115 research outputs found
Obturacyjny bezdech senny — dlaczego należy go rozpoznawać i leczyć w grupie kierowców?
Wypadki drogowe stanowią ważną przyczynę zgonów i niepełnosprawności, szczególnie u osób aktywnych zawodowo. Grupą kierowców w większym stopniu narażoną na tego rodzaju wypadki są zawodowi kierowcy, a zwłaszcza osoby z obturacyjnym bezdechem sennym (OSA), który stanowi dodatkowo czynnik ryzyka rozwoju wielu schorzeń kardiologicznych (m.in. nadciśnienia tętniczego, udaru mózgu, zaburzeń rytmu czy zawału serca). Ze względów bezpieczeństwa jest niezwykle istotne, aby choroba ta była wcześnie zdiagnozowana, właściwie leczona i kontrolowana. Z tego powodu Grupa Robocza ds. OSA działająca pod auspicjami Komisji Europejskiej, a wcześniej również amerykańska Federal Motor Carrier Safety Administration, American Thoracic Society oraz kanadyjskie Canadian Thoracic Society — Canadian Sleep Society, przygotowały zalecenia dotyczące wydawania oraz recertyfikacji praw jazdy u zawodowych kierowców z OSA, a także warunków natychmiastowego zawieszenia prawa jazdy w tej grupie kierowców. Ze względu na fakt, że częstą, choć potencjalnie niedoszacowaną, przyczyną wypadków drogowych jest zaśnięcie za kierownicą, są prowadzone badania w celu identyfikacji pacjentów cechujących się szczególnie zwiększonym ryzykiem takiego epizodu. W artykule przedstawiono rolę OSA jako czynnika ryzyka nie tylko incydentów sercowo-naczyniowych, ale także wypadków drogowych, możliwości wyodrębnienia grup pacjentów narażonych na taki wypadek (szczególnie będący skutkiem zaśnięcia za kierownicą) oraz zalecenia towarzystw naukowych i agend rządowych dotyczące postępowania w tej grupie chorych
Systematic Analysis of 22 Microlensing Parallax Candidates
We attempt to identify all microlensing parallax events for which the
parallax fit improves \Delta\chi^2 > 100 relative to a standard microlensing
model. We outline a procedure to identify three types of discrete degeneracies
(including a new one that we dub the ``ecliptic degeneracy'') and find many new
degenerate solutions in 16 previously published and 6 unpublished events. Only
four events have one unique solution and the other 18 events have a total of 44
solutions. Our sample includes three previously identified black-hole (BH)
candidates. We consider the newly discovered degenerate solutions and determine
the relative likelihood that each of these is a BH. We find the lens of event
MACHO-99-BLG-22 is a strong BH candidate (78%), event MACHO-96-BLG-5 is a
marginal BH candidate (37%), and MACHO-98-BLG-6 is a weak BH candidate (2.2%).
The lens of event OGLE-2003-BLG-84 may be a Jupiter-mass free-floating planet
candidate based on a weak 3 sigma detection of finite-source effects. We find
that event MACHO-179-A is a brown dwarf candidate within ~100 pc of the Sun,
mostly due to its very small projected Einstein radius, \tilde r_E = 0.23+-0.05
AU. As expected, these microlensing parallax events are biased toward lenses
that are heavier and closer than average. These events were examined for
xallarap (or binary-source motion), which can mimic parallax. We find that 23%
of these events are strongly affected by xallarap.Comment: 69 Pages, 10 Figures, 24 Tables, Submitted to Ap
The OGLE Collection of Variable Stars. One Thousand Heartbeat Stars in the Galactic Bulge and Magellanic Clouds
We present a collection of 991 heartbeat star (HBS) candidates found in the
Optical Gravitational Lensing Experiment (OGLE) project data archive. We
discuss the selection process of the HBS candidates and the structure of the
catalog itself. It consists of 512 stars located toward the Galactic bulge
(GB), 439 stars located in the Large Magellanic Cloud (LMC), and 40 in the
Small Magellanic Cloud (SMC). The collection contains two large groups of HBSs
with different physical properties. The main distinction between the two groups
is the evolutionary status of the primary star. The first group of about 100
systems contains a hot main-sequence (MS) or a Hertzsprung-gap primary star,
while the second group of about 900 systems includes a red giant (RG). For each
star, we provide two-decade-long time-series photometry, in the Cousins -
and Johnson -band filters, obtained by the OGLE project. We also present
basic observational information as well as orbital parameters derived from the
light curve modeling.Comment: 15 pages, 10 figures, 5 tables, submitted to AAS Journals. The full
machine-readable tables and links to the catalog will be available after the
acceptance of the pape
OGLE-ing the Magellanic System: RR Lyrae Stars in the Bridge
