759 research outputs found

    Application of a mustard root bioassy to assess phytotoxicity of Group 2 herbicides

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    Non-Peer ReviewedGroup 2 herbicides exhibit high bioactivity at low concentrations in soil and may persist into the next growing season causing crop injury. A bioassay that is suitable for the detection of a range of Group 2 herbicides was developed; in this bioassay, a root growth inhibition of oriental mustard is used for the determination of the herbicide concentration in soil. The Group 2 herbicides included were: Everest (flucarbazone-sodium), Frontline (florasulam), Sundance (sulfosulfuron), and Odyssey (imazamox + imazethapyr). This bioassay was used to examine the degree of root inhibition by simultaneous application of two Group 2 herbicides. Application of varying levels of flucarbazone or sulfosulfuron combined with Odyssey resulted in root length inhibition that was comparable to the root length inhibition caused by application of flucarbazone alone or sulfosulfuron alone and Odyssey alone, possibly indicating an additive effect of these pairs of herbicides. Further studies are needed to examine which combinations of Group 2 herbicides under what environmental and soil conditions may result in “stacking” causing increased plant injury

    Quartic Anomalous Couplings in γγ\gamma\gamma Colliders

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    We study the constraints on the vertices W+W−ZγW^+W^- Z\gamma, W+W−γγW^+W^-\gamma\gamma, and ZZγγZZ\gamma\gamma that can be obtained from triple-gauge-boson production at the next generation of linear e+e−e^+e^- colliders operating in the γγ\gamma\gamma mode. We analyze the processes γγ→W+W−V\gamma\gamma \to W^+W^-V (V=ZV=Z, or γ\gamma) and show that these reactions increase the potential of e+e−e^+e^- machines to search for anomalous four-gauge-boson interactions.Comment: 15 pages, Latex file using ReVteX, 4 uufiled figures include

    Environment-wide association study to comprehensively test and validate associations between nutrition and lifestyle factors and testosterone deficiency: NHANES 1988-1994 and 1999-2004

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    PURPOSE Testosterone (T) plays an important role in men's health and its deficiency is linked with poorer health. However, the role of nutritional and lifestyle factors in T regulation and production remains unclear. The objectives are to comprehensively test the cross-sectional associations of nutritional and lifestyle factors with T deficiency and to validate the associations in the NHANES survey. METHODS We performed weighted multivariable logistic regression analysis to examine the association of 173 nutritional and lifestyle factors with T deficiency (total testosterone ≀ 3.5 ng/mL) in NHANES III as the discovery set (mean age 41). We controlled for multiple comparisons with a false discovery rate (FDR) < 5% and replicated in NHANES 1999-2004 (mean age 44). RESULTS We identified seven nutritional factors as being inversely associated with T deficiency in NHANES 1999-2004, namely dietary intake of vitamin A, protein, saturated fatty acids, monounsaturated fatty acids, total fats, saturated fatty acid 16:0, and phosphorus. In a multivariable model, only vitamin A intake remained significantly associated with T deficiency (OR 0.97, 95% CI 0.94-0.99). Principal component analysis suggested that the two principal components, (1) dietary fats, protein, and phosphorous and (2) total vitamin A, may be associated with T deficiency. CONCLUSION Our systematic evaluation provided new insight into the modifiable factors that could play a role in the regulation of T production. This study has the potential to contribute to the current body of literature which seeks to formulate a clinical definition of T deficiency after taking into account nutritional and lifestyle factors

    Physics at the Linear Collider

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    The physics at the planned e+e−e^+e^- colliders is discussed around three main topics corresponding to different manifestations of symmetry breaking: WW physics in the no Higgs scenario, studies of the properties of the Higgs and precision tests of SUSY. A comparison with the LHC is made for all these cases. The γγ\gamma \gamma mode of the linear collider will also be reviewed.Comment: 31 pages, 12 figures. Invited talk given at the Fifth Workshop on High Energy Physics Phenomenology, Inter-University Centre for Astronomy and Astrophysics, Pune, India, January 12 - 26, 199

    The visible effect of a very heavy magnetic monopole at colliders

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    If a heavy Dirac monopole exists, the light-to-light scattering below the monopole production threshold is enhanced due to strong coupling of monopoles to photons. At the next Linear Collider with electron beam energy 250 GeV this photon pair production could be observable at monopole masses less than 2.5-6.4 TeV in the e+e−e^+e^- mode or 3.7-10 TeV in the γγ\gamma\gamma mode, depending on the monopole spin. At the upgraded Tevatron such an effect is expected to be visible at monopole masses below 1-2.5 TeV. The strong dependence on the initial photon polarizations allows to find the monopole spin in experiments at e+e−e^+e^- and γγ\gamma\gamma colliders. We consider the ZγZ\gamma production and the 3γ3\gamma production at e+e−e^+e^- and pppp or ppˉp\bar{p} colliders via the same monopole loop. The possibility to discover these processes is significantly lower than that of the γγ\gamma\gamma case.Comment: 18 pages, 2 figures, RevTe

    Radiative production of invisible charginos in photon photon collision

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    If in a supersymmetric model, the lightest chargino is nearly degenerate with the lightest neutralino, the former can decay into the latter alongwith a soft pion (or a lepton-neutrino pair). Near degeneracy of the chargino and neutralino masses can cause the other decay products (the pion or the lepton) to be almost invisible. Photon-photon colliders offer a possibility of clean detection of such an event through a hard photon tag.Comment: 12 pages, 5 postscript figure

    The Higgs - photon - Z boson coupling revisited

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    We analyze the coupling of CP-even and CP-odd Higgs bosons to a photon and a Z boson in extensions of the Standard Model. In particular, we study in detail the effect of charged Higgs bosons in two-Higgs doublet models, and the contribution of SUSY particle loops in the minimal supersymmetric extension of the Standard Model. The Higgs-γZ\gamma Z coupling can be measured in the decay Z→γZ \to \gamma+Higgs at e+e−e^+e^- colliders running on the Z resonance, or in the reverse process Higgs →Zγ\to Z \gamma with the Higgs boson produced at LHC. We show that a measurement of this coupling with a precision at the percent level, which could be the case at future e+e−e^+e^- colliders, would allow to distinguish between the lightest SUSY and standard Higgs bosons in large areas of the parameter space.Comment: 18 pages LaTex + 7 figures (ps). Typo corrected in eq.(5

    Detecting and Studying Higgs Bosons at a Photon-Photon Collider

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    We examine the potential for detecting and studying Higgs bosons at a photon-photon collider facility associated with a future linear collider. Our study incorporates realistic \gam\gam luminosity spectra based on the most probable available laser technology. Results include detector simulations. We study the cases of: a) a SM-like Higgs boson; b) the heavy MSSM Higgs bosons; c) a Higgs boson with no WW/ZZWW/ZZ couplings from a general two Higgs doublet model.Comment: 52 pages, 26 figures, revised version with new appendi
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