Bayesian Analysis of Continuous Time Models of the Australian Short Rate

This paper provides an empirical analysis of a range of alternative single-factor continuous time models for the Australian short-term interest rate. The models are indexed by the level effect parameter for the volatility in the short rate process. The inferential approach adopted is Bayesian, with estimation of the models proceeding via a Markov Chain Monte Carlo simulation scheme. Discrimination between the alternative models is based on Bayes factors, estimated from the simulation output using the Savage-Dickey density ratio. A data augmentation approach is used to improve the accuracy of the discrete time approximation of the continuous time models. An empirical investigation is conducted using weekly observations on the Australian 90 day interest rate from January 1990 to July 2000. The Bayes factors indicate that the square root diffusion model has the highest posterior probability of all the nested models.Interest Rate Models, Markov Chain Monte Carlo, Data Augmentation

Simulation-Based Bayesian Estimation of Affine Term Structure Models

This paper demonstrates the application of Bayesian simulation-based estimation to a class of interest rate models known as Affine Term Structure (ATS) models. The technique used is based on a Markov Chain Monte Carlo algorithm, with the discrete observations on yields augmented by additional higher frequency latent data. The introduction of augmented yield data reduces the bias associated with estimating a continuous time model using discretely observed data. The technique is demon-strated using a one-factor ATS model, with the latent factor process that underlies the yields sampled via a single-move algorithm. Numerical application of the method is demonstrated using both simulated and empirical data. Extension of the method to a three-factor ATS model is also discussed, as well as the application of a multi-move sampler based on a Kalman Filtering and Smoothing algorithm.Interest Rate Models, Markov Chain Monte Carlo, Data Augmentation, Nonlinear State Space Models, Kalman Filtering.

Mitochondrial DNA Mutations in Oxyphilic and Chief Cell Parathyroid Adenomas

Background: The potential pathogenetic significance of mitochondrial DNA (mtDNA) mutations in tumorigenesis is controversial. We hypothesized that benign tumorigenesis of a slowly replicating tissue like the human parathyroid might constitute an especially fertile ground on which a selective advantage conferred by mtDNA mutation could be manifested and might contribute to the oxyphilic phenotype observed in a subset of parathyroid tumors. Methods: We sought acquired mitochondrial DNA mutations by sequencing the entire 16.6 kb mitochondrial genome of each of thirty sporadic parathyroid adenomas (18 chief cell and 12 oxyphil cell), eight independent, polyclonal, parathyroid primary chief cell hyperplasias plus corresponding normal control samples, five normal parathyroid glands, and one normal thyroid gland. Results: Twenty-seven somatic mutations were identified in 15 of 30 (9 of 12 oxyphil adenomas, 6 of 18 chief cell) parathyroid adenomas studied. No somatic mutations were observed in the hyperplastic parathyroid glands. Conclusion: Features of the somatic mutations suggest that they may confer a selective advantage and contribute to the molecular pathogenesis of parathyroid adenomas. Importantly, the statistically significant differences in mutation prevalence in oxyphil vs. chief cell adenomas also suggest that mtDNA mutations may contribute to the oxyphil phenotype

Religiosity, Delinquency, and the Deterrent Effects of Informal Sanctions

Past research in deterrence theory suggests that informal social sanctions intervene in the effect of religiosity on criminal and delinquent behavior, such that more religious individuals tend to perceive stronger informal sanctions (Grasmick, Bursik and Cochran 1991a; Grasmick, Kinsey and Cochran 1991b). This study examines the influence of religiosity and social deterrence on college students\u27 delinquent behavior, as measured by anticipated violation of a university\u27s alcohol policy. Data were collected through a survey of undergraduate students (n = 484) at a large South-Midwestern public university that instituted a campus alcohol ban. The survey took place three months after the ban was implemented and asked students about religiosity, perceptions of informal deterrence, and expectations of violating the policy. Results partially support the hypothesis that religiosity predicts conformity primarily through the deterrent threat of informal sanctions. Religiosity increased perceived threats of shame and embarrassment, which in turn reduced the likelihood of anticipated policy violation. When controlling for demographics, college lifestyle, attitudes, and past drinking behavior, shame remained a significant predictor of expected policy violation, but embarrassment did not. Also, contrary to expectations, one measure of fundamentalist religiosity (biblical literalness) retained a direct main effect on intended compliance, even when taking informal sanctions into account. Theoretical, methodological, and policy implications are discussed

Automated synthesis of PET radiotracers by copperâ mediated 18Fâ fluorination of organoborons: Importance of the order of addition and competing protodeborylation

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142980/1/jlcr3583_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142980/2/jlcr3583.pd

