An Economist’s Guide to Heaven

This paper is the first to offer an economic model of God and humanity as optimizing agents in the context of concrete belief archetypes (religious ‘contracts’) in Judeo-Christian theology. Data support the model’s unique predictions, despite their otherwise counterintuitive, unlikely nature. For example, the model requires that in one belief archetype, ‘good works’ not increase with strength of faith, as one might otherwise expect, and that what appears may be God’s dominant contract precisely balances divine penalties for reneging on promises with incentives to seek divine ‘gifts’—an equivalence supported in the data.economics;religion

Exact reconstruction of gene regulatory networks using compressive sensing.

BackgroundWe consider the problem of reconstructing a gene regulatory network structure from limited time series gene expression data, without any a priori knowledge of connectivity. We assume that the network is sparse, meaning the connectivity among genes is much less than full connectivity. We develop a method for network reconstruction based on compressive sensing, which takes advantage of the network's sparseness.ResultsFor the case in which all genes are accessible for measurement, and there is no measurement noise, we show that our method can be used to exactly reconstruct the network. For the more general problem, in which hidden genes exist and all measurements are contaminated by noise, we show that our method leads to reliable reconstruction. In both cases, coherence of the model is used to assess the ability to reconstruct the network and to design new experiments. We demonstrate that it is possible to use the coherence distribution to guide biological experiment design effectively. By collecting a more informative dataset, the proposed method helps reduce the cost of experiments. For each problem, a set of numerical examples is presented.ConclusionsThe method provides a guarantee on how well the inferred graph structure represents the underlying system, reveals deficiencies in the data and model, and suggests experimental directions to remedy the deficiencies

The rising share of nonmarital births: A response to Ermisch, Martin, and Wu

We are flattered that our recent paper in Demography, GSS (2006), has attracted such close attention from Ermisch Martin and Wu (EMW). In this response we appreciate the opportunity to expand on several key aspects of our paper, but see no reason to substantially revise any of our major conclusions based on EMW comments. Reading EMW, one might think we had proposed the demographic equivalent of Newton’s second law of thermodynamics – the existence of a universal phenomenon, manifest in identical form in all places, for all groups, during all times periods, regardless of circumstances. It will be helpful, then, to review briefly the central points in GSS before turning to the major EMW comments, along with our responses.fertility, illegitimacy ratio, marriage, nonmarital fertility ratio, nonmarital births

Ricardian equivalence for sub-national states

The authors test Ricardian equivalence within an endogenous growth model for U.S. states, which have high rates of migration relative to most countries. Results are consistent with both Ricardian equivalence and endogenous growth, despite the relative ease of migration. Increases in productive government expenditures increase long-run real growth by the same amount, for example, whether financed by taxes or bonds. State rules limiting the use of bond financing may play a role in supporting Ricardian equivalence. The study provides the first explicit test of Ricardian equivalence for sub-national states in the context of an endogenous growth model.endogenous growth

Joint estimation of multiple related biological networks

Graphical models are widely used to make inferences concerning interplay in multivariate systems. In many applications, data are collected from multiple related but nonidentical units whose underlying networks may differ but are likely to share features. Here we present a hierarchical Bayesian formulation for joint estimation of multiple networks in this nonidentically distributed setting. The approach is general: given a suitable class of graphical models, it uses an exchangeability assumption on networks to provide a corresponding joint formulation. Motivated by emerging experimental designs in molecular biology, we focus on time-course data with interventions, using dynamic Bayesian networks as the graphical models. We introduce a computationally efficient, deterministic algorithm for exact joint inference in this setting. We provide an upper bound on the gains that joint estimation offers relative to separate estimation for each network and empirical results that support and extend the theory, including an extensive simulation study and an application to proteomic data from human cancer cell lines. Finally, we describe approximations that are still more computationally efficient than the exact algorithm and that also demonstrate good empirical performance.Comment: Published in at http://dx.doi.org/10.1214/14-AOAS761 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

A simulation-based design paradigm for complex cast components

This paper describes and exercises a new design paradigm for cast components. The methodology integrates foundry process simulation, non-destructive evaluation (NDE), stress analysis and damage tolerance simulations into the design process. Foundry process simulation is used to predict an array of porosity-related anomalies. The probability of detection of these anomalies is investigated with a radiographic inspection simulation tool (XRSIM). The likelihood that the predicted array of anomalies will lead to a failure is determined by a fatigue crack growth simulation based on the extended finite element method and therefore does not require meshing nor remeshing as the cracks grow. With this approach, the casting modeling provides initial anomaly information, the stress analysis provides a value for the critical size of an anomaly and the NDE assessment provides a detectability measure. The combination of these tools allows for accept/reject criteria to be determined at the early design stage and enables damage tolerant design philosophies. The methodology is applied to the design of a cast monolithic door used on the Boeing 757 aircraf

Genomic aberrations in normal tissue adjacent to HER2-amplified breast cancers: field cancerization or contaminating tumor cells?

