4,821 research outputs found
Exports, Technical Progress and Productivity Growth in Chinese Manufacturing Industries
Theories suggesting either static or dynamic productivity gains derived from exports often assume the prior existence of a perfect market. In the presence of market failure, however, the competition effect and the resource reallocation effect of exports on productive efficiency may be greatly reduced; and there may actually be disincentives for innovation. This paper analyses the impact of exports on total factor productivity (TFP) growth in a transition economy using a panel of Chinese manufacturing industries over the period 1990-1997. TFP growth is estimated by employing a non-parametric approach and is decomposed into technical progress and efficiency change. We have not found evidence suggesting significant productivity gains at the industry level resulting from exports. Findings of the current study suggest that, for exports to generate significant positive effect on TFP growth, a well?developed domestic market and a neutral, outward-oriented policy are necessary.exports, industrial efficiency, technical progress, productivity
An Early Bronze Age 'dagger grave' from Rameldry Farm, near Kingskettle, Fife
In February 2000, ploughing disturbed the capstone of a cist, located on the side of a prominent knowe at Rameldry Farm, near Kingskettle in central Fife. Excavation by Headland Archaeology Ltd on behalf of Historic Scotland revealed a short cist which contained the crouched inhumation of a man aged 40-50, who had suffered from arthritis, some tooth loss and possibly Paget's Disease. He had been buried wearing a garment adorned with six V-pelforated buttons. Five of these are of Whitby jet (including one with unique decoration including inlaid tin); the sixth is of the mineral lizardite, and has an enigmatic coating, possibly a glaze. Behind his shoulder was a dagger, of 'Milston type (East Kennet variant) it had had a fancy horn hilt and a scabbard lined with animal skin. The scabbard yielded two A MS radiocarbon dates, with a mean value of 2280-1970 cal Bc at 2
The Number Density of Intermediate and High Luminosity Active Galactic Nuclei at z~2-3
We use the combination of the 2 Ms Chandra X-ray image, new J and H band
images, and the Spitzer IRAC and MIPS images of the Chandra Deep Field-North to
obtain high spectroscopic and photometric redshift completeness of high and
intermediate X-ray luminosity sources in the redshift interval z=2-3. We
measure the number densities of z=2-3 active galactic nuclei (AGNs) and
broad-line AGNs in the rest-frame 2-8 keV luminosity intervals 10^44-10^45 and
10^43-10^44 ergs/s and compare with previous lower redshift results. We confirm
a decline in the number densities of intermediate-luminosity sources at z>1. We
also measure the number density of z=2-3 AGNs in the luminosity interval
10^43-10^44.5 ergs/s and compare with previous low and high-redshift results.
Again, we find a decline in the number densities at z>1. In both cases, we can
rule out the hypothesis that the number densities remain flat to z=2-3 at above
the 5-sigma level.Comment: 8 pages, Accepted by The Astrophysical Journal (scheduled for 10 Dec
2005
Spitzer Observations of Gamma-Ray Burst Host Galaxies: A Unique Window into High Redshift Chemical Evolution and Star-formation
We present deep Spitzer 3.6 micron observations of three z~5 GRB host
galaxies. Our observations reveal that z~5 GRB hosts are a factor of 3 less
luminous than the median rest-frame V-band luminosity of spectroscopically
confirmed z~5 galaxies in the GOODS fields and the UDF. The strong connection
between GRBs and massive star formation implies that not all star-forming
galaxies at these redshifts are currently being accounted for in deep surveys
and GRBs provide a unique way to measure the contribution to the star-formation
rate density from galaxies at the faint end of the galaxy luminosity function.
