616 research outputs found
Maurer-Cartan Equations and Black Hole Superpotentials in N =8 Supergravity
We retrieve the non-BPS extremal black hole superpotential of N=8, d=4
supergravity by using the Maurer-Cartan equations of the symmetric space
E_7(7)/SU(8). This superpotential was recently obtained with different 3- and
4-dimensional techniques. The present derivation is independent on the
reduction to d=3.Comment: 1+22 page
"Root" Action for N=4 Supersymmetric Mechanics Theories
We propose to consider the N=4,d=1 supermultiplet with $% (4,4,0) component
content as a ``root'' one. We elaborate a new reduction scheme from the
``root'' multiplet to supermultiplets with a smaller number of physical bosons.
Starting from the most general sigma-model type action for the ``root''
multiplet, we explicitly demonstrate that the actions for the rest of linear
and nonlinear N=4 supermultiplets can be easily obtained by reduction.
Within the proposed reduction scheme there is a natural possibility to
introduce Fayet-Iliopoulos terms. In the reduced systems, such terms give rise
to potential terms, and in some cases also to terms describing the interaction
with a magnetic field.
We demonstrate that known N=4 superconformal actions, together with their
possible interactions, appear as results of the reduction from a free action
for the ``root'' supermultiplet. As a byproduct, we also construct an N=4
supersymmetric action for the linear (3,4,1) supermultiplet, containing both an
interaction with a Dirac monopole and a harmonic oscillator-type potential,
generalized for arbitrary conformally flat metrics.Comment: 12 page
Desarrollo del SOB
El objetivo general del trabajo de Tesis consiste en generar una propuesta para potenciar el desarrollo económico del SOB, a través de conocer la conformación e importancia de los sectores económicos de la región, identificar los encadenamientos productivos y el intercambio comercial actual y potencial.Área: Ciencias Sociales y Humanas
First Order Description of D=4 static Black Holes and the Hamilton-Jacobi equation
In this note we discuss the application of the Hamilton-Jacobi formalism to
the first order description of four dimensional spherically symmetric and
static black holes. In particular we show that the prepotential characterizing
the flow coincides with the Hamilton principal function associated with the
one-dimensional effective Lagrangian. This implies that the prepotential can
always be defined, at least locally in the radial variable and in the moduli
space, both in the extremal and non-extremal case and allows us to conclude
that it is duality invariant. We also give, in this framework, a general
definition of the ``Weinhold metric'' in terms of which a necessary condition
for the existence of multiple attractors is given. The Hamilton-Jacobi
formalism can be applied both to the restricted phase space where the
electromagnetic potentials have been integrated out as well as in the case
where the electromagnetic potentials are dualized to scalar fields using the
so-called three-dimensional Euclidean approach. We give some examples of
application of the formalism, both for the BPS and the non-BPS black holes.Comment: A clarifying discussion on the existence of the prepotential and a
comment on multiple attractors are added; typos corrected, references adde
N=4 supersymmetric mechanics with nonlinear chiral supermultiplet
We construct N=4 supersymmetric mechanics using the N=4 nonlinear chiral
supermultiplet. The two bosonic degrees of freedom of this supermultiplet
parameterize the sphere S(2) and go into the bosonic components of the standard
chiral multiplet when the radius of the sphere goes to infinity. We construct
the most general action and demonstrate that the nonlinearity of the
supermultiplet results in the deformation of the connection, which couples the
fermionic degrees of freedom with the background, and of the bosonic potential.
