An introduction to the Kähler-Ricci flow

CERN Document Server

Eyssidieux, Philippe; Guedj, Vincent

2013-01-01

This volume collects lecture notes from courses offered at several conferences and workshops, and provides the first exposition in book form of the basic theory of the Kähler-Ricci flow and its current state-of-the-art. While several excellent books on Kähler-Einstein geometry are available, there have been no such works on the Kähler-Ricci flow. The book will serve as a valuable resource for graduate students and researchers in complex differential geometry, complex algebraic geometry and Riemannian geometry, and will hopefully foster further developments in this fascinating area of research.   The Ricci flow was first introduced by R. Hamilton in the early 1980s, and is central in G. Perelman’s celebrated proof of the Poincaré conjecture. When specialized for Kähler manifolds, it becomes the Kähler-Ricci flow, and reduces to a scalar PDE (parabolic complex Monge-Ampère equation). As a spin-off of his breakthrough, G. Perelman proved the convergence of the Kähler-Ricci flow on Kähler-Einstein man...

The classification of the Ricci tensor in the general theory of relativity

International Nuclear Information System (INIS)

Cormack, W.J.

1979-10-01

A comprehensive classification of the Ricci tensor in General Relativity using several techniques is given and their connection with existing classification studied under the headings; canonical forms for the Ricci tensor, invariant 2-spaces in the classification of the Ricci tensor, Riemannian curvature and the classification of the Riemann and Ricci tensors, and spinor classifications of the Ricci tensor. (U.K.)

Ricci inheritance symmetry in general relativity

International Nuclear Information System (INIS)

Bokhari, A.H.; Al-Dweik, A.; Zaman, F.D.; Karim, M.; Kubel, D.

2010-01-01

In an earlier paper (see Nuovo Cimento B, 19 (2004) 1187) it was conjectured that none of the well-known spherically symmetric static space-time solutions of the Einstein equations admit non-trivial Ricci inheritance symmetry. In this paper we discuss Ricci inheritance (R I) symmetry in three well-known non static spherically symmetric space-time metrics and show that our conjecture is also valid in non-static space-time metrics.

Spacetimes of Weyl and Ricci type N in higher dimensions

International Nuclear Information System (INIS)

Kuchynka, M; Pravdová, A

2016-01-01

We study the geometrical properties of null congruences generated by an aligned null direction of the Weyl tensor (WAND) in spacetimes of Weyl and Ricci type N (possibly with a non-vanishing cosmological constant) in an arbitrary dimension. We prove that a type N Ricci tensor and a type III or N Weyl tensor have to be aligned. In such spacetimes, the multiple WAND has to be geodetic. For spacetimes with type N aligned Weyl and Ricci tensors, the canonical form of the optical matrix in the twisting and non-twisting cases is derived and the dependence of the Weyl and the Ricci tensors and Ricci rotation coefficients on the affine parameter of the geodetic null congruence generated by the WAND is obtained. (paper)

50 CFR 21.46 - Depredation order for depredating scrub jays and Steller's jays in Washington and Oregon.

Science.gov (United States)

2010-10-01

..., without a permit, take scrub jays (Aphelocoma coerulescens) and Steller's jays (Cyanocitta stelleri) when... transported or sold or offered for sale except that, such transportation within the area, as may be necessary... the State agricultural department, college, or other public institution may requisition such scrub...

Managing nuclear safety at Point Lepreau

Energy Technology Data Exchange (ETDEWEB)

Paciga, J [New Brunswick Power, Point Lepreau NGS, PQ (Canada)

1997-12-01

Managing nuclear safety at Point Lepreau nuclear power plant is described, including technical issues (station aging, definition of the safe operating envelope, design configuration management, code validation, safety analysis and engineering standards); regulatory issues (action items, probabilistic safety assessment, event investigation, periodic safety review, prioritization of regulatory issues, cost benefit assessment); human performance issues (goals and measures, expectations and accountability, supervisory training, safety culture, configuration management, quality of operations and maintenance).

Managing nuclear safety at Point Lepreau

International Nuclear Information System (INIS)

Paciga, J.

1997-01-01

Managing nuclear safety at Point Lepreau nuclear power plant is described, including technical issues (station aging, definition of the safe operating envelope, design configuration management, code validation, safety analysis and engineering standards); regulatory issues (action items, probabilistic safety assessment, event investigation, periodic safety review, prioritization of regulatory issues, cost benefit assessment); human performance issues (goals and measures, expectations and accountability, supervisory training, safety culture, configuration management, quality of operations and maintenance)

Point Lepreau nuclear project unlocks power future of New Brunswick

Energy Technology Data Exchange (ETDEWEB)

Burgess, E J [New Brunswick Electric Power Commission, Fredericton (Canada)

1976-08-01

Projects under development will increase the generating capacity of New Brunswick Electric Power Commission from 1.47 to 3.14 GW. Of these projects, the most significant is the 0.63 GW Point Lepreau CANDU reactor. Progress in the construction of the power reactor is summarized. The concrete reactor building was slipformed in April 1976. A second nuclear unit at Point Lepreau is being considered. Information is also provided on the new oil-fired station at Coleson Cove, a new oil- or coal-fired unit at Dalhousie and further hydro units at Mactaquac. A 0.16 GW pumped storage hydro unit at Green River is being considered. Information on transmission (Including the HVDC system), substations, and connection with Hydro Quebec is included.

Point Lepreau refurbishment: plant condition assessment

International Nuclear Information System (INIS)

Allen, P.J.; Soulard, M.R.; David, F.; Clefton, G.; Weeks, R.

2001-01-01

New Brunswick Power (NB Power) has initiated a study into the refurbishment of the Point Lepreau Generating Station, with the objective to extend plant operation another 25 to 30 years. The end product of this study will be a business case that compares the costs of refurbishing Point Lepreau with costs of alternate means of generation. The Project Execution Plan and business case are being developed by an integrated team of AECL, NB Power and subcontractor staff under the project management of AECL. The refurbishment scope will include replacement of the pressure tubes, calandria tubes and part of the feeder piping. Planning of these replacements is part of the refurbishment study work. Planning is also underway for the environmental, safety and licensing issues that would need to be addressed to ensure future operation of the unit. In addition to these studies, a systematic review of the plant has been carried out to determine what other equipment refurbishment or replacement will be required due to ageing or obsolescence of plant equipment. This Plant Condition Assessment (PCA) follows a highly structured approach to ensure consistency. This paper presents an overview of the engineering process and the main findings from the work. (author)

Emergency response guide for Point Lepreau area residents

International Nuclear Information System (INIS)

1982-01-01

The design, construction and operating procedures of CANDU nuclear generating stations ensure that an accident causing a significant risk to people living near these stations is extremely unlikely. However, despite the excellent safety record of nuclear stations, it is common practice to prepare an emergency plan for such facilities. In this regard, The New Brunswick Emergency Measures Organization is responsible for developing and implementing the Off-Site Emergency Plan for the Point Lepreau Generating Station. Work for the Off-Site Emergency Plan began in 1976 and, under the leadership of N.B.E.M.O., a number of government agencies co-operated in this project. The completed plan thus represents agreement among a number of Province of New Brunswick departments, various community groups, NB Power, and representatives of the Government of Canada. Also, information gathered in the annual door-to-door survey of the Lepreau area enabled government planners to make specialized arrangements such as an extensive warden service, a siren system, and evacuation assistance for the disabled

Piagetian object permanence and its development in Eurasian jays (Garrulus glandarius).

Science.gov (United States)

Zucca, Paolo; Milos, Nadia; Vallortigara, Giorgio

2007-04-01

Object permanence in Eurasian jays (Garrulus glandarius) was investigated using a complete version of the Uzgiris and Hunt scale 1. Nine hand-raised jays were studied, divided into two groups according to their different developmental stages (experiment 1, older jays: 2-3 months old, n = 4; experiment 2, younger jays: 15 days old, n = 5). In the first experiment, we investigated whether older jays could achieve piagetian stage 6 of object permanence. Tasks were administered in a fixed sequence (1-15) according to the protocols used in other avian species. The aim of the second experiment was to check whether testing very young jays before their development of "neophobia" could influence the achievement times of piagetian stages. Furthermore, in this experiment tasks were administered randomly to investigate whether the jays' achievement of stage 6 follows a fixed sequence related to the development of specific cognitive abilities. All jays tested in experiments 1 and 2 fully achieved piagetian stage 6 and no "A not B" errors were observed. Performance on visible displacement tasks was better than performance on invisible ones. The results of experiment 2 show that "neophobia" affected the response of jays in terms of achievement times; the older jays in experiment 1 took longer to pass all the tasks when compared with the younger, less neophobic, jays in experiment 2. With regard to the achieving order, jays followed a fixed sequence of acquisition in experiment 2, even if tasks were administered randomly, with the exception of one subject. The results of these experiments support the idea that piagetian stages of cognitive development exist in avian species and that they progress through relatively fixed sequences.

Non-adiabatic perturbations in Ricci dark energy model

International Nuclear Information System (INIS)

Karwan, Khamphee; Thitapura, Thiti

2012-01-01

We show that the non-adiabatic perturbations between Ricci dark energy and matter can grow both on superhorizon and subhorizon scales, and these non-adiabatic perturbations on subhorizon scales can lead to instability in this dark energy model. The rapidly growing non-adiabatic modes on subhorizon scales always occur when the equation of state parameter of dark energy starts to drop towards -1 near the end of matter era, except that the parameter α of Ricci dark energy equals to 1/2. In the case where α = 1/2, the rapidly growing non-adiabatic modes disappear when the perturbations in dark energy and matter are adiabatic initially. However, an adiabaticity between dark energy and matter perturbations at early time implies a non-adiabaticity between matter and radiation, this can influence the ordinary Sachs-Wolfe (OSW) effect. Since the amount of Ricci dark energy is not small during matter domination, the integrated Sachs-Wolfe (ISW) effect is greatly modified by density perturbations of dark energy, leading to a wrong shape of CMB power spectrum. The instability in Ricci dark energy is difficult to be alleviated if the effects of coupling between baryon and photon on dark energy perturbations are included

CIME course on Ricci Flow and Geometric Applications

CERN Document Server

Mantegazza, Carlo

2016-01-01

Presenting some impressive recent achievements in differential geometry and topology, this volume focuses on results obtained using techniques based on Ricci flow. These ideas are at the core of the study of differentiable manifolds. Several very important open problems and conjectures come from this area and the techniques described herein are used to face and solve some of them. The book's four chapters are based on lectures given by leading researchers in the field of geometric analysis and low-dimensional geometry/topology, respectively offering an introduction to: the differentiable sphere theorem (G. Besson), the geometrization of 3-manifolds (M. Boileau), the singularities of 3-dimensional Ricci flows (C. Sinestrari), and Kahler-Ricci flow (G. Tian). The lectures will be particularly valuable to young researchers interested in differential manifolds.

Blue jay attacks and consumes cedar waxwing

Science.gov (United States)

Daniel Saenz; Joshua B. Pierce

2009-01-01

Blue Jays (Cyanocitta cristata) are known to be common predators on bird nests (Wilcove 1985, Picman and Schriml 1994). In addition to predation on eggs and nestlings, Blue Jays occasionally prey on fledgling and adult birds (Johnson and Johnson 1976, Dubowy 1985). A majority of reports involve predation on House Sparrows (Passer domesticus) and other small birds (...

Statefinder diagnosis for Ricci dark energy

International Nuclear Information System (INIS)

Feng Chaojun

2008-01-01

Statefinder diagnostic is a useful method which can differ one dark energy model from each others. In this Letter, we apply this method to a holographic dark energy model from Ricci scalar curvature, called the Ricci dark energy model (RDE). We plot the evolutionary trajectories of this model in the statefinder parameter-planes, and it is found that the parameter of this model plays a significant role from the statefinder viewpoint. In a very special case, the statefinder diagnostic fails to discriminate LCDM and RDE models, thus we apply a new diagnostic called the Om diagnostic proposed recently to this model in this case in Appendix A and it works well

Tunnel system for ocean cooling water for Point Lepreau

International Nuclear Information System (INIS)

Pullerits, K.

1980-01-01

The New Brunswick Electric Power Commission is building a 600 MW nuclear generating station at Point Lepreau. Of major consideration in the design of a nuclear power plant is the enormous heat loss from the plant's operation, and the effective disposal of this heat energy through condensers and turbines into the environment. Heat diffusion was a factor in the selection of the Point Lepreau site. High tides with peak velocities of up to three knots cause effective mixing of the ocean waters and provide a heat sink large enough for two 600 MW units. It was decided to locate an intake tunnel off the east side of the peninsula and an outlet tunnel off the west side, surface structures having been ruled out because of possible wave damage. In addition to water flow rate and velocity, the protection of fish and shellfish, wave impact, and navigational clearance requirements had to be considered in the design of the intake structure. A surge tank was included in the outfall system. Construction of the tunnels is described. (LL)

AECB staff annual assessment of the Point Lepreau Nuclear Generating Station for the year 1995

International Nuclear Information System (INIS)

1996-06-01

The Atomic Energy Control Board conducts a staff assessment of safety at Point Lepreau Generating Station for 1995. On-site Project Officers and Ottawa based specialists monitored the station throughout the year. Point Lepreau operated safely during 1995 which was an unusual year for the station. The station was shut down for a planned five month outage to allow NB Power to complete maintenance on the reactor's pressure tubes. NB Power failed to comply with the terms of the Operating Licence we issue on fourteen occasions in 1995. In addition, NB Power reported an unusually large number of events. None of the events themselves directly affected public safety, if this level of performance continues unchecked, it might result in increased risk from operation in the future. Human error was an important feature of these problems. NB Power had already introduced safety culture training for their staff, but they will need to undertake further work urgently to resolve the problems. Three of Point Lepreau's special safety systems failed to meet their availability targets during 1995. NB Power's safety analysis program progress slowed during 1995, due to the additional workload from the outage. The Point Lepreau's training, quality assurance and safeguards related activities continued to function satisfactorily. They have assigned additional resources to emergency preparedness planning, which should enable them to take a more pro-active approach in this area. 7 tabs., 5 figs

AECB staff annual assessment of the Point Lepreau Nuclear Generating Station

International Nuclear Information System (INIS)

1997-06-01

The Atomic Energy Control Board is the independent federal agency that controls all nuclear activities in Canada. A major use of nuclear energy in Canada is electricity production. The AECB assesses every station's performance against legal requirements, including the conditions in the operating licence. Each station is inspected and all aspects of the station's operation and management is reviewed. This report is the AECB staff assessment of reactor safety at the Point Lepreau Generating Station in 1996. Point Lepreau operated safely but the worsening trends in NB Power's safety performance leads to the conclusion that urgent action is required. NB Power is required to report formally to the AECB on progress with measures to improve safety management every six months. Further licensing action will be taken on NB Power if it fails to make the improvements

RICCI and matter collineations of som-roy chaudhary symmetric space time

International Nuclear Information System (INIS)

Ramzan, M.; Ahmed, Y.; Mufti, M.

2018-01-01

This paper is devoted to explore the RICCI and MCs (Matter Collineations of the Som-Ray Chaudhary spacetime. The spacetime under consideration is one of the spatially homogeneous and rotating spacetimes. Collineations are the some kinds of the Lie symmetries. To discuss the required collineations we have used the RICCI and energy momentum tensors. As the RICCI tensor is formulated from the metric tensor, it must possess its symmetries. RCs (RICCI Collineations) leads to conservation laws. On the other hand for the distribution of matter in the spacetimes, the symmetries of energy momentum tensor or MCs provides conservation laws on matter field. Throughout this paper, these collineations are discussed by vanishing Lie derivative of RICCI and energy momentum tensors respectively. Complete solution of the RCs and MCs equations, which are formed in the result of vanishing Lie derivative are explored. Studying all these collineations in the said spacetime, it has been shown that RCs of the spacetime form an infinite dimensional vector space where as MCs are Killing vector fields. (author)

Performance assessment of Point Lepreau Generating Station

International Nuclear Information System (INIS)

Alikhan, S.

1991-01-01

The Point Lepreau Generating Station, a 680 MWe CANDU unit, is located about 40 km southwest of the city of Saint John, New Brunswick, Canada. It was declared in-service on 1 February, 1983 and, since then, has demonstrated an average cross capacity factor of over 93% up to the end of 1990. This paper compared the performance of the station with other sister CANDU units and the Light Water Reactors world-wide using the following ten performance indicators, as applicable: - gross capacity factor; - fuel burn-up; - heavy water upkeep; - unplanned reactor trips while critical; - forced outage rate; - fuel handling performance; - derived emission of radioactive effluents to environment; - personnel radiation dose; - industrial safety; - low-level solid radioactive wastes. The paper examines various areas of station activities including management and organization, operations and maintenance, technical support, fuel handling and health physics in order to highlight some of the 'good practices' which are believed to have made a significant contribution towards achieving the demonstrated performance of Point Lepreau G.S. In addition, several areas of potential improvement are discussed in order to maintain and enhance, where practicable, the safety, reliability and economic performance of the station. In this context, a careful review of the operating experiences, both in-house and at other stations, and a judicious application of lessons learned plays a significant role. (author)

Performance assessment of Point Lepreau Generating Station

Energy Technology Data Exchange (ETDEWEB)

Alikhan, S [Point Lepreau Generating Station, Lepreau, NB (Canada)

1991-04-01

The Point Lepreau Generating Station, a 680 MWe CANDU unit, is located about 40 km southwest of the city of Saint John, New Brunswick, Canada. It was declared in-service on 1 February, 1983 and, since then, has demonstrated an average cross capacity factor of over 93% up to the end of 1990. This paper compared the performance of the station with other sister CANDU units and the Light Water Reactors world-wide using the following ten performance indicators, as applicable: - gross capacity factor; - fuel burn-up; - heavy water upkeep; - unplanned reactor trips while critical; - forced outage rate; - fuel handling performance; - derived emission of radioactive effluents to environment; - personnel radiation dose; - industrial safety; - low-level solid radioactive wastes. The paper examines various areas of station activities including management and organization, operations and maintenance, technical support, fuel handling and health physics in order to highlight some of the 'good practices' which are believed to have made a significant contribution towards achieving the demonstrated performance of Point Lepreau G.S. In addition, several areas of potential improvement are discussed in order to maintain and enhance, where practicable, the safety, reliability and economic performance of the station. In this context, a careful review of the operating experiences, both in-house and at other stations, and a judicious application of lessons learned plays a significant role. (author)

Lepreau 2 environmental impact statement. Supplemental information

International Nuclear Information System (INIS)

1984-09-01

This report contains supplemental information to the Environmental Impact Statement that was issued on the proposed second nuclear generating station Point Lepreau-2 in New Brunswick, Canada. Some issues dealt with here are the terrestrial and aquatic impacts of radioactive and thermal releases to the environment, radiation safety for the human population, socio-economic impacts on the region in regards to housing, social services and employment, and monitoring programs for all aspects of the development, construction and operation of the plant

Ricci-flat branes

International Nuclear Information System (INIS)

Brecher, D.; Perry, M.J.

2000-01-01

Up to overall harmonic factors, the D8-brane solution of the massive type IIA supergravity theory is the product of nine-dimensional Minkowski space (the world-volume) with the real line (the transverse space). We show that the equations of motion allow for the world-volume metric to be generalised to an arbitrary Ricci-flat one. If this nine-dimensional Ricci-flat manifold admits Killing spinors, then the resulting solutions are supersymmetric and satisfy the usual Bogomol'nyi bound, although they preserve fewer than the usual one half of the supersymmetries. We describe the possible choices of such manifolds, elaborating on the connection between the existence of Killing spinors and the self-duality condition on the curvature two-form. Since the D8-brane is a domain wall in ten dimensions, we are led to consider the general case: domain walls in any supergravity theory. Similar considerations hold here also. Moreover, it is shown that the world-volume of any magnetic brane - of which the domain walls are a specific example - can be generalised in precisely the same way. The general class of supersymmetric solutions have gravitational instantons as their spatial sections. Some mention is made of the world-volume solitons of such branes

Refurbishment implications on long-term waste management strategies at Point Lepreau

International Nuclear Information System (INIS)

Hickman, C.

2011-01-01

This paper discusses Point Lepreau Generating Station's waste management experiences during the Refurbishment outage. In short, Point Lepreau GS has been challenged during the outage due to the amount of low and intermediate level waste that has been generated compared to that which was expected, which has driven the need to develop a new waste management strategy in the middle of the outage. The paper presents an overview of pre-outage waste handling, what process changes and schedule changes occurred during the outage, and provides a discussion of the operational and financial consequences of those changes. Key issues highlighted by the paper include the need for adequate provision of waste management facilities during large outages, the importance of ensuring that contractors have a stake in waste minimization activities, and long term waste management implications that need to be considered for large outages.

The Ricci flow part IV : long-time solutions and related topics

CERN Document Server

Chow, Bennett; Glickenstein, David; Isenberg, James

2015-01-01

Ricci flow is a powerful technique using a heat-type equation to deform Riemannian metrics on manifolds to better metrics in the search for geometric decompositions. With the fourth part of their volume on techniques and applications of the theory, the authors discuss long-time solutions of the Ricci flow and related topics. In dimension 3, Perelman completed Hamilton's program to prove Thurston's geometrization conjecture. In higher dimensions the Ricci flow has remarkable properties, which indicates its usefulness to understand relations between the geometry and topology of manifolds. This b

Mass-induced instability of SAdS black hole in Einstein-Ricci cubic gravity

Science.gov (United States)

Myung, Yun Soo

2018-05-01

We perform the stability analysis of Schwarzschild-AdS (SAdS) black hole in the Einstein-Ricci cubic gravity. It shows that the Ricci tensor perturbations exhibit unstable modes for small black holes. We call this the mass-induced instability of SAdS black hole because the instability of small black holes arises from the massiveness in the linearized Einstein-Ricci cubic gravity, but not a feature of higher-order derivative theory giving ghost states. Also, we point out that the correlated stability conjecture holds for the SAdS black hole by computing the Wald entropy of SAdS black hole in Einstein-Ricci cubic gravity.

Point Lepreau: One of the world's best

International Nuclear Information System (INIS)

Taylor, G.M.

1992-01-01

General management aspects of and technical information about the Point Lepreau generating station in Canada are presented; the plant has one of the best lifetime operating records of any nuclear power plant in the world, and the best of any Candu reactor. The Candu-6 design is briefly described, and performance statistics are tabulated for a 5-year period. Aspects of plant operation discussed in some detail include planning meetings, outage management, health physics, computer control systems, and fuel handling. The role of onsite representative of the Atomic Energy Control Board is also described

Environmental monitoring report for the Point Lepreau, New Brunswick nuclear generating station 1984

International Nuclear Information System (INIS)

Nelson, R.W.P.; Ellis, K.M.; Smith, J.N.

1986-07-01

The Point Lepreau Environmental Monitoring Program (PLEMP) has been established within the Department of Fisheries and Oceans to assess the environmental impact of radioactive, thermal, and chemical releases from the Point Lepreau, N.B. Nuclear Generating Station (NGS) located on the Bay of Fundy. This report contains the results for the second year of the operational phase of the monitoring program. Emphasis has been placed on those areas where effects from the NGS operation were expected to be observed. Further studies were carried out on the characterization of the thermal plume during several pre-arranged tritium releases. Attention was given to tritium levels at the outfall, in the atmosphere and in biological samples. An initial attempt was made to relate the distribution of tritium in the Point Lepreau area in various phases to local meteorological conditions. Radionuclide levels in lichen, including, for the first time, aerial lichen on a regular basis, an efficient accumulator of atmospheric particulates were monitored. In addition, radionuclide measurements were made on samples collected during the pre-operational phase from the major environmental reservoirs and these radioactivity levels were compared to previous measurements to assess the impact of the operation of the NGS. The purpose of this program is to provide government with a comprehensive scientific basis upon which to assess the environmental implications of the operation of nuclear reactors in coastal regions

The simplicial Ricci tensor

International Nuclear Information System (INIS)

Alsing, Paul M; McDonald, Jonathan R; Miller, Warner A

2011-01-01

The Ricci tensor (Ric) is fundamental to Einstein's geometric theory of gravitation. The three-dimensional Ric of a spacelike surface vanishes at the moment of time symmetry for vacuum spacetimes. The four-dimensional Ric is the Einstein tensor for such spacetimes. More recently, the Ric was used by Hamilton to define a nonlinear, diffusive Ricci flow (RF) that was fundamental to Perelman's proof of the Poincare conjecture. Analytic applications of RF can be found in many fields including general relativity and mathematics. Numerically it has been applied broadly to communication networks, medical physics, computer design and more. In this paper, we use Regge calculus (RC) to provide the first geometric discretization of the Ric. This result is fundamental for higher dimensional generalizations of discrete RF. We construct this tensor on both the simplicial lattice and its dual and prove their equivalence. We show that the Ric is an edge-based weighted average of deficit divided by an edge-based weighted average of dual area-an expression similar to the vertex-based weighted average of the scalar curvature reported recently. We use this Ric in a third and independent geometric derivation of the RC Einstein tensor in arbitrary dimensions.

The simplicial Ricci tensor

Science.gov (United States)

Alsing, Paul M.; McDonald, Jonathan R.; Miller, Warner A.

2011-08-01

The Ricci tensor (Ric) is fundamental to Einstein's geometric theory of gravitation. The three-dimensional Ric of a spacelike surface vanishes at the moment of time symmetry for vacuum spacetimes. The four-dimensional Ric is the Einstein tensor for such spacetimes. More recently, the Ric was used by Hamilton to define a nonlinear, diffusive Ricci flow (RF) that was fundamental to Perelman's proof of the Poincarè conjecture. Analytic applications of RF can be found in many fields including general relativity and mathematics. Numerically it has been applied broadly to communication networks, medical physics, computer design and more. In this paper, we use Regge calculus (RC) to provide the first geometric discretization of the Ric. This result is fundamental for higher dimensional generalizations of discrete RF. We construct this tensor on both the simplicial lattice and its dual and prove their equivalence. We show that the Ric is an edge-based weighted average of deficit divided by an edge-based weighted average of dual area—an expression similar to the vertex-based weighted average of the scalar curvature reported recently. We use this Ric in a third and independent geometric derivation of the RC Einstein tensor in arbitrary dimensions.

Practical examples of how knowledge management is addressed in Point Lepreau heat transport ageing management programs

International Nuclear Information System (INIS)

Slade, J.; Gendron, T.; Greenlaw, G.

2009-01-01

In the mid-1990s, New Brunswick Power Nuclear implemented a Management System Process Model at the Point Lepreau Generating Station that provides the basic elements of a knowledge management program. As noted by the IAEA, the challenge facing the nuclear industry now is to make improvements in knowledge management in areas that are more difficult to implement. Two of these areas are: increasing the value of existing knowledge, and converting tacit knowledge to explicit knowledge (knowledge acquisition). This paper describes some practical examples of knowledge management improvements in the Point Lepreau heat transport system ageing management program. (author)

Topological Signals of Singularities in Ricci Flow

Directory of Open Access Journals (Sweden)

Paul M. Alsing

2017-08-01

Full Text Available We implement methods from computational homology to obtain a topological signal of singularity formation in a selection of geometries evolved numerically by Ricci flow. Our approach, based on persistent homology, produces precise, quantitative measures describing the behavior of an entire collection of data across a discrete sample of times. We analyze the topological signals of geometric criticality obtained numerically from the application of persistent homology to models manifesting singularities under Ricci flow. The results we obtain for these numerical models suggest that the topological signals distinguish global singularity formation (collapse to a round point from local singularity formation (neckpinch. Finally, we discuss the interpretation and implication of these results and future applications.

Steam generators secondary side chemical cleaning at Point Lepreau using the Siemen's high temperature process

International Nuclear Information System (INIS)

Verma, K.; MacNeil, C.; Odar, S.

1996-01-01

The secondary sides of all four steam generators at the Point Lepreau Nuclear Generating Stations were cleaned during the 1995 annual outage run-down using the Siemens high temperature chemical cleaning process. Traditionally all secondary side chemical cleaning exercises in CANDU as well as the other nuclear power stations in North America have been conducted using a process developed in conjunction with the Electric Power Research Institute (EPRI). The Siemens high temperature process was applied for the first time in North America at the Point Lepreau Nuclear Generating Station (PLGS). The paper discusses experiences related to the pre and post award chemical cleaning activities, chemical cleaning application, post cleaning inspection results and waste handling activities. (author)

Almost Kaehler Ricci Flows and Einstein and Lagrange-Finsler Structures on Lie Algebroids

CERN Document Server

Vacaru, Sergiu I

2015-01-01

In this work we investigate Ricci flows of almost Kaehler structures on Lie algebroids when the fundamental geometric objects are completely determined by (semi) Riemannian metrics, or effective) regular generating Lagrange/ Finsler, functions. There are constructed canonical almost symplectic connections for which the geometric flows can be represented as gradient ones and characterized by nonholonomic deformations of Grigory Perelman's functionals. The first goal of this paper is to define such thermodynamical type values and derive almost K\\"ahler - Ricci geometric evolution equations. The second goal is to study how fixed Lie algebroid, i.e. Ricci soliton, configurations can be constructed for Riemannian manifolds and/or (co) tangent bundles endowed with nonholonomic distributions modelling (generalized) Einstein or Finsler - Cartan spaces. Finally, there are provided some examples of generic off-diagonal solutions for Lie algebroid type Ricci solitons and (effective) Einstein and Lagrange-Finsler algebro...

Possible refurbishment of Point Lepreau

International Nuclear Information System (INIS)

White, R.M.; Groom, S.H.; Thompson, P.D.; Barclay, J.M.; Allen, P.J.

2001-01-01

In February 2000, the NB Power Board of Directors approved Phase one of a project to produce a business case including a detailed scope and estimate associated with the possible refurbishment of the Point Lepreau Generating Station (PLGS). The Preliminary plan for refurbishment projects an 18-month outage starting as early as the spring of 2006. If the station were to be refurbished, then it would be run for another 25 to 30 years. The decision on whether or not to refurbish PLGS has not been made and is not expected until the summer of 2002. The results of the first phase of the project will be used to prepare a detailed business case that will be presented to the NB Power board of directors in January of 2002. At that time a decision will be made as to whether to refurbish the unit, or obtain other means of replacing the energy produced by PLGS. The station currently produces about a third of the power generated within the province. If the business case is approved, all-380 Pressure Tubes and Calandria Tubes, along with their related End Fittings and Feeders would be replaced. This material would be stored in new storage vaults to be constructed at the existing on-site Waste Management Facility. Replacement of other station components will be performed as required, as determined from the results of a comprehensive Plant Condition Assessment. The condition assessments build on work done under the Plant Life Management Program. Point Lepreau Generating Station has operated well since start of commercial operation in early 1983. With a lifetime capacity factor of about 84% (up to the end of 2000), it has proven to be an economic and environmentally sound electricity provider. The station has also had a significant positive economic impact in Southern New Brunswick, employing over 600 people. However the Pressure Tubes and Feeders are nearing the point in time in which they will exceed their fitness for service criteria. Although tubes can be replaced on an

Possible refurbishment of Point Lepreau

International Nuclear Information System (INIS)

White, R.M.; Groom, S.H.; Thompson, P.D.; Barclay, J.M.; Allen, P.J.

2001-01-01

In February 2000, the NB Power Board of Directors approved Phase one of a project to produce a business case including a detailed scope and estimate associated with the possible refurbishment of the Point Lepreau Generating Station (PLGS). The Preliminary plan for refurbishment projects an 18-month outage starting as early as the spring of 2006. If the station were to be refurbished, then it would be run for another 25 to 30 years. The decision on whether or not to refurbish PLGS has not been made and is not expected until the summer of 2002. The results of the first phase of the project will be used to prepare a detailed business case that will be presented to the NB Power board of directors in January of 2002. At that time a decision will be made as to whether to refurbish the unit, or obtain other means of replacing the energy produced by PLGS. The station currently produces about a third of the power generated within the province. If the business case is approved, all-380 Pressure Tubes and Calandria Tubes, along with their related End Fittings and Feeders would be replaced. This material would be stored in new storage vaults to be constructed at the existing on-site Waste Management Facility. Replacement of other station components will be performed as required, as determined from the results of a comprehensive Plant Condition Assessment. The condition assessments build on work done under the Plant Life Management Program. Point Lepreau Generating Station has operated well since start of commercial operation in early 1983. With a lifetime capacity factor of about 84% (up to the end of 2000), it has proven to be an economic and environmentally sound electricity provider. The station has also had a significant positive economic impact in Southern New Brunswick, employing over 600 people. However the Pressure Tubes and Feeders are nearing the point in time in which they will exceed their fitness for service criteria. Although tubes can be replaced on an

Shape signature based on Ricci flow and optimal mass transportation

Science.gov (United States)

Luo, Wei; Su, Zengyu; Zhang, Min; Zeng, Wei; Dai, Junfei; Gu, Xianfeng

2014-11-01

A shape signature based on surface Ricci flow and optimal mass transportation is introduced for the purpose of surface comparison. First, the surface is conformally mapped onto plane by Ricci flow, which induces a measure on the planar domain. Second, the unique optimal mass transport map is computed that transports the new measure to the canonical measure on the plane. The map is obtained by a convex optimization process. This optimal transport map encodes all the information of the Riemannian metric on the surface. The shape signature consists of the optimal transport map, together with the mean curvature, which can fully recover the original surface. The discrete theories of surface Ricci flow and optimal mass transportation are explained thoroughly. The algorithms are given in detail. The signature is tested on human facial surfaces with different expressions accquired by structured light 3-D scanner based on phase-shifting method. The experimental results demonstrate the efficiency and efficacy of the method.

New Li-Yau-Hamilton Inequalities for the Ricci Flow via the Space-Time Approach

OpenAIRE

Chow, Bennett; Knopf, Dan

2002-01-01

We generalize Hamilton's matrix Li-Yau-type Harnack estimate for the Ricci flow by considering the space of all LYH (Li-Yau-Hamilton) quadratics that arise as curvature tensors of space-time connections satisfying the Ricci flow with respect to the natural space-time degenerate metric. As a special case, we employ scaling arguments to derive a linear-type matrix LYH estimate. The new LYH quadratics obtained in this way are associated to the system of the Ricci flow coupled to a 1-form and a 2...

Visuaalantropoloogia - inimlik mõõde asjade maailmas / Jay Ruby ; interv. Peeter Linnap

Index Scriptorium Estoniae

Ruby, Jay

2006-01-01

Ameerika visuaalkultuuri teoreetik Jay Ruby on paari viimase aastakümne jooksul keskendunud pildilise kommunikatsiooni etnograafilisele käsitlemisele Ameerika maaühiskonnas. Peeter Linnapi intervjuu Jay Rubyga Tartu Kõrgemas Kunstikoolis 23. V

Topologically massive gravity and Ricci-Cotton flow

Energy Technology Data Exchange (ETDEWEB)

Lashkari, Nima; Maloney, Alexander, E-mail: lashkari@physics.mcgill.ca, E-mail: maloney@physics.mcgill.ca [McGill Physics Department, 3600 rue University, Montreal, QC H3A 2T8 (Canada)

2011-05-21

We consider topologically massive gravity (TMG), which is three-dimensional general relativity with a cosmological constant and a gravitational Chern-Simons term. When the cosmological constant is negative the theory has two potential vacuum solutions: anti-de Sitter space and warped anti-de Sitter space. The theory also contains a massive graviton state which renders these solutions unstable for certain values of the parameters and boundary conditions. We study the decay of these solutions due to the condensation of the massive graviton mode using Ricci-Cotton flow, which is the appropriate generalization of Ricci flow to TMG. When the Chern-Simons coupling is small the AdS solution flows to warped AdS by the condensation of the massive graviton mode. When the coupling is large the situation is reversed, and warped AdS flows to AdS. Minisuperspace models are constructed where these flows are studied explicitly.

Topologically massive gravity and Ricci-Cotton flow

International Nuclear Information System (INIS)

Lashkari, Nima; Maloney, Alexander

2011-01-01

We consider topologically massive gravity (TMG), which is three-dimensional general relativity with a cosmological constant and a gravitational Chern-Simons term. When the cosmological constant is negative the theory has two potential vacuum solutions: anti-de Sitter space and warped anti-de Sitter space. The theory also contains a massive graviton state which renders these solutions unstable for certain values of the parameters and boundary conditions. We study the decay of these solutions due to the condensation of the massive graviton mode using Ricci-Cotton flow, which is the appropriate generalization of Ricci flow to TMG. When the Chern-Simons coupling is small the AdS solution flows to warped AdS by the condensation of the massive graviton mode. When the coupling is large the situation is reversed, and warped AdS flows to AdS. Minisuperspace models are constructed where these flows are studied explicitly.

Nonsmooth differential geometry-an approach tailored for spaces with Ricci curvature bounded from below

CERN Document Server

Gigli, Nicola

2018-01-01

The author discusses in which sense general metric measure spaces possess a first order differential structure. Building on this, spaces with Ricci curvature bounded from below a second order calculus can be developed, permitting the author to define Hessian, covariant/exterior derivatives and Ricci curvature.

Wind hazard assessment for Point Lepreau Generating Station

International Nuclear Information System (INIS)

Mullin, D.; Moland, M.; Sciaudone, J.C.; Twisdale, L.A.; Vickery, P.J.; Mizzen, D.R.

2015-01-01

In response to the CNSC Fukushima Action Plan, NB Power has embarked on a wind hazard assessment for the Point Lepreau Generating Station site that incorporates the latest up to date wind information and modeling. The objective was to provide characterization of the wind hazard from all potential sources and estimate wind-driven missile fragilities and wind pressure fragilities for various structures, systems and components that would provide input to a possible high wind Probabilistic Safety Assessment. The paper will discuss the overall methodology used to assess hazards related to tornadoes, hurricanes and straight-line winds, and site walk-down and hazard/fragility results. (author)

Scattering of Ricci scalar perturbations from Schwarzschild black holes in modified gravity

Energy Technology Data Exchange (ETDEWEB)

Sibandze, Dan B.; Goswami, Rituparno; Maharaj, Sunil D.; Nzioki, Anne Marie [University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics Statistics and Computer Science, Private Bag X54001, Durban (South Africa); Dunsby, Peter K.S. [University of Cape Town, Department of Mathematics and Applied Mathematics and ACGC, Cape Town (South Africa)

2017-06-15

It has already been shown that the gravitational waves emitted from a Schwarzschild black hole in f(R) gravity have no signatures of the modification of gravity from General Relativity, as the Regge-Wheeler equation remains invariant. In this paper we consider the perturbations of Ricci scalar in a vacuum Schwarzschild spacetime, which is unique to higher order theories of gravity and is absent in General Relativity. We show that the equation that governs these perturbations can be reduced to a Volterra integral equation. We explicitly calculate the reflection coefficients for the Ricci scalar perturbations, when they are scattered by the black hole potential barrier. Our analysis shows that a larger fraction of these Ricci scalar waves are reflected compared to the gravitational waves. This may provide a novel observational signature for fourth order gravity. (orig.)

AECB staff annual report of Point Lepreau G.S. for the year 1990

International Nuclear Information System (INIS)

1991-05-01

This report is a review by AECB staff of the operation of Point Lepreau Nuclear Generating Station during 1990. The review is based on information contained in the various documents submitted by New Brunswick Power under the terms of the Operating Licence and on information gathered by AECB staff during routine site monitoring, inspections and audits

Viscous Ricci dark energy

International Nuclear Information System (INIS)

Feng Chaojun; Li Xinzhou

2009-01-01

We investigate the viscous Ricci dark energy (RDE) model by assuming that there is bulk viscosity in the linear barotropic fluid and the RDE. In the RDE model without bulk viscosity, the universe is younger than some old objects at certain redshifts. Since the age of the universe should be longer than any objects living in the universe, the RDE model suffers the age problem, especially when we consider the object APM 08279+5255 at z=3.91 with age t=2.1 Gyr. In this Letter, we find that once the viscosity is taken into account, this age problem is alleviated.

Probabilistic seismic hazard assessment for Point Lepreau Generating Station

Energy Technology Data Exchange (ETDEWEB)

Mullin, D. [New Brunswick Power Corp., Point Lepreau Generating Station, Lepreau, New Brunswick (Canada); Lavine, A. [AMEC Foster Wheeler Environment and Infrastructure Americas, Oakland, California (United States); Egan, J. [SAGE Engineers, Oakland, California (United States)

2015-09-15

A Probabilistic Seismic Hazard Assessment (PSHA) has been performed for the Point Lepreau Generating Station (PLGS). The objective is to provide characterization of the earthquake ground shaking that will be used to evaluate seismic safety. The assessment is based on the current state of knowledge of the informed scientific and engineering community regarding earthquake hazards in the site region, and includes two primary components-a seismic source model and a ground motion model. This paper provides the methodology and results of the PLGS PSHA. The implications of the updated hazard information for site safety are discussed in a separate paper. (author)

Probabilistic seismic hazard assessment for Point Lepreau Generating Station

Energy Technology Data Exchange (ETDEWEB)

Mullin, D., E-mail: dmullin@nbpower.com [New Brunswick Power Corporation, Point Lepreau Generating Station, Point Lepreau, NB (Canada); Lavine, A., E-mail: alexis.lavine@amecfw.com [AMEC Foster Wheeler Environment & Infrastructure Americas, Oakland, CA (United States); Egan, J., E-mail: jegan@sageengineers.com [SAGE Engineers, Oakland, CA (United States)

2015-07-01

A Probabilistic Seismic Hazard Assessment (PSHA) has been performed for the Point Lepreau Generating Station (PLGS). The objective is to provide characterization of the earthquake ground shaking that will be used to evaluate seismic safety. The assessment is based on the current state of knowledge of the informed scientific and engineering community regarding earthquake hazards in the site region, and includes two primary components--a seismic source model and a ground motion model. This paper provides the methodology and results of the PLGS PSHA. The implications of the updated hazard information for site safety are discussed in a separate paper. (author)

Gentilly-2 and Point Lepreau divider plate replacement

International Nuclear Information System (INIS)

Schneider, W.; McClellan, G.; Weston, S.

1996-01-01

The steam generators at Hydro Quebec's Gentilly-2 and New Brunswick Power's Point Lepreau Nuclear Plants have been in operation since 1983, and were built with primary divider plates of a bolted panel configuration. During a routine outage inspection at Gentilly-2, it was noted that two bolts had dislodged from the divider plate and were located lying in the primary head. Subsequent inspections revealed erosion damage to a a substantial number of divider plate bolts and to a lesser extent, to the divider plate itself. After further inspection and repair the units were returned to operation, however, it was determined that a permanent replacement of the primary divider plates was going to be necessary. Upon evaluation of various options, it was decided that the panel type divider plates would be replaced with a single piece floating design. The divider plate itself was to be of one piece all-welded arrangement to be constructed from individual panels to be brought in through the manways. In view of the strength limitations of the bolted attachment of the upper seat bar to the tubesheet, a new welded seat was was provided. To counteract erosion concerns, the new divider plate is fitted with erosion resistant inserts of weld buildup and with improved sealing features in order to minimize leakage and erosion. At an advanced stage in the design and manufacture of the components, the issue of divider plate strength during loss of coolant accident (LOCA) conditions came into focus. Analysis was performed to determine the strength and/or failure characteristics of the divider plate to a variety of small and large LOCA conditions. Subsequently, Point Lepreau decided to replace their divider plates to address LOCA concerns. The paper describes the diagnosis of the original divider plates and the design. manufacture, field mobilization, installation and subsequent operation of the replacement divider plates. (author)

Strategy for success in maintenance management at Point Lepreau nuclear generating station

International Nuclear Information System (INIS)

White, R.M.

1987-01-01

Improvements in availability of the station and in productivity of workers were achieved at Point Lepreau Nuclear Generating Station through implementation of a Maintenance Management System, which incorporates work planning and outage management techniques. Eight software systems on a VAX 11/70 minicomputer control work orders, temporary and permanent design changes, parts and material inventories, time keeping, and project management. All maintenance is coordinated through a regular planning meeting

Re-caching by Western scrub-jays (Aphelocoma californica cannot be attributed to stress.

Directory of Open Access Journals (Sweden)

James M Thom

Full Text Available Western scrub-jays (Aphelocoma californica live double lives, storing food for the future while raiding the stores of other birds. One tactic scrub-jays employ to protect stores is "re-caching"-relocating caches out of sight of would-be thieves. Recent computational modelling work suggests that re-caching might be mediated not by complex cognition, but by a combination of memory failure and stress. The "Stress Model" asserts that re-caching is a manifestation of a general drive to cache, rather than a desire to protect existing stores. Here, we present evidence strongly contradicting the central assumption of these models: that stress drives caching, irrespective of social context. In Experiment (i, we replicate the finding that scrub-jays preferentially relocate food they were watched hiding. In Experiment (ii we find no evidence that stress increases caching. In light of our results, we argue that the Stress Model cannot account for scrub-jay re-caching.

Environmental radiation monitoring data for Point Lepreau Generating Station, 1988. Annual publication

Energy Technology Data Exchange (ETDEWEB)

Sutherland, J K

1989-01-01

Annual report presenting a compilation of the 1988 environmental radiation monitoring program data from samples collected around the Point Lepreau Nuclear Generating Station (PLNGS) and at reference stations remote from PLNGS. About 1,700 analyses were made on 1,200 samples to monitor environmental radiation, including air filters, airborne water vapour, sea water, well water, milk, beach sediments, clams, fish, lobster, dulse, crabs, scallops and lichen. Background radiation is measured by thermoluminescence dosimetry.

Environmental radiation monitoring data for Point Lepreau Generating Station, 1987. Annual publication

Energy Technology Data Exchange (ETDEWEB)

Sutherland, J K

1988-01-01

Annual report presenting a compilation of the 1987 environmental radiation monitoring program data from samples collected around the Point Lepreau Nuclear Generating Station (PLNGS) and at reference stations remote from PLNGS. About 1,800 analyses were made on 1,300 samples to monitor environmental radiation, including air filters, airborne water vapour, sea water, well water, milk, beach sediments, clams, fish, lobster, dulse, crabs, scallops and periwinkles. Background radiation is measured by thermoluminescence dosimetry.

Discrete Ricci Flow in Higher Dimensions

Science.gov (United States)

2015-02-01

recently, we showed analytically that the SRF equations converged to the continuum RF equations for the neck-pinch 3- geometry [10]. In this analysis we also...Hamilton’s RF. It is the first dimensionally agnostic generalization of RF for PL geometries . We refer to our approach as simplicial Ricci flow (SRF). For a...Discrete Exterior Calculus , Regge Calculus , Piecewise Linear Complex 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18. NUMBER

Conformal Collineations of the Ricci and Energy-Momentum Tensors in Static Plane Symmetric Space-Times

Science.gov (United States)

Akhtar, S. S.; Hussain, T.; Bokhari, A. H.; Khan, F.

