The numerical range in the quaternionic setting is, in general, a non-convex subset of the quaternions. The essential numerical range is a refinement of the numerical range that only keeps the elements that have, in a certain sense, infinite multiplicity. We prove that the essential numerical range of a bounded linear operator on a quaternionic Hilbert space is convex. A quaternionic analogue of Lancaster theorem, relating the closure of the numerical range and its essential numerical range, is also provided.

I aim in this article to contribute two points to the ongoing discussion regarding strong DDS and modal collapse. First, I will examine a recent version of the modal collapse objection formulated by R. T. Mullins, demonstrating that one can modify the argument to survive its most forceful rejoinder. Having established the cogency of Mullins's modal collapse argument, I next aim to heighten the severity of the conclusion. In particular, I demonstrate that the success of the modal collapse argument entails a moral collapse wherein well-established principles of ethical reasoning fail. Finally, I examine a recent attempt by Katherine Rogers to undercut some of the unwelcomed results of a modal collapse via an appeal to the theistic multiverse. I conclude that this manoeuvre proves ineffective against the moral collapse objection.

The theory of utility is a well-known method of constructing insurance premiums (see e.g., Newton et al. (1986) Actuarial Mathematics. Itasca, Illinois: The Society of Actuaries.). Furman and Zitikis ((2008) Insurance: Mathematics and Economics, 42, 459–465.) proposed an alternative method using the mean value of a weighted random variable. According to this approach, for various choices of weighting, popular premiums such as net premium, modified variance premium, Esscher premium, and Kamps premium are obtained. On the other hand, some premiums cannot be obtained with this method, such as the premium of the exponential principle. In this paper, we provide a complementary theory by introducing a family of unimodal weighted distributions for which the mode is a premium principle.

Political scientists have long viewed values as a source of constraint in political belief systems. More recently, scholars have argued that values—particularly moral values—contribute to polarization. Yet, there is little direct and systematic research on which values are perceived as moral values. We examine 21 values, including Schwartz’s values, political values, and moral foundations. Drawing on a broad literature on cooperation, we first develop theoretical expectations for the extent of value moralization both between and within value systems. We next argue that this moralization matters because it intensifies the effects of value disagreement on social polarization. Using a probability-based survey of the US and an embedded conjoint experiment, we find substantial variation in moralization across values, and that highly moralized values are more polarizing. Our research brings together competing literatures on values and shows how moral values differentially shape polarization.

Between 2006 and 2021, the Hungarian Twin Registry (HTR) operated a volunteer twin registry of all age groups (50% monozygotic [MZ], 50% dizygotic [DZ], 70% female, average age 34 ± 22 years), including 1044 twin pairs, 24 triplets and one quadruplet set. In 2021, the HTR transformed from a volunteer registry into a population-based one, and it was established in the Medical Imaging Centre of Semmelweis University in Budapest. Semmelweis University’s innovation fund supported the development of information technology, a phone bank and voicemail infrastructure, administrative materials, and a new website was established where twins and their relatives (parent, foster parent or caregiver) can register. The HTR’s biobank was also established: 157,751 individuals with a likely twin-sibling living in Hungary (77,042 twins, 1194 triplets, 20 quadruplets, and one quintuplet) were contacted between February and March of 2021 via sealed letters. Until November 20, 2022, 12,001 twin individuals and their parents or guardians (6724 adult twins, 3009 parents/guardians and 5277 minor twins) registered, mostly online. Based on simple self-reports, 37.6% of the registered adults were MZ twins and 56.8% were DZ; 1.12% were triplets and 4.5% were unidentified. Of the registered children, 22.3% were MZ, 72.7% were DZ, 1.93% were triplets, and 3.05% were unidentified. Of the registered twins, 59.9% were female (including both the adult and minor twins). The registration questionnaire consists of eight parts, including socio-demographic and anthropometric data, smoking habits and medical questions (diseases, operations, therapies). Hungary’s twin registry has become the sole and largest population-based twin registry in Central Eastern Europe. This new resource will facilitate performing world-class modern genetic research.

This article considers the role of experts and their interaction with the legal system to better understand the benefits and potential dangers of expert evidence to fact-finders in trials. Medical experts are indispensable to the administration of justice as litigation ranges beyond what judges or juries comfortably deal with as facts of everyday life. This would render courts, absent expert evidence, vastly under-equipped in making decisions of fact. However, the dangers of surrendering authority to experts or of misunderstanding their role must be considered to ensure that expert evidence is used to benefit the administration of justice.

