In the current context of democratic backsliding, different political systems, such as democracies and autocracies, as well as political differences between democracies, play an important role in shaping economic relationships. Yet, studies of political factors in international business mostly focus on destination country politics or political distance, conceptualized as cross-country differences in political institutions. We argue that these approaches do not capture the full range of political differences between countries. We disaggregate political distance into polity distance (the difference between political institutions), politics distance (ideological differences between governing parties), and policy distance (substantive differences in policies). In a novel cross-country panel dataset, we combine firm internationalization with country-level political characteristics. We find that polity, politics, and policy distances negatively impact firm internationalization, with polity distance having a stronger negative effect on the internationalization of firms from more democratic countries, and politics distance having a stronger negative effect on firms from countries with right-wing governments, highlighting that these distances have both absolute and directional effects.
We investigate whether it is typical for a sparse graph to be uniquely characterized by its adjacency spectrum up to isomorphism. Setting the stage for our main results, we start by proving that the giant component of an Erdős–Rényi graph is cospectral when the average degree is sufficiently small. The proof relies on the existence of a specific pendant tree, combined with a method by Schwenk that swaps trees to construct a cospectral mate.It seems possible that pendant trees are essentially the only obstruction, meaning that the giant should become characterized by spectrum with high probability if one prunes these by considering the 2-core. The majority of the paper is devoted to theoretical and numerical evidence supporting this concept. Our main theorem in this direction establishes that local switching methods cannot cause the 2-core to be cospectral. We also discuss generalized cospectrality.
This study presents new experimental data on the effect of oxygen fugacity (fO2) and bulk composition on phase equilibria and liquid lines of descent in alkali basalts. Crystallisation experiments were performed at one atmosphere, in the temperature range 1220–1050 °C and at fO2 conditions corresponding to fayalite–magnetite–quartz (FMQ) equilibrium and the following log-unit deviations from this equilibrium: FMQ-1, FMQ + 1.5 and FMQ + 3. Experiments were grouped into two series, those on primitive compositions (9.9–11.9 wt K_ D_ Fe^2+-Mg^ Ol- Melt and K_ D_ Fe^T-Mg^ Ol- Melt in alkaline systems, with the latter formulated as: K_ D_ Fe^T-Mg^ Ol- Melt(± 0.012, a.a.d.)=0.442 (± 0.029)+0.287 (± 0.035)[X_SiO_2]-0.442(± 0.027)[X_Na_2O+X_ K_2O/X_SiO_2]- 0.168(± 0.022)[X_Fo]-0.138(± 0.008)1/(1-[Fe^3+/ΣFe]) where X_i is the mole fraction of i in the melt, X_Fo is molar MgO/(MgO + FeOtot) of olivine, Fe3+/ΣFe represents Fe valence in the melt and a.a.d. is the average absolute deviation. We also present a simple model for estimating K_ D_ Fe^T-Mg^Cpx-Melt : K_ D_ Fe^T-Mg^Cpx-Melt(± 0.028,a.a.d.)=-1.00 (± 0.064)+2.129 (± 0.063)[T (^∘C)/1000]- 1.675(± 0.021)[Mg#] +0.144(± 0.006)1/1-[Fe^3+/ΣFe] where Mg# is molar MgO/(MgO + FeOtot) of clinopyroxene and Fe3+/ΣFe represents Fe valence in the melt. These new formulations allow equilibrium K_ D_Fe-Mg^Mineral-Melt to be estimated more reliably in oxidising, alkaline systems where Fe3+/ΣFe is high.
Motivation has long been recognised as a key factor in students’ learning, achievement, and engagement in mathematics. In this systematic review, we examine how a situative perspective on motivation has been conceptualised, theorised, and operationalised in recent research on learning and instruction in mathematics. Specifically, we analyse the ways in which situatedness is recognised and captured across studies positioned across major motivational frameworks (i.e., expectancy-value, interest, self-determination, achievement goal, and social-cognitive theory), and the methodological approaches employed (i.e., participants, analytical methods, data sources, and measures) until the first half of 2025. Our review identifies 76 studies that focus on situatedness in the motivation for learning mathematics, the majority of which are empirical, quantitative, and employ variable-centred approaches. Across the motivational theoretical frameworks, situated expectancy-value theory is the most prevalent and survey methods dominate. Although all studies recognise the importance of situatedness or examine situatedness in research, its temporal and contextual aspects are addressed mostly separately, with micro- (e.g., activities) and mezzo-levels (e.g., classroom) dominating the contextual perspective. This systematic review advances motivational research by highlighting key aspects of situatedness in recent studies of motivation, examining its role in research on motivation, and suggesting future directions for research on learning mathematics. Following the presentation of findings and discussion, we also highlighted contributions to this special issue.
Abstract Background Adverse events across the lifespan have been linked to poorer health outcomes, but the biological mechanisms remain unclear. The aim of this study was to quantify the independent and joint associations of adversity experienced in childhood and/or adulthood with molecular, clinical and functional markers of biological ageing. Methods We analysed data from up to 153,557 middle-aged and older adults in the UK Biobank. Adversity was assessed through questionnaires capturing five types of childhood and adulthood adverse events. Biological ageing markers included metabolomic age (MileAge) delta, a metabolomic mortality profile, the frailty index, telomere length and grip strength. Regression models were adjusted for age, sex, education, income, ethnicity and neighbourhood deprivation. Results Across childhood and adulthood exposures, adversity and its severity were most consistently associated with higher frailty index values. The strongest associations were observed in individuals exposed to multiple types of adverse events. Individuals who experienced adversity in both childhood and adulthood also had a metabolite-predicted age exceeding their chronological age and lower grip strength. Abuse was more consistently associated with biological ageing markers than neglect. Conclusions Cumulative exposure to adversity across childhood and adulthood is associated with older biological ageing profiles across multiple domains. These findings highlight biological ageing as a potential pathway linking adversity to poor health outcomes and premature mortality.
