The Origin of Prosociality Toward Strangers

<p>Humans are champions of prosociality. Across different cultures and early in life, humans routinely engage in prosocial behaviors that benefit others. Perhaps most strikingly, humans are even prosocial toward strangers (i.e. xenophilic). This is an evolutionary puzzle because it cannot be explained by kinship theory, reciprocal altruism or reputation. The parochialism hypothesis proposes that this extreme prosociality is unique to humans, is motivated by unselfish motivation and evolved through group selection made possible by human culture and warfare. The first impression hypothesis, on the other hand, proposes that xenophilia can evolve to promote the selfish benefits that accrue from extending one's social network. It predicts that 1) nonhuman species can evolve prosociality toward strangers when the benefit of forming new relations is higher than the cost, 2) the motivation for prosociality can be selfish, and 3) encounters with strangers can be a positive social event since strangers represent potential social partners. This dissertation presents three sets of experiments designed to test these predictions with bonobos (Pan paniscus), a species known for reduced xenophobia. These experiments showed, first, that bonobos voluntarily shared monopolizable food with a stranger and helped the stranger to obtain out-of-reach food. Second, the observed prosociality was driven by a selfish motivation to initiate an interaction with the stranger in close proximity and an other-regarding motivation to benefit the stranger. Third, an involuntary yawning task and a voluntary choice task show converging results that bonobos attribute positive valence to completely unknown strangers by default. These experiments support the three core predictions of the first impression hypothesis and challenge the view that intergroup competition is crucial to the origin of prosociality toward strangers in our species. Instead, the first impression hypothesis proposes that xenophilia in bonobos is probably an adaptation to initiating non-kin cooperation. Because female bonobos are highly cooperative even though they are the dispersing sex, xenophilia might function to quickly establish cooperative relationships with new immigrants. This suggests that xenophilia and reciprocity are likely two complementary aspects of non-kin cooperation: the former explains its initiation while the latter explains its maintenance. Similarly, xenophilia in humans is likely a result of the increasing need for cooperation among non-kin due to enhanced fission-fusion dynamics, population expansion, obligate cooperative foraging and greater dependence on cultural knowledge.</p>Dissertatio

Bonobos voluntarily hand food to others but not toys or tools

This research was supported in part by National Science Foundation Graduate Research Fellowship DGE-1106401 and European Commission Marie-Sklodowska Curie European Fellowship MENTALIZINGORIGINS to C.K. and National Science Foundation grants NSF-BCS-08-27552-02 and NSF-BCS-10-25172 to B.H.A key feature of human prosociality is direct transfers, the most active form of sharing in which donors voluntarily hand over resources in their possession. Direct transfers buffer hunter-gatherers against foraging shortfalls. The emergence and elaboration of this behaviour thus likely played a key role in human evolution by promoting cooperative interdependence and ensuring that humans' growing energetic needs (e.g. for increasing brain size) were more reliably met. According to the strong prosociality hypothesis, among great apes only humans exhibit sufficiently strong prosocial motivations to directly transfer food. The versatile prosociality hypothesis suggests instead that while other apes may make transfers in constrained settings, only humans share flexibly across food and non-food contexts. In controlled experiments, chimpanzees typically transfer objects but not food, supporting both hypotheses. In this paper, we show in two experiments that bonobos directly transfer food but not non-food items. These findings show that, in some contexts, bonobos exhibit a human-like motivation for direct food transfer. However, humans share across a far wider range of contexts, lending support to the versatile prosociality hypothesis. Our species' unusual prosocial flexibility is likely built on a prosocial foundation we share through common descent with the other apes.PostprintPeer reviewe

A comparative framework of inter-individual coordination and pair-bonding

Inter-individual coordination (IIC) at the behavioral and physiological level, and its association with courtship and pair-bond maintenance, have been receiving increased attention in the scientific literature in recent years. However, there is no integrative framework combining the plethora of findings in humans and nonhuman species yet that addresses the evolutionary origins of IIC. Here, we take a comparative approach and review findings on the link between IIC and pair-bond formation, maintenance, and bi-parental care. Our review suggests that across socially monogamous species, IIC – at a behavioral and physiological level – is correlated with the likelihood of forming and retaining a pair-bond, and with reproductive success. We expand on the pair-bonding hypothesis by stating that higher levels of IIC might be beneficial for relationship quality and bi-parental care and, as a result, might also become a preferred trait in the formation and maintenance of a pair-bond. We further discuss the key questions to disentangle the evolution of IIC based on this hypothesis

Biological functions of endophytic bacteria in Robinia pseudoacacia ‘Hongsen’

