312 research outputs found

    Plant Protection in organic production of Brassica vegetables and oilseed rape

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    Growers of organic Brassica vegetables and oilseed rape face the same potentially severe plant protection problems as their colleagues in conventional or integrated pest management systems.Management strategies in organic systems rely on preventive measures (crop rotation, crop isolation,soil management, host plant resistance, farm/field location; manipulate timing of planting or harvest; intercropping, mulching), use of functional agro-biodiversity (reduction of pest by enhancing natural enemies), release of biocontrol agents and a few approved pesticides of biological and mineral origin, as well as mating disruption or the use of anti-insect nets (Zehnder et al., 2007). The methods used in organic might also be applicable in IPM systems. However, several factors hamper wide implementation of these methods in IPM. Among the main reasons are (1) a lower efficacy compared to standard pesticide treatments, (2) higher costs, (3) lack of knowledge / information / advice on alternative methods, (4) inconvenience, and (5) the need for close collaboration between neighbouring famers to achieve good control. In the following paper, we describe the methods used in organic Brassica vegetable and oilseed rape production, and discuss their limitations

    Effects of landscape and region on pests and pathogens in Brassica vegetables and oilseed rape.

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    Abstract: Pests and pathogens of Brassica vegetables and oilseed rape are mainly managed at a field level. Management of pest insects at a farm level is only suitable for farmers owning compact areas of land, which is not the case in many central European areas. This paper discusses the effects of landscape and region on pests and pathogens in Brassica crops. Topics covered include pest and disease dispersal and persistence, regional races or biotypes, new pests and pathogens, insecticide resistance, conservation biocontrol and monitoring and forecasting

    Ecological selectivity of pesticides and application methods

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    According to David Pimentel, 20 years ago, less than 0.1% of the pesticides applied reached their target pests (Pimentel, 1995). This was partly due to ‘poor’ application methods and partly because of the minuscule amount of pesticide either picked up or consumed by the pest. At the time, Pimentel was describing the application of pesticides mainly by sprays, including aerial spraying, and both pesticide chemistry and application technology have improved since then. However, a considerable proportion of pesticides are still applied as sprays, either to crop foliage or to the soil, and this continues to be a relatively untargeted method of application

    Transitioning a maintenance culture in a plant

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1994, and Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1994.Includes bibliographical references (p. 122).by Daniel J. Hommes.M.S

    Optimization of human mesenchymal stem cell manufacturing: the effects of animal/xeno-free media.

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    Due to their immunosuppressive properties, mesenchymal stem cells (MSC) have been evaluated for the treatment of immunological diseases. However, the animal-derived growth supplements utilized for MSC manufacturing may lead to clinical complications. Characterization of alternative media formulations is imperative for MSC therapeutic application. Human BMMSC and AdMSC were expanded in media supplemented with either human platelet lysates (HPL), serum-free media/xeno-free FDA-approved culture medium (SFM/XF), or fetal bovine serum (FBS) and the effects on their properties were investigated. The immunophenotype of resting and IFN-Îł primed BMMSC and AdMSC remained unaltered in all media. Both HPL and SFM/XF increased the proliferation of BMMSC and AdMSC. Expansion of BMMSC and AdMSC in HPL increased their differentiation, compared to SFM/XF and FBS. Resting BMMSC and AdMSC, expanded in FBS or SFM/XF, demonstrated potent immunosuppressive properties in both non-primed and IFN-Îł primed conditions, whereas HPL-expanded MSC exhibited diminished immunosuppressive properties. Finally, IFN-Îł primed BMMSC and AdMSC expanded in SFM/XF and HPL expressed attenuated levels of IDO-1 compared to FBS. Herein, we provide strong evidence supporting the use of the FDA-approved SFM/XF medium, in contrast to the HPL medium, for the expansion of MSC towards therapeutic applications

    Assessment of Circulating MicroRNAs for the Diagnosis and Disease Activity Evaluation in Patients with Ulcerative Colitis by Using the Nanostring Technology

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    Background: Clinical decision and patient care management in inflammatory bowel diseases is largely based on the assessment of clinical symptoms, while the biomarkers currently in use poorly reflect the actual disease activity. Therefore, the identification of novel biomarkers will serve an unmet clinical need for IBD screening and patient management. We examined the utility of circulating microRNAs for diagnosis and disease activity monitoring in ulcerative colitis (UC) patients. Methods: Blood serum microRNAs were isolated from UC patients with active and inactive disease and healthy donors. High-throughput microRNA profiling was performed using the Nanostring technology platform. Clinical disease activity was captured by calculating the partial Mayo score. C-reactive protein (CRP) was measured in UC patients as part of their clinical monitoring. The profiles of circulating microRNAs and CRP were correlated with clinical disease indices. Results: We have identified a signature of 12 circulating microRNAs that differentiate UC patients from control subjects. Moreover, six of these microRNAs significantly correlated with UC disease activity. Importantly, a set of four microRNAs (hsa-miR-4454, hsa-miR-223-3p, hsa-miR-23a-3p, and hsa-miR-320e) which correlated with UC disease activity, were found to have higher sensitivity and specificity values than CRP. Conclusions: Circulating microRNAs provide a novel diagnostic and prognostic marker for UC patients. The use of an FDA approved platform could accelerate the application of microRNA screening in a GI clinical setting. When used in combination with current diagnostic and disease activity assessment modalities, microRNAs could improve both IBD screening and care management

    Strategies used as spectroscopy of financial markets reveal new stylized facts

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    We propose a new set of stylized facts quantifying the structure of financial markets. The key idea is to study the combined structure of both investment strategies and prices in order to open a qualitatively new level of understanding of financial and economic markets. We study the detailed order flow on the Shenzhen Stock Exchange of China for the whole year of 2003. This enormous dataset allows us to compare (i) a closed national market (A-shares) with an international market (B-shares), (ii) individuals and institutions and (iii) real investors to random strategies with respect to timing that share otherwise all other characteristics. We find that more trading results in smaller net return due to trading frictions. We unveiled quantitative power laws with non-trivial exponents, that quantify the deterioration of performance with frequency and with holding period of the strategies used by investors. Random strategies are found to perform much better than real ones, both for winners and losers. Surprising large arbitrage opportunities exist, especially when using zero-intelligence strategies. This is a diagnostic of possible inefficiencies of these financial markets.Comment: 13 pages including 5 figures and 1 tabl
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