Quantum field theory predicts a nonlinear response of the vacuum to strong electromagnetic fields of macroscopic extent. This fundamental tenet has remained experimentally challenging and is yet to be tested in the laboratory. A particularly distinct signature of the resulting optical activity of the quantum vacuum is vacuum birefringence. This offers an excellent opportunity for a precision test of nonlinear quantum electrodynamics in an uncharted parameter regime. Recently, the operation of the high-intensity Relativistic Laser at the X-ray Free Electron Laser provided by the Helmholtz International Beamline for Extreme Fields has been inaugurated at the High Energy Density scientific instrument of the European X-ray Free Electron Laser. We make the case that this worldwide unique combination of an X-ray free-electron laser and an ultra-intense near-infrared laser together with recent advances in high-precision X-ray polarimetry, refinements of prospective discovery scenarios and progress in their accurate theoretical modelling have set the stage for performing an actual discovery experiment of quantum vacuum nonlinearity.

In a number of studies, it has been shown that subjects with attention-deficit/hyperactivity disorder (ADHD) show deficits in executive functioning, i.e. in cognitive functions that subserve planning, monitoring and control of goal-directed behaviour (Martinussen et al., 2005; Willcutt et al., 2005), as well as in emotion regulation (Berlin et al., 2004; Desman et al., 2006). However, no study exists so far examining the interaction between cognition and emotion regulation in subjects with ADHD. In our study, we aimed to examine to what extend arousing emotional picture stimuli may account for differential effects in performance quality in subjects with and without ADHD. Thirty-nine males and females with ADHD aged 18 to 40 years and 40 matched healthy controls performed a working memory n-back task (1-back, 2-back). The task was performed with and without neutral and negative background pictures from the International Affective Picture System (IAPS) which varied in arousal (low, medium, high). Irrespective of ADHD diagnosis, all subjects were slower and demonstrated lower performance accuracy in the 2-back condition compared with the 1-back condition, and all subjects deteriorated with increasing picture arousal. In comparison to healthy controls, subjects with ADHD displayed a deficit in working memory performance in terms of prolonged reaction times and decreased performance accuracy. Beyond this, we found that whereas healthy controls did not display performance deficits until they were presented with high-arousal background pictures, subjects with ADHD were already impaired when presented with medium-arousal background pictures. The implications of these and further findings will be discussed.

Adsorption of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] and fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] on a Taloka silt loam (Mollic Albaqualf) and a Roxana silt loam (Typic Udifluvent) from the 10- to 20- and 40- to 50-cm soil depths was measured. The order of adsorption of the herbicides was fluometuron = metolachlor > metribuzin. Adsorptivity of the soil from the 10- to 20-cm depth was greater than from the 40- to 50-cm depth. At 7, 15, 23, and 37C, all herbicides degraded more rapidly as temperature increased. Metribuzin was least persistent and fluometuron and metolachlor were similarly persistent. The time required for the initial herbicide concentration to decrease by 50% in the Taloka silt loam from the 10- to 20-cm depth at 23C was 2.6, 9.4, and 10.1 weeks for metribuzin, fluometuron, and metolachlor, respectively.

The terminal lake systems of central Australia are key sites for the reconstruction of late Quaternary paleoenvironments. Paleoshoreline deposits around these lakes reflect repeated lake filling episodes and such landforms have enabled the establishment of a luminescence-based chronology for filling events in previous studies. Here we present a detailed documentation of the morphology and chemistry of soils developed in four well-preserved beach ridges of late Pleistocene and mid-to-late Holocene age at Lake Callabonna to assess changes in dominant pedogenic processes. All soil profiles contain evidence for the incorporation of eolian-derived material, likely via the formation of desert pavements and vesicular horizons, and limited illuviation due to generally shallow wetting fronts. Even though soil properties in the four studied profiles also provide examples of parent material influence or site-specific processes related to the geomorphic setting, there is an overall trend of increasing enrichment of eolian-derived material since at least ~ 33 ka. Compared to the Holocene profiles, the derived average accumulation rates for the late Pleistocene profiles are significantly lower and may suggest that soils record important regional changes in paleoenvironments and dust dynamics related to shifts in the Southern Hemisphere westerlies.

We survey the theory of quasi-periodic Schrödinger-type operators, focusing on the advances made since the early 2000s by adopting a dynamical systems point of view.

Purpose: This study aims to evaluate the health-related quality of life of adolescents with congenital heart disease, describing health-related quality of life according to the diagnosis and severity of congenital heart disease, identified by variables such as the presence of symptoms, surgical interventions, use of medication, and residual lesion. Methods: A cross-sectional study was conducted on 203 adolescents with congenital heart disease attended at the Pediatric Cardiology ambulatory of a reference hospital in Brazil. The Brazilian version of the questionnaire KIDSCREEN-27 was used for the assessment of health-related quality of life. Information related to the congenital heart disease diagnosis and clinical variables were collected from the medical records of the patients. Results: There was no statistically significant difference between acyanotic and cyanotic groups, as well as for the different diagnosis of congenital heart disease. A trend for better health-related quality of life in the dimension of Psychological Well-Being (p=0.054) was found in the groups with surgical intervention and use of medication. Adolescents that referred a good general health presented significantly better results in all dimensions of health-related quality of life, except for Autonomy and Parent Relation, than those who presented clinical symptoms (p<0.05). Conclusions: Type of congenital heart disease and initial diagnosis did not seem to affect the perception of health-related quality of life, corroborating findings of several studies. Surgical interventions and the use of medication can improve previous clinical status, and therefore it seems to be beneficial in terms of Psychological Well-Being. The presence of clinical symptoms was the variable that caused the largest impact on the perception of health-related quality of life, possibly because of the impairment they bring to the daily lives of these patients.