Socio-ecological correlates of neophobia in corvids

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Socio-ecological study ofPresbytis aygula in West Java

Field studies of the Sunda Island leaf monkey,Presbytis aygula, were made in the montane forests of West Java at an altitude of 1,400–1,800 m between September 1976 and August 1981. The troop size ofP. aygula varied from 3 to 12 animals and the population density was about 35 animals/km² in Patenggang and 11–12 animals/km² in Kamojang. They were organized essentially in one male troops, though the troops in the Patenggang area usually consisted of only an adult pair and its offspring. Home range size was about 14 ha in Patenggang and about 35–40 ha in Kamojang. Some of those ranges overlapped with each other. The differences between these two areas were considered to be the result of recent habitat destruction and human impact in Patenggang. Animals spent more time in resting than other activities during a day.P. aygula in Java, consumed mainly leaves, eating less fruits and other parts of plants. Troop cohesion was tight, but social interactions between troop members were rather infrequent. The patterns of intertroop encounters and vocal sounds were described.     

Socio-ecological biotechnology concepts for developing countries

Conclusions The two socio-ecological concepts described will work, of course, also with other microorganisms.Zymomonas mobilis can be replaced by yeast,Rhizopus could be replaced byAspergillus. However, both microorganisms which are presently used can produce by-products that are unsafe for human or animal consumption. It is therefore a microbiological challenge to find further microorganisms to expand the product formation.It should also be realized that the largest renewable resource, cellulose, has not been mentioned in the context of either concept. It is well known that cellulose must eventually be included if research and development can find ways and means to separate lignin from cellulose and convert cellulose to glucose in a similar and as easy a manner as starch (Doelle 1984).In order to be successful, fermentation processes have to be fast and efficient with a low energy input (Doelle 1986a, b; Doelle & Jones 1986). This excludes the traditional microbiological sterilization of substrates, excessive substrate or product inhibitions in any of these processes.A further omission of socio-ecological concepts lies in the fermented food production. It is encouraging to see the realization that fermented foods are mixedculture processes and that it is time to start detailed and extensive investigations into the functioning of such cultures (Doelle 1985; Steinkraus 1987; Okagbu 1988; Odunfa 1988). It is the suggestion of the author to encourage a review on mixed culture with particular emphasis on fermented food production and its waste disposal.     

From connection to contagion

This essay proposes that we ‘think data’ with a complex legacy of work, once disavowed and now resurgent in social theory, on crowd formations. I propose this move because social media platforms’ mobilization of data – the extractions, ever-shifting reaggregations, and micro-targeting, on the one hand, and our engagements, re-tweets, acts of sharing, and production of virality, on the other – has fuelled such anxious concern about the very things that animated much crowd theory in the first place. Key among these concerns are the force of emotional contagion and the threat of social dissolution; the composition of ‘the social’ by elements that well exceed the human; and pressing questions about the media through which energetic forces travel, often with lightning speed. What questions might be enabled by attending to the resonance between crowd theory's ‘anti-liberal’ preoccupations and contemporary concerns over how social media platforms crowd us?     

Socio-ecological analysis of desertification in the Mu-Us Sandy Land with satellite remote sensing

To understand the contemporary process of desertification in the Mu-Us Sandy Land, China, we assessed the current status of desertification from satellite images. We analyzed the effect of land use by comparing desertification images and GIS-based thematic data. Socioeconomic factors were studied through interviews with local people. The desertified area ratio in each village was related to the sand dune ratio. Desertification in this region was affected by the activity of sand dunes. The revegetated area ratio had a close relationship with the cropland ratio. The development of cropland and surrounding woods contributed to revegetation of desertified land. Desertified areas were distributed mainly in pastoral regions. Critical carrying capacity of grassland for sheep and goats was approximately 2 head/ha. High population density of goats was evident in the severely desertified ranges. Goats were increasingly introduced to earn money through modernization, but they overgrazed fenced pastures. Further environmental education is needed to promote sustainable land use.     

