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This article examines the Qhapaq Ñan Project in Peru and its unprecedented mobilization of heritage policymaking to foster a participatory approach. The World Heritage listing of the Qhapaq Ñan, or Inca road system, catalyzed a new ethos in the Peruvian cultural heritage sector, reflected in a cohesive set of values and practices centered on community participation. This study analyzes the crafting of a participatory approach within Peruvian national heritage regulations despite legal, technical, and ideological constraints, following the rationales and processes that challenged traditional material-centered paradigms. It focuses on how heritage specialists reimagined their ethical commitments in conceptualizing and implementing this framework. It further demonstrates how participatory practices intersect with official regulations and informal practices within pre-existing technical and normative structures, integrating elements such as benefits, consultation, and collaboration. Therefore, the adoption of the Qhapaq Ñan’s participatory approach is argued not merely as a passive compliance with intergovernmental policy recommendations but as an active assertion of ethical perspectives and practices by heritage specialists.
This work investigates heat transport in rotating internally heated convection, for a horizontally periodic fluid between parallel plates under no-slip and isothermal boundary conditions. The main results are the proof of lower bounds on the mean temperature, $\overline {{\langle {T} \rangle }}$, and the heat flux out of the bottom boundary, ${\mathcal {F}}_B$, at infinite Prandtl number, where the Prandtl number is the non-dimensional ratio of viscous to thermal diffusion. The lower bounds are functions of the Rayleigh number quantifying the ratio of internal heating to diffusion and the Ekman number, $E$, which quantifies the ratio of viscous diffusion to rotation. We utilise two different estimates on the vertical velocity, $w$, one pointwise in the domain (Yan, J. Math. Phys., vol. 45(7), 2004, pp. 2718–2743) and the other an integral estimate over the domain (Constantin et al., Phys. D: Non. Phen., vol. 125, 1999, pp. 275–284), resulting in bounds valid for different regions of buoyancy-to-rotation dominated convection. Furthermore, we demonstrate that similar to rotating Rayleigh–Bénard convection, for small $E$, the critical Rayleigh number for the onset of convection asymptotically scales as $E^{-4/3}$.
The challenging tracking control issue for a space manipulator subject to parametric uncertainty and unknown disturbance is addressed in this paper. An observer-based fixed-time terminal sliding mode control methodology is put forward. Firstly, a nonlinear disturbance observer is introduced for exactly reconstructing the lumped uncertainty without requiring any prior knowledge of the lumped uncertainty. Meanwhile, the estimation time’s upper bound is not only irrelevant to the initial estimation error but can be directly predicted in advance via a specific parameter in the observer. Invoking the estimated information, a fast fixed-time tracking controller with strong robustness is designed, where a novel sliding mode surface incorporated enables faster convergence. The globally fixed-time stability of the closed-loop tracking system is rigorously demonstrated through Lyapunov stability analysis. Finally, numerical simulations and comparisons verify the validity and superiority of the suggested controller.
The problem of axisymmetric supersonic laminar flow separation over a compression corner has not been considered within the framework of triple-deck theory for several decades, despite significant advances in both theoretical methods and numerical techniques. In this study, we revisit the problem considered by Gittler & Kluwick (J. Fluid Mech., vol. 179, 1987, pp. 469–487), using the numerical method of Ruban (Zhurnal Vychislitel'noi Matematiki i Matematicheskoi Fiziki, vol. 18, issue 5, 1978, pp. 1253–1265) and Cassel et al. (J. Fluid Mech., vol. 300, 1995, pp. 265–285), termed the Ruban–Cassel method (RCM). The solution shows good agreement with the results of Gittler & Kluwick (J. Fluid Mech., vol. 179, 1987, pp. 469–487) for a scale external radius of 1 and scale angles from 1 to 6. However, for scale angles above 6.8, a wave packet appears. This wave packet is similar to that reported by Cassel et al. (J. Fluid Mech., vol. 300, 1995, pp. 265–285) for two-dimensional supersonic flow. As the external scale radius increases (from 1 to 10), the axisymmetric solution converges towards the two-dimensional solution for equivalent scale angle values. For a scale external radius of 10, the wave packet appears at a scale angle of 3.8, compared with the value of 3.9 by Cassel et al. (J. Fluid Mech., vol. 300, 1995, pp. 265–285). Inspection of the velocity profiles reveals that inflection points, while ubiquitous in shear flow, do not seem to play a relevant role in the appearance of the wave packet for the axisymmetric flow. Axisymmetric effects become more important as the scale external radius decreases below 0.5. A larger scale angle is necessary to produce a flow structure equivalent to that of the two-dimensional case. For scale external radius 0.1, the pressure gradient is substantially diminished and the solution is devoid of a second shear-stress minimum.
