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

Siderophile Element Constraints on the Conditions of Core Formation in Mars

Siderophile element concentrations in planetary basalts and mantle samples have been used to estimate conditions of core formation for many years and have included applications to Earth, Moon, Mars and asteroid 4 Vesta [1]. For Earth, we have samples of mantle and a diverse collection of mantle melts which have provided a mature understanding of the how to reconstruct the concentration of siderophile elements in mantle materials, from only concentrations in surficial basalt (e.g., [2]). This approach has led to the consensus views that Earth underwent an early magma ocean stage to pressures of 40-50 GPa (e.g., [3,4]), Moon melted extensively and formed a small (approx. 2 mass %) metallic core [5], and 4 Vesta contains a metallic core that is approximately 18 mass % [6,7]. Based on new data from newly found meteorites, robotic spacecraft, and experimental partitioning studies, [8] showed that eight siderophile elements (Ni, Co, Mo, W, Ga, P, V and Cr) are consistent with equilibration of a 20 mass% S-rich metallic core with the mantle at pressures of 14 +/- 3 GPa. We aim to test this rather simple scenario with additional analyses of meteorites for a wide range of siderophile elements, and application of new experimental data for the volatile siderophile and highly siderophile elements

Effect of Pressure on the Activity Coefficients of Au and Other Siderophile Elements in Liquid Fe-Si Alloys

Light elements can alloy into the iron cores of terrestrial planetary bodies. It is estimated that the Earths core contains ~10% of a light element, most likely a combination of S, C, Si, and O with Si probably being the most abundant. Si dissolved into Fe metal liquids can have a significant influence on the activity coefficients of siderophile elements, and thus the partitioning behavior of those elements between the core and mantle. Many of these elements have been investigated extensively at ambient pressure, and studies up to 1 GPa are becoming more common, but few have been studied at pressures above this. The formation of the Earths core has been estimated to have formed at pressures between 40-60 GPa, so investigating the effect pressure has on Sis influence on siderophile element partitioning is important for modeling core formation in the Earth and smaller planets. Pressure is well known to influence volumetric properties of metallic and silicate liquids, and oxygen fugacity (e.g., [10,11]), but less is known about its effect on activity coefficients (e.g., [12]). Some activity coefficients depend strongly upon the Si content of Fe liquids, and the concentration of siderophile elements such as P, Sb, and As in the terrestrial mantle is easily influenced by dissolved Si in the core. Thus, isolating the effect of pressure on activity coefficients in general is critical in quantitative analysis of core formation models. In this work, we investigate the effect variable Si content has on the partitioning of Au between Fe metal and silicate melt at 10 GPa and 2373 K, with the intention of comparing the behavior to that already investigated at lower pressures. In addition, P, V, Mn, Ga, Zn, Cd, Sn, W, Pb, and Nb were also measured and could thus be included in the assessment of potential pressure effects

Highly Siderophile Elements in Pallasites and Diogenites, Including the New Pallasite, CMS 04071

Pallasites are long thought to represent a metallic core-silicate mantle boundary, where the IIIAB irons are linked to the crystallization history of the metallic fraction, and the HED meteorites may be linked to the silicate fraction. However, measurement of trace elements in individual metallic and silicate phases is necessary in order to fully under-stand the petrogenetic history of pallasites, as well as any magmatic processes which may link pallasites to both IIIAB irons and HED meteorites. In order to achieve this objective, abundances of a suite of elements were measured, including the highly siderophile elements (HSEs), in kamacite, taenite, troilite, schreibersite, chromite and olivine for the pallasites Admire, Imilac, Springwater, CMS 04071. In the diogenites GRO 95555, LAP 91900, and MET 00436, metal, sulfide, spinel, pyroxene, and silica were individually measured

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

Effect of Silicon on the Activity Coefficient of Rhenium in Fe-Si Liquids: Implications for HSE and Os Isotopes in Planetary Mantles

