101 research outputs found
Updated radio relation for Galactic supernova remnants
We present updated empirical radio surface-brightness-to-diameter
() relation for supernova remnants (SNRs) in our Galaxy. Our original
calibration sample of Galactic SNRs with independently determined distances
(Pavlovic et al. 2013, hereafter Paper I) is reconsidered and updated with data
which became available in the past two years. The orthogonal fitting procedure
and probability-density-function-based (PDF) method are applied to the
calibration sample in the plane. Orthogonal regression
keeps and relations invariant. Our previous Monte Carlo
simulations verified that the slopes of the empirical relation
should be determined by using orthogonal regression. Updated calibration sample
contains 65 shell SNRs. 6 new Galactic SNRs are added to the sample from Paper
I, one is omitted and distances are changed for 10 SNRs. The slope derived here
is slightly steeper () than slope in Paper I
(). The PDF method relies on data points density maps which
can provide more reliable calibrations that preserve more information contained
in the calibration sample. We estimate distances to five new faint Galactic
SNRs discovered for the first time by Canadian Galactic Plane Survey and
obtained distances of 2.3, 4.0, 1.3, 2.9 and 4.7 kiloparsecs for G108.5+11.0,
G128.5+2.6, G149.5+3.2, G150.8+3.8 and G160.11.1, respectively. The updated
empirical relation is used to estimate distances of 160 shell Galactic SNRs and
new results change their distance scales up to 15 per cent, compared to results
from Paper I. The PDF calculation can provide even few times higher or lower
values in comparison with orthogonal fit, as it uses totally different
approach. However, in average, this difference is 32, 24 and 18 per cent for
mode, median and mean distances.Comment: 17 pages, 3 figures, Accepted for publication in Serbian Astronomical
Journa
Revealing the nature of central emission nebulae in the dwarf galaxy NGC 185
In this paper we present new optical observations of the galaxy NGC 185
intended to reveal the status of supernova remnants (SNRs) in this dwarf
companion of the Andromeda galaxy. Previously, it was reported that this galaxy
hosts one SNR. Our deep photometric study with the 2m telescope at Rozhen
National Astronomical Observatory using narrow-band H and [SII] filters
revealed complex structure of the interstellar medium in the center of the
galaxy. To confirm the classification and to study the kinematics of the
detected nebulae, we carried out spectroscopic observations using the SCORPIO
multi-mode spectrograph at the 6m telescope at the Special Astrophysical
Observatory of the Russian Academy of Science, both in low- and high-resolution
modes. We also searched the archival X-ray and radio data for counterparts of
the candidate SNRs identified by our optical observations. Our observations
imply the presence of one more SNR, one possible HII region previously
cataloged as part of an SNR, and the presence of an additional source of shock
ionization in one low-brightness PN. We detected enhanced [SII]/H_alpha and
[NII]/H_alpha line ratios, as well as relatively high (up to 90 km s)
expansion velocities of the two observed nebulae, motivating their
classification as SNRs (with diameters of 45 pc and 50 pc), confirmed by both
photometric and spectral observations. The estimated electron density of
emission nebulae is 30 - 200 cm. Archival XMM-Newton observations
indicate the presence of an extended, low-brightness, soft source in projection
of one of the optical SNRs, whereas the archival VLA radio image shows weak,
unresolved emission in the center of NGC 185.Comment: 15 pages, 14 figures, accepted for publication in A&
Associations of age with reward delay discounting and response inhibition in adolescents with bipolar disorders
Bipolar disordersā (BD) onset before age 18 is a potential marker for a more severe illness course. Adolescence is also a period of significant normative maturation of inhibitory control and reward-relevant decision-making processes, such as decreased delay discounting (i.e., decreased preference for smaller, immediate versus larger, delayed rewards). Adults with BD exhibit elevated delay discounting rates. Very little is known about developmental changes in delay discounting in adolescents with BD, or about associations between inhibitory control and delay discounting in BD. The present study addresses these questions
Outbreak of West Nile virus infection among humans in Serbia, August to October 2012
