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We investigate experimentally the effect of salinity and atmospheric humidity on the drainage and lifetime of thin liquid films motivated by conditions relevant to air–sea exchanges. We show that the drainage is independent of humidity and that the effect of a change in salinity is reflected only through the associated change in viscosity. On the other hand, film lifetime displays a strong dependence on humidity, with more than a tenfold increase between low and high humidities: from a few seconds to tens of minutes. Mixing the air surrounding the film also has a very important effect on lifetime, modifying its distribution and reducing the mean lifetime of the film. From estimations of the evaporation rate, we are able to derive scaling laws that describe well the evolution of lifetime with a change of humidity. Observations of the black film, close to the top where the film ruptures, reveal that this region is very sensitive to local humidity conditions.
Noise source identification has been a long-standing challenge for decades. Although it is known that sound sources are closely related to flow structures, the underlying physical mechanisms remain controversial. This study develops a sound source identification method based on longitudinal and transverse process decomposition (LTD). Large-eddy simulations were performed on the flow around a cylinder at a Reynolds number of 3900. Using the new LTD method, sound sources in the cylinder flow were identified, and the mechanisms linking flow structures with noise generation were discussed in detail. Identifying the physical sound sources from two levels, low-order theory and high-order theory, the physical mechanism of wall sound sources was also analysed. Results indicate that the sound sources in the flow field mainly come from the leading edge, shear layer and wake region of the cylinder. The high-order theory reveals that sound sources are correlated with the spatio-temporal evolution of enstrophy, vortex stretching and surface deformation processes, this reflecting the coupling between transversal and longitudinal flow fields. The boundary thermodynamic flux and boundary dilatation flux distribution of the cylinder were analysed. Results indicate that the wall sound sources mainly come from the separation point and have a disorderly distribution on the leeward side of the cylinder, which is the main region where longitudinal variables enter the fluid from the wall surface, and the wall sound source is related to the boundary enstrophy flux.
With over 2,500 climate-related cases filed worldwide, climate litigation is rapidly evolving but lacks a comprehensive resource for guiding judicial approaches. The Cambridge Handbook on Climate Litigation fills this void, offering an authoritative guide to climate litigation's complex landscape. Judges, lawyers and scholars will find insights into how courts globally have addressed recurring issues, from causation to human rights impacts. Building on the rich transnational judicial dialogue already occurring within climate litigation, the Handbook distills emerging best practices with an eye towards the progressive development of the field. Its unique focus on replicable strategies in case law makes it a strategic resource for shaping the future of climate litigation. This title is also available as open access on Cambridge Core.
The pebble crab, Leucisca levigena, was recorded for the first time from the intertidal regions of South Andaman in the Andaman and Nicobar Islands, India. This comes after its holotype was described in 1976 from Western Australia. The species was found on the thallus of the green seaweed, Halimeda opuntia. Notably, the study included the first record of a male specimen, previously absent in its first description. L. levigena is characterized by its slightly concave dorsal carapace with a beaded margin, a raised gastric region extending to the front, and a smooth pterygostomial region. A brief description and illustrations of both the male and female species and a map showing the distribution of Leucisca species around the world are provided. L. levigena confirms its distribution from Western Australia to the Andaman Islands.
The recovery of nearly 250 burials at the El Olivar site provided the opportunity to address questions regarding the groups inhabited coastal settings of the semiarid north of Chile between the 800 and 1540 AD. Stable isotopes of carbon, nitrogen, and oxygen were analyzed from 60 human samples. Radiocarbon (14C) analyses were conducted in 20 samples from camelids and 42 human samples. Subsequently, a sample of 25 individuals exhibiting diagnostic cultural features of the Las Ánimas Cultural Complex (LACC) and the Chilean Diaguita Culture (CDC) was selected for the purpose of assessing differences in their diet and mobility and clarifying their chronology. The δ13C and δ15N values obtained revealed the existence of a small group of individuals (n=6) with a diet based on C3 plants and terrestrial protein, and another major group (n=33) with values compatible with the consumption of C4 plants and marine resources. Four of the six individuals of the small group presented Ánimas diagnostic features, and in the major group were identified both Ánimas and Diaguita individuals. The δ18O values exhibited a similarity between the Ánimas and Diaguita individuals, suggesting coastal-to-inland mobility in both groups. Calibrated 14C dates indicate that El Olivar was occupied for a period of nearly 380 years, spanning between 1150 and 1536 AD, and that between the 1300 and 1400 AD, Ánimas and Diaguita individuals coexisted at El Olivar. These findings call into question the current thought that the CDC emerged from the LACC around 1000 AD, and that both represent different archaeological entities.
