bluuebunny/crossref_metadata_2025 huggingface dataset:
Student ability assessment based on two IRT models
Authors: Cagnone Silvia , Ricci Roberto
Published: December 2021

The aim of this work is to analyze a part of the data collected in the Computer Science Department during the Informatics exams in the year 2003. Two different Item Response Theory models for ordered polytomous variables are considered in order to get an evaluation of student ability. Ordered polytomous variables are used for a problem solving process that contains a finite number of steps so that the ability of a student can be evaluated on the basis of the step achieved, namely, higher steps achieved are related to higher ability. The models considered are the Partial Credit Model and the Graded Response Model. The choice of these models has been dictated by the fact that although they are defined into different theoretical frameworks, the former belongs to the Rasch family (Masters, 1982) and the latter can be viewed as a Generalized Linear Latent Variable Model (Bartholomew and Knott, 1999), and hence they present different properties, both of them allow to treat ordinal observed variables. The analysis of the real data set through the two approaches allows to highlight their advantages and disadvantages.
Symbolic covariance matrix for interval-valued variables and its application to principal component analysis
Authors: Košmelj Katarina , Le-Rademacher Jennifer , Billard Lynne
Published: December 2021

In the last two decades, principal component analysis (PCA) was extended to interval-valued data; several adaptations of the classical approach are known from the literature. Our approach is based on the symbolic covariance matrix Cov for the interval-valued variables proposed by Billard (2008). Its crucial advantage, when compared to other approaches, is that it fully utilizes all the information in the data. The symbolic covariance matrix can be decomposed into a within part CovW and a between part CovB. We propose a further insight into the PCA results: the proportion of variance explained due to the within information and the proportion of variance explained due to the between information can be calculated. Additionally, we suggest PCA on CovB and CovW to be done to obtain deeper insights into the data under study. In the case study presented, the information gain when performing PCA on the intervals instead of the interval midpoints (conditionally the means) is about 45%. It turns out that, for these data, the uniformity assumption over intervals does not hold and so analysis of the data represented by histogram-valued variables is suggested.
Women's job search propensity and selection effect in European labour markets
Authors: Castellano Rosalia , Punzo Gennaro
Published: December 2021

The aim of this paper is to explore the main determinants of women's job search propensity and the mechanism underlying the selection effect into labour markets. The analysis compares the European countries, sharing the lowest female activity rates, with the well-developed economies of North Europe, traditionally characterized by the highest levels of female labour force participation. The potential selection bias due to the overlap in some unobserved characteristics is addressed via a bivariate probit model. Significant selection effects in women's job search process of opposite signs are found for Greece, on the one side, and for the Polish and the Norwegian labour markets, on the other one.
Using machine learning to predict the impact of agricultural factors on communities of soil microarthropods
Authors: Demšar Damjan , Džeroski Sašo , Henning Krogh Paul , Larsen Thomas
Published: December 2021

With the newly arisen ecological awareness in the agriculture the sustainable use and development of the land is getting more important. With the sustainable use of soil in mind, we are developing a decision support system that helps making decisions on managing agricultural systems and is able to handle both conventional and genetically modified crops as a part of the ECOGEN project. The decision support system considers economical and agricultural factors and actions including crop selection, crop sequence, pest and weed control actions etc. For such decision support system to work, it needs modules that predict results of different agricultural actions. One of the most important factors for sustainable use and fertility of soil is soil flora and fauna. Any change of that community can influence the short or long term soil fertility and soil usability. With soil fauna being one of the most important factors we first need to model it. However, since the function of the individual species is not known, the only action we have is to try and model the community of soil fauna. We start by modelling the community soil microarthropods. For that goal we used machine learning methods - regression trees, model trees and linear equations. We identified previous crops and time since different kinds of tillage as the most important factors for the community of soil microarthropods.
How (not) to measure social support networks
Authors: Hlebec Valentina , Kogovšek Tina
Published: December 2021

The name generator approach and the role relation approach are among the most common ways to measure ego-centered social networks. The name generator approach, which first requires of a respondent to name actual persons and then usually asks several additional questions about these persons gives richer data on the respondent's social network, but is, on the other hand, relatively costly and burdensome. On the other hand the role relation approach is simpler to use and probably less burdensome for the respondent (he/she names persons in his/her networks only in terms of their roles, e.g., partner, friend), but provides less precise data on the respondent's network (e.g., network composition and size). Previous experiments which compared both approaches with regard to network composition (proportions of family, friends, neighbors and co-workers) provide incomplete evidence because the two approaches differed in several methodological aspects (e.g., question wording, limitation of the number of named alters, ranking of named alters). In this article, an experiment was designed in which all factors that were found to interact with network composition and the two approaches were controlled for. Based on previous studies, several hypotheses were formulated and tested. Data were collected on a quota sample of 683 respondents by students at the Faculty of Social Sciences and the Faculty of Arts in Ljubljana in October and November 2008. Results show that, in general, differences in frequency distributions were not large. Provision of instrumental support is similar for both approaches, but larger differences appear in emotional, informational and work support. Differences were greater for strong ties and for the category "no one". Differences were also slightly larger for first choices. Dispersion of roles was slightly greater with the name generator approach. Results are discussed in comparison with previous findings.
Recent decline in life expectancy at birth in Slovenia
Authors: Lotrič Dolinar Aleša , Sambt Jože
Published: December 2021

