2,955 research outputs found
Distortions to Agricultural Incentives in Australia and New Zealand
In 1990, Australia and New Zealand were ranked around 25th and 35th in terms of GNP per capita, having been the highest-income countries in the world one hundred years earlier. The poor performance over that long period contrasts markedly with that of the past 15 years, when these two economies out-performed most other high-income countries. This difference in growth performance is due to major economic policy reforms during the past two to three decades. We provide new evidence on the extent of governmental distortions to agricultural incentives in particular in the two economies since the late 1940s, both directly and indirectly (and negatively) via manufacturing protection.Distorted incentives, agricultural and trade policy reform, Agricultural and Food Policy, F13, F14, Q17, Q18,
Factors associated with the efficacy of polyp detection during routine flexible sigmoidoscopy
Objective: Flexible sigmoidoscopy reduces the incidence of colonic cancer through the detection and removal of premalignant adenomas. However, the efficacy of the procedure is variable. The aim of the present study was to examine factors associated with the efficacy of detecting polyps during flexible sigmoidoscopy.
Design and patients: Retrospective observational cohort study of all individuals undergoing routine flexible sigmoidoscopy in NHS Greater Glasgow and Clyde from January 2013 to January 2016.
Results: A total of 7713 patients were included. Median age was 52 years and 50% were male. Polyps were detected in 1172 (13%) patients. On multivariate analysis, increasing age (OR 1.020 (1.016–1.023) p<0.001), male sex (OR 1.23 (1.10–1.38) p<0.001) and the use of any bowel preparation (OR 3.55 (1.47–8.57) p<0.001) were associated with increasing numbers of polyps being detected. There was no significant difference in the number of polyps found in patients who had received an oral laxative preparation compared with an enema (OR 3.81 (1.57–9.22) vs 3.45 (1.43–8.34)), or in those who received sedation versus those who had not (OR 1.00 vs 1.04 (0.91–1.17) p=0.591). Furthermore, the highest number of polyps was found when the sigmoidoscope was inserted to the descending colon (OR 1.30 (1.04–1.63)).
Conclusions: Increasing age, male sex and the utilisation of any bowel preparation were associated with an increased polyp detection rate. However, the use of sedation or oral laxative preparation appears to confer no additional benefit. In addition, the results indicate that insertion to the descending colon optimises the efficacy of flexible sigmoidoscopy polyp detection
General Report Session No. 7: Case Histories of Soil Improvement, Grouting, Geosynthetics, Dynamic Compaction, Vibroflotation, Blasting, and Other Methods
Exploratory Chandra Observations of the Three Highest Redshift Quasars Known
We report on exploratory Chandra observations of the three highest redshift
quasars known (z = 5.82, 5.99, and 6.28), all found in the Sloan Digital Sky
Survey. These data, combined with a previous XMM-Newton observation of a z =
5.74 quasar, form a complete set of color-selected, z > 5.7 quasars. X-ray
emission is detected from all of the quasars at levels that indicate that the
X-ray to optical flux ratios of z ~ 6 optically selected quasars are similar to
those of lower redshift quasars. The observations demonstrate that it will be
feasible to obtain quality X-ray spectra of z ~ 6 quasars with current and
future X-ray missions.Comment: 15 pages, ApJL, in press; small revisions to address referee Comment
Alexandrium fundyense cyst viability and germling survival in light vs. dark at a constant low temperature
Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 103 (2014): 112–119, doi:10.1016/j.dsr2.2013.05.010.Both observations and models suggest that large-scale coastal blooms of Alexandrium fundyense in the
Gulf of Maine are seeded by deep-bottom cyst accumulation zones (“seed beds”) where cysts
germinate from the sediment surface or the overlying near-bottom nepheloid layers at water depths
exceeding 100 m. The germling cells and their vegetative progeny are assumed to be subject to modest
mortality while in complete darkness as they swim to illuminated surface waters. To test the validity of
this assumption we investigated in the laboratory cyst viability and the survival of the germling cells
and their vegetative progeny during prolonged exposure to darkness at a temperature of 6°C,
simulating the conditions in deep Gulf of Maine waters. We isolated cysts from bottom sediments
collected in the Gulf of Maine under low red light and incubated them in 96-well tissue culture-plates
in culture medium under a 10:14h light: dark cycle and under complete darkness. Cyst viability was
high, with excystment frequency reaching 90% in the illuminated treatment after 30 days and in the
dark treatment after 50 days. Average germination rates were 0.062 and 0.038 d-1 for light and dark
treatments, respectively. The dark treatment showed an approximately two-week time lag in maximum
germination rates when compared to the light treatment. Survival of germlings was considerably lower
in the dark treatment. In light treatments, 47% of germinated cysts produced germlings that were able to survive for 7 days and produce vegetative progeny, i.e. there were live cells in the well along with an
empty cyst at least once during the experiment. In the dark treatments 12% of cysts produced germlings
that were able to survive. When dark treatments are scaled to take into account non-darkness related
mortality, approximately 28% of cysts produced germlings that were able to survive for at least 7 days.
