Manure microbial communities and resistance profiles reconfigure after transition to manure pits and differ from those in fertilized field soil

In agricultural settings, microbes and antimicrobial resistance genes (ARGs) have the potential to be transferred across diverse environments and ecosystems. The consequences of these microbial transfers are unclear and understudied. On dairy farms, the storage of cow manure in manure pits and subsequent application to field soil as a fertilizer may facilitate the spread of the mammalian gut microbiome and its associated ARGs to the environment. To determine the extent of both taxonomic and resistance similarity during these transitions, we collected fresh manure, manure from pits, and field soil across 15 different dairy farms for three consecutive seasons. We used a combination of shotgun metagenomic sequencing and functional metagenomics to quantitatively interrogate taxonomic and ARG compositional variation on farms. We found that as the microbiome transitions from fresh dairy cow manure to manure pits, microbial taxonomic compositions and resistance profiles experience distinct restructuring, including decreases in alpha diversity and shifts in specific ARG abundances that potentially correspond to fresh manure going from a gut-structured community to an environment-structured community. Further, we did not find evidence of shared microbial community or a transfer of ARGs between manure and field soil microbiomes. Our results suggest that fresh manure experiences a compositional change in manure pits during storage and that the storage of manure in manure pits does not result in a depletion of ARGs. We did not find evidence of taxonomic or ARG restructuring of soil microbiota with the application of manure to field soils, as soil communities remained resilient to manure-induced perturbation

The Critical Juncture Concept’s Evolving Capacity to Explain Policy Change

This article examines the evolution of our understanding of the critical junctures concept. The concept finds its origins in historical intuitionalism, being employed in the context of path dependence to account for sudden and jarring institutional or policy changes. We argue that the concept and the literature surrounding it—now incorporating ideas, discourse, and agency—have gradually become more comprehensive and nuanced as historical institutionalism was followed by ideational historical institutionalism and constructivist and discursive institutionalism. The prime position of contingency has been supplanted by the role of ideas and agency in explaining critical junctures and other instances of less than transformative change. Consequently, the concept is now capable of providing more comprehensive explanations for policy change

Leadership Strategies and Regime Change Under Authoritarianism: Government Performance and Supportbuilding in the Philippines.

This study argues that systemic approaches to authoritarianism do not offer a complete explanation of why authoritarian regimes collapse. A more satisfying explanation for why authoritarian regimes fall takes into account historical, international, and individual factors. This study focuses on the third factor, analyzing how the behavior of the leader will influence his tenure. The example of the Marcos regime in the Philippines is used to support the inclusion of individual factors in explaining regime collapse. This study shows that Marcos used two strategies to build his regime: centralization of political institutions and creation of a new political coalition. However, these strategies were unsuccessful in maintaining him in power; rather, they contributed to mass disaffection and the collapse of his regime. This study is based on fieldwork carried out in Manila from October 1983 to June 1984. Six case studies were chosen from three issue areas: appropriations, political reorganization, and the coconut industry. Seventy-one assemblymen and forty-one bureaucrats involved in the six cases were interviewed. Primary and secondary documents, including drafts of the bills and minutes from committee meetings and floor discussions were also consulted.Ph.D.Political scienceUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/161636/1/8801292.pd

Replication data for: Using Sequences to Model Crises

copy directly from abstract in PSRM publicatio

A Unified Approach to Measurement Error and Missing Data: Overview and Applications. Sociological Methods and Research

Abstract Although social scientists devote considerable effort to mitigating measurement error during data collection, they often ignore the issue during data analysis. And although many statistical methods have been proposed for reducing measurement error-induced biases, few have been widely used because of implausible assumptions, high levels of model dependence, difficult computation, or inapplicability with multiple mismeasured variables. We develop an easy-to-use alternative without these problems; it generalizes the popular multiple imputation (mi) framework by treating missing data problems as a limiting special case of extreme measurement error, and corrects for both. Like mi, the proposed framework is a simple two-step procedure, so that in the second step researchers can use whatever statistical method they would have if there had been no problem in the first place. We also offer empirical illustrations, open source software that implements all the methods described herein, and a companion paper with technical details and extension