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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

Rod coupling for oil well sucker rods and the like  

SciTech Connect

A coupling is described for joining solid reciprocating sucker rods to form a rod string in a well pump or the like comprising a unitary metal sleeve having an axial threaded bore and an irregular outer surface, and a homogeneous and non-fibrous coating on the sleeve over the outer surface providing an externally substantially cylindrical coupling, the coating comprising a flexible and abrasive resistant thermoplastic hydrourethane polymer formed on the irregular outer surface of the sleeve while in the molten state.

Bowers, R.

1986-07-29

3

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

4

An Improved Finite-Difference Calculation of Downhole Dynamometer Cards for Sucker-Rod Pumps  

Microsoft Academic Search

Sucker-rod pumping is the most widely used means of artificial lift. About 85% to 90% of all producing wells in the U.S. are rod-pumped. Thus, a reliable method of analyzing these pumping system is a necessity. For many years, the surface dynamometer has been used to analyze sucker-rod systems. Interpretation of actual pump conditions from surface dynamometer cards is often

T. A. Everitt; J. W. Jennings

1992-01-01

5

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

E-print Network

DEVELOPMENT OF A NEW MODEL FOR PREDICTING SUCKER-ROD PUMPING SYSTEM PERFORMANCE A Thesis by JULIAN PEREZ GARCIA, JR. Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1988 Major Subject: Petroleum Engineering DEVELOPMENT OF A NEW MODEL FOR PREDICTING SUCKER-ROD PUMPING SYSTEM PERFORMANCE A Thesis by JULIAN PEREZ GARCIA, JR. Approved as to style and content by: J. . Jen in s (Cha...

Garcia, Julian Perez

2012-06-07

6

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

7

A Dynamic Investigation of Sucker-Rod Pumping  

E-print Network

.5 5.0 2.5 0 10 Displacement Total Rod Length Specific Gravity of Pumped Fluid API Pump Unit Size (Standard Design) Stroke Length Strokes per Minute Plunger Diameter Tubing Diameter Rod Diameter 3000 feet 0.90 114 54 inches 18 SPM 2... from saddle bearing feet to center of polished rod III I**-1 Weight per foot of length of lb ./feet rods of cross-section Al M 2 WM2 A2 M 3 WM3 A3 M4 1VM4 A4 PD PDM Pump displacement feet PRL PRL Polished rod load lb. 41 Description Units...

Knapp, Roy M.

1969-01-01

8

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

SciTech Connect

Sucker-rod pumping is the most widely used means of artificial lift. About 85% to 90% of all producing wells in the U.S. are rod-pumped. Thus, a reliable method of analyzing these pumping system is a necessity. For many years, the surface dynamometer has been used to analyze sucker-rod systems. Interpretation of actual pump conditions from surface dynamometer cards is often difficult, if not impossible. Results obtained from surface cards are strictly qualitative and are dependent on the analyzer's expertise. The ideal analysis procedure would be to measure the actual pump conditions with a downhole dynamometer. However, this situation is not economically feasible. Therefore, an accurate method of calculating downhole pump cards form measured surface cards is needed. This paper presents a method for calculating these downhole cards that uses a finite-difference representation of the wave equation. First, a brief description of previous calculation techniques is given.

Everitt, T.A. (Chevron Oil Field Research Co. (US))

1992-02-01

9

Fluid inertia consideration in sucker rod pump diagnosis  

E-print Network

such as stroke length, stroke rate, or pump size will result in increased production. '~ Diagnostic models use surface dynamometer cards to calculate pump cards. Surface dynamometer cards are plots of load versus position at the polished rod through time for a... of its stroke. From this position, the horse-head accelerates upwards liffing the rod sting and fluid towards the surface. At the end of the upstroke, the horse-head reaches its maximum distance from the ground. This point is located at the far right...

Csaszar, Albert Bela

2012-06-07

10

Relativistic elasticity of rigid rods and strings  

E-print Network

We show that the equation of motion for a rigid one-dimensional elastic body (i.e. a rod or string whose speed of sound is equal to the speed of light) in a two-dimensional spacetime is simply the wave equation. We then solve this equation in a few simple examples: a rigid rod colliding with an unmovable wall, a rigid rod being pushed by a constant force, a rigid string whose endpoints are simultaneously set in motion (seen as a special case of Bell's spaceships paradox), and a radial rigid string that has partially crossed the event horizon of a Schwarzschild black hole while still being held from the outside.

Jose Natario

2014-06-03

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

Shark Suckers: Remoras  

NSDL National Science Digital Library

Sharks and many other large ocean animals have sucker-equipped fish called remoras sticking to them. What are the remoras doing? Do they harm the sharks? In this video, Jonathan goes on a mission to investigate remoras and their role in the food web. He even sticks one on himself. Please see the accompanying study guide for educational objectives and discussion points.

Productions, Jonathan B.

2011-03-10

13

Morphometric and Meristic Differences among Bluehead Suckers, Flannelmouth Suckers, White Suckers, and Their Hybrids: Tools for the Management of Native Species in the Upper Colorado River Basin  

Microsoft Academic Search

Hybridization with nonnative fishes is a major factor influencing the status of native catostomids in the Colorado River basin. In Wyoming, hybridization with nonnative white suckers Catostomus commersonii is a particular concern in the conservation of native bluehead suckers C. discobolus and flannelmouth suckers C. latipinnis. The purpose of this study was to describe the meristic and morphometric characteristics of

Michael C. Quist; Michael R. Bower; Wayne A. Hubert; Thomas L. Parchman; David B. McDonald

2009-01-01

14

SiteSucker 1.6.3  

NSDL National Science Digital Library

It may happen that some Internet aficionados may want to download entire websites for easy access sometime in the future, or if they have to go offline for a period of time. SiteSucker 1.6.3 may be able to help, as the application has the ability to copy any site's web pages, images, backgrounds, movies, and other files to a local hard drive. This version of SiteSucker is compatible with all systems running Mac OS X and higher.

15

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

16

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

17

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

PubMed

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

Tramacere, Francesca; Appel, Esther; Mazzolai, Barbara; Gorb, Stanislav N

2014-01-01

18

Sitosterol sucroside from the suckers of Mentha arvensis  

Microsoft Academic Search

Two constituents, isolated from the suckers of Mentha arvensis, were identified as 3-O-?-sitosteryl-glucopyranosyl- (1? ? 2)-fructofuranoside and sucrose. © 1997 Elsevier Science Ltd. All rights reserved

Riaz A. Khan; Anil K. Singh; Pawan K. Agrawal

1997-01-01

19

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

20

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

21

Age-0 Lost River sucker and shortnose sucker nearshore habitat use in Upper Klamath Lake, Oregon: A patch occupancy approach  

USGS Publications Warehouse

We examined habitat use by age-0 Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris over six substrate classes and in vegetated and nonvegetated areas of Upper Klamath Lake, Oregon. We used a patch occupancy approach to model the effect of physical habitat and water quality conditions on habitat use. Our models accounted for potential inconsistencies in detection probability among sites and sampling occasions as a result of differences in fishing gear types and techniques, habitat characteristics, and age-0 fish size and abundance. Detection probability was greatest during mid- to late summer, when water temperatures were highest and age-0 suckers were the largest. The proportion of sites used by age-0 suckers was inversely related to depth (range = 0.4-3.0 m), particularly during late summer. Age-0 suckers were more likely to use habitats containing small substrate (64 mm) and habitats with vegetation than those without vegetation. Relatively narrow ranges in dissolved oxygen, temperature, and pH prevented us from detecting effects of these water quality features on age-0 sucker nearshore habitat use.

Burdick, S.M.; Hendrixson, H.A.; VanderKooi, S.P.

2008-01-01

22

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

23

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

24

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

25

Beachfront nourishment decisions: the "sucker-free rider" problem  

NASA Astrophysics Data System (ADS)

Coastal communities and beachfront property owners often respond to erosion by adding sand to restore local beaches. However, beach nourishment alters shoreline dynamics, not only at the replenishment site but also in adjacent coastal regions, as natural coastal processes shift sand from one location to another. The result is that "sucker" communities pay to build up their beaches, but that replenishment also helps protect the coastlines of "free rider" communities. The sucker-free rider situation is an example of a classic problem studied in economics and game theory frameworks.

Balcerak, Ernie

2013-06-01

26

Cryopreservation of Sperm of the Endangered Razorback Sucker  

Microsoft Academic Search

The endangered razorback sucker Xyrauchen texanus is endemic to the Colorado River system in western North America and is threatened with extinction because of limited recruitment. To assist in management and recovery efforts, we developed methods for the cryopreservation of sperm, evaluated the influence of various factors on motility of thawed sperm, and examined the effect on fertilization of cooling

Terrence R. Tiersch; Chester R. Figiel Jr; William R. Wayman; J. Holt Williamson; Gary J. Carmichael; Owen T. Gorman

1998-01-01

27

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

28

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

PubMed

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 (k(D) approximately 3 nM) and low capacity (B(max) approximately 73-81 nM) were identified in both species. Subsequent studies determined if the properties of the SBP in white sucker exposed to bleached kraft mill effluent (BKME) at Terrace Bay, ON, and in longnose sucker exposed to BKME at Grande Prairie, AB. differed from appropriate reference fish. There were no effects of BKME exposure on the binding affinity (k(D)) of the SBP in either species, but there was a significant increase in the binding capacity (B(max)) of longnose sucker SBP exposed to BKME. The livers of nai;ve white sucker exposed to effluent at Terrace Bay or a bleached sulfite/groundwood mill in Edmundston, NB, rapidly accumulated compounds of differing hydrophobicity that bound to both the white sucker and goldfish (Carassius auratus) SBP. Conversely, there was reduced accumulation of SBP ligands in the bile of effluent-exposed fish. We have demonstrated that constituents present within pulp mill effluent bind to both the white sucker and goldfish SBP, and that native species residing downstream of pulp mill effluents may experience modifications in the properties of their SBP. PMID:12600684

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

2003-02-01

29

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

30

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

31

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

32

Does feeding behavior facilitate trophic niche partitioning in two sympatric sucker species from the American Southwest?  

PubMed

We examined two sympatric desert fishes, Sonora suckers (Catostomus insignis) and desert suckers (Pantosteus clarkii), and asked, does feeding behavior facilitate trophic niche partitioning? To answer this question, we conducted laboratory-based feeding trials to determine whether morphology alone facilitates the diet separation between the relatively unspecialized, omnivorous Sonora sucker and the more morphologically specialized, algivorous desert sucker or whether behavioral differences accompany morphological specialization. We predicted that (1) algivorous desert suckers would maximize contact between jaws and substrate and produce a large mouth-gape to facilitate scraping attached food-material; (2) omnivorous Sonora suckers would be more effective suction feeders when consuming unattached food items from the benthos; and (3) because they are anatomically specialized for scraping, desert suckers could not alter their feeding behavior when presented with different prey types, whereas relatively unspecialized Sonora suckers could vary behavior with prey type. We found that both species maximized jaw contact when feeding on benthic-attached food, although desert suckers produced a greater gape area. We also found that Sonora suckers were more effective suction feeders when feeding on benthic-unattached prey. Counter to our initial predictions, both species altered key aspects of feeding behavior in response to different prey types/locations. It appears that both sucker species can function as generalist feeders to exploit a variety of prey types within their natural habitat; indeed, this behavioral versatility may allow desert and Sonora suckers to respond to the cyclic environmental changes that are characteristic of the aquatic habitats of the American Southwest. PMID:24457922

O'Neill, Matthew W; Gibb, Alice C

2014-01-01

33

BIOLOGY OF THE LEECH ACTINOBDELLA INEQUIANNULATA MOORE, 1901 (ANNELIDA: HIRUDINEA: RHYNCHOBDELLIDA: GLOSSIPHONIIDAE), PARASITIC ON THE WHITE SUCKER, CATOSTOMUS COMMERSONI LACEPEDE, 1803 AND THE LONGNOSE SUCKER, CATOSTOMUS CATOSTOMUS FORSTER, 1773, IN ALGONQUIN PROVINCIAL PARK, ONTARIO, CANADA  

EPA Science Inventory

Actinobdella inequiannulata was found on the white sucker, Catostomus commersoni, and less frequently on the longnose sucker, Catostomus catostomus, in Algonquin Provincial Park, Ontario, Canada. Catostomus commersoni parasitized with Act. inequiannulata was collected from July ...

34

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

35

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

Federal Register 2010, 2011, 2012, 2013

...season, when they migrate to spawning areas. Individuals typically become reproductively mature at 4 to 7 years old, and can live for several decades. The rationales for listing Lost River sucker and shortnose sucker were similar, and many...

2013-04-16

36

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

37

INTEGR. COMP. BIOL., 42:11461153 (2002) The Structure and Adhesive Mechanism of Octopus Suckers1  

E-print Network

1146 INTEGR. COMP. BIOL., 42:1146­1153 (2002) The Structure and Adhesive Mechanism of Octopus College, Ithaca, New York 14850 SYNOPSIS. Octopus suckers consist of a tightly packed three. INTRODUCTION Octopuses use suckers for a remarkable variety of tasks including anchoring the body

Meyers, Ron

38

75 FR 5279 - Sucker Creek Channel and Floodplain Restoration Project (Phase II), Rogue River-Siskiyou National...  

Federal Register 2010, 2011, 2012, 2013

...within a portion of the Sucker Creek watershed, located on private lands and lands...water quality in the upper Sucker Creek Watershed. The specific restoration goals associated...Service-managed lands within the Sucker Creek Watershed or from commercial sources. A team...

2010-02-02

39

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

E-print Network

curvature between points A and B is due to gas expansion. This expansion contributes to stroke loss and a consequent production loss. To minimize loss of stroke due to gas expansion the pump needs to be spaced with a minimum safe clearance between... the standing valve and the plunger once the plunger reaches the bottom of the stroke. Rules 1 and 2 were based on the above information. The two rules are essentially the same but only differ in the source of the benchmark data. The first precondition...

Derek, Henryk Jozef

2012-06-07

40

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

E-print Network

of the stroke. The traveling valve is open, and the standing valve is closed causing the weight of the fluid to be supported by the tubing. In Figure 3b the plunger is moving up near the bottom of the stroke. At this point the traveling valve is closed... the standing valve to open and allow fluid into the pump. In Figure 3c the plunger is at the top of the stroke. The traveling valve is still closed, the standing valve is still open, and the pump is full of fluid. In Figure 3d the plunger is moving down...

Everitt, Thomas Aaron

2012-06-07

41

Rodding Surgery  

MedlinePLUS

... and After Their Child is in the Hospital.” Potential Complications Rodding is major surgery, and as with any major surgical procedure, there are potential complications. Complications from surgery include risks related to ...

42

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...

43

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

44

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

45

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

46

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

47

Coupled economic-coastline modeling with suckers and free riders  

NASA Astrophysics Data System (ADS)

erosion is a natural trend along most sandy coastlines. Humans often respond to shoreline erosion with beach nourishment to maintain coastal property values. Locally extending the shoreline through nourishment alters alongshore sediment transport and changes shoreline dynamics in adjacent coastal regions. If left unmanaged, sandy coastlines can have spatially complex or simple patterns of erosion due to the relationship of large-scale morphology and the local wave climate. Using a numerical model that simulates spatially decentralized and locally optimal nourishment decisions characteristic of much of U.S. East Coast beach management, we find that human erosion intervention does not simply reflect the alongshore erosion pattern. Spatial interactions generate feedbacks in economic and physical variables that lead to widespread emergence of "free riders" and "suckers" with subsequent inequality in the alongshore distribution of property value. Along cuspate coastlines, such as those found along the U.S. Southeast Coast, these long-term property value differences span an order of magnitude. Results imply that spatially decentralized management of nourishment can lead to property values that are divorced from spatial erosion signals; this management approach is unlikely to be optimal.

Williams, Zachary C.; McNamara, Dylan E.; Smith, Martin D.; Murray, A. Brad.; Gopalakrishnan, Sathya

2013-06-01

48

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

49

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

50

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)

2004-01-01

51

Sperm quality assessments for endangered razorback suckers Xyrauchen texanus.  

PubMed

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; P<0.0001). Count (FCM) was negatively correlated with post-thaw viability (r=-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; P<0.0001) and pre-freeze viabilities (r=-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. PMID:20956577

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

2011-01-01

52

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

53

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

54

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

55

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

56

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

57

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

58

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

59

Unveiling the morphology of the acetabulum in octopus suckers and its role in attachment.  

PubMed

In recent years, the attachment mechanism of the octopus sucker has attracted the interest of scientists from different research areas, including biology, engineering, medicine and robotics. From a technological perspective, the main goal is to identify the underlying mechanisms involved in sucker attachment for use in the development of new generations of artificial devices and materials. Recently, the understanding of the morphology of the sucker has been significantly improved; however, the mechanisms that allow attachment remain largely unknown. In this work, we present new anatomical findings: specifically, a protuberance in the acetabular roof in five different octopus species; previously, this protuberance was identified by the authors in Octopus vulgaris. Moreover, we discuss the role of the protuberance and other anatomical structures in attachment with minimal energy consumption. PMID:25657834

Tramacere, Francesca; Pugno, Nicola M; Kuba, Michael J; Mazzolai, Barbara

2015-02-01

60

Development of a quantitative assay to measure expression of transforming growth factor ß (TGF-ß) in Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris) and evaluation of potential pitfalls in use with field-collected samples  

USGS Publications Warehouse

The Nature Conservancy is in the process of restoring the Williamson River Delta in an attempt to recreate important juvenile habitat for the endangered shortnose sucker Chasmistes brevirostris and the endangered Lost River sucker Deltistes luxatus. Measurement of TGF-? mRNA expression level was one of the indicators chosen to evaluate juvenile sucker health during the restoration process. TGF-? mRNA expression level has been correlated with disease status in several laboratory studies and TGF-? mRNA expression level has been used as a species-specific indicator of immune status in field-based fish health assessments. We describe here the identification of TGF-? and a possible splice variant from shortnose sucker and from Lost River sucker. The performance of a quantitative RT-PCR assay to measure TGF-? mRNA expression level was evaluated in field-collected spleen and kidney tissue samples. The quality of extracted RNA was higher in tissues harvested in September compared to July and higher in tissues harvested at lower temperature compared to higher temperature. In addition, the expression level of both TGF-? and 18S as assessed by qRT-PCR was higher in samples with higher quality RNA. TGF-? mRNA expression was lower in kidney than in spleen in both Lost River sucker and shortnose sucker.

Robertson, Laura S.; Ottinger, Christopher A.; Burdick, Summer M.; VanderKooi, Scott P.

2012-01-01

61

Gender Representations in BET’s 106 & Park and Sucker Free on MTV: A Content Analysis  

Microsoft Academic Search

A content analysis was conducted on the shows 106 & Park and Sucker Free on MTV for the time period of July 1st to August 31st 2006. Of the 92 videos shown, 43 were selected via random sample to create two ‘composite weeks’ for the viewing period of these shows. Coders were graduate and doctoral students in Florida State University

Kiva LaTouché

2007-01-01

62

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

63

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

64

Electron microscopy of some primary receptors in the sucker of Octopus vulgaris  

Microsoft Academic Search

Summary Electron microscopic observations are reported concerning the structure of sensory cells found in great numbers in the sucker ofOctopus vulgaris. These primary receptors have a variable number of cilia, whose structure closely resembles those previously described in motile cilia of vertebrates as well as invertebrate animals. The possibility that the intraepithelial receptors may be chemo-sensitive rather than mechanoreceptors is

P. Graziadei

1964-01-01

65

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

66

Comparison of White Sucker Age Estimates from Scales, Pectoral Fin Rays, and Otoliths  

Microsoft Academic Search

The ages of 229 white suckers Catostomus commersonii from six drainages in the upper Missouri River basin were estimated from scales, pectoral fin ray sections, and lapilli otolith sections to evaluate the potential bias of age estimates between structures. Age estimates were compared by calculating the coefficient of variation, average percent error, percent agreement, and percent agreement within 1 year,

Ryan M. Sylvester; Charles R. Berry Jr

2006-01-01

67

South Carolina Pest Management Handbook for Field Crops -2014 TOBACCO SUCKER CONTROL  

E-print Network

tobacco. Good sucker control reduces hand labor, and results in efficient use of harvesting equipment, or Drexalin Plus when combined with the proper use of contacts and MH, offer good season-long control days or more between MH application and harvest. (Harvesting too soon after MH application is a major

Duchowski, Andrew T.

68

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

E-print Network

tobacco. Good sucker control reduces hand labor, and results in efficient use of harvesting equipment, or Drexalin Plus when combined with the proper use of contacts and MH, offer good season-long control days or more between MH application and harvest. (Harvesting too soon after MH application is a major

Stuart, Steven J.

69

Pathogenesis of skin and liver neoplasms in white suckers from industrially polluted areas in Lake Ontario.  

PubMed

Increased prevalences of epidermal and hepatobiliary neoplasms in white suckers (Catostomu commersoni) and brown bullheads (Ictalurus nebulosus) in the Western region of Lake Ontario have been associated with industrial pollution, but the identity and causative role of environmental carcinogens have not yet been established. Most epidermal tumors of lip and body skin are benign focal proliferations that occur in fish from the polluted Hamilton region, and also in fish from less polluted sites in the Great Lakes. These skin tumors in white suckers do not have consistent alterations in cellular glutathione S-transferases (GST), suggesting that growth of skin tumors is not promoted by chemicals normally detoxified by GST. However, elevated levels of glutathione peroxidase (GPO) and glutathione reductase (GR) in skin papillomas are indicative of promotional peroxidative tissue injury, either caused directly by xenobiotics or indirectly by chemical-induced inflammation. Liver tumors in white suckers from Lake Ontario include preneoplastic, benign, and malignant populations of hepatocellular and biliary cells, all of which are more prevalent in fish from polluted sites. These liver tumors are consistently associated with chronic cholangiohepatitis and segmental cholangiofibrosis, but these conditions also occur in white suckers in non-industrial locations. Thus, the natural occurrence of biliary disease, not attributable to industrial pollution, may have some influence on the development of liver tumors. Some preneoplastic lesions and the majority of neoplastic hepatocellular and biliary lesions in white suckers have low levels of total GST, indicating that these liver neoplasms are not promoted by xenobiotics normally detoxified by hepatic GSTs.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2360036

Hayes, M A; Smith, I R; Rushmore, T H; Crane, T L; Thorn, C; Kocal, T E; Ferguson, H W

1990-05-01

70

Preliminary Testing of the Role of Exercise and Predator Recognition for Bonytail and Razorback Sucker  

USGS Publications Warehouse

SUMMARY Hatchery-reared juvenile, 45-cm TL) flathead catfish. Predator-nai??ve juveniles (20- to 25-cm TL) exhibited no discernable preference when provided areas with and without (52 percent and 48 percent, n = 16 observations; 46 percent and 54 percent, n = 20 observations) large flathead catfish. However, once predation occurred, use of predator-free areas nearly doubled in two trials (36 percent and 64 percent, n = 50 observations; 33 percent and 67 percent, n = 12 observations). A more stringent test examining available area indicated predator-savvy razorback suckers used predator-free areas (88 percent, n = 21) illustrating predator avoidance was a learned behavior. Razorback suckers exercised (treatment) in water current (<0.3 m/s) for 10 weeks exhibited greater swimming stamina than unexercised, control fish. When exercised and unexercised razorback suckers were placed together with large predators in 2006, treatment fish had significantly fewer (n = 9, z = 1.69, p = 0.046) mortalities than control fish, suggesting increased stamina improved predator escape skills. Predator/prey tests comparing razorback suckers that had been previously exposed to a predation event with control fish, found treatment fish also had significantly fewer losses than predator-nai??ve fish (p = 0.017). Similar tests exposing predator-savvy and predator-nai??ve bonytail with largemouth bass showed a similar trend; predator-savvy bonytail suffered 38 percent fewer losses than control fish. However, there was not a statistically significant difference between the test groups (p = 0.143) due to small sample size. All exercise and predator exposure trials increased the survival rate of razorback sucker and bonytail compared to untreated counterparts.

Mueller, Gordon A.; Carpenter, Jeanette; Krapfel, Robert; Figiel, Chester

2007-01-01

71

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

72

Temporal and spatial distribution of endangered juvenile Lost River and shortnose suckers in relation to environmental variables in Upper Klamath Lake, Oregon: 2009 annual data summary  

USGS Publications Warehouse

Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris) were listed as endangered in 1988 for a variety of reasons including apparent recruitment failure. Upper Klamath Lake, Oregon, and its tributaries are considered the most critical remaining habitat for these two species. Age-0 suckers are often abundant in Upper Klamath Lake throughout the summer months, but catches decline dramatically between late August and early September each year. Similar declines of age-1 suckers between spring and late summer also occur annually. These rapid declines in catch rates and a lack of substantial recruitment into adult sucker populations in recent years suggests sucker populations experience high mortality between their first summer and first spawn. Summer age-0 sucker habitat use and distribution have been studied extensively, but many uncertainties remain about age-1 and older juvenile habitat use, distribution, and movement patterns within Upper Klamath Lake. This study was designed to examine seasonal changes in distribution of age-1 suckers in Upper Klamath Lake as they relate to depth and water quality. The results of our third annual spring and summer sampling effort are presented in this report. Catch data collected in 2009 indicate seasonal changes in age-1 and older juvenile sucker habitat use coincident with changes in water quality. Although age-1 sucker catch rates were again concentrated along the western shore in June and early July, as they were in 2007 and 2008, very few age-1 suckers were captured in Eagle Ridge Trench in 2009 - a deepwater area along the western shore extending from Howard Bay to Eagle Ridge Point. Instead, suckers in 2009 were concentrated in the relatively shallow bays along the western shore. Nevertheless, as dissolved-oxygen concentrations decreased in mid-July below sublethal thresholds around the Eagle Ridge Trench, age-1 suckers apparently moved away from the western shore, and subsequently were captured in main lake areas and the eastern shore. Age-1 suckers were noticeably absent from the tributaries of Upper Klamath Lake during periods of chronically low dissolved-oxygen concentrations in the lake, refuting a previously untested hypothesis that tributaries were important age-1 sucker refuge habitats. In addition, declines in overall catch rates for age-1 suckers in August and September, despite intensive sampling, indicates that the apparent declines in abundance may be due to increased mortality and not due to sampling the wrong environments or poor detection probability. The remote detection of an age-1 juvenile sucker tagged in Short Creek and subsequently recaptured in the Link River array, more than 30 kilometers away, indicates the capacity of juvenile suckers to migrate relatively long distances. This knowledge, coupled with other remotely detected suckers in the Williamson River, indicates that juvenile sucker movement in Upper Klamath Lake may be common. In order to better quantify movement and potentially survival, future research should focus on tagging more juvenile suckers and taking advantage of the significant passive integrated transponder tag infrastructure throughout Upper Klamath Lake and its tributaries. In this data summary, we also describe the distribution of age-0 suckers in Upper Klamath Lake and its tributaries. These data corroborate findings from 2007 and 2008, which describe age-0 sucker habitat as shallow relative to depths available in Upper Klamath Lake. Similar to age-1 suckers, age-0 sucker abundances also appeared to decline in late summer, despite continued sampling throughout Upper Klamath Lake and its tributaries. In addition to low dissolved-oxygen concentrations, increased opercle deformity and anchor worm (Lernaea spp.) infection rates, as well as increased abundances of fathead minnows and other piscivorous non-native fish, may provide potential insight into the causes of juvenile sucker rarity. Opercle deformity r

Bottcher, Jared L.; Burdick, Summer M.

2010-01-01

73

String Telephones  

NSDL National Science Digital Library

Students investigate how sound travels through string and air. First, they analyze the sound waves with a paper cup attached to a string. Then, they combine the string and cup with a partner to model a string telephone. Finally, they are given a design challenge to redesign the string telephone for distance. They think about their model as it compares a modern telephone and the impact the invention of the telephone has had on society.

Integrated Teaching And Learning Program

74

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

75

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

76

Control rod drive  

DOEpatents

A control rod drive uses gravitational forces to insert one or more control rods upwardly into a reactor core from beneath the reactor core under emergency conditions. The preferred control rod drive includes a vertically movable weight and a mechanism operatively associating the weight with the control rod so that downward movement of the weight is translated into upward movement of the control rod. The preferred control rod drive further includes an electric motor for driving the control rods under normal conditions, an electrically actuated clutch which automatically disengages the motor during a power failure and a decelerator for bringing the control rod to a controlled stop when it is inserted under emergency conditions into a reactor core.

Hawke, Basil C. (Solana Beach, CA)

1986-01-01

77

Lightning discharge protection rod  

NASA Technical Reports Server (NTRS)

A system for protecting an in-air vehicle from damage due to a lighning strike is disclosed. It is an extremely simple device consisting of a sacrificial graphite composite rod, approximately the diameter of a pencil with a length of about five inches. The sacrificial rod is constructed with the graphite fibers running axially within the rod in a manner that best provides a path of conduction axially from the trailing edge of an aircraft to the trailing end of the rod. The sacrificial rod is inserted into an attachment hole machined into trailing edges of aircraft flight surfaces, such as a vertical fin cap and attached with adhesive in a manner not prohibiting the conduction path between the rod and the aircraft. The trailing end of the rod may be tapered for aerodynamic and esthetic requirements. This rod is sacrificial but has the capability to sustain several lightning strikes and still provide protection.

Bryan, Charles F., Jr. (inventor)

1987-01-01

78

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

Microsoft Academic Search

Wild populations of white suckers (Catostomus commersoni) were exposed to a fluctuating ambient pH regime (pH 7 to 4 to 7 to 4) in natural soft water. Blood and muscle ionic composition together with the net flux rate of acid-base equivalents, other ion transfers as well as unidirectional Na+ and Cl- exchanges were measured simultaneously in intact fish. Exposure to

Helve Hõbe; Brian R. McMahon

1988-01-01

79

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

Microsoft Academic Search

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 o0.4 to 78mg\\/L, and concentrations in

Steven J. Hamilton; Kevin J. Buhl; Fern A. Bullard; Susan F. McDonald

80

RESPIRATORY, VENTILATORY, ACIDBASE AND IONOREGULATORY PHYSIOLOGY OF THE WHITE SUCKER CATOSTOMUS COMMERSONI: THE INFLUENCE OF  

Microsoft Academic Search

SUMMARY Blood gases, acid-base status, plasma ions, respiration, ventilation and cardiovascular function were measured in white suckers, using standard cannulation methods. Basic respiratory parameters under normoxia were compared to those in the active, pelagic rainbow trout and in other benthic teleosts. Sustained environmental hyperoxia (350-550 torr) increased arterial O2 (102-392 torr) and venous O2 (17-80 torr) tensions so that blood

P. R. H. WILKES; R. L. WALKER; D. G. McDONALDf; C. M. WOODf

81

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

82

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

83

Effective size, census size, and genetic monitoring of the endangered razorback sucker, Xyrauchen texanus  

Microsoft Academic Search

For the past several decades the Lake Mohave population of the federally endangered razorback sucker, Xyrauchen texanus, has had no natural recruitment because of intensive predation on larvae by non-native fishes. In response to impending extirpation,\\u000a a repatriation program was implemented where larval razorbacks are collected from the wild following natural spawning, reared\\u000a in protective custody, and then repatriated at

Thomas F. Turner; Thomas E. Dowling; Paul C. Marsh; Brian R. Kesner; Anne T. Kelsen

2007-01-01

84

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

85

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

86

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, O.C.

