A Spatial Model for Legislative Roll Call Analysis

A general nonlinear logit model is used to analyze political choice data. The model assumes probabilistic voting based on a spatial utility function. The parameters of the utility function and the spatial coordinates of the choices and the choosers can all be estimated on the basis of observed choices. Ordinary Guttman scaling is a degenerate case of this model. Estimation of the model is implemented in the NOMINATE program for one dimensional analysis of two alternative choices with no nonvoting. The robustness and face validity of the program outputs are evaluated on the basis of roll call voting data for the U.S. House and Senate. Extensive Monte Carlo studies are also presented. Substantive applications using the results for the Senate are briefly illustrated

The Polarization of American Politics

Elected officials in the United States appear to represent relatively extreme support coalitions rather than the interests of middle-of-the-road voters. This contention is supported by analysis of variance of liberal-conservative positions in the United States Senate from 1959 to 1980. Within both the Democratic and the Republican parties, there is considerable variation in liberal-conservative positions, but two senators from the same state and party tend to be very similar. In contrast, senators from the same state but from different parties are highly dissimilar, suggesting that each party represents an extreme support coalition in the state. Moreover, the distribution of senators is now consistent with the hypothesis that, in the long run, both parties have an equal chance of winning any seat in the Senate. This result suggests that there is now competition between equally balanced but extreme support coalitions throughout most of the United States

Ambition meets reality: Lessons from the taro boom in Nicaragua

Between 2006 and 2011, Nicaragua shipped an average of US$ 9.4 million per year of smallholder-produced fresh taro (Colocasia esculenta) to the United States; however, by 2016, the US market for Nicaraguan taro had effectively collapsed. We analyse the short-lived taro boom from the perspective of complex adaptive systems, showing how shocks, interactions between value chain actors, and lack of adaptive capacity among chain actors together contributed to the collapse of the chain. Primary data was collected from businesses and smallholders in 2010 and 2016 to understand the actors involved, their business relations, and the benefits and set backs they experienced along the way. The results show the capacity of better-off smallholders to engage in a demanding market, but also the struggles faced by more vulnerable smallholders to build new production systems and respond to internal and external shocks. Local businesses were generally unprepared for the uncertainties inherent in fresh horticultural trade or for engagement with distant buyers. Existing guides and tools for designing value chain interventions will benefit from greater attention to the circumstances of local actors and the challenges of building productive inter-business relations under higher levels of risk and uncertainty. Results demonstrate the need for a greater awareness of adaptive capacity within marketing systems that involve smallholders, a more critical look at the underlying assumptions of interventions for building these value chains, and the need for alternative planning scenarios, better risk mitigation and adaptation strategies. This case serves as a wake-up call for practitioners, donors, researchers and the private sector on how to identify market opportunities and the design of more robust strategies to respond to them

Recovering a Basic Space from Issue Scales in<i>R</i>

Basicspace is an R package that conducts Aldrich-McKelvey and Blackbox scaling to recover estimates of the underlying latent dimensions of issue scale data. We illustrate several applications of the package to survey data commonly used in the social sciences. Monte Carlo tests demonstrate that the procedure can recover latent dimensions and reproduce the matrix of responses at moderate levels of error and missing data

Analysis of wheat SAGE tags reveals evidence for widespread antisense transcription

BACKGROUND: Serial Analysis of Gene Expression (SAGE) is a powerful tool for genome-wide transcription studies. Unlike microarrays, it has the ability to detect novel forms of RNA such as alternatively spliced and antisense transcripts, without the need for prior knowledge of their existence. One limitation of using SAGE on an organism with a complex genome and lacking detailed sequence information, such as the hexaploid bread wheat Triticum aestivum, is accurate annotation of the tags generated. Without accurate annotation it is impossible to fully understand the dynamic processes involved in such complex polyploid organisms. Hence we have developed and utilised novel procedures to characterise, in detail, SAGE tags generated from the whole grain transcriptome of hexaploid wheat. RESULTS: Examination of 71,930 Long SAGE tags generated from six libraries derived from two wheat genotypes grown under two different conditions suggested that SAGE is a reliable and reproducible technique for use in studying the hexaploid wheat transcriptome. However, our results also showed that in poorly annotated and/or poorly sequenced genomes, such as hexaploid wheat, considerably more information can be extracted from SAGE data by carrying out a systematic analysis of both perfect and "fuzzy" (partially matched) tags. This detailed analysis of the SAGE data shows first that while there is evidence of alternative polyadenylation this appears to occur exclusively within the 3' untranslated regions. Secondly, we found no strong evidence for widespread alternative splicing in the developing wheat grain transcriptome. However, analysis of our SAGE data shows that antisense transcripts are probably widespread within the transcriptome and appear to be derived from numerous locations within the genome. Examination of antisense transcripts showing sequence similarity to the Puroindoline a and Puroindoline b genes suggests that such antisense transcripts might have a role in the regulation of gene expression. CONCLUSION: Our results indicate that the detailed analysis of transcriptome data, such as SAGE tags, is essential to understand fully the factors that regulate gene expression and that such analysis of the wheat grain transcriptome reveals that antisense transcripts maybe widespread and hence probably play a significant role in the regulation of gene expression during grain development

