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This paper investigates the flow and density field around a spinning solid spheroid with a given aspect ratio, immersed in a rotating stratified fluid. First, we derive the general system of equations governing such flows around any solid of revolution in the limit of infinite Schmidt number. We then present an exact analytical solution for a spinning spheroid of arbitrary aspect ratio. For the specific case of a sphere, we provide the diffusive spin-up solution obtained via an inverse Laplace integral. To validate the theoretical results, we experimentally reproduce these flows by spinning spheroids in a rotating tank filled with stratified salt water. By varying the stratification intensity, the angular velocities of the spheroid and the rotating table, and the spheroid’s shape, we explore a broad parameter space defined by Froude, Reynolds and Rossby numbers and aspect ratio. Using particle image velocimetry to measure the velocity field, we demonstrate excellent agreement between theory and experiments across all tested regimes.
The problem of a uniform current interacting with bodies submerged beneath a homogeneous ice sheet is considered, based on linearised velocity potential theory for fluid and elastic thin plate theory for ice sheet. This problem is commonly solved by the boundary element method (BEM) with the Green function, which is highly effective except when the Green function becomes singular, and the direct solution of the BEM is no longer possible. However, flow behaviour, body force and ice sheet deflection near the critical Froude numbers are of major practical interest, such as in ice breaking. The present work successfully resolves this challenge. A modified boundary integral equation (BIE) is derived, which converts the singular Green function term to a far-field one and removes the singularity. The BIE is then imposed at infinity for additional unknowns in the far field. It is proved that the solution is finite and continuous at the critical Froude number $F = F_c$, where the body starts generating travelling waves, and finite but discontinuous at depth-based Froude number $F = 1^\pm$. Case studies are conducted for single and double circular cylinders and an elliptical cylinder with various angles of attack. A comprehensive analysis is made on the hydrodynamic forces and the generated flexural gravity wave profiles, and their physical implications are discussed. It is also concluded that the method developed in this paper is not confined to the present case but is also applicable to a variety of related problems when the BEM fails at the critical points.
Longstanding public support for the Supreme Court of Canada is well-documented and contributes to its public legitimacy. However, the sources of this support and how vulnerable it may be to political factors or negative coverage of events are not well understood. In February of 2023, Justice Russell Brown took a leave of absence from the Supreme Court following a conduct complaint under review by the Canadian Judicial Council. Justice Brown retired from the bench in June of that year, before the CJC concluded its investigation. In the intervening period, media coverage of the events that prompted the attention from the CJC thrust the Court into the spotlight. Using data from an original two-wave survey experiment (n = 1,222) from May and November of 2023, we investigate whether perspectives toward the circumstances surrounding Brown’s retirement hurt perceptions of the Court’s legitimacy. We find that the event did not disrupt support for the Court over time but also point to the ways in which opinion toward the Court changed pre- and post-resignation. These findings suggest that support toward Canada’s high court is at present largely stable even in the case of negative coverage of a high-profile event. However, we also acknowledge the potential vulnerabilities that negative coverage of the Court may present.
This paper presents an archaeological material science study of pottery production and use at the Bronze Age Minoan town of Palaikastro, east Crete, from Middle Minoan IIA to Late Minoan IIIA2 (c. 1850 to 1300 BC), through petrographic analysis of thin sections and wavelength dispersive X-ray fluorescence spectroscopy. The compositions of 288 archaeological samples are compared with geological references collected from the site and its adjacent hinterland. The results of this study indicate that throughout this period the majority of the archaeological pottery assemblage was probably produced using materials from a small number of geological outcrops local to the town; however, the manner in which these resources were utilised changed significantly over time, particularly between the Proto- and Neopalatial periods.
Recent years have seen a remarkable revival of research on Cassius Dio and his Roman History, including the publication of numerous volumes of collective essays, and this has been accompanied by a much higher estimation of his achievement than used to be customary. This article seeks to assess the progress made on a range of key issues relating to Dio and his history and to point ahead to further directions for research. The chief topics considered are Dio’s career as senator and historian, central aspects of his history (transmission, sources and models, structure, speeches), and Dio’s handling of politics and system change.
