The Challenge of Machine Learning in Space Weather Nowcasting and Forecasting

The numerous recent breakthroughs in machine learning (ML) make imperative to carefully ponder how the scientific community can benefit from a technology that, although not necessarily new, is today living its golden age. This Grand Challenge review paper is focused on the present and future role of machine learning in space weather. The purpose is twofold. On one hand, we will discuss previous works that use ML for space weather forecasting, focusing in particular on the few areas that have seen most activity: the forecasting of geomagnetic indices, of relativistic electrons at geosynchronous orbits, of solar flares occurrence, of coronal mass ejection propagation time, and of solar wind speed. On the other hand, this paper serves as a gentle introduction to the field of machine learning tailored to the space weather community and as a pointer to a number of open challenges that we believe the community should undertake in the next decade. The recurring themes throughout the review are the need to shift our forecasting paradigm to a probabilistic approach focused on the reliable assessment of uncertainties, and the combination of physics-based and machine learning approaches, known as gray-box.Comment: under revie

Large-scale collective motion of RFGC galaxies in curved space-time

We consider large-scale collective motion of flat edge-on spiral galaxies from the Revised Flat Galaxy Catalogue (RFGC) taking into account the curvature of space-time in the Local Universe at the scale 100 Mpc/h. We analyse how the relativistic model of collective motion should be modified to provide the best possible values of parameters, the effects that impact these parameters and ways to mitigate them. Evolution of galactic diameters, selection effects, and difference between isophotal and angular diameter distances are inadequate to explain this impact. At the same time, measurement error in HI line widths and angular diameters can easily provide such an impact. This is illustrated in a toy model, which allows analytical consideration, and then in the full model using Monte Carlo simulations. The resulting velocity field is very close to that provided by the non-relativistic model of motion. The obtained bulk flow velocity is consistent with {\Lambda}CDM cosmology.Comment: 10 pages, 3 figures, 2 table

Eudor-a: a Naturalistic, European Multi-centre Clinical Study of Edor Test in Adult Patients with Primary Depression

Introduction: Previous findings suggested that electrodermal hyporeactivity has a high sensitivity (up to 97%) and high raw specificity (up to 98%) for suicide. Aim: To evaluate prevalence, sensitivity and specificity of electrodermal hyporeactivity for suicide and suicide attempt, with and without death intent and with violent method or not, in adult patients with a primary diagnosis of depression. Methods: At each study site at least 100 patients with a primary diagnosis of depression, also in remission, will be recruited. Depressive symptomatology will be evaluated through the Montgomery-Asberg Depression Scale. Previous suicide attempts will be registered and the death intent of the worst attempt will be rated according to the first eight items of the Beck Suicide Intent Scale. The risk of suicide will be assessed according to rules and traditions at the centre. The EDOR Test (ElectroDermal Orienting Reactivity) will be performed. Two fingers are put on gold electrodes. Through headphones a moderately strong tone is presented now and then during the test. Sensors located within the electrodes are able to register the electrodermal response to those tones, measuring the skin conductance (i.e. electrodermal activity from sweat gland activity). Each patient will be followed up for one year for actions of intentional self-harm that require medical care and for suicide. The death intent will also be rated. Expected results: It is expected that the EDOR test detects a previously unknown neuropsychological dysfunction that is independent of the depressive state and can predict suicidality with a high sensitivity and specificit

Large-scale collective motion of RFGC galaxies

We processed the data about radial velocities and HI linewidths for 1678 flat edge-on spirals from the Revised Flat Galaxy Catalogue. We obtained the parameters of the multipole components of large-scale velocity field of collective non-Hubble galaxy motion as well as the parameters of the generalized Tully-Fisher relationship in the "HI line width - linear diameter" version. All the calculations were performed independently in the framework of three models, where the multipole decomposition of the galaxy velocity field was limited to a dipole, quadrupole and octopole terms respectively. We showed that both the quadrupole and the octopole components are statistically significant. On the basis of the compiled list of peculiar velocities of 1623 galaxies we obtained the estimations of cosmological parameters Omega_m and sigma_8. This estimation is obtained in both graphical form and as a constraint of the value S_8=sigma_8(Omega_m/0.3)^0.35 = 0.91 +/- 0.05.Comment: Accepted for publication in Astrophysics and Space Scienc