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31The relationship between life satisfaction and alienation level of disabled athletes (Kayseri Case)
Ozkatar Kaya e.1abde, Pekel A.2ABCD 1Erciyes University, Faculty of Sports Sciences, Kayseri, Turkey 2Istanbul Gelisim University, College of Physical Education and Sports, Istanbul, Turkey
Authors' Contribution: A - Study design; B - Data collection; C - Statistical analysis; D - Manuscript Preparation;
E - Funds Collection.
Abstract
Purpose: The aim of this study is to investigate the relationship between life satisfaction and alienation level of disabled athletes living in Kayseri.
Material: The population of the study consists of 421 disabled athletes engaged in sports. The sample consisted of 109 disabled athletes identified by simple random sampling method. The study was performed by scanning method and the data was collected by survey method. Demographic information form consists of 5 questions, «Life Satisfaction Scale» which was developed by Diener et.al. and translated into Turkish by Koker, of which reliability and validity study had been conducted and the «Alienation Scale» developed by Dean and adopted into Turkish by Kinik were applied. The obtained data were recorded in the SPSS 23 package program. Mann Whitney U test was used for comparison of binary groups and Kruskal Wallis test was used for multiple comparisons. Spearman Correlation test was applied to determine the relationship between life satisfaction and alienation level sub-dimensions.
Results: It has been determined that there is a difference between life satisfaction and alienation level sub-dimension
scores of disabled athletes according to the gender and marital status, that there is a difference according to life satisfaction level score and ages of 18-23, 24-29 and 18-23 and 30 and above in terms of alienation level and irregularity sub dimensions; and ages of 18-23, 24-29 and 18-23 and 30 and above in terms of social isolation sub dimension and that there is a statistically significant difference between their life satisfaction level score according to education status and alienation level sub dimension. It has been determined that there is a negative and medium sized relation between the level of alienation and life satisfaction, weakness (r = -.491, p =.050) and the irregularity (r = -.619, p =.050) sub-dimension, and that there is a positive relation between life satisfaction and social isolation sub dimension (r=.795, p= .050).
Conclusions: A medium level negative relation was determined between the level of life satisfaction and alienation with gender, age, marital status and educational status and between the level of alienation with life satisfaction and weakness and irregularity sub dimensions; and a high positive relation was determined with the social isolation sub dimension.
Keywords: disabled individuals, alienation, life satisfaction, athletes, social.
Introduction
It is known that disabled individuals in Turkey have intense problems in terms of integration with the society. Problems in many areas of life make it difficult for disabled individuals to live in a functional unity with the society they are a part of. Individuals who constantly struggle with problems and who cannot produce meaningful solutions will feel unhappy. This means a lower quality of life, eliminating the self-realization, a fundamental human right [1]. Quality of life indicates the result of comparing the expectations of individual with the real status, depending on life satisfaction. Because life satisfaction determines the level of individual reaching the goals he/she has set or reaching to happiness. Any increase in reaching the individual goals will increase the life satisfaction [2]. In other words, it is related how much a person likes his/her own life [3]. Improving the quality of life of the disabled individuals will be possible through integrating disabled individuals within the society at the highest level and this is also a social responsibility [4].
But today, the rapid change brought with
© Ozkatar Kaya E., Pekel A., 2019 doi:10.15561/18189172.2019.0106
industrialization and technological developments causes the individual to suffer from loneliness and alienation. On the other hand, individuals are concerned about fulfilling their responsibilities in daily life, building relationships with others and maintaining a healthy life. The emergence of the phenomenon of alienation increases rapidly as these changes and developments occur [5]. In addition, alienation can be directed towards one's own self or to the parts of the self as well as towards others [6]. Considering the individuals with disabilities, it has been suggested that alienation is a disease that occurs due to social conditions and emotional personality. There are five different dimensions of alienation regarding an individual's self-perception and behavior. These are: Weakness, Futility, Irregularity, Alienation to Society and Self Alienation [7].
Finally, the restrictive, stigmatizing, discriminatory and hence obstructive attitudes of the society towards disabled individuals set up the environment where individuals with disabilities are isolated from society. In recent years, the integrative approach of social model between the disabled individuals and society has been increasingly accepted. It is stated that individuals with disabilities have a great need for such an approach [8].
