Bayesian Inference of Online Social Network Statistics via Lightweight Random Walk Crawls

Online social networks (OSN) contain extensive amount of information about the underlying society that is yet to be explored. One of the most feasible technique to fetch information from OSN, crawling through Application Programming Interface (API) requests, poses serious concerns over the the guarantees of the estimates. In this work, we focus on making reliable statistical inference with limited API crawls. Based on regenerative properties of the random walks, we propose an unbiased estimator for the aggregated sum of functions over edges and proved the connection between variance of the estimator and spectral gap. In order to facilitate Bayesian inference on the true value of the estimator, we derive the approximate posterior distribution of the estimate. Later the proposed ideas are validated with numerical experiments on inference problems in real-world networks

Normal Values of Nasal Nitric Oxide Measured With a Handheld Analyzer in Adults

Background: Nasal nitric oxide (nNO) is decreased in patients with primary ciliary dyskinesia (PCD) as compared to healthy subjects (HS). nNO measurement has been proposed as a screening tool for PCD, but NO analyzers are not widely available and reference values are lacking. Objectives: to determine the normal values of nNO in adults using a widely-used hand-held NO analyzer, and explore correlations with ambient NO, age, gender, weight, height, body mass index (BMI), and time of measurements. Methods: in a pilot phase, 25 adult HS had nNO sampled during breath hold (BH), tidal mouth breathing through a fixed resistance (straw, TB-S) and tidal breathing through a continuous positive airway pressure apparatus (TB-CPAP). TB-S was the most reproducible and comfortable sampling technique and was chosen to measure nNO in 200 adult HS of both genders aged 20 to 80 years, and in 7 adults with PCD. Results: In HS, mean nNO adjusted for ambient NO was 517 ± 226 ppb and was negatively correlated with age (! = -3.76, p = 10-4). No correlation was found with gender, weight, height, BMI, month of the year, and time of the day. The lower limit of normal nNO (2.5th centile) decreased from 201 ppb at age 20 to 46 ppb at age 80. 6 out of 7 PCD patients had nNO below lower limit of normal. Conclusions: nNO values significantly decrease with age in adult HS. Reference values are available to use a handheld nNO analyzer as a screening tool for PCD in adults

Extensive Characterization of Seismic Laws in Acoustic Emissions of Crumpled Plastic Sheets

Statistical similarities between earthquakes and other systems that emit cracking noises have been explored in diverse contexts, ranging from materials science to financial and social systems. Such analogies give promise of a unified and universal theory for describing the complex responses of those systems. There are, however, very few attempts to simultaneously characterize the most fundamental seismic laws in such systems. Here we present a complete description of the Gutenberg-Richter law, the recurrence times, Omori's law, the productivity law, and Bath's law for the acoustic emissions that happen in the relaxation process of uncrumpling thin plastic sheets. Our results show that these laws also appear in this phenomenon, but (for most cases) with different parameters from those reported for earthquakes and fracture experiments. This study thus contributes to elucidate the parallel between seismic laws and cracking noises in uncrumpling processes, revealing striking qualitative similarities but also showing that these processes display unique features.Comment: Accepted for publication in EP