Why Hedges’ g*s based on the non-pooled standard deviation should be reported with Welch’s t-test

Researchers are generally required to report and interpret effect sizes and associated confidence intervals. When comparing two independent groups, the most commonly used estimator of effect size is Cohen’s ds where sample mean difference is divided by the pooled standard deviation. However, computing the pooled error term is not valid when both groups do not share common population variances. Furthermore, the assumption of equal population variances is unlikely in many psychological fields. Consequently, researchers shift to the use of Welch’s t-test over Student’s t-test in the context of hypothesis testing. Meanwhile, the question which effect size to report when equal variances are not assumed remains open. Based on Monte Carlo simulations, we compare Hedges’ gs (i.e. Cohen’s ds with correction for bias) to Glass’s gs, Shieh’s gs and Hedges’ g_s^*. Comparisons are made under normality as well as under realistic deviations from the assumptions of normality and equal variances. Although it is not directly related with Welch’s t-test (unlike Shieh’s gs), we recommend the use of Hedges’ g_s^* because it shows better properties than all other estimators. Practical recommendations, R package and Shiny App in order to compute effect size estimators and confidence intervals are provided.

Evolution of fold switching in a metamorphic protein

Metamorphic proteins switch between different folds, defying the protein folding paradigm. It is unclear how fold switching arises during evolution. With ancestral reconstruction and nuclear magnetic resonance, we studied the evolution of the metamorphic human protein XCL1, which has two distinct folds with different functions, making it an unusual member of the chemokine family, whose members generally adopt one conserved fold. XCL1 evolved from an ancestor with the chemokine fold. Evolution of a dimer interface, changes in structural constraints and molecular strain, and alteration of intramolecular protein contacts drove the evolution of metamorphosis. Then, XCL1 likely evolved to preferentially populate the noncanonical fold before reaching its modern-day near-equal population of folds. These discoveries illuminate how one sequence has evolved to encode multiple structures, revealing principles for protein design and engineering.

Lattice Studies of Gerrymandering Strategies

A new theoretical method for examining gerrymandering is presented based on lattice models of voters, in which districts are constructed by partitioning the lattice. We propose three novel algorithms for constructing equal-population, connected districts which favor the gerrymanderer and incorporate the spatial distribution of voters. Due to the probabilistic population fluctuations inherent to our voter models, Monte Carlo techniques can be applied to study the impact of gerrymandering. We use the method developed here to compare our different gerrymandering algorithms, show approaches which ignore spatial data lead to (legally prohibited) disconnected districts, and examine the effectiveness of isoperimetric quotient tests.

Between Stars and Stripes: Regions for American Healthcare Reform

Analyzes government administration healthcare reform requires. Defines vast scaling of enterprise to cover the entire US. Reviews management constraints to supervise and learn. Always requires hierarchies. Too many layers pass effectiveness thresholds. Proposed reforms: "Medicare for All," may extend UK NHS-like program to US residents; "Public Option" may extend government insurance to US residents who choose it. Debate thus far about costs. Administrative requirements more critical to success (or failure.) Ignored in some plans. Examine how scale is managed in healthcare delivery, in smaller and some large nations. Administration of major medical reforms across US market will take a decade plus to roll-out. Must be carefully managed, to meet healthcare expectations and maintain political support. Success will exploit regionalisation, seeding new programs in areas with equal population sizes and ethnic compositions. Nationalization of some insurers is better than "putting them out of business," could smooth Public Option surge. But perfection is enemy of good: success will follow Moynihan's rule: show benefits to the privileged to serve the underprivileged.

Multiobjective Genetic Algorithms for Reinforcing Equal Population in Congressional Districts

Redistricting is the process of partitioning a set of basic units into a given number of larger groups for electoral purposes. These groups must follow federal and state requirements to enhance fairness and minimize the impact of manipulating boundaries for political gain. In redistricting tasks, one of the most important criteria is equal population. As a matter of fact, redistricting plans can be rejected when the population deviation exceeds predefined limits. In the literature, there are several methods to balance population among districts. However, further discussion is needed to assess the effectiveness of these strategies. In this paper, we considered two different strategies, mean deviation and overall range. Additionally, a compactness measure is included to design well-shaped districts. In order to provide a wide set of redistricting plans that achieve good trade-offs between mean deviation, overall range, and compactness, we propose four multiobjective metaheuristic algorithms based on NSGA-II and SPEA-II. The proposed strategies were applied in California, Texas, and New York. Numerical results show that the proposed multiobjective approach can be a very valuable tool in any real redistricting process.

Why We Should be Negative about Positive Egalitarianism

The article assesses recent attempts to deflect two persistent objections to Positive Egalitarianism (PE), the view that equality adds to the goodness of a state of affairs. The first says that PE entails bringing into existence individuals who are equal to each other in leading horrible lives, such that they are worth not living. I assess three strategies for deflecting this objection: offering a restricted version of PE; biting the bullet; and pressing a levelling out counter-objection. The second objection points out that for any world A containing many individuals all leading very satisfying lives, and in perfect equality, PE prefers a much larger, perfectly equal population Z with much lower (yet positive) well-being. I review two main strategies for avoiding this Repellent Conclusion: a Capped Model and making egalitarianism sensitive to welfare levels. Both solutions, I show, are worse than the problems they are meant to solve.

Mapping the topology of the air transport network in Turkey

Recent technological and philosophical research has revealed that almost everything around us is heavily dependent on network-based complexities. Airport network topologies are complex networks and their analyses are crucial regarding the fact that the evolution of airport network topology influences the economic growth of regions and countries. An equal population cartogram is derived displaying the distortion of the air transport network of Turkey in accordance with the uneven distribution of passengers. The regions between İstanbul, Ankara, İzmir, and Antalya are shrunk by the force of higher population concentration. The shrinkage across the eastern regions is less than that in the western regions; still, the distortion of the regions is dominated by particular regional hubs.

Visualizing the road network topology differences of Istanbul city

This study aims at visualizing the spatial distribution of road network per person in the city of Istanbul, Turkey. As a world city, Istanbul connects two continents and has almost 15 million population. Therefore, the city has a tremendous road network consists of 713,634 edges and 242,545 nodes. The road network is mapped on an equal population distribution cartogram for displaying where the least and the most amount of roads per person exist. These feature graphs might help planners, geographers, decision makers etc. for improving their understandings regarding the network topology of the road network.