The European risk from geomagnetically induced currents (EURISGIC)

EURISGIC (www.eurisgic.eu) was the first continental-scale study of the geomagnetically induced current (GIC) hazard to Europe’s power transmission system. EURISGIC had a number of strands to it, including modelling GIC in the European system and understanding the possible extremes that the system could face. These project strands were represented by nine distinct work packages: • The construction of the first ever European power transmission grid model and an update of the existing UK model • The development of detailed conductivity models for Europe and, separately, the UK • The building of geomagnetic, GIC and related science databases • The production of a GIC risk map for Europe • The investigation of worst case scenarios and extremes in the grid models • The development of the NASA ‘Solar Shield’ magnetospheric and solar wind model for use in the European context • The enhancement of a prototype GIC and geomagnetic forecast system for Europe • The making of geomagnetic, geoelectric and GIC measurements to enhance our knowledge and validate models • The education of the public and other stakeholders through scientific papers and other materials. To assess and guide progress on the project a team of industry advisors was assembled. These advisors included senior power engineers from major electrical transmission system operators from across Europe, including National Grid in the UK. In this poster we demonstrate some of the major findings of the project. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 260330

The evolutionary trajectory of the mating-type (mat) genes in Neurospora relates to reproductive behavior of taxa

<p>Abstract</p> <p>Background</p> <p>Comparative sequencing studies among a wide range of taxonomic groups, including fungi, have led to the discovery that reproductive genes evolve more rapidly than other genes. However, for fungal reproductive genes the question has remained whether the rapid evolution is a result of stochastic or deterministic processes. The mating-type (<it>mat</it>) genes constitute the master regulators of sexual reproduction in filamentous ascomycetes and here we present a study of the molecular evolution of the four <it>mat</it>-genes (<it>mat a-1</it>, <it>mat A-1</it>, <it>mat A-2 </it>and <it>mat A-3</it>) of 20 <it>Neurospora </it>taxa.</p> <p>Results</p> <p>We estimated nonsynonymous and synonymous substitution rates of genes to infer their evolutionary rate, and confirmed that the <it>mat</it>-genes evolve rapidly. Furthermore, the evolutionary trajectories are related to the reproductive modes of the taxa; likelihood methods revealed that positive selection acting on specific codons drives the diversity in heterothallic taxa, while among homothallic taxa the rapid evolution is due to a lack of selective constraint. The latter finding is supported by presence of stop codons and frame shift mutations disrupting the open reading frames of <it>mat a-1</it>, <it>mat A-2 </it>and <it>mat A-3 </it>in homothallic taxa. Lower selective constraints of <it>mat</it>-genes was found among homothallic than heterothallic taxa, and comparisons with non-reproductive genes argue that this disparity is not a nonspecific, genome-wide phenomenon.</p> <p>Conclusion</p> <p>Our data show that the <it>mat</it>-genes evolve rapidly in <it>Neurospora</it>. The rapid divergence is due to either adaptive evolution or lack of selective constraints, depending on the reproductive mode of the taxa. This is the first instance of positive selection acting on reproductive genes in the fungal kingdom, and illustrates how the evolutionary trajectory of reproductive genes can change after a switch in reproductive behaviour of an organism.</p

The Quiescent Intracluster Medium in the Core of the Perseus Cluster

Clusters of galaxies are the most massive gravitationally-bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and a host of astrophysical processes. Knowledge of the dynamics of the pervasive hot gas, which dominates in mass over stars in a cluster, is a crucial missing ingredient. It can enable new insights into mechanical energy injection by the central supermassive black hole and the use of hydrostatic equilibrium for the determination of cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50 million K diffuse hot plasma filling its gravitational potential well. The Active Galactic Nucleus of the central galaxy NGC1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These likely induce motions in the intracluster medium and heat the inner gas preventing runaway radiative cooling; a process known as Active Galactic Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus cluster core, which reveal a remarkably quiescent atmosphere where the gas has a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s is found across the 60 kpc image of the cluster core. Turbulent pressure support in the gas is 4% or less of the thermodynamic pressure, with large scale shear at most doubling that estimate. We infer that total cluster masses determined from hydrostatic equilibrium in the central regions need little correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July

Hitomi (ASTRO-H) X-ray Astronomy Satellite

The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E  >  2  keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month

Association between convalescent plasma treatment and mortality in COVID-19: a collaborative systematic review and meta-analysis of randomized clinical trials

