Diffusion-driven proton exchange membrane fuel cell for converting fermenting biomass to electricity.

A membrane-integrated proton exchange membrane fuel cell that enables in situ fermentation of sugar to ethanol, diffusion-driven separation of ethanol, and its catalytic oxidation in a single continuous process is reported. The fuel cell consists of a fermentation chamber coupled to a direct ethanol fuel cell. The anode and fermentation chambers are separated by a reverse osmosis (RO) membrane. Ethanol generated from fermented biomass in the fermentation chamber diffuses through the RO membrane into a glucose solution contained in the DEFC anode chamber. The glucose solution is osmotically neutral to the biomass solution in the fermentation chamber preventing the anode chamber from drying out. The fuel cell sustains >1.3 mW cm(-2) at 47°C with high discharge capacity. No separate purification or dilution is necessary, resulting in an efficient and portable system for direct conversion of fermenting biomass to electricity.

Intergroup relations: insights from a theoretically integrative approach.

In social psychology, specific research traditions, which often spring up in response to external events or social problems, tend to perpetuate the theoretical assumptions and methodological approaches with which they began. As a result, theories and methods that have proven powerful in 1 topic area are often not applied in other areas, even to conceptually similar issues. The authors adopt a theoretically integrative approach to the topic of intergroup relations. Theories and empirical approaches from the domains of attitudes, impression formation, the self, personal relationships, and norms offer many new insights into problematic issues, such as repeated findings of dissociations among stereotyping, prejudice, and discrimination. This integrative approach not only promises new theoretical advances, but also suggests numerous potential practical approaches to limiting or reducing destructive patterns of intergroup relations.

On-line and memory-based modification of attitudes: determinants of message recall-attitude change correspondence.

Experiments investigated the impact of message elaboration on attitude change-message recall correspondence when attitude change occurs in an on-line (as attitude-relevant information is received), or memory-based (on the basis of retrieved attitude-relevant information) fashion. In 2 experiments, Ss' processing goals were manipulated to increase or inhibit on-line change and message elaboration. As predicted, Ss reported postexposure attitudes more rapidly in on-line vs memory-based conditions. Decreased message elaboration increased attitude-recall correspondence, regardless of when attitude change occurred. Increased elaboration produced elaboration-attitude judgment correspondence. Results suggest that recall of message content will best predict persuasion when message content is encoded free of elaborations, regardless of when attitude change occurs.

Processing deficits and the mediation of positive affect in persuasion.

Motivational and cognitive mediators of the reduced processing of persuasive messages shown by recipients in a positive mood were tested. Ss in positive or neutral moods read strong or weak counterattitudinal advocadies for either a limited time or for as long as they wanted. Under limited exposure conditions, neutral mood Ss showed attitude change indicative of systemic processing, whereas positive mood Ss showed no differentiation of strong and weak versions of the message. When message exposure was unlimited, positive mood Ss viewed the message longer than did neutral mood Ss and systematically processed it rather than relying on persuasion heuristics. These findings replicated with 2 manipulations of mood and 2 different attitude issues. We interpret the results as providing evidence that reduced cognitive capacity to process the message contributes to the decrements shown by positive mood Ss.

The impact of stereotype-incongruent information on perceived group variability and stereotype change.

Three experiments showed increases in the perceived variability of social groups after perceivers received stereotype-incongruent information about group members. In Experiment 1, participants generated flatter distributions after exposure to incongruent information, compared with equally deviant congruent information, in the form of typical verbal materials. Experiment 2 indicated similar changes in dispersion after the presentation of numeric information about a single group member. In Experiment 3, the authors manipulated cognitive load at encoding or at the time group judgments were requested. Under conditions of cognitive constraint, stereotype-incongruent information ceased to promote more dispersed group representations. These results are consistent with the idea that incongruent information triggers more deliberative and comprehensive retrieval and generation of exemplars. The authors discuss the implications of these findings for stereotype change.

Mood effects on attitude judgments: independent effects of mood before and after message elaboration.

This study investigated the independent effects of induced mood on the encoding of persuasive messages and on the assessment of attitude judgments. In Experiment 1, positive or negative mood was induced either before the encoding of a counterattitudinal message or before the assessment of attitude judgments. When mood was induced before message presentation, Ss in a bad mood were more persuaded by strong than by weak arguments, whereas Ss in a good mood were equally persuaded by strong and by weak arguments. When Ss encoded the message in a neutral mood, however, the advantage of strong over weak arguments was more pronounced when Ss were in a good rather than in a bad mood at the time of attitude assessment. In Experiment 2, Ss exposed to a counterattitudinal message composed of either strong or weak arguments formed either a global evaluation or a detailed representation of the message. Positive, negative, or neutral mood was then induced. Ss in a good mood were most likely and Ss in a negative mood least likely to base their reported attitudes on global evaluations.

Intergroup emotions: explaining offensive action tendencies in an intergroup context.

Three studies tested the idea that when social identity is salient, group-based appraisals elicit specific emotions and action tendencies toward out-groups. Participants' group memberships were made salient and the collective support apparently enjoyed by the in-group was measured or manipulated. The authors then measured anger and fear (Studies 1 and 2) and anger and contempt (Study 3), as well as the desire to move against or away from the out-group. Intergroup anger was distinct from intergroup fear, and the inclination to act against the out-group was distinct from the tendency to move away from it. Participants who perceived the in-group as strong were more likely to experience anger toward the out-group and to desire to take action against it. The effects of perceived in-group strength on offensive action tendencies were mediated by anger.

Affect and stereotyping: the effect of induced mood on distinctiveness-based illusory correlations.

In 2 studies, the effects of mood on the formation of distinctiveness-based illusory correlations were examined. After exposure to stimuli inducing positive, neutral, or negative mood, Ss read information about behaviors performed by members of 2 groups in an illusory correlation paradigm. In both experiments, only Ss in a neutral mood formed illusory correlations. In addition, Experiment 2 assessed Ss' processing latencies as a means of investigating differential attention to distinctive behaviors. Only Ss in a neutral mood differentially attended to the minority group's infrequent behaviors. Induced mood apparently interfered with the processing necessary to differentially encode distinctive stimuli, undermining the illusory correlation effect.

Processing of persuasive in-group messages.

Two studies investigated the processes mediating the persuasive impact of messages representing in-group opinions. In the 1st study, subjects read either a strong or a weak message attributed to either an in-group member or to another group. Subjects were more persuaded by a strong message from the in-group than a weak one, suggesting content-focused processing of the in-group message. Subjects were equally unpersuaded by either a strong or a weak message from the other group, and showed little sign of message processing. In the 2nd study, Ss listened to in-group or other-group messages about issues that varied in their relevance to in-group membership. When the issue was relevant to the in-group, subjects were persuaded by a strong message from the in-group, unpersuaded by a weak message from the in-group, and equally unimpressed by strong and weak messages from the other group. When the issue was irrelevant to the in-group, subjects accepted the position advocated by the in-group regardless of message quality, and again ignored messages from the other group. These results suggest that increased message processing, and not merely the impact of source persuasion cues, can underlie in-group-mediated attitude change.