5,975 research outputs found
Retrograde Accretion and Merging Supermassive Black Holes
We investigate whether a circumbinary gas disc can coalesce a supermassive
black hole binary system in the centre of a galaxy. This is known to be
problematic for a prograde disc. We show that in contrast, interaction with a
retrograde circumbinary disc is considerably more effective in shrinking the
binary because there are no orbital resonances. The binary directly absorbs
negative angular momentum from the circumbinary disc by capturing gas into a
disc around the secondary black hole, or discs around both holes if the binary
mass ratio is close to unity. In many cases the binary orbit becomes eccentric,
shortening the pericentre distance as the eccentricity grows. In all cases the
binary coalesces once it has absorbed the angular momentum of a gas mass
comparable to that of the secondary black hole. Importantly, this conclusion is
unaffected even if the gas inflow rate through the disc is formally
super--Eddington for either hole. The coalescence timescale is therefore always
, where is the secondary black hole mass and
the inflow rate through the circumbinary disc.Comment: 8 pages, 4 figures. Accepted for publication in MNRAS. Movies of the
simulations can be found at:
http://www.astro.le.ac.uk/users/cjn12/RetroBinaryMovies.htm
Methods of editing cloud and atmospheric layer affected pixels from satellite data
Subvisible cirrus clouds (SCi) were easily distinguished in mid-infrared (MIR) TIROS-N daytime data from south Texas and northeast Mexico. The MIR (3.55-3.93 micrometer) pixel digital count means of the SCi affected areas were more than 3.5 standard deviations on the cold side of the scene means. (These standard deviations were made free of the effects of unusual instrument error by factoring out the Ch 3 MIR noise on the basis of detailed examination of noisy and noise-free pixels). SCi affected areas in the IR Ch 4 (10.5-11.5 micrometer) appeared cooler than the general scene, but were not as prominent as in Ch 3, being less than 2 standard deviations from the scene mean. Ch 3 and 4 standard deviations and coefficients of variation are not reliable indicators, by themselves, of the presence of SCi because land features can have similar statistical properties
Seven years of marine environmental changes monitoring at coastal OOCS stations (Catalan Sea, NW Mediterranean)
Since March 2009 up to the present (more than 7 years now), the
Operational Observatory of the Catalan Sea (OOCS; http://www2.ceab.csic.es/
oceans/) remains a witness of persistent marine environmental changes. The OOCS
has two fixed observation stations at the head of the Blanes Canyon (200 m depth,
41.66°N; 2.91°E) and at the Blanes bay (20 m depth, 41.67°N; 2.80°E) in the Catalan
Sea, NW Mediterranean. At the canyon station, a multi-parametric buoy presently
installed delivers high frequency (by 30 min) and multi-parametric oceanographic
(i.e. salinity, temperature, chlorophyll, turbidity, as well as light intensity in the
PAR range for the upper 50 m depth) and atmospheric (air temperature, relative
humidity, wind speed and direction and PAR) data. Subsurface photos and videos
by an IP high resolution fisheye camera attached to the buoy are also delivered
at 4-hour basis. Data and multimedia are transmitted in near real time for public
access, via combined GSM/GPRS and 3G connections. At both stations, CTD profiles
and water samples (collected for nutrients and picoplankton analyses) are carried
out on board a research vessel at fortnightly basis. Numerical simulations along
with the time series of in-situ observations show inter-annual seasonality anomalies
possibly linked to global environmental changes. The lower-atmosphere and
upper-sea environmental time series data collected prove the occurrence of shifting
patterns of heat and matter fluxes impacting pelagic and benthic organisms.Peer Reviewe
Analisa Faktor yang Mempengaruhi Kepuasan Kerja Karyawan di Kantor Konsultan Pajak Surabaya pada Tahun 2013
Tujuan penelitian ini adalah untuk mengetahui apakah faktor motivasi dan faktor hygiene mempunyai pengaruh terhadap kepuasan kerja karyawan konsultan pajak. Data diperoleh dari kuesioner yang diisi oleh responden yang bekerja di kantor konsultan pajak dengan jabatan junior di kota Surabaya. Sebanyak 42 kuesioner kembali dengan keadaan yang lengkap dan dapat diolah. Dengan menggunakan structural equation modeling, hasil penelitian menunjukkan bahwa faktor motivasi tidak berpengaruh terhadap kepuasan kerja karyawan di kantor konsultan pajak dan faktor hygiene berpengaruh terhadap kepuasan kerja karyawan
Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions
There are no author-identified significant results in this report
Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions
There are no author-identified significant results in this report
AgRISTARS: Early warning and crop condition assessment. Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions
Emissive (10.5 to 12.5 microns) and reflective (0.55 to 1.1 microns) data for ten day scenes and infrared data for six night scenes of southern Texas were analyzed for plant cover, soil temperature, freeze, water stress, and evapotranspiration. Heat capacity mapping mission radiometric temperatures were: within 2 C of dewpoint temperatures, significantly correlated with variables important in evapotranspiration, and related to freeze severity and planting depth soil temperatures
Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions
There are no author-identified significant results in this report
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