"Microscopic" approach to the Ricci dark energy

A derivation of the Ricci dark energy from quantum field theory of fluctuating "matter" fields in a classical gravitational background is presented. The coupling to the dark energy, the parameter 'a', is estimated in the framework of our formalism, and qualitatively it appears to be within observational expectations.Comment: 7 page

On the State Complexity of Partial Derivative Automata For Regular Expressions with Intersection

Extended regular expressions (with complement and intersection) are used in many applications due to their succinctness. In particular, regular expressions extended with intersection only (also called semi-extended) can already be exponentially smaller than standard regular expressions or equivalent nondeterministic finite automata (NFA). For practical purposes it is important to study the average behaviour of conversions between these models. In this paper, we focus on the conversion of regular expressions with intersection to nondeterministic finite automata, using partial derivatives and the notion of support. First, we give a tight upper bound of 2O(n) for the worst-case number of states of the resulting partial derivative automaton, where n is the size of the expression. Using the framework of analytic combinatorics, we then establish an upper bound of (1.056 + o(1))n for its asymptotic average-state complexity, which is significantly smaller than the one for the worst case. (c) IFIP International Federation for Information Processing 2016

SCORE performance in Central and Eastern Europe and former Soviet Union: MONICA and HAPIEE results

Aims: The Systematic COronary Risk Evaluation (SCORE) scale assesses 10 year risk of fatal atherosclerotic cardiovascular disease (CVD), based on conventional risk factors. The high-risk SCORE version is recommended for Central and Eastern Europe and former Soviet Union (CEE/FSU), but its performance has never been systematically assessed in the region. We evaluated SCORE performance in two sets of population-based CEE/FSU cohorts. Methods and results: The cohorts based on the World Health Organization MONitoring of trends and determinants in CArdiovascular disease (MONICA) surveys in the Czech Republic, Poland (Warsaw and Tarnobrzeg), Lithuania (Kaunas), and Russia (Novosibirsk) were followed from the mid-1980s. The Health, Alcohol, and Psychosocial factors in Eastern Europe (HAPIEE) study follows Czech, Polish (Krakow), and Russian (Novosibirsk) cohorts from 2002–05. In Cox regression analyses, the high-risk SCORE ≥5% at baseline significantly predicted CVD mortality in both MONICA [n = 15 027; hazard ratios (HR), 1.7–6.3] and HAPIEE (n = 20 517; HR, 2.6–10.5) samples. While SCORE calibration was good in most MONICA samples (predicted and observed mortality were close), the risk was underestimated in Russia. In HAPIEE, the high-risk SCORE overpredicted the estimated 10 year mortality for Czech and Polish samples and adequately predicted it for Russia. SCORE discrimination was satisfactory in both MONICA and HAPIEE. Conclusion: The high-risk SCORE underestimated the fatal CVD risk in Russian MONICA but performed well in most MONICA samples and Russian HAPIEE. This SCORE version might overestimate the risk in contemporary Czech and Polish populations

β\beta Decay and Isomeric Properties of Neutron-Rich Ca and Sc Isotopes

The isomeric and $\beta$-decay properties of neutron-rich $^{53-57}$Sc and $^{53,54}$Ca nuclei near neutron number $N$=32 are reported, and the low-energy level schemes of $^{53,54,56}$Sc and $^{53-57}$Ti are presented. The low-energy level structures of the $_{21}$Sc isotopes are discussed in terms of the coupling of the valence $1f_{7/2}$ proton to states in the corresponding $_{20}$Ca cores. Implications with respect to the robustness of the $N$=32 subshell closure are discussed, as well as the repercussions for a possible $N$=34 subshell closure.Comment: 17 pages, 17 figures, accepted to Phys. Rev.

Cross-shell excitation in two-proton knockout: Structure of 52^{52}Ca

The two-proton knockout reaction $^9$Be($^{54}$Ti,$^{52}$Ca$+ \gamma$) has been studied at 72 MeV/nucleon. Besides the strong feeding of the $^{52}$Ca ground state, the only other sizeable cross section proceeds to a 3$^-$ level at 3.9 MeV. There is no measurable direct yield to the first excited 2$^+$ state at 2.6 MeV. The results illustrate the potential of such direct reactions for exploring cross-shell proton excitations in neutron-rich nuclei and confirms the doubly-magic nature of $^{52}$Ca

Non Abelian TQFT and scattering of self dual field configuration

A non-abelian topological quantum field theory describing the scattering of self-dual field configurations over topologically non-trivial Riemann surfaces, arising from the reduction of 4-dim self-dual Yang-Mills fields, is introduced. It is shown that the phase space of the theory can be exactly quantized in terms of the space of holomorphic structures over stable vector bundles of degree zero over Riemann surfaces. The Dirac monopoles are particular static solutions of the field equations. Its relation to topological gravity is discussed.Comment: 13 pages, Late

How magic is the magic 68Ni nucleus?

We calculate the B(E2) strength in 68Ni and other nickel isotopes using several theoretical approaches. We find that in 68Ni the gamma transition to the first 2+ state exhausts only a fraction of the total B(E2) strength, which is mainly collected in excited states around 5 MeV. This effect is sensitive to the energy splitting between the fp shell and the g_{9/2}orbital. We argue that the small experimental B(E2) value is not strong evidence for the double-magic character of 68Ni.Comment: 4 pages, 4 figure

Completeness and Incompleteness of Synchronous Kleene Algebra

Synchronous Kleene algebra (SKA), an extension of Kleene algebra (KA), was proposed by Prisacariu as a tool for reasoning about programs that may execute synchronously, i.e., in lock-step. We provide a countermodel witnessing that the axioms of SKA are incomplete w.r.t. its language semantics, by exploiting a lack of interaction between the synchronous product operator and the Kleene star. We then propose an alternative set of axioms for SKA, based on Salomaa's axiomatisation of regular languages, and show that these provide a sound and complete characterisation w.r.t. the original language semantics.Comment: Accepted at MPC 201