1,173 research outputs found
A note on the use of microbial insecticides for the control of tomato hornworms on flue-cured tobacco
Deux formulations du Bacillus thuringiensis, la BactospĂ©ine-A et le Thuricide-HPC, ont Ă©tĂ© appliquĂ©es sur des plantes de tabac (Nicotiana tabacum) Ă©tĂȘtĂ©es afin d'Ă©valuer leur efficacitĂ© envers le sphinx de la tomate (Manduca quinquemaculata) en laboratoire et au champ. Les deux insecticides ont procurĂ© une rĂ©pression complĂšte des sphinx de la tomate, peu importe les doses appliquĂ©es. Toutes les larves se sont nourries lĂ©gĂšrement ou modĂ©rĂ©ment sur les feuilles traitĂ©es au cours de la premiĂšre journĂ©e suivant le traitement mais par la suite, les larves sont demeurĂ©es inactives sur les feuilles traitĂ©es jusqu'Ă leur mort. Il y a peu d'Ă©vidence d'une alimentation subsĂ©quente quand les feuilles ont Ă©tĂ© examinĂ©es. Ces insecticides microbiens n'ont eu aucun effet nĂ©faste sur le parasite du sphinx de la tomate, Cotesia congragata, et aucune phytotoxicitĂ© n'a Ă©tĂ© observĂ©e.Two formulations of Bacillus thuringiensis, Bactospeine-A and Thuricide-HPC, were applied on tobacco plants after topping to evaluate their effectiveness against tomato hornworm (Manduca quinquemaculata) in the laboratory and field. Both materials, regardless of the rates applied, gave complete control of the tomato hornworms. All the larvae fed slightly or moderately on the treated leaves during the first day after treatment, but thereafter, the larvae remained inactive on the treated leaves until death. There was little evidence of further feeding when the leaves were examined. The microbial insecticides had no detrimental effect on the beneficial insect parasite, Cotesia congragata, and no phytotoxicity was observed
Graded Symmetry Algebras of Time-Dependent Evolution Equations and Application to the Modified KP equations
By starting from known graded Lie algebras, including Virasoro algebras, new
kinds of time-dependent evolution equations are found possessing graded
symmetry algebras. The modified KP equations are taken as an illustrative
example: new modified KP equations with arbitrary time-dependent
coefficients are obtained possessing symmetries involving arbitrary
functions of time. A particular graded symmetry algebra for the modified KP
equations is derived in this connection homomorphic to the Virasoro algebras.Comment: 19 pages, latex, to appear in J. Nonlinear Math. Phy
Integration of Unmanned Aerial Systems in Class E Airspace: The Effect on Air Traffic Controller Workload
As technology rapidly advances and our imagination is no longer fantasy but instead reality, the aviation community needs to concentrate on the harsh truth of airspace safety. In the situation of integrating unmanned aerial systems (UASs) into the National airspace, UASs outside of terminal areas would generally be permitted to fly their preferred routes, and self-separate, with minimal intervention from air traffic control. From an air traffic control perspective, the integration could raise a number of human performance problems including workload extremes and passive-monitoring demands. One fundamental requirement for operation in the National Air Space is to preserve the safety of the general public. This paper describes an experimental evaluation of the effect different levels of UAS intent information has on air traffic controller workload. The simulation specifically manipulates intent sharing, that is, whether unmanned aerial vehicles provided advance notice of their intended maneuvers. The Effects on air traffic controller workload when control capability is altered were also explored
Applicability of perturbative QCD to decays
We develop perturbative QCD factorization theorem for the semileptonic heavy
baryon decay , whose form factors are
expressed as the convolutions of hard quark decay amplitudes with universal
and baryon wave functions. Large logarithmic
corrections are organized to all orders by the Sudakov resummation, which
renders perturbative expansions more reliable. It is observed that perturbative
QCD is applicable to decays for velocity transfer
greater than 1.2. Under requirement of heavy quark symmetry, we predict the
branching ratio , and determine
the and baryon wave functions.Comment: 12 pages in Latex file, 3 figures in postscript files, some results
are changed, but the conclusion is the sam
Understorey plant community and light availability in conifer plantations and natural hardwood forests in Taiwan
Questions: What are the effects of replacing mixed species natural forests with Cryptomeria japonica plantations on understorey plant functional and species diversity? What is the role of the understorey light environment in determining understorey diversity and community in the two types of forest?
Location: Subtropical northeast Taiwan.
Methods: We examined light environments using hemispherical photography, and diversity and composition of understorey plants of a 35âyr C. japonica plantation and an adjacent natural hardwood forest.