Yawn contagion and empathy in Homo sapiens

The ability to share others' emotions, or empathy, is crucial for complex social interactions. Clinical, psychological, and neurobiological clues suggest a link between yawn contagion and empathy in humans (Homo sapiens). However, no behavioral evidence has been provided so far. We tested the effect of different variables (e.g., country of origin, sex, yawn characteristics) on yawn contagion by running mixed models applied to observational data collected over 1 year on adult (>16 years old) human subjects. Only social bonding predicted the occurrence, frequency, and latency of yawn contagion. As with other measures of empathy, the rate of contagion was greatest in response to kin, then friends, then acquaintances, and lastly strangers. Related individuals (r≥0.25) showed the greatest contagion, in terms of both occurrence of yawning and frequency of yawns. Strangers and acquaintances showed a longer delay in the yawn response (latency) compared to friends and kin. This outcome suggests that the neuronal activation magnitude related to yawn contagion can differ as a function of subject familiarity. In conclusion, our results demonstrate that yawn contagion is primarily driven by the emotional closeness between individuals and not by other variables, such as gender and nationality.     

The cultural contagion of conflict

Anecdotal evidence abounds that conflicts between two individuals can spread across networks to involve a multitude of others. We advance a cultural transmission model of intergroup conflict where conflict contagion is seen as a consequence of universal human traits (ingroup preference, outgroup hostility; i.e. parochial altruism) which give their strongest expression in particular cultural contexts. Qualitative interviews conducted in the Middle East, USA and Canada suggest that parochial altruism processes vary across cultural groups and are most likely to occur in collectivistic cultural contexts that have high ingroup loyalty. Implications for future neuroscience and computational research needed to understand the emergence of intergroup conflict are discussed.     

Infectious disease modeling of social contagion in networks

Many behavioral phenomena have been found to spread interpersonally through social networks, in a manner similar to infectious diseases. An important difference between social contagion and traditional infectious diseases, however, is that behavioral phenomena can be acquired by non-social mechanisms as well as through social transmission. We introduce a novel theoretical framework for studying these phenomena (the SISa model) by adapting a classic disease model to include the possibility for 'automatic' (or 'spontaneous') non-social infection. We provide an example of the use of this framework by examining the spread of obesity in the Framingham Heart Study Network. The interaction assumptions of the model are validated using longitudinal network transmission data. We find that the current rate of becoming obese is 2 per year and increases by 0.5 percentage points for each obese social contact. The rate of recovering from obesity is 4 per year, and does not depend on the number of non-obese contacts. The model predicts a long-term obesity prevalence of approximately 42, and can be used to evaluate the effect of different interventions on steady-state obesity. Model predictions quantitatively reproduce the actual historical time course for the prevalence of obesity. We find that since the 1970s, the rate of recovery from obesity has remained relatively constant, while the rates of both spontaneous infection and transmission have steadily increased over time. This suggests that the obesity epidemic may be driven by increasing rates of becoming obese, both spontaneously and transmissively, rather than by decreasing rates of losing weight. A key feature of the SISa model is its ability to characterize the relative importance of social transmission by quantitatively comparing rates of spontaneous versus contagious infection. It provides a theoretical framework for studying the interpersonal spread of any state that may also arise spontaneously, such as emotions, behaviors, health states, ideas or diseases with reservoirs.     

Cooperation and contagion in web-based, networked public goods experiments

A longstanding idea in the literature on human cooperation is that cooperation should be reinforced when conditional cooperators are more likely to interact. In the context of social networks, this idea implies that cooperation should fare better in highly clustered networks such as cliques than in networks with low clustering such as random networks. To test this hypothesis, we conducted a series of web-based experiments, in which 24 individuals played a local public goods game arranged on one of five network topologies that varied between disconnected cliques and a random regular graph. In contrast with previous theoretical work, we found that network topology had no significant effect on average contributions. This result implies either that individuals are not conditional cooperators, or else that cooperation does not benefit from positive reinforcement between connected neighbors. We then tested both of these possibilities in two subsequent series of experiments in which artificial seed players were introduced, making either full or zero contributions. First, we found that although players did generally behave like conditional cooperators, they were as likely to decrease their contributions in response to low contributing neighbors as they were to increase their contributions in response to high contributing neighbors. Second, we found that positive effects of cooperation were contagious only to direct neighbors in the network. In total we report on 113 human subjects experiments, highlighting the speed, flexibility, and cost-effectiveness of web-based experiments over those conducted in physical labs.     

