Spherical robots can conduct surveillance in hostile, cluttered environments without being damaged. Their protective shell can safely house sensors and sensitive components. The pendulum-based spherical robot provides a platform (yoke) for a camera to be housed inside the protective hull. However, lateral oscillations, also known as wobble, become prominent when operated at low speeds, leading to shaky camera feedback. These oscillations are caused by the coupling between the forward and steering motions due to nonholonomic constraints. Designing a controller to limit wobbling in these robots is challenging due to their underactuated nature. In this paper, we propose a model-based (wobble-free) controller to navigate a pendulum-steered spherical robot to perform wobble-free turning maneuvers consisting of circular arcs and straight lines. The model is developed using Lagrange-D’Alembert equations and accounts for the coupled forward and steering motions. Furthermore, we also propose quantifiable metrics for wobble by deriving expressions for radius of curvature, precession rate, wobble amplitude, and wobble frequency during circular motions and designed an input–output feedback linearization-based controller to control the robot’s heading direction and wobble. Additionally, we extend the controller’s capabilities to handle point-to-point navigation, enabling the robot to execute more complex and goal-oriented trajectories. This research ensures the robot maintains wobble-free motion across diverse paths, enhancing its navigational autonomy and the quality of camera feedback. Overall, the proposed controller enables a teleoperator to command a specific forward velocity and pendulum angle as per the desired turning radius or destination while effectively limiting the robot’s lateral oscillations.

Fraise mowing is a turfgrass cultivation practice used to mechanically control annual bluegrass via a combination of physical removal and seedbank depletion. Research was conducted to determine whether fraise mowing could restore the efficacy of annual bluegrass control herbicides lost due to resistance. Herbicide treatments were applied to plots within separate fraise-mowed and non-fraise–mowed experiments conducted on a hybrid bermudagrass golf course fairway infested with annual bluegrass that became resistant to herbicides from Groups 2, 3, 5, and 29. Fraise mowing was performed on June 18, 2024, and June 23, 2025, to a 1.3-cm depth. Herbicides tested included diquat dibromide, flumioxazin, foramsulfuron, glufosinate, glyphosate, indaziflam, metribuzin, oxadiazon, prodiamine, pronamide, simazine, tetflupyrolimet, and thiencarbazone + foramsulfuron + halosulfuron. Herbicides were applied according to label directions at preemergence, early postemergence, mid-postemergence, or late postemergence timings during 2024 to 2026. In the fraise-mowed experiment, indaziflam, tetflupyrolimet, prodiamine, pronamide, simazine, and metribuzin provided 86% to 100% control of annual bluegrass by 12 wk after initial treatment (WAIT) and 61% to 88% by 24 WAIT. Without fraise mowing, these herbicides provided ≤53% and ≤73% control at 24 WAIT in 2024 and 2025, respectively. Increased efficacy may be related to a reduction in the annual bluegrass seedbank from fraise mowing because the practice reduced plant counts in nontreated check plots by 75% to 88% each year. Applications of diquat dibromide and flumioxazin mid-postemergence provided 18% to 34% control of annual bluegrass at 6 WAIT in the fraise-mowed experiment; whereas these same herbicides provided ≤10% control when they were applied to non-fraise–mowed hybrid bermudagrass. Mid-postemergence applications of glufosinate and glyphosate and late postemergence applications of foramsulfuron and thiencarbazone + foramsulfuron + halosulfuron performed similarly in both experiments. Restored use of residual herbicides lost due to resistance may remove barriers to adopting the practice of fraise mowing for annual bluegrass control.

We use new macroevolutionary rate estimates to resolve the dynamics of severe versus background extinction through the history of a major, globally distributed, Paleozoic zooplankton clade, the graptoloids. Our data span one of the “Big Five” mass extinctions, the Late Ordovician Mass Extinction (LOME), and several secondary, severe extinction events. We use cohort survivorship curves to derive both “instantaneous” rates and smoothed rates based on “natural” time-bin intervals that honor the structure of the data. We avoid the approximation of many approaches that average rate estimates within essentially arbitrary time bins.

