3,471 research outputs found
Molecular Gas in the Bulge and Ring of NGC 7331
Maps of the J=2-1 12CO emission from the SbII galaxy NGC 7331 show a
low-contrast ring at a radius of about 3.5 kpc. There is no evidence for a
pronounced central hole in the CO distribution as claimed by others. The
molecular ring is just outside the radius of peak emission from warm dust, but
coincides with the peak of colder dust emission. Various 12CO and 13CO
transitions have been observed from three positions including the center, which
was also observed in the 492 GHz transition. The line measurements have been
modelled by emission from a clumpy mixture of low-density molecular gas at
about T(kin) = 10 K and high-density molecular gas at temperatures of 10 K and
20 K. The CO to H2 conversion factor in NGC 7331 is lower than that in the
Milky Way, and lowest in the center of NGC 7331. The total interstellar gas
mass is dominated by molecular hydrogen in the bulge and in the ring, and by
atomic hydrogen outside the ring. Total hydrogen mass densities in the ring are
about twice those in the bulge. Total gas to dynamic mass ratios increase from
1% in the bulge to 3% outside the ring. The bulge molecular gas may have
originated in mass loss from bulge stars, in which case the molecular ring is
probably the consequence of evacuation efficiency decreases at the outer bulge
edge.Comment: 12 pages, 4 figures, A&A in pres
Detection of Neutral Carbon in the M 31 Dark Cloud D478
Emission from the 492 GHz CI tranition was detected towards the dark cloud
D478 in M31. Using existing 12CO and 13CO measurements, models for the gas
properties of D478 are discussed. The observed CO and C line ratios can be
explained by two-component models (dense cores and tenuous envelopes);
single-density models appear less likely. The models indicate temperatures
T(kin) = 10 K. The beam-averaged C column density is 0.3 - 0.8 times that of
CO, whereas the total carbon to hydrogen ratio N(C)/N(H) = 5-3 times 10**-4.
The resulting CO-to-H2 conversion factor X is about half that of the Solar
Neighbourhood. With temperatures of about 10 K and projected mass densities of
5-10 M(sun)/pc**2 there appears to be no need to invoke the presence of very
cold and very massive clouds. Rather, D478 appears to be comparable to Milky
Way dark cloud complexes such as the Taurus-Auriga dark cloud complex.Comment: 7 Pages, 1 Figure; accepted by A&
THE VEGETATIVE ANATOMY OF KOSTERMANSIA MALAYANA SOEGENG
The anatomy of leaves, twigs, wood and seedling of Kostermansia Soegeng is described. A comparison with some species of Coelostegia and Durio indicates the close affinities between the three taxa, but also shows some differences in leaf anatomy, probably valuable for diagnostic purposes. The stomata in Kostermansia show a very remarkable arrangement in circles around the insertions of the scales
CI and CO in the Spiral Galaxies NGC 6946 and M 83
Multitransition 12CO, 13CO and 492 GHz [CI] measurements of the late-type spiral galaxies NGC 6946 and M 83 (NGC 5236) show pronounced molecular gas concentrations in rapid solid-body rotation within a few hundred parsec from both nuclei. Their 12CO, 13CO and [CI] relative intensities are nearly identical. However, the very different [CII] intensities imply that the physical conditions are not. The slow decrease of 12CO intensities with increasing rotational level marks the presence of significant amounts of warm and dense molecular gas in both galaxy centers. Detailed modelling indicates that both galaxiy centers contain at least two distinct molecular components: a warm and dense component with T(kin) = 30-60 K, n(H2) = 3000-10 000 cc, and a more tenuous hotter component with T(kin) = 100-150 K, n(H2) < 1000 cc). Atomic carbon column densities exceed CO column densities by a factor of about 1.5 in NGC 6946 and about 4 in M 83. Unlike NGC 6946, M 83 contains a significant amount of molecular hydrogen associated with ionized carbon rather than CO. The centers of NGC 6946 and M 83 contain nearly identical total (atomic and molecular) gas masses of about 3 x 10**7 M(sun). Despite their prominence, the central gas concentrations in these galaxies represent only a few per cent of the stellar mass in the same volume. The peak face-on gas mass density is much higher in M 83 (120 M(sun)/pc**2) than in NGC 6946 (45 M(sun)/pc**2). The more intense starburst in M 83 is associated with a more compact and somewhat hotter PDR zone than the milder starburst in NGC 6946
