11,998 research outputs found
Higher-dimensional models in gravitational theories of quarticLagrangians
Ten-dimensional models, arising from a gravitational action which includes
terms up to the fourth order in curvature tensor, are discussed. The spacetime
consists of one timelike dimension and two maximally symmetric subspaces,
filled with matter in the form of an anisotropic fluid. Numerical integration
of the cosmological field equations indicates that exponential, as well as
power law, solutions are possible. We carry out a dynamical study of the
results in the H_{ext} - H_{int} plane and confirm the existence of
"attractors" in the evolution of the Universe. Those attracting points
correspond to "extended De Sitter" spacetimes, in which the external space
exhibits inflationary expansion, while the internal one contracts.Comment: LaTeXfile, 22 page
Multi-jet Production in Hadron Collisions
The advent of high-energy hadron colliders necessitates efficient and
accurate computation of multi-jet production processes, both as QCD processes
in their own right and as backgrounds for other physics. The algorithm that
performs these tasks and a brief numerical study of multi-jet processes are
presented.Comment: 21 pages, 9 figure
(1,0) superconformal theories in six dimensions and Killing spinor equations
We solve the Killing spinor equations of 6-dimensional (1,0) superconformal
theories in all cases. In particular, we derive the conditions on the fields
imposed by the Killing spinor equations and demonstrate that these depend on
the isotropy group of the Killing spinors. We focus on the models proposed by
Samtleben et al in \cite{ssw} and find that there are solutions preserving 1,2,
4 and 8 supersymmetries. We also explore the solutions which preserve 4
supersymmetries and find that many models admit string and 3-brane solitons as
expected from the M-brane intersection rules. The string solitons are smooth
regulated by the moduli of instanton configurations.Comment: 26 page
Customer oriented and proactive selling in small Finnish companies
Abstract. Solving the customerâs âpainâ is a well-known mantra in business, as is taking the initiative. Customer orientation describes the former in terms of understanding the customerâs needs and striving to satisfy them. The latter is many times associated with being proactive when acting. Both these traits have been associated with higher performance and other positive effects in sales. Small businesses often face difficulties competing against larger firms due to lack of resources and knowledge when navigating their environments. Customer orientation and proactiveness in their approach to sales could help them partly overcome these difficulties by providing a way to increase sales performance. This study seeks to uncover whether customer orientation and proactiveness are more prevalent in certain types of small businesses and to add to the understanding of small business sales.
The study examines customer orientation and proactiveness literature along with literature about the divisions in the marketing and sales of B2B versus B2C and products versus services. The construct of customer orientation includes customer service orientation, solution orientation and an emphasis on analysing customer behaviour. The proactiveness categories are whether the firm acquires new sales via its action, the customers action, or the action of both. The aim is to understand whether higher levels of the two traits are associated with a certain type of customers or offerings and to shed light on their coexistence and their effect on sales performance. The study utilizes a questionnaire distributed to various small companies in the Oulu region of Finland, to assess their sales capabilities. Answers to questions pertaining to the above traits were selected and statistically analysed to identify inferences in the data about the previous associations. Altogether, the analysis looked at 242 respondents from 32 companies, from various industries. The study is part of the âSales is a Kingâ project, which is being conducted by the University of Oulu and the MicroENTRE research body.
