Euclidean Path Integral and Higher-Derivative Theories

We consider the Euclidean path integral approach to higher-derivative theories proposed by Hawking and Hertog (Phys. Rev. D65 (2002), 103515). The Pais-Uhlenbeck oscillator is studied in some detail. The operator algebra is reconstructed and the structure of the space of states revealed. It is shown that the quantum theory results from quantizing the classical complex dynamics in which the original dynamics is consistently immersed. The field-theoretical counterpart of Pais-Uhlenbeck oscillator is also considered.Comment: 14 pages; no figures;the paper considerably extended; field-theoretical part adde

Selected Issues of QoS Provision in Heterogenous Military Networks

Tactical ad-hoc networks are evolving today towards complex heterogeneous networks in terms of architecture, protocols and security. Due to the difference in network resources and reliability, end-to-end quality of service provisioning becomes very challenging. If we also take into account communication issues such as unpredictable connectivity, preferential forwarding for special traffic classes, intermittency due to node or communication link failure, the problem is further aggravated.In this article, we examine the major challenges that must be solved in order to provide efficient QoS provisioning in the heterogeneous network. Finally we describe QoS-aware mechanisms for inter-domain and intra-domain heterogeneous networks, also including real-time services provision in highly mobile environments.

Out-of-hospital cardiac arrest treated by emergency medical service teams during COVID-19 pandemic: A retrospective cohort study

Background: Out-of-hospital cardiac arrest (OHCA) is a challenge for medical personnel, especiallyin the current COVID-19 pandemic, where medical personnel should perform resuscitation wearing fullpersonal protective equipment. This study aims were to assess the characteristics and outcomes of adultswho suffered an OHCA in the COVID-19 pandemic treated by emergency medical service (EMS) teams.Methods: All EMS-attended OHCA adults over than 18 years in the Polish EMS registry were analyzed.The retrospective EMS database was conducted. EMS interventions performed between March 1,and April 30, 2020 were retrospectively screened.Results: In the study period EMS operated 527 times for OHCA cases. The average age of patientswith OHCA was 67.8 years. Statistically significantly more frequently men were involved (64.3%).298 (56.6%) of all OHCA patients had resuscitation attempted by EMS providers. Among resuscitatedpatients, 73.8% were cardiac etiology. 9.4% of patients had return of spontaneous circulation, 27.2% ofpatients were admitted to hospital with ongoing chest compression. In the case of 63.4% cardiopulmonaryresuscitation was ineffective and death was determined.Conclusions: The present study found that OHCA incidence rate in the Masovian population (centralregion of Poland) in March–April 2020 period was 12.2/100,000 adult inhabitants. Return of spontaneouscirculation in EMS was observed only in 9.4% of resuscitated patients. The presence of shockablerhythms was associated with better prognosis. The prehospital mortality, even though it was high, didnot differ from those reported by other studies