246 research outputs found

    Corn Ethanol Expansion and the Evolution of US Crop Patterns

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    The 2007 expansion of the U.S. Renewable Fuel Standard (the so-called RFS2) has had significant, and controversial, impacts on U.S. agriculture. We combine rich spatial data on observed crop choices with two metrics of corn demand by the ethanol industry to estimate the impact of the RFS2 on crop patterns. Crop choices are observed at the field level using two recent extensions of the Cropland Data Layer database. The time path of the RFS2 mandate captures its corn demand expansion at the aggregate level, and the heterogeneous impact of this biofuel policy across space is measured by a novel local ethanol demand index computed at the field level. This framework permits us to characterize both the local and overall impacts of the RFS2. We find that the ceteris paribus local presence of RFS2-induced ethanol plants, for the 13 Midwest states in the analysis, increased total corn area by 1.6%, increased the area of corn following corn by 4.3%, and had a small, spatially heterogeneous impact on soybeans. Of more consequence is the overall impact of the RFS2, which is estimated to have increased total corn area by 9.7% and corn following corn by 16.8%. Interestingly, total soybean area was also significantly impacted by the RFS2, increasing by 6.7%, and corn-soybean rotations increased by about 10%. These results indicate a major impact of the RFS2 on the geography of corn and soybean cultivation—intensification in the heart of the Corn Belt, and significant expansion near the periphery of the Corn Belt—which included the conversion of 13.9% of land previously used for other crops and/or conservation to corn/soybean production

    Procurement Contracts and Buyer Power: Insights from Hotelling

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    This paper analyzes a Hotelling duopsony model with location-based price discrimination and procurement contracts pegged to the average spot-market price. This setup captures key features of US beef processors’ procurement of cattle supplies, which relies heavily on (controversial) spot-price contracts known as Alternative Marketing Arrangements. We show that use of these contracts increases the equilibrium price markdown in the market; and, as spot-price contracts become more prevalent, the markdown increases at an increasing rate. Both of these conclusions also apply to the standard case of uniform mill pricing.JEL Codes: L13, L66, Q13This research was supported in part by the Economic Research Service, US Department of Agriculture (cooperative agreement No. 58-3000-1-0121). The views expressed in this paper are those of the authors and not necessarily those of the U.S. Department of Agriculture

    Reflecting the past, imag(in)ing the past: macro-reflection imaging of painting materials by fast MIR hyperspectral analysis

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    Imaging spectroscopy has been developed in the last two decades in the visible and infrared spectral range for detecting pigments and binders on paintings. The near-infrared (NIR) region has been proved effective for the discrimination of lipids and proteinaceous binders. More recently, the mid-infrared (MIR) range has also been tested on paintings. Reflection imaging prototypes already developed could be further optimized for cultural heritage analysis, for example by: enhancing the instrument configuration and performance; adopting compressive strategies to increase data processing speeds; using data validation to confirm that the processed image reflects the composition of a painted surface; and lowering price to enable more cost-effective analysis of large surface areas. Here, we demonstrate a novel hyperspectral Fourier transform spectrometer (HS FTS), which enables an imaging strategy that provides a significant improvement in acquisition rate compared to other state-of-the-art techniques. We demonstrate hyperspectral imaging across the 1400–700 cm−1 region in reflection mode with test samples and the painting ‘Uplands in Lorne’ (Acc. No.: GLAHA43427) by D.Y. Cameron (1865–1945). A post-processing analysis of the resulting hyperspectral images, after validation of reference samples by conventional Fourier transform infrared spectroscopy, shows the potential of the method for efficient non-destructive classification of different materials found on painted cultural heritage. This research demonstrates that the HS FTS is a convenient and compact tool for non-invasive analysis of painted cultural heritage objects at spatio-spectral acquisition rates potentially higher than current FTS imaging techniques. Ultimately, when combined with fast graphics processing unit-based reconstruction, the HS FTS may enable fast, large area imaging

