892 research outputs found
Attenuation Laws for Galaxies with Different Star Formation Histories, Based on the SDSS Images
Attenuation curves (laws) in the optical part of thespectrum (from about 3500 AA~to 9000 AA) are determined for galaxieswith different star formation histories (SFHs) using images in five photometrical bands from the Sloan Digital Sky Survey (SDSS). Owing to large surveys like SDSS, it is possible to defineseveral subgroups of galaxies with similar SFHs using two spectralindices that trace SFH. Attenuation curves are analyzed in termsof SFH and compared to the curves that are often used for dustcorrection of the observed data
Gaia science alerts and the observing facilities of the Serbian-Bulgarian mini-network telescopes
The astrometric European Space Agency (ESA) Gaia mission was launched in
December 19, 2013. One of the tasks of the Gaia mission is production of an
astrometric catalog of over one billion stars and more than 500000
extragalactic sources. The quasars (QSOs), as extragalactic sources and radio
emitters, are active galactic nuclei objects (AGNs) whose coordinates are
well determined via Very Long Baseline Interferometry (VLBI) technique and
may reach sub-milliarcsecond accuracy. The QSOs are the defining sources of
the quasi-inertial International Celestial Reference Frame (ICRF) because of
their core radio morphology, negligible proper motions (until
sub-milliarcsecond per year), and apparent point-like nature. Compact AGNs,
visible in optical domain, are useful for a direct link of the future Gaia
optical reference frame with the most accurate radio one. Apart from the
above mentioned activities, Gaia has other goals such as follow-up of
transient objects. One of the most important Gaia's requirements for
photometric alerts is a fast observation and reduction response, that is,
submition of observations within 24 hours. For this reason we have developed
a pipeline. In line with possibilities of our new telescope
(D(cm)/F(cm)=60/600) at the Astronomical Station Vidojevica (ASV, of the
Astronomical Observatory in Belgrade), we joined the Gaia-Follow-Up Network
for Transients Objects (Gaia-FUN-TO) for the photometric alerts. Moreover, in
view of the cooperation with Bulgarian colleagues (in the frst place, SV),
one of us (GD) initiated a local mini-network of Serbian { Bulgarian
telescopes useful for the Gaia-FUN-TO and other astronomical purposes. During
the next year we expect a new 1.4 m telescope at ASV site. The speed of data
processing (from observation to calibration server) could be one day. Here,
we present an overview of our activities in the Gaia-FUN-TO which includes
establishing Serbian { Bulgarian mini-network (of five telescopes at three
sites, ASV in Serbia, Belogradchik and Rozhen in Bulgaria), the Gaia-FUN-TO
test observations, and some results. [Projekat Ministarstva nauke Republike
Srbije, br. 176011: Dynamics and kinematics of celestial bodies and systems,
br. 176004: Stellar physics, i br. 176021: Visible and invisible matter in
nearby galaxies: theory and observations
Pengaruh Partisipasi Anggaran terhadap Senjangan Anggaran dengan Variabel Asimetri Informasi, Ketidakpastian Strategik dan Gaya Kepemimpinan sebagai Variabel Moderating (Studi Empiris pada Rumah Sakit Swasta di Provinsi Riau)
Purpose of this study was to examine the effect of budget participation on budgetary slack with information asymmetry, uncertainty of strategic and leadership style as moderating variable. The location study this object is a private hospital located in Riau Province. While the timing of this study in November 2015. The population in this study are a private hospitals located in Riau Province. Data used in this study are primary data. Data collection method used in this research is to use the instrument in the form of a questionnaire which was given the leadership of the hospital. The analytical method used in this study is multiple regression analysis. Based on the data collected and testing has been done on the problem by using regression analysis method, it can be concluded: 1) Participation budget significantly influence budgetary slack. 2) The interaction between budgetary participation and asymmetry of information has an effect on budgetary slack, so the information asymmetry is a moderating variable. 3) The interaction between budgetary participation and strategic uncertainty has an effect on budgetary slack, so strategic uncertainty is a moderating variable. 4) The interaction between budgetary participation and leadership style has no effect on budgetary slack, so the style of leadership is not a moderating variable
Multi-band optical variability of three TeV Blazars on Diverse Timescales
We present our optical photometric observations of three TeV blazars, PKS