^■^2019
Hypothesis: There is a relationship between the level of life satisfaction and the level of alienation of disabled individuals engaged in sports. According to some demographic characteristics of disabled individuals engaged in sports, there is a difference between the levels of life satisfaction and alienation.
Purpose: The purpose of this study is to investigate the relationship between life satisfaction and alienation level of disabled athletes living in Kayseri.
Material and Method
Participants
Forming Voluntary Groups:
For the purpose of the study, the population of the study was composed of disabled (physical, auditory and visually impaired) individuals (n = 421) and the sample consists of voluntary disabled athletes who were selected by simple random method (n= 109). After the participants were informed about the study, participation in the study was carried out voluntarily.
Measurements and Procedures.
The study was performed by scanning method and the data was collected by survey method. Personal information form (gender, age, marital status, education status), life satisfaction and alienation scale were applied to the participants.
In order to measure the level of life satisfaction of the participants, a 5-item life satisfaction scale was used, which was developed by Diener et al. [9] and translated into Turkish by Koker [10] with a validity and reliability value of 0.90. The highest score that could be obtained from the scale is 35, whereas the lowest score is 5. The reliability of life satisfaction scale is 0.90. It is stated that life satisfaction increases as the score obtained from the scale does [10]. The scale questions consist of seven scales in the Likert Type Scale; such as "I Completely Agree", "I Strongly Agree", "I Agree", "I Somewhat Agree", "Neutral", "I Disagree" and "I Totally Disagree". In order to measure the alienation level of participants, the "Alienation Scale", which was developed by Dean [11] and adapted to Turkish by Kinik [5] with validity and reliability value of 0.82 was used. Alienation scale consists of 24 items and 3 sub dimensions. The Weakness dimension of the Alienation process consists of items 2, 6, 9, 13, 15, 18, 20, 21 and 23; the Irregularity dimension
Table 1. Socio-Demographical Characteristics of Participants
of the Alienation process consists of items 4, 7, 10, 12, 16 and 19; and the Social Isolation dimension of the Alienation process consists of items 1, 3, 5, 8, 11, 14, 17, 22 and 24. There are five statements in each of the 24 items in the Alienation Survey. The items in the scale are in the form of "5-Likert Type Scale" with 1 as "Never", 2 as "Rarely", 3 as "Sometimes", 4 as "Mostly" and 5 as "Always".
Statistical Analysis
The data obtained were recorded on computer with package program of IBM SPSS 23.0. Personal information, inventory averages and factor scores were provided by determining the frequency (f) and percentage (%) values of the participants. The parametric and non-parametric distribution of the were analyzed by focusing on parametric and non-parametric distribution curves and skewness-kurtosis values. Data have non-parametric distribution. Mann Whitney U test was used for comparison of binary groups and Kruskal Wallis test was used for multiple comparisons. Spearman Correlation test was used to determine the relationship between the sub-dimensions of Life satisfaction and Aleination level.
Results
When Table 1 is examined, it is determined that among the disabled individuals; 54.1 % are male and 45.9 % are female, 28.4 % are between the ages 18-23, 21.1 between the ages 24 and 29 and 50.5 % are 30 years or above; 54.1 % are single and 45.9 % are single and 26.6 % have primary school education level and 73.4 % have secondary school education level.
Table 2 indicates the comparison of life satisfaction scores and alienation level sub-dimension scores according to the gender of the participants. A statistically significant difference was found between the participants' life satisfaction level scores and alienation level scores (p <0.05).
Table 3 indicates the comparison of life satisfaction scores and alienation level sub-dimension scores according to the age of the participants. According to the age group of the participants, there was a statistically significant difference between the ages of 18-23 and 24-29, and between the ages 18-23 and 30 (p <0.05). Statistically significant difference was determined regarding the level of alienation of participants under the sub dimension of
Characteristic Variables Frequency Percentage
Gender Male 59 54.1
Female 50 45.9
18-23 31 28.4
Age 24-29 23 21.1
30 and above 55 50.5
Married 59 54.1
Marital Status
Single 50 45.9
Educational Status Primary School 29 26.6
Secondary School 80 73.4
irregularity for the ages 18-23 and 24-29 and 27-29 and above 30, and under the sub dimension of social isolation for the ages 18-23 and 24-29 and 27-29 and above 30 (p<0.05).
