Punctuated equilibrium and linear progression: Toward a new understanding of group development

This study proposes gaining a new understanding of group development by considering the integrative and the punctuated equilibrium models of group development as complementary rather than competing. We hypothesized that we would observe both punctuated equilibrium and linear progression in content-analyzed data from 25 simulated project teams, albeit on different dimensions. We predicted changes in time awareness and in task and pacing activity in line with the punctuated equilibrium model and changes in structure and process on task and socioemotional dimensions in line with the integrative model. Results partially supported predictions for both models.

A new crocodilian from the Lower Cretaceous Crato Formation of north-eastern Brazil

A new mesosuchian crocoddian from the Nova Olinda Member of the Crato Formation (Lower Cretaceous, Aptian) of north-eastern Brazil is described. Susisuchus anatoceps gen. et sp. nov. is the first crocodillan to be reported from this formation. It is represented by an incomplete, partially articulated skeleton: the skull and mandible, partial postcranial axial skeleton, forelimbs and portions of the osteodermal skeleton. Preservation of soft tissues includes the skin surrounding both forelimbs and the digits of the right hand. The state of preservation of the specimen suggests that it was incorporated into the basin as a desiccated carcass. Susisuchus anatoceps is one of the oldest crocodilians with a eusuchian-type dorsal shield, comprising a tetraserial paravertebral shield and, either side of this, two sagittal rows of accessory osteoderms. It also possesses amphicoelous thoracic, lumbar and caudal vertebrae. This combination of postcranial features have never before been seen in a crocodilian and warrant the erection of a new family within Mesosuchia: Susisuchidae. Taxonomically, S. anatoceps is similar to a number of Lower Cretaceous mesosuchians previously considered to have given rise to eusuchians, most notably the Glen Rose crocodilian and a new, but as yet undescribed crocodillan from the Lower Cretaceous Winton Formation of western Queensland, Australia. Preliminary preparation of the Winton crocodilian indicates that it may belong to Susisuchidae, supporting the hypotheses of interchange between the vertebrate faunas of South America and Australia during the Lower Cretaceous.

International images and mass media: The effects of media coverage on Canadians' perceptions of ethnic and race relations in Australia

Recently, there has been much speculation about the impact of international media coverage of Australia's position on Indigenous people, migrants and asylum seekers on other nations' images of Australia. In this experiment we examined whether there was any basis for such concerns by considering the short-term impact of negative TV coverage of Australians on Canadian viewers. A questionnaire provided baseline data on Canadian students' perceptions of Australians and Australian race relations. Four months later, the students were assigned to one of three conditions that varied media contact with Australians. Students viewed one of two television programs (about right-wing political independent, Pauline Hanson, and her emotive criticisms of Aborigines and Asian immigrants or about an ethnically-mixed group of young Australians and their positive sense of cultural identity), or they viewed no program (no contact control). Results indicated that both positive and negative media coverage of Australians affected Canadians' views of Australia in the short-term. In particular, negative coverage (of Hanson) promoted less favourable views of Australians and Australian race relations over time and relative to the positive media and no media control conditions. The media's role in shaping international images is discussed.

Leaders and their treatment of subgroups: implications for evaluations of the leader and the superordinate group

This experiment examined members' evaluations of a group leader and the group in contexts where a superordinate group comprised two subgroups and the group leader was aligned with one or other subgroup. The design varied group leader (ingroup, outgroup) and leader behavior (ingroup favoring, outgroup favoring) as well as the broader comparative context (intragroup, intergroup). Across a number of measures, results indicated a consistent Group Leader x Leader Behavior interaction that was independent of comparative context. Although group members were most satisfied with an ingroup leader who favored the ingroup, ingroup leaders were perceived positively irrespective of their behavior Outgroup leaders who unexpectedly favored the other subgroup were also perceived positively. However, outgroup leaders who favored their own subgroup were perceived as less fair and as more biased than other leaders. They also engendered less identification with the superordinate group and a less unified perception of the group. Results demonstrate the importance of social identity concerns to leadership in nested group contexts and emphasize the fact that perceptions of leader fairness and concern for the common group mediate responses to the superordinate category. Copyright (C) 2003 John Wiley Sons, Ltd.

Biogenic amines in Australian animal by-product meals

Biogenic amines were determined in Australian by-product meals including fish meals, poultry meals, meat meals, feather meals and blood meals. They were extracted with 0.1 mol/L HCl, derivatised with dansyl chloride and analysed using HPLC with UV detection at 254 nm. Median levels of putrescine, cadaverine and histamine were determined in the by-product meals, with the ranges being 13-102 mg/kg, 7-220 mg/kg and 4-570 mg/kg, respectively. High levels of biogenic amines were found particularly in fish meals. The results indicate that further studies are required to determine the maximum limits for biogenic amines in by-product meals that will not impair production when fed to poultry.