In this article we trace a biography of vacuum aspiration in Spain between the 1960s and 1980s. Analysing the local but transnationally connected history of vacuum aspiration during late Francoism and the democratic transition, we argue that this technology was since the mid-1960s reincarnated in mainstream medical discourse as vacuum curettage, presented as a major medical innovation in diagnosis and therapy. While abortion activists working at the end of the 1970s emphasized the group and political components of a technique they called the ‘Karman method’, doctors performing illegal abortions within the family planning network defined vacuum aspiration in terms of safety and medical innovation. As we demonstrate, this technique embodied meanings that at times overlapped, at others conflicted, contingent on whether aspirations were linked to medical innovation, pro-abortion activism, or social justice.

The present work investigates the thermochemical non-equilibrium effect in the DLR combustor using a two-temperature model combined with vibration-chemistry coupling model. Two operating conditions with inflow Mach 2 and 6 are selected for study. The simulation results illustrate that translational-vibrational non-equilibrium is related to energy transfer behaviour and the translational-vibrational relaxation time. When kinetic energy and chemical energy are converted into internal energy, there is a significant difference in the degree of conversion to translational and vibrational energy. If the translational-vibrational relaxation time is larger than the flow time, such as the relaxation time of the mainstream aftershock wave is 0.25 s for the condition with inflow Mach 2, and the flow time is 3 × 10−5 s, non-equilibrium will occur. Significant differences exist between the flow fields with Mach 2 and 6. A clear boundary layer separation occurs at Mach 6. Combustion occurs at the shear layer, which is in translational-vibrational equilibrium, and there are varying degrees of non-equilibrium in other locations. The dissociation of N2 and production of NO primarily occur on the strut walls and the upper/lower walls of the combustor. The mass fraction of NO is higher than the value at Mach 2. The combustion performance is influenced by the thermochemical non-equilibrium effect. At the condition of Mach 2, it increases the combustion efficiency by 10% near the injector and 0.27% at outlet relatively. Non-equilibrium inhibits the initial upstream combustion while slightly promoting downstream combustion under inflow Mach 6 condition.

A recent fluorescence of geophysical and archaeological research in Catholic cemeteries illustrates the benefits and challenges of community-engaged projects. Focusing on four ongoing case studies in coastal Virginia and Maryland (the Chesapeake region)—St. Mary’s Basilica (Norfolk, Virginia); Brent Cemetery (Stafford County, Virginia); Sacred Heart Church (Prince George’s County, Maryland); and St. Nicholas Cemetery (St. Mary’s County, Maryland)—this article explores a variety of archaeological strategies in the context of community engagement. These approaches are shaped by the physical characteristics of cemetery sites, the Catholic diocesan or church communities that oversee them, and the African American descendant communities affected by them. The built environment of cemeteries highlights the way that racism and segregation have shaped both the landscape and public memory of Catholic cemeteries in the Chesapeake region.

Soft robots have emerged as a transformative technology with widespread applications across diverse fields. Among various actuation mechanisms, fluid-based actuation remains predominant in soft robotics, where precise fluid regulation is fundamental to system performance. This review aims to provide a comprehensive reference for researchers interested in fluid regulation strategies in soft robots by outlining the current state of research in this field and discussing innovations in valve designs to inspire future advancements. The fluid regulation strategies discussed in this review are systematically categorized into three main approaches: valve-based, smart fluid-based, and pressure source-based strategies, with each type systematically classified and discussed in detail. Building upon this analysis, a Task-to-Fluidic Regulation System mapping framework is proposed, integrating the V-model principles from systems engineering to provide a structured, requirements-driven methodology that links task objectives to concrete regulation system configurations through sequential design and multi-level verification. Finally, the latest advancements in fluid regulation methods in soft robotics are summarized, along with emerging trends and directions for future development.

This article explores how water conditions in geographical contexts could influence the construction of teachers’ professional identities and, consequently, their knowledge and beliefs about water sustainability. Water sustainability is defined as the responsible management of water from a perspective that integrates environmental, social and economic sustainability principles. This quantitative study employed an ad hoc questionnaire, inspired by the New Water Culture principles as a conceptual sustainability framework. The instrument, designed with Google Forms, was administered to 221 secondary school teachers from two cities with contrasting water and cultural conditions: Bogotá (Colombia) and Melilla (Spain). Results indicate that teachers’ knowledge and beliefs in both cities are not aligned with water sustainability principles, with no significant differences between the two groups due to their different water conditions. However, there are partial differences related to the respective personal experiences: in Bogotá, teachers show greater concern for water quality, whereas in Melilla the focus is more on the quantity available. These findings underline the importance of promoting teachers’ professional development in water sustainability aligned with professional identities, as a key strategy for nurturing aware and engaged citizens. This approach is fundamental to tackle water stress challenges and foster a paradigm shift towards more responsible, sustainable lifestyles globally.

