850 research outputs found
Biocontrol Potential of Novel Emerging Multiacting Bacterium Bacillus amyloliquefaciens NC6 against Brevicoryne brassicae in Brassica rapa ssp. Pekinensis
The emerging elicitor protein PeBA1, extracted from Bacillus amyloliquefaciens NC6, was tested against the cabbage aphid (Brevicoryne brassicae) for its biocontrol potential. Its effects on the survival, lifespan, immature development, adult reproductive performance, and pest–pathogen interaction were assessed using electrical penetration graphs (EPGs) against B. brassicae. Furthermore, the direct effects of PeBA1 with temperature and climate change in Brassica rapa ssp. Pekinensis plants were investigated by the characterization of active compounds in B. amyloliquefaciens with multi-acting entomopathogenic effects. Compared with controls, PeBA1 treatments decreased (second- and third-generation) B. brassicae population growth rates. In a host selection test, control plants were colonized faster by B. brassicae than PeBA1-treated B. rapa plants. The B. brassicae nymphal development was extended by PeBA1 concentrations. Likewise, fecundity was reduced in PeBA1-treated seedlings compared with control, with fewer offspring produced. The trichomes and wax production on PeBA1-treated leaves resulted in a hostile environment for B. brassicae. PeBA1 altered the surface structure of the leaves, reducing B. brassicae reproduction and preventing colonization. Systemic defensive processes also included the activation of pathways (JA, SA, and ET). Based on these findings against B. brassicae, integrated pest management and bio control with PeBA1 in the agroecosystem appears to be suitabl
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Origin of the ungrouped achondrite NWA 4518: mineralogy and geochemistry of FeNi-metal
Ungrouped achondrite NWA 4518 is an ultramafic breccia with abundant siderophile rich IIA-like metal. Its silicate chemistry is similar to that of WINs, HEDs, and silicate inclusions of IIE irons. Oxygen isotopic composition is nearby IAB-IIICD-WIN
The Economic Ramifications of Strategic IT Security Information Sharing in the Financial Services Industry
We investigate the economic ramifications of strategic IT security information sharing among firms in the financial services industry. An IT security information sharing system can potentially minimize security breaches. However, although the Presidential Decision Directive/NSC-63 encouraged the establishment of such a system in the form of industry based information sharing and analysis centers (ISACs), it is injudicious to assume that firms will be willing to naively share their security information with their strategic competitors. We argue that without a proper mechanism some firms will try to put in minimum effort, potentially reducing the system’s reliability, and aim to answer the following research question: “What will it take for a financial services firm to willingly share its strategic information technology security information with its competitors through an ISAC?” We use the theory of mechanism design in economics to develop an adverse selection model to address the question
Chalcophile Element Constraints on the Sulfur Content of the Martian Mantle
The sulfur content of the Martian mantle is critical to understanding volcanic volatiles supplied to the surface of Mars and possibly climate. In the absence of Martian mantle rocks, sulfur content of the mantle has been inferred from S contents of Martian meteorites or from sedimentary sulfate abundances. Estimates of the sulfur content of the Martian mantle vary from 390-2,000 ppm, all of which are higher than that of the terrestrial mantle (~250 ppm;). Residual sulfide in the Martian mantle controls the distribution of chalcophile elements during partial melting. In this study, we report new analyses of Martian meteorites, and use the incompatible behavior of As, Tl and Pb to infer the sulfide mode of the Martian mantle using a different set of assumptions than those of prior studies
Tin Abundances Require that Chassignites Originated from Multiple Magmatic Bodies Distinct from Nakhlites