BACKGROUND: Convalescent plasma has been widely used to treat COVID-19 and is under investigation in numerous randomized clinical trials, but results are publicly available only for a small number of trials. The objective of this study was to assess the benefits of convalescent plasma treatment compared to placebo or no treatment and all-cause mortality in patients with COVID-19, using data from all available randomized clinical trials, including unpublished and ongoing trials (Open Science Framework, https://doi.org/10.17605/OSF.IO/GEHFX ). METHODS: In this collaborative systematic review and meta-analysis, clinical trial registries (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform), the Cochrane COVID-19 register, the LOVE database, and PubMed were searched until April 8, 2021. Investigators of trials registered by March 1, 2021, without published results were contacted via email. Eligible were ongoing, discontinued and completed randomized clinical trials that compared convalescent plasma with placebo or no treatment in COVID-19 patients, regardless of setting or treatment schedule. Aggregated mortality data were extracted from publications or provided by investigators of unpublished trials and combined using the Hartung-Knapp-Sidik-Jonkman random effects model. We investigated the contribution of unpublished trials to the overall evidence. RESULTS: A total of 16,477 patients were included in 33 trials (20 unpublished with 3190 patients, 13 published with 13,287 patients). 32 trials enrolled only hospitalized patients (including 3 with only intensive care unit patients). Risk of bias was low for 29/33 trials. Of 8495 patients who received convalescent plasma, 1997 died (23%), and of 7982 control patients, 1952 died (24%). The combined risk ratio for all-cause mortality was 0.97 (95% confidence interval: 0.92; 1.02) with between-study heterogeneity not beyond chance (I(2) = 0%). The RECOVERY trial had 69.8% and the unpublished evidence 25.3% of the weight in the meta-analysis. CONCLUSIONS: Convalescent plasma treatment of patients with COVID-19 did not reduce all-cause mortality. These results provide strong evidence that convalescent plasma treatment for patients with COVID-19 should not be used outside of randomized trials. Evidence synthesis from collaborations among trial investigators can inform both evidence generation and evidence application in patient care

The Sun, Space Weather and Effects

The Sun and the solar magnetic activity is responsible for a variety of effects in space and on the Earth. High energy radiation and charged particles are constantly being emitted from the solar atmosphere interacting with our atmosphere and technological systems in space and on the ground. The research papers included in this thesis cover analysis of solar magnetic activity, solar indices, solar wind data and geomagnetic data. Also included are calculations of induced currents in power grids from geomagnetic disturbances and prediction of the geomagnetic field. The most common solar index, the sunspot number, was studied as a proxy for the total solar irradiance. The solar magnetic activity, in the form of synoptic maps, was analysed on many time scales from about a day up to several years. The data and the analysing tools used in the papers, wavelets and neural networks, are also briefly described. This doctoral thesis is about space weather and solar-terrestrial physics. It is divided into a summary and five research papers. In the summary I present an outline of the solar-terrestrial environment: The Sun, solar magnetic activity, the heliosphere and the solar wind, geomagnetic storms and ground effects. I also briefly summarise each paper. In the second part all five papers are reprinted. Papers A and B compare induced currents in technological systems, both measured and calculated, with geomagnetic disturbances and other solar-terrestrial data. Paper C use an empirical model, based on neural networks, to predict the local ground magnetic field fluctuations from solar wind data. Paper D, studies the relationship between solar indices and the total solar irradiance using wavelet analysis. Finally, paper E includes a multiresolution analysis of solar synoptic magnetic fields

Performance optimization in MACS

Ericsson Microwave Systems AB in Mölndal is developing a computer concept called MACS (Modular Airborne Computer System) to be used in airborne embedded computer systems. In this master thesis an analysis has been made to find out which parts of the MACS system that are suitable to optimize with respect to performance. A number of different tests have also been made to verify and suggest possible changes. However since this work has been done at the FN/K division at Ericsson Microwave Systems there might be aspects from other divisions, that are working with MACS, that have not been considered that will make such optimizations less appropriate. The main conclusion after these investigations is that the largest bottlenecks already are optimized. Some small possible optimization alternatives have however been found and are described in the report. A proposal given in an earlier thesis about how to increase the performance of the Runtime System has also been investigated and it was found that the gained performance not would not be enough to justify the increased complexity that is the disadvantage of that change. A recommendation of further work is to reorganize the code structure as well as teach the programmers at the department how to write code that the compiler/optimizer would optimize most efficiently. One can however not assume that a coding style that proves to be more efficient on one system also will be more efficient on another. Decisions made for the sake of performance must be made on the basis of testing the alternatives on the actual system on which the application will be fielded. Since this thesis was very loosely defined and no specific tasks were given in advance the work have included a lot of investigation which partly have not led to any results. The investigated system is also very large and a lot of work with optimization had already been done when this work started. The work led however to some recommendations and it also gave a lot of experience.Validerat; 20101217 (root

Exploring Three Recurrent Neural Network Architectures for Geomagnetic Predictions

Three different recurrent neural network (RNN) architectures are studied for the prediction of geomagnetic activity. The RNNs studied are the Elman, gated recurrent unit (GRU), and long short-term memory (LSTM). The RNNs take solar wind data as inputs to predict the Dst index. The Dst index summarizes complex geomagnetic processes into a single time series. The models are trained and tested using five-fold cross-validation based on the hourly resolution OMNI dataset using data from the years 1995–2015. The inputs are solar wind plasma (particle density and speed), vector magnetic fields, time of year, and time of day. The RNNs are regularized using early stopping and dropout. We find that both the gated recurrent unit and long short-term memory models perform better than the Elman model; however, we see no significant difference in performance between GRU and LSTM. RNNs with dropout require more weights to reach the same validation error as networks without dropout. However, the gap between training error and validation error becomes smaller when dropout is applied, reducing over-fitting and improving generalization. Another advantage in using dropout is that it can be applied during prediction to provide confidence limits on the predictions. The confidence limits increase with increasing Dst magnitude: a consequence of the less populated input-target space for events with large Dst values, thereby increasing the uncertainty in the estimates. The best RNNs have test set RMSE of 8.8 nT, bias close to zero, and linear correlation of 0.90.</jats:p