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- Klefsjö, Bengt
(författare)
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Some tests against aging based on the total time on test transform
- 1983
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Ingår i: Communications in Statistics - Theory and Methods. - : Informa UK Limited. - 0361-0926 .- 1532-415X. ; 12:8, s. 907-927
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Tidskriftsartikel (refereegranskat)abstract
- Let F be a life distribution with survival function = 1 - F and finite mean The scaled total time on test transform was introduced by Barlow and Campo (1975) as a tool in the statistical analysis of life data. The aging properties IFR, IFRA, NBUE and DMRL can be translated to properties of ϕF(t). Guided by these properties of ϕF(t) we suggest some test statistics for testing exponentiality against IFR, IFRA, NBUE and DMRL, respectively. The IFR and IFRA tests are new; the NBUE and DMRL tests have already been proposed and stu- died by Hollander and Proschan (1975) . The exact and asymptotic distributions of the statistics are derived and the asymptotic efficiencies of the tests are studied. The power of some tests is estimated by simulation for some alternatives when the sample size is n = 10 or n = 20.
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| 2. |
- Burdakov, Oleg, 1953-
(författare)
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Methods of the secant type for systems of equations with symmetric Jacobian matrix
- 1983
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Ingår i: Numerical Functional Analysis and Optimization. - : Taylor & Francis. - 0163-0563 .- 1532-2467. ; 6:2, s. 183-195
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Tidskriftsartikel (refereegranskat)abstract
- Symmetric methods (SS methods) of the secant type are proposed for systems of equations with symmetric Jacobian matrix. The SSI and SS2 methods generate sequences of symmetric matrices J and H which approximate the Jacobian matrix and inverse one, respectively. Rank-two quasi-Newton formulas for updating J and H are derived. The structure of the approximations J and H is better than the structure of the corresponding approximations in the traditional secant method because the SS methods take into account symmetry of the Jacobian matrix. Furthermore, the new methods retain the main properties of the traditional secant method, namely, J and H-1are consistent approximations to the Jacobian matrix; the SS methods converge superlinearly; the sequential (n + 1)-point SS methods have the R-order at least equal to the positive root of tn+1-tn-1=0.
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| 3. |
- Gardeström, Per, 1950-, et al.
(författare)
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Isolation of Mitochondria from Leaf Tissue of Panicum miliaceum, a NAD-Malic Enzyme Type C(4) Plant.
- 1983
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Ingår i: Plant Physiology. - 0032-0889 .- 1532-2548. ; 71:1, s. 24-9
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Tidskriftsartikel (refereegranskat)abstract
- A mechanical isolation procedure was developed to study the respiratory properties of mitochondria from the mesophyll and bundle sheath tissue of Panicum miliaceum, a NAD-malic enzyme C(4) plant. A mesophyll fraction and a bundle sheath fraction were obtained from young leaves by differential mechanical treatment. The purity of both fractions was about 80%, based on analysis of the cross-contamination of ribulose bisphosphate carboxylase activity and phosphoenolpyruvate carboxylase activity.Mitochondria were isolated from the two fractions by differential centrifugation and Percoll density gradient centrifugation. The enrichment of mitochondria relative to chloroplast material was about 75-fold in both preparations.Both types of mitochondria oxidized NADH and succinate with respiratory control. Malate oxidation in mesophyll mitochondria was sensitive to KCN and showed good respiratory control. In bundle sheath mitochondria, malate oxidation was largely insensitive to KCN and showed no respiratory control. The oxidation was strongly inhibited by salicylhydroxamic acid, showing that the alternative oxidase was involved. The bundle sheath mitochondria of this type of C(4) species contribute to C(4) photosynthesis through decarboxylation of malate. Malate oxidation linked to an uncoupled, alternative pathway may allow decarboxylation to proceed without the restraints which might occur via coupled electron flow through the cytochrome chain.
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| 8. |
- Stubbe, Ingo, et al.
