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1

Numerical modelling of longitudinal vibrations of a sucker rod string  

NASA Astrophysics Data System (ADS)

A new technique for analyzing the dynamic behavior of a sucker rod string used in the oil well industry is presented. The main difficulty in the numerical calculation of the examined structure is a multivalued velocity—force relation determined by Coulomb's friction and by loads generated during operation of pump valves. Both the monotonic and nonmonotonic velocity—force relations are considered. A quasi-variational inequality formulation of the problem is proposed. The solution of the inequality amounts to finding the minimum of a convex nonsmooth functional at each time step by means of the Newmark difference time scheme, successive iterations and finite element discretization. The problem of functional minimization is reduced to construction of a sequence of smooth nonlinear programming problems by introducing the auxiliary variables and applying the augmented Lagrangian method. The proposed approach is used to study the longitudinal vibrations of sucker rod strings under near-real conditions. In such systems the most commonly occurring vibration modes are the stick-slip vibrations and the vibrations with natural force excited twice a cycle. The nonmonotonic character of the friction law leads to intensification of these vibrations. In the case of nonmonotonic friction law the stick-slip vibrations can occur even under the action of constant external forces.

Shardakov, I. N.; Wasserman, I. N.

2010-03-01

2

A progressive method of aluminiznig tubing strings and sucker rods  

Microsoft Academic Search

One of the rational means of preventing wear and failures, reducing the consumption of tubing and sucker rods, and, consequently, increasing their operating life and reducing the interrepair period of well operation is the use of new methods and progressive materials and protective coatings in production and repair of rubbing pairs. Starting with the 70's the All-Union Scientific-Research and Design

F. G. Mamedov; N. G. Samedova; G. G. Akhadov; E. Yu. Makarov

1992-01-01

3

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

4

Gas Interference in Sucker Rod Pump  

NASA Astrophysics Data System (ADS)

Commonly used artificial lift or dewatering system is sucker rod pump and gas interference of the pump is the biggest issue in the oil and gas industry. Gas lock or fluid pound problems occur due to the gas interference when the pump has partially or completely unfilled plunger barrel. There are several techniques available in the form of patents to solve these problems but those techniques have positive as well as negative aspects. Some of the designs rely on the leakage and some of the designs rely on the mechanical arrangements etc to break the gas lock. The present article compares the existing gas interference handling techniques.

Samad, Abdus

2010-10-01

5

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

6

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

E-print Network

AN IMPROVED FINITE DIFFERENCE CALCULATION OF DOWNHOLE DYNAMOMETER CARDS FOR SUCKER ROD PUMPS A Thesis by THOMAS AARON EVERITT Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 1987 Maj or Subj ect: Petroleum Engineering AN IMPROVED FINITE DIFFERENCE CALCULATION OF DOWNHOLE DYNAMOMETER CARDS FOR SUCKER ROD PUMPS A Thesis by THOMAS AARON EVERITT Approved as to style and content by: James W. nin...

Everitt, Thomas Aaron

1987-01-01

7

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

E-print Network

POWER REDUCTION BY BALANCING SUCKER ROD PUMPING UNIT WITH WEIGHT INDUCED PHASE ANGLE A Thesis by ERNEST ALAN NOACK Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1991 Major Subject: petroleum Engineering POWER REDUCTION BY BALANCING SUCKER ROD PUMPING UNIT WITH WEIGHT INDUCED PHASE ANGLE A Thesis by Ernest Alan Noack Approved as to style and content by; James E, Russell (Co...

Noack, Ernest Alan

1991-01-01

8

Selection of metallic materials for sucker rod pumps for hydrogen sulfide environment  

Microsoft Academic Search

This report presents general recommendations of metallic materials for the construction of sucker rod pumps for service in a hydrogen sulfide environment. Only pumps with one-piece barrels and metal plungers are considered.The recommended materials are presented in tabular form and in preferred order of listing for 9 different environments with varying degrees of abrasion and hydrogen sulfide corrosion. The materials

1973-01-01

9

Improving the reliability of guiding mechanisms in valves of sucker-rod well pumps  

Microsoft Academic Search

This article reports on research conducted at the Azerbaijan Scientific-Research and Projects Institute for Petroleum to develop new types of valve-guiding mechanisms for sucker-rod well pumps which have high resistance to hydroabrasive and corrosive\\/mechanical wear and the required strength for the given load conditions. A new type of ball valve with an elastic guiding mechanism was developed for NSV1-32 and

V. I. Sotnik; I. S. Stepanova; É. M. Rustamov

1984-01-01

10

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

E-print Network

an oil pump dynagraph. This was a new wav to analvze the subsur- face pump performance using down-hole information. Later, Gibbs and Neely s developed a model that allowed the surface measurements at the polished rod to be used to generate the downhole... to the unit that act on the pumping system. The pattern recognition technique using only downhole dynamometer cards for pump diagnosis can thus be used on any kind and size of sucker rod pumped well. Similar to a properly working pump, an improperly working...

Houang, Anne-Benedicte

1992-01-01

11

An investigation of analytical and numerical sucker rod pumping mathematical models  

E-print Network

of a prime mover and a four-bar linkage pumping unit. The pumping unit transforms the rotating energy provided by the prime mover into oscillatory polished rod motion. The rod string section consists Pumping Unit Gearbox Prime Mover Polished Rod... polished rod conditions using pump data as input. 4. Program both models so that they can be implemented on a personal computer. 5. Compare the assumptions and limitations of each model using simulated and field dynamometer card input data. 6. Develop...

Schafer, Donald Joseph

1987-01-01

12

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

2014-09-30

13

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

E-print Network

Knowledge Derived from the Expert 19 RULE DEVELOPMENT 34 Gas Interference 34 Gas Lock 40 Fluid Pound Seized Pump 44 48 Unanchored Tubing 51 TABLE OF CONTENTS (continued) Parted Rods Leaking Traveling Valve and/or Plunger Page 53 55 Leaking... Standing Valve 67 Leaking Tubing 67 SYSTEM OVERVIEW 71 SYSTEM ARCHITECTURE 74 Design Objectives Hardware Requirements Software Requirements Data Requirements 74 74 74 75 Visual Data 75 Quantitative Data 79 Data Analysis Programs API 80 80...

Derek, Henryk Jozef

1988-01-01

14

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.

2012-07-28

15

Oil well sucker rod coupling assembly  

SciTech Connect

A coupling assembly for connecting and centralizing a pair of elongate threaded-end members is described comprising: a pair of steel box couplings; a steel shaft connected to and extending between the couplings. The shaft having a tubular cylindrical sleeve of resilient abrasion-resistant non-metallic material bonded thereto and covering its surface between the couplings to form an integral unit therewith. Each such coupling having a ring of resilient abrasion-resistant non-metallic material bonded to and substantially fully covering the coupling's end face which is adjacent to the shaft; and a tubular externally fluted centralizer body mounted on the shaft and encircling the latter. The centralizer body extending radially outwardly beyond the longitudinal surfaces of the couplings. The centralizer body being formed of resilient abrasion-resistant non-metallic material.

Klyne, A.A.

1988-07-19

16

Rod guide/paraffin scraper  

SciTech Connect

This patent describes improvement in a rod guide and paraffin scraper. It comprises: a body including longitudinal ribs spaced radially and extending out from the body; having two identical halves with the body surrounding a bore to accept a sucker rod, and each of the identical halves having a locking and tightening feature using a tongue and groove concept for interfitting the halves together over the sucker rod. This improvement comprises a rod guide and paraffin scraper with two identical halves comprising; a cylindrical central body including, at each end, three longitudinal ribs radially spaced to form a triad leaving three flow channels, at each end of the body, of essentially the same size and spacing as the ribs; and an angular wedge with opposingly ramped sides at the inside end of each of the ribs for scraping and directing material into the flow channels; and a set of triangular shaped tongues that interfit with a set of triangular shaped grooves for tightening the identical halves together and over the sucker rod; and a pair of cone-shaped male locks at one end of the identical half to mate with a pair of cone-shaped female locks at the opposite end of the other identical half.

Mabry, J.F.

1991-02-26

17

A Dynamic Investigation of Sucker-Rod Pumping  

E-print Network

^ ( - 1 . 0"^U N E W (1) + U N E W » 2 . # U N E W ( KL-L) + . 5 * U N E W < N - 2 ) ) 1 4 7 . . T.-n'J'..) = C w •:! - HIR _.. _ _ . 1 ?5 3 P D M A U \\' E W ( M... ) / ? ; NM1 5 N - 1 M P S * 0 K O U N T = 0 P R I N T 2 , R S T H , W B . W F , W R 0 D , Q E L X , D E L T 2 F O R M A T T 6 H R S T M = , F 7 . 4 , 5 H W 8 = , E 1 1 . 4 , 5 H W F A . E L L . 4 , 7 H W R O D = , E L L . 4 ," 1 7 H D J 1 X = , E L L . 4...

Knapp, Roy M.

1969-01-01

18

Fluid inertia consideration in sucker rod pump diagnosis  

E-print Network

artificial lift in the U.S.A. It has been reported numerous times in the literature to exceed 85% of non-flowing well's lift systems. The efficient maintenance and operation of these wells is essential for them to remain profitable and productive...

Csaszar, Albert Bela

1993-01-01

19

Rangewide molecular structuring in the Utah sucker ( Catostomus ardens )  

Microsoft Academic Search

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

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

2006-01-01

20

A wall climbing robot with simple suckers  

Microsoft Academic Search

A new type of wall climbing robot to clean window is proposed in this paper. The developed robot can climb the vertical pane by rotating a crawler that has general purpose suckers. The robot can climb more simply and safely than other methods because it uses a simple mechanism. As the result of the experiments, it is confirmed that the

Nobuhiro Okada; Kyohei Yamanaka; Eiji Kondo

2009-01-01

21

Hand-held computer designs rod pumping installation  

Microsoft Academic Search

This article describes the program designed to facilitate the design of sucker rod pumping systems for conventional and Mark 2 units. For depths of 2000' or less the modified Mill's method is used, and below 2000' the design procedures of API RP llL are incorporated. The program automatically uses the appropriate design procedure depending on the fluid or pump level.

Herlihy

1984-01-01

22

FACTORS INFLUENCING GROWTH AND SURVIVAL OF WHITE SUCKER, CATOSTOMUS COMMERSONI  

EPA Science Inventory

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

23

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

Microsoft Academic Search

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

William J. Hauser

1969-01-01

24

Bioenergetics and Population Dynamics of Flannelmouth Sucker and Bluehead Sucker in Grand Canyon as Evidenced by Tag Recapture Observations  

Microsoft Academic Search

Flannelmouth suckers Catostomus latipinnus and bluehead suckers C. discolobus in the Grand Canyon of the Colorado River are among the few native species to persist after river conditions changed with the completion of Glen Canyon Dam in 1963. To evaluate the effectiveness of adaptive management manipulations to the system for recovering native species, it is necessary to estimate basic demographic

Carl J. Walters; Brett T. van Poorten; Lewis G. Coggins

2012-01-01

25

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

Microsoft Academic Search

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

Molly O. Ahlgren

1996-01-01

26

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

Microsoft Academic Search

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

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

2008-01-01

27

Rangewide molecular structuring in the Utah sucker (Catostomus ardens).  

PubMed

The Utah sucker (Catostomus ardens) is endemic to the Bonneville Basin and the upper Snake River drainage in western North America, and is thought to hybridize with the federally endangered June sucker (Chasmistes liorus mictus) in Utah Lake (Bonneville Basin). Here we describe the discovery of a major subdivision in Utah suckers (4.5% mitochondrial sequence divergence) between the ancient Snake River drainage and the Bonneville Basin. This boundary has not previously been recognized in Utah suckers based on morphologic variation, but has been recently described in two endemic cyprinids in the region. Populations in valleys east of the Wasatch Mountains in Utah clustered with the Snake River populations, suggesting that these valleys may have had an ancient hydrologic connection to the Snake River. We also found evidence of population isolation within the Bonneville Basin, corresponding to two Pleistocene sub-basins of the ancient Lake Bonneville. In contrast, we found no molecular evidence for deep divergence between Utah suckers and June suckers in Utah Lake or for a history of hybridization between divergent lineages in that population, although we recognize that demographic events may have obscured this signal. These findings suggest that the morphological differences between Utah and June suckers in Utah Lake may be the result of strong, and relatively recent, ecological selection. In summary, morphological and molecular characters seem to vary along different axes in different portions of the range of this taxon, providing an interesting system for studying the contributions of neutral and adaptive variation to species diversity. PMID:16780436

Mock, K E; Evans, R P; Crawford, M; Cardall, B L; Janecke, S U; Miller, M P

2006-07-01

28

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

29

An analysis of sucker regeneration of trembling aspen  

Microsoft Academic Search

Aspen (Populus tremuloides Michx.) is a clonal tree species that commonly regenerates via root suckering after disturbance. This paper reviews the literature and identifies critical gaps in our understanding of the dynamics of aspen root suckering. The role of plant growth regulators (e.g., hormones, carbohydrates), environmental conditions (e.g., soil moisture, temperature, nutrient availability), overstory disturbance (e.g., harvesting, wildfire), ground distur

Brent R. Frey; Victor J. Lieffers; Simon M. Landhäusser; Phil G. Comeau; Ken J. Greenway

2003-01-01

30

Structure and mechanical properties of Octopus vulgaris suckers.  

PubMed

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

2014-02-01

31

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

32

Habitat features affect bluehead sucker, flannelmouth sucker, and roundtail chub across a headwater tributary system in the Colorado River Basin  

USGS Publications Warehouse

We assessed the distributions of three species of conservation concern, bluehead sucker (Catostomus discobolus), flannelmouth sucker (Catostomus latipinnis), and roundtail chub (Gila robusta), relative to habitat features across a headwater tributary system of the Colorado River basin in Wyoming. We studied the upper Muddy Creek watershed, Carbon County, portions of which experience intermittent flows during late summer and early fall. Fish and habitat were sampled from 57 randomly-selected, 200-m reaches and 416 habitat units (i.e., pools, glides, or runs) during the summer and fall of 2003 and 2004. Among reaches, the occurrences of adults and juveniles of all three species were positively related to mean wetted width and the surface area of pool habitat, and the occurrences of adult bluehead sucker and roundtail chub were also positively related to the abundance of rock substrate. Only juvenile bluehead sucker appeared to be negatively influenced by the proportion of a reach that was dry at the time of sampling. Within individual pools, glides, and runs, the occurrences of adults and juveniles of all three species were positively related to surface area and maximum depth, and occurrences of bluehead sucker and flannelmouth sucker juveniles were more probable in pools than in glides or runs.

Bower, M.R.; Hubert, W.A.; Rahel, F.J.

2008-01-01

33

The Morphology and Adhesion Mechanism of Octopus vulgaris Suckers  

PubMed Central

The octopus sucker represents a fascinating natural system performing adhesion on different terrains and substrates. Octopuses use suckers to anchor the body to the substrate or to grasp, investigate and manipulate objects, just to mention a few of their functions. Our study focuses on the morphology and adhesion mechanism of suckers in Octopus vulgaris. We use three different techniques (MRI, ultrasonography, and histology) and a 3D reconstruction approach to contribute knowledge on both morphology and functionality of the sucker structure in O. vulgaris. The results of our investigation are two-fold. First, we observe some morphological differences with respect to the octopus species previously studied (i.e., Octopus joubini, Octopus maya, Octopus bimaculoides/bimaculatus and Eledone cirrosa). In particular, in O. vulgaris the acetabular chamber, that is a hollow spherical cavity in other octopuses, shows an ellipsoidal cavity which roof has an important protuberance with surface roughness. Second, based on our findings, we propose a hypothesis on the sucker adhesion mechanism in O. vulgaris. We hypothesize that the process of continuous adhesion is achieved by sealing the orifice between acetabulum and infundibulum portions via the acetabular protuberance. We suggest this to take place while the infundibular part achieves a completely flat shape; and, by sustaining adhesion through preservation of sucker configuration. In vivo ultrasonographic recordings support our proposed adhesion model by showing the sucker in action. Such an underlying physical mechanism offers innovative potential cues for developing bioinspired artificial adhesion systems. Furthermore, we think that it could possibly represent a useful approach in order to investigate any potential difference in the ecology and in the performance of adhesion by different species. PMID:23750233

Tramacere, Francesca; Beccai, Lucia; Kuba, Michael; Gozzi, Alessandro; Bifone, Angelo; Mazzolai, Barbara

2013-01-01

34

The morphology and adhesion mechanism of Octopus vulgaris suckers.  

PubMed

The octopus sucker represents a fascinating natural system performing adhesion on different terrains and substrates. Octopuses use suckers to anchor the body to the substrate or to grasp, investigate and manipulate objects, just to mention a few of their functions. Our study focuses on the morphology and adhesion mechanism of suckers in Octopus vulgaris. We use three different techniques (MRI, ultrasonography, and histology) and a 3D reconstruction approach to contribute knowledge on both morphology and functionality of the sucker structure in O. vulgaris. The results of our investigation are two-fold. First, we observe some morphological differences with respect to the octopus species previously studied (i.e., Octopus joubini, Octopus maya, Octopus bimaculoides/bimaculatus and Eledone cirrosa). In particular, in O. vulgaris the acetabular chamber, that is a hollow spherical cavity in other octopuses, shows an ellipsoidal cavity which roof has an important protuberance with surface roughness. Second, based on our findings, we propose a hypothesis on the sucker adhesion mechanism in O. vulgaris. We hypothesize that the process of continuous adhesion is achieved by sealing the orifice between acetabulum and infundibulum portions via the acetabular protuberance. We suggest this to take place while the infundibular part achieves a completely flat shape; and, by sustaining adhesion through preservation of sucker configuration. In vivo ultrasonographic recordings support our proposed adhesion model by showing the sucker in action. Such an underlying physical mechanism offers innovative potential cues for developing bioinspired artificial adhesion systems. Furthermore, we think that it could possibly represent a useful approach in order to investigate any potential difference in the ecology and in the performance of adhesion by different species. PMID:23750233

Tramacere, Francesca; Beccai, Lucia; Kuba, Michael; Gozzi, Alessandro; Bifone, Angelo; Mazzolai, Barbara

2013-01-01

35

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

36

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

E-print Network

sucker abundances resulted in these species being listed as endangered under the U.S. Endangered Species species. Continued protection of endangered shortnose suckers requires the protection of Klamath catostomids, or suckers, are currently listed as threatened or endangered under the U.S. Endangered Species

May, Bernie

37

Commentary: selenium study on endangered razorback sucker is flawed  

Microsoft Academic Search

The razorback sucker (Xyrauchen texanus) is listed as federally endangered throughout its range. A massive recovery effort by the Recovery Implementation Program for Endangered Fish Species in the Upper Colorado River Basin has focused its efforts in the upper Colorado River. The upper Colorado River basin also has two locations that have been identified by the National Irrigation Water Quality

Steven J. Hamilton

2005-01-01

38

Commentary: selenium study on endangered razorback sucker is flawed.  

PubMed

The razorback sucker (Xyrauchen texanus) is listed as federally endangered throughout its range. A massive recovery effort by the Recovery Implementation Program for Endangered Fish Species in the Upper Colorado River Basin has focused its efforts in the upper Colorado River. The upper Colorado River basin also has two locations that have been identified by the National Irrigation Water Quality Program as having substantial selenium contamination. Selenium is toxic to fishes, affecting reproductive success. Thus, there is concern about potential effects of selenium on the endangered razorback sucker. Two sets of studies have investigated the effects of selenium on razorback suckers, but study results are conflicting. This commentary evaluates studies that claim selenium is not a problem for razorback sucker. We find that study bias was so pervasive that purported conclusions were unwarranted. Contaminated control water, older life stages of fish tested, lack of methodology for analysis of selenium in water, diet, or fish, use of rotifer food, low feeding rates, low growth rates of fish, and improper storage of site waters resulted in an apparent erroneous linkage of high selenium in whole-body residues with no adverse effects. PMID:15922797

Hamilton, Steven J

2005-07-01

39

Observations on the Longnose Sucker in Yellowstone Lake  

Microsoft Academic Search

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

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

1954-01-01

40

Control rods  

SciTech Connect

A control rod to be arranged in a nuclear reactor core comprises a body of a control rod, control guide rollers, pins connected to the guide rollers, and fixing members directly welded to the body of the control rod. The pins slidably support the respective guide rollers and the fixing members are engaged with the pins with a small clearance therebetween so as not to transfer welding heat from the fixing member to the pin.

Aisaka, T.; Hasegawa, S.; Kawai, M.; Nawai, T.

