163 research outputs found
DGSAT: Dwarf Galaxy Survey with Amateur Telescopes II. A catalogue of isolated nearby edge-on disk galaxies and the discovery of new low surface brightness systems
The connection between the bulge mass or bulge luminosity in disk galaxies
and the number, spatial and phase space distribution of associated dwarf
galaxies is a discriminator between cosmological simulations related to galaxy
formation in cold dark matter and generalized gravity models. Here, a nearby
sample of isolated Milky Way class edge-on galaxies is introduced, to
facilitate observational campaigns to detect the associated families of dwarf
galaxies at low surface brightness. Three galaxy pairs with at least one of the
targets being edge-on are also introduced. About 60% of the catalogued isolated
galaxies contain bulges of different size, while the remaining objects appear
to be bulge-less. Deep images of NGC 3669 (small bulge, with NGC 3625 at the
edge of the image) and NGC 7814 (prominent bulge), obtained with a 0.4-m
aperture, are also presented, resulting in the discovery of two new dwarf
galaxy candidates, NGC3669-DGSAT-3 and NGC7814-DGSAT-7. Eleven additional low
surface brightness galaxies are identified, previously notified with low
quality measurement flags in the Sloan Digital Sky Survey (SDSS). Integrated
magnitudes, surface brightnesses, effective radii, Sersic indices, axis ratios,
and projected distances to their putative major hosts are displayed. At least
one of the galaxies, NGC3625-DGSAT-4, belongs with a surface brightness of
approximately 26 mag per arcsec^2 and effective radius >1.5 kpc to the class of
ultra-diffuse galaxies (UDGs). NGC3669-DGSAT-3, the galaxy with lowest surface
brightness in our sample, may also be an UDG.Comment: 12 pages including 6 figures, 4 tables, a brief appendix, accepted
for publication in Astronomy & Astrophysics (A&A). Paper slightly modified
after A&A language editing, updating very few references and correcting a
small typo at the start of the Appendi
Galaxies lacking dark matter in the Illustris simulation
IB is supported by an Alexander von Humboldt research fellowship. We thank the DAAD-Ostpartnerschaftsprogramm fĂźr 2018 at the University of Bonn for funding exchange visits between Charles University in Prague and Bonn University.Context. Any viable cosmological model in which galaxies interact predicts the existence of primordial and tidal dwarf galaxies (TDGs). In particular, in the standard model of cosmology (ÎCDM), according to the dual dwarf galaxy theorem, there must exist both primordial dark matter-dominated and dark matter-free TDGs with different radii. Aims. We study the frequency, evolution, and properties of TDGs in a ÎCDM cosmology. Methods. We use the hydrodynamical cosmological Illustris-1 simulation to identify TDG candidates (TDGCs) and study their present-day physical properties. The positions of galaxies in the radius-mass plane, depending on their nonbaryonic content, are compared with observational data and other simulations. We also present movies on the formation of a few galaxies lacking dark matter, confirming their tidal dwarf nature. Tidal dwarf galaxy candidates can however also be formed via other mechanisms, such as from ram-pressure-stripped material or, speculatively, from cold-accreted gas. Results. We find 97 TDGCs with Mstellar > 5 Ă 107Mâ at redshift z = 0, corresponding to a co-moving number density of 2.3 Ă 10-4 h3 cMpc-3. The most massive TDGC has Mtotal = 3.1 Ă 109 Mâ, comparable to that of the Large Magellanic Cloud. Tidal dwarf galaxy candidates are phase-space-correlated, reach high metallicities, and are typically younger than dark matter-rich dwarf galaxies. Conclusions. We report for the first time the verification of the dual dwarf theorem in a self-consistent ÎCDM cosmological simulation. Simulated TDGCs and dark matter-dominated galaxies populate different regions in the radius-mass diagram in disagreement with observations of early-type galaxies. The dark matter-poor galaxies formed in Illustris-1 have comparable radii to observed dwarf galaxies and to TDGs formed in other galaxy-encounter simulations. In Illustris-1, only 0.17 percent of all selected galaxies with Mstellar = 5 Ă 107-109 Mâ are TDGCs or dark matter-poor dwarf galaxies. The occurrence of NGC 1052-DF2-type objects is discussed.Publisher PDFPeer reviewe
A survival analysis of socio-demographic and clinical predictors among hospitalized COVID-19 patients in Southern Iran