2018-04-01

We provide a complete classification of static plane symmetric space-times according to conformal Ricci collineations (CRCs) and conformal matter collineations (CMCs) in both the degenerate and nondegenerate cases. In the case of a nondegenerate Ricci tensor, we find a general form of the vector field generating CRCs in terms of unknown functions of t and x subject to some integrability conditions. We then solve the integrability conditions in different cases depending upon the nature of the Ricci tensor and conclude that the static plane symmetric space-times have a 7-, 10- or 15-dimensional Lie algebra of CRCs. Moreover, we find that these space-times admit an infinite number of CRCs if the Ricci tensor is degenerate. We use a similar procedure to study CMCs in the case of a degenerate or nondegenerate matter tensor. We obtain the exact form of some static plane symmetric space-time metrics that admit nontrivial CRCs and CMCs. Finally, we present some physical applications of our obtained results by considering a perfect fluid as a source of the energy-momentum tensor.

Quasi-topological Ricci polynomial gravities

Science.gov (United States)

Li, Yue-Zhou; Liu, Hai-Shan; Lü, H.

2018-02-01

Quasi-topological terms in gravity can be viewed as those that give no contribution to the equations of motion for a special subclass of metric ansätze. They therefore play no rôle in constructing these solutions, but can affect the general perturbations. We consider Einstein gravity extended with Ricci tensor polynomial invariants, which admits Einstein metrics with appropriate effective cosmological constants as its vacuum solutions. We construct three types of quasi-topological gravities. The first type is for the most general static metrics with spherical, toroidal or hyperbolic isometries. The second type is for the special static metrics where g tt g rr is constant. The third type is the linearized quasitopological gravities on the Einstein metrics. We construct and classify results that are either dependent on or independent of dimensions, up to the tenth order. We then consider a subset of these three types and obtain Lovelock-like quasi-topological gravities, that are independent of the dimensions. The linearized gravities on Einstein metrics on all dimensions are simply Einstein and hence ghost free. The theories become quasi-topological on static metrics in one specific dimension, but non-trivial in others. We also focus on the quasi-topological Ricci cubic invariant in four dimensions as a specific example to study its effect on holography, including shear viscosity, thermoelectric DC conductivities and butterfly velocity. In particular, we find that the holographic diffusivity bounds can be violated by the quasi-topological terms, which can induce an extra massive mode that yields a butterfly velocity unbound above.

Operational reliability of the Point Lepreau GS standby generators

Energy Technology Data Exchange (ETDEWEB)

Loughead, D. A.; McGregor, A. T. [Safety and Compllance Group, New Brunswick Electric Power Commission, Point Lepreau Generating Station, P.O.Box 10 Lepreau, New Brunswick E0G 2H0 (Canada)

1986-02-15

Performance of the two Point Lepreau GS standby generators during the first three years of licensed station operation is reviewed. It is shown that the mandated reliability/availability requirements have been met. The nature of starting and running failures has been examined and the consequences, in terms of design and procedural changes, discussed. A brief review of standby generator outages is included to permit estimates of standby generator availability and total Class III standby power unavailability. A pair of simple equations is introduced as a means of estimating the probable economic penalty, both cumulative and incremental, associated with the running failure of one standby generator while the other is on a maintenance outage. (authors)

Operational reliability of the Point Lepreau GS standby generators

International Nuclear Information System (INIS)

Loughead, D.A.; McGregor, A.T.

1986-01-01

Performance of the two Point Lepreau GS standby generators during the first three years of licensed station operation is reviewed. It is shown that the mandated reliability/availability requirements have been met. The nature of starting and running failures has been examined and the consequences, in terms of design and procedural changes, discussed. A brief review of standby generator outages is included to permit estimates of standby generator availability and total Class III standby power unavailability. A pair of simple equations is introduced as a means of estimating the probable economic penalty, both cumulative and incremental, associated with the running failure of one standby generator while the other is on a maintenance outage. (authors)

Ricci dark energy in Chern-Simons modified gravity

Energy Technology Data Exchange (ETDEWEB)

Silva, J.G.; Santos, A.F. [Universidade Federal de Mato Grosso (UFMT), Campo Grande, MT (Brazil)

2013-07-01

Full text: Currently the accelerated expansion of the universe has been strongly confirmed by some independent experiments such as the Cosmic Microwave Background Radiation (CMBR) and Sloan Digital Sky Survey (SDSS). In an attempt to explain this phenomenon there are two possible paths; first option - propose corrections to general relativity, second option - assuming that there is a dominant component of the universe, a kind of antigravity called dark energy. Any way that we intend to follow, there are numerous models that attempt to explain this effect. One of the models of modified gravity that has stood out in recent years is the Chern-Simons modified gravity. This modification consists in the addition of the Pontryagin density, which displays violation of parity symmetry in Einstein-Hilbert action. From among the various models proposed for dark energy there are some that are based on the holographic principle, known as holographic dark energy. Such models are based on the idea that the energy density of a given system is proportional to the inverse square of some characteristic length of the system. From these studies, here we consider the model proposed by Gao et. al., a model of dark energy where the characteristic length is given by the average radius of the Ricci scalar. Thus, the dark energy density is proportional to the Ricci scalar, i.e., ρ{sub x} ∝ R. It is a phenomenologically viable model and displays results similar to that presented by the cosmological model ACDM. In this work, we have considered the Ricci dark energy model in the dynamic Chern-Simons modified gravity. We show that in this context the evolution of the scale factor is similar to that displayed by the modified Chaplygin gas. (author)

Ricci dark energy in Chern-Simons modified gravity

International Nuclear Information System (INIS)

Silva, J.G.; Santos, A.F.

2013-01-01

Full text: Currently the accelerated expansion of the universe has been strongly confirmed by some independent experiments such as the Cosmic Microwave Background Radiation (CMBR) and Sloan Digital Sky Survey (SDSS). In an attempt to explain this phenomenon there are two possible paths; first option - propose corrections to general relativity, second option - assuming that there is a dominant component of the universe, a kind of antigravity called dark energy. Any way that we intend to follow, there are numerous models that attempt to explain this effect. One of the models of modified gravity that has stood out in recent years is the Chern-Simons modified gravity. This modification consists in the addition of the Pontryagin density, which displays violation of parity symmetry in Einstein-Hilbert action. From among the various models proposed for dark energy there are some that are based on the holographic principle, known as holographic dark energy. Such models are based on the idea that the energy density of a given system is proportional to the inverse square of some characteristic length of the system. From these studies, here we consider the model proposed by Gao et. al., a model of dark energy where the characteristic length is given by the average radius of the Ricci scalar. Thus, the dark energy density is proportional to the Ricci scalar, i.e., ρ x ∝ R. It is a phenomenologically viable model and displays results similar to that presented by the cosmological model ACDM. In this work, we have considered the Ricci dark energy model in the dynamic Chern-Simons modified gravity. We show that in this context the evolution of the scale factor is similar to that displayed by the modified Chaplygin gas. (author)

Holographic reconstruction and renormalization in asymptotically Ricci-flat spacetimes

NARCIS (Netherlands)

Caldeira Costa, R.N.

2012-01-01

In this work we elaborate on an extension of the AdS/CFT framework to a sub-class of gravitational theories with vanishing cosmological constant. By building on earlier ideas, we construct a correspondence between Ricci-flat spacetimes admitting asymptotically hyperbolic hypersurfaces and a family

Formal matched asymptotics for degenerate Ricci flow neckpinches

International Nuclear Information System (INIS)

Angenent, Sigurd B; Isenberg, James; Knopf, Dan

2011-01-01

Gu and Zhu (2008 Commun. Anal. Geom. 16 467–94) have shown that type-II Ricci flow singularities develop from nongeneric rotationally symmetric Riemannian metrics on S n+1 (n≥2). In this paper, we describe and provide plausibility arguments for a detailed asymptotic profile and rate of curvature blow-up that we predict such solutions exhibit

Environmental radiation monitoring data for Point Lepreau Generating Station, 1990. Annual publication

Energy Technology Data Exchange (ETDEWEB)

Sutherland, J K

1991-01-01

Annual report presenting a compilation of the 1990 environmental radiation monitoring program data from samples collected around the Point Lepreau Nuclear Generating Station (PLNGS) and at reference stations remote from PLNGS. About 1,500 analyses were made on 1,100 samples to monitor environmental radiation, including air particulates, airborne water vapour, carbon dioxide in air, sea water, well water, milk, beach sediments, clams, fish, lobster, dulse, crabs, scallops, periwinkles, sea plants and lichen. Background radiation is measured by thermoluminescence dosimetry. Radon is not assessed.

Experience from the development of Point Lepreau's training program for technical support staff

International Nuclear Information System (INIS)

Turner, S.; Scott, K.

2007-01-01

The Training Department at the Point Lepreau GS has been developing and improving its training for technical support staff. A generic set of objectives are being used as the basis for a systematic approach to training. The program covers general and job specific knowledge and skills using a mix of classroom instruction, mentoring and continuing training seminars. This paper describes experience, success and the challenges in the development, delivery and evaluation of the training program. (author)

Bedrock Geologic Map of the Jay Peak, VT Quadrangle

Data.gov (United States)

Vermont Center for Geographic Information — Digital data from VG99-1 Compilation bedrock geologic map of the Jay Peak quadrangle, Compiled by B. Doolan, 1999: VGS Open-File Report VG99-1, 1 plate, scale...

A Markov decision process for managing habitat for Florida scrub-jays

Science.gov (United States)

Johnson, Fred A.; Breininger, David R.; Duncan, Brean W.; Nichols, James D.; Runge, Michael C.; Williams, B. Ken

2011-01-01

Florida scrub-jays Aphelocoma coerulescens are listed as threatened under the Endangered Species Act due to loss and degradation of scrub habitat. This study concerned the development of an optimal strategy for the restoration and management of scrub habitat at Merritt Island National Wildlife Refuge, which contains one of the few remaining large populations of scrub-jays in Florida. There are documented differences in the reproductive and survival rates of scrubjays among discrete classes of scrub height (strategy that would maximize the long-term growth rate of the resident scrub-jay population. We used aerial imagery with multistate Markov models to estimate annual transition probabilities among the four scrub-height classes under three possible management actions: scrub restoration (mechanical cutting followed by burning), a prescribed burn, or no intervention. A strategy prescribing the optimal management action for management units exhibiting different proportions of scrub-height classes was derived using dynamic programming. Scrub restoration was the optimal management action only in units dominated by mixed and tall scrub, and burning tended to be the optimal action for intermediate levels of short scrub. The optimal action was to do nothing when the amount of short scrub was greater than 30%, because short scrub mostly transitions to optimal height scrub (i.e., that state with the highest demographic success of scrub-jays) in the absence of intervention. Monte Carlo simulation of the optimal policy suggested that some form of management would be required every year. We note, however, that estimates of scrub-height transition probabilities were subject to several sources of uncertainty, and so we explored the management implications of alternative sets of transition probabilities. Generally, our analysis demonstrated the difficulty of managing for a species that requires midsuccessional habitat, and suggests that innovative management tools may be needed to

Start-up support for New Brunswick Electric's Point Lepreau nuclear steam generators

International Nuclear Information System (INIS)

Schneider, W.; Leroux, A.

1983-05-01

The start-up of the 600 MW Point Lepreau reactor provided the opportunity for direct involvement in the important low and medium power start-up phase which was of particular interest because this was a first-of-a-kind reactor type incorporating a new steam generator design. Support included test assistance and test results interpretation for the thermal hydraulic performance of the steam generators and in particular, investigation of water level response to operating pressure, power and feed flow. This work resulted in both a greatly improved understanding of transient characteristics and in a number of beneficial refinements in the control methods

Western scrub-jays allocate longer observation time to more valuable information.

Science.gov (United States)

Watanabe, Arii; Grodzinski, Uri; Clayton, Nicola S

2014-07-01

When humans mentally reconstruct past events and imagine future scenarios, their subjective experience of mentally time travelling is accompanied by the awareness of doing so. Despite recent popularity of studying episodic memory in animals, such phenomenological consciousness has been extremely difficult to demonstrate without agreed behavioural markers of consciousness in non-linguistic subjects. We presented western scrub-jays (Aphelocoma californica) with a task requiring them to allocate observing time between two peepholes to see food being hidden in either of two compartments, one where observing the hiding location was necessary to later relocate the food, and another where food could easily be found without watching. Jays first separately experienced these consequences of possessing information in each compartment and subsequently, once given a choice, made more looks and spent more time looking into the compartment where information was necessary than into the compartment where it was unnecessary. Thus, the jays can collect information to solve a future problem. Moreover, they can differentiate sources of information according to their potential value and modify behaviour to efficiently collect important, usable information. This is the first evidence of metacognition in a species that passes the behavioural criteria for both retrospective and prospective mental time travel.

Update of severe accident management guidelines at Point Lepreau Generating Station

Energy Technology Data Exchange (ETDEWEB)

Mullin, D.; Robertson, S., E-mail: dmullin@nbpower.com, E-mail: srobertson@nbpower.com [New Brunswick Power Corporation, Point Lepreau Generating Station, NB (Canada); Wilson, D.J., E-mail: wilsondj@nbnet.nb.ca [Atlantic Nuclear Inc., Fredericton, NB (Canada)

2015-07-01

In response to the events at Fukushima Dai'ichi, the CANDU Owners Group (COG) embarked on Joint Project JP4426 to update the overall framework for Severe Accident Management Guidelines (SAMG) to reflect lessons learned. This includes enhancements to consider SAMG in the shutdown/low power state, more extensive consideration of Spent (Irradiated) Fuel Bay (SFB) events and to address plant habitability issues. Point Lepreau is in the process of applying the COG methodologies in developing site-specific basis documents and revisions to SAM guidance documents. The paper will also describe SAMG for the Canister site, emergency procedure revisions to deal with extreme natural events and recommendations for evacuation of protective zones based on plant state criteria. (author)

Eurasian jays do not copy the choices of conspecifics, but they do show evidence of stimulus enhancement

Directory of Open Access Journals (Sweden)

Rachael Miller

2016-12-01

Full Text Available Corvids (birds in the crow family are hypothesised to have a general cognitive tool-kit because they show a wide range of transferrable skills across social, physical and temporal tasks, despite differences in socioecology. However, it is unknown whether relatively asocial corvids differ from social corvids in their use of social information in the context of copying the choices of others, because only one such test has been conducted in a relatively asocial corvid. We investigated whether relatively asocial Eurasian jays (Garrulus glandarius use social information (i.e., information made available by others. Previous studies have indicated that jays attend to social context in their caching and mate provisioning behaviour; however, it is unknown whether jays copy the choices of others. We tested the jays in two different tasks varying in difficulty, where social corvid species have demonstrated social information use in both tasks. Firstly, an object-dropping task was conducted requiring objects to be dropped down a tube to release a food reward from a collapsible platform, which corvids can learn through explicit training. Only one rook and one New Caledonian crow have learned the task using social information from a demonstrator. Secondly, we tested the birds on a simple colour discrimination task, which should be easy to solve, because it has been shown that corvids can make colour discriminations. Using the same colour discrimination task in a previous study, all common ravens and carrion crows copied the demonstrator. After observing a conspecific demonstrator, none of the jays solved the object-dropping task, though all jays were subsequently able to learn to solve the task in a non-social situation through explicit training, and jays chose the demonstrated colour at chance levels. Our results suggest that social and relatively asocial corvids differ in social information use, indicating that relatively asocial species may have

Radiating c metric: an example of a proper Ricci Collineation

International Nuclear Information System (INIS)

Aulestia, L.; Nunez, L.; Patino, A.; Rago, H.; Herrera, L.

1984-01-01

A generalization of the charged c metric to the nonstationary case is given. The possibility of associating the energy-momentum tensor with the electromagnetic or neutrino field is discussed. It is shown that, for a specific choice of the time-dependent parameters, the metric admits at least a two-parameter group of proper Ricci collineations

AECB staff annual report of Point Lepreau NGS for the year 1991

International Nuclear Information System (INIS)

1992-11-01

This report is the Atomic Energy Control Board (AECB) assessment of the operation of Point Lepreau nuclear generating station during 1991. On-site project officers and Ottawa-based specialists monitored the plant throughout the year. The AECB believes that New Brunswick Power is operating the reactor safely and in accordance with its operating licence. New Brunswick Power have made good progress with changes to make sure the special safety systems are operated to the highest possible standards. NB Power's financial restraints have not affected safe operation of the reactor; however, limited resources and an ambitious program of support for the first Romanian reactor could affect future operation

Spacetimes of Weyl and Ricci type N in higher dimensions

Czech Academy of Sciences Publication Activity Database

Kuchynka, M.; Pravdová, Alena

2016-01-01

Roč. 33, č. 11 (2016), s. 115006 ISSN 0264-9381 R&D Projects: GA ČR GB14-37086G Institutional support: RVO:67985840 Keywords : Weyl type N * Ricci type N * higher dimensions Subject RIV: BA - General Mathematics Impact factor: 3.119, year: 2016 http://iopscience.iop.org/article/10.1088/0264-9381/33/11/115006

Ricci time in the Lemaître-Tolman model and the block universe

Science.gov (United States)

Elmahalawy, Yasser; Hellaby, Charles; Ellis, George F. R.

2015-10-01

It is common to think of our universe according to the "block universe" concept, which says that spacetime consists of many "stacked" three-surfaces, labelled by some kind of proper time, . Standard ideas do not distinguish past and future, but Ellis' "evolving block universe" tries to make a fundamental distinction. One proposal for this proper time is the proper time measured along the timelike Ricci eigenlines, starting from the big bang. This work investigates the shape of the "Ricci time" surfaces relative to the the null surfaces. We use the Lemaître-Tolman metric as our inhomogeneous spacetime model, and we find the necessary and sufficient conditions for these constant surfaces, , to be spacelike or timelike. Furthermore, we look at the effect of strong gravity domains by determining the location of timelike S regions relative to apparent horizons. We find that constant Ricci time surfaces are always spacelike near the big bang, while at late times (near the crunch or the extreme far future), they are only timelike under special circumstances. At intermediate times, timelike S regions are common unless the variation of the bang time is restricted. The regions where these surfaces become timelike are often adjacent to apparent horizons, but always outside them, and in particular timelike S regions do not occur inside the horizons of black-hole-like models.

Rigidity of complete generic shrinking Ricci solitons

Science.gov (United States)

Chu, Yawei; Zhou, Jundong; Wang, Xue

2018-01-01

Let (Mn , g , X) be a complete generic shrinking Ricci soliton of dimension n ≥ 3. In this paper, by employing curvature inequalities, the formula of X-Laplacian for the norm square of the trace-free curvature tensor, the weak maximum principle and the estimate of the scalar curvature of (Mn , g) , we prove some rigidity results for (Mn , g , X) . In particular, it is showed that (Mn , g , X) is isometric to Rn or a finite quotient of Sn under a pointwise pinching condition. Moreover, we establish several optimal inequalities and classify those shrinking solitons for equalities.

A Markov decision process for managing habitat for Florida scrub-jays

Science.gov (United States)

Johnson, Fred A.; Breininger, David R.; Duncan, Brean W.; Nichols, James D.; Runge, Michael C.; Williams, B. Ken

2011-01-01

Florida scrub-jays Aphelocoma coerulescens are listed as threatened under the Endangered Species Act due to loss and degradation of scrub habitat. This study concerned the development of an optimal strategy for the restoration and management of scrub habitat at Merritt Island National Wildlife Refuge, which contains one of the few remaining large populations of scrub-jays in Florida. There are documented differences in the reproductive and survival rates of scrubjays among discrete classes of scrub height (Markov models to estimate annual transition probabilities among the four scrub-height classes under three possible management actions: scrub restoration (mechanical cutting followed by burning), a prescribed burn, or no intervention. A strategy prescribing the optimal management action for management units exhibiting different proportions of scrub-height classes was derived using dynamic programming. Scrub restoration was the optimal management action only in units dominated by mixed and tall scrub, and burning tended to be the optimal action for intermediate levels of short scrub. The optimal action was to do nothing when the amount of short scrub was greater than 30%, because short scrub mostly transitions to optimal height scrub (i.e., that state with the highest demographic success of scrub-jays) in the absence of intervention. Monte Carlo simulation of the optimal policy suggested that some form of management would be required every year. We note, however, that estimates of scrub-height transition probabilities were subject to several sources of uncertainty, and so we explored the management implications of alternative sets of transition probabilities. Generally, our analysis demonstrated the difficulty of managing for a species that requires midsuccessional habitat, and suggests that innovative management tools may be needed to help ensure the persistence of scrub-jays at Merritt Island National Wildlife Refuge. The development of a tailored monitoring

On black holes in multidimensional theory with Ricci-flat internal spaces

OpenAIRE

Fadeev, S. B.; Ivashchuk, V. D.; Melnikov, V. N.

2010-01-01

A generalization of the Tangherlini solution for the case of n internal Ricci-flat spaces is obtained. It is shown that in the (2+d)-dimensional section a horizon exists only in the trivial case when the internal-space factors are constant. The p-adic analog of the solution is also considered.

L2-Harmonic Forms on Incomplete Riemannian Manifolds with Positive Ricci Curvature

Directory of Open Access Journals (Sweden)

Junya Takahashi

2018-05-01

Full Text Available We construct an incomplete Riemannian manifold with positive Ricci curvature that has non-trivial L 2 -harmonic forms and on which the L 2 -Stokes theorem does not hold. Therefore, a Bochner-type vanishing theorem does not hold for incomplete Riemannian manifolds.

Piecewise linear manifolds: Einstein metrics and Ricci flows

International Nuclear Information System (INIS)

Schrader, Robert

2016-01-01

This article provides an attempt to extend concepts from the theory of Riemannian manifolds to piecewise linear (p.l.) spaces. In particular we propose an analogue of the Ricci tensor, which we give the name of an Einstein vector field . On a given set of p.l. spaces we define and discuss (normalized) Einstein flows. p.l. Einstein metrics are defined and examples are provided. Criteria for flows to approach Einstein metrics are formulated. Second variations of the total scalar curvature at a specific Einstein space are calculated. (paper)

Spontaneous compactification and Ricci-flat manifolds with torsion

International Nuclear Information System (INIS)

McInnes, B.

1985-06-01

The Freund-Rubin mechanism is based on the equation Rsub(ik)=lambdagsub(ik) (where lambda>0), which, via Myers' Theorem, implies ''spontaneous'' compactification. The difficulties connected with the cosmological constant in this approach can be resolved if torsion is introduced and lambda set equal to zero, but then compactification ''by hand'' is necessary, since the equation Rsub(ik)=0 can be satisfied both on compact and on non-compact manifolds. In this paper we discuss the global geometry of Ricci-flat manifolds with torsion, and suggest ways of restoring the ''spontaneity'' of the compactification. (author)

Physical and Geometric Interpretations of the Riemann Tensor, Ricci Tensor, and Scalar Curvature

OpenAIRE

Loveridge, Lee C.

2004-01-01

Various interpretations of the Riemann Curvature Tensor, Ricci Tensor, and Scalar Curvature are described. Also, the physical meanings of the Einstein Tensor and Einstein's Equations are discussed. Finally a derivation of Newtonian Gravity from Einstein's Equations is given.

Maximum Solutions of Normalized Ricci Flow on 4-Manifolds

Science.gov (United States)

Fang, Fuquan; Zhang, Yuguang; Zhang, Zhenlei

2008-10-01

We consider the maximum solution g( t), t ∈ [0, + ∞), to the normalized Ricci flow. Among other things, we prove that, if ( M, ω) is a smooth compact symplectic 4-manifold such that {b_2^+(M) > 1} and let g( t), t ∈ [0, ∞), be a solution to (1.3) on M whose Ricci curvature satisfies that |Ric( g( t))| ≤ 3 and additionally χ( M) = 3τ ( M) > 0, then there exists an {min mathbb{N}} , and a sequence of points { x j, k ∈ M}, j = 1, . . . , m, satisfying that, by passing to a subsequence, {{(M, g(tk+t), x_{1,k},ldots, x_{m,k})stackrel{d_{GH}}longrightarrow ({\\coprod limitsm_{j=1}} N_j , g_{infty}, x_{1,infty}, ldots, x_{m,infty}),}} t ∈ [0, ∞), in the m-pointed Gromov-Hausdorff sense for any sequence t k → ∞, where ( N j , g ∞), j = 1, . . . , m, are complete complex hyperbolic orbifolds of complex dimension 2 with at most finitely many isolated orbifold points. Moreover, the convergence is C ∞ in the non-singular part of {\\coprod _1^m Nj} and {text{Vol}_{g0}(M)=sum_{j=1}mtext{Vol}_{g_{infty}}(Nj)} , where χ( M) (resp. τ( M)) is the Euler characteristic (resp. signature) of M.

Bedrock geologic map of the Jay and North Troy area, Vermont

Data.gov (United States)

Vermont Center for Geographic Information — Digital Data from VG97-04C Stanley, RS, and Roy, D, 1997,�Bedrock geologic map of the Jay and North Troy area, Vermont: VGS Open-File Report VG97-04c, scale 1:24000....

Classification of the Ricci and Plebanski tensors in general relativity using Newman--Penrose formalism

International Nuclear Information System (INIS)

McIntosh, C.B.G.; Foyster, J.M.; Lun, A.W.h.

1981-01-01

A list is given of a canonical set of the Newman--Penrose quantities Phi/sub A/B, the tetrad components of the trace-free Ricci tensor, for each Plebanski class according to Plebanski's classification of this tensor. This comparative list can easily be extended to cover the classification in tetrad language of any second-order, trace-free, symmetric tensor in a space-time. A fourth-order tensor which is the product of two such tensors was defined by Plebanski and used in his classification. This has the same symmetries as the Weyl tensor. The Petrov classification of this tensor, here called the Plebanski tensor, is discussed along with the classification of the Ricci tensor. The use of the Plebanski tensor in a couple of areas of general relativity is also briefly discussed

Ricci curvature: An economic indicator for market fragility and systemic risk.

Science.gov (United States)

Sandhu, Romeil S; Georgiou, Tryphon T; Tannenbaum, Allen R

2016-05-01

Quantifying the systemic risk and fragility of financial systems is of vital importance in analyzing market efficiency, deciding on portfolio allocation, and containing financial contagions. At a high level, financial systems may be represented as weighted graphs that characterize the complex web of interacting agents and information flow (for example, debt, stock returns, and shareholder ownership). Such a representation often turns out to provide keen insights. We show that fragility is a system-level characteristic of "business-as-usual" market behavior and that financial crashes are invariably preceded by system-level changes in robustness. This was done by leveraging previous work, which suggests that Ricci curvature, a key geometric feature of a given network, is negatively correlated to increases in network fragility. To illustrate this insight, we examine daily returns from a set of stocks comprising the Standard and Poor's 500 (S&P 500) over a 15-year span to highlight the fact that corresponding changes in Ricci curvature constitute a financial "crash hallmark." This work lays the foundation of understanding how to design (banking) systems and policy regulations in a manner that can combat financial instabilities exposed during the 2007-2008 crisis.

AECL's participation in the commissioning of Point Lepreau generating station unit 1

International Nuclear Information System (INIS)

Chawla, S.; Singh, K.; Yerramilli, S.

1983-05-01

Support from Atomic Energy of Canada Ltd. (AECL) to Point Lepreau during the commissioning program has been in the form of: seconded staff for commissioning program management, preparation of commissioning procedures, and hands-on commissioning of several systems; analysis of test results; engineering service for problem solving and modifications; design engineering for changes and additions; procurement of urgently-needed parts and materials; technological advice; review of operational limits; interpretation of design manuals and assistance with and preparation of submissions to regulatory authorities; and development of equipment and procedures for inspection and repairs. This, together with AECL's experience in the commissioning of other 600 MWe stations, Douglas Point and Ontario Hydro stations, provides AECL with a wide range of expertise for providing operating station support services for CANDU stations

Quantisation of the holographic Ricci dark energy model

Energy Technology Data Exchange (ETDEWEB)

Albarran, Imanol; Bouhmadi-López, Mariam, E-mail: imanol@ubi.pt, E-mail: mbl@ubi.pt [Departamento de Física, Universidade da Beira Interior, 6200 Covilhã (Portugal)

2015-08-01

While general relativity is an extremely robust theory to describe the gravitational interaction in our Universe, it is expected to fail close to singularities like the cosmological ones. On the other hand, it is well known that some dark energy models might induce future singularities; this can be the case for example within the setup of the Holographic Ricci Dark Energy model (HRDE). On this work, we perform a cosmological quantisation of the HRDE model and obtain under which conditions a cosmic doomsday can be avoided within the quantum realm. We show as well that this quantum model not only avoid future singularities but also the past Big Bang.

On the K(a)hler-Ricci Flow on Projective Manifolds of General Type

Institute of Scientific and Technical Information of China (English)

Gang TIAN; Zhou ZHANG

2006-01-01

This note concerns the global existence and convergence of the solution for K(a)hler-Ricci flow equation when the canonical class, Kx, is numerically effective and big.We clarify some known results regarding this flow on projective manifolds of general type and also show some new observations and refined results.

Ricci curvature: An economic indicator for market fragility and systemic risk

Science.gov (United States)

Sandhu, Romeil S.; Georgiou, Tryphon T.; Tannenbaum, Allen R.

2016-01-01

Quantifying the systemic risk and fragility of financial systems is of vital importance in analyzing market efficiency, deciding on portfolio allocation, and containing financial contagions. At a high level, financial systems may be represented as weighted graphs that characterize the complex web of interacting agents and information flow (for example, debt, stock returns, and shareholder ownership). Such a representation often turns out to provide keen insights. We show that fragility is a system-level characteristic of “business-as-usual” market behavior and that financial crashes are invariably preceded by system-level changes in robustness. This was done by leveraging previous work, which suggests that Ricci curvature, a key geometric feature of a given network, is negatively correlated to increases in network fragility. To illustrate this insight, we examine daily returns from a set of stocks comprising the Standard and Poor’s 500 (S&P 500) over a 15-year span to highlight the fact that corresponding changes in Ricci curvature constitute a financial “crash hallmark.” This work lays the foundation of understanding how to design (banking) systems and policy regulations in a manner that can combat financial instabilities exposed during the 2007–2008 crisis. PMID:27386522

Richard Carwardine and Jay Sexton, eds., The Global Lincoln.

Directory of Open Access Journals (Sweden)

Hans Krabbendam

2012-06-01

Full Text Available Most countries have their export heroes that transcend their national origin: India has its Ghandi, South Africa its Mandela, England its Churchill, and the US has Abraham Lincoln. While particularly known for his role in the American Civil War, he has developed into an international beacon for liberalism and democracy, especially for nationals deprived of this liberties.This collection of essays, edited by Corpus Christi College (Oxford, UK colleagues Richard Carwardine and Jay Sexton, puts...

Low-level waste (LLW) reclamation program for the Point Lepreau Solid Radioactive Waste Management Facility (SRWMF)

International Nuclear Information System (INIS)

Mersereau, M.; McIntyre, K.

2006-01-01

Low level radioactive waste retrieved from intermediate storage vaults at Point Lepreau Generating Station has been sorted to remove the non-radioactive portion. The program began with trials to validate procedures and equipment, followed by a production run that is on-going. Waste boxes are opened and sorted at a ventilated sorting table. The sorted waste is directed to the station's free-release ('Likely Clean') waste stream or to the radioactive waste stream, depending on activity measurements. The radioactive waste content of the sorted materials has been reduced by 96% (by mass) using this process. (author)

Low-level waste (LLW) reclamation program for the Point Lepreau Solid Radioactive Waste Management Facility (SRWMF)

Energy Technology Data Exchange (ETDEWEB)

Mersereau, M.; McIntyre, K. [Point Lepreau Generating Station, Lepreau, New Brunswick (Canada)]. E-mail: MMersereau@nbpower.com; KMcIntyre@nbpower.com

2006-07-01

Low level radioactive waste retrieved from intermediate storage vaults at Point Lepreau Generating Station has been sorted to remove the non-radioactive portion. The program began with trials to validate procedures and equipment, followed by a production run that is on-going. Waste boxes are opened and sorted at a ventilated sorting table. The sorted waste is directed to the station's free-release ('Likely Clean') waste stream or to the radioactive waste stream, depending on activity measurements. The radioactive waste content of the sorted materials has been reduced by 96% (by mass) using this process. (author)

Likelihood and consequences of fuel string compression at Point Lepreau Generating Station

International Nuclear Information System (INIS)

Reid, P.J.; Gibb, R.A.

1996-01-01

During an accident which results in fuel heatup, axial thermal expansion of the fuel string relative to the pressure tube will occur. If the temperature transient is sufficiently severe, the fuel string may contact the shieled plugs at both ends of the channel. Any additional axial thermal expansion will result in deformation of fuel and fuel channel components, leading to tensile or compressive stresses in the different fuel channel components. If these loads become sufficiently large, they could result in failure of a fuel channel component or to channel failure due to bending of a fuel element under load. The analysis described in this paper demonstrates that this process would not result in fuel channel failure for a design basis accident at Point Lepreau Generating Station (PLGS), even if the station were retubed to 'as-built' channel lengths. (author)

Steam generators secondary side chemical cleaning at Point Lepreau using the Siemens high temperature process

International Nuclear Information System (INIS)

Verma, K.; MacNeil, C.; Odar, S.; Kuhnke, K.

1997-01-01

This paper describes the chemical cleaning of the four steam generators at the Point Lepreau facility, which was accomplished as a part of a normal service outage. The steam generators had been in service for twelve years. Sludge samples showed the main elements were Fe, P and Na, with minor amounts of Ca, Mg, Mn, Cr, Zn, Cl, Cu, Ni, Ti, Si, and Pb, 90% in the form of Magnetite, substantial phosphate, and trace amounts of silicates. The steam generators were experiencing partial blockage of broached holes in the TSPs, and corrosion on tube ODs in the form of pitting and wastage. In addition heat transfer was clearly deteriorating. More than 1000 kg of magnetite and 124 kg of salts were removed from the four steam generators

Science and the Humanities: Stephen Jay Gould's Quest to Join the High Table

Science.gov (United States)

Ruse, Michael

2013-01-01

Stephen Jay Gould was a scientist, a paleobiologist, who was also a professional-level historian of science. This essay explores Gould's work, showing how he used the history of science to further his agenda as a working scientist.

Point Lepreau refurbishment - update 5

International Nuclear Information System (INIS)

White, R.M.; Eagles, E.R.; Hickman, C.N.; Baker, R.; Thompson, P.D.; Howieson, J.Q.; Ichiyen, N.

2005-01-01

NB Power Nuclear is planning to conduct a 18-month maintenance outage of the Point Lepreau Generating Station (PLGS) beginning in April 2008. The major activity would be the replacement of all 380 Fuel Channel and Calandria Tube assemblies and connecting feeder pipes. This activity is referred to as Retube. NB Power Nuclear would also take advantage of this outage to conduct a number of repairs, replacements, inspection and upgrades (such as rewinding or replacing the generator, replacement of shutdown system trip computers, replacement of certain valves and expansion joints, inspection of systems not normally accessible, etc.). These collective activities are referred to as Refurbishment. This would allow the station to operate for an additional 25 to 30 years. The scope or the project was determined [mm the outcome of a two year study involving a detailed condition assessment of the station which examined Issues relating to ageing and obsolescence, along with a detailed review or Safety and Licensing issues associated with extended operation. The Refurbishment outage would be preceded by a detailed Engineering Project Phase that would: Finalize details of the Retube process including modeling, tooling development, site facilities and training of personnel. Perform necessary engineering activities related to design modifications. Construct the new waste storage structures to house Retube Waste and other additional waste storage structures for the extended life of the station. Setup necessary temporary construction facilities (offices, storage areas, change moms, decontamination an maintenance areas) to support Retube. Procure equipment and components. Perform detailed outage planning. Initiate development of detailed commissioning as well as lay-up, monitoring and return to service procedures. At the present time, the NB Power Nuclear Board of Directors and the New Brunswick Provincial government are reviewing a proposal for a lease arrangement from Bruce Power

Ricci-Gauss-Bonnet holographic dark energy

Science.gov (United States)

Saridakis, Emmanuel N.

2018-03-01

We present a model of holographic dark energy in which the infrared cutoff is determined by both the Ricci and the Gauss-Bonnet invariants. Such a construction has the significant advantage that the infrared cutoff, and consequently the holographic dark energy density, does not depend on the future or the past evolution of the universe, but only on its current features, and moreover it is determined by invariants, whose role is fundamental in gravitational theories. We extract analytical solutions for the behavior of the dark energy density and equation-of-state parameters as functions of the redshift. These reveal the usual thermal history of the universe, with the sequence of radiation, matter and dark energy epochs, resulting in the future to a complete dark energy domination. The corresponding dark energy equation-of-state parameter can lie in the quintessence or phantom regime, or experience the phantom-divide crossing during the cosmological evolution, and its asymptotic value can be quintessencelike, phantomlike, or be exactly equal to the cosmological-constant value. Finally, we extract the constraints on the model parameters that arise from big bang nucleosynthesis.

Aging management program of the reactor building concrete at Point Lepreau Generating Station

Science.gov (United States)

Aldea, C.-M.; Shenton, B.; Demerchant, M. M.; Gendron, T.

2011-04-01

In order for New Brunswick Power Nuclear (NBPN) to control the risks of degradation of the concrete reactor building at the Point Lepreau Generating Station (PLGS) the development of an aging management plan (AMP) was initiated. The intention of this plan was to determine the requirements for specific structural components of concrete of the reactor building that require regular inspection and maintenance to ensure the safe and reliable operation of the plant. The document is currently in draft form and presents an integrated methodology for the application of an AMP for the concrete of the reactor building. The current AMP addresses the reactor building structure and various components, such as joint sealant and liners that are integral to the structure. It does not include internal components housed within the structure. This paper provides background information regarding the document developed and the strategy developed to manage potential degradation of the concrete of the reactor building, as well as specific programs and preventive and corrective maintenance activities initiated.

Crossing the phantom divide with Ricci-like holographic dark energy

Energy Technology Data Exchange (ETDEWEB)

Lepe, S. [Pontificia Universidad Catolica de Valparaiso, Instituto de Fisica, Facultad de Ciencias, Casilla, Valparaiso (Chile); Pena, F. [Universidad de La Frontera, Departamento de Ciencias Fisicas, Facultad de Ingenieria, Ciencias y Administracion, Temuco (Chile)

2010-10-15

In this work we study the dark energy problem by adopting an holographic model proposed recently in the literature. In this model there has been postulated an energy density {rho}{proportional_to}R, where R is the Ricci scalar curvature. Under this consideration, we have obtained a cosmological scenario which arises from considering two non-interacting fluids along the lines of a reasonable Ansatz for the cosmic coincidence parameter. We have adjusted the involved parameters in the model according to the observational data, showing that the equation of state for the dark energy exhibits a cross through the -1 barrier. Additionally, we have found a disagreement of these parameters in comparison with a scalar field theory approach. (orig.)

Demonstration irradiation of CANFLEX in Pt. Lepreau

International Nuclear Information System (INIS)

Inch, W.; Thompson, P.; Suk, Ho Chun

1999-01-01

The demonstration irradiation of CANFLEX in the Point Lepreau Generating Station (PLGS) in New Brunswick, Canada, will mark a major milestone towards delivering this new fuel to CANDU utilities. One high-powered and one instrumented fuel channel are being fuelled with CANFLEX bundles to establish irradiation experience in a power reactor. As CANFLEX is discharged into the reactor bays, it win be examined by fuel experts from PLGS and AECL. Several irradiated CANFLEX bundles will be shipped to Chalk River for extensive post-irradiation examination. CANFLEX is the latest fuel carrier in the evolution of CANDU fuel. Its design has been driven to provide higher dryout powers and lower peak element ratings, while being fully compatible with existing CANDU stations and addressing the development requirements for future advanced CANDU stations. The design has been tuned through analysis and testing at AECL and KAERI. The final CANFLEX design has undergone extensive analysis, performance testing and critical industry review. Safety performance has been analyzed and documented in a licensing submission to the Canadian regulator, the Atomic Energy Control Board, for approval to proceed with the demonstration irradiation. Because CANFLEX is fully compatible with existing plants, CANDU 6 stations can simply substitute CANFLEX-NU for 37-element fuel and achieve improved reactor operating and safety margins, and higher critical channel powers. For CANDU designers, CANFLEX provides the opportunity to benefit from the use of slightly enriched uranium (SEU) or recycled uranium (RU) from reprocessed spent PWR fuel. Enrichment can be used in one of several ways: to increase the power from a given reactor core size through flattening the radial channel power profile; to increase the fuel burnup and reduce the quantity of spent fuel; to improve fuel cycle economics, both front- and back-end; and, in general, to provide greater flexibility in reactor design. (author)

Integrating Science & Management: Florida Scrub-Jay Conservation along the Central Florida's Atlantic Coast

Science.gov (United States)

Breininger, David R.

2018-01-01

Florida scrub-jays are a species listed under the Endangered Species Act. The NASA Ecology program has been a partner for conservation, recovery, and translocation across the species range. The objectives of this talk are to update members of the Archie Carr Working Group recovery, conservation, and translocation activities and describe how the Archie Carr National Wildlife Refuge and nearby conservation lands relate to species recovery actions.

Mesotocin influences pinyon jay prosociality.

Science.gov (United States)

Duque, J F; Leichner, W; Ahmann, H; Stevens, J R

2018-04-01

Many species exhibit prosocial behaviour, in which one individual's actions benefit another individual, often without an immediate benefit to itself. The neuropeptide oxytocin is an important hormonal mechanism influencing prosociality in mammals, but it is unclear whether the avian homologue mesotocin plays a similar functional role in birds. Here, we experimentally tested prosociality in pinyon jays ( Gymnorhinus cyanocephalus ), a highly social corvid species that spontaneously shares food with others. First, we measured prosocial preferences in a prosocial choice task with two different pay-off distributions: Prosocial trials delivered food to both the subject and either an empty cage or a partner bird, whereas Altruism trials delivered food only to an empty cage or a partner bird (none to subject). In a second experiment, we examined whether administering mesotocin influenced prosocial preferences. Compared to choices in a control condition, we show that subjects voluntarily delivered food rewards to partners, but only when also receiving food for themselves (Prosocial trials), and administration of high levels of mesotocin increased these behaviours. Thus, in birds, mesotocin seems to play a similar functional role in facilitating prosocial behaviours as oxytocin does in mammals, suggesting an evolutionarily conserved hormonal mechanism for prosociality. © 2018 The Author(s).

Ricci cubic gravity in d dimensions, gravitons and SAdS/Lifshitz black holes

Energy Technology Data Exchange (ETDEWEB)

Ghodsi, Ahmad; Najafi, Farzaneh [Ferdowsi University of Mashhad, Department of Physics, Mashhad (Iran, Islamic Republic of)

2017-08-15

A special class of higher curvature theories of gravity, Ricci cubic gravity (RCG), in general d dimensional space-time has been investigated in this paper. We have used two different approaches, the linearized equations of motion and the auxiliary field formalism to study the massive and massless graviton propagating modes of the AdS background. Using the auxiliary field formalism, we have found the renormalized boundary stress tensor to compute the mass of the Schwarzschild-AdS and Lifshitz black holes in RCG theory. (orig.)

Understanding the Snake Venom Metalloproteinases: An Interview with Jay Fox and José María Gutiérrez.

Science.gov (United States)

Fox, Jay W; Gutiérrez, José María

2017-01-16

Jay W. Fox and José María Gutiérrez recently finished editing a Special Issue on the topic "Snake Venom Metalloproteinases" in Toxins . The Special Issue covers a wide range of topics, including the molecular evolution and structure of snake venom metalloproteinases (SVMPs), the mechanisms involved in the generation of diversity of SVMPs, the mechanism of action of SVMPs, and their role in the pathophysiology of envenomings, with implications for improving the therapy of envenomings. In this interview, we discussed with Jay W. Fox and José María Gutiérrez their research on the SVMPs and their perspectives on the future trends and challenges for studying snake venoms.

Does niche divergence accompany allopatric divergence in Aphelocoma jays as predicted under ecological speciation? Insights from tests with niche models.

Science.gov (United States)

McCormack, John E; Zellmer, Amanda J; Knowles, L Lacey

2010-05-01

The role of ecology in the origin of species has been the subject of long-standing interest to evolutionary biologists. New sources of spatially explicit ecological data allow for large-scale tests of whether speciation is associated with niche divergence or whether closely related species tend to be similar ecologically (niche conservatism). Because of the confounding effects of spatial autocorrelation of environmental variables, we generate null expectations for niche divergence for both an ecological-niche modeling and a multivariate approach to address the question: do allopatrically distributed taxa occupy similar niches? In a classic system for the study of niche evolution--the Aphelocoma jays--we show that there is little evidence for niche divergence among Mexican Jay (A. ultramarina) lineages in the process of speciation, contrary to previous results. In contrast, Aphelocoma species that exist in partial sympatry in some regions show evidence for niche divergence. Our approach is widely applicable to the many cases of allopatric lineages in the beginning stages of speciation. These results do not support an ecological speciation model for Mexican Jay lineages because, in most cases, the allopatric environments they occupy are not significantly more divergent than expected under a null model.

Musei parlanti. Corrado Ricci e la sfida di comunicare ad un ampio pubblico / Talking museums. Corrado Ricci and the challenge of communicating the museum to a wide audience

Directory of Open Access Journals (Sweden)

Silvia Cecchini

2013-05-01

Full Text Available Nel ruolo di direttore di musei Corrado Ricci sperimenta, tra il 1893 e il 1904, la possibilità di far comunicare il museo con un pubblico più ampio degli addetti ai lavori attraverso sale allestite secondo un impianto tipologico-iconografico.  Crea così le sale storico-topografiche e le sale dei ritratti. Il modello viene realizzato per la prima volta nella Galleria Reale di Parma, poi replicato nella Galleria Estense di Modena, nell’Accademia Carrara di Bergamo, ed anche nella mostra temporanea dedicata all’antica arte senese. Introduce uno spazio di mediazione tra gli spazi della città e le sale del museo, tra il tempo presente della vita e il passato ritratto nei quadri. Proposte che oggi ci possono sollecitare a riflettere sul ruolo della ricerca e su quello della traduzione, momenti essenziali del messaggio che il museo vorrebbe trasmettere.   As Museum Director Corrado Ricci experiences, between 1893 and 1904, the ability to communicate the Museum to a wider audience then the scholars through halls outfitted with a typological-iconographic system. He creates topographic-historic rooms and rooms of portraits. The model is realized for the first time in the Royal Gallery of Parma, then replicated in Galleria Estense in Modena, in the Accademia Carrara of Bergamo, and also in the temporary exhibition dedicated to ancient art of Siena. He introduces a mediation between the spaces of the city and the rooms of the Museum, between the present life and the past of the paintings. Proposals that today we shall seek to reflect on the role of research and translation, essential moments of the message that the Museum would like to transmit.

