2,598 research outputs found

    Horticultural markets promote alien species invasions : an Estonian case study of herbaceous perennials

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    Gardening is a popular pastime, but commercial horticulture is responsible for the introduction of alien species and contributes to invasions in a variety of ways. Although an extensive international literature is available on plant invasions, it is still important at the national level to examine the influence of local factors. Accordingly, 17 nurseries in Estonia that cultivated and sold perennial alien species were selected, and a list of species and prices was compiled. The relationships between species status, and factors such as their abundance in the wild were examined statistically. A qualitative list of the nationally problematic species among herbaceous perennials was also completed. A total of 880 taxa were recorded, of which 10.3% were native and 89.7% alien. In all, 87.3% of the alien species were still confined to cultivated areas. The ecological and socio-economic characteristics of the taxa were described, and lists of the families of casual, naturalised and invasive aliens were provided. Both native and increasing wild alien species have a very similar profile on the market. Alien species that are less expensive, widely available and have more cultivars per species on the market are also more likely to escape. The invasive status and abundance of escaped aliens in an area increases with residence time. In general, socio-economic factors create new and reflect previous propagule pressures from commercial horticulture, which continuously increase the likelihood of alien species surviving and invading new areas. Our findings suggest that these national socioeconomic market-related factors explain much of the invasiveness of various perennial ornamental species, and therefore regional and national authorities urgently need to regulate and control the ornamental plant trade to diminish the risk of new invasions

    Observations of Xyleborus affinis Eichhoff (Coleoptera:Curculionidae:Scolytinae) in Central Michigan

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    Xyleborus affinis Eichhoff colonized wind thrown timber in the moist floodplain habitats of Central Michigan. Single adult females constructed a complex gallery system consisting of phloem–sapwood interface tunnels and sapwood tunnels. An average of 24 progeny adults and a sex ratio of 14 females to 1 male were found in mature galleries after the first of September

    The Brookhaven muon g-2 experiment

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    A hierarchy of compatibility and comeasurability levels in quantum logics with unique conditional probabilities

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    In the quantum mechanical Hilbert space formalism, the probabilistic interpretation is a later ad-hoc add-on, more or less enforced by the experimental evidence, but not motivated by the mathematical model itself. A model involving a clear probabilistic interpretation from the very beginning is provided by the quantum logics with unique conditional probabilities. It includes the projection lattices in von Neumann algebras and here probability conditionalization becomes identical with the state transition of the Lueders - von Neumann measurement process. This motivates the definition of a hierarchy of five compatibility and comeasurability levels in the abstract setting of the quantum logics with unique conditional probabilities. Their meanings are: the absence of quantum interference or influence, the existence of a joint distribution, simultaneous measurability, and the independence of the final state after two successive measurements from the sequential order of these two measurements. A further level means that two elements of the quantum logic (events) belong to the same Boolean subalgebra. In the general case, the five compatibility and comeasurability levels appear to differ, but they all coincide in the common Hilbert space formalism of quantum mechanics, in von Neumann algebras, and in some other cases.Comment: 12 page

    Foundation Design for the Burj Dubai – the World’s Tallest Building

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    This paper describes the foundation design process adopted for the Burj Dubai, the world’s tallest building. The foundation system is a piled raft, founded on deep deposits of carbonate soils and rocks. The paper will outline the geotechnical investigations undertaken, the field and laboratory testing programs, and the design process, and will discuss how various design issues, including cyclic degradation of skin friction due to wind loading, were addressed. The numerical computer analysis that was adopted for the original design together with the check/calibration analyses will be outlined, and then the alternative analysis employed for the peer review process will be described. The paper sets out how the various design issues were addressed, including ultimate capacity, overall stability under wind and seismic loadings, and the settlement and differential settlements. The comprehensive program of pile load testing that was undertaken, which included grouted and non-grouted piles to a maximum load of 64MN, will be presented and “Class A” predictions of the axial load-settlement behaviour will be compared with the measured behavior. The settlements of the towers observed during construction will be compared with those predicted

    Laser induced magnetization switching in films with perpendicular anisotropy: a comparison between measurements and a multi-macrospin model

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    Thermally-assisted ultra-fast magnetization reversal in a DC magnetic field for magnetic multilayer thin films with perpendicular anisotropy has been investigated in the time domain using femtosecond laser heating. The experiment is set-up as an optically pumped stroboscopic Time Resolved Magneto-Optical Kerr Effect magnetometer. It is observed that a modest laser fluence of about 0.3 mJ/square-cm induces switching of the magnetization in an applied field much less than the DC coercivity (0.8 T) on the sub-nanosecond time-scale. This switching was thermally-assisted by the energy from the femtosecond pump-pulse. The experimental results are compared with a model based on the Landau Lifschitz Bloch equation. The comparison supports a description of the reversal process as an ultra-fast demagnetization and partial recovery followed by slower thermally activated switching due to the spin system remaining at an elevated temperature after the heating pulse.Comment: 8 pages, 10 figures, to be submitted to PR

    Ab interno trabecular bypass surgery with Trabectome for open angle glaucoma

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    BACKGROUND: Glaucoma is the leading cause of irreversible blindness. Minimally invasive surgical techniques, such as ab interno trabecular bypass surgery, have been introduced to prevent glaucoma progressing. OBJECTIVES: The main objective was to assess the results at two years of ab interno trabecular bypass surgery with Trabectome for open angle glaucoma in comparison to conventional medical, laser, or surgical treatment in terms of efficacy and safety. A secondary objective was to examine the effects of Trabectome surgery in people who have concomitant phacoemulsification in comparison to those who do not have concomitant phacoemulsification. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2016), EMBASE (January 1980 to May 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 12 May 2016. SELECTION CRITERIA: We included only randomised controlled trials (RCTs) of ab interno trabecular bypass surgery with Trabectome. DATA COLLECTION AND ANALYSIS: We planned to have two review authors independently extract data from reports of included studies using a data collection form. MAIN RESULTS: One randomised controlled trial identified from ClinicalTrials.gov, NCT00901108, met the criteria for inclusion. This study has subsequently been terminated. The ClinicalTrials.gov record indicates that the investigators plan to complete 12 months of follow-up and analysis on 19 participants already recruited into the trial. AUTHORS' CONCLUSIONS: There is currently no high-quality evidence for the outcomes of ab interno trabecular bypass surgery with Trabectome for open angle glaucoma. Properly designed RCTs are needed to assess the long-term efficacy and safety of this technique

    Sodium dependent inositol transport in HL60 cells is not related to Na+/K+, ATPase activity

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    AbstractIn HL60 cells, inositol transport is sodium-dependent but functionally independent of Na+/K+ ATPase activity. This observation has implications for the currently proposed theory for the development of diabetic complications
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