Saltmarshes are widely recognized as one of the most productive coastal habitats, and on the Amazon coast, Spartina alterniflora marshes are widespread on both marine and freshwater sites. On the Amazon coast, this ecosystem is subject to a wide array of environmental factors that influence its characteristics and associated macrobenthic fauna. However, few studies have been carried out in Amazonian saltmarshes when compared to others regions worldwide. Therefore, this study characterizes the vertical distribution of macrobenthic fauna in Amazon saltmarshes and their seasonal changes. Vertical stratified samples (0–10 and 10–20 cm) were collected during the rainy (April 2008) and dry seasons (November 2008) in saltmarshes located in an Environmental Protected Area located on the Northern Brazilian Amazon coast (Algodoal-Maiandeua island). The saltmarsh area varied between seasons, being denser and taller in the dry season. A total of 38 macrobenthic taxa were recorded, of which 11 were exclusively found in the dry season. The macrobenthic faunal structure varies among seasons, with higher density and richness in the dry season. Overall, higher densities and richness were found at near-surface layers in both seasons. We suggest that the vertical distribution of the macrobenthic fauna depend on the vegetation density in Amazon saltmarshes, since this vertical distribution is more prominent in the dry season where we observed higher Spartina density and most of the fauna is concentrated near the surface. Therefore, this study provides novel insights into macrobenthic distribution patterns, reinforcing that Amazonian saltmarshes have unique characteristics that strongly influence their distribution.
Numerous studies showed that the flow and transport phenomena in angstrom channels are different from existing understandings. In this work, we investigate the electrokinetic phenomena in a charged angstrom channel, including homogeneous and heterogeneous charge distributions at the wall to mimic the charging mechanisms of electrified metal-like surfaces and deprotonated dielectric surfaces, respectively. Our results show that both the streaming current and the flow velocity linearly increase as the applied pressure increases in a homogeneously charged system. However, in a heterogeneously charged system, the streaming current is activated only when the applied pressure exceeds a critical threshold. This behaviour arises from the strong Coulomb interactions between counterions and the surface charge, manifesting as an obvious nonlinear feature. The dissociation of counterions from the surface charge may not only cause pressure-dependent streaming conductance but also reduce the friction coefficient of the system, thus the flow resistance, when the system friction is governed by the bound ions. We found that such pressure-dependent streaming conductance gradually weakens as the channel size increases and reaches the regime of classical nanofluidic theories. Taking one-dimensional non-equilibrium statistics and Markov chains for the sequence evolution of bound-ion dissociation, our theory can well explain the pressure-dependent streaming conductance and water permeability in angstrom charged channels. Voltage-driven nonlinear ionic transport and electro-osmosis were also observed in heterogeneously charged systems. Our findings will be helpful for understanding the ionic transport in angstrom-scale channels and possibly useful in ion separations.
Genome size (GS) is thought to be a key life-history trait and important for controlling plant distributions and evolutionary dynamics, but a full understanding of GS variation through evolutionary history requires proxy measurements from fossils. Here, we compare two potential GS proxies: guard cell length (GCL) and sporomorph size. We generated GCL and pollen size data from angiosperms growing in the University of Münster Botanical Garden, compiled sporomorph size data from the literature, and related these to GS using phylogenetic regression models. We also fit evolutionary models to the botanical garden data and used a published dataset to validate GCL as a GS proxy. The majority of the analyses conducted revealed a positive relationship between GS and sporomorph size, but in most cases, the explanatory power of the regressions was low. GCL showed a stronger and more consistent relationship with GS, and independent validation of the relationship showed a generally good match between predicted and observed GS. Sporomorph size is not suitable as a cross-taxon GS proxy, but some specific taxa (e.g., Pinus) may contain useful GS information. GCL has much more potential for measuring paleo-GS, but requires further research for us to better understand possible environmental controls on cell size variation.
