An Emerging Picture of Neoproterozoic Ocean Chemistry: Insights from the Chuar Group, Grand Canyon, USA

Detailed iron, sulfur and carbon chemistry through the > 742 million year old ChuarGroup reveals a marine basin dominated by anoxic and ferrous iron-rich (ferruginous) bottom waters punctuated, late in the basin's development, by an intrusion of sulfide-rich (euxinic) conditions. The observation that anoxia occurred frequently in even the shallowest of Chuar environments (10s of meters or less) suggests that global atmospheric oxygen levels were significantly lower than today. In contrast, the transition from ferruginous to euxinic subsurface water is interpreted to reflect basinal control—specifically, increased export of organic carbon from surface waters. Low fluxes of organic carbon into subsurface water masses should have been insufficient to deplete oxygen via aerobic respiration, resulting in an oxic oxygen minimum zone (OMZ). Where iron was available, larger organic carbon fluxes should have depleted oxygen and facilitated anaerobic respiration using ferric iron as the oxidant, with iron carbonate as the expected mineralogical signature in basinal shale. Even higher organic fluxes would, in turn, have depleted ferric iron and up-regulated anaerobic respiration by sulfate reduction, reflected in high pyrite abundances. Observations from the ChuarGroup are consistent with these hypotheses, and gain further support from pyrite and sulfate sulfur isotope abundances. In general, Chuar data support the hypothesis that ferruginous subsurface waters returned to the oceans, replacing euxinia, well before the Ediacaran emergence of persistently oxygenated conditions, and even predating the Sturtian glaciation. Moreover, our data suggest that the reprise of ferruginous water masses may relate to widespread rifting during the break-up of Rodinia. This environmental transition, in turn, correlates with both microfossil and biomarker evidence for an expanding eukaryotic presence in the oceans, suggesting a physiologically mediated link among tectonics, environmental chemistry and life in the dynamic Neoproterozoic Earth system.Earth and Planetary Science

Devonian Rise in Atmospheric Oxygen Correlated to the Radiations of Terrestrial Plants and Large Predatory Fish

The evolution of Earth’s biota is intimately linked to the oxygenation of the oceans and atmosphere. We use the isotopic composition and concentration of molybdenum (Mo) in sedimentary rocks to explore this relationship. Our results indicate two episodes of global ocean oxygenation. The first coincides with the emergence of the Ediacaran fauna, including large, motile bilaterian animals, ca. 550-560 million year ago (Ma), reinforcing previous geochemical indications that Earth surface oxygenation facilitated this radiation. The second, perhaps larger, oxygenation took place around 400 Ma, well after the initial rise of animals and, therefore, suggesting that early metazoans evolved in a relatively low oxygen environment. This later oxygenation correlates with the diversification of vascular plants, which likely contributed to increased oxygenation through the enhanced burial of organic carbon in sediments. It also correlates with a pronounced radiation of large predatory fish, animals with high oxygen demand. We thereby couple the redox history of the atmosphere and oceans to major events in animal evolution.Earth and Planetary SciencesOrganismic and Evolutionary Biolog

Two sword lengths apart: Credible commitment problems and physical violence in democratic national legislatures

Ideally, national legislatures in democracies should be venues for peacefully resolving conflicts between opposing groups. However, they can become places of physical violence. Such violence can be an indication that countries’ legislative institutions are functioning far from the democratic ideal of being venues for peaceful conflict reconciliation. In some cases, such as Ukraine prior to the 2014 outbreak of armed conflict in the country’s east and south, violence can indicate and possibly fuel deeper political divisions. In this first global study of legislative violence, I show that brawls are more likely when legislators find it difficult to credibly commit to follow peaceful bargains. Credible commitment problems are more acute in countries with new democracies and disproportionate electoral outcomes – that is, when electoral votes for parties do not closely correspond to the legislative seats they are given. I find robust support for this argument by first examining a case study of legislative violence in the antebellum United States Senate. Pro- and anti-slavery senators became increasingly unable to maintain credible commitments in the lead-up to the 1856 caning of Senator Charles Sumner as the allocation of seats in the legislative body became more disproportional. Second, I find further support for my argument in a new global dataset of contemporary instances of violence in national legislatures. In addition, I find strong evidence that violence is more likely in legislatures with small minority governments. Despite reasonable expectations, civil wars are not associated with more legislative violence