We describe the first reported outbreak of West Nile virus (WNV) infection in humans in Serbia in August to October 2012 and examine the association of various variables with encephalitis and fatal outcome. Enzyme-linked immunosorbent assay (ELISA) was used for detection of WNV-specific IgM and IgG antibodies in sera and cerebrospinal fluid. A total of 58 patients (mean age: 61 years; standard deviation: 15) were analysed: 44 were from Belgrade and its suburbs; 52 had neuroinvasive disease, of whom 8 had meningitis, while 44 had encephalitis. Acute flaccid paralysis developed in 13 of the patients with encephalitis. Age over 60 years and immunosuppression (including diabetes) were independently associated with the development of encephalitis in a multivariate analysis: odds ratio (OR): 44.8 (95% confidence interval (CI): 4.93-408.59); p=0.001 (age over 60 years); OR: 10.76 (95% CI: 1.06-109.65); p=0.045 (immunosuppression including diabetes). Respiratory failure requiring mechanical ventilation developed in 13 patients with encephalitis. A total of 35 patients had completely recovered by the time they were discharged; nine patients died. The presence of acute flaccid paralysis, consciousness impairment, respiratory failure and immunosuppression (without diabetes) were found to be associated with death in hospital in a univariate analysis (p lt 0.001, p=0.007, p lt 0.001 and p=0.010, respectively)
Multi-frequency study of a new Fe-rich supernova remnant in the Large Magellanic Cloud, MCSNR J0508-6902
We present a detailed radio, X-ray and optical study of a newly discovered
Large Magellanic Cloud (LMC) supernova remnant (SNR) which we denote MCSNR
J0508-6902. Observations from the Australian Telescope Compact Array (ATCA) and
the X-ray observatory are complemented by deep H
images and Anglo Australian Telescope AAOmega spectroscopic data to study the
SNR shell and its shock-ionisation. Archival data at other wavelengths are also
examined. The remnant follows a filled-in shell type morphology in the
radio-continuum and has a size of 74 pc 57 pc at the LMC
distance. The X-ray emission exhibits a faint soft shell morphology with
Fe-rich gas in its interior indicative of a Type Ia origin. The remnant
appears to be mostly dissipated at higher radio-continuum frequencies leaving
only the south-eastern limb fully detectable while in the optical it is the
western side of the SNR shell that is clearly detected. The best-fit
temperature to the shell X-ray emission ( keV) is
consistent with other large LMC SNRs. We determined an O/Fe ratio of and
an Fe mass of 0.5-1.8 in the interior of the remnant, both of which
are consistent with the Type Ia scenario. We find an equipartition magnetic
field for the remnant of 28 G, a value typical of older SNRs and
consistent with other analyses which also infer an older remnant
Optical Spectra of Radio Planetary Nebulae in the Small Magellanic Cloud
We present preliminary results from spectral observations of four candidate
radio sources co-identified with known planetary nebulae (PNe) in the Small
Magellanic Cloud (SMC). These were made using the Radcliffe 1.9-meter telescope
in Sutherland, South Africa. These radio PNe were originally found in Australia
Telescope Compact Array (ATCA) surveys of the SMC at 1.42 and 2.37 GHz, and
were further confirmed by new high resolution ATCA images at 6 and 3 cm
(4"/2"). Optical PNe and radio candidates are within 2" and may represent a
subpopulation of selected radio bright objects. Nebular ionized masses of these
objects may be 2.6 MSol or greater, supporting the existence of PNe progenitor
central stars with masses up to 8 MSol.Comment: 6 pages 8 figures, to be published in Serbian Astronomical Journa
Karakteristike Trihineloze kod ljudi na teritoriji Vojvodine u periodu 2002-2011
Current data on the incidence of the disease and abundant research strongly indicate that Trichinellosis has been widely present throughout past few decades, and is endemic in some regions of Serbia. Unfavourable epidemiological situation is due to high prevalence of infection sources and inadequate control of home-processed meat and meat products. The aim of this article was to describe the features of recorded trichinellosis outbreaks in Vojvodina according to gender structure of patients, based on the records obtained from the Institute for Public Health of Vojvodina in Novi Sad. Analysis of the number of diseased and hospitalized patients from the territory of Autonomous Province of Vojvodina in the ten-year period (2002-2011) revealed a total number of 983 patients with trichinellosis. The highest incidence of the disease was recorded in 2005, when 277 people were diagnosed with trichinellosis. Unfavourable epidemiological situation was observed also in 2002, with 275 affected patients. It is to