Female squirrel monkeys' (Saimiri boliviensis) responses to inequity in a group context; testing a link between cooperation and inequity responses.

Primates of several species respond negatively to receiving less preferred rewards than a partner for completing the same task (inequity responses), either rejecting rewards or refusing to participate in the task when disadvantaged. This has been linked to cooperation, with species that cooperate frequently refusing to participate in inequity tasks (the 'cooperation hypothesis'). However, inequity is a social response, and previous research has involved dyads, precluding studying the effects of additional social partners. While dyads allow for tighter control in experimental settings, dyadic interactions in nature do not take place in a social vacuum, so understanding the role of the social context is needed to verify that the pattern of results supports the cooperation hypothesis. Here we focus on Bolivian squirrel monkeys, Saimiri boliviensis, a highly social species that does not generally cooperate and has not responded to inequity in previous dyadic research, although they do respond to receiving a lower reward than they expected. In the current study, we provide a more nuanced test by studying female Bolivian squirrel monkeys, the demographic most likely to cooperate in both field and laboratory contexts, in a more socially relevant group setting. For some reward values, females responded in both the inequity condition, rejecting less preferred rewards when they were disadvantaged relative to their social group, and a contrast condition, wherein all animals received a lower reward than they expected, making it difficult to disentangle contrast from inequity. As in capuchin monkeys, refusals increased when monkeys were to receive low-value rewards compared to medium-value rewards. These results suggest that the relationship between cooperation and inequity responses may be more nuanced than previously suggested, with demographic, social context and reward value potentially influencing outcomes even within species.

The importance of thinking about the future in culture and cumulative cultural evolution.

Thinking about possibilities plays a critical role in the choices humans make throughout their lives. Despite this, the influence of individuals' ability to consider what is possible on culture has been largely overlooked. We propose that the ability to reason about future possibilities or prospective cognition, has consequences for cultural change, possibly facilitating the process of cumulative cultural evolution. In particular, by considering potential future costs and benefits of specific behaviours, prospective cognition may lead to a more flexible use of cultural behaviours. In species with limited planning abilities, this may lead to the development of cultures that promote behaviours with future benefits, circumventing this limitation. Here, we examine these ideas from a comparative perspective, considering the relationship between human and nonhuman assessments of future possibilities and their cultural capacity to invent new solutions and improve them over time. Given the methodological difficulties of assessing prospective cognition across species, we focus on planning, for which we have the most data in other species. Elucidating the role of prospective cognition in culture will help us understand the variability in when and how we see culture expressed, informing ongoing debates, such as that surrounding which social learning mechanisms underlie culture. This article is part of the theme issue 'Thinking about possibilities: mechanisms, ontogeny, functions and phylogeny'.

Personality and facial morphology: Links to assertiveness and neuroticism in capuchins (Sapajus [Cebus] apella).

Personality has important links to health, social status, and life history outcomes (e.g. longevity and reproductive success). Human facial morphology appears to signal aspects of one's personality to others, raising questions about the evolutionary origins of such associations (e.g. signals of mate quality). Studies in non-human primates may help to achieve this goal: for instance, facial width-to-height ratio (fWHR) in the male face has been associated with dominance not only in humans but also in capuchin monkeys. Here we test the association of personality (assertiveness, openness, attentiveness, neuroticism, and sociability) with fWHR, face width/lower-face height, and lower face/face height ratio in 64 capuchins (Sapajus apella). In a structural model of personality and facial metrics, fWHR was associated with assertiveness, while lower face/face height ratio was associated with neuroticism (erratic vs. stable behaviour) and attentiveness (helpfulness vs. distractibility). Facial morphology thus appears to associate with three personality domains, which may act as a signal of status in capuchins.

The reported use of dietary supplements (sip feeds) in hospitals in Wessex, UK.

AIMS: To assess the prevalence of the use of supplements (sip feeds) in district general, psychiatric and community hospitals in the former Wessex health region. METHOD: Cross sectional study of prevalence and determinants of supplement use in 10 district general hospitals (covering medical, surgical, orthopaedic, and elderly specialities), 4 psychiatric hospitals and 3 community hospitals. RESULTS: Overall 14% of patients were being supplemented although the variation across hospitals and specialities was wide (0%-35%); elderly care patients within district hospitals were most likely to be supplemented (20%; range 12-35%). In 34% of patients there was no documented reason as to why supplements were given. 60% of patients were not weighed on admission; 70% did not have a weight history recorded and 83% did not have a current weight recorded. Documentation regarding supplement use appeared to be recorded in an unsystematic manner. CONCLUSIONS: Many patients were not being weighed on admission and appeared to have no documentation as to why supplements were given. Given the importance of malnutrition in hospital patients a more evidence based, objective approach to assessing nutritional requirements, intake and support may be beneficial.

A semiquantitative analysis of the dynamics of a Goldman-type vaporiser.

When a turbulent flow of a carrier gas is passed over a liquid anaesthetic agent contained in a vaporiser of Goldman design, evaporation from the cooled surface leads rapidly to a succession of fluid instabilities which set in at characteristic critical conditions. An initially quiescent boundary layer at the surface is sequentially replaced by a thin layer of toroidal (Bénard-Marangoni) convection cells which are driven by surface tension gradients. These are then augmented by Rayleigh-Bénard convection driven by gravity, the whole process terminating in intermittent columnar plunging of cold fluid from a chaotic surface layer of pulsating thickness to the base of the liquid pool. Residual striations from these plunging columns persist throughout the bulk of the liquid so long as evaporation continues. The ultimate state is then one in which turbulence occurs throughout both liquid and vapour phases. In this paper, a semiquantitative analysis of the system dynamics is given with supportive experimental evidence where possible.

Controlled ventilation using isoflurane with an in-circle vaporiser.

We studied 19 patients anaesthetised for routine surgery using isoflurane delivered from a Komesaroff vaporiser mounted within a circle system. Their lungs were ventilated using a Penlon Nuffield ventilator attached to the circle system by a trunk of tubing. Fresh gas flow rates of 1, 2 or 31.min-1 were used. The inspired agent concentration was measured using a Datex Ultima multigas analyser and was found to be stable and easily controlled.

Isoflurane concentrations using uncompensated vaporisers within circle systems.

In a series of studies designed to investigate the need for a temperature-compensated vaporiser for use in a circle system, we first studied temperature changes within and isoflurane concentration delivered by a Komesaroff vaporiser during bench tests using different gas flows. Agent temperature and vapour concentration decreased as predicted by the Antoine equation. Using the vaporiser within a circle system during clinical anaesthesia, we then studied 20 patients breathing spontaneously and a further 10 patients receiving controlled ventilation, measuring the temperature of the agent within the vaporiser and the concentration of agent inspired by a the patient. In clincial use with the frest gas flows of 1-3.min-1, the inspired agent concentration did not decrease despite the decrease in temperature of the liquid isoflurane in the vaporiser.

High-efficiency joule-level Raman generation in Pb vapor.

We have obtained nearly 1 J of blue-green radiation in 60-nsec pulses by Raman shifting an injection-locked XeCl laser in Pb vapor. The measured 50% Raman energy conversion has been observed in both oscillator and oscillator-amplifier experiments. These results indicate that an XeCl/Pb blue-green laser efficiency of >1.4% should be possible.