801 research outputs found

    Downy Mildew

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    NYS IPM Type: Fruits IPM Fact SheetDowny mildew, a fungal disease native to North America, attacks most species of wild and cultivated grape. The disease was inadvertently introduced into European vineyards in the late 1870’s where it devastated the European grape, Vitis vinifera, which is generally more susceptible to the disease than native American grapes. Today, the disease can be found on grapevines in most regions of the world that are wet during the growing season. The fungus causes direct yield losses by rotting inflorescences, clusters, and shoots, and indirect losses by prematurely defoliating vines which increases their susceptibility to winter injury and delays ripening of the fruit

    The effect of operating conditions on post-injection fuel discharge in an optical engine

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    After the end of injection, the needle closes and residual fuel present inside the injector sac and orifices is discharged due to the high fluid inertia. This so-called post-injection fuel discharge can present several problems. The excess fuel can undergo incomplete combustion due to its large, slow moving and often surface-bound nature. Not only does this have a negative effect on emissions and performance, but it has been speculated that the by-products of incomplete combustion are implicated in the growth of carbonaceous deposits on the tips of fuel injectors. Accumulation of these deposits is known to lead to premature fuel injector failure that can lead to re-ductions in power output and engine lifetime. Seeing as modern multiple-injection strategies give rise to an in-creased number of transient injection phases, post-injection discharges are an increasingly common occurrence during normal operating conditions. In order to develop a phenomenological model for the fluid dynamics after the end of injection, there is a need to characterise the causes of this discharge and how they might be influenced by engine operating conditions. In this study we present ongoing analysis into results from the first visualisation of post injection fuel discharge at the microscopic level under engine-like operating conditions. We observed the process of fuel discharge for multi-hole injectors, using a high-speed camera fitted with a long-distance micro-scope and a high-speed laser illumination source. We related the effect of a variety of operating conditions on the severity of this process, including injection pressure and in-cylinder pressure along with a characterisation of the dynamics of the various modes by which these undesired liquid structures are produced. We present the different modes by which this process occurs and we conclude that the extent of post-injection discharge depends on both the in-cylinder and injection pressures

    Confirming Bank Liability in Letter of Credit Transactions: Whose Bank Is It Anyway?

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    Context. The abundance of deuterated molecules in a star-forming region is sensitive to the environment in which they are formed. Deuteration fractions, in other words the ratio of a species containing D to its hydrogenated counterpart, therefore provide a powerful tool for studying the physical and chemical evolution of a star-forming system. While local low-mass star-forming regions show very high deuteration ratios, much lower fractions are observed towards Orion and the Galactic centre. Astration of deuterium has been suggested as a possible cause for low deuteration in the Galactic centre. Aims. We derive methanol deuteration fractions at a number of locations towards the high-mass star-forming region NGC 6334I, located at a mean distance of 1.3 kpc, and discuss how these can shed light on the conditions prevailing during its formation. Methods. We use high sensitivity, high spatial and spectral resolution observations obtained with the Atacama Large Millimeter/ submillimeter Array to study transitions of the less abundant, optically thin, methanol-isotopologues: 13CH3OH, CH318OH, CH2DOH and CH3OD, detected towards NGC 6334I. Assuming local thermodynamic equilibrium (LTE) and excitation temperatures of ~120–330 K, we derive column densities for each of the species and use these to infer CH2DOH/CH3OH and CH3OD/CH3OH fractions. Results. We derive column densities in a range of (0.8–8.3) × 1017 cm−2 for 13CH3OH, (0.13–3.4) × 1017 cm−2 for CH318OH, (0.03–1.63) × 1017 cm−2 for CH2DOH and (0.15–5.5) × 1017 cm−2 for CH3OD in a ~1″ beam. Interestingly, the column densities of CH3OD are consistently higher than those of CH2DOH throughout the region by factors of 2–15. We calculate the CH2DOH to CH3OH and CH3OD to CH3OH ratios for each of the sampled locations in NGC 6334I. These values range from 0.03% to 0.34% for CH2DOH and from 0.27% to 1.07% for CH3OD if we use the 13C isotope of methanol as a standard; using the 18 O-methanol as a standard, decreases the ratios by factors of between two and three. Conclusions. All regions studied in this work show CH2DOH/CH3OH as well as CH2DOH/CH3OD values that are considerably lower than those derived towards low-mass star-forming regions and slightly lower than those derived for the high-mass star-forming regions in Orion and the Galactic centre. The low ratios indicate a grain surface temperature during formation ~30 K, for which the efficiency of the formation of deuterated species is significantly reduced. Therefore, astration of deuterium in the Galactic centre cannot be the explanation for its low deuteration ratio but rather the high temperatures characterising the region

