2,468 research outputs found

    Review: Powdery Scab of Potato—Increased Knowledge of Pathogen Biology and Disease Epidemiology for Effective Disease Management

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    The importance of the potato tuber disease powdery scab, caused by the zoosporic pathogen Spongospora subterranea f. sp. subterranea, has increased worldwide, and the disease is one of the most important problems facing potato production in some regions. This soilborne pathogen produces many resting spores which can remain dormant for long periods, are highly resistant to environmental stresses and can spread the disease on seed potatoes and in contaminated soil. The enigmatic nature of this organism exacerbates the development of effective powdery scab control methods. Substantial knowledge has been gained in the last decade on the biology of the pathogen and the epidemiology of the disease, but no single effective control measure is, or is likely to be, available. An integrated approach to powdery scab management is the aim, with host resistance as a substantial and sustainable component. Further research on the epidemiology of powdery scab and population genetics of the pathogen is urgently required. All stakeholders involved in the potato industry must become aware that solution of the powdery scab problem is likely to be a long-term goal. When resistant cultivars with all the other characteristics demanded for marketing high-quality potatoes are available, and when disease risk from the pathogen on seed and/or in soil can be accurately determined, then the mission to develop effective powdery scab control will become achievabl

    Creating Online Brand Value through Online Discussion Site

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    This paper discusses the implications of the new evolving Service-Dominant (S-D) logic in marketing on brand value creation. Furthermore, it introduces the concept of online brand value and examines whether online discussion sites constitute a means for firms to co-create, together with a firm\u27s customers, online brand value. Moreover, a conceptual framework of online discussion sites is proposed. Finally, the results of an exploratory empirical analysis of two discussion sites are presented. The findings provide initial support for the hypothesis that online discussion sites can be used to create online brand value. Moreover, the findings suggest that firm-generated discussion sites are better suited for online brand value co-creation activities than third-party generated discussion sites

    Improved immunological detection of S pongospora subterranea

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    The genus Spongospora has two members which are important pathogens of vegetables, S. subterranea f.sp. subterranea (Sss) and S. subterranea f.sp. nasturtii (Ssn). The close taxonomic relationship of these formae speciales is based on similar cystosori morphology. The potato disease powdery scab, caused by Sss, is difficult to control. The key control measure is avoidance, aimed at planting clean seed in clean soil. For the development of routine tests for the presence of the pathogen on tubers and in soil, a monoclonal antibody (MAb) was developed using Sss cystosori as immunogen. It detected less than one Sss cystosorus and recognised Sss material from many parts of the world. No cross-reactions with other Plasmodiophoromycetes including Plasmodiophora brassicae, Polymyxa betae, Polymyxa graminis and different Streptomyces species causing common and netted scab of potatoes were observed. A novel tuber sample test method was developed using a kitchen peeling machine. This detected two tubers with one powdery scab lesion each in a sample including eighteen uninfected tubers. When soil samples spiked with cystosori were tested with the MAb, different Sss infestation levels could be discriminated. Ssn cystosori gave absorbance values in ELISA as high as Sss cystosori, whereas fresh crook roots of watercress containing Ssnzoosporangia and plasmodia or mud from an Ssninfected watercress bed gave low absorbance values or no reaction. The potential of these findings for the development of a disease control management are discusse

    Resource use and outcome in critically ill patients with hematological malignancy: a retrospective cohort study

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    INTRODUCTION: The paucity of data on resource use in critically ill patients with hematological malignancy and on these patients' perceived poor outcome can lead to uncertainty over the extent to which intensive care treatment is appropriate. The aim of the present study was to assess the amount of intensive care resources needed for, and the effect of treatment of, hemato-oncological patients in the intensive care unit (ICU) in comparison with a nononcological patient population with a similar degree of organ dysfunction. METHODS: A retrospective cohort study of 101 ICU admissions of 84 consecutive hemato-oncological patients and 3,808 ICU admissions of 3,478 nononcological patients over a period of 4 years was performed. RESULTS: As assessed by Therapeutic Intervention Scoring System points, resource use was higher in hemato-oncological patients than in nononcological patients (median (interquartile range), 214 (102 to 642) versus 95 (54 to 224), P < 0.0001). Severity of disease at ICU admission was a less important predictor of ICU resource use than necessity for specific treatment modalities. Hemato-oncological patients and nononcological patients with similar admission Simplified Acute Physiology Score scores had the same ICU mortality. In hemato-oncological patients, improvement of organ function within the first 48 hours of the ICU stay was the best predictor of 28-day survival. CONCLUSION: The presence of a hemato-oncological disease per se is associated with higher ICU resource use, but not with increased mortality. If withdrawal of treatment is considered, this decision should not be based on admission parameters but rather on the evolutional changes in organ dysfunctions

    How to identify groundwater-caused thermal anomalies in lakes based on multi-temporal satellite data in semi-arid regions