学会抄録

Canonical pathways enrichment calculated by Ingenuity Pathway Analysis. A total of 46 pathways were detected as significantly enriched with genes differentially expressed in the pairwise comparisons indicated in the first row of the table (P < 0.05). First column on the left indicates Gene Ontology name associated with the canonical pathway. Log10P values are reported for each pathway. (XLS 38 kb

Products as Affective Modifiers of Identities

© The Author(s) 2015. Are salesclerks seen as better, more powerful, or more active when they drive Mustangs? What about entrepreneurs? What about driving a mid-sized car? Intuitively, we have ideas about these, but much of the research on the affective nature of products is on purchasing, desires, and self-fulfillment. Drawing on symbolic interactionism, we argue that people's association with products has some basis in the impression management of their identity. For this to occur, there must be some cultural consensus about the way that products modify identities. Drawing on affect control theory's (ACT) methodology and equations, we measure the goodness, powerfulness, and activeness of several products, identities, and the associated product-modified identities to explore how products function as affective modifiers of identities. We find consistent effects across several types of technology products, whereby products pull the modified identity in the direction of the products' affective qualities. Support is established for the ACT equations that predict how traits modify identities as also having utility for predicting how products modify identities. This suggests that the opening questions can be answered empirically by measuring cultural-specific sentiments of the identity and the product and by developing equations to predict the identity modification process

‘Dominant ethnicity’ and the ‘ethnic-civic’ dichotomy in the work of A. D. Smith

This article considers the way in which the work of Anthony Smith has helped to structure debates surrounding the role of ethnicity in present-day nations. Two major lines of enquiry are evident here. First, the contemporary role of dominant ethnic groups within 'their' nations and second, the interplay between ethnic and civic elements in nationalist argument. The two processes are related, but maintain elements of distinctiveness. Smith's major contribution to the dominant ethnicity debate has been to disembed ethnicity from the ideologically-charged and/or anglo-centric discourse of ethnic relations and to place it in historical context, thereby opening up space for dominant group ethnicity to be considered as a distinct phenomenon. This said, Smith's work does not adequately account for the vicissitudes of dominant ethnicity in the contemporary West. Building on the classical works of Hans Kohn and Friedrich Meinecke, Anthony Smith has also made a seminal contribution to the debate on civic and ethnic forms of national identity and nationalist ideology. As well as freeing this debate from the strong normative overtones which it has often carried, he has continued to insist that the terms civic and ethnic should be treated as an ideal-typical distinction rather than a scheme of classification

Evaluation Research and Institutional Pressures: Challenges in Public-Nonprofit Contracting

This article examines the connection between program evaluation research and decision-making by public managers. Drawing on neo-institutional theory, a framework is presented for diagnosing the pressures and conditions that lead alternatively toward or away the rational use of evaluation research. Three cases of public-nonprofit contracting for the delivery of major programs are presented to clarify the way coercive, mimetic, and normative pressures interfere with a sound connection being made between research and implementation. The article concludes by considering how public managers can respond to the isomorphic pressures in their environment that make it hard to act on data relating to program performance.This publication is Hauser Center Working Paper No. 23. The Hauser Center Working Paper Series was launched during the summer of 2000. The Series enables the Hauser Center to share with a broad audience important works-in-progress written by Hauser Center scholars and researchers

The Linkage Between Neighborhood and Voluntary Association Patterns: a Comparison of Black and White Urban Populations

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68314/2/10.1177_089976407400300201.pd