1,300 research outputs found
Bioactivity of Cicuta virosa L. var. latisecta Celak. (Umbelliferae: Cicutal) against Red Imported Fire Ant under Laboratory and Field Conditions
We evaluated the bioactivities of compounds from Cicuta virosa L. var. latisecta Celak. against red imported fire ants (Solenopsis invicta Buren) under field and laboratory conditions. The compounds were as follows: methanol extract; petroleum ether, chloroform, and ethyl acetate fractions from the methanol extract; and the active compound isoimperatorin, which was isolated from the chloroform-fraction. The 7 d LC50 values of the methanol extract, petroleum ether, chloroform, and ethyl acetate fractions and isoimperatorin toward micrergates were 111.20, 214.45, 40.90, 569.67, and 25.73 mg/kg, respectively. The corresponding LC50 values toward macrergates were 155.78, 308.38, 75.01, 776.75, and 42.77 mg/kg, respectively. Under field conditions, baits containing 0.2% methanol extract, 0.1% chloroform fraction, and 0.05% isoimperatorin efficiently controlled S. invicta, with effectiveness percentages of 95.56%, 97.78%, and 95.56%, respectively on the 30th day after bait application. Such effectiveness percentages were not significantly different from that obtained using the positive control fipronil. The present study showed that C. virosa L. var. latisecta has potential as a natural control agent for the red imported fire ants
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A regioselectivity switch in Pd-catalyzed hydroallylation of alkynes.
By exploiting the reactivity of a vinyl-Pd species, we control the regioselectivity in hydroallylation of alkynes under Pd-hydride catalysis. A monophosphine ligand and carboxylic acid combination promotes 1,5-dienes through a pathway involving isomerization of alkynes to allenes. In contrast, a bisphosphine ligand and copper cocatalyst favor 1,4-dienes via a mechanism that involves transmetalation. Our study highlights how to access different isomers by diverting a common organometallic intermediate
Constraints on the primordial gravitational waves with variable sound speed from current CMB data
We make a comprehensive investigation of the observational effect of the
inflation consistency relation. We focus on the general single-field inflation
model with the consistency relation , and investigate the
observational constraints of sound speed by using the Seven-Year WMAP
data, the BICEP tensor power spectrum data, and the constraints on and from the Five-Year WMAP
observations. We find that the constraints on the tensor-to-scalar ratio is
much tighter if is small, since a large tilt is strongly
constrained by the observations. We obtain and 0.09 () for =1, 0.1 and 0.01 models at 95.4% confidence level. When taking
smaller values of , the positive correlation between and also
leads to slightly tighter constraint on the upper bound of , while the
running of scalar spectral index is generally unaffected. For the
sound speed , it is not well constrained if only the CMB power spectrum
data is used, while the constraints are obtainable by taking and priors into account. With the
constraining data of and , we
find that, region is excluded at 99.7% CL, and the
case (the single-field slow-roll inflation) is slightly disfavored at 68.3% CL.
In addition, the inclusion of and into the analysis can improve the constraints on and . We
further discuss the implications of our constraints on the test of inflation
models.Comment: 15 pages, 7 figures, updated versio
Shoshonitic enclaves in the high Sr/Y Nyemo pluton, southern Tibet: Implications for Oligocene magma mixing and the onset of extension of the southern Lhasa terrane
Post-collisional potassic and high Sr/Y magmatism in the Lhasa terrane provides critical constraints on the timing and mechanism of subduction of Indian lithosphere and its role in the uplift of the Tibetan Plateau. Here, we report whole-rock geochemistry, mineral geochemistry, zircon U Pb ages, and in situ zircon Hf isotope ratios for the Nyemo pluton, a representative example of such magmatism. The Nyemo pluton is composed of high Sr/Y host rocks and coeval shoshonitic mafic microgranular enclaves (MMEs). Whole-rock compositions of the host rocks and MMEs form linear trends in Harker diagrams, consistent with modification of both end-members by magma mixing. Although the main high Sr/Y phase of the pluton formed by partial melting of the lower crust of the thickened Lhasa terrane, the MMEs display abnormally enriched light rare earth elements, low whole-rock ε_(Nd)(t) and low zircon ε_(Hf)(t) that suggest derivation from low degree melting of hydrous and enriched mantle. Based on the occurrence of shoshonitic magma and high La/Yb and high Sr/Y with adakitic affinity host rocks around 30 Ma, the Nyemo pluton is best explained as a record of onset of extension that resulted from convective removal of the mantle lithosphere beneath Tibet in the Oligocene
Phenomenological Scaling of Rapidity Dependence for Anisotropic Flows in 25 MeV/nucleon Ca + Ca by Quantum Molecular Dynamics Model
Anisotropic flows (, , and ) of light fragments up till
the mass number 4 as a function of rapidity have been studied for 25
MeV/nucleon Ca + Ca at large impact parameters by Quantum
Molecular Dynamics model. A phenomenological scaling behavior of rapidity
dependent flow parameters (n = 1, 2, 3 and 4) has been found as a
function of mass number plus a constant term, which may arise from the
interplay of collective and random motions. In addition, keeps
almost independent of rapidity and remains a rough constant of 1/2 for all
light fragments.Comment: 4 pages, 5 figure
A SIMPLE METHOD FOR MONITORING SPRINGBOARD REACTION FORCE IN GYMNASTIC VAULTING
This work was to found a new method for measuring the reaction force of springboard (BRF), which provides scientific supports to the diagnosis of take-off technique. The elastic moduli of GYMNOVA soft and hard springboards were derived by method of mechanics of material, then the springboards were tested in static, dynamic experiments and computer simulations. An equation with different coefficients for soft and hard spring boards, which describe force-displacement of the springboard, F=kx+cx was obtained and validated. This equation can be used with convenience by employing a high speed camera shooting to the springboard for rapidly monitoring the take-off BRF, and provide scientific supports in the enhancement of vaulting techniques, and in injury preventions as well
The decision optimization of product development by considering the customer demand saturation
Purpose: The purpose of this paper is to analyze the impacts of over meeting customer
demands on the product development process, which is on the basis of the quantitative model
of customer demands, development cost and time. Then propose the corresponding product
development optimization decision.
Design/methodology/approach: First of all, investigate to obtain the customer demand
information, and then quantify customer demands weights by using variation coefficient
method. Secondly, analyses the relationship between customer demands and product
development time and cost based on the quality function deployment and establish
corresponding mathematical model. On this basis, put forward the concept of customer
demand saturation and optimization decision method of product development, and then apply
it in the notebook development process of a company. Finally, when customer demand is
saturated, it also needs to prove the consistency of strengthening satisfies customer demands
and high attention degree customer demands, and the stability of customer demand saturation
under different parameters.
Findings: The development cost and the time will rise sharply when over meeting the
customer demand. On the basis of considering the customer demand saturation, the
relationship between customer demand and development time cost is quantified and balanced. And also there is basically consistent between the sequence of meeting customer demands and
customer demands survey results.
Originality/value: The paper proposes a model of customer demand saturation. It proves the
correctness and effectiveness on the product development decision method.Peer Reviewe
Ethyl 5-(ethoxycarbonyl)-3-(4-methoxyphenyl)-1H-pyrazole-1-acetate
In the title compound, C17H20N2O5, all bond lengths and angles show normal values. The dihedral angle between the pyrazole ring and the benzene ring is 6.98 (11)°. The molecules are linked by intermolecular C—H⋯π interactions
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