Four new hemipteran insects are described from the Triassic (Norian) Cow Branch Formation of Virginia and North Carolina (USA), including one pair of isolated wings belonging to Hylicellidae (Hylicelloidea: Cicadomorpha), one complete specimen assigned to a distinctive new genus of Ipsviciidae (Scytinopteroidea: Cicadomorpha), and two heteropterans belonging to unknown families. Only the ipsviciid is preserved with enough morphological detail for systematic study and is herein described as Solitivicia reducta new genus new species due to its highly reduced forewing venation. The peculiar distribution of hemipterans in the Cow Branch Formation, namely the paucity of cicadomorphans and coleorrhynchans which are both otherwise abundant in Triassic deposits, is discussed.
The new damselfly family Shundeagrionidae is proposed for Shundeagrion cheni n. gen. n. sp. from the Paleocene of the Sanshui Basin, South China. This new family is unique in a combination of wing venation characters that are separately encountered in other extant and fossil groups. Together with the extinct groups Dysagrionidae, Sieblosiidae, Whetwhetaksidae, Menatlestidae, Latibasaliidae, Euarchistigmatinae, and Eodysagrioninae, the Shundeagrionidae n. fam. is the eighth major group of Paleogene damselflies with large wings, very long postnodal area, and nodus relatively basally recessed. It confirms that an important diversification occurred worldwide among the damselflies during the Paleocene and Eocene. These relatively ancient groups were progressively replaced by the modern families of large calopterygoid damselflies during the Oligocene and the Miocene, leading to the modern faunas.
A previous study of the altitudes of the lowest part of the Upper Cretaceous–Eocene stratigraphic ensemble evidenced for the first time the existence of an east-west elongated dome between N53° and N54° Lat. on the western slope of the Southern Urals. This ridge which is superimposed on the remnants of the Sernovodsk–Abdullino Aulacogen and with the Belaya tear fault was the result of the rejuvenation of these deep basement features; it has been interpreted as a positive flower structure. Slightly to the north, the Southern Urals display a clear bend towards the East. In front of it, detailed microstructural studies show that this curvature was associated with a stress pattern typical of an indentation. Field studies concentrating on the intersection between the flower structure and the Belaya River Valley show (1) that there are two riverbeds more or less superimposed in the same valley, (2) that the older watercourse is offset by small east-west shear zones, (3) that the shear zones are in continuity with the flower structure and (4) that the recent riverbed is not affected by similar offsets. The vertical movements recorded along the Belaya River by geodetic measurements don’t support the existence of a recent activity of the indenter because they are always of a limited extent and associated with karst collapses. This conclusion is supported by the stratigraphic evolution of the fluvial sediments and confirms that the indentation of the Southern Urals did not continue after 10 ka.
Pterotheca Salter, 1853 is an unusual but readily identifiable bellerophontoid gastropod that occurs in the Upper Ordovician to the Llandovery of the lower Silurian in many parts of North America and Europe. Recently, a large collection of Pterotheca was obtained for the first time from the Xiushan Formation of middle Telychian (Llandovery) age in the Hunan Province of South China. This is also the first record of the genus in the low-latitude peri-Gondwanan region. On the basis of the collection, two new species of Pterotheca—P. yongshunensis and P. xiushanensis—were identified and are described herein. The morphologic analysis suggests that close relatives of these new species may be Pterotheca species from the Telychian of Scotland. The new species show continuous variations of marginal apex to submarginal apex, implying that one of the Pterotheca species may be ancestral to the Devonian Aspidotheca Spriesterbach, 1919. The Pterotheca species from South China possibly lived a slowly crawling life on a soft substrate, feeding on algae and/or detritus, and were adapted to a shallow-water setting with substantial terrigenous input. Given that all the known Silurian Pterotheca species occurred in siliciclastic settings, most of which represent sea-level fall and lowstand periods, we demonstrate that geographic isolation and enhanced ocean circulation during the early Silurian regression facilitated the speciation of Pterotheca globally, and the connection of a sea pathway during the Rhuddanian transgression after the end-Ordovician glaciation could have led to the primary dispersal of Silurian Pterotheca.