INVESTIGATIONS OF STORM WATER MANAGEMENT PROFESSIONALS\u27 PERCEPTIONS OF PERMEABLE INTERLOCKING CONCRETE PAVERS AS A STORMWATER MANAGEMENT OPTION

ABSTRACT This study examined stormwater management professionals\u27 perceptions of PICPs (Permeable Interlocking Concrete Pavement) as a stormwater management option to conventional curb and gutter methodology from years past. A self-administered survey questionnaire was developed as the primary research methodology. Three hundred stormwater management professionals were randomly selected as research subjects, and qualitative and quantitative methods were used to collect data for the study. Specific statistical gathering methods and tests for this study included: ex post facto experimental design, grounded theory design, correlation coefficients and ANOVA, and Pearson\u27s correlation coefficients. The survey found through quantitative analysis that although stormwater professionals have very little education on the topic of PICPs, they are very familiar with the benefits of this type pavement over more traditional types of surfacing. The hypothesis that stated PICPs were not well-utilized because stormwater professionals were not familiar with them was rejected and the reason for non-use appeared to be the perceived cost factor. The survey found through qualitative analysis the following major themes: The most common jobs among survey participants were stormwater administrators, project managers, and environmental engineers. Less runoff and perviousness were the biggest incentives to using PICPs. Cost and potential maintenance were the main deterrents to using PICPs. Reduced runoff, cost, and potential maintenance were the perceived main considerations of municipal governments with regards to PICP implementation. Poor - iii - design or installation, lack of knowledge, and inadequate maintenance are the biggest nuisances in reviewing PICP projects. Several practical recommendations were proposed in this study to overcome the barriers to using PICPs as a stormwater management tool, including more education of those involved in planning, designing, and implementing PICPs through workshops and training sessions, as well as more training for installers to provide decision makers a quality product from which to choose in the future. The most important aspect of education and training seemed to be the need to focus upon a better understanding of the actual long term costs and maintenance issues associated with PICPs

Pseudomonas Aeruginosa: Resistance to the Max

Pseudomonas aeruginosa is intrinsically resistant to a variety of antimicrobials and can develop resistance during anti-pseudomonal chemotherapy both of which compromise treatment of infections caused by this organism. Resistance to multiple classes of antimicrobials (multidrug resistance) in particular is increasingly common in P. aeruginosa, with a number of reports of pan-resistant isolates treatable with a single agent, colistin. Acquired resistance in this organism is multifactorial and attributable to chromosomal mutations and the acquisition of resistance genes via horizontal gene transfer. Mutational changes impacting resistance include upregulation of multidrug efflux systems to promote antimicrobial expulsion, derepression of ampC, AmpC alterations that expand the enzyme's substrate specificity (i.e., extended-spectrum AmpC), alterations to outer membrane permeability to limit antimicrobial entry and alterations to antimicrobial targets. Acquired mechanisms contributing to resistance in P. aeruginosa include β-lactamases, notably the extended-spectrum β-lactamases and the carbapenemases that hydrolyze most β-lactams, aminoglycoside-modifying enzymes, and 16S rRNA methylases that provide high-level pan-aminoglycoside resistance. The organism's propensity to grow in vivo as antimicrobial-tolerant biofilms and the occurrence of hypermutator strains that yield antimicrobial resistant mutants at higher frequency also compromise anti-pseudomonal chemotherapy. With limited therapeutic options and increasing resistance will the untreatable P. aeruginosa infection soon be upon us

The Statistical Analysis of Roll Call

We develop a Bayesian estimation procedure for spatial models of roll call voting. We show how a Bayesian approach to roll call analysis overcomes shortcomings and idiosyncracies of NOMINATE (some of which are not widely recognized). Our Bayesian approach (a) applies to any legislative setting, irrespective of size, legislative extremism, or the number of roll calls available for analysis; (b) provides a mechanism for directly incorporating auxiliary information as to the dimensionality of the underlying policy space, the identity of extremist legislators, key votes and the evolution of the legislative agenda; (c) lets us integrate measurement of legislative preferences with the analysis of those preferences. Notes to NEMP, May 2002 This paper sets out our ‘‘basic setup’ ’ (a Bayesian statistical operationalization of the Euclidean spatial voting model with roll call data), and constrasts it with the NOMINATE algorithms of Poole and Rosenthal. In the talk I will be considering extensions to our model, so as to accommodate and/or test conjectures in the literature on legislative politics (most prominently, the ‘‘party discipline’ ’ hypothesis, and conjectures about legislative responsiveness to constituency interests)