We find that 63% of graptoloid extinctions lie within intervals classified previously as “background” extinction; only 7% lie within the LOME, and the remainder lie within the spans of 15 other secondary extinction events spread through the Ordovician and Silurian. Extinction rate magnitudes define a continuous, unimodal distribution. Background extinction in the graptoloids is not stochastically uniform but includes many more high-rate pulses than expected under a null model of uniform, memoryless extinction. Our results support the inference of pulsed extinction in the marine realm, with pulses occurring on timescales much finer than the standard age divisions of the Ordovician and Silurian periods. The LOME and secondary extinction events are not characterized by instantaneous extinction rates that are higher than so-called background. Instead, extinction events are distinguished from background by increased duration of their component, short-lived pulses of elevated extinction, and the LOME represents a protracted interval with multiple such pulses and little time for faunal recovery.

Our results are consistent with the notion that, whereas a mass or severe extinction may have an exceptional or singular initial trigger, the effects of that trigger propagate out to global-scale species loss via a complex web of processes that are common to many extinction episodes and may take significant time.

This article explores the evolution of school dress code policies in the United States as a critical lens into the workings of public education, authority, and exclusion. Focusing on metropolitan Seattle as a case study, the research traces the shift from informal appearance norms to formalized and punitive dress code enforcement from the 1950s to the present. Rather than functioning as neutral guidelines, dress codes have historically reinforced gendered, racialized, and class-based hierarchies under the guise of order and safety. By situating dress policies within broader political and social transformations—including student rights movements, the rise of zero-tolerance policies, and recent federal investigations—this article demonstrates how dress codes have become tools of gatekeeping that shape access to learning and belonging in public schools. In highlighting moments of resistance and change, this study interrogates the role of schools in regulating identity and offers a historical foundation to understand contemporary inequities in educational discipline and policy.

Let K be a number field with ring of integers $\mathcal {O}_K$, and let $f(x)\in \mathcal {O}_K[x]$ be a monic, irreducible polynomial. We establish necessary and sufficient conditions in terms of the critical points of $f(x)$ for the iterates of $f(x)$ to be monogenic polynomials. More generally, we give necessary and sufficient conditions for the backward orbits of elements of $\mathcal {O}_K$ under $f(x)$ to be monogenerators. We apply our criteria to construct novel examples of dynamically monogenic polynomials, yielding infinite towers of monogenic number fields with the backward orbit of one monogenerator giving a monogenerator at the next level.

We give a general construction of the motivic path space based at tangential basepoints, extending previous works of P. Deligne, A. B. Goncharov and M. Levine, which were limited to ordinary basepoints or to specific varieties. Given a smooth variety over a field endowed with a simple normal crossings divisor, we encode its tangential basepoints using the language of logarithmic geometry. Building on the recent construction by F. Binda, D. Park and P. A. Østvær of a stable $\infty $-category of $\mathbb {A}^1$-invariant logarithmic motives and its comparison with the usual category of motives, we define in a functorial manner the associated motivic pointed path spaces. In the presence of a motivic t-structure, truncating yields the motivic fundamental groupoid. In general, we construct Betti and de Rham realization functors for logarithmic motives (linearizing the construction of F. Binda, D. Park and P. A. Østvær for the Betti case) and we show that the periods of the motivic fundamental groupoid are given by regularized iterated integration of logarithmic differential $1$-forms, thus yielding a general version of Chen’s theorem with tangential basepoints.

Establishing causality in nutritional science is difficult. Human diets are complex, and individuals vary substantially in how they respond to dietary exposures. The nutrition literature mostly relies on observational studies, which are vulnerable to confounding and measurement error. Twin-based randomized controlled trials (RCTs), especially the co-twin control design, offer a compelling methodological solution to many of these challenges. This design enables researchers to distinguish genetic from environmental influences on health outcomes. The present scoping review was conducted to systematically map twin RCTs in nutrition science, evaluate their methodological approaches, and identify gaps and opportunities for future research. A comprehensive search across clinical trial registries and electronic databases yielded only 13 eligible studies, demonstrating that co-twin randomized dietary interventions remain rare relative to standard study designs using nontwins or twins assigned to the same arm. The interventions used in these eligible RCTs could be classified into four groups: dietary pattern interventions, nutrient- or supplement-based interventions, dietary component modification, and behavioral or multimodal interventions. This limited number of studies may be explained by recruitment challenges and concerns about generalizability. Greater international collaboration, standardized trial protocols, and integration of emerging technologies could expand the utility of twin designs in nutrition science.