1983-08-23

41

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.

2011-10-11

42

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

43

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

Microsoft Academic Search

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

Megan V. McPhee; Thomas F. Turner

2004-01-01

44

VIBRATIONS OF STRINGS WITH ARBITRARY LARGE DISPLACEMENTS  

Microsoft Academic Search

ABSTRACT The paper considers arbitrary large deflections of strings and connected with it coupling of vertical and horizontal displacements. Strings are made of a linearly elastic material. The physical model of a tie rod, equations and algorithm of their solutions as well as examples of string analysis are presented. Obtained results are compared to analytical solutions already known but for

Adam Grabowski

45

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

46

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 ...

47

BIOLOGY AND OCCURRENCE OF THE LEECH, ACTINOBDELLA INEQUIANNULATA (ANNELIDA: HIRUDINEA: GLOSSIPHONIIDAE) PARASITIC ON TWO SPECIES OF SUCKERS  

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. This study established the presence of only one species of leech, Actinobdela inequ...

48

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

49

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

E-print Network

was coded on a personal computer using FORTRAN77. The model generates results quite efficiently, taking less than 20 seconds to complete one run in most of the cases studied. The differences in execution times between the proposed model and a comparable... unknown parameters. In fact, we can explicitly calculate the polished-zod load by using the equation from the fizsr row. The equation is P Az B c h PRL E A (Bu/Bx) = (Ul - Up) - (2Utp + Utl) x=p 144 gc h gc h g h ) (2Uttp - Uttl) + 6 2 2...

Garcia, Julian Perez

1988-01-01

50

Selenium impacts on razorback sucker, Colorado: Colorado River  

Microsoft Academic Search

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,

Steven J. Hamilton; Kathy M. Holley; Kevin J. Buhl; Fern A. Bullard

2005-01-01

51

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

Microsoft Academic Search

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

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

2003-01-01

52

Suckers and other bursal structures of Pomphorhynchus bulbocolli and Acanthocephalus dirus (Acanthocephala).  

PubMed

Accessory copulatory structures in the bursa of Pomphorhynchus bulbocolli include 2 suckers on the inner surface and bursal rays. A stylet was present in the penis of this species. Two suckers were present in the bursa of Acanthocephalus dirus, but bursal rays and a stylet in the penis were not observed. This is the first report of suckers present in the bursas of acanthocephalans. Copulatory cement caps and holes surrounded by a ring approximating the inner bursal diameter and not covered by a cap were present on the sides of some P. bulbocolli, indicating the possibility of hypodermic insemination in this species. PMID:2040955

Doyle, L R; Gleason, L N

1991-06-01

53

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

54

Development of a small sucker manipulator for underwater surgery support.  

PubMed

WaFLES (Water-Filled LaparoEndoscopic Surgery) is an operative method suggested by Igarashi et al., which has several advantages, such as, preventing the drying of inner organs, and being able to use ultrasound devices for real time monitoring. However, grasping of inner organs with usual forceps for move and incision purpose is difficult. Therefore our ultimate goal is to develop a small sucker manipulator for WaFLES support. Experiments were conducted to explore suitable suction cups for underwater application, and suitable structure (cup-to-cup distance, elasticity of binding material, layouts of multiple cups) for a multiple-cup assembly, in terms of adsorption force and tolerance to sideslip. Experiment results showed that 1) the shape of each single suction cup for the underwater application was identified; 2) the structure of the multiple-cup assembly affects the adsorption force and tolerance to sideslip. PMID:25569977

Tsuchiya, Nobuto; Sekine, Masashi; Kita, Kahori; Yu, Wenwei

2014-01-01

55

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

E-print Network

(Catostomus commersoni) sampled along a gradient of temperature and agrichemicals in the Oldman River, Alberta of the Mountain Whitefish, (Prosopium williamsoni, a cold-water fish) and White Sucker (Catostomus commersoni

Hontela, Alice

56

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

SciTech Connect

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

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

1993-05-01

57

75 FR 38441 - Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for Santa Ana Sucker  

Federal Register 2010, 2011, 2012, 2013, 2014

...minimizes and mitigates the effects of expected habitat loss and associated incidental take of covered...assess threats to the sucker from degraded habitat (such as reduced water quality, loss of habitat, presence of nonnative predators and...

2010-07-02

58

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...

59

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

60

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

Microsoft Academic Search

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

Philippe Brodeur; Pierre Magnan; Michel Legault

2001-01-01

61

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

62

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

63

String Vibrations  

NSDL National Science Digital Library

This site, by Andrew Davidhazy at the Rochester Institute of Technology, describes how to make interesting and artistic photographs of a vibrating string. Davidhazy explains how the string is vibrated, how the string is lit, and even the exposure time and the effect it has on the resulting image. Four images of the vibrating string are included.

Davidhazy, Andrew

64

Overview of Endangered Suckers in the Klamath Basin: Does it Take One to Know One?  

NASA Astrophysics Data System (ADS)

Severe water quality problems in the Klamath Basin of Oregon and California have led to critical fisheries concerns for the region. In the Upper Klamath Basin, two fish species, the Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris) were listed as federally endangered in 1988. These species are large, long-lived, lake-dwelling fishes endemic to the Upper Klamath Basin. Declining population trends for both species were noted as early as the mid 1960's, however, the severity of these declines were not evident until the mid 1980's. At the time of listing, population structures were dominated by older individuals with little evidence of recent significant recruitment into adult populations. In the early 1990s there was evidence of recruitment for Lost River suckers. Successive years of large fish kills in Upper Klamath Lake from 1995 to 1997, however, substantially reduced adult populations of both Lost River and shortnose suckers. Additionally, the 1995 and 1996 fish kills appeared to have been selective for larger-sized individuals and would have disproportionately affected females and resulted in an overall lower reproductive potential. Water quality and physical habitat limitations are considered to be the most limiting factors to species recovery. Life history patterns of Lost River and shortnose suckers in Upper Klamath Lake have been severely disrupted by recurrent periods of poor water quality that appear to be the root cause of fish kills and likely negatively influence the production of juvenile suckers. Habitat degradation around Upper Klamath Lake and in its tributaries likely contributes to water quality problems and also limits the physical habitat needed for successful adult sucker spawning as well as larval and juvenile rearing. Ultimately, a better understanding of the factors that influence water quality in Upper Klamath Lake as well as developing a sound strategy for habitat restoration is needed to promote recovery of these species. Future challenges fisheries biologists in the Klamath Basin face include developing a better understanding of sucker population dynamics and habitat requirements at different life stages. One of the largest challenges, however, will be the integration of biological information on suckers with an improved understanding of water quality and physical habitat processes.

Shively, R. S.; Vanderkooi, S.

2005-12-01

65

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,

66

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

67

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

68

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

Microsoft Academic Search

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

Pascale Lafontaine; Julian J. Dodson

1997-01-01

69

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

70

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

E-print Network

Spatial structuring of length-at-age of the benthivorous white sucker (Catostomus commersoni sucker, Catostomus commersoni, in 32 Ontario lakes. The spatial structuring of these data was examined structuring / Mantel test / distance matrix / Catostomus commersoni / Ontario lakes / Canada Résumé

Chen, Yong

71

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

72

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

73

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

Microsoft Academic Search

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

Peter D. Premdas; Chris D. Metcalfe

1994-01-01

74

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

Microsoft Academic Search

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

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

1995-01-01

75

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

Microsoft Academic Search

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

Donald M. Baltz; Peter B. Moyle

1984-01-01

76

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

77

Factors affecting condition of flannelmouth suckers in the Colorado River, Grand Canyon, Arizona  

USGS Publications Warehouse

The impoundment of the Colorado River by Glen Canyon Dam, Arizona, in 1963 created a highly regulated environment in the Grand Canyon that altered the native fish populations, including the flannelmouth sucker Catostomus latipinnis. Flannelmouth suckers were sampled from 1991 to 2001 to determine seasonal, annual, and spatial trends in fish condition (i.e., relative weight [Wr]). Mean Wr peaked during the prespawn and spawning periods and was lowest in summer and fall, but it was never lower than 93. Condition was variable throughout the Grand Canyon but was typically greatest at intermediate distances from Glen Canyon Dam, possibly because of the increased number of warmwater tributaries in this reach. Flannelmouth sucker condition in September was positively correlated with Glen Canyon Dam discharge during summer (June-August); this result may be due to the larger euphotic zone and greater macroinvertebrate abundance observed during higher water flows. Increased dam discharge that stimulates river productivity may provide benefits for this native fish.

Paukert, C.; Rogers, R.S.

2004-01-01

78

Phonons in lattices with rod-like particles  

Microsoft Academic Search

The paper studies the modes of vibrations of a lattice with rod-like particles, in a continuum model where the sites of the lattice are the connections among strings and rigid rods. In these structures then, translational and rotational degrees of freedom are strongly coupled. We will discuss in particular two-dimensional lattices with auxetic-like behaviour. Auxetics are materials with a negative

A. Sparavigna

2007-01-01

79

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

80

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

81

String Theory  

NASA Astrophysics Data System (ADS)

After reviewing the original motivation for the formulation of string theory and what we learned from it, I discuss some of the implications of the holographic principle and of string dualities for the question of the building blocks of nature.

Susskind, Leonard

2013-01-01

82

String Phenomenology  

Microsoft Academic Search

In this dissertation we explore two different ways of determining string models for low-energy phenomenology, the string dynamical determination and the low-energy measurement specification. We will show that both of these approaches are required to relate the string theories to low-energy phenomena. We begin with a review of different formulations of the free and interactive string theories. We show the

Rulin Xiu

1994-01-01

83

Piston rod seal  

SciTech Connect

In a piston rod seal of the type comprising a gland through which the piston rod is passed the piston is provided with a sleeve surrounding the piston rod and extending axially so as to axially partly overlap the gland when the piston is in its bottom dead center position.

Lindskoug, Stefan (Malmo, SE)

1984-01-01

84

Hammered Strings  

NASA Astrophysics Data System (ADS)

In the next three chapters we consider the science of hammered string instruments. In this chapter, we present a brief discussion of vibrating strings excited by a hard or soft hammer. Chapter 20 discusses the most important hammered string instrument, the piano - probably the most versatile and popular of all musical instruments. Chapter 21 discusses hammered dulcimers, especially the American folk dulcimer.

Rossing, Thomas D.

85

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

Microsoft Academic Search

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

John H. C. Pippy; Gerard M. Hare

1969-01-01

86

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

Microsoft Academic Search

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

Martin Kavaliers

1982-01-01

87

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

Microsoft Academic Search

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

James F. McElman; Eugene K. Balon

1980-01-01

88

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

89

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

EPA Science Inventory

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

90

Selenium in eggs and milt of razorback sucker ( Xyrauchen texanus ) in the middle Green River, Utah  

Microsoft Academic Search

Eggs from three female and milt from five male endangered razorback suckers (Xyrauchen texanus) were collected from the Razorback Bar (about 20 km upstream of Ashley Creek) in the Green River of northeastern Utah. Eggs, but not milt, had concentrations of selenium that were above the range of selenium concentrations in control fish from laboratory studies or reference fish from

S. J. Hamilton; B. Waddell

1994-01-01

91

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

92

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

93

Life history of the bridgelip sucker in the central Columbia River  

SciTech Connect

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

Dauble, D.D.

1980-01-01

94

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

EPA Science Inventory

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

95

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

Microsoft Academic Search

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

Richard E. Siefert

1972-01-01

96

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

Microsoft Academic Search

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

Tom B. Kennedy; Gary L. Vinyard

1997-01-01

97

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

98

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

99

79 FR 69880 - Endangered and Threatened Wildlife and Plants; Draft Recovery Plan for the Santa Ana Sucker...  

Federal Register 2010, 2011, 2012, 2013, 2014

...short-lived member of the sucker family of fishes (Catostomidae), named so primarily because of the downward orientation and anatomy of its mouth parts, which allow it to consume algae, small invertebrates, and other organic matter with its fleshy,...

2014-11-24

100

Assessment of Population Status for a White Sucker ( Catostomus commersoni ) Population Exposed to Bleached Kraft Pulp Mill Effluent  

EPA Science Inventory

A predictive model was developed to translate changes in the fecundity and the age structure of a breeding population of white sucker ( Catostomus commersoni ) collected in the field to alterations in population growth rate. Application of this density dependent population ...

101

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

Federal Register 2010, 2011, 2012, 2013, 2014

...will be obtained from Forest Service-managed land within or near...or from commercial sources. Trees are expected to come from Forest Service-managed lands within the Sucker...fisheries biologist will identify trees for the project....

2010-02-02

102

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

Microsoft Academic Search

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

David A. Bell; Mary Beverley-Burton

1980-01-01

103

Pull rod assembly  

DOEpatents

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

Cioletti, Olisse C. (Pittsburgh, PA)

1990-01-01

104

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

105

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

Microsoft Academic Search

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

Lloyd C. Mohr; Sandra M. Chalanchuk

1985-01-01

106

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

107

Cosmological Quantum String Vacua and String-String Duality  

E-print Network

Implications of string-string dualities to cosmological string vacua are discussed. Cosmological vacua of classical string theories comprise of disjoint classses mapped one another by scale-factor T-duality. Each classes are, however, afflicted with initial/final cosmological singularities. It is argued that quantum string theories and string-string dualities dramatically resolve these cosmological singularities out so that disjoint classical cosmological vacua are continuously connected in a unified manner. A natural inflationary cosmology follows from this.

Rey, S J

1996-01-01

108

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

109

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

110

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

USGS Publications Warehouse

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

Bailey, Merryll M.

1969-01-01

111

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

Microsoft Academic Search

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

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

1984-01-01

112

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

113

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

114

Physiological stress response in white suckers from agricultural drain waters containing pesticides and selenium  

Microsoft Academic Search

To assess the effect of agriculture drain water, a complex mixture containing pesticides and selenium (Se), on the physiological stress response, white suckers were collected from irrigation return flows in the summer and the fall and subjected to a stress challenge. Water (0.40–26.71?g\\/L) and muscle Se (0.37–1.52?g\\/g ww) levels were elevated at two sites and plasma acetylcholinesterase (AChE) activity (a

L. L. Miller; J. B. Rasmussen; V. P. Palace; A. Hontela

2009-01-01

115

Sublethal effects of aged oil sands-affected water on white sucker (Catostomus commersonii).  

PubMed

To investigate impacts of proposed oil sands aquatic reclamation techniques on benthic fish, white sucker (Catostomus commersonii Lacépède, 1803) were stocked in 2 experimental ponds-Demonstration Pond, containing aged fine tailings capped with fresh water, consistent with proposed end-pit lake designs, and South Bison Pond, containing aged unextracted oil sands material-to examine the effects of unmodified hydrocarbons. White sucker were stocked from a nearby reservoir at both sites in May 2010 and sampled 4 mo later to measure indicators of energy storage and utilization. Comparisons were then made with the source population and 2 reference lakes in the region. After exposure to aged tailings, white sucker had smaller testes and ovaries and reduced growth compared with the source population. Fish introduced to aged unextracted oil sands material showed an increase in growth over the same period. Limited available energy, endocrine disruption, and chronic stress likely contributed to the effects observed, corresponding to elevated concentrations of naphthenic acids, aromatic compounds in bile, and increased CYP1A activity. Because of the chemical and biological complexity of these systems, direct cause-effect relationships could not be identified; however, effects were associated with naphthenic acids, polycyclic aromatic hydrocarbons, ammonia, and high pH. Impacts on growth have not been previously observed in pelagic fishes examined in these systems, and may be related to differences in sediment interaction. Environ Toxicol Chem 2015;34:589-599. © 2014 SETAC. PMID:25545538

Arens, Collin J; Hogan, Natacha S; Kavanagh, Richard J; Mercer, Angella G; Kraak, Glen J Van Der; van den Heuvel, Michael R

2015-03-01

116

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

117

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

NASA Astrophysics Data System (ADS)

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

McIvor, Carole C.; Thieme, Michele L.

118

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

USGS Publications Warehouse

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

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

2014-01-01

119

[Genetic structure of the Siberian Sucker (Catostomus catostomus rostratus) according to data on sequence variation of the mtDNA cytochrome B gene].  

PubMed

Data regarding the structure and variation of the nucleotide sequence of the cytochrome b gene of mitochondrial DNA of the Siberian Sucker from the Kolyma River were obtained. Analysis of the median network revealed that evolutionary lines diverged from a common ancestor. Penetration of the sucker into Asia from Northern America took place between the Early and Middle Pleistocene. Prolonged reproductive isolation of the Siberian and Northern American suckers led to interspecies divergence with the appearance of amino acid substitutions, which, apparently, fixed due to positive selection. The Siberian Sucker appeared to have three modifications of the Cytb protein. PMID:25735175

Bachevskaia, L T; Pereverzeva, V V; Ivanova, G D; Agapova, G A; Primak, A A

2014-01-01

120

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

121

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

122

Cosmic strings  

NASA Technical Reports Server (NTRS)

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

Bennett, David P.

1988-01-01

123

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

124

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

125

String Phenomenology  

Microsoft Academic Search

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

C. Muñoz; Teorica C-XI

1998-01-01

126

[Nucleotide variation in the mitochondrial DNA cytochrome oxidase 1 gene in the Siberian sucker (Catostomus catostomus rostratus) from Kolyma River].  

PubMed

This study presents the data of the first molecular genetic analysis of the Siberian sucker from Kolyma River. Polymorphism of the mtDNA cytochrome oxidase 1 gene was established. Comparative sequence analysis of the gene examined and the GenBank variants characterizing suckers from the rivers of Canada enabled the suggestion that the sucker penetrated to Asia from North America approximately at the end of Early and the beginning of the Middle Pleistocene. It was demonstrated that intrapopulation genetic variation in the Siberian sucker accounted for 11.63% of total variation, while the proportion of the intergroup, component (Fst) constituted 88.37%. It seems likely that a considerable proportion of intergroup variation was caused by the long period of isolation of the Siberian sucker in Kolyma River. The prevalence of one common haplotype, CH-COI 1, in the sample examined indicates that the founder effect played an importaht role in the history of the formation of the Kolyma population. PMID:25720253

Bachevskaja, L T; Pereverzeva, V V; Ivanova, G D; Agapova, G A

2014-10-01

127

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

128

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

Microsoft Academic Search

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

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

1998-01-01

129

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

Microsoft Academic Search

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

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

2001-01-01

130

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

Microsoft Academic Search

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

Andrea Bertolo; Pierre Magnan

2005-01-01

131

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

132

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

USGS Publications Warehouse

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

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

1954-01-01

133

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

134

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

135

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

136

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

137

String Cells  

NSDL National Science Digital Library

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

Marlys McCurdy (Idaho State University/ College of Education REV)

1995-06-30

138

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

139

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

140

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

141

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

142

Seasonal Distribution and Abundance of Larval and Juvenile Lost River and Shortnose Suckers in Hanks Marsh, Upper Klamath National Wildlife Refuge, Upper Klamath Lake, Oregon: 2007 Annual Report  

USGS Publications Warehouse

In the summer of 2007, we undertook an assessment of larval and juvenile sucker use of Hanks Marsh in Upper Klamath Lake, Oregon. This 1,200-acre marsh on the southeastern shoreline of the lake represents part of the last remaining natural emergent wetland habitat in the lake. Because of the suspected importance of this type of habitat to larval and juvenile endangered Lost River and shortnose suckers, it was thought that sucker abundance in the marsh might be comparatively greater than in other non-vegetated areas of the lake. It also was hoped that Hanks Marsh would serve as a reference site for wetland restoration projects occurring in other areas of the lake. Our study had four objectives: to (1) examine seasonal distribution and relative abundance of larval suckers in and adjacent to Hanks Marsh in relation to habitat features such as depth, vegetation, water quality, and relative abundance of non-sucker species; (2) determine the presence or absence and describe the distribution of juvenile suckers [35 to 80 mm standard length (SL)] along the periphery of Hanks Marsh; (3) assess spatial and temporal overlap between larval suckers and their potential predators; and (4) assess suitability of water quality throughout the summer for young-of-the-year suckers. Due to the low number of suckers found in the marsh and our inability to thoroughly sample all marsh habitats due to declining lake levels during the summer, we were unable to completely address these objectives in this pilot study. The results, however, do give some indication of the relative use of Hanks Marsh by sucker and non-sucker species. Through sampling of larval and juvenile suckers in various habitat types within the marsh, we determined that sucker use of Hanks Marsh may be very low in comparison with other areas of the lake. We caught only 42 larval and 19 juvenile suckers during 12 weeks of sampling throughout the marsh. Sucker catches were rare in Hanks Marsh, and were lower than catch rates in other marshes of Upper Klamath Lake and in other nearshore and offshore areas of the lake. Based on the few suckers we did capture in Hanks Marsh, larvae tended to be found more often in vegetated habitats. A modified sampling design and approach may be necessary to address the objectives in this study, given that declining lake-surface elevation prevented us from adequately sampling all portions of the marsh throughout the sampling season. Common non-sucker species in Hanks Marsh included juvenile and adult brown bullhead, larval blue chub, tui chub, fathead minnow, and yellow perch. This species composition was similar to that of other marshes in Upper Klamath Lake but most species were found in lower numbers in Hanks Marsh than other marshes. It may be that use of Hanks Marsh is limited by poor water quality, which we found to exist at many sites after June. It also may be that access to or habitat in the marsh is limited at certain times of the year by low water. Although the results from this initial study of Hanks Marsh indicate that the area may have little direct benefit for sucker species, indirect benefits for these species possibly may come from its positive influence on some aspects of water quality in the lake, such as regulation of pH. It also may be the case that use of Hanks Marsh may vary by year and conditions; however, under the current scope of the study, we were unable to investigate inter-annual variability.

