Workload, Risks, and Goal Framing as Antecedents of Shortcut Behaviors

The final publication is available at Springer via: http://dx.doi.org/10.1007/s10869-016-9450-0Purpose: Shortcut behaviors are methods of completing a task that require less time than typical or standard procedures. These behaviors carry the benefit of increasing efficiency, yet can also carry risks (e.g., of an accident). The purpose of this research is to understand the reasons individuals engage in shortcut behaviors, even when doing so is known to be risky. Design/Methodology/Approach: We present two laboratory studies (N = 121 and N = 144) in which participants performed an air traffic control simulation. Participants could improve efficiency by taking shortcuts; that is, by sending aircraft off the prescribed flight paths. This design allowed for direct and unobtrusive observation of shortcut behaviors. Findings: Individuals who were told that efficiency was an obligation tended to believe that shortcut behaviors had utility for managing high workloads, even when the risks associated with shortcuts were high. Downstream, utility perceptions were positively related to actual shortcut behavior. Implications: Although communicating risks may be used to help individuals balance the “pros” and “cons” of shortcut behaviors, goal framing is also important. Subtle cues indicating that efficiency is an obligation can lead to elevated perceptions of the utility of shortcut behaviors, even when knowing that engaging in shortcut behaviors is very risky. Originality/Value: Past research has provided limited insights into the reasons individuals sometimes engage in shortcut behaviors even when doing so is known to be risky. The current research speaks to this issue by identifying workload and obligation framing as antecedents of the decision to take shortcuts.Social Sciences and Humanities Research Council of Canada Grant [SSHRC #435-2014-1263

Prospectus, 14, 2007

https://spark.parkland.edu/prospectus_2007/1004/thumbnail.jp

Trophic roles of tadpoles in tropical Australian streams

Tadpoles can be abundant consumers in stream ecosystems, and may influence the structure and function of streams through their feeding activities and interactions with other organisms. To understand the contribution of tadpoles to stream functioning, and the potential impact of their loss, it is necessary to determine their diets and how they might influence food-web structure. Using gut-content analysis and stable-isotope analysis of N and C, we determined the main food sources and trophic positions of tadpoles of five native frog species, invertebrates, and fish in upland and lowland Australian Wet Tropics streams. Omnivory was prevalent among the tadpoles and invertebrates. Tadpoles consumed different food according to availability and nutrient quality, but assimilated mainly biofilm and algae. Most tadpoles and invertebrates assimilated the same high-quality foods. Food webs in upland riffles were simplified by local extinction of tadpoles, and were probably simplified in pools in the cooler months by seasonal decline in tadpole abundance. Food-web complexity was increased in some pools by the presence of predatory fish and a greater number of basal sources. As tadpoles are important seasonal components in stream food webs, their local extinction can greatly alter food-web structure and complexity and, possibly, processes such as leaf litter breakdown and sediment accumulation

A Composite Seyfert 2 X-ray Spectrum: Implications for the Origin of the Cosmic X-ray Background

We present a composite 1-10 keV Seyfert 2 X-ray spectrum, derived from ASCA observations of a distance-limited sample of nearby galaxies. All 29 observed objects were detected. Above ~3 keV, the composite spectrum is inverted, confirming that Seyfert 2 galaxies as a class have the spectral properties necessary to explain the flat shape of the cosmic X-ray background spectrum. Integrating the composite spectrum over redshift, we find that the total emission from Seyfert 2 galaxies, combined with the expected contribution from unabsorbed type 1 objects, provides an excellent match to the spectrum and intensity of the hard X-ray background. The principal uncertainty in this procedure is the cosmic evolution of the Seyfert 2 X-ray luminosity function. Separate composite spectra for objects in our sample with and without polarized broad optical emission lines are also presented.Comment: 11 pages (AASTeX), including 3 figures. Accepted for publication in ApJ Letter

Sequential conformational rearrangements in flavivirus membrane fusion

The West Nile Virus (WNV) envelope protein, E, promotes membrane fusion during viral cell entry by undergoing a low-pH triggered conformational reorganization. We have examined the mechanism of WNV fusion and sought evidence for potential intermediates during the conformational transition by following hemifusion of WNV virus-like particles (VLPs) in a single particle format. We have introduced specific mutations into E, to relate their influence on fusion kinetics to structural features of the protein. At the level of individual E subunits, trimer formation and membrane engagement of the threefold clustered fusion loops are rate-limiting. Hemifusion requires at least two adjacent trimers. Simulation of the kinetics indicates that availability of competent monomers within the contact zone between virus and target membrane makes trimerization a bottleneck in hemifusion. We discuss the implications of the model we have derived for mechanisms of membrane fusion in other contexts. DOI: http://dx.doi.org/10.7554/eLife.04389.00

Twenty-Four-Month Longitudinal Study Suggests Little to No Horizontal Gene Transfer In Situ between Third-Generation Cephalosporin-Resistant \u3ci\u3eSalmonella\u3c/i\u3e and Third-Generation Cephalosporin-Resistant \u3ci\u3eEscherichia coli\u3c/i\u3e in a Beef Cattle Feedyard