This paper explores the ‘puzzle of the nomads’ in the Metaphysics of Morals: the apparent tension between Kant’s argument about the duty to leave the state of nature and his insistence that European colonizers cannot permissibly force nomads to enter a civil union. Arguing that the puzzle is twofold, I suggest that the answer lies in the relationship between the state and territory in Kant’s work. After showing the shortcomings of an approach which suggests that nomadic peoples cannot enter the civil state without settling, I defend an alternative interpretation, which conceives the territoriality of the state as contingent.
We investigate two findings in Gali and Monacelli (2016, American Economic Review): (i) the effectiveness of labor cost adjustments on employment is much smaller in a currency union and (ii) an increase in wage flexibility often reduces welfare, more likely in an economy that is part of a currency union. First, we introduce a distorted steady state into Gali and Monacelli’s small open economy model, in which employment subsidies making the steady state efficient are not available, and replicate their two findings. Second, an endogenous fiscal policy rule similar to that in Bohn (1998, Quarterly Journal of Economics) is introduced with a government budget constraint in the model. The results suggest that while Gali and Monacelli’s first finding is still applicable, their second finding is not necessarily valid. Therefore, an increase in wage flexibility may reduce welfare loss in an economy that is part of a currency union as long as wage rigidity is sufficiently high. Thus, there is scope to discuss how wage flexibility benefits currency unions.
This paper introduces a method to realize beam switching by using a substrate-integrated waveguide (SIW) Butler matrix combined with a slot array antenna. The Butler matrix consists of two hybrid couplers, two crossovers, two −45-degree phase shifters, and two 0-degree phase shifters. The slot array antenna is a 4 × 2 array. The operating frequency band of the slot array antenna, where the reflection coefficient is below −10 dB, is 26.5–31.5 GHz. The measured beamforming angles from input port 1 to input Port 4 of the Butler matrix are +46, −16, +15, and −50°, respectively. The corresponding antenna gains from input Port 1 to input Port 4 are 11.57 dB, 14.284 dB, 10.94 dB, and 12.864 dB, respectively. The dimensions of the Butler matrix and the slot array antenna are 56.8 mm × 21.2 mm × 0.254 mm. The dimensions of the SIW transmission channels between the Butler matrix and input Ports 1– 4 are 16.9 mm × 34 mm × 0.254 mm.
Active flow control based on reinforcement learning has received much attention in recent years. Indeed, the requirement for substantial data for trial-and-error in reinforcement learning policies has posed a significant impediment to their practical application, which also serves as a limiting factor in the training of cross-case agents. This study proposes an in-context active flow control policy learning framework grounded in reinforcement learning data. A transformer-based policy improvement operator is set up to model the process of reinforcement learning as a causal sequence and autoregressively give actions with sufficiently long context on new unseen cases. In flow separation problems, this framework demonstrates the capability to successfully learn and apply efficient flow control strategies across various airfoil configurations. Compared with general reinforcement learning, this learning mode without the need for updating the network parameter has even higher efficiency. This study presents an effective novel technique in using a single transformer model to address the flow separation active flow control problem on different airfoils. Additionally, the study provides an innovative demonstration of incorporating reinforcement-learning-based flow control with aerodynamic shape optimization, leading to collective enhancement in performance. This method efficiently lessens the training burden of the new flow control policy during shape optimization, and opens up a promising avenue for interdisciplinary intelligent co-design of future vehicles.
