1,348 research outputs found
Fermion masses in noncommutative geometry
Recent indications of neutrino oscillations raise the question of the
possibility of incorporating massive neutrinos in the formulation of the
Standard Model (SM) within noncommutative geometry (NCG). We find that the NCG
requirement of Poincare duality constrains the numbers of massless quarks and
neutrinos to be unequal unless new fermions are introduced. Possible scenarios
in which this constraint is satisfied are discussed.Comment: 4 pages, REVTeX; typos are corrected in (19), "Possible Solutions"
and "Conclusion" are modified; additional calculational details are included;
references are update
Fine-tuning the functional properties of carbon nanotubes via the interconversion of encapsulated molecules
Tweaking the properties of carbon nanotubes is a prerequisite for their
practical applications. Here we demonstrate fine-tuning the electronic
properties of single-wall carbon nanotubes via filling with ferrocene
molecules. The evolution of the bonding and charge transfer within the tube is
demonstrated via chemical reaction of the ferrocene filler ending up as
secondary inner tube. The charge transfer nature is interpreted well within
density functional theory. This work gives the first direct observation of a
fine-tuned continuous amphoteric doping of single-wall carbon nanotubes
Mouse models for studying prostate cancer bone metastasis.
Once tumor cells metastasize to the bone, the prognosis for prostate cancer patients is generally very poor. The mechanisms involved in bone metastasis, however, remain elusive, because of lack of relevant animal models. In this manuscript, we describe step-by-step protocols for the xenograft mouse models that are currently used for studying prostate cancer bone metastasis. The different routes of tumor inoculation (intraosseous, intracardiac, intravenous and orthotopic) presented are useful for exploring the biology of bone metastasis
Minimal Trinification
We study the trinified model, SU(3)_C x SU(3)_L x SU(3)_R x Z_3, with the
minimal Higgs sector required for symmetry breaking. There are five Higgs
doublets, and gauge-coupling unification results if all five are at the weak
scale, without supersymmetry. The radiative see-saw mechanism yields sub-eV
neutrino masses, without the need for intermediate scales, additional Higgs
fields, or higher-dimensional operators. The proton lifetime is above the
experimental limits, with the decay modes p -> \bar\nu K^+ and p -> \mu^+ K^0
potentially observable. We also consider supersymmetric versions of the model,
with one or two Higgs doublets at the weak scale. The radiative see-saw
mechanism fails with weak-scale supersymmetry due to the nonrenormalization of
the superpotential, but operates in the split-SUSY scenario.Comment: 23 pages, uses axodra
On the complementarity of Hyper-K and LBNF
The next generation of long-baseline experiments is being designed to make a
substantial step in the precision of measurements of neutrino-oscillation
probabilities. Two qualitatively different proposals, Hyper-K and LBNF, are
being considered for approval. This document outlines the complimentarity
between Hyper-K and LBNF.Comment: 5 pager
Initial report from the ICFA Neutrino Panel
In July 2013 ICFA established the Neutrino Panel with the mandate "To promote
international cooperation in the development of the accelerator-based
neutrino-oscillation program and to promote international collaboration in the
development a neutrino factory as a future intense source of neutrinos for
particle physics experiments". This, the Panel's Initial Report, presents the
conclusions drawn by the Panel from three regional "Town Meetings" that took
place between November 2013 and February 2014.
After a brief introduction and a short summary of the status of the knowledge
of the oscillation parameters, the report summarises the approved programme and
identifies opportunities for the development of the field. In its conclusions,
the Panel recognises that to maximise the discovery potential of the
accelerator-based neutrino-oscillation programme it will be essential to
exploit the infrastructures that exist at CERN, FNAL and J-PARC and the
expertise and resources that reside in laboratories and institutes around the
world. Therefore, in its second year, the Panel will consult with the
accelerator-based neutrino-oscillation community and its stakeholders to:
develop a road-map for the future accelerator-based neutrino-oscillation
programme that exploits the ambitions articulated at CERN, FNAL and J-PARC and
includes the programme of measurement and test-beam exposure necessary to
ensure the programme is able to realise its potential; develop a proposal for a
coordinated "Neutrino RD" programme, the accelerator and detector R&D programme
required to underpin the next generation of experiments; and to explore the
opportunities for the international collaboration necessary to realise the
Neutrino Factory.Comment: ICFA Neutrino Panel 2014(01
Influence of Introgression and Geological Processes on Phylogenetic Relationships of Western North American Mountain Suckers (Pantosteus, Catostomidae)
Intense geological activity caused major topographic changes in Western North America over the past 15 million years. Major rivers here are composites of different ancient rivers, resulting in isolation and mixing episodes between river basins over time. This history influenced the diversification of most of the aquatic fauna. The genus Pantosteus is one of several clades centered in this tectonically active region. The eight recognized Pantosteus species are widespread and common across southwestern Canada, western USA and into northern Mexico. They are typically found in medium gradient, middle-elevation reaches of rivers over rocky substrates. This study (1) compares molecular data with morphological and paleontological data for proposed species of Pantosteus, (2) tests hypotheses of their monophyly, (3) uses these data for phylogenetic inferences of sister-group relationships, and (4) estimates timing of divergence events of identified lineages. Using 8055 base pairs from mitochondrial DNA protein coding genes, Pantosteus and Catostomus are reciprocally monophyletic, in contrast with morphological data. The only exception to a monophyleticPantosteus is P. columbianus whose mtDNA is closely aligned with C. tahoensis because of introgression. Within Pantosteus, several species have deep genetic divergences among allopatric sister lineages, several of which are diagnosed and elevated to species, bringing the total diversity in the group to 11 species. Conflicting molecular and morphological data may be resolved when patterns of divergence are shown to be correlated with sympatry and evidence of introgression
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