Swarthmore College

What is the impact of democratic transition on the party politics of neighboring democratic nations? While existing scholarship on democratic diffusion primarily focuses on how democratization influences authoritarian regimes, it often overlooks the cross-border effects on neighboring democracies. This study addresses this gap by investigating the impact of democratic transitions on party polarization and the issue salience of democracy in countries with democratic or hybrid regimes. Using the Manifesto Project and V-DEM’s regime transitions data sets and employing a difference-in-differences design with staggered treatment adoption, our analysis reveals a counterintuitive effect: democratic transitions in one country leads to a decrease in party polarization over democracy in neighboring countries. We posit this decline is a long-term phenomenon, linked to the diminishing salience of democracy as a key issue in party manifestos after a short period of initial prominence. By shifting the scholarly focus of diffusion effects to party politics within democratic and hybrid regimes, we contribute to a more nuanced understanding of how democratization ripples beyond its borders, shaping the political landscape in unanticipated ways.

Abstract The Scarlet Pygmy Nannophya pygmaea Rambur, 1842 (Odonata: Libellulidae), the smallest described dragonfly species, is found across the Pacific coast and along the island chains of eastern Asia. Previous research has questioned whether N. pygmaea is potentially a complex of multiple species. Past studies have proposed a new species, N. koreana, based on mitochondrial genetic data, but the N. pygmaea complex remains unresolved. Using increased taxon sampling, we assessed genetic differentiation across populations and reconstructed evolutionary relationships of the N. pygmaea complex. From 141 COI-5P sequences, we calculated genetic structure through estimation of pairwise FST values among 10 populations and constructed a haplotype network to determine genetic differentiation, which revealed extremely high differentiation between northern populations (Japan, South Korea, China, and Laos) and southern peninsula/island chain populations (Malaysia, Singapore, Indonesia, and Vietnam). Species distribution models (SDMs) showed large stretches of less suitable habitat between regions populated by N. pygmaea. A lack of gene flow and geographical isolation between the clades supports these highly differentiated populations being described as separate species. Additionally, our SDMs explored the prevalence of present suitable habitats and how habitat suitability may shift between now and 2070. Our paleodistribution modeling provides insight into possible land migration routes that would allow N. pygmaea, as a weak flyer, to have dispersed to its present-day distribution. Ordination analysis of niche divergence between the northern and southern clades found no significant levels of niche differentiation or similarity between the 2 clades.

We introduce the notion of a “walk with jumps”, which we conceive as an evolving process in which a point moves in a space (here, mathbb {H}^2) over time, in a consistent direction and at a consistent speed except that it is interrupted by a finite set of “jumps” in a fixed direction and distance from the walk direction. Our motivation is biological; specifically, to use walks with jumps to represent the activity of a neuron over time (a “spike train”). This representation has distinctive properties, including a built-in “point of no return” property that may serve as a substrate for decision-making with progressive refinement over time. Moreover, because (in mathbb {H}^2) the walk is built out of a sequence of transformations that do not commute, the walk’s endpoint encodes aspects of the sequence of jump times beyond their total number. Importantly, this encoding is incomplete: quite different sequences of jump times may lead to the same endpoint. The main results of the paper use the tools of hyperbolic geometry to formalize and delineate the these behaviors.

In traditional design courses, prototyping is initiated after a problem has been identified, constraints have been defined, and multiple solutions have been conceived. Accordingly, students tend to narrowly perceive prototyping as a step toward a designated endpoint (e.g., building and testing a final product) rather than as a flexible method for expanding their understanding throughout a design project. We designed a "prototyping the need" exercise and piloted it in an undergraduate course focused on the early stages of the health technology innovation process. Students defined important questions about their unmet needs and then built models to help them explore the answers and deepen their understanding of the problem, the population it affects, and/or the desired outcome if the need is solved. The exercise provided students with the opportunity to build hands-on prototyping/modeling skills earlier than usual in the design process, expanded their understanding of prototyping as an exploratory tool, and strengthened their engagement and empathy. In this article, we describe the "prototyping the need" method, spotlight two student projects, and share lessons from the pilot. The online version contains supplementary material available at 10.1007/s43683-025-00198-2.

Abstract Frame-relative fictive motion describes a linguistic phenomenon whereby the motion of an entity is communicated via the – fictive – motion of stationary background objects. For instance, a woman’s experience of riding on a fast train might be described as The trees rushed past her . Such fictive-motion constructions allow the addressee to see the point of view of a character in a narrative, but in sign languages, they perform additional tasks. Our quantitative study of fictive motion in narratives in German Sign Language (DGS) demonstrates how it allows signers to depict distance, speed, and point of view while circumventing constraints imposed by anatomy/physiology and phonology. Data from nine additional sign languages confirm this range of uses. In contrast to spoken languages, sign languages allow the combination of factive- and fictive-motion depiction in one sentence, posing problems for a purely morphological analysis of the movement parameter in classifier constructions. This work shows that both cognitive-perceptual and anatomical matters shape sign language grammars.

Any pair of intersecting cylinders on a translation surface is "coherent," in that the geometric and algebraic intersection numbers of their core curves are equal (up to sign).In this paper, we investigate when a pair of multicurves can be simultaneously realized as the core curves of cylinders on some translation surface.Our main tools are surface topology and the "flat grafting" deformation introduced by Ser-Wei Fu.

ABSTRACTMultilevel selection (MLS) is a foundational framework that expands the concept of natural selection beyond the traditional focus on individuals or genes to larger units, like groups. Despite strong empirical support and applications in a broad range of biological fields, MLS, often referred to as group selection, has a controversial history, which has impeded its wide use and led to incorrect inferences on the sources and strength of selection. Here, we explore how MLS is currently presented to undergraduate biology students by analyzing the content of nine commonly used Evolutionary Biology and Animal Behavior textbooks. We ask whether and how the textbooks describe MLS—as part of the toolbox of evolutionary theory, as a controversial topic, or not at all. Using qualitative textual analysis and descriptive statistics, we found that MLS was mentioned in all of the textbooks analyzed, although usually only in the context of the evolution of social behavior. MLS was generally dismissed as unimportant when compared to individual selection and given less space and fewer examples than kin selection. We highlight the value of a more accurate presentation of MLS and present suggestions for teaching MLS in undergraduate courses based on empirically supported practices in biology education.

ABSTRACTRecent and abrupt deviations in U.S. climate and energy policies are shifting the United States away from a more sustainable future toward greater fossil‐fuel use that will accelerate global warming. These new priorities go against the wishes of the American people as measured by many nationally representative surveys, and they ignore the scientific consensus regarding climate change and its deleterious consequences. This new agenda will harm the physical and mental health of Americans, imperil the U.S. economy, weaken American leadership in science, and increase geopolitical instability. Despite the frightening nature of these unprecedented departures from past climate‐energy policies, successfully combating the climate crisis is achievable and will improve well‐being, grow the economy, enhance security, and promote independence. Insights derived from social psychology can motivate positive actions so that government policies represent the will of their people and benefit from the knowledge of climate scientists, social researchers, economists, and health experts.