology of western catostomid larvae with emphasis on Warner suckers, Catostomus warnerensis (Teleostei)  

Microsoft Academic Search

We studied drift ecology of Warner sucker, Catostomus warnerensis, larvae in streams of Warner Valley, Oregon in 1992 and 1993 in part to determine whether downstream transport of larvae limits juvenile recruitment. Variation in runoff for the two years was extreme, where peak discharge in 1992 was two orders of magnitude lower than peak discharge in 1993. We deployed drift

Tom B. Kennedy; Gary L. Vinyard

1997-01-01

140

Toxicity of selenium and other elements in food organisms to razorback sucker larvae  

Microsoft Academic Search

Elevated selenium concentrations documented in water, sediment, and biota in irrigation drain water studies by U.S. Department of the Interior agencies and academia have raised concerns that selenium may be adversely affecting endangered fish in the upper Colorado River basin. The objective of the study was to determine the effects on endangered razorback sucker (Xyrauchen texanus) larvae from exposure to

Steven J Hamilton; Kathy M Holley; Kevin J Buhl; Fern A Bullard; L. Ken Weston; Susan F McDonald

2002-01-01

141

First Food of Larval Yellow Perch, White Sucker, Bluegill, Emerald Shiner, and Rainbow Smelt  

Microsoft Academic Search

Entire digestive tract contents from larval yellow perch [Perca flavescens (Mitchill)], white sucker [Catostomus commersoni (Lacepede)], bluegill (Lepomis macrochirus Rafinesque), emerald shiner (Notropis (atherinoides Rafinesque), and rainbow smelt [Osmerus mordax (Mitchill)], along with plankton samples taken concurrently with fish samples, were identified and counted. Food selection was calculated by use of Ivlev's electivity index. First food of yellow perch from

Richard E. Siefert

1972-01-01

142

Life history of the bridgelip sucker in the central Columbia River  

Microsoft Academic Search

In the central Columbia River, southeastern Washington, bridgelip suckers (Catostomus columbianus) were common in deep water with strong currents during daylight and moved into slower shallow water at night. Mean calculated fork lengths (FL) in millimeters at annulus formation were age I, 63; II, 148; III, 224; IV, 291; V, 335; VI, 361; VII, 387; VIII, 401; IX, 408. Back

DENNIS D. DAUBLE

1980-01-01

143

Life History of the Bridgelip Sucker in the Central Columbia River  

Microsoft Academic Search

In the central Columbia River, southeastern Washington, bridgelip suckers (Catostomus columbianus) were common in deep water with strong currents during daylight and moved into slower shallow water at night. Mean calculated fork lengths (FL) in millimeters at annulus formation were age I, 63; II, 148; III, 224; IV, 291; V, 335; VI, 36I; VII, 387; VIII, 401; IX, 408. Back-calculated

Dennis D. Dauble

1980-01-01

144

EXPLOITATION OF FLOODPLAIN RESOURCES BY ADULT LARGESCALE SUCKER OF THE WILLAMETTE RIVER, OREGON  

EPA Science Inventory

We tested two predictions of the flood-pulse concept on a large, temperate alluvial river that historically flooded an extensive fringing floodplain. We predicted adult largescale sucker, Catostomus macrocheilus, would: (1) migrate onto the floodplain during high water; and (2) e...

145

Life history of the bridgelip sucker in the central Columbia River  

SciTech Connect

In the central Columbia River, southeastern Washington, bridgelip suckers (Catostomus columbianus) were common in deep water with strong currents during daylight and moved into slower shallow water at night. Mean calculated fork lengths (FL) in millimeters at annulus formation were age I, 63; II, 148; III, 224; IV, 291; V, 335; VI, 361; VII, 387; VIII, 401; IX, 408. Back calculated lengths approximated lengths at capture for respective ages. The length-weight (W) relationship for both sexes was log/sub e/W = -12.65 + 3.25 log/sub e/FL. Both sexes reached maturity at about 350 mm FL and age VI. Peak spawning in all years occurred during May in water temperatures of 8 to 13 C. Breeding males and females both exhibited a narrow red lateral line stripe. Estimated egg numbers per mature female ranged from 9,995 to 21,040. Bridgelip sucker diet was almost entirely periphyton, except fish smaller than 150 mm FL utilized mainly aquatic insect larvae and zooplankton. Variability of taxonomic characters caused some difficulty in distinguishing bridgelip suckers from sympatric largescale suckers (C. macrocheilus).

Dauble, D.D.

1980-01-01

146

Estimating Geographic Variation in Allometric Growth and Body Condition of Blue Suckers with Quantile Regression  

Microsoft Academic Search

Increasing our understanding of how environmental factors affect fish body condition and improving its utility as a metric of aquatic system health require reliable estimates of spatial variation in condition (weight at length). We used three statistical approaches that varied in how they accounted for heterogeneity in allometric growth to estimate differences in body condition of blue suckers Cycleptus elongatus

Brian S. Cade; James W. Terrell; Ben C. Neely

2011-01-01

147

Effects of Ambient Water Quality on the Endangered Lost River Sucker in Upper Klamath Lake, Oregon  

Microsoft Academic Search

Populations of the Lost River sucker Deltistes luxatus have declined so precipitously in the Upper Klamath Basin of Oregon and California that this fish was recently listed for federal protection as an endangered species. Although Upper Klamath Lake is a major refuge for this species, fish in the lake occasionally experience mass mortalities during summer and early fall. This field

Barbara A. Martin; Michael K. Saiki

1999-01-01

148

Oxidative Stress and Bioindicators of Reproductive Function in Pulp and Paper Mill Effluent Exposed White Sucker  

Microsoft Academic Search

This study investigates oxidative stress and bioindicators of reproductive function in wild white sucker (Catostomus commer- soni) collected from environments receiving pulp and paper mill effluent discharges in northern Ontario. Samples were collected over an eight-year period adjacent to three pulp and paper mills using a variety of processing and bleaching techniques. Fish col- lected downstream of pulp and paper

Ken D. Oakes; Mark E. McMaster; Andrea C. Pryce; Kelly R. Munkittrick; Cam B. Portt; L. Mark Hewitt; Dan D. MacLean; Glen J. Van Der Kraak

2003-01-01

149

Cosmological cosmic strings  

NASA Technical Reports Server (NTRS)

The effect of an infinite cosmic string on a cosmological background is investigated. It is found that the metric is approximately a scaled version of the empty space string metric, i.e., conical in nature. Results are used to place bounds on the amount of cylindrical gravitational radiation currently emitted by such a string. The gravitational radiation equations are then analyzed explicitly and it is shown that even initially large disturbances are rapidly damped as the expansion proceeds. The implications of the gravitational radiation background and the limitations of the quadrupole formula are discussed.

Gregory, Ruth

1988-01-01

150

Effective string theory simplified  

NASA Astrophysics Data System (ADS)

In this note we simplify the formulation of the Poincaré-invariant effective string theory in D dimensions by adding an intrinsic metric and embedding its dynamics into the Polyakov formalism. We use this formalism to classify operators order-by-order in the inverse physical length of the string, in a fully gauge-invariant framework. We then use this classification to analyze the universality and nonuniversality of observables, up to and including the second sub-leading order in the long string expansion.

Hellerman, Simeon; Maeda, Shunsuke; Maltz, Jonathan; Swanson, Ian

2014-09-01

151

Control rod velocity limiter  

Microsoft Academic Search

This patent describes a velocity control arrangement for a reciprocable, vertically oriented control rod for use in a nuclear reactor in a fluid medium, the control rod including a drive hub secured to and extending from one end therefrom. The control device comprises: a toroidally shaped control member spaced from and coaxially positioned around the hub and secured thereto by

J. E. Cearley; J. C. Carruth; R. C. Dixon; S. S. Spencer; J. A. Jr. Zuloaga

1986-01-01

152

HYDRAULIC CONTROL ROD ACTUATOR  

Microsoft Academic Search

An investigation was made of the conceptual feasibility and production ; of a prototype model of a Hydraulic Control Rod Drive Mechanism that utilizes ; primary reactor water as the hydraulic fluid and is sealed within the reactor ; pressure vessel. It is capable of controlling 2300-pound rods such as might be ; used in large pressurized-water reactors. By utilizing

R. B. Hussey; C. F. Cartledge

1963-01-01

153

Control rod housing alignment  

Microsoft Academic Search

This patent describes a process for measuring the vertical alignment between a hole in a core plate and the top of a corresponding control rod drive housing within a boiling water reactor. It comprises: providing an alignment apparatus. The alignment apparatus including a lower end for fitting to the top of the control rod drive housing; an upper end for

R. C. Dixon; G. A. Deaver; J. R. Punches; G. E. Singleton; J. G. Erbes; H. P. Offer

1990-01-01

154

Nonassociativity in string theory  

NASA Astrophysics Data System (ADS)

I summarize some of the ideas and motivations behind a recently performed conformal field theory analysis of closed strings in three-form flux backgrounds. This suggests an underlying nonassociative structure for the coordinates.

Blumenhagen, Ralph

2013-10-01

155

Quasimomenta of string configurations  

NASA Astrophysics Data System (ADS)

We sketch a reciprocal space analogue of the combinatorial bijection of Robinson- Schensted and Kerov-Kirillov-Reshetikhin (RSKKR) between magnetic configurations (the initial basis for quantum calculations of the eigenproblem of the Heisenberg Hamiltonian for a one-dim finite Heisenberg chain), and rigged string configurations (the classification labels for the exact results of Bethe Ansatz). Existence of such a bijection admits an interpretation of the exact quantum numbers of riggings as quasimomenta of l-strings. The extended size of an l-string results in selection rules for these quasimomenta, and thus in a division of the Brillouin zone into compact subzones of forbidden and allowed states of the system of coupled Bethe pseudoparticles. The forbidden Brillouin subzone for a particular l-string is evidently the effect of kinematical restrictions for motions of constituent Bethe pseudoparticles. These restrictions can be easily predicted in a combinatorially unique way due to completness of the RSKKR bijection.

Lulek, T.; Lulek, B.; Jakubczyk, P.; Jakubczyk, D.

2006-02-01

156

QCD and String Theory  

E-print Network

This talk begins with some history and basic facts about string theory and its connections with strong interactions. Comparisons of stacks of Dirichlet branes with curved backgrounds produced by them are used to motivate the AdS/CFT correspondence between superconformal gauge theory and string theory on a product of Anti-de Sitter space and a compact manifold. The ensuing duality between semi-classical spinning strings and long gauge theory operators is briefly reviewed. Strongly coupled thermal SYM theory is explored via a black hole in 5-dimensional AdS space, which leads to explicit results for its entropy and shear viscosity. A conjectured universal lower bound on the viscosity to entropy density ratio, and its possible relation to recent results from RHIC, are discussed. Finally, some available results on string duals of confining gauge theories are briefly reviewed.

Igor R. Klebanov

2005-09-09

157

Effect of external electric fields on the phase behavior of colloidal silica rods.  

PubMed

We examine the effect of external electric fields on the behavior of colloidal silica rods. We find that the electric fields can be used to induce para-nematic and para-smectic phases, and to reduce the number of defects in smectic phases. At high field strengths, a new crystal structure was observed that consisted of strings of rods ordered in a hexagonal pattern in which neighboring rods were shifted along their length. We also present a simple model to describe this system, which we used in computer simulations to calculate the phase diagram for rods of L/D = 6, with L the end-to-end length of the rods and D the diameter of the rods. Our theoretical predictions for the phase behavior agree well with the experimental observations. PMID:25017809

Kuijk, Anke; Troppenz, Thomas; Filion, Laura; Imhof, Arnout; van Roij, René; Dijkstra, Marjolein; van Blaaderen, Alfons

2014-09-01

158

Screaming String Thing  

NSDL National Science Digital Library

In this simple and fun activity, learners discover the relationship between vibration and sound by making a squeaky toy instrument out of simple household materials. Participants explore how increasing and decreasing friction on a string changes the sound of a pitch. They also experience how sound is amplified. Learners can expand the activity by linking their string things to create a "telephone" or making different instruments from other recycled materials.

Wgbh

2009-01-01

159

Matrix string theory  

Microsoft Academic Search

Via compactification on a circle, the matrix mode] of M-theory proposed by Banks et a]. suggests a concrete identification between the large N limit of two-dimensional N = 8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the

Robbert Dijkgraaf; Erik Verlinde; Herman L Verlinde

1997-01-01

160

String Theory at LHC Using Top Quarks From String Balls  

E-print Network

According to string theory, string ball is a highly excited long string which decays to standard model particles at the Hagedorn temperature with thermal spectrum. If there are extra dimensions, the string scale can be $\\sim$ TeV, and we should produce string balls at CERN LHC. In this paper we study top quark production from string balls at LHC and compare with the parton fusion results at NNLO using pQCD. We find significant top quark production from string balls at LHC which is comparable to standard model pQCD results. We also find that $\\frac{d\\sigma}{dp_T}$ of top quarks from string balls does not decrease significantly with increase in $p_T$, whereas it deceases sharply in case of standard model pQCD scenario. Hence, in the absence of black hole production at LHC, an enhancement in top quark cross section and its abnormal $p_T$ distribution can be a signature of TeV scale string physics at LHC. String theory is also studied at LHC via string Regge excitations in the weak coupling limit in model independent framework. Since massive quark production amplitude is not available in string Regge excitations scenario, we compute massless quark production in string Regge excitations scenario and make a clear comparison with that produced from string balls at LHC for a given luminosity.

Gouranga C Nayak

2009-02-23

161

String-string duality conjecture in six dimensions and charged solitonic strings  

Microsoft Academic Search

It has recently been conjectured that the type IIA string theory compactified on K3 and the heterotic string theory compactified on a four dimensional torus describe identical string theories. The fundamental heterotic string can be regarded as a non-singular soliton solution of the type IIA string theory with a semi-infinite throat. We show that this solution admits 24 parameter non-singular

Ashoke Sen

1995-01-01

162

Haptic distal spatial perception mediated by strings: haptic "looming".  

PubMed

Five experiments tested a haptic analog of optical looming, demonstrating string-mediated haptic distal spatial perception. Horizontally collinear hooks supported a weighted string held taut by a blindfolded participant's finger midway between the hooks. At the finger, the angle between string segments increased as the finger approached collinearity with the hooks, just as the optical angle subtended by an approaching object increases. The vertical force component at the finger is potentially informative for perception, approaching zero at finger-hook collinearity. In Experiment 1, participants judged hook height reasonably accurately. To retain force relationships but eliminate immediate skin contact, Experiment 2 employed a hand-held rod; results replicated those of Experiment 1. Experiment 3 replicated Experiment 2 using a ring instead of a rod. In all three experiments, estimated hook height closely paralleled actual height, r > .9. Experiments 4 and 5 showed that participants could project impending finger-hook collinearity when finger contact with the string was interrupted during its traverse. Perceivers' estimate errors were nearly perfectly predicted by height-force ratio relationships (Rs > .96). Outcomes are related to optical and acoustic looming, dynamic touch, tau theory, and Gibsonian perceptual theory. PMID:21688938

Cabe, Patrick A

2011-10-01

163

Prevalence and intensity of Capillaria catostomi (Nematoda: Trichuroidea) in white sucker ( Catostomus commersoni ) in southern Lake Huron, Canada  

Microsoft Academic Search

A total of 314 white suckers (Catostomus commersoni) taken monthly during May to December 1975 and in April and May 1976 from southern Lake Huron, Ontario, Canada, were examined forCapillaria catostomi.

David A. Bell; Mary Beverley-Burton

1980-01-01

164

78 FR 22556 - Endangered and Threatened Wildlife and Plants; Revised Recovery Plan for Lost River Sucker and...  

Federal Register 2010, 2011, 2012, 2013

...Information Lost River and shortnose suckers are very similar in ecology. They both predominantly inhabit lake environments but also...populations very vulnerable to drought. Morphological and molecular genetics research indicate that hybridization occurs...

2013-04-16

165

Control rod driveline and grapple  

DOEpatents

A control rod driveline and grapple is disclosed for placement between a control rod drive and a nuclear reactor control rod containing poison for parasitic neutron absorption required for reactor shutdown. The control rod is provided with an enlarged cylindrical handle which terminates in an upwardly extending rod to provide a grapple point for the driveline. The grapple mechanism includes a tension rod which receives the upwardly extending handle and is provided with a lower annular flange. A plurality of preferably six grapple segments surround and grip the control rod handle. Each grapple rod segment grips the flange on the tension rod at an interior upper annular indentation, bears against the enlarged cylindrical handle at an intermediate annulus and captures the upwardly flaring frustum shaped handle at a lower and complementary female segment. The tension rods and grapple segments are surrounded by and encased within a cylinder. The cylinder terminates immediately and outward extending annulus at the lower portion of the grapple segments. Excursion of the tension rod relative to the encasing cylinder causes rod release at the handle by permitting the grapple segments to pivot outwardly and about the annulus on the tension rod so as to open the lower defined frustum shaped annulus and drop the rod. Relative movement between the tension rod and cylinder can occur either due to electromagnetic release of the tension rod within defined limits of travel or differential thermal expansion as between the tension rod and cylinder as where the reactor exceeds design thermal limits.

Germer, John H. (San Jose, CA)

1987-01-01

166

Control rod calibration including the rod coupling effect  

Microsoft Academic Search

In a reactor containing more than one control rod, which includes all reactors licensed in the United States, there will be a 'coupling' or 'shadowing' of control rod flux at the location of a control rod as a result of the flux depression caused by another control rod. It was decided to investigate this phenomenon further, and eventually to put

R. Szilard; G. W. Nelson

1984-01-01

167

The effect of pH on sperm motility of white suckers, Catostomus commersoni , in the Experimental Lakes Area  

Microsoft Academic Search

This study examined the effects of various pH values on sperm motility times of white suckers,Catostomus commersoni, from two artificially acidified lakes in the Experimental Lakes Area (ELA), northwestern Ontario. White sucker sperm were active (motile) in water at all pH values tested (3.0–7.0). The maximum sperm motility time was 76.9 seconds and the minimum time was 51.9 seconds. Sperm

Lloyd C. Mohr; Sandra M. Chalanchuk

1985-01-01

168

Historic and recent age structure and growth of endangered Lost River and shortnose suckers in Upper Klamath Lake, Oregon  

Microsoft Academic Search

Seventy-four lapilli from Lost River suckers captured in Upper Klamath Lake in 1970 during a snag fishery on spawning adults\\u000a and 192 lapilli from adults sacrificed from 2001–2006 were examined to determine age and growth parameters; lapilli from 165\\u000a shortnose suckers sacrificed from Upper Klamath Lake from 2001–2006 were also examined. Relative marginal distance analyses\\u000a indicated that growth marks were

Mark R. Terwilliger; Tamal Reece; Douglas F. Markle

2010-01-01

169

The Birth of String Theory  

NASA Astrophysics Data System (ADS)

Part I. Overview: 1. Introduction and synopsis; 2. Rise and fall of the hadronic string G. Veneziano; 3. Gravity, unification, and the superstring J. H. Schwarz; 4. Early string theory as a challenging case study for philosophers E. Castellani; Part II. The Prehistory: The Analytic S-Matrix: 5. Introduction to Part II; 6. Particle theory in the sixties: from current algebra to the Veneziano amplitude M. Ademollo; 7. The path to the Veneziano model H. R. Rubinstein; 8. Two-component duality and strings P. G. O. Freund; 9. Note on the prehistory of string theory M. Gell-Mann; Part III. The Dual Resonance Model: 10. Introduction to Part III; 11. From the S-matrix to string theory P. Di Vecchia; 12. Reminiscence on the birth of string theory J. A. Shapiro; 13. Personal recollections D. Amati; 14. Early string theory at Fermilab and Rutgers L. Clavelli; 15. Dual amplitudes in higher dimensions: a personal view C. Lovelace; 16. Personal recollections on dual models R. Musto; 17. Remembering the 'supergroup' collaboration F. Nicodemi; 18. The '3-Reggeon vertex' S. Sciuto; Part IV. The String: 19. Introduction to Part IV; 20. From dual models to relativistic strings P. Goddard; 21. The first string theory: personal recollections L. Susskind; 22. The string picture of the Veneziano model H. B. Nielsen; 23. From the S-matrix to string theory Y. Nambu; 24. The analogue model for string amplitudes D. B. Fairlie; 25. Factorization in dual models and functional integration in string theory S. Mandelstam; 26. The hadronic origins of string theory R. C. Brower; Part V. Beyond the Bosonic String: 27. Introduction to Part V; 28. From dual fermion to superstring D. I. Olive; 29. Dual models with fermions: memoirs of an early string theorist P. Ramond; 30. Personal recollections A. Neveu; 31. Aspects of fermionic dual models E. Corrigan; 32. The dual quark models K. Bardakci and M. B. Halpern; 33. Remembering the dawn of relativistic strings J.-L. Gervais; 34. Early string theory in Cambridge: personal recollections C. Montonen; Part VI. The Superstring: 35. Introduction to Part VI; 36. Supersymmetry in string theory F. Gliozzi; 37. Gravity from strings: personal reminiscences of early developments T. Yoneya; 38. From the Nambu-Goto to the ?-model action L. Brink; 39. Locally supersymmetric action for superstring P. Di Vecchia; 40. Personal recollections E. Cremmer; 41. The scientific contributions of Joël Scherk J. H. Schwarz; Part VII. Preparing the String Renaissance: 42. Introduction to Part VII; 43. From strings to superstrings: a personal perspective M. B. Green; 44. Quarks, strings and beyond A. M. Polyakov; 45. The rise of the superstring theory A. Cappelli and F. Colomo; Appendices; Index.

Cappelli, Andrea; Castellani, Elena; Colomo, Filippo; Di Vecchia, Paolo

2012-04-01

170

String Theory: Progress and Problems  

E-print Network

String theory builds on the great legacy of Yukawa and Tomonaga: New degrees of freedom and control of the UV are two important themes. This talk will give an overview of some of the progress and some of the unsolved problems that characterize string theory today. It is divided into two parts: (1) Connecting String Theory to the Real World; (2) Gauge Theory/String Theory Duality. Two other major subjects, which I will omit, are Black Holes in String Theory and The Impact of String Theory on Mathematics.

John H. Schwarz

2007-02-27

171

Analytic progress in open string field theory  

E-print Network

Open string field theory provides an action functional for open string fields, and it is thus a manifestly off-shell formulation of open string theory. The solutions to the equation of motion of open string field theory ...

Kiermaier, Michael Stefan

2009-01-01

172

Biological characteristics of the blue sucker in the James River and the Big Sioux River, South Dakota  

USGS Publications Warehouse

Little is known about the relative abundance and biology of the blue sucker (Cycleptus elongatus), a species that may be declining in some parts of its range. We described the age, growth, condition, length distribution, and habitat preference of the blue sucker in two South Dakota rivers. Specimens were collected from the James River (n=74) and Big Sioux River (n=28) during the summer of 2000. Although five macrohabitats were sampled with electrofishing and hoopnets, most individuals were collected from riffle habitats and downstream of rock dams. Total length-weight relationships were log10W=-6.14+3.37(log10L) (r2 = 0.92) for blue suckers from the James River and log10W = -6.52+3.50(log10L) (r2 = 0.97) for fish from the Big Sioux River. Mean condition factors (K = W(105)/L3) of blue suckers were 0.79 (SE = 0.07) for the James River and 0.73 (SE = 0.07) for the Big Sioux River. Blue suckers between 500 and 700 mm dominated length distributions (range = 374-717 mm) of both samples. Ages ranged from two to nine years, but six-year-old fish were captured most frequently. Blue suckers grew rapidly during juvenile stages (< age 5); however, growth slowed afterward.

Morey, N.M.; Berry, C.R., Jr.

2003-01-01

173

Simulation of nuclear fuel rods by electrically heated rods  

Microsoft Academic Search

For the investigation of thermohydraulic behavior during loss-of-coolant accidents (LOCAs), the nuclear fuel rods are simulated, in out-of-pile experiments, by electrically heated rods. These heater rods are required to produce temperature and heat flux histories at each position of the heater rod surface, identical to those of the nuclear fuel rods. Generally, these requirements are approximated by preprogramming of the

S. Malang; K. Rust

1982-01-01

174

Control rod position indication system  

Microsoft Academic Search

An axial rod position determination system is described for a control rod in a nuclear reactor core, said system comprising: fixed incore detectors; analytical, on-line signature means for periodically creating a response signature database of expected detector response deviations for assumed rod positions from a reference detector response produced at the current rod position by said fixed incore detectors; and

A. J. Jr. Impink; M. D. Heibel; L. R. Grobmyer

1993-01-01

175

Reactor control rod timing system  

Microsoft Academic Search

A fluid driven jet-edge whistle timing system for control rods of a nuclear reactor for producing real-time detection of the timing of each control rod in its scram operation. An important parameter in reactor safety, particularly for liquid metal fast breeder reactors (LMFBR), is the time deviation between the time the control rod is released and the time the rod

Peter T. K

1982-01-01

176

Gravity and Strings  

NASA Astrophysics Data System (ADS)

Preface; Part I. Introduction to Gravity and Supergravity: 1. Differential geometry; 2. Noether's theorems; 3. A perturbative introduction to general relativity; 4. Action principles for gravity; 5. N = 1, 2, d = 4 supergravities; 6. Conserved charges in general relativity; Part II. Gravitating Point-Particles: 7. The Schwarzschild black hole; 8. The Reissner-Nordström black hole; 9. The Taub-NUT solution; 10. Gravitational pp-waves; 11. The Kaluza-Klein black hole; 12. Dilaton and dilaton/axion black holes; 13. Unbroken supersymmetry; Part III. Gravitating Extended Objects of String Theory: 14. String theory; 15. The string effective action and T duality; 16. From eleven to four dimensions; 17. The type-IIB superstring and type-II T duality; 18. Extended objects; 19. The extended objects of string theory; 20. String black holes in four and five dimensions; Appendix A. Lie groups, symmetric spaces and Yang-Mills fields; Appendix B. Gamma matrices and spinors; Appendix C. n-Spheres; Appendix D. Palatini's identity; Appendix E. Conformal rescalings; Appendix F. Connections and curvature components; Appendix G. The harmonic operator on R3 x S1; References; Index.

Ortín, Tomás.

2007-03-01

177

Gravity and Strings  

NASA Astrophysics Data System (ADS)

Preface; Part I. Introduction to Gravity and Supergravity: 1. Differential geometry; 2. Noether's theorems; 3. A perturbative introduction to general relativity; 4. Action principles for gravity; 5. N = 1, 2, d = 4 supergravities; 6. Conserved charges in general relativity; Part II. Gravitating Point-Particles: 7. The Schwarzschild black hole; 8. The Reissner-Nordström black hole; 9. The Taub-NUT solution; 10. Gravitational pp-waves; 11. The Kaluza-Klein black hole; 12. Dilaton and dilaton/axion black holes; 13. Unbroken supersymmetry; Part III. Gravitating Extended Objects of String Theory: 14. String theory; 15. The string effective action and T duality; 16. From eleven to four dimensions; 17. The type-IIB superstring and type-II T duality; 18. Extended objects; 19. The extended objects of string theory; 20. String black holes in four and five dimensions; Appendix A. Lie groups, symmetric spaces and Yang-Mills fields; Appendix B. Gamma matrices and spinors; Appendix C. n-Spheres; Appendix D. Palatini's identity; Appendix E. Conformal rescalings; Appendix F. Connections and curvature components; Appendix G. The harmonic operator on R3 x S1; References; Index.

Ortín, Tomás.

2004-03-01

178

Techniques for Monitoring Razorback Sucker in the Lower Colorado River, Hoover to Parker Dams, 2006-2007, Final Report  

USGS Publications Warehouse

Trammel netting is generally the accepted method of monitoring razorback sucker in reservoirs, but this method is ineffective for monitoring this fish in rivers. Trammel nets set in the current become fouled with debris, and nets set in backwaters capture high numbers of nontarget species. Nontargeted fish composed 97 percent of fish captured in previous studies (1999-2005). In 2005, discovery of a large spawning aggregation of razorback sucker in midchannel near Needles, Calif., prompted the development of more effective methods to monitor this and possibly other riverine fish populations. This study examined the effectiveness of four methods of monitoring razorback sucker in a riverine environment. Hoop netting, electrofishing, boat surveys, and aerial photography were evaluated in terms of data accuracy, costs, stress on targeted fish, and effect on nontargeted fish as compared with trammel netting. Trammel netting in the riverine portion of the Colorado River downstream of Davis Dam, Arizona-Nevada yielded an average of 43 razorback suckers a year (1999 to 2005). Capture rates averaged 0.5 razorback suckers per staff day effort, at a cost exceeding $1,100 per fish. Population estimates calculated for 2003-2005 were 3,570 (95 percent confidence limits [CL] = 1,306i??i??i??-8,925), 1,768 (CL = 878-3,867) and 1,652 (CL = 706-5,164); wide confidence ranges reflect the small sample size. By-catch associated with trammel netting included common carp, game fish and, occasionally, shorebirds, waterfowl, and muskrats. Hoop nets were prone to downstream drift owing to design and anchoring problems aggravated by hydropower ramping. Tests were dropped after the 2006 field season and replaced with electrofishing. Electrofishing at night during low flow and when spawning razorback suckers moved to the shoreline proved extremely effective. In 2006 and 2007, 263 and 299 (respectively) razorback suckers were taken. Capture rates averaged 8.3 razorback suckers per staff day at a cost of $62 per fish. The adult population was estimated at 1,196 (925-1,546) fish. Compared with trammel netting, confidence limits narrowed substantially, from +or- 500 percent to +or- 30 percent, reflecting more precise estimates. By-catch was limited to two common carp. No recreational game fish, waterfowl, or mammals were captured or handled during use of electrofishing. Aerial photography (2006 and 2007) suggested an annual average of 580 fish detected on imagery. Identification of species was not possible; carp commonly have been mistaken for razorback sucker. Field verification determined that the proportion of razorback suckers to other fish was 3:1. On that basis, we estimated 435 razorback suckers were photographed, which equals 8.4 razorback suckers per staff day at a cost of $78 per fish. The data did not lend itself to population estimates. Fish were more easily identified from boats, where their lateral rather than their dorsal aspect is visible. On average, 888 razorback suckers were positively identified each year. Observation rates averaged 29.6 razorback suckers per staff day at a cost less than $18 per fish observed. Sucker densities averaged 20.5 and 9.6 fish/hectare which equated to an average spawning population at Needles, Calif., of 2,520 in 2006 and 1152 in 2007. The lower 2007 estimate reflected a refinement in sampling approach which removed a sampling bias. Electrofishing and boat surveys were more cost effective than other methods tested, and they provided more accurate information without the by-catch associated with trammel netting. However, they provided different types of data. Handling fish may be necessary for research purposes but unnecessary for general trend analysis. Electrofishing was extremely effective but can harm fish if not used with caution. Unnecessary electrofishing increases the likelihood of spinal damage and possible damage to eggs and potential young, and it may alter spawning behavior or duration. B

Mueller, Gordon A.; Wydoski, Richard; Best, Eric; Hiebert, Steve; Lantow, Jeff; Santee, Mark; Goettlicher, Bill; Millosovich, Joe

2008-01-01

179

Ghost Structure and Closed Strings in Vacuum String Field Theory  

Microsoft Academic Search

We complete the construction of vacuum string field theory by proposing a canonical choice of ghost kinetic term -- a local insertion of the ghost field at the string midpoint with an infinite normalization. This choice, supported by level expansion studies in the Siegel gauge, allows a simple analytic treatment of the ghost sector of the string field equations. As

Davide Gaiotto; Leonardo Rastelli; Ashoke Sen; Barton Zwiebach

2001-01-01

180

What is Decidable about Strings?  

