Optical and near-infrared photometry, optical spectroscopy, and soft X-ray and UV monitoring of the changing-look active galactic nucleus NGC 2617 show that it continues to have the appearance of a ...type-1 Seyfert galaxy. An optical light curve for 2010–2016 indicates that the change of type probably occurred between 2010 October and 2012 February and was not related to the brightening in 2013. In 2016, NGC 2617 brightened again to a level of activity close to that in 2013 April. We find variations in all passbands and in both the intensities and profiles of the broad Balmer lines. A new displaced emission peak has appeared in Hβ. X-ray variations are well correlated with UV–optical variability and possibly lead by ∼2–3 d. The K band lags the J band by about 21.5 ± 2.5 d and lags the combined B + J filters by ∼25 d. J lags B by about 3 d. This could be because J-band variability arises from the outer part of the accretion disc, while K-band variability comes from thermal re-emission by dust. We propose that spectral-type changes are a result of increasing central luminosity causing sublimation of the innermost dust in the hollow bi-conical outflow. We briefly discuss various other possible reasons that might explain the dramatic changes in NGC 2617.
THE CHANGING LOOK AGNS MONITORING PROJECT Oknyanskij, V. L.; Huseynov, N. A.; Lipunov, V. M. ...
Odessa astronomical publications,
12/2016, Volume:
29
Journal Article
Peer reviewed
Open access
The Changing Look AGNs (CL AGNs) are objects which undergo dramatic variability of the emission line profiles and classification type of which can move from one spectral class to another within very ...short time interval (from days to years). We start the project of spectral and photometric multiwavelength (from IR to X-ray) monitoring which include the selected set of AGNs also known as the CL AGNs. We are going to use 2-m Zeiss telescope (ShAO) for optical spectral observations, 2.5-m telescope of SAI for IR JHK photometry and spectrophotometery, small telescopes Zeiss-600, AZT-5 for BVRI photometry. We are also going to search for the new CL AGNs using the MASTER data. Furthermore, we can get historical light curves for the known and the new discovered objects using the MASTER opportunities. We are planning to apply for X-ray and UV observations of some CL AGNs with the SWIFT. We present some results of such monitoring of the transient object NGC2617. The main goal of the project is to investigate the possibilities for the repeating cases of the strong changes of spectral type at the CL AGNs. Investigation of such type of objects can be very informative for understanding the nature of these fast variations as well as physics of the AGNs.
Healthcare-associated infections (HAIs) caused by multidrug-resistant organisms (MDROs) have a high impact in terms of morbidity, mortality, and costs.
To estimate the prevalence and incidence of ...HAIs, and to describe phenotypic and genotypic features of antimicrobial resistance in responsible pathogens in Ukraine.
Prospective multicentre surveillance was conducted from January 2019 to December 2021 in 17 regional hospitals of Ukraine. Definitions of HAIs were adapted from the Centers for Disease Control and Prevention's National Healthcare Safety Network.
Among 37,968 patients, 6218 (16.4%) HAIs were observed. Of all HAI cases, 14.8% were detected after hospital discharge. The most frequently reported HAI types were pneumonia (24.4%), urinary tract infections (19.8%), surgical site infections (15.3%), and bloodstream infections (11.2%). Of all HAIs, 11.9% were defined as part of an outbreak. Death during hospitalization was reported in 12.6% of HAI cases. In total, 85.1% isolates from patients were found to be MDROs. Meticillin resistance was found in 41.2% of S. aureus (MRSA) isolates, and vancomycin resistance was found in 11.8% of enterococci. Antimicrobial resistance to third-generation cephalosporins was detected in 48.4% of all Enterobacterales. Antimicrobial resistance to carbapenems was detected in 71.3% of all non-fermentative Gram-negative bacteria. Of the all isolates tested, 25.1% were found to be multidrug-resistant (MDR).
This study found a high prevalence of HAIs; those caused by MDROs varied widely depending on the bacterial species, antimicrobial group, and geographical region of Ukraine. MDROs were one of the main causes of HAI-associated deaths.
The increasing emergence and spread of multi-drug-resistant organisms (MDROs) in hospitals is a public health problem and continues to challenge infection control and hospital epidemiology practice ...worldwide.
The aim of this study was to characterize the epidemiology of transmission of MDROs via healthcare workers (HCWs) and the environment in the hospital wards/patient rooms.
A multi-centre prospective observational study was conducted in 17 hospitals in Ukraine. Species identification was performed with standard microbial methods. β-Lactamase genes were investigated by polymerase chain reaction. Pulsed-field gel electrophoresis (PFGE) was used to determine the genetic similarity between isolates.