The extensional rheology of dilute suspensions of spheres in viscoelastic/polymeric liquids is studied computationally. At low polymer concentration $c$ and Deborah number $\textit{De}$ (imposed extension rate times polymer relaxation time), a wake of highly stretched polymers forms downstream of the particles due to larger local velocity gradients than the imposed flow, indicated by $\Delta \textit{De}_{\textit{local}}\gt 0$. This increases the suspension’s extensional viscosity with time and $\textit{De}$ for $De \lt 0.5$. When $\textit{De}$ exceeds 0.5, the coil-stretch transition value, the fully stretched polymers from the far-field collapse in regions with $\Delta \textit{De}_{\textit{local}} \lt 0$ (lower velocity gradient) around the particle’s stagnation points, reducing suspension viscosity relative to the particle-free liquid. The interaction between local flow and polymers intensifies with increasing $c$. Highly stretched polymers impede local flow, reducing $\Delta \textit{De}_{\textit{local}}$, while $\Delta \textit{De}_{\textit{local}}$ increases in regions with collapsed polymers. Initially, increasing $c$ aligns $\Delta \textit{De}_{\textit{local}}$ and local polymer stretch with far-field values, diminishing particle–polymer interaction effects. However, beyond a certain $c$, a new mechanism emerges. At low $c$, fluid three particle radii upstream exhibits $\Delta \textit{De}_{\textit{local}} \gt 0$, stretching polymers beyond their undisturbed state. As $c$ increases, however, $\Delta \textit{De}_{\textit{local}}$ in this region becomes negative, collapsing polymers and resulting in increasingly negative stress from particle–polymer interactions at large $\textit{De}$ and time. At high $c$, this negative interaction stress scales as $c^2$, surpassing the linear increase of particle-free polymer stress, making dilute sphere concentrations more effective at reducing the viscosity of viscoelastic liquids at larger $\textit{De}$ and $c$.
The prehistoric human habitation of the Tibetan Plateau (TP) is well evidenced by the archaeological record, but poorly constrained in time and space. To test the plausibility of in situ survival during the last glacial maximum (LGM) and the coldest periods of the Pleistocene, this paper gauges the effects of LGM conditions and varying local ice coverage on the climate. Three different climate model scenarios are generated, and their outputs are used to drive vegetation simulations. This allows us to evaluate 10 archaeological sites that show evidence of human activity either pre- or post-LGM as possible human refugia. The results show that the higher the level of ice coverage on the plateau, the colder and drier the climate becomes, and barren unproductive land extends farther south. However, there are sites that remain habitable in all scenarios, with the southern and northeastern plateau identified as the areas with the highest likelihood of refugia during the LGM, specifically at the locations of Baishiya Karst Cave and Siling Co. There is a high probability of the TP being habitable during the LGM, as even the scenario with the most ice yields some regions with favourable conditions that are within the habitability criteria.
Chronic pulmonary regurgitation following tetralogy of Fallot repair burdens the right ventricle. This study evaluated early outcomes of pulmonary valve reconstruction using right atrial tissue versus standard transannular patch repair.
Methods:
A retrospective analysis of 412 tetralogy of Fallot patients (2014–2024) was conducted: Atrial Valve Group (n = 205) underwent valve reconstruction; No-Valve Group (n = 207) received standard repair. Patients were followed for 1 year with echocardiographic assessments. Outcomes included right ventricular insufficiency, ventilation duration, and ICU stay.
Results:
Atrial Valve Group had lower right ventricular insufficiency at 12 months (9.3% vs. 19.8%, p = 0.004, OR = 2.39, 95% CI: 1.32–4.33), shorter ventilation times (6.1 vs. 18.0 hours, p < 0.001, Cohen’s d = 3.54), and reduced ICU stays (3.0 vs. 5.7 days, p < 0.001, Cohen’s d = 1.87), despite longer CPB durations (47.1 vs. 40.5 minutes, p = 0.02).
