Jumps in the Archimedean height

We introduce a pairing on local intersection cohomology groups of variations of pure Hodge structure, which we call the asymptotic height pairing. Our original application of this pairing was to answer a question on the Ceresa cycle posed by R. Hain and D. Reed. (This question has since been answered independently by Hain.) Here we show that a certain analytic line bundle, called the biextension line bundle, and defined in terms of normal functions, always extends to any smooth partial compactification of the base. We then show that the asymptotic height pairing on intersection cohomology governs the extension of the natural metric on this line bundle studied by Hain and Reed (as well as, more recently, by several other authors). We also prove a positivity property of the asymptotic height pairing, which generalizes the results of a recent preprint of J. Burgos Gil, D. Holmes and R. de Jong, along with a continuity property of the pairing in the normal function case. Moreover, we show that the asymptotic height pairing arises in a natural way from certain Mumford–Grothendieck biextensions associated to normal functions

New Zealand labour force participation: the ninety years to 1981

This paper emanines labour force participation in New Zealand from l891 to 1981. It commences with a brief review of previous work in the area and then draws upon data from the New Zealand Census of Population and Dwellings to investigate participation races. Age-specific data for Maoris, non-Maoris and Pacific Island Polynesians are analysed and male rates are compared with female rates. The paper concludes by identifying unresolved questions requiring further research

Method for processing clay ceramic materials

A method of forming bricks, tiles, and the like by treating clay, shale or other clay ceramic raw materials containing pyrite is disclosed. Such clay, ceramic raw materials may be ground, and then mixed with an oxidizer in a pre-oxidation step to disperse the oxidizer within the clay to expose the maximum amount of clay surface to the oxidizer. One oxidizer that may be used is an aqueous solution of hydrogen peroxide. Clay is shaped into clay products and then heated to elevated temperatures. Pyrite within the clay is oxidized, thereby removing sulfur-containing compounds such as sulfur dioxide from the clay. The application of the invention may assist in preventing efflorescense by ensuring complete or nearly complete removal of pyrite from products oxidation treatment and subsequent firing at elevated temperatures. Similarly, by enhancing the oxidation of pyrite, faster firing cycles may be possible which facilitates reduced fuel consumption and faster process time

Chimpanzee Autarky

Background: Economists believe that barter is the ultimate cause of social wealth—and even much of our human culture—yet little is known about the evolution and development of such behavior. It is useful to examine the circumstances under which other species will or will not barter to more fully understand the phenomenon. Chimpanzees (Pan troglodytes) are an interesting test case as they are an intelligent species, closely related to humans, and known to participate in reciprocal interactions and token economies with humans, yet they have not spontaneously developed costly barter. Methodology/Principle Findings: Although chimpanzees do engage in noncostly barter, in which otherwise value-less tokens are exchanged for food, this lack of risk is not typical of human barter. Thus, we systematically examined barter in chimpanzees to ascertain under what circumstances chimpanzees will engage in costly barter of commodities, that is, trading food items for other food items with a human experimenter. We found that chimpanzees do barter, relinquishing lower value items to obtain higher value items (and not the reverse). However, they do not trade in all beneficial situations, maintaining possession of less preferred items when the relative gains they stand to make are small. Conclusions/Significance: Two potential explanations for this puzzling behavior are that chimpanzees lack ownership norms, and thus have limited opportunity to benefit from the gains of trade, and that chimpanzees\u27 risk of defection is sufficiently high that large gains must be imminent to justify the risk. Understanding the conditions that support barter in chimpanzees may increase understanding of situations in which humans, too, do not maximize their gains

When Given the Opportunity, Chimpanzees Maximize Personal Gain Rather than “Level the Playing Field”

