Royal Society Open Science最新文献

The sonochemical method is a novel synthesis route that takes advantage of the use of ultrasonic radiation to obtain different nanomaterials with an improvement in the process variables and material characteristics. In this work, two different synthesis routes to obtain a double perovskite structure were compared in detail. The Pechini synthesis method is a widely used and effective way to obtain this kind of structure by the formation of a cross-linked network of metal cations. Alternatively, in sonochemistry, chemical reactions occur with the application of powerful ultrasound radiation. The final characteristics of synthesized powders of La_0.9Sr_0.1Fe_0.9Co_0.1O_{3± δ} (LSFC) were analysed thermally, structurally, morphologically and optically, and their transport properties were evaluated to determine their semiconductor character in a solid oxide fuel cell device and in photocatalytic processes. Structural results indicated a well crystallized perovskite structure with a single cubic phase. The cell parameter a (approx. 3.89 Å) and crystal size measurements (11-20 nm) were determined by Rietveld refinement for samples obtained by both synthesis methods. Thescanning electron microscope micrographs showed aggregates with homogeneous morphology and a uniform particle size distribution, with a rough and porous surface. Optical properties were determined by ultraviolet-visible spectrophotometry and photoluminescence, resulting in an E _g of 1.2 and 0.8 eV in samples from Pechini and sonochemistry, respectively.

When losing balance, upper-body movements serve as mechanical aids to regain stability. However, it remains unclear how these movements contribute to dynamic stability during recovery from a lateral loss of balance while walking with arm restriction. We aimed to (i) quantify the effect of arm restriction on gait stability and upper-body velocities and (ii) characterize upper-body kinematic strategies in response to lateral surface translations under different arm restriction conditions. Healthy adults were exposed to lateral surface translations while walking on a computerized treadmill under three conditions: 'free arms', '1-arm restricted' and '2-arms restricted'. Dynamic stability and upper-body velocities for the first step after perturbation onset were extracted. We found decreased dynamic stability in the sagittal plane and increased trunk velocity in the '2-arms restricted' condition compared with the 'free arms' condition. Head and trunk movements in the medio-lateral plane were in opposite directions in 44.31% of responses. Additionally, significant trunk velocities were observed in the opposite direction to the perturbation-induced loss of balance. Our results support the contribution of increased upper-body velocities to balance responses following arm-restricted walking perturbations and suggest that the '2-arms restricted' condition may be utilized as a perturbation-based balance training, focusing on head and trunk responses.

Electricity competition, restrictions on carbon dioxide (CO2) emissions and arm races between nations are examples of social dilemmas within human society. In the presence of social dilemmas, rational choice in game theory leads to the avoidance of cooperative behaviour owing to its cost. However, in experiments using public goods games that simulate social dilemmas, humans have often exhibited cooperative behaviour that deviates from individual rationality. Despite extensive research, the alignment between human cooperative behaviour and game theory predictions remains inconsistent. This study proposes an alternative approach to solve this problem. We used Q-learning, a form of artificial intelligence that mimics decision-making processes of humans who do not possess the rationality assumed in game theory. This study explores the potential for cooperation by varying the number of participants in public goods games using deep Q-learning. The simulations demonstrate that agents with Q-learning can acquire cooperative behaviour similar to that of humans. Moreover, we found that cooperation is more likely to occur as the group size increases. These results support and reinforce existing experiments involving humans. In addition, they have potential applications for creating cooperation without sanctions.

Mito-nuclear discordances across secondary contact zones have been described in a wide range of organisms. They consist of a spatial mismatch between nuclear and mitochondrial genomes in terms of location and extension of the contact zone between distinct evolutionary lineages. Despite the evolutionary and biogeographic causes of mito-nuclear discordances having been extensively investigated, we still lack a clear understanding of their phenotypic underpinnings. Here, we test the hypothesis that mtDNA variation could be associated with behavioural variation and that such association could contribute to asymmetric mitochondrial introgression across a secondary contact zone. We analysed behavioural variation across the mtDNA secondary contact zone of the fire salamander Salamandra salamandra in central Italy, which is displaced 600 km from the nuclear contact zone. We found distinct behavioural profiles in the two mitotypes co-occurring in the contact zone. The introgressed mitotype was associated with a 'slow-thorough' dispersal profile, characterized by a less active but more cautious and accurate exploration strategy. This pattern was consistent across life stages and contexts: aquatic larvae and terrestrial juveniles, spontaneous activity and response to novelty. These results support the intriguing hypothesis that personality traits associated with distinct mitotypes could contribute to differential mitochondrial introgression and the formation of biogeographic patterns of mito-nuclear discordance.

