Demographic change is one of Germany’s most pressing social and economic challenges. Using data from a representative telephone survey, we analyze how well informed respondents are about the magnitude of demographic change and what factors influence the accuracy of their beliefs. We find that respondents tend to overestimate the old-age dependency ratio when considering the current and long-term demographic situation separately. However, their beliefs regarding the change of the old-age dependency ratios over the considered period are not far from the projected change. A better understanding of the German statutory pension insurance plays an important role for more accurate beliefs.

Researchers in history and the historical sciences explore the use of generative AI (GenAI) systems for reconstructing destroyed artifacts. This paper poses a novel question: Can such GenAI systems generate evidence that provides new knowledge about the world or can they only produce hypotheses that we might seek evidence for? Exploring responses to this question, the paper argues that (1) GenAI outputs can at least be understood as higher-order evidence (Parker 2022) and (2) may also constitute de novo synthetic evidence.

This study investigates the accumulation of glycogen, amino acids, and fatty acids in male Mytilus coruscus during different stages of gonadal development and explores their relationships with reproductive processes. Glycogen levels were highest during the resting phase, decreasing progressively during the proliferation and maturation phases. A positive correlation was observed between glycogen and carbon content, indicating a close association between energy storage and metabolic processes. Amino acid content, particularly essential amino acids (EAAs), increased during gonadal development, reflecting the higher demand for protein synthesis and cellular metabolism. Branched-chain amino acids (BCAAs) such as isoleucine, leucine, and lysine were key in activating protein synthesis and supporting gametogenesis. Non-essential amino acids like aspartic acid, glutamic acid, and glycine also accumulate, supporting cellular function and reproductive regulation. Fatty acids, especially unsaturated fatty acids (UFAs) and polyunsaturated fatty acids (PUFAs), progressively accumulated in the testes, highlighting their role in energy supply and membrane integrity during gametogenesis. Phosphorus (P) accumulated in parallel with fatty acids, supporting DNA and RNA synthesis, energy metabolism, and cell membrane function. This study emphasizes the crucial role of these biochemical components in supporting gonadal development in male M. coruscus, providing insights into the metabolic pathways involved in marine bivalve reproduction.

This paper examines the gendered foundations of citizenship status among first-generation immigrants in Western Europe. It posits that foreign-born women are more likely than foreign-born men to become citizens in their new homeland if they originate from countries with greater gender inequality. Moreover, this relationship is amplified among highly educated female immigrants. In contrast, no gender gap in citizenship status exists among newcomers from origin countries with low gender inequality. The empirical analyses based on the individual-level data from the European Social Survey (ESS) 2010–22 confirm these expectations. These findings have important implications for our understanding of immigrant political integration in western democracies and the consequences of gender inequality around the world.

This paper presents four new monolithic continuum robot designs that can be 3D printed in a single piece and with TPU or similar elastic filaments for either educational or experimental applications. Similar tendon-driven continuum robots are usually made of a flexible backbone (often in NiTi alloys) and rigid vertebrae, with tens of components in a robot segment resulting in time-consuming manual assembly and high costs. Conversely, the proposed designs achieve equivalent functionality while avoiding the manufacturing challenges. Additionally, by removing the need for coupled features for assembly and 3D-printing backbones and vertebrae as a single part, new geometries are possible and can be explored to tailor robot performance to specific requirements. To validate the proposed design, four sample prototypes have been manufactured and experimentally tested. The obtained results, when compared to the piecewise constant curvature model, demonstrate a 3.06% tip positioning error and limited reduction of the workspace area of 23.07%, which compares favorably to similar but more expensive and complex tendon-driven robots.

This article presents a comprehensive analysis of the production dynamics within the Kerameikos during the major period of black- and red-figure pottery production (600–350 BCE). Employing a statistical approach, this study explores the intricate interplay between the workflows of full-time and part-time painters and potters, and the nature of their respective tasks. By using Monte Carlo methods to estimate quantities, including the number of pots created annually and the hours required for painting, the statistical data generated not only support a complex and time-critical model for the potting industry, but the limits on the plausibility for some of these scenarios are also considered. These quantitative estimates are then situated within the context of the pottery-production chaîne opératoire to consider the seasonality of the various professions of pottery production. A case is made for the existence of permanent painters managing a backlog of pottery while part-time potters shifted between potting and painting (and other tasks), while the concept of project management is also discussed; it is suggested that a critical role of the κϵραμϵύς extended beyond mere craftsmanship to orchestrating workflows.