1988-04-21

87

Status of rod consolidation  

SciTech Connect

Two of the factors that need to be taken into account with rod consolidation are (1) the effects on rods from their removal from the fuel assembly and (2) the effects on rods as a result of the consolidation process. Potential components of both factors are described in the report. Discussed under (1) are scratches on the fuel rod surfaces, rod breakage, crud, extended burnup, and possible cladding embrittlement due to hydrogen injection at BWRs. Discussed under (2) are the increased water temperature (less than 10/sup 0/C) because of closer packing of the rods, formation of crevices between rods in the close-packed mode, contact with dissimilar metals, and the potential for rapid heating of fuel rods following the loss of water from a spent fuel storage pool. Another factor that plays an important role in rod consolidation is the cost of disposal of the nonfuel-bearing components of the fuel assembly. Also, the dose rate from the components - especially Inconel spacer grids - can affect the handling procedures. Several licensing issues that exist are described. A list of recommendations is provided. 98 refs., 5 figs., 5 tabs.

Bailey, W.J.

1985-04-01

88

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

89

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

90

Algal Toxins in Upper Klamath Lake, Oregon: Linking Water Quality to Juvenile Sucker Health  

USGS Publications Warehouse

As the lead science agency for the Department of Interior, the U.S. Geological Survey is actively involved in resource issues in the Klamath River basin. Activities include research projects on endangered Lost River and shortnose suckers, threatened coho salmon, groundwater resources, seasonal runoff forecasting, water quality in Upper Klamath Lake and the Klamath River, nutrient cycling in wetlands, and assessment of land idling programs to reduce water consumption. Many of these studies are collaborations with various partners including Department of Interior agencies, Indian Tribes, and State agencies.

VanderKooi, S.P.; Burdick, S.M.; Echols, K.R.; Ottinger, C.A.; Rosen, B.H.; Wood, T.M.

2010-01-01

91

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

PubMed

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 were also immunostained by sucker antiserum, showing the same distribution patterns. These results confirm the presence of CRF mRNA and CRF peptide in the white sucker hypothalamus and support the view that the magnocellular and parvocellular neurons of the PON may be involved in the control of adrenocorticotropic hormone secretion from the pituitary in the white sucker. PMID:1571966

Okawara, Y; Ko, D; Morley, S D; Richter, D; Lederis, K P

1992-03-01

92

Foucault Rod Model  

NSDL National Science Digital Library

The Foucault Rod model displays the vibration of a circumnavigating rod. One end of the rod is firmly secured to a support. The free end of the rod has a weight attached, like the bob of a pendulum. The support of the rod is circumnavigating a central axis. The plane of swing of the Foucault rod is affected by the rotation in the same way as the Foucault pendulum is. The simulation shows simultaneously the motion with respect to the inertial coordinate system, and the motion as seen from a co-rotating point of view. For the co-rotating view there is a close-up view and an overview. You can examine and modify this simulation if you have EJS installed by right-clicking within the plot and selecting âOpen EJS Modelâ from the pop-up menu item. The Foucault Rod model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_nl_teunissen_foucault_rod.jar file will run the program if Java is installed. Additional information about this model can be found by visiting the authorâs web site: http://www.cleonis.nl/index.htm.

Teunissen, Cleon

2009-11-03

93

Rod sequence advisor  

SciTech Connect

During startup and power shaping maneuvers of boiling water reactors (BWR's), control rods are sequentially withdrawn from the reactor core. The withdrawal sequences determine the overall reactor power and the local core power density and are based on the knowledge of station engineers. It is important that the control rods are withdrawn in such a manner that the local power level does not become excessive while the desired reactor power is generated. Rules that constrain the relative positions of control rod groups have been developed to do this. While these rules are relatively simple, applying them to all possible movements of the 17 control rod groups in a typical BWR is complex and time consuming. SMARTRODS, is a rule based pilot expert system, was developed in LISP for the determination of the rod sequences.

Wood, R.M. (Syracuse Univ., NY (United States)); Lu, Yi (Kaman Sciences Corp., Utica, NY (United States)); Furia, R.V.; Thompson, R.J. (GPU Nuclear Corp., Parsippany, NJ (United States)); Lin, Ching-lu (Electric Power Research Institute, Palo Alto, CA (United States))

1992-01-01

94

Rod Photoreceptors Detect Rapid Flicker  

ERIC Educational Resources Information Center

Rod-isolation techniques show that light-adapted human rods detect flicker frequencies as high as 28 hertz, and that the function relating rod critical flicker frequency to stimulus intensity contains two distinct branches. (MLH)

Conner, J. D.; MacLeod, Donald I. A.

1977-01-01

95

Endocrine changes during natural spawning in the white sucker, Catostomus commersoni. II. Steroid hormones.  

PubMed

Blood samples were taken from white suckers (Catostomus commersoni) during their annual spring spawning migration and analyzed by radioimmunoassay for gonadotropin (GtH), estradiol-17 beta (E2), testosterone (T), 11-ketotestosterone (11-KT), 17 alpha-hydroxyprogesterone (17-P), 17 alpha-hydroxy-20 beta-dihydroprogesterone (17, 20-P), androstenedione (A), and cortisol. GtH, 17-P, and 17,20-P levels were low in prespawning fish of both sexes, rose to their highest levels in ovulated females and spawning males, and then fell to low levels in spent fish. In females, E2, T, and A levels were high in prespawning fish and declined significantly at ovulation, dropping to lowest levels in spent fish. In males, 11-KT, T, and A levels were highest in prespawning fish, and lowest in spent fish. Cortisol levels were highest in spermiating males and ovulated females. Plasma profiles of the sex steroids in the white sucker are very similar to those observed in the rainbow trout (Salmo gairdneri). PMID:6510694

Scott, A P; MacKenzie, D S; Stacey, N E

1984-12-01

96

Dispersal of larval suckers at the Williamson River Delta, Upper Klamath Lake, Oregon, 2006-09  

USGS Publications Warehouse

An advection/diffusion modeling approach was used to simulate the transport of larval suckers from spawning areas in the Williamson River, through the newly restored Williamson River Delta, to Upper Klamath Lake. The density simulations spanned the years of phased restoration, from 2006/2007 prior to any levee breaching, to 2008 when the northern part of the delta was reconnected to the lake, and 2009 when levees on both sides of the delta had been breached. Model simulation results from all four years were compared to field data using rank correlation. Spearman ? correlation coefficients were usually significant and in the range 0.30 to 0.60, providing moderately strong validation of the model. The correlation coefficients varied with fish size class in a way that suggested that the model best described the distribution of smaller fish near the Williamson River channel, and larger fish away from the channel. When Lost River and shortnose/Klamath largescale suckers were simulated independently, the correlation results suggested that the model better described the transport and dispersal of the latter species. The incorporation of night-time-only drift behavior in the Williamson River channel neither improved nor degraded correlations with field data. The model showed that advection by currents is an important factor in larval dispersal.

Wood, Tamara M.; Hendrixson, Heather A.; Markle, Douglas F.; Erdman, Charles S.; Burdick, Summer M.; Ellsworth, Craig M.; Buccola, Norman L.

2012-01-01

97

Temporal and Spatial Distribution of Endangered Juvenile Lost River and Shortnose Suckers in Relation to Environmental Variables in Upper Klamath Lake, Oregon: 2008 Annual Data Summary  

USGS Publications Warehouse

Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris) were listed as endangered in 1988 for a variety of reasons including apparent recruitment failure. Upper Klamath Lake, Oregon, and its tributaries are considered the most critical remaining habitat for these two species. Age-0 suckers are often abundant in Upper Klamath Lake throughout the summer months, but catches decline dramatically between late August and early September each year and age-1 and older sub-adult suckers are rare. These rapid declines in catch rates and a lack of substantial recruitment into adult sucker populations in recent years suggests sucker populations experience high mortality between their first summer and first spawn. A lack of access to, or abundance of, optimal rearing habitat may exacerbate juvenile sucker mortality or restrict juvenile growth or development. Summer age-0 sucker habitat use and distribution has been studied extensively, but many uncertainties remain about age-1 and older juvenile habitat use, distribution, and movement patterns within Upper Klamath Lake. We designed a study to examine seasonal changes in distribution of age-1 suckers in Upper Klamath Lake as they relate to depth and water quality. In this document, which meets our annual data summary and reporting obligations, we discuss the results of our second annual spring and summer sampling effort. Catch data collected in 2007 and 2008 indicate seasonal changes in age-1 and older juvenile sucker habitat use coincident with changes in water quality, which were previously undocumented. In both years during April and May, age-1 and older juvenile suckers were found in shallow water environments. Then, as water temperatures began to warm throughout Upper Klamath Lake in June, age-1 and older juvenile suckers primarily were captured along the western shore in some of the deepest available environments. Following a dramatic decrease in dissolved oxygen concentrations in Eagle Ridge Trench, juvenile suckers were no longer found along the western shore but were captured throughout the rest of Upper Klamath Lake. When dissolved oxygen concentrations were 4 milligrams per liter or greater along the western shore, juvenile sucker captures were again concentrated in that area. Although this pattern indicates that low dissolved oxygen concentration or another related water-quality limitation may force juvenile suckers to leave the western shore, it is unclear as to why age-1 and older juveniles might be attracted to the area in the first place. Understanding this apparent behavior could be important to managing habitat for these species. In this data summary, we also describe the distribution of catches of age-0 suckers and other fishes in Upper Klamath Lake. These data corroborate previous studies that describe age-0 sucker habitat as shallow relative to depths available in Upper Klamath Lake. In this study, we did not seek, nor find additional clarification on age-0 sucker habitat use and distribution in Upper Klamath Lake. Our brief description of the distribution and abundance of all other fish species caught provides a context in which to assess the rarity of juvenile suckers within the fish community of Upper Klamath Lake.

Burdick, Summer M.; VanderKooi, Scott P.

2010-01-01

98

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

99

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

100

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

101

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

102

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

103

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

104

Genetic diversity analysis of mitochondrial DNA control region in artificially propagated Chinese sucker Myxocyprinus asiaticus.  

PubMed

Abstract The genetic diversity of the three major artificially propagated populations of Chinese sucker, an endangered freshwater fish species, was investigated using the sequences of mitochondrial DNA (mtDNA) control regions. Among the 89 individuals tested, 66 variable sites (7.26%) and 10 haplotypes were detected (Haplotype diversity Hd?=?0.805, Nucleotide diversity ??=?0.0287). In general, genetic diversity was lower in artificially propagated populations than in wild populations. This reduction in genetic diversity may be due to population bottlenecks, genetic drift and human selection. A stepping-stone pattern of gene flow was detected in the populations studied, showing much higher gene flow between neighbouring populations. To increase the genetic diversity, wild lineages should be introduced, and more lineages should be shared among artificially propagated populations. PMID:24409897

Wan, Yuan; Zhou, Chun-Hua; Ouyang, Shan; Huang, Xiao-Chen; Zhan, Yang; Zhou, Ping; Rong, Jun; Wu, Xiao-Ping

2014-01-10

105

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

106

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

107

Cosmic strings  

SciTech Connect

Cosmic strings are linear topological defects that 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 that are based on fundamental physics. In contrast to inflation, they can also be observed directly through gravitational lensing and their characteristic microwave background anistropy. It has recently been discovered by F. Bouchet and myself that details of cosmic string evolution are very different from the so-called ''standard model'' that has been 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. 29 refs., 9 figs.

Bennett, D.P.

1988-07-01

108

Gonadotropin-releasing hormones in the brain and pituitary of the teleost, the white sucker.  

PubMed

The present study investigated GnRH forms within the brain of a representative of the order Cypriniformes, the white sucker, Catostomus commersoni, using HPLC, RIA, and immunocytochemistry. Several immunoreactive (ir) GnRH forms were identified in the brain of the white sucker by chromatography and radioimmunoassay, including ir-salmon GnRH, ir-lamprey GnRH-I and -III, and ir-chicken GnRH-II. Results from immunocytochemical studies were consistent with multiple GnRH forms distributed in different patterns, particularly for fibers. Neuronal perikarya containing ir-salmon GnRH and ir-lamprey-like GnRH were found laterally within the preoptic area and rostral hypothalamus. Cells containing exclusively ir-salmon GnRH appeared slightly more rostrally, but in the same region. Fibers containing ir-salmon GnRH and ir-lamprey-like GnRH were seen throughout the caudal telencephalon and extended into the diencephalon, toward the pituitary. Fibers containing ir-chicken-II-like GnRH were also seen in the caudal telencephalon, but were concentrated more dorsally in the diencephalon. Within the pituitary, fibers containing ir-salmon GnRH and ir-lamprey-like GnRH entered the neurohypophysis, but differed in their destinations. Fibers containing ir-salmon GnRH remained within the neurohypophysis, while fibers containing ir-lamprey-like GnRH targeted adenohypophyseal tissue. These findings are consistent with the hypothesis that multiple GnRH forms with multiple functions exist within the brain and pituitary of teleosts and provide further evidence of a lamprey-like GnRH within an early evolved teleost species. PMID:10764549

Robinson, T C; Tobet, S A; Chase, C; Waldron, T; Sower, S A

2000-03-01

109

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

110

String Shapes  

NSDL National Science Digital Library

In this activity, learners work together to make polygons (many-sided shapes) with string. Learners sit on the floor and hold onto a piece of string slid between their thumbs and index fingers. Learners explore how many different kinds of triangles and other shapes they can make by changing their hand positions. Use this activity to help learners explore polygons including convex and concave polygons and vertices.

Exploratorium

2010-01-01

111

Transducin translocation contributes to rod survival and enhances synaptic transmission from rods to rod bipolar cells  

PubMed Central

In rod photoreceptors, several phototransduction components display light-dependent translocation between cellular compartments. Notably, the G protein transducin translocates from rod outer segments to inner segments/spherules in bright light, but the functional consequences of translocation remain unclear. We generated transgenic mice where light-induced transducin translocation is impaired. These mice exhibited slow photoreceptor degeneration, which was prevented if they were dark-reared. Physiological recordings showed that control and transgenic rods and rod bipolar cells displayed similar sensitivity in darkness. After bright light exposure, control rods were more strongly desensitized than transgenic rods. However, in rod bipolar cells, this effect was reversed; transgenic rod bipolar cells were more strongly desensitized than control. This sensitivity reversal indicates that transducin translocation in rods enhances signaling to rod bipolar cells. The enhancement could not be explained by modulation of inner segment conductances or the voltage sensitivity of the synaptic Ca2+ current, suggesting interactions of transducin with the synaptic machinery. PMID:23836670

Majumder, Anurima; Pahlberg, Johan; Boyd, Kimberly K.; Kerov, Vasily; Kolandaivelu, Saravanan; Ramamurthy, Visvanathan; Sampath, Alapakkam P.; Artemyev, Nikolai O.

2013-01-01

112

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

113

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

114

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

115

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

116

Speeding Strings  

E-print Network

There is a class of single trace operators in ${\\cal N}=4$ Yang-Mills theory which are related by the AdS/CFT correspondence to classical string solutions. Interesting examples of such solutions corresponding to periodic trajectories of the Neumann system were studied recently. In our paper we study a generalization of these solutions. We consider strings moving with large velocities. We show that the worldsheet of the fast moving string can be considered as a perturbation of the degenerate worldsheet, with the small parameter being the relativistic factor $\\sqrt{1-v^2}$. The series expansion in this relativistic factor should correspond to the perturbative expansion in the dual Yang-Mills theory. The operators minimizing the anomalous dimension in the sector with given charges correspond to periodic trajectories in the mechanical system which is closely related to the product of two Neumann systems.

Andrei Mikhailov

2005-04-19

117

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 Peter

118

Loss of glutathione S-transferases in pollution-associated liver neoplasms in white suckers (Catostomus commersoni) from Lake Ontario.  

PubMed

White suckers (Catostomus commersoni) are one of two species of bottom-feeding fish in which various liver neoplasms are more prevalent in urban/industrial sites in western Lake Ontario than in less polluted sites in the Great Lakes. Previous studies indicate that white suckers excrete metabolites of various polycyclic aromatic hydrocarbons (PAHs) in bile, and that glutathione transferase (GST)-mediated conjugation is a major detoxification pathway for the PAH benzo[alpha]pyrene. To determine whether hepatocarcinogenesis in these wild fish is associated with induced GST-dependent resistance to carcinogens, we examined the expression of immunoreactive GSTs in liver neoplasms and putatively preneoplastic altered hepatocellular foci from white suckers collected from several polluted sites in western Lake Ontario. Histological sections of liver with altered hepatocellular foci, hepatocellular adenomas, hepatocellular carcinomas, bile duct adenomas and bile duct carcinomas were examined for GST immunoreactivity by the peroxidase-antiperoxidase (PAP) technique with polyclonal antiserum specific for all major GST isoenzyme subunits found in normal liver of white suckers. All bile duct adenomas, bile duct carcinomas and hepatocellular carcinomas were markedly or completely deficient in immunoreactive GST in comparison with surrounding normal hepatocytes. The majority of the hepatocellular adenomas were also deficient. Most altered hepatocellular foci had normal GST staining, but several GST-deficient altered hepatocellular foci were observed. However, none of the preneoplastic or advanced liver neoplasms expressed induced GST, suggesting that carcinogenesis is not associated with selection for GST-dependent resistance. Loss of hepatocellular GSTs may be incidental to neoplastic progression in these fish, or might be important in increasing susceptibility of some preneoplastic populations of hepatocytes to further DNA damage by environmental or endogenous chemicals that are normally detoxified by GSTs. PMID:1660792

Stalker, M J; Kirby, G M; Kocal, T E; Smith, I R; Hayes, M A

1991-12-01

119

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

120

The photic environment and scotopic visual pigments of the creek chub, Semotilus atromaculatus and white sucker, Catostomus commersoni  

Microsoft Academic Search

Scotopic visual pigments measured in the creek chub and the white sucker are porphyropsins with mean ?max values located at 538.3 and 536.5 nm, respectively. There is a shift of the ?max towards shorter wavelengths during the winter in both of these species coinciding with similar changes in the quality of downwelling light. ?max is significantly correlated to the ?P50

P. H. Heinermann; M. A. Ali

1989-01-01

121

Disappearing Glass Rods  

NSDL National Science Digital Library

In this optics activity, learners discover how they can make glass objects "disappear." Learners submerge glass objects like stirring rods into a beaker of Wesson™ oil to explore how the principles of reflection and refraction affect what we see. Use this activity as a demonstration or allow learners to experiment on their own.

2011-12-05

122

Effects of natural exposure to copper and zinc on egg size and larval copper tolerance in white sucker (Catostomus commersoni).  

PubMed

Sucker eggs were collected from a metal-contaminated site where previous collections had documented a maternal yolk factor associated with an increased larval copper tolerance during yolk nutrition. In this study, white sucker eggs were divided into groups which were water hardened and/or incubated at the contaminated site or a reference (control) site. Incubation at the contaminated site was associated with a decreased egg size and an increased deformity rate, but had no effect on fertilization rate or larval size. Incubation in contaminated streams increased the larval whole-body metal content, and decreased the tolerance and resistance of larvae exposed to copper in laboratory bioassays. An increase in water temperature accelerated the developmental rate of the larvae, but had no detectable effect on copper tolerance. Although metals did enter the eggs during water hardening, there was no difference in egg metallothionein content, and the lack of obvious hepatic activity until several days after hatching may prevent the formation of protective proteins. The authors hypothesize that the transfer of metals to white sucker eggs in association with yolk precursors, and the subsequent mobilization of these metals during yolk utilization, can account for the observed differences in larval tolerance and growth. PMID:2776686

Munkittrick, K R; Dixon, D G

1989-08-01

123

Milt characteristics, reproductive performance, and larval survival and development of white sucker exposed to bleached kraft mill effluent  

SciTech Connect

White sucker from a Lake Superior bay which receives bleached kraft mill effluent (BKME) show increased hepatic mixed-function oxygenase (MFO) activity, reduced plasma sex steroid levels, decreased egg and gonad size, a decrease in the occurrence of secondary sexual characteristics, and an increased age to maturation. This study evaluated the reproductive performance of that white sucker population relative to a similar reference population. Spawning male white sucker from the BKME site had reduced spermatozoan motility but no significant differences in milt volume, spermatocrit levels, or seminal plasma constituents. BKME male and female fish had equal or greater fertilization potential compared to both male and female fish at the reference site. There was no difference either in the hatchability of the eggs or in larval size at hatch. BKME larvae did show reduced growth rates by 24 days posthatch but showed equal rates of yolk utilization. No difference in larval MFO activity was detected between sites at 21 days posthatch, indicating no parental transfer of induction to the progeny.

McMaster, M.E.; Portt, C.B.; Munkittrick, K.R.; Dixon, D.G. (Department of Biology, University of Waterloo, Ontario, (Canada))

1992-02-01

124

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

125

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

126

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

127

Isolation of MFO inducers from tissues of white suckers caged in bleached kraft mill effluent.  

PubMed

White sucker (Catostomus commersoni) caged for 3 days in a bleached kraft mill effluent (BKME) stream had elevated mixed function oxygenase (MFO) activities 15-90 fold those of fish caged in a reference stream. Liver composites of male and female fish were ground and extracted with dichloromethane (DCM), methanol or 50% DCM/methanol, and tested for MFO activity in rat hepatoma cells (H4IIE). There was no difference in the potency of H4IIE EROD induction among the three solvents, so DCM extracts were split into 31 fractions using reverse phase high pressure liquid chromatography (HPLC). H4IIE MFO activity was elevated in several fractions, with three early peaks and several later peaks of induction, indicating several classes or compounds causing MFO induction were present in the fish livers. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and chlorinated diphenylethers (CDPEs) were detected in several late-eluting fractions, but concentrations were not high enough for these compounds to be solely responsible for the observed induction. Induction by liver extracts decreased as cell exposure times increased (24, 48 or 72 h), suggesting that some inducers were more easily metabolized and eliminated from the H4IIE cells. In contrast, 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD) had similar potency over 24, 48 and 72 h, as it was relatively resistant to metabolism. PMID:10879827

Parrott, J L; van den Heuvel, M R; Hewitt, L M; Baker, M A; Munkittrick, K R

2000-10-01

128

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

129

Learning string edit distance  

Microsoft Academic Search

In many applications, it is necessary to determine the similarity of two strings. A widely-used notion of string similarity is the edit distance: the minimum number of insertions, deletions, and substitutions required to transform one string into the other. In this report, we provide a stochastic model for string edit distance. Our stochastic model allows us to learn a string

Eric Sven Ristad; Peter N. Yianilos

1996-01-01

130

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

131

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

132

Oxidative stress and bioindicators of reproductive function in pulp and paper mill effluent exposed white sucker.  

PubMed

This study investigates oxidative stress and bioindicators of reproductive function in wild white sucker (Catostomus commersoni) 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 collected downstream of pulp and paper mills within the Moose River basin exhibited elevated hepatic and gonadal 2-thiobarbituric acid reactive substances (TBARS), the presence of which is indicative of oxidative stress in these tissues. Within the Jackfish Bay system, exposure to pulp and paper mill effluent did not elevate hepatic or gonadal TBARS. Hepatic cytochrome P4501A activity (CYP1A) and fatty acyl-CoA oxidase (FAO) activities were frequently increased in livers of Moose River basin fish exposed to pulp and paper mill effluent, while lower activities of both enzymes were found within fish from the Jackfish Bay system. This suggests that oxidative stress may be related to CYP1A and FAO activities. Within the Moose River system, increases in measures of oxidative stress (TBARS, FAO) were generally coincident with decreased levels of 17 beta-estradiol; however, testosterone was often lower in Jackfish Bay system fish without any commensurate changes in oxidative stress. The suite of reproductive and oxidative stress parameters measured in this study varied between seasons and mills suggesting responses to effluent are dynamic and effects are complicated by different receiving environments. The relationship between gonad size, gonadal oxidative stress, and circulating plasma steroids remains unclear. PMID:12730610

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

2003-07-01

133

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

134

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

135

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

136

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

137

Efficacy of hydrogen peroxide in controlling mortality associated with saprolegniasis on walleye, white sucker, and paddlefish eggs  

USGS Publications Warehouse

The efficacy of hydrogen peroxide in controlling saprolegniasis on eggs of walleye Stizostedion vitreum, white sucker Catostomus commersoni, and paddlefish Polyodon spathula was evaluated at four private, state, and federal production hatcheries participating in an Investigational New Animal Drug efficacy study (experiment 1; walleyes) and in a laboratory-based miniature egg jar incubation system (experiment 2; walleyes, white suckers, and paddlefish). Naturally occurring fungal infestations (saprolegniasis) were observed on eggs in both experiments. Confirmatory diagnosis of infested eggs from one hatchery in experiment 1 identified the pathogen as Saprolegnia parasitica. During experiment 1, eggs were treated daily for 15 min with either 0, 500, or 750 mg/L of hydrogen peroxide, and one trial compared a 500-mg/L hydrogen peroxide treatment with a formalin treatment at 1,667 mg/L. Saprolegniasis infestation was observed in control egg jars, whereas treatment with either formalin or hydrogen peroxide virtually eliminated the infestation. Hydrogen peroxide treatments of 500 mg/L either increased egg hatch or were as effective as physical removal of infested eggs in controlling mortality. Although treatment with formalin at 1,667 mg/L significantly increased the percent eye-up of walleye eggs compared with that of those treated with hydrogen peroxide at 500 mg/L, the difference was only 1.9-2.6%. In experiment 2, noneyed eggs were treated for 15 min every other day with 0, 283, 565, or 1,130 mg/L of hydrogen peroxide until the viable eggs hatched. Saprolegniasis infestation engulfed most control eggs, whereas infestation of treated eggs was either reduced or not visible. Hydrogen peroxide significantly increased egg hatch for all three species tested in experiment 2. Although hydrogen peroxide treatments as low as 283 mg/L significantly increased walleye and white sucker hatch, treatments between 500 and 1,000 mg/L are more likely to be effective in production egg incubation systems.

Gaikowski, M.P.; Rach, J.J.; Drobish, M.; Hamilton, J.; Harder, T.; Lee, L.A.; Moen, C.; Moore, A.

2003-01-01

138

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

PubMed Central

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 (LC50) and the median lethal time (LT50) were determined to evaluate acute lethal effects on Chinese suckers. The results showed that the LC50 values of 4, 6, 8, and 10 h were 142%, 137%, 135%, and 130%, respectively. The LT50 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 LT50. 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 3/5LT50 (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 3/5LT50 (P>0.05), but the activities were significantly lower than the normal level at 4/5LT50 and LT50 (P<0.05). PMID:23024046

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

2012-01-01

139

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

140

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

141

Distribution and condition of young-of-year Lost River and shortnose suckers in the Williamson River Delta restoration project and Upper Klamath Lake, Oregon, 2008-10--Final Report  

USGS Publications Warehouse

We were unable to compare health and condition of juvenile suckers among habitats, due to their movement among habitats. However, documentation of length-weight relationships, afflictions and deformities, and histology indicated juvenile suckers captured in all habitats maintained a similar level of health among the 3 years of our study.

Burdick, Summer M.; Hewitt, David A.

2012-01-01

142

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

PubMed

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% heatinactivated white sucker serum (WSS) at 10 degrees C and 18 degrees C. The numbers of C. catostomi counted were significantly higher in cultures incubated at 10 degrees C than in those incubated at 18 degrees C beginning at 3 weeks post-incubation. The culture forms (from the eighth subculture at 9 months after isolation) were morphologically similar to blood forms and were infective to laboratory-raised white suckers. The parasite survived for about 4 weeks in the medium without WSS at 18 degrees C. The present study indicates that WSS supplement supports the in vitro multiplication of C. catostomi and that its multiplication is temperature-dependent. PMID:8801566

Li, S; Woo, P T

1996-01-01

143

Regulation of melatonin secretion by light in the isolated pineal organ of the white sucker (Catostomus commersoni).  

PubMed

The effects of different lighting conditions and physical parameters of light were investigated in the isolated pineal organ of the white sucker kept under static or superfusion culture. The secretion of pineal melatonin is directly controlled by the photoperiod and completely suppressed under constant illumination. When pineal organs are exposed to unexpected light at night, the secretion of melatonin is significantly reduced within 15 min and reaches basal value after 30-35 min of light treatment. The inhibition of melatonin secretion by unexpected light at night depends on the irradiance, duration, timing of the treatment and the lighting history of the pineal organ. PMID:7496394

Bolliet, V; Falcón, J; Ali, M A

1995-07-01

144

Piston and connecting rod assembly  

NASA Technical Reports Server (NTRS)

A piston and connecting rod assembly includes a piston crown, a piston skirt, a connecting rod, and a bearing insert. The piston skirt is a component separate from the piston crown and is connected to the piston crown to provide a piston body. The bearing insert is a component separate from the piston crown and the piston skirt and is fixedly disposed within the piston body. A bearing surface of a connecting rod contacts the bearing insert to thereby movably associate the connecting rod and the piston body.

Brogdon, James William (Inventor); Gill, David Keith (Inventor); Chatten, John K. (Inventor)

2001-01-01

145

Modeling Fractions with Cuisenaire Rods  

NSDL National Science Digital Library

In this interactive simulation students must determine the values for each of the Cuisenaire Rods based on the information that they are given in the prompt. This activity allows students to reason about how fractional values change based on the size of the whole. Students may use the Cuisenaire Rod activity space or use hands-on manipulatives to complete this activity.

2013-01-01

146

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

147

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

148

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

149

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

150

String Gas Cosmology  

E-print Network

String gas cosmology is a string theory-based approach to early universe cosmology which is based on making use of robust features of string theory such as the existence of new states and new symmetries. A first goal of string gas cosmology is to understand how string theory can effect the earliest moments of cosmology before the effective field theory approach which underlies standard and inflationary cosmology becomes valid. String gas cosmology may also provide an alternative to the current standard paradigm of cosmology, the inflationary universe scenario. Here, the current status of string gas cosmology is reviewed.

Brandenberger, Robert H

2009-01-01

151

Fluid Mechanics of Strings  

E-print Network

We consider conserved currents in an interacting network of one-dimensional objects (or strings). Singular currents localized on a single string are considered in general, and a formal procedure for coarse-graining over many strings is developed. This procedure is applied to strings described by the Nambu-Goto action such as cosmic strings. In addition to conserved currents corresponding to the energy-momentum tensor, we consider an antisymmetric tensor of conserved currents related to the string tangent vector. Under the assumption of local equilibrium we derive a complete set of hydrodynamic equations for strings.

Daniel Schubring; Vitaly Vanchurin

2013-05-29

152

Terahertz pinch harmonics enabled by single nano rods.  