E-print Network

We prove several decidability and undecidability results for the satisfiability/validity problem of formulas over a language of finite-length strings and integers (interpreted as lengths of strings). The atomic formulas ...

Ganesh, Vijay

2011-02-01

181

String Theory: Science or Philosophy?  

NSDL National Science Digital Library

This video segment from NOVA discusses the challenge of proving the scientific validity of string theory, in question because strings may be too small to ever be seen or detected, and therefore tested.

Foundation, Wgbh E.

2004-02-20

182

Lattice QCD and String Theory  

E-print Network

Bosonic string formation in gauge theories is reviewed with particular attention to the confining flux in lattice QCD and its string theory description. Recent results on the Casimir energy of the ground state and the string excitation spectrum are analyzed in the Dirichlet string limit of large separation between static sources. The closed string-soliton (torelon) with electric flux winding around a compact dimension and the three-string with a Y-junction created by three static sources are also reviewed. It is shown that string spectra from lattice simulations are consistent with universal predictions of the leading operators from the derivative expansion of a Poincare invariant effective string Lagrangian with reparameterization symmetry. Important characterisitics of the confining flux, like stiffness and the related massive breather modes, are coded in operators with higher derivatives and their determination remains a difficult challenge for lattice gauge theory.

Julius Kuti

2005-11-08

183

On Inflation in String Theory  

E-print Network

In this talk we describe recent progress in construction of inflationary models in the context of string theory with flux compactification and moduli stabilization. We also discuss a possibility to test string theory by cosmological observations.

Renata Kallosh

2007-02-08

184

String radiative backreaction  

SciTech Connect

We discuss radiative backreaction for global strings described by the Kalb-Ramond action with an analogous derivation to that for the point electron in classical electrodynamics. We show how local corrections to the equations of motion allow one to separate the self-field of the string from that of the radiation field. Modifications to this {open_quote}{open_quote}local backreaction approximation{close_quote}{close_quote} circumvent the runaway solutions, allowing these corrections to be used to evolve string trajectories numerically. Comparisons are made with analytic and numerical radiation calculations from previous work and the merits and limitations of this approach are discussed. {copyright} {ital 1995 The American Physical Society.}

Battye, R.A.; Shellard, E.P. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge, CB3 9EW (United Kingdom)] [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge, CB3 9EW (United Kingdom); [Isaac Newton Institute for Mathematical Sciences, Clarkson Road, Cambridge CB3 0EH (United Kingdom)

1995-12-01

185

Mechanisms of acid-base and ionoregulation in white suckers ( Catostomus commersoni ) in natural soft water  

Microsoft Academic Search

Simultaneous measurements of whole body proton flux and both unidirectional and net ion fluxes together with assessment of the blood acid-base, respiratory gas, electrolyte and lactate status were performed in white suckers (Catostomus commersoni) originating from a natural soft water lake ([Ca++]=0.18 meq·l?1) in Ontario, Canada. Fish were examined under control (pH? 6.8) and acidic conditions (pH?4.3) in natural soft

Helve Hõbe; Chris M. Wood; Brian R. McMahon

1984-01-01

186

How do sucker-footed bats hold on, and why do they roost head-up?  

Microsoft Academic Search

Individuals of most bat species hang head-down by their toenails from rough surfaces, but Madagascar's endemic sucker-footed bat (Myzopoda aurita) clings head-up to smooth leaves using specialized pads on its wrists and ankles. We investigated the adhesive performance of 28 individuals and found that attachment performance on brass was not affected by the presence or absence of a seal around

DANIEL K. RISKIN; PAUL A. RACEY

2010-01-01

187

Observations of Age0 Blue Sucker, Cycleptus elongatus Utilizing an Upper Missouri River Backwater  

Microsoft Academic Search

The early life history of blue sucker (Cycleptus elongatus) is relatively unknown across its range; however, we collected seven age-0 specimens in an upper Missouri River backwater in North Dakota during the flood pulses of 1997 and 1999. Specifically, the specimens were captured in the upper 0.4 m of the water column (1.O to 2.5 m total depth) in close

Shannon J. Fisher; David W. Willis

2000-01-01

188

Avoiding paralogy: diploid loci for allotetraploid blue sucker fish ( Cycleptus elongatus , Catostomidae)  

Microsoft Academic Search

The blue sucker (Cycleptus elongatus) is a widespread North American catostomid fish that appears to be declining throughout much of its range. Here, we describe\\u000a the isolation and characterization of eleven microsatellite loci developed for population genetic studies in the genus. We\\u000a show that an additional step of cloning and sequencing can be useful in isolating paralogous loci that often

Michael L. Bessert; Craig Sitzman; Guillermo Ortí

2007-01-01

189

Soil nutrition and temperature as drivers of root suckering in trembling aspen  

Microsoft Academic Search

In two separate studies, the suckering of trembling aspen (Populus tremuloides Michx.) roots was assessed in response to different daily maximum soil temperatures and in relation to available nutrients (CaSO4 and NH4NO3). In the first study, aspen root sections were incubated under high:low temperature regimes of 12:8, 14:8, 16:8, 18:8, or 20:8°C until 124 degree-days above 8°C had been reached.

Erin C. Fraser; Victor J. Lieffers; Simon M. Landhäusser; Brent R. Frey

2002-01-01

190

Age, growth, and maturity of the longnose sucker Catostomus catostomus, of western Lake Superior  

USGS Publications Warehouse

Studies of age, growth, and maturity were based on 1760 fish collected in western Lake Superior in 1964-65. The body:scale relation was curvilinear and the curve had an intercept of 1.65 inches on the length axis. The weight increased as the 2.85 power of the length. Some fish formed an annulus before May 18 in 1965; all had completed annuli by late September. Longnose suckers grew 3.6 inches the 1st year, reached 12 inches in the 6th year, and 18 inches in the 11th year. Fish from Pikes Bay grew faster than those from Gull Island Shoal. Over 6 years were required for weight to reach 1 lb and nearly 10 years to reach 2 lb. Minimum length at maturity was 10.5 inches for males and 11.5 inches for females. The youngest mature male belonged to age-group IV and the youngest mature female to age-group V. All males were mature at 14.5-14.9 inches (age-group VIII) and all females at 15.0-15.4 inches (age-group IX). Finclipped longnose suckers returned to spawn in the Brule River in successive years. One fish returned to spawn in 4 successive years. Many of the fish were not recaptured until 2 or 3 years after marking. The time of the Brule River spawning migration depended more on water temperature than on length of day. The average water temperature during the peak of the spawning runs of 1958-64 was 55.4 F. Larval suckers apparently spend little time in the Brule River and adjacent streams and drift downstream to the lake soon after hatching. The number of eggs in the ovaries of eight suckers ranged from 14 to 35 thousand and averaged 24 thousand for fish 13.9-17.7 inches long.

Bailey, Merryll M.

1969-01-01

191

Cosmic strings and galaxy formation  

NASA Technical Reports Server (NTRS)

The cosmogonical model proposed by Zel'dovich and Vilenkin (1981), in which superconducting cosmic strings act as seeds for the origin of structure in the universe, is discussed, summarizing the results of recent theoretical investigations. Consideration is given to the formation of cosmic strings, the microscopic structure of strings, gravitational effects, cosmic string evolution, and the formation of galaxies and large-scale structure. Simulation results are presented in graphs, and several outstanding issues are listed and briefly characterized.

Bertschinger, Edmund

1989-01-01

192

Renormalization aspects of chaotic strings  

NASA Astrophysics Data System (ADS)

Chaotic strings are a class of non-hyperbolic coupled map lattices, exhibiting a rich structure of complex dynamical phenomena with a surprising correspondence to physical contents. In this paper we introduce different types and models for chaotic strings, where 2B-strings with finite length are considered in detail. We demonstrate possibilities to extract renormalized quantities, which are expected to describe essential properties of the string.

Groote, S.; Veermäe, H.; Beck, C.

2014-09-01

193

Dilatonic, Chiral Cosmic Strings  

E-print Network

In this work, we deal with the chiral string model for which the world-sheet current is null in the framework of a scalar-tensor gravity. Our main goal is to analyse the impact of such a current on the gravitational macroscopic effects. For the purpose of this analysis, we first study the gravitational properties of the spacetime generated by this string in the presence of a dilaton field. Then, we carry out an investigation of the mechanism of formation and evolution of wakes in this framework, showing the explicit contribution of the chirality to this effect.

V. C. Andrade; A. L. Naves de Oliveira; M. E. X. Guimarães

2004-11-25

194

Probing the String Landscape  

ScienceCinema

We are currently in the throes of a potentially huge paradigm shift in physics. Motivated by recent developments in string theory and the discovery of the so-called "string landscape", physicists are beginning to question the uniqueness of fundamental theories of physics and the methods by which such theories might be understood and investigated. In this colloquium, I will give a non-technical introduction to the nature of this paradigm shift and how it developed. I will also discuss some of the questions to which it has led, and the nature of the controversies it has spawned.

Keith Dienes

2010-01-08

195

Twisted Skyrmion String  

E-print Network

We study nonlinear sigma model, especially Skyrme model without twist and Skyrme model with twist: twisted Skyrmion string. Twist term, $mkz$, is indicated in vortex solution. Necessary condition for stability of vortex solution has consequence that energy of vortex is minimum and scale-free (vortex solution is neutrally stable to changes in scale). We find numerically that the value of vortex minimum energy per unit length for twisted Skyrmion string is $20.37\\times 10^{60}~\\text{eV/m}$.

Miftachul Hadi; Malcolm Anderson; Andri Husein

2014-04-30

196

String Theory and Turbulence  

E-print Network

We propose a string theory of turbulence that explains the Kolmogorov scaling in 3+1 dimensions and the Kraichnan and Kolmogorov scalings in 2+1 dimensions. This string theory of turbulence should be understood in light of the AdS/CFT dictionary. Our argument is crucially based on the use of Migdal's loop variables and the self-consistent solutions of Migdal's loop equations for turbulence. In particular, there is an area law for turbulence in 2+1 dimensions related to the Kraichnan scaling.

Vishnu Jejjala; Djordje Minic; Y. Jack Ng; Chia-Hsiung Tze

2009-12-14

197

Probing the String Landscape  

SciTech Connect

We are currently in the throes of a potentially huge paradigm shift in physics. Motivated by recent developments in string theory and the discovery of the so-called "string landscape", physicists are beginning to question the uniqueness of fundamental theories of physics and the methods by which such theories might be understood and investigated. In this colloquium, I will give a non-technical introduction to the nature of this paradigm shift and how it developed. I will also discuss some of the questions to which it has led, and the nature of the controversies it has spawned.

Keith Dienes

2009-12-01

198

Rod Contributions to Color Perception: Linear with Rod Contrast  

PubMed Central

At mesopic light levels, an incremental change in rod activation causes changes in color appearance. In this study, we investigated how rod mediated changes in color perception varied as a function of the magnitude of the rod contrast. Rod-mediated changes in color appearance were assessed by matching them with cone-mediated color changes. A two-channel four-primary colorimeter allowed independent control of the rods and each of the L-, M- and S-cone photoreceptor types. At all light levels, rod contributions to inferred PC, KC and MC pathway mediated vision were linearly related to the rod incremental contrast. This linear relationship could be described by a model based on primate ganglion cell responses with the assumption that rod signals were conveyed via rod-cone gap junctions at mesopic light levels. PMID:18561973

Cao, Dingcai; Pokorny, Joel; Smith, Vivianne C.; Zele, Andrew J.

2008-01-01

199

Flannelmouth suckers: Movement in the Glen Canyon reach and spawning in the Paria River  

NASA Astrophysics Data System (ADS)

Flannelmouth sucker (Catostomus latipinnis) spawn March through April in the Paria River, a tributary of the Colorado River 25 km downstream of Glen Canyon Dam. We followed 50 ultrasonic-tagged, adult flannelmouth suckers in the Glen Canyon reach to determine if this native species was displaced downstream by the controlled flood. We also seined and made visual observations over known spawning areas in the Paria River during the flood, and surveyed for presence of young-of-the-year (YOY) during the summer rearing season to determine if the flood preempted or delayed spawning. Conservatively, forty-two (84%) tagged fish stayed within the Glen Canyon reach; the majority (33) used a low-velocity ponded habitat formed when high Colorado River flows ponded the lower 0.76 km of the Paria River. Spawning in the Paria River during 1996 was successful as evidenced by the presence of ripe fish over known spawning areas and by capture of a strong year-class of YOY in late spring and summer. Thus, we found no obvious deleterious effects of the controlled flood on movement of flannelmouth sucker in the Glen Canyon reach or on spawning in the Paria River.

McIvor, Carole C.; Thieme, Michele L.

200

Correlation of gene expression and contaminant concentrations in wild largescale suckers: a field-based study.  

PubMed

Toxic compounds such as organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ether flame retardants (PBDEs) have been detected in fish, birds, and aquatic mammals that live in the Columbia River or use food resources from within the river. We developed a custom microarray for largescale suckers (Catostomus macrocheilus) and used it to investigate the molecular effects of contaminant exposure on wild fish in the Columbia River. Using Significance Analysis of Microarrays (SAM) we identified 72 probes representing 69 unique genes with expression patterns that correlated with hepatic tissue levels of OCs, PCBs, or PBDEs. These genes were involved in many biological processes previously shown to respond to contaminant exposure, including drug and lipid metabolism, apoptosis, cellular transport, oxidative stress, and cellular chaperone function. The relation between gene expression and contaminant concentration suggests that these genes may respond to environmental contaminant exposure and are promising candidates for further field and laboratory studies to develop biomarkers for monitoring exposure of wild fish to contaminant mixtures found in the Columbia River Basin. The array developed in this study could also be a useful tool for studies involving endangered sucker species and other sucker species used in contaminant research. PMID:24050789

Christiansen, Helena E; Mehinto, Alvine C; Yu, Fahong; Perry, Russell W; Denslow, Nancy D; Maule, Alec G; Mesa, Matthew G

2014-06-15

201

Correlation of gene expression and contaminat concentrations in wild largescale suckers: a field-based study  

USGS Publications Warehouse

Toxic compounds such as organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ether flame retardants (PBDEs) have been detected in fish, birds, and aquatic mammals that live in the Columbia River or use food resources from within the river. We developed a custom microarray for largescale suckers (Catostomus macrocheilus) and used it to investigate the molecular effects of contaminant exposure on wild fish in the Columbia River. Using Significance Analysis of Microarrays (SAM) we identified 72 probes representing 69 unique genes with expression patterns that correlated with hepatic tissue levels of OCs, PCBs, or PBDEs. These genes were involved in many biological processes previously shown to respond to contaminant exposure, including drug and lipid metabolism, apoptosis, cellular transport, oxidative stress, and cellular chaperone function. The relation between gene expression and contaminant concentration suggests that these genes may respond to environmental contaminant exposure and are promising candidates for further field and laboratory studies to develop biomarkers for monitoring exposure of wild fish to contaminant mixtures found in the Columbia River Basin. The array developed in this study could also be a useful tool for studies involving endangered sucker species and other sucker species used in contaminant research.

Christiansen, Helena E.; Mehinto, Alvina C.; Yu, Fahong; Perry, Russell W.; Denslow, Nancy D.; Maule, Alec G.; Mesa, Matthew G.

2014-01-01

202

String Theory and Gauge Theories  

SciTech Connect

We will see how gauge theories, in the limit that the number of colors is large, give string theories. We will discuss some examples of particular gauge theories where the corresponding string theory is known precisely, starting with the case of the maximally supersymmetric theory in four dimensions which corresponds to ten dimensional string theory. We will discuss recent developments in this area.

Juan Maldacena

2009-02-20

203

STRING THEORY Problem Set # 5  

E-print Network

STRING THEORY Problem Set # 5 February 20, 1997 Problem 1 In this problem, we determine the dilaton the dilaton. Problem 2 In this problem, we perform a number of calculations in closed oriented string theory, we perform a number of calculations in open oriented string theory, in flat space

204

New Connections Between String Theories  

Microsoft Academic Search

We consider the R-->0 limit of toroidal compactification in various string theories. This leads to new connections between seemingly different string theories: IIA and IIB, open and closed, oriented and unoriented. We also find two new extended objects which can couple consistently to strings: the Dirichlet-brane and the orientifold plane.

Jin Dai; R. G. Leigh; Joseph Polchinski

1989-01-01

205

Beyond relativistic quantum string theory  

NASA Astrophysics Data System (ADS)

The question "What lies beyond the Quantized String or Superstring Theory?" and the question "What lies beyond Quantum Mechanics itself?" might have one common answer: a discretized, classical version of string theory, which lives on a lattice in Minkowski space. The size a of the meshes on this lattice in Minkowski space is determined by the string slope parameter, ??.

't Hooft, Gerard

2014-08-01

206

String theory and quark confinement  

Microsoft Academic Search

This article is based on a talk given at the “Strings '97” conference. It discusses the search for the universality class of confining strings. The key ingredients include the loop equations, the zigzag symmetry, the non-linear renormalization group. Some new tests for the equivalence between gauge fields and strings are proposed.

Alexandre M. Polyakov

1998-01-01

207

Dynamical String Tension in String Theory with Spacetime Weyl Invariance  

E-print Network

The fundamental string length, which is an essential part of string theory, explicitly breaks scale invariance. However, in field theory we demonstrated recently that the gravitational constant, which is directly related to the string length, can be promoted to a dynamical field if the standard model coupled to gravity (SM+GR) is lifted to a locally scale (Weyl) invariant theory. The higher gauge symmetry reveals previously unknown field patches whose inclusion turn the classically conformally invariant SM+GR into a geodesically complete theory with new cosmological and possibly further physical consequences. In this paper this concept is extended to string theory by showing how it can be Weyl lifted with a local scale symmetry acting on target space background fields. In this process the string tension (fundamental string length) is promoted to a dynamical field, in agreement with the parallel developments in field theory. We then propose a string theory in a geodesically complete cosmological stringy backgr...

Bars, Itzhak; Turok, Neil

2014-01-01

208

Thermocouple based control rod position indication system  

SciTech Connect

This patent describes a rod position determination method. It comprises: measuring core coolant inlet temperature; measuring core coolant assembly exit temperature associated with a control rod; determining enthalpy rise from the inlet and exit temperature and a reference for an assembly containing the rod; determining the rod position charge; and determining the rod position from the rod position change and a reference rod position.

Heibel, M.D.; Impink, A.J. Jr.; Grobmyer, L.R.

1990-05-22

209

Exotic nonrelativistic string  

SciTech Connect

We construct a classical nonrelativistic string model in 3+1 dimensions. The model contains a spurion tensor field that is responsible for the noncommutative structure of the model. Under double-dimensional reduction the model reduces to the exotic nonrelativistic particle in 2+1 dimensions.

Casalbuoni, Roberto; Gomis, Joaquim; Longhi, Giorgio [Department of Physics, University of Florence, INFN, Florence (Italy) and Galileo Galilei Institute for Theoretical Physics, Florence (Italy); PH-TH Division, CERN, CH -1211 Geneva 23 (Switzerland) and Departament d'Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Department of Physics, University of Florence and INFN, Florence (Italy)

2007-12-15

210

Cosmic string loop microlensing  

NASA Astrophysics Data System (ADS)

Cosmic superstring loops within the galaxy microlens background point sources lying close to the observer-string line of sight. For suitable alignments, multiple paths coexist and the (achromatic) flux enhancement is a factor of two. We explore this unique type of lensing by numerically solving for geodesics that extend from source to observer as they pass near an oscillating string. We characterize the duration of the flux doubling and the scale of the image splitting. We probe and confirm the existence of a variety of fundamental effects predicted from previous analyses of the static infinite straight string: the deficit angle, the Kaiser-Stebbins effect, and the scale of the impact parameter required to produce microlensing. Our quantitative results for dynamical loops vary by O(1) factors with respect to estimates based on infinite straight strings for a given impact parameter. A number of new features are identified in the computed microlensing solutions. Our results suggest that optical microlensing can offer a new and potentially powerful methodology for searches for superstring loop relics of the inflationary era.

Bloomfield, Jolyon K.; Chernoff, David F.

2014-06-01

211

Wing on a String  

ERIC Educational Resources Information Center

In this article, the authors present an activity that shows students how flight occurs. The "wing on a string" is a simple teacher-made frame that consists of PVC pipe, fishing line, and rubber bands--all readily available hardware store items. The only other materials/tools involved are a sheet of paper, some pieces of a soda straw, a stapler,…

Fitzgerald, Mike; Brand, Lance

2004-01-01

212

Music: Instrumental Techniques, Strings.  

ERIC Educational Resources Information Center

A course in music which emphasizes harmony is presented. The approach used is a laboratory one in which pupils will develop skill in playing orchestral string instruments, sing, listen to, read and compose music with emphasis on elementary concepts of harmony. Course objectives include: (1) The student will select the title of a familiar melody…

Ryan, Philip

213

Inflation, String Theory and Cosmology  

E-print Network

At its very beginning, the universe is believed to have grown exponentially in size via the mechanism of inflation. The almost scale-invariant density perturbation spectrum predicted by inflation is strongly supported by cosmological observations, in particular the cosmic microwave background radiation. However, the universe's precise inflationary scenario remains a profound problem for cosmology and for fundamental physics. String theory, the most-studied theory as the final physical theory of nature, should provide an answer to this question. Some of the proposals on how inflation is realized in string theory are reviewed. Since everything is made of strings, some string loops of cosmological sizes are likely to survive in the hot big bang that followed inflation. They appear as cosmic strings, which can have intricate properties. Because of the warped geometry in flux compactification of the extra spatial dimensions in string theory, some of the cosmic strings may have tensions substantially below the Plan...

Chernoff, David F

2014-01-01

214

Population biology and host-parasite relationships of Triganodistomum attenuatum (Trematoda: Lissorchiidae) infecting the white sucker, Catostomus commersoni (Lacépède).  

PubMed

Triganodistomum attenuatum demonstrated similar seasonal infection patterns in white suckers, Catostomus commersoni, from the Bellamy and Oyster rivers, New Hampshire. Mean intensity was highest in spring 1975 and 1976. Nongravid and gravid worms were common in the spring, and in the spring and summer, respectively. Most individuals of T. attenuatum parasitized the posterior portion of the sucker's intestine. No definite changes in prevalence and mean intensity were evident at either river as fish size increased. Male and female suckers had similar prevalences and mean intensities of infections. Although a significantly larger number of suckers from the Oyster River was infected than from the Bellamy River, the mean intensities were similar. Triganodistomum attenuatum was found to be host specific to the white sucker. Other fish species examined for the presence of T. attenuatum were as follow: creek chubsucker (Erimyzon oblongus), fallfish (Semotilus corporalis), golden shiner (Notemigonus crysoleucas), bridle shiner (Notropis bifrenatus), common shiner (N. cornutus), longnose dace (Rhinichthys cataractae), redfin pickerel (Esox americanus), pumpkinseed (Lepomis gibbosus), and swamp darter (Etheostoma fusiforme). The state of New Hampshire is a new locality record for T. attenuatum. PMID:7391871

Muzzall, P M

1980-04-01

215

Control rod inspection experience  

Microsoft Academic Search

Full text: The Technical Specifications of the Kansas State University TRIGA Mk II Nuclear Reactor require, among other things, that the control rods be 'visually inspected' every two years for indication of significant distortion or deterioration. The 'visual inspection' presently consists of close-up photography of the poison section, measurement of the diameter of the cladding with a vernier caliper, weighing

McEwan; Michael J

1978-01-01

216

Control rod studies  

Microsoft Academic Search

This study was undertaken to answer questions asked regarding the required rod stroke for control of modified Tory II-C reactors. All problems described were solved with the Angie code and based on Tory-II-C design problems, RZ 501 and RZ 502, representing hot and cold reactors respectively.

1963-01-01

217

Concentrations of Cadmium, Cobalt, Lead, Nickel, and Zinc in Blood and Fillets of Northern Hog Sucker ( Hypentelium nigricans ) from Streams Contaminated by Lead–Zinc Mining: Implications for Monitoring  

Microsoft Academic Search

Lead (Pb) and other metals can accumulate in northern hog sucker (Hypentelium nigricans) and other suckers (Catostomidae), which are harvested in large numbers from Ozark streams by recreational fishers. Suckers\\u000a are also important in the diets of piscivorous wildlife and fishes. Suckers from streams contaminated by historic Pb–zinc\\u000a (Zn) mining in southeastern Missouri are presently identified in a consumption advisory

C. J. Schmitt; W. G. Brumbaugh; T. W. May

2009-01-01

218

Postmodern string theory stochastic formulation  

E-print Network

In this paper we study the dynamics of a statistical ensemble of strings, building on a recently proposed gauge theory of the string geodesic field. We show that this stochastic approach is equivalent to the Carath\\'eodory formulation of the Nambu-Goto action, supplemented by an averaging procedure over the family of classical string world-sheets which are solutions of the equation of motion. In this new framework, the string geodesic field is reinterpreted as the Gibbs current density associated with the string statistical ensemble. Next, we show that the classical field equations derived from the string gauge action, can be obtained as the semi-classical limit of the string functional wave equation. For closed strings, the wave equation itself is completely analogous to the Wheeler-DeWitt equation used in quantum cosmology. Thus, in the string case, the wave function has support on the space of all possible spatial loop configurations. Finally, we show that the string distribution induces a multi-phase, or ...

Aurilia, A

1994-01-01

219

Postmodern String Theory: Stochastic Formulation  

E-print Network

In this paper we study the dynamics of a statistical ensemble of strings, building on a recently proposed gauge theory of the string geodesic field. We show that this stochastic approach is equivalent to the Carath\\'eodory formulation of the Nambu-Goto action, supplemented by an averaging procedure over the family of classical string world-sheets which are solutions of the equation of motion. In this new framework, the string geodesic field is reinterpreted as the Gibbs current density associated with the string statistical ensemble. Next, we show that the classical field equations derived from the string gauge action, can be obtained as the semi-classical limit of the string functional wave equation. For closed strings, the wave equation itself is completely analogous to the Wheeler-DeWitt equation used in quantum cosmology. Thus, in the string case, the wave function has support on the space of all possible spatial loop configurations. Finally, we show that the string distribution induces a multi-phase, or {\\it cellular} structure on the spacetime manifold characterized by domains with a purely Riemannian geometry separated by domain walls over which there exists a predominantly Weyl geometry.

A. Aurilia; E. Spallucci; I. Vanzetta

1994-08-16

220

The relationship between piscivory and growth of white sucker ( Catostomus commersoni ) and yellow perch ( Perca flavescens ) in headwater lakes of the Canadian Shield  

Microsoft Academic Search

We used data from a survey of 36 headwater lakes of the Canadian Shield to investigate the relationship between piscivory and growth, abundance, and longevity of white sucker (Catostomus commersoni) and yellow perch (Perca flavescens). The occurrence of northern pike (Esox lucius) and walleye (Sander vitreus) explained variations in the abundance of both white sucker and yellow perch, suggesting strong

Andrea Bertolo; Pierre Magnan

2005-01-01

221

Corpuscles of Stannius and stanniocalcin-like immunoreactivity in the white sucker ( Catostomus commersoni ): evidence for a new cell-type  

Microsoft Academic Search

The distribution of stanniocalcin immunoreactivity was examined in the corpuscles of Stannius of the white sucker (Catostomus commersoni) by using a chum salmon stanniocalcin antiserum, Western blotting, and light and electron microscopy. The white sucker possesses at least two stanniocalcin-immunoreactive corpuscles in the most posterior portions of the kidneys. Immunocytochemistry and ultrastructure revealed two cell-types in the corpuscle parenchyma, only

L. E. Marra; D. G. Butler; D. H. Zhang; G. Y. Oudit; J. H. Youson

1998-01-01

222

Spatial and temporal variation in abundance of Diplostomum spp. in walleye ( Stizostedion vitreum ) and white suckers ( Catostomus commersoni ) from the St. Lawrence River  

Microsoft Academic Search

Abundances of eye flukes (Diplostomum spp.) were compared between walleye (Stizostedion vitreum) and white suckers (Catostomus commersoni ) collected in late summer 1997 from Lake St. Louis and Lake St. Pierre, two expansions of the St. Lawrence River in Quebec, Canada. The white sucker, a benthic consumer, was more heavily in- fected than the walleye, a pelagic piscivore, in both

David J. Marcogliese; Pierre Dumont; Andrée D. Gendron; Yves Mailhot; Emmanuelle Bergeron; J. Daniel McLaughlin

2001-01-01

223

Rapid Out-Migration of Lost River and Shortnose Sucker Larvae from In-River Spawning Beds to In-Lake Rearing Grounds  

Microsoft Academic Search

We examined the process of larval out-migration of endangered Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris from spawning grounds in the Williamson and Sprague rivers to rearing grounds in Upper Klamath Lake. Most downstream movement occurred at night, when larvae drifted in surface currents at the center of the channel. During daylight, larvae were absent from the

Michael Cooperman; Douglas F. Markle

2003-01-01

224

CONTROL RODS FOR NUCLEAR REACTORS  

Microsoft Academic Search

A means for controlling the control rod in emergency, when it is desired ; to shutdown the reactor with the shortest possible delay, is described. When the ; emergency occurs the control rod is allowed to drop freely under gravity from the ; control rod support tube into the bore in the reactor core. A normal shutdown is ; reached

Bell

1963-01-01

225

Hydraulic drive for control rods  

Microsoft Academic Search

A nuclear reactor is disclosed wherein hydraulic drive mechanisms for control rods are provided with a positive mechanical latching arrangement to maintain the control rods in a withdrawn position with respect to the core. With this arrangement, the coil of an associated electromagnet must be deliberately energized in order to insert the control rod into the core thus making accidental

E. Frisch; H. N. Andrews

1976-01-01

226

Anyons from Strings  

SciTech Connect

The Nambu-Goto string in a three-dimensional (3D) Minkowski spacetime is quantized preserving Lorentz invariance and parity. The spectrum of massive states contains anyons. An ambiguity in the ground state energy is resolved by the 3D N=1 Green-Schwarz superstring, which has massless ground states describing a dilaton and dilatino, and first-excited states of spin 1/4.

Mezincescu, Luca [Department of Physics, University of Miami, Coral Gables, Florida 33124 (United States); Townsend, Paul K. [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

2010-11-05

227

Twistor strings with flavour  

Microsoft Academic Search

We explore the tree-level description of a class of Script N = 2 UV-finite SYM theories with fundamental flavour within a topological B-model twistor string framework. In particular, we identify the twistor dual of the Sp(N) gauge theory with one antisymmetric and four fundamental hypermultiplets, as well as that of the SU(N) theory with 2N hypermultiplets. This is achieved by

James Bedford; Constantinos Papageorgakis; Konstantinos Zoubos

2007-01-01

228

A Warped Cosmic String  

SciTech Connect

We present a cosmic string solution in Einstein-Yang-Mills Gauss-Bonnet theory on a warped 5 dimensional space-time conform the Randall-Sundrum-2 theory. In a simplipied model, we find an exact solutions with exponential decreasing or periodic warp function. In a more general setting, where the metric- and Yang-Mills components depend on both scales and one of the YM components resides in the bulk, we find a time dependent numerical solution.