Even though cysts are able to germinate in darkness, the lack of illumination considerably reduces
survival rate of germling cells. In addition to viability of cysts in surface sediments and the near-bottom
nepheloid layer, survivability of germling cells and their vegetative progeny at aphotic depths is an
important consideration in assessing the quantitative role of deep-coastal cyst seed beds in bloom
formation.E. Vahtera was funded by the Academy of Finland (grant #130934) and B. Gomez-Crespo was
supported by a Xunta de Galicia Ángeles Alvariño fellowship. Additional funding support was also
provided by the National Oceanic Atmospheric Administration ECOHAB program through grants
NA06NOS4780245 and NA09NOS4780193 and from National Science Foundation grants OCE-
0430724 and OCE-0911031 and National Institute of Environmental Health Sciences grant 1P50-
ES01274201 through the Woods Hole Center for Oceans and Human Health
Alexandrium fundyense cyst viability and germling survival in light vs. dark at a constant low temperature
Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 103 (2014): 112–119, doi:10.1016/j.dsr2.2013.05.010.Both observations and models suggest that large-scale coastal blooms of Alexandrium fundyense in the
Gulf of Maine are seeded by deep-bottom cyst accumulation zones (“seed beds”) where cysts
germinate from the sediment surface or the overlying near-bottom nepheloid layers at water depths
exceeding 100 m. The germling cells and their vegetative progeny are assumed to be subject to modest
mortality while in complete darkness as they swim to illuminated surface waters. To test the validity of
this assumption we investigated in the laboratory cyst viability and the survival of the germling cells
and their vegetative progeny during prolonged exposure to darkness at a temperature of 6°C,
simulating the conditions in deep Gulf of Maine waters. We isolated cysts from bottom sediments
collected in the Gulf of Maine under low red light and incubated them in 96-well tissue culture-plates
in culture medium under a 10:14h light: dark cycle and under complete darkness. Cyst viability was
high, with excystment frequency reaching 90% in the illuminated treatment after 30 days and in the
dark treatment after 50 days. Average germination rates were 0.062 and 0.038 d-1 for light and dark
treatments, respectively. The dark treatment showed an approximately two-week time lag in maximum
germination rates when compared to the light treatment. Survival of germlings was considerably lower
in the dark treatment. In light treatments, 47% of germinated cysts produced germlings that were able to survive for 7 days and produce vegetative progeny, i.e. there were live cells in the well along with an
empty cyst at least once during the experiment. In the dark treatments 12% of cysts produced germlings
that were able to survive. When dark treatments are scaled to take into account non-darkness related
mortality, approximately 28% of cysts produced germlings that were able to survive for at least 7 days.
Even though cysts are able to germinate in darkness, the lack of illumination considerably reduces
survival rate of germling cells. In addition to viability of cysts in surface sediments and the near-bottom
nepheloid layer, survivability of germling cells and their vegetative progeny at aphotic depths is an
important consideration in assessing the quantitative role of deep-coastal cyst seed beds in bloom
formation.E. Vahtera was funded by the Academy of Finland (grant #130934) and B. Gomez-Crespo was
supported by a Xunta de Galicia Ángeles Alvariño fellowship. Additional funding support was also
provided by the National Oceanic Atmospheric Administration ECOHAB program through grants
NA06NOS4780245 and NA09NOS4780193 and from National Science Foundation grants OCE-
0430724 and OCE-0911031 and National Institute of Environmental Health Sciences grant 1P50-
ES01274201 through the Woods Hole Center for Oceans and Human Health
General Report — Session 5: Stability and Displacement Performance of Slopes, Landfills, and Earth Dams Under Earthquakes
Spectral Energy Distributions and Multiwavelength Selection of Type 1 Quasars
We present an analysis of the mid-infrared (MIR) and optical properties of type 1 (broad-line) quasars detected by the Spitzer Space Telescope. The MIR color-redshift relation is characterized to z ~ 3, with predictions to z = 7. We demonstrate how combining MIR and optical colors can yield even more efficient selection of active galactic nuclei (AGNs) than MIR or optical colors alone. Composite spectral energy distributions (SEDs) are constructed for 259 quasars with both Sloan Digital Sky Survey and Spitzer photometry, supplemented by near-IR, GALEX, VLA, and ROSAT data, where available. We discuss how the spectral diversity of quasars influences the determination of bolometric luminosities and accretion rates; assuming the mean SED can lead to errors as large as 50% for individual quasars when inferring a bolometric luminosity from an optical luminosity. Finally, we show that careful consideration of the shape of the mean quasar SED and its redshift dependence leads to a lower estimate of the fraction of reddened/obscured AGNs missed by optical surveys as compared to estimates derived from a single mean MIR to optical flux ratio
Efficient Photometric Selection of Quasars from the Sloan Digital Sky Survey: 100,000 z<3 Quasars from Data Release One
We present a catalog of 100,563 unresolved, UV-excess (UVX) quasar candidates
to g=21 from 2099 deg^2 of the Sloan Digital Sky Survey (SDSS) Data Release One
(DR1) imaging data. Existing spectra of 22,737 sources reveals that 22,191
(97.6%) are quasars; accounting for the magnitude dependence of this
efficiency, we estimate that 95,502 (95.0%) of the objects in the catalog are
quasars. Such a high efficiency is unprecedented in broad-band surveys of
quasars. This ``proof-of-concept'' sample is designed to be maximally
efficient, but still has 94.7% completeness to unresolved, g<~19.5, UVX quasars
from the DR1 quasar catalog. This efficient and complete selection is the
result of our application of a probability density type analysis to training
sets that describe the 4-D color distribution of stars and spectroscopically
confirmed quasars in the SDSS. Specifically, we use a non-parametric Bayesian
classification, based on kernel density estimation, to parameterize the color
distribution of astronomical sources -- allowing for fast and robust
classification. We further supplement the catalog by providing photometric
redshifts and matches to FIRST/VLA, ROSAT, and USNO-B sources. Future work
needed to extend the this selection algorithm to larger redshifts, fainter
magnitudes, and resolved sources is discussed. Finally, we examine some science
applications of the catalog, particularly a tentative quasar number counts
distribution covering the largest range in magnitude (14.2<g<21.0) ever made
within the framework of a single quasar survey.Comment: 35 pages, 11 figures (3 color), 2 tables, accepted by ApJS; higher
resolution paper and ASCII version of catalog available at
http://sdss.ncsa.uiuc.edu/qso/nbckde
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