1,109 research outputs found
Machine-learning identification of galaxies in the WISExSuperCOSMOS all-sky catalogue
The two currently largest all-sky photometric datasets, WISE and SuperCOSMOS,
were cross-matched by Bilicki et al. (2016) (B16) to construct a novel
photometric redshift catalogue on 70% of the sky. Galaxies were therein
separated from stars and quasars through colour cuts, which may leave
imperfections because of mixing different source types which overlap in colour
space. The aim of the present work is to identify galaxies in the
WISExSuperCOSMOS catalogue through an alternative approach of machine learning.
This allows us to define more complex separations in the multi-colour space
than possible with simple colour cuts, and should provide more reliable source
classification. For the automatised classification we use the support vector
machines learning algorithm, employing SDSS spectroscopic sources cross-matched
with WISExSuperCOSMOS as the training and verification set. We perform a number
of tests to examine the behaviour of the classifier (completeness, purity and
accuracy) as a function of source apparent magnitude and Galactic latitude. We
then apply the classifier to the full-sky data and analyse the resulting
catalogue of candidate galaxies. We also compare thus produced dataset with the
one presented in B16. The tests indicate very high accuracy, completeness and
purity (>95%) of the classifier at the bright end, deteriorating for the
faintest sources, but still retaining acceptable levels of 85%. No significant
variation of classification quality with Galactic latitude is observed.
Application of the classifier to all-sky WISExSuperCOSMOS data gives 15 million
galaxies after masking problematic areas. The resulting sample is purer than
the one in B16, at a price of lower completeness over the sky. The automatic
classification gives a successful alternative approach to defining a reliable
galaxy sample as compared to colour cuts.Comment: 12 pages, 15 figures, accepted for publication in A&A. Obtained
catalogue will be included in the public release of the WISExSuperCOSMOS
galaxy catalogue available from http://ssa.roe.ac.uk/WISExSCO
Preliminary effects of fertilization on ecochemical soil condition in mature spruce stands experiencing dieback in the Beskid Śla̧ski and Żywiecki Mountains, Poland
In recent years, there has been the phenomena of spruce dieback in Europe. Significant areas of spruce low mortality now cover both sides of the Polish southern border. We evaluated ecochemical parameters influencing the heavy dieback occurring in mature spruce stands in the Polish Carpathian Mountains. Dolomite, magnesite and serpentinite fertilizers were applied to experimental plots located in 100-year-old stands in the autumn of 2008. The experimental plots were located in the mid-elevational forest zone (900-950 m) on two nappes of the flysch Carpathians: Magura (Ujsoły Forest District) and Silesian (Wisła Forest District). The saturation of the studied soils demonstrates moderate resilience of soils in Wisła Forest District in relation to acid load and high flexibility of the Ujsoły soils. After application of the fertilizers, an increase of Mg, Ca and Mb was noted in the soil solution, determined in the overlaying highly acidic organic horizons through the ion-exchange buffering mechanism of highly protonated functional groups with high buffering capacity. Magnesium concentration increased following fertilization, presenting a potential improvement of forest growth capacity without the hazard of adverse side effects of liming. Aluminium stress in old spruce is unlikely, while trees in the control plots in Wisła Forest District may already be sensitive to aluminium stress. Serpentinite fertilization improved the supply of soils in magnesium without causing significant changes in the pH of the soil. Such changes in the pH were found in dolomite and magnesite fertilizer. © The Author(s) 2014
Aplazja prawej tętnicy płucnej z krążeniem obocznym od tętnicy wieńcowej zaopatrującym hipoplastyczne płuco
[Ultra] Luminous Infrared Galaxies selected at 90 m in the AKARI deep field: a study of AGN types contributing to their infrared emission
The aim of this work is to characterize physical properties of Ultra Luminous
Infrared Galaxies (ULIRGs) and Luminous Infrared Galaxies (LIRGs) detected in
the far-infrared (FIR) 90um band in the AKARI Deep Field-South (ADF-S) survey.
In particular, we want to estimate the AGN contribution to the [U]LIRGs'
infrared emission and which types of AGNs are related to their activity. We
examined 69 galaxies at z>0.05 detected at 90um by the AKARI satellite in the
ADF-S, with optical counterparts and spectral coverage from the ultraviolet to
the FIR. We used two independent spectral energy distribution fitting codes:
one fitting the SED from FIR to FUV (CIGALE) and gray-body + power spectrum fit
for the infrared part of the spectra (CMCIRSED) in order to identify a
subsample of [U]LIRGs, and to estimate their properties. Based on the CIGALE
SED fitting, we have found that [U]LIRGs selected at the 90um AKARI band
compose ~56% of our sample (we found 17 ULIRGs and 22 LIRGs, spanning over the
redshift range 0.06<z<1.23). Their physical parameters, such as stellar mass,
star formation rate (SFR), and specific SFR are consistent with the ones found
for other samples selected at IR wavelengths. We have detected a significant
AGN contribution to the MIR luminosity for 63% of LIRGs and ULIRGs. Our LIRGs
contain Type 1, Type 2, and intermediate types of AGN, whereas for ULIRGs, a
majority (more than 50%) of AGN emission originates from Type 2 AGNs. The
temperature--luminosity and temperature--mass relations for the dust component
of ADF--S LIRGs and ULIRGs indicate that these relations are shaped by the dust
mass and not by the increased dust heating. We conclude that LIRGs contain Type
1, Type 2, and intermediate types of AGNs, with an AGN contribution to the MIR
emission at the median level of 13+/-3%, whereas the majority of ULIRGs contain
Type 2 AGNs, with a median AGN fraction equal to 19+/-8%.Comment: 24 pages, 21 figures, accepted for publication in Astronomy &
Astrophysic
Usefulness of three-dimensional echocardiography for the assessment of ventricular function in children: Comparison with cardiac magnetic resonance, with a focus on patients with arrhythmia