Meteorites from Mars lack field context but chemical and chronologic studies have revealed remarkable links between nakhlites and chassignites. A widely held consensus is that nakhlites and chassignites originated from a large, single differentiated flow or shallow intrusive [1-5]. An Ar-Ar study assumed multiple flows based on resolvable age differences between meteorites [6], but did not address the possibility of differential cooling in a large, shallowly emplaced intrusion [1]. REE abundances in pyroxenes from nakhlites and Chassigny led [7] to argue for derivation of these rocks from distinct magmas. Volatile abundances (F, Cl, OH) in chlorapatites indicated that the entire suite of nakhlites and chassignites experienced hydrothermal interaction with a single fluid supporting a single body origin [4]. The discovery of a new chassignite, NWA 8694, extended the Mg# range from 80-54, providing a closer link to nakhlites but revealed the petrological difficulty of fractionating a single body of liquid to yield a series of olivine cumulates with such a large Mg# range [8]. When mafic magmas are emplaced into the crust, crustal assimilation can impart distinct elemental signatures if the country rock has experienced sedimentary or hydrothermal processing [9]. In this work, we used Sn abundances of nakhlites and chassignites to show that these rocks were crystallized from distinct magma batches, providing vital contextual clues to their origin
Minimization of Threshold-Current Dependence of Quantum Dot Laser Using InN
This paper focuses on the effect of threshold current density on different characteristics of quantum dot based laser. To investigate the effect, different characteristics have been analyzed using quantum dot as the active layer material of the laser structure. Performance improvement of quantum dot laser using InN has been achieved in terms of minimization of the threshold current dependence such as mirror loss, modal gain, turn-on delay and so forth. Numerical results have been analyzed considering the values of threshold current densities of GaN, AlN and InN based quantum dot lasers. Analytical results show that internal loss increases linearly with the increase of the threshold current density. However, other characteristics like mirror loss, modal gain, turn-on delay have nonlinear dependence on the threshold current density for any material used in the active layer. The threshold current density of InN quantum dot based laser is lower than that of other existing quantum dot based lasers. Analytical results ascertained that mirror loss has been increased a little bit. Conversely, internal loss and modal gain have been minimized considerably using InN based quantum dot in the active layer of the laser structure. In addition, turn-on delay time has been also minimized significantly
Rethinking FS-ISAC: An IT Security Information Sharing Network Model for the Financial Services Sector
This study examines a critical incentive alignment issue facing FS-ISAC (the information sharing alliance in the financial services industry). Failure to encourage members to share their IT security-related information has seriously undermined the founding rationale of FS-ISAC. Our analysis shows that many information sharing alliances’ membership policies are plagued with the incentive misalignment issue and may result in a “free-riding” or “no information sharing” equilibrium. To address this issue, we propose a new information sharing membership policy that incorporates an insurance option and show that the proposed policy can align members’ incentives and lead to a socially optimal outcome. Moreover, when a transfer payment mechanism is implemented, all member firms will be better off joining the insurance network. These results are demonstrated in a simulation in which IT security breach losses are compared both with and without participating in the proposed information sharing insurance plan
Modeling and Analysis of a Cascaded Battery-Boost Multilevel Inverter Using Different Switching Angle Arrangement Techniques
Multilevel inverters have the capability to produce an AC staircase output waveform without using a bulky passive filter. Therefore, the multilevel inverters are gaining more and more popularity, among the different types of inverters, for photovoltaic applications in the modern era of technology. However, if the switching angle arrangement technique is not selected appropriately then the total harmonic distortion of the voltage output waveform may become undesirable. In this paper, Half-Equal-Phase, Feed-Forward and Selective Harmonics Elimination Pulse Width Modulation switching angle arrangement techniques at different power factors (i.e., 1.0, 0.75 and 0.50) are applied to a cascaded battery-boost inverter. PSIM software is used to evaluate and compare the performance of a 9-level cascaded battery-boost inverter with three switching angle arrangement techniques at power factors of 1.0, 0.75, and 0.50, respectively. Simulation results show that the Selective Harmonics Elimination Pulse Width Modulation technique can produce an output voltage and current waveform with the lowest total harmonic distortion. On the other hand, the output current waveform produced by power factor 0.50 had the lowest total harmonic distortion
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