For many decades, life expectancy at birth (e0) in Slovenia has been increasing at a very rapid pace. However, in 2015, e0 declined slightly; it recovered in 2016, but fell again in 2017 for women. In the same period, a pause in declining mortality was observed in numerous developed countries worldwide. It is too early to provide a thorough analysis and firm conclusions, but we shed some light on the topic by decomposing the observed decline in Slovenia by age and cause of death. In particular, using a life table model and life expectancy decomposition technique, we analyse what cause of death for what age group contributed the most to this decline in life expectancy at birth. We show that the main reason for the recent drop in life expectancy at birth in Slovenia was higher mortality due to external causes for men of all ages and due to neoplasms for women above 60 years and men above 50 years.
Allowing examinee choice in educational testing
Authors: Cankar Gašper
Published: December 2021

Achievement tests sometimes entertain examinee choice – a situation where an examinee is presented with a set of items among which s/he has to choose one (or few) to answer that will be scored in her/his total test score. Basic assumption is that choice items are equivalent regarding both content and psychometric characteristics and therefore it doesn't matter which particular item examinee selects. Choice items often also share same maximum number of points and examinee score on a test is usually achieved by summing scores from all items taken by the examinee regardless of their combination. Choice items present conceptual problems like why enabling choice when items should be equivalent in the first place and methodological ones like how item scores from different combinations of items should contribute to comparable total score on test. Author used Rasch's model within Item Response Theory framework to test the assumption of equivalence of choice items by scaling all item difficulties on same scale. Physics 2008 and 2009 tests from Slovenian General Matura examination are analyzed as an example to explore equivalence of choice items. Differences in difficulty of choice items in those tests are presented and discussed. It seems that examinee choice still doesn't work in educational testing and should be avoided when possible.
Mallows' L2 distance in some multivariate methods and its application to histogram-type data
Authors: Košmelj Katarina , Billard Lynne
Published: December 2021

Mallows' L2 distance allows for decomposition of total inertia into within and between inertia according to Huygens theorem. It can be decomposed into three terms: the location term, the spread term and the shape term; a simple and straightforward proof of this theorem is presented. These characteristics are very helpful in the interpretation of the results for some distance-based methods, such as clustering by k-means and classical multidimensional scaling. For histogram-type data, Mallows' L2 distance is preferable because its calculation is simple, even when the number and length of the histograms' subintervals differ. An illustration of its use on population pyramids for 14 East European countries in the period 1995–2015 is presented. The results provide an insight into the information that this distance can extract from a complex dataset.
Latent class analysis identification of syndromes in Alzheimer's disease
Authors: Walsh Cathal
Published: December 2021

Latent variable models have been used extensively in the social sciences. In this work a latent class analysis is used to identify syndromes within Alzheimer's disease. The fitting of the model is done in a Bayesian framework, and this is examined in detail here. In particular, the label switching problem is identified, and solutions presented. Graphical summaries of the posterior distribution are included.
Modelling of patterns and estimation of characteristic parameters
Authors: Borštnik Bračić Anamarija , Grabec Igor , Govekar Edvard
Published: December 2021

A two-dimensional pattern represents a fingerprint of the process that generated it. It is therefore expected that the information about the production process can be extracted from the pattern. In this paper, a non-parametric statistical method for modelling chaotic two-dimensional patterns and the estimation of the characteristic parameters is proposed. It is based on the joint probability density function of samples taken from known two-dimensional patterns representing a database. A new pattern with an unknown production process is reproduced by comparing parts of the new pattern with samples taken from the database. Because the samples in the database also include information about the production process, relevant parameters and the type of production process can be estimated simultaneously with the reproduction of patterns.
X-bar control chart for non-normal symmetric distributions
Authors: Veljković Kristina
Published: December 2021

In statistical quality control, X-bar control chart is extensively used to monitor a change in the process mean. In this paper, X-bar control chart for non-normal symmetric distributions is proposed. For chosen Student, Laplace, logistic and uniform distributions of quality characteristic, we calculated theoretical distribution of standardized sample mean and fitted Pearson type II or type VII distributions. Width of control limits and power of the X-bar control chart were established, giving evidence of the goodness of fit of the corresponding Pearson distribution to the theoretical distribution of standardized sample mean. For implementation of X-bar control chart in practice, numerical example of construction of a proposed chart is given.
Effects of the same-gender vs. cross-gender mentoring on a protégé outcome in academia
Authors: Kogovšek Metka , Ograjenšek Irena
Published: December 2021