Aging management program of the reactor building concrete at Point Lepreau Generating Station

Directory of Open Access Journals (Sweden)

Gendron T.

2011-04-01

Full Text Available In order for New Brunswick Power Nuclear (NBPN to control the risks of degradation of the concrete reactor building at the Point Lepreau Generating Station (PLGS the development of an aging management plan (AMP was initiated. The intention of this plan was to determine the requirements for specific structural components of concrete of the reactor building that require regular inspection and maintenance to ensure the safe and reliable operation of the plant. The document is currently in draft form and presents an integrated methodology for the application of an AMP for the concrete of the reactor building. The current AMP addresses the reactor building structure and various components, such as joint sealant and liners that are integral to the structure. It does not include internal components housed within the structure. This paper provides background information regarding the document developed and the strategy developed to manage potential degradation of the concrete of the reactor building, as well as specific programs and preventive and corrective maintenance activities initiated.

Using the PAW/PEM monitoring systems to support operations at Point Lepreau

International Nuclear Information System (INIS)

MacDonald, S.; McIntyre, M.; Dai, H.

1997-01-01

The plant data logger was brought on-line at the Point Lepreau Generating Station (PLGS) in 1992 in order to record information from instruments throughout the plant. Using the System Engineers Data Extraction (SEDE) utility, current plant data is at the fingertips of anyone with a network connection. System engineers can monitor the performance of their systems at any time and take pro-active measures to avoid problems with performance, as well as monitor behaviour during tests and plant upsets. Nuclear Safety personnel gather data for use in simulation and analysis validation, as well as to ensure that plant parameters are kept within the safe operating envelope. The PLGS operational safety group embarked on a project to develop a data management system. The project and the monitoring process has come to be known as the Plant Analysis Workbench (PAW). When the need for complex monitoring of safety system signals was identified, this led to a similar project called the Plant Expert Monitor (PEM). In this paper we present an overview of the functionality of both PAW and PEM, outlining in particular the expert system architecture in PEM and giving an example of its day-to-day use

Unifying dark energy and dark matter with the modified Ricci model

International Nuclear Information System (INIS)

Zhang, Linsen; Wu, Puxun; Yu, Hongwei

2011-01-01

In this paper, two modified Ricci models are considered as the candidates of unified dark matter-dark energy. In model one, the energy density is given by ρ MR =3M pl (αH 2 + βH), whereas, in model two, by ρ MR =3M pl ((α)/(6)R + γH H -1 ). We find that they can explain both dark matter and dark energy successfully. A constant equation of state of dark energy is obtained in model one, which means that it gives the same background evolution as the wCDM model, while model two can give an evolutionary equation of state of dark energy with the phantom divide line crossing in the near past. (orig.)

Holographik, the k-essential approach to interactive models with modified holographic Ricci dark energy

Energy Technology Data Exchange (ETDEWEB)

Forte, Monica [Universidad de Buenos Aires, Departamento de Fisica, Facultad de ciencias Exactas y Naturales, Buenos Aires (Argentina)

2016-12-15

We make a scalar representation of interactive models with cold dark matter and modified holographic Ricci dark energy through unified models driven by scalar fields with non-canonical kinetic term. These models are applications of the formalism of exotic k-essences generated by the global description of cosmological models with two interactive fluids in the dark sector and in these cases they correspond to the usual k-essences. The formalism is applied to the cases of constant potential in Friedmann-Robertson-Walker geometries. (orig.)

SSCI 125 emulation of Point Lepreau G.S

International Nuclear Information System (INIS)

MacLean, M.; Hogg, J.; Newman, H.; Thompson, H.

1997-01-01

A C language program has been developed at the Point Lepreau Nuclear Generating Station which emulates the actions of an SSCI 125 computer's instruction set and also emulates the actions of those input and output devices which belong to the plant control computer of the nuclear power plant's full scope training simulator. This enables the same DCC software to run on both the $20 million dollar training simulator and an equivalent desktop simulator whose hardware cost is now $16,000 or less. It facilitates making additional copies of the $20 million dollar training simulator for less than 0.1% of the cost per copy. When this emulation program is run on a 266 MHz DEC single CPU Alpha computer, it simulates the running of the training simulator plant control DCC (digital control computer) at approximately the rate of real time: either faster or slightly slower depending on the compiler options employed and depending on the choice of the modeled machine cycle speed of the SSCI. Using the standard machine cycle speed of 660 nanoseconds, using the emulator fully optimized and using plant process modelling without optimization the speed is 90% as fast as real time - this is the normal use situation for simulator modelers who were the originally intended users of the emulator. If the modeled SSCI machine cycle speed is slowed down to 792 nanoseconds (making use of space capacity on the real SSCI to reduce the workload of emulation), and all objects are compiled as optimized, then it takes only about 20 minutes of clock time to simulate over 30 minutes of modelling time. This mode of simulation may be useful for somebody who is not doing emulator or modeling code development. This could include preparing lesson plans for the training simulator, developing or evaluating plant operating procedures or trying out revised DCC software. (DM)

AECB staff annual assessment of the Point Lepreau Nuclear Generating Station for the year 1994

International Nuclear Information System (INIS)

1995-06-01

This report is the Atomic Energy Control Board assessment of safety at Point Lepreau Generating Station for 1994. AECB on-site Project Officers, and Ottawa based specialists monitored the station throughout the year. The station operated safely during 1994. Performance of the special safety systems was very good, and NB Power made important progress improving the safety management of these systems. NB Power staff failed to comply with the conditions of our Operating Licence seven times during 1994. This is an improvement from last year, but the number of compliance problems is still too high. NB Power introduced safety culture training for its staff last year. AECB is optimistic that this will help to improve compliance. The station fully met the radiation safety requirements during the year. Releases of radioactive material to the environment are well below the limits set. Radiation exposure to workers are being well controlled, and AECB believe that NB Power is maintaining these exposures 'As Low As Reasonably Achievable' for this reactor type

Improvement of Point Lepreau Generating Station ROP detector characteristics by adjusting gains in compensation amplifiers

Energy Technology Data Exchange (ETDEWEB)

Anghel, V., E-mail: vinicius.anghel@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Basque, M.-J. [Atlantic Nuclear Services Inc., Fredericton, New Brunswick (Canada); Comeau, D. [Point Lepreau Generating Station, Lepreau, New Brunswick (Canada); Sur, B. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Taylor, D. [Point Lepreau Generating Station, Lepreau, New Brunswick (Canada)

2015-06-15

Canadian Pressurized Heavy Water Reactors are protected against reactor overpower by 2 independent shutdown systems: Shut Down System 1 and 2. At Point Lepreau Generating Station, these shutdown systems can be actuated by signals from Platinum-clad Inconel In-Core Flux Detectors measuring the neutron flux. These detectors have a complex dynamic behaviour, characterized by 'prompt' and 'delayed' components with respect to immediate changes in the in-core neutron flux. In aging detectors, it was found that the prompt response decreases. A detector response that actuates the shutdown system effectively has to have a large prompt response and a small delayed response. These required responses may be obtained by adjusting the dynamic compensation amplifiers (compensator) settings. This paper presents the measured results of a compensation adjustment procedure for the in-core platinum-clad Inconel detectors. The compensation is computed from the detector parameters estimated by VS, a fully automated and qualified computer program that analyzes the response of the detectors. (author)

Alternative methodology for assessing part-through-wall cracks in carbon steel bends removed from Point Lepreau Generating Station

Energy Technology Data Exchange (ETDEWEB)

Duan Xinjian, E-mail: duanx@aecl.c [Senior Engineer, Reactor Engineering Department, Atomic Energy of Canada Ltd., Mississauga, ON (Canada); Kozluk, Michael J., E-mail: kozlukm@aecl.c [Independent Consultant, Oakville, ON (Canada); Gendron, Tracy [Manager-HTS Materials Integrity, Atomic Energy of Canada Ltd., Chalk River, ON (Canada); Slade, John [Senior Technical Advisor, Point Lepreau Generating Station, Lepreau, NB (Canada)

2011-03-15

In 2008 April Point Lepreau Generating Station entered an extended refurbishment outage that will involve the replacement of key reactor components (fuel channels and connecting feeder pipes). Prior to the refurbishment outage, New Brunswick Power Nuclear had been successfully managing intergranular, axial cracking of carbon steel feeder piping, that were also experiencing thinning, in the Point Lepreau Generating Station, primarily by an aggressive program of inspection, repair and testing of ex-service material. For the previous three maintenance outages, a probabilistic safety evaluation (PSE) had been used to demonstrate that annual inspection of the highest risk locations maintains the nuclear safety risk from cracking at an acceptably low level. The PSE makes use of the Failure Assessment Diagram (FAD) model to predict the failure of part-through-wall cracks. Burst-pressure testing of two ex-service feeder pipe sections with part-through-wall cracks showed that this FAD model significantly under predicts the failure pressure measured in the component tests. Use of this FAD model introduces undesirable conservatism into PSE assessments that are used to optimize feeder piping inspection and maintenance plans. This paper describes an alternative finite element approach, which could be used to provide more representative structural models for use in PSE assessments. This alternative approach employs the elasto-plastic large strain finite element formulation; uses representative material properties; considers the spatial microstructural distribution; accounts for the effect of work hardening rate; models all deformation processes, i.e., uniform deformation, localized necking, and failure imitation and propagation. Excellent pre-test prediction was shown for the burst-pressure test performed in 2006. Although cold-worked feeder bends have reduced fracture toughness compared to the parent straight pipe, post-test metallurgical examinations showed that failure at the

Desire-state attribution: Benefits of a novel paradigm using the food-sharing behavior of Eurasian jays (Garrulus glandarius).

Science.gov (United States)

Ostojić, Ljerka; Cheke, Lucy G; Shaw, Rachael C; Legg, Edward W; Clayton, Nicola S

2016-01-01

In recent years, we have investigated the possibility that Eurasian jay food sharing might rely on desire-state attribution. The female's desire for a particular type of food can be decreased by sating her on it (specific satiety) and the food sharing paradigm can be used to test whether the male's sharing pattern reflects the female's current desire. Our previous findings show that the male shares the food that the female currently wants. Here, we consider 3 simpler mechanisms that might explain the male's behavior: behavior reading, lack of self-other differentiation and behavioral rules. We illustrate how we have already addressed these issues and how our food sharing paradigm can be further adapted to answer outstanding questions. The flexibility with which the food sharing paradigm can be applied to rule out alternative mechanisms makes it a useful tool to study desire-state attribution in jays and other species that share food.

Effective Integration of Technology and Instruction. Q&A with Michael Jay. REL Mid-Atlantic Educator Effectiveness Webinar Series

Science.gov (United States)

Regional Educational Laboratory Mid-Atlantic, 2015

2015-01-01

In this webinar, long-time educator and developer of education technology Michael Jay discussed the importance of using technology to support learning and gave examples of how teachers can integrate technology into their instruction based on the Common Core State Standards and the Next Generation Science Standards. The PowerPoint presentation and…

Science, Intelligence, and Educational Policy: The Mismeasure of Frankenstein (with Apologies to Mary Shelley and Stephen Jay Gould).

Science.gov (United States)

Zappardino, Pamela

Stephen Jay Gould points out in "The Mismeasure of Man" (1981), "Science, since people must do it, is a socially embedded activity. It progresses by hunch, vision, and intuition." The legacy of the traditional construct of intelligence and its measurement through intelligence quotient (IQ) tests has not been educational improvement. Its legacy in…

Modified holographic Ricci dark energy coupled to interacting dark matter and a non-interacting baryonic component

Energy Technology Data Exchange (ETDEWEB)

Chimento, Luis P.; Richarte, Martin G. [Universidad de Buenos Aires, IFIBA, CONICET, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Forte, Monica [Universidad de Buenos Aires, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)

2013-01-15

We examine a Friedmann-Robertson-Walker universe filled with interacting dark matter, modified holographic Ricci dark energy (MHRDE), and a decoupled baryonic component. The estimations of the cosmic parameters with Hubble data lead to an age of the universe of 13.17 Gyr and show that the MHRDE is free from the cosmic-age problem at low redshift (0{<=}z{<=}2) in contrast to holographic Ricci dark energy (HRDE) case. We constrain the parameters with the Union2 data set and contrast with the Hubble data. We also study the behavior of dark energy at early times by taking into account the severe bounds found at recombination era and/or at big bang nucleosynthesis. The inclusion of a non-interacting baryonic matter forces that the amount of dark energy at z{sub t} {proportional_to} O(1) changes abruptly implying that {Omega} {sub x} (z {approx_equal}1100)=0.03, so the bounds reported by the forecast of Planck and CMBPol experiments are more favored for the MHRDE model than in the case of HRDE cutoff. For the former model, we also find that at high redshift the fraction of dark energy varies from 0.006 to 0.002, then the amount of {Omega} {sub x} at the big bang nucleosynthesis era does not disturb the observed helium abundance in the universe provided that the bound {Omega} {sub x} (z {approx_equal}10 {sup 10}) <0.21 is hold. (orig.)

Conformal invariant powers of the Laplacian, Fefferman-Graham ambient metric and Ricci gauging

International Nuclear Information System (INIS)

Manvelyan, Ruben; Mkrtchyan, Karapet; Mkrtchyan, Ruben

2007-01-01

The hierarchy of conformally invariant kth powers of the Laplacian acting on a scalar field with scaling dimensions Δ (k) =k-d/2, k=1,2,3, as obtained in the recent work [R. Manvelyan, D.H. Tchrakian, Phys. Lett. B 644 (2007) 370, (hep-th/0611077)] is rederived using the Fefferman-Graham (d+2)-dimensional ambient space approach. The corresponding mysterious 'holographic' structure of these operators is clarified. We explore also the (d+2)-dimensional ambient space origin of the Ricci gauging procedure proposed by A. Iorio, L. O'Raifeartaigh, I. Sachs and C. Wiesendanger as another method of constructing the Weyl invariant Lagrangians. The corresponding gauged ambient metric, Fefferman-Graham expansion and extended Penrose-Brown-Henneaux transformations are proposed and analyzed

Partner Symmetries, Group Foliation and ASD Ricci-Flat Metrics without Killing Vectors

Directory of Open Access Journals (Sweden)

Andrei A. Malykh

2013-11-01

Full Text Available We demonstrate how a combination of our recently developed methods of partner symmetries, symmetry reduction in group parameters and a new version of the group foliation method can produce noninvariant solutions of complex Monge-Ampère equation (CMA and provide a lift from invariant solutions of CMA satisfying Boyer-Finley equation to non-invariant ones. Applying these methods, we obtain a new noninvariant solution of CMA and the corresponding Ricci-flat anti-self-dual Einstein-Kähler metric with Euclidean signature without Killing vectors, together with Riemannian curvature two-forms. There are no singularities of the metric and curvature in a bounded domain if we avoid very special choices of arbitrary functions of a single variable in our solution. This metric does not describe gravitational instantons because the curvature is not concentrated in a bounded domain.

Point Lepreau refurbishment project programmable digital comparator (PDC) replacement for SDS1 and SDS2

International Nuclear Information System (INIS)

Ichiyen, N.M.; Chan, D.; Thompson, P.D.

2003-01-01

NB Power is tentatively planning to conduct an 18-month maintenance outage of the Point Lepreau Generating Station (PLGS) starting in April 2007. The scope of the outage was determined from the outcome of a two year study (Phase 1) involving a detailed condition assessment of the station which examined issues relating to ageing and obsolescence, along with a detailed review of Safety and Licensing issues associated with extended operation. In order to minimize schedule and regulatory risk for the Refurbishment project, pre-project work was initiated in early 2002. This program is called Phase 2 ESA (Early Start Activities). As part of the Phase 1 assessments it was concluded that replacement of the PDCs (Programmable Digital Comparators) for both shutdown systems was required in order to ensure operation of the plant for a further 25-30 years. Critical tasks were identified related to PDC replacement as part of the Phase 2 ESA program. This paper describes the activities that have taken place in the Phase 2 ESA program as well as the plan for future work for the PDC replacement for SDS 1 (Shutdown System Number One) and SDS2 (Shutdown System Number Two). (author)

Point Lepreau Refurbishment Project. Programmable digital comparator (PDC) replacement for SDS1 and SDS2 - update 1

International Nuclear Information System (INIS)

Fraser, K.G.; Ichiyen, N.M.; Condor, A.E.; Thompson, P.D.

2005-01-01

NB Power is tentatively planning to conduct an 18-month maintenance outage of the Point Lepreau Generating Station starting in April 2008. The scope of the outage was determined from the outcome of a two year study (Phase 1) involving a detailed condition assessment of the station which examined issues relating to ageing and obsolescence, along with a detailed review of Safety and Licensing issues associated with extended operation. In order to minimize schedule and regulatory risk for the Refurbishment project, pre-project work was initiated in early 2002. This program is called Phase 2 ESA (Early Start Activities). As part of the Phase 1 assessments it was concluded that replacement of the Programmable Digital Comparators for both shutdown systems was required in order to ensure operation of the plant for a further 25-30 years. Critical tasks were identified related to PDC replacement as part of the Phase 2 ESA program. This paper describes the progress of the Phase 2 ESA program as well as the planned future (Phase 2) work for the PDC replacement for both shutdown systems. (author)

Telling It Like It Is--And Like It Is Not: Fiction in the Service of Science in Jay Hosler's "The Sandwalk Adventures"

Science.gov (United States)

Porat, Michal

2015-01-01

Biologist and graphic novelist Jay Hosler has long been introducing young readers to biological subjects through entertaining narratives combining strongly fictional elements with nonfictional ones. Extensive application of fiction to nonfictional subject matter is uncommon, even in graphic novels, but Hosler's "The Sandwalk Adventures"…

Evaluation of slow shutdown system flux detectors in Point Lepreau Generating Station - I: dynamic response characterization

Energy Technology Data Exchange (ETDEWEB)

Anghel, V.N.P. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Comeau, D. [New Brunswick Power Nuclear, Point Lepreau, New Brunswick (Canada); McKay, J.; Sur, B. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Taylor, D. [New Brunswick Power Nuclear, Point Lepreau, New Brunswick (Canada)

2009-07-01

CANDU reactors are protected against reactor overpower by two independent shutdown systems: Shut Down System 1 and 2 (SDS1 and SDS2). At the Point Lepreau Generating Station (PLGS), the shutdown systems can be actuated by measurements of the neutron flux by Platinum-clad Inconel In-Core Flux Detectors (ICFDs). These detectors have a complex dynamic behaviour, characterized by 'prompt' and 'delayed' components with respect to immediate changes in the in-core neutron flux. The dynamic response components need to be determined accurately in order to evaluate the effectiveness of the detectors for actuating the shutdown systems. The amplitudes of the prompt and the delayed components of individual detectors were estimated over a period of several years by comparison of archived detector response data with the computed local neutron flux evolution for SDS1 and SDS2 reactor trips. This was achieved by custom-designed algorithms. The results of this analysis show that the dynamic response of the detectors changes with irradiation, with the SDS2 detectors having 'prompt' signal components that decreased significantly with irradiation. Some general conclusions about detector aging effects are also drawn. (author)

Co-ordination of federal and provincial environmental assessment processes for the Point Lepreau Generating Station Solid Radioactive Waste Management Facility modifications

International Nuclear Information System (INIS)

Hickman, C.; Thompson, P.D.; Barnes, J.

2006-01-01

Modification of the Solid Radioactive Waste Management Facility at Point Lepreau Generating Station is required to accommodate waste generated during and after an 18-month maintenance outage during which the station would be Refurbished. The modification of the facility triggered both federal and provincial environmental assessment requirements, and these assessments were conducted in a 'coordinated' and cooperative fashion. In this project, the coordinated approach worked well, and provided some significant advantages to the proponent, the public and the regulators. However, there are opportunities for further improvement in future projects, and this paper explores the advantages and disadvantages of this 'co-ordinated' approach. As part of this exploration, there is a discussion of administrative and regulatory changes that the province is considering for the environmental assessment process, and a discussion of the need for a formal 'harmonization' agreement. (author)

S08: investigation and repair of a cracked feeder at Point Lepreau GS

International Nuclear Information System (INIS)

A Celovsky, A.; Wright, M.D.; Gendron, T.S.

1997-01-01

Early in 1997 investigation of a low level leak in the Point Lepreau GS (PLGS) PHTS revealed that an outlet feeder, S08, was leaking. Ultrasonic inspection, and subsequent failure analysis, revealed that the leak was a consequence of a crack. Given the unusual nature of this event, and current concerns over feeder thinning, a detailed and careful removal and examination procedure was developed. The S08 outlet feeder was removed and shipped to Chalk River Laboratories for examination. The examination confirmed that the failure was a through-wall crack, most likely the consequence of stress corrosion cracking. A critical point of the analysis was to determine how the crack initiated, and subsequently propagated. High residual stresses and possible abnormal loading in conjunction with chemistry environments resulted in the Stress Corrosion Cracking (SCC) of the S08 outlet feeder bend. It is recognized that some of the causative factors implicated in the S08 failure apply to other outlet feeders. In particular, residual stresses in the non-stress-relieved, short-radius cold bent pipes will remain relatively high over the future life of the feeders. However, the risk of CANDU feeder failure by SCC is judged to be extremely low based on the evidence of the inspections carried out to date and the good performance record of feeder pipe in the CANDU industry. The channel was restored to its locked configuration, and the failed section of feeder replaced. (author)

Sebastiano Ricci impresario in angustie a Venezia: i guai della stagione 1718-1719 al Sant’Angelo

Directory of Open Access Journals (Sweden)

Gianluca Stefani

2016-06-01

Full Text Available Sebastiano Ricci was not only one of the greatest painters of the 18th century, but an active impresario in the Venetian opera houses at the beginning of the early 18th century. Thanks to the rediscovery of some notarial and judicial documents in the Archivio di Stato of Venice, we can reconstruct the circumstances under which he became manager of the Teatro di Sant’Angelo in the season 1718-1719, a season marked by his succession to the previous impresario Antonio Moretti (known as Modotto and by his legal dispute with the violinists Giovan Battista and Ludovico Madonis at the tribunal ‘del Forestier’.

Modified Holographic Ricci Dark Energy in Chameleon Brans–Dicke Cosmology and Its Thermodynamic Consequence

International Nuclear Information System (INIS)

Jawad, A.; Chattopadhyay, S.; Bhattacharya, S.; Pasqua, A.

2015-01-01

The objective of this paper is to discuss the Chameleon Brans–Dicke gravity with non-minimally matter coupling of scalar field. We take modified Holographic Ricci dark energy model in this gravity with its energy density in interaction with energy density of cold dark matter. We assume power-law ansatz for scale factor and scalar field to discuss potential as well as coupling functions in the evolving universe. These reconstructed functions are plotted versus scalar field and time for different values of power component of scale factor n. We observe that potential and coupling functions represent increasing behavior, in particular, consistent results for a specific value of n. Finally, we have examined validity of the generalized second law of thermodynamics and we have observed its validity for all values of n. (paper)

Monitoring and managing component fatigue at Point Lepreau Generating Station

International Nuclear Information System (INIS)

Stevens, G.L.; Yetisir, M.; Scovil, A.; Slade, J.

2008-01-01

Many CANDU plants are now approaching the end of their design lives and are being considered for extended operation beyond their design life. The Canadian Nuclear Safety Commission (CNSC) has asked utilities to address component fatigue issues in plant life extension (PLEX) applications. In particular, environmental effects on fatigue was identified as an issue that needs to be addressed, similar to being addressed for license renewal for U.S. nuclear power plants. To address CNSC concerns, the CANDU Owners Group (COG) has initiated a program to help utilities develop component fatigue management programs for PLEX operation. A summary of a pilot study that was conducted at the Point Lepreau Generating Station (PLGS) is provided below: A plant-specific Recommendation Study provided a comprehensive review of the existing plant-specific systems, cycle counting procedures, and other fatigue-related requirements, and made some general recommendations on how best to implement a fatigue management system for PLEX. The plant-specific study determined that only 10 to 15% of the design transients have been used after 25 effective full power years (EFPY) of operation. Hence, a significant amount of original design margin for fatigue usage margin remains available for PLEX operation. Environmental fatigue considerations in heavy water (D 2 O) were included in the plant-specific assessment. Only warm-up transients were assessed to have dissolved oxygen concentrations that can result in a significant environmental effect for the ferritic steels used in the CANDU primary systems. Due to the low accumulation of transients and the absence of known thermal stratification mechanisms, thermal fatigue is not as significant an issue in CANDU plants as in pressurized water reactor (PWR) and boiling water reactor (BWR) plants. The needs for implementing a comprehensive Fatigue Management Program for PLGS to satisfy PLEX requirements were defined, and specific direction and strategy for

Co-ordination of federal and provincial environmental assessment processes for the Point Lepreau Generating Station Solid Radioactive Waste Management Facility modifications

Energy Technology Data Exchange (ETDEWEB)

Hickman, C.; Thompson, P.D. [Point Lepreau Generating Station, Point Lepreau Refurbishment Project, Lepreau, New Brunswick (Canada); Barnes, J. [Jacques Whitford Environment Ltd., Fredericton, New Brunswick (Canada)

2006-07-01

Modification of the Solid Radioactive Waste Management Facility at Point Lepreau Generating Station is required to accommodate waste generated during and after an 18-month maintenance outage during which the station would be Refurbished. The modification of the facility triggered both federal and provincial environmental assessment requirements, and these assessments were conducted in a 'coordinated' and cooperative fashion. In this project, the coordinated approach worked well, and provided some significant advantages to the proponent, the public and the regulators. However, there are opportunities for further improvement in future projects, and this paper explores the advantages and disadvantages of this 'co-ordinated' approach. As part of this exploration, there is a discussion of administrative and regulatory changes that the province is considering for the environmental assessment process, and a discussion of the need for a formal 'harmonization' agreement. (author)

Evaluation of slow shutdown system flux detectors in Point Lepreau Generating Station - II: dynamic compensation error analysis

Energy Technology Data Exchange (ETDEWEB)

Anghel, V.N.P.; Sur, B. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Taylor, D. [New Brunswick Power Nuclear, Point Lepreau, New Brunswick (Canada)

2009-07-01

CANDU reactors are protected against reactor overpower by two independent shutdown systems: Shut Down System 1 and 2 (SDS1 and SDS2). At the Point Lepreau Generating Station (PLGS), the shutdown systems can be actuated by measurements of the neutron flux from Platinum-clad Inconel In-Core Flux Detectors. These detectors have a complex dynamic behaviour, characterized by 'prompt' and 'delayed' components with respect to immediate changes in the in-core neutron flux. It was shown previously (I: Dynamic Response Characterization by Anghel et al., this conference) that the dynamic responses of the detectors changed with irradiation, with the SDS2 detectors having 'prompt' signal components that decreased significantly. In this paper we assess the implication of these changes for detector dynamic compensation errors by comparing the compensated detector response with the power-to-fuel and the power-to-coolant responses to neutron flux ramps as assumed by previous error analyses. The dynamic compensation error is estimated at any given trip time for all possible accident flux ramps. Some implications for the shutdown system trip set points, obtained from preliminary results, are discussed. (author)

Investigation into anomalous lead-cable responses in vanadium sir detectors in Pt. Lepreau and Gentilly-2

International Nuclear Information System (INIS)

Sur, B.; McAllindon, D.P.; Bailey, C.M.

1997-01-01

Vanadium In-Core Flux Detectors (ICFDs) are used for flux mapping in CANDU 6 stations. The Inconel lead-cables (LCs) of these detectors produce a small (0.5% - 2%) but significant signal contribution which varies with the in-core length of the lead-cable. The ICFD signal must therefore be corrected for the lead-cable contribution to avoid biasing the flux map. Corrections for lead-cable contributions are made on the basis of a prediction of lead-cable relative sensitivity and its change with irradiation history due to the complex burn-up on the Inconel constituents. Lead-cables without any detectors are installed at the stations and monitored regularly to validate the lead-cable relative sensitivity prediction. A survey of the detector-less lead-cables at Pt. Lepreau and Gentilly-2 shows an unpredicted rapid increase and subsequent decrease in lead-cable relative sensitivity in the first few hundred full-power days after installation. In this paper, the prediction of lead-cable sensitivity and its change due to burn-up effects are reviewed. The data from the stations is presented and modeled. Possible physical causes of the rapid variation in sensitivity are explored. Further work to resolve the issue of anomalous lead-cable sensitivity is discussed. (author)

Refurbishment of Point Lepreau Generating Station

International Nuclear Information System (INIS)

Thompson, P.D.; Jaitly, R.; Ichiyen, N.; Petrilli, M.A.

2004-01-01

NB Power is planning to conduct an 18-month maintenance outage of the Point Lepreau Generating Station (PLGS) beginning in April 2008. The major activity would be the replacement of all 380 Fuel Channel and Calandria Tube Assemblies and the connecting feeder pipes. This activity is referred to as Retube. NB Power would also take advantage of this outage to conduct a number of repairs, replacements, inspections and upgrades (such as rewinding or replacing the generator, replacement of shutdown system trip computers, replacement of certain valves and expansion joints, inspection of systems not normally accessible, etc). These collective activities are referred to as Refurbishment. This would allow the station to operate for an additional 25 to 30 years. The scope of the project was determined from the outcome of a two-year study involving a detailed condition assessment of the station that examined issues relating to ageing and obsolescence. The majority of the plant components were found to be capable of supporting extended operation without needing replacement or changes. In addition to the condition assessment, a detailed review of Safety and Licensing issues associated with extended operation was performed. This included a review of known regulatory and safety issues, comparison of the station against current codes and standards, and comparison of the station against safety related modifications made to more recent CANDU 6 units. Benefit cost analyses (BCA) were performed to assist the utility in determining which changes were appropriate to include in the project scope. As a Probabilistic Safety Assessment (PSA) for PLGS did not exist at the time, a risk baseline for the station had to be determined for use in the BCA. Extensive dialogue with the Canadian Nuclear Safety Commission staff was also undertaken during this phase. A comprehensive Licensing Framework was produced upon which the CNSC provided feedback to NB Power. This feedback was important in terms of

Evaluation of options for life cycle management of feeder cracking at the Point Lepreau Generating Station

International Nuclear Information System (INIS)

Gendron, T.S.; Slade, J.P.

2003-01-01

The CANDU industry has a predictive capability for most Heat Transport System (HTS) degradation issues that allows utilities to apply cost-effective maintenance programs. The standard approach for maintenance programs is focussed inspection and planned replacement. Some examples of degradation issues with deterministic failure rates are feeder thinning, and pressure tube elongation and deuterium ingress. However, the cracking observed in Point Lepreau Generating Station (PLGS) outlet feeder first bends is one notable exception to this behaviour. A predictive capability for feeder cracking does not currently exist for several reasons. First, the mechanism of feeder cracking, stress corrosion cracking (SCC), has to some degree a random nature. Second, although a probable environment causing cracking has been identified, the precise stress and environmental conditions for feeder crack initiation and propagation have not been defined. Finally, the very low incidence of feeder cracking observed to-date (four, all at PLGS) precludes a probabilistic or statistical prediction of failure rate. Generally, utilities select a Life Cycle Management Plan that ensures safe operation and has the lowest Net Present Value cost. In preparing a Feeder Life Cycle Management Plan, New Brunswick Power (NBP) has recognized that the Net Present Value cost is very sensitive to failure rate. Since the failure rate for feeder cracking is not well defined, the following three scenarios were considered to bound the probability of future failures at PLGS. (author)

Modified Holographic Ricci Dark Energy in Chameleon Brans-Dicke Cosmology and Its Thermodynamic Consequence

Science.gov (United States)

Jawad, A.; Chattopadhyay, S.; Bhattacharya, S.; Pasqua, A.

2015-04-01

The objective of this paper is to discuss the Chameleon Brans-Dicke gravity with non-minimally matter coupling of scalar field. We take modified Holographic Ricci dark energy model in this gravity with its energy density in interaction with energy density of cold dark matter. We assume power-law ansatz for scale factor and scalar field to discuss potential as well as coupling functions in the evolving universe. These reconstructed functions are plotted versus scalar field and time for different values of power component of scale factor n. We observe that potential and coupling functions represent increasing behavior, in particular, consistent results for a specific value of n. Finally, we have examined validity of the generalized second law of thermodynamics and we have observed its validity for all values of n. The financial Supported from Department of Science and Technology, Govt. of India under Project Grant No. SR/FTP/PS-167/2011 is thankfully acknowledged by SC

DGP cosmological model with generalized Ricci dark energy

Energy Technology Data Exchange (ETDEWEB)

Aguilera, Yeremy [Universidad de Santiago, Departamento de Matematicas y Ciencia de la Computacion, Santiago (Chile); Avelino, Arturo [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Cruz, Norman [Universidad de Santiago, Departamento de Fisica, Facultad de Ciencia, Santiago (Chile); Lepe, Samuel [Pontificia Universidad Catolica de Valparaiso, Facultad de Ciencias, Instituto de Fisica, Valparaiso (Chile); Pena, Francisco [Universidad de La Frontera, Departamento de Ciencias Fisicas, Facultad de Ingenieria y Ciencias, Temuco (Chile)

2014-11-15

The brane-world model proposed by Dvali, Gabadadze and Porrati (DGP) leads to an accelerated universe without cosmological constant or other form of dark energy for the positive branch (element of = +1). For the negative branch (element of = -1) we have investigated the behavior of a model with an holographic Ricci-like dark energy and dark matter, where the IR cutoff takes the form αH{sup 2} + βH, H being the Hubble parameter and α, β positive constants of the model. We perform an analytical study of the model in the late-time dark energy dominated epoch, where we obtain a solution for r{sub c}H(z), where r{sub c} is the leakage scale of gravity into the bulk, and conditions for the negative branch on the holographic parameters α and β, in order to hold the conditions of weak energy and accelerated universe. On the other hand, we compare the model versus the late-time cosmological data using the latest type Ia supernova sample of the Joint Light-curve Analysis (JLA), in order to constrain the holographic parameters in the negative branch, as well as r{sub c}H{sub 0} in the positive branch, where H{sub 0} is the Hubble constant. We find that the model has a good fit to the data and that the most likely values for (r{sub c}H{sub 0}, α, β) lie in the permitted region found from an analytical solution in a dark energy dominated universe. We give a justification to use a holographic cutoff in 4D for the dark energy in the 5-dimensional DGP model. Finally, using the Bayesian Information Criterion we find that this model is disfavored compared with the flat ΛCDM model. (orig.)

Emergent Criticality and Ricci Flow in a 2D Frustrated Heisenberg Model

Science.gov (United States)

Orth, Peter P.

2014-03-01

In most systems that exhibit order at low temperatures, the order occurs in the elementary degrees of freedom such as spin or charge. Prominent examples are magnetic or superconducting states of matter. In contrast, emergent order describes the phenomenon where composite objects exhibit longer range correlations. Such emergent order has been suspected to occur in a range of correlated materials. One specific example are spin systems with competing interactions, where long-range discrete order in the relative orientation of spins may occur. Interestingly, this order parameter may induce other phase transitions as is the case for the nematic transition in the iron pnictides. In this talk, we introduce and discuss a system with emergent Z6 symmetry, a two-dimensional frustrated Heisenberg antiferromagnet on the windmill lattice consisting of interpenetrating honeycomb and triangular lattices. The multiple spin stiffnesses can be captured in terms of a four-dimensional metric tensor, and the renormalization group flow of the stiffnesses is described by the Ricci flow of the metric tensor. The key result is a decoupling of an emergent collective degree of freedom given by the relative phase of spins on different sublattices. In particular, our results reveal a sequence of two Berezinskii-Kosterlitz-Thouless phase transitions that bracket a critical phase.

Power Law and Logarithmic Ricci Dark Energy Models in Hořava-Lifshitz Cosmology

Science.gov (United States)

Pasqua, Antonio; Chattopadhyay, Surajit; Khurshudyan, Martiros; Myrzakulov, Ratbay; Hakobyan, Margarit; Movsisyan, Artashes

2015-03-01

In this work, we studied the Power Law and the Logarithmic Entropy Corrected versions of the Ricci Dark Energy (RDE) model in a spatially non-flat universe and in the framework of Hořava-Lifshitz cosmology. For the two cases containing non-interacting and interacting RDE and Dark Matter (DM), we obtained the exact differential equation that determines the evolutionary form of the RDE energy density. Moreover, we obtained the expressions of the deceleration parameter q and, using a parametrization of the equation of state (EoS) parameter ω D given by the relation ω D ( z) = ω 0+ ω 1 z, we derived the expressions of both ω 0 and ω 1. We interestingly found that the expression of ω 0 is the same for both non-interacting and interacting case. The expression of ω 1 for the interacting case has strong dependence from the interacting parameter b 2. The parameters derived in this work are done in small redshift approximation and for low redshift expansion of the EoS parameter.

Claiming Darwin: Stephen Jay Gould in contests over evolutionary orthodoxy and public perception, 1977-2002.

Science.gov (United States)

Sheldon, Myrna Perez

2014-03-01

This article analyzes the impact of the resurgence of American creationism in the early 1980s on debates within post-synthesis evolutionary biology. During this period, many evolutionists criticized Harvard biologist Stephen Jay Gould for publicizing his revisions to traditional Darwinian theory and opening evolution to criticism by creationists. Gould's theory of punctuated equilibrium was a significant source of contention in these disputes. Both he and his critics, including Richard Dawkins, claimed to be carrying the mantle of Darwinian evolution. By the end of the 1990s, the debate over which evolutionary thinkers were the rightful heirs to Darwin's evolutionary theory was also a conversation over whether Darwinism could be defended against creationists in the broader cultural context. Gould and others' claims to Darwin shaped the contours of a political, religious and scientific controversy. Copyright © 2014. Published by Elsevier Ltd.

Statefinder hierarchy exploration of the extended Ricci dark energy

Energy Technology Data Exchange (ETDEWEB)

Yu, Fei [Shenyang Aerospace University, College of Sciences, Shenyang (China); Cui, Jing-Lei; Zhang, Jing-Fei [Northeastern University, Department of Physics, College of Sciences, Shenyang (China); Zhang, Xin [Northeastern University, Department of Physics, College of Sciences, Shenyang (China); Peking University, Center for High Energy Physics, Beijing (China)

2015-06-15

We apply the statefinder hierarchy plus the fractional growth parameter to explore the extended Ricci dark energy (ERDE) model, in which there are two independent coefficients α and β. By adjusting them, we plot evolution trajectories of some typical parameters, including the Hubble expansion rate E, deceleration parameter q, the third and fourth-order hierarchy S{sub 3}{sup (1)} and S{sub 4}{sup (1)}, and the fractional growth parameter ε, respectively, as well as several combinations of them. For the case of variable α and constant β, in the low-redshift region the evolution trajectories of E are in high degeneracy and that of q separate somewhat. However, the ΛCDM model is confounded with ERDE in both of these cases. S{sub 3}{sup (1)} and S{sub 4}{sup (1)}, especially the former, perform much better. They can differentiate well only varieties of cases within ERDE except ΛCDM in the low-redshift region. For the high-redshift region, combinations {S_n"("1"), ε} can break the degeneracy. Both of {S_3"("1"), ε} and {S_4"("1"), ε} have the ability to discriminate ERDE with α = 1 from ΛCDM, of which the degeneracy cannot be broken by all the before-mentioned parameters. For the case of variable β and constant α, S{sub 3}{sup (1)}(z) and S{sub 4}{sup (1)}(z) can only discriminate ERDE from ΛCDM. Nothing but pairs {S_3"("1"), ε} and {S_4"("1"), ε} can discriminate not only within ERDE but also ERDE from ΛCDM. Finally, we find that S{sub 3}{sup (1)} is surprisingly a better choice to discriminate within ERDE itself, and ERDE from ΛCDM as well, rather than S{sub 4}{sup (1)}. (orig.)

Before hierarchy: the rise and fall of Stephen Jay Gould's first macroevolutionary synthesis.

Science.gov (United States)

Dresow, Max W

2017-06-01

Few of Stephen Jay Gould's accomplishments in evolutionary biology have received more attention than his hierarchical theory of evolution, which postulates a causal discontinuity between micro- and macroevolutionary events. But Gould's hierarchical theory was his second attempt to supply a theoretical framework for macroevolutionary studies-and one he did not inaugurate until the mid-1970s. In this paper, I examine Gould's first attempt: a proposed fusion of theoretical morphology, multivariate biometry and the experimental study of adaptation in fossils. This early "macroevolutionary synthesis" was predicated on the notion that parallelism and convergence dominate the history of higher taxa, and moreover, that they can be explained in terms of adaptation leading to mechanical improvement. In this paper, I explore the origins and contents of Gould's first macroevolutionary synthesis, as well as the reasons for its downfall. In addition, I consider how various developments during the mid-1970s led Gould to identify hierarchy and constraint as the leading themes of macroevolutionary studies-and adaptation as a macroevolutionary red herring.

Kaluza-Klein Multidimensional Models with Ricci-Flat Internal Spaces: The Absence of the KK Particles

Directory of Open Access Journals (Sweden)

Alexey Chopovsky

2013-01-01

Full Text Available We consider a multidimensional Kaluza-Klein (KK model with a Ricci-flat internal space, for example, a Calabi-Yau manifold. We perturb this background metrics by a system of gravitating masses, for example, astrophysical objects such as our Sun. We suppose that these masses are pressureless in the external space but they have relativistic pressure in the internal space. We show that metric perturbations do not depend on coordinates of the internal space and gravitating masses should be uniformly smeared over the internal space. This means, first, that KK modes corresponding to the metric fluctuations are absent and, second, particles should be only in the ground quantum state with respect to the internal space. In our opinion, these results look very unnatural. According to statistical physics, any nonzero temperature should result in fluctuations, that is, in KK modes. We also get formulae for the metric correction terms which enable us to calculate the gravitational tests: the deflection of light, the time-delay of the radar echoes, and the perihelion advance.

Holographic Ricci dark energy in Randall-Sundrum braneworld: Avoidance of big rip and steady state future

International Nuclear Information System (INIS)

Feng Chaojun; Zhang Xin

2009-01-01

In the holographic Ricci dark energy (RDE) model, the parameter α plays an important role in determining the evolutionary behavior of the dark energy. When α<1/2, the RDE will exhibit a quintom feature, i.e., the equation of state of dark energy will evolve across the cosmological constant boundary w=-1. Observations show that the parameter α is indeed smaller than 1/2, so the late-time evolution of RDE will be really like a phantom energy. Therefore, it seems that the big rip is inevitable in this model. On the other hand, the big rip is actually inconsistent with the theoretical framework of the holographic model of dark energy. To avoid the big rip, we appeal to the extra dimension physics. In this Letter, we investigate the cosmological evolution of the RDE in the braneworld cosmology. It is of interest to find that for the far future evolution of RDE in a Randall-Sundrum braneworld, there is an attractor solution where the steady state (de Sitter) finale occurs, in stead of the big rip.

Israel-Stewart Approach to Viscous Dissipative Extended Holographic Ricci Dark Energy Dominated Universe

Directory of Open Access Journals (Sweden)

Surajit Chattopadhyay

2016-01-01

Full Text Available This paper reports a study on the truncated Israel-Stewart formalism for bulk viscosity using the extended holographic Ricci dark energy (EHRDE. Under the consideration that the universe is dominated by EHRDE, the evolution equation for the bulk viscous pressure Π in the framework of the truncated Israel-Stewart theory has been taken as τΠ˙+Π=-3ξH, where τ is the relaxation time and ξ is the bulk viscosity coefficient. Considering effective pressure as a sum of thermodynamic pressure of EHRDE and bulk viscous pressure, it has been observed that under the influence of bulk viscosity the EoS parameter wDE is behaving like phantom, that is, wDE≤-1. It has been observed that the magnitude of the effective pressure peff=p+Π is decaying with time. We also investigated the case for a specific choice of scale factor; namely, a(t=(t-t0β/(1-α. For this choice we have observed that a transition from quintessence to phantom is possible for the equation of state parameter. However, the ΛCDM phase is not attainable by the state-finder trajectories for this choice. Finally it has been observed that in both of the cases the generalized second law of thermodynamics is valid for the viscous EHRDE dominated universe enveloped by the apparent horizon.

More on the holographic Ricci dark energy model: smoothing Rips through interaction effects?

Science.gov (United States)

Bouhmadi-López, Mariam; Errahmani, Ahmed; Ouali, Taoufik; Tavakoli, Yaser

2018-04-01

The background cosmological dynamics of the late Universe is analysed on the framework of a dark energy model described by an holographic Ricci dark energy component. Several kind of interactions between the dark energy and the dark matter components are considered herein. We solve the background cosmological dynamics for the different choices of interactions with the aim to analyse not only the current evolution of the universe but also its asymptotic behaviour and, in particular, possible future singularities removal. We show that in most of the cases, the Big Rip singularity, a finger print of this model in absence of an interaction between the dark sectors, is substituted by a de Sitter or a Minkowski state. Most importantly, we found two new future bouncing solutions leading to two possible asymptotic behaviours, we named Little Bang and Little Sibling of the Big Bang. At a Little Bang, as the size of the universe shrinks to zero in an infinite cosmic time, the Hubble rate and its cosmic time derivative blow up. In addition, at a Little sibling of the Big Bang, as the size of the universe shrinks to zero in an infinite cosmic time, the Hubble rate blows up but its cosmic time derivative is finite. These two abrupt events can happen as well in the past.

More on the holographic Ricci dark energy model: smoothing Rips through interaction effects?

Science.gov (United States)

Bouhmadi-López, Mariam; Errahmani, Ahmed; Ouali, Taoufik; Tavakoli, Yaser

2018-01-01

The background cosmological dynamics of the late Universe is analysed on the framework of a dark energy model described by an holographic Ricci dark energy component. Several kind of interactions between the dark energy and the dark matter components are considered herein. We solve the background cosmological dynamics for the different choices of interactions with the aim to analyse not only the current evolution of the universe but also its asymptotic behaviour and, in particular, possible future singularities removal. We show that in most of the cases, the Big Rip singularity, a finger print of this model in absence of an interaction between the dark sectors, is substituted by a de Sitter or a Minkowski state. Most importantly, we found two new future bouncing solutions leading to two possible asymptotic behaviours, we named Little Bang and Little Sibling of the Big Bang. At a Little Bang, as the size of the universe shrinks to zero in an infinite cosmic time, the Hubble rate and its cosmic time derivative blow up. In addition, at a Little sibling of the Big Bang, as the size of the universe shrinks to zero in an infinite cosmic time, the Hubble rate blows up but its cosmic time derivative is finite. These two abrupt events can happen as well in the past.

