Inflation in asymptotically safe f(R) theory

We discuss the existence of inflationary solutions in a class of renormalization group improved polynomial f(R) theories, which have been studied recently in the context of the asymptotic safety scenario for quantum gravity. These theories seem to possess a nontrivial ultraviolet fixed point, where the dimensionful couplings scale according to their canonical dimensionality. Assuming that the cutoff is proportional to the Hubble parameter, we obtain modified Friedmann equations which admit both power law and exponential solutions. We establish that for sufficiently high order polynomial the solutions are reliable, in the sense that considering still higher order polynomials is very unlikely to change the solution.Comment: Presented at 14th Conference on Recent Developments in Gravity: NEB 14, Ioannina, Greece, 8-11 Jun 201

Dynamical System Analysis of Cosmologies with Running Cosmological Constant from Quantum Einstein Gravity

We discuss a mechanism that induces a time-dependent vacuum energy on cosmological scales. It is based on the instability induced renormalization triggered by the low energy quantum fluctuations in a Universe with a positive cosmological constant. We employ the dynamical systems approach to study the qualitative behavior of Friedmann-Robertson-Walker cosmologies where the cosmological constant is dynamically evolving according with this nonperturbative scaling at low energies. It will be shown that it is possible to realize a "two regimes" dark energy phases, where an unstable early phase of power-law evolution of the scale factor is followed by an accelerated expansion era at late times.Comment: 26 pages, 4 figures. To appear in New Journal of Physic

Improved Action Functionals in Non-Perturbative Quantum Gravity

Models of gravity with variable G and Lambda have acquired greater relevance after the recent evidence in favour of the Einstein theory being non-perturbatively renormalizable in the Weinberg sense. The present paper builds a modified Arnowitt-Deser-Misner (ADM) action functional for such models which leads to a power-law growth of the scale factor for pure gravity and for a massless phi**4 theory in a Universe with Robertson-Walker symmetry, in agreement with the recently developed fixed-point cosmology. Interestingly, the renormalization-group flow at the fixed point is found to be compatible with a Lagrangian description of the running quantities G and Lambda.Comment: Latex file. Record without file already exists on SLAC-SPIRES, and hence that record and the one for the present arxiv submission should become one record onl

An effective action for asymptotically safe gravity

Asymptotically safe theories of gravitation have received great attention in recent times. In this framework an effective action embodying the basic features of the renormalized flow around the non-gaussian fixed point is derived and its implications for the early universe are discussed. In particular, a "landscape" of a countably infinite number of cosmological inflationary solutions characterized by an unstable de Sitter phase lasting for a large enough number of e-folds is found.Comment: 5 pages, to appear as a Rapid Communication in Physical Review

On the spectrum of the transfer operators of a one-parameter family with intermittency transition

We study the transfer operators for a family $F_r:[0,1] \to [0,1]$ depending on the parameter $r\in [0,1]$, which interpolates between the tent map and the Farey map. In particular, considering the action of the transfer operator on a suitable Hilbert space, we can define a family of infinite matrices associated to the operators and study their spectrum by numerical methods.Comment: 6 pages, 3 figure

A Class of Renormalization Group Invariant Scalar Field Cosmologies

We present a class of scalar field cosmologies with a dynamically evolving Newton parameter $G$ and cosmological term $\Lambda$. In particular, we discuss a class of solutions which are consistent with a renormalization group scaling for $G$ and $\Lambda$ near a fixed point. Moreover, we propose a modified action for gravity which includes the effective running of $G$ and $\Lambda$ near the fixed point. A proper understanding of the associated variational problem is obtained upon considering the four-dimensional gradient of the Newton parameter.Comment: 10 pages, RevTex4, no figures, to appear on GR

Nurse Anesthesia Program Administrator\u27s Decision-Making in Determining Interventions for a Student Exhibiting Unsatisfactory Clinical Performance

The purpose of this grounded theory study is to define the process that nurse anesthesia program administrators use to determine if a student nurse anesthetist’s unsatisfactory clinical performance warrants intervention by the program. There is little room for error in anesthesia practice as mishaps typically result in significant injury and death. Students who exhibit unsatisfactory clinical performance may pose an immediate risk to patient safety as well as a future risk if allowed to progress in the program. The lack of guidance in the form of clearly articulated expectations and processes contribute to the emotional strain nurse anesthesia faculty and administrators experience when observing unsatisfactory clinical performance. From the data collected in the interviews with ten nurse anesthesia program administrators, a five-phase decision-making model entitled the Nurse Anesthesia Program Administrator Decision Making Model was developed. The five phases of the model include: receiving the feedback, validating the concern, assessing accountability and planning for remediation, removing the student from clinical training and moving to dismissal, and notifying the student of the decision. The guiding principle of this model is the importance of following institutional and program policies throughout the process. This study is intended to provide guidance to nurse anesthesia program administrators who are faced with a student demonstrating unsatisfactory clinical performance regarding what behaviors may require an intervention by the program

Nurse Anesthesia Program Administrator\u27s Decision-Making in Determining Interventions for a Student Exhibiting Unsatisfactory Clinical Performance

The purpose of this grounded theory study is to define the process that nurse anesthesia program administrators use to determine if a student nurse anesthetist’s unsatisfactory clinical performance warrants intervention by the program. There is little room for error in anesthesia practice as mishaps typically result in significant injury and death. Students who exhibit unsatisfactory clinical performance may pose an immediate risk to patient safety as well as a future risk if allowed to progress in the program. The lack of guidance in the form of clearly articulated expectations and processes contribute to the emotional strain nurse anesthesia faculty and administrators experience when observing unsatisfactory clinical performance. From the data collected in the interviews with ten nurse anesthesia program administrators, a five-phase decision-making model entitled the Nurse Anesthesia Program Administrator Decision Making Model was developed. The five phases of the model include: receiving the feedback, validating the concern, assessing accountability and planning for remediation, removing the student from clinical training and moving to dismissal, and notifying the student of the decision. The guiding principle of this model is the importance of following institutional and program policies throughout the process. This study is intended to provide guidance to nurse anesthesia program administrators who are faced with a student demonstrating unsatisfactory clinical performance regarding what behaviors may require an intervention by the program

Flow Equations for U_k and Z_k

By considering the gradient expansion for the wilsonian effective action S_k of a single component scalar field theory truncated to the first two terms, the potential U_k and the kinetic term Z_k, I show that the recent claim that different expansion of the fluctuation determinant give rise to different renormalization group equations for Z_k is incorrect. The correct procedure to derive this equation is presented and the set of coupled differential equations for U_k and Z_k is definitely established.Comment: 5 page