This paper considers dimensional synthesis of a six-bar linkage with turning kinematic pairs, in the literature known as Stephenson III Six-bar linkage. The synthesis procedure started from the ...requirement that it should be a double dwell mechanism and that the coupler point, during dwell, should pass through the given points belonging to the circular arc. The coordinates of those points are not directly given; they lie on the circular arc defined by the corresponding centre of the curve and the crank angle that corresponds to the circular arc of the path during dwell. These values are obtained at the end of the optimization procedure so that in this case the precision points change their positions with the change of the position of the arc on which they lie. As this is the case with double dwell, the coupler point should describe a curve containing two circular arcs which does not have to be symmetric. A new metaheuristic algorithm, known as Cuckoo Search (CS), was used in the procedure of optimum synthesis of mechanism parameters.
► The method of dimensional synthesis of a six-bar double dwell linkage is considered. ► The circular arcs that correspond to the periods of rest are not symmetric. ► The arc's position change influences the change of the precision points positions. ► The modern metaheuristic algorithm Cuckoo Search (CS) was applied. ► The methodology of synthesis is illustrated with two examples.
The COVID-19 pandemic has brought into focus the mental health of the student population. The study aimed to analyze the psychological response to the COVID-19 outbreak in terms of perceived stress ...and its related factors among university students in south-east Serbia. The study was conducted during the increased incidence of COVID-19 in Serbia.
A total of 434 students from the public university in south-east Serbia enrolled in the study and completed the measures of socio-demographic data, the perceived stress scale (PSS-10), the Coping Strategy Indicator (CSI) and the General Health Questionnaire (GHQ-28). The data were analyzed through quantitative and qualitative methods.
Study findings suggest that the mean perceived stress score was placed to 20.43 (± 7.67). Our model showed that female gender, higher scores on anxiety/insomnia and depression subscale as well as the coping strategy avoidance predicted higher perceived stress, while higher scores on social dysfunction were related to the reduced perceived stress scores. CONCLUSION: Notwithstanding the study limitation, findings provided authentic data of stress reactions of the students in south-east Serbia during the COVID-19 outbreak. The findings confirm the need to examine students' experiences in emergencies and crises, as well as to make a plan for online stress management programs that would help alleviate stress during a global pandemic.
Individualism and collectivism are some of the most widely applied concepts in cultural and cross-cultural research. They are commonly applied by scholars who use arithmetic means or sum indexes of ...items on a scale to examine the potential similarities and differences in samples from various countries. For many reasons, cross-cultural research implicates numerous methodological and statistical pitfalls. The aim of this article is to summarize some of those pitfalls, particularly the problem of measurement non-invariance, which stems from the different understandings of questionnaire items or even different character of constructs between countries. This potential bias is reduced by latent mean comparisons performed with Multigroup Confirmatory Factor Analysis and the Measurement Invariance procedure within a Structural Equation Modeling framework. These procedures have been neglected by many researchers in the field of cross-cultural psychology, however. In this article, we compare ‘traditional’ (comparison of arithmetic means) and ‘invariant’ (latent mean comparison) approaches and provide necessary R source codes for replications of measurement invariance and latent mean comparisons within other scales. Both approaches are demonstrated with real data gathered on an Independent and Interdependent Self-Scale from 1386 participants across six countries (Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Macedonia and Albania). Our results revealed considerable differences between the ‘invariant’ and ‘traditional’ approaches, especially in post-hoc analyses. Since ‘invariant’ results can be considered less biased, this finding suggests that the currently prevalent method of comparing the arithmetic means of cross-cultural scales of individualism and collectivism can potentially cause biased results.
This article presents a comprehensive dataset and its associated data collection methodology aimed at understanding public opinion and attitudes across diverse socio-political dimensions in Czechia ...and Slovakia. The dataset covers a wide array of variables, including socio-demographic variables, media consumption patterns, scales measuring attitudes and ideology, evaluations of political statements, and reactions to political billboards. The dataset is structured into folders containing raw data, metadata, research samples, analyses, and visual stimuli used in the study. The raw data files encompass original survey responses received from participants, while the metadata provides essential details about variables, their coding, scaling, and question formulation. The survey contains data from more than 1200 Czech and Slovak participants. The samples are representative by gender, age, education level, region, and place of residence size.
Researchers utilizing this dataset have the opportunity to explore public opinion dynamics, ideological tendencies, and responses to political stimuli. The dataset's extensive and multifaceted nature offers a valuable resource for various analyses, allowing researchers to delve into factors shaping political orientations, public sentiment towards specific political narratives, and the impact of visual stimuli on political perceptions. Moreover, the dataset's inclusion of both Czechia and Slovakia provides a comparative dimension, enabling cross-country analyses and insights into potential socio-political divergences or convergences within the region. Its accessibility and comprehensiveness make it a valuable asset for a wide range of research endeavors across political science, sociology, psychology, and related disciplines.
For the development of atypical antipsychotics, the selective positive allosteric modulation of the ionotropic GABAA receptor (GABAAR) has emerged as a promising approach. In the presented research, ...two unrelated methods were used for the development of QSAR models for selective positive allosteric modulation of 1-containing GABAARs with derivatives of imidazo 1,2-a-pyridine. The development of conformation-independent QSAR models, based on descriptors derived from local molecular graph invariants and SMILES notation, was achieved with the Monte Carlo optimization method. From the vast pool of 0D, 1D, and 2D molecule descriptors, the GA-MLR method developed additional QSAR models. Various statistical methods were utilised for the determination of the developed models’ robustness, predictability, and overall quality, and according to the obtained results, all QSAR models are considered good. The molecular fragments that have a positive or negative impact on the studied activity were obtained from the studied molecules’ SMILES notations, and according to the obtained results, nine novel compounds were designed. The binding affinities to GABAAR of designed compounds were assessed with the application of molecular docking studies and the obtained results showed a high correlation with results obtained from QSAR modeling. To assess all designed molecules’ “drug-likeness”, their physicochemical descriptors were computed and utilised for the prediction of medicinal chemistry friendliness, pharmacokinetic properties, ADME parameters, and druglike nature.
The area that causes great attention of economic science is the issue of growth and development. The impact of human resources on economic growth is of great importance. Human capital is the driver ...of the economic growth of any national economy, on the other hand, the state is the driver of education of its population. An important driver of development is education, i.e. investing in the education system, which further drives other macroeconomic variables. Both theory and practice are increasingly dealing with the issue of human capital, as important components and factors of the overall economic development of the national economy. Investments in education result in an increase in economic growth, this increase allows for greater investment in future education. Long-term economic growth determines the standard of living, which directly affects human development. The Human Development Index sublimates several parameters in itself and at the same time shows correlations between the economy, quality of life, and level of education in the country. The paper aims to point out the importance of human capital in economic science and practice through the paradigm of the concept of human development, following the trends of HDI in the Republic of Serbia and the surrounding countries.
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