Study of Bootstrap Estimates in Cox Regression Model with Delayed Entry

summary:In most clinical studies, patients are observed for extended time periods to evaluate influences in treatment such as drug treatment, approaches to surgery, etc. The primary event in these studies is death, relapse, adverse drug reaction, or development of a new disease. The follow-up time may range from few weeks to many years. Although these studies are long term, the number of observed events is small. Longitudinal studies have increased the importance of statistical methods for time-to event data that can incorporate time-dependent covariates. The Cox proportional regression model is a widely used method. It is a statistical technique for exploring the relationship between the survival of a patient and several explanatory variables. We apply Cox regression models when right censoring and delayed entry survival data are considered. Su and Wang (2012) stated that delayed entry produced biased sample. In the paper we present how re-sampling together with effect of delayed entry affect estimated parameters. The possibilities as well as limitations of this approach are demonstrated through the retrospective study of mitral valve replacement in children under 18 years

Appropriateness of gait analysis for biometrics: Initial study using FDA method

Human body movement has been under continuous research for many years due to its potential application as a novel biometric system to identify individuals. It is possible to utilize various techniques, not only to obtain requested movement data, but also to analyse movement data. This paper uses functional data analysis on data obtained from 12 volunteers and uses 20 markers from the 3D motion capture system VICON MX T020. The functional data analysis was chosen as a suitable tool to obtain more information about an individual's movement because it uses a technique for real-time data, which corresponds to continuous time process. The results show that all markers, under any walking speed and condition, identify a significantly high percentage of individual pairs. Further, our results discriminate between markers, where some markers are highly dependent on walking speed and condition, and also on the influence of body part asymmetry. In addition, regular movement patterns in almost all participants’ data shows a potential to identify individuals based on gait recognition with a 1:1 matching result. © 2017 Elsevier LtdIGA grant at Tomas Bata University in Zlin [IGA/FAI/2013/001]; European Regional Development Fund under the project CEBIA-Tech [CZ.1.05/2.1.00/03.0089]; Grant Agency of the Czech Republic [GA15-06991S]; Scientific Grant Agency of the Ministry of Education of the Slovak Republic; Slovak Academy of Sciences [VEGA 2/0011/16]; Slovak Research and Development Agency [APVV-15-0295

Mathematical aspects of the kriging applied on landslide in Halenkovice (Czech Republic)

Kriging is one of the geostatistical techniques for spatial data analysis that is usually used for a modelling of natural phenomena or a creation of digital elevation models. In this paper, we introduce kriging methods in the context of a landslide modelling in time. The proposed procedure, as well as most of the statistical methods, is designed for complete data sets, i.e. the observations at the beginning and the end of the study are available. In order to use all the information from the data and to avoid the loss of information after omitting observations with missing values, the algorithm for imputation of missing data values based on kriging techniques is proposed. The methodology was verified by the landslide modelling in Halenkovice, Czech Republic, during the period from June 2008 to March 2010. The obtained results showed a potential of kriging methods for the landslide modelling. © R. Zůvala et al., published by De Gruyter Open.Operational Program Education for Competitiveness - European Social Fund (Ministry of Education, Youth and Sports of the Czech Republic) [CZ.1.07/2.3.00/20.0170]; Internal Grant Agency of Palacky University in Olomouc [IGA_PrF_2015_013

Survival analysis of factors influencing cyclic fatigue of nickel-titanium endodontic instruments

Objective. The aim of this study was to validate a survival analysis assessing the effect of type of rotary system, canal curvature, and instrument size on cyclic resistance. Materials and Methods. Cyclic fatigue testing was carried out in stainless steel artificial canals with radii of curvature of 3 or 5 mm and the angle of curvature of 60 degrees. All the instruments were new and 25 mm in working length, and ISO colour coding indicated the instrument size (yellow for size 20; red for size 25). Wizard Navigator instruments, Mtwo instruments, ProTaper instruments, and Revo-S instruments were passively rotated at 250 rotations per minute, and the time fracture was being recorded. Subsequently, fractographic analysis of broken tips was performed by scanning electron microscope. The data were then analysed by the Kaplan-Meier estimator of the survival function, the Cox proportional hazards model, the Wald test for regression covariates, and the Wald test for significance of regression model. Conclusion. The lifespan registered for the tested instruments was Mtwo > Wizard Navigator > Revo-S > ProTaper; 5 mm radius > 3 mm radius; and yellow > red in ISO colour coding system.Ministry of Education, Youth and Sports of the Czech Republic [CZ.1.07/2.3.00/20.0170, CZ.1.07/2.3.00/30.0041

