557 research outputs found
Cataclysmic Variables from USNO-B1.0 Catalog: Stars with Outbursts on Infrared Palomar Plates
The search was performed for cataclysmic variable stars with outlying
infrared magnitudes in USNO-B1.0 catalog. The selection was limited to objects
in the Northern hemisphere with (B1-R1) 3.5. The search method
is described, and the details on individual stars are given. In total 27
variable objects were found with 20 being the previously known ones and 7 - new
discoveries. 4 of newly found variables are dwarf novae, while the remaining 3
- pulsating red variables of Mira or semi-regular types, including a heavily
reddened one in Pelican nebula. The correct pulsation period is determined for
two stars discovered by other researchers, and the dwarf nova nature is
confirmed for another object previously suspected as such. The perspectives of
the proposed search technique in the framework of Virtual Observatory are also
discussed.Comment: 8 pages, 10 figures, submitted to Astronomy Letter
Identification of new cataclysmic variables in the 1RXS and USNO-B1.0 catalogs
As a result of applying the original optical variability search method on
publicly available data, we have found eight new cataclysmic variables and two
possible Optically Violent Variable quasars among the previously unidentified
X-ray sources in the ROSAT catalog. We describe the search method and present
the characteristics of the newly identified variable stars. The obtained
results demonstrate the large potential of the concept of Virtual Observatory
for identifying new objects of astrophysical interest.Comment: 16 pages, 11 figures, 2 tables; submitted to Astronomy Letter
New Cataclysmic Variable 1RXS J073346.0+261933 in Gemini
In course of the search for the optical identifications associated with ROSAT
X-ray sources we have found a highly variable object with the very unusual
long-term behavior, color indices and high X-ray-to-optical flux ratio. We
report the archival photometric light curve from the Catalina Sky Survey,
optical spectroscopy from RTT150 and time-resolved photometry from
Astrotel-Caucasus telescope. The object appears to be the magnetic cataclysmic
variable (polar) with orbital period of P=3.20 hr.Comment: 8 pages, 5 figures. Submitted to Astronomy Letter
Fast chromatin immunoprecipitation assay
Chromatin immunoprecipitation (ChIP) is a widely used method to explore in vivo interactions between proteins and DNA. The ChIP assay takes several days to complete, involves several tube transfers and uses either phenol–chlorophorm or spin columns to purify DNA. The traditional ChIP method becomes a challenge when handling multiple samples. We have developed an efficient and rapid Chelex resin-based ChIP procedure that dramatically reduces time of the assay and uses only a single tube to isolate PCR-ready DNA. This method greatly facilitates the probing of chromatin changes over many time points with several antibodies in one experiment
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