Results: Understorey plant species richness was similar in the two forests, but the communities were different; only 18 of the 91 recorded understorey plant species occurred in both forests. Relative abundance of plants among different functional groups differed between the two forests. Relative numbers of shadeâtolerant and shadeâintolerant seedling individuals were also different between the two forest types with only one shadeâintolerant seedling in the plantation compared to 23 seedlings belonging to two species in the natural forest. In the natural forest 11 species of tree seedling were found, while in the plantation only five were found, and the seedling density was only one third of that in the natural forest. Across plots in both forests, understorey plant richness and diversity were negatively correlated with direct sunlight but not indirect sunlight, possibly because direct light plays a more important role in understorey plant growth.
Conclusions: We report lower species and functional diversity and higher light availability in a natural hardwood forest than an adjacent 30âyr C. japonica plantation, possibly due to the increased dominance of shadeâintolerant species associated with higher light availability. To maintain plant diversity, management efforts must be made to prevent localized losses of shadeâadapted understorey plants
Matrix theory of gravitation
A new classical theory of gravitation within the framework of general
relativity is presented. It is based on a matrix formulation of
four-dimensional Riemann-spaces and uses no artificial fields or adjustable
parameters. The geometrical stress-energy tensor is derived from a matrix-trace
Lagrangian, which is not equivalent to the curvature scalar R. To enable a
direct comparison with the Einstein-theory a tetrad formalism is utilized,
which shows similarities to teleparallel gravitation theories, but uses complex
tetrads. Matrix theory might solve a 27-year-old, fundamental problem of those
theories (sec. 4.1). For the standard test cases (PPN scheme,
Schwarzschild-solution) no differences to the Einstein-theory are found.
However, the matrix theory exhibits novel, interesting vacuum solutions.Comment: 24 page
The effects of the bacterial interaction with visible-light responsive titania photocatalyst on the bactericidal performance
Bactericidal activity of traditional titanium dioxide (TiO2) photocatalyst is effective only upon irradiation by ultraviolet light, which restricts the potential applications of TiO2 for use in our living environments. Recently carbon-containing TiO2 was found to be photoactive at visible-light illumination that affords the potential to overcome this problem; although, the bactericidal activity of these photocatalysts is relatively lower than conventional disinfectants. Evidenced from scanning electron microscopy and confocal Raman spectral mapping analysis, we found the interaction with bacteria was significantly enhanced in these anatase/rutile mixed-phase carbon-containing TiO2. Bacteria-killing experiments indicate that a significantly higher proportion of all tested pathogens including Staphylococcus aureus, Shigella flexneri and Acinetobacter baumannii, were eliminated by the new nanoparticle with higher bacterial interaction property. These findings suggest the created materials with high bacterial interaction ability might be a useful strategy to improve the antimicrobial activity of visible-light-activated TiO2
The Influences of Diesel Particulate Filter Installation on Air Pollutant Emissions for Used Vehicles
Three kinds of diesel particulate filters (DPFs) were installed on used diesel-powered vehicles to investigate their influences on air pollutant emissions. The air pollutant emissions were measured before, after and running for specific distances to assess the deterioration effect. The emission measurement was performed on a chassis dynamometer. The results show that emissions of smoke, CO and HC are all reduced after DPF installation. After 20000 km driving, the emission concentrations of the above 3 criteria air pollutants do not increase in comparison with that right after installation. When DPFs are installed, the emissions of PAHs (polycyclic aromatic hydrocarbons) are reduced by 85.6-89.4% and 69.0-89.2% for heavy-duty diesel vehicles (HDVs) and light-duty diesel vehicles (LDVs), respectively. After driving 20000 km for HDVs and 2500 km for LDVs, PAH emissions do not increase in comparison with that right after installation, indicating that the DPFs do not deteriorate after driving for the test mileages. The lower molecular weight PAHs predominates in the exhaust both before and after DPF installation. The results also show the reduction rate is higher for higher molecular weight PAHs due to their tendency to adsorb on particulate
Dynamical spin correlations in Heisenberg ladder under magnetic field and correlation functions in SO(5) ladder
The zero-temperature dynamical spin-spin correlation functions are calculated
for the spin-1/2 two-leg Heisenberg ladder in a magnetic field above the lower
critical field Hc1. The dynamical structure factors are calculated which
exhibit both massless and massive excitations. These modes appear in different
sectors characterized by the parity in the rung direction and by the momentum
in the direction of the chains. The structure factors have power-law
singularities at the lower edges of their support. The results are also
applicable to spin-1 Heisenberg chain. The implications are briefly discussed
for various correlation functions and the pi-resonance in the SO(5) symmetric
ladder model.Comment: 15 pages, 6 figures, added references; final version to appear in
Phys. Rev.
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