The data analysis showed interesting results. It suggests that the existence of higher customer orientation levels is not related to a more proactive sales approach and vice versa. Also, the two behaviours do not vary between customer and offering types and only proactiveness is associated with higher sales performance. Although, using the customer orientation construct yielded the above results, further analysis on the customer service orientation and solution orientation items showed otherwise. The former was higher in B2B firms than those that sell to both customer types and in product selling firms as opposed to those that sell both offering types. For the latter, companies that sold products exhibited higher solution orientation levels than those that sold both offerings. The study contributes to researchers and practitioners alike, by enhancing the understanding of customer oriented and proactive selling in small businesses
Isotropic inverse-problem approach for two-dimensional phase unwrapping
In this paper, we propose a new technique for two-dimensional phase
unwrapping. The unwrapped phase is found as the solution of an inverse problem
that consists in the minimization of an energy functional. The latter includes
a weighted data-fidelity term that favors sparsity in the error between the
true and wrapped phase differences, as well as a regularizer based on
higher-order total-variation. One desirable feature of our method is its
rotation invariance, which allows it to unwrap a much larger class of images
compared to the state of the art. We demonstrate the effectiveness of our
method through several experiments on simulated and real data obtained through
the tomographic phase microscope. The proposed method can enhance the
applicability and outreach of techniques that rely on quantitative phase
evaluation
Extended dust emission and atomic hydrogen, a reservoir of diffuse H_2 in NGC 1068
We report on sensitive sub-mm imaging observations of the prototype
Seyfert~2/starburst galaxy NGC 1068 at 850 m and 450 m using the
Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell
Telescope (JCMT). We find clear evidence of dust emission associated with the
extended HI component which together with the very faint CO J=1--0
emission give a gas-to-dust ratio of . This contrasts with the larger ratio estimated within a galactocentric radius of kpc, where the
gas is mostly molecular and starburst activity occurs. The large gas-to-dust
ratio found for the starburst region is attributed to a systematic overestimate
of the molecular gas mass in starburst environments when the luminosity of the
CO J=1--0 line and a standard galactic conversion factor is used. On
the other hand sub-mm imaging proves to be a more powerful tool than
conventional CO imaging for revealing the properties of the diffuse
that coexists with HI. This molecular gas phase is characterized by low
densities ( cm), very faint emission from
sub-thermally excited CO, and contains more mass than HI, namely .Comment: Accepted for publication in the Astrophysical Journal Letter
Dynamics of Scalar Fields in the Background of Rotating Black Holes
A numerical study of the evolution of a massless scalar field in the
background of rotating black holes is presented. First, solutions to the wave
equation are obtained for slowly rotating black holes. In this approximation,
the background geometry is treated as a perturbed Schwarzschild spacetime with
the angular momentum per unit mass playing the role of a perturbative
parameter. To first order in the angular momentum of the black hole, the scalar
wave equation yields two coupled one-dimensional evolution equations for a
function representing the scalar field in the Schwarzschild background and a
second field that accounts for the rotation. Solutions to the wave equation are
also obtained for rapidly rotating black holes. In this case, the wave equation
does not admit complete separation of variables and yields a two-dimensional
evolution equation. The study shows that, for rotating black holes, the late
time dynamics of a massless scalar field exhibit the same power-law behavior as
in the case of a Schwarzschild background independently of the angular momentum
of the black hole.Comment: 14 pages, RevTex, 6 Figure
Strings in Kerr-Newmann Black Holes
We study the evolution of strings in the equatorial plane of a Kerr-Newmann
black hole. Writting the equations of motion and the constraints resulting from
Hamilton's principle, three classes of exact solutions are presented, for a
closed string, encircling the black hole. They all depend on two arbitrary
integration functions and two constants. A process of extracting energy is
examined for the case of one of the three families of solutions. This is the
analog of the Penrose process for the case of a particle.Comment: 14 pages, no figures, LaTeX. To appear in Gen. Rel. Gra
Penrose Limits and Spacetime Singularities
We give a covariant characterisation of the Penrose plane wave limit: the
plane wave profile matrix is the restriction of the null geodesic
deviation matrix (curvature tensor) of the original spacetime metric to the
null geodesic, evaluated in a comoving frame. We also consider the Penrose
limits of spacetime singularities and show that for a large class of black
hole, cosmological and null singularities (of Szekeres-Iyer ``power-law
type''), including those of the FRW and Schwarzschild metrics, the result is a
singular homogeneous plane wave with profile , the scale
invariance of the latter reflecting the power-law behaviour of the
singularities.Comment: 9 pages, LaTeX2e; v2: additional references and cosmetic correction
Zero-dimensional field theory
A study of zero-dimensional theories, based on exact results, is presented.
First, relying on a simple diagrammatic representation of the theory, equations
involving the generating function of all connected Green's functions are
constructed. Second, exact solutions of these equations are obtained for
several theories. Finally, renormalization is carried out. Based on the
anticipated knowledge of the exact solutionsthe full dependence on the
renormalized coupling constant is studied.Comment: 38 pages, LaTe
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