The brazilwood tree Paubrasilia echinata is endemic to the Atlantic Forest of Brazil and is categorized as Endangered on the IUCN Red List as a result of habitat loss and overexploitation. Phylogenomic analysis has identified five groups based on genotype, including the arruda-RJ lineage endemic to the state of Rio de Janeiro. We propose a prioritization classification protocol for Atlantic Forest fragments and evaluate the effectiveness of conservation for this species in Rio de Janeiro. We collated a total of 164 occurrence records of P. echinata from fieldwork during 2004–2024 and from the Global Biodiversity Information Facility. We classified forest fragments containing the species as high, medium or low priority for conservation. The arruda-RJ lineage persists in 43 forest fragments in the coastal region, 30 of which are documented for the first time here. Most forest fragments are small and have an uneven population structure. Urbanization is the primary threat to the survival of this lineage. We documented protected areas in 33 fragments, and identified conservation opportunities. The greatest number of forest fragments is in the northern region where there are the most protected areas and the brazilwood populations hold the greatest local genetic diversity. We propose targeted conservation actions for P. echinata arruda-RJ in eight forest fragments identified as high priority and with the greatest potential for conservation of the lineage. We identified 25 fragments as medium priority and 10 fragments as low priority. Our approach is applicable to other lineages of P. echinata and is aligned with Global Biodiversity Framework targets.

Poor public service provision creates an electoral vulnerability for incumbent politicians. Under what conditions can bureaucrats exploit this to avoid reforms they dislike? We develop a model of electoral politics in which a politician must decide whether to enact a reform of uncertain value, and a voter evaluates the incumbent’s reform based on post-reform government service quality, which anti-reform bureaucrats can undermine. Bureaucratic resistance for political leverage is most likely to occur when voters are torn between the reform and the status quo. Resistance lowers the informational value of government service for voters and can lead to policy distortions and accountability loss. When reform is moderately popular, resistance leads to policy inefficiency by preventing beneficial reforms due to electoral risks and inducing ineffective reforms by offering bureaucrats as scapegoats. Our model identifies a distinct mechanism of bureaucratic power and its implications for policy and accountability.

To enhance the aerodynamic performance of hypersonic nozzles, a three-dimensional method of characteristics (3D MOC) is proposed for designing single expansion ramp nozzles (SERN). The flowfield structures and aerodynamic performances of nozzles designed using the 3D and conventional two-dimensional (2D) MOC approaches are compared through three-dimensional numerical simulations. Results indicate that the major geometric differences occur along the circumferential wall. Under typical flight conditions, the nozzle designed by 3D MOC achieves over 0.45% higher axial thrust coefficient and more than 8% higher lift coefficient than the 2D MOC design. Furthermore, based on the 3D MOC, both rectangular nozzle (RN) and circular nozzle (CN) configurations are designed and analysed. The CN exhibits slightly superior aerodynamic performance compared with the RN. By further modifying the upper and lower wall infill surfaces of the RN, three new nozzle variants are obtained. Comparative results show that these geometric infills have a pronounced influence on lift and pitching moment, while the axial thrust coefficient remains nearly constant. Finally, the effect of the tracing radius on the RN and CN configurations is examined. Increasing the tracing radius notably reduces the lift coefficient but has minimal impact on the thrust and pitching moment. These findings highlight the potential of the 3D MOC-based design method to flexibly balance aerodynamic moment and lift in hypersonic nozzle optimisation.

In many areas in linguistic study it is difficult to decide where the study of language ends and the study of other aspects of human cognition begins. In this article, we discuss a particularly striking case of this, the use of the signing space (loci) for marking linguistic relations. The use of loci in the nominal and verbal domains has received a wide range of analyses, from those considering loci to be abstract linguistic mechanisms such as semantic indices and syntactic agreement to those considering them to be making use of nonlinguistic mechanisms such as spatial cognition. We defend the view that the use of loci is both fundamentally linguistic (they are modifiers) and fundamentally spatial (they express an association with space), providing possible descriptive content in both the verbal and the nominal domain. This analysis allows for a uniform account of loci use in the two linguistic domains and accounts for an important, yet less noticed, property of loci, which is that their distribution is pragmatically conditioned for the purpose of disambiguation.

We perform analytical and numerical analyses of the propulsion of a rigid body in a viscous fluid subjected to a periodic force with zero average over a period. This general formulation specifically addresses the significant case where propulsion is generated by the oscillation of a mass located in an internal cavity of the body. We provide a rigorous proof of the necessary and sufficient conditions for propulsion at the second order of magnitude of the force. These conditions are implemented and confirmed by numerical tests for bodies without fore-and-aft symmetry, while they are silent for bodies with such symmetry, like round ellipsoids. Consequently, in this case, propulsion can only occur at an order higher than the second. This problem is investigated by numerically integrating the entire set of equations, and the result shows that, in fact, propulsion does occur, thus opening new avenues for further analytical studies.