Mentoring seems to be an important way to start and advance individual researcher's career in science. Therefore, it is essential to examine the factors related to successful mentoring in order to find ways of efficiently supporting young academics on their career development path. Building on the similarity-attraction and social identity theories, our research indicates that gender similarity in academic mentoring might be related to the protégés' postdoctoral publication scores that lead to career advancement. The scores in a typical five-year publication cycle are higher for the protégés situated within same-gender mentoring dyads. Furthermore, the mentors' research performance importantly adds to the protégés' postdoctoral research performance.
Absent ties in social networks, their treatments, and blockmodeling outcomes
Authors: Žnidaršič Anja , Doreian Patrick , Ferligoj Anuška
Published: December 2021

An absent tie is one for which we have no information regarding its nature. Absent ties for a network is a set of such ties. This lack of information can be present anywhere in network data and has the potential to compromise the results of all network analytic tools. To assess this impact, we used real networks and based simulations on them by introducing varying amounts of absent ties. They were treated with four treatments of absent ties. Blockmodeling, using structural equivalence, was applied to the known networks and then to every treated network. The results were compared. The amount of absent ties, their treatments, the block structure of a network, and the level of reciprocity all have an effect of the adequacy of the results of blockmodeling. Reconstruction combined with imputation based on modal values was the best overall treatment. However, treatments of absent ties can work for some networks but not others and we recommend treatments of absent ties based on the form of networks.
Ratio of two random variables
Authors: Cedilnik Anton , Košmelj Katarina , Blejec Andrej
Published: December 2021

To enable correct statistical inference, the knowledge about the existence of moments is crucial. The objective of this paper is to study the existence of the moments for the ratio \(Z = X/Y\) , where \(X\) and \(Y\) are arbitrary random variables with the additional assumption \(P(Y = 0) = 0\). We present three existence theorems showing that specific behaviour of the distribution of \(Y\) in the neighbourhood of zero is essential. Simple consequences of these theorems give evidence to the existence of the moments for particular random variables; some of these results are well known from standard probability theory. However, we obtain them in a simple way.
Comparing social networks
Authors: Faust Katherine
Published: December 2021

This paper demonstrates limitations in usefulness of the triad census for studying similarities among local structural properties of social networks. A triad census succinctly summarizes the local structure of a network using the frequencies of sixteen isomorphism classes of triads (sub-graphs of three nodes). The empirical base for this study is a collection of 51 social networks measuring different relational contents (friendship, advice, agonistic encounters, victories in fights, dominance relations, and so on) among a variety of species (humans, chimpanzees, hyenas, monkeys, ponies, cows, and a number of bird species). Results show that, in aggregate, similarities among triad censuses of these empirical networks are largely explained by nodal and dyadic properties – the density of the network and distributions of mutual, asymmetric, and null dyads. These results remind us that the range of possible network-level properties is highly constrained by the size and density of the network and caution should be taken in interpreting higher order structural properties when they are largely explained by local network features.
Modelling moving feasts determined by the Islamic calendar
Authors: Grun Rehomme Michel , Ben Rejeb Amani
Published: December 2021

National and religious events always influence economic activity. Islamic events also influence production and consumption. Moreover, these Islamic feasts move over time, depending on the Hegirian calendar, which is based on the lunar cycles, even though, some Islamic countries use officially the Gregorian calendar. The lunar calendar is shorter than the Gregorian calendar, which is based on the cycles of the Earth revolution. Consequently, every year the dates of religious events change in the official calendar creating moving events. Tunisia offers a good example of this phenomenon. Twelve relevant series are analysed and five feasts are considered in our work. Modelling the effect of moving holidays improves the quality of the final adjustment. Removing Islamic feasts from time series is crucial to have better forecasting and comparison results. We adopt an approach initially developed by Bell and Hillmer (1983) to analyse the Easter effect. Since the effect is not the same, we consider three regressors for before, during, and after the holiday for each feast. For model selection and determining the number of regressors and their interval length, two methods are used: the F-adjusted Akaike's information criterion and a criterion based on forecast errors. The empirical results confirm our model selection for all the macroeconomic time series considered except for the exports and the broad money which are not affected by the religious feasts.
A-optimal chemical balance weighing design under certain condition
Authors: Ceranka Bronisław , Graczyk Małgorzata
Published: December 2021

The paper is studying the estimation problem of individual weights of \(p\) objects using the design matrix \(\mathbf{X}\) of the A-optimal chemical balance weighing design under the restriction \(p_1 + p_2 = q  \leq p\), where \(p_1\) and \(p_2\) represent the number of objects placed on the left pan and on the right pan, respectively, in each of the measurement operations. The lower bound of \(\mathrm{Tr}(\mathbf{X}^{\prime}\mathbf{X})^{-1}\) is attained and the necessary and sufficient conditions for this lower bound to be obtained are given. There are given new construction methods of the A-optimal chemical balance weighing designs based on incidence matrices of the balanced bipartite weighing designs and the ternary balanced block designs.
first look on smaller sized samples for bootstrap derived patterns of profile analysis via multidimensional scaling
Authors: Bratkovič Patrik
Published: December 2021

