OzDES reverberation mapping program: lag recovery reliability for 6-yr C IV analysis

We present the statistical methods that have been developed to analyse the OzDES reverberation mapping sample. To perform this statistical analysis we have created a suite of customizable simulations that mimic the characteristics of each source in the OzDES sample. These characteristics include: the variability in the photometric and spectroscopic light curves, the measurement uncertainties, and the observational cadence. By simulating the sources in the OzDES sample that contain the C iv emission line, we developed a set of criteria that rank the reliability of a recovered time-lag depending on the agreement between different recovery methods, the magnitude of the uncertainties, and the rate at which false positives were found in the simulations. These criteria were applied to simulated light curves and these results used to estimate the quality of the resulting Radius-Luminosity relation. We grade the results using three quality levels (gold, silver, and bronze). The input slope of the R-L relation was recovered within 1σ for each of the three quality samples, with the gold standard having the lowest dispersion with a recovered a R-L relation slope of 0.454 ± 0.016 with an input slope of 0.47. Future work will apply these methods to the entire OzDES sample of 771 AGN

Large Eddy Simulation of Reacting Flows Applied to Bluff Body Stabilized Flames

The objective of this paper is to present a large eddy simulation model for chemically reacting flows. The large eddy simulation model, founded on a physical model based on modern continuum mechanics, includes a complete treatment of the subgrid stresses and fluxes including both backscatter and diffusion. To investigate the predictive capabilities of the large eddy simulation model, numerical simulations of a configuration corresponding to a rig consisting of a rectilinear channel with a triangular-shaped bluff body have been performed. Both nonreacting and reacting flows have been examined under a variety of operating conditions. This paper focuses on the reacting case, which is characterized as lean and premixed. The simulation results are compared to experimental measurements of temperature, constituent mass fraction, and velocity fields in the test rig. The results indicate that the large eddy simulation technique works well and mimics most of the significant flow features, including the typical unsteady flow structures. The results from the large eddy simulations are furthermore used to investigate the mechanisms responsible for the typical flowfield in a bluff body stabilized flame

Large eddy simulation of unsteady combustion

The present study concerns the application of a large eddy simulation (LES) model, capable of dealing with chemical reactions described by multistep reaction mechanisms and thermal radiation. The LES model, based on prefiltering of the balance equations of mass, momentum, and energy contains a variety of submodels far representing the residual stress tensor and flux vectors and the filtered reaction rates. Here, we have focused on the influence of modeling of the filtered reaction rates. Three different reaction rate formulations have been investigated, the eddy dissipation kinetic model, a model based on the presumed PDF approach, and finally a monotonically integrated LES model that does not explicitly take subgrid scale effects into account. The predictive capabilities of the LES model have been investigated by numerical simulations of the flow past a triangular-shaped flame holder in a rectilinear channel at various operating conditions parameterized by the equivalence ratio, inlet velocity, and temperature. In simulations of reacting flow situations, the fuel was propane and premixed conditions were enforced. Detailed experimental measurements of all operating conditions including temperature probability density functions are available. Comparison of simulated and measured quantities indicates that the LES model is capable of predicting the flow accurately under all three operating conditions and that the movement of the flame front can be captured. Moreover, a discussion describing the dissimilar modes of operation found in the test rig is presented

Cognitive dysfunction in post-COVID-19 condition : mechanisms, management, and rehabilitation

The long-term effects of COVID-19 on cognitive function have become an area of increasing concern. This paper provides an overview of characteristics, risk factors, possible mechanisms, and management strategies for cognitive dysfunction in post-COVID-19 condition (PCC). Prolonged cognitive dysfunction is one of the most common impairments in PCC, affecting between 17% and 28% of the individuals more than 12 weeks after the infection and persisting in some cases for several years. Cognitive dysfunctions can be manifested as a wide range of symptoms including memory impairment, attention deficit, executive dysfunction, and reduced processing speed. Risk factors for developing PCC, with or without cognitive impairments, include advanced age, preexisting medical conditions, and the severity of acute illness. The underlying mechanisms remain unclear, but proposed contributors include neuroinflammation, hypoxia, vascular damage, and latent virus reactivation not excluding the possibility of direct viral invasion of the central nervous system, illustrating complex viral pathology. As the individual variation of the cognitive impairments is large, a neuropsychological examination and a person-centered multidimensional approach are required. According to the World Health Organization, limited evidence on COVID-19-related cognitive impairments necessitates implementing rehabilitation interventions from established practices of similar conditions. Psychoeducation and compensatory skills training are recommended. Assistive products and environmental modifications adapted to individual needs might be helpful. In specific attention- and working memory dysfunctions, cognitive training—carefully monitored for intensity—might be effective for people who do not suffer from post-exertional malaise. Further research is crucial for evidence-based interventions specific to COVID-19-related cognitive impairments

Radiotherapy techniques in current use in Sweden.

A systematic assessment of radiotherapy for cancer was conducted by The Swedish Council on Technology Assessment in Health Care (SBU) in 2001. The assessment included a review of radiotherapy techniques in current use in Sweden. The following conclusions were drawn: Radiotherapy demands adequate knowledge of diagnostic methods, anatomy, cancer biology and of the physical and biological properties of ionizing radiation. Well-functioning teamwork on the part of the oncologist, medical physicist and oncology nurse is important.Radiotherapy has a high degree of technical sophistication, including the use of computers, which necessitates expert technical support.Technical development is rapid, and since the previous report, multileaf collimators and electronic portal imaging have been introduced in the clinical routine.The use of brachytherapy for treatment of non-gynaecological malignancies is rapidly increasing.The need for quality assurance in all steps of the radiotherapy procedure is stressed. A critical review of the literature on intraoperative radiotherapy is also included as an Appendix