Slagter, R. J. [Institute of Physics, University of Amsterdam and ASFYON, Astronomisch Fysisch Onderzoek Nederland, 1405EP Bussum (Netherlands)

2010-06-23

229

Swinging on a String  

NSDL National Science Digital Library

Students explore how pendulums work and why they are useful in everyday applications. In a hands-on activity, they experiment with string length, pendulum weight and angle of release. In an associated literacy activity, students explore the mechanical concept of rhythm, based on the principle of oscillation, in a broader biological and cultural context â in dance and sports, poetry and other literary forms, and communication in general.

Integrated Teaching And Learning Program

230

From fields to strings  

NASA Astrophysics Data System (ADS)

The quest for unification / G. G. Ross -- Chaos, symmetry and string cosmology / T. Damour -- Extra dimensions and branes / C. Csáki -- Looking at the cosmological constant from infinite-volume bulk -- New old inflation -- Conformal fixed points of unidentified gauge theories / A. M. Polyakov -- SL(2, Z) action on three-dimensional conformal field theories with Abelian symmetry / E. Witten -- Logarithmic conformal field theory or how to compute a torus amplitude on the sphere / M. Flohr -- Logarithmic conformal field theories and strings in changing backgrounds / N. E. Mavromatos -- Finite density states in integrable conformal field theories / N. Mann and J. Polchinski -- Conformal field theory at central charge c = 0 and two-dimensional critical systems with quenched disorder / V. Gurarie and A. W. W. Ludwig -- Boundary states and broken bulk symmetries in WA[symbol] minimal models / A. F. Caldeira and J. F. Wheater -- Lectures on AdS/CFT / J. M. Maldacena -- The search for a holographic dual to AdS[symbol] x S[symbol] x S[symbol] x S[symbol] / S. Gukov ... [et al.] -- Chern-Simons gauge theory and the AdS[symbol]/CFT[symbol] correspondence / S. Gukov ... [et al.] -- Spinning strings and AdS/CFT duality / A. A. Tseytlin -- R-symmetries, algebraic geometry, and AdS/CFT / A. Ritz.

Shifman, Misha; Vainshtein, Arkady; Wheater, J. F.

231

Logic and String Theory  

E-print Network

The unification of Quantum Mechanics and General Relativity remains the primary goal of Theoretical Physics, with string theory appearing as the only plausible unifying scheme. In the present work, in a search of the conceptual foundations of string theory, we analyze the relational logic developed by C. S. Peirce in the late nineteenth century. The Peircean logic has the mathematical structure of a category with the relation $R_{ij}$ among two individual terms $S_i$ and $S_j$, serving as an arrow (or morphism). We introduce a realization of the corresponding categorical algebra of compositions, which naturally gives rise to the fundamental quantum laws, thus underscoring the relational character of Quantum Mechanic. The same relational algebra generates a number of group structures, among them $W_{\\infty}$. The group $W_{\\infty}$ is embodied and realized by the matrix models, themselves closely linked with string theory. It is suggested that relational logic and in general category theory may provide a new paradigm, within which to develop modern physical theories.

A. Nicolaidis

2008-04-18

232

Relationship of length of fish to incidence of sea lamprey scars on white suckers, Catostomus commersoni, in Lake Huron  

USGS Publications Warehouse

During the course of experimental fishing operations conducted by the staff of Hammond Bay Fishery Laboratory (a field station of Great Lakes Fishery Investigations) in 1950-1951, length measurements and records of scarring incidence and number of scars per individual were obtained for a sample of 552 white suckers, Catostomus commersoni (Lacepede). The results of this study indicate that if information on the incidence of sea lamprey scars on white suckers is to be used to judge the relative abundance of sea lampreys and the damages inflicted by that parasite on the sucker stock, data must include records of the lengths of fish. It is to be suspected strongly that a similar conclusion applies in other localities and to other species preyed upon by the sea lamprey.

Hall, A.E.; Elliott, Oliver R.

1954-01-01

233

String Calculus: Conformal Field Theory as a Tool in String Theory  

E-print Network

String Calculus: Conformal Field Theory as a Tool in String Theory Emil Martinec Enrico Fermi Inst, in the guise of string theory. String theory promises an elegant synthesis of quan- tum mechanics (algebra in string theory in the description of perturbative string propagation. However, one might believe

Gardel, Margaret

234

String fluid in local equilibrium  

NASA Astrophysics Data System (ADS)

We study the solutions of string fluid equations under the assumption of a local equilibrium which was previously obtained in the context of the kinetic theory. We show that the fluid can be foliated into noninteracting submanifolds whose equations of motion are exactly that of the wiggly strings considered previously by Vilenkin and Carter. In a special case of negligible statistical variance in either the left- or the right-moving directions of microscopic strings, the submanifolds are described by the action of a null-current-carrying chiral string. When both variances vanish the submanifolds are described by the Nambu-Goto action and the string fluid reduces to the string dust introduced by Stachel.

Schubring, Daniel; Vanchurin, Vitaly

2014-10-01

235

Self-recognition mechanism between skin and suckers prevents octopus arms from interfering with each other.  

PubMed

Controlling movements of flexible arms is a challenging task for the octopus because of the virtually infinite number of degrees of freedom (DOFs) [1, 2]. Octopuses simplify this control by using stereotypical motion patterns that reduce the DOFs, in the control space, to a workable few [2]. These movements are triggered by the brain and are generated by motor programs embedded in the peripheral neuromuscular system of the arm [3-5]. The hundreds of suckers along each arm have a tendency to stick to almost any object they contact [6-9]. The existence of this reflex could pose significant problems with unplanned interactions between the arms if not appropriately managed. This problem is likely to be accentuated because it is accepted that octopuses are "not aware of their arms" [10-14]. Here we report of a self-recognition mechanism that has a novel role in motor control, restraining the arms from interfering with each other. We show that the suckers of amputated arms never attach to octopus skin because a chemical in the skin inhibits the attachment reflex of the suckers. The peripheral mechanism appears to be overridden by central control because, in contrast to amputated arms, behaving octopuses sometime grab amputated arms. Surprisingly, octopuses seem to identify their own amputated arms, as they treat arms of other octopuses like food more often than their own. This self-recognition mechanism is a novel peripheral component in the embodied organization of the adaptive interactions between the octopus's brain, body, and environment [15, 16]. PMID:24835454

Nesher, Nir; Levy, Guy; Grasso, Frank W; Hochner, Binyamin

2014-06-01

236

Experimenting with string musical instruments  

NASA Astrophysics Data System (ADS)

What follows are several investigations involving string musical instruments developed for and used in a Science of Sound & Light course. The experiments make use of a guitar, orchestral string instruments and data collection and graphing software. They are designed to provide students with concrete examples of how mathematical formulae, when used in physics, represent reality that can actually be observed, in this case, the operation of string musical instruments.

LoPresto, Michael C.

2012-03-01

237

Classical theory of radiating strings  

NASA Technical Reports Server (NTRS)

The divergent part of the self force of a radiating string coupled to gravity, an antisymmetric tensor and a dilaton in four dimensions are calculated to first order in classical perturbation theory. While this divergence can be absorbed into a renormalization of the string tension, demanding that both it and the divergence in the energy momentum tensor vanish forces the string to have the couplings of compactified N = 1 D = 10 supergravity. In effect, supersymmetry cures the classical infinities.

Copeland, Edmund J.; Haws, D.; Hindmarsh, M.

1990-01-01

238

Rod swap analysis using SIMULATE3  

Microsoft Academic Search

The rod swap method is often used to measure control rod worths during low-power physics testing for pressurized water reactors (PWRs). Rod swap can be more advantageous than the conventional control rod measurement technique of boration\\/dilution because it is less time consuming. Rod swap calculations, however, present a more difficult challenge to the core analysis engineer. Predictions of rod swap

A. S. DiGiovine; L. P. Elizondo

1989-01-01

239

Thermocouple based control rod position indication system  

Microsoft Academic Search

This patent describes a rod position determination method. It comprises: measuring core coolant inlet temperature; measuring core coolant assembly exit temperature associated with a control rod; determining enthalpy rise from the inlet and exit temperature and a reference for an assembly containing the rod; determining the rod position charge; and determining the rod position from the rod position change and

M. D. Heibel; A. J. Jr. Impink; L. R. Grobmyer

1990-01-01

240

Maximum\\/minimum asymmetric rod detection  

Microsoft Academic Search

This patent describes a system for determining the relative position of each control rod within a control rod group in a nuclear reactor. The control rod group having at least three control rods therein. It comprises: means for producing a signal representative of a position of each control rod within the control rod group in the nuclear reactor; means for

1990-01-01

241

Chiral cosmic strings in supergravity  

E-print Network

We consider F and D-term cosmic strings formed in supersymmetric theories. Supersymmetry is broken inside the string core, but restored outside. In global SUSY, this implies the existence of goldstino zero modes, and the string potentially carries fermionic currents. We show that these zero modes do not survive the coupling to gravity, due to the super Higgs mechanism. Therefore the superconductivity and chirality properties are different in global and local supersymmetry. For example, a string formed at the end of D-term inflation is chiral in supergravity but non-chiral in global SUSY.

Rachel Jeannerot; Marieke Postma

2004-11-19

242

Evolution of cosmic string networks  

NASA Technical Reports Server (NTRS)

Results on cosmic strings are summarized including: (1) the application of non-equilibrium statistical mechanics to cosmic string evolution; (2) a simple one scale model for the long strings which has a great deal of predictive power; (3) results from large scale numerical simulations; and (4) a discussion of the observational consequences of our results. An upper bound on G mu of approximately 10(-7) emerges from the millisecond pulsar gravity wave bound. How numerical uncertainties affect this are discussed. Any changes which weaken the bound would probably also give the long strings the dominant role in producing observational consequences.

Albrecht, Andreas; Turok, Neil

1989-01-01

243

Supersymmetric heterotic string backgrounds  

E-print Network

We present the main features of the solution of the gravitino and dilatino Killing spinor equations derived in hep-th/0510176 and hep-th/0703143 which have led to the classification of geometric types of all type I backgrounds. We then apply these results to the supersymmetric backgrounds of the heterotic string. In particular, we solve the gaugino Killing spinor equation together with the other two Killing spinor equations of the theory. We also use our results to classify all supersymmetry conditions of ten-dimensional gauge theory.

Ulf Gran; George Papadopoulos; Diederik Roest

2007-06-29

244

Nucleus from String Theory  

E-print Network

In generic holographic QCD, we find that baryons are bound to form a nucleus, and that its radius obeys the empirically-known mass number (A) dependence r A^{1/3} for large A. Our result is robust, since we use only a generic property of D-brane actions in string theory. We also show that nucleons are bound completely in a finite volume. Furthermore, employing a concrete holographic model (derived by Hashimoto, Iizuka, and Yi, describing a multi-baryon system in the Sakai-Sugimoto model), the nuclear radius is evaluated as O(1) x A^{1/3} [fm], which is consistent with experiments.

Koji Hashimoto; Takeshi Morita

2011-03-29

245

Improving cosmic string network simulations  

E-print Network

In real-time lattice simulations of cosmic strings in the Abelian Higgs model, the broken translational invariance introduces lattice artefacts; relativistic strings therefore decelerate and radiate. We introduce two different methods to construct a moving string on the lattice, and study in detail the lattice effects on moving strings. We find that there are two types of lattice artefact: there is an effective maximum speed with which a moving string can be placed on the lattice, and a moving string also slows down, with the deceleration approximately proportional to the exponential of the velocity. To mitigate this, we introduce and study an improved discretisation, based on the tree-level L\\"{u}scher-Weisz action, which is found to reduce the deceleration by an order of magnitude, and to increase the string speed limit by an amount equivalent to halving the lattice spacing. The improved algorithm is expected to be very useful for 3D simulations of cosmic strings in the early universe, where one wishes to simulate as large a volume as possible.

Mark Hindmarsh; Kari Rummukainen; Tuomas V. I. Tenkanen; David J. Weir

2014-06-06

246

ISL - A String Manipulating Language.  

ERIC Educational Resources Information Center

The Information Search Language (ISL), described in this report, is a problem-oriented language designed to facilitate the manipulation of real character strings with the Control Data 1604 computer. The report gives instructions for the language; these may be classified as Pseudo-ops, Word-Oriented instructions, Character-string instructions,…

Kelley, K.C.; And Others.

247

Energy in a String Wave  

ERIC Educational Resources Information Center

When one end of a taut horizontal elastic string is shaken repeatedly up and down, a transverse wave (assume sine waveform) will be produced and travel along it. College students know this type of wave motion well. They know when the wave passes by, each element of the string will perform an oscillating up-down motion, which in mechanics is termed…

Ng, Chiu-king

2010-01-01

248

String theory and noncommutative geometry  

Microsoft Academic Search

We extend earlier ideas about the appearance of noncommutative geometry in string theory with a nonzero B-field. We identify a limit in which the entire string dynamics is described by a minimally coupled (supersymmetric) gauge theory on a noncommutative space, and discuss the corrections away from this limit. Our analysis leads us to an equivalence between ordinary gauge fields and

Nathan Seiberg; Edward Witten

1999-01-01

249

Towards inflation in string theory  

Microsoft Academic Search

We investigate the embedding of brane inflation into stable compactifications of string theory. At first sight a warped compactification geometry seems to produce a naturally flat inflaton potential, evading one well known difficulty of brane antibrane scenarios. Careful consideration of the closed string moduli reveals a further obstacle: superpotential stabilization of the compactification volume typically modifies the inflaton potential and

Shamit Kachru; Renata Kallosh; Andrei Linde; Juan Maldacena; Liam McAllister; Sandip P. Trivedi

2003-01-01

250

Small instantons in string theory  

Microsoft Academic Search

A long-standing puzzle about the heterotic string has been what happens when an instanton shrinks to zero size. It is argued here that the answer at the quantum level is that an extra SU(2) gauge symmetry appears that is supported in the core of the instanton. Thus in particular the quantum heterotic string has vacua with higher rank than is

Edward Witten

1996-01-01

251

String theory on group manifolds  

Microsoft Academic Search

A number of issues concerning affine Lie algebras and string propagation on group manifolds are addressed. We show that a 1 + 1 dimensional quantum field theory which gives a realization of current algebra (for any non-abelian Lie group G) will always give rise to an ``integrable'' representation. It is known that string propagation on the group manifold can give

Doron Gepner; Edward Witten

1986-01-01

252

Improving cosmic string network simulations  

NASA Astrophysics Data System (ADS)

In real-time lattice simulations of cosmic strings in the Abelian Higgs model, the broken translational invariance introduces lattice artifacts; relativistic strings therefore decelerate and radiate. We introduce two different methods to construct a moving string on the lattice, and study in detail the lattice effects on moving strings. We find that there are two types of lattice artifact: there is an effective maximum speed with which a moving string can be placed on the lattice, and a moving string also slows down, with the deceleration approximately proportional to the exponential of the velocity. To mitigate this, we introduce and study an improved discretization, based on the tree-level Lüscher-Weisz action, which is found to reduce the deceleration by an order of magnitude, and to increase the string speed limit by an amount equivalent to halving the lattice spacing. The improved algorithm is expected to be very useful for 3D simulations of cosmic strings in the early Universe, where one wishes to simulate as large a volume as possible.

Hindmarsh, Mark; Rummukainen, Kari; Tenkanen, Tuomas V. I.; Weir, David J.

2014-08-01

253

Summing Planar Bosonic Open Strings  

SciTech Connect

In earlier work, planar graphs of massless {phi}{sup 3} theory were summed with the help of the light cone world sheet picture and the mean field approximation. In the present article, the same methods are applied to the problem of summing planar bosonic open strings. They find that in the ground state of the system, string boundaries form a condensate on the world sheet, and a new string emerges from this summation. Its slope is always greater than the initial slope, and it remains non-zero even when the initial slope is set equal to zero. If they assume the initial string tends to a field a theory in the zero slope limit, this result provides evidence for string formation in field theory.

Bardakci, Korkut

2006-02-16

254

String Theory and Water Waves  

E-print Network

We uncover a remarkable role that an infinite hierarchy of non-linear differential equations plays in organizing and connecting certain {hat c}water wave hierarchy. We observe that there are several other string-like limits of the system, and conjecture that some of them are type IIA and IIB (A,D) minimal string backgrounds. We explain how these and several string-like special points arise and are connected. In some cases, the framework endows the theories with a non-perturbative definition for the first time. Notably, we discover that the Painleve IV equation plays a key role in organizing the string theory physics, joining its siblings, Painleve I and II, whose roles have previously been identified in this minimal string context.

Ramakrishnan Iyer; Clifford V. Johnson; Jeffrey S. Pennington

2010-02-05

255

String Mining in Bioinformatics  

NASA Astrophysics Data System (ADS)

Sequence analysis is a major area in bioinformatics encompassing the methods and techniques for studying the biological sequences, DNA, RNA, and proteins, on the linear structure level. The focus of this area is generally on the identification of intra- and inter-molecular similarities. Identifying intra-molecular similarities boils down to detecting repeated segments within a given sequence, while identifying inter-molecular similarities amounts to spotting common segments among two or multiple sequences. From a data mining point of view, sequence analysis is nothing but string- or pattern mining specific to biological strings. For a long time, this point of view, however, has not been explicitly embraced neither in the data mining nor in the sequence analysis text books, which may be attributed to the co-evolution of the two apparently independent fields. In other words, although the word “data-mining” is almost missing in the sequence analysis literature, its basic concepts have been implicitly applied. Interestingly, recent research in biological sequence analysis introduced efficient solutions to many problems in data mining, such as querying and analyzing time series [49,53], extracting information from web pages [20], fighting spam mails [50], detecting plagiarism [22], and spotting duplications in software systems [14].

Abouelhoda, Mohamed; Ghanem, Moustafa

256

String Mining in Bioinformatics  

NASA Astrophysics Data System (ADS)

Sequence analysis is a major area in bioinformatics encompassing the methods and techniques for studying the biological sequences, DNA, RNA, and proteins, on the linear structure level. The focus of this area is generally on the identification of intra- and inter-molecular similarities. Identifying intra-molecular similarities boils down to detecting repeated segments within a given sequence, while identifying inter-molecular similarities amounts to spotting common segments among two or multiple sequences. From a data mining point of view, sequence analysis is nothing but string- or pattern mining specific to biological strings. For a long time, this point of view, however, has not been explicitly embraced neither in the data mining nor in the sequence analysis text books, which may be attributed to the co-evolution of the two apparently independent fields. In other words, although the word "data-mining" is almost missing in the sequence analysis literature, its basic concepts have been implicitly applied. Interestingly, recent research in biological sequence analysis introduced efficient solutions to many problems in data mining, such as querying and analyzing time series [49,53], extracting information from web pages [20], fighting spam mails [50], detecting plagiarism [22], and spotting duplications in software systems [14].

Abouelhoda, Mohamed; Ghanem, Moustafa

257

The Size of Ghost Rods  

E-print Network

'Ghost Rods' are periodic structures in a two-dimensional flow that have an effect on material lines that is similar to real stirring rods. An example is a periodic island: material lines exterior to it must wrap around such an island, because determinism forbids them from crossing through it. Hence, islands act as topological obstacles to material lines, just like physical rods, and lower bounds on the rate of stretching of material lines can be deduced from the motion of islands and rods. Here, we show that unstable periodic orbits can also act as ghost rods, as long as material lines can 'fold' around the orbit, which requires the orbit to be parabolic. We investigate the factors that determine the effective size of ghost rods, that is, the magnitude of their impact on material lines.

Jean-Luc Thiffeault; Emmanuelle Gouillart; Matthew D. Finn

2005-10-29

258

Reactor control rod timing system  

DOEpatents

A fluid driven jet-edge whistle timing system for control rods of a nuclear reactor for producing real-time detection of the timing of each control rod in its scram operation. An important parameter in reactor safety, particularly for liquid metal fast breeder reactors (LMFBR), is the time deviation between the time the control rod is released and the time the rod actually reaches the down position. The whistle has a nearly pure tone signal with center frequency (above 100 kHz) far above the frequency band in which the energy of the background noise is concentrated. Each control rod can be fitted with a whistle with a different frequency so that there is no ambiguity in differentiating the signal from each control rod.

Wu, Peter T. K. (Clifton Park, NY)

1982-01-01

259

Subcritical string and large N QCD  

SciTech Connect

We pursue the possibility of using subcritical string theory in 4 spacetime dimensions to establish a string dual for large N QCD. In particular we study the even G-parity sector of the 4 dimensional Neveu-Schwarz dual resonance model as the natural candidate for this string theory. Our point of view is that the open string dynamics given by this model will determine the appropriate subcritical closed string theory, a tree level background of which should describe the sum of planar multiloop open string diagrams. We examine the one-loop open string diagram, which contains information about the closed string spectrum at weak coupling. Higher loop open string diagrams will be needed to determine closed string interactions. We also analyze the field theory limit of the one-loop open string diagram and recover the correct running coupling behavior of the limiting gauge theory.

Thorn, Charles B. [Institute for Fundamental Theory, Department of Physics, University of Florida, Gainesville Florida 32611 (United States)

2008-10-15

260

Fiber optic laser rod  

DOEpatents

A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

Erickson, G.F.

1988-04-13

261

Hazard Evaluation of Inorganics, Singly and in Mixtures, to Flannelmouth Sucker Catostomus latipinnisin the San Juan River, New Mexico  

Microsoft Academic Search

Larval flannelmouth sucker (Catostomus latipinnis) were exposed to arsenate, boron, copper, molybdenum, selenate, selenite, uranium, vanadium, and zinc singly, and to five mixtures of five to nine inorganics. The exposures were conducted in reconstituted water representative of the San Juan River near Shiprock, New Mexico. The mixtures simulated environmental ratios reported for sites along the San Juan River (San Juan

S. J. Hamilton; K. J. Buhl

1997-01-01

262

Immunocytochemical localization of urotensin I neurons in the caudal neurosecretory system of the white sucker ( Catostomus commersoni )  

Microsoft Academic Search

The localization of urotensin I has been investigated in the caudal neurosecretory system of the white sucker (Catostomus commersoni). The peptide is present in all the cells of the system both large and small, in the large axons passing to the urophysis, and in fine beaded fibres not only within the urophysis but also in a fine plexus lateral to

A. W. F. Fisher; K. Wong; V. Gill; K. Lederis

1984-01-01

263

Accumulation of Hormonally Active Substances by Wild White Sucker (Catostomus commersoni) Exposed to Effluents Discharged to the Wabigoon River  

Microsoft Academic Search

A study was initiated in the spring of 2001 to determine if hormonally active chemicals are bioavailable to white sucker (Catostomus commersoni) residing in the Wabigoon River, downstream of the bleached kraft pulp mill and municipal sewage outfall located in Dryden, Ontario. Females collected during spawning migrations in May 2001 at a near-field expo- sure site exhibited increased condition factor,

Mark Hewitt; Rick Schryer; Andrea Pryce; Andrew Belknap; Barry Firth; Glen Van Der Kraak

264

Seasonal and circannual rhythms in behavioral thermoregulation and their modifications by pinealectomy in the white sucker, Catostomus commersoni  

Microsoft Academic Search

1.Sexually immature white suckers (Catostomus commersoni) were captured at monthly intervals for 20 months and individually placed in horizontal thermal gradients with seasonally appropriate photoperiods and temperature regimes and in a number of cases broad temperature ranges. Fish displayed annual variations in their diel rhythms of behavioral thermoregulation, selecting significantly higher temperatures in the scotophase (D) than the photophase (L),

Martin Kavaliers

1982-01-01

265

Distribution modelling to guide stream fish conservation: an example using the mountain sucker in the Black Hills National Forest, USA  

Microsoft Academic Search

Conservation biologists need tools that can utilize existing data to identify areas with the appropriate habitat for species of conservation concern. Regression models that predict suitable habitat from geospatial data are such a tool. Multiple logistic regression models developed from existing geospatial data were used to identify large- scale stream characteristics associated with the occurrence of mountain suckers (Catostomus platyrhynchus),

Daniel C. Dauwalter; Frank J. Rahel

2008-01-01

266

Trace element concentrations in the dorsal muscle of white suckers and brown bullheads from two acidic Adirondack lakes  

Microsoft Academic Search

Concentrations of 14 elements (Ag, As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn, Tl, V, and Zn) were measured in the dorsal muscle of omnivorous white suckers and brown bullheads, fish likely to ingest sediment while feeding. The fish were collected in two acidic Adirondack lakes known to have elevated concentrations of several of these elements in their

Merrill Heit; Catherine S. Klusek

1985-01-01

267

Utility of the TBARS assay in detecting oxidative stress in white sucker ( Catostomus commersoni) populations exposed to pulp mill effluent  

Microsoft Academic Search

Recent evidence indicates that contaminant-stimulated free radical production and resulting oxidative damage may be an important mechanism of toxicity in organisms exposed to water-borne contaminants. This study tested the hypothesis that increases in oxidative stress and associated biochemical alterations would be present in white sucker (Catostomus commersoni) living in an environment receiving pulp mill effluent. Consistent increases in liver TBARS

Ken D. Oakes; Glen J. Van Der Kraak

2003-01-01

268

Spawning by walleye ( Sander vitreus) and white sucker ( Catostomus commersoni) in the Detroit River: Implications for spawning habitat enhancement  

Microsoft Academic Search

Few active fish spawning grounds have been found in channels connecting the Great Lakes. Here, we describe one near Belle Isle in the Detroit River, part of the channel connecting lakes Huron and Erie. There, in 2005, we collected 1,573 fish eggs, cultured them, and identified the hatched larvae as walleye (Sander vitreus) and white sucker (Catostomus commersoni). Walleye spawning

Bruce A. Manny; Gregory W. Kennedy; James C. Boase; Jeffrey D. Allen; Edward F. Roseman

2010-01-01

269

Spawning migration movements of Lost River and shortnose suckers in the Williamson and Sprague Rivers, Oregon, following the removal of Chiloquin Dam-2009 Annual Report  

USGS Publications Warehouse

The Chiloquin Dam was located at river kilometer (rkm) 1.3 on the Sprague River near the town of Chiloquin, Oregon. The dam was identified as a barrier that potentially inhibited or prevented the upstream spawning migrations and other movements of endangered Lost River suckers (Deltistes luxatus), shortnose suckers (Chasmistes brevirostris), and other fish in the Sprague River. Our research objectives in 2009 were to evaluate adult catostomid spawning migration patterns using radio telemetry to identify and describe shifts in spawning area distribution and migration behavior following the removal of Chiloquin Dam in 2008. We attached external radio transmitters to 58 Lost River suckers and 59 shortnose suckers captured at the Williamson River fish weir. A total of 17 radio-tagged Lost River suckers and one radio-tagged shortnose sucker were detected approaching the site of the former Chiloquin Dam but only two radio-tagged fish (one male Lost River sucker and one female Lost River sucker) were detected crossing upstream of the dam site. A lower proportion of radio-tagged shortnose suckers were detected migrating into the Sprague River when compared with previous years. Detections on remote passive integrated transponder (PIT) tag arrays located in the Sprague River show that although the proportion of fish coming into the Sprague River is small when compared to the number of fish crossing the Williamson River fish weir, the number of fish migrating upstream of the Chiloquin Dam site increased exponentially in the first year since its removal. These data will be used in conjunction with larval production and adult spawning distribution data to evaluate the effectiveness of dam removal in order to provide increased access to underutilized spawning habitat located further upstream in the Sprague River and to reduce the crowding of spawning fish below the dam site.

Ellsworth, Craig M.; VanderKooi, Scott P.

2011-01-01

270

Making Highly Pure Glass Rods  

NASA Technical Reports Server (NTRS)

Proposed quasi-containerless method for making glass rods or fibers minimizes contact between processing equipment and product. Method allows greater range of product sizes and shapes than achieved in experiments on containerless processing. Molten zone established in polycrystalline rod. Furnace sections separated, and glass rod solidifies between them. Clamp supports solid glass as it grows in length. Pulling clamp rapidly away from melt draws glass fiber. Fiber diameter controlled by adjustment of pulling rate.

Naumann, R. J.

1986-01-01

271

Automatic safety rod for reactors  

DOEpatents

An automatic safety rod for a nuclear reactor containing neutron absorbing material and designed to be inserted into a reactor core after a loss-of-core flow. Actuation is based upon either a sudden decrease in core pressure drop or the pressure drop decreases below a predetermined minimum value. The automatic control rod includes a pressure regulating device whereby a controlled decrease in operating pressure due to reduced coolant flow does not cause the rod to drop into the core.

Germer, John H. (San Jose, CA)

1988-01-01

272

String field theory solution for any open string background  

NASA Astrophysics Data System (ADS)

We present an exact solution of open bosonic string field theory which can be used to describe any time-independent open string background. The solution generalizes an earlier construction of Kiermaier, Okawa, and Soler, and assumes the existence of boundary condition changing operators with nonsingular OPEs and vanishing conformal dimension. Our main observation is that boundary condition changing operators of this kind can describe nearly any open string background provided the background shift is accompanied by a timelike Wilson line of sufficient strength. As an application we analyze the tachyon lump describing the formation of a D$(p-1)$-brane in the string field theory of a D$p$-brane, for generic compactification radius. This not only provides a proof of Sen's second conjecture, but also gives explicit examples of higher energy solutions, confirming analytically that string field theory can "reverse" the direction of the worldsheet RG flow. We also find multiple D-brane solutions, demonstrating that string field theory can add Chan-Paton factors and change the rank of the gauge group. Finally, we show how the solution provides a remarkably simple and nonperturbative proof of the background independence of open bosonic string field theory.

Erler, Theodore; Maccaferri, Carlo

2014-10-01

273

Characterization of plasma vitellogenin and sex hormone concentrations during the annual reproductive cycle of the endangered razorback sucker  

USGS Publications Warehouse

Population declines of the endangered razorback sucker Xyrauchen texanus in the Colorado River basin have been attributed to predation by and competition with nonnative fishes, habitat alteration, and dam construction. The reproductive health and seasonal variation of the reproductive end points of razorback sucker populations are currently unknown. Using nonlethal methods, we characterized the plasma hormonal fluctuations of reproductively mature female and male razorback suckers over a 12-month period in a hatchery by measuring their vitellogenin (VTG) and three sex hormones: 17?-estradiol (E2), testosterone (T), and 11-ketotestosterone (KT). Fish were identified as reproductive or nonreproductive based on their body weight, VTG, and sex hormone profiles. In reproductive females, the E2 concentration increased in the fall and winter, and increases in T and VTG concentrations were generally associated with the spawning period. Mean T concentrations were consistently greater in reproductive females than in nonreproductive females, but this pattern was even more pronounced during the spawning period (spring). Consistently low T concentrations (<3 ng/mL) in adult females during the spawning period may indicate reproductive impairment. In reproductive males, spring increases in KT and T concentrations were associated with spawning; concentrations of E2 (<0.48 ng/mL) and VTG (<0.001 mg/mL) were low in males throughout the study. In addition, the E2 : KT ratio and T were the best metrics by which to distinguish female from male adult razorback suckers throughout the year. These metrics of reproductive health and condition may be particularly important to recovery efforts of razorback suckers given that the few remaining wild populations are located in a river where water quality and quantity issues are well documented. In addition to the size, age, and recruitment information currently considered in the recovery goals of this endangered species, reproductive end points could be included as recovery metrics with which to monitor seasonal trends and determine whether repatriated populations are cycling naturally.