The variable stiffness actuator (VSA) excels at tasks that are challenging for traditional rigid mechanisms to perform. A novel variable stiffness tensegrity-based compliant actuator is proposed, following an analysis of the cons and pros of existing VSAs. The proposed actuator leverages a tensegrity structure to eliminate direct contact between rigid elements, thereby reducing the internal mechanical friction. This leads to low damping and compliant behavior. Additionally, it enables a wide range of stiffness adjustments and decouples rotational stiffness from the rotation angle by utilizing different variants of the mechanically adjustable compliance and controllable equilibrium position actuator (MACCEPA). The stiffness analysis of the single-joint actuator is presented and experimentally validated. This design is then extended to multi-joint mechanism applications, including serial mechanism configuration, wire-driven mechanism configuration, and direct-drive mechanism configuration. An evaluation of the structural characteristics of these three configurations is provided, offering different options for implementing VSAs. The conducted works could provide fresh insights into the field of VSA.

This article explores innovation in the chamber music that the internationally acclaimed composer Tan Dun (b. 1957) composed during the early 1980s, particularly his integration of traditional Chinese music elements with modern Western composition techniques. A detailed analysis of a representative selection of these early chamber music works focuses on Tan Dun’s pursuit of cultural symbols within a contemporary musical landscape. The findings highlight Tan Dun’s use of musical features such as microtones, aleatoric elements and special playing techniques to evoke traditional Chinese cultural traces in his compositions. The article also discusses his approach to polyphonic construction, which not only continues the horizontal melodic axis of Chinese music, but also creates rich vertical textures.

This article attempts to map some of Vietnam’s national identities that were constructed in the early twentieth century (1900s-1930s). Instead of treating Vietnamese national identity either as a monolithic entity or as too fragmented to be considered a useful concept, it shows that at least three interactive and overlapping national identities emerged, each with its own political significance and state institutionalisation. To map them, this article re-traces several key nationalists in the early twentieth century. It situates each of their national imaginations within interconnected global relations, namely, Civilisational relations of hierarchy, cultural relations of equality, and radical relations of exploitation and oppression. This analytical approach to mapping national identity offers a framework that may prove valuable for cross-national comparative studies.

The smallest eigenvalue of a graph is the smallest eigenvalue of its adjacency matrix. We show that the family of graphs with smallest eigenvalue at least $-\lambda $ can be defined by a finite set of forbidden induced subgraphs if and only if $\lambda < \lambda ^*$, where $\lambda ^* = \rho ^{1/2} + \rho ^{-1/2} \approx 2.01980$, and $\rho $ is the unique real root of $x^3 = x + 1$. This resolves a question raised by Bussemaker and Neumaier. As a byproduct, we find all the limit points of smallest eigenvalues of graphs, supplementing Hoffman’s work on those limit points in $[-2, \infty )$.

We also prove that the same conclusion about forbidden subgraph characterization holds for signed graphs. Our impetus for the study of signed graphs is to determine the maximum cardinality of a spherical two-distance set with two fixed angles (one acute and one obtuse) in high dimensions. Denote by $N_{\alpha , \beta }(d)$ the maximum number of unit vectors in $\mathbb {R}^d$ where all pairwise inner products lie in $\{\alpha , \beta \}$ with $-1 \le \beta < 0 \le \alpha < 1$. Very recently Jiang, Tidor, Yao, Zhang, and Zhao determined the limit of $N_{\alpha , \beta }(d)/d$ as $d\to \infty $ when $\alpha + 2\beta < 0$ or $(1-\alpha )/(\alpha -\beta ) \in \{1,\sqrt 2,\sqrt 3\}$, and they proposed a conjecture on the limit in terms of eigenvalue multiplicities of signed graphs. We establish their conjecture whenever $(1-\alpha )/(\alpha - \beta ) < \lambda ^*$.