The possibility of using small sized samples was investigated for bootstrapping validation of scale values in Profile Analysis via Multidimensional Scaling (PAMS). Three original samples using three different psychological test batteries served as a basis for the investigation; TEMPS-A (N = 1167), BFQ (N = 347), and ICID (N = 565). Each of these samples were then randomly split into three smaller sizes (n = 50, n = 100, n = 200), and the original sample size (N = Full) was included as well. All four sample sizes were submitted to a bootstrapping procedure with 1000 resamples with replacement, and each bootstrapped resample was analyzed with multidimensional scaling (MDS) to create two major profiles in PAMS. The resulting scale values, i.e. the coordinates from MDS, were analyzed using the bootstrapped distributions confidence intervals (CI). The smaller samples' CIs were compared towards the ones of the full sample to investigate invariance using Chebyshev's rule. The results indicate that the n = 200 samples were all invariant in comparison with the original sample sizes and produce reasonable results when the goal is to extract major profiles via bootstrapped confidence intervals using PAMS.
Clustering of population pyramids using Mallows' L2 distance
Authors: Košmelj Katarina , Billard Lynne
Published: December 2021

In many real situations, data are collected/presented as histograms. Such examples are population pyramids, which present the age distribution of a population by gender for a particular country. The objective of this paper is to partition countries into homogenous groups according to the similarity of the shape of the population pyramids in each particular year and to observe the time-trend. We use a Mallows' L2 distance for this purpose. A case study on East European countries in the period 1995–2015 is presented. The results reflect that the countries are becoming more and more similar and follow a pattern of aging populations. For the majority of countries, this process started long before 1990, for Kosovo, Albania and Macedonia it started after 1990.
Effect of rounding on expected value and standard deviation
Authors: Cedilnik Anton , Košmelj Katarina
Published: December 2021

We prove that the rounded expected value of the rounded random variable differs from the expected value of the original random variable by less then 2δ, where δ is the distance between two neighbouring rounded numbers. The same conclusion holds for standard deviation. Hence, in practice the influence of rounding to expected value and standard deviation is almost negligible.
Less parametric methods in statistics
Authors: Weldon Laurence
Published: December 2021

Despite forty years of revolution in the tools available for statistical analysis, the current academic tradition in statistics is remarkably similar to the pre-computer tradition. This tradition is rooted in parametric modeling, estimation, and testing, and optimal procedures based on these models. The paper argues for a shift in emphasis away from parametric modeling and estimation to graphical summary, from omnibus optimal techniques to those that are more context-specific, and from goals of objectivity to goals of revelation. It is suggested that the emphasis in statistical education should be rebalanced to reflect certain modern computer-based techniques.
epidemiological application of a Bayesian nonparametric smoother based on a GLMM with an autoregressive error component
Authors: Zuccolo Luisa , Maule Milena , Gregori Dario
Published: December 2021

Temporal variations in the incidence of rare diseases are a subject of great interest to epidemiologists, who look for recognizable patterns and associations with putative causal factors in order to gain aetiological clues. These data are typically characterised by overdispersion and correlated errors, nevertheless the standard method of analysis in this field has so far been the Poisson regression. The aim of this preliminary study was to suggest the novel employment of a Bayesian nonparametric model (based on a GLMM), a validated statistical approach, to the context of the estimation of childhood cancer incidence trends. The model includes fixed effect terms (age and year of diagnosis) and a random effect vector, intended to represent smooth variation over time, specified in the forward direction as a second order Gaussian autoregressive component. The best use for the model proposed is as "early warning" to epidemiologists for the identification of changes in trends. This and similarly flexible models are in fact characterised by high sensitivity to changes of behaviour; the price we must pay for such high a sensitivity being low specificity.
Estimating poverty in the Italian provinces using small area estimation models
Authors: Quintano Claudio , Castellano Rosalia , Punzo Gennaro
Published: December 2021

