Modeling probability density through ultraspherical polynomial transformations

Abstract We present a method for fitting parametric probability density models using an integrated square error criterion on a continuum of weighted Lebesgue spaces formed by ultraspherical polynomials. This approach is inherently suitable for creating mixture model representations of complex distributions and allows fully autonomous cluster analysis of high-dimensional datasets. The method is also suitable for extremely large sets, allowing post facto model selection and analysis even in the absence of the original data. Furthermore, the fitting procedure only requires the parametric model to be pointwise evaluable, making it trivial to fit user-defined models through a generic algorithm

A survey of water production in 61 comets from SOHO/SWAN observations of hydrogen Lyman-alpha: Twenty-one years 1996–2016

International audienceThe Solar Wind Anisotropies (SWAN) instrument on the SOlar and Heliospheric Observatory (SOHO) satellite has observed 44 long period and new Oort cloud comets and 36 apparitions of 17 short period comets since its launch in December 1995. Water production rates have been determined from the over 3700 images producing a consistent set of activity variations over large parts of each comet's orbit. This has enabled the calculation of exponential power-law variations with heliocentric distance of these comets both before and after perihelion, as well as the absolute values of the water production rates. These various measures of overall water activity including pre- and post-perihelion exponents, absolute water production rates at 1 AU, active surface areas and their variations have been compared with a number of dynamical quantities for each comet including dynamical class, original semi-major axis, nucleus radius (when available), and compositional taxonomic class. Evidence for evolution of cometary nuclei is seen in both long-period and short-period comets

Stochastic continuum approach to high-cycle fatigue:modelling stress history as a stochastic process

Abstract In this article, the continuum-based high-cycle fatigue analysis method, introduced by Ottosen, Stenström and Ristinmaa in 2008, is extended to cases where the stress history is a stochastic process. The basic three-parameter Ornstein–Uhlenbeck process is chosen for stress description. As a practical example, the theory is applied in both finite and infinite life cases. A definition for the safety factor is introduced, which is reduced to a minimization problem of the value for the endurance surface. In the stochastic case, the values of the endurance surface form a stochastic process and the cumulative distribution function can be constructed for its maximum values

Social-pragmatic inferencing, visual social attention and physiological reactivity to complex social scenes in autistic young adults

Abstract This study examined social-pragmatic inferencing, visual social attention and physiological reactivity to complex social scenes. Participants were autistic young adults (n = 14) and a control group of young adults (n = 14) without intellectual disability. Results indicate between-group differences in social-pragmatic inferencing, moment-level social attention and heart rate variability (HRV) reactivity. A key finding suggests associations between increased moment-level social attention to facial emotion expressions, better social-pragmatic inferencing and greater HRV suppression in autistic young adults. Supporting previous research, better social-pragmatic inferencing was found associated with less autistic traits

Diet as a Risk Factor for Pneumococcal Carriage and Otitis Media: A Cross-Sectional Study among Children in Day Care Centers

Pharyngeal bacteria are exposed to different sugar conditions depending on the diet of the child. We hypothesized that dietary factors such as daily intake of carbohydrates could be associated with pneumococcal carriage and the occurrence of otitis media in children.Our study design was a cross-sectional study among 1006 children attending child day care centers. Parents filled in a food frequency questionnaire. Oropharyngeal swabs were collected from each child. The primary outcome was the occurrence of pneumococcal carriage and the secondary outcome the number of acute otitis media episodes during life. Principal component analysis was used to group dietary intake into nine factors. The models were adjusted for age, gender of the child and educational level of the mother.The dietary factor which included high consumption of sweet pastries and jam was associated with an increased risk of pneumococcal carriage (OR 1.17, 95% CI 1.01 to 1.36, P-value 0.04). The factor including frequent consumption of fruit and berries was associated with a decreased risk of acute otitis (regression coefficient -0.51, 95% CI -0.98 to -0.03, P=0.04). A high intake of consumption of sweets and snacks (OR 1.36, 95% CI 1.03 to 1.80, P=0.03) was associated with an increased risk of caries.Diet was associated with a risk of pneumococcal carriage and the occurrence of otitis media. Diet may thus be a modifiable risk factor for the occurrence of acute otitis media

Observations of the climate near the surface of Jezero over a half Mars year

International audiencePerseverance landed on Jezero with the most complete suite of environmental sensors ever sent to the surface of another planet. It combines the Mars Environmental Dynamics Analyzer (MEDA), the MastCam-Z and Engineering cameras, SuperCam spectrometers and, finally, the several microphones onboard the Mars 2020 rover. The most recent collection of atmospheric observations at Jezero and their interpretation are building an understanding of what physical processes drive the behavior of the Martian atmosphere near the surface of Jezero. We report on the observed Martian cycles of pressure, temperature, dust opacity with their physical aerosol properties, and the hydrological cycle at Jezero. These cycles have shown different behaviors on time scales from diurnal to seasonal and annual to other locations where we landed before. The differences illustrate the range of environmental processes that one can find near the red planet’s surface. We also report on the observed evolution of the near-surface boundary layer thermodynamics during the day and nighttime regimes