Table 4 indicates the comparison of life satisfaction scores and alienation level sub-dimension scores according to the marital status of the participants. A statistically significant difference was found between the participants'
Table 2. Assessment of Participants' Life Satisfaction and Alienation Level and Perceptions According to Their Gender
Characteristic Gender n median min max Z P
Male 59 14 10 20
Life Satisfaction -8.014 .000
Female 50 30 27 34
Male 59 24 14 33
Weakness -1.442 .000
Female 50 22 22 24
Male 59 18 7 19
Irregularity Female 50 14 15 15 -6.104 .001
Male 59 26 15 28
Social Isolation Female -7.589 .000
50 29 30 31
Note: n 109; Life Satisfaction: (Z=8.014; P= .000); Weakness: (Z= -1.442; P= .000); Irregularity: (Z=-6.104; P= .001); Social Isolation: (Z=-7.589; P= .000); P< 0.050
Table 3. Assessment of Participants' Life Satisfaction and Alienation Level and Perceptions According to Their Age
Characteristic Age n median min max X2 P Difference
18-231 31 31 19 33
24-292 1-2
Life Satisfaction 23 17 12 28 34.11 .000
1-3
30 and above 3 55 19 12 34
18-231 31 24 24 35
Weakness 24-292 23 24 14 35 4.59 .101 -
30 and above 3 55 24 14 35
18-231 31 15 15 20
1-2
Irregularity 24-292 23 16 7 20 17.09 .000 1-3
30 and above 3 55 16 7 20
18-231 31 31 25 31
24-292 1-2
Social Isolation 23 26 16 31 40.89 .000
1-3
30 and above 3 55 26 16 31
Note: n=1DS; Р<.О5О
Table 4. Assessment of Participants' Life Satisfaction and Alienation Level and Perceptions According to Their Marital Status
Characteristic Marital Status n median min max Z P
Married 59 16 12 22
Life Satisfaction -9.014 .000
Single 50 31 27 34
Married 59 26 14 35
Weakness -3.743 .000
Single 50 24 24 24
Married 59 19 7 20
Irregularity -6.608 .000
Single 50 15 15 15
Married 59 26 16 29
Social Isolation Single -9.509 .000
50 31 31 31
Note: n=109; Life Satisfaction (Z: -9.014; P= .000); Weakness: (Z= -3.743; P= .000); Irregularity: (Z= -6.608; P= .000); Social Isolation: (Z= -9.509; P= .000); P<.001
2019
Table 5. Assessment of Participants' Life Satisfaction and Alienation Level and Perceptions According to Their Educational Status
Characteristic Educational Status n median min max Z P
Primary School 29 16 15 19
Life Satisfaction Secondary School 80 30 12 34 -6.123 .000
Primary School 29 35 14 35
Weakness Secondary School 80 24 24 26 -3.537 .000
Primary School 29 20 7 20
Irregularity Secondary School 80 15 15 19 -3.198 .001
Primary School 29 25 16 25
Social Isolation Secondary School 80 31 26 31 -8.432 .000
Note: n= 109; Life Satisfaction: (Z= -6.123; P= .000); Weakness: (Z= -3.537; P= .000); Irregularity: (Z= -3.198; P= .001); Social Isolation: (Z=-9.509; P= .000); P<.050
Table 6. Relation Between the Life Satisfaction and Alienation Level of Participants
Characteristic
Spearman Correlation
Life Satisfaction
Weakness
Irregularity
Social Isolation
r 1
p
n 109
r -.491 1
p .000
n 109 109
r -.619 .904 1
p .000 .000
n 109 109
r .795 -.247 -.458
p .000 .010 .000
n 109 109 109
1
2
3
4
1
Note: Life Satisfaction (1)- (r=1); Weakness (2) - (r=-.409; p=.000); Irregularity (3) - (r= -.619; p=.000); Social Isolation (4) - (r= .795; p= .000); P<.001
life satisfaction level scores, their alienation level scores and perception sub dimension scores (p <0.05).
Table 5 indicates the comparison of life satisfaction scores and alienation level sub-dimension scores according to the educational status of the participants. A statistically significant difference was found between the participants' life satisfaction level scores and alienation level scores according to their educational status (p <0.05).