Sample survey data are broadly used to provide direct estimates of poverty for the whole population and large areas or domains. That is one of the main deficiencies of poverty analysis at a sub-national level (i.e., related either to regions, or provinces). As they are considered very small geographical areas, since the domain-specific sample is not large enough to support direct estimates of adequate precision, they are likely to produce large standard errors, due to the unduly small size of the sample in that area (Ghosh & Rao, 1994). The aim of our paper is to improve the estimation process quality, in terms of efficiency, of some poverty measures for Italian provinces (NUTS3). The adopted approach deals with Area Level Random Effect Model (Fay & Herriot, 1979) which relates small area direct estimators to domain specific covariates, considering the random area effects as independent. Under that model, the Empirical Best Linear Unbiased Predictor (EBLUP) is obtained. We extend the analysis beyond the conventional measures of income poverty that simply dichotomise the population into the "poor" and the "non poor" by a threshold value and we also consider a fuzzy monetary measure treating poverty as a matter of degree (Cheli & Lemmi, 1995; Cheli, 1995). Through such an analysis, we determine some of the socio-economic factors contributing to poverty levels and living standards, and we investigate in depth the territorial perspective. In order to evaluate the performance of the estimation process through small area models and, consequently, the contribution of auxiliary information to composite poverty estimates, we have defined some outcome measures and some quality indicators (Rao, 2003) have been computed. They allow us to test the extent to which the modelling modifies the input direct estimates and the degree of improvement in the accuracy level of the estimates provided by modelling and, more generally, to evaluate the performance of small area estimators.
Design and development of the income measures in the European Social Surveys
Authors: Hoffmeyer-Zlotnik Juergen , Warner Uwe
Published: December 2021

In social surveys "total net household income" is an indicator of the re-spondent's socio-economic status. It describes the economic situation of household members and their positions in an income distribution. It is used as an explanatory variable in mobility studies and as a social-demographic back-ground item in inequality research. This paper shows the impact of questionnaire design on measurements of "total net household income" in social surveys. In particular we illustrate how the measurement quality of the income variable depends on the data sources about the national income distributions used to design the answer categories offered to the respondent. Beginning with the fourth round of European Social Survey fielded in 2008 and the following years, the income categories for the question about the "total net household income" amount are built on national income distribution of households resident in the country under study. The response categories of the modified ESS questionnaires have been based on deciles of the actual household income distribution in the country in question. The central organizers of European Social Survey (ESS) instruct the national questionnaire designers to define the income brackets for the answer categories using the deciles of the most reliable national income data source. Analyzing the ESS data from 2008, 2010 and 2012, we found in some countries remarkable divergences from the expected 10% frequencies in each category. In this article we argue that the quality of this new income measure depends on the quality of the reference statistics from which the national household income ranges are derived. The quality of the responses to the survey question about the "total net household income", and finally the quality of the obtained survey measure, depends on the quality of the reference statistics from which the household income categories for the answers is derived. These reference data must cover all types of the household's income from all household members and optimally represent the national distribution of household income across the survey universe. That means first that all possible payments accruing to a household and all its members in a given country must be reported in references, and second that all households in the survey's universe must be represented in the statistics used to detect the answer categories. Then the income brackets for the response categories can be calculated using the 10% percentiles from the income distribution in the reference data. Relevance, accuracy, timeliness, comparability, coherence, accessibility and clarity are quality domains of official statistics used as reference data for the survey measurement. We conclude that the central coordinators of the ESS define and communicate minimum threshold values for quality domains of the reference data. The national coordinators should report deviations. This would give the users of ESS data an insight into the quality of the income measurement.
Using canonical correlations in testing for common nonlinear components
Authors: Kavkler Alenka , Böhm Bernhard
Published: December 2021

The paper discusses the use of canonical correlations for modelling multiple equation systems with common nonlinear components of a smooth transition type. The coefficients in a smooth transition regression model are assumed to be nonlinear continuous functions of a properly chosen transition variable. The obtained model thus captures structural changes in the relationship between the observed economic variables. With the help of the canonical correlations technique a simple test for testing for common nonlinear components helps us interpret the relationships between different economic variables and also simplifies the specification and estimation of the equation system, since in this case a reduction in the dimension of nonlinear components is possible. It was shown by Anderson and Vahid (1998) that the test for common nonlinearities is related to the test statistic for the overidentifying restrictions in the generalized method of moments framework and that both tests have the same asymptotic distribution. As an application of the described modelling approach, a three-variable linear vector autoregressive (VAR) model of the consumer price index for Slovenia and Austria and the nominal exchange rate between the currencies of both countries is investigated. A single common nonlinear component is detected in all 3 equations and the estimated multivariate logistic smooth transition autoregressive model is discussed.
quality of survey questions published on Slovenian journalistic web sites
Authors: Ličen Simon , Lozar Manfreda Katja , Hlebec Valentina
Published: December 2021

Some journalistic web sites regularly publish survey questions or polls on current public opinion issues. The goal of these surveys is primarily to entertain the visitors and increase the number of visits. However, these surveys may also shape public awareness and opinion. Therefore, the quality of these survey questions is not to be neglected. We studied the quality of survey questions and response alternatives published on three Slovenian journalistic web sites. The quality of the analyzed survey questions and response alternatives was evaluated using an expert evaluation scheme as checklist. The most striking deficiencies of both survey questions and sets of response alternatives are presented and described. We show that the quality of these questions is often low in comparison to professional survey questions that are used in social science research.
Associations among similarity and distance measures for binary data in cluster analysis
Authors: Cibulková Jana , Šulc Zdenek , Řezanková Hana , Sirota Sergej
Published: December 2021

