312 research outputs found
Primary Molar Pulpotomies with Different Hemorrhage Control Agents and Base Materials: A Randomized Clinical Trial
Objective: To evaluate the clinical and radiographical success of primary molar pulpotomies which used 15.5% ferric sulfate (FS) or 1.25% sodium hypochlorite (NaOCl) for hemostasis and zinc oxide-eugenol (ZOE) and calcium hydroxide (CH) pastes as base materials.
Methods: In 29 healthy children, 80 primary molars were randomly allocated to one of the study groups: Group 1: FS-ZOE, Group 2: FS-CH, Group 3: NaOCl-ZOE, and Group 4: NaOCl-CH. After hemostasis with the respective solutions, pulp stumps and floor of the pulp chambers were covered with either ZOE or CH pastes. All teeth were restored with stainless steel crowns. Follow-up examinations were carried out at 1, 3, 6, and 12 months.
Results: One tooth in Group 1 and two teeth in Group 4 were extracted because of pain and periapial pathosis at sixth month. After 12 months, clinical success rates of pulpotomies in Groups 1-4 were 95%, 100%, 100%, and 89.5%, respectively. The differences were not significant (P = 0.548). Radiographic success rates for Groups 1-4 were 80%, 88.9%, 78.9%, and 84.2%, respectively. No statistically significant difference was found (P = 0.968). Pain on percussion was the most observed clinical finding. However, internal root resorption was the most common radiological finding and it was observed significantly more in mandibular primary molars (P \u3c 0.05).
Conclusion: Both ZOE and CH can be preferred as base materials after hemostasis achieved by the use of 15.5% FS or 1.25% NaOCl in primary tooth pulpotomy
On the BPS Spectrum at the Root of the Higgs Branch
We study the BPS spectrum and walls of marginal stability of the
supersymmetric theory in four dimensions with gauge group SU(n)
and fundamental flavours at the root of the Higgs branch. The
strong-coupling spectrum of this theory was conjectured in hep-th/9902134 to
coincide with that of the two-dimensional supersymmetric
sigma model. Using the Kontsevich--Soibelman
wall-crossing formula, we start with the conjectured strong-coupling spectrum
and extrapolate it to all other regions of the moduli space. In the
weak-coupling regime, our results precisely agree with the semiclassical
analysis of hep-th/9902134: in addition to the usual dyons, quarks, and
bosons, if the complex masses obey a particular inequality, the resulting
weak-coupling spectrum includes a tower of bound states consisting of a dyon
and one or more quarks. In the special case of -symmetric
masses, there are bound states with one quark for odd and no bound states
for even .Comment: 11 pages, 4 figure
The General Supersymmetric Solution of Topologically Massive Supergravity
We find the general fully non-linear solution of topologically massive
supergravity admitting a Killing spinor. It is of plane-wave type, with a null
Killing vector field. Conversely, we show that all solutions with a null
Killing vector are supersymmetric for one or the other choice of sign for the
Chern-Simons coupling constant \mu. If \mu does not take the critical value
\mu=\pm 1, these solutions are asymptotically regular on a Poincar\'e patch,
but do not admit a smooth global compactification with boundary S^1\times\R. In
the critical case, the solutions have a logarithmic singularity on the boundary
of the Poincar\'e patch. We derive a Nester-Witten identity, which allows us to
identify the associated charges, but we conclude that the presence of the
Chern-Simons term prevents us from making a statement about their positivity.
The Nester-Witten procedure is applied to the BTZ black hole.Comment: Minor correction
Bending AdS Waves with New Massive Gravity
We study AdS-waves in the three-dimensional new theory of massive gravity
recently proposed by Bergshoeff, Hohm, and Townsend. The general configuration
of this type is derived and shown to exhibit different branches, with different
asymptotic behaviors. In particular, for the special fine tuning
, solutions with logarithmic fall-off arise, while in the
range , spacetimes with Schrodinger isometry group are admitted
as solutions. Solutions that are asymptotically AdS, both for
Brown-Henneaux and for the weakened boundary conditions, are also identified.