As it can be seen in Table 6, it has been determined that there is a negative and medium sized relation between the level of alienation and life satisfaction, weakness (r = -, 491, p =, 050) and the irregularity (r = -, 619, p =, 050) sub-dimension, and that there is a positive relation between life satisfaction and social isolation sub dimension (r=,795, p= ,050).
Discussion
Life satisfaction is described as the individual's feeling of well-being from different perspectives such as happiness and spirits and as the dominance of positive emotion over negative ones as a result of person's good feelings in social and physical terms [12]. Alienation is a psychological state which appears as a result of individual and social processes. Therefore, the role of the individual in society and acceptance of society are important in personal self-realization [13]. The number of people with disabilities is increasing in Turkey and sport is considered as an important factor in adapting the disabled individuals to the society. Regarding the disabled individuals within the scope of this study, the importance of sport for their reintegration into the society and their life satisfaction and
alienation levels were examined to find out whether there were any differences or not.
There was a statistically significant difference between the satisfaction level score and alienation level subdimension scores of participants according to their gender. According to this, life satisfaction score of women with disabilities is higher than that of men with disabilities. Again, it is seen that social isolation level of disabled women as a sub dimension of alienation is higher than the disabled male individuals. In this case, it can be said that life satisfaction of disabled individuals participating in the study is affected by their gender. When the literature is examined, studies indicate that self-confidence and life satisfaction levels of the physically disabled athletes differ according to gender variable. It is reported that female athletes with physical disabilities have a higher self-confidence and life satisfaction when compared with the male athletes [14]. Culture, type of sports, self-esteem and activity [15], ability to manage the situation, and to have a feeling of significance with themselves and their environment are reported as contributing to life satisfaction [16].
When the comparison of life satisfaction and alienation level sub-dimension scores according to the age of the participants is examined; a significant difference was determined regarding the level of alienation of participants under the sub dimension of irregularity for the ages 18-23 and 24-29 and 27-29 and above 30, and under the sub dimension of social isolation for the ages 18-23 and 2429 and 27-29 and above 30. The level of perception of life, level of alienation and sub-dimensions of perception of alienation and social isolation were high. In this case, although the sports activities of disabled individuals increase their life satisfaction levels, it is understood that social and cultural characteristics, self-realization level and ages also increase the alienation level of the disabled individuals. No studies could be found in the literature that support our research.
According to the marital status of the participants, it was found that there was a statistically significant difference between the level of life satisfaction and alienation level sub-dimension scores. It is seen that the single disabled individuals have higher level of life satisfaction levels than the married ones.
It is seen that weakness and irregularity levels, two sub dimensions of alienation, are higher among the married disabled athletes than the single ones; and the social isolation levels of singles are higher than the married ones. The perspective of individuals to the dimensions of alienation according to marital status differ. In general, if we consider marriage as a situation that enables the development and happiness of the individual, the high levels of life satisfaction rates and social isolation among singles in this study reveals different results. §ahin and Akpinar [17] reported that life satisfaction of married persons with disabilities was higher than that of singles. This study is not in parallel with our findings.
A statistically significant difference was found between life satisfaction level and alienation level sub-
dimension scores according to the education level of the participants.
According to the level of education, life satisfaction scores of secondary school graduates are higher. When the sub-dimensions of alienation were examined, it was found that the scores of primary school graduates in weakness and irregularity were higher and the scores of secondary school graduates were higher in social isolation dimension. When the literature is examined, Purutguoglu and Aksel [18] reported that the level of education affects the behavior and lifestyle of women with disabilities. Considering that the educated individual is better acquainted with self, it is stated that life satisfaction will also increase [18]. There are studies in the literature which state that there is a relation between the variables of education level and occupation status and the life satisfaction.
It has been found that there is a high positive relationship between life satisfaction of disabled individuals and alienation level's sub dimensions of weakness and irregularity in a negative level, and a high positive relation between life satisfaction and social isolation sub-dimension.
The conclusion of the fact that disabled individuals involved in sports have a certain level of life satisfaction, but also feel as isolated from society is an unexpected result. We can explain this with psychological and physical circumstances of the individual. Individuals may have been satisfied with life with the support of sports in their inner world by isolating themselves from today's society. On the other hand, individuals with disabilities may feel isolated from the society due to their physical and physiological deficiencies. We define weakness as the person's inability to influence the society he / she lives in, and to think that he / she does not have anything to change the result. In addition, irregularity is defined as the individual's adoption of unacceptable behavior by the society in order to achieve the achievement goals determined by social norms [21]. According to these explanations, it can be seen that there is a negative relationship between the life satisfaction of disabled people and weakness and irregularity.
