Douglas VanDerwerken

GC/MS method for positive detection of Bacillus anthracis endospores.

A simple method was developed for detection of Bacillus anthracis (BA) endospores and for differentiation of them from other species in the Bacillus cereus group. Chemical profiles that include lipids (i.e., fatty acids), carbohydrates (i.e., sugars), and the spore-specific biomarker, dipicolinic acid, were generated by one-step thermochemolysis (TCM) at 140 °C in 5 min to provide specific biomarker signatures. Anthrose, which is a biomarker characteristic of the B. cereus group of bacteria, was determined from a fragment produced by TCM. Surprisingly, several virulent BA strains contained very low levels of anthrose, which confounded their detection. A statistical discrimination algorithm was constructed using a combination of biomarkers, which was robust against different growth conditions (medium and temperature). Fifteen endospore-forming Bacillus species were confirmed in a statistically designed test (~90%) using the algorithm, including six BA strains (four virulent isolates), five B. thuringiensis (BT) isolates, and one isolate each for B. cereus (BC), B. mycoides (BM), B. atrophaeus (BG), and B. subtilis (BS). The detection limit for B. anthracis was found to be 50,000 endospores, on the basis of the GC/MS detection limits for 3-methyl-2-butenoic acid methyl ester, which is the biomarker derived from TCM of anthrose.

Does the Threat of Suspension Curb Dangerous Behavior in Soccer? A Case Study From the Premier League

Using data from the 2011-2012 season of the Premier League, we study empirically and theoretically the impact of soccer suspension rules on the behavior of players and referees. For players facing a potential one-game suspension, being one versus two yellow cards away from the suspension limit results in an approximate 12% reduction in fouling, while for those facing a potential two-game suspension, the reduction is approximately 23%. The probability such players receive a yellow card is also reduced. In addition, we find some evidence of slight referee bias for the home team in the dispensing of penalty cards, but not in the calling of fouls. Finally, we develop a theoretical framework for investigating the effects of suspension rules on the number of fouls committed. Within this framework, we investigate how policy instruments such as referees’ propensity to give out yellow cards or their consistency in giving them out affect the impact of suspension rules.

In vivo luminescent imaging of NF-κB activity and NF-κB-related serum cytokine levels predict pain sensitivities in a rodent model of peripheral neuropathy

Methods for the detection of the temporal and spatial generation of painful symptoms are needed to improve the diagnosis and treatment of painful neuropathies and to aid preclinical screening of molecular therapeutics.

Taking a closer look at Latino parents at one Spanish–English two-way immersion charter school

Scholars who work with Latino/as in the USA have long been calling for a more nuanced understanding of the heterogeneity of the US-based Latino population. Two-way Immersion (TWI) bilingual education programmes are an interesting context in which to examine the Latino parent communities in the USA. Overall, the language enrichment nature of TWI programmes attracts diverse parents from across many different demographic groups, and for a variety of reasons. This study uses an innovative application of cluster analysis to examine the parent population at one TWI Spanish–English elementary school. Survey questions asked were: parents’ income, educational achievement, ethnicity, language spoken at home, religious affiliation, country of origin and residential distance from the school. Our analyses reveal that parents in our sample can be classified into four distinct groups based on the combinations of included characteristics. Our analyses show the emergence of three Latino parent clusters and one Caucasian parent cluster. These analyses show how accounting for the different social dimensions of these parents’ lives simultaneously can provide a more nuanced understanding of the Latino parents at this school.

A generative Markov model for bowling scores

Abstract We create a data-driven Markov model for generating 10-pin bowling scores from the Professional Bowlers Association. The model incorporates insights from the hot hand literature and makes use of Bayesian shrinkage. For realistic sample sizes, the proposed approach is superior to modeling via the empirical distribution. Investigation of player-specific model components allows for a richer comparison of players than is possible using raw game scores alone. An additional feature of the model is that it can be used for in-game prediction.

Monitoring Joint Convergence of MCMC Samplers

ABSTRACT We present a diagnostic for monitoring convergence of a Markov chain Monte Carlo (MCMC) sampler to its target distribution. In contrast to popular existing methods, we monitor convergence to the joint target distribution directly rather than a select scalar projection. The method uses a simple nonparametric posterior approximation based on a state-space partition obtained by clustering the pooled draws from multiple chains, and convergence is determined when the estimated posterior probabilities of partition elements under each chain are sufficiently similar. This framework applies to a wide variety of problems, and generalizes directly to non-Euclidean state spaces. Our method also provides approximate high-posterior-density regions, and a characterization of differences between nonconverged chains, all with little additional computational burden. We demonstrate this approach on applications to sampling posterior distributions over , graphs, and partitions. Supplementary materials for this article are available online.

Not every Gibbs sampler is a special case of the Metropolis–Hastings algorithm

ABSTRACT It is commonly asserted that the Gibbs sampler is a special case of the Metropolis–Hastings (MH) algorithm. While this statement is true for certain Gibbs samplers, it is not true in general for the version that is taught and used most often, namely, the deterministic scan Gibbs sampler. In this note, I prove that that there exist deterministic scan Gibbs samplers that do not exhibit detailed balance and hence cannot be considered MH samplers. The nuances of various Gibbs sampling schemes are discussed.

Bayesian Assessment of Genetic Risk in Families with a Balanced Translocation

An important problem from the field of genetics involves the calculation of a personalized risk estimate on behalf of a heterozygous carrier of a balanced translocation. Though phenotypically normal, the carrier may be at increased risk of having a child who is mentally and physically abnormal due to an unbalanced translocation of chromosomal segments. An accurate estimate of the probability of this event is understandably desirable. Unfortunately, translocations are almost always family-specific so there is very little data that are perfectly relevant and one has to rely heavily on general risk figures derived from studies of families with similar translocations. This makes the problem particularly well suited to Bayesian analysis, which coherently combines family-specific data and a priori knowledge. However, much of the genetics counseling literature recommends an either/or approach: if the family is large enough, use family data; else, use pooled population data. In this article, we describe how uncertainty can be significantly reduced by incorporating all available information in the context of deriving a risk estimate for a hypothetical familial translocation.