SummaryLoneliness is the distressing feeling associated with the perceived absence of satisfying social relationships [1]. Loneliness is increasingly prevalent in modern societies [2, 3] and has detrimental effects on health and happiness [4, 5]. Although situational threats to social relationships can transiently induce the emotion of loneliness, susceptibility to loneliness is a stable trait that varies across individuals [6–8] and is to some extent heritable [9–11]. However, little is known about the neural processes associated with loneliness (but see [12–14]). Here, we hypothesized that individual differences in loneliness might be reflected in the structure of the brain regions associated with social processes [15]. To test this hypothesis, we used voxel-based morphometry and showed that lonely individuals have less gray matter in the left posterior superior temporal sulcus (pSTS)—an area implicated in basic social perception. As this finding predicted, we further confirmed that loneliness was associated with difficulty in processing social cues. Although other sociopsychological factors such as social network size, anxiety, and empathy independently contributed to loneliness, only basic social perception skills mediated the association between the pSTS volume and loneliness. Taken together, our results suggest that basic social perceptual abilities play an important role in shaping an individual’s loneliness.

The smart sustainable city (SSC) is a concept created in response to problems and challenges arising from rapid urbanization. This is a relatively new term that is developing dynamically, which is confirmed by the growing number of publications over recent years. For this reason, this article presented an up-to-date comprehensive bibliometric analysis to describe and assess the scientific landscape of smart and sustainable cities literature. The analysis was based on two bibliographic sources—the Web of Science Core Collection and the Scopus database. It covers publications on the SSC, as well as documents describing the smart city (SC) and the sustainable city (SuC) concepts separately. VOSviewer and Biblioshiny were selected as software tools for the bibliometric analysis. Based on the descriptive bibliometric analysis, quantity and quality indicators were determined separately for the SC, SuC, and SSC concepts, while the network analysis mapped and covered the level of multi-faceted scientific cooperation in the field of the SSC research. The analysis results were intended to familiarize scholars and practitioners with the most prolific authors, sources, institutions, and countries in the analyzed scientific field, to identify the most influential research channels and impact from authors, sources, countries, and research topics, to determine major clusters of the SSC research and also to provide valuable information for further investigation.

Synesthesia is a rare condition in which one property of a stimulus (e.g., shape) triggers a secondary percept (e.g., color) not typically associated with the first. Work on synesthesia has predominantly focused on confirming the authenticity of synesthetic experience, but much less research has been conducted to examine the extent to which synesthesia is linked to broader perceptual differences. In the research reported here, we examined whether synesthesia is associated with differences in color and motion processing by comparing these abilities in synesthetes who experience color as their evoked sensation with nonsynesthetic participants. We show that synesthesia for color is linked to facilitated color sensitivity but decreased motion sensitivity. These findings are discussed in relation to the neurocognitive mechanisms of synesthesia and interactions between color and motion processing in typical adults.

The achievement of climate neutrality and eco-economic decoupling requires explicit measures to reduce greenhouse gases (GHG) emissions and to implement circular economy (CE) principles in practice. The energy sector is of particular importance in meeting these challenges because it exerts a substantial environmental impact. Therefore, it is extremely important to determine how essential GHG and CE issues are for companies operating in the energy sector. This can be reflected in corporate strategies, but it can also be disclosed to the public in sustainability reports. For this reason, this article presents a comprehensive analysis of sustainability reports based on the latest GRI Standards published by companies representing the energy sector in the European Union to determine the existence, quality, and specificity of reporting GHG and CE issues. The research results demonstrate that sustainability reports from the energy sector companies tend to focus more on GHG issues. They rarely point to actions related to CE, including actions enabling a reduction in GHG emissions, as those with high priority. In addition, declarations from the analyzed companies regarding intentions related to GHG and CE issues at the strategic level find a rather poor reflection in the description of specific actions in this area or in demonstrating appropriate indicators at the operational level. Considering the indicators included in the reports, the analyzed companies insufficiently describe the methods they use to gather, compile, and analyze information on the effectiveness of actions taken to address GHG and CE issues. As for the identification of potential determinants of the quality of reporting GHG and CE issues, the research results indicate that it is mostly influenced by external assurance and the report option. Sustainability reports submitted for external assurance and reports with the comprehensive option are significantly more developed than other types of reports. However, the clarity of reports with the core option is higher compared to the comprehensive group. In addition, it was indicated that the clarity of stand-alone reports is higher compared to other types of reports.

The circular economy (CE) concept is now gaining increasing attention and it is being widely explored as a promising path to sustainable development. CE implementation requires extensive activities needed for the transition from the linear to the circular model and suitable tools to support decision-makers in setting adequate goals and monitoring the effects of undertaken actions. Considering the need for research on effective CE performance evaluation, this article presents a comprehensive analysis and comparison of CE indicators available at the micro level. Based on a systematic literature review, 19 such CE indicators were identified. The indicators were assessed and compared using the Delphi methodology. The suitability of each metric for a comprehensive evaluation of CE performance was analyzed taking account of the criteria related to analytical opportunities and potential application of CE indicators, together with the criteria related to organizational and operational issues of practical application of CE indicators. The usefulness of CE indicators for practical implementation in companies was determined from a managerial perspective, with particular emphasis on supporting the decision-making process. The comparison of CE indicators presented in this article is intended to facilitate the choice of a specific metric depending on the company’s needs and on the possibilities of its application.