Regression calibration for Cox regression under heteroscedastic measurement error - Determining risk factors of cardiovascular diseases from error-prone nutritional replication data

For instance nutritional data are often subject to severe measurement error, and an adequate adjustment of the estimators is indispensable to avoid deceptive conclusions. This paper discusses and extends the method of regression calibration to correct for measurement error in Cox regression. Special attention is paid to the modelling of quadratic predictors, the role of heteroscedastic measurement error, and the efficient use of replicated measurements of the surrogates. The method is used to analyze data from the German part of the MONICA cohort study on cardiovascular diseases. The results corroborate the importance of taking into account measurement error carefully

Classical and all-floating FETI methods for the simulation of arterial tissues

High-resolution and anatomically realistic computer models of biological soft tissues play a significant role in the understanding of the function of cardiovascular components in health and disease. However, the computational effort to handle fine grids to resolve the geometries as well as sophisticated tissue models is very challenging. One possibility to derive a strongly scalable parallel solution algorithm is to consider finite element tearing and interconnecting (FETI) methods. In this study we propose and investigate the application of FETI methods to simulate the elastic behavior of biological soft tissues. As one particular example we choose the artery which is - as most other biological tissues - characterized by anisotropic and nonlinear material properties. We compare two specific approaches of FETI methods, classical and all-floating, and investigate the numerical behavior of different preconditioning techniques. In comparison to classical FETI, the all-floating approach has not only advantages concerning the implementation but in many cases also concerning the convergence of the global iterative solution method. This behavior is illustrated with numerical examples. We present results of linear elastic simulations to show convergence rates, as expected from the theory, and results from the more sophisticated nonlinear case where we apply a well-known anisotropic model to the realistic geometry of an artery. Although the FETI methods have a great applicability on artery simulations we will also discuss some limitations concerning the dependence on material parameters.Comment: 29 page

Effect of Tertiarybutylhydroquinone on the stability of fried banana chips

Perbandingan kestabilan terhadap pengoksidanan ke atas kerepek pisang yang digoreng dalam minyak kelapa sawit olein yang mengandungi antioksidan, tertiary"butylhydroquinone, dan minyak kelapa sawit olein tanpa antioksidan telah dikaji. Nilai-nilai peroksid d{m anisidin bagi minyak yang diekstrak dan kerepek yang disimpan pada suhu 60° C menjelaskan kerepek pisang yang digoreng dalam minyak mengandungi tertiarybu tylhydroquinone memperolehi kestabilan yang lebih baik terhadap jangkamasa penyimpanan bagi kerepek tersebu

Post-harvest Storage of Guava (Psidium guajava, L, var. Taiwan)

Guava fruit (var. Taiwan) were stored at room temperature (26°C), 200e and 50 e and the characteristics of the fruits during storage were evaluated. Guava fruit has a post-harvest life of about 1 week during room temperature storage and post-harvest life can be extended by a few days during storage at 20°C. At 2~ eand 200 e, post-harvest life is limited by the occurrence of rots. At~e, bronzing of the guava skin occurs at about 2 weeks of storage. Rots were not evident during storage at 5°e. The average pH, total soluble solids and titratable acidity of guava at harvest was 3.5,5.4°Brix and 62.8 ml O.lNaOH/ 100g respectively. The levels of individual soluble sugars were: fructose 1.60 g/100g, glucose 1.06g/1 OOg and sucrose O. 78g/1 OOg at the commencement of the study. There were significant increases in total soluble solids during storage at all temperatures. Titratable acidity did not change significantly during storage for 10 days at room temperature and 200 e and during storage for 4 weeks at 5° e. There were significant increases in fructose, glucose and total soluble sugars but no significant differences in sucrose levels during storage at room temperature. Significant increase in fructose levels and total soluble sugar levels were also obtained during storage at 200 e and 5°e. The fructose/glucose ratios significantly increased during storage at all temperatures