Mitigation of 42^{42}Ar/42^{42}K background for the GERDA Phase II experiment

Background coming from the $^{42}$Ar decay chain is considered to be one of the most relevant for the GERDA experiment, which aims to search of the neutrinoless double beta decay of $^{76}$Ge. The sensitivity strongly relies on the absence of background around the Q-value of the decay. Background coming from $^{42}$K, a progeny of $^{42}$Ar, can contribute to that background via electrons from the continuous spectrum with an endpoint of 3.5 MeV. Research and development on the suppression methods targeting this source of background were performed at the low-background test facility LArGe. It was demonstrated that by reducing $^{42}$K ion collection on the surfaces of the broad energy germanium detectors in combination with pulse shape discrimination techniques and an argon scintillation veto, it is possible to suppress the $^{42}$K background by three orders of magnitude. This is sufficient for Phase II of the GERDA experiment

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Highly sensitive gamma-spectrometers of GERDA for material screening: Part I

The GERDA experiment aims to search for the neutrinoless double beta-decay of 76Ge and possibly for other rare processes. The sensitivity of the first phase is envisioned to be more than one order of magnitude better than in previous neutrinoless double beta-decay experiments. This implies that materials with ultra-low radioactive contamination need to be used for the construction of the detector and its shielding. Therefore the requirements on material screening include high-sensitivity low-background detection techniques and long measurement times. In this article, an overview of material-screening laboratories available to the GERDA collaboration is given, with emphasis on the gamma-spectrometry. Additionally, results of an intercomparison of the evaluation accuracy in these laboratories are presented.Comment: Featured in: Proceedings of the XIV International Baksan School "Particles and Cosmology" Baksan Valley, Kabardino-Balkaria, Russia, April 16-21,2007. INR RAS, Moscow 2008. ISBN 978-5-94274-055-9, pp. 228-232; (5 pages, 0 figures

SPARKLE (Subtypes of ischaemic stroke classification system), Incorporating measurement of carotid plaque burden: A new validated tool for the classification of ischemic stroke subtypes

Background: Previous classification systems of acute ischemic stroke (Causative Classification System, CCS, of acute ischemic stroke, Trial of Org 10172 in Acute Stroke Treatment, TOAST) established the diagnosis of large artery disease (LAD) based on the presence or absence of carotid stenosis. However, carotid plaque burden is a stronger predictor of cardiovascular risk than stenosis. Our objective was to update definitions of ischemic stroke subtypes to improve the detection of LAD and to assess the validity and reliability of a new classification system: SPARKLE (Subtypes of Ischaemic Stroke Classification System). Methods: In a retrospective review of clinical research data, we compared three stroke subtype classifications: CCS, TOAST and SPARKLE. We analyzed a random sample of 275 patients presenting with minor stroke or transient ischemic attack (TIA) in an Urgent TIA Clinic in London, Ont., Canada, between 2002 and 2012. Results: There was substantial overall agreement between SPARKLE and CCS (κ = 0.75), with significant differences in the rate of detection of LAD, cardioembolic and undetermined causes of stroke or TIA. The inter-rater reliability of SPARKLE was substantial (κ = 0.76) and the intra-rater reliability was excellent (κ = 0.91). Conclusion: SPARKLE is a valid and reliable classification system, providing advantages compared to CCS and TOAST. The incorporation of plaque burden into the classification of LAD increases the proportion of cases attributable to LAD and reduces the proportion classified as being of \u27undetermined\u27 etiology. © 2014 S. Karger AG, Basel