In 1820 two French scientists – Pierre Joseph Pelletier and Jean Bienaimé Caventou – discovered and named the active alkaloid substance extracted from cinchona bark: quinine. The bark from the ‘wondrous’ fever tree, and its antimalarial properties, however, had long been known to both colonial scientists and indigenous Peruvians. From the mid-seventeenth century, cinchona bark, taken from trees that grow on the eastern slopes of the Andes, was part of a global circulation of botanical knowledge, practice and profit. By the 1850s, Europeans eager to bypass South American trade routes to access cinchona plants established plantations across the global South in French Algeria, Dutch Java and British India. Wardian cases – plant terrariums named after British physician Nathaniel Bagshaw Ward – would fuel new imperial efforts to curb malaria, contemporaries argued. And yet cinchona trees proved difficult to transport over land and sea, and did not easily or universally thrive in new tropical climates. As a result of the growing demand and uncertainty around cinchona, as Pratik Chakrabarti has argued, from the late eighteenth century there was ‘a global scientific obsession’ with finding a ‘substitute’ for cinchona, particularly local alternatives in India and China.1
In sub-Saharan Africa, and particularly within Ghana’s savanna ecosystem, scientific studies on the distribution patterns and habitat use of raptors, including vultures, are scarce. Despite global research on vulture abundance and habitat preferences, data from West Africa remain limited. This study examines the abundance of four vulture species, focusing on their seasonal activity, age distribution, and preference for three specific habitats, i.e. woodlands, riparian forests, and grasslands, in the southern part of Mole National Park (MNP), Ghana. We conducted a survey using 39 line transects during both dry and wet seasons to make an inventory of these species. Employing a generalised linear model, we assessed the influence of seasons, age, and habitat types on vulture abundance. Our survey recorded a total of 466 vultures, with Hooded Vulture Necrosyrtes monachus and White-backed Vulture Gyps africanus being the most frequently observed. Vulture numbers were notably higher in riparian and woodland areas than in grasslands, and adults were more prevalent than juveniles across all observed species. The study highlights the need for continuous monitoring and the protection of critical riparian habitats to aid in the conservation of these threatened species within the MNP.
Reduced exposure to sweet taste has been proposed to reduce sweet food preferences and intakes, but the evidence to support these associations is limited. This randomised controlled trial investigated the effects of a whole-diet sweet taste intervention for 6 d, on subsequent pleasantness, desire for and sweet food intakes. Participants (n 104) were randomised to increase (n 40), decrease (n 43) or make no change to (n 21) their consumption of sweet-tasting foods and beverages for 6 consecutive days. Pleasantness, desire to eat, sweet taste intensity and sweet food and beverage intakes were assessed on days 0 and 7. One hundred and two (98 %) participants completed the study, and self-reported adherence with the dietary interventions was moderate to good (M = 66–72/100 mm), with instructions to decrease sweet food consumption reported as more difficult than the other diets (smallest (t(81) = 2·45, P = 0·02, Mdiff = 14/100 mm, se = 2 mm). In intention-to-treat analyses, participants in the decreased sweet food consumption group reported higher sweet taste intensity perceptions at day 7 compared with day 0 (F(2101) = 4·10, P = 0·02, Mdiff = 6/100 mm, se = 2 mm). No effects were found for pleasantness (F(2101) = 2·04, P = 0·14), desire to eat (F(2101) = 1·49, P = 0·23) or any of the measures of sweet food intake (largest F(2101) = 2·53, P = 0·09). These results were confirmed in regression analyses that took self-reported adherence to the diets into account. Our findings suggest that exposure to sweet taste does not affect pleasantness, desire for or intakes of sweet-tasting foods and beverages. Public health recommendations to limit the consumption of sweet-tasting foods and beverages to reduce sweet food preferences may require revision.
