6,971 research outputs found
On the Reduced SU(N) Gauge Theory in the Weyl-Wigner-Moyal Formalism
Weyl-Wigner-Moyal formalism is used to describe the large- limit of
reduced SU quenching gauge theory. Moyal deformation of Schild-Eguchi
action is obtained.Comment: 24 pages, phyzzx file, no figures, version to appear in Int. J. Mod.
Phys.
Using choreographies to support the gamification process on the development of an application to reduce electricity costs
Building automation systems contribute to reduce electricity costs by managing distributed energy resources in an efficient way. However, a large share of consumption cannot be optimized through automation alone, since it mainly depends on human interactions. Gamification can be used as one form of changing users’ behaviours [1], but its implementation does require assumptions on the behaviour patterns that need to
be identified, encouraged, or discouraged. To tackle this problem, we propose a framework that joins building automation solutions with gamification techniques to enable behavioural demand response.info:eu-repo/semantics/publishedVersio
Substructure analysis of the bacterial antenna LH II by nonlinear polarization spectroscopy in the frequency domain
Light Propagation in Inhomogeneous Universes. IV. Strong Lensing and Environmental Effects
We study the gravitational lensing of high-redshift sources in a LCDM
universe. We have performed a series of ray-tracing experiments, and selected a
subsample of cases of strong lensing (multiple images, arcs, and Einstein
rings). For each case, we identify a massive galaxy that is primarily
responsible for lensing, and studied how the various density inhomogeneities
along the line of sight (other galaxies, background matter) affect the
properties of the image. The matter located near the lensing galaxy, and
physically associated with it, has a small effect. The background matter
increases the magnification by a few percents at most, while nearby galaxies
can increase it by up to about 10 percent. The effect on the image separation
is even smaller. The only significant effect results from the random alignment
of physically unassociated galaxies, which can increase the magnification by
factors of several, create additional images, and turn arcs into rings. We
conclude that the effect of environment on strong lensing in negligible in
general, and might be important only in rare cases. We show that our conclusion
does not depend on the radial density profile of the galaxies responsible for
lensing.Comment: 23 pages, 7 figures (one in color). Accepted for publication in The
Astrophysical Journal. Minor typos correcte
A confirmed location in the Galactic halo for the high-velocity cloud 'chain A'
The high-velocity clouds of atomic hydrogen, discovered about 35 years ago,
have velocities inconsistent with simple Galactic rotation models that
generally fit the stars and gas in the Milky Way disk. Their origins and role
in Galactic evolution remain poorly understood, largely for lack of information
on their distances. The high-velocity clouds might result from gas blown from
the Milky Way disk into the halo by supernovae, in which case they would enrich
the Galaxy with heavy elements as they fall back onto the disk. Alternatively,
they may consist of metal-poor gas -- remnants of the era of galaxy formation,
accreted by the Galaxy and reducing its metal abundance. Or they might be truly
extragalactic objects in the Local Group of galaxies. Here we report a firm
distance bracket for a large high-velocity cloud, Chain A, which places it in
the Milky Way halo (2.5 to 7 kiloparsecs above the Galactic plane), rather than
at an extragalactic distance, and constrains its gas mass to between 10^5 and 2
times 10^6 solar masses.Comment: 8 pages, including 4 postscript figures. Letter to Nature, 8 July
199
Reality conditions for Ashtekar variables as Dirac constraints
We show that the reality conditions to be imposed on Ashtekar variables to
recover real gravity can be implemented as second class constraints a la Dirac.
Thus, counting gravitational degrees of freedom follows accordingly. Some
constraints of the real theory turn out to be non-polynomial, regardless of the
form, polynomial or non-polynomial, taken for the reality conditions. We
comment upon the compatibility of our approach with the recently proposed Wick
transform point of view, as well as on some alternatives for dealing with such
second class constraints.Comment: 16 pages, plain LaTeX, submitted to Class. Quant. Grav. E-mail:
[email protected]
Alguns contributos da nanotecnologia para a sustentabilidade dos materiais de construção
Os avanços nanotecnológicos atingem inúmeras áreas da ciência, mas no âmbito da sustentabilidade dos materiais de construção os progressos embora importantes são escassos e acima de tudo objeto de reduzida divulgação. O presente artigo sintetiza uma avaliação do
estado da arte relativa a alguns dos contributos da nanotecnologia para a sustentabilidade dos materiais de construção. No mesmo se aborda a compreensão dos compostos gerados durante a hidratação do cimento Portland, o aumento da resistência e da durabilidade de argamassas e betões pela adição de nanopartículas e nanotubos e de que forma a adição de nanopartículas pode contribuir para a autolimpeza, a purificação do ar e a capacidade bactericida em materiais
construtivos por via do efeito fotocatalítico. O presente artigo aborda ainda os últimos
desenvolvimentos da nanotecnologia com vista à eficiência energética, nomeadamente pela produção de isolamentos térmicos de elevado desempenho, janelas com baixa condutibilidade térmica, vidros com transmitância variável e materiais de mudança de fase mais eficientes
Mass & secondary structure propensity of amino acids explain their mutability and evolutionary replacements
Why is an amino acid replacement in a protein accepted during evolution? The answer given by bioinformatics relies on the frequency of change of each amino acid by another one and the propensity of each to remain unchanged. We propose that these replacement rules are recoverable from the secondary structural trends of amino acids. A distance measure between high-resolution Ramachandran distributions reveals that structurally similar residues coincide with those found in substitution matrices such as BLOSUM: Asn Asp, Phe Tyr, Lys Arg, Gln Glu, Ile Val, Met → Leu; with Ala, Cys, His, Gly, Ser, Pro, and Thr, as structurally idiosyncratic residues. We also found a high average correlation (\overline{R} R = 0.85) between thirty amino acid mutability scales and the mutational inertia (I X ), which measures the energetic cost weighted by the number of observations at the most probable amino acid conformation. These results indicate that amino acid substitutions follow two optimally-efficient principles: (a) amino acids interchangeability privileges their secondary structural similarity, and (b) the amino acid mutability depends directly on its biosynthetic energy cost, and inversely with its frequency. These two principles are the underlying rules governing the observed amino acid substitutions. © 2017 The Author(s)
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