6,016 research outputs found
Loop representation of charged particles interacting with Maxwell and Chern-Simons fields
The loop representation formulation of non-relativistic particles coupled
with abelian gauge fields is studied. Both Maxwell and Chern-Simons
interactions are separately considered. It is found that the loop-space
formulations of these models share significant similarities, although in the
Chern-Simons case there exists an unitary transformation that allows to remove
the degrees of freedom associated with the paths. The existence of this
transformation, which allows to make contact with the anyonic interpretation of
the model, is subjected to the fact that the charge of the particles be
quantized. On the other hand, in the Maxwell case, we find that charge
quantization is necessary in order to the geometric representation be
consistent.Comment: 6 pages, improved versio
Living bacteria rheology: population growth, aggregation patterns and cooperative behaviour under different shear flows
The activity of growing living bacteria was investigated using real-time and
in situ rheology -- in stationary and oscillatory shear. Two different strains
of the human pathogen Staphylococcus aureus -- strain COL and its isogenic cell
wall autolysis mutant -- were considered in this work. For low bacteria
density, strain COL forms small clusters, while the mutant, presenting
deficient cell separation, forms irregular larger aggregates. In the early
stages of growth, when subjected to a stationary shear, the viscosity of both
strains increases with the population of cells. As the bacteria reach the
exponential phase of growth, the viscosity of the two strains follow different
and rich behaviours, with no counterpart in the optical density or in the
population's colony forming units measurements. While the viscosity of strain
COL keeps increasing during the exponential phase and returns close to its
initial value for the late phase of growth, where the population stabilizes,
the viscosity of the mutant strain decreases steeply, still in the exponential
phase, remains constant for some time and increases again, reaching a constant
plateau at a maximum value for the late phase of growth. These complex
viscoelastic behaviours, which were observed to be shear stress dependent, are
a consequence of two coupled effects: the cell density continuous increase and
its changing interacting properties. The viscous and elastic moduli of strain
COL, obtained with oscillatory shear, exhibit power-law behaviours whose
exponent are dependent on the bacteria growth stage. The viscous and elastic
moduli of the mutant have complex behaviours, emerging from the different
relaxation times that are associated with the large molecules of the medium and
the self-organized structures of bacteria. These behaviours reflect
nevertheless the bacteria growth stage.Comment: 9 pages, 10 figure
A Geometric Approach to Massive p-form Duality
Massive theories of abelian p-forms are quantized in a generalized
path-representation that leads to a description of the phase space in terms of
a pair of dual non-local operators analogous to the Wilson Loop and the 't
Hooft disorder operators. Special atention is devoted to the study of the
duality between the Topologically Massive and the Self-Dual models in 2+1
dimensions. It is shown that these models share a geometric representation in
which just one non local operator suffices to describe the observables.Comment: 26 pages, LaTeX. The discussion about the equivalence between the
Proca model and two seldual models, with opposite spins, was eliminated.
Typos correcte
Gender Responsiveness: The Municipality of San Mateo Case
This study assessed the level of responsiveness of the Municipality of San Mateo. Descriptive statistics was employed particularly mean in order to obtain the ratings with regard to the level of gender responsiveness. Frequency counts and percentages were also used in determining the profile of LGU San Mateo. It was found out that the socio-economic data of LGU San Mateo provide information in relation to gender-responsiveness and the LGU has the capacity to deliver and employ gender responsive services which were manifested in its systematic approach and moving towards advanced stages of being gender-responsive. Moreover, mechanisms and strategies could be adopted to facilitate the localization of GAD mainstreaming.
Keywords: basic services, gender, gender responsivenes
The European Union and its energy security challenges: engagement through and with networks
Energy security remains a vital issue for the European Union (EU), even more so in the
wake of the events that unfolded in early 2014 in Ukraine. The EU’s already fragile
position in the international energy arena in terms of security of supply appears to be
more uncertain than ever after its umpteenth fallout with its historic energy supplier,
Russia. This situation is untenable and calls for swift and decisive action to adequately
tackle the issue once and for all. The article looks at the creation of a single EU energy
market through integration of energy networks in the EU. It then examines various
ways to diversify the EU’s energy supply, whether through increasing the import of
liquefied natural gas, through its relations with the Eurasian Union, the promotion of
renewable energy or the construction of alternative pipelines and energy routes. The
article then offers an analysis of the latest developments of the Energy Charter
Conference. The article concludes that from energy transit, to technology transfer,
to investment protection, energy and trade present interplays across various fields.
Improvements can be made to the EU trading system to ensure greater energy security
and more efficient energy markets
Interacting Particles and Strings in Path and Surface Representations
Non-relativistic charged particles and strings coupled with abelian gauge
fields are quantized in a geometric representation that generalizes the Loop
Representation. We consider three models: the string in self-interaction
through a Kalb-Ramond field in four dimensions, the topological interaction of
two particles due to a BF term in 2+1 dimensions, and the string-particle
interaction mediated by a BF term in 3+1 dimensions. In the first case one
finds that a consistent "surface-representation" can be built provided that the
coupling constant is quantized. The geometrical setting that arises corresponds
to a generalized version of the Faraday's lines picture: quantum states are
labeled by the shape of the string, from which emanate "Faraday`s surfaces". In
the other models, the topological interaction can also be described by
geometrical means. It is shown that the open-path (or open-surface) dependence
carried by the wave functional in these models can be eliminated through an
unitary transformation, except by a remaining dependence on the boundary of the
path (or surface). These feature is closely related to the presence of
anomalous statistics in the 2+1 model, and to a generalized "anyonic behavior"
of the string in the other case.Comment: RevTeX 4, 28 page
Maxwell Chern Simons Theory in a Geometric Representation
We quantize the Maxwell Chern Simons theory in a geometric representation
that generalizes the Abelian Loop Representation of Maxwell theory. We find
that in the physical sector, the model can be seen as the theory of a massles
scalar field with a topological interaction that enforces the wave functional
to be multivalued. This feature allows to relate the Maxwell Chern Simons
theory with the quantum mechanics of particles interacting through a Chern
Simons fieldComment: 12 pages, LaTe
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