The contagion mechanism for the origin of sex

The origin of sex is one of the least understood aspects of the evolution of sex. Recently it has been proposed that sex arose as a result of a contagious genetic element which acted so as to foster its own transmission. Two continuous-time deterministic models of this mechanism are analysed. The first model lacks population regulation. With this assumption, sex is always established in the population, predominating if the sexual form is viable. The second model includes population regulation, giving rise to evolutionary dynamics in which sex need not be established in the population. In addition, with the second model, when the sexual form is viable, it need not fix. Thus, the contagion mechanism can give rise to sex, but need not do so.     

A generalized model of social and biological contagion

We present a model of contagion that unifies and generalizes existing models of the spread of social influences and microorganismal infections. Our model incorporates individual memory of exposure to a contagious entity (e.g. a rumor or disease), variable magnitudes of exposure (dose sizes), and heterogeneity in the susceptibility of individuals. Through analysis and simulation, we examine in detail the case where individuals may recover from an infection and then immediately become susceptible again (analogous to the so-called SIS model). We identify three basic classes of contagion models which we call epidemic threshold, vanishing critical mass, and critical mass classes, where each class of models corresponds to different strategies for prevention or facilitation. We find that the conditions for a particular contagion model to belong to one of the these three classes depend only on memory length and the probabilities of being infected by one and two exposures, respectively. These parameters are in principle measurable for real contagious influences or entities, thus yielding empirical implications for our model. We also study the case where individuals attain permanent immunity once recovered, finding that epidemics inevitably die out but may be surprisingly persistent when individuals possess memory.     

Nearshore contagion and sampling of freshwater larval fish

The existence of larval fish contagion and its approximate magnitudein four different biotopes: at the shore of a river, surfaceand at fixed depth at an exposed coast of a large lake, andin a shallow, sheltered bay, was investigated, using passiveand active sampling. Non-random distributions were the rule;patchiness differed according to species, size, abundance anddiurnal movement, and was inversely related to distance fromshore. Characterization of contagion was hindered by samplingequipment and techniques, which were found wanting.     

What Makes Socio-ecological Systems Robust? An Institutional Analysis of the 2,000 Year-Old Ifugao Society

Scholars have often puzzled over why ancient socio-ecological systems (SES) have collapsed or survived overtime. This paper examines the case of the 2,000-year old Ifugao SES in the northern Philippines and the contemporary challenges they now face. Five observations can be drawn. First, the Ifugao case does not fit some of the conventional theoretical explanations for the collapse or survival of SES. Second, the Ifugao’s primogeniture system of property rights along with the their customary laws and practices have played important roles in maintaining the robustness of their SES through their effects on ecological integrity. Third, the Ifugao SES today is faced with contemporary challenges with varying effects on its robustness: integration into a post-colonial social order, the effects of tourism and agricultural development, migration, urbanization and the introduction of Christianity and mass education. Fourth, despite these changes, it is not a certainty that the Ifugao will shift to a new domain of attraction that cannot support a human population, or that will induce a transition that causes long-term human suffering. Finally, the Ifugao case study adds to our understanding of robust SES.     

Conformational contagion in a protein: structural properties of a chameleon sequence

Certain sequences, known as chameleon sequences, take both alpha- and beta-conformations in natural proteins. We demonstrate that a wild chameleon sequence fused to the C-terminal alpha-helix or beta-sheet in foreign stable proteins from hyperthermophiles forms the same conformation as the host secondary structure. However, no secondary structural formation is observed when the sequence is attached to the outside of the secondary structure. These results indicate that this sequence inherently possesses an ability to make either alpha- or beta-conformation, depending on the sequentially neighboring secondary structure if little other nonlocal interaction occurs. Thus, chameleon sequences take on a satellite state through contagion by the power of a secondary structure. We propose this "conformational contagion" as a new nonlocal determinant factor in protein structure and misfolding related to protein conformational diseases.