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Whereas many evolutionary models emphasize within-group cooperation or between-group competition in explaining human large-scale cooperation, recent work highlights a critical role for intergroup cooperation in human adaptation. Here we investigate intergroup cooperation in the domain of shotgun hunting in northern Republic of the Congo. In the Congo Basin broadly, forest foragers maintain relationships with neighboring farmers based on systems of exchange regulated by norms and institutions such as fictive kinship. In this study, we examine how relationships between Yambe farmers and BaYaka foragers support stable intergroup cooperation in the domain of shotgun hunting. In the study village, shotgun hunting is based on a specialization-based exchange wherein Yambe farmers contribute shotguns and access to markets to buy cartridges and sell meat while BaYaka foragers contribute their specialized forest knowledge and skill. To understand how costs and benefits are distributed, we conducted structured interviews with 77 BaYaka hunters and 15 Yambe gun owners and accompanied hunters on nine hunting trips. We found that hunts are organized in a conventional manner within a fictive kinship structure, consistent with the presence of intercultural mechanisms to stabilize cooperation. However, because bushmeat demand is high, gun owners can gain significant cash profit, while compensating hunters only with cigarettes, alcohol, and a traditional hunter’s portion of meat. To level payoffs, hunters strategically hide kills or cartridges from gun owners to feed their own families. Our results illustrate how each group prioritizes different currencies (e.g., cash, meat, family, intergroup relations) and provide insights into how intergroup cooperation is stabilized in this setting. The example of this long-standing intergroup cooperative system is discussed in terms of its contemporary entwinement with logging, the bushmeat trade, and growing market intersection.

A powder metallurgy-based strategy to in situ construct a three-dimensionally interconnected hexagonal boron nitride (3Di-hBN) layers surrounding the grains of Cu-Ni matrix through metal–organic chemical vapor deposition process was utilized to fabricate 3Di-hBN-reinforced Cu0.7-Ni0.3 (3Di hBN-Cu-Ni) composite. The effect of 3Di-hBN on the mechanical properties of 3Di hBN-Cu-Ni composite was assessed by comparing with pure Cu-Ni alloy (without hBN) fabricated via powder metallurgy route under similar processing conditions. Uniaxial tensile investigations showed that 3Di-hBN positively influenced the mechanical properties of 3Di hBN-Cu-Ni composite; ∼16.3, ∼11.67, and ∼27.9% higher yield strength, UTS, and fracture toughness, respectively, compared to PM Cu-Ni alloy. The overall improved performance of 3Di hBN-Cu-Ni composite was attributed to the formation of 3Di-hBN layers at the interfaces of Cu-Ni grains, which enable the composite to withstand the applied load through the mechanisms of load transfer, dislocation strengthening, and grain refinement. In addition, thermal conductivity of 3Di hBN-Cu-Ni composite was found ∼10% higher than that of pure Cu-Ni alloy.

This study compares high-temperature grain growth behavior in copper matrix composites containing nano-carbons in the form of fullerenes, carbon nanotubes (CNTs), and graphene to investigate the effect of volume fraction and shape of nano-carbon reinforcement on grain growth suppression. The grain growth was significantly suppressed when the nano-carbon content was 5 vol%, but the suppression efficiency was reduced when nano-carbon particle loading increased above 20 vol%. Furthermore, CNTs induced better grain growth suppression than fullerenes and graphene. Grain growth was observed both near the nano-carbon interfaces and in the bulk matrix. The poor wetting ability between copper and the nano-carbons accelerates lattice diffusion at the reinforcement interface. Owing to differences in the thermal expansion coefficients and elastic moduli between copper and the nano-carbons, due to the presence of the reinforcement, stress distribution will be inhomogeneous. In composites containing discontinuous reinforcement, the stress is concentrated at the tip of the reinforcement and at its minimum at the center of the reinforcement. Inhomogeneous stress fields are formed in the far away from the reinforcement, which in turn causes the suppression of overall grain growth in the composites.

Nursing mothers face an energetic trade-off between infant care and work. Under pooled energy budgets, this trade-off can be reduced by assistance in food acquisition and infant care tasks from non-maternal carers. Across cultures, children also often provide infant care. Yet the question of who helps nursing mothers during foraging has been understudied, especially the role of children. Using focal follow data from 140 subsistence expeditions by BaYaka women in the Republic of Congo, we investigated how potential support from carers increased mothers' foraging productivity. We found that the number of girls in early childhood (ages 4–7 years) in subsistence groups increased food returns of nursing women with infants (kcal collected per minute). This effect was stronger than that of other adult women, and older girls in middle childhood (ages 8–13 years) and adolescence (ages 14–19 years). Child helpers were not necessarily genetically related to nursing women. Our results suggest that it is young girls who provide infant care while nursing mothers are acquiring food—by holding, monitoring and playing with infants—and, thus, that they also contribute to the energy pool of the community during women's subsistence activities. Our study highlights the critical role of children as carers from early childhood.