PubMed

A pinch harmonic (or guitar harmonic) is a musical note produced by lightly pressing the thumb of the picking hand upon the string immediately after it is picked [J. Chem. Educ. 84, 1287 (2007)]. This technique turns off the fundamental and all overtones except those with a node at that location. Here we present a terahertz analogue of pinch harmonics, whereby a metallic nano rod placed at a harmonic node on a terahertz nanoresonator suppresses the fundamental mode, making the higher harmonics dominant. Strikingly, a skin depth-wide nano rod placed at the mid-point turns off all resonances. Our work demonstrates that terahertz electromagnetic waves can be tailored by nanoparticles strategically positioned, paving important path towards terahertz switching and detection applications. PMID:22109504

Park, Hyeong-Ryeol; Bahk, Young-Mi; Choe, Jong Ho; Han, Sanghoon; Choi, Seong Soo; Ahn, Kwang Jun; Park, Namkyoo; Park, Q-Han; Kim, Dai-Sik

2011-11-21

153

D-strings and f-strings from string loops  

E-print Network

Since the background fields of the string low energy action are supposed to be the long range manifestation of a condensate of strings, the addition of world sheet actions to the low energy effective action needs some string theoretic explanation. In this paper we suggest that this may be understood, as being due to string loop effects. We first present arguments using an equation due to Tseytlin and then more rigorously in the particular case of Type IIB theory by invoking the Fischler-Susskind effect. The argument provides further justification for {\\rm SL}(2,Z) duality between D-strings and F(fundamental)-strings. In an appendix we comment on recent attempts to relate the type IIA membrane to the 11 dimensional membrane.

de Alwis, S P

1996-01-01

154

Learning String Edit Distance  

Microsoft Academic Search

In many applications, it is necessary to determine the similarity of two strings. A widely-used notion of string similarity is the edit distance: The minimum number of insertions, deletions, and substitutions required to transform one string into the other. In this report, we provide a stochastic model for string-edit distance. Our stochastic model allows us to learn a string-edit distance

Eric Sven Ristad; Peter N. Yianilos

1997-01-01

155

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

156

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...

157

Quantum cards and quantum rods  

E-print Network

Quantum mechanical analysis of a rigid rod with one end fixed to a flat table is presented. It is shown, that for a macroscopic rod the ground state is orientationally delocalized only if the table is absolutely horizontal. In this latter case the rod, assumed to be initally in the upright orientation, falls down symmetrically and simultaneously in both directions, as claimed by Tegmark and Wheeler. In addition, the time of fall is calculated using WKB wavefunctions representing energy eigenstates near the barrier summit.

Milan Batista; Joze Peternelj

2006-11-02

158

String Field Theory  

E-print Network

This elementary introduction to string field theory highlights the features and the limitations of this approach to quantum gravity as it is currently understood. String field theory is a formulation of string theory as a field theory in space-time with an infinite number of massive fields. Although existing constructions of string field theory require expanding around a fixed choice of space-time background, the theory is in principle background-independent, in the sense that different backgrounds can be realized as different field configurations in the theory. String field theory is the only string formalism developed so far which, in principle, has the potential to systematically address questions involving multiple asymptotically distinct string backgrounds. Thus, although it is not yet well defined as a quantum theory, string field theory may eventually be helpful for understanding questions related to cosmology in string theory.

Washington Taylor

2006-06-28

159

Exposure to bleached kraft pulp mill effluent disrupts the pituitary-gonadal axis of white sucker at multiple sites.  

PubMed

Our 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. By comparison, ovarian follicles from fish collected at BKME and reference sites produced similar levels of prostaglandin E basally and in response to a phorbol ester and calcium ionophore A23187, suggesting that BKME effects on ovarian function are selective and do not reflect a general impairment of ovarian function. BKME-exposed fish had plasma levels of testosterone glucuronide proportionately lower than those of reference fish, suggesting that there are site differences in the peripheral metabolism of steroids. These studies demonstrate that BKME exposure affects reproduction by acting at multiple sites in the pituitary-gonadal axis. PMID:1641856

Van der Kraak, G J; Munkittrick, K R; McMaster, M E; Portt, C B; Chang, J P

1992-08-01

160

Using spatial, seasonal, and diel drift patterns of larval Lost River suckers Deltistes luxatus (Cypriniformes: Catostomidae) and shortnose suckers Chasmistes brevirostris (Cypriniformes: Catostomidae) to help identify a site for a water withdrawal structure on the Williamson River, Oregon  

USGS Publications Warehouse

A small irrigation diversion dam near Chiloquin, Oregon, was removed and replaced with a pump station to improve fish passage for Lost River suckers (Deltistes luxatus) and shortnose suckers (Chasmistes brevirostris) entering the Sprague River on their spawning migrations. During the developmental phase of the pump station, a need was identified to better understand the larval drift characteristics of these endangered catostomids in order to reduce entrainment into the irrigation system. The spatial, seasonal, and diel distribution of drifting larvae was measured during the 2004 spawning season at two proposed sites on the Williamson River where the pump station could be located. Larval drift for both species coincided with the irrigation season making them subject to entrainment into the irrigation system. Drift occurred almost exclusively at night with larvae entering the drift at sunset and exiting the drift at sunrise. Nighttime larval densities were concentrated near the surface and at midchannel at both sites. Densities were generally greater on the side of mid-channel with greater flow. During early morning sampling we detected a general shift in larval drift from surface to subsurface drift. We also observed an increase in larval densities towards the shore opposite from the proposed pump station at the upper site whereas larval densities remained high at midchannel at the lower site. During daytime sampling, the few larvae that were collected were distributed throughout the water column at both pump sites. This study found that larvae drifting during all time periods were generally distributed further across the cross section, deeper in the water column, and closer to where the proposed water withdrawal structure would be built at the downstream site when compared to the upstream site. Recommendations were provided to locate the withdrawal facility at the upstream site and operate it in a manner such that larval entrainment would likely be minimized.

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

2010-01-01

161

Modeling Fractions with Cuisenaire Rods  

NSDL National Science Digital Library

In this interactive activity adapted for grades 3–5 from Annenberg Learner’s Teaching Math Grades 6–8, use virtual Cuisenaire® Rods to represent fractions and to perform operations with fractions.

Foundation, Wgbh E.

2012-06-29

162

FABRICATION OF FUEL RODS BY TANDEM ROLLING  

Microsoft Academic Search

The tandem rolling process used industrially to manufacture tubular ; resistance heating elements was investigated to determine its applicability for ; fabricating rod-type fuel elements. Approximately 90 stainless steel clad fuel ; rods containing natural UOâ were tandem-rolled to establish optimum rolling ; parameters and fuel rod design. Fuel rod diameter, cladding wall thickness, UO\\/; sub 2\\/ particle size, rolling

Lingafelter

1961-01-01

163

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

PubMed

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 the large cells in the spinal cord proper. The possibility that the caudal neurosecretory system is not a functionally uniform system but rather a collection of dissimilar cells of different synaptic inputs with a common entity, urotensin I, is discussed. Moreover, the feasibility of a urotensin-I feedback loop is described. PMID:6365325

Fisher, A W; Wong, K; Gill, V; Lederis, K

1984-01-01

164

Elevated ovarian follicular apoptosis and heat shock protein-70 expression in white sucker exposed to bleached kraft pulp mill effluent.  

PubMed

Exposure of feral fish populations to bleached kraft pulp mill effluent (BKME) results in a variety of negative impacts on reproductive fitness including reduced ovarian development, reduced egg size, decreased fecundity with age, delayed sexual maturation, and alterations in reproductive endocrine homeostasis at multiple sites along the pituitary-gonadal axis. The present study provides evidence of elevated apoptotic DNA fragmentation and increased expression of the 70-kDa heat shock protein (HSP70) in ovarian follicular cells from prespawning white sucker (Catostomus commersoni) exposed to BKME. Apoptosis is the molecular mechanism responsible for ovarian follicular atresia which is involved in various stages of vertebrate ovarian development such as follicular recruitment, growth, differentiation, and regression. In mammals, induction of HSP70 is associated with inhibition of hormone-sensitive steroidogenesis and mediation of luteal regression. The 3'-end labeling of isolated ovarian follicular cell DNA revealed a 10-fold increase in the extent of apoptosis in BKME-exposed white sucker in comparison to follicles collected from a nearby reference site. Western blotting for ovarian follicular HSP70 levels showed increased expression of this protein in fish exposed to BKME. The elevated ovarian cell apoptosis and increased HSP70 expression in BKME-exposed fish were associated with reduced ovary size, decreased plasma testosterone, and increased plasma 17 beta-estradiol concentrations, but not induction of hepatic ethoxyresorufin O-deethylase activity. It is not known whether increased ovarian HSP70 expression in BKME-exposed fish is related to elevated apoptosis or represents a general response to environmental stress. Since apoptosis is regulated by several hormonal factors and conserved gene products, these data suggest that certain components of BKME increase ovarian cell apoptosis in fish via stimulation of cell death signaling. However, it is unclear whether BKME stimulates ovarian cell apoptosis directly or if this response occurs secondarily as a result of altered reproductive endocrine homeostasis. PMID:9439734

Janz, D M; McMaster, M E; Munkittrick, K R; Van der Kraak, G

1997-12-01

165

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

166

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

167

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

168

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

169

Twisted strings and orbifolds  

SciTech Connect

Orbifold compactifications provide a practical approach to string symmetry breaking. They have the potential to bridge the gap between string theory and the physics of the standard model. 7 refs., 5 figs.

Bagger, J.A.

1986-08-01

170

String resistance detector  

NASA Technical Reports Server (NTRS)

Method and system are disclosed for determining individual string resistance in a network of strings when the current through a parallel connected string is unknown and when the voltage across a series connected string is unknown. The method/system of the invention involves connecting one or more frequency-varying impedance components with known electrical characteristics to each string and applying a frequency-varying input signal to the network of strings. The frequency-varying impedance components may be one or more capacitors, inductors, or both, and are selected so that each string is uniquely identifiable in the output signal resulting from the frequency-varying input signal. Numerical methods, such as non-linear regression, may then be used to resolve the resistance associated with each string.

Hall, A. Daniel (Inventor); Davies, Francis J. (Inventor)

2007-01-01

171

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

172

Particle-tracking investigation of the retention of sucker larvae emerging from spawning grounds in Upper Klamath Lake, Oregon  

USGS Publications Warehouse

This study had two objectives: (1) to use the results of an individual-based particle-tracking model of larval sucker dispersal through the Williamson River delta and Upper Klamath Lake, Oregon, to interpret field data collected throughout Upper Klamath and Agency Lakes, and (2) to use the model to investigate the retention of sucker larvae in the system as a function of Williamson River flow, wind, and lake elevation. This is a follow-up study to work reported in Wood and others (2014) in which the hydrodynamic model of Upper Klamath Lake was combined with an individual-based, particle-tracking model of larval fish entering the lake from spawning areas in the Williamson River. In the previous study, the performance of the model was evaluated through comparison with field data comprising larval sucker distribution collected in 2009 by The Nature Conservancy, Oregon State University (OSU), and the U.S. Geological Survey, primarily from the (at that time) recently reconnected Williamson River Delta and along the eastern shoreline of Upper Klamath Lake, surrounding the old river mouth. The previous study demonstrated that the validation of the model with field data was moderately successful and that the model was useful for describing the broad patterns of larval dispersal from the river, at least in the areas surrounding the river channel immediately downstream of the spawning areas and along the shoreline where larvae enter the lake. In this study, field data collected by OSU throughout the main body of Upper Klamath Lake, and not just around the Williamson River Delta, were compared to model simulation results. Because the field data were collected throughout the lake, it was necessary to include in the simulations larvae spawned at eastern shoreline springs that were not included in the earlier studies. A complicating factor was that the OSU collected data throughout the main body of the lake in 2011 and 2012, after the end of several years of larval drift collection in the Williamson River by the U.S. Geological Survey. Those larval drift data provided necessary boundary-condition information for the earlier studies, but there were no measured boundary conditions for larval input into model simulations during the years of this study (2011?12). Therefore, we developed a method to estimate a time series of larval drift in the Williamson River, and of the emergence of larvae from the gravel at the eastern shoreline springs, that captured the approximate timing of the larval pulse of the Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris) and the relative magnitude of the pulses by species and spawning location. The method is not able to predict larval drift on any given day, but it can reasonably predict the approximate temporal progression of the larval drift through the season, based on counts of adult suckers returning to spawn. The accuracy in the timing of the larval pulses is not better than about plus or minus 5 days. Model results and field data were consistent in the basic progression of both catch per unit effort (CPUE) and larval length through time. The model simulation results also duplicated some of the characteristics of the spatial patterns of density in the field data, notably the tendency for high larval densities closer to the eastern and western shorelines. However, the model simulations could not explain high densities in the northern part of the lake or far into Ball Bay, locations that are far from the source of larvae in the Williamson River or eastern shoreline springs (as measured along the predominant transport pathways simulated in the model). This suggests the possibility of unaccounted-for spawning areas in the northern part of the lake and also that the period during which larvae are transported passively by the currents is shorter than the 46 days simulated in the model. Similarly, the progression of larval lengths in the field data is not a simple progression from smaller to larger fish away from sources in the river and springs, as simulated by the parti

Wood, Tamara M.; Wherry, Susan A.; Simon, David C.; Markle, Douglas F.

2014-01-01

173

Cosmic string decay  

SciTech Connect

The authors calculate the rate of decay of cosmic string loops into fermions and bosons, at zero and non-zero temperatures, taking the back reaction of the string on itself into account. The decay rate is controlled by the radius of curvature of the string. They find that with the exception of decays into massless scalar fields at high temperatures, the decay rate is completely negligible for cosmologically interesting string loops, when compared to gravitational energy loss.

Brandenberger, R.; Matheson, A.

1987-07-01

174

Drill string enclosure  

DOEpatents

The drill string enclosure consists of six component parts, including; a top bracket, an upper acrylic cylinder, an acrylic drill casing guide, a lower acrylic cylinder, a bottom bracket, and three flexible ducts. The upper acrylic cylinder is optional based upon the drill string length. The drill string enclosure allows for an efficient drill and sight operation at a hazardous waste site.

Jorgensen, Douglas K. (Idaho Falls, ID); Kuhns, Douglass J. (Idaho Falls, ID); Wiersholm, Otto (Idaho Falls, ID); Miller, Timothy A. (Idaho Falls, ID)

1993-01-01

175

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

176

Drill string enclosure  

DOEpatents

The drill string enclosure consists of six component parts, including; a top bracket, an upper acrylic cylinder, an acrylic drill casing guide, a lower acrylic cylinder, a bottom bracket, and three flexible ducts. The upper acrylic cylinder is optional based upon the drill string length. The drill string enclosure allows for an efficient drill and sight operation at a hazardous waste site.

Jorgensen, D.K.; Kuhns, D.J.; Wiersholm, O.; Miller, T.A.

1993-03-02

177

[The string of Einthoven's string galvanometer].  

PubMed

The Dutch physiologist Willem Einthoven (1860-1927) published in 1901 his construction of a string galvanometer. With this apparatus he opened the era for electrocardiography. As the quality of his instrument largely depended on the string of the string galvanometer it is surprising to note that in his publications Einthoven never mentioned the exact way of producing the string. However, Einthoven's hand written laboratory notes are preserved at the Museum Boerhaave in Leiden. From these notes it comes clear what problems Einthoven had with the string. To get a very thin thread of quarts he first used the method of shooting the thread as was described by Boys (1887), later the blowing method of Nichols (1894). The silvering of the thread was done first chemically, later by cathode spray. In all cases premature breaking of the thread was a nuisance. Because of these failures Einthoven might have decided not to publish any details. PMID:11624925

Wyers, P J

1996-01-01

178

Review of haploporid (Trematoda) genera with ornate muscularisation in the region of the oral sucker, including four new species and a new genus.  

PubMed

Species of the Haploporidae Nicoll, 1914 with elaborate muscularisation of the oral sucker belong in three trematode genera, including three new species and a new genus from the intestine of fishes in Australian waters. Spiritestis Nagaty, 1948 is resurrected and S. herveyensis n. sp. is described from the mullet Moolgarda seheli (Forsskål) collected in Hervey Bay, Queensland, Australia; the latter differs from S. arabii Nagaty, 1948 in that the position of the genital pore is pharyngeal rather than post-pharyngeal and the geographical range is off Australia rather than the Red Sea. A new genus is proposed for two new species, with a uniquely ornamented oral sucker, which infect Australian scatophagids. Members of Capitimitta n. g. are distinguished from Waretrema Srivastava, 1937, species of which have a simple oral sucker with six radially arranged anterior muscular lobes, in that their oral sucker is V-shaped with six embedded muscular finger-like structures in the anteroventral portion. The relatively small C. darwinensis n. sp., collected from Selenotoca multifasciata (Richardson) at Darwin, Northern Territory, Australia, is distinguished from C. costata n. sp., collected from Scatophagus argus (Linnaeus) in the same locality and S. multifasciata off Brisbane, Australia, and by having smaller eggs, a vitellarium commencing at a level close to the ventral sucker rather than at greater than one ovarian length posterior to the ventral sucker, and shorter tegumental body spines. Sequence data of a c.2,500 bp region of the 3' end of 18S, the entire ITS region and the 5' end of the 28S revealed that Spiritestis and Capitimitta are not as closely related as some morphological features would suggest and are probably not the closest relative of each other. What has been reported as Waretrema piscicolum Srivastava, 1937 probably consists of several species, some in different genera, and one, based on material collected by Dr Masaaki Machida, is proposed as Spiritestis machidai n. sp. from Crenimugil crenilabis (Forsskål) off Japan. Phylogenetic hypotheses, based on analysis of an alignment of partial 28S sequences with other haploporids, provide a framework for the evaluation of interrelationships within the Haploporidae. These analyses show that: (1) Spiritestis and Capitimitta are supported within the Haploporidae; (2) branches to Forticulcita Overstreet, 1982, Saccocoelioides Szidat, 1954, Spiritestis and Capitimitta create a clade that is sister to haploporines from the Mediterranean Sea; (3) the branch to Saccocoelioides, Spiritestis and Capitimitta create a polytomy; and (4) the two new species of Capitimitta, plus an immature specimen of an unnamed species, form a monophyletic clade. PMID:23299754

Pulis, Eric E; Overstreet, Robin M

2013-02-01

179

Take it to the limit: The dynamics of rod load and rod reversal in reciprocating compressors  

SciTech Connect

A major factor the engineer must consider when designing a reciprocating compressor package is the structural limit of the compressor. This limit is referred to as the rod load or frame load and is the maximum continuous operating force the compressor can safely withstand. Our discussion will include static rod load, inertia rod load, dynamic rod load, and rod reversal, with guidelines for minimizing rod reversal in the field.

Gajjar, H.

1996-09-01

180

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

181

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

182

Survival of Lost River Suckers ( Deltistes luxatus ) Challenged with Flavobacterium columnare During Exposure to Sublethal Ammonia Concentrations at pH 9.5  

Microsoft Academic Search

The Lost River sucker (Deltistes luxatus) is a federally listed, endangered species inhabiting the hypereutrophic waters of Upper Klamath Lake in southern Oregon,\\u000a USA. High pH (?10) and elevated ammonia concentrations (?1 mg NH3-N\\/L) often occur during blooms of cyanobacteria (Aphanizomenon flos-aquae) in the lake, with major fish kills sometimes following a mid- or late-summer “crash” of the cyanobacterial population.

Jeffrey M. Morris; Elaine Snyder-Conn; J. Scott Foott; Richard A. Holt; Michael J. Suedkamp; Hilary M. Lease; Susan J. Clearwater; Joseph S. Meyer

2006-01-01

183

Assessment of larval deformities and selenium accumulation in northern pike (Esox lucius) and white sucker (Catostomus commersoni) exposed to metal mining effluent.  

PubMed

Uranium mining and milling operations in northern Saskatchewan (Canada) release effluents with elevated levels of certain trace metals and metalloids, including selenium. The goal of the present study was to evaluate the presence of selenium-induced deformities in northern pike (Esox lucius) and white sucker (Catostomus commersoni) larvae originating from adults collected downstream of a uranium mine. Eggs were fertilized in the field and incubated in the laboratory following a two-way (crossover) analysis-of-variance experimental design to discriminate effects from maternal transfer versus those from exposure to site water in the developing embryos. Selenium concentrations in northern pike and white sucker eggs (8.02 and 4.89 microg/g dry wt, respectively; mean +/- standard error throughout) from the exposure site were approximately two- to threefold higher than reference (2.35 +/- 0.20 and 1.94 +/- 0.25 microg/g dry wt, respectively). Among all evaluated deformities (skeletal curvatures, craniofacial deformities, fin deformities, and edema), only edema in white sucker fry from the exposure site was slightly elevated ( approximately 3%) compared to reference. The occurrence of edema, however, can be associated with factors other than selenium (e.g., other metals and organic compounds). Both fish species displayed strong linear relationships between the selenium concentrations in eggs and other tissues (muscle, liver, kidney, and bone), suggesting that selenium concentrations in eggs could be predicted from selenium concentrations in adult tissues. The lack of a clear, toxic response in the present study is in agreement with selenium thresholds for early life-stage deformities reported in other studies, with egg selenium concentrations in northern pike and white sucker collected at the exposure site being less than the 10 microg/g (dry wt) threshold associated with the presence of deformities. PMID:18939891

Muscatello, Jorgelina R; Janz, David M

2009-03-01

184

Comparative study of DNA adducts levels in white sucker fish ( Catostomus commersoni ) from the basin of the St. Lawrence River (Canada)  

Microsoft Academic Search

The levels of DNA adducts in the hepatic tissue of the white sucker fish speciesCatostomus commersoni were determined by32P-postlabelling. The fish were caught at four sites: two sites near the city of Windsor (Québec, Canada) on the St. François River, a downstream tributary of the St. Lawrence River, and two sites in the St. Lawrence River itself, near the city

C. Adlouni; J. Tremblay; P. Walsh; J. Lagueux; J. Bureau; D. Laliberte; G. Keith; D. Nadeau; G. G. Poirier

1995-01-01

185

Altered performance of white sucker populations in the Manitouwadge chain of lakes is associated with changes in benthic macroinvertebrate communities as a result of copper and zinc contamination.  

PubMed

White sucker (Catostomus commersoni) collected from the Manitouwadge chain of lakes show a lower growth rate and fecundity in lakes contaminated with copper and zinc from a mixed metal mine. This study evaluated whether the changes in performance of the fish were related to direct impacts of the metals or indirect impacts associated with changes in food availability. Concentrations of metals in the water and sediment of lakes in the Manitouwadge chain were elevated, relative to reference sites. The concentrations of Cu and Zn in the digesta of white sucker were significantly higher, as were the levels of both Cu and Zn in liver, kidney, and gill tissue. Muscle and spleen levels of Cu and Zn were significantly lower or not different from controls. Tissue levels were within the homeostatic range for Cu and Zn. However, the total density of invertebrates varied from greater than 25,000 m-2 at control sites to less than 13,000 m-2 at contaminated sites, and the number of genera recorded was more than 50% lower in shallow water samples. There was almost a complete absence of several invertebrate taxa at contaminated sites, including Plecoptera, Ephemeroptera, Odonata, Trichoptera, Amphipoda, and Unionidae. Diptera accounted for 78 to 96% of the total numbers of individuals at metal-contaminated sites as compared with 40 to 75% at the control sites. An analysis of white sucker stomach contents showed that the contents closely reflected the benthic composition observed in the natural substrate. Changes in food availability and feeding activity were correlated with previous changes documented in the growth, fecundity, and lipid levels of white sucker. PMID:1868788

Munkittrick, K R; Miller, P A; Barton, D R; Dixon, D G

1991-06-01

186

Survey of receiving-water environmental impacts associated with discharges from pulp mills; 3: Polychlorinated dioxins and furans in muscle and liver of white sucker (Catostomus commersoni)  

Microsoft Academic Search

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were measured in white sucker liver samples from seven pulp and paper mill sites, and three reference sites in Ontario. The mills included five bleached-kraft mills, with and without secondary treatment, and two sulfite-mechanical mills. 2,3,7,8-T[sub 4]CDD and 2,3,7,8-T[sub 4]CDF were the dominant congeners detected in both liver and fillet samples at all of

Mark R. Servos; Susan Y. Huestis; D. Michael Whittle; K. R. Munkittrick; G. J. Van Der Kraak

1994-01-01

187

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

PubMed

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 one of which was immunoreactive. The nonimmunoreactive cells contained dense-cored vesicles and long processes that extended between the immunoreactive cells and terminated at perivascular spaces. When corpuscle extracts were subjected to electrophoresis and Western blotting, three nonreduced stanniocalcin-like immunoreactive bands (approximately 56, 61, and 64 kDa) were observed. However, in the presence of a reductant, a diffuse band migrating in the range of 28 to 32 kDa was noted. The results of this study on the white sucker demonstrate the presence of a dimeric stanniocalcin-like molecule and present evidence of a previously uncharacterized cell-type in the corpuscles of Stannius. PMID:9634607

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

1998-07-01

188

String theory effective action; String loop corrections  

SciTech Connect

The authors discuss the general ideology of the computation of string loop corrections to the effective action for the massless modes of the string. Both the S-matrix and the sigma-model approaches are presented. It is emphasized that the effective action is more general and better defined object than the S-matrix. In particular, it is finite in spite of modular infinities that may be present in loop amplitudes computed near a wrong vacuum. The case of the disc topology in the open-closed string theory is treated in some detail. Some issues concerning the soft dilation vertex operators related to the infinities of the string amplitudes are discussed.

Tseytlin, A.A. (P.N. Lebedev Physical Institute, Leninsky pr 53, Moscow 117924 (SU))

1988-01-01

189

Stability of nonlinearly elastic rods  

Microsoft Academic Search

This paper describes previously unknown stabilities and instabilities of planar equilibrium configurations of a nonlinearly elastic rod that is buckled under the action of a dead-load. The governing equations are derived from variational principles, including ones of isoperimetric type. Properties of stability are accordingly determined by study of the second variation. Stabilities to deformations both in the plane and out

J. H. Maddocks; S. ANTMAN

1984-01-01

190

Cool Hot Rod (Thermal Expansion)  

NSDL National Science Digital Library

The phenomenon is thermal expansion of copper. This demonstration allows an observer to see the effect of heating (and cooling) a copper tube. When heated, the copper tube lengthens and thickens. When cooled, the tube shrinks. The lengthening of the rod rotates a toothpick with an attached flag to make the expansion visible and measurable.

191

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

192

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

193

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

194

Introduction to string theory  

NASA Astrophysics Data System (ADS)

This article is an introduction to string theory covering basic principles as well as advanced applications. The fundamental ideas behind string theory and how they are mathematically implemented is reviewed. The bosonic string is discussed and its problems are outlined. The five consistent superstring theories are introduced as well as their recently discovered relations through dualities. The black hole information paradox and how it is resolved by string theory is explained. There is also discussion about how ideas like holography and M-theory can lead us to physics beyond string theory. Finally, there is a brief review of the recent ideas of large extra dimensions that might lead to new possiblities for the experimental verification of string theory.

Danielsson, Ulf

2001-01-01

195

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

196

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

197

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

198

Minimal String Theory  

E-print Network

We summarize recent progress in the understanding of minimal string theory, focusing on the worldsheet description of physical operators and D-branes. We review how a geometric interpretation of minimal string theory emerges naturally from the study of the D-branes. This simple geometric picture ties together many otherwise unrelated features of minimal string theory, and it leads directly to a worldsheet derivation of the dual matrix model.

Nathan Seiberg; David Shih

2004-09-29

199

Axions from string decay  

SciTech Connect

We have studied numerically the evolution and decay of axion strings. These global defects decay mainly by axion emission and thus contribute to the cosmological axion energy density. The relative importance of this source relative to misalignment production of axions depends on the spectrum. Radiation spectra for various string loop configurations are presented. They support the contention that the string decay contribution is of the same order of magnitude as the contribution from misalignment.

Hagmann, C., LLNL

1998-07-09

200

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

201

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

202

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

203

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

204

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

205

String Theory Symmetries  

E-print Network

A brief review of the status of duality symmetries in string theory is presented. The evidence is accumulating rapidly that an enormous group of duality symmetries, including perturbative T dualities and non-perturbative S-dualities, underlies string theory. It is my hope that an understanding of these symmetries will suggest the right way to formulate non-perturbative string theory. Whether or not this hope is realized, it has already been demonstrated that this line of inquiry leads to powerful new tools for understanding gauge theories and new evidence for the uniqueness of string theory, as well as deep mathematical results.

John H. Schwarz

1995-03-20

206

String Theory and Duality  

E-print Network

This is a very brief survey of some results in the geometry of string duality delivered at a lecture given at ICM 1998, Berlin. String Duality is the statement that one kind of string theory compactified on one space is equivalent in some sense to another string theory compactified on a second space. This draws a connection between two quite different spaces. Mirror symmetry is an example of this. Here we discuss mirror symmetry and another ``heterotic/type II'' duality which relates vector bundles on a K3 surface to a Calabi-Yau threefold.

Paul S. Aspinwall

1998-09-01

207

STRING THEORY Problem Set # 10  

E-print Network

STRING THEORY Problem Set # 10 T-duality, of closed oriented string theories, compactified in one dimension on a circle o* *f radius R. Problem 1 Consider the closed oriented bosonic string on the space-time manifold M

208

Introduction to string field theory  

SciTech Connect

An action is proposed for an interacting closed bosonic string. Our formalism relies heavily on ideas discussed by Witten for the open bosonic string. The gauge fixed quantum action for the fully interacting open bosonic string is obtained.

Lykken, J.; Raby, S.

1986-01-01

209

Oxidative stress and endocrine endpoints in white sucker (Catostomus commersoni) from a river impacted by agricultural chemicals.  

PubMed

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 Québec (Canada). Plasma cholinesterase (ChE) activity, used as a biomarker of exposure to pesticides, was elevated in fish from the reference site compared to fish from the contaminated sites. Plasma concentrations of cortisol and thyroid hormones (T3 and T4) were higher in fish from the reference site compared to contaminated sites; reduced glutathione (GSH) levels, catalase (CAT), and glutathione peroxidase (GPx) activities were higher and lipid peroxidation (LPO) was lower. Levels of antioxidants (CAT, Gpx, and GSH) were higher (10-90%) and LPO levels were lower (50%) in the liver than in the adrenal tissue. The present in situ study provided evidence that antioxidants, lipid peroxidation, and plasma hormones were altered in fish sampled in areas impacted by agricultural chemicals. Endocrine-disrupting effects were associated with oxidative stress. The results suggest that antioxidants and lipid peroxidation could be used as markers of contaminant exposure in fish. PMID:16111011

Dorval, Jocelyn; Leblond, Vincent; Deblois, Christian; Hontela, Alice

2005-05-01

210

Single-phase convective heat transfer in rod bundles  

Microsoft Academic Search

The convective heat transfer for turbulent flow through rod bundles representative of nuclear fuel rods used in pressurized water reactors is examined. The rod bundles consist of a square array of parallel rods that are held on a constant pitch by support grids spaced axially along the rod bundle. Split-vane pair support grids, which create swirling flow in the rod

Mary V. Holloway; Donald E. Beasley; Michael E. Conner

2008-01-01

211

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

212

LOFT lead rod test results evaluation. [PWR  

SciTech Connect

The purpose for evaluating the LOFT Lead Rod Test (simulations of large break, loss-of-coolant accidents) data was to determine; (a) if the centerline thermocouple and fuel rod elongation sensor data show indications of the collapsed fuel rod cladding, (b) the capability of the FRAP-T5 computer code to accurately predict cladding collapse, and (c) if cladding surface thermocouples enhance fuel rod cooling. With consideration to unresolved questions on data integrity, it was concluded that: the fuel rod centerline thermocouple and elongation sensor data do show indications of the fuel rod cladding collapse; the FRAP-T5 code conservatively predicts cladding collapse; and there is an indication that cladding surface thermocouples are enhancing fuel rod cooling.