Reduce the sulphur dioxide content of wine by biological process in relation to the content of polyphenolic substances

In recent years, many papers have paid attention to the bioactive compounds, particularly to the antioxidant activity of polyphenolic compounds in food and beverages, due to their positive effect on human body. Therefore, the phenolic compounds and their antioxidant capacity become an important quality parameter, especially in niche markets concerned with health benefits. Wine is an excellent source of various classes of polyphenols. The phenolic compounds are responsible for the sensory characteristics, particularly colour, astringency, bitterness, and aroma, too. Another very important ingredient in the wine is added the sulphur dioxide, which has the role to protect these reductive components of wines. Sulphur dioxide has the effects of antioxidant, antimicrobial and preservative that is mutually merging. However, it is possible to increase the stability of the complex of biologically active substances (BAS), as holders of natural antioxidant capacity. The present contribution brings opportunities rather than full elimination, but a substantial reduction of the content of sulphur dioxide, which protects the wine during the entire technological process of manufacture and treatment. The dosage of sulphur dioxide can be reduced in its values from 15 to 40% of the total health of the authorized maximum sulphur dioxide content of wine.operational Program called Research and Development for Innovations (Vyzkum a vyvoj pro inovace); state budget of the Czech Republic within the Centre of Polymer Systems Project [CZ.1.05/2.1.00/03.0111]; Brno University of Technology - MSMT CR [22738]; European Fund for Regional Development (ERDF)European Commissio

Non-ideal development of the hip joint as a forming factor of idiopathic scoliosis

The thesis deals with connections between non-ideal development of the hip joint and origin of idiopathic scoliosis. The thesis warn that asymmetry in neuromotor ontogenesis is a risk factor for development of scoliosis. There is also summary of abnormalities in hip joints which are connected with idiopatic scoliosis. In experimental part of the work it has been confirmed that patient with idiopathic scoliosis have leftright asymmetry of the range of movement in hip joints. This asymmetries are discussed in the context of both the etiopathogenezis and the effect of spinal deformity. Powered by TCPDF (www.tcpdf.org

Non-ideal development of the hip joint as a forming factor of idiopathic scoliosis

The thesis deals with connections between non-ideal development of the hip joint and origin of idiopathic scoliosis. The thesis warn that asymmetry in neuromotor ontogenesis is a risk factor for development of scoliosis. There is also summary of abnormalities in hip joints which are connected with idiopatic scoliosis. In experimental part of the work it has been confirmed that patient with idiopathic scoliosis have leftright asymmetry of the range of movement in hip joints. This asymmetries are discussed in the context of both the etiopathogenezis and the effect of spinal deformity. Powered by TCPDF (www.tcpdf.org

Setting-Out of the Linear Part of High-Speed Lane

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Trade mark law and the issues of parallel imports under Czech law

IN ENGLISH Trade mark law and the issues of parallel imports under Czech law The purpose of the thesis is to analyze the trade mark law and the issues of parallel imports under Czech law. The thesis describes the present situation in the Czech Republic, points out the influence of the European Union and considers the impact of the current regulation of parallel imports concerning trademarked goods. The paper also focuses on the court decisions of the Court of Justice of the European Union which have great effect on the law effective in the Czech Republic. The reason for my research is the ongoing international discussion on that topic and the necessity to find balance among contrary interests of trademark owners, parallel importers and consumers. The aim of the thesis is presented at the beginning. The next chapter of the thesis is introductory and defines basic terminology in general. The third chapter looks at the Czech legislation connected to the topic and highlights its connection to the European law. The next section analyzes the law of the European Union and is subdivided into three parts. The first part outlines the historical context and sets out the basic facts. The next part is concerned with a leading principle used in the European Union - the principle of community exhaustion. The last..