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Social exclusion is complex, intractable, and devastating. It occurs where individuals or groups cannot fully participate in the typical activities of the societies in which they live, whether they are excluded economically, politically, or live in segregation. In this review, I highlight recent work in the area of social exclusion and ethnicity, focusing on Europe and Eurasia. Scholarship reveals ethnic hierarchies of exclusion in hiring and housing markets, educational approaches that cloak assimilationist practice in the language of inclusion, a plethora of strategies that minorities use to navigate exclusion, and more. While new research brings innovation and insight, it nevertheless remains fragmented along several dimensions. As scholars work to move the field forward, bridging substantive areas of exclusion, studying the complex dynamic of interactions between majorities and minorities, and collaborating across methodological divides would be particularly valuable.

Clinical practice, data collection, and medical AI constitute self-reinforcing and interacting cycles of exclusion

The biochemical and physical factors controlling protein expression level and solubility in vivo remain incompletely characterized. To gain insight into the primary sequence features influencing these outcomes, we performed statistical analyses of results from the high-throughput protein-production pipeline of the Northeast Structural Genomics Consortium. Proteins expressed in E. coli and consistently purified were scored independently for expression and solubility levels. These parameters nonetheless show a very strong positive correlation. We used logistic regressions to determine whether they are systematically influenced by fractional amino acid composition or several bulk sequence parameters including hydrophobicity, sidechain entropy, electrostatic charge, and predicted backbone disorder. Decreasing hydrophobicity correlates with higher expression and solubility levels, but this correlation apparently derives solely from the beneficial effect of three charged amino acids, at least for bacterial proteins. In fact, the three most hydrophobic residues showed very different correlations with solubility level. Leu showed the strongest negative correlation among amino acids, while Ile showed a slightly positive correlation in most data segments. Several other amino acids also had unexpected effects. Notably, Arg correlated with decreased expression and, most surprisingly, solubility of bacterial proteins, an effect only partially attributable to rare codons. However, rare codons did significantly reduce expression despite use of a codon-enhanced strain. Additional analyses suggest that positively but not negatively charged amino acids may reduce translation efficiency in E. coli irrespective of codon usage. While some observed effects may reflect indirect evolutionary correlations, others may reflect basic physicochemical phenomena. We used these results to construct and validate predictors of expression and solubility levels and overall protein usability, and we propose new strategies to be explored for engineering improved protein expression and solubility.