In an effort to conceptually replicate prior work on persuasion and campaign effects, we conducted three randomized survey experiments to evaluate the persuasive effects of political advertisements during the 2025 Canadian federal election. We tested a total of 15 campaign advertisements on 3,346 respondents. Our results are consistent with what seems to be three robust findings about the effects of campaign advertising: (1) they can change candidate evaluations and vote intentions, but (2) the effects are very small, and most importantly, (3) persuasive treatment effects seem to be mostly homogeneous. We offer new empirical evidence that strengthens previous findings on the homogeneity of persuasive treatment effects of political advertising in Canada that challenges the extent to which microtargeting improves candidates and advocacy groups’ ability to sway public opinion.

This paper investigates the conditions under which women are more likely to represent interest groups in parliamentary hearings, shifting attention from the content of advocacy to the identity of advocates. While existing research has focused on how interest groups gain access to legislative venues, it has largely overlooked who delivers these messages and how messenger characteristics shape political representation. Drawing on theories of gender representation, interest group advocacy, and source effects, we develop a framework that distinguishes between structural and strategic representation and examine whether gender is deployed as a symbolic and relational resource in legislative settings. Using an original dataset covering all interest group appearances in the Spanish Parliament from 1996 to 2023, and hierarchical logistic regression models with Bayesian inference, we analyze how organizational, institutional, and contextual factors shape gendered representation. The findings show that citizen groups are significantly more likely than economic organizations to be represented by women, and that female representation increases with the proportion of women MPs on parliamentary committees. Gendered patterns also vary across policy domains and hearing characteristics. Importantly, the results provide evidence consistent with strategic adaptation: interest groups appear more likely to select female representatives in gender-diverse institutional environments, suggesting that gender functions as a form of strategic signaling rather than solely reflecting internal organizational structures. These findings contribute to research on interest groups and political representation by highlighting how identity operates as a political resource, with implications that extend beyond parliamentary lobbying to broader debates on descriptive and substantive representation.

This paper analyzes two interrelated strategies for using mechanistic evidence as a political instrument of social power, the Wedge and the Buttress. I compare two policy skirmishes over contraception and abortion pills. First, Pro-Life critics of emergency contraception aimed to undermine the switch to over-the-counter access. They drove a Wedge into the proposed mechanism, stalling policy change by raising politically motivated doubts. Second, Pro-Choice advocates of medication abortion tried counteracting mail-order restrictions. They Buttressed with new evidence to preempt their opponents before the COVID-19 pandemic. I explain the interplay between these strategies, their political motivations, and their relative empirical character.

There is limited research into the experiences and impact on wellbeing, of laypersons informally supporting people seeking asylum (PSA) within the United Kingdom. This study addresses this topic within the context of the Bibby Stockholm barge. An interpretivist philosophical paradigm and qualitative strategy were employed. A combination of purposive and snowball sampling was utilized in recruiting nine participants aged 50–80, six male and three female, and all of Caucasian ethnic origin. Data were collected using semi-structured one-to-one interviews and analyzed using Thematic Analysis. Three themes emerged. First, Participants situated their motivations to volunteer within the context of social justice, informed by previous life experiences, personal morals and a reaction to the sociopolitical context PSA are forced to navigate. Second, volunteers’ experiences reflected the interactions of community. To this end, community is considered as an ever-changing “machine” where processes such as welcoming, loss and belonging form the cogs, which drive its evolution. Finally, volunteers described the way their experience affected their wellbeing—the wellbeing equation. Overall, volunteers described an overwhelmingly positive experience and provide accounts of experiencing increased wellbeing. However, volunteers also faced challenges damaging to wellbeing, employing protective mechanisms to mitigate these. This relationship between volunteering with PSA and wellbeing is summarized in the development of a revised conceptual framework contextualizing the effects of volunteering on volunteer health and wellbeing. The future application of this framework across different voluntary fields may improve understanding of what it means to volunteer and thus universal volunteer retention and outcomes.