2,125 research outputs found

    The small business assistance dilemma: is the disparity between the offerings of support agencies and the needs of business irreconcilable?

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    There is a wide range of service providers who have varying motives for supplying assistance to small businesses in Australia. Despite the sizeable numbers of both suppliers and consumers of assistance it is believed that the marketplace for small business assistance operates inefficiently. This inefficiency is described as a disparity or misfit between the learning opportunities offered by service providers to small business and the learning needs of small business owner / operators. This paper provides an analysis of the learning activity that currently exists in the small enterprise sector. The role of communication in bringing supply and demand closer together is discussed and a proposition is developed to alleviate the learning disparity via a more proactive approach to communication by service providers. Two small enterprise projects are used to test the proposition. The findings provide guidance for the more effective functioning of organisations that serve and support small businesses

    Integrating cavity based gas cells: a multibeam compensation scheme for pathlength variation

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    We present a four beam ratiometric setup for an integrating sphere based gas cell, which can correct for changes in pathlength due to sphere wall contamination. This allows for the gas absorption coefficient to be determined continuously without needing to recalibrate the setup. We demonstrate the technique experimentally, measuring methane gas at 1651nm. For example, contamination covering 1.2% of the sphere wall resulted in an uncompensated error in gas absorption coefficient of ≈41%. With the ratiometric scheme, this error was reduced to ≈2%. Potential limitations of the technique, due to subsequent deviations from mathematical assumptions are discussed, including severe sphere window contamination

    Using Chemistry to Unveil the Kinematics of Starless Cores: Complex Radial Motions in Barnard 68

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    We present observations of 13CO, C18O, HCO+, H13CO+, DCO+ and N2H+ line emission towards the Barnard 68 starless core. The line profiles are interpreted using a chemical network coupled with a radiative transfer code in order to reconstruct the radial velocity profile of the core. Our observations and modeling indicate the presence of complex radial motions, with the inward motions in the outer layers of the core but outward motions in the inner part, suggesting radial oscillations. The presence of such oscillation would imply that B68 is relatively old, typically one order of magnitude older than the age inferred from its chemical evolution and statistical core lifetimes. Our study demonstrates that chemistry can be used as a tool to constrain the radial velocity profiles of starless cores.Comment: 12 pages, 3 figures, to appear in the Astrophysical Journal Letter

    Molecule sublimation as a tracer of protostellar accretion: Evidence for accretion bursts from high angular resolution C18O images

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    The accretion histories of embedded protostars are an integral part of descriptions of their physical and chemical evolution. In particular, are the accretion rates smoothly declining from the earlier toward later stages or in fact characterized by variations such as intermittent bursts? We aim to characterize the impact of possible accretion variations in a sample of embedded protostars by measuring the size of the inner regions of their envelopes where CO is sublimated and relate those to their temperature profiles dictated by their current luminosities. Using observations from the Submillimeter Array we measure the extents of the emission from the C18O isotopologue toward 16 deeply embedded protostars. We compare these measurements to the predicted extent of the emission given the current luminosities of the sources through dust and line radiative transfer calculations. Eight out of sixteen sources show more extended C18O emission than predicted by the models. The modeling shows that the likely culprit for these signatures is sublimation due to increases in luminosities of the sources by about a factor five or more during the recent 10,000 years - the time it takes for CO to freeze-out again on dust grains. For four of those sources the increase would have had to have been a factor 10 or more. The compact emission seen toward the other half of the sample suggests that C18O only sublimates when the temperature exceeds 30 K - as one would expect if CO is mixed with H2O in the grain ice-mantles. The small-number statistics from this survey suggest that protostars undergo significant bursts about once every 20,000 years. This also illustrates the importance of taking the physical evolutionary histories into account for descriptions of the chemical structures of embedded protostars.Comment: Accepted by A&A; 11 pages, 5 figure

    Atomic jet from SMM1 (FIRS1) in Serpens uncovers non-coeval binary companion

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    We report on the detection of an atomic jet associated with the protostellar source SMM1 (FIRS1) in Serpens. The jet is revealed in [FeII] and [NeII] line maps observed with Spitzer/IRS, and further confirmed in HiRes IRAC and MIPS images. It is traced very close to SMM1 and peaks at ~5 arcsec" from the source at a position angle of $\sim 125 degrees. In contrast, molecular hydrogen emission becomes prominent at distances > 5" from the protostar and extends at a position angle of 160 degrees. The morphological differences suggest that the atomic emission arises from a companion source, lying in the foreground of the envelope surrounding the embedded protostar SMM1. In addition the molecular and atomic Spitzer maps disentangle the large scale CO (3-2) emission observed in the region into two distinct bipolar outflows, giving further support to a proto-binary source setup. Analysis at the peaks of the [FeII] jet show that emission arises from warm and dense gas (T ~1000 K, n(electron) 10^5 - 10^6 cm^-3). The mass flux of the jet derived independently for the [FeII] and [NeII] lines is 10^7 M(sun)/yr, pointing to a more evolved Class~I/II protostar as the driving source. All existing evidence converge to the conclusion that SMM1 is a non-coeval proto-binary source.Comment: 10 pages, 7 figures, 1 table. Accepted for publication in Astronomy \& Astrophysic

    Beyond Competitive Devaluations: The Monetary Dimensions of Comparative Advantage

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    Motivated by the long-standing debate on the pros and cons of competitive devaluation, we propose a new perspective on how monetary and exchange rate policies can contribute to a country's international competitiveness. We refocus the analysis on the implications of monetary stabilization for a country's comparative advantage. We develop a two-country New-Keynesian model allowing for two tradable sectors in each country: while one sector is perfectly competitive,firms in the other sector produce differentiated goods under monopolistic competition subject to sunk entry costs and nominal rigidities, hence their performance is more sensitive to macroeconomic uncertainty. We show that, by stabilizing markups, monetary policy can foster the competitiveness of these firms, encouraging investment and entry in the differentiated goods sector, and ultimately affecting the composition of domestic output and exports. Panel regressions based on worldwide exports to the U.S. by sector lend empirical support to the theory.Constraining monetary policy with an exchange rate peg lowers a country's share of differentiated goods in exports between 4 and 12 percent

    Control of light transmission through opaque scattering media in space and time

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    We report the first experimental demonstration of combined spatial and temporal control of light trajectories through opaque media. This control is achieved by solely manipulating spatial degrees of freedom of the incident wavefront. As an application, we demonstrate that the present approach is capable to form bandwidth-limited ultrashort pulses from the otherwise randomly transmitted light with a controllable interaction time of the pulses with the medium. Our approach provides a new tool for fundamental studies of light propagation in complex media and has potential for applications for coherent control, sensing and imaging in nano- and biophotonics
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