Background: Focusing on patients with arrhythmia, the aims of this study was to assess ventricular function in children using three-dimensional echocardiography (3D-ECHO) and to compare the results to those obtained with cardiac magnetic resonance (CMR).Methods: The study group consisted of 43 children in whom 3D-ECHO and CMR were performed. Twenty-five patients had a ventricular arrhythmia, 7 left ventricular cardiomyopathies, 9 proved to be healthy. In all children, 3D-ECHO (offline analysis) was used to assess ventricular ejection fraction (EF). The results were compared to CMR using the Bland-Altman analysis and linear regression. The Student paired T-test was used to compare of means between both modalities.Results: The relation between the results derived from both methods is linear (for left ventricle: estimated slope = 1.031, p < 0.0001, R-squared = 0.998; for right ventricle: estimated slope = 0.993, p < 0.0001, R-squared = 0.998). In spite of minimal mean differences between results for both ventricles and narrow 95% confidence intervals, the paired t-test proved those differences not to be significant (p > 0.05) for the right ventricle but statistically significant (p < 0.05) for the left ventricle, for which the left ventricular EF calculated in 3D-ECHO was systematically underestimated with a mean difference of –1.8% ± 2.6% (p < 0.0001).Conclusions: Three-dimensional echocardiography assessment of both left and right ventricular EF in children showed high significant correlation and agreement with CMR. 3D-ECHO could be a valuable tool in follow-up of children with arrhythmic disorders requiring regular assessment of ventricular function
Absolute properties of BG Ind - a bright F3 system just leaving the Main Sequence
We present photometric and spectroscopic analysis of the bright detached
eclipsing binary BG Ind. The masses of the components are found to be 1.428 +-
0.008 and 1.293 +- 0.008 Msun and the radii to be 2.290+-0.017 and 1.680+-0.038
Rsun for primary and secondary stars, respectively. Spectra- and
isochrone-fitting coupled with color indices calibration yield
[Fe/H]=-0.2+-0.1. At an age of 2.65+-0.20 Gyr BG Ind is well advanced in the
main-sequence evolutionary phase - in fact, its primary is at TAMS or just
beyond it. Together with three similar systems (BK Peg, BW Aqr and GX Gem) it
offers an interesting opportunity to test the theoretical description of
overshooting in the critical mass range 1.2-1.5 Msun.Comment: 8 pages, 5 figures, corrected bugs in author lis
Fascinating fructophilic lactic acid bacteria associated with various fructose-rich niches
Fructophilic lactic acid bacteria (FLAB) are recently described group of lactic acid bacteria (LAB) that prefer fructose instead of glucose as a carbon source. FLAB have been isolated from fructose-rich niches such as flowers, fruits, fermented fruits, and gastrointestinal tracts of insects whose diet is based on fructose. These bacteria are divided into obligate and facultative fructophilc lactobacilli based on biochemical features. All FLAB are heterofermentative microorganisms, which during fermentation of carbohydrates, in addition to lactic acid, produce also acetic acid, and alcohol as end-products. The fructophilic bacteria, inhabiting the honeybee guts positively impact the health of their hosts, improve their longevity, and are promising probiotic candidates. These symbionts of honeybees play a key role in the production of honey by bees and are present in a large number in fresh honey. The combination of osmolarity with antibacterial, and therapeutic properties of these bacteria make fresh honey optimal alternative for future wound healing
Unsupervised classification reveals new evolutionary pathways
While we already seem to have a general scenario of the evolution of
different types of galaxies, a complete and satisfactory understanding of the
processes that led to the formation of all the variety of today's galaxy types
is still beyond our reach. To solve this problem, we need both large datasets
reaching high redshifts and novel methodologies for dealing with them. The
VIPERS survey statistical power, which observed galaxies at , and the application of an unsupervised clustering algorithm allowed us to
distinguish 12 galaxy classes. Studies of their environmental dependence
indicate that this classification may actually reflect different galaxy
evolutionary paths. For instance, a class of the most passive red galaxies
gathers galaxies smaller than other red galaxies of a similar
stellar mass, revealing the first sample of red nuggets at intermediate
redshift. On the other end, a class of blue dwarf galaxies is composed mainly
of AGN, challenging commonly used mid-infrared AGN selections.Comment: Accepted for publication in the ML4ASTRO (ICML 2022) proceeding boo
The Cardiac Effects of Performance-Enhancing Medications: Caffeine vs. Anabolic Androgenic Steroids.
Several performance-enhancing or ergogenic drugs have been linked to both significant adverse cardiovascular effects and increased cardiovascular risk. Even with increased scrutiny on the governance of performance-enhancing drugs (PEDs) in professional sport and heightened awareness of the associated cardiovascular risk, there are some who are prepared to risk their use to gain competitive advantage. Caffeine is the most commonly consumed drug in the world and its ergogenic properties have been reported for decades. Thus, the removal of caffeine from the World Anti-Doping Agency (WADA) list of banned substances, in 2004, has naturally led to an exponential rise in its use amongst athletes. The response to caffeine is complex and influenced by both genetic and environmental factors. Whilst the evidence may be equivocal, the ability of an athlete to train longer or at a greater power output cannot be overlooked. Furthermore, its impact on the myocardium remains unanswered. In contrast, anabolic androgenic steroids are recognised PEDs that improve athletic performance, increase muscle growth and suppress fatigue. Their use, however, comes at a cost, afflicting the individual with several side effects, including those that are detrimental to the cardiovascular system. This review addresses the effects of the two commonest PEDs, one legal, the other prohibited, and their respective effects on the heart, as well as the challenge in defining its long-term implications
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