2,674 research outputs found
Brane World in a Topological Black Hole Bulk
We consider a static brane in the background of a topological black hole, in
arbitrary dimensions. For hyperbolic horizons, we find a solution only when the
black hole mass assumes its minimum negative value. In this case, the tension
of the brane vanishes, and the brane position coincides with the location of
the horizon. For an elliptic horizon, we show that the massless mode of
Randall-Sundrum is recovered in the limit of large black hole mass.Comment: Latex, 8 pages, v2: Additional references, to appear in MPL
Anchored Cutoff Structure Design and Construction
As part of a new cogeneration plant being built in Jacksonville, Florida, a 31-foot deep excavation was required to install a 173-foot by 53-foot coal unloading structure in loose to medium-dense fine sands with shallow ground water. A conventional system of excavation support would typically consist of installing and maintaining a dewatering system and driving sheet piles. However, due to the potential for shallow contaminated ground water at the site and a restricted amount of inflow treatment capacity, a nearly complete cutoff or bathtub structure was required. A system that is relatively new to the United States was designed and installed to meet the difficult needs of the site. The system consisted of a sheet pile perimeter wall placed in a cement-bentonite slurry trench, tied back with soil anchors, in conjunction with an anchored six to eight-foot thick soilcrete base mat installed using jet-grouting techniques. This case history provides details regarding design and installation of the anchored cutoff structure. Specifically, design assumptions regarding lateral earth pressures are presented along with predicted versus actual anchor loads for various construction stages. In addition, the results of finite element seepage analysis of the soilcrete base cutoff, and a unique hydrostatic uplift analysis are also presented
Developing And Implementing A Measure Of Sustainability For Workforce And Economic Development Projects In Northeast Pennsylvania
As part of a Wall Street West (WSW) grant, a project team was assembled to investigate the effectiveness of other WSW grantees working on various projects to impact the long term economic development of the financial services sector of the Northeast Pennsylvania (NEPA) corridor. Because sustainability of grant work was deemed critical by project leaders, a literature search was undertaken to identify factors that contribute to sustainability. Twelve factors were culled from the literature, reviewed with WSW executives and project grantees, and ultimately combined (using a BARS assessment methodology) to form an economic or workforce development Sustainability Index. This paper reviews the logic and the steps taken to develop the Sustainability Index, discusses the validity and reliability of the instrument, and shows how it was used to measure and report the relative importance of sustainability factors in economic development activities. The authors issue a call to action to further develop and refine the instrument across a variety of application venues
Initial Data for General Relativity with Toroidal Conformal Symmetry
A new class of time-symmetric solutions to the initial value constraints of
vacuum General Relativity is introduced. These data are globally regular,
asymptotically flat (with possibly several asymptotic ends) and in general have
no isometries, but a group of conformal isometries. After
decomposing the Lichnerowicz conformal factor in a double Fourier series on the
group orbits, the solutions are given in terms of a countable family of
uncoupled ODEs on the orbit space.Comment: REVTEX, 9 pages, ESI Preprint 12
Mass and angular-momentum inequalities for axi-symmetric initial data sets I. Positivity of mass
We extend the validity of Brill's axisymmetric positive energy theorem to all
asymptotically flat initial data sets with positive scalar curvature on simply
connected manifolds.Comment: 33 pages in A
General K=-1 Friedman-Lema\^itre models and the averaging problem in cosmology
We introduce the notion of general K=-1 Friedman-Lema\^itre (compact)
cosmologies and the notion of averaged evolution by means of an averaging map.
We then analyze the Friedman-Lema\^itre equations and the role of gravitational
energy on the universe evolution. We distinguish two asymptotic behaviors:
radiative and mass gap. We discuss the averaging problem in cosmology for them
through precise definitions. We then describe in quantitative detail the
radiative case, stressing on precise estimations on the evolution of the
gravitational energy and its effect in the universe's deceleration. Also in the
radiative case we present a smoothing property which tells that the long time
H^{3} x H^{2} stability of the flat K=-1 FL models implies H^{i+1} x H^{i}
stability independently of how big the initial state was in H^{i+1} x H^{i},
i.e. there is long time smoothing of the space-time. Finally we discuss the
existence of initial "big-bang" states of large gravitational energy, showing
that there is no mathematical restriction to assume it to be low at the
beginning of time.Comment: Revised version. 32 pages, 1 figur
Exploring Predictability Of Instructor Ratings Using A Quantitative Tool For Evaluating Soft Skills Among MBA Students
Academic researchers have often touted the growing importance of “soft skills” for modern day business leaders, especially leadership and communication skills.  Despite this growing interest and attention, relatively little work has been done to develop and validate tools to assess soft skills. Forty graduate students from nine MBA courses completed the McCann Soft Skills Assessment Tool - a paper-pencil test designed to measure leadership, teamwork, critical thinking, logical reasoning, communication, and holistic thinking. These students were also rated by their instructors on the same six dimensions in an attempt to validate the soft skills instrument. Results showed significant correlations between leadership and communication assessment scores and faculty ratings of students on the same dimensions; however none of the other four soft skill dimensions were empirically validated. Data also indicated moderate test – retest reliability for the assessment tool. While some limitations are acknowledged in the current study, findings suggest that further refinement and empirical validation of the McCann Soft Skills Assessment Tool can better aid practitioners in understanding and developing these important dimensions of business competency
Uniqueness of the asymptotic AdS3 geometry
We explicitly show that in (2+1) dimensions the general solution of the
Einstein equations with negative cosmological constant on a neigbourhood of
timelike spatial infinity can be obtained from BTZ metrics by coordinate
transformations corresponding geometrically to deformations of their spatial
infinity surface. Thus, whatever the topology and geometry of the bulk, the
metric on the timelike extremities is BTZ.Comment: LaTeX, 8 pages, no figures, version that will appear in Class. Quant.
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Manifold structures for sets of solutions of the general relativistic constraint equations
We construct manifold structures on various sets of solutions of the general
relativistic initial data sets.Comment: latex2e, 32 A4 pages, minor correction
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