123 research outputs found
Evolution of the Structure and Thermodynamic Stability of the BaTiO\u3csub\u3e3\u3c/sub\u3e(001) Surface
We report a series of new surface reconstructions on BaTiO3(001) as a function of environmental conditions, determined via scanning tunneling microscopy and low energy electron diffraction. Using density functional theory calculations and thermodynamic modeling, we construct a surface phase diagram and determine the atomic structures of the thermodynamically stable phases. Excellent agreement is found between the predicted phase diagram and experiment. The results enable prediction of surface structures and properties under the entire range of accessible environmental conditions
The HII region G35.673-00.847: another case of triggered star formation?
As part of a systematic study that we are performing with the aim to increase
the observational evidence of triggered star formation in the surroundings of
HII regions, we analyze the ISM around the HII region G35.673-00.847, a poorly
studied source. Using data from large-scale surveys: Two Micron All Sky Survey,
Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE), MIPSGAL,
Galactic Ring Survey (GRS), VLA Galactic Plane Survey (VGPS), and NRAO VLA Sky
Survey (NVSS) we performed a multiwavelength study of G35.673-00.847 and its
surroundings. The mid IR emission, shows that G35.673-00.847 has an almost
semi-ring like shape with a cut towards the galactic west. The radius of this
semi-ring is about 1.5' (~1.6 pc, at the distance of ~3.7 kpc). The distance
was estimated from an HI absorption study and from the analysis of the
molecular gas. Indeed, we find a molecular shell composed by several clumps
distributed around the HII region, suggesting that its expansion is collecting
the surrounding material. We find several YSO candidates over the molecular
shell. Finally, comparing the HII region dynamical age and the fragmentation
time of the molecular shell, we discard the collect and collapse as the
mechanism responsible for the YSOs formation, suggesting other processes such
as radiative driven implosion and/or small-scale Jeans gravitational
instabilities.Comment: Accepted for publication in A&A, 18 October 2010. Some figures were
degraded to reduce file siz
Features of Social and Economic Support of the Territorial Subjects of the Russian Federation
The political, social and economic reforms of the 90-ies of the last century, along with the activation of such social phenomena as alcoholism, drug addiction, depopulation, etc., gave rise to some processes fundamentally new for Russia - poverty, unemployment, child neglect, forced migration characterized by steady growth of population in need of social support. All these phenomena have identified urgent need to develop a system of measures on social support of the population of Russia, mitigation of negative social consequences of economic reforms. However, the relaxation role the state's role, formation of market mechanisms in the absence of the effective system of social process management in the situation of economic slack, realistic lack of consistency of social policy measures not only failed to alleviate the existing social risks, but often contributed to their increase. The most significant social problems today, despite some improvement in the standard of living of the past few years, are increasing polarization of incomes, the natural decline in population and its marginalization. The social support system existing in contemporary Russia largely corresponds to the socialist mode of management; it is not adapted to the current social and economic factors and conditions of development of Russia.
Keywords: economical good, social and economic support, country population
JEL Classifications: H50, H53, L81, L84, M3
The RMS Survey: 13CO observations of candidate massive YSOs in the southern hemisphere
Abridged: The Red MSX Source (RMS) survey is an ongoing multi-wavelength
observational programme designed to return a large, well-selected sample of
massive young stellar objects (MYSOs). Here we present 13CO observations made
towards 854 MYSOs candidates located in the 3rd and 4th quadrants. We detected
13CO emission towards a total of 751 of the 854 RMS sources observed (~88%). In
total 2185 emission components are detected above 3 level. Multiple
emission profiles are observed towards the majority of these sources - 455
sources (~60%) - with an average of ~4 molecular clouds along the line of
sight. These multiple emission features make it difficult to assign a kinematic
velocity to many of our sample. We have used archival CS (J=2-1) and maser
velocities to resolved the component multiplicity towards 82 sources and have
derived a criterion which is used to identify the most likely component for a
further 202 multiple component sources. Combined with the single component
detections we have obtained unambiguous kinematic velocities towards 580
sources (~80% of the detections). The 171 sources for which we have not been
able to determine the kinematic velocity will require additional line data.