The paper focuses on similarity and distance measures for binary data and their application in cluster analysis. There are 66 measures for binary data analyzed in the paper in order to provide a comprehensive insight into the problematics and to create their well-arranged overview. For this purpose, formulas by which they were defined are studied. In the next part of the research, the results of object clustering on generated datasets are compared, and the ability of measures to create similar or identical clustering solutions is evaluated. This is done by using chosen internal and external evaluation criteria, and comparing the assignments of objects into clusters in the process of hierarchical clustering. The paper shows which similarity measures and distance measures for binary data lead to similar or even identical results in hierarchical cluster analysis.
Comparing the "typical score" across independent groups based on different criteria for trimming
Authors: Syed Yahaya Sharipah , Othman Abdul , Keselman Harvey
Published: December 2021

Nonnormality and variance heterogeneity affect the validity of the traditional tests for treatment group equality (e.g. ANOVA F-test and t-test), particularly when group sizes are unequal. Adopting trimmed means instead of the usual least squares estimator has been shown to be mostly affective in combating the deleterious effects of nonnormality. There are, however, practical concerns regarding trimmed means, such as the predetermined amount of symmetric trimming that is typically used. Wilcox and Keselman proposed the Modified One- Step M-estimator (MOM) which empirically determines the amount of trimming. Othman et al. found that when this estimator is used with Schrader and Hettmansperger's H statistic, rates of Type I error were well controlled even though data were nonnormal in form. In this paper, we modified the criterion for choosing the sample values for MOM by replacing the default scale estimator, MADn, with two robust scale estimators, Sn and Tn , suggested by Rousseeuw and Croux (1993). To study the robustness of the modified methods, conditions that are known to negatively affect rates of Type I error were manipulated. As well, a bootstrap method was used to generate a better approximate sampling distribution since the null distribution of MOM-H is intractable. These modified methods resulted in better Type I error control especially when data were extremely skewed.
Limiting spectral distribution of large dimensional random matrices of linear processes
Authors: Khettab Zahira
Published: December 2021

The limiting spectral distribution (LSD) of large sample radom matrices is derived under dependence conditions. We consider the matrices \(X_{N}T_{N}X_{N}^{\prime}\) , where \(X_{N}\) is a matrix (\(N \times n(N)\)) where the column vectors are modeled as linear processes, and \(T_{N}\) is a real symmetric matrix whose LSD exists. Under some conditions we show that, the LSD of \(X_{N}T_{N}X_{N}^{\prime}\) exists almost surely, as \(N \rightarrow \infty\) and \(n(N)/N \rightarrow c > 0\). Numerical simulations are also provided with the intention to study the convergence of the empirical density estimator of the spectral density of \(X_{N}T_{N}X_{N}^{\prime}\).
Statistical tools for alternative research in plant experiments
Authors: Brizzi Maurizio , Betti Lucietta
Published: December 2021

In this paper we describe the set of statistical tools applied for evaluating a series of experiments concerning the effects of homeopathic treatments in simple plant models, involving wheat seeds and seedlings and tobacco plants. The homeopathic treatment used in our experiments is arsenic trioxide, diluted in a decimal scale and dynamized \(k\) times (with \(k\) varying from 5 to 45). Since the most significant results have been achieved with As 45dH (45-th decimal potency of As2O3), we report a brief summary of these results. The statistical analysis was performed by using parametric and non parametric tests, and Poisson distribution has an essential role when dealing with germination experiments. Finally, we describe some interesting results related to the changes in variability, which seems to be a primary target of homeopathic treatment effect.
Üniversite Öğrencilerinin Finansal Okuryazarlık Düzeylerinin Tespit Edilmesi: Adnan Menderes Üniversitesi İİBF Öğrencileri Örneği
Authors: TEKİN Bilgehan , DURSUN Vedat
Published: December 2021

Bu çalışmanın amacı, İktisadi ve İdari Bilimler Fakültesi’nde öğrenim gören öğrencilerin finansal okuryazarlık bilgi, tutum ve davranış düzeylerinin incelenmesidir. Çalışmanın örneklemini Adnan Menderes Üniversitesi Nazilli İktisadi ve İdari Bilimler Fakültesi’nin farklı bölümlerinde öğrenim gören öğrenciler oluşturmuştur. Anket ile toplanan verilerin analizinde frekans analizleri, faktör analizi, bağımsız gruplar t testi, ANOVA analizi ve Ki-Kare testi kullanılmıştır. Çalışmada üç farklı finansal okuryazarlık ölçeği kullanılmıştır. Her bir ölçekle toplanan veriler kendi içerisinde analiz edilmiş, değerlendirilmiş ve yorumlanmıştır. Çalışma sonucunda finansal okuryazarlık alt ölçekleri ile cinsiyet arasında belirli düzeyde anlamlı ilişki olduğu, ebeveynlerin eğitim düzeyleri ile öğrencilerin finansal okuryazarlık düzeyleri arasında bir ilişki olmadığı, öğrenciler tarafından en fazla bilinen temel finansal kavramların sırasıyla risk-getiri oranları, hazine bonosu ve ek limit ve faiz oranları olduğu, cinsiyet ve bölüm ile finansal kavramların bilinirlik düzeyleri arasında belirli düzeylerde ilişki olduğu tespit edilmiştir.
Letramento em perspectiva: o lugar da mulher nos contos de fada
Authors: Lopes Chaves Lorena , Bicalho Ribeiro Pollyanne
Published: December 2021