HNRNPA1 promotes recognition of splice site decoys by U2AF2 in vivo

Alternative pre-mRNA splicing plays a major role in expanding the transcript output of human genes. This process is regulated, in part, by the interplay of trans-acting RNA binding proteins (RBPs) with myriad cis-regulatory elements scattered throughout pre-mRNAs. These molecular recognition events are critical for defining the protein-coding sequences (exons) within pre-mRNAs and directing spliceosome assembly on noncoding regions (introns). One of the earliest events in this process is recognition of the 3' splice site (3'ss) by U2 small nuclear RNA auxiliary factor 2 (U2AF2). Splicing regulators, such as the heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1), influence spliceosome assembly both in vitro and in vivo, but their mechanisms of action remain poorly described on a global scale. HNRNPA1 also promotes proofreading of 3'ss sequences though a direct interaction with the U2AF heterodimer. To determine how HNRNPA1 regulates U2AF-RNA interactions in vivo, we analyzed U2AF2 RNA binding specificity using individual-nucleotide resolution crosslinking immunoprecipitation (iCLIP) in control and HNRNPA1 overexpression cells. We observed changes in the distribution of U2AF2 crosslinking sites relative to the 3'ss of alternative cassette exons but not constitutive exons upon HNRNPA1 overexpression. A subset of these events shows a concomitant increase of U2AF2 crosslinking at distal intronic regions, suggesting a shift of U2AF2 to "decoy" binding sites. Of the many noncanonical U2AF2 binding sites, Alu-derived RNA sequences represented one of the most abundant classes of HNRNPA1-dependent decoys. We propose that one way HNRNPA1 regulates exon definition is to modulate the interaction of U2AF2 with decoy or bona fide 3'ss

Electron donor-dependent radionuclide reduction and nanoparticle formation by \u3ci\u3eAnaeromyxobacter dehalogenans\u3c/i\u3e strain 2CP-C

Anaeromyxobacter dehalogenans strain 2CP-C reduces U(VI) and Tc(VII) to U(IV)O2(s) (uraninite) and Tc(IV)O2(S) respectively. Kinetic studies with resting cells revealed that U(VI) or Tc(VII) reduction rates using H2 as electron donor exceeded those observed in acetate-amended incubations. The reduction of U(VI) by A. dehalogenans 2CP-C resulted in extracellular accumulation of ~5 nm uraninite nanoparticles in association with a lectin-binding extracellular polymeric substance (EPS). The electron donor did not affect UO2(S) nanoparticle size or association with EPS, but the utilization of acetate as the source of reducing equivalents resulted in distinct UO2(S) nanoparticle aggregates that were ~50 nm in diameter. In contrast, reduction of Tc(VII) by A. dehalogenans 2CP-C cell suspensions produced dense clusters of TcO2 particles, which were localized within the cell periplasm and on the outside of the outer membrane. In addition to direct reduction, A. dehalogenans 2CP-C cell suspensions reduced Tc(VII) indirectly via an Fe(II)-mediated mechanism. Fe(II) produced by strain 2CP-C from either ferrihydrite or Hanford Site sediment rapidly removed 99Tc(VII)O4– from solution

Electron donor-dependent radionuclide reduction and nanoparticle formation by \u3ci\u3eAnaeromyxobacter dehalogenans\u3c/i\u3e strain 2CP-C

Anaeromyxobacter dehalogenans strain 2CP-C reduces U(VI) and Tc(VII) to U(IV)O2(s) (uraninite) and Tc(IV)O2(S) respectively. Kinetic studies with resting cells revealed that U(VI) or Tc(VII) reduction rates using H2 as electron donor exceeded those observed in acetate-amended incubations. The reduction of U(VI) by A. dehalogenans 2CP-C resulted in extracellular accumulation of ~5 nm uraninite nanoparticles in association with a lectin-binding extracellular polymeric substance (EPS). The electron donor did not affect UO2(S) nanoparticle size or association with EPS, but the utilization of acetate as the source of reducing equivalents resulted in distinct UO2(S) nanoparticle aggregates that were ~50 nm in diameter. In contrast, reduction of Tc(VII) by A. dehalogenans 2CP-C cell suspensions produced dense clusters of TcO2 particles, which were localized within the cell periplasm and on the outside of the outer membrane. In addition to direct reduction, A. dehalogenans 2CP-C cell suspensions reduced Tc(VII) indirectly via an Fe(II)-mediated mechanism. Fe(II) produced by strain 2CP-C from either ferrihydrite or Hanford Site sediment rapidly removed 99Tc(VII)O4– from solution

Stereoselective synthesis of hydroxylated 3-aminoazepanes using a multi-bond forming, three-step tandem process

A multi-bond forming, three-step tandem process involving a palladium(II)-catalysed Overman rearrangement and a ring closing metathesis reaction has been utilised for the efficient synthesis of a 2,3,6,7-tetrahydro-3-amidoazepine. Substrate directed epoxidation or dihydroxylation of this synthetic intermediate has allowed the diastereoselective synthesis of hydroxylated 3-aminoazepanes including the syn-diastereomer of the balanol core. Asymmetric synthesis of the 2,3,6,7-tetrahydro-3-amidoazepine motif was also achieved using a chiral palladium(II)-catalyst during the Overman rearrangement