Novel method for rapid in vitro radiobioassay, A

2015 Spring.Includes bibliographical references.Rapid and accurate analysis of internal human exposure to radionuclides is essential to the effective triage and treatment of citizens who have possibly been exposed to radioactive materials in the environment. The two most likely scenarios in which a large number of citizens would be exposed are the detonation of a radiation dispersal device (RDD, "dirty bomb") or the accidental release of an isotope from an industrial source such as a radioisotopic thermal generator (RTG). In the event of the release and dispersion of radioactive materials into the environment in a large city, the entire population of the city - including all commuting workers and tourists - would have to be rapidly tested, both to satisfy the psychological needs of the citizens who were exposed to the mental trauma of a possible radiation dose, and to satisfy the immediate medical needs of those who received the highest doses and greatest levels of internal contamination - those who would best benefit from rapid, intensive medical care. In this research a prototype rapid screening method to screen urine samples for the presence of up to five isotopes, both individually and in a mixture, has been developed. The isotopes used to develop this method are Co-60, Sr-90, Cs-137, Pu-238, and Am-241. This method avoids time-intensive chemical separations via the preparation and counting of a single sample on multiple detectors, and analyzing the spectra for isotope-specific markers. A rapid liquid-liquid separation using an organic extractive scintillator can be used to help quantify the activity of the alpha-emitting isotopes. The method provides quantifiable results in less than five minutes for the activity of beta/gamma-emitting isotopes when present in the sample at the intervention level as defined by the Centers for Disease Control and Prevention (CDC), and quantifiable results for the activity levels of alpha-emitting isotopes present at their respective intervention levels in approximately 30 minutes of sample preparation and counting time. Radiation detector spectra - e.g. those from high-purity germanium (HPGe) gamma detectors and liquid scintillation detectors - which contain decay signals from multiple isotopes often have overlapping signals: the counts from one isotope's decay can appear in energy channels associated with another isotope's decay, complicating the calculation of each isotope's activity. The uncertainties associated with analyzing these spectra have been traced in order to determine the effects of one isotope's count rate on the sensitivity and uncertainty associated with each other isotope. The method that was developed takes advantage of activated carbon filtration to eliminate quenching effects and to make the liquid scintillation spectra from different urine samples comparable. The method uses pulse-shape analysis to reduce the interference from beta emitters in the liquid scintillation spectrum and improve the minimum detectable activity (MDA) and minimum quantifiable activity (MQA) for alpha emitters. The method uses an HPGe detector to quantify the activity of gamma emitters, and subtract their isotopes' contributions to the liquid scintillation spectra via a calibration factor, such that the pure beta and pure alpha emitters can be identified and quantified from the resulting liquid scintillation spectra. Finally, the method optionally uses extractive scintillators to rapidly separate the alpha emitters from the beta emitters when the activity from the beta emitters is too great to detect or quantify the activity from the alpha emitters without such a separation. The method is able to detect and quantify all five isotopes, with uncertainties and biases usually in the 10-40% range, depending upon the isotopic mixtures and the activity ratios between each of the isotopes

A multifrequency study of the Magellanic Clouds

This project examines the variety and nature of the radio sources in the Magellanic Clouds reprocessing recent and archival high sensitivity radio-continuum observations from the Australia Telescope Compact Array, using newly developed techniques and other large-scale surveys. This higher resolution and quality study creates a new complete catalogue of discrete and extended sources in the Magellanic Clouds, identifying background sources, Planetary Nebulae, and Supernova Remnants

How Nonpartisan Ballot Design Conceals Partisanship: A Survey Experiment of School Board

Studies suggest that between one-fourth and one-third of localities elect their leaders on partisan ballots. Does the presence of a party label on the ballot affect the level of partisanship in local office? I leverage the fact that within select states, school boards vary as to whether their members are elected on partisan or nonpartisan ballots. Do the differences in policy preferences between Democrats and Republicans differ across these ballot contexts? Does a party cue treatment, where respondents are reminded of the general policy positions of both parties, differentially affect elected officials in different ballot contexts? Evidence from the survey reveals a group of “polarized nonpartisans” who tend to express more partisan views about public policy than their co-partisans elected in an explicitly partisan system. At the same time, providing party cues in policy debates disproportionately moves those elected on partisan ballots as opposed to nonpartisan ones. That partisan-elected officials are more influenced by party cues appears to validate the motivations of nonpartisan reformers, yet the “polarized nonpartisans” found in the control group should give those reformers pause and reveals the need for continued research into the behavioral consequences of nonpartisan ballots

Improving Investigative Interviews: Facilitating Disclosure of Information through Implicit Means