Recent years have witnessed growing attention to popular culture’s role in the reproduction, negotiation, and contestation of global political life. This article extends this work by focusing on games targeted at young children as a neglected, yet rich site in which global politics is constituted. Drawing specifically on the Heroes of History card game in the Top Trumps franchise, I offer three original contributions. First, I demonstrate how children’s games contribute to the everyday (re)production of international relations through the contingent storying of global politics. Heroes of History’s narrative, visual organisation, and gameplay mechanics, I argue, construct world politics as an unchanging realm of conflict through their shared reproduction of a valorised, masculinised figure of the warrior hero. This construction, moreover, does important political work in insulating young players from the realities and generative structures of violence. Second, the polysemy of children’s games means they also provide opportunity for counter-hegemonic ‘readings’ of the world even in seemingly straightforward examples of the genre such as this. Third, engaging with such games as meaningful objects of analysis opens important new space for dialogue across International Relations literatures on children, popular culture, gender, the everyday, and heroism in world politics.
This article examines the effects of the militarization of public security and the conflicts it triggers on a central democratic institution: press freedom. We focus on Mexico, which experienced multiple waves of assassinations of local journalists after the federal government declared a War on Drugs against the country’s main cartels and deployed the military to the country’s most conflictive regions. We argue that violence against journalists is tied to the outbreak of criminal wars—the multiple localized turf wars and power struggles unleashed by the federal military intervention. Subnational politicians and their security forces and drug lords are at the center of these conflicts because they jointly enable local operations of the transnational drug-trafficking industry. To defend their interests, they have individual and shared incentives to prevent city- and town-level journalists from (or punish them for) publishing fine-grained information that may compromise their criminal and political survival and their quest for local control. We compiled the most comprehensive dataset available on lethal attacks on journalists from 1994 to 2019 to test our claims. Using a difference-in-differences design, we show that violence against local journalists substantially increased in militarized regions, where the military decapitated the cartels and fragmented the criminal underworld, triggering violent competition for criminal governance—de facto rule over territories, people, and illicit economies. Evidence from original focus groups and interviews with at-risk reporters suggests that governors, mayors, and their police forces possibly joined cartels in murdering journalists to mitigate the risks of unwanted information and to minimize the costs of criminal governance by silencing the press and society. Our study offers a sobering lesson of how the militarization of anti-crime policy and the onset of criminal wars can undermine local journalism, press freedom, and democracy.
Owing to habitat loss, the entire breeding population of the globally threatened Aquatic Warbler Acrocephalus paludicola, a flagship bird species of fen mires, is now limited to scattered areas in east-central Europe. The breeding biology of the Aquatic Warbler was studied between 2012 and 2015 in calcareous fens dominated by the Cladietum marisci sedge community at the south-western range limit of the species, near Chełm, in south-east Poland. Two nesting peaks were observed during the breeding season, corresponding to first and second breeding attempts. Nest densities were greater during the first- rather than the second-brood period but singing male densities did not differ between the brood periods. Clutch size and post-hatching fledging success were significantly lower during the second-brood period. Total nest fledging success (whether or not a nest fledged at least one young) was 76.6% in 124 nests with known outcomes with an average of 2.7 (± SE 0.2) fledglings per nest. Mayfield probability of nest survival was 56.9% with losses mainly due to predation (55%), nest desertion or female predation (28%), and changes in water level (14%). Nest survival to fledging increased along the gradient of increasing levels of litter layer thickness, stagnating water, and vegetation height at the nest, and increasing height of the nest above the soil. Fledgling production tended to be lower than in the Biebrza Marshes (north-east Poland) habitats, assumed to be optimal for breeding. Otherwise, the reproductive success estimates did not deviate from nests found in the core breeding areas in north-east Poland or Belarus. Brood feeding frequency (15.5 ± 1.0/hour) was similar to that observed in the Biebrza Marshes. Our results suggest that the calcareous fens at the margins of the current species’ range provide a suitable breeding habitat. However, as the nesting area has contracted, management programmes tailored to the ecological requirements of the Aquatic Warbler are required.