We consider the homology theory of étale groupoids introduced by Crainic and Moerdijk [A homology theory for étale groupoids. J. Reine Angew. Math. 521 (2000), 25–46], with particular interest to groupoids arising from topological dynamical systems. We prove a Künneth formula for products of groupoids and a Poincaré-duality type result for principal groupoids whose orbits are copies of an Euclidean space. We conclude with a few example computations for systems associated to nilpotent groups such as self-similar actions, and we generalize previous homological calculations by Burke and Putnam for systems which are analogues of solenoids arising from algebraic numbers. For the latter systems, we prove the HK conjecture, even when the resulting groupoid is not ample.

In this paper, we introduce a unique dataset derived from a survey conducted among 450 Syrian refugee workers and the owners/managers of the firms in which they are employed in Istanbul, Turkey. We utilise this data to investigate the connection between the wage-productivity gap and perceived economic and social discrimination. The findings of the study indicate that individuals facing a wider wage-productivity gap tend to report higher levels of economic and social discrimination. These results remain consistent even after incorporating various variables at both the worker and firm levels into the analysis. These findings imply potential policy recommendations that policymakers should take into account.

Americans generally celebrate the abstract principle of diversity, but research suggests that they have a comparatively lower (1) favorability towards policies that promote diversity and (2) sense of personal closeness with others from diverse backgrounds. The current study analyzes nationally representative survey data to assess such “principle-policy gaps” and “principle-personal gaps” in Americans’ diversity attitudes. We find that these attitudinal gaps indeed exist and are substantial in the general population. We also consider how individual-level factors relate to these attitudinal gaps. Following common findings in previous research, we find that participant racial identity and political partisanship have statistically significant relationships with these attitudinal gaps. But our overall findings illustrate that principle-policy gaps and principle-personal gaps in diversity attitudes are fairly substantial and prevalent across Americans who vary by race, politics, and several other individual-level factors. We consider our findings in the current social and political context, and we discuss directions for future inquiry.

This article investigates legislators’ willingness to talk about gender and women during policy making discussions, asking whether it is conditional on their sex or partisanship in environments where party discipline does not constrain their speech. The Canadian Senate offers a case of a legislature with low or absent party discipline. A quantitative content analysis of nearly 1,000 Senate committee meetings confirms that sex is a primary indicator of legislators’ inclination to talk about gender and women. Moreover, women senators who sit on committees with a critical mass of women members (30% or greater) are more likely to talk about gender and women, making the case for the importance of women’s descriptive representation. Partisanship and independence had no significant effect on senators’ propensity to discuss women. The findings suggest that partisanship does not constrain legislators’ representation of women in environments with low party discipline.

The NIST Workshop: Integrating Crystallographic and Computational Approaches to Carbon-Capture Materials for the Mitigation of Climate Change took place from October 31–November 1, 2023 at the National Cybersecurity Center of Excellence (NCCoE) Compound in Rockville, MD, which is an off-campus NIST facility. This workshop provided a forum for experimentalists and theorists working on the structural aspects of CO2 capture and sequestration materials to review the current state of the art in this field and discuss opportunities for collaborative research required to develop tools for rapid determination of the structure and its effect on the direct air capture performance in porous solid sorbents. We had a total of 33 international participants (18 invited speakers) from 17 institutions who were experimentalists and theorists from academia, government, and industry. The workshop was a great success.

Infections cause substantial morbidity and mortality among patients receiving care in outpatient hemodialysis facilities. We describe comprehensive infection prevention assessments by US public health departments using standardized interview and observation tools. Results demonstrated how facility layouts can undermine infection prevention and that clinical practices often fall short of policies.

Let ${\mathcal G}$ be a linear algebraic group over k, where k is an algebraically closed field, a pseudo-finite field or the valuation ring of a non-archimedean local field. Let $G= {\mathcal G}(k)$. We prove that if $\gamma\in G$ such that γ is a commutator and $\delta\in G$ such that $\langle \delta\rangle= \langle \gamma\rangle$ then δ is a commutator. This generalises a result of Honda for finite groups. Our proof uses the Lefschetz principle from first-order model theory.