Czech Academy of Sciences, Institute of Sociology

ABSTRACT A theorem of Frieze from 1985 asserts that the total length of the minimum spanning tree of the complete graph whose edges get independent lengths from the distribution converges to Apéry's constant in probability, as . We generalize this result to sequences of graphs that converge to a graphon . Further, we allow the lengths of the edges to be drawn from different distributions (subject to moderate conditions). The limiting total length of the minimum spanning tree is expressed in terms of a certain branching process defined on , which was studied previously by Bollobás, Janson and Riordan in connection with the giant component in inhomogeneous random graphs.

ABSTRACT Using pikeperch ( Sander lucioperca ) as a model species, we investigated the factors influencing fluctuations in the abundance of piscivorous intra‐annual cohorts and assessed the role of three distinct cohorts: extremely small (ES), ordinary (or mid‐sized) fingerlings, and piscivorous in shaping year‐class strength. Our analysis was based on 13 years of data (2003–2024) collected in the Lipno Reservoir, Czechia. Using LASSO for variable selection among 45 potential covariates and subsequent Generalized Additive Model (GAM) construction, our results revealed that a higher abundance of ES conspecifics and young‐of‐the‐year (YOY) perch, coupled with increased densities of large cladocerans in July, positively impacted the abundance of the piscivorous intra‐annual cohort. The abundance of 1+ pikeperch was positively influenced by the abundance of piscivorous and ordinary cohorts recorded in the preceding year. We concluded that all three intra‐annual cohorts contribute to the year‐class strength of pikeperch, with piscivorous and ordinary cohorts having a more direct effect, while ES intra‐annual cohorts indirectly support the piscivorous cohort by serving as prey.

This paper analyses temporality and the experience of increased speed in contemporary academia and its perceived influence on knowledge production. The study is grounded in theories of acceleration-related change in academia and examines the perceived effects of accelerated research processes on contemporary knowledge production, offering insights into the widespread use of questionable research practices (QRPs). Drawing on 36 focus group interviews with 172 researchers across seven European countries, the analysis reveals strikingly consistent perceptions of current reward and merit systems in academia, transcending differences in countries, disciplines, gender, and levels of seniority. These systems are widely perceived to reward speed and quantity at the expense of quality and integrity, thereby potentially undermining the robustness of the knowledge produced. The study thus shows a need for a stronger qualitative component in the assessment system, which aligns with the aims of the ‘research assessment reform movement’ (cf. DORA, CoARA). However, this paper argues that the research assessment reform movement needs to consider temporality in its efforts to reform research assessments. A stronger focus on ‘process time’ and ‘temporal autonomy’ is recommended to ensure that researchers and research units have adequate time to carry out all research tasks while maintaining integrity.

Introduction for the Winnicott special issue.

Abstract Sodium chloride (NaCl) is one of the best known and most studied materials in the history of materials science. It has a wide range of applications from material’s research, chemical industry, to common household use or as a material for sprinkling in winter. Interestingly, NaCl was recently also used as a catalyst for nanodiamond purification, rounding, and shape modifications; however, the origin of such an effect still remains unclear. This work is motivated to investigate the NaCl behavior deeper and reveal the cause, which could lead to such behavior. In this work, several NaCl powder samples and a single crystal of NaCl were studied by thermal analyses such as differential scanning calorimetry (DSC) and thermogravimetry (TG), mass spectrometry (MS), optical stereomicroscopy (OM), optical thermomicroscopy (OTM), and powder X-ray diffraction (XRPD). XRPD analysis was used to determine the structure and phase composition, confirming the presence of only NaCl. The OTM revealed an effect at ∼450 °C, determined as well by DSC, TG and also TMA methods, which corresponded to cracking and bouncing of NaCl grains. MS analysis proved the presence of a small content of H 2 O, which was released at temperatures similar to those where ND rounding was reported, indicating a possible contribution of water in the NaCl catalytic action on NDs.

The role of circadian misalignment has been implicated in metabolic health, not excluding glycemic control, but its role in type 1 diabetes mellitus (T1DM) has not been fully understood. The aim of the study was to investigate the relationship between the degree of circadian misalignment and the efficacy of glycemic control in T1DM patients. This cross-sectional study included 879 patients within the general Czech population who have been diagnosed with T1DM for a period of at least 10 years (mean HbA1C 52.9±0.4mmol/mol). The patients were aged 18-86 years and comprised 45% females. All participants filled out the Munich Chronotype Questionnaire (MCTQ) to assess their individual chronotype and calculate social jetlag (SJL). The individual chronotypes were also assessed using self-reporting best alertness time (BAmid). Sleep quality was self-assessed on a 4-point scale from 1 (best) to 4 (worst). T1DM management was evaluated through continuous glucose monitoring data (CGM) including the glycemia risk index (GRI). For the non-diabetic control group, we utilized data obtained from wave 5 of a nationally representative longitudinal Czech Household Panel Survey (CHPS), which involved 1757 subjects without diabetes aged 18-86 years. Data were analyzed through cross-sectional univariate and multivariate analyses. T1DM patients had later average chronotype and significantly higher SJL compared to controls. Across all adjusted models, higher SJL was consistently associated with T1DM. Within the T1DM cohort, increased SJL was positively associated with higher GRI (r=0.12, P=0.0029), while chronotype itself showed no independent association with glycemic control. Overall, metabolic markers showed better outcomes in T1DM patients than in control non-diabetic population. Social jetlag was robustly correlated with both T1DM and impaired glycemic management. These findings call for systematic examination of such characteristics in patients with T1DM and may open the door to taking circadian aspects into account when striving for optimal management of T1DM.

Moral competence and anxiety are essential factors in medical and psychology education, but evidence on how these variables interact across different testing conditions is limited. The present study examined whether moral competence differs between medical and psychology students, how it relates to anxiety levels, and whether test format and duration influence outcomes. A total of 717 students (620 medical, 97 psychology) completed the Moral Competence Test (MCT) and the State-Trait Anxiety Inventory (STAI). Participants were systematically (quasi-randomly) assigned to an online or paper-based version of the tests. Test duration was recorded in both formats. Group differences were analyzed using generalized linear models, with additional attention to the relationship between completion time and moral competence. Psychology students scored higher in moral competence than medical students, while anxiety remained elevated among medical students. Female students reported significantly higher trait anxiety than male students. No significant differences were found between online and paper-based formats in moral competence or anxiety outcomes. Longer test duration was associated with higher moral competence among medical students, although this relationship was correlational and should be interpreted cautiously. Findings confirm that moral competence declines during medical education while anxiety persists at a higher level, particularly among female students. In contrast, psychology students demonstrated stable or higher moral competence. The absence of differences between online and paper-based formats suggests that both are suitable for assessing moral competence and anxiety in academic settings. The observed association between test duration and moral competence highlights a potential area for further research but should not be interpreted causally.

In this paper, we experiment with novelty-based variants of OpenAI-ES, NS-ES and NSR-ES algorithms, and evaluate their effectiveness in training complex transformer-based architectures designed for the problem of reinforcement learning, such as Decision Transformers. We also test whether we can accelerate the novelty-based training of these larger models by seeding the training with a pretrained model. The experimental results were mixed. NS-ES showed progress, but it would clearly need many more iterations for it to yield interesting results. NSR-ES, on the other hand, proved quite capable of being straightforwardly used on larger models, since its performance appears as similar between the feed-forward model and Decision Transformer, as it is for the baseline objective-based OpenAI-ES.