13,996 research outputs found
Overexpression of beta-carotene hydroxylase enhances stress tolerance in Arabidopsis
Plant stress caused by extreme environmental conditions is already a principal reason for yield reduction in crops. The threat of global environment change makes it increasingly important to generate crop plants that will withstand such conditions. Stress, particularly stress caused by increased sunlight, leads to the production of reactive oxygen species that cause photo-oxidative cell damage. Carotenoids, which are present in the membranes of all photosynthetic organisms, help protect against such light-dependent oxidative damage. In plants, the xanthophyll cycle (the reversible interconversion of two carotenoids, violaxanthin and zeaxanthin) has a key photoprotective role and is therefore a promising target for genetic engineering to enhance stress tolerance. Here we show that in Arabidopsis thaliana overexpression of the chyB gene that encodes -carotene hydroxylase—an enzyme in the zeaxanthin biosynthetic pathway—causes a specific twofold increase in the size of the xanthophyll cycle pool. The plants are more tolerant to conditions of high light and high temperature, as shown by reduced leaf necrosis, reduced production of the stress indicator anthocyanin and reduced lipid peroxidation. Stress protection is probably due to the function of zeaxanthin in preventing oxidative damage of membranes
As-built specification for CLASSY conversion
There are no author-identified significant results in this report
The why's the limit: curtailing self-enhancement with explanatory introspection
Self-enhancement is linked to psychological gains (e.g., subjective well-being, persistence in adversity) but also to intrapersonal and interpersonal costs (e.g., excessive risk taking, antisocial behavior). Thus, constraints on self-enhancement may sometimes afford intrapersonal and interpersonal advantages. We tested whether explanatory introspection (i.e., generating reasons for why one might or might not possess personality traits) constitutes one such constraint. Experiment 1 demonstrated that explanatory introspection curtails self-enhancement. Experiment 2 clarified that the underlying mechanism must (a) involve explanatory questioning rather than descriptive imagining, (b) invoke the self rather than another person, and (c) feature written expression rather than unaided contemplation. Finally, Experiment 3 obtained evidence that an increase in uncertainty about oneself mediates the effect
JSU Writing Project Anthology | Summer 2005
Theme: Stepping into the Spotlight as Teachers, as Writers, as Leadershttps://digitalcommons.jsu.edu/eng_writ_proj_anth/1017/thumbnail.jp
JSU Writing Project Anthology | Summer 1997
https://digitalcommons.jsu.edu/eng_writ_proj_anth/1009/thumbnail.jp
Laminar separation bubbles in two and three dimensional incompressible flow.
PhDA theoretical and experimental study is made of the
closed 'bubbles` of separated flow formed when a laminar
boundary layer separates from an aerofoil surface and,
after undergoing transition to turbulence, subsequently
re-attaches. Attention is mainly confined to the
so-called 'short' type of bubble, which is distinguished
from the 'long' type by its relatively slight overall
effect upon the pressure distribution.
In Part I, a semi-empirical theory for the
prediction of the growth and bursting of two-dimensional
short bubbles is developed. The existing data concerning
short bubbles are re-examined, with particular
emphasis upon the conditions governing re-attachment.
A criterion for the determination of turbulent re-attachment
is proposed, and approximate quadrature methods
developed for the calculation of the momentum thickness
in the separated region. These results, together with
am empirical formula for the determination of the
position of transition, are combined with a simplified
model of the pressure distritbution in the bubble region
to predict the re-attachment position. It is found that,
for a given imposed pressure distribution, there exists
a Reynolds number at separation below which re-attachment
is impossible. This is associated with the phenomenon
of short bubble bursting. The predictions of the theory
are in reasonable quantitative agreement with experiment.
Part II deals with bubbles in three-dimensional
flow. Experiments are described in which separation
bubbles were produced using an apparatus closely
simulating conditions near the leading-edge of a swept
wing of infinite span. Measurements of surface pressure,
mean velocity and turbulence level are presented, from
which it is deduced that the bubble structure is similar
to that of two-dimensional bubbles, apart from the
existence of cross-flows in the shear-layer and a strong
spanwise flow in the reverse-flow vortex. An extension
of the two-dimensional bursting theory by means of the
independence principle is in reasonable agreement with measured bursting parameters.Ministry of Technolog
Alien Registration- Hayes, Horton P. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/24531/thumbnail.jp
Alien Registration- Hayes, Horton P. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/24531/thumbnail.jp
JSU Writing Project Anthology | Summer 2012
Theme: Writing Out of the Boxhttps://digitalcommons.jsu.edu/eng_writ_proj_anth/1024/thumbnail.jp
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