Third-generation cephalosporins (3GCs) are preferred treatments for serious human Salmonella enterica infections. Beef cattle are suspected to contribute to human 3GC-resistant Salmonella infections. Commensal 3GC-resistant Escherichia coli are thought to act as reservoirs of 3GC resistance because these strains are isolated more frequently than are 3GC-resistant Salmonella strains at beef cattle feedyards. During each of 24 consecutive months, four samples of pen surface material were obtained from five pens (N = 480) at a Nebraska feedyard to determine to the contribution of 3GC-resistant E. coli to the occurrence of 3GC-resistant Salmonella. Illumina whole genome sequencing was performed, and susceptibility to 14 antimicrobial agents was determined for 121 3GC-susceptible Salmonella, 121 3GC-resistant Salmonella, and 203 3GCresistant E. coli isolates. 3GC-susceptible Salmonella isolates were predominantly from serotypes Muenchen (70.2%) and Montevideo clade 1 (23.1%). 3GC-resistant Salmonella isolates were predominantly from serotypes Montevideo clade 2 (84.3%). One bla gene type (blaCMY-2) and the IncC plasmid replicon were present in 100 and 97.5% of the 3GC-resistant Salmonella, respectively. Eleven bla gene types were detected in the 3GC-resistant E. coli, which were distributed across 42 multilocus sequence types. The blaCMY-2 gene and IncC plasmid replicon were present in 37.9 and 9.9% of the 3GC-resistant E. coli, respectively. These results suggest that 3GC resistance in Salmonella was primarily due the persistence of Salmonella Montevideo clade 2 with very minimal or no contribution from 3GC-resistant E. coli via horizontal gene transfer and that 3GCresistant E. coli may not be a useful indicator for 3GC-resistant Salmonella in beef cattle production environments

Prospectus, January 17, 2007

https://spark.parkland.edu/prospectus_2007/1000/thumbnail.jp

Gain-of-Sensitivity Mutations in a Trim5-Resistant Primary Isolate of Pathogenic SIV Identify Two Independent Conserved Determinants of Trim5α Specificity

Retroviral capsid recognition by Trim5 blocks productive infection. Rhesus macaques harbor three functionally distinct Trim5 alleles: Trim5αQ, Trim5αTFP and Trim5CypA. Despite the high degree of amino acid identity between Trim5αQ and Trim5αTFP alleles, the Q/TFP polymorphism results in the differential restriction of some primate lentiviruses, suggesting these alleles differ in how they engage these capsids. Simian immunodeficiency virus of rhesus macaques (SIVmac) evolved to resist all three alleles. Thus, SIVmac provides a unique opportunity to study a virus in the context of the Trim5 repertoire that drove its evolution in vivo. We exploited the evolved rhesus Trim5α resistance of this capsid to identify gain-of-sensitivity mutations that distinguish targets between the Trim5αQ and Trim5αTFP alleles. While both alleles recognize the capsid surface, Trim5αQ and Trim5αTFP alleles differed in their ability to restrict a panel of capsid chimeras and single amino acid substitutions. When mapped onto the structure of the SIVmac239 capsid N-terminal domain, single amino acid substitutions affecting both alleles mapped to the β-hairpin. Given that none of the substitutions affected Trim5αQ alone, and the fact that the β-hairpin is conserved among retroviral capsids, we propose that the β-hairpin is a molecular pattern widely exploited by Trim5α proteins. Mutations specifically affecting rhesus Trim5αTFP (without affecting Trim5αQ) surround a site of conservation unique to primate lentiviruses, overlapping the CPSF6 binding site. We believe targeting this site is an evolutionary innovation driven specifically by the emergence of primate lentiviruses in Africa during the last 12 million years. This modularity in targeting may be a general feature of Trim5 evolution, permitting different regions of the PRYSPRY domain to evolve independent interactions with capsid

Prospectus, December 6, 2006

https://spark.parkland.edu/prospectus_2006/1029/thumbnail.jp

Changes in the gut microbiome and fermentation products concurrent with enhanced longevity in acarbose-treated mice.

BACKGROUND: Treatment with the α-glucosidase inhibitor acarbose increases median lifespan by approximately 20% in male mice and 5% in females. This longevity extension differs from dietary restriction based on a number of features, including the relatively small effects on weight and the sex-specificity of the lifespan effect. By inhibiting host digestion, acarbose increases the flux of starch to the lower digestive system, resulting in changes to the gut microbiota and their fermentation products. Given the documented health benefits of short-chain fatty acids (SCFAs), the dominant products of starch fermentation by gut bacteria, this secondary effect of acarbose could contribute to increased longevity in mice. To explore this hypothesis, we compared the fecal microbiome of mice treated with acarbose to control mice at three independent study sites. RESULTS: Microbial communities and the concentrations of SCFAs in the feces of mice treated with acarbose were notably different from those of control mice. At all three study sites, the bloom of a single bacterial taxon was the most obvious response to acarbose treatment. The blooming populations were classified to the largely uncultured Bacteroidales family Muribaculaceae and were the same taxonomic unit at two of the three sites. Propionate concentrations in feces were consistently elevated in treated mice, while the concentrations of acetate and butyrate reflected a dependence on study site. Across all samples, Muribaculaceae abundance was strongly correlated with propionate and community composition was an important predictor of SCFA concentrations. Cox proportional hazards regression showed that the fecal concentrations of acetate, butyrate, and propionate were, together, predictive of mouse longevity even while controlling for sex, site, and acarbose. CONCLUSION: We observed a correlation between fecal SCFAs and lifespan in mice, suggesting a role of the gut microbiota in the longevity-enhancing properties of acarbose. Treatment modulated the taxonomic composition and fermentation products of the gut microbiome, while the site-dependence of the responses illustrate the challenges facing reproducibility and interpretation in microbiome studies. These results motivate future studies exploring manipulation of the gut microbial community and its fermentation products for increased longevity, testing causal roles of SCFAs in the observed effects of acarbose