Driskell, W.B.; Tolman, E.L.

1980-07-30

213

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

214

Inflation in String Theory  

NASA Astrophysics Data System (ADS)

Recent developments in string theory such as flux compactifications and moduli stabilization by non-perturbative effects of D-branes provided a solid framework where we discuss the realization of inflation in string theories. We review two prototype models, modular inflation and brane inflation, and discuss their observational consequences and outlook.

Kim, Hang Bae

215

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.

Matt Vonk

216

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

217

Rotating String Shapes  

NSDL National Science Digital Library

In this group activity, learners make multi-sided polygons with string. Learners slide a long piece of string through their fingers to make different kinds of triangles (isosceles, right, equilateral, and scalene) and quadrilaterals, including concave and convex shapes. Learners also draw the shapes from different points of view to explore congruency.

Exploratorium

2010-01-01

218

Bosonic technicolor in strings  

NASA Astrophysics Data System (ADS)

It is shown that strings provide a natural theoretical setting for bosonic technicolor. In particular, bosonic technicolor structure arises in a class of strings formulated in four dimensions. An example of a model with three generations and multi-Higgs structure is presented.

Kagan, Alex; Samuel, Stuart

1992-06-01

219

Phase behavior of wormlike rods  

E-print Network

By employing Molecular Dynamics computer simulations, the phase behavior of systems of rodlike particles with varying degree of internal flexibility has been traced from the perfectly rigid rod limit till very flexible particles, and from the high density region till the isotropic phase. From the perfectly rigid rod limit and enhancing the internal flexibility, the range of the smectic A phase is squeezed out by the concomitant action of the scarcely affected crystalline phase at higher density and the nematic phase at lower density, until it disappears. These results confirm the supposition, drawn from previous theoretical, simulational and experimental studies, that the smectic A phase is destabilized by introducing and enhancing the degree of particle internal flexibility. However, no significant changes in the order of nematic--to--smectic A phase transition, which appears always first order, nor in the value of the layer spacing, are observed upon varying the degree of particle internal flexibility. Moreover, no evidence of a columnar phase, which was tought of as a possible superseder of the smectic A phase in flexible rods, has been obtained.

Giorgio Cinacchi; Luca De Gaetani

2007-11-12

220

Arto New String Calculator  

NSDL National Science Digital Library

Designed by a senior lecturer at the Department of Computer Science at the University of Helsinki in Finland, this website is a stand-alone Pascal program for string calculations. The idea came to him while visiting a French lute maker friend and the site has been continually updated since the original program was conceived. The calculator is useful only for calculating the tensions and diameters of strings made of homogenous material, thus wound strings, catlines and other such strings are excluded. The calculator is designed with lute instruments in mind but can be used for any stringed instrument: harpsichord, harp, guitar and pianos. The site provides easy to follow instructions and a glossary of the terms. Java 1.4 or 1.5 must be enabled to use this calculator.

Wikla, Arto

221

Stable Charged Cosmic Strings  

SciTech Connect

We study the quantum stabilization of a cosmic string by a heavy fermion doublet in a reduced version of the standard model. We show that charged strings, obtained by populating fermionic bound state levels, become stable if the electroweak bosons are coupled to a fermion that is less than twice as heavy as the top quark. This result suggests that extraordinarily large fermion masses or unrealistic couplings are not required to bind a cosmic string in the standard model. Numerically we find the most favorable string profile to be a simple trough in the Higgs vacuum expectation value of radius {approx_equal}10{sup -18} m. The vacuum remains stable in our model, because neutral strings are not energetically favored.

Weigel, H. [Physics Department, Stellenbosch University, Matieland 7602 (South Africa); Quandt, M. [Institute for Theoretical Physics, Tuebingen University, D-72076 Tuebingen (Germany); Graham, N. [Department of Physics, Middlebury College , Middlebury, Vermont 05753 (United States)

2011-03-11

222

Stable string bit models  

NASA Astrophysics Data System (ADS)

In string bit models, the superstring emerges as a very long chain of "bits," in which s fermionic degrees of freedom contribute positively to the ground state energy in a way to exactly cancel the destabilizing negative contributions of d=s bosonic degrees of freedom. We propose that the physics of string formation be studied nonperturbatively in the class of string bit models in which s>d, so that a long chain is stable, in contrast to the marginally stable (s=d=8) superstring chain. We focus on the simplest of these models with s=1 and d=0, in which the string bits live in zero space dimensions. The string bit creation operators are N×N matrices. We choose a Hamiltonian such that the large N limit produces a string moving in one space dimension, with excitations corresponding to one Grassmann light-cone world sheet field (s=1) and no bosonic world sheet field (d=0). We study this model at finite N to assess the role of the large N limit in the emergence of the spatial dimension. Our results suggest that stringlike states with large bit number M may not exist for N?(M-1)/2. If this is correct, one can have finite chains of string bits, but not a continuous string, at finite N. Only for extremely large N can such chains behave approximately like a continuous string, in which case there will also be the (approximate) emergence of a new spatial dimension. In string bit models designed to produce a critical superstring at N=?, we can then expect only approximate Lorentz invariance at finite N, with violations of order 1/N2.

Sun, Songge; Thorn, Charles B.

2014-05-01

223

Arenas for String Phenomenology String Phenomenology 2011, Madison  

E-print Network

Arenas for String Phenomenology String Phenomenology 2011, Madison Michael Dine Department of Physics University of California, Santa Cruz August, 2011 Michael Dine Arenas for String Phenomenology #12;Possible Arenas for a String Phenomenology 1 Hierarchy problem: LHC scale physics: supersymmetry, RS, large

California at Santa Cruz, University of

224

Closed String Cohomology in Open String Field Theory  

E-print Network

We show that closed string states in bosonic string field theory are encoded in the cyclic cohomology of cubic open string field theory (OSFT) which, in turn, classifies the deformations of OSFT. This cohomology is then shown to be independent of the open string background. Exact elements correspond to closed string gauge transformations, generic boundary deformations of Witten's 3-vertex and infinitesimal shifts of the open string background. Finally it is argued that the closed string cohomology and the cyclic cohomology of OSFT are isomorphic to each other.

Nicolas Moeller; Ivo Sachs

2010-10-20

225

Fusing E-strings to heterotic strings: E +E ?H  

NASA Astrophysics Data System (ADS)

E-strings arise from M2 branes suspended between an M5 brane and an M9 plane. In this paper we obtain explicit expressions for the elliptic genus of two E-strings using a series of string dualities. Moreover we show how this can be used to recover the elliptic genus of two E8×E8 heterotic strings using the Ho?ava-Witten realization of heterotic strings in M-theory. This involves highly nontrivial identities among Jacobi forms and is remarkable in light of the fact that E-strings are "sticky" and form bound states whereas heterotic strings do not form bound states.

Haghighat, Babak; Lockhart, Guglielmo; Vafa, Cumrun

2014-12-01

226

The Rod Photoreceptor Lineage of Teleost Fish  

PubMed Central

The retinas of postembryonic teleost fish continue to grow for the lifetime of the fish. New retinal cells are added continuously at the retinal margin, by stem cells residing at the circumferential germinal zone. Some of these retinal cells differentiate as Müller glia with cell bodies that reside within the inner nuclear layer. These glia retain some stem cell properties in that they carry out asymmetric cell divisions and continuously generate a population of transit-amplifying cells – the rod photoreceptor lineage – that are committed to rod photoreceptor neurogenesis. These rod progenitors progress through a stereotyped sequence of changes in gene expression as they continue to divide and migrate to the outer nuclear layer. Now referred to as rod precursors, they undergo terminal mitoses and then differentiate as rods, which are inserted into the existing array of rod and cone photoreceptors. The rod lineage displays developmental plasticity, as rod precursors can respond to the loss of rods through increased proliferation, resulting in rod replacement. The stem cells of the rod lineage, Müller glia, respond to acute damage of other retinal cell types by increasing their rate of proliferation. In addition, the Müller glia in an acutely damaged retina dedifferentiate and become multipotent, generating new, functional neurons. This review focuses on the cells of the rod lineage and includes discussions of experiments over the last 30 years that led to their identification and characterization, and the discovery of the stem cells residing at the apex of the lineage. The plasticity of cells of the rod lineage, their relationships to cone progenitors, and the applications of this information for developing future treatments for human retinal disorders will also be discussed. PMID:21742053

Stenkamp, Deborah L.

2011-01-01

227

QCD String as Vortex String in Seiberg-Dual Theory  

E-print Network

We construct a classical vortex string solution in a Seiberg-dual theory of N=1 supersymmetric SO(N_c) QCD which flows to a confining phase. We claim that this vortex string is a QCD string, as previouly argued by M.Strassler. In SO(N_c) QCD, it is known that stable QCD strings exist even in the presence of dynamical quarks. We show that our vortex strings are stable in the Seiberg-dual theory.

Minoru Eto; Koji Hashimoto; Seiji Terashima

2007-06-14

228

Endocrine changes during natural spawning in the white sucker, Catostomus commersoni. I. Gonadotropin, growth hormone, and thyroid hormones.  

PubMed

White suckers (Catostomus commersoni; Cypriniformes, Teleosteii) spawning in a small stream in central Alberta were captured during different stages of their spawning migrations in 1981 and 1982, blood was sampled, and the fish were examined to determine their reproductive condition. Blood samples were analyzed for gonadotropin (GtH), growth hormone (GH), triiodothyronine (T3), and thyroxine (T4) by radioimmunoassay. GtH levels in both sexes were lowest prior to the onset of spawning, increased significantly in spawning males, females in which germinal vesicle migration had begun, and ovulated females and then dropped significantly in spent fish of both sexes. GH was lowest in prespawning females, increased significantly at ovulation, and remained high in spent females. In contrast, GH levels in males were relatively constant throughout spawning. In both sexes, highest T4 levels were found in prespawning fish, and T4 decreased significantly in spent fish. Although a similar decline was seen in T3 in 1981, in 1982 there were no T3 changes associated with changes in reproductive condition. No significant diurnal variations were detected in the levels of GtH or T3; T4 levels appeared to vary on a diurnal basis in prespawning males only. Spawning activity in both sexes therefore appears to be associated with increases in GtH occurring at ovulation in females and at the initiation of spawning in males. GH levels may also be related to reproductive condition in females, but not in males. The relationship of thyroid hormone levels to reproductive condition is less clear, however, and these levels may reflect both endocrine and environmental influences on thyroid function. PMID:6510693

Stacey, N E; MacKenzie, D S; Marchant, T A; Kyle, A L; Peter, R E

1984-12-01

229

NUPlans Web Chart String Maintenance  

E-print Network

NUPlans Web Chart String Maintenance Job Aid NUPlansChartStringMaintV1.1 Last Updated 4/14/2013 - mac © 2013 Northwestern University FMS705 NUPlans Web 1 of 3 Chart String Maintenance in NUPlans Web. This job aid helps you understand and complete tasks related to chart string maintenance in NUPlans Web

Shull, Kenneth R.

230

Minimum Common String Partition Parameterized  

E-print Network

Minimum Common String Partition Parameterized Peter Damaschke Department of Computer Science and Engineering Chalmers University, 41296 G¨oteborg, Sweden ptr@cs.chalmers.se Abstract. Minimum Common String occurences in x. In the Minimum Common String Partition (MCSP) problem, two strings x, y of length n

Damaschke, Peter

231

Swiftly Computing Center Strings  

PubMed Central

Background The center string (or closest string) problem is a classic computer science problem with important applications in computational biology. Given k input strings and a distance threshold d, we search for a string within Hamming distance at most d to each input string. This problem is NP complete. Results In this paper, we focus on exact methods for the problem that are also swift in application. We first introduce data reduction techniques that allow us to infer that certain instances have no solution, or that a center string must satisfy certain conditions. We describe how to use this information to speed up two previously published search tree algorithms. Then, we describe a novel iterative search strategy that is effecient in practice, where some of our reduction techniques can also be applied. Finally, we present results of an evaluation study for two different data sets from a biological application. Conclusions We find that the running time for computing the optimal center string is dominated by the subroutine calls for d = dopt -1 and d = dopt. Our data reduction is very effective for both, either rejecting unsolvable instances or solving trivial positions. We find that this speeds up computations considerably. PMID:21504573

2011-01-01

232

Fuel rod retention device for a nuclear reactor  

DOEpatents

A device is described for supporting a nuclear fuel rod in a fuel rod assembly which allows the rod to be removed without disturbing other rods in the assembly. A fuel rod cap connects the rod to a bolt which is supported in the assembly end fitting by means of a locking assembly. The device is designed so that the bolt is held securely during normal reactor operation yet may be easily disengaged and the fuel rod removed when desired.

Hylton, Charles L. (Madison Heights, VA)

1984-01-01

233

String Field Theory  

NASA Astrophysics Data System (ADS)

String theory has emerged as the leading candidate for a unified field theory of all known forces. However, it is impossible to trust the various phenomenological predictions of superstring theory based on classical solutions alone. It appears that the crucial problem of the theory, breaking ten dimensional space-time down to four dimensions, must be solved nonperturbatively before we can extract reliable predictions. String field theory may be the only formalism in which we can resolve this decisive question. Only a rigorous calculation of the true vacuum of the theory will determine which of the many classical solutions the theory actually predicts. In this review article, we summarize the rapid progress in constructing string field theory actions, such as the development of the covariant BRST theory. We also present the newer geometric formulation of string field theory, from which the BRST theory and the older light cone theory can be derived from first principles. This geometric formulation allows us to derive the complete field theory of strings from two geometric principles, in the same way that general relativity and Yang-Mills theory can be derived from two principles based on global and local symmetry. The geometric formalism therefore reduces string field theory to a problem of finding an invariant under a new local gauge group we call the universal string group (USG). Thus, string field theory is the gauge theory of the universal string group in much the same way that Yang-Mills theory is the gauge theory of SU(N). Thus, the geometric formulation places superstring theory on the same rigorous group theoretical level as general relativity and gauge theory.

Kaku, Michio

234

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

235

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

236

Integrability in String Theories  

E-print Network

The solution term by term to the scattering of all consistent string theories is given. The moduli space of M-theory is derived and connects the various string theories. The solutions contain both the perturbative and non-perturbative sectors of the string. Modular forms found by differential equations on subspaces of the M-theory moduli space and transfinite algebras play an essential role in deriving the coefficients. Various results and identities in algebra are found from the explicit solution. Archetypes and models are presented in accord with phenomenology and cosmology.

Gordon Chalmers

2006-04-03

237

Dissipative String Fluids  

E-print Network

Systems of interacting networks of strings such as cosmic strings or quantum vortices can be approximated in a certain regime as an anisotropic fluid with an equation of state depending on a conserved flux. The equations for ideal magnetohydrodynamics are shown to be another example of a fluid of this type. Previous work on these fluids is now extended to include dissipative effects. The new dissipative terms are discussed in terms of both standard resistive magnetohydrodynamics and small-scale structure formation in networks of cosmic strings. The requirement of frame invariance is shown to restrict the form of higher order corrections to heat flow in the anisotropic direction.

Daniel Schubring

2014-12-09

238

Rod hue biases produced on CRT displays.  

PubMed

Studies of rod hue biases using monochromatic stimuli have shown that rod stimulation can shift the balance of hues at mesopic light levels. We found that the CRT display produced all three previously identified rod hue biases, which shifted the loci of all four unique hues at low mesopic light levels. Rod hue biases occurred at 2.6 cd/m(2) for some observers but not at 26 cd/m(2). At optimal light levels below 0.5 cd/m(2), rod hue biases varied among observers but generally (1) enhanced green versus red at unique yellow and sometimes at unique blue, (2) enhanced blue versus yellow at both unique green and unique red, and (3) enhanced red versus green at unique blue. Rod hue biases persisted for some observers even for smaller foveal stimuli. PMID:22330401

Buck, Steven L; Juve, Ryan; Wisner, David; Concepcion, Aldebert

2012-02-01

239

Reactor control rod timing system. [LMFBR  

DOEpatents

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 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, P.T.K.

1980-03-18

240

Influences of chronic cholangiohepatitis and cholestasis on hepatic metabolism of benzo[a]pyrene in white suckers (Catostomus commersoni) from industrially polluted areas of Lake Ontario.  

PubMed

White suckers from polluted regions of western Lake Ontario have an increased prevalence of cholangiocellular and hepatocellular and hepatocellular neoplasms associated with an idiopathic chronic cholangiohepatitis. We examined the hypothesis that bile duct obstructions and cholestasis in these fish might increase the susceptibility of liver to administered benzo[a]pyrene (B[a]P). Cytosolic glutathione S-transferase (GST) activity (CDNB) was reduced in obstructed liver to 45% of activity in adjacent unobstructed liver. At micromolar concentrations, chenodeoxycholic acid, deoxycholic acid, bilirubin and haematin each inhibited GST activity of hepatic cytosolic and S-hexylglutatione-affinity-purified GST preparations from unobstructed liver. Liver cytosol and affinity-purified hepatic GSTs from normal white sucker liver reduced DNA binding of 3H-benzo[a]-pyrene-7,8-diol-9,10-epoxide (3H-BPDE) after preincubation in vitro in the presence of 5 mM GSH. Under these conditions, cytosol from adjacent unobstructed liver had a moderately stronger protective activity against DNA binding by BPDE (16.4 +/- 1.3 pmol BPDE/mg DNA) than did cytosol from obstructed liver (20.6 +/- 1.6 pmol BPDE/mg DNA). Suckers with obstructed livers identified by laparotomy were orally administered 3H-benzo[a]pyrene (3H-B[a]P) (0.2 mmol/kg) or unlabelled B[a]P (2.0 mg/kg) and the level of B[a]P macromolecular binding was analyzed in liver tissue by liquid scintillation counting and by immunohistochemistry with antibodies to BPDE-DNA adducts. Covalent binding of 3H-B[a]P to hepatic protein was 30% less in adjacent unobstructed liver compared to obstructed liver; however, there was no significant difference in the levels of 3H-B[a]P bound to DNA in the obstructed lobes compared with non-obstructed adjacent liver. These studies demonstrate that some endogenous non-substrate ligands that accumulate during cholestasis can reduce hepatic GST activity in white suckers. While these changes are insufficient to influence total 3H-B[a]P-DNA adducts in obstructed liver, the preferential localization of BPDE-DNA adducts in GST-deficient hyperplastic biliary tracts suggests that cholangiohepatitis might increase susceptibility to cholangiolar neoplasia in fish exposed to genotoxic polycyclic aromatic hydrocarbons. PMID:8603465

Kirby, G M; Stalker, M J; Gordon, S; Quinn, B A; van Schooten, F J; Hayes, M A

1995-12-01

241

Tethered Rod Smectic C phase  

NSDL National Science Digital Library

Simulation Software: Glotzer Group Code Simulation Method: Brownian Dynamics A system of 800 building blocks of composition rod5b-tether6b at a concentration of 0.20, was run starting at a temperature of effecitvely infinite then instantaneously quenched to a temperature of 1.0. The system was then run for 3,000,000 time steps forming a Smetic C phase.The solve was selective for the neutral Simulation Model: United Atom Bead Spring with Lennard-Jones and FENE

Zhang, Zhenli

2005-01-31

242

Impact of AD995 alumina rods  

Microsoft Academic Search

Gas guns and velocity interferometric techniques have been used to determine the loading behavior of AD995 alumina rods 19 mm in diameter by 75 mm and 150 mm long, respectively. Graded-density materials were used to impact both bare and sleeved alumina rods while the velocity interferometer was used to monitor the axial-velocity of the free end of the rods. Results

L. C. Chbabildas; M. D. Furnish; W. D. Reinhart; D. E. Grady

1998-01-01

243

Impact of AD995 Alumina Rods  

Microsoft Academic Search

Gas gun experiments combined with velocity interferometric techniques have been used to determine the loading behavior of an AD995 alumina rod 19mm in diameter by 75mm and 150mm long, respectively. Graded-density materials were used to impact both bare and sleeved alumina rods, while the velocity interferometer was used to monitor the axial-velocity of the free end of the rods. Results

L. C. Chhabildas; M. D. Furnish; W. D. Reinhart; D. E. Grady

1997-01-01

244

Temperature actuated automatic safety rod release  

DOEpatents

A temperature-actuated apparatus is disclosed for releasably supporting a safety rod in a nuclear reactor, comprising a safety rod upper adapter having a retention means, a drive shaft which houses the upper adapter, and a bimetallic means supported within the drive shaft and having at least one ledge which engages a retention means of the safety rod upper adapter. A pre-determined increase in temperature causes the bimetallic means to deform so that the ledge disengages from the retention means, whereby the bimetallic means releases the safety rod into the core of the reactor.

Hutter, E.; Pardini, J.A.; Walker, D.E.

1984-03-13

245

Temperature actuated automatic safety rod release  

DOEpatents

A temperature-actuated apparatus is disclosed for releasably supporting a safety rod in a nuclear reactor, comprising a safety rod upper adapter having a retention means, a drive shaft which houses the upper adapter, and a bimetallic means supported within the drive shaft and having at least one ledge which engages a retention means of the safety rod upper adapter. A pre-determined increase in temperature causes the bimetallic means to deform so that the ledge disengages from the retention means, whereby the bimetallic means releases the safety rod into the core of the reactor.

Hutter, Ernest (Wilmette, IL); Pardini, John A. (Brookfield, IL); Walker, David E. (Naperville, IL)

1987-01-01

246

Growth and Morphology of Rod Eutectics  

SciTech Connect

The formation of rod eutectic microstructure is investigated systematically in a succinonitrile-camphor alloy of eutectic composition by using the directional solidification technique. A new rod eutectic configuration is observed in which the rods form with elliptical cylindrical shape. Two different orientations of the ellipse are observed that differ by a 90{sup o} rotation such that the major and the minor axes are interchanged. Critical experiments in thin samples, where a single layer of rods forms, show that the spacing and orientation of the elliptic rods are governed by the growth rate and the sample thickness. In thicker samples, multi layers of rods form with circular cross-section and the scaling law between the spacing and velocity predicted by the Jackson and Hunt model is validated. A theoretical model is developed for a two-dimensional array of elliptical rods that are arranged in a hexagonal or a square array, and the results are shown to be consistent with the experimental observations. The model of elliptic rods is also shown to reduce to that for the circular rod eutectic when the lengths of the two axes are equal, and to the lamellar eutectic model when one of the axes is much larger than the other one.

Jing Teng; Shan Liu; R. Trivedi

2008-03-17

247

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

248

Subsurface drill string  

DOEpatents

A drill string comprises a first drill string member having a male end; and a second drill string member having a female end configured to be joined to the male end of the first drill string member, the male end having a threaded portion including generally square threads, the male end having a non-threaded extension portion coaxial with the threaded portion, and the male end further having a bearing surface, the female end having a female threaded portion having corresponding female threads, the female end having a non-threaded extension portion coaxial with the female threaded portion, and the female end having a bearing surface. Installation methods, including methods of installing instrumented probes are also provided.

Casper, William L. (Rigby, ID); Clark, Don T. (Idaho Falls, ID); Grover, Blair K. (Idaho Falls, ID); Mathewson, Rodney O. (Idaho Falls, ID); Seymour, Craig A. (Idaho Falls, ID)

2008-10-07

249

string-lib.scm  

E-print Network

The core ;;; calculation that you don't want to overflow is, worst case, ;;; (+ 65535 ... cause this expression to fixnum overflow, ;;; and everything will be copacetic. ...... (list delim)))) (else (error "Illegal join grammar" grammar string-join))))) ((eq?

250

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

251

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

252

String Theory and Cosmology  

E-print Network

We discuss the main cosmological implications of considering string-loop effects and a potential for the dilaton in the lowest order string effective action. Our framework is based on the effective model arising from regarding homogeneous and isotropic dilaton, metric and Yang-Mills field configurations. The issues of inflation, entropy crisis and the Polonyi problem as well as the problem of the cosmological constant are discussed.

M. C. Bento; O. Bertolami

1995-05-22

253

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

254

Optimization of Single-Photon Response Transmission at the Rod-to-Rod Bipolar Synapse  

NSDL National Science Digital Library

Our ability to see in dim light is limited by the statistics of light absorption in rod photoreceptors and the faithful transmission of the light-evoked signals through the retina. This article reviews the physiological mechanisms at the synapse between rods and rod bipolar cells, the first relay in a pathway that mediates vision near absolute threshold.

2007-08-01

255

A Universal w String Theory  

E-print Network

It has been shown that there is a sequential embedding structure in a $w_N$\\ string theory based on a linearized $W_N$\\ algebra. The $w_N$\\ string theory is obtained as a special realization of the $w_{N+1}$\\ string. The $w_{\\infty}$\\ string theory is a universal string theory in this sense. We have also shown that there is a similar sequence for $N=1$\\ string theory. The $N=1\\ w_N$\\ string can be given as a special case of the $N=1\\ w_{N+1}$\\ string. In addition, we show that the $w_3$\\ string theory is obtained as a special realization of the $N=1\\ w_3$\\ string. We conjecture that the $w_N$\\ string can be obtained as a special $N=1\\ w_N$\\ string for general $w_N$. If this is the case, $N=1\\ w_{\\infty}$\\ string theory is more universal since it includes both $N=0$\\ and $N=1$\\ $w_N$\\ string theories.

Hiroshi Kunitomo; Makoto Sakaguchi; Akira Tokura

1994-03-22

256

Evidence for a maternal yolk factor associated with increased tolerance and resistance of feral white sucker (Catostomus commersoni) to waterborne copper.  

PubMed

White suckers, collected from lakes containing elevated levels of copper (12 micrograms liter-1) and zinc (250 micrograms liter-1), were evaluated for reproductive performance, growth and survival of the larvae, and tolerance of the larvae to waterborne copper. Fertilization success was not impaired in white suckers from contaminated sites; metal-exposed males performed better than control males in fertilization trials with control eggs. Larvae hatched from eggs collected at contaminated sites and fertilized in clean water were smaller, developed at a slightly increased rate, and exhibited poorer growth and survival than larvae from control sites. Larvae showed significant changes in resistance and tolerance to copper with age. During the period of endogenous nutrition, larvae from eggs taken at contaminated sites showed increased resistance and tolerance to waterborne copper relative to controls. The effect was not seen in larvae at first feeding, at ages older than 4 days after the onset of feeding (25 days posthatch) or in larvae hatched from control eggs fertilized with sperm from males taken at contaminated sites. This study provides evidence for a maternal yolk factor associated with increased tolerance and resistance of larvae to copper. PMID:3359958

Munkittrick, K R; Dixon, D G

1988-02-01

257

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.  

PubMed

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 benefit of these changes have not been looked at in wild fish. Jackfish Bay white sucker showed impacts on sexual maturity, gonad size, secondary sexual characteristics and circulating steroids hormone levels in the early years of the studies, and impacts were evaluated after installation of secondary treatment (1989), major pulping process changes (1995) and after the mill ceased pulp production and effluent release (2006). The addition of secondary treatment resulted in minor improvements in wild fish health, and the conversion to elemental chlorine free (ECF) bleaching at the mill was associated with more recovery in liver and gonad size. While some impacts persist at the exposure site, reproductive parameters showed further improvement during the mill shutdown period demonstrating that biologically active chemicals are still being discharged from modernized mills. PMID:19783055

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

2009-11-01

258

Effects of photoperiod and temperature on rhythmic melatonin secretion from the pineal organ of the white sucker (Catostomus commersoni) in vitro.  

PubMed

The secretion rate of melatonin from cultured pineal organs of the white sucker was examined for several days under either a 12:12-hr light:dark (LD) cycle or continuous darkness (DD) at either 10 degrees or 20 degrees. The incubation medium was changed at 3-hr intervals and secreted melatonin was measured by RIA. Under a 12:12-hr LD cycle (0800 light on, 2000 light off) melatonin secretion was suppressed during the day and highly active at night, with larger amplitudes at 20 than at 10 degrees. In DD at 10 degrees no circadian rhythmicity in secretion was found in October or January, whereas at 20 degrees a circadian-like pattern was detected in pineals which were derived from animals reared at either 10 degrees or 20 degrees for 1 week prior to the experiment in October or January. The pineals in the DD experiment still responded to an additional 24-hr LD cycle at both temperatures even after 6 or more days. These results clearly reveal the influence of photoperiod and temperature on melatonin secretion of organ-cultured pineal glands. The existence of a circadian oscillator for melatonin secretion in the pineal gland of the white sucker is suggested. PMID:1505727

Zachmann, A; Falcon, J; Knijff, S C; Bolliet, V; Ali, M A

1992-04-01

259

Comparative study of DNA adducts levels in white sucker fish (Catostomus commersoni) from the basin of the St. Lawrence River (Canada).  

PubMed

The levels of DNA adducts in the hepatic tissue of the white sucker fish species Catostomus commersoni were determined by 32P-postlabelling. The fish were caught at four sites: two sites near the city of Windsor (Québec, Canada) on the St. François River, a downstream tributary of the St. Lawrence River, and two sites in the St. Lawrence River itself, near the city of Montréal (Québec, Canada). The latter sites are known to be contaminated by many pollutants including polycyclic aromatic hydrocarbons. Total adduct levels in all fish ranged from 25.1-178.0 adducts per 10(9) nucleotides. White sucker from the selected sites of the St. Lawrence River had a significantly higher mean level of DNA adducts than those of the St. François River (129.4 vs 56.8, respectively). These results suggest that the effluents of many heavy industries (e.g. from a Soderberg aluminium plant) flowing in the St. Lawrence River are more likely to produce genotoxic damage to fish than those released in one of its tributary, and mainly associated to the activities of a small town and a nearby pulp and paper mill. PMID:8594417

el Adlouni, C; Tremblay, J; Walsh, P; Lagueux, J; Bureau, J; Laliberte, D; Keith, G; Nadeau, D; Poirier, G G

1995-07-19

260

Hands On Math Using Colored Rods.  