Among 51,656 isolates, 19.5% were MDROs. The proportions of MDROs among isolates from patients with healthcare-associated infections, environmental surfaces and HCWs (hands, gown/gloves) were 29.2%, 16.3% and 24.2%, respectively. In 51.9% of the tested isolates, identical MDROs were found in clinical isolates, environmental samples and HCWs' hands. Meticillin resistance was found in 32.4% of Staphylococcus aureus (MRSA) isolates, and vancomycin resistance was found in 28.9% of enterococci (VRE). Resistance to third-generation cephalosporins was detected in 48.4% of Enterobacterales, and carbapenem resistance in 19.1%. Overall, 37.4% of MDROs had broad-spectrum β-lactamase genes, including extended-spectrum β-lactamase (35.8%), OXA-type (29.7%), AmpC-type (25.1%), KPC-type (25.7%) and metallo-β-lactamases, including IMP-type (5.7%), VIM-type (31.7%) and NDM-1 (21.3%).
In Ukrainian hospitals the prevalence of healthcare-associated infections caused by MDROs continues to increase, while infection control gaps in healthcare settings facilitate their transmission between patients.
Nonlinear absorption in GaS–GaSe heterostructures under the action of a Nd:YAG laser with built-in generators of the 2nd and 3rd harmonics, designed to generate radiation with wavelengths of 1064, ...532, and 335 nm, is experimentally studied. It is shown that the appearance of characteristic radiation in the luminescence spectra and the behavior of the dependence of luminescence on the excitation intensity indicate the presence of two- and three-photon absorption processes in GaS-GaSe heterostructures.
The article contains an introduction, general research objectives are indicated, a comprehensive solution for evaluating raw materials for industrial processing for various types of food products is ...presented, 18 promising table grape varieties are studied as well as their yield and commercial quality, the percentage of non-standard products is determined, and mathematical processing of data is carried out. Correlation and regression analysis showed that the relationship between yield and yield of marketable grapes is reliable and strong, and the form of correlation is direct (r = 0.99). The indicated dependence is described by the equation y = 0.937x-1.2139. The regression coefficient by x = 0.937 shows in which direction and how the function (y) changes on average when the argument (x) changes. Using the obtained equations, it is possible to construct a theoretical line of regression, according to which it is possible to predict the value of marketable grapes from yield. An increase in the yield of grapes for every 10 centners per hectare leads to an increase in the yield of marketable grapes by 9.37 %.
Charge transport in (TlGaSe
2
)
1 –
x
(TlInS
2
)
x
solid solutions in the frequency range of 20–10
6
Hz before and after γ irradiation is studied using impedance-spectroscopy methods. The relaxation ...character of the permittivity dispersion and the nature of the dielectric loss are established. The frequency dependence of the dissipation factor tanδ in the crystals of the (TlGaSe
2
)
1 –
x
(TlInS
2
)
x
solid solutions is caused not only by relaxation polarization, but also by reach-through conductivity. The relaxation times are found to be τ = 10
–3
s. It is determined that, in the frequency range of 10
5
–5 × 10
5
Hz, the electrical conductivity obeys the regularity σ ~
f
S
(0.1 ≤
S
≤ 1.0), which is indicative of the conductivity over localized states. It is shown that a further increase in the frequency leads to an increase in the ionic conductivity and transition of the system to the superionic state.
The effect of γ-radiation on the optical properties of layered TlGaSe
2
and TlInS
2
crystals has been studied within a wavelength range of 400–1100 nm at 300 K. By means of analysis of optical ...absorption spectra, the energies of direct and indirect optical interbend transitions before and after γ-irradiation have been determined. It has been shown that the energies of direct and indirect nonforbidden optical transitions grow with accumulation of γ-radiation dose within 0–25 Мrad in TlGaSe
2
and TlInS
2
single crystals from
E
gd
= 2.06 eV and
E
gi
= 1.90 eV at
D
= 0 Мrad to
E
gd
= 2.11 eV and
E
gi
= 1.98 eV at
D
= 25 Мrad for TlGaSe
2
crystals and from
E
gd
= 2.32 eV and
E
gi
= 2.27 eV at
D
= 0 Мrad to
E
gd
= 2.35 eV and
E
gi
= 2.32 eV at
D
= 25 Мrad for TlInS
2
crystals. A decrease in the transmission coefficient at doses from 0 to 5 Mrad with a further increase in the transmission coefficient at a radiation dose of
D
= 25 Мrad is observed.
Conductivity inversion in thin
n
-InSe films under intense pulsed laser irradiation was obser. A
p
–
n
structure based on indium selenide formed between irradiated and nonirradiated regions of a ...thin-film sample. It was confirmed by EDAX analysis that the composition of the sample remained the same after irradiation. The conductivity inversion is attributed to a change in the dynamics of lattice defects under heating.
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