885 research outputs found
Criticality and extended phase space thermodynamics of AdS black holes in higher curvature massive gravity
Considering de Rham-Gabadadze-Tolley theory of massive gravity coupled with
(ghost free) higher curvature terms arisen from the Lovelock Lagrangian, we
obtain charged AdS black hole solutions in diverse dimensions. We compute
thermodynamic quantities in the extended phase space by considering the
variations of the negative cosmological constant, Lovelock coefficients
() and massive couplings (), and prove that such variations
is necessary for satisfying the extended first law of thermodynamics as well as
associated Smarr formula. In addition, by performing a comprehensive thermal
stability analysis for the topological black hole solutions, we show in what
regions thermally stable phases exist. Calculations show the results are
radically different from those in Einstein gravity. Furthermore, we investigate
criticality of massive charged AdS black holes in higher dimensions,
including the effect of higher curvature terms and massive parameter, and find
that the critical behavior and phase transition can happen for non-compact
black holes as well as spherically symmetric ones. The phase structure and
critical behavior of topological AdS black holes are drastically restricted by
the geometry of event horizon. In this regard, the universal ratio, i.e.
, is a function of the event horizon topology. It
is shown the phase structure of AdS black holes with non-compact (hyperbolic)
horizon could give birth to three critical points corresponds to a reverse van
der Waals behavior for phase transition which is accompanied with two distinct
van der Waals phase transitions. For black holes with spherical horizon, the
van der Waals, reentrant and analogue of solid/liquid/gas phase transitions are
observed.Comment: 36 pages, 22 Figure
Changing QRS Morphology: What is the mechanism?
ECG in sinus rhythm with ventricular preexcitation and changing QRS morphology was seen that was initially interpreted as the multiple accessory pathway from elsewhere. (Figure 1A).
The following mechanisms are potentially involved in the electrogenesis of changing QRS morphology in WPW syndrome: 1) multiple accessory pathways1; 2) simultaneous occurrence of aberrant atrioventricular conduction with accessory pathway conduction 2; 3) ventricular fusion of preexcited sinus impulse with ectopic impulse.
Electrophysiologic study showed short PR (75 ms) interval with wide QRS (152 ms) and negative HV (-12 ms) interval. No change in delta wave polarity was observed during HRA and CS pacing. In full preexcitation, no breakthrough was seen in the CS. During incremental ventricular pacing, atrial breakthrough site is initially recorded on the HRA catheter and then changed to distal pole of CS catheter with progressive decrease in pacing cycle length. During ventricular pacing at cycle length of 500 ms (S1), earliest atrial activity is recorded on HRA catheter.
Changing QRS could not be explained by presence of multiple APs because only right-sided AP had bidirectional conduction and no distal CS breakthrough was seen simultaneous with changing QRS morphology. The possibility of aberrant conduction is excluded by presence of negative HV interval in the beats with differing QRS morphology. No sinus cycle length variation before and after the beats with different morphologies are against the occurrence of functional LBBB. The prematurity of ventricular electrogram in His recording catheter with variable HV (H-electrogram is recorded after V-electrogram in second beat and before V-electrogram in third beat) and fixed V-RB intervals (interval from ventricular electrogram in His to the RB potential) are compatible with ventricular fusion of preexcited sinus impulse with ectopic ventricular impulse originating from parahissian area (explaining LBBB and inferior axis morphology of the beats with changing QRS) but not from the His bundle or RBB itself (because H-electrogram and RB potential is recorded after V-electrogram in the second beat with greater degree of ventricular fusion)(Figure 1B)
Investigation the effect of ICT and innovation on the total factor productivity in Iran’s industry sector
The main purpose of this paper is to study the effect of TCT and innovation on total factor productivity () in Iranian industries from 1996-2014 by using panel data method. Amongst influential factors on productivity increase are ICT, innovation, and spillovers. Implementation of ICT like implementation of new technologies effects all sectors of economy. ICT is not only used as technology of production like traditional forms of capital but it course on increase in productivity and economic growth by substitution with other inputs. The statistical population of this survey is Iranian industries and the size of sample is 140 industries. The result of estimation indicates a positive effect from ICT on TFP. In this model the coefficient of ICT equal 0.02 which shows that a unit of increase in ICT, lead to 0.02 percent increase in TFP. Also we find that the coefficient of innovation (INNO), equal 0.04 which shows that a unit of increase in firm’s innovation, lead to 0.04 percent increase in TFP. Moreover the coefficients of LAB and INV are 0.01 and 0.003 respectively, which shows that a unit of increase in LAB and INV, leads to 0.01 and 0.003 percent increase in TFP. Keywords: Information and communication technology (ICT), Innovation, Total Factor Productivity, Panel data
Absence of isolated critical points with nonstandard critical exponents in the four-dimensional regularization of Lovelock gravity
Hyperbolic vacuum black holes in Lovelock gravity theories of odd order
are known to have the so-called isolated critical points with nonstandard
critical exponents (as , , , and ), different from those of mean-field critical exponents (with ,
, , and ). Motivated by this important
observation, here, we explore the consequences of taking the limit of
Lovelock gravity and the possibility of finding nonstandard critical exponents
associated with isolated critical points in four-dimensions by use of the
four-dimensional regularization, recently proposed by Glavan and Lin
\cite{Glavan2020}. It is shown that the regularized Einstein-Lovelock
gravity theories of odd order do not possess any physical isolated
critical point. In fact, the critical (inflection) points of equation of state
always occurs for the branch of black holes with negative entropy. The
situation is quite different for the case of the regularized
Einstein-Lovelock gravity with cubic curvature corrections (). In this
case (), although the entropy is non-negative and the equation of state of
hyperbolic vacuum black holes has a nonstandard Taylor expansion about its
inflection point, but there is no criticality associated with this special
point. At this point, the physical properties of the black hole system change
drastically, e.g., both the mass and entropy of the black hole vanishes,
meaning that there do not exist degrees of freedom in order for a phase
transition to occur. These results are in strong contrast to those findings in
Lovelock gravity.Comment: 8 pages, 4 figures, 1 tabl
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