While adapting to future sea-level rise (SLR) and its hazards and impacts is a multidisciplinary challenge, the interaction of scientists across different research fields, and with practitioners, is limited. To stimulate collaboration and develop a common research agenda, a workshop held in June 2024 gathered 22 scientists and policymakers working in the Netherlands. Participants discussed the interacting uncertainties across three different research fields: sea-level projections, hazards and impacts, and adaptation. Here, we present our view on the most important uncertainties within each field and the feasibility of managing and reducing those uncertainties. We find that enhanced collaboration is urgently needed to prioritize uncertainty reductions, manage expectations and increase the relevance of science to adaptation planning. Furthermore, we argue that in the coming decades, significant uncertainties will remain or newly arise in each research field and that rapidly accelerating SLR will remain a possibility. Therefore, we recommend investigating the extent to which early warning systems can help policymakers as a tool to make timely decisions under remaining uncertainties, in both the Netherlands and other coastal areas. Crucially, this will require viewing SLR, its hazards and impacts, and adaptation as a whole.

We provide an assessment of the Infinity Two fusion pilot plant (FPP) baseline plasma physics design. Infinity Two is a four-field period, aspect ratio $A = 10$, quasi-isodynamic stellarator with improved confinement appealing to a max-$J$ approach, elevated plasma density and high magnetic fields ($ \langle B\rangle = 9$ T). Here $J$ denotes the second adiabatic invariant. At the envisioned operating point ($800$ MW deuterium-tritium (DT) fusion), the configuration has robust magnetic surfaces based on magnetohydrodynamic (MHD) equilibrium calculations and is stable to both local and global MHD instabilities. The configuration has excellent confinement properties with small neoclassical transport and low bootstrap current ($|I_{bootstrap}| \sim 2$ kA). Calculations of collisional alpha-particle confinement in a DT FPP scenario show small energy losses to the first wall (${\lt}1.5 \,\%$) and stable energetic particle/Alfvén eigenmodes at high ion density. Low turbulent transport is produced using a combination of density profile control consistent with pellet fueling and reduced stiffness to turbulent transport via three-dimensional shaping. Transport simulations with the T3D-GX-SFINCS code suite with self-consistent turbulent and neoclassical transport predict that the DT fusion power$P_{{fus}}=800$ MW operating point is attainable with high fusion gain ($Q=40$) at volume-averaged electron densities $n_e\approx 2 \times 10^{20}$ m$^{-3}$, below the Sudo density limit. Additional transport calculations show that an ignited ($Q=\infty$) solution is available at slightly higher density ($2.2 \times 10^{20}$ m$^{-3}$) with $P_{{fus}}=1.5$ GW. The magnetic configuration is defined by a magnetic coil set with sufficient room for an island divertor, shielding and blanket solutions with tritium breeding ratios (TBR) above unity. An optimistic estimate for the gas-cooled solid breeder designed helium-cooled pebble bed is TBR $\sim 1.3$. Infinity Two satisfies the physics requirements of a stellarator fusion pilot plant.

In this work, we present a detailed assessment of fusion-born alpha-particle confinement, their wall loads and stability of Alfvén eigenmodes driven by these energetic particles in the Infinity Two Fusion Pilot Plant baseline plasma design, a four-field-period quasi-isodynamic stellarator to operate in deuterium–tritium fusion conditions. Using the Monte Carlo codes, SIMPLE, ASCOT5 and KORC-T, we study the collisionless and collisional dynamics of guiding-centre and full-orbit alpha-particles in the core plasma. We find that core energy losses to the wall are less than 4 %. Our simulations shows that peak power loads on the wall of this configuration are approximately 2.5 MW m-$^2$ and are spatially localised, toroidally and poloidaly, in the vicinity of x-points of the magnetic island chain $n/m = 4/5$ outside the plasma volume. Also, an exploratory analysis using various simplified walls shows that shaping and distance of the wall from the plasma volume can help reduce peak power loads. Our stability assessment of Alfvén eigenmodes using the STELLGAP and FAR3d codes shows the absence of unstable modes driven by alpha-particles in Infinity Two due to the relatively low alpha-particle beta at the envisioned 800 MW operating scenario.

Transport characteristics and predicted confinement are shown for the Infinity Two fusion pilot plant baseline plasma physics design, a high field stellarator concept developed using modern optimization techniques. Transport predictions are made using high-fidelity nonlinear gyrokinetic turbulence simulations along with drift kinetic neoclassical simulations. A pellet-fuelled scenario is proposed that enables supporting an edge density gradient to substantially reduce ion temperature gradient turbulence. Trapped electron mode turbulence is minimized through the quasi-isodynamic configuration that has been optimized with maximum-J. A baseline operating point with deuterium–tritium fusion power of $P_{{fus,DT}}=800$ MW with high fusion gain $Q_{{fus}}=40$ is demonstrated, respecting the Sudo density limit and magnetohydrodynamic stability limits. Additional higher power operating points are also predicted, including a fully ignited ($Q_{{fus}}=\infty$) case with $P_{{fus,DT}}=1.5$ GW. Pellet ablation calculations indicate it is plausible to fuel and sustain the desired density profile. Impurity transport calculations indicate that turbulent fluxes dominate neoclassical fluxes deep into the core, and it is predicted that impurity peaking will be smaller than assumed in the transport simulations. A path to access the large radiation fraction needed to satisfy exhaust requirements while sustaining core performance is also discussed.