Background: This study aimed to evaluate the socio-demographic, clinical, and laboratory risk factors in hospitalized COVID-19 patients during the first 6Â months of the SARS-CoV-2 epidemic. Method: This retrospective hospital-based cross-sectional study included all laboratory-confirmed cases of the COVID-19 virus that were admitted to the Shohadaye-Khalije-Fars Hospital in Bushehr, Iran, from February 22, 2020 to September 21, 2020. The patients' records were reviewed during the hospitalization period. The global COVID-19 clinical platform, i.e., the World Health Organization Rapid Case Report Form was used as the data collection tool. We conducted the survival analysis using the KaplanâMeier and the Stepwise Cox regression analyses. Results: The analysis included 2108 confirmed cases of COVID-19 with a mean age of 47.81Â years (SD 17.78); 56.8% men, 43.2% women and 6.3% (n = 133) deaths. After adjustment, it was found that factors associated with an increased risk of death consisted of chronic kidney disease, intensive care unit admission, cancer, and hemoptysis. The 7-day survival rate was 95.8%, which decreased to 95.1%, 94.0%, and 93.8% on days 14, 21, and 28 of hospitalization, respectively. Discussion and conclusion: Older COVID-19 patients with manifestation of hemoptysis and a past medical history of chronic kidney disease and cancer, should be closely monitored to prevent disease deterioration and death, and also should be admitted to the intensive care unit
Dynamics of conflicts in Wikipedia
In this work we study the dynamical features of editorial wars in Wikipedia
(WP). Based on our previously established algorithm, we build up samples of
controversial and peaceful articles and analyze the temporal characteristics of
the activity in these samples. On short time scales, we show that there is a
clear correspondence between conflict and burstiness of activity patterns, and
that memory effects play an important role in controversies. On long time
scales, we identify three distinct developmental patterns for the overall
behavior of the articles. We are able to distinguish cases eventually leading
to consensus from those cases where a compromise is far from achievable.
Finally, we analyze discussion networks and conclude that edit wars are mainly
fought by few editors only.Comment: Supporting information adde
Noscapine suppresses angiotensin converting enzyme inhibitors-induced cough
Background: Dry cough is a common side-effect of the angiotensin converting enzyme inhibitors (ACEI) and is a major limiting factor of their use. It has been suggested that ACEI cause this side-effect by potentiation of the bradykinin effect. Previous work in our laboratory has shown that noscapine, an antitussive drug, inhibits the effect of bradykinin. Methods: To investigate the effect of noscapine on ACEI-induced cough, 611 hypertensive patients who were being treated with ACEI were evaluated for the incidence of persistent dry cough. Results: A cough had developed in 65 (10.6) patients, two (3.1) of whom also had severe respiratory distress that required hospitalisation and immediate discontinuation of the ACEI. Forty-two (64.6) patients had developed a mild cough and 21 (32.3) patients had developed a moderate to severe cough. The patients with moderate to severe cough received 15 mg of noscapine, orally three times daily, while they continued ACEI. Noscapine effectively resolved the cough in 19 (90) patients within 4-9 days of starting treatment. Conclusion: Noscapine, possibly by inhibition of bradykinin synthesis, eliminates ACEI-induced cough in the majority of patients and allows them to continue with ACEI therapy. ĂŠ 2005 Asian Pacific Society of Nephrology
Mechanobiology in oncology: basic concepts and clinical prospects
The interplay between genetic transformations, biochemical communications, and physical interactions is crucial in cancer progression. Metastasis, a leading cause of cancer-related deaths, involves a series of steps, including invasion, intravasation, circulation survival, and extravasation. Mechanical alterations, such as changes in stiffness and morphology, play a significant role in all stages of cancer initiation and dissemination. Accordingly, a better understanding of cancer mechanobiology can help in the development of novel therapeutic strategies. Targeting the physical properties of tumours and their microenvironment presents opportunities for intervention. Advancements in imaging techniques and lab-on-a-chip systems enable personalized investigations of tumor biomechanics and drug screening. Investigation of the interplay between genetic, biochemical, and mechanical factors, which is of crucial importance in cancer progression, offers insights for personalized medicine and innovative treatment strategies
Consequences of chronic diseases and other limitations associated with old age - A scoping review