Field cancerization effects as well as isolated tumor cell foci extending well beyond the invasive tumor margin have been described previously to account for local recurrence rates following breast conserving surgery despite adequate surgical margins and breast radiotherapy. To look for evidence of possible tumor cell contamination or field cancerization by genetic effects, a pilot study (Study 1: 12 sample pairs) followed by a verification study (Study 2: 20 sample pairs) were performed on DNA extracted from HER2-positive breast tumors and matching normal adjacent mammary tissue samples excised 1-3 cm beyond the invasive tumor margin. High-resolution molecular inversion probe (MIP) arrays were used to compare genomic copy number variations, including increased HER2 gene copies, between the paired samples; as well, a detailed histologic and immunohistochemical (IHC) re-evaluation of all Study 2 samples was performed blinded to the genomic results to characterize the adjacent normal tissue composition bracketing the DNA-extracted samples. Overall, 14/32 (44 %) sample pairs from both studies produced genome-wide evidence of genetic aberrations including HER2 copy number gains within the adjacent normal tissue samples. The observed single-parental origin of monoallelic HER2 amplicon haplotypes shared by informative tumor-normal pairs, as well as commonly gained loci elsewhere on 17q, suggested the presence of contaminating tumor cells in the genomically aberrant normal samples. Histologic and IHC analyses identified occult 25-200 μm tumor cell clusters overexpressing HER2 scattered in more than half, but not all, of the genomically aberrant normal samples re-evaluated, but in none of the genomically normal samples. These genomic and microscopic findings support the conclusion that tumor cell contamination rather than genetic field cancerization represents the likeliest cause of local clinical recurrence rates following breast conserving surgery, and mandate caution in assuming the genomic normalcy of histologically benign appearing peritumor breast tissue

Integrating biological knowledge into variable selection : an empirical Bayes approach with an application in cancer biology

Background: An important question in the analysis of biochemical data is that of identifying subsets of molecular variables that may jointly influence a biological response. Statistical variable selection methods have been widely used for this purpose. In many settings, it may be important to incorporate ancillary biological information concerning the variables of interest. Pathway and network maps are one example of a source of such information. However, although ancillary information is increasingly available, it is not always clear how it should be used nor how it should be weighted in relation to primary data. Results: We put forward an approach in which biological knowledge is incorporated using informative prior distributions over variable subsets, with prior information selected and weighted in an automated, objective manner using an empirical Bayes formulation. We employ continuous, linear models with interaction terms and exploit biochemically-motivated sparsity constraints to permit exact inference. We show an example of priors for pathway- and network-based information and illustrate our proposed method on both synthetic response data and by an application to cancer drug response data. Comparisons are also made to alternative Bayesian and frequentist penalised-likelihood methods for incorporating network-based information. Conclusions: The empirical Bayes method proposed here can aid prior elicitation for Bayesian variable selection studies and help to guard against mis-specification of priors. Empirical Bayes, together with the proposed pathway-based priors, results in an approach with a competitive variable selection performance. In addition, the overall procedure is fast, deterministic, and has very few user-set parameters, yet is capable of capturing interplay between molecular players. The approach presented is general and readily applicable in any setting with multiple sources of biological prior knowledge

Serum dioxin levels in former New Zealand sawmill workers twenty years after exposure to pentachlorophenol (PCP) ceased.

From the 1950s to the late 1980s pentachlorophenol (PCP) based anti-sapstain fungicides were widely used in the New Zealand timber industry. Workers involved in treatment, or those handling freshly treated timber, experienced significant PCP exposure. Commercial grade PCP contained contaminants including 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners. To determine whether PCP exposure had resulted in elevated serum dioxin levels twenty years after its use had ceased we tested 94 former sawmill workers randomly selected from surviving members of a cohort enumerated for a mortality and cancer incidence study. After interviewing these individuals to collect demographic data and a comprehensive work history, they were divided into 71 PCP-exposed and 23 non-exposed individuals on the basis of job title and work tasks performed. We compared age-adjusted dioxin levels in the exposed and non-exposed groups, examined the effect of PCP exposure duration and intensity, and compared congener profiles with those found in the commercial grade PCP used at the time. Mean levels in exposed workers were elevated when compared with the non-exposed, with levels of 1,2,3,6,7,8-HxCDD, 1,2,3,4,6,7,8-HpCDD and OCDD being two to three times higher. The congener profiles in serum were consistent with those in PCP solutions, and dioxin levels increased with both employment duration and estimated exposure intensity. Serum dioxin levels in former New Zealand sawmill workers remain elevated twenty years after exposure to PCP ceased, and reflect the pattern of past PCP exposure

Granting political representation to non-humans

This commentary discusses the representation of individuals versus populations — human and nonhuman, present and future — in Treves et al.’s proposed trusteeship for futurity. Terminological questions are also discussed