An Empirical Test of a Communibiological Model of Trait Verbal Aggressiveness

The purpose of this study was to test Beatty and McCroskey\u27s communibiological model of trait verbal aggressiveness. In general, this model views trait verbal aggressiveness as an expression of temperament; specifically, that trait verbal aggressiveness represents low thresholds for the fight or flight (FFS) neurobiological system. This model further contends that behavioral inhibition circuitry (BIS) moderates FFS activation by tempering aggressive impulses, otherwise FFS activation would manifest itself in the form of physical rather than verbal attacks. Beatty and McCroskey (1997) propose that low thresholds for stimulating the behavioral activation system (BAS) should be related to trait verbal aggressiveness to the extent that the construct involves a proactive rather than a purely reactive interpersonal function. Because previous research indicated that psychoticism (P), neuroticism (N) and extroversion (E) represent psychological manifestations of the FFS, BIS, and BAS systems, respectively, hypotheses linking P, N, and E to trait verbal aggressiveness (VAS) were tested. A multiple regression equation based on disattenuated correlations explained approximately 46% of the variance in VAS scores. Specifically, (1) the results for P and N were consistent with predictions derived from Beatty and McCroskey\u27s model, and (2) the results for E were indicative of a purely reactive function of trait verbal aggressiveness. Implications for theory and research are discussed

Laboratory toxicity studies demonstrate no adverse effects of Cry1Ab and Cry3Bb1 to larvae of Adalia bipunctata (Coleoptera: Coccinellidae): the importance of study design

Scientific studies are frequently used to support policy decisions related to transgenic crops. Schmidt et al., Arch Environ Contam Toxicol 56:221–228 (2009) recently reported that Cry1Ab and Cry3Bb were toxic to larvae of Adalia bipunctata in direct feeding studies. This study was quoted, among others, to justify the ban of Bt maize (MON 810) in Germany. The study has subsequently been criticized because of methodological shortcomings that make it questionable whether the observed effects were due to direct toxicity of the two Cry proteins. We therefore conducted tritrophic studies assessing whether an effect of the two proteins on A. bipunctata could be detected under more realistic routes of exposure. Spider mites that had fed on Bt maize (events MON810 and MON88017) were used as carriers to expose young A. bipunctata larvae to high doses of biologically active Cry1Ab and Cry3Bb1. Ingestion of the two Cry proteins by A. bipunctata did not affect larval mortality, weight, or development time. These results were confirmed in a subsequent experiment in which A. bipunctata were directly fed with a sucrose solution containing dissolved purified proteins at concentrations approximately 10 times higher than measured in Bt maize-fed spider mites. Hence, our study does not provide any evidence that larvae of A. bipunctata are sensitive to Cry1Ab and Cry3Bb1 or that Bt maize expressing these proteins would adversely affect this predator. The results suggest that the apparent harmful effects of Cry1Ab and Cry3Bb1 reported by Schmidt et al., Arch Environ Contam Toxicol 56:221–228 (2009) were artifacts of poor study design and procedures. It is thus important that decision-makers evaluate the quality of individual scientific studies and do not view all as equally rigorous and relevant

An Empirical Test of a Communibiological Model of Trait Verbal Aggressiveness

The purpose of this study was to test Beatty and McCroskey\u27s communibiological model of trait verbal aggressiveness. In general, this model views trait verbal aggressiveness as an expression of temperament; specifically, that trait verbal aggressiveness represents low thresholds for the fight or flight (FFS) neurobiological system. This model further contends that behavioral inhibition circuitry (BIS) moderates FFS activation by tempering aggressive impulses, otherwise FFS activation would manifest itself in the form of physical rather than verbal attacks. Beatty and McCroskey (1997) propose that low thresholds for stimulating the behavioral activation system (BAS) should be related to trait verbal aggressiveness to the extent that the construct involves a proactive rather than a purely reactive interpersonal function. Because previous research indicated that psychoticism (P), neuroticism (N) and extroversion (E) represent psychological manifestations of the FFS, BIS, and BAS systems, respectively, hypotheses linking P, N, and E to trait verbal aggressiveness (VAS) were tested. A multiple regression equation based on disattenuated correlations explained approximately 46% of the variance in VAS scores. Specifically, (1) the results for P and N were consistent with predictions derived from Beatty and McCroskey\u27s model, and (2) the results for E were indicative of a purely reactive function of trait verbal aggressiveness. Implications for theory and research are discussed

Dose dependent establishment of subclinical S. typhimurium infection in pigs and protection against homologous re-challenge

The fact that the majority of Salmonella infected pig herds are subclinically infected is accepted worldwide. In subclinically infected herds shedding of salmonella from infected pigs and the contamination of the environment is markedly below the level known from herds having experienced a clinical outbreak (Baggesen et al., 1996)