    Array comparative genomic hybridisation-based identification of two imbalances of chromosome 1p in a 9-year-old girl with a monosomy 1p36 related phenotype and a family history of learning difficulties: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Monosomy 1p36 is one of the most common terminal deletion syndromes, with an approximate incidence of 1 in every 5000 live births. This syndrome is associated with several pronounced clinical features including characteristic facial features, cardiac abnormalities, seizures and mental retardation, all of which are believed to be due to haploinsufficiency of genes within the 1p36 region. The deletion size varies from approximately 1.5 Mb to 10 Mb with the most common breakpoints located at 1p36.13 to 1p36.33. Over 70% of 1p36 deletion patients have a true terminal deletion. A further 7% have interstitial deletions and a proportion have a derivative chromosome 1 where the 1p telomere is replaced by material from another chromosome, either as a result of a de-novo rearrangement or as a consequence of malsegregation of a balanced parental translocation at meiosis.</p> <p>Case presentation</p> <p>Array comparative genomic hybridisation analysis of a 9-year-old Caucasian girl presenting with dysmorphic facial features and learning difficulties, for whom previous routine karyotyping had been normal, identified two submicroscopic rearrangements within chromosome 1p. Detection of both an insertional duplication of a region of 1p32.3 into the subtelomeric region of the short arm of a chromosome 1 homologue and a deletion within 1p36.32 of the same chromosome instigated a search for candidate genes within these regions which could be responsible for the clinical phenotype of the patient. Several genes were identified by computer-based annotation, some of which have implications in neurological and physical development.</p> <p>Conclusion</p> <p>Array comparative genomic hybridisation is providing a robust method for pinpointing regions of candidate genes associated with clinical phenotypes that extend beyond the resolution of the light microscope. This case report provides an example of how this method of analysis and the subsequent reporting of findings have proven useful in collaborative efforts to elucidate multiple gene functions from a clinical perspective.</p

    Addressing the welfare needs of farmed lumpfish: knowledge gaps, challenges and solutions

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    Lumpfish (Cyclopterus lumpus L.) are increasingly being used as cleaner fish to control parasitic sea lice, one of the most important threats to salmon farming. However, lumpfish cannot survive feeding solely on sea lice, and their mortality in salmon net pens can be high, which has welfare, ethical and economic implications. The industry is under increasing pressure to improve the welfare of lumpfish, but little guidance exists on how this can be achieved. We undertook a knowledge gap and prioritisa tion exercise using a Delphi approach with participants from the fish farming sector, animal welfare, academia and regulators to assess consensus on the main challenges and potential solutions for improving lumpfish welfare. Consensus among participants on the utility of 5 behavioural and 12 physical welfare indicators was high (87–89%), reliable (Cronbach's alpha = 0.79, 95CI = 0.69–0.92) and independent of participant background. Participants highlighted fin erosion and body damage as the most use ful and practical operational welfare indicators, and blood parameters and behav ioural indicators as the least practical. Species profiling revealed profound differences between Atlantic salmon and lumpfish in relation to behaviour, habitat preferences, nutritional needs and response to stress, suggesting that applying a common set of welfare standards to both species cohabiting in salmon net-pens may not work well for lumpfish. Our study offers 16 practical solutions for improving the welfare of lumpfish and illustrates the merits of the Delphi approach for achieving consensus among stakeholders on welfare needs, targeting research where is most needed and generating workable solutions.info:eu-repo/semantics/publishedVersio

    Haematopoietic stem cells do not asymmetrically segregate chromosomes or retain BrdU

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    Stem cells are proposed to segregate chromosomes asymmetrically during self-renewing divisions so that older ('immortal') DNA strands are retained in daughter stem cells whereas newly synthesized strands segregate to differentiating cells(1-6). Stem cells are also proposed to retain DNA labels, such as 5-bromo-2-deoxyuridine (BrdU), either because they segregate chromosomes asymmetrically or because they divide slowly(5,7-9). However, the purity of stem cells among BrdU-label-retaining cells has not been documented in any tissue, and the 'immortal strand hypothesis' has not been tested in a system with definitive stem cell markers. Here we tested these hypotheses in haematopoietic stem cells (HSCs), which can be highly purified using well characterized markers. We administered BrdU to newborn mice, mice treated with cyclophosphamide and granulocyte colony-stimulating factor, and normal adult mice for 4 to 10 days, followed by 70 days without BrdU. In each case, less than 6% of HSCs retained BrdU and less than 0.5% of all BrdU-retaining haematopoietic cells were HSCs, revealing that BrdU has poor specificity and poor sensitivity as an HSC marker. Sequential administration of 5-chloro-2-deoxyuridine and 5-iodo-2-deoxyuridine indicated that all HSCs segregate their chromosomes randomly. Division of individual HSCs in culture revealed no asymmetric segregation of the label. Thus, HSCs cannot be identified on the basis of BrdU-label retention and do not retain older DNA strands during division, indicating that these are not general properties of stem cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62821/1/nature06115.pd

    The positive impact of conservation action

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    Governments recently adopted new global targets to halt and reverse the loss of biodiversity. It is therefore crucial to understand the outcomes of conservation actions. We conducted a global meta-analysis of 186 studies (including 665 trials) that measured biodiversity over time and compared outcomes under conservation action with a suitable counterfactual of no action. We find that in two-thirds of cases, conservation either improved the state of biodiversity or at least slowed declines. Specifically, we find that interventions targeted at species and ecosystems, such as invasive species control, habitat loss reduction and restoration, protected areas, and sustainable management, are highly effective and have large effect sizes. This provides the strongest evidence to date that conservation actions are successful but require transformational scaling up to meet global targets

    LSST Science Book, Version 2.0

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    A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo
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