Slingshot non-sequential double ionization as a gate to anti-correlated two electron escape

At intensities below-the-recollision threshold, we show that re-collision-induced excitation with one electron escaping fast after re-collision and the other electron escaping with a time delay via a Coulomb slingshot motion is one of the most important mechanisms of non-sequential double ionization, for strongly-driven He at 400 nm. Slingshot-NSDI is a general mechanism present for a wide range of low intensities and pulse durations. Anti-correlated two-electron escape is its striking hallmark. This mechanism offers an alternative explanation of anti-correlated two-electron escape obtained in previous studies.Comment: 6 pages, 3 figure

Evaluation of food photographs assessing the dietary intake of children up to 10 years old

OBJECTIVE: Young children lack basic skills related to recognizing the types of foods they consume and dietary surveys often rely on parents' response. The present study aimed to evaluate how well parents of children aged from 3 months to 10 years perceive images of portions of foods commonly consumed by young children. DESIGN: Pre-weighed, actual food portions (n 2314) were shown to the study participants who were asked to indicate the picture that corresponded to the food in view. Mean differences between picture numbers selected and shown were estimated and compared using unpaired t tests or Tukey-Cramer pairwise comparisons. SETTING: Real-time testing of parents' perception of food images presenting portion sizes consumed by children up to 10 years old. SUBJECTS: A convenience sample of 138 parents/caregivers of young children (69 % females). RESULTS: Individuals selected the correct or adjacent image in about 97 % of the assessments. Images presenting amorphous solids (i.e. pies and pastries with a filling), liquid or semi-liquid dishes (i.e. soups, porridges, fruit and vegetable purées) were more prone to bias. There was no indication that personal characteristics (gender, age, educational background, age, number of offspring) were associated with differences in the way parents/caregivers perceived the food pictures. CONCLUSIONS: Food pictures may not be appropriate to quantify the intake of liquid, semi-liquid or amorphous solid foods in surveys addressing young children and studies evaluating their performance as food portion anchors should ensure the inclusion of several and various amorphous foods in the assessment

Progress in noncommutative function theory

In this expository paper we describe the study of certain non-self-adjoint operator algebras, the Hardy algebras, and their representation theory. We view these algebras as algebras of (operator valued) functions on their spaces of representations. We will show that these spaces of representations can be parameterized as unit balls of certain $W^{*}$-correspondences and the functions can be viewed as Schur class operator functions on these balls. We will provide evidence to show that the elements in these (non commutative) Hardy algebras behave very much like bounded analytic functions and the study of these algebras should be viewed as noncommutative function theory

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum