170 research outputs found

    Product Liability - Real Property Improvements - Statute of Repose

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    The Supreme Court of Pennsylvania held that manufacturers of defective products that are incorporated by others into improvements to real property are not protected from liability pursuant to the Pennsylvania Statute of Repose. McConnaughey v. Building Components, Inc., 637 A.2d 1331 (Pa. 1994)

    The Frequency of Barred Spiral Galaxies in the Near-IR

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    We have determined the fraction of barred galaxies in the H-band for a statistically well-defined sample of 186 spirals drawn from the Ohio State University Bright Spiral Galaxy survey. We find 56% of our sample to be strongly barred at H, while another 16% is weakly barred. Only 27% of our sample is unbarred in the near-infrared. The RC3 and the Carnegie Atlas of Galaxies both classify only about 30% of our sample as strongly barred. Thus strong bars are nearly twice as prevalent in the near-infrared as in the optical. The frequency of genuine optically hidden bars is significant, but lower than many claims in the literature: 40% of the galaxies in our sample that are classified as unbarred in the RC3 show evidence for a bar in the H-band, while for the Carnegie Atlas this fraction is 66%. Our data reveal no significant trend in bar fraction as a function of morphology in either the optical or H-band. Optical surveys of high redshift galaxies may be strongly biased against finding bars, as bars are increasingly difficult to detect at bluer rest wavelengths.Comment: LaTeX with AASTeX style file, 23 pages with 6 figures. Accepted for publication in The Astronomical Journal (Feb. 2000

    Knots in Charged Polymers

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    The interplay of topological constraints and Coulomb interactions in static and dynamic properties of charged polymers is investigated by numerical simulations and scaling arguments. In the absence of screening, the long-range interaction localizes irreducible topological constraints into tight molecular knots, while composite constraints are factored and separated. Even when the forces are screened, tight knots may survive as local (or even global) equilibria, as long as the overall rigidity of the polymer is dominated by the Coulomb interactions. As entanglements involving tight knots are not easy to eliminate, their presence greatly influences the relaxation times of the system. In particular, we find that tight knots in open polymers are removed by diffusion along the chain, rather than by opening up. The knot diffusion coefficient actually decreases with its charge density, and for highly charged polymers the knot's position appears frozen.Comment: Revtex4, 9 pages, 9 eps figure

    Equilibrium shapes of flat knots

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    We study the equilibrium shapes of prime and composite knots confined to two dimensions. Using rigorous scaling arguments we show that, due to self-avoiding effects, the topological details of prime knots are localised on a small portion of the larger ring polymer. Within this region, the original knot configuration can assume a hierarchy of contracted shapes, the dominating one given by just one small loop. This hierarchy is investigated in detail for the flat trefoil knot, and corroborated by Monte Carlo simulations.Comment: 4 pages, 3 figure

    Effects of Replanting and Retention of Mature Oil Palm Riparian Buffers on Ecosystem Functioning in Oil Palm Plantations

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    Oil palm plantations are a major agricultural land use in Southeast Asia. In the coming decades large areas of mature oil palm will be cleared and replanted. To inform more sustainable long-term production in this globally important crop, it is crucial we understand how replanting impacts ecosystem functions and services. We investigated whether several production-relevant ecosystems functions (dung removal, soil mesofauna feeding activity, herbivory, herbivore predation, and seed predation), and the simultaneous delivery of all functions (ecosystem multifunctionality), vary between recently-replanted oil palm (1–4 years) and mature oil palm (23–30 years) areas. Following new in-country and Roundtable on Sustainable Palm Oil (RSPO) guidelines, riparian buffers of mature oil palm, in which subsequent natural regrowth is allowed, are being preserved during the replanting cycle in plantations that lack natural forest reserves. We investigated whether or not mature oil palm riparian buffers maintain levels of ecosystem functioning beneficial for palm oil production. Only one function (herbivory) differed between mature and replanted areas, with higher levels of herbivory found in recently replanted oil palm. There was no difference in ecosystem multifunctionality between mature and recently-replanted oil palm. Mature oil palm riparian buffers were found to be valuable for maintaining lower levels of herbivory than recently-replanted oil palm. However, no other functions, nor ecosystem multifunctionality, differed between the mature oil palm riparian buffers and recently-replanted oil palm. The results of this study suggest that replanting has limited impacts on the ecosystem functions we considered. Furthermore, they suggest mature oil palm riparian buffers do not have negative impacts on production-relevant ecosystem functions in oil palm landscapes.This project was made possible through funding from SMARTRI; the UK Natural Environment Research Council (NERC), the Heron-Allen Travel Scholarship, Lady Margaret Hall; and the University of Oxford Zoology Department. ES was funded under UK Natural Environment Research Council grant (NE/K016407/1). The BEFTA Programme was funded by The Isaac Newton Trust Cambridge, Golden-Agri Resources, and the UK Natural Environment Research Council grant (NE/P00458X/1)

