2,261 research outputs found
Composite MFV and Beyond
We revisit and extend realizations of Minimal Flavor Violation (MFV) in
theories with strongly coupled electro-weak symmetry breaking. MFV requires
that some chiralities of light SM quarks are strongly composite leading,
depending on the scenario, to bounds from compositeness searches, precision
electro-weak tests or even flavor physics. Within the framework of partial
compositeness we show how to extend the MFV paradigm allowing the treat the top
quark differently. This can be realized if for example the strong sector has an
U(2) symmetry. In this case the light generations can be mostly elementary and
all the bounds are easily satisfied.Comment: 16 pages. v2) estimates improved, conclusions unchange
Modelling human factors in perceptual multimedia quality: On the role of personality and culture
Perception of multimedia quality is shaped by a rich interplay between system, context, and human factors. While system and context factors are widely researched, few studies in this area consider human factors as sources of systematic variance. This paper presents an analysis on the influence of personality (Five-Factor Model) and cultural traits (Hofstede Model) on the perception of multimedia quality. A set of 144 video sequences (from 12 short movie excerpts) were rated by 114 participants from a cross-cultural population, producing 1232 ratings. On this data, three models are compared: a baseline model that only considers system factors; an extended model that includes personality and culture as human factors; and an optimistic model in which each participant is modeled as a random effect. An analysis shows that personality and cultural traits represent 9.3% of the variance attributable to human factors while human factors overall predict an equal or higher proportion of variance compared to system factors. In addition, the quality-enjoyment correlation varied across the movie excerpts. This suggests that human factors play an important role in perceptual multimedia quality, but further research to explore moderation effects and a broader range of human factors is warranted
Geophysics
Contains reports on four research projects.United States Air Force (Contract AF19(628)-500)Lincoln Laboratory (Purchase Order DDL BB-107
Axion-Higgs Unification
In theories with no fundamental scalars, one gauge group can become strong at
a large scale Lambda and spontaneously break a global symmetry, producing the
Higgs and the axion as composite pseudo-Nambu-Goldstone bosons. We show how
KSVZ and DFSZ axion models can be naturally realised. The assumption Lambda
around 10^{11} GeV is phenomenologically favoured because: a) The axion solves
the QCD theta problem and provides the observed DM abundance; b) The observed
Higgs mass is generated via RGE effects from a small Higgs quartic coupling at
the compositeness scale, provided that the Higgs mass term is fine-tuned to be
of electroweak size; c) Lepton, quark as well as neutrino masses can be
obtained from four-fermion operators at the compositeness scale. d) The extra
fermions can unify the gauge couplings.Comment: 19 pages. Refs. added and eq. 3.6 fixe
Assessing molecular diversity among 87 species of the Quercus L. genus by RAPD markers
Oaks (Quercus sp.) are among the most ecologically and economically important woody Angiosperms of the northern hemisphere. Nowadays, the reduction of Quercus biodiversity is becoming a matter of global concern, and several oak species have been included in the IUCN Red List of Threatened Species. Consequently, characterization and preservation strategies for the oak germplasm are largely promoted. Thus, in this work, the genetic diversity existing among 87 different Quercus species was assessed using the RAPD markers, in order to better typify these specimens, to show the amazing DNA variability of this plant genus, and to confirm or infer new putative molecular correlations. Our data were discussed taking into consideration the phylogenetic and phylogeographic relationships previously proposed by the literature. In general, the obtained results corroborated that the evolutionary pattern of Quercus genus has been extremely intricate and continues to change rapidly, making it difficult to be fully resolved. The evidence collected in the present investigation would confirm the complex evolution of the oaks, due to their high migration capacity, divergence rate, and hybridization propensity. This research, performed on a so large series of species, represents a positive contribution for highlighting the genetic diversity within collections of Quercus germplasm and favouring ex-situ conservation programmes
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