89,914 research outputs found
CAD of Stacked Patch Antennas Through Multipurpose Admittance Matrices From FEM and Neural Networks
In this work, a novel computer-aided design methodology for probe-fed, cavity-backed, stacked microstrip patch antennas is proposed. The methodology incorporates the rigor of a numerical technique, such as finite element methods, which, in turn, makes use of a newly developed procedure (multipurpose admittance matrices) to carry out a full-wave analysis in a given structure in spite of certain physical shapes and dimensions not yet being established. With the aid of this technique, we form a training set for a neural network, whose output is the desired response of the antenna according to the value of design parameters. Last, taking advantage of this neural network, we perform a global optimization through a genetic algorithm or simulated annealing to obtain a final design. The proposed methodology is validated through a real design whose numerical results are compared with measurements with good agreement
In Defence of No Best World
Recent work in the philosophy of religion has resurrected Leibnizâs idea that there is a best possible world, perhaps ours. In particular, Klaas Kraayâs [2010] construction of a theistic multiverse and Nevin Climenhagaâs [2018] argument from infinite value theory are novel defenses of a best possible world. I do not think that there is a best world, and show how both Kraay and Climenhaga may be resisted. First, I argue that Kraayâs construction of a theistic multiverse can be resisted from plausible assumptions about set theory. Next, I argue against the value-theoretic assumptions that underlie Climenhagaâs argument and show how to give an infinite value theory where there is no best world
Higgs inflation and vacuum stability
Inflation is nowadays a well-established paradigm consistent with all the
observations. The precise nature of the inflaton is however unknown and its
role could be played by any candidate able to imitate a scalar condensate in
the slow-roll regime. The discovery of a fundamental scalar in the LHC provides
the less speculative candidate. Could the Higgs field itself be responsible for
inflation? Do we really need to advocate new physics to explain the properties
of the Universe at large scales? Which is the relation between the Standard
Model parameters and the inflationary observables? What happens if our vacuum
becomes unstable below the scale of inflation? We present an overview of Higgs
inflation trying to provide answers to the previous questions with special
emphasis on the vacuum stability issue.Comment: 11 pages, 14 figures, contribution to proceedings DISCRETE 201
Spectroscopic Properties and STM Images of Carbon Nanotubes
We present a theoretical study of the role of the local environment in the
electronic properties of carbon nanotubes: isolated single- and multi-wall
nanotubes, nanotube-ropes, tubes supported on gold and cutted to finite length.
Interaction with the substrate or with other tubes does not alter the
scanning-tunneling-microscopy (STM) patterns observed for isolated tubes.
STM-topographic images of topological defects (pentagon/heptagon pair) and
tube-caps have also been studied. In both cases the obtained image depends on
the sign of the applied voltage and it can be described in terms of the
previous catalog of STM-images (interference between electronic waves scattered
by the defect). We also have computed the electronic density of states for
isolated tubes with different chiralities and radii confirming a correlation
between the peak-structure in the DOS and the nanotube diameter, however the
metallic plateau in the DOS also depends on the nanotube chirality.
Furthermore, the conduction and valence band structures are not fully
symmetrical to one another. In contrast to STM images, the interaction with the
substrate does modify the energy levels of the nanotube. We observe opening of
small pseudogaps around the Fermi level and broadening of the sharp van Hove
singularities of the isolated single-walled-nanotubes that can be used to
extract useful information about the tube structure and bonding. The
combination of STM and spectroscopic studies opens a new technique to address
the electronic and structural properties of carbon and composite nanotubes.Comment: 9 pages, 8 eps figures. Applied Physics A (in press
On the Gelfand property for complex symmetric pairs
We first prove, for pairs consisting of a simply connected complex reductive
group together with a connected subgroup, the equivalence between two different
notions of Gelfand pairs. This partially answers a question posed by Gross, and
allows us to use a criterion due to Aizenbud and Gourevitch, and based on
Gelfand-Kazhdan's theorem, to study the Gelfand property for complex symmetric
pairs. This criterion relies on the regularity of the pair and its descendants.
