504 research outputs found

    Environmental Impact Assessment: Detecting Changes in Fish Community Structure in Response to Disturbance with an Asymmetric Multivariate BACI Sampling Design

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    One of the primary challenges to detecting anthropogenic environmental impacts is the high degree of spatial and temporal variability inherent in natural systems. Planned or routine events that result in disturbance to populations and communities provide an opportunity for scientists to apply well-replicated and statistically powerful sampling designs to assess subsequent biological effects. For example, a thick layer of sessile invertebrates is the prominent biotic feature of intertidal and shallow subtidal portions of offshore petroleum platforms in southern California. Given the central role of such invertebrates in providing food and shelter, their presence can reasonably be expected to influence associated fish community structure. At one platform on the San Pedro Shelf, invertebrate biomass was completely removed from support pilings and horizontal crossmembers to a depth of 20 m with high-pressure water during a standard “hydrocleaning” event in November 2007. Three nearby platforms remained undisturbed, providing a unique opportunity to test for disturbance-related changes in the local fish assemblage and the overall time course of community recovery. The potential impact of the abrupt and intense removal of the invertebrate layer was assessed with survey data collected periodically for one year prior- and one year post-hydrocleaning in a modified Before-After-Control-Impact (BACI) design. Asymmetrical multivariate analyses of variance revealed a significant effect of disturbance to fish, driven largely by reductions in the abundance of numerically dominant blacksmith (Chromis punctipinnis). Nevertheless, the system was surprisingly resilient, recovering to pre-disturbance conditions within ten months. Our results demonstrate that a well-replicated BACI sampling design can detect even subtle biological changes in response to disturbance, a key step towards developing a mechanistic understanding of community disassembly in the face of increasingly frequent and intense perturbations

    Monitoring Handbook 6: Analyzing and interpreting monitoring data

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    The basic purpose of data analysis is to identify patterns of change in your indicator over time, and to evaluate these changes. Without doing some kind of analysis, it will be difficult for you to know the effect your project is actually having. The data analysis techniques presented in this handbook are not difficult. Most of them can be easily done using little more than a calculator and scratch paper. If necessary, there are resources listed in the handbook for additional assistance analyzing your data

    Monitoring Handbook 4: Monitoring ecological effects

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    The goal of restoration should be to create a self-sustaining ecosystem that functions well and needs little maintenance. Monitoring is essential in order to see if projects are achieving improved ecological conditions. Part 1 of this handbook includes a description of common restoration goals and indicators. Methods for measuring each indicator are described in Part 2

    Monitoring Handbook 1: What is multiparty monitoring?

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    There are many reasons for monitoring your project and using a multiparty approach. Multiparty monitoring will increase your understanding of the effects of restoration actions, support adaptive management, and set a course for future management. Multiparty monitoring also helps build trust among partners and establish project accountability in the broader community. This handbook will guide you through the initial steps required to develop a multiparty monitoring process

    Monitoring Handbook 5: Monitoring social and economic effects of forest restoration

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    Forest restoration projects frequently have social, economic, and cultural goals as well as ecological goals. For instance, project partners may hope that their project will provide new jobs and reduce local unemployment, keep youth in the community, reduce the wildfire risk to human lives and property, or increase public involvement in national forest planning and decision making. Monitoring provides a way to determine whether you are headed toward or away from these goals. For example, your monitoring group might want to ask, Is our community becoming more or less sustainable? Are local management skills improving or getting worse? or Is the use of small-diameter trees increasing or decreasing? Part 1 of this handbook describes indicators that can help community-based multiparty monitoring groups measure changes in common forest restoration project goals. Part 2 describes specific methods for measuring change in each indicator

    The black hole final state

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    We propose that in quantum gravity one needs to impose a final state boundary condition at black hole singularities. This resolves the apparent contradiction between string theory and semiclassical arguments over whether black hole evaporation is unitary.Comment: 17 pages, harvmac, 1 figure, v2: comment about interactions and references adde

    Monitoring Handbook 2: Developing a multiparty monitoring plan.

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    Developing a clear, concise plan for how monitoring will be done is an essential part of any monitoring program. A monitoring plan will help your group make sure that the date you gather are useful and meaningful. It ensures that information is collected at the right time and place and helps to provide transparency, an important part of the multiparty monitoring process. This handbook covers the basic steps in designing a monitoring plan

    Production of asiaticoside and madecasosside in Centella asiatica in vitro and in vivo

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    The localization was determined of the triterpenoids, asiaticoside and madecassoside, in different organs of glasshousegrown plants and cultured material, including transformed roots, of two phenotypes of Centella asiatica (L.) Urban of Malaysian origin. Methanolic extracts of asiaticoside and madecassoside were prepared for gradient HPLC analysis. The two phenotypes of C. asiatica exhibited differences in terpenoid content that were tissue specific and varied between glasshouse-grown plants and tissue culture-derived material. Terpenoid content was highest in leaves, with asiaticoside (0.79 ± 0.03 and 1.15 ± 0.10 % of dry mass) and madecassoside [0.97 ± 0.06 and 1.65 ± 0.01 %(d.m.)] in the fringed (F) and smooth leaf (S) phenotypes, respectively. Roots of the F-phenotype contained the lowest content of asiaticoside [0.12 ± 0.01 %(d.m.)], whereas petioles of S-phenotype plants contained the lowest content of asiaticoside [0.16 ± 0.01 %(d.m.)] and madecassoside [0.18 ± 0.14 %(d.m.)]. Transformed roots were induced using Agrobacterium rhizogens and their growth was maximal on Murashige and Skoog basal medium supplemented with 60 g dm-3 sucrose. However, asiaticoside and madecassoside were undetectable in transformed roots and undifferentiated callus

    Large enhancement of deuteron polarization with frequency modulated microwaves

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    We report a large enhancement of 1.7 in deuteron polarization up to values of 0.6 due to frequency modulation of the polarizing microwaves in a two liters polarized target using the method of dynamic nuclear polarization. This target was used during a deep inelastic polarized muon-deuteron scattering experiment at CERN. Measurements of the electron paramagnetic resonance absorption spectra show that frequency modulation gives rise to additional microwave absorption in the spectral wings. Although these results are not understood theoretically, they may provide a useful testing ground for the deeper understanding of dynamic nuclear polarization.Comment: 10 pages, including the figures coming in uuencoded compressed tar files in poltar.uu, which also brings cernart.sty and crna12.sty files neede
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