Statistical Modeling and Markov Chain Monte Carlo Inference of the MAJORANA DEMONSTRATOR Background Data

Observation of neutrinoless double-beta decay (0νββ) would establish lepton number violation, constrain the absolute neutrino mass scale, and imply the Majorana nature of neutrinos. Germanium-based 0νββ experiments are entering the tonne-scale era with discovery potential for half lives approaching 10^28 years, covering the region of effective Majorana neutrino masses indicative of the inverted ordering scenario for the three neutrino mass eigenstates. Sensitivity to such protracted decay rates requires < 0.1 background counts in the signal region per tonne-year of an experiment’s exposure, an order of magnitude improvement from current experiments observing tens of kilograms of 76Ge. Toward this goal, this work describes the simulation and analysis of 26.0 kilogram-years of background data from the MAJORANA DEMONSTRATOR, a 0νββ experiment operating an array of high-purity germanium detectors in a low-background environment at the Sanford Underground Research Facility. A latest analysis of this data yields a half life sensitivity of 4.8 × 10^25 years. Detailed simulation of the DEMONSTRATOR design and constraints on the radiopurity of its components facilitate Bayesian statistical modeling of the background data and Markov chain Monte Carlo sampling for inference of background sources, essential inputs for the next-generation tonne-scale experiment LEGEND.Doctor of Philosoph

Inverse-power-law behavior of cellular motility reveals stromal–epithelial cell interactions in 3D co-culture by OCT fluctuation spectroscopy

The progression of breast cancer is known to be affected by stromal cells within the local microenvironment. Here we study the effect of stromal fibroblasts on the in-place motions (motility) of mammary epithelial cells within organoids in 3D co-culture, inferred from the speckle fluctuation spectrum using optical coherence tomography (OCT). In contrast to Brownian motion, mammary cell motions exhibit an inverse power-law fluctuation spectrum. We introduce two complementary metrics for quantifying fluctuation spectra: the power-law exponent and a novel definition of the motility amplitude, both of which are signal- and position-independent. We find that the power-law exponent and motility amplitude are positively (p<0.001) and negatively (p<0.01) correlated with the density of stromal cells in 3D co-culture, respectively. We also show how the hyperspectral data can be visualized using these metrics to observe heterogeneity within organoids. This constitutes a simple and powerful tool for detecting and imaging cellular functional changes with OCT

Le Bonhomme mayennais : journal de Lassay, Pré-en-Pail et cantons voisins ["puis" journal de Lassay, Pré-en-Pail, des cantons voisins et du département]...

06 décembre 18851885/12/06 (A3,N116)-1885/12/06.Appartient à l’ensemble documentaire : BNormand

Outbreak of cryptosporidiosis at a California waterpark: employee and patron roles and the long road towards prevention

In August–September 2004, a cryptosporidiosis outbreak affected >250 persons who visited a California waterpark. Employees and patrons of the waterpark were affected, and three employees and 16 patrons admitted to going into recreational water while ill with diarrhoea. The median illness onset date for waterpark employees was 8 days earlier than that for patrons. A case-control study determined that getting water in one’s mouth on the waterpark’s waterslides was associated with illness (adjusted odds ratio 7·4, 95% confidence interval 1·7–32·2). Laboratory studies identified Cryptosporidium oocysts in sand and backwash from the waterslides’ filter, and environmental investigations uncovered inadequate water-quality record keeping and a design flaw in one of the filtration systems. Occurring more than a decade after the first reported outbreaks of cryptosporidiosis in swimming pools, this outbreak demonstrates that messages about healthy swimming practices have not been adopted by pool operators and the public