1,102 research outputs found
More on Rainbow Cliques in Edge-Colored Graphs
In an edge-colored graph , a rainbow clique is a -complete
subgraph in which all the edges have distinct colors. Let and be
the number of edges and colors in , respectively. In this paper, we show
that for any , if and , then for
sufficiently large , the number of rainbow cliques in is
.
We also characterize the extremal graphs without a rainbow clique ,
for , when is maximum.
Our results not only address existing questions but also complete the
findings of Ehard and Mohr (Ehard and Mohr, Rainbow triangles and cliques in
edge-colored graphs. {\it European Journal of Combinatorics, 84:103037,2020}).Comment: 16page
Gas kinematics and star formation in the filamentary molecular cloud G47.06+0.26
We performed a multi-wavelength study toward the filamentary cloud
G47.06+0.26 to investigate the gas kinematics and star formation. We present
the 12CO (J=1-0), 13CO (J=1-0) and C18O (J=1-0) observations of G47.06+0.26
obtained with the Purple Mountain Observation (PMO) 13.7 m radio telescope to
investigate the detailed kinematics of the filament. The 12CO (J=1-0) and 13CO
(J=1-0) emission of G47.06+0.26 appear to show a filamentary structure. The
filament extends about 45 arcmin (58.1 pc) along the east-west direction. The
mean width is about 6.8 pc, as traced by the 13CO (J=1-0) emission. G47.06+0.26
has a linear mass density of about 361.5 Msun/pc. The external pressure (due to
neighboring bubbles and H II regions) may help preventing the filament from
dispersing under the effects of turbulence. From the velocity-field map, we
discern a velocity gradient perpendicular to G47.06+0.26. From the Bolocam
Galactic Plane Survey (BGPS) catalog, we found nine BGPS sources in
G47.06+0.26, that appear to these sources have sufficient mass to form massive
stars. We obtained that the clump formation efficiency (CFE) is about 18% in
the filament. Four infrared bubbles were found to be located in, and adjacent
to, G47.06+0.26. Particularly, infrared bubble N98 shows a cometary structure.
CO molecular gas adjacent to N98 also shows a very intense emission. H II
regions associated with infrared bubbles can inject the energy to surrounding
gas. We calculated the kinetic energy, ionization energy, and thermal energy of
two H II regions in G47.06+0.26. From the GLIMPSE I catalog, we selected some
Class I sources with an age of about 100000 yr, which are clustered along the
filament. The feedback from the H II regions may cause the formation of a new
generation of stars in filament G47.06+0.26.Comment: 10 pages, 11 figures, accepted for publication in A&
Pebbles in an Embedded Protostellar Disk: The Case of CB26
Planetary cores are thought to form in proto-planetary disks via the growth
of dusty solid material. However, it is unclear how early this process begins.
We study the physical structure and grain growth in the edge-on disk that
surrounds the ~1 Myr old low-mass (~0.55 Msun) protostar embedded in the Bok
Globule CB26 to examine how much grain growth has already occurred in the
protostellar phase. We combine the SED between 0.9 m and 6.4 cm with
high angular resolution continuum maps at 1.3, 2.9, and 8.1 mm, and use the
radiative transfer code RADMC-3D to conduct a detailed modelling of the dust
emission from the disk and envelope of CB 26. We infer inner and outer disk
radii of around 16 au and 17222 au, respectively. The total gas mass in
the disk is ~0.076 Msun, which amounts to ~14% of the mass of the central star.
The inner disk contains a compact free-free emission region, which could be
related to either a jet or a photoevaporation region. The thermal dust emission
from the outer disk is optically thin at mm wavelengths, while the emission
from the inner disk midplane is moderately optically thick. Our best-fit
radiative transfer models indicate that the dust grains in the disk have
already grown to pebbles with diameters of the order of 10 cm in size. Residual
8.1 mm emission suggests the presence of even larger particles in the inner
disk. For the optically thin mm dust emission from the outer disk, we derive a
mean opacity slope of 0.60.4, which is consistent with the presence of
large dust grains. The presence of cm-sized bodies in the CB 26 disk indicates
that solids grow rapidly already during the first million years in a
protostellar disk. It is thus possible that Class II disks are already seeded
with large particles and may contain even planetesimals.Comment: Accepted for publication in A&A; 17 pages, 14 figure
The chaperone activity of trigger factor is distinct from its isomerase activity during co-expression with adenylate kinase in Escherichia coli
AbstractTo investigate the molecular chaperone function of trigger factor (TF) and its relationship with isomerase activity in vivo, the assisted folding of adenylate kinase (AK) by TF in Escherichia coli was examined by measuring the amounts of soluble AK produced during co-expression. When the mutant of chicken AK, P17G, is expressed in plasmid pBVAK, 95% of the protein is found in inclusion bodies. Co-expression of AK with TF was achieved using a plasmid pBVAT that allowed expression of TF and AK in the same plasmid under separate control. Co-expression with TF resulted in an increase in the amount of soluble AK, with a higher increase when TF was expressed at higher levels in the cell. Co-expression of AK with the two TF mutants, Y221G and F233Y, in which peptidyl-prolyl cis/trans isomerase activity was 1% of wild-type, gave the same results as wild-type TF. This provides in vivo evidence that the molecular chaperone activity of TF is distinct from its isomerase activity
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