Lateral Density Research Articles

Solutions for Subtidal Flow in Channels and Estuaries Under Different Integral Constraints

AbstractThis study builds on Huntley and Ryan (2018, https://doi.org/10.1002/2017JC012748) and related prior works on channels and estuaries by considering solutions for the same subtidal dynamics but with alternative integral flow constraints. Prior solutions do not have a truly two‐dimensional (2‐D) flow field, as axial changes in the axial flow are implied. Three constraint types are considered: the Constant case with spatially constant density gradients constrained with section‐integrated flow (as in prior works), Semi‐Variable case with a constant axial density gradient and laterally variable lateral density gradient constrained with depth‐integrated lateral flow, and Variable case with spatially variable density gradients in both directions constrained with depth‐integrated axial and lateral flows. The Semi‐Variable and Variable cases can produce solutions with truly 2‐D flow if the depth‐integrated lateral flow is set to zero everywhere. Differences among solutions are illustrated with idealized and realistic applications from Huntley and Ryan (2018, https://doi.org/10.1002/2017JC012748). For the idealized application, the Constant case and the Semi‐Variable case with 2‐D flow have clear differences in axial velocity and stark contrasts in lateral flow (and density gradients). For the Nares Strait application, the Variable case with observed depth‐averaged axial and lateral velocities is best able to represent the fastest observed down‐channel velocities, the weak reversed flow on one side of the channel, and the observed lateral flow structure. Overall, selecting different integral constraints on flow conspicuously changes the subtidal flow, opens up new possibilities for truly 2‐D flow solutions, and provides additional flexibility for representing observed conditions in realistic situations.

Sound pulses in lipid membranes and their potential function in biology

Experimental observations in lipid monolayers at the air-water interface have demonstrated that solitary sound pulses can be excited. These pulses propagate electrical, chemical, and thermal variations in addition to the mechanical changes in lateral pressure and lipid density, and can interact with nearby ions, polymers, and water. In addition, it was demonstrated that sound pulses that reversibly traverse the melting transition between the so-called liquid-expanded and liquid-condensed phases display unusual nonlinear properties that are strikingly similar to those of action potentials in living cells. This review describes recent experimental and theoretical investigations of sound in lipid membranes and their potential function in biology.

Thermally stimulated dislocation generation in silicon crystals grown by the Float-Zone method

Based on own previous studies on dislocation generation in FZ- silicon crystals and in order to verify the location and conditions of dislocation generation and spreading, in the current work we present results from a model experiment using a measurement set-up close to the FZ process. Here, an as-grown dislocation-free FZ crystal with a diameter of 20 mm was exposed to temperature-induced strains. No mechanical surface treatment or sample preparation were applied and no mechanical stress was induced during measurement. The crystal was stepwise heated up in the temperature range from 700 °C till 1180 °C controlled by a pyrometric system. The crystal was cut into several samples and analyzed by Lateral Photovoltage Scanning (LPS), photoluminescence (PL) and etch pit density (EPD) as well as the lifetime (MDP) were measured. Our experimental results show that there is an indication that the dislocation density and the lifetime show an inverse behavior depending on the temperature increase in the investigated range. Therefore, this basic correlation known from the literature was confirmed. The area of dislocations generation and its spreading behavior could be revealed. Possible origins and correlations are discussed.

The gravimetric contribution to the Moho estimation in the presence of vertical density variations