Reading practices and oral and written production in elementary school" is the result of experiences undertaken regarding the teaching of Portuguese in Basic Education. The book addresses the relationship between theory and practice in order to contemplate the axes of reading, writing, orality and linguistic/semiotic analysis, in line with the assumptions defended in the Common National Curriculum Base (BNCC).
Gênero textual charge: um desafio didático
Authors: Silva Rosemeire Pedro da , Pinheiro Lima Késia Suyanne , Bastos da Escóssia Patrícia Mônica
Published: December 2021

Reading practices and oral and written production in elementary school" is the result of experiences undertaken regarding the teaching of Portuguese in Basic Education. The book addresses the relationship between theory and practice in order to contemplate the axes of reading, writing, orality and linguistic/semiotic analysis, in line with the assumptions defended in the Common National Curriculum Base (BNCC).
A biografia como deflagradora de mulheres significativas na vida de alunos do 9o ano do Ensino Fundamental: uma prática de letramento
Authors: Freitas Aguiar Juliana , Bicalho Ribeiro Pollyanne
Published: December 2021

Reading practices and oral and written production in elementary school" is the result of experiences undertaken regarding the teaching of Portuguese in Basic Education. The book addresses the relationship between theory and practice in order to contemplate the axes of reading, writing, orality and linguistic/semiotic analysis, in line with the assumptions defended in the Common National Curriculum Base (BNCC).
Mecanismos de textualização em textos injuntivos produzidos por alunos da Educação de Jovens e Adultos
Authors: Silva Cavalcanti de Menezes Ana Michele da , Pontes de Barros Leal Abniza
Published: December 2021

Reading practices and oral and written production in elementary school" is the result of experiences undertaken regarding the teaching of Portuguese in Basic Education. The book addresses the relationship between theory and practice in order to contemplate the axes of reading, writing, orality and linguistic/semiotic analysis, in line with the assumptions defended in the Common National Curriculum Base (BNCC).
O tratamento didático dos mecanismos enunciativos na aula de língua portuguesa
Authors: Matos de Amorim Aline , Lima Xavier Francisca Rebeca de
Published: December 2021

Reading practices and oral and written production in elementary school" is the result of experiences undertaken regarding the teaching of Portuguese in Basic Education. The book addresses the relationship between theory and practice in order to contemplate the axes of reading, writing, orality and linguistic/semiotic analysis, in line with the assumptions defended in the Common National Curriculum Base (BNCC).
ESTIMATION OF MASS TRANSFER OF PRINCIPLE IONS, IRON, AND METHANE DURING THE DISCHARGE OF UNDERGROUND WATER OF THE QUATERNARY AQUIFER COMPLEX TO THE SEA OF AZOV
Authors:   Institute of Water Problems of the Russian Academy of Sciences, ZUBKOV E. A. ,   Geophysical Institute - a branch of the Vladikavkaz Scientific Center of the Russian Academy of Sciences, NIKANOROV A. M. ,   Institute of Water Problems of the Russian Academy of Sciences, GAR’KUSHA D. N. ,   Institute of Geosciences, Southern Federal University, FEDOROV YU. A. ,   Institute of Geosciences, Southern Federal University, BARTSEV O. B. ,   Hydrochemical Institute
Published: December 2021

The specificity of the chemical composition of underground waters of the Quaternary aquifer complex of the Azov sea catchment basin, which dominates the flow volume, is considered. Using deterministic models, the volumes of runoff of the main ions, common iron, and methane are calculated. The predominant ones are sulphate, chloride-sulphate or sulphate-chloride, less often bicarbonate and chloride waters, usually of a sodium or calcium cationic composition. The average annual volume of underground water flow in the Quaternary complex is about 0.024 km3/year (66,300 m3/day). The average annual value of underground ion runoff is ~387,000 t/year, with 47.2% of this value being accounted for by sulfate ions. The average annual underground runoff of total iron and methane is ~0.968 t/year and ~0.037 t/year, respectively. The dominant contribution (over 98%) to the volume of underground runoff of the main ions, common iron and methane is made by their runoff from the Northern sections of the sea catchment basin, which is mainly due to the distribution of the module of underground water flow.
RESULTS OF EXPERIMENTAL STUDIES ON THE DISPERSAL OF WARM FOGS USING GAUZE ELECTROSTATIC PRECIPITATORS
Authors:   Taifun Research and Production Association, ANDREEV YU. V. , VASIL’EVA M. A. ,   Russian University of Transport, IVANOV V. N. ,   Taifun Research and Production Association, PALEY A. A. ,   Fedorov Institute of Applied Geophysics, PISANKO YU. V. ,   Fedorov Institute of Applied Geophysics, PUZOV YU. A. ,   Taifun Research and Production Association, ROMANOV N. P. ,   Taifun Research and Production Association, SAVCHENKO A. V. ,   Taifun Research and Production Association, SHVYREV YU. N. ,   Taifun Research and Production Association
Published: December 2021