ERIC Educational Resources Information Center

Students enjoy learning by doing and by manipulating objects. This paper describes classroom activities using rods with various lengths and different colors. The activities included are: (1) preparation of rods; (2) elementary addition and subtraction; (3) fractions; (4) concept of greater than, less than, and equals; (5) simple division and…

Barry, Dana Malloy

261

Joule heating of a titanium rod  

NSDL National Science Digital Library

Use the steady-state heat conduction solution for constant heat generation in a rod to determine the maximum temperature difference between the center and surface of a titanium rod heated by electric current; also sketch temperature history from the time when current is turned on.

Powell, Adam C., IV

2002-10-04

262

Tipping Time of a Quantum Rod  

ERIC Educational Resources Information Center

The behaviour of a quantum rod, pivoted at its lower end on an impenetrable floor and restricted to moving in the vertical plane under the gravitational potential, is studied analytically under the approximation that the rod is initially localized to a "small-enough" neighbourhood around the point of classical unstable equilibrium. It is shown…

Parrikar, Onkar

2010-01-01

263

SATURATION AND ADAPTATION IN THE ROD SYSTEM  

Microsoft Academic Search

A background that is briefly flashed to a dark-adapted eye saturates the rod system. This transient saturation occurs with backgrounds that are as much as 2 log units dimmer than those producing saturation under steady viewing. Rod threshold is highest when the background is first turned on, and falls as adaptation proceeds. The nature of the adaptive processes are studied

Edward H. Adelson

264

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

265

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

266

Rod-Coil Block Polyimide Copolymers  

NASA Technical Reports Server (NTRS)

This invention is a series of rod-coil block polyimide copolymers that are easy to fabricate into mechanically resilient films with acceptable ionic or protonic conductivity at a variety of temperatures. The copolymers consist of short-rigid polyimide rod segments alternating with polyether coil segments. The rods and coil segments can be linear, branched or mixtures of linear and branched segments. The highly incompatible rods and coil segments phase separate, providing nanoscale channels for ion conduction. The polyimide segments provide dimensional and mechanical stability and can be functionalized in a number of ways to provide specialized functions for a given application. These rod-coil black polyimide copolymers are particularly useful in the preparation of ion conductive membranes for use in the manufacture of fuel cells and lithium based polymer batteries.

Meador, Mary Ann B. (Inventor); Kinder, James D. (Inventor)

2005-01-01

267

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.

2014-12-01

268

Space from string bits  

NASA Astrophysics Data System (ADS)

We develop superstring bit models, in which the lightcone transverse coordinates in D spacetime dimensions are replaced with d = D -2 double-valued "flavor" indices x k ? f k = 1 , 2; k = 2 , . . . , d + 1. In such models the string bits have no space to move. Let-ting each string bit be an adjoint of a "color" group U( N), we then analyze the physics of 't Hooft's limit N ? ?, in which closed chains of many string bits behave like free lightcone IIB superstrings with d compact coordinate bosonic worldsheet fields x k , and s pairs of Grassmann fermionic fields ? {/L, R a }, a = 1 , . . . , s. The coordinates x k emerge because, on the long chains, flavor fluctuations enjoy the dynamics of d anisotropic Heisenberg spin chains. It is well-known that the low energy excitations of a many-spin Heisenberg chain are identical to those of a string worldsheet coordinate compactified on a circle of radius R k , which is related to the anisotropy parameter -1 ? ? k ? 1 of the corresponding Heisenberg system. Furthermore there is a limit of this parameter, ? k ? ±1, in which R k ? ?. As noted in earlier work [ Phys. Rev. D 89 (2014) 105002], these multi-string-bit chains are strictly stable at N = ? when d < s and only marginally stable when d = s. (Poincaré supersymmetry requires d = s = 8, which is on the boundary between stability and instability.)

Thorn, Charles B.

2014-11-01

269

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

270

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

271

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

272

Simplicial Aspects of String Dualities  

SciTech Connect

We show how the study of randomly triangulated surfaces merges with the study of open/closed string dualities. In particular, we discuss the Conformal Field Theory which arises in the open string sector and its implications.

Carfora, Mauro; Dappiaggi, Claudio; Gili, Valeria [Dipartimento di Fisica Nucleare e Teorica, Universita degli Studi di Pavia, Sezione di Pavia, via A. Bassi 6, I-27100 Pavia (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, via A. Bassi 6, I-27100 Pavia (Italy)

2005-03-16

273

Cosmic Strings Lens Phenomenology Revisited  

E-print Network

We present investigations of lens phenomenological properties of cosmic strings for deep galaxy surveys. General results that have obtained for lineic energy distribution are presented first. We stress that generically the local convergence always vanishes in presence of strings although there might be some significant distortions. We then propose a simplified model of strings, we call ``Poisson strings'', for which exhaustive investigations can be done either numerically or analytically.

Francis Bernardeau; Jean-Philippe Uzan

2000-08-09

274

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

275

Racetrack Inflation and Cosmic Strings  

E-print Network

We consider the coupling of racetrack inflation to matter fields as realised in the D3/D7 brane system. In particular, we investigate the possibility of cosmic string formation in this system. We find that string formation before or at the onset of racetrack inflation is possible, but they are then inflated away. Furthermore, string formation at the end of inflation is prevented by the presence of the moduli sector. As a consequence, no strings survive racetrack inflation.

Philippe Brax; Carsten van de Bruck; Anne-Christine Davis; Stephen C. Davis; Rachel Jeannerot; Marieke Postma

2008-05-09

276

String from Veneziano model  

E-print Network

This article is about my memories from the discovery that the Veneziano model describes in fact interacting strings. I came to the understanding of that the dual or Veneziano model is really a model of strings independently of L. Susskind and Y. Nambu. A characteristic feature of my approach was that I used thinking of very high order "fishnet" or planar Feynman diagrams as the way of at first describing the development of the strings. A chain of constituents leads to planar diagrams dominating when only neighbours on the chain interact significantly. The article also mentions the works of Ziro Koba and mine about extending the Veneziano model first to five external particles - as Bardakci and Ruegg, Chan Tsou, and Goebel and Sakita also did - and subsequently to an arbitrary number n of external mesons.

H. B. Nielsen

2009-04-27

277

String Theory and Quark Confinement  

E-print Network

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.

A. Polyakov

1997-11-01

278

STRING THEORY Problem Set # 10  

E-print Network

STRING THEORY Problem Set # 10 April 10, 1997 In the following problems, we shall derive certain properties, under so­called T­duality, of closed oriented string theories, compactified in one dimension on a circle of radius R. Problem 1 Consider the closed oriented bosonic string on the space­time manifold M

279

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

280

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

281

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

282

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 Planck or string scale. Such strings cluster in a manner similar to dark matter leading to hugely enhanced densities. As a result, numerous fossil remnants of the low tension cosmic strings may exist within the galaxy. They can be revealed through the optical lensing of background stars in the near future and studied in detail through gravitational wave emission. We anticipate that these cosmic strings will permit us to address central questions about the properties of string theory as well as the birth of our universe.

David F. Chernoff; S. -H. Henry Tye

2014-12-01

283

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

284

Strings, standing waves and harmonics  

NSDL National Science Digital Library

This website from the University of New South Wales contains basic information about how stringed instruments produce sound. The site discusses plucked string sound and bowed string sound, standing waves, and harmonics. There are many helpful animations and pictures to illustrate concepts.

Wolfe, Joe

2009-11-16

285

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

286

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

287

Control rod drive hydraulic system  

DOEpatents

A hydraulic system for a control rod drive (CRD) includes a variable output-pressure CR pump operable in a charging mode for providing pressurized fluid at a charging pressure, and in a normal mode for providing the pressurized fluid at a purge pressure, less than the charging pressure. Charging and purge lines are disposed in parallel flow between the CRD pump and the CRD. A hydraulic control unit is disposed in flow communication in the charging line and includes a scram accumulator. An isolation valve is provided in the charging line between the CRD pump and the scram accumulator. A controller is operatively connected to the CRD pump and the isolation valve and is effective for opening the isolation valve and operating the CRD pump in a charging mode for charging the scram accumulator, and closing the isolation valve and operating the CRD pump in a normal mode for providing to the CRD through the purge line the pressurized fluid at a purge pressure lower than the charging pressure.

Ose, Richard A. (San Jose, CA)

1992-01-01

288

Evolution of cosmic string networks  

NASA Technical Reports Server (NTRS)

A discussion of the evolution and observable consequences of a network of cosmic strings is given. A simple model for the evolution of the string network is presented, and related to the statistical mechanics of string networks. The model predicts the long string density throughout the history of the universe from a single parameter, which researchers calculate in radiation era simulations. The statistical mechanics arguments indicate a particular thermal form for the spectrum of loops chopped off the network. Detailed numerical simulations of string networks in expanding backgrounds are performed to test the model. Consequences for large scale structure, the microwave and gravity wave backgrounds, nucleosynthesis and gravitational lensing are calculated.

Albrecht, Andreas; Turok, Neil

1989-01-01

289

Current balancing for battery strings  

DOEpatents

A battery plant is described which features magnetic circuit means for balancing the electrical current flow through a pluraliircuitbattery strings which are connected electrically in parallel. The magnetic circuit means is associated with the battery strings such that the conductors carrying the electrical current flow through each of the battery strings pass through the magnetic circuit means in directions which cause the electromagnetic fields of at least one predetermined pair of the conductors to oppose each other. In an alternative embodiment, a low voltage converter is associated with each of the battery strings for balancing the electrical current flow through the battery strings.

Galloway, James H. (New Baltimore, MI)

1985-01-01

290

Update on String Theory  

E-print Network

The first part of this report gives a very quick sketch of how string theory concepts originated and evolved during its first 25 years (1968-93). The second part presents a somewhat more detailed discussion of the highlights of the past decade. The final part discusses some of the major problems that remain to be solved.

John H. Schwarz

2003-04-28

291

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

292

Experimenting with Guitar Strings  

NASA Astrophysics Data System (ADS)

What follows is a description of a simple experiment developed in a nonmathematical general education science course on sound and light for fine arts students in which a guitar is used with data collection hardware and software to verify the properties of standing waves on a string.

LoPresto, Michael C.

2006-11-01

293

How and why cells grow as rods.  

PubMed

The rod is a ubiquitous shape adopted by walled cells from diverse organisms ranging from bacteria to fungi to plants. Although rod-like shapes are found in cells of vastly different sizes and are constructed by diverse mechanisms, the geometric similarities among these shapes across kingdoms suggest that there are common evolutionary advantages, which may result from simple physical principles in combination with chemical and physiological constraints. Here, we review mechanisms of constructing rod-shaped cells and the bases of different biophysical models of morphogenesis, comparing and contrasting model organisms in different kingdoms. We then speculate on possible advantages of the rod shape, and suggest strategies for elucidating the relative importance of each of these advantages. PMID:25185019

Chang, Fred; Huang, Kerwyn

2014-08-01

294

Impact of AD995 alumina rods  

NASA Astrophysics Data System (ADS)

Gas guns and velocity interferometric techniques have been used to determine the loading behavior of AD995 alumina rods 19 mm in diameter by 75 mm and 150 mm long, respectively. Graded-density materials were used to impact both bare and sleeved alumina rods while the velocity interferometer was used to monitor the axial-velocity of the free end of the rods. Results of these experiments demonstrate that (1) a time-dependent stress pulse generated during impact allows an efficient transition from the initial uniaxial strain loading to a uniaxial stress state as the stress pulse propagates through the rod, and (2) the intermediate loading rates obtained in this configuration lie between split Hopkinson bar and shock-loading techniques.

Chbabildas, L. C.; Furnish, M. D.; Reinhart, W. D.; Grady, D. E.

1998-07-01

295

Bouncing Balls and Hot Rod Races.  

ERIC Educational Resources Information Center

This paper presents the Bouncing Ball Experiment which models quadratic and exponential functions, and the Hot Rod Races activity that explores velocity and acceleration. Activities include directions for the use of TI-82 and TI-83 calculators. (YDS)

Tibbs, Peggy; Sherrill, Donna

296

Coiling of elastic rods on rigid substrates  

E-print Network

We investigate the deployment of a thin elastic rod onto a rigid substrate and study the resulting coiling patterns. In our approach, we combine precision model experiments, scaling analyses, and computer simulations towards ...

Khalid Jawed, Mohammad

2014-01-01

297

Mechanical behavior of elastic rods under constraint  

E-print Network

We present the results of an experimental investigation of the mechanics of thin elastic rods under a variety of loading conditions. Four scenarios are explored, with increasing complexity: i) the shape of a naturally ...

Miller, James Thomas, Ph. D. Massachusetts Institute of Technology

2014-01-01

298

Impact of AD995 alumina rods  

SciTech Connect

Gas guns and velocity interferometric techniques have been used to determine the loading behavior of an AD995 alumina rod 19 mm in diameter by 75 mm and 150 mm long, respectively. Graded-density materials were used to impact both bare and sleeved alumina rods while the velocity interferometer was used to monitor the axial-velocity of the free end of the rods. Results of these experiments demonstrate that (1) a time-dependent stress pulse generated during impact allows an efficient transition from the initial uniaxial strain loading to a uniaxial stress state as the stress pulse propagates through the rod, and (2) the intermediate loading rates obtained in this configuration lie between split Hopkinson bar and shock-loading techniques.

Chhabildas, L.C.; Furnish, M.D.; Reinhart, W.D. [Sandia National Labs., Albuquerque, NM (United States); Grady, D.E. [Applied Research Associates, Inc., Albuquerque, NM (United States)

1997-10-01

299

Alignment of Rods and Partition of Integers  

E-print Network

Alignment of Rods and Partition of Integers Eli Ben-Naim Los Alamos National Laboratory Poster possible for arbitrary averaging rates E. Ben-Naim and P.L. Krapivsky, Phys. Rev. E 73, 031109 (2006) #12;

Ben-Naim, Eli

300

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

301

Double-clad nuclear fuel safety rod  

DOEpatents

A device for shutting down a nuclear reactor during an undercooling or overpower event, whether or not the reactor's scram system operates properly. This is accomplished by double-clad fuel safety rods positioned at various locations throughout the reactor core, wherein melting of a secondary internal cladding of the rod allows the fuel column therein to shift from the reactor core to place the reactor in a subcritical condition.

McCarthy, William H. (Los Altos, CA); Atcheson, Donald B. (Cupertino, CA); Vaidyanathan, Swaminathan (San Jose, CA)

1984-01-01

302

Colloidal Interactions in Suspensions of Rods  

SciTech Connect

We report direct measurements of entropic interactions of colloidal spheres in suspensions of rodlike fd bacteriophage. We investigate the influence of sphere size, rod concentration, and ionic strength on these interactions. Although the results compare favorably with a recent calculation, small discrepancies reveal entropic effects due to rod flexibility. At high salt concentrations, the potential turns repulsive as a result of viral adsorption on the spheres and viral bridging between the spheres.

Lin, Keng-hui; Crocker, John C.; Zeri, Ana C.; Yodh, A. G.

2001-08-20

303

Measurements of control rod efficiency in RBMK critical assembly upon dropping of the rods  

NASA Astrophysics Data System (ADS)

The efficiency of control rods in the RBMK critical assembly was measured in the case where one manual-control rod (MCR) is dropped from a steady critical state, and several other MCRs were additionally dropped after 44 s. The measured number of neutrons in the assembly during and after dropping of the rods was used to calculate the efficiency values of the rods by solution of the system of point kinetics equations. A series of methods of the initial data treatment for determination of the desired values of reactivity without the calculated corrections were used.

Zhitarev, V. E.; Kachanov, V. M.; Sergevnin, A. Yu.; Lebedev, G. V.

2014-12-01

304

Contaminants of legacy and emerging concern in largescale suckers (Catostomus macrocheilus) and the foodweb in the lower Columbia River, Oregon and Washington, USA.  

PubMed

We investigated occurrence, transport pathways, and effects of polybrominated diphenyl ether (PBDE) flame retardants and other endocrine disrupting chemicals (EDCs) in aquatic media and the foodweb in the lower Columbia River. In 2009 and 2010, foodweb sampling at three sites along a gradient of contaminant exposure near Skamania (Washington), Columbia City (Oregon) and Longview (Washington) included water (via passive samplers), bed sediment, invertebrate biomass residing in sediment, a resident fish species (largescale suckers [Catostomus macrocheilus]), and eggs from osprey (Pandion haliaetus). This paper primarily reports fish tissue concentrations. In 2009, composites of fish brain, fillet, liver, stomach, and gonad tissues revealed that overall contaminant concentrations were highest in livers, followed by brain, stomach, gonad, and fillet. Concentrations of halogenated compounds in tissue samples from all three sites ranged from <1 to 400nanograms per gram of wet tissue. Several chemical classes, including PBDEs, organochlorine pesticides, and polychlorinated biphenyls (PCBs), were detected at all sites and in nearly all fish tissues sampled. In 2010, only fish livers were sampled and inter-site concentration differences were not as pronounced as in 2009. Chemical concentrations in sediments, fish tissues, and osprey eggs increased moving downstream from Skamania to the urbanized sites near Columbia City and Longview. Numerous organochlorine (OC) pesticides, both banned and currently used, and PBDEs, were present at each site in multiple media and concentrations exceeded environmental quality benchmarks in some cases. Frequently detected OC compounds included hexachlorobenzene, pentachloroanisole, dichlorodiphenyltrichloroethane (DDT) and its degradates, chlorpyrifos, and oxyfluorofen. Biomagnification of BDE47, 100, 153, and 154 occurred in largescale suckers and osprey eggs. Results support the hypothesis that contaminants in the environment lead to bioaccumulation and potential negative effects in multiple levels of the foodweb. PMID:24462179

Nilsen, Elena; Zaugg, Steven; Alvarez, David; Morace, Jennifer; Waite, Ian; Counihan, Timothy; Hardiman, Jill; Torres, Leticia; Patiño, Reynaldo; Mesa, Matthew; Grove, Robert

2014-06-15

305

Health status of Largescale Sucker (Catostomus macrocheilus) collected along an organic contaminant gradient in the lower Columbia River, Oregon and Washington, USA.  

PubMed

The health of Largescale Sucker (Catostomus macrocheilus) in the lower Columbia River (USA) was evaluated using morphometric and histopathological approaches, and its association with organic contaminants accumulated in liver was evaluated in males. Fish were sampled from three sites along a contaminant gradient. In 2009, body length and mass, condition factor, gonadosomatic index, and hematocrit were measured in males and females; liver and gonad tissue were collected from males for histological analyses; and organ composites were analyzed for contaminant content in males. In 2010, additional data were collected for males and females, including external fish condition assessment, histopathologies of spleen, kidney and gill and, for males, liver contaminant content. Multivariate analysis of variance indicated that biological traits in males, but not females, differed among sites in 2009 and 2010. Discriminant function analysis indicated that site-related differences among male populations were relatively small in 2009, but in 2010, when more variables were analyzed, males differed among sites in regards to kidney, spleen, and liver histopathologies and gill parasites. Kidney tubular hyperplasia, liver and spleen macrophage aggregations, and gill parasites were generally more severe in the downstream sites compared to the reference location. The contaminant content of male livers was also generally higher downstream, and the legacy pesticide hexachlorobenzene and flame retardants BDE-47 and BDE-154 were the primary drivers for site discrimination. However, bivariate correlations between biological variables and liver contaminants retained in the discriminant models failed to reveal associations between the two variable sets. In conclusion, whereas certain non-reproductive biological traits and liver contaminant contents of male Largescale Sucker differed according to an upstream-downstream gradient in the lower Columbia River, results from this study did not reveal the specific environmental factors responsible for the differences in health status among fish populations. PMID:24041613

Torres, Leticia; Nilsen, Elena; Grove, Robert; Patiño, Reynaldo

2014-06-15

306

International symposium on fuel rod simulators: development and application  

SciTech Connect

Separate abstracts are included for each of the papers presented concerning fuel rod simulator operation and performance; simulator design and evaluation; clad heated fuel rod simulators and fuel rod simulators for cladding investigations; fuel rod simulator components and inspection; and simulator analytical modeling. Ten papers have previously been input to the Energy Data Base.

McCulloch, R.W. (comp.)

1981-05-01

307

Correspondence principle for black holes and strings  

Microsoft Academic Search

For most black holes in string theory, the Schwarzschild radius in string units decreases as the string coupling is reduced. We formulate a correspondence principle, which states that (i) when the size of the horizon drops below the size of a string, the typical black hole state becomes a typical state of strings and D-branes with the same charges, and

Gary T. Horowitz; Joseph Polchinski

1997-01-01

308

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

309

Axions in String Theory  

SciTech Connect

In the context of string theory, axions appear to provide the most plausible solution of the strong CP problem. However, as has been known for a long time, in many string-based models, the axion coupling parameter Fa is several orders of magnitude higher than the standard cosmological bounds. We re-examine this problem in a variety of models, showing that Fa is close to the GUT scale or above in many models that have GUT-like phenomenology, as well as some that do not. On the other hand, in some models with Standard Model gauge fields supported on vanishing cycles, it is possible for Fa to be well below the GUT scale.

Svrcek, Peter; /Stanford U., Phys. Dept. /SLAC; Witten, Edward; /Princeton, Inst. Advanced Study

2006-06-09

310

Higher spins & strings  

NASA Astrophysics Data System (ADS)

It is natural to believe that the free symmetric product orbifold CFT is dual to the tensionless limit of string theory on AdS3 × S3 × . At this point in moduli space, string theory is expected to contain a Vasiliev higher spin theory as a subsector. We confirm this picture explicitly by showing that the large level limit of the =4 cosets of arXiv:1305.4181, that are dual to a higher spin theory on AdS3, indeed describe a closed subsector of the symmetric product orbifold. Furthermore, we reorganise the full partition function of the symmetric product orbifold in terms of representations of the higher spin algebra (or rather its extension). In particular, the unbroken stringy symmetries of the tensionless limit are captured by a large chiral algebra which we can describe explicitly in terms of an infinite sum of representations, thereby exhibiting a vast extension of the conventional higher spin symmetry.

Gaberdiel, Matthias R.; Gopakumar, Rajesh

2014-11-01

311

Strings and vortex rings  

E-print Network

We treat string propagation and interaction in the presence of a background Neveu-Schwarz three-form field strength, suitable for describing vortex rings in a superfluid or low-viscosity normal fluid. A circular vortex ring exhibits instabilities which have been recognized for many years, but whose precise boundaries we determine for the first time analytically in the small core limit. Two circular vortices colliding head-on exhibit stronger instabilities which cause splitting into many small vortices at late times. We provide an approximate analytic treatment of these instabilities and show that the most unstable wavelength is parametrically larger than a dynamically generated length scale which in many hydrodynamic systems is close to the cutoff. We also summarize how the string construction we discuss can be derived from the Gross-Pitaevskii lagrangian, and also how it compares to the action for giant gravitons.

Steven S. Gubser; Revant Nayar; Sarthak Parikh

2014-08-10

312

Strings and vortex rings  

E-print Network

We treat string propagation and interaction in the presence of a background Neveu-Schwarz three-form field strength, suitable for describing vortex rings in a superfluid or low-viscosity normal fluid. A circular vortex ring exhibits instabilities which have been recognized for many years, but whose precise boundaries we determine for the first time analytically in the small core limit. Two circular vortices colliding head-on exhibit stronger instabilities which cause splitting into many small vortices at late times. We provide an approximate analytic treatment of these instabilities and show that the most unstable wavelength is parametrically larger than a dynamically generated length scale which in many hydrodynamic systems is close to the cutoff. We also summarize how the string construction we discuss can be derived from the Gross-Pitaevskii lagrangian, and also how it compares to the action for giant gravitons.

Gubser, Steven S; Parikh, Sarthak

2014-01-01

313

Coulomb string tension, asymptotic string tension, and the gluon chain  

We compute, via numerical simulations, the non-perturbative Coulomb potential and position-space ghost propagator in pure SU(3) gauge theory in Coulomb gauge. We find that that the Coulomb potential scales nicely in accordance with asymptotic freedom, that the Coulomb potential is linear in the infrared, and that the Coulomb string tension is about four times larger than the asymptotic string tension. We explain how it is possible that the asymptotic string tension can be lower than the Coulomb string tension by a factor of four.

Greensite, Jeff; Szczepaniak, Adam P.

2015-02-01

314

Transposition invariant string matching  

Microsoft Academic Search

Given strings A = a1a2 ...a m and B = b1b2 ...b n over an alphabet ? ? U ,w hereU is some numerical universe closed under addition and subtraction, and a distance function d(A,B) that gives the score of the best (partial) matching of A and B ,t hetransposition invariant distance is mint?U{d(A + t,B) } ,w hereA +

Veli Mäkinen; Gonzalo Navarro; Esko Ukkonen

2005-01-01

315

Supersymmetric String Solitons  

Microsoft Academic Search

These notes are based on lectures given by C. Callan and J. Harvey at the\\u000a1991 Trieste Spring School on String Theory and Quantum Gravity. The subject is\\u000athe construction of supersymmetric soliton solutions to superstring theory. A\\u000abrief review of solitons and instantons in supersymmetric theories is\\u000apresented. Yang-Mills instantons are then used to construct soliton solutions\\u000ato heterotic

Curtis G. Callan; Jeffrey A. Harvey; Andrew Strominger

1991-01-01

316

Schreibender Quelltextanalyse String  

E-print Network

15 Das Package java.net 15.6 Schreibender Zugriff auf eine URL 15­14 6 Quelltextanalyse String Applets laden 15­15 5 15.7 Internetseiten via Applets laden 15.7.1 in URLButton ­ URLButton n Button t URL t URLButton URLButton t n Button 1 11 t URL u 1 1 u URLButton t n u u URL u 1 15 u u u 1 t u u 1 1 1 u URL tURL

Arndt, Holger

317

String bowing revisited  

NASA Astrophysics Data System (ADS)

This work explores an integral equation formulation of a generalised bowing problem incorporating air resistance and bow width. The Keller/Friedlander results are obtained as a special case. Some illustrative results are presented for a lightly damped string bowed at a point. The related integral equations are solved using Filon's method, a clever but relatively unknown algorithm for the numerical evaluation of integrals with rapidly oscillating trignometric kernels.

Lindsay, K. A.

1995-11-01

318

Isolation and Characterization of Cytoplasmic Cofilin-Actin Rods*  

PubMed Central

Cofilin-actin bundles (rods), which form in axons and dendrites of stressed neurons, lead to synaptic dysfunction and may mediate cognitive deficits in dementias. Rods form abundantly in the cytoplasm of non-neuronal cells in response to many treatments that induce rods in neurons. Rods in cell lysates are not stable in detergents or with added calcium. Rods induced by ATP-depletion and released from cells by mechanical lysis were first isolated from two cell lines expressing chimeric actin-depolymerizing factor (ADF)/cofilin fluorescent proteins by differential and equilibrium sedimentation on OptiPrep gradients and then from neuronal and non-neuronal cells expressing only endogenous proteins. Rods contain ADF/cofilin and actin in a 1:1 ratio. Isolated rods are stable in dithiothreitol, EGTA, Ca2+, and ATP. Cofilin-GFP-containing rods are stable in 500 mm NaCl, whereas rods formed from endogenous proteins are significantly less stable in high salt. Proteomic analysis of rods formed from endogenous proteins identified other potential components whose presence in rods was examined by immunofluorescence staining of cells. Only actin and ADF/cofilin are in rods during all phases of their formation; furthermore, the rapid assembly of rods in vitro from these purified proteins at physiological concentration shows that they are the only proteins necessary for rod formation. Cytoplasmic rod formation is inhibited by cytochalasin D and jasplakinolide. Time lapse imaging of rod formation shows abundant small needle-shaped rods that coalesce over time. Rod filament lengths measured by ultrastructural tomography ranged from 22 to 1480 nm. These results suggest rods form by assembly of cofilin-actin subunits, followed by self-association of ADF/cofilin-saturated F-actin. PMID:20022956

Minamide, Laurie S.; Maiti, Sankar; Boyle, Judith A.; Davis, Richard C.; Coppinger, Judith A.; Bao, Yunhe; Huang, Timothy Y.; Yates, John; Bokoch, Gary M.; Bamburg, James R.

2010-01-01

319

Fuel rod mechanical deformation during the PBF/LOFT lead rod loss-of-coolant experiments  

SciTech Connect

Results of four PBF/LOFT Lead Rod (LLR) sequential blowdown tests conducted in the Power Burst Facility (PBF) are presented. Each test employed four separately shrouded fuel rods. The primary objective of the test series was to evaluate the extent of mechanical deformation that would be expected to occur to low pressure (0.1 MPa), light water reactor design fuel rods when subjected to a series of double ended cold leg break loss-of-coolant accident (LOCA) tests, and to determine whether subjecting these deformed fuel rods to subsequent testing would result in rod failure. The extent of mechanical deformation (buckling, collapse, or waisting of the cladding) was evaluated by comparison of cladding temperature and system pressure measurements with out-of-pile experimental data, and by posttest visual examinations and cladding diametral measurements.

Varacalle, D.J. Jr.; MacDonald, P.E.; Shiozawa, S.; Driskell, W.E.

1980-01-01

320

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

321

Comparing double string theory actions  

NASA Astrophysics Data System (ADS)

Aimed to a deeper comprehension of a manifestly T-dual invariant formulation of string theory, in this paper a detailed comparison between the non-covariant action proposed by Tseytlin and the covariant one proposed by Hull is done. These are obtained by making both the string coordinates and their duals explicitly appear, on the same footing, in the world-sheet action, so "doubling" the string coordinates along the compact dimensions. After a discussion on the nature of the constraints in both the models and the relative quantization, it results that the string coordinates and their duals behave like "non-commuting" phase space coordinates but their expressions in terms of Fourier modes generate the oscillator algebra of the standard bosonic string. A proof of the equivalence of the two formulations is given. Furthermore, open-string solutions are also discussed.

De Angelis, L.; Gionti S. J, G.; Marotta, R.; Pezzella, F.

2014-04-01

322

Radiological characterization of spent control rod assemblies  

SciTech Connect

This document represents the final report of an ongoing study to provide radiological characterizations, classifications, and assessments in support of the decommissioning of nuclear power stations. This report describes the results of non-destructive and laboratory radionuclide measurements, as well as waste classification assessments, of BWR and PWR spent control rod assemblies. The radionuclide inventories of these spent control rods were determined by three separate methodologies, including (1) direct assay techniques, (2) calculational techniques, and (3) by sampling and laboratory radiochemical analyses. For the BWR control rod blade (CRB) and PWR burnable poison rod assembly (BPRA), {sup 60}Co and {sup 63}Ni, present in the stainless steel cladding, were the most abundant neutron activation products. The most abundant radionuclide in the PWR rod cluster control assembly (RCCA) was {sup 108m}Ag (130 yr halflife) produced in the Ag-In-Cd alloy used as the neutron poison. This radionuclide will be the dominant contributor to the gamma dose rate for many hundreds of years. The results of the direct assay methods agree very well ({+-}10%) with the sampling/radiochemical measurements. The results of the calculational methods agreed fairly well with the empirical measurements for the BPRA, but often varied by a factor of 5 to 10 for the CRB and the RCCA assemblies. If concentration averaging and encapsulation, as allowed by 10CFR61.55, is performed, then each of the entire control assemblies would be classified as Class C low-level radioactive waste.

