Jet Charge at the LHC

Knowing the charge of the parton initiating a light-quark jet could be extremely useful both for testing aspects of the Standard Model and for characterizing potential beyond-the-Standard-Model signals. We show that despite the complications of hadronization and out-of-jet radiation such as pile-up, a weighted sum of the charges of a jet's constituents can be used at the LHC to distinguish among jets with different charges. Potential applications include measuring electroweak quantum numbers of hadronically decaying resonances or supersymmetric particles, as well as Standard Model tests, such as jet charge in dijet events or in hadronically-decaying W bosons in t-tbar events. We develop a systematically improvable method to calculate moments of these charge distributions by combining multi-hadron fragmentation functions with perturbative jet functions and pertubative evolution equations. We show that the dependence on energy and jet size for the average and width of the jet charge can be calculated despite the large experimental uncertainty on fragmentation functions. These calculations can provide a validation tool for data independent of Monte-Carlo fragmentation models.Comment: 5 pages, 6 figures; v2 published versio

Population Dynamics of Endangered Iresine Rhizomatosa (Juda’s Bush)

Population changes of Iresine rhizomatosa Standl. (Juda’s bush, bloodleaf: Amaranthaceae) a State listed (Endangered in Illinois and Maryland, Rare in Indiana) perennial bush of floodplain forests is reported. The size/stage class distribution of I. rhizomatosa plants in Beall Woods and Robeson Hills, Illinois was determined to assess the proportional representation of individuals of different sizes, and monitor fecundity. One hundred randomly located individuals were tagged in each population in March 2012 and monitored for two years. Seedling emergence was monitored from fall 2012 through spring 2013. The number of flowering spikes, and numbers of seed produced were monitored on randomly selected adult plants in fall 2012. Survivorship of seedlings was low (\u3c 50%), re-growth of plants was poor, and seeds had low viability (8-12%) and germination rate (\u3c 1%); all features consistent with the rare status of this state-endangered plant. As a perennial, this plant is buffered to some extent against periods of poor recruitment, but populations would be at risk if these coincided with periods of high adult mortality

Uncertainty Monitoring by Young Children in a Computerized Task

Adult humans show sophisticated metacognitive abilities, including the ability to monitor uncertainty. Unfortunately, most measures of uncertainty monitoring are limited to use with adults due to their general complexity and dependence on explicit verbalization. However, recent research with nonhuman animals has successfully developed measures of uncertainty monitoring that are simple and do not require explicit verbalization. The purpose of this study was to investigate metacognition in young children using uncertainty monitoring tests developed for nonhumans. Children judged whether stimuli were more pink or blue—stimuli nearest the pink-blue midpoint were the most uncertain and the most difficult to classify. Children also had an option to acknowledge difficulty and gain the necessary information for correct classification. As predicted, children most often asked for help on the most difficult stimuli. This result confirms that some metacognitive abilities appear early in cognitive development. The tasks of animal metacognition research clearly have substantial utility for exploring the early developmental roots of human metacognition