The COVID-19 pandemic has been reshaping the world by accelerating non-contact services and technologies in various domains. Hospitals as a healthcare system lie at the center of the dramatic change because of their fundamental roles: medical diagnosis and treatments. Leading experts in health, science, and technologies have predicted that robotics and artificial intelligence (AI) can drive such a hospital transformation. Accordingly, several government-led projects have been developed and started toward smarter hospitals, where robots and AI replace or support healthcare personnel, particularly in the diagnosis and non-surgical treatment procedures. This article inspects the remaining element of healthcare services, i.e., surgical treatment, focusing on evaluating whether or not currently available laparoscopic surgical robotic systems are sufficiently preparing for the era of post-COVID-19 when contactless is the new normal. Challenges and future directions towards an effective, fully non-contact surgery are identified and summarized, including remote surgery assistance, domain-expansion of robotic surgery, and seamless integration with smart operating rooms, followed by emphasis on robot tranining for surgical staff.

Catalytic oxidation is a feasible method for remediating volatile organic compounds (VOCs), due to its lower energy consumption and mineralization of VOCs into H

Investigating past and present human adaptation to the Congo Basin tropical forest can shed light on how climate and ecosystem variability have shaped human evolution. Here, we first review and synthesize genetic, palaeoclimatological, linguistic and historical data on the peopling of the Congo Basin. While forest fragmentation led to the increased genetic and geographical divergence of forest foragers, these groups maintained long-distance connectivity. The eventual expansion of Bantu speakers into the Congo Basin provided new opportunities for forging inter-group links, as evidenced by linguistic shifts and historical accounts. Building from our ethnographic work in the northern Republic of the Congo, we show how these inter-group links between forest forager communities as well as trade relationships with neighbouring farmers facilitate adaptation to ecoregions through knowledge exchange. While researchers tend to emphasize forager–farmer interactions that began in the Iron Age, we argue that foragers' cultivation of relational wealth with groups across the region played a major role in the initial occupation of the Congo Basin and, consequently, in cultural evolution among the ancestors of contemporary peoples. This article is part of the theme issue ‘Tropical forests in the deep human past’.

Al-Ce based alloys have gained recent interest and have proven to have excellent strength without heat treatment and high thermal stability. Challenges with the production of Al-Ce samples from elemental powders arise due to the elemental material before alloying being susceptible to rapid oxidation. The methodology for making superconductive wire, powder-in-tube, was used as a consolidate Al and Ce elemental powder, and Al-8 wt % Ce-10 wt % Mg composite powder into bulk nanostructured material. Powder samples are fabricated in an inert controlled atmosphere, then sealed in a tube to avoid oxidation of powders. Therefore, most of the powder is used without much loss. We used 316 stainless-steel tubes as a sheathing material. For Al-xCe wt % (x = 8 to 14) samples of elemental powder, liquid phase sintering was used and for Al-Ce-Mg powder solid-state sintering. Characterization of the bulk consolidated material after sintering, and before and after heat treatment, was made using optical and Scanning Electron Microscope imaging, Energy Dispersive Spectroscopy, Microhardness and Rockwell Hardness test. We demonstrated that microstructure stability in Al-Ce-based specimens can be retained after thermomechanical processing. Densification was achieved and oxidation of powder was avoided in most samples. In addition, we found that Fe and Ni in the sheathing material react with Al in the process, and Ce concentration modifies the reactivity the sheath.

Tropical rainforests are characterized by a high diversity of plant species. Each plant species presents with differential phenological patterns in fruit production. In some species, all individual trees produce fruit simultaneously within clustered periods; whereas in others, each individual tree fruits at irregular time intervals. By observing this pattern, some primate species use the presence of fruits in one tree as a cue to find fruit in other trees of the same synchronously fruiting tree species. Here, we investigated whether the highly frugivorous Javan gibbons (Hylobates moloch) in Gunung Halimun-Salak National Park in Indonesia have knowledge of synchronous characteristics of fruiting trees and whether they can further distinguish fruit species with different synchrony levels, that is, tree species with highly synchronous fruiting patterns versus tree species with less synchronous fruiting patterns. Across 12 months we collected biweekly phenological data on 250 trees from 10 fruit species and observed Javan gibbons' visits to those species. We found that a fruit discovery in the beginning of fruiting seasons triggered gibbons to visit trees of the same fruit species. However, gibbons' visit rates did not differ between highly synchronous and asynchronous species. Our results suggest that Javan gibbons have knowledge of synchronous characteristics of fruiting trees in general, but they do not differentiate highly synchronous versus asynchronous fruit species. We speculate that Javan gibbons, who live in relatively small ranges with very low tree density of preferred fruit species, are likely able to track and remember fruiting states of individual trees without needing to distinguish fruit species with different synchrony levels. Moreover, gibbons may make little benefit of distinguishing highly synchronous versus asynchronous fruit species, probably due to gibbons' heavy use of asynchronous figs. Our study provides an insight into how gibbon's foraging strategies may have been shaped in response to their ecological environment.

