10,645 research outputs found
Comment on "Including Systematic Uncertainties in Confidence Interval Construction for Poisson Statistics"
The incorporation of systematic uncertainties into confidence interval
calculations has been addressed recently in a paper by Conrad et al. (Physical
Review D 67 (2003) 012002). In their work, systematic uncertainities in
detector efficiencies and background flux predictions were incorporated
following the hybrid frequentist-Bayesian prescription of Cousins and Highland,
but using the likelihood ratio ordering of Feldman and Cousins in order to
produce "unified" confidence intervals. In general, the resulting intervals
behaved as one would intuitively expect, i.e. increased with increasing
uncertainties. However, it was noted that for numbers of observed events less
than or of order of the expected background, the intervals could sometimes
behave in a completely counter-intuitive fashion -- being seen to initially
decrease in the face of increasing uncertainties, but only for the case of
increasing signal efficiency uncertainty. In this comment, we show that the
problematic behaviour is due to integration over the signal efficiency
uncertainty while maximising the best fit alternative hypothesis likelihood. If
the alternative hypothesis likelihood is determined by unconditionally
maximising with respect to both the unknown signal and signal efficiency
uncertainty, the limits display the correct intuitive behaviour.Comment: Submitted to Physical Review
Script Fading and Training: Evaluating the Necessity of Visual Cues to Teach Contextually Appropriate Play Commenting
Autism Spectrum Disorder (ASD) is marked by many areas of need, including play and communication. These areas of concern can have a negative impact on a child\u27s development. Applied behavior analysis, specifically script training and fading procedures, has shown promise in teaching communication during play to young autistic children. However, traditional script training and fading methods have some limitations, including the skills the children already possess to learn the scripts and the resources needed to teach the scripts. Recent studies have shown that script frames can be taught without using traditional training formats (i.e., text, auditory) but by using generic picture cues. Thus, the current study aimed to evaluate the necessity of visual cues in teaching contextually appropriate play commenting in preschool-aged children with ASD. The potential impact of this research on the field of autism and child development is significant, as it could lead to more effective teaching methods for autistic children. The results of the current study provide further evidence for the use of generic picture cues to teach contextually appropriate play commenting. In addition, it shows that teaching scripted responses can lead to an increase in the emission of novel play comments. Unfortunately, one participant was withdrawn due to challenges encountered while teaching the script frames and time constraints
Use of magnetic and olfactory cues for orientation by a fossorial rodent, Thomomys talpoides
Fossorial, or below ground, living provides shelter from the elements and some predators, but comes at a cost with respect to metabolic requirements of movement and reduced, or altered, sensory cues. I examined the ability of the North American pocket gopher, Thomomys talpoides, to use magnetoreception and olfaction in navigation and foraging. Magnetoreception was tested using three manipulative experiments: 1) field homing of displaced animals, 2) nest location in an 8-arm maze, and 3) movement through a complex labyrinth. Homing results, analyzed by V-test, indicated that the gophers displaced from their burrow systems relied on magnetic cues for homing orientation. Although Rayleigh analysis of the 8-arm maze tests showed limited significance, gophers tended to nest in the conditioned direction, and nesting direction shifted with an altered field. Repeated Measures ANOVA results of performance in time and number of wrong turns in the complex labyrinth showed no significant differences between conditioned trials (unaltered-field) and test (field rotated 90°) trials. Use of olfaction was tested in T-maze trials with soils containing carrot kairomone versus control soil. Binomial probability analysis revealed in all tests comparing carrot soil vs. control that gophers disproportionally selected the carrot soils. Overall my study suggests T talpoides can use both magnetic and olfactory cues while navigating, but the use of these cues is situation dependent. These results are similar to those found in other South American and Old World fossorial rodents --Document
Treatment of the background error in the statistical analysis of Poisson processes
The formalism that allows to take into account the error sigma_b of the
expected mean background b in the statistical analysis of a Poisson process
with the frequentistic method is presented. It is shown that the error sigma_b
cannot be neglected if it is not much smaller than sqrt(b). The resulting
confidence belt is larger that the one for sigma_b=0, leading to larger
confidence intervals for the mean mu of signal events.Comment: 15 pages including 2 figures, RevTeX. Final version published in
Phys. Rev. D 59 (1999) 11300
Low-level seaweed supplementation improves iodine status in iodine-insufficient women
Iodine insufficiency is now a prominent issue in the UK and other European countries due to low intakes of dairy products and seafood (especially where iodine fortification is not in place). In the present study, we tested a commercially available encapsulated edible seaweed (Napiers Hebridean Seagreens® Ascophyllum nodosumspecies) for its acceptability to consumers and iodine bioavailability and investigated the impact of a 2-week daily seaweed supplementation on iodine concentrations and thyroid function. Healthy non-pregnant women of childbearing age, self-reporting low dairy product and seafood consumption, with no history of thyroid or gastrointestinal disease were recruited. Seaweed iodine (712 μg, in 1 g seaweed) was modestly bioavailable at 33 (interquartile range (IQR) 28–46) % of the ingested iodine dose compared with 59 (IQR 46–74) % of iodine from the KI supplement (n 22). After supplement ingestion (2 weeks, 0•5 g seaweed daily, <i>n</i> 42), urinary iodine excretion increased from 78 (IQR 39–114) to 140 (IQR 103–195) μg/l (<i>P</i>< 0•001). The concentrations of thyroid-stimulating hormone increased from 1•5 (IQR 1•2–2•2) to 2•1 (IQR 1•3–2•9) mIU/l (<i>P</i>< 0•001), with two participants having concentrations exceeding the normal range after supplement ingestion (but normal free thyroxine concentrations). There was no change in the concentrations of other thyroid hormones after supplement ingestion. The seaweed was palatable and acceptable to consumers as a whole food or as a food ingredient and effective as a source of iodine in an iodine-insufficient population. In conclusion, seaweed inclusion in staple foods would serve as an alternative to fortification of salt or other foods with KI
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