68 research outputs found
Transverse decoherence and coherent spectra in long bunches with space charge
The transverse bunch spectrum and the transverse decoherence/recoherence
following an initial bunch offset are important phenomena in synchrotrons and
storage rings, and are widely used for beam and lattice measurements.
Incoherent shifts of the particles betatron frequency and of the synchrotron
frequency modify the transverse spectrum and the bunch decoherence. In this
study we analyze the effects of transverse space charge and of the rf
nonlinearity on the decoherence signals. The transverse bunch decoherence and
the resulting coherent spectra are measured in the SIS18 synchrotron at GSI
Darmstadt for different bunch parameters. Particle tracking simulations
together with an analytical model are used to describe the modifications in the
decoherence signals and in the coherent spectra due to space charge and the rf
bucket nonlinearity.Comment: Submitted on May 7 2012 to Physical Review Special Topics -
Accelerators and Beam
MASTER prompt and follow-up GRB observations
There are the results of gamma-ray bursts observations obtained using the
MASTER robotic telescope in 2007 - 2009. We observed 20 error-boxes of
gamma-ray bursts this period.The limits on their optical brightnesses have been
derived. There are 5 prompt observations among them, obtained at our very wide
field cameras. Also we present the results of the earliest observations of the
optical emission of the gamma-ray bursts GRB 050824 and GRB 060926.Comment: 10 pages, 2 figure
Master Robotic Net
The main goal of the MASTER-Net project is to produce a unique fast sky
survey with all sky observed over a single night down to a limiting magnitude
of 19 - 20mag. Such a survey will make it possible to address a number of
fundamental problems: search for dark energy via the discovery and photometry
of supernovas (including SNIa), search for exoplanets, microlensing effects,
discovery of minor bodies in the Solar System and space-junk monitoring. All
MASTER telescopes can be guided by alerts, and we plan to observe prompt
optical emission from gamma-ray bursts synchronously in several filters and in
several polarization planes.Comment: 10 pages, 8 figure
РЕАЛЬНАЯ СТОИМОСТЬ ИПОТЕЧНОГО КРЕДИТОВАНИЯ И ПУТЬ К ЕЁ ДОСТУПНОСТИ
The article considers the availabilityof mortgage loans to the population,estimated nominal and real value of the mortgage. Describes the current patternand proposes a way to improve it.Встатьерассматриваетсядоступность ипотечного кредитования для населения, оценивается номинальная и реальная стоимость ипотечного кредита. Описывается существующая картина и предлагается путь к её улучшению
Supernova search with active learning in ZTF DR3
We provide the first results from the complete SNAD adaptive learning
pipeline in the context of a broad scope of data from large-scale astronomical
surveys. The main goal of this work is to explore the potential of adaptive
learning techniques in application to big data sets. Our SNAD team used Active
Anomaly Discovery (AAD) as a tool to search for new supernova (SN) candidates
in the photometric data from the first 9.4 months of the Zwicky Transient
Facility (ZTF) survey, namely, between March 17 and December 31 2018 (58194 <
MJD < 58483). We analysed 70 ZTF fields at a high galactic latitude and
visually inspected 2100 outliers. This resulted in 104 SN-like objects being
found, 57 of which were reported to the Transient Name Server for the first
time and with 47 having previously been mentioned in other catalogues, either
as SNe with known types or as SN candidates. We visually inspected the
multi-colour light curves of the non-catalogued transients and performed
fittings with different supernova models to assign it to a probable photometric
class: Ia, Ib/c, IIP, IIL, or IIn. Moreover, we also identified unreported
slow-evolving transients that are good superluminous SN candidates, along with
a few other non-catalogued objects, such as red dwarf flares and active
galactic nuclei. Beyond confirming the effectiveness of human-machine
integration underlying the AAD strategy, our results shed light on potential
leaks in currently available pipelines. These findings can help avoid similar
losses in future large-scale astronomical surveys. Furthermore, the algorithm
enables direct searches of any type of data and based on any definition of an
anomaly set by the expert.Comment: 22 pages with appendix, 12 figures, 2 tables, accepted for
publication in Astronomy and Astrophysic
Transient detections and other real-time data processing from wide-field chambers MASTER-VWF
At present time Robotic observatory making is of current importance. Having a
large field of view and being able to point at anywhere, Robotic astronomical
systems are indispensable when they looking for transients like grb, supernovae
explosions, novae etc, as it's impossible in these cases to foresee what you
should point you telescope at and when. In work are described prompt GRB
observations received on wide-field chambers MASTER-VWF, and also methods of
the images analysis and transients classifications applied in real-time data
processing in this experiment. For 7 months of operation 6 synchronous
observations of gamma-ray burst had been made by MASTER VWF in Kislovodsk and
Irkutsk. In all cases a high upper limits have been received (see tabl \ref
{tab_grbwf} and fig. \ref {allgrb}).Comment: 21 pages, 21 figure, 2 tables, Advances in Astronomy in pres
Structural insights into thrombolytic activity of destabilase from medicinal leech
Destabilase from the medical leech Hirudo medicinalis belongs to the family of i-type lysozymes. It has two different enzymatic activities: microbial cell walls destruction (muramidase activity), and dissolution of the stabilized fibrin (isopeptidase activity). Both activities are known to be inhibited by sodium chloride at near physiological concentrations, but the structural basis remains unknown. Here we present two crystal structures of destabilase, including a 1.1 Å-resolution structure in complex with sodium ion. Our structures reveal the location of sodium ion between Glu34/Asp46 residues, which were previously recognized as a glycosidase active site. While sodium coordination with these amino acids may explain inhibition of the muramidase activity, its influence on previously suggested Ser49/Lys58 isopeptidase activity dyad is unclear. We revise the Ser49/Lys58 hypothesis and compare sequences of i-type lysozymes with confirmed destabilase activity. We suggest that the general base for the isopeptidase activity is His112 rather than Lys58. pKa calculations of these amino acids, assessed through the 1 μs molecular dynamics simulation, confirm the hypothesis. Our findings highlight the ambiguity of destabilase catalytic residues identification and build foundations for further research of structure–activity relationship of isopeptidase activity as well as structure-based protein design for potential anticoagulant drug development.</p
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