Anderson, Greer O.; Wilkens, Alexander X.; Burdick, Summer M.; VanderKooi, Scott P.

2009-01-01

143

Beech regeneration of seed and root sucker origin: A comparison of morphology, growth, survival, and response to defoliation  

Microsoft Academic Search

American beech (Fagus grandifolia Ehrh.) reproduces sexually, and vegetatively by root suckers. Although many studies have investigated its regeneration response, most did not account for differences that may exist between its two modes of reproduction. This study was performed in an old-growth Acer - Fagus forest in southern Quebec, where beech bark disease had only a minor effect at the

Marilou Beaudet; Christian Messier

2008-01-01

144

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

145

STATUS OF WILD RAZORBACK SUCKER IN THE GREEN RIVER BASIN, UTAH AND COLORADO, DETERMINED FROM BASINWIDE MONITORING AND  

E-print Network

STATUS OF WILD RAZORBACK SUCKER IN THE GREEN RIVER BASIN, UTAH AND COLORADO, DETERMINED FROM BASINWIDE MONITORING AND OTHER SAMPLING PROGRAMS By K. R. Bestgen, G. B. Haines, R. Brunson, T. Chart, M) SWCA, Inc. Flagstaff, Arizona (MT) Final Report Colorado River Recovery Implementation Program Project

146

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

Microsoft Academic Search

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

Ken D. Oakes; Glen J. Van Der Kraak

2003-01-01

147

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

Microsoft Academic Search

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

Martin Kavaliers

1982-01-01

148

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

Federal Register 2010, 2011, 2012, 2013, 2014

...A relatively small, but significant, number of Lost River sucker also spawn over gravel bottoms at shoreline springs or upwellings along the margins of Upper Klamath Lake (Janney et al. 2009, pp. 8-9). Larvae spend little time in rivers or...

2013-04-16

149

Assessment of Population Status for a White Sucker ( Catostomus commersoni ) Population Exposed to Bleached Kraft Pulp Mill Effluent  

EPA Science Inventory

Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to translate changes in the fecundity and the age structure of a breeding population of white sucker (Catostomus commersoni) co...

150

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

Microsoft Academic Search

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

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

1984-01-01

151

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

Microsoft Academic Search

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

S. J. Hamilton; K. J. Buhl

1997-01-01

152

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

Microsoft Academic Search

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

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

153

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

USGS Publications Warehouse

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

Ellsworth, Craig M.; VanderKooi, Scott P.

2011-01-01

154

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

155

String Cosmology  

E-print Network

A pedagogical introduction to aspects of string cosmology, including the landscape (BPBT) solution to the cosmological constant problem, brane-antibrane inflation, warped compactification, the KKLMMT model, the eta problem of SUGRA models, DBI inflation, Kahler modulus and racetrack inflation, the D3-D7 model, cosmic superstrings, and the problem of reheating. Also includes basic methods for phenomenology of multifield models with nonstandard kinetic terms.

James M. Cline

2014-07-12

156

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

157

Spinning Rods: Experiment & Theory  

NASA Astrophysics Data System (ADS)

Mixing and transport properties of the fluid motion induced by a slender rod attached to a plane sweeping out a cone are examined in a table- top experiment. This experiment is used to validate an exact solution for the motion of a spheroid sweeping out a double cone in free space and an asymptotic solution for a slender body attached to a plane. Validation of the theory is used to examine mixing and transport of the same experiment on the microscale.

Toledo, Jonathan; McLaughlin, Richard M.; Camassa, Roberto; Leiterman, Terry Jo; Superfine, Richard; Hao, Jing; Vicci, Leandra; Brooks, Adam

2006-03-01

158

Gravitational field of vacuum domain walls and strings  

Microsoft Academic Search

The gravitational properties of vacuum domain walls and strings are studied in the linear approximation of general relativity. These properties are shown to be very different from those of regular massive planes and rods. It is argued that the domain walls are gravitationally unstable and collapse at a certain time approx.t\\/sub c\\/ after their creation. If the vacuum walls ever

Alexander Vilenkin

1981-01-01

159

SUPERTRACES IN STRING THEORY  

E-print Network

We demonstrate that the spectrum of any consistent string theory in $D$ dimensions must satisfy a number of supertrace constraints: $ Str~M^{2n}=0 $ for $0 \\leq n string theories, including critical heterotic strings. For strings lacking spacetime supersymmetry, these supertrace constraints will be satisfied as a consequence of a hidden ``misaligned supersymmetry'' in the string spectrum. [Talk given by R.C.M. at Strings '95; to appear in Proceedings

Keith R. Dienes; Moshe Moshe; Robert C. Myers

1995-06-01

160

Safety rod latch inspection  

SciTech Connect

During an attempt to raise control rods from the 100 K reactor in December, one rod could not be withdrawn. Subsequent investigation revealed that a small ``button`` in the latch mechanism had broken off of the ``lock plunger`` and was wedged in a position that prevented rod withdrawal. Concern that this failure may have resulted from corrosion or some other metallurgical problem resulted in a request that SRL examine six typical latch mechanisms from the 100 L reactor by use of radiography and metallography. During the examination of the L-Area latches, a failed latch mechanism from the 100 K reactor was added to the investigation. Fourteen latches that had a history of problems were removed from K-Area and sent to SRL for inclusion in this study the week after the original seven assemblies were examined, bringing the total of latch assemblies discussed in this report to twenty one. Results of the examination of the K-Area latch that initiated this study is not included in this report.

Leader, D.R.

1992-02-01

161

Safety rod latch inspection  

SciTech Connect

During an attempt to raise control rods from the 100 K reactor in December, one rod could not be withdrawn. Subsequent investigation revealed that a small button'' in the latch mechanism had broken off of the lock plunger'' and was wedged in a position that prevented rod withdrawal. Concern that this failure may have resulted from corrosion or some other metallurgical problem resulted in a request that SRL examine six typical latch mechanisms from the 100 L reactor by use of radiography and metallography. During the examination of the L-Area latches, a failed latch mechanism from the 100 K reactor was added to the investigation. Fourteen latches that had a history of problems were removed from K-Area and sent to SRL for inclusion in this study the week after the original seven assemblies were examined, bringing the total of latch assemblies discussed in this report to twenty one. Results of the examination of the K-Area latch that initiated this study is not included in this report.

Leader, D.R.

1992-02-01

162

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

163

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

164

Capture and confinement stress in white sucker exposed to bleached kraft pulp mill effluent.  

PubMed

This study evaluates the effects of handling and confinement stress and a 3-day recovery period on a number of biochemical parameters used to monitor exposure of fish to bleached kraft mill effluent (BKME). Plasma was collected at four times of the day from male and female white sucker subjected to four levels of handling stress during their spawning migration at a BKME and a reference site. Indicators of a general response to stress (plasma cortisol, glucose, lactate, and total protein) and of reproductive fitness (plasma testosterone, 11-ketotestosterone, and 17 beta-estradiol) were measured. With the exception of 17 beta-estradiol in females, all of the parameters measured varied with time of day and stress level. The general stress indicators ranged from being highly to marginally responsive to handling and confinement stress and were inconsistent in terms of indicating a site difference. The reproductive steroids were moderately responsive to stress and gave the most consistent site difference with testosterone and 11-ketotestosterone levels reduced in BKME-exposed fish under low levels of stress. There was limited evidence for recovery from capture, handling, and transport in the spring for plasma cortisol, lactate, and 17 beta-estradiol at the BKME site, plasma glucose at the reference site, and plasma testosterone at both sites. Fish were also more responsive to an additional acute stress on Day 1 and Day 3 of recovery compared to that on Day 0. This study emphasizes the need for standardized methods in field collections and sampling with the least amount of stress possible, and suggests that holding white sucker for 1 or 3 days does not allow them to recover from the stress of capture. PMID:8727523

Jardine, J J; Van der Kraak, G J; Munkittrick, K R

1996-04-01

165

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

166

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

Microsoft Academic Search

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

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

1992-01-01

167

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

Microsoft Academic Search

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

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

2006-01-01

168

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

Microsoft Academic Search

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

Leah Bendell Young; Harold H. Harvey

1989-01-01

169

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

Microsoft Academic Search

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

S. Li; P. T. K. Woo

1996-01-01

170

Effect of dark strings on semilocal strings  

SciTech Connect

Dark strings have recently been suggested to exist in new models of dark matter that explain the excessive electronic production in the Galaxy. We study the interaction of these dark strings with semilocal strings which are solutions of the bosonic sector of the standard model in the limitsin{sup 2}{theta}{sub w}=1, where {theta}{sub w} is the Weinberg angle. While embedded Abelian-Higgs strings exist for generic values of the coupling constants, we show that semilocal solutions with nonvanishing condensate inside the string core exist only above a critical value of the Higgs to gauge boson mass ratio when interacting with dark strings. Above this critical value, which is greater than unity, the energy per unit length of the semilocal-dark string solutions is always smaller than that of the embedded Abelian-Higgs-dark string solutions and we show that Abelian-Higgs-dark strings become unstable above this critical value. Different from the noninteracting case, we would thus expect semilocal strings to be stable for values of the Higgs to gauge boson mass ratio larger than unity. Moreover, the one-parameter family of solutions present in the noninteracting case ceases to exist when semilocal strings interact with dark strings.

Brihaye, Yves [Faculte de Sciences, University de Mons, 7000 Mons (Belgium); Hartmann, Betti [School of Engineering and Science, Jacobs University Bremen, 28759 Bremen (Germany)

2009-12-15

171

Inflation, string theory and cosmic strings  

NASA Astrophysics Data System (ADS)

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 (MB) 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.

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

2015-02-01

172

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

173

Cone rod dystrophies.  

PubMed

Cone rod dystrophies (CRDs) (prevalence 1/40,000) are inherited retinal dystrophies that belong to the group of pigmentary retinopathies. CRDs are characterized by retinal pigment deposits visible on fundus examination, predominantly localized to the macular region. In contrast to typical retinitis pigmentosa (RP), also called the rod cone dystrophies (RCDs) resulting from the primary loss in rod photoreceptors and later followed by the secondary loss in cone photoreceptors, CRDs reflect the opposite sequence of events. CRD is characterized by primary cone involvement, or, sometimes, by concomitant loss of both cones and rods that explains the predominant symptoms of CRDs: decreased visual acuity, color vision defects, photoaversion and decreased sensitivity in the central visual field, later followed by progressive loss in peripheral vision and night blindness. The clinical course of CRDs is generally more severe and rapid than that of RCDs, leading to earlier legal blindness and disability. At end stage, however, CRDs do not differ from RCDs. CRDs are most frequently non syndromic, but they may also be part of several syndromes, such as Bardet Biedl syndrome and Spinocerebellar Ataxia Type 7 (SCA7). Non syndromic CRDs are genetically heterogeneous (ten cloned genes and three loci have been identified so far). The four major causative genes involved in the pathogenesis of CRDs are ABCA4 (which causes Stargardt disease and also 30 to 60% of autosomal recessive CRDs), CRX and GUCY2D (which are responsible for many reported cases of autosomal dominant CRDs), and RPGR (which causes about 2/3 of X-linked RP and also an undetermined percentage of X-linked CRDs). It is likely that highly deleterious mutations in genes that otherwise cause RP or macular dystrophy may also lead to CRDs. The diagnosis of CRDs is based on clinical history, fundus examination and electroretinogram. Molecular diagnosis can be made for some genes, genetic counseling is always advised. Currently, there is no therapy that stops the evolution of the disease or restores the vision, and the visual prognosis is poor. Management aims at slowing down the degenerative process, treating the complications and helping patients to cope with the social and psychological impact of blindness. PMID:17270046

Hamel, Christian P

2007-01-01

174

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

Todd F. Hoover

2010-10-01

175

Evidence for string substructure  

SciTech Connect

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

Bergman, O.

1996-06-01

176

Vacuum String Field Theory  

Microsoft Academic Search

This is a brief review of vacuum string field theory, a new approach to open string field theory based on the stable vacuum of the tachyon. We discuss the sliver state explaining its role as a projector in the space of half-string functionals. We review the construction of D-brane solutions in vacuum string field theory, both in the algebraic approach

Leonardo Rastelli; Ashoke Sen; Barton Zwiebach

2001-01-01

177

Constraint Reasoning Over Strings  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

178

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

179

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

180

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

2013-06-02

181

Chemical and Ecological Health of White Sucker (Catostomus Commersoni) in Rock Creek Park, Washington, D.C., 2003-04  

USGS Publications Warehouse

Several classes of chemicals that are known or suspected contaminants were found in bed sediment in Rock Creek, including polyaromatic hydrocarbons (PAHs), phthalate esters, organochlorine pesticides, dioxins and furans, trace metals and metalloids (mercury, arsenic, cadmium, chromium, cobalt, copper, lead, nickel, silver, and zinc), and polychlorinated biphenyls (total PCBs and selected aroclors). Concentrations of many of these chemicals consistently exceeded threshold or chronic-effects guidelines for the protection of aquatic life and often exceeded probable effects levels (PELs). Exceedance of PELs was dependent on the amount of total organic carbon in the sediments. Concurrent with the collection of sediment-quality data, white sucker (Catostomus commersoni) were evaluated for gross-external and internal-organ anomalies, whole-body burdens of chemical contaminants, and gut contents to determine prey. The histopathology of internal tissues of white sucker was compared to contaminant levels in fish tissue and bed sediment. Gut contents were examined to determine preferential prey and thus potential pathways for the bioaccumulation of chemicals from bed sediments. Male and female fish were tested separately. Lesions and other necroses were observed in all fish collected during both years of sample collection, indicating that fish in Rock Creek have experienced some form of environmental stress. No direct cause and effect was determined for chemical exposure and compromised fish health, but a substantial weight of evidence indicates that white sucker, which are bottom-feeding fish and low-order consumers in Rock Creek, are experiencing some reduction in vitality, possibly due to immunosuppression. Abnormalities observed in gonads of both sexes of white sucker and observations of abnormal behavior during spawning indicated some interruption in reproductive success.

Miller, Cherie V.; Weyers, Holly S.; Blazer, Vicki S.; Freeman, Mary E.

2006-01-01

182

Chemical and ecological health of white sucker (Catostomus Commersoni) in Rock Creek Park, Washington, D.C., 2003?04  

USGS Publications Warehouse

Several classes of chemicals that are known or suspected contaminants were found in bed sediment in Rock Creek, including polyaromatic hydrocarbons (PAHs), phthalate esters, organochlorine pesticides, dioxins and furans, trace metals and metalloids (mercury, arsenic, cadmium, chromium, cobalt, copper, lead, nickel, silver, and zinc), and polychlorinated biphenyls (total PCBs and selected aroclors). Concentrations of many of these chemicals consistently exceeded thresholdor chronic-effects guidelines for the protection of aquatic life and often exceeded probable effects levels (PELs). Exceedance of PELs was dependent on the amount of total organic carbon in the sediments. Concurrent with the collection of sediment-quality data, white sucker (Catostomus commersoni) were evaluated for gross-external and internal-organ anomalies, whole-body burdens of chemical contaminants, and gut contents to determine prey. The histopathology of internal tissues of white sucker was compared to contaminant levels in fish tissue and bed sediment. Gut contents were examined to determine preferential prey and thus potential pathways for the bioaccumulation of chemicals from bed sediments. Male and female fish were tested separately. Lesions and other necroses were observed in all fish collected during both years of sample collection, indicating that fish in Rock Creek have experienced some form of environmental stress. No direct cause and effect was determined for chemical exposure and compromised fish health, but a substantial weight of evidence indicates that white sucker, which are bottom-feeding fish and low-order consumers in Rock Creek, are experiencing some reduction in vitality, possibly due to immunosuppression. Abnormalities observed in gonads of both sexes of white sucker and observations of abnormal behavior during spawning indicated some interruption in reproductive success.

Miller, C.V.; Weyers, H.S.; Blazer, V.S.; Freeman, M.E.

2006-01-01

183

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

184

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

Microsoft Academic Search

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

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

2010-01-01

185

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

Microsoft Academic Search

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

Leah I. Bendell-Young; Harold H. Harvey

1986-01-01

186

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

187

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

Microsoft Academic Search

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

Jocelyn Dorval; Vincent Leblond; Christian Deblois; Alice Hontela

2005-01-01

188

Survival Rates and Movement of Hatchery-Reared Razorback Suckers in the Upper Colorado River Basin, Utah and Colorado  

Microsoft Academic Search

We used tag–recapture data to estimate apparent survival and capture probability for 119,129 hatchery-reared, federally endangered razorback suckers Xyrauchen texanus stocked into upper Colorado River basin streams during 1995–2005. Effects investigated included reach, year, and season of stocking; fish total length (TL) at time of stocking; survival in the first year after stocking versus in subsequent years; and sampling effort.

Koreen A. Zelasko; Kevin R. Bestgen; Gary C. White

2010-01-01

189

Effects of ambient Lake Mohave temperatures on development, oxygen consumption, and hatching success of the razorback sucker  

Microsoft Academic Search

Spawning of razorback suckers,Xyrauchen texanus, in Lake Mohave occurred from 10–22°C and larvae were collected at water temperatures from 10–15°C in 1982 and 1983. In the laboratory, hatching success was similar from 12–20°C, but reduced hatching success was found at 10°C while none hatched a 8°C. Development rate and oxygen consumption were positively related to incubation temperature. Direct effects of

Michael A. Bozekl; Larry J. Paulson; Gene R. Wilde

1990-01-01

190

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

USGS Publications Warehouse

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

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

1998-01-01

191

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

192

Nonsupersymmetric string solitons  

Microsoft Academic Search

We begin a search for nonsupersymmetric\\/supersymmetric dual string pairs by constructing candidate critical nonsupersymmetric strings as solitons in supersymmetric string theories. Using orbifold techniques, one can construct cosmic string solutions which lie in supersymmetric vacua but which do not fall in supermultiplets. We discuss two three-dimensional examples in detail. The effective worldsheet actions for the soliton strings have (0,2) and

Shamit Kachru; Eva Silverstein

1995-01-01

193

Tag loss and short-term mortality associated with passive integrated transponder tagging of juvenile Lost River suckers  

USGS Publications Warehouse

Passive integrated transponder (PIT) tags are commonly used to mark small catostomids, but tag loss and the effect of tagging on mortality have not been assessed for juveniles of the endangered Lost River sucker Deltistes luxatus. I evaluated tag loss and short-term (34-d) mortality associated with the PIT tagging of juvenile Lost River suckers in the laboratory by using a completely randomized design and three treatment groups (PIT tagged, positive control, and control). An empty needle was inserted into each positive control fish, whereas control fish were handled but not tagged. Only one fish expelled its PIT tag. Mortality rate averaged 9.8 ± 3.4% (mean ± SD) for tagged fish; mortality was 0% for control and positive control fish. All tagging mortalities occurred in fish with standard lengths of 71 mm or less, and most of the mortalities occurred within 48 h of tagging. My results indicate that 12.45- × 2.02-mm PIT tags provide a viable method of marking juvenile Lost River suckers that are 72 mm or larger.

Burdick, Summer M.

2011-01-01

194

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

195

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

SciTech Connect

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.