The Moho surface, namely the density discontinuity between crust and mantle, is traditionally studied by seismic methods. However, gravity information can contribute to the Moho estimation and, more generally, to the crustal modeling. The contribution is twofold. First, gravimetry generally provides observations with much lower errors than those implied by the mass density uncertainty and other geophysical assumptions. This means that it can be used to validate existing Moho and/or crustal models by forward modeling. Second, gravity inversion is able to provide diffused (not localized) information on the mass distribution, both regionally and globally (thanks to dedicated satellite gravity missions). However, this information is weak due to its intrinsic ill-posedness. This means that it can be used to correct and spatially interpolate existing models, and to complement seismic, magnetic and geological information to create new models. In this work, the problem of estimating the Moho surface by gravity inversion assuming a two-layer model with lateral and vertical density variations is treated at a regional level. The approach consists in linearizing the forward modeling around a reference Moho at a constant depth and then inverting it through a Wiener filter. This is standard in case of two layers with homogeneous density distributions (or with lateral density variations), while it requires some additional considerations and algorithm modifications in case of vertical density variations. The basic idea is to “condensate” the masses inside the Moho undulation on the reference surface used for the linearization, thus requiring the setup of an iterative procedure. A strategy to introduce seismic information into this inversion procedure is proposed too, with the aim of improving the a priori density modeling. A closed loop test is presented for the algorithm assessment, showing the improvement with respect to a standard approach and the capability of the proposed algorithm to reconstruct the originally simulated Moho undulation by also fitting the gravity and seismic data at a level that is consistent with their observation noise.

Lateral Circulation and Associated Sediment Transport in a Convergent Estuary

AbstractThe Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST) modeling system was used to explore lateral circulation and associated sediment transport in a convergent estuary with existence of channel and shoals. The lateral momentum balance was found to be largely geostrophic with a barotropic pressure gradient balanced by a baroclinic pressure gradient and Coriolis forcing during most time of a tidal cycle, except at the maximum ebb/flood. At the east side (right side looking landward), due to estuarine convergence, barotropic forcing strongly modulates lateral momentum balance and generates eastward residual sediment transport during spring tides. But during neap tides, the enhanced lateral density gradient induces strong lateral baroclinic forcing to cause westward residual sediment flux. At the west side, baroclinic forcing strongly influences the lateral momentum balance and generates westward sediment transport. Together, lateral circulation tends to distribute sediment from the channel to both the side shoals during spring tides but generates westward sediment flux during neap tides. The diagnostic analysis of the lateral gradient of suspended sediment concentration (SSC) demonstrates that lateral sediment trapping is strongly influenced by the lateral circulation and the lateral asymmetry in bed erosion during spring tides, whereas lateral advection becomes the controlling factor during neap tides. Mechanisms for the lateral circulation and sediment transport can be extended to other convergent estuaries.

Exogenous Carbon Compounds Modulate Tomato Root Development.

NO3− is not only a nutrient, but also a signaling compound that plays an important role in several plant processes, like root development. The present study aimed to investigate the effect of three different exogenous C compounds (sucrose, glucose, 2-oxoglutarate) added to NO3− nutrition on C/N, auxin and antioxidant metabolisms in 10-day-old tomato seedlings. Sucrose and glucose supplementation enhanced primary root (PR) length, lateral root number and root density, while 2-oxoglutarate negatively affected them. This phenomenon was accompanied by a slight increase in NRT2.1 and GS1 gene expression, together with an increase in LAX2 and LAX3 and a decrease in LAX4 in the roots growing under sucrose and glucose sources. The addition of 2-oxoglutarate enhanced the expression of NiR, GDH, PEPC1, LAX1, LAX3 and the antioxidant gene SOD Cl. Taken together, these findings contribute to a better understanding of how these C sources can modulate N uptake and C/N, auxin and antioxidant gene expression, which could be useful for improving nitrogen use efficiency.

Profiling float observation of thermohaline staircases in the western Mediterranean Sea and impact on nutrient fluxes

Abstract. In the western Mediterranean Sea, Levantine intermediate waters (LIW), which circulate below the surface productive zone, progressively accumulate nutrients along their pathway from the Tyrrhenian Sea to the Algerian Basin. This study addresses the role played by diffusion in the nutrient enrichment of the LIW, a process particularly relevant inside step-layer structures extending down to deep waters – structures known as thermohaline staircases. Profiling float observations confirmed that staircases develop over epicentral regions confined in large-scale circulation features and maintained by saltier LIW inflows on the periphery. Thanks to a high profiling frequency over the 4-year period 2013–2017, float observations reveal the temporal continuity of the layering patterns encountered during the cruise PEACETIME and document the evolution of layer properties by about +0.06 ∘C in temperature and +0.02 in salinity. In the Algerian Basin, the analysis of in situ lateral density ratios untangled double-diffusive convection as a driver of thermohaline changes inside epicentral regions and isopycnal diffusion as a driver of heat and salt exchanges with the surrounding sources. In the Tyrrhenian Sea, the nitrate flux across thermohaline staircases, as opposed to the downward salt flux, contributes up to 25 % of the total nitrate pool supplied to the LIW by vertical transfer. Overall, however, the nutrient enrichment of the LIW is driven mostly by other sources, coastal or atmospheric, as well as by inputs advected from the Algerian Basin.

