21,060 research outputs found

    Impact of foliar diseases in organically grown barley: Influence of fertilization, nutrient content in leaves, varietal disease resistance characteristics and yield potential

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    Significant increase in severity of powdery mildew,leaf rust and net blotch with increasing N-content in plant leaves 30 days after germination (all years where the relevant diseases were present at a substantial level). This may explain: · Most of the environmental main effects (field) on disease. · Effect of treatments, i.e., treament 4 resulted in reduced N/increased K content in leaves, which coincided with reduced levels of disease. We observed no clear effect of P, Ca, S, and Zn content in leaves on disease. Micronutrients as Cu, Mo and Mn showed significant effects on powdery mildew in one year but not the other; further interpretation may not be possible due to inter-correlation among the effect of micro-nutrients. The diseases had a significant yield reducing effect, in particular powdery mildew and net blotch, which occurred at highest severities. In addition, net blotch affected root development, resulting in significant shorter roots, whereas powdery mildew did not. The effect of disease on root length was of the same order of magnitude as the factor 'variety', but larger than effects of 'year'

    Growth, current size and the role of the 'reversal paradox' in the foetal origins of adult disease: an illustration using vector geometry

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    BACKGROUND Numerous studies have reported inverse associations between birth weight and a range of diseases in later life. These have led to the development of the 'foetal origins of adult disease hypothesis'. However, many such studies have only been able to demonstrate a statistically significant association between birth weight and disease in later life by adjusting for current size. This has been interpreted as evidence that the impact of low birth weight on subsequent disease is somehow dependent on subsequent weight gain, and has led to a broadening of the hypothesis into the 'developmental origins of health and disease'. Unfortunately, much of the epidemiological evidence used for both of these interpretations is prone to a statistical artefact known as the 'reversal paradox'. The aim of this paper is to illustrate why, using vector geometry. MATERIALS AND METHODS This paper introduces the key concepts of vector geometry as applied to multiple regression analysis. This approach is then used to illustrate the similar statistical problems encountered when adjusting for current size or growth when exploring the association between birth weight and disease in later life. RESULTS Geometrically, the three covariates – birth size, growth, and current size – span only 2-dimensional space. Regressing disease in later life (i.e. the outcome variable) on any two of these covariates equates to projecting the disease variable onto the plane spanned by the three covariate vectors. The three possible regression models – where any two covariates are considered – are therefore equivalent and yield exactly the same model fit (R2). CONCLUSION Vector geometry illustrates why it is impossible to differentiate between the effects of growth from the effects of current size in studies exploring the relationship between size at birth and subsequent disease. For similar reasons, it is impossible to differentiate between the effects of growth and the effects of birth weight. Assessing the 'independent' impact of growth on later disease by adjusting for either birth weight or current size is therefore illusory

    Identification of MarvelD3 as a tight junction-associated transmembrane protein of the occludin family

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    Background: Tight junctions are an intercellular adhesion complex of epithelial and endothelial cells, and form a paracellular barrier that restricts the diffusion of solutes on the basis of size and charge. Tight junctions are formed by multiprotein complexes containing cytosolic and transmembrane proteins. How these components work together to form functional tight junctions is still not well understood and will require a complete understanding of the molecular composition of the junction. Results: Here we identify a new transmembrane component of tight junctions: MarvelD3, a four-span transmembrane protein. Its predicted transmembrane helices form a Marvel (MAL and related proteins for vesicle traffic and membrane link) domain, a structural motif originally discovered in proteins involved in membrane apposition and fusion events, such as the tight junction proteins occludin and tricellulin. In mammals, MarvelD3 is expressed as two alternatively spliced isoforms. Both isoforms exhibit a broad tissue distribution and are expressed by different types of epithelial as well as endothelial cells. MarvelD3 co-localises with occludin at tight junctions in intestinal and corneal epithelial cells. RNA interference experiments in Caco-2 cells indicate that normal MarvelD3 expression is not required for the formation of functional tight junctions but depletion results in monolayers with increased transepithelial electrical resistance. Conclusions: Our data indicate that MarvelD3 is a third member of the tight junction-associated occludin family of transmembrane proteins. Similar to occludin, normal expression of MarvelD3 is not essential for the formation of functional tight junctions. However, MarvelD3 functions as a determinant of epithelial paracellular permeability properties

    Single sided single pass submerged arc welding of austenitic stainless steel

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    The weld metal produced from a series of high productivity welds of 316LN austenitic stainless steel plate was examined to evaluate the effects of the use of a higher heat input process (> 2.5kJ/mm).This high heat input process was aimed at maximising single sided weld metal penetration in a single pass using simple square edge preparations and minimising time consuming handling operations. The evaluation was undertaken by correlating the local microstructure with the local toughness and microhardness of the cap, middle and root of the weld. It was established that the intermetallic phases / carbides present did not appear to have a significantly adverse effect on either corrosion or toughness. The phases observed and confirmed by the use of SAED were predominantly chi (χ) with some sigma( σ). No identifications were made of M23C6 which was observed in other studies of 316LN welds. A series of impact tests with variations in the notch positions showed that the thickness of the delta ferrite had an effect on the weld metal toughness. As a result of this work it was established that similar volume fractions of delta ferrite did not necessarily produce similar levels of weld metal toughness, but ferrite thickness did appear to have a contributory effect. Welding of 316LN stainless steel with a single sided single pass submerged arc welding process was satisfactorily undertaken up to 20mm plate thickness without preheat or post weld heat treatment. The ability to achieve this resulted in significant economic savings within the process for ship panel production combined with satisfactory weld metal properties

