Reverse-engineering of polynomial dynamical systems

Multivariate polynomial dynamical systems over finite fields have been studied in several contexts, including engineering and mathematical biology. An important problem is to construct models of such systems from a partial specification of dynamic properties, e.g., from a collection of state transition measurements. Here, we consider static models, which are directed graphs that represent the causal relationships between system variables, so-called wiring diagrams. This paper contains an algorithm which computes all possible minimal wiring diagrams for a given set of state transition measurements. The paper also contains several statistical measures for model selection. The algorithm uses primary decomposition of monomial ideals as the principal tool. An application to the reverse-engineering of a gene regulatory network is included. The algorithm and the statistical measures are implemented in Macaulay2 and are available from the authors

Parameter estimation for Boolean models of biological networks

Boolean networks have long been used as models of molecular networks and play an increasingly important role in systems biology. This paper describes a software package, Polynome, offered as a web service, that helps users construct Boolean network models based on experimental data and biological input. The key feature is a discrete analog of parameter estimation for continuous models. With only experimental data as input, the software can be used as a tool for reverse-engineering of Boolean network models from experimental time course data.Comment: Web interface of the software is available at http://polymath.vbi.vt.edu/polynome

Self-interest And Public Interest: The Motivations Of Political Actors

Self-Interest and Public Interest in Western Politics showed that the public, politicians, and bureaucrats are often public spirited. But this does not invalidate public-choice theory. Public-choice theory is an ideal type, not a claim that self-interest explains all political behavior. Instead, public-choice theory is useful in creating rules and institutions that guard against the worst case, which would be universal self-interestedness in politics. In contrast, the public-interest hypothesis is neither a comprehensive explanation of political behavior nor a sound basis for institutional design

Regulation and the Evolution of Corporate Boards: Monitoring, Advising or Window Dressing?

An earlier version of this paper was entitled “Deregulation and Board Composition: Evidence on the Value of the Revolving Door.”It is generally agreed that boards are endogenously determined institutions that serve both oversight and advisory roles in a firm. While the oversight role of boards has been extensively studied, relatively few studies have examined the advisory role of corporate boards. We examine the participation of political directors on the boards of natural gas companies between 1930 and 1998. We focus on the expansion of federal regulation of the natural gas industry in 1938 and 1954 and subsequent partial deregulation in 1986. Using data sets covering the periods from 1930 to 1990 and 1978 to 1998, we test whether regulation and deregulation altered the composition of companies' boards as the firms' environment changed. In particular, did regulation cause an increase and deregulation a decrease in the number of political directors on corporate boards? We find evidence that the number of political directors increases as firms shift from market to political competition. Specifically, the regulation of natural gas is associated with an increase in the number of political directors and deregulation is associated with a decrease in the number of political directors on boards

Visual masking and the dynamics of human perception, cognition, and consciousness A century of progress, a contemporary synthesis, and future directions

The 1990s, the “decade of the brain,” witnessed major advances in the study of visual perception, cognition, and consciousness. Impressive techniques in neurophysiology, neuroanatomy, neuropsychology, electrophysiology, psychophysics and brain-imaging were developed to address how the nervous system transforms and represents visual inputs. Many of these advances have dealt with the steady-state properties of processing. To complement this “steady-state approach,” more recent research emphasized the importance of dynamic aspects of visual processing. Visual masking has been a paradigm of choice for more than a century when it comes to the study of dynamic vision. A recent workshop (http://lpsy.epfl.ch/VMworkshop/), held in Delmenhorst, Germany, brought together an international group of researchers to present state-of-the-art research on dynamic visual processing with a focus on visual masking. This special issue presents peer-reviewed contributions by the workshop participants and provides a contemporary synthesis of how visual masking can inform the dynamics of human perception, cognition, and consciousness

Financing Direct Democracy: Revisiting the Research on Campaign Spending and Citizen Initiatives

The conventional view in the direct democracy literature is that spending against a measure is more effective than spending in favor of a measure, but the empirical results underlying this conclusion have been questioned by recent research. We argue that the conventional finding is driven by the endogenous nature of campaign spending: initiative proponents spend more when their ballot measure is likely to fail. We address this endogeneity by using an instrumental variables approach to analyze a comprehensive dataset of ballot propositions in California from 1976 to 2004. We find that both support and opposition spending on citizen initiatives have strong, statistically significant, and countervailing effects. We confirm this finding by looking at time series data from early polling on a subset of these measures. Both analyses show that spending in favor of citizen initiatives substantially increases their chances of passage, just as opposition spending decreases this likelihood

Institutional Transplant as Political Opportunity: The Practice and Politics of Indian Electricity Regulation

India has a decade-long experience with independent regulatory agencies in public services as an institutional transplant from the industrialized world. Introduced at the behest of international donor agencies, regulators in India are intended, somewhat naively, to provide an apolitical space for decision making to assuage investor concerns over arbitrary administrative actions, and thereby stimulate private investment. In practice, regulators have had to negotiate a terrain over which the state has continued to exercise considerable control. Regulators have also been been shaped in their functioning by national and sub-national political traditions and by administrative and political practices. The result is a hybrid institutional form that combines politics as usual with intriguing new, and unanticipated, opportunities for political intervention. This paper will explore the origins of electricity regulation as a form of institutional isomorphism. It will then compare the regulatory experience in India\u27s electricity sector across two Indian states to understand the implications of transplanting regulatory agencies in the global south. An examination of the process through which regulatory decisions are reached illustrates how existing bureaucratic and technocratic networks, transplanted procedures, and administrative cultures combine to conservatively manage long-standing political tensions around electricity. In seeking to manage those tensions, regulators often take decisions - on tariff setting, for example - based on a political reading that belies the technocratic narrative on which institutional credibility rests. At the same time, civil society groups ranging from residential associations to professional associations to individuals are using newly created regulatory spaces to structure a more deliberative decision process

Graduated Punishments in Public Good Games

I explain the ubiquitous use of graduated punishments by studying a repeated public good game in which a social planner imperfectly monitors agents to detect shirkers. Agents' cost of contributing is private information and administering punishments is costly. Using graduated punishments can be optimal for two reasons. It increases the price of future wrongdoing (temporal spillover effect) and it can lead to bad types revealing themselves (screening effect). The temporal spillover effect is always present if graduated punishments prevail, but screening need not occur if agents face a finite horizon. Whether or not a screening effect is exploited has a substantial impact on both outcomes and actual punishments. If the temporal spillover effect is sufficiently strong, then first-time shirkers are merely warned.</p