The metric function that characterizes the profile of the AdS-wave behaves as a
massive excitation on the spacetime, with an effective mass given by
. For the critical value , the value of
the effective mass precisely saturates the Breitenlohner-Freedman bound for the
AdS space where the wave is propagating on. The analogies with the AdS-wave
solutions of topologically massive gravity are also discussed. Besides, we
consider the coupling of both massive deformations to Einstein gravity and find
the exact configurations for the complete theory, discussing all the different
branches exhaustively. One of the effects of introducing the Chern-Simons
gravitational term is that of breaking the degeneracy in the effective mass of
the generic modes of pure New Massive Gravity, producing a fine structure due
to parity violation. Another effect is that the zoo of exact logarithmic
specimens becomes considerably enlarged.Comment: 9 pages. Minor typos correcte
A Study of Wall-Crossing: Flavored Kinks in D=2 QED
We study spectrum of D=2 N=(2,2) QED with N+1 massive charged chiral
multiplets, with care given to precise supermultiplet countings. In the
infrared the theory flows to CP^N model with twisted masses, where we construct
generic flavored kink solitons for the large mass regime, and study their
quantum degeneracies. These kinks are qualitatively different and far more
numerous than those of small mass regime, with features reminiscent of
multi-pronged (p,q) string web, complete with the wall-crossing behavior. It
has been also conjectured that spectrum of this theory is equivalent to the
hypermultiplet spectrum of a certain D=4 Seiberg-Witten theory. We find that
the correspondence actually extends beyond hypermultiplets in D=4, and that
many of the relevant indices match. However, a D=2 BPS state is typically
mapped to several different kind of dyons whose individual supermultiplets are
rather complicated; the match of index comes about only after summing over
indices of these different dyons. We note general wall-crossing behavior of
flavored BPS kink states, and compare it to those of D=4 dyons.Comment: 47 pages, 5 figures; typos fixed; references adde
Three-dimensional black holes, gravitational solitons, kinks and wormholes for BHT massive gravity
The theory of massive gravity in three dimensions recently proposed by
Bergshoeff, Hohm and Townsend (BHT) is considered. At the special case when the
theory admits a unique maximally symmetric solution, a conformally flat space
that contains black holes and gravitational solitons for any value of the
cosmological constant is found. For negative cosmological constant, the black
hole is characterized in terms of the mass and the "gravitational hair"
parameter, providing a lower bound for the mass. For negative mass parameter,
the black hole acquires an inner horizon, and the entropy vanishes at the
extremal case. Gravitational solitons and kinks, being regular everywhere, are
obtained from a double Wick rotation of the black hole. A wormhole solution in
vacuum that interpolates between two static universes of negative spatial
curvature is obtained as a limiting case of the gravitational soliton with a
suitable identification. The black hole and the gravitational soliton fit
within a set of relaxed asymptotically AdS conditions as compared with the ones
of Brown and Henneaux. In the case of positive cosmological constant the black
hole possesses an event and a cosmological horizon, whose mass is bounded from
above. Remarkably, the temperatures of the event and the cosmological horizons
coincide, and at the extremal case one obtains the analogue of the Nariai
solution, . A gravitational soliton is also obtained
through a double Wick rotation of the black hole. The Euclidean continuation of
these solutions describes instantons with vanishing Euclidean action. For
vanishing cosmological constant the black hole and the gravitational soliton
are asymptotically locally flat spacetimes. The rotating solutions can be
obtained by boosting the previous ones in the plane.Comment: Talk given at the "Workshop on Gravity in Three Dimensions," 14-24
April 2009, ESI, Vienna. 30 pages, 6 figures. V2: minor changes and section 6
slightly improved. Last version for JHE
Holography for chiral scale-invariant models
Deformation of any d-dimensional conformal field theory by a constant null
source for a vector operator of dimension (d + z -1) is exactly marginal with
respect to anisotropic scale invariance, of dynamical exponent z. The
holographic duals to such deformations are AdS plane waves, with z=2 being the
Schrodinger geometry. In this paper we explore holography for such chiral
scale-invariant models. The special case of z=0 can be realized with gravity
coupled to a scalar, and is of particular interest since it is related to a
Lifshitz theory with dynamical exponent two upon dimensional reduction. We show
however that the corresponding reduction of the dual field theory is along a
null circle, and thus the Lifshitz theory arises upon discrete light cone
quantization of an anisotropic scale invariant field theory.Comment: 62 pages; v2, published version, minor improvements and references
adde
An Agent-Based Model of Heterogeneous Driver Behaviour and Its Impact on Energy Consumption and Costs in Urban Space
By 2020, over 100 countries had expanded electric and plug-in hybrid electric vehicle (EV/PHEV) technologies, with global sales surpassing 7 million units. Governments are adopting cleaner vehicle technologies due to the proven environmental and health implications of internal combustion engine vehicles (ICEVs), as evidenced by the recent COP26 meeting. This article proposes an agent-based model of vehicle activity as a tool for quantifying energy consumption by simulating a fleet of EV/PHEVs within an urban street network at various spatio-temporal resolutions. Driver behaviour plays a significant role in energy consumption; thus, simulating various levels of individual behaviour and enhancing heterogeneity should provide more accurate results of potential energy demand in cities. The study found that (1) energy consumption is lowest when speed limit adherence increases (low variance in behaviour) and is highest when acceleration/deceleration patterns vary (high variance in behaviour); (2) vehicles that travel for shorter distances while abiding by speed limit rules are more energy efficient compared to those that speed and travel for longer; and (3) on average, for tested vehicles, EV/PHEVs were ÂŁ233.13 cheaper to run than ICEVs across all experiment conditions. The difference in the average fuel costs (electricity and petrol) shrinks at the vehicle level as driver behaviour is less varied (more homogeneous). This research should allow policymakers to quantify the demand for energy and subsequent fuel costs in cities
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