Does the magnetosphere behave differently on weekends?

International audienceGlobal geomagnetic activity has been suggested to be enhanced during weekends above the weekly average after 1930. Before the 1930s, weekends and weekdays were found to be equally active. This so-called "weekend effect" was suggested to be due to power line harmonic radiation (PLHR) in the VLF range emitted by electric power lines. Since the consumption of electric power is different on weekends and weekdays, leading to different PLHR intensities, this could possibly cause the "weekend effect" in global geomagnetic activity. In the present paper, we reanalyse the suggested "week-end effect" in global geomagnetic activity using the 69-year planetary geomagnetic Ap index and the 131-year antipodal aa index. We conclude that there is no statistically significant "weekend effect" during the interval covered by these geo-magnetic activity indices. Although global geomagnetic activity is slightly enhanced on weekends from the 1930s to the 1980s, the more recent data show rather a relative decrease in global geomagnetic activity on weekends, contrary to the expected increase in the "weekend effect", due to increasing power consumption. Moreover, the weekly distribution is fairly similar in solar wind speed and global geomagnetic activity during the last 35 years, further supporting the view that the "weekend effect" is only a statistical fluctuation

Citizens’ opinions on (non-)essential uses of persistent chemicals: A survey in seven European countries

In accordance with the European Chemicals Strategy for Sustainability towards a Toxic-free Environment, the European Commission plans to phase out persistent chemicals, such as per- and polyfluoroalkyl substances (PFASs), except for uses classified essential for society. Until now, empirical research on what is considered an essential or non-essential chemical use has been lacking. Furthermore, as such criteria are bound to be subjective, different parties can have different views. In this study we explored which uses of persistent chemicals citizens from seven EU countries consider (non-)essential for society. As EU citizens are directly impacted by policy decisions based on (non-)essentiality criteria, we also investigated the influence of emphasis on the consequences of banning vs. allowing persistent chemicals, the association with demographics, and of having heard of persistent chemicals or PFAS prior to the study. We found substantial variation in essentiality ratings within and between use categories and between countries. Uses related to safety were frequently considered essential, whereas uses related to recreation, household, and personal care were frequently considered non-essential. Emphasis on different consequences did not influence essentiality ratings. Gender, age, education, and political orientation were to some extent associated with essentiality ratings. People who had not heard of persistent chemicals or PFAS prior to the study rated uses of persistent chemicals less frequently as non-essential or essential. Our findings offer insight into EU citizens’ opinions on (non-)essential uses of persistent chemicals, and provide empirical input to the scientific and public debate on framing the concept of essential use.</p

Development of high-speed directly-modulated DFB and DBR lasers with surface gratings

The conventional distributed feedback and distributed Bragg reflector edge-emitting lasers employ buried gratings, which require two or more epitaxial growth steps. By using lateral corrugations of the ridge-waveguide as surface gratings the epitaxial overgrowth is avoided, reducing the fabrication complexity, increasing the yield and reducing the fabrication cost. The surface gratings are applicable to different materials, including Al-containing ones and can be easily integrated in complex device structures and photonic circuits. Single-contact and multiple contact edge-emitting lasers with laterally-corrugated ridge waveguide gratings have been developed both on GaAs and InP substrates with the aim to exploit the photon-photon resonance in order to extend their direct modulation bandwidth. The paper reports on the characteristics of such surface-grating-based lasers emitting both at 1.3 and 1.55 μm and presents the photon-photon resonance extended small-signal modulation bandwidth (> 20 GHz) achieved with a 1.6 mm long single-contact device under direct modulation. Similarly structured devices, with shorter cavity lengths are expected to exceed 40 GHz smallsignal modulation bandwidth under direct modulatio

Anthropogenic Space Weather

Anthropogenic effects on the space environment started in the late 19th century and reached their peak in the 1960s when high-altitude nuclear explosions were carried out by the USA and the Soviet Union. These explosions created artificial radiation belts near Earth that resulted in major damages to several satellites. Another, unexpected impact of the high-altitude nuclear tests was the electromagnetic pulse (EMP) that can have devastating effects over a large geographic area (as large as the continental United States). Other anthropogenic impacts on the space environment include chemical release ex- periments, high-frequency wave heating of the ionosphere and the interaction of VLF waves with the radiation belts. This paper reviews the fundamental physical process behind these phenomena and discusses the observations of their impacts.Comment: 71 pages, 35 figure

Anduril 2: Upgraded large-scale data integration framework

aSummary: Anduril is an analysis and integration framework that facilitates the design, use, parallelization and reproducibility of bioinformatics workflows. Anduril has been upgraded to use Scala for pipeline construction, which simplifies software maintenance, and facilitates design of complex pipelines. Additionally, Anduril's bioinformatics repository has been expanded with multiple components, and tutorial pipelines, for next-generation sequencing data analysis.Peer reviewe

Chlamydiatrachomatis and placental inflammation in early preterm delivery

Chlamydiatrachomatis may infect the placenta and subsequently lead to preterm delivery. Our aim was to evaluate the relationship between the presence of Chlamydiatrachomatis and signs of placental inflammation in women who delivered at 32 weeks gestation or less. Setting: placental histology and clinical data were prospectively obtained from 304 women and newborns at the Erasmus MC-Sophia, Rotterdam, the Netherlands. C.trachomatis testing of placentas was done retrospectively using PCR. C.trachomatis was detected in 76 (25%) placentas. Histological evidence of placental inflammation was present in 123 (40%) placentas: in 41/76 (54%) placentas with C.trachomatis versus 82/228 (36%) placentas without C.trachomatis infection (OR 2.1, 95% CI 1.2–3.5). C.trachomatis infection correlated with the progression (P = 0.009) and intensity (P = 0.007) of materno-fetal placental inflammation. C.trachomatis DNA was frequently detected in the placenta of women with early preterm delivery, and was associated with histopathological signs of placental inflammation