Munkittrick, K.R.; Dixon, D.G. (Univ. of Waterloo, Ontario (Canada))

1989-08-01

196

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

USGS Publications Warehouse

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

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

2010-01-01

197

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

198

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

199

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

200

String axiverse  

SciTech Connect

String theory suggests the simultaneous presence of many ultralight axions, possibly populating each decade of mass down to the Hubble scale 10{sup -33} eV. Conversely the presence of such a plenitude of axions (an axiverse) would be evidence for string theory, since it arises due to the topological complexity of the extra-dimensional manifold and is ad hoc in a theory with just the four familiar dimensions. We investigate how several upcoming astrophysical experiments will be observationally exploring the possible existence of such axions over a vast mass range from 10{sup -33} eV to 10{sup -10} eV. Axions with masses between 10{sup -33} eV to 10{sup -28} eV can cause a rotation of the cosmic microwave background polarization that is constant throughout the sky. The predicted rotation angle is independent of the scale of inflation and the axion decay constant, and is of order {alpha}{approx}1/137-within reach of the just launched Planck satellite. Axions in the mass range 10{sup -28} eV to 10{sup -18} eV give rise to multiple steps in the matter power spectrum, providing us with a snapshot of the axiverse that will be probed by galaxy surveys-such as BOSS, and 21 cm line tomography. Axions in the mass range 10{sup -22} eV to 10{sup -10} eV can affect the dynamics and gravitational wave emission of rapidly rotating astrophysical black holes through the Penrose superradiance process. When the axion Compton wavelength is of order of the black hole size, the axions develop superradiant atomic bound states around the black hole nucleus. Their occupation number grows exponentially by extracting rotational energy and angular momentum from the ergosphere, culminating in a rotating Bose-Einstein axion condensate emitting gravitational waves. For black holes lighter than {approx}10{sup 7} solar masses accretion cannot replenish the spin of the black hole, creating mass gaps in the spectrum of rapidly rotating black holes that diagnose the presence of destabilizing axions. In particular, the highly rotating black hole in the X-ray binary LMC X-1 implies an upper limit on the decay constant of the QCD axion f{sub a} < or approx. 2x10{sup 17} GeV, much below the Planck mass. This reach can be improved down to the grand unification scale f{sub a}< or approx. 2x10{sup 16} GeV, by observing smaller stellar mass black holes.

Arvanitaki, Asimina [Berkeley Center for Theoretical Physics, University of California, Berkeley, California, 94720 (United States); Theoretical Physics Group, Lawrence Berkeley National Laboratory, Berkeley, California, 94720 (United States); Dimopoulos, Savas [Department of Physics, Stanford University, Stanford, California 94305 (United States); Dubovsky, Sergei [Department of Physics, Stanford University, Stanford, California 94305 (United States); Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary Prospect, 7a, 117312 Moscow (Russian Federation); Kaloper, Nemanja [Department of Physics, University of California, Davis, California 95616 (United States); March-Russell, John [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford (United Kingdom)

2010-06-15

201

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

202

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

SciTech Connect

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

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

1995-02-01

203

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

204

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

PubMed

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 (N b /N a) increased significantly despite sevenfold reduction of N a. 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

2014-03-01

205

String and string-inspired phenomenology  

Microsoft Academic Search

In these lectures I review the progress made over the last few years in the subject of string and string-inspired phenomenology. I take a practical approach, thereby concentrating more on explicit examples rather than on formal developments. Topics covered include: introduction to string theory, the free-fermionic formulation and its general features, generic conformal field theory properties, $SU(5)\\\\times U(1)$ GUT and

Jorge L. Lopez

1995-01-01

206

String and string-inspired phenomenology  

Microsoft Academic Search

In these lectures I review the progress made over the last few years in the\\u000asubject of string and string-inspired phenomenology. I take a practical\\u000aapproach, thereby concentrating more on explicit examples rather than on formal\\u000adevelopments. Topics covered include: introduction to string theory, the\\u000afree-fermionic formulation and its general features, generic conformal field\\u000atheory properties, $SU(5)\\\\times U(1)$ GUT and

JORGE L. LOPEZ

1994-01-01

207

Status of rod consolidation, 1988  

SciTech Connect

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

Bailey, W.J.

1989-01-01

208

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.

Michael Green

2012-06-26

209

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

210

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

211

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

212

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

213

String Gyratons in Supergravity  

E-print Network

We study solutions of the supergravity equations with the string-like sources moving with the speed of light. An exact solution is obtained for the gravitational field of a boosted ring string in any dimension greater than three.

Valeri P. Frolov; Feng-Li Lin

2006-05-10

214

Dynamics of Linear Piezoelectric Rods  

Microsoft Academic Search

A one-dimensional model of a linear piezoelectric thin rod is deduced from three-dimensional piezoelectricity by introducing suitable internal constraints and appropriate hypotheses on the electric displacement field.

F. DavÍ

1997-01-01

215

The string theory landscape  

NASA Astrophysics Data System (ADS)

Perhaps the most important way string theory has affected the perspective of particle physics phenomenology is through the "string theory landscape". We discuss the evidence supporting its existence, describe the regions of the landscape that have been explored, and examine what the string theory landscape might imply for most Standard Model problems.

Schellekens, A. N.

2015-01-01

216

The String Theory Landscape  

NASA Astrophysics Data System (ADS)

Perhaps the most important way string theory has affected the perspective of particle physics phenomenology is through the "string theory landscape". We discuss the evidence supporting its existence, describe the regions of the landscape that have been explored, and examine what the string theory landscape might imply for most Standard Model problems.

Schellekens, A. N.

2014-12-01

217

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

2003-01-27

218

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

219

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

220

Topics in String Phenomenology  

Microsoft Academic Search

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

Michael Dine

1993-01-01

221

Nuclear design of Helical Cruciform Fuel rods  

SciTech Connect

In order to increase the power density of current and new light water reactor designs, the Helical Cruciform Fuel (HCF) rods are proposed. The HCF rods are equivalent to a cylindrical rod, with the fuel in a cruciform shaped, twisted axially. The HCF rods increase the surface area to volume ratio and inter-subchannel mixing behavior due to their cruciform and helical shapes, respectively. In a previous study, the HCF rods have shown the potential to up-rate existing PWRs by 50% and BWRs by 25%. However, HCF rods do display different neutronics modeling and performance. The cruciform cross section of HCF rods creates radially asymmetric heat generation and temperature distribution. The nominal HCF rod's beginning of life reactivity is reduced, compared to a cylindrical rod with the same fuel volume, by 500 pcm, due to increase in absorption in cladding. The rotation of these rods accounts for reactivity changes, which depends on the H/HM ratio of the pin cell. The HCF geometry shows large sensitivities to U{sup 235} or gadolinium enrichments compared to a cylindrical geometry. In addition, the gadolinium-containing HCF rods show a stronger effect on neighboring HCF rods than in case of cylindrical rods, depending on the orientation of the HCF rods. The helical geometry of the rods introduces axial shadowing of about 600 pcm, not seen in typical cylindrical rods. (authors)

Shirvan, K.; Kazimi, M. S. [Dept. of Nuclear Engineering and Sciences, Massachusetts Inst. of Technology, 77 Massachusetts Avenue 24-215 (United States)

2012-07-01

222

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

223

Impact of selenium and other trace elements on the endangered adult razorback sucker.  

PubMed

A study was conducted with endangered the razorback sucker (Xyrauchen texanus) to determine if environmental exposure to selenium in flooded bottomland sites affected survival, growth, and egg-hatching success. Adults were stocked at three sites adjacent to the Colorado River near Grand Junction, Colorado, in July 1996: hatchery ponds at Horsethief Canyon State Wildlife Area (referred to here as Horsethief; the reference site), a diked tertiary channel at Adobe Creek, and North Pond at Walter Walker State Wildlife Area (WWSWA). Fish were collected in April 1997 and spawned. After two spawnings adults from the three sites were held at Horsethief for an 86-day selenium depuration period. Selenium concentrations at Horsethief were 1.4-3.0 microg/L in water, 0.8-0.9 microg/g in sediment, 4.5 microg/g in muscle plug, and 6.0 microg/g in eggs; at Adobe Creek, <0.7-4.5 microg/L in water, 1.2-2.5 microg/g in sediment, 16-20 microg/g in zooplankton, 9.6 microg/g in muscle plug, and 40 microg/g in eggs; and at North Pond, 3.2-17 microg/L in water, 16-94 microg/g in sediment, 32-48 microg/g in zooplankton, 14 microg/g in muscle plug, and 55 microg/g in eggs. During the depuration period, when adults from Adobe Creek and North Pond were held at Horsethief, the fish lost 7%-13% of their selenium burden in 59 days and 14%-21% in 86 days. Larvae from North Pond adults had the most deformities, followed by Adobe Creek adults, with the fewest deformities found in the Horsethief adults. PMID:12203951

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

2002-01-01

224

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

225

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

226

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

227

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

228

Influence of cytokinin levels on in vitro propagation of shy suckering chrysanthemum “Arka Swarna” and activation of endophytic bacteria  

Microsoft Academic Search

In an effort to develop a sustainable protocol for the micropropagation of a shy suckering elite chrysanthemum cv. Arka Swarna\\u000a (yellow pompon type), in vitro cultures were established using surface-sterilized nodal microcuttings (1–1.5 cm) from polyhouse-grown plants on MS medium\\u000a containing 3% sucrose, 0.25% phytagel, and 5 ?M benzyl adenine (BA) or kinetin. Microbial contamination in the range of 6–24%\\u000a was encountered

Bindu Panicker; Pious Thomas; Tolety Janakiram; Rangarajan Venugopalan; Sathyanarayana B. Narayanappa

2007-01-01

229

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

Microsoft Academic Search

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

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

1986-01-01

230

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

231

An Open String Landscape  

E-print Network

The effect of fluxes on open string moduli is studied by analyzing the constraints imposed by supersymmetry on D-branes in type IIB flux backgrounds. We show that generically the conditions of supersymmetry cannot be maintained when moving along the geometrical moduli space of the brane, so that open string moduli are lifted. We argue that there is a disconnected and discrete set of supersymmetric solutions to the open string equations of motion, which extends the familiar closed string landscape to the open string sector.

Jaume Gomis; Fernando Marchesano; David Mateos

2005-11-16

232

The nonlinear bending-torsion theory for curved rods as Gamma-limit of three-dimensional elasticity  

E-print Network

The problem of the rigorous derivation of one-dimensional models for nonlinearly elastic curved beams is studied in a variational setting. Considering different scalings of the three-dimensional energy and passing to the limit as the diameter of the beam goes to zero, a nonlinear model for strings and a bending-torsion theory for rods are deduced.

Lucia Scardia

2008-03-06

233

Closed strings from nothing  

SciTech Connect

We study the physics of open strings in bosonic and type-II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the perturbative spectrum. We explore the scenario of Yi and of Bergman, Hori, and Yi, who argue that the open string degrees of freedom are strongly coupled and disappear through confinement. We discuss arguments using open string field theory and world sheet boundary renormalization group flows, which seem to indicate otherwise. We then describe a solitonic excitation of the open string tachyon and gauge field with the charge and tension of a fundamental closed string. This requires a double scaling limit where the tachyon is taken to its minimal value and the electric field is taken to its maximum value. The resulting flux tube has an unconstrained spatial profile; and for large fundamental string charge it appears to have light, weakly coupled open strings existing in the core. We argue that the flux tube acquires a size of order {alpha}' through sigma model and string coupling effects, and that confinement effects make the light degrees of freedom heavy and strongly interacting.

Kleban, Matthew; Lawrence, Albion; Shenker, Stephen

2001-09-15

234

Closed Strings From Nothing  

SciTech Connect

We study the physics of open strings in bosonic and type II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the perturbative spectrum. We explore the scenario of Yi and of Bergman, Hori and Yi, who argue that the open string degrees of freedom are strongly coupled and disappear through confinement. We discuss arguments using open string field theory and worldsheet boundary RG flows, which seem to indicate otherwise. We then describe a solitonic excitation of the open string tachyon and gauge field with the charge and tension of a fundamental closed string. This requires a double scaling limit where the tachyon is taken to its minimal value and the electric field is taken to its maximum value. The resulting flux tube has an unconstrained spatial profile; and for large fundamental string charge, it appears to have light, weakly coupled open strings living in the core. We argue that the flux tube acquires a size or order {alpha}' through sigma model and string coupling effects; and we argue that confinement effects make the light degrees of freedom heavy and strongly interacting.

Lawrence, Albion

2001-07-25

235

Rod gripper, changer, and storage system  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

236

Finite volume approach for the instationary Cosserat rod model describing the spinning of viscous jets  

E-print Network

The spinning of slender viscous jets can be described asymptotically by one-dimensional models that consist of systems of partial and ordinary differential equations. Whereas the well-established string models possess only solutions for certain choices of parameters and set-ups, the more sophisticated rod model that can be considered as $\\epsilon$-regularized string is generally applicable. But containing the slenderness ratio $\\epsilon$ explicitely in the equations complicates the numerical treatment. In this paper we present the first instationary simulations of a rod in a rotational spinning process for arbitrary parameter ranges with free and fixed jet end, for which the hitherto investigations longed. So we close an existing gap in literature. The numerics is based on a finite volume approach with mixed central, up- and down-winded differences, the time integration is performed by stiff accurate Radau methods.

Walter Arne; Nicole Marheineke; Andreas Meister; Raimund Wegener

2012-07-03

237

Finite volume approach for the instationary Cosserat rod model describing the spinning of viscous jets  

E-print Network

The spinning of slender viscous jets can be described asymptotically by one-dimensional models that consist of systems of partial and ordinary differential equations. Whereas the well-established string models possess only solutions for certain choices of parameters and set-ups, the more sophisticated rod model that can be considered as $\\epsilon$-regularized string is generally applicable. But containing the slenderness ratio $\\epsilon$ explicitely in the equations complicates the numerical treatment. In this paper we present the first instationary simulations of a rod in a rotational spinning process for arbitrary parameter ranges with free and fixed jet end, for which the hitherto investigations longed. So we close an existing gap in literature. The numerics is based on a finite volume approach with mixed central, up- and down-winded differences, the time integration is performed by stiff accurate Radau methods.

Arne, Walter; Meister, Andreas; Wegener, Raimund

2012-01-01

238

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

239

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

240

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

241

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

242

When Strings Collide: The Gravitational Interaction of Conical Strings  

E-print Network

When Strings Collide: The Gravitational Interaction of Conical Strings Charles Hellaby1 General fields of the strings, and 1 Applied Mathematics, University of Cape Town, Rondebosch, 7701, South Africa

Hellaby, Charles

243

Cadmium safety rod thermal tests  

SciTech Connect

Thermal testing of cadmium safety rods was conducted as part of a program to define the response of Savannah River Site (SRS) production reactor core components to a hypothetical LOCA leading to a drained reactor tank. The safety rods are present in the reactor core only during shutdown and are not used as a control mechanism during operation; thus, their response to the conditions predicted for the LOCA is only of interest to the extent that it could impact the progression of the accident. This document provides a description of this testing.

Thomas, J.K.; Iyer, N.C.; Peacock, H.B.

1992-01-01

244

Cadmium safety rod thermal tests  

SciTech Connect

Thermal testing of cadmium safety rods was conducted as part of a program to define the response of Savannah River Site (SRS) production reactor core components to a hypothetical LOCA leading to a drained reactor tank. The safety rods are present in the reactor core only during shutdown and are not used as a control mechanism during operation; thus, their response to the conditions predicted for the LOCA is only of interest to the extent that it could impact the progression of the accident. This document provides a description of this testing.

Thomas, J.K.; Iyer, N.C.; Peacock, H.B.

1992-07-01

245

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

246

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

2014-08-19

247

Tuning Rod-Rod Interactions in Poly(3-alkylthiophene) Derivatives  

NASA Astrophysics Data System (ADS)

Poly(3-alkylthiophene) (P3AT) derivatives are used commonly in polymer semiconducting applications. However, during the coating of P3AT thin films strong intermolecular interactions generally lead to the formation of semiconducting fibers. This prevents the formation of long-range ordered domains and complicates analysis of structure-property relationships in P3AT-containing devices (e.g., organic photovoltaic cells). Here, we show rod-rod interactions can be controlled by rational polythiophene side chain design. The effects of side chain passivation are evidenced by a depressed melting temperature and the presence of a liquid crystalline region. We show also that while the rod-rod interactions are lowered significantly in a polythiophene derivative with a branched side chain relative to straight chain P3ATs, the optoelectronic properties remain approximately constant. Importantly, this reduced melting temperature allows for the real-time evolution of a P3AT crystal structure at room temperature to be monitored on an experimentally convenient time scale. These structural data correlate well with field-effect charge carrier mobility measurements and provide a path for studying the mechanism of ordering in plastic electronics.

Boudouris, Bryan; Ho, Victor; Segalman, Rachel

2011-03-01

248

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

249

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

250

Tagging age-1 Lost River and shortnose suckers with passive integrated transponders, Upper Klamath Lake, Oregon–Summary of 2009–11 effort  

USGS Publications Warehouse

A passive integrated transponder (PIT) tagging study was initiated in 2009 for age-1 endangered Lost River and shortnose suckers in Upper Klamath Lake, Oregon, for the purpose of examining causes of mortality, validating estimated age to maturity, and examining movement patterns. This study, which was done opportunistically in 2009 and 2010, received funding in 2011 for a directed tagging effort. Tags were redetected using an existing infrastructure of remote PIT tag readers and tag scanning surveys at American white pelican and double-crested cormorant breeding and loafing areas. Individual fish histories are used to describe the distance, direction, and timing of age-1 sucker movement. Sucker PIT tag detections in the Sprague and Williamson rivers in mid-summer and in autumn indicate age-1 suckers use these tributaries outside of the known spring spawning season. PIT tags detected in bird habitats indicate predation by birds may have been a cause of mortality in 2009. Field conditions prevented scanning bird breeding and loafing areas in Upper Klamath Wildlife National Refuge for tags in 2011, however, limiting our ability to make inferences about bird predation in those years.

Burdick, Summer M.

2012-01-01

251

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

Microsoft Academic Search

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

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

2006-01-01

252

Effects of pool formation and flash flooding on relative abundance of young-of-year flannelmouth suckers in the Paria River, Arizona  

Microsoft Academic Search

Flannelmouth sucker, Catostomus latipinnis, a fish endemic to the Colorado River basin in the western United States, appears to experience poor recruitment to adult size in the Colorado River, downstream of Glen Canyon Dam. Lack or impermanence of rearing areas for young-of-year (YOY) fish is hypothesized to be the problem. Knowing the importance of tributary mouths as rearing areas in

Michele L. Thieme; Mark J. Brouder; Timothy L. Hoffnagle

2001-01-01

253

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

PubMed

In Spring 2011, 200 adult white sucker were collected in four areas of the St. Louis River area of concern (AOC), located in Minnesota and Wisconsin, USA. The areas included the upper AOC as a reference area, the upper estuary, St. Louis Bay and Superior Bay. Grossly visible abnormalities were documented and preserved for microscopic analyses, as were five to eight representative pieces of liver tissue. A piece of dorsal muscle was preserved for stable isotope analyses and otoliths removed for age determination. The incidence of raised skin lesions (mucoid plaques) was high (31 %), however, microscopically only 4.5 % of the white suckers had neoplasia (papillomas). The remaining lesions were epidermal hyperplasia. Superior Bay had the lowest percentage of skin/lip lesions (10 %), while St. Louis Bay had the highest (44 %). St. Louis Bay also had the highest incidence of skin neoplasms (12 %). No hepatocellular neoplasms were documented, however bile duct tumors were observed in 4.5 % of the suckers. Foci of cellular alteration were observed in fish from all sites except the upper AOC. Stable isotope data indicated that most of the suckers relied on the St. Louis River AOC for the majority (>75 %) of their diet, indicating they were resident within the AOC and not in Lake Superior. The amount of diet obtained from the upper estuary was a significant predictor of skin lesion incidence. Hence, habitat use within the AOC appears to be an important risk factor for skin and possibly, liver lesions. PMID:24370817

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

2014-03-01

254

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...

255

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

Microsoft Academic Search

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

Patrice Hamel; Pierre Magnan; Michèle Lapointe; Pierre East

1997-01-01

256

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

Microsoft Academic Search

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

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

1999-01-01

257

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

Microsoft Academic Search

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

CHARLOTTE HAYWOOD; MARY JEANNE CLAPP

258

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

Microsoft Academic Search

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

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

2009-01-01

259

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

260

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

261

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

262

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

263

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

USGS Publications Warehouse

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

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

2009-01-01

264

21 CFR 876.4270 - Colostomy rod.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

265

21 CFR 876.4270 - Colostomy rod.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

266

21 CFR 876.4270 - Colostomy rod.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

267

21 CFR 876.4270 - Colostomy rod.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

268

21 CFR 876.4270 - Colostomy rod.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

269

Genetics Home Reference: Intranuclear rod myopathy  

MedlinePLUS

... of individuals. Its exact prevalence is unknown. What genes are related to intranuclear rod myopathy? Intranuclear rod ... is caused by a mutation in the ACTA1 gene. This gene provides instructions for making a protein ...