Hinck, Jo Ellen; Papoulias, Diana M.; Annis, Mandy L.; Tillitt, Donald E.; Marr, Carrie; Denslow, Nancy D.; Kroll, Kevin J.; Nachtmann, Jason

2011-01-01

274

Hazard assessment of selenium and other trace elements in wild larval razorback sucker from the Green River, Utah  

USGS Publications Warehouse

Contaminant investigations of the Green River in northeastern Utah have documented selenium contamination at sites receiving irrigation drainage. The Green River provides critical habitat for four endangered fishes including the largest extant riverine population of endangered razorback sucker. Although 2175 larval razorback suckers were collected from the river between 1992 and 1996, very few juveniles have been captured within recent decades. Selenium concentrations were measured in larval razorback suckers collected from five sites in the Green River (Cliff Creek, Stewart Lake Drain, Sportsman's Drain, Greasewood Corral, and Old Charlie Wash) to assess the potential for adverse effects on recruitment of larvae to the juvenile stage and the adult population. Larvae from all sites contained mean selenium concentrations ranging from 4.3 to 5.8 ??g/g. These values were at or above the proposed toxic threshold of 4 ??g/g for adverse biological effects in fish, which was derived from several laboratory and field studies with a wide range of fish species. At two sites, Cliff Creek and Stewart Lake Drain, selenium concentrations in larvae increased over time as fish grew, whereas selenium concentrations decreased as fish grew at Sportsman's Drain. Evaluation of a 279-larvae composite analyzed for 61 elements demonstrated that selenium and, to a lesser extent, vanadium were elevated to concentrations reported to be toxic to a wide range of fish species. Elevated selenium concentrations in larval razorback suckers from the five sites suggest that selenium contamination may be widespread in the Green River, and that survival and recruitment of larvae to the juvenile stage may be limited due to adverse biological effects. Selenium contamination may be adversely affecting the reproductive success and recruitment of endangered razorback sucker.

Hamilton, S.J.; Muth, R.T.; Waddell, B.; May, T.W.

2000-01-01

275

HWCTR CONTROL ROD AND SAFETY ROD DRIVE SYSTEMS  

Microsoft Academic Search

The Heavy Water Components Test Reactor (HWCTR) is a pressurized, D\\/sub ; 2\\/O reactor designed for operation up to 70 Mw at 1500 psig and 3l5 deg C. It has ; 18 control rods and six safety rods, each driven by an electric motor through a ; rack and pinion gear train. Racks, pinions, and bearings are located inside ;

Kale

1963-01-01

276

Why are rod-shaped bacteria rod shaped?  

Microsoft Academic Search

Generally speaking, bacteria grow and divide indefinitely, and as long as the growth conditions are maintained they retain constant dimensions and shapes with little variation. How they do this is a question that I have been considering for three decades. Here, I discuss two hypothetical mechanisms, one for Gram-positive rods and the other for Gram-negative rods. These mechanisms are consistent

Arthur L Koch

2002-01-01

277

Liquid-Wall Mass Transfer in Homogeneous Flow with Coaxially Placed String of Hemispheres  

NASA Astrophysics Data System (ADS)

This paper presents a study of mass transfer in an electrochemical cell using the limiting current technique. The liquid-wall mass transfer coefficient is obtained in homogeneous flow employing a coaxially placed string of hemispheres as turbulent promoter by varying the geometric variables of the promoter (pitch, characteristic length, rod diameter) and superficial liquid velocity. Analysis of the data reveals that the mass transfer coefficient increases with increase in characteristic length and rod diameter but decreases with increase in pitch. The mass transfer data were correlated by non linear regression to yield an equation in jD-Re format.

Reddy, G. V. S. K.; Murthy, M. S. N.; Srinivas, B.; Ramesh, K. V.

2014-08-01

278

Control rod support having planar wear surfaces  

Microsoft Academic Search

This patent describes a combination. It comprises: a longitudinally extending rod guide; a support for a control rod. The support being positioned within the rod guide and intended to receive and minimize scarring of the control rod; a cylindrical control rod having a convex surface and being held by a spider including vanes. The support being relatively flat and thin,

L. Veronesi; L. A. Schockling

1990-01-01

279

Bethe Ansatz for Quantum Strings  

NASA Astrophysics Data System (ADS)

We propose Bethe equations for the diagonalization of the hamiltonian of quantum strings on AdS 5 × S 5 at large string tension and restricted to certain large charge states from a closed fraktur sfraktur u(2) subsector. The ansatz differs from the recently proposed all-loop gauge theory asymptotic Bethe ansatz by additional factorized scattering terms for the local excitations. We also show that our ansatz quantitatively reproduces everything that is currently known about the string spectrum of these states. Firstly, by construction, we recover the integral Bethe equations describing semiclassical spinning strings. Secondly, we explain how to derive the 1/J energy corrections of M-impurity BMN states, provide explicit, general formulae for both distinct and confluent mode numbers, and compare to asymptotic gauge theory. In the special cases M = 2,3 we reproduce the results of direct quantization of Callan et al. Lastly, at large string tension and relatively small charge we recover the famous 2(n 2?)1/4 asymptotics of massive string modes at level n. Remarkably, this behavior is entirely determined by the novel scattering terms. This is qualitatively consistent with the conjecture that these terms occur due to wrapping effects in gauge theory. Our finding does not in itself cure the disagreements between gauge and string theory, but leads us to speculate about the structure of an interpolating Bethe ansatz for the AdS/CFT system at finite coupling and charge.

Arutyunov, G.; Frolov, S.; Staudacher, M.

2004-10-01

280

String bit models for superstring  

SciTech Connect

The authors extend the model of string as a polymer of string bits to the case of superstring. They mainly concentrate on type II-B superstring, with some discussion of the obstacles presented by not II-B superstring, together with possible strategies for surmounting them. As with previous work on bosonic string work within the light-cone gauge. The bit model possesses a good deal less symmetry than the continuous string theory. For one thing, the bit model is formulated as a Galilei invariant theory in (D {minus} 2) + 1 dimensional space-time. This means that Poincare invariance is reduced to the Galilei subgroup in D {minus} 2 space dimensions. Naturally the supersymmetry present in the bit model is likewise dramatically reduced. Continuous string can arise in the bit models with the formation of infinitely long polymers of string bits. Under the right circumstances (at the critical dimension) these polymers can behave as string moving in D dimensional space-time enjoying the full N = 2 Poincare supersymmetric dynamics of type II-B superstring.

Bergman, O.; Thorn, C.B.

1995-12-31

281

NL2599 String theory String theories (Green et al., 1987, Davies & Brown, 1988; Polchinski, 1998;  

E-print Network

NL2599 String theory String theories (Green et al., 1987, Davies & Brown, 1988; Polchinski, 1998-like interactions in Feynman graphs are smoothed out in string theory. The quantization of bosonic strings yields that are so small that we don't notice them in daily life. But bosonic string theories have another problem

Beck, Christian

282

String Formatting Considered Harmful for Novice Programmers  

ERIC Educational Resources Information Center

In Java, "System.out.printf" and "String.format" consume a specialised kind of string commonly known as a format string. In our study of first-year students at the Ateneo de Manila University, we discovered that format strings present a substantial challenge for novice programmers. Focusing on their first laboratory we found that 8% of all the…

Hughes, Michael C.; Jadud, Matthew C.; Rodrigo, Ma. Mercedes T.

2010-01-01

283

Emergence String and Mass Formulas of Hadrons  

E-print Network

Assume that hadrons are formed from the emergence string. Usual string should possess two moving states: oscillation and rotation, so we propose corresponding potential and the equation of the emergence string, whose energy spectrum is namely the GMO mass formula and its modified accurate mass formula. These are some relations between the string and observable experimental data.

Yi-Fang Chang

2011-07-19

284

Formation of electron strings in narrow bands  

SciTech Connect

Electron strings may arise in polar materials as a result of an electronic phase separation. The width or the transverse diameter of the string is equal to one interatomic spacing. The length of the string depends on dielectric constants of semiconductors. The appearance of these electron strings may naturally explain the effect of stripe formation observed in a variety of HTSC experiments.

Kusmartsev, F.V.

1999-11-01

285

From Quantum Mechanics to String Theory  

E-print Network

From Quantum Mechanics to String Theory Relativity (why it makes sense) Quantum mechanics Quarks and the Strong Force Symmetry and Unification String Theory: a different kind of unification that is naturally solved by string theory Strings vibrating in a variety of ways give rise to particles of different

286

From Quantum Mechanics to String Theory  

E-print Network

From Quantum Mechanics to String Theory Relativity (why it makes sense) Quantum mechanics Quarks and the Strong Force Symmetry and Unification String Theory: a different kind of unification Friday, June 19, 2009 #12;String Theory Origins We introduced string theory as a possible solution to our

287

Boosted black string bombs  

E-print Network

We study the formation of superradiant bound states for massive scalar fields in five-dimensional rotating black string geometries with a non-vanishing Kaluza-Klein momentum along the compact direction. Even though all Kaluza-Klein modes may form bound states in this geometry, in realistic extra-dimensional models and astrophysical black holes only the zero-mode is sufficiently light for superradiant instabilities to develop, provided the field has a small but non-vanishing mass, as for example for axion-like particles. We use analytical and numerical methods to show that, although the Kaluza-Klein momentum decreases the upper bound on the field mass for an instability to develop, it may enhance its maximum growth rate by more than 50%, thus boosting the black hole bomb mechanism. We discuss the possible observational consequences of this result and its potential as an astrophysical probe of non-trivial extra-dimensional compactifications.

Joao G. Rosa

2012-09-19

288

Boosted black string bombs  

E-print Network

We study the formation of superradiant bound states for massive scalar fields in five-dimensional rotating black string geometries with a non-vanishing Kaluza-Klein momentum along the compact direction. Even though all Kaluza-Klein modes may form bound states in this geometry, in realistic extra-dimensional models and astrophysical black holes only the zero-mode is sufficiently light for superradiant instabilities to develop, provided the field has a small but non-vanishing mass, as for example for axion-like particles. We use analytical and numerical methods to show that, although the Kaluza-Klein momentum decreases the upper bound on the field mass for an instability to develop, it may enhance its maximum growth rate by more than 50%, thus boosting the black hole bomb mechanism. We discuss the possible observational consequences of this result and its potential as an astrophysical probe of non-trivial extra-dimensional compactifications.

Rosa, Joao G

2012-01-01

289

Geometry, topology, and string theory  

SciTech Connect

A variety of scenarios are considered which shed light upon the uses and limitations of classical geometric and topological notions in string theory. The primary focus is on situations in which D-brane or string probes of a given classical space-time see the geometry quite differently than one might naively expect. In particular, situations in which extra dimensions, non-commutative geometries as well as other non-local structures emerge are explored in detail. Further, a preliminary exploration of such issues in Lorentzian space-times with non-trivial causal structures within string theory is initiated.

Varadarajan, Uday

2003-07-10

290

String theory, gravity and experiment  

E-print Network

The aim of these lectures is to give an introduction to several topics which lie at the intersection of string theory, gravity theory and gravity phenomenology. One successively reviews: (i) the "membrane" approach to the dissipative dynamics of classical black holes, (ii) the current experimental tests of gravity, and their theoretical interpretation, (iii) some aspects of the string-inspired phenomenology of the gravitational sector, and (iv) some possibilities for observing string-related signals in cosmology (including a discussion of gravitational wave signals from cosmic superstrings).

Thibault Damour; Marc Lilley

2008-02-28

291

Analysis & Optimization of Connecting Rod  

Microsoft Academic Search

The main objective of this study was to explore weight reduction opportunities for a production forged steel connecting rod. This has entailed performing a detailed load analysis. Therefore, this study has dealt with two subjects, first, static load stress analysis of the connecting rod, and second, optimization for weight. In this project, finite element analysis of single cylinder four stroke

Pranav G. Charkha; Santosh B. Jaju

2009-01-01

292

SAFETY SYSTEM FOR CONTROL ROD  

Microsoft Academic Search

A structure for monitoring the structural continuity of a control rod ; foi a neutron reactor is presented. A electric conductor readily breakable under ; mechanical stress is fastened along the length of the control rod at a plurality ; of positions and forms a closed circuit with remote electrical components ; responsive to an open circuit. A portion of

Paget

1963-01-01

293

Nuclear reactor with control rods  

Microsoft Academic Search

A liquid-cooled nuclear reactor including fuel assemblies mounted within a reactor vessel having linearly movable control rods passing through control rod guide tubes into respective aligned fuel assemblies is described. Reactor coolant circulates through the assemblies. Guide tubes and other vessel internals structures located above the assemblies and is discharged through an outlet nozzle positioned above the elevation of primary

F. D. Obermeyer; R. T. Berringer

1979-01-01

294

Cosmic string catalysis of skyrmion decay  

NASA Technical Reports Server (NTRS)

The Callan-Witten picture is developed for monopole catalyzed skyrmion decay in order to analyze the corresponding cosmic string scenario. It is discovered that cosmic strings (both ordinary and superconducting) can catalyze proton decay, but that this catalysis only occurs on the scale of the core of the string. In order to do this we have to develop a vortex model for the superconducting string. An argument is also given for the difference in the enhancement factors for monopoles and strings.

Gregory, Ruth; Davis, Anne-Christine; Brandenberger, Robert

1988-01-01

295

Charting the landscape of supercritical string theory.  

PubMed

Special solutions of string theory in supercritical dimensions can interpolate in time between theories with different numbers of spacetime dimensions and different amounts of world sheet supersymmetry. These solutions connect supercritical string theories to the more familiar string duality web in ten dimensions and provide a precise link between supersymmetric and purely bosonic string theories. Dimension quenching and c duality appear to be natural concepts in string theory, giving rise to large networks of interconnected theories. PMID:17995316

Hellerman, Simeon; Swanson, Ian

2007-10-26

296

Charting the Landscape of Supercritical String Theory  

SciTech Connect

Special solutions of string theory in supercritical dimensions can interpolate in time between theories with different numbers of spacetime dimensions and different amounts of world sheet supersymmetry. These solutions connect supercritical string theories to the more familiar string duality web in ten dimensions and provide a precise link between supersymmetric and purely bosonic string theories. Dimension quenching and c duality appear to be natural concepts in string theory, giving rise to large networks of interconnected theories.

Hellerman, Simeon; Swanson, Ian [School of Natural Sciences, Institute for Advanced Study Princeton, New Jersey 08540 (United States)

2007-10-26

297

Biomimetic production of silk-like recombinant squid sucker ring teeth proteins.  

PubMed

The sucker ring teeth (SRT) of Humboldt squid exhibit mechanical properties that rival those of robust engineered synthetic polymers. Remarkably, these properties are achieved without a mineral phase or covalent cross-links. Instead, SRT are exclusively made of silk-like proteins called "suckerins", which assemble into nanoconfined ?-sheet reinforced supramolecular networks. In this study, three streamlined strategies for full-length recombinant suckerin protein production and purification were developed. Recombinant suckerin exhibited high solubility and colloidal stability in aqueous-based solvents. In addition, the colloidal suspensions exhibited a concentration-dependent conformational switch, from random coil to ?-sheet enriched structures. Our results demonstrate that recombinant suckerin can be produced in a facile manner in E. coli and processed from mild aqueous solutions into materials enriched in ?-sheets. We suggest that recombinant suckerin-based materials offer potential for a range of biomedical and engineering applications. PMID:25068184

Ding, Dawei; Guerette, Paul A; Hoon, Shawn; Kong, Kiat Whye; Cornvik, Tobias; Nilsson, Martina; Kumar, Akshita; Lescar, Julien; Miserez, Ali

2014-09-01

298

Predation by odonate nymphs on larval razorback suckers (Xyrauchen texanus) under laboratory conditions  

USGS Publications Warehouse

High larval mortality has plagued efforts to raise razorback suckers (Xyrauchen texanus) in a Lake Mohave, Arizona-Nevada backwater. Observations indicate odonate nymph densities may be high enough to impact larval survival. In laboratory tests conducted in aquaria, damselfly (Coenagrionidae: Enallagma sp.) and dragonfly (Libellulidae: Tramea sp.) nymphs consumed 81% and 76% respectively of 11.8 ± 0.7 mm total length larval razorbacks in 7 days compared to 12% mortality in controls. Larger razorback larvae (14 to 15 mm TL) were less susceptible than smaller fish, showing 53% mortality versus 18% in controls. Extensive growth of sago pondweed (Potamogeton pectinatus) may exacerbate predation effects in the backwater, by allowing odonates access to more of the water column.

Horn, Michael J.; Marsh, Paul C.; Mueller, Gordon; Burke, Tom

1994-01-01

299

Topological Mixing with Ghost Rods  

E-print Network

Topological chaos relies on the periodic motion of obstacles in a two-dimensional flow in order to form nontrivial braids. This motion generates exponential stretching of material lines, and hence efficient mixing. Boyland et al. [P. L. Boyland, H. Aref, and M. A. Stremler, J. Fluid Mech. 403, 277 (2000)] have studied a specific periodic motion of rods that exhibits topological chaos in a viscous fluid. We show that it is possible to extend their work to cases where the motion of the stirring rods is topologically trivial by considering the dynamics of special periodic points that we call ghost rods, because they play a similar role to stirring rods. The ghost rods framework provides a new technique for quantifying chaos and gives insight into the mechanisms that produce chaos and mixing. Numerical simulations for Stokes flow support our results.

Emmanuelle Gouillart; Jean-Luc Thiffeault; Matthew D. Finn

2005-10-29

300

Lethal levels of selected water quality variables to larval and juvenile Lost River and shortnose suckers  

USGS Publications Warehouse

Resource managers hypothesize that occasional fish kills during summer-early fall in Upper Klamath Lake, Oregon, may be linked to unfavorable water quality conditions created by massive algal blooms. In a preliminary effort to address this concern, short-term (96-h-long) laboratory tests were conducted with larval and juvenile Lost River (Deltistes luxatus) and shortnose (Chasmistes brevirostris) suckers to determine the upper median lethal concentrations (LC50s; also referred to as median tolerance limits) for pH, un-ionized ammonia, and water temperature, and the lower LC50s for dissolved oxygen. The mean LC50s varied among species and life stages as follows: for pH, 10.30-10.39; for un-ionized ammonia, 0.48-1.06 mg litre-1; for temperature, 30.35-31.82??C; and for dissolved oxygen, 1.34-2.10 mg litre-1. Comparisons of 95% confidence limits indicated that, on average, the 96-h LC50s were not significantly different from those computed for shorter exposure times (i.e., 24 h, 48 h, and 72 h). According to two-way analysis of variance, LC50s for the four water quality variables did not vary significantly (p > 0.05) between fish species. However, LC50s for pH (exposure times of 24 h and 48 h) and dissolved oxygen (exposure times of 48 h, 72 h, and 96 h) differed significantly (p ??? 0.05) between life stages, whereas LC50s for un-ionized ammonia and water temperature did not exhibit significant differences. In general, larvae were more sensitive than juveniles to high pH and low dissolved oxygen concentrations. When compared to ambient water quality conditions in Upper Klamath Lake, our results strongly suggest that near-anoxic conditions associated with the senescence phase of algal blooms are most likely to cause high mortalities of larval and juvenile suckers.

Saiki, M.K.; Monda, D.P.; Bellerud, B.L.

1999-01-01

301

Bullfrog tadpole (Rana catesbeiana) and red swamp crayfish (Procambarus clarkii) predation on early life stages of endangered razorback sucker (Xyrauchen texanus)  

USGS Publications Warehouse

Bullfrog tadpoles (Rana catesbeiana) and red swamp crayfish (Procambarus clarkii) are widespread introduced taxa that are problematic throughout the western United States. Their impact on native amphibians and crustaceans is well documented, but less is known regarding their influence on native fishes. Predator-prey tank tests showed both species consumed eggs and larvae of the endangered razorback sucker (Xyrauchen texanus) in a laboratory setting. Tadpoles consumed 2.2 razorback sucker eggs/d and 1.4 razorback sucker larvae/d, while crayfish ate 6.0 eggs/d and 3.5 larvae/d. Relatively high densities of bullfrog tadpoles and crayfish in razorback sucker spawning areas suggest that these nonnative taxa might pose a threat to the recruitment success of this and other imperiled native fish.

Mueller, G.A.; Carpenter, J.; Thornbrugh, D.

2006-01-01

302

Fast-moving fog--and the well-known "sucker hole" that often accompanies it--surprised another reporter, a  

E-print Network

Fast-moving fog--and the well-known "sucker hole" that often accompanies it-- surprised another was to be at [dawn]. Although I saw there was fog immediately around the airport, it was clear with unrestricted

303

Eichler integrals and String Theory  

E-print Network

In this article, it is shown how to obtain objects called Eichler integrals in the mathematical literature that can be used for calculating scattering amplitudes in String Theory. These Eichler integrals are also new examples of Eichler integrals with poles.

L. Sandoval Jr

1999-09-22

304

String and Sticky Tape Experiments.  

ERIC Educational Resources Information Center

Explains how to demonstrate the fundamentals of one dimensional kinematics such as Newton's third law of motion, and collision between bodies, using simple materials of marbles, strings, sticky tape, drinking straws, and rubber bands. (GA)

Edge, R. D., Ed.

1979-01-01

305

Wave Propagation on a String  

NSDL National Science Digital Library

An animated example of wave propagation on a string composed of two segments of different densities and velocities. Fortran and Unix/GMT source code used to make the animation are available for download from the same site.

306

Spin chains and string theory.  

PubMed

Recently, an important test of the anti de Sitter/conformal field theory correspondence has been done using rotating strings with two angular momenta. We show that such a test can be described more generally as the agreement between two actions: one a low energy description of a spin chain appearing in the field theory side, and the other a limit of the string action in AdS5xS5. This gives a map between the mean value of the spin in the boundary theory and the position of the string in the bulk, and shows how a string action can emerge from a gauge theory in the large-N limit. PMID:15524978

Kruczenski, Martin

2004-10-15

307

String resonances at hadron colliders  

NASA Astrophysics Data System (ADS)

We consider extensions of the standard model based on open strings ending on D-branes, with gauge bosons due to strings attached to stacks of D-branes and chiral matter due to strings stretching between intersecting D-branes. Assuming that the fundamental string mass scale Ms is in the TeV range and that the theory is weakly coupled, we discuss possible signals of string physics at the upcoming HL-LHC run (integrated luminosity =3000 fb-1) with a center-of-mass energy of ?s =14 TeV and at potential future pp colliders, HE-LHC and VLHC, operating at ?s =33 and 100 TeV, respectively (with the same integrated luminosity). In such D-brane constructions, the dominant contributions to full-fledged string amplitudes for all the common QCD parton subprocesses leading to dijets and ? +jet are completely independent of the details of compactification and can be evaluated in a parameter-free manner. We make use of these amplitudes evaluated near the first (n=1) and second (n=2) resonant poles to determine the discovery potential for Regge excitations of the quark, the gluon, and the color singlet living on the QCD stack. We show that for string scales as large as 7.1 TeV (6.1 TeV) lowest massive Regge excitations are open to discovery at the ?5? in dijet (? +jet) HL-LHC data. We also show that for n=1 the dijet discovery potential at HE-LHC and VLHC exceedingly improves: up to 15 TeV and 41 TeV, respectively. To compute the signal-to-noise ratio for n=2 resonances, we first carry out a complete calculation of all relevant decay widths of the second massive level string states (including decays into massless particles and a massive n=1 and a massless particle), where we rely on factorization and conformal field theory techniques. Helicity wave functions of arbitrary higher spin massive bosons are also constructed. We demonstrate that for string scales Ms?10.5 TeV (Ms?28 TeV) detection of n =2 Regge recurrences at HE-LHC (VLHC) would become the smoking gun for D-brane string compactifications. Our calculations have been performed using a semianalytic parton model approach which is cross checked against an original software package. The string event generator interfaces with HERWIG and Pythia through BlackMax. The source code is publicly available in the hepforge repository.

Anchordoqui, Luis A.; Antoniadis, Ignatios; Dai, De-Chang; Feng, Wan-Zhe; Goldberg, Haim; Huang, Xing; Lüst, Dieter; Stojkovic, Dejan; Taylor, Tomasz R.

2014-09-01

308

Strings and Unified Field Theory  

E-print Network

It is argued that string theory predicts unified field theory rather than general relativity coupled to matter fields. In unified field theory all the objects are geometrical, for strings the Kalb-Ramond matter field is identical to the asymmetric part of the metric except that the fields contribute to different sides of the field equations. The dilaton is related to the object of non-metricity.

Mark D. Roberts

2006-07-18

309

Black Holes in String Theory  

Microsoft Academic Search

This is a set of introductory lecture notes on black holes in string theory. After reviewing some aspects of string theory\\u000a such as dualities, brane solutions, supersymmetric and non-extremal intersection rules, we analyze in detail extremal and\\u000a non-extremal 5d black holes. We first present the D-brane counting for extremal black holes. Then we show that 4d and 5d non-extremal black

Kostas Skenderis

2000-01-01

310

In situ hybridization of corticotropin-releasing factor-encoding messenger RNA in the hypothalamus of the white sucker, Catostomus commersoni  

Microsoft Academic Search

In situ hybridization procedure with a 32P-labelled synthetic oligonucleotide probe was used to detect corticotropin-releasing factor-encoding messenger RNA (CRF mRNA) in the hypothalamus of the white sucker, Catostomus commersoni. Adjacent sections were immunostained by a sucker CRF-specific antiserum. CRF mRNA-containing neurons were identified by autoradiography in the magnocellular and parvocellular subdivisions of the preoptic nucleus (PON). Many of these neurons

Yuji Okawara; David Ko; Steven D. Morley; Dietmar Richter; Karl P. Lederis

1992-01-01

311

Movement of Sacramento Sucker, Catostomus occidentalis , and Hitch, Lavinia exilicauda , during a Spring Release of Water from Camanche Dam in the Mokelumne River, California  

Microsoft Academic Search

Synopsis  We recorded the movement of Sacramento suckers, Catostomus occidentalis, and hitch, Lavinia exilicauda, before and during a controlled flood release on a regulated California Central Valley River, using radio telemetry. Both\\u000a species made small, local movements (<550 m) during pre-flood flows. During flood releases, some individual suckers made significantly\\u000a larger movements (>8100 m) both up and downstream of pre-flood flow locations within

Carson A. Jeffres; A. Peter Klimley; Joseph E. Merz; Joseph J. Cech Jr

2006-01-01

312

Effects of temperature and white sucker ( Catostomus commersoni ) serum supplement on the in vitro multiplication of Cryptobia catostomi in cell-free culture medium  

Microsoft Academic Search

Cryptobia catostomi, a non-pathogenic haemoflagellate of white suckers (Catostomus commersoni) multiplied rapidly in modified TDL-15 medium supplemented with 10% fetal bovine serum and 1% heat-inactivated white sucker\\u000a serum (WSS) at 10°C and 18°C. The numbers of C. catostomi counted were significantly higher in cultures incubated at 10°C than in those incubated at 18°C beginning at 3 weeks post-incubation.\\u000a The culture

S. Li; P. T. K. Woo

1996-01-01

313

Concentrations and distribution of Fe, Zn and Cu in tissues of the white sucker (Catostomus commersoni) in relation to elevated levels of metals and low pH  

Microsoft Academic Search

This study examines whether the process of lake acidification influences the accumulation of Fe, Zn and Cu in the tissues of the white sucker (Catostomus commersoni). Concentrations of Fe, Zn and Cu were measured in the liver, kidney and muscle of white sucker sampled from 4 acidic (pH range 4.8–5.3), 1 slightly acidic (pH = 5.8) and 3 circumneutral (pH

Leah Bendell Young; Harold H. Harvey

1989-01-01

314

Rod gripper, changer, and storage system  

NASA Technical Reports Server (NTRS)

A rod changer and storage design is presented for the lunar deep drill apparatus to be used in conjunction with the Skitter walking platform. The design must take into account all of the lunar environment and working conditions. Some of these are: (1) the moon has one sixth the gravity of earth; (2) temperature gradients can range from about -170 to 265 C; (3) because of the high transportation costs, the design must be as light as possible; and (4) the process must be remotely operated (from earth or satellite) and must be automated. Because of Skitter's multiple degree of freedom movement, the design will utilize Skitter's movement to locate an implement and transport it from the rack to the drill string. The implement will be gripped by a thumb and two finger device, identified through an electronic sensing device on the thumb, and transported from the rack to the footplate and back from the footplate to the rack. The major designs discussed in this report have been broken down into three major areas: (1) gripper design (linear transport mechanism); (2) indexing system; and (3) rack design.

Benson, Mark; Demi, Todd; Mcneill, Robert; Waldo, Keith; Afghan, Alex; Oliver, Jim

1989-01-01

315

Geometric precipices in string cosmology  

SciTech Connect

We consider the effects of graviton multiplet fields on transitions between string gas phases. Focusing on the dilaton field, we show that it may obstruct transitions between different thermodynamic phases of the string gas, because the sign of its dimensionally reduced, T-duality invariant, part is conserved when the energy density of the Universe is positive. Thus, many interesting solutions for which this sign is positive end up in a future curvature singularity. Because of this, some of the thermodynamic phases of the usual gravitating string gases behave like superselection sectors. For example, a past-regular Hagedorn phase and an expanding Friedmann-Robertson-Walker (FRW) phase dominated by string momentum modes cannot be smoothly connected in the framework of string cosmology with positive sources. The singularity separates them like a geometric precipice in the moduli space, preventing the dynamics of the theory from bridging across. Sources which simultaneously violate the positivity of energy and null energy condition (NEC) could modify these conclusions. We provide a quantitative measure of positivity of energy and NEC violations that would be necessary for such transitions. These effects must dominate the Universe at the moment of transition, altering the standard gas pictures. At present, it is not known how to construct such sources from first principles in string theory.

Kaloper, Nemanja [Department of Physics, University of California, Davis, California 95616 (United States); Watson, Scott [Michigan Center for Theoretical Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2008-03-15

316

Can GPUs Sort Strings Efficiently?  

E-print Network

Abstract—String sorting or variable-length key sorting has lagged in performance on the GPU even as the fixed-length key sorting has improved dramatically. Radix sorting is the fastest on the GPUs. In this paper, we present a fast and efficient string sort on the GPU that is built on the available radix sort. Our method sorts strings from left to right in steps, moving only indexes and small prefixes for efficiency. We reduce the number of sort steps by adaptively consuming maximum string bytes based on the number of segments in each step. Performance is improved by using Thrust primitives for most steps and by removing singleton segments from consideration. Over 70 % of the string sort time is spent on Thrust primitives. This provides high performance along with high adaptability to future GPUs. We achieve speed of up to 10 over current GPU methods, especially on large datasets. We also scale to much larger input sizes. We present results on easy and difficult strings defined using their after-sort tie lengths. I.