We use the extended and updated Optical Gravitational Lensing Experiment (OGLE) Collection of Variable Stars to thoroughly analyze the distribution of RR Lyrae stars in the Magellanic Bridge. We use photometric metallicities to derive the absolute Wesenheit magnitude and individual distance of each RR Lyrae star. We confirm results from our earlier study showing that RR Lyrae stars are present in between the Magellanic Clouds, though their three-dimensional distribution more resembles two extended overlapping structures than a strict bridge-like connection. The contours do connect in the southern parts of the Bridge, albeit on a level too low to state that an evident connection exists. To test the sample numerically, we use multi-Gaussian fitting and conclude that there is no additional population or overdensity located in the Bridge. We also try to reproduce results on the putative RR Lyrae Magellanic Bridge stream by selecting RR Lyrae candidates from Gaia Data Release 1. We show that we are not able to obtain the evident connection of the Clouds without many spurious sources in the sample, as the cuts are not able to remove artifacts without eliminating the evident connection at the same time. Moreover, for the first time, we present the Gaia Data Release 2 RR Lyrae stars in the Magellanic Bridge area and show that their distribution matches our results
OGLE-ing the Magellanic System: RR Lyrae Stars in the Bridge
We use the extended and updated Optical Gravitational Lensing Experiment (OGLE) Collection of Variable Stars to thoroughly analyze the distribution of RR Lyrae stars in the Magellanic Bridge. We use photometric metallicities to derive the absolute Wesenheit magnitude and individual distance of each RR Lyrae star. We confirm results from our earlier study showing that RR Lyrae stars are present in between the Magellanic Clouds, though their three-dimensional distribution more resembles two extended overlapping structures than a strict bridge-like connection. The contours do connect in the southern parts of the Bridge, albeit on a level too low to state that an evident connection exists. To test the sample numerically, we use multi-Gaussian fitting and conclude that there is no additional population or overdensity located in the Bridge. We also try to reproduce results on the putative RR Lyrae Magellanic Bridge stream by selecting RR Lyrae candidates from Gaia Data Release 1. We show that we are not able to obtain the evident connection of the Clouds without many spurious sources in the sample, as the cuts are not able to remove artifacts without eliminating the evident connection at the same time. Moreover, for the first time, we present the Gaia Data Release 2 RR Lyrae stars in the Magellanic Bridge area and show that their distribution matches our results
Reddening and Extinction Toward the Galactic Bulge from OGLE-III: The Inner Milky Way's Rv ~ 2.5 Extinction Curve
We combine VI photometry from OGLE-III with VVV and 2MASS measurements of
E(J-K_{s}) to resolve the longstanding problem of the non-standard optical
extinction toward the Galactic bulge. We show that the extinction is well-fit
by the relation A_{I} = 0.7465*E(V-I) + 1.3700*E(J-K_{s}), or, equivalently,
A_{I} = 1.217*E(V-I)(1+1.126*(E(J-K_{s})/E(V-I)-0.3433)). The optical and
near-IR reddening law toward the inner Galaxy approximately follows an R_{V}
\approx 2.5 extinction curve with a dispersion {\sigma}_{R_{V}} \approx 0.2,
consistent with extragalactic investigations of the hosts of type Ia SNe.
Differential reddening is shown to be significant on scales as small as as our
mean field size of 6', with the 1{\sigma} dispersion in reddening averaging 9%
of total reddening for our fields. The intrinsic luminosity parameters of the
Galactic bulge red clump (RC) are derived to be (M_{I,RC}, \sigma_{I,RC,0},
(V-I)_{RC,0}, \sigma_{(V-I)_{RC}}, (J-K_{s})_{RC,0}) = (-0.12, 0.09, 1.06,
0.121, 0.66). Our measurements of the RC brightness, brightness dispersion and
number counts allow us to estimate several Galactic bulge structural
parameters. We estimate a distance to the Galactic center of 8.20 kpc,
resolving previous discrepancies in distance determinations to the bulge based
on I-band observations. We measure an upper bound on the tilt {\alpha} \approx
40{\deg}. between the bar's major axis and the Sun-Galactic center line of
sight, though our brightness peaks are consistent with predictions of an N-body
model oriented at {\alpha} \approx 25{\deg}. The number of RC stars suggests a
total stellar mass for the Galactic bulge of 2.0*10^{10} M_{\odot}, if one
assumes a Salpeter IMF.Comment: 61 Pages, 21 Figures, 4 Tables, Submitted to The Astrophysical
Journal and modified as per a referee report. Includes reddening, reddening
law, differential reddening, mean distance, dispersion in distance, surface
density of stars and errors thereof for ~9,000 bulge sightlines. For a brief
video explaining the key result of this paper, see
http://www.youtube.com/user/OSUAstronom
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