270

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.

271

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

272

Holography in string theory  

NASA Astrophysics Data System (ADS)

This thesis presents three aspects of holography, or holographic duality, in string theory. The goal of holography is to describe gravitational theories by field theories in fewer dimensions. Although recently there have been significant strides toward understanding generic holographic dualities between particle theory and gravity, it is not clear how string theory might implement this. In Chapter 2 the role of compact directions in holography is explored. We discover that a generalization of Bousso's prescription is necessary. In this chapter we also discover that holography provides no clear solution to understanding closed timelike curves, unlike earlier speculation. Using holography as a tool, we are able in Chapter 3 to compute the thermal two-point function of the graviton in the dual to a Little String Theory. This is a strongly coupled non-gravitational theory. It exists as a limit of a certain weakly coupled string theory. We find a typical thermal spectrum with no obvious interpretation in terms of particles and bound states. We find evidence supporting a conjecture that this theory is thermodynamically unstable. Finally, in Chapter 4, we investigate the inhomogeneous decay of an unstable D-brane. We study the average number and energy of closed strings emitted during the decay, and confirm that the space-filling D-brane decays completely into lower-dimensional D-branes. One of the long-term goals of this research is to understand how closed-string fluctuations appear in the open-string sector of string theory. This is directly related to the appearance of holography in string theory since gravity appears in the closed-string sector, while the end-points of open strings can be described by field theory.

Deboer, Philip Albert

273

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

274

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

SciTech Connect

Recent studies have demonstrated reproductive problems in white sucker (Catostomus commersoni) exposed to bleached kraft pulp mill effluent (BKME) at Jackfish Bay on Lake Superior. These fish exhibit delayed sexual maturity, reduced gonadal size, reduced secondary sexual characteristics, and circulating steroid levels depressed relative to those of reference populations. The present studies were designed to evaluate sites in the pituitary-gonadal axis of prespawning white sucker affected by BKME exposure. At the time of entry to the spawning stream, plasma levels of immunoreactive gonadotropin (GtH)-II (LH-type GtH) in male and female white sucker were 30- and 50-fold lower, respectively, than the levels in fish from a reference site. A single intraperitoneal injection of D-Arg6, Pro9N-Et sGnRH (sGnRH-A, 0.1 mg/kg) increased plasma GtH levels in male and female fish at both sites, although the magnitude of the response was greatly reduced in BKME-exposed fish. Fish at the BKME site did not ovulate in response to sGnRH-A, while 10 of 10 fish from the reference site ovulated within 6 hr. Plasma 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P) levels were depressed in BKME-exposed fish and unlike fish at the reference site, failed to increase in response to sGnRH-A. Testosterone levels in both sexes and 11-ketostestosterone levels in males were elevated in fish from the reference site but were not further increased by GnRH treatment. In contrast, BKME-exposed fish exhibit a transitory increase in testosterone levels in response to the GnRH analog. In vitro incubations of ovarian follicles obtained from fish at the BKME site revealed depressed basal secretion of testosterone and 17,20 beta-P and reduced responsiveness to the GtH analog human chorionic gonadotropin and to forskolin, a direct activator of adenylate cyclase.

Van Der Kraak, G.J.; Munkittrick, K.R.; McMaster, M.E.; Portt, C.B.; Chang, J.P. (Department of Zoology, University of Guelph, Ontario (Canada))

1992-08-01

275

Longitudinal wave propagation in piezoelectric coupled rods  

Microsoft Academic Search

This paper presents the results of longitudinal wave propagation in piezoelectric coupled rod structures. The deduction of non-dispersive or dispersive characteristics of the structures is based on a classical rod model and the Mindlin-Herrmann rod model. In the classical model, correction factors for piezoelectric effects are introduced to provide remedy for the discontinuity of the normal stress at the interface

Q. Wang; V. K. Varadan

2002-01-01

276

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

277

CONTROL-ROD DRIVE FOR HTGR's  

Microsoft Academic Search

A design is given ior a control-rod drive for high temperature gas-; cooled reactors. Each control rod is individually driven by means oi a rack and ; pinion at its lower end. The energy of the falling rod is absorbed through the ; use of a ball-nut-hydraulic cylinder arrangement. (C.J.G.);

C. A. Kroeber; J. M. Welch

1959-01-01

278

49 CFR 236.793 - Rod, lock.  

Code of Federal Regulations, 2014 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...

2014-10-01

279

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

280

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

281

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

282

String Cosmology and Chaos  

NASA Astrophysics Data System (ADS)

We briefly review two aspects of string cosmology: (1) the presence of chaos in the generic cosmological solutions of the tree-level low-energy effective actions coming out of string theory, and (2) the remarkable link between the latter chaos and the Weyl groups of some hyperbolic Kac-Moody algebras.

Damour, Thibault

283

Chaos in string cosmology  

NASA Astrophysics Data System (ADS)

We briefly review two aspects of string cosmology: 1) the presence of chaos in the generic cosmological solutions of the tree-level low-energy effective actions coming out of string theory, and 2) the remarkable link between the latter chaos and the Weyl groups of some hyperbolic Kac-Moody algebras.

Damour, T.

2003-10-01

284

Extreme Cosmic String  

E-print Network

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

P. F. Gonzalez-Diaz

1995-08-28

285

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

286

String Theory and Beyond  

Microsoft Academic Search

This is the written version of a short talk given at the University of Leipzig in December 1998. It reviews some general aspects of string theory from the viewpoint of the search for an unifying theory. Here, special emphasis lies on the motivation to consider string theory not only as the leading candidate for the unification of gravity and the

M. Rudolph; Theoretische Physik

1998-01-01

287

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

288

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

1999-07-17

289

Crystalline beams: The string  

SciTech Connect

The authors study the possibility of storing a string of charged particles in a magnetic ring. They define the equilibrium configuration, and examine the confinement conditions. Subsequent, they derive the transfer matrix for motion through a drift, a quadrupole, and a dipole. They finally study the stability of the string as the space-charge force is increased.

Haffmans, A.F.; Maletic, D.; Ruggiero, A.G.

1994-04-30

290

Topics on String Phenomenology  

Microsoft Academic Search

These lectures present some topics of string phenomenology and contain two parts. In the first part, I review the possibility of lowering the string scale in the TeV region, that provides a theoretical framework for solving the mass hierarchy problem and unifying all interactions. The apparent weakness of gravity can then be accounted by the existence of large internal dimensions,

Ignatios Antoniadis

2007-01-01

291

String Theory Phenomenology  

Microsoft Academic Search

We review the qualitative features of string theory compactifications with low energy effective theory close to (supersymmetric versions of) the Standard Model of Particle Physics. We cover Calabi-Yau compactifications of heterotic strings, intersecting brane models, and the recent setup of F-theory models.

Angel Uranga

2010-01-01

292

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

293

PT-symmetric strings  

SciTech Connect

We study both analytically and numerically the spectrum of inhomogeneous strings with PT-symmetric density. We discuss an exactly solvable model of PT-symmetric string which is isospectral to the uniform string; for more general strings, we calculate exactly the sum rules Z(p)??{sub n=1}{sup ?}1/E{sub n}{sup p}, with p=1,2,… and find explicit expressions which can be used to obtain bounds on the lowest eigenvalue. A detailed numerical calculation is carried out for two non-solvable models depending on a parameter, obtaining precise estimates of the critical values where pair of real eigenvalues become complex. -- Highlights: •PT-symmetric Hamiltonians exhibit real eigenvalues when PT symmetry is unbroken. •We study PT-symmetric strings with complex density. •They exhibit regions of unbroken PT symmetry. •We calculate the critical parameters at the boundaries of those regions. •There are exact real sum rules for some particular complex densities.

Amore, Paolo, E-mail: paolo.amore@gmail.com [Facultad de Ciencias, CUICBAS, Universidad de Colima, Bernal Díaz del Castillo 340, Colima, Colima (Mexico); Fernández, Francisco M., E-mail: fernande@quimica.unlp.edu.ar [INIFTA (UNLP, CCT La Plata-CONICET), División Química Teórica, Diag. 113 y 64 (S/N), Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina); Garcia, Javier [INIFTA (UNLP, CCT La Plata-CONICET), División Química Teórica, Diag. 113 y 64 (S/N), Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina); Gutierrez, German [Facultad de Ciencias, CUICBAS, Universidad de Colima, Bernal Díaz del Castillo 340, Colima, Colima (Mexico)

2014-04-15

294

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

295

Fates of metal radiotracers added to a whole lake: accumulation in slimy sculpin (Cottus cognatus) and white sucker (Catostomus commersoni).  

PubMed

Six gamma-emitting isotopes, iron-59, cobalt-60, zinc-65, selenium-75, cesium-134 and mercury-203, were added in mid-summer to Lake 224 of the Experimental Lakes Area in northwestern Ontario, Canada. Isotope activities in whole bodies of slimy sculpins and in blood, gills, gut contents, kidney, liver and spleen of white suckers were determined for periods up to 247 days after isotope addition. Results demonstrate delay between contamination of a lake and transfer of contaminant to these fish species. General relationships between movement and distribution of isotopes in water and their accumulation in these fish indicate that direct accumulation from water is not a major route of uptake. PMID:6879149

Klaverkamp, J F; Turner, M A; Harrison, S E; Hesslein, R H

1983-06-01

296

Levonorgestrel concentrations during use of levonorgestrel rod (LNG ROD) implants  

Microsoft Academic Search

In a three-year randomized trial that included 398 women, blood samples were collected for the purpose of assaying levonorgestrel concentrations in women using a new two-rod contraceptive implant system or an earlier implant formulation, Norplant®-2 implants. Sample collection was at 1, 3, 6, 9, and 12 months after placement and semiannually thereafter through three years. Resulting assays and analyses showed

Irving Sivin; Pekka Lähteenmäki; Sirpa Ranta; Philip Darney; Cindy Klaisle; Livia Wan; Daniel R. Mishell; Maria Lacarra; Osborn A. C. Viegas; Prapas Bilhareus; Suporn Koetsawang; Manee Piya-Anant; Soledad Diaz; Margarita Pavez; Francisco Alvarez; Vivian Brache; Katherine LaGuardia; Harold Nash; Janet Stern

1997-01-01

297

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

298

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

299

Oxidative stress responses in longnose sucker (Catostomus catostomus) exposed to pulp and paper mill and municipal sewage effluents.  

PubMed

While recent evidence indicates that the generation of reactive oxygen species (ROS) and associated oxidative damage are frequently observed in fish populations with exposure to pulp and paper mill effluents, the potential for ROS generation from municipal sewage effluents has not been addressed. This study investigates the utility of measures of oxidative stress in delineating the effects of both pulp and paper mill and municipal sewage discharges. Longnose sucker (Catostomus catostomus) were collected below three pulp and paper mill and two municipal sewage effluent discharges over a 3-year period within the Wapiti and Athabasca River systems in northern Alberta. Biochemical responses in longnose sucker varied between the two rivers systems, with more pronounced changes occurring within the Wapiti River. Of the suite of biochemical parameters examined, fatty acyl-CoA oxidase (FAO) activity was the most sensitive indicator of pulp and paper mill exposure, but was only infrequently induced with exposure to municipal sewage effluent. Hepatic and gonadal 2-thiobarbituric acid reactive substances, lipid hydroperoxides, and hepatic free iron were less consistently elevated with exposure to pulp and paper mill effluent than FAO activity, and were also only infrequently altered with sewage effluent exposure. Hepatic ascorbic acid, liver somatic index, and condition factor were consistently altered with exposure to both sewage and pulp and paper mill effluents. While specific biochemical and organismal responses varied with effluents and time, the collective suite of oxidative stress endpoints proved to be useful tools in identifying relative influences of municipal sewage and pulp and paper mill effluent on fish populations in adjacent receiving waters. PMID:15063075

Oakes, Ken D; McMaster, Mark E; Van Der Kraak, Glen J

2004-04-28

300

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

301

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

302

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

303

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

304

Cosmic Strings Lens Phenomenology Revisited  

Microsoft Academic Search

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

F. Bernardeau

2001-01-01

305

Effects of Chiloquin Dam on spawning distribution and larval emigration of Lost River, shortnose, and Klamath largescale suckers in the Williamson and Sprague Rivers, Oregon  

USGS Publications Warehouse

Chiloquin Dam was constructed in 1914 on the Sprague River near the town of Chiloquin, Oregon. The dam was identified as a barrier that potentially inhibited or prevented the upstream spawning migrations and other movements of endangered Lost River (Deltistes luxatusChasmistes brevirostris) suckers, as well as other fish species. In 2002, the Bureau of Reclamation led a working group that examined several alternatives to improve fish passage at Chiloquin Dam. Ultimately it was decided that dam removal was the best alternative and the dam was removed in the summer of 2008. The U.S. Geological Survey conducted a long-term study on the spawning ecology of Lost River, shortnose, and Klamath largescale suckers (Catostomus snyderi) in the Sprague and lower Williamson Rivers from 2004 to 2010. The objective of this study was to evaluate shifts in spawning distribution following the removal of Chiloquin Dam. Radio telemetry was used in conjunction with larval production data and detections of fish tagged with passive integrated transponders (PIT tags) to evaluate whether dam removal resulted in increased utilization of spawning habitat farther upstream in the Sprague River. Increased densities of drifting larvae were observed at a site in the lower Williamson River after the dam was removed, but no substantial changes occurred upstream of the former dam site. Adult spawning migrations primarily were influenced by water temperature and did not change with the removal of the dam. Emigration of larvae consistently occurred about 3-4 weeks after adults migrated into a section of river. Detections of PIT-tagged fish showed increases in the numbers of all three suckers that migrated upstream of the dam site following removal, but the increases for Lost River and shortnose suckers were relatively small compared to the total number of fish that made a spawning migration in a given season. Increases for Klamath largescale suckers were more substantial. Post-dam removal monitoring only included 2 years with below average river discharge during the spawning season; data from years with higher flows may provide a different perspective on the effects of dam removal on the spawning migrations of the two endangered sucker species.

Martin, Barbara A.; Hewitt, David A.; Ellsworth, Craig M.

2013-01-01

306

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

307

Lumpy cosmic strings  

E-print Network

We outline a model of abelian-Higgs strings with variable scalar and vector core radii. In general, the functions determining the time and position-dependent core widths may be expressed as arbitrary left or right movers, of which the usual constant values are a particular solution. In this case the string may carry momentum, even if the embedding of its central axis remains fixed, and the resulting objects resemble "necklaces". Some possible astrophysical applications of lumpy strings, including as potential engines for anomalous gamma ray bursts, are also discussed.

Matthew J. Lake; Tiberiu Harko

2015-02-16

308

Lumpy cosmic strings  

E-print Network

We outline a model of abelian-Higgs strings with variable scalar and vector core radii. In general, the functions determining the time and position-dependent core widths may be expressed as arbitrary left or right movers, of which the usual constant values are a particular solution. In this case the string may carry momentum, even if the embedding of its central axis remains fixed, and the resulting objects resemble "necklaces". Some possible astrophysical applications of lumpy strings, including as potential engines for anomalous gamma ray bursts, are also discussed.

Lake, Matthew J

2015-01-01

309

Duality, strings and inflation  

SciTech Connect

Arguments based on thermodynamics and on the analysis of string creation effects in expanding spaces suggest the existence of an inflationary phase in the early universe for theories of closed strings. Einstein's equations on the other hand do not support such expectations. The author solves this apparent paradox by noticing that Einstein's equations must be modified at the scale at which this inflationary phase takes place, so that the new equations satisfy the closed string duality principle. Inflation is natural in the context of such modifications and he gives an estimate of the amount of inflation in this early epoch.

Guendelman, E.I. (Weizmann Inst. of Sciences, Rehovot (Israel))

1991-05-01

310

Dissipative string fluids  

NASA Astrophysics Data System (ADS)

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.

Schubring, Daniel

2015-02-01

311

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

312

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

313

String Phenomenology at the LHC  

E-print Network

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 is in the TeV range and the theory is weakly coupled, we review possible signals of string physics at the Large Hadron Collider.

Luis A. Anchordoqui; Haim Goldberg; Dieter Lust; Stephan Stieberger; Tomasz R. Taylor

2010-06-30

314

String Phenomenology at the Lhc  

Microsoft Academic Search

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 is in the TeV range and the theory is weakly coupled, we review possible signals of string physics

Luis A. Anchordoqui; Haim Goldberg; Dieter Lüst; Stephan Stieberger; Tomasz R. Taylor

2009-01-01

315

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

316

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

2005-10-19

317

Mathematics for string phenomenology  

NASA Astrophysics Data System (ADS)

We survey some of the basic mathematical ideas and techniques which are used in string phenomenology, such as constructions of Calabi-Yau manifolds, singularities and orbifolds, toric geometry, variation of complex structure, and mirror symmetry.

Douglas, Michael R.

2015-01-01

318

Mathematics for String Phenomenology  

NASA Astrophysics Data System (ADS)

We survey some of the basic mathematical ideas and techniques which are used in string phenomenology, such as constructions of Calabi-Yau manifolds, singularities and orbifolds, toric geometry, variation of complex structure, and mirror symmetry.

Douglas, Michael R.

2014-12-01

319

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. Conditions are derived for the stationary solutions of the fluid. The requirement of frame invariance restricts second-order corrections to the theory, and is used to calculate the speed of second sound for an idealized cosmic string model.

Daniel Schubring

2015-02-14

320

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

2009-06-23

321

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

322

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

323

Cosmological String Backgrounds  

E-print Network

Talk given at the ``4th Hellenic School on Elementary Particle Physics", Corfu, 2-20 September 1992: The propagation of strings in cosmological space-time backgrounds is reviewed. We show the relation of a special class of cosmological backgrounds to exact conformal field theory. Particular emphasis is put on the singularity structure of the cosmological space-time and on the discrete duality symmetries of the string background.

Dieter Luest

1993-03-31

324

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

325

Dirac equation for strings  

E-print Network

Starting with a Nambu-Goto action, a Dirac-like equation can be constructed by taking the square-root of the momentum constraint. The eigenvalues of the resulting Hamiltonian are real and correspond to masses of the excited string. In particular there are no tachyons. A special case of radial oscillations of a closed string in Minkowski space-time admits exact solutions in terms of wave functions of the harmonic oscillator.

Maciej Trzetrzelewski

2014-11-09

326

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

327

Cosmic strings in gravity  

NASA Astrophysics Data System (ADS)

We consider Kasner-type static, cylindrically symmetric interior string solutions in the theory of modified gravity. The physical properties of the string are described by an anisotropic energy-momentum tensor satisfying the condition ; that is, the energy density of the string along the -axis is equal to minus the string tension. As a first step in our study we obtain the gravitational field equations in the theory for a general static, cylindrically symmetric metric, and then for a Kasner-type metric, in which the metric tensor components have a power law dependence on the radial coordinate . String solutions in two particular modified gravity models are investigated in detail. The first is the so-called "exponential" modified gravity, in which the gravitational action is proportional to the exponential of the sum of the Ricci scalar and matter Lagrangian, and the second is the "self-consistent model", obtained by explicitly determining the gravitational action from the field equations under the assumption of a power law dependent matter Lagrangian. In each case, the thermodynamic parameters of the string, as well as the precise form of the matter Lagrangian, are explicitly obtained.

Harko, Tiberiu; Lake, Matthew J.

2015-02-01

328

Twisted Superconducting Semilocal Strings  

E-print Network

A new class of twisted, current carrying, stationary, straight string solutions having finite energy per unit length is constructed numerically in an extended Abelian Higgs model with global SU(2) symmetry. The new solutions correspond to deformations of the embedded Abrikosov-Nielsen-Olesen (ANO) vortices by a twist -- a relative coordinate dependent phase between the two Higgs fields. The twist induces a global current flowing through the string, and the deformed solutions bifurcate with the ANO vortices in the limit of vanishing current. For each value of the winding number $n=1,2...$ (determining the magnetic flux through the plane orthogonal to the string) there are $n$ distinct, two-parametric families of solutions. One of the continuously varying parameters is the twist, or the corresponding current, the other one can be chosen to be the momentum of the string. For fixed values of the momentum and twist, the $n$ distinct solutions have different energies and can be viewed as a lowest energy ``fundamental'' string and its $n-1$ ``excitations'' characterized by different values of their ``polarization''. The latter is defined as the ratio of the angular momentum of the vortex and its momentum. In their rest frame the twisted vortices have lower energy than the embedded ANO vortices and could be of considerable importance in various physical systems (from condensed matter to cosmic strings).

