Modelling of Adequate Costs of Utilities Services
The paper propose methodology for benchmark modelling of adequate costs of utilities services, which is based on the data analysis of the factual cases (key performance indicators of utilities as the predictors). The proposed methodology was tested by modelling of Latvian water utilities with three tools: (1) a classical version of the multi-layer perceptron with error back-propagation training algorithm was sharpened up with task-specific monotony tests, (2) the fitting of the generalized additive model using the programming language R ensured the opportunity to evaluate the statistical significance and confidence bands of predictors, (3) the sequential iterative nonlinear regression proce…
Confidence Intervals for the Mean Based on Exponential Type Inequalities and Empirical Likelihood
For independent observations, recently, it has been proposed to construct the confidence intervals for the mean using exponential type inequalities. Although this method requires much weaker assumptions than those required by the classical methods, the resulting intervals are usually too large. Still in special cases, one can find some advantage of using bounded and unbounded Bernstein inequalities. In this paper, we discuss the applicability of this approach for dependent data. Moreover, we propose to use the empirical likelihood method both in the case of independent and dependent observations for inference regarding the mean. The advantage of empirical likelihood is its Bartlett correcta…
P5246Nationwide linked administrative data study to explore the variations in statistical classification, management and 30-day mortality of acute myocardial infarctions in Latvia
Abstract Background According to statistics of Organisation for Economic Cooperation and Development (OECD) Latvia has one of the highest 30-day mortality for acute myocardial infarction (AMI). The output data used in the calculation of this indicator was analysed at a hospital level to explain the causes of it. Methods Linked to Causes of death registry administrative reimbursement system data from 2014 to 2017 were analysed. Defined exclusion criteria were applied and 11675 emergency AMI admissions were indexed. As evaluation of the inter-hospital differences in non-ST elevation myocardial infarction (NSTEMI) revealed significant inconsistency in statistical classification of non-ST eleva…
Nitric oxide metabolism is impaired by type 1 diabetes and diabetic nephropathy
Diabetes leads to reduced nitric oxide bioavailability, resulting in endothelial dysfunction. However, overproduction of nitric oxide due to hyperglycaemia is associated with oxidative stress and tissue damage. The objective of this study was to characterise nitric oxide production (NO) and added nitrite and nitrate (NO(2)(-)+NO(3)(-)) concentration in the blood and urine of patients with and without diabetic nephropathy. A total of 268 patients with type 1 diabetes and 69 healthy subjects were included. Diabetic nephropathy was defined as macroalbuminuria and/or estimated glomerular filtration rate below 60 ml/min/1.73 cm(2). NO(2)(-)+NO(3)(-) concentration was measured by Griess reaction.…
Two‐sample problems in statistical data modelling
A common problem in mathematical statistics is to check whether two samples differ from each other. From modelling point of view it is possible to make a statistical test for the equality of two means or alternatively two distribution functions. The second approach allows to represent the two‐sample test graphically. This can be done by adding simultaneous confidence bands to the probability‐probability (P — P) or quantile‐quantile (Q — Q) plots. In this paper we compare empirically the accuracy of the classical two‐sample t‐test, empirical likelihood method and several bootstrap methods. For a real data example both Q — Q and P — P plots with simultaneous confidence bands have been plotted…
Towards evidence-based management: A nationwide administrative data-based audit of acute myocardial infarction in Latvia
When care for an individual patient is determined by evidence-based medical guidelines, the management of the whole clinical process also needs to be based on evidence. In Latvia, an careful retros...
Empirical Likelihood-Based ANOVA for Trimmed Means
In this paper, we introduce an alternative to Yuen’s test for the comparison of several population trimmed means. This nonparametric ANOVA type test is based on the empirical likelihood (EL) approach and extends the results for one population trimmed mean from Qin and Tsao (2002). The results of our simulation study indicate that for skewed distributions, with and without variance heterogeneity, Yuen’s test performs better than the new EL ANOVA test for trimmed means with respect to control over the probability of a type I error. This finding is in contrast with our simulation results for the comparison of means, where the EL ANOVA test for means performs better than Welch’s heteroscedastic…
Angiopoietin 2 and Neuropeptide Y are Associated with Diabetic Kidney Disease in Type 1 Diabetes Mellitus
Abstract Background Serum angiopoietin 2 levels have been associated with endothelial dysfunction and diabetic kidney disease. Derangements in autonomous nervous system lead to increased production of vasoconstrictory and angiogenic mediators such as norepinephrine and neuropeptide Y and are associated with increased risk of microvascular complications. Aim To investigate associations between angiopoietin 2, neuropeptide Y and diabetic kidney disease in patients with type 1 diabetes mellitus. Methods 289 patients with type 1 diabetes mellitus duration > 1 year were included. Patients were stratified according to presence of diabetic nephropathy (macroalbuminuria, estimated glomerular fil…
DNA damage in leukocytes and serum nitrite concentration are negatively associated in type 1 diabetes.
Abstract Chronic hyperglycaemia leads to DNA damage in diabetes and might be associated with nitrosative stress. In this study, we aimed at assessing the level of DNA strand breaks in leukocytes, serum nitrite and nitrate in patients with type 1 diabetes and healthy controls and associations of these parameters with diabetes-related outcomes in a prospective study. The level of DNA damage was determined in 71 patients with type 1 diabetes and 57 healthy controls by comet assay and scored with arbitrary units (AU). The chemiluminescence method was used to measure nitrite and nitrate. Clinical information and data on consumption of alcohol, physical activity and smoking were collected. Progre…
Impact of interval walking training managed through smart mobile devices on albuminuria and leptin/adiponectin ratio in patients with type 2 diabetes
Abstract Background Interval walking training has demonstrated more pronounced positive effects on physical fitness and metabolism in type 2 diabetes (T2D), compared to continuous walking. One of the pathogenic mechanisms of T2D is associated with derangements in leptin/adiponectin axis, which might predispose affected individuals to vascular inflammation and albuminuria. The aim of this study was to investigate the effects of interval walking training delivered through smart mobile devices upon albuminuria and leptin/adiponectin ratio in patients with T2D. Methods Patients with T2D aged 35–75 were randomized into control (n = 26) and interval training (IT, n = 14) groups. Patients in IT gr…
A Cross-Sectional Research on the Height, Weight and Body Mass Index of Children Aged 5-6 Years in Latvia and Its Secular Changes during the Last Century
Aim: To determine the main anthropometric parameters and their changes during the 20th and early 21st centuries for children aged 5-6 and to analyze the nutritional level of the population based on percentage. Methods: 536 healthy Latvian 5 and 6 year old children were randomly selected and a cross sectional survey was carried out. To collect anthropometric data, the height and weight of each child was measured and BMI calculated. The Kolmogorov-Smirnov Goodness-of-Fit test was used to assess the distribution of data; it was concluded, that the data for both boys and girls in both analyzed age groups fits a normal distribution. Using a t-test statistical tool, the results were compared to o…
BICKEL–ROSENBLATT TEST FOR WEAKLY DEPENDENT DATA
The aim of this paper is to analyze the Bickel–Rosenblatt test for simple hypothesis in case of weakly dependent data. Although the test has nice theoretical properties, it is not clear how to implement it in practice. Choosing different band-width sequences first we analyze percentage rejections of the test statistic under H0 by some empirical simulation analysis. This can serve as an approximate rule for choosing the bandwidth in case of simple hypothesis for practical implementation of the test. In the recent paper [12] a version of Neyman goodness-of-fit test was established for weakly dependent data in the case of simple hypotheses. In this paper we also aim to compare and discuss the …