306 research outputs found

    The difference in blood pressure readings between arms and survival: primary care cohort study

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    Objective To determine whether a difference in systolic blood pressure readings between arms can predict a reduced event free survival after 10 years

    Paying the pipers: mitigating the impact of anticoagulant rodenticides on predators and scavengers

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    Anticoagulant rodenticides, mainly second-generation forms, or SGARs, dominate the global market for rodent control. Introduced in the 1970s to counter genetic resistance in rodent populations to first-generation compounds such as warfarin, SGARs are extremely toxic and highly effective killers. However, their tendency to persist and accumulate in the body has led to the widespread contamination of terrestrial predators and scavengers. Commercial chemicals that are classified by regulators as persistent, bio-accumulative, and toxic (PBT) chemicals and that are widely used with potential environmental release, such as dichloro-diphenyl-trichloroethane (DDT) or polychlorinated biphenyls (PCBs), have been removed from commerce. However, despite consistently failing ecological risk assessments, SGARs remain in use because of the demand for effective rodent-control options and the lack of safe and humane alternatives. Although new risk-mitigation measures for rodenticides are now in effect in some countries, the contamination and poisoning of nontarget wildlife are expected to continue. Here, we suggest options to further attenuate this problem

    Adverse outcome pathway and risks of anticoagulant rodenticides to predatory wildlife

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    Despite a long history of successful use, routine application of some anticoagulant rodenticides (ARs) may be at a crossroad due to new regulatory guidelines intended to mitigate risk. An adverse outcome pathway for ARs was developed to identify information gaps and end points to assess the effectiveness of regulations. This framework describes chemical properties of ARs, established macromolecular interactions by inhibition of vitamin K epoxide reductase, cellular responses including altered clotting factor processing and coagulopathy, organ level effects such as hemorrhage, organism responses with linkages to reduced fitness and mortality, and potential consequences to predator populations. Risk assessments have led to restrictions affecting use of some second-generation ARs (SGARs) in North America. While the European regulatory community highlighted significant or unacceptable risk of ARs to nontarget wildlife, use of SGARs in most EU member states remains authorized due to public health concerns and the absence of safe alternatives. For purposes of conservation and restoration of island habitats, SGARs remain a mainstay for eradication of invasive species. There are significant data gaps related to exposure pathways, comparative species sensitivity, consequences of sublethal effects, potential hazards of greater AR residues in genetically resistant prey, effects of low-level exposure to multiple rodenticides, and quantitative data on the magnitude of nontarget wildlife mortality

    Crossover Scaling Functions in One Dimensional Dynamic Growth Models

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    The crossover from Edwards-Wilkinson (s=0s=0) to KPZ (s>0s>0) type growth is studied for the BCSOS model. We calculate the exact numerical values for the k=0k=0 and 2π/N2\pi/N massgap for N18N\leq 18 using the master equation. We predict the structure of the crossover scaling function and confirm numerically that m04(π/N)2[1+3u2(s)N/(2π2)]0.5m_0\simeq 4 (\pi/N)^2 [1+3u^2(s) N/(2\pi^2)]^{0.5} and m12(π/N)2[1+u2(s)N/π2]0.5m_1\simeq 2 (\pi/N)^2 [1+ u^2(s) N/\pi^2]^{0.5}, with u(1)=1.03596967u(1)=1.03596967. KPZ type growth is equivalent to a phase transition in meso-scopic metallic rings where attractive interactions destroy the persistent current; and to endpoints of facet-ridges in equilibrium crystal shapes.Comment: 11 pages, TeX, figures upon reques

    New Symmetries of Supersymmetric Effective Lagrangians

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    We consider the structure of effective lagrangians describing the low-energy dynamics of supersymmetric theories in which a global symmetry GG is spontaneously broken to a subgroup HH while supersymmetry is unbroken. In accordance with the supersymmetric Goldstone theorem, these lagrangians contain Nambu--Goldstone superfields associated with a coset space Gc/H^G^c / \hat{H}, where GcG^c is the complexification of GG and H^\hat{H} is the largest subgroup of GcG^c that leaves the order parameter invariant. The lagrangian may also contain additional light matter fields. To analyze the effective lagrangian for the matter fields, we first consider the case where the effective lagrangian is obtained by integrating out heavy modes at weak coupling (but including non-perturbative effects such as instantons). We show that the superpotential of the matter fields is H^\hat{H} invariant, which can give rise to non-trivial relations among independent HH-invariants in the superpotential. We also show that the Kahler potential of the matter fields can be restricted by a remnant of H^\hat{H} symmetry. These results are non-perturbative and have a simple group-theoretic interpretation. When we relax the weak-coupling constraint, there appear to be additional possibilities for the action of H^\hat{H} on the matter fields, hinting that the constraints imposed by H^\hat{H} may be even richer in strongly coupled theories.Comment: 23 pages, plain Te

    Use of terrestrial field studies in the derivation of bioaccumulation potential of chemicals

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    Field-based studies are an essential component of research addressing the behavior of organic chemicals, and a unique line of evidence that can be used to assess bioaccumulation potential in chemical registration programs and aid in development of associated laboratory and modeling efforts. To aid scientific and regulatory discourse on the application of terrestrial field data in this manner, this article provides practical recommendations regarding the generation and interpretation of terrestrial field data. Currently, biota-to-soil-accumulation factors (BSAFs), biomagnification factors (BMFs), and bioaccumulation factors (BAFs) are the most suitable bioaccumulation metrics that are applicable to bioaccumulation assessment evaluations and able to be generated from terrestrial field studies with relatively low uncertainty. Biomagnification factors calculated from field-collected samples of terrestrial carnivores and their prey appear to be particularly robust indicators of bioaccumulation potential. The use of stable isotope ratios for quantification of trophic relationships in terrestrial ecosystems needs to be further developed to resolve uncertainties associated with the calculation of terrestrial trophic magnification factors (TMFs). Sampling efforts for terrestrial field studies should strive for efficiency, and advice on optimization of study sample sizes, practical considerations for obtaining samples, selection of tissues for analysis, and data interpretation is provided. Although there is still much to be learned regarding terrestrial bioaccumulation, these recommendations provide some initial guidance to the present application of terrestrial field data as a line of evidence in the assessment of chemical bioaccumulation potential and a resource to inform laboratory and modeling efforts

    The influence of density of modes on dark lines in spontaneous emission

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    We study two distinct multi-level atomic models in which one transition is coupled to a Markovian reservoir, while another linked transition is coupled to a non-Markovian reservoir. We show that by choosing appropriately the density of modes of the non-Markovian reservoir the spontaneous emission to the Markovian reservoir is greatly altered. The existence of `dark lines' in the spontaneous emission spectrum in the Markovian reservoir due to the coupling to specific density of modes of the non-Markovian reservoir is also predicted.Comment: 11 pages including 9 figure
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