Using the rotation curve of Brand and Blitz (1993) and their radial velocities
we calculate kinematic distances for all components detected.Comment: Summitted to A&A, the resolution of figure 1 has been reduced,
samples of Table 3 and Figure 11 are now included but the full version will
only be available in the online version of the journa
Functioning of Innovative Territorial Clusters
One of the basic directions of development of modern economy, closely related, primarily, to the innovative nature of this development is in the process of forming clusters. Regional and interregional clusters are considered as a priority inter-sectoral complexes that determine the development of post-industrial information economy at the national and regional level. Their development is associated with the processes of globalization and formation of the industrial structure of the information economy. The tasks of Russia's transition to innovative type of development are associated in particular with the need of formation of innovative clusters. Clusters as a form of spatial associations of enterprises is widespread in the Western economies. Taking into account the necessity of innovative development of Russia in the context of improving the competitiveness of industries and sectors in terms of integration of the country into the global economy, we consider it appropriate in this work to conduct a study of foreign experience of formation of clusters (Cherenkov, 2013). From the definition given by the founder of the modern theory of clusters by M. porter, that “...a cluster or industrial group, is a group of geographically neighboring interconnected companies and related organizations operating in a certain area, characterized by common activities and complementary to each other”.
Keywords: cluster, territorial-production cluster, globalization, innovation
JEL Classifications: P25, P28, R1, R1
Absolute positions of 6.7-GHz methanol masers
The ATCA, MERLIN and VLA interferometers were used to measure the absolute
positions of 35 6.7 GHz methanol masers to subarcsecond or higher accuracy. Our
measurements represent essential preparatory data for Very Long Baseline
Interferometry, which can provide accurate parallax and proper motion
determinations of the star-forming regions harboring the masers. Our data also
allow associations to be established with infrared sources at different
wavelengths. Our findings support the view that the 6.7 GHz masers are
associated with the earliest phases of high-mass star formation.Comment: A&A accepted 29 pages, 6 figures, 5 table
Ptch2/Gas1 and Ptch1/Boc differentially regulate Hedgehog signalling in murine primordial germ cell migration.
Gas1 and Boc/Cdon act as co-receptors in the vertebrate Hedgehog signalling pathway, but the nature of their interaction with the primary Ptch1/2 receptors remains unclear. Here we demonstrate, using primordial germ cell migration in mouse as a developmental model, that specific hetero-complexes of Ptch2/Gas1 and Ptch1/Boc mediate the process of Smo de-repression with different kinetics, through distinct modes of Hedgehog ligand reception. Moreover, Ptch2-mediated Hedgehog signalling induces the phosphorylation of Creb and Src proteins in parallel to Gli induction, identifying a previously unknown Ptch2-specific signal pathway. We propose that although Ptch1 and Ptch2 functionally overlap in the sequestration of Smo, the spatiotemporal expression of Boc and Gas1 may determine the outcome of Hedgehog signalling through compartmentalisation and modulation of Smo-downstream signalling. Our study identifies the existence of a divergent Hedgehog signal pathway mediated by Ptch2 and provides a mechanism for differential interpretation of Hedgehog signalling in the germ cell niche
Diffuse Gamma Rays: Galactic and Extragalactic Diffuse Emission
"Diffuse" gamma rays consist of several components: truly diffuse emission
from the interstellar medium, the extragalactic background, whose origin is not
firmly established yet, and the contribution from unresolved and faint Galactic
point sources. One approach to unravel these components is to study the diffuse
emission from the interstellar medium, which traces the interactions of high
energy particles with interstellar gas and radiation fields. Because of its
origin such emission is potentially able to reveal much about the sources and
propagation of cosmic rays. The extragalactic background, if reliably
determined, can be used in cosmological and blazar studies. Studying the
derived "average" spectrum of faint Galactic sources may be able to give a clue
to the nature of the emitting objects.Comment: 32 pages, 28 figures, kapproc.cls. Chapter to the book "Cosmic
Gamma-Ray Sources," to be published by Kluwer ASSL Series, Edited by K. S.
Cheng and G. E. Romero. More details can be found at
http://www.gamma.mpe-garching.mpg.de/~aws/aws.htm
MALT90 Kinematic Distances to Dense Molecular Clumps
Using molecular-line data from the Millimetre Astronomy Legacy Team 90 GHz Survey (MALT90), we have estimated kinematic distances to 1905 molecular clumps identified in the ATLASGAL 870 μm continuum survey over the longitude range 295° < l < 350°. The clump velocities were determined using a flux-weighted average of the velocities obtained from Gaussian fits to the HCO+, HNC, and N2H+ (1–0) transitions. The near/far kinematic distance ambiguity was addressed by searching for the presence or absence of absorption or self-absorption features in 21 cm atomic hydrogen spectra from the Southern Galactic Plane Survey. Our algorithm provides an estimation of the reliability of the ambiguity resolution. The Galactic distribution of the clumps indicates positions where the clumps are bunched together, and these locations probably trace the locations of spiral arms. Several clumps fall at the predicted location of the far side of the Scutum–Centaurus arm. Moreover, a number of clumps with positive radial velocities are unambiguously located on the far side of the Milky Way at galactocentric radii beyond the solar circle. The measurement of these kinematic distances, in combination with continuum or molecular-line data, now enables the determination of fundamental parameters such as mass, size, and luminosity for each clump
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