Peter Forgacs; Sebastien Reuillon; Mikhail S. Volkov

2006-02-17

329

Hydroball string sensing system  

DOEpatents

A hydroball string sensing system for a nuclear reactor that includes stainless tubes positioned to guide hydroball strings into and out of the nuclear reactor core. A sensor such as an ultrasonic transducer transmitter and receiver is positioned outside of the nuclear reactor core and adjacent to the tube. The presence of an object such a bullet member positioned at an end a hydroball string, or any one of the hydroballs interrupts the transmission of ultrasound from the transmitter to the receiver. Alternatively, if the bullet member and hydroballs include a ferritic material, either a Hall effect sensor or other magnetic field sensors such as a magnetic field rate of change sensor can be used to detect the location and position of a hydroball string. Placing two sensors along the tube with a known distance between the sensors enables the velocity of a hydroball string to be determined. This determined velocity can be used to control the flow rate of a fluid within the tube so as to control the velocity of the hydroball string.

Hurwitz, Michael J. (Pittsburgh, PA); Ekeroth, Douglas E. (Delmont, PA); Squarer, David (Pittsburgh, PA)

1991-01-01

330

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  

SciTech Connect

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.

Munkittrick, K.R.; Miller, P.A.; Barton, D.R.; Dixon, D.G. (University of Waterloo, Ontario (Canada))

1991-06-01

331

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

332

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

333

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

334

Comparison of different models to predict the in situ embryonic developmental rate of fish, with special reference to white sucker ( Catostomus commersoni )  

Microsoft Academic Search

We performed laboratory incubations of white sucker (Catostomus commersoni) eggs to determine (i) the incubation time to organogenesis, eyed egg, hatching, and swim-up phases at eight different temperatures (8.5ñ21.2?C), and (ii) the best model to describe the relationship between these incubation times and temperature. Seven models (degree-day, power-law, BelehrÆdekís equation, quadratic equation, first- and second-order exponentials, and a thermodynamic model)

Patrice Hamel; P. Magnan; P. East; M. Lapointe; P. Laurendeau

1997-01-01

335

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

336

Exposure of fish to biologically treated bleached-kraft effluent; 1: Biochemical, physiological and pathological assessment of Rocky Mountain whitefish (Prosopium williamsoni) and longnose sucker (Catostomus catostomus)  

Microsoft Academic Search

A suite of biochemical, physiological, and pathological measures was used to assess possible effects of exposure to bleached-kraft mill effluent (BKME) on wild longnose sucker (Catostomus catostomus=LS) and mountain whitefish (Prosopium williamsoni=MW) in the Wapiti\\/Smoke River system, as compared to similar populations in a reference river system without BKME inputs. Individual fish body burden data were examined for correlations between

P. J. Kloepper-Sams; J. W. Owens; S. M. Swanson; T. Marchant; R. Schryer

1994-01-01

337

Influence of habitat dynamics on the distribution and abundance of the federally threatened Santa Ana Sucker, Catostomus santaanae , in the Santa Ana River  

Microsoft Academic Search

Habitat degradation affects native stream fish populations worldwide. We examined the impact of fluctuation in environmental\\u000a variables on the population dynamics of the federally threatened Santa Ana sucker, Catostomus santaanae, in the Santa Ana River, California through: 1) annual quantitative surveys of C. santaanae abundance and habitat at three 100-m sites between 2001 and 2008 and 2) annual surveys of

Andrew Richard Thompson; Jonathan N. Baskin; Camm C. Swift; Thomas R. Haglund; Randall J. Nagel

2010-01-01

338

Regulation of protein kinase C and ornithine decarboxylase in the epidermis of juvenile white suckers ( Catostomus commersoni) by 12-O-tetradecanoylphorbol-13-acetate, 17 ?-ethinylestradiol and testosterone  

Microsoft Academic Search

This study was designed to investigate whether potent regulators of mammalian protein kinase C (PKC) and ornithine decarboxylase (ODC) activity also regulate epidermal PKC and ODC activity in fish. Juvenile white suckers (Catostomus commersoni) were given single or multiple subdermal injections of testosterone, 17?-ethinylestradiol or 12-O-tetradeconylphorbol-13-acetate (TPA) dissolved in sunflower oil. Sequential activation of epidermal PKC and ODC was observed

Peter D. Premdas; Chris D. Metcalfe

1996-01-01

339

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

340

High temperature control rod assembly  

DOEpatents

A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

Vollman, Russell E. (Solana Beach, CA)

1991-01-01

341

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

342

Investigating Fraction Relationships with Relationship Rods  

NSDL National Science Digital Library

In this lesson plan from Illuminations, students use relationship rods to explore fraction relationships. Relationship rods range in length from one to ten centimeters, and each rod is a different color. An activity sheet with solutions, questions for students, assessment options, and suggested extension activities are included. The lesson plan is part of a five lesson plan unit, Fun with Fractions, which is cataloged separately.

Tracy Y. Hargrove

2012-01-01

343

Automatic safety rod for reactors. [LMFBR  

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-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, J.H.

1982-03-23

344

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

345

K.CC Number Rods  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials * Unifix cubes or snap cubes, composed into rods with 1-10 cubes (or any counting sequence the class is currently working on within 20) If th...

2012-10-01

346

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

347

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

348

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

2007-03-05

349

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

350

A Generalized Piezoelectric Bernoulli–Navier Anisotropic Rod Model  

Microsoft Academic Search

We apply the asymptotic analysis procedure to the three-dimensional static equations of piezoelectricity, for a linear nonhomogeneous anisotropic thin rod. We prove the weak convergence of the rod mechanical displacement vectors and the rod electric potentials, when the diameter of the rod cross-section tends to zero. This weak limit is the solution of a new piezoelectric anisotropic nonhomogeneous rod model,

Isabel M. Narra Figueiredo; Carlos M. Franco Leal

2006-01-01

351

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

352

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

NASA Astrophysics Data System (ADS)

We compute, via numerical simulations, the nonperturbative Coulomb potential of pure SU(3) gauge theory in Coulomb gauge. We find 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

353

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

354

Topics in String Theory.  

NASA Astrophysics Data System (ADS)

We will discuss several aspects of string theory. First, we will calculate the vacuum amplitude of un-oriented open and closed string theory using Polyakov formalism. We argue that the volume of the Mobius Group should be renormalized, and solve a minor paradox. Second, we will give an example of a membrane whose effective action is the generalization of Green-Schwarz covariant superstring action. As a by -product, we show that it also provides an example of partially broken global supersymmetry. The rest of the dissertation will be devoted to the study of string field theory in terms of the renormalization group approach. We emphasize the pivotal role of the conformal invariance in string theory. We propose the generalized Wilsonian conformal renormalization group equation of 2-dimensional quantum field theory as the field equation for string field theory following Banks and Martinec. We then find general solutions to the linearized equation on the flat background and its correspondence to all the physical vertex operators. We also make detailed study of massless modes and offer some remarks about how gauge invariance arise in this approach. Finally, we solve the full nonlinear equation iteratively in terms of the solutions to the linearized equation and extract the Virasoro-Shapiro amplitudes from them.

Liu, Jun

355

Space from String Bits  

E-print Network

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. Letting each string bit be an adjoint of a "color" group U(N), we then analyze the physics of 't Hooft's limit $N->\\infty$, 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 $\\theta_{L,R}^a$, 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 $-1\\pm 1$, in which $R_k->\\infty$. As noted in earlier work [Phys.Rev.D{\\bf 89}(2014)105002], these multi-string-bit chains are strictly stable at $N=\\infty$ when d

Charles B. Thorn

2014-08-28

356

M-Strings  

NASA Astrophysics Data System (ADS)

M2 branes suspended between adjacent parallel M5 branes lead to light strings, the `M-strings'. In this paper we compute the elliptic genus of M-strings, twisted by maximally allowed symmetries that preserve 2 d (2, 0) supersymmetry. In a codimension one subspace of parameters this reduces to the elliptic genus of the (4, 4) supersymmetric A n-1 quiver theory in 2 d. We contrast the elliptic genus of N M-strings with the (4, 4) sigma model on the N-fold symmetric product of . For N = 1 they are the same, but for N > 1 they are close, but not identical. Instead the elliptic genus of (4, 4) N M-strings is the same as the elliptic genus of (4, 0) sigma models on the N-fold symmetric product of , but where the right-moving fermions couple to a modification of the tangent bundle. This construction arises from a dual A n-1 quiver 6 d gauge theory with U(1) gauge groups. Moreover, we compute the elliptic genus of domain walls which separate different numbers of M2 branes on the two sides of the wall.

Haghighat, Babak; Iqbal, Amer; Kozçaz, Can; Lockhart, Guglielmo; Vafa, Cumrun

2015-03-01

357

Topics on String Phenomenology  

E-print Network

These lectures present some topics of string phenomenology and contain two parts. In the first part, I review the possibility of lowering the string scale in the TeV region, that provides a theoretical framework for solving the mass hierarchy problem and unifying all interactions. The apparent weakness of gravity can then be accounted by the existence of large internal dimensions, in the submillimeter region, and transverse to a braneworld where our universe must be confined. I review the main properties of this scenario and its implications for observations at both particle colliders, and in non-accelerator gravity experiments. In the second part, I discuss a simple framework of toroidal string models with magnetized branes, that offers an interesting self-consistent setup for string phenomenology. I will present an algorithm for fixing the geometric parameters of the compactification, build calculable particle physics models such as a supersymmetric SU(5) Grand Unified Theory with three generations of quarks and leptons, and implement low energy supersymmetry breaking with gauge mediation that can be studied directly at the string level.

I. Antoniadis

2007-11-08

358

Ghost Structure and Closed Strings in Vacuum String Field Theory  

Microsoft Academic Search

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

Davide Gaiotto; Leonardo Rastelli; Ashoke Sen; Barton Zwiebach

2001-01-01

359

N-string vertices in string field theory  

Microsoft Academic Search

We give the general form of the vertex corresponding to the interaction of an arbitrary number of strings. The technique employed relies on the ``comma'' representation of string field theory where string fields and interactions are represented as matrices and operations between them such as multiplication and trace. The general formulation presented here shows that the interaction vertex of N

J. Bordes; A. Abdurrahman; F. Antón

1994-01-01

360

Half-string oscillator approach to string field theory  

Microsoft Academic Search

We give an operator formulation of the string field theory proposed by E. Witten using half-string oscillator modes. This formalism, identifying the physical string states as infinite matrices, is developed in such a way that interactions at the level of vertices can be calculated in terms of products and traces of these matrices without relying on ill-defined manipulations of functional

J. Bordes; Chan Hong-Mo; Lukas Nellen; Sheung Tsou Tsun

1991-01-01

361

Solution to Practice Problems: String Problems  

E-print Network

at the end of each of these programs. public class String-Assignments { public static void main(String; } } "you" ? s null t u v "me" w "youme" #12;public class String-Commands { public static void main(String is an example that removes a portion of a String, // and inserts a replacement public class String

Yates, Alexander

362

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

363

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

364

Assessing genetic diversity of wild and hatchery samples of the Chinese sucker (Myxocyprinus asiaticus) by the mitochondrial DNA control region.  

PubMed

Abstract To restore the natural populations of Chinese sucker (Myxocyprinus asiaticus), a hatchery release program has been underway for nearly 10 years. Using DNA sequences of the mitochondrial control region, we assessed the genetic diversity and genetic structure among samples collected from three sites of the wild population as well as from three hatcheries. The haplotype diversity of the wild samples (h?=?0.899-0.975) was significantly higher than that of the hatchery ones (h?=?0.296-0.666), but the nucleotide diversity was almost identical between them (??=?0.0170-0.0280). Relatively high gene flow was detected between the hatchery and wild samples. Analysis of effective population size indicated that M. asiaticus living in the Yangtze River has been expanding following a bottleneck in the recent past. Our results suggest the hatchery release programs for M. asiaticus have not reduced the genetic diversity, but have influenced the genetic structure of the species in the upper Yangtze River. PMID:25242190

Wu, Jiayun; Wu, Bo; Hou, Feixia; Chen, Yongbai; Li, Chong; Song, Zhaobin

2014-09-22

365

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

PubMed

17alpha-ethynylestradiol (EE2), a synthetic estrogen prescribed as a contraceptive, was measured in Shorthead Redhorse Suckers (ShRHSs) (Moxostoma macrolepidotum) collected near a wastewater treatment plant (WWTP) in the St. Clair River (Ontario, Canada). We detected EE2 in 50% of the fish samples caught near the WWTP (Stag Island), which averaged 1.6+/-0.6ng/g (wet weight) in males and 1.43+/-0.96ng/g in females. No EE2 was detected in the samples from the reference site (Port Lambton) which was 26km further downstream of the Stag Island site. Only males from Stag Island had VTG induction, suggesting the Corunna WWTP effluent as a likely source of environmental estrogen. EE2 concentrations were correlated with total body lipid content (R(2)=0.512, p<0.01, n=10). Lipid normalized EE2 concentrations were correlated with delta(15)N (R(2)=0.436, p<0.05, n=10), suggesting higher EE2 exposures in carnivores. Our data support the hypothesis of EE2 bioaccumulation in wild fish. PMID:20561724

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

2010-08-01

366

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

367

Trampling, defoliation and physiological integration affect growth, morphological and mechanical properties of a root-suckering clonal tree  

PubMed Central

Background and Aims Grazing is a complex process involving the simultaneous occurrence of both trampling and defoliation. Clonal plants are a common feature of heavily grazed ecosystems where large herbivores inflict the simultaneous pressures of trampling and defoliation on the vegetation. We test the hypothesis that physiological integration (resource sharing between interconnected ramets) may help plants to deal with the interactive effects of trampling and defoliation. Methods In a field study, small and large ramets of the root-suckering clonal tree Populus simonii were subjected to two levels of trampling and defoliation, while connected or disconnected to other ramets. Plant responses were quantified via survival, growth, morphological and stem mechanical traits. Key Results Disconnection and trampling increased mortality, especially in small ramets. Trampling increased stem length, basal diameter, fibrous root mass, stem stiffness and resistance to deflection in connected ramets, but decreased them in disconnected ones. Trampling decreased vertical height more in disconnected than in connected ramets, and reduced stem mass in disconnected ramets but not in connected ramets. Defoliation reduced basal diameter, leaf mass, stem mass and leaf area ratio, but did not interact with trampling or disconnection. Conclusions Although clonal integration did not influence defoliation response, it did alleviate the effects of trampling. We suggest that by facilitating resource transport between ramets, clonal integration compensates for trampling-induced damage to fine roots. PMID:22314757

Xu, Liang; Yu, Fei-Hai; van Drunen, Elles; Schieving, Feike; Dong, Ming; Anten, Niels P. R.

2012-01-01

368

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.

2004-02-20

369

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

2005-11-10

370

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

2007-04-05

371

Shunting arc generation by parallel rod configuration  

NASA Astrophysics Data System (ADS)

Multi-shunting arc discharges were generated using carbon rods to deposit a carbon film on a silicon substrate. Two carbon rods of 2 mm diameter and 40 mm length were set between electrodes in parallel to generate multiple carbon plasmas. The pulse current was supplied from a 20 µF capacitor bank to evaporate the surface of the rods through a Joule heating process. Repetitive pulse voltages of -1 kV were applied to the disk electrode to extract the carbon ion from the plasmas and to deposit a carbon film. The rod current for both rods shows almost the same value before shunting arc ignition. The shunting arc was generated at 5-10 µs after the release of energy stored in the capacitor bank. The shunting arc current was controlled successfully by inserting an inductor in series to the rod. The ion current was changed by the position of the disk electrode owing to the difference in the arc current for each rod. The deposition rate of the carbon film on the silicon substrate also showed a difference with the position of the substrate. The spatial profile of the deposition rate was controlled by the inductance of each rod branch.

Takaki, T.; Murakami, T.; Mukaigawa, S.; Fujiwara, T.; Yukimura, K.

2011-02-01

372

Vertical close pack rod arraying system  

Microsoft Academic Search

A rod arraying system is described comprising: (a) a rigid support structure; (b) a canister positioned in and supported by the support structure; (c) a mounting base slidably attached to the support structure on an incline; (d) a guide assembly attached to the mounting base for positioning rods inside the canister. The system consists of: (i) an upper guide plate

D. J. Attix; M. J. Kelly; F. L. Mason; C. E. Stinnett

1989-01-01

373

Rod seal device for Stirling engines  

Microsoft Academic Search

A rod seal device for a Stirling engine is described which consists of: a piston rod having a first end connected to an operating piston for the engine and a second end connected to a guide piston disposed in a crank case; a compression chamber defined by the operating piston and a cylinder of the engine and including a working

D. Kobayashi; T. Itaba; Y. Momose

1987-01-01

374

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

375

Dimensional reduction of a piezoelectric composite rod  

Microsoft Academic Search

In the present paper, a new generalized Timoshenko model is constructed for a composite rod with embedded or attached piezoelectric materials. This model is applicable to composite rods without prescribed electric potential along the lateral surfaces. The Variational-Asymptotic Method (VAM) is applied as a mathematical tool to carry out the dimensional reduction process. The present reduced model captured the effects

Sitikantha Roy; Wenbin Yu

2009-01-01

376

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

377

CONTROL ROD DRIVE MECHANISM ON THE EBWR  

Microsoft Academic Search

The control rod drive mechanlsms installed on the Argonne Experimental ; Boiling Water Reactor (EBWR) are of an externally operated lead screw and nut ; type in which the control rod extension shafts are driven through pressure ; breakdown, collected leakage seals. The mechanisms which are located below the ; reactor are fabricated from conventional industrial materials, such as carbon

Bullinger; C. F. f Kann

1958-01-01

378

Topological optimisation of rod-stirring devices  

Microsoft Academic Search

There are many industrial situations where rods are used to stir a fluid, or where rods repeatedly stretch a material such as bread dough or taffy. The goal in these applications is to stretch either material lines (in a fluid) or the material itself (for dough or taffy) as rapidly as possible. The growth rate of material lines is conveniently

Matthew D. Finn; Jean-Luc Thiffeault

2010-01-01

379

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

380

Fuzzy Ultrasonic Testing System with Columnar Rod  

Microsoft Academic Search

This paper describes an ultrasonic testing system with a columnar rod. The general ultrasonic probe is affected by transmission pulse for measurement using the direct contact method. However, if we use a columnar rod between an ultrasonic probe and a target object, we can measure without the transmission pulse. This paper describes the measurement system of the object thickness by

J. Yasui; S. Kobashi; K. Kondo; Y. Hata

2006-01-01

381

Wormholes in String Theory  

E-print Network

A wormhole is constructed by cutting and joining two spacetimes satisfying the low energy string equations with a dilaton field. In spacetimes described by the "string metric" the dilaton energy-momentum tensor need not satisfy the weak or dominant energy conditions. In the cases considered here the dilaton field violates these energy conditions and is the source of the exotic matter required to maintain the wormhole. There is also a surface stress-energy, that must be produced by additional matter, where the spacetimes are joined. It is shown that wormholes can be constructed for which this additional matter satisfies the weak and dominant energy conditions, so that it could be a form of "normal" matter. Charged dilaton wormholes with a coupling between the dilaton and the electromagnetic field that is more general than in string theory are also briefly discussed.

Dan N. Vollick

1998-06-24

382

Quantum String Theory  

NASA Astrophysics Data System (ADS)

String theories seem to have created a breakthrough in theoretical physics. At long last a unified theory of all the fundamental interactions, including gravity, looks possible. This, according to theorist Stephen Hawking, will mark the end of theoretical physics as we have known it, since we will then have a single consistent theory within which to explain all natural phenomena from elementary particles to galactic superclusters. Strings themselves are extremely tiny entities, smaller than the Planck scale, which form loops whose vibrational harmonics can be used to model all the standard elementary particles. Of course the mathematical complexities of the theory are daunting, and physicists are still at a very early stage in understanding how strings and their theoretical cousins superstrings can be used. This proceedings volume gives an overview of the intense recent work in the field and reports latest developments.

Kawamoto, Noboru; Kugo, Taichiro

383

String radiative backreaction  

SciTech Connect

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

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

1995-12-01

384

Strings on Bubbling Geometries  

E-print Network

We study gauge theory operators which take the form of a product of a trace with a Schur polynomial, and their string theory duals. These states represent strings excited on bubbling AdS geometries which are dual to the Schur polynomials. These geometries generically take the form of multiple annuli in the phase space plane. We study the coherent state wavefunction of the lattice, which labels the trace part of the operator, for a general Young tableau and their dual description on the droplet plane with a general concentric ring pattern. In addition we identify a density matrix over the coherent states on all the geometries within a fixed constraint. This density matrix may be used to calculate the entropy of a given ensemble of operators. We finally recover the BMN string spectrum along the geodesic near any circle from the ansatz of the coherent state wavefunction.

