Escalated police stops of Black men are linguistically and psychologically distinct in their earliest moments.

Across the United States, police chiefs, city officials, and community leaders alike have highlighted the need to de-escalate police encounters with the public. This concern about escalation extends from encounters involving use of force to routine car stops, where Black drivers are disproportionately pulled over. Yet, despite the calls for action, we know little about the trajectory of police stops or how escalation unfolds. In study 1, we use methods from computational linguistics to analyze police body-worn camera footage from 577 stops of Black drivers. We find that stops with escalated outcomes (those ending in arrest, handcuffing, or a search) diverge from stops without these outcomes in their earliest moments-even in the first 45 words spoken by the officer. In stops that result in escalation, officers are more likely to issue commands as their opening words to the driver and less likely to tell drivers the reason why they are being stopped. In study 2, we expose Black males to audio clips of the same stops and find differences in how escalated stops are perceived: Participants report more negative emotion, appraise officers more negatively, worry about force being used, and predict worse outcomes after hearing only the officer's initial words in escalated versus non-escalated stops. Our findings show that car stops that end in escalated outcomes sometimes begin in an escalated fashion, with adverse effects for Black male drivers and, in turn, police-community relations.

The Prochlorococcus carbon dioxide-concentrating mechanism: evidence of carboxysome-associated heterogeneity.

The ability of Prochlorococcus to numerically dominate open ocean regions and contribute significantly to global carbon cycles is dependent in large part on its effectiveness in transforming light energy into compounds used in cell growth, maintenance, and division. Integral to these processes is the carbon dioxide-concentrating mechanism (CCM), which enhances photosynthetic CO2 fixation. The CCM involves both active uptake systems that permit intracellular accumulation of inorganic carbon as the pool of bicarbonate and the system of HCO3 (-) conversion into CO2. The latter is located in the carboxysome, a microcompartment designed to promote the carboxylase activity of Rubisco. This study presents a comparative analysis of several facets of the Prochlorococcus CCM. Our analyses indicate that a core set of CCM components is shared, and their genomic organization is relatively well conserved. Moreover, certain elements, including carboxysome shell polypeptides CsoS1 and CsoS4A, exhibit striking conservation. Unexpectedly, our analyses reveal that the carbonic anhydrase (CsoSCA) and CsoS2 shell polypeptide have diversified within the lineage. Differences in csoSCA and csoS2 are consistent with a model of unequal rates of evolution rather than relaxed selection. The csoS2 and csoSCA genes form a cluster in Prochlorococcus genomes, and we identified two conserved motifs directly upstream of this cluster that differ from the motif in marine Synechococcus and could be involved in regulation of gene expression. Although several elements of the CCM remain well conserved in the Prochlorococcus lineage, the evolution of differences in specific carboxysome features could in part reflect optimization of carboxysome-associated processes in dissimilar cellular environments.