We provided chimpanzees (Pan troglodytes) with the ability to improve the quality of food rewards they received in a dyadic test of inequity.We were interested to see if this provision influenced their responses and, if so, whether it was mediated by a social partner’s outcomes. We tested eight dyads using an exchange paradigm in which, depending on the condition, the chimpanzees were rewarded with either high-value (a grape) or low-value (a piece of celery) food rewards for each completed exchange. We included four conditions. In the first, “Different” condition, the subject received different, less-preferred, rewards than their partner for each exchange made (a test of inequity). In the “Unavailable” condition, high-value rewards were shown, but not given, to both chimpanzees prior to each exchange and the chimpanzees were rewarded equally with low-value rewards (a test of individual contrast). The final two conditions created equity. In these High-value and Low-value “Same” conditions both chimpanzees received the same food rewards for each exchange.Within each condition, the chimpanzees first completed ten trials in the Baseline Phase, in which the experimenter determined the rewards they received, and then ten trials in the Test Phase. In the Test Phase, the chimpanzees could exchange tokens through the aperture of a small wooden picture frame hung on their cage mesh in order to receive the high-value reward. Thus, in the Test Phase, the chimpanzees were provided with an opportunity to improve the quality of the rewards they received, either absolutely or relative to what their partner received. The chimpanzees responded in a targeted manner; in the Test Phase they attempted to maximize their returns in all conditions in which they had received low-value rewards during the Baseline Phase. Thus, the chimpanzees were apparently motivated to increase their reward regardless of their partners’, but they only used the mechanism provided when it afforded the opportunity for them to increase their rewards.We also found evidence that the chimpanzees’ responses were enhanced by social facilitation. Specifically, the chimpanzees were more likely to exchange their tokens through the frame when their test partner also did so, even in circumstances in which their reward value could not be improved. Our paradigm provided the chimpanzees with the possibility to improve the quality of rewards they received in the Test Phase. We found that refusals – to exchange tokens or to eat rewards – decreased significantly in the Test Phase compared to the Baseline Phase, where no such opportunity for improvement of outcomes existed. Thus, the chimpanzees participated more when they could improve the rewards they received

Chimpanzees’ Socially Maintained Food Preferences Indicate both Conservatism and Conformity

Chimpanzees remain fixed on a single strategy, even if a novel, more efficient, strategy is introduced. Previous studies reporting such findings have incorporated paradigms in which chimpanzees learn one behavioural method and then are shown a new one that the chimpanzees invariably do not adopt. This study provides the first evidence that chimpanzees show such conservatism even when the new method employs the identical required behaviour as the first, but for a different reward. Groups of chimpanzees could choose to exchange one of two inedible tokens; one was rewarded with a highly preferred food (grape) and the other with a less preferred food (carrot). Individuals first observed a model chimpanzee from their social group trained to choose one of the two types of tokens. In one group, this token earned a carrot, while in the other, control, group the token earned a grape. In both groups, chimpanzees conformed to the trained model’s choice. This was especially striking for those gaining the pieces of carrot; the less favoured reward. This resulted in a population-level trend of food choices, even when counter to their original, individual, preferences. Moreover, the chimpanzees’ food preferences did not change over time, demonstrating that these results were not due to a simple shift in preferences. We discuss social factors apparent in the interactions and suggest that, despite seeming to be inefficient, in chimpanzees, conformity may benefit them, possibly by assisting with the maintenance of group relations

The Ontogeny of Social Comparisons by Rhesus Macaques (Macaca mulatta)

This longitudinal study investigated the development of social contrast-negative responses to inequitable rewards-in rhesus macaques (Macaca mulatta). Although responses to inequity by humans appear universal, this is something that develops with age. Infants first recognize inequity when around 18 months old and respond to it only when they are around 3 years old. To date, however, there have been no studies of the ontogeny of the inequity response in any species other than humans. To address this, we used an exchange paradigm, in which 10 pairs of rhesus monkeys had to exchange inedible tokens with the experimenter to get food rewards that differed in quality depending on the condition. All subjects were tested first when they were an average of 17 months old and a subset, of four pairs, was tested again a year later. Subjects responded negatively to contrast-recognizing a disparity in expected, as compared to, received rewards-based on both social and individual comparisons at the older age, but not at the younger age. Similar to humans, rhesus showed a developmental trajectory to social comparison, providing the first evidence for the ontogeny of this response in a non-human species