Hai Lin; Alexander Morisse; Jonathan P. Shock

2011-07-27

385

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.

Brax, Philippe; Davis, Anne-Christine; Davis, Stephen C; Jeannerot, Rachel; Postma, Marieke

2008-01-01

386

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

387

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

388

Quantum vortex strings: A review  

Microsoft Academic Search

The quantum worldsheet dynamics of vortex strings contains information about the 4d non-Abelian gauge theory in which the string lives. Here I tell this story. The string worldsheet theory is typically some variant of the CPN-1 sigma-model, describing the orientation of the string in a U(N) gauge group. Qualitative parallels between 2d sigma-models and 4d non-Abelian gauge theories have been

David Tong

2009-01-01

389

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

390

Embellished String Prints. Cover Story.  

ERIC Educational Resources Information Center

Focuses on a printmaking activity in which students create embellished string prints using the relief process of string glued to chip board. Explains that string prints can easily be embellished with oil pastels. Provides a description of the procedure and a list of materials and methods. (CMK)

Smith, Mary Ruth

1999-01-01

391

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

392

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

393

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

394

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

395

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

396

Black holes in string theory  

Microsoft Academic Search

The field equations, which emerge from string theory, are solved to leading order in alpha' for the case of black hole space-times. We show how the results fit into a broader outlook on string theory and quantum gravity. In particular, it seems that string theory could cure some of the paradoxes associated with black hole evaporation. Supported by The Royal

C. G. Callan; R. C. Myers; M. J. Perry

1989-01-01

397

Black Holes in String Theory  

Microsoft Academic Search

The black hole solutions to Einstein's vacuum field equations are also solutions to the equations of motion of the low energy limit of superstring theory. At the same time, string theory boasts a much broader and richer collection of black hole solutions. Fortunately, string theories also possess a remarkable set of duality symmetries relating states within and between different string

J. C. Breckenridge

1997-01-01

398

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

2014-12-20

399

The second string (phenomenology) revolution  

Microsoft Academic Search

Over the past three years our views on how the standard model of particle theory could be embedded into string theory have changed dramatically. 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 II strings, now seem possible. It has also been realized that

Luis E. Ibáñez

2000-01-01

400

Adventures in heterotic string phenomenology  

Microsoft Academic Search

In this Dissertation, we consider three topics in the study of effective field theories derived from orbifold compactifications of the heterotic string. In Chapter 2 we provide a primer for those interested in building models based on orbifold compactifications of the heterotic string. In Chapter 3, we analyze gauge coupling unification in the context of heterotic strings on anisotropic orbifolds.

George Benjamin Dundee

2010-01-01

401

Particle, Strings & aka Particle Theory  

E-print Network

/cosmology Applied String Theory Math Dept CMT Particle Phenomenology Exp. Particle Physics Friday, November 21, 14Particle, Strings & Fields aka Particle Theory Steve Ellis (Emeritus) Andreas Karch Ann Nelson (Yaffe): studying quark-gluon plasma using "applied string theory" Akshay Ghalsasi (Nelson): cosmological

Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

402

NEUTRINOS FROM STRINGS:. A Practical Introduction to String Theory, String Model-Building, and String Phenomenology -- Part I: Ten Dimensions  

Microsoft Academic Search

This is the written version of an introductory self-contained course on string model-building and string phenomenology given at the 1998 TASI summer school. No prior knowledge of string theory is assumed. The goal is to provide a practical, \\

Keith R. Dienes

2000-01-01

403

Drill string shock absorber  

SciTech Connect

A telescopic shock absorber for use in a drill string includes a resilient arrangement to cushion telescopic contraction and extension of the shock absorber in response to shock loads and vibrations imparted during drilling. The shock absorber operates independently of the drilling fluid pressure conducted through the structure during drilling operations. A dampening system assists in cushioning the shock loads and vibrations and the dampening system and resilient arrangement are deactivated when jarring impacts are delivered to the well string by a drilling jar carried therein. The resilient arrangement provides a combination mechanical and hydraulic system for cushioning the impact loads and vibrations encountered.

Anderson, E. A.; Webb, D. D.

1985-11-12

404

Quantum string cosmologies  

NASA Astrophysics Data System (ADS)

Different models of quantum string minisuperspaces for both isotropic and anisotropic geometries are presented. As for the isotropic case the general model of axion-dilaton cosmology of arbitrary curvature is studied and solved explicitly. In the anisotropic case Bianchi type I and IX and Kantowski-Sachs geometries are investigated. A short review of string cosmology is given with the emphasis on its graceful-exit problem. The problems of boundary conditions, wave packets in minisuperspace and possible implications for the arrow of time in cosmology are briefly discussed.

Dbrowski, Mariusz P.

2001-03-01

405

Probing the String Landscape  

ScienceCinema

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

Keith Dienes

2010-01-08

406

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

407

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

2010-05-17

408

Superconducting cosmic strings  

NASA Astrophysics Data System (ADS)

Superconducting cosmic strings produce a variety of effects, such as spectral distortion of the cosmic microwave background (CMB), early reionization, linearly polarized radio transients and ultra high energy cosmic ray bursts, in addition to the well known gravitational wave signals and CMB anisotropies. I will argue that these effects can be seen in the CMB distortion (PIXIE), radio transient experiments (LOFAR, SKA) and at the future neutrino telescopes (JEM-EUSO, LOFAR, SKA), and can be complimentary to the gravitational wave experiments (LIGO, eLISA) and CMB anisotropy observations. If none of these effects are seen within a few years, very stringent constraints can be put on superconducting cosmic strings.

Sabancilar, Eray

2013-10-01

409

New Developments in String Gravity and String Cosmology.A Summary Report  

E-print Network

New Developments in String Gravity and String Cosmology are reported: 1-String driven cosmology and its Predictions. 2-The primordial gravitational wave background in string cosmology. 3-Non-singular string cosmologies from Exact Conformal Field Theories. 4-Quantum Field Theory, String Temperature and the String Phase of de Sitter space-time, 5-Hawking Radiation in String Theory and the String Phase of Black Holes. 6-New Dual Relation between Quantum Field Theory regimes and String regimes in Curved Backgrounds, and the 'QFT/String Tango'. 7- New Coherent String States and Minimal Uncertainty Principle in WZWN models

Norma G. Sanchez

2002-09-02

410

Number of cosmic string loops  

NASA Astrophysics Data System (ADS)

Using recent simulation results, we provide the mass and speed spectrum of cosmic string loops. This is the quantity of primary interest for many phenomenological signatures of cosmic strings, and it can be accurately predicted using recently acquired detailed knowledge of the loop production function. We emphasize that gravitational smoothing of long strings plays a negligible role in determining the total number of existing loops. We derive a bound on the string tension imposed by recent constraints on the stochastic gravitational wave background from pulsar timing arrays, finding G? ?2.8×10-9. We also provide a derivation of the Boltzmann equation for cosmic string loops in the language of differential forms.

Blanco-Pillado, Jose J.; Olum, Ken D.; Shlaer, Benjamin

2014-01-01

411

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

412

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

413

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

414

Chaos in String Cosmology  

NASA Astrophysics Data System (ADS)

We briefly review recent work which established the existence of chaos in the generic cosmological solutions of the tree-level low-energy effective actions coming out of string theory, and linked this chaos to the Weyl groups of some hyperbolic Kac-Moody algebras.

Damour, Thibault

415

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

416

Wing on a String  

ERIC Educational Resources Information Center

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

Fitzgerald, Mike; Brand, Lance

2004-01-01

417

Cosmic string loop microlensing  

NASA Astrophysics Data System (ADS)

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

Bloomfield, Jolyon K.; Chernoff, David F.

2014-06-01

418

Aspects of String Phenomenology  

Microsoft Academic Search

Lowering the string scale in the TeV region provides a theoretical framework for solving the mass hierarchy problem and unifying all interactions. The apparent weakness of gravity can then be accounted by the existence of large internal dimensions, in the submillimeter region, and transverse to a braneworld where our universe must be confined. I review the main properties of this

I. Antoniadis

2010-01-01

419

The song of the singing rod.  

PubMed

This paper discusses basic and advanced aspects of the sound radiated by the singing rod demonstration commonly used in physics courses to depict an example of longitudinal waves. Various methods of exciting these rods are discussed along with the issues associated with each method. Analysis of the sound radiated by various rods with small-signal and large-signal excitations is presented for four different rods. The small-signal sound radiation consists of a fundamental frequency and odd harmonics (each corresponding to a longitudinal mode) when the rod is held at its midpoint. Large-signal sound radiation is highly dependent on the rod's geometry. The large-signal sound can possess strong even harmonics and/or beating tones resulting from modal coupling of transverse bending modes and either subharmonic longitudinal modes or torsional modes. A detailed analysis of the sound radiation from a singing rod can provide excellent laboratory exercises or classroom demonstrations for advanced undergraduate or graduate level acoustics courses whose scope includes resonances of a bar. PMID:22423791

Anderson, Brian E; Peterson, Wayne D

2012-03-01

420

Strings in homogeneous background spacetimes  

NASA Astrophysics Data System (ADS)

The string equations of motion for some homogeneous (Kantowski-Sachs, Bianchi type I and Bianchi type IX) background spacetimes are given, and solved explicitly in some simple cases. This is motivated by the recent developments in string cosmology, where it has been shown that, under certain circumstances, such spacetimes appear as string vacua. Both tensile and null strings are considered. Generally, it is much simpler to solve for the null strings since then we deal with the null geodesic equations of general relativity plus some additional constraints. We consider in detail an Ansatz corresponding to circular strings, and we discuss the possibility of using an elliptic-shape string Ansatz in the case of homogeneous (but anisotropic) backgrounds.

Dabrowski, Mariusz P.; Larsen, Arne L.

1998-04-01

421

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

422

Rod seal device for Stirling engines  

SciTech Connect

A rod seal device for a Stirling engine is described which consists of: a piston rod having a first end connected to an operating piston for the engine and a second end connected to a guide piston disposed in a crank case; a compression chamber defined by the operating piston and a cylinder of the engine and including a working gas for the engine; a first intermediate chamber surrounding an outer periphery of the piston rod and being connected to the compression chamber and kept to maintain a minimum level of pressure of the working gas; a high pressure oil chamber disposed next to the first intermediate chamber and surrounding the outer periphery of the piston rod. A first low pressure oil chamber disposed next to the high pressure oil chamber via an oil seal member and surrounding the outer periphery of the piston rod. A first scraper seal disposed next to the first low pressure oil chamber and surrounding the outer periphery of the piston rod; a second intermediate chamber disposed next to the first low pressure oil chamber via the first scraper seal and surrounding the outer periphery of the piston rod; a second scraper seal disposed next to the second intermediate chamber and surrounding the outer periphery of the piston rod; a second low pressure oil chamber disposed next to the second intermediate chamber via the second scraper seal and surrounding the outer periphery of the piston rod, a second oil pump disposed between the second low pressure oil chamber and the second low pressure oil reservoir to positively discharge any gas introduced into the second low pressure oil chamber to the atmosphere; and a further oil seal disposed between the second low pressure oil chamber and a working gas chamber in the crank use for a power take-off device.

Kobayashi, D.; Itaba, T.; Momose, Y.

1987-09-22

423

Nanopipes in gallium nitride nanowires and rods.  

PubMed

Gallium nitride nanowires and rods synthesized by a catalyst-free vapor-solid growth method were analyzed with cross section high-resolution transmission electron microscopy. The cross section studies revealed hollow core screw dislocations, or nanopipes, in the nanowires and rods. The hollow cores were located at or near the center of the nanowires and rods, along the axis of a screw dislocation. The formation of the hollow cores is consistent with effect of screw dislocations with giant Burgers vector predicted by Frank. PMID:19367802

Jacobs, Benjamin W; Crimp, Martin A; McElroy, Kaylee; Ayres, Virginia M

2008-12-01

424

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

425

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

426

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

427

Simulation studies of self-assembly of end-tethered nanorods in solution and role of rod aspect ratio and tether length  

NASA Astrophysics Data System (ADS)

We present temperature versus concentration phase diagrams for "shape amphiphiles" comprised of tethered moderate and low aspect ratio rods. Simulations of moderate aspect ratio rods (first reported by Horsch et al. [Phys. Rev. Lett. 95, 056105 (2005)]) predict their self-assembly into spherical micelles with bcc order, long micelles with nematic order, a racemic mixture of hexagonally ordered chiral cylinders, two perforated phases: one with tetragonal order and one with hexagonal order, and a smectic C lamellar phase. In contrast, we predict here that small aspect ratio tethered rods self-assemble into bcc ordered spherical micelles, hexagonally ordered cylinders, and a smectic C lamellar phase. We compare and contrast the phases obtained for the two aspect ratios and examine in further detail several unusual phases. Our simulations also reveal that for moderate aspect ratio rods there is a tendency toward phases with decreasing interfacial curvature with decreasing coil size, including a double gyroid phase. In addition, we investigate the role of tether length on the assembled structures. Our results are applicable to short rod-coil block copolymers and rodlike nanoparticles with polymer tethers, and to colloidal building blocks comprised of a flexible string of colloids tethered to a rigid string of colloids, with the interactions scaled appropriately.

Horsch, Mark A.; Zhang, Zhenli; Glotzer, Sharon C.

2006-11-01

428

Dimensional Reduction of a Piezoelectric Composite Rod  

E-print Network

is asymptotically approximated by VAM using the slenderness of the rod as the small parameter and subsequently. As an alter- native, researchers try to exploit the slender nature of beam like structures and simplify

Yu, Wenbin

429

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

430

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 toward ...

Khalid Jawed, Mohammad

431

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

432

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

433

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

SciTech Connect

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., E-mail: vejitarev@nnrd.kiae.su; Kachanov, V. M.; Sergevnin, A. Yu.; Lebedev, G. V., E-mail: lgv2004@mail.ru [National Research Center Kurchatov Institute (Russian Federation)

2014-12-15

434

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

435

Quenching studies on a zircaloy rod bundle  

Microsoft Academic Search

Quenching data are presented for reflooding by cold water of zircaloy and stainless steel clad rod bundles. In particular a filling material (AlâOâ) with thermophysical properties similar to UOâ is used. The rods which are 1.1 mm in outside diameter and are 1.2 m high are arranged in a square lattice and are inductively heated. The experiments have been performed

V. K. Dhir; R. B. Duffey; I. Catton

1981-01-01

436

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

437

Making Crystal Filaments From Extruded Ceramic Rods  

NASA Technical Reports Server (NTRS)

New process produces single-crystal fibers of ceramic or metal at lower cost. Single-crystal filament drawn from tip of extruded polycrystalline rod. Extrusion produces longer rods from which longer fibers drawn. Potentially feeds single fiber drawing process directly. Continuous filaments made, and material not subjected to contamination from storage and transfer to drawing machine. Filaments used as reinforcing fibers in composite materials.

Westfall, Leonard J.

1992-01-01

438

Scalable diode array pumped Nd rod laser  

NASA Technical Reports Server (NTRS)

Experiments were carried out on a five-array pump head which utilizes gold-coated reflective cones to couple the pump energy to Nd:YAG and Nd:YLF rod lasers, demonstrating high efficiency and uniform energy deposition. Because the cones function as optical diodes to light outside their acceptance angle (typically 10-15 deg), much of the diode energy not absorbed on the first pass can be returned to the rod.

Zenzie, H. H.; Knights, M. G.; Mosto, J. R.; Chicklis, E. P.; Perkins, P. E.

1991-01-01

439

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

440

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

441

Correspondence of Z2-orbifold string and torus string  

NASA Astrophysics Data System (ADS)

We investigate the correspondence between a Z2 orbifold string and a torus string model which have the same vacuum amplitudes when they take particular radii. We show that ground states of the twisted sector of Z2 orbifold can be easily described by the torus string. In our formalism, we obtain the same amplitudes as those of Hamidi and Vafa, and of Dixon, Friedan, Martinec, and Shenker.

Kobayashi, K.

1987-06-01

442

pp-wave string interactions from the string bit model  

Microsoft Academic Search

We construct the string states |OJp>J, |OJ1q>J1J2, and |OJ1J20>J1J2 in the Hilbert space of the quantum mechanical orbifold model so as to calculate the three-point functions and the matrix elements of the light-cone Hamiltonian from the interacting string bit model. With these string states we show that the three-point functions and the matrix elements of the Hamiltonian derived from the

Jian-Ge Zhou

2003-01-01

443

Long-Rod Moving-Plate Interaction  

NASA Astrophysics Data System (ADS)

Understanding the mechanics of interaction of a long rod projectile with a forward moving plate at an angle is essential to understanding long rod interaction with an explosive reactive armor cassette. To investigate the mechanics of such an interaction we use AUTODIN2D/EULER in plane geometry, although the problem is 3D. We assume that this is a satisfactory approximation, as we're only interested in the main features, and are not comparing fine details to experimental results. From the simulations we learn that the interaction never reaches steady state. Initially each material splits into two streams, and the interaction plane is perpendicular to the rod. But with time the interaction plane rotates slowly, until it becomes parallel to the rod, which is then able to continue moving forward without interruption. During this process interacting rod material of length DeltaL is diverted at an angle and becomes ineffective for penetrating the main target. We made many such runs to determine the dependence of DeltaL on the parameters of the problem. This dependence makes it possible to predict DeltaL for a variety of rod-plate situations.

Partom, Y.

2002-07-01

444

Topological optimisation of rod-stirring devices  

E-print Network

There are many industrial situations where rods are used to stir a fluid, or where rods repeatedly stretch a material such as bread dough or taffy. The goal in these applications is to stretch either material lines (in a fluid) or the material itself (for dough or taffy) as rapidly as possible. The growth rate of material lines is conveniently given by the topological entropy of the rod motion. We discuss the problem of optimising such rod devices from a topological viewpoint. We express rod motions in terms of generators of the braid group, and assign a cost based on the minimum number of generators needed to write the braid. We show that for one cost function -- the topological entropy per generator -- the optimal growth rate is the logarithm of the golden ratio. For a more realistic cost function,involving the topological entropy per operation where rods are allowed to move together, the optimal growth rate is the logarithm of the silver ratio, $1+\\sqrt{2}$. We show how to construct devices that realise th...

Finn, Matthew D

2011-01-01

445

Topological optimisation of rod-stirring devices  

E-print Network

There are many industrial situations where rods are used to stir a fluid, or where rods repeatedly stretch a material such as bread dough or taffy. The goal in these applications is to stretch either material lines (in a fluid) or the material itself (for dough or taffy) as rapidly as possible. The growth rate of material lines is conveniently given by the topological entropy of the rod motion. We discuss the problem of optimising such rod devices from a topological viewpoint. We express rod motions in terms of generators of the braid group, and assign a cost based on the minimum number of generators needed to write the braid. We show that for one cost function -- the topological entropy per generator -- the optimal growth rate is the logarithm of the golden ratio. For a more realistic cost function,involving the topological entropy per operation where rods are allowed to move together, the optimal growth rate is the logarithm of the silver ratio, $1+\\sqrt{2}$. We show how to construct devices that realise this optimal growth, which we call silver mixers.

Matthew D. Finn; Jean-Luc Thiffeault

2010-04-05

446

Improvement of four anode rods ion source  

SciTech Connect

In this work, an improved form of a saddle field ion source has been designed and constructed. It consists of four anode rods made from copper and two copper cathode discs. The two cathode discs are placed symmetrically on both sides of the four anode rods. The electrical discharge and output ion beam characteristics were measured at different pressures using argon gas. The optimum distance between each two anode rods was determined. Also the optimum distance between the four anode rods and any cathode disc was obtained. It was found that the optimum distance between each two anode rods equal to 6 mm, while the optimum distance between the four anode rods and any cathode disc equal to 16 mm, where a stable discharge current and maximum output ion beam current can be obtained. The effect of negative extraction voltage applied to both the extractor electrode and Faraday cup on the output ion beam current was studied. The sputter yield of copper and aluminum targets using argon ions of different energies was determined.