Lepel, E.A.; Robertson, D.E.; Thomas, C.W.; Pratt, S.L.; Haggard, D.L. [Pacific Northwest Lab., Richland, WA (United States)

1995-10-01

323

String percolation and the Glasma  

NASA Astrophysics Data System (ADS)

We compare string percolation phenomenology to Glasma results on particle rapidity densities, effective string or flux tube intrinsic correlations, the ridge phenomena and long range forward-backward correlations. Effective strings may be a tool to extend the Glasma to the low density QCD regime. A good example is given by the minimum of the negative binomial distribution parameter k expected to occur at low energy/centrality.

de Deus, J. Dias; Pajares, C.

2011-01-01

324

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

325

Rod consolidation at the West Valley Demonstration Project  

SciTech Connect

A rod consolidation demonstration with irradiated pressurized water reactor fuel was recently conducted by personnel from Nuclear Assurance Corporation and West Valley Nuclear Services Company at the West Valley Demonstration Project in West Valley, New York. The rod consolidation demonstration involved pulling all of the fuel rods from six fuel Assemblies. In general, the rod pulling proceeded smoothly. The highest compaction ratio attained was 1:8:1. Among the total of 1074 fuel rods were some known degraded rods (they had collapsed cladding, a result of in-reactor fuel densification), but no rods were broken or dropped during the demonstration. One aim was to gather information on the effect of rod consolidation operations on the integrity of the fuel rods during subsequent handling and storage. Another goal was to collect information on the condition and handling of intact, damaged, and failed fuel that has been in storage for an extended period. 9 refs., 8 figs., 1 tab.

Bailey, W.J.

1986-12-01

326

Numerical experiments on string cosmology  

NASA Astrophysics Data System (ADS)

We investigate some classical aspects of fundamental strings via numerical experiments. In particular, we study the thermodynamics of a string network within a toroidal universe, as a function of string energy density and space dimensionality. We find that when the energy density of the system is low, the dominant part of the string is in the form of closed loops of the shortest allowed size, which correspond to the momentum string modes. At a certain critical energy density corresponding to the Hagedorn temperature, the system undergoes a phase transition characterized by the formation of very long loops, winding a number of times around the torus. These loops correspond to the winding string modes. As the energy density is increased, all the extra energy goes into these long strings. We then study the lifetime of winding modes as a function of the space densionality. We find that in the low--energy density regime, long winding strings decay only if the space dimensionality of the toroidal universe is equal to 3. This finding supports the proposed cosmological scenario by Brandenberger and Vafa, which attempts to explain the space dimensionality and to avoid the initial singularity by means of string theory.

Sakellariadou, Mairi

1996-02-01

327

Cosmic Sparks from Superconducting Strings  

SciTech Connect

We investigate cosmic sparks from cusps on superconducting cosmic strings in light of the recently discovered millisecond radio burst by Lorimer et al.. We find that the observed duration, fluence, spectrum, and event rate can be reasonably explained by grand unification scale superconducting cosmic strings that carry currents {approx}10{sup 5} GeV. The superconducting string model predicts an event rate that falls off only as S{sup -1/2}, where S is the energy flux, and hence predicts a population of very bright bursts. Other surveys, with different observational parameters, are shown to impose tight constraints on the superconducting string model.

Vachaspati, Tanmay [Institute for Advanced Study, Princeton, New Jersey 08540 (United States); CERCA, Physics Department, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106-7079 (United States)

2008-10-03

328

Cosmic strings and Natural Inflation  

E-print Network

In the present work we discuss cosmic strings in natural inflation. Our analysis is based entirely on the CMB quadrupole temperature anisotropy and on the existing upper bound on the cosmic string tension. Our results show that the allowed range for both parameters of the inflationary model is very different from the range obtained recently if cosmic strings are formed at the same time with inflation, while if strings are formed after inflation we find that the parameters of the inflationary model are similar to the ones obtained recently.

Grigoris Panotopoulos

2007-06-19

329

Generating Necklaces and Strings with Forbidden Substrings  

E-print Network

are known as Fibonacci strings, since they are counted by the Fibonacci numbers. The set of circular binary strings that avoid 11 are counted by the Lucas numbers. Within combinatorics, the counting of strings

Ruskey, Frank

330

The role of glutathione S-transferases in the hepatic metabolism of benzo[a]pyrene in white suckers (Catostomus commersoni) from polluted and reference sites in the Great Lakes.  

PubMed

1. Orally administered 3H-benzo[a]pyrene (3H-BaP) was excreted in the bile of White Suckers predominantly as water soluble metabolites some of which were hydrolyzed by arylsulfatase or beta-glucuronidase. 2. Non-hydrolysible polar metabolites comprised a substantial proportion of biliary metabolites. 3. HPLC analysis revealed fluorescent and 3H-labelled peaks which co-eluted with standards of the glucuronide and sulfate conjugates of BaP. 4. The most polar peak co-chromatographed with a double-radiolabelled metabolite produced in vitro with 3H-BaP and 35S-glutathione. 5. Inhibition of epoxide hydrolase in vitro reduced all water soluble metabolites except the glutathione conjugate of BaP. 6. Glutathione conjugation represents a major hepatic detoxication pathway of BaP in White Suckers. PMID:1971553

Kirby, G M; Bend, J R; Smith, I R; Hayes, M A

1990-01-01

331

Corticotropin-releasing factor (CRF) gene family in the brain of the teleost fish Catostomus commersoni (white sucker): molecular analysis predicts distinct precursors for two CRFs and one urotensin I peptide.  

PubMed

Molecular cloning experiments indicate the presence of two distinct CRF genes in the sucker genome encoding independent 162-amino-acid precursors, which both consist of a signal sequence, succeeded by a cryptic peptide and subsequently by the hormone moiety. The two 41-amino-acid CRF peptides differ by an Ala-->Val substitution at amino acid position 28. CRF transcripts are primarily found in the sucker pre-optic nucleus (PON), to a much lesser extent in the lateral tuberal nucleus (LTN). In contrast, urotensin I (U I) encoding mRNA is equally present in both tissues. In urophysectomized fish, U I mRNA is elevated especially in LTN tissue, while CRF mRNA levels remain more or less constant in the PON and LTN regions. PMID:1726976

Morley, S D; Schönrock, C; Richter, D; Okawara, Y; Lederis, K

1991-09-01

332

Power requirement of rotating rods in airflow  

NASA Technical Reports Server (NTRS)

Experiments were performed to determine the power required for rotating a rotor disc fitted with a number of radially arranged rods placed into a ducted airflow. An array of stationary rods, also radially arranged, were placed upstream close to the rotor with a small gap between the rods to cause wake interference. The results show that power increased with increasing airflow and the rate of increase varied considerably. At lower values of airflow the rate of increase was larger than at higher airflow and definite power peaks occurred at certain airflow rates, where the power attained a maximum within the test airflow range. During the test a maximum blade passage frequency of 2037 Hz was attained.

Barna, P. S.; Crossman, G. R.

1974-01-01

333

Magnetic switch for reactor control rod. [LMFBR  

DOEpatents

A magnetic reed switch assembly is described for activating an electromagnetic grapple utilized to hold a control rod in position above a reactor core. In normal operation the magnetic field of a permanent magnet is short-circuited by a magnetic shunt, diverting the magnetic field away from the reed switch. The magnetic shunt is made of a material having a Curie-point at the desired release temperature. Above that temperature the material loses its ferromagnetic properties, and the magnetic path is diverted to the reed switch which closes and short-circuits the control circuit for the control rod electro-magnetic grapple which allows the control rod to drop into the reactor core for controlling the reactivity of the core.

Germer, J.H.

1982-09-30

334

Torque requirement of rotating rods in airflow  

NASA Technical Reports Server (NTRS)

Experiments were performed to determine the torque required for rotating a rotor disk fitted with a number of radially arranged rods placed into a ducted airflow. An array of stationary rods, also radially arranged, was placed upstream close to the rotor with a small gap between the rods to cause wake interference. The results show that torque generally increased with airflow and the rate of increase varied considerably. At lower values of airflow, the rate of increase was larger than at higher airflow, and definite torque peaks occurred at certain airflow rates, where the torque attained a maximum within the test airflow range. During the test, a maximum blade passage frequency of 2037 Hz was attained. The results also show that the torque peaks occurred at the same Strouhal number for all speeds.

Barna, P. S.; Crossman, G. R.

1979-01-01

335

Hydrodynamics of self-propelled hard rods  

E-print Network

Motivated by recent simulations and by experiments on aggregation of gliding bacteria, we study a model of the collective dynamics of self-propelled hard rods on a substrate in two dimensions. The rods have finite size, interact via excluded volume and their dynamics is overdamped by the interaction with the substrate. Starting from a microscopic model with non-thermal noise sources, a continuum description of the system is derived. The hydrodynamic equations are then used to characterize the possible steady states of the systems and their stability as a function of the particles packing fraction and the speed of self propulsion.

Aparna Baskaran; M. Cristina Marchetti

2007-08-17

336

Method for producing titanium aluminide weld rod  

DOEpatents

A process for producing titanium aluminide weld rod comprising: attaching one end of a metal tube to a vacuum line; placing a means between said vacuum line and a junction of the metal tube to prevent powder from entering the vacuum line; inducing a vacuum within the tube; placing a mixture of titanium and aluminum powder in the tube and employing means to impact the powder in the tube to a filled tube; heating the tube in the vacuum at a temperature sufficient to initiate a high-temperature synthesis (SHS) reaction between the titanium and aluminum; and lowering the temperature to ambient temperature to obtain a intermetallic titanium aluminide alloy weld rod.

Hansen, Jeffrey S. (Corvallis, OR); Turner, Paul C. (Albany, OR); Argetsinger, Edward R. (Albany, OR)

1995-01-01

337

Nuclear reactor fuel rod attachment system  

DOEpatents

A reusable system is described for removably attaching a nuclear reactor fuel rod to a support member. A locking cap is secured to the fuel rod and a locking strip is fastened to the support member. The locking cap has two opposing fingers shaped to form a socket having a body portion. The locking strip has an extension shaped to rigidly attach to the socket's body portion. The locking cap's fingers are resiliently deflectable. For attachment, the locking cap is longitudinally pushed onto the locking strip causing the extension to temporarily deflect open the fingers to engage the socket's body portion. For removal, the process is reversed.

Not Available

1980-09-17

338

Alignment of rods and partition of integers  

NASA Astrophysics Data System (ADS)

We study dynamical ordering of rods. In this process, rod alignment via pairwise interactions competes with diffusive wiggling. Under strong diffusion, the system is disordered, but at weak diffusion, the system is ordered. We present an exact steady-state solution for the nonlinear and nonlocal kinetic theory of this process. We find the Fourier transform as a function of the order parameter, and show that Fourier modes decay exponentially with the wave number. We also obtain the order parameter in terms of the diffusion constant. This solution is obtained using iterated partitions of the integer numbers.

Ben-Naim, E.; Krapivsky, P. L.

2006-03-01

339

Pattern selection dynamics in rod eutectics  

NASA Astrophysics Data System (ADS)

The cooperative or diffusively coupled growth of multiple phases during solidification is one of the most widely observed and generally important classes of phase transformations in materials. Technologically, low melting temperature and small freezing range contribute to excellent casting fluidity and fine composite structures give rise to favorable properties. Both of these features contribute to the wide application of eutectic alloys in the casting, welding, and soldering of engineered components. Despite the broad-based technological importance, many fundamental questions regarding eutectic solidification remain unanswered, severely limiting our ability to employ computational methods in the prediction of microstructure for the effective design of new materials and processes. At the core of the most persistent questions, lie problems involving multicomponent thermodynamics, solid-liquid and solid-solid interfacial phenomena, morphological stability, chemical and thermal diffusion, and nucleation phenomena. In the current study, pattern selection dynamics in rod eutectics are investigated using systematic directional solidification experiments and phase field simulations. Directional solidification of a succinonitrile-camphor (SCN-DC) transparent alloy in thin slab geometries of various thicknesses reveals two main points. First, a velocity is indentified at which a transition in array basis vectors is observed in specimens with many rows of rods (i.e. bulk). This transition amounts to a 90 degree rotation of the rod array, shifting from alignment of 1st nearest neighbors to alignment of 2nd nearest neighbors along the slide wall. Second, significant array distortion is observed with decreasing slide thickness, delta, which ultimately leads to a single-row (quasi-3D) morphology where delta/lambda is on the order of unity. In our analysis of these observations, we use a geometrical model to describe the rod arrangement as a function of slide thickness, providing excellent agreement with observation, down to this quasi-3D regime. Further experimental investigation of the early stages of growth shows that the mechanisms involved in the initial dynamics are critical to the array development, especially under geometrical constraint. Phase field simulations show that several rod-type eutectic morphologies are stable over different growth/boundary conditions. Normal circular-rod staggered-array morphologies become unstable and give way to distorted rods and lamellar structures with decreasing material thickness. Distended or peanut-shaped rods are also observed under certain conditions. The boundaries of stability for these growth morphologies and the associated dynamics are investigated here.

Serefoglu, Melis

340

Intraoperative pulmonary embolism of Harrington rod during spinal surgery: the potential dangers of rod cutting.  

PubMed

This is a case report and laboratory-based biomechanics study. The objective is to report the first case of Titanium rod embolisation during scoliosis surgery into the Pulmonary artery. To investigate the potential of an unconstrained cut Titanium rod fragment to cause wounding with reference to recognised weapons. Embolisation of a foreign body to the heart is rare. Bullet embolisation to the heart and lungs is infrequently reported in the last 80 years. Iatrogenic cases of foreign body embolisation are very rare. Fifty 1-2 cm segments of Titanium rod were cut in an unconstrained manner and a novel method was used to calculate velocity. A high-speed camera (6,000 frames/s) was used to further measure velocity and study projectile motion. The wounding potential was investigated using lambs liver, high-speed photography and local dissection. Rod velocities were measured in excess of 23 m s(-1). Rods were seen to tumble end-over-end with a maximum speed of 560 revolutions/s. The maximum kinetic energy was 0.61 J which is approximately 2% that of a crossbow. This is sufficient to cause significant liver damage. The degree of surface damage and internal disruption was influenced by the orientation of the rod fragment at impact. An unconstrained cut segment of a Titanium rod has a significant potential to wound. Precautions should be taken to avoid this potentially disastrous but preventable complication. PMID:16804675

Aylott, Caspar E W; Hassan, Kamran; McNally, Donal; Webb, John K

2006-12-01

341

QED and String Theory  

E-print Network

We analyze the D9-D9bar system in type IIB string theory using Dp-brane probes. It is shown that the world-volume theory of the probe Dp-brane contains two-dimensional and four-dimensional QED in the cases with p=1 and p=3, respectively, and some applications of the realization of these well-studied quantum field theories are discussed. In particular, the two-dimensional QED (the Schwinger model) is known to be a solvable theory and we can apply the powerful field theoretical techniques, such as bosonization, to study the D-brane dynamics. The tachyon field created by the D9-D9bar strings appears as the fermion mass term in the Schwinger model and the tachyon condensation is analyzed by using the bosonized description. In the T-dualized picture, we obtain the potential between a D0-brane and a D8-D8bar pair using the Schwinger model and we observe that it consists of the energy carried by fundamental strings created by the Hanany-Witten effect and the vacuum energy due to a cylinder diagram. The D0-brane is treated quantum mechanically as a particle trapped in the potential, which turns out to be a system of a harmonic oscillator. As another application, we obtain a matrix theory description of QED using Taylor's T-duality prescription, which is actually applicable to a wide variety of field theories including the realistic QCD. We show that the lattice gauge theory is naturally obtained by regularizing the matrix size to be finite.

Shigeki Sugimoto; Kazuyoshi Takahashi

2004-03-24

342

Drill string gas data  

SciTech Connect

Data and supporting documentation were compiled and analyzed for 26 cases of gas grab samples taken during waste-tank core sampling activities between September 1, 1995 and December 31, 1997. These cases were tested against specific criteria to reduce uncertainties associated with in-tank sampling location and conditions. Of the 26 possible cases, 16 qualified as drill-string grab samples most likely to represent recently released waste gases. The data from these 16 ``confirmed`` cases were adjusted to remove non-waste gas contributions from core-sampling activities (argon or nitrogen purge), the atmospheric background, and laboratory sampler preparation (helium). The procedure for subtracting atmospheric, laboratory, and argon purge gases was unambiguous. No reliable method for determining the exact amount of nitrogen purge gas was established. Thus, the final set of ``Adjusted`` drill string gas data for the 6 nitrogen-purged cases had a greater degree of uncertainty than the final results for the 10 argon-purged cases. Including the appropriate amounts of uncertainty, this final set of data was added to the set of high-quality results from the Retained Gas Sampler (RGS), and good agreement was found for the N{sub 2}, H{sub 2}, and N{sub 2}O mole fractions sampled from common tanks. These results indicate that under favorable sampling conditions, Drill-String (DS) grab samples can provide reasonably accurate information about the dominant species of released gas. One conclusion from this set of total gas data is that the distribution of the H{sub 2} mole fractions is bimodal in shape, with an upper bound of 78%.

Siciliano, E.R.

1998-05-12

343

Twist Field as Three String Interaction Vertex in Light Cone String Field Theory  

E-print Network

It has been suggested that matrix string theory and light-cone string field theory are closely related. In this paper, we investigate the relation between the twist field, which represents string interactions in matrix string theory, and the three-string interaction vertex in light-cone string field theory carefully. We find that the three-string interaction vertex can reproduce some of the most important OPEs satisfied by the twist field.

Isao Kishimoto; Sanefumi Moriyama; Shunsuke Teraguchi

2007-03-22

344

Sequestering in String Theory  

SciTech Connect

We study sequestering, a prerequisite for flavor-blind supersymmetry breaking in several high-scale mediation mechanisms, in compactifications of type IIB string theory. We find that although sequestering is typically absent in unwarped backgrounds, strongly warped compactifications do readily sequester. The AdS/CFT dual description in terms of conformal sequestering plays an important role in our analysis, and we establish how sequestering works both on the gravity side and on the gauge theory side. We pay special attention to subtle compactification effects that can disrupt sequestering. Our result is a step toward realizing an appealing pattern of soft terms in a KKLT compactification.

Kachru, Shamit; McAllister, Liam; Sundrum, Raman

2007-04-04

345

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

346

Singularities of Generalized Strings  

Microsoft Academic Search

We investigate the structure of a maximal chain of matrix functions whose Weyl coefficient belongs to \\u000a\\u000a\\u000a\\u000a\\u000a\\u000a\\u000a_boxclose ^ + \\u000a\\\\mathcal{N}_\\\\kappa ^ + \\u000a\\u000a. It is shown that its singularities must be of a very particular type. As an application we obtain detailed results on the structure of the singularities of a generalized string which are explicitly stated in terms of

Michael Kaltenbäck; Henrik Winkler; Harald Woracek

347

STRING THEORY Problem Set # 5  

E-print Network

STRING THEORY Problem Set # 5 oriented str* *ing theory, in flat space-time, in the critical dimension D = 26, and to tree level. a be ignored, use the results of a) to derive a relation between Newto* *n's constant of gravity, the string

348

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

349

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

350

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

351

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

352

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

353

A Platonic Sextet for Strings  

ERIC Educational Resources Information Center

The use of traditional string figures by the Dr. Schaffer and Mr. Stern Dance Ensemble led to experimentation with polyhedral string constructions. This article presents a series of polyhedra made with six loops of three colors which sequence through all the Platonic Solids.

Schaffer, Karl

2012-01-01

354

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.

355

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

356

Threading plasmonic nanoparticle strings with light  

PubMed Central

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. PMID:25065385

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

2014-01-01

357

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

358

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

359

String fields and their interactions  

NASA Astrophysics Data System (ADS)

In this thesis is devoted to illuminating the underlying structure of Witten's star product, which defines the interactions of open strings in cubic bosonic string field theory [3]. We give an in depth analysis of the product from the perspective of noncommutative geometry, specifically using the split string [19] and Moyal formalisms [20, 22]. We identify some fundamental algebraic features of the star product originating from the singular structure of the overlap conditions at the string midpoint. Finally, we use some of these insights to construct a consistent and nonsingular initial value formulation of the theory in lightcone time. Such a general formalism seems prerequisite to address questions of time, causality, and cosmology in string theory.

Erler, Theodore George, IV

2005-07-01

360

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

361

Testing strings at the LHC  

NASA Astrophysics Data System (ADS)

I discuss the main motivations and directions for physics beyond the Standard Model of elementary particles and I give a short introduction on string theory. This theory introduces a new physical constant, the string length, under which a new fundamental structure appears, changing drastically the laws of nature. In particular, lowering the string scale in the Te V region provides a theoretical framework for solving the so-called mass hierarchy problem: the apparent weakness of gravity can be accounted by the existence of large internal dimensions, in the submillimeter region, and transverse to a braneworld where our observed universe is confined. In these lectures, I describe the main properties of string phenomenology with high or low string scale. In the latter case, I discuss also its implications for new gravitational phenomena that can be observed at both particle colliders, and in non-accelerator experiments searching for new short range forces.

Antoniadis, I.

2013-07-01

362

The second string (phenomenology) revolution  

E-print Network

In the past three years our views on how the standard model of particle physics could be embedded into string theory have dramatically changed. The heterotic string is no longer the only possibility for such an embedding and other perturbative (or non-perturbative) corners of M-theory, like Type I or Type II strings seem now possible. It has also been realized that the string scale $M_s$ is not necessary close to the Planck scale and could be much smaller, of order the intermediate scale $\\sqrt{M_WM_p}$ or even close to the weak scale. In addition, semi-realistic three generation models have recently been constructed starting with Type IIB compact orientifolds. I briefly discuss some of these developements which represent a revolution in our understanding of string phenomenology.

L. E. Ibanez

1999-11-26

363

Textile composite rods operating in torsion  

Microsoft Academic Search

The load-carrying capacity of thick-walled composite rods loaded in torsion may be effectively controlled through variation of the winding scheme and structural and technological parameters of winding within the framework of the textile technology. Increase of the monolayer shear strength is attained by means of proper selection of the optimum reinforcement angle and degree of fibre weave during winding. This

Yu. M. Tarnopol'skii; V. L. Kulakov; A. M. Zakrzhevskii; D. D. Mungalov

1996-01-01

364

Impact of AD995 Alumina Rods  

NASA Astrophysics Data System (ADS)

Gas gun experiments combined with velocity interferometric techniques have been used to determine the loading behavior of an AD995 alumina rod 19mm in diameter by 75mm and 150mm long, respectively. Graded-density materials were used to impact both bare and sleeved alumina rods, while the velocity interferometer was used to monitor the axial-velocity of the free end of the rods. Results of these experiments, and CTH calculations will demonstrate two unique features of this novel test methodology: a time-dependent stress pulse generated during impact allows a smooth and efficient transition from the initial uniaxial strain loading to a uniaxial stress state as the stress pulse propagates through the rod, and (2) the intermediate loading rates obtained in this configuration lie between split hopkinson bar and shock-loading techniques and are not achieved easily by either of these techniques. The experiments are expected to simulate the development of a multi-dimensional constitutive model needed to simulate dynamic impact events.

Chhabildas, L. C.; Furnish, M. D.; Reinhart, W. D.; Grady, D. E.

1997-07-01

365

On the temperature of the moving rod  

E-print Network

In this paper the Lorentz transformation for temperature is derived and discussed. Considering the hyperbolic heat transport equation it is shown that T(prim) = gamma T, where gamma is the Lorentz factor, T denotes the temperature in the rest system and T(prim) is the temperature in the moving system (rod).

M. Kozlowski; J. Marciak-Kozlowska; M. Pelc

2007-08-30

366

Processing depleted uranium quad alloy penetrator rods  

Microsoft Academic Search

Two depleted uranium (DU) quad alloys were cast, extruded and rolled to produce penetrator rods. The two alloy combinations were (1) 1 wt % molybdenum (Mo), 1 wt % niobium (Nb), and 0.75 wt % titanium (Ti); and (2) 1 wt % tantalum (Ta), 1 wt % Nb, and 0.75 wt % Ti. This report covers the processing and results

Bokan

1987-01-01

367

Reorientation kinetics of superparamagnetic nanostructured rods  

E-print Network

The attractive interactions between oppositely charged species (colloids, macromolecules etc) dispersed in water are strong, and the direct mixing of solutions containing such species generally yields to a precipitation, or to a phase separation. We have recently developed means to control the electrostatically-driven attractions between nanoparticles and polymers in water, and at the same time to preserve the stability of the dispersions. We give here an account of the formation of supracolloidal aggregates obtained by co-assembly of 7 nm particles with copolymers. Nanostructured rods of length comprised between 5 and 50 microns and diameter 500 nm were investigated. By application of a magnetic field, the rods were found to reorient along with the magnetic field lines. The kinetics of reorientation was investigated using step changes of the magnetic field of amplitude 90 degrees. From the various results obtained, among which an exponential decay of the tangent of the angle made between the rod and the field, we concluded that the rods are superparamagnetic.

J. Fresnais; J. -F. Berret; B. Frka-Petesic; O. Sandre; R. Perzynski

2008-09-24

368

Drop Ejection From an Oscillating Rod  

NASA Technical Reports Server (NTRS)

The dynamics of a drop of a Newtonian liquid that is pendant from or sessile on a solid rod that is forced to undergo time-periodic oscillations along its axis is studied theoretically. The free boundary problem governing the time evolution of the shape of the drop and the flow field inside it is solved by a method of lines using a finite element algorithm incorporating an adaptive mesh. When the forcing amplitude is small, the drop approaches a limit cycle at large times and undergoes steady oscillations thereafter. However, drop breakup is the consequence if the forcing amplitude exceeds a critical value. Over a wide range of amplitudes above this critical value, drop ejection from the rod occurs during the second oscillation period from the commencement of rod motion. Remarkably, the shape of the interface at breakup and the volume of the primary drop formed are insensitive to changes in forcing amplitude. The interface shape at times close to and at breakup is a multi-valued function of distance measured along the rod axis and hence cannot be described by recently popularized one-dimensional approximations. The computations show that drop ejection occurs without the formation of a long neck. Therefore, this method of drop formation holds promise of preventing formation of undesirable satellite droplets.

Wilkes, E. D.; Basaran, O. A.

1999-01-01

369

Piston rod seal for a Stirling engine  

DOEpatents

In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal.

Shapiro, Wilbur (Schenectady, NY)

1984-01-01

370

VIEW EAST, EAST ELEVATION OF ECCENTRIC HOUSE, NOTE ROD LINES ...  

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

VIEW EAST, EAST ELEVATION OF ECCENTRIC HOUSE, NOTE ROD LINES EXITING THE BUILDING AND ROD LINES WITH SUPPORTS IN FOREGROUND LEFT. - South Penn Oil Company, G. M. Mead Lot 492 Lease, Morrison Run Field, Clarendon, Warren County, PA

371

Cosmic string wakes  

SciTech Connect

Accretion of matter onto wakes left behind by horizon-sized pieces of cosmic string is investigated, and the effects of wakes on the large-scale structure of the universe are determined. Accretion of cold matter onto wakes, the effects of a long string on fluids with finite velocity dispersion or sound speeds, the interactions between loops and wakes, and the conditions for wakes to survive disruption by loops are discussed. It is concluded that the most important wakes are those which were formed at the time of equal matter and radiation density. This leads to sheetlike overdense regions of galaxies with a mean separation in agreement with the scale of the bubbles of de Lapparent, Geller, and Huchra (1986). However, for the value of G(mu) favored from galaxy formation considerations in a universe with cold dark matter, a wake accretes matter from a distance of only about 1.5 Mpc, which is much less than the distance between the wakes. 39 references.

Stebbins, A.; Veeraraghavan, S.; Silk, J.; Brandenberger, R.; Turok, N.

1987-11-01

372

Cosmic string wakes  

NASA Technical Reports Server (NTRS)

Accretion of matter onto wakes left behind by horizon-sized pieces of cosmic string is investigated, and the effects of wakes on the large-scale structure of the universe are determined. Accretion of cold matter onto wakes, the effects of a long string on fluids with finite velocity dispersion or sound speeds, the interactions between loops and wakes, and the conditions for wakes to survive disruption by loops are discussed. It is concluded that the most important wakes are those which were formed at the time of equal matter and radiation density. This leads to sheetlike overdense regions of galaxies with a mean separation in agreement with the scale of the bubbles of de Lapparent, Geller, and Huchra (1986). However, for the value of G(mu) favored from galaxy formation considerations in a universe with cold dark matter, a wake accretes matter from a distance of only about 1.5 Mpc, which is much less than the distance between the wakes.

Stebbins, Albert; Veeraraghavan, Shoba; Silk, Joseph; Brandenberger, Robert; Turok, Neil

1987-01-01

373

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

374

Dynamical string tension in string theory with spacetime Weyl invariance  

NASA Astrophysics Data System (ADS)

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 background which suggests previously unimagined directions in the stringy exploration of the very early universe.

Bars, I.; Steinhardt, P. J.; Turok, N.

2014-11-01

375

String Field Theory Solution for Any Open String Background  

E-print Network

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.

Theodore Erler; Carlo Maccaferri

2014-10-04

376

Chitosan rod reinforced by self-crosslinking through thermal treatment  

Microsoft Academic Search

Chitosan (CS) rods were reinforced at high temperatures to form network structure by self-crosslinking of amino groups. Properties\\u000a of treated CS rods were studied by FTIR spectroscopy, intrinsic viscosity measurement, mechanical properties testing and water\\u000a absorption measurement. The FTIR spectra indicated that the CS configuration was transformed from ?-CS for untreated CS rods\\u000a to ?-CS for thermally treated CS rods.

Zheng-ke Wang; Qiao-ling Hu; Ruo-chong Fei; Jia-han Ke; Jia-cong Shen

2008-01-01

377

Articulated rods – a novel class of molecular rods based on oligospiroketals (OSK)  

PubMed Central

Summary We developed a new type of molecular rods consisting of two (or more) rigid units linked by a flexible joint. Consequently we called these constructs articulated rods (ARs). The syntheses of ARs were carried out by a flexible and modular approach providing access to a number of compounds with various functionalizations in terminal positions. First applications were presented with pyrene, cinnamoyl and anthracenyl labelled ARs.

Merkel, Roswitha; Müller, Peter

2015-01-01

378

An inter-laboratory study on the variability in measured concentrations of 17?-estradiol, testosterone, and 11-ketotestosterone in white sucker: implications and recommendations.  

