•Impact of COVID-19 on work-related attitudes and turnover intentions of employees in hospitality industry.•Job insecurity and changes in the organization were predictors of all outcomes, in a ...negative direction.•Risk taking behavior acted as predictor of job satisfaction, in a negative direction.•Age and marital status had significant impact on job motivation and turnover intentions.
A crisis caused by COVID-19 pandemic affected the whole world leaving long-lasting effects on almost every aspect of human lives. The aim of this study was to test how different effects of COVID-19, expressed through job insecurity, employees' health complaints occurred during isolation, risk-taking behavior at workplace and changes in the organization, may impact work-related attitudes (job motivation and job satisfaction) and turnover intentions of the employees in hospitality industry. Based on the data collected from 624 hospitality workers from Serbia, the results indicated that job insecurity and changes in the organization were predictors of all outcomes, in a negative direction, while risk-taking behavior acted as a predictor of job satisfaction only, also in a negative direction. The significance of demographic characteristics, as control variables, showed that age and marital status had significant impact on job motivation and turnover intentions. The theoretical and practical implications were discussed.
The pyrazolone class comprises a variety of hybrid compounds displaying diverse biological actions. Although studied for decades, these compounds are still of interest due to their facile chemical ...transformations. In our previous work, we presented the synthetic route of functionalised pyrazolone derivatives. The presence of pyrazolone structural motif in many drugs, such as edaravone, prompted us to investigate the antioxidant features of the selected compounds. In this paper, we provide an extensive
and
description of the antioxidant properties of selected pyrazolone analogues. The obtained
results revealed their great antiradical potency against the DPPH radical (IC
values in the 2.6-7.8 μM range), where the best results were obtained for analogues bearing a catechol moiety. Density functional theory (DFT) was used to assess their antioxidant capacity from the thermodynamic aspect. Here, good agreement with
results was achieved. DFT was employed for the prediction of the most preferable radical scavenging pathway, also. In polar solvents, the SPLET mechanism is a favourable scavenging route, whereas in nonpolar solvents the HAT is slightly predominant. Furthermore, antioxidant mechanisms were studied in the presence of relevant reactive oxygen species. The obtained values of the reaction enthalpies with the selected radicals revealed that HAT is slightly prevailing in polar solvents, while the SPLET mechanism is dominant in nonpolar solvents. Regarding the well-known antioxidant features of the drug edaravone, these findings represent valuable data for this pyrazolone class and could be used as the basis for further investigations.
The antioxidative capacity and structure–activity relationships of ten Schiff bases were investigated experimentally and theoretically. All compounds contain the aniline moiety, while the aldehyde ...part is either salicylaldehyde or vanillin. The DPPH assay was used to test the potential antioxidative activity of these compounds, and DFT study was used to investigate their electronic structures and provide insight into their structure–activity relationships. The effect of the position of the hydroxy, as well other groups present, on the antioxidative activity was examined. The possible radical scavenging mechanism was determined in polar (water and methanol), and nonpolar (benzene) solvents. Based on the experimental and computational results, compounds 7 and 8 exhibit the highest radical scavenging properties.
Currently, there is a global pandemic of COVID-19. To assess its prevalence, it is necessary to have adequate models that allow real-time modeling of the impact of various quarantine measures by the ...state. The SIR model, which is implemented using a multi-agent system based on mobile cellular automata, was improved. The paper suggests ways to improve the rules of the interaction and behavior of agents. Methods of comparing the parameters of the SIR model with real geographical, social and medical indicators have been developed. That allows the modeling of the spatial distribution of COVID-19 as a single location and as the whole country consisting of individual regions that interact with each other by transport, taking into account factors such as public transport, supermarkets, schools, universities, gyms, churches, parks. The developed model also allows us to assess the impact of quarantine, restrictions on transport connections between regions, to take into account such factors as the incubation period, the mask regime, maintaining a safe distance between people, and so on. A number of experiments were conducted in the work, which made it possible to assess both the impact of individual measures to stop the pandemic and their comprehensive application. A method of comparing computer-time and dynamic parameters of the model with real data is proposed, which allowed assessing the effectiveness of the government in stopping the pandemic in the Chernivtsi region, Ukraine. A simulation of the pandemic spread in countries such as Slovakia, Turkey and Serbia was also conducted. The calculations showed the high-accuracy matching of the forecast model with real data.
We introduce the time-dependent density matrix renormalization group (tDMRG) as a solution to a long-standing problem in spintronics—how to describe spin-transfer torque (STT) between flowing spins ...of conduction electrons and localized spins within a magnetic material by treating the dynamics of both spin species fully quantum mechanically. In contrast to conventional Slonczewski-Berger STT, where the localized spins are viewed as classical vectors obeying the Landau-Lifshitz-Gilbert equation and where their STT-driven dynamics is initiated only when the spin polarization of flowing electrons and localized spins are noncollinear, quantum STT can occur when these vectors are collinear but antiparallel. Using tDMRG, we simulate the time evolution of a many-body quantum state of electrons and localized spins, where the former are injected as a spin-polarized current pulse while the latter comprise a quantum Heisenberg ferromagnetic metallic (FM) spin-12XXZchain initially in the ground state with spin polarization antiparallel to that of injected electrons. The quantum STT reverses the direction of localized spins, but without rotation from the initial orientation, when the number of injected electrons exceeds the number of localized spins. Such nonclassical reversal, which is absent from Landau-Lifshitz-Gilbert dynamics, is strikingly inhomogeneous across the FM chain, and it can be accompanied by reduction of the magnetization associated with localized spins, even to zero at specific locations. This feature arises because quantum STT generates a highly entangled nonequilibrium many-body state of all flowing and localized spins, despite starting from the initially unentangled ground state of a mundane FM. Furthermore, the mutual information between localized spins at the FM edges remains nonzero even at infinite separation as the signature of dynamical buildup of long-range entanglement. The growth in time of entanglement entropy differentiates between the quantum and conventional (i.e., noncollinear) setups for STT, reaching a much larger asymptotic value in the former case.
As one of the first European cases of the introduction of COVID-19 certificates, the Serbian Government initiated the measure of limited working hours of restaurants for unvaccinated visitors. Due to ...such actions and frequent bans on working during the pandemic, many restaurants in Serbia had to lay off workers or close. At the end of October 2021, the certificate for entering restaurants and all catering facilities for all the visitors became mandatory. It is interesting to note that earlier findings suggested that some personality characteristics determine the specific behaviors during the pandemic, but there is still a small number of results related to restaurants’ visitors. This study aimed to investigate the predictive strength of the Big Five Factors (BFF) to attitudes toward visits to restaurants in Serbia during the pandemic, depending on the attitudes toward accepting COVID-19 certificates. A survey was conducted on a total sample of 953 visitors of restaurants in three major cities in Serbia. The results of hierarchical regression analysis showed that Openness and Extraversion positively predict attitudes toward visits to facilities during a pandemic, while Conscientiousness and Neuroticism were negative predictors. However, in the second step of hierarchical regression analysis, attitudes toward a COVID-19 certificate as a mediator variable significantly reduced the negative effect of Neuroticism on the attitudes toward visits. It seems that, by obtaining the certificate, the fear of unsafe stays in restaurants can be reduced, and that making decisions about (no) visiting restaurants during the pandemic does not necessarily have to be compromised by emotional lability.
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