Perching but not foraging networks predict the spread of novel foraging skills in starlings

The directed social learning hypothesis suggests that information does not spread evenly through animal groups, but rather individual characteristics and patterns of physical proximity guide the social transmission of information along specific pathways. Network-based diffusion analysis (NBDA) allows researchers to test whether information spreads following a social network. However, the explanatory power of different social networks has rarely been compared, and current models do not easily accommodate random effects (e.g. allowing for individuals within groups to correlate in their asocial solving rates). We tested whether the spread of two novel foraging skills through captive starling groups was affected by individual- and group-level random and fixed effects (i.e. sex, age, body condition, dominance rank and demonstrator status) and perching or foraging networks. We extended NBDA to include random effects and conducted model discrimination in a Bayesian context. We found that social learning increased the rate at which birds acquired the novel foraging task solutions by 6.67 times, and acquiring one of the two novel foraging task solutions facilitated the asocial acquisition of the other. Surprisingly, the spread of task solutions followed the perching rather than the foraging social network. Upon acquiring a task solution, foraging performance was facilitated by the presence of group mates. Our results highlight the importance of considering more than one social network when predicting the spread of information through animal groups. This article is part of a Special Issue entitled: Cognition in the wild

College persistence: A comparative analysis across conventional and less-common cohorts

Historically, calculation of college student retention by colleges, state agencies, and the federal government has been based on tracking enrollment and attrition of an 18- to 24-year old population of first-time full-time students in a fall-to-fall pattern. Use of this “native cohort” assumes that students enroll in college on a full-time basis immediately following high school graduation and proceed on an unbroken progression toward a bachelor\u27s degree. College attendance patterns have changed substantially, however, so that use of this native cohort no longer accurately reflects student persistence, particularly for institutions with a substantial proportion of non-traditional students (e.g., transfers, part-time, or adult-status).^ Using a sample of 9,029 students enrolled over a seven-year period, this study examined differences between persistence outcomes for four student cohorts at a public liberal arts university (a) full-time, first-time students (“native” cohort), (b) full-time, transfer students, (c) part-time, first-time students, and (d) part-time, transfer students. Persistence was defined by a ratio algorithm that summed the number of semesters each student was enrolled for at least one credit divided by the total number of semesters of availability. Any student who graduated received a persistence score of 1.0. Across all four enrollment groupings, the persistence ratio averaged .69; full-time, transfer students were most likely to persist (M ratio = .74) and part-time, first-time students were least likely to persist (M ratio = .57). These differences remained highly significant after other potential influences on student success (e.g., GPA after first year, SAT scores) were covaried out. These differential outcomes also were similar for men and women and for students who reported having at least one parent who had obtained a college degree versus those whose parents had not completed college. Prediction of persistence from multiple student-input and college-environment variables yielded beta coefficients that were generally similar across the four cohorts.

A Texas Peasantry? Black Smallholders in the Texas Sugar Bowl, 1865–1890

This article examines a small community of former slaves in Texas's leading sugar-producing county and argues that local conditions fostered the growth of a Caribbean-style ‘reconstituted peasantry’. Using local sources to compile a database of 79 African American landowners, it traces the postwar decline of the sugar plantations, the process of black land acquisition and the smallholders' strategies for survival. The smallholders' position, however, was precarious, and most lost their lands at the close of the nineteenth century. The piece concludes by suggesting that more intensive local research into former-slave communities may force a reconsideration of the notion that all American slaves became landless wage labourers. © 2007 Taylor & Francis

Expression quantitative trait locus fine mapping of the 17q12–21 asthma locus in African American children: a genetic association and gene expression study

Background: African ancestry is associated with a higher prevalence and greater severity of asthma than European ancestries, yet genetic studies of the most common locus associated with childhood-onset asthma, 17q12–21, in African Americans have been inconclusive. The aim of this study was to leverage both the phenotyping of the Children's Respiratory and Environmental Workgroup (CREW) birth cohort consortium, and the reduced linkage disequilibrium in African Americans, to fine map the 17q12–21 locus. Methods: We first did a genetic association study and meta-analysis using 17q12–21 tag single-nucleotide polymorphisms (SNPs) for childhood-onset asthma in 1613 European American and 870 African American children from the CREW consortium. Nine tag SNPs were selected based on linkage disequilibrium patterns at 17q12–21 and their association with asthma, considering the effect allele under an additive model (0, 1, or 2 effect alleles). Results were meta-analysed with publicly available summary data from the EVE consortium (on 4303 European American and 3034 African American individuals) for seven of the nine SNPs of interest. Subsequently, we tested for expression quantitative trait loci (eQTLs) among the SNPs associated with childhood-onset asthma and the expression of 17q12–21 genes in resting peripheral blood mononuclear cells (PBMCs) from 85 African American CREW children and in upper airway epithelial cells from 246 African American CREW children; and in lower airway epithelial cells from 44 European American and 72 African American adults from a case-control study of asthma genetic risk in Chicago (IL, USA). Findings: 17q12–21 SNPs were broadly associated with asthma in European Americans. Only two SNPs (rs2305480 in gasdermin-B [GSDMB] and rs8076131 in ORMDL sphingolipid biosynthesis regulator 3 [ORMDL3]) were associated with asthma in African Americans, at a Bonferroni-corrected threshold of p<0·0055 (for rs2305480_G, odds ratio [OR] 1·36 [95% CI 1·12–1·65], p=0·0014; and for rs8076131_A, OR 1·37 [1·13–1·67], p=0·0010). In upper airway epithelial cells from African American children, genotype at rs2305480 was the most significant eQTL for GSDMB (eQTL effect size [β] 1·35 [95% CI 1·25–1·46], p<0·0001), and to a lesser extent showed an eQTL effect for post-GPI attachment to proteins phospholipase 3 (β 1·15 [1·08–1·22], p<0·0001). No SNPs were eQTLs for ORMDL3. By contrast, in PBMCs, the five core SNPs were associated only with expression of GSDMB and ORMDL3. Genotype at rs12936231 (in zona pellucida binding protein 2) showed the strongest associations across both genes (for GSDMB, eQTLβ 1·24 [1·15–1·32], p<0·0001; and for ORMDL3 (β 1·19 [1·12–1·24], p<0·0001). The eQTL effects of rs2305480 on GSDMB expression were replicated in lower airway cells from African American adults (β 1·29 [1·15–1·44], p<0·0001). Interpretation: Our study suggests that SNPs regulating GSDMB expression in airway epithelial cells have a major role in childhood-onset asthma, whereas SNPs regulating the expression levels of 17q12–21 genes in resting blood cells are not central to asthma risk. Our genetic and gene expression data in African Americans and European Americans indicated GSDMB to be the leading candidate gene at this important asthma locus.6 month embargo; published: 01 May 2020This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]