The usefulness of trabecular bone score in patients with ankylosing spondylitis.

Backgrounds/AimsThis study was performed to reveal the usefulness of the trabecular bone score (TBS) in assessing bone strength in patients with ankylosing spondylitis (AS) in comparison with dual-energy X-ray absorptiometry (DXA) methods.MethodsA total of 215 AS patients (75.8% male) were enrolled from a single university hospital in Korea. Demographic and clinical information were assessed. Patients completed X-rays of the cervical and lumbar spine (L-spine), and spinal ankyloses were quantified using the modified Stoke AS Spine Score (mSASSS). Hip, anteroposterior and lateral L-spine bone mineral density (BMD) and TBS were assessed by DXA methods. Clinical characteristics and bone strength measurement results were compared between male and female AS patients. The accuracy of each bone strength evaluation method in predicting Fracture Risk Assessment Tool (FRAX) scores indicating moderate or higher fracture risk was compared by receiver operating characteristic curves in patients aged ≥ 40 years. Correlations between each bone strength measurement method and mSASSS were examined.ResultsMale patients showed higher mSASSS and less prevalent peripheral joint involvement compared to female patients (p < 0.05). TBS, hip BMD, and L-spine lateral BMD showed comparably high areas under the curve (AUCs) for predicting FRAX-major osteoporotic fractures (MOF) ≥ 10% (AUC ranged 0.72 to 0.76). TBS negatively correlated with mSASSS in both male and female patients (p < 0.01).ConclusionsTBS could predict the risk of MOF and is not influenced by spinal osteoproliferation in AS patients, even in those with advanced spinal changes.

Thermal Responses to Antarctic Ice Shelf Melt in an Eddy-Rich Global Ocean–Sea Ice Model

AbstractThe response of near-Antarctic waters to freshening by increased glacial melt is investigated using a high-resolution (0.1°) global ocean–sea ice model with realistic Antarctic water-mass properties. Two meltwater perturbation experiments are conducted where the ocean model is forced with constant elevated glacial melt rates of 1.5 and 2.8 times the control rate. Within 10 years of the onset of enhanced meltwater forcing, the generation of Antarctic Bottom Water from Dense Shelf Water ceases, as shelf waters become increasingly buoyant. Increased ocean stratification triggers subsurface warming in Dense Shelf Water source regions, suggesting a localized positive feedback to melt. In a parallel response, meltwater forcing enhances the subsurface lateral density gradients of the Antarctic Slope Front that modulate the transport of warm Circumpolar Deep Water across the continental slope toward ice shelf grounding lines. Consequently, coastal freshening acts to isolate the Antarctic Ice Sheet from open ocean heat, suggesting a cooling response to melt that counteracts warming associated with stratification. Further, these strengthening density gradients accelerate westward geostrophic currents along the coast and shelf break, homogenizing shelf waters and amplifying remote feedbacks. The net effect on the continental shelf is transient warming, followed by cooling in both experiments; however, this signal is the aggregate of a complex pattern of regional warming and cooling responses. These results suggest coastal freshening by meltwater may alter the thermal forcing of the Antarctic ice sheet in ways that both accelerate and inhibit ice shelf melt at different locations along the Antarctic coastline.