We introduce the concept of a pleasant pair, as a means to prove regularity,
and study, by recalling the classification theorem, the pleasantness of all
complex symmetric pairs. On the other hand, we prove a method to compute all
the descendants of a complex symmetric pair by using the extended Satake
diagram, which we apply to all pairs. Finally, as an application, we prove that
eight out of the twelve exceptional complex symmetric pairs, together with the
infinite family , satisfy the
Gelfand property, and state, in terms of the regularity of certain symmetric
pairs, a sufficient condition for a conjecture by van Dijk and a reduction of a
conjecture by Aizenbud and Gourevitch.Comment: Presentation and arguments improved in Sections 5.1 and 5.2. Typos
and small mistakes fixe
Novel polyhydroxyalkanoate beads for use as a vaccine against tuberculosis : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Microbiology at Massey University, Manawatƫ, New Zealand
Tuberculosis was in 1993 declared as a re-emerging disease by the World Health
Organization. The only vaccine currently available, BCG, an attenuated strain of
Mycobacterium bovis, does not protect adults against the pulmonary disease, which is the
form of transmission. New vaccine candidates are being developed to provide protection
against tuberculosis. Subunit vaccines offer a safer alternative than whole cell preparations
and provide the possibility of utilizing only the components that mediate protective immune
responses. This thesis describes the production of bacterially derived polyhydroxyalkanoate
(PHA) beads for use as a delivery system for Mycobacterium tuberculosis reverse
vaccinology antigens and immune modulators.
In the first study, the immunogenicity of beads derived from an endotoxin-free host, Clear
coli, displaying M. tuberculosis antigens Rv1626, Rv2032 and Rv1789 was evaluated in
mice. Beads displaying Rv1626 were selected for further studies based on the magnitude
and specificity of the immune response elicited. In a final study, the immune modulators
Cpe30, CS.T3378-395 and Flagellin were co-displayed with Rv1626 antigen on beads and the
immunogenicity of these functionalised beads evaluated in mice. Vaccinations with Rv1626
beads and the immune modulators Cpe30 and CS. T3378-395 induced a Th1/Th17 skewed
immune response. These beads were then assessed for their ability to protect mice against
aerosol challenge with Mycobacterium bovis. Rv1626 beads reduced the bacterial loads in
0.48 log10 compared with the negative control group but the inclusion of immune modulators
did not enhance the immunogenicity or protection induced by Rv1626 beads.
This study has demonstrated the potential of PHA beads delivering a single reverse
vaccinology antigen for protection against tuberculosis infection in mice. While the co-display
of immune modulators did not improve the protection induced by the antigen, further studies
are needed to determine optimal doses for delivery of immune modulators to enhance
protective immunity
Women in Europe and in the world: The state of the Union 2016
Building on the definition of oppression developed by the philosopher Iris Young, the article
argues that women in Europe are an oppressed group. Relying on recent statistics, it points out
that a high percentage of women are still subject to gender violence; economically exploited and
marginalized; powerless with regard to governance and participation in the public sphere, as
well as victims of androcentrismâa pattern of cultural evaluation which seriously undermines
womenâs potential for development. The article then shows how this state of affairs has worsened
over the last years, under the effects of the financial and economic crisis, and the austerity policies
with which the European states have responded. Finally, it singles out two possible future
scenarios. If the current neo-liberal trends persist, we can expect a move towards societies more
polarized in terms of class and ethnicity; low fertility rates; and an increasing poverty of those
most in need of care and in charge of care provision. The crisis could instead be perceived as an
opportunity to diverge from this prevailing neo-liberal model, calling for a new, inclusive, societal
model of developmentâa new humanism which puts the person, in her whole complexity and in
her very real care dependent nature, at the very core of the political and economic project
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