be emphasized that in 2002 and 2005 three lethal outcomes were recorded, as a direct consequence of intensive migration and abundant invasion of T. spiralis larvae. The lowest incidence of the disease was recorded in 2010, that is, only 10 diseased patients. Primary prevention implying appropriate animal husbandry is the crucial point for the disease control, while thorough and systematic inspection of meat of home-produced pigs, wild boars, horses and other animals that can be a potential source of infection. The major risk factor for the occurrence of the disease is consuming raw or undercooked meat that was not subjected to standard examination methods, i.e. examining the skeletal striated musculature from predilection sites by trichinoscopy or artificial digestion.Na osnovu aktuelnih podataka o pojavi ovog oboljenja i brojnih nauÄnih istraživanja, uoÄava se da je Trihineloza veÄ nekoliko decenija naÅ”a stvarnost, a teritorija Srbije epidemioloÅ”ko podruÄje. Nepovoljna epidemioloÅ”ka situacija je posledica raÅ”irenosti žariÅ”ta trihineloze i nesprovoÄenja validne kontrole infestiranosti mesa i mesnih produkata proizvedenih u domaÄinstvima. Cilj ovog rada je da predstavi karakteristike registrovanih epidemija trihineloze u Vojvodini, po starosnoj i polnoj strukturi obolelih osoba na osnovu podataka Instituta za javno zdravlje Vojvodine u Novom Sadu. Analizom broja obolelih i hospitalizovanih ljudi na teritoriji Autonomne pokrajine Vojvodine u ispitivanom vremenskom intervalu od deset godina (od 2002. do 2011. godine), ustanovljeno je da je obolelo ukupno 983 osoba. PosmatrajuÄi svaku godinu posebno ustanovljava se da je najveÄi broj obolelih ljudi od trihineloze bio 2005. godine. U toj godini obolelo je 277 lica, uz to, epidemioloÅ”ka situacija je bila vrlo nepovoljna u 2002. godini kada je obolelo 275 ljudi. Važno je napomenuti, da je u ove dve godine (2002. i 2005. godina) bilo i tri smrtna ishoda koja su nastali kao direktna posledica migracije i velikog naseljavanja infektivnih larvi T. spiralis u organizmu obolelih. Sa druge strane, u analiziranom desetogodiÅ”njem periodu najmanji broj obolelih ljudi (10) zabeležen je 2010. godine. U kontroli bolesti najvažnija je primarna prevencija koja podrazumeva odgovarajuÄe držanje životinja, a osnovna mera za spreÄavanje obolevanja ljudi je pregled mesa domaÄih svinja, divljih svinja, konja, ali i mesa drugih životinja koje mogu biti izvor infekcije. Glavni rizik za pojavu bolesti je konzumiranje sirovog i nedovoljno termiÄki obraÄenog mesa ukoliko uzorci popreÄnoprugaste muskulature sa predilekcionih mesta nisu pregledani standardnim metodama, trihineloskopijom i veÅ”taÄkom digestijom
Murchison Widefield Array and XMM-Newton observations of the Galactic supernova remnant G5.9+3.1
In this paper we discuss the radio continuum and X-ray properties of the
so-far poorly studied Galactic supernova remnant (SNR) G5.9+3.1. We present the
radio spectral energy distribution (SED) of the Galactic SNR G5.9+3.1 obtained
with the Murchison Widefield Array (MWA). Combining these new observations with
the surveys at other radio continuum frequencies, we discuss the integrated
radio continuum spectrum of this particular remnant. We have also analyzed an
archival XMM-Newton observation, which represents the first detection of X-ray
emission from this remnant. The SNR SED is very well explained by a simple
power-law relation. The synchrotron radio spectral index of G5.9+3.1, is
estimated to be 0.420.03 and the integrated flux density at 1GHz to be
around 2.7Jy. Furthermore, we propose that the identified point radio source,
located centrally inside the SNR shell, is most probably a compact remnant of
the supernova explosion. The shell-like X-ray morphology of G5.9+3.1 as
revealed by XMM-Newton broadly matches the spatial distribution of the radio
emission, where the radio-bright eastern and western rims are also readily
detected in the X-ray while the radio-weak northern and southern rims are weak
or absent in the X-ray. Extracted MOS1+MOS2+PN spectra from the whole SNR as
well as the north, east, and west rims of the SNR are fit successfully with an
optically thin thermal plasma model in collisional ionization equilibrium with
a column density N_H~0.80x cm and fitted temperatures spanning
the range kT~0.14-0.23keV for all of the regions. The derived electron number
densities n_e for the whole SNR and the rims are also roughly comparable
(ranging from ~ cm to ~ cm, where f
is the volume filling factor). We also estimate the swept-up mass of the X-ray
emitting plasma associated with G5.9+3.1 to be ~.Comment: Accepted for publication in A&
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