Funding Information: This work supported in part by the LTC INTER COST, Evaluation of the Potential for Reducing Health and Social Expenses for Elderly People Using the Smart Environment, through the Ministry of Education, Youth and Sports, Czech Republic, under Project LTC18035; and in part by the project of Excellence, University of Hradec Kralove, FIM, Czech Republic (ID: 2205â2019). First author â Petra Maresova is principle investigator of LTC18035 INTER COST project, from which Petra Maresova, Ondrej Krejcar and Kamil Kuca are funded for all expenses including personal costs. Ehsan Javanmardi is funded from project of Excellence ID: 2205â2019 for personal costs. Sabina Barakovic, Jasmina Barakovic Husic and Signe Tomsone are members of COST ACTION 16226 of which also Petra Maresova and Ondrej Krejcar are paticipants, while this article also ACKnowledge this project CA16226. Funding Information: The authors would like to hereby acknowledge COST Action CA16226 for their networking support. The Indoor Living Space Improvement: Smart Habitat for the Elderly played a role of networking platform for knowledge sharing and interchanging ideas for joint research and publication, what was the base for creating this study. Based on CA16226 project LTC18035 INTER COST was proposed for national funding support of COST ACTION Framework. COST is a funding agency that helps innovation and research networks. Our Action was instrumental in connecting research programmes throughout the EU region. Their contribution has made it possible for scientists to connect with each other and share their ideas and findings. This allows for more research and better innovation. More information can be found at www.cost.eu. The authors would also like to acknowledge the Excellence 2019 internal research project, Faculty of Informatics and Management, University of Hradec Kralove, Czech Republic. Publisher Copyright: Š 2019 The Author(s).Background: The phenomenon of the increasing number of ageing people in the world is arguably the most significant economic, health and social challenge that we face today. Additionally, one of the major epidemiologic trends of current times is the increase in chronic and degenerative diseases. This paper tries to deliver a more up to date overview of chronic diseases and other limitations associated with old age and provide a more detailed outlook on the research that has gone into this field. Methods: First, challenges for seniors, including chronic diseases and other limitations associated with old age, are specified. Second, a review of seniors' needs and concerns is performed. Finally, solutions that can improve seniors' quality of life are discussed. Publications obtained from the following databases are used in this scoping review: Web of Science, PubMed, and Science Direct. Four independent reviewers screened the identified records and selected relevant publications published from 2010 to 2017. A total of 1916 publications were selected. In all, 52 papers were selected based on abstract content. For further processing, 21 full papers were screened." Results: The results indicate disabilities as a major problem associated with seniors' activities of daily living dependence. We founded seven categories of different conditions - psychological problems, difficulties in mobility, poor cognitive function, falls and incidents, wounds and injuries, undernutrition, and communication problems. In order to minimize ageing consequences, some areas require more attention, such as education and training; technological tools; government support and welfare systems; early diagnosis of undernutrition, cognitive impairment, and other diseases; communication solutions; mobility solutions; and social contributions. Conclusions: This scoping review supports the view on chronic diseases in old age as a complex issue. To prevent the consequences of chronic diseases and other limitations associated with old age related problems demands multicomponent interventions. Early recognition of problems leading to disability and activities of daily living (ADL) dependence should be one of essential components of such interventions.publishersversionPeer reviewe
Does the galaxy NGC1052-DF2 falsify Milgromian dynamics?
A great challenge in current physics is to understand whether the observed internal dynamics of galaxies is due to dark matter or to a modification of the law of gravity. Recently, van Dokkum et al. reported that the ultra-diffuse dwarf galaxy NGC1052âDF2 lacks dark matter, and they claimed that this would â paradoxically â be problematic for modified gravity theories such as Milgromian dynamics (MOND). However, NGC1052âDF2 is not isolated, so a valid prediction of its internal dynamics in MOND cannot be made without properly accounting for the external gravitational fields from neighbouring galaxies. Including this external field effect, following Haghi et al., shows that NGC1052âDF2 is consistent with MOND.PostprintPeer reviewe
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