Aditya Deshp; P J Narayanan

317

Ecological effects of a single intraperitoneal injection of [{sup 14}C]-2,3,4,7,8-pentachlorodibenzofuran on feral populations of lake trout and white suckers  

SciTech Connect

In 1989 a total of 24 lake trout and 35 white suckers from a small lake located in the Experimental Lakes Area (ELA) in northwestern Ontario were each targeted with an I.P. injection of [{sup 14}C]-s,3,4,7,8-pentachlorodibenzofuran in corn oil, to a dose of 1 ng{center_dot}g{sup {minus}1}. Fish were tagged, returned to the lake and recaptured during spawning runs in 1990, 1991 and 1992. Sub-samples of treated and control fish were sacrificed each year for residue and biochemical analyses. Treated females were spawned in 1990 and 1991. Analysis of tag-recapture data showed lower survival of treated lake trout over four years. Growth was significantly lower in white suckers in all years but unaffected in lake trout. Fertilization rate of eggs was lower in eggs from treated female white suckers, but not in lake trout. However, only 1 of 4 treated female lake trout recaptured had undergone oogenesis in the last two years of recaptures. Measurements of EROD showed sustained induction in both lake trout and white suckers. Hepatic levels of retinoids were significantly decreased in lake trout but not in white suckers. Calculated half-lives of P{sub 5}CDF were 9.6 years for lake trout and 4.3 years for white suckers. It appears that long term ecological performance was impaired in both species.

Delorme, P.D. [Univ. of Manitoba, Winnipeg (Canada); Lockhart, W.L.; Muir, D.C.G.; Mills, K.H.; Brown, S.B. [Dept. of Fisheries and Oceans, Winnipeg, Manitoba (Canada). Freshwater Inst.

1994-12-31

318

Status of rod consolidation, 1988  

SciTech Connect

It is estimated that the spent fuel storage pools at some domestic light-water reactors will run out of space before 2003, the year that the US Department of Energy currently predicts it will have a repository available. Of the methods being studied to alleviate the problem, rod consolidation is one of the leading candidates for achieving more efficient use of existing space in spent fuel storage pools. Rod consolidation involves mechanically removing all the fuel rods from the fuel assembly hardware (i.e., the structural components) and placing the fuel rods in a close-packed array in a canister without space grids. A typical goal of rod consolidation systems is to insert the fuel rods from two fuel assemblies into a canister that has the same exterior dimensions as one standard fuel assembly (i.e., to achieve a consolidation or compaction ratio of 2:1) and to compact the nonfuel-bearing structural components from those two fuel assemblies by a factor of 10 to 20. This report provides an overview of the current status of rod consolidation in the United States and a small amount of information on related activities in other countries. 85 refs., 36 figs., 5 tabs.

Bailey, W.J.

1989-01-01

319

A novel string field theory solving string theory by liberating left and right movers  

NASA Astrophysics Data System (ADS)

We put forward ideas to a novel string field theory based on making some "objects" that essentially describe "liberated" left- and right- mover fields ( ? + ?) and ( ? - ?) on the string. Our novel string field theory is completely definitely different from any other string theory in as far as a "null set" of information in the string field theory Fock space has been removed relatively, to the usual string field theories. So our theory is definitely new. The main progress is that we manage to make our novel string field theory provide the correct mass square spectrum for the string. We finally suggest how to obtain the Veneziano amplitude in our model.

Nielsen, Holger B.; Ninomiya, Masao

2014-05-01

320

Threading plasmonic nanoparticle strings with light  

NASA Astrophysics Data System (ADS)

Nanomaterials find increasing application in communications, renewable energies, electronics and sensing. Because of its unsurpassed speed and highly tuneable interaction with matter, using light to guide the self-assembly of nanomaterials can open up novel technological frontiers. However, large-scale light-induced assembly remains challenging. Here we demonstrate an efficient route to nano-assembly through plasmon-induced laser threading of gold nanoparticle strings, producing conducting threads 12±2?nm wide. This precision is achieved because the nanoparticles are first chemically assembled into chains with rigidly controlled separations of 0.9?nm primed for re-sculpting. Laser-induced threading occurs on a large scale in water, tracked via a new optical resonance in the near-infrared corresponding to a hybrid chain/rod-like charge transfer plasmon. The nano-thread width depends on the chain mode resonances, the nanoparticle size, the chain length and the peak laser power, enabling nanometre-scale tuning of the optical and conducting properties of such nanomaterials.

Herrmann, Lars O.; Valev, Ventsislav K.; Tserkezis, Christos; Barnard, Jonathan S.; Kasera, Setu; Scherman, Oren A.; Aizpurua, Javier; Baumberg, Jeremy J.

2014-07-01

321

String Cosmology - Large-Field Inflation in String Theory  

E-print Network

This is a short review of string cosmology. We wish to connect string-scale physics as closely as possible to observables accessible to current or near-future experiments. Our possible best hope to do so is a description of inflation in string theory. The energy scale of inflation can be as high as that of Grand Unification (GUT). If this is the case, this is the closest we can possibly get in energy scales to string-scale physics. Hence, GUT-scale inflation may be our best candidate phenomenon to preserve traces of string-scale dynamics. Our chance to look for such traces is the primordial gravitational wave, or tensor mode signal produced during inflation. For GUT-scale inflation this is strong enough to be potentially visible as a B-mode polarization of the cosmic microwave background (CMB). Moreover, a GUT-scale inflation model has a trans-Planckian excursion of the inflaton scalar field during the observable amount of inflation. Such large-field models of inflation have a clear need for symmetry protecti...

Westphal, Alexander

2014-01-01

322

Demographics and Chronology of a Spawning Aggregation of Blue Sucker (Cycleptus elongatus) in the Grand River, Missouri, USA  

USGS Publications Warehouse

The blue sucker (Cycleptus elongatus) was sampled as individuals arrived, spawned, and departed from a spawning riffle in the Grand River of northcentral Missouri, USA. The Grand River basin was not known to support blue sucker reproduction with few individuals ever recorded. The spawning site is unique in character for the lower river. Individuals began arriving in early April when water temperatures reached 10-12??C. Females with freely-flowing roe were sampled in late April after a large rise in river stage and concurrent lowering of the water temperature 4-5 degrees to 16.5??C. The spawning aggregation had a mean age of 15 y and ranged from 9 to 22 y based on scales that probably underestimated true ages. Males outnumbered females 5.5:1. Mean length was 659 mm for males and 721 mm for females. Females were longer at age than males and no significant age-length relationship was evident.

Vokoun, J. C.; Guerrant, T. L.; Rabeni, C. F.

2003-01-01

323

Spawning ecology of flannelmouth sucker, Catostomus lattipinnis (Catostomidae), in two small tributaries of the lower Colorado river  

USGS Publications Warehouse

We report the first published accounts of spawning behavior and spawning site selection of the flannelmouth sucker in two small tributaries of the lower Colorado River in the Grand Canyon, Arizona. Spawning was observed on 20 March 1992 and from 28 March to 10 April 1993 in the Paria River, and from 16 to 19 March 1993 in Bright Angel Creek. Flannelmouth suckers exhibited promiscuous spawning behavior-individual females were typically paired with two or more males for a given event and sometimes changed partners between events. Multiple egg deposits by different females sometimes occurred at one spawning site. Flannelmouth sucker selected substrates from 16 to 32 mm diameter in both streams. Spawning occurred at depths of 10 to 25 cm in the Paria River and 19 to 41 cm in Bright Angel Creek. Mean column water velocities at spawning locations ranged from 0.15 to 1.0 m sec-1 in the Paria River and from 0.23 to 0.89 m sec-1 in Bright Angel Creek. Water temperatures recorded during spawning ranged from 9 to 18??C in the Paria River and 13 to 15??C in Bright Angel Creek. Spawning flannelmouth sucker ascended 9.8 km upstream in the Paria River and 1.25 km in Bright Angel Creek. Spawning females (410-580 mm) were significantly larger than spawning males (385-530 mm) in the Paria River. The mean size of spawning fish in the Paria River was significantly smaller than the entire stock, averaged throughout the study period (380-620 mm). However, fish spawning in 1992-1993 averaged 53 mm larger than fish spawning in the same reach of the Paria River in 1981, indicating a shift in the size structure of this stock.

Weiss, S.J.; Otis, E.O.; Maughan, O.E.

1998-01-01

324

OXIDATIVE STRESS AND ENDOCRINE ENDPOINTS IN WHITE SUCKER (CATOSTOMUS COMMERSONI) FROM A RIVER IMPACTED BY AGRICULTURAL CHEMICALS  

Microsoft Academic Search

Abstract—The effects of agricultural chemicals on cortisol secretion, antioxidants, and lipid peroxidation were investigated in hepatic and adrenal tissue of white sucker (Catostomus commersoni , from a river (Yamaska) that drains an agricultural region in Que ´bec (Canada). Plasma cholinesterase (ChE) activity, used as a biomarker of exposure to pesticides, was elevated in fish from the reference site compared,to fish

Jocelyn Dorval; Vincent Leblond; Christian Deblois; Alice Hontela

2005-01-01

325

Uptake and tissue distribution of manganese in the white sucker (Catostomus commersoni) under conditions of low pH  

Microsoft Academic Search

Concentrations of manganese were determined in the liver, kidney, muscle and bone of white suckers (Catostomus commersoni) from five acid (pH < 5.8), and two circumneutral lakes in south-central Ontario. Manganese tissue concentrations were greater in fish captured from the most acidified lakes with the greatest concentrations of dissolved manganese. These fish had increased concentrations of manganese in the liver,

Leah I. Bendell-Young; Harold H. Harvey

1986-01-01

326

Genetic effects of habitat fragmentation on blue sucker populations in the upper Missouri River ( Cycleptus elongatus Lesueur, 1918)  

Microsoft Academic Search

The blue sucker, Cycleptus elongatus, is a large catostomid fish that occurs in main stem rivers throughout the Mississippi basin of North America. Although not\\u000a federally listed as threatened or endangered, populations are not considered stable in any of 21 states where they occur.\\u000a Included in the range is the Missouri River, which flows more than 3,200 km from Montana to

Michael L. Bessert; Guillermo Ortí

2008-01-01

327

Bioaccumulation of the pharmaceutical 17?-ethinylestradiol in shorthead redhorse suckers ( Moxostoma macrolepidotum) from the St. Clair River, Canada  

Microsoft Academic Search

17?-ethynylestradiol (EE2), a synthetic estrogen prescribed as a contraceptive, was measured in Shorthead Redhorse Suckers (ShRHSs) (Moxostoma macrolepidotum) collected near a wastewater treatment plant (WWTP) in the St. Clair River (Ontario, Canada). We detected EE2 in 50% of the fish samples caught near the WWTP (Stag Island), which averaged 1.6±0.6ng\\/g (wet weight) in males and 1.43±0.96ng\\/g in females. No EE2

Ahmed M. Al-Ansari; Ammar Saleem; Linda E. Kimpe; Jim P. Sherry; Mark E. McMaster; Vance L. Trudeau; Jules M. Blais

2010-01-01

328

Spawning by walleye (Sander vitreus) and white sucker (Catostomus commersoni) in the Detroit River: Implications for spawning habitat enhancement  

USGS Publications Warehouse

Few active fish spawning grounds have been found in channels connecting the Great Lakes. Here, we describe one near Belle Isle in the Detroit River, part of the channel connecting lakes Huron and Erie. There, in 2005, we collected 1,573 fish eggs, cultured them, and identified the hatched larvae as walleye (Sander vitreus) and white sucker (Catostomus commersoni). Walleye spawning peaked during the week of April 12-19; white sucker spawning peaked on May 10. Average areal rate of egg deposition by walleye and white sucker at this spawning ground in 2005 was 346 and 25 eggs/m2, respectively. Our environmental measurements showed that bottom substrates on this spawning ground were largely sand, not optimal for fish reproduction. We hypothesize that reproduction of these fish at this spawning ground could be enhanced by adding rock and gravel substrates for protection of deposited fish eggs and suggest that reproduction by walleye in the Detroit River may add resilience to production of walleye in western Lake Erie. ?? 2010.

Manny, B.A.; Kennedy, G.W.; Boase, J.C.; Allen, J.D.; Roseman, E.F.

2010-01-01

329

String Resonances at Hadron Colliders  

E-print Network

[Abridged] We consider extensions of the standard model based on open strings ending on D-branes. Assuming that the fundamental string mass scale M_s is in the TeV range and that the theory is weakly coupled, we discuss possible signals of string physics at the upcoming HL-LHC run (3000 fb^{-1}) with \\sqrt{s} = 14 TeV, and at potential future pp colliders, HE-LHC and VLHC, operating at \\sqrt{s} = 33 and 100 TeV, respectively. In such D-brane constructions, the dominant contributions to full-fledged string amplitudes for all the common QCD parton subprocesses leading to dijets and \\gamma + jet are completely independent of the details of compactification, and can be evaluated in a parameter-free manner. We make use of these amplitudes evaluated near the first (n=1) and second (n=2) resonant poles to determine the discovery potential for Regge excitations of the quark, the gluon, and the color singlet living on the QCD stack. We show that for string scales as large as 7.1 TeV (6.1 TeV), lowest massive Regge excitations are open to discovery at 5\\sigma in dijet (\\gamma + jet) HL-LHC data. We also show that for n=1, the dijet discovery potential at HE-LHC and VLHC exceedingly improves: up to 15 TeV and 41 TeV, respectively. To compute the signal-to-noise ratio for n=2 resonances, we first carry out a complete calculation of all relevant decay widths of the second massive level string states. We demonstrate that for string scales M_s <~ 10.5 TeV (M_s <~ 28 TeV), detection of n=2 Regge recurrences at HE-LHC (VLHC) would become the smoking gun for D-brane string compactifications. Our calculations have been performed using a semi-analytic parton model approach which is cross checked against an original software package. The string event generator interfaces with HERWIG and Pythia through BlackMax. The source code is publically available in the hepforge repository.

Luis A. Anchordoqui; Ignatios Antoniadis; De-Chang Dai; Wan-Zhe Feng; Haim Goldberg; Xing Huang; Dieter Lust; Dejan Stojkovic; Tomasz R. Taylor

2014-07-30

330

Cosmic Strings from Supersymmetric Flat Directions  

E-print Network

Flat directions are a generic feature of the scalar potential in supersymmetric gauge field theories. They can arise, for example, from D-terms associated with an extra abelian gauge symmetry. Even when supersymmetry is broken softly, there often remain directions in the scalar field space along which the potential is almost flat. Upon breaking a gauge symmetry along one of these almost flat directions, cosmic strings may form. Relative to the standard cosmic string picture based on the abelian Higgs model, these flat-direction cosmic strings have the extreme Type-I properties of a thin gauge core surrounded by a much wider scalar field profile. We perform a comprehensive study of the microscopic, macroscopic, and observational characteristics of this class of strings. We find many differences from the standard string scenario, including stable higher winding mode strings, the dynamical formation of higher mode strings from lower ones, and a resultant multi-tension scaling string network in the early universe. These strings are only moderately constrained by current observations, and their gravitational wave signatures may be detectable at future gravity wave detectors. Furthermore, there is the interesting but speculative prospect that the decays of cosmic string loops in the early universe could be a source of ultra-high energy cosmic rays or non-thermal dark matter. We also compare the observational signatures of flat-direction cosmic strings with those of ordinary cosmic strings as well as (p,q) cosmic strings motivated by superstring theory.

Yanou Cui; Stephen P. Martin; David E. Morrissey; James D. Wells

2007-09-06

331

Testing String Theory with CMB  

E-print Network

Future detection/non-detection of tensor modes from inflation in CMB observations presents a unique way to test certain features of string theory. Current limit on the ratio of tensor to scalar perturbations, r=T/S, is r 10^{-2}-10^{-3}. At present all known string theory inflation models predict tensor modes well below the level of detection. Therefore a possible experimental discovery of tensor modes may present a challenge to string cosmology. The strongest bound on r in string inflation follows from the observation that in most of the models based on the KKLT construction, the value of the Hubble constant H during inflation must be smaller than the gravitino mass. For the gravitino mass in the usual range, m_{3/2} 10^{-3} would imply that the gravitinos in this class of models are superheavy, m_{3/2} > 10^{13} GeV. This would have important implications for particle phenomenology based on string theory.

Renata Kallosh; Andrei Linde

2007-04-05

332

Ultrasonic profilometry system for control rod wear  

Microsoft Academic Search

This patent describes an apparatus for scanning the outer profile of control rods. It comprises a module support positioned at a fixed location with respect to a control rod to be scanned, a transducer drive tube mounted for rotation about the axis of a control rod for receiving a control rod therein, a transducer holder connected to the transducer drive

J. W. Hancock; M. J. Kelly; W. M. Latham; C. E. Stinnett

1991-01-01

333

Fundamental string solutions in open string field theories  

NASA Astrophysics Data System (ADS)

In Witten’s open cubic bosonic string field theory and Berkovits’ superstring field theory we investigate solutions of the equations of motion with appropriate source terms, which correspond to Callan-Maldacena solution in Born-Infeld theory representing fundamental strings ending on the D-branes. The solutions are given in order by order manner, and we show some full order properties in the sense of ?' expansion. In superstring case we show that the solution is 1/2 BPS in full order.

Michishita, Yoji

2006-02-01

334

Thermal Expansion of Long Slender Rods with Forced Convection Cooling along the Rod Length.  

National Technical Information Service (NTIS)

This report presents explicit analytical expressions for the thermal expansion of a rod with heat input at one end and forced convection cooling along the length of the rod. When the rod is graduated for length of the rod. When the rod is graduated for le...

F. F. Rudder

1997-01-01

335

String spectra near some null cosmological singularities  

SciTech Connect

We construct cosmological spacetimes with null Kasner-like singularities as purely gravitational solutions with no other background fields turned on. These can be recast as anisotropic plane-wave spacetimes by coordinate transformations. We analyze string quantization to find the spectrum of string modes in these backgrounds. The classical string modes can be solved for exactly in these time-dependent backgrounds, which enables a detailed study of the near-singularity string spectrum, (time-dependent) oscillator masses, and wave functions. We find that for low-lying string modes (finite oscillation number), the classical near-singularity string mode functions are nondivergent for various families of singularities. Furthermore, for any infinitesimal regularization of the vicinity of the singularity, we find a tower of string modes of ultrahigh oscillation number which propagate essentially freely in the background. The resulting picture suggests that string interactions are non-negligible near the singularity.

Madhu, Kallingalthodi [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India); Narayan, K. [Chennai Mathematical Institute, SIPCOT IT Park, Padur PO, Siruseri 603103 (India)

2009-06-15

336

Acoustic data transmission through a drill string  

DOEpatents

Acoustical signals are transmitted through a drill string by canceling upward moving acoustical noise and by preconditioning the data in recognition of the comb filter impedance characteristics of the drill string. 5 figs.

Drumheller, D.S.

1988-04-21

337

Local cosmic string and C-field  

E-print Network

We investigate a local cosmic string with a phenomenological energy momentum tensor as prescribed by Vilenkin, in presence of C-field . The solutions of full nonlinear Einstein's equations for exterior and interior regions of such a string are presented.

F. Rahaman; R. Mondal; M. Kalam

2006-01-03

338

Black Strings Ending on Horizons  

E-print Network

We construct an approximate static gravitational solution of the Einstein equations, with negative cosmological constant, describing a test black string stretching from the boundary of the Schwarzschild-AdS_5 black brane toward the horizon. The construction builds on a derivative expansion method, assuming that the black brane metric changes slowly along the black string direction. We provide a solution up to second order in derivatives and it implies, in particular, that the black string must shrink to zero size at the horizon of the black brane. In the near horizon region of the black brane, where the two horizons intersect, we provide an exact solution of a cone that describes two intersecting horizons at different temperatures. Moreover, we show that this solution equally describes a thin and long black droplet.

Nidal Haddad

2012-07-10

339

Ambitwistor Strings in Four Dimensions  

NASA Astrophysics Data System (ADS)

We develop ambitwistor string theories for four dimensions to obtain new formulas for tree-level gauge and gravity amplitudes with arbitrary amounts of supersymmetry. Ambitwistor space is the space of complex null geodesics in complexified Minkowski space, and in contrast to earlier ambitwistor strings, we use twistors rather than vectors to represent this space. Although superficially similar to the original twistor string theories of Witten, Berkovits, and Skinner, these theories differ in the assignment of world sheet spins of the fields, rely on both twistor and dual twistor representatives for the vertex operators, and use the ambitwistor procedure for calculating correlation functions. Our models are much more flexible, no longer requiring maximal supersymmetry, and the resulting formulas for amplitudes are simpler, having substantially reduced moduli. These are supported on the solutions to the scattering equations refined according to helicity and can be checked by comparison with corresponding formulas of Witten and of Cachazo and Skinner.

Geyer, Yvonne; Lipstein, Arthur E.; Mason, Lionel

2014-08-01

340

Cosmic strings and black holes  

SciTech Connect

The metric for a Schwarzschild black hole with a cosmic string passing through it is discussed. The thermodynamics of such an object is considered, and it is shown that S = (1/4)A, where S is the entropy and A is the horizon area. It is noted that the Schwarzschild mass parameter M, which is the gravitational mass of the system, is no longer identical to its energy. A solution representing a pair of black holes held apart by strings is discussed. It is nearly identical to a static, axially symmetric solution given long ago by Bach and Weyl. It is shown how these solutions, which were formerly a mathematical curiosity, may be given a more physical interpretation in terms of cosmic strings.

Aryal, M.; Ford, L.H.; Vilenkin, A.

1986-10-15

341

When is a String Like a String? L. Allison, C. S. Wallace and C. N. Yee.  

E-print Network

When is a String Like a String? L. Allison, C. S. Wallace and C. N. Yee. Department of Computer] comes from the analysis of DNA strings. A DNA sequence is a string over the alphabet of four bases {A,C

Allison, Lloyd

342

Joe's Little Book of String1 Class Notes, Phys 230A, String Theory, Winter 2010  

E-print Network

Joe's Little Book of String1 Class Notes, Phys 230A, String Theory, Winter 2010 Last update: 3 of presenting an introduction to the world-sheet approach to string theory which is sufficiently complete pick it up, be unable to put it down, and after staying up all night reading you would know string

Fygenson, Deborah Kuchnir

343

A categorified supergroup for string theory A categorified supergroup for string theory  

E-print Network

A categorified supergroup for string theory A categorified supergroup for string theory John Huerta supergroup for string theory A weak 2-group is a category G with invertible morphisms, equipped object x has a specified weak inverse x: x x = 1 = x x. #12;A categorified supergroup for string theory

Baez, John

344

Suzuki Strings Workshop Saturday, March 15, 2014  

E-print Network

STRING STYLES: Sam Spurbeck, Lansing Linda Gregorian, East Lansing Molly Rebeck, Haslett Linda Gregorian _________________________________________________________________ Parent's name _________________________________________________________________________________ Phone

345

Cambridge Cosmology: Cosmic Strings and Other Defects  

NSDL National Science Digital Library

This section of Cambridge Cosmology discusses cosmic strings and other defects in our Universe. It begins with phase transitions in the early Universe, and how cosmic strings and other defects formed early on. Cosmic string evolution and dynamics are discussed while looking at high-resolution numerical cosmic string simulations. Also covered are possible explanations for the origin of large-scale structures (such as galaxies) and texture models of these structures.

Shellard, Paul; Martins, Carlos; Sornborger, Andrew

346

Combinatorics, observables, and String Theory  

E-print Network

We investigate the most general phase space of configurations, consisting of all possible ways of assigning elementary attributes, ``energies'', to elementary positions, ``cells''. We discuss how this space possesses structures that can be approximated by a quantum-relativistic physical scenario. In particular, we discuss how the Heisenberg's Uncertainty Principle and a universe with a three-dimensional space arise, and what kind of mechanics rules it. String Theory shows up as a complete representation of this structure in terms of time-dependent fields and particles. Within this context, owing to the uniqueness of the underlying mathematical structure it represents, one can also prove the uniqueness of string theory.

Andrea Gregori

2011-03-14

347

Natural Strings in General Relativity  

NASA Astrophysics Data System (ADS)

A generalization of Schrodinger's equation to general relativity using operator replacement and standard differential geometry yields a fourth order wave equation which may be interpreted as a de Broglie string propagating through spacetime. The equation reduces in appropriate limits to the Klein-Gordon equation, and can be easily extended to spinor fields. Unlike previous equations, where mass is a parameter, mass is constrained by the gravity field, analogous to the energies in Schrodinger's equation which are constrained by the potentials. There appear to be no particle-like solutions. Thus, quantum strings may be a natural outgrowth of Schrodinger's quantum theory and Einstein's theory of general relativity.

Vuille, Chris

2000-04-01

348

Chart String Maintenance Project Caf Training  

E-print Network

Chart String Maintenance Project Café Training NUPlans Course FMS705 April 12, 2012 #12;Budget Analyze with Summaries and Reports Submit and Review Review Chart Strings and Add Accounts #12;2 Agenda · Introduce NUPlans Web · Walk through Chart String Maintenance Add Grant Proposal Add Account to Chart

Shull, Kenneth R.

349

On Cosmologically Induced Hierarchies in String Theory  

Microsoft Academic Search

We propose, within a perturbative string theory example, a cosmological way to generate a large hierarchy between the observed Planck mass and the fundamental string scale. Time evolution results in three large space dimensions, one additional dimension transverse to our world and five small internal dimensions with a very slow time evolution. The evolution of the string coupling and internal

E. Dudas; J. Mourad; C. Timirgaziu

2004-01-01

350

On Cosmologically Induced Hierarchies in String Theory  

Microsoft Academic Search

We propose, within a perturbative string theory example, a cosmological way to generate a large hierarchy between the observed Planck mass and the fundamental string scale. Time evolution results in three large space dimensions, one additional dimension transverse to our world and five small internal dimensions with a very slow time evolution. The evolution of the string coupling and internal

E. Dudas; J. Mourad; C. Timirgaziu

2003-01-01

351

Lectures on string\\/brane cosmology  

Microsoft Academic Search

An overview is presented of some cosmological aspects of string theory. Recent developments are emphasised, especially the attempts to derive inflation or alternatives to inflation from the dynamics of branes in string theory. Time dependent backgrounds with potential cosmological implications, such as those provided by negative tension branes and S-branes and the rolling string tachyon are also discussed.

Fernando Quevedo

2002-01-01

352

Black holes, entropy functionals, and topological strings  

Microsoft Academic Search

This thesis is devoted to study of the connection between extremal black holes and topological strings. Important ingredient of this connection is the relation between Hartle-Hawking wave function associated to black holes and topological string partition function. This leads to a natural entropy functional defined on the moduli space of string compactifications. We discuss several examples of such entropy functionals.

Kirill Anatolyevich Saraikin

2007-01-01

353

String Field Theory Around the Tachyon Vacuum  

Microsoft Academic Search

Assuming that around the tachyon vacuum the kinetic term of cubic open string field theory is made purely of ghost operators we are led to gauge invariant actions which manifestly implement the absence of open string dynamics around this vacuum. We test this proposal by showing the existence of lump solutions of arbitrary codimension in this string field theory. The

Leonardo Rastelli; Ashoke Sen; Barton Zwiebach

2000-01-01

354

String Theory at Snowmass Michael Dine  

E-print Network

String Theory at Snowmass Michael Dine Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064 (Dated: September 23, 2002) This is the summary talk for the String Theory interested in string theory, quantum gravity, and related issues met to discuss the questions: which future

California at Santa Cruz, University of

355

From Quantum Mechanics to String Theory  

E-print Network

From Quantum Mechanics to String Theory Relativity (why it makes sense) Quantum mechanics Quarks and the Strong Force Symmetry and Unification String Theory: a different kind of unification from the interaction energy Thursday, June 4, 2009 #12;String Theory: A different kind of unification

356

Transverse structure of the QCD string  

SciTech Connect

The characterization of the transverse structure of the QCD string is discussed. We formulate a conjecture as to how the stress-energy tensor of the underlying gauge theory couples to the string degrees of freedom. A consequence of the conjecture is that the energy density and the longitudinal-stress operators measure the distribution of the transverse position of the string, to leading order in the string fluctuations, whereas the transverse-stress operator does not. We interpret recent numerical measurements of the transverse size of the confining string and show that the difference of the energy and longitudinal-stress operators is a particularly natural probe at next-to-leading order. Second, we derive the constraints imposed by open-closed string duality on the transverse structure of the string. We show that a total of three independent ''gravitational'' form factors characterize the transverse profile of the closed string, and obtain the interpretation of recent effective string theory calculations: the square radius of a closed string of length {beta} defined from the slope of its gravitational form factor, is given by (d-1/2{pi}{sigma})log({beta}/4r{sub 0}) in d space dimensions. This is to be compared with the well-known result that the width of the open string at midpoint grows as (d-1/2{pi}{sigma})log(r/r{sub 0}). We also obtain predictions for transition form factors among closed-string states.

Meyer, Harvey B. [Johannes Gutenberg Universitaet Mainz, Institut fuer Kernphysik, 55099 Mainz (Germany)

2010-11-15

357

Reminiscence on the Birth of String Theory  

E-print Network

These are my personal impressions of the environment in which string theory was born, and what the important developments affecting my work were during the hadronic string era, 1968-1974. I discuss my motivations and concerns at the time, particularly in my work on loop amplitudes and on closed strings.

Joel A. Shapiro

2007-11-21

358

Conformal invariance, supersymmetry and string theory  

Microsoft Academic Search

Covariant quantization of string theories is developed in the context of conformal field theory and the BRST quantization procedure. The BRST method is used to covariantly quantize superstrings, and in particular to construct the vertex operators for string emission as well as the supersymmetry charge. The calculation of string loop diagrams is sketched. We discuss how conformal methods can be

Daniel Friedan; Emil Martinec; Stephen Shenker

1986-01-01

359

A First Course in String Theory  

Microsoft Academic Search

An accessible introduction to string theory, this book provides a detailed and self-contained demonstration of the main concepts involved. The first part deals with basic ideas, reviewing special relativity and electromagnetism while introducing the concept of extra dimensions. D-branes and the classical dynamics of relativistic strings are discussed next, and the quantization of open and closed bosonic strings in the

Barton Zwiebach

2004-01-01

360

String theory dynamics in various dimensions  

Microsoft Academic Search

The strong coupling dynamics of string theories in dimension d ? 4 are studied. It is argued, among other things, that eleven-dimensional supergravity arises as a low energy limit of the ten-dimensional Type IIA superstring, and that a recently conjectured duality between the heterotic string and Type IIA superstrings controls the strong coupling dynamics of the heterotic string in five,

Edward Witten

1995-01-01

361

TOPOLOGICAL STRING THEORY AND ENUMERATIVE GEOMETRY  

E-print Network

TOPOLOGICAL STRING THEORY AND ENUMERATIVE GEOMETRY a dissertation submitted to the department) Approved for the University Committee on Graduate Studies: iii #12;TOPOLOGICAL STRING THEORY In this thesis we investigate several problems which have their roots in both topolog- ical string theory

Slatkin, Montgomery

362

Noncommutative Tachyons And String Field Theory  

Microsoft Academic Search

It has been shown recently that by turning on a large noncommutativity parameter, the description of tachyon condensation in string theory can be drastically simplified. We reconsider these issues from the standpoint of string field theory, showing that, from this point of view, the key fact is that in the limit of a large B-field, the string field algebra factors

Edward Witten

2000-01-01

363

Field-theory approach for strings  

Microsoft Academic Search

An approach to string theory is developed on the basis of a covariant effective action for fields corresponding to the excitation modes of the string. Both closed and open bosonic strings are considered. A low-energy approximation to the effective action is derived and the structure of the interactions of the dilation field is established.