The platform GrowScreen-Agar enables identification of phenotypic diversity in root and shoot growth traits of agar grown plants

BackgroundRoot system architecture and especially its plasticity in acclimation to variable environments play a crucial role in the ability of plants to explore and acquire efficiently soil resources and ensure plant productivity. Non-destructive measurement methods are indispensable to quantify dynamic growth traits. For closing the phenotyping gap, we have developed an automated phenotyping platform, GrowScreen-Agar, for non-destructive characterization of root and shoot traits of plants grown in transparent agar medium.ResultsThe phenotyping system is capable to phenotype root systems and correlate them to whole plant development of up to 280 Arabidopsis plants within 15 min. The potential of the platform has been demonstrated by quantifying phenotypic differences within 78 Arabidopsis accessions from the 1001 genomes project. The chosen concept ‘plant-to-sensor’ is based on transporting plants to the imaging position, which allows for flexible experimental size and design. As transporting causes mechanical vibrations of plants, we have validated that daily imaging, and consequently, moving plants has negligible influence on plant development. Plants are cultivated in square Petri dishes modified to allow the shoot to grow in the ambient air while the roots grow inside the Petri dish filled with agar. Because it is common practice in the scientific community to grow Arabidopsis plants completely enclosed in Petri dishes, we compared development of plants that had the shoot inside with that of plants that had the shoot outside the plate. Roots of plants grown completely inside the Petri dish grew 58% slower, produced a 1.8 times higher lateral root density and showed an etiolated shoot whereas plants whose shoot grew outside the plate formed a rosette. In addition, the setup with the shoot growing outside the plate offers the unique option to accurately measure both, leaf and root traits, non-destructively, and treat roots and shoots separately.ConclusionsBecause the GrowScreen-Agar system can be moved from one growth chamber to another, plants can be phenotyped under a wide range of environmental conditions including future climate scenarios. In combination with a measurement throughput enabling phenotyping a large set of mutants or accessions, the platform will contribute to the identification of key genes.

The Presence of Plant-Associated Bacteria Alters Responses to N-acyl Homoserine Lactone Quorum Sensing Signals that Modulate Nodulation in Medicago Truncatula.

Bacteria use quorum sensing signaling for cell-to-cell communication, which is also important for their interactions with plant hosts. Quorum sensing via N-acyl-homoserine lactones (AHLs) is important for successful symbioses between legumes and nitrogen-fixing rhizobia. Previous studies have shown that plant hosts can recognize and respond to AHLs. Here, we tested whether the response of the model legume Medicago truncatula to AHLs from its symbiont and other bacteria could be modulated by the abundance and composition of plant-associated microbial communities. Temporary antibiotic treatment of the seeds removed the majority of bacterial taxa associated with M. truncatula roots and significantly altered the effect of AHLs on nodule numbers, but lateral root density, biomass, and root length responses were much less affected. The AHL 3-oxo-C14-HSL (homoserine lactone) specifically increased nodule numbers but only after the treatment of seeds with antibiotics. This increase was associated with increased expression of the early nodulation genes RIP1 and ENOD11 at 24 h after infection. A 454 pyrosequencing analysis of the plant-associated bacteria showed that antibiotic treatment had the biggest effect on bacterial community composition. However, we also found distinct effects of 3-oxo-C14-HSL on the abundance of specific bacterial taxa. Our results revealed a complex interaction between plants and their associated microbiome that could modify plant responses to AHLs.

Ductile nappe extrusion in constrictive strain at the origin of transverse segments of the Allochthon Boundary Thrust in the Manicouagan Imbricate Zone (Central Grenville Province, Québec)

Separating the Parautochthonous and Allochthonous belts, the Allochthon Boundary Thrust (ABT) is a major lithotectonic boundary that generally runs parallel with the length of the Grenville Province, but with some transverse segments. In this contribution, we investigate one of these segments, the Manicouagan Imbricate Zone (MIZ), by adding new field-based data supplemented by new U–Pb deformation ages to a compilation of previous research conducted on both sides of the ABT in the region. Our results reveal striking differences between the footwall and hanging wall of the ABT in terms of strain and structures and concludes that the transverse orientation of the ABT is not related to folding. An updated strain analysis allows us to determine that deformation of the MIZ was dominated by a constrictive-type of strain. We build on a previously proposed conceptual model to document ductile extrusion over basement ramps driven by tectonic forcing and lateral density contrast in the upper crust at ca. 990 Ma. The insertion of the hot ductile nappe into partially molten metasediments of the surrounding Parautochthonous Belt was accommodated by constrictive strain within the former and flattening and transverse folding in the latter.