The rapid advancement of large language models (LLMs) has enabled their integration into a wide range of scientific disciplines. This article introduces a comprehensive benchmark dataset specifically designed for testing recent LLMs in the hydrology domain. Leveraging a collection of research articles and hydrology textbooks, we generated a wide array of hydrology-specific questions in various formats, including true/false, multiple-choice, open-ended, and fill-in-the-blank. These questions serve as a robust foundation for evaluating the performance of state-of-the-art LLMs, including GPT-4o-mini, Llama3:8B, and Llama3.1:70B, in addressing domain-specific queries. Our evaluation framework employs accuracy metrics for objective question types and cosine similarity measures for subjective responses, ensuring a thorough assessment of the models’ proficiency in understanding and responding to hydrological content. The results underscore both the capabilities and limitations of artificial intelligence (AI)-driven tools within this specialized field, providing valuable insights for future research and the development of educational resources. By introducing HydroLLM-Benchmark, this study contributes a vital resource to the growing body of work on domain-specific AI applications, demonstrating the potential of LLMs to support complex, field-specific tasks in hydrology.
Specimens of Tulaneia amabilia Runnegar and Horodyski n. gen n. sp. (previously Ernietta plateauensis Pflug) discovered by RJH in 1991 at a site in the Montgomery Mountains near Johnnie, Nevada, are described for the first time. All of the material from the original locality was from float, but its stratigraphic position within the lowest siliciclastic to dolostone interval of the lower member of the Wood Canyon Formation (LMWCF) was confirmed by subsequent discoveries. Because the upper part of the LMWCF contains Treptichnus pedum (Seilacher), the Ediacaran–Cambrian boundary has long been drawn at its first appearance. However, in the Esmeralda Member of the Deep Spring Formation in the White-Inyo Mountains, California, and at Mount Dunfee, Nevada, another Cambrian ichnofossil, ‘Plagiogmus’, which is now Psammichnites gigas arcuatus (Roedel), is found just beneath the nadir of the basal Cambrian isotope excursion (BACE). Because the nadir of the BACE excursion is older than ca. 539 Ma in Mexico, the oldest occurrences of Treptichnus pedum in the LMWCF are latest—not earliest—Fortunian in age, and there is no need to reduce the age of the eon boundary from ca. 539 to ca. 533 Ma. Tulaneia resembles Ernietta and other erniettomorphs in being composed of tubular modules with planar common surfaces, but its overall shape was tabular and unidirectional rather than sack or frond shaped. We also illustrate and briefly describe other trace and body fossils from the LMWCF and re-illustrate previously published specimens of Psammichnites gigas arcuatus in order to document its earliest occurrence in the Great Basin.
Embedding the intrinsic symmetry of a flow system in training its machine learning algorithms has become a significant trend in the recent surge of their application in fluid mechanics. This paper leverages the geometric symmetry of a four-roll mill (FRM) to enhance its training efficiency. Stabilising and precisely controlling droplet trajectories in an FRM is challenging due to the unstable nature of the extensional flow with a saddle point. Extending the work of Vona & Lauga (Phys. Rev. E, vol. 104(5), 2021, p. 055108), this study applies deep reinforcement learning (DRL) to effectively guide a displaced droplet to the centre of the FRM. Through direct numerical simulations, we explore the applicability of DRL in controlling FRM flow with moderate inertial effects, i.e. Reynolds number $\sim \mathcal{O}(1)$, a nonlinear regime previously unexplored. The FRM’s geometric symmetry allows control policies trained in one of the eight sub-quadrants to be extended to the entire domain, reducing training costs. Our results indicate that the DRL-based control method can successfully guide a displaced droplet to the target centre with robust performance across various starting positions, even from substantially far distances. The work also highlights potential directions for future research, particularly focusing on efficiently addressing the delay effects in flow response caused by inertia. This study presents new advances in controlling droplet trajectories in more nonlinear and complex situations, with potential applications to other nonlinear flows. The geometric symmetry used in this cutting-edge reinforcement learning approach can also be applied to other control methods.
This paper presents the results of accelerator mass spectrometry radiocarbon (AMS 14C) dating performed on archaeological samples (human bone, wood charcoal, and other charred plant macro-remains) from six sites located in the Lesser Poland Upland (southern Poland). We report 41 14C age measurements performed on discoveries made during the contract excavations carried out during the S7 roadway construction from 2016–2022. The resulting ages fall into a long interval, which, in terms of the regional archaeological periodization, lasts from the Late Neolithic to the Late Antiquity/Early Medieval Period (ca. 4600 BC–600 AD), and in terms of the climatological periodization corresponds to the Atlantic, Subboreal, and Subatlantic.