"Replaying Life's Tape": Simulations, metaphors, and historicity in Stephen Jay Gould's view of life.

Science.gov (United States)

Sepkoski, David

2016-08-01

In a famous thought experiment, Stephen Jay Gould asked whether, if one could somehow rewind the history of life back to its initial starting point, the same results would obtain when the "tape" was run forward again. This hypothetical experiment is generally understood as a metaphor supporting Gould's philosophy of evolutionary contingency, which he developed and promoted from the late 1980s until his death in 2002. However, there was a very literal, non-metaphorical inspiration for Gould's thought experiment: since the early 1970s, Gould, along with a group of other paleontologists, was actively engaged in attempts to model and reconstruct the history of life using computer simulations and database analysis. These simulation projects not only demonstrate the impact that computers had on data analysis in paleontology, but also shed light on the close relationship between models and empirical data in data-oriented science. In a sense, I will argue, the models developed by paleontologists through simulation and quantitative analysis of the empirical fossil record in the 1970s and beyond were literal attempts to "replay life's tape" by reconstructing the history of life as data. Copyright © 2015 Elsevier Ltd. All rights reserved.

Autecology of the tailed jay butterfly Graphium agamemnon (Lepidoptera : Rhopalocera : Papilionidae).

Science.gov (United States)

Ramana, S P Venkata; Atluri, J B; Reddi, C Subba

2003-07-01

The Tailed Jay Graphium agamemnon is one of the attractive papilionid butterflies that enliven the environment of Visakhapatnam. It occurs throughout the year. It lays eggs singly on young leaves of the mast tree Polyalthia longifolia var. pendula (Annonaceae). The eggs take 3-4 days to hatch. The larvae go through 5 instars over a period of 15-16 days. The pupal period is 13-14 days. The total period from egg to adult emergence spans over 33-36 days. Based on this short life cycle, and larval and pupal development success studied every month, this butterfly can be multivoltine with a minimum of 7-8 broods in a year. Both CI and GR decreased with the age of larva, their average figures being 3.78 and 0.43 respectively. AD values are high (average 92%) and decreased through successive instars. Both ECD and ECI followed a similar pattern with an increase from instar I up to II, then a decrease up to IV and again an increase in instar V and the highest value is with fifth instar. Adults frequently visited flowers (12-35 flowers in a min) spending 1.0 to 3.2 seconds on a flower. The nectar concentration ranged between 16 and 58%. Peak foraging activity mostly fell between 0900-1000 h. The proboscis received pollen in most of the floral species visited, thus satisfying one of the characteristics of butterfly pollination. Being a fast and strong flier it is treated as "high energy" pollinator promoting cross-pollination.

The Rocket Investigation of Current Closure in the Ionosphere (RICCI) mission: A novel application of CubeSats from a sounding rocket platform

Science.gov (United States)

Cohen, I. J.; Anderson, B. J.; Lessard, M.; Bonnell, J. W.; Bounds, S. R.; Lysak, R. L.; Erlandson, R. E.

2017-12-01

The transfer of energy and momentum between the terrestrial magnetosphere and ionosphere is substantially mediated by large-scale field-aligned currents (FACs), driven by magnetopause dynamics and magnetospheric pressures and closing through the ionosphere where the dissipation and drag are governed. While significant insight into ionospheric electrodynamics and the nature of magnetosphere-ionosphere (M-I) coupling have been gained by rocket and satellite measurements, in situ measurement of these ionospheric closure currents remains challenging. To date the best estimates of ionospheric current densities are inferred from ground-based radar observations combining electric fields calculated from drifts with conductivities derived from densities. RICCI aims to observe the structure of the ionospheric currents in situ to determine how the altitude structure of these currents is related to precipitation and density cavities, electromagnetic dynamics, and governs energy dissipation in the ionosphere. In situ measurement of the current density using multi-point measurements of the magnetic field requires precise attitude knowledge for which the only demonstrated technique is the use of star camera systems. The low vehicle rotation rates required for miniature commercial off-the-shelf (COTS) star cameras prohibit the use of available rocket sub-payload technologies at Wallops Flight Facility (WFF) which use high rates of spin to stabilize attitude. However, CubeSat attitude systems are already designed to achieve low vehicle rotation rates, so RICCI will use a set of three CubeSat sub-payloads deployed from a main low altitude payload with apogee of 160 km to provide precise current density measurement through the ionospheric closure altitude regime, together with a second rocket with apogee near 320 km to measure the incident input energy flux and convection electric field. The two rocket payloads and CubeSate sub-payloads are all instrumented with star cameras and

Benjamin Franklin a Jay Gatsby: Srovnání amerických literárních hrdinů, kteří se vypracovali vlastní silou

OpenAIRE

Korejtková, Adéla

2011-01-01

The thesis focuses on Benjamin Franklin, as he is portrayed in his Autobiography, and Jay Gatsby, the protagonist of Fitzgerald's The Great Gatsby, who are connected not only by being self-made men. Firstly, they are both symbolical figures that made a powerful commentary on a period, on the country and on its core myth - the American Dream. Secondly, they are linked by Fitzgerald himself since his hero creates a schedule and a table of general resolves which clearly imitate Franklin's schedu...

Stephen Jay Gould and the Value of Neutrality of Science During the Cold War.

Science.gov (United States)

Sheldon, Myrna

2016-12-01

Stephen Jay Gould was a paleontologist and scientific celebrity at the close of the twentieth century, most famous for his popular writings on evolution and his role in the American creationist controversies of that era. In the early 1980s, Gould was drawn into the "nuclear winter" episode through his friendship with Carl Sagan, an astronomer and popular science celebrity. Sagan helped develop the theory of nuclear winter and subsequently used the theory as evidence to petition the United States government to scale back its nuclear armament. The theory of nuclear winter claimed that even a small nuclear exchange could result in a atmospheric blackening akin to the extinction event of the late Cretaceous. Gould was not a climate scientist but he testified before the U.S. House of Representatives as an expert on historical extinction events. Gould's insistence on the value-neutrality of nuclear winter reveals much about the moral politics of science in late Cold War America. Coming at the heels of leftist scientific activism of the 1980s, the nuclear winter episode demonstrates how value-neutrality emerged the salient feature of scientific involvement in American politics in this period. Copyright © 2016 Elsevier Ltd. All rights reserved.

Haplosporidium nelsoni (MSX) in Japanese scallops Patinopecten yessoensis (Jay, 1857) from Dalian along the northern coast of the Yellow Sea, China.

Science.gov (United States)

Wang, Zhongwei; Lu, Xin; Liang, Yubo

2012-04-01

The protozoan parasite Haplosporidium nelsoni (MSX) was identified in Japanese scallops Patinopecten yessoensis (Jay, 1857) from Dalian along the northern coast of the Yellow Sea, China by histopathologic examination, polymerase chain reaction (PCR) amplification, and in situ hybridization (ISH) assay. H. nelsoni plasmodia-like structures were identified in the digestive glands of scallops by histologic examination, but no parasite spores were observed. PCR using the Hap-F2, R2 primer pair produced a sequence with 100% homology with the corresponding small subunit rDNA region of H. nelsoni. An ISH assay using the oligonucleotide probe MSX1347 produced a positive reaction with the Japanese scallop parasite. This is the first report of H. nelsoni in P. yessoensis in China.

Severe accident analysis of a steam generator tube rupture accident using MAAP-CANDU to support level 2 PSA for the Point Lepreau Generating Station Refurbishment Project

Energy Technology Data Exchange (ETDEWEB)

Petoukhov, S.M.; Brown, M.J. [Canadian Nuclear Laboratories, Chalk River, ON (Canada)

2015-07-01

A Level 2 Probabilistic Safety Assessment was performed for the Point Lepreau Generating Station. The MAAP-CANDU code was used to simulate the progression of postulated severe core damage accidents and fission product releases. This paper discusses the results for the reference case of the Steam Generator Tube Rupture initiating event. The reference case, dictated by the Level 2 Probabilistic Safety Assessment, was extreme and assumed most safety-related plant systems were not available: all steam generator feedwater; the emergency water supply; the moderator, shield and shutdown cooling systems; and all stages of emergency core cooling. The reference case also did not credit any post Fukushima lessons or any emergency mitigating equipment. The reference simulation predicted severe core damage beginning at 3.7 h, containment failure at 6.4 h, moderator boil off by 8.2 h, and calandria vessel failure at 42 h. A total release of 5.3% of the initial inventory of radioactive isotopes of Cs, Rb and I was predicted by the end of the simulation (139 h). Almost all noble gas fission products were released to the environment, primarily after the containment failure. No hydrogen/carbon monoxide burning was predicted. (author)

Yang-Mills instantons sitting on a Ricci-flat worldspace of double D4-branes

International Nuclear Information System (INIS)

Kim, Hongsu; Yoon, Yongsung

2001-01-01

Thus far, there seem to be no complete criteria that can settle the issue as to what the correct generalization of the Dirac-Born-Infeld (DBI) action, describing the low-energy dynamics of the D-branes, to the non-Abelian case would be. According to recent suggestions, one might pass the issue of worldvolume solitons from an Abelian to non-Abelian setting by considering the stack of multiple, coincident D-branes and use it as a guideline to construct or censor the relevant non-Abelian version of the DBI action. In this spirit, here we are interested in the explicit construction of SU(2) Yang-Mills (YM) instanton solutions in the background geometry of two coincident probe D4-brane worldspaces, particularly when the metric of the target spacetime in which the probe branes are embedded is given by the Ricci-flat, magnetic extremal 4-brane solution in type IIA supergravity theory with its worldspace metric being given by that of TaubendashNewman-Unti-Tamburino (NUT) and Eguchi-Hanson solutions, the two best-known gravitational instantons. Then we demonstrate that, with this YM instanton-gravitational instanton configuration on the probe D4-brane worldvolume, the energy of the probe branes attains its minimum value and hence enjoys a stable state provided one employs Tseytlin's non-Abelian DBI action for the description of multiple probe D-branes. In this way, we support the arguments in the literature in favor of Tseytlin's proposal for the non-Abelian DBI action

The development of caching and object permanence in Western scrub-jays (Aphelocoma californica): which emerges first?

Science.gov (United States)

Salwiczek, Lucie H; Emery, Nathan J; Schlinger, Barney; Clayton, Nicola S

2009-08-01

Recent studies on the food-caching behavior of corvids have revealed complex physical and social skills, yet little is known about the ontogeny of food caching in relation to the development of cognitive capacities. Piagetian object permanence is the understanding that objects continue to exist even when they are no longer visible. Here, the authors focus on Piagetian Stages 3 and 4, because they are hallmarks in the cognitive development of both young children and animals. Our aim is to determine in a food-caching corvid, the Western scrub-jay, whether (1) Piagetian Stage 4 competence and tentative caching (i.e., hiding an item invisibly and retrieving it without delay), emerge concomitantly or consecutively; (2) whether experiencing the reappearance of hidden objects enhances the timing of the appearance of object permanence; and (3) discuss how the development of object permanence is related to behavioral development and sensorimotor intelligence. Our findings suggest that object permanence Stage 4 emerges before tentative caching, and independent of environmental influences, but that once the birds have developed simple object-permanence, then social learning might advance the interval after which tentative caching commences. Copyright 2009 APA, all rights reserved.

Towards large volume big divisor D3/D7 " μ-split supersymmetry" and Ricci-flat Swiss-cheese metrics, and dimension-six neutrino mass operators

Science.gov (United States)

Dhuria, Mansi; Misra, Aalok

2012-02-01

We show that it is possible to realize a " μ-split SUSY" scenario (Cheng and Cheng, 2005) [1] in the context of large volume limit of type IIB compactifications on Swiss-cheese Calabi-Yau orientifolds in the presence of a mobile space-time filling D3-brane and a (stack of) D7-brane(s) wrapping the "big" divisor. For this, we investigate the possibility of getting one Higgs to be light while other to be heavy in addition to a heavy higgsino mass parameter. Further, we examine the existence of long lived gluino that manifests one of the major consequences of μ-split SUSY scenario, by computing its decay width as well as lifetime corresponding to the three-body decays of the gluino into either a quark, a squark and a neutralino or a quark, squark and goldstino, as well as two-body decays of the gluino into either a neutralino and a gluon or a goldstino and a gluon. Guided by the geometric Kähler potential for Σ obtained in Misra and Shukla (2010) [2] based on GLSM techniques, and the Donaldson's algorithm (Barun et al., 2008) [3] for obtaining numerically a Ricci-flat metric, we give details of our calculation in Misra and Shukla (2011) [4] pertaining to our proposed metric for the full Swiss-cheese Calabi-Yau (the geometric Kähler potential being needed to be included in the full moduli space Kähler potential in the presence of the mobile space-time filling D3-brane), but for simplicity of calculation, close to the big divisor, which is Ricci-flat in the large volume limit. Also, as an application of the one-loop RG flow solution for the higgsino mass parameter, we show that the contribution to the neutrino masses at the EW scale from dimension-six operators arising from the Kähler potential, is suppressed relative to the Weinberg-type dimension-five operators.

Towards large volume big divisor D3/D7 “μ-split supersymmetry” and Ricci-flat Swiss-cheese metrics, and dimension-six neutrino mass operators

International Nuclear Information System (INIS)

Dhuria, Mansi; Misra, Aalok

2012-01-01

We show that it is possible to realize a “μ-split SUSY” scenario (Cheng and Cheng, 2005) in the context of large volume limit of type IIB compactifications on Swiss-cheese Calabi-Yau orientifolds in the presence of a mobile space-time filling D3-brane and a (stack of) D7-brane(s) wrapping the “big” divisor. For this, we investigate the possibility of getting one Higgs to be light while other to be heavy in addition to a heavy higgsino mass parameter. Further, we examine the existence of long lived gluino that manifests one of the major consequences of μ-split SUSY scenario, by computing its decay width as well as lifetime corresponding to the three-body decays of the gluino into either a quark, a squark and a neutralino or a quark, squark and goldstino, as well as two-body decays of the gluino into either a neutralino and a gluon or a goldstino and a gluon. Guided by the geometric Kähler potential for Σ B obtained in Misra and Shukla (2010) based on GLSM techniques, and the Donaldson's algorithm (Barun et al., 2008) for obtaining numerically a Ricci-flat metric, we give details of our calculation in Misra and Shukla (2011) pertaining to our proposed metric for the full Swiss-cheese Calabi-Yau (the geometric Kähler potential being needed to be included in the full moduli space Kähler potential in the presence of the mobile space-time filling D3-brane), but for simplicity of calculation, close to the big divisor, which is Ricci-flat in the large volume limit. Also, as an application of the one-loop RG flow solution for the higgsino mass parameter, we show that the contribution to the neutrino masses at the EW scale from dimension-six operators arising from the Kähler potential, is suppressed relative to the Weinberg-type dimension-five operators.

Influence of corticosterone treatment on nestling begging in Florida scrub-jays (Aphelocoma coerulescens).

Science.gov (United States)

Elderbrock, Emily K; Small, Thomas W; Schoech, Stephan J

2018-04-01

Altricial young are dependent on adults for protection and food, and they display nutritional need by begging to elicit feeding from parents. Begging at high levels can be energetically expensive and attract predators; thus, an individual must balance its nutritional needs with these potential costs. Further, because a parent is limited in the amount of food it can provide, begging can contribute to both parent-offspring conflict and sibling-sibling competition. Many extrinsic and intrinsic factors may contribute to begging behavior. One intrinsic factor of interest is corticosterone (CORT), a metabolic hormone hypothesized to play a role in regulating a nestling's begging behavior. We investigated the hypothesis that increased exposure to CORT influences nestling begging behavior in an altricial species, the Florida scrub-jay (Aphelocoma coerulescens). We treated one nestling per treatment nest with a twice-daily dose of exogenous hormone via a CORT-injected waxworm, whereas a second individual received a vehicle-injected waxworm. We monitored individual nestling and adult behavior at all nests with the use of high-definition video cameras on several days during treatment. We found no difference in begging rate between CORT fed and vehicle fed nestlings within a treatment nest. Further, to determine whether CORT treatment had indirect effects on the entire brood, we monitored additional nests, in which nestlings were not manipulated. When treatment and controls were compared, overall begging rates of nestlings in treatment nests were greater than those in control nests. This result suggests that CORT treatment of an individual altered its behavior, as well as that of its siblings. Copyright © 2017 Elsevier Inc. All rights reserved.

Stephen Jay Kline on systems, or physics, complex systems, and the gap between.

Energy Technology Data Exchange (ETDEWEB)

Campbell, Philip LaRoche

2011-06-01

At the end of his life, Stephen Jay Kline, longtime professor of mechanical engineering at Stanford University, completed a book on how to address complex systems. The title of the book is 'Conceptual Foundations of Multi-Disciplinary Thinking' (1995), but the topic of the book is systems. Kline first establishes certain limits that are characteristic of our conscious minds. Kline then establishes a complexity measure for systems and uses that complexity measure to develop a hierarchy of systems. Kline then argues that our minds, due to their characteristic limitations, are unable to model the complex systems in that hierarchy. Computers are of no help to us here. Our attempts at modeling these complex systems are based on the way we successfully model some simple systems, in particular, 'inert, naturally-occurring' objects and processes, such as what is the focus of physics. But complex systems overwhelm such attempts. As a result, the best we can do in working with these complex systems is to use a heuristic, what Kline calls the 'Guideline for Complex Systems.' Kline documents the problems that have developed due to 'oversimple' system models and from the inappropriate application of a system model from one domain to another. One prominent such problem is the Procrustean attempt to make the disciplines that deal with complex systems be 'physics-like.' Physics deals with simple systems, not complex ones, using Kline's complexity measure. The models that physics has developed are inappropriate for complex systems. Kline documents a number of the wasteful and dangerous fallacies of this type.

Falling from the Past. Geographies of exceptionalism in two novels by Jay McInerney

Directory of Open Access Journals (Sweden)

Fiorenzo Iuliano

2011-09-01

Full Text Available Celebrating the glamorous 1980s, Jay McInerney has described the fall of the ambitions and delusions of yuppies in New York City. The vibrant atmosphere of his debut novel (Bright Lights, Big City, 1984 comes to a sudden end in Brightness Falls (1987, where the 1987 stock market crash is prophesied and narrated in its consequences on the lives of a young, brilliant couple, Corrine and Russell Calloway. Almost twenty years later, in The Good Life (2006, McInerney takes up Russell’s and Corrine’s stories again, now in the aftermath of September 11. This article focuses on the symbolic economy of the US territory. The 1980s, as they have been represented in Brightness Falls, witnessed the boisterous celebration of New York City and its centrality in the imaginary geography of the USA. When New York apparently starts crumbling under the terrorist attacks, the protagonists of The Good Life ideally (and sometimes physically go back to their native places. In particular, one of the novel’s central characters, Luke McGavock, who starts an affair with Corrine while they are both volunteering at Ground Zero, returns to his native Tennessee, where is confronted with the memory of the Civil War. From this moment on, the novel starts tracing an implicit and highly thought-provoking parallel between the defeated nineteenth-century South and the synecdochic New York City at the turn of the twenty-first century, whose crash has engendered the dramatic need for the US to face the burden of its own history.

Studying ventricular abnormalities in mild cognitive impairment with hyperbolic Ricci flow and tensor-based morphometry.

Science.gov (United States)

Shi, Jie; Stonnington, Cynthia M; Thompson, Paul M; Chen, Kewei; Gutman, Boris; Reschke, Cole; Baxter, Leslie C; Reiman, Eric M; Caselli, Richard J; Wang, Yalin

2015-01-01

Mild Cognitive Impairment (MCI) is a transitional stage between normal aging and dementia and people with MCI are at high risk of progression to dementia. MCI is attracting increasing attention, as it offers an opportunity to target the disease process during an early symptomatic stage. Structural magnetic resonance imaging (MRI) measures have been the mainstay of Alzheimer's disease (AD) imaging research, however, ventricular morphometry analysis remains challenging because of its complicated topological structure. Here we describe a novel ventricular morphometry system based on the hyperbolic Ricci flow method and tensor-based morphometry (TBM) statistics. Unlike prior ventricular surface parameterization methods, hyperbolic conformal parameterization is angle-preserving and does not have any singularities. Our system generates a one-to-one diffeomorphic mapping between ventricular surfaces with consistent boundary matching conditions. The TBM statistics encode a great deal of surface deformation information that could be inaccessible or overlooked by other methods. We applied our system to the baseline MRI scans of a set of MCI subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI: 71 MCI converters vs. 62 MCI stable). Although the combined ventricular area and volume features did not differ between the two groups, our fine-grained surface analysis revealed significant differences in the ventricular regions close to the temporal lobe and posterior cingulate, structures that are affected early in AD. Significant correlations were also detected between ventricular morphometry, neuropsychological measures, and a previously described imaging index based on fluorodeoxyglucose positron emission tomography (FDG-PET) scans. This novel ventricular morphometry method may offer a new and more sensitive approach to study preclinical and early symptomatic stage AD. Copyright © 2014 Elsevier Inc. All rights reserved.

Circulating carotenoid concentrations are positively correlated with later clutch initiation in Florida Scrub-Jays (Aphelocoma coerulescens).

Science.gov (United States)

Heiss, Rebecca S; Cohen, Alan A; Bowman, Reed; Boughton, Raoul K; Bridge, Eli; McGraw, Kevin J; Schoech, Stephan J

2011-02-01

Antioxidants play key roles in preventing free radical damage to various molecules, cells, and tissues, but it is not well understood how variation in antioxidant levels may relate to the reproductive success or health of wild animals. We explored the relationship between circulating antioxidant concentrations and both body condition and timing of reproduction in male and female Florida Scrub-Jays (Aphelocoma coerulescens), a cooperatively breeding passerine bird. We examined whether levels of uric acid, vitamin E, and carotenoids (all potentially important antioxidants) were linked to body condition and timing of reproduction, two measures that are directly related to reproductive success. Antioxidant concentrations were not correlated with body condition, but they were related to timing of first clutch initiation, though not always in the predicted direction. Elevated circulating levels of carotenoids were associated with delayed clutch initiation in female breeders. Relatively higher vitamin E levels in control birds were associated with earlier clutch initiation, whereas male breeders that received long-term food supplementation had elevated levels of vitamin E and delayed reproduction. Several potential explanations for the link between elevated levels of antioxidants and delayed clutch initiation are discussed. Separate explanations for each sex include, but are not limited to, oxidative stress as a result of territory defense efforts in males, different dietary regimes due to supplementation, and mobilized plasma antioxidants in females that were coping with a stressor. © 2010 Wiley-Liss, Inc.

California scrub-jays reduce visual cues available to potential pilferers by matching food colour to caching substrate.

Science.gov (United States)

Kelley, Laura A; Clayton, Nicola S

2017-07-01

Some animals hide food to consume later; however, these caches are susceptible to theft by conspecifics and heterospecifics. Caching animals can use protective strategies to minimize sensory cues available to potential pilferers, such as caching in shaded areas and in quiet substrate. Background matching (where object patterning matches the visual background) is commonly seen in prey animals to reduce conspicuousness, and caching animals may also use this tactic to hide caches, for example, by hiding coloured food in a similar coloured substrate. We tested whether California scrub-jays ( Aphelocoma californica ) camouflage their food in this way by offering them caching substrates that either matched or did not match the colour of food available for caching. We also determined whether this caching behaviour was sensitive to social context by allowing the birds to cache when a conspecific potential pilferer could be both heard and seen (acoustic and visual cues present), or unseen (acoustic cues only). When caching events could be both heard and seen by a potential pilferer, birds cached randomly in matching and non-matching substrates. However, they preferentially hid food in the substrate that matched the food colour when only acoustic cues were present. This is a novel cache protection strategy that also appears to be sensitive to social context. We conclude that studies of cache protection strategies should consider the perceptual capabilities of the cacher and potential pilferers. © 2017 The Author(s).

Towards Large Volume Big Divisor D3-D7 "mu-Split Supersymmetry" and Ricci-Flat Swiss-Cheese Metrics, and Dimension-Six Neutrino Mass Operators

CERN Document Server

Dhuria, Mansi

2012-01-01

We show that it is possible to realize a "mu-split SUSY" scenario [1] in the context of large volume limit of type IIB compactifications on Swiss-Cheese Calabi-Yau's in the presence of a mobile space-time filling D3-brane and a (stack of) D7-brane(s) wrapping the "big" divisor Sigma_B. For this, we investigate the possibility of getting one Higgs to be light while other to be heavy in addition to a heavy Higgsino mass parameter. Further, we examine the existence of long lived gluino that manifests one of the major consequences of mu-split SUSY scenario, by computing its decay width as well as lifetime corresponding to the 3-body decays of the gluino into a quark, a squark and a neutralino or Goldstino, as well as 2-body decays of the gluino into either a neutralino or a Goldstino and a gluon. Guided by the geometric Kaehler potential for Sigma_B obtained in [2] based on GLSM techniques, and the Donaldson's algorithm [3] for obtaining numerically a Ricci-flat metric, we give details of our calculation in [4] p...

Nuclear power in New Brunswick

International Nuclear Information System (INIS)

O'Connor, A.J.

1984-06-01

New Brunswick Power is a medium-utility with gross production for the past fiscal year for domestic and external sales of about 16.5 billion kilowatt hours. Of this figure 33.5% was supplied through nuclear generation. The financial risks involved with the production of the Point Lepreau nuclear generating station were discussed. Further, questions of assurances given for schedule and cost, licencing, and long-term plant performance of the Point Lepreau no. 2 unit were addressed. These were discussed with particular emphasis on the competition for the New England market

Power exports - a U.S. market for CANDU (question mark)

International Nuclear Information System (INIS)

McIntyre, H.C.

1982-01-01

The advantages to both countries of power exports from Canada to the U.S.A. are explained. The policy of the Canadian federal government now tends to favour such exports. While Hydro-Quebec leads in exports, Ontario Hydro plans to sell 1.2 GW of coal-generated power to New Jersey. New Brunswick now has applications before the National Energy Board for export of 0.35 GW from Point Lepreau. A second 0.6 GW unit at Point Lepreau, dedicated to the export of electricity, has been suggested

This view of science: Stephen Jay Gould as historian of science and scientific historian, popular scientist and scientific popularizer.

Science.gov (United States)

Shermer, Michael B

2002-08-01

Science historian Ronald Numbers once remarked that the two most influential historians of science of the 20th century were Thomas Kuhn and Stephen Jay Gould. All historians are deeply familiar with Kuhn's work and influence, and most know of the remarkable impact Gould has had on evolutionary theory through both his professional and popular works. But little attention has been paid to the depth, scope, and importance of Gould's rôle as historian and philosopher of science, and his use of popular science exposition to reinforce old knowledge and generate new. This paper presents the results of an extensive quantitative content analysis of Gould's 22 books, 101 book reviews, 479 scientific papers, and 300 Natural History essays, in terms of their subject matter (Evolutionary Theory, History and Philosophy of Science, Natural History, Paleontology/Geology, Social Science/Commentary), and thematic dichotomies (Theory-Data, Time's Arrow-Time's Cycle, Adaptationism- Nonadaptationalism, Punctuationism-Gradualism, Contingency-Necessity). Special emphasis is placed on the interaction between the subjects and themata, how Gould has used the history of science to reinforce his evolutionary theory (and vice versa), and how his philosophy of science has influenced both his evolutionary theory and his historiography. That philosophy can best be summed up in a quotation from Charles Darwin, frequently cited by Gould: 'All observation must be for or against some view if it is to be of any service'. Gould followed Darwin's advice throughout his career, including his extensive writings on the history and philosophy of science.

Intervention of the Canadian Nuclear Association to the National Energy Board

International Nuclear Information System (INIS)

1982-01-01

This submission from the Canadian Nuclear Association to the National Energy Board of Canada was made in support of the application by the New Brunswick Electric Power Commission to increase its electricity exports from the Point Lepreau nuclear station to the New England states from 205 MW to 335 MW. The Canadian Nuclear Association felt that their support was justified in view of the fact that the CANDU nuclear reactor had proven itself to be a safe, reliable and economic source of electric generation. They felt the 630 MW CANDU station at Point Lepreau, New Brunswick would have sufficient generating capacity to export 335 MW for a ten-year period

Diet and feeding behavior of the White-naped Jay, Cyanocorax cyanopogon (Wied, 1821 (Aves, Passeriformes, Corvidae in a disturbed environment in central Brazil

Directory of Open Access Journals (Sweden)

RAM Barros

Full Text Available The White-naped Jay Cyanocorax cyanopogon (Wied, 1821 is an omnivorous and opportunistic species, with a multifarious diet. In view of the scarcity of available data in the literature, the aim was to investigate and describe the bird's diet, location of food items, foraging tactics, actual feeding behavior and intraspecific interactions, as a means of defining the items consumed. The study was carried out in a Cerrado area in the Araguaia Campus of the Federal University of Mato Grosso – UFMT, in Pontal do Araguaia, Mato Grosso State, Brazil, from August to December, 2006, and from April to October, 2010. All the feeding events were recorded through 136 hours of animal focal sampling, whereby it was shown that these birds predominantly consume animal nutrients, replenished by vegetable items and human food-waste. Arthropods were predominant in the diet, with ants as the most abundant and frequent item. The fruits, flowers and seeds of eleven plant species were also consumed. Food-waste, representing about 1/10 of the total, was constantly consumed even when other food sources were available. Although active among the various strata, foraging is mainly on the ground. In the event of food-scarcity, the strategy employed is the hierarchical deployment of the members of various-sized groups, with the avoidance of direct competition. This versatility during all seasons, confirms total adaptation to the anthropic environment surrounded by native habitats that characterized the study site.

Recent topics in differential and analytic geometry

CERN Document Server

Ochiai, T

1990-01-01

Advanced Studies in Pure Mathematics, Volume 18-I: Recent Topics in Differential and Analytic Geometry presents the developments in the field of analytical and differential geometry. This book provides some generalities about bounded symmetric domains.Organized into two parts encompassing 12 chapters, this volume begins with an overview of harmonic mappings and holomorphic foliations. This text then discusses the global structures of a compact Kähler manifold that is locally decomposable as an isometric product of Ricci-positive, Ricci-negative, and Ricci-flat parts. Other chapters con

Ingredients for sustained excellence

International Nuclear Information System (INIS)

Johnson, A.R.; Alikhan, S.; Steed, R.G.

1992-01-01

Point Lepreau, a 680MWe CANDU reactor, has, since startup, been one of the world's best performing reactors. Many of the ingredients for this success can be found at other plants, but Pt Lepreau has found a ''chemistry'' that has sustained its performance at a very high level. Our belief is that this is the result of two major influences: Pt Lepreau is the only nuclear unit in a small utility, all its nuclear expertise exists at the station, and all necessary disciplines can be readily galvanized to solve problems and get work done. The structure of the organization is simple, with station management involvement in day to day activities. This fosters accountability and a natural efficiency that does not need slogans to achieve its purpose. Turning to the factors that have contributed to the station's success, the IAEA's technical exchange visit in July 1990 identified four items ''which are particularly noteworthy since they can be developed and used widely in the nuclear industry to enhance safety and availability. These are: quality assurance applications; the degree to which system engineers are employed; the dedication of skilled resources to and thoroughness of outage planning; and the in-house development of computers to assist directly in the day to day, medium and long term management of the generating station''. (Author)

Endangered and Threatened Species at Kennedy Space Center Merritt Island National Wildlife Refuge

Science.gov (United States)

Galdolfi, Catherine

2010-01-01

Throughout my internship, I assisted with the long-term monitoring of the Florida Scrub- Jay (Aphelocoma coerulescens), a threatened species endemic to Florida. The Florida Scrub Jay diet consists of insects and small vertebrates throughout most of the year; however, during the winter their primary diet is acorns because the insect population is low. Furthermore, the Florida Scrub-Jay is a habitat specialist that lives in a disappearing plant community called the scrub, which consists of sand live oak, myrtle oak and chapman oak. The Florida Scrub-Jay is considered threatened because its numbers are decreasing primarily due to the loss of habitat that it needs to survive. Scrub habitat is highly desirable for human development because it is high, dry, and sandy. Periodic controlled burns maintain the scrub in a low, open condition favored by Scrub-Jays. Florida Scrub-Jays build their nests approximately 3-5 feet (approximately 1.5 m) above the ground in shrubby oaks (Breininger 153), mate for life and are cooperative breeders; which means that the young jays remain in their natal territory for at least a year to help their parents defend their territory, feed the young, and mob predators. (Breininger 152). I assisted in conducting monthly censuses at long-term monitoring sites and a juvenile in July survey to determine reproductive success for the year. In addition, to Scrub-Jay monitoring, I also had the opportunity to assist with some long term monitoring of ecosystem recovery. Scrub is a fire maintained system. Fire maintains the structure of scrub necessary for many of the threatened species that reside in the scrub habitat.

Local gradient estimate for harmonic functions on Finsler manifolds

OpenAIRE

Xia, Chao

2013-01-01

In this paper, we prove the local gradient estimate for harmonic functions on complete, noncompact Finsler measure spaces under the condition that the weighted Ricci curvature has a lower bound. As applications, we obtain Liouville type theorem on Finsler manifolds with nonnegative Ricci curvature.

Untitled

Indian Academy of Sciences (India)

of pairs of spinless particle-antiparticle due to expansion of the early universe in the vacuum state (provided by temperature dependent Coleman-Weinberg like potential for Ricci field), where spontaneous symmetry breaking takes place. Keywords. R gravity; dual nature of Ricci scalar; early Universe; particle production.

A Riemannian scalar measure for diffusion tensor images

NARCIS (Netherlands)

Astola, L.J.; Fuster, A.; Florack, L.M.J.

2010-01-01

We study a well-known scalar quantity in Riemannian geometry, the Ricci scalar, in the context of Diffusion Tensor Imaging (DTI), which is an emerging non-invasive medical imaging modality. We derive a physical interpretation for the Ricci scalar and explore experimentally its significance in DTI.

A new approach toward geometrical concept of black hole thermodynamics

Energy Technology Data Exchange (ETDEWEB)

Hendi, Seyed Hossein [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Panahiyan, Shahram; Panah, Behzad Eslam; Momennia, Mehrab [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)

2015-10-15

Motivated by the energy representation of Riemannian metric, in this paper we study different approaches toward the geometrical concept of black hole thermodynamics. We investigate thermodynamical Ricci scalar of Weinhold, Ruppeiner and Quevedo metrics and show that their number and location of divergences do not coincide with phase transition points arisen from heat capacity. Next, we introduce a new metric to solve these problems. We show that the denominator of the Ricci scalar of the new metric contains terms which coincide with different types of phase transitions. We elaborate the effectiveness of the new metric and shortcomings of the previous metrics with some examples. Furthermore, we find a characteristic behavior of the new thermodynamical Ricci scalar which enables one to distinguish two types of phase transitions. In addition, we generalize the new metric for the cases of more than two extensive parameters and show that in these cases the divergencies of thermodynamical Ricci scalar coincide with phase transition points of the heat capacity. (orig.)

A new approach toward geometrical concept of black hole thermodynamics

International Nuclear Information System (INIS)

Hendi, Seyed Hossein; Panahiyan, Shahram; Panah, Behzad Eslam; Momennia, Mehrab

2015-01-01

Motivated by the energy representation of Riemannian metric, in this paper we study different approaches toward the geometrical concept of black hole thermodynamics. We investigate thermodynamical Ricci scalar of Weinhold, Ruppeiner and Quevedo metrics and show that their number and location of divergences do not coincide with phase transition points arisen from heat capacity. Next, we introduce a new metric to solve these problems. We show that the denominator of the Ricci scalar of the new metric contains terms which coincide with different types of phase transitions. We elaborate the effectiveness of the new metric and shortcomings of the previous metrics with some examples. Furthermore, we find a characteristic behavior of the new thermodynamical Ricci scalar which enables one to distinguish two types of phase transitions. In addition, we generalize the new metric for the cases of more than two extensive parameters and show that in these cases the divergencies of thermodynamical Ricci scalar coincide with phase transition points of the heat capacity. (orig.)

Ametnikule kohustuslik! / Siim Sukles

Index Scriptorium Estoniae

Sukles, Siim

2007-01-01

Rets. rmt: Lynn, Jonathan, Jay, Anthony. Jah, härra minister / tlk. Juhan Kahk. Tallinn : Varrak, 2007 ; Lynn, Jonathan, Jay, Anthony. Jah, härra peaminister / tlk. Juhan Kahk. Tallinn : Varrak, 2007

Implementation of an Improved Safe Operating Envelope

International Nuclear Information System (INIS)

Prime, Robyn; McIntyre, Mark; Reeves, David

2008-01-01

This paper is a continuation of the paper presented at IYNC 2004 on 'The Definition of a Safe Operating Envelope'. The current paper concentrates on the implementation process of the Safe Operating Envelope employed at the Point Lepreau Generating Station. (authors)

Implementation of an Improved Safe Operating Envelope

Energy Technology Data Exchange (ETDEWEB)

Prime, Robyn; McIntyre, Mark [NB Power Nuclear, P.O. Box 600, Lepreau, NB (Canada); Reeves, David [Atlantic Nuclear Services Ltd., PO Box 1268 Fredericton, NB (Canada)

2008-07-01

This paper is a continuation of the paper presented at IYNC 2004 on 'The Definition of a Safe Operating Envelope'. The current paper concentrates on the implementation process of the Safe Operating Envelope employed at the Point Lepreau Generating Station. (authors)

A study of Para-Sasakian manifold

International Nuclear Information System (INIS)

Rahman, M.S.

1995-08-01

A Para-Sasakian manifold M is viewed in the light of an almost paracontact manifold. The fundamental concepts of M in spirit to Recurrent, Ricci-recurrent, 2-Recurrent and 2-Ricci-recurrent manifolds are presented. An η-Einstein manifold modelled on P-Sasakian manifold is then treated with simplified proofs of some results. (author). 7 refs

A priori estimates and existence for a class of fully nonlinear elliptic equations in conformal geometry

OpenAIRE

Wang, Xu-Jia

2006-01-01

In this paper we prove the interior gradient and second derivative estimates for a class of fully nonlinear elliptic equations determined by symmetric functions of eigenvalues of the Ricci or Schouten tensors. As an application we prove the existence of solutions to the equations when the manifold is locally conformally flat or the Ricci curvature is positive.

Educational partnerships - a win win endeavor!

International Nuclear Information System (INIS)

Munro, R.A.

1996-01-01

This paper is largely concerned with the New Brunswick teacher placement project. Groups of teachers have visited Point Lepreau Nuclear Generating Station, where they have learned more about nuclear energy, and have helped to improve public affairs material and exhibits aimed at school children

Conformal Vector Fields on Doubly Warped Product Manifolds and Applications

Directory of Open Access Journals (Sweden)

H. K. El-Sayied

2016-01-01

Full Text Available This article aimed to study and explore conformal vector fields on doubly warped product manifolds as well as on doubly warped spacetime. Then we derive sufficient conditions for matter and Ricci collineations on doubly warped product manifolds. A special attention is paid to concurrent vector fields. Finally, Ricci solitons on doubly warped product spacetime admitting conformal vector fields are considered.

Power in the Maritimes

International Nuclear Information System (INIS)

Anon.

1977-01-01

This article highlights generation and transmission developments in Atlantic Canada, up-dates current projects and future planning, and features authoritative statements by utility executives about the energy situation in the Maritime provinces. Some details of the Point Lepreau 630 MW CANDU reactor are given. (N.D.H.)

A Congruence Theorem for Minimal Surfaces in $S^{5}$ with Constant Contact Angle

OpenAIRE

Montes, Rodrigo Ristow; Verderesi, Jose A.

2006-01-01

We provide a congruence theorem for minimal surfaces in $S^5$ with constant contact angle using Gauss-Codazzi-Ricci equations. More precisely, we prove that Gauss-Codazzi-Ricci equations for minimal surfaces in $S^5$ with constant contact angle satisfy an equation for the Laplacian of the holomorphic angle. Also, we will give a characterization of flat minimal surfaces in $S^5$ with constant contact angle.

Some theorems on a class of harmonic manifolds

International Nuclear Information System (INIS)

Rahman, M.S.; Chen Weihuan.

1993-08-01

A class of harmonic n-manifold, denoted by HM n , is, in fact, focussed on a Riemannian manifold with harmonic curvature. A variety of results, with properties, on HM n is presented in a fair order. Harmonic manifolds are then touched upon manifolds with recurrent Ricci curvature, biRicci-recurrent curvature and recurrent conformal curvature, and, in consequence, a sequence of theorems are deduced. (author). 21 refs

Mobbing calls signal predator category in a kin group-living bird species

Science.gov (United States)

Griesser, Michael

2009-01-01

Many prey species gather together to approach and harass their predators despite the associated risks. While mobbing, prey usually utter calls and previous experiments have demonstrated that mobbing calls can convey information about risk to conspecifics. However, the risk posed by predators also differs between predator categories. The ability to communicate predator category would be adaptive because it would allow other mobbers to adjust their risk taking. I tested this idea in Siberian jays Perisoreus infaustus, a group-living bird species, by exposing jay groups to mounts of three hawk and three owl species of varying risks. Groups immediately approached to mob the mount and uttered up to 14 different call types. Jays gave more calls when mobbing a more dangerous predator and when in the presence of kin. Five call types were predator-category-specific and jays uttered two hawk-specific and three owl-specific call types. Thus, this is one of the first studies to demonstrate that mobbing calls can simultaneously encode information about both predator category and the risk posed by a predator. Since antipredator calls of Siberian jays are known to specifically aim at reducing the risk to relatives, kin-based sociality could be an important factor in facilitating the evolution of predator-category-specific mobbing calls. PMID:19474047

Mobbing calls signal predator category in a kin group-living bird species.

Science.gov (United States)

Griesser, Michael

2009-08-22

Many prey species gather together to approach and harass their predators despite the associated risks. While mobbing, prey usually utter calls and previous experiments have demonstrated that mobbing calls can convey information about risk to conspecifics. However, the risk posed by predators also differs between predator categories. The ability to communicate predator category would be adaptive because it would allow other mobbers to adjust their risk taking. I tested this idea in Siberian jays Perisoreus infaustus, a group-living bird species, by exposing jay groups to mounts of three hawk and three owl species of varying risks. Groups immediately approached to mob the mount and uttered up to 14 different call types. Jays gave more calls when mobbing a more dangerous predator and when in the presence of kin. Five call types were predator-category-specific and jays uttered two hawk-specific and three owl-specific call types. Thus, this is one of the first studies to demonstrate that mobbing calls can simultaneously encode information about both predator category and the risk posed by a predator. Since antipredator calls of Siberian jays are known to specifically aim at reducing the risk to relatives, kin-based sociality could be an important factor in facilitating the evolution of predator-category-specific mobbing calls.

“Like the Hebrews in Spain”: The Jesuit Encounter with Muslims in China and the Problem of Cultural Change

Directory of Open Access Journals (Sweden)

Ben-Dor Benite, Zvi

2015-12-01

Full Text Available This essay is concerned with the possibility of cultural change in the writings of Matteo Ricci. In order to elucidate this question, this essay discusses aspects of Matteo Ricci’s perception of Islam and Muslims in China and identifies the moments when they changed. I show that over time Ricci developed a much more nuanced perception of Islam in China, but argue still that his views remained quite limited because of lack of dialogue with Muslims he saw in China. These limitations, I also argue, reflect the limitations of European views of Islam in the early modern Euro-Mediterranean world. Recognizing these limitations, I suggest, might help us to develop new approaches to questions of religion in early modern China.Este trabajo trata de las posibilidades del cambio cultural en los escritos de Matteo Ricci. Para poder conocer mejor esta cuestión, este estudio discute diversos aspectos de la percepción de Matteo Ricci sobre el Islam y los musulmanes en China, identificando los momentos en los que cambia. He podido mostrar cómo, a lo largo del tiempo, Ricci desarrolló una percepción cada vez más matizada del Islam en China, pero sostengo que sus opiniones se mantuvieron bastante fijas debido a su falta de diálogo con los musulmanes de esa zona. Esta percepción tiene mucho que ver con los limitados puntos de vista del Islam en la Europa mediterránea moderna. Conocer estas limitaciones, sugiero, nos podrá ayudar a desarrollar nuevos enfoques sobre la investigación de la religión en China.

Regional Education Profile: Asia. China, Hong Kong, Macau, Thailand, Indonesia, Malaysia, Brunei.

Science.gov (United States)

Institute of International Education, New York, NY.

Developments in international education in Asia during 1985 are considered in three essays presented in the Biennial International Education Seminars conducted by the Institute of International Education. Countries covered by the essays and the authors are: China, Hong Kong, and Thailand (Jay Henderson); Macau (Josef Silny and Jay Henderson); and…

On complete manifolds supporting a weighted Sobolev type inequality

International Nuclear Information System (INIS)

Adriano, Levi; Xia Changyu

2011-01-01

Highlights: → We study manifolds supporting a weighted Sobolev or log-Sobolev inequality. → We investigate manifolds of asymptotically non-negative Ricci curvature. → The constant in the weighted Sobolev inequality on complete manifolds is studied. - Abstract: This paper studies the geometric and topological properties of complete open Riemannian manifolds which support a weighted Sobolev or log-Sobolev inequality. We show that the constant in the weighted Sobolev inequality on a complete open Riemannian manifold should be bigger than or equal to the optimal one on the Euclidean space of the same dimension and that a complete open manifold of asymptotically non-negative Ricci curvature supporting a weighted Sobolev inequality must have large volume growth. We also show that a complete manifold of non-negative Ricci curvature on which the log-Sobolev inequality holds is not very far from the Euclidean space.

New Brunswick Power Nuclear Corporation update 2005

International Nuclear Information System (INIS)

White, R.M.; Eagles, E.R.; Pilkington, W.S.

2005-01-01

A brief presentation will be made on the operations and business activities over the previous year with a discussion of the current status of the NB Power group of companies. The New Brunswick Government has implemented the new 'Electricity Act' which has resulted restructuring of NB Power, opening of the electricity market to wholesale completion and the separation of the transmission system operation from NB Power. On October 1, 2005 the restructuring of NB Power was implemented to change NB Power from a single integrated utility into NB Power Holding Corporation with four subsidiary operating companies including NB Power Nuclear Corporation, NB Power Distribution and Customer Service Corporation, NB Power Transmission Corporation and NB Power Generation Corporation. As part of the Electricity Act, the transmission system reliability, operation and market control functions have been moved into a separate company, the NB System Operator, outside of the NB Power group of companies. A review of Point Lepreau's operational activities will include presentation of the capacity factor, availability and safety results with a summary of significant issues, planned outages and unplanned outages. An update on the current status of Power Reactor Operating License renewal and the strategies for renewal timing will be presented. Planning for refurbishment has continued with a major focus on addressing the recommendations made by Dr. Robin Jeffrey in his report to the Province of New Brunswick. These recommendations included three options for replacement of the Point Lepreau capacity and energy; 1) improve refurbishment contract arrangements with AECL, 2) solicit external investment in refurbishment and the station and 3) update the case for fossil fuel alternatives. The NB Power Holding Corporation Board of Directors have provided the appropriate information on the options to the owner (Province of New Brunswick) for consideration. A decision on the future of the Point Lepreau

Nuclear power plants in Canada: how we address community issues and concerns

International Nuclear Information System (INIS)

McFarlane, D.