The magnetohydrodynamic (MHD) equilibrium and stability properties of the Infinity Two fusion pilot plant baseline plasma physics design are presented. The configuration is a four-field period, aspect ratio $A = 10$ quasi-isodynamic stellarator optimised for excellent confinement at elevated density and high magnetic field $B = 9\,T$. Magnetic surfaces exist in the plasma core in vacuum and retain good equilibrium surface integrity from vacuum to an operational $\beta = 1.6 \,\%$, the ratio of the volume average of the plasma and magnetic pressures, corresponding to $800\ \textrm{MW}$ deuterium–tritium fusion operation. Neoclassical calculations show that a self-consistent bootstrap current of the order of ${\sim} 1\ \textrm{kA}$ slightly increases the rotational transform profile by less than 0.001. The configuration has a magnetic well across its entire radius. From vacuum to the operating point, the configuration exhibits good ballooning stability characteristics, exhibits good Mercier stability across most of its minor radius and it is stable against global low-n MHD instabilities up to $\beta = 3.2\,\%$.

We investigate convection in a thin cylindrical gas layer with an imposed flux at the bottom and a fixed temperature along the side, using a combination of direct numerical simulations and laboratory experiments. The experimental approach allows us to extend by two orders of magnitude the explored range in terms of flux Rayleigh number. We identify a scaling law governing the root-mean-square horizontal velocity and explain it through a dimensional analysis based on heat transport in the turbulent regime. Using particle image velocimetry, we experimentally confirm, for the most turbulent regimes, the presence of a drifting persistent pattern consisting of radial branches, as identified by Rein et al. (2023, J. Fluid Mech. 977, A26). We characterise the angular drift frequency and azimuthal wavenumber of this pattern as functions of the Rayleigh number. The system exhibits a wide distribution of heat flux across various time scales, with the longest fluctuations attributed to the branch pattern and the shortest to turbulent fluctuations. Consequently, the branch pattern must be considered to better forecast important wall heat flux fluctuations, a result of great relevance in the context of nuclear safety, the initial motivation for our study.

In 1926, an official delegation of prominent Muslim scholars from the Soviet Union visited Mecca. The delegation came to the holy city just a few months after the Soviet Union had become the first country to recognize the rule of ʿAbd al-ʿAziz ʿAbd al-Rahman al Saʿud (1875–1936; Ibn Saʿud) over the Hijaz. The delegation’s members attended an international Muslim congress, met with Saudi officials, and performed the hajj. Before departing they issued a statement supporting Saudi sovereignty, noting that Ibn Saʿud had “purified the [Islamic] holy lands” from the rule of the Hashemite dynasty (r. 1916–24), the Saudis’ predecessors. The Saudi state warmly welcomed this Soviet support, publishing the delegation’s statement in Umm al-Qura (est. 1924), their official weekly.1

In our target article, we proposed that curiosity and creativity are both manifestations of the same novelty-seeking process. We received 29 commentaries from diverse disciplines that add insights to our initial proposal. These commentaries ultimately expanded and supplemented our model. Here we draw attention to five central practical and theoretical issues that were raised by the commentators: (1) The complex construct of novelty and associated concepts; (2) the underlying subsystems and possible mechanisms; (3) the different pathways and subtypes of curiosity and creativity; (4) creativity and curiosity “in the wild”; (5) the possible link(s) between creativity and curiosity.

We present new stable oxygen and carbon isotope composite records (δ18O, δ13C) of speleothems from Sandkraal Cave 1 (SK1) on the South African south coast for the time interval between 104 and 18 ka (with a hiatus between 48 and 41 ka). Statistical comparisons using kernel-based correlation analyses and semblance analyses based on continuous wavelet transforms inform the relationships of the new speleothem records to other proxies and their changes through time. Between 105 and ~70 ka, changes of speleothem δ18O values at SK1 are likely related to rainfall seasonality. Variations of δ13C values are associated with changes of vegetation density, prior carbonate precipitation (PCP), CO2 degassing in the cave, and possibly variations of the abundance of C3 and C4 grasses in the vegetation. The relationships of δ18O with other proxies shift between ~70 and 48 ka (Marine Isotope Stages 4–3) so that both stable isotope records now reflect CO2 degassing, evaporation, and PCP. Similar relationships also continue after the hiatus for the deposition phase between 42 and 18 ka. Our findings support modeling results suggesting drier conditions in the study area when the Southern Hemisphere westerlies are shifted north and the paleo–Agulhas Plain is exposed.