Tsei-brevetlin

1986-01-01

364

White sucker (Catostomus commersoni) growth and sexual maturation in pulp mill-contaminated and reference rivers  

SciTech Connect

Induction of hepatic ethoxyresorufin-O-deethylase (EROD) activity and accumulation of chlorophenolic compounds typical of bleached-kraft mill effluent (BKME) in fish sampled downstream of a pulp mill on the St. Maurice River, Quebec, Canada, provided evidence of chemical exposure to BKME. In comparison, fish sampled over the same distances and in similar habitats in a noncontaminated reference river, the Gatineau River, demonstrated low EROD activity and contamination levels. Accelerated growth of white suckers occurred between 2 and 10 years of age in both rivers at downstream stations relative to upstream stations, suggesting the existence of gradients of nutrient enrichment independent of BKME contamination. The impact of BKME exposure was expressed as reduced investment in reproduction, as revealed by greater length at maturity, reduced gonad size, and more variable fecundity. These effects were not obvious in simple upstream-downstream comparisons, but became evident when fish from the uncontaminated Gatineau River showed increased gonadal development and reduced age and size at maturity in response to enhanced growth rates.

Gagnon, M.M.; Bussieres, D.; Dodson, J.J. (Univ. Laval, Sainte-Foy, Quebec (Canada)); Hodson, P.V. (Canada Center for Inland Waters, Burlington, Ontario (Canada))

1995-02-01

365

Nanoconfined ?-sheets mechanically reinforce the supra-biomolecular network of robust squid Sucker Ring Teeth.  

PubMed

The predatory efficiency of squid and cuttlefish (superorder Decapodiformes) is enhanced by robust Sucker Ring Teeth (SRT) that perform grappling functions during prey capture. Here, we show that SRT are composed entirely of related structural “suckerin” proteins whose modular designs enable the formation of nanoconfined ?-sheet-reinforced polymer networks. Thirty-seven previously undiscovered suckerins were identified from transcriptomes assembled from three distantly related decapodiform cephalopods. Similarity in modular sequence design and exon–intron architecture suggests that suckerins are encoded by a multigene family. Phylogenetic analysis supports this view, revealing that suckerin genes originated in a common ancestor ~350 MYa and indicating that nanoconfined ?-sheet reinforcement is an ancient strategy to create robust bulk biomaterials. X-ray diffraction, nanomechanical, and micro-Raman spectroscopy measurements confirm that the modular design of the suckerins facilitates the formation of ?-sheets of precise nanoscale dimensions and enables their assembly into structurally robust supramolecular networks stabilized by cooperative hydrogen bonding. The suckerin gene family has likely played a key role in the evolutionary success of decapodiform cephalopods and provides a large molecular toolbox for biomimetic materials engineering. PMID:24911543

Guerette, Paul A; Hoon, Shawn; Ding, Dawei; Amini, Shahrouz; Masic, Admir; Ravi, Vydianathan; Venkatesh, Byrappa; Weaver, James C; Miserez, Ali

2014-07-22

366

Time-series analysis reveals genetic responses to intensive management of razorback sucker (Xyrauchen texanus)  

PubMed Central

Time-series analysis is used widely in ecology to study complex phenomena and may have considerable potential to clarify relationships of genetic and demographic processes in natural and exploited populations. We explored the utility of this approach to evaluate population responses to management in razorback sucker, a long-lived and fecund, but declining freshwater fish species. A core population in Lake Mohave (Arizona-Nevada, USA) has experienced no natural recruitment for decades and is maintained by harvesting naturally produced larvae from the lake, rearing them in protective custody, and repatriating them at sizes less vulnerable to predation. Analyses of mtDNA and 15 microsatellites characterized for sequential larval cohorts collected over a 15-year time series revealed no changes in geographic structuring but indicated significant increase in mtDNA diversity for the entire population over time. Likewise, ratios of annual effective breeders to annual census size (Nb/Na) increased significantly despite sevenfold reduction of Na. These results indicated that conservation actions diminished near-term extinction risk due to genetic factors and should now focus on increasing numbers of fish in Lake Mohave to ameliorate longer-term risks. More generally, time-series analysis permitted robust testing of trends in genetic diversity, despite low precision of some metrics. PMID:24665337

Dowling, Thomas E; Turner, Thomas F; Carson, Evan W; Saltzgiver, Melody J; Adams, Deborah; Kesner, Brian; Marsh, Paul C

2014-01-01

367

Relative sensitivity of three endangered fishes, Colorado squawfish, bonytail, and razorback sucker, to selected metal pollutants  

USGS Publications Warehouse

The acute toxicity of four metal pollutants to larval and juvenile stages of endangered Colorado squawfish (Ptychocheilus lucius), bonytail (Gila elegans), and razorback sucker (Xyrauchen texanus) were determined in a water quality representative of that in the Green River, Utah. The rank order of toxicity (96-hr LC50) of the metals to all species and life stages from most toxic to least toxic was mercury (57-168 ??G/liter) > cadmium (78-168 pg/liter) > hexavalent chromium (32,000-123,000 ??g/liter) > lead (>170,000 ??G/liter). In tests with lead, a precipitate formed in all test solutions and no mortalities occurred in these treatments. The larvae of each species were as sensitive or more sensitive than the juveniles to cadmium, hexavalent chromium, and mercury. Overall, the three species exhibited similar sensitivities to cadmium, hexavalent chromium, and mercury. Comparison of test results for the juveniles with toxicity values reported for other freshwater fishes tested in different water qualities indicates that the endangered fishes are more sensitive to cadmium than other cyprinids and centrarchids and less sensitive than salmonids, whereas their sensitivity to hexavalent chromium and mercury is similar to that of other cyprinids, centrarchids, and salmonids.

Buhl, K.J.

1997-01-01

368

On the string Lie algebra.  

E-print Network

We construct an abelian representative for the crossed module associated to the string Lie algebra. We show how to apply this construction in order to define quasi-invariant tensors which serve to categorify the infinitesimal braiding on the category of g-modules given by an r-matrix, following Cirio-Martins.

Salim Riviere; Friedrich Wagemann

369

Primordial Fluctuations in String Cosmology  

Microsoft Academic Search

This thesis is dedicated to the study of inflationary scenarios based on string theory. Inflation is a brief period of accelerated expansion in the very early Universe which gives natural explanations for problems of the Standard Big Bang Model (SBBM) of cosmology. The phenomenological success of inflation provides the motivation for numerous efforts to establish its connection with particle physics.

Larissa C. Lorenz

2010-01-01

370

Apparatus in a drill string  

Microsoft Academic Search

An apparatus in a drill string comprises an internally upset drill pipe. The drill pipe comprises a first end, a second end, and an elongate tube intermediate the first and second ends. The elongate tube and the ends comprising a continuous an inside surface with a plurality of diameters. A conformable spirally welded metal tube is disposed within the drill

David R. Hall; Scott Dahlgren; Hall Jr. Tracy H; Joe Fox; David S. Pixton

2007-01-01

371

Winding Strings in Singular Spacetimes  

E-print Network

Evolution of winding strings in spacetimes with cycles whose proper lengths depend on time is examined. It was established earlier that extended objects wrapping the shrinking dimension in compactified Milne spacetime enjoy classically nonsingular evolution. Extensions of this observation to other spacetimes are discussed.

Marek Pawlowski; Wlodzimierz Piechocki; Michal Spalinski

2005-07-14

372

Topological Strings from Quantum Mechanics  

E-print Network

We propose a general correspondence which associates a non-perturbative quantum-mechanical operator to a toric Calabi-Yau manifold, and we conjecture an explicit formula for its spectral determinant in terms of an M-theoretic version of the topological string free energy. As a consequence, we derive an exact quantization condition for the operator spectrum, in terms of the vanishing of a generalized theta function. The perturbative part of this quantization condition is given by the Nekrasov-Shatashvili limit of the refined topological string, but there are non-perturbative corrections determined by the conventional topological string. We analyze in detail the cases of local P2, local P1xP1 and local F1. In all these cases, the predictions for the spectrum agree with the existing numerical results. We also show explicitly that our conjectured spectral determinant leads to the correct spectral traces of the corresponding operators, which are closely related to topological string theory at orbifold points. Phys...

Grassi, Alba; Marino, Marcos

2014-01-01

373

String Embeddings of the Pentagon  

E-print Network

The Pentagon Model is an explicit supersymmetric extension of the Standard Model, which involves a new strongly-interacting SU(5) gauge theory at TeV-scale energies. We discuss embeddings of the Pentagon Model into string theory, specifically N=1 supersymmetric type IIa intersecting D-brane models, M-theory compactifications of G_2 holonomy, and heterotic orbifold constructions.

Echols, Sean

2010-01-01

374

String Embeddings of the Pentagon  

E-print Network

The Pentagon Model is an explicit supersymmetric extension of the Standard Model, which involves a new strongly-interacting SU(5) gauge theory at TeV-scale energies. We discuss embeddings of the Pentagon Model into string theory, specifically N=1 supersymmetric type IIa intersecting D-brane models, M-theory compactifications of G_2 holonomy, and heterotic orbifold constructions.

Sean Echols

2010-05-02

375

String theory in target space  

E-print Network

It is argued that the complete S-matrix of string theory at tree level in a flat background can be obtained from a small set of target space properties, without recourse to the worldsheet description. The main non-standard inputs are (generalised) Britto-Cachazo-Feng-Witten shifts, as well as the monodromy relations for open string theory and the Kawai-Lewellen-Tye relations for closed string theory. The roots of the scattering amplitudes and especially their appearance in the residues at the kinematic poles are central to the story. These residues determine the amplitudes through on-shell recursion relations. Several checks of the formalism are presented, including a computation of the Koba-Nielsen amplitude in the bosonic string. Furthermore the question of target space unitarity is (re-)investigated. For the Veneziano amplitude this question is reduced by Poincare invariance, unitarity and locality to that of positivity of a particular numerical sum. Interestingly, this analysis produces the main conditions of the no-ghost theorem on dimension and intercept from the first three poles of this amplitude.

Rutger H. Boels; Tobias Hansen

2014-02-25

376

String universality in ten dimensions.  

PubMed

We show that the N=1 supergravity theories in ten dimensions with gauge groups U(1){496} and E{8}×U(1){248} are not consistent quantum theories. Cancellation of anomalies cannot be made compatible with supersymmetry and Abelian gauge invariance. Thus, in ten dimensions all supersymmetric theories of gravity without known inconsistencies are realized in string theory. PMID:20868028

Adams, Allan; Taylor, Washington; Dewolfe, Oliver

2010-08-13

377

String Physics at the LHC  

SciTech Connect

The LHC program will include the identification of events with single high-k{sub T} photons as probes of new physics. We show that this channel is uniquely suited to search for experimental evidence of TeV-scale open string theory.

Anchordoqui, Luis A. [Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53201 (United States)

2008-11-23

378

On Closed Twistor String Theory  

E-print Network

The Heterotic twistor string theory of Mason and Skinner is investigated with particular attention given to the role of topological gravity on the world-sheet. The general structure of scattering amplitudes is discussed and expressed in terms of an integral over the moduli space of super Riemann surfaces.

R. A. Reid-Edwards

2012-12-25

379

String Universality in Ten Dimensions  

SciTech Connect

We show that the N=1 supergravity theories in ten dimensions with gauge groups U(1){sup 496} and E{sub 8}xU(1){sup 248} are not consistent quantum theories. Cancellation of anomalies cannot be made compatible with supersymmetry and Abelian gauge invariance. Thus, in ten dimensions all supersymmetric theories of gravity without known inconsistencies are realized in string theory.

Adams, Allan; Taylor, Washington; DeWolfe, Oliver [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Department of Physics, 390 UCB, University of Colorado, Boulder, Colorado 80309 (United States)

2010-08-13

380

Spin chains and string theory  

Microsoft Academic Search

Recently, an impressive agreement was found between anomalous dimen- sions of certain operators in N = 4 SYM and rotating strings with two angular mo- menta in the bulk of AdS5 × S5. A one-loop field theory computation, which involves solving a Heisenberg chain by means of the Bethe ansatz agrees with the large angular momentum limit of a rotating

Martin Kruczenski

381

Natural Strings in General Relativity  

Microsoft Academic Search

A generalization of Schrodinger's equation to general relativity using operator replacement and standard differential geometry yields a fourth order wave equation which may be interpreted as a de Broglie string propagating through spacetime. The equation reduces in appropriate limits to the Klein-Gordon equation, and can be easily extended to spinor fields. Unlike previous equations, where mass is a parameter, mass

Chris Vuille

2000-01-01

382

Cosmic string detection in radio surveys  

NASA Astrophysics Data System (ADS)

We consider the detection of cosmic strings using observations of the anisotropy of the Cosmic Microwave Background. Several methods for detecting cosmic strings are analyzed, using a threshold filter and expansion in orthogonal Haar functions. Computer simulation provides estimates of the noise present in experiments aimed at detection of cosmic strings. Attempts to detect cosmic strings were carried out using the full-sky ILC map obtained as a result of the WMAP space mission. A list of cosmic string candidates has been compiled using the Haar function method.

Sazhina, O. S.; Sementsov, V. N.; Ashimbaeva, N. T.

2014-01-01

383

Light Z' in heterotic string standardlike models  

NASA Astrophysics Data System (ADS)

The discovery of the Higgs boson at the LHC supports the hypothesis that the Standard Model provides an effective parametrization of all subatomic experimental data up to the Planck scale. String theory, which provides a viable perturbative approach to quantum gravity, requires for its consistency the existence of additional gauge symmetries beyond the Standard Model. The construction of heterotic string models with a viable light Z' is, however, highly constrained. We outline the construction of standardlike heterotic string models that allow for an additional Abelian gauge symmetry that may remain unbroken down to low scales. We present a string inspired model, consistent with the string constraints.

Athanasopoulos, P.; Faraggi, A. E.; Mehta, V. M.

2014-05-01

384

Charting the landscape of supercritical string theory  

E-print Network

Special solutions of string theory in supercritical dimensions can interpolate in time between theories with different numbers of spacetime dimensions (via dimension quenching) and different amounts of worldsheet supersymmetry (via c-duality). These solutions connect supercritical string theories to the more familiar string duality web in ten dimensions, and provide a precise link between supersymmetric and purely bosonic string theories. Dimension quenching and c-duality appear to be natural concepts in string theory, giving rise to large networks of interconnected theories. We describe some of these networks in detail and discuss general consistency constraints on the types of transitions that arise in this framework.

Simeon Hellerman; Ian Swanson

2007-05-08

385

The Official String Theory Web Site  

NSDL National Science Digital Library

The Official String Theory Web Site, created by a group of highly educated physicists, is a great resource for everyone interested in physics and the string theory. It begins with educational and stimulating discussion about theoretical physics and the basics of string theory. Users can find out about the experimental tests and the math used by string theorists. Visitors can take a trip through the Big Bang, view amazing images of black holes, and learn about the history of string theory. Students and educators can listen to interviews of the many scientists who contributed to this informative site.

386

Stuck fuel rod capping sleeve  

DOEpatents

A stuck fuel rod capping sleeve to be used during derodding of spent fuel assemblies if a fuel rod becomes stuck in a partially withdrawn position and, thus, has to be severed. The capping sleeve has an inner sleeve made of a lower work hardening highly ductile material (e.g., Inconel 600) and an outer sleeve made of a moderately ductile material (e.g., 304 stainless steel). The inner sleeve may be made of an epoxy filler. The capping sleeve is placed on a fuel rod which is then severed by using a bolt cutter device. Upon cutting, the capping sleeve deforms in such a manner as to prevent the gross release of radioactive fuel material

Gorscak, Donald A. (Bethel Park, PA); Maringo, John J. (McKeesport, PA); Nilsen, Roy J. (Upper St. Clair, PA)

1988-01-01

387

Dynamics in Semidilute Rod Suspensions  

NASA Astrophysics Data System (ADS)

While shear-thinning in semidilute suspensions of rod-like particles has been widely observed, the underlying mechanisms are often unclear. We have developed a model system of fluorescent SU-8 rods suspended in a Glycerol/Ethylene-Glycol solution. This model system exhibits an order of magnitude difference in apparent viscosity at low shear rates as compared to high shear rates while showing no discernible difference in structure. Using a coupled confocal microscope and rheometer instrument along with fiber identification and particle tracking routines, we directly image and quantify the 3D structure and dynamics of our model system under shear flow in order to determine how particle interactions could be generating the observed shear thinning. In particular we look at how interactions modify Jeffery's orbits in semidilute suspensions as compared to the motion of an isolated rod or ellipsoid.

Kumar, Pramukta; Blair, Dan; Urbach, Jeffrey

2012-02-01

388

Advanced gray rod control assembly  

DOEpatents

An advanced gray rod control assembly (GRCA) for a nuclear reactor. The GRCA provides controlled insertion of gray rod assemblies into the reactor, thereby controlling the rate of power produced by the reactor and providing reactivity control at full power. Each gray rod assembly includes an elongated tubular member, a primary neutron-absorber disposed within the tubular member said neutron-absorber comprising an absorber material, preferably tungsten, having a 2200 m/s neutron absorption microscopic capture cross-section of from 10 to 30 barns. An internal support tube can be positioned between the primary absorber and the tubular member as a secondary absorber to enhance neutron absorption, absorber depletion, assembly weight, and assembly heat transfer characteristics.

Drudy, Keith J; Carlson, William R; Conner, Michael E; Goldenfield, Mark; Hone, Michael J; Long, Jr., Carroll J; Parkinson, Jerod; Pomirleanu, Radu O

2013-09-17

389

Synchrotron radiation of superconducting cosmic strings  

NASA Astrophysics Data System (ADS)

Cosmic strings are topological defects which can be formed during the symmetry breaking phase transitions in the early Universe. Their existence finds support in modern superstring theories, both in compactification models and in theories with extended additional dimensions. Strings predicted in most grand unified models respond to external electromagnetic fields as thin superconducting wires. As they move through the cosmic magnetic fields, strings develop tremendous electric currents. Superconducting cosmic strings can serve as powerful sources of nonthermal radiation in a wide energy range, viz. as synchrotron radiation of electrons accelerated by bow shock waves which are created by the magnetosphere of strings moving relativistically through the intergalactic medium (IGM). Calculations of the expected radiation fluxes show that for typical parameters of the strings and the IGM the existing detectors can see loops at average string distances. According to our calculations they can also be observed if they are located in clusters of galaxies.

Rogozin, D. A.; Zadorozhna, L. V.

2013-11-01

390

The Resurgence of Instantons in String Theory  

E-print Network

Nonperturbative effects in string theory are usually associated to D-branes. In many cases it can be explicitly shown that D-brane instantons control the large-order behavior of string perturbation theory, leading to the well-known (2g)! growth of the genus expansion. This paper presents a detailed treatment of nonperturbative solutions in string theory, and their relation to the large-order behavior of perturbation theory, making use of transseries and resurgent analysis. These are powerful techniques addressing general nonperturbative contributions within non-linear systems, which are developed at length herein as they apply to string theory. The cases of topological strings, the Painleve I equation describing 2d quantum gravity, and the quartic matrix model, are explicitly addressed. These results generalize to minimal strings and general matrix models. It is shown that, in order to completely understand string theory at a fully nonperturbative level, new sectors are required beyond the standard D-brane sector.

Inês Aniceto; Ricardo Schiappa; Marcel Vonk

2011-06-29

391

Response of white sucker (Catostomus commersoni) to pulp and paper mill effluent in the Androscoggin River, Maine, USA.  

PubMed

Adverse effects of pulp and paper mill effluent on fish populations have been well documented in many countries over the last two decades. Some of the initial studies were at mills with conventional chlorine bleaching and no secondary effluent treatment. Following installation of secondary treatment, changes in bleaching technology to elemental chlorine-free bleaching, and other process changes, adverse effects on fish were reduced or eliminated at some mills. Because no two mills are exactly alike, it is difficult to predict adverse impacts of any given mill on fish populations. In 1994, a study of female white sucker (Catostomus commersoni) in the Androscoggin River, Maine, USA, showed induction of mixed function oxidase, reductions in gonad size and plasma estradiol, and an increase in plasma testosterone in fish downstream of discharges from three large bleached kraft pulp and paper mills, and host community municipal sewage treatment plants (STP). After all three mills switched to elemental chlorine-free bleaching in the late 1990s, studies from 2001 to 2003 found that the pattern of reproductive impacts on white sucker populations measured in 1994 was not repeated. In addition, population estimates of white sucker from 2002 to 2003 using mark-recapture techniques found that densities and biomass were well within the range of those of a reference population, and of those reported in the literature for unimpacted populations. Detailed studies immediately above and below each mill/sewage treatment plant showed no evidence of reproductive effects. However, a clear pattern of eutrophication was noted, which increased cumulatively downstream below each mill/STP. PMID:20872897

Mower, Barry F; Munkittrick, Kelly R; McMaster, Mark E; Van Beneden, Rebecca J

2011-01-01

392

Effects of total dissolved gas supersaturated water on lethality and catalase activity of Chinese sucker (Myxocyprinus asiaticus Bleeker).  

PubMed

Total dissolved gas (TDG) supersaturation caused by dam sluicing can result in gas bubble trauma (GBT) in fish and threaten their survival. In the present study, Chinese suckers (Myxocyprinus asiaticus Bleeker) were exposed to TDG supersaturated water at levels ranging from 120% to 145% for 48 h. The median lethal concentration (LC(50)) and the median lethal time (LT(50)) were determined to evaluate acute lethal effects on Chinese suckers. The results showed that the LC(50) values of 4, 6, 8, and 10 h were 142%, 137%, 135%, and 130%, respectively. The LT(50) values were 3.2, 4.7, 7.8, 9.2, and 43.4 h, respectively, when TDG supersaturated levels were 145%, 140%, 135%, 130%, and 125%. Furthermore, the biological responses in Chinese suckers were studied by assaying the catalase (CAT) activities in gills and muscles at the supersaturation level of 140% within LT(50). The CAT activities in the gills and muscle tissues exhibited a regularity of a decrease after an increase. CAT activities in the muscles were increased significantly at 3/5LT(50) (P<0.05) and then came back to the normal level. However, there were no significant differences between the treatment group (TDG level of 140%) and the control group (TDG level of 100%) on CAT activities in the gills before 3/5LT(50) (P>0.05), but the activities were significantly lower than the normal level at 4/5LT(50) and LT(50) (P<0.05). PMID:23024046

Chen, Shi-chao; Liu, Xiao-qing; Jiang, Wen; Li, Ke-feng; Du, Jun; Shen, Dan-zhou; Gong, Quan

2012-10-01

393

Oil well pump driving unit  

Microsoft Academic Search

An oil well pumping apparatus which includes a submerged reciprocating pump mounted in a tubing arrangement communicating with the wellhead, a sucker rod string extending through the tubing arrangement and connected in driving relation with the pump, and a pumping tee and stuffing box arrangement mounted on the casing of the well at the wellhead and including a sealed drive

Gilbertson

1984-01-01

394

Oil well pump driving unit  

Microsoft Academic Search

An oil well pumping apparatus which includes a submerged reciprocating pump mounted in a tubing arrangement communicating with the well head, a sucker rod string extending through the tubing arrangement and connected in driving relation with the pump, and a pumping tee and stuffing box arrangement mounted on the casing of the well at the well head and including a

Gilbertson

1982-01-01

395

Reduced growth and survival of larval razorback sucker fed selenium-laden zooplankton  

USGS Publications Warehouse

Four groups of larval razorback sucker, an endangered fish, were exposed to selenium-laden zooplankton and survival, growth, and whole-body residues were measured. Studies were conducted with 5, 10, 24, and 28-day-old larvae fed zooplankton collected from six sites adjacent to the Green River, Utah. Water where zooplankton were collected had selenium concentrations ranging from <0.4 to 78 ??g/L, and concentrations in zooplankton ranged from 2.3 to 91 ??g/g dry weight. Static renewal tests were conducted for 20 to 25 days using reference water with selenium concentrations of <1.1 ??g/L. In all studies, 80-100% mortality occurred in 15-20 days. In the 28-day-old larvae, fish weight was significantly reduced 25% in larvae fed zooplankton containing 12 ??g/g selenium. Whole-body concentrations of selenium ranged from 3.7 to 14.3 ??g/g in fish fed zooplankton from the reference site (Sheppard Bottom pond 1) up to 94 ??g/g in fish fed zooplankton from North Roadside Pond. Limited information prior to the studies suggested that the Sheppard pond 1 site was relatively clean and suitable as a reference treatment; however, the nearly complete mortality of larvae and elevated concentrations of selenium in larvae and selenium and other elements in zooplankton indicated that this site was contaminated with selenium and other elements. Selenium concentrations in whole-body larvae and in zooplankton from all sites were close to or greater than toxic thresholds where adverse effects occur in fish. Delayed mortality occurred in larvae fed the two highest selenium concentrations in zooplankton and was thought due to an interaction with other elements. ?? 2004 Elsevier Inc. All rights reserved.

Hamilton, S. J.; Buhl, K. J.; Bullard, F. A.; McDonald, S. F.

2005-01-01

396

Physiological hepatic response to zinc oxide nanoparticle exposure in the white sucker, Catostomus commersonii.  

PubMed

Liver toxicity of commercially relevant zinc oxide nanoparticles (nZnO) was assessed in a benthic freshwater cypriniform, the white sucker (Catostomus commersonii). Exposure to nZnO caused several changes in levels of liver enzyme activity, antioxidants, and lipid peroxidation end products consistent with an oxidative stress response. Aconitase activity decreased by ~65% but tended to be restored to original levels upon supplementation with Fe(2+), indicating oxidative inactivation of the 4Fe-4S cluster. Furthermore, glucose-6-phosphate dehydrogenase activity decreased by ~29%, and glutathione levels increased by ~56%. Taken together, these suggest that nZnO induces hepatic physiological stress. Each assay was then validated by using a single liver homogenate or plasma sample that was partitioned and treated with nZnO or Zn(2+), the breakdown product of nZnO. It was found that Zn(2+), but not nZnO, increased detected glutathione reductase activity by ~14% and decreased detected malondialdehyde by ~39%. This indicates that if appreciable nZnO dissolution occurs in liver samples during processing and assay, it may skew results, with implications not only for this study, but also for a wide range of nanotoxicology studies focusing on nZnO. Finally, in vitro incubations of cell-free rat blood plasma with nZnO failed to generate any significant increase in malondialdehyde or protein carbonyl levels, or any significant decrease in ferric reducing ability of plasma. This suggests that at the level tested, any oxidative stress caused by nZnO is the result of a coordinated physiological response by the liver. PMID:24704545

Dieni, Christopher Anthony; Callaghan, Neal Ingraham; Gormley, Patrick Thomas; Butler, Kathryn Marie Alison; Maccormack, Tyson James

2014-05-01

397

21 CFR 876.4270 - Colostomy rod.  

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod is a device...

2014-04-01

398

21 CFR 876.4270 - Colostomy rod.  

Code of Federal Regulations, 2010 CFR

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod is a device...

2010-04-01

399

21 CFR 876.4270 - Colostomy rod.  

Code of Federal Regulations, 2012 CFR

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod is a device...

2012-04-01

400

21 CFR 876.4270 - Colostomy rod.  

Code of Federal Regulations, 2011 CFR

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod is a device...

2011-04-01

401

21 CFR 876.4270 - Colostomy rod.  

Code of Federal Regulations, 2013 CFR

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod is a device...

2013-04-01

402

Control rods in LMFBRs: a physics assessment  

SciTech Connect

This physics assessment is based on roughly 300 control rod worth measurements in ZPPR from 1972 to 1981. All ZPPR assemblies simulated mixed-oxide LMFBRs, representing sizes of 350, 700, and 900 MWe. Control rod worth measurements included single rods, various combinations of rods, and Ta and Eu rods. Additional measurements studied variations in B/sub 4/C enrichment, rod interaction effects, variations in rod geometry, neutron streaming in sodium-filled channels, and axial worth profiles. Analyses were done with design-equivalent methods, using ENDF/B Version IV data. Some computations for the sensitivities to approximations in the methods have been included. Comparisons of these analyses with the experiments have allowed the status of control rod physics in the US to be clearly defined.

McFarlane, H.F.; Collins, P.J.

1982-08-01

403

Metal concentration and calcification of bone of white sucker ( Catostomus commersoni ) in relation to lake pH  

Microsoft Academic Search

The concentrations of 17 elements were determined in the bone of white suckers (Catostomus commersoni) netted from 5 acid (pH range 4.8 to 5.8) and 2 circumneutral (pH=6.2 and 6.3) lakes in south-central Ontario. The bone Ca:P dry weight ratios were similar (2.0:1) for all fish populations except those of George Lake (pH=4.8) which showed a significantly lower Ca:P ratio

L. I. Bendell-Young; H. H. Harvey

1986-01-01

404

Distribution, Health, and Development of Larval and Juvenile Lost River and Shortnose Suckers in the Williamson River Delta Restoration Project and Upper Klamath Lake, Oregon: 2008 Annual Data Summary  

USGS Publications Warehouse

Federally endangered Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris were once abundant throughout their range but populations have declined; they have been extirpated from several lakes, and may no longer reproduce in others. Poor recruitment into the adult spawning populations is one of several reasons cited for the decline and lack of recovery of these species, and may be the consequence of high mortality during juvenile life stages. High larval and juvenile sucker mortality may be exacerbated by an insufficient quantity of suitable rearing habitat. Within Upper Klamath Lake, a lack of marshes also may allow larval suckers to be swept from suitable rearing areas downstream into the seasonally anoxic waters of the Keno Reservoir. The Nature Conservancy (TNC) flooded about 3,600 acres to the north of the Williamson River mouth (Tulana Unit) in October 2007, and about 1,400 acres to the south and east of the Williamson River mouth (Goose Bay Unit) a year later, to retain larval suckers in Upper Klamath Lake, create nursery habitat for suckers, and improve water quality. In collaboration with TNC, the Bureau of Reclamation, and Oregon State University, we began a long-term collaborative research and monitoring program in 2008 to assess the effects of the Williamson River Delta restoration on the early life-history stages of Lost River and shortnose suckers. Our approach includes two equally important aspects. One component is to describe habitat use and colonization processes by larval and juvenile suckers and non-sucker fish species. The second is to evaluate the effects of the restored habitat on the health and condition of juvenile suckers. This report contains a summary of the first year of data collected as a part of this monitoring effort.

Burdick, Summer M.; Ottinger, Christopher; Brown, Daniel T.; VanderKooi, Scott P.; Robertson, Laura; Iwanowicz, Deborah

2009-01-01

405

Solid-state-laser-rod holder  

DOEpatents

The disclosure relates to a solid state laser rod holder comprising Invar, copper tubing, and epoxy joints. Materials and coefficients of expansion of the components of the holder combine with the rod to produce a joint which will give before the rod itself will. The rod may be lased at about 70 to 80/sup 0/K and returned from such a temperature to room temperature repeatedly without its or the holder's destruction.

Gettemy, D.J.; Barnes, N.P.; Griggs, J.E.

1981-08-11

406

Filter for a drill string  

DOEpatents

A filter for a drill string comprises a perforated receptacle having an open end and a perforated end and first and second mounting surfaces are adjacent the open end. A transmission element is disposed within each of the first and second mounting surfaces. A capacitor may modify electrical characteristics of an LC circuit that comprises the transmission elements. The respective transmission elements are in communication with each other and with a transmission network integrated into the drill string. The transmission elements may be inductive couplers, direct electrical contacts, or optical couplers. In some embodiments of the present invention, the filter comprises an electronic component. The electronic component may be selected from the group consisting of a sensor, a router, a power source, a clock source, a repeater, and an amplifier.