Within comparative psychology, the evolution of animal cognition is typically studied either by comparing indirect measures of cognitive abilities (e.g., relative brain size) across many species or by conducting batteries of decision-making experiments among (typically) a few captive species. Here, we propose a third, complementary approach: inferring and comparing cognitive abilities through observational field records of natural information gradients and the associated variation in decision-making outcomes, using the ranging behavior of wild animals. To demonstrate the feasibility of our proposal, we present the results of a global survey assessing the availability of long-term ranging data sets from wild primates and the willingness of primatologists to share such data. We explore three ways in which such ranging data, with or without the associated behavioral and ecological data often collected by primatologists, might be used to infer and compare spatial cognition. Finally, we suggest how ecological complexity may be best incorporated into comparative analyses. Publisher PDF

When resources are limited and defensible, inter-group encounters in animals are often of aggressive nature. Individuals can participate in inter-group encounters to defend mates, infants, and food resources, but also to attract out-group individuals for additional mating opportunities. Since inter-group conflicts have mainly been studied in group-living species, we examined the mate, infant, and food resource defense and mate attraction hypotheses in pair-living Javan gibbons (Hylobates moloch) in Gunung Halimun-Salak National Park, Indonesia. To this end, we investigated factors influencing male and female participation and outcome of encounters (i.e., win vs. lose). We observed 234 complete encounters between three habituated and five unhabituated gibbon groups over 43 months, of which 72% were aggressive. Males were the main participants and they were more likely to participate when cycling females or dependent infants were present, supporting the mate and infant defense hypotheses. Males were also more likely to participate when more fruits were available, contradicting the food resource defense hypothesis. Females participated by singing more often when they were cycling and when there were singing opponents, suggesting an advertisement function of their reproductive status through songs. The probability of winning an inter-group encounter was only higher when cycling females were present, supporting the mate defense hypothesis. The intensity of space use or aggression level had no effect on the outcome of inter-group encounters. Our results highlight that mate and infant defense are crucial for male Javan gibbons, especially in view of their pair-living system, long interbirth intervals, and slow infant development. While animal groups interact aggressively with each other to defend valuable resources, they can also interact to increase additional mating opportunities. Here, we examined male and female participation and the outcomes of inter-group encounters in a wild pair-living primate, the Javan gibbon. Crucially, we found that the presence of cycling females had a significant impact on male participation, female singing, and the outcome of encounters. Our findings suggest that Javan gibbon females may advertise their reproductive status through singing during inter-group encounters while Javan gibbon males rather participate to defend their mates and infants.

In this study, copper/few-layered graphene (Cu/FLG) composite powder is prepared using two different approaches, chemical synthesis and mechanical milling, and the effect of the processing routes on the mechanical and thermal behaviors of hot-pressed pallets is examined. With both processing routes, the strength of the matrix is increased ∼3.90 and ∼2.82 times by grain refinement, and is further increased 1.14 times by incorporating 0.5 vol.% FLG. In addition, for both processing routes, the coefficient of thermal expansion is reduced from ∼17.07 to ∼15.15 (ppm/K) by incorporating 0.5 vol.% of FLG in both composites. Considering its cost-effectiveness, simplicity, and potential for mass-production, the mechanical process demonstrates the ability to produce Cu/FLG composites with a high mechanical and thermal performance that is comparable to solution-based chemical synthesis routes.

This study proposes a facile solution process to generate a reduced graphene oxide (rGO) protection layer on Al, in which polyvinyl alcohol (PVA) is used to enhance interfacial bonding between Al and rGO. A multi-level analysis indicated that PVA-aided coating induced numerous conjugations between Al and rGO by producing a large number of hydroxyl groups on the Al surface. The Al plate directly coated by rGO showed good corrosion resistance compared with the pristine Al, implying that rGO may act as an effective corrosion barrier for Al. Moreover, the Al coated by the PVA-aided process exhibited higher corrosion resistance than the directly coated Al as well as the pristine Al due to the enhanced adhesion between Al and rGO.

