142 research outputs found
Evaluation of sensors to monitor the effect of bentonite on the corrosion rate of copper in Olkiluoto-type saline groundwater
Screening of community-dwelling older patients by the emergency medical services : An observational retrospective registry study
Background: Inadequate nutrition, falls, and cognitive impairment are common problems among acutely ill older people and are associated with complicated and prolonged health problems and mortality. Objectives: To assess if the emergency medical services can identify patients with nutritional risk, falls risk, and cognitive impairment by using simple screening tools and to assess the prevalence of risks and rate they are reported to the emergency department. Setting: The study was carried out in Espoo, Finland to patients over the age of 70 requiring non-urgent ambulance transfer to the emergency department. Outcome measures: A set of validated electronic screening tools was used to identify patients at nutritional risk, risk of falling and having cognitive impairment. Main results: A total of 488 (8%) out of 5792 patients were screened. Of the patients 60%, (n = 292) had at least one risk: 17% (n = 81) had nutritional risk, 43% (n = 209) falls risk, and 28% (n = 137) cognitive impairment. Twenty-two (5%) were screened positive in all three categories. The observed risk was reported to the emergency department staff in 59% (n = 173) of the patients. Conclusion: The emergency medical services can be used in preventive health care to identify patients having nutritional risk, falls risk, or cognitive impairment.Peer reviewe
High-resolution spectroscopy of Boyajian's star during optical dimming events
Financial support from the Spanish Ministry of Economy and Competitiveness through projects AYA2014-60833-P, AYA2014-60476-P, and AYA2017-86389-P are gratefully acknowledged. MJMG and JIGH also acknowledge financial support through the Ramón y Cajal fellowship. GMK is supported by the Royal Society as a Royal Society University Research Support Fellow.Boyajian’s star is an apparently normal main-sequence F-type star with a very unusual light curve. The dipping activity of the star, discovered during the Kepler mission, presents deep, asymmetric, and aperiodic events. Here we present high-resolution spectroscopic follow-up during some dimming events recorded post-Kepler observations, from ground-based telescopes. We analyse data from the HERMES, HARPS-N, and FIES spectrographs to characterize the stellar atmosphere and to put some constraints on the hypotheses that have appeared in the literature concerning the occulting elements. The star’s magnetism, if existing, is not extreme. The spots on the surface, if present, would occupy 0.02 per cent of the area, at most. The chromosphere, irrespective of the epoch of observation, is hotter than the values expected from radiative equilibrium, meaning that the star has some degree of activity. We find no clear evidence of the interstellar medium or exocoments being responsible for the dimmings of the light curve. However, we detect at 1–2σ level, a decrease of the radial velocity of the star during the first dip recorded after the Kepler observations. We claim the presence of an optically thick object with likely inclined and high impact parameter orbits that produces the observed Rossiter–McLaughlin effect.Publisher PDFPeer reviewe
SN 2015bn: A DETAILED MULTI-WAVELENGTH VIEW of A NEARBY SUPERLUMINOUS SUPERNOVA
We present observations of SN 2015bn (=PS15ae = CSS141223-113342+004332 = MLS150211-113342+004333), a Type I superluminous supernova (SLSN) at redshift z = 0.1136. As well as being one of the closest SLSNe I yet discovered, it is intrinsically brighter () and in a fainter galaxy () than other SLSNe at . We used this opportunity to collect the most extensive data set for any SLSN I to date, including densely sampled spectroscopy and photometry, from the UV to the NIR, spanning −50 to +250 days from optical maximum. SN 2015bn fades slowly, but exhibits surprising undulations in the light curve on a timescale of 30–50 days, especially in the UV. The spectrum shows extraordinarily slow evolution except for a rapid transformation between +7 and +20–30 days. No narrow emission lines from slow-moving material are observed at any phase. We derive physical properties including the bolometric luminosity, and find slow velocity evolution and non-monotonic temperature and radial evolution. A deep radio limit rules out a healthy off-axis gamma-ray burst, and places constraints on the pre-explosion mass loss. The data can be consistently explained by a M stripped progenitor exploding with erg kinetic energy, forming a magnetar with a spin-down timescale of ~20 days (thus avoiding a gamma-ray burst) that reheats the ejecta and drives ionization fronts. The most likely alternative scenario—interaction with ~20 M of dense, inhomogeneous circumstellar material—can be tested with continuing radio follow-up.S.J.S. acknowledges funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC Grant agreement no [291222] and STFC grants ST/I001123/1 and ST/L000709/1. This work is based (in part) on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile as part of PESSTO, (the Public ESO Spectroscopic Survey for Transient Objects Survey) ESO program 188.D-3003, 191.D-0935. The Pan-STARRS1 Surveys (PS1) have been made possible through contributions of the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation under Grant No. AST-1238877, the University of Maryland, and Eotvos Lorand University (ELTE). Operation of the Pan-STARRS1 telescope is supported by the National Aeronautics and Space Administration under Grant No. NNX12AR65G and Grant No. NNX14AM74G issued through the NEO Observation Program. Based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. A.G.