1,022,634 research outputs found
The super algebra and its associated generalized KdV hierarchies
We construct the super algebra as a certain reduction of the
second Gel'fand-Dikii bracket on the dual of the Lie superalgebra of
super pseudo-differential operators. The algebra is put in manifestly
supersymmetric form in terms of three superfields , with
being the energy momentum tensor and and being
conformal spin and superfields respectively. A search for integrable
hierarchies of the generalized KdV variety with this algebra as Hamiltonian
structure gives three solutions, exactly the same number as for the
(super KdV) and (super Boussinesq) cases.Comment: 16 pages, LaTeX, UTAS-PHYS-92-3
Cherenkov gluons at RHIC and LHC
The coherent hadron production analogous to Cherenkov radiation of photons
gives rise to the ring-like events. Being projected on the ring diameter they
produce the two-bump structure recently observed for the away-side jets at
RHIC. The position of the peaks and their height determine such properties of
the hadronic medium as its nuclear index of refraction, the parton density, the
free path length and the energy loss of Cherenkov gluons. Beside comparatively
low energy gluons observed at RHIC, there could be high energy gluons at LHC,
related to the high energy region of positive real part of the forward
scattering amplitude and possessing different characteristics.Comment: 6 pages, talk at QM2006 modified with new reference
Friedel oscillations at the surfaces of rhombohedral -layer graphene
The low-energy physics of rhombohedral -layer graphene mainly arises on
the external layers, where most of the {\pi} electrons are located. Their Bloch
band structure defines a two-band semimetal; the dispersion relation scales as
with the momentum norm in the vicinity of two nonequivalent
valleys. In this paper, we address the problem of elastic scattering through a
localized impurity located either on the surface of the material or within the
bulk, and focus on the quantum interferences it induces on the two external
layers. It is apprehended in the framework of a -matrix approach, both
numerically and analytically, regardless of the impurity magnitude, which
enables the description of realistic scatters. In rhombohedral multilayer
graphene, the impurity induces Friedel oscillations that always decay as .
As a result, monolayer graphene is the only material of the rhombohedral class
that exhibits -decaying Friedel oscillations. The interference
patterns are subsequently analyzed in momentum space. This analysis enables a
clear distinction between monolayer graphene and multilayer graphene. It also
shows that the interference pattern reveals the whole Bloch band structure, and
highlights the number of layers stacked in the material, as well as the
-quantized Berry phases that characterize the existence of nodal points
in the semimetallic spectrum. Experimentally, these features may be probed from
scanning tunneling microscopy, when imaging the local density of states at the
surfaces of suspended rhombohedral -layer graphene
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European local authorities’ financial resilience in the face of austerity: a comparison across Austria, Italy and England
European local authorities have been particularly stricken by the current context of decline and cutback management, and represent an ideal place where to study how governments respond to shocks affecting their financial conditions and management. Along these lines, this paper adopt the perspective of financial resilience for looking at the current context of austerity, and related responses, by shedding new lights on the role of internal capacities and conditions in influencing such responses and, ultimately, performance. Through a multiple case study analysis based on 12 European local authorities in Austria, Italy and England, the paper identifies the main shocks perceived by local management, the related short-term and long-term responses, highlighting the dynamics of financial vulnerabilty, awareness, anticipatory capacity, flexibility and recovery ability (ie, financial resilience) in its interaction with the external context and shocks. From the analysis, four patterns of resilience emerge: pro-active resilience, adaptive resilience, passive/fatalist resilience, complacent resilience
Visual Molecular Dynamics Investigations of the Impact of Hydrophobic Nanoparticles on Prognosis of Alzheimer’s Disease and Cancers
The possible impact of hydrophobic lectin nanoparticles on the prognosis and progression of Alzheimer's disease (AD) and cancers was investigated by Visual Molecular Dynamics (VMD) computer modeling programs available from the Beckmann Advanced Research Institute at the University of Illinois at Urbana. Our results indicate the possibility of impeding pathological aggregation of certain proteins such as modified tau- or beta-amyloid that are currently being considered as possible causes of Alzheimer's disease. VMD programs serve as useful tools for investigation hydrophobic protein aggregation that may play a role in aging of human populations
On global location-domination in graphs
A dominating set of a graph is called locating-dominating, LD-set for
short, if every vertex not in is uniquely determined by the set of
neighbors of belonging to . Locating-dominating sets of minimum
cardinality are called -codes and the cardinality of an LD-code is the
location-domination number . An LD-set of a graph is global
if it is an LD-set of both and its complement . The global
location-domination number is the minimum cardinality of a
global LD-set of . In this work, we give some relations between
locating-dominating sets and the location-domination number in a graph and its
complement.Comment: 15 pages: 2 tables; 8 figures; 20 reference
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