2003-01-01

This presentation was developed by the public affairs staff of three Canadian utilities who offered case studies from three nuclear generating stations. Ontario Power Generation (OPG) facilities include Pickering Nuclear, with 8 units, and Darlington Nuclear, with 4 units, both located in the Region of Durham. The Pickering community is located east of Toronto on the shore of Lake Ontario. The facilities are located in the City of Pickering but are close to Ajax and the City of Toronto as well. They are surrounded by residences and businesses. The Darlington station is close to Pickering but further east of Toronto. It is located in a more rural environment in the Municipality of Clarington. Approximately 96% of installed capacity in Quebec is based on hydropower. Hydro-Quebec's Gentilly-2 is the only thermal nuclear generation station in operation. The station is located in Becancour on the south shore of the St. Lawrence River between Quebec City and Montreal. The population of Becancour is 12 000, while Trois-Rivieres and Champlain, on the north shore, count 100 000 residents. New Brunswick Power's Point Lepreau generating station (PLGS) is the only nuclear facility in Atlantic Canada, and supplies some 30% of in-province energy. The station is located in a rural area on the Lepreau peninsula overlooking the Bay of Fundy. It is located within 10 kilometers of the small communities of Dipper Harbour, Maces Bay, Little Lepreau and Chance Harbour. Approximately 38 kilometers to the northeast is located Saint John with a population of about 120 000. Corporate-community relations objectives are similar across the three utilities. They include building trust, garnering support for ongoing operations, and being - as well as being viewed as - a good corporate citizen. Meeting these objectives implies knowing and caring for the community and the issues raised by residents - not just issues of interest to the company. (author)

A distinguishing gravitational property for gravitational equation in higher dimensions

International Nuclear Information System (INIS)

Dadhich, Naresh

2016-01-01

It is well known that Einstein gravity is kinematic (meaning that there is no non-trivial vacuum solution; i.e. the Riemann tensor vanishes whenever the Ricci tensor does so) in 3 dimension because the Riemann tensor is entirely given in terms of the Ricci tensor. Could this property be universalized for all odd dimensions in a generalized theory? The answer is yes, and this property uniquely singles out pure Lovelock (it has only one Nth order term in the action) gravity for which the Nth order Lovelock-Riemann tensor is indeed given in terms of the corresponding Ricci tensor for all odd, d = 2N + 1, dimensions. This feature of gravity is realized only in higher dimensions and it uniquely picks out pure Lovelock gravity from all other generalizations of Einstein gravity. It serves as a good distinguishing and guiding criterion for the gravitational equation in higher dimensions. (orig.)

A distinguishing gravitational property for gravitational equation in higher dimensions

Science.gov (United States)

Dadhich, Naresh

2016-03-01

It is well known that Einstein gravity is kinematic (meaning that there is no non-trivial vacuum solution; i.e. the Riemann tensor vanishes whenever the Ricci tensor does so) in 3 dimension because the Riemann tensor is entirely given in terms of the Ricci tensor. Could this property be universalized for all odd dimensions in a generalized theory? The answer is yes, and this property uniquely singles out pure Lovelock (it has only one Nth order term in the action) gravity for which the Nth order Lovelock-Riemann tensor is indeed given in terms of the corresponding Ricci tensor for all odd, d=2N+1, dimensions. This feature of gravity is realized only in higher dimensions and it uniquely picks out pure Lovelock gravity from all other generalizations of Einstein gravity. It serves as a good distinguishing and guiding criterion for the gravitational equation in higher dimensions.

Rotation curves of galaxies by fourth order gravity

International Nuclear Information System (INIS)

Stabile, A.; Scelza, G.

2011-01-01

We investigate the radial behavior of galactic rotation curves by a Fourth Order Gravity adding also the dark matter component. The Fourth Order Gravity is a theory of gravity described by Lagrangian generalizing the one of Hilbert-Einstein containing a generic function of the Ricci scalar, the Ricci and Riemann tensor. A systematic analysis of rotation curves, in the Newtonian Limit of theory, induced by all galactic substructures of ordinary matter is shown. This analysis is presented for Fourth Order Gravity with and without dark matter. The outcomes are compared with respect to the classical outcomes of General Relativity. The gravitational potential of pointlike mass is the usual potential corrected by two Yukawa terms. The rotation curve is higher or also lower than curve of General Relativity if in the Lagrangian the Ricci scalar square is dominant or not with respect to the contribution of the Ricci tensor square. The theoretical spatial behaviors of rotation curve are compared with the experimental data for the Milky Way and the galaxy NGC 3198. Although the Fourth Order Gravity gives more rotational contributions, in the limit of large distances the Keplerian behavior is ever present, and it is missing only if we add the dark matter component. However by modifying the theory of gravity, consequently, also the spatial description of dark matter could undergo a modification and the free parameters of model can assume different values. After an analytical discussion of theoretical behaviors and the comparing with experimental evidence we can claim that any Fourth Order Gravity is not successful to explain the galactic rotation curves. In the last part of paper we analyze the gravitational potential induced by Lagrangian containing only powers of Ricci scalar. In this case we find an inconsistency in the boundary conditions in the passage from matter to the vacuum.

Weighing Photons Using Bathroom Scales: A Thought Experiment

Science.gov (United States)

Huggins, Elisha

2010-01-01

Jay Orear, in his introductory physics text, defined the weight of a person as the reading one gets when standing on a (properly calibrated) bathroom scale. Here we will use Jay's definition of weight in a thought experiment to measure the weight of a photon. The thought experiment uses the results of the Pound-Rebka-Snider experiments, Compton…

Innovative ultrasonics for power plant commissioning

International Nuclear Information System (INIS)

Murphy, R.V.; Alikhan, S.

1983-05-01

During the commissioning of a nuclear power plant, the usual role of ultrasonics is associated with nondestructive testing of welds. There is, however, a variety of undesirable conditions associated with the fluids carried through the various reactor systems which may be just as important to station operation. A variety of unusual ultrasonic techniques has been developed for testing fluid systems at the Point Lepreau Generating Station. This paper uses the experience gained at the Point Lepreau reactor to illustrate the valuable information which can be gained from these measurements, such as: fluid level in pipes and headers; fluid level in pressure vessels; detection, and sizing of debris in pipes; in situ measurement and verification of orifice condition; detection and location of cavitation, water hammer, valve leakage; quantitative measurement of gate movement within the body of an inservice valve; determination of valve position; detection and imaging of flow separation; detection and location of leaks in concrete containment structures; verification of design flows; balancing of loop flows; and detection of low flow. The application of these techniques at other reactor sites is also discussed

Needle decompositions in Riemannian geometry

CERN Document Server

Klartag, Bo'az

2017-01-01

The localization technique from convex geometry is generalized to the setting of Riemannian manifolds whose Ricci curvature is bounded from below. In a nutshell, the author's method is based on the following observation: When the Ricci curvature is non-negative, log-concave measures are obtained when conditioning the Riemannian volume measure with respect to a geodesic foliation that is orthogonal to the level sets of a Lipschitz function. The Monge mass transfer problem plays an important role in the author's analysis.

Unintended Relevance: The Role of the Stryker Brigade Combat Team in the Decisive Action Environment

Science.gov (United States)

2017-05-25

its_time_to_create_a_megacities_combat_unit_110717.html. 47 Steve Krippel and Chris Ricci, “The Stryker Brigade Combat Team: America’s Early Entry Force,” Infantry, July...vehicles to transport the large amounts of equipment to do their job , which is to fight dismounted in complex terrain. Light infantry is necessary...2015_National_Military_Strategy.pdf. Krippel, Steve , and Chris Ricci. “The Stryker Brigade Combat Team: America’s Early Entry Force.” Infantry, July-September 2014

On butterfly effect in higher derivative gravities

Energy Technology Data Exchange (ETDEWEB)

Alishahiha, Mohsen [School of Physics, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Davody, Ali; Naseh, Ali; Taghavi, Seyed Farid [School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

2016-11-07

We study butterfly effect in D-dimensional gravitational theories containing terms quadratic in Ricci scalar and Ricci tensor. One observes that due to higher order derivatives in the corresponding equations of motion there are two butterfly velocities. The velocities are determined by the dimension of operators whose sources are provided by the metric. The three dimensional TMG model is also studied where we get two butterfly velocities at generic point of the moduli space of parameters. At critical point two velocities coincide.

On butterfly effect in higher derivative gravities

International Nuclear Information System (INIS)

Alishahiha, Mohsen; Davody, Ali; Naseh, Ali; Taghavi, Seyed Farid

2016-01-01

We study butterfly effect in D-dimensional gravitational theories containing terms quadratic in Ricci scalar and Ricci tensor. One observes that due to higher order derivatives in the corresponding equations of motion there are two butterfly velocities. The velocities are determined by the dimension of operators whose sources are provided by the metric. The three dimensional TMG model is also studied where we get two butterfly velocities at generic point of the moduli space of parameters. At critical point two velocities coincide.

The stability of vacuum solutions in generalised gravity

Energy Technology Data Exchange (ETDEWEB)

Madsen, M.S. (Sussex Univ., Brighton (UK). Astronomy Centre); Low, R.J. (Coventry (Lanchester) Polytechnic (UK). Dept. of Mathematics)

1990-05-10

The stability of the Ricci-flat solutions of a large class of generalised gravity theories is examined. It is shown by use of complementary methods that all such solutions are stable in a given theory if that theory admits a truncation to a quadratic theory in which the solution is stable. In particular, this means that the exterior Schwarzschild solution is stable in any gravity theory constructed purely from the Ricci scalar, provided that it exists in that theory. (orig.).

The stability of vacuum solutions in generalised gravity

International Nuclear Information System (INIS)

Madsen, M.S.; Low, R.J.

1990-01-01

The stability of the Ricci-flat solutions of a large class of generalised gravity theories is examined. It is shown by use of complementary methods that all such solutions are stable in a given theory if that theory admits a truncation to a quadratic theory in which the solution is stable. In particular, this means that the exterior Schwarzschild solution is stable in any gravity theory constructed purely from the Ricci scalar, provided that it exists in that theory. (orig.)

Action growth for black holes in modified gravity

Science.gov (United States)

Sebastiani, Lorenzo; Vanzo, Luciano; Zerbini, Sergio

2018-02-01

The general form of the action growth for a large class of static black hole solutions in modified gravity which includes F (R ) -gravity models is computed. The cases of black hole solutions with nonconstant Ricci scalar are also considered, generalizing the results previously found and valid only for black holes with constant Ricci scalar. An argument is put forward to provide a physical interpretation of the results, which seem tightly connected with the generalized second law of black hole thermodynamics.

On some classes of super quasi-Einstein manifolds

International Nuclear Information System (INIS)

Ozguer, Cihan

2009-01-01

Quasi-Einstein and generalized quasi-Einstein manifolds are the generalizations of Einstein manifolds. In this study, we consider a super quasi-Einstein manifold, which is another generalization of an Einstein manifold. We find the curvature characterizations of a Ricci-pseudosymmetric and a quasi-conformally flat super quasi-Einstein manifolds. We also consider the condition C ∼ .S=0 on a super quasi-Einstein manifold, where C ∼ and S denote the quasi-conformal curvature tensor and Ricci tensor of the manifold, respectively.

Torsion in extra-dimensions

International Nuclear Information System (INIS)

Wali, Kameshwar C

2010-01-01

We consider a variant of the 5 dimensional Kaluza-Klein theory within the framework of Einstein-Cartan formalism. By imposing a set of constraints on torsion and Ricci rotation coefficients, we show that the torsion components are completely expressed in terms of the metric. and the Ricci tensor in 5D corresponds exactly to what one would obtain from torsion-free general relativity on a 4D hypersurface. The contributions of the scalar and vector fields of the standard K-K theory to the Ricci tensor and the affine connections are completely nullified by the contributions from the torsion. As a consequence, geodesic motions do not distinguish the torsion free 4D space-time from a hypersurface of 5D space-time with torsion satisfying the constraints. Since torsion is not an independent dynamical variable in this formalism, the modified Einstein equations are different from those in the general Einstein-Cartan theory. This leads to important cosmological consequences such as the emergence of cosmic acceleration.

Annual report, 1979

International Nuclear Information System (INIS)

1979-06-01

In fiscal 1979 efforts continued to be made to reduce New Brunswick's dependance on imported oil. Construction of the Point Lepreau nuclear generating station was slowed by a 64-day strike, but by the end of the year the major portion of the civil engineering work on the project had been finished and work was concentrating on mechanical ad electrical installations. (LL)

Skandinaavia disainis seigeldes / Jay Aspen

Index Scriptorium Estoniae

Aspen, Jay

2008-01-01

Rootsi uue disaini hulgi- ja jaemüüja Michael Asplundi korter Stocholmis Södermalmi linnaosas 1930-ndate keskel ehitatud majas. Tubades on palju disainerite, eriti rootsi disainerite loodud esemeid. Lk. 44: Kristjan Arunurm "Põhjamaine selgus" - valik esemeid kodu sisustamiseks samas võtmes

Seeing Jay-Z in Taipei.

Science.gov (United States)

Hsu, Hua

2011-01-01

How does the newly arrived immigrant respond to the news that an identity already awaits him? How does an African American hip-hop artist translate his struggles and triumphs across oceanic divides? What significance do American demographic shifts have in a global context? Hsu's essay examines what happens once individuals or identities migrate beyond the contexts that first produced them. He explores a variety of circuits: the satellite communities of Asian immigrant students who arrived on American university campuses in the late 1960s; enduring debates about a "post-city" identity, spurred by advances in cheap, efficient, world-shrinking communication technologies; and the new affinities and categories of self-identification made possible by a present-day culture that prizes interactivity and participation.

Dirac equation for massive neutrinos in a Schwarzschild-de Sitter spacetime from a 5D vacuum

International Nuclear Information System (INIS)

Sánchez, Pablo Alejandro; Anabitarte, Mariano; Bellini, Mauricio

2011-01-01

Starting from a Dirac equation for massless neutrino in a 5D Ricci-flat background metric, we obtain the effective 4D equation for massive neutrino in a Schwarzschild-de Sitter (SdS) background metric from an extended SdS 5D Ricci-flat metric. We use the fact that the spin connection is defined to an accuracy of a vector, so that the covariant derivative of the spinor field is strongly dependent of the background geometry. We show that the mass of the neutrino can be induced from the extra space-like dimension.

Higher dimensional maximally symmetric stationary manifold with pure gauge condition and codimension one flat submanifold

International Nuclear Information System (INIS)

Wiliardy, Abednego; Gunara, Bobby Eka

2016-01-01

An n dimensional flat manifold N is embedded into an n +1 dimensional stationary manifold M. The metric of M is derived from a general form of stationary manifold. By taking several assumption, such as 1) the ambient manifold M to be maximally symmetric space and satisfying a pure gauge condition, and 2) the submanifold is taken to be flat, then we find the solution that satisfies Ricci scalar of N . Moreover, we determine whether the solution is compatible with the Ricci and Riemann tensor of manifold N depending on the dimension. (paper)

Properties of kinematic singularities

Energy Technology Data Exchange (ETDEWEB)

Coley, A A [Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia B3H 3J5 (Canada); Hervik, S [Department of Mathematics and Natural Sciences, University of Stavanger, N-4036 Stavanger (Norway); Lim, W C [Albert-Einstein-Institut, Am Muehlenberg 1, D-14476 Potsdam (Germany); MacCallum, M A H, E-mail: aac@mathstat.dal.c, E-mail: sigbjorn.hervik@uis.n, E-mail: wclim@aei.mpg.d, E-mail: m.a.h.maccallum@qmul.ac.u [School of Mathematical Sciences, Queen Mary University of London, E1 4NS (United Kingdom)

2009-11-07

The locally rotationally symmetric tilted perfect fluid Bianchi type V cosmological model provides examples of future geodesically complete spacetimes that admit a 'kinematic singularity' at which the fluid congruence is inextendible but all frame components of the Weyl and Ricci tensors remain bounded. We show that for any positive integer n there are examples of Bianchi type V spacetimes admitting a kinematic singularity such that the covariant derivatives of the Weyl and Ricci tensors up to the nth order also stay bounded. We briefly discuss singularities in classical spacetimes.

General classification of a normally flat Ric- semi symmetric submanifolds

International Nuclear Information System (INIS)

Mirzoyan, V.A.

2012-01-01

It has been proved that a normally flat submanifold M in Euclidean space En satisfies the condition R(X,Y)Ricci =0 if and only if it is the open part of one of the following submanifolds: (1) normally flat two-dimensional submanifold, (2) normally flat Einstein submanifold (in particular Ricci-flat or locally Euclidean), (3) normally flat semi- Einstein submanifold, (4) normally flat interlacing product of semi-Einstein submanifolds and locally Euclidean submanifold (may be of zero dimension), (5) direct product of the above enumerated classes of submanifolds

Killing vector fields in three dimensions: a method to solve massive gravity field equations

Energy Technology Data Exchange (ETDEWEB)

Guerses, Metin, E-mail: gurses@fen.bilkent.edu.t [Department of Mathematics, Faculty of Sciences, Bilkent University, 06800 Ankara (Turkey)

2010-10-21

Killing vector fields in three dimensions play an important role in the construction of the related spacetime geometry. In this work we show that when a three-dimensional geometry admits a Killing vector field then the Ricci tensor of the geometry is determined in terms of the Killing vector field and its scalars. In this way we can generate all products and covariant derivatives at any order of the Ricci tensor. Using this property we give ways to solve the field equations of topologically massive gravity (TMG) and new massive gravity (NMG) introduced recently. In particular when the scalars of the Killing vector field (timelike, spacelike and null cases) are constants then all three-dimensional symmetric tensors of the geometry, the Ricci and Einstein tensors, their covariant derivatives at all orders, and their products of all orders are completely determined by the Killing vector field and the metric. Hence, the corresponding three-dimensional metrics are strong candidates for solving all higher derivative gravitational field equations in three dimensions.

Lawfare: A Current Threat or Much Ado About Nothing?

Science.gov (United States)

2013-04-01

lawyers in the George W. Bush administration such as Jay Bybee , John Yoo and Alberto Gonzales, who viewed the use of legal process as an unlawful tactic...sections 2340, 2340A. 59 Goldsmith, The Terror Presidency, 142. 60 Memorandum from Jay S. Bybee , Assistant Attorney General, to White House...Terror Presidency, 142. 63 Bybee memorandum, 174. 64 Id., 207. 65 Michael J. Lebowitz The Value Of Claiming Torture: An Analysis Of Al Qaeda’s Tactical

Inquiries and technological assessment

International Nuclear Information System (INIS)

1981-01-01

The authors examine six Canadian inquiries to determine their values as scientific assessments, their ability to combine scientific data with policy considerations, and their effectiveness in extending public debate on scientific issues. Among the inquiries examined are the environmental assessment hearings into the Point Lepreau nuclear generating station, the Bayda inquiry into the Cluff Lake uranium mine, and the Porter commission on electric power planning in Ontario

Point Lepreau G.S. commissioning management experience

International Nuclear Information System (INIS)

Alikhan, S.; Walker, W.J.

1983-05-01

This paper shares the experience gained by New Brunswick Power in commissioning its first nuclear plant, with particular emphasis on the management techniques that were developed. Some of the areas discussed include: organization of Nuclear Operations Group responsible for commissioning and its interface with construction; outline and scope of documentation required to define, execute and report commissioning to satisfy the licensing requirements, management techniques developed to implement commissioning; and a summary of lessons learned and recommendations for the future

Palatini approach to Born-Infeld-Einstein theory and a geometric description of electrodynamics

International Nuclear Information System (INIS)

Vollick, Dan N.

2004-01-01

The field equations associated with the Born-Infeld-Einstein action are derived using the Palatini variational technique. In this approach the metric and connection are varied independently and the Ricci tensor is generally not symmetric. For sufficiently small curvatures the resulting field equations can be divided into two sets. One set, involving the antisymmetric part of the Ricci tensor R or μν , consists of the field equation for a massive vector field. The other set consists of the Einstein field equations with an energy momentum tensor for the vector field plus additional corrections. In a vacuum with R or μν =0 the field equations are shown to be the usual Einstein vacuum equations. This extends the universality of the vacuum Einstein equations, discussed by Ferraris et al., to the Born-Infeld-Einstein action. In the simplest version of the theory there is a single coupling constant and by requiring that the Einstein field equations hold to a good approximation in neutron stars it is shown that mass of the vector field exceeds the lower bound on the mass of the photon. Thus, in this case the vector field cannot represent the electromagnetic field and would describe a new geometrical field. In a more general version in which the symmetric and antisymmetric parts of the Ricci tensor have different coupling constants it is possible to satisfy all of the observational constraints if the antisymmetric coupling is much larger than the symmetric coupling. In this case the antisymmetric part of the Ricci tensor can describe the electromagnetic field

Bakry–Émery black holes

International Nuclear Information System (INIS)

Rupert, M; Woolgar, E

2014-01-01

Scalar–tensor gravitation theories, such as the Brans–Dicke family of theories, are commonly partly described by a modified Einstein equation in which the Ricci tensor is replaced by the Bakry–Émery–Ricci tensor of a Lorentzian metric and scalar field. In physics this formulation is sometimes referred to as the ‘Jordan frame’. Just as, in General Relativity, natural energy conditions on the stress–energy tensor become conditions on the Ricci tensor, in scalar–tensor theories expressed in the Jordan frame natural energy conditions become conditions on the Bakry–Émery–Ricci tensor. We show that, if the Bakry–Émery tensor obeys the null energy condition with an upper bound on the Bakry–Émery scalar function, there is a modified notion of apparent horizon which obeys analogues of familiar theorems from General Relativity. The Bakry–Émery modified apparent horizon always lies behind an event horizon and the event horizon obeys a modified area theorem. Under more restrictive conditions, the modified apparent horizon obeys an analogue of the Hawking topology theorem in four spacetime dimensions. Since topological censorship is known to yield a horizon topology theorem independent of the Hawking theorem, in an appendix we obtain a Bakry–Émery version of the topological censorship theorem. We apply our results to the Brans–Dicke theory, and obtain an area theorem for horizons in that theory. Our theorems can be used to understand behaviour observed in numerical simulations by Scheel et al (1995 Phys. Rev. D 51 4236–49) of dust collapse in Brans–Dicke theory. (paper)

Regular reduction of relativistic theories of gravitation with a quadratic Lagrangian

International Nuclear Information System (INIS)

Bel, L.; Zia, H.S.

1985-01-01

We consider those relativistic theories of gravitation which generalize Einstein's theory in the sense that their field equations derive from a scalar Lagrangian which, besides the matter term, contains a linear combination of the Ricci scalar, its square, and the square of the Ricci tensor. Using a generalization of a technique which has been used to deal with some dynamical systems, we regularly and covariantly reduce the corresponding fourth-order differential equations to second-order ones. We examine, in particular, at a low order of approximation, these reduced equations in cosmology, and for static and spherically symmetric interior solutions with constant density

Oak habitat recovery on California's largest islands: Scenarios for the role of corvid seed dispersal

Science.gov (United States)

Pesendorfer, Mario B.; Baker, Christopher M.; Stringer, Martin; McDonald-Madden, Eve; Bode, Michael; McEachern, A. Kathryn; Morrison, Scott A.; Sillett, T. Scott

2018-01-01

Seed dispersal by birds is central to the passive restoration of many tree communities. Reintroduction of extinct seed dispersers can therefore restore degraded forests and woodlands. To test this, we constructed a spatially explicit simulation model, parameterized with field data, to consider the effect of different seed dispersal scenarios on the extent of oak populations. We applied the model to two islands in California's Channel Islands National Park (USA), one of which has lost a key seed disperser.We used an ensemble modelling approach to simulate island scrub oak (Quercus pacifica) demography. The model was developed and trained to recreate known population changes over a 20-year period on 250-km2 Santa Cruz Island, and incorporated acorn dispersal by island scrub-jays (Aphelocoma insularis), deer mice (Peromyscus maniculatus) and gravity, as well as seed predation. We applied the trained model to 215-km2 Santa Rosa Island to examine how reintroducing island scrub-jays would affect the rate and pattern of oak population expansion. Oak habitat on Santa Rosa Island has been greatly reduced from its historical extent due to past grazing by introduced ungulates, the last of which were removed by 2011.Our simulation model predicts that a seed dispersal scenario including island scrub-jays would increase the extent of the island scrub oak population on Santa Rosa Island by 281% over 100 years, and by 544% over 200 years. Scenarios without jays would result in little expansion. Simulated long-distance seed dispersal by jays also facilitates establishment of discontinuous patches of oaks, and increases their elevational distribution.Synthesis and applications. Scenario planning provides powerful decision support for conservation managers. We used ensemble modelling of plant demographic and seed dispersal processes to investigate whether the reintroduction of seed dispersers could provide cost-effective means of achieving broader ecosystem restoration goals on

The ’Torture Memos’: A Failure of Strategic Leadership

Science.gov (United States)

2009-05-11

were issued in August 2002, both signed by Yoo’s superior, Assistant Attorney General (and OLC chief) Jay Bybee . 16 The first memo, addressed to...investigation into the professional responsibility of Yoo, Bybee , and another OLC attorney, underway for nearly 5 years, was completed in 2008 but has...Office of Legal Counsel, Jay S. Bybee , “Re: Standards of Conduct for Interrogation under 18 U.S.C. §§2340-2340A," memorandum for Alberto R. 23 Gonzales

Preference for oddity: uniqueness heuristic or hierarchical choice process?

Science.gov (United States)

Waite, Thomas A

2008-10-01

Traditional economic theories assume decision makers in multialternative choice tasks "assign" a value to each option and then express rational preferences. Here, I report an apparent violation of such rationality in gray jays (Perisoreus canadensis). I tested the jays' preference in a quaternary choice task where three options were the same color and the fourth option was a different color. All options offered an identical food reward and so the strictly rational expectation was that subjects would choose the odd-colored option in 25% of choices. In clear disagreement, every subject chose the odd option more frequently than expected. I speculate as to how this surprising preference for oddity might have been ecologically rational: by using a unique-choice heuristic, the jays might have been able to bypass a deliberative phase of the decision process and devote more attention to scanning for predators. Alternatively, it is conceivable that the jays did not prefer oddity per se. Instead, they might have used a hierarchical process, assigning options to color categories and then choosing between categories. If so, their behavior matches expectation after all (on average, subjects chose the odd option 50% of the time). It should be straightforward to test these competing hypotheses. The current results can be viewed as a new example of how simple mechanisms sometimes produce economically puzzling yet ecologically rational decision making.

1978 annual report

International Nuclear Information System (INIS)

1978-06-01

In fiscal 1978 efforts continued to be made to increase New Brunswick's energy independence through research into and development of indigenous power sources including coal, peat, tidal, and hydroelectric resources. At Point Lepreau nuclear generating station the reactor building was completed, the concrete vault was prepared, and the calandria was installed. Work continued within the reactor building. Excavation of the cooling water tunnels and riser shafts was completed. (LL)

Elements of episodic-like memory in animals.

OpenAIRE

Clayton, N S; Griffiths, D P; Emery, N J; Dickinson, A

2001-01-01

A number of psychologists have suggested that episodic memory is a uniquely human phenomenon and, until recently, there was little evidence that animals could recall a unique past experience and respond appropriately. Experiments on food-caching memory in scrub jays question this assumption. On the basis of a single caching episode, scrub jays can remember when and where they cached a variety of foods that differ in the rate at which they degrade, in a way that is inexplicable by relative fam...

A Vibration-Based Approach for Stator Winding Fault Diagnosis of Induction Motors: Application of Envelope Analysis

Science.gov (United States)

2014-10-02

through a low-pass and an anti-aliasing filter embedded in each channel of the NI data acquisition system . Doing the tests in this way ensures that the...Ompusunggu 2 , Zongchang Liu 1 , Hossein D. Ardakani 1 , Fredrik Petré 2 , and Jay Lee 1 1 NSF I/UCRC Center for Intelligent Maintenance Systems (IMS...Cincinnati, OH, 45221,USA jinco@mail.uc.edu liuzc@mail.uc.edu davarihn@mail.uc.edu jay.lee@uc.edu 2 Flanders’ Mechatronics Technology Centre (FMTC

A Rotational and Axial Motion System Load Frame Insert for In Situ High Energy X-Ray Studies (Postprint)

Science.gov (United States)

2015-09-08

Paul A. Shade, Jay C. Schuren, and Todd J. Turner AFRL/RX Basil Blank PulseRay Peter Kenesei, Kurt Goetze, Ulrich Lienert, and Jonathan Almer...AFRL/RX 2) Basil Blank – PulseRay (continued on page 2) 5d. PROJECT NUMBER 4349 5e. TASK NUMBER 0001 5f...2015) A rotational and axial motion system load frame insert for in situ high energy x-ray studies Paul A. Shade,1,a) Basil Blank,2 Jay C. Schuren,1,b

Paint Removal from Composites and Protective Coating Development

Science.gov (United States)

1991-01-01

WL-TR-91-4025 AD-A249 238 PAINT REMOVAL FROM COMPOSITES AND PROTECTIVE COATING DEVELOPMENT Peter W. Kopf Jay Cheney John Martin, et al. Arthur D...PERSONAL AUTHOR(S) Peter Kopf, Jay Cheney, John Martin et al. 13a TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Year, Mot, Day) I1S. PAGE COUNT...Adhesive -.............. "𔃺*/900 -.... .... .... -- - 450 - - - -------- - -- e nk~ T17 J 50 ,1 ZEC 9837 Experimental 350OF Surfacing Film DESCRIPTION XHC

Differential geometry of groups in string theory

International Nuclear Information System (INIS)

Schmidke, W.B. Jr.

1990-09-01

Techniques from differential geometry and group theory are applied to two topics from string theory. The first topic studied is quantum groups, with the example of GL (1|1). The quantum group GL q (1|1) is introduced, and an exponential description is derived. The algebra and coproduct are determined using the invariant differential calculus method introduced by Woronowicz and generalized by Wess and Zumino. An invariant calculus is also introduced on the quantum superplane, and a representation of the algebra of GL q (1|1) in terms of the super-plane coordinates is constructed. The second topic follows the approach to string theory introduced by Bowick and Rajeev. Here the ghost contribution to the anomaly of the energy-momentum tensor is calculated as the Ricci curvature of the Kaehler quotient space Diff(S 1 )/S 1 . We discuss general Kaehler quotient spaces and derive an expression for their Ricci curvatures. Application is made to the string and superstring diffeomorphism groups, considering all possible choices of subgroup. The formalism is extended to associated holomorphic vector bundles, where the Ricci curvature corresponds to the anomaly for different ghost sea levels. 26 refs

Simple cosmological model with inflation and late times acceleration

Science.gov (United States)

Szydłowski, Marek; Stachowski, Aleksander

2018-03-01

In the framework of polynomial Palatini cosmology, we investigate a simple cosmological homogeneous and isotropic model with matter in the Einstein frame. We show that in this model during cosmic evolution, early inflation appears and the accelerating phase of the expansion for the late times. In this frame we obtain the Friedmann equation with matter and dark energy in the form of a scalar field with a potential whose form is determined in a covariant way by the Ricci scalar of the FRW metric. The energy density of matter and dark energy are also parameterized through the Ricci scalar. Early inflation is obtained only for an infinitesimally small fraction of energy density of matter. Between the matter and dark energy, there exists an interaction because the dark energy is decaying. For the characterization of inflation we calculate the slow roll parameters and the constant roll parameter in terms of the Ricci scalar. We have found a characteristic behavior of the time dependence of density of dark energy on the cosmic time following the logistic-like curve which interpolates two almost constant value phases. From the required numbers of N-folds we have found a bound on the model parameter.

Energy functionals for Calabi-Yau metrics

International Nuclear Information System (INIS)

Headrick, M; Nassar, A

2013-01-01

We identify a set of ''energy'' functionals on the space of metrics in a given Kähler class on a Calabi-Yau manifold, which are bounded below and minimized uniquely on the Ricci-flat metric in that class. Using these functionals, we recast the problem of numerically solving the Einstein equation as an optimization problem. We apply this strategy, using the ''algebraic'' metrics (metrics for which the Kähler potential is given in terms of a polynomial in the projective coordinates), to the Fermat quartic and to a one-parameter family of quintics that includes the Fermat and conifold quintics. We show that this method yields approximations to the Ricci-flat metric that are exponentially accurate in the degree of the polynomial (except at the conifold point, where the convergence is polynomial), and therefore orders of magnitude more accurate than the balanced metrics, previously studied as approximations to the Ricci-flat metric. The method is relatively fast and easy to implement. On the theoretical side, we also show that the functionals can be used to give a heuristic proof of Yau's theorem

Gauges and functional measures in quantum gravity II: higher-derivative gravity

Energy Technology Data Exchange (ETDEWEB)

Ohta, N. [Kindai University, Department of Physics, Higashi-Osaka, Osaka (Japan); Percacci, R. [International School for Advanced Studies, Trieste (Italy); INFN, Sezione di Trieste, Trieste (Italy); Pereira, A.D. [UERJ-Universidade do Estado do Rio de Janeiro, Departamento de Fisica Teorica, Rio de Janeiro (Brazil)

2017-09-15

We compute the one-loop divergences in a higher-derivative theory of gravity including Ricci tensor squared and Ricci scalar squared terms, in addition to the Hilbert and cosmological terms, on an (generally off-shell) Einstein background. We work with a two-parameter family of parametrizations of the graviton field, and a two-parameter family of gauges. We find that there are some choices of gauge or parametrization that reduce the dependence on the remaining parameters. The results are invariant under a recently discovered ''duality'' that involves the replacement of the densitized metric by a densitized inverse metric as the fundamental quantum variable. (orig.)

Gradient estimates on the weighted p-Laplace heat equation

Science.gov (United States)

Wang, Lin Feng

2018-01-01

In this paper, by a regularization process we derive new gradient estimates for positive solutions to the weighted p-Laplace heat equation when the m-Bakry-Émery curvature is bounded from below by -K for some constant K ≥ 0. When the potential function is constant, which reduce to the gradient estimate established by Ni and Kotschwar for positive solutions to the p-Laplace heat equation on closed manifolds with nonnegative Ricci curvature if K ↘ 0, and reduce to the Davies, Hamilton and Li-Xu's gradient estimates for positive solutions to the heat equation on closed manifolds with Ricci curvature bounded from below if p = 2.

Stability of the effective potential of the gauge-less top-Higgs model in curved spacetime

Energy Technology Data Exchange (ETDEWEB)

Czerwińska, Olga; Lalak, Zygmunt; Nakonieczny, Łukasz [Institute of Theoretical Physics, Faculty of Physics, University of Warsaw,ul. Pasteura 5, 02-093 Warszawa (Poland)

2015-11-30

We investigate stability of the Higgs effective potential in curved spacetime. To this end, we consider the gauge-less top-Higgs sector with an additional scalar field. Explicit form of the terms proportional to the squares of the Ricci scalar, the Ricci tensor and the Riemann tensor that arise at the one-loop level in the effective action has been determined. We have investigated the influence of these terms on the stability of the scalar effective potential. The result depends on background geometry. In general, the potential becomes modified both in the region of the electroweak minimum and in the region of large field strength.

Evaluation of the nasolabial angle in the Indian population

Science.gov (United States)

Dua, Vinay; Gupta, Shilpa; Singh, Chanjyot

2010-01-01

Nasolabial angle has become the angle depicting the esthetics so has attained the prime importance in the treatment planning. Dr Jay P. Fitzgerland and Dr. Ram S. Nanda. In 1992 gave norms for Caucasian population. A radiographic cephalometric study was undertaken with 45 subjects of Indian origin to evaluate and compare with their result. The method of evaluation was according to the criteria given by Dr. Jay P Fitzergerald in AJODO 1992; 102:328-34. Significant decrease in nasolabial angle values was found in case of Indian population as compared to white adults. PMID:22114388

Dynamics of Turbulence Suppression in a Helicon Plasma

Science.gov (United States)

Hayes, Tiffany; Gilmore, Mark

2012-10-01

Experiments are currently being conducted in the the Helicon-Cathode Device (HelCat) at the University of New Mexico. The goal is to the study in detail the transition from a turbulent to a non-turbulent state in the presence of flow shear. HelCat has intrinsic fluctuations that have been identified as drift-waves. Using simple electrode biasing, it has been found that these fluctuations can be completely suppressed. In some extreme cases, a different instability, possibly the Kelvin-Helmholtz instability, can be excited. Detailed studies are underway in order to understand the characteristics of each mode, and to elucidate the underlying physics that cause the change between an unstable plasma, and an instability-free plasma. Dynamics being observed include changes in flow profiles, both azimuthal and parallel, as well as changes in potential and temperature gradients. Further understanding is being sought using several computer codes developed at EPFL: a linear stability solver (LSS,footnotetextP. Ricci and B.N. Rogers (2009). Phys Plasmas 16, 062303. a one-dimensional PIC code/sheath solver, ODISEE,footnotetextJ. Loizu, P. Ricci, and C. Theiler (2011). Phys Rev E 83, 016406 and a global, 3D Braginski code, GBS.footnotetextRicci, Rogers (2009) A basic overview of results will be presented.

Evaluation of the nasolabial angle in the Indian population

Directory of Open Access Journals (Sweden)

Vinay Dua

2010-01-01

Full Text Available Nasolabial angle has become the angle depicting the esthetics so has attained the prime importance in the treatment planning. Dr Jay P. Fitzgerland and Dr. Ram S. Nanda. In 1992 gave norms for Caucasian population. A radiographic cephalometric study was undertaken with 45 subjects of Indian origin to evaluate and compare with their result. The method of evaluation was according to the criteria given by Dr. Jay P Fitzergerald in AJODO 1992; 102:328-34. Significant decrease in nasolabial angle values was found in case of Indian population as compared to white adults.

A perturbative solution for gravitational waves in quadratic gravity

International Nuclear Information System (INIS)

Neto, Edgard C de Rey; Aguiar, Odylio D; Araujo, Jose C N de

2003-01-01

We find a gravitational wave solution to the linearized version of quadratic gravity by adding successive perturbations to Einstein's linearized field equations. We show that only the Ricci-squared quadratic invariant contributes to give a different solution to those found in Einstein's general relativity. The perturbative solution is written as a power series in the β parameter, the coefficient of the Ricci-squared term in the quadratic gravitational action. We also show that, for monochromatic waves of a given angular frequency ω, the perturbative solution can be summed out to give an exact solution to the linearized version of quadratic gravity, for 0 1/2 . This result may lead to implications for the predictions for gravitational wave backgrounds of cosmological origin

Recent developments in Canadian nuclear power plant licensing practices

International Nuclear Information System (INIS)

Marchildon, P.

1985-06-01

This paper examines the dominant factors which have influenced the safety evaluation and licensing process of current 600 MW reactors. It describes possible modifications to the process which are being considered for the licensing of a second 600 MW reactor at Point Lepreau. The key element is a firm licensing agreement covering the entire licensing cycle, to be established between the proponent and the AECB before a construction licence is issued. Progress accomplished to date in reaching such an agreement is described

Management of a 600 MW CANDU project to facilitate electricity export

International Nuclear Information System (INIS)

Gunter, G.E.

1983-06-01

The export of electricity from 600-MW CANDU nuclear power plants built in Canada remains feasible providing certain requirements continue to be met. The principal objective in developing nuclear power resources for export is that they must produce economically attractive electricity. A review of the experience of construction and operation of Point Lepreau Unit 1 suggests an inherent ability to reduce construction costs and shorten construction schedules so as to make electrical power output from these stations even more attractive to export customers

Selection of equipment for equipment qualification

International Nuclear Information System (INIS)

Torr, K.G.

1989-01-01

This report describes the methodology applied in selecting equipment in the special safety systems for equipment qualification in the CANDU 600 MW nuclear generating stations at Gentilly 2 and Point Lepreau. Included is an explanation of the selection procedure adopted and the rationale behind the criteria used in identifying the equipment. The equipment items on the list have been grouped into three priority categories as a planning aid to AECB staff for a review of the qualification status of the special safety systems

Coaching for improved personal and organizational effectiveness

International Nuclear Information System (INIS)

Miller, K.; Williams, R.A.

2002-01-01

Leadership ability and highly developed interpersonal skills are essential for both organizational and personal effectiveness. High-performance organizations have typically taken an integrated approach to address these critical needs. One element of a comprehensive strategy to improve these key competencies is to provide both individual and work-group coaching. This paper describes what leaders at the Pt. Lepreau NGS have experienced while receiving personal and small group coaching, and the effect it has had on their overall performance effectiveness. (author)

Coaching for improved personal and organizational effectiveness

Energy Technology Data Exchange (ETDEWEB)

Miller, K. [Point Lepreau Nuclear Generating Station, Lepreau, New Brunswick (Canada); Williams, R.A. [Briant-Williams, (Canada)

2002-07-01

Leadership ability and highly developed interpersonal skills are essential for both organizational and personal effectiveness. High-performance organizations have typically taken an integrated approach to address these critical needs. One element of a comprehensive strategy to improve these key competencies is to provide both individual and work-group coaching. This paper describes what leaders at the Pt. Lepreau NGS have experienced while receiving personal and small group coaching, and the effect it has had on their overall performance effectiveness. (author)

Empirical pKb and pKa for Nonmetal Hydrides from Periodic Table Position.

Science.gov (United States)

Bayless, Philip L.

1983-01-01

Provides and discusses an equation which, when combined with the well-known Ricci equation for oxyacids, results in a generally useful equation for dealing with acid dissociation experiments and analyses. (JN)

Covariant energy–momentum and an uncertainty principle for general relativity

Energy Technology Data Exchange (ETDEWEB)

Cooperstock, F.I., E-mail: cooperst@uvic.ca [Department of Physics and Astronomy, University of Victoria, P.O. Box 3055, Victoria, B.C. V8W 3P6 (Canada); Dupre, M.J., E-mail: mdupre@tulane.edu [Department of Mathematics, Tulane University, New Orleans, LA 70118 (United States)

2013-12-15

We introduce a naturally-defined totally invariant spacetime energy expression for general relativity incorporating the contribution from gravity. The extension links seamlessly to the action integral for the gravitational field. The demand that the general expression for arbitrary systems reduces to the Tolman integral in the case of stationary bounded distributions, leads to the matter-localized Ricci integral for energy–momentum in support of the energy localization hypothesis. The role of the observer is addressed and as an extension of the special relativistic case, the field of observers comoving with the matter is seen to compute the intrinsic global energy of a system. The new localized energy supports the Bonnor claim that the Szekeres collapsing dust solutions are energy-conserving. It is suggested that in the extreme of strong gravity, the Heisenberg Uncertainty Principle be generalized in terms of spacetime energy–momentum. -- Highlights: •We present a totally invariant spacetime energy expression for general relativity incorporating the contribution from gravity. •Demand for the general expression to reduce to the Tolman integral for stationary systems supports the Ricci integral as energy–momentum. •Localized energy via the Ricci integral is consistent with the energy localization hypothesis. •New localized energy supports the Bonnor claim that the Szekeres collapsing dust solutions are energy-conserving. •Suggest the Heisenberg Uncertainty Principle be generalized in terms of spacetime energy–momentum in strong gravity extreme.

Performance improvement - business excellence processes

International Nuclear Information System (INIS)

Doucett, J.

2010-01-01

This presentation discusses Performance Improvement which is defined as 'the process of identifying and analyzing important organizational and individual performance gaps, planning for future performance improvement, designing and developing cost-effective and ethically justifiable intervention to close performance gaps, implementing the interventions and evaluating the financial and non-financial results', i.e. making things better. Specifically, it discusses the refurbishment outage at the Point Lepreau Power Plant that began at the end of March 2008. The business risks identified in 2008 were leadership, demographics and management system.

On M-theory fourfold vacua with higher curvature terms

International Nuclear Information System (INIS)

Grimm, Thomas W.; Pugh, Tom G.; Weißenbacher, Matthias

2015-01-01

We study solutions to the eleven-dimensional supergravity action, including terms quartic and cubic in the Riemann curvature, that admit an eight-dimensional compact space. The internal background is found to be a conformally Kähler manifold with vanishing first Chern class. The metric solution, however, is non-Ricci-flat even when allowing for a conformal rescaling including the warp factor. This deviation is due to the possible non-harmonicity of the third Chern-form in the leading order Ricci-flat metric. We present a systematic derivation of the background solution by solving the Killing spinor conditions including higher curvature terms. These are translated into first-order differential equations for a globally defined real two-form and complex four-form on the fourfold. We comment on the supersymmetry properties of the described solutions

Rigidity of generalized Bach-flat vacuum static spaces

Science.gov (United States)

Yun, Gabjin; Hwang, Seungsu

2017-11-01

In this paper, we study the structure of generalized Bach-flat vacuum static spaces. Generalized Bach-flat metrics are considered as extensions of both Einstein and Bach-flat metrics. First, we prove that a compact Riemannian n-manifold with n ≥ 4 which is a generalized Bach-flat vacuum static space is Einstein. A generalized Bach-flat vacuum static space with the potential function f having compact level sets is either Ricci-flat or a warped product with zero scalar curvature when n ≥ 5, and when n = 4, it is Einstein if f has its minimum. Secondly, we consider critical metrics for another quadratic curvature functional involving the Ricci tensor, and prove similar results. Lastly, by applying the technique developed above, we prove Besse conjecture when the manifold is generalized Bach-flat.

Non-linear realization of the Virasoro-Kac-Moody algebra and the anomalies

International Nuclear Information System (INIS)

Aoyama, S.

1988-01-01

The non-linear realization of the Virasoro algebra x Kac-Moody algebra will be studied. We will calculate the Ricci tensor of the relevant Kaehler manifold to show a new vacuum structure for this coupled algebra. (orig.)

Rotationally symmetric extremal pseudo-Kähler metrics of non ...

Indian Academy of Sciences (India)

Xiaojuan Duan

XIAOJUAN DUAN. Department of Applied Mathematics, Xiamen University of Technology,. Xiamen 361024, China. E-mail: ... published online 22 March 2018. Abstract. ... of Kähler Ricci-flat metrics that depend on a parameter a. When a → 0+.

