26,652 research outputs found

    Russian manufacturing and the threat of ‘Dutch disease’: a comparison of competitiveness developments in Russian and Ukrainian industry

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    This paper examines the development of Russian industry in comparison with that of Ukrainian industry during 1995–2004 in an effort to ascertain to what extent, if any, Russian manufacturing showed signs of succumbing to ‘Dutch disease’. Ukraine and Russia began the market transition with broadly similar institutions, industrial structures and levels of technology, and the economic reforms implemented in the two countries were also similar, although Ukraine was reckoned to lag behind Russia in many areas. The main difference between them is Russia’s far greater resource wealth. It follows that differences in industrial development since 1991 may to some degree be attributable to differences in initial natural resource endowments. In short, Ukraine could provide a rough approximation of how a resource-poor Russia might have developed over the transition

    Vacuum field energy and spontaneous emission in anomalously dispersive cavities

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    Anomalously dispersive cavities, particularly white light cavities, may have larger bandwidth to finesse ratios than their normally dispersive counterparts. Partly for this reason, their use has been proposed for use in LIGO-like gravity wave detectors and in ring-laser gyroscopes. In this paper we analyze the quantum noise associated with anomalously dispersive cavity modes. The vacuum field energy associated with a particular cavity mode is proportional to the cavity-averaged group velocity of that mode. For anomalously dispersive cavities with group index values between 1 and 0, this means that the total vacuum field energy associated with a particular cavity mode must exceed ω/2\hbar \omega/2. For white light cavities in particular, the group index approaches zero and the vacuum field energy of a particular spatial mode may be significantly enhanced. We predict enhanced spontaneous emission rates into anomalously dispersive cavity modes and broadened laser linewidths when the linewidth of intracavity emitters is broader than the cavity linewidth.Comment: 9 pages, 4 figure

    Estimation of the methane emission factor for the Italian Mediterranean buffalo

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    In order to contribute to the improvement of the national greenhouse gas emission inventory, this work aimed at estimating a country-specific enteric methane (CH4) emission factor for the Italian Mediterranean buffalo. For this purpose, national agriculture statistics, and information on animal production and farming conditions were analysed, and the emission factor was estimated using the Tier 2 model of the Intergovernmental Panel on Climate Change. Country-specific CH4 emission factors for buffalo cows (630 kg body weight, BW) and other buffalo (313 kg BW) categories were estimated for the period 1990–2004. In 2004, the estimated enteric CH4 emission factor for the buffalo cows was 73 kg/head per year, whereas that for other buffalo categories it was 56 kg/head per year. Research in order to determine specific CH4 conversion rates at the predominant production system is suggested

    Investigating the Relation between Galaxy Properties and the Gaussianity of the Velocity Distribution of Groups and Clusters

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    We investigate the dependence of stellar population properties of galaxies on group dynamical stage for a subsample of Yang catalog. We classify groups according to their galaxy velocity distribution into Gaussian (G) and Non-Gaussian (NG). Using two totally independent approaches we have shown that our measurement of Gaussianity is robust and reliable. Our sample covers Yang's groups in the redshift range 0.03 \leq z \leq 0.1 having mass \geq 1014M^{14} \rm M_{\odot}. The new method, Hellinger Distance (HD), to determine whether a group has a velocity distribution Gaussian or Non-Gaussian is very effective in distinguishing between the two families. NG groups present halo masses higher than the G ones, confirming previous findings. Examining the Skewness and Kurtosis of the velocity distribution of G and NG groups, we find that faint galaxies in NG groups are mainly infalling for the first time into the groups. We show that considering only faint galaxies in the outskirts, those in NG groups are older and more metal rich than the ones in G groups. Also, examining the Projected Phase Space of cluster galaxies we see that bright and faint galactic systems in G groups are in dynamical equilibrium which does not seem to be the case in NG groups. These findings suggest that NG systems have a higher infall rate, assembling more galaxies which experienced preprocessing before entering the group.Comment: 55 pages, 5 Tables and 12 Figures. Accepted for publication in Astronomical Journa

