Search results for "Multivariable"
showing 10 items of 39 documents
Identifying Prognostic SNPs in Clinical Cohorts: Complementing Univariate Analyses by Resampling and Multivariable Modeling
2016
Clinical cohorts with time-to-event endpoints are increasingly characterized by measurements of a number of single nucleotide polymorphisms that is by a magnitude larger than the number of measurements typically considered at the gene level. At the same time, the size of clinical cohorts often is still limited, calling for novel analysis strategies for identifying potentially prognostic SNPs that can help to better characterize disease processes. We propose such a strategy, drawing on univariate testing ideas from epidemiological case-controls studies on the one hand, and multivariable regression techniques as developed for gene expression data on the other hand. In particular, we focus on …
Decreased Time to Treatment Initiation for Multidrug-Resistant Tuberculosis Patients after Use of Xpert MTB/RIF Test, Latvia
2016
This test decreased time to treatment initiation by 66%–84%.
Clinical practices to promote sleep in the ICU: A multinational survey
2018
PURPOSE: To describe sleep assessment and strategies to promote sleep in adult ICUs in ten countries.METHODS: Multicenter, self-administered survey sent to nurse managers.RESULTS: Response rate was 66% with 522 ICUs providing data. 'Lying quietly with closed eyes' was the characteristic most frequently perceived as indicative of sleep by >60% of responding ICUs in all countries except Italy. Few ICUs (9%) had a protocol for sleep management or used sleep questionnaires (1%). Compared to ICUs in Northern Europe, those in central Europe were more likely to have a sleep promoting protocol (p < 0.001), and to want to implement a protocol (p < 0.001). In >80% of responding ICUs, the …
Birth weight and adult income : An examination of mediation through adult height and body mass
2021
This paper examines the causal links between early human endowments and socioeconomic outcomes in adulthood. We use a genotyped longitudinal survey (Cardiovascular Risk in Young Finns Study) that is linked to the administrative registers of Statistics Finland. We focus on the effect of birth weight on income via two anthropometric mediators: body mass index (BMI) and height in adulthood. We find that (i) the genetic instruments for birth weight, adult height, and adult BMI are statistically powerful; (ii) there is a robust total effect of birth weight on income for men but not for women; (iii) the total effect of birth weight on income for men is partly mediated via height but not via BMI; …
Extension of The Stochastic Differential Calculus To Complex Processes
1996
In structural engineering complex processes arise to predict the first excursion failure, fatigue failure, etc. Indeed to solve these problems the envelope function, which is the modulus of a complex process, is usually introduced. In this paper the statistics of the complex response process related to the envelope statistics of linear systems subjected to parametric stationary normal white noise input are evaluated by using extensively the properties of stochastic differential calculus.
Land surface air temperature retrieval from EOS-MODIS images
2014
The knowledge of the spatial and temporal patterns of surface air temperature (SAT) is essential to monitor a region's climate and meteorology, to quantify surface exchange processes, to improve climatic and meteorological model results, and to study health and economic impacts. This letter analyzed correlations between SAT and geophysical land surface variables, mainly land surface temperature (LST), to establish operative techniques to obtain spatially continuous land SAT maps from satellite data, unlike data provided by meteorological station networks. The correlations were analyzed by using EOS-MODIS images, meteorological station network data, and geographical variables. Linear regress…
Estrategias para la elaboración de modelos estadísticos de regresión
2011
Multivariable regression models are widely used in health science research, mainly for two purposes: prediction and effect estimation. Various strategies have been recommended when building a regression model: a) use the right statistical method that matches the structure of the data; b) ensure an appropriate sample size by limiting the number of variables according to the number of events; c) prevent or correct for model overfitting; d) be aware of the problems associated with automatic variable selection procedures (such as stepwise), and e) always assess the performance of the final model in regard to calibration and discrimination measures. If resources allow, validate the prediction mo…
Bayesian classification for dating archaeological sites via projectile points
2021
Dating is a key element for archaeologists. We propose a Bayesian approach to provide chronology to sites that have neither radiocarbon dating nor clear stratigraphy and whose only information comes from lithic arrowheads. This classifier is based on the Dirichlet-multinomial inferential process and posterior predictive distributions. The procedure is applied to predict the period of a set of undated sites located in the east of the Iberian Peninsula during the IVth and IIIrd millennium cal. BC.
THE RELATIONSHIP BETWEEN CIVIC FACTORS AND THE MIDDLE PROFICIENCY LEVEL OF CIVIC KNOWLEDGE
2021
This study explores the relationship between civic and citizenship factors and the middle proficiency level of students’ civic knowledge in the Baltic countries: Estonia, Latvia and Lithuania. The study uses large scale data from the IEA’s International Civic and Citizenship Education Study (ICCS) 2016. According to ICCS 2016, 39% of students from the three Baltic countries and only 26% of students from the Nordic countries had a middle proficiency level of civic knowledge. This middle proficiency level is the largest group in comparison to other levels. Therefore, the study aims to recognise the differences between the highest and lowest achievements in the middle proficiency level of civi…
Linear Regression Analysis
2010
SUMMARY Background: Regression analysis is an important statistical method for the analysis of medical data. It enables the identification and characterization of relationships among multiple factors. It also enables the identification of prognostically relevant risk factors and the calculation of risk scores for individual prognostication. Methods: This article is based on selected textbooks of statistics, a selective review of the literature, and our own experience. Results: After a brief introduction of the uni- and multivariable regression models, illustrative examples are given to explain what the important considerations are before a regression analysis is performed, and how the resul…