11,246 research outputs found
A variational principle for actions on symmetric symplectic spaces
We present a definition of generating functions of canonical relations, which
are real functions on symmetric symplectic spaces, discussing some conditions
for the presence of caustics. We show how the actions compose by a neat
geometrical formula and are connected to the hamiltonians via a geometrically
simple variational principle which determines the classical trajectories,
discussing the temporal evolution of such ``extended hamiltonians'' in terms of
Hamilton-Jacobi-type equations. Simplest spaces are treated explicitly.Comment: 28 pages. Edited english translation of first author's PhD thesis
(2000
Calculation of the two-photon decay width of the f_0(980) scalar meson
The applicability of the quasi-static approximation for calculating the
two-photon annihilation rate of the scalar f_0(980) meson envisaged as a K\bar
K molecule is critically re-examined. It is shown that the validity of this
approximation depends on the detailed interplay between the momentum dependence
of the annihilation amplitude and the momentum transform of the bound state
wave function of the annihilating pair. The approximation becomes invalid when
these two scales of variation are similar. An improved method of calculation
based on the inclusion of electromagnetic corrections to the kernel of the
Bethe-Salpeter equation for the interacting K\bar K pair is outlined to cover
this case and applied to re-evaluate the two-photon decay width for f_0(980) in
a one boson exchange model for the interkaon interaction. The corrections are
significant and result in a much better agreement with experiment.Comment: 14 pages, 3 figures. Fig.3 replaced. Additional remarks with
reference
IWP strategy: TechFrame
A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and EconomicsTechFrame is an IT Portuguese company that provides a software package to Industrial
Property Agents to manage their clients’ portfolio. In Portugal this firm is a market leader,
having a share of 80%, and facing no competition, although some substitutes do exist. With this
scenario in the Portuguese market, TechFrame has low expectations of increasing business
volume, due to the specificity of this industry.
In order to increase sales volume and focusing on their core competences, TechFrame´s best
solution is to expand into new markets. Currently this firm is considering some
internationalization processes into the French, Italian and UK markets. This IWP will analyze the
internationalization into France. To do so, an analysis and explanation of the attractiveness of
this new market is included further along in this paper. It will be seen that despite the fierce
competition that TechFrame will face in France, it will still be an attractive market to enter due
to its’ large size and growing Industrial Property culture among organizations.
Based on that analysis it will be concluded that the best way to enter the French market is
through the creation of an office, and some recommendations will also be made such as
conquering first the SMEs then the larger firms and also the development of the Design
Module
On the notion of phase in mechanics
The notion of phase plays an esential role in both classical and quantum
mechanics.But what is a phase? We show that if we define the notion of phase in
phase (!) space one can very easily and naturally recover the Heisenberg-Weyl
formalism; this is achieved using the properties of the Poincare-Cartan
invariant, and without making any quantum assumption
Transferring Water and Climate Resilience Lessons from Australia\u27s Millennium Drought to Southern California
Southern California and Southern Australia are two regions of the world which share many climatic, socioeconomic and demographic characteristics that lend themselves to meaningful exchanges of knowledge and innovations. With the benefit of Australia’s documented experiences, California can learn what solutions worked and did not work in Australia, potentially avoiding major pitfalls. While some changes in California are already underway, many opportunities – and challenges – still remain. California’s policymakers and residents can adopt and adapt the most fitting solutions from Australia’s experience. California, and especially Southern California, can use these to appropriately and effectively respond to the extremes of our long-term water and climate crises. In doing so, we will put California on a better path towards resilience as we navigate the challenges of drought, flood and extreme heat forecast to increase in our future.
In October 2014, TreePeople and The Energy Coalition co-organized and co-led a delegation of policymakers and elected officials from throughout California to the Australian cities of Melbourne and Adelaide. These cities implemented innovative water management solutions during the Millennium Drought that helped to drought-proof their water supplies and increase resilience in anticipation of a changing climate. The goals of this delegation were to show California water leaders first-hand the drought and climate response initiatives that Adelaide and Melbourne employed and to focus on transferring and implementing viable approaches in California.
This article highlights the key lessons learned from this research and provides recommendations for how Southern California can best approach transferring these lessons
Intersections of Lagrangian submanifolds and the Mel'nikov 1-form
We make explicit the geometric content of Mel'nikov's method for detecting
heteroclinic points between transversally hyperbolic periodic orbits. After
developing the general theory of intersections for pairs of family of
Lagrangian submanifolds constrained to live in an auxiliary family of
submanifolds, we explain how the heteroclinic orbits are detected by the zeros
of the Mel'nikov 1 -form. This 1 -form admits an integral expression, which is
non-convergent in general. Finally, we discuss different solutions to this
convergence problem.Comment: Corrected typos, modified title, updated bibliograph
Stability criterion for bright solitary waves of the perturbed cubic-quintic Schroedinger equation
The stability of the bright solitary wave solution to the perturbed
cubic-quintic Schroedinger equation is considered. It is shown that in a
certain region of parameter space these solutions are unstable, with the
instability being manifested as a small positive eigenvalue. Furthermore, it is
shown that in the complimentary region of parameter space there are no small
unstable eigenvalues. The proof involves a novel calculation of the Evans
function, which is of interest in its own right. As a consequence of the
eigenvalue calculation, it is additionally shown that N-bump bright solitary
waves bifurcate from the primary wave.Comment: 28 pages, LaTeX, submitted; author info at
http://www.math.unm.edu/~kapitul
Documentaries: Both Informing and Entertaining New Zealanders
Interview by Laurence Weinstein of William De Friez and Veronica McCarthy, owners of Raconteur Productions in New Zealand.
William (“Bill”) De Friez and Veronica (“Ronni”) McCarthy own and operate Raconteur Film and Television Productions located in downtown Christchurch. Bill serves as part-time director; his full-time position is faculty lecturer in the Film Department of the University of Canterbury. Ronni is the full-time producer for their small business operation that completes an average of three documentaries per year as well as a network children’s series and other special projects. She won the prestigious Winston Churchill Fellowship in 1995 to study children’s television outside of New Zealand
Three-body confinement force in a realistic constituent quark model
We show that in realistic constituent quark models based on a two-body
confinement interaction color states appear in the middle of the experimentally
known spectrum. To avoid this situation we implement a three-body confinement
interaction, introduced on an algebraic basis, into a semirelativistic version
of the Goldstone-boson-exchange constituent quark model and by solving the
Faddeev equations we show that this interaction can increase the gap between
singlet and colour states, such as the latter can be ignored and the known
baryons can be described as systems. We analyze the effect of a -
and a Y-shape three-body interaction.Comment: 14 pages, 3 figures, revised version to appear in Nucl. Phys.
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