180,103 research outputs found

    Controlling plant architecture by manipulation of gibberellic acid signalling in petunia.

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    Since stem elongation is a gibberellic acid (GA) response, GA inhibitors are commonly used to control plant height in the production of potted ornamentals and bedding plants. In this study, we investigated interfering with GA signaling by using molecular techniques as an alternative approach. We isolated three putative GID1 genes (PhGID1A, PhGID1B and PhGID1C) encoding GA receptors from petunia. Virus-induced gene silencing (VIGS) of these genes results in stunted growth, dark-green leaves and late-flowering. We also isolated the gai mutant gene (gai-1) from Arabidopsis. We have generated transgenic petunia plants in which the gai mutant protein is over-expressed under the control of a dexamethasone-inducible promoter. This system permits induction of the dominant Arabidopsis gai mutant gene at a desired stage of plant development in petunia plants by the application of dexamethasone (Dex). The induction of gai in Dex-treated T1 petunia seedlings caused dramatic growth retardation with short internodes

    On the decomposition of Generalized Additive Independence models

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    The GAI (Generalized Additive Independence) model proposed by Fishburn is a generalization of the additive utility model, which need not satisfy mutual preferential independence. Its great generality makes however its application and study difficult. We consider a significant subclass of GAI models, namely the discrete 2-additive GAI models, and provide for this class a decomposition into nonnegative monotone terms. This decomposition allows a reduction from exponential to quadratic complexity in any optimization problem involving discrete 2-additive models, making them usable in practice

    Validation of the geriatric anxiety inventory in a duloxetine clinical trial for elderly adults with generalized anxiety disorder

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    Background: The Generalized Anxiety Inventory (GAI) has been developed for use in the assessment of anxiety symptoms in older adults (≥ 65 years), but previous validation work has not examined the psychometric qualities of the instrument in relation to treatment. The objective of this study was to examine the performance of the GAI for its internal reliability, convergent and divergent validity, and its sensitivity to treatment. Methods: Elderly patients with generalized anxiety disorder (GAD) participated in a 10-week double-blind study of duloxetine treatment for patients with GAD. Anxiety symptoms were assessed with the Hamilton Anxiety Rating Scale (HAMA), the Hospital Anxiety and Depression Scale (HADS) anxiety and depression subscales, and the GAI. Internal reliability of the GAI was assessed with Cronbach's α. Correlations among the HAMA, HADS, and GAI scores were analyzed to determine convergent and divergent validity. Patients were also compared on remission status using recommended cut-off scores for the GAI. Results: Patients with GAD, who were at least 65 years of age, were randomly assigned to double-blind treatment with either duloxetine (N = 151) or placebo (N = 140) for 10 weeks acute therapy. The mean change on the GAI was significantly greater with duloxetine compared with placebo treatment (−8.36 vs. −4.96, respectively, p ≤ 0.001). The GAI demonstrated good internal consistency, good convergent and divergent validity, but suggested cut-off values for caseness with the GAI did not correspond to remission status as measured by the HAMA. Conclusions: Within an elderly patient population with GAD, the GAI demonstrated sound psychometric qualities and sensitivity to change with treatment

    Nuclear Structure and the Fate of Core Collapse (Type II) Supernova

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    For a long time Gerry Brown and his collaborator Hans Bethe considered the question of the final fate of a core collapse (Type II) supernova. Recalling ideas from nuclear structure on Kaon condensate and a soft equation of state of the dense nuclear matter they concluded that progenitor stars with mass as low a 17-18M_\odot (including supernova 1987A) could collapse to a small mass black hole with a mass just beyond 1.5M_\odot, the upper bound they derive for a neutron star. We discuss another nuclear structure effect that determines the carbon to oxygen ratio (C/O) at the end of helium burning. This ratio also determines the fate of a Type II supernova with a carbon rich progenitor star producing a neutron star and oxygen rich collapsing to a black hole. While the C/O ratio is one of the most important nuclear input to stellar evolution it is still not known with sufficient accuracy. We discuss future efforts to measure with gamma-beam and TPC detector the 12C(a,g)16O reaction that determines the C/O ratio in stellar helium burning.Comment: This work is dedicated to the memory of my beloved teacher and friend Gerry Brown who taught me how to think and approach a problem. I consider myself very lucky to have been under the wings of this man who flew with the eagles [1]. 45 Years Of nuclear theory at Stony Brook: A Tribute To Gerald E. Brown, Nov. 24-26, 2013, Stony Brook University. Nucl. Phys. A, 201

    Comment on Esbensen, Bertsch and Snover Concerning Reconciling Coulomb Dissociation and Radiative Capture Measurements

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    The RIKEN data on the Coulomb Dissociation (CD) of 8B were shown to be in good agreement with the Direct Capture (DC) data on the 7Be(p,g)8B reaction (that were known at that time) of Filippone {\em et al.} Yet recently it was claimed that the RIKEN2 CD data must be corrected in order to be reconciled with the slope of DC data. Considering the (correct) so called scale independent b-slope parameter of the RIKEN2 CD data, the resultant corrected b-slope parameter suggested by Esbensen, Bertsch and Snover is shown to be considerably smaller than the so called average b-slope parameter of DC data. The suggested corrections of the b-slope parameter lead to a large disagreement with DC data, in sharp contrast to the claim. The slope corrections are only significant for the RIKEN2 CD data. For the GSI kinematics, where in fact one may observe slope different than for DC (at least for the GSI1 data), they find a fortuitous cancellation that leads to a vanishingly small slope correction. Hence the validity of these correction based on the observed slopes can not be substantiated.Comment: Work Supported by USDOE Grant No. DE-FG02-94ER40870. Updated as published in the Phys. Rev. Lett. on April 21, 200
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