Oral bisphosphonate treatment in patients with Duchenne muscular dystrophy on long term glucocorticoid therapy

Osteoporosis is a major problem in patients with Duchenne muscular dystrophy (DMD), due to glucocorticoid therapy and muscle weakness. Evidence on which to base optimal prevention and treatment strategies, including bisphosphonate use, in DMD are limited. Our objective was to describe bone health outcomes of oral alendronate treatment in patients with DMD and glucocorticoid-induced osteoporosis. We retrospectively studied 54 patients treated between 2005 and 2017, and assessed changes in dual-energy x-ray absorptiometry (DXA) whole body and lumbar spine bone mineral density and content, and lateral distal femur bone mineral density. We also examined vertebral fracture development in a subset with serial spine radiographs. Pre-alendronate DXA Z-score trajectories decreased progressively. Over three years post-alendronate initiation, Z-score trajectories improved (p<0.01) at most sites compared with pre-alendronate trajectories. Height-adjusted Z-score trajectories for lumbar spine bone mineral density (p = 0.01) and whole body bone mineral content (p = 0.0004) also improved. The positive trajectories did not seem to be sustained long term in those treated up to 6 years. Radiographic vertebral findings in 43 patients appeared stable. In conclusion, oral bisphosphonate therapy using alendronate was associated with improvement of DXA bone health indices during the first three years of treatment, and may help mitigate progression of osteoporosis in glucocorticoid-treated patients with DMD.

A practical characterisation protocol for liquid-phase synthesised heterogeneous graphene

We demonstrate a characterisation protocol for quantifying nanostructural features associated with heterogeneous graphene nanosheets, including the lateral dimension, thickness and defect density of flakes produced by liquid phase exfoliation methods. The underlying basis for the protocol is a cross correlation between high resolution electron probe-based techniques and lower resolution but higher throughput photon probe-based characterisation methods. Using statistical data analysis we are able to develop a practical characterisation protocol that provides access to the precision and accuracy of the various graphene characterisation techniques. We have shown that the lateral dimension and thickness of heterogeneous graphene flakes can be rapidly quantified via optical mapping techniques. The defect densities within graphene samples can be accessed via Raman micro-spectroscopy. Based on the high throughput photon probe-based characterisation method, statistically representative data for heterogeneous graphene nanosheets can be obtained. Such information can be used to differentiate between inhomogeneous graphene samples in large length scales and thus can be useful for optimising graphene synthesis processes.

Enhanced magnetization of ultrathin NiFe2O4 films on SrTiO3(001) related to cation disorder and anomalous strain

NiFe$_2$O$_4$ thin films with varying thickness were grown on SrTiO$_3$(001) by reactive molecular beam epitaxy. Soft and hard x-ray photoelectron spectroscopy measurements reveal a homogeneous cation distribution throughout the whole film with stoichiometric Ni:Fe ratios of 1:2 independent of the film thickness. Low energy electron diffraction and high resolution (grazing incidence) x-ray diffraction in addition to x-ray reflectivity experiments were conducted to obtain information of the film surface and bulk structure, respectively. For ultrathin films up to 7.3 nm, lateral tensile and vertical compressive strain is observed, contradicting an adaption at the interface of NiFe$_2$O$_4$ film and substrate lattice. The applied strain is accompanied by an increased lateral defect density, which is decaying for relaxed thicker films and attributed to the growth of lateral grains. Determination of cationic site occupancies in the inverse spinel structure by analysis of site sensitive diffraction peaks reveals low tetrahedral occupancies for thin, strained NiFe$_2$O$_4$ films, resulting in partial presence of deficient rock salt like structures. These structures are assumed to be responsible for the enhanced magnetization of up to $\sim$250\% of the NiFe$_2$O$_4$ bulk magnetization as observed by superconducting quantum interference device magnetometry for ultrathin films below 7.3 nm thickness.