PubMed

Endocrine-disrupting chemicals are exogenous substances that can impact the reproduction of fish, potentially by altering circulating concentrations of 17?-estradiol (E2), testosterone (T), and 11-ketotestosterone (11-KT). Common methods to measure steroids in plasma samples include radioimmunoassays (RIAs) and enzyme-linked immunosorbant assays (ELISAs). The present study examines variability in E2, T, and 11-KT across 8 laboratories measuring reference and pulp mill effluent-exposed white sucker (Catostomus commersoni) plasma. We examine the contribution of assay type (RIA vs ELISA), standardized hormone extraction, location of values on the standard curve (upper and lower limits), and other variables on the ability to distinguish hormone levels between reference and exposed fish and the impact of these variables on quantitation of hormones in different laboratories. Of the 8 participating laboratories, 7 of 8 and 7 of 7 identified differences between sites for female E2 and female T, respectively, and 7 of 7 and 4 of 5 identified no differences between male T and male 11-KT. Notably, however, the ng/mL concentration of steroids measured across laboratories varied by factors of 10-, 6-, 14-, and 10-fold, respectively. Within laboratory intra-assay variability was generally acceptable and below 15%. Factors contributing to interlaboratory variability included calculation errors, assay type, and methodology. Based on the interlaboratory variability detected, we provide guidelines and recommendations to improve the accuracy and precision of steroid measurements in fish ecotoxicology studies. PMID:24375479

Feswick, April; Ankley, Gerald T; Denslow, Nancy; Ellestad, Laura E; Fuzzen, Meghan; Jensen, Kathleen M; Kroll, Kevin; Lister, Andrea; MacLatchy, Deborah L; McMaster, Mark E; Orlando, Edward F; Servos, Mark R; Tetreault, Gerald R; Van Den Heuvel, Michael R; Munkittrick, Kelly R

2014-04-01

379

CYP1A induction and blue sac disease in early life stages of white suckers (Catostomus commersoni) exposed to oil sands.  

PubMed

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 sands, and industrially contaminated (wastewater pond) sediments collected from sites along the Athabasca River, Alberta (Canada). Eggs and larvae were observed for mortality, hatching, deformities, growth, and cytochrome P-4501A (CYP1A) activity using immunohistochemistry. E-Nat-, S-Nat-, and wastewater pond sediment-exposed groups showed significant premature hatching, reduced growth, and exposure-dependent increases in ELS mortality and larval malformations relative to controls. The most common larval deformities included edemas (pericardial, yolk sac, and subepidermal), hemorrhages, and spinal defects. Juveniles exposed to oil sands and wastewater pond sediments (96 h) demonstrated significantly increased 7-ethoxyresorufin-O-deethylase (EROD) activity (30- to 50-fold) as compared to controls. Reference sediment-exposed groups and water controls demonstrated reliable embryo and larval survival, minimal malformations, and negligible CYP1A staining. These observed signs of blue sac disease (ELS mortality, malformations, growth reductions, CYP1A activity induction) may produce deleterious reproductive effects in natural fish populations exposed to oil sands mixtures. PMID:16728374

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

2006-05-01

380

Elastic Rods, Rigid Bodies, Quaternions and the Last Quadrature  

Microsoft Academic Search

The Kirchhoff kinetic analogy relates the governing equations for the statics of elastic rods and the dynamics of rigid bodies. We discuss the analogy in light of several different Hamiltonian formulations, including a non-canonical description of rod equilibria. We focus on the last three quadratures that are required to reconstruct the rod centreline from the frame variables, which form the

S. Kehrbaum; J. H. Maddocks

1997-01-01

381

Viscosity of concentrated suspensions of sphere/rod mixtures  

SciTech Connect

This paper discusses the viscosity of concentrated suspensions of sphere/rod mixtures by adopting the Thomas relations for spheres and Milliken`s for randomly oriented rods with aspect ratio of 20. The relative viscosity of a mixed suspension may now be calculated for any combination of rods (of aspect ratio 20) and spheres.

Mor, R.; Gottlieb, M. [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Chemical Engineering; Graham, A.L. [Los Alamos National Lab., NM (United States); Mondy, L.A.

1996-05-01

382

Simplified modeling of the EBR-II control rods  

Microsoft Academic Search

Simplified models of EBR-II control and safety rods have been developed for core modeling under various operational and shutdown conditions. A parametric study was performed on normal worth, high worth, and safety rod type control rods. A summary of worth changes due to individual modeling approximations is tabulated. Worth effects due to structural modeling simplification are negligible. Fuel region homogenization

1995-01-01

383

Simulation of energized Franklin rods for lightning protection  

Microsoft Academic Search

In this paper, the onset criterion of the upward streamers from an energized Franklin rod is formulated as a function of the geometry of the rod and the height and current of the downward leader. The electric field in the vicinity of the lightning rod is calculated using the charge simulation technique. The dependency of the radius of protection on

Mazen Abdel-Salam; Umar Saleh Al-Abdul-Latif

1997-01-01

384

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

385

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

386

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

387

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

388

Dynamical evolution of cosmic strings  

SciTech Connect

The author have studied by means of numerical simulations the dynamical evolution of a network of cosmic strings, both in the radiation and matter era. Our basic conclusion is that a scaling solution exists, i.e., the string energy density evolves as t/sup -2/. This means that the process by which long strings dump their energy into closed loops (which can gravitationally radiate away) is efficient enough to prevent the string domination over other forms of energy. This conclusion does not depend on the initial string energy density, nor on the various numerical parameters. On the other hand, the generated spectrum of loop sizes does depend on the value of our numerical lower cutoff (i.e., the minimum length of loop we allow to be chopped off the network). Furthermore, the network evolution is very different from what was assumed before), namely the creation of a few horizon sized loops per horizon volume and per hubble time, which subsequently fragment into about 10 smaller daughter loops. Rather, many tiny loops are directly cut from the network of infinite strings, and it appears that the only fundamental scale (the horizon) has been lost. This is probably because a fundamental ingredient had been overlooked, namely the kinks. These kinks are created in pairs at each intercommutation, and very rapidly, the long strings appear to be very kinky. Thus the number of long strings per horizon is still of the order of a few, but their total length is fairly large. Furthermore, a large number of kinks favors the formation of small loops, and their sizes might well be governed by the kink density along the long strings. Finally, we computed the two-point correlation function of the loops and found significant differences from the work of Turok.

Bouchet, F.R.

1988-05-11

389

Homotopy Classification of Bosonic String Field Theory  

NASA Astrophysics Data System (ADS)

We prove the decomposition theorem for the loop homotopy Lie algebra of quantum closed string field theory and use it to show that closed string field theory is unique up to gauge transformations on a given string background and given S-matrix. For the theory of open and closed strings we use results in open-closed homotopy algebra to show that the space of inequivalent open string field theories is isomorphic to the space of classical closed string backgrounds. As a further application of the open-closed homotopy algebra, we show that string field theory is background independent and locally unique in a very precise sense. Finally, we discuss topological string theory in the framework of homotopy algebras and find a generalized correspondence between closed strings and open string field theories.

Münster, Korbinian; Sachs, Ivo

2014-09-01

390

Homotopy Classification of Bosonic String Field Theory  

E-print Network

We prove the decomposition theorem for the loop homotopy algebra of quantum closed string field theory and use it to show that closed string field theory is unique up to gauge transformations on a given string background and given S-matrix. For the theory of open and closed strings we use results in open-closed homotopy algebra to show that the space of inequivalent open string field theories is isomorphic to the space of classical closed string backgrounds. As a further application of the open-closed homotopy algebra we show that string field theory is background independent and locally unique in a very precise sense. Finally we discuss topological string theory in the framework of homotopy algebras and find a generalized correspondence between closed strings and open string field theories.

Korbinian Muenster; Ivo Sachs

2012-08-28

391

Peculiar velocities from cosmic strings  

SciTech Connect

The peculiar velocities with respect to the uniform Hubble expansion which arise in the cosmic-string theory of galaxy formation are estimated analytically and compared to numerical simulations. In contrast with models of formation of structure based on primordial linear energy-density perturbations with random phases the distribution of velocities in the cosmic-string scenario is highly non-Gaussian. The most likely velocities are approximately scale independent for scales smaller than 50h/sup -1/ Mpc. We discuss both the effects of cosmic-string loops and of wakes. The analytical analysis presented in this paper complements earlier work in which the numerical results were presented.

Brandenberger, R.; Kaiser, N.; Shellard, E.P.S.; Turok, N.

1987-07-15

392

Radio bursts from superconducting strings  

NASA Astrophysics Data System (ADS)

We show that radio bursts from cusps on superconducting strings are linearly polarized, thus providing a signature that can be used to distinguish them from astrophysical sources. We write the event rate of string-generated radio transients in terms of observational variables, namely, the event duration and flux. Assuming a canonical set of observational parameters, we find that the burst event rate can be quite reasonable, e.g., order ten a year for grand unified strings with 100 TeV currents, and a lack of observed radio bursts can potentially place strong constraints on particle physics models.

Cai, Yi-Fu; Sabancilar, Eray; Vachaspati, Tanmay

2012-01-01

393

String Theory, Unification and Supersymmetry  

E-print Network

One cannot yet point to any firm string prediction. While many approximate string ground states are known with interesting properties, we do not have any argument that one or another describes what we observe around us, and for reasons which appear fundamental we do not know how to systematically determine even any rough quantitative properties. I argue here that we should examine large classes of string ground states, trying to determine whether features such as low energy supersymmetry, the pattern of supersymmetry breaking, the presence of axions, large dimensions, or others might be generic.

Michael Dine

2002-10-17

394

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

395

Closed string amplitudes as single-valued open string amplitudes  

NASA Astrophysics Data System (ADS)

We show that the single trace heterotic N-point tree-level gauge amplitude ANHET can be obtained from the corresponding type I amplitude ANI by the single-valued (sv) projection: ANHET=sv(ANI). This projection maps multiple zeta values to single-valued multiple zeta values. The latter represent a subclass of multiple zeta values originating from single-valued multiple polylogarithms at unity. Similar relations between open and closed string amplitudes or amplitudes of different string vacua can be established. As a consequence the ??-expansion of a closed string amplitude is dictated by that of the corresponding open string amplitude. The combination of single-valued projections, Kawai-Lewellen-Tye relations and Mellin correspondence reveal a unity of all tree-level open and closed superstring amplitudes together with the maximally supersymmetric Yang-Mills and supergravity theories.

Stieberger, Stephan; Taylor, Tomasz R.

2014-04-01

396

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

397

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

2013-02-11

398

Thermal regimes of high burn-up nuclear fuel rod  

NASA Astrophysics Data System (ADS)

The temperature distribution in the nuclear fuel rods for high burn-up is studied. We use the numerical and analytical approaches. It is shown that the time taken to have the stationary thermal regime of nuclear fuel rod is less than one minute. We can make the inference that the behavior of the nuclear fuel rod can be considered as a stationary task. Exact solutions of the temperature distribution in the fuel rods in the stationary case are found. Thermal regimes of high burn-up the nuclear fuel rods are analyzed.

Kudryashov, Nikolai A.; Khlunov, Aleksandr V.; Chmykhov, Mikhail A.

2010-05-01

399

Rebirth of a control rod at the Phenix power plant  

SciTech Connect

This paper outlines the operations involved in cleaning the control rod for the complementary shutdown system in the Phenix Power Plant, the French sodium-cooled fast reactor. The Phenix reactor is controlled by six control rods and a complementary shutdown system. The latter comprises a control rod and a mechanism maintaining the rod in position by means of an electromagnet. The electromagnet is continuously supplied with power and holds the rod control assembly in position by magnetisation on a plane circular surface made from pure iron. The bearing capacity of the mechanism on the rod was initially 80 daN with a rod weight of 26.3 daN. This deteriorated progressively over time. The bearing surface of the rod and the electromagnet became contaminated with a deposit of sodium oxides and metallic particles, thus creating an air gap. This reached a figure of 36 daN in 2005 and was deemed not to be sufficient to prevent the rod from dropping at the wrong time during reactor operation. The Power Plant thus decided to replace the rod mechanism in the reactor in an initial phase, followed by the control rod itself. As the Phenix Power Plant had no spare control rods left, they initiated a 'salvage' plan, over two stages, for the rod removed from the reactor and placed in the fuel storage drum: - Inspection of the bearing surface of the rod by means of a borescope to check whether the rod could be salvaged, - A cleaning operation on the bearing face and checks on the bearing capacity of the rod. The operation is subject to very stringent requirements: the rod must not be taken out of the sodium to ensure that it can be reused in the reactor. The operation must thus take place in the fuel storage drum where there are no facilities for such an operation and where operating conditions are very hostile: high temperatures (the sodium in the fuel storage drum is at a temperature of 150 deg. C, high dose rate (3 mGy/h on the bearing surface) and the bearing surface is submerged under a metre of sodium. 4 poles will have been required for this operation: - a pole for draining the rod and uncovering the bearing surface, - a borescope pole, - a pole for cleaning the bearing surface, - a pole for inspecting the bearing surface. The operation resulted in a very satisfactory bearing capacity of approx. 80 daN. This paper also examines the history of contamination of the control rod and the rod mechanism. It outlines the hypotheses for the source of this contamination and the measures taken to counteract this problem. (authors)

De Carvalho, Corinne; Vignau, Bernard; Masson, Marc [CEA Nuclear energy division, Phenix plant, BP 17171, 30207 Bagnols sur Ceze (France)

2007-07-01

400

Cosmic string catalysis of skyrmion decay  

SciTech Connect

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, R.; Davis, A.C.; Brandenberger, R.

1988-10-01

401

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

402

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

403

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

404

String Cosmology -- Large-Field Inflation in String Theory  

NASA Astrophysics Data System (ADS)

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 protection against quantum corrections. This makes them ideal candidates for a description in a candidate fundamental theory like string theory. At the same time the need of large-field inflation models for UV completion makes them particularly susceptible to preserve imprints of their string-scale dynamics in the inflationary observables, the spectral index ns and the fractional tensor mode power r. Hence, we will focus this review on axion monodromy inflation as a mechanism of large-field inflation in string theory.

Westphal, Alexander

2014-12-01

405

Perturbations from strings don't look like strings!  

NASA Technical Reports Server (NTRS)

A systematic analysis is challenging popular ideas about perturbation from cosmic strings. One way in which the picture has changed is reviewed. It is concluded that, while the scaling properties of cosmic strings figure significantly in the analysis, care must be taken when thinking in terms of single time snapshots. The process of seeding density perturbations is not fundamentally localized in time, and this fact can wash out many of the details which appear in a single snapshot.

Albrecht, Andreas; Stebbins, Albert

1991-01-01

406

An extended geometric model for analysis of string crossings in bowed-string instrument performance  

E-print Network

crossing angles for stopped strings. The model requires knowledge of the tensions of the strings of the model was that it did not take into account the displacement of stopped strings. This displacement can

Paris-Sud XI, Université de

407

On the metabolism of the rod outer segments.  

PubMed Central

1. The high energy phosphate esters available for the luminescent reaction of the firefly lantern extract correspond, in the dark adapted rods of the frog, to 7 X 10(-16) mole of ATP per rod, corresponding to ca. 1-4 mM. 2. Rods isolated from light adapted eyes contain a smaller amount. 3. The high energy phosphate esters are reduced spontaneously at a rate of 50% in 24 min, in the isolated rods in darkness. 4. Bleaching a few per cent of the rhodopsin molecules of a rod suspension induces a 60% decrease achieved in less than 12 sec. 5. The ionophore A23187 decreases the high energy phosphate esters when the extracellular free Ca concentration is greater than 10(-7) M, suggesting that ATP is consumed in pumping Ca ions out of the rods, or into the disks contained in the rods, or both. PMID:781215

Carretta, A; Cavaggioni, A

1976-01-01

408

Nuclear thermionic converter. [tungsten-thorium oxide rods  

NASA Technical Reports Server (NTRS)

Efficient nuclear reactor thermionic converter units are described which can be constructed at low cost and assembled in a reactor which requires a minimum of fuel. Each converter unit utilizes an emitter rod with a fluted exterior, several fuel passages located in the bulges that are formed in the rod between the flutes, and a collector receiving passage formed through the center of the rod. An array of rods is closely packed in an interfitting arrangement, with the bulges of the rods received in the recesses formed between the bulges of other rods, thereby closely packing the nuclear fuel. The rods are constructed of a mixture of tungsten and thorium oxide to provide high power output, high efficiency, high strength, and good machinability.

Phillips, W. M.; Mondt, J. F. (inventors)

1977-01-01

409

Nuclear reactor fuel rod attachment system  

DOEpatents

A reusable system for removably attaching a nuclear reactor fuel rod (12) to a support member (14). A locking cap (22) is secured to the fuel rod (12) and a locking strip (24) is fastened to the support member (14). The locking cap (22) has two opposing fingers (24a and 24b) shaped to form a socket having a body portion (26). The locking strip has an extension (36) shaped to rigidly attach to the socket's body portion (26). The locking cap's fingers are resiliently deflectable. For attachment, the locking cap (22) is longitudinally pushed onto the locking strip (24) causing the extension (36) to temporarily deflect open the fingers (24a and 24b) to engage the socket's body portion (26). For removal, the process is reversed.

Christiansen, David W. (Kennewick, WA)

1982-01-01

410

A survey of laser lightning rod techniques  

NASA Technical Reports Server (NTRS)

The work done to create a laser lightning rod (LLR) is discussed. Some ongoing research which has the potential for achieving an operational laser lightning rod for use in the protection of missile launch sites, launch vehicles, and other property is discussed. Because of the ease with which a laser beam can be steered into any cloud overhead, an LLR could be used to ascertain if there exists enough charge in the clouds to discharge to the ground as triggered lightning. This leads to the possibility of using LLRs to test clouds prior to launching missiles through the clouds or prior to flying aircraft through the clouds. LLRs could also be used to probe and discharge clouds before or during any hazardous ground operations. Thus, an operational LLR may be able to both detect such sub-critical electrical fields and effectively neutralize them.

Barnes, Arnold A., Jr.; Berthel, Robert O.

1991-01-01

411

Confocal imaging through an endoscopic rod  

NASA Astrophysics Data System (ADS)

Endoscopic rods (such as the Hopkins variety) are based on a tubular design containing a sequence of refractive optical structures1. They are intended to offer a wide angle of view but often at the expense of performance in terms of field curvature. They are used in areas of biomedicine that require visualisation of live tissue at the distal end, enabling clinicians to perform a variety of endoscopy procedures including biopsy. Here we demonstrate a scanning confocal arrangement with the endoscopic rod used as an optical conduit, guiding the investigation beam to a resolution target placed at the distal end and guiding the backscattered light back to the detector. The data presented in this study highlights the possible new contributions of this method to aid Optical Coherence Tomography (OCT) measurements in vivo and what could be expected of its application in terms of scanangle (field of view) and transmission performance.

Galloway, Matt; Gabriel, Kayla; Dobre, George

2014-01-01

412

Polydispersed rods on the square lattice  

NASA Astrophysics Data System (ADS)

We study the grand-canonical solution of a system of hard polydispersed rods placed on the square lattice using transfer matrix and finite-size scaling calculations. We determine the critical line separating an isotropic from a nematic phase. No second transition to a disordered phase is found at high density, contrary to what is observed in the monodispersed case. The estimates of critical exponents and the central charge on the critical line are consistent with the Ising universality class.

Stilck, Jürgen F.; Rajesh, R.

2015-01-01

413

FTK-ROD FLOW CONTROL Anton Kapliy  

E-print Network

firmware #12;Bird's-eye view: S-LINK forward transmission ATLAS Upgrade Week at Stanford. A.Kapliy - 03 (after 8b/10b) S-Link firmware inside HOLA D[32] @ 40 MHz Data from the ROD comes in through a parallel details in a later slide D[1] @ 2 GHz (after 8b/10b) DAQ (ROS+ROBIN) S-Link firmware inside HOLA If FIFO

414

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

415

String theory and quantum chromodynamics  

NASA Astrophysics Data System (ADS)

I review recent progress on the connection between string theory and quantum chromodynamics in the context of the gauge/gravity duality. Emphasis is placed on conciseness and conceptual aspects rather than on technical details. Topics covered include the large-\

Mateos, David

2007-11-01

416

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

417

Quadratic superconducting cosmic strings revisited  

NASA Astrophysics Data System (ADS)

It has been shown that a 5-dimensional general-relativity action extended by appropriate quadratic terms admits a singular superconducting cosmic string solution. We search for cosmic strings endowed with similar and extended physical properties by directly integrating the non-linear matrix field equations thus avoiding the perturbative approach by which we constructed the above-mentioned exact solution. The most general superconducting cosmic string, subject to some constraints, will be derived and shown to be mathematically unique up to linear coordinate transformations mixing its Killing vectors. The most general solution, however, is not globally equivalent to the old one due to the existence of Killing vectors with closed orbits. Contribution under the title of Exact 5-Dimensional Cosmic String Solutions to the International Conference on Dynamics and Thermodynamics of Black Holes and Naked Singularities II, Milan, Italy, May 2007.

Azreg-Aïnou, M.

2008-03-01

418

GUT cosmic strings and inflation  

E-print Network

We show that GUT cosmic strings generically form after inflation if a {\\it non-inert} symmetry breaks after inflation; they form irrespectively of the inflationary scenario and in both supersymmetric and non-supersymmetric theories.

Rachel Jeannerot

2006-08-29

419

Bosonic String and String Field Theory: a solution using the holomorphic representation  

E-print Network

In this paper we show that the holomorphic representation is appropriate for description in a consistent way string and string field theories, when the considered number of component fields of the string field is finite. A new Lagrangian for the closed string is obtained and shown to be equivalent to Nambu-Goto's Lagrangian. We give the notion of anti-string, evaluate the propagator for the string field, and calculate the convolution of two of them.

C. G. Bollini; M. C. Rocca

2009-08-20

420

Incorporation of squalene into rod outer segments  

SciTech Connect

We have reported previously that squalene is the major radiolabeled nonsaponifiable lipid product derived from ({sup 3}H)acetate in short term incubations of frog retinas. In the present study, we demonstrate that newly synthesized squalene is incorporated into rod outer segments under similar in vitro conditions. We show further that squalene is an endogenous constituent of frog rod outer segment membranes; its concentration is approximately 9.5 nmol/mumol of phospholipid or about 9% of the level of cholesterol. Pulse-chase experiments with radiolabeled precursors revealed no metabolism of outer segment squalene to sterols in up to 20 h of chase. Taken together with our previous absolute rate studies, these results suggest that most, if not all, of the squalene synthesized by the frog retina is transported to rod outer segments. Synthesis of protein is not required for squalene transport since puromycin had no effect on squalene incorporation into outer segments. Conversely, inhibition of isoprenoid synthesis with mevinolin had no effect on the incorporation of opsin into the outer segment. These latter results support the conclusion that the de novo synthesis and subsequent intracellular trafficking of opsin and isoprenoid lipids destined for the outer segment occur via independent mechanisms.

Keller, R.K.; Fliesler, S.J. (Univ. of South Florida College of Medicine, Tampa (USA))

1990-08-15

421

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

422

Meson decays from string splitting  

E-print Network

We discuss exclusive decays of large spin mesons into mesons in models of large N_c quenched QCD at strong coupling using string theory. The rate of the processes are calculated by studying the splitting of a macroscopic string on the relevant dual gravity backgrounds. We study analytic formulas for the decay rates of mesons made up of very heavy or very light quarks.

F. Bigazzi; A. L. Cotrone; L. Martucci; W. Troost

2006-11-23

423

Elliptic genera of monopole strings  

NASA Astrophysics Data System (ADS)

We obtain elliptic genera of monopole string in 5d MSYM. We find agreement with the corresponding TST-dual dyonic-instanton single particle indices in arXiv:1110.2175. We make use of (2,2) superconformal algebra and its spectral flow, and the agreement can therefore be taken as evidence that monopole string (4,4) sigma models are exactly quantum superconformal.

Bak, Dongsu; Gustavsson, Andreas

2015-01-01

424

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

425

Aggregation behavior of rod-coil-rod triblock copolymers in a coil-selective solvent.  

PubMed

Recent experiments have reported that the self-assembly of conjugated polymers mimicking rod-coil-rod triblock copolymers (BCPs) in selective solvents exhibits unique aggregate morphologies. However, the nature of the arrangement of the polymers within the aggregates and the spatial organization of the aggregates remain an unresolved issue. We report the results of coarse-grained Langevin dynamics simulations, which investigated the self-assembly behavior of rod-coil-rod BCPs in a coil-selective solvent. We observe a rapid formation of cylindrically shaped multichain clusters. The initial stages of formation of the aggregates was seen to be independent of the strength of the solvent selectivity. However, for higher solvent selectivities, the clusters were seen to merge into larger units at later stages. A reduction in rod to coil block ratio was observed to decrease the size and number of clusters. In the limit of a highly concentrated solution, we observe the formation of a networked system of distinct clusters, which however retain the cylindrical arrangement observed at lower polymer concentrations. PMID:25513935

Omar, Ahmad K; Hanson, Ben; Haws, Ryan T; Hu, Zhongjian; Vanden Bout, David A; Rossky, Peter J; Ganesan, Venkat

2015-01-01

426

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

427

Form of cosmic string cusps  

NASA Astrophysics Data System (ADS)

We classify the possible shapes of cosmic string cusps and how they transform under Lorentz boosts. A generic cusp can be brought into a form in which the motion of the cusp tip lies in the plane of the cusp. The cusp whose motion is perpendicular to this plane, considered by some authors, is a special case and not the generic situation. We redo the calculation of the energy in the region where the string overlaps itself near a cusp, which is the maximum energy that can be released in radiation. We take into account the motion of a generic cusp and the resulting Lorentz contraction of the string core. The result is that the energy scales as rL instead of the usual r1/3L2/3, where r is the string radius and L is the typical length scale of the string. Since r<strings, the radiation is strongly suppressed and could not be observed.

Blanco-Pillado, J. J.; Olum, Ken D.

1999-03-01

428

Spherical Joint Piston and Connecting Rod Developed  

NASA Technical Reports Server (NTRS)

Under an interagency agreement with the Department of Energy, the NASA Lewis Research Center manages a Heavy-Duty Diesel Engine Technology (HDET) research program. The overall program objectives are to reduce fuel consumption through increased engine efficiency, reduce engine exhaust emissions, and provide options for the use of alternative fuels. The program is administered with a balance of research contracts, university research grants, and focused in-house research. The Cummins Engine Company participates in the HDET program under a cost-sharing research contract. Cummins is researching and developing in-cylinder component technologies for heavy-duty diesel engines. An objective of the Cummins research is to develop technologies for a low-emissions, 55-percent thermal efficiency (LE-55) engine. The best current-production engines in this class achieve about 46-percent thermal efficiency. Federal emissions regulations are driving this technology. Regulations for heavy duty diesel engines were tightened in 1994, more demanding emissions regulations are scheduled for 1998, and another step is planned for 2002. The LE-55 engine emissions goal is set at half of the 1998 regulation level and is consistent with plans for 2002 emissions regulations. LE-55 engine design requirements to meet the efficiency target dictate a need to operate at higher peak cylinder pressures. A key technology being developed and evaluated under the Cummins Engine Company LE-55 engine concept is the spherical joint piston and connecting rod. Unlike conventional piston and connecting rod arrangements which are joined by a pin forming a hinged joint, the spherical joint piston and connecting rod use a ball-and-socket joint. The ball-and-socket arrangement enables the piston to have an axisymmetric design allowing rotation within the cylinder. The potential benefits of piston symmetry and rotation are reduced scuffing, improved piston ring sealing, improved lubrication, mechanical and thermal load symmetry, reduced bearing stresses, reduced running clearances, and reduced oil consumption. The spherical joint piston is a monolithic, squeeze-cast, fiber-reinforced aluminum piston. The connecting rod has a ball end that seats on a spherical saddle within the piston and is retained by a pair of aluminum bronze holder rings. The holder rings are secured by a threaded ring that mates with the piston. As part of the ongoing research and development activity, the Cummins Engine Company successfully completed a 100-hr test of the spherical joint piston and connecting rod at LE- 55 peak steady-state engine conditions. In addition, a 100-hr transient cycle test that varied engine conditions between LE-55 no-load and LE-55 full-load was successfully completed.

1996-01-01

429

Preliminary Study of the Effect of the Proposed Long Lake Valley Project Operation on the Transport of Larval Suckers in Upper Klamath Lake, Oregon  

USGS Publications Warehouse

A hydrodynamic model of Upper Klamath and Agency Lakes, Oregon, was used to explore the effects of the operation of proposed offstream storage at Long Lake Valley on transport of larval suckers through the Upper Klamath and Agency Lakes system during May and June, when larval fish leave spawning sites in the Williamson River and springs along the eastern shoreline and become entrained in lake currents. A range in hydrologic conditions was considered, including historically high and low outflows and inflows, lake elevations, and the operation of pumps between Upper Klamath Lake and storage in Long Lake Valley. Two wind-forcing scenarios were considered: one dominated by moderate prevailing winds and another dominated by a strong reversal of winds from the prevailing direction. On the basis of 24 model simulations that used all combinations of hydrology and wind forcing, as well as With Project and No Action scenarios, it was determined that the biggest effect of project operations on larval transport was the result of alterations in project management of the elevation in Upper Klamath Lake and the outflow at the Link River and A Canal, rather than the result of pumping operations. This was because, during the spring time period of interest, the amount of water pumped between Upper Klamath Lake and Long Lake Valley was generally small. The dominant effect was that an increase in lake elevation would result in more larvae in the Williamson River delta and in Agency Lake, an effect that was enhanced under conditions of wind reversal. A decrease in lake elevation accompanied by an increase in the outflow at the Link River had the opposite effect on larval concentration and residence time.

Wood, Tamara M.

2009-01-01

430

Constituents within pulp mill effluent deplete retinoid stores in white sucker and bind to rainbow trout retinoic acid receptors and retinoid X receptors.  

PubMed

Wild female and male white sucker (Catostomus commersoni) inhabiting an area receiving pulp mill effluent had reduced hepatic levels of retinol, didehydroretinol, retinyl esters, and didehydroretinyl esters, while vitamin E levels were unaffected. This disruption of the retinoid system led us to test methanol and dichloromethane extracts from the effluent of 11 pulp mills from across Canada for their ability to bind to rainbow trout (Oncorhynchus mykiss) retinoic acid receptors (RARs) from the gill and retinoid X receptors (RXRs) from the liver. Concentrated extracts of the final effluent from 6 of the 11 pulp mills were able to displace greater than 25% of the receptor-bound [3H]all-trans retinoic acid (RA) or [3H]9-cis RA from trout RARs and RXRs, respectively. The ability of the extracts to displace retinoic acid did not appear to be linked to the pulping or treatment processes. Moreover, extracts with the greatest activity came from thermomechanical mills, suggesting the compounds may originate from the wood furnish. In addition, extracts prepared from wood furnish (wood chips: white spruce [50%], lodgepole pine [47%], and balsam fir [3%]) from one mill were able to displace [3H]RA from the RARs and RXRs. The 4-hydroxy RA, a metabolite of RA that has been shown to be generated in greater quantities in fish exposed to P450-inducing xenobiotics, was able to displace [3H]all-trans RA from trout RARs as effectively as unlabeled all-trans RA. These results suggest that pulp mill effluent may impact the retinoid system of fish at multiple sites, either by decreasing hepatic retinoid stores or through contributing additional ligands (from the wood furnish) that can bind to RA receptors. PMID:14713038

Alsop, Derek; Hewitt, Mark; Kohli, Mohan; Brown, Scott; Van Der Kraak, Glen

2003-12-01

431

Assessing reproductive and endocrine parameters in male largescale suckers (Catostomus macrocheilus) along a contaminant gradient in the lower Columbia River, USA.  