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    The deduction by conventional means of qualitative and quantitative information about groundwater discharge into lakes is complicated. Nevertheless, at least for semi-arid regions with limited surface water availability, this information is crucial to ensure future water availability for drinking and irrigation purposes. <br><br> Overcoming this lack of discharge information, we present a satellite-based multi-temporal sea-surface-temperature (SST) approach. It exploits the occurrence of thermal anomalies to outline groundwater discharge locations using the example of the Dead Sea. Based on a set of 19 Landsat Enhanced Thematic Mapper (ETM+) images 6.2 (high gain), recorded between 2000 and 2002, we developed a novel approach which includes (i) an objective exclusion of surface-runoff-influenced data which would otherwise lead to erroneous results and (ii) a temporal SST variability analysis based on six statistical measures amplifying thermal anomalies caused by groundwater. <br><br> After excluding data influenced by surface runoff, we concluded that spatial anomaly patterns of the standard deviation and range of the SST data series spatially fit best to in situ observed discharge locations and, hence, are most suitable for detecting groundwater discharge sites

    In vitro optical quality measurements of three intraocular lens models having identical platform

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    Background: With recent advances in technology and introduction of new intraocular lens (IOL) models, surgeons today have the opportunity to choose from various optical designs, which can influence the postoperative quality of vision. In our laboratory study, we compared the optical quality of three different IOLs that use the identical platform and are produced by the same manufacturer. The study included two diffractive multifocal IOLs, a bifocal and a trifocal one, as well as a monofocal IOL. Methods: Three IOL models: monofocal CT ASPHINA 409 M, diffractive bifocal AT LISA 809 M, and diffractive trifocal AT LISA Tri 839MP (Carl Zeiss Meditec AG, Germany) were assessed for optical quality by measuring modulation transfer function (MTF) and Strehl Ratio (SR) values at pupil sizes of 3.0 and 4.5 mm on the OptiSpheric® IOL PRO (Trioptics GmbH, Germany). The United States Air Force (USAF) Target images were also recorded to comfirm the optical performance qualitatively. Results: For far focus at 50 lp/mm and 3.0 mm pupil size, MTF value of the monofocal lens (MTF = 0.798) was 1.8-fold and 2.1-fold better than the bifocal (MTF = 0.446) and the trifocal (MTF = 0.382) IOLs, respectively. For near focus, bifocal IOL (MTF = 0.265) was 1.4-fold better than trifocal IOL (MTF = 0.187), while for intermediate focus, the trifocal IOL (MTF = 0.148) was 1.7-fold better than the bifocal IOL (MTF = 0.086). For the same pupil size, total sum of light loss amounted to 5.2% for the monofocal, 16.0% for the bifocal and 6.0% for the trifocal IOL. For a larger pupil, the amount of light loss increased significantly for the multifocal IOLs. Conclusions: The monofocal IOL performed the best for far, the bifocal IOL for near and the trifocal IOL for intermediate focus. While the monofocal IOL created the least amount of light loss for both pupil sizes, the trifocal IOL created less than half the amount of light loss than the bifocal IOL for small pupil. For large pupil, however, less light scatter was observed for the bifocal than the trifocal IOL

    Is flow velocity a significant parameter in flood damage modelling?

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    Flow velocity is generally presumed to influence flood damage. However, this influence is hardly quantified and virtually no damage models take it into account. Therefore, the influences of flow velocity, water depth and combinations of these two impact parameters on various types of flood damage were investigated in five communities affected by the Elbe catchment flood in Germany in 2002. 2-D hydraulic models with high to medium spatial resolutions were used to calculate the impact parameters at the sites in which damage occurred. A significant influence of flow velocity on structural damage, particularly on roads, could be shown in contrast to a minor influence on monetary losses and business interruption. Forecasts of structural damage to road infrastructure should be based on flow velocity alone. The energy head is suggested as a suitable flood impact parameter for reliable forecasting of structural damage to residential buildings above a critical impact level of 2 m of energy head or water depth. However, general consideration of flow velocity in flood damage modelling, particularly for estimating monetary loss, cannot be recommended

    Hole distribution for (Sr,Ca,Y,La)_14 Cu_24 O_41 ladder compounds studied by x-ray absorption spectroscopy

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    The unoccupied electronic structure for the Sr_14Cu_24O_41 family of two-leg ladder compounds was investigated for different partial substitutions of Sr^2+ by Ca^2+, leaving the nominal hole count constant, and by Y^3+ or La^3+, reducing the nominal hole count from its full value of 6 per formula unit. Using polarization-dependent x-ray absorption spectroscopy on single crystals, hole states on both the chain and ladder sites could be studied. While for intermediate hole counts all holes reside on O sites of the chains, a partial hole occupation on the ladder sites in orbitals oriented along the legs is observed for the fully doped compound Sr_14Cu_24O_41. On substitution of Ca for Sr orbitals within the ladder planes but perpendicular to the legs receive some hole occupation as well.Comment: 10 pages RevTeX style with 7 embedded figures + 1 table; accepted by Phys. Rev.
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