The portrait of Malin 2: a case study of a giant low surface brightness galaxy

The low surface brightness disc galaxy Malin2 challenges the standard theory of galaxy evolution by its enormous total mass ~2 10^12 Ms which must have been formed without recent major merger events. The aim of our work is to create a coherent picture of this exotic object by using the new optical multicolor photometric and spectroscopic observations at Apache Point Observatory as well as archival datasets from Gemini and wide-field surveys. We performed the Malin2 mass modelling, estimated the contribution of the host dark halo and found that it had acquired its low central density and the huge isothermal sphere core radius before the disc subsystem was formed. Our spectroscopic data analysis reveals complex kinematics of stars and gas in the very inner region. We measured the oxygen abundance in several clumps and concluded that the gas metallicity decreases from the solar value in the centre to a half of that at 20-30 kpc. We found a small satellite and measured its mass (1/500 of the host galaxy) and gas metallicity. One of the unique properties of Malin2 turned to be the apparent imbalance of ISM: the molecular gas is in excess with respect to the atomic gas for given values of the gas equilibrium turbulent pressure. We explain this imbalance by the presence of a significant portion of the dark gas not observable in CO and the Hi 21 cm lines. We also show that the depletion time of the observed molecular gas traced by CO is nearly the same as in normal galaxies. Our modelling of the UV-to-optical spectral energy distribution favours the exponentially declined SFH over a single-burst scenario. We argue that the massive and rarefied dark halo which had formed before the disc component well describes all the observed properties of Malin2 and there is no need to assume additional catastrophic scenarios proposed previously to explain the origin of giant LSB galaxies. [Abbreviated]Comment: 17 pages, 10 figures, accepted for publication in MNRA

Magnetic fields near the peripheries of galactic discs

Magnetic fields are observed beyond the peripheries of optically detected galactic discs, while numerical models of their origin and the typical magnitudes are still absent. Previously, studies of galactic dynamo have avoided considering the peripheries of galactic discs because of the very limited (though gradually growing) knowledge about the local properties of the interstellar medium. Here we investigate the possibility that magnetic fields can be generated in the outskirts of discs, taking the Milky Way as an example. We consider a simple evolving galactic dynamo model in the "no-z" formulation, applicable to peripheral regions of galaxies, for various assumptions about the radial and vertical profiles of the ionized gas disc. The magnetic field may grow as galaxies evolve, even in the more remote parts of the galactic disc, out to radii of 15 to 30 kpc, becoming substantial after times of about 10 Gyr. This result depends weakly on the adopted distributions of the half thickness and surface density of the ionized gas component. The model is robust to changes in the amplitude of the initial field and the position of its maximum strength. The magnetic field in the remote parts of the galactic disc could be generated in situ from a seed field by local dynamo action. Another possibility is field production in the central regions of a galaxy, followed by transport to the disc's periphery by the joint action of the dynamo and turbulent diffusivity. Our results demonstrate the possibilities for the appearance and strengthening of magnetic fields at the peripheries of disc galaxies and emphasize the need for observational tests with new and anticipated radio telescopes (LOFAR, MWA, and SKA).Comment: 8 pages, 5 figure

Inferring Student Engagement in Collaborative Problem Solving from Visual Cues

Automatic analysis of students' collaborative interactions in physical settings is an emerging problem with a wide range of applications in education. However, this problem has been proven to be challenging due to the complex, interdependent and dynamic nature of student interactions in real-world contexts. In this paper, we propose a novel framework for the classification of student engagement in open-ended, face-to-face collaborative problem-solving (CPS) tasks purely from video data. Our framework i) estimates body pose from the recordings of student interactions; ii) combines face recognition with a Bayesian model to identify and track students with a high accuracy; and iii) classifies student engagement leveraging a Team Long Short-Term Memory (Team LSTM) neural network model. This novel approach allows the LSTMs to capture dependencies among individual students in their collaborative interactions. Our results show that the Team LSTM significantly improves the performance as compared to the baseline method that takes individual student trajectories into account independently

Diagnostic Games, a Tool for Clinical Experience Formalization in Interactive “Physician – IT-specialist ” Framework

The specific characteristics of data processing in clinical decision problems require special approaches. This was the insight that made Izrail Gelfand and his colleagues look for new methods of formalization that would allow to discover the intrinsic structures in clinical data. A special technique for collaborative work of IT specialists and physicians named “diagnostic games ” (DG) was developed for this purpose. This approach including the DG and related ideas of an “adequate language ” and “structural units ” is presented in this paper. The preliminary setting of clinical decision problem of surgical timing in patients with ruptured subarachnoid aneurysm is introduced as a subject for further formalization

EVALUATION OF SEWAGE WITHIN MAKHACHKALA BY CHEMICAL PARAMETERS

Abstract. Theme. Assessment of the quality of wastewater within Makhachkala by chemical parameters.Location. Makhachkala, Dagestan, Russia.The aim of the study is to determine the chemical quality of sewage water polluting the Caspian Sea within the city of Makhachkala.Method. Object of study is the sample of wastewater sampled 10–11 January 2012 within the city of Makhachkala. Sampling of wastewater and chemical analysis was carried out in accordance with the International Organization for Standardization. Quality test samples evaluated in terms of water pollution index and coefficient calculation integrated pollution.Results. Using certified measurement techniques in 9 samples of wastewater identified 26 normalized parameters. Found that wastewater selected in two paragraphs refer to quality very dirty, 7 points extremely dirty; in all samples of wastewater content from 6 to 10 standardized components exceeds the MCL and the coefficient of the complex water pollution 7 samples belong to category II and contamination of sample 2 to Category III contamination.Main conclusion. The data obtained can be considered as the primary material for further chemical monitoring the quality of wastewater into the Caspian Sea within the administrative boundaries of the city of Makhachkala

Atomic and Molecular Gas Components in Spiral Galaxies of the Virgo Cluster

Based on two models, we investigate the molecular-to-atomic gas ratio in Virgo cluster galaxies in comparison with field galaxies. We show that the enhanced metallicity for cluster members and the ram pressure stripping of atomic gas from the disk periphery cannot fully explain the observed gas component ratios. The additional environmental factors affecting the interstellar medium and leading to an increase in the molecular gas fraction should be taken into account for cluster galaxies.Comment: 11 pages, 4 figure

FEATURES OF INDICATORS OF SITUATIONAL AND PERSONAL ANXIETY IN PATIENTS WITH METABOLIC SYNDROME

The purpose of the study. To study the influence of various metabolic syndrome clusters on the severity of situational and personal anxiety. Materials and methods. The study included 136 patients, including 60 with metabolic syndrome. Metabolic syndrome was diagnosed based on the criteria of clinical recommendations of the All-Russian Scientific Society of Cardiology in 2009. The severity of personal and situational anxiety was assessed using the scale of self-assessment of the level of anxiety by Ch.D. Spielberger modified by Yu.L. Khanina. Results. It was established that in the examined groups of men, the median scores of both personal and situational anxieties corresponded to a moderate level. The most common variant of metabolic syndrome among men with high and moderate levels of situational and personal anxiety was its three-component combination. Among men with moderate and high levels of situational anxiety, there were statistically significantly more people with 5 or more metabolic syndrome components compared to patients with low levels. Conclusion. The combination of central obesity, arterial hypertension, and lipid disorders characterized by high levels of low-density lipoprotein was the most common cluster of MS among men with high and moderate levels of situational and personal anxiety