PubMed

Persistent organochlorine pollutants such as polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (p,p'-DDE), and polybrominated diphenyl ethers (PBDEs) are stable, bioaccumulative, and widely found in the environment, wildlife, and the human population. To explore the hypothesis that reproduction in male fish is associated with environmental exposures in the lower Columbia River (LCR), reproductive and endocrine parameters were studied in male resident, non-anadromous largescale sucker (Catostomus macrocheilus) (LSS) in the same habitats as anadromous salmonids having conservation status. Testes, thyroid tissue and plasma collected in 2010 from Longview (LV), Columbia City (CC), and Skamania (SK; reference) were studied. Sperm morphologies and thyrocyte heights were measured by light microscopy, sperm motilities by computer-assisted sperm motion analysis, sperm adenosine triphosphate (ATP) with luciferase, and plasma vitellogenin (VTG), thyroxine (T4), and triiodothyronine (T3) by immunoassay. Sperm apoptosis, viability, mitochondrial membrane potential, nuclear DNA fragmentation, and reproductive stage were measured by flow cytometry. Sperm quality parameters (except counts) and VTG were significantly different among sites, with correlations between VTG and 7 sperm parameters. Thyrocyte heights, T4, T3, gonadosomatic index and Fulton's condition factor differed among sites, but not significantly. Sperm quality was significantly lower and VTG higher where liver contaminants and water estrogen equivalents were highest (LV site). Total PCBs (specifically PCB-138, -146, -151, -170, -174, -177, -180, -183, -187, -194, and -206) and total PBDEs (specifically BDE-47, -100, -153, and -154) were negatively correlated with sperm motility. PCB-206 and BDE-154 were positively correlated with DNA fragmentation, and pentachloroanisole and VTG were positively correlated with sperm apoptosis and negatively correlated with ATP. BDE-99 was positively correlated with sperm counts and motility; T4 was negatively correlated with counts and positively correlated with motility, thus indicating possible androgenic mechanisms and thyroid endocrine disruption. Male LSS proved to be an informative model for studying reproductive and endocrine biomarkers in the LCR. PMID:24182618

Jenkins, J A; Olivier, H M; Draugelis-Dale, R O; Eilts, B E; Torres, L; Patiño, R; Nilsen, E; Goodbred, S L

2014-06-15

432

Chronic toxicity of un-ionized ammonia to early life-stages of endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus) compared to the surrogate fathead minnow (Pimephales promelas)  

USGS Publications Warehouse

Ammonia-contaminated groundwater enters the Upper Colorado River from beneath the abandoned Moab Uranium Mill Tailings Pile near Moab, Utah. This reach of the Upper Colorado River was designated as critical habitat for four endangered fish species because it is one of the few existing areas with known spawning and rearing habitats. Un-ionized ammonia (NH3) concentrations frequently exceed 1.00 mg/L in backwaters adjacent to the tailings pile, which exceeds the Utah 30-d average chronic water quality criterion for un-ionized ammonia (0.07 mg/L NH3; temperature 20??C; pH 8.2) by a factor of more than 10. However, there is little published information regarding the sensitivity of endangered fishes to ammonia. We conducted 28-d static renewal studies with post-swim-up larvae to determine the relative sensitivity of Colorado pikeminnow (Ptychocheilus lucius), razorback sucker (Xyrauchen texanus), and the standard surrogate fathead minnow (Pimephales promelas) to NH3. Chronic values (ChVs) for mortality and growth were determined as the geometric mean of the no observed effect concentration and the lowest observed effect concentration based on analysis of variance. The ChVs for growth of fathead minnow, Colorado pikeminnow, and razorback sucker were 0.43, 0.40, and 0.67 mg/L NH3, respectively. The ChVs for mortality of fathead minnow, Colorado pikeminnow, and razorback sucker were 0.43, 0.70, and 0.67 mg/L NH3, respectively. Therefore, the ChVs for mortality and growth were similar for fathead minnow and razorback sucker; however, the ChV for growth was lower than the ChV for mortality for Colorado pikeminnow. Maximum likelihood regression was used to calculate 28-d lethal concentrations (LCx) for each species. The 28-d LC50, LC20, and LC1 values for fathead minnow were 0.69, 0.42, and 0.13 mg/L NH3, respectively. The 28-d LC50, LC20, and LC1 values for Colorado pikeminnow were 0.76, 0.61, and 0.38 mg/L NH3, respectively. The 28-d LC50, LC20, and LC1 values for razorback sucker were 0.54, 0.38, and 0.25 mg/L NH3, respectively. The fathead minnow, Colorado pikeminnow, and razorback sucker are relatively similar in sensitivity and rank at the 35th, 49th, and 31st percentiles, respectively, of the theoretical chronic fish sensitivity distributions for NH3. The existing water quality criteria for NH3, if met by remediation activities at the Moab site, would be protective of these endangered fishes even if fish sensitivity is based on the conservative LC1 value. ?? 2005 Springer Science+Business Media, Inc.

Fairchild, J.F.; Allert, A.L.; Sappington, L.C.; Waddell, B.

2005-01-01

433

Intercommutation of Semilocal Strings and Skyrmions  

SciTech Connect

We study the intercommuting of semilocal strings and Skyrmions for a wide range of internal parameters, velocities, and intersection angles by numerically evolving the equations of motion. We find that the collisions of strings and strings, strings and Skyrmions, and Skyrmions and Skyrmions all lead to intercommuting for a wide range of parameters. Even the collisions of unstable Skyrmions and strings lead to intercommuting, demonstrating that the phenomenon of intercommuting is very robust, extending to dissimilar field configurations that are not stationary solutions. Even more remarkably, at least for the semilocal U(2) formulation considered here, all intercommutations trigger a reversion to Nielsen-Olesen strings.

Laguna, Pablo; Natchu, Vishnu; Matzner, Richard A.; Vachaspati, Tanmay [Department of Astronomy and Astrophysics, IGPG, CGWP, Penn State University, University Park, Pennsylvania 16802 (United States); Center for Relativity, Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States); CERCA, Department of Physics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106-7079 (United States)

2007-01-26

434

String spreading on a black hole horizon  

NASA Astrophysics Data System (ADS)

The phenomenon of string spreading on the black hole horizon, as originally discussed by Susskind, is considered in the exact curved Schwarzschild background. We consider an oscillating macroscopic string encircling the black hole and contracting towards the horizon. We then compute the angular and radial spreading of the string, as seen by a static observer at spatial infinity using fixed finite resolution time. Within our case study we find that there is indeed a spreading of the string in the angular direction, such that the string eventually covers the whole horizon. However, regarding the radial direction, we find that Lorentz-contraction suppresses the radial string spreading.

Larsen, A. L.; Nicolaidis, A.

1999-07-01

435

An Exact Bosonization Rule for c=1 Noncritical String Theory  

E-print Network

We construct a string field theory for c=1 noncritical strings using the loop variables as the string field. We show how one can express the nonrelativistic free fermions which describes the theory, in terms of these string fields.

N. Ishibashi; A. Yamaguchi

2007-08-28

436

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

437

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 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

2014-10-13

438

High-yield production of hydrophobins RodA and RodB from Aspergillus fumigatus in Pichia pastoris.  

PubMed

Hydrophobins are small fungal proteins with amphipatic properties and the ability to self-assemble on a hydrophobic/hydrophilic interface; thus, many technical applications for hydrophobins have been suggested. The pathogenic fungus Aspergillus fumigatus expresses the hydrophobins RodA and RodB on the surface of its conidia. RodA is known to be of importance to the pathogenesis of the fungus, while the biological role of RodB is currently unknown. Here, we report the successful expression of both hydrophobins in Pichia pastoris and present fed-batch fermentation yields of 200-300 mg/l fermentation broth. Protein bands of expected sizes were detected by SDS-PAGE and western blotting, and the identity was further confirmed by tandem mass spectrometry. Both proteins were purified using his-affinity chromatography, and the high level of purity was verified by silver-stained SDS-PAGE. Recombinant RodA as well as rRodB were able to convert a glass surface from hydrophilic to hydrophobic similar to native RodA, but only rRodB was able to decrease the hydrophobicity of a Teflon-like surface to the same extent as native RodA, while rRodA showed this ability to a lesser extent. Recombinant RodA and native RodA showed a similar ability to emulsify air in water, while recombinant RodB could also emulsify oil in water better than the control protein bovine serum albumin (BSA). This is to our knowledge the first successful expression of hydrophobins from A. fumigatus in a eukaryote host, which makes it possible to further characterize both hydrophobins. Furthermore, the expression strategy and fed-batch production using P. pastoris may be transferred to hydrophobins from other species. PMID:21468704

Pedersen, Mona Højgaard; Borodina, Irina; Moresco, Jacob Lange; Svendsen, Winnie Edith; Frisvad, Jens Christian; Søndergaard, Ib

2011-06-01

439

Tachyon Dynamics in Open String Theory  

E-print Network

In this review we describe our current understanding of the properties of open string tachyons on an unstable D-brane or brane-antibrane system in string theory. The various string theoretic methods used for this study include techniques of two dimensional conformal field theory, open string field theory, boundary string field theory, non-commutative solitons etc. We also describe various attempts to understand these results using field theoretic methods. These field theory models include toy models like singular potential models and p-adic string theory, as well as more realistic version of the tachyon effective action based on Dirac-Born-Infeld type action. Finally we study closed string background produced by the `decaying' unstable D-branes, both in the critical string theory and in the two dimensional string theory, and describe the open string completeness conjecture that emerges out of this study. According to this conjecture the quantum dynamics of an unstable D-brane system is described by an internally consistent quantum open string field theory without any need to couple the system to closed strings. Each such system can be regarded as a part of the `hologram' describing the full string theory.

Ashoke Sen

2004-11-02

440

Vibration of the Package of Rods Linked by Spacer Grids  

NASA Astrophysics Data System (ADS)

This paper deals with modelling and vibration analysis of the large package of identical parallel rods which are linked by transverse springs (spacer grids) placed on several level spacings. The vibration of rods is caused by the support plate motion. The rod discretization by FEM is based on Rayleigh beam theory. With respect to cyclic and central package rod symmetry, the system is decomposed to identical revolved rod segments. The modal synthesis method with condensation of the rod segments is used for modelling and determination of steady forced vibration of the whole system. The presented method is the first step to modelling of the nuclear fuel assembly vibration caused by kinematical excitation determined by motion of the support plates which are part of the reactor core.

Zeman, V.; Hlavá?, Z.

441

Maintenance of BWR control rod drive mechanisms  

SciTech Connect

Control rod drive mechanism (CRDM) replacement and rebuilding is one of the highest dose, most physically demanding, and complicated maintenance activities routinely accomplished by BWR utilities. A recent industry workshop sponsored by the Oak Ridge National Laboratory, which dealt with the effects of CRDM aging, revealed enhancements in maintenance techniques and tooling which have reduced ALARA, improved worker comfort and productivity, and have provided revised guidelines for CRDM changeout selection. Highlights of this workshop and ongoing research on CRDM aging are presented in this paper.

Greene, R.H.

1991-01-01

442

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. Physically, our results provide a Fermi gas picture of topological strings on toric Calabi-Yau manifolds, which is fully non-perturbative and background independent. They also suggest the existence of an underlying theory of M2 branes behind this formulation. Mathematically, our results lead to precise, surprising conjectures relating the spectral theory of functional difference operators to enumerative geometry.

Alba Grassi; Yasuyuki Hatsuda; Marcos Marino

2014-11-27

443

Radially stabilized inflating cosmic strings  

E-print Network

In General Relativity, cosmic strings are well known to produce a static, locally flat spacetime with a wedge removed. If the tension exceeds a critical value, the deficit angle becomes larger than $ 2\\pi $, leading to a compact exterior that ends in a conical singularity. In this work, we investigate dynamical solutions for cosmic strings with super-critical tensions. To this end, we model the string as a cylindrical shell of finite and stabilized transverse width and show that there is a marginally super-critical regime in which the stabilization can be achieved by physically reasonable matter. We show numerically that the static deficit angle solution is unstable for super-critical string tensions. Instead, the geometry starts expanding in axial direction at an asymptotically constant rate, and a horizon is formed in the exterior, which has the shape of a growing cigar. We are able to find the analytic form of the attractor solution describing the interior of the cosmic string. In particular, this enables ...

Niedermann, Florian

2014-01-01

444

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

445

Identification of differentially expressed genes in carp rods and cones  

PubMed Central

Purpose Rods and cones differ in their photoresponse characteristics, morphology, and susceptibilities to certain diseases. To contribute to the studies at the molecular level of these differences, we tried to identify genes expressed preferentially in rods or cones. Methods From purified carp rods and cones, we extracted their RNA and obtained corresponding cDNA pools (rod cDNA and cone cDNA). We employed the suppression subtractive hybridization method to identify the genes expressed preferentially in rods or cones. Cone cDNA was subtracted from rod cDNA to obtain cDNA, which ideally contained cDNA expressed preferentially in rods (R/c cDNA). Similarly, rod cDNA was subtracted from cone cDNA to obtain C/r cDNA. With differential array screening, we screened candidate genes that were expressed mainly or exclusively in rods or cones. The nucleotide sequences of the positive genes were determined. In some of them, their mRNA localizations were confirmed by in situ hybridization. Results R/c cDNA contained genes already known to code rod specific proteins, such as cGMP gated channel, transducin ?1, and rhodopsin. In sharp contrast, C/r cDNA contained genes that code proteins of which functions are mostly unknown. Among them, N-myc downregulated gene 1-like (NDRG1L) and aryl hydrocarbon receptor 2 (AhR2) were most abundant, and by in situ hybridization, they were proven to be expressed specifically in cones. Conclusions Using purified rods and cones, we identified mRNAs expressed preferentially in rods or cones. Of particular interest is the specific expression of NDRG1L and AhR2 in cones. PMID:18334952

Shimauchi-Matsukawa, Yoshie; Aman, Yoshinobu; Tachibanaki, Shuji

2008-01-01

446

Surfaces of Rod Photoreceptor Light-activated Enzymes Disk Membranes  

Microsoft Academic Search

The light-activated GTP-binding protein (GBP) in toad rod outer segments has been located on the cytoplasmic surface (CS) of rod disk membranes by correlating biochemical results with images of quick-frozen, freeze-fractured, and deep-etched rod outer segments. This has been accomplished by selectively removing and replacing the 8-12-nm particles that are found on the CS of disk membranes, exactly in parallel

DOROTHY J. ROOF; JUAN I. KORENBROT; JOHN E. HEUSER

447

Failure of expansion joint tie rods -- Impact on bellows integrity  

SciTech Connect

Expansion joints are used in piping systems to accomodate pipe deflections during service and to facilitate fitup. Often, tie rods are employed to limit the range of axial deflection. Additional restraint against excessive displacement can be provided by the surrounding pipe and associated supports. This paper presents a methodology that was employed to estimate the consequences of tie rod failure. Of particular interest is whether tie rod failure can lead to sufficient displacement as to cause bellows rupture.

Daugherty, W.L.; Miller, R.F.

1992-01-01

448

Failure of expansion joint tie rods -- Impact on bellows integrity  

SciTech Connect

Expansion joints are used in piping systems to accomodate pipe deflections during service and to facilitate fitup. Often, tie rods are employed to limit the range of axial deflection. Additional restraint against excessive displacement can be provided by the surrounding pipe and associated supports. This paper presents a methodology that was employed to estimate the consequences of tie rod failure. Of particular interest is whether tie rod failure can lead to sufficient displacement as to cause bellows rupture.

Daugherty, W.L.; Miller, R.F.

1992-12-31

449

The delivery and uptake of nicotine from an aerosol rod.  

PubMed Central

Nicotine aerosol rods were assessed for their possible usefulness as substitutes for cigarettes. Under standard FTC conditions, the per puff delivery of the aerosol rod averaged 0.3 micrograms nicotine/puff after 10 puffs and 6.4 micrograms nicotine/puff after 60 puffs. After puffing on the rods, no nicotine was detected in the plasma or urine of seven subjects. PMID:3766836

Sepkovic, D W; Colosimo, S G; Axelrad, C M; Adams, J D; Haley, N J

1986-01-01

450

Rod Packings and Metal-Organic Frameworks Constructed from Rod-Shaped Secondary Building Units  

E-print Network

" of the underlying net. MOFs based on discrete shapes (triangles, squares, tetrahedra, etc.) have been synthesized-organic frameworks (MOFs). Accordingly, we present the preparation, characterization, and crystal structures of 14 new MOFs (named MOF-69A-C and MOF-70-80) of 12 different structure types, belonging to rod packing

Yaghi, Omar M.

451

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

452

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

453

Interaction rates in string gas cosmology  

SciTech Connect

We study string interaction rates in the Brandenberger-Vafa scenario, the very early universe cosmology of a gas of strings. This cosmology starts with the assumption that all spatial dimensions are compact and initially have string scale radii; some dimensions grow due to some thermal or quantum fluctuation which acts as an initial expansion velocity. Based on simple arguments from the low-energy equations of motion and string thermodynamics, we demonstrate that the interaction rates of strings are negligible, so the common assumption of thermal equilibrium cannot apply. We also present a new analysis of the cosmological evolution of strings on compact manifolds of large radius. Then we discuss modifications that should be considered to the usual Brandenberger-Vafa scenario. To confirm our simple arguments, we give a numerical calculation of the annihilation rate of winding strings. In calculating the rate, we also show that the quantum mechanics of strings in small spaces is important.

Danos, Rebecca; Frey, Andrew R.; Mazumdar, Anupam [Department of Physics, University of California, Los Angeles, Los Angeles, California 90095 (United States); California Institute of Technology, 452-48, Pasadena, California 91125 (United States); NORDITA, Blegdamsvej-17, DK-2100, Copenhagen (Denmark)

2004-11-15

454

Interaction rates in string gas cosmology  

NASA Astrophysics Data System (ADS)

We study string interaction rates in the Brandenberger-Vafa scenario, the very early universe cosmology of a gas of strings. This cosmology starts with the assumption that all spatial dimensions are compact and initially have string scale radii; some dimensions grow due to some thermal or quantum fluctuation which acts as an initial expansion velocity. Based on simple arguments from the low-energy equations of motion and string thermodynamics, we demonstrate that the interaction rates of strings are negligible, so the common assumption of thermal equilibrium cannot apply. We also present a new analysis of the cosmological evolution of strings on compact manifolds of large radius. Then we discuss modifications that should be considered to the usual Brandenberger-Vafa scenario. To confirm our simple arguments, we give a numerical calculation of the annihilation rate of winding strings. In calculating the rate, we also show that the quantum mechanics of strings in small spaces is important.

Danos, Rebecca; Frey, Andrew R.; Mazumdar, Anupam

2004-11-01

455

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

456

Energy and Momentum Transport in String Waves  

ERIC Educational Resources Information Center

Formulas are derived for the energy, momentum, and angular momentum transmitted by waves of arbitrary shape in an inextensible string by pure transverse waves in a string using Tait's procedure. (Author/CP)

Juenker, D. W.

1976-01-01

457

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

458

The heterotic string is a soliton  

Microsoft Academic Search

It is shown that the Type IIA superstring compactified on K3 has a smooth string soliton with the same zero mode structure as the heterotic string compactified on a four-torus, thus providing new evidence for a conjectured exact duality between the two six-dimensional string theories. The chiral worldsheet bosons arise as zero modes of Ramond-Ramond fields of the IIA string

Jeffrey A. Harvey; Andrew Strominger

1996-01-01

459

Twenty-five questions for string theorists  

SciTech Connect

In an effort to promote communication between the formal and phenomenological branches of the high-energy theory community, we provide a description of some important issues in supersymmetric and string phenomenology. We describe each within the context of string constructions, illustrating them with specific examples where applicable. Each topic culminates in a set of questions that we believe are amenable to direct consideration by string theorists, and whose answers we think could help connect string theory and phenomenology.

Binetruy, Pierre; /Orsay, LPT; Kane, G.L.; /Michigan U., MCTP; Lykken, Joseph D.; /Fermilab; Nelson, Brent D.; /Pennsylvania U.

2005-09-01

460

Topological Open Strings on Orbifolds  

NASA Astrophysics Data System (ADS)

We use the remodeling approach to the B-model topological string in terms of recursion relations to study open string amplitudes at orbifold points. To this end, we clarify modular properties of the open amplitudes and rewrite them in a form that makes their transformation properties under the modular group manifest. We exemplify this procedure for the {{mathbb C}^3/{mathbb Z}_3} orbifold point of local {{mathbb P}^2}, where we present results for topological string amplitudes for genus zero and up to three holes, and for the one-holed torus. These amplitudes can be understood as generating functions for either open orbifold Gromov-Witten invariants of {{mathbb C}^3/{mathbb Z}_3}, or correlation functions in the orbifold CFT involving insertions of both bulk and boundary operators.

Bouchard, Vincent; Klemm, Albrecht; Mariño, Marcos; Pasquetti, Sara

2010-06-01

461

Bosonic string theory with dust  

E-print Network

We study a modified bosonic string theory that has a pressureless ``dust'' field on the string worldsheet. The dust is a real scalar field with unit gradient which breaks conformal invariance. Hamiltonian analysis reveals a time reparametrization constraint linear in the dust field momentum and a spatial diffeomorphism constraint. This feature provides a natural ``dust time" gauge in analogy with the parametrized particle. In this gauge we give a Fock quantization of the theory, which is complete and self-consistent in d<26. The Hamiltonian of the theory is not a constraint; as a consequence the Hilbert space and mass spectrum are characterized by an additional parameter, and includes the usual string spectrum as a special case. The other sectors provide new particle spectra, some of which do not have tachyons.

Jack Gegenberg; Viqar Husain

2014-03-04

462

Bosonic string theory with dust  

NASA Astrophysics Data System (ADS)

We study a modified bosonic string theory that has a pressureless ‘dust’ field on the string worldsheet. The dust is a real scalar field with unit gradient which breaks conformal invariance. Hamiltonian analysis reveals a time reparametrization constraint linear in the dust field momentum and a spatial diffeomorphism constraint. This feature provides a natural ‘dust time’ gauge in analogy with the parametrized particle. In this gauge we give a Fock quantization of the theory, which is complete and self-consistent in d < 26. The Hamiltonian of the theory is not a constraint; as a consequence the Hilbert space and mass spectrum are characterized by an additional parameter, and includes the usual string spectrum as a special case. The other sectors provide new particle spectra, some of which do not have tachyons.

Gegenberg, Jack; Husain, Viqar

2014-04-01

463

Laser decontamination of the radioactive lightning rods  

NASA Astrophysics Data System (ADS)

Between 1970 and 1980 Brazil experienced a significant market for radioactive lightning rods (RLR). The device consists of an air terminal with one or more sources of americium-241 attached to it. The sources were used to ionize the air around them and to increase the attraction of atmospheric discharges. Because of their ineffectiveness, the nuclear regulatory authority in Brazil suspended the license for manufacturing, commerce and installation of RLR in 1989, and determined that the replaced RLR were to be collected to a centralized radioactive waste management facility for treatment. The first step for RLR treatment is to remove the radioactive sources. Though they can be easily removed, some contaminations are found all over the remaining metal scrap that must decontaminated for release, otherwise it must be treated as radioactive waste. Decontamination using various chemicals has proven to be inefficient and generates large amounts of secondary wastes. This work shows the preliminary results of the decontamination of 241Am-contaminated metal scrap generated in the treatment of radioactive lightning rods applying laser ablation. A Nd:YAG nanoseconds laser was used with 300 mJ energy leaving only a small amount of secondary waste to be treated.

Potiens, A. J.; Dellamano, J. C.; Vicente, R.; Raele, M. P.; Wetter, N. U.; Landulfo, E.

2014-02-01

464

Application of polyimide actuator rod seals  

NASA Technical Reports Server (NTRS)

Development of polyimide two-stage hydraulic actuator rod seals for application in high-performance aircraft was accomplished. The significant portion of the effort was concentrated on optimization of the chevron and K-section second-stage seal geometries to satisfy the requirements for operation at 450 K (350 F) with dynamic pressure loads varying between 200 psig steady-state and 1500 psig impulse cycling. Particular significance was placed on reducing seal gland dimension by efficiently utilizing the fatigue allowables of polyimide materials. Other objectives included investigation of pressure balancing techniques for first-stage polyimide rod seals for 4000 psig 450 K(350 F) environment and fabrication of a modular retainer for the two-stage combination. Seals were fabricated in 0.0254 m (1.0in.) and 0.0635 m (2.5in.) sizes and tested for structural integrity, frictional resistance, and endurance life. Test results showed that carefully designed second stages using polyimides could be made to satisfy the dynamic return pressure requirements of applications in high-performance aircraft. High wear under full system pressure indicated that further research is necessary to obtain an acceptable first-stage design. The modular retainer was successfully tested and showed potential for new actuator applications.

Watermann, A. W.; Gay, B. F.; Robinson, E. D.; Srinath, S. K.; Nelson, W. G.

1972-01-01

465

Vertex interactions in string field theory  

NASA Astrophysics Data System (ADS)

The vertex interactions of open and closed strings are constructed. This allows for unique gauge invariant string actions. Further, the equivalence of our models with recent results on string interactions is discussed. I thank R. Brandenberger, P. Goddard and C. Hull for stimulating discussions and C.J. Isham for his support during the course of this work.

Awada, M. A.

1986-11-01

466

From Quantum Mechanics to String Theory  

E-print Network

From Quantum Mechanics to String Theory Relativity (why it makes sense) Quantum mechanics and the Strong Force Symmetry and Unification String Theory: a different kind of unification Extra Dimensions Strings and the Strong Force Thursday, May 7, 2009 #12;Review of Quantum Mechanics In general, particles

467

From Quantum Mechanics to String Theory  

E-print Network

From Quantum Mechanics to String Theory Relativity (why it makes sense) Quantum mechanics and the Strong Force Symmetry and Unification String Theory: a different kind of unification Extra Dimensions Strings and the Strong Force Thursday, May 7, 2009 #12;Relativity (Why it makes sense) Thursday, May 7

468

Vacuumless cosmic strings in Einstein Cartan theory  

E-print Network

The gravitational fields of vacuumless global and gauge strings have been investigated in the context of Einstein Cartan theory under the weak field assumption of the field equations. It has been shown that global string and gauge string can have only repulsive gravitational effect on a test particle.

F. Rahaman; B. C. Bhui; A Ghosh; R. Mondal

2006-10-20

469

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 Extra Dimensions Strings and the Strong Force Friday, May 15, 2009 #12;Quark Summary mesons and baryons

470

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 Extra Dimensions Strings and the Strong Force Thursday, May 7, 2009 #12;Scattering Summary the best way to study

471

From Quantum Mechanics to String Theory  

E-print Network

From Quantum Mechanics to String Theory Relativity (why it makes sense) Quantum mechanics and the Strong Force Symmetry and Unification String Theory: a different kind of unification Extra Dimensions Strings and the Strong Force Thursday, May 7, 2009 #12;Review of Relativity The laws of physics

472

The vacuum interaction of magnetic strings  

SciTech Connect

The author investigates the interaction of two parallel magnetic strings which is due to the perturbation of the vacuum state of a scalar massive field. The Green function with one string is studied in detail and the influence of the second string is found in perturbation theory. The Casimir is expressed in terms of Bessel functions.

Bordag, M. (Karl-Marx-Univ., Leipzig (West Germany))

1991-03-01

473

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

474

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

475

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

476

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

477

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

478

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

479

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

480

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

481

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

482

Extremal black holes and elementary string states  

Microsoft Academic Search

Some of the extremal black hole solutions in string theory have the same quantum numbers as the Bogomol'nyi saturated elementary string states. We explore the possibility that these black holes can be identified to elementary string excitations. It is shown that stringy effects could correct the Bekenstein-Hawking formula for the black hole entropy in such a way that it correctly

Ashoke Sen

1996-01-01

483

(Revised August 10, 2013) Vibrating Strings  

E-print Network

on strings, and even electromagnetic waves (light, radio, TV, microwaves, etc) have similar behaviors when travels from one end to the other. The wave "bounces" back and forth. If waves are sent down a string, the composite wave no longer "travels" along the string but appears to stand still in space and oscillate

Collins, Gary S.

484

Security of quantum bit-string generation  

Microsoft Academic Search

We consider the cryptographic task of bit-string generation. This is a generalization of coin tossing in which two mistrustful parties wish to generate a string of random bits such that an honest party can be sure that the other cannot have biased the string too much. We consider a quantum protocol for this task, originally introduced in Phys. Rev. A

Jonathan Barrett; Serge Massar

2004-01-01

485

Discrete String Simulating the Musical Scale  

Microsoft Academic Search

A discrete string with fixed endpoints carrying a finite number of beads is determined by the masses of beads and the distances between them. The string possesses a set of simple eigenfrequencies corresponding to harmonic eigenmodes. In this paper, the following problem is studied: to find a discrete string carrying seven beads such that its eigenfrequencies coincide with the freqiencies

M. Yu. Mitrofanov; O. A. Tarakanov

2003-01-01

486

CONTROL ROD CALIBRATIONS FOR THE SRE WITH THORIUM-URANIUM FUEL  

Microsoft Academic Search

Shim and safety rods of the Sodium Reactor Experiment were calibrated ; for the second core loading of thoriumuranium fuel clusters. One shim rod was ; differentially calibrated by period measurements, using two different ; configurations of the other rods to permit an estimation of the shadowing effect ; between rods. The other rods were then calibrated by comparing them

R. W. Keaten; R. A. Lewis

1962-01-01

487

Mathieu moonshine and string compactifications  

NASA Astrophysics Data System (ADS)

There is a `Mathieu moonshine' relating the elliptic genus of K3 to the sporadic group M 24. Here, we give evidence that this moonshine extends to part of the web of dualities connecting heterotic strings compactified on K3 × T 2 to type IIA strings compactified on Calabi-Yau threefolds. We demonstrate that dimensions of M 24 representations govern the new supersymmetric index of the heterotic compactifications, and appear in the Gromov-Witten invariants of the dual Calabi-Yau threefolds, which are elliptic fibrations over the Hirzebruch surfaces.

Cheng, Miranda C. N.; Dong, Xi; Duncan, John F. R.; Harvey, Jeffrey A.; Kachru, Shamit; Wrase, Timm

2013-09-01

488

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

489

Review of experiments to evaluate the ability of electrical heater rods to simulate nuclear fuel rod behavior during postulated loss-of-coolant accidents in light water reactors  

SciTech Connect

Issues related to using electrical fuel rod simulators to simulate nuclear fuel rod behavior during postulated loss-of-coolant accident (LOCA) conditions in light water reactors are summarized. Experimental programs which will provide a data base for comparing electrical heater rod and nuclear fuel rod LOCA responses are reviewed.

McPherson, G D; Tolman, E L

1980-01-01

490

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

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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.