Diverse information encoding systems, including human language, the vocal and gestural systems of non-human animals and the structure of DNA and proteins, have been found to conform to 'Menzerath's Law'-a negative relationship between the number of units composing a sequence, and the size of those units. Here, we test for the presence of Menzerath's Law in the vocal bouts produced in a submissive context by meerkats (Suricata suricatta). Using a suite of Bayesian mixed effects models, we examined 1676 vocal bouts produced by 89 wild meerkats, ranging from 1 to 590 calls in length, to determine whether the number of calls composing each bout had a negative relationship with the duration of those calls or their inter-call intervals. In contradiction to Menzerath's Law, we found that the duration of vocalizations had a positive relationship with the number of calls in a bout. However, the duration of intervals between calls did have a negative relationship with bout size. Moreover, both calls and intervals had longer durations the closer they were positioned to the end of the bout. These findings highlight the multi-faceted ways in which efficiency trade-offs can occur in the vocal repertoires of non-human animals, shaping variability in the production of signal forms.

Insect societies, which are at a high risk of disease outbreaks, have evolved sanitary strategies that contribute to their social immunity. Here, we investigated in the red ant Myrmica rubra, how the discarding of nestmate cadavers is socially organized depending on the associated pathogenicity. We examined whether necrophoresis is carried out by a specific functional group of workers or by any nestmates that may become short-term specialists. By observing the behavioural profiles of tagged individuals, we assigned half of the colony members to functional groups (foragers, intermittent-foragers, domestics, nurses and inactives). Following the introduction of uninfected or sporulating corpses into the nest, intermittent-foragers were the functional group most involved in necrophoresis, as they touched, moved and discarded more cadavers. Interestingly, sporulating corpses induced a more generalized response in workers from all functional groups, thereby accelerating their rejection from the nest. The individuals contacting corpses were also prophylactically engaged in more grooming behaviour, suggesting the existence of hygienist workers within ant colonies. These findings raise questions about a trade-off existing between concentrating health risks on a few workers who are highly specialized in necrophoresis and exposing a larger population of nestmates who cooperate to speed up nest sanitization.

Developing efficient foraging strategies is critical for survival, especially during the high-mortality post-fledging period in birds. This period is particularly challenging for migratory species, where juveniles must navigate unfamiliar environments with limited experience and knowledge. Our study focused on the foraging strategies of 20 juvenile lesser black-backed gulls (Larus fuscus) during the first 20 days of their initial migratory stopover. We assessed learning through changes in their spatial (re)use and activity patterns using GPS tracking data, in direct comparison with similar data collected from 38 experienced adults. Juveniles were less exploratory and spent more time foraging than adults, but showed similar spatial consistency. Over time, both juveniles and adults reduced their range distribution areas, but only adults significantly reduced their flying time. Adults exhibited space use optimization by travelling shorter distances and spending progressively more time foraging. In contrast, juveniles showed no clear evidence of spatial learning or improved foraging skills, as there was no decrease in cumulative distance travelled nor a clear pattern in time spent foraging.

[This corrects the article DOI: 10.1098/rsos.241311.].

As the first group of tetrapods to achieve powered flight, pterosaurs first appeared in the Late Triassic. They proliferated globally, and by the Late Jurassic through the Cretaceous, the majority of these taxa belonged to the clade Monofenestrata (which includes the well-known Pterodactyloidea as its major subclade), typified by their single undivided fenestra anterior to the orbit. Here, a new taxon Melkamter pateko gen. et sp. nov., represented by the specimen MPEF-PV 11530 (comprising a partial cranium and associated postcranial elements), is reported from the latest Early Jurassic (Toarcian) locality of Queso Rallado (Cañadón Asfalto Formation) and referred to the clade Monofenestrata, increasing our previously known taxonomic and geographic representations, and temporal range for this clade. This occurrence marks the oldest record of Monofenestrata globally and helps to shed critical light on the evolutionary processes undergone during the 'non-pterodactyloid'-to-pterodactyloid transition within the Pterosauria. In addition, another single isolated tooth from the same locality shows ctenochasmatid affinities. These finds further elucidate the still-poor Gondwanan Jurassic pterosaur fossil record, underscoring that most of our current ideas about the timing and modes of pterosaur evolution during that period are largely based on (and biased by) the pterosaur fossil record of the Northern Hemisphere.

Artificial reefs for coral reef restoration are often concrete-based. After concrete is poured, it initially has a high surface pH (approx. 13), which neutralizes within several weeks. During this curing, colonization by marine microalgae is delayed and also macrobenthos such as corals may be impacted. In this study, we evaluated how concrete curing time applied prior to the deployment of artificial reefs affected coral performance. Fragments of five coral species were outplanted onto ordinary Portland concrete discs (n = 10) that had been cured on land. Seven different curing periods were applied, ranging from one day up to four months. The discs with corals were deployed at a Kenyan reef and photographed at the start and end of the experiment. After 1 year, coral cover had increased for four coral species and declined for one, but this was unrelated to concrete curing time. Also, no effect of curing time was seen on the development of other common benthic organisms such as macroalgae or soft corals. We conclude that curing of concrete is unlikely to have any long-term negative impacts on coral performance and therefore, extended curing of artificial reefs prior to coral attachment is unlikely to benefit reef restoration efforts.