Hall, David R. (Provo, UT); Pixton, David S. (Lehi, UT); Briscoe, Michael (Lehi, UT); McPherson, James (Sandy, UT)

2007-12-04

407

Topics in Open Topological Strings  

E-print Network

This thesis is based on some selected topics in open topological string theory which I have worked on during my Ph.D. It comprises an introductory part where I have focused on the points most needed for the later chapters, trading completeness for conciseness and clarity. Then, following [12], we discuss tadpole cancellation for topological strings where we mainly show how its implementation is needed for ensuring the same "odd" moduli decoupling encountered in the closed theory. Next we move to analyse how the open and closed effective field theories for the B model interact writing the complete Lagrangian. We first check it deriving some already known tree level amplitudes in term of target space quantities, and then we extend the recipe to new results; later we implement open closed duality from a target field theory perspective. This last subject is also analysed from a worldsheet point of view extending the analysis of [13]. Some ideas for future research are briefly reported.

Andrea Prudenziati

2010-10-16

408

Shape of cosmic string loops  

NASA Astrophysics Data System (ADS)

Complicated cosmic string loops will fragment until they reach simple, nonintersecting (“stable”) configurations. Through extensive numerical study we characterize these attractor loop shapes including their length, velocity, kink, and cusp distributions. We find that an initial loop containing M harmonic modes will, on average, split into 3M stable loops. These stable loops are approximately described by the degenerate kinky loop, which is planar and rectangular, independently of the number of modes on the initial loop. This is confirmed by an analytic construction of a stable family of perturbed degenerate kinky loops. The average stable loop is also found to have a 40% chance of containing a cusp. We examine the properties of stable loops of different lengths and find only slight variation. Finally we develop a new analytic scheme to explicitly solve the string constraint equations.

Copi, Craig J.; Vachaspati, Tanmay

2011-01-01

409

Resurgent Supersymmetry and String Theory  

E-print Network

We study a realization of accidental supersymmetry in type IIB string theory as a proof-of-principle of the mechanism and as a prototype of the strong sector present in resurgent supersymmetry, a warped UV-completion of natural supersymmetry. We first introduce the mechanism of accidental supersymmetry as a way of producing a supersymmetric spectrum in the IR of a quasi-conformal field theory, and then go on to discuss the utility of the mechanism in the specific BSM model of resurgent supersymmetry. The realization of accidental SUSY that we study is IIB string theory on an orbifold of the Klebanov-Strassler solution, and in doing so, argue that it is a noncompact example of accidental SUSY.

Brust, Christopher

2014-01-01

410

Bose-Einstein Condensate strings  

E-print Network

We consider the possible existence of gravitationally bound general relativistic strings consisting of Bose-Einstein Condensate (BEC) matter which is described, in the Newtonian limit, by the zero temperature time-dependent nonlinear Schr{\\"}odinger equation (the Gross-Pitaevskii equation), with repulsive inter-particle interactions. In the Madelung representation of the wave function, the quantum dynamics of the condensate can be formulated in terms of the classical continuity equation and the hydrodynamic Euler equations. In the case of a condensate with quartic nonlinearity, the condensates can be described as a gas with two pressure terms, the interaction pressure, which is proportional to the square of the matter density, and the quantum pressure, which is without any classical analogue though, when the number of particles in the system is high enough, the latter may be neglected. By assuming cylindrical symmetry, we analyze the physical properties of the BEC strings in both the interaction pressure and ...

Harko, Tiberiu

2014-01-01

411

Hydraulic Actuator for Ganged Control Rods  

NASA Technical Reports Server (NTRS)

Hydraulic actuator moves several nuclear-reactor control rods in unison. Electromagnetic pump pushes liquid lithium against ends of control rods, forcing them out of or into nuclear reactor. Color arrows show lithium flow for reactor startup and operation. Flow reversed for shutdown. Conceived for use aboard spacecraft, actuator principle applied to terrestrial hydraulic machinery involving motion of ganged rods.

Thompson, D. C.; Robey, R. M.

1986-01-01

412

49 CFR 236.793 - Rod, lock.  

Code of Federal Regulations, 2012 CFR

...APPLIANCES Definitions § 236.793 Rod, lock. A rod, attached to the front rod or lug of a switch, movable-point frog or derail, through which a locking plunger may extend when the switch points or derail are in the normal or reverse...

2012-10-01

413

49 CFR 236.793 - Rod, lock.  

Code of Federal Regulations, 2013 CFR

...APPLIANCES Definitions § 236.793 Rod, lock. A rod, attached to the front rod or lug of a switch, movable-point frog or derail, through which a locking plunger may extend when the switch points or derail are in the normal or reverse...

2013-10-01

414

49 CFR 236.793 - Rod, lock.  

Code of Federal Regulations, 2011 CFR

...APPLIANCES Definitions § 236.793 Rod, lock. A rod, attached to the front rod or lug of a switch, movable-point frog or derail, through which a locking plunger may extend when the switch points or derail are in the normal or reverse...

2011-10-01

415

49 CFR 236.793 - Rod, lock.  

Code of Federal Regulations, 2010 CFR

...APPLIANCES Definitions § 236.793 Rod, lock. A rod, attached to the front rod or lug of a switch, movable-point frog or derail, through which a locking plunger may extend when the switch points or derail are in the normal or reverse...

2010-10-01

416

Control rod support having planar wear surfaces  

SciTech Connect

This patent describes a combination. It comprises: a longitudinally extending rod guide; a support for a control rod. The support being positioned within the rod guide and intended to receive and minimize scarring of the control rod; a cylindrical control rod having a convex surface and being held by a spider including vanes. The support being relatively flat and thin, and having a predetermined exterior cross-sectional configuration and including a control rod opening formed in the support and having a predetermined configuration and cross-sectional area, a channel formed in the support to receive one of the vanes and communicate with the control rod opening. The channel forming a respective pair of junctures with the control rod opening. The control rod opening including a pair of planar wear surfaces, each parallel to the axis of the control rod opening and extending laterally from the respective junctures to afford a planar-to-convex interface between the convex surface of the control rod and the planar wear surfaces of the support when the convex surface of the control rod abuts.

Veronesi, L.; Schockling, L.A.

1990-02-20

417

Latch assembly for a control rod drive  

Microsoft Academic Search

This patent describes a control rod drive for positioning a control rod in a nuclear reactor vessel. It comprises: a shaft; a ballnut positioned over the shaft and being translatable upon rotation of the shaft; a piston disposed coaxially with the shaft and on the ballnut for positioning the control rod; means for selectively rotating the shaft in a first

Gibo

1992-01-01

418

Removable control rod drive shaft guide  

Microsoft Academic Search

A removable control rod drive shaft guide is described for a control rod ''guide'' structure card, comprising: a. a substantially annular shaped main body portion having a central axial bore for receiving a control rod drive shaft and an upper exterior groove for receiving removal tooling; b. the main body portion having a reduced outer diameter at its lower section;

M. W. Ales; S. K. Brown; L. D. Dixon

1988-01-01

419

Magnetic switch for reactor control rod  

Microsoft Academic Search

This patent describes a control rod system for a nuclear reactor utilizing an electromagnetic grapple mechanism for holding and releasing a control rod, the improvement comprising a magnetic reed switch assembly having a Curie-point magnetic shunt and responsive to reactor coolant temperature for short circuiting the electromagnetic grapple mechanism causing release of the control rod when the coolant temperature reaches

Germer

1986-01-01

420

INDICATION OF CONTROL-ROD POSITION  

Microsoft Academic Search

The following ways of indicating the position of control rods for a ; large power-producing reactor are discussed: position of each control-rod group ; at the control desk; position of each rod by means of individual indicators on a ; display panel; and a permanent printed record of all significant changes in group ; positions with the time of the

R. D. Bryden; K. J. Simm

1959-01-01

421

Reactor control rod timing system. [LMFBR  

Microsoft Academic Search

A fluid driven jet-edge whistle timing system is described for control rods of a nuclear reactor for producing real-time detection of the timing of each control rod in its scram operation. An important parameter in reactor safety, particularly for liquid metal fast breeder reactors (LMFBR), is the time deviation between the time the control rod is released and the time

P. T. K

1980-01-01

422

Cosmological Perturbations from Cosmic Strings  

E-print Network

Some aspects of the theory of cosmological perturbations from cosmic strings and other topological defects are outlined, with particular reference to a simple example: a spatially flat CDM-dominated universe. The conserved energy-momentum pseudo-tensor is introduced, and the equation for the density perturbation derived from it. It is shown how the scaling hypothesis for defect evolution results in a Harrison-Zel'dovich spectrum for wavelengths well inside the horizon.

Mark Hindmarsh

1994-12-20

423

Informing New String Programmes: Lessons Learned from an Australian Experience  

ERIC Educational Resources Information Center

Although there are many examples of notable string programmes there has been relatively little comparative analysis of these programmes. This paper examines three benchmark string programmes (The University of Illinois String Project, The Tower Hamlets String Teaching Project and Colourstrings) alongside Music4All, an innovative string programme…

Murphy, Fintan; Rickard, Nikki; Gill, Anneliese; Grimmett, Helen

2011-01-01

424

Magnetic strings in dilaton gravity  

SciTech Connect

First, I present two new classes of magnetic rotating solutions in four-dimensional Einstein-Maxwell-dilaton gravity with Liouville-type potential. The first class of solutions yields a four-dimensional spacetime with a longitudinal magnetic field generated by a static or spinning magnetic string. I find that these solutions have no curvature singularity and no horizons, but have a conic geometry. In these spacetimes, when the rotation parameter does not vanish, there exists an electric field, and therefore the spinning string has a net electric charge which is proportional to the rotation parameter. The second class of solutions yields a spacetime with an angular magnetic field. These solutions have no curvature singularity, no horizon, and no conical singularity. The net electric charge of the strings in these spacetimes is proportional to their velocities. Second, I obtain the (n+1)-dimensional rotating solutions in Einstein-dilaton gravity with Liouville-type potential. I argue that these solutions can present horizonless spacetimes with conic singularity, if one chooses the parameters of the solutions suitable. I also use the counterterm method and compute the conserved quantities of these spacetimes.

Dehghani, M.H. [Physics Department and Biruni Observatory, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Research Institute for Astrophysics and Astronomy of Maragha (RIAAM), Maragha (Iran, Islamic Republic of)

2005-03-15

425

Cosmological Consequences of String Axions  

SciTech Connect

Axion fluctuations generated during inflation lead to isocurvature and non-Gaussian temperature fluctuations in the cosmic microwave background radiation. Following a previous analysis for the model independent string axion we consider the consequences of a measurement of these fluctuations for two additional string axions. We do so independent of any cosmological assumptions except for the axions being massless during inflation. The first axion has been shown to solve the strong CP problem for most compactifications of the heterotic string while the second axion, which does not solve the strong CP problem, obeys a mass formula which is independent of the axion scale. We find that if gravitational waves interpreted as arising from inflation are observed by the PLANCK polarimetry experiment with a Hubble constant during inflation of H{sub inf} {approx}> 10{sup 13} GeV the existence of the first axion is ruled out and the second axion cannot obey the scale independent mass formula. In an appendix we quantitatively justify the often held assumption that temperature corrections to the zero temperature QCD axion mass may be ignored for temperatures T {approx}< {Lambda}{sub QCD}.

Kain, Ben

2005-12-15

426

Nuclear Force from String Theory  

E-print Network

We compute nuclear force in a holographic model of QCD on the basis of a D4-D8 brane configuration in type IIA string theory. Repulsive core of nucleons is quite important in nuclear physics, but its origin has not been well-understood in strongly-coupled QCD. We find that string theory via gauge/string duality deduces this repulsive core at short distance between nucleons. Since baryons in the model are realized as solitons given by Yang-Mills instanton configuration on flavor D8-branes, ADHM construction of two instantons probes well the nucleon interaction at short scale, which provides the nuclear force quantitatively. We obtain, as well as a tensor force, a central force which is strongly repulsive as suggested in experiments and lattice results. In particular, the nucleon-nucleon potential V(r) (as a function of the distance) scales as 1/r^2, which is peculiar to the holographic model. We compare our results with one-boson exchange model using the nucleon-nucleon-meson coupling obtained in our previous paper (arXiv:0806.3122).

Koji Hashimoto; Tadakatsu Sakai; Shigeki Sugimoto

2009-01-28

427

The Lineage of String Theory  

E-print Network

The Regge trajectories, upon which string theory is based, behave as rigid rotators rather than vibrating strings. The same relation, between the angular momentum, and the square of the mass, can be found in gravity, the electroweak, and strong interactions. The angle deficit for cosmic strings is shown to be an angle excess that is related to the increase of the circumference of a uniformly rotating disc. Schr\\"odinger's time independent equation with a centrifugal barrier gives an automorphic function that can be constructed as the ratio of its two independent solutions for values of the angular momentum lying outside of their positive, integer values. If the fixed points 0 and $\\infty$ in the z-plane correspond to $-i$ and $+i$ in the $\\omega$-plane, then elliptic substitutions tessellate the $\\omega$-plane in the form of cresents, while if the fixed points correspond to -1 and +1 in the $\\omega$-plane are source and sink, just like the lines of force between positive and negative charges. The unit disc undergoes a stretching by a Lorentz transform.

B. H. Lavenda

2011-10-22

428

QCD String formation and the Casimir Energy  

E-print Network

Three distinct scales are identified in the excitation spectrum of the gluon field around a static quark-antiquark pair as the color source separation R is varied. The spectrum, with string-like excitations on the largest length scales of 2-3 fm, provides clues in its rich fine structure for developing an effective bosonic string description. New results are reported from the three-dimensional Z(2) and SU(2) gauge models, providing further insight into the mechanism of bosonic string formation. The precocious onset of string-like behavior in the Casimir energy of the static quark-antiquark ground state is observed below R=1 fm where most of the string eigenmodes do not exist and the few stable excitations above the ground state are displaced. We find no firm theoretical foundation for the widely held view of discovering string formation from high precision ground state properties below the 1 fm scale.

K. Jimmy Juge; J. Kuti; C. Morningstar

2004-01-27

429

Big Bang Models in String Theory  

E-print Network

These proceedings are based on lectures delivered at the "RTN Winter School on Strings, Supergravity and Gauge Theories", CERN, January 16 - January 20, 2006. The school was mainly aimed at Ph.D. students and young postdocs. The lectures start with a brief introduction to spacetime singularities and the string theory resolution of certain static singularities. Then they discuss attempts to resolve cosmological singularities in string theory, mainly focusing on two specific examples: the Milne orbifold and the matrix big bang.

Ben Craps

2006-05-19

430

String webs and 1 4 BPS monopoles  

Microsoft Academic Search

We argue for the existence of many new 14 BPS states in N = 4 SU(Nc) Super-Yang-Mills theory with Nc ? 3, by constructing them from supersymmetric string webs whose external strings terminate on parallel D3-branes. The masses of the string webs are shown to agree with the BPS bound for the corresponding states in SYM. We identify the curves

Oren Bergman; Barak Kol

1998-01-01

431

Gamma Ray Bursts from Ordinary Cosmic Strings  

E-print Network

We give an upper estimate for the number of gamma ray bursts from ordinary (non-superconducting) cosmic strings expected to be observed at terrestrial detectors. Assuming that cusp annihilation is the mechanism responsible for the bursts we consider strings arising at a GUT phase transition and compare our estimate with the recent BATSE results. Further we give a lower limit for the effective area of future detectors designed to detect the cosmic string induced flux of gamma ray bursts.

R. H. Brandenberger; A. T. Sornborger; M. Trodden

1993-02-12

432

Exact solutions and singularities in string theory  

SciTech Connect

We construct two new classes of exact solutions to string theory which are not of the standard plane wave of gauged WZW type. Many of these solutions have curvature singularities. The first class includes the fundamental string solution, for which the string coupling vanishes near the singularity. This suggests that the singularity may not be removed by quantum corrections. The second class consists of hybrids of plane wave and gauged WZW solutions. We discuss a four-dimensional example in detail.

Horowitz, G.T. (Isaac Newton Institute, Cambridge CB3 0EH (United Kingdom)); Tseytlin, A.A. (Theoretical Physics Group, Blackett Laboratory Imperial College, London SW7 2BZ (United Kingdom))

1994-10-15

433

String Fragmentation Model in Space Radiation Problems  

NASA Technical Reports Server (NTRS)

String fragmentation models such as the Lund Model fit experimental particle production cross sections very well in the high-energy limit. This paper gives an introduction of the massless relativistic string in the Lund Model and shows how it can be modified with a simple assumption to produce formulas for meson production cross sections for space radiation research. The results of the string model are compared with inclusive pion production data from proton-proton collision experiments.

Tang, Alfred; Johnson, Eloise (Editor); Norbury, John W.; Tripathi, R. K.

2002-01-01

434

Orbifold SUSY GUT from the Heterotic String  

SciTech Connect

From the string partition function, we discuss the mass-shell and GSO projection conditions valid for Kaluza-Klein (KK) as well as massless states in the heterotic string theory compactifled on a nonprime orbifold. Using the obtained conditions we construct a 4D string standard model, which is embedded in a 6D SUSY GUT by including KK states above the compactiflcation scale. We discuss the stringy threshold corrections to gauge couplings, including the Wilson line effects.

Kyae, Bumseok [Department of Physics and Astronomy and Center for Theoretical Physics, Seoul National University, Seoul 151-747 (Korea, Republic of)

2008-11-23

435

Cosmological String Theory with Thermal Energy  

E-print Network

An attempt to construct a cosmological scenario directly from string theory is made. Cosmological string theory was presented by Antoniadis, Bachas, Ellis and Nanopoulos. They also expect loop effects on cosmological string theory. In this paper, we point out the other importance of the one-loop effect, the finite temperature effect. The equations of motion for background geometry at finite temperature are given. We address a problem on derivation of the effective action at nonzero temperature.

Kiyoshi Shiraishi

2013-11-24

436

String theory: big problem for small size  

E-print Network

String theory is the most promising candidate theory for a unified description of all fundamental forces exist in the nature. It provides a mathematical framework that combine quantum theory with Einstein's general theory of relativity. But due to the extremely small size of strings, nobody has been able to detect it directly in the laboratory till today. In this article, we have presented a general introduction to string theory.

S. Sahoo

2012-09-25

437

String junction as a baryonic constituent  

NASA Astrophysics Data System (ADS)

We extend the model for QCD string with quarks to consider the Mercedes Benz string configuration describing the three-quark baryon. Under the assumption of adiabatic separation of quark and string junction motion we formulate and solve the classical equation of motion for the junction. We dare to quantize the motion of the junction, and discuss the impact of these modes on the baryon spectra.

Kalashnikova, Yu. S.; Nefediev, A. V.

1996-02-01

438

Generating Functional in String Field Theory  

E-print Network

In our paper, we introduce a path integral of general functional field in order to build the path integral formalism in string field theory from the fact that a string field is a functional field, and describe a method for calculating it in the case of "Gauss-type". We also obtain the generating functional of an open bosonic string and the corresponding Feynman diagram.

Am-Gil Ri; Tae-Song Kim; Song-Jin Im

2013-11-23

439

Geometry and Topology of String Junctions  

E-print Network

We study elliptic fibrations by analyzing suitable deformations of the fibrations and vanishing cycles. We introduce geometric string junctions and describe some of their properties. We show how the structure of the geometric string junctions is naturally related to the Lie algebra structures of the associated singularities. One application in physics is in F-theory, where our novel approach connecting deformations and Lie algebras describes the structure of generalized type IIB seven-branes and string junction states which end on them.

Grassi, Antonella; Shaneson, Julius L

2014-01-01

440

p-adic string theories provide lattice Discretization to the ordinary string worldsheet.  

PubMed

A class of models called p-adic strings is useful in understanding the tachyonic instability of string theory. These are found to be empirically related to the ordinary strings in the p-->1 limit. We propose that these models provide discretization for the string worldsheet and argue that the limit is naturally thought of as a continuum limit in the sense of the renormalization group. PMID:17155316

Ghoshal, Debashis

2006-10-13

441

Rod cluster having improved vane configuration  

SciTech Connect

This patent describes a pressurized water reactor vessel, the vessel defining a predetermined axial direction of the flow of coolant therewithin and having plural spider assemblies supporting, for vertical movement within the vessel, respective clusters of rods in spaced, parallel axial relationship, parallel to the predetermined axial direction of coolant flow, and a rod guide for each spider assembly and respective cluster of rods. The rod guide having horizontally oriented support plates therewithin, each plate having an interior opening for accommodating axial movement therethrough of the spider assembly and respective cluster of rods. The opening defining plural radially extending channels and corresponding parallel interior wall surfaces of the support plate.

Shockling, L.A.; Francis, T.A.

1989-09-05

442

Nuclear reactor remote disconnect control rod coupling indicator  

Microsoft Academic Search

A coupling indicator for use with nuclear reactor control rod assemblies which have remotely disengageable couplings between the control rod and the control rod drive shaft is described. The coupling indicator indicates whether the control rod and the control rod drive shaft are engaged or disengaged. A resistive network, utilizing magnetic reed switches, senses the position of the control rod

Vuckovich

1977-01-01

443

Nuclear reactor remote disconnect control rod coupling indicator  

Microsoft Academic Search

A coupling indicator for use with nuclear reactor control rod assemblies which have remotely disengageable couplings between the control rod and the control rod drive shaft. The coupling indicator indicates whether the control rod and the control rod drive shaft are engaged or disengaged. A resistive network, utilizing magnetic reed switches, senses the position of the control rod drive mechanism

Vuckovich

1977-01-01

444

Utility of the TBARS assay in detecting oxidative stress in white sucker (Catostomus commersoni) populations exposed to pulp mill effluent.  

PubMed

Recent evidence indicates that contaminant-stimulated free radical production and resulting oxidative damage may be an important mechanism of toxicity in organisms exposed to water-borne contaminants. This study tested the hypothesis that increases in oxidative stress and associated biochemical alterations would be present in white sucker (Catostomus commersoni) living in an environment receiving pulp mill effluent. Consistent increases in liver TBARS and frequent increases in gonadal TBARS were observed immediately downstream of the pulp mill effluent discharge; observable effects were attenuated with distance until they were not significantly different from reference values. Increases detected with the TBARS assay were commensurate with increases detected using the lipid hydroperoxides assay, a mechanistically independent technique. Fish exposed to pulp mill effluent also exhibited significant increases in hepatic free iron and ascorbic acid and a reduced free radical scavenging capacity in the livers of fish downstream of the effluent discharge relative to reference fish. Increases in oxidative stress are not necessarily dependent on increases in lipid substrate or related to reductions in ascorbic acid. TBARS values similar to those observed in fish resident below pulp mill effluent discharges were observed in white sucker 2 h after intraperitoneal injection using 15 mg/kg body weight ferric nitrilotriacetate (Fe(3+) NTA) as a positive control. This study indicates oxidative stress could be a mechanism of toxicity in fish exposed to pulp mill effluent and demonstrates the utility of TBARS in delineating zones of exposure to pulp mill effluent. PMID:12758008

Oakes, Ken D; Van Der Kraak, Glen J

2003-05-29

445

Ecology of bonytail and razorback sucker and the role of off-channel habitats in their recovery  

USGS Publications Warehouse

The bonytail and razorback sucker are two of four endangered mainstem fishes found in the Colorado River. Unlike the Colorado pikeminnow and humpback chub, wild populations of the bonytail and razorback sucker are either extirpated from the mainstem river or are nearly so. Agencies are aggressively stocking these fish wile repatriated fish spawn, their young are rapidly eaten by introduced predators. A decade of predator removal efforts has proved ineffective in restoring natural recruitment. Today, the presence of these species is totally dependent on stocking, suggesting both species are worse off today than when recovery efforts began nearly two decades ago. In contrast, both species readily produce young in ponds where nonnative predators are absent. Evidence shows they evolved with the ability to spawn in both flowing and standing water, which suggests isolated oxbow communities may be been an essential feature in their evolution and survival strategy. Sustainable populations during the past few decades have only occurred in isolated ponds devoid of predatory nonnative fish. Efforts to force recovery in the main channel river continue to fail due to the presence of nonnative predators that may be economically important recreational species. Off-channel sanctuaries provide research and management opportunities on a scale that are both biologically and economically realistic. Effective management of these species in small habitats appears to be the most logical approach to advance recovery in larger river reachesa?|

Mueller, Gordon A.

2006-01-01

446

Exploiting rod technology. Final report  

SciTech Connect

ROD development was proceeding apace until recent budgetary decisions caused funding support for ROD development to be drastically reduced. The funding which was originally provided by DARPA and the Balanced Technology Initiative (BTI) Office has been cut back to zero from $800K. To determine the aeroballistic coefficients of a candidate dart, ARDEC is currently supporting development out of its own 6.2 funds at about $100K. ARDEC has made slow progress toward achieving this end because of failures in the original dart during testing. It appears that the next dart design to be tested will diverge from the original concept visualized by DARPA and Science and Technology Associates (STA). STA, the design engineer, takes exception to these changes on the basis of inappropriate test conditions and insufficient testing. At this time, the full resolution of this issue will be difficult because of the current management structure, which separates the developer (ARDEC) from the designer (STA).

NONE

1990-06-01

447

The effective theory of long strings  

NASA Astrophysics Data System (ADS)

We present the low-energy effective theory on long strings in quantum field theory, including a streamlined review of previous literature on the subject. Such long strings can appear in the form of solitonic strings, as in the 4d Abelian Higgs model, or in the form of confining strings, as in Yang-Mills theories. The bottom line is that upon expanding in powers of 1 /L the energy levels of long (closed) strings (where L is the length of the string), all the terms up to (and including) order 1 /L 5 are universal. We argue that for excited strings in D > 3 space-time dimensions there is a universal deviation at order 1 /L 5 from the naive formula that is usually used to fit lattice results. For D = 3 this naive formula is valid even at order 1 /L 5. At order 1 /L 7 non-universal terms generically appear in all cases. We explain the physical origin of these results, and illuminate them in three different formulations of the effective action of long strings (the relationships among which we partly clarify). In addition, we corroborate these results by an explicit computation of the effective action on long strings in confining theories which have a gravitational dual. These predictions can be tested by precise simulations of 4d Yang-Mills theory on the lattice.

Aharony, Ofer; Komargodski, Zohar

2013-05-01

448

Minimal string theories and integrable hierarchies  

NASA Astrophysics Data System (ADS)

Well-defined, non-perturbative formulations of the physics of string theories in specific minimal or superminimal model backgrounds can be obtained by solving matrix models in the double scaling limit. They provide us with the first examples of completely solvable string theories. Despite being relatively simple compared to higher dimensional critical string theories, they furnish non-perturbative descriptions of interesting physical phenomena such as geometrical transitions between D-branes and fluxes, tachyon condensation and holography. The physics of these theories in the minimal model backgrounds is succinctly encoded in a non-linear differential equation known as the string equation, along with an associated hierarchy of integrable partial differential equations (PDEs). The bosonic string in (2,2m-1) conformal minimal model backgrounds and the type 0A string in (2,4 m) superconformal minimal model backgrounds have the Korteweg-de Vries system, while type 0B in (2,4m) backgrounds has the Zakharov-Shabat system. The integrable PDE hierarchy governs flows between backgrounds with different m. In this thesis, we explore this interesting connection between minimal string theories and integrable hierarchies further. We uncover the remarkable role that an infinite hierarchy of non-linear differential equations plays in organizing and connecting certain minimal string theories non-perturbatively. We are able to embed the type 0A and 0B (A,A) minimal string theories into this single framework. The string theories arise as special limits of a rich system of equations underpinned by an integrable system known as the dispersive water wave hierarchy. We find that there are several other string-like limits of the system, and conjecture that some of them are type IIA and IIB (A,D) minimal string backgrounds. We explain how these and several other string-like special points arise and are connected. In some cases, the framework endows the theories with a non-perturbative definition for the first time. Notably, we discover that the Painleve IV equation plays a key role in organizing the string theory physics, joining its siblings, Painleve I and II, whose roles have previously been identified in this minimal string context. We then present evidence that the conjectured type II theories have smooth non-perturbative solutions, connecting two perturbative asymptotic regimes, in a 't Hooft limit. Our technique also demonstrates evidence for new minimal string theories that are not apparent in a perturbative analysis.

Iyer, Ramakrishnan

449

S-duality in String Gas Cosmology  

E-print Network

We consider a toy cosmological model in string theory involving the winding and momentum modes of (m,n) strings, i.e. bound states of m fundamental and n D-strings. The model is invariant under S-duality provided that m and n are interchanged. The dilaton is naturally stabilized due to S-duality invariance, which offers a new mechanism of moduli fixing in string gas cosmology. Using a tachyon field rolling down to its ground state, we also point out a possible way of realizing a cosmological phase with decreasing Hubble radius and constant dilaton.

S. Arapoglu; A. Karakci; A. Kaya

2006-11-17

450

Bell's Inequalities, Superquantum Correlations, and String Theory  

E-print Network

We offer an interpretation of super-quantum correlations in terms of a "doubly" quantum theory. We argue that string theory, viewed as a quantum theory with two deformation parameters, the string tension \\alpha' and the string coupling constant g_s, is such a super-quantum theory, one that transgresses the usual quantum violations of Bell's inequalities. We also discuss the \\hbar\\to\\infty limit of quantum mechanics in this context. As a super-quantum theory, string theory should display distinct experimentally observable super-correlations of entangled stringy states.

Lay Nam Chang; Zachary Lewis; Djordje Minic; Tatsu Takeuchi; Chia-Hsiung Tze

2011-04-17

451

Hosotani model in closed-string theory  

E-print Network

The Hosotani mechanism in the closed-string theory with current algebra symmetry is described by the (old covariant) operator method. We compare the gauge symmetry breaking mechanism in a string theory which contains SU(2) symmetry originated from current algebra with the one in an equivalent compactified closed-string theory. We also investigate the difference between the Hosotani mechanism and the Higgs mechanism in closed-string theories by calculation of a four-point amplitude of `Higgs' bosons at tree level.

Kiyoshi Shiraishi

2013-07-12

452

Spontaneous knotting of an agitated string.  

PubMed

It is well known that a jostled string tends to become knotted; yet the factors governing the "spontaneous" formation of various knots are unclear. We performed experiments in which a string was tumbled inside a box and found that complex knots often form within seconds. We used mathematical knot theory to analyze the knots. Above a critical string length, the probability P of knotting at first increased sharply with length but then saturated below 100%. This behavior differs from that of mathematical self-avoiding random walks, where P has been proven to approach 100%. Finite agitation time and jamming of the string due to its stiffness result in lower probability, but P approaches 100% with long, flexible strings. We analyzed the knots by calculating their Jones polynomials via computer analysis of digital photos of the string. Remarkably, almost all were identified as prime knots: 120 different types, having minimum crossing numbers up to 11, were observed in 3,415 trials. All prime knots with up to seven crossings were observed. The relative probability of forming a knot decreased exponentially with minimum crossing number and Möbius energy, mathematical measures of knot complexity. Based on the observation that long, stiff strings tend to form a coiled structure when confined, we propose a simple model to describe the knot formation based on random "braid moves" of the string end. Our model can qualitatively account for the observed distribution of knots and dependence on agitation time and string length. PMID:17911269

Raymer, Dorian M; Smith, Douglas E

2007-10-16

453

Fuel rod assembly to manifold attachment  

DOEpatents

A fuel element is formed with a plurality of fuel rod assemblies detachably connected to an overhead support with each of the fuel rod assemblies having a gas tight seal with the support to allow internal fission gaseous products to flow without leakage from the fuel rod assemblies into a vent manifold passageway system on the support. The upper ends of the fuel rod assemblies are located at vertically extending openings in the support and upper threaded members are threaded to the fuel rod assemblies to connect the latter to the support. The preferred threaded members are cap nuts having a dome wall encircling an upper threaded end on the fuel rod assembly and having an upper sealing surface for sealing contact with the support. Another and lower seal is achieved by abutting a sealing surface on each fuel rod assembly with the support. A deformable portion on the cap nut locks the latter against inadvertent turning off the fuel rod assembly. Orienting means on the fuel rod and support primarily locates the fuel rods azimuthally for reception of a deforming tool for the cap nut. A cross port in the fuel rod end plug discharges into a sealed annulus within the support, which serves as a circumferential chamber, connecting the manifold gas passageways in the support.