Reply: Patterns of nodal recurrence after omission of elective nodal irradiation for limited-stage small-cell lung cancer
Molecular gas temperature and density in spiral galaxies
We combine beam-matched CO-13, CO-12 J = 3 yields 2 and J = 2 yields 1 line data to infer the molecular gas excitation conditions in the central 500 to 1600 pc diameters of a small sample of infrared-bright external galaxies: NGC253, IC342, M 83, Maffei 2, and NGC6946. Additional observations of the J = 1 yields 0 lines of C-18O and CO-13 set limits on the opacity of the CO-13 J = 1 yields 0 line averaged over the central kiloparsec of these spiral galaxies
Прогнозирование геологической среды земной коры по материалам ГСЗ и петрофизического термобарического исследования минерального вещества
Some features of methodical means of petrovelocity thermobaric modeling have been considered. An example of the construction of a deep petrovelocity model of a crust part of the Ukrainian Shield is given and analysed
Operations on integral lifts of K(n)
This very rough sketch is a sequel to arXiv:1808.08587; it presents evidence
that operations on lifts of the functors K(n) to cohomology theories with
values in modules over valuation rings of local number fields, indexed by
Lubin-Tate groups of such fields, are extensions of the groups of automorphisms
of the indexing group laws, by the exterior algebras on the normal bundle to
the orbits of the group laws in the space of lifts.Comment: \S 2.0 hopefully less cryptic. To appear in the proceedings of the
2015 Nagoya conference honoring T Ohkawa. Comments very welcome
Selection for Lean Growth Rate in a Synthetic Line of YorkshireMeishan Pigs 1. Selection Pressure Applied and Direct Response
Selection for lean growth rate (LGR) was conducted for four generations in a synthetic line of YorkshireMeishan pigs. In the select line, seven boars and 20 gilts with the highest LGR were selected from each generation to produce the subsequent generation. A contemporaneous control line was maintained by randomly selecting five boars and 15 gilts to produce the next generation. Inbreeding coefficients averaged .198 and .207 for the select and control line pigs and .173 and .162 for the select and control line dams, respectively, in the fourth generation. LGR was estimated from ultrasound measures of 10 th -rib backfat thickness and longissimus muscle area from 1,057 pigs. These pigs were sired by 58 boars and out of 133 sows. The generation interval was 13 months and the average selection differential per generation was 1.1 phenotypic standard deviation units for LGR. Heritability and response were estimated from the deviation of select line from the control line and multiple trait derivative free restricted maximum likelihood (MTDFREML) on the same material. Realized heritability was .29 ± .12 for LGR in the control line. Corresponding estimates from MTDFREML were .32 and .37. The estimate of direct genetic change per generation using the deviation from the control line was 9.4 g/day for LGR. Corresponding estimates from MTDFREML were similar but were more precisely estimated
Genetic Parameters for Lean Growth Rate and Its Components in U.S. Landrace Pigs
Records on 65,536 Landrace pigs collected between 1985 and 1999 in herds on the National Swine Registry STAGES program were used to estimate additive genetic (animal), common environmental (litter), and residual variances and covariances for days to 250 lb, backfat, loin eye area, and lean growth rate. Analysis was by the REMLf90 program of I. Misztal using a multiple-trait animal model with fixed effects of contemporary group and sex and random effects of animal, litter, and residual error. Heritability estimates were 0.54, 0.39, 0.49, and 0.48 for days to 250 lb, backfat, loin eye area, and lean growth rate, respectively. Genetic correlations for lean growth rate with days to 250, backfat, and loin eye area were -0.83, -0.38, and 0.40, respectively. Phenotypic correlations for lean growth rate with days to 250 lb, backfat, and loin eye area were -0.80, -0.40, and 0.56, respectively. Litter effects were large only for days to 250 lb. Lean growth rate should be used as an important selection criteria in genetic improvement in pigs
- …