Soft Polymer Janus Nanoparticles at Liquid–Liquid Interfaces

AbstractSoft polymeric Janus nanoparticles (JNPs), made from polystyrene‐b‐poly(butadiene)‐b‐poly(methylmethacrylate), PS‐PB‐PMMA, triblock terpolymers, assemble into a monolayer at the water–oil interface to reduce interfacial tension. The extent to which the polymer chains can deform influences the packing density of the JNPs at the interface. The longer the polymer chains are relative to the core, the softer are the JNPs, resulting in a JNPs assembly with a lower initial lateral packing density. The interfacial activity of JNPs can be further tuned by complexation of the PMMA chains with lithium ions that are introduced into the water phase. This work provides a fundamental understanding of soft JNPs packing at the water–oil interface and provides a strategy to tailor the areal density of soft JNPs at liquid–liquid interface, enabling the design of smart responsive structured‐liquid systems.

Soft Polymer Janus Nanoparticles at Liquid–Liquid Interfaces

Soft polymeric Janus nanoparticles (JNPs), made from polystyrene-b-poly(butadiene)-b-poly(methylmethacrylate), PS-PBPMMA, triblock terpolymers, assemble into a monolayer at the water/oil interface to reduce interfacial tension. The extent to which the polymer chains can deform, influences the packing density of the JNPs at the interface. The longer the polymer chains are relative to the core, the softer are the JNPs, resulting in a JNPs assembly with a lower initial lateral packing density. The interfacial activity of JNPs can be further tuned by complexation of the PMMA chains with lithium ions that are introduced into the water phase. This work provides a fundamental understanding of soft JNPs packing at the water/oil interface and provides a strategy to tailor the areal density of soft JNPs at liquid/liquid interface, enabling the design of smart responsivestructured-liquid systems.

Potential deep-buried petroleum systems in Meso-Neoproterozoic rifts of the southwestern North China Craton revealed by gravity anomalies

In order to evaluate the potential petroleum system within the Meso-Neoproterozoic strata of the southwest North China Craton (NCC), we explored the deep-buried basal tectonics on the Precambrian basement and the residual sedimentary thickness of the Meso-Neoproterozoic in the Ordos Basin. A combination of geophysical processing methodologies has been conducted. Based on regional seismic exploration, the shallow gravity effects caused by the undulation of the Cenozoic, Jurassic, Carboniferous and Cambrian sedimentary formations were calculated through forward modeling, and eliminated the free-air gravity anomaly by a gravity stripping technique. Subsequently, by using the wavelet multi-scale decomposition method, the deeper gravity effect sourcing from underneath the Meso-Neoproterozoic base was calculated and then eliminated, including the undulation of Paleoproterozoic-Archaean crystalline basement and the lateral density discontinuity of the lower crust. As a result, the residual gravity anomalies caused by the Meso-Neoproterozoic sedimentary formations and the Moho discontinuity of the Ordos Block were both obtained, which was then used for inversion. The inversion results show that the residual Meso-Neoproterozoic strata are mainly distributed in the southwest and northern part of the Ordos Block, and the Moho depth of the Ordos Block averages about 42 km. It ranges from 38 to 42 km in the eastern part and deepens to over 44 km in the west. In addition, there are some detailed deep-structure reflections on the Moho discontinuity. For instance, the parallel-arranged NE-trending anomalous belts in southwest Ordos Block indicate strong crustal extension and mantle uplift. The regional geology indicates that the NE-trending crustal extension is not related to the Cenozoic strike-slip pull-apart process around the Ordos Block, nor the Indosinian Movement in Early Mesozoic, or the cratonic depression in the Paleozoic. However, it highly resembles the NE-oriented paleo-rifts that developed in the Meso-Neoproterozic aulacogens. The residual crustal gravity anomaly eliminates both the shallow disturbance from the sediments and the deep shadow from the mantle. It shows very good consistency with the undulation of the Meso-Neoproterozoic sedimentary basement along a classical interpreted seismic survey line, which validates the correlation between the NE-trending anomalous belts with the basal aulacogen tectonics. According to seismic interpretation, the paleo-rifts within the Precambrian aulacogens occurred during the Mesoproterozoic and continued into the early Neoproterozoic. Huge volumes of sediment filled the rift troughs during the Meso-Neoproterozoic, causing a significant gravity loss on the gravity field, and formed considerable oil–gas exploration potential. Given suitable paleoclimatic conditions, the grabens would have provided a favorable environment for organic-rich shales and source rocks to develop. While the faults controlling the grabens and horsts would have played an important role in the migration and accumulation of hydrocarbons in the potential petroleum system. Combined with paleoclimate and lithofacies paleogeography analysis, five favorable areas are speculated for Meso-Neoproterozoic potential petroleum systems, which are the northwest Yimeng Uplift, the northern Tianhuan Depression, the southern Tianhuan Depression, the southwestern to central Yishaan Slope and the western Weibei Uplift, respectively. Based on lithofacies paleogeography, source rock maturity and organic carbon abundance, it suggests that the favorable petroleum systems within the Proterozoic strata of the Ordos Block were obviously controlled or influenced by the deep paleo-rifts and block faults, which resulted in forming three types of play, called the Weathering Model, the Tilting Model and the Transition Model. In particular, the central to western parts of the Yimeng Uplift and the southern Tianhuan Depression, where the Weathering Model developed, as the Upper Paleozoic coal-bearing source rocks have large hydrocarbon generation potential and good preservation conditions, these two areas should be regarded as important favorable prospecting regions in the Ordos Basin.