    Activation of CD22; a Potential Novel Marker for Ovarian Cancer

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    CD22 in the human genome codes for a protein of the same name, which is normally expressed only on the surface of B-lymphocytes. The primary hypothesis is that inappropriate activation of CD22 enables cell metastasis to lymph nodes and bone. The aim of this research is to determine whether CD22 is activated in cancerous ovarian cell lines, whether CD22 is expressed on the surface of these cells, and to compare the expression of CD22 expression on B-cell lines with cancerous ovarian cells to determine expression patterns and characterize normal and aberrant CD22 receptor substrate interactions on bone marrow stromal cells. This research will improve understanding of aberrant expression of CD22 on tumors, which may potentially be used for antibody-directed therapy for ovarian cancer

    Non-perturbative contributions to the plane-wave string mass matrix

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    D-instanton contributions to the mass matrix of arbitrary excited string states of type IIB string theory in the maximally supersymmetric plane-wave background are calculated to leading order in the string coupling using a supersymmetric light-cone boundary state formalism. The explicit non-perturbative dependence of the mass matrix on the complex string coupling, the plane-wave mass parameter and the mode numbers of the excited states is determined.Comment: 25 pages, 1 figure. v3: corrected minor typos, added referenc

    A Simple Model of Liquid-liquid Phase Transitions

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    In recent years, a second fluid-fluid phase transition has been reported in several materials at pressures far above the usual liquid-gas phase transition. In this paper, we introduce a new model of this behavior based on the Lennard-Jones interaction with a modification to mimic the different kinds of short-range orientational order in complex materials. We have done Monte Carlo studies of this model that clearly demonstrate the existence of a second first-order fluid-fluid phase transition between high- and low-density liquid phases

    TITAN's Digital RFQ Ion Beam Cooler and Buncher, Operation and Performance

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    We present a description of the Radio Frequency Quadrupole (RFQ) ion trap built as part of the TITAN facility. It consists of a gas-filled, segmented, linear Paul trap and is the first stage of the TITAN setup with the purpose of cooling and bunching radioactive ion beams delivered from ISAC-TRIUMF. This is the first such device to be driven digitally, i.e., using a high voltage (Vpp=400 VV_{pp} = \rm{400 \, V}), wide bandwidth (0.2<f<1.2 MHz0.2 < f < 1.2 \, \rm{MHz}) square-wave as compared to the typical sinusoidal wave form. Results from the commissioning of the device as well as systematic studies with stable and radioactive ions are presented including efficiency measurements with stable 133^{133}Cs and radioactive 124,126^{124, 126}Cs. A novel and unique mode of operation of this device is also demonstrated where the cooled ion bunches are extracted in reverse mode, i.e., in the same direction as previously injected.Comment: 34 pages, 17 figure

    Stringing Spins and Spinning Strings

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    We apply recently developed integrable spin chain and dilatation operator techniques in order to compute the planar one-loop anomalous dimensions for certain operators containing a large number of scalar fields in N =4 Super Yang-Mills. The first set of operators, belonging to the SO(6) representations [J,L-2J,J], interpolate smoothly between the BMN case of two impurities (J=2) and the extreme case where the number of impurities equals half the total number of fields (J=L/2). The result for this particular [J,0,J] operator is smaller than the anomalous dimension derived by Frolov and Tseytlin [hep-th/0304255] for a semiclassical string configuration which is the dual of a gauge invariant operator in the same representation. We then identify a second set of operators which also belong to [J,L-2J,J] representations, but which do not have a BMN limit. In this case the anomalous dimension of the [J,0,J] operator does match the Frolov-Tseytlin prediction. We also show that the fluctuation spectra for this [J,0,J] operator is consistent with the string prediction.Comment: 27 pages, 4 figures, LaTex; v2 reference added, typos fixe
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