The Upper Palaeolithic Revolution, sometimes called ‘the Creative Explosion’, is seen as the period when the forefathers of modern forager societies emerged. Similarly to the Industrial and Neolithic Revolutions, it represents a short time span when numerous inventions appeared and cultural changes occurred. The inventions were in the domain of technology, that is, shaping of new stone tool forms, longdistance exchange of raw materials, the use of bone, antler and ivory as well as rare minerals for the production of domestic and ritual objects. Spatial analysis of ‘living floors’ indicates the presence of a kitchen area, sleeping grounds, storage facilities (in certain regions) and a discard zone. We can also detect a certain increase in social hierarchy and the presence of shamans. Body decorations indicate the appearance of personal individuality. Several hypotheses were offered as an explanation for the initiation of all these cultural changes often grouped under the term ‘modern behaviour’. It stands to reason that attributing the new successful technologies observed in the Eurasian Upper Palaeolithic to intrinsic social processes and economic innovations by local Middle Palaeolithic populations would need a better archaeological demonstration than that available today. For the time being, the emergence of Modern humans in sub-Saharan Africa, their socio-economic dynamism that caused their expansion through the Nile Valley into the Near East, and their migration along the ‘southern route’ of Asia as far as Australia, is the most plausible scenario though it still leaves much to be desired from future archaeological research.

Motivated by nuclear safety issues, we study the heat transfers in a thin cylindrical fluid layer with imposed fluxes at the bottom and top surfaces (not necessarily equal) and a fixed temperature on the sides. We combine direct numerical simulations and a theoretical approach to derive scaling laws for the mean temperature and for the temperature difference between the top and bottom of the system. We find two asymptotic scaling laws depending on the flux ratio between the upper and lower boundaries. The first one is controlled by heat transfer to the side, for which we recover scaling laws characteristic of natural convection (Batchelor, Q. Appl. Maths, vol. 12, 1954, pp. 209–233). The second one is driven by vertical heat transfers analogous to Rayleigh–Bénard convection (Grossmann & Lohse, J. Fluid Mech., vol. 407, 2000, pp. 27–56). We show that the system is inherently inhomogeneous, and that the heat transfer results from a superposition of both asymptotic regimes. Keeping in mind nuclear safety models, we also derive a one-dimensional model of the radial temperature profile based on a detailed analysis of the flow structure, hence providing a way to relate this profile to the imposed boundary conditions.

Occupation of Mitzpe Shivta in the Negev Desert coincided with times of economic and social upheaval and counterculture movements during the sixth and seventh centuries AD. Inscriptions and symbols found in rock-hewn rooms in the region indicate that while the agricultural economy declined during the late Byzantine period, pilgrimage and monasticism prospered.

Between the end of World War I and the Mecca World Muslim Congress of 1926, Soviet officials and Indian Muslim thinkers imagined the possibilities of a post-imperial world through the Hijaz. The All-India Khilafat Committee (AIKC; established 1919), an organization led by prominent Indian Muslim thinkers, and the Soviet Union promoted competing projects to protect the Hijaz, home to some of Islam’s holiest shrines, against European imperialism. Yet, far from limiting themselves to the question of who should rule the Hijaz, the AIKC and the Soviet state engaged in broader debates about religious and social difference, sovereignty, and minority rights. Whereas the AIKC imagined the Hijaz as an international Muslim republic and a place of refuge for Muslims worldwide, Soviet officials contended that the political future of Muslims should only be settled within the framework of ethno-territorial nation-states. Ironically, the programs of both the AIKC and the Soviet state denied the right of self-determination to Hijazis themselves, leaving the region’s inhabitants to choose between two forms of external oversight: a Soviet-supported Saudi ethno-territorialism or limited domestic autonomy under the management and inspection of an international Muslim Council. With very few exceptions, past scholarship on the Hijaz in this period has analyzed the region’s political fortunes through Saudi statecraft or European colonial influence. However, Soviet and Indian Muslim experimental engagement with the Hijaz ultimately proved just as crucial to the consolidation of Saudi governance over the region. The article arrives at these novel insights by bringing rare Soviet archival documents together with the Urdu proceedings of the AIKC’s delegation to the Hijaz, as well as Arabic sources from the period in question.

Past and present cultures perceive their natural landscape as an integral and vital component of their complex worlds, while particular landscape features and associated monuments built in selected locales become sacred and revered through stories, legends and rituals embedded in mundane and ceremonial events. The hyper-arid Har Tzuriaz area in the southern Negev, Israel, offers a case study of culture-geographic continuities over a chronologically cumulative archaeological sequence. The large set of well-preserved structures located adjacent to water sources, a massive escarpment and a major desert crossroads includes campsites, cult sites, rock-art sites, cairn fields and one desert kite (a large game trap). Cultural continuities and change can be traced from the sixth millennium bce through recent times, reflecting a dynamic system of meanings and interpretations of both the natural and the built landscape within one particular sacred area in the desert. These phenomena are exemplified in archaeological analyses of an open-air shrine, burial cairns, an isolated desert kite and a precise engraving of that kite dated 5000 years later, all in the general context of a dense concentration of surveyed sites.