University of Turku

About: University of Turku is a education organization based out in Turku, Finland. It is known for research contribution in the topics: Population & Galaxy. The organization has 16296 authors who have published 45124 publications receiving 1505428 citations. The organization is also known as: Turun yliopisto & Åbo universitet.

Doppler factors, Lorentz factors and viewing angles for quasars, BL Lacertae objects and radio galaxies

Abstract: Aims. We have calculated variability Doppler boosting factors, Lorentz factors, and viewing angles for a large sample of sources by using total flux density observations at 22 and 37 GHz and VLBI data. Methods. We decomposed the flux curves into exponential flares and determined the variability brightness temperatures of the fastest flares. By assuming the same intrinsic brightness temperature for each source, we calculated the Doppler boosting factors for 87 sources. In addition we used new apparent jet speed data to calculate the Lorentz factors and viewing angles for 67 sources. Results. We find that all quasars in our sample are Doppler-boosted and that the Doppler boosting factors of BL Lacertae objects are lower than of quasars. The new Lorentz factors are about twice as high as in earlier studies, which is mainly due to higher apparent speeds in our analyses. The jets of BL Lacertae objects are slower than of quasars. There are some extreme sources with very high derived Lorentz factors of the order of a hundred. These high Lorentz factors could be real. It is also possible that the sources exhibit such rapid flares that the fast variations have remained undetected in monitoring programmes, or else the sources have a complicated jet structure that is not amenable to our simple analysis. Almost all the sources are seen in a small viewing angle of less than 20 degrees. Our results follow the predictions of basic unification schemes for AGN.

Positron Emission Tomography Is Superior to Computed Tomography Scanning for Response-Assessment After Radical Radiotherapy or Chemoradiotherapy in Patients With Non–Small-Cell Lung Cancer

Abstract: Purpose: To prospectively study the capacity of positron emission tomography (PET) and computed tomography (CT) to determine response soon after radical radiotherapy or chemoradiotherapy and, thereby, predict survival. PET is known to provide a more accurate estimate of true extent of disease than CT when used to stage non–small-cell lung cancer (NSCLC). Patients and Methods: Seventy-three patients with NSCLC underwent [18F]fluorodeoxyglucose PET and CT scans before and after radical radiotherapy (n = 10) or chemoradiotherapy (n = 63). Follow-up PET scans were performed at a median of 70 days after radiotherapy. The median PET-CT interval was 1 day. Each patient had determinations of response to therapy made with PET and CT, categorized as complete response, partial response, no response, progressive disease, or nonassessable. Responses were correlated with subsequent survival. Results: Median survival after follow-up PET was 24 months. There was poor agreement between PET and CT responses (weighted kappa...

Mortality and cause of death in hip fracture patients aged 65 or older - a population-based study

Abstract: The high mortality of hip fracture patients is well documented, but sex- and cause-specific mortality after hip fracture has not been extensively studied. The purpose of the present study was to evaluate mortality and cause of death in patients after hip fracture surgery and to compare their mortality and cause of death to those in the general population. Records of 428 consecutive hip fracture patients were collected on a population-basis and data on the general population comprising all Finns 65 years of age or older were collected on a cohort-basis. Cause of death was classified as follows: malignant neoplasms, dementia, circulatory disease, respiratory disease, digestive system disease, and other. Mean follow-up was 3.7 years (range 0-9 years). Overall 1-year postoperative mortality was 27.3% and mortality after hip fracture at the end of the follow-up was 79.0%. During the follow-up, age-adjusted mortality after hip fracture surgery was higher in men than in women with hazard ratio (HR) 1.55 and 95% confidence interval (95% CI) 1.21-2.00. Among hip surgery patients, the most common causes of death were circulatory diseases, followed by dementia and Alzheimer's disease. After hip fracture, men were more likely than women to die from respiratory disease, malignant neoplasm, and circulatory disease. During the follow-up, all-cause age- and sex-standardized mortality after hip fracture was 3-fold higher than that of the general population and included every cause-of-death category. During the study period, the risk of mortality in hip fracture patients was 3-fold higher than that in the general population and included every major cause of death.