1510-089, PG 1553+113 and Mrk 501 taken using two telescopes in India, one in
Bulgaria, one in Greece and one in Serbia during 2012 - 2014. These
observations covered a total of 95 nights with a total of 202 B filter frames,
247 images in V band, 817 in R band while 229 images were taken in the I
filter. This work is focused on multi-band flux and colour variability studies
of these blazars on diverse timescales which are useful in understanding the
emission mechanisms. We studied the variability characteristics of above three
blazars and found all to be active over our entire observational campaigns. We
also searched for any correlation between the brightness of the sources and
their colour indices. During the times of variability, no significant evidence
for the sources to display spectral changes correlated with magnitude was found
on timescales of a few months. We briefly discuss the possible physical
mechanisms most likely responsible for the observed flux variability.Comment: 11 pages, 7 figures, 9 tables. Accepted for publication in MNRA
Entirely off-grid and solar-powered DNA sequencing of microbial communities during an ice cap traverse expedition
Microbial communities in remote locations remain under-studied. This is particularly true on glaciers and icecaps, which cover approximately 11% of the Earth’s surface. The principal reason for this is the inaccessibility of most of these areas due to their extreme isolation and challenging environmental conditions. While remote research stations have significantly lowered the barrier to studying the microbial communities on icecaps, their use has led to a bias for data collection in the near vicinity of these institutions. Here, miniaturisation of a DNA sequencing lab suitable for off-grid metagenomic studies is demonstrated. Using human power alone, this lab was transported across Europe’s largest ice cap (Vatnajökull, Iceland) by ski and sledge. After 11 days of unsupported polar-style travel, a metagenomic study of a geothermal hot spring gorge was conducted on the remote northern edge of the ice cap. This tent-based metagenomic study resulted in over 24 h of Nanopore sequencing, powered by solar power alone. This study demonstrates the ability to conduct DNA sequencing in remote locations, far from civilised resources (mechanised transport, external power supply, internet connection, etc.), whilst greatly reducing the time from sample collection to data acquisition
A Deep Learning Framework for Disentangling Triangle Singularity and Pole-Based Enhancements
Enhancements in the invariant mass distribution or scattering cross-section
are usually associated with resonances. However, the nature of exotic signals
found near hadron-hadron thresholds remain a puzzle today. In fact, a purely
kinematic triangle mechanism is also capable of producing similar structures,
but do not correspond to any unstable quantum state. In this paper, we report
for the first time, that a deep neural network can be trained to distinguish
triangle singularity from pole-based enhancements. We also identify the type of
dynamic pole structure that can be misidentified as triangle enhancement. We
apply our method to confirm that the state is not due to a
single triangle singularity, and is more favored towards a pole-based
interpretation based solely on pure line-shape analysis. Lastly, we argue how
our method can be used as a model-selection framework to help in classifying
other exotic hadron candidates.Comment: 14 pages, 12 figures; added reference
On the solar abundance of indium
The generally adopted value for the solar abundance of indium is over six
times higher than the meteoritic value. We address this discrepancy through
numerical synthesis of the 451.13 nm line on which all indium abundance studies
are based, both for the quiet-sun and the sunspot umbra spectrum, employing
standard atmosphere models and accounting for hyperfine structure and Zeeman
splitting in detail. The results, as well as a re-appraisal of indium
nucleosynthesis, suggest that the solar indium abundance is close to the
meteoritic value, and that some unidentified ion line causes the 451.13 nm
feature in the quiet-sun spectrum.Comment: 7 pages, 9 figures, accepted for publication in MNRAS Main Journa
Impacts of different treatment methods for cattle manure on the spread of faecal indicator organisms from soil to lettuce in Nigeria
ACKNOWLEDGEMENTS We are grateful for the funding provided by the Federation of European Microbiology Societies (FEMS) and the School of Biological Sciences, University of Aberdeen. Funding information Federation of European Microbiological Societies; University of Aberdeen Open Access via UoA Wiley agreement.Peer reviewedPublisher PD
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