This paper presents experimental studies on a novel active high-frequency coaxial injector system designed for enhanced flow mixing and control at extreme flow velocity conditions. The flow dynamics and mixing characteristics of the system operating at 15kHz were captured using planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV) techniques and compared against its steady and baseline modes. In pulsed mode, this active injection system delivers a pulsed supersonic actuation air jet at the inner core of the coaxial nozzle that provides large mean and fluctuating velocity profiles in the shear layers of an acetone-seeded fluid stream injected surrounding the core through an annular nozzle. The instantaneous velocity, vorticity and acetone concentration fields of the injector are discussed. The high-frequency streamwise vortices and shockwaves tailored to the mean flow significantly enhanced supersonic flow mixing between the fluids compared to a classical steady coaxial configuration operating at the same input pressure. The paper analyses the dynamic and diffusion characteristics of this active coaxial injection system, which may have potential for supersonic mixing applications.

A finite group is said to be n-cyclic if it contains n cyclic subgroups. For a finite group G, the ratio of the number of cyclic subgroups to the number of subgroups is known as the cyclicity degree of the group G and is denoted by $\textit {cdeg} (G)$. In this paper, we classify all $12$-cyclic groups. We also prove that the set of cyclicity degrees for all the finite groups is dense in $[0,1]$, which solves a problem posed by Tărnăuceanu and Tóth [‘Cyclicity degrees of finite groups’, Acta Math. Hungar. 145(2) (2015), 489–504].

Africa has the oldest artefacts and evidence for fire. It is where Homo sapiens evolved and developed novel technologies before dispersing into the rest of the world some 70ka ago. There is, however, no reliable evidence in Africa for artificial shelters and dwellings older than 20ka. This paper sets out to understand why such basic architecture appears so late in a continent with great environmental variation and a deep history of innovation. The approach combines evidence from micro and macro scales of analysis. The micro scale uses ethnoarchaeological studies of Africa’s small circular houses to examine how and why gender separates their occupants both spatially and through their access to food stores. At the macro scale, the absence of food stores among Africa’s extant hunters and gatherers is predicted from environmental factors that apply to the whole continent. Without food storage there are no significant dwellings. I then turn to the archaeological evidence for the appearance of dwellings and storage from Africa and the Levant, a contiguous region where huts are known at 23ka. The evidence for dwellings in Europe is then considered. While dwellings are earlier here than in Africa and the Levant none are reliably older than 32ka. They are found with evidence for food storage. The paper explores the implications of this chronological framework for a major transition in hominin evolution that, before agriculture, involved intensification in subsistence combined with storage, and a novel architecture of gendered spaces now found worldwide.

We prove that the proximal unit normal bundle of the subgraph of a $W^{2,n} $-function carries a natural structure of Legendrian cycle. This result is used to obtain an Alexandrov-type sphere theorem for hypersurfaces in $ \mathbf{R}^{n+1} $, which are locally graphs of arbitrary $W^{2,n} $-functions. We also extend the classical umbilicality theorem to $ W^{2,1} $-graphs, under the Lusin (N) condition for the graph map.

The eighteenth-century French slave ship the Bonne Société traded bundles of goods in exchange for slaves in Loango. We present detailed evidence from the ship’s trading log that decomposes the goods in the bundle and identifies the European and African merchants selling captives to the ship. Prices steadily increased throughout the captain’s stay in port, and the captain increased the bundle’s price by adding more goods and adding high-priced goods. Sellers participated both as one-shot traders and as repeat traders. These results add a nuanced picture of how this destructive trade worked in practice.

This article presents a highly integrated 300-GHz frequency-modulated continuous wave radar sensor using a custom-developed dual-function transceiver MMIC. The system can either be configured as a stand-alone ultra-wide-band radar sensor or as a flexible RF front-end, enabling up-conversion and down-conversion of modulated signals to and from the terahertz range. The transceiver MMIC is manufactured using a 90 nm SiGe BiCMOS process, featuring high-speed hetero-junction bipolar transistors with an $f_{\rm{T}}$ of 300 GHz and $f_{\rm{max}}$ of 520 GHz. Using on-chip antennas and a focusing lens, the EIRP of the system for radar operation is greater than 3.2 dBm in a bandwidth of 54 GHz. The full potential of the system’s 90 GHz tuning range is demonstrated in radar measurements. A calibration method is applied to expand the usable tuning range, achieving an extraordinary spatial resolution of 1.97 mm with a frequency sweep from 330 to 240 GHz in 5 ms for a target at a distance of 0.35 m. The potential industrial use of this spatial resolution is demonstrated in a plastic thickness measurement scenario. Additionally a 100 Mbd OKK communication link with a BER of 0.55% is presented using two systems at 0.3 m distance.