    Preparation, Characterization and NO-CO Redox Reaction Studies over Palladium and Rhodium Oxides Supported on Manganese Dioxide

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    The catalytic activity of PdO/MnO2 and Rh2O3/MnO2 is investigated for NO-CO redox reaction. Supported catalysts are prepared by wet impregnation method. Among the tested catalysts, PdO/MnO2 shows higher activity for this reaction. Active metal dispersion on MnO2 enhances the selectivity for N2 over N2O in this reaction. The XRD substantiate the formation of MnO2 monophasic phase. SEM images show the formation of elongated particles. TEM images indicate nano-size rod-like morphologies. An increase in the catalytic activity is observed on supported Pd and Rh oxides on MnO2. Temperature programed desorption studies with NO and CO are undertaken to investigate the catalytic surface studies. © 2015 BCREC UNDIP. All rights reserve

    Spatial resolution of a GEM readout TPC using the charge dispersion signal

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    A large volume Time Projection Chamber (TPC) is being considered for the central charged particle tracker for the detector for the proposed International Linear Collider (ILC). To meet the ILC-TPC spatial resolution challenge of ~100 microns with a manageable number of readout pads and channels of electronics, Micro Pattern Gas Detectors (MPGD) are being developed which could use pads comparable in width to the proportional-wire/cathode-pad TPC. We have built a prototype GEM readout TPC with 2 mm x 6 mm pads using the new concept of charge dispersion in MPGDs with a resistive anode. The dependence of transverse resolution on the drift distance has been measured for small angle tracks in cosmic ray tests without a magnetic field for Ar/CO2 (90:10). The GEM-TPC resolution with charge dispersion readout is significantly better than previous measurements carried out with conventional direct charge readout techniques.Comment: 5 figures, 10 page

    Predicting spring barley yield from variety-specific yield potential, disease resistance and straw length, and from environment-specific disease loads and weed pressure

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    Abstract For low-input crop production, well-characterised varieties increase the possibilities of managing diseases and weeds. This analysis aims at developing a framework for analyzing grain yield using external varietal information about disease resistance, weed competitiveness and yield potential and quantifying the impact of susceptibility grouping and straw length scores (as a measure for weed competitiveness) for predicting spring barley grain yield under variable biotic stress levels. The study comprised 52 spring barley varieties and 17 environments, i.e., combinations of location, growing system and year. Individual varieties and their interactions with environments were analysed by factorial regression of grain yield on external variety information combined with observed environmental disease loads and weed pressure. The external information was based on the official Danish VCU testing. The most parsimonious models explained about 50% of the yield variation among varieties including genotypeenvironment interactions. Disease resistance characteristics of varieties, weighted with disease loads of powdery mildew, leaf rust and net blotch, respectively, had a highly significant influence on grain yield. The extend to which increased susceptibility resulted in increased yield losses in environments with high disease loads of the respective diseases was predicted. The effect of externally determined straw length scores, weighted with weed pressure, was weaker although significant for weeds with creeping growth habit. Higher grain yield was thus predicted for taller plants under weed pressure. The results are discussed in relation to the model ramework, impact of the considered traits and use of information from conventional variety testing in organic cropping systems

    Can a wormhole supported by only small amounts of exotic matter really be traversable?

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    Recent studies have shown that (a) quantum effects may be sufficient to support a wormhole throat and (b) the total amount of "exotic matter" can be made arbitrarily small. Unfortunately, using only small amounts of exotic matter may result in a wormhole that flares out too slowly to be traversable in a reasonable length of time. Combined with the Ford-Roman constraints, the wormhole may also come close to having an event horizon at the throat. This paper examines a model that overcomes these difficulties, while satisfying the usual traversability conditions. This model also confirms that the total amount of exotic matter can indeed be made arbitrarily small.Comment: 8 pages, AMSTe

    Application of a New Non-Linear Least Squares Velocity Curve Analysis Technique for Spectroscopic Binary Stars

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    Using measured radial velocity data of nine double lined spectroscopic binary systems NSV 223, AB And, V2082 Cyg, HS Her, V918 Her, BV Dra, BW Dra, V2357 Oph, and YZ Cas, we find corresponding orbital and spectroscopic elements via the method introduced by Karami & Mohebi (2007a) and Karami & Teimoorinia (2007). Our numerical results are in good agreement with those obtained by others using more traditional methods.Comment: 6 pages, 3 figures. Accepted for publication in Astrophysics & Space Scienc

    The Y-box factor ZONAB/DbpA associates with GEF-H1/Lfc and mediates Rho-stimulated transcription

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    Epithelial tight junctions recruit different types of signalling proteins that regulate cell proliferation and differentiation. Little is known about how such proteins interact functionally and biochemically with each other. Here, we focus on the Y-box transcription factor ZONAB (zonula occludens 1-associated nucleic-acid-binding protein)/DbpA (DNA-binding protein A) and the Rho GTPase activator guanine nucleotide exchange factor (GEF)-H1/Lbc's first cousin, which are two tight-junction-associated signalling proteins that regulate proliferation. Our data show that the two proteins interact and that ZONAB activity is Rho-dependent. Overexpression of GEF-H1 induces accumulation of ZONAB in the nucleus and activates transcription. Microtubule-affinity regulating kinase/partition-defective-1, another type of GEF-H1-associated signalling protein, remains in the cytoplasm and partially co-localizes with the exchange factor. GEF-H1 and ZONAB are required for expression of endogenous cyclin D1, a crucial RhoA signalling target gene, and GEF-H1-stimulated cyclin D1 promoter activity requires ZONAB. Our data thus indicate that GEF-H1 and ZONAB form a signalling module that mediates Rho-regulated cyclin D1 promoter activation and expression
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