Performance improvement - business excellence processes

Energy Technology Data Exchange (ETDEWEB)

Doucett, J. [NB Nuclear Power, Point Lepreau, New Brunswick (Canada)

2010-07-01

This presentation discusses Performance Improvement which is defined as 'the process of identifying and analyzing important organizational and individual performance gaps, planning for future performance improvement, designing and developing cost-effective and ethically justifiable intervention to close performance gaps, implementing the interventions and evaluating the financial and non-financial results', i.e. making things better. Specifically, it discusses the refurbishment outage at the Point Lepreau Power Plant that began at the end of March 2008. The business risks identified in 2008 were leadership, demographics and management system.

The effect of fog on radionuclide deposition velocities

International Nuclear Information System (INIS)

Gibb, R.; Carson, P.; Thompson, W.

1997-01-01

Current nuclear power station release models do not evaluate deposition under foggy atmospheric conditions. Deposition velocities and scavenging coefficients of radioactive particles entrained in fog are presented for the Point Lepreau area of the Bay of Fundy coast. It is recommended to calculate deposition based on fog deposition velocities. The deposition velocities can be calculated from common meteorological data. The range of deposition velocities is approximately 1 - 100 cm/s. Fog deposition is surface roughness dependent with forests having larger deposition and deposition velocities than soil or grasses. (author)

Performance improvement program: goals and experience

International Nuclear Information System (INIS)

Guglielmi, F.

2015-01-01

Following long 54 month refurbishment outage at Point Lepreau Generating Station, operational performance had fallen below industry standards in a number of areas. Leadership development and succession planning had stalled. Operational focus was low primarily due to the construction focus during refurbishment. Condition of balance of plant was poor including several long standing deficiencies. In order to improve performance, the site implemented a framework based on INPO 12-011: Focus on Improving Behaviours; Set common goals and demonstrate results; Align and engage the organization; Drive to achieve high levels of performance and sustain performance.

Year in review: 1993

International Nuclear Information System (INIS)

Reid, J.M.

1994-01-01

This review of the year includes mention of the following subjects: The good performance of CANDU reactors worldwide (especially Point Lepreau and Wolsung-1); Permission granted to proceed with four new uranium projects in Saskatchewan; Failure of a suit brought by Energy Probe, the City of Toronto and Roslie Bertell claiming unconstitutionality of the Nuclear Liability Act; The International Nuclear Congress (INC93) in Toronto, and other conferences; Consultations with the Government of Canada regarding license fees to be charged by the AECB, and also consultations regarding the environment and other matters

Performance improvement program: goals and experience

Energy Technology Data Exchange (ETDEWEB)

Guglielmi, F. [Point Lepreau Generating Station, Maces Bay, New Brunswick (Canada)

2015-07-01

Following long 54 month refurbishment outage at Point Lepreau Generating Station, operational performance had fallen below industry standards in a number of areas. Leadership development and succession planning had stalled. Operational focus was low primarily due to the construction focus during refurbishment. Condition of balance of plant was poor including several long standing deficiencies. In order to improve performance, the site implemented a framework based on INPO 12-011: Focus on Improving Behaviours; Set common goals and demonstrate results; Align and engage the organization; Drive to achieve high levels of performance and sustain performance.

Terrestrial Sagnac delay constraining modified gravity models

Science.gov (United States)

Karimov, R. Kh.; Izmailov, R. N.; Potapov, A. A.; Nandi, K. K.

2018-04-01

Modified gravity theories include f(R)-gravity models that are usually constrained by the cosmological evolutionary scenario. However, it has been recently shown that they can also be constrained by the signatures of accretion disk around constant Ricci curvature Kerr-f(R0) stellar sized black holes. Our aim here is to use another experimental fact, viz., the terrestrial Sagnac delay to constrain the parameters of specific f(R)-gravity prescriptions. We shall assume that a Kerr-f(R0) solution asymptotically describes Earth's weak gravity near its surface. In this spacetime, we shall study oppositely directed light beams from source/observer moving on non-geodesic and geodesic circular trajectories and calculate the time gap, when the beams re-unite. We obtain the exact time gap called Sagnac delay in both cases and expand it to show how the flat space value is corrected by the Ricci curvature, the mass and the spin of the gravitating source. Under the assumption that the magnitude of corrections are of the order of residual uncertainties in the delay measurement, we derive the allowed intervals for Ricci curvature. We conclude that the terrestrial Sagnac delay can be used to constrain the parameters of specific f(R) prescriptions. Despite using the weak field gravity near Earth's surface, it turns out that the model parameter ranges still remain the same as those obtained from the strong field accretion disk phenomenon.

Background field method in gauge theories and on linear sigma models

International Nuclear Information System (INIS)

van de Ven, A.E.M.

1986-01-01

This dissertation constitutes a study of the ultraviolet behavior of gauge theories and two-dimensional nonlinear sigma-models by means of the background field method. After a general introduction in chapter 1, chapter 2 presents algorithms which generate the divergent terms in the effective action at one-loop for arbitrary quantum field theories in flat spacetime of dimension d ≤ 11. It is demonstrated that global N = 1 supersymmetric Yang-Mills theory in six dimensions in one-loop UV-finite. Chapter 3 presents an algorithm which produces the divergent terms in the effective action at two-loops for renormalizable quantum field theories in a curved four-dimensional background spacetime. Chapter 4 presents a study of the two-loop UV-behavior of two-dimensional bosonic and supersymmetric non-linear sigma-models which include a Wess-Zumino-Witten term. It is found that, to this order, supersymmetric models on quasi-Ricci flat spaces are UV-finite and the β-functions for the bosonic model depend only on torsionful curvatures. Chapter 5 summarizes a superspace calculation of the four-loop β-function for two-dimensional N = 1 and N = 2 supersymmetric non-linear sigma-models. It is found that besides the one-loop contribution which vanishes on Ricci-flat spaces, the β-function receives four-loop contributions which do not vanish in the Ricci-flat case. Implications for superstrings are discussed. Chapters 6 and 7 treat the details of these calculations

Dynamics of higher-dimensional FRW cosmology in Rp exp(λR ...

Indian Academy of Sciences (India)

2017-01-04

Jan 4, 2017 ... In these theories, the Hilbert–Einstein action of general relativity (GR) is generalized by replacing the Ricci ... explain the inflationary expansion of the Universe. On the other ... dimensions will in general be different from that.

Recommender Systems in Technology Enhanced Learning

NARCIS (Netherlands)

Manouselis, Nikos; Drachsler, Hendrik; Vuorikari, Riina; Hummel, Hans; Koper, Rob

2010-01-01

Manouselis, N., Drachsler, H., Vuorikari, R., Hummel, H. G. K., & Koper, R. (2011). Recommender Systems in Technology Enhanced Learning. In P. B. Kantor, F. Ricci, L. Rokach, & B. Shapira (Eds.), Recommender Systems Handbook (pp. 387-415). Berlin: Springer.

On Analytical Solutions of f(R) Modified Gravity Theories in FLRW Cosmologies

Science.gov (United States)

Domazet, Silvije; Radovanović, Voja; Simonović, Marko; Štefančić, Hrvoje

2013-02-01

A novel analytical method for f(R) modified theories without matter in Friedmann-Lemaitre-Robertson-Walker (FLRW) spacetimes is introduced. The equation of motion for the scale factor in terms of cosmic time is reduced to the equation for the evolution of the Ricci scalar R with the Hubble parameter H. The solution of equation of motion for actions of the form of power law in Ricci scalar R is presented with a detailed elaboration of the action quadratic in R. The reverse use of the introduced method is exemplified in finding functional forms f(R), which leads to specified scale factor functions. The analytical solutions are corroborated by numerical calculations with excellent agreement. Possible further applications to the phases of inflationary expansion and late-time acceleration as well as f(R) theories with radiation are outlined.

Irreversibility of world-sheet renormalization group flow

International Nuclear Information System (INIS)

Oliynyk, T.; Suneeta, V.; Woolgar, E.

2005-01-01

We demonstrate the irreversibility of a wide class of world-sheet renormalization group (RG) flows to first order in α ' in string theory. Our techniques draw on the mathematics of Ricci flows, adapted to asymptotically flat target manifolds. In the case of somewhere-negative scalar curvature (of the target space), we give a proof by constructing an entropy that increases monotonically along the flow, based on Perelman's Ricci flow entropy. One consequence is the absence of periodic solutions, and we are able to give a second, direct proof of this. If the scalar curvature is everywhere positive, we instead construct a regularized volume to provide an entropy for the flow. Our results are, in a sense, the analogue of Zamolodchikov's c-theorem for world-sheet RG flows on noncompact spacetimes (though our entropy is not the Zamolodchikov C-function)

Elements of episodic-like memory in animals.

Science.gov (United States)

Clayton, N S; Griffiths, D P; Emery, N J; Dickinson, A

2001-09-29

A number of psychologists have suggested that episodic memory is a uniquely human phenomenon and, until recently, there was little evidence that animals could recall a unique past experience and respond appropriately. Experiments on food-caching memory in scrub jays question this assumption. On the basis of a single caching episode, scrub jays can remember when and where they cached a variety of foods that differ in the rate at which they degrade, in a way that is inexplicable by relative familiarity. They can update their memory of the contents of a cache depending on whether or not they have emptied the cache site, and can also remember where another bird has hidden caches, suggesting that they encode rich representations of the caching event. They make temporal generalizations about when perishable items should degrade and also remember the relative time since caching when the same food is cached in distinct sites at different times. These results show that jays form integrated memories for the location, content and time of caching. This memory capability fulfils Tulving's behavioural criteria for episodic memory and is thus termed 'episodic-like'. We suggest that several features of episodic memory may not be unique to humans.

Naive Juveniles Are More Likely to Become Breeders after Witnessing Predator Mobbing.

Science.gov (United States)

Griesser, Michael; Suzuki, Toshitaka N

2017-01-01

Responding appropriately during the first predatory attack in life is often critical for survival. In many social species, naive juveniles acquire this skill from conspecifics, but its fitness consequences remain virtually unknown. Here we experimentally demonstrate how naive juvenile Siberian jays (Perisoreus infaustus) derive a long-term fitness benefit from witnessing knowledgeable adults mobbing their principal predator, the goshawk (Accipiter gentilis). Siberian jays live in family groups of two to six individuals that also can include unrelated nonbreeders. Field observations showed that Siberian jays encounter predators only rarely, and, indeed, naive juveniles do not respond to predator models when on their own but do when observing other individuals mobbing them. Predator exposure experiments demonstrated that naive juveniles had a substantially higher first-winter survival after observing knowledgeable group members mobbing a goshawk model, increasing their likelihood of acquiring a breeding position later in life. Previous research showed that naive individuals may learn from others how to respond to predators, care for offspring, or choose mates, generally assuming that social learning has long-term fitness consequences without empirical evidence. Our results demonstrate a long-term fitness benefit of vertical social learning for naive individuals in the wild, emphasizing its evolutionary importance in animals, including humans.

Time frames: the rethinking of Darwinian evolution and the theory of punctuated equilibria

National Research Council Canada - National Science Library

Eldredge, Niles

1985-01-01

.... Two eminent scientists, Niles Eldredge and Stephen Jay Gould, startled the world by challenging Darwin's cherished beliefs - proposing instead that once a species has evolved it rarely undergoes...

Development of the Young Brain

Medline Plus

Full Text Available ... Training (1 item) Other Treatments (15 items) Alzheimer’s ... twenty years, National Institute of Mental Health neuroscientist Dr. Jay Giedd has studied the development of the ...

Combinatorial differential geometry and ideal Bianchi-Ricci identities

Czech Academy of Sciences Publication Activity Database

Janyška, J.; Markl, Martin

2011-01-01

Roč. 11, č. 3 (2011), s. 509-540 ISSN 1615-715X R&D Projects: GA ČR GA201/08/0397 Institutional research plan: CEZ:AV0Z10190503 Keywords : Natural operator * linear connection * reduction theorem Subject RIV: BA - General Mathematics Impact factor: 0.338, year: 2011 http://www.degruyter.com/view/j/advg.2011.11.issue-3/advgeom.2011.017/advgeom.2011.017. xml

Combinatorial differential geometry and ideal Bianchi-Ricci identities

Czech Academy of Sciences Publication Activity Database

Janyška, J.; Markl, Martin

2011-01-01

Roč. 11, č. 3 (2011), s. 509-540 ISSN 1615-715X R&D Projects: GA ČR GA201/08/0397 Institutional research plan: CEZ:AV0Z10190503 Keywords : Natural operator * linear connection * reduction theorem Subject RIV: BA - General Mathematics Impact factor: 0.338, year: 2011 http://www.degruyter.com/view/j/advg.2011.11.issue-3/advgeom.2011.017/advgeom.2011.017.xml

El Fragmento de Biblia Dericci Ms 5 (Italia, segunda mitad del siglo XIII.

Directory of Open Access Journals (Sweden)

Ramos Rubert, Eulalia

2014-06-01

Full Text Available This research focuses on a group of European manuscripts belonging to NYPL used in the liturgy of the Catholic Church between the Xth and XVth centuries, which form part of the DeRicci Collection. This paper begins with the study of DeRicci ms 5, fragment of an Italian Bible. As an innovation, is studied the biblical content and its influence on the conservation process, in addition to its comparative association with Vat.lat.25, Chig.A.VI.161, Chig.A.VI.162, Bibles belonging to the BAV. A description of the elements of the book, the nature of the material and the crafts involved in its preparation. A detailed study of the technical executive, allowing an assessment of previous conservation works, and the analysis of the state of conservation of the volume. Several considerations and conclusions are deducted for a conservation proposal. Descriptions are provided on the body of the book, the contents of the gatherings, capitals and notes on paper.Investigación de un grupo de manuscritos europeos pertenecientes a la NYPL utilizados para la liturgia de la Iglesia católica entre los siglos X y XV, que actualmente forman parte del DeRicci Collection. Se comienza con el estudio del DeRicci ms 5, fragmento de Biblia italiana. Como novedad, se estudia el contenido bíblico y su influencia en el proceso de restauración, además de su asociación comparativa con Vat.lat.25, Chig.A.VI.161, Chig.A.VI.162, biblias pertenecientes a la BAV. Descripción de los elementos constitutivos del libro, naturaleza de sus materiales y oficios artesanales que intervienen en su elaboración. Estudio detallado sobre la técnica ejecutiva, valoración de las intervenciones precedentes, y análisis del estado de conservación del volumen. Se deducen varias consideraciones y conclusiones para una propuesta de conservación. Se proporcionan descripciones sobre el cuerpo del libro, el contenido de los cuadernillos, las capitales y algunas notas en papel.

Kontsert : 80ndad kindlalt tagasi. Tuleb

Index Scriptorium Estoniae

2007-01-01

Kontsertidest Tallinnas: Bryan Ferry 2. nov., Oslo Filharmoonia Orkester 29. aug.Estonia kontserdisaalis, kontsert "80's are back!" (esinevad Thomas Anders ja Ricci E Poveri) 18. okt. Saku Suurhallis, Grammyle kandideerinud USA metalcore'i bänd Killswitch Engage 15. okt. Club Hollywoodis

A classification system for one Killing vector solutions of Einstein's equations

International Nuclear Information System (INIS)

Hoenselaers, C.

1978-01-01

A double classification system for one Killing vector solutions in terms of the eigenvectors and eigenvalues of the Ricci and Bach tensor of the associated three manifold is proposed. The calculations of the Bach tensor are carried out for special cases. (author)

Medial Malleolar Fractures: An Anatomic Survey Determining the ...

African Journals Online (AJOL)

However, the literature lacks a defined method for selecting lag screw length, relying more ... Aim: The aim of this study is to help define the ideal lag screw length for medial melleolar fracture fixation. .... Biometrics 1977;33:159‑74. 8. Ricci WM ...

Geometric analysis

CERN Document Server

Bray, Hubert L; Mazzeo, Rafe; Sesum, Natasa

2015-01-01

This volume includes expanded versions of the lectures delivered in the Graduate Minicourse portion of the 2013 Park City Mathematics Institute session on Geometric Analysis. The papers give excellent high-level introductions, suitable for graduate students wishing to enter the field and experienced researchers alike, to a range of the most important areas of geometric analysis. These include: the general issue of geometric evolution, with more detailed lectures on Ricci flow and Kähler-Ricci flow, new progress on the analytic aspects of the Willmore equation as well as an introduction to the recent proof of the Willmore conjecture and new directions in min-max theory for geometric variational problems, the current state of the art regarding minimal surfaces in R^3, the role of critical metrics in Riemannian geometry, and the modern perspective on the study of eigenfunctions and eigenvalues for Laplace-Beltrami operators.

Geometric flows in Horava-Lifshitz gravity

CERN Document Server

Bakas, Ioannis; Lust, Dieter; Petropoulos, Marios

2010-01-01

We consider instanton solutions of Euclidean Horava-Lifshitz gravity in four dimensions satisfying the detailed balance condition. They are described by geometric flows in three dimensions driven by certain combinations of the Cotton and Ricci tensors as well as the cosmological-constant term. The deformation curvature terms can have competing behavior leading to a variety of fixed points. The instantons interpolate between any two fixed points, which are vacua of topologically massive gravity with Lambda > 0, and their action is finite. Special emphasis is placed on configurations with SU(2) isometry associated with homogeneous but generally non-isotropic Bianchi IX model geometries. In this case, the combined Ricci-Cotton flow reduces to an autonomous system of ordinary differential equations whose properties are studied in detail for different couplings. The occurrence and stability of isotropic and anisotropic fixed points are investigated analytically and some exact solutions are obtained. The correspond...

On the (1 + 3) threading of spacetime with respect to an arbitrary timelike vector field

Energy Technology Data Exchange (ETDEWEB)

Bejancu, Aurel [Kuwait University, Department of Mathematics, P.O.Box 5969, Safat (Kuwait); Calin, Constantin [Technical University ' ' Gh.Asachi' ' , Department of Mathematics, Iasi (Romania)

2015-04-15

We develop a newapproach on the (1 + 3) threading of spacetime (M, g) with respect to a congruence of curves defined by an arbitrary timelike vector field. The study is based on spatial tensor fields and on theRiemannian spatial connection ∇*, which behave as 3D geometric objects. We obtain new formulas for local components of the Ricci tensor field of (M, g) with respect to the threading frame field, in terms of the Ricci tensor field of ∇* and of kinematic quantities. Also, new expressions for time covariant derivatives of kinematic quantities are stated. In particular, a new form of Raychaudhuri's equation enables us to prove Lemma 6.3, which completes a well-known lemma used in the proof of the Penrose-Hawking singularity theorems. Finally, we apply the new (1 + 3) formalism to the study of the dynamics of a Kerr-Newman black hole. (orig.)

Tensors and their applications

CERN Document Server

Islam, Nazrul

2006-01-01

About the Book: The book is written is in easy-to-read style with corresponding examples. The main aim of this book is to precisely explain the fundamentals of Tensors and their applications to Mechanics, Elasticity, Theory of Relativity, Electromagnetic, Riemannian Geometry and many other disciplines of science and engineering, in a lucid manner. The text has been explained section wise, every concept has been narrated in the form of definition, examples and questions related to the concept taught. The overall package of the book is highly useful and interesting for the people associated with the field. Contents: Preliminaries Tensor Algebra Metric Tensor and Riemannian Metric Christoffel`s Symbols and Covariant Differentiation Riemann-Christoffel Tensor The e-Systems and the Generalized Krönecker Deltas Geometry Analytical Mechanics Curvature of a Curve, Geodesic Parallelism of Vectors Ricci`s Coefficients of Rotation and Congruence Hyper Surfaces

On relativistic generalization of Perelman's W-entropy and thermodynamic description of gravitational fields and cosmology

Energy Technology Data Exchange (ETDEWEB)

Vacaru, Olivia [National College of Iasi (Romania); Vacaru, Sergiu I. [Quantum Gravity Research, Topanga, CA (United States); University ' ' Al.I. Cuza' ' Iasi, Project IDEI, Iasi (Romania); Werner-Heisenberg-Institute, Max-Planck-Institute for Physics, Munich (Germany); Leibniz University of Hannover, Institute for Theoretical Physics (Germany); Ruchin, Vyacheslav

2017-03-15

Using double 2 + 2 and 3 + 1 nonholonomic fibrations on Lorentz manifolds, we extend the concept of W-entropy for gravitational fields in general relativity (GR). Such F- and W-functionals were introduced in the Ricci flow theory of three dimensional (3-d) Riemannian metrics by Perelman (the entropy formula for the Ricci flow and its geometric applications. arXiv:math.DG/0211159). Non-relativistic 3-d Ricci flows are characterized by associated statistical thermodynamical values determined by W-entropy. Generalizations for geometric flows of 4-d pseudo-Riemannian metrics are considered for models with local thermodynamical equilibrium and separation of dissipative and non-dissipative processes in relativistic hydrodynamics. The approach is elaborated in the framework of classical field theories (relativistic continuum and hydrodynamic models) without an underlying kinetic description, which will be elaborated in other work. The 3 + 1 splitting allows us to provide a general relativistic definition of gravitational entropy in the Lyapunov-Perelman sense. It increases monotonically as structure forms in the Universe. We can formulate a thermodynamic description of exact solutions in GR depending, in general, on all spacetime coordinates. A corresponding 2 + 2 splitting with nonholonomic deformation of linear connection and frame structures is necessary for generating in very general form various classes of exact solutions of the Einstein and general relativistic geometric flow equations. Finally, we speculate on physical macrostates and microstate interpretations of the W-entropy in GR, geometric flow theories and possible connections to string theory (a second unsolved problem also contained in Perelman's work) in Polyakov's approach. (orig.)

On the geometry of two-dimensional anisotropic non-linear Sigma-models

International Nuclear Information System (INIS)

Franco, D.H.; Negrao, M.G.; Helayel Neto, J.A.; Pereira, A.R.

1997-12-01

One discusses here the connection between α-model gauge anomalies and the existence of a connection with torsion that does not flatten the Ricci tensor of the target manifold. The influence of an eventual anisotropy along a certain internal direction is also contemplated. (author)

Environmental radioactivity in Canada - 1982

International Nuclear Information System (INIS)

Tracey, B.L.

1984-01-01

The radiological surveillance program of the Department of National Health and Welfare is conducted for the purpose of determining levels of environmental radioactivity in Canada and assessing the resulting population exposures. Special investigations were carried out during 1982 on metabolism of natural radionuclides and on the accumulation of radon in energy-efficient homes. The pre-operational phase of the monitoring program at the Point Lepreau Nuclear Generating Station was completed. Dose commitments have been estimated for the ongoing natural radioactivity, fallout and reactor studies. All measurements made during the year are below the limits recommended by the International Commission on Radiological Protection

Training for effective environmental protection in the nuclear industry

International Nuclear Information System (INIS)

Parkinson, D.; Brake, J.; Hickman, C.; Tamm, J.

2007-01-01

This paper examines the role of environmental training in the delivery of effective environmental protection programs for construction projects in the nuclear industry. The paper uses a case study approach, based on Point Lepreau Generating Station's Refurbishment Project, to demonstrate how the underpinning principles of 'training, awareness and competence' can be delivered within a structured environmental management framework, to achieve sustained excellence in environmental management and performance. Key issues addressed by the paper include the early identification of different target audiences, making effective use of communication themes, and the importance of reinforcement and follow-up in support of training goals. (author)

A strategy for the phased replacement of CANDU digital control computers

International Nuclear Information System (INIS)

Hepburn, G.A.

2001-01-01

Significant developments have occurred with respect to the replacement of the Plant Digital Control Computers (DCCs) on CANDU plants in the past six months. This paper summarises the conclusions of the condition assessment carried out on these machines at Point Lepreau Generating Station, and describes a strategy for a phased transition to a replacement system based on today's technology. Most elements of the strategy are already in place, and sufficient technical work has been done to allow those components which have been assessed as requiring prompt attention to be replaced in a matter of months. (author)

Industry partnership: adding value to nuclear refurbishment and maintenance

International Nuclear Information System (INIS)

Gibbins, T.; Bains, N.; Morikawa, D.

2008-01-01

The Point Lepreau Generating Station was the first CANDU 6 unit to be licensed for operation, beginning commercial operation in 1983. It is now become the first CANDU 6 to undergo full refurbishment. As part of the overall project, all 380 fuel channels and associated feeders will be removed and replaced. In order to undertake this project, it was necessary for AECL to design and develop over fifty 'first-of-a-kind tools' for fuel channel and calandria tube replacement. This paper outlines the complexity of the retube tooling project and the industry partnership strategy for the engineered tooling systems development. (author)

1001 filmi nagu punane rätik härjale / Tiit Tuumalu

Index Scriptorium Estoniae

Tuumalu, Tiit, 1971-

2004-01-01

Inglise originaalist tõlgitud ligi 1000-leheküljeline teatmeteos "1001 filmi, mida elu jooksul peab nägema" (toimetaja Steven Jay Schneider). Artiklile lisatud filmikriitikute Jaan Ruusi ja Lauri Kärgi kommentaarid

Nägemine piltide kaudu : Fotograafia antropoloogiast / Jay Ruby

Index Scriptorium Estoniae

Ruby, Jay, 1935-

2010-01-01

Fotograafia ja sotsiaalteaduste suhtest visuaalse etnograafia seisukohalt. Uurimisprojektist, mille sihiks on mõista kõikide fotograafia liikide kultuurilist rolli ja funktsioone inimeste elus antropoloogilisest vaatenurgast, olles huvitatud kultuurilisest ja kommunikatiivsest, mitte hinnangulisest algest

LDL Particle Testing

Science.gov (United States)

... P. Caulfield, Jay Wohlgemuth, Zhizong Chen, Robert Superko, Charles M. Rowland, Robert J. Glynn, Paul M. Ridker, ... See Less Ask a Laboratory Scientist Your questions will be answered by a laboratory scientist as part ...

New Toys For Old Games: eBooks – iTroubles

OpenAIRE

Jay Himes; Meegan Hollywood

2012-01-01

While the innovations of Apple may reflect significant industry advances and offer considerable consumer benefits, still, the antitrust laws cannot be jettisoned to accomplish such goals. Jay L. Himes & Meegan Hollywood (Labaton Sucharow LLP)

Marginally Deformed Starobinsky Gravity

DEFF Research Database (Denmark)

Codello, A.; Joergensen, J.; Sannino, Francesco

2015-01-01

We show that quantum-induced marginal deformations of the Starobinsky gravitational action of the form $R^{2(1 -\\alpha)}$, with $R$ the Ricci scalar and $\\alpha$ a positive parameter, smaller than one half, can account for the recent experimental observations by BICEP2 of primordial tensor modes....

A General Expression for the Quintic Lovelock Tensor

OpenAIRE

Briggs, C. C.

1996-01-01

A general expression is given for the quintic Lovelock tensor as well as for the coefficient of the quintic Lovelock Lagrangian in terms of the Riemann-Christoffel and Ricci curvature tensors and the Riemann curvature scalar for n-dimensional differentiable manifolds having a general linear connection.

Negociação penal, legitimação jurídica e poderes urbanos na Itália comunal

Directory of Open Access Journals (Sweden)

Andréa Zorzi

2007-07-01

Full Text Available O artigo foca o pensamento do juristaestado-unidense Francis Jay Mootz, professorde Direito na Penn State University, destacandoa intersecção que promove entre o Direito e ahermenêutica filosófica. Os temas descortinadosconcentram-se em torno do debate sobre a relaçãoentre teoria e prática no Direito, o intercâmbiointerdisciplinar e o enfoque do universo jurídicocomo produtor de um conhecimento retórico.The article focus the work of Francis JayMootz, a jurist from the USA who is law professorin the Penn State University. It emphasizes theintersection that this author promotes between lawand philosophical hermeneutics. The discussedsubjects are the relationship between theory andpractice in law, the interdisciplinary exchange andthe focus over the juridical field as a rhetoricalknowledge producer.

On the near horizon rotating black hole geometries with NUT charges

Energy Technology Data Exchange (ETDEWEB)

Galajinsky, Anton; Orekhov, Kirill [Tomsk Polytechnic University, Laboratory of Mathematical Physics, Tomsk (Russian Federation)

2016-09-15

The near horizon geometries are usually constructed by implementing a specific limit to a given extreme black hole configuration. Their salient feature is that the isometry group includes the conformal subgroup SO(2, 1). In this work, we turn the logic around and use the conformal invariants for constructing Ricci-flat metrics in d = 4 and d = 5 where the vacuum Einstein equations reduce to a coupled set of ordinary differential equations. In four dimensions the analysis can be carried out in full generality and the resulting metric describes the d = 4 near horizon Kerr-NUT black hole. In five dimensions we choose a specific ansatz whose structure is similar to the d = 5 near horizon Myers-Perry black hole. A Ricci-flat metric involving five arbitrary parameters is constructed. A particular member of this family, which is characterized by three parameters, seems to be a natural candidate to describe the d = 5 near horizon Myers- Perry black hole with a NUT charge. (orig.)

Renormalization group scale-setting from the action—a road to modified gravity theories

International Nuclear Information System (INIS)

Domazet, Silvije; Štefančić, Hrvoje

2012-01-01

The renormalization group (RG) corrected gravitational action in Einstein–Hilbert and other truncations is considered. The running scale of the RG is treated as a scalar field at the level of the action and determined in a scale-setting procedure recently introduced by Koch and Ramirez for the Einstein–Hilbert truncation. The scale-setting procedure is elaborated for other truncations of the gravitational action and applied to several phenomenologically interesting cases. It is shown how the logarithmic dependence of the Newton's coupling on the RG scale leads to exponentially suppressed effective cosmological constant and how the scale-setting in particular RG-corrected gravitational theories yields the effective f(R) modified gravity theories with negative powers of the Ricci scalar R. The scale-setting at the level of the action at the non-Gaussian fixed point in Einstein–Hilbert and more general truncations is shown to lead to universal effective action quadratic in the Ricci tensor. (paper)

Renormalization group scale-setting from the action—a road to modified gravity theories

Science.gov (United States)

Domazet, Silvije; Štefančić, Hrvoje

2012-12-01

The renormalization group (RG) corrected gravitational action in Einstein-Hilbert and other truncations is considered. The running scale of the RG is treated as a scalar field at the level of the action and determined in a scale-setting procedure recently introduced by Koch and Ramirez for the Einstein-Hilbert truncation. The scale-setting procedure is elaborated for other truncations of the gravitational action and applied to several phenomenologically interesting cases. It is shown how the logarithmic dependence of the Newton's coupling on the RG scale leads to exponentially suppressed effective cosmological constant and how the scale-setting in particular RG-corrected gravitational theories yields the effective f(R) modified gravity theories with negative powers of the Ricci scalar R. The scale-setting at the level of the action at the non-Gaussian fixed point in Einstein-Hilbert and more general truncations is shown to lead to universal effective action quadratic in the Ricci tensor.

Geometric flows and (some of) their physical applications

CERN Document Server

Bakas, Ioannis

2005-01-01

The geometric evolution equations provide new ways to address a variety of non-linear problems in Riemannian geometry, and, at the same time, they enjoy numerous physical applications, most notably within the renormalization group analysis of non-linear sigma models and in general relativity. They are divided into classes of intrinsic and extrinsic curvature flows. Here, we review the main aspects of intrinsic geometric flows driven by the Ricci curvature, in various forms, and explain the intimate relation between Ricci and Calabi flows on Kahler manifolds using the notion of super-evolution. The integration of these flows on two-dimensional surfaces relies on the introduction of a novel class of infinite dimensional algebras with infinite growth. It is also explained in this context how Kac's K_2 simple Lie algebra can be used to construct metrics on S^2 with prescribed scalar curvature equal to the sum of any holomorphic function and its complex conjugate; applications of this special problem to general re...

On the near horizon rotating black hole geometries with NUT charges

International Nuclear Information System (INIS)

Galajinsky, Anton; Orekhov, Kirill

2016-01-01

The near horizon geometries are usually constructed by implementing a specific limit to a given extreme black hole configuration. Their salient feature is that the isometry group includes the conformal subgroup SO(2, 1). In this work, we turn the logic around and use the conformal invariants for constructing Ricci-flat metrics in d = 4 and d = 5 where the vacuum Einstein equations reduce to a coupled set of ordinary differential equations. In four dimensions the analysis can be carried out in full generality and the resulting metric describes the d = 4 near horizon Kerr-NUT black hole. In five dimensions we choose a specific ansatz whose structure is similar to the d = 5 near horizon Myers-Perry black hole. A Ricci-flat metric involving five arbitrary parameters is constructed. A particular member of this family, which is characterized by three parameters, seems to be a natural candidate to describe the d = 5 near horizon Myers- Perry black hole with a NUT charge. (orig.)

Reference: 197 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available bidopsis thaliana CAX2 cation transporter. 6 959-71 15821993 2004 Dec Plant molecular biology Cheng Ning-Hui|Hirschi Kendal D|Marshall Joy L|Morris Jay L|Pittman Jon K|Shigaki Toshiro

Plaadid / Mari Rebane, Heidi Purga, Tiiu Laks...[jt.

Index Scriptorium Estoniae

2008-01-01

Uutest heliplaatidest Sigur Ros "Heim/Hvart", Jay-Z "American Gangster", Bob Marley and The Wailers "Roots, Rock, Remixed", Ghostface killah "The Big doe Rehab", Backstreet Boys "Unbreakable", Matchbox Twenty "Exile on Mainstream", "Just" Hits 6"

Sound / Märt Milter

Index Scriptorium Estoniae

Milter, Märt

1999-01-01

Kosmos Control muusikapoes müügilolevatest tantsumuusika plaatidest.Lisaks Miixmag Live seeria plaatidele veel Jesus Jones "Doubt", Kenny Hawkes "Space", "Journey By DJ. Gilles Peterson. Norman Jay", Ice Cube "Kill At Will", Wedding Present "Tommy"

The Oxford book of modern science writing

National Research Council Canada - National Science Library

Dawkins, Richard

2008-01-01

..." to "the terror and vastness of the universe." Edited by renowned scientist Richard Dawkins, this collection brings together pieces by a who's who of scientists and science writers, including Stephen Pinker, Stephen Jay Gould, Martin Gardner...

Resonance – Journal of Science Education | Indian Academy of ...

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 3. Plant Growth Promoting Rhizobacteria - Potential Microbes for Sustainable Agriculture. Jay Shankar Singh. General Article Volume 18 Issue 3 March 2013 pp 275-281 ...

Haz-Map: Information on Hazardous Chemicals and Occupational Diseases

Science.gov (United States)

... Help Glossary References About Us Search Hazardous Agents Occupational Diseases High Risk Jobs Non-Occupational Activities Industries Job ... Findings Haz-Map®: Information on Hazardous Chemicals and Occupational Diseases by Jay A. Brown, M.D., M.P. ...

Development of the Young Brain

Medline Plus

Full Text Available ... Traumatic Events (3 items) Institute Announcements (24 items) Development of the Young Brain May 2, 2011 For ... Health neuroscientist Dr. Jay Giedd has studied the development of the adolescent brain. Decades of imaging work ...

Development of the Young Brain

Medline Plus

Full Text Available ... life work of National Institute of Mental Health researcher Dr. Jay Giedd. Dr. Giedd: At different ages ... so these changes are a real challenge for researchers because they happen so rapidly. So, that adolescents ...

Development of the Young Brain

Medline Plus

Full Text Available ... Health researcher Dr. Jay Giedd. Dr. Giedd: At different ages of life certain parts of the brain have much more dynamic growth than at other times. And so for very early in life we ...

Plaadid / Heidi Purga

Index Scriptorium Estoniae

Purga, Heidy, 1975-

2006-01-01

Uutest heliplaatidest Gwen Stefani "The Sweet Escape", Errors "How Clean Is Your Acid House?", Cliff Richard "Two's Company", Jay-Z "Kingdom Come", Incubus "Light Grenades", Pogo Kreiner & Vienna Sound Orchestra "E"Magic Flute", Freddie Cruger "Soul Search"

Development of the Young Brain

Medline Plus

Full Text Available ... development of the adolescent brain has been the life work of National Institute of Mental Health researcher ... Jay Giedd. Dr. Giedd: At different ages of life certain parts of the brain have much more ...

supp2.doc

Indian Academy of Sciences (India)

Panneerselvam Anithaa, Rajendran Manikandana, Paranthaman Vijayana, Govindan Prakasha, Periasamy Viswanathamurthia,* and Ray Jay Butcherb. a Department of Chemistry, Periyar University, Salem-636011, Tamil Nadu, India. b Department of Chemistry, Howard University, 525 College Street NW, Washington, DC ...

Development of the Young Brain

Medline Plus

Full Text Available ... researcher Dr. Jay Giedd. Dr. Giedd: At different ages of life certain parts of the brain have ... tasking in many ways brought on by the age of social media and use of computer gadgets. ...

Critical safety parameters: The logical approach to refresher training

International Nuclear Information System (INIS)

Johnson, A.R.; Pilkington, W.; Turner, S.

1991-01-01

Nuclear power plant managers must ensure that control room staff are able to perform effectively. This is of particular importance through the longer term after initial authorization. Traditionally refresher training has been based on delivery of fragmented training packages typically derived from the initial authorization training programs. Various approaches have been taken to provide a more integrated refresher training program. However, methods such as job and task analysis and subject matter expert derived training have tended to develop without a focused clear overall training objective. The primary objective of all control room staff training is to ensure a proper and safe response to all plant transients. At the Point Lepreau Nuclear Plant, this has defined the Critical Safety Parameter based refresher training program. The overall objective of the Critical Safety Parameter training program is to ensure that control room staff can monitor and control a discrete set of plant parameters. Maintenance of the selected parameters within defined boundaries assures adequate cooling of the fuel and containment of radioactivity. Control room staff need to be able to reliably respond correctly to plant transients under potentially high stress conditions,. utilizing the essential knowledge and skills to deal with such transients. The inference is that the knowledge and skills must be limited to that which can be reliably recalled. This paper describes how the Point Lepreau Nuclear Plant has developed a refresher training program on the basis of a limited number of Critical Safety Parameters. Through this approach, it has been possible to define the essential set of knowledge and skills which ensures a correct response to plant transients

Development of the Young Brain

Medline Plus

Full Text Available ... development of the adolescent brain has been the life work of National Institute of Mental Health researcher Dr. Jay Giedd. Dr. Giedd: At different ages of life certain parts of the brain have much more ...

Stsenaristide maja / Lauri Saaber

Index Scriptorium Estoniae

Saaber, Lauri

2000-01-01

Režissöör Jay Roachì komöödiast "Kuum, kuum Alaska" ("Mystery, Alaska") ja Sydney Pollacki põnevusfilmist Warren Adleri romaani järgi "Pettuse võrgus" ("Random Hearts") : Ameerika Ühendriigid 1999

Research Article Special Issue

African Journals Online (AJOL)

pc

2017-11-24

Nov 24, 2017 ... successful application of this approach for creating mathematical models and their use in ...... Jay C. Hsu, Andrew U. Meyer, Modern control principles and applications: - New-York: McGraw-hill book company, 1972 – 544pp.

Visions for Literacy: Parents' Aspirations for Reading in Children with Down Syndrome

Science.gov (United States)

Ricci, Leila; Osipova, Anna

2012-01-01

Although children with Down syndrome (DS) can learn to read, few studies have explored parental perspectives on the reading development of this group of children. This article, written by Leila Ricci and Anna Osipova, from California State University, explores visions and expectations regarding reading held by parents of children with Down…

Massive, massless and ghost modes of gravitational waves from higher-order gravity

DEFF Research Database (Denmark)

Bogdanos, Charalampos; Capozziello, Salvatore; De Laurentis, Mariafelicia

We linearize the field equations for higher order theories that contain scalar invariants other than the Ricci scalar. We find that besides a massless spin-2 field (the standard graviton), the theory contains also spin-0 and spin-2 massive modes with the latter being, in general, ghost modes. Then...

Manifolds of positive scalar curvature

Energy Technology Data Exchange (ETDEWEB)

Stolz, S [Department of Mathematics, University of Notre Dame, Notre Dame (United States)

2002-08-15

This lecture gives an survey on the problem of finding a positive scalar curvature metric on a closed manifold. The Gromov-Lawson-Rosenberg conjecture and its relation to the Baum-Connes conjecture are discussed and the problem of finding a positive Ricci curvature metric on a closed manifold is explained.

Development of the Young Brain

Medline Plus

Full Text Available ... Jay Giedd has studied the development of the adolescent brain. Decades of imaging work have led to remarkable ... and intellectual growth. Studying the development of the adolescent brain has been the life work of National Institute ...

Baby Poop: What's Normal?

Science.gov (United States)

... I'm breast-feeding my newborn and her bowel movements are yellow and mushy. Is this normal for baby poop? Answers from Jay L. Hoecker, M.D. Yellow, mushy bowel movements are perfectly normal for breast-fed babies. Still, ...

Recent digital control and protection retrofits in power plants

International Nuclear Information System (INIS)

Fournier, R.D.; Hammer, M.; Smith, J.E.

1987-01-01

Digital computers are now being retrofitted to all types of power plants, replacing analog equipment and solving problems such as equipment obsolescence and low reliability. Three diverse examples of retrofits are presented in this paper, representing trends in man/machine interface design at an oil-fired plant, protection system in pressurized heavy-water reactors, and control systems in light water reactors (LWRs). The examples have been chosen to illustrate diverse reasons for the retrofits and the benefits derived. The cases presented report retrofits at Northern States Power's Monticello boiling water reactor, New Brunswick Electric Power Commission's (NBEPC's) Point Lepreau Nuclear Generating Station, and finally NBEPC's oil-fired plant at Courtney Bay

Manpower development for safe operation of nuclear power plant. China. Seminar on the technical support functions. Activity: 6.1.1-Task-03. Technical report

International Nuclear Information System (INIS)

Groom, S.H.

1994-01-01

The workshop which was intended to present operating experiences from utilities with a wide range of numbers of operating nuclear units. The speaker, S.H. Groom, presented N.B. Power's experience with a single nuclear unit, and intended to: Present the objectives, organization, and scope of work of the central and site Technical Service groups within N.B. Power which support the operation of the Point Lepreau NGS; Define responsibilities of, and interfaces between the on-site and the central technical service staff; Recommend methods for the establishment and maintenance of an efficient technical support group for the operation of any nuclear power plant

Review of first line supervisory positions in nuclear power plants - Phase II

Energy Technology Data Exchange (ETDEWEB)

Mackenzie, C W; Huntley, M [Hickling Corp., Ottawa, ON (Canada)

1995-10-01

This report provides an overview of first line supervisory activities at Ontario Hydro nuclear generating stations (Pickering `A` and Bruce `B`) and the Point Lepreau nuclear generating station in New Brunswick. Activity profiles describing the range of first line supervisory roles and responsibilities for nuclear operators have been developed from survey data and flowcharting methods. These activity profiles have then been compared with formal job responsibilities as identified in job descriptions, supervisory training provided and assessment criteria used to evaluate supervisors. Finally, this report relates the findings of supervisory practices in the group under study with the findings in the current literature relating to supervisory functioning. (author). 32 tabs., 2 figs.

Review of first line supervisory positions in nuclear power plants - Phase II

International Nuclear Information System (INIS)

Mackenzie, C.W.; Huntley, M.

1995-10-01

This report provides an overview of first line supervisory activities at Ontario Hydro nuclear generating stations (Pickering 'A' and Bruce 'B') and the Point Lepreau nuclear generating station in New Brunswick. Activity profiles describing the range of first line supervisory roles and responsibilities for nuclear operators have been developed from survey data and flowcharting methods. These activity profiles have then been compared with formal job responsibilities as identified in job descriptions, supervisory training provided and assessment criteria used to evaluate supervisors. Finally, this report relates the findings of supervisory practices in the group under study with the findings in the current literature relating to supervisory functioning. (author). 32 tabs., 2 figs

Harmonic manifolds with minimal horospheres are flat

Indian Academy of Sciences (India)

Abstract. In this note we reprove the known theorem: Harmonic manifolds with minimal horospheres are flat. It turns out that our proof is simpler and more direct than the original one. We also reprove the theorem: Ricci flat harmonic manifolds are flat, which is generally affirmed by appealing to Cheeger–Gromov splitting ...

Harmonic Manifolds with Minimal Horospheres are Flat

Indian Academy of Sciences (India)

In this note we reprove the known theorem: Harmonic manifolds with minimal horospheres are flat. It turns out that our proof is simpler and more direct than the original one. We also reprove the theorem: Ricci flat harmonic manifolds are flat, which is generally affirmed by appealing to Cheeger–Gromov splitting theorem.

Controls on terrigenous sediment supply to the Arabian Sea during the late Quaternary: the Indus Fan.

NARCIS (Netherlands)

Prins, M.A.; Postma, G.; Cleveringa, J.; Cramp, A.; Kenyon, N.H.

2000-01-01

A previous study on the basis of long-range side-scan sonar data (Kenyon et al., 1995. Geometry of the younger sediment bodies of the Indus Fan. In: Pickering, K.T., Hiscott, R.N., Kenyon, N.H., Ricci Lucchi, F., Smith, R.D.A. (Eds.), Atlas of deep water environments: architectural style in

Gravitational peculiarities of a scalar field

International Nuclear Information System (INIS)

Kleber, A.; Fonseca Teixeira, A.F. da

1979-11-01

The zero-adjoint of a time-static Ricci-flat solution to Einstein's field equations is investigated. It represents a spacetime curved solely by a massless scalar field. The cylindrical symmetry is assumed to permit both planar and non-planar geodetic motions. Unusual, velocity-dependent gravitational features are encountered from these geodesics. (Author) [pt

Finiteness of Ricci flat supersymmetric non-linear sigma-models

International Nuclear Information System (INIS)

Alvarez-Gaume, L.; Ginsparg, P.

1985-01-01

Combining the constraints of Kaehler differential geometry with the universality of the normal coordinate expansion in the background field method, we study the ultraviolet behavior of 2-dimensional supersymmetric non-linear sigma-models with target space an arbitrary riemannian manifold M. We show that the constraint of N=2 supersymmetry requires that all counterterms to the metric beyond one-loop order are cohomologically trivial. It follows that such supersymmetric non-linear sigma-models defined on locally symmetric spaces are super-renormalizable and that N=4 models are on-shell ultraviolet finite to all orders of perturbation theory. (orig.)

Initial Spare Parts of the A400M Aircraft

Science.gov (United States)

2012-03-08

inventory. Therefore, a balance has to be sought between inventory cost and customer service ( Heizer & Render , 2010:500-501). Nevertheless, spare part... Heizer , Jay H. and Barry Render . Principles of Operations Management. Boston: Pearson Education, 2011. Heuninckx, Baudouin. “Availability

South African Journal of Surgery - Vol 55, No 1 (2017)

African Journals Online (AJOL)

The circumareolar approach to gynecomastia and transgender surgery: modifications to provide correct nipple areolar complex position and shape · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. T Jay, K Segwapa, 16-20 ...