Conclusions:
Right atrial tissue reconstruction reduces early and intermediate-term right ventricular dysfunction post-tetralogy of Fallot repair. Long-term studies are needed.
Between 1980 and 2020, more than 120 countries—Canada included—enfranchised emigrants. While the diffusion of democratic practices is a well-established international phenomenon, we know little about the domestic process. How does international policy diffusion influence domestic debate? To explain the structure of Canadian debate about emigrant voting rights, we draw on concepts from the constructivist literature on international norms. In examining the structure of normative discourse within a domestic context, we argue that emulation involves three rhetorical elements that can generate disagreement: (1) setting peer countries to emulate; (2) identifying existing policy positions; and (3) envisioning the preferred policy position vis-à-vis peers. We find that in the Canadian debate about emigrant voting, contestation increased over time; where only peer groups were contested in the early debates leading up to the initial 1993 enfranchisement, all three elements were contested when discussing the removal of temporal restrictions two decades later.
Cheese-whey is a valuable byproduct of the dairy industry, rich in various nutritional components such as minerals, lactose, and proteins. Whey proteins, often used in concentrate form, are widely applied in the food industry due to their diverse chemical, physical, and techno-functional properties. This study aimed to investigate the physicochemical composition and biochemical characteristics of camel and bovine whey after partial demineralization at a laboratory scale. Camel whey exhibited lower pH values compared to bovine whey, while showing comparable levels of total solids, ash, and lactose, but significantly higher protein content. Analysis of both types of whey, before and after dialysis filtration, demonstrated partial demineralization, a significant reduction in lactose content, and a decrease in β-lactoglobulin levels in bovine whey. These findings suggest that demineralized camel and bovine whey hold significant potential for applications in the agricultural and food industries.
Bringing one’s authentic self to work is important to employees’ psychological well-being and performance. Although literature has examined how organizational factors influence authentic self-expression, it has largely overlooked the role of leaders. Drawing from leadership research, this study investigates the impact of perceived leader concern on authentic self-expression and its downstream effects on job attitudes. Findings provide empirical support for our predictions. Specifically, perceived leader concern is positively associated with authentic self-expression, which in turn relates positively to perceived self-concept-job fit. Regarding downstream outcomes, self-concept-job fit is positively related to organizational commitment and negatively to turnover intentions. Serial mediation analyses show that leader concern indirectly affects commitment and turnover intentions through authentic self-expression and self-concept-job fit. These findings highlight that leaders who show genuine concern foster open communication and authentic self-expression, enhancing alignment between identity and work, thereby strengthening commitment and reducing turnover. Implications for practice and future research are discussed.
While the impact of the two world wars and other inter-state conflicts on the history of humanitarianism has been a major area of research for some time now, comparatively little work has been done on the question of how internal wars impacted on the ways in which transnational actors and institutions approached the issue of offering relief to populations caught up in armed conflicts. Through seven articles and a thematic introduction, this collection covers conflicts that occurred in the years 1917–1949 when Europe experienced a remarkable spike in civil war violence, from Russia to Spain, and from Ireland to Greece. Collectively, these articles offer a fresh analysis of the connections between civil wars and the evolution of modern humanitarianism during Europe’s mid-twentieth-century crisis, highlighting transnational connections between humanitarian practices and actors across several conflicts.
Panpsychists commonly hang onto the ‘realist’ assumption that our world with its structures has an observer-independent, often spatial element to it, even while they claim that those structures are realized by the experiences of subjects. I argue that this assumption is the ‘worm in the apple’ that lurks behind two of panpsychism’s major problems: the subject (de)combination problem and what I call the ‘inner-outer gap problem’. Abandoning this assumption sidesteps those problems, but commits panpsychism to anti-realism.