Abdel Salam, F. W.; El-Khabeary, H.; Abdel Reheem, A. M. [Accelerators and Ion Sources Department, Nuclear Research Center, Atomic Energy Authority, P. No. 13759 (Egypt); Ahmed, M. M. [Physics Department, Faculty of Science, Helwan University, Cairo (Egypt)

2011-03-15

447

Open Spinning Strings  

E-print Network

We find classical open string solutions in the $AdS_5\\times S^5/\\Zop_2$ orientifold with angular momenta along the five-sphere. The energy of these solutions has an expansion in integral powers of $\\lambda$ with sigma-model corrections suppressed by inverse powers of $J$ - the total angular momentum. This gives a prediction for the exact anomalous dimensions of operators in the large $N$ limit of an ${\\cal N}=2$ $Sp(N)$ Super-Yang-Mills theory with matter. We also find a simple map between open and closed string solutions. This gives a prediction for an all-loop planar relationship between the anomalous dimensions of single-trace and two-quark operators in the dual gauge theory.

B. Stefanski Jr

2003-12-09

448

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

449

New expressions for string loop amplitudes leading to an ultrasimple conception of string dynamics  

Microsoft Academic Search

New expressions are derived for string loop amplitudes as overlap integrals of string wave functionals. They are shown to take the form of exchange terms coming from the Bose-Einstein symmetrization between string segments. One is thus led to the ultrasimple conception that string theory is basically free, and that ``string interactions'' are merely due to the fact that strings are

Chan Hong-Mo; Tsou Sheung Tsun; J. Bordes; Lukas Nellen

1991-01-01

450

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

DOE PAGESBeta

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

451

PP-wave String Interactions from String Bit Model  

E-print Network

We construct the string states $|O_{p}^J>_J$, $|O_{q}^{J_1}>_{{J_1}{J_2}}$ and $|O_{0}^{J_{1}J_{2}}>_{{J_1}{J_2}}$ in the Hilbert space of the quantum mechanical orbifold model so as to calculate the three point functions and the matrix elements of the light-cone Hamiltonian from the interacting string bit model. With these string states we show that the three point functions and the matrix elements of the Hamiltonian derived from the interacting string bit model up to $g^{2}_2$ order precisely match with those computed from the perturbative SYM theory in BMN limit.

Jian-Ge Zhou

2002-11-27

452

M-Theory and String-String Duality  

E-print Network

In this article we examine the compatibility of some recent results, results relating M-Theory to String Theory, with the string-string duality conjecture in six-dimensions. In particular, we rederive the relation between M-Theory and Type IIA strings. We then go on to examine in detail M-Theory on $K3 \\times S^{1}$ and its relation to the Heterotic theory on $T^{4}$. We conclude with some remarks on M-Theory on $T^{4}\\times (S^{1}/{\\bf Z}_{2})$ and its relation to the Type II theory on $K3$.

K. Davis

1996-01-19

453

String Quartet Theory  

Microsoft Academic Search

\\u000a Why are we including this topic in a book on performance theory? Couldn’t one include any other topic relating to a specific\\u000a musical genre as well? Solo piano music, operas, what not? The reason for the special role of the string quartet is that this\\u000a genre has a theory, a re ection about why these four instruments—the two violins, the

Guerino Mazzola

454

String theory and quintessence  

Microsoft Academic Search

We discuss the obstacles for defining a set of observable quantities analogous to an S-matrix which are needed to formulate string theory in an accelerating universe. We show that the quintessence models with the equations of state -1 < w < -1\\/3 have future horizons and may be no better suited to an S-matrix or S-vector description. We also show

Simeon Hellerman; Nemanja Kaloper; Leonard Susskind

2001-01-01

455

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

456

Swinging on a String  

NSDL National Science Digital Library

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

Integrated Teaching and Learning Program,

457

Brane waves and strings  

Microsoft Academic Search

Recently, solutions of the Born-Infeld theory representing strings emanating from a Dirichlet p-brane have been constructed. We discuss the embedding of these Bom-Infeld solutions into the non-abelian theory appropriate to multiple overlapping p-branes. We also prove supersymmetry of the solutions explicitly in the full non-linear theory. We then study transverse fluctuations, both from the world-brane point of view and by

Sangmin Lee; Amanda Peet; Lárus Thorlacius

1998-01-01

458

Statistics of String vacua  

Microsoft Academic Search

We give an introduction to the statistical approach to studying vacua of\\u000astring\\/M theory, and discuss recent results of Ashok and Douglas on counting\\u000asupersymmetric flux vacua in type IIb Calabi-Yau compactification.\\u000a To appear in the proceedings of the 2003 String Phenomenology workshop in\\u000aDurham, UK.

Michael R. Douglas

2004-01-01

459

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

2008-05-07

460

LHC String Phenomenology  

E-print Network

We argue that it is possible to address the deeper LHC Inverse Problem, to gain insight into the underlying theory from LHC signatures of new physics. We propose a technique which may allow us to distinguish among, and favor or disfavor, various classes of underlying theoretical constructions using (assumed) new physics signals at the LHC. We think that this can be done with limited data $(5-10 fb^{-1})$, and improved with more data. This is because of two reasons -- a) it is possible in many cases to reliably go from (semi)realistic microscopic string construction to the space of experimental observables, say, LHC signatures. b) The patterns of signatures at the LHC are sensitive to the structure of the underlying theoretical constructions. We illustrate our approach by analyzing two promising classes of string compactifications along with six other string-motivated constructions. Even though these constructions are not complete, they illustrate the point we want to emphasize. We think that using this technique effectively over time can eventually help us to meaningfully connect experimental data to microscopic theory.

Gordon L. Kane; Piyush Kumar; Jing Shao

2007-06-05

461

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

462

Black Holes in String Theory  

Microsoft Academic Search

The black hole solutions to Einstein's vacuum field equations are also\\u000asolutions to the equations of motion of the low energy limit of superstring\\u000atheory. At the same time, string theory boasts a much broader and richer\\u000acollection of black hole solutions. Fortunately, string theories also possess a\\u000aremarkable set of duality symmetries relating states within and between\\u000adifferent string

J. C. Breckenridge

1997-01-01

463

String Percolation and the Glasma  

E-print Network

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.

J. Dias de Deus; C. Pajares

2010-11-04

464

Cosmic Strings Lens Phenomenology Revisited  

Microsoft Academic Search

We present investigations of lens phenomenological properties of cosmic\\u000astrings for deep galaxy surveys. General results that have obtained for lineic\\u000aenergy distribution are presented first. We stress that generically the local\\u000aconvergence always vanishes in presence of strings although there might be some\\u000asignificant distortions. We then propose a simplified model of strings, we call\\u000a``Poisson strings'', for which

Francis Bernardeau; Jean-Philippe Uzan

2000-01-01

465

The second string (phenomenology) revolution  

Microsoft Academic Search

In the past three years our views on how the standard model of particle\\u000aphysics could be embedded into string theory have dramatically changed. The\\u000aheterotic string is no longer the only possibility for such an embedding and\\u000aother perturbative (or non-perturbative) corners of M-theory, like Type I or\\u000aType II strings seem now possible. It has also been realized

Luis E. Ibanez; Teorica C-XI

1999-01-01

466

Strings in de Sitter space  

E-print Network

We study both global as well as local (Nielsen-Olesen) strings in de Sitter space. While these type of topological defects have been studied in the background of a de Sitter metric previously, we study here the full set of coupled equations. We find only ``closed'' solutions. The behaviour of the metric tensor of these solutions resembles that of ``supermassive'' strings with a curvature singularity at the cosmological horizon. For global strings (and the composite defect) we are able to construct solutions which are regular on the interval from the origin to the cosmological horizon if the global string core lies completely inside the horizon.

Eugenio R. Bezerra de Mello; Yves Brihaye; Betti Hartmann

2003-04-04

467

Evolution of cosmic string networks  

NASA Technical Reports Server (NTRS)

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

Albrecht, Andreas; Turok, Neil

1989-01-01

468

Black Holes in String Theory  

E-print Network

The black hole solutions to Einstein's vacuum field equations are also solutions to the equations of motion of the low energy limit of superstring theory. At the same time, string theory boasts a much broader and richer collection of black hole solutions. Fortunately, string theories also possess a remarkable set of duality symmetries relating states within and between different string theories. These duality symmetries can be exploited to construct new black hole solutions from known solutions, giving us powerful tools with which to explore the black hole solutions of string theory. Here we introduce and demonstrate these techniques of solution generating.

J. C. Breckenridge

1997-08-27

469

Magnetosphere of a spinning string  

E-print Network

In this note we observe that the exact Maxwell-Einstein equations in the background metric of a spinning string can be solved analytically. This allows us to construct an analytical model for the magnetosphere which is approximately force free near to the spinning string. As in the case of a Kerr black hole in the presence of an external magnetic field the spinning string will acquire an electric charge which depends on the vorticity carried by the spinning string. The self-generated magnetic field and currents strongly resemble the current and magnetic field structure of the jets associated with active galaxies as they emerge from the galactic center.

George Chapline; James Barbieri

2012-01-02

470

The effective theory of strings  

E-print Network

We show that the Nambu-Goto string, and its higher dimensional generalizations, can be quantized, in the sense of an effective theory, in any dimension of the target space. The crucial point is to consider expansions around classical string configurations. We are using tools from perturbative algebraic quantum field theory, quantum field theory on curved spacetimes, and the Batalin-Vilkovisky formalism. Our model has some similarities with the L\\"uscher-Weisz string, but we allow for arbitrary classical background string configurations and keep the diffeomorphism invariance.

Dorothea Bahns; Katarzyna Rejzner; Jochen Zahn

2013-11-26

471

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

SciTech Connect

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.

Munkittrick, K.R.; Dixon, D.G.

1988-02-01

472

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

473

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

474

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

475

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

476

Dissipative particle dynamics simulations on self-assembly of rod-coil-rod triblock copolymers in a rod-selective solvent  

NASA Astrophysics Data System (ADS)

Self-assembly of rod-coil-rod ABA triblock copolymers in a rod-selective solvent is investigated by using dissipative particle dynamics simulations. The morphologies of the self-assembled aggregates are dependent on the number of copolymers in the aggregate and the rod length of the copolymer. We observe vesicles at short rod block and bowl-like aggregates at slightly longer rod block. In the vesicle region near the phase boundary, metastable bowl-like aggregates can be observed and be transformed into vesicles by annealing process. A transition from the bowl-like structure to the vesicle is observed by increasing the solvophobicity of the mid-coil block. In this study, the difference between the self-assembly of fully flexible ABA triblock copolymer and that of rod-coil-rod triblock copolymer is also discussed.

Huang, Jian-Hua; Fan, Zhong-Xiang; Ma, Ze-Xin

2013-08-01

477

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

Microsoft Academic Search

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

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

2006-01-01

478

Transmission of scotopic signals from the rod to rod-bipolar cell in the mammalian retina  

E-print Network

in only one out of thousands of rod photoreceptors. At such low light levels, vision is mediated Abstract Mammals can see at low scotopic light levels where only 1 rod in several thousand transduces excellent night vision, and can perform well at scotopic light levels that pro- duce photoisomerizations

Pennsylvania, University of

479

Gyrating strings: A new instability of black strings?  

SciTech Connect

A thermodynamic argument is presented suggesting that near-extremal spinning D1-D5-P black strings become unstable when their angular momentum exceeds J{sub crit}=3Q{sub 1}Q{sub 5}/2{radical}(2). In contrast, the dimensionally reduced black holes are thermodynamically stable. The proposed instability involves a phase in which the spin angular momentum above J{sub crit} is transferred to gyration of the string in space, i.e., to orbital angular momentum of parts of the string about the mean location in space. Thus the string becomes a rotating helical coil. We note that an instability of this form would yield a counter-example to the Gubser-Mitra conjecture, which proposes a particular link between dynamic black string instabilities and the thermodynamics of black strings. There may also be other instabilities associated with radiation modes of various fields. Our arguments also apply to the D-brane bound states associated with these black strings in weakly coupled string theory.

Marolf, Donald; Palmer, Belkis Cabrera [Physics Department, University of California at Santa Barbara, Santa Barbara, California 93106 (United States); Physics Department, Syracuse University, Syracuse, New York 13244 (United States); Physics Department, University of California at Santa Barbara, Santa Barbara, California 93106 (United States)

2004-10-15

480

Type IIA String and Matrix String on PP-wave  

E-print Network

We study type IIA string theories on the pp-waves with 24 supercharges. The type IIA pp-wave backgrounds are derived from the maximally supersymmetric pp-wave solution in eleven dimensions through the toroidal compactification on the spatial isometry directions. The associated actions of type IIA strings are obtained by using these metrics and other background fields of the type IIA supergravities on the one hand. On the other hand, we derive these theories from D=11 supermembrane on the pp-wave via double dimensional reduction for the spatial isometry directions. The resulting actions agree with those of type IIA strings obtained in the study of the supergravities. Also, the action of the matrix string is written down. Moreover, the quantization of closed and open strings is discussed. In particular, we study Dp-branes allowed in one of the type IIA theories.

Katsuyuki Sugiyama; Kentaroh Yoshida

2002-09-10

481

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

482

Passive electrical properties of rod outer segments  

PubMed Central

1. Measurements on a packed suspension of randomly oriented, dark-adapted frog rods at frequencies of 15 c/s-0·5 Mc/s indicate a behaviour similar to that of other biological materials. 2. Results are analysed on the assumption that the low-frequency limiting resistance is determined by current flowing in the suspending medium and that, of the rods, two thirds are oriented perpendicular to the applied field and one third parallel to it. Those parallel to the field are treated as non-conductors. 3. From the high-frequency limiting resistance the conductivity of the rod interior is calculated to vary linearly with the conductivity of the medium. The slope of the relation of internal to external conductivity is 0·50 with a limiting internal conductivity (at zero external) of 280 ?mho/cm. 4. On the assumption that the suspension can be represented as a single-capacitance network, the characteristic frequency of impedance is used to calculate a capacitance for the rod surface of 1·54 ?F/cm2. On the assumption of a distribution in properties of the suspension according to the theory of Bruggeman, the capacitance is calculated to have a value of about one half this. 5. At frequencies below 5 kc/s the impedance locus deviates from the curve describing the behaviour at higher frequencies. It is suggested that this may involve conduction in a thin layer extending along the surface of the rod. PMID:5685292

Falk, Gertrude; Fatt, P.

1968-01-01

483

Coiling of elastic rods on rigid substrates  

PubMed Central

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 toward developing predictive understanding of the coiling process. Both cases of deposition onto static and moving substrates are considered. We construct phase diagrams for the possible coiling patterns and characterize them as a function of the geometric and material properties of the rod, as well as the height and relative speeds of deployment. The modes selected and their characteristic length scales are found to arise from a complex interplay between gravitational, bending, and twisting energies of the rod, coupled to the geometric nonlinearities intrinsic to the large deformations. We give particular emphasis to the first sinusoidal mode of instability, which we find to be consistent with a Hopf bifurcation, and analyze the meandering wavelength and amplitude. Throughout, we systematically vary natural curvature of the rod as a control parameter, which has a qualitative and quantitative effect on the pattern formation, above a critical value that we determine. The universality conferred by the prominent role of geometry in the deformation modes of the rod suggests using the gained understanding as design guidelines, in the original applications that motivated the study. PMID:25267649

Jawed, Mohammad K.; Da, Fang; Joo, Jungseock; Grinspun, Eitan; Reis, Pedro M.

2014-01-01

484

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

485

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

2004-05-06

486

Application of multi-stable isotope (?13C, ?15N, ?34S, ?37Cl) assays to assess spatial separation of fish (longnose sucker Catostomus catostomus) in an area receiving complex effluents  

Microsoft Academic Search

Incorporation of stable isotope analysis (SIA) into routine environmental effects monitoring programs of receiving waters may enable determination of the spatial extent of biotic exposure and discrimination among sources of complex effluents. To evaluate this hypothesis, longnose sucker (Catostomus catostomus) were collected from four sites along the Athabasca River, Alberta (upstream reference site, two sites downstream of effluents from two

M. G. Dube; Glenn A. Benoy; Sandra Blenkinsopp; Jenny-Marie Ferone; Robert B. Brua; Leonard I. Wassenaar

2005-01-01

487

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

2011-05-24

488

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

489

The covariant perturbative string spectrum  

E-print Network

We provide generating functions for the perturbative massive string spectrum which are covariant with respect to the SO(9) little group, and which contain all the representation theoretic content of the spectrum. Generating functions for perturbative bosonic, Type II, Heterotic and Type I string theories are presented, and generalizations are discussed.

Davide Forcella; Amihay Hanany; Jan Troost

2011-03-08

490

Cosmic Strings and Black Holes  

E-print Network

In the first part of this talk, I consider some exact string solutions in curved spacetimes. In curved spacetimes with a Killing vector (timelike or spacelike), the string equations of motion and constraints are reduced to the Hamilton equations of a relativistic point-particle in a scalar potential, by imposing a particular ansatz. As special examples I consider circular strings in axially symmetric spacetimes, as well as stationary strings in stationary spacetimes. In the second part of the talk, I then consider in more detail the stationary strings in the Kerr -Newman geometry. It is shown that the world-sheet of a stationary string, that passes the static limit of the 4-D Kerr-Newman black hole, describes a 2-D black hole. Mathematical results for 2-D black holes can therefore be applied to physical objects; (say) cosmic strings in the vicinity of Kerr black holes. As an immediate general result, it follows that the string modes are thermally excited.

A. L. Larsen

1996-10-09

491

Electromagnetic self interaction in strings  

E-print Network

To facilitate the treatment of electromagnetic effects in applications such as dynamically perturbed vortons, this work employs a covariantly formulated string-source Green measure to obtain a coherent relativistic scheme for describing the self interaction of electromagnetic currents in string models of a very general kind, at leading order in the relevant field gradients, using a regularised gradient operator given by $\\hat\

Brandon Carter

1997-04-30

492

Open string fields as matrices  

NASA Astrophysics Data System (ADS)

We show that the action expanded around Erler-Maccaferri's N D-brane solution describes the N+1 D-brane system where one D-brane disappears due to tachyon condensation. String fields on multi-branes can be regarded as block matrices of a string field on a single D-brane in the same way as matrix theories.

Kishimoto, Isao; Masuda, Toru; Takahashi, Tomohiko; Takemoto, Shoko

2015-03-01

493

Fermions on the Electroweak String  

E-print Network

We construct a simple class of exact solutions of the electroweak theory including the naked $Z$--string and fermion fields. It consists in the $Z$--string configuration ($\\phi,Z_\\theta$), the {\\it time} and $z$ components of the neutral gauge bosons ($Z_{0,3},A_{0,3}$) and a fermion condensate (lepton or quark) zero mode. The $Z$--string is not altered (no feed back from the rest of fields on the $Z$--string) while fermion condensates are zero modes of the Dirac equation in the presence of the $Z$--string background (no feed back from the {\\it time} and $z$ components of the neutral gauge bosons on the fermion fields). For the case of the $n$--vortex $Z$--string the number of zero modes found for charged leptons and quarks is (according to previous results by Jackiw and Rossi) equal to $|n|$, while for (massless) neutrinos is $|n|-1$. The presence of fermion fields in its core make the obtained configuration a superconducting string, but their presence (as well as that of $Z_{0,3},A_{0,3}$) does not enhance the stability of the $Z$--string.

J. M. Moreno; D. H. Oaknin; M. Quirós

1994-11-28

494

Size and shape of strings  

SciTech Connect

The authors study numerically and analytically spatial properties of the ground state of a fundamental string in the light-cone gauge. They find that strings are smooth and have divergent average size. Their properties are very different from what is expected from particles in a conventional field theory.

Karliner, M.; Klebanov, I. (Stanford Univ., CA (USA)); Susskind, L. (Stanford Univ., CA (USA). Dept. of Physics)

1988-01-01

495

Improving cosmic string network simulations  

E-print Network

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

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

2014-09-02

496

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

497

undergraduate jazz & improvisationmusic theory strings  

E-print Network

undergraduate programs jazz & improvisationmusic theory strings music educationtheatre & drama Education 40 Music Theory 42 Musical Theatre 50 Musicology 54 Organ 57 Performing Arts Technology 62 Piano 66 Strings 72 Theatre & Drama 82 Voice 88 Winds & Percussion 96 Contact Information 5 #12;Degree

Shyy, Wei

498

Dark Energy in String Theory  

NASA Astrophysics Data System (ADS)

We review the tension between the observational evidence for dark energy and various theoretical considerations. This tension has motivated a reconsideration of the issue of naturalness, and spawned various exotic approaches toward an acceptable solution. We discuss attempts to realize dark energy in string theory, and the perspective on the string landscape that these results have suggested.

Greene, Brian; Shiu, Gary

2014-12-01

499

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

500

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