Development of the Young Brain

Medline Plus

Full Text Available ... been fascinated with the development of children- their physical and intellectual growth. Studying the development of the adolescent brain has been the life work of National Institute of Mental Health researcher Dr. Jay Giedd. Dr. Giedd: At different ...

Development of the Young Brain

Medline Plus

Full Text Available ... been fascinated with the development of children- their physical and intellectual growth. Studying the development of the adolescent brain has been the life work of National Institute of Mental Health researcher Dr. Jay Giedd. Dr. Giedd: At ...

Uusika Muudised

Index Scriptorium Estoniae

2004-01-01

Iiri ansambli Westlife uuest ilmuvast singlist ; Robi Williamsi uuest raamatust ja menulaulude albumist "Feel" ; MTV muusikavideo auhinna nominatsioonide edetabeli liider räppar Jay-Z ; Atomic Kitteni endise liikme Jenny Frosti pulmadest ; Saksa ansambli Rammstein kontserdist Saku Suurhallis 22. novembril

Brain Morphometry on Congenital Hand Deformities based on Teichmüller Space Theory.

Science.gov (United States)

Peng, Hao; Wang, Xu; Duan, Ye; Frey, Scott H; Gu, Xianfeng

2015-01-01

Congenital Hand Deformities (CHD) are usually occurred between fourth and eighth week after the embryo is formed. Failure of the transformation from arm bud cells to upper limb can lead to an abnormal appearing/functioning upper extremity which is presented at birth. Some causes are linked to genetics while others are affected by the environment, and the rest have remained unknown. CHD patients develop prehension through the use of their hands, which affect the brain as time passes. In recent years, CHD have gain increasing attention and researches have been conducted on CHD, both surgically and psychologically. However, the impacts of CHD on brain structure are not well-understood so far. Here, we propose a novel approach to apply Teichmüller space theory and conformal welding method to study brain morphometry in CHD patients. Conformal welding signature reflects the geometric relations among different functional areas on the cortex surface, which is intrinsic to the Riemannian metric, invariant under conformal deformation, and encodes complete information of the functional area boundaries. The computational algorithm is based on discrete surface Ricci flow, which has theoretic guarantees for the existence and uniqueness of the solutions. In practice, discrete Ricci flow is equivalent to a convex optimization problem, therefore has high numerically stability. In this paper, we compute the signatures of contours on general 3D surfaces with surface Ricci flow method, which encodes both global and local surface contour information. Then we evaluated the signatures of pre-central and post-central gyrus on healthy control and CHD subjects for analyzing brain cortical morphometry. Preliminary experimental results from 3D MRI data of CHD/control data demonstrate the effectiveness of our method. The statistical comparison between left and right brain gives us a better understanding on brain morphometry of subjects with Congenital Hand Deformities, in particular, missing

Half-flat structures on S3×S3

DEFF Research Database (Denmark)

Madsen, Thomas Bruun; Salamon, Simon

We classify left-invariant half-flat SU(3)-structures on S3 × S3, using the representation theory of SO(4) and matrix algebra. This leads to a systematic study of the associated cohomogeneity one Ricci-flat metrics with holonomy G2 obtained on 7-manifolds with equidistant S3 × S3 hypersurfaces...

Warped products and black holes

International Nuclear Information System (INIS)

Hong, Soon-Tae

2005-01-01

We apply the warped product space-time scheme to the Banados-Teitelboim-Zanelli black holes and the Reissner-Nordstroem-anti-de Sitter black hole to investigate their interior solutions in terms of warped products. It is shown that there exist no discontinuities of the Ricci and Einstein curvatures across event horizons of these black holes

Targeted Magnetic Hyperthermia for Lung Cancer

Science.gov (United States)

2014-11-01

1171:583- 590 . 32. Colell, A., Ricci, J.E., Tait, S., Milasta, S., Maurer, U., Bouchier-Hayes, L., Fitzgerald, P., Guio-Carrion, A., Waterhouse, N.J...and spectroscopic detection with surface-enhanced Raman nanoparticle tags. Nat Biotechnol 2008;26(1):83e90. [7] Lee H, Lee E, Kim do K, Jang NK, Jeong

Numerical Calabi-Yau metrics

International Nuclear Information System (INIS)

Douglas, Michael R.; Karp, Robert L.; Lukic, Sergio; Reinbacher, Rene

2008-01-01

We develop numerical methods for approximating Ricci flat metrics on Calabi-Yau hypersurfaces in projective spaces. Our approach is based on finding balanced metrics and builds on recent theoretical work by Donaldson. We illustrate our methods in detail for a one parameter family of quintics. We also suggest several ways to extend our results

Regulating the infrared by mode matching: a massless scalar in expanding spaces with constant deceleration

NARCIS (Netherlands)

Janssen, T.M.; Prokopec, T.

2011-01-01

In this paper we consider a massless scalar field, with a possible coupling ξ to the Ricci scalar in a D dimensional Friedmann-Lemaître-Robertson-Walker space-time with a constant deceleration parameter q=ϵ-1, ϵ=-H˙/H2. Correlation functions for the Bunch-Davies vacuum of such a theory have long

Pramana – Journal of Physics | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Pramana – Journal of Physics; Volume 56; Issue 5. Volume 56, Issue 5. May 2001, pages 591-703 and L705-L713. pp 591-596 Research Articles. On conformally related -waves · Varsha Daftardar-Gejji · More Details Abstract Fulltext PDF. Brinkmann [1] has shown that conformally related distinct Ricci ...

Don't Bother Me, I'm Reading: Graphic Nonfiction for Middle Schoolers

Science.gov (United States)

Gutierrez, Peter

2008-01-01

This article offers a savvy guide to the best graphic nonfiction books for middle schoolers. These include: "Ronald Reagan: A Graphic Biography" by Andrew Hefler; "Clan Apis" by Jay Hosler; and "Corpses and Skeletons: The Science of Forensic Anthropology" by Rob Shone.

Environmental Investigations and Analyses for Los Angeles-Long Beach Harbors, Los Angeles, California, 1973-1976.

Science.gov (United States)

1976-12-01

Christine Yonai Fred Piltz Ichthyology Jay Carroll Karl Lyde John Helle Scott Ralston S. Ishikawa Steve Subber Catherine Kusick Catherine Terry...Charles Greaves Catherine Link Susan Harrison Julie Thompson Kaoru 0. Kendis Ismay Stanley Randall Kendis Marine Technicians Bruce Adams Gene Mummert

78 FR 43854 - Designation for the Muncie, IN; Fremont, NE; Annapolis, MD; and West Lafayette, IN Areas...

Science.gov (United States)

2013-07-22

..., Hendricks, Henry, Jay, Johnson, Madison, Marion, Monroe, Morgan, Randolph, Rush, Shelby, Union, and Wayne Counties. In Ohio Darke County. This designation action to provide official services in these specified... Cooperative elevator located in Shelby, Polk County, Nebraska. Correction In the Federal Register Notice...

Pop / Margus Kiis

Index Scriptorium Estoniae

Kiis, Margus

2008-01-01

Heliplaatidest: Raadio Maria "Siin Tallinn", Aretha Franklin "Rare & Unreleased Recordings: From The Golden Reign Of The Queen Of Soul", David Shrigley "David Shrigley's Worried Noodles", Hurt "Vol. II", Queen Latifah "Trav'lin' Light", Juanes "La Vida... Es Un Ratico", Jay-Z "American Gangster"

Plaadid / Heidi Purga

Index Scriptorium Estoniae

Purga, Heidy, 1975-

2006-01-01

Uutest heliplaatidest Jay Dee/J Dilla "Donuts", The Strokes "First Impressions Of Earth", Jools Holland & His R&B orchestra "Swinging the Blues, Dancing The Ska", "The Sound Of Music", Karin Clercq "Apres l'amour", Mest "Photographs", The Notorious B.I.G. "Duets"

Hingedekuu menufilmid / Riina Sildos

Index Scriptorium Estoniae

Sildos, Riina

1999-01-01

Romantiline komöödia "Põgenev pruut" : režissöör Garry Marshall : Ameerika Ühendriigid 1999 ja komöödia "Austin Powers : Spioon, kes kargas mind" : režissöör Jay Roach : Ameerika Ühendriigid 1999

Pop / Tõnis Kahu

Index Scriptorium Estoniae

Kahu, Tõnis, 1962-

2005-01-01

Heliplaatidest: Tori Amos "The Beekeeper", 3 Doors Down "Seventeen Days", Jay-Z / Linkin Park "Collision Course", Patrick Moraz / Bill Bruford "Flags", Shuttle358 "Chessa", Erasure "Nightbird", Erinevad esitajad "Kingston 5 Presents The New Sound of Reggae", Ryuichi Sakamoto "Chasm", Ryuichi Sakamoto "Derrida"

Põrguvürst ja pruudi isa / Lauri Saaber

Index Scriptorium Estoniae

Saaber, Lauri

2001-01-01

Komöödiatest "Kohtumine äiaga" ("Meet the Parents") : režissöör Jay Roach : peaosas Robert DeNiro : Ameerika Ühendriigid 2000 ja "Võrgutav saatan" ("Bedazzled") : režissöör Harold Ramis : Ameerika Ühendriigid 2000

Gravitational collapse and topology change in spherically symmetric dynamical systems

Energy Technology Data Exchange (ETDEWEB)

Csizmadia, Peter; Racz, Istvan, E-mail: cspeter@rmki.kfki.h, E-mail: iracz@rmki.kfki.h [RMKI H-1121 Budapest, Konkoly Thege Miklos ut 29-33 (Hungary)

2010-01-07

A new numerical framework, based on the use of a simple first-order strongly hyperbolic evolution equations, is introduced and tested in the case of four-dimensional spherically symmetric gravitating systems. The analytic setup is chosen such that our numerical method is capable of following the time evolution even after the appearance of trapped surfaces, more importantly, until the true physical singularities are reached. Using this framework, the gravitational collapse of various gravity-matter systems is investigated, with particular attention to the evolution in trapped regions. It is verified that, in advance of the formation of these curvature singularities, trapped regions develop in all cases, thereby supporting the validity of the weak cosmic censor hypothesis of Penrose. Various upper bounds on the rate of blow-up of the Ricci and Kretschmann scalars and the Misner-Sharp mass are provided. In spite of the unboundedness of the Ricci scalar, the Einstein-Hilbert action was found to remain finite in all the investigated cases. In addition, important conceptual issues related to the phenomenon of topology changes are discussed.

Gravitational radiation from nearly Newtonian systems

International Nuclear Information System (INIS)

Kirk, E.M.

1989-09-01

A method of examining gravitational radiation from nearly Newtonian systems is presented. Using the Cartan formulation of Newtonian gravity, a one parameter family of space-times which have a strict Newtonian limit is constructed. An expression for the initial null data in terms of the Newtonian potential is obtained in the Newtonian limit. Using this, the problem is formulated as a series in the Newtonian parameter. The series expansions for the sources of the Bianchi identities are obtained to third order in both the vacuum and non-vacuum cases. A simple technique is presented for determining whether a particular source term gives rise to asymptotically flat null data. The far field quadrupole formula is derived in a leading approximation and a method for obtaining error bounds is discussed. Additionally, a method for solving Einstein's equations is shown. This involves expressing the Ricci identities as a matrix, Riccati equation and a system of linear matrix equations. A comparison of the formalisms of Bondi and Newman Penrose is presented and explicit correspondences between the supersurface constrain equations and the Ricci identities are shown. (author)

Geometric properties of static Einstein-Maxwell dilaton horizons with a Liouville potential

International Nuclear Information System (INIS)

Abdolrahimi, Shohreh; Shoom, Andrey A.

2011-01-01

We study nondegenerate and degenerate (extremal) Killing horizons of arbitrary geometry and topology within the Einstein-Maxwell-dilaton model with a Liouville potential (the EMdL model) in d-dimensional (d≥4) static space-times. Using Israel's description of a static space-time, we construct the EMdL equations and the space-time curvature invariants: the Ricci scalar, the square of the Ricci tensor, and the Kretschmann scalar. Assuming that space-time metric functions and the model fields are real analytic functions in the vicinity of a space-time horizon, we study the behavior of the space-time metric and the fields near the horizon and derive relations between the space-time curvature invariants calculated on the horizon and geometric invariants of the horizon surface. The derived relations generalize similar relations known for horizons of static four- and five-dimensional vacuum and four-dimensional electrovacuum space-times. Our analysis shows that all the extremal horizon surfaces are Einstein spaces. We present the necessary conditions for the existence of static extremal horizons within the EMdL model.

Algebraic Rainich conditions for the fourth rank tensor V

International Nuclear Information System (INIS)

So, Lau Loi

2011-01-01

Algebraic conditions on the Ricci tensor in the Rainich-Misner-Wheeler unified field theory are known as the Rainich conditions. Penrose and more recently Bergqvist and Lankinen made an analogy from the Ricci tensor to the Bel-Robinson tensor B αβμν , a certain fourth rank tensor quadratic in the Weyl curvature, which also satisfies algebraic Rainich-like conditions. However, we found that not only does the tensor B αβμν fulfill these conditions, but so also does our recently proposed tensor V αβμν , which has many of the desirable properties of B αβμν . For the quasilocal small sphere limit restriction, we found that there are only two fourth rank tensors, B αβμν and V αβμν , which form a basis for good energy expressions. Both of them have the completely trace free and causal properties, these two form necessary and sufficient conditions. Surprisingly either completely traceless or causal is enough to fulfill the algebraic Rainich conditions.

AdS Black Hole with Phantom Scalar Field

Directory of Open Access Journals (Sweden)

Limei Zhang

2017-01-01

Full Text Available We present an AdS black hole solution with Ricci flat horizon in Einstein-phantom scalar theory. The phantom scalar fields just depend on the transverse coordinates x and y, which are parameterized by the parameter α. We study the thermodynamics of the AdS phantom black hole. Although its horizon is a Ricci flat Euclidean space, we find that the thermodynamical properties of the black hole solution are qualitatively the same as those of AdS Schwarzschild black hole. Namely, there exists a minimal temperature and the large black hole is thermodynamically stable, while the smaller one is unstable, so there is a so-called Hawking-Page phase transition between the large black hole and the thermal gas solution in the AdS space-time in Poincare coordinates. We also calculate the entanglement entropy for a strip geometry dual to the AdS phantom black holes and find that the behavior of the entanglement entropy is qualitatively the same as that of the black hole thermodynamical entropy.

Contrasting patterns of survival and dispersal in multiple habitats reveal an ecological trap in a food-caching bird.

Science.gov (United States)

Norris, D Ryan; Flockhart, D T Tyler; Strickland, Dan

2013-11-01

A comprehensive understanding of how natural and anthropogenic variation in habitat influences populations requires long-term information on how such variation affects survival and dispersal throughout the annual cycle. Gray jays Perisoreus canadensis are widespread boreal resident passerines that use cached food to survive over the winter and to begin breeding during the late winter. Using multistate capture-recapture analysis, we examined apparent survival and dispersal in relation to habitat quality in a gray jay population over 34 years (1977-2010). Prior evidence suggests that natural variation in habitat quality is driven by the proportion of conifers on territories because of their superior ability to preserve cached food. Although neither adults (>1 year) nor juveniles (conifer territories, both age classes were less likely to leave high-conifer territories and, when they did move, were more likely to disperse to high-conifer territories. In contrast, survival rates were lower on territories that were adjacent to a major highway compared to territories that did not border the highway but there was no evidence for directional dispersal towards or away from highway territories. Our results support the notion that natural variation in habitat quality is driven by the proportion of coniferous trees on territories and provide the first evidence that high-mortality highway habitats can act as an equal-preference ecological trap for birds. Reproductive success, as shown in a previous study, but not survival, is sensitive to natural variation in habitat quality, suggesting that gray jays, despite living in harsh winter conditions, likely favor the allocation of limited resources towards self-maintenance over reproduction.

Evaluation of a Professional Practice Model in the Ambulatory Care Setting

Science.gov (United States)

2014-03-10

Transforming the workplace . [executive summary]. Retrieved August 2009 from www.nap.edu/catalog/10851.html Jennings, B. (2008). Turbulence. In...quality/safety engagement. Journal of Nursing Administration, 39(4), 198-195. Ricci, P. (2012). Pregnancy project: impact of ultrasound use during... pregnancy . Third Annual Undergraduate Research Conference on Health and Society. Digital Commons@Providence. Available at: http

The anisotropic cosmological models in f ( R , T ) gravity with Λ

Indian Academy of Sciences (India)

The general class of anisotropic Bianchi cosmological models in f ( R , T ) modified theories of gravity with Λ ( T ) has been considered. This paper deals with f ( R , T ) modified theories of gravity, where the gravitational Lagrangian is given by an arbitrary function of Ricci scalar R and the trace of the stress-energy tensor T ...

Quantum energy-momentum tensor in space-time with time-like killing vector

International Nuclear Information System (INIS)

Frolov, V.P.; Zel'nikov, A.I.

1987-01-01

An approximate expression for the vacuum and thermal average μν > ren of the stress-energy tensor of conformal massless fields in static Ricci-flat space-times is constructed. The application of this approximation to the space-time of a Schwarzschild black hole and its relation to the Page-Brown-Ottewill approximation are briefly discussed. (orig.)

An Overview of Various Occurrences of General Expressions for the Coefficients of Lovelock Lagrangians and for Lovelock Tensors from the 0th to the 5th Order in Curvature

CERN Document Server

Briggs, C C

2000-01-01

An overview is given of various occurrences of general expressions for the coefficients of Lovelock Lagrangians and for Lovelock tensors from the 0th to the 5th order in curvature in terms of the Riemann-Christoffel and Ricci curvature tensors and the Riemann curvature scalar for n-dimensional differentiable manifolds having a general linear connection.

Breeding ecology of the Iranian ground jay (Podoces pleskei)

African Journals Online (AJOL)

Yomi

2011-05-23

May 23, 2011 ... located between Marvast region and Yazd city in the vicinity of. Mehriz protected .... indirect field observation using a micro video camera, TV card, PC ... med from sunrise to sunset on days in which the weather was suitable.

Introduction to special issue: Robert Jay Kastenbaum (1932-2013).

Science.gov (United States)

Fulton, Robert; Klass, Dennis; Doka, Kenneth J; Kastenbaum, Beatrice

The three pieces in this section introduce the Festschrift celebrating the works and influence of Omega: Journal of Death and Dying's founding editor, Robert Kastenbaum. Robert Fulton, an early Associate Editor of the Journal begins with some personal reflections on Kastenbaum. Klass and Doka then describe the nature of the Festschrift. A closing coda by Robert Kastenbaum's wife, Beatrice Kastenbaum, reminds us of the person behind the work.

Microsofti sõda Googleþi vastu / Jay Greene

Index Scriptorium Estoniae

Greene, Jay

2008-01-01

Microsofti konkurentsist Googleþiga, ettevõtte uuest strateegiast saavutada ülekaal internetireklaamiturul. Graafik. Lisad: Microsofti reklaamiimperatiiv; Veebireklaami turg; Tarkvara kolib veebi; Google'i eduseis; Reklaamimaht kasvab

Breeding ecology of the Iranian ground jay ( Podoces pleskei ...

African Journals Online (AJOL)

Although Podoces pleskei is the only endemic bird of Iran, little information exists on its ecological features, population dynamics and threats that concern it. This species occurs in desert and semi desert areas, mostly on the Iranian plateau, though its range spreads southeast ward to the Iran- Pakistan border.

75 FR 77651 - Endangered and Threatened Wildlife and Plants; Receipt of Application for Incidental Take Permit...

Science.gov (United States)

2010-12-13

... number TE176788-0. U.S. mail: Field Supervisor, Jacksonville Ecological Services Field Office, Attn... of occupied Florida scrub-jay foraging and sheltering habitat incidental to construction of an..., Volusia County, Florida. The project includes construction of an expansion to the existing YMCA facility...

Artificial Intelligence (Al) Center of Excellence at the University of Pennsylvania

Science.gov (United States)

1995-07-01

of C- callable routines has also been created and this enables the fabrication of more complex systems which require a high level of interaction...Micheal Hollick (locomotion play- back control), Bond -Jay Ting (body sculpting), Fran- cisco Azoula (body sculptin, anthropometry), Pei-Hwa Ho

Bond paroodiana ja iseendana / Lauri Jürisoo

Index Scriptorium Estoniae

Jürisoo, Lauri, 1980-

1998-01-01

Mängufilmid "007 ja igavene homne" ("Tomorrow Never Dies"), režissöör Roger Spottiswoode : USA 1997 ja "Austin Powers - superagent sügavkülmast" ("Austin Powers : International Man of Mystery"), režissöör Jay Roach : USA 1997

Refinements to calandria tube - liquid injection nozzle (CT-LIN) contact assessments

International Nuclear Information System (INIS)

Sedran, P.J.

2012-01-01

In recent years, the issue of CT-LIN contact, which first gained attention in 1989, has been addressed through CT-LIN gap measurements, followed by analytical predictions of time-to-contact. CT-LIN time-to-contact predictions have been preformed independently by CPUS Limited for Point Lepreau and Gentilly-2 and by AECL Sheridan Park (now Candu Energy Inc.) for Bruce Power and Gentilly-2. Both companies used the CDEPTH code in combination with CT-LIN gap measurements. Subsequent to the assessments for Point Lepreau and Gentilly-2, a recommended approach for future assessments was presented at the 2008 CANDU maintenance conference. Since that time, a number of refinements to the overall strategy for predicting CT-LIN time-to-contact have been developed and are outlined in this paper. The refinements include: 1. The use of ultrasonic LIN elevation measurements to confirm LIN creep sag behaviour 2. The development of a non-linear empirical CT Creep Sag Model 3. The development of a rationale for discrepancies observed in repeated optical CT-LIN gap measurements and a discussion of alternative CT-LIN gap measurements With these refinements, more accurate CT-LIN time-to-contact predictions can be obtained. For stations that plan to refurbish by 210,000 EFPH, the improvement in time-to-contact predictions resulting from the fore mentioned refinements will not be of any real benefit.. However, for stations that are planning life extensions in order to operate beyond 210,000 EFPH, CT-LIN contact will be an issue. For these stations, improvements in CT-LIN contact time predictions would be beneficial. This paper presents a summary of the proposed refinements and demonstrates how they would impact CT-LIN time-to-contact predictions. (author)

Plans to adapt Point Lepreau ageing management to new industry guidelines

International Nuclear Information System (INIS)

Greenlaw, G.; Gendron, T.; Slade, J.; Rankin, B.

2008-01-01

In preparation for PLGS life extension, NBPN spent considerable effort to evaluate the impact of ageing and to develop ageing management processes to maintain the required safety functions for extended operation. These were based on INPO AP-913. Recently, the CNSC has been developing Canadian ageing management guidelines in line with the IAEA approach. In response, NBPN plans to document how current PLGS processes meet the new CNSC guidelines and to identify any areas for improvement. Best practices from utilities that have retrofitted IAEA guidelines and PLGS experience in applying risk-based methods for ageing management will be used to implement improvements. (author)

Implementation of Canflex bundle manufacture - from 'bench scale' to production

International Nuclear Information System (INIS)

Pant, A.

1999-01-01

Zircatec Precision Industries (ZPI) has been involved with the development of the 43 element Canflex bundle design since 1986. This development included several 'prototype' campaigns involving the manufacture of small quantities of test bundles using enriched fuel. Manufacturing and inspection methods for this fuel were developed at ZPI as the design progressed. The most recent campaign involved the production of 26 bundles of the final Canflex design for a demonstration irradiation in the Point Lepreau Generating Station. This presentation will explore issues pertaining to the introduction of a new product line from initial trial quantities to full production levels. The Canflex fuel experience and a brief review of development efforts will be used as an example. (author)

Development and implementation of a construction environmental protection program at a solid radioactive waste management facility

Energy Technology Data Exchange (ETDEWEB)

Wong, T.S. [Atomic Energy of Canada Limited, Mississauga, Ontario (Canada); Bishop, T. [Atomic Energy of Canada Limited, Saint John, New Brunswick (Canada); Hickman, C.N. [Point Lepreau Generating Station, Saint John, New Brunswick (Canada)

2007-07-01

Refurbishment of ageing nuclear stations has great economic and environmental benefits, including reduced greenhouse gas emissions. The Government of New Brunswick (NB) decided in 2005 to refurbish the Point Lepreau Generating Station with Atomic Energy of Canada Limited (AECL) as the general contractor. The project includes construction of additional radioactive waste management facilities. AECL developed, for the construction project, an environmental protection program to comply with commitments made during the environmental assessment process, and regulatory requirements. The program covers detailed environmental plans, training courses, and engagement of consultants to provide training and conduct monitoring of the construction activities. Construction related environmental effects have been successfully mitigated and the monitoring results indicate compliance with all environmental requirements. (author)

Life's Little Joke

Indian Academy of Sciences (India)

Stephen Jay Gould wrote extensively and ... I). gun is formidable enough against an obsidian blade, but ... Several times during this history, different branches migrated to Europe, where ... the eminent paleontologist Othniel C Marsh. ... captures pictorially the most common of all misconceptions about the shape and pattern.

A Comparison of the DISASTER (Trademark) Scheduling Software with a Simultaneous Scheduling Algorithm for Minimizing Maximum Tardiness in Job Shops

Science.gov (United States)

1993-09-01

goal ( Heizer , Render , and Stair, 1993:94). Integer Prgronmming. Integer programming is a general purpose approach used to optimally solve job shop...Scheduling," Operations Research Journal. 29, No 4: 646-667 (July-August 1981). Heizer , Jay, Barry Render and Ralph M. Stair, Jr. Production and Operations

A Comparative Study between U.S. and Brazilian Acquisition Regulations and Practices

Science.gov (United States)

2011-03-01

to describe continuous improvements efforts ( Render and Heizer , 2008). Caddick and Dale (1998) on their paper ‘The impact of quality management on...2002). Outsourcing in Edinburgh and the Lothians. European Journal of Purchasing and Supply Chain Management 8 (2) 83-95. Render , Barry; Heizer , Jay

Nigerian Journal of Clinical Practice - Vol 11, No 1 (2008)

African Journals Online (AJOL)

Pattern of non-communicable diseases among medical admissions in Port Harcourt, Nigeria. EMAIL FREE FULL TEXT ... Pattern Of dyslipidaemia among Nigerians with type 2 diabetes mellitus · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT ... JO Eigbefoh, PS Mabayoje, JAY Aliyu, 86-88 ...

Negotiating Vision: Listening with the Eyes and Hearing Landscape ...

African Journals Online (AJOL)

This article uses the idea of landscape as a heterodox tactic to enable discursive intersections between musical thought, land, colonialism and spectatorial epistemologies. It begins with a brief consideration of Cartesian perspectivalism and baroque vision as two dominant scopic regimes of modernity (Jay 1988), before ...

Öö täis õuduseid / Signe Sillasoo

Index Scriptorium Estoniae

Sillasoo, Signe

2009-01-01

PÖFFi ja Tudengipäevade öiste filmiseansside sarja esimesest filmiööst Night Of the Movie Eaters 21. aprillil kinos Sõprus, mil kavas kolm õudusfilmi : Mark ja Jay Duplass' "Kottpea" (USA, 2008), Patrik Syverseni "Inimjaht" (Norra, 2008), Yoshihiro Nishimura "Tokyo Gore Police" (Jaapan, 2008)

The Nordic Trade Union Movement and Transnational Anti-Communist Networks in the Early Cold War

DEFF Research Database (Denmark)

Knudsen, Dino

2014-01-01

Dino Knudsen investigates how the American trade union movement, including figures such as Jay Lovestone and Irving Brown, established anti-Communist networks among the Nordic Non-Communist Left during the early Cold War. What were the implications of these networks, in the context of the Marshall...

Book Reviews | Whiffler | African Zoology

African Journals Online (AJOL)

Book Reviews. Lynne Whiffler, S.G. Compton, M.R. Perrin, M.D. Picker, M.R. Perrin, P.C. Magnuson, Jay O'Keefe, A.N. Hodgson, P Hewitt, S Endrödy-Younga, L.G. Underhill, H.M. Dott, R.T.F. Bernard, C.R. Brown ...

Neutral signature Walker-VSI metrics

International Nuclear Information System (INIS)

Coley, A; McNutt, D; Musoke, N; Brooks, D; Hervik, S

2014-01-01

We will construct explicit examples of four-dimensional neutral signature Walker (but not necessarily degenerate Kundt) spaces for which all of the polynomial scalar curvature invariants vanish. We then investigate the properties of some particular subclasses of Ricci flat spaces. We also briefly describe some four-dimensional neutral signature Einstein spaces for which all of the polynomial scalar curvature invariants are constant. (paper)

Calabi–Yau metrics and string compactification

Directory of Open Access Journals (Sweden)

Michael R. Douglas

2015-09-01

Full Text Available Yau proved an existence theorem for Ricci-flat Kähler metrics in the 1970s, but we still have no closed form expressions for them. Nevertheless there are several ways to get approximate expressions, both numerical and analytical. We survey some of this work and explain how it can be used to obtain physical predictions from superstring theory.

Fulltext PDF

Indian Academy of Sciences (India)

Perelman decided to work alone. In an unorthodox way, on November 11,2002, Perelman posted a thirty nine page paper with ground breaking results on the Ricci flow and its singularities on arXiv.org, a web site used to post preprint articles. By casually posting a proof on the internet of one of the most famous problems in ...

Painlev\\'e analysis of the Bryant Soliton

OpenAIRE

de la Parra, Alejandro Betancourt

2013-01-01

We carry out a Painlev\\'e analysis of the systems of differential equations corresponding to the steady and the expanding, rotationally symmetric, gradient Ricci solitons on $\\mathbb{R}^n$. For the steady case, dimensions of the form $n=k^2+1$ are singled out, with dimensions 2, 5, and 10 being particularly distinguished. Only dimension 2 is singled out for the expanding soliton.

A General Expression for the Quartic Lovelock Tensor

OpenAIRE

Briggs, C. C.

1997-01-01

A general expression is given for the quartic Lovelock tensor in terms of the Riemann-Christoffel and Ricci curvature tensors and the Riemann curvature scalar for n-dimensional differentiable manifolds having a general linear connection. In addition, expressions are given (in the appendix) for the coefficient of the quartic Lovelock Lagrangian as well as for lower-order Lovelock tensors and Lovelock Lagrangian coefficients.

Journal of Biosciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Prashant K Pandey1 Jay Siddharth1 Pankaj Verma1 Ashish Bavdekar2 Milind S Patole1 Yogesh S Shouche1. Insect Molecular Biology Unit, National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411 007, Maharashtra, India; Gastroenterology Unit, Department of P ediatrics, KEM Hospital, Rasta ...

Journal of Biosciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Biosciences. Pankaj Verma. Articles written in Journal of Biosciences. Volume 37 Issue 2 June 2012 pp 221-226 Brief communication. Molecular typing of fecal eukaryotic microbiota of human infants and their respective mothers · Prashant K Pandey Jay Siddharth Pankaj Verma Ashish Bavdekar ...

Call mimicry by eastern towhees and its significance in relation to auditory learning

Science.gov (United States)

Jon S. Greenlaw; Clifford E. Shackelford; Raymond E. Brown

1998-01-01

The authors document cases of eastern towhees (Pipilo erythrophthalmus) using mimicked alarm calls from three presumptive models (blue jay (Cyanocitta cristata), brown thrasher (Toxostoma rufum), and American robin (Turdus migratorius)). In four instances, male towhees employed heterospecific calls without substitution in their own call repertoires. Three birds (New...

Sectoral Patterns of Eco-innovation

DEFF Research Database (Denmark)

Faria, Lourenco

There goes almost thirty years since the World Commission on Environment and Development released the Our Common Future report, more than four decades since the Jay W. Forrester’s Institute at MIT launched Limits to Growth, and more than two centuries since Thomas Malthus first published An Essay...

78 FR 8576 - Endangered and Threatened Wildlife and Plants; 5-Year Status Reviews of Ocelot and Mexican...

Science.gov (United States)

2013-02-06

...-- Headquarters, [email protected] Attention 5-Year (email). Review, 3325 Green Jay Road, Alamo, TX 78516. [email protected]go Arizona v (email). Ecological Services Field Office, Attention 5-Year Review, 2321 West..., during normal business hours at the offices where the comments are submitted. Completed and Active...

75 FR 14572 - Notice of Petitions by Firms for Determination of Eligibility To Apply for Trade Adjustment...

Science.gov (United States)

2010-03-26

... Filter equipment for edible oils. Sheet 9, Dover, NH 03820. metal parts of stainless steel are formed and...-Standards), and perimeter hardware. Jay Industries, Inc 150 E. Longview, 3/9/2010 Seating frames and other.../2010 Custom aluminum casting for heavy Worth, TX 76110. industry. Consumer Interstate Corporation 2...

75 FR 13264 - Meeting of the Board of Advisors (BOA) to the President, Naval Postgraduate School (NPS)

Science.gov (United States)

2010-03-19

... DEPARTMENT OF DEFENSE Department of the Navy Meeting of the Board of Advisors (BOA) to the President, Naval Postgraduate School (NPS) AGENCY: Department of the Navy, DoD. ACTION: Notice of open... access, information, or to send written comments regarding the NPS BOA, contact Ms. Jaye Panza, Naval...

Strategic Landpower and a Resurgent Russia: An Operational Approach to Deterrence

Science.gov (United States)

2016-05-01

Nicholas Burns, Dan Byman, James Jay Carafano, Phillip Carter, Wendy Chamberlin, Michael Cher- toff, Frank Cilluffo, James Clad, Richard Clarke...U.S. Army War College, Carlisle Barracks, PA, April 8, 2015. 112 46. Ibid. 47. Michelle Tan , “Army looks to rotating and reserve forc- es for Europe

Temperature dependence of electron concentration in cadmium arsenide

NARCIS (Netherlands)

Gelten, M.J.; Blom, F.A.P.

1979-01-01

From measurements of the temperature dependence of the electron concentration in Cd 3 As 2 , we found values for the conduction-band parameters that are in good agreement with those recently reported by Aubin, Caron, and Jay-Gerin. However, in contrast with these authors we found no small overlap,

Pop / Koit Raudsepp

Index Scriptorium Estoniae

Raudsepp, Koit

2001-01-01

Heliplaatidest: S. I. Futures "The Mission Statement". Lilac Time "Compendium - The Fontana Trinity". Jeff Buckley "Live A L'Olympia". The Confusion Musical Academy Presents: Irmin Schmidt & Kumo "Masters of Confusion". Kylie "Fever. Jay-Z "The Blueprint". The Crash "Wildlife". Ben Folds "Rockin' The Suburbs". Daft Punk "Alive 1997"

Adaptive Mesh Refinement and High Order Geometrical Moment Method for the Simulation of Polydisperse Evaporating Sprays

Directory of Open Access Journals (Sweden)

Essadki Mohamed

2016-09-01

Full Text Available Predictive simulation of liquid fuel injection in automotive engines has become a major challenge for science and applications. The key issue in order to properly predict various combustion regimes and pollutant formation is to accurately describe the interaction between the carrier gaseous phase and the polydisperse evaporating spray produced through atomization. For this purpose, we rely on the EMSM (Eulerian Multi-Size Moment Eulerian polydisperse model. It is based on a high order moment method in size, with a maximization of entropy technique in order to provide a smooth reconstruction of the distribution, derived from a Williams-Boltzmann mesoscopic model under the monokinetic assumption [O. Emre (2014 PhD Thesis, École Centrale Paris; O. Emre, R.O. Fox, M. Massot, S. Chaisemartin, S. Jay, F. Laurent (2014 Flow, Turbulence and Combustion 93, 689-722; O. Emre, D. Kah, S. Jay, Q.-H. Tran, A. Velghe, S. de Chaisemartin, F. Laurent, M. Massot (2015 Atomization Sprays 25, 189-254; D. Kah, F. Laurent, M. Massot, S. Jay (2012 J. Comput. Phys. 231, 394-422; D. Kah, O. Emre, Q.-H. Tran, S. de Chaisemartin, S. Jay, F. Laurent, M. Massot (2015 Int. J. Multiphase Flows 71, 38-65; A. Vié, F. Laurent, M. Massot (2013 J. Comp. Phys. 237, 277-310]. The present contribution relies on a major extension of this model [M. Essadki, S. de Chaisemartin, F. Laurent, A. Larat, M. Massot (2016 Submitted to SIAM J. Appl. Math.], with the aim of building a unified approach and coupling with a separated phases model describing the dynamics and atomization of the interface near the injector. The novelty is to be found in terms of modeling, numerical schemes and implementation. A new high order moment approach is introduced using fractional moments in surface, which can be related to geometrical quantities of the gas-liquid interface. We also provide a novel algorithm for an accurate resolution of the evaporation. Adaptive mesh refinement properly scaling on massively

Cosmology of non-minimal derivative coupling to gravity in Palatini formalism and its chaotic inflation

Science.gov (United States)

Kaewkhao, Narakorn; Gumjudpai, Burin

2018-06-01

We consider, in Palatini formalism, a modified gravity of which the scalar field derivative couples to Einstein tensor. In this scenario, Ricci scalar, Ricci tensor and Einstein tensor are functions of connection field. As a result, the connection field gives rise to relation, hμν = fgμν between effective metric, hμν and the usual metric gμν where f = 1 - κϕ,αϕ,α / 2. In FLRW universe, NMDC coupling constant is limited in a range of - 2 /ϕ˙2 - 1 / 3. Power-law potentials of chaotic inflation are considered. For V ∝ϕ2 and V ∝ϕ4, it is possible to obtain tensor-to-scalar ratio lower than that of GR so that it satisfies r < 0 . 12 as constrained by Planck 2015 (Ade et al., 2016). The V ∝ϕ2 case yields acceptable range of spectrum index and r values. The quartic potential's spectrum index is disfavored by the Planck results. Viable range of κ for V ∝ϕ2 case lies in positive region, resulting in less blackhole's entropy, superluminal metric, more amount of inflation, avoidance of super-Planckian field initial value and stronger gravitational constant.

Conformal coupling of gravitational wave field to curvature

International Nuclear Information System (INIS)

Grishchuk, L.P.; Yudin, V.

1980-01-01

Conformal properties of the equations for weak gravitational waves in a curved space--time are investigated. The basic equations are derived in the linear approximation from Einstein's equations. They represent, in fact, the equations for the second-rank tensor field h/sub alphabeta/, restricted by the auxiliary conditions h/sub α//sup β//sub ;/α =0, hequivalentγ/sub alphabeta/h/sup alphabeta/=0, and embedded into the background space--time with the metric tensor γ/sub alphabeta/. It is shown that the equations for h/sub alphabeta/ are not conformally invariant under the transformations gamma-circumflex/sub alphabeta/ =e/sup 2sigma/γ/sub alphabeta/ and h/sub alphabeta/ =e/sup sigma/h/sub alphabeta/, except for those metric rescalings which transform the Ricci scalar R of the original background space--time into e/sup -2sigma/R, where R is the Ricci scalar of the conformally related background space--time. The general form of the equations for h/sub alphabeta/ which are conformally invariant have been deduced. It is shown that these equations cannot be derived in the linear approximation from any tensor equations which generalize the Einstein equations

Nõela all : Igakuine vinüülitutvustus / Stony Place

Index Scriptorium Estoniae

Stony Place

1998-01-01

Uutest vinüülplaatidest Daddy's Favourite "I Feel Good Things For You", Kenny Lattimore "Days Like This", 70̀ s Age "Reach For The Sky","Grindlocked EP", Bill Riley "Closing In EP", Moodymann "Forevernevermore", Frankie Valentine "Staring In The face Of Extinction", "Norman Jay presents Philadelphia" International 1973-81"

Fulltext PDF

Indian Academy of Sciences (India)

PRAKASH KUMAR

materials, but we might well need to make different selections ... no consideration of shape, and structural stiffnesses depend intrinsically on size. ... area runs parallel to the force. As angular ..... that hold leaf blades extended from branches, should at the ... jay (Cyanocitta cristata); (c) neural spine of an unidentified bony fish.

Twenty-Five year (1982-2007) history of lodgepole pine dwarf mistletoe animal vectors and ethephon control on the Fraser Experimental Forest in Colorado

Science.gov (United States)

Thomas. Nicholls

2009-01-01

This is a summary of the 25-year history of studies of mammal and bird vectors of lodgepole pine dwarf mistletoe (Arceuthobium americanum), ethephon control of dwarf mistletoe, and the ecology of the most important dwarf mistletoe vector, the gray jay (Persisoreus canadensis), on the USDA Forest Service, Fraser Experimental Forest...

Experimental Evaluations of Selected Immersion Hypothermia Protection Equipment.

Science.gov (United States)

1979-10-12

the research were Jim Strawhorn, Tom Horseman and Jay Smith. ii Srb "Peeat~loj 0",___e_____._______ . TABLE OF CONTENTS EXPERIMENTAL EVALUATIONS OF...In death . Insulating the body will decrease the amount of heat removed. The thickness of an Insulation layer and the type of material from which it is

I snova pro ljubov... k paukam i politseiskim / Jevgeni Levik

Index Scriptorium Estoniae

Levik, Jevgeni

2002-01-01

Prantsuse mängufilm "Armastab, ei armasta" ("A la folie...pas du tout") : režissöör Laetitia Colombani ja kaks ameerika mängufilmi - "Super Troopers" : režissöör Jay Chandrasekhar ning "Van Wilder : Party Liaison" : režissöör Walt Becker

The transdisciplinary potential of remediated painting

DEFF Research Database (Denmark)

Petersen, Anne Ring

2011-01-01

painting as a point of departure but moves beyond the limitations of dialogic intermedia into the field of transdisciplinary aesthetics. In support of my argument, I turn to the concept of remediation as it was first applied in new media theory by Jay David Bolter and Richard Grusin. The ambition...

Development of the Young Brain

Medline Plus

Full Text Available ... Training (1 item) Other Treatments (15 items) Alzheimer’s Disease (2 items) Coping with Traumatic Events (3 items) Institute Announcements (24 items) Development of the Young Brain May 2, 2011 For more than twenty years, National Institute of Mental Health neuroscientist Dr. Jay Giedd has studied the ...

Ralph Spaccatutto, ovvero il videogioco come repertorio culturale del cinema

Directory of Open Access Journals (Sweden)

Marco Teti

2013-03-01

Full Text Available L'articolo mette il film d'animazione "Ralph Spaccatutto" in relazione all'universo estetico e iconografico del videogioco. L'analisi viene fondata sulla nozione di 'repertorio culturale', che riprende i concetti di rimediazione e di convergenza culturale elaborati da Jay David Bolter, Richard Grusin e Henry Jenkins.

Time evolution in a geometric model of a particle

International Nuclear Information System (INIS)

Atiyah, M.F.; Franchetti, G.; Schroers, B.J.

2015-01-01

We analyse the properties of a (4+1)-dimensional Ricci-flat spacetime which may be viewed as an evolving Taub-NUT geometry, and give exact solutions of the Maxwell and gauged Dirac equation on this background. We interpret these solutions in terms of a geometric model of the electron and its spin, and discuss links between the resulting picture and Dirac’s Large Number Hypothesis.

On Riemannian manifolds (Mn, g) of quasi-constant curvature

International Nuclear Information System (INIS)

Rahman, M.S.

1995-07-01

A Riemannian manifold (M n , g) of quasi-constant curvature is defined. It is shown that an (M n , g) in association with other class of manifolds gives rise, under certain conditions, to a manifold of quasi-constant curvature. Some observations on how a manifold of quasi-constant curvature accounts for a pseudo Ricci-symmetric manifold and quasi-umbilical hypersurface are made. (author). 10 refs

Hypersurfaces in simply connected space forms

Indian Academy of Sciences (India)

Let M be a hypersurface of (M(κ), ds2). For every point m ∈ M, let A: TmM → TmM be the Weingarten map of the hypersurface. In this paper we prove the following results. Theorem 1. Let M be a connected hypersurface in the simply connected space form. (M(κ), ds2) such that the Ricci curvature of M satisfies the inequality ...

Vacuum spacetimes with a spacelike, hypersurface-orthogonal Killing vector: reduced equations in a canonical frame

International Nuclear Information System (INIS)

Bonanos, S

2003-01-01

The Newman-Penrose equations for spacetimes having one spacelike Killing vector are reduced-in a geometrically defined 'canonical frame' - to a minimal set, and its differential structure is studied. Expressions for the frame vectors in an arbitrary coordinate basis are given, and coordinate-independent choices of the metric functions are suggested which make the components of the Ricci tensor in the direction of the Killing vector vanish

From Passive to Active Listening: "Lullaby of Clubland" by Everything but the Girl, Part 2

Science.gov (United States)

Reynolds, Geoffrey A.

2010-01-01

In the first part of this two-part article, the author described Dr. Patricia Shehan Campbell's (2004) exciting ideas for fully engaging students during listening lessons. He chose Everything But the Girl's song "Lullaby Of Clubland the Jay "Sinister" Sealee Remix" to model Dr. Campbell's pedagogical sequence. He also described the three-stage…

From Passive to Active Listening: "Lullaby of Clubland" by Everything but the Girl, Part 1

Science.gov (United States)

Reynolds, Geoffrey A.

2010-01-01

This two-part article revisits the British group Everything But the Girl. In this first part, the author describes Dr. Patricia Shehan Campbell's (2004) exciting ideas for fully engaging students during listening lessons. The author uses Everything But the Girl's song "Lullaby Of Clubland (Jay "Sinister" Sealee Remix)" to model Dr. Campbell's…

Going Greek: Academics, Personal Change, and Life after College

Science.gov (United States)

Routon, Wesley; Walker, Jay

2016-01-01

Social Greek-letter organizations, more commonly known as fraternities (male-only) and sororities (female-only), are a longstanding tradition at colleges and universities in the United States. They claim to instill leadership skills in and offer a support network for members. However, in this article Wesley Routon and Jay Walker state that…

Insurance: Profitability of the Medical Malpractice and General Liability Lines. Report to Congressional Requesters.

Science.gov (United States)

General Accounting Office, Washington, DC.

