Conditional expectations associated with quantum states

An extension of the conditional expectations (those under a given subalgebra of events and not the simple ones under a single event) from the classical to the quantum case is presented. In the classical case, the conditional expectations always exist; in the quantum case, however, they exist only if a certain weak compatibility criterion is satisfied. This compatibility criterion was introduced among others in a recent paper by the author. Then, state-independent conditional expectations and quantum Markov processes are studied. A classical Markov process is a probability measure, together with a system of random variables, satisfying the Markov property and can equivalently be described by a system of Markovian kernels (often forming a semigroup). This equivalence is partly extended to quantum probabilities. It is shown that a dynamical (semi)group can be derived from a given system of quantum observables satisfying the Markov property, and the group generators are studied. The results are presented in the framework of Jordan operator algebras, and a very general type of observables (including the usual real-valued observables or self-adjoint operators) is considered.Comment: 10 pages, the original publication is available at http://www.aip.or

Rehabilitation strategies for optimisation of functional recovery after major joint replacement

Exercise-based interventions applied before and after total hip and knee arthroplasty (THA and TKA, respectively) have been investigated for a number of years, based on the assumption that they will enhance post-operative recovery. Although recent studies suggest that high-volume, pre-operative exercise may enhance post-operative recovery after TKA, studies of post-operative exercise-based interventions, have not found superiority of one exercise regime over another. It seems, however, that post-operative, exercise-based, rehabilitation is superior to no or minimal rehabilitation after THA and TKA. The goal of this commentary is to summarize recent evidence for the efficacy of different peri-operative exercise-based interventions to enhance recovery after THA and TKA, and to propose new strategies to further enhance post-operative recovery. There is a major need to improve functional recovery after THA and TKA. We propose a strategy of “enriched” trials where specific rehabilitation interventions are applied to different patients based on, for example, their expectations for post-operative recovery, willingness to undertake exercise and physical activity, and pre-operative functional performance

Outcomes in elderly Danish citizens admitted with community-acquired pneumonia. Regional differencties, in a public healthcare system

SummaryObjectivesTo evaluate regional differences in and risk factors for admission, length of stay, mortality, and readmission for community-acquired pneumonia in elderly Danish patients.MethodsNational registry study on elderly Danish citizens with an acute admission in 2009 owing to community-acquired pneumonia. We studied differences among hospitals in length of stay, in-hospital mortality, mortality within 30 days of discharge, and readmission within 30 days after discharge using Cox regression models with adjustments for age, sex, ventilatory support, and co-morbidity by Charlson's index score.ResultsA total of 11,332 elderly citizens were admitted with community-acquired pneumonia. Mortality during admission and 30-days from discharge were 11.6% and 16.2%, respectively. Readmission rates within 30 days of discharge were 12.3%. There were significantly differences between hospitals in length of stay. A high Charlson index score and advanced age were significantly risk factors for death during admission and within 30 days of discharge. Male sex and high Charlson index score were significant risk factors for readmission. Admission to large bed capacity hospital was a significant risk factor for death and readmission within 30 days of discharge.ConclusionsLength of stay, rate of admission, mortality and readmission in elderly Danish patients with community-acquired pneumonia follows international findings. There are regional differences between hospitals. In depth investigation in regional differences could reveal potential feasible clinical interventions with an improvement of readmission-, mortality rates and cost