Mercury's Crustal Thickness Correlates With Lateral Variations in Mantle Melt Production

AbstractOver the first billion years of Mercury's history, mantle melting and surface volcanism produced a secondary magmatic crust varying spatially in composition and mineralogy. By combining geochemical mapping from MESSENGER with laboratory experiments on partial melting, we translate the surface mineralogy into lateral variations of surface density and calculate the degree of mantle melting required to produce surface rocks. If lateral density variations extend through the whole crust, the local crustal thickness correlates well with the degree of mantle melting. Low‐degree mantle melting produced a thin crust below the northern volcanic plains (19±3 km), whereas high‐degree melting produced the thickest crust in the ancient high‐Mg region (50±12 km), refuting the hypothesis of an impact origin for that region. The thickness‐melting correlation has also been observed for the oceanic crust on Earth and might be a common feature of secondary crust formation on terrestrial planets.

Prescience of endogenous regulation in Arabidopsis thaliana by Pseudomonas putida MTCC 5279 under phosphate starved salinity stress condition

Phosphorus (P) availability and salinity stress are two major constraints for agriculture productivity. A combination of salinity and P starvation is known to be more deleterious to plant health. Plant growth promoting rhizobacteria are known to ameliorate abiotic stress in plants by increasing the availability of different nutrients. However, interaction mechanisms of plant grown under salinity and P stress condition and effect of beneficial microbe for stress alleviation is still obscure. Earlier we reported the molecular insight of auxin producing, phosphate solubilising Pseudomonas putida MTCC 5279 (RAR) mediated plant growth promotion in Arabidopsis thaliana. In present study new trait of proline and phosphatase production of RAR and its impact on modulation of physiological phenomenon under phosphate starved-salinity stress condition in A. thaliana has been investigated. Different physiological and molecular determinants under RAR- A. thaliana interaction showed that auxin producing RAR shows tryptophan dependence for growth and proline production in ATP dependant manner under salinity stress. However, under P deprived conditions growth and proline production are independent of tryptophan. RAR mediated lateral root branching and root hair density through modulation of abscisic acid signalling was observed. Acidic phosphatase activity under P starved and salinity stress condition was majorly modulated along with ROS metabolism and expression of stress responsive/phosphate transporter genes. A strong correlation of different morpho-physiological factor with RAR + salt conditions, showed We concluded that enhanced adverse effect of salinity with unavailability of P was dampened in presence of P. putida MTCC 5279 (RAR) in A. thaliana, though more efficiently salinity stress conditions. Therefore, alleviation of combined stress of salinity induced phosphate nutrient deficiency by inoculation of beneficial microbe, P. putida MTCC 5279 offer good opportunities for enhancing the agricultural productivity.