The results of studies evaluating the efficiency of fog dispersion by collecting water droplets contained in the fog using the grid electrostatic precipitator are considered. The precipitator includes a corona discharge generation system that provides electric charging of fog droplets and a grounded gauze structure free for airflow. When air flows through the cells of the grounded conductive gauze, electrically charged drops are deposited on its surfaces and are separated from the wind stream. The airflow purified from drops is directed to the protected area and forces fog out of it. Data of the presented studies are based on the experiments conducted in the large aerosol chamber of the Institute of Experimental Meteorology (Taifun Research and Production Association). High efficiency of the investigated method is shown, it may be recommended for practical work to improve visibility in fog in a controlled area.
CLIMATE CHANGE ON THE TERRITORY OF RUSSIA IN THE LATE 20TH-EARLY 21ST CENTURIES
Authors:   Kazan (Volga Region) Federal University, PEREVEDENTSEV YU. P. , VASIL’EV A. A. ,   Hydrometeorological Research Center of the Russian Federation, SHERSTYUKOV B. G. ,   All-Russian Research Institute of Hydrometeorological Information-World Data Center, SHANTALINSKII K. M. ,   Kazan (Volga Region) Federal University
Published: December 2021

The spatiotemporal variability of surface air temperature and precipitation in Russia is considered using the data from 1251 stations for two periods: 1976-2019 and 2001-2019. Main attention is paid to the analysis of trends in the above characteristics, which made it possible to estimate the scale of climate warming in recent decades. The connection between the atmospheric circulation indices (NAO, AO, EAWR, SCAND) and temperature fluctuations in the European part of Russia is revealed.
ESTIMATION OF THE ICE-FREE PERIOD LENGTH FOR THE RUSSIAN ARCTIC SEAS BASED ON SATELLITE DATA FOR 2018-2020
Authors:   Arctic and Antarctic Research Institute, SMIRNOV V. G. , BYCHKOVA I. A. ,   Arctic and Antarctic Research Institute, ZAKHVATKINA N. YU. ,   Arctic and Antarctic Research Institute,   Nansen International Environmental and Remote Sensing Center, MIKHAL’TSEVA S. V. ,   Arctic and Antarctic Research Institute, PLATONOVA E. V. ,   Arctic and Antarctic Research Institute
Published: December 2021

The paper describes the experience of using routine satellite radar data to estimate the length of the ice-free period in the Northern Sea Route using a neural network method for the ice cover classification. An earlier onset of melt and a later freezing of ice in the Russian Arctic seas as compared to long-term dates is confirmed.
HYDROLOGICAL HAZARDS ON THE TERRITORY OF THE RUSSIAN FEDERATION: MULTIDIMENSIONAL ANALYSIS AND ZONING
Authors:   National Research Moscow State University of Civil Engineering, KOZLOV D. V. , SNEZHKO V. L. ,   Russian State Agrarian University - Moscow Timiryazev Agricultural Academy, LAGUTINA N. V. ,   Russian State Agrarian University - Moscow Timiryazev Agricultural Academy
Published: December 2021

The developed information and cartographic resource can be used for determining regional lists and criteria of dangerous hydrological phenomena, collecting information about the threat, possible consequences, and monitoring such phenomena. Long-term data on the number of phenomena on the territory of Russia became the statistical base. The specifics of the distribution and classification of the subjects of the Federation by types, number and frequency of occurrence of dangerous phenomena were revealed using methods of mathematical statistics and expert assessments. GIS technologies were used for mapping.
PROBLEMS OF AGRICULTURE ADAPTATION TO THE GROWING ANOMALOUS VARIABILITY OF WEATHER CONDITIONS IN THE KABARDINO-BALKARIAN REPUBLIC
Authors:   High-mountain geophysical institute, BEKKIEV M. YU. , KALOV R. O. ,   High-mountain geophysical institute
Published: December 2021

The importance of increasing the adaptive potential of agricultural production to the variability of weather conditions, the need to expand the applied use of meteorological information by agro-natural users is indicated. The analysis of the possibility of increasing the productivity of agriculture due to the prompt response to short-term meteorological forecasts is carried out. The need to develop flexible agrotechnical methods for an adequate response to local anomalous weather variability is noted. The formation of "reserve" agricultural technologies is recognized as an important way to mitigate the negative impact of unfavorable weather conditions on the efficiency of the industry.