McMaster University

About: McMaster University is a education organization based out in Hamilton, Ontario, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 41361 authors who have published 101269 publications receiving 4251422 citations.

Concreteness ratings for 40 thousand generally known English word lemmas

Abstract: Concreteness ratings are presented for 37,058 English words and 2,896 two-word expressions (such as zebra crossing and zoom in), obtained from over 4,000 participants by means of a norming study using Internet crowdsourcing for data collection. Although the instructions stressed that the assessment of word concreteness would be based on experiences involving all senses and motor responses, a comparison with the existing concreteness norms indicates that participants, as before, largely focused on visual and haptic experiences. The reported data set is a subset of a comprehensive list of English lemmas and contains all lemmas known by at least 85 % of the raters. It can be used in future research as a reference list of generally known English lemmas.

A Model of Political Competition with Citizen-Candidates

Abstract: The authors develop a model of electoral competition in which citizens choose whether or not to run as candidates. A winner implements her favorite policy. The equilibrium number of candidates depends negatively on the cost of running and positively on the benefits of winning. For some parameter values, all equilibria under plurality rule have exactly two candidates, whose positions are distinct. Two-candidate elections are more likely under plurality rule than under a runoff system. The candidates' positions are less differentiated under a runoff system. There exist equilibria under both systems in which some candidates have no chance of winning.

What would it take for renewably powered electrosynthesis to displace petrochemical processes

Abstract: Electrocatalytic transformation of carbon dioxide (CO2) and water into chemical feedstocks offers the potential to reduce carbon emissions by shifting the chemical industry away from fossil fuel dependence. We provide a technoeconomic and carbon emission analysis of possible products, offering targets that would need to be met for economically compelling industrial implementation to be achieved. We also provide a comparison of the projected costs and CO2 emissions across electrocatalytic, biocatalytic, and fossil fuel-derived production of chemical feedstocks. We find that for electrosynthesis to become competitive with fossil fuel-derived feedstocks, electrical-to-chemical conversion efficiencies need to reach at least 60%, and renewable electricity prices need to fall below 4 cents per kilowatt-hour. We discuss the possibility of combining electro- and biocatalytic processes, using sequential upgrading of CO2 as a representative case. We describe the technical challenges and economic barriers to marketable electrosynthesized chemicals.

Do practice guidelines guide practice? The effect of a consensus statement on the practice of physicians.

Abstract: Guidelines for medical practice can contribute to improved care only if they succeed in moving actual practice closer to the behaviors the guidelines recommend. To assess the effect of such guidelines, we surveyed hospitals and obstetricians in Ontario before and after the release of a widely distributed and nationally endorsed consensus statement recommending decreases in the use of cesarean sections. These surveys, along with discharge data from hospitals reflecting actual practice, revealed that most obstetricians (87 to 94 percent) were aware of the guidelines and that most (82.5 to 85 percent) agreed with them. Attitudes toward the use of cesarean section were congruent with the recommendations even before their release. One third of the hospitals and obstetricians reported changing their practice as a consequence of the guidelines, and obstetricians reported rates of cesarean section in women with a previous cesarean section that were significantly reduced, in keeping with the recommendations (from 72.2 percent to 61.1 percent; P less than 0.01). The surveys also showed, however, that knowledge of the content of the recommendations was poor (67 percent correct responses). Furthermore, data on actual practice after the publication of the guidelines showed that the rates of cesarean section were 15 to 49 percent higher than the rates reported by obstetricians, and they showed only a slight change from the previous upward trend. We conclude that guidelines for practice may predispose physicians to consider changing their behavior, but that unless there are other incentives or the removal of disincentives, guidelines may be unlikely to effect rapid change in actual practice. We believe that incentives should operate at the local level, although they may include system-wide economic changes.

Emerging threats and persistent conservation challenges for freshwater biodiversity

Abstract: In the 12 years since Dudgeon et al. (2006) reviewed major pressures on freshwater ecosystems, the biodiversity crisis in the world’s lakes, reservoirs, rivers, streams and wetlands has deepened. While lakes, reservoirs and rivers cover only 2.3% of the Earth’s surface, these ecosystems host at least 9.5% of the Earth’s described animal species. Furthermore, using the World Wide Fund for Nature’s Living Planet Index, freshwater population declines (83% between 1970 and 2014) continue to outpace contemporaneous declines in marine or terrestrial systems. The Anthropocene has brought multiple new and varied threats that disproportionately impact freshwater systems. We document 12 emerging threats to freshwater biodiversity that are either entirely new since 2006 or have since intensified: (i) changing climates; (ii) e-commerce and invasions; (iii) infectious diseases; (iv) harmful algal blooms; (v) expanding hydropower; (vi) emerging contaminants; (vii) engineered nanomaterials; (viii) microplastic pollution; (ix) light and noise; (x) freshwater salinisation; (xi) declining calcium; and (xii) cumulative stressors. Effects are evidenced for amphibians, fishes, invertebrates, microbes, plants, turtles and waterbirds, with potential for ecosystem-level changes through bottom-up and top-down processes. In our highly uncertain future, the net effects of these threats raise serious concerns for freshwater ecosystems. However, we also highlight opportunities for conservation gains as a result of novel management tools (e.g. environmental flows, environmental DNA) and specific conservation-oriented actions (e.g. dam removal, habitat protection policies,managed relocation of species) that have been met with varying levels of success.Moving forward, we advocate hybrid approaches that manage fresh waters as crucial ecosystems for human life support as well as essential hotspots of biodiversity and ecological function. Efforts to reverse global trends in freshwater degradation now depend on bridging an immense gap between the aspirations of conservation biologists and the accelerating rate of species endangerment.