To understand the evolutionary roots of human spatial cognition, researchers have compared spatial abilities of humans and one of our closest living relatives, the chimpanzee (Pan troglodytes). However, how humans and chimpanzees compare in solving spatial tasks during real-world foraging is unclear to date, as measuring such spatial abilities in natural habitats is challenging. Here we compared spatial movement patterns of the Mbendjele BaYaka people and the Taï chimpanzees during their daily search for food in rainforests. We measured linearity and speed during off-trail travels toward out-of-sight locations as proxies for spatial knowledge. We found similarly high levels of linearity in individuals of Mbendjele foragers and Taï chimpanzees. However, human foragers and chimpanzees clearly differed in their reactions to group size and familiarity with the foraging areas. Mbendjele foragers increased travel linearity with increasing familiarity and group size, without obvious changes in speed. This pattern was reversed in Taï chimpanzees. We suggest that these differences between Mbendjele foragers and Taï chimpanzees reflect their different ranging styles, such as life-time range size and trail use. This result highlights the impact of socio-ecological settings on comparing spatial movement patterns. Our study provides a first step toward comparing long-range spatial movement patterns of two closely-related species in their natural environments.

The ability to know the direction of food sources is important for the foraging success of hunter–gatherers, especially in rainforests where dense vegetation limits visual detection distances. Besides sex and age, prior experience with the environment and the use of environmental cues are known to influence orientation abilities of humans. Among environmental cues, the position of the sun in the sky is important for orientation of diurnal animal species. However, whether or to what extent humans use the sun is largely unknown. Here, we investigated orientation abilities of the Mbendjele BaYaka people in the Republic of Congo, by conducting pointing tests (Nparticipants= 54, age: 6–76 years) in different locations in the rainforest. The Mbendjele were overall highly accurate at pointing to out-of-sight targets (median error: 6°). Pointing accuracy increased with age, but sex did not affect accuracy. Crucially, sun visibility increased pointing accuracy in young participants, especially when they were far from the camp. However, this effect became less apparent in older participants who exhibited high pointing accuracy, also when the sun was not visible. This study extends our understandings of orientation abilities of human foragers and provides the first behavioural evidence for sun compass use in humans.

This file includes Supplementary Texts with full details on ethics statement, study population, statistical analyses for the main model and sub-models for different types of target locations, as well as on data collection methods and statistical analyses for daily range patterns. Supplementary Figures (S1, S2) and Supplementary Tables (S1 to S8) are attached. The file also includes Supplementary Reference.

Copper oxide/reduced graphene oxide (rGO) hybrids have been successfully synthesized by attaching copper ions onto the functional groups of GO by means of a solution process, which causes precipitation and agglomeration of copper oxides during subsequent thermal reduction of the GO. The resulting copper oxide/rGO hybrid exhibited improved electrochemical performance compared to monolithic CuO, which is presumed to be due to rGO acting as a mechanical support that buffers the volume change in copper oxides that occurs as a result of the conversion reaction during charge/discharge cycling. Furthermore, it was found that the size of the copper oxide particles can be optimized by adjusting the annealing time, with a hybrid annealed for 30 min achieving a reversible capacity of 544 mA h g(-1) and an initial coulombic efficiency of 62.7%.

Introduction Progressive supranuclear palsy (PSP) is a parkinsonian syndrome that typically affects gait and oculomotor control. Early clinical features of PSP are cognitive impairment and nonspecific affective, behavioral disturbances, personality changes, memory defects, depression, apathy, or euphoria, whereas hypersexuality is rare in PSP. Dopamine agonists are the major risk factor triggering hypersexuality in patients with PSP. In this article, we report a patient presented with hypersexual behavior as an initial symptom before using dopamine agonists as a treatment. Case report A 62-year-old male patient without past psychiatric history, presented to the psychiatric clinic with complaints of slowly progressive cognitive impairment and hypersexuality. He thought his wife cheated on him and frequently attempted to have sex with his partner when awaked from sleep. He showed compulsive sexual behavior harassing a woman in the street with uncontrollable and irrepressible sexual urge. Initially, Mini Mental State Examination (MMSE) score was 24 out of 30 points. An MRI of the brain showed atrophy of the midbrain. One year after his inappropriate sexual behavior was worsen and he started to being treated with L-dopa. At age 64, he showed dysphagia, vertical gaze palsy, growling dysarthria. He was wheelchair-bound at the age of 65. The clinical features and neuroimaging data led to a diagnosis of PSP. Significance Compulsive sexual behavior in patients with PSP before using dopamine replacement therapy reported yet. Conclusion We suggest that inappropriate sexual behavior in PSP can be presented in early course of disease.