Investigative interviews are essential to intelligence collection. However, eliciting information from subjects is challenging when they are not motivated to cooperate. Psychological research has examined social influence tactics that may influence an interviewee\u27s forthcomingness, however, there has been no focus on implicit methods despite their prominence in the basic social cognitive literature. Research on implicit cognition has found that activating mental concepts can lead people to behave in ways that are semantically related to or metaphorically consistent with the activated concept. In the present research, I sought to examine the concept of disclosure and test the effects of its activation on interviewees\u27 behavior. In a pilot study, I tested the effects of priming attachment security on the accessibility of disclosure-related concepts and found that disclosure entails concepts of communication, trust, and openness. Subsequently, I tested whether activating disclosure concepts by priming attachment security would influence people\u27s forthcomingness with information about a mock terrorism conspiracy. In a laboratory experiment, participants delivered a flash drive to a confederate who exposed them to details of a mock eco terrorism conspiracy, which they were subsequently interviewed about. Prior to being interviewed, half of the participants were primed; the other half were not. Results showed that primed participants disclosed more information than those who were not primed. Using the mock conspiracy and interviewing paradigm, I then tested the effects of activating disclosure concepts through an interview setting consistent with concepts of openness. Results converged: concepts of disclosure and openness overlap and can be contextually activated to promote information disclosure. The findings highlight the need for further research on basic nonconscious processes in investigative interviews, as such influences can affect the outcome of the interview. The operation of nonconscious influences in such contexts has implications for practitioners, who may be able to utilize priming to facilitate disclosure

Radio Planetary Nebulae in the Small Magellanic Cloud

We present ten new radio continuum (RC) detections at catalogued planetary nebula (PN) positions in the Small Magellanic Cloud (SMC): SMPS6, LIN 41, LIN 142, SMP S13, SMP S14, SMP S16, J18, SMP S18, SMP S19 and SMP S22. Additionally, six SMC radio PNe previously detected, LIN 45, SMP S11, SMPS17, LIN321, LIN339 and SMPS24 are also investigated (re-observed) here making up a population of 16 radio detections of catalogued PNe in the SMC. These 16 radio detections represent ~15 % of the total catalogued PN population in the SMC. We show that six of these objects have characteristics that suggest that they are PN mimics: LIN 41, LIN 45, SMP S11, LIN 142, LIN 321 and LIN 339. We also present our results for the surface brightness - PN radius relation ({\Sigma}-D) of the SMC radio PN population. These are consistent with previous SMC and LMC PN measurements of the ({\Sigma}-D) relation.Comment: Accepted for publication in Astrophysics and Space Scienc

Numerical Rule-Learning in Ring-Tailed Lemurs (Lemur Catta)

We investigated numerical discrimination and numerical rule-learning in ring-tailed lemurs (Lemur catta). Two ring-tailed lemurs were trained to respond to two visual arrays, each of which contained between one and four elements, in numerically ascending order. In Experiment 1, lemurs were trained with 36 exemplars of each of the numerosities 1–4 and then showed positive transfer to trial-unique novel exemplars of the values 1–4. In Experiments 2A and 2B, lemurs were tested on their ability to transfer an ascending numerical rule from the values 1–4 to novel values 5–9. Both lemurs successfully ordered the novel values with above chance accuracy. Accuracy was modulated by the ratio between the two numerical values suggesting that lemurs accessed the approximate number system when performing the task

Radio Planetary Nebulae in the Magellanic Clouds

We present preliminary results of our deep Australia Telescope Compact Array (ATCA) radio-continuum survey of the Magellanic Clouds Planetary Nebulae.Comment: 2 pages 1 figure, to appear in Planetary Nebulae an Eye to the Future Proceedings IAU Symposium No. 28

Radio-Continuum study of the Nearby Sculptor Group Galaxies. Part 1: NGC 300 at lambda = 20 cm

A series of new radio-continuum (lambda=20 cm) mosaic images focused on the NGC 300 galactic system were produced using archived observational data from the VLA and/or ATCA. These new images are both very sensitive (rms=60 microJy) and feature high angular resolution (<10"). The most prominent new feature is the galaxy's extended radio-continuum emission, which does not match its optical appearance. Using these newly created images a number of previously unidentified discrete sources have been discovered. Furthermore, we demonstrate that a joint deconvolution approach to imaging this complete data-set is inferior when compared to an immerge approach.Comment: 13 pages, 12 figures, accepted to APSS, new version to correct the missing reference

Phenotypic and Genomic Diversification in Complex Carbohydrate-Degrading Human Gut Bacteria

Symbiotic bacteria are responsible for the majority of complex carbohydrate digestion in the human colon. Since the identities and amounts of dietary polysaccharides directly impact the gut microbiota, determining which microorganisms consume specific nutrients is central for defining the relationship between diet and gut microbial ecology. Using a custom phenotyping array, we determined carbohydrate utilization profiles for 354 members of the Bacteroidetes, a dominant saccharolytic phylum. There was wide variation in the numbers and types of substrates degraded by individual bacteria, but phenotype-based clustering grouped members of the same species indicating that each species performs characteristic roles. The ability to utilize dietary polysaccharides and endogenous mucin glycans was negatively correlated, suggesting exclusion between these niches. By analyzing related Bacteroides ovatus/Bacteroides xylanisolvens strains that vary in their ability to utilize mucin glycans, we addressed whether gene clusters that confer this complex, multilocus trait are being gained or lost in individual strains. Pangenome reconstruction of these strains revealed a remarkably mosaic architecture in which genes involved in polysaccharide metabolism are highly variable and bioinformatics data provide evidence of interspecies gene transfer that might explain this genomic heterogeneity. Global transcriptomic analyses suggest that the ability to utilize mucin has been lost in some lineages of B. ovatus and B. xylanisolvens, which harbor residual gene clusters that are involved in mucin utilization by strains that still actively express this phenotype. Our data provide insight into the breadth and complexity of carbohydrate metabolism in the microbiome and the underlying genomic events that shape these behaviors