(författare)
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Plasma lipoproteins and lipolytic enzyme activities during endurance training in sedentary men: changes in high-density lipoprotein subfractions and composition
- 1983
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Ingår i: Metabolism, Clinical and Experimental. - : Elsevier BV. - 1532-8600. ; 32:12, s. 1120-1128
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Tidskriftsartikel (refereegranskat)abstract
- Eighteen healthy sedentary males took part in supervised bicycle training for 50 minutes three to five times a week. Twelve subjects (group A) trained for 6 weeks at heavy intensity, and six subjects (group B) trained for 12 weeks at moderate intensity. Maximal oxygen uptake increased by about 20% (P less than 0.01). Body weight and composition as well as diet remained unchanged. After 6 weeks plasma high-density lipoprotein (HDL) cholesterol concentrations had increased by 7% (P less than 0.05) in all subjects. The increase was most marked in group B at 14% (P less than 0.05) compared to 3% in group A (ns). Apolipoprotein AI (apo AI) increased by about 7% in both groups (P less than 0.01). After 12 weeks HDL cholesterol and apo AI levels had almost returned to initial values. Measurements of HDL components showed increases of 6% to 12% in free cholesterol, cholesteryl ester (P less than 0.05), and phospholipid (P less than 0.01); whereas, the minor triglyceride fraction decreased by 20% (P less than 0.01). Zonal ultracentrifugation in four subjects revealed a preferential rise of about 35% in the HDL2 subfraction, increasing the HDL2/HDL3 ratio by about 20%. In parallel, the composition of the lipoprotein classes changed. The protein moiety of all classes, except low-density lipoprotein (LDL), expanded at the expense of the core components cholesteryl ester and triglyceride. Hepatic lipase (HL) activity decreased by 6% (P less than 0.05), and lipoprotein lipase (LPL) activity in adipose tissue increased by about 50% (P less than 0.05) during the first 6 weeks of training, while LPL activity in postheparin plasma and skeletal muscle did not change. The transient rise in HDL cholesterol levels was correlated (P less than 0.05) to the elevation of adipose tissue LPL activity. The alterations in HDL concentration were also related to changes in body composition and diet, especially to an increase in fat intake.
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| 9. |
- Liljeberg, Evelina, 1985-, et al.
(författare)
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Incomplete descriptions of oral nutritional supplement interventions in reports of randomised controlled trials
- 2018
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Ingår i: Clinical Nutrition. - : Elsevier. - 0261-5614 .- 1532-1983. ; 37:1, s. 61-71
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Tidskriftsartikel (refereegranskat)abstract
- Background & aimsThe effects of oral nutritional supplements (ONS) have been evaluated in several clinical trials and more studies have been requested. To facilitate replication, support accurate evaluations of research results and avoid research waste, high quality reporting of interventions in clinical trials is needed. The aim of this study is to assess the quality of reporting of interventions in publications describing randomised controlled trials of ONS in populations with malnutrition or at nutritional risk.MethodsThe PubMed database was searched for articles describing ONS trials published between January 2002 and December 2015. The quality of intervention descriptions was evaluated using the Template for Intervention Description and Replication (TIDieR) checklist and guide, which contains twelve items. Articles published before and after 2011 were compared.ResultsOf 76 articles identified, only 3% reported all TIDieR items in sufficient detail. The most frequently missing elements were descriptions of the intervention procedures (e.g. how the ONS were to be taken and if participants were given a choice of flavours), which were adequately presented in only 26% of the articles. Less than half of the articles included a description of the intervention provider and sufficient information about the location(s) for the intervention. Information about adherence and mode of delivery was reported in 60–65% of the articles. Most frequently reported, in >70% of the articles, were items regarding the brief name of the intervention, the rationale for the intervention and the materials used (i.e. information about the specific ONS product(s) administered). The reporting quality for two of the items (materials and provider) was higher in articles published after 2011.ConclusionsThe quality of reporting of ONS interventions was found to be poor. The descriptions mostly lacked information about intervention procedures, provider and location(s). A moderately higher reporting quality was observed in articles published after 2011. These findings imply that an improvement in the descriptions of ONS interventions is required in future clinical trials of malnutrition treatment.
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| 10. |
- Ashfaq, Awais, 1990-, et al.
(författare)
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Readmission prediction using deep learning on electronic health records
- 2019
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Ingår i: Journal of Biomedical Informatics. - Maryland Heights, MO : Elsevier BV. - 1532-0464 .- 1532-0480. ; 97
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Tidskriftsartikel (refereegranskat)abstract
- Unscheduled 30-day readmissions are a hallmark of Congestive Heart Failure (CHF) patients that pose significant health risks and escalate care cost. In order to reduce readmissions and curb the cost of care, it is important to initiate targeted intervention programs for patients at risk of readmission. This requires identifying high-risk patients at the time of discharge from hospital. Here, using real data from over 7500 CHF patients hospitalized between 2012 and 2016 in Sweden, we built and tested a deep learning framework to predict 30-day unscheduled readmission. We present a cost-sensitive formulation of Long Short-Term Memory (LSTM) neural network using expert features and contextual embedding of clinical concepts. This study targets key elements of an Electronic Health Record (EHR) driven prediction model in a single framework: using both expert and machine derived features, incorporating sequential patterns and addressing the class imbalance problem. We evaluate the contribution of each element towards prediction performance (ROC-AUC, F1-measure) and cost-savings. We show that the model with all key elements achieves higher discrimination ability (AUC: 0.77; F1: 0.51; Cost: 22% of maximum possible savings) outperforming the reduced models in at least two evaluation metrics. Additionally, we present a simple financial analysis to estimate annual savings if targeted interventions are offered to high risk patients. © 2019 The Authors
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