Conclusions
As a result, it is determined that the level of life satisfaction and alienation is related to gender, age, marital status and educational status; and that there is a medium level negative relation between the sub dimensions of weakness and irregularity; and a high level of positive relation between the life satisfaction and alienation level and social isolation sub dimension.
It is considered that the type of sports disabled individuals does, their social and cultural environment, self-esteem and physical activity level have positive contribution to their life satisfaction. In addition, when we look at the average of the variables such as gender, marital status, age, education level and occupation of the disabled individuals; we can say that sport has increased the life satisfaction of the individual. At the same time, it
is considered that the fear that the individuals' attitudes and behaviors will not be accepted within the society and that they will not have equal opportunities and rights with other individuals also increase the level of alienation.
The study group consists of physical, auditory and visually impaired people. Therefore, there are differences in life satisfaction levels and alienation levels. A separate study can be conducted done for each disabled group. Thus, different disability groups can be evaluated separately and then compared with other disabled groups. On the other hand, the study consists of disabled individuals living in Kayseri only, which is a limitation of our study area. The
study can also be extended to a wider geography and thus the research area can be expanded. Despite the fact that people with disabilities have provided life satisfaction, physical and physiological insufficiency compared to other individuals in society may have caused social alienation. For this reason, training and counseling should be done within the scope of rehabilitation program which may be psychological support for disabled people.
Conflict of Interests
No conflicts of interest have been stated by the authors.
References
1. Karata§ K. Engellilerin toplumla butunle^me sorunlari [Problems of integration of people with disabilities into society]. Ufkun Otesi Bilim Dergisi. 2002; 2 (2): 43-55. (In Turkish)
2. Ozgen F. Beden egitimi ve spor yuksekokulu ogrencilerinin yaqam doyumu duzeylerinin incelenmesi [Examination of life satisfaction levels of physical education and sports college students]. [PhD thesis]. Qanakkale Onsekiz Mart University; 2012. (In Turkish)
3. Ozdevecioglu M, Akta§ A. Kariyer bagliligi meslek baglilik ve orgutsel bagliligin ya§am tatmini uzerindeki etkisi i§ -aile fati^masmin rolu [The effects of career commitment, occupational commitment and organizational commitment on life satisfaction: the role of work-family conflict Erciyes University IIBF. Dergisi. 2007; 28:1-19. (In Turkish)
4. Milli Egitim Bakanligi. Aile ve Tuketici Hizmetleri, Engelli Bireylerde Toplumsal Uyum [Family and consumer services, social compliance in people with disabilities]. Ankara; 2011. (In Turkish)
5. Kinik Fayda §ehkar F. Ogretmenlerin yabancilaqma algilari [Teachers' perceptions of alienation]. [Master thesis]. Yildiz Technical University; 2010. (In Turkish)
6. §im§ek H, Balay R, §im§ek AS. ilkogretim sinif ogretmenlerinde mesleki yabancilaqma [Alienation from work of elementary school teachers]. Egitim Bilimleri AraqtirmaDergisi. 2012; 2(1):54-55. (In Turkish)
7. Ofluoglu G. Turkiye Taqkomuru Kurumu Kozlu Iqletme muessesesinde yabancilaqmanin boyutlari uzerinde etkili olan nedenlerin araqtirilmasi [Investigation of effects on the sizes of alienation of Kozlu dimensions Turkish Coal Association Business]. Zonguldak Karaelmas Universty i.i.B.F. iqletme Bolumu Kamu-iq. 2008; 9(4):5-8. (In Turkish)
8. Arikan Q. Sosyal model ferfevesinde ozurluluge yaklaqim [Approach to disability within the framework of social model]. Ufkun Otesi Bilim Dergisi. 2002; 2(1):120-125. (In Turkish)
9. Diener ED, Emmons R.A, Larsen R.J, Griffin S. The satisfaction with life scale. Journal of Personality Assessment. 1985; 49 (1): 71- 75. https://doi.org/10.1207/s15327752jpa4901_13
10.Koker S. Normal ve sorunlu ergenlerin yaqam doyumu duzeyinin karqilaqtirilmasi [Comparison of life satisfaction level of normal and problematic adolescents]. [master thesis]. Ankara Universty; 1991. (In Turkish)
11.Dean DG. Alienation: its meaning and measurement.
