3,100 research outputs found
Influence of season, drought and xylem ABA on stomatal responses to leaf-to-air vapour pressure difference of trees of the Australian wet-dry tropics
This paper reports the results of two experiments undertaken to investigate the influence of season and soil drying on stomatal responses to leaf-to-air vapour pressure differences. We examined the response of stomatal conductance to increasing leaf-to-air vapour pressure difference, in the wet and dry seasons, of five tropical tree species. We also examined leaves of these species for anatomical differences to determine whether this could explain differences in stomatal sensitivity to leaf-to-air vapour pressure differences. Finally, we conducted a split-root experiment with one of those species to look for interactions between xylem abscisic acid concentration, predawn water potential, leaf area to root mass ratio and stomatal responses to leaf-to-air vapour pressure differences. Stomatal conductance declined linearly with increasing leaf-to-air vapour pressure difference in all species. Leaves that expanded in the 'dry' season were more sensitive to leaf-to-air vapour pressure differences than those that had expanded in the 'wet' season. The value of leaf-to-air vapour pressure difference where 50% of extrapolated maximum stomatal conductance would occur was 5.5 kPa for wet season but only 3.4 kPa for dry season leaves. In the wet season, transpiration rate increased with increasing leaf-to-air vapour pressure difference in most example species. However, in the dry season, transpiration was constant as leaf-to-air vapour pressure differences increased in most cases. There were significant changes in the proportion of cell wall exposed to air space in leaves, between wet and dry seasons, in three of four species examined. In the split-root experiment, a very mild water stress increased stomatal sensitivity to leaf-to-air vapour pressure differences, and stomatal conductivity declined linearly with decreasing predawn water potential. However, levels of ABA in the xylem did not change, and stomatal sensitivity to exogenous ABA did not change. The ratio of leaf area to root mass declined during water stress and was correlated to changes in stomatal sensitivity to leaf-to-air vapour pressure differences
Heavy-light decay constants from clover heavy quark action in QCD with two flavors of dynamical quarks
We present results on an analysis of the decay constants f_B and f_Bs with
two flavours of sea quark. The calculation has been carried out on 3 different
bare gauge couplings and 4 sea quark masses at each gauge coupling, with
m_pi/m_rho ranging from 0.8 to 0.6. We employ the Fermilab formalism to perform
calculations with heavy quarks whose mass is in the range of the b-quark. A
detailed comparison with a quenched calculation using the same action is made
to elucidate the effects due to the sea quarks.Comment: Contribution to Lattice 99 (Heavy Quarks). Latex file, uses
espcrc2.sty and epsf.sty. 3 pages, 3 encapsulated postscript figure
Full QCD light hadron spectrum from the CP-PACS
We report on an on-going two-flavor full QCD study on CP-PACS using an
RG-improved gauge action and a tadpole-improved SW quark action. Runs are made
for three lattice spacings , 1.3, and 2.5 GeV on
, , and lattices. Four sea quark
masses having --0.6 are simulated, for each
of which hadron masses are evaluated for valence quark masses corresponding to
--0.5. Results for hadron and light quark
masses are presented and compared with those obtained in quenched QCD.Comment: LATTICE98(spectrum), 3 pages, 3 figure
Chemo-Sensitive Running Droplet
Chemical control of the spontaneous motion of a reactive oil droplet moving
on a glass substrate under an aqueous phase is reported. Experimental results
show that the self-motion of an oil droplet is confined on an acid-treated
glass surface. The transient behavior of oil-droplet motion is also observed
with a high-speed video camera. A mathematical model that incorporates the
effect of the glass surface charge is built based on the experimental
observation of oil-droplet motion. A numerical simulation of this mathematical
model reproduced the essential features concerning confinement within a certain
chemical territory of oil-droplet motion, and also its transient behavior. Our
results may shed light on physical aspects of reactive spreading and a
chemotaxis in living things.Comment: 17 pages, 10 figure
Cost-effectiveness analysis of the New South Wales adult drug court program
In New South Wales, Australia, a cost-effectiveness evaluation was conducted of an adult drug court (ADC) program as an alternative to jail for criminal offenders addicted to illicit drugs. This article describes the program, the cost-effectiveness analysis, and the results. The results of this study reveal that, for the 23-month period of the evaluation, the ADC was as cost-effective as were conventional sanctions in delaying the time to the first offense and more cost-effective in reducing the frequency of offending for those outcome measures selected. Although the evaluation was conducted using the traditional steps of a cost-effectiveness analysis, because of the complexity of the program and data limitations it was not always possible to adhere to textbook procedures. As such, each step involved in undertaking the cost-effectiveness analysis is discussed, highlighting the key issues faced in the evaluation. © 2004 Sage Publications
Quenched Light Hadron Spectrum with the Wilson Quark Action: Final Results from CP-PACS
We report the final results of the CP-PACS calculation for the quenched light
hadron spectrum with the Wilson quark action. Our data support the presence of
quenched chiral singularities, and this motivates us to use mass formulae based
on quenched chiral perturbation theory in order to extrapolate hadron masses to
the physical point. Hadron masses and decay constants in the continuum limit
show unambiguous systematic deviations from experiment. We also report the
results for light quark masses.Comment: LATTICE98(spectrum). The poster at Lattice98 can be obtained from
http://www.rccp.tsukuba.ac.jp/people/yoshie/Lat98.Poster
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