58 research outputs found

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

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    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

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

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    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

    SMEs in a low carbon economy: final report for BERR enterprise directorate.

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    This report reviews the established evidence and thinking around the challenges and opportunities that will affect UK small and medium-sized enterprises (SMEs) in the transition to a low carbon economy. The serious threat of global climate change is primarily caused by the burning of fossil fuels and land-use change and few now dispute that there is a need for urgent collective action to achieve a transition to a low carbon and more resource efficient economy. Although little has been written specifically on SMEs in a low carbon economy, a considerable body of relevant academic and policy literature has been identified

    EVALUATION OF SEWAGE WITHIN MAKHACHKALA BY CHEMICAL PARAMETERS

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    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

    Pathophysiological disorders in iron metabolism in the development of obesity and metabolic syndrome

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    Obesity and metabolic syndrome are one of the major public health problems in the 21st century due to their prevalence. Nonalcoholic fatty liver disease, dyslipidemia, type 2 diabetes mellitus, arterial hypertension, chronic inflammation and anemia are non-communicable diseases accompanying obesity. With obesity, there is a violation of iron metabolism, iron deficiency, which further contributes to the  development of  metabolic disorders. Iron is the  second most abundant metal on Earth, and its bioavailability is reduced due to the formation of insoluble oxides, while iron deficiency is the most common nutritional disorder. Iron metabolism in the body is associated with the formation of reactive oxygen species involved in lipid peroxidation processes. Iron metabolism in the human body is regulated at all levels; dysregulation of any stage of metabolism can lead to iron deficiency and the development of anemia associated with obesity. This review article summarizes data on molecular and cellular abnormalities in iron metabolism in obesity and metabolic syndrome. The aim of our study was to study, according to the literature, pathophysiological disorders in iron metabolism in the development of obesity and metabolic syndrome. In the future, more research is required to study iron metabolism in obesity with the aim of their preventive and therapeutic effects. The role of oxidative stress in impaired iron metabolism in obesity has not been fully studied, while iron deficiency enhances lipid peroxidation processes in antioxidant deficiency. Under these conditions, oxidative stress can damage cells and destroy red blood cells. The question arises whether the restoration of iron homeostasis in obesity can improve metabolic, inflammatory disorders and reduce the manifestation of oxidative stress, becoming a new innovative approach to the treatment of concomitant metabolic diseases associated with obesity

    Antarctic bdelloid rotifers: diversity, endemism and evolution

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    Antarctica is an isolated continent whose conditions challenge the survival of living organisms. High levels of endemism are now known in many Antarctic organisms, including algae, tardigrades, nematodes and microarthropods. Bdelloid rotifers are a key, widespread and abundant group of Antarctic microscopic invertebrates. However, their diversity, regional distribution and endemism have received little attention until recently. We provide the first authoritative review on Antarctic Bdelloidea, based on published data and new collections. Our analysis reveals the extreme levels of bdelloid endemism in Antarctica. Sixty-six bdelloid morphospecies are now confirmed from the continent, and 83–91 putative species are identified using molecular approaches (depending on the delimitation method used). Twelve previously unknown species are described based on both morphology and molecular analyses. Molecular analyses indicate that only two putative species found in Antarctica proved to be truly cosmopolitan. The level of endemism based on the available data set (95%) is higher than that in any other continent, with many bdelloid species occurring only in maritime or continental Antarctica. These findings are consistent with the long-term presence of Bdelloidea in Antarctica, with their considerable isolation facilitating intraregional radiation, providing further evidence that does not support the microbial global ubiquity hypothesis that “everything is everywhere.

    H-alpha Survey of the Local Volume: Isolated Southern Galaxies

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    We present our H-alpha observations of 11 isolated southern galaxies: SDIG, PGC 51659, E 222-010, E 272-025, E 137-018, IC 4662, Sag DIG, IC 5052, IC 5152, UGCA 438, and E149-003, with distances from 1 to 7 Mpc. We have determined the total H-alpha fluxes from these galaxies. The star formation rates in these galaxies range from 10^{-1} (IC 4662) to 10^{-4}_{\odot}/yr (SDIG) and the gas depletion time at the observed star formation rates lies within the range from 1/6 to 24 Hubble times H_0^{-1} .Comment: 9 pages, 3 figure

    ADDRESSING ENVIRONMENTAL CHALLENGES UNDER COMPREHENSIVE UTILIZATION OF GEOTHERMAL SALINE WATER RESOURCES IN THE NORTHERN DAGESTAN

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    Aim. The aim of the study is to develop technologies for processing geothermal brine produced with the extraction of oil as well as to solve environmental problems in the region.Methods. In order to determine the chemical composition and radioactivity of the geothermal water and solid samples, we used atomic absorption and gamma spectrometry. Evaluation of the effectiveness of the technology was made on the basis of experimental studies.Results. In the geothermal water, eight radionuclides were recognized and quantified with the activity of 87 ± 5 Bq / dm3. For the processing of this water to produce lithium carbonate and other components we propose a technological scheme, which provides a step of water purification from radio-nuclides. As a result of aeration and alkalinization, we can observe deactivation and purification of the geothermal water from mechanical impurities, iron ions, hydrogen carbonates and organic substances. Water treatment allows recovering lithium carbonate, magnesite caustic powder and salt from geothermal water. The mother liquors produced during manufacturing operations meet the requirements for the water suitable for waterflooding of oil reservoirs and can be injected for maintaining the reservoir pressure of the deposits.Conclusion. The implementation of the proposed processing technology of mineralized geothermal water produced with the extraction of oil in the Northern Dagestan will contribute to extend the life of the oil fields and improve the environmental problems. It will also allow import substitution in Russia for lithium carbonate and edible salt

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

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    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
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