Donck, Harry A. (San Diego, CA); Veca, Anthony R. (San Diego, CA); Snyder, Jr., Harold J. (San Diego, CA)

1980-01-01

454

SCT Busy Flow Individual ROD  

E-print Network

SCT Busy Flow BUSY Module LTP 1 (wire-or) Crate 1-1 Crate 1-2 O/C TTL O/C TTL NIM 16 Individual ROD Module Out NIM O/C TTL CTP Link Global ATLAS Signals & Overall SCT Busy LVDS LVDS LTP 2 O/C TTL NIM NIM LVDS LTP 3 Local Busy O/C TTL NIM NIM LVDS in out LTP 4 O/C TTL NIM NIM LVDS Local Busyin out Local

University College London

455

Finding Optimal Alignment and Consensus of Circular Strings  

E-print Network

Finding Optimal Alignment and Consensus of Circular Strings T. Lee*, J.C. Na, H. Park, K. Park combinatorial algorithm for 3 strings ­ Sze et al. showed a condition for the existence of string whose radius

Lonardi, Stefano

456

8.251 String Theory for Undergraduates, Spring 2005  

E-print Network

Introduction to the main concepts of string theory to undergraduates. Since string theory is quantum mechanics of a relativistic string, the foundations of the subject can be explained to students exposed to both special ...

Zwiebach, Barton

457

8.251 String Theory for Undergraduates, Spring 2003  

E-print Network

Introduction to the main concepts of string theory to undergraduates. Since string theory is quantum mechanics of a relativistic string, the foundations of the subject can be explained to students exposed to both special ...

Zwiebach, Barton

458

CYP1A Induction and Blue Sac Disease in Early Life Stages of White Suckers (Catostomus commersoni) Exposed to Oil Sands  

Microsoft Academic Search

The objectives of this study were to evaluate the influence of natural oil sands on the early developmental stages of white sucker (Catostomus commersoni) and to determine whether biochemical responses in this species were similar to native fish caught in the Athabasca Oil Sands area. Early life stage (ELS) sediment toxicity tests were conducted using controls, reference sediments, natural oil

Maria V. Colavecchia; Peter V. Hodson; Joanne L. Parrott

2006-01-01

459

Responses of white sucker ( Catostomus commersoni) to 20 years of process and waste treatment changes at a bleached kraft pulp mill, and to mill shutdown  

Microsoft Academic Search

The impacts of pulp mill effluents on white sucker (Catostomus commersoni) have been studied at Jackfish Bay, ON, Canada since the late 1980s. The site receives effluent from a large bleached kraft pulp mill which is the only source of chemical contamination in the area. Many laboratory studies have looked at the toxicological consequences of pulping process changes, but the

L. K. Bowron; K. R. Munkittrick; M. E. McMaster; G. Tetreault; L. M. Hewitt

2009-01-01

460

A NOTE ON THE FREEZING-POINTS OF THE URINES OF TWO FRESH-WATER FISHES: THE CATFISH (AMEIURUS NEBULOSUS@ AND THE SUCKER (CATOSTOMUS COMMERSONI1)  

Microsoft Academic Search

In his book, Osmotic Regulation in Aquatic Animals, Krogh (1939) comments on the scarcity of available data for the osmotic concentra tion of the urines of fresh-water fishes. Since such data are appar ently not available for two of our common local forms, the catfish (Ameiurus nebulosus) and the sucker (Catostomus commersonii), we have been interested to make freezing-point determinations

CHARLOTTE HAYWOOD; MARY JEANNE CLAPP

461

Population Characteristics and Contaminant Burdens of the White Sucker ( Catostomus commersoni) from the St. Lawrence River near Cornwall, Ontario and Massena, New York  

Microsoft Academic Search

The objective of this study was to compare ecological and chemical characteristics of two populations of white sucker (Catostomus commersoni) (n = 762) upstream and downstream of the Moses-Saunders power dam in the St. Lawrence River. The downstream section of the St. Lawrence River near Cornwall, Ontario and Massena, New York is an International Joint Commission Area of Concern (AOC).

Lara L. Ridgway; François Chapleau; Michael E. Comba; Sean M. Backus

1999-01-01

462

Timing of spawning and assessment of a degree-day model to predict the in situ embryonic developmental rate of white sucker, Catostomus commersoni  

Microsoft Academic Search

We sampled eggs and larvae of white sucker, Catostomus commersoni , on six spawning grounds to (i) determine the influence of water temperature and discharge on spawning and (ii) assess the reliability of four degree-day equations developed to predict the attainment of organogenesis, eyed egg, hatching, and swim-up phases. We estimated a threshold temperature for spawning of 13°C at four

Patrice Hamel; Pierre Magnan; Michèle Lapointe; Pierre East

1997-01-01

463

Health of white sucker within the St. Louis River area of concern associated with habitat usage as assessed using stable isotopes  

USGS Publications Warehouse

In Spring 2011, 200 adult white sucker were collected in four areas of the St. Louis River area of concern (AOC), located in Minnesota and Wisconsin, USA. The areas included the upper AOC as a reference area, the upper estuary, St. Louis Bay and Superior Bay. Grossly visible abnormalities were documented and preserved for microscopic analyses, as were five to eight representative pieces of liver tissue. A piece of dorsal muscle was preserved for stable isotope analyses and otoliths removed for age determination. The incidence of raised skin lesions (mucoid plaques) was high (31 %), however, microscopically only 4.5 % of the white suckers had neoplasia (papillomas). The remaining lesions were epidermal hyperplasia. Superior Bay had the lowest percentage of skin/lip lesions (10 %), while St. Louis Bay had the highest (44 %). St. Louis Bay also had the highest incidence of skin neoplasms (12 %). No hepatocellular neoplasms were documented, however bile duct tumors were observed in 4.5 % of the suckers. Foci of cellular alteration were observed in fish from all sites except the upper AOC. Stable isotope data indicated that most of the suckers relied on the St. Louis River AOC for the majority (>75 %) of their diet, indicating they were resident within the AOC and not in Lake Superior. The amount of diet obtained from the upper estuary was a significant predictor of skin lesion incidence. Hence, habitat use within the AOC appears to be an important risk factor for skin and possibly, liver lesions.

Blazer, V. S.; Hoffman, J.; Walsh, H. L.; Braham, R. P.; Hahn, C.; Collins, P.; Jorgenson, Z.; Ledder, T.

2014-01-01

464

Health of white sucker within the St. Louis River area of concern associated with habitat usage as assessed using stable isotopes  

EPA Science Inventory

In Spring 2011, 200 adult white sucker were collected in four areas of the St. Louis River Area of Concern (AOC), located in Minnesota and Wisconsin, USA. The areas included the upper AOC as a reference area, the upper estuary, St. Louis Bay and Superior Bay. Grossly visible abno...

465

Spatial and temporal use of a spawning site in the middle green river by wild and hatchery-reared razorback suckers  

USGS Publications Warehouse

The population of endangered razorback suckers Xyrauchen texanus in the middle Green River (upper Colorado River basin) has declined during the last 40 years. The apparent cause for this decline is a lack of successful recruitment. This study used radiotelemetry to evaluate the ability of hatchery-reared razorback suckers to locate spawning areas where wild fish congregate during the ascending hydrographic limb of the snowmelt runoff. Hatchery-reared razorback suckers appeared to show similar reproductive behavior to wild fish. Both wild and hatchery-reared fish were found near the middle Green River spawning area between 1 and 25 May 2000. Hatchery fish occupied the same areas on the spawning site as wild fish, and remained on the spawning site during both nocturnal and diurnal hours. Males were more abundant on the spawning area than females, but the few females captured tended to stage away from the primary spawning area. The results from this study suggest hatchery-reared fish are capable of responding to natural cues that prompt spawning aggregations and are successful in locating existing spawning aggregations of wild fish. Given attention to stocking criteria, including genetic diversity and the size and time of stocking, the challenges of recovering razorback suckers will center on those factors that led to the population declines, particularly the survival of early life stages in off-channel habitats. ?? American Fisheries Society 2005.

Modde, T.; Bowen, Z.H.; Kitcheyan, D.C.

2005-01-01

466

Bosonic and Baryonic String Theory in Quantum Chromodynamics  

SciTech Connect

Bosonic string formation in gauge theories is reviewed with particular attention to the confining flux in lattice QCD and its effective string theory description. Recent results on the Casimir energy of the ground state and the string excitation spectrum are analyzed in the Dirichlet string limit of large separation between static sources. The closed string-soliton (torelon) with electric flux winding around a compact dimension is discussed and a new bound state tower spectrum at baryon string junctions is presented.

Kuti, Julius [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States)

2007-02-27

467

Patterns of Larval Sucker Emigration from the Sprague and Lower Williamson Rivers of the Upper Klamath Basin, Oregon, Prior to the Removal of Chiloquin Dam - 2006 Annual Report  

USGS Publications Warehouse

In 2006, we collected larval Lost River sucker Deltistes luxatus (LRS), shortnose sucker Chasmistes brevirostris (SNS), and Klamath largescale sucker Catostomus snyderi (KLS) emigrating from spawning areas in the Williamson and Sprague Rivers. This work is part of a multi-year effort to characterize the relative abundance, drift timing, and length frequencies of larval suckers in this watershed prior to the removal of Chiloquin Dam on the lower Sprague River. Additional larval drift samples were collected from the Fremont Bridge on Lakeshore Drive on the south end of Upper Klamath Lake near its outlet to the Link River. Because of difficulties in distinguishing KLS larvae from SNS larvae, individuals identified as either of these two species were grouped together and reported as KLS-SNS in this report. We found that larval densities varied by site with the highest densities being collected at the most upstream site on the Sprague River at river kilometer (rkm) 108.0 near Beatty, Oregon (Beatty), and the most downstream sites near Chiloquin, Oregon; one site on the Sprague River at rkm 0.7 (Chiloquin) and the other site on the Williamson River at rkm 7.4 (Williamson). Larval catches were relatively small and sporadic at two other sites on the Sprague River located between Chiloquin and Beatty (Power Station at rkm 9.5 and Lone Pine at rkm 52.7) and one site on the Sycan River at rkm 4.7. Most larvae (79 percent) collected in 2006 were identified as LRS. More larvae and eggs were collected at Chiloquin than at any other site. The seasonal timing of larval drift varied by location; larvae generally were captured earlier at upstream sites than at downstream sites. Cumulative catch percentages of drifting larvae suggest that larval LRS emigrated earlier than KLS-SNS larvae at every site. Drift of LRS larvae at Beatty began 3 to 4 weeks earlier than at Chiloquin or Williamson. At Chiloquin, peak larval catches occurred 3 and 5 weeks after peak egg catches. The daily peak in larval drift at Chiloquin occurred approximately 1.5 to 2.0 hours after sunset. Nightly peak larval drift varied by location; larvae were captured earlier in the evening at sites closer to known spawning locations than sites farther away from these areas. The highest numerical catches of sucker-sized eggs were at Chiloquin indicating that this site is in close proximity to a spawning area. Numerical catches of older, more developed larval and juvenile suckers also were highest at Chiloquin. This may be due to the turbulent nature of this site, which could have swept larger fish into the drift. Proportional catches of older, more developed larval and juvenile suckers were highest at Sycan, Lone Pine, Power Station, and Fremont Bridge. This indicates these sites are located nearer to sucker nursery areas rather than spawning areas. Very few larval LRS were collected at Fremont Bridge at the south end of Upper Klamath Lake. Larval KLS-SNS densities at Fremont Bridge were the third highest of the seven sampling sites. Peak drift of larval KLS-SNS at Fremont Bridge occurred the week after peak drift of larval KLS-SNS at Williamson. Although inter-annual variation continues to appear in the larval drift data, our results continue to show consistent patterns of larval emigration in the drainage basin. In combination with data collected from the spawning movements and destinations of radio-tagged and PIT-tagged adult suckers, this larval drift data will provide a baseline standard by which to determine the effects of dam removal on the spawning distribution of endangered Klamath Basin suckers in the Sprague River.

Ellsworth, Craig M.; Tyler, Torrey J.; VanderKooi, Scott P.; Markle, Douglas F.

2009-01-01

468

Singularities and Closed String Tachyons  

SciTech Connect

A basic problem in gravitational physics is the resolution of spacetime singularities where general relativity breaks down. The simplest such singularities are conical singularities arising from orbifold identifications of flat space, and the most challenging are spacelike singularities inside black holes (and in cosmology). Topology changing processes also require evolution through classically singular spacetimes. I briefly review how a phase of closed string tachyon condensate replaces, and helps to resolve, basic singularities of each of these types. Finally I discuss some interesting features of singularities arising in the small volume limit of compact negatively curved spaces and the emerging zoology of spacelike singularities.

Silverstein, Eva; /SLAC /Stanford U., Phys. Dept.

2006-03-17

469

Heavy ions and string theory  

E-print Network

We review a selection of recent developments in the application of ideas of string theory to heavy ion physics. Our topics divide naturally into equilibrium and non-equilibrium phenomena. On the non-equilibrium side, we discuss generalizations of Bjorken flow, numerical simulations of black hole formation in asymptotically anti-de Sitter geometries, equilibration in the dual field theory, and hard probes. On the equilibrium side, we summarize improved holographic QCD, extraction of transport coefficients, inclusion of chemical potentials, and approaches to the phase diagram. We close with some possible directions for future research.

Oliver DeWolfe; Steven S. Gubser; Christopher Rosen; Derek Teaney

2013-04-29

470

Topological amplitudes in string theory  

Microsoft Academic Search

We show that certain type II string amplitudes at genus $g$ are given by the\\u000atopological partition function $F_g$ discussed recently by Bershadsky, Cecotti,\\u000aOoguri and Vafa. These amplitudes give rise to a term in the four-dimensional\\u000aeffective action of the form $\\\\sum_g F_g W^{2g}$, where $W$ is the chiral\\u000asuperfield of $N=2$ supergravitational multiplet. The holomorphic anomaly of\\u000a$F_g$

I. Antoniadis; E. Gavab; K. S. Narainc; T. R. Taylor

1994-01-01

471

Melt dumping in string stabilized ribbon growth  

DOEpatents

A method and apparatus for stabilizing the edge positions of a ribbon drawn from a melt includes the use of wettable strings drawn in parallel up through the melt surface, the ribbon being grown between the strings. A furnace and various features of the crucible used therein permit continuous automatic growth of flat ribbons without close temperature control or the need for visual inspection.

Sachs, Emanuel M. (42 Old Middlesex Rd., Belmont, MA 02178)

1986-12-09

472

Anatomy of String Breaking in QCD  

E-print Network

We investigate the string breaking mechanism in n_f=2 QCD. We discuss the lattice techniques used and present results on energy levels and mixing angle of the static BBbar|QbarQ two-state system. The string breaking is visualized, by means of an animation of the action density distribution as a function of the static colour source-antisource separation.

Zdravko Prkacin; Gunnar S Bali; Thomas Dussel; Thomas Lippert; Hartmut Neff; Klaus Schilling

2005-10-07

473

Cosmic Rays from Cosmic Strings with Condensates  

E-print Network

We re-visit the production of cosmic rays by cusps on cosmic strings. If a scalar field (``Higgs'') has a linear interaction with the string world-sheet, such as would occur if there is a bosonic condensate on the string, cusps on string loops emit narrow beams of very high energy Higgses which then decay to give a flux of ultra high energy cosmic rays. The ultra-high energy flux and the gamma to proton ratio agree with observations if the string scale is $\\sim 10^{13}$ GeV. The diffuse gamma ray and proton fluxes are well below current bounds. Strings that are {\\it lighter} and have linear interactions with scalars produce an excess of direct and diffuse cosmic rays and are ruled out by observations, while heavier strings ($\\sim 10^{15}$ GeV) are constrained by their gravitational signatures. This leaves a narrow window of parameter space for the existence of cosmic strings with bosonic condensates.

Tanmay Vachaspati

2009-11-13

474

Magnetic Moment of Electrons near Cosmic Strings  

E-print Network

We study the effect of background geometry generated by a thin cosmic string on the anomalous magnetic moment of the electron. We find that the magnitude of the quantum correction to the magnetic moment depends on the distance from the cosmic string as well as on the deficit angle.

Takuya Maki; Kiyoshi Shiraishi

2014-01-27

475

A mini-course on topological strings  

Microsoft Academic Search

These are the lecture notes for a short course in topological string theory that I gave at Uppsala University in the fall of 2004. The notes are aimed at PhD students who have studied quantum field theory and general relativity, and who have some general knowledge of ordinary string theory. The main purpose of the course is to cover the

Marcel Vonk

2005-01-01

476

Topics in string theory and quantum gravity  

Microsoft Academic Search

These are the lecture notes for the Les Houches Summer School on Quantum Gravity held in July 1992. The notes present some general critical assessment of other (non-string) approaches to quantum gravity, and a selected set of topics concerning what we have learned so far about the subject from string theory. Since these lectures are long (133 A4 pages), we

Luís Alvarez-Gaumé; Miguel Angel Vázquez-Mozo

1992-01-01

477

Topics in String Theory and Quantum Gravity  

Microsoft Academic Search

These are the lecture notes for the Les Houches Summer School on Quantum Gravity held in July 1992. The notes present some general critical assessment of other (non-string) approaches to quantum gravity, and a selected set of topics concerning what we have learned so far about the subject from string theory. Since these lectures are long (133 A4 pages), we

L. Alvarez-Gaume; M. A. Vazquez-Mozo

1992-01-01

478

Strings in strongly correlated electron systems  

Microsoft Academic Search

It is shown that strongly correlated electrons on frustrated lattices like pyrochlore, checkerboard or kagome lattice can lead to the appearance of closed and open strings. They are resulting from nonlocal subsidiary conditions which propagating strongly correlated electrons require. The dynamics of the strings is discussed and a number of their properties are pointed out. Some of them are reminiscent

Peter Fulde; Frank Pollmann

2008-01-01

479

Sewing string tree vertices with ghosts  

E-print Network

It is shown how to sew string vertices with ghosts at tree level in order to produce new tree vertices using the Group Theoretic approach to String Theory. It is then verified the BRST invariance of the sewn vertex and shown that it has the correct ghost number.

L. Sandoval Jr

1999-09-22

480

Big bang models in string theory  

Microsoft Academic Search

These proceedings are based on lectures delivered at the 'RTN Winter School on Strings, Supergravity and Gauge Theories', CERN, 16 20 January 2006. The school was mainly aimed at PhD students and young postdocs. The lectures start with a brief introduction to spacetime singularities and the string theory resolution of certain static singularities. Then they discuss attempts to resolve cosmological

Ben Craps; Theoretische Natuurkunde

2006-01-01

481

Data-Parallel String-Manipulating Programs  

Microsoft Academic Search

Applications ranging from malware detection to graphics to Web security sanitization depend on string transformations, but writing such transformations is a challenge. Making these transformations run in parallel on a cluster of machines or special hardware is an even greater challenge. We answer this challenge with fast, parallel string manipulating code compiled from BEK, a domain-specific language for writing complex

Margus Veanes; David Molnar; Todd Mytkowicz; Benjamin Livshits

2012-01-01

482

Plucked String on a Shoestring Budget  

ERIC Educational Resources Information Center

The physics of the plucked string has been treated in many articles and books. For our 12th-grade high school physics laboratory, we have built a cheap, simple sonometer apparatus for each pair of students on which they may investigate some interesting phenomena that arise when a string is plucked. Among these are the generation of harmonics…

Gluck, Paul

2009-01-01

483

From Surface Roughening to QCD String Theory  

Microsoft Academic Search

Surface critical phenomena and the related onset of Goldstone modes represent fundamental properties of the confining flux in Quantum Chromodynamics. New ideas on surface roughening and their implications for lattice studies of quark confinement and string formation are presented. Problems with a simple string description of the large Wilson surface are discussed.

Keisuke Jimmy Juge; Julius Kuti; Colin Morningstar

2001-01-01

484

From surface roughening to QCD string theory  

SciTech Connect

Surface critical phenomena and the related onset of Goldstone modes represent fundamental properties of the confining flux in Quantum Chromodynamics. New ideas on surface roughening and their implications for lattice studies of quark confinement and string formation are presented. Problems with a simple string description of the large Wilson surface are discussed.

Keisuke Jimmy Juge et al.

2001-05-23

485

From Quantum Mechanics to String Theory  

E-print Network

From Quantum Mechanics to String Theory Relativity (why it makes sense) Quantum mechanics Dimensions Strings and the Strong Force Thursday, May 7, 2009 #12;Particle Interaction Summary quantum mechanics and special relativity together imply the existence of anti-particles forces are mediated

486

Three-dimensional gravity and string ghosts  

SciTech Connect

It is known that much of the structure of string theory can be derived from three-dimensional topological field theory and gravity. We show here that, at least for simple topologies, the string diffeomorphism ghosts can also be explained in terms of three-dimensional physics.

Carlip, S. (Department of Phyiscs, University of California, Davis, California 95616 (United States)); Kogan, I.I. (Department of Physics, University of British Columbia, Vancouver, British Columbia, V6T 2A6 (Canada))

1991-12-23

487

Bound states of string theory and beyond  

NASA Astrophysics Data System (ADS)

All bound states of fundamental strings, D-branes and NS-branes of string theory, both type-IIA and type-IIB, which may be described by a null geodesic motion on the coset G/K(G) where G is a group of type An, Dn or En embedded within E11 are presented.

Cook, Paul P.

2012-03-01

488

Quantum space foam and string theory  

SciTech Connect

String theory is originally defined as a modification of the Feynman rules in perturbation theory. It contains gravity in its perturbative spectrum. We review some recent developments which demonstrate that nonperturbative effects of quantum gravity, such as spacetime foam, arise in string theory as well.Prepared for the proceedings of 'Albert Einstein Century Conference' , Paris July 2005.

Nekrasov, Nikita [IHES, 35, Route de Chartres, Bures-sur-Yvette, F-91440 (France)

2006-11-03

489

New string theories and their generation number  

NASA Astrophysics Data System (ADS)

New heterotic string theories in four dimensions are constructed by tensoring a nonstandard SCFT along with some minimal SCFTs. All such theories are identified and their particle generation number is found. We prove that from the infinite number of new heterotic string theories only the {6} theory predicts three generations as seen in nature which makes it an interesting candidate for further study.

Genish, Arel; Gepner, Doron

2014-08-01

490

String Theory: Big Problem for Small Size  

ERIC Educational Resources Information Center

String theory is the most promising candidate theory for a unified description of all the fundamental forces that exist in nature. It provides a mathematical framework that combines quantum theory with Einstein's general theory of relativity. The typical size of a string is of the order of 10[superscript -33] cm, called the Planck length. But due…

Sahoo, S.

2009-01-01

491

5D black holes and matrix strings  

Microsoft Academic Search

We derive the world-volume theory, the (non)-extremal entropy and background geometry of black holes and black strings constructed out of the NS IIA 5-brane within the framework of matrix theory. The CFT description of strings propagating in the black hole geometry arises as an effective field theory.

Robbert Dijkgraaf; Erik Verlinde; Herman L Verlinde

1997-01-01

492

Stability of AdS black strings  

E-print Network

We review the recent developements in the stability problem and phase diagram for asymptotically locally $AdS$ black strings. First, we quickly review the case of locally flat black string before turning to the case of locally $AdS$ spacetimes.

T. Delsate

2008-08-14

493

Density fluctuations from strings and galaxy formation  

NASA Technical Reports Server (NTRS)

The spectra of density fluctuations caused by strings in a universe dominated either by baryons, neutrinos, or axions are presented. Realistic scenarios for galaxy formation seem possible in all three cases. Examples of grand unified theories which lead to strings with the desired mass scales are given.

Vilenkin, A.; Shafi, Q.

1983-01-01

494

A Computer String-Grammar of English.  

ERIC Educational Resources Information Center

This volume is the fourth in a series of detailed reports on a working computer program for the syntactic analysis of English sentences into their component strings. The report (1) records the considerations involved in various decisions among alternative grammatical formulations and presents the word-subclasses, the linguistic strings, etc., for…

Sager, Naomi

495

A comparative study of stringed instruments.  

PubMed

Many studies for stringed instruments exist. Most analyses have been made on violins, guitars, and pianos, but comparative studies on these and less popular instruments have not been done. Our research consists of an in depth analysis of a variety of stringed instruments. The experiments included spectrum analysis, body resonances using Chladni patterns, and high-speed videos to visually observe the string oscillation modes. A combination of these methods was performed on 13 different stringed instruments. The spectral analysis was done on all instruments with the strings plucked or picked at different locations. Corresponding high-speed video was taken on many to observe how the waves propagate along the string. The violin and viola were recorded when bowed to compare the images of the stings when plucked. String resonances were compared to the body resonances to see the synthesis between the two. Comparisons of the spectrum, body resonances, and string oscillations have been made between these instruments to gain a better understanding of how they operate and why each emits the unique sounds that it does. [This paper is complementary to the poster of Katarzyna Pomian at this conference.]. PMID:25235168

Ramsey, Gordon

2014-04-01

496

Phenomenology from the Landscape of String Vacua  

E-print Network

This article is the author's PhD thesis. After a review of string vacua obtained through compactification (with and wothout fluxes), it presents and describes various aspects of the Landscape of string vacua. At first it gives an introduction and an overview of the statistical study of the set of four dimensional string vacua, giving the detailed study of one corner of this set (G2-holonomy compactifications of M-theory). Then it presents the ten dimensional approach to string vacua, concentrating on the ten dimensional description of the Type IIA flux vacua. Finally it gives two examples of models having some interesting and characteristic phenomenological features, and that belong to two different corners of the Landscape: warped compactifications of Type IIB String Theory and M-theory compactifications on G2-holonomy manifolds.

Roberto Valandro

2008-01-03

497

String Gas Cosmology and Non-Gaussianities  

E-print Network

Recently it has been shown that string gas cosmology, an alternative model of the very early universe which does not involve a period of cosmological inflation, can give rise to an almost scale invariant spectrum of metric perturbations. Here we calculate the non-Gaussianities of the spectrum of cosmological fluctuations in string gas cosmology, and find that these non-Gaussianities depend linearly on the wave number and that their amplitude depends sensitively on the string scale. If the string scale is at the TeV scale, string gas cosmology could lead to observable non-Gaussianities, if it is close to the Planck scale, then the non-Gaussianities on current cosmological scales are negligible.

Bin Chen; Yi Wang; Wei Xue; Robert Brandenberger

2007-12-14

498

Null cosmological singularities and free strings  

SciTech Connect

We continue exploring free strings in the background of null Kasner-like cosmological singularities, following K. Narayan, arXiv:0904.4532. We study the free string Schrodinger wave functional along the lines of K. Narayan, arXiv:0807.1517. We find the wave functional to be nonsingular in the vicinity of singularities whose Kasner exponents satisfy certain relations. We compare this with the description in other variables. We then study certain regulated versions of these singularities where the singular region is replaced by a substringy but nonsingular region and study the string spectra in these backgrounds. The string modes can again be solved for exactly, giving some insight into how string oscillator states get excited near the singularity.

Narayan, K. [Chennai Mathematical Institute, SIPCOT IT Park, Padur PO, Siruseri 603103 (India)

2010-03-15

499

Exposure to bleached kraft pulp mill effluent disrupts the pituitary-gonadal axis of white sucker at multiple sites  

SciTech Connect

Recent studies have demonstrated reproductive problems in white sucker (Catostomus commersoni) exposed to bleached kraft pulp mill effluent (BKME) at Jackfish Bay on Lake Superior. These fish exhibit delayed sexual maturity, reduced gonadal size, reduced secondary sexual characteristics, and circulating steroid levels depressed relative to those of reference populations. The present studies were designed to evaluate sites in the pituitary-gonadal axis of prespawning white sucker affected by BKME exposure. At the time of entry to the spawning stream, plasma levels of immunoreactive gonadotropin (GtH)-II (LH-type GtH) in male and female white sucker were 30- and 50-fold lower, respectively, than the levels in fish from a reference site. A single intraperitoneal injection of D-Arg6, Pro9N-Et sGnRH (sGnRH-A, 0.1 mg/kg) increased plasma GtH levels in male and female fish at both sites, although the magnitude of the response was greatly reduced in BKME-exposed fish. Fish at the BKME site did not ovulate in response to sGnRH-A, while 10 of 10 fish from the reference site ovulated within 6 hr. Plasma 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P) levels were depressed in BKME-exposed fish and unlike fish at the reference site, failed to increase in response to sGnRH-A. Testosterone levels in both sexes and 11-ketostestosterone levels in males were elevated in fish from the reference site but were not further increased by GnRH treatment. In contrast, BKME-exposed fish exhibit a transitory increase in testosterone levels in response to the GnRH analog. In vitro incubations of ovarian follicles obtained from fish at the BKME site revealed depressed basal secretion of testosterone and 17,20 beta-P and reduced responsiveness to the GtH analog human chorionic gonadotropin and to forskolin, a direct activator of adenylate cyclase.

Van Der Kraak, G.J.; Munkittrick, K.R.; McMaster, M.E.; Portt, C.B.; Chang, J.P. (Department of Zoology, University of Guelph, Ontario (Canada))

1992-08-01

500

Natural quintessence in string theory  

SciTech Connect

We introduce a natural model of quintessence in string theory where the light rolling scalar is radiatively stable and couples to Standard Model matter with weaker-than-Planckian strength. The model is embedded in an anisotropic type IIB compactification with two exponentially large extra dimensions and TeV-scale gravity. The bulk turns out to be nearly supersymmetric since the scale of the gravitino mass is of the order of the observed value of the cosmological constant. The quintessence field is a modulus parameterising the size of an internal four-cycle which naturally develops a potential of the order (gravitino mass){sup 4}, leading to a small dark energy scale without tunings. The mass of the quintessence field is also radiatively stable since it is protected by supersymmetry in the bulk. Moreover, this light scalar couples to ordinary matter via its mixing with the volume mode. Due to the fact that the quintessence field is a flat direction at leading order, this mixing is very small, resulting in a suppressed coupling to Standard Model particles which avoids stringent fifth-force constraints. On the other hand, if dark matter is realised in terms of Kaluza-Klein states, unsuppressed couplings between dark energy and dark matter can emerge, leading to a scenario of coupled quintessence within string theory. We study the dynamics of quintessence in our set-up, showing that its main features make it compatible with observations.

Cicoli, Michele [Abdus Salam ICTP, Strada Costiera 11, Trieste 34014 (Italy); Pedro, Francisco G. [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford, OX1 3NP (United Kingdom); Tasinato, Gianmassimo, E-mail: mcicoli@ictp.it, E-mail: f.pedro1@physics.ox.ac.uk, E-mail: gianmassimo.tasinato@port.ac.uk [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth, PO1 3FX (United Kingdom)

2012-07-01