Open Access

It is well established that positive contact between members of different groups can reduce prejudice. However, there is also evidence that direct contact with advantaged group members can undermine disadvantaged group members' engagement in collective action. Also, considerable evidence shows that effective contact need not be direct. Mere knowledge of cross-group friendships (extended contact) or observing positive contact (vicarious contact) can also reduce prejudice. This raises the question of whether these indirect forms of contact might also undermine collective action. We conducted a mini-meta-analysis of eight unpublished studies, including a range of intergroup contexts and samples, that measured indirect contact with advantaged group members and collective action among disadvantaged groups. We found a small but significant relationship that was consistently negative but varied in size depending on how indirect contact was measured. Contrary to expectation, more indirect contact predicted reductions in normative forms of collective action as strongly as radical forms.

Polyurethane (PUR) soft foams release malodorous and potentially toxic compounds when exposed to oxidative conditions. Current chamber test methods cannot distinguish between pre-existing volatiles and those formed during oxidation, nor can they assess the formation rates of oxidation products. We subjected PUR soft foam to oxidative treatment in a continuous air flow at 120 ◦C. Emissions were convectively transferred from the foam to an exhaust port and analyzed using a thermodesorption–gas chromatography–mass spectrometry (TD-GC-MS) system, with external calibration employed for the quantification of selected analytes. The study identified hydroperoxide formation and degradation as key mechanisms in the breakdown of the polyether soft segments. This process predominantly produces volatiles, such as carboxylic acids, formates, acetates, alpha-hydroxy-ketones, (unsaturated) aldehydes, substituted dioxolanes and dioxanes, glycols, and allyl ethers. Volatiles associated with the degradation of the hard segments include aniline, benzoxazole, 2-methylbenzoxazole, and benzaldehyde. This experimental setup enables reproducible qualitative and quantitative analysis of volatiles formed during the oxidative degradation of PUR soft foams, providing new insights into the segment-dependent chemical pathways of the polymer’s molecular breakdown.