Holographic \Lambda(t)CDM model in a non-flat universe

The holographic $\Lambda(t)$CDM model in a non-flat universe is studied in this paper. In this model, to keep the form of the stress-energy of the vacuum required by general covariance, the holographic vacuum is enforced to exchange energy with dark matter. It is demonstrated that for the holographic model the best choice for the IR cutoff of the effective quantum field theory is the event horizon size of the universe. We derive the evolution equations of the holographic $\Lambda(t)$CDM model in a non-flat universe. We constrain the model by using the current observational data, including the 557 Union2 type Ia supernovae data, the cosmic microwave background anisotropy data from the 7-yr WMAP, and the baryon acoustic oscillation data from the SDSS. Our fit results show that the holographic $\Lambda(t)$CDM model tends to favor a spatially closed universe (the best-fit value of $\Omega_{k0}$ is -0.042), and the 95% confidence level range for the spatial curvature is $-0.101<\Omega_{k0}<0.040$. We show that the interaction between the holographic vacuum and dark matter induces an energy flow of which the direction is first from vacuum to dark matter and then from dark matter to vacuum. Thus, the holographic $\Lambda(t)$CDM model is just a time-varying vacuum energy scenario in which the interaction between vacuum and dark matter changes sign during the expansion of the universe.Comment: 8 pages, 4 figures. version for publication in EPJC. arXiv admin note: text overlap with arXiv:1112.235

Effects of channel noise on firing coherence of small-world Hodgkin-Huxley neuronal networks

We investigate the effects of channel noise on firing coherence of Watts-Strogatz small-world networks consisting of biophysically realistic HH neurons having a fraction of blocked voltage-gated sodium and potassium ion channels embedded in their neuronal membranes. The intensity of channel noise is determined by the number of non-blocked ion channels, which depends on the fraction of working ion channels and the membrane patch size with the assumption of homogeneous ion channel density. We find that firing coherence of the neuronal network can be either enhanced or reduced depending on the source of channel noise. As shown in this paper, sodium channel noise reduces firing coherence of neuronal networks; in contrast, potassium channel noise enhances it. Furthermore, compared with potassium channel noise, sodium channel noise plays a dominant role in affecting firing coherence of the neuronal network. Moreover, we declare that the observed phenomena are independent of the rewiring probability. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2011

A population-based study of severity of comorbidity among patients with non-Hodgkin's lymphoma: prognostic impact independent of International Prognostic Index.

Item does not contain fulltextOver 60% of patients aged over 70 years, diagnosed with non-Hodgkin's lymphoma (NHL) in the Netherlands have serious comorbidity. We studied the independent influence of comorbidity on choice of treatment, dose reductions, treatment-related toxicity and prognosis, using data from a random sample of 381 patients from the population-based Eindhoven Cancer Registry. About 45% of patients over 60 years of age with NHL had high impact comorbidity at the time of cancer diagnosis. The proportion of patients with aggressive NHL who received chemotherapy decreased from 85% in patients aged 40-60 years to 70% in those over 60 years. About 65% of systematically treated patients with aggressive NHL suffered from treatment-related toxicity. Toxicity appeared to be more common among females and those with high-intermediate or high International Prognostic Index (IPI) risk. Among patients with aggressive NHL, the chance of dying for those with high impact comorbidity was twice as high compared with those without comorbidity. This was independent of the IPI risk. Dose reductions are frequently unavoidable for patients with severe comorbidity, poor performance status or chemotherapy-related toxicity. Whether the less frequent prescription of (full dose) chemotherapy for patients with advanced age and/or with comorbidity is justified remains a question for debate

Intervention to reduce sedentary behaviour and improve outcomes after stroke (Get Set Go): a study protocol for the process evaluation of a pilot cluster randomised controlled trial (RECREATE)

Introduction Stroke survivors spend long periods of time engaging in sedentary behaviour (SB) even when their functional recovery is good. In the RECREATE programme, an intervention aimed at reducing SB (‘Get Set Go’) will be implemented and evaluated in a pragmatic external pilot cluster randomised controlled trial with embedded process and economic evaluations. We report the protocol for the process evaluation which will address the following objectives: (1) describe and clarify causal assumptions about the intervention, and its mechanisms of impact; (2) assess implementation fidelity; (3) explore views, perceptions and acceptability of the intervention to staff, stroke survivors and their carers; (4) establish the contextual factors that influence implementation, intervention mechanisms and outcomes. Methods and analysis This pilot trial will be conducted in 15 UK-based National Health Service stroke services. This process evaluation study, underpinned by the Medical Research Council guidance, will be undertaken in six of the randomised services (four intervention, two control). Data collection includes the following: observations of staff training sessions, non-participant observations in inpatient and community settings, semi-structured interviews with staff, patients and carers, and documentary analysis of key intervention components. Additional quantitative implementation data will be collected in all sites. Training observations and documentary analysis data will be summarised, with other observational and interview data analysed using thematic analysis. Relevant theories will be used to interpret the findings, including the theoretical domains framework, normalisation process theory and the theoretical framework of acceptability. Anticipated outputs include the following: recommendations for intervention refinements (both content and implementation); a revised implementation plan and a refined logic model. Ethics and dissemination The study was approved by Yorkshire & The Humber - Bradford Leeds Research Ethics Committee (REC reference: 19/YH/0403). Findings will be disseminated via peer review publications, and national and international conference presentations. Trial registration number ISRCTN82280581

Regional Process Redesign of Lung Cancer Care: A Learning Health System Pilot Project

Background: The Ottawa Hospital (TOH) defined delay to timely lung cancer care as a system design problem. Recognizing the patient need for an integrated journey and the need for dynamic alignment of providers, TOH used a learning health system (LHS) vision to redesign regional diagnostic processes. A LHS is driven by feedback utilizing operational and clinical information to drive system optimization and innovation. An essential component of a LHS is a collaborative platform that provides connectivity across silos, organizations, and professions. Methods: To operationalize a LHS, we developed the Ottawa Health Transformation Model (OHTM) as a consensus approach that addresses process barriers, resistance to change, and conflicting priorities. A regional Community of Practice (COP) was established to engage stakeholders, and a dedicated transformation team supported process improvements and implementation. Results: The project operationalized the lung cancer diagnostic pathway and optimized patient flow from referral to initiation of treatment. Twelve major processes in referral, review, diagnostics, assessment, triage, and consult were redesigned. The Ottawa Hospital now provides a diagnosis to 80% of referrals within the provincial target of 28 days. The median patient journey from referral to initial treatment decreased by 48% from 92 to 47 days. Conclusions: The initiative optimized regional integration from referral to initial treatment. Use of a LHS lens enabled the creation of a system that is standardized to best practice and open to ongoing innovation. Continued transformation initiatives across the continuum of care are needed to incorporate best practice and optimize delivery systems for regional populations