    A framework to measure the properties of intergalactic metal systems with two-point flux statistics

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    The abundance, temperature, and clustering of metals in the intergalactic medium are important parameters for understanding their cosmic evolution and quantifying their impact on cosmological analysis with the Ly α\alpha forest. The properties of these systems are typically measured from individual quasar spectra redward of the quasar's Ly α\alpha emission line, yet that approach may provide biased results due to selection effects. We present an alternative approach to measure these properties in an unbiased manner with the two-point statistics commonly employed to quantify large-scale structure. Our model treats the observed flux of a large sample of quasar spectra as a continuous field and describes the one-dimensional, two-point statistics of this field with three parameters per ion: the abundance (column density distribution), temperature (Doppler parameter) and clustering (cloud-cloud correlation function). We demonstrate this approach on multiple ions (e.g., C IV, Si IV, Mg II) with early data from the Dark Energy Spectroscopic Instrument (DESI) and high-resolution spectra from the literature. Our initial results show some evidence that the C IV abundance is higher than previous measurements and evidence for abundance evolution over time. The first full year of DESI observations will have over an order of magnitude more quasar spectra than this study. In a future paper we will use those data to measure the growth of clustering and its impact on the Ly α\alpha forest, as well as test other DESI analysis infrastructure such as the pipeline noise estimates and the resolution matrix.Comment: 15 pages, 14 figure

    Heterogeneity of genomic evolution and mutational profiles in multiple myeloma.

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    Multiple myeloma is an incurable plasma cell malignancy with a complex and incompletely understood molecular pathogenesis. Here we use whole-exome sequencing, copy-number profiling and cytogenetics to analyse 84 myeloma samples. Most cases have a complex subclonal structure and show clusters of subclonal variants, including subclonal driver mutations. Serial sampling reveals diverse patterns of clonal evolution, including linear evolution, differential clonal response and branching evolution. Diverse processes contribute to the mutational repertoire, including kataegis and somatic hypermutation, and their relative contribution changes over time. We find heterogeneity of mutational spectrum across samples, with few recurrent genes. We identify new candidate genes, including truncations of SP140, LTB, ROBO1 and clustered missense mutations in EGR1. The myeloma genome is heterogeneous across the cohort, and exhibits diversity in clonal admixture and in dynamics of evolution, which may impact prognostic stratification, therapeutic approaches and assessment of disease response to treatment

    Genomic surveillance uncovers a pandemic clonal lineage of the wheat blast fungus

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    Wheat, one of the most important food crops, is threatened by a blast disease pandemic. Here, we show that a clonal lineage of the wheat blast fungus recently spread to Asia and Africa following two independent introductions from South America. Through a combination of genome analyses and laboratory experiments, we show that the decade-old blast pandemic lineage can be controlled by the Rmg8 disease resistance gene and is sensitive to strobilurin fungicides. However, we also highlight the potential of the pandemic clone to evolve fungicide-insensitive variants and sexually recombine with African lineages. This underscores the urgent need for genomic surveillance to track and mitigate the spread of wheat blast outside of South America and to guide preemptive wheat breeding for blast resistance

    Seismic risk assessment for developing countries : Pakistan as a case study

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    Modern Earthquake Risk Assessment (ERA) methods usually require seismo-tectonic information for Probabilistic Seismic Hazard Assessment (PSHA) that may not be readily available in developing countries. To bypass this drawback, this paper presents a practical event-based PSHA method that uses instrumental seismicity, available historical seismicity, as well as limited information on geology and tectonic setting. Historical seismicity is integrated with instrumental seismicity to determine the long-term hazard. The tectonic setting is included by assigning seismic source zones associated with known major faults. Monte Carlo simulations are used to generate earthquake catalogues with randomized key hazard parameters. A case study region in Pakistan is selected to demonstrate the effectiveness of the method. The results indicate that the proposed method produces seismic hazard maps consistent with previous studies, thus being suitable for generating such maps in regions where limited data are available. The PSHA procedure is developed as an integral part of an ERA framework named EQRAM. The framework is also used to determine seismic risk in terms of annual losses for the study region
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