If politicians in the United States were paid better, would more middle- and working-class people become politicians? Reformers often argue that the low salaries paid in state and local governments ...make holding office economically infeasible for lower-income citizens and contribute to the enduring numerical under-representation of the working class in our political institutions. Of course, raising politicians’ salaries could also make political office more attractive to affluent professionals, increasing competition for office and ultimately discouraging lower-income citizens from running and winning. In this article, we test these hypotheses using data on the salaries and economic backgrounds of state legislators. Contrary to the notion that paying politicians more promotes economic diversity, we find that the descriptive representation of the working class is the same or worse in states that pay legislators higher salaries. These findings have important implications for research on descriptive representation, political compensation, and political inequality.
We show how to integrate a variable elimination approach to solving influence diagrams with a value iteration approach to solving finite-horizon partially observable Markov decision processes ...(POMDPs). The integration of these approaches creates a variable elimination algorithm for influence diagrams that has much more relaxed constraints on elimination order, which allows improved scalability in many cases. The new algorithm can also be viewed as a generalization of the value iteration algorithm for POMDPs that solves non-Markovian as well as Markovian problems, in addition to leveraging a factored representation for improved efficiency. The development of a single algorithm that integrates and generalizes both of these classic algorithms, one for influence diagrams and the other for POMDPs, unifies these two approaches to solving Bayesian decision problems in a way that combines their complementary advantages.
Medical imaging is routine in the diagnosis and staging of a wide range of medical conditions. In particular, magnetic resonance imaging (MRI) is critical for visualizing soft tissue and organs, with ...over 60 million MRI procedures performed each year worldwide. About one-third of these procedures are contrast-enhanced MRI, and gadolinium-based contrast agents (GBCAs) are the mainstream MRI contrast agents used in the clinic. GBCAs have shown efficacy and are safe to use with most patients; however, some GBCAs have a small risk of adverse effects, including nephrogenic systemic fibrosis (NSF), the untreatable condition recently linked to gadolinium (Gd) exposure during MRI with contrast. In addition, Gd deposition in the human brain has been reported following contrast, and this is now under investigation by the US Food and Drug Administration (FDA). To address a perceived need for a Gd-free contrast agent with pharmacokinetic and imaging properties comparable to GBCAs, we have designed and developed zwitterion-coated exceedingly small superparamagnetic iron oxide nanoparticles (ZES-SPIONs) consisting of ∼3-nm inorganic cores and ∼1-nm ultrathin hydrophilic shell. These ZES-SPIONs are free of Gd and show a high T₁ contrast power. We demonstrate the potential of ZES-SPIONs in preclinical MRI and magnetic resonance angiography.
Why do some members of Congress vote more on the extremes of their party than others? I argue that lawmakers representing more homogeneously white districts have greater electoral incentive to ...moderate their voting records, since the two parties compete more for support of white voters than for the support of minority voters. I provide evidence using roll-call votes from the U.S. House and Senate. I find members representing more homogeneously white districts have more moderate voting records, a finding that holds for Democrats and Republicans. I explore two potential mechanisms: legislator responsiveness and electoral punishment. While legislators do not seem to adjust their voting behavior in response to short-term changes in district racial composition, more homogeneously white districts are found to assess larger vote share penalties on more extreme candidates in general elections. The findings have implications for our understanding of race, representation, and electoral accountability.
Despite their importance, the synthesis of alkylated heterocycles from the cross-coupling of Lewis basic nitrogen heteroaryl halides with alkyl halides remains a challenge. We report here a general ...solution to this challenge enabled by a new collection of ligands based around 2-pyridyl-N-cyanocarboxamidine and 2-pyridylcarboxamidine cores. Both primary and secondary alkyl halides can be coupled with 2-, 3-, and 4-pyridyl halides as well as other more complex heterocycles in generally good yields (41 examples, 69% ave yield).
Strategy Graphs for Influence Diagrams Hansen, Eric A.; Shi, Jinchuan; Kastrantas, James
The Journal of artificial intelligence research,
01/2022, Volume:
75
Journal Article
Peer reviewed
Open access
An influence diagram is a graphical model of a Bayesian decision problem that is solved by finding a strategy that maximizes expected utility. When an influence diagram is solved by variable ...elimination or a related dynamic programming algorithm, it is traditional to represent a strategy as a sequence of policies, one for each decision variable, where a policy maps the relevant history for a decision to an action. We propose an alternative representation of a strategy as a graph, called a strategy graph, and show how to modify a variable elimination algorithm so that it constructs a strategy graph. We consider both a classic variable elimination algorithm for influence diagrams and a recent extension of this algorithm that has more relaxed constraints on elimination order that allow improved performance. We consider the advantages of representing a strategy as a graph and, in particular, how to simplify a strategy graph so that it is easier to interpret and analyze.
While reductive cross-electrochemical coupling is an attractive approach for the synthesis of complex molecules at both small and large scale, two barriers for large-scale applications have remained: ...the use of stoichiometric metal reductants and a need for amide solvents. In this communication, new conditions that address these challenges are reported. The nickel-catalyzed reductive cross-coupling of aryl bromides with alkyl bromides can be conducted in a divided electrochemical cell using acetonitrile as the solvent and diisopropylamine as the sacrificial reductant to afford coupling products in synthetically useful yields (22–80%). Additionally, the use of a combination of the ligands 4,4′,4″-tri-tert-butyl-2,2′:6′,2′-terpyridine and 4,4′-di-tert-butyl-2,2′-bipyridine is essential to achieve high yields.
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