3,172 research outputs found
Quantum Fusion of Domain Walls with Fluxes
We study how fluxes on the domain wall world volume modify quantum fusion of
two distant parallel domain walls into a composite wall. The elementary wall
fluxes can be separated into parallel and antiparallel components. The parallel
component affects neither the binding energy nor the process of quantum merger.
The antiparallel fluxes, instead, increase the binding energy and, against
naive expectations, suppress quantum fusion. In the small flux limit we
explicitly find the bounce solution and the fusion rate as a function of the
flux. We argue that at large (antiparallel) fluxes there exists a critical
value of the flux (versus the difference in the wall tensions), which switches
off quantum fusion altogether. This phenomenon of flux-related wall
stabilization is rather peculiar: it is unrelated to any conserved quantity.
Our consideration of the flux-related all stabilization is based on
substantiated arguments that fall short of complete proof.Comment: 17 pages, 3 figure
The Skyrmion strikes back: baryons and a new large limit
In the large limit of QCD, baryons can be modeled as solitons, for
instance, as Skyrmions. This modeling has been justified by Witten's
demonstration that all properties of baryons and mesons scale with
in the same way as the analogous meson-based soliton model scales with a
generic meson-meson coupling constant . An alternative large limit
(the orientifold large limit) has recently been proposed in which quarks
transform in the two-index antisymmetric representation of . By
carrying out the analog of Witten's analysis for the new orientifold large
limit, we show that baryons and solitons can also be identified in the
orientifold large limit. However, in the orientifold large limit,
the interaction amplitudes and matrix elements scale with in the
same way as soliton models scale with the generic meson coupling constant
rather than as as in the traditional large limit.Comment: 10 pages, 26 figure
Strings Inside Walls in N=1 Super Yang-Mills
We conjecture the existence of strings bounded inside walls in SU
Super Yang-Mills theory. These strings carry quantum number, where
is the greatest common divisor between , the charge of the wall, and
. We provide field-theoretical arguments and string-theoretical evidences,
both from MQCD and from gauge-gravity correspondence. We interpret this result
from the point of view of the low-energy effective action living on the
-wall.Comment: 25 pp. Major changes. In particular, following the recent work
arXiv:0807.1908 we have been able to give a field theoretical proof of the
statement. We have also corrected an important erroneous interpretation in
the previous version regarding the 2+1 effective action; Typo
Biological monitoring of workers exposed to carcinogens using the buccal or nasal micronucleus approach
Weak refinement in Z
An important aspect in the specification of distributed systems is the role of the internal (or unobservable) operation. Such operations are not part of the user interface (i.e. the user cannot invoke them), however, they are essential to our understanding and correct modelling of the system. Various conventions have been employed to model internal operations when specifying distributed systems in Z. If internal operations are distinguished in the specification notation, then refinement needs to deal with internal operations in appropriate ways. However, in the presence of internal operations, standard Z refinement leads to undesirable implementations.
In this paper we present a generalization of Z refinement, called weak refinement, which treats internal operations differently from observable operations when refining a system. We illustrate some of the properties of weak refinement through a specification of a telecommunications protocol
Vortex zero modes, large flux limit and ambjørn-nielsen-olesen magnetic instabilities
In the large flux limit vortices become flux tubes with almost constant magnetic field in the interior region. This occurs in the case of non-Abelian vortices as well, and the study of such configurations allows us to reveal a close relationship between vortex zero modes and the gyromagnetic instabilities of vector bosons in a strong background magnetic field discovered by Nielsen, Olesen and Ambj{\o}rn. The BPS vortices are exactly at the onset of this instability, and the dimension of their moduli space is precisely reproduced in this way. We present a unifying picture in which, through the study of the linear spectrum of scalars, fermions and W bosons in the magnetic field background, the expected number of translational, orientational, fermionic as well as semilocal zero modes is correctly reproduced in all cases
Digital Transformation in the Construction Sector: From BIM to Digital Twin
In the next years, perhaps more than ever before, a technological revolution will transform the construction sector in all its aspects, greatly affecting services, production, and supplies. With BIM, and even more considering the Digital Twin topic, the innovation of tools has entailed a methodological innovation for the whole sector, owing to virtual reality simulations and actual dynamic real-time monitoring. This research, starting from an integrated analysis between the current research trends and some relevant national and European projects about the digitalization of construction sector, aims at providing a systematic analysis of some of the pillars that are guiding this phenomenon. In detail, the state of the art, activities, and trends of standardization and platform development in construction sector are considered and intersected to provide a clear background towards the future trends in the sector
Post-translational aging of proteins in osteoarthritic cartilage and synovial fluid as measured by isomerized aspartate
INTRODUCTION: Aging proteins undergo non-enzymatic post-translational modification, including isomerization and racemization. We hypothesized that cartilage with many long-lived components could accumulate non-enzymatically modified amino acids in the form of isomerized aspartate and that its liberation due to osteoarthritis (OA)-related cartilage degradation could reflect OA severity. METHODS: Articular cartilage and synovial fluid were obtained from 14 randomly selected total knee arthroplasty cases (56 to 79 years old) and non-arthritis cartilage from 8 trauma cases (51 to 83 years old). Paired lesional cartilage and non-lesioned OA cartilage were graded histologically using a modified Mankin system. Paired cartilage and synovial fluids were assayed for isomerized aspartate, phosphate-buffered saline/EDTA (ethylenediaminetetraacetic acid) extractable glycosaminoglycans, and total protein. Macroscopically normal non-lesioned OA cartilage was separated into superficial and deep regions when cartilage thickness was at least 3 mm (n = 6). RESULTS: Normalized to cartilage wet weight, normal cartilage and deep non-lesioned OA cartilage contained significantly (P < 0.05) more isomerized aspartate than superficial non-lesioned OA cartilage and lesioned cartilage. Synovial fluid isomerized aspartate correlated positively (R2 = 0.53, P = 0.02) and glycosaminoglycans correlated negatively (R2 = 0.42, P = 0.04) with histological OA lesion severity. Neither synovial fluid isomerized aspartate nor glycosaminoglycans nor total protein correlated with histological scores of non-lesioned areas. CONCLUSIONS: We show for the first time that human cartilage and synovial fluid contain measurable quantities of an isomerized amino acid and that synovial fluid concentrations of isomerized aspartate reflected severity of histological OA. Further assessment is warranted to identify the cartilage proteins containing this modification and to assess the functional consequences and biomarker applications of this analyte in OA
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