    Complexity analysis of Klein-Gordon single-particle systems

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    The Fisher-Shannon complexity is used to quantitatively estimate the contribution of relativistic effects to on the internal disorder of Klein-Gordon single-particle Coulomb systems which is manifest in the rich variety of three-dimensional geometries of its corresponding quantum-mechanical probability density. It is observed that, contrary to the non-relativistic case, the Fisher-Shannon complexity of these relativistic systems does depend on the potential strength (nuclear charge). This is numerically illustrated for pionic atoms. Moreover, its variation with the quantum numbers (n, l, m) is analysed in various ground and excited states. It is found that the relativistic effects enhance when n and/or l are decreasing.Comment: 4 pages, 3 figures, Accepted in EPL (Europhysics Letters

    Star formation in the giant HII regions of M101

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    The molecular components of three giant HII regions (NGC 5461, NGC 5462, NGC 5471) in the galaxy M101 are investigated with new observations from the James Clerk Maxwell Telescope, the NRAO 12-meter, and the Owens Valley millimeter array. Of the three HII regions, only NGC 5461 had previously been detected in CO emission. We calculate preliminary values for the molecular mass of the GMCs in NGC 5461 by assuming a CO-to-H_2 factor (X factor) and then compare these values with the virial masses. We conclude that the data in this paper demonstrate for the first time that the value of X may decrease in regions with intense star formation. The molecular mass for the association of clouds in NGC 5461 is approximately 3x10^7 Mo and is accompanied by 1-2 times as much atomic mass. The observed CO emission in NGC 5461 is an order of magnitude stronger than in NGC 5462, while it was not possible to detect molecular gas toward NGC 5471 with the JCMT. An even larger ratio of atomic to molecular gas in NGC 5471 was observed, which might be attributed to efficient conversion of molecular to atomic gas. The masses of the individual clouds in NGC 5461, which are gravitationally bound, cover a range of (2-8) x 10^5 Mo, comparable with the masses of Galactic giant molecular clouds (GMCs). Higher star forming efficiencies, and not massive clouds, appear to be the prerequisite for the formation of the large number of stars whose radiation is required to produce the giant HII regions in M101.Comment: 32 pages, 5 figures, accepted for publication in the Astrophysical Journa

    Structural anisotropy and orientation-induced Casimir repulsion in fluids

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    In this work we theoretically consider the Casimir force between two periodic arrays of nanowires (both in vacuum, and on a substrate separated by a fluid) at separations comparable to the period. Specifically, we compute the dependence of the exact Casimir force between the arrays under both lateral translations and rotations. Although typically the force between such structures is well-characterized by the Proximity Force Approximation (PFA), we find that in the present case the microstructure modulates the force in a way qualitatively inconsistent with PFA. We find instead that effective-medium theory, in which the slabs are treated as homogeneous, anisotropic dielectrics, gives a surprisingly accurate picture of the force, down to separations of half the period. This includes a situation for identical, fluid-separated slabs in which the exact force changes sign with the orientation of the wire arrays, whereas PFA predicts attraction. We discuss the possibility of detecting these effects in experiments, concluding that this effect is strong enough to make detection possible in the near future.Comment: 12 pages, 9, figure. Published version with expanded discussio

    Sub-au imaging of water vapour clouds around four Asymptotic Giant Branch stars

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    We present MERLIN maps of the 22-GHz H2O masers around four low-mass late-type stars (IK Tau U Ori, RT Vir and U Her), made with an angular resolution of ~ 15 milliarcsec and a velocity resolution of 0.1 km s-1. The H2O masers are found in thick expanding shells with inner radii ~ 6 to 16 au and outer radii four times larger. The expansion velocity increases radially through the H2O maser regions, with logarithmic velocity gradients of 0.5--0.9. IK Tau and RT Vir have well-filled H2O maser shells with a spatial offset between the near and far sides of the shell, which suggests that the masers are distributed in oblate spheroids inclined to the line of sight. U Ori and U Her have elongated poorly-filled shells with indications that the masers at the inner edge have been compressed by shocks; these stars also show OH maser flares. MERLIN resolves individual maser clouds, which have diameters of 2 -- 4 au and filling factors of only ~ 0.01 with respect to the whole H2O maser shells. The CSE velocity structure gives additional evidence the maser clouds are density bounded. Masing clouds can be identified over a similar timescale to their sound crossing time (~2 yr) but not longer. The sizes and observed lifetimes of these clouds are an order of magnitude smaller than those around red supergiants, similar to the ratio of low-mass:high-mass stellar masses and sizes. This suggests that cloud size is determined by stellar properties, not local physical phenomena in the wind.Comment: 21 pages, including 14 figures and 8 tables. Accepted for publication in MNRA
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