By correlating the co-moving star-formation rate density with co-moving GRB
rates at lower redshifts, we estimate a lower limit to the star-formation rate
density of 0.12+/-0.09 and 0.09+/-0.05 M_sun/yr/Mpc^3 at z~4.5 and z~6,
respectively. Finally, we provide evidence that the average metallicity of
star-forming galaxies evolves as (stellar mass density)^(0.69+/-0.17) between
and , probably indicative of the loss of a significant
fraction of metals to the intergalactic medium, particularly in low-mass
galaxies.Comment: ApJ, in pres
Potential synergies between existing multilateral environmental agreements in the implementation of Land Use, Land Use Change and Forestry activities
There is potential for synergy between the global environmental conventions on climate change, biodiversity and desertification: changes in land management and land use undertaken to reduce net greenhouse gas emissions can simultaneously deliver positive outcomes for conservation of biodiversity, and mitigation of desertification and land degradation. However, while there can be complementarities between the three environmental goals, there are often tradeoffs. Thus, the challenge lies in developing land use policies that promote optimal environmental outcomes, and in implementing these locally to promote sustainable development. The paper considers synergies and tradeoffs in implementing land use measures to address the objectives of the three global environmental conventions, both from an environmental and economic perspective. The intention is to provide environmental scientists and policy makers with a broad overview of these considerations, and the benefits of addressing the conventions simultaneously.Climate change, LULUCF, Biodiversity, Desertification, Sustainable development.
Detection of Massive Forming Galaxies at Redshifts Greater than One
The complex problem of when and how galaxies formed has not until recently
been susceptible of direct attack. It has been known for some time that the
excessive number of blue galaxies counted at faint magnitudes implies that a
considerable fraction of the massive star formation in the universe occurred at
z < 3, but, surprisingly, spectroscopic studies of galaxies down to a B
magnitude of 24 found little sign of the expected high-z progenitors of current
massive galaxies, but rather, in large part, small blue galaxies at modest
redshifts z \sim 0.3. This unexpected population has diverted attention from
the possibility that early massive star-forming galaxies might also be found in
the faint blue excess. From KECK spectroscopic observations deep enough to
encompass a large population of z > 1 field galaxies, we can now show directly
that in fact these forming galaxies are present in substantial numbers at B
\sim 24, and that the era from redshifts 1 to 2 was clearly a major period of
galaxy formation. These z > 1 galaxies have very unusual morphologies as seen
in deep HST WFPC2 images.Comment: 10 pages LaTeX + 5 PostScript figures in uuencoded gzipped tar file;
aasms4.sty, flushrt.sty, overcite.sty (the two aastex4.0 and overcite.sty
macros are available from xxx.lanl.gov) Also available (along with style
files) via anonymous ftp to ftp://hubble.ifa.hawaii.edu/pub/preprints .
E-print version of paper adds citation cross-references to other archived
e-prints, where available. To appear in Nature October 19, 199
A Flux-Limited Sample of z~1 Ly-alpha Emitting Galaxies in the CDFS
We describe a method for obtaining a flux-limited sample of Ly-alpha emitters
from GALEX grism data. We show that the multiple GALEX grism images can be
converted into a three-dimensional (two spatial axes and one wavelength axis)
data cube. The wavelength slices may then be treated as narrowband images and
searched for emission-line galaxies. For the GALEX NUV grism data, the method
provides a Ly-alpha flux-limited sample over the redshift range z=0.67-1.16. We
test the method on the Chandra Deep Field South field, where we find 28
Ly-alpha emitters with faint continuum magnitudes (NUV>22) that are not present
in the GALEX pipeline sample. We measure the completeness by adding artificial
emitters and measuring the fraction recovered. We find that we have an 80%
completeness above a Ly-alpha flux of 10^-15 erg/cm^2/s. We use the UV spectra
and the available X-ray data and optical spectra to estimate the fraction of
active galactic nuclei in the selection. We report the first detection of a
giant Ly-alpha blob at z<1, though we find that these objects are much less
common at z=1 than at z=3. Finally, we compute limits on the z~1 Ly-alpha
luminosity function and confirm that there is a dramatic evolution in the
luminosity function over the redshift range z=0-1.Comment: 18 pages, in press at The Astrophysical Journa
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