Also a non-zero magnetic field could appear in the system.Comment: 5 page
HOW TO EXTRACT USEFUL INFORMATION ABOUT THE DECAY OF BASS RELIEVES IN ARCHAEOLOGICAL AREA
Abstract. Cultural Heritage goods represent the memory and the history of the civilization. Notwithstanding, there are not sufficient public resources to guarantee their preservation and maintenance. Nowadays between several geomatic techniques available, the pillar for the preservation of mankinds heritage is the low cost close photogrammetric acquisition. The advantages of virtual reconstructions based on Multi View Stereo (MVS) and Structure from Motion (SfM) algorithms is extended from the heritage documentation to its virtualization or modelling. The digital preservation of archaeological sites is committed in more agile and friendly procedures that give automatic extraction of information to perform in depth analysis over ancient artefacts. In the field of CH research, the characterization and classification of the conservation state of the materials composing the surface of the artefacts are essential to study their damage. The first step for conservation state of a goods is the study of the changes in different times. The possibility to automatically study this time modification due to different factor represents a key point for the archaeologists' work. With this in mind, the aim of this work is to propose a completely automatic methods for change detection between three data set acquired in different époques. The work flow applied is based on the unsupervised clustering techniques applied on a combination of two type of differences images. The results, unlike the objective, demonstrate that the unsupervised methods are not effectiveness in the CH study, instead of the supervised methods that outperforms in terms of reliability of results.</p
N=4 superconformal mechanics in the pp-wave limit
We constructed the pp-wave limit of N=4 superconformal mechanics with the
off-shell multiplet. We present the superfield and the
component actions which exhibit the interesting property that the interaction
parts are completely fixed by the symmetry. We also explicitly demonstrate that
the passing to the pp-wave limit can be achieved by keeping at most quadratic
nonlinearities in the action of (super)conformal mechanics.Comment: 11 pages. We corrected a misprint in the second pair of Eqs. (3.1
Mannitol Does Not Enhance Tobramycin Killing of Pseudomonas aeruginosa in a Cystic Fibrosis Model System of Biofilm Formation
Cystic Fibrosis (CF) is a human genetic disease that results in the accumulation of thick, sticky mucus in the airways, which results in chronic, life-long bacterial biofilm infections that are difficult to clear with antibiotics. Pseudomonas aeruginosa lung infection is correlated with worsening lung disease and P. aeruginosa transitions to an antibiotic tolerant state during chronic infections. Tobramycin is an aminoglycoside currently used to combat lung infections in individuals with CF. While tobramycin is effective at eradicating P. aeruginosa in the airways of young patients, it is unable to completely clear the chronic P. aeruginosa infections in older patients. A recent report showed that co-addition of tobramycin and mannitol enhanced killing of P. aeruginosa grown in vitro as a biofilm on an abiotic surface. Here we employed a model system of bacterial biofilms formed on the surface of CF-derived airway cells to determine if mannitol would enhance the antibacterial activity of tobramycin against P. aeruginosa grown on a more clinically relevant surface. Using this model system, which allows the growth of robust biofilms with high-level antibiotic tolerance analogous to in vivo biofilms, we were unable to find evidence for enhanced antibacterial activity of tobramycin with the addition of mannitol, supporting the observation that this type of co-treatment failed to reduce the P. aeruginosa bacterial load in a clinical setting
The PAMELA Time-of-Flight system: status report
Abstract The PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) satellite-borne experiment, scheduled to be launched in 2003, aboard a Soyuz TM2 rocket, is designed to provide a better understanding of the antimatter component of cosmic rays. In the following we report on the features and performances of its scintillator telescope system which will provide the primary experimental trigger and time-of-flight particle identification
Evaluation of the irradiation treatment effects on ancient parchment samples
In this work, the effect of X-ray irradiation as a disinfection treatment in original ancient parchment samples, belonging to a discarded book cover of a 16th-century archival register, has been evaluated. Specifically, the bacterial and fungal species isolated from the book cover have been characterized and then irradiated with increasing doses of X-rays with the aim to evaluate the effectiveness of the antimicrobial protocol on the isolated microorganisms. The deterioration effects induced by the X-ray treatment as well as the natural aging on the collagen matrix of the parchment sample have been tested by employing several techniques, namely, Light Transmission Analysis, Fiber Optic Reflectance Spectroscopy, Attenuated Total Reflectance-Fourier Transformed Infrared spectroscopy, UV Resonant Raman spectroscopy and Atomic Force Microscopy. The results reveal that the irradiation treatment applied to our ancient parchment samples deteriorated by biological attack and other naturally occurring phenomena, possibly associated with inappropriate conservation conditions, does not seem to induce further damage factors even when large doses of irradiation are employed. The X-rays-based disinfection treatment effects are limited on the collagen support and this confirms the potential of this method in mass disinfection of library and archival materials
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