1,660 research outputs found
Pseudo Goldstone Bosons Phenomenology in Minimal Walking Technicolor
We construct the non-linear realized Lagrangian for the Goldstone Bosons
associated to the breaking pattern of SU(4) to SO(4). This pattern is expected
to occur in any Technicolor extension of the standard model featuring two Dirac
fermions transforming according to real representations of the underlying gauge
group. We concentrate on the Minimal Walking Technicolor quantum number
assignments with respect to the standard model symmetries. We demonstrate that
for, any choice of the quantum numbers, consistent with gauge and Witten
anomalies the spectrum of the pseudo Goldstone Bosons contains electrically
doubly charged states which can be discovered at the Large Hadron Collider.Comment: 25 pages, 5 figure
First Principles Simulations of Boron Diffusion in Graphite
Boron strongly modifies electronic and diffusion properties of graphite. We report the first ab initio study of boron interaction with the point defects in graphite, which includes structures, thermodynamics, and diffusion. A number of possible diffusion mechanisms of boron in graphite are suggested. We conclude that boron diffuses in graphite by a kick-out mechanism. This mechanism explains the common activation energy, but large magnitude difference, for the rate of boron diffusion parallel and perpendicular to the basal plane. © 2007 The American Physical Society
Free monadic Tarski and MMI3-algebras
MMI3-algebras are a generalization of the monadic Tarski algebras as defined by A. Monteiro and L. Iturrioz, and a particular case of the MMIn+1-algebras defined by A. Figallo. They can also be seen as monadic three-valued ÂŁukasiewicz algebras without a first element. By using this point of view, and the free monadic extensions, we construct the free MMI3-algebras on a finite number of generators, and indicate the coordinates of the generators. As a byproduct, we also obtain a construction of the free monadic Tarski algebras.Fil: Entizne, Rosana V.. Universidad Nacional del Sur. Departamento de Matemática; ArgentinaFil: Monteiro, Luiz F.. Universidad Nacional del Sur. Departamento de Matemática; ArgentinaFil: Savini, Sonia M.. Universidad Nacional del Sur. Departamento de Matemática; ArgentinaFil: Viglizzo, Ignacio Dario. Universidad Nacional del Sur. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca; Argentin
Transplacental transmission of field and rescued strains of BTV-2 and BTV-8 in experimentally infected sheep
Transplacental transmission of bluetongue virus has been shown previously for the North European strain of serotype 8 (BTV-8) and for tissue culture or chicken egg-adapted vaccine strains but not for field strains of other serotypes. In this study, pregnant ewes (6 per group) were inoculated with either field or rescued strains of BTV-2 and BTV-8 in order to determine the ability of these viruses to cross the placental barrier. The field BTV-2 and BTV-8 strains was passaged once in Culicoides KC cells and once in mammalian cells. All virus inoculated sheep became infected and seroconverted against the different BTV strains used in this study. BTV RNA was detectable in the blood of all but two ewes for over 28Â days but infectious virus could only be detected in the blood for a much shorter period. Interestingly, transplacental transmission of BTV-2 (both field and rescued strains) was demonstrated at high efficiency (6 out of 13 lambs born to BTV-2 infected ewes) while only 1 lamb of 12 born to BTV-8 infected ewes showed evidence of in utero infection. In addition, evidence for horizontal transmission of BTV-2 between ewes was observed. As expected, the parental BTV-2 and BTV-8 viruses and the viruses rescued by reverse genetics showed very similar properties to each other. This study showed, for the first time, that transplacental transmission of BTV-2, which had been minimally passaged in cell culture, can occur; hence such transmission might be more frequent than previously thought
Specific interaction of plant HMG-like proteins with cruciform DNA
Proteins which, on the basis of their solubility in 0.35% NaCl-2% TCA and of their electrophoretic mobility, correspond to animal HMG 1/2 family were isolated from nuclei of ungerminated pea embryos. These proteins ound with a high degree of specificity to synthetic cruciform DNA produced by annealing chemically synthesized oligonucleotides. Hence, specific binding to four-way junction DNA, previously reported for animal HMG 1 and 2 proteins proved also to be a property of plant HMG 1/2 family, in spite of their low homology to the animal ones
Landscapes and Landforms of Terrestrial and Marine Areas: A Way Forward
The article introduces the aims and topics of the Special Issue 'Landscapes and Landforms of Terrestrial and Marine Areas' showing a variety of approaches and techniques used to integrate terrestrial and marine spatial datasets. The outcomes not only show how innovative and advanced geomorphological mapping techniques can support a more informed sustainable management of coastal environments, but also pave the way for other studies that rely on an improved efficiency in providing 3D landscape visualization from remote multisource and multiscale data
The Social Appraisal of Techno-Experiments: Whirlpools and Mosaics of Smart Urbanism
Technology-driven experiments—techno-experiments—have become a central mode of spatial intervention in a paradigm of smart growth. They are often considered a manifestation of a techno-managerial approach to governance, built upon the increasing influence of IT corporations on urban politics. Yet, there is little evidence indicating how these interests articulate techno-experiments and shape their legacies over the long run. This paper questions the varied politics of techno-experiments by comparing four projects in Stockholm and Amsterdam: two smart energy grid pilots and two online community-based platforms. Mobilizing the notion of the “social appraisal of technology,” it argues that techno-experiments can take different forms depending on how the role of digital technology is defined and negotiated by actors throughout the process of experimentation. The paper empirically shows that experiments can evolve in two main ways, defined as “whirlpools” and “mosaics.” As whirlpools, they upscale self-referentially; as mosaics, they instead extend into a set of scattered spin-offs. The key factors producing such outcomes, these cases show, are the form of partnership established at the outset of techno-experiments, and the ability of research funding and governmental agencies to steer projects as they develop
A cryogenic waveplate rotator for polarimetry at mm and sub-mm wavelengths
Mm and sub-mm waves polarimetry is the new frontier of research in Cosmic
Microwave Background and Interstellar Dust studies. Polarimeters working in the
IR to MM range need to be operated at cryogenic temperatures, to limit the
systematic effects related to the emission of the polarization analyzer. In
this paper we study the effect of the temperature of the different components
of a waveplate polarimeter, and describe a system able to rotate, in a
completely automated way, a birefringent crystal at 4K. We simulate the main
systematic effects related to the temperature and non-ideality of the optical
components in a Stokes polarimeter. To limit these effects, a cryogenic
implementation of the polarimeter is mandatory. In our system, the rotation
produced by a step motor, running at room temperature, is transmitted down to
cryogenic temperatures by means of a long shaft and gears running on custom
cryogenic bearings. Our system is able to rotate, in a completely automated
way, a birefringent crystal at 4K, dissipating only a few mW in the cold
environment. A readout system based on optical fibers allows to control the
rotation of the crystal to better than 0.1{\deg}. This device fulfills the
stringent requirements for operation in cryogenic space experiments, like the
forthcoming PILOT, BOOMERanG and LSPE.Comment: Submitted to Astronomy and Astrophysics. v1: 10 pages, 8 figures. v2:
corrected labels for the bibliographic references (no changes in the
bibliography). v3: revised version. 9 pages, 7 figures. Added a new figure.
Updated with a more realistic simulation for the interstellar dust and with
the latest cryogenic test
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