American Sociological Review. 1961; (26)5: 753- 758. https://doi.org/10.2307/2090204
12.Özgen F. Q.O.M.Ü Beden Egitimi ve Spor Yüksekokulu ögrencilerinin yaqam doyumu düzeylerinin incelenmesi. [Examination of the life satisfaction levels of the students of the School of Physical Education and Sports]. [Graduation thesis]. 2012. (In Turkish)
13. Akyildiz H. Bireysel ve toplumsal boyutlanyla yabancilaqma [Individual and social dimensions of alienation]. Süleyman Demirel Universty iktisadi ve idari Bilimler Fakültesi Dergisi. 1998; 3: 163-176. (In Turkish)
14.Duman S, Baqtug G, Taqgin Ö, Akandere M. Bedensel engelli sporcularda kendine güven duygusu ile yaqam doyumu düzeyi arasindaki iliqkinin incelenmesi [The evalation of the relation between self-confidence and level of life satisfaction of the physically handicapped athletes]. Uluslararasi insan Bilimleri Dergisi. 2011; 8(1): 1365-1373. (In Turkish)
15.Cheng H, Furnham A. Personality self-esteem and demographic predictions of happiness and depression. personality and individual differences. Page IFC. 2003; 34(6): 921-942.
16.Compton W.C. Meaningfulness as a mediator of subjective wellbeing. Psychological Reports, 2000; 87: 156- 60. https://doi.org/10.2466/pr0.2000.87.L156
17.§ahin G, Akpinar R.B. Ortopedik engelli bireylerin öfke ifade bilimleri, benlik saygilari ve yaqam doyumlari [Anger and Anger Expression Styles, Self-Esteem and Life Satisfaction of Individuals with Orthopedic Handicap]. Anadolu Hemqirelik ve SaglikBilimleri Dergisi. 2016;19(3): 196-209. (In Turkish)
18.Purutfuoglu E, Aksel C. Engelli kadinlarin beden imaji algisi ile yaqam doyumunun belirlenmesi [The determination of body image and life satisfaction of disabled women]. Uluslararasi Sosyal Araqtirmalar Dergisi. 2017;10 (50): 428-440. (In Turkish)
19.Barisin A, Benjak T, Vuletic G. Health- related quality of life of women with disabilities in relation to their employment status. Croatian Medical Journal. 2011; 52(4):550- 556. https://doi.org/10.3325/cmj.2011.52.550
20.AddabboTindara, Sarti Elena, Sciulli Dario. Disability and Life Satisfaction in Italy, Working Paper Series; 2014.
21.Qilesiz E. Iq gören yabancilaqma ile örgütsel baglilik arasindaki iliqki: ankara'daki beq yildizli oteller üzerine bir uygulama [The relationship between alienation and organizational commitment: an application on five-star hotels in Ankara]. [Master thesis]. Atatürk Universty; 2014. (In Turkish)
Information about the authors:
Ozkatar Kaya E.; http://orcid.org/0000-0002-6349-8761; [email protected]; Erciyes University, Faculty of Sports Sciences; Talas/Kayseri, 38039, Turkey.
Pekel A.; (Corresponding author); http://orcid.org/0000-0003-0238-1081; [email protected].; Physical and Sport College, Istanbul Geli?im University; Cihangir Mahallesi §ehit Jandarma Komando Er Hakan Oner Sk. No:1 Avcilar/istanbul, Turkey.
Cite this article as:
Ozkatar Kaya E, Pekel A. The relationship between life satisfaction and alienation level of disabled athletes (Kayseri Case). Pedagogics, psychology, medical-biological problems of physical training and sports, 2019;23(1):36-42. https://doi.org/10.15561/18189172.2019.0106
The electronic version of this article is the complete one and can be found online at: https://www.sportpedagogy.org.ua/index.php/PPS/issue/archive
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Received: 08.12.2018
Accepted: 15.01.2019; Published: 27.02.2019