Metallic cores contain light alloying elements that can be a combination of S, C, Si, and O, all of which have important chemical and physical influences. For Earth, Si may be the most abundant light element in the core. Si dissolved into Fe liquids can have a large effect on the magnitude of the activity coefficient of siderophile elements (SE), and thus the partitioning behavior of those elements between core and mantle. The effect of Si on the highly siderophile elements is only beginning to be studied and the effects on Au, Pd and Pt are significant. Here we report new experiments designed to quantify the effect of Si on the partitioning of Re between metal and silicate melt. A solid understanding of Re partitioning is required for a complete understanding of the Re-Os isotopic systems. The results will be applied to understanding the HSEs and Os isotopic data for planetary mantles, and especially Earth

Partitioning of Pd Between Fe-S-C and Mantle Liquids at High Pressure and Temperature: Implications for Core Formation

One of the most elusive geochemical aspects of the early Earth has been explaining the near chondritic relative abundances of the highly siderophile elements (HSE; Au, Re and the platinum group elements) in Earth's primitive upper mantle (PUM). Perhaps they were delivered to the Earth after core formation, by late addition of carbonaceous chondrite material. However, the recognition that many moderately siderophile elements can be explained by high pressure and temperature (PT) metal-silicate equilibrium, leads to the question whether high PT equilibrium can also explain the HSE concentrations. Answers to this question have been slowed by experimental difficulties (nugget effect and very low solubilities). But two different perspectives have emerged from recent studies. One perspective is that D(M/S) for HSE at high PT are not low enough to explain terrestrial mantle depletions of these elements (for Pd and Pt). A second perspective is D(M/S) are reduced substantially at high PT and even low enough to explain terrestrial mantle depletions (for Au and Pt). Issues complicating interpretation of all experiments include use of MgO- and FeO-free silicate melts, and S-free and FeNi metal-free systems. In addition, conclusions for Pt rest on an interpretation that the tiny metallic nuggets plaguing many such experiments, were formed upon quench. There is not agreement on this issue, and the general question of HSE solubility at high PT remains unresolve

Apatite/Melt Partitioning Experiments Reveal Redox Sensitivity to Cr, V, Mn, Ni, Eu, W, Th, and U

Apatite is a common mineral in terrestrial, planetary, and asteroidal materials. It is commonly used for geochronology (U-Pb), sensing volatiles (H, F, Cl, S), and can concentrate rare earth elements (REE) during magmatic fractionation and in general. Some recent studies have shown that some kinds of phosphate may fractionate Hf and W and that Mn may be redox sensitive. Experimental studies have focused on REE and other lithophile elements and at simplified or not specified oxygen fugacities. There is a dearth of partitioning data for chalcophile, siderophile and other elements between apatite and melt. Here we carry out several experiments at variable fO2 to study the partitioning of a broad range of trace elements. We compare to existing data and then focus on several elements that exhibit redox dependent partitioning behavior

Osmium Isotope Systematics of Ureilites

The Os-187/Os-188 for twenty-two ureilite whole rock samples, including monomict, augite-bearing, and polymict lithologies, were examined in order to constrain the provenance and subsequent magmatic processing of the ureilite parent body (or bodies). The Re/Os ratios of most ureilites show evidence for a recent disturbance, probably related to Re mobility during weathering, and no meaningful chronological information can be extracted from the present data set. The ureilite Os-187/Os-188 ratios span a range from 0.11739 to 0.13018, with an average of 0.1258+/-0.0023 (1(sigma)), similar to typical carbonaceous chondrites, and distinct from ordinary or enstatite chondrites. The similar mean of Os-187/Os-188 measured for the ureilites and carbonaceous chondrites suggests that the ureilite parent body probably formed within the same region of the solar nebula as carbonaceous chondrites. From the narrow range of the 187Os/188Os distribution in ureilite meteorites it is further concluded that Re was not significantly fractionated from Os during planetary differentiation and was not lost along with the missing ureilitic melt component. The lack of large Re/Os fractionations requires that Re/Os partitioning was controlled by a metal phase, and thus metal had to be stable throughout the interval of magmatic processing on the ureilite parent body

Phase Ordering Dynamics of ϕ4\phi^4 Theory with Hamiltonian Equations of Motion

Phase ordering dynamics of the (2+1)- and (3+1)-dimensional $\phi^4$ theory with Hamiltonian equations of motion is investigated numerically. Dynamic scaling is confirmed. The dynamic exponent $z$ is different from that of the Ising model with dynamics of model A, while the exponent $\lambda$ is the same.Comment: to appear in Int. J. Mod. Phys.