This report on the profitability of the property/casualty insurance industry and in particular of the medical malpractice insurance line was prepared at the request of Representatives Henry A. Waxman and James J. Florio and Senators Paul Simon, Daniel K. Inouye, Albert Gore, Jr., and Jay D. Rockefeller. Four different estimates of medical…

Journal Use by Graduate Students as Indicated by Master's Theses Bibliographies at an Urban Commuter College, 1991-2004

Science.gov (United States)

Sexton, Ellen

2006-01-01

Citation analyses were carried out on master's theses in three disciplines: forensic psychology, forensic science, and criminal justice, completed and deposited in the John Jay College Library from 1991 to 2004. The aim was to determine the effect of availability of electronic journals on students' choice of references. The number of journal…

The Transdisciplinary Potential of Remediated Painting

DEFF Research Database (Denmark)

Petersen, Anne Ring

2010-01-01

the limitations of dialogic intermedia into the field of transdisciplinary aesthetics. In support of my argument, I turn to the concept of remediation as it was first applied in new media theory by Jay David Bolter and Richard Grusin. The ambition is to develop an apprehension of painting not as an artistic...

Reconceptualising "Identity Slippage": Additional Language Learning and (L2) Identity Development

Science.gov (United States)

Armour, William

2009-01-01

This paper reconsiders the theoretical concept of "identity slippage" by considering a detailed exegesis of three model conversations taught to learners of Japanese as an additional language. To inform my analysis of these conversations and how they contribute to identity slippage, I have used the work of the systemic-functional linguist Jay Lemke…

Crafting a Teaching Persona

Science.gov (United States)

Lang, James M.

2007-01-01

In this article, the author contemplates two books dealing with developing a teaching persona. These books are Elaine Showalter's "Teaching Literature" and Jay Parini's "The Art of Teaching". Showalter and Parini present very different perspectives on the issue. Showalter addresses it in a section called "Personae: The Teaching Self," in which she…

Report to the Legislature: Child Welfare and Early Learning Partnerships

Science.gov (United States)

Washington State Department of Early Learning, 2015

2015-01-01

House Bill 2519, sponsored by Representative Tana Senn, was passed during the 2014 legislative session and signed into law by Governor Jay Inslee. HB 2519 directs the Department of Early Learning (DEL) and the Department of Social and Health Services (DSHS) to jointly develop recommendations on methods to "better partner to ensure children…

Arms Transfers: A System Dynamics Analysis Focusing on Regional Stability.

Science.gov (United States)

1983-12-01

data held by massive digital computers, nor ever !n the sophisticated and sDecia!; zec ;r%.dustral roots on an as ernbl/ line, but rather in the human...Stephanie G. Neuman and Robert E. Harkavy. New York: Praeger Publishers, 1980. 10. Forrester, Jay W. and Peter M. Senge. ’Tests For Building Confi

The generation of calandria tube (CT) inner diameter profiles from fuel channel (FC) inspection data

Energy Technology Data Exchange (ETDEWEB)

Sedran, P.J., E-mail: paul.sedran@amec.com [AMEC NSS, Toronto, ON (Canada); Rankin, B., E-mail: brankin@nbpower.com [NB Power, Fredericton, NB (Canada); Lemire, C., E-mail: Lemire.Christian@hydro.qc.ca [Hydro-Quebec, Montreal, QC (Canada)

2015-07-01

Studies of CT deformation at spacer locations, key to the development of FC deformation modelling, have been limited by the availability of gauging measurements from removed CTs. In [1], it was proposed that CT dimensional profiles could be generated using FC inspection data. Since then, the concept was investigated further by assessing: (1) the normalisation of gap measurements to the diameter of the spacer coil, (2) the validity of gap measurements from inspections of Point Lepreau and Gentilly-2, and the CT dimensional profiles generated from the inspection data.It was concluded, from the work presented in this paper, that the CT-PT gap data and the CT dimensional profiles generated using the data from the two subject inspections are reasonable. (author)

Results of fuel management at Embalse nuclear power plant. Analysis of performance at other plants

International Nuclear Information System (INIS)

Paz, A.O. de; Moreno, C.A.; Vinez, J.C.

1987-01-01

The operating experience of fuel management at the Embalse nuclear power plant from new core to the present situation (approximately 937 days at full power) is described. The average core burnup is about 4000 MW d/t U and the monthly averaged discharge burnup about 7800 MW d/t U. The neutron flux distribution is calculated by means of program PUMA-C, which is periodically checked by comparison between calculated and measured values of 102 vanadium detectors. A comparison of the performance of other reactors type CANDU 600 (Point Lepreau, Gentilly 2, Wolsung) from the point of view of fuel strategy is also presented. The data to perform the comparison were obtained by means of the CANDU system of information exchange between users (COG). (Author)

Darwin's Revolution in Thought: An Illustrated Lecture. Teaching Guide and Videotape.

Science.gov (United States)

Gould, Stephen Jay

"Darwin's Revolution in Thought" is Stephen Jay Gould's definitive treatise on Charles Darwin. This 50-minute classroom edition videotaped lecture is structured in the form of a paradox and three riddles about Darwin's life. Each is designed to shed light on one of the key features of the theory of natural selection, its philosophical…

Proceedings of the Annual Meeting of the Association for Education in Journalism and Mass Communication (84th, Washington, DC, August 5-8, 2001). Media Ethics Division.

Science.gov (United States)

Association for Education in Journalism and Mass Communication.

The Media Ethics section of the proceedings contains the following 7 selected papers: "The Ethics Agenda of the Mass Communication Professorate" (Jay Black, Bruce Garrison, Fred Fedler, and Doug White); "What Would the Editor Do? A Three-Year Study of Student-Journalists and the Naming of Rape Victims in the Press" (Kim E.…

Fulltext PDF

Indian Academy of Sciences (India)

Editorial. Biman Nath, Associate Editor. Everyone has embarrassing tales to hide. One of my most embarrassing stories is that I missed a lecture by Stephen Jay Gould in New Delhi when. I was a physics undergraduate student. My knowledge of biology was. (and still is) abysmal and I didn't care much about evolution. That.

Person-Centered Management in Project Administration.

Science.gov (United States)

Caraway, James E.

The theories of several contemporary management theorists are examined in order to demonstrate that their administrative stance is that of a person-intensive approach to management. After exploring leadership theory and the positions of Douglas McGregor, John J. Morse, Jay W. Lorsch, Rensis Likert, Bernard M. Bass, William Reddin, George H. Rice,…

Genetic diversity in two populations of Limicolaria aurora (Jay, 1839 ...

African Journals Online (AJOL)

Tuoyo Aghomotsegin

2016-06-22

Jun 22, 2016 ... tissues of the foot of eight individuals from each location using cetyltrimethylammonium bromide ... but can as well be advantageous; the snail meat can be a ..... International Conference on Environmental Engineering and.

Genetic diversity in two populations of Limicolaria aurora (Jay, 1839 ...

African Journals Online (AJOL)

Limicolaria aurora belongs to the group of land snails commonly called garden snails. This study seeks to use shell morphology and random amplified polymorphic DNA-polymerase chain reaction (RAPDPCR) to examine gross morphological differences in populations of L. aurora from New Bussa (guinea savannah) and ...

Proactive conservation management of an island-endemic bird species in the face of global change

Science.gov (United States)

Morrison, S.A.; Sillett, T. Scott; Ghalambor, Cameron K.; Fitzpatrick, J.W.; Graber, D.M.; Bakker, V.J.; Bowman, R.; Collins, C.T.; Collins, P.W.; Delaney, K.S.; Doak, D.F.; Koenig, Walter D.; Laughrin, L.; Lieberman, A.A.; Marzluff, J.M.; Reynolds, M.D.; Scott, J.M.; Stallcup, J.A.; Vickers, W.; Boyce, W.M.

2011-01-01

Biodiversity conservation in an era of global change and scarce funding benefits from approaches that simultaneously solve multiple problems. Here, we discuss conservation management of the island scrub-jay (Aphelocoma insularis), the only island-endemic passerine species in the continental United States, which is currently restricted to 250-square-kilometer Santa Cruz Island, California. Although the species is not listed as threatened by state or federal agencies, its viability is nonetheless threatened on multiple fronts. We discuss management actions that could reduce extinction risk, including vaccination, captive propagation, biosecurity measures, and establishing a second free-living population on a neighboring island. Establishing a second population on Santa Rosa Island may have the added benefit of accelerating the restoration and enhancing the resilience of that island's currently highly degraded ecosystem. The proactive management framework for island scrub-jays presented here illustrates how strategies for species protection, ecosystem restoration, and adaptation to and mitigation of climate change can converge into an integrated solution. ?? 2011 by American Institute of Biological Sciences. All rights reserved.

Determining nest predators of the Least Bell's Vireo through point counts, tracking stations, and video photography

Science.gov (United States)

Peterson, Bonnie L.; Kus, Barbara E.; Deutschman, Douglas H.

2004-01-01

We compared three methods to determine nest predators of the Least Bell's Vireo (Vireo bellii pusillus) in San Diego County, California, during spring and summer 2000. Point counts and tracking stations were used to identify potential predators and video photography to document actual nest predators. Parental behavior at depredated nests was compared to that at successful nests to determine whether activity (frequency of trips to and from the nest) and singing vs. non-singing on the nest affected nest predation. Yellow-breasted Chats (Icteria virens) were the most abundant potential avian predator, followed by Western Scrub-Jays (Aphelocoma californica). Coyotes (Canis latrans) were abundant, with smaller mammalian predators occurring in low abundance. Cameras documented a 48% predation rate with scrub-jays as the major nest predators (67%), but Virginia opossums (Didelphis virginiana, 17%), gopher snakes (Pituophis melanoleucus, 8%) and Argentine ants (Linepithema humile, 8%) were also confirmed predators. Identification of potential predators from tracking stations and point counts demonstrated only moderate correspondence with actual nest predators. Parental behavior at the nest prior to depredation was not related to nest outcome.

Curvature-driven acceleration: a utopia or a reality?

International Nuclear Information System (INIS)

Das, Sudipta; Banerjee, Narayan; Dadhich, Naresh

2006-01-01

The present work shows that a combination of nonlinear contributions from the Ricci curvature in Einstein field equations can drive a late time acceleration of expansion of the universe. The transit from the decelerated to the accelerated phase of expansion takes place smoothly without having to resort to a study of asymptotic behaviour. This result emphasizes the need for thorough and critical examination of models with nonlinear contribution from the curvature

Curvature-driven acceleration: a utopia or a reality?

Energy Technology Data Exchange (ETDEWEB)

Das, Sudipta [Relativity and Cosmology Research Centre, Department of Physics, Jadavpur University, Calcutta-700 032 (India); Banerjee, Narayan [Relativity and Cosmology Research Centre, Department of Physics, Jadavpur University, Calcutta-700 032 (India); Dadhich, Naresh [Inter University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007 (India)

2006-06-21

The present work shows that a combination of nonlinear contributions from the Ricci curvature in Einstein field equations can drive a late time acceleration of expansion of the universe. The transit from the decelerated to the accelerated phase of expansion takes place smoothly without having to resort to a study of asymptotic behaviour. This result emphasizes the need for thorough and critical examination of models with nonlinear contribution from the curvature.

Untitled

Indian Academy of Sciences (India)

We denote by W A V the composition of V. V with the bundle map. T*M (3 T M & A. T. M. - A2 T M (3 AP T4 M arising from alternating of the first two factors. By Ricci identities VA Voss. Ko is an algebraic operator depending linearly on curvature tensor of M. More precisely, in terms of classical tensor notation (cf. (4), p. 130),.

Shearfree congruences of null geodesics and Killing tensors

International Nuclear Information System (INIS)

Dietz, W.; Ruediger, R.

1980-01-01

In this communication, the mutual connections between quantities that are generalizations of the notion of a a Killing vector field are investigated. A classification of these quantities in terms of a complex vector field αsub(a) is given. A common feature of all these quantities is that they imply the existence of a pair of shearfree geodetic null congruences. There are no explicit restrictions posed on the Ricci tensor. (author)

Remarks on an identity by R. Schoen and others

International Nuclear Information System (INIS)

Ezin, J.P.

1988-10-01

Using the tensor calculus it is pointed out that Schoen's identity and similar ones can be derived from a universal identity which appears as a generalization of the divergence theorem. In a new application of this identity, a necessary condition is obtained for a symmetric (0,2) tensor field to be the Ricci curvature tensor of a metric on a compact manifold with constant scalar curvature. 9 refs

On construction of two-dimensional Riemannian manifolds embedded into enveloping Euclidean (pseudo-Euclidean) space

International Nuclear Information System (INIS)

Saveliev, M.V.

1983-01-01

In the framework of the algebraic approach a construction of exactly integrable two-dimensional Riemannian manifolds embedded into enveloping Euclidean (pseudo-Euclidean) space Rsub(N) of an arbitrary dimension is presented. The construction is based on a reformulation of the Gauss, Peterson-Codazzi and Ricci equations in the form of a Lax-type representation in two-dimensional space. Here the Lax pair operators take the values in algebra SO(N)

Frailty and cardiovascular risk in community-dwelling elderly: a population-based study

OpenAIRE

Ricci NA; Pessoa GS; Ferriolli E; Dias RC; Perracini MR

2014-01-01

Natalia Aquaroni Ricci,1 Germane Silva Pessoa,1 Eduardo Ferriolli,2 Rosangela Correa Dias,3 Monica Rodrigues Perracini1 1Master’s and Doctoral Programs in Physical Therapy, Universidade Cidade de São Paulo (UNICID), São Paulo, 2Faculty of Medicine, Universidade de São Paulo (USP), Ribeirão Preto, 3Department of Physiotherapy, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil Background: Evidence suggests a possible bidir...

Irony and Vision in Selected Works of Ayi Kwei Armah | Iboroma ...

African Journals Online (AJOL)

The use of a medley of literary techniques such as irony unfolds the vision of life or society delineated by the writer in his work of art. Adopting the definitions of situational irony by Ephraim Chukwu, Xiang Li and Jay Braiman as the framework, this paper investigates Armah's manipulation of the ironic mode to convey his ...

Introduction to the Articles on Innovative Applications of Artificial Intelligence

OpenAIRE

Rychtyckyj, Nestor; Shapiro, Daniel

2011-01-01

This issue of AI Magazine provides extended versions of several papers that were recently presented at the Innovative Applications of Artificial Intelligence Conference (IAAI-2010). We present three articles reflecting deployed applications of AI, one describing a unique, emerging application, plus an article based on the invited talk by Jay M. Tenenbaum, who was the 2010 Engelmore Award recipient.

Passive Gamma-Ray Emission for Underwater Sediment-Disturbance Detection

Science.gov (United States)

2017-07-18

solutions in civil and military engineering , geospatial sciences, water resources, and environmental sciences for the Army, the Department of Defense... Engineer Research and Development Center (ERDC) solves the nation’s toughest engineering and environmental challenges. ERDC develops innovative...Sediment-Disturbance Detection Jay L. Clausen U.S. Army Engineer Research and Development Center (ERDC) Cold Regions Research and Engineering

Plaadid / Immo Mihkelson

Index Scriptorium Estoniae

Mihkelson, Immo, 1959-

2003-01-01

Uutest plaatidest Barbara Streisand "The Movie Album", paul Oakenfold "Great Wall", Van Morrison "What's Wrong With This Picture", Jay-Z "The Black Album", Roberto Di Gioia's Marrsmobil "Strange World", G Unit "Beg For Mercy", Jimi Hendrix Experience "Live At Berkeley", "Bad Boys II", Laibach "Wat", Jet "Get Born", Isley Meets Bacharach "Here I Am", Starsailor "Silence Is Easy"

Resonance – Journal of Science Education | Indian Academy of ...

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 11. Stephen Jay Gould: A View of Life. Renee M Borges. Article-in-a-Box Volume 7 Issue 11 November 2002 pp 2-5. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/007/11/0002-0005 ...

Resonance – Journal of Science Education | News

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 11. Issue front cover thumbnail Issue back cover thumbnail. Volume 7, Issue 11. November 2002, pages 1-102. pp 1-1 Editorial. Editorial · Biman Nath · More Details Fulltext PDF. pp 2-5 Article-in-a-Box. Stephen Jay Gould: A View of Life.

Inside the Adolescent Brain

Science.gov (United States)

Drury, Stacy S.

2009-01-01

Dr. Jay Giedd says that the main alterations in the adolescent brain are the inverted U-shaped developmental trajectories with late childhood/early teen peaks for gray matter volume among others. Giedd adds that the adolescent brain is vulnerable to substances that artificially modulate dopamine levels since its reward system is in a state of flux.

Genetics Home Reference: Jackson-Weiss syndrome

Science.gov (United States)

... Jabs EW, Li X, Scott AF, Meyers G, Chen W, Eccles M, Mao JI, Charnas LR, Jackson CE, Jaye M. Jackson-Weiss and Crouzon syndromes are allelic with mutations in fibroblast growth factor receptor 2. Nat Genet. 1994 Nov;8(3):275-9. Erratum in: Nat Genet 1995 Apr;9(4):451. Citation on PubMed Robin ...

On Matteo Ricci’s Interpretations of Chinese Culture

Directory of Open Access Journals (Sweden)

Chen Hong

2015-03-01

Full Text Available On the contribution to introducing Western learning to China by Matteo Ricci (1552-1610, the 16th -century Italian Jesuit missionary to the Ming Dynasty, abundant research has been done; however, not so on his contribution to introducing Chinese learning to the West, and if so, not profoundly. Though Ricci‟s understandings of Chinese culture were found in every aspect of Ming Dynasty lives, this essay focuses on four important and representative aspects, and analyzes the political system of a government guided by philosophers, the confused outlooks of religious sects, Chinese ethics compared to Christian tenets, and the unique qualities of the Chinese language. It discloses Ricci‟s moderate (middle-of-the-road attitude toward Chinese culture, especially his efforts to reconcile Confucianism and Christianity as well as his prejudice against Buddhism and Taoism, which shows on the one hand his broad-mindedness as a humanistic missionary, and on the other the historical or rather religious limitations of his absolute faith as a pious Catholic. Narrow-minded or broad-minded, Ricci‟s role as the first scholar who introduced Chinese learning to the West should not be neglected. One should bear in mind that it is Ricci who laid the foundation for European sinology.

Metrics with vanishing quantum corrections

International Nuclear Information System (INIS)

Coley, A A; Hervik, S; Gibbons, G W; Pope, C N

2008-01-01

We investigate solutions of the classical Einstein or supergravity equations that solve any set of quantum corrected Einstein equations in which the Einstein tensor plus a multiple of the metric is equated to a symmetric conserved tensor T μν (g αβ , ∂ τ g αβ , ∂ τ ∂ σ g αβ , ...,) constructed from sums of terms, the involving contractions of the metric and powers of arbitrary covariant derivatives of the curvature tensor. A classical solution, such as an Einstein metric, is called universal if, when evaluated on that Einstein metric, T μν is a multiple of the metric. A Ricci flat classical solution is called strongly universal if, when evaluated on that Ricci flat metric, T μν vanishes. It is well known that pp-waves in four spacetime dimensions are strongly universal. We focus attention on a natural generalization; Einstein metrics with holonomy Sim(n - 2) in which all scalar invariants are zero or constant. In four dimensions we demonstrate that the generalized Ghanam-Thompson metric is weakly universal and that the Goldberg-Kerr metric is strongly universal; indeed, we show that universality extends to all four-dimensional Sim(2) Einstein metrics. We also discuss generalizations to higher dimensions

The positive action conjecture and asymptotically euclidean metrics in quantum gravity

International Nuclear Information System (INIS)

Gibbons, G.W.; Pope, C.N.

1979-01-01

The positive action conjecture requires that the action of any asymptotically Euclidean 4-dimensional Riemannian metric be positive, vanishing if and only if the space is flat. Because any Ricci flat, asymptotically Euclidean metric has zero action and is local extremum of the action which is a local minimum at flat space, the conjecture requires that there are no Ricci flat asymptotically Euclidean metrics other than flat space, which would establish that flat space is the only local minimum. We prove this for metrics on R 4 and a large class of more complicated topologies and for self-dual metrics. We show that if Rsupμsubμ >= 0 there are no bound states of the Dirac equation and discuss the relevance to possible baryon non-conserving processes mediated by gravitational instantons. We conclude that these are forbidden in the lowest stationary phase approximation. We give a detailed discussion of instantons invariant under an SU(2) or SO(3) isometry group. We find all regular solutions, none of which is asymptotically Euclidean and all of which possess a further Killing vector. In an appendix we construct an approximate self-dual metric on K3 - the only simply connected compact manifold which admits a self-dual metric. (orig.) [de

Black holes in higher dimensional gravity theory with corrections quadratic in curvature

International Nuclear Information System (INIS)

Frolov, Valeri P.; Shapiro, Ilya L.

2009-01-01

Static spherically symmetric black holes are discussed in the framework of higher dimensional gravity with quadratic in curvature terms. Such terms naturally arise as a result of quantum corrections induced by quantum fields propagating in the gravitational background. We focus our attention on the correction of the form C 2 =C αβγδ C αβγδ . The Gauss-Bonnet equation in four-dimensional spacetime enables one to reduce this term in the action to the terms quadratic in the Ricci tensor and scalar curvature. As a result the Schwarzschild solution which is Ricci flat will be also a solution of the theory with the Weyl scalar C 2 correction. An important new feature of the spaces with dimension D>4 is that in the presence of the Weyl curvature-squared term a necessary solution differs from the corresponding 'classical' vacuum Tangherlini metric. This difference is related to the presence of secondary or induced hair. We explore how the Tangherlini solution is modified by 'quantum corrections', assuming that the gravitational radius r 0 is much larger than the scale of the quantum corrections. We also demonstrated that finding a general solution beyond the perturbation method can be reduced to solving a single third order ordinary differential equation (master equation).

Restructuring of Canada's nuclear utilities: recent developments

International Nuclear Information System (INIS)

Guindon, S.

1998-01-01

Business decisions relating to the electric power sector are a provincial responsibility in Canada. The federal government looks to the three nuclear utilities to manage their nuclear assets and maintain them in a way that maximizes their reliability, efficiency and overall performance. A significant development in Canada's nuclear sector in the past year was the Ontario Hydro Nuclear Asset Optimization Plan. Structural change in the North American electricity market is a major impetus for decisions regarding nuclear assets by Canada's electric power utilities. The Ontario government is now taking steps to introduce competition in the Ontario Electricity market. The province of New Brunswick, which has one reactor at Point Lepreau which supplies one-third of the province's electricity, is also taking measures to introduce competition in its electricity market. (author)

Thermosyphoning in the CANDU reactor

International Nuclear Information System (INIS)

Spinks, N.J.; Wright, A.C.D.; Caplan, M.Z.; Prawirosoehardjo, S.; Gulshani, P.

1984-01-01

Thermosyphoning is defined as the natural convective flow of primary coolant over the boilers. It is the predicted mode of heat transport from core to boilers in many postulated scenarios for CANDU reactor safety analysis. The scenarios encompass a wide range of boundary conditions in reactor power, secondary temperature and primary coolant inventory. Loss of pumping of the primary coolant is a common feature. Thermosyphoning is single or two-phase depending on the boundary conditions. The paper describes the important thermohydraulic characteristics of thermosyphoning in CANDU reactors with emphasis on two-phase thermosyphoning. It utilizes predictions of a transient thermohydraulics computer code and describes experiments done for the purpose of verifying these predictions. Predictions are compared with single-phase thermosyphoning tests done during commissioning of the Gentilly-2 and Point Lepreau CANDU 600 reactors. (orig.)

Simulating fission product transients via the history-based local-parameter methodology

International Nuclear Information System (INIS)

Jenkins, D.A.; Rouben, B.; Salvatore, M.

1993-01-01

This paper describes the fission-product-calculation capacity of the history-based local-parameter methodology for evaluating lattice properties for use in core-tracking calculations in CANDU reactors. In addition to taking into account the individual past history of each bundles flux/power level, fuel temperature, and coolant density and temperature that the bundle has seen during its stay in the core, the latest refinement of the history-based method provides the capability of fission-product-drivers. It allows the bundle-specific concentrations of the three basic groups of saturating fission products to be calculated in steady state or following a power transient, including long shutdowns. The new capability is illustrated by simulating the startup period following a typical long-shutdown, starting from a snapshot in the Point Lepreau operating history. 9 refs., 7 tabs

f(R)-theories of gravity and gravitational baryogenesis

Energy Technology Data Exchange (ETDEWEB)

Lambiase, G; Scarpetta, G [Dipartimento di Fisica ' E.R. Caianiello' Universita di Salerno, 84081 Baronissi (Italy); INFN - Gruppo Collegato di Salerno (Italy)

2007-05-15

The mechanism for generating the baryon asymmetry in the Universe is discussed in the framework of f(R)-theories of gravity. The gravitational baryogenesis, based on the coupling between the Ricci scalar curvature R and the baryon current, allows to determine the form of gravity Lagrangian, i.e. L(R) {approx} R{sup n}. The current bound on the observed matter-antimatter asymmetry and Big Bang Nucleosynthesis data lead to n = 0.97.

On the emergence theme of physics

CERN Document Server

Carroll, Robert

2010-01-01

The book surveys mathematical relations between classical and quantum mechanics, gravity, time and thermodynamics from various points of view and many sources (with appropriate attribution). The emergence theme is developed with an emphasis on the meaning via mathematics. A background theme of Bohemian mechanics and connections to the quantum equivalence principle of Matone et al. is also developed in great detail. Some original work relating the quantum potential and Ricci flow is also included.

Existence of parallel spinors on non-simply-connected Riemannian manifolds

International Nuclear Information System (INIS)

McInnes, B.

1997-04-01

It is well known, and important for applications, that Ricci-flat Riemannian manifolds of non-generic holonomy always admit a parallel [covariant constant] spinor if they are simply connected. The non-simply-connected case is much more subtle, however. We show that a parallel spinor can still be found in this case provided that the [real] dimension is not a multiple of four, and provided that the spin structure is carefully chosen. (author). 10 refs

Uued plaadid

Index Scriptorium Estoniae

2005-01-01

Uutest heliplaatidest Robbie Williams "Greatest Hits", R.E.M. "Around The Sun", Busted "Busted Live", Eminem "Encore", Seal "Seal Best1991-2004", The Donnas "Gold Medal", Kylie Minogue "Ultimate Kylie", Jay-Z/Linkin Park "Collision Course", Westlife "...Allow Us To Be Frank", "Barbie Girls", "Bridget Jones. The Edge Of Reason, Brian McFadden "Irish Son", Ja Rule "R.U.L.E."

Rhesus Monkeys (Macaca Mulatta) Demonstrate Robust Memory for What and Where, but Not When, in an Open-Field Test of Memory

Science.gov (United States)

Hampton, R.R.; Hampstead, B.M.; Murray, E.A.

2005-01-01

We adapted a paradigm developed by Clayton and Dickinson (1998), who demonstrated memory for what, where, and when in scrub jays, for use with rhesus monkeys. In the study phase of each trial, monkeys found a preferred and a less-preferred food reward in a trial-unique array of three locations in a large room. After 1h, monkeys returned to the…

Elementary Particle Physics at Baylor (Final Report)

Energy Technology Data Exchange (ETDEWEB)

Dittmann, J.R.

2012-08-25

This report summarizes the activities of the Baylor University Experimental High Energy Physics (HEP) group on the Collider Detector at Fermilab (CDF) experiment from August 15, 2005 to May 31, 2012. Led by the Principal Investigator (Dr. Jay R. Dittmann), the Baylor HEP group has actively pursued a variety of cutting-edge measurements from proton-antiproton collisions at the energy frontier.

Renee M Borges

Indian Academy of Sciences (India)

Renee M Borges · More Details Fulltext PDF. Volume 7 Issue 11 November 2002 pp 2-5 Article-in-a-Box. Stephen Jay Gould: A View of Life · Renee M Borges · More Details Fulltext PDF. Volume 10 Issue 7 July 2005 pp 21-33 General Article. Polemics and Synthesis: Ernst Mayr and Evolutionary Biology · Renee M Borges.

A5: Automated Analysis of Adversarial Android Applications

Science.gov (United States)

2014-06-03

A5: Automated Analysis of Adversarial Android Applications Timothy Vidas, Jiaqi Tan, Jay Nahata, Chaur Lih Tan, Nicolas Christin...detecting, on the device itself, that an application is malicious is much more complex without elevated privileges . In other words, given the...interface via website. Blasing et al. [7] describe another dynamic analysis system for Android . Their system focuses on classifying input applications as

African Zoology - Vol 23, No 4 (1988)

African Journals Online (AJOL)

Book Reviews · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Lynne Whiffler, S.G. Compton, M.R. Perrin, M.D. Picker, M.R. Perrin, P.C. Magnuson, Jay O'Keefe, A.N. Hodgson, P Hewitt, S Endrödy-Younga, L.G. Underhill, H.M. Dott, R.T.F. Bernard, C.R. Brown, 370- ...

State-dependent choice and ecological rationality.

Science.gov (United States)

Nevai, Andrew L; Waite, Thomas A; Passino, Kevin M

2007-08-07

Decision makers who minimize costly errors should flexibly adjust the way they trade off competing demands, depending on their current state. We explore how state (amount of hoarded food) affects willingness to take extra predation risk to obtain larger food rewards, particularly in animals that may overemphasize safety. Assuming a sigmoid fitness function, we explore how a supplement in state influences this willingness trade danger for food energy. Above a threshold, the model predicts the supplement will weaken this willingness. Incremental increases in state in the deceleratory phase yield smaller fitness gains, so it pays to increase emphasis on safety after receiving a supplement. Below this threshold, the model makes the opposite prediction because incremental increases in state yield bigger fitness gains and so it pays to decrease emphasis on safety. We use the model to explain why hoarding gray jays (Perisoreus canadensis) were induced by an experimental subsidy to accept greater danger. This formerly puzzling finding makes sense if the jays' effective hoard was relatively small, due to theft and decomposition. We discuss adaptive state-dependent choice as a general explanation for apparently irrational behavior.

Holonomy of Einstein Lorentzian manifolds

International Nuclear Information System (INIS)

Galaev, Anton S

2010-01-01

The classification of all possible holonomy algebras of Einstein and vacuum Einstein Lorentzian manifolds is obtained. It is shown that each such algebra appears as the holonomy algebra of an Einstein (resp. vacuum Einstein) Lorentzian manifold; the direct constructions are given. Also the holonomy algebras of totally Ricci-isotropic Lorentzian manifolds are classified. The classification of the holonomy algebras of Lorentzian manifolds is reviewed and a complete description of the spaces of curvature tensors for these holonomies is given.

Religious Nonconformity and cultural Dynamics: The Case of the Dutch Collegiants

OpenAIRE

Ricci, Rosa

2015-01-01

Rosa Ricci Summary of the PHD Dissertation: Religious Nonconformity and cultural Dynamics: The Case of the Dutch Collegiants There is ample reason to engage in research around the Collegiants, a minority religious movement in the Netherlands of the 17th century. An exploration of this topic can be interesting not only for a contribution to the history of Religion but also to understand the development of some central concept in the early modernity. Prominent, in this research, is the ...

Sasakian manifolds with purely transversal Bach tensor

Science.gov (United States)

Ghosh, Amalendu; Sharma, Ramesh

2017-10-01

We show that a (2n + 1)-dimensional Sasakian manifold (M, g) with a purely transversal Bach tensor has constant scalar curvature ≥2 n (2 n +1 ) , equality holding if and only if (M, g) is Einstein. For dimension 3, M is locally isometric to the unit sphere S3. For dimension 5, if in addition (M, g) is complete, then it has positive Ricci curvature and is compact with finite fundamental group π1(M).

Uudiseid maailmast / Nele-Eva Steinfeld

Index Scriptorium Estoniae

Steinfeld, Nele-Eva

2012-01-01

Lühisõnumeid muusikamaailmast: Paavo Järvist saab Tokyo NHK sümfooniaorkestri peadirigent. Suri Dietrich Fischer-Dieskau. Avastati Antonio Vivaldi uusi teoseid. Glenn Gouldi klaver jõudis Ottawa Rahvuslikku Kunstide Keskusesse. Sbeliuse noodistustarkvara peakorter Suurbritannias suleti. Viini Riigiooperi rekordiliselt kasumlik hooaeg. Bayreuthi markkrahvi ooperimaja arvati UNESCO maailmapärandi nimistusse. Erkki-Sven Tüüri ooperi "Wallenberg" uuslavastus Karlsruhes. Pianist Mihkel Poll andis kontserdi Wigmore Hallis. Rahvusvaheline heliloojate rostrum Stockholmis. Suri viiuldaja Ruggiero Ricci. Lahkus pianist Mihaela Ursuleasa

Dynamics of Chern-Simons vortices

International Nuclear Information System (INIS)

Collie, Benjamin; Tong, David

2008-01-01

We study vortex dynamics in three-dimensional theories with Chern-Simons interactions. The dynamics is governed by motion on the moduli space M in the presence of a magnetic field. For Abelian vortices, the magnetic field is shown to be the Ricci form over M; for non-Abelian vortices, it is the first Chern character of a suitable index bundle. We derive these results by integrating out massive fermions and following the fate of their zero modes.

S- and T-self-dualities in dilatonic f(R) theories

Energy Technology Data Exchange (ETDEWEB)

Rador, Tonguc [Bogazici University, Department of Physics, Istanbul (Turkey); Izmir Institute of Technology, Department of Physics, Izmir (Turkey)

2017-12-15

We search for theories, in general spacetime dimensions, that would incorporate a dilaton and higher powers of the scalar Ricci curvature such that they have exact S- or T-self-dualities. The theories we find are free of Ostrogradsky instabilities. We also show that within the framework we are confining ourselves, a theory of the form mentioned above cannot have both T- and S-dualities except for the case where the action is linear in the scalar curvature. (orig.)

Uus plaat

Index Scriptorium Estoniae

2005-01-01

Uutest plaatidest A-Ha "The Singles 1984-2004", Andrea Bocelli "Andrea", Def Leppard "Best Of", Elton John "Peachtree Road", Eminem "Encore", ERA "The Very Best Of", Jay-Z and Linkin Park "Callision Course", Kylie Minogue "Ultimate Kylie", Scooter "Mind the Gap", Shania Twain "Greatest Hits", Tina Turner "All The Best", "True Love 2", U2 "How To Dismantle An Atomic Bomb", "Bridget Jones. Soundtrack"

Swimming Performance of Adult Asian Carp: Field Assessment Using a Mobile Swim Tunnel

Science.gov (United States)

2016-08-01

ERDC/TN ANSRP-16-1 August 2016 Approved for public release; distribution is unlimited. Swimming Performance of Adult Asian Carp: Field...Assessment Using a Mobile Swim Tunnel by Jan Jeffrey Hoover, Jay A. Collins, Alan W. Katzenmeyer, and K. Jack Killgore PURPOSE: Empirical swim speed...test in traditional laboratory swim tunnels. Biologists from the Engineer Research and Development Center (ERDC) Environmental Laboratory (EL), with

Precipitating the Decline of Al-Shabaab: A Case Study in Leadership Decapitation

Science.gov (United States)

2015-12-01

disbanding leadership councils, and relying on an autocratic leadership style .150 Militarily, Al-Shabaab went back to its roots...Godane’s autocratic leadership methods severely degraded the strength and influence of Al-Shabaab, and would likely have continued to isolate the group...SHABAAB: A CASE STUDY IN LEADERSHIP DECAPITATION by Brett M. Butler December 2015 Thesis Advisor: Bradley Jay Strawser Second Reader: Anna Simons

Development and Testing of a Rotating Detonation Engine Run on Hydrogen and Air

Science.gov (United States)

2012-03-22

Jay Rutledge (Member) Date v AFIT/GAE/ENY/12-M36 Abstract Rotating detonation engines ( RDEs ) have the potential for greater...efficiencies over conventional engines by utilizing pressure gain combustion. A new modular RDE (6 in diameter) was developed and successfully run on...hydrogen and standard air. The RDE allows for variation of injection scheme and detonation channel widths. Tests provided the operational space of the

Measuring the Foundation of Homeland Security

Science.gov (United States)

2007-03-01

Pirak Kevin Eack Susan Pyle Chuck Eaneff Joseph Saitta Susan Fernandez Shelly Schechter Helen Fitzpatrick Rick Schwein Jay...multiple disciplines. The scope of this literature review is to cast a broad net and then narrow to specific literature related to Homeland Security...Suez Canal. His successes as a planner, diplomat and promoter made him the most celebrated man in Europe. Because of these successes, De Lesseps

Military Medicine: One Profession Not Two

Science.gov (United States)

2013-12-13

47. New York, NY: Springer Science + Business Media. Luvaas, Jay. 1986. Frederick the Great: The education of a great captain. In The John Biggs ...based on individual assignments undermines the nature of mixed agency related tensions that dual professionals experience. John Lunsroth suggests...Lunsroth, John . 2008. Torture and the regulation of the health care professions. In Physicians at War: The Dual-Loyalties Challenge, ed. Fritz Allhoff, 127

STS-47 Astronaut Crew at Pad B for TCDT, Emergency Egress Training, and Photo Opportunity

Science.gov (United States)

1992-01-01

The crew of STS-47, Commander Robert L. Gibson, Pilot Curtis L. Brown, Payload Commander Mark C. Lee, Mission Specialists N. Jan Davis, Jay Apt, and Mae C. Jemison, and Payload Specialist Mamoru Mohri are seen during emergency egress training. Then Commander Gibson introduces the members of the crew and they each give a brief statement about the mission and answer questions from the press.

Demonstration and Commercialization of the Sediment Ecosystem Assessment Protocol

Science.gov (United States)

2017-01-01

provided in Appendix F. Of those measurements recorded, only dissolved copper was found to exceed national ambient marine water quality (http...measurement of water quality parameters. The Battelle staff member found the SEA Ring easy to operate, but noted that care must be taken when...ERDC); Jason Conder (Geosyntec, Inc.); Brian Hester, Jay Word , and staff of the Ramboll Environ Port Gamble Bioassay Laboratory; and laboratory and

Disentangling plastic and genetic changes in body mass of Siberian jays

NARCIS (Netherlands)

Gienapp, P.; Merilä, J.

2014-01-01

Spatial and temporal phenotypic differentiation in mean body size is of commonplace occurrence, but the underlying causes remain often unclear: both genetic differentiation in response to selection (or drift) and environmentally induced plasticity can create similar phenotypic patterns. Studying

Pildi vaatenurgast : Fotograafilise tähenduse tõlgenduslikud strateegiad / Jay Ruby

Index Scriptorium Estoniae

Ruby, Jay, 1935-

2010-01-01

Fotograafia rollist antropoloogias ja selle sihist, fotode tõlgendamisest ja kontekstist, pildiliste sõnumite osast kultuuris. Foto kui kunst, kui esteetiline objekt versus foto kui reaalsuse "vahendamata" salvestus - need levinud seisukohad häirivad fotode teadusliku interpretatsiooni väljakujunemist ja fotode antropoloogilise tõlgendamise süsteemi väljatöötamist. Eesmärgiks peaks olema pakkuda antropoloogidele kommunikatsiooni pildilist vahendit

Spatial patterns of seasonal distribution of Corvidae (the case of urban habitats

Directory of Open Access Journals (Sweden)

A. V. Matsyura

2016-09-01

Full Text Available Corvids in Zhytomyr city reach maximum density in the winter period. Rooks and Eurasian Jackdaws were the most abundant species in winter, usually feeding in multispecies flocks and forming collective roosts.Suburban green areas (buffer zones were characterized by a considerably high diversity of Corvidae species: this habitat was occupied by all six species. We also registered the highest density of Eurasian Jays and Hooded Crows in this habitat. The green areas in the city center were also characterized by significant corvid density, especially during the breeding season. The maximum breeding density of Rooks was in these habitats, which held 6 of 12 identified urban colonies in Zhytomyr. We found that the European Magpies, Eurasian Jays, and Hooded Crows also had high breeding success here. Eurasian Jackdaws occurred here only in autumn and winter, when they fed together with Rooks on lawns, gardens, and parks. With stable snow cover the Rook density in habitats of the green areas decreased due to the depletion of food resources.The individual buildings zone of the city were characterized by the lowest density of all corvid species, except for European Magpies and Eurasian Jays. The number of common species (Rooks, Eurasian Jackdaws, and Hooded Crows was low because of shortage of food resources, lack of sites for large roosting flocks and shortage of suitable nesting sites. However, Eurasian Magpies reached one of their highest densities in this habitat (12.8 birds/km2. This species was registered in habitats around private buildings all the year round, successfully nesting in the yards of private houses and on trees in the streets. Its breeding density was 11.2 birds/km2.During three years of research (2009–2012 the density of all corvids except for European Magpie, practically did not change, although we determined a slight positive trend for all the species. The strong increase in the number of Eurasian Jackdaws could be explained by

On Born's deformed reciprocal complex gravitational theory and noncommutative gravity

International Nuclear Information System (INIS)

Castro, Carlos

2008-01-01

Born's reciprocal relativity in flat spacetimes is based on the principle of a maximal speed limit (speed of light) and a maximal proper force (which is also compatible with a maximal and minimal length duality) and where coordinates and momenta are unified on a single footing. We extend Born's theory to the case of curved spacetimes and construct a deformed Born reciprocal general relativity theory in curved spacetimes (without the need to introduce star products) as a local gauge theory of the deformed Quaplectic group that is given by the semi-direct product of U(1,3) with the deformed (noncommutative) Weyl-Heisenberg group corresponding to noncommutative generators [Z a ,Z b ]≠0. The Hermitian metric is complex-valued with symmetric and nonsymmetric components and there are two different complex-valued Hermitian Ricci tensors R μν ,S μν . The deformed Born's reciprocal gravitational action linear in the Ricci scalars R,S with Torsion-squared terms and BF terms is presented. The plausible interpretation of Z μ =E μ a Z a as noncommuting p-brane background complex spacetime coordinates is discussed in the conclusion, where E μ a is the complex vielbein associated with the Hermitian metric G μν =g (μν) +ig [μν] =E μ a E-bar ν b η ab . This could be one of the underlying reasons why string-theory involves gravity

Positive energy theorem in generalized Kaluza-Klein theories of higher dimensions

International Nuclear Information System (INIS)

Moreschi, O.M.

1983-01-01

The technique of using spinors in the proof of positive energy theorems in 4 dimensions is extended to the case of Kaluza-Klein theories in spaces of 4 + n dimensions. First a useful presentation of generalized Kaluza-Klein theories is introduced, in which just from the observation of conformal symmetries it is possible to detect a nice splitting of the Ricci tensor into a 4-dimensional Ricci part and a Yang-Mills part, among others. Consideration of linear dependence among the symmetries is not excluded in this treatment. Relevant to the introduction of spinors, a discussion of Clifford Algebras is presented. In particular a real representation of these algebras is introduced for spaces of higher dimensions and its structure is analyzed. The Lie derivative of spinors is presented probably more clearly than in former treatments. After the introduction of these preliminary themes, a brief review of the relevant aspects of positive energy theorems in 4 dimensions is presented, followed by the extension of these ideas to the case of 5 dimensions. Here an earlier result involving gravitational mass and electromagnetic charges is improved. Finally the results are generalized to spaces of 4 + n dimensions, and a more complicated condition to be satisfied by the usual matter tensor is discovered. This procedure leads to a natural definition of invariant Yang-Mills charges, which is compared with former studies

Weak lensing in generalized gravity theories

International Nuclear Information System (INIS)

Acquaviva, Viviana; Baccigalupi, Carlo; Perrotta, Francesca

2004-01-01

We extend the theory of weak gravitational lensing to cosmologies with generalized gravity, described in the Lagrangian by a generic function depending on the Ricci scalar and a nonminimal coupled scalar field. We work out the generalized Poisson equations relating the dynamics of the fluctuating components to the two gauge-invariant scalar gravitational potentials, fixing the contributions from the modified background expansion and fluctuations. We show how the lensing equation gets modified by the cosmic expansion as well as by the presence of anisotropic stress, which is non-null at the linear level both in scalar-tensor gravity and in theories where the gravitational Lagrangian term features a nonminimal dependence on the Ricci scalar. Starting from the geodesic deviation, we derive the generalized expressions for the shear tensor and projected lensing potential, encoding the spacetime variation of the effective gravitational constant and isolating the contribution of the anisotropic stress, which introduces a correction due to the spatial correlation between the gravitational potentials. Finally, we work out the expressions of the lensing convergence power spectrum as well as the correlation between the lensing potential and the integrated Sachs-Wolfe effect affecting cosmic microwave background total intensity and polarization anisotropies. To illustrate phenomenologically the effects, we work out approximate expressions for the quantities above in extended quintessence scenarios where the scalar field coupled to gravity plays the role of the dark energy

Designing for human performance - CANDU electrical panels - then and now

International Nuclear Information System (INIS)

Patterson, B.K.

2003-01-01

Experience has shown that few changes are made to CANDU control center panels once plants are in service. There are several reasons for this, for example, operational conservatism, outage minimization, avoidance of retraining effort, and perhaps lack of appreciation of improvement opportunities. Since the initial CANDU 6 plants were designed, the industry has moved forward with adoption of new approaches to control room interface design that have introduced changes in design principles and emphasis. At Point Lepreau, the electrical panels have remained virtually unchanged since initial design. The author, the original electrical system commissioning engineer, reviews the design considerations that led to the initial panel design, reviews some of the operational limitations discovered during use, and offers some suggestions on improvement directions, if these panels were being designed today, that would offer an implementation to better support operator tasks. (author)

Towards a generic user support system (GUS)

International Nuclear Information System (INIS)

Garland, W.J.; Wilson, R.J.

1993-01-01

One relevant issue confronting the operator of a nuclear power plant is information and task overload. The goal, then, of the various developers is to improve the current situations by creating an environment where the operator can perform at optimum capacity. This is to be accomplished by providing tools and techniques which reduce operator involvement in low level tasks (freeing up time for higher level cognitive tasks) and assist in information and knowledge manipulation so that high level tasks can be performed more efficiently. This paper reviews the operational environment of nuclear plants from the viewpoint of engineering design and from the viewpoint of the operators and technical support staff. Principles are advanced for a generic operator companion. These design principles are being applied to a test case: the Point Lepreau NGS secondary side central sampling system. 6 refs., 6 figs

Managing organizational culture within a management system

International Nuclear Information System (INIS)

Comeau, L.; Watts, G.

2009-01-01

The Point Lepreau Generating Station (PLGS) is currently undergoing a major refurbishment of its nuclear reactor. At the same time, a small team is designing the organization that will operate the plant after refurbishment. This paper offers a high level overview of the Post-Refurbishment Organization (PRO) project and will focus primarily on the approach used to address organizational culture and human system dynamics. We will describe how various tools, used to assess organization culture, team performance, and individual self-understanding, are used collectively to place the right person in the right position. We will explain how the career system, Pathfinder, is used to integrate these tools to support a comprehensive model for organization design and development. Finally, we demonstrate how the management of organizational cultural and human system dynamics are integrated into the PLGS Integrated Management System. (author)