Situating Politics: Spatial Heterogeneity and the Study of Political History

While quantitative methods are routinely used to examine historical materials, critics take issue with the use of global regression models that attach a single parameter to each predictor, thereby ignoring the effects of time and space, which together define the context in which historical events unfold. This problem can be addressed by allowing for parameter heterogeneity, as highlighted by the proliferation of work on the use of time-varying parameter models. In this paper, I show how this approach can be extended to the case of spatial data using spatially-varying coefficient models, with an eye toward the study of electoral politics, where the use of spatial data is especially common in historical settings. Toward this end, I revisit a critical case in the field of quantitative history: the rise of electoral Populism in the American West in the period between 1890 and 1896. Upending popular narratives about the correlates of third- party support in the late nineteenth century, I show that the association between third- party vote share and traditional predictors such as economic hardship and ethnic composition varied considerably from one place to the next, giving rise to distinct varieties of electoral Populism—a finding that is missed by global models, which mistake the mathematically particular for the historically general. These findings have important theoretical and empirical implications for the study of political action in a world where parameter heterogeneity is increasingly recognized as a standard feature of modern social science.

Random heterogeneity outperforms design in network synchronization

A widely held assumption on network dynamics is that similar components are more likely to exhibit similar behavior than dissimilar ones and that generic differences among them are necessarily detrimental to synchronization. Here, we show that this assumption does not generally hold in oscillator networks when communication delays are present. We demonstrate, in particular, that random parameter heterogeneity among oscillators can consistently rescue the system from losing synchrony. This finding is supported by electrochemical-oscillator experiments performed on a multielectrode array network. Remarkably, at intermediate levels of heterogeneity, random mismatches are more effective in promoting synchronization than parameter assignments specifically designed to facilitate identical synchronization. Our results suggest that, rather than being eliminated or ignored, intrinsic disorder in technological and biological systems can be harnessed to help maintain coherence required for function.

Growth Econometrics

Growth econometrics is the application of statistical methods to the study of economic growth and levels of national output or income per head. Researchers often seek to understand why growth rates differ across countries. The field developed rapidly in the 1980s and 1990s, but the early work often proved fragile. Cross-section analyses are limited by the relatively small number of countries in the world and problems of endogeneity, parameter heterogeneity, model uncertainty, and cross-section error dependence. The long-term prospects look better for approaches using panel data. Overall, the quality of the evidence has improved over time, due to better measurement, more data, and new methods. As longer spans of data become available, the methods of growth econometrics will shed light on fundamental questions that are hard to answer any other way.

The Impact of Global Value Chain Participation on Sectoral Growth and Productivity

This study investigates the impact of participation in global value chains (GVCs) on sectoral value-added and total factor productivity growth (TFP) for two different time periods of 1995–2011 and 2005–2015. In addition to the commonly used participation indices, we also calculate lesser known measures of backward and forward participation indices, as suggested by the OECD. Our Generalized Method of Moments (GMM) estimations for the full sample indicate that sectors with higher GVC participation experience much higher output and TFP growth, especially for the period 1995–2011. Overall, our results imply that there have been decreasing gains from GVC participation in the later period. Note that our estimates for both output and TFP growth are very much similar. This means that participation in GVCs promotes not only output growth but also productivity growth across sectors. Considering the parameter heterogeneity, we repeat our estimations for manufacturing and services separately. Although for the earlier period both the manufacturing and services sectors benefit from more participation in terms of higher output and productivity growth, only the manufacturing sector experiences higher productivity growth from more participation for the period 2005–2015. Relatively less significant and smaller estimates for the later period covering the latest global crisis imply that participation in GVCs fails to bring satisfactory gains to countries and sectors.

Use of radiobiology in medical jurisprudence, with particular reference to delays in diagnosis and therapeutic onset

Objective: This paper considers aspects of radiobiology and cell and tissue kinetics applicable to legal disputations concerned with diagnostic and treatment onset delays. Methods: Various models for tumour volume changes with time are reviewed for estimating volume ranges at earlier times, using ranges of kinetic parameters. Statistical cure probability methods, using Poisson statistics with allowances for parameter heterogeneity, are also described to estimate the significance of treatment delays, as well as biological effective dose (BED) estimations of radiation effectiveness. Results: The use of growth curves, based on parameters in the literature but with extended ranges, can identify a window of earlier times when such tumour volumes would be amenable to a cure based on the literature for curability with stage (and dimensions). Also, where tumour dimensions are not available in a post-operative setting, higher cure probabilities can be achieved if treatment had been given at earlier times. Conclusion: The use of radiobiological modelling can provide useful insights, with quantitative assessments of probable prior conditions and future outcomes, and thus be of assistance to a Court in deciding the most correct judgement. Advances in knowledge: This study collates prior knowledge about aspects of radiobiology that can be useful in the accumulation of sufficient proof within medicolegal claims involving diagnostic and treatment days.

Demand Response Using Heterogeneous Thermostatically Controlled Loads: Characterization of Aggregate Power Dynamics

This article presents an analysis of the damping and beating effects within the aggregate power demand of heterogeneous thermostatically controlled loads (TCLs). Demand response using TCLs is an appealing method to enable higher levels of penetration of intermittent renewable resources into the electric grid. Previous literature covers the benefits of TCL population heterogeneity for control purposes, but the focus is solely on the damping observed in these systems. This work, in contrast, characterizes the combined damping and beating effects in the power demand for different types of TCL parameter heterogeneity. The forced aggregate dynamics of TCLs have been shown to be bilinear when set point temperature adjustment is used as a control input. This motivates the article's use of free response dynamics, which are linear, to characterize both the damping and beating phenomena. A stochastic parameter distribution is applied to the homogeneous power demand solution, furnishing an analytic expression for the aggregate power demand. The time-varying damping ratios of this reduced-order model characterize the damping in the system. By analyzing a variety of case studies, it is determined that only a distribution of the TCL characteristic frequency creates damping in the aggregate power dynamics. The beating effect decays over time due to damping, and a relationship between the beat's amplitude and period is presented.