1,082 research outputs found
Dust heating by the interstellar radiation field in models of turbulent molecular clouds
We have calculated the radiation field, dust grain temperatures, and far
infrared emissivity of numerical models of turbulent molecular clouds. When
compared to a uniform cloud of the same mean optical depth, most of the volume
inside the turbulent cloud is brighter, but most of the mass is darker. There
is little mean attenuation from center to edge, and clumping causes the
radiation field to be somewhat bluer. There is also a large dispersion,
typically by a few orders of magnitude, of all quantities relative to their
means. However, despite the scatter, the 850 micron emission maps are well
correlated with surface density. The fraction of mass as a function of
intensity can be reproduced by a simple hierarchical model of density
structure.Comment: 32 pages, 14 figures, submitted to Ap
Statistical Assessment of Shapes and Magnetic Field Orientations in Molecular Clouds through Polarization Observations
We present a novel statistical analysis aimed at deriving the intrinsic
shapes and magnetic field orientations of molecular clouds using dust emission
and polarization observations by the Hertz polarimeter. Our observables are the
aspect ratio of the projected plane-of-the-sky cloud image, and the angle
between the mean direction of the plane-of-the-sky component of the magnetic
field and the short axis of the cloud image. To overcome projection effects due
to the unknown orientation of the line-of-sight, we combine observations from
24 clouds, assuming that line-of-sight orientations are random and all are
equally probable. Through a weighted least-squares analysis, we find that the
best-fit intrinsic cloud shape describing our sample is an oblate disk with
only small degrees of triaxiality. The best-fit intrinsic magnetic field
orientation is close to the direction of the shortest cloud axis, with small
(~24 deg) deviations toward the long/middle cloud axes. However, due to the
small number of observed clouds, the power of our analysis to reject
alternative configurations is limited.Comment: 14 pages, 8 figures, accepted for publication in MNRA
Міжнародна наукова конференція "Архівознавство як наука"
Проаналізовано внесок істориків і архівістів України в розвиток архівної науки. Вказуються основні розділи архівознавства як науки, що вимагають подальших досліджень.Проанализирован вклад историков и архивистов Украины в развитие архивной науки. Указываются основные разделы архивоведения как науки, которые требуют дальнейших исследований.A contribution of Ukrainian historians and archivists to the archival science development is covered. The basic sections of the archival science which need the further study are indicated
A “How-To” Guide for Designing Judgment Bias Studies to Assess Captive Animal Welfare
Robust methods to assess nonhuman animal emotion are essential for ensuring good welfare in captivity. Cognitive bias measures such as the judgment bias task have recently emerged as promising tools to assess animal emotion. The simple design and objective response measures make judgment bias tasks suitable for use across species and contexts. In reviewing 64 studies published to date, it emerged that (a) judgment biases have been measured in a number of mammals and birds and an invertebrate; (b) no study has tested judgment bias in any species of fish, amphibian, or reptile; and (c) no study has yet investigated judgment bias in a zoo or aquarium. This article proposes that judgment bias measures are highly suitable for use with these understudied taxa and can provide new insight into welfare in endangered species housed in zoos and aquariums, where poor welfare impacts breeding success and, ultimately, species survival. The article includes a “how-to” guide to designing judgment bias tests with recommendations for working with currently neglected “exotics” including fishes, amphibians, and reptiles
Chemical evolution of turbulent protoplanetary disks and the Solar nebula
This is the second paper in a series where we study the influence of
transport processes on the chemical evolution of protoplanetary disks. Our
analysis is based on a flared alpha-model of the DM Tau system, coupled to a
large gas-grain chemical network. To account for production of complex
molecules, the chemical network is supplied with an extended set of surface
reactions and photo-processes in ice mantles. Our disk model covers a wide
range of radii, 10-800 AU (from a Jovian planet-forming zone to the outer disk
edge). Turbulent transport of gases and ices is implicitly modeled in full 2D
along with the time-dependent chemistry. Two regimes are considered, with high
and low efficiency of turbulent mixing. The results of the chemical model with
suppressed turbulent diffusion are close to those from the laminar model, but
not completely. A simple analysis for the laminar chemical model to highlight
potential sensitivity of a molecule to transport processes is performed. It is
shown that the higher the ratio of the characteristic chemical timescale to the
turbulent transport timescale for a given molecule, the higher the probability
that its column density will be affected by diffusion. We find that turbulent
transport enhances abundances and column densities of many gas-phase species
and ices, particularly, complex ones. For such species a chemical steady-state
is not reached due to long timescales associated with evaporation and surface
photoprocessing and recombination. In contrast, simple radicals and molecular
ions, which chemical evolution is fast and proceeds solely in the gas phase,
are not much affected by dynamics. All molecules are divided into three groups
according to the sensitivity of their column densities to the turbulent
diffusion. [Abridged]Comment: 42 pages, 13 figures, 16 tables, accepted for publication in ApJS
Evaluation of in vitro cross-reactivity to avian H5N1 and pandemic H1N1 2009 influenza following prime boost regimens of seasonal influenza vaccination in healthy human subjects: A randomised trial
published_or_final_versio
TREATMENT OF LEUKEMIA AND RELATED DISORDERS WITH 6-MERCAPTOPURINE
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74802/1/j.1749-6632.1954.tb40034.x.pd
Transformations in the law concerning slavery: legacies of the nineteenth century anti-slavery movement
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