-Y. is supported by the EU/FP7 via ERC grant No. 307260, the Quantum universe I-Core programme by the Israeli Committee for Planning and Budgeting and the ISF; by Minerva and ISF grants; by the Weizmann-UK "making connections" programme; and by the Kimmel and YeS awards. B.D.M. is supported by NSF grant AST-1410950 and the Alfred P. Sloan Foundation. Support for L.G. is provided by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009 awarded to The Millennium Institute of Astrophysics (MAS), and CONICYT through FONDECYT grant 3140566. This work was partly supported by the European Union FP7 programme through ERC grant number 320360. K.M. acknowledges support from the STFC through an Ernest Rutherford Fellowship. A.M. acknowledges funding from CNRS. Development of ASAS-SN has been supported by NSF grant AST-0908816 and CCAPP at the Ohio State University. ASAS-SN is supported by NSF grant AST-1515927, the Center for Cosmology and AstroParticle Physics (CCAPP) at OSU, the Mt. Cuba Astronomical Foundation, George Skestos, and the Robert Martin Ayers Sciences Fund. B.S. is supported by NASA through Hubble Fellowship grant HF-51348.001 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. C.S.K. is supported by NSF grants AST-1515876 and AST-1515927. T.W.-S.H. is supported by the DOE Computational Science Graduate Fellowship, grant number DE-FG02-97ER25308. V.A.V. is supported by a NSF Graduate Research Fellowship. P.S.C. is grateful for support provided by the NSF through the Graduate Research Fellowship Program, grant DGE1144152. P.B. is supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE1144152. D.A.H., C.M., and G.H. are supported by NSF grant 1313484.This is the author accepted manuscript. The final version is available from the Institute of Physics via http://dx.doi.org/10.3847/0004-637X/826/1/3
Primary Black Hole Spin in OJ 287 as Determined by the General Relativity Centenary Flare
OJÂ 287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts that are predictable in a binary black hole model. The model predicted a major optical outburst in 2015 December. We found that the outburst did occur within the expected time range, peaking on 2015 December 5 at magnitude 12.9 in the optical R -band. Based on Swift /XRT satellite measurements and optical polarization data, we find that it included a major thermal component. Its timing provides an accurate estimate for the spin of the primary black hole, ##IMG## [http://ej.iop.org/images/2041-8205/819/2/L37/apjl523055ieqn1.gif] . The present outburst also confirms the established general relativistic properties of the system such as the loss of orbital energy to gravitational radiation at the 2% accuracy level, and it opens up the possibility of testing the black hole no-hair theorem with 10% accuracy during the present decade.Peer reviewe
A Search for QPOs in the Blazar OJ287: Preliminary Results from the 2015/2016 Observing Campaign
We analyse the light curve in the R band of the blazar OJ287, gathered during the 2015/2016 observing season. We did a search for quasi-periodic oscillations (QPOs) using several methods over a wide range of timescales. No statistically significant periods were found in the high-frequency domain both in the ground-based data and in Kepler observations. In the longer-period domain, the Lomb–Scargle periodogram revealed several peaks above the 99% significance level. The longest one—about 95 days—corresponds to the innermost stable circular orbit (ISCO) period of the more massive black hole. The 43-day period could be an alias, or it can be attributed to accretion in the form of a two-armed spiral wave.Peer reviewe
Conformational Transition Pathway in the Inhibitor Binding Process of Human Monoacylglycerol Lipase
Human monoacylglycerol lipase (MGL) catalyzes the hydrolysis of 2-arachidonoylglycerol to arachidonic and glycerol, which plays a pivotal role in the normal biological processes of brain. Co-crystal structure of the MGL in complex with its inhibitor, compound 1, shows that the helix α4 undergoes large-scale conformational changes in response to the compound 1 binding compared to the apo MGL. However, the detailed conformational transition pathway of the helix α4 in the inhibitor binding process of MGL has remained unclear. Here, conventional molecular dynamics (MD) and nudged elastic band (NEB) simulations were performed to explore the conformational transition pathway of the helix α4. Conventional MD simulations unveiled that the compound 1 induced the closed conformation of the active site of MGL, reduced the conformational flexibility of the helix α4, and elicited the large-scale conformational rearrangement of the helix α4, leading to the complete folding of the helix α4. Moreover, NEB simulations revealed that the conformational transition pathway of helix α4 underwent an almost 180° counter-clockwise rotation of the helix α4. Our computational results advance the structural and mechanistic understanding of the inhibitory mechanism
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