Taxonomy based on science is necessary for global conservation

Peer reviewe

Processing power limits social group size: computational evidence for the cognitive costs of sociality

Sociality is primarily a coordination problem. However, the social (or communication) complexity hypothesis suggests that the kinds of information that can be acquired and processed may limit the size and/or complexity of social groups that a species can maintain. We use an agent-based model to test the hypothesis that the complexity of information processed influences the computational demands involved. We show that successive increases in the kinds of information processed allow organisms to break through the glass ceilings that otherwise limit the size of social groups: larger groups can only be achieved at the cost of more sophisticated kinds of information processing that are disadvantageous when optimal group size is small. These results simultaneously support both the social brain and the social complexity hypotheses

Bipedality and hair loss in human evolution revisited: The impact of altitude and activity scheduling.

Bipedality evolved early in hominin evolution, and at some point was associated with hair loss over most of the body. One classic explanation (Wheeler 1984: J. Hum. Evol. 13, 91-98) was that these traits evolved to reduce heat overload when australopiths were foraging in more open tropical habitats where they were exposed to the direct effects of sunlight at midday. A recent critique of this model (Ruxton and Wilkinson 2011a: Proc. Natl. Acad. Sci. USA 108, 20965-20969) argued that it ignored the endogenous costs of heat generated by locomotion, and concluded that only hair loss provided a significant reduction in heat load. We add two crucial corrections to this model (the altitude at which australopiths actually lived and activity scheduling) and show that when these are included there are substantial reductions in heat load for bipedal locomotion even for furred animals. In addition, we add one further consideration to the model: we extend the analysis across the full 24 h day, and show that fur loss could not have evolved until much later because of the thermoregulatory costs this would have incurred at the altitudes where australopiths actually lived. Fur loss is most likely associated with the exploitation of open habitats at much lower altitudes at a much later date by the genus Homo

Processing power limits social group size: computational evidence for the cognitive costs of sociality

Sociality is primarily a coordination problem. However, the social (or communication) complexity hypothesis suggests that the kinds of information that can be acquired and processed may limit the size and/or complexity of social groups that a species can maintain. We use an agent-based model to test the hypothesis that the complexity of information processed influences the computational demands involved. We show that successive increases in the kinds of information processed allow organisms to break through the glass ceilings that otherwise limit the size of social groups: larger groups can only be achieved at the cost of more sophisticated kinds of information processing that are disadvantageous when optimal group size is small. These results simultaneously support both the social brain and the social complexity hypotheses

Cooperation, behavioural synchrony and status in social networks

In this paper we present a new approach to modelling group coordination, based on dyadic synchronisation in a non-panmictic, structured network (a problem that applies widely to all species that live in medium to large groups). Using this approach, we present three models with three new theoretical results. (1) Multi-layered networks are optimal for groups that face costs associated with maintaining relationships among the members, combined with costs associated with information flow. (2) The presence of a social hierarchy can be an adaptive feature of the community: the steeper the optimal social hierarchy is, the fewer relationships group members need to have. (3) Falling communication costs lead to a less steep optimal social hierarchy in communities in which socially useful information is evenly distributed, but to an even steeper social hierarchy in groups in which socially useful information is uneven. Thus we show how, when communication is costly, cooperation can give rise to communities that are socially highly structured

Processing power limits social group size: computational evidence for the cognitive costs of sociality.

Sociality is primarily a coordination problem. However, the social (or communication) complexity hypothesis suggests that the kinds of information that can be acquired and processed may limit the size and/or complexity of social groups that a species can maintain. We use an agent-based model to test the hypothesis that the complexity of information processed influences the computational demands involved. We show that successive increases in the kinds of information processed allow organisms to break through the glass ceilings that otherwise limit the size of social groups: larger groups can only be achieved at the cost of more sophisticated kinds of information processing that are disadvantageous when optimal group size is small. These results simultaneously support both the social brain and the social complexity hypotheses

Life course similarities on social networking sites

Dyadic social relations are known to exhibit homophily − attraction and bonding between similar individuals − and recent studies have detected homophily also on the social network level. Here, we investigate whether social media networks exhibit signs of homophily with regards to life stages. Using a large and global database (N = 111,863) of social media profile pictures, we investigate proportions of picture types in an individual’s social network. Typical stages of young adulthood include peer group formation, mate searching, union formation, and parenting. We studied to what extent different association categories with pictures of one or several individuals correlated with each other. Results showed that users with a profile picture of a single individual were more likely to have other profile pictures of single individuals of the opposite sex, but not of the same sex, in their social media network. Profile pictures of heterosexual couples were more likely to appear with other heterosexual couple pictures, and profiles with baby pictures were strongly associated with the frequency of other baby pictures within the same network; both of these types were negatively associated with the frequency of pictures of singles. Pictures of two females together were positively linked with the largest number of other association types. The results probably reflect both selection and contagion effects. We conclude that contemporary social media networks appear to exhibit homophily in displays related to mate searching, pair bonds, and the transition to parenthood

Prevalencia y factores asociados a calculo dental y enfermedades periodontal en los perros del distrito de Huánuco

TesisSe estudiaron 120 caninos para determinar la prevalencia de cálculo y enfermedad periodontal (Gingivitis y Periodontitis) en la ciudad de Huánuco. A los 120 canes se les realizo un examen clínico estomatognático con la finalidad de diagnosticar la presencia de cálculos dentales, gingivitis y periodontitis y determinar la relación según la edad a la que se agrupo de 1-3 años, 4-7 años y de 8-10 años, tipo de alimentación (balanceado, casero y mixto) y estructura anatómica del cráneo (dolicocefalicos, mesocefalicos y braquiocefálico), mediante observación directa y la anamnesis Encontrando la prevalencia de cálculo dental de 60.80%, gingivitis 24.13% y de periodontitis 60.70% Al realizar un análisis comparativo entre la gingivitis y las variables edad existe relación estadística pero no se encontró relación entre gingivitis con la estructura anatómica y el tipo de alimento lo que significa que la dieta y el tipo de cráneo no influye sobre la enfermedad gingival, pero sí la periodontitis tiene relación con la edad, tipo de alimentación y tipo de cráneo