IntroductionEndophytes and their host plants have co-evolved for a very long time. This relationship has led to the general recognition of endophytes as a particular class of microbial resources. R. pseudoacacia ‘Hongsen’ is drought- and barren-resistant species that can be grown in both the north and south of China, efficiently addresses the ecological issues caused by China’s ‘southern eucalyptus and northern poplar. Up to date, cultured-dependent studies are available for the R. pseudoacacia nitrogen-fixing and other endophytes. Therefore, the present research studied the R. pseudoacacia ‘Hongsen,’ microbiome in detail by high-throughput sequencing and culture dependant.MethodsThis study examined microbial species and functional diversity in Robinia pseudoacacia ‘Hongsen’ using culture-dependent (isolation) and culture-independent techniques.ResultsA total of 210 isolates were isolated from R. pseudoacacia ‘Hongsen.’ These isolates were clustered into 16 groups by the In Situ PCR (IS-PCR) fingerprinting patterns. 16S rRNA gene sequence analysis of the representative strain of each group revealed that these groups belonged to 16 species of 8 genera, demonstrating the diversity of endophytes in R. pseudoacacia ‘Hongsen’. ’Bacillus is the most prevalent genus among all the endophytic bacteria. High-throughput sequencing of endophytic bacteria from R. pseudoacacia ‘Hongsen’ of the plant and the rhizosphere soil bacteria showed that the bacterial populations of soil near the root, leaf, and rhizosphere differed significantly. The microbial abundance decreased in the endophytes as compared to the rhizosphere. We observed a similar community structure of roots and leaves. With and without root nodules, Mesorhizobium sp. was significantly different in R. pseudoacacia ‘Hongsen’ plant.DiscussionIt was predicted that R. pseudoacacia ‘Hongsen’ plant endophytic bacteria would play a significant role in the metabolic process, such as carbohydrate metabolism, amino acid metabolism, membrane transport, and energy metabolism

All-Trans-Retinoic Acid Suppresses Neointimal Hyperplasia and Inhibits Vascular Smooth Muscle Cell Proliferation and Migration via Activation of AMPK Signaling Pathway

The proliferation and migration of vascular smooth muscle cells (VSMC) is extensively involved in pathogenesis of neointimal hyperplasia. All-trans-retinoic acid (ATRA) is a natural metabolite of vitamin A. Here, we investigated the involvement of AMP-activated protein kinase (AMPK) in the anti-neointimal hyperplasia effects of ATRA. We found that treatment with ATRA significantly reduced neointimal hyperplasia in the left common carotid artery ligation mouse model. ATRA reduced the proliferation and migration of VSMC, A7r5 and HASMC cell lines. Our results also demonstrated that ATRA altered the expression of proliferation-related proteins, including CyclinD1, CyclinD3, CyclinA2, CDK2, CDK4, and CDK6 in VSMC. ATRA dose-dependently enhanced the phosphorylation level of AMPKα (Thr172) in the left common carotid artery of experimental mice. Also, the phosphorylation level of AMPKα in A7r5 and HASMC was significantly increased. In addition, ATRA dose-dependently reduced the phosphorylation levels of mTOR and mTOR target proteins p70 S6 kinase (p70S6K) and 4E-binding protein 1 (4EBP1) in A7r5 and HASMC. Notably, the inhibition of AMPKα by AMPK inhibitor (compound C) negated the protective effect of ATRA on VSMC proliferation in A7r5. Also, knockdown of AMPKα by siRNA partly abolished the anti-proliferative and anti-migratory effects of ATRA in HASMC. Molecular docking analysis showed that ATRA could dock to the agonist binding site of AMPK, and the binding energy between AMPK and ATRA was -7.91 kcal/mol. Molecular dynamics simulations showed that the binding of AMPK-ATRA was stable. These data demonstrated that ATRA might inhibit neointimal hyperplasia and suppress VSMC proliferation and migration by direct activation of AMPK and inhibition of mTOR signaling

A review on modelling methods, tools and service of integrated energy systems in China

An integrated energy system (IES) is responsible for aggregating various energy carriers, such as electricity, gas, heating, and cooling, with a focus on integrating these components to provide an efficient, low-carbon, and reliable energy supply. This paper aims to review the modeling methods, tools, and service modes of IES in China to evaluate opportunities for improving current practices. The models reviewed in this paper are classified as demand forecasting or energy system optimization models based on their modeling progress. Additionally, the main components involved in the IES modeling process are presented, and typical domestic tools utilized in the modeling processes are discussed. Finally, based on a review of several demonstration projects of IES, future development directions of IES are summarized as the integration of data-driven and engineering models, improvements in policies and mechanisms, the establishment of regional energy management centers, and the promotion of new energy equipment

Hysteresis of Electronic Transport in Graphene Transistors

Graphene field effect transistors commonly comprise graphene flakes lying on SiO2 surfaces. The gate-voltage dependent conductance shows hysteresis depending on the gate sweeping rate/range. It is shown here that the transistors exhibit two different kinds of hysteresis in their electrical characteristics. Charge transfer causes a positive shift in the gate voltage of the minimum conductance, while capacitive gating can cause the negative shift of conductance with respect to gate voltage. The positive hysteretic phenomena decay with an increase of the number of layers in graphene flakes. Self-heating in helium atmosphere significantly removes adsorbates and reduces positive hysteresis. We also observed negative hysteresis in graphene devices at low temperature. It is also found that an ice layer on/under graphene has much stronger dipole moment than a water layer does. Mobile ions in the electrolyte gate and a polarity switch in the ferroelectric gate could also cause negative hysteresis in graphene transistors. These findings improved our understanding of the electrical response of graphene to its surroundings. The unique sensitivity to environment and related phenomena in graphene deserve further studies on nonvolatile memory, electrostatic detection and chemically driven applications.Comment: 13 pages, 6 Figure